IRON AND STEEL 
 

 *$ Qruw-Jf ill Book 60 7m 
 
 PUBLISHERS OF BOOKS F O R_, 
 
 Coal Age Electric Railway Journal 
 Electrical World v Engineering, News-Record 
 American Machinist v The Contractor 
 Engineering 8 Mining Journal ^ Power 
 Metallurgical 6 Chemical Engineering 
 Electrical Merchandising 
 
 
IRON AND STEEL 
 
 (A POCKET ENCYCLOPEDIA) 
 
 INCLUDING ALLIED INDUSTRIES 
 AND SCIENCES 
 
 BY 
 
 HUGH P. TIEMANN, B.S., A.M. 
 
 WITH AN INTRODUCTION 
 BY 
 
 HENRY MARION HOWE 
 
 SECOND EDITION 
 REVISED, ENLARGED AND ENTIRELY RESET 
 
 FIRST IMPRESSION 
 
 McGRAW-HILL BOOK COMPANY, INC. 
 239 WEST 39TH STREET, NEW YORK 
 
 LONDON: HILL PUBLISHING CO., LTD. 
 6 & 8 BOUVERIE ST., E.G. 
 
 1919 
 
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 COPYRIGHT, 1919, BY THE 
 MCGRAW-HILL BOOK COMPANY, INC. 
 
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 THE MAPLE PRESS YORK 
 
INTRODUCTION 
 
 IT is with gratitude as a reader, pride as a teacher, and pleasure 
 as a friend that I write a word of introduction to this admirable 
 work of my former pupil and long-time friend, the Author. 
 
 The jargon of the millman, like that of the philosopher, is a 
 deplorable necessity. It is a collection of invaluable special tools 
 for special men doing special work. When the dentist and the 
 obstetrician regard the unfathomable mysteries of each other's 
 "kits," each has the consolation that he need not attempt the fath- 
 oming. But alas, you and I cannot thus escape each other's jargon, 
 for the metallographist must needs learn from the millman and the 
 millman from the metallographist, and each has become the slave of 
 his own tools, his own jargon. He talks and perhaps thinks in terms 
 of it, if indeed we think in any language, which I doubt At least, 
 if he thinks in any language it is in his jargon. Life is too short, 
 patience too flimsy, to permit our forcing our thoughts into others' 
 minds by means of any tools other than our own jargon. The 
 Author gives me an admirable case in point. 
 
 Foreman: "How does this steel work?" 
 
 Heater: "If you don't wash it, it won't clean." 
 
 This is "short hand" for: "The iron oxide or 'scale' which forms 
 on the surface of this steel adheres so firmly that, unless it is heated 
 so highly that it melts, some of it will cleave to the metal during 
 the operation of rolling, and hence will deface the finished plates 
 into which the steel is to be rolled." The heater's words are not 
 English; they are jargon, and it is proper that they should be. If 
 he persisted in translating them into English as I have done, and in 
 talking English in general, he would simply justify the dismissal 
 which would surely come. The guild has evolved its jargon for its 
 own use. To replace it with the King's English would be about 
 as unwise as to replace it with French or modern Greek, or to replace 
 "short hand" with "long hand" in the reporting of debate. 
 
 When the metallographist and millman meet, it is as the meeting 
 of French and Greek. The millman scolds the metallographist, 
 yes, and I have had to endure with my scanty patience many such 
 scoldings for deliberately inventing jargon, useful for the metallo- 
 graphic guild, but a stumbling block to the millman. Of course 
 it is not I but the nature of things that ought to be scolded; but 
 then it is pleasanter and less transparently foolish to scold me, 
 especially if I have previously earned your gratitude by disen- 
 tangling some of your fallacies and sophisms. 
 
 392156 
 
vi INTRODUCTION 
 
 Now here comes the gallant Author to the aid of fumbling metal- 
 lographist and irritated millman. With infinite pains, ingenuity, 
 and skill he blesses both where they had banned each other, and 
 enables the brothers to dwell together in harmony, unfolding to each 
 the jargon of the other by means of a tri-lingual dictionary, trans- 
 lating the jargons of both into the common language, English. 
 
 Nor are they alone his debtors. Having long lived a metallog- 
 raphist and a teacher among the millmen, he discloses clearly, 
 tersely, and graphically the manners and customs of the millmen, 
 to wit the how and the why of their actual practice, as only a resi- 
 dent can know it. In short, he describes the actual metallurg- 
 ical operations and apparatus in a way which seems to me most 
 admirable. 
 
 I .commend the book without reserve to the whole family of steel 
 metallurgists, be they millmen, metallographists, teachers, or 
 students. 
 
 HENRY M. HOWE. 
 
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PREFACE TO SECOND EDITION 
 
 THE present revision is the result, not only of certain omissions 
 and shortcomings in the first edition, but also of the friendly 
 reception and the helpful criticism accorded it. 
 
 The vast amount of time consumed in no way evident from 
 the result in consulting references and authorities, collecting data, 
 and condensing and practically rewriting the whole of the text, all 
 of which had to be done without interference with regular business, 
 prevented the completion of the task at an earlier date. It is 
 hoped that an improvement will be found both in regard to the 
 additional information and the method of treatment. The num- 
 ber of terms, and the text also, has been increased about fifty per 
 cent. 
 
 The general processes of manufacture have undergone but little 
 change, the principal development being in the greatly increased 
 use of the electric furnace. The chief increase in the text is due 
 to more extended discussions of subjects, such as heat treatment, 
 physical properties, and testing, and to the numerous investiga- 
 tions of the more theoretical aspects of the subject, particularly 
 those included under metallography. 
 
 For the benefit of those little versed in the metallurgy of iron 
 and steel, and who may desire a guide to a more sequential and 
 hence logical study than is afforded by the alphabetical arrange- 
 ment of the text (which still seems best for ready reference) a brief 
 outline of the metallurgy of iron and steel has been prepared which 
 will be found immediately preceding the text. 
 
 Among a number of kind friends whose assistance is deeply ap- 
 preciated, the author desires to express his thanks especially to 
 D. M. Buck (Corrosion and Protection), L. J. Gray (Gages), E. S. 
 Humphreys (Sheets and Tin Plate), E. A. Kebler (Pig Iron), and 
 J. O. Leech (Specifications); the opportunity cannot be allowed to 
 pass of calling attention to the cordial cooperation of the publishers, 
 whose assistance in practical suggestions and care in the make-up 
 of the book have contributed in no small degree to whatever success 
 it has achieved. 
 
 H. P. T. 
 
 PITTSBURGH, PA., 
 December, 1918. 
 
 vn 
 
PREFACE TO FIRST EDITION 
 
 OWING to the close relationship with other industries, such as 
 coal, coke, etc., and from the fact that certain branches of science 
 are involved in metallurgy, terms applying to these have been in- 
 cluded in this book, in so far as they are commonly met with in the 
 literature of iron and steel. In general, subjects of a mechanical 
 or of an engineering nature have not been considered, as they are 
 dealt with in the handbooks devoted especially to them. It may 
 be found, however, that in some cases subjects have been incorpo- 
 rated which seem superfluous in a work of this character. 
 
 It has been the endeavor to make the book as compact as possible, 
 at the same time giving sufficiently full explanations for ordinary 
 purposes so that to the metallurgist who wishes to refresh his mind 
 on _some term rarely used, and to the person only slightly familiar 
 with the ground, it may prove equally useful. 
 
 The general treatment, then, is a combination of a dictionary, a 
 cyclopedia, and a handbook, possessing as well as omitting some 
 of the features of all. The definitions or descriptions of isolated 
 terms or processes are found under the respective headings, while 
 those employed .in connection with some special subject or process 
 are found under the latter, reference being made, as a rule, by page 
 numbers instead of by titles. In this way, the reader who desires 
 enlightenment upon a single point, as well as he who is unfamiliar 
 with the subject as a whole or who wishes to learn the terms used 
 in a certain process, may do so as readily and as simply as possible. 
 
 Among the many authorities consulted, the most important is 
 unquestionably the Journal of the Iron and Steel Institute, which 
 is a veritable mine of information. The writer whose books have 
 been drawn upon most largely is Prof. Henry M. Howe, who pos- 
 sesses in the highest degree the unusual and happy faculty of ex- 
 pressing what he has to say both clearly and concisely. 
 
 The Author's thanks are due to many good friends for the 
 timely criticism and advice which they were ever ready to give. 
 Among those to whom he is especially indebted are the following: 
 J. W. Benner, W. A. Bostwick, Prof. William Campbell, Prof. Henry 
 M. Howe, E. T. Ickes, Eliot A. Kebler, C. F. W. Rys, and Bradley 
 Stoughton. 
 
 In conclusion, the Author will be most grateful to any one calling 
 his attention to errors of omission as well as of commission. 
 
 H. P. T. 
 
 PITTSBURGH, PA., 
 November, 1910. 
 
 ix 
 
-'oiTKl/T 
 
OUTLINE OF 
 THE METALLURGY OF IRON AND STEEL 
 
 The term iron has such a variety of applications that, if used by 
 itself, the exact meaning cannot be determined. In its chemical 
 sense it refers to the element (see Chemistry), either isolated or 
 combined with other elements; e.g., the percentage of the element 
 present in metallic substances, iron ores, etc. In its metallic con- 
 dition the carbon content (either expressed or implied) is the de- 
 termining factor. In this case "iron" may refer to (a) the nearly 
 pure substance (see Electrolytic Iron); (b) the product nearly free 
 from carbon, more specifically known as wrought (malleable} iron or 
 puddled iron; or (c) where the carbon content is high, termed cast 
 iron or pig iron. Steel is the present name for iron produced by any 
 process, in a fluid condition thereby permitting nearly complete 
 elimination of slag, and containing any amount of carbon up to a 
 content where it can no longer be usefully worked. Before the 
 appearance of the Bessemer process, the classification provided for 
 (a) iron, low in carbon, which was malleable and could not be use- 
 fully hardened, produced by a direct process or by puddling; (6) 
 steel (higher in carbon) which was also malleable but could be use- 
 fully hardened, produced in the same way as iron and called wrought 
 steel; by the conversion (carburization) of wrought iron into steel 
 by cementation (q.v.), the product being denominated blister bars 
 or cement bars and used as such (blister steel) or remelted in the 
 crucible process for crucible steel or cast steel; (c) cast iron as described 
 above, so named because it could not be worked but could be given 
 the desired form only by casting when molten into molds. 
 
 Metallic iron or steel is not found naturally in that condition. 
 An apparent exception is the case of certain meteorites (q.v.). As 
 it exists in chemical combination with other elements, principally 
 as an oxide, and mechanically mixed with a certain amount of 
 earthy matter (chiefly sand or clay), occurring in deposits known 
 as ore (see Iron Ore), it becomes necessary to reduce it to the 
 metallic state by an operation known as smelting. This is accom- 
 plished practically exclusively by carbon occurring in some form of 
 solid fuel, such as coke, coal, or charcoal, which serves not only as 
 the medium of reduction, but also for producing by combustion 
 the heat (temperature) required to carry on this reaction. The 
 heat for this and other processes is occasionally supplied by some 
 other agency such as electricity (see Electric Processes). 
 
xn THE METALLURGY OF IRON AND STEEL 
 
 The quality of an ore can. in various cases be materially improved 
 by roasting to burn away impurities, or by washing away a con- 
 siderable portion of the earthy matter or gangue (see Ore). It may 
 also be desirable to agglomerate fine ore or similar material into 
 hard tenacious pieces or lumps (see Briquette). 
 
 In the production of metallic iron two conditions are necessary: 
 
 1. Reduction of the iron oxide, i.e., elimination of the oxygen 
 with which it is chemically combined; effected by part of the carbon 
 of the fuel. 
 
 2. Separation and removal of the gangue with which it is mechan- 
 ically mixed; usually by the addition of a substance or flux with 
 which it unites to form a more fusible compound or slag. 
 
 Iron can be partially reduced at relatively low temperatures, e.g., 
 by carbon monoxide gas, and completely reduced at somewhat 
 higher temperatures but still considerably below its melting point, 
 by contact with hot carbonaceous matter. It is the latter method 
 which was originally employed because the necessary temperature 
 was readily secured by simple equipment such as a hole dug in a 
 hillside where the prevailing winds supplied the air for combustion 
 through suitable apertures in the roof. Soon, however, 'advances 
 were made by developing. a fireplace or hearth where charcoal could 
 be burned intermixed with rich ore. Part of the ore was reduced 
 and part was lost in slagging off the gangue. The reduced pasty 
 iron collected at the bottom together with molten slag or portions 
 of the original charge: additional fuel and ore could be thrown in 
 through an opening in the front. However, as the size of the 
 equipment was increased it was found advantageous to do the 
 charging through a hole in the top or stack. 
 
 When natural draft failed to supply air at the necessary rate and 
 pressure, bellows were substituted, and these, in turn, were replaced 
 by some form of blowing engine (see Direct Processes). Greater 
 height of stack, better insulation against loss of heat, and more 
 rapid combustion all led to increased temperature (see Heat), and 
 also more and more carbon was absorbed by the metal. Finally 
 the condition was reached where the melting point of the iron was 
 lowered sufficiently by the increased absorption of carbon to be 
 below the temperature of reduction, and the product was then 
 obtained in a liquid (molten) state. It was accordingly run or 
 poured (cast) into suitable molds and hence was termed cast iron. 
 
 While at first, due to variations in temperature, the iron from 
 the same furnace was sometimes pasty and sometimes molten, it 
 was quickly realized that the greatest output and ease of handling 
 resulted from the latter condition, hence the necessary steps were 
 taken to make this condition permanent and resulted in the devel- 
 opment of the present blast furnace (q.v.). 
 
 At the high temperature of the blast furnace nearly all the iron, 
 manganese, and phosphorus are reduced and also certain proportions 
 of silicon, sulphur, and other elements present. The high contents 
 of elements other than iron prevent cast iron from being usefully 
 malleable at any temperature, so that it must be given the desired 
 form by pouring when molten into molds. If a malleable product 
 
THE METALLURGY OF IRON AND STEEL xiii 
 
 is desired the excess of these constituents (which therefore become 
 in this sense impurities) must be removed by some refining process 
 (see Purification). 
 
 The production of steel in two stages, i.e., first as cast iron and 
 second by subsequent refinement into steel, is termed an indirect 
 process or method in contradistinction to the direct process in which, 
 as described, the operation is arrested before the iron has absorbed 
 any considerable quantity of carbon and consequently is still 
 malleable. 
 
 Purification usually consists in oxidation carried to the point 
 where the impurities or excess constituents are nearly all removed, 
 or to the extent desired. As explained in Chemistry, it consists 
 in causing these ingredients to combine with oxygen in which con- 
 dition they pass into the slag if solid (or molten), or escape into 
 the air if gaseous. 
 
 The terms acid and basic, whether applied to steel or a process, 
 refer to the nature of the slag and the corresponding refining action 
 which is occasioned. Since the effect of a given kind of slag should 
 be confined to the charge, the lining of the containing vessel or 
 furnace should be of the same nature, to remain nearly unaffected, 
 thus giving rise to acid (lined) or basic (lined) vessels or furnaces. 
 
 Under oxidizing conditions the metalloids such as phosphorus 
 and silicon can be eliminated by causing their oxides which are 
 acid, to combine with, and be retained by, a base such as lime if 
 this is present in sufficient excess. Sulphur presents certain diffi- 
 culties to removal under oxidizing conditions, and the extent of its 
 removal is usually erratic. In the elimination .of impurities (basic 
 process), at a relatively low temperature phosphorus and silicon 
 are acted upon and eliminated in preference to the carbon, but if 
 the temperature is high the carbon is immediately affected, which 
 may result in less perfect elimination of the first named. 
 
 Under strongly reducing conditions, such as can be secured in 
 the blast furnace or the electric furnace, the removal of the sulphur 
 is under fairly constant control; also at very high temperatures 
 it is claimed that phosphorus previously brought into the slag by 
 oxidizing conditions can, by powerful reduction, as in the electric 
 furnace, be converted into an even more stable phosphide. 
 
 There are two principal sources of oxygen (a} iron oxide, and (/>) 
 air, which are used either separately or in combination. 
 
 In puddling (q.v.) pig iron is melted on the hearth of a reverbera- 
 tory furnace (see Furnace), in contact with iron oxide and exposed 
 to the flame; in the charcoal hearth processes (q.v.) the pig iron is 
 exposed in a hearth to the action of a blast in conjunction with the 
 gas resulting when the fuel consisting of charcoal is burned to 
 yield the necessary temperature. In both cases the product be- 
 comes pasty in its later stages and contains an admixture of slag 
 most of which is expelled by subsequent hammering or rolling. The 
 open hearth process (q.v.) is similar to puddling but, owing to the 
 method of heating, the temperature is at all stages maintained above 
 the melting point of the metal, and hence the product is fluid which 
 permits of a nearly complete separation from the slag. The Bes- 
 
xiv THE METALLURGY OF IRON AND STEEL 
 
 semer process (q.v.) employs air alone which is blown through the 
 molten metal. 
 
 The oldest method for producing steel in the fluid condition is 
 the crucible process (q.v.) which consists principally in the remelting 
 of suitable materials, with little if any purification aside from the 
 elimination of oxides. 
 
 The final adjustment of the composition is described in connec- 
 tion with the various steel making processes, and consists essentially 
 in adding the necessary ingredients for this purpose and also for 
 that of deoxidation (see also Recarburization). 
 
 The properties of iron are chiefly affected by the carbon content, 
 and most of the iron or steel of commerce contains this element as 
 its principal constituent, together with varying amounts of man- 
 ganese, phosphorus, sulphur, and silicon, together with certain other 
 special elements, usually in traces, depending upon the nature or 
 the source of the ore. Special steels (q.v.) contain one or more 
 special elements, such as nickel, chromium, tungsten, etc., delib- 
 erately added (or present) in amounts sufficient to affect appreci- 
 ably the physical properties. These serve both to intensify the 
 effect of carbon, as well as to modify the general or specific proper- 
 ties, but without carbon their value would be greatly diminished. 
 
 It is possible under the proper conditions to add carbon to 
 (carburize) the steel at temperatures considerably below its melting 
 point, by heating in intimate contact with carbonaceous matter, 
 and with exclusion of air or other oxidizing media. The process 
 is relatively slow in comparison with treatment in the molten state, 
 the time being roughly inversely as the temperature. A piece 
 carburized only to a slight depth, to produce better wearing prop- 
 erties, is said to be case hardened. The process may be carried 
 further so that all or nearly all the section is affected. This subject 
 is discussed under Cementation and Cementation Process. 
 
 While cast iron as such is not usefully malleable, and is more 
 brittle the greater the proportion of carbon in the combined state, 
 it is possible to restore this property to a considerable degree. This 
 is accomplished by heating white iron (see Pig Iron) castings in 
 contact with iron oxide, at a temperature below their melting point, 
 by which means the carbon is oxidized or converted into inert 
 graphite. These are termed malleable castings (q.v.). 
 
 In the case of liquid steel, after the composition has been adjusted 
 in the furnace or the ladle into which it is tapped, it is poured into 
 molds (see Casting and Molding) producing castings which, if to 
 be worked, are known as ingots. These are then forged or rolled 
 to shape as described under Forging, Pressing, and Rolling. 
 
 The chemical composition is determined by analytical methods 
 (see Chemistry) and the physical properties (q.v.) are checked by 
 some method of testing (q.v.). 
 
 The investigation of the nature of the physical constitution and 
 
 or! hn .. 1 
 
THE METALLURGY OF IRON AND STEEL XV 
 
 conditions which are responsible for the physical properties shown, 
 is dealt with under Metallography. 
 
 The structure may be advantageously or injuriously affected by 
 purely thermal treatment (see Heat Treatment) or by the mechan- 
 ical working to which it has been subjected (see Heat Treatment 
 and Cold Working). 
 
 The joining together of two pieces, either in a pasty condition or 
 by actual fusion commonly known as welding, is discussed under 
 that heading. 
 
 The causes for the deterioration or rusting of iron products, 
 whereby the metal tends to return to its original oxidized state, 
 and the conditions or methods which retard or overcome this 
 tendency are dealt with under Corrosion and Protection. 
 
 The manufacture of general products, such as plates, shapes and 
 bars, is considered under Rolling, while special products, such as 
 sheets and tin plate, tubes, and wire, are dealt with more fully 
 under their respective headings. 
 
IRON AND STEEL DEFINITIONS 
 
 A. (i) Chemical symbol for argon: see page 84; (2) critical point 
 of Tschernoff: see page 265; (3) for coating: see page 433. 
 
 Ai,A2,Aa.- Critical points: see page 264. 
 
 Aci, etc. Critical points: see page 264. 
 
 Ac CTO . Critical point: see page 264. 
 
 A CTO . Critical point: see page 264. 
 
 Ae, Aei, etc. Critical points: see page 264. 
 
 Ag. Chemical symbol for silver (from the Latin argentum): see 
 page 84. 
 
 Al. Chemical symbol for aluminum (q.v.). 
 
 Ar . Critical point: see page 264. 
 
 ATI, etc. Critical points: see page 264. 
 
 Ar CTO . Critical point: see page 264. 
 
 Ar OTC . Critical point: see page 264. 
 
 As. Chemical symbol for arsenic : see page 84. 
 
 Au. Chemical symbol for gold (from the Latin aurum): sec 
 page 84. 
 
 A. A. S. M. Association of American Steel Manufacturers. 
 
 A. B. M. A. American Boiler Makers' Association. 
 
 A. E. R. A. American Electric Railway Association, formerly the 
 American Street & Interurban Electric Railway Association. 
 
 A. E. R. E. A. American Electric Railway Engineering Associa- 
 tion, one of the subsidiary associations of the A. E. R. A. 
 
 A. E. R. M. A. American Electric Railway Manufacturers' Asso- 
 ciation, one of the subsidiary associations of the A. E. R. A., 
 composed of manufacturers of electric railway supplies. 
 
 A. F. A. American Foundrymen's Association. 
 
 A. I. M. E. American Institute of Mining Engineers. 
 
 A. O. H. Acid open hearth: see page ^3 09. 
 
 A. R. A. American Railway Association. 
 
 A. R. E. & M. W. A. American Railway Engineering & Mainten- 
 ance of Way Association; name changed (1911) to American 
 Railway Engineering Association. 
 
 A. R. E. A. American Railway Engineering Association; formerly 
 the American Railway Engineering & Maintenance of Way Asso- 
 ciation; one of the subsidiaries of the A. R. A. 
 
 A. R. M. M. A. American Railway Master Mechanics' Associa- 
 tion; one of the subsidiaries of the A. R. A. 
 
 A. S. C. E. American Society of Civil Engineers. 
 
 A . SI & I. E. R. A. American Street & Interurban Electric Rail- 
 way Association; name changed (1910) to A. E. R. A. 
 
 A. S. M. E. American Society of Mechanical Engineers. 
 
 A. S. T. M. American Society for Testing Materials. 
 
 A. S. & W. Gage. American Steel & Wire Co.'s Gage; see page 188 . 
 
2 ABEL'S CARBIDE -ADJUSTABLE TUYERE 
 
 Abel's Carbide of ITOK. Cementite: see page 272! 
 
 Abrasion. See pages 106 and 331. 
 
 Abrasive Hardness. See pages 331 and 478. 
 
 Abscissa. See Curve. 
 
 Absolute Scale. Of temperature: see page 205. 
 
 Absolute Strength. See page 468. 
 
 Absolute Temperature. See page 205. 
 
 Absolute Zero. See page 205. 
 
 Absolutely Black Body. See page 207. 
 
 Absorbed Energy. See page 481. 
 
 Absorbens. See page 120. 
 
 Absorption. See pages 199, 212 and 328. 
 
 Absorption Point. See page 265. 
 
 Absorption Pyrometer, Fery. See page 207. 
 
 Absorption Temperature. See page 265. 
 
 Absorption Zone. See page 292. 
 
 Accelerated Corrosion Test. See page 107. 
 
 Accelerated Stress. See page 333. 
 
 Achondrite. See page 292. 
 
 Acicular Crystal. See page 126. 
 
 Acicular Martensite. See page 275. 
 
 Acid. See page 88. 
 
 Acid Bessemer Ore. See page 243. 
 
 Acid Bessemer Pig. See page 343. 
 
 Acid Bessemer Process. See page 15. 
 
 Acid Bessemer Steel. Steel made by the acid Bessemer process. 
 
 Acid Bottom. See Lining. 
 
 Acid Brittleness. See page 507. 
 
 Acid Clay. See page 396. 
 
 Acid Converter. See page 16. 
 
 Acid Flux. See Flux. 
 
 Acid Lining. See Lining. 
 
 Acid Open Hearth Process. See pages 309 and 314. 
 
 Acid Open Hearth Steel. Steel made by the acid open hearth 
 
 process. 
 
 Acid Refractories. See page 395. 
 Acid Slag. See Slag. 
 Acid Theory of Corrosion. See page 107. 
 Acierage. The electro-deposition of a thin layer of iron on engraved 
 
 copper plates to make them more resistant to the wearing action 
 
 of inking and printing. 
 Acoustic Signals. See page 210. 
 Actinometer, Violle's. See page 207. 
 Active Combustion. See page 202. 
 Adamantine Silicon. See Silicon. 
 Adams Process. See page 137. 
 Addie Process. For the recovery of tar and ammonia from the gas 
 
 of a blast furnace using raw coal. 
 Additions. For recarburizing : see page 393. 
 Additional Strains; Stresses. See page 332. 
 Additive Property. See page 337. 
 Adjustable Tuyere. See page 182. 
 
ADJUSTING PROCESS AIRED BARS 3 
 
 Adjusting Process (Howe). One in which the composition is 
 determined and arranged. 
 
 Adsorption. See page 328. 
 
 Adsorption Theory. Of passivity: see page 364. 
 
 Advance Alloy. For thermo-couples: see page 209. 
 
 Aeolic. See page 270. 
 
 Aeolic Steel. See page 273. 
 
 Aeoliochronous. Or Aeoliotachic ; suggested by Howe to express 
 the fact that cooling and contraction, even if equal in amount, 
 occur at different rates in different portions of a piece. 
 
 Aeoliotachic. See Aeoliochronous. 
 
 Aeolotropic. See page 330. 
 
 Aerolite. See page 290. 
 
 Aerolitics. See page 291. 
 
 Aerosiderite. See page 291. 
 
 Aerosiderolite. See page 291. 
 
 Affinity. See page 84. 
 
 After Blow. See page 21. 
 
 After Glow (rare). Recalescence : see page 265. 
 
 Aggregate. See page 264. 
 
 Aging. See page 333. 
 
 Agglomeration. See page 81. 
 
 Aggregation, State of. See page 81. 
 
 Agitator, Allen's. See page 62. 
 
 Agraphitic Carbon. See pages 50 and 278. 
 
 Air Belt See page 182. 
 
 Air Box. See page 17. 
 
 Air Casing. A casing enclosing air to prevent or reduce loss of heat 
 by radiation. 
 
 Air Chamber. See page 182. 
 
 Air Channels. Flues under the hearth and the fire-bridge of a 
 reverberatory furnace to keep them cool. 
 
 Air Cooling. See pages 227 and 232. 
 
 Air-dilution Pyrometer. See page 210. 
 
 Air Dry. Dried by simple exposure to the air, without the appli- 
 cation of heat. 
 
 Air Furnace. See page 182. 
 
 Air Gas. See Oil Gas. 
 
 Air Hardening. See page 227. 
 
 Air-hardening Steel. See page 445. 
 
 Ah* Heating. Heating in air. 
 
 Air Pits (Ewing and Rosenhain). An epithet applied to micro- 
 scopic air bubbles, which have taken a geometrical form, found on 
 the surface of certain metals cast on glass. 
 
 Air Pyrometer. See page 205. 
 
 Air-quenched Steel. See page 445. 
 
 Air Quenching. See page 227. 
 
 Air Refining Process. Bessemer Process, q.v. 
 
 Air Thermometer. See page 205. 
 
 Air Tinting. See page 288. 
 
 Air Toughening. See page 232. 
 
 Aired Bars. See page 71. 
 
4 AKERMAN'S THEORY ALLOY 
 
 Akennan's Theory. Of hardening : see page 280. 
 
 Alexander and M'Cosh Process. For the recovery of tar and am- 
 monia from the gas of a blast furnace using raw coal. 
 
 All-mine Pig. See page 350. 
 
 Allen's Agitator. See page 62. 
 
 Allevard Process. See page 154. 
 
 Alligator Cracks. See page 112. 
 
 Alligator Scale. A heavy, very infusible scale formed during the 
 reheating of chrome steel. 
 
 Alligator Shears. See Shears. 
 
 Alligator Squeezer. See page 377. 
 
 Alling's Test. See page 216. 
 
 Allis-Andrew Process. See page 416. 
 
 Allomorph. See page 122. 
 
 Allotrimorphic Crystal. See page 122. 
 
 Allotropic Modifications. Of iron: see page 264. 
 
 Allotropic Theory. Of hardening: see page 279. 
 
 Allotropic Transformation. See page 327. 
 
 Allotropy. A change in the properties of an element without change 
 of state. It is habitually accompanied by a change of internal 
 energy. It is due in some, and perhaps in all, cases to a 
 change in the number or in the arrangement of the atoms in the 
 molecule (Howe). Allotropic varieties are sometimes termed 
 isomerides. 
 
 Alloy. A union, possessing metallic properties, of two or more 
 metallic elements, or of metallic elements and metalloids, which 
 are miscible with each other, at least to a certain extent, when mol- 
 ten to form a homogeneous liquid, and do not separate into dis- 
 tinct layers when solid. Such combinations when cold may con- 
 sist of mechanical mixtures, eutectics or eutectoids, solid solu- 
 tions, or chemical compounds, one or more of which may exist 
 at the same time. Amalgamation is the alloying of mercury with 
 some other metal yielding (at least temporarily) a plastic or liquid 
 mass; the term is sometimes used improperly, where mercury is 
 absent, in the ordinary sense of alloying. When composed of 
 two or more elements they are termed respectively binary, ter- 
 nary, quarternary alloys, etc. An alloy, composed of metallic 
 elements only, is sometimes referred to as a metallic, intermetal- 
 lic, or simple alloy ; where a definite chemical compound exists, it 
 may be termed an intermetallic compound or definite alloy; a 
 mixture of the two, a metallo-metallic compound; a eutectomeric 
 alloy is one which, in one proportion of its constituents, forms a 
 eutectic. The dominant metal or element is one which princi- 
 pally affects the properties. Alloys may be divided into ferrous 
 and non-ferrous depending on whether or not iron is the dominant 
 element. They may also be classified as heavy, where they con- 
 tain principally metals such as iron, nickel, or copper with a 
 specific gravity over about 7; and light, with,metals with a specific 
 gravity less than this. Fusible alloys are those which melt at a 
 very low temperature, e.g., Wood's fusible alloy which melts at 
 65 C. (149 F.) ; they usually consist of bismuth, lead and tin in 
 various proportions, and iron only as an impurity. Magnetic 
 
ALLOY 5 
 
 alloys (generally referred to as Heussler's alloys) do not contain 
 iron but consist of metals which, separately, are non-magnetic or 
 only slightly so;' the composition may be taken as approximately 
 copper 60, manganese 20, aluminum 14. Overbeck suggested 
 the term metamagnetic alloys for those which are paramagnetic 
 or diamagnetic, according to the strength of the magnetic field 
 the case of some alloys of copper and zinc. Hannover's process 
 for making metallic sponges consists in heating a eutectic alloy 
 to a temperature within its freezing range (see Metallography, 
 page 267) and centrifuging it, whereby the molten portion is 
 expelled. What is known as the superposing method of forming 
 alloys consists in first melting the metal of highest specific gravity 
 and then pouring on top of this, in a molten condition, the other 
 and lighter metal. The two metals will alloy in such a way that 
 a vertical cross section will show crystals of a pure metal at one 
 end and crystals of the other metal at the other end, while be- 
 tween these the metals will be found alloyed in all possible pro- 
 portions (Metallographist, 1902, 247). (For further details of 
 the constitution and properties of alloys see the treatises on the 
 subject by Howe, Sauveur, Desch, Heyn, Rosenhain, Guertler, 
 etc., also Metallography). 
 
 Alloy Cast Iron. See page 351. 
 
 Alloy Element. See pages 351 and 443. 
 
 Alloy Steels. See page 443. 
 
 Alloyed Carbon Iron. See page 443. 
 
 Almond Furnace. A remelting or refining furnace of the reverbera- 
 tory type; name derived from allemand (German). 
 
 Alpha Cementite; See page 273. 
 
 Alpha (a) Iron. See pages 264 and 272. 
 
 Alpha Iron Theory; Alpha Theory. Of hardening: see page 280. 
 
 Altar. Of a furnace: see pages 183 and 375. 
 
 Altered Iron. See page 364. 
 
 Alternate Stresses. See page 333. 
 
 Alumaloyd. See page 372. 
 
 Aluminium (Eng.). See Aluminum. 
 
 Alumino-ferrite. See page 272. f 
 
 Alumino -thermic Process. Carried out by means of the heat 
 developed by the burning (oxidation) of metallic aluminum; see 
 Goldschmidt process- and Rossi process. 
 
 Aluminous Clay. See page 396. 
 
 Aluminum. Al; at. wt, 27; melt, pt., 625 C. (1157 F.); sp. gr., 
 2.58 (by hammering or rolling this may be raised to 2.68). A 
 white metal, with high tensile strength, malleability, and con- 
 ductivity. Its principal application in the manufacture of steel is 
 as a deoxidizer, for which purpose it is usually added (up to about 
 3 or 4 oz. per ton) in the mold during pouring. It is used as the 
 pure metal, or as an alloy with iron called ferro-aluminum (see 
 page 351), and is rarely a constituent/) f steel (see page 453). 
 
 Aluminum Coating. See page 372. 
 
 Aluminum Steels. See page 453. 
 
 Alundum. A trade name for an abrasive consisting of fused alu- 
 mina, produced in the electric furnace. 
 
6 AMALGAMATION ANNEALING CHARGE 
 
 Amalgamation. See Alloy. 
 
 American Bloomary Process. See page 137. 
 
 American Charcoal Irons. See page 350. 
 
 American Forge. See page 137. 
 
 American Forge and Foundry Iron. Graded by analysis: see page 
 348; graded by fracture; see page 347. 
 
 American Lancashire Process. See page 77. 
 
 American Process. For malleable castings: see page 258. 
 
 American Steel & Wire Co.'s Gage. See page 188. 
 
 American Wire Gage. See page 188. 
 
 Amet-Ensign Oil Gas Producer. See Oil Gas. 
 
 Amianthus. See Salamander. 
 
 Amorphizing. See page 282. 
 
 Amorphous. See page 119. 
 
 Amorphous Antimony. See Antimony. 
 
 Amorphous Boron. See Boron. 
 
 Amorphous Carbon. See Carbon. 
 
 Amorphous Cement Theory. See page 281. 
 
 Amorphous Fracture. See page 178. 
 
 Amorphous Iron Theory. Of hardening: see page 281. 
 
 Amorphous Phase. See page 281. 
 
 Amorphous Silicon. See Silicon. 
 
 Amorphous State. See page 281. 
 
 Amorphous Sulphur. See Sulphur. 
 
 Amorphous Theory. Of hardening: see page 281. 
 
 Amorphous Tin. See Tin. 
 
 Amount of Heat. See page 199. 
 
 Amsler-Laff on Test. (i) Hardness test: see page 47 8; (2) vibratory 
 test: see page 482. 
 
 Analysis; analytic (al) Chemistry. See page 82. 
 
 Analytical Reaction. See page 87. 
 
 Anchor Bolt. In molding: see page 299. 
 
 Ancony (obs.). See page 135. 
 
 Anderson Furnace. See page 154. 
 
 Angle of Contact. In rolling: see page 407. 
 
 Angular Fracture. See page 179. 
 
 Angular Method of Rolling. See page 420. 
 
 Anhedrpn. See page 122. 
 
 Anhydride. See page 88. 
 
 Anion. See page 89. 
 
 Anion Discharge Theory. Of passivity: see page 364. 
 
 Anisometric System. Of crystallization: see page 120. 
 
 Anisotropic ; Anisotropy. See page 330. 
 
 Ankerite. A crystallized variety of dolomite containing a large pro- 
 portion of iron. 
 
 Ankony (obs.). Double gross ton of 2464 pounds. 
 
 Annealing. (i) Of crucibles: see page 112; (2) of steel or iron: 
 page 231; -(3) of malleable castings: see page 258; (4) of sheets: 
 see page 431; (s) of tubes: see page 492. 
 
 Annealing Box. See page 431. 
 
 Annealing Carbon. See pages 257 and 278. 
 
 Annealing Charge. See page 233. 
 
ANNEALING FURNACE ARC-RESISTANCE FURNACE 7 
 
 Annealing Furnace. A type of furnace used for annealing, i.e., 
 heating to a low temperature: see Furnace. 
 
 Annealing Oven. For crucibles: see page 112. 
 
 Annealing Pit. A pit, generally lined with brick, in which castings, 
 particularly cast-iron car wheels, are allowed to cool slowly. 
 
 Annealing Pot. See pages 258 and 431. 
 
 Annealing Temperature. The temperature to which material is 
 heated for annealing. 
 
 Annealing Twin. See page 125. 
 
 Anode. See page 89. 
 
 Anodic Passivity. See page 364. 
 
 Anodic Polarization. See page 364. 
 
 Anorthic System. Of crystallization: see page 120. 
 
 Ansaldo Process. See page 60. 
 
 Anthracite ; anthracite coal. See Coal. 
 
 Anthracite Coal Apples. See Coal. 
 
 Anthracite Furnace. Kind of blast furnace : see page 39. 
 
 Anthracite Pig. See page 343- 
 
 Anthracitic Coal. See Coal. 
 
 Anti-cement. In cementation: see pa'ge 70. 
 
 Anti -fatigue Steel. See page 452. 
 
 Anti-friction Metal. A bearing metal, such as babbitt, used to re- 
 duce the friction of bearings. It usually consists of various pro- 
 portions of lead, tin, zinc, and antimony. 
 
 Antimony. Sb; at. wt, 120; melt, pt, 630 C. (1166 F.); sp. gr. f 
 crystalline, 6.7 to 6.8, amorphous, 5.78. It is found in the free 
 state, but its most important occurrence is in combination with 
 other elements. When pure it is a white brittle metal. It is not 
 of value as a constituent of steel, as it is generally considered that 
 even very small percentages render it both hot and cold short. 
 Metallic antimony as found on the market is sometimes known as 
 French metal. 
 
 Anti-piping Thermit. See page 61. 
 
 Anvil; Anvil Block. See Hammer. 
 
 Anvil Effect. The effect on rails due to pounding of flat wheels and 
 lack of counterbalance of driving wheels. Especially pronounced 
 when the track is frozen. The road bed is considered as forming 
 the anvil, on which the rails receive the hammer-like blows of the 
 wheels. 
 
 Aphanitic Fracture. See page 178. 
 
 Apparent Elastic Limit. See page 470. 
 
 Apparent Stress. See page 332. 
 
 Apple. Coal. See Coal. 
 
 Applied Chemistry. See page 81. 
 
 Aproning. In puddling: see page 377. 
 
 Aqua Regia. See page 84. 
 
 Aqueo-igneous Fusion; Aqueous Fusion. See page 201. 
 
 Arbitration Bar. See page 484. 
 
 Arborescent Crystal. See pages 55. 
 
 Arc Furnace; Heating. See page 153. 
 
 Arc Radiation Furnace. See page 153. 
 
 Arc-resistance Furnace. See page 153. 
 
8 ARC WELDING ARMOR PLATE 
 
 Arc Welding. See page 503. 
 
 Argillaceous. Containing or consisting of clay. 
 
 Argillaceous Iron Ore; Siderite. See page 244. 
 
 Armco Iron. The trade name for so-called "ingot iron," extremely 
 low in carbon and other elements, produced by a special open 
 hearth process. 
 
 Armor Plate. Special, usually heavy, iron plates, forming a pro- 
 tective sheathing for war vessels and also for certain types of land 
 fortifications, designed to withstand the penetration of projectiles. 
 Much lighter plates, sometimes less than one-quarter inch thick, 
 have recently been developed for the protection of motor cars, 
 railway trains, etc. At first it was made of cast iron, or of un- 
 treated wrought iron; later, of alternate layers of steel and 
 wrought iron, cast or welded together (compound armor plate, or 
 steel-faced wrought -iron armor plate), the steel to give hardness, 
 and the wrought iron toughness. It is at present made exclu- 
 sively of steel (usually special steel), one face of which is car- 
 burized (by heating in contact with carbonaceous matter at a high 
 temperature) and hardened to a depth of about an inch, the car- 
 burizing effect decreasing with the depth below the surface, the rest 
 of the plate being comparatively soft (low in carbon) and tough; 
 this is called face-hardened armor plate or cemented armor plate. 
 The De Marre formula gives the striking velocity necessary to 
 effect complete penetration of homogeneous nickel steel (not 
 carburized on one face but of uniform composition and structure 
 throughout); it is as follows: 
 
 T _ , , 0.75^ X 0.70 
 V = (3.00945) -^- 
 
 V = striking velocity in foot pounds; 
 d = caliber of gun in inches; 
 e = thickness of plate in inches; 
 p weight of projectile in pounds. 
 
 A correction of the velocity thus calculated must be made, 
 depending upon the size of gun and thickness or type of plate. 
 The penetration of a given projectile, with corresponding resist- 
 ance offered by the plate, based on this formula, is known as the 
 figure of merit. 
 
 The Beardmore process consists in casting alternate layers of 
 hard and soft steel. This material is then rolled or forged, 
 hardened, etc. 
 
 Bessemer's process for armor plate consisted in piling alter- 
 nately plates of cast (crucible) steel on plates of puddled or scrap 
 iron which were first carefully cleaned, and then coated with a 
 very fusible flux. The pile was then welded together, etc. 
 
 The Corey reforging process consisted in forging nearly to 
 size, then carburizing and forging down to exact size, followed by 
 hardening. 
 
 In the Demenge process for face hardening, one side of the mold 
 is lined with carbonaceous material, to be later taken up by the 
 steel, and the opposite side is formed as a chill, consisting of a 
 mass of iron through which water may be circulated. 
 
ARMOR PLATE ARRESTED PURIFICATION 9 
 
 The Ellis process for making compound armor consisted in 
 fastening a hard steel and a soft iron plate together by pouring 
 molten steel between. 
 
 Gruson's chilled cast-iron armor was made by pouring cast 
 iron in chill (iron) molds. 
 
 Thomas Hampton's process consisted in taking steel plates 
 or slabs which were piled, reheated, and rolled or hammered 
 together, then carburized on one face, and afterward rerolled, 
 if desired, and hardened. 
 
 The Harvey process consists in impregnating one face of a soft 
 steel plate, which has been rolled or forged down, with carbon by 
 heating it for a number of days at a temperature sufficient to melt 
 certain grades of cast iron (say, 1200 C.; 2192 F.) in contact with 
 carbonaceous material, after which the carburized face is hard- 
 ened by spraying it with cold water. This method of heating is 
 sometimes referred to as decremental hardening, since the carbon 
 (and with it the hardness) decreases below the carburized 
 surface. 
 
 The Krupp process is very similar to the Harvey, one patent 
 specifying heating the plate with the surface to be carburized in 
 contact with illuminating gas which deposits a layer of fine carbon 
 which is readily taken up by the steel; another has to do with 
 producing a fibrous structure by making the steel of special com- 
 position, and by heating it to a certain temperature. The prod- 
 uct is sometimes called Krupp cemented armor (K. C. armor). 
 
 The St. Chamond armor plate consists of steel containing nickel 
 and chromium in addition to carbon. 
 
 The Tressider process for hardening armor plate consists in 
 subjecting one or both faces to a spray of cold liquid supplied 
 under considerable pressure by a great number of smalt jets. 
 
 Whitworth armor plate was made of fluid compressed steel built 
 up in hexagonal sections, each of which was composed of con- 
 centric rings around a central circular disk, the object being to 
 eliminate the liability of cracking, or to restrict its area. 
 
 The Wilson process for making compound armor plate con- 
 sisted in pouring molten steel on a soft iron plate, in the ratio of 
 one-third steel to two-thirds iron. The resulting ingot was then 
 heated, rolled, and machined. This is an improvement of Cam- 
 mel's method. 
 
 See also Casting for certain other methods similar to those 
 described above. 
 
 Armored. A term sometimes used for case-hardened: see page 
 67. 
 
 Armored Glass. See Wire Glass. 
 
 Armorized. A term sometimes used for case-hardened: see 
 page 67. 
 
 Arnold's Subcarbide Theory. Of hardening: see page 280. 
 
 Arnold Test See page 482. 
 
 Arnoldite: Arnpldite Steels. See page 277. 
 
 Arrestation Point. See page 264. 
 
 Arrested Purification. Not carried to its greatest possible extent, 
 as in pig washing. 
 
io ARRHENIUS' THEORY AUTOMORPHIC CRYSTAL 
 
 Arrhenius' Theory. See page 89. 
 
 Arris. The rough edge resulting from the cold shearing of plates, 
 
 etc. 
 
 Arsenide Ore. See page 244. 
 Arsenppyrite. See page 245. 
 Artificial Steel. See page 71. 
 Ascensional Casting. See page 57. 
 
 Ash; Ashes. In its chemical sense ash is the incombustible residue 
 of a substance; ashes, and sometimes ash, is used for that portion 
 of a fuel which has not burned, but which may contain a small 
 proportion of combustible matter. 
 Asiderite. See page 291. 
 Assaying. See page 82. 
 Association. See page 84. 
 Assorting Room. See page 433. 
 Astrolitholpgy. See page 291. 
 
 Asymmetric System. Of crystallization: see page 120. 
 Ataxite. See page 292. 
 -ate.: Chemical suffix: see page 88. 
 
 Atmosphere. (i) The gaseous envelope surrounding the earth; (2) 
 the pressure of the air at the surface of the earth, generally con- 
 sidered as 14.7 pounds to the square inch, with the barometer 
 at 30" (760 millimeters) : commonly used as a unit for expressing 
 gas pressures. 
 
 Atom. See page 81. 
 
 Atom, per cent. See page 83. 
 
 Atomic Aggregate. See page 81. 
 
 Atomic Heat. See page 85. 
 
 Atomic Theory. See page 81. 
 
 Atomic Volume. See page 87. 
 
 Atomic Weight. See page 83. 
 
 Atomicity. See page 86. 
 
 Attack. Form of testing: see page 482. 
 
 Attack-polishing. See page 288. 
 
 Attrition. See page 331. 
 
 Atwood Process. See page 117. 
 
 Aubertin and Boblique Process. See page 384. 
 
 Auchy's Chemical Theory. Of iron-carbon steels: see page 278. 
 
 Austenite. See page 274. 
 
 Austenite-pearlite Inversion. See page 275. 
 
 Austenite Range. See page 275. 
 
 Austenite Steels. See page 276. 
 
 Austenitic Manganese Steel. See page 451. 
 
 Austenitic Steels. See page 445. 
 
 Austenpid. See page 275. 
 
 Austenito-martensitic Steel. See page 276. 
 
 Autoclave. See Slag Cement. 
 
 Autoelectrolysis. See page 108. 
 
 Autogenous Electrolysis. See page 108. 
 
 Autogenous Soldering, Welding. See page 505. 
 
 Autographic Recorder. In testing: see page 471. 
 
 Automorphic Crystal. See page 122. 
 
AUTOREDUCTION AXIS OF PRINCIPAL STRESS II 
 
 Autoreduction. Of certain compounds which can be reduced to the 
 
 metallic condition by the simple application of heat. 
 Avogadro's Law. See page 85. 
 Axe Temper. See Temper. 
 Axial Forces; Load. See page 332. 
 Axial Segregate. See page 56. 
 Axial Stresses. See page 332. 
 Axis. See Curve. 
 Axis of Principal Stress. See page 332. 
 
B 
 
 B. (i) Chemical symbol for boron, q.v.; (2) grade of wrought iron, 
 also of wire: see page 509. 
 
 Ba. Chemical symbol for barium: see page 84. 
 
 Be. Chemical symbol for beryllium (now called glucinium) : see 
 page 84. 
 
 Bi. Chemical symbol for bismuth; see page 84. 
 
 Br. Chemical symbol for bromine: see page 84. 
 
 B. G. (Eng.). Sheet and hoop iron standard gage. 
 
 B. H. ; B. B. H. Best hammered; best best hammered ; trade desig- 
 nations for qualities of hammered wrought iron. 
 
 B. O. H. Basic open hearth: see page 309. 
 
 B. O. V. Brown oil of vitriol: sp. gr., 1.6 to 1.74. 
 
 B. &. S. Gage. Brown & Sharpe gage: see page 188. 
 
 B. T. U. British thermal unit: see page 199. 
 
 B. W. G. Birmingham wire gage: see page 188. 
 
 Baby Bessemer Converter. See page 23. 
 
 Bacillar Structure. See page 125. 
 
 Back. Of a converter: see page 18. 
 
 Bacon and Thomas Process. See page 384. 
 
 Bailey Resistance Furnace. See page 154. 
 
 Bajault and Roche Process. See page 113. 
 
 Baked. (i) Of steel: see page 226; (2) of wire: see page 507. 
 
 Baker. For wire: see page 507. 
 
 Baker Process. See page 384. 
 
 Balanced Roll. See page 406. 
 
 Ball. (i) In puddling: see page 376; (2) in making welded tubes: 
 see page 490. 
 
 Ball Mill. A mill for grinding materials into a very fine powder, 
 consisting of a revolving cylinder in which are heavy stone or 
 iron balls. 
 
 Ball Stuff. See pages 17 and 396. 
 
 Ball Test. For hardness: see page 477. 
 
 Ball and Wingham Process. See page 384. 
 
 Ballantine Method. For determining hardness: see page 478. 
 
 Bailer. See page 21. 
 
 Balling Furnace. See page 377. 
 
 Balling -heat Processes. See page 134. 
 
 Ballistic Test. See page 482. 
 
 Balthasar Mill. See page 417. 
 
 Banal Deformation. See page 126. 
 
 Banded Structure. See page 127. 
 
 Bank. (i)A row of soaking pits having the same set of regenera- 
 tors; (2) to shut down a blast furnace temporarily by cutting off 
 .the blast: see page 37; (3) a rack or place where rolled material is 
 piled to cool (Eng.). 
 
 Bank Oven. See page 95. 
 
 Bar. See oag.e 468. 
 
BAR IRON BATHO FURNACE 13 
 
 Bar Iron. Wrought iron in the form of bars. 
 
 Bar Mill. See pages 413. 
 
 Bar Steel. See page 71. 
 
 Barba's Law. See page 473. 
 
 Barff Process; Barffed. See page 367. 
 
 Bark. Of steel: see page 226. 
 
 Bark Mill. A mill for crushing the graphite used in the manufac- 
 ture of graphite crucibles. 
 
 Barked Fracture. See page 178. 
 
 Barnett Process. See page 379- 
 
 Barrel. Of a roll: see page 403. 
 
 Barrow Charging. See page 33. 
 
 Barus Gas Pyrometer. See page 207. 
 
 Barus Thermoelectric Pyrometer. See page 208. 
 
 Basal Cleavage. See page 124. 
 
 Base. (i) In chemistry: see page 88; (2) ground mass: see page 
 125; (3) of a paint: see page 365. 
 
 Base Box. Of tin plate: see page 433. 
 
 Base Material. Of enamels: see page 370. 
 
 Base Metal. See page 84. 
 
 Base -metal Couples. See page 209. 
 
 Basic Bessemer Ore. See page 243. 
 .Basic Bessemer Pig. See page 343. 
 
 Basic Bessemer Process. See page 15. 
 
 Basic Bessemer Steel. Steel made by the basic Bessemer process. 
 
 Basic Bottom. See Lining. 
 
 Basic Clay See page 396. 
 
 Basic Converter. See page 17. 
 
 Basic Crucible Process. See page 113. 
 
 Basic Flux. See Flux. 
 
 Basic Iron. See page 343. 
 
 Basic Lining. See Lining. 
 
 Basic Material. See page 17. 
 
 Basic Open Hearth Process. See pages 309 and 315. 
 
 Basic Open Hearth Steel. Steel made by the basic open hearth 
 process. 
 
 Basic Pig Iron. See pages 343 and 346. 
 
 Basic Purifying Processes. See page 382. 
 
 Basic Refractories. See page 396. 
 
 Basic Slag. See Slag. 
 
 Basicity. See page 87. 
 
 Basin. In puddling: see page 374. 
 
 Bastard Slag. See Slag. 
 
 Bat-Stick. A stick usually a sledge handle used by a hammer- 
 man for the purpose of revolving the axle or forging on which he 
 may be working. Usually the forging is hanging in a sling, sup- 
 ported by a chain pulley. The hammerman slips his bat-stick 
 between the reins of the tongs next the jaws and uses it as a lever 
 to turn the forging after each blow of the hammer (G. Aertsen). 
 
 Batch. In making crucibles: see page 112. 
 
 Bates Process. See page 68. 
 
 Batho Furnace. See page 312. 
 
14 BATTED BENDING MOMENT 
 
 Batted. Of wire: see page 508. 
 
 Battery. See Hammer. 
 
 Battetura (Eng.). Hammer scale. 
 
 Bauernofen. See page 147. 
 
 Baumann's Method. For sulphur prints: see page 288. 
 
 Baur Method. For determining hardness: see page 480. 
 
 Bauschinger's Formula. For tensile strength: see page 337. 
 
 Bauxite ; Bauxite Brick. See page 398. 
 
 Baykoff's Method. For hot etching: see page 287. 
 
 Bead. Or blister: see page 71. 
 
 Beaded Pearlite. See page 274. 
 
 Beading. Of boiler tubes; rounding off the ends after expanding, 
 
 or the ends so rounded off. 
 Beam. Of a testng machine: see page 469. 
 Bean Ore. See page 244. 
 Bear. See Salamander. 
 
 Beardmore and Cherrie Process. See page 60. 
 Beardmore Process. See page 8. 
 Bearing Compression. See page 336. 
 
 Bearing Metal. Used for bearings : same as Anti-friction Metal. 
 Beasley Process. See page 379. 
 Beaumontague (Eng.). A compound used for filling up holes in 
 
 castings, etc., for the purpose of concealment. 
 Becquerel Effect. See page 209. 
 Becquerel Gas Pyrometer. See page 207. 
 Becquerel Optical Pyrometer. See page 207. 
 Becquerel Thermoelectric Pyrometer. See page 208. 
 Bed. (i) Layer, e.g., a bed of coal; (2) bottom of a furnace, etc. 
 Bedson Continuous Galvanizing Process. See pages 370 and 509. 
 Bedson Mill. See page 412. 
 Beehive Coke; Oven. See page 95. 
 Beetle. Or maul: a heavy wooden mallet. 
 Behrens Scale. Of hardness: see page 480. 
 Beilby's Amorphous Cement; Amorphous Phase: see page 281. 
 Beilby's Hard Iron. See page 281. 
 Beilby's Theory. Of hardening: see page 281. 
 Belford Process. See page 137. 
 Belgian Mill. See page 416. 
 Bell (i) Of a blast furnace: see page 32; (2) in the manufacture 
 
 of tubes: see page 489. 
 Bell and Hopper. See page 32. 
 Bell-Krupp Pig Washing Process. See page 383. 
 Bell Process. (i) Of dephosphorizing or pig washing: See page 
 
 383; (2) for purification: see page 384. 
 Bellied (Belly) Core. See page 299. 
 Bellied (Belly) Bass. See page 405. 
 Belly. Of a converter: see page 17. 
 Belly Helve. See Hammer. 
 Belly Walls. Of a blast furnace: see page 27. 
 Belt Driven. See page 407. 
 Bench Hardened Wire. See page 508. 
 Bend (Bending) Test. See page 476. 
 Bending Moment. See page 337. 
 
BENDING RESILIENCE BESSEMER PROCESS 15 
 
 Bending Resilience. See page 331. 
 
 Bending Rolls. Heavy rolls of cast iron or steel, set in strong hous- 
 ings, and used either for the straightening of crooked plates, or- for 
 bending them into arcs of circles or into complete cylinders. 
 
 Bending Strength. See page 330. 
 
 Benedicks' Colloid Hypothesis. Of osmondite: see page 277. 
 
 Benedicks' Equilibrium Diagram. See page 271. 
 
 Benedicks' Formula. For Brinell hardness number: see page 478. 
 
 Benedicks' Reagent. See page .287 
 
 Benedicks' Theory. Of beta iron: see page 280. 
 
 Benefaction ; Beneficiation. See Ore. 
 
 Benmutic. See page 270. 
 
 Benmutic Steel. See page 273. 
 
 Berard Process. See page 317. 
 
 Bernardos Process. See page 503. 
 
 Berner Process. See page 137. 
 
 Berthelot Calorimeter. See page 201. 
 
 Bertrand Process. See page 368. 
 
 Bertrand-Thiel Process. See page 315. 
 
 Bessemer Ferro -silicon. See page 354. 
 
 Bessemer Iron; Metal; Pig. See page 343. 
 
 Bessemer Ore. See page 243. 
 
 Bessemer (Anthony) Process. Consisted in exposing molten pig 
 iron to the action of air, steam, or even pureoxygen in a cylindrical, 
 revolving reverberatory furnace. 
 
 Bessemer (Henry) Process. (i) For armor plate: see page 8; (2) 
 for fluid compression: see page 63; (3) for making continuous 
 sheets: see page 65. 
 
 Bessemer Process. For making steel, sometimes called converting 
 process and, rarely, air refining process or pneumatic process : A 
 process for the production of steel consisting in blowing air 
 through molten pig iron contained in a suitable vessel, whereby 
 the impurities are oxidized and removed, and the product is 
 obtained in a fluid condition. Depending upon the nature of 
 the lining of the vessel, there are two modifications: (a) acid 
 Bessemer process (the original process, hence also called simply 
 Bessemer process) by which nearly all the silicon, carbon, and 
 manganese are eliminated; and (b) basic Bessemer process (due 
 to Thomas, aided to some extent by Gilchrist, and sometimes 
 called Thomas-Gilchrist process or, on the Continent, Thomas 
 process) in which there is elimination of nearly all the silicon, 
 carbon, and manganese, as in the acid process, and, in addition, 
 most of the phosphorus and part .of the sulphur. 
 
 The vessel or converter is usually pear- or egg-shaped, the 
 bottom (rarely one side) of which is perforated with a large number 
 of holes through which a powerful blast of air enters and passes 
 through the bath of metal, thereby oxidizing the impurities which 
 go into the slag if solid, or out of the mouth of the converter 
 if gaseous. After the oxidation of the impurities, the bath 
 contains a certain amount of oxide and free oxygen which are 
 removed by manganese in some form with or without extra 
 carbon. 
 
i6 
 
 BESSEMER PROCESS 
 
 The equipment of a modern plant consists (in this country) 
 essentially of usually two to four converters, provided with cranes 
 and other appliances for pouring in the molten pig and handling 
 the finished steel, etc. ; cupolas for melting the pig (direct metal 
 from the blast furnace, with th,e intervention of mixers, is now 
 
 FIG. i. Converter in action. 
 
 generally used), and spiegel if rail steel is to be made; blowing 
 engines (in a separate building) for supplying the blast. The 
 operation of the vessels is controlled by a blower stationed on 
 a platform (pulpit) situated at a little distance so he can see all 
 that is going on. There are also pouring platforms, yards, etc. 
 The converter is lined with either acid or basic material (aeid 
 
BESSEMER PROCESS 17 
 
 converter, basic converter) depending upon the practice, and is 
 mounted at about the middle on trunnions so it can be tilted to 
 various angles (tilting converter, tipping converter). In the 
 original form it was set on a permanent foundation and could not 
 tip (fixed converter, stationary converter), this type being still 
 employed in Sweden (Swedish fixed converter). The vessel 
 consists of a steel shell suitably lined, and comprises three sec- 
 tions : the bottom, the middle part or body (belly), and the upper 
 part or nose which is open at the top or mouth. The blast, at a 
 pressure of about 20 to 25 pounds to the square inch, is admitted 
 at the bottom through tuyeres or holes formed in bricks of a special 
 design, called tuyere bricks (each of which contains a number of 
 holes), around which is rammed refractory material (bottom stuff), 
 the whole being held in a suitable casting. As the lining of the bot- 
 tom wears away much more rapidly than that of the vessel proper, 
 A. L. Holley designed one which could be readily detached and 
 replaced by a fresh one (Holley movable or removable bottom). 
 A modification of this, where the blast connections do not need 
 to be broken, the bottom being simply slid out of a frame, is 
 termed a draw bottom. The bottom is closed by an iron plate 
 (bottom plate), between which and the bottom of the tuyeres is an 
 open space (wind box, blast box, air box, or tuyere box) into 
 which the blast is admitted. For basic practice the tuyere holes 
 are usually formed by ramming lime around pins which are sub- 
 sequently withdrawn, this forming what is called the plug; a bot- 
 tom made in this way is sometimes termed a pin bottom. For 
 acid vessels the body and nose sections are lined with blocks or 
 pieces of ganister or firestone set in ball stuff (a mixture of ground 
 ganister or quartz and sand with a little clay to make the mass 
 plastic). For basic practice crushed burnt dolomite mixed with 
 tar or pitch (basic material) is rammed in. The bottoms and 
 basic lining must be dried very carefully before use. In acid 
 practice the bottoms last about 23 to 25, occasionally up to 30, 
 heats, and the vessel linings up to five or six thousand or more; in 
 basic practice the bottoms last about 20 to 40, and the vessel 
 linings 100 to 200 heats. While the vessel is in service it is 
 patched between heats, and more thoroughly on Saturday nights, 
 by throwing on the worn spots ball stuff or vessel patching, and 
 at the same time any accretions (kidneys) are pried off. If one 
 of the tuyeres burns through, the vessel may be turned down while 
 the charge is still in it, and the defective tuyere either cut out and 
 a fresh one put in its place, a dummy tuyere (without any holes in 
 it) inserted, or else it may be noodled, i.e., strips (noodles or rat 
 tails) of ball stuff forced into the holes, and an iron plate clamped 
 on over the bottom, and in this last case it is called a blind 
 tuyere. 
 
 The vessel may have one of two forms, eccentric or concentric. 
 In the former case one side of the nose is straight while the other 
 is curved, thus bringing the center of the mouth to one side of the 
 vertical axis; in the latter case the taper or curve of the nose is uni- 
 form all the way around, which brings the mouth directly in the 
 center. When a vessel is tipped on its side (turned down) there 
 2 
 
i8 
 
 BESSEMER PROCESS 
 
 must be enough curve or belly to permit the iron to lie below the 
 level of the tuyeres. In the eccentric converter, for given cubical 
 contents, the belly is greater. With this type the converter is 
 tilted to the same side to receive the molten pig and also to dis- 
 charge the blown metal (pig iron purified by blowing air through 
 it). The concentric co verter is turned down on one side (iron side) 
 to receive the pig, and on the other side (steel side) to discharge 
 the blown metal. In the eccentric converter the side of greatest 
 
 Bolts for fattening shell 
 r /Vo Trunnion King 
 
 FIG. 2. Elevation of converter. 
 (Harbord and Hall, "Metallurgy of Steel".) 
 
 curvature is called the belly; the part of this side next the bottom, 
 the shoulder; the middle of the smaller side, the back; and the 
 upper part of that side next the nose, the breast. 
 
 As already stated, in the ordinary type of converter, the air is 
 introduced through the bottom, and this is termed a bottom blown 
 converter. Practically only in the case of baby Bessemer con- 
 verters, the air may be introduced through tuyeres or holes in the 
 side for the purpose of reducing the necessary pressure of blast: 
 this is known as a side blown converter. In some of the earlier 
 types of converter attempts were made to introduce the blast 
 through a pipe thrust down nearly to the bottom of the bath, and 
 
BESSEMER PROCESS 
 
 this was called an internally blown converter. One form of tuy- 
 ere for this purpose, termed a built up tuyere, consisted of an iron 
 tube continued down and attached to the tuyere proper; it was 
 
 Upper Part of Shell or 
 Nose Section 
 
 FIG. 3. Section of concentric converter. 
 (Harbord and Hall, "Metallurgy of Steel".) 
 
 protected by hollow circular bricks similar to the sleeve bricks 
 used for covering the stopper rod of a ladle. A process devised 
 by Davy consisted in using an ordinary ladle covered with a lid 
 
20 i BESSEMER PROCESS 
 
 through which a tuyere passed nearly to the bottom of the ladle. 
 One style of internally blown converter, called a tank converter, 
 was a lined iron tank with usually three compartments, the divid- 
 ing walls of which did not extend quite to the bottom, but all the 
 way to the top. When air was blown into the two outside com- 
 partments, it passed down under the partitions and up through 
 the metal in the middle compartment. 
 
 Acid Bessemer Process. The vessel heated from the previous 
 charge, or by building a fire within, is turned down on its side and 
 the molten pig iron run in where it rests in the belly below the 
 tuyeres. The blast is then turned on and the vessel turned up, 
 i.e., rotated to the vertical position. The changes taking place 
 are indicated by the character of the flame : at first it is very short 
 and dull, only the silicon and part of the manganese burning; 
 after the silicon is gone the carbon is attacked, and the flame 
 grows longer and very brilliant, and the flame is said to break 
 
 Back 
 
 Shoulder 
 
 Belly 
 FIG. 4. Converter parts. 
 
 through. This latter period is sometimes called the boil on 
 account of the copious evolution of carbonic oxide gas which vio- 
 lently stirs up the charge. As the flame, is very trying to the 
 eyes, special dark colored glasses (blowers' glasses) are employed 
 to observe it. When the carbon is practically all gone the flame 
 drops (drop of the flame), which is an indication that the process 
 is finished. The heat necessary is derived principally from the 
 combustion of the silicon and carbon. If the pig iron employed 
 contains too high a percentage of silicon (hot iron or hot blowing 
 iron) too muchheat will be generated, and the charge is said to 
 blow hot (too hot). In this case it is necessary to cool the bath 
 by blowing in a little steam with the blast or, better, by throwing 
 in steel scrap (scrapping). If, on the other hand, the iron con- 
 tains too low a percentage of silicon (cold iron or cold blowing 
 iron), the reverse action results, and the charge is said to blow 
 cold. The necessary additions for deoxidizing the steel and giv- 
 ing it the right composition may be made in the vessel, or more 
 usually in the ladle (see Recarburization) . Metal which has been 
 blown too long (overblown) is overoxidized, and hence inclined 
 to be wild. The charge is said to have been blown full when prac- 
 
BESSEMER PROCESS 21 
 
 tically all the carbon has been removed. If the blowing is stopped 
 shortly before this point is reached, the metal is said to be blown 
 young (rarely termed a hard blow) . Slopping is where the metal 
 surges around so violently that some of it is thrown out. For 
 the method of handling and pouring the steel, see page 57. In 
 this country a heat takes from about 8 to 15 minutes, and the 
 capacity of the vessels varies from about 8 to 20 tons per heat, the 
 output for a pair of vessels being about 40,000 to 65,000 tons 
 per month. 
 
 Basic Bessemer Process. A certain amount of lime is charged 
 with the iron, and the process is conducted in practically the 
 same way as the acid until the flame drops. Here, instead of 
 turning the vessel down, the blowing is continued (sometimes a 
 little more lime is added) for about four to five minutes, during 
 which time the phosphorus and some of the sulphur are removed. 
 The end of the operation is determined by taking a test ingot 
 which is forged down, quenched in water, and broken; the frac- 
 ture and also the malleability indicate the state of the process. 
 The period before the drop of the flame is called the fore blow, the 
 latter one the after blow (rarely over blow). When ready, the 
 vessel is turned down, as much as possible of the slag poured off, 
 and the metal recarburized in the vessel or in the ladle. As a 
 small percentage of phosphorus always passes back into the metal 
 from the slag, the heat must be blown down, i.e., the phosphorus 
 reduced to a lower percentage than that required in the steel. A 
 heat takes about 20 to 25 minutes, and one vessel can produce 
 about looo to 5000 tons per month, depending on the size, which 
 varies from about 15 to 25 tons. 
 
 For the composition of pig iron required for the two processes, 
 see pages 344 and 346. 
 
 Modifications of the Bessemer process have been concerned 
 almost entirely with basic practice, as will be seen below. 
 
 The Champin pneumatic process was a modification for making 
 wrought iron of which the advantages would. appear to be very 
 doubtful. Pig iron was blown in a converter in the usual way, 
 and the blown metal was then distributed, by means of a ladle, 
 into heated revolving cylinders, called bailers, and when it had 
 solidified in balls, it was taken to a squeezer (see page 377), 
 afterward given a wash heat, and then worked down as usual 
 into the desired product. 
 
 Flohr adds (basic process) briquets of iron ore, scale, etc., 
 bound together with about 10% of slaked lime, and claims that 
 thereby the slag is made thinner, and the dephosphorization 
 much more rapid. 
 
 Harmet's process (basic) consists in treating the molten pig,* 
 first in an acid vessel to eliminate the silicon, and then in a basic 
 vessel to remove the phosphorus and the remainingi mpurities, 
 care being taken that none of the silicious slag from the first 
 vessel goes into the second; this is also termed repouring process, 
 or transfer process. 
 
 The object of George Lauder's Process was to leave the 
 desired amount of carbon in the bath at the end of the blow; 
 
22 BESSEMER PROCESS 
 
 this was to be secured by first blowing and decarbunzing only a 
 portion of the charge, trjte remainder being added and blown only 
 sufficiently to oxidize the silicon; the necessary amount of man- 
 ganese was added as usual. 
 
 ^ The Massenez modification of the basic process for treating 
 high silicon metal consists in charging only part of the lime at the 
 commencement of the process, and when the carbon flame appears 
 (showing the silicon has been eliminated) as much as possible of 
 the slag is poured off; the balance of the lime is then added, and 
 the blowing completed. 
 
 In Pettitt's process (basic) iron oxide was used to effect the 
 removal of the phosphorus, irrespective of the lining of the 
 converter. 
 
 Rochussen and Daelen's process consisted in charging rich 
 iron ore into the converter (acid) with the molten pig, and in 
 lining the converter with it previous to the blow. The claim 
 was made that the amount of blast required was largely dimin- 
 ished while the amount of steel was increased, but the excessive 
 corrosion which must take place would more than offset any 
 such advantages. 
 
 Schiebler's process (basic) consists in charging the metal and 
 part of the lime in the vessel, and both the metal and slag are 
 poured out when the first or phosphatic slag is formed. The 
 treatment is completed in a reverberatory furnace having a basic 
 or a neutral hearth, with the addition of the balance of lime or 
 flux. 
 
 Stock Converter Process. "This is a combination of an oil- 
 melting furnace and small side-blown converter which has lately 
 been erected at the Darlington Forge, and is said to be giving very 
 good results. Materials are charged cold into the previously 
 heated converter; oil fuel under a pressure of about 40 pounds to 
 the square inch is supplied through flexible tubing to small tubes 
 about ^{2 of an inch in diameter, let into the main blast tuyeres, 
 which are about 2 inches in diameter, and air for combustion, at a 
 pressure of about i% pounds, is admitted. When the charge is 
 melted, which takes about i^ hours for a 3-ton charge, the con- 
 verter is rotated to the blowing position, the oil shut off, and the 
 bath of metal subjected to a blast of air on the surface for about 
 1 6 to 19 minutes, when the vessel is rotated into the teeming posi- 
 tion and finishing metal added in the usual way. The waste 
 gases pass through an economizer which, when the converter is in 
 the blowing position, is opposite the mouth of the converter, and 
 this economizer contains the blast pipes through which the blast 
 passes on its way to the converter, and in passing through which, 
 it is heated up to a temperature of about 800 F. Owing to the 
 intense heat developed during melting and blowing with heated 
 blast, the converter has to be lined with magnesite bricks, but low 
 phosphoric iron is used and no attempt is made to dephosphorize. 
 The advantages of this converter are that no impurities are taken 
 up by the pig iron during melting, as in case of coke melting in 
 cupolas, and owing to the hot blast being used a very high tem- 
 perature is obtained, insuring a very fluid metal, which makes the 
 
BESSEMER PROCESS 23 
 
 process particularly applicable for manufacture of steel castings, 
 The vessel is mounted so that it can be rotated into the different 
 positions for charging, blowing, and teeming" (F. W. Harbord 
 in Harbord & Hall's "The Metallurgy of Steel," Vol. I, p. 78). 
 
 In the Swedish process the practice consists in taking the 
 metal direct from the blast furnace without any intermediate 
 mixer, and stopping blowing when the carbon has been reduced 
 to the desired percentage, which is determined by the appearance 
 of the sparks and the flame, and also by taking tests; a fixed con- 
 verter is used (Swedish fixed converter). 
 
 Walrand's method for reducing the length of the after blow in 
 the basic process was to add fluorspar with the lime to make the 
 slag fusible early in the process. Although the time for the 
 after blow was reduced, it was found that skulls were more likely 
 to be formed. 
 
 In Walrand and Delattre's modification of the basic process, 
 the metal, after being partially blown in an acid vessel, was run 
 into a ladle intended to retain the silicious slag, and was then 
 poured into a basic vessel where the blowing was completed. 
 
 Walrand and Legenisel's process, designed for use in baby 
 Bessemer converters, consisted in the addition of ferro-silicon to 
 the charge after a preliminary blow, to have the steel hot enough 
 for making small and intricate castings. 
 
 In Warner's process (basic) iron ore, containing too much phos- 
 phorus for the acid, and too little for the basic process, is smelted 
 with the addition of basic slag or phosphoric material to yield 
 basic Bessemer pig. This is first desiliconized in one converter 
 with soda ash and limestone, and then taken to a second, and 
 finished as usual. 
 
 Ordinary converters vary from about 5 to 25 tons capacity per 
 heat; for making castings, smaller sizes are generally employed, 
 up to about 5 tons, and are called baby Bessemer converters ; 
 only in contradistinction to these, the ordinary sized ones are 
 termed large or big Bessemer converters. Various modifica- 
 tions of converters, as mentioned below, have been made from 
 time to time, but principally of a mechanical nature. Sir Hfenry 
 Bessemer covered the ground so completely that a radical depar- 
 ture seems impossible. 
 
 In the Cambier converter, which is of small size, the blast 
 enters at the side, not through tuyeres, but through holes in the 
 lining which are inclined downward at a slight angle. 
 
 The Clapp-Griffith converter is essentially a small, high, side- 
 blown, stationary vessel, with a spout or slag hole at such a level 
 that the slag runs out of it during the boil. This feature appears 
 to be the only real novelty. 
 
 The Davy portable converter was a small converter of the usual 
 type, but was so constructed that, after the charge had been 
 blown and made ready for casting, it could be carried to the molds 
 and the metal poured directly into them without the intervention 
 of a ladle. 
 
 Deighton's method of operating was to have at least two spare 
 vessels, one of which would always be ready to replace a vessel 
 
24 BESSEMER PROCESS 
 
 requiring relining, so the only lost time would be that necessary 
 for changing. 
 
 In Eldred's converter the air pipe to the blowing engine is con- 
 nected with an auxiliary furnace in such a way that either pure 
 air or part air and part waste gases can be used for blowing the 
 charge, the object being to control the temperature of the charge 
 and prevent it from getting too hot. 
 
 The Hatton converter was claimed to be an improvement of the_ 
 Clapp- Griffith, having a movable bottom, and regulating valves" 
 for the blast; it also lacked the slag spout or hole. 
 
 Laureau's converter was a small, tilting, side-blown converter, 
 with the tuyeres placed high, and set in a separate ring which 
 could be easily removed and replaced, as the lining in the neigh- 
 borhood of the tuyeres is worn away most rapidly. 
 
 In the form devised by T. Levaz, the converter, which is of 
 small size, and tilting, with side blast, has the upper part 
 enlarged to form a pocket to receive the metal when the vessel is 
 turned down. Murdock's converter has essentially the same 
 feature. 
 
 The Paxsbn-Deemer converter is a small, tilting, side-blowing 
 vessel, the tuyeres being placed at the level of the metal so the . 
 blast strikes it partly above and partly below the surface. 
 
 Raapke's converter is of small size and of the fixed type, with 
 tuyeres on one side and tapping hole on the other. Oxygen is 
 added to the blast, and means are employed for utilizing the heat 
 evolved for heating the blast and for preparing the oxygen. 
 
 The Robert converter has a D-shaped cross-section with hori- 
 zontal tuyeres, slightly inclined to the radial, on the flat side only, 
 giving the bath a whirling motion; it is of small size and is tipping. 
 The original form was circular, and was called the Walrand con- 
 verter, later modified, the Walrand-Delattre, this being further 
 modified by Robert to the form described. 
 
 In Sherk and Rutter's converter, which is tilting, there are a 
 number of tuyeres so placed that only a small portion of the 
 blast enters below the surface of the metal, and by tilting the con- 
 verter the proportion may be modified. 
 
 In the Stoughtpn or long tuyere type, which is a side-blown con- 
 verter of small size, the tuyeres are on one side, discharging the 
 blast immediately at the surface of the metal. The lining on the 
 tuyere side is thicker than elsewhere, which serves to increase the 
 time the vessel can remain in service without relining, and also 
 insures better direction of the blast. 
 
 Thomas' converter was similar to a stationary converter in 
 form, but was mounted on rockers so it could be inclined with 
 less costly mechanism than that required by the regular tilting 
 type. 
 
 The Tropenas process employs a small, tilting, side-blown 
 converter with two rows of tuyeres on one side. The lower set 
 directs the blast on the surface of the metal, and the upper set 
 (called tuyeres of combustion) supply air for burning the car- 
 bon monoxide to carbon dioxide, thereby getting a greater heat 
 efficiency. 
 

 BESSEMER STEEL BILLET TEST 25 
 
 The Wills converter is a small side-blown vessel consisting of 
 two sections, a ladle section and a dome section; the tuyeres are 
 arranged to give the metal a rotary motion. The metal may be 
 tapped (a) out of a hole at the bottom of the ladle section, (b) 
 through the nose by turning the converter down, or (c) the ladle 
 section can be removed, and the metal poured directly from this 
 into the molds. 
 
 The Witherow converter is very similar to Hatton's, but 
 claimed to be simpler as regards the controlling mechanism for the 
 blast. 
 
 Wittnufftt's converter was an early type of fixed converter 
 with tuyeres on each side inclined downward. 
 
 The Zenzes converter is a small, tilting, side-blown converter 
 varying only in slight details from others of this type. 
 Bessemer Steel. Steel made by the Bessemer process. 
 Besson. "Iron of Bessemer:" name suggested for iron or low- 
 carbon steel produced by the Bessemer (pneumatic) process. 
 Best or B. A brand of wrought iron plate or bar equivalent to No. 3 
 quality, or that grade which is just superior to the commonest. 
 It is obtained by piling, reheating, and rerolling either No. i and 
 No. 2 iron, or all No. 3 brands. The best plates of the first-class 
 houses are, however, equal to the best, best best, and treble best 
 of other firms (Horner). 
 Best Best or B. B. A brand of wrought iron plate or bar indicating 
 a superior quality obtained by piling, reheating, and rerolling best 
 or No. 3 bars (Horner). 
 
 Best Best Best or B. B. B., or Treble Best. A brand of wrought 
 iron plate or bar indicating the best quality of iron made. It is 
 obtained by repiling, reheating, and rerolling the best best qual- 
 ity (Horner). 
 
 ! Best Bar. See page 378. 
 ' Best Charcoal Iron. Wrought iron made by some charcoal-hearth 
 
 process. 
 
 Best Tap (Eng.). See page 376. 
 Beta I; Beta II. See page 280. 
 > Beta (j8) Iron. See pages 264 and 272. 
 Beta Iron Theory; Beta Theory. Of hardening: see page 279. 
 ! Beton (French). Concrete beton arme, reinforced concrete. 
 } Betty (Eng.). A crowbar, 
 | Bibasic. See page 87. 
 i Bickley Mill. See page 417. 
 ! Biedermann and Harvey Process. See page 317. 
 Big Bessemer Converter. See page 23. 
 i Billet. See page 411. 
 
 i Billet Chute. A chute or inclined bin for loading billets on 
 cars, and generally operated in connection with a billet 
 conveyor. 
 
 Billet Conveyor. A device for handling billets, usually consisting 
 of an endless chain of small rollers passing around and driven by 
 drums. 
 
 Billet Mill. See page 411. 
 Billet Test. See page 483. 
 
26 BILLETING ROLLS BLANK 
 
 Billeting Rolls/ See page 411. 
 
 Billing Process. (i) Of casting: see page 60; (2) for fluid compres- 
 sion: see page 63. 
 
 Bimetallic Thermometer. See page 205. 
 
 Bimetallic Wire. See page 509. 
 
 Binary Alloy. See Alloy. 
 
 Binary Compound. See page 88. 
 
 Binary Theory. See page 89. 
 
 Binding Coal. See Coal. 
 
 Binding Material. A material used to bind (usually) refractory 
 substances together; (i) by combining with them, as a small per- 
 centage of lime in silica bricks, (2) by being more fusible, as clay 
 in sand, and (3) carbonaceous compounds which lose their volatile 
 matter on heating, such as sugar, flour, oil, etc. 
 
 Bink Process. See page 71. 
 
 Binocular Microscope. See page 285. 
 
 Bird's Mouth Weld. See page 502. 
 
 Birmingham Wire Gage. See page 188. 
 
 Bismuth.r Bi; at. wt., 208.5; rnelt. pt., 268.3 C. (515 F.) sp.gr., 
 9.75. A white metal with a faint reddish tinge. Usually occurs 
 in the uncombined condition. It is not of importance in the 
 manufacture of steel, and appears to act much like antimony. 
 
 Bite. Of rolls: see page 407. 
 
 Bituminous Coal ; Shale. See Coal. 
 
 Black Annealing. See page 431. 
 
 Black Band. A kind of iron ore: see page 244. 
 
 Black Body; Black Body Temperature. See page 207. 
 
 Black Center. See page 178. 
 
 Black Clay. See page 302. 
 
 Black Edged Plate. See page 432. 
 
 Black Fracture/ See page 178. 
 
 Black-heart Castings; Malleable. See page 258. 
 
 Black Heat; Hot. Color temperature: see page 210. 
 
 Black Iron Objects. See page 364. 
 
 Black Iron Sand. See page 244. 
 
 Black Japan. See page 365. 
 
 Black Loam. See page 301. 
 
 Black Oxide (rare). Oxide (of iron). 
 
 Black Patch. See page 432. 
 
 Black Pickling. See page 431. 
 
 Black Plate. See page 431. 
 
 Black-red Heat. Color temperature : seepage 210. 
 
 Black Sand. In a foundry, old sand. 
 
 Black Temperature. See page 207. 
 
 Black Wash Coating. See page 298. 
 
 Blacking ; Blacking Bag. See page 298. 
 
 Blacklead Blacking. See page 298. 
 
 Blacklead Crucible. See page in. 9 
 
 Blair ; Blair-Adams Process. See page 137. 
 
 Blank. A piece of metal prepared especially to be manufactured 
 into some particular object. 
 
BLANKET BLAST FURNACE 27 
 
 Blanket. In connection with a flame, to reduce the proportion of 
 air to make it as reducing as possible. 
 
 Blaseofen. See page 147. 
 
 Blast. The name given to air under pressure used for purposes of 
 combustion, etc., as in the blast furnace or the Bessemer con- 
 verter; in some cases for cooling purposes, as in the case of tools. 
 If preheated, it is termed hot blast or warm blast; if not pre- 
 heated, cold blast. A blast under considerable pressure is some- 
 times referred to as a cutting blast ; if weak, a soft blast. 
 
 Blast Box. See page 17. 
 
 Blast Furnace. A shaft furnace (see page 181), in its early days 
 called a high furnace, supplied with blast for producing pig iron 
 by smelting iron ores. It is continuous in operation, the solid 
 raw materials being charged at the top, and the molten pig iron 
 and slag collected at the bottom and tapped out at intervals. 
 Large furnaces are about 80 to 100 feet high; have an output up 
 to 600 or 700 (commonly 300 to 500) tons per day, and employ 
 blast at a pressure of 5 to 25 (usually lo'to 15) pounds per square 
 inch, and at a temperature of about 900 to 1400 F. (485 to 760 
 C.). The modern equipment consists essentially of the furnace 
 proper or stack ; powerful blowing engines for compressing the air 
 for the blast ; stoves for preheating the blast; appliances for charg- 
 ing the raw materials; a cast house for disposing of the molten 
 iron; and a power station. 
 
 Stack. There are three well denned divisions, usually circular 
 practically now never oval or square in section. At the bottom 
 is the hearth (well, laboratory, or crucible) of cylindrical shape; 
 above this the walls diverge, forming an inverted truncated cone, 
 called the bosh (also th name for the greatest diameter of the 
 furnace), above which the walls converge to the top (throat or 
 mouth), forming another truncated cone set upright. In a 
 furnace with saucer bosh or belly walls, the walls above the 
 bosh, instead of being straight, are slightly convex. The design 
 (lines) of a furnace depend both upon the nature of the ore and 
 the kind of product desired. For the fine, soft Mesaba ores it is 
 usual to sharpen the angle of the bosh, decrease the height of 
 the bosh, and increase the diameter of the hearth; for example, 
 where high silicon is desired in the pig, the diameter of the hearth 
 is decreased. The furnace is built of fire-brick (cold-blast fur- 
 naces are also built of stone), usually but not always incased in a 
 steel jacket extending part or all the way up. The fire-brick 
 portion is referred to as the lining. The section above the bosh 
 is supported on a mantle (mantel) ring (lintel plate) and columns. 
 Up to a certain distance from the bottom of the furnace the walls 
 are protected from corrosion by cooling plates of bronze or other 
 metal through which water circulates; sometimes water is caused 
 to flow down the outside. Within the past few years thin-lined 
 furnaces have been constructed where the thickness of the lining 
 has been greatly reduced; the lining is entirely cased in steel 
 plates and the cooling plates are continued practically up to the 
 top; the object is the better maintenance of the lines, and inci- 
 dentally to save on the cost of construction. 
 
28 BLAST FURNACE 
 
 Blast. Formerly the blast was always used cold (cold blast) 
 but this practice is now restricted to a few small furnaces as a 
 rule employing charcoal for fuel. Hot blast was introduced by 
 Neilson about 1828 and effected a great economy in fuel. The 
 blast temperature varies from about 900 to 1200 F. (480 to 
 
 FIG. 5. Blast furnace and hot blast stoves. 
 
 650 C.) in this country, and up to about 1600 or even 1800 F. 
 (870; 980 C.) in some European practice. The average tem- 
 perature carried on furnaces burdened with Mesaba ore seldom 
 exceeds 1100 F. (595 C.), ranging far lower than that commonly 
 applied in European practice and lower also than on most of our 
 
BLAST FURNACE 
 
 29 
 
 eastern furnaces using mag- 
 netic ores, due to the 
 Mesaba ores being more 
 easily reducible (Brassert). 
 
 Dry Blast. The practical 
 application of this to blast 
 furnace work is compara- 
 tively recent and is due 
 primarily to the Gayley 
 process which will be de- 
 scribed later, after consider- 
 ing the general conditions 
 involved. 
 
 The blast does not consist 
 solely of oxygen and nitro- 
 gen, but contains, in addi- 
 tion to these elements, vary- 
 ing amounts of moisture 
 (among other substances) 
 depending upon the temper- 
 ature and the degree of 
 liumidity of the air. The 
 amount of moisture per 
 cubic foot of air (at atmo- 
 spheric pressure) will vary 
 from less than i grain in 
 winter to over 8 grains in 
 summer, and while even this 
 latter amount might, at 
 first glance, seem inconsid- 
 erable, a brief consideration 
 of the volume of air passing 
 through a modern furnace 
 will show that this is far 
 from being the case. "With 
 air containing i grain of 
 water per cubic foot, there 
 is passed into the furnace, 
 for each 1000 cubic feet 
 used per minute, practically 
 i gallon of water per hour. 
 A furnace of average size in 
 the Pittsburgh district con- 
 sumes about 40,000 cubic 
 feet of air per minute, which 
 would pass into the furnace 
 40 gallons of water per hour 
 for each grain of moisture 
 contained in a cubic foot of 
 air" (Gayley). 
 
 The amount of moisture varies not only from day to day but 
 from hour to hour, and numerous investigations have shown that 
 
 PIG. 6. Section of one of the 
 Duquesne blast furnaces. 
 
30 BLAST FURNACE 
 
 the slightest change has a very marked effect upon the working 
 of the furnace. The amount of moisture from the air, while small 
 as compared with that contained in the materials charged in the 
 top, has a more noticeable effect for the reason that, entering at 
 the tuyeres, it is immediately decomposed by the incandescent 
 coke into carbon monoxide and hydrogen, a reaction which 
 absorbs a large amount of heat, while the moisture contained in 
 the materials charged in the top is simply evaporated and driven 
 off with the hot gases near the top of the furnace. 
 
 It has been observed that, as a rule, furnaces worked better in 
 winter than in summer, and the reason this difference has not 
 been more marked would seem to be on account of the variation 
 in the percentage of moisture in the air. The aim of the process is 
 not alone to remove as much of the moisture as possible, but also 
 to render the percentage constant, and with it the working of the 
 furnace. 
 
 Various methods for the drying (desiccation) of air have been 
 suggested and employed. These may be divided into those 
 which make use of some absorbent substance, such as calcium 
 chloride and sulphuric acid, and those which are based on extract- 
 ing the moisture by refrigeration. In connection with the use of 
 calcium chloride it should be noted that before complete expul- 
 sion of the combined water there exists what is known as the 
 tardy hydrate with less than one molecule of H 2 O; this is removed 
 only by igneous fusion, and in view of the added cost no advan- 
 tage is gained. One of the first records is that of a patent granted to 
 Mushet in 1879 for the use of calcium chloride, etc. The Fryer 
 process consists in passing the air over broken pieces of fused 
 calcium chloride, which is subsequently regenerated partly in 
 special boilers and then by fusion. In the Cremer process the 
 air is passed (either by suction or under pressure) through a 
 chamber with shelves bearing calcium chloride, sulphuric acid, 
 etc. Regeneration was effected without removal of the drying 
 agents by subjecting them to a current of hot air or waste gases 
 by means of a false bottom in the shelves. The Eisner process 
 employs calcium chloride and is carried out by means of two 
 drums: An upper drum in which the desiccation of the air is 
 effected and a lower in which the calcium chloride is regenerated. 
 Harbord employs various porous substances such as peat or 
 pumice stone to hold a concentrated solution of calcium chloride 
 which is regenerated in place. 
 
 Gayley Dry Blast Process. The apparatus consists of a refrig- 
 erating chamber in which are coils of pipe through which brine, 
 cooled to a temperature below the freezing point of water by an 
 ammonia refrigerating machine, is passed. The air circulates 
 around these pipes and deposits on them its moisture as snow or 
 ice. When the deposit becomes too thick (about every three 
 days) it is melted off by passing heated brine through the pipes. 
 The desiccated (cooled) air is then introduced into the blowing 
 engines and goes thence, in the usual manner, through the stoves 
 and into the furnace. 
 Dry blast was first tried with Isabella Furnace No. i of the 
 
BLAST FURNACE 31 
 
 Carnegie Steel Company, on August n, 1904. The dry blast 
 was not introduced all at once, but at first only one-third was 
 used. At the same time the burden was gradually increased 
 until, at the end of two weeks, it had reached an increase of 
 20%. It was found that the saving in coke amounted to 
 about 400 pounds per gross ton of pig iron produced on a former 
 consumption of a little less than 2200 pounds. As the water 
 extracted from the blast amounted to about 69 pounds per ton of 
 iron, corresponding to about 80 pounds of coke, this would not 
 account for all the saving. This subject has occasioned consider- 
 able discussion by practical blast furnacemen and scientists, and 
 many and various are the explanations which have been offered 
 to account for the results obtained. That now generally recog- 
 nized as the correct solution was advanced by J. E. Johnson, Jr., 
 and is based upon a critical temperature in the furnace which 
 must be surpassed to accomplish the necessary reactions. The 
 difference between this critical temperature and that actually 
 attained marks the efficiency of the furnace. It is therefore 
 obvious that a slight increase when figured as a percentage of the 
 temperature above the critical is very much greater than when 
 figured as a percentage of the actual temperature. 
 
 Among the attendant advantages is the fact that, owing to the 
 greater density of the air as introduced into the blowing tubs, 
 fewer revolutions of the engines are required, and the decreased 
 cost from this nearly offsets that of operating the refrigerating 
 plant. Another advantage is found in the smaller percentage of 
 flue dust produced, particularly when fine ores are being used. 
 In the case of the Isabella Furnace this was reduced from 5 to 
 i %. The process is in use at a number of blast furnace plants 
 both in the United States and abroad. 
 
 In the Miles dry blast process the air, after compression, is 
 desiccated by cooling in two steps by water sprays: first by 
 ordinary river water, and second, by refrigerated water. It 
 depends on the fact that, to secure the same degree of desicca- 
 tion, the cooling need not be carried so far after compression as if 
 uncompressed. It is claimed that with blast at 10 pounds pres- 
 sure the moisture can be reduced to about 1.38 grains per cubic 
 foot of air when refrigerated water is used; and still further when 
 brine (which can be cooled to a lower temperature) is substituted. 
 The blast is introduced near the bottom of the bosh through a 
 number of pipes or tuyeres (twyers, tweers), usually 8 to 16 in 
 number, which are protected from burning by being encased in 
 water-cooled metal castings, tuyere blocks (tuyere arch cooler). 
 The opening in the furnace wall is called the tuyere arch, and the 
 space between this and the block, the breast (water breast). 
 Depending upon the point at which the cooling water is intro- 
 duced, the tuyere is said to be side-fed or bottom-fed. The 
 overhang of a tuyere is the amount it projects into the furnace 
 beyond the inner wall. The Scotch tuyere is of cast iron, with a 
 wrought-iron coil of pipe, for the cooling water, cast in the walls. 
 The Lancashire tuyere is a hollow truncated cone with double 
 walls, the cooling water flowing between them. An open spray 
 
32 BLAST FURNACE 
 
 tuyere is somewhat similar to the above, but the rear end is open 
 (open tuyere), and the walls are kept cool by jets of water from 
 perforated pipes inside. In the spreader tuyere, which is of a 
 somewhat similar type, the water is distributed over a sheet to 
 cool the upper part of the shell, a jet of water cooling the nose, 
 and the water running back over the bottom to the outlet. A 
 vacuum or exhaust tuyere is one from which the water is sucked 
 out, instead of being forced through, to lessen the leakage in the 
 furnace if the tuyere breaks. The blast from the stoves is led 
 into a large pipe (bustle pipe) surrounding the furnace and above 
 the tuyeres with which it is connected. 
 
 At a point near the top of the hearth is a hole for tapping the 
 slag (slag notch, cinder notch, flushing hole, monkey), and lower 
 down and to one side is the iron notch, metal notch or tapping 
 hole for tapping out the molten iron. In one type of furnace 
 there was a plate (guard plate) over the cinder hole with the tap- 
 ping hole in it. In modern furnaces the hearth is entirely within 
 the furnace, and is called a closed hearth, the contents being 
 tapped through a hole in the wall. This arrangement was first 
 introduced by'Liirmann, and was called a closed front (Lurmann 
 front). "It was formerly the custom to have an open fore part 
 (open front). .In front of the furnace there was an arched-over 
 opening extending from the furnace bottom to a little above the 
 level of the tuyeres; the sides and roof of this opening formed a 
 cavity known as the fore hearth. A wall of fire-brick called the 
 dam, was carried to the tuyere level; it formed the back of the fore 
 hearth, and was supported by a stone (dam stone) or cast-iron 
 dam plate ; in the dam plate was a vertical slit, which was stopped 
 with loam, and which allowed of a tapping hole being made at 
 any convenient level, while the excess of cinder ran off through a 
 semicircular cinder notch. The arch above the dam was called the 
 tymp (timp) ; it was kept in position by a tymp plate (tymp stone) 
 of cast iron, and generally cooled by running water" (Turner). In 
 Lunnann's closed front arrangement the slag was tapped through 
 a water-cooled tuyere (scoria block) situated in a water-cooled 
 cast-iron plate (scoria plate). 
 
 At the top of the furnace is the charging arrangement consist- 
 ing usually of two bells, a large one below, and a smaller one 
 above, each fitting in a hopper (bell and hopper, cup and cone), 
 and so arranged that only one is lowered at <a time, thus prevent- 
 ing the escape of gas. Various forms of ore -distributing devices 
 (distributors) have been designed to secure an even distribution 
 of the charge within the furnace; for example there may be an 
 apron either fixed (Killeen distributor) or movable (McDonald 
 distributor) between the large bell and the inwall (interior wall) 
 to deflect the descending charge. A revolving top is where the 
 chute or bell is revolved a certain amount for each addition; the 
 older form is accordingly distinguished as a stationary top. 
 
 Charging. The ore is kept in huge piles (stock pile) in a 
 yard, and is handled by large traveling cranes (ore bridge, 
 gantry crane). It is loaded into bins from which it is run into 
 small hopper-bottom cars (larry, lorry) equipped with scales for 
 
BLAST FURNACE 33 
 
 weighing it, and from these is dumped into the buckets or boxes 
 (skips) which are hoisted to the top of the furnace up an inclined 
 bridge (skip bridge), and dumped automatically on the upper 
 bell. Depending upon whether there is a single or a double track 
 (in the latter case one skip ascending while the other is descend- 
 ing) it is single or double-skip charging. The limestone is simi- 
 larly handled; the coke is measured by volume (occasionally 
 weighed), the contents of the skip representing a definite weight. 
 This method is known as skip charging. The older method, now 
 seldom employed for new furnaces, is to weigh the materials in 
 wheel-barrows which are raised to the top of the furnace by an 
 elevator (hoist, lift), and dumped around the bell by hand (bar- 
 row charging). One complete unit or charge of ore, coke, and 
 limestone is called a round. 
 
 Blast Furnace Gas. The gas is taken of! at the top of the fur- 
 nace through one or more openings connecting with a large pipe 
 (downcomer) which leads to a large chamber (dust catcher, dust 
 chamber) on the ground, where, the direction of the gas being 
 changed, most of the dust (flue dust), consisting of a mixture of 
 fine ore and coke together with a little lime, carried over mechan- 
 ically, is deposited. As a rule no water is employed (dry dust 
 catcher), but the gas, if to be used for gas engines, is later purified 
 by being led through a chamber (scrubber) where it is sprayed 
 with water and passed over moistened bricks. In such case the 
 gas from the dust catcher is known as raw or dirty gas ; after a 
 preliminary treatment, as primary gas; and after final treatment, 
 as clean gas or, in some cases, secondary gas. There are various 
 systems; dry cleaning without water, and wet cleaning or wash- 
 ing with water sprays. In the latter process, at present more 
 commonly used, the dust, collected in reservoirs as mud, is called 
 sludge or pond sludge. Compound gas was a name suggested 
 for blast furnace gas passed through a coke oven, whereby it was 
 claimed a gas was produced containing less carbon dioxide and less 
 nitrogen then when used separately. A marked increase in 
 efficiency is shown when purified gas is used for heating the stoves. 
 Part of the gas is used for heating the stoves, and part for burning 
 under boilers or in gas engines. Owing to the high percentage of 
 nitrogen the calorific power of the gas is low (85 to 100 B.T.U.). 
 Its composition is approximately: 
 
 Carbon monoxide, 
 Carbon dioxide, 
 Nitrogen, 
 Hydrogen, 
 Hydrocarbons, 
 
 24% bv volume, 
 
 12% " " 
 60% " " 
 2% " " 
 2% " " 
 
 24% by we 
 
 17% " 
 58% " 
 
 0.2% " 
 
 0.8% " 
 
 ght. 
 
 
 i 
 
 The top of the furnace may be provided with a number of counter- 
 weighted doors (explosion doors) which open automatically to 
 relieve any excessive pressure of gas within, or these may be 
 omitted (closed top) and the top designed of sufficient strength 
 to withstand this, thus preventing solid material from being 
 blown out. A door or valve which can be opened from the ground 
 3 
 
34 BLAST FURNACE 
 
 to relieve the pressure is called a bleeder. In early practice, when 
 the gas was allowed to escape the furnace had an open top, the gas 
 burning on coming in contact with the air. In this case a chim- 
 ney (tunnel head) was provided to carry it away from the charg- 
 ing hole for the protection of the workmen. 
 
 Stoves for heating the Blast. These are cylindrical in form, up 
 to 100 feet high or a little over, and consist of a steel or iron shell 
 lined with fire-bricks which form a number of flues or passages. 
 Depending upon the number and the arrangement of the flues, 
 they are known as two-pass stoves, three-pass stoves, etc. They 
 are regenerative (see page 203) in principle, gas being introduced 
 and burned at the bottom, the products of combustion going out 
 at the top, and the blast being forced through in the opposite 
 direction, the two operations not occurring at the same time. A 
 large furnace generally has four stoves, three of which are being 
 heated (on gas) while the fourth is heating the blast (on wind). 
 The earlier stoves had cast-iron pipes (pipe stove, metal stove, or 
 direct firing stove) heated externally, and through which the 
 blast passed continuously on the recuperative (see page 204) 
 principle. The pipes sometimes had the shape of the curved butt 
 of a pistol, and were then known as pistol-pipe stoves. In using 
 preheated air (hot blast), the temperature is sometimes regulated 
 by leveling, i.e., admitting a certain proportion of cold air to the 
 blast when a fresh stove is put on, and then gradually cutting it 
 down .to nothing by the time the stove is taken off. A device 
 suggested, called an equalizer, resembles a fire-brick stove, except 
 it is used continuously, the fire-brick on the inside serving to 
 absorb heat from the blast if it is too hot, and give it up again if 
 the blast is too cold, thus keeping the temperature nearly con- 
 stant. To remove the moisture in the blast, and so get greater 
 efficiency from the furnace, the blast, before going to the stoves, 
 may be passed over pipes in which iced brine is circulated, and on 
 which the moisture is deposited as ice : this constitutes the Gay- 
 ley dry blast process. 
 
 Operation. The charge, consisting of ore, coke, and lime- 
 stone (coal or charcoal rarely replace the coke), is put in at the 
 top of the furnace, at nearly regular intervals, the operation being 
 continuous. The ratio which the ore bears to the total charge is 
 known as the burden (ore burden). If this ratio is too great or 
 too small the furnace is said to t>e overburdened or underbur- 
 dened respectively. With ordinary ore, containing about 50% of 
 iron, the proportions of materials entering and leaving the fur- 
 nace, based on one ton of pig iron produced, are approximately 
 as follows, expressed in tons : 
 
 Materials entering 
 
 the furnace 
 
 Materials leaving the furnace 
 
 Ore 
 
 2 
 
 Pig iron i 
 
 Coke 
 
 j 
 
 Slag . H 
 
 
 
 Gases 6 
 
 Air 
 
 
 
 Total 
 
 
 Total 7/^ 
 
 
BLAST FURNACE 35 
 
 It will be noted that the air constitutes over one-half of all the 
 materials going into the furnace, while the escaping gases repre- 
 sent over three-quarters of the material leaving the furnace. This 
 difference is due to the fact that the oxygen, carbon and certain 
 other substances which enter the furnace as solids are converted 
 into the gaseous state by chemical reactions which they undergo. 
 The height of the materials in the furnace is maintained at a 
 constant level called the stock line. This is determined either by 
 thrusting a rod through a hole in the top by hand, or by an auto- 
 matic device (stock indicator) consisting essentially of a rod con- 
 nected to a wire which passes over a pulley and leads to a dial or 
 other device on the ground. The blast entering the furnace near 
 the bottom burns the fuel which supplies the heat as well as the 
 carbon necessary for the reduction (deoxidation) and carburiza- 
 tion of the ore, at the same time rendering it and the slag molten. 
 If, owing to improper working, the materials become pasty (gob- 
 bing up or engorgement), they may then (a) stick to the sides 
 forming a ring, (b) arch across producing a scaffold or bridge, or 
 (c) form a large mass called a skull, thereby preventing the descent 
 of the charge above, and the furnace is then said to be hanging. 
 When this obstruction gives way, allowing the superincumbent 
 mass to fall, it is called a slip. Attempts to break down (blow 
 down) the scaffold may be made by alternately decreasing and 
 increasing the pressure of the blast (jumping) or also by increas- 
 ing the temperature (coddling). To bring down a scaffold and 
 other obstructions, a torpedo (blast furnace torpedo), containing 
 an explosive, may be introduced through one of the tuyeres or 
 through a hole cut in the wall of the furnace and discharged. 
 Sometimes there seems to be too much lime on the furnace for 
 the given condition, and still it is showing a lean cinder (slag low 
 in lime) ; this is what is commonly termed not working her lime, 
 and is caused by a high fusion zone accompanied by a cold bot- 
 tom and high top heat (Imhoff). On the other hand a slip will 
 often bring down too much limestone so that it will cause the slag 
 to be infusible or pasty; this is known as a lime set. If the heat 
 generated within the furnace is not sufficient, the furnace is 
 working cold, and may result in scaffolds (cold scaffold, cold 
 hanging), which may also be occasioned by the furnace working 
 hot (too hot), called hot scaffold or hot hanging. When the 
 charge is composed of materials of such a size and nature that the 
 blast passes through them (they are said to take the blast) 
 easily; the charge is open. -On the other hand, when the blast 
 does not ascend uniformly, the condition is called blast wander- 
 ing. The action of the charge in opening up irregular openings 
 for the blast is known as channeling, a term also sometimes ap- 
 plied to the abrasive action of the charge on the furnace walls 
 giving rise to grooves or channels. If the penetration of the blast, 
 in the region of the tuyeres, is insufficient, it is likely to cause 
 pillaring, a condition where there is a pillar of cold stock extend- 
 ing up through the middle of the hearth and surrounded by an 
 annular column of activity. When a portion of the wall of the 
 furnace, above the water-cooled part, becomes unduly heated, 
 
36 BLAST FURNACE 
 
 with the danger of burning through, the furnace has a hot jacket 
 or hot spot. Depending upon the reactions taking place in 
 different regions or zones of the furnace, they are called zone of 
 heat interception, near the top; farther down, zone of carbon 
 deposition; still lower, zone of incipient fusion; then zone of 
 slag formation; and, at the tuyeres, zone of complete fusion. 
 In practice there are four important reactions which may be 
 given as follows: 
 
 (1) Oxidation of coke: 
 
 c + o = co 
 
 (2) Reduction of iron ore: 
 
 Fe x Oy + yCO = xFe + yCO 2 
 
 (3) Decomposition of CO 2 in one or more ways. e.g. : 
 
 C0 2 + C = 2CO 
 
 (4) Decomposition of CO: 
 
 2 CO = C + C0 2 - 
 
 (4) Can proceed only where the temperature lies between 400 
 and 600 C. (750 and 1110 F.) ; above 600 C. (1110 F.) it pro- 
 ceeds with great slowness (Mathesius). The heat balance of a 
 blast furnace is an analysis and statement showing the amount 
 and sources of heat entering the furnace either as sensible heat 
 in the blast, etc., or what is generated within by the combustion 
 of fuel; this must of course equal the amount of heat leaving the 
 furnace in different forms (sensible or latent) in the gases, slag 
 and iron, and by radiation through the furnace walls. 
 
 Casting. The cinder is tapped out at more frequent intervals 
 than the iron (it has been suggested to tap the iron out continu- 
 ously by a syphon-like arrangement), those before the tapping 
 of the iron being called flushes. The operation of tapping the 
 iron is usually known as casting, and the yield of iron, the cast. 
 If part of the iron does not come out readily, it is said to lie 
 back. When the hearth is nearly empty, part of the blast escapes 
 with a roaring sound, and the furnace blows. The iron is led 
 through troughs or runners to the pig beds if it is to be sand cast 
 (see page 342), or into ladles if the metal is to be used direct in the 
 molten condition (direct metal), or is to be cast into pigs in a pig 
 machine. The small amount of slag which comes out of the iron 
 notch is separated from the iron by means of a depression in the 
 main runner, near the furnace, called the skimmer, the iron here 
 flowing under a clay- washed cast-iron plate or bridge set verti- 
 cally, the slag which is much lighter being backed up and flowing 
 off at one side. The iron from the main runner is prevented from 
 entering the side runners, until desired, by shutters, which are 
 implements of cast iron washed with clay, shaped like a spade 
 with a rod cast in them for a handle, and which are thrust down 
 into the junction of the two runners. (For the method of han- 
 dling the iron and the slag, see Pig Machine and Slag Machine.) 
 The cinder notch is opened up by a pointed bar, and closed by 
 holding another bar, with an enlarged end, in the hole until the 
 cinder chills against it. The iron notch is opened by drilling out 
 
BLAST FURNACE 37 
 
 the clay with which it is closed, and finally driving in a pointed 
 bar. It is closed by slackening the blast, and then packing in 
 balls of clay, either by hand with bars, or by a machine called a 
 gun, notch gun, or blast furnace gun. This machine consists of 
 two cylinders tandem, each containing a piston on the same rod, 
 the first being actuated by steam or compressed air, and the 
 second serving to drive the balls of clay, which are thrown in at 
 a hole in the top of the cylinder. 
 
 When a furnace is started up it is said to be blown in, and 
 when it is taken out of commission it is blown out. Where the 
 operation is stopped temporarily by taking off (stopping) the 
 blast and closing up all the openings, it is banked (damped down) ; 
 
 PIG. 7. Blast furnace casting. 
 
 when operating, it is in blast. The methods employed for blow- 
 ing in a furnace may differ in certain details, but the following 
 description covers the general practice (sometimes referred to as 
 scaffolding down). A wooden scaffold is erected inside the fur- 
 nace at a height a little above the level of the tuyeres. On this is 
 piled on end one or more tiers of cordwood. The hearth is then 
 filled with coke up to about the bottom of the tuyeres, and the 
 space between this and the scaffold is filled in with thoroughly 
 dried kindling wood in order to- ignite the mass from the outside 
 through one of the tuyeres. A considerable amount of coke is 
 dumped in at the top of the furnace, the last portion being mixed 
 with some finely broken clay which, when melted, serves to warm 
 up the tapping holes. Very little ore and flux are added for some 
 time, the proportion being increased gradually until the full 
 burden is reached after a day or two. After a furnace is blown 
 
8 BLAST FURNACE 
 
 out, accretions (scars) may be found on the walls, consisting of 
 partially fused matter and pieces of coke, limestone, etc. In the 
 hearth, usually where the bottom has been worn away, may be 
 found a metallic mass, called a salamander (q.v.) or bear, which 
 consists of pig iron containing nitrocyanide of titanium, and usu- 
 ally also there is iron with less carbon and silicon than in the 
 regular pig iron. Under the superintendent, the operations are 
 conducted by a blower who has general charge of one or more 
 furnaces, the hot blastman who has charge of the stoves, and the 
 keeper who attends to tapping the furnace and getting the run- 
 ners, molds, etc., in shape. 
 
 PIG. 8. Blast furnace casting Running the molten pig iron into 
 ladles for use as direct metal. 
 
 J. E. Johnson's Process is a method of spheroidizing graphite 
 
 in cast iron. This is effected "by bessemerizing the iron at a 
 relatively low temperature, and thus removing its silicon with but 
 little removal of carbon but with important absorption of oxy- 
 gen. The graphite of the resultant produce assembles in large 
 part in relatively harmless spheroids, instead of spreading out as 
 usual into broad continuity destroying flakes. He then remelts 
 his iron, adding enough silicon to bring about the degree of graph- 
 itization desired in the castings themselves. The spheroidizing 
 tendency persists through this remelting, so that the graphite in 
 the resulting castings also is in compact masses" (Howe). 
 
BLAST FURNACE COKE BLOCK FURNACE 39 
 
 Classification of Furnaces. According to the methods of 
 operating: 
 
 I. Fuel used: 
 
 (a) Coke furnace. 
 (6) Charcoal furnace. 
 
 (c) Anthracite furnace (a certain proportion of the fuel is 
 coke). 
 
 (d) Coal furnace (Scotland only). 
 II. Blast: 
 
 (e) Hot blast furnace. 
 (/) Cold blast furnace. 
 
 III. Charging: 
 
 (g) Barrow charging (hand). 
 
 (h) Skip charging (mechanically). 
 Merchant furnaces are those whose product is for sale. 
 
 Blast Furnace Coke. See page 96. 
 
 Blast Furnace Gas. See page 33 . 
 
 Blast Furnace Gun. See page 37. 
 
 Blast Furnace Lining. See page 27. 
 
 Blast Furnace Reactions. See page 36. 
 
 Blast Furnace Slag Cement. See Slag Cement. 
 
 Blast Furnace Torpedo. See page 35. 
 
 Blast Temperature. See page 28. 
 
 Blast Wandering. See page 35. 
 
 Blau Furnace; Blauofen. See page 135. 
 
 Blazed Pig. See page 343. 
 
 Blazing off. See page 231. 
 
 Bleckley Mill. See page 417. 
 
 Bled Ingot. See page 58. 
 
 Bleeder. See page 34. 
 
 Bleeding. (i) Of ingots which have not entirely solidified, so that 
 when they are rolled or forged, the solid skin is broken and the 
 fluid portion forced out; (2) in a furnace lined with cinder, melting 
 or fluxing out a part of the lining when it becomes too thick, by 
 raising the temperature; (3) in puddling: see page 377; (4) red 
 streaks of rust on boiler scale, indicating corrosion in the metal 
 underneath. 
 
 Blending. Mixing ores to get a suitable composition. 
 
 Blind Pass. See page 405. 
 
 Blind Tuyere. See page 17. 
 
 Blister. (i) In cemented steel; see page 71; (2) suggested as a 
 shorter term for blister bar or blister steel; (3) an excrescence on 
 the surface of steel produced by a gas bubble present or found 
 beneath the surface while the metal is hot and plastic; very fine 
 blisters are called pinhead or pepper blisters. 
 
 Blister Bar, Metal, Steel. See page 71. 
 
 Block. (i) An ingot (rare); (2) the solid brick-work surrounding 
 the port of a regenerative furnace; (3) a revolving drum, slightly 
 tapered from bottom to top, for drawing wire through the die, 
 and on which it is wound: see page 508. 
 
 Block Furnace. See page 134. 
 
40 BLOCK MOVEMENT BODY IRON 
 
 Block Movement. See page 281. 
 
 Block Oven. See pages 95 and 134. 
 
 Blomary (obs.). Bloomary: see page 134. 
 
 Blood -red Heat. Temperature color: see page 210. 
 
 Bloodstone. See page 243. 
 
 Bloom. See pages 135 and 411. 
 
 Bloom Steel (Eng.). Steel rolled into blooms. 
 
 Bloomary ; Bloomery ; Bloomary Process. See page 134. 
 
 Blooming Mill; Rolls. See page 411. 
 
 Blow. (i) To force air into or through; (2) of a blast furnace: see 
 page 36; (3) of castings: see page 55. 
 
 Blow Cold. See page 20. 
 
 Blow Down. (i) In Bessemer practice: see page 21; (2) in blast 
 furnace practice: see page 35. 
 
 Blow Full; Hot. See page 20. 
 
 Blow In ; Blow Out. Of a blast furnace: see page 37. 
 
 Blow Young. See page 21. 
 
 Blower. (i) In Bessemer practice: see page 16; (2) of a blast fur- 
 nace: see page 38; (3) a defective tube: see page 492. 
 
 Blowers' Glasses. See page 20. 
 
 Blowhole. See page 55. 
 
 Blowing Engines. Those for compressing the air for the blast used 
 in blast furnaces, Bessemer converters, etc., are of two general 
 types; (a) either steam or gas-driven reciprocating engines, or 
 (6) turbine-driven rotary engines (turbo-blowers). The air is 
 sucked into and compressed in cylinders (blowing tubs), and 
 passes thence into the blast main. 
 
 Blowing Tub. See Blowing Engine 
 
 Blowing Up. See Water Gas. 
 
 Blown. Of a casting: see page 55. 
 
 Blown Metal. See page 18. 
 
 Blowy. Of a casting: see page 55. 
 
 Blue Annealing. See page 431. 
 
 Blue Billy. See page 245. 
 
 Blue Furnace; Oven. See page 135. 
 
 Blue Iron Earth. See page 244. 
 
 Blue Powder. See page 371. 
 
 Blue Short; Shortness. See pages 46 and 198. 
 
 Blue Stone. Commercial sulphate of copper. 
 
 Blue Temper. See page 230. 
 
 Blue Vitriol. Commercial sulphate of copper. 
 
 Blue Working. See Hardness. 
 
 Blueing. See page 367. 
 
 Blume. See page 147. 
 
 Bob. Tup or drop weight: see page 481. 
 
 Bod. See page 182. 
 
 Body. (i) Quality and uniformity to yield easy and proper 
 working; (2) consistency or density, as in paints, etc.: see page 
 3 6 5; (slof a converter: see page 17; (4) of a roll: see page 403. 
 
 Body Core. See page 299. 
 
 Body Force. See page 331. 
 
 Body Iron (Eng.). Of wrought iron, especially Swedish, considered 
 
BOECKER MILL BOTTOM-FED TUYERES 41 
 
 of special suitability for manufacturing into crucible steel 
 (Brearly). 
 
 Boecker Mill. See page 417. 
 
 Bog Iron Ore ; Bog Ore. See page 244. 
 
 Bogey Casting. See page 57. 
 
 Bogie ; Bogey. Same as Buggy; a flat car or wagon usually running 
 on a narrow-gage track. 
 
 Bohemian Process. See page 76. 
 
 Boil. (i) In Bessemer practice: see page 20; (2) in open hearth 
 practice: se.e page 314; (3) in puddling: see page 376. 
 
 Boiled Bar (obs.). Common puddled bar. 
 
 Boiler Compound. See page 366. 
 
 Boiling. See page 202. 
 
 Boilings. See pages 377 and 438. 
 
 Boiling Point. See page 202. 
 
 Boiling Process (obs.). Puddling Process (q.v.). 
 
 Bolometer. See page 207. 
 
 Bolting. See page 408. 
 
 Bolting-down Rolls (Eng.). See page 414. 
 
 Bond. See page 86. 
 
 Bone (Eng.). A hard streak in a piece of steel which is being rolled 
 or forged, produced by uneven heating. 
 
 Bone Ash ; Dust. See page 68. 
 
 Bone Phosphate of Iron. A material sometimes added to a blast 
 furnace charge when it is desired to increase the content of phos- 
 phorus in the pig, e.g., for certain castings. It is usually con- 
 sidered that 2.18 parts are equivalent to i part of P2O5. 
 
 Bonehill Process. See page 380. 
 
 Bontempi Process. See page 368. 
 
 Bookwalter Converter. Another name for the Robert converter: 
 see page 24. 
 
 Boot. Of a bloomary: see page 135. 
 
 Borax. See Flux. 
 
 Boreas Steel. A trade name given to an early grade of self-harden- 
 ing steel. 
 
 Borchers Furnace. See page 154. 
 
 Bordered Boundary. See page 128. 
 
 Boring Gases (Howe). Those obtained on boring cold solidified 
 metal under water. 
 
 Boron. B; at wt., n; sp. gr., amorphous, 2.45, crystalline, 2.53 to 
 2.68. Occurs combined, and is not of importance as a constituent 
 of steel: see page 453. 
 
 Boron Steels. See page 453. 
 
 Bosh. See page 27. 
 
 Bot; Bott; Bot Stick; Botting Up. See page 182. 
 
 Bottling. See page 336. 
 
 Bottom. Of a converter: see page 17. 
 
 Bottom-blown Converter. See page 18. 
 
 Bottom Board. In molding: see page 297. 
 
 Bottom Casting, See page 57. 
 
 Bottom Cut ; Discard. See Discard. 
 
 Bottom-fed Tuyeres. See page 31. 
 
42 BOTTOM PART BREAKER 
 
 Bottom Part. Of a mold: see page 297. 
 
 Bottom Plate. Of a converter: see page 17; (2) of a bloomary: 
 
 see page 135; (3) the plate on which an open-bottom mold stands, 
 
 usually called stool. 
 
 Bottom Pouring. See pages 57 and 299. 
 Bottom Pouring Ladle. See Ladle. 
 Bottom Stuff. See page 17. 
 Boucher Process. See page 166. 
 Bouiniard Process. See page 317. 
 Boullet Process. See page 71. 
 Boulton Process. See page 61. 
 Boundary Edging. See page 128. 
 Boundary Filling; Strength. See page 282. 
 Bower Process. See page 367. 
 Bower-Barff Process. See page 367. 
 Bowke (Eng.). A South Staffordshire term meaning a small wooden 
 
 box in which iron ore is hauled underground (Raymond). 
 Box. (i) An iron receptacle for holding small material, and usually 
 
 handled by a crane; (2) a charging box: see page 314; (3) the nut 
 
 or hole with female thread in a housing, through which the 
 
 screw turns. 
 
 Box Annealing. See pages 232 and 431. 
 Box Groove; Pass. See page 405. 
 Box Piling. See page 378. 
 Boydell Process. See page 73. 
 Boyle's Law. See Gas. 
 Boys Radiation Pyrometer. See page 207. 
 Brake Burns. See Crack. 
 Brake Test. See page 483. 
 Branch Core. See page 299. 
 Branding. See Marking. 
 Branning Machine. See page 432. 
 Brasque. To line with some inactive or harmless material, or one 
 
 which will not interfere with a given operation, e.g., to brasque 
 
 a clay crucible with charcoal or lampblack. 
 Brasses. (i) The boxes made of brass or bronze containing the 
 
 babbitt or other bearing metal on which the necks or journals of a 
 
 roll, etc., turn. Bushing metal is the name sometimes given to 
 
 an alloy of copper and tin (bronze) used for this purpose; (2) 
 
 pyrites in coal (Eng. and Welsh). 
 Bray Continuous Sheet Mill. See page 433. 
 Braze. See page 505. 
 Break. See Curve. 
 Break Down. (i) Of ingots, etc., to reduce the section by rolling or 
 
 forging, more particularly, the preliminary operation; (2) of 
 
 equipment which fails under load. 
 Break Out; Through. (i) Of the flame in the Bessemer process, 
 
 when the carbon begins to burn: see page 20; (2) of molten 
 
 metal which forces its way through a furnace wall. 
 Breaker. (i) A machine for breaking up the sow and pigs: see 
 
 Pig Breaker; (2) in coal mining, the building and machinery where 
 
BREAKING BRIQUETTE 43 
 
 the coal is crushed to obtain the desired size, and also where the 
 slate is picked out. 
 
 Breaking. See page 330. 
 
 Breaking-down Point. See page 334. 
 
 Breaking-down Rolls. See page 414. 
 
 Breaking-down Temperature. For ordinary tool steel: see page 
 446. 
 
 Breaking Load. See pages 336 and 471. 
 
 Breaking Spindle. See page 407. 
 
 Breaking Stress. See page 336. 
 
 Breaking-up Process. See page 75. 
 
 Breast. (i) Of a Bessemer converter: see page 18; (2) the front 
 bank of an open hearth furnace; (3) that side of the hearth of a 
 shaft furnace which contains the metal notch (Raymond). 
 
 Breast Hole; Plate. See page 182. 
 
 Breccia; Breccia Structure. See page 125. 
 
 Breeches Runner. See page 57. 
 
 Breeze. Coke breeze: see Coke. 
 
 Breeze Oven. An oven in which breeze (fine coal or coke) is 
 burned. 
 
 Breuil Test. See page 482. 
 
 Brick Kiln; Oven. See page 182. 
 
 Bridge. (i) In a blast furnace: see page 35; (2) in a reverbera- 
 tory furnace: see page 183. 
 
 Bridge Wall. See pages 183 and 375. 
 
 Bright Annealed Wire. See page 509. 
 
 Bright Blue Temper. Oxide color: see page 230. 
 
 Bright Crystalline Fracture. See page 178. 
 
 Bright Finished Wire. See page 507. 
 
 Bright Fracture. See page 178. 
 
 Brighten. Of fuel in a blast furnace, etc., which is cool (not burn- 
 ing well), to increase the temperature, as by injecting oil. 
 
 Brilliant Fracture. See page 178. 
 
 Brimstone Acid. Made by dissolving in water the fumes from 
 burning sulphur; sulphurous acid. It contains no arsenic. 
 
 Brinell's Formula. For hardness number: see page 477- 
 
 Brinell Hardness; Hardness Number. See page 477- 
 
 Brinell Meter. See page 478. 
 
 Brinell's Notation. For critical point: see page 265. 
 
 Brinell Refining Process. See page 384. 
 
 Brinell Test. For hardness: see page 477. 
 
 Brinell and Wahlberg Test. See page 482. 
 
 Bring Down. Of metal in a cupola, etc., to melt. 
 
 Bring to Nature. See page 376. 
 
 Bring Up. Or fetch up, to increase, e.g., the percentage of carbon: 
 see page 393- 
 
 Briquette; Briquetting (Briket; Briketting). A block or brick (or 
 the method of production) of a substance not of itself coherent 
 enough, and to correct which some binding material is used. 
 Fine substances such as coal, ore, etc., are cemented together by 
 fusible (caking) coal, pitch, lime, etc. After mixing, the mate- 
 rial is put in molds, usually under considerable pressure, and with 
 
44 BRIQUETTE 
 
 or without the application of heat. The briquettes are then 
 taken out, and dried, etc., as necessary. Some of the various 
 processes may be mentioned briefly as follows : 
 
 The Schumacher process "consists in mixing with flue dust a 
 small amount of liquid containing some such material as magne- 
 sium or calcium chloride in solution, then thoroughly mixing the 
 flue dust to produce as nearly a homogeneous mass as possible, 
 and finally passing it through a briquetting press capable of 
 producing high pressures up to about 6800 pounds per square 
 inch" (Clark). The Scoria process "invloves the use of granu- 
 lated blast furnace slag and lime as a binder. Magnetically 
 concentrated flue dust, thoroughly mixed with the binding 
 agents, is pressed (at approximately 1500 pounds per square inch) 
 into the form of rectangular bricks and then subjected to the 
 action of live steam for several hours" (Clark). The Grondal 
 process "consists in forming briquettes of moistened flue dust (or 
 fine ore) without any binder, piling these briquettes carefully on 
 small platform cars and running the cars into heating ovens, 
 where the briquettes are subjected to a high temperature over a 
 considerable period of time. The carbon contained in the 
 briquettes is burned out, causing a sintering action throughout 
 the briquette, which causes the formation of a firm yet porous 
 brick" (Clark). In the tunnel kiln process, as practised at one 
 plant, flue dust is first magnetically concentrated and "the con- 
 centrate is then briquetted in a press exerting a pressure of about 
 7000 pounds per square inch, and the briquettes finally treated 
 by passing them through long tunnel kilns in which they are sub- 
 jected for about 5 hours to a temperature rising to about 2400 
 F. in the hottest zone" (Clark). The Weiss process, used for 
 briquetting ore, flue dust, and also metallic borings is based on 
 the use of lime as a binder in conjunction with the formation of 
 the carbonate by the introduction of CO 2 . This gas, under pres- 
 sure is caused to penetrate the bricks, cold at the beginning and 
 warm at the end, in order to produce a firm bond of calcium car- 
 bonate. The Ronay process is also used for briquetting borings, 
 these being subjected to heavy pressure, gradually applied, to 
 squeeze put the contained air; no binder is employed. 
 
 Roasting, sintering or clinkering are resorted to for the purpose 
 of obtaining a suitable product for use in the blast furnace, etc., 
 by partially fusing the material and so obtaining it in coherent 
 form. In the Heberlein pot method, or Huntington-Heberlein 
 pot process, "flue dust is treated by first thoroughly mixing it 
 into a mass as nearly homogeneous as may be, then charging the 
 same into a large pot shaped somewhat like a Bessemer converter 
 and holding several tons of material. The material is ignited 
 from the bottpm and a draft of air forced up through from the 
 bottom. The air supports combustion of the carbon contained in 
 the mass and the ignition gradually progresses upward. The 
 result is to burn out the carbon and to sinter the contents of the 
 pot into a solid, though porous mass. When the sintering action 
 has progressed throughout the material, the pot is inverted and 
 the mass which falls out of the pot is broken into pieces small 
 
BRIQUETTED BORINGS BRITTLE 45 
 
 enough for use in the blast furnace" (Clark). The Greenawalt 
 process ' 'involves the same principle of roasting or sintering, but 
 differently arranged apparatus is used. The principal difference 
 is that the draft is down through the mass of material to be heated 
 rather than up" (Clark). In the Dwight and Lloyd process the 
 fundamental principle is the same as in other roasting processes. 
 "The essential features of this method are comprised in the form 
 of apparatus used. The draft to support combustion during the 
 sintering process is downward, but instead of carrying on the 
 action in large pots, it is carried on in a much larger number 
 of smaller pans. These pans are joined end to end to form 
 a continuous conveyor" (Clark). The rotary kiln process 
 "which may be termed sintering, but which perhaps is more 
 clearly expressed as nodulizing or clinkering, consists in treatment 
 of flue dust (or ore) in a rotary kiln similar to that used in the 
 cement industry for the burning of cement clinker. Flue dust 
 without preliminary treatment is charged into the upper end 
 of an inclined kiln in which a high temperature is maintained by 
 the combustion of fuel at the lower end. This fuel is generally 
 pulverized coal, blown in with an air blast. The material is 
 conveyed through the kiln by the rotation thereof and is agitated 
 thereby while subjected to the high temperature. The result 
 is to sinter the flue dust and to cause the small sintered particles 
 to agglomerate into nodules varying in size from an eighth of an 
 inch to an inch and a half in diameter and roughly spherical in 
 shape. These nodules are porous and of excellent quality, physic- 
 ally and otherwise, for use in a blast furnace" (Clark). The 
 West sintering process consists of a furnace with a movable 
 bottom on which a block of the material is built as fast as the con- 
 tinuous action of the heat will agglomerate or stick the particles 
 together. The material can be delivered to the furnace in several 
 ways: (i) Letting it fall from the roof and spreading it out me- 
 chanically to form a thin layer; (2) using a kind of injector 
 operated by air, and moving it over the area; (3) using a type 
 of continuous furnace with the bottom moving slowly along, the 
 dust being charged in definite places. After the block is built up 
 to the capacity of the furnace, it is withdrawn and the sinter 
 removed by a crane, and then broken to size as desired. If the 
 breaking is done while the mass is red hot there will be the mini- 
 mum of effort and cost (West). 
 
 Briquetted Borings. See Briquette. 
 
 Bristol Gas Pyrometer. See page 207. 
 
 British Formula. For quality: see page 340. 
 
 British Imperial Wire Gage. See page 188. 
 
 British Thermal Unit. See page 199. 
 
 British Yield Point. See page 471. 
 
 Brittle ; Brittleness. See also page 331. The tendency to rupture 
 under shock or stress, more particularly one which is suddenly 
 applied, without any appreciable elongation or reduction of area. 
 It is the opposite of toughness, but should not be confused 
 with hardness, as the latter is not synonymous. Mechanical 
 brittleness (Arnold) is where a piece of metal snaps off on any 
 
46 BRITTLE FRACTURE BUILT-UP TUYERE 
 
 attempt to bend it. Potential or vibratory brittleness (Arnold) 
 is where metal gives excellent tensile tests, will bend double 
 readily without fracture, but is nevertheless very liable to frac- 
 ture suddenly under vibration or alternation of stress, at a stress 
 below its elastic limit. Intermittent brittleness (Le Chatelier) is 
 where either brittleness or toughness may be produced according 
 to the previous treatment. Stead's brittleness is of rare occur- 
 rence, and is produced by heating very low carbon steel for a long 
 time (days) to between 500 and 750 C. (930 and 1380 F.). 
 The crystals become large, and the steel loses a large part of its 
 strength and ductility. Shortness is used synonymously with 
 brittleness: (a) red shortness or hot shortness, when hot; (b) 
 cold shortness, when cold; (c) blue shortness, brittleness when 
 cold, due to working at about a blue (temper color) heat, say 
 300 C. (5 70 F.) . Material slightly red short is also called tender 
 or weak. Slag shortness is brittleness due to slag inclusions. 
 
 Brittle Fracture. See page 178. 
 
 Brittle Hardness. See page 452. 
 
 Broad Twin. Seepage 125. 
 
 Broken Hardening. See page 228. 
 
 Broken Rails. See Rail Failures. 
 
 Brooman Process. See page 71. 
 
 Brown Coal. See Coal. 
 
 Brown Hematite: Iron Ore. See page 244. 
 
 Brown Mill. See page 41 7- 
 
 Brown Ore. See page 244. 
 
 Brown Process. See page 385. 
 
 Brown (George) Process. See page 114. 
 
 Brown (Henry) Process. See page 71. 
 
 Brown Pyrometer. See page 207. 
 
 Brown and Sharpe Gage. See page 188. 
 
 Browne Process. Pig iron is refined in any way, and alloys of iron 
 rich in manganese or silicon are then added. 
 
 Brownhill and Smith Mill. See page 417. 
 
 Browning; Browned Steel. See page 368. 
 
 Bubble. Blister: see page 71. 
 
 Bubbling Process (obs.). (i) Bessemer process; (2) puddling 
 process. 
 
 Bucher Process. See page 373. 
 
 Buckle. See page 58. 
 
 Buckled Plate. (i) A defect: see page 175; (2) plates which are 
 slightly dished to stiffen and strengthen them (Eng.). 
 
 Buckshot Cinder. See Slag. 
 
 Buckwheat Coal. See Coal. 
 
 Budd Process. See page 385. 
 
 Buddie. See Ore. 
 
 Buffing. See page 285. 
 
 Buffington Process. See page 368. 
 
 Bug. See Ladle. 
 
 Buggy. A flat car or wagon running on a narrow-gage track, 
 
 Buggy Casting See page 57- 
 
 Built-up Tuyere. Seepage 19. 
 
BULK MODULUS BY-PRODUCT COKE 47 
 
 Bulk Modulus. See page 335- 
 
 Bull Dog. See page 376. 
 
 Bull Head. See page 412. 
 
 Bull Ladle. See Ladle. 
 
 Bull Process. (i) Direct process: seepage 138; (2) purification 
 
 process: see page 385. 
 Bundle. See pages 94 and 507. 
 Bundle Iron (rare). Nail rods made by cutting up plates in a 
 
 slitting machine, and put up in bundles. 
 Bung. See page 1 14. 
 Bunsen Mill. See page 41 7- 
 Burden, Ore. Of a blast furnace: see page 34. 
 Burden Squeezer. See page 377. 
 Burgess Process. See page 166. 
 Burke Furnace. See page 154. 
 Burkheiser Process. See page 96. 
 Burning. (i) Of crucibles: see 112; (2) combustion: see page 202; 
 
 (3) of iron or steel: see page 226; (4) of molds: see page 298; 
 
 (5) of bricks: see page 395. 
 Burning in. (i) Casehardening: see page 67; (2) of enamels: 
 
 see page 370. 
 
 Burning off. In tempering: see page 231. 
 Burning on; Together. Form of soldering: see page 65. 
 Burning Zone. See page 226. 
 Burnishing. See page 285. 
 Burnt Lime. See pages 175 and 396. 
 Burnt Mine (Eng.). Roasted iron ore. 
 Burnt Ore. In malleablizing: see page 258. 
 Bursting Theory. Of rupture: see page 179. 
 Bushel (Busheling) Bar; Iron; Furnace; Scrap. See page 379. 
 Bushing Metal. See Brasses. 
 Bustle Pipe. See page 32. 
 Bustling (obs.). See page 74. 
 Butt. (i) The bottom end of an ingot, etc.; (2) the edge or 
 
 vertical surface of a plate or a piece of skelp; a term used in the 
 
 manufacture of welded pipe. 
 Butt Ingot. A short ingot, the last one poured from a heat, for 
 
 which there is not sufficient steel to fill the mold. 
 Butt Weld. See page 502. 
 Butt Welded Pipe ; Butt Welding. See page 489. 
 Buzzing (obs.). See page 74. 
 By-product. Not the chief product; secondary. 
 By-product Coke, Oven, Recovery. See page 96. 
 
C. (i) Chemical symbol for carbon; (2) symbol for the unit of 
 electric current, the ampere; (3) Centigrade scale: see page 204; 
 (4) indicating a falling temperature: see page 205. 
 
 Ca. Chemical symbol for calcium (lime), q.v. 
 
 Cb. Chemical symbol for columbium: see page 84. 
 
 Cd. Chemical symbol for cadmium: see page 84. 
 
 Ce. Chemical symbol for cerium: see page 84. 
 
 C/. Nature of carbon: see page 278. 
 
 Cl. Chemical symbol for chlorine: see page 84. 
 
 Co. Chemical symbol for cobalt, q.v, 
 
 Cr. Chemical symbol for chromium, q.v. 
 
 Cs. Chemical symbol for caesium: see page 84. 
 
 Cu. Chemical symbol for copper (Latin, cuprum), q.v. 
 
 C to C. Center to center, used as points of measurement in ma- 
 chinery, etc. 
 
 C. D. Cold drawn. 
 
 C. H. B. Charcoal hammered bloom. 
 
 C. H. No. . Charcoal hammered No. i. 
 
 C. H. No. F. Charcoal hammered No. i flange. 
 
 C. H. No. F. B. Charcoal hammered No. i fire box. 
 
 C. H. No. F. F. B. Charcoal hammered No. i flange fire box. 
 
 C. H. No. S. Charcoal hammered No. i shell. 
 
 C. I. Calorific intensity: see page 203. 
 
 C. J. Cold junction (of a couple) : see page 209. 
 
 C. No. i. Charcoal No. i. 
 
 C. No. i R. H. Charcoal No. i reheated. 
 
 C. P. (i) Chemically pure: see page 89; (2) calorific power: 
 see page 203. 
 
 C. R. Cold rolled. 
 
 Gabbling. See page 377. 
 
 Cadinho Furnace. See page 138. 
 
 Cadmia. See Zinc. 
 
 Caking Coal. See Coal. 
 
 Calcar. See page 181. 
 
 Calcareous. Limy. 
 
 Calcareous Ore. See page 243. 
 
 Calcination. Applying heat to a substance to drive off the volatile 
 matter, usually without the access of air; roasting is the same 
 operation with access of air, and usually at a higher temperature, 
 but below the fusion point. Calcination is frequently used as the 
 name for both. See also Ore. 
 
 Calcining Kiln. A kiln for calcining or roasting ores, limestone, 
 etc.; see page 181. 
 
 Calcite. See Flux. 
 
 Calcium. Ca; at. wt, 40; melt, pt., 760 C. (1400 F.); sp. gr., 1.85. 
 A silvery white metal moderately soft and malleable. Is not 
 found free in nature its principal occurrence being'as the carbon- 
 
 48 
 
CALCIUM CAP 49 
 
 ate, limestone. It alloys with silicon, and this material, termed 
 silico-calcium, has been tried as a deoxidizer for steel. The 
 element is sometimes referred to as lime, e.g., carbonate of lime, 
 instead of carbonate of calcium. 
 
 Calcium. Fluorspar: see Flux. 
 
 Calcium Chloride. (i) As a flux: see page 176; (2) in hot etching: 
 see page 287. 
 
 Calcium Fluoride. See Flux. 
 
 Calebasse (French). A crude form of furnace, used in place of a 
 cupola, for melting pig iron for small foundries. It consists of an 
 upper part (la tour) removable from a lower part (le creuset), 
 blast being supplied by a single tuyere. There is no tap hole, 
 the bottom part serving also as a ladle. 
 
 Calescence; Calescence Point. See page 265. 
 
 Caliber; Calibre. (i) The diameter, especially the inner diameter 
 or bore; (2) also used as a measure of length, especially of a gun, 
 in terms of the bore, thus an 8" gun 50 calibers long would have 
 a length of 400" or 33' 4". 
 
 Calibration. Of a testing machine: see page 469. 
 
 Calibre. Same as caliber, q.v. 
 
 Californian Furnace. See page 162. 
 
 Calipers. See page 187. 
 
 Callendar Dish Radio-balance. See page 207. 
 
 Callendar Gas Pyrometer. See page 207. 
 
 Callendar & Griffiths Electrical Resistance Pyrometer. See 
 page 208. 
 
 Callendar Recording Pyrometer. See page 210. 
 
 Caloric. See page 199. 
 
 Calorie. See page 199. 
 
 Calorific Agent. See page 200. 
 
 Calorific Intensity. See page 203. 
 
 Calorific Power. See page 203. 
 
 Calorimeter. Seepage 201. 
 
 Calorimetric Method. Of determining critical points: see page 
 265. 
 
 Calorimetric Pyrometer. See page 207. 
 
 Calorimetry. See page 201. 
 
 Calorizing. See page 372. 
 
 Calory (obs.). Calorie: see page 199. 
 
 Cam Squeezer. See page 377. 
 
 Camber. (i) In structural shapes and rails, the vertical curva- 
 ture measured by the versed sine; (2) in plates, the lateral 
 curvature, which in the case of structural material or rails is 
 called sweep. 
 
 Cambier Converter. See page 23. 
 
 Cammel's Process. See page 9. 
 
 Campbell's Formulae. For tensile strength: see page 338. 
 
 Campbell (H. H.) Process. See page 317. 
 
 Cancellated Structure. See page 126. 
 
 Cannel Coal. See Coal. 
 
 Cantilever Beam. See page 468. 
 
 Cap. To close the top of an ingot mold either with sand and an 
 4 
 
50 CAPILLARY STRUCTURE CARBON 
 
 iron plate, or else with a circular cast-iron or steel cap which fits 
 in a corresponding hole in the top of the mold; to stopper down 
 (Eng.). 
 
 Capillary Structure. See page 125. 
 
 Car Casting. See page 57. 
 
 Carbide Carbon. See page 273. 
 
 Carbide Steel. See page 443. 
 
 Carbo-allotropic Theory. Of hardening: seepage 280. 
 
 Carbon. (i) Influence on corrosion: see page 366; (2) as a re- 
 fractory: see page 398. 
 
 Carbon. C; at. wt., 12; sp. gr. diamond. 3.5; graphite, 2.5; 
 gas carbon, 2.35; charcoal, 1.57. Carbon occurs as three allo- 
 tropic varieties: the diamond, which is crystalline and color- 
 less or colored, occurring naturally, and rarely obtained in 
 an electric furnace; graphite, which occurs naturally in black 
 crystalline plates, or may be prepared artificially in an electric 
 furnace; and amorphous carbon, which is deposited on cool sur- 
 faces when carbonaceous matter is burned with an insuffi- 
 cient supply of air. An amorphous form of graphite has been 
 termed graphitite; a natural fuel, containing only traces of 
 oxygen and hydrogen, has been called schungite or graphitoid, 
 and it has been suggested that this name be used for fuels inter- 
 mediate between graphite and anthracite. The par bo n which 
 separates out in plates from cast iron during solidification is 
 called graphite or Irish. A substance having the appearance 
 of graphite is sometimes said to be graphitoidal. 
 
 Carbon is the principal constituent of all common fuels, 
 either solid, liquid, or gaseous, the most important of which 
 are coal and coke, used for heating and reduction. It is the 
 most important constituent of iron and steel, and is the chief 
 factor in making its varied properties and conditions possible. 
 In increasing amounts it raises the strength and the hardness, 
 and also the brittleness. The last is not a desirable quality, 
 but carbon causes less of this, combined with greater strength, 
 than any other element. This statement may require slight 
 modification in the case of some special steels. With increas- 
 ing carbon content, the elongation and the reduction of area 
 are decreased. With carbon, say, over 0.30%, iron can be 
 hardened by rapid cooling from above the critical point. 
 
 In making a chemical analysis of cast iron or steel, the carbon 
 is reported as combined carbon, graphitic carbon, and the two 
 together, total carbon. Combined carbon is that which is 
 combined directly with the metal or is dissolved in it, for which 
 Howe has suggested the name agraphitic carbon. Graphitic 
 carbon, graphite, or uncombined carbon is that which is simply 
 mechanically mixed with the metal. When combined carbon is 
 determined volumetrically, by comparing or matching the colora- 
 tion of a solution of the sample with that of a known standard, it 
 is termed color carbon, to indicate the method employed as 
 distinguished from burning the carbon in oxygen and weighing 
 the carbonic acid produced, called carbon by combustion or 
 combustion carbon. Howe uses the term missing carbon to 
 
CARBON ADDITIONS CARBONATE ORE 51 
 
 denominate that portion of the combined carbon in rapidly cooled 
 steel which is not shown by a color determination. The change 
 of carbon from one condition to another, i.e., from the combined 
 to the uncombined, or vice versa, is sometimes referred to as 
 transcarburization. 
 
 Carbon forms two very important oxides with oxygen, both 
 of which are gaseous under ordinary conditions. Carbon dioxide, 
 CO 2 , also called carbonic acid or carbonic anhydride, is the result 
 of the complete oxidation (combustion) of carbon. When acted 
 upon, at a high temperature, by additional carbon, it is partially 
 reduced, forming carbon monoxide, CO, also termed carbonic 
 oxide or rarely carbon oxide gas ; this reducing action, in connec- 
 tion with solid fuel, being rarely called carbon transfer. It is 
 valuable as a reducing agent but, in the case of iron, the action is 
 never perfectly complete. Carbon monoxide acts as a radical to 
 form compounds with certain elements, and is then termed 
 carbonyl. Iron apparently forms two such compounds, called 
 ferro-carbonyl or iron carbonyl, Fe(CO)s and Fe 2 (CO)7, when 
 finely divided iron, at comparatively low temperatures, is allowed 
 to remain in contact with the gas. 
 
 Carbon Additions. See Recarburization. 
 
 Carbon of Annealing. See page 272. 
 
 Carbon Bloom. See page 138. 
 
 Carbon Brick. See page 398. 
 
 Carbon of Cementation. See page 272. 
 
 Carbon Change. A change in the condition of carbon occurring 
 in iron or steel. 
 
 Carbon by Combustion. See Carbon. 
 
 Carbon Core. See page 299. 
 
 Carbon Deposition, Zone of. In blast furnace practice: see page 
 36. 
 
 Carbon Dioxide. See Carbon. 
 
 Carbon Free. A term used to designate metals and alloys practi- 
 cally free from carbon, which makes them more suitable for cer- 
 tain purposes. 
 
 Carbon Iron. Iron (either steel or cast iron) in which carbon is the 
 principal constituent. 
 
 Carbon Iron Company's Process. See page 138. 
 
 Carbon-iron Diagram. Iron-carbon diagram: see page 271. 
 
 Carbon Monoxide. See Carbon. 
 
 Carbon of Normal Carbide. See page 272. 
 
 Carbon Oxide Gas. See Carbon. 
 
 Carbon Steel. See page 443. 
 
 Carbon Theories. Of hardening: see page 279. 
 
 Carbon Tool Steel. See page 445. 
 
 Carbon Transfer. See Carbon. 
 
 Carbon Value. See page 87. 
 
 Carbonate. (i) The combination of a base with carbon dioxide; to 
 convert into a carbonate or to impregnate with carbon dioxide; 
 (2) (obs.) to carburize or carbonize: see Carburize; (3) see 
 Carbonization. 
 
 Carbonate Ore. See page 244. 
 
52 CARBONIC ACID CAST IRON 
 
 Carbonic Acid. See Carbon. 
 
 Carbonic Acid Theory. Of corrosion: see page 107. 
 
 Carbonic Anhydride. See Carbon. 
 
 Carbonic Oxide. See Carbon. 
 
 Carbonization. (i) Of fuels, coking or driving off the volatile 
 
 matter; (2) commonly used instead of carburization, meaning 
 
 impregnation with carbon: see pages 66 and 393. 
 Carbonized Iron. Usually a pig iron rendered brittle by excess of 
 
 silicon (Raymond). 
 Carbonizing Process. See page 66. 
 Carbonless. A term used to designate metals and alloys practically 
 
 free from carbon, which makes them more suitable for certain 
 
 purposes. 
 
 Carbonyl. See Carbon. 
 Carborundum. (i) As a silicon addition: see Recarburization; 
 
 (2) as a refractory: see page 398. 
 Carburet. (i) Carbide; (2) to carburize (rare). 
 
 Carburite. A,name given to a mixture of about 50% each of car- 
 bon and iron, used for recarburizing, particularly in the electric 
 furnace. 
 
 Carburize. Also termed carbonize; to introduce carbon (i) while 
 steel is molten by adding coke, coal, ferro-manganese, etc. (see 
 Recarburization), or (2) while in the solid state, by heating it in 
 contact with carbonaceous matter below its melting point 
 (see Cementation). 
 
 Carburizing-fusion Process. See page 113. 
 
 Carburizing Process. See page 66. 
 
 Carburizing Varnishes. See page 69. 
 
 Carinthian Process. See page 76. 
 
 Garment's Process. Consists in piling, reheating, and rolling 
 steel scrap with steel or iron turnings. 
 
 Camelry & Burton's Pyrometer. See page 210. 
 
 Caron's Cement. See page 68. 
 
 Caron's Method. Of hardening: see page 229. 
 
 Caron's Process. See page 68. 
 
 Carpenter & Reeling's Equilibrium Diagram. See page 272. 
 
 Carrier. See page 406. 
 
 Cascade Furnace. See page 146. 
 
 Case. (i) In cementation: see page 67; (2) of a mold: see 
 page 297. 
 
 Case Carbonizing. Case hardening: see page 67. 
 
 Case Hardening. See page 66. 
 
 Caspersson Process. See page 60. 
 
 Cast. (i) The act of tapping a blast furnace: see page 36; (2) 
 the metal taken from a blast furnace at regular intervals; 
 
 (3) a term for objects which are produced from the molten state. 
 Cast House. See page 27. 
 
 Cast Iron. (i) In general, usually called pig iron (q.v.), the 
 product obtained by reducing iron ore or similar materials 
 with carbon at a temperature sufficiently high to render it 
 fluid (molten). It is made in the blast furnace, sometimes 
 
CAST IRON ARMOR PLATE CASTING 53 
 
 in the electric furnace, and occasionally in the high bloomary 
 when that was in use. It contains a considerable proportion 
 of carbon (say, 2.20 up to about 7% usually from about 2.5 to 
 4%) and variable percentages of other substances, such as silicon, 
 manganese, phosphorus, sulphur, etc. It is hard and brittle, and 
 
 * cannot be rolled or forged at any temperature. (2) In a more 
 restricted sense the above product cast in its final form, the metal 
 for this purpose being usually first cast in pigs, and subsequently 
 remelted, although it is sometimes used in the molten state as it 
 comes from the blast furnace. Cast iron is defined by I.A.T.M. 
 as "Iron containing so much carbon that it is not usefully 
 malleable at any temperature." 
 
 Cast Iron Armor Plate. See page 9. 
 
 Cast Iron Mold. See page 296. 
 
 Cast Iron Pipe. See page 489. 
 
 Cast Seam. A fin formed in a casting when the mold has joints 
 into which some of the metal runs. 
 
 Cast Steel. (i) Crucible steel: see Crucible Process; (2) any 
 object made from steel in the molten condition. 
 
 Cast-welding Process. Pouring molten metal between objects to 
 be welded or fastened together. 
 
 Casting. (i) The operation of tapping a blast furnace; (2) melting 
 cast iron in a cupola for foundry work (obs.), sometimes called 
 running down ; (3) a metal object which receives its shape from a 
 mold (see Molding) into which the metal is poured while in a 
 molten condition and there allowed to solidify; (4) the operation 
 of filling molds, also termed teeming or pouring. A special kind 
 of casting known as ingots is the form in 1 which steel is cast 
 for subsequent rolling or forging; these are usually rectangular, 
 rarely round or hexagonal, in cross section; if more than twice 
 as wide as they are thick they are termed slab ingots ; the height 
 is usually two to four times the thickness or diameter. Castings 
 ordinarily as considered may be annealed or machined, or both, 
 but do not receive any rolling or forging. The manufacture of 
 castings is sometimes termed founding ; and the plant or shop 
 where they are made, a foundry. 
 
 Piping. During the solidification of any casting, the action 
 proceeds inward from the portion in contact with the walls of 
 the mold. (In this connection a core or interior division of a 
 mold is to be considered as a wall). As contraction proceeds, 
 since the metal itself is of smaller bulk when solid than when 
 molten, eventually a longitudinal cavity is left near the top, 
 where solidification last occurs, since below this point any in- 
 cipient cavity is immediately filled with molten metal. This 
 cavity is known as a pipe on account of its shape (also termed 
 cavity, contraction cavity, void, vug, sink hole, shrink hole, 
 draw hole). Liquid contraction is that which occurs up to the 
 point of solidification; used by Longmuir in connection with the 
 formation of cavities in the heavy parts of castings when an 
 outside skin had formed. Solid contraction occurs after solidifi- 
 cation is complete. Howe points out (Am. I. & S. List., 1915) that 
 during the early stages of solidification the exterior cools faster 
 
54 
 
 CASTING 
 
 than the interior (pre-neutral period), at some moment the rates 
 are the same (neutral moment), and afterwards the rates are 
 reversed (post-neutral period) ; that the relative rates of cooling 
 of the different portions govern the piping. The exterior or 
 major shrinkage is that which is measured by the external di- 
 mensions ; the interior or minor shrinkage is that which occurs in 
 an opposite direction in the interior of the casting tending to pro- 
 duce a pipe. The question is further complicated by the fact that 
 owing to variations in composition, due to segregation or initial het- 
 erogeneity, the solidification does not usually occur at a single 
 definite temperature but over a range (solidification range) 
 giving rise to progressive freezing. 
 
 FIG. 9. Pouring a heat of steel. 
 
 To facilitate the discussion of the phenomena of progressive 
 freezing, H. M. Howe adopted provisionally certain terms for 
 which he has given the following definitions : Frozen continent, 
 the part of the alloy which at any given instant under considera- 
 tion has already frozen; shore layers, those which have already 
 in part solidified, and yet in part remain unfrozen with pool-lets 
 or estuaries of still molten matter, or in other words the layers in 
 which freezing is actually going on; littoral region, that part of 
 the still unfrozen alloy immediately adjoining the shore layers, in 
 other words, the layers which have not yet actually begun freez- 
 ing but are about to; open sea, the still unfrozen mother metal 
 beyond the littoral region. Freezing, during which pools of 
 
CASTING 55 
 
 metal are isolated (which he terms the landlocking type), proceeds 
 by the outshooting of pine-tree crystals (so-called from the fan- 
 cied resemblance; also arborescent or dendritic), the tangled 
 branches of which lock up much of the impure metal of the littoral 
 region, and thus prevent it from diffusing centerward or, in short, 
 from segregating. But in the onion-skin type the successive 
 deposition of smooth concentric layers does not thus obstruct 
 the centripetal travel of the impurities. 
 
 Blowholes. Metals also evolve more or less gas during solidi- 
 fication, and any which cannot escape is mechanically held in 
 little pockets called blowholes (sometimes gas holes) which are 
 generally arranged symmetrically to the axis. * 
 
 Those occurring near the surface are called subcutaneous or 
 surface blowholes ; if open at the surface, cutaneous blowholes ; 
 those nearer the center, deep-seated blowhoies. A casting 
 
 FIG. 10. Ingot broken transversely showing subcutaneous 
 blowholes. 
 
 containing an excessive number of blowholes, rendering it un- 
 sound, is said to be honeycombed, porous, blown, blowy, 
 spongy, or mushy ; in such cases the blowholes are rarely termed 
 shrink holes. Since the space occupied by any blowholes corre- 
 sponds to an equal amount of contraction cavity, it is evident 
 that where there are many blowholes the pipe will not be so 
 extensive as where they are absent; in other words, other condi- 
 tions being similar, the space occupied by the blowholes and the 
 pipe is equal to that of the contraction cavity. Steel from which 
 the gases have been removed is sometimes referred to as degasi- 
 fied steel; it is correspondingly free from blowholes wnich 
 necessarily means a large pipe, hence called piping steel. Where 
 the steel contains much gas it has a tendency to rise in the molds 
 (rising steel) and the resulting casting contains rumerous blow- 
 holes, sometimes termed open steel. 
 
 Segregation is the concentration of the carbon and impurities 
 (in solution) into that portion of a metal casting which solidifies 
 last. Liquation is also used in the same sense, but Howe suggests 
 that segregation be used "to designate a concentration inward, 
 
56 CASTING 
 
 and liquation an expulsion of matter outward from the exterior 
 of the mass, but without insisting on the propriety of the termi- 
 nology. The metal other than the segregation is known as the 
 mother metal (also called segregans) : it is not closely analogous 
 to mother liquor, for it is in general the first crystallized and 
 purer substance, the segregation being the residue left from its 
 crystallization, while mother liquor is the impure residue left by the 
 early formed, relatively pure crystals." The term segregate 
 is also used for the segregated portion expelled in the freezing 
 of the earlier layers and usually found concentrated in the axis of 
 the ingot (axial segregate). Segregation was the term used by 
 Kosman (1903) to designate the separation of the constituents of 
 an alloy by partial melting (i.e., of one of them) ; in its usual sense, 
 
 PIG. ii. Ingot broken transversely showing deep-seated 
 blowholes. 
 
 as described above, it means a differentiation or purification 
 (of the mother metal). Howe introduced the terms segregation 
 excess for the excess of the percentage of an element in the 
 segregate over that in the segregans, and segregation deficit or 
 negative segregation for the opposite condition resulting from the 
 impoverishment of certain parts to provide the excess found in the 
 segregate. 
 
 With an ordinary casting the mold is made to provide for an 
 excess of metal above the casting proper. This extra metal 
 serves to keep the body of the mold full, and to receive any dirt or 
 scum (suilage) which rises (called head metai), and should also be 
 large enough to contain all the pipe. This portion of the casting 
 is called the sinkhead, sinking head, shrinking head, settling 
 head, feeder, feeding head, suilage piece, riser, rising head, head, 
 deadhead, or header ; the top of an ordinary ingot is rarely called 
 the sand. In the case of iron molds, if a lining of refractory 
 material is used around the sink head, to retard solidification at 
 that point, it is termed a hot-top sink head. The pressure 
 resulting from the height of metal, as in the sink head, is some- 
 times referred to as ferrostatic pressure, similar to hydrostatic 
 pressure for a head of water. If the rate of contraction is so un- 
 equal that the casting is distorted from casting strains, it is said 
 to be warped or sprung ; if the action is still more severe, so that sur- 
 face cracks result, it is termed checking or pulling, also the latter if 
 
CASTING 57 
 
 actual rupture results. Siag inclusions, also called cinder inclu- 
 sions, dirt inclusions, or simply inclusions, are particles of slag or 
 dirt occurring in the metal due to being mechanically held so they 
 could not escape to the top before solidification. Casting boil 
 usually refers to a condition in blast furnace practice where the 
 runners are damp and the hot metal generates steam causing ex- 
 plosions; in the same way with damp molds, particularly sand 
 molds, dampness leads to the formation of steam which causes a 
 more or less honeycombed or badly pitted surface on the casting. 
 Ingotism is the name applied by Howe to designate the very 
 coarsely granular condition of certain castings poured at a high 
 temperature and slowly cooled ; this structure tends to persist even 
 after annealing or other heat treatment and may require mechan- 
 ical working to destroy it. During the cooling, the cohesion be- 
 tween adjacent grains may not be sufficient to resist the con- 
 traction strains, so that there is a partial separation between them. 
 Any subsequent heat treatment therefore has no more effect in 
 uniting them than upon two pieces simply laid against each other; 
 mechanical working will usually effect a reunion provided, of 
 course, the surfaces are free from oxide or dirt. A scorched ingot 
 (Eng.) is one which has a needle structure and is brittle, perhaps 
 clue to being poured too hot. 
 
 Pouring or Teeming. The metal may be poured directly into 
 the top of the mold (top pouring, top casting), practically always 
 from some form of ladle (q.v.), but this method is generally 
 restricted to iron molds for ingots, as the falling metal is likely 
 to tear and destroy (wash) the surface of sand molds. In the 
 latter case the metal is introduced through a hole at the side or 
 bottom, by a separate channel called a runner which connects 
 with the mold itself by a gate, the metal in the runner is also 
 referred to by the same name, and the portion in the gate is called 
 the runner head. This method is known as bottom pouring 
 (casting) or ascensional casting, and the casting itself is similarly 
 designated, sometimes also as a rising casting. In filling ladles 
 from a furnace, or open top molds from a ladle, a split runner may 
 be used sometimes called a breeches runner, to permit of double 
 pouring. 
 
 Small molds are set on the foundry floor, but with larger sizes 
 it is generally necessary to place them in a pit (casting pit, 
 foundry pit, or open pit) so their tops will be readily accessible; 
 also to save the use of flasks. With ingots, the latter method 
 (pit casting) has been almost entirely abandoned, having been 
 superseded by setting the molds on small cars or buggies (car 
 casting, buggy or bogey casting) so they may be removed 
 expeditiously to the stripper (a machine for stripping the ingots, 
 i.e., lifting off the molds), and thence to the heating furnaces for 
 rolling or forging. The plate or base upon which an open bottom 
 mold stands is called the stooi. Open sand castings are those 
 made in molds simply excavated in sand without flasks. When 
 molten metal breaks through the mold the latter is called a 
 running mold. An ingot which is rolled or forged while the interior 
 is still liquid is termed a green ingot, and if it_cracks so some of the 
 
8 CASTING 
 
 interior escapes, a bled ingot. Chilled or (rarely) hardened cast- 
 ings are usually of cast iron which have been set in metal molds, 
 or where certain portions have been chilled by contact with metal 
 pieces set the walls of the mold. 
 
 A casting is said to be sharp when it conforms accurately 
 to the mold. Veins are irregular wavy markings on the surface 
 of castings which occur when too much blacking, etc., has been 
 used to coat the molds. Feathers are small fins or excrescences 
 of metal which have run between the joints of the mold. Scabs 
 are rough projections on a casting caused by the mold breaking or 
 being washed by the molten metal. Buckles or swells on castings 
 are caused by the mold being pushed out of shape by the molten 
 metal. In an iron casting a hot spot is a place where segregation 
 is high; such spots are sometimes porous or surrounded by porous 
 metal. To prepare a casting for use, it is necessary to clean it, 
 
 PIG. 12. Ingot split longitudinally showing pipe. 
 
 i.e., remove the gates, fins, scabs, and adhering sand. Smoothing 
 up the surface with grinding wheels, etc., particularly where the 
 runners and sinkhead have been broken off, is referred to as 
 dressing or fettling. The sand adheres much more tenaciously to 
 castings of steel than to those of cast iron; in the former case it 
 may be necessary to use a chisel and sledge or a pneumatic 
 chipper; in the latter case the castings, if small, are frequently 
 put in a machine resembling a barrel in which they are rotated, 
 usually with some sharp pointed pieces of metal, by means of 
 which the sand is removed and the surface polished; this machine 
 is called a rumble, rattle barrel, tumbler, tumbling barrel, 
 or shaking barrel. Where castings have to be fitted to each 
 other or to some object, the faces which are to come into contact 
 are frequently provided with thin metal strips cast on, which can 
 be cut until an accurate fit is obtained; these are called chipping 
 pieces or chipping strips, and their faces chipping faces. 
 
 Steel castings may be regularly annealed after removal from 
 the molds by reheating in a furnace to a cherry red for a certain 
 length of time (a) to remove any cooling strains, and (6) to give 
 a finer grain. Sometimes to avoid cooling-strains they are al- 
 lowed to cool slowly in the mold, and this is referred to as flask 
 annealing. In the case of cast-iron car wheels they are removed 
 from the chill molds as soon as possible and are frequently piled, 
 about six deep, in a circular pit provided with a cover, and there 
 allowed to cool slowly (pit annealing) . 
 
CASTING 59 
 
 Special methods of casting in some cases have for their object 
 a cheaper or more rapid operation, but in most cases are con- 
 cerned with the production of sound steel, i.e., free from piping 
 and blowholes or other interior defects, in which may be in- 
 cluded segregation. Below are given certain processes which are 
 usually based on one or more of the following principles : 
 
 1. Mechanical methods : 
 
 (a) Applying pressure in the mold before complete solidifi- 
 cation: fluid compression. 
 
 (b) Applying pressure to the ingot after removal from the 
 mold: Talbot's process. 
 
 (c) Replenishment (top replenishment) of molten metal at 
 the top. 
 
 (d) Slow pouring. 
 
 (e) Increasing blowholes to reduce pipe, and v ice versa. 
 
 2. Thermal methods : Retarding the cooling of the metal at 
 the top in relation to that below (Howe refers to retardation of 
 cooling at the top as top lag). 
 
 (a) Top heating: Applying molten slag, fuel, etc. 
 
 (b) Top insulation: A refractory lining at the top of the 
 mold (dozzle); sand, lime, etc., thrown on top of the 
 casting, or even contact with the air. An ingot is 
 dozzled (Eng.) when the mold has a refractory top. 
 
 (c) Increasing cooling effect at the bottom by inserting 
 metal pieces (for sand molds) or increasing the section 
 (for metal molds). 
 
 (d) The addition of a substance such as thermit to increase 
 the temperature at the top. 
 
 (e} Inverted molds (large end up). 
 
 (/) Charging ingots hot in the soaking pits. 
 
 3. Chemical methods : The addition of aluminum, silicon, etc., 
 to remove gases or cause them to remain in solution after solidifi- 
 cation. 
 
 Piping is increased by i (e} if blowholes are decreased; by 3. 
 Blowholes are increased by i (e) if piping is reduced. 
 
 Special methods of pouring. Pouring or teeming is the 
 operation of filling molds with molten metal, while the produc- 
 tion of castings in general is termed casting. With cast iron, 
 the ladle is practically always top pouring (see Ladle), the small 
 amount of slag floating on top of the metal being kept back with 
 bars. With steel, the bottom pouring style of ladle is almost 
 universally employed on account of the large amount of slag 
 which must be prevented from entering the molds, and also the 
 necessity for avoiding splashing the sides of the molds. Ordi- 
 narily the same ladle into which the steel is run from the furnace 
 or converter is used for pouring. To insure better mixing (par- 
 ticularly of small charges) the steel is sometimes poured' from one 
 ladle into another (repouring process), and if this is done through 
 the bottom of the first ladle, instead of over the top, it will elimi- 
 nate almost entirely the slag, and so permit additions to be made 
 
60 CASTING 
 
 in the second ladle without any danger of rephosphorization. 
 In Caspersson's method of pouring, the steel is run into a vessel 
 with a number of perforations in the bottom (colander funnel) 
 which divide it up into a number of fine streams with the object of 
 giving the contained gases a better opportunity to escape. 
 Sauveur's overflow method of pouring was devised for the preven- 
 tion of pipes in ingots, by having each mold overflow into the 
 next, and thus have a quantity of molten steel constantly on top 
 of each ingot until the ingot had almost completely solidified. 
 Owing to early chilling of the stream, it was found applicable 
 only to small ingots, and there were also difficulties in handling 
 from having to break the ingots apart. In the Beardmore and 
 Cherrie process a shallow mold with a large surface is employed 
 instead of the ordinary deep type, with the idea of promoting 
 the escape of gases, and so reducing the number of blowholes. 
 Van Riet claimed to avoid the formation of blowholes by placing 
 on top of the mold a box with a small hole in the bottom arranged 
 to prevent the slag from running in; it would not appear to be of 
 much value unless a top-pouring ladle were used. To shorten 
 the fall of the steel, and so prevent the entraining of air, Billing 
 employed a mold with a piston forming the bottom and so ar- 
 ranged that, starting at the top of the mold, it could be lowered as 
 the mold was filled. In Hainsworth's method the steel from a 
 converter is poured into a deep stopperless runner which dis- 
 charges into the molds, preferably through an intermediate 
 stopperless funnel with several nozzles, one over each mold. To 
 prevent splashing the sides of the mold, Posnikoff suspends in 
 the mold a thin sheet-iron tube through which the steel is 
 poured; this melts as the steel rises over it. 
 
 Regulating the Rate of Cooling. The Ansaldo process is on the 
 same principle as an electric induction furnace. The metal in the 
 mold is heated by a secondary current induced by the primary 
 current in a coil of wire surrounding the mold. This coil can be 
 moved vertically so that when the mold has been filled it occupies 
 a position at the top of the mold to keep the metal molten there as 
 desired. The De Laval feeding head (De Laval ring) consists 
 of a conical or funnel-shaped crown lined with refractory material 
 heated to at least a red heat. This is placed on top of the mold 
 during pouring, and afterward helps to keep the steel liquid at that 
 point so it will fill any pipe which tends to form. The Gathmann 
 process consists in casting ingots in inverted molds, the bottom 
 portion having much thicker walls, the object sought by both 
 these means being to decrease the rate of cooling at the top and 
 increase it at the bottom of the ingot. In the Hadfield process 
 the ingots are cast with the large end up. On top of the mold is 
 placed a cast iron box lined with refractory material, the mold 
 being filled with steel to within a few inches of the top of this box. 
 A small amount of fusible crushed slag is thrown on, and, when 
 this is melted, charcoal is also added. A weak blast, in a series 
 of jets, impinges on the charcoal to promote its combustion, the 
 temperature secured being sufficient to keep the steel in the hot 
 top fluid and so fill up any pipe forming beneath. In J. Munton's 
 
CASTING 6 1 
 
 method attainment of the same object is sought by pouring, 
 molten slag on top of the ingot before the steel has solidified. 
 J. B. Nau attempts the same thing in a somewhat different 
 manner: the ingpt mold constitutes the bottom or hearth of a 
 heating furnace, and is arranged so it can be lowered; the bottom 
 of the mold is cooled by a series of water pipes so the cooling of the 
 ingot will proceed from the bottom upward. Riemer's method 
 is to use a gas flame for heating the top of the ingot. Thermit 
 (see Goldschmidt Process), also called anti-piping thermit, has 
 been employed to reduce piping, a can of the thermit attached to 
 an iron rod being thrust into the steel near the top, after the mold 
 has been filled, so that the heat generated by the reaction will 
 keep it molten. A later development is to thrust the can down as 
 near the bottom of the mold as possible so the reaction will stir 
 up the metal and thus give the gases a better chance to escape; 
 fresh metal from a ladle may also be added to keep the mold full. 
 Group casting is where a number of molds on one bottom plate 
 are bottom poured simultaneously by means of a central runner 
 (git) or mold (git mold) into which the steel is run. This is 
 sometimes referred to as the hen and chickens method. In the 
 Pink method, the molds are supported on a turntable. A modi- 
 fication of group casting, usually termed multiple casting, is 
 where a number of molds are superposed and fed through a 
 common runner. In Scott's method (intended for tire ingots) 
 the molds are built up with cast-iron rings and fire-brick slabs 
 with a small central hole interposed to make several cheeses 
 (round slabs for forging into railroad tires) which are readily 
 broken apart after solidifying. The pouring is done from the 
 bottom. Turner combines several molds in one larger mold, and 
 also piles several on top of each other, separated by division 
 bricks provided with small holes. They are fed at the bottom of 
 the lowest mold by a runner. J. B. D'A. Boulton's method con- 
 sists in employing ingot molds without bottoms which are 
 superposed; they are filled successively, and the shrinkage 
 in each is compensated by fluid metal from the ingot above; 
 an asbestos washer with a small aperture is placed between the 
 ingots so the bottom one can be easily removed. The operation 
 is intended to be continuous, the ingots being sheared off at the 
 bottom (the molds are split longitudinally so as to be easily 
 removed), and fresh molds set in position on top of those 
 already filled; the lowering of the molds is performed by 
 hydraulic mechanism. A. Kurzwernhart and C. Bertrand have 
 suggested a method with several modifications : the ingot mold 
 consists of two portions, a lower, divided into several smaller 
 molds, and an upper undivided one. The sides of the two main 
 portions are kept separate by means of a slab of fire-brick 
 inserted between them. By this means the portions may be 
 easily separated after the casting of the ingots. The upper 
 portion of the mold is comparatively shallow, and is lined 
 with refractory material, termed the gas collector, and it is 
 claimed its use permits of very small and sound ingots being 
 produced. In R. Smith-Casson's method a split mold is em- 
 
62 CASTING 
 
 ployed with divisions nearly coming together so the ingots are 
 connected at the two opposite edges by small webs of metal, and 
 can later be separated by a blow of a sledge or else sheared 
 off; they are bottom cast. J. Parkes causes metal to rise upward 
 through a series of slab molds of different and gradually diminish- 
 ing sizes with the idea of producing pieces of steel of nearly the 
 size desired for plates, etc., free from blowholes by the pressure 
 Of the long column. 
 
 Mechanical treatment for producing solid castings. See 
 also Fluid Compression. Vacuum casting consists in creating 
 a partial vacuum in the mold after pouring the steel, to remove 
 the dissolved or occluded gases, and so prevent the formation 
 of blowholes. Forsyth rapidly hammers the mold after pour- 
 ing, the jarring of the steel interfering with coarse crystalliza- 
 tion. F. Kapfl gives slight vertical jerks to the mold and its 
 contents during the progress of solidification. Chernoff agitates 
 the metal during solidification by rotating the mold at varying 
 speeds with occasional reversals. R. W. Hinsdale has devised 
 two methods. In the first he uses a single stationary, bottomless, 
 water or steam-cooled mold. The ingot is drawn down by mech- 
 anism as soon as its crust has solidified, till only its upper end 
 remains in the mold, when a second is cast upon it, uniting with it 
 in the center, and feeding its pipe, yet readily detached later. 
 There must be little or no taper to the mold, so there is danger of 
 the ingot cracking and bleeding. In the second method the mold 
 is mounted on trunnions; after pouring, the top of the ingot is 
 chilled, and the mold turned upside down with the purpose of 
 having the pipe entirely enclosed by steel, so the interior of the 
 pipe will not be oxidized, and will weld up on subsequent working. 
 A method which may be mentioned here consists in stirring up 
 the steel in the ladle with a machine known as Allen's agitator. 
 This has two arms fastened to a revolving shaft which ^can be 
 raised or lowered. It was primarily intended for mixing the 
 additions with- the steel, but was also found to effect a con- 
 siderable evolution of gas and so reduce the number of blow- 
 holes in the ingots. An operation termed poling is sometimes 
 employed for nearly the same purpose: a pole of green wood 
 is thrust into the steel in a ladle, and the gases distilled off serve 
 to stir up the contents, and also exert a certain amount of re- 
 ducing action on any oxides present. This method has also 
 been tried with cast iron for foundry work with the idea that a 
 certain amount of purification will result. Centrifugal casting 
 consists in rotating or revolving the molds after pouring, and while 
 the steel is still molten. The pressure exerted, which is much less 
 than with fluid compression, tends to remove the occluded gases 
 and produce sound castings. L. Sebenius pivoted the ingot 
 molds on swinging arms which were rotated at a rate of about 
 125 revolutions per minute, so that the molds were caused to take 
 a horizontal position. In Stridsberg's modification the mold was 
 rotated about its longitudinal axis instead of having it as the 
 radius. P. Huth's method was devised especially for producing 
 wheels, etc., with a hard rim or face and a soft interior. The 
 
CASTING 63 
 
 mold was caused to rotate about its center as an axis, and hard 
 steel was poured in first and thrown to the circumference of the 
 mold; soft steel was then run in to complete the center. Of 
 course any other combination could be made. 
 Fluid Compression. Also called liquid compression or plastic 
 compression, has for its object the treatment of ingots to make 
 them perfectly solid throughout by the elimination of blowholes 
 and pipe. It consists in applying pressure in some form to the 
 steel while it is solidifying. In the earlier methods gaseous 
 pressure was applied between the top of the ingot and the top 
 of the mold (closed after pouring). Bessemer's process con- 
 sisted in the combustion of gas-yielding substances, and in the 
 vaporization of certain liquids. In W. A. Jones' process steam 
 under considerable pressure was introduced. In Krupp's process 
 liquid carbonic acid gas was used. The La Chaleassiere process, 
 like Jones', consisted in casting under a steam pressure of 88 to 
 147 pounds to the square inch. -In the Galy-Cazalet process a 
 mixture of charcoal and saltpeter (similar to gunpowder with the 
 sulphur left out) was used. 
 
 In the Whitworth process the steel is cast in a cylindrical 
 mold with- vertical walls, and a hydraulic plunger is forced 
 down on top of the ingot. Hinsdale's process is somewhat 
 similar to Whitworth's: a plunger with a hollow end is brought 
 down on top of the ingot and breaks through the upper crust; 
 the liquid steel which enters this hollow is stated to be the 
 only scrap; it was employed for small, high-carbon ingots. 
 In G. W. Billing's process a common mold was used, its bottom 
 being replaced by a piston which was forced upward as soon 
 as pouring was completed, the top of the ingot being pressed 
 against a resistance plate which had meanwhile been slipped 
 in (Howe). In Daelen's process the steel was cast in a power- 
 fully clamped iron mold. If top cast, a plunger was driven 
 through a hole in the top of the mold, its cross-section, being 
 only a small part of that of the ingot. If bottom cast, a plunger 
 was driven in horizontally into the runner which was larger at 
 that point, the top of the mold being closed (Howe). In the 
 Neuberg process the steel is cast in tapered molds, reinforced 
 by steel hoops which are shrunk on. The inside is hexagonal 
 in section except for about 6" at the top which is circular to 
 admit the plunger of a hydraulic press which exerts a pressure 
 of 400 to 700 tons for about half a minute to a minute. In S. T. 
 Williams' process the ingot is cast in an ordinary tapered mold, 
 one side of which is removable; when the walls of the ingot are 
 sufficiently thick, a convex liner is slipped inside the removable 
 side of the mold and forced against the ingot. Lilienberg's 
 process is somewhat similar: Ingots are cast in the ordinary 
 manner, which, after removing the molds, are pressed between 
 two wails, one of which is movable and the other stationary. 
 Illingwortn's method was to employ a split mold with a metallic 
 filler which was removed when the ingot had partially set and 
 pressure was applied. H. D. Hibbard's method was similar to 
 Illingworth's except a refractory filler was employed and the ingot 
 
64 CASTING 
 
 was cast with the large end up. In Harmet's process (also 
 called St. Etienne process, compression by wire drawing, or 
 draft fluid compression) a tapered ingot is driven upward in a 
 . tapered mold by means of a hydraulic plunger, the wedge action 
 exerting enormous pressure on the sides. Talbot's process 
 consists essentially in removing the ingot from the soaking pit 
 before the central portion has solidified, reducing it partially in a 
 blooming mill with the object of closing up any cavities, and then 
 restoring it to the soaking pit until it is in the usual condition 
 for rolling, after which the rolling is finished in the regular way. 
 The term liquid squeezed has been applied to steel treated in this 
 manner. 
 
 Compound or composite castings (ingots) are those made by 
 combining together different grades of steel, sometimes with 
 wrought iron, so that certain parts of the casting will be hard, 
 while others will be soft and tough. This method is intended 
 principally for ingots to be rolled or forged into various articles 
 such as armor plate, etc. Where the center is soft while the 
 outside- is hard, the term soft centered (mild centered) steel 
 is applied; in the reverse case, hard centered steel. In the 
 Wild process ingots were to be formed of wrought iron and 
 steel by taking a piece of iron of the desired shape, heating it 
 to a welding heat, placing it in the mold, and pouring steel 
 around it; there was trouble from oxidation of the iron, and 
 also the iron was found to roll out faster than the steel. Von 
 Nawrocki divided the mold into two or more parts by thin 
 sheets of wrought iron, when steel and iron (soft steel?) were 
 run into the separate compartments. Congreaves patent 
 composite steel, or compo, intended for axles, boiler plate, etc., 
 was produced by placing in the mold a cage of wrought-iron 
 bars separated by perforated plates, around which steel was 
 poured. Sibut's process is very similar to the above. In the 
 process devised by Marel Brothers (for armor plate) a ribbed 
 plate of wrought iron was first made. This was heated to a white 
 heat, sprinkled with borax, and in this condition put in a mold, 
 and molten steel run around it or merely against one face; 
 the ingot was subsequently worked down. Wm. Siemens 
 poured hard steel upon softer, or divided up the ingot mold in 
 some way. B. Lauth proposed a^very similar method. In 
 the process devised by Evans and Spencer for producing suitable 
 material for axles and shafts, a central core of wrought iron was 
 placed in the mold, and around this a harder grade of steel was 
 run, and the ingot subsequently worked down. Elbridge 
 Wheeler used two grades of steel from two converters; metal 
 of one grade was poured into a mold provided with a core which 
 was then removed and the other grade run into the cavity. 
 Charles Saunderson's process consisted in making blooms of 
 wrought iron containing grooves over which iron strips were 
 welded, and the holes thus formed were filled with steel. In a 
 modification, he surrounded a bloom with a tube, and filled the 
 space with steel. In either case the product was heated and 
 worked down. 
 
CASTING BOIL CASTING SHOE 65 
 
 Miscellaneous methods. The Szekely method" consists in 
 employing metal molds, one of the chief points being to coat the 
 molds with chalk and paraffin. Shaw also employs metal molds. 
 Slavianoff's electric casting method appears to be simply a 
 method of melting steel by connecting it to one terminal of a 
 strong electric circuit, the crucible in which it is to be melted, or 
 the plate on which it is to be cast being attached to the other. 
 In the so-called sand core process, a sand core is cast in the ingot 
 which is afterward worked down as usual; it was claimed that 
 the sand did not injure the material, but this, as well as any 
 advantage is extremely doubtful. In Norton's fluid rolling 
 process, fluid steel was to be worked direct into sheets by pouring 
 it through revolving rolls properly adjusted, with the idea of 
 preventing blowholes, and reducing the usual amount of scale. 
 Bessemer's method for making continuous sheets consisted m 
 running molten steel between two water-cooled steel rolls, 
 separated a suitable distance; the speed of the rolls was regulated 
 according to the thickness of the sheet. In Whiteley's process 
 for the production of plates, molten steel was run into a revolving 
 cylinder and formed a shell which was taken out, cut open by 
 a saw, and then rolled down. Pielsticker and Mueller's process 
 was devised for producing bars, rods, and similar material direct 
 from fluid steel by first passing it through dies, and then finishing 
 the resultant material in a rolling mill or under a hammer. 
 Mellen rod casting process employs a special machine tor t 
 continuous production of rods; molten metal is poured into the 
 molds arranged in an endless chain. 
 
 Malleable or cast-iron castings are sometimes united ^by 
 heating in contact to a high temperature; this is termed burning 
 together. It is sometimes necessary to make an addition to a 
 casting to complete or to replace a portion which has been broken 
 off. For this purpose the casting already made is placed in a 
 mold of the proper shape and molten metal poured in. The solid 
 metal must be heated up to a sufficiently high temperature, and 
 there are two methods which are usually distinguished as (a) 
 casting on, where the solid metal is heated with a flame, and (b) 
 burning on, where the molten metal is first caused to run into 
 and out of the mold until the solid portion has been sufficiently 
 heated, when the outlet hole is closed, and the mold allowed to 
 fill up. Wm. Chalk's method for uniting a sleeve or boss of cast 
 iron, etc., on a wrought-iron shaft consists in heating the shaft 
 to a welding temperature, putting it in a suitable mold, and pour- 
 ing around it the molten metal. Falk's method is somewhat 
 similar, and is intended for uniting the ends of rails; an iron mold 
 is placed around the ends, and extremely hot metal is then 
 poured around them until they are partially fused and will unite 
 readily. 
 
 Casting Boil. See page 57- 
 Casting Box. See page 297. 
 Casting On. Form of soldering: see above. 
 Casting Pit See page 57- 
 Casting Shoe. The fore-hearth for an open hearth furnace. 
 
66 CASTING STRAINS CEMENTATION 
 
 Casting Strains. See page 56. 
 
 Catalan Forge; Process. See page 138. 
 
 Catalysis; Catalyst; Catalytic Agent. See page 87. 
 
 Catalysis Theory. Of passivity: see page 364. 
 
 Catch the Carbon on the Way Down. See page 315. 
 
 Catcher. See page 430. 
 
 Catcher's Side. See page 41$. 
 
 Cathode. See page 89. 
 
 Cation. See page 89. 
 
 Cat's Eyes. See page 1 14. 
 
 Caustic Potash ; Soda. The commercial hydrate or hydroxide of 
 potassium and sodium respectively. 
 
 Cave. Crucible furnace: see page 114. 
 
 Cavity. Pipe or gas pocket: see page 53. 
 
 Celite. See page 396. 
 
 Cell. See page 121. 
 
 Cell Wall. See pages 121 and- 126. 
 
 Cellular Deformation. See page 126. 
 
 Cellular Theory. Of steel: That when solid it consists of a net- 
 work of grains or crystals. 
 
 Celsius Scale. Of temperature degrees: see page 204. 
 
 Cement. (i) In cementation: see pages 67 and 70; (2) binding 
 the grains of metals: see page 281. . 
 
 Cement Bars. See page 71. 
 
 Cement Carbon. See page 272. 
 
 Cement Steel. See page 71. 
 
 Cement Theory. See page 281. 
 
 Cementation. (i) In the metallurgy of iron and steel the carburi- 
 zation, or impregnation with carbon, at a temperature below the 
 melting point of the metal. The iron must be in intimate contact 
 with the carbonaceous matter, and air must be excluded. While 
 the general principles are the same, there are three modifications 
 which are readily classified in accordance with the depth and the 
 nature of the carburization : (a) bars carburized throughout 
 or nearly so to a varying degree referred to specifically as the 
 cementation process used in the crucible process and also in the 
 manufacture of cutting tools; (6) armor plate (q.v.), deeply 
 impregnated but on one side only; (c) where the depth of pene- 
 tration is very slight, usually called case hardening, for objects 
 or parts of objects which must be superficially hard to resist 
 wear. (2) Metallic cementation (see also Protection, page 370), 
 a term used to denote impregnation with a metal or alloy in 
 much the same manner as with carbon, resulting in a metallic 
 coating for the purpose of resisting corrosion. Siliciuration 
 indicates impregnation with silicon, as when platinum is heated 
 in contact with silicious material and hydrogen. (3) Rarely 
 used in the sense of treating solid cast iron with oxides to effect 
 its decarburization (see Malleable Castings, page 257). (4) 
 Rarely the reduction, without fusion, of iron ore by means of 
 carbonaceous material (see Direct Processes, page 134). 
 
 For the general process of cementation the terms carbonization, 
 carbonizing process, and carburizing process are also used. 
 
CEMENTATION 67 
 
 Cementation which is wholly or almost complete is sometimes 
 called total cementation to distinguish it from case hardening 
 which is also known as partial cementation, surface cementation, 
 superficial cementation, case carbonizing, rarely burning in, 
 and sometimes (especially in the case of gears and pinions) 
 armored or armorized. The term supercarburized has been 
 applied to armor made by the Harvey process. Where the cemen- 
 tation is partial, the (outer) portion affected, the cemented 
 zone, is called the case, and the inner unaffected portion the 
 core, heart or nucleus. These two last terms are more usually 
 restricted to blister bars not completely cemented, otherwise they 
 would be distinguished as core cemented. 
 
 The carbonaceous material used is the cement. Depending 
 upon its state it may be solid, liquid, gaseous, or, if a com- 
 bination of two or all, mixed. It may be further classed, ac- 
 cording to its rate of action, into mild, slow or gradual; 
 quick or rapid; and violent or sudden. In general the velocity 
 of cementation depends upon the rate of penetration of the car- 
 bon. This in turn is differently affected by different elements 
 which may be present in the metal. On the basis of certain 
 experiments Guillet considers it proved that the substances 
 which retard cementation are those which are found in solution 
 in the iron (nickel, titanium, silicon, and aluminum) ; and that the 
 substances which accelerate cementation are those which seem 
 to exist in the state of double carbides, replacing a part of the 
 iron of the cementite (manganese, chromiam, tungsten, and 
 molybdenum Giolitti). In determining the rate of penetration 
 of carbon, cementation curves may be employed, which are 
 plotted with one of the coordinates as the depth (measured in 
 mm. or in.) and the other as time (hours). 
 
 The temperatures ordinarily employed are 850 to 1100 C. 
 (1560 to 2010 F.) and the rate of cementation increases with 
 increase of temperature. However, with carbon monoxide and 
 carbonaceous matter the amount of carbon deposited will be 
 greater at a lower temperature, say around or below 700 C. 
 (1290 F.). In this latter case the bulk of the carbon may be 
 deposited in the free state, that is, without combining with or 
 dissolving in the iron, by the same reaction as occurs in the blast 
 furnace, thus: 
 
 2 CO = CO 2 -f- C (deposited in the iron); 
 CO 2 + C = CO (further reaction with the cement). 
 
 The equilibrium of the system CO : CO2 : C according to these 
 reactions, that is, the carbon concentration, is proportional to the 
 concentration of carbon dioxide, and varies inversely as the 
 temperature. According to Boudouard while it is only 0.7% 
 at 1100 C. (2010 F.) it increases to 42% at 700 C. (1290 F. 
 Giolitti). These reactions also take place in regular cementation. 
 If, owing to the loss of CO 2 the efficacy of the cement is impaired 
 (exhaustion) it may be restored by a short exposure to the air or 
 by the introduction of a limited supply of oxygen while still hot 
 (regeneration). 
 
68 . CEMENTATION 
 
 In certain cases four different zones may be observed under the 
 microscope: (a) the central portion of untouched metal (hypo- 
 eutectoid steel), (6) where the carbon gradually increases to the 
 eutectoid content (also hypo-eutectoid), (c) eutectoid steel, and 
 (d) a hyper-eutectoid region; there might also be included (e) 
 the case where, owing to subsequent oxidizing influences, the 
 outer portion has been more t>r less decarburized. It is desirable 
 to avoid any sharp changes in structure as these prevent the 
 proper continuity and gradation of the physical properties. 
 Where the outer layer is high in carbon, say i to 1.5%, it 
 usually presents a coarsely crystalline appearance (pig face) 
 which is objectionable owing to its lack of coordination with the 
 interior, causing it to flake off (exfoliation or splitting). The 
 separation or segregation of cementite so that it exists in the free 
 state is sometimes called liquation. According to Giolitti, the 
 elimination of a first series of discontinuities those due to liqua- 
 tion of cementite can be obtained by avoiding the formation of 
 a hyper-eutectoid layer containing free cementite. This can be 
 done by the use of carbon monoxide acting as an equalizer with 
 other cements. Further, to avoid or reduce in the cemented and 
 hardened zones, sudden variations in the concentration of carbon, 
 to which are due the phenomenon of exfoliation: (i) avoid effect- 
 ing the cementation at too low a temperature, and in every case 
 cement above Ar 3 ; (2) avoid slow cooling after cementation and 
 before quenching (to prevent separation of cementite and ferrite 
 and so cause greater discontinuity). Cyanides are not necessary 
 under the conditions for ordinary cementation, as the trans- 
 portation of carbon to the metal is effected, at least for the 
 most part, by carbon monoxide (Giolitti). 
 
 Of the solid cements wood charcoal has been, and still is, 
 the most widely used particularly for total cementation. For this 
 purpose the temperature is usually kept at about the melting 
 point of copper, say 1085 C. (1985 F.), and old and new char- 
 coal is employed; if the charcoal is all new, a lower temperature 
 is necessary to prevent local o/ercarburization, and the time ex- 
 tended correspondingly to get the required depth. Hard wood 
 charcoal is more effective than soft but more costly. Caron's 
 process, still used, was to mix about 40 parts of barium carbonate 
 with 60 parts of wood charcoal (Caron's cement or hardenite). 
 This produces a very active cement due to the contained COz; 
 when its action becomes reduced it is easily restored or regener- 
 ated by exposing to the air while still hot. Bone dust or bone 
 ash is a solid cement which evolves a certain amount of hydro- 
 carbons; after repeated use it is termed spent bone. Charred 
 leather, horns or hoofs, etc., are all used, principally in mixtures. 
 Coke saturated with a heavy oil is sometimes employed. For 
 the purpose of increasing the effect by the action of cyanides, 
 Eaton's process consisted in mixing ferrocyanide of potash with 
 wood charcoal. In Bates' process the mixture consisted of 
 carbon, cryolite, spent lime, rosin, and soda, with the later 
 addition of oxide of nickel which he claimed was reduced and 
 formed an alloy with the iron. There are various mixtures, 
 
CEMENTATION 69 
 
 some sold under trade names, which are usually more rather than 
 less complicated and not always better than some of the standard 
 substances. 
 
 Carburizing varnishes are mixtures which can be painted on 
 special parts, and in addition to being capable of imparting 
 carbon must also be adherent without cracking or melting off. 
 
 The use of liquid or fusible cements for cementation by 
 immersion has been practised for some time, usually where only 
 a very thin case is desired, hence sometimes called skin harden- 
 ing. Leaving aside the use of cast iron which has been proposed 
 several times but at present is not applied, the only liquid cements 
 consist of pure salts or saline mixtures (hence chemical harden- 
 ing) ; most commonly simple or complex salts of prussic (hydro- 
 cyanic) acid, either alkali or alkaline earth cyanides, ferro- 
 cyanides and ferricyanides. The substance most frequently 
 and almost exclusively used as a liquid cement for cementation 
 by immersion is potassium cyanide (potash hardening). In 
 general the pieces are immersed in the already fused bath, kept 
 between 850 and 900 C. (1560 and 1650 F.), and left in 3 
 to 15 minutes, according to the depth of cementation desired. 
 If the piece is of medium size, say about i to 6 pounds., and not too 
 irregular in form, the rule can be followed to immerse cold, and 
 remove when the temperature has exceeded 850 to 880 C. 
 (1560 to 1615 F.). Zones of uniform thickness are obtained 
 from 0.03 to o.io mm. (0.0012" to 0.004"), according to the 
 temperature and the time. The content of carbon near the 
 surface reaches 0.9% C or higher, sufficient to render it, after 
 quenching, inattackable by a file. It is not advisable, by this 
 process, to try to obtain deeper than 0.15 to 0.20 mm. (0.006" to 
 0.008") by prolonging the operation or using a higher tempera- 
 ture, since then zones are obtained in which excessive percentages 
 of carbon and sudden variations give rise, after quenching, to 
 intense brittleness and exfoliation (GioKtti). 
 
 Salts derived from the radical CN exercise a specific carburizing 
 action which has not yet been studied with precision. At 700 
 C. (i29oF.) nitrogenous cements furnish a thin cemented zone 
 with less than 0.55% carbon but very rich in nitrogen, the per- 
 centage of which may exceed 0.5%. In these cemented zones 
 J. Kirner observed a special constituent which he designated 
 by the name flavite, the proportion of which increased with in- 
 crease in the precentage of nitrogen. 
 
 A patented method termed infusion method of hardening was 
 similar to the above, claims being made that owing to the special 
 ingredients used the action proceeded to a greater depth and that 
 the change from the treated to the untreated parts was very 
 gradual. 
 
 Partially fusible cements consist of a mixture of an infusible 
 base with a fusible constituent and have been proposed for use 
 in a similar manner. 
 
 The gaseous cements may consist of various hydrocarbons 
 or carbon monoxide, the advantage being the uniformity secured 
 particularly where the pieces treated are of complicated shape. 
 
70 CEMENTATION CARBON CEMENTATION PROCESS 
 
 Carbon monoxide as the base in mixed cements acts as an equali- 
 zer in securing uniformity and avoiding sharp changes in content. 
 The gas employed may be diluted by an inert gas when it is 
 desired to restrain its action. Carbon monoxide, for example, is 
 said to be isolated when it is caused to act alone. 
 
 Electrical processes for cementing (termed by Sang electro- 
 cementizing), as in the manufacture of steel, consist principally 
 in the use of the current for heating purposes. There are also 
 methods proposed (and patented) from time to time by which it 
 is claimed the current is employed directly for securing better 
 results, the current acting as a carrying agent. 
 
 An anti-cement is a coating which prevents or impedes cemen- 
 tation and is employed for the protection of a certain part which 
 is not to be cemented; for example, in the DeDion-Bouton 
 process copper is deposited from a solution of copper sulphate. 
 The theory of cementation is based on the observed fact that 
 certain elements (in this particular case, carbon) have the power 
 of diffusing through iron. Arnold and McWilliam have divided 
 the elements most commonly found in steel into those which are 
 migratory and those which are fixed. Leplay's hypothesis was 
 that carbon monoxide was formed by a reaction of carbonaceous 
 matter with air and that this alone acted as the carrier of, 
 and deposited, carbon. Laurent's hypothesis was that the 
 cementing action was due to a vapor of carbon and not to solid 
 carbon. It has been proved, however, that solid carbon, as such, 
 has the power of diffusing into iron; the usual action is due to 
 both gases and to solid carbon. 
 
 Cementation Carbon. See page 272. 
 
 Cementation Curve. See page 67. 
 
 Cementation Furnace. See below. 
 
 Cementation by Immersion. See page 69. 
 
 Cementation Process. Also called converting process. This 
 process, in its special sense, consists in impregnating bars of 
 wrought iron or soft steel with carbon, at a temperature below its 
 melting point, and is used (chiefly in England) for the production 
 of high carbon bars to be employed in the manufacture of crucible 
 steel or shear steel. The bars are usually of pure Swedish iron 
 made by the Walloon process (see page 79), *%" to 3" wide, %" 
 to %'' thick, and about 12 feet long, 8 to 13 tons constituting a 
 charge (Harbord and Hall). They are packed in layers, sepa- 
 rated by charcoal (sometimes called cement) in fire-brick cham- 
 bers (converting pots) heated externally by flues, and ^ forming 
 part of the cementing furnace. The top of the pot is closed 
 with an arch of wheel swarf, which later frits and forms an. air- 
 tight cover. The furnace attains its full temperature in about 
 3 to 4 days, at which it is maintained about 7 to 8 days for mild 
 heats, about 9^2 days for medium heats, and about n days for 
 high carbon heats; the cooling down requires about 4 to 6 days. 
 To test the progress of the operation, trial bars (test- bars, tap 
 bars, spies, or regulator test pieces) are drawn at intervals 
 through a special, small aperture, provided for the purpose, and 
 examined. If wrought iron has been employed, the finished bars 
 
CEMENTATION PROCESS 7 1 
 
 will be found covered with blisters (also rarely called beads and 
 bubbles) formed by the reaction between the contained slag^and 
 the carbon, from which comes the name blister bar or blister 
 steel; at one 'time this was sometimes termed German steel. 
 This phenomenon is absent when steel bars are treated; both 
 products are known as- converted bars, cement (cemented) bars or 
 cement steel, at one time also called artificial steel because not 
 made direct from the ore. 
 
 Bars desired of very high carbon may be retreated, and are 
 known as doubly converted bars or glazed bars. Since the 
 carbon penetrates from the outside inward, the percentage will 
 decrease progressively to the center. In very mild bars there is 
 an unaltered core of mild steel called sap, and very hard bars are 
 easily distinguished by being what is known as flaked, as on 
 fracture they present bright cleavage planes. Two examples of 
 this are. (a) bar W thick, outside, 0.98%, center, 0.10%, 
 average, 0.45%; (6) bar W thick, outside, 1.50%, center, 
 1.15%, average, 1.33%. In Sheffield the six grades of cement 
 steel have the following names: 
 
 i. Spring heat carbon about 0.50% 
 
 2. Country heat. 
 
 3. Single -shear heat. . . 
 
 4. Double-shear heat. . 
 
 5. Steel-through heat. . 
 
 6. Melting heat 
 
 0.63% 
 
 0.75% 
 1.00% 
 1.25% 
 1.50% 
 
 The sap or soft center of No. i has a dull appearance (killed) 
 and does not stare or look raw, i.e., have a bright fracture. It is 
 important to have the transition from one grade to the other as 
 gradual as possible: when the line of demarkation is too abrupt, 
 the process has been carried out too rapidly, and the bars are said 
 to be flushed. If, owing to a leak in the pot, air has entered, the 
 outside of the bars will be somewhat oxidized, and are called 
 aired bars. If the temperature has been a little too high, so the 
 outside has fused slightly, they are called glazed bars. Blister 
 bars rolled or hammered down at a yellow heat are known as 
 plated bars or bar steel. The following are various methods 
 suggested or tried from time to time: 
 
 In Bink's process compounds of cyanogen were specified, and 
 currents of nitrogen, carbonic oxide, and ammonia, or ammonia 
 alone, were to be passed through decarburized molten iron. 
 
 In Bpullet's process iron was to be cemented with a substance 
 consisting of sugar, horn dust or shavings, animal fat or blood, 
 and wood charcoal dried and pulverized. 
 
 In Brooman's process iron was to be melted in pots with 
 compounds of cyanogen; such compounds might consist of 
 charcoal, salt, brick dust or oxide of manganese, sal ammoniac, 
 and ferrocyanide of potash. 
 
 Henry Brown's process consisted in cementing iron in a 
 granulated condition in close pots with carbon: iron which was 
 being puddled was taken out of the furnace as soon as it became 
 granulated, and before it was pasty; it was then broken up until 
 
Ground 
 
 Redbrick 
 
 Firebrick 
 
 Stone 
 
 Rubble 
 
 Concrete 
 
 Ground 
 
 PIG. 13. Transverse section of cementation converting furnace 
 A, converting pots; B, firegrate; C, flues for distributing heat; 
 D, short^'chimneys communicating with stack; E, conical hood 
 or stack; F, manhole for introducing or withdrawing charge; G, 
 holes for removal of trial bars; H, charging holes. (Harbord and 
 Hall, "Metallurgy of Steel".) 
 
CEMENTED ARMOR PLATE CHAMOTTE 73 
 
 it would pass through a 2o-mesh screen, after which it was put in 
 long pots with wood and cemented as usual. 
 
 James Boydell's process was to cement the product obtained 
 by puddling wrought iron melted in a cupola. 
 
 In Holland's process silk waste of every kind was to be terrified, 
 i.e., dried at a high temperature without being carbonized, and 
 then ground to a fine powder, and used for cementing. 
 
 Kimball's process consisted in cementing bars with a special 
 mixture prepared from sal ammoniac, borax, alum, salt, vinegar, 
 urine, soot, burnt leather, and horsehoofs. 
 
 Kraff and Sauve's process consists in employing charcoal, 
 etc., previously heated to about 50 C. (122 F.) and dipped 
 in some liquid hydrocarbon. 
 
 Charles Macintosh heated wrought iron to a white heat in 
 closed pots, and then introduced carbureted hydrogen or carbo- 
 naceous gases through suitable openings. 
 
 A. V. Newton's process consisted in melting pig iron in a 
 special furnace, and blowing on it jets of hydrocarbon gases 
 and atmospheric air. 
 
 Moses Poole specified the use of prussiates and ferrocyanides. 
 G. C. Thomas claimed the decided novelty of a cementing 
 (?) mixture consisting of salt, ferrocyanide of potash, bichro- 
 mate of potash, and animal charcoal. 
 
 In Arthur Wall's process iron was to be cemented by em- 
 bedding bars, in an ordinary cementing furnace, in a mixture 
 of charcoal and chalk and zinc filings ; electric currents were 
 to be passed through the bars for a certain period. 
 
 J. J. W. Watson claimed the use of electricity for carburizing 
 iron; he also employed sulphate of manganese with carbona- 
 ceous matter and lime, either with or without the application of 
 an electric current. 
 
 Cemented Armor Plate. See page 8. 
 
 Cemented Bars; Steel. See page 71. 
 
 Cemented Zone. See page 67. 
 
 Cementing Furnace. See page 70. 
 
 Cementing Fusion Process. See page 113. 
 
 Cementite. See page 272. 
 
 Cementite Carbide. See page 273. 
 
 Cementite Point. See page 273. 
 
 Cementitic Steels. See page 445. 
 
 Cementito-Austenitic Steel. See page 276. 
 
 Centigrade Scale. Of temperature degrees: see page 204. 
 
 Centrifugal Casting. See page 62. 
 
 Centrifugal Extrusion. See page 121. 
 
 Chafery (obs.). A sort of blacksmith's forge. 
 
 Chalcopyrite. See page 245. 
 
 Chalk Method. See page 65. 
 
 Chalut and Clouet Process. See page 113. 
 
 Chalybeate. Containing iron, usually applied to water. 
 
 Chalybite. See page 244. 
 
 Chambered Core. See page 299. 
 
 Chamotte. Powder of old clay crucibles: see page 396. 
 
74 CHAMPIN PROCESS CHARCOAL HEARTH 
 
 Champin Pneumatic Process. See page 21. 
 
 Champlain Forge. See page 137. 
 
 Channeling. See page 35. 
 
 Chapelet Furnace. See page 154. 
 
 Chaplet; Chaplet Block; Nail. See page 299. 
 
 Chappuis Gas Pyrometer. See page 207. 
 
 Char. (i) To carbonize; (2) coke or charcoal (Eng.). 
 
 Charcoal. The carbonaceous residue resulting from the dry 
 distillation of wood, amounting to about 26%. Owing to 
 its ease of preparation and its comparative freedom from sulphur 
 and ash, it has long been used in certain metallurgical processes. 
 Ledebur gives the approximate composition of good air-dried 
 charcoal as: 
 
 Volatile matter 4% 
 
 Fixed carbon 84 
 
 Ash 2 
 
 Sulphur under 0.05 
 
 Phosphorus 0.05 
 
 Moisture . 10 
 
 Red Charcoal is the name given to the product obtained by 
 charring wood at a low temperature and which is of inter- 
 mediate composition between wood and charcoal. 
 
 The wood was formerly charred exclusively in piles (some- 
 times called meilers) covered over with earth or turf, small 
 openings being provided for the entrance of the air and for 
 the escape of the gases. The most usual method is to employ 
 a charcoal kiln, which is a stall consisting of two side walls 
 and a back wail, the front and top being covered with earth 
 and turf as in the case of the pile. It is now frequently pre- 
 pared in charcoal ovens or charcoal retorts, similar in prin- 
 ciple to those used in the manufacture of coke; in the former 
 case, combustion of the gases tukes place inside the chamber, 
 while in the latter, the chamber is externally heated by flues 
 or a fire. 
 
 Charcoal Bars. (i) Wrought iron rods or flats; (2) wrought iron 
 bars made by some charcoal hearth process, or from charcoal pig, 
 to be rolled into sheets: see page 75. 
 
 Charcoal Blacking. See page 298. 
 
 Charcoal Finery. See page 383. 
 
 Charcoal Furnace. See pages 39 and 181. 
 
 Charcoal Hearth; Charcoal Hearth Cast Iron. See page 383. 
 
 Charcoal Hearth Processes. Rarely called forge process ; bustling 
 and buzzing are very obsolete terms (Percy). These processes 
 are designed for the production of wrought iron (charcoal iron)," 
 usually by refining cast iron, occasionally by melting scrap before 
 a tuyere with charcoal for fuel, the product being obtained in a 
 pasty condition, and containing a certain amount of slag, but 
 less than puddled iron. Only the latter method is at present 
 employed in this country. 
 
 In general the furnaces or hearths are (Howe) like the Catalan 
 and bloomary hearths (see Direct Processes), for reducing iron 
 
CHARCOAL HEARTH PROCESSES 75 
 
 from the ore, low, rectangular chambers, sometimes roofed, and 
 with one or more tuyeres. The chief difference is that in refining 
 cast iron much more strongly oxidizing conditions are brought 
 about, chiefly (i) by melting the metal down in drops before 
 the tuyere, repeatedly, if need be, so that it passes in a state of 
 minute subdivision and with great surface exposure through a 
 part of the hearth where the atmospheric oxygen is in excess; and 
 (2) by the action of the basic ferruginous slag with which the 
 metal is mixed during the earlier stages, and with which it is 
 covered during the later stages, to ward off the strongly carburiz- 
 ing tendency of the charcoal. Only a good quality of pig iron 
 (nearly always charcoal pig) is used, as the process is expensive, 
 and is employed only for a high grade of wrought iron. The pig 
 iron is often given a preliminary refining to eliminate most of the 
 silicon. 
 
 The. hearths are usually built of unlined cast-iron plates, at 
 least in part water -cooied. Brick-work is avoided as the silica 
 would enter the slag. 
 
 The processes may be classified (Howe) according to the 
 number of times the metal is melted down before the tuyere, 
 (i) into single melting, double melting, and triple melting (or 
 German or breaking up) ; (2) into Walloon and non-Walloon. 
 
 The hearth may be covered or uncovered; if the latter it is 
 called an open fire or open hearth; if the former, a closed hearth 
 The bloom, after rolling, is called finer's bar (corresponding to 
 muck bar in puddling), and after piling and rerolling, finished 
 charcoal bar. German steel is an obsolete name for the product 
 obtained by melting white or refined pig in a charcoal hearth; it 
 may also be made of poorer quality in a very hot puddling 
 furnace 
 
 Product. "From given cast iron the charcoal hearth process 
 yields better wrought iron then puddling, perhaps in part be- 
 cause the charcoal lacks the sulphur which the mineral fuel 
 of the puddling furnace contains, and of which a little may 
 enter the metal, but chiefly for the following reason. In both 
 processes we can decarburize the pasty metal throughout its 
 mass only by stirring it vigorously, exposing fresh surfaces to the 
 action of the atmosphere and of the strongly decarbunzing basic 
 slag, and this stirring intentionally mixes slag with metal to 
 effect decarburizing. We thus get a ball of stiff pasty wrought 
 iron mixed with much slag. In some of the charcoal hearth 
 processes we get rid of most of this slag by remelting this ball; 
 holding it aloft we allow its metal to fall drop by drop, and collect 
 it in a new ball, which we carefully avoid touching, and which is 
 thus relatively free from slag. In the puddling process we cannot 
 do this, and must content ourselves with squeezing out as much 
 of the slag as we can in hammering or rolling. Charcoal iron, 
 then, is in a manner intermediate between common wrought iron 
 and ingot iron (fluid-cast steel, see Classification) in that it is 
 remelted and cast while molten into a malleable mass; but in- 
 stead of being cast into a slagless mold as in true ingot-metal- 
 making processes, it is poured upon a bath of slag of which a very 
 
76 CHARCOAL HEARTH PROCESSES 
 
 little inevitably becomes mixed with the metal. Charcoal iron 
 is raised but slightly above its melting point and for a few minutes 
 only; is cast drop by drop through an atmosphere rich in car- 
 bonic oxide and carbonic acid into a white-hot bath of slag, 
 falling in all but a few inches; ingot iron is held for a very con- 
 siderable length of time far above its melting point, is cast in a 
 thick stream, through a cold atmosphere of oxygen and nitrogen, 
 usually into a cold cast-iron mold, often falling several feet. In 
 the charcoal hearth, drop of metal follows drop in such a way that 
 neither pipe nor blowhole nor microscopic cavity seems to form; 
 ingot metal is so cast that pipes or blowholes or microscopic 
 cavities or all three arise. Charcoal hearth iron is purposely 
 kept as free as possible from slag, ingot metal is purposely kept 
 practically absolutely free from slag" (Howe). 
 
 In the Bohemian process, mottled or even gray pig is used, 
 and the blooms are reheated in the same hearth. Charcoal is 
 first charged, and on top of this some slag and the pig which 
 is melted down slowly, the iron cake which is formed being 
 frequently raised up. The cinder is tapped at intervals. Finally 
 the bloom is welded to the end of a rod and taken to the hammer; 
 any particles of iron that remain in the hearth are retreated. 
 
 Corinthian process: The pig used is white, and is cast in 
 thin disks about 3 to 6 feet in diameter and Y' thick, which are 
 given a preliminary heating or roasting for about 30 hours, 
 which removes some of the carbon as well as the silicon. The 
 disks are broken up and piled on charcoal in the hearth, which 
 is of about the usual type. The metal is gradually melted 
 down, care being taken that no pieces of unmelted metal drop 
 into the melted portion. The bloom is divided into two pieces, 
 and each of these into six, which are reheated in the same hearth. 
 A charge takes about 2^4 hours. 
 
 The Corinthian raw steel process is very similar to the pre- 
 ceding, except that the removal of the carbon is not carried 
 so far. Mottled, rarely gray, pig, or the round disks described 
 above, are used. The bottom is made of charcoal and binding 
 material rammed hard in layers. The pig is melted down 
 with addition of cinder. The cinder is then taken off, the 
 iron piled up in the middle of the hearth and melted down 
 again, when it reposes on the bottom under a layer of slag. 
 The slag is again removed, and the bloom taken out, hammered, 
 etc. The product is apt to be very heterogenous ; about three- 
 quarters of it is good steel. The process takes about 2^ hours. 
 The blooms are cut in two, and reheated separately in the same % 
 hearth. 
 
 Fosberg's Swedish hearth is very similar to the ordinary 
 Lancashire hearth, except it has three tuyeres (one at the back) 
 instead of two, and also an adjustable bottom whose height 
 can be regulated as desired. 
 
 Franche-Comte process: The hearth is nearly rectangular, 
 and" is composed of cast-iron plates; it is closed, and the bottom 
 may be cooled between heats with water underneath. It is 
 provided with one or two tuyeres, and the blast is preheated 
 
CHARCOAL HEARTH PROCESSES 7 7 
 
 by the products of combustion. Pigs of gray cast iron are 
 melted down as in the Swedish Wallon process, i.e., are grad- 
 ually pushed forward as their ends melt otf. This continues for 
 about 90 minutes or less, during which the bloom from the 
 preceding charge, having been cut in two, is reheated in the 
 same hearth, and forged, three heatings and forgings being 
 needed for each half bloom. The pasty mass, which has mean- 
 while accumulated on the hearth bottom, is now lifted above 
 the tuyeres and gradually melted down, falling drop by drop 
 past the tuyeres. This occupies some 20 to 25 minutes more. 
 Those parts of the mass resulting from this second fusion which 
 are still imperfectly decarburized must be raised up and melted 
 down a third time (Howe). 
 
 The J. J. Hudson process, recently employed in this country, 
 consists in melting the charge between layers of charcoal in a 
 specially designed furnace of the open hearth type. The furnace 
 is preheated by means of oil or gas, and a thick bed of charcoal is 
 provided upon which the charge of pig is made. By the intro- 
 duction of blasts of cold air through tuyeres, the metal is melted 
 and boiled, filtering through the charcoal which consumes the 
 impurities, eliminating them from the mollen mass. Charcoal 
 may be added at any time during the heat and is generally added 
 near the end to dispel any injurious gases that may arise, thereby 
 insuring complete purification of the metal. The method has the 
 effect of purifying and refining the iron by decarburization and 
 oxidation. It is stated that it may be applied to the manufacture 
 of charcoal steel (higher in carbon) with equally valuable results. 
 (Iron Age, 4/18/12). 
 
 In the Lancashire process, American Lancashire process, and 
 Swedish Lancashire process, all of which are about the same, 
 the hearth consists of unlined, water-cooled, cast-iron plates, and 
 is provided with two (sometimes only one) tuyeres. The blast 
 is somewhat preheated by the products of combustion. If not 
 enough slag remains from the last operation to cover the bottom, 
 some is added, and charcoal is piled up to above the tuyeres. On 
 top of this is placed the pig in lumps (sometimes previously 
 heated in the same hearth), which is covered with charcoal and 
 the blast turned on. The pig melts in drops which, in passing the 
 tuyere area, become partially decarburized and collect on the 
 bottom. When it is all melted, it is worked with bars so it will 
 become mixed with the slag and be thoroughly purified. When 
 this has taken place, as shown by the fact that it is stiff and pasty 
 the mass is raised above the tuyeres and melted down again to 
 free it from the intermingled slag, care being taken that this 
 remelted lump is not cut by the working bars, as this would intro- 
 duce fresh slag. The lump is then taken from the furnace and 
 hammered, etc. The operation takes about iM to i% hours. 
 About 275 to 300 pounds of pig are used for a charge. A modi- 
 fication of this process consists in simply melting soft scrap, 
 which is practically the last stage in the method where pig is 
 employed. This is used to some extent in this country for mak- 
 ing charcoal sheets, etc. 
 
78 CHARCOAL HEARTH PROCESSES 
 
 Pi'i 
 Tl 
 
 The Lombardy process has the peculiarity of subjecting the 
 
 >ig to a special refining before the process proper commences. 
 
 The pig is charged in the hearth on top of charcoal, and melted 
 slowly in about 2}^ hours, with only a small amount of blast. 
 
 During this period charcoal is thrown on occasionally,, and 
 each time this is done the pig is raised up. The charcoal is 
 then taken out, the slag chilled with water and removed, and 
 hammer slag mixed with the molten metal, which becomes pasty 
 and is taken out and broken up into six pieces. The hearth is 
 then cleaned and filled with powdered charcoal which is 
 thoroughly stamped down. Each of the pieces of metal is then 
 melted down separately with slag or charcoal, and subsequently 
 refined as usual. The time required for the entire charge is not 
 less than 18 hours, and the charcoal required amounts to about 
 2^ times the weight of the pig (Percy). 
 
 The Paai steel process is very similar to the Carinthian. The 
 pig is melted down to form a cake, while pieces of the previous 
 bloom are reheated in the cinder and hammered. The bottom 
 cake is then exposed, and, if already hard and steely, is finished, 
 but if otherwise, it must be further treated. For this purpose 
 the charcoal is renioved from the hearth, and rich scale or oxides 
 are stirred into the iron until it begins to get hard, when the 
 charcoal is put back and the metal melted down; after this the 
 bloom is hammered, etc. Some of the metal remains in the 
 hearth, and forms part of the next charge (Percy). 
 
 The Rohnitz process resembles the Bohemian most nearly. 
 Reheating and refining operations take place simultaneously 
 in the same hearth. Mottled or even gray pig is used, and 
 the metal after melting down is treated as in the Lombardy 
 process (Percy). 
 
 In the Salzburg process gray pig is used, which is subjected to 
 some preliminary treatment as in the Lombardy process. Re- 
 heating and refining are conducted in the same hearth, but the 
 former is finished before the latter begins. A considerable amount 
 of cinder is formed, and it must be tapped out frequently. 
 
 In the Siegen process the bottom of the hearth is formed of 
 a mixture of crushed cinder and hammer slag. Mottled or 
 white pig, in long pieces, is treated exactly as in the Walloon 
 process. J > 
 
 In the Siegen raw steei finery process the hearth is much 
 as usual, with the bottom composed of pieces of fine-grained 
 sandstone; there is usually one tuyere. The blooms are cut 
 in pieces and reheated in the same hearth, one piece being 
 melted down with the next charge. The pig is melted down 
 in successive portions, on top of the charcoal, and rich cinder 
 is thrown in to oxidize the carbon; if this action has gone too far, 
 spiegel is added. The excess of cinder is tapped off, and when 
 the ball is of the proper size and consistency, it is removed, 
 hammered, cut up, and graded by fracture, the product being 
 heterogeneous. One charge requires about 7 to 8 hours. 
 
 In the slag bottom process, practised in Styria, the hearth 
 is similar in construction to the Franche-Comte", etc. The 
 
CHARCOAL HEARTH PROCESSES 79 
 
 bed is composed of rich finery cinder, broken up small and 
 stamped down carefully. White pig iron is used in small pieces, 
 which are melted down on charcoal. The bloom is divided into 
 eight pieces, which are reheated in the slag in the same hearth. 
 A charge takes about i^ to 2 hours (Percy). 
 
 In the South Wales (South Welsh) process, pig iron is first 
 melted down in a coke refinery, and there part of its silicon and 
 carbon are removed by the action of the blast. It is then tapped 
 out into a pair of charcoal hearths, the relatively acid slag being 
 held back, and any which runs into the charcoal hearths being 
 carefully removed. The partly solidified metal is broken up and 
 piled near the tuyere. After melting down, it is repeatedly 
 raised slightly from the bottom, apparently as in the Lancashire 
 process. The slag is tapped off from time to time. As soon as 
 the metal has come to nature, it is withdrawn and hammered 
 (Howe). When the metal melts down, after being piled up in 
 front of the tuyere, the operation of working it is termed sink- 
 ing a lump or sinking. The last cinder solidifies into a more or 
 less cylindrical piece, hollow in the center, due to chilling around 
 the point of a bar inserted through the cinder hole, and is called a 
 fox tail. The ball is hammered into oval slabs which are nicked 
 in seven or eight places, quenched in water, and broken into 
 pieces called stamps, which are graded according to their frac- 
 tures. These are reheated in a furnace called a hollow fire 
 which has two chambers, in one of which coke is burned, and in 
 the other the iron is heated so it does not come in contact with 
 the fuel, but only with the gas. The stamps are laid on a peel 
 (staff), the blade of which is of the same quality of iron. After 
 heating, they are welded together, then nicked and bent over so 
 the staff material forms the top and bottom. 
 
 The Knobbling process is practically identical with the South 
 Wales. 
 
 Stridsberg's hearth is provided with four tuyeres and two 
 working doors on opposite sides, and is practically a double 
 Lancashire hearth. 
 
 The Styrian charcoal process (Styrian open hearth) employs 
 the ordinary type of hearth. The bed is formed of small pieces 
 of charcoal, mixed with a small amount of cinder from the pre- 
 vious heat. Reheating and refining are performed simultane- 
 ously in the same hearth. White pig iron, in small pieces, is 
 slowly melted down on charcoal in two portions; this is arranged 
 so that the second portion shall begin to melt about 10 minutes 
 after the commencement of the first. A small amount of hammer 
 slag is thrown on the melted metal which has previously been 
 denuded of charcoal. The bloom is cut into four pieces for 
 subsequent hammering, etc. A heat lasts about 2 hours (Percy). 
 
 The Styrian raw steel process, according to Tunner, bears 
 such a close resemblance to the preceding that it is difficult 
 to^distinguish between them, and frequently soft iron is made by 
 this process. 
 
 The Tyrol process closely resembles the Styrian. 
 
 The Walloon process, or Swedish Walloon process, is used 
 
8o CHARCOAL IRON CHEMICAL FORMULA 
 
 in Sweden for making bars to be converted into blister steel. 
 The hearth is rectangular, and is built of unlined, water-cooled, 
 cast-iron plates, and is provided with one tuyere. One or two 
 very long pigs of white or mottled cast iron are melted down 
 drop by drop, being pushed forward as their ends melt off, 
 till enough to yield a bloom of from, say, 84 to 93 pounds has been 
 melted. This may take some 20 minutes, during which the 
 pasty metal, gradually reaching the bottom of the hearth, is 
 worked constantly. The pasty mass is now broken up, raised 
 above the tuyere, and melted a second time, apparently much as 
 in the Lancashire method. During this time the bloom from the 
 preceding charge is heated in this same hearth, held steeply in- 
 clined (Howe). 
 
 The Eifel Walloon process and the Styrian Walloon process 
 appear to have no essential differences from the above. 
 
 Charcoal Iron. (i) Pig iron smeited with charcoal: see page 343; 
 (2) wrought iron made by some charcoal hearth process (q.v.), or 
 from charcoal pig: see page 379. 
 
 Charcoal Kiln. See Charcoal. 
 
 Charcoal Pig.- See page 343. 
 
 Charcoal Plate. See page 433- 
 
 Charcoal Refinery. See page 383. 
 
 Charcoal Retort. See Charcoal. 
 
 Charcoal Sheet. See page 433. 
 
 Charcoal Steel. See page 77- 
 
 Charcoal Wrought Iron. Wrought iron produced by some char- 
 coal hearth process, or from charcoal pig. 
 
 Charge. (i) In a blast furnace, the amount of material composing 
 a round; (2) in other furnaces, the total amount of material for a 
 heat. 
 
 Charger. In the crucible process: see page 114. 
 
 Charging Box. See page 314. 
 
 Charging Door. Of a furnace: see pages 182 and 183. 
 
 Charging Machine. See page 314. 
 
 Charging Tray. Charging box: see page 314. 
 
 Charkt. (obs.).' An old English name for a kind of charcoal. 
 
 Charles's Law. See Gas. 
 
 Charpy Pendulum Hammer; Test. See page 482. 
 
 Check Analysis. See page 82. 
 
 Checkers; Checkerwork. See pages 203 and 311. 
 
 Checking. Cracking : see pages 56 and 1 10. 
 
 Cheek. See page 297. 
 
 Cheese. See page 61. 
 
 Chemical Action; Affinity. See page 84. 
 
 Chemical Analysis. See pages 82 and 284. 
 
 Chemical Bond. See page 86. 
 
 Chemical Compound. See page 83. 
 
 Chemical Energy. See page 84. 
 
 Chemical Equation. See page 87. 
 
 Chemical Equivalent. See page 87. 
 
 Chemical Formula. (i) Meaning: see page 86; (2) for physical 
 properties: see page 337. 
 
 ' " 
 
CHEMICAL HARDENING CHEMISTRY 8 1 
 
 Chemical Hardening. See page 69. 
 
 Chemical Hardness. See page 331. 
 
 Chemical Impurity. See impurity. 
 
 Chemical Metallurgy/ See Physical Metallurgy. 
 
 Chemical Methods of Etching. See pages 286 and 287. 
 
 Chemical Passivity. See page 364. 
 
 Chemical Purity. See page 89. 
 
 Chemical Reaction, Reagent. See page 86. 
 
 Chemical Solution. See pages 88 and 107. 
 
 Chemical Symbol. See page 86. 
 
 Chemically Dissolved/ See page 107. 
 
 Chemistry. Matter is anything which occupies space. It is 
 considered made up of very small particles called molecules or 
 atomic aggregates, which again are composed of atoms. A 
 molecule is the smallest particle of matter which can exist in the 
 free state, and an atom is a smaller particle which enters into 
 chemical combination. This constitutes the so-called atomic 
 theory upon which chemistry is based. Physics is concerned 
 principally with the relations of molecules, and chemistry with 
 the relations of atoms. Quite recently the electron theory or 
 electronic theory has been advanced that the atom is not, as 
 formerly assumed, the smallest possible unit, but is itself a system 
 consisting of a nucleus charged with positive electricity and elec- 
 trons, each of which carries the minimum unit charge of negative 
 electricity. Meta -element was the name suggested by Crookes 
 for a supposed variety of an element whose existence was indi- 
 cated by spectrum analysis. 
 
 There are three states of matter : the solid, the liquid and the 
 gaseous. The solid state is due to the strong attraction or 
 cohesion between the particles; with liquids the attraction is 
 much less, while with gases there is a repulsion. Different, 
 more specific, terms have been adopted to indicate changes 
 affecting the state or condition of matter. Transformation 
 signifies a change of the same substance from one form to another 
 without change of state, as in the case of allotropy; a special 
 case of transformation is sometimes known as transmutation, 
 a term employed by the alchemists to signify the change of one 
 metal into another, as lead into gold; conversion is still used in 
 this latter sense, as in the conversion of pig iron into steel. 
 Transition is a change of state as solid to gaseous. Transference 
 is the change of place of substances or forces, as the point at which 
 a force is applied. Translation is the bodily removal of a sub- 
 stance from one place to another. Martens uses the following 
 terms to indicate how solid material may be brought by physical 
 means to possess the desired shape or form: (i) division: 
 the separation into different parts, as by cutting; (2) trans- 
 formation : changing the original shape without separation, as by 
 hammering; (3) agglomeration: uniting various parts into one 
 whole, as by welding. By state of aggregation is understood 
 the different conditions in which matter may exist. 
 
 Chemistry is divided into theoretical or pure, which deals with 
 the underlying laws and relations, and applied or technical which, 
 
82 CHEMISTRY 
 
 as the name implies, relates to its commercial application. It is 
 usually further divided into organic (the chemistrv of compounds 
 containing carbon) and inorganic chemistry (the chemistry of 
 compounds which do not contain carbon), but the line is not 
 sharply drawn. These again are divided into synthetic (syn- 
 thetical) and analytical (analytic) chemistry, the former having 
 to do with the building up of more complicated from less compli- 
 cated substances, while the latter deals with the determination of 
 the components of a substance. Chemical analysis indicates 
 that the analysis is by chemical methods as distinguished from 
 mechanical or microscopic methods, etc. Analytical chemistry 
 is subdivided into qualitative analysis (determining only the con- 
 stituents but not their respective percentages) and quantitative 
 analysis, where both the constituents and their respective per- 
 centages are determined. Quantitative analysis may be further 
 divided into proximate and ultimate, the former determining the 
 . percentage of the compounds of which a substance is made up, 
 while the latter determines the percentage of the elements; e.g., 
 the proximate analysis of coal (that almost always made) shows 
 the percentages of volatile matter, fixed carbon, moisture, 
 sulphur, and ash; the ultimate analysis of the same sample 
 would show the percentages of hydrogen, oxygen, carbon, nitro- 
 gen, etc. If an analysis is performed with the aid of liquid 
 solvents and reagents, it is called wet or humid analysis (process), 
 while if dry reagents and heat are employed, it is called dry 
 analysis (process), and this latter branch of chemistry, including 
 the relations of reactions to the evolution (exothremic reaction) 
 or the absorption of heat (endothermic reaction), is termed 
 thermochemistry or thermal chemistry; the corresponding 
 branch of metallurgy, thermometallurgy ; thermolysis is the 
 analysis or dissociation of a substance by the application of heat 
 alone. The analysis of ores is usuallv termed assaying, which is 
 divided into wet assaying and fire assaying. In the manufacture 
 of steel a ladle analysis is that made from drillings from a small 
 test ingot or ingots (ladle test in England termed a pit sample) 
 taken during the pouring of each melt. A finished material 
 analysis is one made on a sample of material after being rolled or 
 otherwise worked; a check analysis properly means a duplicate 
 determination to ascertain or confirm a previous result, but is 
 also commonly used in the same sense as finished material analy- 
 sis and as distinguished from a ladle analysis. A residue analy- 
 sis is one made on what remains after the other portion of a sub- 
 stance has been dissolved away the method followed in deter- 
 mining the composition of cementite after the iron matrix has 
 been dissolved. Spectrum analysis is the determination of a 
 substance or of its constituents by the color of its "flame" 
 when heated to a point of incandescence; the instrument used in 
 this work is termed a spectroscope. Microchemisrry is where 
 chemical methods are employed on minute substances or por- 
 tions of matter in conjunction with microscopical methods. In 
 some cases, particularly in the study of alloys, it is desirable 
 (owing to differences in atomic weight) to express composition 
 
CHEMISTRY 83 
 
 as atom percent instead of actual weight percent; this is arrived 
 at by a proportion between the respective percentages by weight 
 and the atomic weights, e.g.: 
 
 Weight, % Atom, % 
 
 Coppet (atomic weight, 63.5) 90 94.4 
 
 Tin (atomic weight, 118.0; 10 5.6 
 
 If the molecules of a given substance are composed of similar 
 atoms, the substance is called an element; if of two or more dif- 
 ferent kinds, a compound (chemical compound). A mechanical 
 mixture (intimate mixture) is where two or more substances are 
 in a very fine state of division, and very intimately mixed, but can 
 be separated by purely mechanical means, e.g., a mixture of iron 
 filings and powdered sulphur can be separated by the aid of a 
 magnet. A compound is said to be semi-combined when the 
 constituents are only loosely held together, as in the case of 
 water of crystallization. While atoms are too small .to be 
 measured or weighed directly, it is possible to compare their 
 properties with each other, and their relative weights are called 
 atomic weights. Formerly these weights were based on that of 
 hydrogen, the lightest atom, as i; the present standard is based 
 on a weight of 16 for oxygen as this gives numbers which are 
 somewhat easier for calculations. The molecular weight in 
 grams is called the gram molecular weight (G. M. W.) usually 
 abbreviated to molar weight or simply mole. In chemical work 
 it is frequently useful to make up what are known as standard 
 solutions which contain a definite amount of some reagent; a 
 molar solution Contains one mole of solute (dissolved substance) 
 per liter of solvent; a normal (N) solution is one which contains, 
 per liter, an amount of the substance equal to the mole divided 
 by the valence or basicity; a decinormal or tenth normal (N/io) 
 solution, for example, contains one-tenth this amount. The 
 percentage of the solute is often referred to as the concentration. 
 From Avogadro's law (see below) it is evident that a mole of any 
 gas will occupy the same volume (22.4 liters under standard 
 conditions of temperature and pressure) ; this is known as a gram- 
 molecular volume (G. M. V.) or molar volume. 
 
 There are now 83 elements recognized, but not over about 
 half are of common occurrence or application; these, together 
 with their symbols and atomic weights are listed in the accom- 
 panying table. Elements are classed as metals and non-metals, 
 while certain ones occupying an intermediate position are 
 called metalloids (of the nature of metals). Metals have a 
 bright appearance or metallic luster, at least when freshly 
 polished, and in varying degrees the properties of malleability, 
 ductility, etc., and their oxides are generally basic; the non-met- 
 als have not these physical properties, and their oxides are gener- 
 ally acid; metalloids, as a rule, resemble the metals in their 
 physical properties or, as in the case of carbon, in their ability 
 to form alloys with metals, and the non-metals in their general 
 chemical properties. Following the classification of the alche- 
 mists, metals are still referred to as noble or base (ignoble) ; the 
 
8 4 
 
 CHEMISTRY 
 
 International Atomic Weights (1917) 
 Oxygen = 16 
 
 Element 
 
 Sym- 
 bol 
 
 Atomic 
 weight 
 
 Element 
 
 Sym- 
 bol 
 
 Atomic 
 weight 
 
 Aluminium. . . 
 
 Al 
 
 27 . 1 
 
 Molybdenum . . 
 
 Mo 
 
 96 o 
 
 Antimony 
 
 Sb 
 
 I2O 2 
 
 
 Nd 
 
 
 Argon 
 
 A 
 
 39.88 
 
 Neon 
 
 Ne 
 
 20 2 
 
 Arsenic 
 
 As 
 
 74 96 
 
 Nickel 
 
 Ni 
 
 58 68 
 
 Barium 
 Bismuth 
 
 Ba 
 Bi 
 
 137-37 
 208.0 
 
 Niton (radium emanation) 
 Nitrogen 
 
 Nt 
 N 
 
 222.4 
 14 01 
 
 Boron 
 Bromine 
 Cadmium 
 Caesium 
 
 B 
 Br 
 Cd 
 Cs 
 
 II. 
 
 79.92 
 
 I I 2 . 4O 
 132.81 
 
 Osmium 
 Oxygen 
 Palladium 
 Phosphorus 
 
 Os 
 O 
 Pd 
 p 
 
 190.9 
 16.00 
 106.7 
 31 04 
 
 Calcium ' 
 Carbon 
 
 Ca 
 
 c 
 
 40.07 
 I2.OOS 
 
 Platinum 
 Potassium 
 
 Pt 
 
 K 
 
 195.2 
 39 10 
 
 Cerium 
 Chlorine 
 
 Ce 
 
 Cl 
 
 140.25 
 
 35 -46 
 
 Praseodymium 
 Radium 
 
 Pr 
 Ra 
 
 140.9 
 226 o 
 
 Chromium . . . 
 
 Cr 
 
 52 O 
 
 Rhodium.. . 
 
 Ph 
 
 102 9 
 
 Cobalt 
 
 Co 
 
 58.97 
 
 Rubidium 
 
 Rb 
 
 85 45 
 
 Columbium 
 
 Cb 
 
 93 I 
 
 Ruthenium 
 
 Ru 
 
 101 7 
 
 Copper 
 
 Cu 
 
 63.57 
 
 Samarium 
 
 Sa 
 
 150 4 
 
 Dysprosium. 
 
 Dy 
 
 162 5 
 
 Scandium . 
 
 Sc 
 
 44 I 
 
 Erbium 
 Europium. . 
 
 Er 
 Eu 
 
 167.7 
 152 o 
 
 Selenium 
 Silicon. . . . 
 
 Se 
 Si 
 
 79-2 
 28 3 
 
 Fluorine 
 Gadolinium 
 
 P 
 
 Gd 
 
 19.0 
 157 3 
 
 Silver. 
 
 Sodium . . ', . 
 
 fc 
 
 107.88 
 23 oo 
 
 Gallium 
 Germanium 
 
 Ga 
 Ge 
 
 69.9 
 72 5 
 
 Strontium 
 
 Sulphur 
 
 Sr 
 
 s 
 
 87.63 
 
 32 06 
 
 Glucinum 
 
 Gl 
 
 p.l 
 
 Tantalum 
 
 Ta 
 
 181 .5 
 
 Gold . . 
 
 Au 
 
 197 2 
 
 Tellurium . 
 
 Te 
 
 127 5 
 
 Helium 
 Holmium 
 
 He 
 Ho 
 
 4.00 
 163 5 
 
 Terbium 
 Thallium 
 
 Tb 
 Tl 
 
 159-2 
 204 o 
 
 Hydrogen 
 
 H 
 In 
 
 1.008 
 1148 
 
 Thorium 
 Thulium . 
 
 Th 
 Tm 
 
 232.4 
 1 68 5 
 
 Iodine 
 
 I 
 
 126.92 
 
 Tin 
 
 Sn 
 
 118.7 
 
 Iridium 
 
 Ir 
 
 193 I 
 
 Titanium 
 
 Ti 
 
 t8 I 
 
 Iron 
 
 Fe 
 
 55 -84 
 
 Tungsten 
 
 W 
 
 4.0 
 
 Krypton 
 
 Kr 
 
 82 92 
 
 Uranium 
 
 u 
 
 238 2 
 
 Lanthanum 
 Lead 
 
 La 
 Pb 
 
 139.0 
 207 2O 
 
 Vanadium 
 Xenon 
 
 V 
 Xe 
 
 51.0 
 
 I3O 2 
 
 Lithium 
 
 Li 
 Lu 
 
 6.94 
 175 o 
 
 Ytterbium (Neoytterbium) 
 Yttrium 
 
 Yb 
 Yt 
 
 173-5 
 
 88 7 
 
 Magnesium 
 
 Mg 
 
 24.32 
 
 Zinc ' 
 
 Zn 
 
 65 37 
 
 
 Mn 
 
 54 93 
 
 Zirconium 
 
 Zr 
 
 90 6 
 
 Mercury 
 
 Hg 
 
 200 .6 
 
 
 
 
 
 
 
 
 
 
 base metals were those which were readily dissolved by ordinary 
 acids or solvents, while the noble metals resisted all but the most 
 powerful, such as aqua regia ("royal water") a mixture of about 
 3 parts of hydrochloric acid and i part of nitric acid. 
 
 The attraction between atoms which causes them to combine 
 to form a molecule is called chemical affinity (such an aggrega- 
 tion of atoms and their mutual attraction is sometimes termed as- 
 sociation), and the cause, chemical atraction or chemical energy. 
 It is always assumed that a molecule is made up of whole atoms, 
 and not of fractions of an atom. The folio wing are the funda- 
 mental laws with regard to combinations of atoms: constant 
 proportions or definite proportions: A given compound always 
 
CHEMISTRY 85 
 
 contains the same elements combined together in the same 
 proportion by weight. Multiple proportions (Dalton's law): 
 When the same two elements combine together to form more than 
 one compound, the different weights of one of the elements which 
 unite with a constant weight of the other bear a simple ratio 
 to one another. Reciprocal proportions, or equivalent propor- 
 tions : The weights of different elements which combine sepa- 
 rately with one and the same weight of another element are either 
 the same as, or are simple multiples of, the weights of these 
 different elements which combine with each other. Gaseous 
 volumes (law of Gay-Lussac): When chemical action takes 
 place between gases, either elements or compounds, the volume 
 of the gaseous product bears a simple relation to the volumes of 
 the reacting gases. Other basic laws are: Avogadro's law: 
 Under the same conditions of temperature and* pressure, equal 
 volumes of all gases contain the same number of molecules. 
 Dulong and Pettit's law of atomic heat (only approximately 
 true): The product of the atomic weight of an element by its 
 specific heat is a constant quantity (approximately 6.4). 
 
 In 1863-64 Newlands found by arranging the elements (omit- 
 ting hydrogen) in the order of their atomic weights that there 
 was a recurring similarity in their characteristics; what is known 
 as Newlands' law of octaves is that each element closely resembles 
 the eighth element (counting the element itself as one) above or 
 below it in the scale. There is some difficulty in making out the 
 scale above chlorine (35.5), which was largely corrected by 
 Mendelejeff in 1869: Mendele Jeff's periodic law is that all the 
 properties of the elements are periodic functions of their atomic 
 weights. He was able to predict certain elements unknown 
 at the time, and to foretell with an astonishing degree of 
 accuracy what properties they would possess; which predictions 
 were notably confirmed in the cases of scandium, gallium and 
 germanium. 
 
 Isomerism. All bodies of identical molecular weight were 
 originally termed isomeric; but it is now found convenient 
 (Thorpe) to restrict this term to bodies which not only possess 
 identical molecular weights, but are also of similar chemical 
 type, and possess different physical and chemical properties. 
 Proffessor Howe proposes the following definition: Isomerism 
 is a change in the properties of a compound without change of 
 state or of ultimate composition. It is habitually accompanied 
 by a change in internal energy, and it is supposed to be due to 
 a change in the number or in the arrangement of the atoms in 
 the molecule. It is to compounds what allotropy is to elements 
 (I. A. T. M.). 
 
 Metamerism is where compounds have not only the same per- 
 centage composition but also the same molecular weight. Poly- 
 merism is a case of the same percentage composition but different 
 molecular weights. 
 
 One atom does not necessarily combine with only one other 
 atom; it may combine with several, or several of the same 
 kind may be needed to combine completely (saturate) another. 
 
86 CHEMISTRY 
 
 Hydrogen and certain other elements which have the smallest 
 combining power (valence, valency, or atomicity) have assigned to 
 them a value of i ; they are said to be monovalent or univalent 
 atoms, or simply a monad. To make this clearer it is assumed 
 that such an atom has a single bond which can become attached 
 only to a single bond of another atom. Thus, if an atom has 
 two such bonds, it can become attached to the bonds of two 
 monovalent atoms, or of one divalent atom. Valences are ex- 
 pressed as follows: 
 
 Name 
 Valence (noun) (adjective) 
 
 T monad monovalent or univalent 
 
 II dyad divalent 
 
 III , triad trivalent 
 
 IV tetrad tetravalent or quadravalent 
 
 V pentad pentavalent 
 
 VI hexad hexavalent 
 
 To avoid writing the name of an element in full each time, 
 abbreviations of the name (or the Latin or Greek name), called 
 chemical symbols, are employed. The symbol for an element 
 denotes not only the name, but also one atom, the atomic weight, 
 and all the various properties which it possesses. The composi- 
 tion of a substance or compound represented by symbols is called 
 its formula (chemical formula). Where there is more than one 
 atom of a given kind in a molecule, it is indicated by a figure 
 written just below and to the right of the chemical symbol; thus, 
 Fe2Os shows that a molecule of ferric oxide is composed of two 
 atoms of iron (Fe) and three atoms of oxygen (O). A number 
 written immediately in front of such a formula, and on the same 
 line, applies to the formula as a whole; thus, 3Fe2O 3 represents 
 three molecules. There are different kinds of chemical formula. 
 The one described above is that ordinarily referred to and is the 
 simplest; it is known specifically as an empirical or composition 
 formula. A rational or constitutional formula indicates the 
 manner in which a compound is made up; thus calcium carbonate 
 
 (CaCO 3 ) may be written CaO-CO 2 or Ca<^T>C= O. This 
 
 latter form indicates the valence of and manner of joining the 
 several atoms, and hence is termed a structural, graphic, linkage, 
 or valence formula. To indicate wherein lies the difference in 
 properties of certain compounds (isomers or stereo -isomers) 
 which have the same composition formula, it is necessary to 
 resort to three-dimension space, and hence they are termed 
 stereo-formulae; the special branch dealing with this subject is 
 termed stereo-chemistry. 
 
 Chemical Reactions. When two or more different molecules 
 are brought together, the atoms will rearrange themselves, 
 provided, under the given conditions, they have not a greater 
 affinity for the atoms with which they are already combined. 
 This rearrangement is called a reaction. A substance which, 
 when added to another, causes a reaction is called a reagent 
 
CHEMISTRY 87 
 
 (chemical reagent) ; this term is commonly restricted to certain 
 substances, such as acids and standard solutions, constantly in 
 use in a chemical laboratory, particularly those used in analytic al 
 work. The following types of reactions may occur: 
 
 1. Synthetic reaction : Where two or more differe nt substances 
 combine to form a single substance, as 
 
 SO 3 + H 2 O = H 2 SO 4 
 
 sulphur trioxide water sulphuric acid 
 
 2. Analytical reaction: Where one substance is split up (by 
 heat or otherwise) into two or more different substances, as 
 
 CaCO 3 + heat = CaO + CO 2 
 
 calcium carbonate calcium oxide carbon 
 
 (limestone) (lime) dioxide 
 
 3. Metathetical reaction: Where two or more substances 
 react to form two or more entirely different substances, as 
 
 FeS + Mn MnS ^ + Fe 
 
 iron sulphide manganese manganese sulphide iron 
 
 Catalysis is where a chemical reaction is promoted by the pr es- 
 ence of another substance (catalytic agent or catalyst) which, 
 does not itself take part directly, but remains the same through- 
 out, or is only temporarily affected. 
 
 The combining weight or chemical equivalent is the atomic 
 weight divided by the valence, e.g., 
 
 Name Atomic Weight Valence Combining Weight 
 Sodium 23 I 23 
 
 Calcium 40 II 20 
 
 The atomic volume is the value obtained when the atomic weight 
 is divided by the specific gravity. It is sometimes desired (in 
 considering volume, etc.) to ascertain what is known as the value 
 of one or more elements in terms of another; for example, the 
 carbon value of phosphorus is obtained by dividing the given 
 percentage of phosphorus by 31 (its atomic weight) and multiply- 
 ing by 12 (the atomic weight of carbon). 
 
 That portion of a molecule which enters into a chemical re- 
 action is termed a radical ; if it is a single atom, such as Ca or 
 Na, it is a simple radical ; if composed of two or more atoms, 
 acting like a simple body, such as SCU or NH4, it is a compound 
 radical. 
 
 A molecule consisting of a single atom is said to be monatomic ; 
 a molecule or a radical consisting of two 'or more atoms is poly- 
 atomic, or specifically diatomic (two), triatomic (three), tetra- 
 tomic, (four), etc. With regard to the atoms of hydrogen which 
 are replaceable in an acid by basic atoms or radicals (its basicity) 
 the terms monobasic (one), bibask or dibasic (two), tribasic 
 (three), etc., are used, or where there are two or more, the general 
 term polybasic. 
 
 A substance, usually a gaseous element, at the instant of its 
 formation, is said to be in the nascent condition, and exerts a 
 stronger action than when in its ordinary state, probably because 
 it is in its atomic and not in its molecular form. Solution 
 
88 CHEMISTRY 
 
 (chemical solution) is where one substance is dissolved or merged 
 in another without completely losing its identity, i.e., undergoing 
 a reaction whereby a new compound is formed. Thus, common 
 salt is dissolved by water, forming a solution, but it still answers 
 to the regular tests for salt, and, upon evaporating it to dryness, 
 the salt is found to be the same as before. If, while a substance 
 is in solution, another substance is added (or certain conditions 
 are changed) with which the first reacts to form a new insoluble 
 compound, the action is known as precipitation (throwing out of 
 solution,) and the insoluble compound is called a precipitate. 
 
 Compounds are ordinarily classified, according to their proper- 
 ties, into acids, bases, and a combination of the two, salts. 
 In chemistry acids are usually defined as having a sour taste, 
 having the property of turning blue litmus paper red, etc., while 
 the bases have opposite properties; but in metallurgy, acids may 
 be considered to be the oxides of the non-metallic elements, while 
 bases are the oxides of the metallic elements. A salt is neutral, 
 or either slightly acid or basic in its properties. Oxidation is the 
 name given to any process where oxygen combines with an ele- 
 ment or substance; the opposite of this, or the removal of oxygen, 
 is reduction. 
 
 The combination of two different elements is called a binary 
 compound ; of three, a ternary compound ; of four, a quaternary 
 compound, etc. In a binary compound, usually formed of a 
 metallic and a non-metallic element, the name of the latter ends 
 in -ide, thus, sodium sulphide, calcium oxide, etc. Where two 
 elements combine in more than one proportion, it is necessary to 
 indicate the ratio by giving the number of atoms of the variable 
 (in some cases of both) : 
 
 50 2 Sulphur dioxide 
 
 50 3 trioxide 
 
 S 2 O 3 sesquioxide or disulphur trioxide. 
 
 Some elements have two or even three different valences, and 
 it is essential to show which one exists in a given compound. 
 To do this, the suffixes -ous and -ic, for the lower and the higher 
 respectively, are used, and where there are more than two 
 arrangements, the prefixes hypo- for the lower and per- or hyper- 
 for the higher, are also employed. Acids are designated thus, 
 and the salts which. they form have the- suffix -ous changed to 
 -ite, and -ic changed to -ate, the prefix (if any) remaining un- 
 changed. Examples of the above are: 
 
 Acid Salt (of sodium) 
 
 Formula Name Formula Name 
 
 H 2 S 2 O 4 hyposulphurous acid Na 2 S 2 O 4 sodium hyposulphite 
 H 2 SO 3 sulphurous " Na 2 SO 3 " sulphite 
 
 H 2 SO 4 sulphuric " Na 2 SO 4 " sulphate 
 
 H 2 SO 5 persulphuric Na 2 SO 5 " persulphate 
 
 While an acid does not necessarily contain oxygen (as was at ' 
 first believed), the majority do. Those oxides which combine 
 with water to form acids are called anhydrides; thus, SO 2 , 
 sulphurous anhydride, SO 3 , sulphuric anhydride, CO 2 , carbonic 
 
CHENOT PROCESS CHESTNUT COKE 89 
 
 anhydride (also called carbonic acid, but really incorrectly), 
 etc. 
 
 Dissociation (dissociation theory is (i) the temporary decom- 
 position of a substance by the application of heat, the original 
 substance being again formed upon cooling; the temperature at 
 which this occurs is called the dissociation point. (2) In a 
 liquid or molten solution it is the separation of the dissolved 
 substance (or a part of it) into electrically positive and negative 
 particles or radicals, termed ions (ionic theory) which remain 
 loosely bound together by their mutual attraction; this is called 
 ionic or electrolytic dissociation, and the solution an electrolyte. 
 If a suitable electric current is passed through the solution, this 
 attraction is destroyed and the electronegative 'ions (anions) go 
 to the positive pole (anode) where their negative charge is neu- 
 tralized and they appear in the free state (no longer as ions); 
 similarly the electropositive ions (cations or kations) go to the 
 negative pole (cathode or kathode). This process is termed 
 electrolysis or, in the cases of a fused electrolyte, pyroelectrplysis. 
 E. D. Campbell suggests the term ionid in place of ion in the 
 case of metallic solutions. Electrolysis is based on the following 
 laws or assumptions : Faraday's laws : the amount of an electro- 
 lyte which is decomposed is proportional to the quantity (num- 
 ber of coulombs) of electricity which passes through it; (2) the 
 weight of any ion liberated by a given quantity of electricity 
 is proportional to the chemically equivalent mass of the ion. 
 The electro-chemical equivalent of an element or substance is the 
 amount set free per' coulomb of electricity. According to Arrhe- 
 nius' theory, the passage of an electric current through an elec- 
 trolyte is by means of the motion of the ions. The binary or 
 dualistic theory is that every definite compound is possessed of 
 equal amounts of positive and negative electricity. Decomposi- 
 tion is the splitting up of a compound by heat or some other 
 means; it is broader than dissociation in that decomposed com- 
 pounds need not necessarily recombine if the former conditions 
 are restored. 
 
 To indicate the purity of chemicals, various designations have 
 been adopted (as shown on the labels or elsewhere) which are 
 generally rated in the following decreasing order of excellence: 
 (a) strictly chemically pure: guaranteed to contain not over 
 . . . percent of ... (substance); (6) strictly or absolutely 
 pure; (c) chemically pure (c.p.); (d) pure; (e) commercial; (/) 
 no qualification. It should be noted that in technical writings 
 it is usually understood that only high quality substances are in- 
 tended, or else the particular grade is indicated by the context 
 or the purpose in question. 
 
 Chenot Process. See page 139. 
 
 Chernoff Process. Of treating castings: see page 62. 
 
 Cherry -red Heat. Color temperature: see page 210. 
 
 Chesterfield Process. See page 229. 
 
 Chestnut. See page 315. 
 
 Chestnut Coal. See Coal. 
 
 Chestnut Coke. See Coke. 
 
go CHILL CAST PIG CHROMOMETER 
 
 Chill Cast Pig. See page 342. 
 
 Chill Mold. See page 300. 
 
 Chill (Chilled) Roll. See page 403. 
 
 Chill Test. For charcoal iron: see page 350. 
 
 Chilled Casting. See page 58. 
 
 Chilled Heat. See Ladle. 
 
 Chipping. Employed to remove seams and other surface defects 
 occurring on billets, etc. The conditions to be observed are that 
 the depth shall not be too great, that the opening shall be flared, 
 i.e., much wider than deep, and that no sharp cuts shall occur, so 
 that after rolling or forging no laps or lap seams will result. 
 Spot Chipping.is chipping at intervals along a seam, etc., to test 
 its depth, but where the defect need not be removed by those 
 means, as when the material is to be machined. 
 
 Chipping Face ; Piece ; Strip. See page 58. 
 
 Chisel Temper. See Temper. 
 
 Chock. See page 406. 
 
 Choking. In a rolling mill with grooved rolls, overfilling a pass. 
 
 Chondrite, Chondrule, Chondrus. See page 292. 
 
 Chromate Ore. See page 244. 
 
 Chromated Steel. See page 451. 
 
 Chromatic Protection. See page 364. 
 
 Chromatic Thermometer. See page 205. 
 
 Chrome. See Chromium. 
 
 Chrome Brick. See page 398. 
 
 Chrome Iron Ore. (i) As an ore: see page 244; (2) as a refrac- 
 tory: see page 398. 
 
 Chrome Steel. See page 451. 
 
 Chromeisen. See page 352. 
 
 Chromic Iron. See page 244. 
 
 Chromite. (i) As an ore: see page 244; (2) as a refractory: see 
 page 398. 
 
 Chromium. Also called chrome; Cr; at. wt, 52; melt, pt, 1515 C. 
 (2759 F.); sp. gr., 6.92. It is not found free in nature; its chief 
 occurrence is as an oxide in combination with iron, etc., called 
 chrome iron ore (see page 244). The pure metal is hard, of a 
 steel-gray color, and is not readily oxidized. It alloys with iron 
 in all proportions, and is obtained principally as ferro-chrome 
 (see page 352). Steel of which it is a constituent is called chrome 
 steel (see page 451). It raises the saturation point of iron for 
 carbon even more powerfully than manganese does, and, like 
 manganese, prevents the separation of graphite. For influence 
 on corrosion: see page 367. 
 
 Chromium Carbide. See page 279. 
 
 Chromium Steel. See page 451. 
 
 Chromo-ferrite. See page 272. 
 
 Chromometer. An apparatus used in chemical analysis for deter- 
 mining percentages by the color method. It consists essentially 
 of two graduated tubes containing respectively solutions of the 
 standard and the test similarly treated. From the relative 
 lengths of the two columns when they have the same color, the 
 percentage is found. 
 
CHUBB'S METHOD CLOSE ANNEALING 91 
 
 Chubb's Method. Of percussive welding: see page 504. 
 
 Chuck. See page 406. 
 
 Chute. See Billet Chute. 
 
 Chute Process. See page 385. 
 
 Cinder. See Slag. 
 
 Cinder Bottom. See Lining. 
 
 Cinder Dump. A place for the disposal of waste cinder. 
 
 Cinder Fall (obs.). In an old-style blast furnace, the plate over 
 
 which the cinder runs from the cinder notch. 
 Cinder Heat. See Wash Heat. 
 Cinder Inclusion. See page 57. 
 Cinder Iron; Pig. See page 343. 
 Cinder Notch. See page 32. 
 Cinder Pit. See page 312. 
 Cinder Plate. See page 135. 
 Cinder Pocket. See page 311. 
 Cintering. Sintering. 
 
 Circular Inch. The area of a circle of i" diameter = 0.7854 sq. in. 
 Circular Mil; Circular Mil Gage. See page 187. 
 Cire Perdu Process. See page 301. 
 Cito-ductile. See page 331. 
 Clamps. (i) Of a crucible furnace: see page 114; (2) of a testing 
 
 machine: see page 469. 
 Clapp-Griffith Converter. See page 23. 
 Class. Of steel: see page 455. 
 Claudius Process. See page 368. 
 Clay. See page 396. 
 Clay Crucible. See page -in. 
 Clay Dinas Brick. See page 395. 
 Clay Ironstone (Eng.). See page 244. 
 Clay Process. See page 139. 
 
 Clayband; Clayband Ironstone (Eng.). See page 244. 
 Clean. (i) To remove the scale from a reheated piece of steel; 
 
 (2) a surface free from scale; (3) of castings: see page 58. 
 Clean Gas. See page 33. 
 Clear (verb). See page 376. 
 Clearer. See page 415. 
 
 Cleavage; Cleavage Brittleness. See page 123. 
 Cleavage Foliation. See page 124. 
 Cleavage Plane. See pages 123 and 282. 
 Cleavage Structure. See page 127. 
 Cleavage in Traces. See page 124. 
 Cleavage Weakness. Seepage 123. 
 Clemandot Process. See page 229. 
 Clinker. See Slag Cement. 
 Clinkering. See page 44. 
 Clinking (Eng.). See page 223. 
 Clinks (Eng.). Fractures (cracks) due to uneven contraction or 
 
 expansion of large masses. 
 Clinorhombic (Clinorhomboidal) System. Of crystallization : see 
 
 page 120. 
 Close Annealing. See pages 232 and 431. 
 
92 CLOSE-GRAINED IRON COAL 
 
 Close-grained Iron ; Close Iron. See page 343. 
 
 Close-jointed Skelp. See page 489. 
 
 Close Order in Line. See page 283. L 
 
 Close Pig. See page 343. 
 
 Close-top Mold. See page 299. 
 
 Closed Front. See page 32. ' 
 
 Closed Guide. See page 416. 
 
 Closed Hearth. See pages 32 and 75. 
 
 Closed Pass. See page 405. 
 
 Closed Top. (i) Of a blast furnace: see page 33; (2) of a mold: 
 see page 299. 
 
 Closer. See page 405. 
 
 Clot (Eng.). Rabble. 
 
 Clotting. The sintering or semi-fusion of ores during roasting 
 (Raymond). 
 
 Coagulation. Incipient fusion of ores which are being roasted or 
 calcined (something to be guarded against). 
 
 Coal. A stratified, combustible, carbonaceous mineral result- 
 ing from the decomposition of wood, usually accompanied by 
 heat and pressure. Coals are usually classified according to 
 (a) the amount of volatile matter they contain, and (6) the 
 purpose for which they are suitable. 
 
 Lignite or brown coal is the softest variety, somewhat resem- 
 bling peat, and is high in volatile matter and water. It is not 
 much used for metallurgical purposes. It kindles easily, has a long 
 smoky flame, low calorific power, and does not coke. Following 
 is the usual range in composition: 
 
 Volatile matter 40 to 54% 
 
 Coke 60 to 46 
 
 Fixed carbon 51 to 36 
 
 Ash i to 10 
 
 Sulphur up to 3 
 
 Moisture i to 25 
 
 A variety of brown coal, altered by faulting of igneous rocks, 
 varying in composition from that of ordinary brown coal to 
 that of anthracite, is known as glance coal. 
 
 Bituminous coals, sometimes called soft coals, are easily the 
 most important variety, as either in their natural condition, 
 or as the basis of artificial fuels, they are the kind usually em- 
 ployed for heating purposes. They burn with a yellow, lumin- 
 ous, smoky flame. If, upon distillation of the volatile matter, 
 they melt down and yield a hard, strong, coherent, carbonaceous 
 residue, they are termed coking or caking coals (rarely binding 
 coals or fat coals); otherwise, non-coking or non-caking coals 
 (rarely dry coals) . To which variety a coal belongs is determined 
 by making a practical test, as the composition or appearance is 
 not a sufficient indication. Gas coals are those which contain 
 a large amount of volatile matter, and yield up to 10,000 or 
 12,000 cubic feet of gas per ton. Cannel coal (the name is a 
 
COAL APPLES COAL FURNACE 93 
 
 corruption of "candle") is valuable for this purpose, but differs 
 somewhat in structure and appearance; the volatile matter may 
 amount to over 70%; on heating, it splits with a decided cleavage, 
 and as it emits a cracking sound, it is sometimes called parrot 
 coal. Furnace coal is any sort suitable for heating purposes, and 
 the term manufacturing coal (Eng.) is used in the same sense. 
 Forge coal or smith coal is the kind used for smiths' forges; 
 when freshly put on it is sometimes termed green coal. Bi- 
 tuminous shale is a grade containing a large amount of ash and 
 occurring in laminated masses. A coal very low in volatile mat- 
 ter is sometimes called lean or meager coal; the term is usually 
 applied relatively to bituminous coal. Splint coal is a variety 
 of non-caking coal used to a limited extent in blast furnaces 
 in Scotland. 
 
 Following is the approximate range in the composition of 
 bituminous coals: 
 
 Volatile matter 20 to 35 % 
 
 Coke 80 to 65 
 
 Fixed carbon 60 to 75 
 
 Ash i to 10 
 
 Sulphur i to 7 
 
 Moisture o to 7 
 
 Anthracite (hard coal), as found in eastern Pennsylvania, 
 is very low in volatile matter; anthracite coals (sometimes 
 termed anthracite in England) are usually somewhat higher 
 in volatile matter. This variety is hard to ignite, and it burns 
 with very little flame. Its composition is approximately: 
 
 Volatile matter 3 to 7% 
 
 Fixed carbon 85 to 90 
 
 Ash 3 to 7 
 
 Sulphur up to i . 5 
 
 Moisture o to 4 
 
 Occasionally specimens of anthracite are found in spheroidal 
 masses, termed coal apples. 
 
 Coal as mined, occurring in large and small lumps, is called 
 run-of-mine coal. After washing and crushing, it is sorted 
 into sizes which receive various names (according to their size) 
 such as buckwheat, pea, and chestnut or nut. The fine material 
 containing a little dirt, which is removed from the larger pieces 
 by screening, is termed slack. In the anthracite regions, such 
 coal thrown on the dump is called culm. 
 
 Pit coal is an old English name for mined coal (in contra- 
 distinction to charcoal) ; if transported on vessels, it was known 
 as sea coal. Coal high in sulphur is sometimes called sulphur 
 coal or stinking coal. 
 
 Coal Apples. See Coal. 
 
 Coal Furnace. See pages 39 and 181. 
 
94 COAL GAS COIL 
 
 Coal Gas. The gas obtained by the distillation of bituminous 
 coal in closed retorts, and used principally for illuminating 
 purposes. 
 
 Sexton gives an average analysis (by volume) as: 
 
 Hydrogen . . : 48% 
 
 Carbon monoxide 8 
 
 Methane 36 
 
 Ethylene 3.8 
 
 Non-combustible 4.2 
 
 Coalescence. See page 120. 
 
 Coalite. A trade name for a product obtained by filling flat rec- 
 tangular retorts with bituminous coal, and heating vertically in a 
 gas-fired furnace at 800 F. (425 C.), the coal swelling, and the 
 resulting pressure giving good density to the product. It resem- 
 bles coke in appearance, but is higher in volatile matter, and 
 its calorific power is stated to be close to that. of coal; it is also 
 claimed to be smokeless. 
 
 Coarse-grained Fracture. See page 178. 
 
 Coating. (i) For protection: see page 370; (2) in wire drawing: 
 see page 507. 
 
 Cobalt. Co; at. wt, 59; melt, pt., 1464 C. (2667 F.); sp. gr., 
 8.72. It is not found in the uncombined state, and is usually 
 associated with nickel. It is a hard white metal having a slight 
 bluish tinge. For influence on corrosion : see page 366. 
 
 Cobalt Steels. See page 453. 
 
 Cobbing. See Ore. 
 
 Cobble. (i) In puddling: see page 377; (2) in rolling: see page 
 
 4i5. 
 
 Cod. See page 299. 
 Coddle. Of blast: see page 35. 
 Codonoid. See page 290. 
 Codorus (obs.). Or silicon ore: a silicious iron ore formerly 
 
 sometimes used in puddling. 
 Coefficient of Corrosion. See page 108. 
 Coefficient of Distribution. See Solution. 
 Coefficient of Elasticity. See page 334. 
 Coefficient of Impact. See page 481. 
 Coefficient of Restitution. See page 478. 
 Coffee-mill Squeezer. See page 377. 
 Coffin Bend. See page 265. 
 Coffin Joint; Weld. See page 503. 
 Coffin Process. For axles and rails: see page 233. 
 Cogging. See pages 115 and 407. 
 Cogging Hammer. See Hammer. 
 Cogging Mill. See page 411. 
 Cohenite. See page 292. 
 Cohesion. See page 81. 
 Coil. A roll or bundle of wire, hoop, etc., made'up in this form for 
 
 convenience in handling and shipping. If the^material is bent 
 
COKE 95 
 
 backward on itself, like a flattened letter "S," it is called a 
 scroll bundle or hoop. If one length is wound up on itself, like 
 a clock spring, it is known as a single coil or single strand (strip) 
 coil; if several lengths are thus wound up simultaneously, a 
 standard or regular coil ; continuous coils are made up of several 
 strips, one being coiled up before the next is put on, with a short 
 lap, so that one length can be used without disturbing the re- 
 mainder of the coil. Coils are sometimes called strips. A hank 
 is a bundle of wire; a stone is a name rarely applied to a bundle 
 of small wire weighing about 12 pounds. The term stone wire 
 is usually applied to fine wire suitable for wire cloth and similar 
 purposes. 
 
 Coke. Grade of tin plate: see page 433. 
 
 Coke. (i) The residue obtained by driving off all, or nearly all, 
 the volatile matter from solid or liquid fuels; (2) as generally 
 understood, such residue obtained from certain kinds of bitumi- 
 nous coals, which is hard, strong and porous, and hence can 
 support a heavy burden without crushing. This latter is par- 
 ticularly valuable for heating by contact, as it has practically no 
 flame. As its specific gravity is about 0.9, while that of carbon 
 is 2, over 50% of its volume must be air space which enables it 
 to burn more readily. It is stated (Bull. No. 382, U. S. Geol. 
 Sur.) that the coking properties of a coal are determined by the 
 ratio of hydrogen to oxygen in the composition of the coal. 
 Experiments indicated that with H:O over .50% it will coke. 
 Practical tests should, however, be made. 
 
 An average analysis of Connellsville coke, and the coal from 
 which it is made, is as follows: 
 
 Coke, % Coal, % 
 
 Moisture 1.33 
 
 Volatile matter 1.50 28.36 
 
 Fixed carbon 88 . oo 62.64. 
 
 Sulphur 0.90 i. in 
 
 Phosphorus 0.077 0.013 
 
 Ash 10.50 7.68 
 
 At the present time coke is made in either beehive or retort 
 ovens, the product being termed, respectively, beehive coke, 
 and retort coke or by-product coke. 
 
 Beehive ovens are of the shape which their name indicates, 
 and are built either in a single row against a hillside (bank ovens), 
 or in a double row back to back (block ovens). They are of fire- 
 brick, faced with stone, and each has an opening in the top for 
 charging (trunnel head) and another at the bottom for drawing 
 (door). They are usually 10^ to 12 feet in diameter. The charge 
 amounts to about 4^ tons for forty-eight hour coke, and 6 tons 
 for seventy -two hour coke, these two names indicating the length 
 of time required for the operation. After dumping in the ovens, 
 the coal is leveled off, and the door bricked up except for small 
 openings to admit the air for combustion. The oven, hot from a 
 previous charge, or heated with fuel, causes the volatile matter to 
 
96 COKE 
 
 be driven off; this burns and supplies the requisite amount of 
 heat; the coking proceeds from the top downward. When the 
 process is complete, the red-hot mass is quenched with water, 
 broken up and removed from the oven either by hand with rabbles 
 or by a machine termed a coke extractor or coke pusher. 
 Properly burned coke usually has a whitish deposit extending 
 downward from the top a couple of inches, called whiskers, which 
 is supposed to be an indication of its good quality. 
 
 In retort ovens the coal is placed in vertical, or horizontal, 
 closed brick chambers externally heated by flues. The volatile 
 matter consisting of hydrocarbons, tar, and ammonia is saved, 
 for which reason this type is known as a by-product oven. 
 The by-product recovery operation is briefly as follows (Meissner, 
 Am. I. & S. Inst., 1913): In the indirect process (indirect re- 
 covery process) the gas leaves the ovens through the foul gas 
 main, located above the ovens, and is taken to the by-product 
 plant where it is cooled, the tar extracted, the naphthalene thrown 
 down as far as possible, and the ammonia scrubbed out of the gas 
 by passing through water towers or other apparatus. The 
 weak ammonia liquor is passed into lead-lined saturators con- 
 taining sulphuric acid, and ammonium sulphate formed, or the 
 distilled ammonia is placed in tanks and shipped as strong ammo- 
 nia liquor. In the direct recovery process the scrubbing of the 
 ammonia from the gases is avoided by passing them through 
 the saturator after the separation of the tar. In some of the so- 
 called direct processes tar is separated by cooling the gases, and 
 in this case a certain proportion of ammonia is precipitated with 
 the tar and must be distilled. In others, tar is separated without 
 the precipitation of ammonium salts. These latter are more 
 properly called direct than those where some of the am- 
 monia is precipitated, which should be called semi-direct proc- 
 esses. The thio -sulphate process is the name usually given to 
 a process for utilizing the sulphur contained in the gases; e.g., 
 in the Burkheiser process a special oxide purifier removes hydro- 
 gen sulphide from the gas and employs it to make an acid solu- 
 tion for the recovery of ammonia as sulphate and sulphite. 
 Where the surplus gas (after extraction of the by-products and 
 the heating of the retorts) is used for generating power, it is 
 called a waste heat oven ; otherwise, where gas is sold, as much as 
 possible is generally desired for that purpose. 
 
 Foundry coke. This coke is selected from ovens which have 
 burned 72 liours. It is always made on Mondays and Tuesdays, 
 as no work is done at the ovens on Sundays. It may be made on 
 other days of the week by shutting down another day. ; It is 
 hard and large, and has a bright appearance caused by the carbon 
 condensing on the surface. This coke is used in cupolas for 
 melting iron, and also for heavy forging work. 
 
 Furnace coke (blast furnace coke). This is coke that is 
 burned 48 hours, and is used in smelting ores in blast furnaces. 
 It is sometimes used in cupola practice. 
 
 Standard foundry and furnace coke. Sulphur under i%: 
 the lower the better. Ash not over 13%; the quality improves 
 
COKE BARS COLD BENDING 97 
 
 with the reduction in ash until the percentage is brought to a 
 point where the structure is weakened. 
 
 Smelter coke is either of the above running, say, over 1.20% 
 in sulphur. While this higher sulphur renders it undesirable 
 for smelting or melting iron, it does not harm it for the smelting 
 of most other non-ferrous ores. 
 
 Stock coke is that stocked on the oven yard instead of being 
 loaded direct into cars. If care is used in selecting, when loading, 
 it is as good as if freshly drawn, with the exception that it is 
 somewhat broken up by the double handling, and is discolored. 
 Soft coke, heating coke, or jamb coke is the cullings from 
 the above classes, and is made up of the backs, fronts, and that 
 around the oven doors; this is often incorrectly called stock coke. 
 Crushed coke is crushed and graded according to size into the 
 following classes: egg, large stove, small stove, chestnut, %-inch 
 pea, ^2-inch pea, dust coke, coke dust, or coke breeze. The 
 first four grades are used for house heating, small forgings, etc., 
 the pea size for chemical works, etc., and the dust for covering the 
 bottoms of soaking pits and crucible furnaces to protect the 
 brick-work from melted scale. 
 
 The coke obtained as a by-product from the distillation of 
 coal for illuminating gas is called gas coke or gas-house coke. 
 It is very hard, and is largely used for electric light carbons 
 and the electrodes of electric furnaces, for which purposes it 
 is ground, mixed with a little tar, molded and heated. Retarded 
 coke is coke which has been mixed with milk of lime or other inert 
 substance to reduce the rate of combustion. 
 
 The Diehl-Faber process consists in introducing limestone into 
 a charge of raw coal containing sulphur. It was claimed that 
 calcium sulphide was formed during coking, and that the phys- 
 ical properties of the product, termed neutral coke, were much 
 improved. 
 
 Coke Bars. See page 411. 
 
 Coke Bottom. See Lining. 
 
 Coke Breeze ; Dust. See above. 
 
 Coke Extractor. See page 96. 
 
 Coke Finery. See page 383. 
 
 Coke Furnace. See pages 39 and 181. 
 
 Coke Hole. See page 114. 
 
 Coke Malleable. See page 346. 
 
 Coke Ovens. See page 95. 
 
 Coke Pig. See page 343. 
 
 Coke Plate. See page 433. 
 
 Coke Pusher. See page 96. 
 
 Coke Refinery. See page 383. 
 
 Coke Sheet. See page 433. 
 
 Coke Tin; Tin Plate. See page 433. 
 
 Coking Coal. See Coal. 
 
 Colander Funnel. See page 60. 
 
 Colby Furnace. See page 154. 
 
 Cold Bend Test. See page 476. 
 
 Cold Bending. See Cold Working. 
 7 
 
98 COLD BLAST COLD WORKING 
 
 Cold Blast. See Blast. 
 
 Cold Blast Charcoal Iron. See page 343. 
 
 Cold Blast Cupola. See page 182. 
 
 Cold Blast Furnace. See page 39. 
 
 Cold Blast Iron. Pig iron smelted with a cold blast. 
 
 Cold Blowing Iron, Metal, Pig. See page 20. 
 
 Cold Bottom. See page 376. 
 
 Cold Cracks. See page 223. 
 
 Cold Crystallization. See page 179. 
 
 Cold Cupping; Dishing. See Cold Working. 
 
 Cold Distortion. See Cold Working. 
 
 Cold Drawing. (i) General: see page 101; (2) of tubes: see 
 page 49 2 j (3) of wire: see page 507. 
 
 Cold Ductility. See page 331. 
 
 Cold Etching. See page 286. 
 
 Cold Flanging. See Cold Working. 
 
 Cold Galvanizing. See page 371. 
 
 Cold Hammering. See Cold Working. 
 
 Cold Hanging. See page 35. 
 
 Cold Iron; Metal; Pig. (i) In foundry work, cast iron which is 
 thick and sluggish and does not pour readily on account of being 
 at too low a temperature; (2) cast iron at a low temperature in 
 the blast furnace and hence usually higher in sulphur than normal; 
 see page 343 ; (3) in Bessemer practice iron which is low in silicon : 
 see page 20. 
 
 Cold Junction. See page 209. 
 
 Cold Lap. See Seam. 
 
 Cold Pot. See page 432. 
 
 Cold Pressing. See Cold Working. 
 
 Cold Punching. See Cold Working. 
 
 Cold Rolls. See page 431. 
 
 Cold Rolling. See pages 101 and 431. 
 
 Cold Saw. A circular power saw for cutting metals while cold. 
 
 Cold Scaffold. See page 35. 
 
 Cold Set. Of metal: chilling. 
 
 Cold Shearing. See Cold Working. 
 
 Cold Short; Shortness. See Brittleness. 
 
 Cold Short Ore. See page 243. 
 
 Cold Shut. (i) The freezing over of the top surface of an ingot 
 before the mold has been filled, due to an interruption of the 
 stream of metal; this is most likely to happen in the crucible 
 process (see page 115), or where very small ingots are made; (2) 
 the name for certain defects: see pages 426 and 502; (3) a special 
 link for repairing broken chains which is closed up cold; it must 
 not be confused with (i) or (2). 
 
 Cold Stable State. See page 327. 
 
 Cold Straining. See Cold Working. 
 
 Cold Twisting. See Cold Working. 
 
 Cold Wild. Wildness due to the temperature of the steel having 
 been too low for the purifying reactions to take place; perhaps 
 on account of infusibility of the metal due to oxides. 
 
 Cold Working. Straining metal cold (cold straining) beyond its 
 
COLD WORKING 99 
 
 elastic limit with a corresponding effect upon the physical 
 properties; this is the same as plastic deformation (see Metallog- 
 raphy, p. 281) and overstrain (see Physical Properties, p. 334). 
 Depending upon its nature, and upon the further use or treatment 
 of the material, it may be beneficial or harmful. The effect is 
 due to the permanent deformation of the crystals or grains from 
 their normal shape which, on account of the rigidity of the mate- 
 rial when cold, they can completely regain only by annealing 
 (see Heat Treatment, p. 231), which restores the original proper- 
 ties if the cold working has not been excessive. If the cold 
 working has been unequal, this leads to severe internal strains 
 which may develop so-called season cracks (occurring sometimes 
 years afterward), or may cause cracking on annealing, owing to 
 the different rates of recrystallization in the portions differently 
 strained. If the cold working has been excessive (overwork), 
 spontaneous cracking may result; in the case of bars this may 
 take the form of splitting or flaking, and in the case of sheets 
 exfoliation may result, thin layers peeling off or crumbling away. 
 Rosenhain states that as a general rule cold working may be con- 
 tinued without permanent damage as long as the tensile strength 
 continues to rise. "When this strain hardness is merely to 
 afford stiffness and does not involve the general question of 
 resistance to serious and continued stresses, it is perfectly log- 
 ical and rational. In some cases, particularly wire, the artificially 
 induced strength appears more or less permanently reliable, 
 although with wire ropes subjected to repeated bending, fatigue 
 failures occur, as against alternating stresses strain hardness is 
 of no avail. This is more serious with rods of hard-drawn or 
 cold-drawn alloys employed for bolts or where called on to carry 
 important loads. Practical experience in such cases confirms 
 conclusions drawn from research data that the extra strength 
 from strain hardness cannot be safely relied upon for continued 
 resistance, particularly where stresses are alternating or intermit- 
 tent. The best recent practice shows a strong and highly rational 
 tendency to avoid the use of any material which has been severely 
 cold-worked, unless subsequently annealed to remove strain 
 hardening more or less completely" (Rosenhain). As opposed 
 to this statement of Rosenhain's may be cited the use of hard- 
 drawn wire for cables, etc., and the data in the following table 
 offers evidence that a careful distinction must be made between 
 cold -drawn and cold -rolled material when subjected to repeated 
 transverse stresses (see next page). 
 
 Heyn states that since cold rolling and cold hammering are apt to 
 produce tension strains in the core, whereas cold drawing, on the 
 contrary, causes tension strains in the superficial layers, it is 
 possible to reduce strains by alternating these processes. This 
 difference would also serve to account for the results in the table. 
 As regards electrical and magnetic properties, cold working 
 decreases the magnetic permeability and the remanence and in- 
 creases the coercive force and the resistance. The solubility in 
 acids is increased but the specific heat does not appear to be 
 affected. 
 
100 
 
 COLD WORKING 
 
 
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COLD WORKING IOI 
 
 Cold working usually consists in (a) slightly reducing the 
 cross-sectional area by rolling, hammering or drawing; (b) 
 distorting the material by bending, flanging, cupping or twisting; 
 and (c) punching or shearing. 
 
 Cold rolling, cold hammering, and cold drawing are employed 
 for one or more of the following reasons: (a) the effect upon the 
 physical properties; (b) where extreme accuracy as to size is 
 required; (c) to obtain a very smooth, even surface; (d) in the case 
 of cold drawing, to produce certain thin, complicated sections, 
 such as cornice molding, which could hardly be obtained commer- 
 cially by any other method. The hole in a die through which 
 material is drawn is frequently called the reduction ring. The 
 material (usually round, square or hexagon bars) is first pickled to 
 remove all the scale. Round bars for shafting, etc., are made 
 perfectly straight after rolling by passing them through a revolv- 
 ing straightening machine called a flyer. A curious action takes 
 place in this machine: open hearth steel bars, over about 0.15 % 
 carbon are increased slightly in diameter (swelling), while those 
 of Bessemer steel, not over 0.10% carbon are reduced slightly 
 (shrinking). The reduction is very slight on account of the 
 resistance of the material to being worked, and the very much 
 higher cost in comparison with hot working; an exception to 
 this is wire drawing (see Wire). 
 
 In drawing large rounds, say over 3" in diameter, breakage 
 sometimes occurs from too heavy reduction without proper 
 annealing. With such large 'sizes, the outside is worked more 
 than the interior, producing a skin or shell around an inner core. 
 Sometimes only this shell is broken, called skin breakage or 
 shelling. 
 
 By cold working the tensile strength may be increased about 
 20 to 40%, and the elastic limit 60 to over 100%. 
 
 Cold twisting is applied to certain bars, to be used in reinforced 
 concrete construction, to increase their elastic limit (about the 
 same as by cold rolling) and also to afford better bonding with the 
 concrete. Cold bending and cold pressing (cupping, dishing and 
 flanging) are resorted to more to obtain some desired form; 
 also to obtain greater stiffness, but rather from this form than 
 from any effect on the metal due to the cold working involved. 
 An application of cold working made use of by bell hangers to 
 increase the elastic limit of the wire is known as frigo -tension. 
 It consists in subjecting the metal to repeated tensile stresses 
 somewhat above the elastic limit. 
 
 Cold shearing and cold punching affect the metal to a slight 
 depth (about }>{Q to %" or even more) from the sheared or 
 punched surface, the effect being proportional to the thickness of 
 the piece and to its percentage of carbon or other hardening 
 elements. This is liable to cause cracking if the piece is bent 
 across a sheared edge or where there is a punched hole, the danger 
 being much greater if the upper surface (the entering side for 
 the punch or the shear blade) is on the outside of the bend, 
 probably due to the fin on the lower side, and also to the fact that 
 at the upper side the affected metal is in compression. This 
 
102 COLE- COMMON LINES 
 
 effect may be removed by aaoealing or by machining off the 
 
 embrittled portion. First punching a small hole and then ream- 
 ing it out to the desired size is known as sub-punching. 
 
 Machining is "essentially the action of an edged cutting tool 
 and consists in bringing to bear upon a very small area of metal 
 a stress sufficiently intense to produce rupture. Obviously, 
 however, although actual rupture is confined to a single line or 
 surface, severe strain will be produced in the immediate vicinity, 
 so that in an ordinary machined or filed surface the visible grooves 
 are accompanied by corresponding sub-surface regions of strained 
 material. This region will be deeper, the deeper the "cut" 
 which has been taken and the greater the force which has been 
 employed, and also the blunter the tool, i.e., the larger the area 
 to which the intense pressure of the tool has been applied." 
 With a grinding wheel or with emery paper the cutting is ex- 
 ceedingly sharp and the depth is very slight (Rosenhain). 
 
 Cole (obs.). Coal. 
 
 Collar. See page 404. 
 
 Collaring. See page 415. 
 
 Collins (W. W.) Process. See page 380. 
 
 Collodion Coating. See page 365. 
 
 Colloid. See Solution. 
 
 Colloidal Metal. See page 128. 
 
 Colony. See page 123. 
 
 Color Carbon. See Carbon. 
 
 Color Identity; Names; Scale. Of temperatures: see page 210. 
 
 Column. See page 468. 
 
 Columnar Crystals. See page 125. 
 
 Columnar Fracture. See page 1 78. 
 
 Columnar Granulation, Structure. See page 125. 
 
 Comb. See page 291. 
 
 Combination Induction Furnace. See page 153. 
 
 Combination Pot. See page 432. 
 
 Combination Steel. See page 443. 
 
 Combination, Water of. See Water. 
 
 Combined Arc and Resistance Furnaces. See page 153. 
 
 Combined Carbon. See Carbon. 
 
 Combined Carbon Dioxide. See page 107. 
 
 Combined Water. See Water. . 
 
 Combining Weight. See page 87. 
 
 Combustible Matter. See Fuel. 
 
 Combustion. See page 202. 
 
 Combustion Carbon. See Carbon. 
 
 Comby. See Pit. 
 
 Come to Nature. See page 376. 
 
 Commercial Annealing. See page 231. 
 
 Commercial Elastic Limit. See page 470. 
 
 Commercial Ore. See page 243. 
 
 Comminute. To bring to an extremely fine state of division. 
 
 Common Calorie. See page 199. 
 
 Common Iron. See page 379. 
 
 Common Lines, Of deformation: see page 283. 
 
COMPACT GRAINED- CONGEALED SOLUTION 103 
 
 Compact Grained Pig Iron. Pig iron whose fracture shows fine 
 
 grains or crystals. 
 Comparator. See page 483. 
 Complete Combustion. See page 202. 
 Complete Corrosion. See page 106. 
 Complete Crystal. See page 122. 
 
 Complete Fusion, Zone of. In blast furnace practice : see page 36. 
 Complete Heterogeneous Equilibrium. See page 327. 
 Compo. See page 64. 
 Component. See page 326. 
 Composite Casting. See page 64. - 
 Composite Fracture. See page 179. 
 Composition Face. See page 1 24. 
 Composition Formula. See page 86. 
 Compound. Chemical compound: see page 83. 
 Compound Armor Plate. See page 8. 
 Compound Casting. See page 64. 
 Compound Cell. See page 121. 
 Compound Couple. See page 209. 
 Compound Crystal. See page 124. 
 Compound Cupola. See page 182. 
 Compound Gas. See page 33. 
 Compound Ingot. See page 64. 
 Compound Microscope. See page 285. 
 Compound Radical. See page 87. 
 Compound Steel. (i) Steel made by casting layers of hard and soft 
 
 material together: see page 64; (2) alloy steel: see page 443; 
 
 (3) a name rarely given to steel made by the duplex process: see 
 
 page 317. 
 
 Compound Stress. See page 332. 
 Compound Twin. See page 124. 
 Compression. See page 336. 
 Compression Figure. See page 126. 
 Compression Test. See page 476. 
 
 Compression Hardened (Tempered) Steel. See page 229. 
 Compression Theory. Of hardening: see page 280. 
 Compression by Wire Drawing. See page 64. 
 Compressive Resilience. See page 331. 
 
 Compressive Strain; Strength; Stress. See pages 330 and 332. 
 Compressometer. See page 476. 
 Concentrated Load. See page 468. 
 Concentration. Percentage composition: see page 83. 
 Concentric Converter. See page 17. 
 Concentric Load. See page 332. 
 Conchoidal Fracture. See page 178. 
 Conduction. See page 200. 
 Conductometer. See page 483. 
 Cone, Fusible. See page 209. 
 Cone Test. For hardness: see page 478. 
 Cone Washer. See Ore. 
 Configuration. See page 126. 
 Congealed Solution. See page 270. 
 
104 CONGENITAL MALLEABLENESS CONVECTION 
 
 Congenital Malleableness. Malleable as produced. 
 
 Congenital Twin. See page 1 24. 
 
 Conglomerate Structure. See page 125. 
 
 Congreayes' Composite Steel. See pag'e 64. 
 
 Congredient (Tiemann). Suggested as a general term to include 
 
 elements, impurities, or constituents of a substance. 
 Congruent Freezing. See page 267. 
 Conley-Lancaster Process. See page 140. 
 Conley Process. (i) Direct: see page 140; (2) electric: see page 
 
 155- 
 
 Conoid. See page 290. 
 
 Consolute (rare). Miscible in all proportions. 
 Constant Angles. Law of: see page 120. 
 Constant Heat Sums. Law of: see page 201. 
 Constant Pressure Thermometer. See page 205. 
 Constant Proportions. Law of : see page 84. 
 Constant Sum Theory. Of passivity: see page 364. 
 Constant Volume Thermometer. See page 205. 
 Constantan. See page 209. 
 Constituent. See pages 264 and 326. 
 Constituents of Iron Alloys. See page 272. 
 Constitution of Special Steels. See page 444. 
 Constitutional Diagram. See page 271. 
 Constitutional Formula. See page 86. 
 Constitutive Freedom, Degree of. See page 327. 
 Contact, Angle of. See page 407. 
 
 Contact Confusion of Orientation. See pages 127 and 282. 
 Contact Heating Furnace. See page 181. 
 Contact Twin. See page 124. 
 Contact Welding. See page 503. 
 Continuous Acting Press. See Press. 
 Continuous Beam. See page 468. 
 Continuous Coil. See Coil. 
 Continuous Combustion. See page 202. 
 Continuous Curve. See Curve. 
 Continuous Furnace. See page 184. 
 Continuous Galvanizing Process. See page 509. 
 Continuous Heating Furnace. See page 184. 
 Continuous High Bloomary. See page 144. 
 Continuous Mill. See page 412. 
 Continuous Producer. See Producer. 
 Continuous Stuckofen. See page 142. 
 Contracting Chill. See page 300. 
 Contraction. See page 204. 
 Contraction of Area. See page 336. 
 Contraction Cavity. See page 53. 
 Contraction Crack. See Crack. 
 Contraction Pyrometer. See page 209. 
 Contraction Pyroscope, Wedgwood's. See page 209. 
 Contraction Rule. See page 296. 
 Contraction of Section. See page 336. 
 Convection. See page 200. 
 
CONVERSION COPPER STEEL 105 
 
 Conversion. See page 81. 
 
 Conversion Process. Where a desired change in the properties 
 are effected by purification, as of cast iron into steel. 
 
 Converted Bar. See page 71. 
 
 Converted Gray Castings. A grade between gray and malleable 
 castings, obtained by heating white cast iron to about 1010 C. 
 (1850 F.) for a few hours. 
 
 Converted Steel. Blister steel: see page 71. 
 
 Converter. See page 15. 
 
 Converter Steel (rare). Bessemer steel. 
 
 Converting Furnace. Cementing furnace: see page 70. 
 
 Converting Pot. See page 70. 
 
 Converting Process. (i) Bessemer process; (2) cementation 
 process. 
 
 Convex Pass. See page 405. 
 
 Cooling. (i) General: see page 227; (2) law of: see page 200. 
 
 Cooling Bed. See page 414. 
 
 Cooling Crack. See Crack. 
 
 Cooling Curve. See pages 129 and 267. 
 
 Cooling Curve Method. Of determining critical points: see page 
 265. 
 
 Cooling Plate. See page 27. 
 
 Cooling of Solid Solutions. See page 270. 
 
 Cooling Table. See page 414. 
 
 Cooper Process. See page 140. 
 
 Coordinate. See Curve. 
 
 Cope. See page. 297. 
 
 Copper. Cu; at. wt., 63.6; melt, pt., 1050 C. (1922 F.); sp. gr., 
 electrolytic, 8.945, hammered, 8.95. It is found both free and 
 combined. It is a reddish-colored metal, very malleable and 
 ductile, possessed of great tenacity, and is one of the best conduc- 
 tors for both heat and electricity. Its occurrence in steel usually 
 results only from its presence in the ores (see also page 371). Up 
 to at least 0.5% it does not seem to have any bad effect upon 
 steel, but with i %, in conjunction with high sulphur, it may 
 cause some red shortness; it tends to hinder welding. 
 In amounts up to 0.5% (commonly o.io to 0.30%) it has re- 
 cently come into extensive use in the manufacture of steel, 
 particularly thin sheets and ordinary plates owing to its effect 
 in greatly reducing corrosion (q.v., page 366). In these amounts 
 and even up to 1.00% (unless perhaps when accompanied by 
 abnormally high sulphur) its effect on the physical properties 
 appears to be a slight increase in the elastic limit and the tensile 
 strength with, if anything, a little better ductility; with heavy 
 plates it somewhat resembles nickel in preventing as good a 
 surface as usual. For influence on corrosion: see page 366. 
 
 Copper-clad Steel. See page 372. 
 
 Copper Coating. (i) For protection against corrosion: same as 
 plating: see page 371; (2) in wire drawing: see page 508. 
 
 Copper Plating. See page 371. 
 Copper Pyrites. See page 245. 
 Copper Steel. See pages 372 and 453. 
 
106 ' [", COPPERAS CORROSION 
 
 Copperas. See page 245. 
 
 Coppered Steel. See page 508. 
 
 Coppered Wire. See page 508. 
 
 Copperizing (rare). Coating with copper. 
 
 Core. (i) In case hardening: see page 67; (2) in molding: see 
 page 299. 
 
 Core Bar; Barrel; Binder ; Box. See page 299. 
 
 Core Cemented ; Cementation. See page 67. 
 
 Core Gum ; Nail ; Plate; Print. See page 299. 
 
 Core Steel. See Edge Steel. 
 
 Cored Structure. See page 125. 
 
 Corey Reforging Process. See page 8. 
 
 Coring. See page 299. 
 
 Corroding Agents. See page 107. 
 
 Corrosion. (See also Protection, page 365). The slow oxida- 
 tion and wasting away of metal, usually at ordinary tempera- 
 tures; it may also be extended in meaning to cover the more 
 rapid action at high temperatures, generally called oxidation or 
 scaling, also loss resulting from other chemical reactions either 
 at ordinary or high temperatures. (Contrast with erosion, the 
 loss occurring in gun barrels when a film on the surface is melted by 
 the temperature generated in the explosion of the powder and 
 blown out by the force of the gases generated; and abrasion, 
 the mechanical removal of particles by the rubbing action of 
 another substance.) Its commonest manifestation is rust 
 which is the oxide of iron formed on the surface of corroded iron. 
 Dr. Rideal has defined corrosion as follows: " Corrosion may be 
 said to result from an irreversible chemical change proceeding 
 with a small velocity and taking place on the common surfaces 
 between two or more phases, the products of which change are 
 continually removed from the sphere of action." 
 
 Different types of corrosion may be classified as follows: 
 (Some of the following definitions were devised particularly for 
 non-ferrous alloys, but also apply to steel alloys). Complete 
 corrosion (Corrosion Comm., Inst. Met., 1916) in which both 
 constituents of the alloy dissolve at approximately the same rate 
 and uniformly over the surface of the metal. Selective corrosion 
 (Cor. Comm.) in which only one constituent dissolves. In the 
 case of a brass it is usually the zinc that dissolves selectively, a 
 process termed dezincification. Distinction should also be 
 made between general selective corrosion, which occurs over the 
 whole surface uniformly, and localized selective corrosion, 
 which occurs in spots, also called pitting or tubercular corrosion ; 
 of this last type is also the case where pipes or other objects of 
 cast iron are long subjected to corrosive action, such as guns sunk 
 for a century in sea water, termed graphitic corrosion, graphiti- 
 zation, sponge-like decay or iron cancer, the surfaces being ap- 
 parently sound but are readily penetrated by a sharp-pointed 
 instrument and in place of the original metallic substance is 
 found a mass of oxide of iron mixed with flakes of graphite. 
 Corrosion occurs when iron is exposed to moist air or to water 
 
CORROSION 107 
 
 containing acids or certain substances (corroding agents). The 
 ratio of the corrosion produced by a given set of conditions to that 
 of pure water is termed the corrosion factor. In order to agitate 
 a solution as well as introduce oxygen in making corrosion tests a 
 jet of air is sometimes employed. The Corrosion Committee of 
 the Institute of Metals recognizes two kinds of aeration : gentle 
 aeration in which the mechanical agitation of the water or solu- 
 tion by the stream of air is reduced to a minimum; and violent 
 aeration, in which the air impinges directly upon the surface of 
 the metal, or in any other way produces considerable agitation 
 of the liquid which is in immediate contact with the metal. 
 
 According to the carbonic acid theory this gas must be present. 
 It is pointed out by Gibbs that sea water from which all carbon 
 dioxide has been removed is alkaline because it contains an excess 
 of basic over acid substances. In contact with air this alkaline 
 solution will absorb carbon dioxide until its alkalinity is neutral- 
 ized. The solution will then be neutral. At this stage all car- 
 bonic acid in sea water will be present in chemical equilibrium 
 with the dissolved salts. This is the combined carbon dioxide. 
 It might be called chemically dissolved carbon dioxide. The 
 atmosphere contains free carbon dioxide, consequently it would 
 continue to dissolve in this neutralized sea water until equilibrium 
 is established between the sea water and the atmosphere. This 
 small additional quantity of carbon dioxide is physically dissolved 
 in the sea water and is known as the free carbon dioxide. 
 
 The acid theory of corrosion "depends on the simultaneous 
 presence of oxygen, moisture, and an acid, and mere traces of 
 acidity are sufficient to start the reaction. As generally under- 
 stood, the primary attack is due to carbonic acid, a ferrous salt 
 resulting, which in turn is acted upon by oxygen and water with 
 the formation of rust and the liberation of the acid. In this 
 manner the process is continuous, and a comparatively small 
 amount of acid may exercise a vast influence" (Longmuir). 
 
 Since, as previously stated, corrosion is a slow process, various 
 methods of testing have been suggested to expedite matters and 
 thereby obviate tedious delays by intensifying conditions. Such 
 accelerated tests are frequently of value as indicating the prob- 
 able results to be secured from different substances, but as it is not 
 possible to intensify all the conditions in the same degree, some 
 must be vitally changed in their relation to the others and hence 
 too much reliance must not be placed upon the net results with- 
 out first making a careful comparison with those secured under 
 the actual conditions of service which it is sought to determine. 
 An accelerated test sometimes employed in this country was 
 devised by the Committee on Corrosion of the American Society 
 for Testing Materials. A piece of the metal to be tested ma- 
 chined to 2" X Y^" X He" is suspended by a small hole near 
 one end on a glass rod or other inactive and non-conducting sub- 
 stance for 2 hours in an aqueous solution of 20% (by weight) 
 of sulphuric acid at ordinary temperatures. The percentage of 
 loss in weight is used as the index. 
 
 In general, the addition of small amounts of an inorganic salt 
 
io8 CORROSION 
 
 in water increases the corrosive action of the solution until a' 
 maximum effect is reached, termed the critical concentration. 
 Further addition decreases the. "corrosive action of the solution 
 and at the saturation point (limiting concentration) corrosion is 
 inhibited. Certain experiments have shown that concentrated 
 solutions of most salts are less corrosive than pure water, some pf 
 the exceptions, within different temperature ranges, being 
 ammonium chloride, sodium sulphate, potassium nitrate, and 
 barium chloride. The corrodibility usually increases with in- 
 crease of temperature. Changes in action may take place at a 
 definite temperature (inversion temperature) : Thus above 14 C. 
 (57 F.) solutions of sodium chloride have greater corrosive effect 
 on iron than distilled water; below this temperature the reverse 
 is the case "(Friend). 
 
 According to the electrolytic theory, when iron (or a given 
 substance) is in contact with a more electro-positive substance, 
 or, due to heterogeneousness of composition, when certain particles 
 or constituents are more electro-negative than others, in the pres- 
 ence of moisture Or of water containing dissolved substances and 
 acting as an electrolyte, a current is set up which causes oxidation 
 or solution of the iron or of the more electro-negative constituent. 
 According to Longmuir it "depends upon the solubility of iron in 
 
 Eure water, or, expressed in another form, upon the pressure of 
 ree hydrogen ions in the purest water." This action may also 
 be increased or diminished by the flow of a current of electric- 
 ity generated outside of the couple, depending upon its direction. 
 The Bureau of Standards has used the terms electrolytic corro- 
 sion when the damage is caused by stray electric currents, 
 and self -corrosion for the natural corrosion (also termed autoelec- 
 trolysis or autogenous electrolysis) when structures in the 
 ground decay unaccelerated by an external e.m.f . In this theory 
 it is stated that it takes place at ordinary temperatures only in 
 the presence of water through the reaction Fe -f- 2 H' >Fe" + 2 H. 
 This means that a metallic iron atom, electrically neutral, inter- 
 acts with two hydrogen ions present in water and which carry elec- 
 trical charges; the result is the production of an iron atom which 
 takes up the two electric charges from the hydrogen ions, and the 
 deposition of two atoms of hydrogen. "All have agreed up to 
 the present in regarding carbides as being electro-negative (that 
 is, having positive electro -affinity or a greater tendency to exist 
 in the molecular than in the ionic form). Hence this action 
 should be cathodic, and they should not be attacked by corrosive 
 liquids. That this is so may be seen by microscopical exami- 
 nation" (Aitchison). Coefficient of corrosion is sometimes used in 
 connection with the corrosion of an anode, and is the ratio of 
 actual corrosion observed to that which would have occurred if all 
 of the electrode reactions determined by Faraday's law had been 
 concerned solely in corroding the anode; this has also been 
 termed efficiency of corrosion. The experiments of J. N. Friend 
 and of Heyn have shown that, although absence of electrolytic 
 cells in a very pure steel does retard the commencement of corro- 
 
CORROSION CORRUGATED SHEET 109 
 
 sion, it does not affect the rate of corrosion once the process has 
 begun (Rosenhain). 
 
 Certain substances produce marked reactions at high tempera- 
 tures at which they may even be melted. An example is the 
 method of etching with calcium chloride introduced by Saniter 
 (See Metallog., page 287). Iron is slightly soluble in molten zinc. 
 In the case of galvanizing pans it appears advantageous to keep 
 the silicon and phosphorus low, while the content of manganese 
 or carbon does not seem to have much effect. The temperature 
 of the bath is of much greater importance, the effect increasing 
 gradually up to about 490 C. (915 F.), and above this very 
 rapidly being about 30 times greater at 530 C. (985 F.) than 
 below 490 C. 
 
 The relative corrodibility of cast iron and steel depends on 
 given conditions. Thus, in ordinary air cast iron is usually more 
 resistant, also when completely submerged in water; but in 
 sulphuric acid the reverse is true. 
 
 Certain conclusions drawn by Aitchison (/. I. & S., 1916-1- 
 90-91) are as follows: 
 
 (1) That corrosion of steel takes place purely by the action of 
 ferrite on the solid solution. 
 
 (2) The action upon pure ferrite may be due entirely to the 
 potential difference set up in consequence of the different solu- 
 tion pressures of the grains of metal, and the inter-granular ce- 
 ment, it being probable that the latter is possessed of greater e.m.f. 
 
 (3) The percentage of a third element added to iron and carbon 
 must be sufficiently great to produce a fairly high percentage in 
 the solid solution, if there is to be any beneficial effect. 
 
 (4) The electromotive force of the solid solution with respect 
 to the corrosive liquid is the deciding factor. 
 
 (5) Pearlite as a whole does not corrode as a whole, but as a 
 mixture of ferrite and cementite, the disappearance of the latter 
 being due to mechanical, and not to chemical, action. 
 
 (6) Carbides are not decomposed by ordinary corrosive agents, 
 and act merely as the cathode to the anode of ferrite or solid 
 solution. Stead says (ibid., p. 99): "On long etching polished 
 sections of any aggregate of iron crystals in dilute nitric acid, 
 cupric ammonium chloride, etc., the crystals with cube faces 
 parallel to the surface are always the slowest to be attacked and 
 stand out in bold relief above the surfaces of the other crystals 
 of different orientation. Further sections of the same crystal of 
 iron cut parallel to and at an angle to the cube face if immersed 
 in acid and connected by wires to a galvanometer give an electric 
 current, proving that the cube face is electro-negative to the 
 other face. The assumption of Aitchison that the solution 
 pressure of iron crystals varies with the orientation is therefore 
 fully justified, and it is proved that strains produced by forcing 
 a needle into a cube face are not the cause leading to the develop- 
 ment of square etching pits." 
 
 Corrosion Factor. See page 107. 
 Corrosion Test. See page 107. 
 Corrugated Sheet. See page 433. 
 
1 1 o CORSIC AN PROCESS CRITH 
 
 Corsican Process. See page 140. 
 
 Cort Mill. See page 409. 
 
 Cort Process. See page 374. 
 
 Coruscation. The emission of sparks or flashes. 
 
 Cotton Tie Mill. See page 415. 
 
 Counter-current Principle. See page 204. 
 
 Country Heat. See page 71. 
 
 Couple. See page 208. 
 
 Coupling Box. See page 407. 
 
 Coupon. (i) In shearing plates, a piece of suitable size and shape 
 for physical tests not quite detached from the piece it is to repre- 
 sent; (2) in forgings, an extension left to be cut off and turned 
 down for testing. 
 
 Course. Of bricks, a layer or row. 
 
 Cover. (i) The lid of a crucible; (2) in the puddling process, man- 
 ganese is said to cover the carbon in the bath when the former is 
 high enough to prevent the latter from being oxidized for some 
 time. 
 
 Cowper-Coles Process. (i) For electrolytic iron: see page 166; 
 (2) sherardizing: see page 371. 
 
 Cowper (E. A.) Process. See page 380. 
 
 Crab. See page 407. 
 
 Crack. A fissure which has opened up to 'a certain extent due to 
 strains or brittle material. Those produced by rolling and forg- 
 ing are known respectively as rolling cracks and forging cracks. 
 Where cracks are formed on the outside, due to the rapid heating 
 of cold material, they are called heating cracks or expansion cracks. 
 Cooling cracks or contraction cracks are due to the outside not 
 being able to contract uniformly during cooling; in castings this 
 is termed checking. Thermal cracks, hot cracks or heat cracks 
 are those produced by repeated, alternate, sudden heating and 
 cooling of the surface as in the case of the rolls for rolling hot 
 steel which are subjected to the hot metal followed immediately 
 by cooling from the water spray; this also occurs at times with 
 railroad wheels and brake shoes, due to their mutual action 
 often referred to as wheel burns and brake burns respectively. 
 An internal crack or fissure is one which has formed in the inte- 
 rior, but does not (usually) extend through to the outside; this is 
 due to excessive longitudinal strains, either from cold working or 
 from too rapid cooling from the outside. In shearing hot billets, 
 etc., particularly those high in carbon, fine cracks may be formed 
 at the ends where the water drops on them; they are called water 
 cracks. 
 
 Cradle. See page 431. 
 
 Crafts Furnace. See page 155. 
 
 Cremer Process. See page 30. 
 
 Cramp Bar. See page 415. 
 
 Creeping. (i) In rolling: see page 408; (2) in testing; see page 4 72. 
 
 Cricoid. See page 290. 
 
 Crimped Sheet. A sheet, one corner or a portion of which has 
 been doubled or bent upon itself during rolling. 
 
 Crith. See Hydrogen.j 
 
CRITICAL CONCENTRATION CRUCIBLE < 1 1 1 
 
 Critical Concentration. See page 108. 
 
 Critical Cooling Velocity. See page 447. 
 
 Critical Deformation. And grain growth: see page 216. 
 
 Critical Interval. See page 265. 
 
 Critical Mechanical Tempera ture. See page 331. 
 
 Critical Points. (i) General: see page 264; (2) determination of: 
 see page 265. 
 
 Critical Range. Of temperature: see page 265. 
 
 Critical Strain. See page 216. 
 
 Critical Temperature. See page 264. 
 
 Crocodile. See page 489. 
 
 Crocodile Hammer. See page 196. 
 
 Crocodile Shears. See Shears. 
 
 Crocodile Skin. See page 229. 
 
 Crocodile Squeezer. See page 377. 
 
 Crook. A distortion in castings produced in cooling. 
 
 Crookes' Radiometer. See page 207. 
 
 Crop ; Crop End. See Discard. 
 
 Cropping Shears. See Shears. 
 
 Cross Breaking Rupture. See page 336. 
 
 Cross Breaking Strength. Of cast iron: see page 484. 
 
 Cross Pane. See Pane. 
 
 Cross Piling. See page 378. 
 
 Cross Rolls ; Rolling. (i) of plates, etc. : see page 414; (2) of tubes : 
 see page 490. 
 
 Cross-section ; Cross-sectional Area. See page 468. 
 
 Cross Welding. See page 502. 
 
 Crossed Twinning. See page 1 24. 
 
 Crova's Pyrometer. See page 208. 
 
 Crown. Of plates: see page 414. 
 
 Crown Bar. Merchant bar of wrought iron. 
 
 Crucia Steel. See page 451. 
 
 Crucible. The hearth of a blast furnace: see page 27. 
 
 Crucible. Also called pot, is used for melting small amounts of 
 various materials, but more particularly for the manufacture 
 of crucible steel. For this industry crucibles are made of a 
 high quality of clay mixed with a little powdered coke (clay 
 crucible or white pot), or of a mixture of clay and graphite 
 (graphite, plumbago, or blacklead crucible). 
 
 Graphite crucibles can be made to contain a heavier charge, 
 and also a greater number of heats. They are made of a mix- 
 ture of Ceylon graphite, German clay and pure sand, the final 
 composition being approximately: 
 
 Carbon 50% 
 
 Silica 35 
 
 Alumina 1 1 
 
 Iron oxide, etc 4 
 
 The clay is dried, ground, made into a paste with water, and 
 the sand and graphite thoroughly mixed in, after which the 
 mass is allowed to remain for a few days in a damp place to 
 
112 CRUCIBLE 
 
 season or temper, i.e., be in a better condition for working. 
 The amount of crucible material prepared at one time is called 
 a batch. A lump of the proper size is cut off, kneaded slightly 
 to insure its uniformity, and put inside a mold which is placed 
 on a potter's wheel, and the mass spun up (by revolving the 
 wheel) to fill the mold. The proper thickness of the wall is 
 obtained by means of an arm or profile iron which descends 
 and shapes the inside of the crucible. The excess at the top 
 of the mold is sliced off and the mold removed. Spinning up 
 gives better results than simple pressing because it causes the 
 flakes or plates (in which natural graphite occurs) to take a 
 tangential direction and intermesh, thereby binding the material 
 together. Artificial graphite is rarely if ever used as it does not 
 occur in these plates. 
 
 The crucibles are now dried, first for about 24 hours, at about 
 20 to 25 C. (70 to 80 F.), after which they are smoothed 
 up; and then for about three weeks at a temperature high enough 
 to drive off the hygroscopic moisture. They are then heated 
 (annealed or burned) in an oven (annealing oven) for about three 
 days at a temperature of about 815 C. (1500 F.) to drive off 
 all the combined water. The crucibles are stacked up in a 
 number of tiers, and, as they are still very; tender, they are placed 
 in loose-fitting clay molds (seggars or saggars) which keep them 
 from being crushed, and also prevent excessive oxidation. When 
 crucibles of different sizes are being made they are usually nested, 
 i.e., the smaller are placed inside the larger. The slight oxida- 
 tion of carbon on the surface, which always occurs, gives the 
 crucibles, originally black, a brownish color (the color of the 
 clay). The covers are made and treated in a similar manner. 
 
 Clay crucibles, used chiefly in England, are manufactured 
 from a high grade of fireclay (Burton, Stourbridge, etc.), usually 
 mixed with about 5 % of good ground coke. The mixing is 
 done very carefully, frequently by treading the mass with the 
 bare feet on the treading floor. A lump is then placed in a 
 flask or mold, and a plunger having the shape of the interior 
 is forced down, being centered by a pin passing through a hole 
 in the bottom. The flask is removed and the top of the crucible 
 forced inward, by means of another conical mold, to give it 
 a shape like a barrel. After drying for a few days in the pot 
 house (where they are made), the crucibles are further dried 
 at a somewhat higher temperature near the flues of the melting 
 furnaces. The hole left in the bottom is closed when the crucible 
 is set in the furnace for use by throwing in a little sand which 
 frits the crucible to the clay stand on which it rests. 
 
 Crucibles are generally supposed to improve with age, and 
 for this reason they are frequently kept for some time to season. 
 If they have not been dried thoroughly before use, the moisture 
 is likely to cause portions to crack off, called scalping, when they 
 are heated. In some cases fine cracks (alligator cracks, because 
 they give the outside the appearance of alligator skin) may de- 
 velop after a crucible has been in service some time; they are prob- 
 ably due to hot gases and improper annealing. Another defect of 
 
CRUCIBLE CAST STEEL CRUCIBLE PROCESS 113 
 
 infrequent occurrence is where small fissures (pin holes) are formed, 
 allowing drops of metal to run out. Generally they do not appear 
 until the crucible has been used for a few heats, and are originated 
 in the drying or the annealing. A crucible is said to run when it 
 cracks and the contents leak out. 
 
 Crucible Cast Steel. Crucible Steel. 
 
 Crucible Furnace. See pages 114 and 183. 
 
 Crucible Fusion. See below. 
 
 Crucible Process. Also called pot melting a process for the pro- 
 duction of steel, consisting in melting down in closed crucibles 
 various grades of iron or steel with or without the addition of 
 carbon, ore, or other materials, the resultant product being cast in' 
 a fluid condition. As ordinarily practised, it is essentially a 
 melting operation, there being little if any purification, except 
 perhaps as regards oxides or gases. The process was invented 
 by Robert Huntsman about 1 740. The most important modifi- 
 cations are (Howe) : 
 
 1. Huntsman's, the original method (sometimes called crucible 
 fusion), in which small pieces of blister or other highly carburized 
 steel are melted alone or with a slag-making flux (e.g., glass). 
 
 2. Josiah Marshall Heath's modification of adding manganese, 
 either previously reduced by heating its oxide with carbonaceous 
 matter or reduced in the process itself by the action of charcoal 
 on oxide of manganese. Huntsman's method thus modified, it 
 is said, is now the prevalent one in Sheffield. 
 
 3. The carburizing fusion (or cementing fusion) method, 
 in which the percentage of carbon in the product is regulated 
 by the addition of carbonaceous matter (practically charcoal), 
 is said to have been used in the last century by Chalut and Clouet, 
 and is the prevalent method in this country. 
 
 4. Uchatius, or the pig and ore method, of melting granu- 
 lated cast iron with iron ore. 
 
 5. The pig and scrap method of melting wrought iron or steel, 
 or both, raising the proportion of carbon by adding cast iron. 
 
 In all the above methods the molten metal is tranquilized 
 by killing, i.e., holding it molten so as to yield sound ingots. 
 
 6. The Mitis method, in which the charge originally con- 
 stituted in any of the above ways, is tranquilized by the adition 
 of ferro-aluminum (or aluminum) immediately after fusion, and 
 is teemed a few minutes later. 
 
 7. The basic method, or fusion in basic instead of silicious 
 crucibles, to permit of the elimination of phosphorus and sul- 
 phur, does not appear to have had any practical application. 
 
 In Bajault and Roche's process powdered ore and pig iron 
 were N put in cast-iron molds and heated in a furnace. The pig 
 iron and the mold reacted with the ore, the whole forming one 
 ingot which was to be broken up and used in the crucible process. 
 The materials would have to be pure, and the advantage to be 
 gained from conducting the pig and ore process in two separate 
 operations is not evident. Kern's process appears to be a 
 modification of the carburizing fusion method, being conducted 
 in two stages: (a) soft open hearth steel was melted with charcoal 
 '8 
 
114 CRUCIBLE PROCESS 
 
 in graphite crucibles, (6) the highly carburized product thus 
 obtained was then used in place of cement steel, mixed with 
 wrought iron, etc. 
 
 Graphite crucibles (see Crucible) are used in this country 
 and principally on the Continent; clay crucibles chiefly in 
 England; in this latter case the process is sometimes referred to 
 as the white crucible process. The crucible furnace may be 
 heated by gas, coal, or coke. If the former, it is regenerative in 
 principle, and consists of a number of chambers or holes (melting 
 holes) about 6 to 15 holes to each furnace, each hole holding 
 6 crucibles in which the combustion of the gas takes place. 
 The bottoms of the holes are covered with coke dust to protect 
 the brick-work in case a crucible is broken, and provided with 
 a hole to permit of cleaning. The covers for the holes are some- 
 times called clamps or bungs. In coal or coke furnaces (pot hole, 
 coke hole, fire hole rarely called shaft furnaces) the crucible 
 is set directly in the fuel, which is supported by grate bars, a 
 chamber being provided underneath for cleaning, called the 
 cave. Poking the fuel around the crucible is sometimes called 
 pottering down (Eng.). Principally on the Continent and in a 
 few cases in this country what is termed a Krupp Furnace is em- 
 ployed; this resembles a small open hearth furnace and the pots 
 are charged and drawn horizontally through the doors. In 
 contradistinction to this the other type of furnace, in which the 
 pots are charged and drawn vertically, is referred to as a hole 
 furnace. In this country the charge is ordinarily 100 pounds, 
 and the graphite crucible weighs about 50 pounds when new. 
 The material employed is usually wrought iron or soft-steel scrap, 
 together with a certain proportion of charcoal and oxide of man- 
 ganese; occasionally blister steel is used, in which case the char- 
 coal is omitted. The larger pieces are put at the bottom by the 
 pot packer, the charcoal and oxide of manganese on these, and 
 the smaller pieces at the top; the cover is put on and the crucible 
 set in the furnace by a man called the setter in. The charge is 
 occasionally introduced into the crucible (while in the furnace) 
 by means of a runnel or charger. Depending on the composition 
 of the charge (low carbon heats take much longer than high 
 carbon) the melting, which is the first stage of the process, takes 
 about 2 to 4 hours, and when it is judged that this has taken 
 place, the man in charge, or melter, looks over the heat, i.e., 
 uncovers certain of the pots to determine with his eye the condi- 
 tion of the contents; if necessary, he stirs them with a small 
 rod to detect unmelted pieces. When this period is completed, 
 the charge is allowed to remain a further period until the steel 
 becomes tranquil, i.e., does not evolve gas. This result is prob- 
 ably effected by silicon, reduced by carbon acting on the wall 
 of the crucible, combining with the gases. This tranquilizing 
 period is known as killing, and the steel when perfectly quiet is 
 said to be dead. The bubbles of gas which form and break 
 slowly toward the end of the killing period are sometimes called 
 cat's eyes ; they are larger than when the charge is first melted. 
 Killing takes from about % to i % hours usually from % to i 
 
CRUCIBLE PROCESS 115 
 
 hour -and if unduly prolonged the metal when cast is hard 
 and brittle (also called dead), probably on account of excessive 
 absorption of silicon. The total time required for a heat is 
 about 3 to 4 hours, three heats being made each turn of 12 
 hours. When ready the crucibles are drawn from the melting 
 hole by the puller out, set on the floor and the covers removed. 
 In some cases they may be set temporarily in an iron-lined 
 hole (teeming hole) in the floor. The slag (scum or flux) float- 
 ing on top of the steel is removed (swabbed up) by means of a 
 light iron rod with a ball of slag on one end (mop) against which 
 it chills. Drawing by some mechanical device, instead of by 
 hand, has not proved satisfactory as the crucibles are liable to 
 slip or else be crushed. The steel is now teemed (poured) into 
 molds, and any slag remaining is kept back by holding a bar 
 (flux stick) against it. Each mold receives the contents of one 
 crucible, or, if of larger size, several cruciblefuls are used, care 
 being taken in every case that the stream does not strike the sides, 
 and also that it is not momentarily interrupted, the latter causing 
 the metal to freeze over (cold shut). Several cruciblefuls may 
 also be poured into a ladle and the molds filled from this. The 
 ingot after cooling is topped (the top broken off) to determine the 
 grade by the appearance of the fracture (chemical analysis is now 
 largely employed for this), and also for the purpose of removing 
 the piped portion. Graphite crucibles were formerly allowed 
 to cool between heats, but now are usually charged hot, i.e., 
 returned to the furnace immediately without cooling after being 
 inspected for cracks. After about nine heats they are allowed to 
 cool completely for more careful inspection, their average life 
 being six to nine heats. In English practice, where clay crucibles 
 are used, the life of a crucible is about three heats, and the charges 
 are reduced successively on account of the slag line or flux line 
 which is left after each operation. The first charge is about 56 
 pounds, the succeeding ones being about 44 and 38 pounds respec- 
 tively. Owing to the fact that the crucible is cold for the first 
 heat, this takes about 4^ to 6 hours, the subsequent heat taking 
 less, as then the crucible is returned to the furnace immediately; 
 three heats are obtained in 12 hours. When solid fuel is used, 
 care must be taken that none falls into the crucible, as the steel 
 is thereby rendered red short, and its fracture, which is brilliant, 
 is said to stare. The store room in which the raw materials for 
 the charge, particularly the ingredients for special steels, is 
 sometimes called the medicine room. 
 
 "In hammering crucible ingots for tool steel it used to be 
 customary to heat them first to a comparatively low temperature, 
 not high enough to produce scale, and then cog (forge) them under 
 a steam hammer by very light blows, not sufficient to reduce 
 materially the dimensions of the ingot but merely to smooth 
 and slightly " compact' ' its surface. The ingot was then replaced 
 in the heating furnace, brought to as high a temperature as its 
 composition would permit, being rolled from time to time in a 
 welding mixture, and then quickly returned to the hammer where 
 it was roughly brought to the required cogged bar size. The 
 
1 1 6 CRUCIBLE PROCESS 
 
 first operation was known as saddening, and the low, non-scaling 
 temperature was spoken of as a saddening heat. The idea was to 
 smooth the rough surface of the ingot as such a surface was less 
 likely to be burned at the subsequent temperature. It was also 
 believed that blowholes lying close to the surface would thus be 
 closed before a scaling heat had a chance to open and expose 
 them to oxidation" (G. Aertsen). "In crucible steel works 
 practice it is sometimes the custom to heat the steel to, and forge 
 from, what is called the wash-welding temperature (sufficiently 
 high to cause the scale to run and also to promote welding), and 
 it is assumed that if the material initially contains cavities or 
 blowholes, they will be welded up" (Stead). 
 
 General Principles. The charge contains initially a moderate 
 quantity of oxygen as rust, scale, and the slag of wrought iron. 
 This, as well as the trifling quantity of atmospheric oxygen orig- 
 inally present, and free oxygen and the oxygen of any carbon 
 dioxide of aqueous vapor which may enter by leakage or by 
 diffusion, should tend to form oxide of iron and (if the charge 
 contains spiegeleisen or ferro-manganese) of manganese. This 
 tendency is opposed by the carbon of the crucible walls, which, 
 especially in the case of new graphite crucibles, tends to take up 
 the free oxygen and to reduce the carbon dioxide present. 
 
 The metallic oxides, melting first to a very basic slag, should 
 collect at the bottom of the crucible and react on its walls, 
 and later, on the bath of molten steel. The first action of the 
 slag on the metal should be strongly fining, tending to oxidize 
 carbon, silicon, and manganese. As the slag level is gradually 
 raised by the accumulation of the molten steel beneath, the slag 
 corrodes ring after ring of the crucible wall, exposing the graphite 
 or coke to the rising underlying metal, which absorbs carbon 
 voraciously. The fining action should thus weaken rapidly as 
 the slag grows acid through absorption of silica from the crucible, 
 and through the reduction of its oxides, partly by the metal's 
 carbon and silicon, partly (in the case of strongly graphitic 
 crucibles chiefly) by the carbon of the crucible. This fining 
 probably soon gives way to carburization, the carburized me'tal 
 reducing and absorbing silicon from the now acid slag and from 
 the acid crucible wall. The net result, under usual conditions, 
 is that in graphite crucibles the metal gains in carbon (usually 
 by from o to 0.25%) and in silicon (usually by from 0.05 to 
 0.20%); that if spiegel or ferro-manganese is charged before 
 melting, much of its manganese is slagged, and the absorption 
 of carbon and silicon is increased; and that if oxide of manganese 
 is charged, part of its manganese is sometimes, if not usually, re- 
 duced and absorbed by the metal. The more highly carbureted 
 the crucible wall, the greater will be the net absorption of car- 
 bon, manganese, and silicon. 
 
 In clay crucibles, the charge either loses carbon (say up to 
 0.25%) or gains but slightly (say up to 0.06%), while gaining 
 but slightly in silicon, unless manganese or its oxide be present. 
 
 If the charge contains charcoal or graphite, this both carburizes 
 the metal during heating to the melting point (probably most 
 
CRUCIBLE PROCESS 1 1 7 
 
 of its carbon is absorbed by the steel), and greatly shortens and 
 weakens, if it does not eliminate, the fining period by protecting 
 iron and manganese from oxidation, and by reducing at least a 
 part of their oxides. 
 
 If, on the other hand, oxide of manganese is charged, it tends 
 to intensify and prolong the fining, to postpone and enfeeble 
 the carburization, opposing the action of the charcoal. 
 
 The silicon absorbed during the killing period probably 
 tranquilizes the steel, principally by removing any oxides or free 
 oxygen present, although in addition it is supposed to give the 
 steel the property of retaining gases which it contains, such as 
 nitrogen. 
 
 Sulphur increases gradually but constantly, being taken up 
 perhaps from the pyrites of the clay or graphite, perhaps from 
 that of the fuel, very small quantities of sulphur dioxide entering 
 the crucible. 
 
 Phosphorus, in like manner, increases slightly when clay or 
 graphite crucibles are used, but is eliminated gradually in basic 
 crucibles. 
 
 Comparative Quality of Crucible Steel. As already stated, 
 in the United States it is generally customary to use wrought 
 iron (sometimes basic open hearth steel) in contact with charcoal 
 in the crucible itself. In Europe blister steel is usually em- 
 ployed. This latter method necessitates a separate, very lengthy 
 treatment previous to the melting down in crucibles. It is 
 claimed (and also disputed) that as good steel is produced by the 
 American method as by the English. Crucible steel is better 
 than open hearth or Bessemer steel for the following reasons: 
 
 (a) The materials used are more carefully selected. 
 
 (6) Smaller units are handled which receive greater attention. 
 
 (c) It is not exposed to the atmosphere. 
 The relative qualities are : 
 
 1. Crucible, 
 
 2. Open hearth, 
 
 3. Bessemer, 
 
 and taken in the same order, the crucible steel has least contact 
 with the atmosphere, and the Bessemer most. 
 
 It is claimed that it is possible to produce in the electric furnace 
 steel of crucible quality or even better. The electric furnace 
 with a basic hearth permits of refining not possible in the acid 
 crucible. It also operates without furnace gases in contact with 
 the charge and can be made to exclude nearly all circulation of 
 air. Electric steel is made in larger units and for this reason 
 cannot receive the same meticulous care; for the same reason 
 its uniformity should be greater especially for large ingots. 
 However, the most expensive tool steel is still manufactured in 
 crucibles. 
 
 A number of early processes or modifications did not possess 
 any particular novelty or value, as will be seen from the follow- 
 ing: Charles Atwood's process consisted essentially in melting 
 together wrought iron and cast iron (spiegel preferred). George 
 
1 1 8 CRUCIBLE STEEL CRYPTODIMORPHISM 
 
 Brown's process consisted in melting wrought iron, cut up into 
 small pieces, with charcoal pig iron, in the proportion of about 
 three parts of the former to one of the latter. Victor Gallet 
 coated puddle bar with a paste consisting of certain proportions 
 of limestone, vegetable mold or clay, carbonate of potash, oxide 
 of manganese, resin, soot, wood charcoal, etc., and melting in a 
 crucible. Charles Low devised a truly remarkable process in 
 which wrought iron was to be melted in crucibles with a mixture 
 of manganese dioxide, plumbago, charcoal, and niter. A. V. 
 Newton's process consisted in heating crucibles and their charge 
 of blister bars in an auxiliary furnace before putting them in the 
 regular melting furnace, by which means he claimed a consider- 
 able reduction in the time required. William Onions' process 
 consisted in melting in a crucible two parts of hematite ore, four 
 parts of steel, and 94 parts of pig iron, the resulting metal being 
 poured directly into molds, and the castings subsequently an- 
 nealed. D. S. Price and E. C. Nicholson's process consisted sim- 
 ply in melting refined pig with suitable proportions of wrought 
 iron. Obersteiner fused pig with wrought iron. Sudre's 
 process consisted in melting steel (blister steel) in a reverberatory 
 furnace, instead of in a crucible, and the employment of bottle 
 glass for flux. In J. L. Talbot and J. D. M. Stirling's process 
 various proportions of oxides were added to blister bars during 
 melting in crucibles to get steel with different percentages of 
 carbon. John Thompson proposed to produce refined cast steel 
 by melting it in a furnace (instead of in crucibles) of peculiar 
 construction, resembling a puddling furnace, in which were 
 placed troughs or other vessels containing the metal. Win. 
 Vickers' process consisted in melting wrought-iron scrap with 
 ground charcoal and oxide of manganese; cast-iron scrap might 
 also be used. 
 
 Crucible Steel. Steel made by the crucible process; also called 
 cast steel, Huntsman steel (obs.), pot steel (Eng.). 
 
 Crude Iron (obs.). Untreated pig iron. 
 
 Crude Steel. See page 343. 
 
 Crumble. Of the cutting edge of a tool which breaks away in 
 small particles because it is too hard or has not the proper shape. 
 
 Crushed Coke. See page 97. 
 
 Crushed Steel. An abrasive material usually made by quenching 
 high-carbon steel from a high temperature and crushing, followed 
 by tempering to a straw color. 
 
 Crushing. Breaking up into a smaller size, for such material as 
 ore, limestone, etc. 
 
 Crushing Strength. Compressive strength : see page 330. 
 
 Crux. An abbreviation sometimes used for crucible. 
 
 Cryocarbide. See page 273. 
 
 Cryohydrate. See page 266. 
 
 Cryosel. See page 266. 
 
 Cryptocellular Structure. See page 126. 
 
 Cryptoclastic Structure. See page 126. 
 
 Cryptocrystalline. See page 126. 
 
 Cryptodimorphism. See page 122. 
 
CRYSTALS CRYSTALLOGRAPHY 1 1 9 
 
 Crystals. (i) General: see below; (2) laws of: see page 120; (3) 
 properties of: see page 121; (4) structure of: see below. 
 
 Crystal-boundary Etching. See page 127. 
 
 Crystal Centers. See page 1 20. 
 
 Crystal Cleavage. See page 123. 
 
 Crystal Debris. See page 125. 
 
 Crystal-field Etching; Crystal-figure Etching. See page 127. 
 
 Crystal Grain. See page 122. 
 
 Crystal Growth. See page 121. 
 
 Crystal Plane. See page 123. 
 
 Crystal Size. See page 121. 
 
 Crystal Skeleton. See page 122. 
 
 Crystal Thrust See page 121. 
 
 Crystal Unit Slipping. See page 281. 
 
 Crystalliform. See below. 
 
 Crystalline. See below. 
 
 Crystalline Aggregate. See page 125. 
 
 Crystalline Antimony. See Antimony. 
 
 Crystalline Boron. See Boron. 
 
 Crystalline Carbon. See Carbon. 
 
 Crystalline Deformation. See page 126. 
 
 Crystalline Force. See page 121. 
 
 Crystalline Fracture. See page 178. 
 
 Crystalline Grain. See page 122. 
 
 Crystalline Growth. See page 213. 
 
 Crystalline Magnesite. See page 397. 
 
 Crystalline Movement. See page 281. 
 
 Crystalline Slip. See page 282. 
 
 Crystalline Solid Solutions. See page 270. 
 
 Crystalline State. See below. 
 
 Crystalline Structure. See below. 
 
 Crystalline Tin. See Tin. 
 
 Crystallite. See page 122. 
 
 Crystallization. (i) General: see below; (2) systems of: see page 
 120; (3) water of: see page 499. 
 
 Crystallization by Annealing. See page 213. 
 
 Crystallographic Amorphizing. See page 282.' 
 
 Crystallographic Axis. See below. 
 
 Crystallographic Plane. See below and page 123. 
 
 Crystallography. The study of crystals which are solid bodies 
 bounded by plane surfaces or faces at definite angles to each other, 
 and formed by the arrangement of the molecules, which arrange- 
 ment is symmetrical to certain imaginary lines or axes (crystallo- 
 graphic axes) intersecting at the center, or to certain planes 
 (Crystallographic planes or planes of symmetry) intersecting 
 the Crystallographic axes. The relative inclination of the axes 
 to a certain plane or line is called the orientation of the crystal. 
 This regular structure (and a body possessing it) is termed crys- 
 talline or crystalliform (crystalline state) ; a body in which these 
 properties are absent, amorphous or non-crystalline. The 
 measurement of the angles of a crystal is performed by the aid of 
 an instrument called a goniometer. 
 
1 20 CRYSTALLOGRAPHY 
 
 Systems of Crystallization. Crystals may be classified accord- 
 ing to their form or crystallization, into six different systems 
 which are (Moses and Parsons, "Mineralogy, Crystallography, 
 etc.," 6): 
 
 i. Isometric (cubic, monometric, regular, tesseral, or tessular) 
 system : Three interchangeable axes at right angles to each 
 other. 
 
 1 2. Tetragonal (dimetric, monodimetric, pyramidal, quadratic, 
 or quarternary) system: Three axes at right angles, of which 
 two are interchangeable. 
 
 3. Hexagonal (rhombohedral, rhombohedric, or monotri- 
 metric) system: Four axes, three of which lie in one plane at 60 
 degrees to each other and are interchangeable; the fourth is at 
 right angles to the other three. 
 
 4. Orthorhombic (anisometric, orthosymmetric, prismatic, 
 rhombic, or trimetric) system : Three axes at right angles but not 
 interchangeable. 
 
 5. Monoclinic (clinorhombic, hemiprismatic, monoclinohedral, 
 monosymmetric, or oblique) system: Three non-interchangeable 
 axes, two of which are oblique to each other; the third is at 
 right angles to the other two. 
 
 6. Triclinic (anprthic, asymmetric, clinorhomboidal, doubly 
 oblique, tetarto prismatic, or triclinohedral) system: Three non- 
 interchangeable axes at oblique angles to each other. 
 
 Any general reference to the optical properties of crystals 
 (polarization, etc.) is omitted as metallic crystals are opaque 
 except in extremely thin sections which have no practical 
 importance. 
 
 Moses and Parsons (loc. cit., 2 et seq.) give the following three 
 fundamental laws of crystals : 
 
 1. Law of constancy of facial angles: In all crystals of the 
 same substance the angles between corresponding faces are 
 constant. 
 
 2. Law of symmetry: All crystals of any one substance are of 
 the same grade of symmetry. 
 
 3. Law of simple mathematical ratio: In all crystals of the 
 same chemical substance, if the intercepts of any face upon the 
 crystallographic axes are divided, term by term, by the corre- 
 sponding intercepts of any other face, the quotients will always be 
 simple rational numbers or infinity or zero. 
 
 Formation of Crystals. According to the researches of Bragg, 
 in which he employed a Rontgen ray spectrometer to study the 
 constitution of crystals, they are made up of atoms and not of 
 molecules. There are different theories or hypotheses as to their 
 origin and growth. According to one, they start from a globular 
 or utricular mass (globulite). These are sometimes referred to as 
 embryonic crystals. In heterogeneous crystal mixtures, ab- 
 sorbens is the name which has been given to one crystal form 
 when it expands with decreasing temperature and absorbs the 
 other form (Guertler). The points of origin in building up 
 crystals which may be invisibly small and grow by accretion or 
 coalescence (merging) are called by Tammann crystal centers. 
 
CRYSTALLOGRAPHY 121 
 
 The space-lattice theory of crystallization is that the atoms 
 (or molecules) are not in actual contact but separated in accord- 
 ance with a well denned and regular pattern or structure. The 
 cubical space (this refers to volume and not to form) included 
 within intersecting planes passing through a set of neighboring 
 atoms is called the space-lattice. Quincke's hypothesis holds 
 that crystallization commences when in the liquid state, the 
 liquid first separating into two immiscible phases, one of which is in 
 relatively large quantity and is composed of the pure substance, 
 the other or smaller containing any impurities or eutectic. This 
 acts somewhat like an emulsion of oil and water, the smaller or 
 oily liquid forming the walls (foam walls or cell walls) of foam 
 cells filled with the pure substance, each spheroid of which being 
 isolated can develop its own orientation, either while still liquid 
 or after complete solidification. Such a structure is known as a 
 foam. Depending upon their mode of formation and structure 
 they have been divided into first, second, and third order, or 
 first-class and second-class cells ; also primary, secondary and 
 tertiary crystals. Osmond and Werth referred to simple cells, 
 bounded by ferrite, and compound cells which were larger and 
 composed of dendritic crystals. The formation of grains im- 
 mediately upon solidification Belaiew calls granulation, and where 
 it occurs, the granulation range or zone ; and this action, primary 
 crystallization ; the secondary effect when pearlite is formed at 
 Ari, secondary crystallization. Arnold suggests centrifugal 
 extrusion to express the action when metal crystallizes and any 
 substances are thrown to the edge. According to Desch it is 
 not necessary to assume that crystallization is due to the exist- 
 ence of a separate crystalline force, as the ordinary cohesive 
 forces in solids have, in crystals, vector properties and act more 
 strongly in certain directions than in others; this is implied in 
 the idea of a crystal, and the phenomenon of crystal thrust is to 
 be explained as the result of the vectorial character of cohesion. 
 The size of crystals, i.e., their growth, under normal conditions 
 depends upon the rate of solidification or cooling while they are 
 still at high temperatures where conditions permit of sufficient 
 mobility for the rearrangement of the particles so certain crystals 
 grow at the expense of the others. Howe refers to parallel 
 growth where crystals extending in the same direction are con- 
 nected or grow together. 
 
 Properties and Structure of Crystals. Morphology (particu- 
 larly in biology) is the science of form and structure; morphometry 
 is the method of measuring external forms. Isomorphism or 
 homoeomorphism is where different substances crystallize in 
 identical or closely related forms. Mitscherlich's law states 
 that elements in compounds may be replaced by other similar 
 elements without changing the crystalline form (e.g., manganese 
 partly replacing iron in cementite). Monomorphic refers to a 
 crystal of the same or similar form. Polymorphism or multiple 
 isomorphism is the property of crystallizing in more than one 
 form; where there are two forms, the term dimorphism is some- 
 times used, and for three forms, trimorphism; isodimorphism is 
 
122 CRYSTALLOGRAPHY 
 
 where two substances, in addition to independent forms, can 
 crystallize in another common form; if the presence of both 
 is necessary it is a case of cryptodimorphism or cryptomorphism. 
 Metamorphism is the change or reformation (recrystallization) 
 due to some agent such as heat (thermal metamorphism or 
 pyrometamorphism) ; a rock, for example, which owes its 
 (crystalline) form to heat is said to be pyromorphous ; pyrocrys- 
 taltine refers to a body crystallized from the molten state. 
 Static metamorphism is a change brought about by gradual or 
 steady forces; dynamic metamorphism, by suddenly applied 
 forces; if such a change is incomplete it is a case of hemimeta- 
 morphosis. A pseudomorphic crystal or pseudomorph is one 
 which results (a) from the substitution or chemical alteration of, 
 and has the same form as, a crystal previously existing, or (b) 
 from deposition in the space which a crystal previously occupied. 
 An allomorph is a pseudomorph where there is no change in 
 chemical composition. A paramorph is a crystalline form of one 
 substance assumed by another of similar chemical composition 
 but of different properties. Heteromorphic indicates a sub- 
 stance differs in form or properties from the normal. The prefix 
 holo- is used to denote completeness, as holocrystalline, entirely 
 crystalline (containing no amorphous matter); holosymmetric, 
 entirely symmetric; holoisometric, completely crystalline ac- 
 cording to the isometric system; holoaxial, having all the axes 
 but none of the faces; holohedral or homohedral, .having the 
 complete set of crystal faces for the given form. An anhedron 
 or faceless crystal is a crystal without definite bounding planes; 
 a hemihedron is one having only half the regular number of 
 faces. A crystal is said to be orthobasic when the axes are at 
 right angles to each other. Complete crystals, i.e., those which 
 have been formed when the conditions were favorable for their 
 complete development, are called idiomorphic, automorphic or 
 euhedral crystals; a large crystal of this nature is sometimes 
 termed a metacryst. If their bounding surfaces are determined 
 by adjacent (interfering) crystals or bodies, they are called 
 incomplete, hemicrystalline or allotriomorphic crystals. In the 
 case of metals these last are termed crystalline grains, crystal 
 grains or, more usually, simply grains or granules, and a struc- 
 ture made up of them is said to be granular or granulitic. 
 
 In the primary crystallization referred to above the growth is 
 by a process of repeated branching in the directions where there 
 is the least interference. These formations are termed crystal- 
 lites, star-like crystallites, skeletal crystals, skeleton crystals, 
 crystal skeletons, and particularly because of this branching form 
 and their supposed resemblance, dendrites, or dendritic, ar- 
 borescent, tree -like, fir-tree, pine-tree and fern-leaf crystals 
 or crystallites. A microlite is a more or less completely defined 
 microscopic crystal. Cuboid is a term tentatively applied to 
 crystals which appear to be of cubical form before this has been 
 determined definitely. Crystallites which are wedge shaped are 
 sometimes said to be cuneiform or cuneate. 
 
 A unit crystal is the smallest piece of matter which can possess 
 
CRYSTALLOGRAPHY 1 23 
 
 all the properties of a crystal. The components or grains of a 
 crystallite form are sometimes referred to collectively as colonies 
 (of grains). The term spicule is used to describe something 
 which is thread-like in form with pointed ends. If before solidi- 
 fication is complete the still molten portion is removed, the crystal 
 so exposed is called an isolated crystal. In the case of solutions 
 of certain organic substances Lehmann found globules which 
 acted on polarized light in the same way as ordinary (transparent) 
 crystals and which he termed liquid crystals ; the same term is 
 also applied to cases which have been found with metallic (solid) 
 crystals which are extremely plastic, resembling fluids in this 
 respect, although in general a crystalline structure has a decid- 
 edly embrittling effect. 
 
 Crystal Planes. These may be classified as follows : 
 
 1. Planes of symmetry: A plane which "so divides the crystal 
 that either half is the mirrored reflection of the other, and every 
 line perpendicular to the plane connects corresponding parts of 
 the crystal and is bisected by the plane of symmetry" (Moses 
 and Parsons, 5); sometimes referred to as the crystallographic 
 plane. 
 
 2. Motion planes (Howe): Those where movement of the 
 particles occurs, also termed planes of weakness. 
 
 (a) Cleavage planes : Those along which a crystal breaks 
 or separates, "always parallel to faces of forms in which 
 the substance can crystallize . . . True cleavage is 
 obtained with equal ease at any part of a crystal, and 
 there is only a mechanical limit in the closeness of one 
 cleavage to the next" (Moses and Parsons, 146-7). 
 
 (6) Gliding planes: Those where "it has been observed 
 that pressure in certain directions will either produce a 
 separation along a definite plane, which is not a true 
 cleavage plane, or else will develop a twin structure 
 (secondary twinning) with this gliding plane as the twin 
 plane" (Moses and Parsons, 148). 
 
 (c) Parting planes: "The planes along which a gliding has 
 occurred may thereafter be planes of easy separation or 
 parting, differing from true cleavage, however, because 
 in parting the easy separation is limited to the planes 
 of actual gliding, while true cleavage is obtained with 
 equal ease at all other parallel planes" (Moses and 
 Parsons, 149). 
 
 (d ) Slip planes : Those along which slip occurs (see Metal- 
 lography, page 282). 
 
 Crystal Cleavage. The separation or rupture of a crystal 
 along cleavage planes (see above) which represent directions of 
 minimum cohesion; also called intra-crystalUne or trans-crystal- 
 line rupture (cleavage brittleness), i.e., across or through the 
 grains or crystals, as distinguished from intercrystalline rupture 
 which occurs between them. "Cleavage is, in general, limited 
 to directions parallel to the simpler and more frequently occurring 
 crystal forms. In the isometric system it is parallel to the cube 
 
1 24 CRYSTALLOGRAPHY 
 
 (cubical), octahedron (octahedral) or dodecahedron (dodecahe- 
 dral). In the tetragonal system it is basal or prismatic and only 
 rarely pyramidal. In the hexagonal system it is basal, prismatic, 
 or rhombohedral, but rarely pyramidal. In the other systems 
 the arbitrary selection of axes prevents a simple classification of 
 cleavages, but the selection usually makes one direction of 
 cleavage pinacoidal and two of equal ease prismatic . . . 
 Cleavage is said to be perfect or eminent when obtained with 
 great ease, affording smooth lustrous surfaces. Inferior degrees 
 of ease of cleavage are called distinct, indistinct, or imperfect, 
 interrupted, in traces, difficult" (Moses and Parsons, 147). 
 Lateral and diagonal cleavages are those respectively parallel 
 to the lateral face and the diagonal plane. Certain metamorphic 
 rocks have their minerals or constituents segregated or deposited 
 (interpenetration) between the strata or grains, called joint 
 foliation where cleavage has occurred, or cleavage foliation 
 where rupture has been caused by bending (faulting foliation), 
 and when deposited as a layer (stratification foliation), such 
 surfaces of deformation are called foldings. 
 
 To indicate the property of cleavage special terms are used such 
 as: Lamination, to indicate that a substance is composed of 
 sheets which can be separated as such; fissile, of a crystal which 
 can be split; sectile, of a crystal which can be sliced, the slices 
 being friable or crumble readily. Different types of cleavage 
 are indicated by the terms heterotomous, unusual; orthotomous, 
 at right angles to each other; orthotypous, perpendicular. 
 
 Twinning. Twins or twin crystals, hemitropes or compound 
 crystals, are formed by the symmetrical intergrowth of two like 
 crystals; when the two individuals penetrate each other they 
 constitute a penetration twin, and when they do not, a contact 
 twin or juxtaposition twin (Moses and Parson, 65). Macle is 
 given (I.A.T.M.) as a synonym for twin crystal, but in mineral- 
 ogy it is the name of a mineral (chiastolite) having an internal 
 tesselated or cruciform structure (Dana). The twinning plane 
 (see above) is symmetrical to the two portions of the twin, but 
 is not a plane of symmetry for either alone. It may be consid- 
 ered that twinning has occurred by rotation of one portion 180 
 degrees about a line normal to the twinning plane, termed the 
 twin or twinning axis. In the case of contact twins the twinning 
 plane is also the contact plane, called the composition face, but 
 it is not the same with penetration twins. The crystalline 
 arrangement which produces a definite kind of twinning is called 
 the twinning law. There are a number of different types of 
 twin each of which has its own law. If there are only two indi- 
 viduals, it is called simple twinning ; if more than two, repeated 
 twinning. Multiple or polysynthetic twinning is repeated twin- 
 ning after the same law; crossed or grid-iron twinning (cyclic or 
 stellate twins), repeated twinning after two laws. If the indi- 
 viduals are connected in different ways, it is called a compound 
 twin. Twinning may occur (a} during crystallization (congenital 
 twins), (b) as a result of straining alone of crystals already 
 formed (mechanical twins), or (c) especially for iron, straining 
 
CRYSTALLOGRAPHY 1 2 5 
 
 followed by annealing (annealing twins). The structure on the 
 surface produced by twinning is a series of bands; from their 
 relative size annealing twins are also termed broad twins, while 
 mechanical twins are called narrow twins or Neumann lamellae 
 or Neumann bands. Pseudosymmetry is where the symmetry is 
 apparently of a higher form than normal, often due to twinning. 
 Crystalline Structure. The term structure (texture is used in 
 the same sense but should properly be restricted to woven fabrics) 
 refers to the arrangement and appearance, or organization, of the 
 different constituents of a substance. Rosenhain designates as 
 simple metals those composed of only one kind of crystals. A 
 body (and its structure) is said to be massive when it does not 
 show crystalline faces, whether it is crystalline or not (Moses and 
 Parsons). A crystalline aggregate is a body composed of coher- 
 ent crystals or grains which cannot be broken apart, i.e., are 
 not elastic. It is pseudocrystalline when apparently of a uni- 
 form crystalline formation, but really a composite of small 
 grains or pieces densely compacted. A porphyritic structure 
 consists of a semi-crystalline (partially crystalline) or finely 
 crystalline or glassy portion, appearing compact to the naked 
 eye, called the ground mass, matrix, magma, or base, in which 
 are embedded well defined crystals called phenocrysts. In 
 metallography these terms refer to the constituent which is 
 predominant. If the phenocrysts are absent, it is termed 
 felsitic ; granitoid or granulitic, composed of grains or crystals of 
 about the same size. An oolitic (egg-shaped) structure is one 
 made up of spherical individuals each of which has grown around 
 a nucleus, usually of some other material. A cored structure 
 has the interior or core of different structure or material from the 
 exterior. A poikilitic structure is composed of relatively large 
 crystals or grains which contain, without definite arrangement, 
 numbers of smaller individuals of various substances. A hemi- 
 pelic structure is one resembling fine clay; a fragmental structure, 
 one composed of pieces of a preexistent substance, or crystal 
 debris. A conglomerate is a structure composed of rounded 
 fragments; breccia structure is similar except the component 
 fragments are sharp. Columnar granulation, columnar structure, 
 or columnar crystals, is where the grains or the crystals are ar- 
 ranged in columns; in this sense the term prismatic is sometimes 
 applied to alloys; if the columns are very long and slender, as in 
 wrought iron, they are termed filaments or fibers, and the struc- 
 ture fibrous, fibriform, nerve, capillary (hair-like), or bacillar 
 (rod-shaped). A radiating structure is one consisting of lines 
 radiating from a common center; it is stellate when the radiations 
 are of equal length. Margarite structure (Vogelsang) is where 
 crystallites are arranged like strings of pearls. A spherulitic 
 structure, peculiar to vitreous rocks, and in eutectics of alloys 
 rapidly cooled, is so called because of the small spherulitic bodies, 
 or spherulites, they contain (I.A.T.M.). A structure is some- 
 times referred to as mushy when it has no distinct grains. Druse 
 (drusy cavity) is a term (corresponding to geode in geology) 
 used for a cavity formed during freezing, into which the ends of 
 
126 CRYSTALLOGRAPHY 
 
 crystals or crystallites project; needle-shaped crystals found in 
 druses are also -termed acicular. Certain terms referring to 
 minute forms simply add to the ordinary term (already given) 
 the prefix micro, and for which no further definitions are neces- 
 sary: microcrystallography, microcrystalline, microcrystallitic, 
 microgranular, micrpgranulitic, microgranitoid, micromeritic 
 (microcrystalline), microporphyritic, microspherulitic. Crypto- 
 crystalline or microcryptocrystalline, a structure of crystalline 
 particles too small to be detected by the naked eye. Cryptoclas- 
 tic, composed of fine grains broken apart from a preexistent form. 
 When it is composed of cells the following designating terms are 
 used: Monocellular or unicellular, one cell only; polycellular or 
 multicellular, many cells; homocellular, cells of the same kind; 
 heterocellular, cells of different kinds; microcellular, minute 
 cells; cryptocellular, cells so minute as to be invisible. A poly- 
 centric body or structure is one built up from many nuclei or 
 centers. A structure consisting of intersecting lines having the 
 appearance of a mesh or net is accordingly termed mesh, net, 
 network, lattice, reticular, reticulated, cancellated, or plaited 
 structure. If the meshes are of identical size and shape they may 
 be termed isodictyal. Howe refers to network as an assemblage 
 of walled cells (with a kernel contained within the envelope, 
 shell, or cell walls), and to network size as the average size of the 
 walled cells which make up the network (A.S.T.M., 1911-275); 
 he considers the term phenocellular for this structure as too 
 pedantic. A structure presenting the appearance of overlapping 
 plates is sometimes called imbricated. A thin plate, such as 
 graphite, is termed a lamella or lamina, and a structure composed 
 of or containing such plates, lamellar or laminated. 
 
 According to Osmond and Cartaud a body may be considered 
 both as cellular (having a network structure) and amorphous; 
 the former in so far as it is formed of polyhedral (many-sided) 
 grains, and the latter when the deformations are governed only 
 by the direction of the strains and are independent of the crystal- 
 line structure. Whence arise three kinds of deformation, which 
 they call crystalline, cellular and banal. Every deformation 
 has some sort of general configuration (deformation figure or com- 
 pression figure) which may be called its silhouette, and which is 
 the boundary of elementary deformations. It is the area of a pre- 
 viously polished body that loses its polish where the deformations 
 take place. A silhouette is naturally continuous and closed. 
 Its form on an ordinary metal with cellular structure depends 
 only on the form of the sample and on the nature or direction 
 of the strains; but it ceases to be the same on an isolated crystal, 
 for then its form can be in relation with the crystalline symmetry. 
 An observation of the lines of deformation on rupture shows that 
 under the influence of even sudden loads (impact) such lines 
 appear in nicked specimens inside the crystals; these Osmond 
 calls specific lines in contradistinction to the ordinary lines 
 produced by static stress. 
 
 If a surface composed of crystal faces or cleavages is attacked 
 by any solvent, the action proceeds most rapidly along certain 
 
CRYSTALLOGRAPHY 127 
 
 planes (solution planes) forming pits or depressions (etching pits) 
 of varying depths whereby characteristic figures (etching figures) 
 are produced. The term vesicle (or vesicular) should not be 
 applied to these as it refers to small approximately spherical 
 cavities commonly occurring in volcanic rocks. J. Czochralski 
 distinguishes three kinds of etching figure resulting from (i) 
 crystal-boundary etching, (2) crystal-field etching, and (3) 
 crystal-figure etching. Where a cavity resulting from etching 
 or from a gas bubble has the form of a crystal it is termed a 
 negative or internal crystal. Referring to the tripartite nature of 
 metals Howe says (Metallography, 268-9) that they are "(i) 
 microscopically crystalline, in that each microscopic grain is a 
 true crystal; (2) microscopically cellular, in that they are aggre- 
 gations of these grains, each of which may be regarded as a cell, 
 probably with an envelope; and (3) macroscopically amorphous, 
 because the orientation changes from grain to grain, and hence 
 the mass as a whole has no internal orientation of its own." 
 Where crystals with different orientation are in contact, Howe 
 refers to contact confusion of orientation as a reason why rupture 
 ordinarily avoids the joints. Howe refers (ibid., 275) to "what 
 may be called grains of two orders in ferrite, each large grain, or 
 grain of the first order, being made up of several fragments, 
 or grains of the second order, with the usual grain shape and 
 oriented alike." Rotation effect is a term used to describe the 
 lighting up and darkening of the crystalline grains in the etched 
 surfaces of polished metals when rotated before oblique rays 
 (Heycock and Neville) ; Ewing and Rosenhain refer to this as 
 the selective effect of oblique light (I.A.T.M.); more recently 
 Rosenhain suggests as preferable the term oriented lustre. 
 Schillerization "refers to the peculiar bronze-like lustre, "Schil- 
 ler," in certain minerals, due to the presence of minute in- 
 clusions in parallel positions" (Mellor). 
 
 When the surface or a section of certain alloys is polished (and 
 sometimes etched) there can be seen markings consisting of paral- 
 lel or intersecting lines or bands which have received different 
 names according to their structure. The structure produced 
 by narrow twinning (see above) has, after its discoverer, been 
 called Neumann bands, lamellae or lines. The Widmanstatten 
 or W structure or lines is discussed under Meteorites (page 291) ; 
 Sauveur suggests that it might be termed cleavage structure. 
 In discussing the deformation lines in manganese steel Howe 
 says (Metallog., 460) "The lines which form when this substance 
 is deformed may be divided into the surface bands which form on 
 previously polished surfaces, and the etching bands which are 
 developed by polishing and etching after deformation." Howe 
 terms manganese steel lines those peculiar to this type of steel 
 and differing from ordinary slip bands. What Howe calles X 
 bands "are rough striae found on polishing and etching iron which 
 has been severely deformed plastically . . . Their nature is not 
 known" (Metallog., 452). Eutectiferous bands or eutectiform 
 patterns are those caused by eutectics, usually observed after 
 etching in addition to polishing. Translation banding is what 
 
128 CUBIC SYSTEMCURVE 
 
 is due to movement but is distinguished from that produced by 
 twinning. "Thorns and boundary edgings (also called spikes 
 and bordered boundaries by Osmond, Fremont, and Cartaud) 
 are unexplained deep-seated markings developed occasionally in 
 low-carbon steel, but only by etching and only after plastic 
 deformation, and therefore clearly representing neither mechan- 
 ical defects nor local concentration of impurities" (Howe, 
 Metallog.,422). 
 
 What has been termed a metallic fog has been obtained, e.g., 
 by adding small pieces of metallic lead to fused colorless lead 
 chloride; dark colored crystals are formed on solidification with a 
 structure resembling that of gold ruby glass. A colloidal metal 
 is referred to as one which is so finely divided it will remain 
 indefinitely in suspension in water; in this condition colors are de- 
 veloped differing from that of the ordinary form; the precious 
 metals have been those principally studied in this connection. 
 
 Cubic System. Of crystallization: see page 120. 
 
 Cubical Cleavage. See page 124. 
 
 Cuboid; Cuboidal. See page 122. 
 
 Cull. A piece of rejected material. 
 
 Culm. See Coal. 
 
 Cumberland Process. See page 365. 
 
 Cumulative Class. In hardening: see page 279. 
 
 Cuneate; Cuneiform. See page 122. 
 
 Cunningham's Formula. For tensile strength: see page 338. 
 
 Cup and Cone. See page 32. 
 
 Cup Fracture. See page 1 79. 
 
 Cupola. See page 182. 
 
 Cupola Crucible. See page 182. 
 
 Cupola Furnace. (i) See page 182 ; (2) a name formerly given to a 
 small blast furnace built ol brick and bound with bands. 
 
 Cupola Metal. Molten pig iron, obtained by melting in a cupola. 
 
 Cupping. (i) A defect in wire which causes it to break with a cup 
 fracture; (2) pressing a sheet or plate into cup form, as in the 
 manufacture of one kind of seamless tubing; also called dishing: 
 see page 101. 
 
 Cupric Reagents. For etching; those containing some salt of 
 copper: see page 287. 
 
 Cure. In rolling: see page 412. 
 
 Curing Color. See page 371. 
 
 Curve. Also called graph ; a diagram to illustrate graphically the 
 relative change or changes between two (or three) conditions 
 affecting a body, when one or more of these conditions varies; 
 further, to obtain, by interpolation, any relation, within a given 
 range, from a number of relations actually determined. The 
 usual method is to lay off a vertical line near the left-hand 
 margin of a sheet of paper, intersecting, usually at right angles, 
 a horizontal line near the bottom; these lines are called the axes, 
 and they determine the location and the shape of the curve by 
 means of perpendicular distances from them, called coordinates. 
 Where the axes intersect is the zero point or origin. Divisions 
 on the axes represent units of the related conditions. For ex- 
 
CURVE 
 
 129 
 
 ample, in the case of the effect on tensile strength produced by 
 changes in carbon content, the vertical axis will represent pounds 
 per square inch, and the horizontal axis, percentages of carbon. 
 The tensile strength and the carbon content of a specimen having 
 been actually determined, from the point on the vertical axis 
 corresponding to the tensile strength obtained a line is drawn at 
 right angles until it intersects another line drawn at right angles 
 from the point on the horizontal axis representing the known 
 percentage of carbon, the intersection giving one point of the 
 curve. A number of other points have been similarly plotted, 
 they are connected by a line, called a curve, which may be straight, 
 broken, or curved. Any point on this curve is called a locus 
 (plural, loci), the perpendicular distance of which from the 
 
 PIG. 14. Triaxial diagram. 
 
 
 
 vertical axis is termed the abscissa ; that from the horizontal 
 axis, the ordinate. A sudden change in the shape of a curve is 
 called a jog, break, or perturbation, and the curve is said to be 
 discontinuous : a curve which is smooth or regular is called 
 continuous or jogless. 
 
 Assigning values to a point on a curve is termed interpolation 
 if such points lies within limits actually determined; extrapola- 
 tion if it lies outside such points, the assumption being that for a 
 certain distance at least there will be no sudden change in the 
 nature or form of the curve and the corresponding values. The 
 first method is of course much less liable to error than the second. 
 
 A cooling curve shows the rate of cooling of a body plotted with 
 degrees of temperature and units of time as coordinates. The 
 diagram similarly obtained by heating is known as a heating 
 curve. A solubility curve shows the percentage of a substance 
 which is dissolved at different temperatures. An equilibrium 
 
130 CUT BAR IRON CYCLIC TWIN 
 
 curve (see page 326) shows the relation between temperature and 
 composition of a heterogeneous system, in which the phases 
 present are in equilibrium with each other (I.A.T.M.). A 
 freezing-point curve, melting-point curve, or fusion curve 
 represents the variation in the temperature of freezing (or melt- 
 ing) of a series of alloys corresponding to changes in composition. 
 The triaxial diagram is designed to show graphically the 
 relation between three variables whose sum is a constant quantity 
 (e.g., percentages). As shown in the sketch, the loci are obtained 
 by the intersection of vertical lines drawn perpendicular to the 
 three axes AB, AC, and DE. 
 
 Cut Bar Iron (rare). (Wrought) iron bars cut for crucible melting. 
 
 Cut Out. Of linings, etc., corroded. 
 
 Cutaneous Blowholes. See page 55. 
 
 Cutlery Temper. See Temper. 
 
 Cutting. Of slags, flames, or gases, oxidizing. 
 
 Cutting Blast. See Blast. 
 
 Cyano -nitride of Titanium. See Salamander. 
 
 Cyclic Twin. See page 124. 
 
D 
 
 Dy. Chemical symbol for dysprosium: see page 84. 
 
 Daelen Mill. See page 408. 
 
 Daelen Process. See page 63. 
 
 Daelen-Pszczolka Process. See page 317. 
 
 Dalton's Law. See page 85. 
 
 Dam; Dam Plate; Dam Stone. Of an old-style blast furnace: see 
 page 32. 
 
 Damascus Steel. A metal formerly made at Damascus, by some 
 direct process, covered with beautiful figurations (damaskeening), 
 principally used for sword blades and gun barrels. Very good 
 imitations are now made in France and elsewhere. These are 
 produced by welding together bars or strips of wrought iron and 
 (wrought) steel in different ways to obtain the desired pattern. 
 After being given the final shape, the surface is etched with acid 
 or other substance, leaving part bright and part dark, or of differ- 
 ent colors. A cheap imitation consists in taking a piece of ordi- 
 nary iron or steel, and pasting on it a sheet of paper on which is 
 printed a pattern. Upon etching, the portion covered by the 
 printing is not attacked. The original steel contained tungsten, 
 nickel, manganese, etc. 
 
 Damask Steel ; Damaskeening ; Damasking. See Damascus Steel. 
 
 Damped Down. Of a blast furnace: see page 37. 
 
 Daniels Mill. See page 420. 
 
 Darby Recarburizing Process. See Recarburization. 
 
 Dasymeter. An instrument for measuring loss of heat in a furnace 
 by analysis of the waste gases. 
 
 Datum Points. See page 473. 
 
 Daubreelite. See page 292. 
 
 Davy Portable Converter. See page 23. 
 
 Davy Process. See page 19. 
 
 Day Gas Pyrometer. See page 207. 
 
 De Dion-Bouton Process. See page 70. 
 
 De Laval Feeding Head ; Ring. See page 60. 
 
 De Laval Process. See page 140. 
 
 De Lisle's Scale. Of temperatures: see page 205. 
 
 De Marre Formula. See page 8. 
 
 De Vathaire Process. See page 385. 
 
 De Wees Wood Process. See page 369. 
 
 Dead. (i) Molten steel which is perfectly quiet, i.e., does"not 
 evolve gas: see page 114; (2) steel which has been burnt or 
 contains high sulphur, so that, on rolling or forging, it cracks 
 or breaks up: see page 226. 
 
 Dead Annealing. See page 232. 
 
 Deadhead. See page 56. 
 
 Dead Load. See page 468. 
 
 Dead Melt; Melted, Molten. Of materials in a furnace, etc., 
 fully or completely melted, and from which no gas is being 
 evolved; killed. 
 
132 DEAD OFF THE BOIL DEPHOSPHORIZATION 
 
 Dead Off the Boil (Eng.). When no more carbon is left in a metal- 
 lic bath. 
 
 Dead Pass. See pages 405 and 420. 
 
 Dead Roller. See page 407. 
 
 Dead Soft Annealing. See pages 232 and 509. 
 
 Dead Soft Steel. See page 455. 
 
 Dead Steel. Steel, page 144. 
 
 Dead Weight Test See page 477. 
 
 Dean Process. See Hardening. 
 
 Decalescent Point. See page 265. 
 
 Decarbonization. See page 382. 
 
 Decarburization. See page 382. 
 
 Decarburizing Process. For malleable castings: see page 258. 
 
 Decomposition. See page 89. 
 
 Decremental Hardening. See pages 9 and 228. 
 
 Decrepitation. The action of certain salts or minerals when small 
 fragments fly apart with a cracking sound on being heated. 
 
 Decrystallization. See page 281. 
 
 Deep Seam. See page 489. 
 
 Deep-seated Blowholes. See page 55. 
 
 Defective (noun Eng.). Waste or scrap material. 
 
 Defective Welds. See page 502. 
 
 Deficit Substance. See page 266. 
 
 Definite Alloy. See page 4. 
 
 Definite Proportions, Law of. See page 84. 
 
 Deflection. Under drop test: see page 481. 
 
 Deflection Tests. See page 477. 
 
 Deflocculated. Brought to an extremely fine state of division. 
 
 Deformation. (i) General: see page 126; (2) energy of: see page 
 481. 
 
 Deformation Figure. See page 126. 
 
 Deformed Bar. Bars of irregular section used in reinforced con- 
 crete construction. 
 
 Degree of Heat. See page 199. 
 
 Degasified. See page 55. 
 
 Deighton Converter. See page 23. 
 
 Deliquesce ; Deliquescence. See Water. 
 
 Delivery. Of patterns: see page 296. 
 
 Delta (5) Iron. See page 272. 
 
 Demenge Process. See page 8. 
 
 Dempster Process. For the recovery of tar and ammonia from the 
 gas of a blast furnace using raw coal. 
 
 Dendrite; Dendritic Crystal. See page 55. 
 
 Dendritic Interlocking. See page 282. 
 
 Density. Or specific gravity; the ratio between the weight of a 
 unit volume of a given substance and that of a unit volume of some 
 other substance taken as a standard under standard conditions 
 of temperature and pressure. The specific gravity of solids and 
 liquids is found by dividing their weight by that of an equal 
 volume of water. For gases, air or hydrogen is taken as the 
 standard. 
 
 Dephosphorization. See page 382. 
 
DEPOSITION METHODS DILUTION 133 
 
 Deposition Methods of Etching. See pages 286 and 288. 
 
 Depuration (rare). Purification. 
 
 Desch's Iron -Phosphorus Diagram. See page 272. 
 
 Deseaming Process. See page 418. 
 
 Deshayes' Formulae. For elongation: see page 338. 
 
 Desiccation. See pages 30 and 499. 
 
 Desiliconization. See page 382. 
 
 Destructive Distillation. Distillation in a closed retort, i.e., 
 without access of air. It is applied to carbonaceous material 
 from which it is desired to drive off the volatile matter without 
 allowing combustion to take place, or only to a very limited 
 extent. 
 
 Destructive Test. See page 467. 
 
 Desulphurization. See page 382. 
 
 Detail Fracture. See page 179. 
 
 Detinned Scrap. Tin-plate scrap from which nearly all of the tin 
 has been removed. 
 
 Detmold Process. See page 385. 
 
 Detrusion. See page 337. 
 
 Devil. See page 298. 
 
 Dezincification. See page 106. 
 
 Diagonal Cleavage. See page 124. 
 
 Diagram. See Curve. 
 
 Diameter. In measuring magnifications. 
 
 Diamond. Form of carbon : See Carbon. 
 
 Diamond Pass. See page 405. 
 
 Diamond Rolling. See page 412. 
 
 Diamond Theory. Of hardening: see page 280. 
 
 Diatomaceous Earth. See page 396. 
 
 Diatomic. See page 87. 
 
 Dibasic. See page 87. 
 
 Dick Process. A process for making all kinds of metallic sections, 
 especially those difficult to roll or forge, by forcing hot and plastic 
 metal through a die. 
 
 Die. In forging: see page 195. 
 
 Die Plate. In wire drawing: see page 507. 
 
 Die Temper. See Temper. 
 
 Diehl-Faber Process. See page 97. 
 
 Differential Cooling. See page 228. 
 
 Differential Freezing. See page 266. 
 
 Differential Hardening. See page 228. 
 
 Differential Heating. See page 228. 
 
 Differential Thermometer. See page 205. 
 
 Differential Thermoscope'. See page 205. 
 
 Differentiation. In segregation: see page 56. 
 
 Difficult Cleavage. See page 1 24. 
 
 Diffusion. (i) General: see Solution; (2) of carbon in solid solu- 
 tion: seepage 213. 
 
 Dilatation. Expansion or distension. 
 
 Dilatation Method. For determining critical points: see page 265. 
 
 Dilatometer. See page 483. 
 
 Dilution. In cementation: see page 70. 
 
134 DILUTION PYROMETERS DIRECT PROCESSES 
 
 Dilution Pyrometers. See page 210. 
 
 Dimetric System. Of crystallization: see page 120. 
 
 Diminution. Lessening or reduction. 
 
 Dimorphism. See page 121. 
 
 Dinas Brick. See page 395. 
 
 Dip Roof. The depressed (concave) roof first adopted for open 
 hearth furnaces, since superseded by the present convex roof. 
 
 Dipping. Of tin plates: see page 432. 
 
 Direct. Without any intermediate stage or condition, e.g., direct 
 process, where the ore is reduced to malleable iron or steel with- 
 out first being made into cast iron. 
 
 Direct Bloom. Made by some direct process. 
 
 Direct Driven Rolls. See page 407. 
 
 Direct Firing Stove. See page 34. 
 
 Direct Heating Furnace. See page 181. 
 
 Direct Metal. See page 36. 
 
 Direct Ore Process. See below. 
 
 Direct Process. (i) Sometimes applied to the use of direct metal, 
 but undesirably; (2) for by-product recovery: see page 96. 
 
 Direct Processes. (i) Those in which wrought iron or spongy iron 
 is made directly from the ore, and either used as such or converted 
 into steel, usually by melting it with cast iron, more rarely by 
 cementing it with carbonaceous matter, or in which weld or even 
 ingot steel (low or high-carbon steel) is made directly from the 
 ore (Howe), sometimes referred to as direct ore process; (2) 
 rarely, the use of direct metal in connection with the open hearth 
 or the Bessemer process. 
 
 Direct processes may be classified (Howe) according to: 
 
 I. Temperature: 
 
 (a) Sponge making processes: where the temperature 
 is so low that, while the iron is reduced, it is not 
 thoroughly welded together. 
 
 (b) Balling heat processes: where the temperature is 
 sufficient to allow the iron to ball or weld together. 
 
 (c) Steel melting heat processes : where the temperature 
 is sufficient to melt the product. If in a shaft furnace, 
 cast iron results. It is applicable only in a reverbera- 
 tory furnace or a crucible. 
 
 II. Action of fuel: 
 
 1. Heating fuel also serves for deoxidation: 
 (a) Solid fuel. 
 
 (&) Gaseous fuel. 
 
 2. Separate fuel used for deoxidation. 
 
 (c) Ore is enclosed in externally heated retorts. 
 
 (d) Heated by a current of hot gas passing through 
 it. 
 
 (e) Treated in open reverberatories. 
 
 The furnace principally used was of various types and modifica- 
 tions, and was called a bloomary (sometimes bloomery, block 
 oven, block furnace) or forge. Forge was also the name used 
 for the heating furnace and the hammer, or for the whole plant 
 
DIRECT PROCESSES 1 3 5 
 
 consisting of the furnace, a blowing engine, and a hammer. 
 "The sides are iron plates, the hair plate at the back, the cinder 
 plate at the front, the tuyere plate (through which the tuyere 
 passes) at one side (its upper part being called in some bloomaries 
 the merrit plate), the fore-spar plate opposite the tuyere plate 
 (its upper part being the skew plate), and the bottom plate at the 
 bottom. The boot is the joint connecting the tuyere or nozzle 
 with the blast main, usually made of tin or leather. The tongs 
 with which the blooms are handled were called (U.S.) grampus" 
 (Raymond). 
 
 A type originally like the stiickofen (see below), but later used 
 for producing either wrought iron or cast iron, and resembling a 
 crude blast furnace, was termed blauof en, blau furnace, or blue 
 furnace ; a flussof en was strictly a primitive blast furnace. 
 
 The product, extracted as a lump of wrought iron mingled 
 with slag, was called a loup (loop), bloom or ore bloom, but 
 sometimes the two latter terms were applied only after it had 
 been worked; ancony was the old name for a bloom which had 
 been partly worked under a hammer. EncrenSe (Fr.) is the 
 first shape given to a bar of iron from the forge. The mass is 
 forged down in the middle to the dimensions of the finished bar, 
 leaving both ends unforged (ancony). A marquette d'encrenee 
 is an encr6n6e with one of the ends forged. These definitions are 
 given by Grignon (Osmond). In the most carburized bars from 
 direct steel, when the drawing out (under the hammer) has not 
 been pushed very far, there develop under these conditions a 
 great number of small, fine transverse cracks, on the walls of 
 which can be seen, after breaking, concentric zones formed by the 
 temper colors. The name roses is given to these colorations, and 
 rose steel to the metal. This is forged and then quenched 
 while still hot to classify it by the fracture; the less carburized 
 it is the coarser the grain (Resser). 
 
 "No forges for the manufacture of blooms and billets direct 
 from iron ore have been in operation in the United States since 
 1 901, in which year the blooms and billets so made amounted to 
 2310 gross tons, against 4292 tons in 1900 and 3142 tons in 
 1899. All the Catalan forges in the South have been abandoned; 
 so have those in the North and West." (Annual Statistical Re- 
 port of the American Iron & Steel Association, 1908, p. 78). 
 
 The production of malleable iron direct from the ore has proved 
 a most attractive field for metallurgists and inventors, and many 
 attempts have been made to devise a process^ which would 
 accomplish, in one operation, the same result which is obtained 
 by the blast furnace combined with some one of the refining proc- 
 esses. As a matter of logic it does not seem reasonable to pro- 
 duce iron containing a greater proportion of carbon and impuri- 
 ties than is desired, and subsequently remove the excess. The 
 difficulties have been that in the direct process the product can- 
 not be obtained in a fluid state as carbon is then greedily taken up, 
 and this, on account of its cheapness and availability is practi- 
 cally the only substance used for reduction and heating. Mate- 
 rials in a solid, more particularly in a pasty and hot condition, 
 
136 DIRECT PROCESSES 
 
 cannot compare, in ease of handling, with fluids, and this alone 
 would be sufficient to account for the lack of success with which 
 direct processes have met. Furthermore, few ores are sufficiently 
 pure to permit of their use for direct processes without prelimi- 
 nary treatment. 
 
 The principal advantages and disadvantages may be summar- 
 ized as follows: .. 
 
 Advantages : 
 
 (a) An iron nearly free from carbon in one operation. 
 
 (b) Removal of phosphorus, but at a heavy cost of iron. 
 | . '. (c) Employment of cheap fuel. 
 
 Disadvantages : 
 
 (d} Product not fluid. 
 
 (e) Loss of iron through reoxidation or imperfect deoxidation. 
 
 (/) Heterogeneousness and carburization of product. 
 
 (g) Absorption of sulphur. 
 
 (h) Heavy outlay for labor. 
 
 (i) Rich and cheap ores necessary. 
 
 As, in most cases, heating and reduction are performed by the 
 fuel in contact with the ore, there is danger where, as in the case of 
 the old high bloomary, the height of the furnace is considerable, 
 that not only will the ore be reduced, but also carburized to 
 such an extent as to produce cast iron. After the iron has been 
 reduced to the metallic state it will absorb carbon, depending on 
 the length of time it is in contact with the fuel and on the tem- 
 perature. It is therefore necessary to keep the furnace from get- 
 ting too hot, and also to hasten the operation as much as possible. 
 
 If a considerable amount of the ore is not reduced, the resultant 
 slag is very basic, and consequently possesses the property of 
 holding most of the phosphorus and preventing it from being 
 reduced and taken up by the metallic iron. On the contrary, 
 when reduction is strong, there will be less iron in the slag which 
 will, accordingly, be less basic, and phosphorus is then reduced. 
 
 Another advantage, viewed from the standpoint of quality but 
 not of cost, of having the slag very basic, is that less sulphur is 
 absorbed by the metal. While the charge is descending, any 
 pyrites will be partially roasted, and will lose one atom of its 
 sulphur: 
 
 FeS 2 + O 2 + Heat = FeS + SO 2 
 
 The other atom of sulphur will not be much affected on account 
 of the excess of carbon present, which of course tends to make a 
 reducing, and not an oxidizing, atmosphere. The remaining sul- 
 phur will be largely taken up by the metal, depending consider- 
 ably on the nature of the slag. With sulphur dioxide in the 
 products of combustion, the reaction may occur: 
 
 SO 2 + 2 C = S + 2 CO 
 
 The necessary carbon may be obtained either from the fuel or 
 from that in the metal itself. 
 
 It should be noted that, in direct processes, the phosphorus is, 
 
DIRECT PROCESSES 1 3 f 
 
 to a great extent under control, and that the sulphur is not, while 
 just the reverse is true of the blast furnace. In the latter case, a 
 large amount of lime is charged to remove the sulphur, and as the 
 resultant slag is very infusible, a high temperature is required, 
 and, consequently, all the iron and phosphorus are reduced and 
 the former is highly carburized (after Howe). 
 
 In the Adams process (sometimes called Blair-Adams process) 
 ore in lumps 3" cube and smaller, sometimes mixed with about 5 
 % of solid fuel, and in vertical chambers above an open hearth 
 furnace, is heated and reduced by a current of hot gas. It passes 
 thence, either continuously or, better, one chamberful at a time, 
 into a chute, and thence into a bath of molten cast iron in the open 
 hearth furnace, diluting and probably also oxidizing the carbon 
 and silicon of the bath, quite as in common open hearth practice 
 (Howe). 
 
 The American bloomary process (American forge or Cham- 
 plain forge), resembling the Catalan process in its general fea- 
 tures, differs from it in that the ore is charged wholly in a fine 
 state and mixed with charcoal, instead of chiefly in lumps and in 
 a separate column (Howe) . The furnace is somewhat higher, and 
 the bottom plate is of cast iron water-cooled. 
 
 In A. E. L. Belford's process the ore, pulverized and well mixed 
 with charcoal or other carbonaceous matter, and with or without 
 the addition of fluxes, is heated in a tubular or other suitably 
 shaped vessel. It is then transferred, with as little cooling as 
 possible, to crucibles and melted down. In a modification, where 
 the initial product is -evidently obtained in a fused and carburized 
 condition, it is transferred by a closed runner to a decarburizing 
 chamber, heated from without, where it is acted upon by decar- 
 burizing gases or steam. 
 
 In the Berner process a special shaft furnace is employed with 
 tuyeres at different levels, and divided into two parts by a verti- 
 cal partition. On one side ore is smelted to pig iron with solid 
 fuel, while on the other, ore is reduced to spongy iron with reduc- 
 ing gases. The spongy iron is dissolved in the mloten pig iron at 
 the bottom, diluting the impurities to form a sort of steel which is 
 run into a reverberatory furnace, forming a fore-hearth to the 
 shaft furnace, where the treatment is completed. 
 
 The Blair process, also called Blair's iron sponge process, is 
 an improvement over Chenot's process, in which small lumps of 
 ore mixed with charcoal are heated externally in a retort about 
 4% feet in diameter and 40 to 50 feet high, the heating taking 
 place at the top, the sponge then descending into a cooling cham- 
 ber, and being finally taken out at the bottom. Later Blair dis- 
 covered that the addition of about 5 % of lime to the ore greatly 
 hastened deoxidation. The earlier apparatus consisted of three 
 vertical retorts, but in the later form there was only one, and 
 producer gas was used to heat, first externally, and then near the 
 top, by passing directly through the ore. There was the cooling 
 chamber as before. The sponge when drawn from the reducing 
 furnace was quite cool, so that it did not reoxidize. It was 
 squeezed under a pressure of 30,000 pounds to the square inch into 
 
138 DIRECT PROCESSES 
 
 cylindrical blooms. Later only the fine sponge was compressed, 
 the lumps being shoveled into the open hearth furnace, for which 
 all the material was designed to replace scrap. He also combined 
 the sponge with charcoal or tar to lessen the proportion of cast 
 iron needed in the open hearth process (Howe). 
 
 Bull's process: This so-called direct process was hardly one 
 at all, but rather an ill-advised attempt to replace the whole of the 
 solid fuel of the blast furnace with superheated water gas (Howe). 
 
 The Cadinho furnace is cylindrical and of circular or slightly 
 oval section, about 3 feet high and i foot in diameter (inside), 
 and has one tuyere with air supplied by a trompe. The furnace 
 is filled with charcoal, and after it is ignited and the furnace hot, 
 alternate layers of charcoal and moistened powdered ore are in- 
 troduced. After blowing for about i% to i% hours the fire is 
 allowed to go down and the bloom is extracted through a hole at 
 the bottom. The reduction is very imperfect, the yield being 
 about 22% of the ore. 
 
 The Carbon Iron Company's process (Iron Company's process) : 
 Iron ore is deoxidized on the carbonaceous hearth of an open 
 reverberatory furnace by means of graphitic anthracite or 
 retarded coke (see Coke) with which it is mixed. These reducing 
 agents, in that they themselves become oxidized only very slowly, 
 indeed reduce the iron less rapidly than charcoal or common coke; 
 but after reduction is effected they resist oxidation, and so persist 
 and remain to protect the reduced iron from oxidation. The 
 reduced iron is then balled and put in an open hearth furnace, or 
 squeezed for rolling into wrought iron (Howe). Blooms made by 
 this process were called carbon blooms or sponge blooms. The 
 original process (Eames process) employed Rhode Island graph- 
 itic carbon, and in its later form had a number of modifications, 
 including moistening the carbonaceous reducing material with 
 lime or some similar inert substance to retard its oxidation. 
 
 Catalan process or Catalan forge process : The furnace usually 
 consists of an open hearth of about 28" depth to the rear wall, 
 and 30" width, and provided (usually) with one tuyere inserted 
 2 feet below the level of the top of the fuel. The casing is of 
 cast iron, double and water-cooled. Above the hearth is a stack 
 to carry away the products of combustion. The hearth is open 
 at the front like an ordinary open fireplace. The blast is supplied 
 under a pressure of from i% to 2 pounds per square inch, and 
 heated to a temperature rarely if ever measured but generally sup- 
 posed to be 600 to 800 F. (315 to 430 C.). The heating pipes 
 are bent U-shaped tubes placed in the stack. The tuyere is 
 either pointed horizontally or slightly inclined downward. The 
 furnace is first filled with charcoal, which is lighted, and the blast 
 turned on. When the whole is well ignited, the ore, calcined and 
 coarsely pulverized, is sprinkled with a shovel over the surface of 
 the fuel in small quantities, and at short intervals basketfuls of 
 charcoal are added as the fire burns down. The ore is deoxidized 
 by the fuel as it works downward, and the*metal finally collects in 
 an unfused pasty mass at the bottom of the hearth, like a great 
 sponge. The cinder fills its pores as a liquid bath, and is tapped 
 
DIRECT PROCESSES 
 
 139 
 
 off occasionally at the front. A mass of iron weighing about 300 
 pounds is formed in about 3 hours. This is lifted out from under 
 the fuel and is worked under a hammer into a bloom or loup which 
 is reheated when necessary at the charcoal fire. One furnace or fire 
 is expected to yield from i ton to 2500 pounds per day. About 
 3500 to 5000 pounds of charcoal, and i?$ to i% tons of selected 
 ore (equivalent to from 2^ to 4 tons of ore as mined) are used 
 per ton of blooms (Thurston). 
 
 FIG. 15. Catalan forge (Thurston, "Iron and Steel"). 
 
 In Chenot's process washed or pure ore, agglutinized with 
 some pasty substance (e.g., 3 % of resin) and mixed with a slight 
 excess of charcoal, was charged in vertical rectangular retorts 
 about 28^ feet high, 6^ feet long, and i K feet wide, the width in- 
 creasing slightly at the bottom. The upper part was of fire-brick 
 surrounded and heated by a series of vertical flues, connecting 
 at the bottom with fireplaces, and open at the top. The bottom 
 was of sheet iron, water- jacketed to receive and keep the sponge 
 out of contact with the air until cold. The operation was con- 
 tinuous. In a later method he reduced and heated the ore by 
 passing through it a current of hot carbonic oxide (producer gas) 
 in the same style of apparatus. 
 
 In Clay's process red hematite ore, crushed to lumps not larger 
 than a walnut, was mixed with one-fifth its weight of charcoal or 
 other carbonaceous matter and subjected to a bright red heat in 
 clay retorts, etc., until the iron was reduced to the metallic state. 
 The sponge so produced was then transferred to a puddling fur- 
 nace, with or without the addition of 5 % of coke, where it was 
 balled. The process was slow and costly, and the iron produced 
 
140 DIRECT PROCESSES 
 
 Was frequently red short. He also mixed ore with half its weight 
 of coal, etc., and heated it in a puddling furnace with four times 
 its weight of pig iron (Percy). 
 
 In the Conley process crushed and magnetically concentrated 
 ore is mixed with carbon and heated in closed retorts (heated 
 externally), the ore and the reducing agent being stirred con- 
 tinually. The partially reduced ore is transferred to iron cases 
 where it is allowed to cool out of contact with the air and is 
 then mixed with a small percentage of pitch, molded into bricks 
 and melted down. In a later modification (Conley -Lancaster 
 process) the ore, in heated retorts, is reduced by intermixed 
 solid carbonaceous matter, or by a gas which is led through the 
 retorts, after which the sponge is transferred to an open hearth 
 furnace with as little exposure to the air as possible. 
 
 Edward Cooper process : Iron ore in a column is heated and 
 reduced by a current of hot carbonic oxide, or carbonic oxide 
 and hydrogen. These gases are oxidized to carbonic acid 
 and steam by the oxygen of the ore: they are then passed through 
 a regenerator, in which they are highly heated, and thence 
 through a bed of coal or other fuel in which they are again 
 deoxidized to carbonic oxide and hydrogen. Still remaining in 
 the same closed circuit, they are then used for reducing a fresh 
 portion of the ore, a part of the carbonic oxide and hydrogen, 
 however, being diverted to heat the regenerator already men- 
 tioned (Howe). 
 
 The Corsican process is similar to the Catalan, but very 
 much cruder. The furnace is really a blacksmith's forge with 
 one tuyere. About 10 cwts. of ore are placed on the side away 
 from the tuyere and moistened crushed charcoal is packed 
 between. Care is taken at first not to melt the ore. Charcoal 
 is thrown on at intervals, and finally the reduced sponge is melted 
 down, and the bloom extracted, hammered, etc. The process 
 takes about 24 hours and uses about 9 parts by weight of char- 
 coal to i of iron produced, and the loss of iron is about 30%. 
 
 The De Laval process consists in heating a mixture of pul- 
 verized ore and carbonaceous matter in a rotating cylinder, 
 and then bringing it in contact with a powerful electric arc 
 to reduce the iron to the metallic state. The melted iron is 
 transferred into a large and highly heated furnace where it 
 can be directly made into steel, or from which it can be cast 
 into molds for further treatment. 
 
 In the Du Puy process about 116 pounds of ground iron ore, 
 mixed with carbonaceous matter for reduction and with suitable 
 fluxes to scorify the gangue, is enclosed in annular sheet-iron 
 canisters about 13" high, 15" in diameter, and weighing 6 pounds. 
 The charged canisters are heated to bright whiteness (a welding 
 heat) for from 5^ to 10 hours on the coke-covered hearth of a 
 common open reverberatory furnace. The reduced metal, 
 still in its canister, may, according to Du Puy, be converted 
 into muck bar by hammering or squeezing and rolling and then 
 cut up and treated by the crucible process: it may be charged at 
 once in the open hearth process with or without (?) cast iron; 
 
DIRECT PROCESES 141 
 
 or it may be melted down with cast iron in the furnace in which 
 it has been reduced (Howe). 
 
 In J. G. von Ehrenwerth's process high carbon iron (pig 
 iron) is melted at a high temperature in an open hearth furnace; 
 ore is added, the iron in which is reduced by the carbon of the 
 bath and dissolved by the bath, which is recarburized with solid 
 carbon in the furnace itself, or in a pan, or in a small blast furnace. 
 Ore is again allowed to act on the carburized material, and the 
 process is repeated until the requisite amount of iron is produced. 
 The slag which is poor in iron is removed from time to time. 
 The higher the temperature, the more satisfactory is the 
 operation. 
 
 In the Eustis process briquettes, made by coking fine ore 
 with bituminous coal, were to be melted in a cupola, with the 
 idea that the phosphorus would not be reduced, but the tendency 
 would be to reduce the phosphorus and also to produce cast iron. 
 
 In the Gerhardt process, briquettes composed of ore, flux, 
 carbonaceous matter, and tar were heated in a puddling furnace, 
 the reduced iron being balled, etc. 
 
 The German bloomary was like an early form of Catalan 
 forge. The product was sometimes termed German steel, 
 although this name was also applied to wrought iron produced 
 by refining pig. 
 
 The Graff process appears to be practically the same as 
 the Iron Company's process. Coarsely pulverized coke, treated 
 with a wash of lime or clay, is mixed with ore and heated, on the 
 hearth of a reverberatory furnace lined with coke, at a tempera- 
 ture sufficient to slag off the gangue. The iron may be balled 
 or transferred direct to the bath of an open hearth furnace. 
 
 G. Gunther's process consists in (i) the reduction of finely 
 divided ore by solid carbon at a low temperature to avoid slag- 
 ging off any unreduced ore; (2) the transfer to a receptacle filled 
 with reducing gases to complete the reduction; and (3) fusion of 
 the reduced iron with coke and fluxes in a shaft furnace. 
 
 The Gurlt process consisted in deoxidizing iron ore and car- 
 burizing (?) the resulting sponge in the central shaft of a special 
 type of furnace by passing through it a stream of hot producer 
 gas from producers forming part of the furnace. Here the 
 producer gas both heats and deoxidizes the ore which is unmixed 
 with solid fuel. The hot spongy iron was drawn through a 
 doorway at the bottom of the shaft, to be balled, or, if highly 
 carbureted, to be melted, in an open hearth furnace or in a char- 
 coal hearth (Howe). 
 
 The Harvey process, similar to Renton's, consisted in heating 
 coarsely powdered ore with charcoal on inclined steatite shelves 
 connected with a balling furnace, and heated by a passing flame. 
 The deoxidized ore was transferred to the hearth of the balling 
 furnace and balled (Howe). 
 
 Hawkins process was to cement (heat) iron ore in lumps 
 surrounded with charcoal. 
 
 Gustave Hofer's process employs a special type of furnace 
 having the shape of a truncated cone with the smaller end 
 
142 DIRECT PROCESSES 
 
 downward, and mounted on trunnions so it can be tipped. It is 
 lined with refractory material, and inside is a separate refractory 
 chamber between which and the lining are a number of gas 
 passages. This inner or reducing chamber is provided with two 
 pipes, an upper for tapping the slag, or the iron by tipping the 
 furnace, and a lower one for introducing gases, and for tapping 
 the iron. The main or outer vessel is provided with inlets for 
 
 is and air which burn and go up through the gas passages. 
 re and coal are charged in the reducing chamber, and are heated 
 by the burning gases on the outside. When the reduction and 
 smelting are complete, the slag is tapped off, the valve in the 
 bottom of the furnace opened, and gases blown into the bath 
 of metal to purify it. The furnace may also be fired from the 
 outside. 
 
 Husgafvel's high bloomary or continuous stiickofen was a 
 tall shaft furnace about 26 feet high, with double air-cooled 
 walls between which the blast was preheated. It had a movable 
 hearth with four water-cooled tuyere holes on each of the two 
 opposite sides on two levels. The blast was introduced in the 
 lower holes first and, as the hearth filled up, these were plugged 
 up and the upper ones used. When the hearth was filled up to 
 these, the blast was stopped and the hearth removed. A fresh 
 hearth was put in place and the process continued. 
 
 The Imperatori process consists essentially in adding briquettes 
 of iron ore and coal to the bath of metal in an open hearth furnace. 
 
 The Ireland process has to do with melting sponge in a cupola 
 furnace. 
 
 The Irving process is conducted in an electric furnace. A 
 continuous shower of ore (fine magnetite) and limestone is passed 
 from an upper stack through a reduction chamber, in which the 
 ore is partly reduced by ascending carbon monoxide, to a crucible 
 at the bottom in which the reduction is completed by means of 
 finely powdered coke introduced at the top of the crucible arch. 
 The steel produced in eight experimental heats contained from 0.12 
 to 0.35 % carbon. 
 
 The Italian process is similar to, but less perfect than, the 
 Catalan process. The hearth is smaller and shallower. The 
 tuyere is less inclined and enters the fire nearly in a line with 
 the opposite wall. The yield was only up to 40 or 45 %. 
 
 The Jones step process, as applied to iron ores provides for 
 metallizing (reducing) the oxides by subjecting them in a heated 
 condition, without fusion, to a reducing atmosphere. It is 
 claimed that a product consisting of 97 % pure iron can be secured 
 which is suitable preferably for briquetting and charging in an 
 open hearth furnace, or by melting in a cupola carbon can be 
 added for the manufacture of castings. In preparing the ore for 
 treatment, it is first crushed and passed Over a f inch screen. It is 
 mixed with coal and placed in the first of a pair of cylindrical 
 sheet iron furnaces arranged tandem. The charge may be 
 preheated to about 700 F. (370 C.) by an oil flame at which tem- 
 perature the reducing action begins and the preheating flame is 
 then shut off. The first stage consists largely of heating to about 
 
DIRECT PROCESSES 143 
 
 1500 F. (815 C.), with attendant volatilization of the hydro- 
 carbons in the coal and the partial reduction of the ore and the 
 formation of carbon monoxide. The pressure of gas causes 
 circulation and forces the gas into the second furnace where a 
 reducing atmosphere is established for another fresh charge. 
 When the action in the first tube is complete, as determined by a 
 time limit, this furnace is cut off, the charge dumped and quenched, 
 the same as coke, and jigged to separate the coke from the metal- 
 lic particles. The metallized ore is then crushed in rolls, magnet- 
 ically separated, and formed into briquettes, either by pressure 
 or with a tar binder. The two furnaces are thus alternately 
 dumped and charged (Iron Age, 12/14/11). 
 
 In Francis Knowle's process clean ore in lumps was heated 
 in retorts through which various reducing gases were passed. 
 
 H. Larkin's process employed magnetite which was crushed 
 and passed through a magnetic separator. The concentrates 
 were molded into bricks with carbonaceous matter, which 
 were then placed in retorts of D-section, externally heated with 
 gas. After exposure to a red heat for 24 hours, the iron was ob- 
 tained as a powder. 
 
 In the Lash- Johnson process ore and carbonaceous matter 
 are ground together to a fine powder, and mixed with a binding 
 material such as sodium silicate or tar. The resultant material, 
 after drying and coking, is spread on the hearth of a reverbera- 
 tory furnace. The surface is protected with a mixture of two- 
 thirds glass and one-third carbon, and the slag, fairly rich in 
 oxide, which is tapped off, is claimed to carry much of the phos- 
 phorus with it. 
 
 The Laureau process aims to deoxidize iron ore with natural 
 gas, and to prevent the deposition of carbon which occurs when 
 fuel is passed directly through hot ore. To prevent this, before 
 admitting the gas to the ore column, it is mixed with enough air 
 to convert its carbon into carbonic oxide, and the mixture is 
 heated to the temperature at which carbon tends to deposit. 
 But when the carbon is now set free, instead of depositing as such, 
 it unites with the oxygen present, and we have a mixture of 
 hydrogen and carbon monoxide (Howe). 
 
 In the Leckie process briquettes composed of coal or peat 
 were heated and deoxidized in chambers connecting with an 
 open hearth furnace containing a bath of pig iron into which 
 they were then transferred. 
 
 Liebermeister proposed to produce steel directly in a blast 
 furnace by interrupting the carburization at the proper moment. 
 
 In Samuel Lucas* earliest process ore was deoxidized with 
 carbonaceous matter in a furnace similar to that used for cementa- 
 tion. The sponge obtained was melted in crucibles. A later 
 method was to heat bars of wrought iron in alternate layers with 
 ore, charcoal, and oxide of manganese in the same type of furnace. 
 
 Matthiessen's process was not a commercial proposition 
 but simply designed to obtain chemically pure iron. It consisted 
 in fusing together pure ferrous sulphate and sodium sulphate, 
 washing the oxide obtained, and reducing it by heating in a 
 
144 DIRECT PROCESSES 
 
 stream of hydrogen, the resulting sponge being compressed in the 
 cold, or melted in lime crucibles. 
 
 David Mushet's process was about the same as the first one 
 of Lucas. 
 
 In the native forge or bloomary process (used in India and 
 the East) ore and charcoal are heated in a small clay furnace 
 with either natural or forced draft. From 20 to 120 Ibs. of iron 
 are produced from a charge. With natural draft about 20 tuy- 
 eres are used, and with forced draft there are 3 tuyeres. The 
 bloom is reheated and hammered to free it from slag. Both soft 
 and steely iron can be produced according to the charge. 
 
 In the Neville process ore and carbonaceous matter are charged 
 into the upper of two sets of chambers through which the gases 
 from the furnace pass and effect a partial reduction. The charge 
 is then dropped into the lower set of chambers, and thence into 
 the hearth of the furnace where it is balled. 
 
 W. E. Newton's process consisted in piling together layers 
 of ore, charcoal, etc., and flux which were heated in a suitable 
 vessel at a white heat for about 48 hours. The reduced iron 
 was melted in a crucible or treated in a puddling furnace. 
 
 The Nyhammer continuous high bloomary consists of a shaft 
 1 6 feet high and 18" wide, from the bottom of which covered 
 flues lead to closed charcoal hearths. Ore and charcoal are 
 charged in the hearth continuously, and through this the gases 
 from the charcoal hearths pass to heat the charge. The propor- 
 tion of ore to charcoal charged in the shaft is regulated so that the 
 temperature and reducing conditions in the shaft may be such as 
 to deoxidize the ore and heat the resulting sponge strongly, but not 
 to carburize or to soften it. The hot but not sticky spongy iron, 
 together with the residual charcoal, is raked from the bottom of 
 the shaft into one of the charcoal hearths, through one of the 
 flues already described. In this hearth the spongy iron is heated 
 to the welding point and balled, fresh lots of sponge apparenty be- 
 ing raked in as fast as the iron, balling, sinks, till enough for a bloom 
 has reached the hearth, when raking ceases or is diverted to 
 another hearth. The melted slag is tapped from the hearth, the 
 iron worked into a bloom, drawn and hammered (Howe). 
 
 The Osmund process employed a rectangular furnace (Osmund 
 furnace) about 8 feet high, and provided with one tuyere, and a 
 tapping hole for running off the slag. It was built of masonry, 
 which was packed around with earth held in place by a timber 
 casing. Calcined phosphoric bog or lake ores were smelted with 
 charcoal much as in the Catalan process, and the bloom (osmund) 
 was extracted by removing the front of the furnace. The loss 
 was about 33 to 50%. 
 
 The Otto process consists in reducing ore by gas under high 
 pressure in an externally heated horizontal retort, the gas 
 for reduction being subsequently used for heating the retort. 
 
 In Ponsard's process, which resembled Siemen's earlier 
 process, several fireclay retorts, 8" in diameter and 40" high, 
 were placed in a reverberatory furnace, their mouths being 
 fitted to openings in the roof, their lower parts open or perforated 
 
DIRECT PROCESSES 145 
 
 and resting upon the hearth which had gutters leading to a 
 central sump. In the retorts is charged ore with flux and about 
 12 % of carbon for deoxidation and carburization. The reduced 
 ore, melting, runs through the holes in the bottoms of the retorts 
 and collects in the sump (Howe). 
 
 Ramdohr's process consisted essentially in dropping fine 
 ore through a furnace of special construction, reduction being 
 effected by carbonic oxide. 
 
 In Jacob Reese's process ores were melted in a cupola, and 
 petroleum was blown through them. He expected the phos- 
 phorus to be given off as phosphoreted hydrogen. 
 
 In the Rinton process a furnace was employed resembling 
 an ordinary puddling furnace, with a vertical fire-brick retort 
 or chamber at one end, surrounded externally by the flues 
 from the furnace by which it was heated. Broken ore and 
 coal, in the proportion of i to 3, are charged in the retort, and 
 when the ore is sufficiently reduced the spongy iron is discharged 
 upon the hearth of the furnace and balled. 
 
 In G. Roger's process the iron ore mixed with coal is heated 
 and reduced in a rotating cylinder, externally heated, and situated 
 above a puddling furnace into which the resulting sponge is 
 dropped and balled. 
 
 The Rudolphs-Landin process consists in making briquettes of 
 fine ore, carbonaceous material, and flux as required, which are 
 dried, and the iron reduced while being passed through a long 
 furnace. The reduced briquettes are dropped into a bath of 
 molten metal covered with slag contained in a reverberatory fur- 
 nace, and portions of the bath are transferred from time to time 
 to an open hearth furnace and finished. 
 
 In the Sarnstrom process, a modification of the Osmund or the 
 Catalan process, the furnace consists of a vertical reduction shaft 
 connected with a number of hearths by small passages which can 
 be closed by dampers which are provided with small holes so the 
 gases from the hearths may pass through the shaft. Ore and 
 charcoal are charged at the top of the shaft, and during its des- 
 cent the ore is reduced and the iron sponge produced is worked 
 and balled in the hearths. 
 
 In A. Sattman and A. Homatsch's process ore is heated (cal- 
 cined if necessary) by the combustion of gas in a special type of 
 shaft furnace; reduction is effected by passing reducing gas alone 
 through the charge, the resulting sponge being melted in a 
 chamber at the bottom of the shaft, and connecting with a 
 closed chamber in which solid fuel .is burned. The fluid iron, 
 somewhat carburized, may be run directly into an open hearth 
 furnace and finished, or partial removal of the carbon may be 
 effected by hot oxidizing gases acting on the metal as it runs 
 from the melting chamber to a receiving chamber. The process is 
 intended to be worked either intermittently or continuously. 
 
 In the Schmidhammer process, apparently following out the 
 
 idea of the Nyhammer furnace, a special form of continuous 
 
 stiickofen was proposed. The shaft is charged continuously with 
 
 ore and enough charcoal for deoxidation; the ore is deoxidized 
 
 10 
 
146 DIRECT PROCESSES 
 
 during the descent; the temperature is raised to the welding point 
 by hot blast and hot water gas blown through the tuyeres; the 
 spongy iron is balled through working openings; and the balls are 
 drawn from a forcrhearth on lifting the door. The distinctive 
 features are substitution of hot gas and air for part of the more 
 costly charcoal; the fore-hearth and the door which permit of 
 formMg and drawing the balls without allowing the superincum- 
 bent charge to slide down as in Husgafvel's furnace (Howe). 
 
 C. W. Siemens' process: In one of his early direct processes 
 two cast-iron retorts or hoppers, with fire-clay ends, were sus- 
 pended above the hearth of an open hearth furnace. Around 
 each hopper is a space heated by a regulated supply of flame from 
 the open hearth furnace: within is a wrought-iron pipe supply- 
 ing producer gas for deoxidizing the ore. About 28 pounds of 
 charcoal is charged through each hopper, and on this sufficient ore 
 to fill the hopper completely. Producer gas is then injected 
 through the pipes in the center of the hoppers, and deoxidizes the 
 ore which has meanwhile been raised to redness by the heat con- 
 ducted through the walls of the hoppers. About half a ton of pig 
 iron is charged on the open hearth; melting, it dissolves the lower 
 end of the columns of more or less completely deoxidized iron, 
 with a rapidity which is only limited by the time needed to deoxi- 
 dize the ore in the hopper. Sufficient sponge having been thus 
 melted off in three or four hours, charging ceases, the remaining 
 ore in the hopper sinks, a clay-coated cast-iron cover suspended 
 by strong wire descending with the ore column, so that the flame 
 may not enter the empty hoppers. On this cover is placed the 
 charcoal and ore of the subsequent charge, eventually lowered by 
 cutting the wire. The charge already melted is brought to the 
 right degree of carburization, and, after an addition of spiegel- 
 eisen, is tapped (Howe). 
 
 In the later process (Siemens' precipitation process) fine ore 
 was reduced by coal, with which it was mixed and heated in a 
 rotating furnace, the coal precipitating metallic iron from the 
 molten ore. The resulting metal was balled as in puddling, 
 squeezed to expel slag, and either used as material for the open 
 hearth process, or worked into merchantable wrought iron. The 
 furnace was regenerative and gas fired (Howe). 
 
 The cascade furnace, used at one time by Siemens, instead of a 
 rotator, had two hearths at different levels. A lake of fused ore 
 was formed on the upper hearth, and, by piercing the intervening 
 bank of unmelted ore, was run at intervals upon the lower hearth, 
 upon which meanwhile a layer of equal parts of powdered anthra- 
 cite or coke and ore had been spread. On stirring, the mass 
 foamed and became pasty; in from 40 to 50 minutes the iron, 
 precipitated by the carbon, was balled, to be melted in the open 
 hearth or squeezed (Howe). 
 
 In Frederick Siemens' process ore, coal, and fluxes are charged 
 continuously through a slit at the end of a regenerative gas fur- 
 nace, which is rectangular in plan, with the entrance and exit 
 ports at the same end, the opposite end being strongly inclined. 
 The heat is so high that the ore melts immediately on entering 
 
DIRECT PROCESSES 147 
 
 the furnace, and so coats over and protects the coal from the ac- 
 tion of the flame of the furnace. The melting ore trickles down 
 the incline, its iron being reduced by the coal, partly during its 
 descent, partly after reaching the bath at the bottom of the 
 incline. Basic additions are made to the molten slag to permit 
 dephosphorization and the reduction of the iron. The slag runs 
 out continuously; the metal is tapped from time to time (Howe). 
 
 In Snelus* process the ore, heated in a special form of furnace, 
 was to be reduced by carbonic oxide or hydrogen. 
 
 O. Stromborg's process employs an open hearth furnace pro- 
 vided at the top with special reservoirs from which tubes extend 
 down below the surface of the bath on the hearth through which 
 ore and carbon, separately, are forced under air pressure. The 
 furnace being provided with molten steel, carbon is introduced, 
 and, after it has been taken up by the bath, ore is added to be 
 reduced by the carbon. Heating may be effected by producer 
 gas as in ordinary open hearth practice, but principally by blowing 
 air through one of the feed pipes. A limy slag is employed which 
 can be tapped off as necessary. 
 
 The stiickofen or old high bloomary (also called salamander 
 furnace, wolf furnace, wolf oven, wulf 's oven, and stuck oven) 
 was a shaft furnace 10 to 16 feet high, either round or rectangular 
 in section, and provided with one tuyere, somewhat over a foot 
 above the hearth, and a drawing hole for the blooms. It may be 
 considered as approaching the present blast furnace, and fre- 
 quently cast iron was produced. The fuel was charcoal. The 
 wolf oven was somewhat lower, and between it and the stiickofen 
 German metallurgists (Percy) place a furnace of intermediate 
 height called blaseofen and bauernofen (osmund furnace, in 
 Sweden). The product of the stuctofen may contain a certain 
 amount of highly carburized iron, and when the bloom is reheated 
 and most of this cast iron runs out, the remainder, which is more 
 infusible (wrought iron), is called a blume (Overman). 
 
 Swedish Metallic Sponge. This appears to be manufactured 
 by a process similar to Chenot's. It is obtained by reducing 
 compressed briquettes of ore by carbon monoxide at a tempera- 
 ture slightly below the melting point of iron. The ore used is 
 a magnetite as pure as possible. The sponge produced is very 
 light, in color varies from blue to black, has no metallic luster, 
 and is not very pleasing in appearance. The analysis of a 
 sample showed metallic iron slightly over 96% (Rev. Met.). 
 
 The Tourangin process is a modification of Chenot's direct 
 or internal method of heating. The furnace employed was 
 about 20 feet high, and cost less than Chenot's, but the principle 
 was the same. The sponge produced was drawn at the bottom, 
 covered with ashes, or kept in special water-jacketed legs at 
 each side of the furnace until cool, and subsequently worked up 
 in a charcoal hearth, etc. (Percy). 
 
 In the Trosca process ore was reduced by contact with carbo- 
 naceous matter in externally heated vertical retorts; the resulting 
 sponge was removed in an air-tight buggy (Howe). 
 
 In the Twynam process briquettes of ore and carbonaceous 
 
148 DIRECT RECOVERY DODECAHEDRAL 
 
 matter were thrown into the bath of metal in a basic open 
 hearth furnace. 
 
 Westman's process resembles Cooper's except that common 
 producer gas is used, and that the gas passes through the regenera- 
 tor while on its way from the gas producer to the deoxidizing 
 furnace (Howe). 
 
 In the Wilson process coarsely pulverized ore with 20% 
 of charcoal or coke dust is heated to 800 to 1000 F. (427 to 
 538 C.) for 24 hours in vertical retorts at the end of a puddling 
 furnace by whose waste heat they are heated externally. The 
 partially deoxidized ore is then dropped into a second hearth of 
 the puddling furnace, and after 20 minutes more is pushed into 
 the hearth proper where it is balled (Howe). 
 
 The Yates process appears to be identical in principle with 
 Chenot's indirect heating process, reduction of the ore being 
 effected by heating in contact with carbonaceous matter in 
 vertical retorts in sections, one above the other, connected by 
 socket joints, and heated externally with producer gas. The 
 sponges produced are balled in a puddling furnace. 
 
 Direct Recovery Process. See page 96. 
 
 Direct Stress. See page 332. 
 
 Dirt Inclusion. See page 57. 
 
 Dirt Pocket. See page 311. 
 
 Dirty Gas. See page 33. 
 
 Discard. In rolling or forging, particularly ingots, the portion cut 
 off and rejected to insure sound material. The discard from the 
 top, whether from the ingot, the bloom or billet, or the finished 
 section, containing the pipe and the segregated portion, is called 
 specifically the top discard, and the piece next to it, the top cut ; 
 the discard at the bottom, the bottom discard, and the piece next 
 to it, the bottom cut. Both discards are also referred to as 
 crops or crop ends. 
 
 Discontinuous Combustion. See page 202. 
 
 Discontinuous Curve. See Curve. 
 
 Discrystallization. Amorphizing: seepage 282. 
 
 Dishing. See Cold- Working. 
 
 Disk Radio -balance. See page 207. 
 
 Dissociation ; Point ; Theory. See page 89. 
 
 Dissolved Carbon. See page 275. 
 
 Distillation. See page 202. 
 
 Distillation Process. See page 385. 
 
 Distinct Cleavage. See page 124. 
 
 Distortion. See page 334. 
 
 Distribution of Carbon. See page 213. 
 
 Distribution, Coefficient of. See Coefficient of Distribution. 
 
 Distributor. For ore: see page 32. 
 
 Divalent. See page 86. 
 
 Divariant System. See page 327. 
 
 Division. See page 81. 
 
 Divorcing ; Divorcing Annealing. See page 274. 
 
 Dode Process. See page 370. 
 
 Dodecahedral Cleavage. See page 124. 
 
DODECAHEDRAL IRON ORE DRAW PLATE 149 
 
 Dodecahedral Iron Ore. See page 244. 
 
 Dog Collar. See page 315. 
 
 Dolite. See page 399. 
 
 Dolly. A heavy iron bar, suspended at about the middle, used to 
 strike a heavy blow by swinging it against the given object 
 in the same manner as with an ancient battering ram; also called 
 tup or monkey. 
 
 Dolomite. See pages 175 and 397. 
 
 Dominant Element ; Metal. In an alloy: see page 4. 
 
 Dormer Mill. See page 434. 
 
 Doubles. Of sheets: see page 430. 
 
 Double-acting Hammer. See page 196. 
 
 Double Annealing. See page 232. 
 
 Double-burned Dolomite. See page 397. 
 
 Double Furnace ; Double-double Furnace. See page 376. 
 
 Double Gross Ton (obs.). See Ton. 
 
 Double Hardening. See page 228. 
 
 Double-level Furnace. See page 312. 
 
 Double -melting Process. See page 75. 
 
 Double Mill. See page 430. 
 
 Double Pouring. See page 57. 
 
 Double-refined Iron. See page 378. 
 
 Double-rolled Iron. See page 378. 
 
 Double Shear. See page 337. 
 
 Double Shear Heat. See page 71. 
 
 Double Shear Steel. See Shear Steel. 
 
 Double Shrink. See page 296. 
 
 Double Skip. See page 33. 
 
 Double Steel; Doubler ; Doubling Shear. Of sheets: see page 430. 
 
 Doubly Converted Bars. See page 71. 
 
 Doubly Oblique System. Of crystallization: see page 120. 
 
 Doubly Refined Iron. See page 378. 
 
 Dowlais Mill. See page 417. 
 
 Down Draft Producer. See Producer. 
 
 Downcomer. See page 33. 
 
 Dowson Gas. See Producer. 
 
 Dozzle. See page 59. 
 
 Draft. (i) In molding: see page 296; (2) in rolling: see page 407. 
 
 Draft Fluid Compression. See page 64. 
 
 Drag. See page 297. 
 
 Draper's Law. See page 208. 
 
 Draught. See Draft. 
 
 Draw. (i) In the crucible process: see page 115; (2) in heat 
 treatment: see pages 230 and 2325^(3) in molding: seepage 296; 
 (4) of wire: see page 507. 
 
 Draw Bench. See page 508. 
 
 Draw Bottom. See page 17. 
 
 Draw Down. To reduce the section of a piece of metal by mechan- 
 ical means, such as hammering, rolling, or drawing. 
 
 Draw Hole. (i) In castings: see page 53; (2) for wire: see page 
 507- 
 
 Draw Plate. See page 507. 
 
1 50 DRAW TEMPERING DUCTILIMETER 
 
 Draw Tempering. See pages 230 and 232. 
 
 Drawing Back. See pages 230 and 232. 
 
 Dressing. (i) Of castings: see page 58; (2) of ores, preparing by 
 
 crushing, washing, etc. (but not roasting) ; (3) of metallic pieces, 
 
 machining; (4) of rolls, turning down in a lathe after they have 
 
 become worn. 
 
 Drier. Of a paint: see page 365. 
 Drift Test. See page 477. 
 Drill Temper. See Temper. 
 
 Driving-in Method. To determine hardness: see page 478. 
 Drop (obs.) See Slag. 
 Drop of the Bath. See page 376. 
 Drop of the Beam. See page 469. 
 Drop Bottom. See page 182. 
 Drop of the Flame. See page 20. 
 Drop Forging. See Forging. 
 Drop Hammer. See page 197. 
 Drop Stamping (Eng.). Drop forging. 
 Drop Test ; Drop Weight Test. See page 481. 
 Dross. The sullage, scurf, oxide, or other impurities which are 
 
 skinned off the top of molten metals, or which accumulate in the 
 
 sinkhead or riser of a casting. 
 
 Drummer (Eng.). A smith's hammerman (Homer). r v 
 
 Druse; Drusy Cavity. See page 125. 
 Dry ; Dryness. (i) Of pig iron, low in silicon; (2) of slags, infusible; 
 
 (3) of steel which is red-short or tender: see Brittleness. 
 Dry Analysis. See page 82. 
 Dry Blacking. See page 298. 
 Dry Blast. See page 29. 
 Dry Bottom. See pages 253 and 377. 
 Dry Brush. See page 298. 
 Dry Cleaning. Of gas: see page 33. 
 Dry Coal. See Coal. 
 Dry Drawing. Of wire : see page 508. 
 Dry Dust Catcher. See page 33. 
 Dry Finish. Of sheets: see page 433. 
 Dry Fusion. See page 201. 
 Dry Galvanizing. See page 371. 
 Dry House.^-In wire practice: see page 507. 
 Dry Iron. See page 343. 
 Dry Method of Analysis. See page 82. 
 Dry Ore (Eng.). See page 243. 
 Dry Process. See page 82. 
 Dry Puddling. See page 374. 
 Dry Sand ; Dry Sand Molding. See page 296. 
 Dry Slag. See Slag. 
 Drying. (i) Of molds: see page 298; (2) same as coming to nature: 
 
 see page 376. 
 
 Drying Oven ; Stove. See page 298. 
 Du Puy Process. See page 140. 
 Dualistic Theory. See page 89. 
 Ductilimeter (rare). See page 483. 
 
DUCTILITY DYNAMOMETER 151 
 
 Ductility. (i) General: see page 331 ; (2) formulae for: see page 338. 
 
 Ductility test. See pages 481 and 483. 
 
 Diidelingen Process. See Recarburization. 
 
 Dull Fracture. See page 178. 
 
 Dull Iron ; Metal. See page 343. 
 
 Dulong's Law. See page 203. 
 
 Dulong & Petit's Law. See page 85. 
 
 Dummy Tuyere. See page 17. 
 
 Dump. To discharge by gravity, as the contents of a cupola. 
 
 Duo Mill. See page 408. 
 
 Duplex Constituent. Eutectic: see page 266. 
 
 Duplex Process. See page 317. 
 
 Durr (Eng.). Jar or shock. 
 
 Dust Catcher ; Chamber. (i) In connection with a blast furnace: 
 
 see page 33; (2) this term is rarely used for the cinder pocket of 
 
 an open hearth furnace. 
 Dust Coke. See page 97. 
 Dust Plate (obs.). A vertical iron plate supporting the slag runner 
 
 of a blast furnace (Raymond). 
 Dusting. Of sheets: see page 430. 
 Dwight and Lloyd Process. See page 45. 
 Dyad. See page 86. 
 Dyer Process. See page 317. 
 Dynamic Deformation. See page 333. 
 Dynamic Hardness. See page 331. 
 
 Dynamic Indentation. To determine hardness: see page 478. 
 Dynamic Load. See page 333. 
 Dynamic Metamorphism. See page 122. 
 Dynamic Methods. Of hardening: see page 279. 
 Dynamic Resistance ; Strains ; Strength ; Stress. See pages 330 and 
 
 333- 
 
 Dynamic Test. See pages 468 and 481. 
 Dynamic Theory of Heat. See page 199. 
 Dynamometer. See page 483. 
 
E 
 
 Er. Chemical symbol for erbium: see page 84. 
 
 Eu. Chemical symbol for europium: see page 84. 
 
 E.B.B. Wire. See page 509. 
 
 E.S.C. (Brit.)- The Engineering Standards Committee (q.v.). 
 
 Eames Process. See page 138. 
 
 Ease, State of. See page 332. 
 
 East Coast Hematite. See page 344. 
 
 Eaton Process. (i) In cementation: see page 68; (2) in purifica- 
 tion: see page 385. 
 
 Ebullition. See page 202. 
 
 Eccentric Converter. See page 17. 
 
 Edge Steel. In a casting, the metal solidifying first on the outside, 
 and which on etching sometimes presents a different appearance 
 from the central portion which is then called core steel. 
 
 Edging Pass. See page 408. 
 
 Edison Gage. See page 187. 
 
 Edwards and Carpenter's Theory. Of hardening: see page 381. 
 
 Edwards Flying Shears. See page 413. 
 
 Efficiency of Corrosion. See page 108. 
 
 Effloresce; Efflorescence. See Water. 
 
 Egg Coke. See page 97. 
 
 Ehrenwerth Process. See page 141. 
 
 Ehrenwerth and Prochaska Process. See page 317. 
 
 Eifel Walloon Process. See page 80. 
 
 Eisen-Portland. See Slag Cement. 
 
 Elastic After-working. See page 333. 
 
 Elastic Break- down. See page 333. 
 
 Elastic Compressive Strength. See page 336. 
 
 Elastic Deformation. See page 330. 
 
 Elastic Limit. (i) General: see pages 330 and 469; (2) by dividers: 
 see page 470; (3) by drop of the beam: see page 470; (4) by exten- 
 someter: see page 470. 
 
 Elastic Limit Strength. See page 330. 
 
 Elastic Ratio. See page 335. 
 
 Elastic Resilience ; Strain ; Strength. See pages 330 and 331. 
 
 Elasticity. (i) General: see page 330; (2) coefficient of: see page 
 334; (3) modulus of: see page 334. 
 
 Eldred Process. See page 24. 
 
 Electric Arc Furnace. See page 153. 
 
 Electric Arc-resistance Furnace. See page 153. 
 
 Electric Blast. See page 503. 
 
 Electric Casting. See page 65. 
 
 Electric Furnace Process. See page 153. 
 
 Electric Furnaces, Types of. See page 153. 
 
 Electric Hardening. See page 230. 
 
 Electric Processes. For cementing: see page 70. 
 
 Electric Processes. Electricity, in the commercial manufacture of 
 
 152 
 
ELECTRIC PROCESSES 153 
 
 iron and steel, is used almost exclusively as a source of the heat 
 necessary to cause the various reactions to take place, and not for 
 any direct chemical action, or only to a limited and practically 
 negligible extent; the more correct, and therefore preferable, 
 designation is electro-thermal or electro -thermic process or, re- 
 ferring to the type of furnace employed, electric furnace process 
 (also termed electro -metallurgical process, and the product, elec- 
 tric steel). Electrolysis of suitable solutions, which depends on a 
 direct chemical reaction, has recently been developed to a point 
 where production of nearly pure iron is on a commercial but 
 comparatively limited scale (see Electrolytic Iron, page 165). 
 
 Electro-thermic processes may be classified according to the 
 following types of furnace, based on the manner in which the 
 heating is effected. 
 
 1. Induction furnace (induction heating) : The furnace usu- 
 ally consists of an annular trough (the furnace proper), the con- 
 tained metal constituting part or all of the secondary circuit of a 
 transformer (an alternating current must be employed), the pri- 
 mary circuit of which is arranged as usual. The type where the 
 bath forms the entire secondary winding is called a simple induc- 
 tion furnace ; where the bath forms only a part of the secondary 
 circuit, a copper winding being added to assist in the heating, it 
 is a combination induction furnace. 
 
 2. Resistance furnace (resistance heating): The charge or 
 bath of metal forms part of the regular circuit, and the resist- 
 ance it offers to the passage of the current yields the required 
 temperature. 
 
 3. Surf ace resistance furnace : The electrodes do not suffice for 
 the passage of the current. To heat up the furnace it is necessary 
 to connect them by means of some kind of conducting material, 
 such as a bed composed of pieces of carbon. These conductors 
 are then brought to a state of extreme incandescence, and form a 
 melting hearth upon which the materials to be treated are placed. 
 The materials themselves afterward, being traversed throughout 
 their extent by the current, serve as a conductor between the 
 electrodes (Keller). 
 
 Arc furnace, radiation furnace, or arc radiation furnace (arc 
 heating, radiation heating) : The requisite temperature is 
 obtained by radiation from an arc (radiating arc) formed between 
 two electrodes, or between two or more electrodes and the charge. 
 In the latter case the current may pass from one electrode into the 
 bath, then out again to another electrode in series with the first, 
 or through the bottom of the furnace (which in this case forms an 
 electrode) ; the direction being constantly reversed if an alternat- 
 ing current is employed. By either method a certain amount of 
 resistance heating occurs (indirect resistance heating), and this 
 combination is called an arc-resistance, resistance -arc, or 
 combined arc and resistance furnace. 
 
 The advantages of electric heating as compared with that 
 obtained from the combustion of fuel are, in general: 
 (a) A higher temperature available. 
 
154 ELECTRIC PROCESSES 
 
 (b) The possibility for greater purification, both because the 
 
 high temperature available permits a slag high in lime 
 which otherwise would be too infusible, and also because 
 reducing conditions can be maintained (particularly at 
 the end of the process) whereby reduction and consequent 
 elimination of oxides and dissolved oxygen can be 
 secured. 
 
 (c) More complete exclusion of air or gases (except in the 
 
 case of the crucible process). 
 
 (d) Carbon is required only for reduction (also for recar- 
 burization, if desired) , including what is added to the slag 
 for this purpose, hence a smaller amount of impurities is 
 introduced than with ordinary fuel. 
 
 The usual disadvantage is: 
 
 (e\ That the cost is generally higher, except where power is 
 extremely cheap and fuel dear (as in Norway), so it is 
 usually available only for the finer grades of steel (e.g., to 
 replace that made by the crucible process), or when used 
 simply for final purification. 
 
 The furnaces are nearly always basic lined, so that purification 
 with lime can be effected, but they can also be acid lined if desired. 
 
 Allevard process: Very little has been published about this 
 process. It is stated that an electrode furnace is employed in 
 which various grades of steel are made from either pig and ore or 
 pig and scrap. 
 
 The Anderson furnace for refining or making steel appears 
 to be very similar to a.Heroult furnace, with the addition of 
 electro-magnets placed underneath the furnace in line with the 
 electrodes, from which arrangement benefits are claimed. A 
 type for smelting ores is similar to the Keller furnace, designed 
 for that purpose. 
 
 The Bailey resistance furnace is used-simply as a heating furnace 
 for forging or heat treating purposes. The resistance material is 
 essentially crushed coke connected with graphite electrodes and 
 protected by a lining of magnesite. 
 
 The Borchers furnace, which is somewhat similar to the above, 
 being used only for heating purposes, employs a carbon rod of 
 relatively small cross-section, called a resistor, which is heated 
 by the passage of the current, and about which the charge is 
 placed. 
 
 The Burke furnace is of the arc type, operates at perferably two 
 phase, each circuit entirely distinct from the other (Vom Baur). 
 
 In the Chapelet furnace, of the arc type, the current flows into 
 the bath from a hanging carbon electrode, much as in the Girod 
 furnace. From the bath it goes through a horizontal channel to 
 a hanging cast iron electrode that touches the channel. This 
 constitutes the peculiarity of the furnace. It is not apparent 
 that this offers any advantage over the Girod arrangement (Vom 
 Baur). 
 
 The Colby furnace is very similar to the Kjellin, differing 
 principally in the use of a copper tube, through which water 
 
ELECTRIC PROCESSES 1 5 5 
 
 circulates, for the primary coil. It was patented by E. A. Colby, 
 and the rights for these two furnaces in this country have bee'n 
 consolidated under one management; it is then called a Kjellin- 
 Colby furnace. 
 
 M. R. Conley's process is somewhat similar to Stassano's, 
 as reduction and purification are effected in the same chamber. 
 The furnace employed has somewhat the shape of a blast furnace : 
 the walls converge at about the middle, below which is the hearth 
 where the final reduction and melting take place; the charge is 
 introduced at the top, and the molten products are tapped out 
 through a hole at the bottom. The furnace is of the resistance 
 type: the current is brought into contact with the charge by 
 means of two graphite electrode rings built into the wall, one of 
 which is at the narrowest point of the furnace and the other a 
 short distance above. It was designed to produce either cast 
 iron or steel. 
 
 The Crafts furnace is a steel furnace of the induction type 
 in which the transformer cores are horizontal instead of vertical. 
 These cores are around heating channels leading up to the bath 
 above, much like the flues in an open hearth furnace. The 
 channels are always full of molten metal. The bath can be 
 worked as in an open hearth furnace (Iron Age, Sept. 18, 1913). 
 
 In the Ferranti process, patented in 1885, the first induction 
 furnace was employed, which, however, did not prove a com- 
 mercial success. It consisted of a laminated iron core wound 
 with fine wire, constituting the primary circuit, and around 
 this an annular refractoryitrough in which the molten metal formed 
 the secondary circuit. 
 
 The Frick furnace is of the induction type, and is very similar 
 to the Kjellin, the principal difference being that in the former 
 the primary windings are placed above and below the annular 
 hearth instead of within it. Heating is produced in exactly 
 the same way. Another difference is that the Frick furnace 
 has a single cover which can be rotated, so that, by having 
 one opening, the whole of the ring-shaped hearth can be in- 
 spected. Also a skimmer introduced through the hole during 
 rotation would serve to bring the slag to the spout very easily. 
 
 The Galbraith furnace was designed to extract iron from 
 fine ores without previous briquetting. The iron sand is mixed 
 with fine carbon and is led downward in a zigzag manner in a 
 furnace constructed entirely of graphite over twelve roasting 
 bars also made of graphite. The entire furnace is closed. On 
 their way through the furnace, the ores mixed with fine carbon 
 are reduced and, to assist in this, carbureted hydrogen is also 
 introduced into the lower portion of the furnace. The iron col- 
 lects at the bottom in a liquid state. 
 
 Gin furnace : One form is of the resistance type. In this the 
 metal is contained in a long, narrow, shallow trough to obtain 
 sufficient resistance and which, for convenience, is doubled upon 
 itself. Connection with the current is made at the ends of the 
 trough by two water-cooled metal electrodes plunged in the 
 molten metal. A later form is of the induction type: the metal 
 
156 
 
 ELECTRIC PROCESSES 
 
 circulates in a number of troughs connected together by channels; 
 the bottoms of the troughs are inclined. The furnace is tilting, 
 and has a rectangular shape. 
 
 The Girod furnace resembles a small tilting open hearth 
 furnace. The hearth consists of a circular or oblong cavity 
 in which the metal when molten reaches a height of from 10 
 to ii inches. One or more electrodes (depending upon the 
 size of the furnace) in parallel are maintained above the bath, 
 and soft steel pieces, embedded in the hearth of the furnace, 
 and in direct contact with the molten metal, form the negative 
 
 FIG. 16. Girod furnace. A, molten metal. B, upper electrode. 
 C, lower electrode (Eng. and Min. Jour.). 
 
 electrode. The current, entering by the way of the upper elec- 
 trode, forms an arc between itself and the bath, traverses the 
 bath, and passes out through the lower pole pieces, the upper 
 parts of the lower pole pieces, which are in direct contact with 
 the metallic bath become molten at their extreme ends; the 
 lower ends are water-cooled. This furnace is of the arc type. 
 Giron also manufactured ferro-alloys in a resistance furnace in 
 which the resistance consisted of a layer of graphite in the walls; 
 this type was also used for a crucible furnace. 
 
 The Grondal-KjelHn furnace, or Grondal furnace, is a modi- 
 fication of the original Kjellin furnace, differing principally 
 
ELECTRIC PROCESSES 
 
 in the method of forming the primary circuit, and in means 
 provided for tilting. 
 
 The Gronwall furnace of the induction type was devised with 
 the object of increasing the resistance of the bath and so improve 
 the power factor by greatly elongating the ordinary channel of 
 
 FIG. 17. Gronwall furnace; vertical section. 
 
 the induction furnace. This result is largely secured, but with 
 considerable losses of heat by radiation (Vom Baur). 
 
 The Gronwall or Gronwall, Lindblad and Staalhane electric 
 shaft furnace is devised for the reduction of iron from its ore, and is 
 unlike any hitherto constructed, resembling most nearly an ordi- 
 nary blast furnace in which the tuyeres are replaced by electrodes, 
 
158 ELECTRIC PROCESSES 
 
 three in number. The height of the furnace above ground level is 
 about 25 feet. The melting chamber or crucible containing the 
 electrodes is about 7 feet high, and is of greater diameter than any 
 other part. The shaft is about 18 feet high, the lower end of 
 which for about 4 feet has the form of an inverted truncated 
 cone; the angle of this cone is for the purpose of directing the 
 charge into the crucible in such a manner that the electrodes, lin- 
 ing, and descending charge could not come into contact. The 
 melting chamber is made in the form of a crucible, and is covered 
 with an arched roof provided with openings for the reception of 
 the electrodes and for the descending charge. The roof and 
 walls of the crucible are lined with magnesite. For the purpose of 
 cooling the brick- work composing the lining of the roof of the melt- 
 ing chamber, and thereby increasing its life, three tuyeres are 
 introduced into the crucible-j-just above the melting zone 
 through which the comparatively cool tunnel-head gases are 
 forced against the lining of the roof into the free spaces. The 
 shaft is supported independently above the melting chamber by 
 an iron plate resting on six cast-iron pillars. The charge, con- 
 sisting of ore, coke (or charcoal), and limestone, is introduced at 
 the top by means of a bell and hopper, and the molten products 
 are tapped out through a hole at the bottom of the hearth. 
 
 The Halberger furnace is of the indirect resistance type for 
 crucible melting and is arranged so the resistance is furnished by 
 the walls of the crucibles themselves, which are made of the ordi- 
 nary carbon or graphite mixtures. Before using they are pre- 
 pared by a patented process which permits the current to pass 
 through the crucible walls only (Vom Baur). 
 
 The Harmet process was devised for the production of iron and 
 steel direct from the ore, and does not differ materially from vari- 
 ous others. The furnace consists of three superimposed fur- 
 naces connected together. The top one acts as a calciner, the 
 middle one as a blast furnace for the reduction, and the bottom 
 one, which is of the open hearth type, for the refining of the raw 
 product. Ore and flux are charged into the calciner, and are 
 heated by the combustion of the gases resulting from the reduc- 
 tion of the ore with fuel below. 
 
 The Helf enstein furnace is of the shaft type and was originally 
 used for the manufacture of calcium carbide and ferro-silicon, but 
 now also employed for making pig iron and steel. There may be 
 a number of shafts with a common hearth of conducting material. 
 The charge is introduced continuously at the top of the shafts 
 where the electrodes are located. 
 
 The HerSus furnace is a small laboratory furnace for heating 
 crucibles, combustion tubes, etc., consisting of a tube of porcelain 
 or other refractory material which is heated by a resistance coil of 
 platinum wire or strip wound about it, and protected from radia- 
 tion on the outside by a layer of heat insulating material. 
 
 The Hering furnace is based on the pinch phenomenon : When 
 a current passes through a conductor, the magnetism produced 
 in and about it has a crushing effect, as the surrounding magnetic 
 flux acts like stretched rubber bands. This crushing force is not 
 
ELECTRIC-PROCESSES 
 
 159 
 
 strong enough to be noticeable in solid conductors, but when they 
 are liquid, and the current is sufficiently large, it is clearly evident. 
 This is sometimes powerful enough to sever the conductor, and 
 generally occurs locally at the weak spot. If the conductor con- 
 sists of a column of molten metal confined in a hole in a refractory 
 material near the bottom of a crucible, and if the outer end is 
 sealed by the electrode and the inner end opens into the bath or 
 in the crucible, the pinching effect will force the liquid out through 
 the center of the open end. As this end is submerged the con- 
 ductor cannot pinch off, but instead liquid will be sucked in cir- 
 cumferentially, thus producing simultaneous outward and inward 
 flow of liquid through the hole (Hering, Trans. Am. Electrochem. 
 Soc., XXXV). 
 
 The Heroult furnace is tilting, and is very similar to the type 
 employed in the open hearth process except there are no ports 
 for the entrance and exit of gases. There are usually two elec- 
 
 FIG. 1 8. Heroult double arc furnace. (Eng. and Min. Jour.) 
 
 trodes which pass through the roof and whose height can be 
 regulated by suitable means. One of these is attached to the 
 negative pole and the other to the positive pole, and the current 
 passes between them through the bath with which they may be 
 in contact, but are generally separated by a small space over 
 which an arc is maintained. The furnace may be used for treat- 
 ing materials in the same manner as in the open hearth process, 
 but it has been found advantageous to work with blown metal 
 from a Bessemer converter, or nearly finished metal from an 
 open hearth furnace. The purification may be very complete 
 as a high-lime slag can be maintained. As a rule the first 
 slag, containing most of the phosphorus, is removed, and a 
 second slag, consisting of lime and fluorspar, is then formed. 
 Crushed coke is added to complete the removal of the oxygen in 
 the bath. A process devised by Ernest Humbert (Dr. He*roult's 
 metallurgist) consists in removing the phosphorus, not as usual as 
 phosphate but as phosphide. Use is made of an oxidizing basic 
 slag to combine with the phosphorus and form a phosphate, after 
 which a reducing material, usually crushed coke, is added, and 
 
160 ELECTRIC PROCESSES 
 
 floats on the slag, reducing the calcium phosphate to phosphide, 
 which cannot be taken up by the iron as phosphorus without first 
 being converted back to phosphate. In this way it is intended to 
 purify with a single slag, but so far, on tapping, a considerable 
 amount of phosphorus seems to pass back into the metal. 
 
 Heroult ore smelting furnace: The furnace consists of an 
 approximately vertical shaft at the top of which the coke for the 
 reduction is charged. On one side there is an inclined shaft by 
 which the ore is introduced into the main shaft and comes into 
 contact with the column of coke. The heat is supplied by the 
 resistance of the charge to the passage of the current. There are 
 two electrodes, both consisting of solid blocks of carbon, one of 
 which is situated near the top of the coke column, and the other 
 at the bottom of the hearth. The action is somewhat similar to 
 what takes place in a blast furnace, the molten pig and slag which 
 collect in the hearth being tapped out through suitable openings. 
 A modification consists of a single shaft with a tapping hole at the 
 bottom, charcoal being used for fuel. The two electrodes consist 
 of a carbon block in the hearth and a large carbon rod suspended 
 at the top of the shaft, much as in a Keller furnace. 
 
 Hiorth furnace: The leading feature of this furnace is that 
 it dispenses with the use of electrodes. A large electro-magnet, in 
 the form of a horseshoe, has across the two ends a perpendicular 
 rod, about which it can move readily. Around this rod is the 
 primary winding of fine wire. Through the open space, and sur- 
 rounding the top of the horseshoe, is a circular trough which con- 
 stitutes the furnace proper. When this is charged, a high tension 
 current is passed through the windings which induces a secondary 
 current in the trough and its contents. 
 
 The Irving or Moffat furnace consists of a crucible into which 
 three inclined electrodes project, where reduction is completed 
 with coke, surmounted by a stack, through which the charge 
 passes to the crucible, being there preheated and partially re- 
 duced by carbon monoxide. 
 
 Keller furnace (Keller-Leleux process) : The furnace formerly 
 employed was very similar to the H6roult type, the current pass- 
 ing from one electrode into the bath, and then out of it into an- 
 other electrode, both electrodes being above the bath. In one 
 form it consisted of two furnaces at different levels, one fixed and 
 one tilting. When working with pig and scrap, the materials 
 were melted and partially refined in the upper stationary furnace, 
 and then run into the lower tilting furnace where the process was 
 completed; with scrap alone the whole operation was conducted in 
 the tilting furnace. In the latest type adopted, which resembles 
 Girod's furnace, there is only one electrode at the top or, if 
 several electrodes are employed, they are all connected in parallel; 
 the other terminal is the bottom or hearth of the furnace. The 
 current, therefore, passes from the electrode at the top into the 
 bath and leaves the furnace at the bottom. In a recent patent, 
 which provides for a durable bottom, Keller places a bundle of 
 iron bars vertically in the furnace bottom, connecting them to a 
 conducting plate arranged below their bottom ends. Between 
 
ELECTRIC PROCESSES 
 
 161 
 
 these bars and around the bundle which they form, a refractory 
 material, preferably magnesia, is strongly rammed. The fur- 
 nace bottom consists, therefore, partly of vertical iron rods and 
 parly of magnesia, the latter also becoming a conductor at high 
 temperatures. 
 
 The Keller ore smelting furnace is practically the same in 
 principle and construction as the form originally' employed for 
 making steel, and is of the resistance type. There are two verti- 
 cal shafts connected at the bottom by a horizontal canal. The 
 charge, consisting of the proper proportion of ore, coke, and flux, 
 is charged at the top of both shafts, and reduction takes place 
 during its descent. One large carbon electrode is suspended in 
 each shaft, connected respectively to the negative and the posi- 
 tive terminals. The bottoms of the shafts are connected by a 
 copper rod on the outside and underneath, fastened to blocks of 
 carbon. A small well between the two shafts serves to collect the 
 molten materials. If there is any danger of chilling up, a third 
 electrode can be brought into action at this point to supply the 
 additional heat required. 
 
 The Kjellin furnace is of the induction type. The hearth or 
 crucible is in the form of an annular ring provided with covers, 
 
 PIG. 19. Kjellin induction furnace. AA, circular trough in 
 which steel is melted and treated. C, magnetic core. D, primary 
 coil. E, frame connecting ends of C. F, cover for melting chamber. 
 G, spout. (Eng. and Min. Jour.} 
 
 and the contained metal forms the secondary circuit of a trans- 
 former, the primary circuit of which consists of a coil of fine, in- 
 sulated copper wire with a laminated iron core. The winding is 
 placed on one leg only, the primary being next the core, and the 
 secondary outside of this. It is protected from radiated heat by 
 air spaces and a water jacket. The process has generally been 
 used for obtaining steel of any grade from dead soft to hard by a 
 suitable mixture o'f pure pig and scrap, with the proper additions 
 of ferro-silicon, etc.; little purification has been attempted. The 
 initial charge has been cold pig and scrap, but after it has been 
 operating, only a portion is tapped out each time. 
 
 The Lavol furnace was one of the earlier forms of resistance fur- 
 nace designed for refining spongy iron. The furnace, of cylindri- 
 11 
 
l62 
 
 ELECTRIC PROCESSES 
 
 cal shape, consisted of two compartments to be filled with molten 
 iron oxide to above the top of the separating wall. The current 
 passed through this between electrodes placed in the bottom of 
 the compartments. The spongy iron was to be refined while sink- 
 ing through this molten oxide. 
 
 The Ludlum furnace, used for producing cast steel, cast iron, 
 low phosphorus pig, and washed metal from steel scrap, is of the 
 arc type. It has an elliptical hearth in which are three electrodes 
 in line, which arrangement is claimed to give great uniformity. 
 
 The Nathusius furnace is of the arc type with additional 
 resistance, and represents a combination of the H6roult and the 
 Girod furnace, the current traveling between combinations of 
 electrodes above and below the bath, so that it also passes 
 through the bath (Vom Baur). 
 
 FIG. 20. Rochling-Rodenhauser furnace. 
 (Eng. and Min. Jour.) 
 
 The Noble furnace is very similar to the Gronwall, Lindblad 
 and Staalhane shaft furnace, differing from it principally in 
 regard to the arrangement between the electrodes and the charge, 
 no space being left between them. It is sometimes referred to 
 as the Californian type of furnace from the installation at He"r- 
 oult, California. 
 
 The Rennerfelt furnace is of the arc type and employs essen- 
 tially a two-phase current. There are three electrodes; the mid- 
 dle one is connected to the neutral point and each of the two 
 outside ones to a phase of the two-phase system. By this 
 arrangement of current distribution the arc flame is forced down 
 on the bath, producing a powerful effect. 
 
 The RSchung-Rodenhauser furnace, sometimes called Schb*- 
 nawa-Rodenhauser furnace, is a modification of the Kjellin fur- 
 nace devised by Schonawa and Rodenhauser to obtain higher 
 temperatures, and so be better able to effect purification than 
 with the original. It is of the induction type but in addition to 
 
ELECTRIC PROCESSES 163 
 
 this method of heating employs resistance, for which purpose 
 currents are introduced into the bath through metal electrodes, 
 so that a double effect is obtained. It has a hearth of a very 
 different shape from other induction furnaces. The furnace is 
 constructed for single-phase or for three-phase alternating cur- 
 rent; in the former case the hearth (composed of grooves) is like 
 two Kjellin rings intersecting (forming a figure 8), in the latter 
 case, like three. In both cases these two or three grooves or heat- 
 ing channels open into a distinct open hearth, the working cham- 
 ber, where all the metallurgical operations take place, while the 
 grooves, which have a comparatively small cross-section, form 
 the secondary circuits in which the currents which heat the metal 
 are induced. 
 
 The Ruthenburg process is a link between magnetic separation 
 and the fusion process. It is used for the purpose of agglomerat- 
 ing fine particles of magnetically concentrated ores, as briquet- 
 ting presents certain difficulties or objections. The fine concen- 
 trates are passed through this furnace, the fusion zone of which 
 is a strong magnetic field, and the ore particles are agglomerated. 
 If, in addition, carbon is added to the ore before entering the 
 apparatus, a partial reduction takes place which is subsequently 
 further completed. 
 
 The Schneider or Schneider-Creusot furnace of the induction 
 type and somewhat similar to the Kjellin furnace, is employed, 
 but it is designed to give better circulation of the metal. It is on 
 the principle of a water-tube boiler: a large reservoir is connected 
 to the ends of a tube at an angle, and passing between the arms 
 of a transformer carrying the primary winding; one of the legs 
 of the tube is horizontal, the other slightly inclined. The 
 advantages claimed for such an arrangement are: energetic 
 mixing of the bath; keeping the metal in a closed chamber; 
 the possibility of purification as in an open hearth furnace; 
 and the production of relatively large amounts of metal. 
 
 Wm. Siemens' furnace, which was used only for experimental 
 purposes, was on the arc principle and consisted of a graphite 
 crucible provided with two electrodes: in one form one electrode 
 entered through the bottom and the other through a hole in the 
 cover; in a modification the electrodes were introduced at the 
 sides; a water-cooled metallic electrode was subsequently used 
 instead of the carbon one. 
 
 The Snyder furnace is of the arc type, being an adaptation 
 of Siemens' original furnace with single phase bottom electrode 
 (Vom Baur). 
 
 Stassano furnace : This is an arc furnace, nearly cylindrical 
 in cross-section, and rotating about a vertical axis inclined about 
 7 to the vertical (the furnace may also be stationary). It is 
 provided with three or more large cylindrical electrodes inserted 
 through the sides, and nearly meeting at the center, supplied 
 with a three-phase alternating current. The furnace is usually 
 lined with magnesite, and the charge is introduced at the top, 
 and the molten products are tapped out at the bottom. This 
 furnace has generally been used to produce steel direct from ore, 
 
164 
 
 ELECTRIC PROCESSES 
 
 but pig and scrap may also be employed as in other steel-making 
 processes. In the former method, pure, finely ground ore, with 
 just the right proportion of carbon and flux, is molded into bri- 
 
 Electrode 
 
 PIG. 21. Stassano furnace: vertical section. 
 
 Charging Door 
 
 Electrode 
 
 Spout 
 
 Electrode 
 
 Electrode 
 
 PIG. 22. Stassano furnace: transverse section. AA, of Fig. 21. 
 (Eng. and Min. Jour.) 
 
 quettes and subjected to heat from the arc. The rotation of the 
 furnace helps to keep the ore and carbonaceous matter in contact. 
 The Taussig furnace is of the direct resistance type, the charge 
 being contained in a long narrow channel. 
 
ELECTRIC PYROMETER ELECTROLYTIC IRON 165 
 
 The Vom Baur furnace is of the arc type, and involves the 
 combination of a two-phase, three-wire circuit, three upright 
 electrodes connected to this circuit, a solid bottom for the furnace 
 and an oval-shaped side wall of refractory material. 
 
 The Wile furnace, of the arc type, employs a three-phase 
 current and two top and one bottom electrode; it has been used 
 for melting ferro-manganese, etc. 
 
 The number of furnaces bearing some distinctive or modify- 
 ing name is steadily increasing. While some of them may possess 
 essential differences, the great majority vary only slightly from 
 those now in use or which are known 
 
 Electric Pyrometer ; Resistance Pyrometer. See page 208. 
 
 Electric Resistance Furnace. See page 153. 
 
 Electric Shears. See page 412. 
 
 Electric Steel. See page 153. 
 
 Electric Surface Resistance Furnace. See page 153. 
 
 Electric Tempering. See page 230. 
 
 Electric Welding. See page 503. 
 
 Electrically Driven Rolling Mill. See page 407. 
 
 Electro-affinity. See page 108. 
 
 Electro-cementizing. See page 70. 
 
 Electro -chemical Cleaning. Removing the scale, etc., from iron 
 objects by attaching them to the negative pole in an electrolytic 
 bath. 
 
 Electro-chemical Equivalent. See page 89. 
 
 Electrode Volume. See page 364. 
 
 Electro -galvanizing. See page 371. 
 
 Electro-iron. Iron produced electrolytically. 
 
 Electrolysis. (i) General: see page 89; (2) for iron: see Electro- 
 lytic Iron; (3) in corrosion: see page 365. 
 
 Electrolyte. See page 89. 
 
 Electrolytic Corrosion. See page 108. 
 
 Electrolytic Dissociation. See page 89. 
 
 Electrolytic Iron. That produced by an electrolytic process, the 
 anode consisting of metallic iron (electrolytic refining). It was 
 first carried out successfully by Prof. C. F. Burgess in 1904 by a 
 double operation. Typical analyses are given as follows (Trans. 
 Am. Electrochem. Soc., XXV, 489). 
 
 
 Single refined 
 
 Double refined 
 
 
 O OOI 
 
 Jone 
 
 Silicon, % 
 
 0.003 
 
 0.0013 
 
 Phosphorus % 
 
 020 
 
 o . 004 
 
 Manganese, % 
 Carbon, % 
 
 None - 
 o 013 
 
 None 
 
 O.OI2 
 
 
 99 963 
 
 99 971 
 
 Hydrogen, % 
 
 o .083 
 
 0.072 
 
 O. W. Storey (ibid., XXIX, 357) states that "at least one of the 
 large electrical concerns is turning out (1916) 1000 pounds of 
 electrolytically refined iron per week, with a probable increase to 
 
1 66 ELECTROLYTIC IRON 
 
 several times this output in the near future. The method used 
 is that developed by Burgess and later modified by Watts. 
 The electrolyte consist r, of 1 50 grams of FeSO4'7H 2 O, 75 grams 
 FeCl 2 -4H 2 O, and 120 grams (NHOaSC^ per liter with a specific 
 gravity of 1.125 a * *<? C. Ammonium oxalate is used as an 
 addition agent. The anodes consist of bars of basic open hearth 
 steel. The deposit reaches a thickness of % to % inch be- 
 fore it is necessary to remove the cathode . . . Until 
 recently the only use to which electrolytic iron had been put 
 was in the so-called steel facing of dies and electrotypes.' Its 
 hardness, which makes it suitable for such purposes, is due to 
 hydrogen, either occluded or combined." In the Cowper-Coles 
 process "the electrolyte is a concentrated solution of ferrous 
 chloride with additional organic compounds, such as the cresol- 
 sulphonic acids, and enough iron oxide to make a sort of gruel. 
 The additional iron oxide is used for reducing the acidity and 
 polishing the iron which is deposited as a sheet on a rapidly 
 revolving cathode at a temperature near the boiling point of 
 water! The current density used is about 63 amperes per square 
 foot. The resulting product is brittle due to the presence of 
 several tenths of i % of hydrogen. It also contains about 
 0.50% of impurities, exclusive of hydrogen, while the pig 
 iron used for anodes contains about 7 %. The chlorine 
 content ... is high" (ibid., 358-9). "In 1913 Cowper- 
 Coles obtained a British patent in which he proposes to avoid 
 exfoliation and brittleness ... by suspending an iron sponge 
 in an electrolyte used for refining iron" (ibid., 361). "In 1911 
 Fisher took out patents ... in which he claims that ductile 
 iron may be deposited from a hot solution of ferrous chloride if 
 hygroscopic salts, such as the chlorides of calcium, magnesium, or 
 aluminum are added to the electrolyte. He claims that the 
 ductility of the product increases with the electrolyzing tempera- 
 tures and that perfectly ductile iron is obtained at temperatures 
 varying between 100 and 120 C. The preferred solution consists 
 of a highly concentrated mixture of ferrous and calcium chlorides, 
 450 parts of ferrous chloride and 500 parts of calcium chloride 
 being dissolved in 700 parts of water. Under these conditions a 
 current density of 180 amperes per square foot may be used" 
 (ibid., 359). Ramage took out two patents, one in 191 1 for the use 
 of ferric iron ore, dissolved in sulphuric acid and reduced to the 
 ferrous state by sulphur dioxide, and a later one in which he 
 "dissolves iron in a ferric liquor and electrolyzes the resulting 
 ferrous liquor" (ibid., 359-60). In Boucher's process "the 
 electrolyte is a solution of one or more ferrous salts, such as the 
 sulphate or chloride" (ibid., 360). In Reed's process which also 
 covers "the making of sulphuric acid as a by-product. The 
 electrolyte is a solution of iron sulphate. The anode is made 
 of spongy lead which becomes sulphated as the electrolysis 
 proceeds" (ibid., 361). The Le Fer prp'cess employs pig iron 
 as the raw material. "A cathode revolving in a neutral solution 
 of iron salts is used, the solution being maintained neutral by the 
 circulation of the electrolyte over the surface of the iron" (ibid., 
 
ELECTROLYTIC METHODS ENGINEERING 167 
 
 361). In regard to its properties Storey says (in part ibid., 362) : 
 ' Electrolytic iron when deposited by the usual methods is brittle, 
 due to the hydrogen present. In this form it can be easily 
 broken into smaller pieces and even ground into powder. By 
 heating the iron to a red heat the hydrogen is driven off and the 
 iron becomes ductile, the ductility increasing with the temperature 
 of annealing. Brittle electrolytic iron as deposited is highly solu- 
 ble in acids, being much more readily soluble than zinc. Annealing 
 the iron makes it become more resistant to acid attack than 
 ordinary irons and steels." 
 
 Electrolytic Methods of Etching. See page 288. 
 
 Electrolytic Process. (i) For producing iron: see Electrolytic Iron; 
 (2) for coating: see Protection, page 371. 
 
 Electrolytic Refining. See page 165. 
 
 Electrolytic Theory. Of corrosion: see page 108. 
 
 Electro-metallurgical Process. See page 153. 
 
 Electron ; Electron Theory ; Electronic Theory. See page 81. 
 
 Electronegative Ion. See page 89. 
 
 Electro-percussive Welding. See page 503. 
 
 Electropositive Ion. See page 89. 
 
 Electro-thermal (-ic) Process. See page 153. 
 
 Element. See page 83. 
 
 Eliquation. Separating an alloy by heating it so as to melt the 
 more fusible of its ingredients but not the less fusible (Raymond) ; 
 usually called liquation: see Segregation. 
 
 Ellershausen Process. See page 385. 
 
 Ellis Process. See page 9. 
 
 Elongation. (i) General: see page 336; formulae for: see page 338. 
 
 Eisner Process. See page 30. 
 
 Embrittling (Howe). Causing brittleness. 
 
 Embryonic Crystals. See page 1 20. 
 
 Emery. Impure corundum (alumina) used for grinding and abra- 
 sive purposes. 
 
 Emulsified Carbide. Troostite: see page 276. 
 
 Eminent Cleavage. See page 124. 
 
 Emissive Power. See page 207. 
 
 Emissivity. See page 200. 
 
 Empirical Formula. See page 86. 
 
 Emulsified Pearlite. See page 276. 
 
 Emulsion Martensite. See page 276. 
 
 Enamel ; Enameling. See page 370. 
 
 Encrenee (Fr.). See page 135. 
 
 End Shears. See page 413. 
 
 Endosmose. See Solution. 
 
 Endothermic Reaction. See page 82. 
 
 Endurance Limit. See page 333. 
 
 Endurance Tests. See pages 481 and 482. 
 
 Engineering Standards Committee, The (Brit.). Organized for the 
 purpose of drawing up "British Standard Specifications," defini- 
 tions, and methods of testing for various classes of material and 
 objects. Supported by the following British societies: 
 The Institution of Civil Engineers. 
 
1 68 ENGLISH BRICK EUTECTIC CEMENTITE 
 
 The Institution of Mechanical Engineers. 
 The Institution of Naval Architects. 
 The Iron and Steel Institute. 
 The Institution of Electrical Engineers. 
 English Brick ; Dinas Brick. See page 395. 
 English Formula. For quality: see page 340. 
 English Foundry Iron ; Pig Irons. See page 349. 
 English Scale. Of temperatures: see page 204 
 English Standard Wire Gage. See page 187. 
 English Yield Point. See page 471. 
 Engorgement. See page 35. 
 Entering Angle. In rolling: see page 407. 
 Envelope. See page 126. 
 
 Eolotropic ; Eolotropy. A name given by T. Gray to the phenome- 
 non when a flat bar shows greater elasticity when bent in one 
 direction than in the other. This effect was produced by heating 
 it in a smithy fire, whereby one side was probably converted into 
 cast iron which had higher elasticity in compression than in 
 tension: see page 330. 
 Equalization of Carbon. See page 213. 
 Equalizer. (i) Of blast: see page 34; (2) in cementing: see page 
 
 68. 
 
 Equalizing. In heat treatment: see page 232. 
 Equiaxed Crystal ; Grain. See page 217. 
 Equilibrium. (i) General: see page 326; (2) equation of: see page 
 
 3 2 7. 
 
 Equilibrium Diagram. See pages 271 and 327. 
 Equilibrium Temperature. See page 327. 
 Equivalent. See page 87. 
 Equivalent Proportions, Law of. See page 85. 
 Erhardt Process. See page 491. 
 Erosion. See page 106. 
 Etch-polishing. See page 288. 
 Etching. See page 286. 
 
 Etching Band ; Figure ; Line ; Pit. See page 127. 
 Etching Reagents. See page 287. 
 
 Eudiometer. An instrument for measuring the proportions of 
 various gases which are necessary to form a given compound. It 
 consists of a graduated tube of heavy glass, sealed at one end, into 
 which the gases are introduced and are caused to explode by an 
 electric spark, the open end of the tube being held down on a pad 
 during the explosion. The residual gases are then measured. 
 Euhedral Crystal. See page 122. 
 
 European Process. For malleable castings: see page 258. 
 Eurythronium. See Vanadium. 
 Eustis Process. See page 141. 
 Eutectic. See page 266. 
 Eutectic Alloy. See page 270. 
 Eutectic Austenite. See page 275. 
 Eutectic Austenoid. See page 275. 
 Eutectic Cast Iron. See page 271. 
 Eutectic Cementite. See page 273. 
 
EUTECTIC LINE EXTRUSION 1 69 
 
 Eutectic Line. See page 266. 
 
 Eutectic Mixture ; Point ; Ratio ; Solution. See page 266. 
 
 Eutectic Steel. See page 273. 
 
 Eutectic Temperature. Eutectic point: see page 266. 
 
 Eutectic Time. See page 266. 
 
 Eutecticum. See page 266. 
 
 Eutectiferous Band. See page 127. 
 
 Eutectiform Pattern. See page 127. 
 
 Eutectoid. See page 270. 
 
 Eutectoid Cementite. See page 273. 
 
 Eutectoid Ferrite. See page 272. 
 
 Eutectoid Steel. See page 273. 
 
 Eutectoid Transformation. Of hypoeutectoid Steel: see page 275. 
 
 Eutectomeric Alloy. See page 4. 
 
 Eutexia. See page 267. 
 
 Eutropic Mixture ; Point. See page 270. 
 
 Evans and Spencer Process. See page 64. 
 
 Evaporation. See page 202. 
 
 Evaporative Power. See page 203. 
 
 Even Fracture. See page 178. 
 
 Ewing and Rosenhain's Theory. Of slip bands: see page 282. 
 
 Excess Cementite. See page 273. 
 
 Excess Ferrite. See page 272. 
 
 Excess Substance. See page 266. 
 
 Exchanges, Law of. See page 200. 
 
 Exfoliation. See page 68. 
 
 Exhaust Tuyere. See page 32. 
 
 Exhaustion. Of cement: see page 67. 
 
 Exhaustion Method. For the removal of gases from liquid steel by 
 
 creating a vacuum; tried but not practical. 
 Exosmose. See Solution. 
 Exothermic Reaction. See page 82. 
 Expanded Metal. Sheets in which a series of short, disconnected, 
 
 transverse cuts have been made, and the sheets then extended 
 
 longitudinally, producing the effect of a framework or grille. 
 Expanding Cupola. See page 182. 
 Expansion. (i) General: see page 204; (2) coefficient or factor of: 
 
 see page 204. 
 
 Expansion Crack. See Crack. 
 Expansion Pyrometer. See page 205. 
 Explosion Door. See page 33. 
 Extension. See page 336. 
 Extensometer. See page 471. 
 Exterior Shrinkage. See page 54. 
 External Conductivity. See page 200. 
 External Forces. See page 331. 
 Extra Lattens. Of sheets: see page 433. 
 Extraction Process. One where a metal is smelted or reduced from 
 
 its ore. 
 
 Extrapolation. See Curve. 
 
 Extrusion. The forcing of a substance through a die or aperture. 
 Extrusion, Centrifugal. See page 121. 
 
1 70 EXUDE EYERMANN PROCESS 
 
 Exude. To ooze out, either under heat or pressure, e.g., for a more 
 fusible or a softer substance to exude from one which is less fusible 
 or harder. 
 
 Eye. (i) The peep hole, covered with glass, in the tuyere of a 
 blast furnace; (2) the hole for the pin in the end of an eye bar. 
 
 Eye Piece. See page 285. 
 
 Eyermann Process. See page 318. 
 
F. (i) Fahrenheit scale: see page 204; (2) chemical symbol for 
 fluorine: see page 84. 
 
 Fe. Chemical symbol for iron (Latin, ferrum), q.v. 
 
 Fl (rare). Chemical symbol for fluorine: see page 84. 
 
 F. P. Freezing point. 
 
 Face. Of a crystal: see page 119. 
 
 Face-hardened Armor Plate. See page 8. 
 
 Faceless Crystal. See page 122. 
 
 Facing Sand. See page 298. 
 
 Faggot (Eng.); Fagot ; Fagoted Iron. See page 378. 
 
 Fahrenheit Scale. Of temperatures : seepage 204. 
 
 Falk Method. See page 65. 
 
 Fall. (i) Of meteorites: see page 290; (2) of malleable castings: 
 see page 257. 
 
 Fall of the Beam. See page 469. 
 
 Falling Seam. See page 489. 
 
 Falling Weight Test. Drop test: see page 481. 
 
 False Block. See page 195. 
 
 False Pass. See page 405. 
 
 Fament Process. See page 385. 
 
 Faraday's Laws. See page 89. 
 
 Faraday's Theory. Of passivity: see page 364. 
 
 Farrar Process. See page 385. 
 
 FatT Coal. See Coal. 
 
 Fat Lime. See Flux. 
 
 Fat Sand. Sand for molding which contains a large amount of clay 
 or alumina. 
 
 Fatigue. See page 333. 
 
 Fatigue Limit ; Stress. See page 333. 
 
 Fatigue Test. See page 482. 
 
 Fauld (obs.). The tymp arch or working arch of a jfurnace (Ray- 
 mond). 
 
 Faulting Foliation. See page 124. 
 
 Feather. See page 58. 
 
 Feed Roll. See page 415. 
 
 Feeder ; Feeding Gate ; Feeding Head. See pages 56 and 299.' 
 
 Felsitic Structure. See page 125. 
 
 Fermentation (obs.). The boiling stage in the puddling process. 
 
 Fern Leaf Crystal. See page 122. 
 
 Ferranti Process. See page 155. 
 
 Ferrate. A chemical compound: see Iron. 
 
 Ferrated Carbides. See page 278. 
 
 Ferric Acid. See Iron. 
 
 Ferric Oxide Theory. Of puddling: see page 378. 
 
 Ferrite. (i) A chemical compound: see Iron; (2) pure iron: see 
 page 272. 
 
 Ferrite Ghost. See page 289. 
 
 171 
 
1 7 2 FERRITE POINT FILLET 
 
 Ferrite Point. See page 273. 
 
 Ferrite-refinement Principle. See page 341. 
 
 Ferrite Steels. Those consisting principally of ferrite; hypo-eu- 
 
 tectic steels. 
 
 Ferro-Alloys. See page 351. 
 Ferro-Aluminum. See page 351. 
 Ferro-Brass. See page 372. 
 Ferro-Carbon. See page 351. 
 Ferro-Carbonyl. See Carbon. 
 Ferro-Chrome ; Ferro -Chromium. See page 352. 
 Ferro -Ferrite. See page 272. 
 Ferro-Manganese. See page 352. 
 Ferro-Molybdenum. See page 353. 
 Ferro-Molybdenum Hardenite. See page 275. 
 Ferro-Nickel. See page 353. 
 Ferronite. See page 277. 
 Ferro-Phosphorus. See page 353. 
 Ferro-Products. See page 351. 
 Ferro -Silicon. See page 354. 
 Ferro-Sodium. See page 355. 
 Ferrostatic Pressure. See page 56. 
 Ferro-Steel. A trade name for semi-steel (q.v.). 
 Ferro-Titanium. See page 355. 
 Ferro -Tungsten. See page 355. 
 Ferro -Vanadium. See page 356. 
 Ferrous Acid. See Iron. 
 Ferrous Alloy. See Alloy. 
 
 Ferrous Structure. That of ordinary or carbon steels or cast irons. 
 Ferruginous. Carrying or containing iron. 
 Ferruginous Manganese Ore. See page 245. 
 Ferro-Concrete. Reinforced concrete. 
 Fery Pyrometers. See page 207. 
 Ftetch Up. Of carbon: see Recarburization. 
 Fettling. (i) Of castings: see page 58; (2) of a furnace: see pages 
 
 315 and 376. 
 
 Fiat Gage. See page 187. 
 Fiber; Fibre. See pages 125 and 337. 
 Fiber Stress. See page 337. 
 Fibriform Structure. See page 125. 
 Fibrous Fracture. See page 178. 
 Fibrous Iron (obs.). Wrought iron which is tough, comparatively 
 
 soft, and neither cold nor red-short in a sensible degree (Percy). 
 Fibrous Silica. See Salamander. 
 Fibrous Structure. See page 125. 
 Fibrox. See page 398. 
 Field. Seepage 291. 
 Field Coat. See page 365. 
 Fiery Fracture. See page 178. 
 Figure of Merit. See pages 8 and 340. 
 Filament. See page 125. 
 Fill Out. In rolling: see page 414. 
 Fillet. The curved junction of two surfaces which would otherwise 
 
FIN FIRST STRAND 173 
 
 meet at an angle. Its object is to lessen the danger of cracking, 
 
 and it is used particularly in connection with castings, machined 
 
 material, and rolled sections. 
 Fin. See Forging. 
 
 Final Additions. See Recarburization. 
 Final Slag. See Slag. 
 Find. See page 290. 
 Fine-grained Fracture. See page 1 78. 
 
 Fine-grained Iron ; Metal ; Pig. Pig iron having a fine fracture. 
 Fine Metal. See page 383. 
 Finer. See page 316. 
 Finer's Bar. See page 75. 
 Finer's Metal. See page 383. 
 Finery ; Finery Fire. See page 382. 
 Finger. See page 411. 
 Fining. See page 383. 
 Finished. Material which is ready for the market without any 
 
 further treatment. Blooms and similar material are termed 
 
 semi-finished, except only when they are sold as such, when they 
 
 may be called finished. 
 Finished Black Plate. See page 431. 
 Finished Charcoal Bar. See page 75. 
 Finished Iron. A name sometimes applied to merchant (wrought 
 
 iron) ; muck bar piled and rerolled. 
 Finished Material Analysis. See page 82. 
 Finished Products. (i) General: see page 411; (2) mills for: see 
 
 page 413. 
 
 Finisher. See page 316. 
 Finishing Block. See page 508. 
 Finishing Metal. See Recarburization. 
 Finishing Rolls ; Stand. See page 414. 
 Finishing Temperature. See page 218. 
 Finkelstein's Theory. Of passivity: see page 364. 
 Fir-tree Crystal. See page 122. 
 Fire Assaying. See page 82. 
 Fire Bar ; Bed. See page 183. 
 Firebrick. See page 396. 
 Fire Bridge. See page 183. 
 Fireclay ; Fireclay Brick. See page 396. 
 Fireclays, Grades. See page 396. 
 Fire Crack. (i) In rolling: see page 405; (2) of refractories: see 
 
 page 395. 
 
 Fire Gases. See page 202. 
 Fire Hole. See page 114. 
 Fireplace. See page 183. 
 Firestone. See page 395. 
 Firing Test. See page 482. 
 First Annealing. Of sheets: see page 431. 
 First Class Foam Cells. See page 121. 
 First Order Cells. See page 121. 
 First Pickling. Of sheets: see page 431. 
 First Strand. See page 415. 
 
174 FISHER PROCESS FLUID COMPRESSION 
 
 Fisher Process. See page 166. 
 
 Fissile. See page 124. 
 
 Fissure. See Crack. 
 
 Fix (Eng.). See page 376. 
 
 Fixed Carbon. See Fuel. 
 
 Fixed Converter. See page 17. 
 
 Fixed Elements. See page 70. 
 
 Fixed Furnace. See page 312. 
 
 Fixed Points. Of a temperature scale: see page 204. 
 
 Flake. See pages 71 and 178. 
 
 Flame. See page 203. 
 
 Flame Contact Furnace. See page 181. 
 
 Flame Cut. Of material cut by means of an oxyacetylene or 
 oxyhydrogen flame. 
 
 Flame Furnace. See page 181. 
 
 Flameless Combustion. See page 203. 
 
 Flanch (obs.). Flange. 
 
 Flange Steel. Steel of suitable quality to be bent (flanged) cold. 
 
 Flanging. See Cold Working. 
 
 Flash. See Forging. 
 
 Flash Annealing. See page 232. 
 
 Flash Heating. See page 228. 
 
 Flash Point. See page 202. 
 
 Flask. See page 297. 
 
 Flask Annealing. See page 58. 
 
 Flat ; Flat Iron ; Flat Bar Iron. A long narrow strip or plate, usually 
 produced on a bar or merchant mill. 
 
 Flat Roll. See page 404. 
 
 Flatter. In forging, a swage used to flatten. 
 
 Flatting Mill. A machine for flattening wire. 
 
 Flavite. See pages 69 and 279. 
 
 Flaw. Defect. 
 
 Flexure ; Flexural Rigidity ; Resilience ; Strength ; Stress. See 
 pages 330 and 33 7. 
 
 Flicker Photometer. See page 208. 
 
 Flint Hardness. See Hardness. 
 
 Floating. Of cores: see page 298. 
 
 Flohr Process. See page 21. 
 
 Floor Sand. See page 301. 
 
 Floss; Floss Hole. See page 375. 
 
 Flow. See page 209. 
 
 Flow Gate. See page 299. 
 
 Flow Lines. See pages 283 and 289. 
 
 Flue. A passage for air or other gases. 
 
 Flue Bridge. See page 183. 
 
 Flue Cinder. See page 375. 
 
 Flue Dust. See pages 33 and 44. 
 
 Fluid Bottom. See Lining. 
 
 Fluid Compressed Steel. Steel which has been subjected to com- 
 pression before it has entirely solidified: see page 63, 
 
 Fluid Compression. See page 63. 
 
FLUID METAL FLUX 1 7 5 
 
 Fluid Metal. Suggested by Von Ehrenwerth for slagless iron 
 products. 
 
 Fluid Movement. See page 281. 
 
 Fluid Pig Iron. Suggested by Von Ehrenwerth to replace hot 
 metal. 
 
 Fluid Rolling Process, Norton. See page 65. 
 
 Fluid Stress. See page 332. 
 
 Fluorspar. Also called spar or calcium; fluoride of calcium, 
 CaF2; used as a flux: see below. 
 
 Flush. See pages 36 and 438. 
 
 Flushed Bars. See page 71. 
 
 Flushing Hole. See page 32. 
 
 Flussofen. See page 135. 
 
 Flute ; Fluting. In a plate which has been rolled out longer on one 
 side than on the other; when it is straightened the long side 
 shows flutes. or waves; where the center has been rolled out 
 longer than the outside, producing the same effect in the middle, 
 the plate is said to be buckled. 
 
 Flux. (i) In the crucible process: see page 115; (2) in welding: 
 see page 501. 
 
 Flux. A material used in smelting metals for the purpose of 
 combining with the gangue of the ore and producing a suitable 
 slag (a) by making it sufficiently fusible, and (6) by combining 
 with certain impurities and preventing them from entering 
 or remaining in the metal. The term is also used for a sub- 
 stance added in a refining (oxidizing) process to make the slag 
 more fusible. A flux may be either acid or basic depending 
 upon its chemical properties. The principal basic flux is 
 limestone, CaCO 3 , also called lime, or raw limestone occurring 
 naturally, and containing small amounts of silica, magnesia, 
 alumina, iron, etc. In color it is ordinarily gray, white, or 
 slightly yellow, and is massive (non-crystalline) in structure. 
 If crystallized, it is known as calcite. For blast furnace work 
 the silica should generally be less than 5 %, and for basic Bessemer 
 and basic open hearth practice not over i or 2%. The 
 magnesia, as well as the iron and alumina, is not especially 
 objectionable for its use as flux, but as a rule they are less than 
 4%. The material is sometimes calcined to expel the carbonic 
 acid, but the action is usually not perfectly complete; it is then 
 termed burnt lime or quick lime. If, owing to imperfect calcina- 
 tion or the presence of other substances it slacks with difficulty 
 (better, however, with hot water) it is designated as poor lime ; 
 if it slacks easily, as fat lime. Magnesia and dolomite do not 
 find much application as fluxes (see Refractories). Fluorspar 
 or calcium fluoride, CaF 2 , sometimes called spar, occurs in 
 translucent or transparent crystals, which may be colorless, 
 light yellow, or purple in color. It should contain less than 10% 
 of impurities, but calcite, which is frequently present, is not par- 
 ticularly objectionable; the silica should be less than 2 %. A by- 
 product, sometimes employed, contains about 50% of calcium 
 fluoride mixed principally with lime; this, as well as fluorspar, is 
 occasionally called calcium. This flux is used principally in 
 
1 76 FLUX LINE FORGING 
 
 open hearth practice for thinning basic slags which are too 
 viscous. Calcium chloride, alkaline salts, etc., are sometimes 
 used in purification processes (q.v.). The only acid flux is sand, 
 which is practically never used as an addition to a slag which is 
 too viscous from high lime: it, as well as borax, is used in weld- 
 ing (q.v.) to obtain a fusible cinder. 
 
 McClenahan's process for smelting certain southern red iron 
 ores was to use common salt (NaCl) instead of limestone, claim- 
 ing that "limestone has no affinity for the aluminous components 
 of the red ore." 
 
 Flux Line ; Stick. See page 115. 
 
 Fly. See Ladle. 
 
 Fly Hammer. See page 196. 
 
 Flyer. See Cold Working. 
 
 Flying Shears. See page 413. 
 
 Foam; Foam Cell ; Wall. See page 121. 
 
 Foaming. See Frothing. 
 
 Foeppl's Method. Of determining hardness: see page 478. 
 
 Foerster and Schmidt Theory. Of passivity: see page 364. 
 
 Folding. See page 124. 
 
 Foliation. See page 1 24. 
 
 Forbes Process. See page 369. 
 
 Forced Solution. See page 279. 
 
 Fore Blow. See page 21. 
 
 Fore Hearth. (ij Of a blast furnace: see page 32; (2) of an open 
 hearth furnace: see page 315. 
 
 Fore Plate. See page 415. 
 
 Fore-Spar Plate. See page 135. 
 
 Foreign Pig Iron. See page 344. 
 
 Forge. (i) To work a piece of metal with a hammer or a press; 
 (2) a power hammer; (3) a plant for the manufacture of (wrought) 
 iron blooms direct from the ore: see page 134; it consists of a 
 furnace or forge fire, a blowing apparatus and a hammer; (4) 
 later, this term was applied to that part of a (wrought) iron 
 works where the balls were hammered or squeezed, and then 
 rolled into muck bar; that part of the works where the muck 
 bar was reheated and rerolled into finished iron was called 
 the mill. 
 
 Forge Cinder. See Slag. 
 
 Forge Coal. See Coal. 
 
 Forge Effect. In electro-percussive welding: see page 504. 
 
 Forge Fire. Forge, q.v. 
 
 Forge Iron ; Pig. See page 344. 
 
 Forge Process. See page 74. 
 
 Forge Rolls ; Train. See page 413. 
 
 Forging. The operation of working metal or of changing its shape 
 by striking it a sharp blow (usually while hot) with a hammer or 
 other suitable instrument; also the object so produced. The ac- 
 tion^ of a hydraulic press is frequently termed forging (hydraulic 
 forging), but as the action is more of a steady squeeze the desig- 
 nation pressing would appear to be preferable. To indicate the 
 use of a hammer, the term hammer forging is employed. The 
 
FORGING CRACK FRACTURE 1 7 7 
 
 operation of hammering puddle balls was formerly called shin- 
 gling or nobbing. The term smithing (Eng.) is sometimes used 
 for working a piece, especially by hammering, for the purpose of 
 straightening or flattening it. Removing or correcting the irregu- 
 larities of a piece by hammering (sometimes cold) may be referred 
 to as dressing or hammer dressing. Where a forging, for 
 example a projectile, is made by hot punching a portion of its 
 length, the billet may be placed in a die and forced down until it 
 completely fills it, an operation known as setting down. Drop 
 forging (and the object) is a process designed for making a large 
 number of objects exactly the same. It consists in forging a 
 suitable piece of steel between dies under a hammer, the lower 
 die being attached to the anvil block, while the upper is fastened 
 to the hammer itself, and moves up and down with it. When the 
 object is simple, one set of dies may suffice, but with more com- 
 plicated pieces, two or more are necessary for roughing and finish- 
 ing. The fin or flash, formed at the sides of the piece where a 
 small portion of the metal is forced out between the edges of the 
 dies, is dressed off, and any other required machining is done. 
 Hollow forging is where a piece, usually a heavy shaft or column, 
 is bored and then forged out on a mandrel. Its object is to secure 
 better working of the metal than would be the case with a solid 
 piece of large cross-section. See also Hammer and Press. 
 
 Forging Crack. See Crack. 
 
 Forging Strain. A strain set up in forging at too low a temperature, 
 or where a part receives more work than another. 
 
 Forging Test. See page 476. 
 
 Form. Mold. 
 
 Formation of Crystals. See page 120. 
 
 Former. See page 405. 
 
 Formula. Chemical Formula: see page 86. 
 
 Fornoconvertisseur. See page 318. 
 
 Forsyth Process. See page 62. 
 
 Forty-eight-hour Coke. See page 95. 
 
 Fosberg's Swedish Hearth. See page 76. 
 
 Fossil Ore ; Fossilif erous Red Hematite. See page 244. 
 
 Foster Pyrometer. See page 207. 
 
 Foul Gas Main. See page 96. 
 
 Founding ; Foundry. See page 53. 
 
 Foundry Coke. See page 96. 
 
 Foundry Iron ; Pig. See page 344. 
 
 Foundry Pit. See page 57. 
 
 Four-high Mill, Bleckley's. See page 417. 
 
 Four-sided Charcoal Wire. See page 509. 
 
 Fournier Pyrometer. See page 209. 
 
 Fox Tail. See page 79. 
 
 Fracture. The irregular surface, and its appearance, produced 
 when a piece of metal is ruptured or broken. The terms fracture 
 and rupture are frequently used interchangeably; it is, however, 
 desirable to restrict them as just indicated. 
 
 Howe (Metallog., 527-8) classifies fractures as follows: 
 12 
 
1 78 FRACTURE 
 
 1. Granular or intergranular, caused by rupture passing along 
 grain boundaries instead of across the crystalline grains them- 
 selves. 
 
 2. Crystalline, trans-crystalline, or intra-crystalline, caused 
 by rupture passing across the crystalline grains themselves. 
 
 3. Silky, caused by the thread-like drawing out of the frag- 
 ments of the crystals in the act of rupture. 
 
 4. Hackly or hooked, sharp or jagged and irregular, which may 
 be referred to the drawing out of the ferrite in the act of rupture. 
 
 5. Fibrous and slaty, caused by rupture occurring consecutively 
 through distinct layers. 
 
 6. Columnar, as in the case of the outer parts of ingots and other 
 castings of quiet or piping steel. 
 
 Granular fractures better reflect the light than those which are 
 trans-crystalline; they are also more frequent with overheated or 
 highly heated steel and are called coarse-grained, rough, bright 
 crystalline, bright, or granular-crystalline ; if especially coarse and 
 bright, brilliant, splendent, sappy, or fiery and, in the case of 
 crucible steel held too long in the pot, scorched or, if pieces of 
 fuel have fallen in, staring. Where tool steel or other steel high 
 in carbon has been heated in such a way as to convert some of the 
 carbon into graphite, it is said, from the appearance, to have a 
 black fracture. (or black center). Flaking is the scaly fracture in 
 high-speed steels due to being soaked at high temperatures and 
 afterwards not forged sufficiently to break up the coarse grain; 
 this condition disappears on annealing, but reappears on rehard- 
 ening (Brearly ) . The trans-crystalline fractures are also referred 
 to as fine grained, smooth, even, or amorphous, but preferably for 
 the last should be used the terms porcelanic or aphanitic ; due 
 to the absence of pronounced luster they are also called dull or, 
 more rarely, gray-granular. 
 
 If wrought iron is nicked all around and broken short off with 
 a sharp blow, the fracture may be granular; but if nicked on only 
 one side, and bent slowly away from the nick, the intermingled 
 slag causes the iron to break in layers, and the fracture is barked, 
 fibrous, laminated, or splintery. Such an appearance is not often 
 found in the case of plain carbon steel, but is obtained with 
 screw stock grade (high in manganese sulphide), also with certain 
 alloy steels, especially those containing nickel. Material which 
 has been broken at one time, as by a single blow, so quickly that 
 the piece snaps off without any appreciable bending, gives rise 
 to a brittle fracture or sudden fracture, in contradistinction to the 
 tough fracture resulting from considerable bending and tearing. 
 
 If the fracture shows very sharp points it is sometimes called a 
 needle fracture ; if, as in the case of certain zinc-copper or tin- 
 copper alloys, it has the appearance of a number of little shells, it 
 is termed conchoidal. 
 
 A star fracture is the term applied to the fracture of certain 
 broken tensile test specimens, which are generally found only 
 when the elastic limit is about 90,000 Ibs. per square inch or over. 
 It has the appearance of a star with raised ribs (or rays) radiat- 
 ing outwards from a common center. A fracture is referred to as 
 
FRACTURE TEST FREE IRON 179 
 
 composite when it consists of more than one form or type. An 
 irregular fracture is sometimes spoken of as uneven. Fractures 
 (usually of slags, etc., which are non-metallic) having a glassy 
 appearance or shape, are termed vitreous or vitriform. 
 
 Where a piece has broken under alternate bending stresses, 
 the material usually gives way gradually, i.e., one part at a time, 
 and the first part to give way gives rise to rubbing and blacken- 
 ing of the opposed surfaces, while the last part is usually more or 
 less granular; this is known as a progressive fracture or a detail 
 fracture. Before rupture was complete there would be found a 
 partial fracture. A detail fracture may be started either on the 
 outside or the inside, in the latter case giving rise to an internal 
 fracture whose appearance may throw valuable light on the con- 
 dition of strains which brought it about. Detail fractures are 
 sometimes attributed to what is erroneously termed cold crystal- 
 lization, it being claimed that actual growth of the grain occurred 
 while the given piece was in service. This has been thoroughly 
 disproved as regards ordinary temperatures for iron and steel, and 
 was probably due to the fact that the fracture of a tensile test 
 specimen, or where there has been considerable deformation, 
 always has a much finer appearance than where the rupture was 
 abrupt. 
 
 Fremonville investigated fractures occurring in metals, by 
 means of observations on ruptured glass and bitumen. He enun- 
 ciated the following laws in regard to his bursting theory: i. The 
 origin of all breakages is a burst taking place in the interior of the 
 body, and only develops itself by a succession of bursts, which 
 are general in the case of sudden fractures and localized in the case 
 of progressive fractures. 2. The first burst the origin of all 
 rupture takes place in a region where the principal stress is 
 positive, but not necessarily at a point where that stress reaches 
 its maximum value. Other things being equal, the stress normal 
 to the principal stress determines the danger of rupture (Inst. 
 Met., 1915, I, 318). 
 
 In tensile testing, if the metal is relatively soft and ductile, the 
 entire exterior portion may be extended more than the interior 
 which, accordingly, is depressed, and this effect gives rise to a 
 cup fracture ; if only a portion of the exterior has been so extended, 
 a half-cup, etc. If the piece breaks at an angle, it is called an 
 angular, oblique, or slip fracture. If the fracture is partly 
 angular and partly a cup, it is known as an irregular fracture. 
 
 Fracture Test. See page 483. 
 
 Fragility. Brittleness, q.v. 
 
 Fragmental Structure. See page 125. 
 
 Fragmentation Test. See page 483. 
 
 Franche-Comte Process. See page 76. 
 
 Franklinite. See page 244. 
 
 Fredenhagen Theory. Of passivity: see page 364. 
 
 Free Carbon Dioxide. See page 107, 
 
 Free Cementite. See page 2 73. 
 
 Free Fenite. See page 272. 
 
 Free Iron (Sorby). See page 272. 
 
1 80 FREE PHOSPHIDE FURNACE 
 
 Free Phosphide. See page 289. 
 
 Freedom, Degree of. See page 327. 
 
 Freezing ; Freezing Point ; Freezing Point Curve. See page 201. 
 
 Freezing Range. See page 267. 
 
 Fremont Machine. For impact testing: see page 482. 
 
 Fremont's Method. To determine hardness: see page 478. 
 
 French Calorie. See page 199. 
 
 French Metal. See Antimony. 
 
 Fresh Iron. See page 364. 
 
 Freshen. Sometimes used in the sense of to purify, e.g., when air is 
 blown through molten pig iron. 
 
 Friable. Easily crumbled; reducible to powder. 
 
 Frick Furnace. See page 155. 
 
 Friction Drive. See page 418. 
 
 Frigo-Tension. See Cold Working. 
 
 Frischen Process. See page 383. 
 
 Fritting. Becoming pasty and melting down on heating; the 
 action of some soft coals. 
 
 Fritz Mill. See page 408. 
 
 Frondescent Hematite. See page 244. 
 
 Frontal Hammer ; Helve. See page 197. 
 
 Frothing. Also called foaming ; the condition of a slag in a refining 
 process which is viscous and becomes puffed up by the carbonic 
 oxide gas evolved from the oxidation of the carbon in the metal 
 underneath. 
 
 Frothy. (i) Of slags, the same as frothing; (2) of steel, unsound 
 from foaming or rising in the mold. 
 
 Frozen Continent. See page 54. 
 
 Fryer Process. See page 30. 
 
 Fuel. From a commercial standpoint a substance which can be 
 burned economically for the generation of heat to be applied 
 to some useful purpose. Fuels may be either solid, liquid, or 
 gaseous. They consist of combustible matter (matter which will 
 burn) and ash or matter which will not burn. The combustible 
 matter consists of carbon and hydrogen, combined or uncom- 
 bined. If the fuel is solid, the combustible matter is divided into 
 volatile matter which is driven off upon the application of heat, 
 and fixed carbon which is left behind. The residue, containing 
 both the fixed carbon and the ash, is sometimes referred to as the 
 coke. 
 
 Fuel Gas. Any gas suitable for use as a fuel; sometimes used more 
 particularly for producer gas or water gas. 
 
 Fuliginous (rare). Smoky or dirty. 
 
 Full Radiator. See page 207. 
 Full-size Test. See page 468. 
 
 Fuller. A tool with a face of sharp curvature, fitting in the socket 
 of an anvil, on which bars are hammered down. 
 
 Furgen (obs.). A round rod used for sounding a bloomary fire 
 (Raymond). 
 
 Furnace. A structure in which heat is generated by the com- 
 bustion of fuel, more particularly for the smelting of ore or 
 the treatment of metal. They may be classified according to: 
 
FURNACE 181 
 
 I. The nature of the fuel: 
 
 1. Solid fuel: coal, coke or charcoal furnace. 
 
 2. Liquid fuel: oil furnace. 
 
 3. Gaseous fuel: gas furnace. 
 II. Method of applying the heat: 
 
 4. Direct heating furnaces, where the fuel or flame comes in 
 contact with the charge: 
 
 (a) Contact heating furnaces, where solid fuel is in contact 
 or mixed with the material to be heated, as in the blast 
 furnace. 
 
 (b) Flame contact furnace or flame furnace, where only 
 the flame strikes the charge, as in a reverberatory 
 furnace. 
 
 5. Indirect heating furnaces, where the charge does not 
 come in contact with either the fuel or the flame, but is 
 heated by conduction and radiation through a wall, as in a 
 muffle furnace. 
 
 III. The form or construction of the furnace. This classifica- 
 
 tion will be more particularly followed below. 
 
 IV. The purpose for which the furnace is intended, e.g., 
 
 an annealing furnace. Except where a special type 
 is introduced, such furnaces will be found discussed in 
 connection with the special process involved. 
 
 Heap, pile, or mound: This is the oldest form of heating 
 arrangement and is employed only for roasting or calcining. 
 The material, mixed with solid fuel, is piled up, usually without 
 any covering (open), sometimes, as in the case of the old method 
 for the preparation of charcoal, covered with earth or turf, 
 small openings being left for draft. 
 
 Stall: This is somewhat similar to the heap, but usually has 
 brick walls on three sides, the top and the front being left open. 
 This insures a more even heating than the heap. It is used for 
 roasting and calcining, formerly also for coking coal. 
 
 Oven: This name is sometimes used synonymously with 
 furnace (the German word for furnace is Of en), e.g., a furnace 
 of the reverberatory type for drying molds is called a drying 
 oven. It is principally restricted to furnaces for making coke 
 (q.v.); an oven for annealing was called a calcar. 
 
 Shaft furnace: This consists of vertical brick walls, and is 
 usually circular in cross-section, with the height several times 
 the inside diameter. The material is charged at the top and 
 removed at the bottom. The top may be provided with a 
 bell and hopper (see page 32) or simply left open. The fuel 
 is usually solid and is charged in lumps at the top mixed with 
 the other materials, and the air for combustion may be sup- 
 plied by natural draft, or more generally under pressure through 
 pipes or tuyeres near the bottom. Oil or gas is sometimes 
 employed for fuel, in which case it is injected with the air through 
 similar pipes at the bottom. 
 
 Kilns are shaft furnaces for roasting or calcining ore, limestone, 
 etc., where a very high temperature is not required, and may be 
 fired in any of the ways described above, but generally with coke, 
 
I 82 FURNACE 
 
 and the employment of a gentle blast. They are relatively short, 
 up to about 30 feet, and as a rule are of uniform diameter through- 
 out. A furnace of this type, somewhat resembling a beehive coke 
 oven, is generally used for firing bricks (brick kiln or brick 
 oven). 
 
 Cupolas are similar to kilns and are used for melting pig 
 iron. They are usually of the same diameter throughout, 
 but may have the walls slightly divergent at about the middle, 
 rarely called an expanding cupola. They are practically always 
 fired with coke and a gentle blast, generally cold, but occasionally 
 slightly preheated, in which case it is termed a hot-blast cupola, 
 and, in contradistinction, the former would be referred to as a 
 cold-blast cupola. The blast may be supplied to each tuyere 
 separately from a fan, but usually through a casing surrounding 
 the furnace, similar to the bustle pipe of a blast furnace, called an 
 air chamber or air belt. An arrangement is sometimes made by 
 which the tuyeres can be placed at different levels (adjustable 
 tuyere). The bottom of the cupola is called the hearth or well. 
 There are holes provided at the bottom for tapping the molten 
 cinder and the iron. The tapping hole is closed with a plug of 
 clay (bod, bot, or bott) thrust in on the end of an iron rod (bot 
 stick) ; the operation of closing the hole is sometimes called stop- 
 ping in or hotting up. If the bottom is built on a solid foundation 
 of masonry, it is called a stationary bottom, but, according to 
 modern practice, it is generally closed with a hinged plate of 
 cast iron which can be opened to dump the material remaining 
 in the cupola after a run, and called a drop bottom. Foundry 
 cupolas may have an arched hole (breast hole) above the bottom 
 which can be opened for cleaning out the cupola, and is closed 
 with an iron door (breast plate). A reservoir cupola, tank 
 cupola, or compound cupola is one with a greater diameter at the 
 bottom, or provided with a connecting chamber, so a greater 
 amount of iron may be kept molten. A very small furnace for 
 melting purposes, which can be picked up by a crane for pouring 
 the molten iron into a ladle, has been styled a cupola crucible. 
 Cupolas used in connection with the Bessemer process are charged 
 at the top; foundry cupolas through a hole on the side near the 
 top (charging door). A cupola is said to be ready to run when 
 the pig iron has melted. The man in charge is called the melter. 
 
 Shaft furnaces for smelting iron ore are termed blast furnaces 
 (ff.*). 
 
 Hearth: This is a rectangular chamber of only moderate 
 depth, in which the charge is heated in contact with solid fuel, 
 the walls and bottom of which are usually of cast iron, frequently 
 water-cooled. If the top is enclosed with a hood, it constitutes 
 a closed hearth, otherwise, an open hearth. The air for combus- 
 tion is blown in through one or more tuyeres. The action may be 
 reducing when used for some direct process (q-v.) t or oxidizing 
 when used for refining (see Purification Processes and Charcoal 
 Hearth Processes). 
 
 Reverberatory furnace (air furnace) : In this furnace the charge 
 is heated, not by direct contact with the fuel, but by the gaseous 
 
FURNACE 183 
 
 products of combustion (the flame) and, as a rule, no blast is 
 employed. Where a very strong draft is maintained it may be 
 termed a wind furnace. It consists of the heating chamber, 
 called the hearth or laboratory, on the bottom or sole (also called 
 the hearth or rarely the firebed). of which the charge rests. At 
 one end is a small chamber (fireplace) in which the fuel is burned; 
 at the other end the chimney or stack. At each end of the hearth 
 is a low wall (bridge or bridge wall); that next the fireplace is 
 called the fire bridge ; that next the chimney, the flue bridge or 
 altar. The roof usually has a very flat arch, springing from the 
 side walls, and covers both the fireplace and the hearth; it is 
 highest over the fireplace, and thence slopes downward to the 
 chimney flue, so that the flame, after striking the roof, will be 
 deflected down (reverberated) upon the charge. If the roof is 
 high enough, so that the flame does not actually touch the charge, 
 which is then heated by radiation from the roof, the furnace is 
 termed a radiation furnace. The fuel is usually solid, and is 
 supported on grate bars (fire bars) which may be easily removed to 
 permit of cleaning and replacement;. The furnace may be used 
 for heating purposes, or for melting operations as in the puddling 
 process. In the former case it may be built entirely of brick 
 (with iron tie rods, etc.), but in the latter, the hearth generally 
 has cast-iron sides and bottom, either air-cooled or water-cooled. 
 The charge is usually introduced through one or more doors 
 (charging doors) in the side: for roasting purposes, sometimes 
 through hoppers in the roof. 
 
 Recuperative furnaces are similar to ordinary reverberatory 
 furnaces, but the air for combustion (under a slight pressure) 
 is preheated by entering through pipes in the chimney flue, 
 around which the products of combustion pass. 
 
 Regenerative furnaces are special reverberatory furnaces 
 using either gaseous or liquid (practically never powdered) 
 fuel, in which the air alone, or both the air and the fuel, are pre- 
 heated in special chambers (regenerators) situated at each end 
 of the furnace, between the furnace and the stack (see Heat). 
 In this arrangement the air and fuel are burned alternately at 
 each end, one set of regenerators being heated by the products 
 of combustion while on their way to the stack, while the other set 
 is heating the air and fuel before entering the furnace proper. 
 In this country, when this type js used for making steel it is 
 called an open hearth furnace or a Siemens furnace (see Open 
 Hearth Process). 
 
 Crucible furnaces are properly furnaces in which crucibles 
 (q.v.) are heated and may be of various types. The crucibles 
 may be set directly on the solid fuel, supported on grate bars in a 
 small, short, shaft furnace; heated in similar chambers with gas 
 preheated in regenerators (regenerative crucible furnace) ; or on 
 the hearth of a regenerative reverberatory (open hearth) furnace. 
 
 Muffle furnaces consist of a closed chamber in which the 
 charge is heated out of contact with the fuel or the products 
 of combustion. Converting furnaces (used for cementation) 
 are of this type, but are frequently termed retort furnaces. In 
 
184 FURNACE ADDITIONS FURNACE TEST 
 
 England this name is sometimes applied to a fire used for heating 
 crucible steel ingots, etc., similar to a smith's forge, consisting of 
 a hollow fire made with large lumps of coal and blown with a fan 
 blast, bricks and a few plates being used to confine the fire (Har- 
 bord and Hall). 
 
 Retort furnaces are properly those used (in non-ferrous metal- 
 lurgy) for distilling (volatilizing) metals, etc., as in the purification 
 of zinc. They contain a chamber in which the material is heated 
 out of contact with the fuel or gases, and a flue leading to a 
 condensing (cooling) chamber; they may be similar to a muffle 
 or a crucible furnace. 
 
 Heating furnaces or reheating furnaces are those used for 
 heating solid pieces of iron or steel to a temperature suitable for 
 rolling, forging, etc. They are usually of the ordinary or regener- 
 ative reverberatory type, and the names given above are used 
 more generally for those which are built above the floor level, and 
 in which the material is charged horizontally through doors in the 
 ,side (horizontal heating furnace), as in reheating billets, slabs, 
 etc. A special type, buijt below the floor level, and charged 
 through the top (vertical heating furnace), is employed for heat- 
 ing ingots which are usually charged before they have completely 
 solidified, and hence must be kept in a vertical position to have 
 the pipe in the top. Such furnaces are called soaking pits, soak- 
 ing furnaces, or pit heating furnaces. They are generally pro- 
 vided with regenerators, but the original type (Gjers pit ; soaking 
 pit process) did not employ any fuel, the heat of the still molten 
 interior of the ingot being depended upon to bring the exterior 
 portion to the proper temperature; the action whereby the 
 heat diffuses is termed soaking. 
 
 A continuous furnace, strictly speaking, is one which is charged 
 at one end and drawn (or tapped) at the other. This, of course, 
 includes such types as the blast furnace, but is generally con- 
 sidered to mean a continuous heating furnace which is of the 
 reverberatory type, but longer than ordinary, frequently recuper- 
 ative, and used for heating billets, etc. ; these are charged cold at 
 the flue end and are moved forward over water-cooled pipes (with 
 rounds, they may simply roll down by gravity) by hydraulic 
 pushers, and are drawn at the fire-place end. 
 
 Furnace Additions. See Recarburization. 
 
 Furnace Amianthus. See Salamander. 
 
 Furnace Annealing. See page 232. 
 
 Furnace Coal. See Coal. 
 
 Furnace Coke. See page 96. 
 
 Furnace Cooling. See page 232. 
 
 Furnace Slag. See Slag. 
 
 Furnace Test. Sometimes simply test. A portion of metal taken 
 from an open hearth furnace and cooled and broken to determine 
 by the fracture the approximate amount of carbon, etc., in the 
 bath. If this is sent to the chemical laboratory, it is frequently 
 called the preliminary test. In England it is usually forged 
 down under a hammer before quenching and breaking to deter- 
 mine its freedom from red-shortness. 
 
FUSE FUSION POINT 185 
 
 Fuse. To melt; to liquefy "by the application of heat. 
 
 Fused Silica. See page 395. 
 
 Fusible Alloy. See page 4. 
 
 Fusible Cement. See page 69. 
 
 Fusible Cones. See page 209. 
 
 Fusing-point Pyrometry. See page 209. 
 
 Fusion. (i) General: see page 201; (2) zone in meteorites: see 
 page 292; (3) zone of complete fusion in blast furnace practice: 
 see page 36; (4) zone of incipient fusion in blast furnace prac- 
 tice: see page 36. 
 
 Fusion Curve. See Curve. 
 
 Fusion Point. See page 201. 
 
G. (i) Gravity, q. .; (2) gram or gramme. 
 
 Ga. Chemical symbol for gallium: see page 84. 
 
 Gd. Chemical symbol for gadolinium: see page 84. 
 
 Ge. Chemical symbol for germanium: see page 84. 
 
 Gl. Chemical symbol for glucinum (at one time called beryllium) : 
 see page 84. 
 
 G. M. V. Gram-molecular volume: see page 83. 
 
 G. M. B. Good merchantable brand (of pig iron). 
 
 G. M. W. Gram-molecular weight: see page 83. 
 
 Gag. See Hammer. 
 
 Gag Press. See Straightening Press. 
 
 Gage. (i) The thickness of a sheet or plate; (2) an instrument for 
 measuring the dimensions, etc., of an object or substance; (3) a 
 table showing the equivalents of the arbitrary markings on a 
 fixed gage. Among those of more particular interest in this con- 
 nection are the following: Limit, plus and minus, or high and low 
 gages are those provided with two measuring devices correspond- 
 ing respectively to the maximum and minimum dimensions to 
 which the object must conform; for example, in measuring a hole, 
 the minimum gage must enter, while the maximum gage must not. 
 Inside and outside gages are -to measure respectively the internal 
 and external dimensions of a hollow object. A stud gage is used 
 to determine the proper spacing of two or more holes as in splice 
 bars. For shrinkage gage, see Molding, page 296. 
 
 In the following table are given the various gages used for wire 
 and sheets or thin plates (heavier plates are recorded in fractions 
 of an inch or other unit). 
 
 "The wire gage for which sizes are shown under the title of 
 American Steel & Wire Co.'s gage, was the same as the Washburn 
 & Moen gage, and also the same as that used by practically all of 
 the steel wire manufacturers of the United States, under various 
 names. It results from this fact that there is really a standard 
 steel wire gage in the United States, although this has not been 
 formally recognized. 
 
 "Upon the recommendation of the Bureau of Standards at 
 Washington, a number of the principal wire manufacturers and 
 important consumers have agreed that it would be well to desig- 
 nate this gage as the Steel Wire Gage ; in cases where it becomes 
 necessary to distinguish it from the British Standard Wire Gage, 
 it may be called the United States Steel Wire Gage. The name 
 thus adopted has official sanction, although without legal effect. 
 
 "The only wire gage which has been recognized in Acts of 
 Congress is the Birmingham gage. The Treasury Department 
 has for many years used this gage in connection with importations 
 of wire, and the adoption of succeeding tariff acts with provisions 
 for the assessment of duty according to gage numbers gives 
 legislative sanction to the gage. 
 186 
 
GAGE 187 
 
 "Until certain provisions of the tariff act are amended, the 
 Treasury Department probably cannot discontinue the use of the 
 Birmingham gage. It should, however, be abandoned by all 
 other users, since the gage itself is radically defective, and it is 
 nearly obsolete, both in the United States and in Great Britain, 
 where it originated. 
 
 "For copper wires and wires of other metals the gage univer- 
 sally recognized in the United States is the American Wire Gage, 
 also known as the Brown & Sharpe. No confusion need arise 
 between the Steel Wire Gage and the American Wire Gage, 
 because the fields covered by the two gages are distinct and 
 definite." (From pamphlet of the American Steel & Wire Co.) 
 
 The Roebling gage is practically the same as the American 
 Steel & Wire Company's gage. The Birmingham gage is some- 
 times referred to as the English standard wire gage. The 
 Edison or circular mil gage was devised by the Edison Company 
 to simplify calculations and the ordering of round wires for 
 electrical purposes. The mil (m) is 0.001*; the circular mil 
 (c.m.) is the area of a circle with a diameter of i mil. The com- 
 parative area of a wire (or circle) in circular mils is considered 
 simply as the square of its diameter in mils. As the areas of 
 circles are to each other as the squares of their diameters, com- 
 parative results are thus secured without the trouble of working 
 
 irD z 
 out On the scale employed the number multiplied by 1000 
 
 gives the number of circular mils; thus, No. 100 is 100,000 c.m., 
 and No. 50 is 50,000 c.m.; etc. The square root of the number of 
 c.m. gives the diameter in mils; multiplying by 0.7854 will give 
 the actual area in square mils. There are also in use in this 
 country a number of screw gages, nominally the same but which 
 vary with different makers; and the piano wire gage, in which 
 the numbers increase with the diameter. To test the accuracy 
 of the openings or notches of a wire gage an instrument known as 
 a fiat gage is provided. A micrometer gage or micrometer 
 caliper has an opening regulated by a screw arrangement usually 
 reading in thousandths of an inch (or millimeter). This is the 
 type, in different sizes, most commonly used for measuring 
 thickness, particularly of plates and similar material. A special 
 form of plate gage, to measure them during rolling (while hot), is 
 provided with a handle and is operated by a spring and trigger to 
 obviate a too near approach to the hot pieces. Calipers, con- 
 sisting of two curved arms pivoted at one end are frequently used 
 for large objects, the dimensions being determined by measuring 
 on a scale the opening between points. A transfer caliper, used 
 where there is an enlargement, which would prevent withdrawing 
 the caliper without opening it, has a small arm which can be 
 adjusted to show the point at which the caliper is set when on 
 the object, so that, after opening the arms for withdrawal, 
 they may again be closed to the same point as before and the 
 opening measured. There, are various other forms specially 
 devised and named according to the purpose for which they are 
 used, such as screw thread gages, track gages, wheel gages, etc. 
 
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1 90 GAGE HOLE GAS COAL 
 
 Gage Hole. See page 507. 
 
 Gage Length ; Gaged Length. Of a test piece: see page 473. 
 
 Galbraith Furnace. See page 155. 
 
 Gallet Process.--See page 118. 
 
 Galvanic Action. Same as voltaic action. 
 
 Galvanic Process (rare). Of galvanizing: see page 370. 
 
 Galvanized Wire. See page 508. , 
 
 Galvanizing. See pages 370 and 431. 
 
 Galvanizing Pan. See page 509. 
 
 Galvanizing Pot. See page 431. 
 
 Galvanometric Method. For temperature measurements: see 
 page 208. 
 
 Galy-Cazalet Process. (i) For fluid compression: see page 63; 
 (2) for steel: see page 318. 
 
 Gamma Cementite. See page 273. 
 
 Gamma (7) Iron. See pages 264 and 272. 
 
 Gamma Iron Theory. Of hardening: see page 280. 
 
 Gamma Martensite. See page 276. 
 
 Gamma Theory. Of hardening: see page 280. 
 
 Gangue. (i) General: see Ore; (2) nature of, in iron ore: seepage 
 243- 
 
 Ganister. See page 395. 
 
 Gantry Crane. See page 32. 
 
 Garnaut and Siegfield Process. See page 233. 
 
 Gamier Process. See page 385. 
 
 Garrett Mill. See page 417. 
 
 Gartsherrie Process. Same as Alexander and M'Cosh process; 
 for the recovery of tar and ammonia from the gas of a blast fur- 
 nace using raw coal. 
 
 Garut Process. See page 503. 
 
 Gas. Matter in a state where the molecules are free to move except 
 for any external restraint. A perfect or ideal gas is one which 
 conforms to the characteristic equation of a gas: 
 
 pv = RT 
 p and v are respectively the pressure and the volume at the 
 
 given temperature; T is the absolute temperature; R is -^^- 
 
 (for centigrade degrees) or (for Fahrenheit degrees) where 
 409 
 
 po and ED are values at absolute zero for pressure and volume 
 respectively. Boyle's law (also called Mariotte's law), which 
 is not entirely true, is that the volume of a gas varies inversely 
 as the pressure, the temperature remaining constant. The 
 law of Charles (also called after Dalton and Gay-Lussac) is that 
 the volume of a gas varies directly with the absolute temperature, 
 the pressure remaining constant. Van der Waal's formula 
 expresses Boyle's law with the additional factor of molecular 
 attraction. Graham's law states that the rate of flow of a gas 
 is inversely proportional to the square root of its density. 
 
 Gas Cleaning. See page 33. 
 
 Gas Coal. See Coal. 
 
GAS COKE GIT 191 
 
 Gas Coke. See page 97. 
 
 Gas Collector. See page 61. 
 
 Gas Furnace. See page 181. 
 
 Gas Generating Furnace ; Generator. See page 362. 
 
 Gas Hammer. See Hammer. 
 
 Gas Hole. See page 55. 
 
 Gas-house Coke. See page 97. 
 
 Gas Producer. See Producer. 
 
 Gas Pyrometer. See page 207. 
 
 Gas Thermometer. See page 205. 
 
 Gas Washer. See page 33. 
 
 Gas Waste Acid. Sulphurous acid, SO 2 ; made from spent oxide 
 
 (oxide of manganese containing sulphur) from the purifiers in gas 
 
 works; it contains no arsenic. 
 Gaseous Cements. See pages 67 and 69. 
 Gaseous State. See page 81. 
 Gaseous Volumes. Law of: see page 85. 
 Gasogene (French). Gas producer. 
 
 Gasometer. A vessel or tank for holding or measuring gases. 
 Gasparin's Pyrometer. See page 207. 
 Gassed. Of a person overcome by gas at a blast furnace. 
 Gate. See page 299. 
 Gathmann Process. See page 60. 
 Gauge. See Gage. 
 Gay-Lussac's Law. See page 85. 
 Gayley Dry-blast Process. See page 30. 
 Gear Driven. See page 407. 
 General Purposes Temper. See Temper. 
 General Selective Corrosion. See page 106. 
 Generator ; Generator Gas. See page 362. 
 Gentle Aeration. See page 107. 
 Geode. See page 125. 
 Gerhardt Process. See page 141 
 German Bloomary. See page 141. 
 German Clay. See page 302. 
 German Dinas Brick. See page 395. 
 German Forge. See page 383. 
 German Forge Hammer. See Hammer. 
 German Mill. See page 417. 
 German Process. See page 75. 
 German Steel (obs.). (i) Steel (wrought iron) made either direct 
 
 from the ore (see page 141) or first into pig (see page 75); (2) 
 
 cemented iron: see page 71; (3) an old name for shear steel, q.v. 
 Gerstner's Law. See page 334. 
 Gesner Process. See page 369. 
 Ghost ; Ghost Line ; Ghost Structure. See page 289. 
 Gilchrist (P.C.) Process. See page 318. 
 Gill (Chas.) Method. Of quenching: see page 229. 
 Gillon and Dujardin Mill. See page 417. 
 Gin Furnace. See page 155. 
 Girod Furnace. See page 156. 
 Git ; Git Mold. See pages 61 and 299. 
 
IQ2 GJERS METHOD GRAM-MOLECULAR 
 
 Gjers Method. For mixing steel: by pouring it from one ladle into 
 another. 
 
 Gjers Pit. See page 184. 
 - Glance Coal. See Coal. 
 
 Glanced Sheet. See page 431. 
 
 Glass Hardness. See Hardness. 
 
 Glaze. See page 370. 
 
 Glazed Bars. See page 71. 
 
 Glazed Pig ; Glazy Iron. See page 343. 
 
 Glide Plane ; Gliding Plane. See pages 123 and 282. 
 
 Globular Pearlite. See page 2 74. 
 
 Globulite. See page 120. 
 
 Glut Weld. See page 502. 
 
 Gnathoid. See page 290. 
 
 Gobbed Heat See page 377. 
 
 Gobbing Up. See page 35. 
 
 Goethite. See page 244. 
 
 Goldschmidt Process. A method for producing metals by reduc- 
 tion with aluminum. The ore or oxide of the metal and metallic 
 aluminum, both in a finely granular condition, are mixed together 
 (this mixture is called thermit), and the reaction started by ignit- 
 ing a small quantity of magnesium powder or ribbon, etc., called 
 the starter, placed on top of the charge. The reaction then pro- 
 ceeds with considerable violence and the resulting metal is at a 
 high temperature. The process is used for obtaining carbonless 
 metals and alloys; the metal, on account of its high temperature 
 is also employed for repairing broken pieces of machinery, and 
 the hot slag produced is also used for heating the ends of tubes, 
 etc., which are to be welded together. 
 
 Goniometer. See page 119. 
 
 Gore's Phenomenon. See page 265. 
 
 Gossan. See page 245. 
 
 Gothic Pass ; Groove. See page 405. 
 
 Gozzan. See page 245. 
 
 Grade. Of steel: see page 455. 
 
 Gradual Cement. See page 67. 
 
 Graduated. Of a measuring tube or vessel which is marked off with 
 fine lines to show proportional volumes; such a vessel is called 
 a graduate. 
 
 Graff Process. See page 141. 
 
 Graham's Law. See Gas. 
 
 Grain. See page 122. 
 
 Grain of First Order. See page 127. 
 
 Grain Growth. (i)General: see page 213; (2) as affected by strain: 
 see page 216. 
 
 Grain Refining. See pages 212 and 232. 
 
 Grain Roll. See page 403. 
 
 Grain of Second Order. See page 127. 
 
 Grain Size. See page 213. 
 
 Gram Calorie. See page 199. 
 
 Gram-centigrade Heat Unit. See page 199. 
 
 Gram-molecular Volume. See page 83. 
 
GRAM-MOLECULARGREGORY 1 93 
 
 Gram-molecular Weight. See page 83. 
 
 Grampus. See page 135. 
 
 Granitoid Structure. See page 125. 
 
 Granular. See page 122. 
 
 Granular -crystalline Fracture. See page 1 78. 
 
 Granular Eutectic. See page 269. 
 
 Granular Fracture. See page 1 78. 
 
 Granular Iron. Bar (wrought) iron which shows a granular frac- 
 ture due to the absence of cinder, and is" therefore a guarantee of its 
 strength and purity (Horner). 
 
 Granular Pearlite. See page 274. 
 
 Granulated Iron. Pig iron reduced to the size of shot by pouring 
 the molten metal into water. 
 
 Granulation. See page 121. 
 
 Granulation Range ; Zone. See page 121. 
 
 Granule; GranuUtic. See page 122. 
 
 Granulitic Structure. See page 125. 
 
 Graph. See Curve. 
 
 Graphic Formula. See page 86. 
 
 Graphite. (i) Form of carbon: see page 50; (2) constituent of 
 iron: see page 277; (3) a refractory: see page 398. 
 
 Graphite Blacking. See page 298. 
 
 Graphite Crucible. See page in. 
 
 Graphitic Carbon. See Graphite. 
 
 Graphitic Corrosion. See page 106. 
 
 Graphitic Pig. See page 342. 
 
 Graphitic Silicon. See Silicon. 
 
 Graphitiferous. Containing graphite. 
 
 Graphitite. See Carbon. 
 
 Sraphitization. See pages 106 and 278. 
 
 Graphitization of Cementite. See page 278. 
 
 Graphitoid ; Graphitoidal. See Carbon. 
 
 Graphitoidal Pig Iron. Graphitic pig iron; in which practically all 
 the carbon is in the graphitic form. 
 
 Graphitoidal Silicon. See Silicon. 
 
 Grate Bars. The bars across a fireplace which support the fuel. 
 
 Gray Body. See page 207. 
 
 Gray Cast Iron ; Forge Iron. See page 342. 
 
 Gray-granular Fracture. See page 178. 
 
 Gray Iron ; Pig. See page 342. 
 
 Grease Pan ; Pot. See page 432. 
 
 Greater Calorie. See page 199. 
 
 Greatest Principal Stress. See page 332. 
 
 Green. Unused or raw; untreated or incompletely treated. 
 
 Green Brick. See page 395. 
 
 Green Coal. See Coal. 
 
 Green Fire. See page 203. 
 
 Green Ingot. See page 57. 
 
 Green Sand ; Green Sand Molding. See page 296. 
 
 Green Vitriol. Commercial sulphate of iron. 
 
 Greenawalt Process. See page 45. 
 
 Gregory and Green Process. See page 386. 
 
 13 
 
1 94 GRENET'S SERIES GUTTER 
 
 Grenet's Series of Salts. To determine temperatures: see page 
 209. 
 
 Grey Mill. See page 417. 
 
 Gridiron Twinning. See page 124. 
 
 Grinding. (i) Preparing smooth surfaces by abrasion; (2) reduc- 
 ing a substance to a fine state of division. 
 
 Grips. Of a testing machine: see page 469. 
 
 Gripper. In wire drawing: see page 508. 
 
 Grog (Eng.) See page 396. 
 
 Grb'ndal Furnace. See page 156. 
 
 Grondal-Kjellin Furnace. See page 156. 
 
 Grondal Process. See page 44. 
 
 Gronwall Furnace. See page 157. 
 
 Gronwall, Lindblad and Stalhane Furnace. See page 157. 
 
 Groove ; Grooved Roll. See page 404. 
 
 Gross Ton. See Ton. 
 
 Ground Mass. See page 125. 
 
 Group Casting. See pages 61 and 299. 
 
 Growth of Crystals. See pages 120 and 213. 
 
 Grundy. Granulated pig iron (Raymond). 
 
 Gruson's Chilled Cast Iron Armor. See page 9. 
 Guard. See page 415. 
 
 Guard Plate. See page 32. 
 
 Gubbin. A kind of ironstone (Raymond). 
 
 Guenyveau Process. See page 380. 
 
 Guest Process. See page 380. 
 
 Guide ; Guide Mill ; Guide Roll. See page 415. 
 
 Guillaume's Invar. See page 451. 
 
 Guillery's Method. For determining hardness: see page 478. 
 
 Guillef s Theory. (i) Of hardening: see page 280; (2) of ternary 
 steels: see page 443. 
 
 Guillotine Shears. See page 412. 
 
 Guit. See page 299. 
 
 Gun. For a blast furnace: see page 37. 
 
 Gun Iron ; Metal. See page 343. 
 
 Gun Screw Wire. See page 509. 
 
 Gunther Process. See page 141. 
 
 Gurlt Process. See page 141. 
 
 Gusy (Eng.). Of steel, wild. 
 
 Guthrie's Cryohydrate. See page 266. 
 
 Gutowsky's Diagram. See page 272. 
 
 Gutter. (i) Spout; (2) the name sometimes given to the runner of 
 a blast furnace. 
 
H 
 
 H. Chemical symbol for hydrogen, q.v. 
 
 He. Chemical symbol for helium: see page 84. 
 
 Hg. Chemical symbol for mercury (Latin, hydrargyrum) : see page 
 84. 
 
 Ho. Chemical symbol for holmium: see page 84. 
 
 H.J. Hot junction (of a couple): see page 209. 
 
 H.R.P. & L. Hot rolled, pickled and limed (of strips, bars, etc.). 
 
 Hackly Fracture. See page 1 78. 
 
 Had field's Manganese Steel. See page 451. 
 
 Hadfield Process. (i) For reduction: heating the oxide of a metal 
 with granulated aluminum and a little fluorspar in a crucible; 
 (2) for sound ingots: see page 60. 
 
 Haematite (Eng 1 .). Hematite, q.v. 
 
 Hainsworth Process. See page 60. 
 
 Hair Crack. See Seam. 
 
 Hair Plate. See page 135. 
 
 Hair Seam. See Seam. 
 
 Halberger Furnace. See page 158. 
 
 Half-chamotte Brick. See page 396. 
 
 Half-cup Fracture. See page 179. 
 
 Half Roll. See page 404. 
 
 Half-silica Brick. See page 396. 
 
 Hammer. Of a drop test machine: see page 481. 
 
 Hammer. A device for forging or reducing the section of a piece 
 of -metal, or changing the shape, consisting essentially of a mass 
 of metal, the hammer proper (hammer head or tup), which falls 
 .or is driven violently against the piece to be acted upon. The 
 face of the hammer is usually removable and is called the hammer 
 block or die (particularly the latter if of a special section; this 
 also applies to the anvil block). The piece is supported on a 
 heavy mass of metal, the anvil, generally of cast iron or steel, to 
 render the blow effective. If the face is removable it is called the 
 anvil block. A working anvil block (Eng.) is a block of steel or 
 cast iron fitting on the top of the anvil block. A false-block is 
 usually a casting inserted between the. anvil block and the bottom 
 die of a steam hammer to raise the die to the proper height. A 
 projecting dovetail on the lower face of the false-block is keyed 
 into a recess in the anvil block, while a recess on its top face 
 receives the dovetail projecting from the bottom surface of the 
 bottom die. Its only purpose is to save weight in the bottom die. 
 When this is to be changed often, as in shape or swage work, it 
 is undesirable to have it as heavy and cumbersome as would be 
 necessary were the die keyed directly into the anvil block (G. 
 Aertsen). Hammers light enough are worked by hand (hand 
 hammer, sledge), but those of any considerable weight are oper- 
 ated by power, usually steam, rarely water. They may be classi- 
 fied according to the source of power, into: 
 
196 
 
 HAMMER 
 
 I. Water: 
 
 i. Indirect: Helve. 
 
 II. Steam: 
 
 1. Indirect: Helve. 
 
 2. Direct: Ordinary steam hammer: 
 
 (a) Single-acting. 
 
 (b) Double-acting. 
 
 III. Gas: Direct. 
 
 Steam hammers consist of an anvil, and the hammer proper 
 fastened to one end of a rod, the other end being connected to a 
 piston which travels in a steam cylinder. If steam is admitted 
 to only one side of the piston, simply to raise the hammer which 
 falls by gravity, it is single-acting ; if steam is also used to drive 
 the hammer down and so increase the force of the blow, double- 
 acting. In either case the hammer is always rated according to 
 
 FIG. 23. Steam hammer. 
 (Thurston, "Iron and Steel.") 
 
 the weight of the tup. A helve (crocodile hammer, lift hammer, 
 tilt hammer, trip hammer, fly hammer, German forge hammer) 
 
 is a hammer operated on the principle of a lever, the tup falling 
 by gravity. The tup is attached to a bar or handle of wood or 
 iron, working on a pivot or fulcrum. The actuating mechanism 
 consists of a wheel or shaft driven by water (water helve, battery) 
 or by steam (steam helve), provided with cams or teeth. De- 
 
HAMMER HARD SPOTS 197 
 
 pending upon the general arrangement, various names are as- 
 signed: If the power is applied at one end, the pivot being at 
 the other, and the tup intermediate, it is called a nose helve, 
 frontal helve, or T hammer; if the force acts in the middle, a 
 belly helve ; while if the pivot is in the middle, a tail helve. 
 When not in use the helve is supported by a wooden prop or gag. 
 A drop hammer is one which is allowed to fall by gravity, being 
 attached to a belt which passes over a pulley supplying the 
 necessary power for raising it. A cogging hammer is one used for 
 reducing ingots to blooms. A plating hammer (obs.) was for- 
 merly used in the manufacture of plates or sheets. A gas ham- 
 mer is operated on the same principle as a gas engine. A raising 
 hammer (Eng.) is a term sometimes employed for a hammer used 
 for forming or cupping sheets, having a long rounded head. See 
 also Forging. 
 
 Hammer Block. See Hammer. 
 
 Hammer Dressing. See Forging. 
 
 Hammer Forging. See Forging. 
 
 Hammer Hardness. See Hardness. 
 
 Hammer Head.-^See Hammer. 
 
 Hammer Refining. See Mechanical Refining. 
 
 Hammer Scale. See Scale. 
 
 Hammer Slag. See Slag. 
 
 Hammer Test. See page 476. 
 
 Hammered Weld. See page 501. 
 
 Hamoir Process. See page 386. 
 
 Hampton Process. See page 9. 
 
 Hand Guide Mill. See page 416. 
 
 Hand Hammer. See Hammer. 
 
 Hand Mill. See page 416. 
 
 Hanging. Of a blast furnace: see page 35. 
 
 Hanging Guard. See page 415. 
 
 Hanging Test. See page 469. 
 
 Hank. See Coil. 
 
 Hannover Process. See Alloy. 
 
 Harbord Process. See page 30. 
 
 Hards. See Slag. 
 
 Hard Blow. See page 21. 
 
 Hard Castings. Malleable castings: see page 257. 
 
 Hard Center. The effect produced usually by too rapid heating, so 
 that the inside of a piece of metal is insufficiently heated, and 
 consequently is worked at too low a temperature; rarely caused 
 by segregation. 
 
 Hard-centered Steel. See page 64. 
 
 Hard Coal. See Coal. 
 
 Hard Solder. See page 505. 
 
 Hard Spots. Spots or streaks in steel which are harder than the 
 body of the metal. This is generally observed when material is 
 machined. They are of infrequent occurrence and may be due 
 to segregation (segregated spot) or to imperfect mixing of the 
 manganese addition (manganese spot). Soft spots are just the 
 
1 98 HARD STEEL HARDNESS TESTS 
 
 opposite, due to absence of carbon and manganese, probably on 
 account of some local oxidizing action. 
 
 Hard Steel. See page 455. 
 
 Hard Tap. In tapping a furnace, when the tapping hole is opened 
 up only with difficulty. 
 
 Hardened Castings (rare). See page 58. 
 
 Hardener. The name sometimes used for foundry iron high in 
 manganese, or for the manganese itself. 
 
 Hardening. Bringing material to the condition in which it is best 
 able to resist indentation, abrasion or scratching. There are two 
 general methods for accomplishing this: (a) heating to a suffi- 
 ciently high temperature and then cooling rapidly (this applies 
 only to steel or iron alloys: see Heat Treatment), and (b) by 
 cold mechanical working. The Dean process was designed to 
 harden and strengthen the bore of guns, etc. It consisted in 
 forcing through them a succession of tapered steel cylinders, each 
 slightly larger than the preceding. It was stated to have been 
 used successfully for bronze guns, but that it did not diminish the 
 erosion of steel guns. 
 
 Hardening Carbide. See page 276. 
 
 Hardening Carbon. See pages 276 and 278. 
 
 Hardening Carbon Theory. Of hardening: see page 280. 
 
 Hardening Effect. Of permanent set: see page 334. 
 
 Hardening on a Falling Heat. See page 229. 
 
 Hardening Phosphorus. See Phosphorus. 
 
 Hardening Quenching. See page 228. 
 
 Hardening by Reheating. See page 279. 
 
 Hardening on a Rising Heat. See page 228. 
 
 Hardening, Special Methods of. See page 229. 
 
 Hardening by Subcooling. See page 279. 
 
 Hardening Theories. See pages 279 and 280. 
 
 Hardening by Overstraining. See page 279. 
 
 Hardenite. (i) Constituent of steel: see page 275; (2) Caron's 
 cement: see page 68. 
 
 Hardite. See page 278. 
 
 Hardness. The resistance offered by a body to abrasion or pene- 
 tration. (For methods for determining relative hardness, see 
 Testing.) The hardness of steel is sometimes called its temper, 
 and to draw the temper means to anneal. Natural hardness is 
 the hardness of material as ordinarily made, without any special 
 additional treatment. - Glass hardness is the highest degree of 
 hardness attainable by steel, in which condition it can scratch 
 glass; but as the hardness of glass may vary, it has been suggested 
 that flint hardness be substituted. Hammer hardness (or 
 rolling hardness) is the effect produced when heated metal is 
 worked below its critical temperature; if this reaches a tempera- 
 ture corresponding to a blue temper color (blue working), the 
 metal may be rendered brittle, in this case called blue -shortness : 
 see also page 331. 
 
 Hardness Number. See page 477. 
 
 Hardness Tests. See page 477. 
 
HARMET PROCESS HEAT 1 99 
 
 Harmet Process. (i) Fluid compression: see page 64; (2) electric 
 furnace: see page 158; (3) basic Bessemer: see page 21. 
 
 Harvey Process. (i) Carburizing: see page 9; (2) direct: see 
 page 141. 
 
 Hatton Converter. See page 24. 
 
 Hawkins Process. See page 141. 
 
 Hay Band ; Rope. See page 299. 
 
 Haythorne Process. See page 385. 
 
 Head ; Head Metal. See page 56. 
 
 Head Squeezer. See page 377. 
 
 Header. See page 56. 
 
 Healing. Where cracks are formed in an ingot during'the first'few 
 passes in rolling it down, which are later welded up if the tempera- 
 ture is high enough and the metal is sufficiently soft (low in 
 carbon). 
 
 Heap. See page 181. 
 
 Heart. Core: see page 67. 
 
 Hearth. (i) Of a blastfurnace: see page 27; (2) charcoal hearth: 
 see page 75; (3) furnace: seepage 182; (4) of an open hearth fur- 
 nace: see page 310. 
 
 Hearth Fining ; Refining. : See page 382. 
 
 Heat. A form of energy (heat energy) due to molecular motion 
 (dynamic theory of heat.) It was at one time believed that heat 
 was an actual substance called caloric. Two kinds of heat are 
 recognized: sensible and latent. Sensible heat or thermome- 
 tric heat is the degree of heat which a body possesses, commonly 
 known as its temperature. The measurement of ordinary or 
 relatively low temperatures is performed by instruments called 
 thermometers, and of high temperatures by pyrometers (see 
 below). 
 
 Latent heat is the amount liberated or absorbed due to an in- 
 ternal or molecular change occurring in a body at constant tem- 
 perature. There are three causes for this spontaneous liberation 
 (evolution) or absorption of heat: (a) formation or dissociation of 
 chemical compounds; (6) changes of state; (c) allotropic or poly- 
 morphic transformations. The amount of heat is measured in 
 heat units or thermal units which are based on either the metric 
 or the English system. In the metric system the calorie (some- 
 times spelled calory ; also called kilogram-centigrade heat unit, 
 large calorie, kilogram calorie, greater calorie, major calorie, 
 French calorie, or true calorie) is the amount of heat required to 
 raise i kg. of water through i C.; the zero calorie is where the 
 water is raised from o to i C.; the common calorie where the 
 water is raised from 15 to 16 C.; and the mean calorie the one- 
 hundredth part of the amount of heat necessary to raise the 
 kilogram of water from o to 100 C. The small calorie (gram- 
 centigrade heat unit, gram calorie, minor calorie or lesser calorie) 
 is the heat required to raise i gram of water 'through i C., 
 hence is the one-thousandth part of the calorie. The British 
 thermal unit (B.T.U.) is the amount of heat required to raise 
 the^temperature of i Ib. (avr.) of water through i F., usually at 
 ordinary temperatures from say 65 to 66 F., sometimes from 32 
 
200 HEAT 
 
 to 33 F. A hybrid unit rarely employed is the pound calorie 
 (pound-centigrade heat unit) which is the amount of heat 
 required to raise the temperature of i Ib. of water through i C. 
 For purposes of conversion: i cal. = 3.968 B.T.U.; i B.T.U. = 
 
 0.252 cal.; i Ib. cal. = B.T.U. = 0.4536 cal. 
 
 Heat may be transmitted in one or more of three ways, by 
 
 1. Conduction: the heat traveling through a solid body one 
 end of which is connected directly with the source of heat; molecu- 
 lar transference. 
 
 2. Convection: by currents (transference) of the actual 
 particles of a gas or liquid. 
 
 3. Radiation: by heat waves emanating from the source of 
 heat and not affected by the medium through which they pass; 
 also termed radiant energy or radiant heat. Thermal conduc- 
 tivity is used to distinguish it from electrical conductivity, etc., 
 also for the relative property of a given body or the amount of 
 heat passing through a unit plate when the opposite sides have a 
 difference of i of temperature; thermometric conductivity 
 is the thermal conductivity with a unit 1 of "heat sufficient to 
 raise a unit volume one degree" (Std. Diet.). Newton's law of 
 radiation (or of cooling) is that "the amount of heat radiated from 
 one body to another in a unit time is a direct function of the 
 difference in temperature of the two bodies." Emissivity or 
 external conductivity is the rate at which a body radiates heat. 
 Dulong and Petit found that the rate of radiation depended only 
 on the nature of the surface and on the temperature of a body 
 and of its surroundings and not on its shape; that convection 
 depended on the temperature of a body and of its surroundings 
 and upon its shape and position, but not on the nature of its 
 surface (Langmuir). Langmuir's film theory is that around 
 each surface there is a small volume of gas through which heat 
 passes mainly by conduction. The term surface resistance refers 
 to resistance, offered by the surface itself irrespective of the mate- 
 rial, to loss of heat from furnaces, etc., while thermal resistance 
 refers to the material itself irrespective of the surface. A radia- 
 tion curve, showing the rate of cooling of a body, is the same as a 
 cooling curve. Prevost's law, also known as the law of exchanges, 
 is that all bodies above absolute zero radiate heat, the amount 
 being dependent only upon the absolute temperature; of two 
 adjacent bodies at different temperatures, the one at the lower 
 temperature receives more than it emits; if at the same tempera- 
 ture, the exchange is equal but does not cease. 
 
 A process in which heat is liberated is known as an exothermic 
 reaction ; one in which it is absorbed, an endothermic reaction. 
 A body responsible for an exothermic reaction is sometimes termed 
 a refrigerating agent or refrigerant ; in the case of an endo- 
 thermic reaction, a calorific agent. The amount of heat liberated 
 or absorbed when a chemical compound is formed is called the 
 heat of formation. Hess's law, forming the foundation of 
 thermo-chemistry, is that in any chemical action the amount of 
 
HEAT 201 
 
 heat liberated is independent of whether the action is continuous 
 or interrupted. The law of constant heat sums is that in any 
 chemical change the amount of heat is not dependent on the 
 order or nature of changes, but only on the final result. The 
 law of thermoneutrality is that if dilute solutions of neutral salts 
 are mixed and no precipitation occurs, no thermal change is 
 involved. 
 
 Calorimetry is the determination of the total heat units in a 
 body or involved in a given reaction or transformation. The 
 measurement of heat liberated or absorbed is determined by 
 means of an instrument called a calorimeter, in which the given 
 determination is made, e.g., when fuel is burned (heat of combus- 
 tion), the value being usually obtained from the increase or 
 decrease in the temperature of a definite weight of water. Calo- 
 rimeters on this principle have been devised by Berthelot, 
 Siemens, and White. Specific heat (thermal capacity) is the 
 ratio between the amounts of heat required to raise the tempera- 
 ture of a unit weight of a substance and of water i degree (either 
 Centigrade or Fahrenheit). This may be determined for a given 
 substance by mixing a known weight at a certain temperature 
 with a known weight of water at a different temperature and 
 calculating from the temperature of the mixture; this is called 
 the method of mixtures. If the mixture evolves heat (as when 
 sulphuric acid and water are mixed) this method cannot be used, 
 but the result may be secured by the method of cooling which 
 consists in comparing the time required for cooling of the same 
 weights of water and of the substance through the same range 
 of temperature under identical conditions. The water equiva- 
 lent of a substance is its weight multiplied by it's specific heat. 
 The molecular heat of a substance is its specific heat multiplied 
 by its molecular weight. The heat weight is the amount of heat 
 in a body divided by its absolute temperature. The heat of 
 solution is the amount of heat, either positive or negative respec- 
 tively, when heat is liberated or absorbed when a body goes into 
 solution. When an acid is neutralized by an equivalent weight 
 of a base, or vice versa, the heat liberated is called the heat of 
 neutralization. The heat of ionization is the difference in the 
 amount of heat when the body is undissociated (neutral) and 
 when ionized. 
 
 Fusion or melting is the conversion of a solid into a liquid. 
 The water of crystallization of certain salts may be sufficient 
 to dissolve them when heated; this is really a case of solution, 
 but is sometimes termed aqueous, aqueo -igneous, hydrothermal, 
 or watery fusion ; true fusion, where heat alone is responsible 
 for the change of state, is then termed igneous or dry fusion. 
 The heat absorbed in the conversion is called the heat of fusion 
 or more specifically the latent heat of fusion. The temperature 
 at which this change occurs is the fusion point or melting point 
 (on cooling, the freezing or solidification point). If there is no 
 well-defined temperature, the change extending over a range, it 
 is sometimes known as vitreous fusion. A fused substance above 
 (usually considerably above) its melting point is sometimes 
 
202 HEAT 
 
 referred to as supermolten. If under given conditions of tem- 
 perature and pressure a body may exist simultaneously as a liquid 
 and a gas, the latter is termed a vapor and its formation from the 
 exposed surface of the liquid is called evaporation or vaporization ; 
 the heat absorbed in the process is the heat of vaporization or 
 latent heat of vaporization ; if under the given conditions no more 
 vapor can be formed it is said to be saturated. If the evolution of 
 the vapor occurs throughout the liquid, thereby stirring it up and 
 disturbing the surface, the process is called ebullition or boiling, 
 and the minimum temperature at which this can occur, the boil- 
 ing point. The heat consumed in changing a liquid into a vapor is 
 converted into two kinds of energy; that which causes a separa- 
 tion of the particles (heat of disgregation, and that which over- 
 comes the external pressure- in increasing the volume (heat of 
 expansion). The total heat (sensible plus latent) is that required 
 to bring a liquid from the melting point and change it into 
 saturated vapor. Superheating, as a general term, signifies 
 heating above a critical point, e.g., superheated steam is steam 
 heated above the point of vaporization (the boiling point). 
 Where a liquid is converted by heat into vapor which is led into 
 another cold vessel and there condensed, the process is termed 
 distillation ; where a solid changes into a vapor (and back again 
 into a solid) without passing through an intermediate liquid state, 
 the process is termed sublimation. 
 
 Combustion is oxidation accompanied by the evolution of 
 light and heat. In its commonly accepted sense, it is the oxida- 
 tion or burning of carbon and hydrogen, either free or combined; 
 it is also applied at times to the oxidation of impurities or con- 
 stituents in some refining process. Ignition is frequently used 
 in the same sense as combustion; it is also employed to indicate 
 heating to incandescence, resulting also in the burning and driv- 
 ing off of any combustible and volatile matter, as in the case of 
 chemical precipitates. Before combustion can take place, 
 each fuel must be heated to a certain definite temperature known 
 as its ignition point, and, depending upon whether the tempera- 
 ture of combustion does or does not exceed this, it is continuous, 
 or non-continuous (discontinuous) combustion. In the case of 
 liquid fuels (oils), a combustible vapor is given off at a tempera- 
 ture below the ignition point, and this temperature is called the 
 flash point. If the action is very feeble, the combustion is said to 
 be slow or incipient ; while if energetic, it is called rapid or active. 
 Spontaneous combustion is the result of oxidation of a substance 
 by the air at ordinary temperatures, where the heat is not removed 
 as rapidly as formed, so that finally the temperature of the 
 substance reaches the ignition point. The products of com- 
 bustion (waste gases or fire gases) are the gases resulting when 
 a fuel is burned, and do not include any solid residue or ashes. 
 When the waste gases and the ashes contain no combustible 
 substance, the combustion is complete ; otherwise incomplete. 
 Retarded combustion, as in the manufacture of producer gas, is a 
 case of incomplete combustion. Smoke is produced when the 
 waste gases contain fine particles of unconsumed carbonaceous 
 
HEAT 203 
 
 matter as a result of incomplete combustion; a green fire is one 
 which is smoky hence has a tendency to be reducing. Flame js 
 the phenomenon occurring when combustible gases are formed 
 during combustion, and the luminosity depends upon the tem- 
 perature of the flame, the density of the gases, and the presence 
 of solid incandescent particles, principally the last. Dulong's 
 law for carbonaceous and hydro-carbonaceous fuels, which is 
 only approximately correct, is that the heat generated in their 
 combustion is equal to the sums of the heat of the carbon and 
 hydrogen separately, less an amount of the latter element in the 
 proportion necessary to form water with any oxygen present. 
 
 C. P. = 8o8oC + 3 4,462(H-^) 
 
 C. P. = calorific power in calories; C, H, and O the weights in 
 kilograms respectively of carbon, hydrogen, and oxygen. 
 
 "If an explosive gaseous mixture is either ignited on or forced 
 through the interstices of a porous, refractory, incandescent solid 
 . under certain conditions, a greatly accelerated combustion takes 
 place within the interstices or pores, or in other words, within 
 the boundary layers between the gaseous and solid phases 
 whenever these may be in contact and the heat developed by 
 this intensified combustion maintains the surface in a state of in- 
 candescence without any development of flame. Such conditions 
 realize my conception of flameless, incandescent, surface com- 
 bustion as a means of greatly increasing the general efficiency of 
 industrial heating operations whenever it can be conveniently 
 applied." (W. A. Bone, abs. in Iron Age, Dec. 7, 1911, 1248+.) 
 
 The amount of heat (number of heat units) produced when a 
 unit weight of a substance burns is called the calorific power 
 (C. P.) or heat of combustion and always has the same value irre- 
 spective of the rate of combustion (i.e., the time occupied). The 
 resulting temperature is called the calorific intensity (C. I.) or 
 pyrometer effect (rare), or temperature of combustion, which 
 varies according to the rate of combustion and other conditions, 
 such as the presence or absence of diluting substances (e.g., nitro- 
 gen), and the initial temperature. The calorific power of fuels is 
 sometimes measured by the weight of water at a given temperature 
 evaporated by a unit weight of the fuel; this is called the evapora- 
 tive power. 
 
 Regeneration is a method for preheating air or fuel gas to 
 obtain a higher temperature of combustion, or greater economy 
 in fuel. To effect this there are provided two or more set of flues 
 (regenerators ; regenerative chambers) which are filled with 
 checker work (checkers), i.e., fire-bricks laid in such a way that 
 small passages are left. The products of combustion are passed 
 through one set for a certain period, their heat being absorbed in 
 great part by the checker work, after which the air (or air and gas 
 separately) are passed through in the opposite direction, before 
 entering the furnace, the products of combustion then heating 
 another set. In heating blast in a stove, or removing the heat 
 from blast furnace gas in a washer, for example, application is 
 
204 HEAT 
 
 usually made of the counter-current principle. This is to bring 
 
 .the two substances together so there is always as much difference 
 
 - in temperature as possible between them so that there will be the 
 
 greatest total transfer of heat. For example with the blast stove, 
 
 the hearth or chamber where the gases burn is the hottest part 
 
 and the coolest part is at the stack; the cold blast should enter 
 
 near the stack and leave through the hearth. 
 
 Recuperation is also a system for preheating gases (usually only 
 the air): the products of combustion are caused to pass around 
 and heat iron pipes through which the air for combustion is con- 
 veyed to the furnace. 
 
 The mechanical equivalent of heat is the value for converting 
 . heat units into mechanical units (or vice versa} : 
 iB.T.U. = 778 foot-pounds, 
 i kg. cal. = 426.9 kilogrammeters. 
 
 Except in certain cases when undergoing critical changes, such 
 as the melting of ice (or the reverse, when water freezes), bodies 
 expand when heated and contract when cooled (i.e., when heat is 
 removed). The degree of expansion (or contraction) usually 
 varies at different temperatures and in different substances, and 
 is generally expressed as a proportion of the length at a standard 
 temperature (commonly o C. or 32 F). This is termed the 
 coefficient or factor of expansion and the range of temperature 
 for which it is correct (or approximately true) should be stated. 
 
 If a substance is altered by heat it is said to be thermolabile ; 
 particularly where decomposition results it is pyrolytic (pyrolysis) ; 
 if unchanged thermostable or (particularly in the sense of being 
 non-conductive) refractory. A body, such as a Welsbach man- 
 tle, which glows when heated is said to be pyrognomic ; one 
 which burns spontaneously, upon contact with air or moisture, 
 pyrophoric. 
 
 Temperature Measurement. The temperature of a body is the 
 degree of sensibile heat which it possesses, and is an indication 
 of its ability to impart heat to or receive heat from an adjacent 
 body which is respectively at a lower or a higher temperature. 
 It is stated in degrees of a scale (thermometric or pyrometric 
 scale) based on certain fixed points, such as melting points 
 or boiling points, of various substances taken as standards of 
 reference. There are two scales in common use, the Fahrenheit 
 (English) scale (F), and the Centigrade (Celsius or metric) 
 scale (C), and a third, the Reaumur scale (R), which is occasion- 
 ally encountered; these compare with each other as follows: 
 
 C F R 
 
 B. P. Water 100 212 80 
 
 M. P. ice o 32 o 
 
 Difference 100 180 80 
 
 Ratio 5 9 4 
 
 For conversion from one to another: 
 C = %(F - 32) = MR- 
 F = %C + 32 = %R + 32. 
 - 32) = %C. 
 
205 
 
 C F C F C F C F C F 
 
 300-i 
 
 =^572 600 n 
 
 ^1112 900-1 
 
 -1652 1200-n 
 
 ^2192 ISOO-i 
 
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 70 
 
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 80 
 
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 ~80 80- 
 
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 500 60- 
 
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 -1500 
 
 -40 
 
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 400 
 
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 r 60 ' 80- 
 
 r900 80- 
 
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 60 - 
 
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 300 50- 
 
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 20 50 
 
 
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 -1900 40 ~ 
 
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 -800 
 
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 80 
 
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 - 50 700- 
 
 _ 90 1000 
 
 = 30 1300- 
 
 -70 
 
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 r 50 
 
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 -1800 80 J 
 
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 -2300 
 
 
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 -1200 50 - 
 
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 -2200 
 
 
 
 32 . 300- 
 
 
 
 ir-1652 1200-J 
 
 &2192 
 
 C F C "F C ~~F C FC 'F 
 
 PIG. 24. Conversion scale for Centigrade and Fahrenheit tem- 
 peratures. (Tiemann, T. A. I. M. E., 1915.) 
 
206 HEAT 
 
 De Lisle 's scale assigns 150 degrees to the range from the 
 melting point of ice to the boiling point of water. The abso- 
 lute scale is based on absolute zero which is generally defined 
 as the temperature at which all molecular motion ceases. It 
 corresponds ^ to ^273 C. or 459-4 F., and was arrived at 
 from a consideration of the effect of temperature on the volume 
 of a perfect gas; in calculations, particularly those relating to 
 gases, these values are added to ordinary temperatures, giving 
 absolute temperatures. In honor of Lord Kelvin it has been 
 proposed to designate absolute temperatures in centigrade units 
 as degrees K. A normal scale is one based on rigorously defined 
 points and prescribed methods of determination. Particularly 
 in connection with the heating and cooling of bodies it has been 
 suggested that the letters C and R be prefixed to indicate whether 
 the temperature was falling or rising respectively, thus 
 
 C 750 C.: falling temperature. 
 R 827 C.: rising temperature. 
 
 The measurement of temperatures is termed thermometry or 
 pyrometry. The instruments by which temperatures are deter- 
 mined are usually roughly distinguished as thermometers for 
 ordinary or moderate temperatures, and pyrometers for high 
 temperatures, although these names may be used more or less 
 interchangeably. An instrument for measuring temperatures by 
 radiation is termed a radiometer (microradiometer or radio - 
 micrometer) ; particularly for losses due to radiation, a thermo- 
 radiometer. A thermoscope is an instrument for showing 
 differences or changes in temperature without, necessarily, great 
 accuracy; a differential thermoscope, one for indicating the rela- 
 tive condition of two bodies. A recording thermometer is 
 sometimes termed a thermograph or thermometrograph. 
 
 Thermomete'rs depend upon the nearly uniform expansion or 
 contraction when various substances are heated or cooled, some- 
 times referred to as a mechanical thermometer or expansion 
 pyrometer. The kind most commonly met with is a suitably 
 graduated glass tube containing mercury (mercury or mercurial 
 thermometer) ; by employing a gas, such as nitrogen, the pressure 
 of which prevents boiling at the normal temperature of about 
 356 C. (673 F.), it may be used for temperatures up to about 
 550 C. (1020 F.) for high-range mercury thermometers (Bur- 
 gess, 362). Other forms for special purposes may employ ethyl 
 alcohol or ether (spirit thermometer), or air or other gas (air ther- 
 mometer, gas thermometer) . Gas thermometers may be either 
 constant volume (variable pressure) thermometers, where the 
 volume and mass are maintained constant, or constant pressure 
 (variable volume) thermometers, where the mass of gas varies 
 but its pressure and volume remain the same. A normal ther- 
 mometer is one based on a normal scale (see above) . A metallic 
 (bimetallic or differential) thermometer depends on the different 
 degrees of expansion and contraction of two pieces of different 
 metals connected together. A chromatic thermometer is based 
 
HEAT 207 
 
 on the different colors, due to internal strains, when polarized light 
 is passed through a piece of glass, one edge of which rests on a 
 heated body. 
 
 The following classification of pyrometers is largely taken from 
 Burgess' "Measurement of High Temperatures:" 
 
 1. Gas pyrometer (Pouillet, Becquerel's volumetric or volu- 
 menometric thermometer, Sainte-Claire-Deville, Barus, Chap- 
 puis, Holborn, Callendar, Day): "Utilizes the measurement of 
 change in pressure of a gaseous mass kept at constant volume. 
 Its great volume and its fragility render it unsuitable for ordi- 
 nary measurements; it serves only to give the definition of tem- 
 perature and should only be used to standardize other pyro- 
 meters (pp. 9-10). Industrial types have been devised by 
 Bristol and Wiborgh. 
 
 2. Calorimetric pyrometer, specific heat pyrometer, water 
 pyrometer, hydropyrometer (Regnault, Violle, Le Chatelier, 
 Siemens): "Utilizes the total heat of metals, platinum in the 
 laboratory and nickel in industrial works. It is to be recom- 
 mended for intermittent researches in industrial establishments 
 because its employment demands almost no apprenticeship and 
 because the cost of installation is not great" (p. 10). 
 
 3. Radiation pyrometer (Rosetti, Langley's bolometer, Boys, 
 Callendar disk radio-balance, Joly's meldometer, Crooke's 
 radiometer, Pouillet's pyrheliometer, Fery's pyrometer, mirror 
 telescope, and spiral pyrometer, Thwing, Brown, thermo-electric 
 telescope, Violle's actinometer, Gasparin's pyrometer, Foster) : 
 "Utilizes the total heat radiated by warm bodies. Its indica- 
 tions are influenced by the variable emissive power of the differ- 
 ent substances. It is convenient for the evaluation of very high 
 temperatures which no thermometric substance can withstand 
 (electric arc, sun, very hot furnaces) or when it is not convenient 
 to approach the body whose temperature is wanted. It can be 
 made self-registering" (p. 10). Stefan's law (Stefan-Boltz- 
 mann's law) is that the total energy radiated by a black body is 
 proportional to the fourth power of its absolute temperature. 
 The conception of a black body or absolutely black body is due 
 to Kirchhoff which he defined as one which would absorb all radia- 
 tions falling on it, and would neither reflect nor transmit any; 
 a black body is also called an integral radiator or full radiator. 
 Unless substances are in the condition of a black body their 
 emissive power (for light) will not necessarily be the same for the 
 same temperature. A black body temperature or black tem- 
 perature is understood to mean that shown by a radiation pyro- 
 meter calibrated against a black body. Gray body is the name 
 which has been applied to a body not black but whose properties 
 of radiation have a direct and constant proportion to that of a 
 black body. Radiation pyrometers may also be based on the 
 electric current set up in a circuit of two dissimilar metals when 
 their junction is heated; this is called a thermopile, which has 
 been employed by Nobili and Melloni. . 
 
 4. Optical pyrometer (Becquerel, Le Chatelier, Wanner, 
 Holborn-Kurlbaum, Morse thermogage, Fery absorption pyro- 
 
208 HEAT 
 
 meter and spectral pyrometer, Henning's spectral pyrometer, 
 Shore pyroscope, Mesure and Noiiel pyroscope, Crova, stellar 
 pyrometer, modifications of a photometer, flicker photometer, 
 Nordman's heterochrome photometer, pyrophotometer) : " Util- 
 izes either the photometric measurement of radiation of a given 
 wave length of a definite portion of the visible spectrum, or the 
 disappearance of a bright filament against an incandescent back- 
 ground. Its indications, as in the preceding case but to a much 
 less degree, are influenced by variations in emissive power. 
 The intervention of the eye aids greatly the observations, but 
 diminishes notably their precision. This method is mainly em- 
 ployed in industrial works for the determination of the tempera- 
 tures of bodies difficult of access. For example, of bodies in 
 movement (the casting of a metal, the hot metal passing to the 
 rolling mill). It can be used to establish the highest tempera- 
 tures, and is the best method for use above 1700 C. (3090 F.) 
 in the laboratory and the works" (p. 10). Draper's law is that 
 all bodies acquire incipient luminosity at the same temperature. 
 Selenium has been employed to measure the temperatures of 
 incandescent bodies due to the fact that its electrical resistance 
 is affected by light. 
 
 5. Electrical Resistance pyrometer (Siemens, Callendar and 
 Griffith, Waidner and Burgess) : " Utilizes the variations of the 
 electrical resistance of metals (platinum) with the temperature. 
 This method permits of very precise measurement to 1000 C. 
 (1830 F.), but requires the employment of fragile apparatus. 
 It merits the preference for very precise investigations in labora- 
 tories. As a secondary instrument for the reproduction of a 
 uniform temperature scale throughout the range in which the 
 platinum resistance pyrometer can be used, to 1000 C. except in 
 very heavy wire, it is unsurpassed in precision and sensibility. 
 It is also now constructed in convenient form for industrial use" 
 (pp. 10-11). A logometer is an instrument designed for the 
 measurement of the ratio of two electric currents (Burgess, 221); 
 Northrup's ratiometer is somewhat similar. Holborn and Wien 
 used palladium instead of platinum. 
 
 6. Thermo-electric pyrometer (Becquerel, Barus, Le Chate- 
 lier) : "Utilizes the measurement of electromotive forces devel- 
 oped by the difference in temperature of two similar electromo- 
 tive junctions opposed to one another. In employing for this 
 instrument a Deprez-d' Arson val galvanometer (galvanometric 
 method) with movable coil, one has an apparatus easy to handle 
 and of a precision amply sufficient for industrial and many 
 scientific uses. With a potentiometer (potentiometer method), 
 an instrument is obtained of the most considerable precision, 
 available for use to 1600 C. (2910 F.), or even to 1750 C. (3180 
 F.) with proper precautions. This pyrometer was used for a 
 good many years in scientific laboratories, before it spread into 
 general use, where it also renders most valuable service" (p. u). 
 The two dissimilar elements are termed a couple, thermo-couple, 
 thermo-element, or thermoelectric pair. For high temperatures 
 and special work they commonly consist of combinations of 
 
HEAT 209 
 
 platinum and platinum with about 10% of rhodium (Le Chate- 
 lier's couple), platinum-palladium, etc. (Becquerel), etc.; these 
 are termed noble or rare metal couples owing to their compara- 
 tive freedom from oxidation. Base metal couples are those 
 which, for the sake of cheapness, are made of combinations of the 
 more ordinary metals or alloys, such as copper, nickel, iron, etc.; 
 these are usually restricted to the lower temperatures, say not 
 over about 900 or 1000 C. (1650 or 1830 F.) on account of their 
 greater fusibility or oxidizability. Two special alloys for this 
 purpose are constantan (konstantan, advance alloy) with copper 
 50 and nickel 50, or copper 60 and nickel 40; and manganin 
 with approximately copper 84, nickel 4, and manganese 12. 
 Compound couples are those which either consist of two or more 
 couples in series, to give greater sensibility, or where (to save ex- 
 pense) cheaper substances are used for the portion not subjected to 
 the maximum temperature. The couple is formed by joining the 
 two wires at one end by twisting or preferably welding together, 
 called the hot junction (H. J.). At their other ends they are con- 
 nected to copper wires or suitable lead wires which are connected 
 with the galvanometer or other measuring device; these other 
 ends, or cold junction (C. J.) , of the couple are properly maintained 
 at a constant temperature usually by inserting in melting ice or 
 other substance whose temperature is known as the determina- 
 tion indicates the difference in temperature between the two 
 junctions. Complete expression, however, from the total e.m.f. 
 developed in the thermoelectric circuit requires account to be 
 taken of (i) the Thomson effect : the electromotive forces gener- 
 ated due to differences in temperature along a homogeneous wire; 
 (2) the Peltier effect: due to the heating of the junction of two 
 dissimilar metals anywhere in the circuit; (3) the Becquerel 
 effect : the electromotive forces developed by physical or chem- 
 ical inhomogeneity in'a single wire (Burgess) . The electromotive 
 force generated is ascertained either by the opposition (potenti- 
 ometer) method or by the galvanometric method, the former 
 being the more accurate. 
 
 7. Contraction pyrometer (Wedgewood's contraction pyro- 
 scope) : " Utilizes the permanent contraction that clayey mate- 
 rials take up even when submitted to temperatures more or less 
 high. It is employed today only in a few pottery works" 
 (p. n). 
 
 8. Fusible cones (Seger, Orton): "Utilizes the unequal fusi- 
 bility of earthenware blocks of varied composition. They give 
 only discontinuous indications. Such blocks studied by Seger 
 are spaced so as to have fusing points distant about 20 C. 
 They are in general use in pottery works and in some similar 
 industries (p. n). This method may be classed'as fusing point 
 or melting point pyrometry. In addition to the earthenware 
 cones, similar forms may be made of a series of salts (Grenet), 
 or of metals and alloys (Prinsep) ; these are sometimes referred 
 to as sentinels or sentinel pyrometers. 
 
 9. Pyrometers based on flow or on pressure of air or vapor 
 (Hobson, Uhling-Steinbart, Job, Fournier). 
 
 U 
 
2IO 
 
 HEAT HEAT OF COMBUSTION 
 
 10. Recording pyrometers: (Roberts-Austin, Callendar, Le 
 Chatelier, Siemens and Halske). Those which are provided for 
 plotting, either continuously or at intervals, a chart showing 
 times with corresponding temperatures (p. 12). 
 
 11. Temperature colors are those shown to the eye by incan- 
 descent bodies at different temperatures. The color identities 
 for different temperatures have been investigated by Pouillet and 
 are shown below in what is known as Pouillet's color scale : 
 
 Color names 
 
 Degrees C. 
 
 Degrees F. 
 
 Visible color, first visible red, black red. . . 
 Dull red, low red 
 
 525 
 700 
 
 970 
 1290 
 
 Red, incipient cherry, blood red 
 Cherry, cherry red, bright red 
 Bright cherry . 
 
 800 
 900 
 
 IOOO 
 
 1470 
 1650 
 1830 
 
 Dull orange 
 Bright orange 
 White 
 
 IIOO 
 1200 
 I30O 
 
 2010 
 2190 
 2370 
 
 Bright white 
 Dazzling white 
 
 1400 
 I5OO 
 
 2550 
 2730 
 
 Black heat is any temperature below visible color. 
 12. Miscellaneous Methods: Carnelly and Burton's dilution 
 pyrometer is based on the increase in the temperature of a constant 
 stream of water led through a furnace or other heated chamber. 
 An air dilution pyrometer is usually arranged so an amount of 
 cold air at known temperature is mixed with a known volume of 
 heated blast, etc., and the temperature of the latter determined 
 from the temperature of the mixture. Uhling and Steinbart's 
 transpiration pyrometer or hot blast pyrometer is based on the 
 varying rate at which a gas will flow through a small orifice when 
 heated to different temperatures. Threw's pyrometer is some- 
 what similar in principle. Schaffer and Budenberg's thalpotassi- 
 meter or vapor pressure pyrometer employs the pressure of the 
 saturated vapor of certain liquids (i.e., when both liquid and 
 vapor are present together). Wiborgh's thermophone is a 
 contrivance consisting of a small quantity of an explosive 
 enclosed in a refractory material which is thrown into a furnace, 
 the temperature being calculated from the length of time before 
 the explosion occurs. An acoustic signal is an arrangement 
 consisting of a wire connected with an electric clock; when the 
 wire is melted an alarm is given. A spike indicator, used to 
 determine the temperature of a fused salt bath, is an iron rod 
 which is dipped in the bath, and the temperature calculated 
 from the amount congealed and the corresponding time required 
 to dissolve it off, conditions being maintained uniform (Brearly). 
 Sauveur and Whiting's thermomagnetic selector was a device 
 to determine those rails (or similar objects which were finished 
 at a temperature below the critical, so that their magnetic 
 properties were restored; it was arranged to stamp such rails. 
 
 Heat Balance. Of a blast furnace: see page 36. 
 
 Heat of Combustion. See pages 201 and 203. 
 
HEAT CRACK HEAT TREATMENT 2 1 1 
 
 Heat Crack. See Crack. 
 
 Heat of Disgregation. See page 202. 
 
 Heat Energy. See page 199. 
 
 Heat of Expansion. See page 202. 
 
 Heat of Formation. See page 200. 
 
 Heat of Fusion. See page2oi. 
 
 Heat Interception, Zone of. In a blast furnace: see page 36. 
 
 Heat of lonization. See page 201. 
 
 Heat Measurement. See page 201. 
 
 Heat of Neutralization. See page 201. 
 
 Heat Refining. See page 213. 
 
 Heat Relief .See page 288. 
 
 Heat of Solution. See page 201. 
 
 Heat, Spontaneous Evolution of. See page 199. 
 
 Heat Sums. Law of: see page 201. 
 
 Heat Test. A test, either chemical or physical, representing a heat 
 or melt of steel. This term was formerly applied to a tensile 
 test made op a round (about %" in diameter) forged down from 
 a ladle test ingot or rolled from a billet; same as billet test. 
 
 Heat Tinting. See page 288. 
 
 Heat Treatment (Thermal Treatment). Heat treatment in its 
 most general sense may be taken to mean the application of heat 
 either to make the metal easier to work by rendering it softer or 
 more ductile, or to secure certain desired (and beneficial) changes 
 in its constitution and physical properties without mechanical 
 work . By common usage, however, the term has become restricted 
 to the latter application, for which the writer has suggested the 
 following definition: 
 
 Heat treatment is the change, or the series of changes, in tempera- 
 ture, and also the rate of change from one temperature to another, 
 brought about to secure certain desired conditions or properties in a 
 metal or alloy. 
 
 The term "heat treatment" is frequently but incorrectly used 
 in the restricted sense of quenching followed by reheating, as 
 applied to axles, etc.; when so used it is not considered to apply 
 to annealing or any other treatment properly covered by this 
 term. 
 
 In connection with what follows the article on Metallography 
 should be consulted for explanations of certain special terms 
 necessarily used. For processes or terms employed chiefly for 
 one class of product reference should be made to special articles, 
 such as Malleable Castings, Sheets and Tin Plate, Special Steels, 
 and Wire. 
 
 Heat treatment, like a good rule, will work both ways, and 
 consequently if it is not employed intelligently, or if its presence 
 and effect are overlooked, when material is heated simply for the 
 purpose of working, the results may be disappointing or even 
 disastrous. It should be appreciated that heat treatment acts 
 as an intensifier in the development of the properties of the steel, 
 much as in the treatment of the photographic plate: if the initial 
 quality is good it will be greatly improved, but if bad the final 
 state of that steel is likely to be worse than the first, although 
 
212 HEAT TREATMENT 
 
 in some cases, if this is known, special corrective steps can be 
 taken which may effect a partial but rarely a complete cure. 
 Whether it will prove beneficial or harmful will also depend upon 
 the degree, the rate, and above all the uniformity of heating and 
 cooling. Too much emphasis cannot be laid upon this question 
 of uniformity; it means the same kind of material treated in the 
 same way to get the same results; these three cardinal points may 
 be tabulated as follows: 
 
 1. Uniformity of material: 
 
 (a) The same grade composition within prescribed limits. 
 
 (&) Homogeneity of material freedom from chemical 
 defects represented by harmful segregation, inclusion of 
 foreign substances, etc., freedom from physical defects, 
 such as piping, cavities, injurious and severe strains 
 which, as an extreme case, have actually developed cracks. 
 
 2. Uniformity of treatment: 
 
 (a) Suitable equipment, including furnaces, quenching 
 baths, and pyrometers; the capacity should be ample so it 
 will not be overtaxed in handling a given output. 
 (6) The heating and cooling must be adjusted so that each 
 piece from end to end throughout the section from outside to 
 center, as well as all the pieces in a lot treated together shall, as 
 nearly as possible be at the same temperature at all times. 
 
 3. Uniformity of results : If the other two conditions have been 
 met this one is found to follow. Means should, however, be 
 provided for constantly checking results in order that any errors 
 or carelessness will be promptly discovered and corrected. A 
 further discussion of these conditions will be found in connection 
 with the effect of mass. 
 
 Heat treatment affects the physical or mechanical properties in 
 two ways, by regulating (a) the constituents, and'(6) the grain 
 size. The effect which a given heat treatment will produce varies 
 considerably with the chemical composition; carbon is the prin- 
 cipal or dominant element, and certain other elements, such as 
 manganese, chrome, tungsten, etc., are also very noticeable in this 
 respect. The effect of the special elements is considered more 
 particularly under Special Steel. 
 
 Special heat treatment may be classified under the four heads; 
 (i) hardening, (2) tempering, (3) annealing, and (4) grain refin- 
 ing. Before discussing in detail the first three of these operations, 
 the effect of carbon and grain refining will be considered. 
 
 Effect of Carbon. It has already been stated that carbon is the 
 'element which, more than any other constituent of steel, governs 
 or controls its properties. This effect is due to: 
 
 1. The condition of the carbon. 
 
 2. The distribution of the carbon. 
 
 As regards its condition, the carbon may exist (a) in the free 
 state, as graphite, which in steels is of interest only as a possible 
 impurity; (6) in chemical combination with iron, Fe 3 C or 
 cementite; and (c) in solid solution in gamma (or beta) iron in 
 which it is dissolved (absorbed) either in its elemental form or 
 more probably as the carbide. 
 
HEAT TREATMENT 2 1 3 
 
 The distribution of carbon may be either homogeneous or 
 heterogeneous. It is homogeneous only when the carbon is in 
 perfect solid solution as in such case it must be completely 
 diffused (rarely, equalized or absorbed) throughout the if on in the 
 same way that salt is diffused when dissolved in water, so that 
 individual particles of it cannot be detected even by the aid of 
 the most powerful microscope; unfortunately, however, a 
 solution, particularly a solid solution, may be more highly 
 concentrated in one portion than in another, due to incomplete 
 diffusion or imperfect mixing, and hence is to this extent hetero- 
 geneous. This solid solution is ordinarily normal at high temper- 
 atures above the upper critical point AS (see Metallography), 
 and if it can be preserved when cold by sufficiently rapid cool- 
 ing, its homogeneity must also be preserved. 
 
 The chief (and unavoidable) cause for heterogeneity is the 
 form known as cementite, either free or as the eutectoid mixture 
 with pure iron or ferrite known as pearlite; it may also be 
 present with other constituents. This condition is reached 
 either by slow cooling from above the upper critical point or by 
 reheating to temperatures inferior to A.CI; the restraint of the 
 atoms is sufficiently removed to permit the transformation of 
 some or all of the iron into the alpha variety. The carbon 
 originally in solution in this portion is thereby automatically 
 expelled or precipitated as cementite. There will therefore 
 result a mixture of cementite and ferrite resembling pearlite 
 with an excess of one of these substances unless of eutectoid 
 composition (about 0.85 % carbon) ; as it has been claimed that 
 true pearlite is only produced by slow cooling, it is suggested that 
 the mixture resulting from reheating be termed pearlpid (of the 
 nature of pearlite), and in this discussion the distinction will be 
 observed. Unless the temperature is close to A c\ there is still too 
 much viscosity to permit the molecules sufficient freedom of 
 movement to cause any marked segregation of the ferrite and 
 cementite, so the pearloid has an extremely fine structure. 
 Where the temperature and time of cooling are sufficient, the 
 formation of relatively coarse pearloid will occur. The segrega- 
 tion just referred to is intended in a microscopical sense, and is not, 
 as commonly understood by the term, what is detected by ordi- 
 nary methods of chemical analysis. In actual practice it is well 
 known that of two pieces of the same steel, one merely annealed 
 while the other is quenched and then reheated to Aci, the latter 
 will possess much better physical properties, not only in regard 
 to strength, but to ductility as well. The cause for this is princi- 
 pally found in the distribution of the carbon, as the material is 
 microscopically more homogeneous, although other factors, such 
 as the effect of grain size, etc., may contribute. 
 
 Grain size and growth is affected by heating and by thermal 
 or heat refining ; grain growth is also referred to as crystal- 
 line growth, growth of crystals or crystallization by annealing. 
 Metals and alloys are composed of a number of crystals or 
 
214 
 
 HEAT TREATMENT 
 
 1400 
 
 E 
 
 N 
 
 M 
 
 grains. The irregularity of their form is due to the fact that the 
 growth of each is interfered with by that of the others surrounding 
 it. Therefore, it is only under special conditions that perfect crys- 
 tals are attained. The size of these grains depends upon the 
 maximum temperature above Ac\ at which they have been free 
 to develop, subject to the following conditions: 
 
 If a piece of steel is heated to a temperature corresponding 
 to the point G in Fig. 25 (due to Howe), and is then cooled, it will 
 be found to have a grain size L proportional to this temperature. 
 If it is then reheated the grain size will remain the same until 
 Ac\ has been reached. Immediately on passing this (as at N), 
 the grain is refined to the minimum, that is, from ^V to /, produc- 
 ing a refined structure. This is known 
 as the refining temperature or refining 
 heat. If the temperature is still further 
 raised the grain size increases progres- 
 sively as shown by the curve J D G, 
 and this cycle of changes can be re- 
 peated indefinitely, provided the steel is 
 allowed to cool uninterruptedly from the 
 maximum temperature above Ac\. Ex- 
 cept with eutectoid steel which has a 
 single critical point, when the cooling 
 reaches the upper critical point a sepa- 
 ration of the excess constituent com- 
 mences, and continues until the lower 
 critical point is reached, to form an 
 envelope or skeleton structure about 
 what then becomes the eutectoid. On 
 reheating, this excess substance com- 
 mences to be reabsorbed or dissolved 
 when the lower critical point is passed, 
 but the action is not complete4 until the 
 upper critical point has been reached. Consequently unless this 
 latter temperature is exceeded, portions of the skeleton will remain 
 and prevent a real grain refinement. As a matter of fact hyper- 
 eutectoid steels (with carbon over 0.85%) do not possess this 
 difficulty as apparently the excess cementite crumbles or is 
 broken up after passing the lower critical point, so they can be 
 treated the same as a eutectoid steel. It must be clearly under- 
 stood that the influence of time on grain size is important. 
 Unless ample time is given at the maximum temperature, a 
 given grain may have the same or even a smaller size than another 
 held longer at a lower temperature. 
 
 MetcalP s Experiment. An experiment to show the effect of 
 temperature on the grain size, known as "Metcalf's Experiment," 
 illustrates this very clearly. A description of this experiment 
 was published by William Metcalf in the Metallurgical Review 
 (Vol. I, No. 3, November, 1877), and because of its value as well 
 as the historical interest attaching to it, the following extensive 
 extract is given: 
 
 To show this effect we take a bar of steel of ordinary size, say 
 
 O P L 
 
 Grain- Size 
 
 FIG. 25. Heat refin- 
 ing. (Howe, "Iron, Steel 
 and Other Alloys.") 
 
HEAT TREATMENT 2 1 5 
 
 about inch by half, heat 6 or 8" of one end to a low 
 red heat, and nick the heated part all around the bar at intervals 
 of half to three-quarters of an inch, until eight or nine notches are 
 cut. This nicking is done at a red heat to determine the fracture 
 at the nicks. Then place the end of the bar in a very hot fire, 
 leaving the balance of the bar so much out of the fire as to heat 
 it chiefly by conduction. Heat the end of the bar in the fire to 
 white heat, or until it scintillates, and allow it to remain until 
 the nick furthest from the end in the fire is not quite red, and the 
 next barely red. Now, if the pieces be numbered from one to 
 eight, beginning at the outer end: 
 
 No. i will be white or scintillating; 
 
 No. 2 will be white; 
 
 No. 3 will be high yellow; 
 
 No. 4 will be yellow or orange; 
 
 No. 5 will be high red; 
 
 No. 6 will be red; 
 
 No. 7 will be low red; 
 
 No. 8 will be black. 
 
 As soon as heated as above described, let the bar be quenched 
 in cold water, and kept in the water until quite cold. After 
 cooling, the bar should be carefully wiped dry, especially in the 
 notches. An examination of the different parts by the file will 
 show the following, if high (carbon) steel has been used: 
 
 No. i will scratch glass; 
 
 Nos. 2, 3, 4 will be excessively hard; 
 
 Nos. 5, 6, will be well hardened; 
 
 No. 7 about hard enough for tap teeth; 
 
 No. 8 not hardened. 
 
 In breaking off the pieces, which should be done over the 
 corner of an anvil and the pieces caught in a clean keg or box to 
 keep the fractures clean and bright, it will be found that: 
 
 No. i will be as brittle as glass; 
 
 No. 2 will be nearly as brittle; 
 
 Nos. 3, 4, 5 will break off easily, each a little stronger than' the 
 other; 
 
 Nos. 6, 7 will be very strong, and much stronger than No. 8, 
 or the bar unhardened. 
 
 Place the pieces in the order of their numbers, fitting the 
 fractures, then "up-end" each, beginning with No. i and follow- 
 ing the order in which they lie, and the result will be the series of 
 fractures, each differeing from the other. 
 
 No. i will be coarse, with a yellowish cast, and very lustrous; 
 
 No. 2 will be coarse and not quite as yellow as No. i ; 
 
 No. 3 will be finer than Nos. i or 2, and coarser than No. 8, and 
 will have a fiery luster; 
 
 No. 4 will resemble No. 3 in color and luster, with somewhat 
 finer grain, and will be coarser than No. 8; 
 
 No. 5 will be about the same size as No. 8, but will have fiery 
 luster; 
 
2 1 6 HEAT TREATMENT 
 
 No. 6 will be much finer than No. 8, will have no fiery luster, will 
 be hard through and very strong. This is what is called refined 
 by hardening. 
 
 No. 7 will be refined and hard on the corners and edges, and 
 rather coarser and not quite so hard in the middle. This is 
 about the right heat for hardening taps, milling tools, etc., the 
 teeth of which will be amply hard while there will be no danger of 
 cracking the tool. 
 
 No. 8 illustrates the original grain of the bar. 
 
 What is known as AUing's test is very similar to Metcalf's 
 experiment: A bar, with a longitudinal slot cut on each side, 
 is heated in much the same way, and after quenching is broken 
 along the slot exposing a continuous fracture showing the effect 
 of the varying temperature. 
 
 Grain Growth as Affected by Strain. It was found by Stead 
 in 1898 that iron or very low carbon steel with less than about 
 0.15 % carbon, when heated for a very long time (hours or days) 
 to between 500 and 750 C. (930 and 1380 F.), the grains greatly 
 increased in size and the metal became brittle (hence called 
 Stead's brittleness) . In 1912 Sauveur experimented with some 
 0.05% carbon steel which he heated or "annealed" at 650 C. 
 (1200 F.) for 7 hours, after making an impression with a 
 Brinell machine. In regard to his conclusions he states (Metallog. , 
 266): "These observations point to the conclusion that ferrite 
 grains will not grow on annealing below the critical range unless 
 they have been subjected to a certain stress creating a certain 
 strain, and that they will not grow if that stress, and therefore 
 the resulting strain, has been exceeded. In other words, they 
 point to the existence of a critical strain producing growth, 
 strains of greater .or less magnitude being ineffective. The 
 narrow region occupied by the critically strained metal should 
 also be noted as well as the very sharp line of demarcation be- 
 tween the critically strained and the understrained metal. 
 The separation of the critically strained from the overstrained is 
 not so sharp." The critical strain is also referred to as critical 
 deformation, Sauveur's critical strain, and Howe refers to 
 "Sauveur's process of coarsening ferrite by heating it to below 
 AZ after a critical degree of plastic deformation." 
 
 As a result of his investigations on this subject, Chappell 
 (/. /, 6* S. /., 1914, 465) draws the conclusions as to the changes 
 involved in the recrystallization of severely worked ferrite: 
 
 (a) Up to 350 C. no visible reorganization takes place. 
 
 (b) From 350 to 500 C. potential recrystallization takes place 
 in the shape of disintegration of the deformed crystals into what 
 has been termed crystal debris. This is stage I. 
 
 (c) Below 500 to 570 C. new crystals are formed among this 
 Crystal debris, which new crystals grow rapidly from almost 
 ultramicroscopic dimensions into normally shaped allotrimorphic 
 crystals easily visible at high magnifications. This is stage II. 
 
 Grain Size and Mechanical Refining. For the economical 
 production of various shapes and sections by rolling or forging, 
 it is essential to heat the metal to a relatively high temperature 
 
HEAT TREATMENT 
 
 217 
 
 1400 
 
 so it may be as soft and ductile as possible. If the metal were 
 simply cooled from such a temperature it would be coarse- 
 grained, and the cohesion between the grains would be weakened. 
 This would mean increased brittleness and decreased resistance 
 to shock, which would render the material unsuitable for many 
 purposes. 
 
 However, when mechanical working occurs, the grains are 
 reduced to a size dependent chiefly upon the temperature at 
 which this work ceases and, in a somewhat less degree, upon the 
 size or mass of the piece, it being of 
 course supposed that the work affected 
 the entire section. The explanation for 
 this is readily appreciated by referring to 
 Fig. 26 (also due to Howe). The grains 
 or crystals of iron in their normal condi- 
 tion are equiaxed and belong crystallo- 
 graphically to the isometric or cubic 
 system, that is, their three axes are at 
 right angles to each other and of equal 
 length. When the length of a piece is 
 increased by rolling or forging, there 
 must be a proportional decrease in the 
 cross-sectional area. The small grains or 
 crystals which make up the structure 
 must be deformed to at least the same 
 degree. This produces a condition of 
 unstable crystallographic equilibrium, 
 since the axes are of unequal length 
 (inequiaxed). To regain the normal state 
 each grain tends to split up into several 
 grains of smaller size, depending upon 
 the shortest axis which limits that of the other two. At the 
 relatively high temperatures ordinarily employed for mechanical 
 working, the molecules have sufficient freedom of movement to 
 bring this about. 
 
 The curve Ac\A is the grain-size curve of Fig. 25 just discussed. 
 If a piece of steel at a temperature, and with corresponding 
 normal grain size, as at A, is sufficiently deformed by a single 
 operation of mechanical working, the grain size will be reduced 
 from A to B, equal to OH. If the piece could then be cooled 
 instantaneously, this size should be preserved. Under ordinary 
 circumstances, however, the cooling requires some time. In this 
 case the grain size, being below the normal for the existing 
 temperature, increases progressively toward that normal size. 
 Unless interrupted, the cooling of the piece and the increase in 
 grain size from B is along the curve BCE. After crossing the 
 curve Ac\A no change in the grain size takes place, as already 
 explained in connection with Fig. 25. The final size is conse- 
 quently OE. 
 
 If, however, when C is reached, mechanical working is again 
 applied, the grain is reduced to D. By further repetitions of 
 cooling and working the zig-zag curve ABCDG is followed 
 
 OHP O 
 
 Grain - Size 
 
 FIG. 26. Mechani- 
 cal refining. (Howe, 
 "Iron, Steel and Other 
 Alloys.") 
 
2 1 8 HEAT TREATMENT 
 
 until G is reached. If this is the finishing temperature, the 
 growth of the grain proceeds until, with the temperature steadily 
 falling, the curve Ac\A is crossed, but this time at a much lower 
 point than before, the final grain size being OP. 
 
 It will thus be seen that for pieces of the same size, that is, 
 with the same rate of cooling, the grain size will depend upon the 
 finishing temperature. 
 
 Theoretically, it would be desirable to finish just above Ac\. 
 but, owing to the rapidly diminishing ductility, this is usually 
 not practicable because of the danger of breaking or overtaxing 
 the rolls or hammer, or of producing excessive strains in the 
 material itself. This last is especially true if the piece is of 
 very irregular section, since the molecules have lost much of 
 their freedom of movement. 
 
 As a general proposition, the finest grain must be secured by 
 reheating, because the piece can then be held a sufficient length 
 of tihie at the proper temperature to enable the necessary re- 
 arrangement of the molecules to occur, which is not possible with 
 mechanical working because the temperature is constantly 
 falling. 
 
 If the grain size of two pieces of steel of the same size are 
 compared, one of which was worked from a higher temperature 
 and allowed to cool, and the other reheated to the same tempera- 
 ture and similarly cooled, the grain size of the first piece is the 
 smaller unless the cooling is extremely slow; and the faster the 
 cooling the greater the difference. The explanation for this is 
 because the final working reduced the size to below what was 
 normal at that temperature and the temperature had fallen con- 
 siderably before the grain was of correspondingly normal size; 
 with the second piece the heating was slow enough to permit of 
 a much nearer approach to the normal correspondence between 
 grain size and temperature. 
 
 Combined Treatment for Grain Size and Carbon. From the 
 preceding it will be seen that there can be secured by suitable 
 heat treatment any one of the following possible combinations : 
 
 1. Grain size either (a) fine or (6) coarse, with 
 
 2. Carbon either (c) in solution (homogeneous) or (d) precipi- 
 tated (heterogeneous) ; and for 2 ( d} only, with 
 
 3. Microscopic segregation either (e) fine or (0 coarse. 
 Having taken up separately the various conditions which are 
 
 met, we can now consider how heat treatment can be employed 
 to obtain the best results. To this end we secure as far as possible : 
 
 1. A fine grain size. 
 
 2. Fine and uniform" distribution of the carbon and allied 
 constituents. 
 
 Only in the case of a eutectoid steel can this combination be met 
 by simple treatment. Assume the complicated case of, say, a 
 '5o% carbon steel in an ordinary condition which is to be made 
 as soft as possible, and with the carbon in a fine state and uniformly 
 distributed; after this the simpler cases can be readily determined. 
 Such a steel as received will have been slowly cooled after rolling 
 or forging. Its structure consequently will be composed of 
 
HEAT TREATMENT 2 1 9 
 
 relatively coarse grains of pearlite surrounded by, or interspersed 
 in envelopes or bands of excess ferrite, the latter being expelled in 
 cooling through the critical range between -4r 3 -2, and Ar\ (OS 
 and PS in Fig. 38, page 271). The following procedure is then 
 followed which, except for complications frequently encountered 
 which must be specially handled, will approximate the desired 
 results: 
 
 1. Heat (at any rate of speed consistent with uniform 
 heating) somewhere above Ac 3 , and cool rapidly. Heating to 
 above Aci would be sufficient to convert the eutectoid portion 
 into a solid solution, but the higher temperature is necessary 
 to effect solution of the excess ferrite; rapid cooling preserves 
 the homogeneous condition. The metal is then homogeneous in 
 composition but is hard and coarse grained. 
 
 2. Heat rapidly just above Ac\ and cool rapidly. The heat- 
 ing below Aci causes precipitation of carbide, and by passing 
 above this point the cementite and ferrite in eutectoid proportions 
 are converted into a solid solution; the excess ferrite is not (or only 
 very slightly) affected, but it is scattered throughout the mass in 
 minute fragments, and not as continuous bands, hence is in the 
 least injurious condition; the rapid heating and cooling tend to 
 prevent microscopic segregation. The metal is partly homoge- 
 neous and partly heterogeneous, still relatively hard, but with a 
 fine grain. 
 
 3. Reheat rapidly to slightly below A Ci and cool rapidly. The 
 solid solution of eutectoid is converted into pearloid and the 
 rapid heating and cooling (as before) tend to discourage segrega- 
 tion; the rapid cooling from below Ac\ does not cause hardening. 
 The metal is now soft, necessarily heterogeneous but the cemen- 
 tite and ferrite are as uniformly and finely distributed as possi- 
 ble. Q.E.F. 
 
 Effect of Mass on Physical Condition and Properties. In 
 what has gone before it has been assumed that the piece has been 
 small, that is, without appreciable mass, and in most discussions 
 this question is ignored. 
 
 FIG. 27. Manner of transmission of heat. (Tiemann.) 
 
 In practically all experiments which have furnished the infor- 
 mation we at present possess, relatively very small pieces were 
 employed. It is possible to heat or cool such pieces nearly 
 uniformly throughout, about as rapidly as desired. When, 
 however, the attempt is made to put into practice the principles 
 so obtained, it is found that a new factor enters largely into the 
 problem, namely, the mass of the object treated. For example, 
 if a piece of fine wire is heated and then exposed to air at the 
 
220 HEAT TREATMENT 
 
 ordinary temperature, it will be cooled almost instantaneously, 
 while the time required in the case of a large shaft, even when 
 plunged into cold water, will be many minutes. 
 
 Under similar conditions the rate of heating and cooling is 
 much less for a large than for a small section, for two reasons: 
 
 i. Because the distance to be traversed between the surface 
 and the center, in the absorption or dissipation of heat, is 
 greater. This rate progressively decreases as the temperature 
 of the body, or of one portion of the body in relation to another 
 portion, approaches that of the source of heat or refrigeration, in 
 accordance with one of the fundamental laws of thermodynamics. 
 Fig. 27 is intended to illustrate how the transference of heat occurs 
 between different portions of the surface and the interior. AB- 
 CD is a section through an object uniformly heated or cooled 
 
 Rati< 
 
 Diameter Relative Relative Area fr 
 of circle Circum. Areas Circum 
 i i i i 
 
 2242 
 3393 
 
 4 4 16 4 
 
 5 5 25 5 
 
 6 6 36 6 
 
 7 7 49 7 
 
 8 8 64 8 
 
 9 9 8l 9 
 IO * IO 100 10 
 
 FIG. 28 Relative Amounts of Heat Trans 
 mitted per Unit of Area of Surface. 
 (Tiemann.) 
 
 on all sides. The transference of heat to ABFE is through AB; 
 to A ED through A D, etc. The progressive effect is indicated 
 by the dotted lines which are rounded at the corners of the 
 section, because in those regions it is obtained from two 
 sides. 
 
 2. Because the cross-section increases directly as the square 
 of the diameter, while the circumference increases only in simple 
 proportion to the diameter. The same relation also exists 
 between surface and volume (mass), since these are obtained by 
 multiplying the circumference (or perimeter) and the area, 
 respectively, by the same value representing the length. In 
 Fig. 28 is a table of ratios between circumference and area for 
 circles of diameters of i to 10. In the same figure are shown 
 three circles with diameters of i, 2 and 4. The hatched portions 
 show graphically that the same linear distance on the circum- 
 ference of each must serve for the transfer of amounts of heat 
 which are respectively i, 2 and 4; as already explained these 
 ratios are the same if the surfaces and volumes (masses) are 
 substituted. 
 
HEAT TREATMENT 
 
 221 
 
 This may be summarized in the following general law for the 
 transference of heat : 
 
 For bodies of similar section the amount of heat transferred per 
 unit of surface is directly proportional to the ratios of their dia- 
 meters (or similar dimensions of their cross-section). 
 
 The preservation in the cold state of the condition which 
 existed at the temperature to which an object is heated (above 
 the critical point) is dependent upon a certain rate of cooling, 
 irrespective of the size or mass of that object. . With the means 
 at our command it will readily be appreciated that a point is 
 very quickly reached when no method of cooling can compensate 
 for the increase in mass, so that the rate of cooling decreases with 
 corresponding increase in the actual time required. 
 
 Ductility 
 
 FIG. 29. Diagram used for discussing effect of mass. (Tiemann.) 
 
 As a direct result the interior of large masses will be cooled so 
 slowly as to have only the properties of smaller masses cooled in 
 the same time, or, in other words, the effect has been that of 
 annealing rather than of quenching, as these terms are com- 
 monly understood. The exterior portion, although considerably 
 retarded in its cooling by the necessary transfer through it of 
 heat from the interior will be benefited in proportion to the rate 
 at which its temperature was brought below the critical range, 
 the properties of different portions of such a piece being in inverse 
 proportion to the distance from the surface. 
 
 Fig. 29 is intended to show this state of affairs graphically, 
 but without any claim as to its quantitative or even its qualitive 
 accuracy. It is based on the quality formula Q = S X D 
 given on page 341. The curve AB is supposed to represent 
 the maximum theoretical relation between strength and duc- 
 tility for steel of any given composition; steels of other 
 composition would be represented by curves varying pro- 
 gressively from one another. If it be tentatively admitted 
 that this curve is correct, then a piece with the properties corre- 
 sponding to the point A, with relatively high strength and low 
 
222 HEAT TREATMENT 
 
 ductility, would be of equal merit with another piece with 
 properties B, where relatively low strength is combined with high 
 ductility; or with a piece with properties represented by any 
 other point on the curve, since the curve is drawn on the assump- 
 tion of a constant value for the relation between strength and 
 ductility. 
 
 If a piece had only the properties C, the strength, according 
 to our assumption, could be increased to C', the ductility remain- 
 ing the same; or the ductility could be increased to C", the 
 strength remaining the same; or any other maximum relation 
 could be attained, as C'", on the curve A B. 
 
 In actual practice or experiment, however, the factor of mass 
 is bound to enter in, even with the smallest obtainable section, so 
 that this maximum curve can only be approached but never 
 quite reached. With very small pieces the experimental maxi- 
 mum might be as represented by the curve A' B'; other curves 
 A" B", A"' B'", etc., would, in the same manner, represent 
 the possible maxima which could be attained by pieces of in- 
 creasing section. 
 
 If the point C, for example, represents the properties of a 
 large untreated section, these could probably be improved by 
 annealing to some point E, or by quenching and tempering to F 
 or G. With cooling more rapid than usual, as by quenching in 
 iced brine or liquid air, followed by tempering, the point D might 
 be reached. 
 
 The reason for the higher relation of properties in a small 
 section over that in a large section, treated under the same 
 conditions, would appear to be due principally to the condition 
 of the carbon. This is also borne out by the difference in the 
 properties of test specimens cut respectively from near the 
 surface and at the center of large sections, which has resulted in 
 the clause in forging specifications that "the axis of the specimen 
 shall be located at any point one-half the distance from the 
 center to the surface and shall be parallel to the axis of the object 
 tested," with a view to determining the average values. 
 
 Effect of Mass on Strains Produced in Heat Treatment. Un- 
 der suitable conditions of heating it is possible to secure a reason- 
 ably uniform temperature throughout a fairly large section. If 
 the rate of cooling could then be controlled so that a large section 
 could be cooled as rapidly (that is, in the same time) as a A smaller 
 object, the uniformity of the material in the two cases should be 
 the same. As a matter of fact, however, such a state of affairs 
 cannot be attained, as the conduction of heat from the center 
 to the outside of a section of any size is relatively slow for the 
 reasons already given, and cannot be hastened sufficiently by any 
 means at our command. Even if such were not the case, there is 
 another insurmountable obstacle - in the path. This is the 
 possible introduction of excessive strains in large pieces, par- 
 ticularly where there is any irregularity of section. Rupture or 
 incipient cracks resulting from this would not be corrected 
 by any heat treatment alone. Such cracks from irregular 
 contraction due to unequal cooling, are termed treatment cracks, 
 
HEAT TREATMENT 
 
 223 
 
 heat treatment cracks, cold cracks, etc. (see Cracks, p. no); 
 clinking is an English term to describe the sound when material 
 cracks from irregular expansion due to too rapid, i.e., unequal 
 heating. Fig. 30 is intended to illustrate how such cracks or 
 strains can develop when a large object is too rapidly cooled by 
 quenching or otherwise. For simplicity, only linear expansion 
 and contraction at one end are considered. A BCD is the 
 
 Compression^ B g" B ' 
 
 \D 
 
 IF E 
 
 
 Tension ' 
 
 & Compression' 
 
 FIG. 30. Method of development of quenching strains and cracks. 
 (Tiemann.) 
 
 original length when free from all strains. AB'C'D is the 
 length when heated to the quenching temperature. If the 
 cooling is progressively slower from outside to center, and each 
 successive layer is deformed in length by the obstruction to full 
 contraction offered by the interior layers, the appearance of the 
 piece would be as shown by the curve B'EC' ', provided each 
 layer could assume its new length. However, as they are all 
 firmly bound together, the piece will assume the intermediate 
 rectangular section AB"C"D. The strains vary from maxi- 
 
 FIG. 31. Internal quenching crack. (Tiemann.) 
 
 mum compression at the outside to maximum tension at the 
 central axis. If this latter strain exceeds the elastic limit, 
 the central portion must stretch and may go far enough to de- 
 velop a crack, particularly if some flaw already existed, thereby 
 upsetting the equilibrium of forces. The crack will then con- 
 tinue to spread until nearly all the strains have been released. 
 Such an internal quenching crack is shown in Fig. 31 (based on 
 
224 HEAT TREATMENT 
 
 actual cases of service failures). The shaded portion shows the 
 original extent of the crack; the sound (unshaded) portion was 
 insufficient to withstand the shocks and stresses in service. 
 H. Le Chatelier (/. /. & S. I., 1914, 1, 247), in discussing causes of 
 rupture in hardening by quenching, says that while he does not 
 deny the possibility of the two causes from irregular distribution 
 of temperature during quenching, and differences in expansion 
 caused by non-uniform hardening, there is a third cause which is 
 more frequent and more important. "At the moment of the 
 transformation of the austenite into martensite, that is, gamma 
 into alpha iron, in the solid solution, a sudden and considerable 
 increase in volume occurred. That transformation did not take 
 place at every point within the mass at the same moment. At 
 each point at which it occurred, there were developed, momen- 
 tarily, enormous stresses which led to cracking. After cooling 
 they ultimately reached the same state." 
 
 Density as Affected by Heat Treatment "E. H. Schulz has 
 studied the changes of volume and form of steel due to heat 
 treatment, a subject concerning which little exact knowledge 
 exists. The following is a summary of the author's main con- 
 clusions. In annealing, the density of carbon steel decreases as 
 the carbon percentage increases, but the decrease is not regular, 
 and an irregularity occurs with 0.5% of carbon. By 
 quenching, the density is decreased by an amount which is greater 
 as the carbon increases. Below 800 to 900 C. the volume in- 
 creases rapidly as the quenching temperature is raised, but above 
 that range the quenching temperature has little effect on the den- 
 sity. In the case of high-carbon steels, quenching in water always 
 confers greater density than quenching in oil, the difference being 
 most marked in steel containing the eutectbid proportion of car- 
 bon. The original density of the steel is never restored by 
 annealing after quenching, but the difference of density in the two 
 states can be reduced by successive quenching and annealing. 
 Electrolytic copper and electrolytic iron tempered at 150 C. both 
 show a large increase in density, due to irregularities of a purely 
 physical nature, and the density is considerably influenced by the 
 rate of cooling after tempering. The density of quenched steel is 
 increased on tempering by an amount increasing with the carbon. 
 The density -tempering temperature curves are very irregular, but 
 all show a maximum at 430 C. (810 F.). 
 
 "In alloy steels the difference in density as between water- 
 hardened and oil-hardened steels is not so great as in the case of 
 ordinary carbon steels. Quenched alloy steels show no maximum 
 at 430 C., but from that temperature upward the density in- 
 creases continually. Eutectoid steels tend more than others to 
 develop hardening cracks, on account of their greater volume 
 changes during quenching. Bars increase in length according to 
 the carbon content, and the increase is proportional to the length 
 of the bar. 
 
 " When quenched from 960 C. (i 760 F.) in water several of the 
 special steels always gave hardening cracks, so that the specific 
 gravity could not be determined. The nickel and chromium 
 
HEAT TREATMENT 225- 
 
 steels show a smaller increase in volume with quenching than 
 plain steels of the same carbon content 
 
 "This is also true of the manganese steels, although not to so 
 great an extent, while the chromium-nickel steels shows a pro- 
 portionally great change of volume. Although these results 
 do not apply to all special steels, yet it is certain that through 
 suitable special additions the change in volume due to quenching 
 can be greatly reduced. 
 
 "The author considers that the change in volume brought about 
 by quenching steel is only small if the quenching temperature be 
 within a limit close to the critical temperature. Very great 
 changes in volume are brought about if this limit is even slightly 
 exceeded" (Abstr. from Zts. Ver. deuL Ing. in /. /. &" S. /., 
 1915, II, 303-4)-. 
 
 The increase in volume from quenching is due not simply to 
 quenching strains but also to the change in density of steel from 
 one allotropic variety of iron to another. The temperature- 
 density curve shows at first a regular decrease of density on 
 heating, then a sudden reversal through a certain range (corre- 
 sponding closely with the critical), changing back- again to a 
 progressive decrease above this. Based on researches along these 
 lines the Packard Motor Company has devised a process whereby 
 they are able to (a) increase, (b) decrease, or (c) maintain constant 
 the size of an object by selecting the suitable quenching tempera- 
 ture as demonstrated by means of a round plug machined so it 
 will barely pass through a corresponding hole in a plate. 
 
 It should be appreciated that where increase of volume occurs 
 an object tends to assume a spherical form which is known to 
 possess the minimum superficial area for a given volume. As an 
 illustration of this fact, a high-carbon die used in wire drawing, 
 which was originally cylindrical, after say a hundred or more 
 quenchings (for the purpose of restoring the hole), became nearly 
 spherical. This accounts for the slight shortening observed 
 in cylindrical objects, such as shafting, after quenching operations, 
 provided excessive longitudinal strains were not set up sufficient 
 to cause actual rupture, and which were largely removed by sub- 
 sequent reheating. 
 
 We are therefore confronted with the contradictory state of 
 affairs that the larger the section the more vigorous should be the 
 cooling; and the more vigorous the cooling the greater the liability 
 to excessive strains or rupture. While the component particles 
 of the .material may be advantageously affected, the object as a 
 whole suffers. From this it is evident that for any given size 
 or section there is a maximum relation between ductility and 
 strength, which decreases as the dimensions increase; that if 
 the strength is maintained constant the ductility must decrease, 
 and vice versa, as discussed in connection with Fig. 29. 
 
 It must consequently be realized that the possibilities as re- 
 gards the physical properties of large sections are not so great as 
 in the case of small sections, and this must be taken into considera- 
 tion in drawing up physical requirements. For, restating the 
 case briefly, under similar circumstances: 
 15 
 
226 HEAT TREATMENT 
 
 1. The condition of the carbon and the grain size depend upon 
 the temperature and the rate of cooling. 
 
 2. The rate of cooling depends upon the diameter or thickness 
 of a given section, and probably also to a certain extent upon the 
 length, or, in other words, upon the mass. 
 
 3. The rate of cooling through the critical range, and just 
 below the lower critical point, is of much greater importance 
 than during any subsequent tempering (after quenching). 
 
 To determine the uniformity of heating, the temperature musl 
 be of unquestioned accuracy. Further, the rate of heating must be 
 carefully determined by experiment to secure proper penetration 
 It will be seen that the principles involved are comparatively 
 simple. The main difficulty in carrying out the operation' 
 commercially is found in securing the necessary degree of uni 
 formity. It is for this reason that special equipment is so essen- 
 tial. Of equal importance is the proper material, the compositior 
 of which must be definitely known, as variations, particular!) 
 in carbon, will result in different physical properties being securec 
 under the same conditions of treatment. 
 
 Overheating and burning result when steel or iron has beei 
 heated to a very high temperature which is respectively moderatel) 
 close and very close to the melting point. Both these effect: 
 are frequently termed overheating, but this should be avoided 
 The overheating zone and burning zone are the respective range; 
 of temperature where these effects occur. In overheating th( 
 grain is rendered very coarse, and the cohesion between the grain; 
 is lessened so the metal is tender; the normal condition can b< 
 restored by heat refining alone, or better, in combination witl 
 mechanical working. In burning the condition may range fron 
 extreme overheating to where the more fusible constituents mel 
 and run out from between the grains, giving rise to a shower o 
 brilliant sparks. The former condition can probably, at leas 
 partially, be corrected by heat treatment and mechanical work 
 ing, but steel in the latter condition is hopelessly ruined, and i: 
 fit only to be remelted, and is said to be oxygenated. If higl 
 carbon steel is heated for some time, with access of air, to a tern 
 perature not necessarily high enough to cause overheating, some 
 of the carbon becomes oxidized, and the steel is termed roastec 
 or baked. A similar steel, repeatedly heated and hardened 
 in time acquires a brittle exterior, which must be removed t< 
 restore its good qualities, and when in this condition is sometime: 
 said to be dead. To give a piece a short heat mean^ to heat i 
 for a small portion of its length only, as where one end is to b 
 upset or swedged in. After an object, especially of tool steel 
 has been heated, particularly for a long time and at a high tern 
 perature, there is a skin or layer just beneath the scale, which i 
 nearly decarburized, and is called the bark ; this layer is some 
 times as much as an eighth of an inch thick. 
 
 Hardening. This, as commonly understood, consists in impart 
 ing to steel an appreciable or useful hardness for which a suitabb 
 grade, i.e., a composition (principally carbon and certain specia 
 elements) which lends itself to this purpose, is necessary. It ma; 
 
HEAT TREATMENT 227 
 
 include cases where the tensile strength and elastic limit of soft 
 steels are raised, but the line is roughly drawn to include such 
 steels as can be made very resistant to abrasion, indentation and 
 bending, where they are to be fashioned into cutting tools, 
 hammers, drifts, crow bars, bearing parts, agricultural imple- 
 ments, and similar objects. Hardening is sometimes secured by 
 cold working, by which means a temporary cutting edge, for 
 example, may be given to even the softest steel or iron, but is 
 ordinarily accomplished by heat treatment alone. In this latter 
 case, with which we are concerned, the material is heated to 
 above a certain critical temperature followed by rapid cooling. 
 The degree of hardness obtained will, in general, vary directly 
 with (a) the percentage of carbon, (b) the rate of cooling, and 
 (c) the temperature above the critical point from which the 
 cooling takes place. If the object is very small it may be suffi- 
 cient to remove it from the source of heat and expose it to the 
 air or a blast (air cooling, air hardening, and particularly if a 
 blast is used, air quenching), but as a rule this is not sufficiently 
 rapid, and in such cases the article is plunged into some liquid 
 (quenching bath or quenching medium) or sometimes sprayed with 
 it, to remove the heat faster; this operation is known as quenching, 
 quenching hardening, or hardening, qualified properly by the name 
 of the medium employed (unless clear from the context), e.g., 
 water hardening (quenching) ; lead hardening (quenching). The 
 term cooling is also used in the same manner, as water cooling, oil 
 cooling, air cooling, etc. Water quenching is rarely called water 
 dipping. The temperature to which the object is heated for 
 quenching is referred to as the quenching temperature. The 
 term quenching has been and still is commonly understood to con- 
 note the use of water, in the sense of extinguishing, as a fire, or 
 destroying or allaying, as thirst, in both cases as with red hot 
 iron with the idea that this was secured by removing heat. This 
 latter meaning has most strongly persisted in the case of heat 
 treatment, hence the extension of the term to include at first 
 liquid media other than water, and later air, etc. While, as just 
 stated, quenching now properly signifies the rapid extraction 
 of heat, and is therefore commonly used in the same sense as 
 hardening, yet manganese steel or high-nickel steel (both of which 
 are austenitic), for example, plunged into water from a yellow 
 heat, are quenched and toughened, but not hardened; this par- 
 ticular result is termed water tempering or water toughening; in 
 contradistinction the ordinary result of quenching is referred to 
 as quenching hardening. Tempering is sometimes employed (but 
 confusingly) to mean the same as hardening, and in this sense 
 the term temperability has been suggested to indicate the capa- 
 bility of steel of being hardened. 
 
 The temperature and the nature of the liquid determine the 
 rate of cooling, and also the temperature to which the object 
 may be cooled. There is no inherent or peculiar virtue or dif- 
 ference, per se, in any one medium over another, except what 
 relates to the respective ability to extract heat and so affect the 
 rate of cooling; in other words, it is the rate of cooling which is at 
 
228 HEAT TREATMENT 
 
 all times responsible for the results, irrespective of the means 
 employed. Iced brine and cold water are two of the most effective, 
 and oil and molten lead are less active in the order given. Since 
 the effect on the rate of cooling of the two last is not so great, 
 being similar to water hardening followed by tempering, the 
 operations in which they are employed are frequently called 
 oil tempering and lead tempering, but the terms oil hardening 
 and lead hardening are preferable. As a rule, plain carbon steels 
 where actual hardening is desired, contain carbon over 0.60%; 
 where an increase in strength and elasticity is desired, without 
 a material reduction in ductility, for axles, shafts, etc., the carbon 
 is usually between 0.35 and 0.60%. The temperatures recom- 
 mended by the A. S. T. M. for annealing operations are as follows: 
 
 Range of Carbon Range of Annealing Temperature 
 
 Content 
 
 Less than 0.12% 875 to 925 C. (1607-1697 F.) 
 
 o.i 2. to- 0.29% 840 to 870 C. (1544-1598 F.' 
 
 0.30 to 0.49% 815 to 840 C. (1499-1544 F. 
 
 0.50 to i .00% 790 to 815 C. (1454-1499 F. 
 
 Double hardening consists in quenching the article twice, 
 usually in oil or water (see double quenching, page 233). Double 
 quenching is particularly applicable to casehardened objects 
 consisting of a low-carbon core with a high critical point, and a 
 high-carbon case with a much lower critical point : by a prelimi- 
 nary high temperature quenching (regeneration quenching) the 
 core is refined, followed by quenching from a lower temperature 
 suitable for the core (hardening quenching). Broken harden- 
 ing, specially applicable to tools of irregular section, such as mill- 
 ing cutters, consists in quenching in water until the disappearance 
 of color and then transferring to, and completing the cooling in, 
 oil. Differential or decremental hardening (sometimes called 
 differential cooling) is where the entire object is heated to a 
 hardening temperature but only a portion is hardened by quench- 
 ing. For example, a common method of hardening chisels is to 
 (a) heat, (b) plunge the point in water until cold, then (c) rub one 
 side on a brick or piece of emery paper to get a bright surface, (d} 
 allow the heat to diffuse from the still hot portion until the proper 
 temper color (see below) is obtained, after which (e) the whole 
 piece is plunged at intervals in the water to prevent further tem- 
 pering, but so the cooling does not unduly harden the back part 
 which must be relatively soft and tough. About the same result 
 may be reached by differential heating (sometimes called flash 
 heating), whereby only the portion to be hardened reaches a 
 temperature above the critical, when the whole object is plunged 
 in the quenching bath. If the piece is quenched as soon as the 
 temperature passes the critical point, and is still rising, it is called 
 hardening on a rising heat. Since the critical point on cooling 
 is lower than on heating, it is possible, after the temperature has 
 risen above this to hold the piece in air (or otherwise) until the 
 temperature is slightly above the recalescent point and then 
 
HEAT TREATMENT . 229 
 
 quench. Also at a temperature slightly above what is neces- 
 sary for hardening, there will be greater certainty of the trans- 
 formation being complete. The hardening effect will not be so 
 great as in the former case but the lower temperature will have 
 less tendency to set up injurious strains; this is called hardening 
 on a falling heat. Press hardening is employed for thin objects, 
 such as saw blades, and consists in pressing the heated object in dies 
 which serve both to harden and to flatten it. The dies can be so 
 shaped as not to come in contact with parts which are not to be 
 hardened. Crocodile skin is the name given to the appearance 
 resulting from oil or grease on the surface which has not entirely 
 burned off during the heating, or leaves a deposit producing a 
 different coloration. 
 
 Special Methods of Hardening. Caron's method consists in 
 quenching in hot water (hot water hardening), by which, owing 
 to the slower rate of cooling, is secured an effect equivalent to 
 ordinary hardening plus tempering; except with small pieces con- 
 taining high carbon, a negative quenching effect (see below) will 
 result: In James Chesterfield's process coiled strips or tapes are 
 heated in a box, the end projecting through a hole. When hot 
 enough they are pulled out and passed between water-cooled 
 blocks, after which they are tempered by coating with oil which 
 is burned off. In Clemandot's process a bar of steel heated to a 
 bright cherry is subjected to great pressure between the faces of a 
 hydraulic press (or otherwise) . It was claimed that the steel was 
 thereby rendered harder and of a finer grain (refining by harden- 
 ing) than when hardened in the ordinary manner. This is some- 
 times called hardening or tempering by compression or pressure 
 hardening. It closely resembles press hardening mentioned 
 above. By the Jarolimek process the red-hot steel is held in the 
 comparatively dense center of a spray of water until black, and 
 then allowed to cool in the outer less dense portion of the spray at 
 a rate which is claimed to be controllable; or, if the object is of 
 very small size, in the air. Chas. Gill's method of quenching 
 was to use easily fusible alloys, such as lead and tin, lead, or tin 
 and bismuth, which were kept at such a temperature that a sub- 
 sequent tempering operation was unnecessary. Osmond sug- 
 gests molten zinc instead of lead as the former does not give off 
 noxious fumes, is cheaper, and the slightly higher melting point 
 should be more than offset by its possessing three times the 
 specific heat. Ferret's method (later studied by Jarolimek) was 
 to use a blast of air loaded with water vapor. Reaumur's process 
 was to harden the points of tools by sticking them into (and let- 
 ting them melt) solid lumps of tin or lead. He also suggested 
 gold, silver and copper for this purpose. Seguin's process con- 
 sists in quenching steel, heated to a cherry red, in either (a) dilute 
 sulphuric or hydrochloric acid, or (b) in a mixture of turpentine 
 and water. In the Terre-Noire process, projectiles (which were 
 simply cast and bored out) were heated to a red heat, the point 
 only dipped into water until black, and the whole piece then 
 plunged into oil and kept there until cold. This was followed 
 by reheating to a temperature just high enough to remove the 
 
230 HEAT TREATMENT 
 
 adhering oil. G. Theodossief's process consists in quenching in 
 glycerine, either pure or mixed with different proportions of 
 water, and sometimes containing certain salts; the temperature 
 may also be varied depending upon the nature of the steel and 
 upon the results desired. The Tressider process (specially 
 applicable for armor plate) consists in applying the quenching 
 liquid in the form of a spray to one or both sides of the heated 
 piece, as desired. A number of other special processes have been 
 patented and suggested from time to time, for example : the utili- 
 zation of the latent heat of fusion of various mixtures of water or 
 lime with ice, or of ice alone (Schneider et Cie.) ; easily fusible 
 alloys and salts; water covered with a layer of oil. Electric 
 hardening consists in heating the piece by means of its resistance 
 to the passage of an electric current, or by an electric arc, 
 after which it is quenched as usual. Electricity may similarly 
 be employed for heating to a lower temperature for tempering 
 (electric tempering). The Lagrange and Hoho process depends 
 upon the fact that the outer portion of a small piece of steel, 
 forming the negative pole in an electrolytic solution, may be heated 
 to a bright red by the passage of an electric current of fairly 
 high voltage and low amperage, before the interior is sensibly 
 affected; if the current is then interrupted, the electrolyte will 
 serve as a quenching bath. 
 
 Tempering. Also called letting down, drawing, drawing back, 
 draw-tempering and toughening. Tempering is always preceded 
 by some hardening operation, except in certain special cases where 
 hardening and tempering are combined in one operation. The 
 action which causes a high degree of hardening at the same time 
 produces a considerable amount of brittleness and concomitant 
 strain, and tempering signifies the mitigation or slight reduction 
 of the severity of the hardening operation for the purpose of 
 removing as much as possible of the brittleness and strain, without 
 affecting the hardness more than is unavoidable, leaving the steel 
 relatively hard and tough, instead of very hard and brittle. This 
 is the earliest and preferable meaning of tempering as employed 
 particularly for cutting tools and springs. The treatment 
 necessary consists in reheating to a tempering temperature from 
 about 200 to 300 C. (390 to 625 F.) depending upon the pur- 
 pose for which the material is intended. The heating may be 
 done in air or in some liquid, and the temperature may be 
 measured by a thermometer or a pyrometer, or, if in air, by the 
 oxide tints (temper colors or letting down tints) which form on a 
 surface freed from scale. The temperatures and names (assigned 
 by H. M. Howe) corresponding to the various colors are as follows: 
 
 Temper color Degrees C. Degrees F. 
 
 Pale yellow or straw color 220 428 
 
 Golden yellow 243 469 
 
 Purple : 277 531 
 
 Bright blue 288 550 
 
 Dark blue 316 601 
 
HEAT TREATMENT 23 1 
 
 It should be appreciated that these temper colors are due to the 
 thickness of the oxide film causing a corresponding interference 
 of light; hence holding for a longer period serves to cause a thicker 
 oxide film with a resulting change in appearance. The effect 
 of time on tempering, i.e., from holding at a given temperature 
 will depend somewhat upon the temperature itself and also the 
 degree of previous hardening. At lower temperatures the con- 
 dition of metastable equilibrium is more complete, therefore, the 
 tendency to normal equilibrium is greater. 
 
 The tempering may be effected in the case of small objects by 
 a heated plate (tempering plate) of cast iron or steel upon which 
 the objects are allowed to rest until they reach the desired tem- 
 perature. Blazing off, burning off, or oil flaring is a method of 
 tempering sometimes employed for springs, etc.; it consists in 
 heating the object coated with oil, either from the quenching 
 bath or otherwise, until it reaches a temperature just high enough 
 to cause the oil to burn readily in the air. 
 
 In James Horsfall's process for tempering steel wire for pianos, 
 etc., the wire was drawn to nearly the desired diameter, heated 
 to redness, and quenched in water or oil. It was then plunged 
 into molten lead; etc., until it had been sufficiently tempered, 
 after which the drawing was completed. For other special 
 methods of tempering see under Hardening (above) and Anneal- 
 ing (below). Pieces quenched in a bath, maintained at the tem- 
 perature to which they would otherwise be reheated if quenched 
 cold, are sometimes said to be mild tempered or quasi tempered. 
 
 Annealing. This term is commonly understood to mean a re- 
 heating operation followed by slow cooling to effect one or more 
 of the following objects: (a) completely undoing the effect of 
 hardening (either thermal or mechanical), leaving the steel in its 
 softest and most ductile condition: (6) removing any strains set up 
 by too rapid cooling, particularly if the rate has been different in 
 different parts of the piece: and (c) refinement of the grain. For 
 the first two it is sufficient if the annealing temperature is below 
 the lower critical point, say not over about 600 to 650 C. (ino 
 to 1200 F.), but for the last the temperature must be raised 
 to above the upper critical point, except in special treatments pre- 
 ceded by quenching as described below (for refining temperatures 
 see table on page 228). In the last case, also, the rate of cooling 
 must be slow until the temperature is below the critical range, 
 after which increasing the rate has no effect upon the hardening: 
 but as rapid cooling is liable to cause strains, particularly in 
 pieces which are large or of irregular form, it is generally slow. 
 At times, however, to hasten the operation, when the object has 
 become black in color it is plunged in water, which is termed 
 water annealing or negative quenching. Ordinarily in annealing 
 the temperature is carried to slightly above the critical point, to 
 obtain the benefit of all three results mentioned above. As there 
 is such a difference in the methods (and results) covered by ^ the 
 simple term annealing, it is customary to indicate more definitely 
 what kind is intended: ordinary or commercial annealing is a 
 term somewhat loosely used to mean reheating to some tern- 
 
23 2 HEAT TREATMENT 
 
 perature either slightly below or above the critical range followed 
 by slow cooling either in air or otherwise according to the size of 
 the object; where the material is to be rendered soft the terms 
 soft annealing, dead annealing or dead soft annealing are used; 
 the method of cooling may also be indicated, as air cooling, 
 furnace cooling or annealing, lime cooling or annealing, etc. 
 Where a substance such as lime or ashes is employed, the heated 
 article is buried in it and allowed to remain until cold or nearly 
 so; the same with furnace annealing. A form of annealing known 
 as normalizing consists in reheating to a temperature above the 
 critical range, holding at that temperature a certain length of 
 time, and then cooling in air: it is commonly used to secure uni- 
 form conditions on material treated in various ways or where, as 
 in the case of billets, the finishing temperature and amount of 
 hot working have resulted in a very coarse grain; this term was sug- 
 gested by Arnold, and equalizing was suggested by Stead as more 
 suitable but has not come into any extended employment. Flash 
 annealing or skin annealing is the name sometimes given to a 
 rapid heating operation designed to soften only the outer portion 
 or skin. Fine material, such as wire or thin sheets, is usually pro- 
 tected from the oxidation which would result if heated directly in 
 the air, by enclosing in a suitable metal box or pot: this is called 
 close annealing, box annealing, or pot annealing. The Jones 
 process consists in annealing in boxes or retorts in which a non- 
 oxidizing gas is maintained. In William Smith's process for 
 annealing wire before finishing, the heating was conducted in a 
 furnace in which a wall prevented the flame from striking the wire. 
 This was subsequently taken out and allowed to cool in oxide of 
 manganese, after which the drawing was completed. 
 
 Combined quenching and reheating operations are employed to 
 add to the advantage of annealing in securing high ductility with 
 almost complete absence of internal strains, those accruing from 
 quenching consisting in smaller grain and finer condition of pearl- 
 ite. These consist essentially of a quenching operation, the same 
 as for hardening, but not necessarily so vigorous, followed by a 
 reheating above what is employed for tempering as described 
 above. The first step (quenching) is sometimes designated as 
 grain refining treatment, and the second as tempering, although 
 toughening, drawing back, drawing, or reheating particularly 
 toughening are preferable to avoid confusion. The entire 
 operation is also commonly referred to as toughening, and to indi- 
 cate the quenching medium, the terms air toughening, water 
 toughening, or oil toughening are used (unfortunately these last 
 three terms are also used to indicate where hardened material is 
 tempered to about a yellow temper color and then cooled in the 
 give medium) . Annealing is also used in the same sense. Tough 
 hardening was the name suggested by Brinell for this treatment 
 as applied to mild steel. Double annealing was first suggested 
 by Wallerant (Wallerant's process) and consists of quenching in 
 water, oil, or other suitable medium from above the upper critical 
 point, followed by reheating to about 500 to 650 C. (930 to 
 1200 F.). Negative hardening (Osmond) is somewhat similar: 
 
HEAT TREATMENT HEATER 233 
 
 soft steel, if brittle, particularly from heating which has been too 
 long or at too high a temperature, is rendered much more tough 
 and ductile by heating to about 800 C. (1470 F.) and plunging 
 it into boiling water, no hardening ensuing. This term (and 
 negative quenching) is also used where the object is so large or 
 the medium so slow in its action (e.g., hot water, oil or molten 
 lead) that hardening in any degree does not result (see special 
 hardening processes). The Terre-Noire process for tempering 
 hoops, etc., consisted in (a) heating to a yellow (temper color) 
 heat, and plunging into oil: (b) reheating to a bright or a dull 
 cherry red and plunging again into oil. Various processes have 
 been devised for accelerating the rate of cooling through the 
 critical range. TschernofFs process consisted in cooling rapidly 
 until black, for small objects in air, for larger objects oil or water 
 depending upon the size, then finishing slowly so that during the 
 second stage the hardening would be undone and the severe 
 strains removed. In the Coffin axle process the axle is allowed to 
 cool at the ordinary rate and is then jeheated to just above the 
 upper critical point, quenched in oil until its temperature is at the 
 lower critical point, and then cooled in air. This treatment, 
 besides refining the grain, also renders the axle very much 
 tougher. In one experiment it was shown that the elastic limit 
 had been increased by this method over 46%, the tensile strength, 
 elongation, and reduction of area remaining nearly constant. 
 Coffin's rail process consists in immersing the rail in water, 
 immediately after leaving the rolls, until its temperature has fal- 
 len to the lower critical point, submerged jets of water playing 
 upon the thick head to equalize the rate of cooling. It is then 
 allowed to cool slowly in the air. Sandberg's process for rails is 
 very similar to Coffin's rail process, cold air being blown on the 
 head, after leaving the rolls. The Kennedy-Morrison process 
 was devised for the purpose of giving rails a finer structure, and 
 consisted in holding them on the tables a short time before the 
 last pass to give them a lower finishing temperature. But as the 
 reduction in the last pass is very slight, the effect obtained is also 
 slight. Garnaut and Siegfield's process for hardening and refin- 
 ing bars appears to be deserving of very little consideration. It 
 depends upon (a) forging a heated bar covered first with common 
 salt, and afterward with a miscellaneous mixture, (b) reheating 
 and rehammering, and (c) reheating and quenching in an aqueous 
 solution of various substances. 
 
 In commercial work the furnace charge for annealing is called 
 the annealing charge; for quenching, the quenching charge; 
 and for drawing back or toughening after quenching, the temper- 
 ing charge (sometimes also annealing charge). 
 
 Heat Treatment Crack. See page 222. 
 
 Heat Treatment, Effect of on Density. See pages 224 and 448. 
 
 Heat Unit. See page 199. 
 
 Heat of Vaporization. See page 202. 
 
 Heat Weight. See page 201. 
 
 Heater. (i) The man in charge of a heating furnace; (2) a piece of 
 preheated iron laid upon an object at the part where it is to be 
 
234 HEATH PROCESS HEYN'S REAGENTS 
 
 bent when it cannot be heated in a furnace direct; it is also used 
 
 for skin-drying molds (Eng.). 
 Heath Process. See page 113. 
 Heathfield Process. See page 371. 
 Heating Coke. See page 97. 
 Heating Crack. See Crack. 
 Heating Curve. See Curve. 
 Heating Curve Method. Of determining critical points: see page 
 
 265. 
 
 Heating Furnace. See page 184. 
 Heating Furnace Cinder. See Slag. 
 Heating Methods of Etching. See pages 286 and 288. 
 Heaton Process. See page 386. 
 Heavy Alloy. See Alloy. 
 Heavy Metal. See Alloy. 
 Heberlein Pot. See page 44. 
 Heerzeel and Paulis Process. See page 386. 
 Helfenstein Furnace. See page 158. 
 Helsby Method. See page 503. 
 Helve. See Hammer. 
 
 Hematite. (i) Iron ore: see page 243; (2) pig iron: see page 344 
 Hemicrystalline Crystal. See page 122. 
 Hemihedron. See page 122. 
 Hemimetamorphosis. See page 122. 
 Hemipelic Structure. See page 125. 
 Hemiprismatic System. Of crystallization: see page 120. 
 Hemitrope. See page 124. 
 
 Hen and Chickens Method. Of Casting: see page 6r. 
 Henderson Process. See page 386. 
 Henning's Spectral Pyrometer. See page 208. 
 Heraus Furnace. See page 158. 
 Bering Furnace. See page 158. 
 Heroult Furnace. See page 159. 
 Hess's Law. See page 200. 
 Heterocellular Structure. See page 126. 
 Heterochrome Photometer, Nordman's. See page 208. 
 Heterogeneous; Heterogeneity. Not of the same composition 
 
 throughout; not uniform. 
 
 Heterogeneous Distribution of Carbon. See page 2T3. 
 Heterogeneous Equilibrium. See page 328. 
 Heterogeneous Steels. See Homogeneous Steels. 
 Heterogeneous System. See page 327. 
 Heteromorphic. See page 122. 
 Heterotomous. See page 124. 
 Heussler Alloys. See Alloy. 
 Hewitt Process. See page 380. 
 Hexad. See page 86. 
 
 Hexagonal System. Of crystallization: see page 120. 
 Hexahedrite. See page 292. 
 Hexavalent. See page 86. 
 
 Heyn and Baux's Method. For sulphur prints: see page 288. 
 Heyn's Reagents. For etching: see page 287. 
 
HIBBARD METHOD HOLOAXIAL 235 
 
 Hibbard Method. For fluid compression: see page 63. 
 
 High Bloomary. See page 142. 
 
 High Boil. See page 376. 
 
 High Carbon Steel. See page 455. 
 
 High Furnace (rare). Blast Furnace. 
 
 High Gage. See page 186. 
 
 High Grade. Sometimes used for high carbon. 
 
 High Grade Fireclays. See page 396. 
 
 High Heat Tools. See page 446. 
 
 High Heat Treatment. In Taylor- White process: see page 446. 
 
 High Phosphorus Steel. Steel containing a considerable percent- 
 age of phosphorus, or more than is permitted by the given speci- 
 fication. 
 
 High Pressure Combustion. Using forced draft. 
 
 High Range Mercury Thermometer. See page 205. 
 
 High Resistance Steel. See page 443. 
 
 High Silicon Iron; Pig. See pages 344 and 354. 
 
 High Silicon. Softener. See page 347. 
 
 High Speed Steel ; Tool Steel. See page 446. 
 
 High Sulphur Steel. Steel containing a considerable percentage of 
 sulphur, or more than is permitted by the given specification. 
 
 High Temper Steel. See Temper. 
 
 High Tension Steels. See page 443. 
 
 Hilgenstock Process. See page 386. 
 
 Hilpert and Colver-Glauert's Reagent. For etching: see page 287. 
 
 Hinsdale Process. (i) For casting: see page 62: (2) for fluid 
 compression: see page 63. 
 
 Hiorth Furnace. See page 160. 
 
 Hobson Pyrometer. See page 209. 
 
 Hoerde Process. See page 386. 
 
 Hofer Process. See page 141. 
 
 Hoist. See page 33. 
 
 Holborn Gas Pyrometer. See page 207. 
 
 Holborn-Kurlbaum Optical Pyrometer. See page 207. 
 
 Holborn and Wien Pyrometer. See page 208. 
 
 Hold the Heat. See page 314. 
 
 Hole. (i) Of a crucible furnace: see page 114 ; (2) in wire drawing: 
 see page 507. 
 
 Hole Furnace. See page 114. 
 
 Holland Process. See page 73. 
 
 Holley Movable (Removable) Bottom. See page 17. 
 
 Hollow. Of steel, seamy or laminated. 
 
 Hollow Fire. See page 79. 
 
 Hollow Forging. See Forging. 
 
 Hollow Pressed Axle. See Mercader Hollow Pressed Axle. 
 
 Hollow Roll. See page 404. 
 
 Holloway Process. A method for reducing metallic sulphides by 
 blowing air through them whole molten (Bessermerizing), the 
 sulphur acting as the fuel to supply the necessary heat; not a 
 success for sulphides of iron. 
 
 Holo- (prefix). See page 122. 
 
 Holoaxial. See page 122. 
 
236 HOLOCRYSTALLINE HOT BLAST PYROMETER 
 
 Holocrystalline. See page 122. 
 
 Holohedral. See page 122. 
 
 Holoisometric. See page 122. 
 
 Holosiderite. See page 291. 
 
 Holosymmetric. See page 122. 
 
 Holsters. See page 403. 
 
 Homocellular Structure. See page 126. 
 
 Homoeomorphism. See page 121. 
 
 Homogeneity Test. See page 476. 
 
 Homogeneous Distribution of Carbon. See page 213. 
 
 Homogeneous Equilibrium. See page 328. 
 
 Homogeneous Metal (obs.). A name formerly applied to crucible 
 or other steel, made in a molten condition, in contradistinction 
 to the heterogeneous condition of blister steel. -'y; 
 
 Homogeneous Nickel Steel Armor Plate. See page 8. 
 
 Homogeneous Steel (obs.). (i) Used occasionally to distinguish 
 from casehardened or cemented steels; of same composition (par- 
 ticularly carbon) throughout; in this connection casehardened 
 or cemented steels might be termed heterogeneous steels; (2) 
 free from blowholes, solid; (3) a variety of crucible steel easily 
 bent and worked. 
 
 Homogeneous System. See page 328. 
 
 Homogenize. See page 328. 
 
 Homohedral. See page 122. 
 
 Honeycombed. See page 55. 
 
 Hooke's Law. See page 334. 
 
 Hooked Fracture. See page 178. 
 
 Hoop. See Coil. 
 
 Hoop Mill. See page 415. 
 
 Hopper. A door or trap at the bottom of a chute or shaft by 
 means of which the contents can be dumped out or their descent 
 regulated: see also page 32. 
 
 Horizontal Heating Furnace. See page 184. 
 
 Horizontal Regenerators. See page 312. 
 
 Horizontal Testing Machine. See page 469. 
 
 Horn. See page 430. 
 
 Horse. See Salamander. 
 
 Horseshoe Iron. See page 378. 
 
 Horsfall Process. See page 231. 
 
 Hot. (i) Of pig iron in the molten or fluid condition; molten metal; 
 (2) of steel when it is hot enough for rolling or forging, or when it 
 is finished at a high temperature; (3) of working, when metal is 
 heated, in contradistinction to cold working. 
 
 Hot Bed. See page 414. 
 
 Hot Bend Test See page 476. 
 
 Hot Blast. See Blast. 
 
 Hot Blast Charcoal Iron. See page 343. 
 
 Hot Blast Cupola. See page 182. 
 
 Hot Blast Furnace. See page 39. 
 
 Hot Blast Iron; Pig.' Pig iron smelted with hot blast. 
 
 Hot Blastman. See page 38. 
 
 Hot Blast Pyrometer. See page 210. 
 
HOT BLOW HYDRAULIC FORGING 237 
 
 Hot Blow. See page 20. 
 
 Hot Blowing Iron; Metal; Pig. See page 20. 
 
 Hot Crack. See Crack. 
 
 Hot Drawn. Of tubes : see page 491. 
 
 Hot Ductility. See page 331. 
 
 Hot Etching. See page 286. 
 
 Hot Flame Weld. See page 503. 
 
 Hot Forging. Used only in contradistinction to cold working. 
 
 Hot Galvanizing. See page 370. 
 
 Hot Hanging. Of a blast furnace: see page 35. 
 
 Hot Iron. See pages 20 and 343. 
 
 Hot Jacket. See page 36. 
 
 Hot Junction. Of a thermocouple: see page 209. 
 
 Hot Melting. See page 376. 
 
 Hot Metal. Pig iron from the blast furnace before it has solidified; 
 also called direct metal, more particularly in the sense that it is 
 to be used in this condition in some refining process. 
 
 Hot Punching. See Forging. 
 
 Hot Rolling. Used only in contradistinction to cold working. 
 
 Hot Saw. A circular power saw for cutting hot steel. 
 
 Hot Scaffold. See page 35. 
 
 Hot Scale. A scale for weighing material while hot. 
 
 Hot Short; Shortness. See Brittleness. 
 
 Hot Spot. See pages 36 and 58. 
 
 Hot Stable State. See page 327. 
 
 Hot-top Sinkhead. See page 56. 
 
 Hot Water Hardening. See page 229. 
 
 Hot Working. Working metal after heating it to a suitable tem- 
 perature, in contradistinction to working it cold. 
 
 Housing; Housing Cup; Pin; Screw. See page 403. 
 
 Howe's Formulae. For elongation: see page 338. 
 
 Howell Mill. See page 434. 
 
 Hudson (J. J.) Process. See page 77. 
 
 Hughes (Wm. B.) Process. See page 318. 
 
 Humbert Process. See page 159. 
 
 Humfrey's Amorphous Iron Theory. Of hardening: see page 281. 
 
 Humid Analysis; Process. See page 82. 
 
 Hunch Pit. See page 316. 
 
 Hungry. Of pig iron rich in silicon and phosphorus; if used for 
 puddling it requires more ore or oxides for their oxidation and 
 removal. 
 
 Hunt Process. See page 380. 
 
 Huntington-Heberlein Pot Process. See page 44. 
 
 Huntsman Process. See page 113. 
 
 Huntsman Steel (obs.). Crucible steel, after the inventor, Benja- 
 min Huntsman (1746). 
 
 Husgafvel's High Bloomary. See page 142. 
 
 Huth Process. See page 62. 
 
 Hyaloid (rare). Glassy or transparent. 
 
 Hdraesfer Process. See page 369. 
 
 Hydrate Ore. See page 244. 
 
 Hydraulic Forging. See Forging. 
 
238 HYDRAULIC PRESS HYSTERESIS GAP 
 
 Hydraulic Press. See Press. 
 
 Hydraulic Shears. See page 412. 
 
 Hydrochloric Acid. For etching: see page 287. 
 
 Hydrogen. H; at. wt., i; melt, pt., -257 C. (-431 F.); boil, 
 pt, 253 C. (423 F.); sp. gr., 0.0695 (air = i); i liter weighs 
 0.089873 gram, called i crith. It is a colorless, odorless, and 
 tasteless gas, and is the lightest substance known. It has a 
 powerful affinity for oxygen and, in combination with it, occurs 
 as water. It is absorbed or occluded by iron to a considerable 
 extent, and tends to make the metal brittle. 
 
 Hydrogen Company's Process. See page 370. 
 
 Hydrogen Point. See page 264. 
 
 Hydrogen Theory. Of passivity: see page 364. 
 
 Hydrohematite. See page 244. 
 
 Hydro-metallurgy. Pyro-metallurgy, q.v. 
 
 Hydrometer. An instrument for measuring the specific gravity of 
 liquids, consisting of a graduated tube, one end of which is loaded 
 so the tube will remain upright. 
 
 Hydro -Pyrometer. See page 207. 
 
 Hydrosiderum (obs.). Or wassereisen; names suggested by Mayer 
 (1782) for phosphide of iron which he discovered in pig made from 
 bog ore, and which, at the time, he thought was a new metal. 
 
 Hydrothermal Fusion. See page 201. 
 
 Hygrometer. An instrument for measuring the percentage of 
 moisture in gases, more particularly air; there are various types. 
 
 Hygrometric Moisture ; Water. See Water. 
 
 Hygroscopic. Having an affinity for moisture. 
 
 Hygroscopic Moisture. See Water. 
 
 Hyper- (prefix). In chemistry: see page 88. 
 
 Hyper-aeolic Steel. See page 273. 
 
 Hyper-eutectic Cast Iron. See page 271. 
 
 Hyper-eutectic Steel. See page 271. 
 
 Hyper-eutectoid Steel. See page 273. 
 
 Hypertectic. See page 269. 
 
 Hypertectic Point. See page 269. 
 
 Hypo- (prefix). In chemistry: see page 88. 
 
 Hypo-aeolic Steel. See page 273. 
 
 Hypo-eutectic Alloys. See page 271. 
 
 Hypo-eutectic Cast Iron. See page 271. 
 
 Hypo-eutectic Steel. See page 271. 
 
 Hypo-eutectoid Steel. See page 271. 
 
 Hysteresis. Retardation of magnetization (magnetic hysteresis). 
 The persistency with which certain bodies tend to retain their 
 previous condition. Professor Ewing uses the word in a more 
 general sense of a dissipation of energy occurring in any cycle of 
 operations (I. A. T. M.), see pages 269 and 327,^ 
 
 Hysteresis Gap; Temperature, See page 265, 
 
'.. Chemical symbol for iodine: see page 84. 
 
 ii. Chemical symbol for indium: see page 84. 
 
 r. Chemical symbol for indium : see page 84. 
 
 !. A. T. M. International Association for Testing Materials. 
 
 !. A. T. M. Iron-Carbon Diagram. See page 271. 
 
 !. D. Inside diameter. 
 
 [. E. E. Institute of Electrical Engineers (Eng.). 
 
 -ic (suffix), In chemistry: see page 88. 
 
 ide (suffix). In chemistry: see page 88. 
 
 ideal Gas. See Gas. 
 
 idiomorphic Crystal. See page 122. 
 Idle Roller; Idler. See page 407. 
 Igewsky's Reagent. For etching: see page 287. 
 Igneous Fusion. See page 201. 
 Ignition; Ignition Point. See page 202. 
 Illingworth Method. See page 63. 
 Illumination; Illuminator. See page 285. 
 Ilmenite. See page 245. 
 Image. See page 285. 
 Imbricated Structure. See page 126. 
 Immiscible. Incapable of mixing. 
 
 Impact. (i) General: see page 333 r (2) coefficient of: see page 481. 
 Impact Crushing Tests. See page 481. 
 Impact Energy. See page 481. 
 Impact Shear Test. See page 482. 
 Impact Stress. See page 333. 
 Impact Test. See page 481. 
 Imperatori Process. See page 142. 
 Imperfect Cleavage. See page 124. 
 Imperfect Elasticity. See page 330. 
 Imperfection. Defect. 
 Imperial Wire Gage. See page 188. 
 
 Impregnation. The absorption or combination of one substance 
 with another, e.g., the impregnation of iron with carbon; some- 
 times used in the sense of absorbing all possible. 
 Impregnation Zone. See page 293. 
 Improved Wire. See page 509. 
 
 Impurity. A substance contaminating, or detracting from the 
 purity of, another substance. It is a mechanical or a chemical 
 impurity depending upon whether it is simply intermixed or is 
 chemically combined. 
 
 In Blast. Of a blast furnace: see page 37, 
 Inactive Iron. See page 364. 
 Incandescent. Glowing with intense brilliance, e.g., incandescent 
 
 carbon is carbon at a white heat. 
 Incandescent Welding. See page 503. 
 Incipient Combustion. See page 202. 
 
 239 
 
240 INCIPIENT FUSION INTEGRAL RADIATOR 
 
 Incipient Fusion, Zone of. See page 36. 
 
 Inclusion. Something included or enclosed in a substance, such as 
 gas or mechanically suspended foreign matter: see page 57. 
 
 Incompatibility Theory. See page 289. 
 
 Incomplete Combustion. See page 202. 
 
 Incomplete Crystal. See page 122. 
 
 Incomplete Equilibrium. See page 326. 
 
 Incomplete Heterogeneous Equilibrium. See page 327. 
 
 Incomplete Purification. Not carried to its greatest possible extent, 
 as in pig washing. 
 
 Incongruent Freezing. See page 267. 
 
 Index. Of corrosion: see page 107. 
 
 Indian Steel. See Wootz. 
 
 Indifferent Equilibrium. See page 327. 
 
 Indirect Heating Furnace. See page 181. 
 
 Indirect Processes; Recovery Processes. In the manufacture of 
 coke: see page 96. 
 
 Indirect Resistance Heating. See page 153. 
 
 Indistinct Cleavage. See page 124. 
 
 Individual Deviation. Of slipping: see page 283. 
 
 Induction Furnace; Heating. See page 153. 
 
 Indurate; Induration. To harden; hardening. 
 
 Inequiaxed Crystal; Grain. See page 217. 
 
 Inequilibrium. See page 326. 
 
 Inert Gas. See page 70. 
 
 Influence of Time. On grain size: see page 214. 
 
 Infusion Method of Hardening. See page 69. 
 
 Infusorial Earth. See page 396. 
 
 Ingate. See page 299. 
 
 Ingot. See page 53. 
 
 Ingot Crack. A crack in the side of an ingot formed during cooling. 
 
 Ingot Iron. (i) The term formerly suggested for iron products low 
 in carbon produced in a molten condition; still employed in some 
 foreign countries in this sense; (2) a trade name for open hearth 
 steel low in carbon and impurities. 
 
 Ingot Metal. (i) Metal cast in ingots; (2) ingot iron. 
 
 Ingot Nickel. See- page 353. 
 
 Ingot Steel (rare). Medium or high carbon steel cast in ingots. 
 
 Ingot Tumbler.' A receptacle mounted on a buggy to convey ingots 
 from the soaking pits to the rolling mill. It is arranged to spill 
 and tip the ingot out when it reaches the roll table. 
 
 Ingotism. See page 57. 
 
 Initial Stress. See page 333. 
 
 Inoculation. See page 268. 
 
 Inorganic Chemistry. See page 82. 
 
 Inoxidizing Coating; Process. See page 362. 
 
 Inset Sprue. See page 299. 
 
 Inside Gage. See page 186. 
 
 Insuluminum. See page 372. 
 
 Intake. (i) The place where the gas enters a furnace; (2) in hy- 
 draulic wqrk, where water enters a construction. 
 
 Integral Radiator. See page 267. 
 
INTENSITY OF STRESS I ONID 241 
 
 Intensity of Stress. See page 333. 
 
 Intercrystalline Rupture. See page 123. 
 
 Intergranular Cement. See page 281 . 
 
 Intergranular Deformation; Flow. See page 281. 
 
 Intergranular Fracture. See page 178. 
 
 Intergranular Motion. See page 282. 
 
 Interior Shrinkage. See page 54. 
 
 Intel-metallic Alloy; Compound. See Alloy. 
 
 Intermittent Brittleness. See Brittleness. 
 
 Internal Crack. See Crack. 
 
 Internal Crystal. See page 127. 
 
 Internal Defect. See page 333. 
 
 Internal Fissure. See Crack. 
 
 Internal Force. See page 332. 
 
 Internal Fracture. See pages 179 and 333. 
 
 Internal Friction. See page 267. 
 
 Internal Orientation. See page 127. 
 
 Internal Rupture. See pages 333 and 491. 
 
 Internal Strain; Stress. See pages 281 and 332. 
 
 Internal Surface of Weakness. See page 283. 
 
 Internal Tension. See page 281. 
 
 Internally Blown Converter. See page 19. 
 
 Interpenetration. A general term for those actions by which one 
 
 portion of matter is distributed either wholly or in part through a 
 
 space containing matter generally of a different kind (I. A. T. M.) : 
 
 see page 124. 
 
 Interpolation. See Curve. 
 Interrupted Cleavage. See page 124. 
 Interstrain; Interstrain Theory. In connection with hardening: 
 
 see page 281. 
 
 Interstratal Movement. See page 282. 
 Intimate Mixture. See page 83. 
 Intra-crystalline Fracture. See page 1 78. 
 Intra-crystalline Rupture. See page 123. 
 Intra -granular Flow. See page 281. 
 Latra-pearlitic Flow. See page 281. 
 
 Intrusion. Material forced into a cavity from the surrounding wall. 
 Intumescence. Particularly of certain crystals on heating; swelling 
 
 up. 
 
 Invar. See page 451. 
 Invariant System. See page 327. 
 Inverse Ratio. In testing: see page 475. 
 Inversion. See page 271. 
 
 Inversion Temperature. See pages 108 and 327. 
 Inverted Molds. See page 59. 
 Invisible. A name given by H. M. Howe to the condition when the 
 
 interior of a furnace or crucible and the bodies contained in it are 
 
 at the same temperature, and the bodies are therefore invisible. 
 Inwall. See page 32. 
 
 Iodine. One of Osmond's reagents: see page 287. 
 Ion; Ionic Dissociation; Theory. See page 89. 
 lonid. See page 89. 
 
 16 
 
242 IRELAND PROCESS IRON OCHRE 
 
 Ireland Process. See page 142. 
 Irestone. See page 243. 
 Iridescent Ore. See page 244. 
 
 Irish Temper. See Temper. 
 Iron. Pig iron, q.v. 
 
 Iron. Fe; at. wt., 56; melt, pt, 1505 C. (2741 F.); sp.gr., 7.84 
 to 8.139. It is rarely found in the metallic condition in nature 
 except as meteorites (q.v.); its chief occurrence is in combination 
 with oxygen (see Iron Ore). The pure metal has a white lus- 
 trous appearance, does not harden appreciably on quenching, 
 and is strongly attracted by a magnet, although it cannot itself be 
 made magnetic except when containing carbon, or while an elec- 
 tric current is passed around it. The pure metal is merely a 
 metallurgical curiosity. Nearly pure iron is now regularly pro- 
 duced electrolytically (see Electrolytic Iron). In certain cases 
 combinations of iron and oxygen act as an acid to form salts. 
 The 'derivatives of the hypothetical ferrous acid, H 2 Fe 2 O4, are 
 termed ferrites, e.g., ZnFe 2 O4, zinc ferrite; another hypothetical 
 acid, ferric acid (H 2 FeO4) forms salts known as ferrates. For 
 producing pure iron Peligot's method was to reduce heated fer- 
 rous chloride with hydrogen, while in PommarSde's method zinc 
 was substituted for hydrogen. 
 
 Irons. See page 291. 
 
 Iron of Bessemer. Name suggested for iron or low carbon steel 
 made by the Bessemer (pneumatic) process. 
 
 Iron Blast Furnace (rare). Used only to distinguish it from a cop- 
 per or a lead blast furnace. 
 
 Iron Blower. See page 492. 
 
 Iron Cancer. See page 106. 
 
 Iron-Carbide Solution. In hardening: see page 281. 
 
 Iron-Carbon Diagrams; System. See page 271. 
 
 Iron Carbonyl. See Carbon. 
 
 Iron-Cementite Diagram. See page 271. 
 
 Iron Change. An allotropic change occurring in the condition of 
 iron. 
 
 Iron Company's Process. See page 138. 
 
 Iron Glance. See page 243. 
 
 Iron Glass. See page 292. 
 
 Iron-Graphite Diagram. See page 271. 
 
 Iron Hardenite. See page 275. 
 
 Iron Hat. See page 245. 
 
 Iron-Iron Hydroxide Eutectic. See page 265. 
 
 Iron Ladle. See Ladle. 
 
 Iron Man (Eng.). A name given by workmen to certain mechan- 
 ical devices which replace hand labor, such as charging machines 
 or mechanical puddlers: see page 379. 
 
 Iron Meteorite. See page 291. 
 
 Iron Mine. See page 243. 
 
 Iron Mold. See page 296. 
 
 Iron Nitride. See page 279. 
 
 Iron Notch. See page 32. 
 
 IronOchre. See page 244. 
 
IRON ORE 243 
 
 Iron Ore. See also Ore. Rarely called (Eng.) ironstone, iron 
 mine, or irestone. Iron ores, as a rule, contain from 25 to 70 % 
 of iron; if less than 40% they must first be concentrated (part of 
 the gangue removed), and if less than 25% they cannot be con- 
 sidered commercially, as the cost of smelting is too great. Concen- 
 tration may consist in washing, i.e., employing water to effect a 
 separation according to the relative specific gravities, or, in the case 
 of magnetic ores, by some form of magnetic separation, the iron 
 being attracted by a magnet while the gangue is unaffected; in 
 both cases the ore must be in a moderately fine condition. In 
 the case of carbonates, or ores containing carbonaceous matter, 
 roasting is resorted to. At the present time in this country the 
 ores as mined average slightly over 50%, the Lake ores running 
 higher than those in the South, sometimes over 60%. In con- 
 sidering the iron minerals a division is made according to whether 
 or not they are available for the iron industry. Iron ores may 
 be classified as follows : 
 
 I. Chemical composition : 
 
 1. Oxide. 
 
 2. Carbonate. 
 
 3. Arsenide. 
 
 4. Chromate. 
 
 5. Phosphate. 
 
 6. Sulphide. 
 6. Titanate. 
 
 8. Tungstate. 
 
 II. Phosphorus content (practically all the phosphorus is 
 reduced in making pig iron): will yield pig containing: 
 
 9. Not over 0.1% of phosphorus: Bessemer ore, acid 
 Bessemer ore (rare), hematite (Eng.). 
 
 10. Over o.i % of phosphorus: non-Bessemer ore, basic 
 Bessemer ore (foreign); cold short ore (Eng.). , 
 
 III. Nature of the gangue : 
 
 11. Silicious ore: high silica. 
 
 12. Dry ore (Eng.): low silica. 
 
 13. Calcareous ore: nigh lime and bases. 
 
 14. Red short ore : high sulphur. 
 
 15. Self- fluxing ore: where the proportion of lime, mag- 
 nesia, alumina, and silica are such that no addition (or 
 very little) of flux is needed for smelting. 
 
 1 6. Self-roasting ore: where sufficient carbonaceous 
 matter is present for roasting without the necessity 
 for extraneous fuel. 
 
 Commercial ores : 
 
 Oxides. (i) Anhydrous ferric oxide, Fe 2 O3, containing when 
 pure 70% Fe. ^ In color it varies from a brilliant black to a brick 
 red. It is ordinarily known as hematite, haematite (Eng.), red 
 hematite, or red iron ore; more rarely as red iron mine (Eng.), 
 red mine stone (Eng.), bloodstone, or red slag ironstone (Eng.). 
 On account of certain characteristics the following names are 
 sometimes used: specular iron ore or iron glance, when black and 
 
244 IRON ORE 
 
 lustrous; iridescent ore, also lustrous, but having peacock colors, 
 and may be hematite or limonite; micaceous hematite, or mica- 
 ceous iron ore, a pure form, usually gray in color, and having a 
 scaly structure; oolitic ore, having the appearance of fish eggs, 
 consisting of particles of sand or limestone covered with ferric 
 oxide, either anhydrous or hydrated; pisolitic ore, where the par- 
 ticles are of slightly larger size; fossil ore, fossiliferous red hema- 
 tite, or red fossil ore, often self-fluxing; kidney ore or reniform 
 iron ore, having the shape of kidneys; frondescent hematite, hav- 
 ing a radiating structure; martite, pseudomorphous after mag- 
 netite; rubble ironstone, having a conglomerate structure. 
 
 Oxides. (2) Hydrated ferric oxide, Fe 2 O 3 -nH 2 O (the various 
 names employed do not always indicate a definite percentage of 
 water). They vary in color from a light yellow to a dark black- 
 ish brown, and may be soft and pulverulent or hard and compact : 
 Limonite, goethite, brown hematite, brown iron ore, bog ore, 
 bog iron ore or lake iron ore (Sweden); turgite or hydrohematite 
 is a variety usually classed as limonite. On account of their 
 shape, varieties are sometimes called bean ore, pipe ore, or 
 milk'olithic ore (granulated). 
 
 Oxides. (3) Magnetic oxide, Fe 3 O 4 (FeO, Fe 2 Oi), contain- 
 ing when pure 72.4% Fe; a black hard mineral occurring in 
 large masses or granulated, and strongly attracted by a magnet: 
 magnetite, magnetic iron ore, lodestone, black iron sand, iron 
 sand, or ologist ore. 
 
 Carbonates. FeCO 3 , when pure containing 48.3% Fe, 
 usually roasted to drive off the carbonic acid, when a mixture of 
 . ferrous and ferric oxides results; occurs usually in granular 
 masses of a gray or brown color; commonly called siderite, 
 spathic ore, spathic iron ore; rarely sparry ore, sperry ore, 
 spathic carbonate, chalybite, sphaerosiderite, brown ore, or 
 white ironstone; on account of certain characteristics the fol- 
 lowing names have been applied: black band (Eng.) or pottery 
 mine (North Staffordshire), contains coal and occasionally 
 some limestone; argillaceous siderite, argillaceous iron ore, clay 
 band (Eng.), clay band ironstone (Eng.), or clay ironstone (Eng.), 
 contains considerable amounts of clay. 
 
 Minerals which have little, if any, application as a source of 
 iron: 
 
 Arsenide. Leucopyrite or lollingite is an arsenide of varying 
 composition, sometimes containing nickel, etc.; scorodite is a 
 combination of ferric oxide, arsenic oxide, and water. 
 
 Chromates. Chromite, chromic iron, or chrome iron ore, 
 FeO, Cr 2 O 3 , is a massive black mineral resembling magnetite; it is 
 very infusible and is used as a refractory (q.v.) ; it is the principal 
 source of chromium. 
 
 Phosphates. Vivianite or blue iron earth is a ferric phosphate. 
 
 Oxides. Franklinite, dodecahedral iron ore, or mangano- 
 magnesian magnetite, is an oxide of iron in combination with 
 zinc (of which it is a source) and manganese; it is a hard black 
 mineral resembling magnetite. Ochre, iron ochre, or red ochre 
 are oxides occurring in an earthy pulverulent condition, and are 
 
IRON OXIDE IRREGULAR CONTRACTION 245 
 
 used principally as paints. Gossan, Gozzan, or iron hat is a 
 hydrated oxide of iron forming the cap of deposits of copper 
 pyrites due to the mineral having been decomposed (weathered) 
 and the copper leached out. Laterite is a hydrated oxide of iron 
 occurring in India; it is soft when cut, becoming hard on exposure, 
 and is used principally for making bricks. 
 
 Sulphides. Iron pyrites, pyrite, or yellow pyrites has the for- 
 mula FeS 2 ; when burned in the manufacture of sulphuric acid the 
 residue, consisting of ferric oxide containing an extremely small 
 percentage of phosphorus, is sometimes used in the production of 
 low phosphorus pig, and is known as purple ore or blue billy. 
 Marcasite or white iron pyrites has the same formula as pyrite, 
 but differs in crystalline form. Arsenopyrite or mispickel has 
 the formula FeAsS. Pyrrhotite, magnetic pyrites, or mundic is a 
 combination of various sulphides of iron, and usually contains 
 nickel, of which it is an important source. Copper pyrites or 
 chalcopyrite is a sulphide of iron and copper, used as an ore of 
 copper. Melanterite or copperas is crystallized ferrous sulphate, 
 
 Titanates. Ilmenite, menaccpnite or titanic iron ore is com- 
 posed of oxides of iron and titanium; it is used to a limited extent 
 as an ore of iron. 
 
 Tungstates. Wolframite is a tungstate of iron and manganese 
 and is the principal ore of tungsten. 
 
 Manganese Ores. The dividing line between manganiferous 
 iron ores and manganese ores was formerly taken at 44% Mn. 
 Later, ores with as little as 40% Mn have been termed man- 
 ganese ores, and those below this figure, manganiferous ores. 
 The following classification was proposed in "Memoirs of the 
 Geological Survey of India," 1909, and is applicable to all ores 
 containing over a combined total for manganese and iron of 50%: 
 
 Mn% Fe% 
 
 Manganese Ores .................... 40 to 63 o to 10 
 
 Ferruginous Manganese Ores ......... 25 to 50 10 to 30 
 
 Manganiferous Iron Ores ............ 5 to 30 30 to 65 
 
 Iron Ores .......................... o to 5 45 to 70 
 
 Ores of Steel was an old name applied to ores considered 
 especially suited for the manufacture of wrought steel (as distin- 
 guished from wrought iron). 
 
 Iron Oxide. See pages 279 and 396. 
 
 Iron Phosphide. See page 279. 
 
 Iron-Phosphorus Diagram. See page 272. 
 
 Iron Pyrites. See above. 
 
 Iron of Reaumur. Name suggested for malleable cast iron. 
 
 Iron Sand. (i) Ore: see page 243; (2) in molding: see page 296. 
 
 Iron Side. Of a converter: see page 18. 
 
 Iron Silicate ; Silicide. See page 279. 
 
 Ironstone ; Ironstone Meteorite. (i) Ore: see page 243; (2) meteor- 
 ite: see page 291. 
 
 Iron Sulphide. See page 279. 
 
 Irregular Contraction. See page 222. 
 
246 IRREGULAR FRACTURE IZOD TEST 
 
 Irregular Fracture. See page 179. 
 
 Irreversible Alloy ; Process ; Transformation. See pages 265 and 
 
 327- 
 
 Irritant. A term proposed by Dumas to describe the action of spe- 
 cial elements present in iron alloys, chiefly the metals nickel, 
 manganese, chromium, and tungsten, though silicon, a non-metal, 
 could be added namely, that they were irritants to the non- 
 metal carbon. These metals were, generally speaking, not power- 
 ful in themselves, but only when carbon was present. 
 
 Irving Furnace ; Process. See pages 142 and 160. 
 
 Ischewski's Reagent. For etching: see page 287. 
 
 Isobar. The line in a diagram showing equal barometric pressure. 
 
 Isocarb. The line in a diagram showing equal carbon content. 
 
 Isodictyal Structure. See page 126. 
 
 Isodimorphism. See page 121. 
 
 Isolated Crystal. See page 123. 
 
 Isolation. In cementation : see page 70. 
 
 Isomer ; Isomeric ; Isomeride ; Isomerism. See pages 85 and 86. 
 
 Isometric System. Of crystallization: see page 120. 
 
 Isomorphism. See page 121. 
 
 Isomorphous Mixture. See page 270. 
 
 Isophos. The line in a diagram showing equal phosphorus content. 
 
 Isothei. The line in a diagram showing equal sulphur content. 
 
 Isotherm. The line in a diagram showing equal temperature. 
 
 Isothermal Freezing. See page 267. 
 
 Isothermal Transformation. See page 327. 
 
 Isotropic ; Isotropy. See page 330. 
 
 Italian Process. See page 141. 
 
 -ite (suffix). In chemistry: see page 88. 
 
 Izod Test. See page 482. 
 
J. 
 
 J. de P. Gage. See page 188. 
 Jack Shaft. See page 407- 
 
 Jacket. (i) The iron sheathing of a furnace; (2) the brick covering 
 of a boiler. 
 
 aggar Hardness Test. See page 480. 
 
 'amb Coke. See page 97. 
 
 'apan Lacquer. See page 365. 
 
 ar Machine. See page 301. 
 _"arolimek Process. See page 229. 
 Jemmy (Eng.). A short crowbar. 
 Jenkins (C. F.) Process. See page 373. 
 ~ig. See Ore. 
 
 ob Pyrometer. See page 209. 
 
 ockey Weight. Of a testing machine: see page 469. 
 
 og Jogless. See Curve. 
 
 ohnson Elastic Limit. See page 470. 
 
 ohnson Process. For spheroidizing graphite: see page 38. 
 
 oint. See page 502. 
 
 'oint Board. See page 297. 
 
 oint Foliation. See page 1 24. 
 
 i oint Strength. See page 282. 
 Joist. A name rarely used for a beam or I-beam. 
 
 oly Meldometer. See page 207. 
 
 ones and Jones Process. See page 380. 
 
 "ones Mixer. See Mixer. 
 
 ones Process. (i) For fluid compression: see page 63; (2) of heat 
 treatment: see page 232; (3) step process: see page 142. 
 
 ones' Reagent. For etching: see page 287. 
 
 'osserand and Jacquet Process. See page 418. 
 
 'ournal. Of a roll: see page 403. 
 
 "limbo. The cooler for the cinder notch of a blast furnace. 
 
 ump. (i) In blast furnace practice: see page 35; (2) in connec- 
 tion with sheets: see page 430; (3) in welding: see page 502; (4) 
 to upset, as the end of a bar. 
 Jumper (Eng.). Also called monkey; (i) a dolly, q.v.; (2) the 
 
 sparks from a ladle of cast iron. 
 
 Jump Up (Eng.). Upsetting a bar, etc., or increasing the cross- 
 section by striking it on the end. 
 Junction Shaft (obs.). A spindle in a rolling mill. 
 Juxtaposition Twin. See page 1 24. 
 
 247 
 
K. (i) Chemical symbol for potassium (Latin, kallum), q.v.; 
 (2) absolute temperature scale: see page 205. 
 
 Kr. Chemical symbol for krypton: see page 84. 
 
 K. C. Armor. Krupp cemented armor: see page 9. 
 
 Kalamein, Kalameined. See page 373. 
 
 Kamacite. See page 291. 
 
 Kaolin. See page 396. 
 
 Kapfl Process. See page 62. 
 
 Kathode. See page 89. 
 
 Kation. See page 89. 
 
 Keen Impact Ball Tester. See page 478. 
 
 Keep's Test. (i) For cast iron: see page 483; (2) hardness test: 
 see page 480. 
 
 Keeper. See page 38. 
 
 Keller Furnace. See page 160. 
 
 Keller-Leleux Process. See page 160. 
 
 Keller Test See page 484. 
 
 Kellogg Process. See page 492. 
 
 Kennedy -Morrison Process. See page 233. 
 
 Kentledge. Pig iron shipped on a vessel as ballast. 
 
 Kern Process. See page 113. 
 
 Kernel. See page 126. 
 
 Kettle. See page 431. 
 
 Kick In. See page 406. 
 
 Kidney. See page 17. 
 
 Kidney Ore. See page 244. 
 
 Kieselguhr (German). See page 396. 
 
 Kill. (i) To hold steel in a ladle, furnace, or crucible until no more 
 gas is evolved and it is perfectly quiet; the steel is then said to be 
 dead: see page 113; (2) in the cementation process: see page 
 71; (3) of wire: see page 508. 
 Killeen Distributor. See page 32. 
 Kiln. See page 181. 
 Kilogram Calorie. See page 199. 
 Kilogram-Centigrade Heat Unit. See page 199. 
 Kimball Process. See page 73. 
 KirchhofPs Black Body. See page 207. 
 Kirkstall Bars ; Process. See page 418. 
 Kish. See Carbon. 
 Kjellin-Colby Furnace. See page 155. 
 Kjellin Furnace. See page 161. 
 Kloman Process. See page 418. 
 Knobbled Iron. Iron produced by the knobbling process : see page 
 
 79- 
 
 Knobbling Fire ; Furnace ; Process. See page 79. 
 Knoth Slag Process. See page 384. 
 Knowle Process. See page 143. 
 
 248 
 
KOGEL MILL KURZWERNHART 249 
 
 Kogel Mill. See page 418. 
 
 Komm Method. See page 501. 
 
 Konstantan. See page 209. 
 
 Konstantinoff's Iron -Phosphorus Diagram. See page 272. 
 
 Kourbatoff's Reagents. For etching: see page 287. 
 
 Kraff and Sauve Process. See page 73. 
 
 Krupp Cemented Armor. See page 9. 
 
 Krupp Furnace. See page 114. 
 
 Krupp Process. (i) For armor plate: see page 9; (2) for fluid 
 compression: see page 63; (3) for pig washing: see page 383; (4) 
 for steel: see page 318. 
 
 Kryoscopy. Name suggested by Sauveur for that branch of metal- 
 lography concerned with what happens when metallic alloys are 
 allowed to cool. 
 
 Kumer Process. See page 370. 
 
 Kurzwernhart and Bertrand Process. See page 61. 
 
L. Longitudinal, of test pieces, etc.; also length. 
 
 La. Chemical symbol for lanthanum: see page 84. 
 
 Li. Chemical symbol for lithium: see page 84. 
 
 Lu. Chemical symbol for lutecium : see page 84. 
 
 La ChaleassiSre Process. See page 63. 
 
 Labile Equilibrium; Range. See pages 269 and 327. 
 
 Laboratory. (i) A place fitted up for making chemical and phys- 
 ical tests of material; (2) the hearth of an ordinary furnace or a 
 blast furnace. 
 
 Lackawanna Deseaming Process. See page 418. 
 
 Lacquer. (i) for protection: see page 365; (2) in wire drawing: see 
 page 508. 
 
 Ladle. A large vessel or pot for holding, transporting, and pouring 
 molten material. Ladles are made of steel or iron plates with a 
 suitable refractory lining, usually (a) fire-bricks and clay for steel 
 and cast iron, and (6) cast iron for slag. Those for cast iron 
 (iron ladle) and for slag (slag ladle) are emptied by tipping them 
 (top pouring ladle). Those for steel (steel ladle) are practically 
 always provided with a hole (nozzle) in the bottom (bottom 
 pouring ladle) through which the contents are discharged. In- 
 the latter the flow is regulated by a stopper consisting of a steel 
 rod enclosed in special hollow fire-bricks (sleeve bricks); the 
 brick on the lower end which fits into the hole in the ladle is 
 called the stopper head, and is generally composed of a mixture of 
 graphite and clay; the upper end is connected with a lever on the 
 outside of the ladle. When, through faulty setting or some ob- 
 struction, the stream of steel cannot be shut off completely, it is 
 called a running stopper. The small particle of steel which usu- 
 ally solidifies on the outside of the nozzle, interfering with the 
 stream, is called a bug or fly. A bull ladle is a top-pouring ladle of 
 small capacity, usually suspended under a larger one, to facilitate 
 the filling of small molds. This is also called a shank; and the 
 verb to shank or shank off means to fill such a small ladle from a 
 larger one. A chilled heat is one which, because of the cooling of 
 the steel, and particularly of its solidifying around the stopper 
 head, cannot be poured through the nozzle (except sometimes 
 by p licking it with an iron bar) and must be poured over the top 
 of the ladle. 
 
 Ladle Additions. See Recarburization. 
 Ladle Analysis. See page 82. 
 Ladle Barrow. A wheelbarrow for carrying a ladle of molten cast 
 
 iron in a foundry. 
 Ladle Pit. See page 312. 
 Ladle Test See page 82. 
 Lag. See page 264. 
 Lagless. See page 269. 
 
 Lagrange and Hoho Process. (i) For quenching: see page 230; (2) 
 for welding: see page 503. 
 
 250 
 
LAKE IRON ORE L AUTH MILL 251 
 
 Lake Iron Ore. See page 244. 
 
 Lake Superior Charcoal Irons. See page 351. 
 
 Lamella (pi. Lamellae). See page 126. 
 
 Lamellar Eutectic. See page 269. 
 
 Lamellar Martensite. See page 276. 
 
 Lamellar Structure. See page 126. 
 
 Lamina (pi. Laminae). See page 126. 
 
 Laminated. (i) Of steel, a defect where there is a separation into 
 layers; (2) composed of separate sheets or plates in layers for 
 armature cores and structural parts. 
 
 Laminated Fracture. See page 178. 
 
 Laminated Pearlite. See page 274. 
 . Laminated Structure. See page 126. 
 
 Laminating Roller. An adjustable roller in a rolling mill for regu- 
 lating the thickness of sheets. 
 
 Lamination. See page 124. 
 
 Lancashire Process. See page 77. 
 
 Lancashire Tuyere. See page 31. 
 
 Lanceolate. Lance-shaped; tapering gradually. This term might 
 
 be discarded (I. A. T. M.). 
 : Landlocking Type, Of freezing: see page 55' 
 
 Lane Process. See page 386. 
 
 i Langlade Process. For employing blast furnace gas for heating 
 purposes; it consists in passing it through water to reduce the 
 proportion of contained steam, and also to wash it. 
 i Langley's Bolometer; Radiation Pyrometer. See page 207. 
 
 Langloan Process. Also called Addie process; for the recovery of 
 
 tar and ammonia from the gas of a blast furnace using raw coal. 
 ; Langmuir's Film Theory. See page 200. 
 i Lap; Lap Seam. See pages 405 and 426. 
 I Lap Weld. See pages 489 and 502. 
 \ Lap-welded Pipe. See page 489. 
 i Lapper. Of a sheet : see page 430. 
 i Large Bessemer Converter. See page 23. 
 i Large Calorie. See page 199. 
 { Larkin Process. See page 143. 
 
 I Larry. A car with a drop bottom, running on a track, used for 
 carrying ore, coal, etc., sometimes provided with scales for weigh- 
 ing the contents; also called lorry: see page 32. 
 i Lash-Johnson Process. See page 143. 
 
 {Latent Heat. (i) General: see page 199; (2) of fusion: see page 
 201; (3) of vaporization: see page 202. 
 
 Lateral Cleavage. See page 124. 
 
 Lateral Grain Boundary. See page 283. 
 ( Laterite. See page 245. 
 jLattens. See page 433. 
 
 Lattice Structure. See page 126. 
 
 Lauder (Geo.) Process. See page 21. 
 
 Laureau Converter. See page 24. 
 
 Laureau Process. See page 143. 
 
 Laurent's Hypothesis. See page 70. 
 'Lauth Mill. See page 414. 
 
252 LAUTH PROCESS LIGHT ALLOY 
 
 Lauth Process. See page 64. 
 
 Lavol Furnace. See page 161. 
 
 Law's Method. For sulphur prints : see page 288. 
 
 Lawrencite. See page 292. 
 
 Le Blanc's Theory. Of passivity: -see page 364. 
 
 Le Chatelier Pyrometers. (i) Calorimetric : see page 207; (2) 
 couple: see page 209; (3) optical: see page 207; (4) recording : see 
 page 210; (5) thermoelectric: see page 208. 
 
 Le Chatelier's Reagents. See page 187. 
 
 Le Chatelier's Theory. (i) Of equilibrium: see page 328; (2) of 
 hardening: see page 280. 
 
 Le Fer Process. See page 166. 
 
 Lead. Pb; at. wt.,_207; melt, pt., 325 to 335 C. (617 to 649 F.); 
 sp. gr., 11.3. It is rarely found in the uncombined state; usually 
 in combination with sulphur or oxygen. The pure metal is bluish 
 white in appearance, and very soft and malleable; it is possessed 
 of only a moderate degree of strength. It is not found alloyed 
 with iron except as an impurity. In the molten condition it is 
 sometimes used in tempering; in combination with tin it is 
 employed for coating thin sheets which are then called terne 
 plates (see page 432). 
 
 Lead Burning. Soldering: see page 505. 
 
 Lead Hardening ; Quenching; Tempering. See pages 227 and 228. 
 
 Leading Spindle. See page 407. 
 
 Leaker. See page 492. 
 
 Lean. (i) Of ores : low grade; having a small percentage of metallic 
 contents; (2) of clays, etc.: lacking in binding properties or plas- 
 ticity; (3) of cinder: see page 35; (4) of coal: See Coal. 
 
 Least Principal Stress. See page 332. 
 
 Leckie Process. See page 143. 
 
 Ledeburite. See page 277. 
 
 Lees Coating ; Liquor. See page 508. 
 
 Lencauchez Process. See page 318. 
 
 Lenticular. Having the shape of a lens or lentil. 
 
 Leplay's Hypothesis. See page 70. 
 
 Lesser Calorie. See page 199. 
 
 Let Down. (i) To dilute, e.g., pig iron is let down with scrap to 
 reduce the percentage of carbon, etc.; (2) of carbon, to reduce or 
 remove; (3) of hardness, to remove to a certain exent by tem- 
 pering. 
 
 Letting-down Tints. Temper colors: see page 230. 
 
 Leucopyrite. See page 244. 
 
 Levaz Converter . See page 24. 
 
 Leveling. Of blast: see page 34. 
 
 Lever Shears. See Shears. 
 
 Liberty, Degree of. See page 327. 
 
 Lie Back. See page 36. 
 
 Liebermeister Process. See page 143. 
 
 Lift See page 33. 
 
 Lift Hammer. See Hammer. 
 
 Lifting Table. See page 408. ., 
 
 Light Alloy ; Metal. See Alloy. 
 
LIGNITE LINING 253 
 
 Lignite. See Coal. 
 
 Lilienberg Process. See page 63. 
 
 Lime. (i) Rarely the chemical element, calcium; (2) limestone, i.e, 
 the raw stone; (3) burnt lime.or the oxide; see page 396. 
 
 Lime Annealing. See page 232. 
 
 Lime Bath. See page 507. 
 
 Lime Cooling. See page 232. 
 
 Lime Dinas Brick. See page 395. 
 
 Lime Set. See page 35. 
 
 Limestone. (i) As a flux: see page 175; (2) as a refractory: see 
 page 39 6 - 
 
 Liminate Roller (Eng.). Same as laminating roller, q.v. 
 
 Liming. See pages 342 and 507. 
 
 Limit Gage. See page 186. 
 
 Limit of Linear Elasticity ; Proportionality. See page 334. 
 
 Limiting Concentration. See page 108. 
 
 Limiting Stress. See page 333. 
 
 Limonite. See page 244. 
 
 Lindenthal Process. See page 318. 
 
 Lines. Of a blast furnace: see page 27. 
 
 Line Down ; Line Up ; Liner. See page 414. 
 
 Lining. (i) Of a blast furnace: see page 27; (2) in puddling: see 
 page 376; (3) of rolls (verb) : see page 414. 
 
 Lining. The inside portion or skin; in a furnace, etc., that portion 
 which comes in contact with the charge and protects the walls 
 proper from fusion or corrosion. They must be of such a nature 
 as not to be softened appreciably at the temperature employed, 
 and, as a rule, should be only slightly affected (if at all) by the 
 components of the charge. They may be of metal (e.g., cast iron 
 for ladles which hold blast furnace slag), but generally consist 
 of earthy material applied in a crushed condition, or as rocks or 
 bricks. Acid linings may be of sand, silicious rocks, or silica 
 bricks; basic linings, of crushed burnt dolomite, or magnesite 
 (more rarely of lime), magnesite bricks or basic slag, etc.; neutral 
 linings of coke or chrome ore either crushed or in bricks. Linings 
 for most types of furnace are applied in a crushed condition, 
 sometimes moistened with a little water, or mixed with a little 
 pitch or tar, and sintered or set in place by the high temperature 
 to which they are exposed. Basic bottoms, slag bottoms, cinder 
 bottoms, or oxide bottoms for heating furnaces consist of scale, 
 cinder, or ore. Owing to the scale which melts and runs off the 
 pieces of iron or steel being heated, the bottom in time becomes 
 excessively thick, and is occasionally reduced to the proper pro- 
 portion and also leveled off by raising the temperature until a 
 sufficient amount has been melted off. If the bottom has a slope, 
 so that nearly all the scale runs out of the furnace as fast as it 
 forms, it is called a dry bottom; if allowed to collect and tapped 
 out only at intervals , a wet bottom, or fluid bottom. Acid bottoms 
 or sand bottoms are composed of various grades of sand which 
 usually contain enough impurities to cause them to set. Their 
 thickness is gradually increased by the melted scale from the 
 metal, in spite of the fact that this causes a certain amount of cor- 
 
254 LINKAGE FORMULA LONG TUYERE CONVERTER 
 
 rosipn. They are leveled off by throwing in a little coke and b} 
 raising the temperature, the joint action serving to melt and flu^ 
 away the upper layers. A coke bottom is made of crushed cok4 
 rammed into place, usually mixed with a little cinder or tar t<| 
 cause it to set when heated; in the case of soaking pits, crusheq 
 coke or coke dust is loosely thrown on the bottom of the pits. 
 
 Linkage Formula. See page 86. 
 
 Lintel Plate. See page 27. 
 
 Lip. The depression in the edge of a ladle through which the con- 
 tents are poured. 
 
 Liquation. See pages 55 and 68. 
 
 Liquid Blacking. See page 298. 
 
 Liquid Cements. See pages 67 and 69. 
 
 Liquid Compression. See page 63. 
 
 Liquid Contraction. See page 53. 
 
 Liquid Crystal. See page 123. 
 
 Liquid Furnace. Containing a molten bath, such as a fused salt or 
 metal, in _ which the object is submerged; used particularly in 
 heat treating work. 
 
 Liquid Solution. See page 270. 
 
 Liquid Squeezed. See page 64. 
 
 Liquid State. See page 81. 
 
 Liquidoid. See page 270. 
 
 Liquidus ; Liquidus Curve. See page 268. 
 
 Liquor -Bright Process. See page 508. 
 
 List; List Pot. See page 432. 
 
 Lithosiderite. See page 291. 
 
 Littoral Region. In the freezing of alloys : see page 54. 
 
 Live Load. See page 468. 
 
 Live Pass. See page 405. 
 
 Live Roller. See page 407. 
 
 Lively. Of molten steel in the ladle or molds: bubbling or rising 
 to a certain extent, due to the evolution of gas. 
 
 Load. See page 332. 
 
 Loading Test. See page 477. 
 
 Loam. See pages 296 and 396. 
 
 Loam Brick; Cake. A slab or cake of loam used in molding. 
 
 Loam Molding. See page 300. 
 
 Local Elastic Limit. See page 282. 
 
 Local Elongation. See page 474. 
 
 Localized Corrosion; Selective Corrosion. See page 106. 
 
 Lock Joint. A joint or seam in tubes,' sheets, cans, etc., produced 
 by folding the edges over together. 
 
 Locus (pi. Loci). See Curve. 
 
 Lodestone. See page 244. 
 
 Logometer. See page 208. 
 
 Lohmann Bath; Process; Lohmannizing. See page 373. 
 
 Lollingite. See page 244. 
 
 Lombardy Process. See page 78. 
 
 Long-tailed Monkey. See Monkey. 
 
 Long Ton. See Ton. 
 
 Long Tuyere Converter. See page 24. 
 
LONGITUDINAL ROLLING LUTE 255 
 
 Longitudinal Rolling. See page 414. 
 
 Longitudinal Seam. See Seam. 
 
 Longitudinal Test Piece. See page 469. 
 
 Look over a Heat. In crucible practice : see page 114. 
 
 Loop. See page 135. 
 
 Looping ; Looping Mill. See page 416. 
 
 Lorry. See Larry. 
 
 Lost Head. See page 299. 
 
 Lost Pass. See page 405. 
 
 Lost-wax Process. See page 301. 
 
 Loup. See page 135. 
 
 Low. Of springs which upon testing are more or less flattened (not 
 good). 
 
 Low Carbon Steel. See page 455. 
 
 Low Gage. See page 186. 
 
 Low Grade. Sometimes used for low carbon. 
 
 Low Grade Fireclays. See page 396. 
 
 Low Heat Treatment. In the Taylor-White process: see page 446. 
 
 Low Phosphorus Pig. See pages 344 and 346. 
 
 Low Process. See page 118. 
 
 Low Steel (rare). Soft or low-carbon steel. 
 
 Low Temper Steel. See Temper. 
 
 Lower Freezing Point. See page 267. 
 
 Lowering Temperature. See page 447. 
 
 Lucas Process. See page 143. 
 
 Liiders Lines. See page 283. 
 
 Ludlum Furnace. See page 162. 
 
 Ludwik's Method. For determining hardness: see page 478. 
 
 Lug. A knob or projection on a smooth surface used for picking it 
 up, etc. 
 
 Lugging (Eng.). Of material which tears or does not cut crisply. 
 
 Lump. (i) The ball from a direct process : see page 135; (2) a prod- 
 uct in puddling (obs.): see page 378; (3) a piece of ganister, etc., 
 forming part of a refractory lining: see page 395. 
 
 Lumpy. Of rails, or bars, short kinked or wavy. 
 
 Lurmann's Closed Front Arrangement. See page 32. 
 
 Lunnann Front. See page 32. 
 
 Luster ; Lustre. A term used in describing the character of the 
 reflections obtained from the fractured surfaces of minerals and 
 rocks (I.A.T.M.). 
 
 Lute. A mixture of fireclay, etc., used to seal up cracks when heat 
 is to be applied, e.g., between a crucible and its cover to make an 
 air-tight fit; also the operation. 
 
M 
 
 Mg. Chemical symbol for magnesium, q.v. 
 
 Mn. Chemical symbol for manganese, q.v. 
 
 Mo. Chemical symbol for molybdenum, q.v, 
 
 M. C. B. Master Car Builders (association). 
 
 M. P. Melting point. 
 
 McCance's Interstrain Theory. Of hardening: see page 281. 
 
 McClenahan Process. See Flux. 
 
 McCloud Process.- See page 419. 
 
 McConnell (Niven) Process. See page 318. 
 
 McDonald Distributor. See page 32. 
 
 McHaffie Process. See page 258. 
 
 McKenna's Formula. For quality : see page 340. 
 
 McKenna Process. See page 419. 
 
 Machine Cast Pig. See page 342. 
 
 Machine Molding. See page 301. 
 
 Machine Puddled. Wrought iron made in a mechanical puddler : 
 see page 379. 
 
 Machining. See Cold Working. 
 
 Macintosh Process. See page 73. 
 
 Macle. See page 124. 
 
 Macro-Metallography. See page 263. 
 
 Macroscopic. Or megascopic : a term used in contradistinction to 
 microscopic, to imply that the character in question is visible to 
 the naked eye (I. A. T. M.). 
 
 Macroscopic Analysis. See page 284. 
 
 Macroscopic Etching. See page 286. 
 
 Macroscopic Metallography. See page 263. 
 
 Macroscopic Strain. See page 280. 
 
 Macroscopic Structure. Or macrostructure : see page 289. 
 
 Macroscopically Amorphous. See page 127. 
 
 Macrostructure. See page 289. 
 
 Macrostructure Etching. See page 286. 
 
 Magdolite. See page 397. 
 
 Magma. See page 125. 
 
 Magnesia. (i) As a flux: see page 175; (2) as a refractory; see page 
 396. 
 
 Magnesia Brick. See page 397. 
 
 Magnesian Limestone. See page 397. 
 
 Magnesite ; Magnesite Brick. See page 396. 
 
 Magnesium. Mg.; at. wt., 24; melt, pt., 632.6 C. (1141.9 F.); 
 sp. gr., 1.7. It is a silvery white metal with a very strong affinity 
 for oxygen, for which reason it is employed as a deoxidizer for 
 copper; in the case of steel, however, it has not proved to be as 
 satisfactory as aluminum, as the reaction is very violent. 
 Magnet Steel. See page 450. 
 Magnetic Alloy. See Alloy. 
 Magnetic Analysis. See page 284. 
 
MAGNETIC CONCENTRATIONMALLEABLE 257 
 
 Magnetic Concentration. See Ore. 
 
 Magnetic Hardness. See page 450. 
 
 Magnetic Iron Ore. See page 244. 
 
 Magnetic Method. For determining critical points: see page 266. 
 
 Magnetic Oxide Theory. Of puddling: see page 378. 
 
 Magnetic Pyrites. See page 245. 
 
 Magnetic Separation. See Ore. 
 
 Magnetic Steel. See page 450. 
 
 Magnetic Transformation^ See page 264. 
 
 Magnetite. See page 244. 
 
 Magnite. See page 399. 
 
 Magnobrent. See page 399. 
 
 Main Spindle. See page 407. 
 
 Major Calorie. See page 199. 
 
 Major Shrinkage. See page 54. 
 
 Make Bottom. See page 313. 
 
 Make a Cast ; Heat. Melting iron in a cupola for foundry work. 
 
 Malleability. See page 331. 
 
 Malleable. (i) Malleable castings (#.*>.); (2) pig iron suitable for 
 making into malleable castings: see page 346. 
 
 Malleable Bessemer. See page 346. 
 
 Malleable Cast Iron. See below. 
 
 Malleable Castings. Also called malleable iron, malleable cast 
 iron, malleable, or malleablized cast iron; more rarely temper 
 (tempered) castings or run steel. They are castings in which the 
 combined carbon of white cast iron has been converted into an 
 amorphous, uncombined condition by special heat treatment 
 without fusion, leaving the iron soft and to a certain extent mal- 
 leable. The process was discovered by Reaumur, and hence the 
 product was at one time known as Reaumur iron. The carbon 
 exists in small spots or patches which do not break up the con- 
 tinuity of the iron matrix nearly so much as the large thin 
 plates of graphite in ordinary gray cast iron which serve as cleav- 
 age planes. This form of carbon is termed temper carbon or 
 temper graphite, more rarely annealing carbon. 
 
 The process consists essentially in heating white cast iron cast- 
 ings (hard castings), in which practically all the carbon is in 
 the combined condition, to a temperature above about 750 C. 
 (1380 F.), but below its melting point, say under 1100 C. (2010 
 F.;, when the conversion of the carbon to the amorphous uncom- 
 bined condition takes place, apparently due principally to the 
 silicon (assisted by the heat) of which a certain percentage must 
 be present. If the castings are heated too hot, and in conse- 
 quence become softened and deformed, they are said to fall. A 
 mixture of pig iron to give the desired composition is melted in a 
 cupola, an air furnace (reverberatory), x>r a furnace similar to 
 that used in the open hearth process, and is then poured into the 
 molds. When an open hearth furnace is used, and it is first put 
 into service, the initial heat, called a pill heat, is usually cast into 
 pigs for remelting, as it is not certain whether the metal will be 
 satisfactory. When the charge consists chiefly of runners and 
 defective castings, it is termed a sprue heat. 
 17 
 
258 MALLEABLE COKE IRON MANGANESE 
 
 The castings are usually less than an inch in thickness, so the 
 cooling will be sufficiently rapid to prevent the formation of 
 graphite. The original shrinkage is about double that of gray 
 castings, but about half of this is recovered upon annealing. 
 After cleaning, they are packed in some material, such as ore or 
 clay, contained in a box called a sagger or annealing pot, to pro- 
 tect them from the air and so prevent excessive formation of 
 scale which would produce what are termed scaled castings. 
 Reaumur's process ("of softening cast. iron"), which is also that 
 used principally abroad (hence, European or old European proc- 
 ess), employs new iron ore which causes, in the case of thin 
 castings, most of the carbon to be oxidized and removed (decar- 
 burizing process), so that, on breaking, the fracture is nearly 
 white throughout (white-heart malleable or casting). In this 
 country (American process) the packing material is generally 
 made up of two or three parts of old ore (burnt ore or spent ore) , 
 which has only a slight oxidizing effect, and one part of new 
 ore. This restricts the oxidation of the carbon to that in the 
 outer layers, so that the carbon in the interior is simply changed 
 to the amorphous condition, and the fracture shows a white 
 outside skin with a black interior, from which comes the name 
 black-heart malleable or casting. 
 
 The heating operation (annealing) requires a number of days 
 and is performed in an annealing furnace or oven, the boxes being 
 arranged so the flame may play around them as completely as 
 possible; the flame usually enters at the top of the furnace and 
 leaves at the bottom along the side, and then passes through 
 flues underneath. 
 
 In the Terreault and Hilzinger process the cast iron is melted 
 in crucibles with about 0.25% of sodium chloride and the castings 
 are poured in the ordinary way. They are then placed in anneal- 
 ing boxes and packed in scale which has first been soaked in a 7.5 
 % solution of ammonia (/. /. & S. I., 1911, 1, 605). The McHaf- 
 fie process does not appear to differ essentially from ordinary 
 practice. 
 
 Malleable Coke Iron. See page 340. 
 
 Malleable Iron. (i) Wrought iron; (2) malleable cast iron: see 
 above; (3) pig iron suitable for making into malleable castings: 
 see page 346. 
 
 Malleable Pig Iron. See page 344. 
 
 Malleable Wrought Iron. Wrought iron, q.v. 
 
 Malleablized Cast Iron. See page 257. 
 
 Manganese. Mn; at. wt., 55; melt, pt., 1207 C. (2200 F.);sp. 
 gr., 7.42. It is found in combination with oxygen, and usually 
 in conjunction with iron. The pure metal has a grayish white 
 color, with a slight tinge of red, and is hard and brittle. It is 
 obtained as an alloy with iron called ferro-manganese or spiegel, 
 rarely manganese (see page 352), and very recently with silicon, 
 called silico -spiegel (see page 354). It has a stronger affinity for 
 oxygen and sulphur than has iron. Next to carbon it is the most 
 important constituent of steel. In ordinary amounts its most 
 valuable property is in removing oxygen existing in the steel 
 
MANGANESE ADDITIONS MARQUETTE 259 
 
 either as a gas or in direct combination as oxide (see page 393). 
 As a desulphurizing agent, see page 386. In ordinary steel the 
 manganese varies from about 0.30 to 1.00%; below 0.30 the 
 removal of oxygen does not seem to be sufficiently thorough (ex- 
 cept with steel made in a crucible or in an electric furnace, etc.), 
 while above 1.50%, and up to about 6 or 7%, the hardness and 
 the brittleness under shock increase so rapidly that the material is 
 not of commercial value. Above the limit mentioned, and up to 
 about 15%, a curious reversal takes place, the metal remaining 
 very hard, but becoming tough upon suitable treatment; this 
 metal is called manganese steel (see page 451). Above about 16 
 or 17% the metal becomes more brittle again. Manganese in 
 increasing amounts raises the saturation point of iron for carbon. 
 For influence on corrosion : see page 366. 
 
 Manganese Additions. See Recarburization. 
 
 Manganese Carbide. See page 279. 
 
 Manganese Carbon Iron ; Steel. A term rarely employed for ordi- 
 nary steel or cast iron containing not over about 1.50% or 2.00% 
 of manganese, to distinguish it from manganese steel which has 
 over about 10 % of manganese. 
 
 Manganese Ore. See page 245. 
 
 Manganese Silicate. See page 279. 
 
 Manganese Spot. See Hard Spot. 
 
 Manganese Steel. See page 451. 
 
 Manganese Steel Lines. See page 127. 
 
 Manganese Sulphide. See pages 279 and 289. 
 
 Manganic. Manganese in chemical compounds having the higher 
 valence III. 
 
 Manganiferous. Containing or carrying manganese. 
 
 Manganiferous Cementite. See page 279. 
 
 Manganiferous Iron Ore. See page 245. 
 
 Manganin. See page 209. 
 
 Mangano-Ferrite. See page 272. 
 
 Mangano-Magnesian Magnetite. See page 244. 
 
 Manganous. Manganese in chemical compounds having the lower 
 valence II. 
 
 Mangle (Eng.). A set of straightening rolls for plates, etc. 
 
 Manipulator. See page 411. 
 
 Manne smarm' s Equilibrium Diagram. See page 272. 
 
 Mannesmann Process. See page 490. 
 
 Mantle (Mantel) Ring. See page 27. 
 
 Manufacturing Coal. See Coal. 
 
 Many-blow Test. See page 482. 
 
 Marcasite. See page 245. 
 
 Marel Brothers Process. See page 64. 
 
 Margarite Structure. See page 125. 
 
 Mariotte's Law. See Gas. 
 
 Marking. Branding : where rolls are engraved and brand appears 
 on rolled piece in raised characters ; stamping : where characters 
 are forced into the surface. Both are called marking which also 
 includes painting, tagging or other means of identification. 
 
 Marquette d'Encrenee (Fr.). See page 135. 
 
260 MARTENS' REAGENTS MECHANICAL HARDNESS 
 
 Martens and Heyn's Reagent For etching: see page 288. 
 
 Martens' Reagents. For etching: see page 287. 
 
 Martens Test. For hardness : see page 480. 
 ^ Martensite. See pages 275 and 276. 
 
 Martensite Carbon. See page 276. 
 
 Martensite Steel.' Steel containing gamma iron. 
 
 Martensitic Special Steels. See page 445. 
 
 Martensitization. See page 276. 
 
 Martensitizing Methods of Hardening. See page 279. 
 
 Martien Process. See page 386. 
 
 Martin and Beavis Mill. See page 420. 
 
 Martin Furnace. See page 310. 
 
 Martin Process. See page 310. 
 
 Martin-Siemens Process. See page 310. 
 
 Martin-Siemens Steel. Open hearth steel. 
 
 Marti te. See page 244. 
 
 Mass Effect. On the physical condition of material: see page 219. 
 
 Massenez Process. (i) For steel: seepage 22; (2) for desulphur- 
 izing: see page 386. 
 
 Massive. Amorphous; not crystalline. 
 
 Massive Cementite. See page 273. 
 
 Massive Ferrite. See page 272. 
 
 Massive Magnesite. See page 397. 
 
 Massive Structure. See page 125. 
 
 Massut (Russian). The residue from the distillation of crude 
 petroleum at a temperature of about 300 C. (572 F.); it has a 
 specific gravity of about 0.90 to 0.91, and burns in an open vessel 
 at about 100 to 130 C. (212 to 266 F.); it has a calorific power 
 of about 10,000 calories, and is composed of about 87 % of carbon, 
 12 % of hydrogen, and i % of oxygen. 
 
 Matcher ; Matching. See page 430. 
 
 Mathias Deseaming Process. See page 418. 
 
 Matrix. (i) The die or mold used to give the desired form to an 
 object; (2) in metallography, the ground mass or principal sub- 
 stance in which a constituent is embedded. 
 
 Matter. (i) Definition: see page 81; (2) state of: see page 81. 
 
 Matthiessen Process. See page 143. 
 
 Matweieff's Reagent. For etching: see page 287. 
 
 Maul. A large wooden hammer used for flattening plates while 
 hot; a beetle. 
 
 Maximum Fiber Stress. See page 337. 
 
 Maximum Load; Stress. See page 335. 
 
 Maximum Temperature. And grain size; see page 213. 
 
 Meager Coal. See Coal. 
 
 Mean. Average or normal. 
 
 Mean Calorie. See page 199. 
 
 Mean Stress. See page 333. 
 
 Mechanical Amorphizing. See page 282. 
 
 Mechanical Brittleness. See Brittleness. 
 
 Mechanical Equivalent of Heat. See page 204. 
 
 Mechanical Hardness. See page 331. 
 
MECHANICAL" IMPURITY MERCADER AXLE 261 
 
 Mechanical Impurity. See Impurity. 
 
 Mechanical Methods of Etching. See page 286. 
 
 Mechanical Mixture. See page 83. 
 
 Mechanical Process. Working, as rolling or forging, as distin- 
 guished from some chemical or metallurgical process. 
 
 Mechanical Puddler; Puddling Furnaces; Rabble. See page 379. 
 
 Mechanical Refining. Improving the quality of steel or wrought 
 iron by reducing the size of the grain by working the metal 
 while cooling until the temperature has about reached the critical 
 point; sometimes called hammer refining: See page 216. 
 
 Mechanical Stirrer. See page 379. 
 
 Mechanical Thermometer. See page 205. 
 
 Mechanical Tinning Pot. See page 432. 
 
 Mechanical Treatment. For producing solid castings: see page 
 
 59- 
 
 Mechanical Twin. See page 124. 
 Mechanical Working. Usually referred to in connection with its 
 
 effect on the physical properties as distinguished from that pro- 
 duced by heat treatment alone. 
 Mechanically Combined Water. See Water. 
 Mechanico-chemical Methods of Etching. See page 288. 
 Medicine Room. See page 115. 
 Medium Carbon Steel. See page 455. 
 Medium Grade Fireclays. See page 396. 
 Medium Steel. See page 455. 
 Medium Temper Steel. See Temper. 
 Megascopic. Macroscopic, q.v. 
 Meiler. See Charcoal. 
 Melanterite. See page 245. 
 Meldometer, Joly. See page 207. 
 Mellen Rod-casting Process. See page 65. 
 Melloni Thermopile. See page 207. 
 Melt. (i) To fuse; (2) a heat or charge of steel. 
 Melt High; Low. See page 314. 
 Melter. The man in charge of a crucible furnace, cupola, or open 
 
 hearth furnace. 
 Melting. See page 201. 
 
 Melting Down Refinery ; Melting Finery. See page 383. 
 Melting Furnace. Any furnace in which metals can be melted, 
 
 more especially cast iron. 
 Melting Heat. See page 71. 
 
 Melting Hole. Of a crucible furnace: see page 114. 
 Melting House (Eng.). A department in a. steel works for making 
 
 crucible steel. 
 
 Melting Point. See page 201. 
 Melting Point Curve. See Curve. 
 Melting Point Pyrometry. See page 209. 
 Melting Refinery. See page 383. 
 Menacconite. See page 245. 
 Mendelejeff's Periodic Law. See page 85. 
 Mercader Hollow -pressed Axle. An axle produced by a process 
 
 somewhat similar to the Erhardt process. A heated, round 
 
262 MERCHANT METALLOGRAPHIC EXAMINATION 
 
 blank, after removal of the scale in a set of cross rolls, is placed in 
 a die having the shape of the finished axle, and a punch is forced 
 (hydraulically) into each end, to a depth sufficient to displace 
 enough metal to fill out the die and also upset the metal at the end 
 for the collars. A few axles were made and placed in service, 
 but the process never really got beyond the experimental stage, 
 due principally to difficulty in keeping the punches concentric 
 with the axis of the axle. 
 
 Merchant. In general, an adjective used to denote material which 
 is finished or for sale, also the appliances for its production. 
 
 Merchant Bar. See page 3 78. 
 
 Merchant Furnace. See page 39. 
 
 Merchant Mill. See page 409. 
 
 Mercurial (Mercury) Thermometer. See page 205. 
 
 Merging. See page 120. 
 
 Merging of Critical Points. See page 264. 
 
 Merit Number. See page 340. 
 
 Meritens (A. de )Process. See page 369. 
 
 Memman's Formulae. For tensile strength: see page 338. 
 
 Merrit Plate. See page 135. 
 
 Mesh Structure. See page 126. 
 
 Mesosiderite. See page 291. 
 
 Mesure and Nouel's Pyroscope. See page 208. 
 
 Metacryst. See page 122. 
 
 Meta -Element. See page 81. 
 
 Metal. (i) Any metallic element in its reduced form: see page 83; 
 (2) pig iron or steel, more particularly the former, when the 
 meaning is obvious; (3) the product of a refinery: see page 383. 
 
 Metal Notch. See page 32. 
 
 Metal Sponge. See Alloy. 
 
 Metal Spraying. See page 373. 
 
 Metal Stove. See page 34. 
 
 Metallic. Having the properties of a metal, more especially the 
 physical ones, such as luster, opacity, ductility, etc. 
 
 Metallic Alloy. See Alloy. 
 
 Metallic Cementation. See pages 66 and 370. 
 
 Metallic Coating. See page 370. 
 
 Metallic Fog. See page 128. 
 
 Metallic Luster. See page 83. 
 
 Metallic Nickel. See page 353. 
 
 Metallic Solid Solutions. See page 270. 
 
 Metallic Thermometer. See page 205. 
 
 Metallicity; Metalleity. Condition or quality of being metallic. 
 
 Metallifacture (obs.). Metallurgy. 
 
 Metalliferous. Containing a metal, as an ore or deposit. 
 
 Metallify. Smelt or reduce into a metal. 
 
 Metalline. Metallic. 
 
 Metallize. (i) To coat with a metal; (2) to convert or reduce to 
 the metallic state, as an ore; (3) to impregnate with metallic or 
 mineral substances, as wood. 
 
 Metallographic Examination. See page 284. 
 

 METALLOGRAPHY 263 
 
 Metallographic Method. For determining critical points: see 
 
 page 265. 
 
 Metallography. That branch of metallurgy which treats of the 
 constitution and the structure of metals and alloys, and their 
 relation to the physical properties. This definition covers the 
 very broad field which it is now recognized that metallography 
 occupies, and any method of research may be employed. When 
 it was a comparatively new science, however, it was familiarly 
 supposed to be concerned principally with the visual exami- 
 nation of the structure of metals and hence was divided into 
 microscopic or micrometallography where the microscope was 
 employed to secure high magnifications, and megascopic, 
 macroscopic or macrometallography where the naked eye or very 
 low magnifications were used. 
 
 The following are briefly the principal events, in their chrono- 
 logical order, which are responsible for our present knowledge of 
 the subject : 
 
 1864. Sorby (British Assoc.) published his work on the 
 microscopic examination of iron and steel, which he had com- 
 menced the preceding year. This did not bear any fruit until 
 after 1887, in which year he read, by request, a paper on the sub- 
 ject before the Iron and Steel Institute. 
 
 1869. Gore (Proc. Roy. Soc.) published the results of his 
 experiments on the dilatation of steel at high temperatures. The 
 method employed was a wire stretched horizontally which, by 
 means of a series of levers, indicated the amount of expansion or 
 contraction during heating" or cooling. At a dark red, he found 
 on cooling a greater dilatation than immediately above or below' 
 that temperature. He called this phenomenon recalescence, 
 because of the momentary brightening which accompanied it. He 
 did not, however, observe the reverse effect during heating. 
 
 1873. Barrett (Phil. Mag.) carefully checked the work of Gore 
 and found the reverse effect occurred during heating at nearly the 
 same temperature as during cooling. He noted that this point 
 was slight in the case of soft steels. 
 
 1880. Hogg stated that quenched steel showed less carbon 
 by the Eggertz color method than the same steel annealed. About 
 this time iron carbide, Fe 3 C, was isolated from annealed steel by 
 Weyl, Abel and Mueller. 
 
 1885. Osmond and Werth (Ann. d. Mines') published their 
 paper on the cellular theory of steel. 
 
 In the years immediately following Osmond (Mem. Artil. et 
 Mar.} gave the results of his experiments on the transformation of 
 iron and carbon, employing cooling curves obtained by means of a 
 Le Chatelier electrothermic pyrometer. 
 
 1886. Pionchon made experiments on the specific heats at 
 different temperatures certain seeming anomalies pointing to 
 allotropic transformations. 
 
 1890. H. Le Chatelier published variations in electrical resist- 
 ance at different temperatures, confirming the resultapobtained 
 by other methods. 
 
 1895. Osmond published (Butt. Soc. d'Enc.) his classical 
 
264 METALLOGRAPHY 
 
 monograph on the "General Method for the Microscopical Exami- 
 nation of Carbon Steels." 
 
 1899. Roberts- Austen plotted the first iron-carbon diagram, 
 corrected and amplified by Roozeboom, the following year, on the 
 basis of the phase rule. 
 
 Other investigators to whom particular tribute must be paid 
 are Howe, Sauveur, Stead and Arnold. 
 
 Iron or steel, when solid, consists of grains or crystals the size 
 of which depends upon the heat treatment and the mechanical 
 treatment they have received. Ordinarily iron or steel is not 
 homogeneous, but is composed of a variety of substances or 
 constituents (in the same way that rocks are made up of different 
 minerals) depending upon (a) the proximate chemical composi- 
 tion, and (6) the heat treatment. "The microscopic constitu- 
 ents of steels are divided into those that are chemically homogene- 
 ous (metaral) and those that are chemically heterogeneous (ag- 
 gregate) "(I. A. T. M.). 
 
 Allotropic Modifications. Metallography is based on Os- 
 mond's demonstration (Osmond's theory, allotropic theory) that 
 iron is susceptible of three allotropic varieties or modifications 
 known respectively as alpha (a) iron, beta (/3) iron, and gamma 
 (7) iron, each being normal for a given range of temperature and 
 conditions. 
 
 Transformations and Critical Points. It has been known for 
 some time that the rate of cooling or heating does not always 
 proceed uniformly, but that at certain temperatures (which may 
 vary with different compositions) retardations occur, and these 
 are termed arrestation points, critical points (critical tempera- 
 tures), transformation points, or transition points. These are 
 caused by physical changes whereby heat is liberated on cooling 
 and absorbed on heating. There are three principal critical 
 points for iron designated A\, A 2 , and At, A\ being at the lowest 
 temperature. On account of molecular inertia or lag (Howe), 
 the changes occur at lower temperatures on cooling than on heat- 
 ing unless the rates are infinitely slow. The transformation at 
 A 2 is also referred to as the magnetic transformation. To indi- 
 cate such conditions Howe has called these theoretical points 
 Ae, etc., (e standing for equilibrium). In certain grades of iron 
 two or even all three points may occur at the same temperature 
 (merging of the critical points), and to show this they are written, 
 e.g.) Ar3_2, Ar 3-2-1. For hypereutectoid steel Sauveur suggests 
 for the upper critical point "the symbol Acm (Arcm on cooling 
 and Accm on heating), cm standing for cementite. At least one 
 writer, however, has designated this point on cooling by the nota- 
 tion Armc, me standing for massive cementite" (Sauveur, Metal- 
 lography, 1 66). A point found by Roberts- Austen between 550 
 and 600 C. for iron and soft steel he called Ar . " Roberts-Aus- 
 ten detected another evolution of heat in pure iron between 450 
 and 500 C., the existence of which he ascribed to the presence of 
 hydrogen (hydrogen point) resulting in a separation of hydroxide 
 of iron taking place at this critical point. Finally the same 
 observer described one more slight evolution of heat in pure iron 
 
METALLOGRAPHY 265 
 
 at about 270 C. which he tentatively ascribed to the formation of 
 an iron iron hydroxide eutectic (ibid., 167). Brinell used the 
 letter W for the upper point and V for the lower point of the 
 hardening or transformation. Tschernoff used the letter A to 
 indicate the temperature above which hardening could be pro- 
 duced by quenching, but below which hardening could not be pro- 
 duced. In some cases a retardation may occur not simply at or 
 near one temperature but over a more or less extended range 
 (critical range or interval, etc.). The rate at which a transforma- 
 tion occurs is known as the speed or velocity of transformation. 
 In some cases while cooling through Ari, there is such a liberation 
 of heat that the temperature may be raised slightly and in the 
 dark a sudden glowing can be observed; this phenomenon is 
 termed recalescence (the piece is said to recalesce) or rarely 
 calescence or Gore's phenomenon, and the temperature at which 
 it occurs, the recalescent point; to indicate the reverse effect on 
 heating, it is sometimes called the decalescent point, absorption 
 point or temperature, and without reference to heating or cooling 
 respectively the calescent point. At this point a softening action 
 takes place which is shown by Coffin's bend: if an iron bar, 
 heated above Ari is supported at its ends only, and then allowed 
 to cool, when' the temperature reaches Ari it will bend, although 
 this does not occur just above or just below. Alloys (and trans- 
 formations), where there is a very wide interval (temperature 
 interval, hysteresis temperature, hysteresis gap) between the 
 temperature of the critical point on heating and cooling are said 
 to be non-reversible or irreversible ; where the interval is not so 
 marked, and in contradistinction, reversible (Sauveur suggests 
 100 C. as an arbitrary limit). 
 
 Commercial iron is never pure, and the elements (including 
 iron) of which it is composed may exist (a) in chemical combina- 
 tion, forming definite chemical compounds, (b) in solution (solid 
 solution: see below), where one element or substance is dis- 
 solved in another in varying proportions, and (c) as mechanical 
 mixtures of elements or compounds. The most important ele- 
 ment to be associated with iron is carbon, which has a wider 
 effect on iron than any other, and even when special elements 
 such as nickel, chrome, etc., are introduced its influence still 
 predominates or governs those of the others. A consideration of 
 the various relations between iron and carbon is therefore neces- 
 sary, not only because they are always in evidence, but also 
 because it will serve to explain the relations of other elements. 
 
 Determination of Critical Points. These may be listed as 
 follows : 
 
 (1) Thermal or cooling and heating curve methods : Changes in 
 the ra'tes of cooling or heating. Various methods of determina- 
 tion have been devised and also for plotting the corresponding 
 values of time and temperature. 
 
 (2) Calorimetric methods: Determining the amount of heat 
 evolved at different temperatures. 
 
 (3) Metallographic methods : Examination of the structure 
 resulting by quenching from various temperatures. 
 
266 METALLOGRAPHY 
 
 (4) Thermo-electric methods: Changes in the thermo-e.m.f. 
 of the specimen and copper when at different temperatures. 
 
 (5) Magnetic method: Changes in the thermo-magnetic 
 properties. 
 
 (6) DUatadon methods: Changes in the rate of expansion or 
 contraction. 
 
 Freezing and Solidification. In approaching this subject it 
 will be simpler to study first the somewhat analogous and simpler 
 case of what happens when solutions containing different propor- 
 tions of water and common salt (NaCl), varying from o to 100% 
 of each respectively, are cooled (this is the common example 
 employed, although Howe states that, owing to certain com- 
 plications, sodium nitrate is better). If pure water is cooled its 
 temperature falls regularly until o C. is reached, when freezing 
 occurs (freezing point), the temperature remaining constant 
 until all the water has frozen, after which the fall in temperature 
 again proceeds regularly. If a solution containing a small per- 
 centage of salt, say about 2 % is cooled, freezing does not com- 
 mence until a temperature below o C. has been reached, when, 
 however, the entire solution does not freeze as before. Instead, 
 small portions of nearly pure ice are gradually formed as the tem- 
 perature is progressively reduced, the remaining solution, in 
 consequence, becoming richer and richer in salt. This gradual 
 separation of ice is known as selective, progressive or differen- 
 tial freezing. Finally at 22 C. the temperature remains 
 stationary until the remaining concentrated solution or mother 
 liquor, which now contains 23.6 % of salt has completely solidified. 
 This last freezing substance consists, not of crystals of salt dis- 
 solved in ice, but of separate intimately mixed, microscopic 
 plates of ice and salt. This mixture is termed a cryosel, cryo- 
 hydrate (Guthrie's cryohydrate), duplex constituent, or the more 
 general term, eutectic (also eutectic mixture and eutecticum) . 
 The temperature at which this occurs is termed the eutectic 
 point, and the line joining the points for a series of compositions 
 the eutectic line; the time occupied for such freezing is the 
 eutectic time. With a higher percentage of salt, say about 
 10 % cooling proceeds to a somewhat lower temperature than 
 in the preceding case before ice commences to separate out; but 
 the final freezing point and the composition of the mother liquor 
 are again 22 C. and 23.6% of salt, respectively, there 
 being of course proportionately more mother liquor. If the 
 solution contains exactly this percentage of salt, cooling proceeds 
 without any separation of ice until 22 C. is reached, when 
 the entire solution freezes out at this temperature. If more than 
 23.6% of salt is in the original solution, then salt, instead 
 of ice, separates out initially, so that at 22 C. this composi- 
 tion is reached. It will thus be seen that no matter what the 
 initial percentage of salt, the final composition at 22 C. is 
 always the same. The substance initially in excess of the com- 
 position of the eutectic (eutectic ratio) is called the excess sub- 
 stance; the other, the deficit substance. The mother liquor, 
 when on the point of forming the eutectic, is sometimes called 
 
METALLOGRAPHY 
 
 267 
 
 the eutectic solution, and eutexia is the name which has been 
 given the act of its formation. A curve for a given composition, 
 plotted to show the rate of cooling, is termed a cooling curve or 
 sometimes improperly recalescence curve (the reverse, a heating 
 curve); a curve comprising the different, critical points for a 
 series of different proportions of the same constituents is known 
 as a freezing point curve (the reverse, a melting point curve). 
 Where a cooling solution solidifies at one temperature (con- 
 gruent freezing, or isothermal freezing), this is termed the 
 freezing point; the isotherm corresponding to this freezing point 
 is known specifically as the tectotherm; if differential freezing 
 (incongruent freezing) occurs, the temperature at which freezing 
 commences, the upper freezing point; that at which freezing is 
 completed, the lower freezing point; and the range of tempera- 
 ture, the freezing range. 
 
 Freezing of Alloys. The same principles apply here as in the 
 case of the salt and water. Only binary alloys will be discussed 
 here. Those containing more than two metals are the same in 
 principle and their additional complications require special 
 
 Molten 
 
 Molten 
 Freezing Point of A 
 
 ' - _ 
 Solid A + 
 
 - 4Jquid B 
 
 Freezi 
 So 
 
 ng Point of B 
 id A and B 
 
 A-100 
 B- 
 
 Concentration 
 
 A- 
 -100 
 
 Solid Solution 
 
 A-100 
 B- 
 
 Concentration 
 
 A- 
 5-100 
 
 FIG. 32. FIG. 33. 
 
 FIG. 32. Constitutional diagram for two metals entirely insoluble 
 in each other when solid. 
 
 FIG. 33. Constitutional diagram for two metals entirely soluble 
 in each other when cold. 
 
 methods for illustration and elucidation. Figs. 32 to 37 inclusive 
 show typical diagrams for different kinds of freezing and cooling. 
 The alloy or metal, when heated to a temperature where it is 
 entirely liquid is termed the molten. A single metal, a definite 
 chemical compound, and a eutectic each freeze completely at a 
 single temperature. In the last two cases where there is an excess 
 of one of the constituents, or where the alloying metals form solid 
 solutions throughout their series, the freezing is not isothermal 
 but extends over a range of temperature. Fig. 32 shows how 
 each of two metals entirely insoluble in each other has its dis- 
 tinct freezing point which is the same as if it alone were present. 
 In figures 33 to 37 inclusive the curves show that, with the excep- 
 
268 
 
 METALLOGRAPHY 
 
 tions noted above, there are two freezing point curves; the upper, 
 or liquidus, where freezing commences, and the lower, or solidus, 
 where it is completed. In this freezing range alloys are in the 
 mushy stage sometimes spoken of. By careful cooling the alloy 
 may not freeze at a temperature below the normal temperature, 
 
 Molten 
 
 Solid Solution of A + B 
 
 Molten 
 
 Mother Meta 
 
 Mother Metal Q 
 
 Solidus 
 A+Eutectic 
 
 L Ql Solidus 
 
 A -100 
 
 Concentration 
 
 A- A -100 Concent ration 
 B - B-100 B - B-MO 
 
 FIG. 34. FIG. 35. 
 
 FIG. 34. Constitutional diagram for two metals which form solid 
 solutions at each end of the series but are partly insoluble for in- 
 termediate concentrations. 
 
 FIG. 35. Constitutional diagram for two metals which form an 
 eutectic and are entirely insoluble in each other when cold. 
 
 Molten 
 
 Solid \ A+ % 
 
 3olutioA Eutecti o 
 
 of \ 
 A+B \ 
 
 A- 100 
 B- 
 
 Solidus 
 
 Concentration 
 
 FIG. 36. 
 
 FIG. 37. 
 
 FIG. 36. Constitutional diagram for two metals partly eutecti- 
 ferous but forming solid solutions at each end of the series. 
 
 FIG. 37. Constitutional diagram of two metals which form a 
 definite chemical compound which is entirely soluble with either 
 metal when cold. 
 
 unless the condition is disturbed as by the introduction of a crys- 
 tal of -^ the alloy (inoculation); this is known as undercooling, 
 surfusion or superfusion. This is due to lag or a condition of 
 internal friction or molecular friction, also called molecular 
 
METALLOGRAPHY 269 
 
 inertia or hysteresis (see Phase Rule, page 327); where this does 
 not occur during a change of state or condition, the change is said 
 to be lagless. If cooled still further, freezing takes place spon- 
 taneously (spontaneous crystallization) when any disturbance, 
 such as jarring, occurs. These two ranges have been named by 
 Ostwald metastable range and labile range respectively. The 
 molecular inertia which prevents, or tends to prevent freezing at 
 the normal temperature, acts in accordance with what is some- 
 times termed the law of passive resistance. "Below the solu- 
 bility curve, and approximately parallel with it, lies a curve 
 representing the temperature at which each solution begins to 
 deposit spontaneously without inoculation with a crystal. To 
 this curve the name supersolubility curve has been given. The 
 intersection of two supersolubility curves is called the hyper- 
 tectic point, corresponding to eutectic point" (Desch). Sub- 
 stances separating before the eutectic forms are called 
 pro-eutectic ; if after the eutectic, post-eutectic. Depending upon 
 its structure the eutectic may be lamellar or granular. To illus- 
 trate how these diagrams are used consider what takes place in 
 cooling an alloy whose temperature and concentration are repre- 
 sented by the point R in Figs. 33 and 35. Here there is molten 
 solution, and 'no change in constitution occurs until / is reached, 
 when the alloy begins to freeze. The point M on the solidus curve 
 indicates the composition of these crystals; as the temperature 
 falls the molten becomes progressively richer in A metal, follow- 
 ing the liquidus curve, and the crystals correspondingly poorer, 
 following the solidus curve, so that when the L is reached for the 
 molten, the crystals have the concentration shown by O. The 
 intercepts JM and LO on the isothermal abscissae represent in 
 each case 100% of molten plus crystals; for JM there is 100% 
 molten and o% crystals; for LO the reverse is the case. If any 
 point P is selected within the liquidus and the solidus curve the 
 abscissae passing through it intersects them respectively at K 
 and N which indicate the concentration for each; the amount of 
 
 PN 
 
 each is found by the ratio between PK and PN, thus -^^ X 100 = 
 
 rl\. 
 
 PK 
 %K, and j^ X 100 = %N. In the case of the cooling of the 
 
 alloy which forms the solid solution the original heterogeneity of 
 the crystals is overcome by diffusion unless the cooling is unduly 
 rapid; this is not so complete with subsequent transformations in 
 solid solutions owing to the greater viscosity. With eutectics 
 there persists the simultaneous existence of eutectic and excess 
 substance; the same also in the case of eutectoids formed in solid 
 solutions. 
 
 As ordinarily understood a solution is something which is liquid 
 at or near atmospheric temperatures, whereas a molten substance 
 connotes very much higher temperatures. The question is, 
 therefore, really one of degree only, and what is true of an ordinary 
 solution is also relatively true of one which is molten. The 
 term molten or melt is accordingly used to designate this case 
 in contradistinction to solid (at lower or ordinary temperatures). 
 
270 METALLOGRAPHY 
 
 Where a molten solution solidifies with differential freezing, the 
 upper freezing point (also the curve for a series of different com- 
 positions) is termed the liquidus (also liquidus curve), the lower 
 point and curve, the solidus (also solidus curve), and the freezing 
 range, the solidification range. Where a eutectic (eutectic 
 mixture, eutectic alloy) is formed, the metal just before final 
 solidification is called the mother metal. 
 
 Metallic Solid Solution. It may at first be somewhat diffi- 
 cult to grasp the idea of changes occurring in solid material, but a 
 little thought will show that the principal difference between a 
 solid, such as a metal, and a liquid, is in the degree of mobility of 
 the particles or molecules, as no sharp division can be drawn. 
 From naphtha or alcohol, for example, as one extreme, whose par- 
 ticles are highly mobile, to a heavy oil, to molasses, to lead, to 
 highly heated steel, and finally to the same metal when cold 
 (which can still flow to a considerable extent, as in the case of 
 wire drawing) as the other extreme, the steps are relatively grad- 
 ual. We therefore properly speak of a solid solution, in which 
 the degree of viscosity is high, as similar to a liquid solution (in 
 contradistinction), such as the salt solution already discussed, in 
 which the particles have greater freedom of movement. A solid 
 solution, also termed isomorphous mixture or mixed crystals 
 (according to Professor Howe), "is a solid having the essential 
 properties which characterize liquid solutions as distinguished 
 from chemical compounds. These characteristics are twofold: 
 (i) a solution resembles a definite chemical compound in that its 
 components completely lose their identity and become integrated 
 to form a new substance; (2) solutions differ from definite chem- 
 ical compounds in that their components unite, not in definite but 
 in intermediate proportions, which vary by infinitesimal grada- 
 tions from specimen to specimen. The variations in composi- 
 tion between definite chemical compounds are per saltum, those 
 between solutions are per gradum. The properties of solutions, 
 both liquid and solid, habitually differ much less from the mean 
 of those of their components than from the properties of definite 
 chemical compounds." A solidified solution or congealed 
 solution is a "homogeneous solution after solidification, irre-v 
 spective of whether the constituents of the solution in the latter 
 siate form a mixture or a solid solution in the true sense of the 
 term" (I. A. T. M.). Metallic solid solutions, from their 
 structure, are sometimes referred to as crystalline solid solutions. 
 
 For solid solutions the term eutectoid (of the nature of or 
 resembling a eutectic) has now been generally adopted, although 
 "eutectic" is still sometimes met with for this particular case; 
 the terms aeolic or benmutic were suggested but have never 
 come into use. The terms eutropic mixture and eutropic point 
 (Rinne) were proposed to distinguish changes going on during 
 cooling after solidification from the eutectic changes during solidi- 
 fication itself. To indicate the similar changes leading up to the 
 formation of the eutectoid the upper point (and curve) is known 
 as the liquidoid and the lower the solidoid. 
 
 Cooling of Solid Solutions. As illustrated by the iron-carbon 
 
METALLOGRAPHY 
 
 271 
 
 diagram (Fig. 38), changes, known as transformations, inversions, 
 thermal metamorphisms, or transitions occur similar to those on 
 freezing, giving rise to what are termed transformation curves. 
 Where there is a eutectoid, formed by the excess substance being 
 expelled from the solid solution, there is a selective transfor- 
 mation; constituents formed before the eutectoid are called 
 pro-eutectoid, those afterward, post-eutectoid ; in the case of 
 iron-carbon alloys the latter is also referred to as the pearlite or 
 sub -transformation range. 
 
 Iron-Carbon Diagrams. These are also referred to as equi- 
 librium, state, or constitutional diagrams because they serve to 
 illustrate what "states are normal under different conditions of 
 temperature and concentration (composition). Howe (Metallog. 
 of Steel) points out that such a diagram is made up of two parts : 
 
 1 
 
 Molten Jron 
 
 2 ^*\ >> ^ ( Fer Fondu ) 
 
 Molten Iron 
 
 (Fer Fondu) 
 
 Austenite 
 
 Anstenite + Cementite 
 
 Cementite 
 
 + 
 Pearlite 
 
 01 2345 
 
 Carbon Per Cent 
 
 FIG. 38. Constitutional diagram for iron-carbon alloys. 
 (I.A.T. M.) 
 
 an underscored V for the eutectic portion and another under- 
 scored V for the eutectoid portion. This forms a basis for one 
 classification of iron-carbon alloys: with 4.30% carbon there is 
 eutectic cast iron; with more carbon, hyper-eutectic cast iron; 
 with less carbon, hypo-eutectic steel and cast iron. Considering 
 the lower V, with carbon about 0.85% there is eutectoid steel; 
 when the carbon is greater, hyper-eutectoid steel; and if less, 
 hypo-eutectoid steel (this also applies to the matrix of cast iron, 
 i.e., exclusive of any graphite). As cementite is metastable 
 while graphite is stable, there are two forms of diagrams, (a) the 
 iron-cementite or metastable diagram, and (ft) the iron-graphite 
 or stable diagram. In Fig. 38 is shown the iron-cementite dia- 
 gram appearing in the report of Committee 53 of the Inter- 
 national Association for Testing Materials (I. A. T. M. diagram). 
 Various diagrams have been gotten up by the following: Iron- 
 
272 METALLOGRAPHY 
 
 carbon Benedicks (Sauveur, Metallography, 446), Carpenter and 
 Keeling (ibid., 445), Gutowsky, Mannesmann (considered by 
 Howe to be the earliest), Rosenhain (Sauveur, 447), Ruff (ibid., 
 449), Roozeboom (ibid., 444), Roberts -Austen (ibid., 442-3), 
 Sauveur (ibid., 441), Wittorff (ibid., 450), Upton (ibid., 448); iron- 
 phosphorus Desch (/. /. & S., 1915, 1, 195), Konstantinoff 
 (ibid., 194), Saklarwalla (ibid., 193). 
 
 Constituents of Iron Alloys. i. Ferrite (Howe): first used for 
 pure iron, now employed to designate that part of iron or steel 
 containing no carbon (or only a trace) in solid solution. It has 
 been suggested by Stead that ferrite when consisting of practi- 
 cally pure iron should be called ferro -ferrite. When the iron is 
 associated with considerable quantities of substances with which 
 it forms solutions or isomorphous mixtures, such as phosphide of 
 iron, or nickel, aluminum, manganese, silicon, chromium, vana- 
 dium, etc., they should be called respectively phospho-ferrite, 
 nickel-ferrite, alumino-ferrite, mangano-ferrite, silico -ferrite, 
 chromo-ferrite, vanado-ferrite, etc. (i) alpha (a) iron is pure 
 iron in its normal condition below Ar 2 (750 C., 1382 F.). It 
 crystallizes in the cubic (isometric) system; is strongly magnetic 
 (I. A. T. M.). It cannot dissolve carbon or only to a very limited 
 extent. (2) Beta (/3) iron, according to Osmond, is an allotropic, 
 non-magnetic variety of pure iron, existing at temperatures 
 between Ar 2 (750 C., 1382 F.) and Ar, (860 C., 1580 F.). It is 
 isomorphous with alpha iron, crystallizing in the cubic system. 
 When beta iron changes to alpha iron, heat is evolved and mag- 
 netic properties are developed. The term was formerly applied 
 to iron at all temperatures above Ar 2 (I. A. T. M.). It has the 
 property of dissolving carbon to a limited extent. Gamma (7) 
 iron, according to Osmond, is an allotropic, non-magnetic variety 
 of pure iron existing at temperatures above Ar^ (860 C., 1580 F.). 
 It crystallizes in the cubic system, and in crystalline forms of the 
 cube and the octahedron (but more frequently of the octahedron) 
 derived from the cube. In passing from the state of gamma iron 
 to that of beta iron an evolution of heat occurs (I. A. T. M.). A 
 fourth allotropic modification, delta (5) iron was claimed by New- 
 all in 1887 and Tomlinson in 1888. The transformation point 
 was supposed to occur at about 1000 C. Recenty G. Rumelin 
 and K. Fick (Ferrum, also /. /. & S. /., 1915, 1, 622) state that, in 
 investigating the iron-manganese system, they have detected 
 the 5-7 transformation. Free iron was the term proposed by 
 Sorby. The ferrite contained in pearlite is referred to as pearlitic 
 ferrite, eutectoid ferrite, or pearlite ferrite; when not so com- 
 bined, free ferrite, massive ferrite, excess ferrite, surplus ferrite, 
 non-eutectoid ferrite, structurally free ferrite; what separates 
 out before pearlite is formed, pro -eutectoid ferrite. Total ferrite 
 refers to all the ferrite present both free and associated. 
 
 2. Cementite (Howe): a carbide of iron having the formula 
 Fe 3 C. It (and the form of carbon) is also termed Abel's carbide 
 of iron, carbon of normal carbide (Ledebur), reheated carbon 
 (Osmond and Werth), carbon of cementation (Caron), cementa- 
 tion carbon, cement carbon, carbon of annealing, normal carbide, 
 
METALLOGRAPHY 273 
 
 carbide carbon, cementite carbide. Cementite may exist in fine 
 granules, thin plates, or in comparatively large masses in steel and 
 pig iron. According to Osmond it is the hardest constituent in 
 metal and steel, not colorable by polishing and etching with 
 various reagents (except sodium picrate see Etching below). 
 Sauveur distinguishes segregated cementite and free cementite 
 (also called non-eutectic cementite, surplus carbide, massive 
 cementite) : the former is a constituent of pearlite while the lat- 
 ter occurs independently. As the etrm "segregated" suggests 
 separation, and as one authority has called free cementite "segre- 
 gated," it appears advisable to substitute the term pearlite- 
 cementite (I. A. T. M.), pearlitic cementite or eutectoid cemen- 
 tite, free cementite is also called non-eutectoid cementite, 
 structurally free cementite or excess cementite. The cementite 
 in the eutectic (when it freezes) is called eutectic cementite. Howe 
 suggests for the cementite which separates before the eutectic is 
 formed, the terms pro-eutectic or primary cementite, and as an 
 analogy for the cementite which may separate before the eutec- 
 toid, the term pro-eutectoid cement. Sauveur suggests the 
 terms alpha cementite for the variety insoluble in iron, and 
 gamma cementite when it is soluble; this latter variety has also 
 been called regular cementite or solvite. Total cementite refers 
 to all that may be present, both free and associated. 
 
 3. Pearlite (Howe). A eutectoid of cementite and crystal- 
 lized iron formed by slow cooling past Ar\. Also called pearly 
 constituent (Sorby), pearlyte (Howe), perlite (Osmond), cryo- 
 carbide (Arnold). When pure it contains approximately 0.89% 
 Varbon. Steel containing about this percentage of carbon 
 (known as the structural saturation point), is called eutectoid 
 steel, aeolic steel, benmutic steel, eutectic steel, and saturated 
 steel; if more than this, hyper-eutectoid, hyper-aeolic, hyper- 
 eutectic, or supersaturated; if less than this, hypo -eutectoid, 
 hypo-aeolic, hypo -eutectic, or unsaturated. It consists of alter- 
 nating plates of cementite and ferrite or possibly sorbite (see 
 below), or grains of cementite embedded in ferrite or possibly 
 sorbite ([. A. T. M.). Normally pearlite should consist of 6.4 
 parts of ferrite to i part of cementite (by weight), but it should 
 be regarded, however, as a variable mixture, for in structuaal 
 steels containing between 0.5 and 1.0% manganese, the carbon 
 in pearlite varies between 0.6 and 0.9%, and in some tool steels, 
 according to the method of treatment, the pearlite, accompanied 
 by free cementite, may contain i% carbon (Stead). The range 
 of temperature throughout which pearlite can form is known as 
 the pearlitic range. A\ is essentially a pearlite point while the 
 upper limits of hypo-eutectoid steel are ferrite poults and the 
 upper limit of hyper-eutectoid steel is a cementite point. The 
 structure of pearlite depends upon the nature of the cooling 
 which it has undergone. If the cooling is rapid the structure loses 
 distinctness and is called by Arnold sorbitic pearlite (usually 
 considered as sorbite, see below) ; with slower cooling the struc- 
 ture is distinct and is termed true pearlite or by Arnold, normal; 
 with still slower cooling the structure is coarsened and is known 
 18 
 
274 
 
 METALLOGRAPHY 
 
 as laminated pearlite. If the temperature is held for some time 
 just below the lower critical, the two constituents tend to sepa- 
 rate into globules, kn&wn as spheroidizing or divorcing (divorcing 
 annealing) (Howe) and the structure is termed globular, granu- 
 lar or beaded pearlite (Benedicks). In examining a piece of 
 native iron, Benedicks discovered a structure which he classed 
 as a new micrographic constituent and named oxide pearlite. 
 
 4. Austenite (Howe). The following definitions are suggested 
 by H. M. Howe (T. A.I. M. E., XXIX (1908), 4-7)-: (a) Gener- 
 ically, the solid solution of iron carbide in iron, stable, for 
 
 STEEL 
 
 1500 
 
 AUSTENITE + CfMENTITE 
 Pro-eutectoid Cementite farms progressively 
 
 Ar 2 i Austenite here splits up into Pearlite = eutectold 
 rerrlte and cementite 
 
 CARBON 0.5 1.0 1.5 2.0 2.5 3.0 8.5 4.0 4.5 5.0 5^ 6.0 630.91 
 WON 100 99.5 99.0 98.5 98.0 97.5 97.0 96.5 96.0 95.5 95.0 94.5 ,94.0 S3.5 93.33 
 PERCENTAGE COMPOSITION 
 
 PIG. 39. The carbon-iron diagram. (Howe.) 
 
 instance, above the transformation range AI to A 3 . (b) Specific- 
 ally, this same solid solution as preserved in the cold, more or less 
 decomposed, for instance, by quenching steel containing more 
 than 1.5% of carbon from above 1100 C. in ice water. When 
 the structure of such steel is developed by polishing on parch- 
 ment moistened with licorice solution or ammonium nitrate after 
 reheating to 200 C., or by etching with hydrochloric acid in an 
 electric current, the austenite remains white while the zigzag 
 martensite with which it is often associated becomes brown. 
 Primary austenite, that which separates from the molten metal in 
 cooling through region 2 of Fig. 39. Primary cementite, that 
 
METALLOGRAPHY 275 
 
 which separates from the molten metal in cooling through region 
 3. Eutectic austenite, that which forms on crossing the bound- 
 ary aBc in cooling from region 2 or 3 into region 7, and forms part 
 of the eutectic. Eutectic cementite, that which forms on cross- 
 ing the boundary aBc from region 2 or 3 into region 7, and forms 
 part of the eutectic. Pro-eutectic ferrite, that which forms from 
 the austenite in cooling through region 5. It is the same as 
 excess ferrite. Pro-eutectic cementite, that which forms in the 
 austenite in cooling through region 7, and therefore immediately 
 precedes the eutectoid cementite, i. e., that of the pearlite formed 
 on cooling past Ar\. Primaustenoid, the network, spines, and 
 other masses rich in ferrite and therefore poor in carbon which in 
 hypo-eutectoid steel persist in undiffused relics of the primary 
 austenite formed in cooling through region 2. So long as they 
 persist, the heat treatment or the mechanical work which the 
 metal has undergone cannot be considered as complete, though it 
 may be sufficient for many purposes. Primaustenal, adj., of or 
 relating to primaustenoid. (For the above Howe claims no origi- 
 nality. He says the second to fifth are already in use in the pres- 
 ent or a similar form; he thinks the remainder distinctly new.) 
 The pro-eutectic ferrite is clearly that which Professor Sauveur 
 has called structurally free ferrite. Howe has hitherto called it 
 excess ferrite. The primary, eutectic, and pro-eutectoid cemen- 
 tite jointly form what Professor Sauveur has called struc- 
 turally free cementite, and Howe has hitherto called excess 
 cementite. Indeed, it is the need of subdividing this excess 
 cementite and assigning a specific name, pro-eutectoid, to that 
 which separates in cooling through region 7 that has led (him) to 
 propose the name pro-eutectoid ferrite instead of excess ferrite. 
 The former has the merit not only of matching the corresponding 
 cementite but of indicating the genesis. The eutectoid ferrite 
 and cementite are clearly those which result from the splitting 
 up of the hardenite and are habitually interstratified as pearlite. 
 The carbon dissolved in the austenite, and exclusive of any in the 
 form of cementite, has been termed dissolved carbon. 
 
 Austenite is sometimes called mixed crystals, gamma iron, and 
 (wrongly) martensite. Primary austenite is also referred to as 
 pro-eutectic. Primaustenoid is also called simply austenoid or 
 eutectic austenoid and saturated austenoid to indicate a content 
 of 1.70% C. Hardenite is the name given to austenite of eutec- 
 toid composition (0.9 % carbon), formerly classed as a special case 
 of martensite. Arnold and Read have shown that there are four 
 hardenites: iron hardenite (Fe 2 iFe 3 C), vanadium hardenite 
 (Fe72V4C 3 ), tungsten hardenite (Fe 2 eWC), ferro-molybdenum 
 hardenite (Fe 24 Fe 3 Mo3C). Edwards interpreted the term ther- 
 mal stability to mean the power which the hardenites possess of 
 resisting the softening action of heat when they are heated to 
 different temperatures. The range in temperature at which 
 austenite exists in known as the austenite range. The trans- 
 formation of hypo-eutectoid steel consists of two parts, the 
 selective part and the eutectoid part called also the austenite - 
 pearlite inversion or recalescence (Howe). A steel (usually cer- 
 
276 METALLOGRAPHY 
 
 tain types of alloy steel) which contains austenite is described as 
 austenitic; where free cementite is present, it has been called 
 cementito-austenitic ; if martensite is also present, austenito- 
 martensitic. 
 
 5. Martensite (Osmond). A transition form between austenite 
 on the one hand and ferrite and cementite on the other, prob- 
 ably containing all three of these substances, but in varying pro- 
 portions (Howe). It contains varying amounts of carbon up to 
 about i. 80%. The term hardenite was at one time used by 
 Howe for martensite of eutectoid composition (0.89% carbon), 
 and it was also employed for saturated martensite with 1.80% 
 carbon. It is harder than austenite and according to Osmond its 
 hardness is probably due to its containing beta iron. It is 
 magnetic; upon polishing, etching, and examining under the 
 microscope it has usually a characteristic structure of intersect- 
 ing needles parallel to the three sides of a triangle (acicular mar- 
 tensite). Howe and Levy found by certain treatments marten- 
 site resulted without this structure and suggested, provisionally, 
 the term emulsion martensite (non-acicular martensite), and 
 where a banded structure resulted, lamellar martensite. Gamma 
 martensite is the name sometimes given to the form existing only 
 above Ar\. It contains carbon dissolved in gamma, and prob- 
 ably also beta (Osmond) iron, this form of carbon being called 
 hardening carbon, hardening carbide, and martensite carbon. It 
 is obtained by rapid cooling from the austenite state or by ordi- 
 nary cooling with certain elements present which promote lag 
 (obstructive elements) such as nickel, manganese, etc. This 
 change to martensite has been termed by Howe martensitization. 
 According to Kroll martensite may be simultaneously osmoditic, 
 troostitic, or tempering. 
 
 6. Troostite. A transition form between austenite, and 
 cementite and ferrite, occurring while cooling through Arz. It 
 may be obtained by quenching while cooling through this point, 
 and also by reheating martensite at a low temperature consider- 
 ably below Ar\. Upon polishing, etching, and examining under 
 the microscope, it appears as dark colored masses somewhat 
 resembling in form peanuts or links of sausages. Kroll considers 
 it as deposited solvite more or less saturated with gamma iron 
 attached. It has been called by Arnold emulsified pearlite or 
 emulsified carbide. 
 
 7. Sorbite. A transition form between troostite and pearlite, 
 occurring while cooling through Ar\. It may be obtained by 
 quenching while cooling through this point and also by reheating 
 to a temperature a little above that for troostite but considerably 
 below what is necessary for the formation of pearlite. Upon 
 polishing, etching, and examining under the microscope, it 
 appears as a brownish colored constituent looking like blurred 
 pearlite, and for this reason has been called unsegregated pearl- 
 ite. It has been referred to by Arnold and Read as "pearlite 
 containing very finely granulated carbide." Sauveur says it is 
 now generally regarded as an uncoagulated mixture of the con- 
 stituents of troostite and pearlite. It apparently contains (i) 
 
METALLOGRAPHY 277 
 
 some hardening carbon, that is, carbon or carbide of iron dissolved 
 in beta iron, (2) a considerable quantity of alpha iron, and (3) 
 a considerable quantity of crystallized carbide of iron (cement 
 carbon). Howe terms sorbitism the condition when material 
 has a sorbitic structure, i.e., structural fineness, caused by 
 restraining the natural tendency of the structural components to 
 coalesce into larger and larger masses (pearlite), with progressive 
 deterioration of the quality. 
 
 8. Troosto-sorbite (Kourbatoff). This is troostite which has 
 not undergone as much transformation as sorbite, but there is no 
 sharp line of demarkation. 
 
 9. Osmondite (Heyn). Another homogeneous phase or transi- 
 tion product between troostite and sorbite closely related to the 
 preceding. It is essentially iron in a stressed condition (from 
 rapid cooling), with carbon in the form of hardening carbon. It 
 is also formed by reheating quenched material to about 400 C. 
 and is the condition in which iron is most soluble in dilute acids. 
 Benedicks' colloid hypothesis is that osmondite is a colloidal 
 solution of carbide of iron. 
 
 10. Steadite (Sauveur). In suggesting this name Sauveur 
 states that Stead writes that in very gray phosphoretic metals the 
 carbon diffuses out of it and a binary eutectic of FesP and Fe con- 
 taining in solution a little phosphorus is formed. Steadite, the 
 binary eutectic, according to Stead, contains about 10% (10.2%) 
 P and 90% (89.8%) Fe. 
 
 1 1. Ferronite (Benedicks) . " Benedicks, for instance, believes, 
 or at least believed at one time, that the pearlite ferrite of some 
 steels could contain as much as 0.27% carbon dissolved in beta 
 iron, whereas free ferrite is in the alpha condition. This car- 
 burized and allotropic ferrite Benedicks calls ferronite" (Sau- 
 veur). Guillet says that with steels under 0.27% carbon, the 
 ferrite may contain about 0.17% carbon as uncolored patches in 
 the pearlite. 
 
 12. Arnoldite (Stead). "If Dr. Arnold had not shown him- 
 self so very averse to having people's names introduced into 
 nomenclature he would have suggested that vanadium steels 
 ought to be called arnoldite steels, because really their wonder- 
 ful properties were first brought out and described by Professor 
 Arnold" (Stead). 
 
 13. Ledeburite (Wiist). The eutectic which cementite forms 
 with part of the austenoid aggregate and is comparable with 
 pearlite. It contains 52 parts by weight of cementite to 48 parts 
 of 1.70% austenoid (Howe). Bauer and Deiss describe it as the 
 mixed crystals (austenoid) cementite eutectic with 4.2 % carbon, 
 formed at a temperature of about 1130 C. It is produced by the 
 rapid cooling of white cast iron during or just below the point of 
 solidification. Alcoholic hydrochloric acid attacks the plates 
 of mixed crystals (with about 1.76% carbon) the same as marten- 
 site; the cementite plates are not attacked. 
 
 14. Graphite. Nearly pure carbon occurring in thin curved 
 plates and always amorphous. Graphite is the stable form of 
 carbon and the carbide (cementite) is the metastable form; cer- 
 
278 METALLOGRAPHY 
 
 tain conditions such as slow or prolonged heating or the presence 
 of certain elements, especially silicon, tend to produce the reac- 
 tion Fe 3 C = 3Fe + graphite, known as graphitization of cemen- 
 tite. A variety produced in malleable castings is called temper 
 carbon or annealing carbon. As opposed to this graphitic carbon, 
 Howe has proposed the term agraphitic carbon: that commonly 
 known as combined carbon, including both that dissolved in aus- 
 tenite and any present in cementite. 
 
 It may be repeated that the condition of carbon is (i) in solu- 
 tion above AI (or Aei) as hardening carbon, and (2) below 
 this point as cement carbon, or (3) in both cases in the free state 
 as graphite. In 1906 Sauveur expressed the opinion (Sauveur's 
 hypothesis of the allotropic transformations and of the dissolving 
 power of iron for carbon) that it was far from certain that the 
 liberation of iron from solution must precede, or at least be simul- 
 taneous with, the allotropic changes affecting the iron at certain 
 critical temperatures. The hypothesis was advanced that in 
 solution it might first undergo an allotropic modification and then 
 be expelled in its new allotropic form. It is evident that if the 
 allotropic transformation of iron from the gamma to the beta 
 and then to the alpha state precedes its liberation from solution, 
 three solid solutions of carbon in iron are formed during cooling, 
 namely, carbon (or Fe 3 C) dissolved (i) in gamma iron, (2) in 
 beta iron, and (3) in alpha iron. The first solid solution is 
 universally called austenite, while this hypothesis leads almost 
 irresistibly to regarding the solid solution in beta iron as marten- 
 site and the solid solution in alpha iron as troostite (Sauveur). 
 
 "G. Auchy (Iron Age, 1915, XCV, 50-51) propounds a chemical 
 theory to explain the different properties of iron-carbon steels on 
 the assumption of the existence of ferrated carbides (compounds 
 of iron and carbide of -iron). The carbides, which it is suggested 
 are factors in the problem, are: cementite; the austenites (fer- 
 rated Fe 2 C compounds); the martensites (similar compounds); 
 and hardite (a ferrated Fe-C compound). According to the 
 chemical theory set forth the white -etching constituent of hyper- 
 eutectoid steels is never hard cementite (FesC) but always soft 
 austenite, and the white-etching constituent of hypo -steels 
 above 0.22% of carbon, never ferrite, but austenite. In cast 
 iron, hardite is an intensely hard, unstable, white-etching per- 
 carbide FeC-5Fe, containing 3.45% carbon, formed, if the 
 cooling be rapid, at about 1200 C. by the reaction of 1.76 carbon- 
 austenite upon 6.67 carbon-austenite-cementite. As a matter of 
 fact, the theory that austenites, martensites, and hardite are 
 definitely ferrated chemical compounds need not be insisted on, 
 and they might be regarded as solid solutions in indefinite pro- 
 portions of Fe s C, Fe 2 C, and FeC respectively in iron. At best, 
 the difficulty may be met by assuming definite ferration at solidi- 
 fication'^/. /. & S. L, 1915,11,317-8). To distinguish between 
 cementite which is nearly insoluble in dilute sulphuric acid, and 
 the soluble form of carbon found in osmondite and troostite, 
 Heyn suggested the latter be designated by the symbol Cf. 
 Miscellaneous Constituents. Following is a list of the princi- 
 
METALLOGRAPHY 279 
 
 pal constituents occurring in some cases as impurities or what 
 Hibbard calls sonims: "A solid non-metallic portion of matter 
 existing as an impurity in metal. A piece of sand, brick, clay, or 
 such material embedded in metal would be considered as a for- 
 eign body, not as an impurity, and therefore not a sonim." A 
 brief discussion of their occurrence will be given under Micro- 
 structure. Manganese sulphide, MnS; iron sulphide, FeS; iron 
 oxide, FeO, Fe 2 Oi, rarely Fe 2 Os; iron or manganese silicate, 
 various proportions; iron phosphide, Fe 3 P and Fe 2 P; iron silicide, 
 FeSi; various carbides either free or partially replaced by iron, 
 as manganese carbide, MnsC, also (FeMn)sC; chromium carbide 
 Cr 2 Cs, etc. Kirner claims to have found a constituent in steels 
 rich in nitrogen which he calls flavite, perhaps iron nitride, 
 
 Hardening Theories. Various explanations have been offered 
 to attempt to explain why steel may at one time be soft and at 
 another hard. Howe states that "Hardening is usually due to 
 martensitization, that is, to enabling the transformation to pro- 
 ceed to but not past the martensite stage, either (i) by cooling car- 
 bon steels rapidly from the austenite state; or (2) by the presence 
 of such an intermediate proportion of the obstructing elements, 
 carbon, nickel and manganese, as to cause the transformation to 
 reach only this stage even in slow cooling; or (3) by bringing it 
 to this stage by subcooling cold austenitic steel, e.g., in liquid air; 
 or (4) by overstraining austenitic steels by cold deformation, so 
 as to stimulate the overdue change from the austenitic to the 
 martensitic state. In addition to these four martensitizing 
 methods of hardening there are two others, which we may call (5)- 
 and (6). (5) is the hardening of austenitic steels by a regulated 
 reheating, which gives mobility enough to allow the transforma- 
 tion to go as far as the hard intermediate state, but not enough to 
 let it reach the final alpha state. This hardening does not always 
 cause martensitization. (6) is the hardening of the malleable 
 metals and alloys in general, gamma and alpha iron included, by 
 plastic deformation. There is neither evidence nor reason for 
 believing that this usually acts through martensitization, except 
 in the case of gamma iron" (Metallography of Steel and Cast Iron, 
 176-7). Howe calls groups (i) to (5) the reversing class, and 
 (6) the cumulative class; (i), (3) and (4) are also referred to as 
 dynamic. Sauveur (Metallography and Heat Treatment of Iron 
 and Steel, p. 308) makes a general division into retention theories 
 (where a former state is more or less preserved) and stress 
 theories; he also refers to solution theories which involve 
 some form of solid solution (sometimes referred to as forced 
 solution), and carbon theories where carbon as such (or in com- 
 bination) is assumed to be responsible. 
 
 Osmond's theory, also referred to as the allotropic, beta or 
 beta iron theory is based on the assumption that in passing from 
 the gamma state above Ar 3 , to the alpha state below Ar\, some 
 of the iron is retained in the hard beta form. Osmond states, "I 
 conclude that hardened steel owes its properties principally to 
 the presence of beta iron, which is hard and brittle by itself at 
 
280 METALLOGRAPHY 
 
 the ordinary temperature." In view of certain results of Had- 
 field and Hopkinson, Howe suggests the possibility that "in 1 
 addition to the non-magnetic beta iron as we know it above A 2 , 
 . . . there is a fourth allotropic form, hard and yet magnetiz- 
 able in strong fields which we may call beta II. On this hypothe- 
 sis, . . . the transformation is really divisible into two parts, 
 so that the hard state . . . represents beta I mixed with 
 gamma, and that of quenched steel represents beta II mixed with 
 alpha" (Metallography of Steel, 186). Again (p. 196), in regard 
 to the beta theory or hypothesis, "that it is a distinct beta state 
 or states of iron, coordinate with the end states gamma and alpha. 
 Gamma iron alone is dense, beta I and II alone are hard, and 
 beta II and alpha alone are magnetic, both gamma and alpha 
 being isolated easily, but beta thus far always occurring mixed 
 with either gamma or alpha or more often both." Benedicks' 
 theory is that so-called beta iron is really a solution of gamma fer- 
 rite in alpha ferrite. The gamma or gamma iron theory ignores 
 the existence of beta iron and assumes that a certain amount of 
 gamma iron is preserved in solution in alpha iron. The alpha or 
 alpha iron theory of LeChatelier and Guillet is that in cooling, 
 carbide of iron is retained in solution in alpha iron. 
 
 The carbon theories of hardening are directly opposed to the 
 preceding, being based on the contention that the hardening is 
 the result of the carbon, per se, and not directly at least to any 
 allotropic condition of the iron. In support of this view it is 
 pointed out that without any carbon iron cannot be usefully 
 hardened, while the effect increases with increase in carbon, at 
 least to a certain point. The hardening carbon theory asserts 
 that above A 3 the carbon exists in, and imparts to the steel, a 
 hardened condition which can, in part at least, be retained when 
 cold by sufficiently rapid cooling. Arnold's sub-carbide theory 
 supposes the existence above A 3 of a sub-carbide having the 
 formula Fe 2 4C, called hardenite, which is very hard, and if 
 retained when cold imparts this property to the steel. There 
 was also the diamond theory, that hardness was produced, on 
 quenching, by the carbon being converted into minute diamonds 
 by the sudden compression of the metal. 
 
 The carbo-allotropic theory, in the nature of a compromise 
 between the two proceeding, is that hardening is due both to 
 the allotropic condition of the iron, and to carbon in solution, 
 probably as carbide but perhaps as simple carbon, which acts 
 as a brake on the transformation which is thus largely prevented 
 when the cooling through the transformation range is sufficiently 
 rapid. 
 
 Stress Theories of Hardening. In this connection a careful 
 distinction must be made between (a) macroscopic strain, that 
 produced by irregularities of cooling a mass or object, which 
 affects different parts, and may result in actual rupture; and 
 (b) microscopic strain, which affects the component particles 
 of the grains. Akerman's theory, that hardening is due to 
 compressive strains alone (compression theory), set up by 
 quenching or other rapid cooling is no longer considered. 
 
METALLOGRAPHY 281 
 
 Beilby's theory was that the hardness in cold-strained metals, 
 as in the case of wire drawing or of polishing, was due to a 
 vitreous amorphous phase, or thermally metastable state, 
 sometimes referred to as Beilby's hard iron. Somewhat along 
 the same line, Rosenhain and Ewen ^uggest that the space 
 between the boundaries of crystal faces is filled with an amorph- 
 ous material or cement (see Plastic Deformation below). 
 Humfrey's amorphous theory is that this amorphous condition 
 is brought about by cooling rapid enough to prevent one crystal- 
 lized form to recrystallize (decrystallization) into the other 
 whereby there results an amorphous solution of carbide of iron 
 in alpha iron; the hardness would therefore be due not only to 
 that of the amorphous phase but also to the iron carbide solution. 
 The amorphous theory or stress theory in some form is also held 
 by Edwards and Carpenter, A. Le Chatelier, Grenet, and Charpy. 
 McCance's interstrain theory is somewhat similar as he claims 
 that there is a solution of carbon in alpha iron (transformed 
 from gamma iron) with some gamma iron; that the iron is 
 crystalline but in a condition of strain due to the arrangement 
 between the alpha and the gamma iron, for which he uses the 
 term interstrain to denote the condition of a metal after perma- 
 nent deformation of any kind; other writers have used the 
 terms internal tension and internal strain. 
 
 Plastic Deformation. When a metal is subjected to any kind 
 of static stress it is deformed (a) temporarily if the stress is 
 within the elastic limit, and (&) permanently if the stress is 
 above the elastic limit, provided, of course, it is plastic which 
 is the case, to a certain extent, at least, with all metals (see 
 Physical Properties, page 334). Such plastic static deformation 
 caused by overstrain, is due to an actual flow of the material. 
 Howe and Levy (T. A. I. M. E., L) distinguish four varieties; 
 (i) intergranular, where the several grains, each as a unit, move 
 with relation to each other; (2) intra-granular, where the par- 
 ticles of ferrite, cementite, or pearlite, each as a unit, move with 
 relation to each other; (3) intra-pearlitic, where the pearlitic 
 ferrite and cementite move with relation to each other; and 
 (4) crystal unit slipping, where the minute units move past 
 each other. Howe (Metallog. of Steel, 293-4) further divides 
 them into fluid movements, where the individual particles 
 move with relation to all the others, and block movements, 
 where the motion is by portions, the particles in each being 
 relatively stationary; the movement may also be crystalline, 
 if it is concerned with crystalline structure, and non-cry stalline 
 if without such regard; crystalline, again, may be rotary (change 
 of position and of orientation), and vectorial (change of position 
 without change of orientation). 
 
 Amorphous Cement Theory. Beilby's theory of crystalline slip 
 was that when a metal was overstrained it assumed a temporary 
 fluid or mobile state and then an amorphous phase or state 
 which was located between the crystal boundaries and acted as 
 a cement (this name seems appropriate as it requires an appre- 
 ciable time for it to "set") to bind them together (intergranular 
 
282 METALLOGRAPHY 
 
 cement), the amount being in proportion to the overstrain; this 
 cement is supposed to be much harder and stronger than the 
 crystalline material which it joins. This amorphous phase is 
 regarded by Rosenhain and others, from the point of view of the 
 phase rule, as identical with the liquid phase. This cement 
 or amorphous boundary filling may lead to what Howe terms 
 boundary or joint strength which in normal conditions leads 
 to rupture through the grains (transcrystalline) instead of 
 following (intergranular) the boundaries themselves. Rosen- 
 hain holds that there is a dendritic interlocking of the adjacent 
 grains which increases the strength when present; there is also 
 evidence (Howe) that there is contact confusion of orientation 
 (strong contact-metal theories). Howe points out (Metallog. 
 of Steel, 191-2) that amorphizing (becoming amorphous) may 
 be either mechanical by cold working or overstrain, or crystal - 
 lographic, by the occurrence of the transformation in cooling 
 at so low a temperature that, on the breaking up of the gamma 
 iron crystals by the transformation itself, the resultant alpha 
 iron particles cannot re-orient themselves and hence remain 
 amorphous. According to Howe and Levy (loc. cit.), while 
 Beilby's theory satisfactorily explains the phenomena of simple 
 overstrain (stress applied in one direction), it does not in the 
 case of reversing overstrain (first in one direction and then in 
 the opposite), as the former strengthens the metal and its effect 
 can be obliterated by annealing at a relatively low temperature, 
 while the latter does not strengthen the metal nor is its effect 
 obliterated by such treatment. 
 
 
 D D 
 
 A -Before Straining B- After Straining 
 
 PIG. 40. Diagram of the formation of slip bands (Rosenhain). 
 
 The work of Ewing and Rosenhain, followed by that of others, 
 has served to explain the mechanism of plastic deformation. 
 This occurs, when the local elastic limit has been exceeded, by 
 the slipping of one layer or portion of a crystal or grain over 
 another portion along slip planes, gliding planes or cleavage 
 planes (motion planes), an interstratal (between strata) move- 
 ment, producing what are known as slip bands (Ewing and 
 Rosenhain' s slip theory). These are shown in Fig. 40. (Rosen- 
 hain, Phys. Met., 243) "which is intended to indicate in a very 
 approximate manner the condition of a cross -section of two 
 adjacent crystals before and after plastic straining. The upper 
 sketch represents the unstrained crystals, whose smooth upper 
 (polished) surface is indicated by the line ABC the step at 
 B is the slight difference of level between adjacent crystals 
 formed as the result of etching; the boundary between the 
 
METALLOGRAPHY 283 
 
 crystals is represented by the full line BD, while the potential 
 planes of gliding or slip, differently oriented in each crystal, are 
 indicated by the dotted lines. After straining, slip has taken 
 place on some of these slip planes, and minute steps have con- 
 sequently been formed in the surface at the points marked 
 s, s, s in the lower figure these steps will, of course, slope in 
 different directions in different crystals. Seen from above, by 
 normal illumination, these short, steep, sloping surfaces will 
 appear simply as narrow black lines" (Rosenhain, Phys. Met., 
 243-4). Simple slip or primary slip is where only one has 
 occurred; secondary slip is where there has been further slipping. 
 As the straining is increased up to the point of rupture the bands 
 become more numerous and confused, with a roughening of the 
 surface apparent to the naked eye. This appearance is some- 
 times termed micro-flaws. The result of the internal strains 
 produced by plastic deformation is indicated by surface de- 
 formations or bands (flow lines or lines of stress), which have 
 been called Liiders lines, corresponding with slip bands; they 
 differ from the Neumann ban4s>or narrow twins (see Crystal- 
 lography, page 127) in that they are obliterated by etching. 
 
 1. Close order in line 2. Open order en echelon 
 
 FIG. 41. Varieties of slipping. 
 (Howe and Levy.) 
 
 Howe uses the term common lines (loc. cit., 298-9) and common 
 paths of deformation as those which are of the same family as 
 the theoretical, based on the nature and direction of the forces 
 acting; and specific lines or paths, those actually followed, 
 differing materially from the theoretic by reason of internal 
 surfaces of weakness. Howe and Levy (T. A. I. M. E., L, 542) 
 illustrate in Fig. 41 two types of slipping which they call 
 respectively close order in line and open order en echelon ; they 
 state that if the alternate strata are brittle, compression parallel 
 to the stratification converts the first into the second. 
 
 Howe states (Metallog. of Steel, 312-3) "In a given grain the 
 slip bands usually have a dominant direction, which may be 
 followed closely, as when the slip bands are both closely parallel 
 and nearly straight, or may be deviated from materially. In 
 this deviation the slip bands may remain nearly parallel, in 
 which case the deviation is of the whole system of slip bands, a 
 systematic deviation; or they may deviate independently of 
 each other, giving us individual deviations. By the terminal 
 grain boundaries I mean those toward which the dominant 
 direction of the slip bands runs ; by the lateral ones I mean those 
 along which it runs." Howe's explanation of Osmond and 
 Cartaud's Slip Band Theory is as follows (Metallog. of Steel, 
 339); it is "in effect incomplete twinning, a rocking or rotating 
 
284 METALLOGRAPHY 
 
 of the units which compose each of the slices of metal involved 
 in the movement, each unit about its right-hand side, together 
 with a lifting of each unit by its own rocking and by that of 
 those at its right. ... In this view there is no slip plane, but a 
 succession of gliding planes. . . . The direction of the motion 
 is approximately normal to the riser [of the step], instead of being 
 parallel to it as in simple slip. This may be called the wheeling 
 [slip theory] as distinguished from Ewing and Rosenhain's 
 slip theory of slip bands." 
 
 Metallographic Examination. The methods are as various 
 as opportunity offers or expediency indicates. They may be 
 classified into: 
 
 (1) Optical analysis: Determining the constituents, struc- 
 tures, forms, appearances, etc., by the eye alone or assisted by 
 suitable magnifying devices. 
 
 (2) Thermal analysis: A study of the nature of metals and 
 alloys by means of heating and cooling curves, changes in 
 specific heat, etc. 
 
 (3) Magnetic analysis: Determination of changes in nature 
 affecting the magnetic properties. 
 
 (4) Physical analysis: Determination- of the properties by 
 the usual methods of testing. 
 
 (5) Chemical analysis: Both proximate and ultimate; gen- 
 erally in conjunction with one of the other methods. 
 
 Optical Analysis. Also termed visual analysis. This is 
 divided into (a) macroscopic or megascopic analysis, which 
 relates to an examination of appearances sufficiently large to be 
 visible to the naked eye or when enlarged only a few diameters 
 (the dividing line usually being placed at about 5 diameters); 
 subjects which belong to this class are ordinary fractures, certain 
 structures, crystalline formations, etc.; (b} microscopic analysis 
 where minute structures require the aid of high magnifications; 
 there are various synonyms or associated terms; microscopy, 
 micrography, relating to the study of minute objects by the 
 aid of the microscope; micrology, practically the same as the 
 preceding, except that the examination need not always be visual; 
 micrometry, the measurement of minute objects, or quantities, 
 quantitative microscopy; microtechnique, the methods em- 
 ployed; metalloptric, N microscopy as applied to metals; micro- 
 metallurgy, micrology as applied to metals. The minute 
 characteristics are termed the micro -character, their formation 
 the microstructure ; where the structure is too minute to be 
 resolved by the most (or any but the most) powerful magnifica- 
 tion, it is said to be ultramicroscopic. Photographic reproduc- 
 tions are called photomicrograph (frequently erroneously micro- 
 photograph; this really means a photograph reduced to such 
 small size that it must be viewed through a magnifying glass); 
 micrograph, microphotogram (rare), photogram, and microgram. 
 The terms visual microscopy and photomicroscopy or photo- 
 micrography are sometimes used to distinguish respectively 
 between the use of the eye only and photographic reproduction. 
 A distinction is usually made (applying to macroscopic work) 
 
METALLOGRAPHY 285 
 
 between photograph and print; the former is a reproduction 
 by photographic means (that is, indirect), while the latter is 
 by direct contact with the object itself, as in the case of sulphur 
 prints. A form of microscope particularly adapted to the 
 examination of metals has received the special names metal- 
 lurgical microscope, metalloscope, and micrometallograph 
 A simple microscope is one which has only one lens (or set of 
 lenses), a compound microscope is one which has two such lenses, 
 one near the object (objective), and the other for the eye of the 
 observer (eye-piece). The ordinary or single microscope has 
 only one tube, etc.; the binocular or stereoscopic binocular 
 microscope consists of two instruments mounted to give a 
 stereoscopic (perspective) view. As metal specimens are opaque 
 the light to make the surface sufficiently visible (illumina- 
 tion) cannot be transmitted through them but must be directed 
 on the surface itself by a reflecting or refracting device called 
 an illuminator. Usually, particularly with very high powers, 
 the illumination is vertical or normal, that is, perpendicular 
 to the surface; in some cases to reveal irregularities in the surface 
 by throwing projections into relief, an oblique illumination 
 is employed where the light strikes at an angle less than 90 de- 
 grees. The picture of the object shown by the microscope is 
 termed the image. The power of a microscope is usually ex- 
 pressed in diameters, that is, the number of times the linear 
 dimension of an object is magnified. To resolve a structure is 
 to bring out its detail (constituents, etc.) by the use of a suffi- 
 ciently high power. Within the past few years the General 
 Eelectric Company has experimented with the x-ray for the 
 detection of internal defects, particularly of castings. Radio- 
 graphs, employing Coolidge tubes, have been made with con- 
 siderable success; stereoscopic radiographs have also been 
 made with a view to determining also the depth at which the 
 defects occurred. 
 
 Preparation of Specimens. Where high-power microscopes 
 are to be employed it is necessary to have a plane surface free 
 from all scratches, although for ordinary purposes very special 
 care and precautions are not always necessary. This is effected, 
 after preliminary preparation by cutting and filing, by polishing, 
 an operation consisting in applying various abrasives (such as 
 emery, rouge, etc.) of successive degrees of fineness until the 
 desired result is secured. It is naturally much more difficult 
 to remove all scratches in the case of very soft material on 
 account of its greater susceptibility to being affected by chance 
 specks of dust, etc.; great care must therefore be exercised to 
 maintain cleanly conditions and the specimen must be carefully 
 washed after each step to prevent any coarse abrasive from being 
 introduced into the next finer grade; it is also of assistance to 
 have the direction of polishing at each stage at right angles 
 to that of the preceding. Burnishing and buffing as ordinarily 
 applied are simply comparatively crude polishing operations to 
 produce a high luster on articles of jewelry, etc., and usually 
 result in myriads of fine scratches and also tend to smear the 
 
286 METALLOGRAPHY 
 
 metal on the surface. Certain constituents are revealed by 
 polishing alone owing to differences in coloration (this is par- 
 ticularly true of some non-ferrous alloys) such as graphite or 
 manganese sulphide, or where there is a marked difference in 
 hardness; by using a soft backing to carry the abrasive the softer 
 parts are worn away to a greater depth, forming a bas-relief 
 (relief polishing). The treatment with different chemical 
 reagents, etc., with a view to developing differences between 
 the various constituents by the coloration or appearance which 
 they assume and the degree to which they are corroded, is known 
 as etching. 
 
 Etching. This is usually done when the specimen is cold 
 (cold etching); however, methods have been advised for use 
 when the metal is at a high temperature (hot etching) in order 
 to develop the structure when in that condition. Etching to 
 develop the structure for subsequent examination under the 
 microscope may be termed microscopic or microstructure 
 etching; in contradistinction to this is macroscopic or macro- 
 structure etching, which is for the purpose of developing the 
 structure (such as segregation, porosity, seams, etc.) by examina- 
 tion by the eye alone. H. Le Chatelier divides etching methods 
 or reagents into three classes : (a) where superficial combination 
 with the metal takes place, no solution occurring; (6) where the 
 metal is dissolved and effects a simultaneous deposition of another 
 metal; (c) where there is simple solution, the crystal surfaces 
 being developed. While "etching" connotes a corroding 
 process, other methods, such as heat tinting, owing to the simi- 
 larity of their purpose, are usually, and conveniently, included 
 in this classification. The various methods employed may also 
 be classified as follows, according to the means employed: 
 
 1. Mechanical methods: Polishing alone; the softer constitu- 
 ents are worn away to a greater depth. 
 
 2. Chemical methods: The different constituents are differ- 
 ently affected in corrodibility or coloration. 
 
 3. Mechanico-chemical methods : Simultaneous abrading and 
 corroding action. 
 
 4. Electrolytic methods: An electric current is employed to 
 assist in the corroding action. 
 
 5. Heating methods: Thin oxide films of different thicknesses 
 are produced, resulting in different colorations, or other reactions 
 are caused. 
 
 6. Deposition methods: Certain constituents are coated by 
 the deposition of another metal in solution, with or without the 
 assistance of an electric current. 
 
 7. Printing methods: This is included although perhaps 
 belonging more properly under methods of examination. It 
 consists in applying a chemical reagent which reacts on one of 
 the constituents to form a compound which, in turn, reacts on 
 a second reagent applied on a sheet of paper or cloth applied 
 directly to the surface of the specimen. 
 
 Mechanical Methods of Etching. As already mentioned 
 these consist in using a very soft backing for carrying the abra- 
 
METALLOGRAPHY 287 
 
 sive; they are principally used with non-ferrous alloys where 
 there is a marked difference in hardness between the various 
 constituents. 
 
 Chemical Methods of Etching. BaykofPs method, for hot 
 steel, is to employ hydrochloric acid (HC1) gas. Benedicks' 
 reagent: 5% solution (ale.) of metanitrobenzol sulphonic acid; 
 darkens martensite more than austenite. Heyn's reagents: 
 
 (a) copper-ammonium chloride: 10 grams in 120 c.c. water; 
 
 (b] also ammoniacal copper-ammonium chloride: as in (a) with 
 sufficient ammonia (NEUOH) added to dissolve -the blue 
 precipitate which first forms; (c) (with Martens) alcoholic 
 hydrochloric acid: i c.c. hydrochloric acid (1.19) in 100 c.c. 
 absolute alcohol. Hilpert and Colver-Glauert's reagent: sul- 
 phurous acid; 3 to 4% of a saturated aqueous solution of sulphur 
 dioxide in water or alcohol. Igewsby's (Ischewski) reagent: 
 5 grams picric acid in 100 (also given as 95) c.c. absolute alcohol. 
 Jones' reagent: molten zinc; after immersion any adherent 
 zinc or dross removed partly by mechanical means and partly 
 by dilute sulphuric acid. Kourbatoff's reagents: (a) 3% 
 (about) aqueous solution of sodium picrate with an excess of 
 caustic soda (NaOH); solution to be used boiling; (b) nitric 
 acid in a solution consisting of a mixture of various alcohols 
 etc. H. Le Chatelier's reagents : (a) an acidulated aqueous 
 solution of ferric chloride; (b) an aqueous solution of potassium 
 bitartrate; (c) a mixture of equal parts of a 50% aqueous 
 solution of sodium carbonate and a 10% aqueous solution of 
 lead nitrate; (d) glycerine for composing the solution with nitric, 
 hydrochloric, or picric acid; (e) phosphorus reagent, consisting 
 of: absolute methyl alcohol, 100 c.c., cupric chloride (CuCl 2 , 
 2H 2 O) i gram, magnesium chloride (MgCl 2 , 6H 2 O), 4 grams, 
 HC1 (cone.) 2 c.c., H 2 O, 18 c.c. Martens' reagents: (a) 4c.c. 
 nitric acid (1.14) in 100 c.c. absolute alcohol; (b) see Heyn's 
 reagents. Matweieff's reagent: boiling, neutral, aqueous solu- 
 tion of sodium picrate. Osmond's reagents: (a) tincture of 
 iodine; (b) 10 % aqueous solution of hydrochloric acid. Portevin's 
 method : etching first in a solution of 10 grams copper-ammonium 
 chloride in 120 c.c. water, followed by use of 10% solution of 
 nitric acid in water. Robin's reagent: saturated alcoholic 
 solution of picric acid. Rohl's reagent: for ferrous sulphide 
 (FeS), i% ^,myl alcohol solution of organic acids. Saniter's 
 reagent: molten calcium chloride for hot etching. Sauveur's 
 reagent: concentrated ntiric acid washed off in a stream of 
 water. Sorby's reagent: very dilute aqueous solution of 
 nitric acid. Stead's reagents: (a) for phosphorus, cupric 
 chloride, 10 grams, magnesium chloride, 40 grams, hydrochloric 
 acid 20 c.c., alcohol, q. s., 1000 c.c.; (b) 20% sulphuric acid, 
 followed by cleaning in nitric acid. Whiteley's reagent: for 
 phosphorus, 0.04 gram cupric oxide (CuO) dissolved in 6 c.c. 
 of strong nitric acid and methylated spirits added to make up 
 200 c.c. Yatsevitch's reagent: for high speed tool steel, 10 c.c. 
 hydrogen peroxide solution (commercial) mixed with 20 c.c. of 
 a 10% aqueous solution of sodium hydrate. 
 
288 METALLOGRAPHY 
 
 Mechanico-chemical Methods of Etching. The method 
 originated by Osmond is termed polish-attack (sometimes 
 attack-polishing and polish-etching) and at first consisted in 
 rubbing the specimen on parchment (stretched on a board) 
 soaked with an aqueous extract of licorice root and calcium 
 sulphate; later Osmond and Cartaud substituted a 2% aqueous 
 solution of ammonium nitrate. 
 
 Electrolytic Methods of Etching. These consist, in general, 
 in making the specimen the anode and employing a very weak 
 current, the electrolyte being composed of various substances. 
 The cathode is usually a strip of platinum or a platinum dish 
 used as the container. They may be considered modifications 
 of the strictly chemical methods. Martens and Heyn employ 
 i c.c. of hydrochloric acid in 500 c.c. of water; Osmond recom- 
 mended a gentle current in connection with his chemical method 
 (&). Weyl's method belongs to this class. 
 
 Heating Methods for Developing Structure. Heating a speci- 
 men in hydrogen, air, etc.., to develop the structure on a polished 
 surface, by oxidizing or otherwise affecting the different constitu- 
 ents, originated with Osmond (heat relief), and was perfected 
 by Stead especially in his researches on phosphorus, and con- 
 sisted in heating in air after a brief preliminary treatment 
 with dilute acid; termed heat tinting, temper tinting, or air 
 tinting. 
 
 Deposition Methods of Etching. Rosenhain and Haughton's 
 reagent: ferric chloride (Fe2Cle,) 30 grams, HC1 (cone.) 100 c.c., 
 cupric chloride (CuClz), i gram, stannous chloride (SnC^), 
 0.5 gram, H 2 O, i liter; a film of copper is deposited, the thickness 
 (and coloration produced) varying with the different constituents. 
 
 Printing Methods. These methods are used to illustrate the 
 macrostructure. A method, termed nature printing, has been 
 used to a limited extent; the surface is deeply etched with a 
 suitable reagent from which prints (nature prints) are taken with 
 ink as from a wood block or copper etching in -ordinary printing 
 work. A method for making sulphur prints was devised by 
 Heyn and Bauer : a piece of silk, wet with a solution containing 
 mercuric chloride and hydrochloric acid, is pressed on the 
 polished surface of the specimen; the acid acts on any sulphide 
 present, generating H2S which, in turn, reacts with the mercury 
 salt to form the black precipitate of sulphide of* mercury; the 
 location and intensity of the stains indicate the position and 
 (roughly) the extent of the sulphur present. Baumann's 
 method replaces the silk with ordinary photographic paper 
 moistened with dilute sulphuric acid, the hydrogen sulphide 
 generated forming similar dark spots by reacting with the 
 silver salt. Law applies a coating of gelatine impregnated with 
 an acid solution of a soluble salt of lead, mercury, or cadmium 
 which forms a discolored precipitate as before; the result is 
 viewed under the microscope. Roger's method is designed for 
 the examination of fractures; it consists in backing an emulsion 
 of gelatine and silver bromide with clay which, after dipping in 
 acid, is applied and then withdrawn. 
 
METALLO-METALLIC COMPOUND METALLURGY 289 
 
 Structures. The macrpstructure may be sufficiently revealed 
 by simply cutting the desired section, as in the case of blowholes, 
 pipes, and cracks; cutting and then polishing when the details 
 sought are smaller or more obscure; etching to reveal so-called 
 flow lines which indicate to a certain extent the working to which 
 the material has been subjected, particularly in the case of cold 
 working or where the material has been severely distorted, in 
 this latter case assisted by the lines of slag (wrought iron) or 
 manganese sulphide if much is present. The macrostructure 
 may also reveal the presence of foreign substances, such as 
 inclusions of dirt or slag in steel, or of pieces of steel is wrought 
 iron ^see also Fractures). The microstructure is made up of 
 crystals or grains (see Crystallography) which, in turn, are 
 composed of constituents whose presence and arrangement 
 will depend upon the composition and heat treatment. Various 
 types of structure are considered more generally under Crys- 
 tallography. Non-metallic inclusions, such as slag, manganese 
 sulphide, etc., are detected by the absence of a metallic luster 
 when polished. Manganese sulphide usually has a dove-gray 
 color; owing to its lower melting point, it occurs in globules 
 in castings, and also because of its plasticity, drawn out as rods or 
 strings in worked material. Arnold has given the names sulphide 
 areas and sulphp -films to microscopic constituents containing 
 sulphur. Sometimes there is present what is termed a banded 
 structure, consisting of a series of bands or lines of ferrite, 
 white or slightly discolored, and frequently containing such 
 inclusions. These lines are termed ghosts, ghost lines, ferrite 
 ghosts, phantoms, shadow lines, or ghost structure; if very 
 minute, micro-ghosts or micro-ghost lines. These lines are 
 usually considered as due to dissolved phosphorus which has 
 expelled all carbon on slow cooling, hence sometimes referred 
 to as phosphorus banding; Stead calls white ghost lines those 
 whose appearance he considers due to cooling too rapidly to 
 prevent the expulsion of all carbon from the more phospborized 
 areas. Howe states (Metallog. of Steel, 563) in regard to what he 
 terms the incompatibility theory: "some seem inclined to ex- 
 plain these phenomena by a supposed incompatibility between 
 carbon and phosphorus, so that austenite migrates away from 
 the phosphoric bands when within the transformation range, 
 and that cementite does when below that range. In support of 
 this the slower cementation of phosphoric than of non-phos- 
 phoric iron may be cited.'' A considerable quantity of phos- 
 phorus may occur in solution in the ferrite; it may also appear 
 free (free phosphide) as an iron phosphide forming a eutectic 
 (particularly in the case of high phosphorus cast irons). 
 
 Metallo -metallic Compound. See Alloy. 
 
 Metalloid. See page 83. 
 
 Metalloptric (rare). See page 284. 
 
 Metalloscppe. See page 285. 
 
 Metallurgical Microscope. See page 285. 
 
 Metallurgy. The commercial production, preparation and treat- 
 ment of metals and alloys. 
 19 
 
2 QO METALM AN METEORITES 
 
 Metalman (obs.). A worker or dealer in metals. 
 Metamagnetic Alloy. See Alloy. 
 Metamerism. See page 85. 
 
 Metamorphic Theory. Of hardening; carbon theory: see page 279. 
 Metamorphism. See page 122. 
 Metaral See page 264. 
 Metastable Diagram. See page 271. 
 Metastable Equilibrium; Range. See page 269. 
 Metathetical Reaction. See page 87. 
 Metcalf s Experiment. See page 214. 
 Meteoric Iron. See page 291. 
 Meteoric Stone. See page 291. 
 
 Meteorites. Mineral and metallic bodies of extra-terrestrial 
 origin found on the earth's surface. They are recorded accord- 
 ing to their geographical location (nearest town, etc.) and, when 
 known, the date of their fall. When discovered by means of 
 their flight they are called falls; if detected from the nature of 
 their structure, finds. According to their form they may be 
 designated codonoid, bell-shaped; conoid, cone-shaped; cricoid, 
 ring-shaped; gnathoid, jaw-shaped; onchnoid, pear-shaped; 
 ostracoid, shell-shaped; peltoid, shield-shaped; styloid, columnar 
 etc. 
 
 There are three grand divisions : 
 
 I. Aerolites : consisting largely of stony matter (principally 
 silicates), and usually also of a slight amount of metallic 
 matter. 
 
 II. Siderolites: a transition group, composed of nearly equal 
 parts of stony and of metallic matter, with the metallic 
 portion generally in a sponge-like mass enclosing the stony 
 material in the pores. 
 
 III. Siderites: essentially metallic, in the form of an alloy 
 composed principally of iron with which nickel and cobalt 
 are always associated, and frequently also gold, platinum, 
 lead, and some of the rarer elements such as gallium, 
 selenium, palladium, etc. 
 
 The chemical composition varies widely, as is shown by the 
 following analyses : 
 
 Aerolite (Fayette County) : 
 
 SiO 2 37-70% 
 
 Fe 3-47 
 
 FeO 23.83 
 
 A1 2 O 3 2.17 
 
 P 2 Os 0.25 
 
 CaO 2.20 
 
 MnO 0.45 
 
 MgO 25.94 
 
 NiO 1.59 
 
 CoO 0.16 
 
 Co 0.09 
 
 s.. 1.30 
 
METEORITES 291 
 
 Siderolite (Liana del Inca) : 
 
 Metallic Earthy 
 
 Fe 89.77% SiO 2 28.08% 
 
 Ni 9.17 A1 2 O 3 12.74 
 
 Co 0.61 FeO 42.52 
 
 NiO 2.90 
 
 MnO 0.20 
 
 CaO 9.33 
 
 MgO 1.98 
 
 P 2 O 6 2.25 
 
 Siderite: 
 
 (Welland) (Puquois) 
 
 Fe 91.17% 88.67% 
 
 Ni 8.54 9-83 
 
 Co 0.06 0.71 
 
 S 0.07 0.09 
 
 Cu 0.04 
 
 P 0.17 
 
 Si Tr. 
 
 C . . . : o . 04 
 
 Variods other names and classifications have been used or sug- 
 gested. The terms aerolite, siderolite (abbreviated from aero- 
 siderolite), and siderite (abbreviated from aerosiderite) were 
 suggested by Maskelyne; Daubree proposed siderites for those 
 that contained iron, and asiderites for those which did not; sider- 
 ites were again divided with decreasing contents of iron into holo- 
 siderites (all iron), syssiderites, and sporadosiderites (traces). 
 Siderites are also termed irons and iron meteorites; aerolites 
 stones, stone meteorites or meteoric stones; while siderolites, a 
 transition between the other two, may be known as iron stones, 
 iron-stone meteorites, lithosiderites or mesosiderites. 
 
 The metallic iron in meteorites may be referred to as meteoric 
 iron in contradistinction to- ordinary or terrestrial iron. The 
 study of this subject has been called aerolitics (Maskelyne), 
 astrolithology (Shepard), and meteoritics (Farrington). 
 
 The physical structure as revealed by the microscope after 
 polishing and (sometimes) etching varies widely, and a great 
 many distinct classes are recognized, of which the most important 
 for the siderites are as follows : 
 
 (i) Octahedrites, or those with an octahedral structure com- 
 posed of two sets of parallel lines at right angles to each other, 
 called the Widmanstatten (or Widmanstattian) structure or 
 lines. These lines are due to the presence of three distinct iron- 
 nickel alloys, known as th^ triad : (a) kamacite, a broad central 
 band (containing from 4.8 to 7.4% of nickel), with narrow borders 
 of (6) taenite (containing from 16.7 to 38.1 % of nickel), and filling 
 in 'the interstices or fields where these bands intersect, (c) 
 plessite, a mixture of the other two. The most prominent of the 
 secondary structures which occur in the fields are referred to as 
 combs. 
 
292 METEORITES 
 
 (2) Hexahedrites, or those with a cubic (isometric) structure or 
 cleavage, composed of lines intersecting at an angle of 120, also 
 formed by the triad, and known as the Neumann bands or lines. 
 
 (3) Ataxites, or those having an interrupted or indistinct struc- 
 ture. 
 
 For a complete list of the various minerals and non -metallic 
 substances found, some comprehensive treatise should be con- 
 sulted such as those by Cohen or Farrington. 
 
 Aside from the triad there are various other alloys, of which the 
 more important are: 
 
 Cohenite, from the Magura meteorite, corresponds to the for- 
 mula (Fe, Ni, Co) 3 C, and from the Glorietta Mountain meteorite 
 (Fe, Ni, Co) 4 C. 
 
 Troilite, iron sulphide, FeS, usually found as separate nodules, 
 but occasionally in bands or plates. 
 
 Rhabdite, a phosphide of iron and nickel, sometimes containing 
 cobalt, for which the formula is (Fe, Ni) 3 P. 
 
 Daubreelite, a sulphide of iron and chromium. 
 
 Lawrencite, a protochloride of iron, generally found as an 
 excrescence. 
 
 Schreibersite, a phosphide of iron and nickel; the composition 
 is, as a rule, constant, and is expressed by the formula (Fe, Ni 
 Co) 3 P; it occurs in the form of plates, and usually surrounding all 
 nodules of troilite. 
 
 Pallasites which most nearly resemble iron meteorites, consist 
 of a sponge-like mass of nickel-iron, the pores of which are filled 
 with chrysolite. The proportion of metal to silicate varies in 
 different falls and in individuals of the same fall. A structure 
 peculiar to about 90% of all stone meteorites consists of rounded 
 grains or spherules. These are named chondri (sing., chondrus); 
 or if very minute, chondrules. Meteorites largely made up of 
 these are known as chondrites; if not, achondrites. In structure 
 chondri may themselves be granular, porphyritic or coarsely or 
 finely fibrous. They may consist of a single crystal individual 
 (monosomatic), or of several individuals (polysomatic) (Farring- 
 ton). During their passage through the atmospheric envelope 
 surrounding the earth, meteorites become highly heated, and if 
 metallic, a certain amount of oxidation occurs, part of the mate- 
 rial being lost in transit, and what remains forming a crust or 
 coating. The term iron glass has been suggested by Reichenbach 
 for the fused oxidized coating sometimes found on iron meteorites. 
 Under the microscope, in section, the crust of most iron meteorites 
 presents three and sometimes four well-marked zones. The outer- 
 most, called the fusion zone, is thin as compared with the 
 others; it is glassy, black, and opaque to brown and transparent. 
 Beneath this lies a broader transparent zone in which the constitu- 
 ents 01 the meteorites appear little if any changed, called by 
 Tschermak the absorption zone. The next and last is a broad 
 zone of black, opaque, spotted appearance. It may be so broad 
 as to make up four-fifths of the width of the crust; the constitu- 
 ents of the meteorite appear in normal condition, but impregnated 
 
METEORITICS MIDDLETON AND HAYWARD 293 
 
 with black, generally opaque matter, and is called by Tschermak 
 the impregnation zone (Farrington). 
 
 The surface furrows or pits in meteorites are termed piezoglyps. 
 
 Meteoritics. See page 291. 
 
 Metric Scale. See page 204. 
 
 Metric Ton. See Ton. 
 
 Meyer Process. See Recarburization. 
 
 Micaceous Hematite : Iron Ore. See page 244. 
 
 Micro (abbrev.). Microscopic, etc. 
 
 Microcellular Structure. See page 126. 
 
 Microcharacter. See page 284. 
 
 Microchemistry. See page 82. 
 
 Microcryptocrystalline. See page 126. 
 
 Microcrystalline (-crystallitic). See page 126. 
 
 Microcrystallography. See page 126. 
 
 Micro -flaws. Due to slipping: see page 283. 
 
 Micro-ghost; ghost Line. See page 289. 
 
 Microgram. See page 284. 
 
 Microgranitoid. See page 126. 
 
 Microgranular; Granulitic. See page 126. 
 
 Micrograph. See page 284. 
 
 Micrography. See page 284. 
 
 Microlite. See page 122. 
 
 Micrology. See page 284. 
 
 Micromeritic. See page 126. 
 
 Micrometallograph. See page 285. 
 
 Micrometallography. See page 263. 
 
 Micrometallurgy. See page 284. 
 
 Micrometer Caliper: Gage. See page 187. 
 
 Micrometry. See page 284. 
 
 Microphotogram : Photograph. See page 284. 
 
 Microporphyritic. See page 126. 
 
 Microradiometer. See page 205. 
 
 Microsclerometer. See page 480. 
 
 Microscope. See page 285. 
 
 Microscopic Analysis. See page 284. 
 
 Microscopic Constituents. See page 264. 
 
 Microscopic Etching. See page 286. 
 
 Microscopic Metallography. See page 263. 
 
 Microscopic Segregation. See page 213. 
 
 Microscopic Strain. See page 280. 
 
 Microscopic Structure. Or microstructure: see page 284. 
 
 Microscopically Cellular; Crystalline. See page 127. 
 
 Microscopy. See page 284. 
 
 Microspherulitic. See page 126. 
 
 Microstructure. See pages 284 and 289. 
 
 Microstructure Etching. See page 286. 
 
 Microtechnique. See page 284. 
 
 Microtome. An instrument for mounting specimens for micro- 
 scopic examination. 
 
 Middlesboro Pig Iron. See page 349. 
 
 Middleton and Hayward Furnace. See page 380. 
 
294 MIDDLETON PROCESS MIXER 
 
 Middleton Process. See page 502. 
 
 Middlings. See page 432. 
 
 Migratory Elements. See page 70. 
 
 Mil. See page 187. 
 
 Mild Cement. See page 67. 
 
 Mild Centered Steel. Steel cast with the center of softer material 
 than the outside : see page 64. This term might also be applied 
 to steel which has had the outside carburized by cementing or 
 casehardening. 
 
 Mild Ferro-Chrome. See page 352. 
 
 Mild Steel. See page 455- 
 
 Mild Tempered. See page 231. 
 
 Miles Dry Blast Process. See page 31. 
 
 Mill. (i) The equipment of a rolling mill; (2) in general, a steel or 
 other plant. 
 
 Mill Bar (obs.). Muck bar as distinguished from finished wrought 
 iron or merchant bar: see page 377. 
 
 Mill Cinder. See Slag. 
 
 Mill Fix (Eng.). See page 376. 
 
 Mill Furnace. See page 377. 
 
 Mill Iron. Pig iron suitable for puddling or for the basic open 
 hearth process. 
 
 MU1 Scale. See Scale. 
 
 Mill Tap. See Slag. 
 
 Milliolithic Ore. See page 244. 
 
 Mine Pig. See page 350. 
 
 Mineral. Ore; a term used in mining. 
 
 Mineral Carbon Blacking. See page 298. 
 
 Mineral Wool. See Slag Wool. 
 
 Minor Calorie. See page 199. 
 
 Minor Shrinkage. See page 54. 
 
 Minus Gage. See page 186. 
 
 Mirror Iron. See page 355. 
 
 Mirror Telescope, Fery. See page 207. 
 
 Miscible. Capable of mixing. 
 
 Mispickel. See page 245. 
 
 Missing Carbon. See Carbon. 
 
 Mitis Castings; Process. Castings made of steel to which a little 
 aluminum has been added to render it quiet; originally made of 
 steel manufactured by the Mitis process: see page 113. 
 
 Mitscherlich's Law. See page 121. 
 
 Mixed Cement See page 67. 
 
 Mixed Crystals. See pages 270 and 275. 
 
 Mixed Gas. See page 362. 
 
 Mixed Process (rare). (i) Duplex or other combination steel 
 process: see page 317. 
 
 Mixer. Sometimes called Jones mixer, after the inventor, also 
 receiver or reservoir. It is a large vessel for holding molten 
 pig iron, with a capacity of about 75 to 300 tons, and resembles a 
 tilting open hearth furnace. It is built of steel or iron plates 
 lined with basic or acid material, and is usually heated with gas. 
 Working doors or paddling doors (Eng.) are provided so lime or 
 
MOBILE STATE MOLDING 
 
 295 
 
 scrap to be melted up may be thrown in, etc. The pig iron as it 
 comes from the blast furnace in ladles is poured in through a 
 trough, and the vessel is emptied by tipping it sufficiently. It 
 may have one or all of the following objects: 
 
 i. Simply to keep the iron molten until it is desired for use. 
 '2. To obtain iron of more uniform composition by mixing the 
 product of several blast furnaces. 
 
 3. To effect a certain amount of desulphurization. This re- 
 quires about an hour or more, and a manganese content of about 
 i % or over. 
 
 FIG. 42. Mixer. 
 
 Mobile State. See page 281. 
 
 Modern High Speed Tools. See page 446. 
 
 Module (obs.). Modulus. 
 
 Modulus. (i) Of compressibility or compresskm : see page 334; 
 (2) of cubic compressibility: see page 335; (3) of elasticity: see 
 page 334; (4) of elasticity for shear: see page 335; (5) of extensi- 
 bility: see page 335; (6) of flexibility: see page 335; (7) of longi- 
 tudinal extension: see page 335; (8) of resilience: see page 335; (9) 
 of rigidity: see page 335.; (10) of rupture: see page 477; (n) of 
 shear: see page 33 5; (12) of specific extension: see page 335; (13) 
 of stiffness: see page 335. 
 
 Moffat Furnace. See page 160. 
 
 Moh's Scale. Of hardness: see page 478. 
 
 Moisture. See Water. 
 
 Molar Solution; Volume; Weight. See page 83. 
 
 Mold; Molding. Molding (obs. melting cast iron in a cupola for 
 foundry work) is the art of preparing molds (also called matrices 
 
2 96 MOLDING 
 
 sing., matrix for special purposes), i.e., cavities in suitable 
 materials which are to be filled with molten metal for the produc- 
 tion of objects of the desired shape known as castings (q.v.}. The 
 reasons for casting instead of rolling or forging are (a) lower cost 
 in certain cases, (b} intricacy of shape, and (c) with cast iron, the 
 impossibility of forming it in any other way. Molds for castings 
 of cast iron or steel are commonly made of Cast iron (steel molds 
 have been used to a limited extent) or sand; the two first are prin- 
 cipally for steel ingots, while the last is for more complicated 
 pieces, and for very large or special-shaped ingots. Sand molds 
 must be made up new for each casting; iron molds can be used 
 repeatedly, and hence are frequently called permanent molds. 
 Cast iron (rarely steel) molds are made by casting in sand molds, 
 consequently the preparation of the latter need only be con- 
 sidered. Sand molds may be either green sand, dry sand, or 
 loam. Green sand is sand in its natural condition, containing 
 some clay, and brought to the proper degree of dampness (called 
 tempering) to make it adherent. Dry sand is sand which has 
 been heated until all the moisture has been expelled, and is mixed 
 with a little water and flour or other substance which will deposit 
 carbon on heating and bind- the sand together, the water serving 
 to make the sand plastic during molding; usually a little fresh 
 sand is also mixed in. Loam is a clay with a somewhat lower 
 percentage of alumina (see analyses at end of section). Munk 
 suggests restricting the meaning of steel molding sand to a highly 
 siliceous, refractory sand used in the steel foundry; steel cleaning 
 sand to what is suitable for cleaning, especially sand blasting; 
 steel sand or iron sand to fine grained sand used for the best 
 kind of cleaning, and of much better quality than the regular hard, 
 angular, cleaning sand. 
 
 Dry Sand and Green Sand Molding. The cavity in the mold is 
 formed by packing or ramming the sand around a pattern, usually 
 of wood, having the shape of the casting. Owing to the contrac- 
 tion which the metal undergoes in cooling, it is necessary to make 
 the cavity, and hence the pattern, slightly larger than the casting 
 is to be. To assist in laying out the work, a special rule (molders' 
 rule, contraction rule, pattern makers' rule, or shrinkage gage) is 
 used. This is marked off in feet and inches as usual, but really 
 measures slightly more than it indicates to provide for the neces- 
 sary contraction without the trouble of making a separate calcu- 
 lation for each dimension of the casting. Double shrink is the 
 extra allowance for contraction required in preparing a metal 
 pattern which is first made from a wooden pattern, and the final 
 casting from this. To permit of the removal (drawing or deliv- 
 ery) of the pattern without unduly tearing the sand surrounding 
 it, it must be provided with a slight taper (strip, draft, draught), 
 i.e.. it must be larger at the top than at the bottom. To assist 
 in its withdrawal, a hook is usually screwed into the top by means 
 of which it is gently pulled out, at the same time being rapped 
 with a hammer or piece of wood. Rapping in is where the flask 
 is first filled with sand, a small portion removed, and the pattern 
 then knocked in. A pattern is said to be under-cut when the 
 
MOLDING 
 
 297 
 
 bottom part is larger than the top (the opposite of being tapered), 
 which prevents its removal from the sand, and in this case 
 coring must generally be resorted to. The sand is held in a box 
 or frame of wood or metal called the flask, molding box, or cast- 
 ing box. Depending upon the nature and the size of the casting, 
 the flask is divided into two or more parts; the top is called the 
 cope or case, the bottom the drag, bottom part, or nowel (Eng.), 
 and any intermediate parts, cheeks. The various parts of the 
 
 Oope 
 
 Oheek 
 
 Cheek 
 
 Drag 
 
 FIG. 43. Section of flask and pattern. 
 
 flask usually consist of sides without any top or bottom, and while 
 they are being nlled boards or bottom plates are clamped on to 
 prevent the sand from falling out until it is rammed into a com- 
 pact mass. 
 
 If the casting is small and perfectly simple, it may be possible 
 to have the pattern in one piece, but ordinarily it is necessary to 
 divide it into two or more parts to facilitate its removal from 
 the sand. In ramming up the mold, the bottom part of the pat- 
 tern is laid with the joint side down on a board (bottom board, 
 joint board, or odd side board), the bottom part of the flask is 
 
298 MOLDING 
 
 inverted over it, and sand is thrown in and rammed around the 
 pattern until the flask is full. A- board is now laid on top, the 
 whole turned right side up, and the bottom board (which is now 
 on top) removed, exposing the joint side of the pattern flush with 
 the sand. The other part of the pattern is now accurately fitted 
 to this by means of pegs in one part fitting into holes in the other. 
 Over the surface of the sand in the drag a little fine dry sand 
 (parting sand) or powdered charcoal is sifted to enable the two 
 parts of the mold to be separated later. The top (or next) 
 section of the flask is then put on, and sand thrown in and rammed 
 up as before. When full, a board is fastened on top, and the 
 cope lifted up and turned over. The two parts of the pattern are 
 now removed, the surface of the sand smoothed up and repaired, 
 and the mold finally fitted together again ready for pouring. 
 With green sand molds this may take place immediately. To 
 get the sand in the best condition, the surface is sometimes 
 brushed or wiped (swabbed) with water (held in the water pot or 
 swab pot) by a brush or swab. The parts of the mold are 
 clamped together, or heavy weights placed on top, to prevent 
 floating, i.e., separation from the pressure of the metal within, 
 which is of much greater specific gravity. In the case of dry 
 sand molds, after they are thus prepared they must be dried, i.e., 
 placed in a furnace called a drying oven or drying stove, and kept 
 for some hours at a temperature sufficient to expel all the mois- 
 ture; if too high it. causes burning, when the sand does not adhere 
 properly, and if it is used again the particles split up and become 
 so fine that they close up the pores in the mold. In cases where 
 it is not possible or convenient to put the mold in an oven, a port- 
 able coke fire or devil (Eng.) is sometimes set on top of the sand 
 to effect a more or less superficial drying. Better to protect the 
 surface of the mold from being worn away (washed or washed up) 
 by the flow of molten metal, it is often coated with facing sand, 
 which is made up of new sand mixed with various substances to 
 make it very firm and smooth. Blacking, consisting of powdered 
 charcoal, mineral carbon (coke), plumbago (blacklead or graph- 
 ite), so-called patent blacking (nearly pure carbon obtained by 
 the distillation of paraffin oil), etc., is sifted dry (dry blacking) 
 on the surface of the mold by means of a porous bag (blacking 
 bag), to give it a smooth finish and protect it from the washing 
 action of the metal; if mixed with water it is called wet blacking, 
 liquid blacking, or black wash coating, and is applied with a 
 brush, called a wet brush to distinguish it from the dry brush used 
 to dust loose sand from the cracks in molds. Green sand molds 
 are sometimes skin dried by applying some combustible liquid, 
 such as kerosene, and igniting it. 
 
 As the metal during solidification and also the mold always 
 evolve a quantity of gas, the walls of the mold must be porous to 
 permit it to escape, as otherwise the casting would be injured, at 
 least in appearance. The sand is kept more or less open and fire 
 holes are also punched with a wire (vent wire), these holes being 
 termed vent holes, and the operation venting or ventilation. 
 
 If the molten metal is poured directly into the top of the mold, 
 
MOLDING 299 
 
 it is called top pouring, and the mold is said to be an open top 
 mold; this is the usual method for casting ingots. With sand 
 molds, however, this would be apt to tear the surface, and there- 
 fore the metal is introduced through a pipe or tubular opening at 
 one side called a runner, feeder, git, guit, gate, ingate, inset 
 sprue, tedge, or pouring gate which connects with the bottom of 
 the mold proper by an opening known as a gate or feeding gate. 
 At the top of the runner is an enlarged depression (pouring basin) 
 to receive the metal from the ladle and insure its entering the 
 runner properly. This method is termed bottom pouring and the 
 mold a close top mold. This latter does not mean that it is 
 completely closed over, as there is usually an extension on top of 
 the mold proper called the sinkhead, lost head, or riser, and con- 
 nected with it by the rising gate or flow gate, and used for the 
 purpose of applying metal to fill up any pipe or cavity resulting 
 from the contraction of the metal in the casting; the top of the 
 riser is open and serves to show whether enough metal has been 
 poured into the mold. If the top surface of a casting is not 
 enclosed in the mold, it is termed an open sand mold. If a 
 number of molds are filled simultaneously from one central mold 
 (group casting), the latter, into which the metal is poured directly, 
 is known as a git mold (Eng.). 
 
 Coring. Holes or deep recesses in castings are formed by 
 inserting cylinders or pieces, usually made of hard baked sand 
 or clay, called cores, after the pattern has been removed from 
 the mold. A cod (Eng.) is a core of green sand. On the pattern 
 are slight projections forming holes or core prints in the walls of 
 the mold into which the cores are set. The cores are prevented 
 from shifting their position (floating) by metallic pieces, called 
 chaplets or studs, which are fastened against them in the sand. 
 For small sizes special nails with flat heads, called chaplet nails, 
 molders' nails, or core nails, are used, which are sometimes sup- 
 ported by a block of wood (chaplet block) previously driven into 
 the sand. Particularly for heavy cores a piece of iron, called an 
 anchor bolt, may be set inside the core and run through the core 
 print to the outside of the mold to which it is fastened. Where 
 more than one core is used, the main one is called the body core, 
 the others the branch cores. Where the core is of larger diame- 
 ter in the middle than at the ends, it is termed a chambered core, 
 belly (bellied) core, or roach belly core. With cores of large 
 diameter an iron bar (core bar) is put through the middle to stiffen 
 them. A plate used to support a number of such bars in the same 
 core is -called a core plate. When the bars must be very large 
 they are made hollow with perforations for venting, and are 
 termed core barrels. To prevent the interior or very large cast- 
 ings cooling so much more slowly than the exterior, a "pipe is 
 sometimes inserted through which a stream of water flows; this 
 arrangement is known as a water core. When considerable 
 pressure and washing action from the metal must be.resisted, the 
 cores may be cut out of solid carbon (carbon core) In making 
 cast-iron pipes the core barrel is usually wound with hay rope or 
 hay band underneath the sand covering, which chars away and 
 
300 MOLDING 
 
 so gives room for the contraction of the pipe. Cores are usually 
 prepared in wooden molds (core boxes), after which they are dried. 
 The sand, etc., of which they are composed is held together 
 by a core binder or core gum consisting of potato starch, 
 flour, etc., mixed with a little water. If a core is made in two 
 or more separate sections these are fastened (pasted) together with 
 clay water (water thickened with clay), etc. A metal box in 
 which cores are dried is called a sagger, saggar, or seggar. 
 
 If portions of the sand in a mold are poorly supported, nails or 
 brads (sprigs : Eng.) may be thrust through the solid part, and 
 this operation would be termed sprigging or nailing (Eng.). The 
 runners are sometimes called sprues, but this term is generally 
 restricted to the metal which solidifies in them and which must 
 be broken off the casting and remelted. To prevent the thick 
 and the thin portions of irregular -shaped castings from tearing 
 apart during cooling due to the thin portions solidifying first and 
 contracting, while the heavier portions are still molten or mushy, 
 they are connected or tied together by bent bars or brackets 
 (dogs) set in the molds before pouring. 
 
 Where it is desired to hasten the cooling of certain parts of a 
 casting, (a) to make the rate of contraction uniform throughout, 
 or (ft) with cast iron, to make the surface hard by retaining most 
 of the carbon in the combined condition, pieces of iron (chills) are 
 inserted in the mold flush with the surface. In the case of cast- 
 iron car wheels, where it is desired to have the tread hard, a device 
 known as a contracting chill is employed; this is arranged with 
 metal segments mounted on an iron ring, the segments expanding 
 inward from the heat from the casting, and remaining in contact 
 with it as it cools and contracts. An iron mold for ingots might 
 be termed a chill mold, but this name is usually restricted to a 
 mold used for cast iron, and not for steel. Plate molding, used 
 principally for small castings, consists in first casting a metallic 
 pattern on a metal plate to insure ease and accuracy of handling. 
 The pattern may be divided between two plates, provided with 
 the necessary gates, etc. A plate may also be used having a hole 
 exactly fitting the pattern, through which the pattern is with- 
 drawn after ramming, the pattern projecting a little way above 
 the plate (stripping plate). Reversed molds or ramming blocks 
 are plaster or metal molds used in some classes of repetition mold- 
 ing work. The actual casting molds are made from these blocks 
 direct, instead of from a pattern, and the advantage of their 
 employment is that a very large number of molds can be made 
 precisely alike without the labor of forming the parting surfaces 
 and runners and risers at every molding (Horner). Multiple 
 molding is where a number of molds are piled one on top of the 
 other and connected with a common runner by which they are 
 filled. 
 
 Loam Molding or Sweep Molding. This method is used for 
 producing objects having surfaces of rotation, i.e., symmetrical 
 circular sections. Objects such as large gears, round bottomed 
 pots or kettles, blast furnace bells, etc., can be molded very 
 quickly and economically by this method. Loam (a sand rich in 
 
MOLDING 301 
 
 clay) or green sand is employed. The mold or case is first built 
 up with bricks. These are held together and given a first coating 
 with roughing loam or black loam, of cheap quality and strong 
 binding properties. A finer grade is then used. A templet or 
 arm called a sweep is fastened to and turned around a bar as an 
 axis, which is set in the center of the brickwork. The lower edge 
 or surface of the sweep has the shape which it is desired to impart 
 to the mold, which it imparts as it is turned around. The drag 
 and the cope are similarly formed, except the former is concave 
 while the latter is convex, with a space left between the two (when 
 put together) corresponding to the thickness desired in the cast- 
 ing. With gear wheels, the space between the teeth is cored out 
 by hand or by a machine. The sweep is also called a strickle 
 (Eng.), and the method of molding, strickling, striking up, or 
 sweeping up. 
 
 The cire perdu process (lost wax process, waste wax process) 
 is generally used for small bronze work of an artistic nature. A 
 rough sand pattern of the object is first made, which is as much 
 smaller than the object as the thickness desired for the metal in 
 the casting, and is then coated with wax to the desired size, and 
 the details finished by the artist. The whole is placed in sand in 
 the same manner as an ordinary pattern, and is heated so the wax 
 will melt and run out. The sand core remaining is held in place 
 by wires run through it, and the space thus left is filled with 
 metal. 
 
 Machine Molding. In many cases where a number of castings 
 are to be made from the same pattern it has been found advanta- 
 geous to employ a machine which quickens the operation of mold- 
 ing, and also does away with much of the skill and labor required 
 when it is done by hand as already described. The machine may 
 be a squeezer, in which a squeezer board, operated by a lever, 
 presses the sand around the pattern in the flask, or the pressing 
 may be done by compressed air (pneumatic molding machine). 
 The removal of the pattern may still be done by hand, or better, 
 by a special type of machine which forces it either up or down 
 through a stripping plate. In the vibrator machine the pattern is 
 removed by vibrating it very rapidly an extremely small amount 
 back and forth, so the sand in the mold is not disturbed appreci- 
 ably, and no stripping plate is necessary. In the jar machine 
 which is coming into extensive use, the flat platform or platen 
 forming the top of the machine is raised from 2 to 5", and allowed 
 to drop at intervals of i to 5 seconds, depending upon the size of 
 the machine and of the flask to be rammed. The flask with the 
 pattern in place, and filled with loose sand, is placed on the 
 machine, and this jarring properly rams the mold. 
 
 Floor sand is that already used and emptied from dry sand 
 flasks and swept up from the floor. A screen used for sifting sand 
 by shaking, operated by machine or by hand, is termed a riddle, 
 
 Following are sample analyses of clay, sand^and loam: 
 
German clay. . . 
 White clay 
 Black clay 
 
 . 78 
 . 68 
 61 
 
 39 
 .90 
 
 .76 
 
 i. 
 o. 
 
 2 
 
 23 
 60 
 20 
 
 13 
 
 21 
 24 
 
 .83 
 . 2O 
 .40 
 
 o 
 o 
 o 
 
 .80 
 .25 
 
 .40 
 
 0.81 
 0.90 
 0.92 
 
 Green sand 
 Dunbar sand . . 
 Coxey sand 
 
 . 86 
 . 98 
 . 96 
 
 64 
 .46 
 .05 
 
 O 
 
 3 
 o, 
 o, 
 
 13 
 44 
 ,40 
 
 6 
 o 
 
 2 
 
 99 
 67 
 .80 
 
 
 
 .43 
 
 0.07 
 
 Loam 
 
 . 76 
 
 .06 
 
 3 
 
 64 
 
 II 
 
 .66 
 
 o 
 
 .28 
 
 1.42 
 
 302 MOLD GASES MONOTRIMETRIC SYSTEM 
 
 SiO 2 Fe 2 O 3 A1 2 3 CaO MgO Loss 
 
 4-74 
 7-50 
 8.60 
 2.81 
 0.36 
 
 o-75 
 6.20 
 
 Mold Gases (Howe). Those evolved from molten and solidifying 
 iron at atmospheric pressure. 
 
 Molders' Nail. See page 299. 
 
 Molders' Rule. See page 296. 
 
 Molding Box. See page 297. 
 
 Mole. See page 83. 
 
 Molecular Ease. The condition in which the molecules in a body 
 are allowed to take their normal or natural position. 
 
 Molecular Friction. See page 268. 
 
 Molecular Heat. See page 201. 
 
 Molecular Inertia. See page 264. 
 
 Molecular Motion. See page 199. 
 
 Molecule. See page 81. 
 
 Moler. See page 396. 
 
 Molten. See pages 267 and 269. 
 
 Molten Metal. Pig iron in the molten or fluid condition. 
 
 Molybdenum. Mo; at. wt, 96; sp. gr., 8.6. It is never found un- 
 combined. The pure metal is white and is merely a chemical 
 curiosity. It is obtained as an alloy with iron called f erro-molyb- 
 denum (see page 353), and is used to a certain extent in the 
 manufacture of special steels (see page 450). This name was 
 formerly a synonym for plumbago. 
 
 Molybdenum Hardenite. See page 275. -. 
 
 Molybdenum Steels. See page 450. 
 
 Monad. See page 86. 
 
 Monatomic. See page 87. 
 
 Monell Process. See page 316. 
 
 Monkey. (i) In a blast furnace: see page 32; (2) in the manufac- 
 ture of steel, the rods, called respectively long and short-tailed 
 monkeys, placed in the cinder pit, and forming a frame to hold the 
 slag together and allow it to be taken out with a crane; (3) a 
 dolly; (4) a tup. 
 
 Monnot Process. See page 372. 
 
 Monobasic. See page 87. 
 
 Monocellular Structure. See page 1 26. 
 
 Monoclinic System. Of crystallization: see page 120. 
 
 MonocUnohedral System. Of crystallization: see page 120. 
 
 Monodimetric System. Of crystallization: see page 120. 
 
 Monometric System. Of crystallization: see page 120. 
 
 Monomorphic. See page 121. 
 
 Mono somatic. >ee page 292. 
 
 Monosymmetric System. Of crystallization: see page 120. 
 
 Monotrimetric System. Of crystallization: see page 120. 
 
MONOVALENT MYNE 303 
 
 Monovalent. See page 86. 
 
 Monovariant System. See page 327. 
 
 Monotropic Transformation. See page 327. 
 
 Mop. See page 115.* 
 
 Morf Process. See page 373. 
 
 Morgan Mill. See pages 412 and 416. 
 
 Morphology. See page 121. 
 
 Morphometry. See page 121. 
 
 Morse Optical Pyrometer; Thermogage. See pageboy. 
 
 Mother Liquor. See page 266. 
 
 Mother Metal. See pages 56 and 266. 
 
 Mother -of -Pearlyte (obs.). An old name suggested by Howe for the 
 
 constitution of iron from which pearlite is formed on further 
 
 cooling. 
 
 Motherless Pigs. See page 342. 
 Motion Plane. See pages 123 and 282. 
 Mottle. See page 433- 
 Mottled Iron; Pig. See pages 342 and 346. 
 Mould, etc. Mold, etc. 
 Mound. See page 181. 
 Mouth. The top or aperture of a blast furnace, Bessemer converter, 
 
 etc. 
 
 Movable Bottom, Holley. See page 17. 
 Moving Load; Concentrated Load. See page 468. 
 Muck Bar. See page 377. 
 Muck Mill; Train. See page 413. 
 Muffle; Muffle Furnace. See page 183. 
 Multicellular Structure. See page 126. 
 Multiple Casting. See page 61. 
 Multiple Drawing. See page 508. 
 Multiple Isomorphism. See page 121. 
 Multiple Molding. See page 300. 
 Multiple Proportions. Law of: see page 85. 
 Multiple Teeming; Pouring. See page 61. 
 Multiple Twinning. See page 124. 
 Mundic. See page 245. 
 Munton Process. See page 60. 
 Murdock Converter. See page 24. 
 Muriatic Acid. Commercial hydrochloric acid. 
 Mushet (D.) Process. (i) Direct process: see page 144; (2) for 
 
 deoxidizing by manganese additions: see page 393. 
 Mushet (R.) Process. Of desiccation: see page 30. 
 Mushet Steel. See page 445. 
 Mushy. See page 55. 
 Mushy Stage. See page 268. 
 Mushy Structure. See page 125. 
 Muzzle. The nozzle or end of a tuyere. 
 Myne (obs.). Mine (Eng.) or ore. 
 
N. (i) Chemical symbol for nitrogen, q.v.; (2) normal, of a solu- 
 tion: see page 83. 
 
 Na. Chemical symbol for sodium (Latin, natrium), q.v. 
 
 Nb. Chemical symbol for niobium (usually called columbium) : 
 see page 84. 
 
 Nd. Chemical symbol for neodymium: see page 84. 
 
 Ne. Chemical symbol for neon: see page 84. 
 
 Ni. Chemical symbol for nickel, q.v. 
 
 Nt. Chemical symbol for niton: see page 84. 
 
 No. 2 Iron; No. 3 Iron. See page 378. 
 
 N. M. T. A. National Metal Trades Association. 
 
 Nailing. See page 300. 
 
 Narrow Twin. See page 125. 
 
 Nascent. See page 87. 
 
 Nasmyth Process. See page 380. 
 
 Nathusius Furnace. See page 162. 
 
 Native Bloomary; Forge Process. See page 144. 
 
 Natural Condition; State. Of metal, simply cooled after the last 
 mechanical (ordinary) treatment. 
 
 Natural Corrosion. See page 108. 
 
 Natural Gas. A highly combustible gas occurring in pockets or 
 caverns in the earth. In districts near which it occurs it is largely 
 used for metallurgical purposes on account of its high calorific 
 power and low sulphur. It consists almost entirely of marsh gas 
 (methane) and hydrogen, the following being a representative 
 analysis_by volume: 
 
 Hydrogen 20 % 
 
 Methane 70 
 
 Other hydrocarbons 6 
 
 Carbon dioxide i 
 
 Nitrogen 3 
 
 Natural Hardness. See Hardness. 
 
 Natural Steel. (i) Old name for "steel" made direct from ore; (2) 
 
 tool steel: see page 446. 
 Nature. Come to nature: see page 376. 
 Nature Prints. See page 288. 
 Nau Process. (i) Casting process: see page 61; (2) purification 
 
 process: see page 387. 
 Nealing (obs.). Annealing. 
 Neck. Of a roll: see page 403. 
 Necking. Of a test piece: see page 336. 
 Needle Fracture. See page 178. 
 Needle-shaped Crystal. See page 126. 
 Negative Crystal. See page 127. 
 Negative Hardening: Quenching. See page 231. 
 Negative Segregation. See page 56. 
 Nerve Structure. See page 125. 
 
 34 
 
NESH NITROGEN 305 
 
 Nesh (Eng.). Tender or brittle, as of tin plates. 
 
 Nested. Of crucibles: see page 112. 
 
 Net Structure. See page 126. 
 
 Net Ton. See Ton. 
 
 Network Size; Structure. See page 126. 
 
 Neuberg Process. See page 63. 
 
 Neumann Bands ; Lamellae ; Lines; Structure. See pages 127 and 
 292. 
 
 Neutral. (i) Of oxidized materials, neither acid nor basic; (2) of a 
 flame, neither oxidizing nor reducing; (3) of wrought iron, neither 
 red-short nor cold-short (rare). 
 
 Neutral Axis. See page 337. 
 
 Neutral Coke. See page 97. 
 
 Neutral Lining. See Lining. 
 
 Neutral Moment. In solidifying: see page 54. 
 
 Neutral Refractories. See page 398. 
 
 Neutral Siemens Process. See page 310. 
 
 Neutral Surface. See page 337. 
 
 Neutralizing. Of phosphorus: see page 385. 
 
 Neville Process. See page 144. 
 
 New Tool Steel. See page 446. 
 
 Newland's Law of Octaves. See page 85. 
 
 Newton's Law of Cooling; Radiation. See page 200. 
 
 Newton Process. (i) Cementation process: see page 73; (2) 
 crucible process: see page 118; (3) direct process: see page 144. 
 
 Nichrome. The trade name for an alloy containing approximately 
 nickel 60%, chromium 14%, with the remainder chiefly iron. It 
 is largely used for parts exposed to high temperatures owing to its 
 comparative freedom from oxidation and change of form. 
 
 Nick Bend Test. See page 476. 
 
 Nick and Break Test. For rails; see page 483. 
 
 Nickel. (i) Influence on corrosion: see page 366; (2) commercial 
 nickel: see page 353. 
 
 Nickel. Ni; at. wt., 58.5; melt, pt., 1435 c - ( 26l 5 F.); sp. gr., 
 8.6 to 8.93. It is not found in the free state, but usually com- 
 bined with sulphur or oxygen. It is a lustrous white metal with a 
 slight yellow tinge when compared with silver. It is hard, strong, 
 ductile, and malleable. It is obtained in the metallic condition 
 (nearly pure) or as an alloy with iron, called ferro-nickel (see 
 Page 353), and is used in the manufacture of nickel steel (see 
 page 450). 
 
 Nickel-Chrome Steels. See page 451. 
 
 Nickel-Ferrite. See page 272. 
 
 Nickel Plating. See page 371. 
 
 Nickel Steel. See page 450. 
 
 Nickel Steel Armor Plate. See page 8. 
 
 Nipper. See page 508. 
 
 Nitric Acid. For etching: see page 287. 
 
 Nitro-Cyanide of Titanium. See Salamander. 
 
 Nitrogen. N; at. wt., 14; melt. pt.,-2i3 C. ( 351 F.); boil, pt., 
 -195-5 C. (-319-9 F -); sp. gr., 0.973 (air = i); i liter weighs 
 1.250 grams. It is a colorless, odorless, and tasteless gas, and its 
 20 
 
306 NOBBIN NORMAL 
 
 principal occurrence is in air, of which it constitutes about four- 
 fifths by volume, mechanically mixed with oxygen. It combines 
 directly with very few of the elements, and separates readily from 
 many of its compounds, often with explosive violence. It is 
 found in iron, apparently forming a feeble compound, which 
 tends to make the metal brittle; it is removed by the action of 
 titanium or vanadium. 
 
 Nobbin (rare). A bloom of puddled iron worked under the ham- 
 mer. 
 
 Nobbing. See Forging. 
 
 Nobili's Thermopile. See page 207. 
 
 Noble Furnace. See page 162. 
 
 Noble Metal. See page 84. 
 
 Noble Metal Couple. See page 209. 
 
 Nodulizing. See page 45. 
 
 Non-acicular Martensite. See page 276. 
 
 Non-anodic Passivity; Polarization. See page 364. 
 
 Non-Bessemer Ore. See page 243. 
 
 Non-caking Coal. See Coal. 
 
 Non-coking Coal. See Coal. 
 
 Non-continuous Combustion. See page 202. 
 
 Non-corro Steel. See page 451-. 
 
 Non-crystalline. See page 119. 
 
 Non-crystalline Movement. See page 281. 
 
 Non-eutectic Cementite. See page 273. 
 
 Non-eutectoid Cementite. See page 273. 
 
 Non-eutectoid Ferrite. See page 272. 
 
 Non-ferrous Alloy. See Alloy. 
 
 Non-ferrous Structure. Differing from that of ordinary (plain 
 carbon) ferrous metals; as of alloy steels or cast irons. 
 
 Non-homogeneous System. See page 328. 
 
 Non-magnetic Steels. See page 445. 
 
 Non-malleable. Of metals, not capable of being worked to a useful 
 degree. 
 
 Non-metal ; Non-metallic. See page 83. 
 
 Non-phosphoric Pig. See page 344. 
 
 Non-refractory Clays. See page 396. 
 
 Non-reversible. Of alloys, processes and transformations: see 
 pages 265 and 327. 
 
 Non-reversing Mill. See page 408. 
 
 Non-variant System. See page 327. 
 
 Non-Walloon Processes. See page 75. 
 
 Noodle. See page 17. 
 
 Nordman's Heterochrome Photometer. See page 208. 
 
 Noric Iron. An iron formerly manufactured in what are now 
 Styria and Carinthia; it is mentioned by various classical writers. 
 
 Normal. (i) Of material which has been finished in the usual 
 manner in contradistinction to that which has received special 
 treatment; (2) in connection with the phase rule: see page 
 326; (3 perpendicular; at right angles; (4) of illumination^ for 
 microscopic work; vertical; (5) regular or standard; (6) average 
 or mean, as normal temperature. 
 
NORMAL CARBIDE NYHAMMER BLOOMARY 307 
 
 Normal Carbide. See page 272. 
 
 Normal Pearlite. See page 273. 
 
 Normal Scale. Of temperatures: see page 205. 
 
 Normal Solution. See page 83. 
 
 Normal Steel (rare). Plain carbon steel. 
 
 Normal Stress. See page 332. 
 
 Normal System. See page 326. 
 
 Normal Thermometer. See page 205. 
 
 Normalizing. See page 232. 
 
 Norris Wear Test. See page 480. 
 
 Northrup's Ratiometer. See page 208. 
 
 Norton Process. See page 65. 
 
 Nose. (i) The top section of a Bessemer converter: see page 17; 
 (2) the lip of a ladle; (3) the blunt end of a die or hammer; (4) an 
 accumulation of chilled material around the inner end of a 
 tuyere in a smelting shaft furnace, protecting and prolonging the 
 tuyere (Raymond). 
 
 Nose Helve. See Hammer. 
 
 Notch Gun. For a blast furnace: see page 37. 
 
 Notch Toughness. See page 482. 
 
 Nowel. See page 297. 
 
 Nozzle. See Ladle. 
 
 Nucleus. Core; see page 67. 
 
 Number. In wire drawing: see page 509. 
 
 Nut Coal. See Coal. 
 
 Nyhammer Continuous High Bloomary. See page 144. 
 
o 
 
 O Chemical symbol for oxygen, q.v. 
 s ' Chemical symbol for osmium: see page 84 
 O. D. Outside diameter. 
 O. H. Open hearth. 
 Oar (obs.). Ore. 
 
 Obersteiner Process. See page 118. 
 Objective. Of a microscope: see page 285. 
 Oblique Fracture. See page 179. 
 Oblique Illumination. See page 285 
 Oblique Stress. See page 332. 
 Oblique System. Of crystallization: see page 120 
 Obstruction Theory. See page 341. 
 Obstructive Elements. See page 276. 
 
 Occlusion. The property possessed by certain metals, such as 
 iron, platinum, and notably palladium, of absorbing large 
 quantities of a gas when heated, and retaining it when cold 
 (Newth); see also page 328. 
 Ochre. See page 244. 
 Octahedral Cleavage. See page 124. 
 Octahedrite. See page 291. 
 Octaves, Law of. See page 85. 
 Odd-side Board. See page 297. 
 Off. (i) To be through operating, or not operating; (2) to have 
 
 the wrong composition, e.g., to be off in carbon. 
 Off the Boil. See page 314. 
 Off Iron. Pig iron of a different grade from that intended to be 
 
 made. 
 
 Oil Cooling. See page 227. 
 Oil Finish. See page 433. 
 Oil Flaring. See page 231. 
 Oil Furnace. See page 181. 
 
 Oil Gas. This is obtained by the splitting up of a hydrocarbon 
 oil at a high temperature, with or without the use of air or 
 steam, into a permanent gas. It is used almost exclusively for 
 lighting as its cost of production is too great for metallurgical 
 purposes. Water oil gas (devised by Archer) is made as follows : 
 Steam superheated to about 1000 F. (550 C.) is made to pass 
 through an injector and draw with it a quantity of oil which 
 becomes mixed with the steam. The mixture is further heated 
 to about 1300 F. (700 C.), when it receives an additional quan- 
 tity of oil; and finally the mixture is heated to 2400 F. (1300 C ) 
 whereby it is converted into permanent gas." Pintsch gas 
 among others, is made by dropping oil into a red-hot retort' 
 somewhat on the principle of a "flash" boiler, which splits it up 
 into a permanent gas. Air gas is the combustible mixture of air 
 and hydrocarbons obtained when ordinary air is passed through 
 the more volatile (liquid) constituents of petroleum. The 
 
OIL GAS PRODUCER OPEN HEARTH PROCESS 309 
 
 Amet-Ensign oil gas producer is used in California where the 
 oil has an asphalt base, so it is generally used only under steam 
 boilers. The oil is fed in from a weir box provided with an 
 adjustable needle .valve and runs down an adjacent inclined 
 slide or plate, while the air comes up from below and passes under 
 the lower edge. The products of combustion and distillation 
 there formed pass up through a brick-lined combining tube and 
 thence down to a water seal, after passing which they enter a 
 rotary washer. Steam is to be used in the more recent forms 
 (Iron Age, July 13, 1911). 
 
 Oil Gas Producer. See Oil Gas. 
 
 Oil Hardening; Quenching; Tempering. See pages 227 and 228. 
 
 Oil Toughening. See page 232. 
 
 Oil of Vitriol. Commercial sulphuric acid. 
 
 Oily Liquid. See page 121. 
 
 Old European Process. For malleable castings: see page 258. 
 
 Old High Bloomary. See page 147. 
 
 Ologist Ore. See page 244. 
 
 On. To be operating. 
 
 On the Boil. See page 314. 
 
 On Gas. See page 34. 
 
 On Wind. See page 34. 
 
 Onchnoid. See page 290. 
 
 Oncosimeter. See page 483. 
 
 One-blow Test. See page 482. 
 
 Onion (Onion Skin) Type. Of freezing: see page 55. 
 
 Onions Process. See page 118. 
 
 Oolitic Hematite ; Ore. See page 244. 
 
 Oolitic Structure. See page 125. 
 
 Open. Of the charge in a blast furnace: see page 35. 
 
 Open Annealing. See page 431. 
 
 Open Fire. See page 75. 
 
 Open Fore-part. See page 32. 
 
 Open Front. See page 32. 
 
 Open Grained Iron; Pig. Pig iron whose fracture shows large 
 grains or crystals. 
 
 Open Hearth. See pages 75 and 182. 
 
 Open Hearth Basic Pig. See page 343. 
 
 Open Hearth Furnace. See pages 183 and 310. 
 
 Open Hearth Process. A process for the production of steel by 
 the oxidation and removal of the impurities contained in a bath 
 of metallic iron lying on the hearth of a regenerative furnace 
 (see page 183), the -product being tapped in a fluid condition. 
 The charge may consist of (0) pig iron (either solid or molten) ; 
 (&) pig iron and scrap; or (c) scrap and carbon (coal or coke). 
 There are two modifications, depending upon the nature of the 
 lining of the furnace : 
 
 1. Acid open hearth process, with removal of silicon, man- 
 ganese, and carbon. 
 
 2. Basic open hearth process, with removal of silicon, manga- 
 nese, and carbon, as in the acid process, and in addition most of 
 the phosphorus and often some of the sulphur. 
 
3 1 o OPEN HEARTH PROCESS 
 
 The original method (acid) of C. W. Siemens was to melt 
 pig iron alone, and oxidize the impurities with ore (Siemens 
 process, pig and ore process), while the Brothers Martin added 
 scrap without ore to molten pig iron until the bath had the right 
 composition, there being only slight oxidation from the gases 
 (Siemens-Martin process, Martin-Siemens process, Martin 
 process, pig and scrap process), consequently the former was an 
 oxidation process while the latter was principally a dilution 
 process. These various names have, however, lost their signifi- 
 cance and are used interchangeably, the terms pig and ore or pig 
 and scrap being employed where it is necessary to distinguish 
 between them. Ordinarily a combination method employing 
 pig, scrap, and ore is practised. In this country the name 
 open hearth process is used on account of the type of furnace. 
 The name neutral Siemens process has been applied where only 
 pig and scrap (without any ore) are used. The terms ordinary 
 or straight open hearth process are employed to distinguish 
 regular practice from special methods or modifications as de- 
 scribed below. 
 
 Open Hearth Furnace. This is a regenerative reverberatory 
 furnace, the name being derived from the fact that the hearth 
 is open or exposed to the action of the flame. It should more 
 properly be termed a Siemens furnace or Siemens regenerative 
 
 FIG. 44. 6o-ton open hearth furnace. 
 
 furnace; the term Martin furnace (used on the Continent) 
 is incorrect as the Martins had nothing to do with the design 
 of the furnace only with the process. The furnace com- 
 prises a hearth or sole which contains the charge, covered with 
 an arched roof of bricks; ports or passages at each end, the air 
 and gas for combustion entering at one end and leaving at the 
 other; regenerators (regenerative chambers) at each end, 
 connected with the ports by vertical flues (uptakes), and lead- 
 ng to the chimney or stack; at the bottom of the uptakes are 
 
OPEN HEARTH PROCESS 
 
 small chambers or receptacles (cinder pockets, slag pockets, 
 or dirt pockets), easily cleaned, for the purpose of catching -any 
 particles of cinder or dirt carried over, so as to protect the 
 checkers. The hearth consists usually of metal plates lined 
 with silica bricks, on top of which is the lining proper, consist- 
 ing (a) for acid practice, of silica bricks covered with fine sand; 
 (b) for basic practice, of magnesite bricks covered with crushed 
 dolomite, sometimes mixed with a little pitch or tar. The roof 
 and walls above where the slag of the charge comes (slag line) 
 are built of silica (rarely magnesite) bricks, and below this of 
 silica (acid) or magnesite (basic) bricks, depending upon the 
 process. Sometimes chrome (neutral) bricks are inserted 
 
 FIG. 45. Model of a 50-ton open hearth furnace. 
 
 between silica and magnesite bricks. The hearth is provided at 
 the back with a tap hole which, in the case of stationary furnaces, 
 must be stopped up carefully with refractory material; with a 
 tilting furnace, except, when tapping, it is above the level of the 
 bath, and so need not be closed up tightly. The hearth is usually 
 rectangular in shape, rarely round or oval. The regenerators 
 are the distinctive feature of the furnace and consist of fire-brick 
 flues nearly filled with bricks set on edge and arranged so as to 
 leave a great number of small passages, known as checkers or 
 checker work, which abstract most of the heat from the out- 
 going waste gases and return it later to the incoming (cold) gases 
 
312 
 
 OPEN HEARTH PROCESS 
 
 for combustion. If producer gas is used, both the air and gas 
 are preheated in separate regenerators, uniting and burning only 
 when they enter the furnace; with natural gas or petroleum, 
 only the air is preheated. 
 
 Furnaces may be built either on a permanent foundation 
 (stationary or fixed furnace), or so arranged that the part com- 
 prising the hearth may be tipped (tilting, tipping, or rolling 
 furnace). The first type of furnace had vertical regenerators 
 (i.e., the greatest dimension was vertical), which necessitated 
 having the hearth and the charging floor considerably elevated 
 above the ground level; the present practice is to make the 
 regenerators horizontal, as this lowers the charging floor which 
 can then be on the ground level, and also offers certain other 
 
 It is now considered best to have 
 a 12"roof through-out 
 
 H ' " 
 
 Daubed with chrome cement - 
 
 2 Courses magnesia brick on edge/ Granite or concrete // Loam, fettling etc. N\ 
 
 1 Course chrome ., Th JS e checkers are.not i/the These checker brick 
 
 uptake, but in a chamber just rest on tile 8"x 12 'i 6" 
 
 beyond and opening into it 
 
 FIG. 46. Materials of construction and lining for basic open 
 hearth furnace. (Stoughton, Met. of Steel.) 
 
 advantages. One disadvantage of this latter arrangement is 
 that the pit at the back of the furnace which holds the ladle for 
 the steel, and the slag which runs over (cinder pit, slag pit, or 
 ladle pit) must be correspondingly deep, and therefore difficult 
 to clean on account of the heat. To overcome this difficulty, 
 the ground at the back of the furnace may be dug away, making 
 the cinder pit very shallow. This type of construction, is called 
 a double level furnace ; the old style, a single level furnace. 
 In the first furnaces the hearth was supported on the regen- 
 erator arches which were weakened by the high temperature 
 to which they were exposed; also any charge breaking through 
 the bottom would choke them up. This is avoided by the use 
 of horizontal regenerators which are not underneath the hearth ; 
 it was also avoided in a special type of furnace, called the Batho 
 furnace, in which the vertical regenerators were inclosed in an 
 
OPEN HEARTH PROCESS 313 
 
 iron sheathing, being set to one side and independent of the 
 furnace. This furnace had a round (sometimes an oval or 
 elliptical) hearth, and the roof was set in an iron frame so ar- 
 ranged that it could be lifted off to permit of charging scrap too 
 large to pass through the regular charging doors, originally 
 intended to facilitate repairs and relining. Such a furnace is 
 termed a removable top furnace (sometimes a round top furnace), 
 a few of which are still employed. 
 
 In this country furnaces used in connection with the manu- 
 facture of ingots generally have a capacity per charge of about 
 50 to 100 tons; for some special processes, up to 200 tons or 
 over, and in this case are usually tilting. Smaller furnaces, 
 about 10 to 20 tons in size, are generally confined to the manu- 
 facture of steel for castings. With ordinary practice, a heat 
 takes from about 6 to 12 hours, usually 8 to 10 hours, and a 
 furnace will make about 12 to 22 heats per week, depending upon 
 the size (less for large than for small). 
 
 FIG. 47. 6o-ton open hearth furnace, showing charging machine 
 and charging boxes. 
 
 With a newly built furnace, before it can be used for making 
 steel, the first operation is making bottom, i.e., putting in the 
 lining. Gas is burned to warm up the hearth and the checkers 
 until the full working temperature is reached. With proper 
 construction a sufficiently high temperature to fuse the roof 
 can be attained. The refractory lining is then put on in thin 
 layers, each of which is sintered in place before the next is put 
 on. With an acid furnace a certain amount of old slag is then 
 thrown in, melted, and tapped out. This is called a wash 
 heat or wash out heat and is for the purpose of making the 
 bottom dense and firm. The furnaces were originally charged 
 by hand, the materials being laid on a peel (a bar flattened out 
 at one end like a spade) which was rested on the sill of one of 
 the doors as a fulcrum, and so pushed in (peel charging); but 
 with modern large furnaces, both on account of the time required 
 
3 1 4 OPEN HEARTH PROCESS 
 
 and the arduousness of the labor, this is done by a machine 
 (charging machine). The stock is loaded into boxes (charging 
 boxes) which are picked up by the machine and dumped in the 
 furnace by revolving the peel of the machine which engages with 
 them at one end. 
 
 Acid Open Hearth Process. Ordinarily the charge is com- 
 posed of pig and scrap, the scrap as a rule constituting the greater 
 part. The materials must contain less phosphorus (0.06%) 
 than is to appear in the finished steel (see page 343). In some 
 cases the scrap is charged first, with the pig on top, in others 
 this order is reversed, the object being to prevent scorification of 
 the lining by the iron oxide formed during melting. The first 
 stage consists in melting the materials down, during which much 
 of the silicon, manganese, and carbon are oxidized. When 
 completely melted, the bath should contain about 0.60% of 
 carbon if low-carbon steel is to be made, or over i % for high- 
 carbon steel for springs, etc. To determine this, a sample is 
 taken out in a spoon and poured into a small mold, the test 
 ingot resulting being chilled in water and broken, its fracture 
 giving the desired information. Frequently with high-carbon 
 steel a quick chemical determination is also made. If the heat 
 melts high, i.e., if the carbon is still too high, ore in small amounts 
 can be fed in (oreing or oreing down) to effect the oxidation, 
 without danger of corroding the lining, as this is now protected 
 by the metallic bath and the slag already formed; if the heat 
 melts low, with the danger of the bath not getting hot enough by 
 the time the carbon is nearly all gone, pig is thrown in to supply 
 the deficiency in carbon, and this is termed pigging, pigging back, 
 or pigging up. The period after melting, when the carbon is 
 being oxidized, is sometimes called the boil, and the charge is said 
 to be on the boil ; if nearly all the carbon has been oxidized, it is 
 off the boil. To assist in oxidizing the carbon, the bath may be 
 stirred (shaken down) with an iron rod. In some cases steel may 
 be obtained with a higher percentage of silicon than usual, due to 
 a reaction or sand boil (Eng.) whereby silicon is reduced from the 
 bottom or banks of the furnace. 
 
 A certain amount of heat is generated by the oxidation of the 
 impurities, but the greater part is obtained from the combustion 
 of the gas. Contact of the iron with the hot gases is principally 
 brought about by the evolution of the carbon monoxide gas 
 formed by the oxidation of the carbon in the metallic bath, which 
 causes it to bubble and seethe; consequently it is necessary to 
 have a certain amount of carbon in the bath, as otherwise it will 
 be too cold to tap. The temperature of the bath is determined 
 partly by the eye and partly from the effect on a low-carbon iron 
 bar in about ten seconds. If the bar is melted off sharply the 
 bath is sufficiently hot, while if it tapers to a point it is too cold. 
 The direction of the air and the gas for combustion is reversed 
 at regular intervals: about 20 minutes at the beginning and 15 
 minutes or less toward the end of the heat. 
 
 Just before tapping, a small amount of ferro-manganese is 
 usually thrown into the furnace to hold the heat, i.e., to prevent 
 

 OPEN HEARTH PROCESS 3 1 5 
 
 any further removal of carbon, and also to effect a partial de- 
 oxidation of the bath. There are two methods for obtaining 
 the right carbon content: (a) by removing practically all the 
 carbon and then recarburizing; (6) by tapping when the carbon 
 has been reduced to the right percentage (catching the carbon on 
 the way down). In either case manganese (and sometimes 
 silicon) must be added (generally in the ladle) to remove the 
 remaining oxide in the metal. When the bath is in the right 
 : ondition as regards both composition and temperature, it 
 is run out of the furnace (tapped) by knocking out the material 
 in the tapping hole, if a stationary furnace, or, if a tilting fur- 
 nace, by lowering the tapping hole so the metal will flow out. 
 It is caught in a ladle, and poured into molds. Recarburization 
 (q.v.) is usually performed in the ladle, but may also be done in 
 the furnace before tapping. Instead of tapping into a ladle, 
 from which the molds are filled, the steel may be run into a 
 fore hearth, a small chamber or tank attached to the furnace, 
 and provided with holes in the bottom for filling the molds : its 
 object is to prevent chilling of the metal. Occasionally, after 
 tapping, some of the steel sticks around the tapping hole, and is 
 sometimes termed a dog collar. A chestnut is a lump of steel 
 sticking in the tapping hole. 
 
 Basic Open Hearth Process. As in the acid process, the 
 charge usually consists of pig iron (preferably molten) and scrap 
 (with ore and limestone in addition), but the materials are 
 not restricted as regards the phosphorus content; the sulphur, 
 however, should be low, as its elimination is very uncertain, 
 and at most slight; the silicon should also be low, to avoid 
 the use of an excessive amount of lime. Since the lining is 
 basic, ore can be charged initially without the danger of injuring 
 it. The actual elimination of the phosphorus is performed 
 by the lime, usually added as limestone, but occasionally burned 
 beforehand. With these differences the basic process closely 
 resembles the acid as regards melting and the preparation of 
 the bath. The proportion of pig is generally larger, and when- 
 ever practicable it is charged in the molten condition, as a mate- 
 rial saving in time and cost of handling results. 
 
 Under a superintendent a foreman has charge of a number 
 of furnaces and is responsible for the composition and the condi- 
 tion of the steel produced. The individual furnaces are operated 
 by a melter or first helper, an assistant melter or second helper, 
 and a cinder pitman, the last named cleaning out the cinder pit, 
 and assisting the others in fettling the furnace, i.e., repairing the 
 lining. There is also the gang necessary to load the stock, 
 prepare the ladles, pour the heats, etc. 
 
 Special open hearth processes are modifications of ordinary 
 practice designed to decrease cost, increase output, or make use 
 of material of troublesome composition (e.g., high phosphorus or 
 high silicon). The most important are the following: 
 
 Bertrand-Thiel process: This was designed especially for 
 the use of pig when the phosphorus is too high (about i to 2%) 
 to be treated in ordinary open hearth practice on account of the 
 
3 1 6 OPEN HEARTH PROCESS 
 
 bulky slag required, but too low for the basic Bessemer process. 
 It consists in charging pig, either alone or mixed with scrap, 
 together with ore and lime, in one basic furnace (primary furnace, 
 finer, or refiner) in which nearly all the phosphorus and silicon 
 and only a small part of the carbon are removed, the resulting, 
 partly purified metal, without any of the slag, being then trans- 
 ferred to another basic furnace (secondary furnace or finisher) in 
 which scrap, or ore, or both, together with some lime (occasion- 
 ally also a little pig) have previously been heated, when a very 
 rapid reaction takes place between the iron oxide formed and the 
 remaining impurities in the metal, which are quickly reduced 
 to below the required limits. The further details are the same as 
 in regular practice. The time required is about two to four 
 hours in each furnace. 
 
 Monell process: This is a modification of the pig and ore 
 process Ahich, however, may also employ scrap. It is ordi- 
 narily carried out in a fixed basic furnace, but a tilting furnace 
 will also serve. It consists in heating limestone and ore or some 
 form of iron oxide, the latter amounting to about 20 to 25 % of the 
 weight of the pig, until it becomes pasty, when the pig, in a 
 molten condition, is run in, and a violent reaction takes place. 
 A large amount of slag is formed which is run out of a special 
 notch into an auxiliary cinder pit (hunch pit), if a fixed furnace 
 is used, or out of the tapping hole, in the case of a tilting furnace, 
 by tilting it slightly. This slag contains about 90 % of the phos- 
 phorus and most of the silicon originally in the pig, about 2% 
 of carbon being still left in the bath. The heat is then worked 
 down and handled as in regular practice taking about the same 
 total time as an ordinary pig and scrap heat. 
 
 Talbot process or Talbot continuous process: This is a pig 
 and ore process although scrap is occasionally added. It depends 
 upon the rapid oxidation of the impurities contained in pig iron by 
 a liquid, highly ferruginous slag,' and is carried out in a basic open 
 hearth furnace, generally of the tilting type. The essential feature 
 of the process is always keeping a certain amount of metal in the 
 furnace (a) to dilute the impurities contained in the additions of 
 pig iron, and (b) to supply the heat necessary to keep the slag 
 very fluid. A tilting furnace of 200 tons capacity or over is 
 ordinarily employed, and from about one-quarter to one-third of 
 the finished steel is tapped out at one time. This having been 
 done, additions of ore or iron oxide and lime are made, and after 
 they are properly melted and incorporated in the slag, molten 
 pig iron is run in and a violent reaction takes place, most of the 
 phosphorus and silicon being eliminated in a few minutes, a large 
 part of the slag running out of the furnace. The bath is then ad- 
 justed as in ordinary practice, a part tapped, and the cycle of 
 operations repeated. A furnace is emptied completely only at 
 the end of the week or for repairs. The name Talbot furnace is 
 applied to an open hearth furnace in which this process is con- 
 ducted, but is really incorrect as the process does not require 
 any special type. A heat can be made in about three to four 
 
OPEN HEARTH PROCESS 3 1 7 
 
 hours. This process is sometimes run in conjunction with the 
 duplex process (see below) . 
 
 Surzycki process : This is the Talbot process carried out in 
 a stationary open hearth furnace, with tapping holes at different 
 heights for permitting the removal of the slag and portions of the 
 metal. 
 
 Campbell processes : These are two modifications of the open 
 hearth process. The first is simply a pig and ore process with 
 molten metal, and employing a tilting furnace of the Campbell 
 type. The foamy slag produced early in the process is prevented 
 from running out of the doors by properly tilting the furnace. 
 Any excess is allowed to run out through a slag notch between the 
 end of the furnace and the port which is prevented from chilling by 
 the flame constantly passing over it. After the foaming has 
 subsided the furnace is restored to its normal position and the heat 
 finished as usual. In the second modification the heat is com- 
 menced in a basic furnace, run at a low temperature^at which 
 most of the phosphorus and silicon, and some of the carbon, 
 manganese, and sulphur, are removed. The charge is then trans- 
 ferred to an acid furnace, and finished as usual, care being taken 
 to prevent, any of the basic slag from running in with the metal. 
 The initial charge may be constituted in various ways. The 
 object is to obtain any benefits supposed to accrue to acid steel. 
 
 Duplex process: This was designed for the use of ordinary 
 materials, but more especially for the use of pig iron high in 
 phosphorus and silicon. It consists in first blowing the molten 
 pig iron in an acid Bessemer converter to remove the silicon 
 and varying proportions of the carbon, the blown metal being 
 transferred to, and finished in, a basic open hearth furnace 
 (frequently tilting) according to regular practice. The blow- 
 ing takes about ten to fifteen minutes and the finishing in the 
 open hearth furnace from two to eight hours, depending upon 
 the size of the furnace and certain other conditions. 
 
 The following processes are of only general interest : 
 
 Berard process: Two furnaces were used, joined together, 
 and heated by gas. In one hearth air was blown into the bath 
 through tubes dipping beneath the surface and, after being 
 sufficiently refined, the charge was transferred to the other 
 hearth and finished. 
 
 Biederman and Harvey's modification consisted in return- 
 ing a part of the waste gases through the producer (a) to make 
 use of their sensible heat and (6) to obtain a gas containing less 
 nitrogen than when air alone is employed. 
 
 In Bouiniard's process a jet of air was used to stir up the 
 metal in much the same way as adopted by Ponsard. 
 
 In the Daelen-Pszczolka process hot air, under low pressure, 
 is blown on the surface of the bath. 
 
 Dyer's process consists in melting scrap with carbonaceous 
 material instead of with pig iron*, 
 
 M. Ehrenwerth and J. Rrochaska's process consisted in 
 employing briquettes of ore, charcoal or coke, and pig iron 
 which were to be charged in place of scrap. The ore and char- 
 
3 1 8 OPEN HEARTH PROCESS 
 
 coal were either placed in a mold, and molten pig iron run in, 
 or else were made into bricks around which the pig iron was cast. 
 
 P. Eyerman's process consists (a) in employing blast furnace 
 gas which is passed over heated carbon to convert the carbon 
 dioxide into carbon monoxide, and (6) in directing a jet of air 
 upon the bath. 
 
 Galy-Cazalet's process was an old method for refining pig 
 and making steel by injecting steam through the molten metal 
 contained in a cylindrical furnace, provided with several tuyeres, 
 or in an ordinary reverberatory furnace. It was not a success, 
 as the cooling effect of the steam was too great. 
 
 P. C. Gilchrist's process consists in melting pig and lime in a 
 basic furnace, the amount of lime being less than ordinarily re- 
 quired. At the same time a charge is blown in a basic Bessemer 
 converter with an excess of lime, and this molten scrap together 
 with the slag is added to the now molten charge in the open hearth 
 furnace, and the heat finished as usual. 
 
 W. B. Hughes' process was essentially a modification of the 
 Monell, and consisted in adding a suitable slag of iron ore and 
 lime in a molten condition after preparing it in a separate furnace. 
 
 In Krupp's process a furnace on the same principle as a 
 Ponsard furnace was used. It had a revolving hearth slightly 
 inclined to the horizontal and with tuyeres at one part. When 
 these were at the lowest point they blew air through the bath, 
 but at the highest point they were above the bath and the air 
 was stopped. 
 
 In the Lencauchez process the charge of pig or pig and scrap 
 is held molten at a low temperature to effect separation of the 
 manganese sulphide, after which the temperature is slightly 
 raised (but not to the point where the carbon is attacked), 
 and air is blown on the surface to effect the oxidation of the 
 phosphorus and silicon; ore or scale may also be used for this 
 purpose. The charge may be finished in the same or in another 
 furnace. 
 
 In the Lindenthal process pig iron is melted in a cupola and 
 run down through a closed conduit into a receiver. During 
 its passage jets of air are blown on it to oxidize the silicon and 
 phosphorus. From the tank furnace the metal (without any 
 slag) is run into a basic open hearth furnace and finished as usual. 
 
 NivenMcConnell's process was to desiliconize the pig iron in an 
 acid converter, at the same time reducing the carbon to about i %. 
 This metal was then transferred to a heated mixer from which 
 portions were taken periodically and finished in a basic open 
 hearth furnace as usual. 
 
 Parry and Llewellyn's process: Pig and ore, etc., are charged 
 in alternate layers and are heated just sufficiently to melt the 
 slag which is allowed to run off; the temperature is then raised 
 to melt the metal. The operation may be carried out in a 
 furnace with one or two hearths. 
 
 The Ponsard process consists in using a special furnace 
 known as a Ponsard furnace or Fornoconvertisseur having 
 a movable hearth and heated with gas. It is provided with 
 
OPEN HEARTH PROCESS OPTIMUM 3 1 9 
 
 tuyeres so that air can be blown through the metal during the 
 earlier stages, and then, by partially revolving the hearth, the 
 tuyeres are disconnected from the bath, and the process carried 
 on in the same way as in an ordinary open hearth furnace. 
 Another method was to use a hollow, water-cooled poker through 
 which air was blown into the bath to stir it up. 
 
 In the Schwartz process a large proportion of the charge is steel 
 scrap which is melted in a cupola and run into a bath of .pig iron 
 in a special type of furnace; it was claimed to be very rapid. 
 
 J. W. Thomas' process was devised for the manufacture of 
 steel direct from titaniferous ores. After crushing they were 
 mixed with coal, coke, or charcoal, 2% of lime, and i% of salt, 
 and were molded into briquettes which were added to a bath 
 of pig iron in an open hearth furnace, and the heat finished 
 as usual. The ore added in this way amounted to about 40% of 
 the weight of pig iron. 
 
 The Twynam process consists in adding a certain quantity 
 of briquettes, composed of iron ore and carbon, to the bath of 
 a basic open hearth furnace; it was claimed that the reduction 
 of the iron was very complete, but the process was used only 
 experimentally. 
 
 Wurtemberger's process was designed to hasten operations 
 by blowing air into the bath after the charge had melted down. 
 Air under a pressure of 7 to 8 pounds was introduced through i" 
 tuyeres, protected by clay, which were dipped into the bath. 
 It was found, however, that the lining of the furnace was 
 destroyed to such an extent that the gain in the actual process 
 was more than lost by the time required for repairs. 
 
 Wuth's process: The charge in an open hearth furnace was 
 composed of alternate layers of bar iron (wrought iron) and 
 graphite and was treated in the ordinary manner, spiegel or 
 ferro-manganese being added at the end of the heat. 
 
 Open Hearth Processes, Special. See page 315. 
 
 Open Hearth Steel. Steel made by the open hearth process (see 
 above) either acid or basic. 
 
 Open Iron. See page 343. 
 
 Open Order En Echelon. See page 283. 
 
 Open Pass. See page 405. 
 
 Open Pit. See page 57. 
 
 Open Sand Castings. See page 57. 
 
 Open Sand Mold. See page 299. 
 
 Open Sea. In the freezing of alloys: see page 54. 
 
 Open Spray Tuyere. See page 31. 
 
 Open Steel. See page 55. 
 
 Open Top. Of a blast furnace: see page 34. 
 
 Open Top Mold. See page 299. 
 
 Open Tuyere. See page 32. 
 
 Opposition Method. See page 209. 
 
 Optical Analysis. See page 284. 
 
 Optical Pyrometer. See page 207. 
 
 Optimum (rare). Best; e.g., optimum temperature means the best 
 or most favorable for a given reaction or condition. 
 
3 20 ORANGE HEAT ORE 
 
 Orange Heat. See page 210. 
 
 Ordinary Annealing. See page 231. 
 
 Ordinary English Pig Irons. See page 349. 
 
 Ordinary Ferro -Silicon. See page 354. 
 
 Ordinary Iron. Sometimes applied to cast iron castings to dis- 
 tinguish them from malleable castings. 
 
 Ordinary Line of Deformation. See page 126. 
 
 Ordinary Open Hearth Process. See page 310. 
 
 Ordinary Solder. See page 505. 
 
 Ordinary Steel. See page 443. 
 
 Ordinary Tool Steel. See page 445. 
 
 Ordinate. See Curve. 
 
 Ore. A natural mineral substance consisting of (a) one or more 
 (usually) metallic elements, generally in the combined state, and 
 (b) non-metallic elements as impurities or diluents, called the 
 gangue. It is understood that there shall be a sufficient propor- 
 tion of at least one of the metals to permit of its commercial 
 (profitable) extraction. Thus, a clay containing, say, 6% of iron 
 would not be considered as an ore of iron, as the iron could not be 
 recovered profitably. 
 
 Beneficiation or benefaction is the general term applied 
 to the preliminary treatment of an ore, having for its object 
 either the enrichment of its metallic contents or the removal of 
 injurious constituents, either by bodily removal or their change 
 into something less harmful. By roasting or calcination (q.v.) 
 moisture and volatile substances are driven off, and carbonaceous 
 or combustible matter is burned out. It is carried out, usually 
 with the admixture of solid fuel, in open piles, kilns, and some- 
 times in cupolas or small shaft furnaces, an excess of air being 
 necessary. The removal of a considerable part of the earthy 
 matter or gangue may be effected by washing in a washer or jig, 
 by taking advantage of the differences in the respective specific 
 gravities. The material is crushed and separated into lots, 
 consisting of pieces of nearly equal size, by suitable screens 
 (sizing), and is put in a jig or washer, the bottom of which has 
 water pulsating through it. The material is fed in at the top, 
 and the quicksand condition allows the constituents to separate 
 according to their specific gravities (sorting), and they are then 
 drawn off through separate holes. Only pieces of the same size 
 are treated together. The earliest type of shaft washer consisted 
 of a log 1 6 to 30 feet long fitted with blades revolving in an in- 
 clined trough, into which the ore is dumped and streams of water 
 added. As the log revolves, the blades cut the clay lumps and 
 force the sand, gravel and the ore up the incline of the trough to a 
 discharge opening, the water carrying away the clay. This was 
 sometimes called a buddle. It was improved by using two par- 
 allel logs in one trough, and, later, iron shafts replaced the logs. 
 In cone washers there are a series of perforated iron staves se- 
 cured to spiders, forming a cylinder with a conical end, which is 
 revolved by gearing, into which the ore is fed with a stream of 
 water. The staves have on their inner faces a series of blades or 
 cutters which break up the clay lumps, the water carrying this 
 
ORE BLOOM OUTSIDES 321 
 
 off, and the fine ore passes into a revolving screen which saves 
 all the ore above a determined size (Birkinbine). Cobbing 
 (Eng.) is a term used for hand picking. Magnetic concentration 
 or separation consists in the removal of nearly all the iron oxide, 
 in the form of the magnetic oxide (FesOO by the aid of powerful 
 magnets. If it does not already exist in that condition a pre- 
 liminary roasting may be necessary for its formation. This 
 treatment may be either for the purpose of enriching an ore of 
 iron or of removing iron when its presence is undesirable. The 
 finely crushed material may be brought into contact with magnets 
 so the magnetic particles are removed on traveling belts or re- 
 volving drums; another method is to deflect these particles 
 when falling in a stream past the magnet. Agglomerating fine 
 particles into coherent masses is dealt with under Briquette. 
 
 Ore Bloom. See page 135. 
 
 Ore Bridge. See page 32. 
 
 Ore Burden. See page 34. 
 
 Ore Distributing Devices. See page 32. 
 
 Ore Metal. See page 350. 
 
 Ore of Steel. See page 245. 
 
 Oreing; Oreing Down. See page 314. 
 
 Organic; Chemistry. See page 82. 
 
 Orient; Orientation. See page 119. 
 
 Oriented Lustre. See page 127. 
 
 Origin. In plotting curves: See Curve. 
 
 Orthobasic. See pages 122 and 350. 
 
 Orthorhombic System. Of crystallization: see page 120. 
 
 Orthosymmetric System. Of crystallization : see page 1 20. 
 
 Orthotomous. See page 1 24. 
 
 Orthotypous. See page 1 24. 
 
 Orton Cones. See page 209. 
 
 Osborne Process. See page 380. 
 
 Osmond and Cartaud's Method. Of etching: see page 288. 
 
 Osmond and Cartaud's Theory. Of slip bands: see page 283. 
 
 Osmond Method. Of quenching: see page 229. 
 
 Osmond's Reagents. For etching: see pages 287 and 288. 
 
 Osmond's Theory. (i) Of the allotropy of iron: see page 264; 
 (2) of hardening: see page 279. 
 
 Osmondite. See page 277. 
 
 Osmonditic Martensite. See page 276. 
 
 Osmose ; Osmotic Pressure. See Solution. 
 
 Osmund ; Osmund Furnace ; Process. See page 144. 
 
 Ostlund Process. See page 380. 
 
 Ostracoid. See page 290. 
 
 Otto Process. See page 144. 
 
 -ous. Chemical suffix: see page 88. 
 
 Out of Wind. Not twisted or alternately bent; a requirement in 
 some rail specifications. 
 
 Output. The production of a mill, plant, or company for a certain 
 period. 
 
 Outside Gage. See page 186. 
 
 Outsides; Outside Sheet. See page 431. 
 21 
 
322 OVAL GROOVE OXYGENITE PROCESS 
 
 Oval Groove; Pass. See page 405. 
 
 Oven. See page 181. 
 
 Over Iron. Surplus of (pig) iron melted for filling molds. 
 
 Overblow. See page 20. 
 
 Overburdened. Of a blast furnace: see page 34. 
 
 Overcarburization. See page 68. 
 
 Overhang. Of a tuyere: see page 31. 
 
 Overheating. See page 226. 
 
 Overheating Zone. See page 226. 
 
 Overstrain. See pages 216 and 334. 
 
 Overstrained Ferrite. See page 216. 
 
 Overstraining. In hardening: see page 279. 
 
 Overwork. See page 99. 
 
 Oxidated (rare). Oxidized. 
 
 Oxidation. See page 88. 
 
 Oxide. (i) The combination of another element with oxygen; 
 (2) oxide of iron or rust; (3) dross; (4) sometimes used for 
 "scale," e.g., black oxide. 
 
 Oxide Bottom. See Lining. 
 
 Oxide Coating. See page 362. 
 
 Oxide Film Theory. Of passivity: see page 364. 
 
 Oxide of Iron. See page 396. 
 
 Oxide Ore. See page 243. 
 
 Oxide Pearlite. See page 274. 
 
 Oxide Skin Theory; Oxide Theory. Of passivity: see page 364. 
 
 Oxone. A trade name for fused sodium peroxide. 
 
 Oxyacetylene Cutting ; Welding. See page 503. 
 
 Oxygen. O; at. wt., 16; melt. pt. -223 C. (369 F.); boil, 
 pt., -i82.sC. (-296.5 F.); sp. gr., 1.1056 (air = i); i liter 
 weighs 1.429 grams. It is a colorless, odorless, and tasteless 
 gas, forming one-fifth of the air by volume, and is found in 
 combination with various elements; it combines with all the 
 elements except fluorine. Iron oxide dissolved in iron makes 
 the metal both red-short and cold-short; in combination with 
 manganese this effect is not so noticeable, as the compound ap- 
 pears to be only mechanically held. Ledebur states that iron 
 containing combined oxygen up to 0.10% can be worked, but 
 that above this the metal is bad; the maximum content is about 
 0.25 to 0.30%. Uncombined oxygen is sometimes found 
 in blowholes or pockets. 
 
 Oxygen Charge Theory. Of passivity: see page 364. 
 
 Oxygen Film Theory ; Oxygen Theory. Of passivity: see page 364. 
 
 Oxygenated. Oxidized or impregnated with oxygen or oxide; 
 burnt. 
 
 Oxygenated Steel. See page 226. 
 
 Oxyhydrogen Cutting ; Welding. See page 503. 
 
 Oxygenite Process. A trade name for oxyacetylene welding : see 
 page 503. 
 
P. (i) Chemical symbol for phosphorus, q.v. ; (2) pressure. 
 
 Pb. Chemical symbol for lead (Latin, plumbum), q.v. 
 
 Pd. Chemical symbol for palladium: see page 84. 
 
 Pr. Chemical symbol for praseodymium: see page 84. 
 
 Pt. Chemical symbol for platinum : see page 84. 
 
 P. D. Pitch diameter; used in estimating the size of rolling mills; 
 the distance between the center points of pinions and gears. 
 
 P. &. M. S. Planished and machine straightened (of tires, etc.). 
 
 P. & O. Process. Pig and ore: see page 310. 
 
 P. & S. Process. Pig and scrap : see page 310. 
 
 Paal Steel Process. See page 78. 
 
 Pack. See page 430. 
 
 Packard Motor Company Process. See page 225. 
 
 Paddle. A flat tool employed by puddlers in preparing the lining. 
 
 Paddling Door. See Mixer. 
 
 Paint. See page 365. 
 
 Pair; Pair Furnace. See page 430. 
 
 Pallasite. See page 292. 
 
 Pallisades (obs.). Old name for bars. 
 
 Pallets (Eng.). Or bitts; the cast iron tools with chilled faces, used 
 in forging, which come in contact with the object to form it. 
 
 Pan (obs.). Ladle. 
 
 Pane. Also spelled pean, peen, pein, or pene ; it is the striking face 
 or the smaller and narrower end of a hammer head. It is termed 
 a ball pane when it is spherical in form : a cross pane when in the 
 form of a narrow, round-edged ridge placed at right angles to the 
 axis of the shaft; a straight pane when a ridge of the same charac- 
 ter runs longitudinally (Homer). 
 
 Paper Chill. See page 350. 
 
 Parallel Qrowth. See page 121. 
 
 Paramorph. See page 122. 
 
 Paris Gage. See page 188. 
 
 Parker Process. See page 369. 
 
 Parkes Process. See page 62. 
 
 Parrot Coal. See Coal. 
 
 Parry and Llewellyn Process. See page 318. 
 
 Parry Process. See page 387. 
 
 Part Chill Roll. See page 403. 
 
 Part Ingot. Butt ingot: see page 47. 
 
 Partial Cementation. See page 67. 
 
 Partial Fracture. See page 1 79. 
 
 Partially Fusible Cements. See page 69. 
 
 Parting. See page 123. 
 
 Parting Plane. See page 123. 
 
 Paiting Sand. See page 298. 
 
 Pass. See page 405. 
 
 Pass Over Mill. See page 408. 
 
 323 
 
324 PASSAGE PEEL 
 
 Passage (obs.). Tuyere. 
 
 Passivated Iron. See page 364. 
 
 Passive Break. In. connection with passivity: see page 364. 
 
 Passive Iron. See page 364. 
 
 Passive Resistance. See page 269. 
 
 Passive State. See page 364. 
 
 Passivified Iron; Passivity. See page 364. 
 
 Pasting. See page 300. 
 
 Patch. See page 432. 
 
 Patents. In coating sheets: see page 432. 
 
 Patent Blacking. See page 298. 
 
 Patent Steel ; Patented Steel. A steel heat treated so as to contain 
 
 a large proportion of sorbite; the same as sorbitic steel. 
 Patented Wire. See page 509. 
 Patience. See page 333. 
 Pattern. See page 296. 
 Pattern Maker's Rule. See page 296. 
 Paweck Process. See page 371. 
 Paxson-Deemer Converter. See page 24. 
 Pea Coal. See Coal. 
 Pea Coke. See page 97. 
 Pean. See Pane. 
 Pearlite. See page 273. 
 Pearlite -Cementite. See page 273. 
 Pearlite-Femte. See page 272. 
 Pearlite Point. See page 273. 
 Pearlite Range. See page 271. 
 Pearlitic Cementite. See page 273. 
 Pearlitic Ferrite. See page 272. 
 Pearlitic Range. See page 273. 
 Pearlitic Special Steels. See page 445- 
 Pearloid. See page 213. 
 Pearly Constituent. See page 273. . 
 Pearlyte. See page 273. 
 Peat. A dark brown fuel resulting from the decay of small 
 
 plants and mosses, occurring in bogs or swamps. It contains 
 
 up to 80% of water, and must accordingly be dried before using. 
 
 It is practically never employed in metallurgy. An average 
 
 sample, after drying, shows: 
 
 Carbon 56 . o% 
 
 Hydrogen 5.5 
 
 Oxygen 29 . 5 
 
 Nitrogen 1.5 
 
 Ash 7-5 
 
 Peat Charcoal ; Coke. Produced by the destructive distillation of 
 peat; it is not of metallurgical importance. 
 
 Peckham Process. See page 387. 
 
 Peel ; Peel Bar. (i) A long iron bar, flattened out at one end like a 
 spade, used for charging or withdrawing material from a furnace 
 by hand; (2) in charging machines, the arm which engages with 
 
PEEL CHARGING PHASE 325 
 
 the charging boxes to dump their contents in the furnace; (3) 
 the hoe-like plate on the end of a rabble. 
 
 Peel Charging. See page 313. 
 
 Peen ; Pein. See Pane. 
 
 Peening Test See page 482. 
 
 Peligot Method. See Iron. 
 
 Pellin Hardness-testing Machine. See page 478. 
 
 Peltier Effect. See page 209. 
 
 Peltoid. See page 290. 
 
 Pene. See Pane. 
 
 Penetration. Of carbon: see page 67. 
 
 Penetration Twin. See page 124. 
 
 Pentad; Pentavalent. See page 86. 
 
 Pepper Blister. See Blister. 
 
 Per-. Chemical prefix; see page 88. 
 
 Percarbide. See page 278. 
 
 Percussion Test. See page 481. 
 
 Percussive Electric Welding. See page 504. 
 
 Perfect Cleavage. See page 124. 
 
 Perfect Elasticity. See page 330. 
 
 Perfect Gas. See Gas. 
 
 Period of Elasticity. See page 334. 
 
 Periodic Law. See page 85. 
 
 Perlite. See page 273. 
 
 Permanent Distortion. See page 334. 
 
 Permanent Mold. See page 296. 
 
 Permanent Set. See pages 334 and 470. 
 
 Permanent Stretch. See page 336. 
 
 Permissible Working Stress. See page 468. 
 
 Peroxide Theory. Of passivity: see page 364. 
 
 Perpetual (obs.). Of the action of furnaces, processes, etc., con- 
 tinuous. 
 
 Perret Method. Of quenching: see page 229. 
 
 Perrins Process. See page 490. 
 
 Perturbation. See Curve. 
 
 Peter Process. See page 387. 
 
 Petroleum. A heavy yellowish or dark-colored oil of natural 
 origin. It has a high calorific power, and may contain a little 
 sulphur which is usually higher in the Russian than in ^the 
 American product. It is used to a certain extent for heating, 
 in which case it is injected into the furnace in the form of 
 spray. Its composition is approximately: 
 
 Carbon 85.0% 
 
 Hydrogen 13.5 
 
 Oxygen 1.5 
 
 Petroleum Furnace. A furnace in which petroleum is used for 
 fuel. It is usually sprayed in (atomized) with a jet of air or steam. 
 Pettitt Process. See page 22. 
 
 Pewter. Of rails which are soft and are battered in service. 
 Phantom. See page 289. 
 Phase; Phase Doctrine; Field. See Phase Rule. 
 
326 PHASE RULE 
 
 Phase Rule (Gibbs). Or phase doctrine (Roozebopm); a rule 
 for finding the number of phases that can exist in a system 
 containing a certain number of components, and having a cer- 
 tain number of degrees of freedom. It connects together the 
 number of components, degrees of freedom,, and possible 
 phases in equilibrium (Gibbs). A system is a body composed 
 of two or more components or phases. Bancroft defines 
 phase as "a mass chemically and physically homogeneous or 
 a mass of uniform concentration, the number of phases in a 
 system being the number of different homogeneous masses, or 
 the number of different concentrations;" and components as 
 "the substances of independently variable concentration in 
 the phase or system under consideration." Howe says: "The 
 components are the entities in play, the entities of which we 
 are studying the reciprocal behavior; the phases are the states, 
 physical and chemical, in which these components exist and 
 into which they pass." A careful distinction must be made 
 between the terms component and constituent: the constituents 
 of a system are the chemical elements or compounds present, 
 or capable of being present, as such; a constituent may occur in 
 more than one phase, or more than one constituent may unite 
 to form a single phase. For example, the constituent water may 
 exist at the same time both as ice and as water; the constituents 
 calcium oxide and carbon dioxide (each of which may be a com- 
 ponent) can unite to form the single component calcium carbo- 
 nate. To avoid confusion in the use of the term "phase" which 
 has this specific meaning, Turner has suggested that stage be 
 applied to indicate different conditions or structures as in the 
 case of pearlite. 
 
 In regard to the applications and limitations of the phase rule, 
 Howe says (Metallography^ 231): "It is a most remarkable and 
 valuable generalization; its conceptions help greatly toward 
 getting a broad outlook on metallography; but its misconception 
 has brought out a flood of obscuring writings. It tells us about 
 the constitution toward which alloys tend, that which they reach 
 when equilibrium is complete, when all tendencies have asserted 
 themselves and have been compiled with completely. But it 
 tells us nothing directly about the intermediate stages through 
 which those alloys pass in their attempt to reach that equilibrium, 
 nothing about alloys which are out of equilibrium. And what- 
 ever it may teach us indirectly about such inequilibrium (in- 
 complete equilibrium) is so hedged about with the direct and 
 indirect results of that inequilibrium that its application to any 
 individual case is fraught with the greatest difficulty." 
 
 Equilibrium is the condition of a system with regard _ to the 
 existing conditions. If the system is normal, i.e., that which can 
 exist under the given conditions, it is said to be in stable equi- 
 librium, otherwise in unstable equilibrium. If a system is in 
 unstable equilibrium, any change in the conditions tends to 
 cause a transformation to take place, i.e., a change to stable 
 equilibrium. Where, with change of temperature a transforma- 
 tion (thermal transformation) should occur at a definite tempera- 
 
PHASE RULE 327 
 
 ture (equilibrium or inversion temperature) but, owing to 
 molecular inertia (lag, hysteresis, or internal friction), cannot 
 do so instantaneously, a certain range of temperature may be 
 traversed before the tendency is great enough to cause the trans- 
 formation, after which the slighest disturbance will suffice. 
 During this range of temperature (metastable range) the system 
 is said to be in metastable or indifferent equilibrium ; beyond it 
 (labile range), in labile equilibrium. In the case of steel in 
 stable equilibrium above or below the transformation range, 
 reference is sometimes made respectively to the hot stable state 
 and the cold stable state. Thermal equilibrium is where the 
 members of a system are at the same temperature. The case 
 of the cooling of solutions which can be cooled without solidifi- 
 cation below the normal freezing point is called surfusion or 
 undercooling. Equilibrium diagrams are those which show the 
 normal relations between concentrations (composition) and 
 temperatures (and in some cases pressures); where metastable 
 states are plotted they are called metastable diagrams. In an 
 equilibrium diagram the different regions are termed phase 
 fields. Where the transformation occurs at the same tempera- 
 ture either on heating or cooling, it is said to be reversible ; if, 
 due to lag, .at different temperatures, an irreversible or non- 
 reversible transformation or process. If the transformation can 
 proceed only in one direction without any reverse change at all, 
 it is then termed monotropic. Where the radiation from a body 
 is counterbalanced by an equal evolution of heat, it is an isother- 
 mal transformation. A polymorphic transformation or allo- 
 tropic transformation is where the change is from one form to 
 another, as from gamma into alpha iron. 
 
 The phase rule may be written as an equation of equilibrium 
 which has been deduced from thermodynamical considerations as 
 
 F = C + 2 - P 
 
 F = degree of freedom; C = number of components; P = num- 
 ber of phases. The degree of freedom (also termed degree of 
 liberty, degree of constitutive freedom, and degree of variability) 
 is whether the existing constitution of a system has such a degree 
 of stability that it can survive a change of temperature or of 
 concentration, or cannot (Howe;. 
 
 An invariant or non-variant system is one which cannot 
 survive any change in temperature, pressure, or concentra- 
 tion; a mono variant system is one which can survive a change 
 in any one of these conditions, and a divariant system in one 
 which can survive a change in one of the conditions if a conform- 
 able change is made in one of the others. "The degree of 
 liberty of a non-variant system is o, that of a monovariant 
 system i, and of a divariant system 2" (Howe). A system with 
 n components can exist (a) if non-variant in n + 2 phases, (b) 
 if monovariant in n + i phases, and (c) if divariant in n phases. 
 A monovariant system is called a case of complete heterogene- 
 ous equilibrium, while a divariant system is known as a case 
 of incomplete heterogeneous equilibrium (Bancroft). "If a 
 
328 PHENOCELLULAR STRUCTURE PHOSPHORUS 
 
 system is uniform throughout its whole extent, and possesses in 
 every part identical physical properties and chemical composi- 
 tion, it is called homogeneous. Such is, for example, a solution 
 of sodium chloride in water. An equilibrium occurring in such a 
 homogeneous system (such as the equilibrium occurring in the 
 formation of an ester in alcoholic solution) is called homogeneous 
 equilibrium. If, however, the system consists of parts which 
 have different physical properties, perhaps also different chemical 
 properties, and which are marked off and separated from one 
 another by bounding surfaces, the system is said to be hetero- 
 geneous (non-homogeneous). Such a system is formed by ice, 
 water, and vapor, in which the three portions, each in itself 
 homogeneous, can be mechanically separated from one another. 
 Where equilibrium exists between different, physically distinct 
 parts it is known as heterogeneous equilibrium" (Findlay, 
 The Phase Rule, 5). To homogenize is sometimes used to signify 
 the obtaining of equilibrium for given conditions of temperature 
 and concentration. 
 
 Le Chatelier's theorem states that "any change in the fac- 
 tors of equilibrium from outside is followed by a reverse change 
 within the system." 
 
 Bancroft suggested that "it would be well to keep the term 
 adsorption for effects which may prove to be due primarily to 
 surface tension, and to treat absorption as the general term 
 applying to liquid and solid solvents, while occlusion would 
 refer only to the formation of solid solutions." With the ob- 
 ject of explaining this adsorption theory, W. R. Whitney says 
 (Proc. Am. Electrochem. Soc., 1915, 187): "I cannot accurately 
 differentiate between absorption and adsorption. We usually 
 have adsorption in phenomena going on at a surface when some- 
 thing comes to it and clings there. But a sponge is made of a lot 
 of interior surfaces, therefore a sponge would adsorb and not 
 absorb. I think you will find the water is held on the surface 
 in the pores. Glass surfaces adsorb from solutions; if you 
 analyze the surface solution you will find the material in the solu- 
 tion has increased in concentration on the surface of the glass." 
 
 Phenocellular Structure. See page 126. 
 
 Phenocryst. Se page 125. 
 
 Philosopher's Wool. See Zinc. 
 
 Phosphate Ore. See page 244. 
 
 Phosphide Phosphorus. See Phosphorus. 
 
 Phospho-Ferrite. See page 272. : 7 .-; u \ 
 
 Phospho-Manganese. See page 353. 
 
 Phosphoretic. Phosphorous; containing phosphorus. 
 
 Phosphoretic (Phosphoric) Cast Iron ; Pig. See page 346. 
 
 Phosphorous (adj.). Containing phosphorus. 
 
 Phosphorus. (i) In iron ore: see page 243; (2) influence on 
 corrosion: see page 366. 
 
 Phosphorus. P; at. wt., 31; melt, pt., 43.3 C. (78 F.); boil, 
 pt., 269 C. (516 F.); sp. gr., yellow, 1.82, red, 2.25. It is 
 never found in the free state, its most important occurrence 
 being in combination with oxygen and various metallic ele- 
 
PHOSPHORUS ADDITIONS PHYSICAL PROPERTIES 329 
 
 ments, called phosphates. In its elemental condition it may 
 occur in one of two allotropic forms: the ordinary variety which 
 is a colorless or yellow wax-like poisonous solid, and another 
 variety of reddish color, and non-poisonous, obtained by heat- 
 ing the ordinary variety to between 240 and 250 G. (464 
 and 482 F.) with exclusion of air; when heated to above 260 
 C. (500 F.) it passes back to the yellow variety. This latter 
 is very inflammable and must be kept under water. It is the 
 most undesirable impurity which occurs in steel, causing cold- 
 shortness and, perhaps, to a slight extent, red-shortness. It 
 is usually limited to 0.05% in basic, and 0.10% in acid steel, 
 except for some special purpose. In cast iron it makes the 
 molten metal more fluid. Baron Juptner suggests that in 
 analogy to the different modifications of carbon it is possible 
 to describe one form of phosphorus which, upon treatment of 
 steel with dilute acids, escapes as PH 3 , and which causes cold- 
 shortness, as hardening phosphorus, while the modification, 
 insoluble in dilute acids, may be named phosphide phosphorus. 
 
 Phosphorus Additions. See Recarburization. 
 
 Phosphorus Banding. See page 289. 
 
 Phosphorus Reagent. For detecting phosphorus on etching: see 
 page 287. 
 
 Photogram; Photograph. See page 284. 
 
 Photometer. See page 208. 
 
 Photomicrograph; micrography; microscopy. Seepage 284. 
 
 Physic ; Physick ; Physicking. A term, usually restricted to the 
 puddling and the crucible process, for an addition made with the 
 object of assisting in the removal of the impurities, and the more 
 rapid working of the heat; it may act chemically or simply as a 
 flux. It may consist of a mixture of manganese dioxide with salt 
 or a little ground charcoal, sal ammoniac, prussiate of potash, 
 ground glass, fluorspar, etc. 
 
 Physical Analysis. See page 284. 
 
 Physical Formulae. See page 337. 
 
 Physical Hardness. See page 331. 
 
 Physical Metallurgy. Suggested by Rosenhain for "that great 
 branch of the knowledge of metals which has to a large extent 
 grown up during the last fifty years a branch which concerns 
 itself with the nature, properties and behavior of metals and of 
 alloys as such, as distinct from the far older branch of metallurgy 
 which deals with the reduction of metals from their ores. Hith- 
 erto the term Metallurgy has indeed been almost entirely confined 
 to this latter meaning, and those who have grown old in this idea 
 are a little apt to resent an innovation which gives to the old term 
 Metallurgy a wider and more general meaning than it formerly 
 bore so as to include the newer knowledge of metals. This inevit- 
 able widening ot the old term, however, demands a subdivision, 
 so that the department of metallurgy which relates to the reduc- 
 tion of metals and their refining may well be termed Process or 
 Chemical Metallurgy, leaving to tne younger branch of the 
 science the newer term Physical Metallurgy." (Phys. Met,, i.) 
 
 Physical Properties. (See also Testing.) Those properties ex- 
 
330 PHYSICAL PROPERTIES 
 
 hibited by a body which do not involve any change in its chemical 
 composition. The general treatment of the subject in treatises 
 and text books is usually under the title of Strength of Materials 
 or Properties of Materials for which Ewing gives the following 
 definition (Ency. Brit.): "That part of the theory of engineering 
 which deals with the nature and effects of stresses in the parts of 
 engineering structures. Its principal object is to determine the 
 proper size and form of pieces which have to bear given loads, or, 
 conversely, to determine the loads which can be safely applied to 
 pieces whose dimensions and arrangement are already given. 
 It also treats of the relation between the applied loads and the 
 changes of form which they cause. The subject comprises 
 experimental investigation of the properties of materials as to 
 strength and elasticity, and a mathematical discussion of the 
 stresses in ties, struts, beams, shafts and other elements of struc- 
 tures and machines." When a body possesses the same proper- 
 ties, no matter in what direction it is tested, it is said to be 
 isotropic; when they differ in different directions, anisotropic, 
 aeolotropic or eplotropic. Those here discussed are principally 
 what are met with in testing (q.v.) materials. 
 
 The strength or tenacity of a body is its resistance to rupture 
 or breaking, and may be of the following kinds: 
 
 1. Tensile (tensional) strength (sometimes referred to as 
 tensile strain) : resistance to being pulled apart. 
 
 2. Compressive strength: resistance to being crushed. 
 
 3. Shearing strength: resistance to being sheared or cut; 
 the next two are also of this kind. 
 
 4. Torsional strength: resistance to torsion or being twisted. 
 
 5. Bending, transverse or flexural strength: resistance to 
 flexure or bending. 
 
 A division may also be made into 
 
 6. Static strength: resistance to loads slowly and gradually 
 applied. 
 
 7. Dynamic strength: resistance to loads suddenly applied 
 (shocks) or repeated stresses. 
 
 Elasticity is the ability of a body to regain its original shape 
 after^ having been distorted. This definition covers perfect 
 elasticity ; however as bodies seldom meet this condition entirely 
 they are said in such case to possess imperfect elasticity. The 
 distortion from which an elastic body can recover may be termed 
 elastic deformation or elastic strain and the maximum stress 
 under which this condition obtains is called the elastic limit, 
 corresponding to the elastic strength or elastic limit strength for 
 the material. In the Quarterly Mathematical Journal of April, 
 1855, Sir William Thompson (Lord Kelvin) discussed at some 
 length the thermo -elastic properties of material, and showed 
 mathematically that elastic matter when stressed absorbs heat, 
 that is, its temperature as indicated by a thermometer is lowered; 
 but when the stressing is carried beyond the elastic limit and the 
 strain becomes permanent, the body gives out heat, that is, its 
 temperature as indicated by a thermometer, rises (Capp). 
 Rigidity or stiffness is the property by virtue of which bodies 
 resist change of snape. 
 
PHYSICAL PROPERTIES 331 
 
 Resilience, or the work of resistance of materials, is frequently 
 used in the same sense as elasticity. It connotes springiness and 
 should properly be restricted to the amount of work absorbed 
 when a body is stressed within its elastic limit and which can be 
 recovered when the stress is removed; this is sometimes also 
 termed elastic resilience which however seems redundant. De- 
 pending upon the nature of the stress there may be tensile or 
 compressive resilience, shearing, bending or flexural resilience, 
 and torsional resilience. The modulus of resilience is the work 
 
 Eer unit volume in stressing up to the elastic limit and is equiva- 
 mt to half the product of the elastic limit strength and the cor- 
 responding unit deformation. 
 
 The opposite of elasticity or resilience, when the slightest 
 distortion or deformation (change of form) is permanent is 
 called plasticity: no substance possesses either property ab- 
 solutely. Plastic or viscous materials flow under a compressive 
 load. 
 
 Hardness is resistance to indentation, or abrasion or attrition 
 (wear from rubbing or crushing). Abrasive hardness is also 
 known as scratch hardness. Static hardness is where the force 
 acts relatively slowly as in the Brinell ball test (see Testing, page 
 477) or ordinary abrasion. Dynamic hardness is where the 
 force acts suddenly as in the scleroscope test (see Testing, page 
 478); this term has also been suggested by Turner to cover 
 resistance to the action of running water, to a sand blast, etc. 
 A substance may be said to possess chemical hardness when 
 this is due principally to its composition; physical hardness 
 when due to its chemical and mechanical structure; and mechan- 
 ical hardness when resulting from being worked, particularly 
 cold, also known as work hardness and strain hardness. 
 
 Brittleness is the tendency to rupture under shock or loads 
 suddenly applied; the opposite of this is toughness. Hardness 
 and brittleness are not necessarily allied, as shown by manganese 
 steel which is very hard and yet at the same time may be tougher 
 than ordinary steel. 
 
 Malleability is the property which permits a metal to be ham- 
 mered or pressed out into shape without cracking: ductility 
 is practically a synonymous term but is applied more especially 
 to that form of toughness which permits a metal to be drawn or 
 drawn down. It was noted by A. LeChatelier that between 80 
 and 120 C. (175 and 250 F.) there was a critical mechanical 
 temperature at which steel exhibited its minimum ductility. 
 Ordinarily it is understood that any reference to the ductility 
 of a body means when it is cold, otherwise the terms hot ductility 
 and cold ductility (only in contradistinction) would be used. 
 The term cito-ductile is sometimes applied to a body which can 
 be stretched suddenly without rupture. 
 
 A force acting on a body is known as a stress : if it affects the 
 entire body (e.g., gravity) it is termed a body force or volume 
 force ; if it acts only upon local portions (the pressure of one 
 object against another) it is a surface force or surface traction. 
 A force or stress may act either from outside a body (external 
 
332 PHYSICAL PROPERTIES 
 
 force) or from within (internal force). "The terms axial forces 
 and axial stresses are used to include both tension and compres- 
 sion acting upon a bar, it being understood that the resultant 
 of the applied forces acts along the axis of the bar. The axial 
 force P is often called a load. It is always understood, unless 
 otherwise stated, that the stresses due to an axial load or 
 concentric load are uniformly distributed over the section area, 
 and this is called the case of simple axial stress" (Merriman). 
 Stresses (or strains) may be (a) normal or direct (tensile or 
 compressive), (b) shearing, flexural or tangential, and (c) a 
 component of the two or oblique. If the stress is in only one 
 direction it is a simple stress ; if in different directions a compound 
 stress. "It may be shown that any state of stress which can 
 possibly exist at any point of a body may be produced by the 
 joint action of three simple pull or push stresses in three suitably 
 chosen directions at right angles to. each other. These three 
 axes are called principal stresses, and their directions are called 
 axes of principal stress. These axes have the important prop- 
 erty that the intensity of stress along one of them is greater, and 
 along another it is less, than in any other direction. These are 
 called, . respectively, the axes of greatest and least principal 
 stress" (Ewing). As in the case of a liquid at rest, but where 
 there are balanced stresses exerted upon it, such an effect is 
 termed a fluid stress. Those directly produced by loadings may 
 be called primary stresses ; and further stresses, acting in con- 
 junction with these, secondary stresses (Carpenter). 
 
 The term pure stress is employed where only one kind of 
 stress exists. Where a plane is acted upon only by forces normal 
 to it, this is sometimes called pure normal stress. Where a plane 
 is acted upon only by forces parallel to it it is sometimes called 
 pure shearing stress. Another use of the term pure stress is 
 with respect to any and all planes that can be imagined drawn 
 in the interior of a body. Where the forces acting upon the body 
 have such values that there can be no shearing stresses within it, 
 the case is called one of pure internal normal stress. The term 
 pure flexure is used for a part of a beam where there are no ver- 
 tical shears (Merriman). True stresses are those actually 
 determined while those simply calculated are apparent stresses. 
 Owing to various conditions, such as irregular cooling, cold 
 distortion, etc., an unstressed body is only theoretically possible, 
 and consequently all bodies are more or less (internally) self- 
 stressed or self-strained. A body with internal strains at a 
 minimum is said by Pearson to be in a state of ease. Heyn calls 
 outside stresses acting on such a body additional stresses. 
 Internal strains may be set up by unequal expansion or con- 
 traction in different parts of a piece due to irregular heating or cool- 
 ing or to transformations (transformation strain) of state (see 
 Metallography, p. 264). In material cold drawn in the direction 
 of its axis the outer layers are under tension and the inner layers 
 are under compression, whereas in the case of cold-rolled and 
 cold-hammered bars the reverse is true. In either case if the 
 tensile stresses are excessive rupture may be caused (spontaneous 
 
PHYSICAL PROPERTIES 333 
 
 cracking in the case of the cold-rolled or cold-hammered bars, 
 internal rupture, fracture, or defect). If such strains are not 
 excessive they may be removed by a suitable annealing (see 
 Heat Treatment, p. 231). When a body is struck, vibrations or 
 waves are set up in it, the effect depending on the frequency or 
 number per second. In conducting experiments the stress 
 originally present is known as the initial stress. The range of 
 stress is the algebraic difference between the maximum and the 
 minimum; the mean stress is half the algebraic sum. 
 
 The effect of a stress depends largely upon the manner in 
 which it is applied. Thus when suddenly applied, as a blow 
 (sudden load, accelerated stress, impact or shock), it has a con- 
 siderably greater effect than a stress slowly and steadily applied 
 (static stress or load).' Again, if the stress is repeated, i.e., 
 applied a great number of times, each application being made 
 before the material has been given time to recover from the 
 preceding, it will eventually break, even though the stress is 
 below the elastic limit as ordinarily understood. For practical 
 purposes, if the stress is sufficiently small, and below what may be 
 termed the fatigue limit or endurance limit, its repetition may be 
 indefinitely continued. Alternate stresses are similar in effect, 
 but are where the force acts first in one direction and then in the 
 opposite. It will therefore be seen that stresses may vary from 
 + to (e.g., tensile to compressive) or from a higher to a lower 
 value with the same sign (stress difference or limiting stresses). 
 They are termed dynamic stresses or loads (producing corre- 
 sponding dynamic deformations or strains) and are covered by 
 Wohler's law, which may be stated thus: Rupture of material 
 may be caused by repeated vibrations, none of which attains the 
 actual breaking limit; the difference of the limiting strains are 
 sufficient for the rupture of the material. When a metal is 
 subjected to a stress its component particles may become so 
 disturbed and disarranged (see Plastic Deformation, under 
 Metallography, p. 279), within the limits of elasticity be it 
 understood, that after the removal of the stress, and it is left 
 at rest, some time, and in certain cases considerable time, must 
 elapse before the particles will have spontaneously readjusted 
 themselves as they originally were. The term fatigue or elastic 
 break-down, is meant to indicate such disturbance; the terms 
 refreshment, recovery, aging, or elastic after-working, restora- 
 tion of the metal to its original state; and the term patience, the 
 time required for that restoration. If a body is subjected to a 
 change of temperature and is acted upon by a force which tends to 
 prevent the corresponding expansion or contraction, stresses are 
 set up which may be termed temperature stresses. 
 
 Intensity of stress (unit stress) is the force exerted per unit of 
 area; in English units, pounds or gross tons (England) per square 
 inch, and in metric units, kilograms per square millimeter or 
 per square centimeter. 
 
 Every stress, no matter how small, produces a corresponding 
 strain (tensile strain, compressive strain, etc.) or deformation in 
 the shape of the body acted upon, and which increases with the 
 
334 PHYSICAL PROPERTIES 
 
 stress. The stress and the corresponding strain are directly 
 proportional up to a certain point, called the elastic limit (limit 
 of linear elasticity, etc.), below which, by removing the stress, 
 the corresponding strain disappears and the body returns to its 
 original shape, or, in other words, is elastic. This fact constitutes 
 Hooke's law or the limit of proportionality. After this period 
 has passed, the strain increases more rapidly than the stress 
 causing it, and if the stress be now removed, the body will 
 partially, but not entirely, regain its original dimensions, as it 
 has received a permanent distortion (permanent set, overstrain, 
 plastic strain). Gerstner's law is that elastic deformations are 
 proportional to the loads producing them both before and after 
 permanent set. Relative deformation is the deformation per 
 linear unit. The period before the elastic limit is reached is 
 known as the period of elasticity. The point at which the elastic 
 limit is exceeded is called the yield point or breaking-down point. 
 If a material has been overstrained (a .permanent set produced) 
 and is immediately reloaded it will be found to have no true 
 elastic limit (although its yield point will be about the same), also 
 its ductility is lowered. If it is allowed to recover by resting 
 (aging) several days or weeks, or is heated for a few minutes at 
 the temperature of boiling water, a true elastic limit will be found, 
 but higher than in the original material, and also the ductility 
 will be increased (spontaneous annealing). If, instead of again 
 testing in tension, it is tested in compression, the elastic limit will 
 be lower than in the original material, but not necessarily to the 
 extent that the tensile elastic limit and yield point have been 
 raised. This is kno wn as the effect of hardening, or the hardening 
 effect of permanent set. Vical's experiment proved that heavily 
 loaded material is likely to yield ultimately under loads that are 
 sustained for short periods without apparent injury. Emory's 
 process for increasing the elastic limit of material (particularly 
 structural material such as eye bars) consisted in cold straining 
 the material tensily slightly above its elastic limit or yield point; 
 the load was then removed and the material annealed at a very 
 low temperature, say not over 300 or 400 C. (570 or 750 F.). 
 The effect of the cold straining was to destroy the true elasticity 
 limit of the material which was restored to a higher point than 
 before, by the annealing. The modulus (rarely module) or 
 coefficient of elasticity or Young's modulus (first applied for 
 extension only) is the ratio, within the limits of elasticity, of the 
 stress to the corresponding strain, e.g., the load in pounds per 
 square inch divided by the deformation in fractions of an inch for 
 each inch of gaged length of the specimen. It may be said to be 
 the stress which would have to be applied to stretch the piece to 
 double its original length assuming it to be perfectly elastic. 
 This, of course, is impossible as the limit of elasticity of prac- 
 tically any material is passed when it has been deformed to about 
 o.ooi of its length. For steel in tension or compression it 
 varies from about 26,000,000 to 31,000,000 pounds per square 
 inch, the more usual limits being between 28,000,000 and 
 30,000,000 pounds per square inch. The corresponding values 
 
PHYSICAL PROPERTIES 
 
 335 
 
 in the metric system (kilograms per square millimeter), wide 
 limits, 1828 to 2179; usual limits, 1969 to 2109. The values for a 
 material in tension (modulus of longitudinal extension or ex- 
 tensibility) are generally slightly higher than those for compres- 
 sion (modulus of compression or compressibility or bulk modu- 
 lus). The modulus of elasticity "may also be called modulus of 
 stiffness since it is a direct measure of the rigidity of a body 
 (modulus of rigidity) or an inverse measure of its flexibility; a 
 modulus of flexibility would be the reciprocal of the modulus of 
 elasticity, but Prof. A. B. W. Kennedy has taken for such a 
 modulus of specific extension the stretch in thousandths of an 
 ^ inch on a length of 10 inches under a stress of 1000 pounds per 
 * square inch. Its reciprocal multiplied by 10,000,000 is the 
 modulus of elasticity" (Johnson). The shearing modulus of 
 elasticity (modulus of elasticity for shear; modulus of shear) is 
 the ratio of the shearing stress to the corresponding an gular strain, 
 
 Steel 
 
 White Cast Iron 
 
 1OO 
 
 ^ 
 
 , / 
 
 -^ 
 
 ~^*rc 
 
 
 
 
 
 u 
 
 160000 
 12OOOO 
 
 
 V; 
 
 f 
 
 
 "<: 
 
 HJ..'!j/ 
 
 S,^ _^~ 
 
 ^Jfe 
 .--^X 
 
 -~ ' 
 
 :^ 
 
 - 
 
 8OOOO 
 
 
 9>4 
 
 ^ 
 
 
 
 ktdnes*-, 
 , Mtf 
 
 <*<& 
 
 l\ 
 g> 
 
 ^ 
 
 
 """"" . 
 
 ^ 
 
 4QOOO 
 
 o 
 
 f 
 
 \ p 
 
 .*< 
 
 r 
 
 
 
 ^ 
 
 . _Iena 
 
 City 
 
 F 
 
 
 
 1.0 1.5 2.0 2.5 3.0 3.5 4.O 4,5 
 
 Percentage of Carbon 
 
 LEGEND; Tenacity 
 
 Hardness 
 
 Ductility I 
 
 Percent Ferrite or Cementite __.__._ 
 
 FIG. 48. Physical properties and assumed microscopic constitu- 
 tion of the pearlite series, graphiteless steel slowly cooled, and 
 white cast iron. (Howe, "Iron, Steel and Other Alloys.") 
 
 and is two-fifths of the modulus for extension. " The volumetric 
 modulus of elasticity of a solid body for an equal stress in all 
 directions is two-thirds of Young's modulus which applies only to 
 direct stress in one plane and its accompanying deformation" 
 (Johnson). For compression it is termed the modulus of cubic 
 compressibility. 
 
 If the stress be increased sufficiently, the body will eventually 
 be broken or else distorted to such an extent that the force can no 
 longer act, and in the former case this maximum stress (maximum 
 load) applied is known as the ultimate strength of the body 
 (sometimes referred to as the ultimate stress). The elastic 
 ratio is the ratio between the elastic limit and the ultimate 
 strength, the former figure being divided by the latter ;|it is 
 sometimes expressed as a percentage. 
 
336 PHYSICAL PROPERTIES 
 
 The maximum tensile stress (tensile strength) does not neces- 
 sarily correspond with the breaking load (breaking or tearing 
 stress) at the moment of rupture, although this distinction is not 
 always made, on account of the reduced cross-section. Here 
 as the material is stretched longitudinally, it is obvious that it 
 must contract with respect to its cross-section. This contrac- 
 tion, however, even in the case of a body having originally the 
 same cross-section throughout, is not uniform, But at some por- 
 tion an action called necking or bottling occurs, i.e., the contrac- 
 tion is much more pronounced and rupture will occur there. 
 The amount of permanent stretch upon rupture is called the 
 elongation (extension or stretch) and is usually expressed as a 
 percentage of the original length, e.g., 25% in 8 inches. This 
 percentage is a function of the relation of length to cross-section 
 (see Testing, page 473) and therefore, in reporting it, the di- 
 mensions of the specimen in question should always be given. 
 (Tensile or compressive deformations are stated in terms of the 
 original length or thickness; shearing or torsional deformations 
 in radian (TT) measure. The difference between the original 
 cross-sectional area and that at the point of rupture (the small- 
 est) is called the reduction of area (contraction of area, or rarely, 
 contraction of section, or striction), and is generally stated as a 
 percentage of the original. Specific tenacity is the tensile 
 "strength of a material expressed as the length of a bar which, 
 if suspended vertically, is just sufficient to break under its own 
 weight" (Rosenhain). "It is a fact of observation that when a 
 metal body is elongated by an external force from / to / + \l 
 (inside the elastic limit), it contracts laterally about one-fourth 
 of its proportionate elongation. Hence, if the original diameter 
 
 were d, its diameter after stretching would be d d. This 
 
 4 
 
 ratio of lateral to longitudinal deformation, under longitudinal 
 external forces, is called Ppisson's ratio" (Johnson). 
 
 In the case of compression "there is no such thing as an ulti- 
 mate strength of a plastic body. There is, however, a definite 
 apparent elastic limit, the same as in tension. Beyond this the 
 material simply spreads" (Johnson). This is, therefore, the 
 elastic compressive strength or compressive strength. "The 
 term bearing compression is in common use for the sidewise 
 compression brought upon a rivet by the tension in the plate. 
 Rivets are more apt to fail by shearing than by bearing com- 
 pression" (Merriman). The ductility is indicated by the 
 shortening or ultimate shortening (upon rupture) which however 
 is rarely determined, for obvious reasons, particularly in the case 
 of very duclile bodies. 
 
 "When a beam is laid upon supports its weight and the 
 weight of its load are borne by the supports which exert reactions 
 upward against the beam. The vertical shear for any section of 
 a beam is a measure of the tendency to shearing along that 
 section . . . being greatest near the supports . . . The usual 
 method of failure of beams is by cross-breaking or transverse 
 rupture. This is caused by the external forces producingjrota- 
 
PHYSICAL PROPERTIES 337 
 
 tion around some point in the section of failure (plane of shear). 
 Resisting shear is the name given to the algebraic sum of the 
 internal vertical stresses in any section, and vertical shear is the 
 name for the algebraic sum of the external vertical forces on the left 
 of the section. Resisting moment is the name given to the alge- 
 braic sum of the moments of the internal horizontal stresses with 
 reference to a point in the section, and bending moment is the 
 name for the algebraic sum of the moments of the external forces 
 on either side of the section with reference to the same point" 
 (Merriman, Mechanics of Materials, 93-98). Simple shear is 
 where there are only two principal opposite forces of equal value. 
 Single shear (in the case of rivets, for example) is where the 
 object is supported at only one end; in the case of double shear 
 both ends are supported. Flexural rigidity is used in the same 
 sense as flexural or shearing strength, the resistance offered to 
 flexural stress. Transverse strain or deformation is also termed 
 detrusion. If a beam or bar is supported at the ends against a 
 force, within the elastic limit, acting at some point between, 
 bending will result whereby the concave surface is in compres- 
 sion and the convex surface is in tension. It is assumed that 
 the material is composed of infinitely thin leaves or fibers and 
 the term fiber stress or maximum fiber stress is used to indicate 
 the force acting at the surfaces which are necessarily affected to 
 the greatest extent since they undergo the greatest amount of 
 deformation. Since the force changes from plus to minus there 
 must be some plane where it is zero, and this is called the neutral 
 surface ; the neutral axis is the line of intersection of the neutral 
 surface with any plane normal to it. 
 
 Physical Formulae. From time to time empirical formulae 
 have been proposed to calculate the physical (tensile) properties 
 or as a basis for a direct comparison of the properties of two 
 samples either of the same composition but differently treated, or 
 of different composition and similar or dissimilar treatment. 
 Of the first class (tensile properties or structural properties) it 
 may be said they are based on the assumption that the properties 
 are additive, i.e., proportional to the composition or a summation 
 of the properties of the individual components. This, un- 
 fortunately for the purpose, is usually far from being the case, 
 and in addition there are so many other factors entering into the 
 problem, such as size, mechanical and thermal treatment, that to 
 determine accurately their bearing would generally be much 
 more difficult, and even the real result would be left in consider- 
 able doubt, than to make a direct test. 
 
 Tensile Formulae. These in turn may be divided into: (a) 
 chemical formulae, based on ultimate chemical composition; 
 (b) structural formulae, based on microscopic or proximate 
 chemical analysis. Sauveur distinguishes between proximate 
 structural composition, e.g., ferrite and pearlite, or cementite and 
 pearlite, and ultimate structural composition, e.g., the total 
 ferrite and cementite both free and contained in pearlite. 
 
 (i) Chemical Formulae. Bauschinger's formula for tensile 
 strength of Bessemer steel : 
 22 
 
338 PHYSICAL PROPERTIES 
 
 T. S. = 43-64 d + C 2 ) 
 
 T. S. in kilograms per square millimeter; C = carbon %. 
 H. H. Campbell's formulae for tensile strength: 
 
 (a) for acid steel, carbon by combustion: 
 
 \ T. S. = 40,000 + 1000 C + 1000 P + x Mn + R 
 
 (b) for basic steel, carbon by combustion: 
 
 T. S. = 41,500 + 770 C + 1000 P + y Mn + R 
 
 The strength is in pounds per square inc'h. C, P, and Mn are the 
 values of these elements given in hundredths of a percent. The 
 coefficients x and y are given in tables (see Manufacture and 
 Properties of Iron and Steel, 391). R is a variable to allow for 
 heat treatment which must be specially determined. See 
 modified formulae below as proposed by Merriman. 
 
 Cunningham's formula for tensile strength for acid and basic 
 open hearth steels, based on his values for pure iron, carbon, and 
 phosphorus, may be stated as follows : 
 
 T. S. = 40,000 + 100,000 C + 100,000 P 
 
 T.S. in pounds per square inch; values for C and P in percent. 
 Deshayes' formulae : 
 
 (a) Tensile strength: 
 
 T. S. = 30.09 + 18.05 C + 36.11 C 2 
 
 T. S. in kilograms per square millimeter; C = percentage of 
 carbon. 
 
 (6) Elongation: 
 
 E 2 o = 42 - 56 C 
 
 EIO = 35 30 C 
 
 E 2 o and EIO are percentage of elongation in lengths of 20 and 10 
 centimeters (approximately 8" and 4") respectively; C = per- 
 centage of carbon. 
 Howe's formulae for elongation, percent in ^ inches : 
 
 (a) for steel under 0.50% carbon: 
 
 E = 33 -6o(C 2 +o.i) 
 
 (b) for steel between 0.50 and 1.00% carbon: 
 
 E = 12 11.9 ^/C - 0.5 
 
 Merriman's formulae for tensile strength : 
 (a) Deduced from Campbell's formulas: 
 
 Acid steel: T. S. = 40,000 + 68,000 C + 100,000 P + 80,000 
 CM; 
 
 Basic steel: T. S. = 38,800 + 65,000 C + 100,000 P + 9000 
 M + 40,000 CM. 
 
 T. S. in pounds per square inch; values for C, P, and M (Mn) are 
 in percent (not in hundredths of a percent as in Campbell's 
 original formulae). 
 
PHYSICAL PROPERTIES 339 
 
 (b) Approximate values for open hearth steel unannealed: 
 
 Acid steel: 45,000 + 108,000 C 
 Basic steel: 45,000 + 90,000 C 
 
 Salom's formula for tensile strength (average values) : 
 T. S. = 31-74 + 70-53 C 
 
 T. S. in kilograms per square millimeter; C = percentage of 
 carbon. 
 
 Sauveur's formulae (Metal lor gaphy, p. 138 et seq.): 
 (a) Tensile strength : 
 
 (j) Hypo-eutectoid steels (carbon not over 0.834%) 
 
 T. S. = 50,000 + 90,000 C 
 (ii) Hypsr-eutectoid steels (carbon over 0.834%) 
 
 T. S. = 142,000 20,600 C 
 (6) Elongation, percent in 2", for hypo-eutectoid steels: 
 
 E = 40 - 36 C 
 Thurston's formula for tensile strength (minimum values): 
 
 Unannealed steel: T. S. = 42.32 + 49.37 C 
 Annealed steel: T. S. = 35.27 + 42.32 C 
 
 T. S. in kilograms per square millimeter; carbon in percent. 
 
 Webster's formula for tensile strength, based on his values for 
 pure iron, carbon, phosphorus and sulphur, may be stated as 
 follows : 
 
 T. S. = 34,750 + 80,000 C + m P + 50,000 S 
 
 T. S. in pounds per square inch; C, P, and S in percent; m a 
 
 variable, depending on the carbon content, from 80,000 to 
 
 150,000. A former value assigned for pure iron was 38,000. 
 
 Weyrauch's formula for tensile strength (minimum values): 
 
 T. S. = 44-17(1 + C)j 
 
 T. S. in kilograms per square millimeter; C = percentage of 
 carbon. 
 
 (2) Structural Formulae. Sauveur's formulae: These are 
 based on the assumption that the tensile strength in pounds per 
 square inch is for ferrite 50,000, for pearlite 125,000, and for 
 cementite 5000; the percentage of elongation in 2" for ferrite 
 40, and for pearlite 10 (no estimate for cementite) : 
 (a) Tensile strength: 
 
 (i) Hypo-eutectoid steels : 
 
 T. S. = 500 F + 1250 P 
 = 50,000 + 750 P 
 
 () Hyper-eutectoid steels : 
 
 T. S. = 1250 P 4- 50 Cm 
 = 5000 + 1 200 P 
 
340 PHYSICAL PROPERTIES 
 
 (&) Elongation, percent in 2", for hypo-eutectoid steels: 
 
 E = 0.4 F + o.iP 
 = 40 - 0.3 P 
 
 F, P, and Cm = respective percentages of ferrite, pearlite, and 
 cementite. 
 
 Quality Formulae. These are for the purpose of comparing the 
 properties of a specimen with a standard, or of two or more 
 specimens with each other to decide their relative merits. To 
 illustrate why this is sometimes desirable, a piece of steel may be 
 likened to a photographic plate. The plate is capable of pro- 
 ducing a beautiful result provided it is suitably prepared, properly 
 exposed and carefully developed; a mistake in any one of these 
 processes will result in a defective negative. In the same way, 
 the steel if of suitable composition has latent possibilities which 
 can only be brought out to their fullest extent by the greatest 
 attention to every detail in its handling and treatment. Ex- 
 amples of how this works out will be given below. The figure 
 used for the comparison is termed the figure of merit, merit 
 number or quality figure. The formulae are based on the well- 
 known fact that, under the same general conditions, as the 
 strength increases the ductility decreases, and vice versa; and 
 while the assumption that they are inversely proportional is only 
 approximately true, and for limited ranges, the deductions which 
 may be drawn from it are sufficiently accurate for most purposes. 
 The specimen showing the largest quality figure must possess the 
 highest combination of strength and ductility and therefore 
 be in the highest state of development, at least from an abstract 
 viewpoint. There must, however, always be considered the 
 purpose for which the material is intended. Thus, a sample 
 with very high strength and comparatively low ductility might 
 have a higher quality figure than another sample with much lower 
 strength but higher ductility. For cold bending or flanging, 
 the second would be the more suitable. Where the determi- 
 nations are accurately made, the value for the elastic limit 
 best represents the strength; with turned specimens the reduc- 
 tion of area is a more accurate measure of the ductility than 
 the elongation which is more likely to be affected by the point of 
 rupture and the shape of the specimen. 
 
 De Marre formula: (see Armor Plate, page 8). 
 
 British or English formula : 
 
 M = T + E 
 
 M = figure of merit; T = tensile strength in gross tons per 
 square inch; E = elongation, percent, for specimens of iden- 
 tical or similar shape. 
 McKenna's formula : 
 
 M = T (E + 20) 
 
 M = figure of merit; T = tensile strength in pounds per 
 square inch; E = elongation, percent, for specimens of identical 
 or similar shape. 
 
PHYSICAL SOLUTION PICKLING 
 
 341 
 
 Tiemann's formula : 
 
 S X D 
 
 Q = quality figure; S = strength, either tensile strength, but 
 preferably elastic limit in any unit; D = ductility, either elonga- 
 tion, but preferably reduction of area, percent, for identical or 
 similar specimens. As examples of the last formula, taking the 
 elastic limit as S and the reduction of area as D: 
 
 No. 
 
 Treatment 
 
 Tensile 
 Strength 
 
 Elastic 
 Limit 
 
 Elonga- 
 tion, % 
 
 Reduc- 
 tion of 
 area, % 
 
 Quality 
 Figure 
 
 (E.L.XRed.) 
 
 i 
 
 2 
 3 
 
 4 
 
 5 
 
 Untreated 
 Untreated 
 Annealed 
 Quenched and Tem- 
 pered (a) 
 Quenched and Tem- 
 pered (6) 
 
 80,000 
 85,000 
 80,000 
 
 90,000 
 
 100,000 
 
 40,000 
 42,000 
 39,000 
 
 55,000 
 60,000 
 
 23 
 
 21 
 25 
 
 26 
 23 
 
 40 
 36 
 
 43 
 
 55 
 50 
 
 1,600,000 
 1,512,000 
 1,677,000 
 
 3,025,000 
 3,000,000 
 
 Nos. i and 2 are taken as samples of slightly different compo- 
 sition but having had the same treatment; Nos. 3 to 5, samples of 
 the same composition but having had treatment as shown. 
 , Obstruction Theory (Howe, Metallography, 389). "The 
 usual explanation of the increase of the tensile strength and 
 elastic limit with the carbon content is, briefly, that the stronger 
 pearlite stiffens the mass by impeding the flow of the weaker 
 ferrite; and, going a step further, that the reason why pearlite, 
 though made up of about 6 parts of ferrite to i of cementite, is 
 yet so much stronger than pure ferrite, is that this pearlitic 
 cementite thus stiffens the pearlitic ferrite. The pearlite in one 
 case and the pearlitic cementite in the other, is said to "hold up" 
 the ferrite. After discussing the "obstruction principle" I call 
 attention to the ferrite-refinement principle, that the effects of 
 increasing carbon contents may be due in considerable part to 
 the accompanying changes in the grain size of the ferrite." See 
 also Conduction (under Heat), page 200; Density, page 132; Ex- 
 pansion (under Heat), page 204. 
 
 Physical Solution. See page 107. 
 
 Physical Test. See page 467. 
 
 Physically Developed. A term sometimes applied to material 
 whose properties have been increased by cold working (e.g., cold 
 twisted bars) as opposed to heat treating. 
 
 Physically Dissolved. See page 107. 
 
 Physico-metallurgical (adj.). Relating to physical metallurgy, 
 q.v. 
 
 Piano Wire Gage. See page 187. 
 
 Pickling. The treatment of iron or steel with dilute acids for the 
 purpose of obtaining a clean surface by removing the scale 
 (oxide). When the action is completed the piece is washed in 
 water (swilled) to free it from the adhering acid, and is sometimes 
 
342 PICKLING BATH PIG IRON 
 
 dipped into milk of lime (liming) to eliminate the last traces. 
 The pickling fluid, when so exhausted that it can no longer be 
 used profitably, is known as spent acid or waste liquor. In 
 Reed's pickling process a solution of dilute sulphuric acid is used 
 and the object to be pickled is made the cathode, the anode 
 being a piece of lead. Pickling is of special application in the 
 manufacture of sheets and tin plate (page 431), tubes (page 491), 
 and wire (page 507). 
 
 Pickling Bath. See page 507. 
 
 Picric Acid. See page 287. 
 
 Piece. The particular piece of metal under consideration, usually 
 in connection with rolling or forging: see page 407. 
 
 Pielsticker and Miiller Process. See page 65. 
 
 Piercing. Producing a hole in a body by forcing a pointed instru- 
 ment through it, the displaced material being forced into the wall 
 (distinction from punching). 
 
 Pietzke Process. See page 380. 
 
 Pizeoglyps. See page 293. 
 
 Piezometer. See page 476. 
 
 Pig. (i) See Pig Iron; (2) in the open hearth process: see page 314. 
 
 Pig Back. See page 314. 
 
 Pig Bed. See page 36. 
 
 Pig Boiling. See page 374. 
 
 Pig Breaker. A machine for breaking off the pigs from the sow or 
 runner in the case of sand-cast pig iron. 
 
 Pig Casting Machine. See Pig Machine. 
 
 Pig Face. See page 68. 
 
 Pig Iron. Sometimes called pig metal : (i) the name given to cast 
 iron which is cast at the blast furnace into shapes known as pigs 
 for convenience in handling and transporting after cooling; 
 (2) also applied as a general term to the product of the blast 
 furnace (either solid or molten) before treatment in some refining 
 process, or casting into finished products. The name pig is 
 derived from the old method of casting when the molten metal 
 was led to the depressions or molds in the sand floor of the pig 
 beds; the iron in the molds proper, being connected to that in the 
 runner or feeder, bore a supposed resemblance to a litter of 
 sucking pigs, the runner being called the sow (sow metal). 
 This method produces what is known as sand cast pig. To 
 avoid the sand which always adheres, the iron is frequently cast 
 in metal molds or chills, and is then known as chill cast pig, or if a 
 pig machine is used, machine cast pig, or rarely, from the fact 
 that they are cast individually without a central connecting 
 runner, motherless pigs. 
 
 The color of the fracture of pig iron depends upon the con- 
 dition of the carbon; if it is all combined (the silicon being low) 
 the fracture is white (not silvery); if all is in the form of graphite 
 it is gray or graphitic (rarely called black) ; while if only a small 
 part is in the graphitic form, giving rise to alternate white and 
 gray spots, the iron is said to be mottled. Johnson has called 
 attention to spotted iron which is gray on the outside and has 
 white spots near the center; this he explains as due to silicon 
 
PIG IRON 343 
 
 below 0.8%, together with sufficiently rapid cooling, the portion 
 freezing last at the center being composed of the eutectic segre- 
 gate (Met, & Chem. Eng., Nov. i, 1916). If the silicon is high 
 the fracture is silvery (not white). Close pig (close grained 
 pig; close iron) has a very fine grained fracture; open iron has a 
 coarse fracture or grain-. Blazed pig, glazed pig, or glazy pig 
 (Eng.) is a grade which is brittle from high silicon. Cinder iron 
 or pig (Eng.) is smelted from a mixture containing some puddle 
 cinder or refinery cinder; According to T. Turner, a grade with 
 about 2^% carbon, i/^% manganese, and considerable phos- 
 phorus is common in South Staffordshire. Dry Iron (Eng.) is low 
 in silicon, while rich iron (Eng.) or hot iron is high in silicon and 
 usually low in sulphur. In foundry work iron which is fluid, 
 partly from its temperature and partly from its composition, is 
 called hot iron; the opposite is cold or dull iron or metal. Pig 
 iron suitable for making pots or similar objects is sometimes 
 called pot metal. Gun metal may signify either a kind of bronze, 
 or steel or cast iron suitable for making cannon. In the last case 
 (gun iron) requirements have been given as tensile strength 
 33,000 to 35,000 pounds per square inch, with transverse strength 
 of 4000 pounds on an arbitration bar i^" in diameter, with 12" 
 between supports. Pig steel (Richards, Eng. Soc. W. Pa., March 
 19, 1912) is the name for the metal made directly from iron ore in 
 an electric pig iron furnace, which is really crude steel with 2.2% 
 or less carbon, a very small amount of silicon and manganese, low 
 in sulphur and phosphorus. 
 
 Pig iron is classified according to (a) the method of manu- 
 facture (see Blast Furnace); (b) the purpose for which it is 
 intended; and (c) its composition. It was formerly graded by 
 breaking the pig and examining the fracture, but this method 
 has been largely superseded by chemical analysis. The terms 
 pig and iron are often used as abbreviations for pig iron, the 
 latter where the context indicates clearly what is meant. 
 
 A. Method of manufacture : 
 
 1. Coke pig: smelted with coke, and always with hot 
 
 blast. 
 
 2. Charcoal pig: smelted with charcoal: 
 
 (a) Hot blast. 
 
 (b) Cold blast. 
 
 3. Anthracite pig: smelted with anthracite coal mixed 
 with coke, and with hot blast. 
 
 B. Purpose for which intended: 
 
 4. Bessemer pig: for the Bessemer process: 
 
 (a) Acid (in this country the only kind) ; hematite 
 pig (Eng.) ; also used for the acid open hearth 
 process. 
 
 (b) Basic (foreign); Thomas pig: Thomas-Gil - 
 christ pig (Eng.). 
 
 5. Basic pig (basic open hearth pig) for the basic 
 
 process (U. S.), and for the basic Bessemer process 
 (foreign). 
 
344 PIG IRON 
 
 6. Malleable pig, or malleable, for malleable cast-iron 
 castings. 
 
 7. Foundry pig, for foundry work. 
 
 8. Forge pig: an inferior grade used for puddling and 
 for some classes of foundry work. 
 
 C. Chemical composition : 
 
 9. Silicon pig or high silicon pig. 
 
 10. Low phosphorus pig. 
 
 11. Special low phosphorus pig. 
 
 12. Ferro-alloys and special cast irons (e.g., ferro- 
 manganese) : see below. 
 
 The classification on the next page has been arranged by Eliot 
 A. Kebler based on the Government's scale of prices (to July i, 
 1918). The previous classification furnished by Mr. Kebler has 
 been retained also for purposes of reference: 
 
 (The following details have been taken largely from an article 
 by Eliot A. Kebler, of which the foreign classification was 
 supplied by W. W. Hearne, in the Iron Trade Review, June 25, 
 1908, entitled "Grading Pig Iron, Ferro-Alloys and Coke." 
 This has been somewhat rearranged and several additions 
 made.) 
 
 In this country pig iron is usually sold per ton of 2240 pounds 
 (rarely 2268 pounds), and always in England; in Germany and 
 France per metric ton of 1000 kilograms. 
 
 Bessemer pig iron : 
 
 Standard Bessemer (U. S.), used in making acid Bessemer 
 and acid open hearth steel. The standard specification is : 
 
 Silicon i to 2 . oo % 
 
 Phosphorus, not over o.oi 
 
 Sulphur, not over o . 05 
 
 In the central section (Mahoning and Shenango Valleys and 
 Pittsburg) it is sold per ton, 2268 pounds, if sand cast, or 2240 
 pounds, if chill cast, except for special purposes where the sand 
 iron is broken, in which case it may be sold per ton, 2240 pounds, 
 and a charge of 25c. may be added for breaking. In the East 
 and West (Chicago) it is always sold per ton of 2240 pounds. 
 
 Hematite, also spelled (Eng.) haematite (for acid Bessemer 
 process) : 
 
 Silicon, about 2 . 50 % 
 
 Sulphur, about o . 035 
 
 Phosphorus, usually -3S 
 
 seldom running over 0.06 
 
 West Coast hematite has manganese under 0.50%; East Coast 
 hematite, over 0.75%. Bessemer pig in Europe generally 
 should not contain more than 0.05% phosphorus. It is often 
 used as a synonym for hematite pig, but while the latter term 
 covers all the grades from No. i to white, the term Bessemer 
 pig is applied only to Nos. i, 2, and 3 (Ridsdale). This grade of 
 pig is also referred to as non-phosphoric. 
 
PIG IRON 
 
 345 
 
 11 
 
 o w ^-^ 
 
 "IP 
 
 B a 
 
 sfpl 
 
 cor* 3 
 
 !?U 
 
 
 7 i +++ i +++++ 
 
 3 . . "' "' - 
 
 CHARCOAL, 
 
 Southern or Warm Blast +$17 .00 
 Sil 2.00 max. P. 0.40-0.60. 
 Add $1.00 for each 0.50 additional Silicon. 
 Cold Blast +$47.00 
 Muirkirk + 37 .00 
 Northern Semi-cold Blast + 37 .00 
 Lake Superior for Sil. 1.25 max. + 2.50 
 
 Compiled by ELIOT A. KEBLER. 
 
 * 
 
 '. g 
 
 : 8. . 
 
 
 CO 
 
 
 
 ;W : : 
 
 : W ^M 
 
 :< :g 
 
 FOUNDRY IRON (All Sulphur under 0.05) 
 
 Manganese, % 
 
 foiS B c cs^2 8 d"o 6 c 
 
 LOW PHOSPHORUS. 
 Silicon not over 2.00. Sulphur not over 0.04. 
 
 o 
 
 ooooooooooo 
 
 OwtOOOOO^^OCI 
 
 :or each i % addition of Silicon. 
 
 Coppe 
 over o 
 
 O 00 t- v> fO i-i OiO *f) if) M 
 
 4* 
 
 
 
 n 
 
 o 
 
 o/-. oooooo 
 
 If 
 
 O 
 10 
 
 
 
 I-i O\OO i PO i-i O\ V O "5 IO H 
 M* 
 
 
 
 
 
 M 
 
 o o />o o o o o o 
 
 H 
 
 |a 
 
 O 
 fl 
 
 JOirtOOOOOO 
 O>O rfN Oi\O V)\f)n 
 
 ?+++++++! 
 
 M 
 
 O 
 1/J 
 
 o 
 
 M 
 
 SS^SSS , , , 
 
 3| 
 
 
 
 
 
 f<5 w 
 
 M M 
 ++- 
 
 ooooooooo 
 
 f-H-++++++ 
 
 V) 
 
 O M cOfJO t-CX) Oi 
 
 TI 
 
 s 
 
 O lOOOOOOO 
 T HjMOOOOOO 
 
 S H r<i uio r-^oo a 
 
 a 
 
 r 
 
 
 O O O O " O O 2 
 
 ooooooooooo 
 
 
 
 SILVERY 
 
 O 
 O /5 tOO 
 
 i-i roiAoo 
 
 000 
 O POO 
 
 'Z 
 
 0,0 ^^ 
 WM +++ 
 
 Add $3. oo for each 
 additional unit of Silicon. 
 
 I ! ! '. '.'.'.'. 
 
 . . . . . . . . 
 
 +++4-+ 
 
 d 
 
 8 
 
 CO 
 
 
 ^u, ,* ,0^.00 
 
 8 
 
 O 1^-00 O O 
 
 Wco 
 
 %z 
 %% 
 
 w 
 
 fe 22 
 
 O \f.ir>tf. if) if. if) if> tf. 
 
 HHNN ^ fOTrTtl 
 
346 PIG IRON 
 
 Thomas-Gilchrist or Thomas pig iron (for the basic Bessemer 
 process) is usually about : 
 
 Silicon 0.50% 
 
 Phosphorus 2 . 50 
 
 Manganese 2 . 50 
 
 Sulphur, up to 0.20 
 
 In England and on the Continent basic pig (phosphoric or 
 phosphoretic pig) is regarded as containing 1.5 to 3% phos- 
 phorus, 0.10% or less sulphur, 1.5 to 2.5% manganese, and less 
 than i% silicon (Ridsdale). 
 
 Malleable Bessemer or malleable iron (also called coke 
 malleable or malleable coke iron), used for the manufacture 
 of malleable cast-iron castings: the usual specification is: 
 
 Phosphorus, not over o. 20% 
 
 Sulphur, not over o . 05 
 
 Silicon, as specified o . 75 to 2 . oo 
 
 If sand cast, pigs are usually broken, and both sand cast and 
 chill cast are sold per ton of 2240 pounds, except from a few 
 furnaces in the Central District which still sell some broken 
 and unbroken pigs per ton of 2268 pouuds. 
 
 Low phosphorus pig (U. S.), sometimes called special low 
 phos (for making steel extra low in phosphorus): the usual 
 specification is : 
 
 Silicon i to 2 . 00% 
 
 Phosphorus, not over 0.035 
 
 Sulphur, not over 0.035 
 
 Higher silicon is desired when for use in baby Bessemer con- 
 verters. 
 
 Washed metal (see page 383) is pig iron from which most 
 of the silicon and phosphorus have been removed (for special 
 low phosphorus steel: open hearth and crucible process); it 
 is sold by analysis, the four analyses recognized (U. S.) being: 
 
 1. Phosphorus, not over 0.010% 
 
 Sulphur, not over 0.015 
 
 2. Phosphorus, not over 0.015 
 
 Sulphur, not over o . 020 
 
 3. Phosphorus, not over 0.020 
 
 Sulphur, not over 0.025 
 
 4. Phosphorus, not over 0.025 
 
 Sulphur, not over o . 030 
 
 It is cast on an iron plate, and comes in irregular pieces about 
 8" square; sold per ton of 2240 pounds. 
 
 Basic pig; basic iron (U. S.), for the basic open hearth 
 process; the specifications are: 
 
 Silicon, under i . oo 
 
 Sulphur, under 0.05 
 
 The phosphorus is not specified but is usually under 0.50%, 
 
PIG IRON 347 
 
 except with some Southern irons, when it may go as high as 
 1.00%. It is sold per ton of 2 240 pounds. In Europe or England 
 there is practically no open hearth basic pig made; at Middles- 
 boro, Bell Bros, are making a grade which analyzes: 
 
 Silicon 0.75 to 1.50% 
 
 Phosphorus i . oo to i . 75 
 
 Sulphur, up to o . 20 
 
 American foundry iron : graded by fracture (this method is 
 being rapidly superseded by analysis grading) : 
 
 No. i Foundry : Fracture contains crystals. 
 
 No. 2 Foundry : This is considered the standard and contains 
 medium-size crystals, say %" square, with no spot larger than 
 i" in diameter without crystals, although the pig can be close 
 for }/' along the edges. 
 
 No. 3 Foundry: Contains small crystals; fracture close. 
 
 East of Altoona, Pa., and throughout all of New York these 
 grades are No. i X, No. 2 X, No. 2 Plain, and No. 3 Foundry. 
 No. i is the highest in price, the usual differential being 50 
 cents a ton. 
 
 Forge has a gray fracture with practically no crystals. 
 
 Mottled shows small white spots giving the fracture a mottled 
 appearance; most of the carbon is in the combined state. 
 
 White shows a white fracture as practically all the carbon 
 is in the combined state. These last two grades are usually 
 high in sulphur and low in silicon. 
 
 In the South (U. S.) iron which has a silvery fracture is graded 
 as follows: 
 
 Silvery iron or silvery gray iron is sometimes divided into: 
 No. i Silvery, usually about 5 % of silicon. 
 No. 2 Silvery, usually about 4% of silicon. 
 
 No. i Soft : Solid same price as No. i Foundry. 
 
 No. 2 Soft: Solid same price as No. 2 Foundry. 
 
 No. 4 Foundry: Price is between that of No. 3 Foundry and 
 Gray Forge. 
 
 Foundry iron containing 6 to 12% of silicon is called high 
 silicon softener or softener, or is designated by the content, 
 e-g-, "8% silicon," etc. 
 
 Foundry pigs cast in sand are always broken, and the product 
 of all furnaces outside of a few in the Central District is sold 
 per ton of 2240 pounds. These few still sell per ton of 2268 
 pounds, the extra 28 pounds, being added to cover sand adhering 
 to the pig. Forge, mottled, and white irons may be broken 
 or unbroken and are sold per ton of 2240 pounds, with the excep- 
 tion of some Central District irons which are sold per ton of 
 2268 pounds. No. 2 Foundry and No. 2 X Foundry are the stand- 
 ards, and No. 2 Soft sells at the same price. No. i Foundry 
 or No. i Soft sells usually for 50 cents a ton higher, depending 
 upon the silicon content. The other grades decrease 25 to 
 50 cents a grade. Scotch indicates a more fluid iron, usually 
 higher in phosphorus and silicon than the ordinary furnace 
 run: the higher the silicon the higher the price. In selling by 
 
PIG IRON 
 
 analysis the tendency is to do away with numbers and merely 
 give the limits in silicon and sulphur. 
 
 American Foundry and Forge Iron Graded by Analysis: A 
 committee appointed by the blast furnace interests has made 
 the following classification by analysis, and the tendency is 
 to sell iron by analysis instead of by fracture. All pig iron 
 cast in chills is sold by analysis, per ton of 2240 pounds. 
 
 SOUTHERN POINTS 
 
 Silicon, % Sulphur, % 
 
 No. i Foundry 2 . 75 to 3 . 25 o . 05 and under 
 
 No. 2 Foundry 2 . 25 to 2 . 75 o . 05 and under 
 
 No. 3 Foundry i . 75 to 2 . 25 o . 06 and under 
 
 No. 4 Foundry i . 25 to 2 . oo o . 065 and under 
 
 Gray Forge i . 25 to i . 75 0.07 and up 
 
 No. i Soft 3 . oo and over o . 05 and under 
 
 No. 2 Soft 2 . 50 to 3 . 25 o . 05 and under 
 
 EASTERN POINTS 
 
 Silicon, % Sulphur, % 
 
 No. i X 2.75 and up o . 03 and under 
 
 No. 2 X Foundry 2 . 25 to 2. 75 0-045 and under 
 
 No. 2 Plain i . 75 to 2 . 25 o . 05 and under 
 
 No. 3 Foundry i . 25 to i . 75 o . 065 and under 
 
 No. 2 Mill 1.25 and under o . 065 and under 
 
 Gray Forge i . 50 and under 0.065 and up 
 
 NOTE. If sulphur is in excess of maximum, the iron is graded 
 as lower grade, regardless of silicon. 
 
 CENTRAL WEST AND LAKE POINTS 
 
 Silicon, % Sulphur, % 
 
 No. i Foundry 2 . 25 to 2 . 75 0.05 and under 
 
 No. 2 Foundry i . 75 to 2 . 25 o .05 and under 
 
 No. 3 Foundry 1.75 and under -o . 05 and under 
 
 Gray Forge o . 05 and over 
 
 BUFFALO DISTRICT 
 
 Silicon, % Sulphur, % 
 
 Scotch 3 oo and over 0.05 and under 
 
 No. i X 2 . 50 to 3 . oo o . 05 and under 
 
 No. 2 X 2 . oo to 2 . 50 o . 05 and under 
 
 No. 2 Plain i . 50 to 2 . oo o . 05 and under 
 
 No. 3 Foundry i . 50 (under) 0.05 and under 
 
 Gray Forge o . 05 (over) 
 
PIG IRON 349 
 
 CHICAGO POINTS 
 
 Silicon, % Sulphur, % 
 
 No. i Foundry 2 . 25 to 2 . 50 o . 02 to o . 05 
 
 No. 2 Foundry 1.75102.25 0.02100.05 
 
 No. 3 Foundry i .35 to i . 75 0.06 and under 
 
 Scotch 2 . 50 to 3 . oo o . 05 and under 
 
 Silvery 3 .00 to 3 . 50 0.05 and under 
 
 Gray Forge o . 06 and over 
 
 Sampling. The American Society for Testing Materials 
 recommended the following method of sampling which has 
 been adopted by the American Foundrymen's Association. 
 In all contracts where pig iron is sold by chemical analysis 
 each carload or its equivalent shall be considered as a unit. 
 At least one pig shall be selected at random from each four 
 tons of every carload, and so as fairly to represent it. Drill- 
 ings shall be taken so as fairly to represent the fracture surface 
 of each pig and the sample analyzed shall consist of an equal 
 quantity of drillings from each pig, well mixed and ground 
 before analysis. In case of disagreement between buyer and 
 seller, an independent analyst, to be mutually ^ agreed upon, 
 shall be engaged to sample and analyze the iron. In this 
 event each pig shall be taken to represent every two tons. 
 The cost of this sampling and analysis shall be borne by the 
 buyer if the shipment is proved up to specification, and by 
 the seller if otherwise. 
 
 English Foundry Iron. This is graded by fracture, and no 
 analysis is guaranteed. The rules for standard foundry pig 
 iron issued by the London Metal Exchange are as follows, and 
 it will be noted that, instead of grading by silicon content, as 
 in this country, sulphur seems to be the governing element: 
 
 Silicon, % Phosphorus, % Sulphur, % 
 
 No. i 2> to 3^ i. oo 0.04 
 
 No. 2 2^ to 3^ 1.25 0.05 
 
 No. 3 i not over 3)^ 1.65 0.08 
 
 No. 4 i not over 3 i . 75 o. 10 
 
 The ordinary English pig irons can be divided into two groups, 
 with 
 
 Manganese, under 0.75%, and 
 Manganese, say, 0.75 to 1.10%. 
 
 The brand and grade chiefly imported into this country is 
 Middlesboro No. 3 ; analysis unguaranteed, but usually 
 
 Phosphorus i . 40 to i . 50% 
 
 Manganese 0.40 to 0.75 
 
 Silicon, usually high, say 2 . 50 
 
 Sulphur , o . 02 to o . 05 
 
 No. i has practically the same composition except that the 
 sulphur is extremely low. 
 
350 PIG IRON 
 
 All mine pig, mine pig, or ore metal (Eng.) is made from ore 
 without any admixture of scale or cinder; its composition is 
 about as follows : 
 
 Phosphorus o. 20 to o. 70% 
 
 Sulphur o . 06 to o . 20 
 
 Manganese, under o. 75 
 
 Scotch iron is also sold by fracture, a typical analysis of 
 No. 3 being: 
 
 Phosphorus 0.60 to 1.15% 
 
 Manganese. i . 10 to i . 80 
 
 Sulphur, about o . 03 
 
 Silicon, about 2 .00 to 2 . 50 
 
 American Charcoal Irons. These irons are divided into 
 two classes: 
 
 (a) Cold blast, which is made in small furnaces with a 
 capacity of about 4 to 8 tons a day, blown with un- 
 heated air, and 
 
 (&) Warm blast, in which the blast is preheated to from 
 500 to 900 F. (260 to 480 C.). 
 
 Cold blast charcoal iron (used principally for making 
 chilled rolls), outside of the Lake Superior region, is graded as 
 follows: 
 
 No. i, highest silicon, lowest sulphur iron, with a fracture 
 like that of a No. 3 coke iron. 
 
 No. 2 has a fracture like that of a Forge, and will chill %" deep 
 when cast against an iron plate. Casting such an iron on an iron 
 plate to determine the depth of chill is called the chill test. What 
 is termed a paper chill is where a line of white no thicker than a 
 piece of paper is visible around the edge of the pig (Johnson). 
 
 No. 3 shows Y' chill. 
 
 No. 4 a %" to K" chill. 
 
 No. 5 a %" to i%" chill, the face of the pig being strongly 
 mottled. 
 
 No. 6 is white, practically all of the carbon being in the com- 
 bined state. 
 
 Warm blast or hot blast charcoal iron (used principally for 
 car-wheel work, for strengthening general machinery castings, 
 and for making rolls), outside of the Lake Superior region, is 
 graded as follows: 
 
 No. i, highest silicon, lowest sulphur iron, with a fracture 
 like that of No. 2 coke iron. 
 
 No. 2 has a fracture like that of a No. 3 coke iron. 
 
 No. 3 has a fracture similar to that of Forge. 
 
 No. 4 will show a chill about K" deep if cast against an iron 
 plate. 
 
 No. 5, a chill about M" to %". 
 
 No. 6,,a chill of about %" to iK", and is mottled when cast in 
 sand. 
 
 No. 7 has a white fracture; the carbon is practically all com- 
 bined. 
 
PIG IRON 
 
 351 
 
 Lake Superior charcoal irons are graded, not by fracture, 
 but by analysis, the following classification being most gener- 
 ally used: 
 
 
 SILICON, % 
 
 
 Average 
 
 Min. 
 
 Max. 
 
 Chill 
 
 A Scotch 
 
 2.50 
 
 2.38 
 
 2.62 
 
 
 B Scotch 
 
 ...... 2.25 
 
 2.13 
 
 2-37 
 
 
 C Scotch 
 
 2 OO 
 
 1.88 
 
 2.12 
 
 
 Low i 
 
 I .7C 
 
 1.63 
 
 1.87 
 
 
 High i 
 
 *:* f V 
 
 I .50 
 
 1.38 
 
 1.62 
 
 
 Low 2 
 
 I . 25 
 
 i . 13 
 
 1,37 
 
 
 High 2 
 
 I . OO 
 
 0.88 
 
 I . 12 
 
 
 T 
 Low 3 
 
 07=; 
 
 o 63 
 
 0.87 
 
 Trace to y' 
 
 High * 
 
 o ^6 
 
 w W O 
 
 O. tJO 
 
 o. 62 
 
 VA" tO %" 
 
 Low 4 
 
 o . 44 
 
 v O v 
 
 0.38 
 
 0.50 
 
 %" to i" 
 
 High 4 
 
 0.32 
 
 0.25 
 
 0.38 
 
 i "to iH" 
 
 Low 5 
 
 o. 20 
 
 0-15 
 
 0.25 
 
 Low mottled 
 
 Highs 
 
 O. IO 
 
 0.05 
 
 0-15 
 
 White mottled 
 
 No. 6.., 
 
 o.oo 
 
 0.00 
 
 o.os 
 
 White 
 
 Phosphorus 
 
 Manganese 
 
 Sulphur 
 
 0.15 to 0.22% 
 o . 30 to o . 70 
 trace to 0.018 
 
 Ferro-alloys, ferro -products, special cast irons, or alloy cast 
 irons. These are alloys or metallic compounds of iron with a 
 considerable amount of some special element or elements (alloy 
 elements), such as manganese, chromium, etc., and contain, as a 
 rule, an equal or greater amount of carbon than ordinary pig 
 iron, this last differentiating them from special steels (?..), 
 although the dividing line is not always sharply drawn. Howe 
 suggests (E. & M. J., 1911) as definitions for ferro-alloy: "An 
 alloy of iron with so large a proportion of some element other 
 than carbon that it is not usefully malleable at any temperature." 
 or "Iron so rich in some element other than carbon that it is used 
 as a vehicle for introducing that element in the manufacture of 
 iron or steel." Tiemann has suggested that ordinary pig iron, as 
 the initial member of the ferro-alloy series, corresponding to 
 ferro-manganese, etc., be designated as ferro-carbon. Owing 
 to the fact that many of the ferro-alloys have been in use for only 
 a comparatively short time, fixed standards have not, in many 
 cases, been accepted. One company designates its material 
 by showing the number of units of carbon by "X," and the 
 kind of alloy by its chemical symbol; thus: a ferro-chrome con- 
 taining 9.70% of carbon would be designated "gXCr." All 
 foreign ferro-alloys are sold to the American consumers 'f.o.b. 
 cars American seaboard, based on existing duties, United States 
 Custom House weights at seaboard to govern settlement, and 
 certificate of foreign chemist of repute to be conclusive as to 
 quality. 
 
 Ferro-aluminumlis sold containing 10% aluminum. Metallic 
 
352 PIG IRON 
 
 aluminum comes in two grades: No. i being guaranteed over 
 99%, and No. 2, over 90% pure aluminum, with no impurities 
 rendering it unsuitable for alloying with iron or steel. Each 
 grade is sold by the pound. 
 
 Ferro-chrome, ferro-chromium, or chromeisen runs 60 to 
 68% of chromium. It is graded per unit of chromium and per 
 unit of carbon, the price increasing with the chromium, and 
 decreasing with the increase in carbon, the percentage of these 
 elements being guaranteed. If low in carbon it is sometimes 
 called mild ferro-chrome. It is sold per ton of 2240 pounds. A 
 typical analysis, guaranteed only as above, is as follows: 
 
 Mild, % Ordinary, % 
 
 Chromium 64.80 66.00 
 
 Iron 33-43 21.91 
 
 Carbon 1-21 9.90 
 
 Silicon o . 29 i . 40 
 
 Phosphorus 0.027 0.07 
 
 Sulphur 0.02 0.22 
 
 Manganese o . 09 o . 20 
 
 Copper 0.12 
 
 Aluminum .... 
 
 Eerro-chrome is manufactured in an electric furnace which may 
 be of several types, such as a Heroult or a Girod furnace as used 
 for making steel. The charge consists of chromite and anthra- 
 cite coal mixed in proportions based on theoretical calculations. 
 In one operation direct from ore, ferro-chrome with as low as 5 % 
 carbon can be made economically; and it is possible to produce it 
 with as little as 2%. The refining of high grade ferro-chrome 
 is carried on in an arc furnace, where the alloy is subjected to 
 prolonged heating with a slag of chromite, lime and flourspar. 
 In this way the carbon can be reduced from 10 to 0.25% but 
 more usually about 0.50%. The content of chrome remains 
 about the same, and the silicon may be reduced to about 0.2% 
 (Keeney, Am. Electroch. Soc., XXIV). 
 
 Ferro-manganese contains over 30%, usually over 60%, 
 manganese. Standard ferro-manganese is guaranteed only to 
 average 80% or over of manganese. The English grade runs 
 lower in phosphorus than that from the Continent. It is sold 
 per ton of 2240 pounds. A typical analysis, manganese only 
 guaranteed, is: 
 
 American, % 
 80.20 
 12. 18 
 0.66 
 o. 16 
 trace 
 6.80 
 
 I 
 
 Manganese 
 
 Inglish, % 
 80.50 
 
 Iron, by difference. . 
 Silicon 
 
 11.50 
 1.65 
 
 Phosphorus 
 Sulphur 
 
 0.23 
 
 Carbon. . 
 
 6.78 
 
PIG IRON 353 
 
 Ferro -molybdenum is sold per pound of pure molybdenum 
 contained, regardless of the percentage of other constituents. 
 Thus, if a pound of 80% ferro-molybdenum is purchased, i>^ 
 pounds of alloy will be received. A typical analysis, molybdenum 
 only guaranteed, is: 
 
 Molybdenum 79-5% 
 
 Iron 17-55 
 
 Carbon. 3 . 24 
 
 Phosphorus o . 028 
 
 Sulphur 0.021 
 
 It is generally manufactured in the electric furnace from raw 
 sulphide ore (molybdenite); also by reduction of the roasted 
 sulphide with carbon in a crucible or the electric furnace (Keeney). 
 Ferro-nickel is made with 25, 35, 50, or 75% of nickel as 
 specified. The percentage of the other constituents, exclusive 
 of the iron, is approximately: 
 
 Carbon o . 85 % 
 
 Silicon o. 25 
 
 Sulphur. o. 15 
 
 Phosphorus o . 025 
 
 Nickel, metallic nickel, or ingot nickel, as ordinarily used in 
 the manufacture of nickel steel, is guaranteed over 99% nickel, 
 and is sold by the pound. 
 
 Ferro-phosphorus contains over 10% of phosphorus. It is 
 sold per ton of 2240 pounds. The foreign is guaranteed 22 to 24%. 
 A typical analysis of the foreign product, phosphorus only 
 being guaranteed, is: 
 
 Phosphorus ~ 21 .40% 
 
 Iron .- 75-03 
 
 Manganese o. 70 
 
 Silicon i . 63 
 
 Carbon 1.17 
 
 The domestic is guaranteed: 
 
 Phosphorus 18 to 22 .00% 
 
 Sulphur, under. o . 05 
 
 Manganese, under o . 50 
 
 Pftospho -manganese is essentially a ferro-manganese con- 
 taining a high percentage of phosphorus. It is sold per ton of 
 2240 pounds. A typical analysis shows approximately: 
 
 Manganese 65 .00% 
 
 Phosphorus 25 . oo 
 
 Iron 7.00 
 
 Carbon 2.00 
 
 Silicon i . oo 
 
 23 
 
354 PIG IRON 
 
 Ferro-silicon, siliconeisen, or high silicon pig is used in the 
 manufacture of steel to increase the silicon. It is usually 
 called Bessemer ferro-silicon (sometimes ordinary fem>- 
 silicon) as the American is guaranteed not over 0.10% of phos- 
 phorus, and not over 0.05% of sulphur, and the foreign, while 
 not guaranteed, is approximately the same. The silicon is 
 10 to 20%, usually 12%, the price increasing about $1.00 a 
 ton per unit. It is sold per ton of 2240 pounds. A typical 
 analysis shows: 
 
 Silicon 12.74% 
 
 Phosphorus o . 095 
 
 Manganese 0.87 
 
 Sulphur 0.02 
 
 Ferro-silicon higher than this is produced in the electric furnace, 
 and ordinarily contains over 40% of silicon, and is known as 
 special ferro-silicon or special high silicon iron. It is guar- 
 anteed 50.% silicon, with a variation in price of $1.75 per unit 
 either way. The other constituents are not guaranteed. A 
 typical analysis shows: 
 
 Silicon 49 . 90% 
 
 Manganese 0.016 
 
 Carbon.- -S5 
 
 Phosphorus , 0.075 
 
 Sulphur 0.018 
 
 There is also a grade guaranteed to average 75% of silicon, 
 with a variation in price of $2.50 per unit either way. 
 
 Silico -Spiegel is a product of the blast furnace. It contains 
 17 to 22% of manganese and 6 to 12% of silicon. It is sold 
 per ton of 2240 pounds. The standard is guaranteed: 
 
 Manganese 18 to 20% 
 
 Silicon 9 to n, average 10% 
 
 A typical analysis, nothing but manganese and silicon guar- 
 anteed, shows: 
 
 Manganese "20.32% 
 
 Iron, by difference 68.02 
 
 Silicon 10 . 33 
 
 Carbon i . 26 
 
 Phosphorus 0.07 
 
 Sulphur 
 
 Silico-ferro-manganese or silico -manganese is the name usually 
 applied when higher in manganese: Manganese about 60 to 80%, 
 silicon, 20 to 25%, and varying percentages of carbon, iron, and 
 aluminum. There are three silicides of manganese recognized: 
 SiMn, SiaMns, and Si2Mn. 
 
 Silicon-calcium-aluminum has been tried as a deoxidizer; it is 
 reported to consist of approximately: 
 
 Silicon 47 to 57% 
 
 Calcium 15 to 25 
 
 Aluminum 2 . 5 to 6 . 5 
 
PIG IRON 355 
 
 Ferro-sodium is obtained by dissolving metallic sodium in 
 molten pig iron in a crucible. It is sold per pound, and usually 
 contains 25% of sodium, free from lime or excess of carbon. 
 
 Spiegel, spiegeleisen, mirror iron, or specular pig iron, is a prod- 
 uct of the blast furnace. It contains 10 to 30% of manganese. 
 It is sold per ton of 2240 pounds, and the standard is guaranteed: 
 
 Manganese 18 to 22%, average, 20% 
 
 Phosphorus, not over o. 10 
 
 The silicon limits are sometimes specified. A typical analysis, 
 guaranteed only as above, shows: 
 
 Manganese 20.50% 
 
 Iron 73 . 61 
 
 Silicon 0.76 
 
 Carbon 5.18 
 
 Sulphur. o . 002 
 
 Phosphorus o . 055 
 
 Ferro -titanium is produced in the blast furnace or, for higher 
 grades, in the electric furnace. The lower alloy contains 10 
 to 12%, is guaranteed only for titanium, and is sold per pound 
 of alloy. A typical analysis shows: 
 
 Titanium 11.21% 
 
 Iron, by difference 87 . 68 
 
 Carbon 0.67 
 
 Silicon 0.37 
 
 Phosphorus o . 04 
 
 Sulphur o . 03 
 
 If higher in titanium, it is sold per pound of pure titanium 
 contained, regardless of the percentage of other constituents, 
 the titanium alone being specified. A typical analysis shows: 
 
 Titanium 51 . 30 % 
 
 Iron 44.18 
 
 Carbon 2.82 
 
 Manganese o . 08 
 
 Arsenic 1.12 
 
 Sulphur o . 047 
 
 Phosphorus 0.021 
 
 Aluminum 0.41 
 
 Ferro -tungsten is sold per pound of tungsten contained, the 
 price increasing with the increase in tungsten, and decreasing 
 with the increase in carbon. Typical analyses, the tungsten 
 and carbon only being guaranteed, show: 
 
 Tungsten 85.47% 61.20% 
 
 Iron 13-90 33-02 
 
 Carbon o . 30 2.97 
 
 Silicon 0.13 0.47 
 
 Manganese o . 09 i . 88 
 
 Aluminum o.oo 0.31 
 
 Phosphorus 0.019 o . 03 
 
 Sulphur 0.025 0.03 
 
PIG IRON PINCH BAR 
 
 It is manufactured from ores in three ways: (i) by direct 
 reduction by carbon in a crucible; (2) by reduction in an electric 
 furnace by some reducing agent other than carbon; (3) by direct 
 reduction by carbon in an electric furnace (Keeney). 
 
 Ferro-vanadium is sold per pound per unit of vanadium 
 contained, i.e., if the alloy contains 20% of vanadium, . and 
 the selling price is 5C. per unit, it would cost $1.00 per pound, 
 of alloy. A typical analysis, vanadium alone being guaranteed, 
 shows : 
 
 Vanadium 36.00% 
 
 Manganese o . 60 
 
 Iron 61 .00 
 
 Carbon o . 40 
 
 Silicon 0.90 
 
 Aluminum o . 80 
 
 It may be produced by the thermit process; by reduction of the 
 oxide with carbon; or by reduction of vanadate of iron with 
 carbon in a crucible. In Europe some is made by the reduction 
 'of the oxide, sulphide, or vanadate of iron with carbon in an 
 electric furnace (Keeney). 
 
 Pig Iron, Sampling of. See page 349. 
 
 Pig Machine. An appliance for the continuous casting of pig 
 iron in iron molds. The types at present in use consist of one or 
 more endless strings or strands of molds mounted on vertically 
 revolving drums. The metal is run into the molds from a ladle 
 at one end, and is rapidly cooled with water as the molds advance, 
 so that the pigs are cold enough to be dumped into a car or other 
 receptacle when they reach the other end. In another type, 
 formerly used, the molds were mounted on a large horizontally 
 revolving table. 
 
 Pig Metal. See page 342. 
 
 Pig and Ore Process. (i) Crucible process: see page 113; (2) 
 open hearth process: see page 310. 
 
 Pig and Scrap Process. (i) Crucible process: see page 113; (2) 
 open hearth process: see page 310. 
 
 Pig Steel. See page 343. 
 
 Pig Up. See pages 314 and 393. 
 
 Pig Washing Processes. See page 383. 
 
 Pigging. In open hearth practice: see page 314. 
 
 Pigment. See 'page 365. 
 
 Pile. (i) A type of furnace: see page 181; (2) in connection with 
 puddling, etc.: see page 377. 
 
 Pilger Rolls. See page 490. 
 
 Pill Heat. See page 257. 
 
 Pillaring. See page 35. 
 
 Pin (Eng.). Housing screw: see page 403. 
 
 Pin Bottom. See page 17. 
 
 Pin Hole. See page 113. 
 
 Pinacoidal Cleavage. See page 124. 
 
 Pinch Bar. A crowbar; also a special form for moving cars by pry- 
 ing the wheels. 
 
PINCH PHENOMENON PITCH DIAMETER 357 
 
 Pinch Phenomenon. In electricity: see page 158. 
 
 Pinch Roll. See page 415. 
 
 Pinched Sheet ; Pincher. See page 430. 
 
 Pine Tree Crystal. See page 122. 
 
 Pinhead Blister. See Blister. 
 
 Pinion ; Pinion Housings. See page 407. 
 
 Pink Method. See page 61. 
 
 Pinny (Eng.). A term used to describe metal which contains 
 enclosed particles of metal harder than the rest. 
 
 Pintsch Gas. See Oil Gas. 
 
 Pipe; Piping. (i) A defect in castings: see page 53; (2) tubes: 
 see page 489. 
 
 Pipe Metal. An alloy of lead and tin used for making organ pipes. 
 
 Pipe Ore. See page 244. 
 
 Pipe Stove. See page 34. 
 
 Piping Steel. See page 55. 
 
 Pisolitic Ore. See page 244. 
 
 Pistol. For metal spraying: see page 373. 
 
 Pistol-Pipe Stove. See page 34. 
 
 Pit. A depression in the surface of material caused (a) by subcu- 
 taneous blowholes from which the skin has been burned away, 
 and (b) from scale or dirt rolled or forged in, and which has 
 subsequently dropped out. Where the skin from a blowhole has 
 not entirely burned away but is not welded to the rest of the 
 metal and may be removed by hammering the piece, it is called 
 a scab, shell or spill (Eng.), and the material is said to be scabby, 
 shelly or spilly. When this occurs in the tread of car wheels 
 (usually cast iron), i.e., when particles of -the metal drop out 
 leaving a hole resembling a carbuncle, it is known as shelling or 
 shelling out ; the flaking out of material in steel wheels is sometimes 
 similarly designated but more commonly as spalling or sometimes 
 scaling. A defect sometimes occurs in cast iron wheels which 
 have become worn through the chill, and have fine cracks present- 
 ing an appearance somewhat like that of a comb, hence such 
 wheels would be called comby. (2) An excavation to receive 
 cinder, or in which molds are placed. 
 
 Pit Annealing. See page 58. 
 
 Pit Casting. See page 57. 
 
 Pit Coal. See Coal. 
 
 Pit Healing Furnace. See page 184. 
 
 Pit Hole. See Pit. 
 
 Pit Sample. See page 82. 
 
 Pit Scrap. The steel which has run into the cinder pit under the 
 ladle when a heat is tapped. 
 
 Pitch. (i) The height of the top of an arch above the points from 
 which it springs; (2) the distance between two consecutive threads 
 of a screw measured on a line parallel to the axis, or, in other 
 words, the amount the screw would be raised by one complete 
 revolution; (3) a thick, sticky, black substance obtained from the 
 sap of pine trees, or by the distillation of coal. 
 Pitch Diameter; Line. The center line of a rolling mill; a line 
 parallel with the axis. 
 
358 PITTING POISSON'S RATIO 
 
 Pitting. See Pit; also page 106. 
 
 Plain Annealed Wire. See page 508. 
 
 Plain Drawn Wire. See page 508. 
 
 Plain Roll. See page 404. 
 
 Plaited Structure. See page 126. 
 
 Plane. (i) Of shear: see page 337; (2) of symmetry: see page 123; 
 (3) of weakness: see page 123. 
 
 Planished Sheet. See page 431. 
 
 Planishing Rolls. See page 415. 
 
 Plastic. See page 331. 
 
 Plastic Compression. See page 63. 
 
 Plastic Deformation. See pages 279 and 281. 
 
 Plastic Elongation. See page 472. 
 
 Plastic Material. See page 331. 
 
 Plastic Origin. Produced in a plastic condition. 
 
 Plastic Static Deformation. See page 281. 
 
 Plastic Strain. See page 334. 
 
 Plastic Sulphur. See Sulphur. 
 
 Plasticity. See page 331. 
 
 Plate. A flat piece of metal produced by rolling (rarely by ham- 
 mering), usually over No. 12 gage or }/%" thick; if thinner than 
 this it is generally called a sheet, except in the case of tin plate. 
 Plates for safes, armor plate, etc., are sometimes made by welding 
 together several plates of wrought iron or soft steel and high 
 carbon or alloy steel, alternately, which, according to the number 
 employed, are called three-ply, five-ply, etc. See also page 430. 
 
 Plate Iron; Metal. See page 383. 
 
 Plate Mill. See page 413. 
 
 Plate Molding. See page 300. 
 
 Plated Bars. See page 71. 
 
 Platen. See page 301. 
 
 Platines (obs.). An old name given to the material rolled into 
 
 sheet iron thinner than boiler plate. 
 Plating. Metallic coating for protection: see page 370. 
 Plating Forge ; Hammer. See Hammer. 
 Platinite. See page 451. 
 
 Platinum Resistance Pyrometer. See page 208. 
 Platinum Steels. See page 453. 
 Platt Process. See page 369. 
 Plessite. See page 291. 
 Plow Steel Wire. See page 509. 
 Plug. Of a converter: see page 17. 
 Plumbago Blacking. See page 298. 
 Plumbago Crucible. See page in. 
 Plus Gage. See page 186. 
 Ply. See Plate. 
 
 Pneumatic Molding Machine. See page 301. 
 Pneumatic Process (obs.). Bessemer processs: see page 15. 
 Poisoning (rare). Of metal, when some substance (usually intro- 
 duced in the process of manufacture) injures the quality. 
 Poikilitic Structure. See page 125. 
 Poisson's Ratio. See page 336. 
 
POLING POT MELTING 359 
 
 Poling. Stirring molten metal, either in a furnace or in a ladle, 
 with a pole of green wood, the heat distilling off the volatile 
 products which stir up the metal and, together with the char- 
 coal formed, help to reduce any oxides present. 
 
 Polish-Attack ; Polish -Etching. See page 288. 
 
 Polishing. See page 285. 
 
 Polyatomic. See page 87. 
 
 Polybasic. See page 87. 
 
 Polycellular Structure. See page 126. 
 
 Polycentric Structure. See page 126. 
 
 Polyhedral Steel. See page 443. 
 
 Polymerism. See page 85. 
 
 Polymorphic Transformation. See page 327. 
 
 Polymorphism; -ous. See page 121. 
 
 Polysomatic. See page 292. 
 
 Polysynthetic Twinning. See page 1 24. 
 
 Pommarede Method. See Iron. 
 
 Pond Sludge. See page 33. 
 
 Pbnsard Furnace ; Process. See page 144. 
 
 Pontelec Method. See page 503. 
 
 Pony Roughing Stand. See page 4*5- 
 
 Pool (rare). The hearth of a reverberatory or other furnace. 
 
 Poole Process. See page 73. 
 
 Poor Lime. See Flux. 
 
 Pop Mark (Eng.). See page 473- 
 
 Porcelanic Fracture. See page 178. 
 
 Porous. See page 55. 
 
 Poryphyritic Structure. See page 125. 
 
 Port. In a furnace (generally of the regenerative type), the open- 
 ings through which the air and gas enter, and the products of 
 combustion leave; the space over the hearth. 
 
 Porter ; Porter Bar. A long bar for handling heavy pieces of metal, 
 particularly for forging. It has a chuck at one end which fits 
 over, or is welded to, one end of the piece, and a counterweight 
 at the other end, and the whole is raised by a chain fastened at the 
 proper point to balance. 
 
 Porter Process. See page 371. 
 
 Portevin's Method. For etching: see page 287. 
 
 Posnikoff Process. See page 60. 
 
 Post-Eutectic. See page 269. 
 
 Post-Eutectoid. See page 271. 
 
 Post-Genital Malleableness. Not malleable as produced, but 
 made so subsequently. 
 
 Post-Neutral Period. In solidification: see page 54. 
 
 Pot. (i) A box used in annealing; (2) the box or chamber used 
 in the cementation process; (3) a crucible; (4) a ladle (obs.). 
 
 Pot Annealing. See page 232. 
 
 Pot Furnace. Crucible Furnace. 
 
 Pot Galvanizing. See pages 370 and 431. 
 
 Pot Hole. See page 114. 
 
 Pot House. See page 112. 
 
 Pot Melting. See page 113. 
 
360 POT METAL PRESS 
 
 Pot Metal. See page 118. 
 
 Pot Packer. See page 114. 
 
 Potash. (i) The element potassium, e.g., caustic potash (potassium 
 hydrate), etc.; (2) potassium carbonate. 
 
 Potash Hardening. See page 69. 
 
 Potassa. Potash. 
 
 Potassium. K.; at. wt., 39; melt, pt, 62.9 C. (145.2 F.); 
 sp. gr., 0.86. It is always found in the combined state with 
 oxygen, etc. As the oxide or the carbonate it finds a very 
 limited application as a flux, but practically never in the met- 
 allurgy of iron or steel, except accidentally. 
 
 Potential Brittleness. See Brittleness. 
 
 Potential Recrystallization. See page 216. 
 
 Potentiometer Method. For temperature measurements: see 
 page 208. 
 
 Pottering Down (Eng.). See page 114. 
 
 Pottery Mine. See page 244. 
 
 Pottkoff Process. See page 371. 
 
 Pouillet's Color Scale. Of temperatures: see page 210. 
 
 Pouillet Pyrometers. (i) Gas: see page 207; (2) pyrhelio meter: 
 see page 207. 
 
 Pound Calorie. See page 200. 
 
 Pound-Centigrade Heat Unit. See page 200. 
 
 Pouring. See pages 53 and 57. 
 
 Pouring Basin; Gate. See page 299. 
 
 Pouring, Special Methods of. See page 59. 
 
 Power. Of a microscope: see page 285. 
 
 Power Gas. See Producer. 
 
 Practical Proof Strain. See page 468. 
 
 Precipitate ; Precipitation. See page 88. 
 
 Precipitation Process. Of C. W. Siemens: see page 146. 
 
 Preliminary Slag. See Slag. 
 
 Preliminary Test. See Furnace Test. 
 
 Pre-Neutral Period. In solidification: see page 54. 
 
 Preparation of Specimens. For metallographic examination: see 
 page 285. 
 
 Prepared Iron. See page 364. 
 
 Preservative Coatings ; Process. See page 362. 
 
 Press. Or hydraulic press; a machine used for working metal, 
 much in the same way (except for special purposes) as with a 
 hammer, but as its effect penetrates throughout the piece, 
 its action being comparatively slow so that opportunity is 
 given for the metal to flow, it is available for larger pieces, 
 and also, as a rule, gives a much better sructure. It consists 
 essentially of a hydraulic cylinder in which a plunger or ram 
 moves vertically and which is forced down upon the piece of 
 metal suitably supported on an anvil block as in the case of 
 hammers, The action of the ram may be continuous (con- 
 tinuous acting press), i.e., the squeeze may be of the same 
 intensity throughout its duration, or it may be intermittent 
 or pulsating (intermittent acting press), increasing and decreasing 
 while the actual squeeze is taking place. 
 
PRESS HARDENING PRICKING 
 
 361 
 
 Press Hardening. See page 229. 
 
 Presser. That portion of a molding machine which imparts the 
 
 necessary pressure to the molding sand (Homer). 
 Pressing. See Forging. 
 Pressing-in Method. For determining hardness: see page 477. 
 
 FIG. 49. 10,000 ton hydraulic press. 
 
 Pressure Hardening. See page 229. 
 Prevost's Law. See page 200. 
 Price and Nicholson Process. See page 118. 
 Prick-punch Marks. See page 473. 
 Pricking. In wire drawing: see page 508. 
 
362 PRIMARY AUSTENITE PRODUCER 
 
 Primary Austenite. See page 274. 
 
 Primary Cementite. See page 273. 
 
 Primary Crystals. See page 121. 
 
 Primary Crystallization. See page 1 20. 
 
 Primary Furnace. See page 316. 
 
 Primary Gas. See page 33. 
 
 Primary Hardening. See page 447. 
 
 Primary Metals. See Secondary Metals. 
 
 Primary Slip. See page 283. 
 
 Primary Stress. See page 332. 
 
 Primaustenal, Primaustenoid. See page 275. 
 
 Primes. Of sheets: see page 433. 
 
 Priming Coat. See page 365. 
 
 Primitive Elastic Limit. See page 471. 
 
 Prince Process. See page 387. 
 
 Principal Stress. See page 332. 
 
 Prinsep Method. For temperature measurements: see page 209. 
 
 Print. See page 285. 
 
 Printing Methods of Etching. See page 288. 
 
 Prismatic Cleavage. See page 1 24. 
 
 Prismatic Structure. See page 125. 
 
 Prismatic Sulphur. See Sulphur. 
 
 Prismatic System. Of crystallization: see page 120. 
 
 Process Annealing. See page 509. 
 
 Process Metallurgy. See Physical Metallurgy. 
 
 Producer ; Producer Gas. Rarely called generator gas; this is a 
 fuel gas produced by blowing air through a thick bed of incan- 
 descent carbon (generally coal), the theoretical reaction giving a 
 composition by volume of 23% of carbon monoxide and 77% of 
 nitrogen. As ordinarily made, a certain amount of steam is 
 blown in with the air, the proportion being such that the tem- 
 perature of the bed of fuel is not unduly lowered. The advan- 
 tage from the use of steam consists in preventing the excessive 
 formation of clinkers by keeping the temperature from becom- 
 ing too high, and also by converting the extra specific heat 
 into latent heat in the reaction between the steam and the 
 carbon, this heat being recovered later when the gas is burned. 
 The gas made with steam is sometimes called mixed gas, being 
 a combination of straight producer gas and water gas, and the 
 process, mixed process; it is also known as semi-water gas, 
 Dowson gas (Eng.), or power gas. The composition by volume 
 of a good grade of gas from a modern producer using bituminous 
 coal and steam is about: 
 
 Carbon monoxide 26 % 
 
 Hydrogen 13 
 
 Hydrocarbons 4 
 
 Carbon dioxide 4 
 
 Nitrogen 53 
 
 The apparatus in which the gas is made is called a gas pro- 
 ducer or simply a producer, rarely a gas generating furnace 
 
PRODUCTS OF COMBUSTION PROTECTION 363 
 
 or generator. The first practical producer was designed by C. W. 
 Siemens (from which came the name Siemens gas), and consisted 
 of a brick chamber in which the fuel was supported on an inclined 
 grate, and air alone was used. On account of the construction, 
 the producer had to be shut down at frequent intervals in order 
 to clean out the ashes. A modern producer consists essentially of , 
 a cylindrical, fire-brick, combustion chamber containing the bed 
 of fuel through which the air and steam are forced, usually from 
 the bottom, and under pressure; if suction is used, it is termed a 
 suction producer. The resulting gas is taken off at the top 
 through suitable openings. If the air and steam are forced 
 through from the top to the bottom, it is called a down-draft 
 producer. The fuel is fed in at the top through a hopper, and the 
 ashes are cleaned out at the bottom as a rule through a water seal 
 (water seal producer), the action practically always going on 
 uninterruptedly (continuous producer), as it is not economical 
 to take the producer out of service except when the gas is no 
 longer needed. 
 
 Products of Combustion. See page 202. 
 
 Product of Rolling Mills. See page 411. 
 
 Pro-Eutectic. See page 269. 
 
 Pro-Eutectic Austenite. See page 275. 
 
 Pro-Eutectic Cementite. See page 273. 
 
 Pro-Eutectic Ferrite. See page 275. 
 
 Pro-Eutectoid. See page 271. 
 
 Pro-Eutectoid Cementite. See page 273. 
 
 Pro-Eutectoid Ferrite. See page 272. 
 
 Profile (Eng.). The section or shape of rolled iron or steel. 
 
 Progressive Fracture. See page 179. 
 
 Progressive Freezing. See pages 54 and 266. 
 
 Prony Brake. See page 483. 
 
 Proof Load; Strain; Strength; Weight. See page 468. 
 
 Proof Test. See pages 467 and 482. 
 
 Properties of Crystals. See page 121. 
 
 Properties of Materials. See page 330. 
 
 Proportional Limit. See page 334. 
 
 Proportionality. (i) Law of: see page 473; (2) limit of: see page 
 334- 
 
 Protected Metal. See Protection. 
 
 Protection. In cementation: see page 70. 
 
 Protection. The prevention of corrosion (q.v.) in iron or steel, 
 which, however, is only relative, is effected by means of pro- 
 tective coatings or coverings which are either inert or very 
 resistant to corrosion, such as tar or concrete, or are acted upon in 
 preference to the iron, such as zinc, and are of three kinds: (a) 
 those simply adhering to the surface of the object, composed 
 of some extraneous substance, e.g., paint; (6) those formed by 
 the oxidation of the surface (oxide coating) ; and (c) those which 
 may be a combination of the two preceding, or where a metal 
 coating forms an alloy where it comes in contact with the object. 
 Such coatings and the processes for producing them are desig- 
 nated protective, preservative, or inoxidizing. Articles which 
 
364 PROTECTION 
 
 have a protective oxide coating are sometimes termed black 
 iron objects. In practically every case the surface of the iron 
 must be carefully cleaned before any kind of coating is applied. 
 
 Passivity or Passive State. If a piece of iron (also certain 
 other metals) is immersed in concentrated nitric acid, strong 
 solutions of chromic acid or potassium bichromate (chromatic pro- 
 tection), or exposure to certain other strongly oxidizing reagents, 
 it is only slightly attacked; and if subsequently placed in acid or 
 other solution which would ordinarily attack it vigorously, it still 
 remains almost unaffected. The rate of solubility in dilute nitric 
 acid is sometimes made a measure of the degree of passivity; 
 where relatively large proportions of NO2 are evolved has been 
 termed the passive break, i.e., the dividing line. Iron in this 
 condition has been termed passive, passivated, passivified, 
 inactive, altered, or prepared, and, as a contradistinction, when 
 in its ordinary condition, fresh iron. This inactivity may be 
 removed by scratching the surface or touching it with an active 
 substance; also by making it the cathode with the passage of a 
 sufficiently powerful current. The change from the active to the 
 passive condition is not necessarily abrupt, but may be gradual, 
 so that passivity may exist in varying degrees of retardation. 
 
 Anodic passivity or polarization is where the object forms the 
 anode in an electrolyte; non-anodic passivity or polarization, 
 where the object is not part of an electrolytic couple, also called, 
 in contradistinction to the former, chemical passivity. Faraday's 
 oxide or oxygen theory assumed the surface to be oxidized; this 
 had to be abandoned when it was found that chromium could be 
 rendered inactive without actual oxidation. This was modified 
 in the oxide skin or oxide film theory on the assumption that the 
 metal was protected by a thin covering of oxide. Finkelstein's 
 valency theory assumed differences in valency of the metal. 
 LeBlanc's reaction-velocity theory assumed the passage of the 
 metal to be accompanied by a chemical change; if this was slow 
 the metal was passive. Fredenhagen's oxygen charge or 
 oxygen film theory was due to his finding that when an anode was 
 polarized the potential rose gradually, which led him to believe 
 this was due to a slow oxidation, an oxygen film forming over the 
 surface of the electrode. He assumed that oxygen or oxide was 
 present in the metal as a solid solution. Foerster and Schmidt's 
 hydrogen or catalysis theory ; that passivity was the normal state 
 for pure iron, and that activity was due to the presence of some 
 catalytic agent, particularly hydrogen. In the peroxide or 
 adsorption theory it was assumed that iron ions were oxidized to a 
 high oxide (perhaps FeO 3 ) which were then adsorbed by the sur- 
 face of the metal. Sackur's anion discharge theory is similar 
 to LeBlanc's and assumes that the velocity with which the metal 
 is attacked depends on the accessibility of the discharged anion. 
 Reichinstein's constant sum theory states: "The sum of the 
 concentrations of all the constituents of the electrode volume is 
 always constant. Electrode volume is simply an hyyothesis of 
 Reichinstein's to account for the possibility of the displacement 
 of one substance by another. He found that the sum total of all 
 
PROTECTION 365 
 
 concentrations at this surface must be constant, and therefore 
 talked about concentrations. If you substitute for concentra- 
 tion the idea of the extent to which a surface is covered with 
 atoms, then, instead of the sum of the concentrations being 
 constant, you say the total sum of the spaces on the surface is 
 constant. You then get Reichinstein's hypothesis in different 
 language, so you can then talk about electrode volume as the 
 electrode surface." (The above is largely based on The Passive 
 State by Bennett and Burnham, /. Am. Electrochem. Soc., 
 XXIX, 1916). 
 
 Where corrosion is due to electrolysis, methods have been 
 devised or suggested consisting in setting up a counter e.m.f. of 
 greater intensity. This is the principle of the Cumberland 
 process where the shell of the boiler forms the cathode, and the 
 anodes are pieces of iron suspended in the water and insulated 
 from the shell. A continuous current at a low voltage is em- 
 ployed and successful results are claimed; it is also said to be effect- 
 ive in removing scale and in preventing its formation. Pieces 
 (protectors) of zinc, which is electro-positive to iron, connected 
 with the shell, have also been tried, but such practice has received 
 only a limited application. 
 
 Paint, from a commercial viewpoint, is a substance applied in 
 liquid form to produce a protective coating. It is composed of 
 (i) a solid substance in a fine state of division, known as the 
 pigment or coloring matter, and the base or principal constituent 
 (these may be the same), and (2) the vehicle or menstruum in 
 which they are held in suspension. The pigment or base may be 
 a metal or a chemical compound. Where the vehicle is linseed 
 oil, a drier consisting of a salt of manganese or some other sub- 
 stance is often added to hasten the oxidation (hardening) of the 
 oil. The body of a paint is its covering power, i.e., the relative 
 amount of surface a given quantity will cover thoroughly. When 
 more than one coat is applied the first is called the priming coat ; 
 when applied to structural material shipped ready for erection it is 
 termed a shop coat or field coat. A coating employed for pipes, 
 known as Angus Smith's solution, originally consisted of coal tar, 
 tallow, slaked lime, fine rosin, and coal naptha; as used at present 
 the mixture generally consists of coal tar and pitch oil in the 
 proportion of about two to one, and it is heated nearly to the boil- 
 ing point when the pipes, cleaned from scale and rust, are dipped 
 in it. Collodion is occasionally employed for coating objects, 
 but the film is thick, which is disadvantageous for certain pur- 
 poses, and also is easily destroyed. 
 
 Lacquer is a varnish made by dissolving shellac in wood 
 alcohol with the addition of other substances, particularly 
 some pigment. Japan is similar to a varnish made by dis- 
 solving shellac in hot linseed oil to which a drier, such as litharge, 
 is usually added. Black Japan or Japan lacquer is asphaltum 
 dissolved in linseed oil and thinned with turpentine. 
 
 Caustic soda (NaOH) or caustic potash (KOH), in strong 
 solutions, has a marked effect in preventing rust, and for this 
 reason cleaned articles are frequently dipped in a concentrated 
 
366 PROTECTION 
 
 solution of one of these salts. So-called boiler compounds are 
 sometimes used to neutralize free inorganic or organic acids 
 which may be present, and for this purpose usually contain some 
 powerful base such as sodium carbonate. One such compound 
 contains sodium carbonate, tri-sodium phosphate, dextrine, and 
 a substance with tannin. The use of lime direct is objectionable 
 owing to the scale which is likely to result, and its employment is 
 generally restricted to preliminary purification of water in large 
 tanks, which also results in softening the water and so reducing 
 scale for the removal of which, when formed, special compounds 
 are advocated. 
 
 Influence on Corrosion of Certain Elements. A few years ago 
 the theory was advanced that, if iron could be manufactured 
 approximately pure, that is, free from the usual metalloids and 
 impurities, it would show extreme resistance to corrosion. Later 
 work, however, indicates that several of the metalloids, within 
 certain limits, are rather beneficial than harmful in their effects on 
 the corrosion rate. 
 
 Carbon. Under 0.20%, carbon has little influence on corro- 
 sion. From 0.20 to the eutectoid (0.85) percent, there is a gradual 
 increase in the corrosion rate with additional carbon, and from 
 the eutectoid percent up to approximately 1.25% the curve 
 again drops. 
 
 Manganese. A belief that manganese increases corrosion is 
 still held by some metallurgists. Recent work, however, seems 
 to prove that the real offender is sulphur (see Sulphur below), 
 and not manganese, and that the latter, instead of increasing, 
 slightly lowers the corrosion rate. 
 
 Sulphur. The corrosion rate increases directly with the sul- 
 phur content, and corrosion is especially rapid in steels and 
 irons approximately free from copper and carrying an abnormally 
 high amount of sulphur. 
 
 Phosphorus. Phosphorus has little or no influence on the 
 
 corrosion rate. It has been noticed that, when a comparatively 
 
 small amount of phosphorus is added to steel, the corrosion is 
 
 \ slightly less, which is probably due to the deoxidizing effect of 
 
 added phosphorus. 
 
 Silicon. In the amounts normally present in open hearth 
 and Bessemer steel, this element has no effect on corrosion. 
 If as much as 9.10% or more, however, is added, the corrosion 
 rate is increased. 
 
 Copper. Copper has a remarkable influence in lowering the 
 corrosion rate of steel or iron, even when present in very small 
 quantities. It has the effect of neutralizing the influence of 
 sulphur, and the rust film on the surface of the steel gradually 
 becomes protective rather than accelerative as is the case with 
 steels and irons comparatively free from copper. 
 
 Nickel. The influence of nickel is similar to that of copper, 
 except that probably more nickel than copper is required to 
 produce a similar increased resistance. 
 
 Cobalt. It is quite probable that cobalt in the lower ranges 
 slightly decreases the corrosion rate. When cobalt is alloyed 
 
PROTECTION 367 
 
 with steel to the amount of approximately 12%, together with 
 a little chromium, a product is obtained which is practically 
 unacted upon by any corrosive agent. 
 
 Chromium. Chromium tends to reduce corrosion especially 
 in amounts over about 6%. What is known as stainless steel 
 contains about 10 to 15%. 
 
 Oxide Coatings. Rust, produced by slow oxidation and 
 well known by its brownish, yellowish or reddish color, consists 
 principally or wholly of ferric oxide (Fe2Oa), hence readily parts 
 with a portion of its oxygen to the metal beneath, absorbing 
 a fresh supply from the surrounding atmosphere or other medium, 
 thus setting up a catalytic cycle of which it is the agent. The 
 oxide or scale which rapidly forms on iron objects when they are 
 heated to high temperatures consists almost entirely of the 
 magnetic oxide (FesO-i); while it does not so readily part with 
 oxygen, it is only slightly adherent when produced in this way 
 and, being easily detached, offers little protection. Hence the 
 necessity for special treatment to yield an adherent, non-corrosive 
 coating (rust proof coating). One of the simplest methods is 
 known as blueing which is effected by heating an object until 
 the previously cleaned surface takes on a thin oxide film of that 
 color. It is. so thin that it is quickly worn off when handled, 
 and accordingly its protection is relatively slight. Barff's 
 process consists in passing superheated steam over the objects 
 which are heated in a muffle to about 500 F. (260 C.); for more 
 complete protection a temperature of 1200 F. (650 C.) is em- 
 ployed. Such objects are said to be barffed. " George Bower 
 interested himself in this process and tried using air instead of 
 steam (Bower process); he was not successful, however, until 
 his eldest son, A. S. Bower, conceived the idea of using a pro- 
 ducer gas rich in carbonic oxide to reduce the red oxide, as 
 obtained by air treatment, either by barffing, or by subjecting 
 
 the work to acid fumes The air treatment lasted 40 
 
 minutes and the gas treatment 20 minutes, these being repeated 
 alternately four or eight times. Finally the Barff patents were 
 purchased in order to secure a satisfactory first coating of red 
 oxide in a practical manner. The combined process, known as 
 the Bower-Barff process, consisted in heating the articles to be 
 coated in a closed retort to a temperature of 1600 F. (871 C.); 
 superheated steam was then injected, forming a coating of both 
 magnetic oxide (Fe 3 O 4 ) and red oxide (Fe/) 3 ); this first operation 
 lasted 20 minutes, and was followed by the injection, during 
 15 to 25 minutes, of carbonic oxide (CO) from a gas producer 
 which reduced the FeaOs to Fe 3 O4. These operations could be 
 repeated alternately any number of times until a sufficient 
 depth of oxide had been obtained" (Alfred Sang, /. T. R., 
 September 16, 1909). , 
 
 The Swan process is a patented modification of the Bower- 
 Barff process. The articles to be treated are first placed in a 
 muffle furnace with the following substances, preferably as 
 follows: Copper sulphate, 30 parts; sal ammoniac, i part; tannin, 
 2 parts; and glucose,' 3 parts. They are heated to about 1050 
 
368 PROTECTION 
 
 F. (620 C.), and superheated steam is injected for about 30 
 minutes. They are taken from the furnace, permitted to cool, 
 and then submerged in paraffin oil heated to about 150 F. 
 (65 C.). They are then dried in air and have a dead-black, 
 coating. Repeated treatments are not necessary unless a 
 heavier coating is required. In Bertrand's process the iron to be 
 coated is first carefully cleaned by immersion in dilute sul- 
 phuric acid (5%), and preferably brushed. It is then rubbed 
 with grain or sand until quite clean, and immersed for four or 
 five seconds in a bath consisting of 200 grams of acid tin salts, 
 600 grams of sulphate of copper, and 300 grams of sulphovinic 
 acid in 100 liters of water. The work should then have a 
 yellowish bronze color; it is washed in water containing ;Hj% 
 of oxalic acid, dried and heated in an oven the atmosphere of 
 which may be either oxidizing or reducing. The time required 
 varies somewhat according to the temperature employed; but 
 about 10 minutes is stated to give a fairly adherent coating of 
 magnetic oxide which is capable of resisting atmospheric in- 
 fluences very perfectly (Turner). Bontempi's process con- 
 sists in heating iron objects to approximately 1000 F. (540 C.) 
 in a closed and preferably air-tight chamber, the iron having 
 been previously treated according to the Bower-Barff process 
 or not, as desired, when it is subjected to the gas or vapor of 
 one or more non-corrodible substances. When the Bower- 
 Barff process is omitted, the temperature need be only high 
 enough to insure volatilization of the non-corrodible substance. 
 Browning is used largely for gun barrels. The method in use 
 at the Woolwich Arsenal (Journ. I. 6* S. /., 1881) is as follows: 
 The barrels, etc., are first scalded in a solution of soda for 20 
 minutes, and are then washed in clean water. The brown- 
 ing mixture is applied and they are exposed to a damp heat 
 for about i % hours, when they are scalded again and, when cool, 
 the rust is scratched off. This process is repeated four times 
 and then the barrels are cleaned off and oiled. The whole 
 operation takes about 8 hours. The browning mixture consists of : 
 
 Spirits of wine 5 oz. 
 
 Spirits of niter 8 " 
 
 Tincture of steel (chloride of iron) 8 " 
 
 Nitric acid 4 " 
 
 Sulphuric acid 3 " 
 
 Blue vitriol. 4 " 
 
 Water i gal. 
 
 Sometimes browned steel is produced by simply rubbing the 
 surface with a mixture of zinc chloride and olive oil. The 
 Buffingtpn process, used for parts of guns, etc., consists in 
 suspending the objects for five minutes or more in pure molten 
 niter, containing manganese dioxide, at a temperature where 
 sawdust thrown on the surface will burn; the pieces are then 
 hung for a few minutes over the pot and afterward placed in 
 boiling water to remove any niter adhering to the surface; this 
 method produces a fine bronze color. Claudius' process 
 
PROTECTION 369 
 
 consists in dipping the articles in a 5 to 6% solution of man- 
 ganese nitrate and drying them slowly over a fire, the opera- 
 tion being repeated until a coating of the desired thickness is 
 obtained; any loose powder is brushed off after each operation. 
 In Forbes' process the articles are heated in a mixture of man- 
 ganese dioxide or some similar substance mixed with a neutral 
 material. In Gesner's process the articles are heated in gas- 
 fired retorts for about 20 minutes at a temperature of 1000 
 to 1200 F. (540 to 650 C.), when superheated steam is in- 
 troduced for about 35 minutes. After this a small quantity 
 of naphtha is run in and the heating continued for 10 minutes; 
 steam is again admitted for 15 minutes. The De Wees Wood 
 process was earlier than, and practically identical with, the 
 preceding and was applied to sheets. The hydraesfer process 
 (patented by Bradley) is somewhat similar to the Bower-Barff 
 process and requires but one furnace operation which lasts one 
 hour or less; the color of the coating is a blue black. The 
 process owes its name to the use of brass in connection with 
 the partly decomposed steam which is injected into the retort. 
 The metal to be coated is kept at a temperature of about 1100 
 F. (595 C.). A. de Meritens' process consists in placing 
 the object in water at a temperature of 70 to 80 C. (160 to 
 175 F.) where it constitutes the anode of an electrolytic cell. 
 An electric current, just strong enough to decompose the water, 
 is used and the oxygen liberated forms a thin black layer of 
 magnetic oxide which withstands rubbing and may be pol- 
 ished. No previous cleaning is necessary. If the current is 
 too strong the oxide will not be adherent; it is also found ad- 
 vantageous to have hydrogen present in the iron by first passing 
 the current, for a short time, in the opposite direction. 
 
 The Parker rust proof process consists in immersing the 
 pieces to be treated in a bath containing about 2 % of a mixture 
 of phosphoric acid, manganese dioxide, etc., heated to about 
 the boiling point. The pieces, previously cleaned, are allowed 
 to remain in the bath a variable length of time, depending upon 
 their composition, or until effervescence ceases. They are then 
 removed and dipped in oil. The surface produced has the 
 appearance of gun metal. C. Platt's method, intended for wire, 
 consists in exposing it to the action of steam containing acid vapor 
 which produces a fine brown coating in a few hours. It is then 
 heated for an hour at a temperature of 100 to 125 C. (210 to 
 255 F.), dipped in oil, the superfluous oil removed in a cen- 
 trifugal machine, and the wire again heated. 
 
 Spellerizing is a process, devised especially for treating the 
 metal for steel tubes, consisting in first subjecting the skelp at 
 the proper temperature to the action of rolls having regularly 
 shaped projections on their working surfaces, and other rolls 
 with smooth surfaces, the object being to knead and work the 
 surface of the skelp (roll-knobbling) to produce a more adherent 
 scale and one better adapted to resist corrosion, especially in the 
 form of pitting. In G. Weigelin's process the objects are heated 
 in a furnace so arranged that they may be exposed alternately 
 24 
 
370 PROTECTION 
 
 to reducing and oxidizing gases, whereby a film of magnetic oxide 
 is produced. 
 
 Enameling is a method of producing a smooth, opaque, vitre- 
 ous coating (glaze or enamel) on metals. The enamel is usually 
 put on as a powder or solution of which silica is practically 
 always a constituent; this is baked or fused. It may be applied 
 in one coat, or sometimes a non-vitreous material, called the 
 base material, is first applied and heated or burned in to 
 make it adherent, after which the top coat or glaze is fused on. 
 One method of producing a silicate coating on pipes is to cover 
 the cores (in the mold) with a mixture of silicates of lime and 
 magnesia which are fused when the molten metal comes in 
 contact with them and become firmly attached to the surface. 
 Dode's inoxidizing process consists in depositing successive 
 layers of lead or silicate on iron and steel, and then gilding, platin- 
 izing, or bronzing them. The Hydrogen Company's process 
 is used for soil pipes, and requires about two hours. The 
 pipes are heated in retorts to the desired temperature, and 
 steam is admitted for about one hour. Some hydrocarbon 
 liquid is then injected with steam into the retort. The coating 
 produced is claimed to unite with the iron and not form a mere 
 paint. Ward's inoxidizing process is for producing a dull black 
 coating on objects of cast iron or steel by dipping them in or 
 painting them with a solution of some silicate. After dipping, 
 the articles are heated in a furnace at a temperature which causes 
 the silicate partially to fuse and to unite with the iron. 
 
 Metallic Coatings. Various methods may be employed for 
 applying the metal, such as dipping in a molten bath, depositing 
 electrolytically, applying in a finely divided form, as a paint, by 
 welding, and heating in contact with the powdered metal (metallic 
 cementation). Galvanizing (rarely termed zinc plating) is 
 a process for coating metal with a thin layer of zinc. It is 
 so called from the fact that a galvanic couple is formed, of 
 which the zinc is the more electro-positive, and hence, when 
 exposed to corrosive action, is dissolved in preference to the 
 iron, etc. Before the coating is applied, the surface of the 
 object is cleaned from scale and dirt by pickling or some other 
 means. According to the usual method, termed pot galvaniz- 
 ing or hot galvanizing, the object is dipped in molten zinc or 
 spelter (commercial zinc) contained in an iron vessel or pot. 
 at a temperature usually about 810 to 840 F. (430 to 450 C.). 
 The surface of the molten zinc is largely protected from oxi- 
 dation by a layer of ammonium chloride. In Winiwarter's 
 process, intended more especially for sheets-, the tank is kept 
 nearly full of lead (to prevent the formation of hard zinc), on 
 top of which is a layer of zinc about an inch thick containing 
 2 or 3% of tin to promote crystallization. Before coating, 
 the sheets are cleaned A by dipping in a dilute solution of 
 chlorides of zinc and ammonium. In Kuffler's process 
 superfluous zinc is removed from the surface of sheets by means 
 of wire brushes. Bedson's continuous process is that very 
 generally adopted for galvanizing wire (see page 509). Reese's 
 
PROTECTION 371 
 
 process is also a modification adapted for wire, in which the 
 wire is galvanized in bundles without uncoiling, and then put 
 immediately inside the drum of a centrifugal machine by means 
 of which the excess of zinc is thrown to the periphery. Porter's 
 process is devised for removing the excess of zinc from articles 
 by placing them while still hot in a vibrating hopper, the surplus 
 zinc collecting at the bottom, while the articles themselves 
 are delivered before reaching the bottom. Electro-galvanizing, 
 also called cold galvanizing, is where the object to be coated 
 with zinc is attached (af ter^ cleaning) to the negative electrode 
 (kathode) in an electrolytic bath, metallic zinc constituting 
 the anode, and a soluble salt of zinc the electrolyte. In the 
 Cowper-Cowles process the electrolyte is zinc sulphate, which 
 is regenerated by circulating it through tanks containing zinc 
 dust. In S. Wagner's process the zinc anode is covered with 
 flannel saturated with a solution of zinc and is moved over the 
 surface of the object. Electrolytic methods of galvanizing, 
 which differ slightly in details from those described, have been 
 devised by Heathfield, H. Paweck, Pottkoff, Rawson, and 
 Walker. Sherardizing is a process of dry galvanizing invented 
 by Sherard Cowper-Cowles. The articles, after cleaning, are 
 placed in a retort, usually a revolving drum, with zinc dust, 
 commonly called blue powder. This is the flue dust produced 
 in the manufacture of zinc, and contains about 75 to 90% of 
 pure zinc. A small amount of powdered charcoal is added to 
 prevent oxidation of the zinc from the air inside the retort at 
 the beginning of the operation, and the receptacle is closed and 
 heated to a temperature about 200 F. (110 C.) below the melt- 
 ing point of zinc. The zinc appears to form a true alloy with the 
 iron. This method is used principally for objects such as bolts 
 and small castings, and does not appear to be applicable to 
 sheets. After exposure, this coating assumes a grayish-blue 
 appearance, which does not interfere with its resisting properties, 
 called the curing color. 
 
 Coatings of tin, or a mixture of tin and lead, are used prin- 
 cipally for thin plates or sheets, known respectively as tin 
 plates and terne plates, which are described under Sheets and 
 Tin Plate. Nickel plating and copper plating are usually done 
 by electrolytic methods, the object to be coated forming the 
 kathode, a piece of the metal for the coating, the anode, and a 
 solution of some salt of the same metal, the electrolyte. In nickel 
 plating, a preliminary coating of copper is often applied to make 
 the nickel more adherent. Copper may also be deposited from 
 solution by a purely chemical reaction with metallic iron whereby 
 a corresponding amount of the iron goes into solution. 
 
 The electrolytic method is generally used where a relatively 
 thin coating is desired on a finished object; frequently also as 
 a preparation for nickel or other additional plating owing to the 
 better adherence thus secured. This method may also be carried 
 further to secure a thicker layer where the coated steel in the 
 form of billets is subsequently rolled or worked down as in 
 the production of small sections such as rods and wire. In this 
 
37 2 PROTECTION 
 
 second case the same object may be attained by a welding process 
 by first depositing a relatively thin coating and then inserting 
 the piece in a closely fitting tube of copper, the whole being sub-- 
 sequently heated to a moderate rolling temperature and squeezed 
 into intimate contact, usually in a rolling mill. The product is 
 referred to as copper clad steel. Of a similar nature is the 
 Monnot process. Here the copper is cast around a piece of steel 
 and the compound billet then rolled and drawn down, etc., or 
 the heated billet may first be dipped in a bath of copper at a 
 high temperature (to produce a copper-iron alloy film) and then 
 into a second bath at a much lower temperature where the 
 necessary thickness of coating is secured. By the electrolytic 
 or welding methods the junction of the two metals depends 
 only upon the very intimate contact, which is claimed to be 
 better for use as electrical conductors then where the junction is 
 formed by an actual alloy. The Willis' process is somewhat 
 similar but varies in certain details. The term coppered steel 
 is generally understood to refer to a copper coating, but is oc- 
 casionally applied to steel containing, as one of its ingredients, a 
 small percentage of that metal, the preferable term being, 
 however, copper steel (see page 453). In this connection W. H. 
 Walker suggested the term ferro-brass to illustrate the simi- 
 larity of the reduced corrosion of copper steel to that of zinc to 
 which copper has been added (forming brass). 
 
 Coatings of aluminum may be applied as in hot galvanizing, 
 or as a paint the base of which is finely ground aluminum. A 
 number of special methods have been devised. Calorizing 
 is a process for the protection of metals against oxidation at 
 high temperatures. The coating, called insuluminum, is claimed 
 to prevent indefinitely oxidation below 1000 C. (1830 F.) and 
 to increase the life greatly at higher temperatures. It consists 
 in heating the pieces to be treated in a mixture of powdered 
 aluminum, alumina % and about i% of sal ammoniac in a 
 gas-tight receptacle filled with a reducing or inert gas; the heating 
 is slow and the time is usually two or three hours, depending upon 
 conditions and the results to be obtained. Its principal ap- 
 plication is for furnace parts, pyrometer tubes, combustion 
 tubes, etc. (W. E. Ruder). The percentage of aluminum 
 varies from about 5 to 50% by weight. For copper and brass 
 objects the mixture is kept low in aluminum and the heating is 
 carried out at about 700 to 800 C. (1290 to 1470 F.). For 
 steel and iron objects, richer mixtures are employed and the 
 temperature is increased to 900 to 950 C. (1650 to 1740 F.). 
 These mixtures may be used repeatedly with the addition of 
 the amount of aluminum and ammonium chloride necessary to 
 make up the loss. The Van Aller process is very similar, the 
 metallic objects to be coated being heated in revolving drums 
 with mixtures containing finely divided aluminum. Alumaloyd 
 is the trade name for sheets coated with aluminum by a special 
 process. It is claimed that such sheets can be worked without 
 cracking the coating, and that the surface is particularly adapted 
 for painting where a high finish is desired. 
 
PROTECTION 373 
 
 The spraying of metals from the molten state is an old idea 
 for producing powders, and the spraying of a liquid to produce 
 a covering of paint, varnish or enamel is also well known. It 
 has recently been adapted to produce uniform metallic deposits. 
 In the Schoop process a metallic powder is driven at high 
 velocity against the surface of the body to be coated, by means 
 of gaseous jets expanded from considerable pressure. In earlier 
 attempts the metal was melted in a pot, forced under high pres- 
 sure through a fine nozzle, and sprayed on the surface with 
 steam or gas. Morf devised a machine to combine pulveriza- 
 tion and deposition. The essential parts of this machine or 
 pistol are a combined melting and spraying jet and a feed mechan- 
 ism. The metal to be used, in the form of a rod or wire, is fed 
 to the melting flame which can be gas, acetylene, hydrogen, 
 etc., in air or oxygen. For the best cohesion the surface must 
 be thoroughly cleaned, preferably by a sand blast. Schoop's 
 new method is based on the conception that the force with 
 which the solid molecules are driven against the surface brings 
 them into the liquid, or at least the malleable, state, resulting 
 in perfect union and the consequent formation of a homogeneous 
 body (Morcom, /. Inst. Met., 1914, II). A modification in- 
 troduced by C. F. Jenkins is based on the action of an electrical 
 fuse which deposits and blows a shower of very minute metallic 
 particles on the surface. The Lohmann or Lohmannizing 
 process is used for coating iron and steel sheets with a pro- 
 tective alloy which is claimed to extend below the surface and 
 to fill every pore or cavity. It appears to. depend upon the use 
 of what is called the Lohmann bath containing an "amalga- 
 mating" salt and, later, an immersion in a molten alloy. The 
 metal is pickled and then dipped in this bath where a metallic 
 salt is deposited, and the sheets are then dried and immersed 
 in a molten alloy which is kept at a temperature of 950 to 1000 
 F. (510 to 540 C.). When the submerged objects have reached 
 a temperature of about 500 F. (260 C.) the previously deposited 
 salt is driven off and leaves the surface in a perfectly clean con- 
 dition where it is replaced by the coating metal. An important 
 feature of the process is the use of an alloy of zinc, lead and tin, 
 the proportions of which are varied to suit requirements. 
 Kalamein is the trade name for a coating of lead, tin and anti- 
 mony applied in a manner similar to hot galvanizing. It is 
 used especially for tubes and similar objects (said to be kala- 
 meined). It is of a silvery color, resembling the appearance of 
 galvanized objects, but without spangles, and is not cracked or 
 injured by bending or rough handling. 
 
 Miscellaneous methods. A. Bucher recommends applying 
 the following solution: 
 
 Distilled water i% pints 
 
 Tartaric acid 50 grains 
 
 Stannous chloride 150 ' 
 
 Mercuric chloride 30 . " 
 
 Indigo solution 750 " 
 
374 PROTECTIVE COATINGS PUDDLING 
 
 diluted with 100 times its volume of water. A. M. Villon's 
 process consists in subjecting the object to the vapor of sulphur, 
 which combines with the iron forming a sulphide coating. 
 
 Protective Coatings; Process. See page 363. 
 
 Protector. See page 365. 
 
 Proving. See page 467. 
 
 Proximate Analysis. See page 82. 
 
 Proximate Structural Composition. See page 337. 
 
 Pseudocrystalline Structure. See page 125. 
 
 Pseudosymmetry. See page 125. 
 
 Pseudomorph; Pseudomorphic Crystal. See page 122. 
 
 Puddle Ball. See page 376. 
 
 Puddle (Puddled) Bar. See page 377. 
 
 Puddle Cinder. See page 377. 
 
 Puddle (Puddled) Iron. Wrought iron made by the puddling 
 process. 
 
 Puddle (Puddled) Steel. Iron made by the puddling process 
 which contains enough carbon to be hardened by quenching: 
 see page 379. 
 
 Puddle Train. See page 413. 
 
 Puddlers' Candles. See page 376. 
 
 Puddlers' Mine (Eng.).- See page 376. 
 
 Puddling, Puddling Process. This process has for its object 
 the production of wrought or malleable iron (rarely steel) by 
 oxidizing and removing most of the silicon, carbon, manganese, 
 and phosphorus contained in pig iron, the operation being 
 conducted on the- hearth of a reverberatory furnace. The 
 charge during the early stages is molten, but, owing to the 
 temperature not being sufficiently high, the final product is 
 in a pasty state, and for this reason is mechanically mixed 
 with a certain proportion of slag, most (but never all) of which is 
 removed during subsequent steps in its manufacture. 
 
 Until 1784 all wrought or malleable iron was made by some 
 direct process (q. v.) or by similar means. In this year, however, 
 Henry Cort patented the process of puddling (hence Cort's 
 process) by which it is produced from pig iron in a reverberatory 
 or air furnace, without the assistance of an air blast. The 
 furnace at first was lined with sand, which combined with 
 the iron which was oxidized, and caused a very heavy loss; 
 there was little if any removal of phosphorus, and the operation 
 was slow. This method is called dry puddling (on account 
 of the relatively small amount of slag) to distinguish it from 
 the later method (at present used exclusively) where the furnace 
 is lined with some form of iron oxide, called wet puddling or 
 simply puddling, and iron oxide is also charged to form a slag. 
 Formerly puddling meant the practice employing refined pig, 
 and boiling or pig boiling, where unrefined pig was used, but 
 now this distinction is not generally observed, as the pig is seldom 
 refined. 
 
 Puddling Furnace. The hearth (sometimes called basin or 
 puddling basin) is built of cast-iron plates carried on brick 
 walls or on short iron pillars. It is usually about 5 or 6 feet 
 
PUDDLING 
 
 375 
 
 long, and 4 feet wide opposite the charging door. Resting 
 upon and extending around the sides of the hearth is a box, 
 or a double wall, of cast iron 8" or 10" high, through which 
 water circulates. The iron bottom is also sometimes double 
 and water-cooled. Air may be substituted for water as a 
 cooling medium. The fuel is generally bituminous coal, al- 
 though gas is occasionally used (see below under special fur- 
 naces). For coal the grate has an area of about 6 square feet, 
 sometimes 10 or more. The grate bars are separately detach- 
 able to allow of cleaning any part of the fire, and also so they 
 may be replaced when necessary. Between the grate and the 
 hearth is a fire-brick wall (bridge wall) extending from side 
 to side and rising sufficiently high to prevent any of the fuel 
 from passing over on the hearth, or any metal or slag from 
 falling on the fuel. The hearth at the other end, next the 
 
 PIG. 50. 500-lb. puddling furnace. (Stoughton, Met. of I. andS.) 
 
 chimney, terminates in a second bridge (altar) which prevents 
 the overflow of the metal at that end. Beyond this the fur- 
 nace flue inclines downward and terminates at the chimney 
 flue. At the foot of this there may be an opening (floss hole) 
 through which any cinder overflowing the altar may escape, and 
 warmed by a fire to keep this cinder (flue cinder) molten. On 
 the side of the furnace opposite the middle of the hearth is 
 the working door. This is about 20" square and is closed 
 by a slide lined with fire-brick which can be raised or lowered. 
 A small opening (rabbling hole) at the bottom of the door large 
 enough to admit a rabble permits the workman to stir the 
 charge, protected from the heat, and also without admitting a 
 large amount of cold air. The roof of the furnace is an arch 
 about 2 feet high at the fireplace and sloping gradually until, at 
 the chimney, it is less than a foot above the bottom of the flue. 
 
 I 
 
376 PUDDLING 
 
 The furnace just described is known as a single furnace and has a 
 capacity of about 400 to 600 pounds and is the type generally 
 employed. If two such furnaces are placed back to back with 
 the separating wall omitted, it is called a double furnace, and 
 can take a charge over twice as great as a single furnace. Two 
 double furnaces placed side by side, with the separating wall 
 omitted, constitute a double-double furnace or a quadruple 
 furnace. 
 
 Lining and Fettling. The bottom and sides of the hearth 
 are covered with ore or slag rich in iron oxide, etc., which is 
 set by heating to a high temperature. After the preceding 
 charge has been drawn, the hearth is repaired (fettled or fixed) 
 by throwing in up to, say, 200 pounds of ore, etc., slightly mois- 
 tened. The material for this purpose is called fettling or some- 
 times (Eng.) fix, mill fix, or puddlers' mine. Bull dog (Eng.) 
 is calcined tap cinder. Best tap (Eng.) is a specially prepared 
 puddling cinder, consisting principally of magnetic and ferric 
 oxides. The slag in the furnace from the previous heat is 
 commonly allowed to remain. If the lining becomes eaten 
 away, exposing the cast-iron plates, the furnace is said to have 
 a cold bottom. 
 
 Operation. After fettling, about 200 to 600 pounds of pig iron 
 are thrown in, and the door closed. In about 20 minutes 
 they (and some of the oxides) begin to melt, and when fusion 
 is complete the bath is worked with a rabble (an iron tool 
 resembling a hoe) to expose the iron to the action of ' the slag 
 and the flame. The silicon is 'oxidized first, and when this 
 has nearly all disappeared the iron clears, i.e., loses the mottled 
 appearance it formerly had. The phosphorus is also eliminated 
 during this and the later period. The temperature is now 
 slightly lowered and the carbon is attacked, the resulting evolu- 
 tion of carbon monoxide constituting the period known as 
 the boil (rarely called sibbering or stewing). This gas burns 
 in little pale-blue jets of flame, called puddlers' candles, and 
 during its escape puffs up the cinder so that the level of the 
 bath is raised (high boil). Corresponding to the loss of carbon 
 the charge becomes more and more pasty, and the bath drops 
 to its former level (drop of the bath) , and about this time grains 
 of nearly pure iron appear on the surface and the iron is said 
 to have come to nature or to have been brought to nature; 
 this condition is sometimes termed drying, and the iron is 
 called ready iron or young iron. At this point the charge must 
 be well worked up to insure proper welding together of the 
 particles. When the action is complete the pasty mass is 
 broken up with a bar into lumps called balls or puddle balls 
 (the operation is termed balling) of about 100 to 200 pounds each, 
 which are drawn successively with tongs and taken to be 
 squeezed, an operation to expel most of the slag, and also to 
 weld the grains of iron together. The total time of the charge 
 is about i to i% hours. 
 
 If, after charging, the pigs are not moved about, part of the 
 iron may melt at too high a temperature (hot melting) and 
 
 \ 
 
PUDDLING 377 
 
 stick to the bottom (aproning) in an insufficiently decarburized 
 condition. If the removal of carbon is too rapid the grains 
 of iron are coarse and form a compact mass difficult to work 
 and ball (gobbed heat). Rodney (Eng.) is cold cinder sticking 
 to a piece of old iron put into the furnace to help bring on the 
 boil. A cobble is a ball which has been drawn too soon and 
 must consequently be put back in the furnace. 
 
 In some cases part of the cinder may be removed just before 
 the boil and is called boilings, the remainder, if removed at 
 the end of the process, is known as tappings or puddle (puddling) 
 cinder. A furnace is said to have a dry bottom when the slag 
 is drawn off at intervals (this operation is termed bleeding); 
 a wet bottom is where the slag is allowed to remain. The fluid, 
 vitreous cinder on top of the bath is occasionally called floss. 
 
 Squeezing. The machine for this operation is termed a 
 squeezer, and may be of several types. The present form, 
 known as a rotary squeezer, 
 coffee mill squeezer, or Burden 
 squeezer, consists of a cylinder 
 with teeth, like a cog wheel, 
 mounted on a vertical shaft and 
 revolving inside a casing set ec- 
 centrically, the ball being inser- 
 ted at the point where the dis- 
 tance between them is greatest, 
 and the slag expelled while it is 
 carried around to the point where 
 the distance is smallest. On the 
 same principle a cam may be 
 mounted on either a horizontal T?T _ 
 or a vertical shaft and revolve * Si.-Burden squeezer 
 inside a suitable casing (cam "(Thurston, Iron and Steel.) 
 squeezer). Winslow's squeezer has a cam revolving in a 
 vertical plane. Head's squeezer consists of three rolls, pro- 
 vided with grooves and collars, arranged much like a set of plate 
 bending rolls. In Siemens' squeezer, three horizontal rams 
 opposed to each other, operated by hydraulic power or by steam, 
 squeeze the ball on a turntable. The original type of machine, 
 called an alligator squeezer or crocodile squeezer, consisted 
 of an anvil block, upon which the ball was laid, and a vibrating 
 toothed jaw which alternately pressed down upon the ball 
 and rose to allow of changing its position. The use of hammers 
 was still older, and the operation was termed shingling (rarely 
 nobbing). 
 
 Piling. After squeezing, the rough bloom is rolled into a 
 flat bar known as muck bar or puddle (puddled) bar. This is 
 cut up into short lengths (if broken, the operation is known as 
 cabbling) and a number piled together, termed a pile, to be 
 reheated in a furnace, called a reheating furnace, balling furnace 
 (Eng.), or mill furnace, and rerolled, when more of the slag is 
 expelled. Ordinarily the pieces of muck bar are all laid the same 
 way, but occasionally the bars in alternate layers are placed 
 
378 
 
 PUDDLING 
 
 crosswise, and this arrangement is called cross piling Instead, 
 of piles a rough box may be made up, the sides, bottom, and top 
 consisting of pieces of muck bar, the interior of which is filled 
 with miscellaneous small iron scrap; this is termed a fagot 
 (faggot), or box piling, and the operation, fagoting; the iron so 
 produced is sometimes called fagoted iron. 
 
 Product. The material, in general, is called puddled iron, 
 and after rerolling is known as refined iron, refined bar, mer- 
 chant bar, single rolled iron, single refined iron, or No. 2 iron ; 
 if subjected to a second piling, heating, and rerolling, double 
 (doubly) refined iron, double rolled iron, No. 3 iron, best bar, 
 wire iron, or also refined bar. Horseshoe iron is a superior 
 grade made by piling and rerolling old iron horseshoes. Two 
 obsolete products are stampings and lumps which are (Percy) 
 rough plates about 12" square, the former being about i%" 
 thick, and the latter 4" to 5" thick. 
 
 FIG. 52. Alligator squeezer. (Thurston, Iron and Steel.) 
 
 Theories of Puddling. The oxidation of the impurities 
 is due to the oxide of iron present, rather than to the direct 
 action of the oxygen in the air. Siemens considered that 
 magnetic oxide, Fe 3 O 4 , was the active agent (magnetic oxide 
 theory) which is generally accepted, while Snelus referred the 
 action to ferric oxide, Fe 2 O* (ferric oxide theory). 
 
 The action will probably be most readily understood by con- 
 sidering a piece of cast (pig) iron heated in contact with the air. 
 A crust or shell of oxide is formed, and, upon removing this, the 
 metallic iron which is left will be found to contain practically 
 the same percentage of impurities as originally. This oxidizing 
 action may be continued, and the metallic iron which remains 
 will have the same composition even if the temperature is suffi- 
 cient to cause the scale to melt, provided this is allowed to drain 
 off. As soon, however, as the melted scale or slag remains in 
 contact with the iron, particularly if the iron is molten, a new 
 state of affairs is found to exist. The magnetic oxide, FesO-i, 
 of which the scale is principally composed, readily parts with one 
 atom of its oxygen which combines with the carbon, silicon, etc., 
 of the iron, and is itself reduced to ferrous oxide, FeO, thus: 
 
 C + Fe 3 4 = 
 Si + 2Fe 3 O 4 
 
 CO + 3 FeO 
 = SiO 2 + 6FeO 
 
PUDDLING 379 
 
 Most of the ferrous oxide is reoxidized by the air to magnetic 
 oxide which again reacts with the impurities, and this cycle 
 goes on indefinitely; a small portion, however, is reduced to 
 metallic iron which is dissolved by the bath: 
 
 FeO + C = Fe + CO 
 The phosphorus and manganese are similarly oxidized, thus: 
 
 2 P + sFe 3 4 = P 2 5 + i5FeO 
 also 
 
 Mn + Fe 2 3 = MnO + 2FeO 
 
 Scrap Iron. Instead of starting the process with pig iron, 
 as described, scrap iron may be employed. This is generally 
 of small size, called busheling scrap from the fact that it can 
 be gathered up in a bushel basket, and is heated in a furnace 
 (busheling furnace or scrap furnace) the same as a regular 
 puddling furnace. The charge is usually the right amount to 
 form one ball (scrap ball), which is handled in the same way as 
 a puddle ball. The material, after squeezing, and the first 
 rolling, is called scrap bar or bushel (-ed) bar; the final product, 
 busheled iron. A swarfing furnace is the same as a busheling 
 furnace, but the scrap used is much finer. Large pieces of scrap 
 are heated and welded or rolled direct, or made up into fagots as 
 described above. Common iron is wrought iron made from coke 
 pig; finer grades are made from charcoal pig (charcoal iron). 
 
 Puddled (puddle) steel is made in very much the same way 
 as puddled iron, and the same cinder may be used, but the 
 process is arrested before there is such a complete removal of 
 carbon, and must be conducted at a lower temperature. The 
 product contains roughly up to about 0.5% of carbon (wrought 
 iron, usually under 0.1%), but there is no sharply drawn line 
 between the two: the steel must be capable of hardening. 
 
 The working of the charge is now practically always carried 
 on by hand: mechanical devices have been tried from time to 
 time, but have achieved only a temporary consideration. 
 Mechanical rabble, mechanical stirrer, or rarely (Eng.) iron 
 man, is a machine which worlH the charge in an ordinary (or 
 special) type of furnace. The furnace, or simply the hearth, 
 may be rotated in a vertical or a horizontal plane to effect the 
 same thing: such a furnace is called a rotary puddling furnace, 
 rotator, mechanical puddler, puddling machine, or rotating 
 puddling machine. Modifications of these, as well as of ordi- 
 nary furnaces, consist principally of the application of various 
 mechanical devices which need not be mentioned. 
 
 Barnett's process consisted in applying a solution of salt 
 to the lining of the furnace to improve it. 
 
 Beasley's process consists in using a mixture of powdered 
 puddling cinder and blue billy, treated with hydrochloric acid, 
 to which lime and salt are afterward added. This is painted 
 on the surface of the lining, after fettling, and is claimed to 
 remove a greater amount of phosphorus, and also to increase 
 the output. 
 
380 PUDDLING 
 
 According to W. W. Collins* process pig iron was melted in 
 the ordinary way with a large quantity of silicate of iron or 
 other metallic oxide. The melted mass was allowed to remain 
 quietly until the iron began to rise, when it was vigorously 
 worked at a high temperature and balled. The product was 
 to be melted in crucibles with the addition of the desired amount 
 of carbon. 
 
 E. A. Cowper's process consists in blowing preheated air 
 and combustible gas on the bath. 
 
 Hewitt's process consisted in granulating the pig and mixing 
 it with oxide of iron, the melting and working being conducted 
 as usual. 
 
 Hunt's process consisted in working metal, partly decar- 
 burized in a Bessemer converter, in a puddling furnace or a 
 charcoal hearth. 
 
 In Jones and Jones' process partial purification of the pig 
 was performed in the ordinary way, the final treatment and 
 balling being conducted in a rotary furnace. 
 
 In W. Middleton and P. Hayward's furnace between the 
 ordinary puddling furnace and the chimney is a retort, heated 
 by the waste gases, in which the pig iron, before being intro- 
 duced into the furnace, is melted and purified with a blast of 
 air. 
 
 The Pietzke process employs a special furnace which is 
 gas fired and is connected directly with a gas producer. It 
 has two hearths which can be rotated jointly 180. The charge 
 is introduced into the hearth which is farthest from the fire, 
 and the operation is completed by rotating it to the position 
 nearest to the fire, two charges being worked at the same time. 
 
 In Riepe's process (for steel) about 280 pounds of pig were 
 melted and cinder was added. It was then puddled with the 
 addition of a little black oxide of manganese, common salt, and 
 dry clay previously ground and mixed. When this had acted for 
 a few minutes, 40 pounds of heated pig were put in, and boiling 
 .commenced. When grains began to form, they were worked 
 under. He claimed that the most important part of the process 
 was the regulation of the temperature during the final operation. 
 
 Sherman's process consisted in adding potassium iodide 
 to the metal under treatment. 
 
 W. Spielfield, to prevent oxidation of puddled or raw steel, 
 heated the lumps or balls in retorts or closed vessels. 
 
 Taylor's process was to cool the puddle balls, without squeez- 
 ing, then crush them and Separate the small refined particles 
 from the coarse unrefined ones. The former were heated and 
 balled; the latter retreated. 
 
 E. Bonehill used direct metal with mixers. Guenyveau 
 suggested a steam and air jet; Guest and Nasmyth, a steam 
 jet; Trick, Davis, Daniel and Phillips also suggested steam. 
 
 J. J. Osborne's process consisted in adding a. physic com- 
 posed of various proportions of salt, burnt lime, and hammer 
 slag. Ostlund proposed, in the case of refractory Swedish 
 pig, to refine in a revolving iron pot, lying in an inclined posi- 
 
PUDDLING BASIN PURIFICATION PROCESSES 381 
 
 tion, and heated with carbonic oxide introduced through a 
 blowpipe. In Sterling's process about half a per cent of tin 
 was added to the charge, but this made the iron difficult to 
 forge and weld. 
 
 Puddling Basin. See page 374. 
 
 Puddling Cinder. See page 377. 
 
 Puddling Furnace. See page 374- 
 
 Puddling Machine. See page 379. 
 
 Puddling Mine (Eng.). Roasted hematite, suitable for use in 
 puddling furnaces. 
 
 Puddling Operation ; Process. See page 376. 
 
 Puddling Product. See page 378. 
 
 Puddling, Theories of. See page 378. 
 
 Puffed. Of rolls: see page 430. 
 
 Pull Over Mill. See page 408. 
 
 Puller Out. See page 115. 
 
 Pulling. Of castings: see page 56. 
 
 Pulling Test. See page 469. 
 
 Pulpit. An elevated platform commanding a view of the entire 
 mill, where the various appliances are situated for controlling its 
 operation. 
 
 Pulverize. To reduce to powder or a fine state of division by 
 crushing or grinding. 
 
 Punch. A machine or tool for making holes in metal by forcing out 
 a certain portion. 
 
 Punching. Producing a hole in a body by driving a blunt-nosed 
 instrument through it, the displaced material being almost 
 entirely removed from and forced out at the farther side, only a 
 very small proportion being forced into the wall (distinction from 
 piercing) ; see also Cold Working and Forging. 
 
 Punching Test. See page 477. 
 
 Punish. To subject material to very severe or abusive treatment. 
 
 Pure. Of materials, free from impurities or undesirable elements, 
 or where these are so low they do not exert a harmful influence; 
 degrees of chemical purity: see page 89. 
 
 Pure Cast Iron; White Iron. Pig iron nearly free from everything 
 but carbon. 
 
 Pure Chemistry. See page 81. 
 
 Pure Flexure. See page 332. 
 
 Pure Stress; Normal Stress; Internal Normal Stress; Shearing 
 Stress. See page 332. 
 
 Purification. (i) Of metals: see Purification Processes, also page 
 56; (2) of water: see page 366. 
 
 Purification Processes. Those which are concerned (a) prin- 
 cipally wi h the removal from pig iron of silicon, phosphorus, 
 and sulphur, the action being stopped when the carbon is at- 
 tacked, the product being further treated in some other process; 
 and (7>) embracing certain details or modifications applied to ordi- 
 nary processes for making iron or steel. From a practical stand- 
 point the term is not considered to include the regular processes for 
 the manufacture of wrought iron and steel, although from strictly 
 theoretical considerations they would also be included. 
 
382 
 
 PURIFICATION PROCESSES 
 
 Oxidation is the general means employed, the metal treated 
 being nearly always in a molten condition. Decarburization 
 (decarbonization), desulphurization, dephosphorizatipn, and 
 desiliconization are the technical terms used respectively for 
 the removal of carbon, sulphur, phosphorus, and silicon. The 
 general principle to be observed is that at a low temperature, 
 with oxidizing conditions, and in the presence of a basic slag 
 
 FIG. 53. Melting finery. (Stoughton, Met. of I. & S.) 
 
 (basic purifying processes), phosphorus and silicon are oxi- 
 dized in preference to carbon. If the slag is not basic then 
 the phosphorus will not be removed. Under oxidizing con- 
 ditions the removal of sulphur is uncertain. Under strongly 
 reducing conditions, and with a basic slag, as in the blast furnace, 
 
PURIFICATION PROCESSES 383 
 
 the removal of sulphur is under fairly good control, the action 
 being due to the formation of sulphides of calcium and manganese 
 which pass into the slag. 
 
 The terms commonly employed for this special treatment 
 are fining, refining, hearth refining, refinery process, or refin- 
 ing process, and the furnace employed is called a finery, finery 
 fire, refinery, refinery hearth, refining hearth, running-out 
 fire, and run-out fire. These embrace the earliest method 
 employed which is still used to a limited extent. The appara- 
 tus consists df a hearth, generally rectangular, built up of naked, 
 water-cooled, iron plates, blast being usually supplied by two 
 tuyeres opposite to each other, and with a capacity of about 
 ^ to 2 tons of pig. The fuel is either coke or charcoal (coke finery 
 or refinery; charcoal finery or refinery), and the pig is charged 
 either molten or, more commonly, solid. The fuel is burned by 
 the blast from the tuyeres, which also supplies the necessary 
 oxygen for oxidizing the silicon, etc. If ore is added part of the 
 phosphorus is removed. Each charge takes about two hours, 
 less if the metal is initially molten. The product (fine metal, 
 finer's metal, refined metal, metal, or refined cast iron) is tapped 
 out on the iron plates of the floor (plate metal) or into iron molds. 
 It has a white fracture (white metal) due to the absence of silicon. 
 It is sometimes tapped directly into the furnace in which the final 
 treatment is to take place and the furnace is then termed a melt- 
 ing finery or refinery. The loss of iron is about 5 to 20%, and the 
 fuel required, about J^ to % of the weight of the metal charged. 
 Parry tried to hasten the process by blowing a jet of air and 
 superheated steam on the bath of pig in a refinery, which modi- 
 fication he called a steam refinery. A melting down refinery 
 is one in "which- selected pig and scrap are employed, instead 
 of pig alone. The product of charcoal fineries or charcoal 
 hearths is frequently known as charcoal hearth cast iron, and 
 the process is sometimes called frischen process, from the 
 German, whence the name German forge sometimes applied. 
 Where the process is carried further, and wrought iron is produced, 
 will be found discussed under Charcoal Hearth Processes. 
 
 Pig washing processes are a modification of ordinary refining. 
 They consist in treating molten pig iron with molten oxides 
 (oxides of iron, occasionally mixed with oxides of manganese) 
 in a reverberatory furnace. At the low temperature employed, 
 and in the presence of the very basic slag, most of the silicon 
 and the phosphorus are removed, the metal being tapped out 
 before the carbon has been materially attacked. The elimi- 
 nation of the silicon and the phosphorus may amount to 90 
 or 95%. In Bell's pig washing process (Bell's dephosphoriz- 
 ing process) the molten pig is agitated with molten oxides of 
 iron; Krupp's pig washing process (patented a couple of months 
 later) is essentially the same, except that a certain proportion 
 of oxide of manganese was used and the operation was usually 
 carried out in a furnace with a revolving hearth (Pernot fur- 
 nace). They are now generally referred to as the Bell-Krupp 
 pig washing process, and the special addition of oxide of man- 
 
384 PURIFICATION PROCESSES. 
 
 ganese is dispensed with as unnecessary. The product is called 
 wash metal, washed metal, or washed pig. 
 
 Slag processes are those in which molten slag is employed, 
 and pig washing should properly be included. In the Talbot 
 slag process a basic slag consisting of iron oxide and lime is first 
 made in a regenerative furnace and is then poured into a vessel 
 of suitable form (like a ladle) so it forms a deep column. The 
 molten pig to be treated is poured on top of this column through 
 which it sinks and, during its passage, a considerable quantity 
 of silicon is removed, together with some of the carbon and 
 phosphorus. The treated metal is then transferred to a basic 
 open hearth furnace, and the purification completed in the 
 usual way. The Knoth slag process was designed especially 
 for use in connection with the basic open hearth process, to 
 effect a preliminary purification. The molten slag from the 
 previous heat is transferred to a ladle or other suitable receptacle, 
 and lime and other basic materials are added to give it the proper 
 composition. It is then returned to the regular furnace on top 
 of the next charge of molten metal. S. B. Sheldon's process 
 appears to be very similar to that devised by Knoth. The slag 
 at the end of the refining operation is transferred to an auxiliary 
 furnace where fresh basic material is added, the whole made fluid, 
 and then put back into the original furnace for the next operation. 
 
 Following are brief descriptions of processes which have 
 been suggested and tried from time to time with varying degrees 
 of success. 
 
 Aubertin and Boblique's process had for its object dephos- 
 phorization by the action of alumina or fusible aluminates, 
 in puddling or in some steel-making process, it being claimed 
 that phosphate of alumina was more stable in the 'presence of 
 silica than the phosphate of lime or magnesia. 
 
 Bacon and Thomas' process was designed for the removal 
 of silicon from pig iron by melting it in a cupola with the addi- 
 tion of oxide of iron and limestone. 
 
 Win. Baker's process consists in blowing air on the surface 
 of molten pig as it flows from the blast furnace in a specially 
 designed trough. 
 
 In Ball and Wingham's process molten pig iron, high in sulphur, 
 was treated with potassium cyanide, sodium carbonate, and 
 potassium carbonate, either singly or together, and in some 
 reported analyses the elimination of sulphur varied from 83 to 
 100%. 
 
 Bell's refining process, the product of which was to be used 
 in puddling, consisted in oxidizing the silicon in a Bessemer 
 converter, carbonaceous matter being introduced with the 
 blast, or spiegel added, if there was danger of removing too 
 much of the carbon, so the phosphorus would not be properly 
 eliminated in the puddling operation. The blown metal was 
 to be used molten. 
 
 Brinell's process is a modification of the Ellershausen process 
 (see below). An ingot mold is partly filled with molten pig 
 iron, and when solidification is about to take place a quantity 
 
PURIFICATION PROCESSES 385 
 
 of fine ore is thrown in until the mold is full. The ingots so 
 produced are intended to be used in the open hearth process 
 in place of ordinary pig iron. 
 
 Brown's process for "neutralizing" phosphorus by the addition 
 of bichromate of potash is absurd. 
 
 Budd's process for removing silicon consisted of running the 
 metal from a blast furnace into shallow pans lined with a dried 
 paste of iron ore; in another process, a proportion of sodium 
 nitrate was mixed with the iron ore. 
 
 Bull's process was designed to effect dephosphorization in 
 either the Bessemer or the open hearth process by blowing 
 steam through the bath. It was claimed that, after the other 
 impurities had been removed, the steam reacted with the phos- 
 phorus forming a volatile phosphide of hydrogen. Owing to 
 the chilling action of the steam, the process was not successful. 
 Chute's process (recently patented) would seem to be nothing 
 but an application of the Ellershausen process (see below), his 
 claim of discovery being "that by adding powdered ore to a 
 stream of high-silicon pig iron flowing in a runner to the pig 
 beds that the silicon and manganese were reduced in amount." 
 The process was to be used in connection with the open hearth 
 process, the metal being added in a molten condition. 
 
 In the Detmold process pig is melted in a reverberatory 
 furnace similar to that used for puddling, and air is blown on 
 the surface. 
 
 A. de Vathaire suggested the use of cyanide of barium or 
 other alkaline earth to effect desulphurization. The opera- 
 tion was to be performed in a non-oxidizing atmosphere, pref- 
 erably in a revolving drum lined with carbon or lime. 
 
 The distillation process, so called, was performed in a crude 
 form of blast furnace: before tapping, the tuyeres were inclined, 
 and the blast directed upon the molten pig iron in the hearth. 
 Eaton's process was claimed to effect the removal of phos- 
 phorus, carbon, and silicon from planed bars of cast iron by 
 immersing them in fused alkaline carbonates. 
 
 The Ellershausen process consists in treating the molten 
 metal flowing from a blast furnace with oxides lining the run- 
 ners, which effects a partial removal of the silicon and carbon 
 (probably some of the phosphorus and manganese also). The 
 process was designed originally for treating pig to be used for 
 puddling. A modification has occasionally been employed 
 abroad in foundries, where a certain amount of silicon is re- 
 moved by throwing fine ore, previously heated and dried, upon 
 the stream of metal as it flows out of the cupola. 
 
 In Fament's process phosphorus and sulphur were to be 
 removed from any grade of iron by treating it in heated retorts 
 with a current of hydrogen. 
 
 Farrar's process consisted in treating pig with a mixture of 
 sal ammoniac, ferrocyanide of potash, and manganese (oxide?). 
 Garnier's process for dephosphorizing is practically identical 
 with present basic open hearth practice. It consisted in charging 
 lime and ore before the other materials. 
 25 
 
386 PURIFICATION PROCESSES 
 
 James Gregory and William Green claimed that, by allowing 
 broken or granulated pig iron to remain in water for some time, 
 it was made better and tougher. 
 
 Fernand Hamoir's process was for refining pig iron previous 
 to puddling. The pig, while being tapped from the blast fur- 
 nace, was to be subjected to a jet of air derived from the blast 
 used for the furnace. 
 
 J. Haythorne's process was evidently to be used in connec- 
 tion with the puddling process, and would seem to have been 
 based upon questionable principles. While the metal was 
 molten, he added a mixture of dioxide of manganese, oxide of 
 tin, zinc, or lead (!), quicklime, potassa or soda, saltpeter or 
 ammonia, and brick dust or calcined clay. 
 
 In Heaton's process nitrate of soda was placed in the bottom 
 of a ladle or other suitable vessel, being kept in place by an 
 iron grating, and the molten pig iron was poured on top. It 
 was claimed that the action of the nitrate removed some of 
 the phosphorus, all of the silicon, and nearly all of the sulphur. 
 
 The Henderson process, as originally applied to the puddling 
 process, consisted in adding fluorspar and titaniferous iron 
 ore to the slag, with the idea that the impurities would pass 
 off as volatile fluorides. At Birmingham, Ala., a modification 
 (Henderson steel process) was used for a time in making steel 
 from phosphoric pig. The molten pig was first desiliconized 
 and partly decarburized in an auxiliary chamber of a special 
 furnace, and was then run into a basic lined furnace and treated 
 with dolomite and fluorspar. It would appear that the de- 
 phosphorization was due to the dolomite rather than to the 
 fluorspar. 
 
 Heerzeele and Paulis attempted to purify pig (and to make 
 steel) by heating it in contact with steam. 
 
 Marcus Lane's process consisted in running the fused metal 
 from a melting furnace into a special refining furnace, so placed 
 that the metal, on entering, had a rotary motion. This motion 
 was continued by means of a blast striking the metal at an 
 angle which also served to decarburize it. As this action was 
 apt to be too rapid, carbon was added at intervals to give time 
 for the impurities to be removed. 
 
 In J. G. Martien's process the molten metal from the blast 
 furnace or the refinery furnace passed through gutters where 
 jets of air or steam were blown up through it. 
 
 The Massenez process (Hoerde process or Hilgenstock 
 process) for desulphurizating is based upon the fact that sulphur 
 combines with manganese in preference to iron, the resulting 
 manganese sulphide being insoluble in the molten iron, and 
 therefore passes off into the slag if sufficient time is allowed. 
 Pig iron, high in sulphur and low in manganese, is mixed with 
 pig containing a considerable proportion of manganese (ferro- 
 manganese may also be used) both being in the molten condi- 
 tion. A modification consists in charging oxide of manganese 
 in a bath of metal, part of the manganese being reduced and 
 effecting the removal of the sulphur. 
 
PURIFICATION PROCESSES 387 
 
 J. B. Nau's process is designed to purify pig to a certain 
 extent by running it into a cupola of special construction filled 
 with lumps of iron ore and lime previously heated, the metal 
 being tapped out after a few minutes. 
 
 Parry melted wrought iron in a cupola or blast furnace and 
 repuddled it to obtain a further elimination of phosphorus 
 and sulphur, sometimes repeating these operations. He em- 
 ployed a special form of cupola in which one tuyere was hori- 
 zontal, while another, at the opposite side, was inclined down- 
 ward to obtain a very high temperature at the bottom of the 
 furnace. He also used a reservoir or vessel provided with a 
 number of sets of tuyeres in which the carburized metal could 
 be softened by jets of air from the bottom or on top. 
 
 Peckham's process was intended for the purification of iron and 
 steel in a Catalan forge or puddling furnace. It consisted in 
 removing the impure cinder as fast as formed, and replacing with 
 a pure slag, a flux being used for thinning when the slag was too 
 viscous. 
 
 Charles Peter's process consisted essentially in the use of a 
 small reverberatory furnace at the top of a special narrow 
 cupola of which it formed a part. As the iron was melted in 
 the former it fell in granules through the latter where it was 
 acted upon by the air which entered the tuyeres at the bottom 
 end. 
 
 In Prince's process, cast iron is treated in a ladle by blowing 
 air through it, and it is claimed that 30 to 50% of the sulphur is 
 removed by causing it to unite with manganese oxide and so 
 pass into the slag; ferro-manganese may be added to promote this 
 action. 
 
 In Jacob Reese's process steel (probably wrought steel) 
 was to be refined with an oxidizing blast in a coke refinery, a 
 layer of metallic oxide being interposed between the fuel and 
 the metal. 
 
 Rollet's process consisted in melting pig iron with a slag 
 composed of lime, iron ore, and fluorspar in a basic lined cupola 
 of special construction in which the tuyeres were so arranged 
 that the conditions could be made oxidizing or reducing as 
 desired. This process was intended to be auxiliary to some 
 steel-making process. 
 
 The Saniter process for desulphurizing depends upon the 
 use of calcium chloride in a slag containing a high proportion 
 of lime, the principal action of the calcium chloride being, 
 apparently, to render the slag fluid. Fluorspar is also added 
 for this purpose. It may be used in treating (a) molten pig 
 iron in a ladle before it is cast into pigs, and (6) in the basic 
 open hearth process or the basic Bessemer process. 
 
 Thomas Shaw's process is for purifying pig iron by directing 
 a jet of dry steam upon it as it flows out of a cupola furnace. 
 
 The Sherman process, like Brown's, had for its object "neu- 
 tralizing" but not removing the phosphorus in steel, and is 
 equally absurd. 
 
 Siemens' purifying process consisted in heating iron oxide 
 
388 PURIFICATION PROCESSES PUT ON 
 
 spread uniformly over the hearth of an open hearth furnace, 
 followed by or mixed with scrap metal or puddled iron. These 
 were heated to a white heat, and molten pig iron added. The 
 partially purified metal was then run irxto another open hearth 
 furnace and finished as usual. 
 
 In Smyth's process pig iron was purified in a Bessemer con- 
 verter by introducing various chemical compounds with the 
 blast. 
 
 B. P. Stockman's process is similar to that of Heaton (see 
 above). It effects a preliminary refining by running molten 
 pig iron upon a mixture of nitrate of soda, magnetic iron oxide, 
 common salt, and black oxide of manganese (manganese dioxide) 
 contained in a suitable vessel. The action is very violent 
 and as soon as it is over the metal is finished in an open hearth 
 furnace in the usual way. 
 
 O. Thiel, one of the originators of the Bertrand-Thiel process, 
 refines pig iron in a stationary open hearth furnace, using a 
 basic oxidizing slag in a manner very similar to Surzycki's 
 modification of the Talbot process (see page 316), there being 
 a number of tap holes at different levels, and only a portion 
 of the charge being tapped out each time, which is finished in 
 another furnace; the charge may also be finished in the same 
 furnace. 
 
 E. A. Uehling's process consists in treating molten cast iron 
 while in the ladle with various materials to eliminate impurities. 
 
 E. von Maltitz refines molten pig iron by putting it in a ladle 
 or other vessel and covering it with a basic slag; it is caused 
 to circulate, and a-jet of air is directed against the surface under 
 the slag covering. 
 
 Walrand's process is intended to effect dephosphorization of 
 a bath by successive removals of the basic slag and further 
 additions of iron oxide and lime. 
 
 Warner's process is somewhat similar to that of Heaton 
 (see above), nitrate of soda being replaced by ground lime, 
 soda ash (crude sodium carbonate), and small amounts of 
 other materials, upon which the molten pig iron is run, to be 
 later cast in molds when the. purifying action is complete; 
 this was stated to require about 10 minutes. 
 
 Wellman and Schwab's process was to effect a preliminary 
 partial refinement of pig iron in a basic-lined mixer or other 
 suitable vessel in which the metal ccfuld be kept molten. Lime 
 and ore were added and at intervals portions of the bath were 
 removed and used in the regular open hearth process. 
 
 J. G. Willans' process does not seem to possess any special 
 novelty. Pig iron, in contact with carbonaceous matter, is 
 melted in a cupola, a small amount of silicon being removed, 
 but probably not any phosphorus. 
 
 Purifying Process. One in which impurities are removed. 
 Purity of Chemicals. See page 89. 
 Purple Ore. See page 245. 
 Purple Temper. Oxide color: see page 230. 
 Put On. Of the blast, to start. 
 
PYRAMIDAL CLEAVAGE PYRRHOTITE 389 
 
 Pyramidal Cleavage. See page 1 24. 
 
 Pyramidal System. Of crystallization: see page 120. 
 
 Pyrheliometers. See page 207. 
 
 Pyrite. See page 245. 
 
 Pyrocrystalline. See page 122.. 
 
 Pyroelectrplysis. See page 89. 
 
 Pyrognomic. See page 204. 
 
 Pyrolusite. MnO 2 ; an ore of manganese employed in the manu- 
 facture of ferro-manganese. 
 
 Pyrolysis. See page 204. 
 
 Pyrometallurgy. Where heat is applied to induce the desired reac- 
 tion, usually by causing partial or complete fusion. 
 
 Pyrometamorphism. See page 122. 
 
 Pyrometer. See page 205. 
 
 Pyrometer Effect. See page 203. 
 
 Pyrometric Scale. See page 204. 
 
 Pyrometry. See page 205. 
 
 Pyromorphous. See page 122. 
 
 Pyrophoric. See page 204. 
 
 Pyrophotometer. See page 208. 
 
 Pyroscope. See page 208. 
 
 Pyrrhotite. See page 245. 
 
Q 
 
 Quadratic System. Of crystallization: see page 120. 
 Quadravalent. See page 86. 
 Quadruple Puddling Furnace. See page 376. 
 Qualitative Analysis. See page 82. 
 
 Quality. (i) The suitability of a material for the purpose for 
 which it is intended; (2) by common acceptation (a) the process 
 by which steel is manufactured (e.g., open hearth steel) and (6) 
 the purpose for which it is intended (e.g., boiler steel). 
 Quality Figure; Formulae. See page 340. 
 Quality Steel. See page 443. 
 ^ lantitatiye Analysis. See page 82. 
 ititative Microscopy. See page 284. 
 irternary Alloy. See Alloy. 
 
 jrnary Compound. See page 88. 
 
 Steels. See page 443. 
 
 ternary System. Of crystallization : see page 1 20. 
 ji Tempered. See page 231. 
 ich Bend Test See page 476. 
 
 lenching. (i) Of coke: see page 96; (2) of steel: see page 227. 
 lenching Bath. See page 227. 
 Quenching Charge. See page 233. 
 Quenching Hardening. See page 227. 
 Quenching Medium. See page 227. 
 Quenching Temperature. See page 227. 
 Quick Cement. See page 67. 
 Quick Lime. See pages 175 and 396. 
 Quick Speed Steel. See page 446. 
 Quincke's Hypothesis. Of foam cells: see page 121. 
 
R 
 
 R. (i) Reaumur scale: see page 204; (2) to indicate a rising 
 temperature: see page 205 
 
 Ra. Chemical symbol for radium: seepage 84. 
 
 Rb. Chemical symbol for rubidium: see page 84. 
 
 Rh. Chemical symbol for rhodium: see page 84. 
 
 Ru. Chemical symbol for ruthenium: see page 84. 
 
 Raapke Converter. See page 24. 
 
 Rabble. An iron instrument resembling a hoe used to stir a 
 metallic bath on the hearth of a furnace; sometimes called clot 
 Eng.), rarely, rake. 
 
 Rabble Plate. An iron plate welded to the end of a rod to form a 
 rabble. 
 
 Rabbling Hole. See page 375. 
 
 Rack. A mechanical device for transmitting power, consisting of a 
 long bar (generally of cast steel) on one surface of which are 
 teeth which engage with those of a pinion which it rotates or by 
 which it is moved. It is commonly employed for regulating 
 the height of the top roll in a blooming mill, etc. 
 
 Radial Crystals. Forming a radiating structure: see page 125. 
 
 Radiant Energy; Heat. See page 200. 
 
 Radiating Arc. See page 153. 
 
 Radiating Structure. See page 125. 
 
 Radiation. (i) General: see page 200; (2) law of: see page 200. 
 
 Radiation Curve. See page 200. 
 
 Radiation Furnace; Heating. (i) Electric furnace: see page 153; 
 (2) heating furnace: see page 183. 
 
 Radiation Pyrometer. See page 207. 
 
 Radical. In chemistry: see page 87. 
 
 Radio-Balance. See page 207. 
 
 Radiograph. See page 285. 
 
 Radiometer. See page 205. 
 
 Radiomicrometer. See page 205. 
 
 Ragging. See page 407. 
 
 Rail Failures. "Because of the increased attention now being 
 given to the rail question it is important that the distinction 
 between rail failures and broken rails be clearly understood by 
 the public as well as by railway men. Failed rails as reported by 
 the railways, comprehend all rails removed from the track 
 because of defects, including those broken; those having crushed 
 or split heads, broken bases, etc. Many of these defects appear 
 gradually, affording ample opportunity for removal of the rail 
 before complete failure, and seldom causing serious accidents. 
 It is only the rails actually broken, and but a small proportion of 
 
3Q2 RAILER RECALESCENCE CURVE 
 
 these, which give rise to accidents. An analysis of the failures 
 reported in a tonnage aggregating 1% million tons shows but 
 35% of the rail failures reported can be properly classed as 
 rail breakers" (Ry. Age Gaz., May 24, 1912, p. 1143). 
 
 Railer. A kind of buggy or car, without sides, for carrying ingots, 
 etc. 
 
 Raising Hammer. See Hammer. 
 
 Rake. (i) Of shears: see page 412; (2) a rabble (rare). 
 
 Ramage Process. See page 166. 
 
 Ramdohr Process. See page 145. 
 
 Ramming. See page 296. 
 
 Ramming Block. See page 300. 
 
 Ramsbottom Reversing Mill. See page 408. 
 
 Ramshorn Test. See page 476. 
 
 Rapid Cement. See page 67. 
 
 Rapid Combustion. See page 202. 
 
 Rapid Tool Steel. See page 446. 
 
 Rapping; Rapping In. Of patterns: see page 296. 
 
 Rare Metal Couple. See page 209. 
 
 Rash. On sheets: see page 430. 
 
 Rat Tail. See page 17. 
 
 Ratch. See page 508. 
 
 Rate of Combustion. See page 203. 
 
 Rating of a Rolling Mill. See page 410. 
 
 Ratiometer. See page 208. 
 
 Rational Formula. See page 86. 
 
 Rattle Barrel. See page 58. 
 
 Raw. (i) Material in its natural state, or as produced, without any 
 subsequent treatment, e.g., ores which are not roasted, or iron 
 which has not been refined; (2) of cement bars: see page 71. 
 
 Raw Coal Iron (rare). Pig iron smelted with coal. 
 
 Raw Gas. See page 33. 
 
 Raw Limestone. See Flux. 
 
 Raw Steel. Natural steel: see page 304. 
 
 Raw Steel Processes. See pages 76 and 78. 
 
 Rawson Process. See page 371. 
 
 Razor Temper. See Temper. 
 
 Reaction. (i) In chemistry: see page 86; (2) in connection with 
 stresses: see page 336. ..: 
 
 Reaction Slag. See Slag. 
 
 Reaction Velocity Theory. Of passivity: see page 364. 
 
 Reactivity. Ability to react. 
 
 Ready Iron. In puddling: see page 376. 
 
 Reagent- See page 86 
 
 Reaumine. "Iron of Reaumur:" name suggested for malleable 
 cast iron. 
 
 Reaumur Iron. See page 257. 
 
 Reaumur Method.- Of quenching: see page 229. 
 
 Reaumur Process. See page 258. 
 
 Reaumur Scale.- See page 204. 
 
 Recalesce; Recalescence. See page 265. 
 
 Recalescence Curve. See page 267. 
 
RECALESCENT POINT RECARBURIZATION 393 
 
 Recalescent Point. See page 265. 
 
 Recarbonization. Recarburization, q.v. 
 
 Recarburization. Sometimes called recarbonization ; in its 
 special sense, adding carbon in some form to metal (partially) 
 decarburized in some steel-making process to obtain the proper 
 percentage of carbon in the finished steel; also used as a general 
 term for the addition of all material used to give steel the de- 
 sired composition and to effect its deoxidation. In the latter 
 sense it is perhaps preferable to call this material additions 
 (also called recarburizing additions, final additions, or finishing 
 metal). To indicate some particular material its name is 
 prefixed, e.g., manganese addition. The additions are frequently 
 made cold, generally in the ladle (ladle additions), but if they 
 are in such large amounts that there is danger of chilling the metal 
 they may be (a) preheated to a cherry red, (b) melted, or (c) added 
 in the furnace (furnace additions), either wholly or in part. The 
 practice of adding pig iron in the furnace to increase (bring up or 
 fetch up) the percentage of carbon (called in England pigging 
 back or pigging up), is usually restricted to the acid processes on 
 account of the danger of rephosphorization. The ladle additions 
 are made while the heat is being tapped, and an important 
 point is to get them in before much of the slag has appeared. 
 Darby's process of recarburizing consists in adding fine coal 
 to the metal as it runs into the ladle; a hopper and funnel are 
 generally employed to control the rate of flow of the coal. In 
 the Dudelingen process (Meyer process) fine coal, with about 
 10% of milk of lime as a binder, is pressed into bricks and dried, 
 these being thrown into the ladle; it was devised for use in the 
 manufacture of basic Bessemer steel. Robert Mushet's process 
 consisted in adding spiegel or some other form of manganese. 
 Nickel, as nickel scrap or ingot nickel, is usually charged at the 
 beginning of the heat. Other materials, as a rule, are added 
 toward the end of the heat or in the ladle. Ferro-titanium and 
 ferro-vanadium (claimed to have- the property of combining with 
 and removing nitrogen) are put into the ladle after the other 
 additions. 
 
 Following is a general classification: 
 I. Carbon additions : 
 
 1. Pig iron: 
 
 (a) Solid: added in the furnace. 
 
 (b) Molten: added in the furnace or in the ladle. 
 
 2. Coal or coke (crushed): 
 
 (a) In paper bags. 
 
 (b) Fed from a hopper. 
 
 (c) In briquettes. 
 
 3. Contained in other additions (e.g., ferro-man- 
 ganese). 
 
 II. Manganese additions : 
 
 4. Ferromanganese. 
 
 5. Spiegel (usually molten). 
 
 6. Silico-spiegel. 
 
 7. Ordinary pig iron. 
 
394 RECARBURIZING REELING MACHINE 
 
 III. Silicon additions : 
 
 8. Ferro-silicon (10 to 16% silicon). 
 
 9. Ferro-silicon (50% silicon or over). 
 
 10. Carborundum. 
 
 11. Silico-spiegel. 
 
 12. Ordinary pig iron. 
 
 IV. Sulphur additions : 
 
 13. Roll sulphur. 
 
 14. High sulphur pig iron (rare). 
 
 V. Phosphorus additions : 
 
 15. Ferro-phosphorus (up to about 30% phosphorus). 
 
 16. Minerals containing phosphorus (as P 2 O5, part 
 of which is reduced). 
 
 VI. Special additions: 
 
 Chromium, tungsten, etc.; see page 351. 
 
 Recarburizing Additions. See Recarburization. 
 
 Receiver. See Mixer. 
 
 Reciprocal Proportions. Law of: see page 85. 
 
 Reciprocating Mill, Brown's. See page 417. 
 
 Recording Extensometer. See page 471. 
 
 Recording Pyrometers. See page 210. 
 
 Recover; Recovery. See pages 96 and 333. 
 
 Recrystallization; Of Deformed Iron. See pages 122 and 216. 
 
 Recuperation. See page 204. 
 
 Recuperative Furnace. See page 183. 
 
 Red Charcoal. See Charcoal. 
 
 Red Fossil Ore. See page 244. 
 
 Red Hard Sheet. See page 430. 
 
 Red Hardness. See page 446. 
 
 Red Heat. Temperature color: see page 210. 
 
 Red Hematite ; Iron Mine ; Iron Ore ; Red Mine Stone. See page 
 
 243- 
 
 Red Ochre. See page 244. 
 Red Short; Shortness. See Brittleness. 
 Red Short Ore. See page 243. 
 Red Slag Ironstone (Eng.). See page 243. 
 Reduction. (i) In chemistry: see page 88; (2) draft, in rolling: 
 
 see page 407; (3) lowering the amount of a constituent, e.g., the 
 
 reduction of (the percentage of) carbon in a metallic bath. 
 Reduction of Area. See pages 336 and 472. 
 Reduction Ring. See Cold Working. 
 Reed Process. (i) For electrolytic iron: see page 166; (2) for 
 
 pickling, q.v. 
 Reediness (Eng.). In piled iron, a tendency when rolled (into 
 
 plates) to split sideways. 
 Reek (Eng.). To smoke the inside of molds. 
 Reel. A device for coiling up small sections, such as wire, hoop, etc. 
 
 which may be operated by hand or by power. 
 Reeling Machine (Eng.). Cross rolls for straightening: see page 
 
 490. 
 
REESE MILL REFRACTORIES 395 
 
 Reese Mill. See page 419. 
 
 Reese Process. (i) Direct process: see page 145; (2) galvanizing 
 
 process: see page 370; (3) refining process: see page 387. 
 Refined Bar. See page 378. 
 Refined Cast Iron. See page 383. 
 Refined Grain. See page 214. 
 Refined Iron. See page 378. 
 Refined Metal. See page 383. 
 Refined Structure. See page 214. 
 Refiner. See page 316. 
 
 Refinery (Refining) ; Refinery Hearth; Process. See page 383. 
 Refining by Hardening. See page 229. 
 Refining Heat. See page 214. 
 
 Refining Point; Temperature. Critical point: see page 214. 
 Refractory. Capable of withstanding high temperatures without 
 
 fusing or softening. 
 Refractories. Refractory substances are those which possess, at 
 
 least in some degree, the following qualities (Diehl) : 
 
 1. Ability to prevent heat losses through radiation (and con- 
 duction). 
 
 2. Ability to withstand the degree of heat to which they are 
 subjected without altering their chemical or physical relations. 
 
 3. Sufficient hardness to prevent abrasion and yet not spall. 
 
 4. Low coefficient of expansion and contraction. 
 
 5. Inertness to the chemical reactions taking place. 
 
 They are classified, according to their chemical properties, into 
 acid, basic, and neutral refractories. 
 
 Acid refractories. Sand: Consists essentially of silica, 
 SiO>2, and is usually obtained from natural deposits in fine 
 grains, sometimes by crushing or grinding up silicious rocks. 
 It should contain not over 10% of impurities as these tend to 
 make it more fusible, iron oxide and the alkalies being the 
 most undesirable. It is used loose for lining furnaces and in 
 molding. Silicious rocks (firestone, ganister, and sandstone) 
 are composed almost entirely of silica, and may be used, in 
 their natural state, in large pieces or lumps (Eng.) for lining 
 acid converters and cupolas. Their principal application, 
 however, is in the manufacture of silica bricks or Dinas bricks, 
 for which purpose they are crushed and mixed with about i 
 to 2% of lime as a binding material, moistened with water, 
 molded, dried, and then burned (i.e., heated) at a very high 
 temperature, during which they expand lineally about 3%. 
 Bricks thus made are also designated as lime Dinas bricks or 
 English bricks; where clay up to about 10 to 20% is used instead 
 of lime, the bricks are not so good and are termed clay Dinas 
 bricks or German Dinas bricks. Particularly with new or 
 difficult sections, unequal ramming producing a variation in the 
 density of the green brick (before burning), results in cracks 
 (fire cracks) due to unequal expansion when the brick is burned. 
 Fused silica, produced in an electric furnace, is too expensive 
 to use except for certain chemical apparatus. The name 
 ganister was first applied to a variety of sandstone found near 
 
396 REFRACTORIES 
 
 Sheffield, but is now used for any rock very high in silica. 
 Silicious clays or clays, comprising fireclay and loam are hy- 
 drous silicates of alumina resulting from the decomposition of 
 feldspar; pure clay or kaolin has the formula A1 2 O 3 , 2SiC>2, 
 2H2O. If the proportion of silica is higher than this the clays 
 are termed acid or silicious ; if lower, basic or aluminous. 
 Fireclay has low impurities (lime, magnesia, iron oxide, and 
 alkaline oxides), and is not easily fusible. It is used in the 
 manufacture of fire-bricks or fire-clay bricks, which are molded 
 and then burned at a high temperature, during which they 
 shrink lineally about 8%, the amount varying with the nature 
 of the clay. Burnt fireclay is called chamotte (French), scha- 
 mptte (German), and grog (English), and bricks made from it, 
 mixed with a little unburnt clay as a binder, are similarly des- 
 ignated. A brick made with part silica and part chamotte is 
 called half -silica or half -chamotte brick. 
 
 Ball stuff, for repairing acid linings, consists of fireclay mixed 
 with sand or loam and a little water to make it plastic. Loam 
 is a clay containing a higher percentage of silica than fireclay 
 (say over 70%) which makes it somewhat more fusible. Accord- 
 ing to Mellor, clays and shales may be divided into refractory 
 clays which soften above 1500 C. (2730 F.), and non-refractory 
 clays which soften below this. He further classifies the refrac- 
 tory clays into (i) low grade fireclay, softening between 1500 and 
 1650 C. (2730 and 3000 F.); (2) medium grade fireclay, softening 
 between 1650 and 1750 C. (3000 and 3180 F.); and high grade 
 fireclay, softening only above 1750 C. (3180 F.). This softening 
 point is to be determined under standard conditions. A natural 
 substance known as infusorial earth, diatomaceous earth, or 
 kieselguhr, contains a fairly high percentgae of silica (see analysis 
 below); being the skeleton of tiny organisms (diatoms) it is 
 extremely porous, hence most excellent as a heat insulator, but 
 it is not suitable to resist very high temperatures. A similar 
 material found on the Pacific Coast is called celite; it is ground 
 and made into bricks known under the trade name of silocel 
 bricks and used for hot blast stoves, etc. J. W. Richards 
 mentions a material of similar nature found in Jutland, called 
 moler, used for refractory bricks. 
 
 Basic Refractories. Oxides of iron, either natural as ore 
 or artificial as scale or cinder, are rather easily reduced at a 
 high temperature in the presence of carbon, etc., and are also 
 fairly fusible, and hence are employed only when the tem- 
 perature is comparatively low, e.g., for the lining of puddling 
 furnaces and the bottoms of some heating furnaces. Lime 
 and magnesia are obtained almost entirely as the minerals 
 limestone, magnesite, and dolomite. Limestone, CaCOs, 
 when burned (calcined) yields lime, CaO, also called quick- 
 lime or burnt lime, which tends to absorb moisture and car- 
 bonic acid (i.e., to slack or slake) unless kept at a high tem- 
 perature. Except for the bottoms of basic converters (mixed 
 with tar) it is used principally as a flux. Magnesite MgCO 3 , 
 when burned yields magnesia, MgO, which slacks very little 
 
REFRACTORIES 397 
 
 and, next to carbon, is probably the most refractory substance. 
 Its principal use is for making bricks (magnesia bricks or mag- 
 nesite bricks) for which purpose it is crushed, burnt at a very 
 high temperature, then moistened with a little water, molded, 
 and burnt again, a small amount of impurities which it contains 
 acting as the binding material. It may be either massive or 
 crystalline; the former occurs in serpentine and is widely dis- 
 tributed, the most important deposit being probably in Euboea 
 Greece; the crystalline variety is found only in Austro-Hungary 
 where it occurs in the dolomite to which it owes its origin in 
 becoming metamorphosed (Morgenroth). Dolomite, CaMg 
 (COa)2, is widely distributed in this country and hence cheaper 
 than magnesite, practically all of which must be imported. 
 When low in magnesia it is sometimes called magnesian lime- 
 stone. When burnt it does not slack nearly so readily as lime. 
 It is used principally in this country as a lining for basic open 
 hearth furnaces, after crushing, and either calcined or raw; 
 abroad also for basic Bessemer converters, crushed, calcined, and 
 mixed with tar. 
 
 Patented substitutes for regular dolomite or magnesite have 
 recently been placed on the market under various trade names, 
 some typical analyses being given in the table at the end of the 
 article, and certain processes being described below. These 
 substitutes usually consist of some form of magnesian limestone or 
 dolomite rock, which is burned once or twice, and frequently 
 with additions of some form of limestone, such as basic slag. 
 The process for producing magdolite or J. E. Baker's double- 
 burned dolomite is described in the patent papers as follows : Raw 
 dolomite, in lumps 2 to 4" in diameter, is charged in a cupola 
 furnace with alternate layers of coke and, after burning as 
 in ordinary dolomite burning, is crushed and screened through 
 about a %" mesh. The product thus obtained has a considerable 
 percentage of ash, coke, and fines mixed with the good material; 
 it is preferably, without further treatment, subjected to a second 
 burning in a rotary kiln. By subjecting to a temperature of 
 about 2400 F. (1315 C.) the coke and cinder constituents of the 
 mass are consumed, and the finer particles of dust either fused or 
 carried away by the draft. The dolomite granules are subjected 
 to sufficient heat to drive off any volatile matter which may have 
 remained after the first burning, and are rendered much less 
 pervious to moisture. The product is much heavier than dolo- 
 mite obtained by ordinary burning and is more uniform in charac- 
 ter. Syndolag is produced according to the patent papers as 
 follows: Dolomitic limestone is crushed to about %" size, put 
 through a drier, the dust screened out, and the granular material 
 fed through a rotary kiln, under conditions similar to those obtain- 
 ing in the burning of Portland cement. In the kiln the material 
 first passes under the direct influence of a hot flame, where it is 
 raised to a temperature sufficiently high to cause incipient fusion 
 or sintering. This temperature should be around 2800 F. 
 (1535 C.). The sintered granules of dolomite are then cooled 
 in a rotary cooler, and mixed with granulated basic open hearth 
 
398 REFRACTORIES REGENERATIVE CHAMBER 
 
 slag. With a dolomite running 40% magnesia (MgO), a mixture 
 of 90 parts of dolomite and 10 parts of slag works well. Bauxite 
 is a mineral consisting principally of alumina, AlaOs (which should 
 run over 85%), with small amounts of silica, iron oxide, etc., as 
 impurities. It is usually crushed and washed before using but, 
 owing to difficulties in preparation, and its excessive shrink- 
 ing and cracking, it finds practically no employment in the iron 
 industry. It is sometimes made into bricks (bauxite bricks). 
 Neutral Refractories. Chrome iron ore or chrpmite, FeO, 
 Cr2Os, is highly refractory and is generally used in the form 
 of bricks (chrome bricks), ocassionally simply after crushing. 
 It is employed to make a separation between acid and basic 
 linings in the basic open hearth furnace. Carbon is the most 
 refractory substance known. The form known as graphite 
 is found natural or is manufactured in the electric furnace. 
 Only the natural variety is used for making graphite crucibles 
 (see page in). Carbon, usually crushed coke, is also used 
 in the manufacture of clay crucibles. It is sometimes made 
 into bricks (carbon bricks), with pitch or tar as the binding 
 material. A deposit of carbon is found in the bricks forming 
 the lining of blast furnaces which serves to protect the walls 
 from corrosion. Carborundum (silicide of carbon, silicized 
 carbon, silicon carbide), SiC, is manufactured in an electric 
 resistance furnace. Aside from its principal use as an abrasive, 
 it finds some application as a refractory owing to its being almost 
 unaffected by chemical reactions (except in special cases) even 
 at high temperatures. Possessing similar properties is another 
 form called silundum which may be of two varieties, of steel- 
 gray appearance with the formula SiC, and slate-green with the 
 formula Si^O. Silfrax a silicized carbon is also very similar to 
 carborundum, being obtained by the action of vapors of silica 
 or silicon on solid carbon. It is claimed to possess all the chem- 
 ical and heat resisting properties of carborundum and, in addition, 
 great density and toughness. Silit is the name given to material 
 of practically the same nature, which may consist of a mixture of 
 silicon carbide and free silicon, or silicon carbide only, prepared 
 in an electric furnace. Fibrox is the name given to a fibrous 
 material consisting of an oxycarbide of silicon without any defi- 
 nite chemical composition. It is soft and resilient, and has high 
 insulating properties for heat. Vitricarbo is the trade name for a 
 carbonaceous refractory material which contains a vitrifying 
 ash as a binder. (See table of analyses on next page.) 
 
 Refractory Clays. See page 396. 
 
 Refreshment. See page 333. 
 
 Refrigerant; Refrigerating Agent. See page 200. 
 
 Refroidissoir (French). A cooling chamber, e.g., a chamber in 
 which iron sponge, produced by some direct process, is protected 
 from oxidation during cooling. 
 
 Regeneration. (i) Of a cement: see page 67; (2) in heating: see 
 page 203. 
 
 Regeneration Quenching. See page 228. 
 
 Regenerative Chamber. See pages 203 and 310. 
 
REFRACTORIES 
 
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 Regenerative Crucible Furnace. See page 183. 
 
 Regenerative Furnace. See page 183. 
 
 Regenerative Stove. See page 203. 
 
 Regenerator. See pages 183 and 203. 
 
 Regnault Calorimetric Pyrometer. See page 207. 
 
 Regular Cementite. See page 273. 
 
 Regular Coil. See Coil. 
 
 Regular System. Of crystallization: see page 120. 
 
 Regulator Test Piece. See page 70. 
 
 Reheated Carbon. See page 272. 
 
 Reheating. Of steel: see page 232. 
 
 Reheating Furnace. See pages 184 and 377. 
 
 Reichinstein's Theory. Of passivity: see page 364. 
 
 Rejection. Material thrown out on account of defects arising in 
 the course of manufacture. 
 
 Relative Deformation. See page 334. 
 
 Relative Elastic Limit. See page 470. 
 
 Relative Hardness. See page 478. 
 
 Relief Polishing. See page 286. 
 
 Remelting Process. Founding; sometimes a purification process. 
 
 Removable Bottom, Holley's. See page 17. 
 
 Removable Top Furnace. See page 313. 
 
 Reniform Iron Ore. See page 244. 
 
 Rennerfelt Furnace. See page 162. 
 
 Reoxidation. Oxidation of metal which has once been reduced, 
 more especially in connection with the reducing process em- 
 ployed, or immediately after the operation. 
 
 Repeated Stresses. See page 333. 
 
 Repeated Twinning. See page 1 24. 
 
 Repeater; Repeating Mill. See page 416. 
 
 Repetitive Stressing. See page 482. 
 
 Rephosphorization. In any purification process where phosphorus 
 is eliminated and taken up by the slag, and is then partially or 
 wholly reduced again by a reaction, generally with some addition, 
 and reenters the metal. 
 
 Repouring Process. A process in which metal, partially refined in 
 one furnace or vessel, is run into a ladle and then poured into 
 another furnace or vessel to be finished: see page 21. 
 
 Rerolling. See page 419. 
 
 Reservoir. See Mixer. 
 
 Reservoir Cupola. See page 182. 
 
 Residual. Remaining; as the percentage of impurities which are 
 not removed in a purifying process, etc. 
 
 Residual Energy. See page 481. 
 
 Residue Analysis. See page 82. 
 
 Resilience. See page 331. 
 
 Resistance. See page 330. 
 
 Resistance -Arc Furnace. See page 153. 
 
 Resistance Furnace; Heating. See page 153. 
 
 Resistance Pyrometer. See page 208. 
 
 Resistance Weld. See page 503. 
 
 Resisting Moment; Shear. See page 337. 
 
RESISTOR RINGING TEST 40 1 
 
 Resistor. See page 154. 
 
 Resolve. In microscopy: see page 285. 
 
 Resonance Test. See page 483. 
 
 Resquared Plate. See page 433. 
 
 Rest. (i) To allow material to remain without applying any load 
 
 to it or otherwise disturbing it; (2) in a rolling mill; see page 415. 
 Restitution, Coefficient of. See page 478. 
 Restored Steel. See page 226. 
 Resulphurization. The. reabsorption of sulphur by metal from 
 
 which it has been removed, usually in the same process. 
 Retained Carbon. In hardening: see page 279. 
 Retardation. (i) In the cooling of alloys: see page 264; (2) of 
 
 corrosion: see page 364. 
 Retarded Coke. See page 97. 
 Retarded Combustion. See page 202. 
 Retention Theories. Of hardening: see page 279. 
 Retentive. Able to hold, i.e., prevent subsequent removal, as of 
 
 slag with regard to phosphorus. 
 
 Reticular Structure; Reticulated Structure. See page 126. 
 Retort Coke. See page 95. 
 Retort Furnace. See page 184. 
 Retort Oven. 'See page 96. 
 Returns (Eng.). Material rejected by customers. 
 Reverb eratory Furnace. See page 182. 
 Reversed Mold. See page 300. 
 
 Reversible Alloy ; Process ; Transformation. See pages 265 and 327. 
 Reversing Class. In hardening: see page 279. 
 Reversing Mill. See page 408. 
 Reversing Overstrain. See page 282. 
 Reviving (obs.). Producing (reducing) metal from its ores or from 
 
 its oxidized condition. 
 Revolving Screen. See Screen. 
 Revolving Top. Of a blast furnace; see page 32. 
 Rewelded Pipe. See page 490. 
 Rhabdite. See page 292. 
 Rhombic Sulphur. See Sulphur. 
 Rhombic System. Of crystallization: see page 120. 
 Rhombohedral Cleavage. See page 124. 
 
 Rhombohedral (-ic) System. Of crystallization; see page 120. 
 Riband (Eng.). Ribbon or band. 
 Rich; Richness. Of pig iron; high in silicon. 
 Rich Iron. See page 343. 
 Riddle. In molding; see page 301. 
 Rider. (i) In a rolling mill: see page 406; (2) of a testing machine: 
 
 see page 469. 
 
 Riemer Hot Top Process. See page 61. 
 Riepe Process. See page 380. 
 Rifled Pipe. See page 490. 
 Rigidity. See page 330. 
 Ring. (i) In blast furnace practice: see page 35; (2) in cold 
 
 drawing; see page 101. 
 Ringing Test. See page 483. 
 
 26 
 
402 RINSING BATH ROLLING 
 
 Rinsing Bath. See page 507. 
 
 Rinton Process. See page 145. 
 
 Ripper; Ripping Block. In wire drawing: see page 508. 
 
 Riser. Of castings: see pages 56 and 299. 
 
 Rising Casting. See page 57. 
 
 Rising Gate. See page 299. 
 
 Rising Head. See page 56. 
 
 Rising Steel. See page 55. 
 
 Riveted Pipe. See page 489. 
 
 Roach Belly Core. See page 299. 
 
 Roak. See Seam. 
 
 Roasted Red Mine (Eng.). Roasted hematite. 
 
 Roasted Steel. See page 226. 
 
 Roasting. (i) In briquetting; see page 44; (2) see Ore. 
 
 Roasting Heap; Mound; Pile. See page 181. 
 
 Robert Converter. See page 24. 
 
 Roberts-Austen Equilibrium Diagram. See page 272. 
 
 Roberts-Austen Recording Pyrometer. : See page 210. 
 
 Robertson Process. See page 492. 
 
 Robin's Reagent. For etching; see page 287. 
 
 Rochussen and Daelen Process. See page 22. 
 
 Rock Sand (Eng.). The debris of abraded rock. 
 
 Rock Wool. See Slag Wool. 
 
 Rod. Generally understood to be a round bar. Standard wire 
 rods are round bars having a section 0.2 to 0.3" diameter, which 
 are coiled in bundles. U. S. Government limits size of wire rods 
 to No. 6 B. W. G. or 0.203", an d if smaller than this: wire. 
 
 Rod Casting Process. See page 65. 
 
 Rod Mill. See page 415. 
 
 Rodney (Eng.). See page 377. 
 
 Roebling Gage. See page 187. 
 
 Roechling-Rodenhauser Furnace. See page 162. 
 
 Roger Process. (i) Direct process: see page 145; (2) for sulphur 
 prints: see page 288. 
 
 Rohl's Reagent. For etching; see page 287. 
 
 Rohnitz Process. See page 78. 
 
 Roke (Eng.). See Seam. 
 
 Rolls. See page 403. 
 
 Roll-Knobbling. See page 369. 
 
 Roll Mark. See page 405. 
 
 Roll Scale. See Scale. 
 
 Roll Table. See page 407. 
 
 Roller. (i) The man in charge of a rolling mill: see page 430; (2) 
 a metal cylinder mounted on a shaft which is driven (live roller) 
 or is not driven (idle roller or idler), for transporting pieces of 
 steel, etc. When a live roller is broken it is called a dead roller. 
 
 Roller Pot. In coating sheets, a vessel filled with molten metal 
 through which the sheets are drawn by means of several pairs 
 of rolls. 
 
 Roller's Side. See page 415. 
 
 Rollet Process. See page 387. 
 
 Rolling; Rolling Mills. Rolling is the operation of reducing 
 
ROLLING 
 
 403 
 
 the section of pieces of metal by passing them between revolv- 
 ing cylinders termed rolls. A rolling mill consists essentially 
 of the rolls set in a suitable framework to support them, called 
 housings, standards (Eng.), or holsters (Eng.), and connected 
 with the engine by pinions and spindles as will be described 
 later. 
 
 Rolls. These consist of (a) a middle portion called the 
 body or barrel which comes in contact with the piece being 
 rolled; (&) the ends which rest in the bearings, called necks, 
 journals, or rarely spindles, which are always of smaller diameter 
 than the middle portion to permit the rolls to come close to- 
 gether; and (c) the portion at the fillet connecting the body 
 
 PIG. 54. Pair of rollers by Messrs. Akrill & Co., Ltd., West 
 Bromwich for rolling rails. AA, bodies of the rolls; B, B, B, B, 
 necks which revolve in bearings in the chocks; C, C, C, C, wobblers, 
 by means of which the rolls are driven. The openings between 
 the bodies of the rolls from the passes, consisting of the grooves 
 a, a, bounded on each side by a collar, b, b, and closed in at the top 
 by the closers or formers, c, c. 
 
 and the necks, called the shoulders. Rolls are practically 
 always cast, almost never forged (steel rolls), to rough shape 
 and then turned down to the exact size. On account of the 
 greater hardness, cast iron is generally employed for finishing 
 a piece; if cast in a chill (iron) mold to make the surface por- 
 tion as hard and smooth as possible it is called a chill (chilled) 
 roll; if not chilled, a grain roll; if only part of the barrel is chilled, 
 a part chill roll. Steel rolls are always cast in sand without 
 any chilling effect and are subsequently annealed to break up 
 the coarse crystallization produced by slow cooling. They 
 are softer than cast iron, hence are sometimes termed soft 
 rolls, and are used for the preliminary working or roughing, 
 
404 
 
 ROLLING 
 
 or where a very smooth surface on the piece is not required. 
 If the barrel is perfectly smooth, as for the production of plates, 
 it is termed a plain roll or flat roll. Where material of uneven 
 section is to be produced, such as beams or angles, the rolls 
 are cast with depressions or grooves and raised portions or 
 collars to correspond (grooved rolls). A half roll has only 
 
 FIG. 55. Typical American housing. (Harbord and Hall, Met. 
 of Steel.) 
 
 half of the barrel grooved; this is generally only in a three-high 
 mill where the grooved halves of the top and the bottom roll 
 are at opposite ends, the whole of the middle roll being grooved. 
 Hollow rolls are those (a) which have a hole passing through 
 them or (b) which are worn or turned slightly concave in the 
 middle. The rolls while in use are usually sprayed with water 
 
ROLLING 
 
 405 
 
 to prevent them from becoming overheated, which causes cracks 
 on the surface, termed water cracks, heat cracks, or fire cracks, 
 as these produce on the surface of the piece slight elevations 
 or roll marks which, in the case of small sections, may become 
 rolled over, giving a defect called a lap. Rolls which are cracked 
 to any extent are turned smooth (dressed) in a lathe. 
 
 A pass is the opening between a pair of rolls formed by cor- 
 responding grooves or collars. A closed pass, box pass, or 
 box groove is formed by a groove in one roll with a collar on 
 each side, and fitting into this opening a raised portion on 
 the other roll called a former or closer. An open pass con- 
 sists of a groove or grooves without adjacent collars. A blind 
 
 FIG. 56. Pinions and coupling boxes. 
 
 pass or false pass occurs in a three-high mill where there is 
 no pass in the top (or bottom) roll corresponding to the groove 
 in the bottom (or top) roll complementary to that in the middle 
 roll. Passes are named according to the section they produce: 
 gothic pass (like a double gothic arch); diamond pass; oval 
 pass; convex pass; belly pass or bellied pass. A live pass is 
 one in which the piece is worked, and a dead pass is the reverse. 
 
 Pass is also the term used for the travel of the piece of metal 
 being worked, once between the rolls. It is called a lost pass 
 in the case of a two-high non-reversing mill when the piece is 
 returned to the original side over the top roll, during which 
 it receives no work. 
 
 The housings are cast of cast iron or, better, for heavy work, 
 
406 ROLLING 
 
 of steel. They are secured to massive foundations so they 
 will be perfectly rigid. They kick in when the tops incline 
 toward each other. Each housing looks like an elongated 
 letter "U" set upright, the open space being large enough 
 for the necks of the rolls resting in suitable bearings or brasses, 
 which in turn are held in place by chucks or chocks. The 
 chuck on the top of a lower roll which supports the chuck or 
 bearing of the roll above is sometimes termed a carrier. The 
 chuck or cap over the top roll, against which the housing screw 
 rests to keep the roll in the desired position when the piece 
 is going through, is called the rider. In a two-high mill, when 
 the top roll is adjusted for every pass, this is raised by rods 
 resting against the bearing from below and forced up by a 
 counterweight hung on a lever arm (balanced roll), or by hy- 
 
 FIG. 57. Pinions and spindles. 
 
 draulic means. Across the top of the housing is a cap (housing 
 cap) through which passes the housing screw or pin (Eng.) 
 to force the roll down and keep it in the proper position. This 
 screw is operated by a hand lever (spanner) for three-high 
 shape or bar mills, or mechanically for two-high mills when the 
 top roll must be adjusted for each pass. In the latter case 
 the distance between the rolls is indicated on some form of 
 gage. Sometimes, with a three-high mill, to prevent the top 
 roll from bending, a girder or bar may be fastened across the 
 tops of the housings, giving the middle of the roll an additional 
 bearing; this is called a stiff ener. A set of rolls and the housings 
 which hold them are called a stand, and two or more stands 
 connected together constitute a train. 
 
 One end of each roll, or both if there is more than one stand 
 in the mill, is given a cruciform or other section to fit a corre- 
 
ROLLING 407 
 
 spending opening in the coupling box by which it is connected 
 with the spindle in a similar manner, and this again to the pinion 
 and the engine. The end of a roll (or spindle or pinion) which 
 has this section is called the wobbler (or wabbler). The spindles 
 are like large pieces of shafting and connect the rolls with the 
 pinions, or the rolls in one stand with those in another; they 
 have wobblers on the ends similar to those on the rolls. In 
 some cases a spindle is designed to break if the piece sticks in 
 the rolls, to save the latter, and is then termed a breaking 
 spindle. The pinions are gears which transmit the power to 
 the rolls. They somewhat resemble short rolls with teeth 
 cast on the barrel, and provided at the ends with wobblers. 
 The pinions are also supported in housings (pinion housings). 
 The jack shaft is the one which takes the power from the engine 
 shaft and transmits it by the pinions and the spindles to the 
 rolls. In some cases it is known as the main spindle or leading 
 spindle. The manner in which the power is supplied by the 
 engine varies according to the size and the type of mill. If 
 the spindle or shaft is driven directly by the engine shaft, by 
 means of a casting bolted on, known as a crab, the mill is direct 
 driven, while if gears are interposed either to reduce or in- 
 crease the speed (almost always the former), it is gear driven. 
 With small mills the driving may be done by a belt or a rope, 
 and these are belt driven and rope driven respectively. If a 
 motor is employed the mill is electrically driven. 
 
 If small sections are being rolled the pieces may be handled 
 by hand, but those' which are too heavy are supported on a 
 series of rollers on each side of the rolls, such a set being known 
 as a table or roll table. If these are not driven they are termed 
 idle rollers or idlers; if driven, live rollers; if one of the latter 
 becomes broken, a dead roller. Underneath the rolls a pit 
 is usually provided to catch the scale which comes from the 
 piece, and called a scale pit. 
 
 The piece of metal being rolled is usually referred to as the 
 piece. The amount by which it is reduced in section for a 
 given pass is palled the reduction or draft (draught). When 
 the piece enters the rolls, the angle determined by the lines 
 drawn from the center of one of the rolls (a) to the point on 
 the circumference which the piece first touches, and (6) to 
 the center of the other roll, is called the entering angle or angle 
 of contact, and must in general be less than 30 or otherwise the 
 rolls will not bite, i.e., be able to seize the piece and draw it 
 through. To assist in this, a little sand is occasionally put on 
 the end of the piece, or where marks on the surface of the piece 
 are not objectionable the rolls are chipped out, called ragging, 
 roughing, or cogging, whereby a better grip is obtainable. 
 From experiments it would appear that the rolls exert a squirt- 
 ing action on the piece, i.e., the piece on leaving the rolls is 
 traveling faster than the circumference of the rolls. The dif- 
 ference in rate will vary with the thickness of the piece, the 
 diameter of the rolls, and the amount of draft. In practice, 
 in arranging the successive speeds of the sets of rolls in a tandem 
 
408 ROLLING 
 
 continuous mill all these factors must be taken into considera- 
 tion. "If there are four such stands of rolls, each effecting a 
 25% reduction, and the first rolls are driven at 64 revolutions 
 per minute the others will have approximately the respective 
 speeds of 80, 100, and 125. Creeping is the difference in rate 
 between different parts of the piece passing through the rolls. 
 If the sides of the piece are not supported by grooves, collars, or 
 supplementary rolls set at right angles to the others, the width of 
 the piece is slightly increased, and this is called the spread. The 
 extension takes place in the direction in which the piece is travel- 
 ing. If the rolls are horizontal the thickness of the piece will be 
 reduced, while the width will be slightly increased; with vertical 
 rolls, the width will be reduced and the thickness somewhat 
 increased. Consequently, if both the thickness and the width 
 are to be reduced, it will be necessary either to (a) turn the 
 piece 90, or (b) employ both horizontal and vertical rolls. In 
 rolling flat material it is usually customary to give it one pass 
 vertically, toward the end of tjie operation, to insure having 
 the width right, called an edging pass. The operation of 
 rolling a piece down to a smaller section is sometimes termed 
 (Eng.) rolling off or bolting. 
 
 The earliest type of rolling mill consisted of two plain hori- 
 zontal rolls superimposed, which were revolved continuously 
 in one direction, hence, when the piece had been given one 
 pass, and before it could be given another, it was necessary to 
 bring it back to the side of the rolls on which it had started. 
 To do this it was laid on top of the top roll, and so carried back, 
 of course without receiving any work. This type is called a 
 pull over or pass over mill and is still employed practically 
 exclusively in the sheet and tin plate industry. George Fritz 
 improved on this by placing a third roll on top and rotating 
 it in the same direction as the bottom roll, so the piece would 
 be worked between the top and the middle roll on the way 
 back. This is called a three-high mill (rarely a Fritz mill) 
 and the former type a two-high mill; German designations for 
 them are respectively trio mill and duo mill. With the three-high 
 mill, since the ingot or piece must be raised or lowered for 
 each pass an amount equal to the diameter of the middle roll, 
 the tables must provide .for this by being raised or lowered 
 by hydraulic means (lifting table), or else must be pivoted in 
 the middle and arranged with gears so the end nearest the rolls 
 can be sufficiently raised or lowered (tilting table). The former 
 type is generally used for blooming mills, the latter for plate 
 and shape mills. In the case of two-high mills the tables are 
 stationary, i.e., do not move up or down. 
 
 R. M. Daelen devised a mill with both vertical and hori- 
 zontal rolls so that all four sides of a piece could be rolled in 
 one operation without the necessity for turning it over, and 
 this is termed a universal mill (Daelen's universal mill). Rams- 
 bottom built a mill with two rolls which could be rotated in 
 either direction, thereby avoiding the use of three rolls run 
 continuously in one direction. This is called a reversing mill 
 (Ramsbottom's reversing mill), the other a non-reversing mill. 
 
ROLLING 409 
 
 The first grooved rolls were introduced by Henry Cort (Cort's 
 mill), and were used for rolling plain rectangular pieces, but 
 were easily modified to produce various irregular sections. 
 When used for small pieces such a mill is called a bar mill or 
 merchant mill, while for large sections, such as beams, it is 
 known as a shape mill (in England, a section mill). In this 
 country, bar and shape mills are nearly always three-high, or 
 in stands of two-high, non-reversing, on the continuous or 
 semi-continuous principle which will be considered later; abroad 
 they are frequently two-high: for large sections reversing, 
 and for small sections of either the reversing or the non-revers- 
 ing type. The types just described are those at present in use, 
 recent improvements consisting in the arrangement of the stands 
 and the method of driving the rolls. Thus there may be a 
 number of stands arranged end to end, called a train; the stands 
 may be arranged one in front of the other called a tandem 
 continuous mill; or there may be several combinations of the 
 first two. There are also several patented mills which will be 
 described farther on. 
 
 CLASSIFICATION OF ROLLING MILLS 
 
 I. Mills which depend upon the arrangement and the 
 rotation of the rolls : 
 
 1. Two horizontal rolls: two-high: 
 (a) Reversing: 
 
 (i) Top roll adjustable: 
 
 Blooming, cogging, slabbing, plate, (for- 
 eign), 
 (ii) Both rolls fixed: 
 
 Shape. 
 
 (&) Non-reversing: pullover: 
 (i) Top roll adjustable: 
 Sheet and tin plate. 
 (ii) Both rolls fixed: 
 
 Merchant mills (foreign). 
 
 2. Three horizontal rolls : three-high; non-reversing: 
 
 (a) All three rolls fixed: 
 Shape, merchant, bar. 
 
 (b) Top roll adjustable, middle roll movable: 
 Plate (Lauth) ; blooming. 
 
 3. Universal mill: 
 (a) Reversing: 
 
 (i) Two horizontal and two vertical rolls: 
 Slabbing; plate; shape (Grey, Sack, etc.). 
 
 (ii) Two horizontal rolls and two sets of ver- 
 tical rolls (two each), one at each side of 
 the horizontal rolls: 
 Plate. 
 (6) Non-reversing: 
 
 Three horizontal rolls, and either one or two 
 
 sets of vertical rolls as above: 
 
 Plate. 
 
410 ROLLING 
 
 II. Mills which depend upon the arrangement of the 
 stands. 
 
 1. Two or more stands end to end in one line: train: 
 
 (a) Reversing, two-high (foreign) : 
 Plate ; shape. 
 
 (b) Non-reversing: 
 
 (i) Two-high: 
 
 Sheet and tin plate, 
 (ii) Three-high: ' 
 
 Shape ; bar or merchant. 
 
 2. Two or more stands one in front of the other: 
 Two-high, non-reversing: 
 
 Continuous ; Morgan continuous ; Bedson con- 
 tinuous. 
 
 3. Combinations of trains and continuous: 
 
 (a) Two or Inore trains usually staggered: there 
 may be one stand alone, but all rolls are of 
 the same size: 
 
 Shape; rail; merchant. 
 
 (b) One train of small rolls, with stand of larger 
 rolls in front for roughing: 
 
 Tandem roughing or Belgian (for small sec- 
 tions). 
 
 (c) Two or more stands tandem, and one or more 
 trains staggered: 
 
 Garrett semi-continuous; Morgan semi-con- 
 tinuous. 
 
 III. Mills for special' products, or in which there is no 
 reduction : 
 
 1. No reduction: 
 
 (a) Slitting mills. 
 
 (b) Tube mills ( welded). 
 
 2. Reduction or change of form: 
 (a) Tire and wheel mills. 
 
 (6) Mills for seamless tubing: 
 (i) Piercing, 
 (ii) Rolling. 
 
 IV. Mills based upon the nature of their product : 
 
 1. Semi-finished: Roughing: 
 
 Blooming; billet; cogging; slabbing; muck 
 bar. 
 
 2. Finished: Finishing: 
 
 Shape; plate; rail; bar or merchant; hoop; 
 cotton tie ; etc. 
 
 The size or rating of a rolling mill for everything but plates 
 is based upon the pitch diameter of the rolls, which in case the 
 rolls are of exact (nominal size) is the distance between their 
 centers. The measurement, however, really is based on the 
 distance between centers of the pinions, on account of the varia- 
 tions in the size of rolls due to turning or allowance for turning; 
 
ROLLING 411 
 
 for example, a 30" blooming mill or a 16" bar mill. In the case of 
 plate mills the size has to do with the width of plate which can be 
 rolled, which in turn depends upon the type of mill. Thus a 48 * 
 universal mill (where the edges are rolled) can produce finished 
 plates up to 48" wide; a 140" sheared mill indicates that the 
 length of the barrel of the rolls is 140", but on account of the 
 danger to the mill of having the plate project beyond this, the 
 extreme width as rolled will be about three or four inches less than 
 this; and in addition, a certain allowance (about four to eight 
 inches), varying with the thickness and the length of the plate, 
 must be made for side shearing. 
 
 Product. In using large ingots, or where the product is 
 very small in size, it is generally the practice to roll down par- 
 tially on one mill, and finish on another. These two classes 
 are termed respectively semi-finished products (semi-products) 
 and finished products. Semi-finished products are divided 
 into (i) blooms and billets, the names being more or less inter- 
 changeable, both being rectangular in cross-section, and square 
 or nearly so; in general billets are considered as having a cross- 
 section of from 4 up to 36 square inches, the width never being 
 equal to twice the thickness; smaller sizes are usually classed 
 as bars, but in certain cases are termed small billets; blooms 
 is the name applied when the cross-section is greater than 36 square 
 inches. (2) Slabs are rectangular pieces to be rolled down into 
 plates (they may be considered as very heavy plates), where the 
 width is at least equal to twice the thickness. (3) Sheet bars or 
 tin bars are small slabs used for making sheets and tin plates; if 
 made of charcoal wrought iron they are termed charcoal bars; 
 ordinary sheet bars are called coke bars. 
 
 Mills for semi-finished products. Billets, blooms, small 
 slabs, and sheet bars are produced oh a mill called a billet 
 mill, blooming mill, or cogging mill. The first two names are 
 used in this country, more particularly where the product 
 is not used directly in some finishing mill, the last name being 
 sometimes used to cover this case; in England cogging mill is 
 used for all. The ordinary style of mill consists of one stand 
 of rolls, either two-high or three-high, about 30" to 40" in diam- 
 eter. The rolls are divided into passes of different widths by 
 collars, and are usually ragged, at least for the first few passes; 
 they are called blooming rolls or billeting rolls. The ingots 
 used generally weigh from about 4000 up to 8000 Ibs. or over, 
 and, as it is necessary to turn them 90 after every few passes, 
 a mechanical device must be employed which is called a manip- 
 ulator (rarely a tilter). With a three-high mill it usually 
 consists of a framework mounted on wheels so it can be moved 
 backward and forward under the roll table. It has vertical 
 projections called fingers or tappets which, by lowering the 
 table, will pass up between the rollers and catch the ingot near 
 the edge and thereby force it over. By lowering the table 
 sufficiently the ingot will rest on the carriage, between the 
 fingers, which can then be moved so as to bring the piece in 
 front of the pass it is to enter. In the case of a two-high mill, 
 
412 ROLLING 
 
 where the tables are stationary, the manipulator must be capa- 
 ble of movement in a vertical as well as a horizontal direction; 
 by certain arrangements vertical movement may not be neces- 
 sary. Turning a billet over 90 for the last pass to remove 
 any fin is sometimes called curing (Eng.). A piece which twists 
 on its axis when entering the rolls is sometimes said to turn 
 down; as a result the piece is not a true rectangle in cross- 
 section and is said to be rolled diamond. 
 
 Another type of mill for small billets and sheet bars is the 
 continuous mill with rolls about 12" to 16" in diameter. This 
 consists of a number of stands of two-high, non-reversing rolls, 
 one behind the other, which are driven at progressively increas- 
 ing speeds. In some arrangements, the last or finishing stand, 
 placed at a little distance from the others, is called the bull 
 
 FIG. 58. Shape roll (top) blooming roll (bottom). 
 
 head. To work all sides of the piece one of two arrangements 
 is necessary: in the Bedson continuous mill the rolls in succes- 
 sive stands are alternately horizontal and vertical, or else set 
 at an angle of 45 alternately to the right and the left. In 
 the Morgan continuous mill all the rolls are horizontal, and 
 the piece is turned or twisted by special guides (twisted guides) 
 which look something like a bell open at both ends, and with 
 a spiral or angular groove cut in them. 
 
 With the ordinary type of blooming mill first described the 
 ingot is rolled out into one piece which is subsequently cut up 
 by shears, consisting of two knife blades, one fixed and one 
 movable, the latter actuated by gearing from a steam engine 
 (steam shears) or motor (electric shears), or by a hydraulic 
 cylinder (hydraulic shears); if the blades are set at a slight 
 angle (rake) to each other it is termed a guillotine shears. In 
 
ROLLING 413 
 
 the case of continuous billet mills the lengths obtained are so 
 great that the length of the tables would be excessive if the 
 shearing were not done until the entire piece had been rolled. 
 Hence a special type of shears has been devised (Edwards' 
 flying shears). This cuts the piece while it is issuing from the 
 last stand, and is operated by two steam cylinders, one of which 
 brings the knife down on the piece, while the other, immediately 
 afterward, throws the knife outward so it will not interfere with 
 the progress of the remainder. It is operated by a trigger which 
 is set for the desired length, and is sprung by the piece itself 
 striking it. 
 
 Slabbing mills may be considered as heavy plate mills, and 
 are usually of the two-high, universal type, sometimes pro- 
 vided with a manipulator for turning the ingot. The rolls 
 are about 30" in diameter and are smooth (without any ragging) 
 as all precautions must be taken to prevent scale from being 
 rolled into the surface of the piece, as this would cause a bad 
 surface on the finished plate. Muck mills are the mills used 
 in connection with puddling for rolling the puddle balls, after 
 squeezing, into rough bars (muck bars). They are usually 
 three-high (rarely two-high, pull over) with rolls from about 
 1 8" to 24" in diameter. 
 
 Mills for finished products. These may be divided into 
 plate mills and shape mills, for large sections, and bar mills 
 or merchant mills for small sections. On them slabs, billets, 
 or blooms are rolled down into finished material. The term 
 merchant mill was first used in connection with the manufac- 
 ture of wrought iron to distinguish the mill or train on which 
 the material was finished ready for sale from the muck train 
 or forge train (forge rolls or puddle train) which rolled the 
 puddle balls after squeezing or shingling into muck-bar: the 
 term has been retained to designate a mill on which small sections 
 are rolled. 
 
 Plate mills are divided into sheared plate mills where the 
 edges are not rolled and must be sheared off (side shears); 
 and universal mills where the edges are rolled and hence only 
 the ends need be cut (end shears). The size of sheared mills 
 is about 60" to 200", and of universal mills, about 18" to 48". 
 The universal mills are nearly all two-high, reversing, with 
 two sets of vertical rolls, one on each side of the horizontal 
 rolls. They may roll slabs or slab ingots (wide flat ingots). 
 In this country and on the Continent, nearly all the sheared 
 mills are three-high, non-reversing, but in England the prefer- 
 ence is for two stands of two-high, reversing rolls, one stand 
 for roughing and the other for finishing; slabs are generally 
 rolled. The barrels of the rolls are smooth, and as soon as 
 they become rough must be dressed (turned down) . In Germany 
 there is a modification where the rolls have collars for producing 
 plates of narrow width, very similar to the bar mills used 
 elsewhere for the purpose. With universal mills the slab or ingot 
 is rolled back and forth until the desired gage (thickness and 
 width) is obtained. With sheared mills this practice may be fol- 
 
414 ROLLING 
 
 lowed or else, with narrow slabs, the rolling may proceed until the 
 length of the slab has been increased sufficiently for the width of the 
 plate, when it is swung around 90 by hooks suspended from over- 
 head beams. In the first case the plate is said to be rolled 
 longitudinally, in the second case, transversely (in England called 
 spreading and turning). Rolling transversely, particularly semi- 
 finished material, is also called cross rolling. It is claimed to 
 effect almost complete elimination of seams and surface defects 
 in the case of billets or slabs. The type of three-high mill used 
 in this country is called the Lauth mill, the special feature being 
 the middle roll which is about two-thirds the diameter of the 
 other rolls. This smaller roll gives greater kneading action to the 
 piece. The bottom roll is fixed in its bearings, but the height of 
 the top roll is adjustable by means of the housing screws which 
 are regulated by a man called the screw down. The middle 
 roll rests against either the top or the bottom roll to stiffen 
 it, depending upon the direction in which the piece is traveling. 
 There is bound to be a certain amount of spring in the rolls, even 
 when supported, particularly when rolling wide plates and this 
 together with the greater wear or channeling of this portion of the 
 rolls causes the plates to be thicker in the middle than at the 
 edges; the amount above the theoretical or normal thickness is 
 known as the crown of the plate. After rolling, the plates are 
 made flat by passing through straightening rolls which consist of 
 a series of upper and lower rolls staggered. The tables on which 
 the plates are taken to the shears and allowed to cool are called 
 cooling tables, cooling beds, or hot beds. 
 
 Shape mills. In this country they are usually composed 
 of several stands of three-high rolls in one or more trains. The 
 first stand is called the roughing stand or roughing rolls (rarely 
 roughing rollers, rough rollers, breaking down rolls, bolting 
 down rolls), the last, the finishing stand or finishing rolls, 
 and those between, strand rolls. The problem of designing 
 the successive passes in the rolls to produce the desired section 
 is one requiring great experience and skill. In rolling sections, 
 such as beams and channels, on an ordinary three-high mill, 
 since different parts of the rolls have different diameters corre- 
 sponding to the section, there is always a certain amount of 
 tearing action going on which appears to effect horizontal 
 as well as vertical reduction, but is not true rolling. The 
 smaller parts of the section which have to be as long as the 
 larger ones are said to be drawn. To reduce this tearing action 
 as far as possible, and more particularly to provide clearance 
 for the rolls, the flanges of a channel, beam, etc., must be tapered. 
 With ordinary methods the flanges cannot be very high as the 
 deep grooves required would make the rolls too weak, and also the 
 metal would become too cold to penetrate to the bottom or, as it 
 is commonly expressed, the section would not be filled out. 
 Adjusting the rolls to produce a section of the proper gage and 
 weight is called lining the rolls; when a heavier section is required 
 the rolls must be separatd slightly (lining up), and thin metal 
 strips (liners) are inserted between the bearing blocks; for lighter 
 
ROLLING 415 
 
 sections the rolls are lined down by removing one or more of these 
 strips. 
 
 Guides and guards. To avoid delays in inserting the piece 
 in the right pass, two pieces of metal, called guides, are fastened, 
 one on each side of the pass on the entering side of the rolls, 
 to rods extending across the rolls. These pieces diverge at 
 their outer ends so it will be easy to introduce the piece, the 
 inner ends which nearly touch the rolls converging so the distance 
 between them is the same as the width of the pass. Particularly 
 in rolling shapes, the piece, instead of coming out flat, may stick 
 to one of the rolls and become wrapped around it, an action 
 known as collaring. Any piece which does this, or has become so 
 bent or twisted it cannot be finished, is termed a cobble. To 
 prevent this as far as possible guards or stripping plates are placed 
 at the top and the bottom of a pass on the issuing side; the inner 
 side is tapered and rests on the rolls. The bottom guard is 
 usually bolted to a rod running across the rolls while the top one 
 is hung on a similar rod and held in place by a counterweight, 
 and is called a hanging guard (rarely a yielding guard or clearer). 
 In connection with the roughing rolls for muck bar, pieces called 
 scrapers are sometimes employed, which are similar to guards, 
 but placed slightly above, to scrape off any pieces of iron which 
 fall from the bloom or which stick to the roll. 
 
 Bar mills, also called merchant mills or, on account of the 
 special product which they make (but to which they are not 
 necessarily restricted), rod mill, hoop mill or strip mill, cotton 
 lie mill. As a rule they are of the three-high, non-reversing, 
 or of the two-high, continuous type, and the sections rolled 
 rarely exceed 3" square. The simplest type is where there are 
 a number of stands in train, all the rolls being of the same size. 
 With six such stands they are designated as follows: 
 
 ist stand (three-high) roughing stand (roughing rolls). 
 
 2d " " pony roughing stand. 
 
 3d " first strand. 
 
 4th second strand. 
 
 5th " (two- or three-high) planishing rolls. 
 
 6th finishing stand or chilled rolls. 
 
 The side of the mill on which the piece first enters is some- 
 times called the roller's side, and the opposite, the catcher's 
 side; these terms are generally restricted to pull over mills, 
 such as those described under Sheets and Tin Plate. Fore 
 plate is the name sometimes applied to a plate at the bottom 
 of and connecting the two housings;. it is supported by cramp 
 bars to which the guides and guards are fastened. Rests 
 are pieces placed before the rolls and just below the top of 
 the lower roll upon which the bloom or bar may be rested while 
 being pushed into the rolls. A feed roll is a small driven roll 
 sometimes placed immediately in front of a stand of rolls to 
 facilitate the introduction of the piece. Pinch rolls are for the 
 same purpose as the preceding, and consist of two small driven 
 
41 6 ROLLING 
 
 rolls which grip the piece just tightly enough to carry it into the 
 rolls. 
 
 To increase the speed of rolling and so permit greater lengths 
 to be rolled, instead of simply passing the piece backward 
 and forward through the rolls (i.e., the end which is the first to 
 enter the rolls on one pass is the last to enter on the next), 
 when the piece is sufficiently reduced in section the end issuing 
 from the rolls may be bent around and inserted immediately 
 in the next pass (looping), and in this way a piece may be in 
 two or three passes at the same time; where this is done the 
 mill is called a looping mill. With the smaller pieces it is neces- 
 sary to enter them by hand, but with those of intermediate 
 or larger size labor-saving devices known as repeaters or turn- 
 overs are frequently " employed. With the intermediate sec- 
 tions these consist of a vertical curved guide with a driven 
 roller at some distance from the rolls which serves to bring 
 the end around and return it to the rolls for the next pass; in 
 the Morgan semi-continuous mill (also called a repeating mill) 
 
 - this is effected by curved grooves cast in the heavy iron plates 
 forming the floor or bed of the mill. 
 
 Hand mill and guide mill. These are the two forms of an 
 ordinary bar mill. In both the piece is handled by men with 
 tongs. In the case of the hand mill for the last pass the piece 
 must be entered in the right position and, if necessary, held 
 with the tongs to prevent it from turning, and, when rolling 
 rounds, the piece must be put through the last pass about three 
 times, being turned each time 90 to insure a true section. In 
 a guide mill, which is generally of small size, at least the last 
 pass is provided with a closed guide. This is a bell-shaped 
 tube, the outward end, into which the end of the piece is thrust, 
 having a pronounced flare, and the other end, which is as close 
 to the rolls as possible, having a hole just the shape of the piece 
 in order to hold it in the right position and prevent it from 
 turning or twisting when gripped by the rolls. This second 
 type of mill requires only one pass through the finishing pass, 
 and is very generally used for rolling small sections such as hoop, 
 etc., where the speed of the rolls is great. In certain districts 
 a mill operated by hand without closed guides is called a hand 
 guide mill. A guide roll (Eng.) is the smallest size used in an 
 iron works, and is employed in the production of the smallest 
 sections which are only one size thicker than wire rods (Turner). 
 
 To enable the finishing rolls to be driven at a higher speed 
 than the roughing, and also to be able to handle a larger billet, 
 
 one stand of roughing rolls of larger diameter, driven independ- 
 ently, is sometimes placed in front of and ,a short distance away 
 from the first stand of the regular train. This arrangement 
 is termed a Belgian mill or a tandem roughing mill. 
 
 The AlUs-Andrew process for rolling very thin sheets or 
 strips consists in coating a number of strips with a composition 
 to prevent them from sticking, and riveting them together at 
 one end. They are then heated and rolled down on the principle 
 of a pack of tin plates. '* 
 
ROLLING 417 
 
 G. Balthasar's universal mill for rolling bars consists of a 
 pair of horizontal and a pair of vertical rolls so arranged that 
 any groove of the horizontal rolls may be brought into position 
 with a similar groove in the vertical rolls. 
 
 The Belgian wire rod mill is one in which the stands of rolls 
 are placed in train, i.e., end to end; the modification where 
 the piece was first subjected to a preliminary rolling in an in- 
 dependent stand constitutes the German mill, although this 
 is now generally called a Belgian mill. 
 
 The Bickley mill for hoop and cotton ties consist of three- 
 high rolls through which the piece is passed by repeaters, and 
 provided with devices for taking care of the slack, followed .by 
 a number of two-high finishing stands. 
 
 J. J. Bleckley's four -high mill for wire rods consists of two 
 sets of rolls one above the other in the same housing with a 
 repeater for bending down the piece from the upper to the 
 lower set; a number of such stands could be provided, driven 
 at progressively increasing speeds. 
 
 The Boecker mill is somewhat similar to the Belgian mill, 
 having two lines of stands two-high, one on each side of a driving 
 shaft. 
 
 Brown's reciprocating mill has two pairs of rolls in one set 
 of housings on the same level, the two pairs being run in oppo- 
 site directions. Alternately in each pair the passes are con- 
 siderably larger than in the other, the piece being rolled in 
 the small passes and passing through the large passes without 
 touching them. The object is to run the rolls without revers- 
 ing and to avoid the necessity for a lifting table. 
 
 Brownhill and Smith's mill is three-high with the middle 
 roll slightly larger than the bottom, and the top roll slightly 
 larger than this. 
 
 In Bunsen's mill for rolling hoop there are three pairs of 
 rolls arranged one behind the other, the first and the third 
 set having grooves cut in the bottom roll, and the middle set 
 a groove cut in the top roll. 
 
 The Dowlais mill consists of two pairs of rolls in one set of 
 housings, the bottom roll of one set being on a level with the 
 top roll of the other set, the two pairs being run in opposite 
 directions. The advantage claimed is that there are no dead 
 passes as with an ordinary three-high mill. 
 
 In the Garrett semi-continuous mill, used principally for 
 rolling wire rods, there are a number of stands placed one behind 
 the other, following which are a number of trains of two or 
 three stands each, and driven at successively increasing speeds, 
 the piece being louped around by trough guides in the floor, and 
 arranged so that from two to four pieces can be finished at the 
 same time. 
 
 Gillon and Dujardin's mill is about the same as Lauth's three- 
 high mill. 
 
 The Grey universal mill is designed principally for rolling 
 beams with deeper and thinner flanges than are possible on an 
 ordinary shape mill. The ingots are first rolled into shaped 
 27 
 
4i 8 ROLLING 
 
 blooms (the section roughly started) on- an ordinary cogging 
 or blooming mill, which are then taken to the Grey mill. This 
 consists of two stands, the first of which contains one pair of 
 horizontal rolls only. In these only the edges of the flanges 
 are rolled, i.e., the bloom is rolled down to a thickness corre- 
 sponding to the depth (width) of the flanges required. The 
 second stand has one pair of horizontal rolls and one pair of 
 vertical rolls arranged so they both act on the piece simul- 
 taneously, the horizontal rolls being power driven, while the 
 vertical rolls are friction driven (i.e., from the pressure of the 
 piece against them). The section is guided through the rolls 
 by laterally adjustable guide-bars, and is supported under- 
 neath by guide-rollers. It is never lifted or turned, but passes 
 backward and forward until finished. The horizontal rolls 
 must be changed to conform to the depth of the section, but 
 the vertical rolls which work the outer surfaces of the flanges 
 are wide enough for all sections and therefore need not be changed 
 except when they become badly worn. 
 
 The Josserand and Jacquet process is for rolling bright steel 
 bars. The bars are turned and then rolled to within between 
 o.oi" and 0.05 "of the finished size. Special finishing machines 
 consist of six stands tandem, on a common bed plate but driven 
 independently: (i) straightening, (2) pulling through, (3) 
 roughing cut, (4) pulling through, (5) finishing cut, and (6) 
 planishing (/. /. & S., 1915, i, 591). 
 
 The Kirkstall process for producing rods which are very 
 straight and accurate as to gage consists in taking bars rolled 
 in the ordinary manner to a diameter slightly larger than desired, 
 and then finishing them at a dull red heat between two disks 
 which are parallel to each other and revolve in the same direction, 
 but with their horizontal axes not in the same plane. 
 
 The Kloman process for making eye bars consisted in rolling 
 the billets between reversible and adjustable rolls in such a 
 manner as to leave the ends of the bar thicker than the body. 
 The ends were then spread and forged* and the eye punched 
 out under a steam hammer. 
 
 F. Kogel's universal mill is designed to produce a variety 
 of sections difficult to roll on an ordinary mill by a combina- 
 tion of various processes in some of which the piece is acted 
 upon by rolls without getting any forward movement; it was 
 apparently intended principally for wrought iron. 
 
 The Lackawanna or Mathias deseaming process was devised 
 principally for the purpose of removing the seamy portion of 
 billets entering into the manufacture of rails. "The machine by 
 which the metal is removed subjects the hot rail bar on the top and 
 bottom surfaces to the cutting action from the teeth on two 
 opposed rotating saw disks, just after the hot bar comes down the 
 mill table from the last roughing pass. During this stage of 
 travel a collar turns the rail bar so that its head is down and the 
 base up. The bar then enters a tunnel about 20 feet long and 
 lined with fire-brick to check heat radiation. It is then forced 
 between the saw disks by a pair of driven pinch rolls, adjustable 
 
ROLLING 419 
 
 to bars of various sizes and having guides for the top, bottom and 
 sides of the bar. Adjustment of the saws is made for a cut }^' 
 or at the extreme % " deep. A second set of driven pinch rolls, 
 on the delivery side, helps to force the bar against the cut of the 
 saw teeth and similarly a second set of guides here helps to hold the 
 bars rigidly and firmly during the passage through the saw. 
 From the delivery set of pinch rolls the bar travels through 
 about 40 feet more of tunnel similar to that on the entering side 
 and then to the finishing stand. The hot bar enters the saw at a 
 speed of about 350 feet per minute, is slowed down by the cutting 
 operation to about 79 feet per minute, and on leaving the saw 
 rapidly picks up speed and enters the finishing stand at about 
 500 feet per minute. The upper saw disk (operating on the base) 
 has an 8" and the lower a 6" face. Both are driven from belted 
 motors, are 5 feet in diameter, and run at a peripheral speed of 
 25,000 feet per minute or both disks together make 800,000 tooth 
 contacts with the bar per minute. The rail bars after passing 
 through the machine are further reduced in the rolling operation 
 in 5, more or less, passes to the finished section, so the rail has a 
 rolled surface after the defective material has been removed 
 "(pamphlet, Lackawanna Steel Co., 1914)." 
 
 In S. McCloud's process for rolling old steel rails into flat 
 plates, heavy steel rails are cut into short lengths, heated in 
 the ordinary manner, and then passed endwise through a set 
 of specially prepared rolls which gradually flatten both the head 
 and the flange of the rail without permitting any folding, as 
 the steel would not weld. 
 
 E. W. McKenna's process for rerolling old rails into lighter 
 sections (of rails) is to take the worn rails, heat them in long 
 furnaces, and give them, while at a comparatively low tem- 
 perature, two passes in a tandem mill. The reduction varies 
 with the condition of the worn section, but as a rule gives a 
 rail of about from 10 to 12% lighter weight then the original 
 section (R. W. Hunt). 
 
 The Morgan semi-continuous mill for bars is somewhat 
 similar to the Garrett mill, having a number of stands of rolls 
 one behind the other, and then one train of rolls through which 
 the piece is louped by trough guides in the floor. 
 
 A. Reese's universal mill for beams and channels consists 
 of two sets of rolls; in the first or roughing set the web is rolled 
 by horizontal rolls, and at the same time the width of the flanges 
 is regulated by collars on a pair of vertical rolls; the finishing 
 is done in the second set where the outer sides of the flanges 
 are rolled and the shape finished. It may also be used for 
 plates. 
 
 Rerolling is the term applied to the operation of rolling worn 
 out material into something else; it is used principally for old 
 rails. Rails which are to be rerolled into bars and angles are 
 usually first split longitudinally by putting them through a 
 pass (slitting pass) with collars which slightly overlap and 
 act as a shear, whereby they are divided into three pieces: 
 the head, the web, and the flange. The first is used for rolling 
 
420 ROLLING ROLLING MILLS 
 
 into bars, and the two last for angles and flats. A mill for 
 cutting up nail plate in this manner is called a slitting mill, 
 and no reduction is effected. 
 
 The Sack universal mill, designed principally for rolling 
 cruciform sections, has horizontal and vertical rolls which act 
 upon the piece simultaneously, the general arrangement being 
 much like that of the Wenstrom mill. 
 
 Slick's angular method of rolling (patented by E. E. Slick), 
 which allows shapes with wide flanges to be rolled on ordinary 
 mills other than universal mills having horizontal and vertical 
 rolls, consists in so designing the passes that one flange in the 
 case of a channel, or alternate (diagonally opposite) flanges 
 in the case of a beam, are rolled at an angle considerably greater 
 than 90 to the web, the other flange or flanges going through 
 a dead pass (i.e., not worked), the action being reversed on 
 the subsequent pass. In this way the sides of the flanges receive 
 a considerable amount of work, which is not the case with the 
 ordinary method of rolling. After, the various parts of the 
 section have been reduced to the desired thickness the flanges are 
 bent into their final position in a series of passes'. In all the 
 reducing passes the web is at an angle to the axis of the rolls, 
 this angle being reversed in successive passes. The web is 
 also supported during the passes in which the flanges are bent 
 into their final position. The bending of the flanged shape 
 in passes which support the web is also of importance, as this 
 prevents distortion of the web and insures a good product. In 
 all passes there is no turning of the blank to a position at right 
 angles to that in the previous pass. 
 
 D. Turk's system of rolling wire rods consists of special means 
 of automatically bringing oval or square rods from one pass 
 to another. 
 
 E. D. Wassell's process consists in rerolling old steel rails 
 by the use of rolls of a special form into flat bars about 7,^" 
 wide which are cut, piled, and reheated in a bath of slag, by 
 which means their percentage of carbon can be reduced as 
 desired; the piles are then rolled into the desired shape. 
 
 The Wenstrom mill is a modification of a universal plate 
 mill, designed principally for rolling flats. Instead of acting 
 upon the top and bottom and the two sides at different times, 
 it does this simultaneously. The top roll can be adjusted 
 vertically, and the bottom roll transversely, whereby pieces 
 of different thickness and width can be produced with the 
 same set of rolls. 
 
 Williams' mill consists of two trains of different size rolls 
 designed for producing small bars. 
 
 Certain modifications in details of wire rod mills have been 
 introduced by Martin and Beavis, and F. H. Daniels. 
 
 Rolling Crack. See Crack. 
 
 Rolling Furnace. See page 312. 
 
 Rolling Hardness. See Hardness. 
 
 Rolling Mill. See page 403. 
 
 Rolling Mills, Classification of. See page 409. 
 
ROLLING OFF RUB UP 421 
 
 Rolling Off. (i) In rolling: see page 408; (2) of tubes: see page 
 490. 
 
 Rolling On. Of tubes: see page 490. 
 
 Rolling Open Hearth Furnace. See page 312. 
 
 Ronay Process. See page 44. 
 
 Rontgen Ray Spectrometer. In the study of crystals : see page 1 20. 
 
 Roofing Tin. See page 433. 
 
 Roozeboom's Equilibrium Diagram. See page 272. 
 
 Rope Driven. See page 407. 
 
 Ropiness (Eng.)- A term applied to steel when side ruptures occur 
 in ingots which are being rolled down. 
 
 Rose; Rose Steel. See page 135. 
 
 Rosenhain's Amorphous Cement Theory. See page 282. 
 
 Rosenhain's Equilibrium Diagram. See page 272. 
 
 Rosenhain and Haugh ton's Reagent. For etching: see page 288. 
 
 Rosetti Radiation Pyrometer. See page 207. 
 
 Rossi's Process. This is somewhat similar to Goldschmidt's, 
 employing aluminum for the reduction of metals from their 
 ores or oxides. A bath of molten aluminum is used and on 
 this the ore is thrown. This bath is usually maintained in an 
 electric or other type of furnace so any additional heat required 
 may easily be supplied. 
 
 Rotary Kiln Process. See page 45. 
 
 Rotary Movement. See page 281. 
 
 Rotary (Rotating) Puddling Furnace; Machine. See page 379. 
 
 Rotary Shears. See Shears. 
 
 Rotary Squeezer. See page 377. 
 
 Rotation Effect. Of oblique light: see page 127. 
 
 Rotator. See page 379. 
 
 Rotten ; Rottenness. A piece of metal is said to be rotten when, on 
 account of burning, high sulphur, or imperfect deoxidation in 
 manufacture, it crumbles or falls to pieces, or cracks when rolled 
 or forged; a term rarely applied to brittleness. 
 
 Rough Fracture. See page 178. 
 
 Rough Roller. See page 414. 
 
 Roughened Tin Plate. See page 433. 
 
 Roughing. (i) In general, preliminary, as roughing rolls, roughing 
 passes (of ingots, etc.), roughing out (machining), etc.; (2) rag- 
 ging (Eng.) : see page 407. 
 
 Roughing Block. In wire drawing: see page 508. 
 
 Roughing Cinder. See Slag. 
 
 Roughing Hole (South Staffordshire). In old blast furnaces pro- 
 vided with a tymp, etc., a hole in the runner at the bottom of the 
 cinder fall, where the cinder was collected around an iron rod and 
 so removed. 
 
 Roughing Loam. See page 301. 
 
 Roughing Roll; Roller; Stand. See page 403. 
 
 Roughing Cinder; Slag. See Slag. 
 
 Round. In charging a blast furnace:, see page 33. 
 
 Round Top Furnace. See page 313. 
 
 Rowling (obs.). Rolling. 
 
 Rub Up (Eng.). To stir up or rabble a metallic bath. 
 
422 RUBBLE RUTHENBURG PROCESS 
 
 Rubble. (i) Rabble; (2) a mixture of gravel and cement. 
 
 Rubble Ironstone. See page 244. 
 
 Rudolphs -Landin Process. See page 145. 
 
 Ruelle Test. See page 482. 
 
 Ruff's Equilibrium Diagram. See page 272. 
 
 Rumble; Rumbling Mul. See page 58. 
 
 Run (verb). (i) Of a crucible: see page 113; (2) of a cupola: see 
 
 page 182. 
 
 Run Down; Running Down. Of a cupola: see page 182. 
 Run a Melt. Melting iron in a cupola for foundry work. 
 Run-of-Mine Coal. See Coal. 
 Run-out Fire. See page 383. 
 Run Steel. See page 257. 
 Runner. (i) Of a blast furnace: see page 36; (2) of a casting: 
 
 see pages 57 and 299. 
 Runner Head. See page 57. 
 Running Mold. See page 57. 
 Running-out Fire. See page 383. 
 Running Stopper. See Ladle. 
 
 Runnings (obs.). Molten metal from a blast furnace. 
 Rupture. See pages 177 and 330. 
 Rupture by Bursting. See page 179. 
 Russell Test. See page 482. 
 Russia Iron; Russian Sheet Iron. See page 431. 
 Rust. See pages 106 and 367. 
 Rust Coating. For wire: see page 507. 
 Rust Proof Coating. See page 367. 
 Rust Proof Processes. See page 367. 
 Ruthenburg Process. See page 163. 
 
S. Chemical symbol for sulphur, q.v. 
 
 Sa. Chemical symbol for samarium: see page 84. 
 
 Sb. Chemical symbol for antimony (Latin, stibium}, q.v. 
 
 Sc. Chemical symbol for scandium: see page 84. 
 
 Se.. Chemical symbol for selenium: see page 84. 
 
 Si. Chemical symbol for silicon, q.v. 
 
 Sn. Chemical symbol for tin (Latin, stannum), q.v. 
 
 ST. Chemical symbol for strontium: see page 84. 
 
 S.A.E. Society of Automotive (formerly Automobile) Engineers. 
 
 S.C.I. Swedish charcoal (wrought) iron. 
 
 S.W.G. (i) Steel wire gage; (2) British standard or imperial 
 wire gage; (3) Stubs' wire gage. 
 
 Sack Mill. See page 420. 
 
 Sackur's Theory. Of passivity: see page 364. 
 
 Sadden or Saddening Heat. See page 116. 
 
 Safe Load ; Range of Stress. See page 468. 
 
 Safety, Factor of. See page 468. 
 
 Sag; Sagg. To (cause to) sink down or become compacted. 
 
 Saggar; Sagger. (i) In -making crucibles: see page 112; (2) for 
 malleable castings: see page 258; (3) in molding: see page 300. 
 
 St. Chamond Armor Plate. See page 9. 
 
 St. Etienne Process. See page 64. 
 
 Sainte-Claire-Deville Gas Pyrometer. See page 207. 
 
 Saklatwalla's Iron -Phosphorus Diagram. See page 272. 
 
 Sal ammoniac. Commercial ammonium chloride. 
 
 Salamander. (i) The old name for the bloom from a direct 
 furnace (see page 135); (2) the iron forming the scaffold in a 
 cupola (rare); (3) a stove, usually cylindrical in shape, made of 
 plates and filled with coke or coal, for warming portions of a mill 
 building, particularly to prevent the freezing up of valves and 
 pipes; (4) the infusible mass found in the hearth of a blast 
 furnace when it is torn out for relining; also called bear, sow, or 
 horse. This may consist of (a)' iron containing, considerably 
 lower carbon than the regular pig iron, and (b) a copper-colored 
 substance composed principally of cyano-nitride (nitro-cyanide) 
 of titanium, to which the formula (Ti 6 CN) 4 has been given. 
 Contained in, or associated with, this bear or salamander is what 
 has been erroneously termed amianthus (the name of a variety 
 of asbestos), or furnace amianthus: "It is white, and of a finely 
 fibrous structure (fibrous silica), and here and there it is distinct- 
 ly seen to consist of more or less globular aggregations of radiating 
 fibers. It is associated with minute brilliant crystals of cyano- 
 nitride of titanium, and, freed from these it was found by analysis 
 to contain 97.5% SiOa with traces of lime and manganese" 
 (Percy) 
 
 423 
 
424 SALAMANDER FURNACE SAW FILE TEMPER 
 
 Salamander Furnace. See page 147. 
 
 Salom's Formula. For tensile strength: see page 339. 
 
 Salt. (i) Ordinary salt, sodium chloride, NaCl; (2) the combina- 
 tion of an acid with a base: see page 88. 
 
 Salzburg Process. See page 78. 
 
 Sample Spoon. See Spoon. 
 
 Sampling Pig Iron. See page 349. 
 
 Sand. (i) Of ingots: see page 56; (2) as a flux: see page 176; 
 (3) as a refractory: see page 395. 
 
 Sand Blower. See page 492. 
 
 Sand Boil. See page 314. 
 
 Sand Bottom. See Lining. 
 
 Sand Cast Pig. See page 342. 
 
 Sand Core Process. See page 65. 
 
 Sand Mold. See page 296. 
 
 Sandberg Process. See page 233. 
 
 Sandstone. See page 395. 
 
 Saniter Desulphurizing Process. See page 387. 
 
 Saniter's Reagent. For hot etching: see page 287. 
 
 Saniter Steel. Steel made by the Saniter desulphurizing process: 
 see page 387. 
 
 Saniter Wear Test. See page 480. 
 
 Sankey Test See page 482. 
 
 Sap. In cementation: see page 71. 
 
 Sappy Fracture. See page 178. 
 
 Sarnstrom Process. See page 145. 
 
 Satisfied. Combined, so that the substance has no further chemical 
 affinity under the existing conditions, as lime combined with the 
 requisite amount of silica; this term must be distinguished from 
 saturated. 
 
 Sattman and Hornatsch Process. See page 145. 
 
 Saturated Austenoid. See page 275. 
 
 Saturated Compound. See page 85. 
 
 Saturated Martensite. See page 276. 
 
 Saturated Solution. See Solution. 
 
 Saturated Steel. See page 273. 
 
 Saturated Vapor. See page 202. 
 
 Saturator. Of by-product gas: see page 96. 
 
 Saucer Bosh. See page 27. 
 
 Saunderson Process. See page 64. 
 
 Sauveur's Critical Strain. See page 216. 
 
 Sauveur's Equilibrium Diagram. See page 272. 
 
 Sauveur's Formulae. For tensile strength and elongation: see 
 page 339. 
 
 Sauveur's Hypothesis. On the allotropic transformation of iron: 
 see page 278. 
 
 Sauveur Process. (i) For sound ingots: see page 60; (2) of 
 coarsening ferrite: see page 216. 
 
 Sauveur's Reagent. For etching: see page 287. 
 
 Sauveur and Whiting's Thermomagnetic Selector. See page 210. 
 
 Saw File Temper. See Temper. 
 
SCAB SCORIA PROCESS 425 
 
 Scab, Scabby. (i) On castings: see page 58; (2) a defect in 
 
 plates, etc.: see page 357. 
 Scaffold. See page 35. 
 
 Scaffolding Down. Of a blast furnace: see page 37. 
 Scale. (i) The coating of oxide which forms on the surface of 
 
 metal which is heated. This scale is cracked and broken off 
 
 during working, and according to the method is termed roll scale 
 
 (mill scale) or hammer scale; (2) usually scales: an instrument 
 
 for weighing, usually heavy bodies. 
 Scale Pit. See page 407. 
 Scaled Casting. See page 258. 
 Scaling. (i) Of drawings or blue prints, measuring dimensions 
 
 with a scale instead of depending on dimensions as marked: an 
 
 inaccurate method; (2) a defect: see Pit. 
 Scalping. Of crucibles: see page 112. 
 Scar. In a blast furnace: see page 38. 
 Scarf. (i) To bevel (also the bevel) the edges of skelp in the process 
 
 of making lap- welded pipe: see page 489; (2) to hollow the side 
 
 of a shaft, etc., in forging. 
 Scarf Weld; Joint. See page 502. 
 Scarfing Test. See page 476. 
 
 Scattering. Of liquid steel in a mold, etc., spitting. 
 Scelp (Eng.). Skelp. 
 
 Schaffer and Budenberg's Thalpotassimeter. See page 210. 
 Schamotte. See page 396. 
 Schiebler Process. See page 22. 
 Schillerization. See page 127. 
 Schiseophone. See page 483. 
 Schmidhammer Process. See page 145. 
 Schneider et Compagnie Process. See page 230. 
 Schneider-Creusot Furnace. See page 163. 
 Schneider Furnace. See page 163. 
 Schb'nawa-Rodenhauser Furnace. See page 162. 
 Schoop Process. See page 373. 
 Schreibersite. See page 292. 
 Schulte-Hemmis Process. For producing hollow bodies or shells 
 
 from malleable metals, chiefly by pressure. 
 Schumacher Process. See page 44. 
 Schungite. See Carbon. 
 Schwartz Process. See page 319. 
 Sclerometer. See page 480. 
 Scleroscope. See page 478. 
 
 Scobel- Johnson Apparent Elastic Limit. See page 470. 
 Scobel's Yield Point. See page 470. 
 Scone (Scotch). A fireclay disk or biscuit used in patching the 
 
 lining of furnaces, etc. 
 Scorched Fracture. See page 178. 
 Scorched Ingot (Eng.). See page 57. 
 Scoria; Scoriae (plur.). See Slag. 
 Scoria Block; Plate. See page 32. 
 Scoria Process. See page 44. 
 
426 SCORIACEOUS SEAM 
 
 Scoriaceous. Like or resembling cinder. A term applied to a 
 structure presenting the appearance of slag. A term which has 
 been used when the exact nature of .the substance is not known 
 when detected as inclusions in metals and alloys (I.A.T.M.). 
 
 Scoride (rare). Cinder. 
 
 Scorodite. See page 244. 
 
 Scotch Iron. See page 350. 
 
 Scotch Tuyere. See page 31. 
 
 Scott process. See page 61. 
 
 Scouring; Scouring Barrel. See page 507. 
 
 Scouring Cinder. See Slag. 
 
 Scrag (Eng.). To straighten a spring, etc., which has been cam- 
 bered (bent), by pushing in the bulge and releasing. 
 
 Scrap; Scrapping. (i) In the Bessemer process, throwing steel 
 scrap into the vessel when the metal is blowing too hot; (2) of 
 molds, removing the steel which has run over the top and down 
 the sides during pouring; (3) in general parlance, discarding 
 anything, such as machinery, which is. out of date or wornout; 
 also the material which is discarded. See Discard. 
 
 Scrap Ball; Bar; Furnace; Iron. See page 379. 
 
 Scrap and Pig Process ; Scrap* Process. Usually called pig and 
 scrap process: see page 310. 
 
 Scraper. See page 415. 
 
 Scratch Hardness. See page 331. 
 
 Screen. A large sieve used for separating fine from coarse material. 
 It consists of woven wire, or of a steel plate, having holes whose 
 size depends upon the fineness of the product required. A 
 revolving screen is a revolving cylinder made of steel plates, 
 generally inclined slightly downward so that material will move 
 forward by gravity, and usually having holes of a different size 
 in different parts, the smaller being at the upper end. 
 
 Screw Down. See page 414. 
 
 Scribe Method; Scriber Method (Eng.). For yield point: see 
 page 470. 
 
 Scroll Bundle. See Coil. 
 
 Scrubber. For gas: see page 33. 
 
 Scruff; Scruffy. The dirt or impurities on the surface of an object 
 causing roughness; also the condition. 
 
 Scull. See Skull. 
 
 Scum. See page 115. 
 
 Scurf. To flake off, or the material which flakes off; dross. 
 
 Sea Coal. See Coal. 
 
 Seam. (i) In tubes: see page 489; (2) in welding: see page 502. 
 
 Seam. Also called roak or roke (Eng.); a crack on the surface of 
 
 very tme it may 
 hair crack or hair seam. A lap seam, lap, cold lap, or cold shut 
 is produced when a fin or ridge is formed and doubled over in 
 forging or rolling. A snake or streak is a long wavy seam. 
 Longitudinal and transverse seams are those extending length- 
 wise or crosswise respectively of the piece as produced. A 
 
SEAMLESS TUBE SEMI-CONTINUOUS MILL 427 
 
 spiral seam occurs in the manufacture of seamless tubing when a 
 surface defect is extended spirally in the process of piercing. 
 
 Seamless Tube. See page 490. 
 
 Season. Of crucibles: see page 112. 
 
 Season Crack. See Cold Working. 
 
 Seaton and Jude Test. See page 482. 
 
 Seaton Test. See page 482. 
 
 Sebenius Process. See page 62. 
 
 Seconds. Of sheets: see page 433. 
 
 Second Annealing. Of sheets: see page 431. 
 
 Second Class Foam Cells. See page 121. 
 
 Second Order Cells. See page 121. 
 
 Second Pickling. Of sheets: see page 431. 
 
 Second Strand. See page 415. 
 
 Secondary Crystals. See page 121. 
 
 Secondary Crystallization. See page 121. 
 
 Secondary Furnace. See page 316. 
 
 Secondary Gas. See page 33. 
 
 Secondary Hardening. See page 447. 
 
 Secondary Metals. The term secondary is applied to metals 
 recovered from scrap metal, sweepings, skimmings, drosses, etc., 
 as distinguished from primary metals which are obtained direct 
 from ore. The term "secondary" carries no implication of 
 inferiority in quality (terms as used by the U. S. Geol. Survey). 
 
 Secondary Slip. See page 283. 
 
 Secondary Stress. See page 332. 
 
 Secondary Twinning. See page 123. 
 
 Sectile. See page 124. 
 
 Section; Section Area. See page 468. 
 
 Section of Failure. See page 337. 
 
 Section Mill. See page 409. 
 
 Seger Cones. See page 209. 
 
 Seggar. See pages 112 and 300. 
 
 Segregans. Mother metal: see page 56. 
 
 Segregate. See page 56. 
 
 Segregated Cementite. See page 273. 
 
 Segregated Spot. See Hard Spot. 
 
 Segregation. See pages 55 and 442. 
 
 Segregation Deficit; Excess. See page 56. 
 
 Seguin Process. See page 229. 
 
 Selective Corrosion. See page 106. 
 
 Selective Effect. Of oblique light: see page 127. 
 
 Selective Freezing. See page 266. 
 
 Selective Transformation. See pages 271 and 275. 
 
 Selenium, Action of Light on. See page 208. 
 
 Self -corrosion. See page 108. 
 
 Self -fluxing Ore. See page 243. 
 
 Self -hardening Steels. See pages 446 and 451. 
 
 Self -roasting Ore. See page 243. 
 
 Self -strained; Self -stressed. See page 332. 
 
 Semicombined. See page 83. 
 
 Semi-continuous Mill. See page 416. 
 
428 SEMI-CRYSTALLINE STRUCTURE SHEARS 
 
 Semi-crystalline Structure. See page 125. 
 
 Semi-direct Process; Recovery Process. In by-product coke 
 ovens: see page 96. 
 
 Semi-finished. See Finished. 
 
 Semi-finished Products; Mills for. See page 411. 
 
 Semimetal (obs.). Metalloid; possessed of some but not all the 
 (physical) properties of a metal. 
 
 Semi-products. See page 411. 
 
 Semi-steel. Also called toughened cast iron or Sterling's tough- 
 ened cast iron; it is produced by melting about one-third to 
 one-fifth by weight of wrought iron or soft steel scrap with 
 cast iron, usually in a cupola, and is employed in the manufacture 
 of castings, known as semi-steel castings. 
 
 Semi-steel Casting. See Semi-steel. 
 
 Semi-water Gas. See Producer. 
 
 Semi-wild. Same as lively, q.v. 
 
 Sensible Heat. See page 199. 
 
 Sentinel; Sentinel Pyrometer. See page 209. 
 
 Set. (i) Of steel ingots, etc., after pouring, when a skin or crust of 
 sufficient thickness has formed, so that when the molds are 
 removed the metal will not run out; (2) distortion: see page 334. 
 (3) in coating sheets: see page 432. 
 
 Set Temper. See Temper. 
 
 Setter In. In the crucible process: see page 114. 
 
 Setting Down. In forging: see page 177. 
 
 Settling Head. See page 56. 
 
 Settling Tank. In the purification of water, a tank in which muddy 
 water or water which has been chemically treated, is allowed to 
 stand until the impurities have collected on the bottom. 
 
 Seventy-two Hour Coke. See page 95. 
 
 Shackles. Of a testing machine: see page 469. 
 
 Shadow Line. See page 289. 
 
 Shaft. (i) The interior of a shaft furnace above the boshes; (2) a 
 circular bar or rod of steel used for conveying power by rotation. 
 
 Shaft Furnace. Seepages 114 and 181. 
 
 Shaft Washer. See Ore. 
 
 Shake Down. See page 314. 
 
 Shaking Barrel. See page 58. 
 
 Shank; Shank Ladle. See Ladle. 
 
 Shape Mill. See page 409. 
 
 Shape Work. See Hammer. 
 
 Shaped Bloom. See page 417. 
 
 Shaping Process (Howe). For giving to material a desired form or 
 shape as by rolling or forging (working) or by melting and 
 casting in molds. 
 
 Sharp. (i) Of a casting: see page 58; (2) of a flame; oxidizing. 
 
 Sharps. See page 432. 
 
 Shaw Process. (i) For casting: see page 65; (2) for purifying: 
 see page 387. 
 
 Shears. A machine for cutting up or dividing pieces of metal 
 consisting of two knife blades, one of which is fixed and the other 
 movable and operated up and down (rarely sideways) by steam 
 
SHEAR BLADE TEMPER SHEETS 429 
 
 or electrically driven gears or by hydraulic power. The usual 
 gear-driven shears has the upper movable knife set at a slight 
 angle (rake) to the lower and is termed a guillotine shears; 
 its advantage is that only a small part of the edge is cutting at one 
 time and hence less power is required than if the edges are 
 parallel. A rotary shears, for producing round plates, has a 
 horizontal revolving table to which the plate is fastened, and set 
 at the proper distance are two vertical disks, one above the other 
 and arranged so their edges slightly overlap; they revolve in 
 opposite directions and cut off the edge of the plate between 
 them. A type frequently used for cutting up scrap, muck bar, 
 etc., called alligator shears, crocodile shears, lever shears, or 
 cropping shears, has two jaws, one of which is fixed while the 
 other is pivoted and actuated by a cam arrangement. 
 
 Shear Blade Temper. See Temper. 
 
 Shear Steel. Also called sheared steel or German steel (obs.). 
 It is the product obtained by welding and forging plated bars 
 (see page 71), and is made principally in England. These 
 bars are broken into suitable lengths, six piled together, con-, 
 stituting a fagot, covered with fireclay and borax to prevent 
 excessive oxidation, and drawn out under a hammer into a 
 bar (single shear steel). If this bar is doubled and rehammered 
 it is known as double shear steel. The product is used for 
 articles of cutlery, etc. 
 
 Sheared Plate Mill. See page 413. 
 
 Shearing. In general, cutting: see also page 101. 
 
 Sheared Steel. See Shear Steel. 
 
 Shearing Modulus of Elasticity. See page 335. 
 
 Shearing Resilience. See page 33.1. 
 
 Shearing Strength. See page 330. 
 
 Shearing Stress. See page 332. 
 
 Shearing Test. See page 477. 
 
 Sheathing. A protective outside coating or jacket of metal or 
 wood. 
 
 Sheet. See below. 
 
 Sheet Bar. See page 411. 
 
 Sheet Furnace. See page 430. 
 
 Sheet Gage. See page 188. 
 
 Sheets, Manufacture of. See page 430. 
 
 Sheet Metal Gage. See page 188. 
 
 Sheet Mill. See page 430. 
 
 Sheets and Tin Plate. The dividing line between sheets and 
 plates is not sharply drawn, but depends principally upon the 
 type of mill on which they are rolled; it may roughly be taken 
 that plates are %" thick and over, and sheets thinner than this. 
 U. S. Government has set the limit for sheets at No. 10 U. S. 
 Standard Gage. Tin plates (tinned plates). are sheets (usually 
 of light gage) coated with tin to protect them from corrosion; if of 
 heavy gage, they are sometimes called tinned sheets. The 
 material used in the manufacture comes in the form called generi- 
 cally sheet bars; those for tin plates are also called specifically 
 tin bars or tin plate bars. The mills on which these bars are 
 
430 SHEETS AND TIN PLATE 
 
 rolled into sheets are of the two-high, non-reversing type known 
 as pull over (see page 408), and are classed as sheet mills and tin 
 mills. As a rule sheet mills do not roll much below No. 28 gage, 
 although they can go down to about No. 30; tin mills commonly 
 do not go above No. 20 although they can go up to No. 16. In 
 this country sheets are started in one stand of rolls and finished 
 in another (double mill) ; tin plates are rolled in one stand 
 (single mill). 
 
 Manufacture of Sheets. With extra heavy sheets only 
 one is rolled at a time, and is called a single (single steel). 
 Ordinarily two bars are rolled simultaneously and are called a 
 pair (the sheets are then doubles or double steel), and the small 
 reverberatory furnace in which they are heated, a pair furnace. 
 In rolling pairs the bars are put successively through the rolls 
 by the roller and are seized on the other side by another man 
 (the catcher) who places each on top of the top roll, to be taken 
 off by the roller as the other is going between the rolls. After 
 receiving a certain amount of reduction they are taken to the 
 finishing stand where they are rolled separately still further, 
 and then one is laid on top of the other and rolling is continued 
 until they are too cold. The rolls become heated, particularly 
 in the middle, which causes a certain amount of expansion; 
 this is partially offset by turning them slightly concave in a 
 lathe; if the expansion is extreme, the rolls are said to be puffed. 
 After the last rolling the two sheets are separated and a number, 
 depending upon the desired gage, piled together in a pack, the 
 longer ones on the bottom, this operation being known as match- 
 ing, and the man who attends to it the matcher. They are now 
 bent double transversely and the bend stamped flat by a machine 
 called a doubler, a form of hammer having a long flat face. If 
 the doubler forms part of a shear (in the case of light sheets) 
 of the crocodile type, it is termed a doubling shear. The packs 
 are reheated in the sheet furnace (a rash is occasioned when the 
 outside is heated much hotter than the interior) and rolled down 
 to the desired gage, after which the packs are sheared and opened, 
 i.e., the sheets are pulled apart. Sheets difficult to separate are 
 called stickers. The operation is usually performed by pulling 
 the sheets off by hand, or, in the case of stickers, with a pair of 
 tongs, the rest of the pack being held down with the foot. In 
 some cases the strip sheared from the edge of a pack, held in one 
 hand like a sword, is brought down between two stickers, which 
 is called swording stickers. To prevent sheets from sticking 
 during hot rolling, it was at one time the practice, in certain 
 localities, to sift coal slack, sawdust, etc., between them, called 
 dusting; this practice has been almost entirely abandoned. 
 Horns are projections at the end of a sheet caused by the sides 
 rolling out longer than the middle. Jumping is where a sheet 
 slips when the pack is rolled, causing buckling or lapping by the 
 rolls. Such a sheet bent or doubled over is called a lapper, 
 pinched sheet, or simply a pincher. Almost no sheets are sold as 
 they come from from the hot rolls; in this condition they are 
 known as red hard sheets. Practically all the product is an- 
 
- SHEETS AND TIN PLATE 431 
 
 nealed to be sold as black plate (finished black plate) or is coated 
 with zinc for galvanized sheets. For annealing they are piled on 
 a bottom, and covered with a steel or iron box (annealing box, 
 annealing pot) to exclude the air, the operation being known as 
 close annealing or box annealing. They are then heated in a 
 furnace to about 760 to 870 C. (1400 to 1600 F.), which re- 
 quires, altogether, about 1 6 to 20 hours. The top sheets from var- 
 ious piles are known as outsides, and are oxidized more than the 
 others. By another method, known as blue annealing, the 
 sheets, if fairly heavy, are allowed to cool slowly after the hot 
 rolling, or if of lighter gage, as is usually the case, they are passed 
 singly through an open furnace where they are reheated to the 
 proper temperature for the annealing or softening operation. As 
 the name indicates, they have a bluish-black appearance. Aside 
 from the color of the sheets, the properties resulting from the two 
 methods are practically the same. This method is also known as 
 open annealing, the sheets being exposed directly to the air. For 
 galvanizing they are now pickled for 5 to 10 minutes in dilute sul- 
 phuric acid to remove the scale, being held loosely in racks or 
 cradles so the acid may penetrate between. They are next washed 
 with water (swilled) in tanks to remove the acid, and are kept sub- 
 merged in water until just before they are galvanized, when they 
 are put for a few minutes in a very weak solution of acid. Galvan- 
 izing is effected by passing the sheets through the galvanizing pot 
 or kettle, a deep iron vessel filled with molten spelter (commercial 
 zinc), this method, which is always used for sheets, being termed 
 pot galvanizing. The markings or spangles on the surface of 
 galvanized sheets is due to the crystallization of the zinc, the size 
 depending upon the rate of cooling. Russian sheet iron or 
 Russia iron is a special grade of sheet with a glossy black, slightly 
 mottled appearance due to oxide adhering to the surface so 
 tenaciously that it cannot be cracked off by repeated bendings. 
 It is produced by hammering a pile of heated sheets having very 
 slight projections or indentations on the surface, with or without 
 charcoal powder sifted between before heating. Sheets ham- 
 mered in this way to get a polished surface are said to be planished 
 (rarely called glanced sheets). 
 
 Manufacture of Tin Plates. The process up to the anneal- 
 ing operation is practically the same as that for the manufacture 
 of sheets. Here, however, there is a slight change. The plates 
 are first pickled (black pickling or first pickling) as already 
 described. After swilling they are annealed in boxes (black 
 annealing or first annealing), and are then cold rolled, i.e., given 
 a number of passes (usually three) cold through rolls (cold rolls) 
 to make the surface perfectly smooth so the finished tin plate 
 will have a high polish. As this renders them somewhat stiff 
 they are reannealed (white annealing or second annealing) 
 at a slightly lower temperature than before. Plates may be 
 sold simply cold rolled or cold rolled and annealed. If to be 
 tinned they are again pickled (white pickling or second pickling) 
 and swilled. They are then passed through a pot filled with 
 molten tin (white pot, tin pot, tinning pot) . According to modern 
 
43 2 SHEETS AND TIN PLATE - 
 
 methods the coating of sheets is performed in one operation by 
 passing them through the pot of molten metal between driven 
 rollers arranged in pairs, the last pair squeezing off the surplus 
 metal. In England these mechanical tinning pots are sometimes 
 called patents. The necessary equipment for coating tin or 
 terne plates is called a set : For terne and coke plates it consists 
 of a pot containing tin or the terne mixture covered with palm 
 oil, and rolls; for charcoal plates there are a palm oil tin pot, a 
 wash pot, and a roll pot (each separate). A combination pot 
 means a white pot with rolls and then a tin pot with rolls. The 
 early method of tinning, called dipping, was done by hand and 
 was more complicated. The cleaned sheets were first put in a 
 pot of grease (tinman's pot) the temperature of which was very 
 low. A number of plates were next plunged into the tin pot 
 containing molten tin covered with grease. From this they were 
 passed to the larger of two compartments in the wash pot filled 
 with molten tin of better quality than in the tin pot, in which 
 they could remain some time without becoming dry (i.e., becom- 
 ing so hot very little tin would adhere); they were then taken out 
 singly and rubbed on each side with a hemp brush, after which 
 they were redipped in the smaller compartment of the wash 
 pot, containing the best quality of tin, to obliterate marks 
 made by the brush. They were next transferred to the grease 
 pot (grease pan) filled with palm oil, or palm oil and tallow, 
 at a fairly high temperature, where the surplus tin drained off, 
 amounting sometimes to two or three times what remained 
 on the plate. They next went to the cold pot, where they were 
 allowed to cool exposed to the air. The excess of tin draining 
 off the plate left an accumulation (wire or list) at the bottom 
 edge which was removed by dipping in the list pot, a pot con- 
 taining a layer of molten tin about %" deep, and considerably 
 above its melting-point. When the wire was perfectly fused 
 it was removed by lifting the plate and giving it a quick blow 
 with a stick. The plates were then worked in troughs with 
 bran, and polished. 
 
 The surface of the molten tin in the tin pot is covered with a 
 layer of palm oil to prevent oxidation and, as some of this adheres 
 to the plates, it is necessary to clean them. This was formerly 
 done by hand but now usually by a machine (branning machine) 
 through which the plates are passed, a series of revolving brushes 
 applying bran or a mixture of sawdust and lime to the surface. 
 Sharps (the hard part of wheat) or middlings and shudes (the 
 hulls of grain) are sometimes used for this purpose. 
 
 A patch, or black patch, on tin plates is a stain caused by 
 scale which has not been properly cleaned off. Black edged 
 or smoky edged plates are of infrequent occurrence and are 
 due to too low a temperature in annealing; they coat with tin 
 but show a dark stain along the edge. White edged plates, 
 which also are of infrequent occurrence, are those which have 
 been overheated in the white annealing; they do not coat well 
 either with tin or lead. 
 
 Terne plates are made in the same way as tin plates, except 
 
SHEETS 'AND TIN PLATE 433 
 
 that the coating consists of a mixture of tin and lead, running 
 from about 50 to 75% tin, ordinarily about 70%. The surface 
 has a dull appearance and is covered with markings (mottles) 
 caused by crystallization of the mixture, the size depending 
 principally on the rate of cooling. According to whether the 
 plates are passed through dry bran or bran moistened with 
 oil, they have a dry finish or an oil finish respectively. 
 
 Tin and terne plates, after being finished, receive a final 
 inspection in the assorting room, all first quality sheets being 
 known as primes, if of inferior quality as seconds, while all badly 
 defective material (wasters) is thrown out. They are then 
 packed in boxes. The unit of measure, irrespective of the gage 
 (which is always shown), is known as the base box. This is 
 figured as the number of square inches on one side of each plate, 
 and amounts to 31,360 square inches; in England it corresponds 
 to 1 1 2 plates, 14" X 20", No. 30 gage, weighing 112 pounds. Ordi- 
 nary plates are sheared to size immediately after the hot rolling, 
 but those of small size may be cut up from a large plate after 
 finishing. When required to be very accurate as to size, they 
 may be trimmed after finishing, when they are known as re- 
 squared plates. 
 
 Sheets (usually galvanized for roofing) are corrugated by 
 passing between a pair of rolls in the surface of which corruga- 
 tions (grooves) have been cut longitudinally. In England 
 sheets or plates of 20 gage or thicker are called singles; 21 to 24 
 gage, doubles; 25 to 27 gage, trebles or lattens; and those down 
 to 29 gage, extra lattens; taggers are very thin plates largely 
 used for metal tags. Coke plates or sheets (coke tins or cokes) 
 were formerly those made from iron puddled from coke pig, and 
 charcoal plates or sheets were those made from charcoal hearth 
 wrought iron or from iron puddled from charcoal pig; at present 
 this significance has been lost as both are practically always made 
 from soft steel (either Bessemer or open hearth), the charcoal 
 plates carrying a heavier coating of tin, and therefore of higher 
 quality ( and price). The amount of coating is usually shown by 
 letters, the numbers increasing with the thickness of coating, as 
 A, and AAAAA. For tobacco cans and similar purposes the 
 sheets are sometimes not cold rolled as the rougher surface takes 
 more tin for coating and has a dull silvery finish; these are called 
 roughened tin plates. All terne plates are commonly called 
 roofing tin. Tinned or galvanized sheets were at one time called 
 white iron and an artificer in them a whitesmith. 
 
 The Bray continuous sheet mill consists of six sets of two- 
 high rolls tandem, the bars being fed separately, and two arms 
 engaging the rear of each bar and moving it forward squarely 
 into each set of rolls. After passing through these rolls a suffi- 
 cient number of sheets are collected in a matcher, and the 
 resultant pack is passed by feed rollers into the first of three 
 sets of two-high rolls, also set tandem, between which it is 
 carried forward by chain tables. After leaving the last set 
 the pack is passed through a vv^ter bosh and thence through 
 an opening machine in which the plates are loosened. The 
 28 
 
434 SHELDON PROCESS SIBUT PROCESS 
 
 pack is then doubled in a roller doubler, reheated, and finished 
 as usual. 
 
 The Donner continuous sheet mill consists of four sets of 
 two-high rolls set tandem, with feed tables or conveyors between 
 each set. At a sufficient distance from the last of these to allow 
 matching of the sheets which individually had received the four 
 customary passes, two additional sets of two-high rolls are placed 
 tandem, and after passing through these the pack is doubled, 
 reheated, and finished much as usual. 
 
 Howell's mill, designed for rolling sheets, consists of a bloom- 
 ing train followed by a number (usually four) of stands of rolls 
 on the continuous principle. 
 
 The Wittgenstein mill, for thin plates or sheets, consists 
 of a Lauth three-high mill for roughing, followed by five stands 
 of two-high rolls, one behind the other, and so close together 
 that the plate may be in all five stands simultaneously. 
 
 Sheldon Process. See page 384. 
 
 Shell. (i) A defect: see Pit; (2) a casing; (3) in cold rolling or 
 drawing: see page 101; in crystallography: see page 126. 
 
 Shelling. (i) A defect: see Pit; (2) in cold rolling or drawing: see 
 page 10 1. 
 
 Shelling Out; Shelly. See Pit. 
 
 Sherard Process; Sherardizing. See page 371. 
 
 Sherk and Rutter Converter. See page 24. 
 
 Sherman Process. See pages 380 and 387. 
 
 Shingling. See pages 177 and 377. 
 
 Shock. See pages 330 and 333. 
 
 Shock Test. See page 481. 
 
 Shop Coat. See page 365. 
 
 Shore Layers. In the freezing of alloys : see page 54. 
 
 Shore Pyroscope. See page 208. 
 
 Shore Scleroscope; Test. See page 478. 
 
 Short; Shortness. See Brittleness. 
 
 Short Heat. See page 226. 
 
 Short-tailed Monkey. See Monkey. 
 
 Short Ton. See Ton. 
 
 Shortening. In compression: see page 336. 
 
 Shot Iron. Irregular globules of cast iron, usually about ^ to %" in 
 diameter, produced when soine of the contents of a ladle splash on 
 a damp floor, or produced when a cupola is dumped. 
 
 Shoulder. (i) Of a converter: see page 18; (2) of a roll: see page 
 
 43- 
 
 Shrink Hole. See page 53. 
 Shrinkage Gage. See page 296. 
 Shrinkage Test. See page 484. 
 Shrinking. See Cold Working. 
 Shrinking Head. See page 56. 
 Shudes. See page 432. 
 Shut. See page 502. 
 Shutter. See page 36. 
 Sibbering. See page 376. 
 Sibut Process. See page 64. 
 
SIDE BLOWN CONVERTER SILICO-MANGANESE 435 
 
 Side Blown Converter. See page 18. 
 
 Side Fed Tuyeres. See page 31. 
 
 Side Shears. See page 413. 
 
 Siderite. (i) Kind of iron ore: see page 244; (2) kind of meteorite: 
 
 see page 290. 
 
 Siderography. Engraving on iron or steel. 
 Siderolite. See page 290. 
 
 Siderology ( Juptner) ; Siderurgy. Metallurgy of iron. 
 Siegen Process; Raw Steel Finery Process. See page 78. 
 Siemens Calorimeter. See page 201. 
 Siemens Calorimetric Pyrometer. See page 207. 
 Siemens Electric Furnace. See page 163. 
 Siemens Electric Resistance Pyrometer. See page 208. 
 Siemens Furnace. See pages 183 and 310. 
 Siemens Gas. See Producer. 
 
 Siemens and Halske Recording Pyrometer. See page 210. 
 Siemens-Martin Process. See page 310. 
 Siemens Precipitation Process. See page 146. 
 Siemens (C. W.) Process. (i) Of casting: see page 64; (2) direct: 
 
 see page 146; (3) open hearth: see page 310; (4) purification: 
 
 see page 387. 
 
 Siemens (F.) Process. See page 146. 
 Siemens Regenerative Furnace. See page 310. 
 Siemens Reversing Process. Regenerative Heating. 
 Siemens Squeezer. See page 377. 
 Siemens Steel; Siemens-Martin Steel. Open hearth steel, either 
 
 acid or basic. 
 Silex (obs.). Silica. 
 Silfrax. See page 398. 
 Silhouette. See page 126. 
 Silica; Silica Brick. See page 395. 
 Silicate. A combination of silica with some base. 
 Siliceous Clay. See page 396. 
 Siliceous Ore. See page 243. 
 Siliceous Rocks. See page 395. 
 Silicide of Carbon. See page 398. 
 Silicized Carbon. See page 398. 
 Silico-Calcium. A product of the electric furnace intended to be 
 
 used as a deoxidizing addition for steel; an analysis shows: 
 
 Silicon 66 .98 % 
 
 Sulphur tr. 
 
 Phosphorus o . 056 
 
 Calcium 27.50 
 
 Aluminum 2.31 
 
 Iron 0.41 
 
 Magnesium tr. 
 
 Manganese nil 
 
 Moisture 0.13 
 
 Silico-Ferrite. See page 272. 
 
 Silico-Ferro-manganese; Silico-manganese. See page 354. 
 
436 SILICO-M AN GANESE SIMPLE INDUCTION 
 
 Silico-Manganese Steels. See page 452. 
 
 Silico-Spiegel; Silicon Spiegel. See page 354. 
 
 Silicon. Si; at. wt, 28; melt, pt, 1200 C. (2192 F.); sp. gr., 
 amorphous, 2.15, crystalline, 2.34 to 2.49. It is always found 
 combined with oxygen as silica (sand) or a silicate. When 
 pure it is a white metal, and, depending upon the method of 
 preparation, may be amorphous or crystalline. "From dif- 
 ferences that have been discovered, and from the close analogy 
 that exists between silicon and carbon, it was at one time believed 
 that three allotropes of this element existed, corresponding 
 to those of carbon. Amorphous silicon was considered to 
 represent charcoal. A crystalline substance obtained by Wohler, 
 by heating potassium silico-fluoride with aluminum, has been 
 regarded as corresponding to graphite, and called graphitic 
 silicon (graphitoidal silicon); while the octahedral crystals 
 of silicon prepared by other reactions (Deville) were thought 
 to be the analogue of the diamond; and this substance has 
 therefore been called diamond silicon or admantine silicon" 
 (Newth). Silicon combines with iron to form a silicide (iron 
 silicide) FeSi 2 . It is always a constituent of pig iron; if higher 
 than about 6% it is called ferro-silicon <see page 354) in which 
 form it is valuable as a deoxidizer (see page 394). In ordinary 
 steel it is usually under about 0.030%; in steel castings it is 
 generally under about 0.25%; while for certain purposes it 
 may go as high as 1.00%. It is now recognized that it has 
 no deleterious influence up to at least 1.00% and probably 
 higher, and has only a slight effect in the amounts usually 
 met with. In molten pig iron it lowers the saturation point 
 for carbon, and during cooling tends to throw it out as graphite. 
 For influence on corrosion: see page 366. 
 
 Silicon Additions. See Recarburization. 
 
 Silicon-Calcium -Aluminum. See page 354. 
 
 Silicon Carbide. See page 398. 
 
 Siliconeisen. See page 354. 
 
 Silicon Ore. See Codorus. 
 
 Silicon Steels. See page 452. 
 
 Siliciuration. See page 66. 
 
 Silit. See page 398. 
 
 Silky Fracture. See page 178. 
 
 Sill. The bottom of the door of a reverberatory furnace. 
 
 Silocel Brick. See page 396. 
 
 Siloxicon. A trade name given to a highly refractory compound of 
 silcon, carbon, and oxygen, having the formula Si 2 C 2 O produced 
 in the electric furnace. 
 
 Silundum. See page 398. 
 
 Silvery Gray Iron; Silvery Iron; Pig. See page 343. 
 
 Similarity. Law of: see page 473. 
 
 Simple Alloy. See Alloy. 
 
 Simple Axial Stress. See page 332. 
 
 Simple Beam. See page 468. 
 
 Simple Cells. See page 121. 
 
 Simple Induction Furnace. See page 153. 
 
SIMPLE MATHEMATICAL RATIO SKEW ROLLS 437 
 
 Simple Mathematical Ratio. Law of for crystals: see page 120. 
 
 Simple Metals. See page 125. 
 
 Simple Microscope. See page 285. 
 
 Simple Overstrain. See page 282.- 
 
 Simple Radical. See page 87. 
 
 Simple Shear. See page 337. 
 
 Simple Slip. See page 283. 
 
 Simple Stress. See page 332. 
 
 Simple Twinning. See page 124. 
 
 Simpson Weld. See page 504. 
 
 Singles. Of sheets: page 430. 
 
 Single Acting Hammer. See Hammer. 
 
 Single Blow Test. See page 481. 
 
 Single Coil. See Coil. 
 
 Single Furnace. See page 376. 
 
 Single Level Furnace. See page 312. 
 
 Single Melting Process. See page 75. 
 
 Single Microscope. See page 285. 
 
 Single Mill. See page 430. 
 
 Single Puddling Furnace. See page 376. 
 
 Single Refined Iron. See page 378. 
 
 Single Rolled Iron. See page 378. 
 
 Single Shear. See page 337. 
 
 Single Shear Heat. See page 71. 
 
 Single Shear Steel. See Shear Steel. 
 
 Single Skip, See page 33. 
 
 Single Steel. See page 430. 
 
 Single Strand (Strip) Coil. See Coil. 
 
 Sink Hole. See page 53. 
 
 Sinker. See page 509. 
 
 Sinkhead. See pages 56 and 299. 
 
 Sinking. See page 79. 
 
 Sinking Fire. A forge in which wrought iron scrap or refined pig is 
 
 partially melted or welded together by means of a charcoal fire 
 
 and a blast (Raymond). 
 Smking Head. See page 56. 
 Sinking a Lump. See page 79. 
 
 Suiter. (i) To fuse: see page 45; (2) cinder: see Slag. 
 Size of Crystals; Grains. See pages 121 and 213. 
 Size of a Rolling Mill. See page 410. 
 Sizing. See Ore. 
 Sizing Rolls. See page 490. 
 Skelp; Skelper. See page 489. 
 Skeletal Crystal; Skeleton Crystal. See page 122. 
 Skeller; Skellering (Yorkshire). The warp sometimes produced in 
 
 a piece of steel when quenched; also for castings on annealing. 
 Skelp; Skelper; Skelping. See page 489. 
 Skew Back. That part of the roof of a furnace at which the spring 
 
 of the arch starts. 
 Skew Plate. See page 135. 
 Skew Rolls ; Rollers. A series of rollers, set at a slight angle to "the 
 
 longitudinal direction of the table, for handling bars or other 
 
438 SKIMMER SLAG 
 
 small rolled products; the effect of the angle is to throw the 
 pieces to one side where they are assembled against a guard. 
 
 Skimmer. See page 36. 
 
 Skin. (i) In an ingot, the layer of metal between the blow- 
 holes and the outside; (2) in a forged or rolled piece, the thin 
 outside layer which has a very fine structure due to the work 
 and the chilling action of the machine. 
 
 Skin Annealing. See page 232. 
 
 Skin Breakage. See Cold Working. 
 
 Skin Dried. See page 298. 
 
 Skin Hardening. See page 69. 
 
 Skip; Skip Bridge; Skip Charging. See page 33. 
 
 Skull. Sometimes spelled scull; (i) the steel or cast iron which has 
 solidified against the inside surface of a ladle, or to remove the 
 same; (2) in a blast furnace: see page 35. 
 
 Skull Breaker; Cracker. A heavy ball or piece of metal, with the 
 necessary appliances, which is raised and dropped on a skull or 
 other large piece of metal to reduce it to a size convenient for 
 handling. 
 
 Slab. See page 411. 
 
 Slab Ingot. See page 53. 
 
 Slabbing Mill. See page 413. 
 
 Slack. (i) See Coal; (2) of lime: see page 396. 
 
 Slag. Also called cinder or sometimes scoria; the molten sub- 
 stance, other than the metal under treatment, consisting of acid 
 or basic oxides which may be composed (a) in smelting, operations, 
 of the gangue of the ore combined with some fluxing material 
 (usually lime) added to render it fusible and easily separated 
 from the metal, and also to effect a certain amount of purification, 
 or (b) in purifying processes, of substances (usually lime and iron- 
 oxide) introduced for the purpose of effecting or assisting in the 
 purification. A slag which is infusible or pasty is sometimes 
 called a dry slag; one which is fusible and liquid, a wet slag. 
 A scouring cinder is one, generally high in oxide of iron, which 
 is very liquid and attacks and corrodes the lining of a furnace. 
 A slag is acid or basic depending upon whether the principal 
 constituent is respectively silica, or lime or oxide of iron. A 
 bastard slag is the name sometimes applied (a) to a slag in a 
 basic furnace which is not sufficiently basic, or (b) to a slag in 
 an acid furnace to which lime has been added (usually toward 
 the end of tlje heat) with the idea of effecting a slight elimination 
 of phosphorus. A preliminary slag is (a) the slag existing 
 shortly after the commencement of a refining process, or (6) 
 that which is tapped out before the end of the process: in blast 
 furnace work this is termed roughing cinder or flush; in pud- 
 dling, boilings. A final slag is the slag existing at the end of 
 a process, or what is tapped out at that time, usually called 
 tapping slag; in puddling, tappings or tap cinder; puddling 
 furnace cinder is rarely called mill cinder or mill tap. Drop 
 is an obsolete name for the slag collected at ..the bottom of the 
 hearth of a Catalan forge, or puddling furnace. The term 
 reaction slag has been applied to that found in steel resulting 
 
SLAG-BEARINGSLAG PROCESSES 439 
 
 from a chemical reaction while molten as distinguished from that 
 found in the furnace (furnace slag) during the process, particles 
 of which may be mechanically retained in the metal during 
 solidification. The slag expelled under a hammer from a ball or 
 lump of wrought iron after drawing from the furnace is called 
 hammer slag or forge cinder. In England blacksmith's slag is 
 sometimes called hards. The slag very rich in oxides of iron 
 formed by the oxidation of the iron in reheating furnaces is 
 called heating furnace cinder or flue cinder. Buckshot cinder is 
 blast furnace slag containing small particles of metallic iron. 
 Tarmac (Eng.) is slag treated while hot with molten tar or pitch 
 and used as a road-making material. 
 
 Slag-bearing. Containing slags, as wrought iron. 
 
 Slag Bottom. See Lining. 
 
 Slag Bottom Process. See page 78. 
 
 Slag Brick. See Slag Cement. 
 
 Slag Cement. (i) Granulated or ground blast furnace slag mixed 
 with slaked lime, referred to specifically as blast furnace slag 
 cement; (2) a regular Portland cement in which blast furnace 
 slag is used as the base. Greiner gives the following description 
 of the manufacture (/. /. 6* S. Inst., 1914, i, 45+): a mixture of 
 75% of granulated slag and 25% of lime is fritted in the kilns 
 usually employed in the Portland cement industry; by these 
 means there are obtained nodules, or semi-fused agglomerates, 
 possessing a special molecular texture and termed clinker. A 
 mixture of 70% clinker and 30% granulated slag, finely ground, 
 yields a cement of superior quality known in Germany as Eisen- 
 Portland, and accepted during the last five years, under the same 
 category as Portland cement, by public administrations and 
 the International Sales Syndicate. The granulated slag mixed 
 with a small percentage of slaked lime is put under presses, and 
 slag bricks thus formed, and heated in autoclaves (pressure 
 chambers) under steam at a pressure of one to eight atmos- 
 pheres, acquire a remarkable degree of hardness. Uniformity of 
 shape and a pleasing appearance create a demand for all kinds of 
 masonry work which they render drier and more impervious to 
 moisture than ordinary brick. 
 
 Slag Formation, Zone of. See page 36. 
 
 Slag Inclusion. See page 57. 
 
 Slag Ladle. See Ladle. 
 
 Slagless. Free from or containing only accidental traces, as steel 
 produced in the fluid condition. 
 
 Slag Line. In the crucible process: see page 115; (2) in the open 
 hearth process: see page 311. 
 
 Slag Machine. A machine for handling the slag from a blast fur- 
 nace. It usually consists of a series of shallow iron pans in an 
 endless chain on which the slag is chilled with sprays of water, 
 after which it is dumped into cars. 
 
 Slag Notch. See page 32. 
 
 Slag Pit. See page 312. 
 
 Slag Pocket. See page 311. 
 
 Slag Processes. See page 384. 
 
440 SLAG SHORT SNAKE 
 
 Slag Short, Shortness. See Brittleness. 
 
 Slag Wool. Also called mineral wool; it is a downy fibrous sub- 
 stance, somewhat resembling wool, produced by blowing a jet 
 of steam of air against a small stream of molten slag. A similar 
 substance, made from lime and silicious rocks melted together, is 
 called rock wool. 
 
 Slake. See page 396. 
 
 Slaty Fracture. See page 178. 
 
 Slaviankoff Process. See page 503. 
 
 Slavianoff Electric Casting. See page 65. 
 
 Sleazy (Eng.). Usually referring to fabrics but sometimes applied 
 to iron or steel objects, particularly sheets, which are weak or 
 lacking in body. 
 
 Sledge. See Hammer. 
 
 Sleeve Brick. See Ladle. 
 
 Slick Angular Method. Of rolling: see page 420. 
 
 Slip. (i) Of a blast furnace: see page 35; (2) of metals: see page 
 282. 
 
 Slip Band; Theories. See page 282. 
 
 Slip Fracture. See page 179. 
 
 Slip Plane; Slipping Plane. See pages 123 and 282. 
 
 Slitting Mill; Pass. See page 419. 
 
 Sliver. A very thin piece of metal rolled into the surface of a 
 piece to which it is attached by only one end. 
 
 Slopping. See page 21. 
 
 Slow Cement. See page 67. 
 
 Slow Combustion. See page 202. 
 
 Slow Pouring. See page 59. 
 
 Slow Test. See page 468. 
 
 Sludge. See page 33. 
 
 Small Billet. See page 411. 
 
 Small Calorie. See page 199. 
 
 Smelt. To extract the metal or metals from an ore in a furnace 
 by reduction, usually by means of solid carbonaceous matter, 
 such as coal, coke, or charcoal, whicty also supplies the necessary 
 heat. This term should be carefully distinguished from melt, 
 which signifies simple fusion, for which it is sometimes incorrectly 
 used. 
 
 Smelter Coke. See page 97. 
 
 Smith -Casson Process. See page 61. 
 
 Smith Coal; Smithy Coal. See Coal. 
 
 Smith (Wm.) Process. See page 232. 
 
 Smith's (Angus) Solution. See page 365. 
 
 Smiths' Tool Temper. See Temper. 
 
 Smithing (Eng.). See Forging. 
 
 Smithy Slack (obs.). Hammer scale. 
 
 Smithy Test (Eng.). See page 476. 
 
 Smoke. See page 202. 
 
 Smoky edged Plate. See page 432. 
 
 Smooth Fracture. See page 178. 
 
 Smyth Process. See page 388. 
 
 Snake. See Seam. 
 
SNARLING SOLUTION 44 1 
 
 Snarling. See page 476. 
 
 Snelus Process. See page 147. 
 
 Snipping (Eng.). Chipping off, as with a tool struck by a hammer. 
 
 Snyder Furnace. See page 163. 
 
 Soaking; Soaking Furnace; Soaking Pit; Soaking Pit Process. 
 Seepage 184. 
 
 Sodium. Na; at. wt., 23; melt, pt, 97.6 C. (207.7 F.); sp. gr., 
 0.97. It is never found in nature in the uncombined state. 
 It is a soft white metal readily oxidized. The oxide and the 
 carbonate have a very limited application as a flux, but prac- 
 tically never in the metallurgy of iron and steel. 
 
 Sodium Picrate. As an etching medium: see page 287. 
 
 Soft Annealing. See page 232. 
 
 Soft Blast. Blast which is weak or low in pressure. 
 
 Soft Centered Steel. See page 64. 
 
 Soft Coal. See Coal. 
 
 Soft Coke. See page 97. 
 
 Soft Roll. See page 403. 
 
 Soft Solder. See page 505. 
 
 Soft Spot. See Hard Spot. 
 
 Soft Steel. See page 455. 
 
 Softener. See page 347. 
 
 Softening Point. See page 396. 
 
 Soldering. See page 505. 
 
 Sole. (i) The hearth of a furnace: see page 183; (2) the bottom or 
 bottom surface. 
 
 Sole Plate. A plate placed under the bottom or sole, as of a 
 furnace; a rail. 
 
 Solid. (i) The condition of being solid or not readily mobile, as 
 contrasted with liquids and gases; (2) sound; free from cavities, 
 such as blowholes or pipe;*(3) in one piece, as solid steel wheel; 
 (4) see page 81. 
 
 Solid Cement. See pages 67 and 68. 
 
 Solid Contraction. See page 53. 
 
 Solid Ingots. See page 59. 
 
 Solid Solution (adj., Solid Solubility). See page 270. 
 
 Solid State. See page 81. 
 
 Solidification. See pages 53 and 266. 
 
 Solidification Point. See page 201. 
 
 Solidification Range. See pages 54 and 267. 
 
 Solidified Solution. See page 270. 
 
 Solidoid. See page 270. 
 
 Solidus; Solidus Curve. See pages 268 and 270. 
 
 Solubility Curve. See Curve. 
 
 Solute. See pages 83 and below. 
 
 Solution. In the ordinary sense a homogeneous mixture of either 
 a gas, a liquid, or a solid wkh a liquid, this liquid being termed 
 the solvent (Newth) and the dissolved substance the solute. 
 A saturated solution is one which contains the maximum amount 
 of a given substance which can be dissolved under the given condi- 
 tions; it is supersaturated when there is more in solution than can 
 normally exist, or, in other words, it is in unstable equilibrium. 
 
442 SOLUTION PLANE SPECIAL HEAT TREATMENT 
 
 A solubility curve is a diagram showing the different concentra- 
 tions for changes in temperature and (sometimes) in pressure. 
 Solution pressure is the energy with which molecules seek to 
 leave the solid state and go into solution. The coefficient of 
 distribution is the proportion of a third substance dissolved by 
 each of two other substances, both of which are in contact with it 
 and with each other. Diffusion is the tendency of a solution to 
 mingle with one more dilute, or of different composition, until 
 the mixture is homogeneous or of uniform composition through- 
 out; this is the reverse of segregation. Osmose is the diffusion 
 of a crystalline body in solution, or of two different solutions, 
 through a porous membrane or diaphragm. The passage from 
 the side on which it was originally is called exosmose; that to the 
 other side, endosmose. The pressure exerted thereby on the 
 membrane is known as osmotic pressure. A substance which 
 will not so diffuse is called a colloid. 
 
 Solution Plane. See page 127. 
 
 Solution Pressure. See Solution. 
 
 Solution Theory. Of hardening: see page 279. 
 
 Solvent. See Solution. 
 
 Solvite. See page 273. 
 
 Sonim. See page 279. 
 
 Sonority Test. See page 483. 
 
 Sorbite. (i) In metallography: see page 276; (2) a name formerly 
 given to ruby and blue crystals found by Sorby, and only in 
 certain cast iron, which were shown to be nitride of titanium. 
 
 Sorbitic Pearlite. See page 273. 
 
 Sorbitic Steel. Steel containing a large proportion of sorbite. 
 
 Sorbitism. See page 277. 
 
 Sorby's Reagent. For etching: see page 287. 
 
 Sorting. See Ore. 
 
 Sound. Free from defects, particularly pipes and blowholes. 
 
 Sound Steel. See page 59. 
 
 South Wales (Welsh) Process. See page 79. 
 
 Sow; Sow Metal. See page 342. 
 
 Space -Lattice; Theory. See page 121. 
 
 Spall. (i) Of bricks, etc., when they are easily abraded; (2) of car 
 wheels, shelling out: see page 357; (3) of cast iron rolls, when 
 particles crack or flake out of the surface. 
 
 Spangle. See page 431. 
 
 Spanner. See page 406. 
 
 Spar. Fluorspar: see Flux. 
 
 Spark Test. See page 484. 
 
 Sparry Ore. See page 244. 
 
 Spathic; Spathose; Spathous. Having an even lamellar or flatly 
 foliated structure (Cent. Diet.). 
 
 Spathic Carbonate; Iron Ore; Ore. See page 244. 
 
 Spawl. See Spall. 
 
 Special Additions. See Recarburization. 
 
 Special Cast Iron. See page 351. 
 
 Special Ferro-Silicon. See page 354. 
 
 Special Heat Treatment. See page 212. 
 
SPECIAL HIGH SILICON SPECIAL STEELS 443 
 
 Special High Silicon Iron. See page 354. 
 
 Special Long Ton. See Ton. 
 
 Special Low Phos.; Low Phosphorus Pig. See page 346. 
 
 Special Open Hearth Processes. See page 315. 
 
 Special Steels. Also called alloy steels, or combination steels, 
 and rarely, alloyed carbon iron, are steels which owe their 
 properties chiefly to the presence of an element or elements 
 other than carbon (I.A.T.M.). If the carbon is over about 2% 
 they are usually termed ferro-alloys (?.., page 351). The ele- 
 ments (alloy elements) principally concerned are nickel, chro- 
 mium, vanadium, tungsten, molybdenum, manganese (over 
 about 7%), and silicon (over about 0.5%). In contradistinc- 
 tion to the above, steel which owes its properties chiefly to vari- 
 ous percentages of carbon is known as ordinary steel or carbon 
 steel. In a general sense carbon steels which are prepared for 
 some specific purpose are sometimes spoken of as special steels, 
 but this is not the customary practice. In this class might be 
 included what Longmuir calls high tension steels, a term which 
 he employs to cover endurance to reversal of stresses as well as 
 actual high tensile strength; in other words steels possessing high 
 resistance to service conditions (more properly high resistance 
 steels) which are not usually limited to tensile stresses. Quality 
 steels (Eng.) are those of high quality intended for special pur- 
 poses, and not necessarily containing special elements. Ternary 
 steels are those which consist chiefly of iron, carbon, and one 
 other special element; quaternary steels, of iron, carbon, and two 
 other special elements. 
 
 Guillet's Theory of Ternary Steels. Sauveur explains this as 
 follows (Metallography, 326-7): "Too rigorous an application of 
 the theory, however, should not be insisted upon for there are 
 some facts not yet satisfactorily explained by it. Its use, never- 
 theless, will be found an invaluable guide in directing researches 
 dealing with the manufacture and the application of these 
 steels. 
 
 "Guillet's theory of the structure and properties of ternary 
 steels may be briefly formulated by a few propositions. It is 
 also represented graphically in Fig. 59. 
 
 " (i) On the introduction of a special element in carbon steel the 
 latter remains at first pearlitic, but as the proportion of special 
 element increases, the carbon remaining constant, it becomes 
 first martensitic and then austeni tic (polyhedral), as shown graph- 
 ically in Fig. 59, and sometimes called cementitic (carbide steel) 
 as later explained. 
 
 "(2) By increasing the amount of carbon present in a special 
 steel, the proportion of the special element being kept constant, it 
 is generally converted from a pearlitic into a martensitic condi- 
 tion or, if already martensitic, into an austenitic condition. 
 "(3) The greater the amount of carbon the smaller the pro- 
 portion of the special element needed to cause a structural 
 transformation, as for instance pearlite into martensite or marten- 
 site into austenite. This is indicated in Fig. 59. 
 " (4) The greater the amount of the special element the smaller 
 
444 
 
 SPECIAL STEELS 
 
 the proportion of carbon needed to cause a structural transforma- 
 tion. This is also 'shown in Fig. 59. 
 
 " (5) No very sharp lines of demarcation are observed between 
 the different types of structures mentioned in the preceding 
 propositions, relatively wide ranges of composition existing, on 
 the contrary, in which the steel may be partly pearlitic and partly 
 martensitic or partly martensitic and partly austenitic, etc. 
 These transition ranges are indicated by shaded areas in the 
 diagram of Fig. 59. Greater refinement in the construction of 
 this diagram would undoubtedly lead to the introduction of a 
 troostitic zone between the pearlite and martensite areas and 
 possibly also of a sorbitic zone between pearlite and troostite. 
 
 "To sum up, constituents may be formed during the slow 
 cooling of many alloy steels which in carbon steels can only be 
 produced by very rapid cooling through the critical range. 
 
 .6 .8 1.0 
 
 Per cent Carbon 
 
 PIG. 59. Ternary steels. (Sauveur} . 
 
 Carbon steels, moreover, even after very rapid cooling cannot 
 be retained wholly in an austenitic condition while several 
 special steels remain austenitic after slow cooling It is evident 
 from the above and from the diagram that in order to produce a 
 certain structure, (i) the proportion of carbon may^ be kept 
 constant while the proportion of the special element is increased 
 until the desired structure is obtained, or (2) the proportion of 
 the special element may be kept constant and the proportion 
 of carbon increased, or (3) both the proportion of carbon and of 
 the special element may be increased when the desired structure 
 will be obtained more quickly." 
 
 Constitution of Special Steels. As stated in Guillet's theory 
 the normal condition of special steels at ordinary temperatures 
 is dependent primarily upon the nature and amount of the special 
 element or elements in conjunction with the percentage of carbon 
 
SPECIAL STEELS 445 
 
 and the heat treatment. Based on ordinary or slow cooling a 
 classification may be made into: 
 
 1. Pearlitic steels: Similar to carbon steels, and, as a rule, 
 relatively low in special elements. "In these steels the special 
 element may (i) be dissolved in the ferrite forming with it a solid 
 solution, (2) be combined with carbon in cementite as a double 
 carbide of iron and the special element, or (3) be partly dissolved 
 in ferrite and partly combined with carbon. According to 
 Guillet nickel and silicon, for instance, are entirely dissolved in 
 ferrite, while manganese, chromium, tungsten, vanadium, and 
 molybdenum are partly held in solution by ferrite and partly 
 present in cementite as double carbides" (Sauveur, Metallography, 
 331). " Guillet writes that pearlitic special steels may be divided 
 into (i) those that are not very sensitive to annealing, namely, 
 nickel and silicon steels, and (2) those that are very sensitive to 
 annealing, namely, manganese, chrome, vanadium, tungsten, and 
 molybdenum steels. It should be noted that in the first group 
 the special elements are supposed to be entirely dissolved in the 
 iron, while in the second group they are partly dissolved and 
 partly present as carbides" (Sauveur, ibid., 333-4). 
 
 2. Martensitic steels: With a higher combination of special 
 elements and carbon than the preceding; except by very slow 
 cooling they are hard, and are not affected by ordinary tempering 
 operations. 
 
 3. Austenitic (polyhedral) steels : With a still higher combina- 
 tion of the special elements and carbon. They are non -magnetic 
 as, for example, in the case of n % manganese steel or 25 % 
 nickel steel. Sauveur points out (ibid., 334) that air cooling 
 may be required to produce truly austenitic steels; with slower 
 cooling particles of carbide may separate out, and to cause 
 reabsorption the steel is reheated to a high temperature 
 followed by oil or water quenching, the latter termed water 
 toughening. 
 
 4. Cementitic (carbide) steels: "Some special elements on 
 being introduced in increasing proportions fail to convert the 
 metal into austenite, free particles of a double carbide of iron and 
 the special element being formed instead and embedded in a 
 martensitic, troostitic, sorbitic, or pearlitic matrix. Guillet calls 
 these carbide steels. Such elements as chromium, tungsten, 
 molybdenum, and vanadium when present in sufficient quantity 
 produce cementitic steels" (Sauveur, ibid., 333). 
 
 Special elements were first used in the manufacture of steel 
 for machine tools (tool steel), which was then called special 
 tool steel to distinguish it from the ordinary tool steel or carbon 
 tool steel formerly made exclusively. Mushet found that 
 a steel containing about 1.50% of carbon and 5 to 8% of tungsten 
 (a) would be rendered sufficiently hard by simple cooling in air 
 (sometimes an air blast is employed) and (b) that the edge or 
 temper of such a tool would remain practically intact at a temper- 
 ature approaching a visible red, and as a result the tool would 
 take a faster or a heavier cut. For these reasons such steels have 
 been denominated Mushet steel, air-hardening steel, air- 
 
446 SPECIAL STEELS 
 
 quenched steel, self-hardening steel, high speed steel, quick 
 speed steel, or rapid tool steel (rarely natural steel). 
 
 Taylor and White experimented with tool steels to obtain 
 greater efficiency, and the method of treatment which they 
 developed (Taylor-White process) improves nearly all kinds 
 of special tool steel. Steel so treated is sometimes termed 
 Taylor-White steel, high heat tools, or modern high speed 
 tools, but as the method of treatment is the principal factor, 
 these gentlemen object to the name new tool steel as being 
 misleading. The proces consists of two steps: 
 
 1. The first or high heat treatment: 
 
 (a) heating slowly to 1500 F. (816 C.); 
 (6) heating rapidly from that temperature to just below 
 the melting point; 
 
 (c) cooling rapidly to below 1550 F. (843 C.); and 
 
 (d) cooling either rapidly or slowly from that point to 
 the temperature of the air. 
 
 2. The second or low heat treatment: 
 
 (e) heating to a temperature below 1240 F. (671 C.), 
 preferably to 1150 F. (621 C.), for about 5 minutes; 
 and 
 
 (f) cooling either rapidly or slowly to the temperature of 
 the air. The second treatment may also be produced 
 by running the tool hot, and then cooling it down. 
 Between 1550 and 1700 F. (843 and 927 C.) they 
 term the breaking down temperature, as ordinary 
 tool steel, if heated within this range, is seriously 
 injured or broken down in its cutting speed. Red 
 hardness is the name they give to the property of 
 a tool when it maintains its cutting edge after its 
 nose is red hot, obtained with chrome-tungsten steels 
 (containing not less than 0.5 % of chromium and i % 
 of tungsten or its equivalent) by heating them close 
 to their melting point. They have published the 
 following representative analyses (the range in com- 
 position for many self-hardening steels was commu- 
 nicated to Howe by J. A. Matthews) : 
 
 Mushet Original Best Modern 
 Jessop Self- Taylor- High Speed Range 
 Harding White 1906 
 
 Tungsten 5 .441 8.00 18.91 3.44^24.00 
 
 Chromium... 0.207 0.308 3.80 5-47 o.ooto 6.00 
 
 Carbon 1.047 *5o 1.85 0.67 0.40 to 2.19 
 
 Manganese.. 0.189 1.578 0.30 o.n 
 
 Vanadium o . 29 
 
 Silicon 0.206 1.044 o- J 5 o-43 0.21 to 3.00 
 
 Phosphorus.. 0.017 0.025 
 
 Sulphur 0.017 0.030 
 
 E. K. Hammond states that the following is representative of the 
 composition of the early Mushet steel: tungsten, 9.0%; manga- 
 nese, 2.5%; carbon, 1.85%. 
 
SPECIAL STEELS 447 
 
 In the paper on "The Effect of Chromium and Tungsten upon 
 the Hardening and Tempering of High-Speed Tool Steel" 
 (J.I. 6*5.7., 1915, ii, 29, 30), Ed wards and Kikkawa reached the 
 following conclusions: 
 
 "i. The first effect of tempering hardened high-speed steels 
 it to make them softer, but when they are tempered at higher 
 temperatures they again become harder, and after heating at or 
 about 614 C. (1137 F.) they are much harder than in the initial 
 air-quenched state. There can be no doubt that this secondary 
 hardening is the cause of the improved cutting powers of a tool, 
 which Mr. Taylor found was brought about by a secondary low 
 heating to about 620 C. 
 
 "2. Chromium in conjunction with carbon is the cause of the 
 great hardness of hardened high-speed steels, and further, it 
 materially lowers the temperature at which these steels can be 
 air-hardened. 
 
 "3. In the absence of chromium, tungsten raises the tempera- 
 ture at which tempering or annealing begins, and in the presence 
 of chromium it increases the intensity of the secondary hardening, 
 and raises the tempering temperature. 
 
 "4. Tungsten steel containing 18.0% of tungsten and 0.63% 
 of carbon can be air-hardened only by rapid air-quenching from 
 temperatures above 1050 C. (1920 F.). 
 
 "5. When high-speed steels are hardened at low temperatures, 
 say 1050 C., the tempering properties approximate to those of a 
 pure chromium steel, by softening at a low temperature, and 
 developing little or no secondary hardening. This is due to the 
 tungsten being undissolved and remaining inactive. 
 
 "6. The maximum resistance to tempering and the greatest de- 
 gree of secondary hardening can only be obtained by getting the 
 tungsten into solution, and with modern high-speed steels this is 
 not complete until a temperature of about 1350 C. (2460 F.) 
 is reached. 
 
 "7. Specific gravity determinations seem to indicate that there 
 is a direct connection between the hardness and volume of these 
 steels. On tempering, an increase of hardness is accompanied by 
 an increase in volume." 
 
 By secondary hardening, referred to above, is meant that 
 resulting from the reheating or tempering of high-speed steels 
 after a preliminary or initial hardening, which in contradistinction 
 would also be termed primary hardening. Edwards has also 
 employed the term critical cooling velocity to indicate the rate of 
 cooling which must be maintained if self-hardening is to result. 
 In connection particularly with tungsten steels it has been found 
 that the higher the temperature for the primary treatment the 
 lower would be subsequently the Aci point; this has been termed 
 the lowering temperature. 
 
 The following is an abstract (/. 7. & S. I., 1915, i, 605 taken 
 from Gassier' s Eng. Monthly): "The high-speed steels of the 
 present day are combinations of iron and carbon with tungsten 
 and chromium; molybdenum and chromium; tungsten, chromium, 
 and vanadium j tungsten, molybdenum, chromium, and rana- 
 
448 SPECIAL STEELS 
 
 dium. The control of the carbon limits is a very important 
 matter. The best results are obtained from steels containing 
 0.5 to 0.7% of carbon. Higher percentages are not desirable, 
 because great difficulty is experienced in forging the steel. 
 With from 9 to 16% of tungsten and in conjunction with chro- 
 mium the nature of the steel becomes very brittle, but at the 
 same time the cutting efficiency is greatly increased. Sixteen 
 percent of tungsten appears to give maximum hardness. The 
 presence of chromium in high-speed steel varies from i to 6%. 
 While a large percentage of tungsten is necessary in a good steel, 
 it has been found that as low as 5 % of molybdenum will make 
 an excellent steel. Molybdenum steels do not require such a 
 high temperature in hardening as do the tungsten steels. The 
 presence of i% of vanadium in a high-speed steel, containing 
 at least 18% of tungsten, enables such a steel to be quenched 
 from a white heat in water without cracking, and this fact led 
 to the recent production of water-hardening high-speed steels ; 
 but it must be borne in mind that the percentage of carbon 
 must not exceed 0.6%, otherwise there is danger of cracking 
 in the operation of hardening." 
 
 In regard to the effect of heat treatment on density of alloy 
 steels the same abstract as already quoted from (see Heat 
 Treatment, page 224) states: "In alloy steels the difference 
 in density as between water-hardened and oil-hardened steels 
 is not nearly so great as in the case of ordinary carbon steels. 
 Quenched alloy steels show no maximum at 430 C. (805 F.), 
 but from that temperature upwards the density increases con- 
 tinually. Eutectoid steels tend more than others to develop 
 hardening cracks, on account of their greater volume changes 
 during quenching. Bars increase in length according to. the 
 carbon content, and the increase is proportional to the length 
 of the bar. When quenched from 960 C. (1760 F.) several of 
 the special steels always gave hardening cracks, so that the 
 specific gravity could not be determined. The nickel and chro- 
 mium steels show a smaller increase in volume with quenching 
 than plain steels of the same carbon content. This is also 
 true of the manganese steels, although not to so great an extent, 
 while the chromium-nickel steels show a proportionally great 
 change of volume. Although these results do not apply to all 
 special steels, yet it is certain that through suitable special 
 additions the change in volume due to quenching can be greatly 
 reduced. The author considers that the change in volume 
 brought about by quenching steel is only small if the quenching 
 temperature be within a limit close to the critical temperature. 
 Very great changes in volume are brought about if this limit is 
 even slightly exceeded." 
 
 The special steels in common use contain one or more of the 
 elements (in addition to carbon and manganese) nickel, chrom- 
 'ium, silicon, and vanadium. With the exception of nickel steel 
 (for certain structural purposes, such as bridges) they are usually 
 given a special heat treatment to develop as far as possible 
 the properties which warrant their extra cost. The following 
 
SPECIAL STEELS 
 
 449 
 
 V 
 
 H & 
 
 
 
 
 
 S 
 
 O 
 
 
 
 * 
 
 .H-a 
 
 IO 
 
 
 a 
 
 | 
 
 S 8 
 
 %% 
 
 10 O O 00 O 
 
 
 
 <J 
 
 > 
 
 
 
 
 
 
 jk^ 
 
 
 
 ? ?! ? 
 
 
 o 
 
 c 
 
 =1 
 
 ro O O 
 
 o o 
 
 
 
 
 &s 
 
 V IH 
 
 
 
 
 
 -o S 
 
 
 * 
 
 
 |g 
 
 ??? 
 
 
 
 
 
 %0 0- ^-g M 
 
 
 
 
 ro 
 
 o 
 
 
 
 
 65 
 
 IO IO IO 
 
 
 
 
 to 
 
 l^ cs O\ 
 
 
 w 
 
 1 
 
 1u 
 
 loo T 1 
 
 
 
 "M 
 
 
 10 10 o 
 
 
 
 3 
 
 IO 
 
 rfr o t- vO 
 O NO 
 
 Q* 
 
 
 _o 
 
 N 
 
 
 H 
 
 
 'S 
 
 i 
 
 6? 
 
 S ON 
 
 
 
 s 
 
 
 
 IO 
 
 
 Q 
 
 1 
 
 o 
 
 
 fO O O 10 \ 
 
 
 
 
 ^ 
 
 O MO 
 
 
 
 
 g5 
 
 O to ' 
 
 
 
 
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 00 IO t- 
 
 
 
 
 10 
 
 1O 
 
 
 O 
 
 
 
 O ^t ^ M O 
 
 i JL ' 
 
 
 
 
 
 
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 to O O * 
 
 
 
 
 o 
 
 MO 
 
 
 M 
 
 3 
 
 
 00 V 
 
 o "i- * c o 
 
 1 O O 3 O 
 
 
 
 s 
 
 
 10 o o o n 
 
 
 
 
 
 o & 
 
 
 
 
 
 
 
 
 
 
 hj 
 
 oo 
 
 
 ^ 
 
 , 
 
 c 
 
 3 
 
 2> o o 
 
 
 
 
 
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 1 
 
 
 
 
 
 5 
 
 
 
 
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 U 
 
 
 w ^ ! r 
 
 
 
 M 
 
 
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 1 
 
 
 8 S ; g' S - 
 
 
 
 <U 
 
 S 
 
 
 S 2 ^" -2^ 
 
 1^1 3 l^ 
 
 Jj-3 a .S S 
 
 S OT ^ > 
 
450 SPECIAL STEELS 
 
 table taken from the specifications for forging billets of the 
 A. S. T. M. will serve to illustrate the types and grades (for 
 carbon as well as alloy steels) commonly used for special f orgings 
 of any size (see preceding page). 
 
 Carbon Ranges for the Various Grades for Carbon and 
 Alloy Steel 
 
 Carbon Steel Type A. Alloy Steel Types B to H, Incl. 
 
 Grade Carbon, % Grade Carbon, % 
 
 i 0.05-0.15 ii I.. 0.10-0.20 
 
 2 0.15-0.25 12 0.15-0.25 
 
 3 0.20-0.30 13 0.20-0.30 
 
 4 o . 25-0 .40 14 o . 25-0 . 38 
 
 5 0.30-0.45 15 0.30-0.43 
 
 6 0.35-0.50 1 6 0.35-0.50 
 
 7 0.40-0.55 17 0.45-0.60 
 
 8 o . 45-0 . 60 
 
 NOTE i . When the steel is to be used for case-hardening pur- 
 poses, the manganese should be specified not to exceed 0.50%. 
 When the minimum carbon specified is 0.35 % or over, the man- 
 ganese range may be specified 0.30-0.60%. 
 
 NOTE 2. In selecting billets for making f orgings of Classes K, 
 L and M, as defined in the Standard Specifications for Carbon- 
 steel and Alloy-steel Forgings (Serial Designation: A 18) of the 
 American Society for Testing Materials, it is suggested that the 
 use of steel with a relatively high carbon content will permit the 
 use of a high drawback temperature and thus put the steel in its 
 best physical condition for service, shock and similar conditions. 
 
 Tungsten steels (rarely called wolfram steels), as now made 
 usually contain (Howe) from 5 to 10% (and sometimes even 
 24%) of tungsten, and from 0.4 to 2% of carbon. Tungsten- 
 chrome steels, as used for cutting tools, have been discussed 
 above. There is another class, known as magnet steels (mag- 
 netic steels), which is used for permanent magnets owing to its 
 high retentivity; these contain (Rosenhain) tungsten about 7 % 
 and chromium up to 0.5%. They are usually quenched in oil 
 or water to render them as hard as possible as this is necessary 
 for the purpose (magnetic hardness). Tungsten probably 
 goes into solution as the tungsten iron compound Fe 3 W; in the 
 undissolved form it may exist as Fe 2 W which was isolated by 
 Arnold and Read. 
 
 Molybdenum steels are" somewhat similar in their properties 
 to tungsten steels, and apparently i % of molybdenum is equi- 
 valent to 2% of tungsten (Howe). 
 
 Nickel steels (when no other special elements are present) 
 ordinarily contain from 3 to 4 % (usually not over 5 %) of nickel, 
 from o.io to 0.50% of carbon, and about 0.30 to 0.80% of 
 manganese. This amount of nickel renders the steel much 
 tougher and stiff er; it also raises the ultimate strength and the 
 elastic limit, the latter to a greater extent than the former, and 
 
SPECIAL STEELS 451 
 
 this with an increase in the ductility, the composition other- 
 wise, and the treatment, remaining the same. The 3 to 3^% 
 grade has been used to a considerable extent for structural work, 
 particularly bridges, of which some of the most important 
 have been made partly or almost entirely of this material. 
 With less than 3% nickel the principal application has been 
 for case-hardening purposes. Nickel steel, containing about 
 36% of nickel, patented under the name invar (Guillaume's 
 invar) has a lower coefficient of expansion than any other metal 
 or alloy known and, in consequence, is largely employed for 
 instruments of precision. Another patented alloy, termed 
 platinite, contains about 46 % of nickel, and at ordinary 
 temperatures has the same coefficient of expansion as glass 
 (and platinum), and for this reason is used as a substitute for 
 platinum in the manufacture of incandescent lamps. Types of 
 nickel-chrome steels are shown in table on page 449. Special 
 types of nickel and particularly nickel-chrome steel are used in 
 the manufacture of armor plate and armor-piercing projectiles. 
 
 Chrome steel or chromium steel, "which usually contains 
 about 2% of chromium and 0.80 to 2% of carbon, owes its 
 value to combining, when in the hardened or suddenly cooled 
 state, intense hardness with a high elastic limit, so that it is 
 neither deformed permanently nor cracked by extremely violent 
 shocks. For this reason it is the material generally if not 
 always used for armor-piercing projectiles. It is much used 
 also for certain rock-crushing machinery and for safes. These 
 last are made of alternate layers, usually five in number, of 
 chrome steel and wrought iron, welded together, and then 
 cooled suddenly so as to harden the chrome steel. The hard- 
 ness of the hardened chrome steel resists the burglar's drill, 
 and the ductility of the wrought iron the blows of his hammer" 
 (Howe). More recently types containing a lower chrome 
 content have received wide adoption both for plain chrome steel 
 and in combination with nickel or vanadium (nickel-chrome or 
 chrome -nickel, and chrome-vanadium steels see table, page 
 449). Under the trade name crucia steel a type containing 
 about 0.20 to 0.50% chrome, the same amount of manganese, 
 and about 0.80 to 1.00% carbon has been considerably used 
 for certain automobile springs. A recent patented alloy, called 
 stainless steel, has been introduced for articles of cutlery 
 (especially for fruit) and for rifle and gun barrels owing to its 
 almost complete freedom from ordinary corrosion; it contains 
 about 10 to 15% of chrome and carbon less than about 0.50%. 
 An Austrian steel called non-corro, used for the same purposes, 
 is probably of somewhat similar composition. Chrome steel 
 is rarely referred to as chromated steel. 
 
 Manganese steel (Hadfield's manganese steel, austenitic 
 manganese steel) contains about 12% of manganese and 1.25% 
 of carbon (the manganese is usually between about 11 and 14%) 
 and was discovered by Hadfield in 1883; in 1887 he called it 
 self -hardening steel. Owing to its great hardness it is ordinarily 
 cast nearly to shape and then finished by grinding; it has been 
 
452 SPECIAL STEELS 
 
 successfully rolled into rails. As cast or otherwise produced 
 (with relatively slow cooling) it is extremely brittle and to remove 
 this it is heated to a fairly high temperature (about 1000 C.- 
 1830 F.) and quenched in water. This has the effect of render- 
 ing it tough and ductile without materially altering its hardness 
 (tough hardness), and for this reason the water treatment 
 is known as water toughening. In contradistinction the brittle- 
 ness allied with hardness which would be produced in an ordinary 
 steel equally high in carbon has been called brittle hardness. 
 Treated manganese steel after treatment has a tensile strength 
 of about 54 to 63 tons (about 120,000 to 141,000 pounds) per 
 square inch, and an elongation of 30 to 50%; the stretch is nearly 
 uniform throughout the length tested as very little necking 
 occurs. The Brinell hardness number is about 200, whereas, 
 without such high manganese, ordinary carbon steel would have 
 a hardness number of about 600 to 800. By heating sufficiently 
 long, up to 700 C. (1290 F.), it can be made more or less 
 magnetic; the best temperature is about 520 C. (965 F.) and 
 after heating for 600 hours it has about two-thirds the mag- 
 netism of pure iron. The magnetism is almost completely 
 destroyed by heating for a few minutes at 750 C. (Hadfield and 
 Hopkinson, /. /. & S. /., 1914, I). It is largely employed for 
 railway crossings or rails subject to heavy wear, and is par- 
 ticularly valuable for safes, as it cannot be softened by any known 
 treatment. Recently it has had quite extensive use for light 
 armor. 
 
 Silicon steels, according to Guillet, should not contain more 
 than 5% of silicon, as above this they are apt to be brittle. 
 While the cutting capacity of a tool is increased to a certain 
 extent, this is obtained without the other advantages result- 
 ing from the use of other elements. With about 1.5 to 2% 
 silicon and low carbon and manganese a grade has been ob- 
 tained especially suitable for transformer sheets and similar 
 electrical purposes owing to the low magnetic hysteresis and 
 high permeability. With about the same silicon but about 0.45 
 to 0.65% carbon and 0.5 to 0.8% manganese (silico-manganese 
 steel) it has found considerable application for springs. With 
 less than 0.5 % silicon it is not generally corfsidered as a special 
 steel. 
 
 Vanadium steels may be roughly divided into two classes: 
 those used for general purposes, such as automobile and similar 
 parts (including springs), where the vanadium content varies 
 from about o.i to 0.25%; and special tool steel where the con- 
 tent will commonly be about 0.5 to i %. Vanadium raises 
 both the tensile strength and the elastic limit, the latter more 
 than the former. It confers the valuable property of making 
 the metal very resistant to repeated stresses, and on this ac- 
 count such steel is sometimes termed anti-fatigue steel. Aside 
 from the direct benefit, there is an indirect effect due to the 
 removal of oxygen (either as oxide or gas), and probably also 
 of the nitrogen, with which part of the vanadium combimes 
 and passes off into the slag. 
 
SPECIAL TOOL STEEL SPECIFICATIONS 453 
 
 Titanium steels (or more properly titanium-treated steels) 
 are those to which a small amount of titanium (usually as ferro- 
 titanium) has been added just before pouring. 
 
 The following steels have not so far achieved any commercial 
 prominence : 
 
 Aluminum steels, according to Guillet, when containing 
 less than 3 % of aluminum, do not differ sensibly in their proper- 
 ties from ordinary steels; above this percentage the elongation 
 is considerably reduced and the brittleness increased. 
 
 Boron steels, according to the same authority, have no com- 
 mercial application in the natural state, but might prove use- 
 ful after quenching. In that condition they have high tensile 
 strength and elasticity and are no more brittle than other 
 special steels at present in use. The most interesting results 
 were obtained with a steel containing 0.5% of boron. 
 
 Cobalt steels, containing up to 30% of cobalt, have been 
 examined by Guillet. The only item of commercial interest 
 he noted was that they did not resemble nickel steels, although, 
 from the fact that nickel and cobalt have very similar proper- 
 ties, this would have been expected. 
 
 Copper steels, according to Breuil, containing above 4% 
 of copper, are incapable of being rolled, but with a smaller 
 percentage the strength and toughness are increased, some- 
 what as with nickel. (See also Protection, page 371.) 
 
 Platinum steels, containing small percentages of platinum, 
 have been stated to be malleable and easily worked, but very 
 hard. 
 
 Tin steels, with up to about 10% of tin, have been experi- 
 mented upon by Guillet, but the material could not be forged 
 except with very small percentages; in certain respects they 
 somewhat resembled silicon steels. 
 
 Uranium steels have recently been manufactured to a certain 
 extent. It is claimed that a small addition (0.2 to 0.3 %) largely 
 replaced tungsten in tool steels, but definite information is not 
 available. 
 
 Special Tool Steel. See page 445. 
 
 Specific Gravity. See Density. 
 
 Specific Heat See page 201. 
 
 Specific Heat Pyrometer. See page 207. 
 
 Specific Line of Deformation. See page 126. 
 
 Specific Path of Deformation. See page 283. 
 
 Specific Tenacity. See page 336. . 
 
 Specific Work of Rupture. See page 481. 
 
 Specifications. Specifications for the purchase of iron and steel 
 products are primarily an explanation or description chemical, 
 physical and mechanical of the material desired for a given 
 purpose or service, and provisions for tests and inspection to 
 afford the purchaser reasonable assurance that he is obtaining 
 the properties stipulated. Requirements for marking for 
 test and service identification and permissible variations from 
 ordered dimensions and weights are generally included, and 
 sometimes definitions of terms and directions for packing and 
 
454 SPECIFICATIONS 
 
 shipping. For special materials certain manufacturing limita- 
 tions may be specified, e.g., a minimum amount of discard from 
 ingots, a maximum amount of chipping on billets, the control of 
 rolling temperatures, and directions for conducting heat treating 
 operations. 
 
 Although the commercial manufacture of iron and steel is 
 based on scientific principles, the results secured cannot be 
 predicted with mathematical accuracy owing to the practical 
 limitations of mill operations. It is, therefore, essential in 
 writing specifications to have some knowledge of manufacturing 
 processes, including the methods and possibilities of heat treat- 
 ment, and a wide experience in testing the particular material 
 which the specifications are to cover. 
 
 Specifications should be based on the indications offered by a 
 sufficient number of representative cases; experience being neces- 
 sary to avoid employing extremes, simple averages or figures of 
 an unusual or irregular nature. Unfortunately it is not always 
 possible to develop tests which will indicate the suitability of the 
 material for a given service. The tests specified should furnish 
 definite information as far as possible and those of an indefinite 
 or irrelevant character should be disregarded not only as being 
 of no value, but also likely to interfere with the production or 
 employment of suitable material. Requirements should not be 
 drawn rigidly simply to guard against incompetent or insufficient 
 inspection, and it is unjust to make the requirements for material 
 severe on the plea that they are necessary to cover irregularities 
 in material and service conditions and to provide a sufficient 
 factor of safety perhaps more accurately "factor of ignorance" 
 but more probably on account of lack of the necessary engineer- 
 ing data. Proper design has quite as much and often more to 
 do with the serviceability of an object than the quality of the 
 material from which it is made. 
 
 In the United States there are a number of technical societies 
 that issue specifications for iron and steel products. These 
 include the Association of American Steel Manufacturers, 
 American Railway Engineering Association, Master Car Builders 
 Association, American Railway Master Mechanics Association, 
 American Electric Railway Engineering Association, Society 
 of Automotive Engineers, and American Society of Mechanical 
 Engineers, but the Standards of the American Society for 
 Testing Materials are fast becoming the national commercial 
 specifications. The term "commercial" is used here in its 
 broadest sense because the American Society for Testing 
 Materials specifications are due to the joint work of the con- 
 suming and the producing interests to which is added the inter- 
 mediate experience of independent or consulting engineers. 
 As a result of an extensive system of committees, recent develop- 
 ments will always be found in the specifications contained in 
 the Book of Standards (triennial) and the reports of committees 
 in the Proceedings (annual). There are now (1918) 41 specifica- 
 tions for steel, 5 for wrought iron, and 6 for cast iron products 
 including pig iron. 
 
SPECIFICATIONS 
 
 455 
 
 In referring to different kinds of steels for various purposes, 
 the following distinctions should be made: Any divisions of 
 products by size or designations of service to be covered by the 
 term class ; the term type to designate kinds of steel, that is, 
 whether plain carbon or the various divisions of alloy steels; 
 and the term grade to designate the divisions of any type by 
 carbon content or physical properties. As the various grades 
 overlap and as some have chemical limits only while others 
 have physical limits, a table or chart showing chemical and 
 physical requirements, with the allowable variations, for the 
 different classes of iron and steel products, would be intricate 
 and cumbersome. Furthermore, the terms low carbon, medium 
 carbon, and high carbon, or soft (or mild), medium and hard 
 must be considered in connection with the context; thus a hard 
 structural steel of, say, 0.35 carbon, is much lower in this element 
 than a soft spring steel with 0.70%. The safest and best 
 method to follow is to furnish specific details and not trust to 
 indefinite and ambiguous generalities. 
 
 The following table will give an approximate idea of the ordi- 
 nary designations of carbon steels now in use : 
 
 Approximate 
 Carbon Range Common Uses 
 
 o . 08-0 . 1 8 Pipe, chain and other welding pur- 
 poses; casehardening purposes; 
 rivets; pressing and stamping 
 purposes. 
 
 o. 15-0. 25 Structural plates, shapes and bars 
 for bridges, buildings, cars, loco- 
 motives; boiler (flange) steel; 
 drop forgings; bolts. 
 Structural purposes (ships) ; shaft- 
 ing; automobile parts; drop forg- 
 ings. 
 
 o . 35-0 . 60 Locomotive and similar large forg- 
 ings; car axles; rails.. 
 
 0.60-0.85 Wrought steel wheels for steam 
 and electric railway service; loco- 
 motive tires; rails; tools, such as 
 sledges, hammers, pick points, 
 crowbars, etc. 
 
 o . 85-1 . 05 Automobile and other vehicle 
 springs; tools, such as hot and 
 cold chisels, rock drills and shear 
 blades. 
 
 0.90-1.15 Railway springs; general machine 
 shop tools. 
 
 Since about 1905 the term structural steel has been assigned 
 to a definite grade of about 0.15 to 0.25 carbon or 55,000 to 70,000 
 pounds per sq. in. in tensile strength. Previously the following 
 divisions were in common use: 
 
 Grades 
 Extra soft 
 (dead soft) 
 
 Structural (soft 
 medium) 
 
 Medium 0.20-0.35 
 
 Medium hard. . 
 Hard 
 
 Spring... 
 
 Spring 
 
456 SPECIMEN SPITTING . 
 
 Tensile Strength 
 Grade Carbon Per cent. Pounds per square inch 
 
 Soft Bessemer 0.08 to o. 10 1 55,000 to 65,000 
 
 Soft Open Hearth 0.15 to o . 22 / 
 
 Medium Open Hearth. . o. 1 8 to 0.30 60,000 to 75,000 
 Hard Open Hearth over o . 30 over 70,000 
 
 Specimens for Metallographic Examination. Preparation of: see 
 
 page ooo. 
 
 Specimen Tests. See page 467. 
 Spectral Pyrometer. See page 208. 
 Spectroscope. See page 82. 
 Spectrum Analysis. See page 82. 
 Specular Iron Ore. See page 243. 
 Specular Pig Iron (obs.). See page 355. 
 Speed of Testing. See page 475. 
 Speed of Transformation. See page 265. 
 Spell. (i) To work intermittently on a job on account of the 
 
 severity of the labor, there being usually two gangs or shifts 
 
 for each turn; (2) one such period of work. 
 Spellerizing. See page 369. 
 Spelter. Crude zinc before refining, commonly used in galvanizing. 
 
 Hard spelter is the name given to the zinc recovered by melting 
 
 the dross removed from the bottom of the galvanizing bath; 
 
 it contains about 10% of iron. 
 Spent Acid. See Pickling. 
 Spent Bone. See page 68. 
 Spent Ore. See page 258. 
 Sperry Ore. See page 244. 
 Sphaerosiderite. See page 244. 
 Spheroidizing. See page 274. 
 Spheroidizing Graphite. See page 38. 
 Spherolitic (rare). Round in shape like a sphere. 
 Spherule. See page 292. 
 
 Spherulite; Spherulitic Structure. See page 125. 
 Spicule. See page 123. 
 Spiegel; Spiegeleisen. See page 355. 
 Spiegel Recarburized. Recarburized with spiegeleisen, e.g., in 
 
 the case of Bessemer rail steel. 
 Spielfield Process. See page 380. 
 Spike. Of structure; see page 128. 
 Spike Indicator. See page 210. 
 Spill, Spilly. See Pit. 
 Spin Up. Of crucibles; see page 112. 
 Spindle. See page 403. 
 Spindle Temper. See Temper. 
 Spiral Pyrometer, Fery. See page 207. 
 Spiral Seam. See Seam. 
 
 Spirally Riveted Pipe; Welded Pipe. See page 489. 
 Spirit Thermometer. See page 205. 
 Spitting. The ejection of small particles of molten metal or slag, 
 
SPLAYED STABLE EQUILIBRIUM 457 
 
 usually when somewhat thick or pasty, by gas which has formed 
 
 underneath. 
 Splayed. Of the shape of the groove in a swage, etc., having a 
 
 greater angle or curvature than the finished section of the object 
 
 for which it is used. 
 Splendent Fracture. See page 178. 
 Splint Coal. See Coal. 
 Splintery Fracture. See page 178. 
 Split. (i) Generally of the end of a rolled piece when the end 
 
 opens up, due to a pipe or to the metal being red-short; (2) in 
 
 casehardening: see page 68. 
 Split Weld. See page 502. 
 Sponge. Metal in a porous form, generally obtained by reduction 
 
 without fusion (Raymond). 
 Sponge Bloom. See page 138. 
 Sponge-like Decay. See page 106. 
 Sponge-making Processes. See page 134. 
 Sponginess; Spongy. See page 55. 
 Spontaneous Absorption of Heat. See page 199. 
 Spontaneous Annealing. See page 334. 
 Spontaneous Combustion. See page 202. 
 Spontaneous Cracking. See pages 99 and 332. 
 Spontaneous Crystallization. See page 269. 
 Spontaneous Evolution (Liberation). Of heat: see page 199. 
 Spoon. An instrument for taking samples of metal while molten, 
 
 consisting of an iron cup or dish attached to a rod; also called 
 
 sample spoon or test spoon. 
 Sporadosiderite. See page 291. 
 Spot Chipping. See Chipping. 
 Spot Welding. See page 504. 
 Spotted Iron. See page 342. 
 Spout.^ The trough which conducts the molten metal, etc., from a 
 
 furnace; in a blast furnace this is usually called the runner. 
 Spouting. The pipe or material for spouts. 
 Spread. In rolling; see page 408. 
 Spreader. A tool for spreading refractory material (fettling) 
 
 over a furnace bottom. 
 Spreader Tuyere. See page 32. 
 
 Spreading and Turning (Eng.). In rolling: see page 414. 
 Sprig; Sprigging. See page 300. 
 Spring Heat. See page 71. 
 Sprue. (i) Of castings, runner scrap; see page 300: (2) a projection 
 
 left on a casting to be broken off and used for testing purposes 
 
 (rare). 
 
 Sprue Heat. See page 257. 
 Sprung. See page 56. . 
 Spy. See page 70. 
 Squeezer. (i) In puddling: see page 377; (2) in molding: see 
 
 page 301. 
 
 Squeezer Board. See page 301. 
 Stable Diagram. See page 271. 
 Stable Equilibrium. See page 326. 
 
458 STACK STEAM HAMMER 
 
 Stack. (i) A blast furnace; (2) a large high chimney. 
 
 Staff. See page 79. 
 
 Stage. In comparison with phase: see page 326. 
 
 Stainless Steel. See pages 367 and 451. 
 
 Stall. Seepage 181. 
 
 Stamps. See page 79. 
 
 Stamping. See Marking. 
 
 Stampings. See page 378. 
 
 Stand -By (Eng.). A spare, as an extra part for replacement. 
 
 Stand. Of rolls: see page 406. 
 
 Standards. Of a rolling mill; see page 403. 
 
 Standard Bessemer Pig. See page 344. 
 
 Standard Coil. See Coil. 
 
 Standard Ferro -Manganese. See page 352. 
 
 Standard Foundry and Furnace Coke. See page 96. 
 
 Standard Roasted Dolomite. See page 399. 
 
 Standard Solution. See page 83. 
 
 Standard Test Piece. See page 473. 
 
 Standard Wire Gage. See page 188. 
 
 Standardization. Of a testing machine: see page 469. 
 
 Stanton Test (i) Impact test: see page 482; (2) wear test: see 
 
 page 480. 
 
 Star Fracture. See page 178. 
 Star-like Crystallite. See page 122. 
 Stare. Of a fracture: see page 115. 
 Stassano Furnace. See page 163. 
 State, Changes of. See page 81. 
 State Diagram. See page 271. 
 State of Ease. See page 332. 
 Static Hardness. See page 331. 
 
 Static Indentation. To determine hardness: see page 477. 
 Static Load. See page 333. 
 Static Metamorphism. See page 122. 
 Static Strength. See page 330. 
 Static Stresses. See page 333. 
 Static Test. See page 468. 
 Stationary Bottom. See page 182. 
 Stationary Converter. See page 17. 
 Stationary Furnace. See page 312. 
 Stationary Table. See page 408. 
 Stationary Top. Of a blast furnace: see page 32. 
 Stave. (i) Pieces of wrought iron welded together as a basis for 
 
 making shafts, etc.; (2) to swell up the end of a tube. 
 Stay Tubes. In a boiler, a few of the tubes which are heavier than 
 
 the rest and have a nut screwed on the ends outside the boiler 
 
 shell to keep it from bulging outward. 
 Stead's Brittleness. See page 216. 
 Stead's Law. Of welding: see page 501. 
 Stead's Reagents. See page 287. 
 Stead Test. See page 482. 
 Steadite. See page 277. 
 Steam Hammer. See Hammer. 
 
STEAM HELVE STERLING'S CAST IRON 459 
 
 Steam Helve. See Hammer. 
 
 Steam Refinery. See page 383. 
 
 Steam Shears. See page 412. 
 
 Steaming. See Water Gas. 
 
 Steel. (i) That form of iron produced in a fluid condition, and 
 hence practically free from slag (difference from wrought iron), 
 which contains less than about 2.20% of carbon as a rule 
 less than 1.50% (difference from cast iron). It is produced 
 by the crucible, the Bessemer, and the open hearth process, 
 and also in the electric furnace. (2) The product obtained by 
 carburizing wrought iron (more rarely low carbon steel) by 
 the cementation process, and generally known as cement steel. 
 (3) Formerly steel was what could be hardened ( usefully ) by 
 quenching, while iron could not. 
 
 Steel Bronze. An alloy of about 90 % copper and 10 % tin (bronze) 
 which on account of its strength and hardness is sometimes used 
 in place of steel, particularly to resist corrosion. 
 
 Steel-cast (adj.)- Suggested to be used to indicate that a given 
 object was a steel casting, as it was claimed that it would obviate 
 any question as to whether crucible steel was meant, as would 
 be the case if "cast steel" were used indiscriminately. Crucible 
 steel should always be called "crucible steel," and the above 
 term dropped. 
 
 Steel Castings. Castings made of steel and not subsequently forged 
 or rolled. 
 
 Steel Cleaning Sand. See page 296. 
 
 Steel-faced Wrought Iron Armor Plate. See page 8. 
 
 Steel Facing. See page 166. 
 
 Steel Iron (Eng.). Pig iron intended for conversion into steel. 
 
 Steel Ladle. See Ladle. 
 
 Steel Melting-heat Processes. See page 134. 
 
 Steel Mold. See page 296. 
 
 Steel Molding Sand; Steel Sand. See page 296. 
 
 Steel Side. See page 18. 
 
 Steel -through Heat. ^See page 71. 
 
 Steel Wire Gage. See page 186. 
 
 Steel Wool. An abrasive material consisting of very fine shavings 
 of steel wire made by a special machine. 
 
 Steely Malleable. White heart malleable; see page 258. 
 
 Stefan-Boltzmann's Law. Of radiation: see page 207. 
 
 Stefan's Law. Of radiation: see page 207. 
 
 Stellar Pyrometer. See page 208. 
 
 Stellate Structure. See page 125. 
 
 Stellate Twin. See page 124. 
 
 Step. See page 282. 
 
 Stereo-Chemistry. See page 86. 
 
 Stereo-Formula. See page 86. 
 
 Stereoisomer. See page 86. 
 
 Stereoscopic Binocular Microscope. See page 285. 
 
 Stereoscopic Radiograph. See page 285. 
 
 Sterling Process. See page 118. 
 
 Sterling's Toughened Cast Iron. See Semi-Steel. 
 
460 STEWING STRAIGHTENING ROLL 
 
 Stewing. See page 376. 
 
 Sticker. (i) An ingot from which it is difficult to remove the mold 
 
 on account of sticking; (2) a pack in which the sheets stick 
 
 together: see page 430. 
 Sticking. (i) Of the charge in a blast furnace, hanging; see page 
 
 35; ^2) of an ingot which is not easily removed from the mold; 
 (3) in welding: see page 504. 
 Stiefel Process. See page 491. 
 Stiff ener. See page 406. 
 Stiffness. See page 330. 
 Stinking Coal. See Coal. 
 Stirring Rod. A rod or bar of iron or soft steel used in working an 
 
 open hearth heat. 
 Stock. (i) What is on hand ready for delivery; (2) the raw 
 
 material used for charging a furnace in the manufacture of iron 
 
 and steel; (3) the foundation for the anvil of a power hammer. 
 Stock Coke. See page 97. 
 Stock Converter Process. See page 22. 
 Stock House. A building or structure to keep under shelter 
 
 materials used in manufacturing. 
 
 Stock Indicator; Line. Of a blast furnace: see page 35. 
 Stock Pile. The pile of ore constituting the supply for a blast 
 
 furnace, particularly during the winter months. 
 Stockman Process. See page 388. 
 Stone. (i) Limestone; (2) in connection with wire: see page 95; 
 
 (3) a meteorite: see page 291. 
 Stool. See page 57. 
 Stopper. See Ladle. 
 Stopper; Stopper Down (Eng.). To close or stop up a hole, e.g., 
 
 the tapping hole of a furnace, or the hole in the top of an ingot 
 
 mold; to cap. 
 
 Stopper Head. See Ladle. 
 Stoppering (Eng.). Closing up. 
 Stopping. Material used for closing up a hole. 
 Stopping In. See page 182. 
 Stoughton Converter. See page 24. 
 Stove. See pages 27 and 34. 
 Stove Coke. See page 97. 
 Straight Open Hearth Processes. See page 310. 
 Straight Pane. See Pane. 
 
 Straightening Mangle (Eng.). Straightening rolls, q.v. 
 Straightening Press. Or gag press; a machine consisting of a 
 
 fixed straight side and a movable side, operated by a cam or 
 
 eccentric, which is brought against a bar resting against the 
 
 piece where it is bent, to straighten it. 
 Straightening Rolls. A machine comprising an upper and a 
 
 lower set of several rolls each, the rolls in the two sets being 
 
 staggered. The distance between the two sets is so regulated 
 
 for pieces of different gage that in passing through they are 
 
 made perfectly flat, i.e., straight. For plates the rolls are 
 
 plain, while for shapes they contain grooves corresponding 
 
 to the section. See also page 414. 
 
STRAIN STUBS' GAGE . 461 
 
 Strain. (i) General: see page 333; (2) effect on growth of ferrite: 
 see page 216; (3) effect on grain growth: see page 216; (4) effect 
 of time beyond elastic limit: see page 472. 
 
 Strain Gage. See page 471. 
 
 Strain Hardness. See pages 99 and 331. 
 
 Strand Rolls. See page 414. 
 
 Stranded Wire. See page 509. 
 
 Stratification. A formation consisting of layers or bands. 
 
 Stratification Foliation. See page 1 24. 
 
 Straw Temper. Oxide color: see page 230. 
 
 Straw Tinted Wire. See page 508. 
 
 Streaks. See Seam. 
 
 Stremmatograph. See page 484. 
 
 Strength. See page 330. 
 
 Strength of Materials. See page 330. 
 
 Stress. (i) General: see page 331; (2) lines of: see page 283. 
 
 Stress -Deformation Diagram. See page 471. 
 
 Stress Difference. See page 333. 
 
 Stress-Strain Diagram. See page 471. 
 
 Stress Theories. Of hardening: see pages 279 and 280. 
 
 Stretch. See page 336. 
 
 Stretch Limit. See page 471. 
 
 Strickle. See page 301. 
 
 Striction. See page 336. 
 
 Stridberg's Hearth. See page 79. 
 
 Stridsberg Process. See page 62. 
 
 Striking; Striking Up. See page 301. 
 
 Striking Energy. See page 481. 
 
 Stringing Up. Of wire: see page 508. 
 
 Strip. (i) Of ingots, to remove the mold; (2) of patterns, the taper 
 or draft: see page 296; (3) a coil: see page 95; (4) of mines 
 which are open worked, to remove the surface covering. 
 
 Strip Mill. See page 415. 
 
 Stripper; Stripping. See page 57. 
 
 Stripping Plate. (i)In molding : see page 300; (2) in a rolling mill: 
 see page 41 5. 
 
 Stroh Steel Hardening Process. See page 504. 
 
 Stromborg Process. See page 147. 
 
 Strong Contact Metal Theories. See page 282. 
 
 Strong Iron. Close-grained, gray pig iron. 
 
 Structural Composition. See page 337. 
 
 Structural Formula. (i) In chemistry: see page 86; (2) for phys- 
 ical properties: see pages 337 and 339. 
 
 Structural Properties. Formulae for: see page 337. 
 
 Structural Saturation Point. See page 273. 
 
 Structural Steel. Classification: see page 455. 
 
 Structural Tests. See page 468. 
 
 Structurally Free Cementite. See page 273. 
 
 Structurally Free Ferrite. See pages 272 and 275. 
 
 Structure. See pages 125 and 289. 
 
 Structure of Crystals. See page 121. 
 
 Strut. See page 468. 
 
 Stubs' Gage. For iron wire and steel wire: see page 188. 
 
462 STUCK OVEN SULPHUR 
 
 Stuck Oven. See page 147. 
 
 Stiickofen. See page 147. 
 
 Stud. See page 299. 
 
 Stud Gage. See page 186. 
 
 Styloid. See page 290. 
 
 Styrian Charcoal Process; Open Hearth; Raw Steel Process. 
 See page 79. 
 
 Styrian Walloon Process. See page 80. 
 
 Subaerial (rare). In air, e.g., rusting; in contradistinction to 
 subaqueous. 
 
 Subaqueous. In water. 
 
 Subcarbide Theory. Of hardening: see page 280. 
 
 Subcarburized (obs.). Applied to steel, meaning very low in 
 carbon like wrought iron. 
 
 Subcooling. In hardening: see page 279. 
 
 Subcrystalline. Non-crystalline and in unstable equilibrium. 
 
 Subcutaneous Blowhole. See page 55. 
 
 Sublimation. See page 202. 
 
 Sub-punching. See Cold Working. 
 
 Sub -transformation Range. See page 271. 
 
 Suction Producer. See Producer. 
 
 Sudden Cement. See page 67. 
 
 Sudden Fracture. See page 178. 
 
 Sudden Load. See page 333. 
 
 Sudre Process. See page 118. 
 
 Sull. Coating: see page 507. 
 
 Sullage. See page 56. 
 
 Sullage Piece. See page 56. 
 
 Sulphide Area. See page 289. 
 
 Sulphide Coating. See page 374. 
 
 Sulphide Ore. See page 245. 
 
 Sulpho-Film. See page 289. 
 
 Sulphur. S; at. wt., 32; melt, pt, 114.5 C. (238 F.); boil, pt., 
 448 C. (838 F.); sp. gr., rhombic, 2.05, prismatic, 1.98, plastic, 
 1.95. It is found both free and combined. When pure and 
 in its ordinary condition it is a pale yellow, crystalline solid. 
 It may exist in four allo tropic varieties: (i) rhombic crystals, 
 stable at ordinary temperatures; (2) prismatic needles, ob- 
 tained by allowing melted sulphur to cool slowly; unstable 
 at ordinary temperatures, and tending to pass back to the 
 rhombic variety; (3) plastic sulphur (amorphous), obtained 
 by heating sulphur until it reaches a certain viscous condition, 
 and then pouring it into water; unstable at ordinary tem- 
 peratures; (4) white amorphus sulphur, obtained by sublima- 
 tion; stable at ordinary temperatures. Sulphur combines 
 with iron to form ferrous sulphide, FeS, and ferric sulphide 
 FeS 2 (pyrites). With manganese it forms mangansee (man- 
 ganous) sulphide, MnS, which is nearly if not quite insoluble 
 in metallic iron. In ordinary steel it usually runs from about 
 0.02 to 0.10%. If combined with iron its effect is to make 
 the metal red-short, and it sometimes appears to exert a slight 
 similar effect on the metal when cold. In cast iron it makes 
 
SULPHUR ADDITIONS SURPLUS CARBIDE 463 
 
 the molten metal thick and sluggish, and appears to reduce the 
 saturation point for carbon, and to keep that present in the 
 combined state. What is termed a sulphur ball is a segregate 
 very high in sulphur which sometimes separates out from high 
 sulphur pig during solidification. For influence on corrosion 
 see page 366. 
 
 Sulphur Additions. See Recarburization. 
 
 Sulphur Ball. See Sulphur. 
 
 Sulphur Coal. See Coal. 
 
 Sulphur Print. See page 288. 
 
 Sulphuric. Sulphur in chemical combination in: its highest valence 
 VI. 
 
 Sulphurous. (i) Containing a large or excessive percentage of 
 sulphur; (2) sulphur in chemical combination in its lower valences 
 II or IV. 
 
 Summerlee Process. Same as the Neilson process, for the recovery 
 of tar and ammonia from the gas of a blast furnace using raw 
 coal. 
 
 Supercarburized. Cemented; used for Harvey process: see page 
 67. 
 
 Superficial Cementation. See page 67. 
 
 Superfusion. See page 268. 
 
 Superheated. (i) Of steel: see page 202; (2) of blast, heated in 
 modern fire-brick-stoves to above 600 F. (315 C.), which was 
 about the limit of temperature with the old cast-iron pipe stoves ; 
 (3) of steam which has been heated to above the temperature at 
 which moisture can form, and out of contact with water; dry 
 steam. 
 
 Supermolten. See page 202. 
 
 Superpxidation. Oxidation beyond what is usual, as for special 
 purification in the electric furnace process, etc. 
 
 Superposing Method. See Alloy. 
 
 Supersaturated Solution. See Solution. 
 
 Supersaturated Steel. See page 273. 
 
 Supersilicated (rare). Containing a large (or extra) percentage of 
 silica, e.g., of slag. 
 
 Supersolubility Curve. See page 269. 
 
 Surface Band. See page 127. 
 
 Surface Blowhole. See page 55. 
 
 Surface Cementation. Case hardening: see page 67. 
 
 Surface Combustion. See page 203. 
 
 Surface Deformation. See page 283. 
 
 Surface Force. See page 331. 
 
 Surface Hardening. Case hardening: see page 67. 
 
 Surface Resistance. See page 200. 
 
 Surface Resistance Furnace. See page 153. 
 
 Surface Scratching. See page 478. 
 
 Surface Traction. See page 331. 
 
 Surfusion. The abnormal or unstable condition of a body which, 
 under certain conditions, may remain liquid after the tempera- 
 ture has fallen below the freezing point: see pages 268 and 327. 
 
 Surplus Carbide. Cementite: see page 273. 
 
464 SURPLUS FERRITE SZEKELY PROCESS 
 
 Surplus Ferrite. See page 272. 
 
 Surzycki Process. See page 317. 
 
 Swab; Swab Pot See page 298. 
 
 Swab Up. In the crucible process: see page 115. 
 
 Swaff (Eng.). Swarf. 
 
 Swage Work. See Hammer. 
 
 Swan Process. See page 367. 
 
 Swarf (rare). Fine particles of metal (usually iron or steel) 
 produced in machining or grinding. 
 
 Swarfing Furnace. See page 379. 
 
 Sweating. A method of fastening two metallic surfaces together by 
 means of a very thin invisible layer of solder. 
 
 Sweating Heat. Wash heat, q.v. 
 
 Swedish Bessemer Process. See page 23. 
 
 Swedish Fixed Converter. See page 23. 
 
 Swedish Lancashire Process. See page 77. 
 
 Swedish Metallic Sponge. See page 147. 
 
 Swedish Walloon Process. See page 79.. 
 
 Sweep. (i) In structural shapes and rails, side curvature: see 
 page 49; (2) in molding: see page 300. 
 
 Sweep Molding. See page 300. 
 
 Sweeping Up. See page 301. 
 
 Swell. (i) A defect in castings: see page 58; (2) in cold rolling or 
 drawing: see Cold Working; (3) a raised portion on a piece of 
 rolled material, such as a rail, from the pressure of gas, in a gas 
 pocket located near the surface, while the metal is hot and soft. 
 
 Swill. In pickling: see pages 341 and 431. 
 
 Swording Stickers. See page 430. 
 
 Symbol. In chemistry: see page 86. 
 
 Symmetry, Law of. For crystals: see page 120. 
 
 Syndolag. See page 397. 
 
 Synthesis; Synthetic Chemistry. See page 82. 
 
 Synthetic Reaction. See page 87. 
 
 Synthetic Steel. The opposite of natural steel; sometimes applied 
 as in the case of an alloy steel to which the alloy elements are 
 specially added in amounts as desired, as opposed to natural steel 
 where the composition depends entirely or principally on the 
 composition of the ore. 
 
 Syssiderite. See page 291. 
 
 System. (i) In connection with the phase rule: see page 326; 
 (2) of crystallization: see page 120. 
 
 Systemmatic Deviation. Of slipping: see page 283. 
 
 Szekely Process. See page 65. 
 
T; t. T: absolute temperature; transverse (of tests, etc.); t: time; 
 
 thickness. 
 
 Ta. Chemical symbol for tantalum: see page 84. 
 Tb. Chemical symbol for terbium: see page 84. 
 Te. Chemical symbol for tellurium: see page 84." 
 Th. Chemical sybmol for thorium: see page 84. 
 Ti. Chemical symbol for titanium, q.v. 
 Tl. Chemical symbol for thallium: see page 84. 
 Tm. Chemical symbol for thulium : see page 84. 
 T. A. I. M. E. Transactions of the American Institute of Mining 
 
 Engineers. 
 
 T Hammer. See Hammer. 
 T.U. Thermal or heat unit. 
 Table. See page 407. 
 Taenite (Reichenbach). See page 291. 
 Tag Butt Welding. See page 489. 
 Tagger. See page 433. 
 Tail Helve. See Hammer. 
 Take the Blast. See page 35. 
 
 Take a Heat. Melting iron in a cupola for foundry work. 
 Take Off. The blast: see page 37. 
 Talbot Furnace. See page 316. 
 Talbot Process. (i) For treating ingots: see page 64; (2) open 
 
 hearth process: see page 316; (3) purification process: see page 
 
 384- 
 
 Talbot and Stirling Process. See page 118. 
 
 Tamping. (i) A molder's term which signifies the ramming up of 
 the sand around a pattern; (2) stopping the tap hole of a cupola 
 furnace with clay; the term is derived from the beating down a 
 charge into a hole in blasting and mining operations (Homer). 
 
 Tandem Continuous Mill. See page 409. 
 
 Tandem Roughing Mill. See page 416. 
 
 Tangential Stress. See page 332. 
 
 Tank Converter. See page 20. 
 
 Tank Cupola. See page 182. 
 
 Tap. Of a furnace: see page 315. 
 
 Tap Bar. See page 70. 
 
 Tap Cinder. See Slag. 
 
 Tap Hole. See page 311. 
 
 Tap Wagon (obs.) . A ladle of small size. 
 
 Taper. Of a foundry pattern; draft: see page 296. 
 
 Tappet. See page 411. 
 
 Tappings. (i) In puddling: see page 377; (2) molten metal from 
 the blast furnace (obs.); (3) of slag: see page 438. 
 30 465 
 
466 TAPPING HOLE TEMPERATURE 
 
 Tapping Hole. See pages 32 and 182. 
 
 Tapping Rod. A rod or bar used to open the tapping hole of a 
 
 furnace- 
 Tapping Slag. See Slag. 
 
 Tardy Hydrate. Of calcium chloride: see page 30. 
 
 Tarmac. See Slag. 
 
 Taussig Furnace. See page 164. 
 
 Taylor Process. See page 380. 
 
 Taylor-White Process; Steel. See page 446. 
 
 Teaming (obs.). Teeming: see page 57. 
 
 Tear. (i) Of metal which does not cut crisply, usually the fault 
 of the tool; (2) the rupture of material in drawing, due to too 
 heavy draft or to dirt or scale in the die. 
 
 Tearing Stress. See page 336. 
 
 Technical Chemistry. See page 81. 
 
 Tectotherm. See page 267. 
 
 Tedge. See page 299. 
 
 Teem; Teeming. See pages 57 and 115. 
 
 Teeming Hole. See page 115. 
 
 Telegraph. A hook or pair of tongs suspended by a rod from a 
 pulley running on an overhead beam or rail, and used for trans- 
 porting small billets, puddle balls, etc. 
 
 Temper. (i) Of crucibles: see page 112; (2) hardness, q.v. 
 
 Temper. The percentage of carbon in steel (usually crucible 
 steel) with special reference to the purpose for which it is suitable: 
 Razor temper, i>%; saw -file temper, i%%; tool temper (drill 
 temper), ij^%; spindle temper, i J%; chisel temper, i%; set 
 temper, % %; die temper, % %. Brearly (" Heat Treatement of 
 Tool Steel," page 10) gives the following figures: 
 
 Die Temper 0.70-0.75 approx. carbon 
 
 Smiths' Tool Temper o . 80-0 . 85 
 
 Shear Blade Temper o . 90 
 
 General Purposes Temper o . 90-0 . 95 
 
 Axe Temper o . 95-1 . 05 
 
 Cutlery Temper i . oo-i . 10 
 
 Tool Temper i . 20-1 . 30 
 
 Razor Temper i . 30-1 . 40 
 
 The content of carbon also may be roughly indicated by the 
 terms low temper steel, medium temper steel, and high temper 
 steel. Irish temper was a grade of cement bars formerly made 
 containing about 0.3 %. 
 
 Temper Carbon. See pages 257 and 278. 
 
 Temper Casting. See page 257. 
 
 Temper Graphite. See page 257. 
 
 Temper Test. See page 476. 
 
 Temper Tinting. See page 288. 
 
 Temperability. See page 227. 
 
 Temperature. See page 199. 
 
 Temperature Colors. See page 210. 
 
 Temperature of Combustion. See page 203. 
 
 Temperature-Density Curve. See page 225. 
 
TEMPERATURE INTERVAL TESTING 467 
 
 Temperature Interval. See page 265. 
 
 Temperature Measurement. See page 204. 
 
 Temperature Stresses. See page 333. 
 
 Tempered Casting. See page 257. 
 
 Tempering. (i) Of steel: see pages 212 and 230; (2) of molding 
 sand: see page 296. 
 
 Tempering Charge. See page 233. 
 
 Tempering Colors. See page 230. 
 
 Tempering Martensite. See page 276. 
 
 Tempering Plate. See page 231. 
 
 Tempering Temperature. See page 230. 
 
 Tenacity. See page 330. 
 
 Tender. Brittle, q.v. 
 
 Tensile Formulae; Properties. See page 337. 
 
 Tensile Resilience. See page 331. 
 
 Tensile Strain; Strength; Stress. See pages 330 and 333. 
 
 Tensile Test. See page 469. 
 
 Tension; Tensional. Tensile. 
 
 Terminal Grain Boundary. See page 283. 
 
 Ternary Alloy. See Alloy. 
 
 Ternary Compound. See page 88. 
 
 Ternary Steels. See page 443. 
 
 Terne Plate. See pages 371 and 432. 
 
 Terre-Noire Process. (i) For quenching: see page 229; (2) for 
 tempering: see page 233. 
 
 Terreault and Hilzinger Process. See page 258. 
 
 Terrestrial Iron. See page 291. 
 
 Tertiary Crystals. See page 121. 
 
 Tesseral System. Of crystallization: see page 120. 
 
 Tessular System. Of crystallization: see page 120. 
 
 Test. See Furnace Test. 
 
 Test Bar. See page 70. 
 
 Test to Destruction. See page 467. 
 
 Test Piece. Influence of form: see page 473. 
 
 Test Spoon. See Spoon. 
 
 Testing. (i) In general, any method for determining the chemical 
 or physical quality of material; (2) specifically (and as commonly 
 understood), the determination by physical means (physical 
 testing) of the suitability of a material for the purpose intended, 
 and having no direct connection with the chemical composition 
 or defects which properly belong under chemical analysis and 
 inspection respectively; (3) in connection with ordnance material, 
 the term proving (e.g., proving ground) is employed, and for 
 armor plate ballistically tested, the term attacking. 
 
 Tests may be divided into two classes: (a) destructive tests 
 (testing to destruction), where it is desired to learn the ultimate 
 properties; and (b) proof tests, where it is desired to impose on 
 material or objects, actually going into service, tests to determine 
 that they are entirely suitable. Tests are commonly made on 
 portions or samples selected to represent a given lot (specimen 
 tests), usually tested to destruction, based on the well recog- 
 nized assumption that material, or objects of such material, made 
 
468 TESTING 
 
 and treated at one time, is commercially uniform; they may 
 also be made on entire objects (full-size tests), which may also 
 be specimen tests. When made on built-up objects they are 
 sometimes referred to as structural tests. Tests may be further 
 divided, depending upon the nature of the stresses imposed, 
 into (c) static tests or slow tests, and (d) dynamic tests or 
 impact tests. 
 
 Composite structures, such as bridges, which are made up of 
 many component parts of different sizes and properties, must 
 be designed to support two kinds of loads: (a) dead loads, or 
 the weight of the structure itself, including any permanent 
 fixtures, and (6) live loads or moving loads, such as people or 
 vehicles passing over it. A uniform load is one which is evenly 
 distributed throughout the structure. A concentrated load 
 is where one portion is more severely stressed than another, 
 hence moving loads may also be referred to as moving concen- 
 trated loads. The load which the structure is designed to bear 
 is called the working load, and the corresponding strength re- 
 quired, the working strength. This must always be less than 
 the elastic resistance, and may be referred to as the permissible 
 working stress, safe range of stress or safe load. As opposed 
 to this, the ultimate strength is sometimes called the absolute 
 strength. The factor obtained by dividing the ultimate strength 
 by the total load is known as the factor of safety; French engi- 
 neers, as a rule, base this factor on the elastic limit, which 
 may be considered roughly as about one-half the ultimate 
 strength, at least in the case of ordinary structural material. 
 The proof load or proof weight is the load applied to determine 
 the value of the material tested when it is not intended that 
 observable deformation (or above a prescribed maximum 
 value) shall take place (Thurston); the strength required for 
 this is known as the proof strength, and is usually equal, or nearly 
 so, to the maximum elastic resistance of the piece. The proof 
 strain (practical proof strain) is determined by taking one-half 
 of the intensity of the stress the piece can sustain, a certain 
 maximum number of times, without injury. 
 
 By bar is understood a "piece of uniform cross section. Its 
 cross sectional area, used in computing certain values, is fre- 
 quently referred to as cross section, section area, or simply 
 section. A bar whose length is over about eight times its dia- 
 meter or thickness is called a column or strut when subjected 
 principally to longitudinal forces. If the forces act principally 
 transversely, it is a beam, when it is supported near the ends, a 
 simple beam; when it is supported at one end and near the middle, 
 the other end being unsupported, a cantilever beam; and when 
 supported at more than two points, a continuous beam. 
 
 While in some cases the specimen tests may be made on a 
 finished object or section, such as a railroad axle or a piece of 
 rail, yet ordinarily, as with plates and shapes, this cannot be 
 readily done, and hence a relatively small sample or test piece 
 is taken. Further as most testing is carried to destruction this 
 prevents a large amount of good material from being wasted 
 
TESTING 469 
 
 unnecessarily. If the length of the test piece is parallel to the 
 direction of rolling or the extension which the material has 
 undergone, it is called a longitudinal test piece; if perpendicular, 
 a transverse test piece. 
 
 Tensile Tests. Also called tension tests, pulling tests, or, 
 rarely, traction tests. These are by far the most common and 
 are carried out by making the specimen fast at one end and 
 applying a load (in the direction of its length) to the other end 
 until it has been pulled apart. For material of very small 
 cross section, such as wire, this is readily done by suspending 
 weights to it (hanging test), but with larger sections requiring a 
 great many thousand pounds to effect rupture, mechanical 
 means must be employed. A testing machine consists essen- 
 tially of clamps, grips, or shackles for holding the specimen; 
 mechanism for applying the load to the specimen; a lever (beam) 
 or other device for weighing or measuring the load; and a heavy 
 frame for holding the various parts together. The machine is 
 vertical or horizontal, depending upon the respective position 
 in which the specimen is held. The power is usually furnished 
 by an electric motor (the variable speed type is coming largely 
 into use) or in some cases, particularly for very large machines 
 of a million or more pounds capacity, it may be hydraulic. With 
 the common type of machines it is measured in the same manner 
 as with an ordinary scales by a jockey weight or rider which is 
 run out along the graduated beam to keep it balanced; in the 
 case of some hydraulic machines, such as used for testing eye 
 bars, this may take the form of a mercury column which rises in 
 a graduated tube. While the load is below the elastic limit, the 
 rider must be moved forward at a uniform rate of speed, but when 
 it is just exceeded the beam drops (drop of the beam, fall of the 
 beam), and the corresponding reading is ordinarily taken to 
 represent the elastic limit or more properly the yield point. 
 Testing machines must be checked or calibrated at intervals 
 to assure their accuracy. Inaccuracies may be due to worn or 
 broken knife edges or to dirt or grease interfering with the 
 sensitiveness, or to the beam or other part becoming bent or 
 distorted. Calibration may consist in loading the platen with 
 standard weights, or more frequently, to secure a greater range, 
 an arrangement of levers is provided which multiplies (usually 
 twenty or twenty-five times) the force exerted by the known 
 load. The corresponding reading of the machine will indicate 
 its degree of accuracy. Standardization is a term sometimes 
 employed to designate the relative accuracy with another 
 machine as determined by the comparative results of testing a 
 number of similar pieces on each. 
 
 The term elastic limit is of such variable meaning that it is well 
 to consider briefly its various synonyms and applications. T. D 
 Lynch ("Elastic Limit," Proc. A. S. T. M., 1915) makes the 
 following observation: 
 
 "We are accustomed to hear the free use of the following ten 
 distinct terms, namely, (i) proportional limit, (2) elastic limit, 
 (3) permanent set, (4) true elastic limit, (5) apparent elastic 
 
470 TESTING 
 
 limit, (6) commercial elastic limit, (7) elastic limit by extenso- 
 meter, (8) elastic limit by drop of beam, (9) elastic limit by the 
 dividers, (10) yield point. 
 
 "The first term, proportional limit, is very generally under- 
 stood to be at point P on the curve (Fig. 60), and the tenth 
 term, yield point, at the point Y, whereas the other eight designa- 
 tions are located on the curve more or less indefinitely between the 
 points P and F, depending upon the interpretation peculiar to 
 different engineers." 
 
 (It will be noted that in the following additional terms are 
 described.) 
 
 The following definitions have been adopted by the A. S. T. M. : 
 
 "Elastic limit is the greatest load per unit of original cross 
 section which does not produce a permanent set. (This determi- 
 nation is rarely made in the commercial testing of materials.) 
 
 "Proportional limit is the load per unit of original cross section 
 at which the deformation ceases to be directly proportional to the 
 load. (This determination is rarely made in the commercial test- 
 ing of materials.) 
 
 "Yield point is the load per unit of original cross section at 
 which a marked increase in the deformation occurs without 
 increase of load. It is usual.y determined by the drop of the 
 beam of the testing machine or by the use of dividers." 
 
 Permanent set and true elastic limit are covered by the definition 
 above for elastic limit. The apparent elastic limit as defined by a 
 French commission was "the load per square mm. of the original 
 section where the deformation begins to increase sensibly with 
 no increase in the external force applied." It will be noted that 
 this agrees with the A. S. T. M. definition for yield point. John- 
 son proposed to extend its meaning in accordance with the 
 following definition: "The apparent elastic limit is the point on 
 the stress diagram of any material in any kind of test, at which the 
 ' rate of deformation is 50% greater than it is at the origin." 
 This is commonly known as the Johnson elastic limit, and its 
 method of computing is shown in Fig. 61. Johnson at first 
 proposed for this the term relative elastic limit. 
 
 The Scoble-Johnson apparent elastic limit or Scoble's yield 
 point is much the same and is determined (by a tangent method) 
 by the point of intersection of those portions of the curve which 
 represent respectively a state of perfect elasticity and of flow. 
 
 Commercial elastic limit is a term loosely used in the same 
 sense as yield point. Elastic limit by extensometer, as its 
 name indicates, requires the use of an instrument for determining 
 the rate of stretch. It may actually correspond with the true 
 elastic limit but more often signifies something approximating 
 the proportional limit. Elastic limit by drop of the beam is 
 calculated from the reading on the beam when it drops. The 
 elastic limit by dividers in its ordinary sense is determined by 
 fitting the points of a pair of dividers in the gage marks on the 
 specimen, and taking the reading when one of the points no 
 longer rests in its respective mark. A special method known as 
 the scribe or scriber method is carried out as follows: With the 
 
TESTING 
 
 471 
 
 dividers set at the gaged length, and with one of the points resting 
 in the punch mark, a fine scratch is made on the specimen with 
 the other; after applying and removing the load corresponding 
 to the specified elastic limit, a line is again scribed. If only one 
 line is visible the material is recorded as having exceeded the 
 requirement, if a difference of about 0.005" (f r a 2 " gaged 
 length) is noted, the actual figure is recorded; with any greater 
 difference or yield the test is considered to have failed. Primitive 
 elastic limit is used by Rosenhain to indicate that the results 
 with a material as originally tested may be altered if repeated 
 after subsequent treatment. Stretch limit has been used in the 
 same sense as yield point. The Engineering Standards Com- 
 mittee (British) states that "a steel test piece at the yield point 
 takes rapidly a large increase of extension amounting to more 
 than 3-^po of the gage length." This is sometimes referred to as 
 the British or English yield point. The yield stress corresponds 
 to the state for which the stress-strain curve becomes parallel to 
 
 Strain 
 
 O Elongation 
 
 FIG. 60. Stress-deformation diagram of a tension test. 
 (Lynch, Proc A. S. T. M., 1915.) 
 
 the axis of strain. At the yield point the amount of strain 
 depends to a certain extent on the length of time during which the 
 load acts (Smith and Wedgwood). 
 
 An extensometer is an instrument for showing the amount 
 (or rate) of stretch which the specimen undergoes during tensile 
 test. In one form commonly employed it is called a strain gage. 
 A recording extensometer or autographic recorder is an instru- 
 ment arranged to draw a curve automatically. A stress-strain 
 or stress -deformation diagram is a cruve plotted with its co- 
 ordinates as stress (load) and strain (deformation) respectively. 
 When the elastic limit has been passed the rate of stretch is 
 fairly uniform with increase in load until necking occurs, at 
 which point the maximum load is registered on the beam (or 
 otherwise), and it is then necessary to run the rider back a 
 short distance if it is desired to register the load (breaking load) 
 
472. 
 
 TESTING 
 
 at the moment of rupture; this term is frequently used improperly 
 for maximum load. Tonnage (Eng.) is sometimes used for 
 tensile strength (measured in gross tons per square inch). In 
 a specimen being tested, continued extension from continued 
 application of the same load, the time being an important factor, 
 
 40,000 
 30,000 
 20,000 
 10,000 
 
 D 
 
 ' 
 
 i M 
 
 F 1 
 
 / c l 
 
 G/ 
 
 ^ 
 
 
 
 Steelll 
 fl 
 
 i 
 
 .^^ 
 
 
 1 
 
 /^ 
 
 
 
 Legend 
 
 20 403 - 
 
 
 Fr 
 l i 
 
 If 
 
 E 
 
 Tensile 
 Yield I 
 Apparc 
 
 Strength 
 olnt, lb.j 
 nt Elasti 
 
 lb.per sq 
 ler sq.ln. 
 Limit,! 
 
 
 . 73,100 
 . 37,650 
 18,000 - 
 
 
 
 ).per sq.in.. . . . 
 
 ill 
 I'A 
 
 
 
 
 
 3 0.1 0.2 0.3 0.4 0.5 0.6 
 Elongation in 2 in., percent 
 
 ethod of treating apparent elastic 
 
 0.7 0.8 0.9 
 
 limit. (Lynch 
 
 Proc. A. S. T. M., 1915.) 
 
 is called creeping or plastic elongation; as it is particularly 
 noticeable after the elastic limit has been passed. It is also 
 referred to as strain beyond the elastic limit. The reduction of 
 area is the difference between the reduced area at the point of 
 rupture (smallest section) and the original, and is practically 
 
 Note : The Gage Length, Parallel Portions and Fillets shall be as shown, 
 but the Ends may be of any Form which will Fit the Holders of 
 the Testing Machine. 
 
 FIG. 62. A. S. T. M. standard 2" turned test piece. 
 
 always expressed as a percentage; it is nearly independent of the 
 gaged length. It may be expressed by the formula 
 
 X ioo 
 
TESTING 473 
 
 Where R reduction of area percent; 
 
 a = original cross-sectional area; 
 a' = reduced cross-sectional area. 
 
 The test pieces are either round or rectangular in cross section. 
 They may be cut from material as rolled, such as bars, in which 
 case they are of sufficient length to provide space at the ends for 
 gripping. For particular work, or if the material is incon- 
 veniently large, as in the case of forgings or other heavy objects, 
 they are machined down to provide a middle portion of parallel 
 section connected by fillets with collars or enlarged ends for 
 holding in the machine. Upon the parallel section is laid off the 
 length (gage length, gaged length) in which the elongation is to 
 be measured, usually indicated by prick-punch marks (pop marks, 
 datum points). In this country, for plates or similar flat material 
 permitting of having two of the surfaces rolled, the specimen is 
 usually rectangular (the other sides being machined or milled), 
 with]a gage length of 8", the thickness being that of the 
 
 About 3" J , * Ljg 
 
 v .f ! Not less than 
 
 -About 18 - 
 
 FIG. 63. A. S. T. M. Standard 8" flat test piece. 
 
 given material; for turned specimens, cut from large pieces, the 
 gage length is commonly 2", with diameter of %". The standard 
 test pieces of the American Society for Testing Materials are 
 shown in Figs. 62 and 63. The effect of form of the test piece 
 must be taken into consideration, particularly as regards the 
 elongation. It has been found approximately true that the same 
 results will be secured by two test pieces if they are of identical 
 dimensions or of similar form; this is known as Barba's law or the 
 law of proportionality, or similarity. This is given by the formula 
 
 Where P is the proportionality; / is the gaged length; and a is the 
 cross-sectional area. The values of P in various standard test 
 pieces are given in the following table: 
 
474 
 
 TESTING 
 
 Comparative Requirements for Elongation for Different 
 
 Test Speicmens 
 
 Name Formula Size Comparative 
 
 elongation, 
 
 u. s.. 
 
 M 
 
 t 
 
 French . . . 
 
 a 
 
 i 
 
 = 66.67 
 = 8,) 
 
 2" 
 
 (20) 
 
 (18) 
 
 Italian . . 
 
 German . . 
 
 100 mm. X 13 . 8 mm. 
 
 3.94" Xo.543"0 (12) 
 
 5"Xo. 5 " 
 
 loomm. X 10 mm. </> (10) 
 
 n-3 
 
 3.94" X 0.349" 
 100 mm. X 10 mm. 
 
 (10) 
 
 3.94" X 0.394"^ 
 
 / = gage length 
 
 a = cross-sectional area 
 
 D = diameter. 
 
 NOTE. Figures in parenthesis ( ) are estimated. 
 
 Owing to the effect of necking with local increase in the elonga- 
 tion, it is customary to eliminate specimens which have not 
 broken within the middle third of the gage length; Martens has 
 shown that in some cases the elonagtion for specimens breaking 
 near one end, as compared with those breaking in the middle, has 
 been lowered as much as 20%. It is pointed out by Martens 
 (Resistance of Materials, Henning's trans., pp. 121-2) that elonga- 
 tion really consists of two parts: (a) the extension (nearly 
 uniform) before local contraction or necking occurs, and (b) the 
 local elongation due to such necking. He gives the following 
 formula for determining the elongation for any gage length in the 
 case of material of known properties: 
 
 e% = 100 
 
 Where e = elongation, = extension of unit length up to the 
 moment of local contraction, e c extension during local con- 
 traction, l a = gage length. This is of course not practicable for 
 ordinary work, and a direct determination is the only accurate 
 method for obvious reasons. Prof. Unwin also showed by ex- 
 periment for turned test pieces, that if the value obtained by 
 dividing the gaged length by the diameter was constant, the 
 
TESTING 
 
 475 
 
 elongation would be approximately constant. In the case of 
 material like steel, the necking down has a material effect on the 
 elongation; consequently, the difference in gaged length is more 
 noticeable with pronounced local necking which occurs in the 
 softer grades and especially in heat treated and alloy steels. 
 With rectangular specimens, up to a certain point, the greater 
 the ratio of width to thickness the higher the elongation. As 
 regards other tensile properties, the strength, elastic limit, and 
 reduction of area are not so greatly affected. The strength and 
 elastic limit are increased by a sudden change of section, particu- 
 larly where the specimen is short, such as a collar or shoulder 
 without fillets or where a notch is cut in the piece. For a com- 
 plete discussion treatises, such as those by Martens or Unwin, 
 must be consulted. 
 
 The speed of testing, i.e., the rate at which the machine is 
 operated, principally affects the determination of the yield 
 point. The speeds recommended by the A. S. T. M. are as 
 follows : 
 
 
 
 Maximum Crosshead Speed for 
 
 
 
 Testing Machine in 
 
 Specified Minimum Ten- 
 sile Strength of Material 
 
 Gage 
 Length 
 
 Determining 
 
 
 
 
 
 Yield Point 
 
 Tensile 
 Strength 
 
 Lb. sq. in. 
 
 In. 
 
 In. per min. 
 
 In. per min. 
 
 80,000 or 
 
 8 
 
 0.50 
 
 2.O 
 
 under 
 
 2 
 
 2.00 
 
 6.0 
 
 Over 80,000 
 
 8 
 
 0.25 
 
 I.O 
 
 
 2 
 
 0.50 
 
 2.0 
 
 After rupture the reduced dimensions, at the point of rupture, 
 are measured for the purpose of determining the reduction of 
 area; the two portions are then fitted accurately together and, 
 from the increase in distance between the punch marks, the 
 elongation, either actual or as a percentage, is calculated. 
 
 It is a well recognized fact that, for material of the same grade 
 and treatment, as the strength increases the ductility decreases 
 and vice versa. This is sometimes covered in specifications by 
 the proportion or inverse ratio (which is approximately correct 
 within certain limits) between them. Requirements according 
 to this would be stated, for example, elongation, not less than 
 
 1,500,000 
 
 ; and reduction of area, not less than 
 
 2,400,000 
 
 A device, known as' a weigh bar, is sometimes employed where 
 a completely equipped testing machine is not available. This is 
 simply a bar of high elastic limit and large section which is cali- 
 brated as to extension (within its elastic limit) for different 
 
476 TESTING 
 
 weighed loads. The specimen to be tested is attached to one 
 end and the free end of each attached to any machine capable 
 of exerting tension. By measuring the extension on the weigh 
 bar during the test a simple calculation will indicate the actual 
 load applied. 
 
 Tensile properties may also be determined approximately 
 by Brinell's ball-testing method (see below). 
 
 Compression tests may usually be made on the same type 
 of vertical machine as used in tensile tests. As explained in 
 Physical Properties the elastic limit is the true measure of 
 strength of a ductile body owing to the flowing, with consequent 
 increase of section, which results when this limit is exceeded. 
 It is checked by a measuring device termed a compressometer 
 similar to an extensometer. A piezometer is an 'instrument to 
 determine directly the modulus of compression. Compression 
 tests are also used to determine ductility in which case they con- 
 sist in reducing a piece (either hot or cold) a certain proportion 
 of its original height. 
 
 Hammer tests, or forging tests, are used to determine the 
 malleability of metal; the sample is hammered (hot or cold) 
 usually to a given fraction of the original thickness. In making 
 a scarfing test one edge of a flat piece is hammered down at 
 an angle, and no cracks must result. Smithy tests (Eng.) 
 usually consist in heating a piece, splitting it a certain distance, 
 and bending the ends outward into a ramshorn (ramshorn 
 test); a hole may also be punched near the cut and drifted. 
 
 Bend (bending) tests are static tests to determine the ductility, 
 and to a certain extent the toughness, of material, by bending a 
 specimen over on itself, usually 180 but in some cases 90, in the 
 former case flat (for small and soft material) or in either case 
 with a given curvature at the bent portion, frequently expressed 
 as around a bar of stated diameter, D, or as a function of the 
 thickness, t, of the piece, as 180 D = $t. The specimen is 
 required to meet this test without evidence of cracking on the 
 outside of the bent portion (where the strain is greatest) ; in some 
 cases, particularly relatively brittle or high elastic material such 
 as springs, the test may be carried on until rupture occurs when 
 the angle is measured by some form of protractor. A nick bend 
 test is where a nick or notch is cut transversely in the specimen, 
 usually on the outside of where the bend is to occur, sometimes on 
 both sides or all around. This is used practically only in connec- 
 tion with fire box steel, when it is frequently referred to as 
 homogeneity test. Bends may be of the following kinds: 
 
 1. Cold bend: specimen as manufactured with no subse- 
 quent treatment except shearing or machining. 
 
 2. Hot bend: Specimen heated to a cherry red, and tested 
 at that temperature. 
 
 3. Quench bend (rarely called temper test): specimen heated 
 to a cherry red and quenched in water before bending. 
 
 A test for the toughness and elasticity of wire, sometimes 
 called snarling, consists in bending and twisting it backward 
 and forward. 
 
TESTING 477 
 
 Transverse tests or deflection tests are usually employed in 
 determining the elastic limit (and the transverse strength if the 
 material breaks before bending too far) for such objects as leaf 
 springs, carriage axles, etc. It consists in supporting the piece 
 on bearings spaced a certain distance apart and applying the load 
 at the middle; the stresses with corresponding strains (deflec- 
 tions) are then plotted, including any permanent set after each 
 successive load has been applied and removed. A somewhat 
 similar test, known as a dead weight test or loading test, is 
 occasionally applied (e.g.] to rails; a full-size specimen is laid on 
 supports a stated distance apart and has to sustain a given load 
 a certain length of time without any permanent deflection after 
 the load has been removed. "The modulus of rupture has a 
 conventional meaning. It expresses in pounds per square inch 
 the apparent maximum fiber stress, tension or compression, of a 
 member transversely loaded, as it is just on the point of breaking ; 
 the stress being calculated by the common beam theory, with its 
 three important assumptions which are known to be inaccurate 
 above the elastic limit" (L. H. Fry). 
 
 Shearing tests consist in determining the stress required to 
 shear or cut material, such as plates or bars; in some cases by 
 applying shearing stresses to the rivets in riveted pieces. It is 
 expressed per unit of area. Punching tests are another form of 
 shearing tests, and usually consist in punching holes in a sample 
 to determine the suitability of the material for this kind of work. 
 It is rarely required to determine the actual resistance per unit 
 of area. In connection with this a drift test is sometimes speci- 
 fied. This is performed by enlarging a punched hole a certain 
 amount, without causing any cracks, by driving through it a 
 tapered pin. A torsion test also involves shear. It consists 
 in twisting the specimen, the actual load and the number of 
 circular degrees being measured for the elastic limit and the 
 ultimate strength respectively. The elastic limit may be checked 
 by a torsiometer similar to an extensometer. The stress is a 
 function of the cube of the diameter or thickness. In general 
 results torsion tests agree closely with tensile tests although the 
 actual respective figures may not be directly comparable except 
 for standard test specimens. 
 
 For the latest information on detailed requirements and stand- 
 ard specifications the Proceedings and Year Book of the Ameri- 
 can Society for Testing Materials should be consulted. 
 
 Hardness Tests. Static indentation or pressing-in method. 
 Brinell's ball-testing method consists in measuring the indenta- 
 tion produced by forcing into the material a hardened steel ball 
 of a definite size (usually 10 mm. in diameter) under a standard 
 load (usually 500 Kg. for soft materials such as brass, and 3000 
 Kg. for hard materials such as steel). From the size of the 
 impression the hardness number, H, can be calculated according 
 to Brinell's formula : 
 
 irD (D \D* d*) 
 
478 TESTING 
 
 " W = load in Kg.; D = diameter of ball in mm.; d = diameter of 
 impression in mm. Benedick's formula, for the same purpose is 
 as follows: 
 
 L load in Kg. ; A superficial area of concave surface of indenta- 
 tion; p = radius of ball. In the table given below are the approxi- 
 mate relations between hardness number and tensile strength. 
 Guillery's method is similar to Brinell's, consisting in measuring 
 the indentation produced by a small ball by the pressure exerted 
 by Belleville springs under a determined deflection. Foeppl's 
 method consists in testing the metal or substance with itself; 
 two pieces are specially prepared and pressed together under a 
 constant load, the indentation thus produced varying inversely 
 as the hardness. Ludwik's method or cone test depends upon the 
 impression produced by forcing in, under constant load a circular 
 cone with 90 angular opening. The Amsler-Laffon machine 
 employed a 90 rounded cone which is forced into the material 
 under constant load and the depth of impression shown on a 
 graduated scale by a needle indicator. 
 
 Dynamic Indentation or Driving -in Method. Shore's method 
 depends upon the use of an instrument. known as a scleroscope 
 which consists essentially of a small diamond-pointed hammer 
 falling freely in a graduated glass tube from a constant height 
 on the surface of the object, the hardness (or rather the elastic 
 quality termed the coefficient of restitution) of which is measured 
 by the height of the rebound. By multiplying the scleroscope 
 number by 6 an approximate conversion to the Brinell number is 
 secured; it must be borne in mind, however, that exactly the 
 same qualities are not determined as one test is dynamic while 
 the other is static. The Keen impact ball tester consists of a 
 hardened ball secured at the end of a rod; this rod serves as a 
 guide for a weight falling from a height of about 3 feet, the blow 
 which it delivers serving to force the ball into the material upon 
 which it rests. The amount of impression is then measured. 
 The Brinell meter depends upon the comparison with a standard 
 specimen by producing an impression by the blow from a hand 
 hammer. The Pellin hardness -testing machine is a ball held 
 in a weighted frame which is allowed to fall on the sample, and 
 the diameter of the impression is measured. In Fremont's 
 method a weight, with a specially shaped point, is allowed to fall 
 on the object, and the indentation is measured. The Ballantine 
 method is carried out with an instrument in which a cylinder of 
 lead is supported on a cylindrical anvil, the lower end of which is 
 pointed and rests upon the material to be tested. A weight or 
 hammer is allowed to fall on the lead cylinder, and acts through 
 it upon the anvil which is driven into the sample. The deforma- 
 tion of the lead is inversely as the hardness of the sample. 
 
 Abrasive Hardness or Surface Scratching. Moh's scale was 
 devised to determine the relative hardness of mineral substances, 
 based on the fact that an object will scratch one of equal or less 
 hardness, but not one which is harder (see page 480). 
 
TESTING 
 
 479 
 
 * 
 
 . 
 
 " 
 
 vn o v 
 go, a 
 
 .n 
 c 
 M OT 
 
 .g K-i 
 
 oooooooooooooo 
 oooooooooooooo 
 
 <N t^ N oo >rj w oo vO * N O Oioo t- 
 
 O r~ * M oo O <* w 00 
 
 O< I- /> PO w 0> 
 
 ^ 
 
 iovO\O t^ t^oo 00 O> Oi 
 
 ot/sotooiflOi^oiooirtOio 
 
 ro'^^f^J'to 100 ^O r- r^oo oo O\ C\ 
 
 OOOOOOOOOOOOOOOOOOOO 
 OOOOOOOOOOOOOOOOOOOO 
 M rooo vO oo cs oo r~-oo M \o ro N ^ rj-oo ro Ov r^ 10 
 
 PO r^ N i> PO 
 
 M O OO t^O IO Tj- p<5 (N H O 
 
 OvOO r^ 
 NINN 
 
 fO ro 1^5 r5 (*3 ro ro PO fO f3 PO fO ro 
 
 OOOOOOOOOOOOOOOOOOOO 
 OOOOOOOOOOOOOOOOOOOO 
 
 10 C< M M PO\O Ovoi-ioOflttPO<NPOPO"lOOOw 
 
 OiOO 00 00 t~- 
 
 X 
 
 o C 
 * >H 
 
 M .g 
 ~ ST 
 
 s 
 
 c 
 
 O 
 u 
 
 O 
 
 PJ{ ^ 
 W o 
 
 8 I 
 
480 TESTING 
 
 r. Talc. 
 
 2. Rock salt. 
 
 3. Calcite. 
 
 4. Fluorspar. 
 
 5. Apatite. 
 
 6. Orthoclase. 
 
 7. Quartz. 
 
 8. Topaz. 
 
 9. Corundum. 
 10. Diamond. 
 
 Behren's scale adapted for metals, and based on the use of 
 sharp-pointed needles for testing, is as follows: 
 
 1 . o, Lead. 
 1.7,' Tin. 
 
 2 . o, Tin with iron, 
 i . 5 to 2.2, Hard lead. 
 2.5, Zinc. 
 
 3.0, Copper. 
 
 2.1, Brass wire. 
 
 3.3, Gun metal (bronze). 
 
 3.5, Bronze with 12% tin. 
 
 3.7, Bronze with 18% tin. 
 
 3 . 7 to 3 . 9, Iron wire. 
 
 4 . o, Needles tempered yellow. 
 
 5 . o, Needles tempered blue. 
 
 5 . o to 5 . 5, Sewing needles. 
 
 6 . o, Drill steel tempered yellow. 
 6 . 2 to 6 . 5, Chrome steel. 
 
 7.0 to 7. 3, Ferro-chrome. 
 
 Certain of the materials, at least, are too variable to make this 
 scale anything more than approximate. 
 
 Marten's test (hardness tester) depends upon the width of 
 scratch produced by dragging across the surface of the material 
 a diamond point under a definite load. .Turner's method is 
 similar to the above except it depends upon the weight necessary 
 to produce a visible scratch; the instrument employed is termed a 
 sclerometer. Bauer's method is based on the depth of penetra- 
 tion of a drill operating under constant conditions of speed and 
 pressure. - Keep's hardness test is similar to Bauer's, an auto- 
 graphic record being taken of the progress of the drill. In 
 Jagger's method an instrument called a microsclerometer is used. 
 This is a small weighted drill provided with a diamond point, and 
 the depth of the hole produced by drilling for a certain length of 
 time (at constant speed) is measured. It is intended to be used 
 in connection with a microscope for determining the relative 
 hardness of the microscopic constituents of metals. Wearing 
 tests may take the form of abrading a specimen under constant 
 load by means of a grinding wheel or revolving disk covered with 
 a suitable abrasive. Methods employed by Saniter, Stanton 
 and Norris consist essentially in subjecting cylindrical specimens 
 to a rubbing action by rotating them against other material. 
 
TESTING 481 
 
 Dynamic Tests. Those in which the load is suddenly or re- 
 peatedly applied, as opposed to static tests where the load it 
 gradually applied. They are usually divided into (a) impact 
 tests where the test specimen is subjected to a blow, and (b) 
 endurance tests where the stresses are repeatedly applied either 
 in the same or in alternate directions. They are used to deter- 
 mine the toughness (or absence of brittleness) of material, 
 particularly those going into moving parts which are subjected 
 to such conditions in actual service. The tests may be carried 
 out on full-size objects, such as car axles or pieces of rail, or on 
 small sections cut out and especially prepared. 
 
 Impact Tests. Also termed shock tests, percussion tests, 
 falling weight tests, drop tests, drop weight tests, hammer tests, 
 or impact crushing tests. Johnson says "The unit of measure, 
 in impact tests is the foot-pound (or the kilogrammeter) . This 
 energy cannot be measured in pounds, and no scheme of equiva- 
 lents can be devised between the foot-pound units of an impact 
 test and the pound units of a static test, although this has often 
 been attempted. There is no relation between the resistance 
 to shock and the resistance to a static load, since there is no 
 relation between the total area of a stress diagram and its stress 
 coordinate. The attempt which is often made, therefore, to 
 equate these two kinds of resistance is as foolish as the ancient 
 practice of estimating the discharge of stream, or aqueduct, or 
 pipe, from its cross section alone." In bridge design, for example, 
 the coefficient of impact is a number by which the calculated 
 static stresses are multiplied in order to take care of the increase 
 to be allowed for impact stresses. The specimen, either full-size 
 or of reduced section, rests on supports a certain distance apart 
 and the hammer, tup or bob strikes it midway. The specimen 
 may be required to withstand one or more blows without rupture, 
 or the energy (striking or impact energy) may purposely be 
 made more than sufficient to effect rupture (single-blow-test), 
 in which case the residual energy is measured, the difference 
 representing the absorbed energy, indicating the energy of 
 deformation, work of deformation, or specific work of rupture. 
 Car axles are tested on a drop test machine, ordinarily resting on 
 supports at a distance of 3 feet between centers, with a tup weigh- 
 ing 2240 pounds falling freely from a height which varies accord- 
 ing to the size of the axle; they are turned 180 about their axis 
 after the first, third, fifth, etc., blow, according to the number 
 which must be withstood. Usually the deflection at the center, 
 measured from a straight line between the journal collars, must 
 not exceed a prescribed maximum after the first blow. Rails 
 are tested in a similar manner, usually resting on their base; 
 a deflection requirement is also customary. In some cases the 
 ductility (ductility test) is determined by measuring the increase 
 between marks previously placed on the base (or lower portion) ; 
 a minimum percentage must be shown. Cast iron car wheels 
 are sometimes tested on a wheel breaker, resting flange down on 
 three supports spaced 120 degrees apart, the tup falling centrally 
 on the hub, and a certain number of blows to be withstood 
 31 
 
482 TESTING 
 
 without rupture. A special form of impact test is what is known 
 as proof testing. This consists in subjecting all the objects, 
 before being accepted or placed in service, to a blow less than will 
 produce any permanent distortion. This may take the form of a 
 modified axle test or of allowing the object itself to drop from a 
 specified height; it may also be struck with a hand hammer or 
 sledge (peening test). The specimen is frequently cut away in 
 some form of notch at the point where it is intended to break it. 
 The resistance to rupture is therefore sometimes termed notch 
 toughness. Owing to the variable results due to the different 
 forms of notch and also the fact that it is very difficult to insure 
 uniformity, a plain bar is preferred by many; Me Adam, for 
 example, recommends a plain bar to be sheared by the impact 
 applied by a pendulum hammer (impact shear test); this intro- 
 duces a single kind of stress instead of a combination, and in 
 addition to avoiding slight variables in the notch is much simpler 
 to carry out. 
 
 Of the tests producing rupture one of the best known is the 
 Charpy test, which employs a machine of that name, also termed 
 the Charpy pendulum hammer; the difference in swing (number 
 of degrees), after passing the lowest point, when a specimen is 
 broken from what would have occurred without, is the measure 
 of the absorbed energy. The Fremont machine is similar in 
 principle, the tup, however, falling vertically, and the residual 
 energy being measured by means of a scale and indicator. Other 
 similar tests of the one-blow method are those of Russell, Izod, 
 and Seaton; tests of the many-blow method include those of 
 Breuil, Yarrow, Seaton and Jude, Brinell and Wahlberg, Ruelle, 
 and Stanton. 
 
 Endurance Tests. Also termed fatigue tests, vibratory tests or 
 repetitive stressing. In Wohler's tests the specimen was not 
 loaded beyond the elastic limit and the stresses might be applied 
 all in one direction (from zero to a maximum, or from one load 
 to a greater load), or first in one direction and then in the other 
 (as from tension to compression). The number of repetitions or 
 alternations of different stresses to produce rupture served to 
 indicate the fatigue properties of the material in question. 
 Where an infinite number of repetitions would be necessary with 
 a certain stress, below that figure is sometimes termed the Wohler 
 range of entire resistance to fatigue. The specimens are usually 
 not stressed beyond the elastic limit, although in some forms of 
 test such is the case. The piece may be vibrated by a recipro- 
 cating or rotational movement. Machines and tests have been 
 devised for alternate bending by Stead, Sankey, and Amsler- 
 Laffon; for rotational stresses by White and Souther; for vibra- 
 tion by Arnold, etc. 
 
 Miscellaneous Methods. Ballistic tests, also termed firing 
 tests and proof tests, are employed in connection with armor 
 plate and projectiles. The armor plate must withstand the 
 attack of the prescribed number of standard projectiles, and the 
 projectiles, depending upon their type, must meet various condi- 
 tions, such as the penentration of a certain thickness of armor, 
 
TESTING 483 
 
 break up on detonation into a rninimum number of fragments 
 (fragmentation test) etc., in addition to resisting deforma- 
 tion while in the gun. It was at one time common practice to 
 take a sample billet from each heat and roll it down into a round 
 of about %" in diameter, from which pieces were taken for tensile 
 tests which were considered as indicative of the qualities of the 
 other material produced. This was known as the billet test, 
 but has been abandoned as not truly representative. A compara- 
 tor is an instrument for determining the coefficient of expansion 
 of solids by comparison with a standard. A conductometer is 
 an instrument for determining conductivity for heat, electricity, 
 etc. A dilatometer is an instrument to measure changes in 
 volume on heating or cooling. 
 
 Ductility Tests. In addition to those described elsewhere, 
 the following might be mentioned. A British method is to 
 specify the sum,of the elongation (in percent) and the tensile 
 strength (in gross tons) to be not less than a given value; for 
 example, with a range in tensile strength of 35 to 40 tons the 
 actual tensile strength plus the elongation (percent in 2") 
 must be not less than 60. The Tetmayer formula (or a similar 
 requirement) sometimes found in foreign specifications, is that 
 the product of the elongation (in millimeters) in a length of 200 
 millimeters, and the tensile strength (in kilograms per square 
 millimeter) must equal or exceed, say 750. A ductilimeter is the 
 term sometimes applied to an instrument to measure ductility. 
 A dynamometer is an instrument to measure the amount of work 
 developed as in the case of an engine, motor, etc. For example, 
 a form known as a Prony brake (brake test) to determine the 
 horse power which an engine can develop consists in clamping a 
 frictional brake to the fly wheel or shaft so tightly that it can 
 barely revolve; the torque is counterbalanced by weights. 
 Keep's tests were suggested by him as a method for a mechanical 
 analysis of the properties of cast iron based on the variations in 
 the amount of shrinkage caused by different amounts of silicon 
 present. The nick and break test (fracture test) sometimes used 
 for rails, consists in nicking and breaking a piece for the purpose of 
 detecting any internal flaws or defects by a visual examination. 
 The oncosimeter is a special form of instrument in which the 
 force acting on a metal ball suspended in a molten metal by a 
 spiral spring is measured; in this way it was shown that gray cast 
 iron and bisumth expand on solidification, while copper, silver, 
 lead, tin, and zinc contract (Desch). A test referred to as a 
 ringing test, resonance test, or sonority test, consists in striking 
 an object (sometimes while suspended) with a small hammer or 
 piece of metal to determine by the sound produced whether any 
 internal flaws or unsoundness exist. The schiseophone was a 
 modification of Prof. Hughes' induction balance, designed for 
 detecting flaws in rails, etc. A core is reciprocated longitudinally 
 within a coil and caused to strike the object. A continuous 
 current from a battery is sent through this coil, which is connected 
 with one of the coils in the induction balance. The other coil 
 on the balance is adjusted to reduce or abolish the sound in the 
 
484 TESTING MACHINE THERMOELECTRIC COUPLE 
 
 telephone. When the core gtrikes the object near a flaw, it is 
 claimed that the difference in the. quality of the sound is readily 
 detected. A shrinkage test (as applied to rails) is a requirement 
 that, after hot sawing, the shrinkage shall not exceed a specified 
 amount varying with the ordered (cold) length and the weight 
 or design of the section. The spark test is a method worked out 
 by J. F. Keller for distinguishing different metals, particularly 
 different types and grades of iron and steel, by the appearance 
 and nature of the spark thrown off when a sample is held against 
 a grinding wheel, or produced by similar means. The stremma- 
 tographis an instrument devised by Dr. P. H. Dudley to measure 
 the stresses and record the effect on the rails caused by a passing 
 train. Cast iron is usually tested transversely with an arbitration 
 bar (designed and advocated by the American Foundrymen's 
 Association), i%" in diameter and 15" long, which is cast from a 
 sample of the metal in a special mold under prescribed conditions. 
 In testing, the supports are 12" apart, the load applied at the 
 middle, and the deflection at rupture (cross breaking strength) 
 noted. 
 
 Testing Machine. See page 469. 
 
 Tetarto Prismatic System. Of crystallization: see page 120. 
 
 Tetmayer Formula. See page 483. 
 
 Tetrad. See page 86. 
 
 Tetragonal System. Of crystallization: see page 120. 
 
 Tetratomic. See page 87. 
 
 Tetravalent. See page 86. 
 
 Texture. See page 125. 
 
 Thalpotassimeter. See page 210. 
 
 Theodossief Process. See page 230. 
 
 Theoretical Chemistry. See page 81. 
 
 Thermal Analysis. See page 284. 
 
 Thermal Capacity. See page 201. 
 
 Thermal Chemistry. See page 82. 
 
 Thermal Conductivity. See page 200. 
 
 Thermal Crack. See Crack. 
 
 Thermal Equilibrium. See page 327. 
 
 Thermal Metamorphism. See pages 122 and 271. 
 
 Thermal Method. Of determining critical points: see page 265. 
 
 Thermal Refining. See page 213. 
 
 Thermal Resistance. See page 200. 
 
 Thermal Stability. See page 275. 
 
 Thermal Transformation. See page 326. 
 
 Thermal Treatment. Heat Treatment. 
 
 Thermal Unit. See page 199. 
 
 Thermally Metastable State. See page 281. 
 
 Thermit (Thermite); Process; Weld. (i) For reducing metals: 
 see Goldschmidt Process; (2) for producing sound ingots: see 
 page 6 1 ; (3) for welding: see page 504. 
 
 Thermochemistry. See page 82. 
 
 Thermo-couple. See page 208. 
 
 Thermo -elastic Properties. See page 330. 
 
 Thermoelectric Couple. See page 208. 
 
THERMOELECTRIC THWIMG PYROMETER 485 
 
 Thermoelectric Method. For determining critical points: see 
 
 page 266. 
 
 Thermoelectric Pair. See page 208. 
 Thermoelectric Pyrometer. See page 208. 
 Thermoelectric Telescopes. See page 207. 
 Thermo -element. See page 208. 
 Thermogage, Morse. See page 207. 
 Thermograph. See page 205. 
 Thermolabile. See page 204. 
 Thermolysis. See page 82. " 
 Thermo -magnetic Selector. See page 210. 
 Thermo-metallurgy. See page 82. 
 Thermometer. See page 205. 
 Thermometric Conductivity. See page 200. 
 Thermometric Heat. See page 199. 
 Thermometric Scales. See page 204. 
 Thermometrograph. See page 205. 
 Thermometry. See page 205. 
 Thermoneutrality. Law of: see page 201. 
 Thermophone, Wiborgh's. See page 210. 
 Thermopile. See page 207. 
 Thermoradiometer. See page 205. 
 Thermoscope. See page 205. 
 Thermostabile. See page 204. 
 Thermo -tension. Subjecting red hot metal to high tensile stress 
 
 which is maintained during cooling. 
 Thicken. To expand the end of a tube which is to be threaded, by 
 
 an amount equal to the depth of the thread. 
 Thickness. (i) Of plates: gage; (2) of molten slags, etc.; the degree 
 
 of viscosity or fluidity. 
 Thiel Process. See page 388. 
 Thin Lined Blast Furnace. See page 27. 
 Thiosulphate Process. See page 96. 
 Third Order Cells. See page 121. 
 Thomas Converter. See page 24. 
 
 Thomas or Thomas-Gilchrist Pig Iron. See pages 343 and 346. 
 Thomas-Gilchrist Process. See page 15. 
 Thomas (G. C.) Process. See page 73. 
 Thomas (J. W.) Process. See page 319. 
 Thomas (S. G.) Process. See page 15. 
 Thompson Process. See page 118. 
 Thomson Effect. See page 209. 
 Thomson Process. See page 503. 
 Thorn. See page 128. 
 Three-high Mill. See page 408. 
 Three-pass Stove. See page 34. 
 Threw Pyrometer. See page 210. 
 Throat. Of a blast furnace: see page 27. 
 Thurston's Formulae. For tensile strength: see page 339. 
 Thundergust Forge (obs.). An irreverent term formerly applied 
 
 to forges blown with a trompe. 
 Thwing Pyrometer. See page 207. 
 
486 TIEMANN'S FORMULA TON 
 
 Tiemann's Formula. For quality: see page 341. 
 
 Tilt Hammer. See Hammer. 
 
 Tilt (Tilted) Steel. Steel hammered with a tilt hammer; the term is 
 now restricted to blister steel which has been hammered. 
 
 Tilter. See page 411. 
 
 Tilting Converter. See page 17. 
 
 Tilting Furnace. See page 312. 
 
 Tilting Table. See page 408. 
 
 Time. Influence of on strain beyond the elastic limit: see page 472. 
 
 Timp. See page 32. 
 
 Tin. Sn; at. wt, 119; melt, pt, 228 C. (442 F.); sp. gr., crystal- 
 line, 7.2, amorphous, 5.8. It is not found in the free state. 
 When pure it is a white, soft, ductile metal. It is not readily 
 oxidized at ordinary temperatures and, for this reason, either 
 alone or alloyed with lead, is used for coating sheets (see pages 
 429, 432). It combines with iron in all proportions, but these 
 alloys are not of importance (see page 453), and ordinarily it 
 occurs in steel only as an impurity. 
 
 Tin Bar. See page 429. 
 
 Tin Mill. See page 430. 
 
 Tin (Tinned) Plate; Sheet. (i) General: see page 429; (2) manu- 
 facture of: see page 431. 
 
 Tin Plate Bar. See page 429. 
 
 Tin Plating. See page 371. 
 Pot. 
 
 Tin Pot; Tinning Pot. See page 431. 
 
 Tin Steels. See page 453. 
 
 Tinman's Pot; Wire. See page 432. 
 
 Tinting. Heat tinting: see page 288. 
 
 Tintometer. An instrument for matching colors, e.g., in colori- 
 metric determinations. 
 
 Tipping Converter. See page 17. 
 
 Tipping Furnace. See page 312. 
 
 Titanate Ore; Titanic Iron Ore. See page 245. 
 
 Titanium. Ti; at. wt., 48.1; melt, pt., 3000 C. (5432 F.); sp. gr., 
 3.54. It is never found uncombined. The pure metal is very 
 hard to produce on account of its great affinity for oxygen and 
 nitrogen, and is merely a chemical curiosity. It is obtained as an 
 alloy with iron, called ferro-titanium (seepage 355), and is used 
 to a certain extent as an addition to steel; it alloys with iron in all 
 proportions. 
 
 Titanium Steels; Titanium-treated Steels. See page 453. 
 
 Ton. Owing to the different kinds of ton it is always necessary to 
 specify which one is intended, and it is well to give the equivalent 
 in pounds avoirdupois as well as the name. The names and 
 values are as follows: short or net ton, 2000 pounds; long or gross 
 ton, 2 240 pounds (this is the British standard, and is always meant 
 when "ton" is referred to in British publications); a special long 
 ton of 2268 pounds, sometimes used for sand cast pig iron, \Y% 
 above the ordinary long ton being added to represent approxi- 
 mately the adhering sand; double gross ton (obs.), 2464 pounds, a 
 weight 10% above that of the ordinary long ton; metric ton, 
 1000 Kg., equivalent to 2205 pounds, nearly. 
 
TONNAGE TRANSVERSE DEFORMATION 487 
 
 Tonnage (Eng.). See page 472. 
 
 Tool Steel. See page 445. 
 
 Tool Temper. See Temper. 
 
 Top. (i) Of a blast furnace: see page 27; (2) of an ingot or piece: 
 
 seepage 115. 
 
 Top Casting. See page 57. 
 Top Cut; Discard. See Discard. 
 
 Top Heating; Insulation; Lag. Of ingots: see page 59. 
 Top Pouring. See pages 57 and 299. 
 Top Pouring Ladle. See Ladle. 
 Top Replenishment. See page 59. 
 Torpedo. In blast furnace practice: see page 35. 
 Terrified. See page 73. 
 Torsiometer. See page 477. 
 Torsion. See page 330. 
 Torsion Test. See page 477. 
 Torsional Resilience. See page 331. 
 Torsional Strength. See page 330. 
 Total Carbon. See Carbon. 
 Total Cementation. See page 67. 
 Total Cementite. See page 273. 
 Total Ferrite. See page 272. 
 Total Heat. See page 202. 
 Tough Fracture. See page 178. 
 Tough Hardening. See page 232. 
 Tough Hardness. See page 452. 
 Toughened Cast Iron. See Semi-steel. 
 Toughening. See pages 230 and 232. 
 Toughness. See pages 331 and 481. 
 Tourangin Process. See page 147. 
 Track Scales. Heavy scales for weighing railroad cars. 
 Traction Test. See page 469. 
 Train. Of rolls: see pages 406 and 409. 
 Transcarburization. See Carbon. 
 Transcrystalline Deformation. See page 282. 
 Transcrystalline Fracture. See page 178. 
 Transcrystalline Rupture. See page 282. 
 Transfer Caliper. See page 187. 
 Transfer Process. See page 21. 
 Transference. See page 81. 
 Transference of Heat. Law of: see page 221. 
 Transformation; Curve. See pages 81 and 326. 
 Transformation Point. See page 264. 
 Transformation Strains. See page 332. 
 Transfusion. Repouring: see page 21. 
 Transition. See pages 81 and 271. 
 Transition Point. See page 264. 
 Translation. See page 81. 
 Translation Banding. See page 127. 
 Transmutation. See page 81. 
 Transpiration Pyrometer. See page 210. 
 Transverse Deformation. See page 337. 
 
488 . TRANSVERSE ROLLING TRUE FUSION 
 
 Transverse Rolling. See page 414. 
 
 Transverse Rupture. See page 336. 
 
 Transverse Seam. See Seam. 
 
 Transverse Strain. See page 337. 
 
 Transverse Strength. See page 330. 
 
 Transverse Test. See page 477. 
 
 Transverse Test Piece. See page 469. 
 
 Treading; Treading Floor. In the manufacture of crucibles: see 
 page ii2. 
 
 Treatment Crack. See page 222. 
 
 Treatment for Grain Size and Carbon. See page 218. 
 
 Trebles. Of sheets: see page 433. 
 
 Tree-like Crystals. See page 122. 
 
 Tressider Process. (i) Armor plate: see page 9; (2) heat treat- 
 ment: see page 230. 
 
 Triad. (i) In chemistry: see page 86; (2) in meteorites: see page 
 291. 
 
 Trial Bar. See page 70. 
 
 Triatomic. See page 87. 
 
 Triaxial Diagram. See Curve. 
 
 Tribasic. See page 87. 
 
 Triblet (Eng.). (i) A smith's tool, being a round rod, slightly 
 tapered, which is used as a mandrel around which rings and nuts 
 are finished upon the anvil; (2) the steel core upon which tubes 
 are drawn to produce a smooth interior surface of uniform 
 diameter (Horner). 
 
 Trick, Davis, Daniel, and Phillips Process. See page 380. 
 
 Triclinic System. Of crystallization: see page 120. 
 
 Triclinohedral System. Of crystallization: see page 120. 
 
 Trimetric System. Of crystallization: see page 120. 
 
 Trimorphism. See page 121. 
 
 Trio Mill. See page 408. 
 
 Trip Hammer. See Hammer. 
 
 Tripartite Nature of Metals. See page 127. 
 
 Triple-melting Process. See page 75. 
 
 Triplex Process. Sometimes applied to a process involving refin- 
 ing in three stages as (a) acid Bessemer, (6) basic open hearth, and 
 (c) basic electric. 
 
 Trivalent. See page 86. 
 
 Troilite. See page 292. 
 
 Trolley. (i) A two-wheeled truck for carrying puddle balls, etc.; 
 (2) on an electric crane, the part carrying the hoisting drum which 
 runs back and forth. 
 
 Troostite. See page 276. 
 
 Troostp-Sorbite. See page 277. 
 
 Troostitic Martensite. See page 276. 
 
 Tropenas Converter; Process. See page 24. 
 
 Trosca Process. See page 147. 
 
 Trough (Eng.). Same as pot in the cementation process, q.v. 
 
 True Calorie. See page 199. 
 
 True Elastic Limit. See page 470. 
 
 True Fusion. See page 201. 
 
TRUE PEARLITE TUBES 489 
 
 True Pearlite. See page 273. 
 
 True Stress. See page 332. 
 
 True Welding. See page 501. 
 
 Trunnel Head. See page 95. 
 
 Tschernoff's Point. See page 265. 
 
 Tschernoff's Process. See page 233. 
 
 Tuaran (obs.). Tuyere. 
 
 Tub (obs.). Ladle. 
 
 Tubes; Tubing. Tubes or pipes are long hollow metallic cylin- 
 ders. The technical distinction between the two is that tubes 
 are rated according to the outside, and pipes according to the 
 inside, diameter but, in general, the two terms are used inter- 
 changeably. Cast iron pipe is necessarily cast in molds, the 
 center being cored out. Welded and riveted pipes are made 
 from plates of steel or wrought iron called skelp which are rolled 
 up longitudinally into shape and the edges welded or riveted 
 together. Close-jointed skelp is the name sometimes given to a 
 tube in which the edges of the skelp are brought close together, 
 but are not fastened. If the skelp is bent into form spirally, 
 depending upon the method of fastening the edges, it is known as 
 spirally welded or spirally riveted pipe. In the welding, depend- 
 ing upon whether the edges simply come together, or overlap, 
 butt welded or lap welded pipe is produced, the former being 
 generally restricted to sizes up to about 3" in diameter, while the 
 latter method is used for sizes up to 36". The line of the weld is 
 frequently called the seam. 
 
 Butt Welding. The process of butt welding consists in draw- 
 ing the highly heated skelp through a die or bell having 
 an opening of the exact size of the outside of the pipe, which 
 serves to bend the skelp into form and at the same time pro- 
 duce the pressure necessary for effecting the weld. In modern 
 practice tongs are thrust through the bell and grip the end of 
 the skelp which has previously been cut to a tapered point, 
 the other end of the tongs being attached to a buggy or car- 
 riage moved forward by an endless chain. The bell is kept 
 in position by resting against a stop. In the old method, known 
 as tag butt welding, in place of the tongs, a rod was welded 
 directly to the end of the skelp, being subsequently cut off. 
 A falling seam is a depression on the top (outside) of the weld due 
 to scant width of skelp; a deep seam is somewhat similar, but the 
 depression occurs on both sides, due to round edges on the skelp. 
 Lap Welding. In this method the edges of the skelp are 
 usually slightly beveled or tapered (scarfed) so when they 
 overlap there will not be too great an excess of metal. The 
 skelp in this case is always bent (hot) to form in a separate 
 operation called piping (rarely skelping). Formerly a machine 
 called a skelper (from which the word skelp is derived) or 
 crocodile was employed, consisting of a semi-circular trough 
 on which the skelp was laid, a round-nosed plunger forcing it 
 down. It was then removed and bent further into a circle. 
 In modern practice this bending is done in a set of three bending 
 rolls, one roll being placed between and slightly above two other 
 
490 TUBES 
 
 rolls, the height depending upon the diameter of the pipe. In 
 welding, as one edge of the skelp is on top of the other, two 
 rolls, with grooves corresponding to the exact diameter of the 
 pipe, are provided for supplying the necessary pressure which 
 is resisted on the inside of the pipe by a mandrel or ball having 
 the exact diameter of the inside of the pipe, and held in place 
 by a rod. Where the ball is on the same side as that on which 
 the pipe enters the rolls, the operation is called rolling off; if 
 on the opposite side, rolling on. For certain purposes, such as 
 boiler tubes, where the pipe is to be subjected to high internal 
 pressure, the whole welding operation may be repeated, the 
 product then being known as rewelded pipe. 
 
 After welding, both butt and lap welded pipes are made per- 
 fectly round by passing them through a set of grooved rolls, 
 called -sizing rolls, and are then made straight by passing them 
 through the straightening rolls. Tubes which are straightened 
 hot, particularly the larger sizes, are usually put through cross 
 rolls, consisting of two concave rolls, one above the other, and 
 with their axes set at an acute angle. They both revolve in 
 the same direction, which causes the pipe to rotate very rapidly 
 and at the same time to move slowly forward. The pipes are 
 then cooled on some form of cooling bed, cut to length, etc. 
 Another form of straightening machine is like an ordinary gag 
 press. There are two grooved rollers over which the pipe is 
 run, and a third roller, spaced between -the other two, is brought 
 down on the top of the pipe to take out any curvature. A 
 third type has one set of vertical and one set of horizontal 
 grooved rollers, of about six each, and spaced the right distance 
 apart for the given diameter of pipe. 
 
 Rifled pipe is a kind recently introduced for use in the trans- 
 mission of oil. It has spiral laminations rolled in it which 
 give the oil a whirling motion, a certain amount of water which 
 is present being thereby thrown to the periphery and lessening 
 the friction. Perrins process for making welded tubes consists 
 in first rolling puddled bars into a trough section, which are 
 then piled together in tubular form, with the longitudinal abut- 
 ting edges placed so as to break the joint, and the pile is then 
 rolled into a tube. 
 
 Seamless or weldless tubes are always manufactured of 
 steel on account of the great homogeneity necessary. They 
 are generally made from solid round billets which are heated 
 and then pierced by a mandrel (no longer drilled on account of 
 the cost), after which they are rolled over mandrels to obtain 
 the proper diameter and thickness of wall, much in the manner 
 already described for lap welding, except that a number of 
 passes are necessary. There are two methods of piercing: (a) 
 in the Mannesmann process a pair of special conical rolls (pilger 
 rolls), both of which revolve in the same direction, rotate the 
 billet very rapidly and at the same time drive it slowly forward 
 over a pointed mandrel situated between them. The action 
 here is very peculiar, as the hole is not produced by the mandrel 
 but by the rolls which, by exerting a pressure on the billet at two 
 
TUBES 
 
 491 
 
 diametrically opposed points, continuously changing, cause a 
 central cavity to open up, the mandrel serving simply to open up 
 the end and smooth the interior. This phenomenon is known as 
 internal rupture and may also be produced by hammering. A 
 different style of rolls to effect the same result has been designed 
 
 FIG. 64. The Mannesmann process for rolling weldless steel tubes. 
 
 by R. C. Stiefel. (b) In the Erhardt process a round-nosed 
 mandrel is forced longitudinally through a square billet enclosed 
 in circular dies, the difference in cross-sectional area between the 
 two giving the space necessary, for the metal displaced into the 
 wall of the billet by the mandrel. Tubes so produced may be 
 hot or cold drawn to final size, the principle being the same as in 
 
 FIG. 65. The Stiefel process for rolling weldless steel tubes. 
 
 wire drawing; but since a tube is hollow, it must be drawn over a 
 mandrel to prevent it from being crushed. In cold drawing 
 the tube is first pickled in a bath of dilute sulphuric acid, heated 
 by steam, to remove all scale which if left would spoil the surface 
 and scratch the dies. It is then rinsed in water and drawn 
 without further treatment. Tallow and sawdust, or some other 
 
492 TUBERCULAR CORROSION TURGITE 
 
 form of lubricant, are used both outside and inside. The tube 
 must be annealed and pickled after each drawing. For ordinary 
 purposes two drawings are usually sufficient, but for very thin 
 walls seven or eight may be required. With cold drawing the 
 operation is rarely commenced before the walls have been reduced 
 to %"; with hot drawing the thickness of the walls is not generally 
 carried below %" '. Seamless tubes made from billets range in size 
 from about 2" up to 5/^" outside diameter. Above this, to about 
 20", they are manufactured from plates, and, as a rule, in shorter 
 lengths. By this process a plate, sheared into a circle, is heated 
 and cupped, i.e., forced by a mandrel through a circular die, and 
 then after reheating, is similarly forced by another mandrel 
 through a succession of dies held in position in a heavy trough- 
 like machine until the thickneess of the wall has been reduced 
 considerably. Further reduction is effected by drawing in the 
 manner already described for seamless tubes made from billets. 
 Cylinders for gases, etc., to withstand great pressure, are made 
 by this method, the open end being swaged down and fitted 
 with a suitable cock. 
 
 Robertson's process is a method for producing seamless 
 tubes (somewhat similar to Erhardt's) by piercing longitudi- 
 nally a blank fitting a die, a pressure plate being held against 
 the far end to prevent the mandrel from tearing the piece. 
 The further rolling is as usual. 
 
 The Kellogg process is also for producing seamless tubes, 
 and consists in casting an ingot with a hollow center. This 
 is put over a mandrel and rolled out until the wall is of the 
 desired thickness. 
 
 Finished tubes are tested principally with hydraulic pressure. 
 Those which fail are known as blowers or leakers ; sand blowers 
 (lap welded) are those which have dirt in the weld; iron blowers 
 (lap welded), those which have longitudinal cracks. 
 
 Tubercular Corrosion. See page 106. 
 
 Tue Iron (obs.). Tuyere. 
 
 Tuiron (obs.). Tuyere. 
 
 Tumbler; Tumbling Barrel. See page 58. 
 
 Tungstate Ore. See page 245. 
 
 Tungsten. W; at. wt.; 184; melt, pt, 3267 C. 30 (5913 F. 
 54); sp. gr., 18.77. It is always found combined. The pure 
 metal is white but is not employed in that condition. It is 
 obtained as an alloy with iron, termed ferro-tungsten (see 
 page 355), and is used in the manufacture of certain special 
 steels (see page 450) ; it alloys with iron in all proportions. 
 
 Tungsten-Chrome Steels. See page 450. 
 
 Tungsten Hardenite. See page 275. 
 
 Tungsten Steels. See page 450. 
 
 Tunnel Head. See page 34. 
 
 Tunnel Kiln Process. See page 44. 
 
 Tup. (i) Of a hammer: see page 195; (2) of a drop test machine: 
 see page 481. 
 
 Turbo Blowers. See Blowing Engines. 
 
 Turgite. See page 244. 
 
TURK PROCESS TYROL PROCESS 493 
 
 Turk Process. See page 420. 
 
 Turn. A working period, also the men composing one shift. A 
 
 plant running on single turn works for ten to twelve hours per 
 
 day; double turn; two shifts of twelve hours each; triple turn: 
 
 three shifts of eight hours each. 
 Turn Down. (i) Of a converter: see page 17; (2) in rolling: see 
 
 page 412. 
 
 Turn Up. Of a converter: see page 20. 
 Turner Method. To determine hardness: see page 480. 
 Turner Process. See page 6r. 
 Turner Sclerometer. See page 480. 
 Turnover. Repeater, in rolling: see page 416. 
 Tuyere; Tuyere Arch; Tuyere Arch Cooler; Tuyere Block. See 
 
 page 31. 
 
 Tuyere Box; Brick. See page 17. 
 Tuyere of Combustion. See page 24. 
 Tuyere Plate. See page 135. 
 Tweer (obs.). Tuyere. 
 Twere (obs.). Tuyere. 
 Twin; Axis; Crystal. See page 124. 
 Twinning; Axis; Law. See page 124. 
 Twinning Plane. See page 123. 
 Twisted Guide. See page 41 2. 
 Two-high Mill. See page 408. 
 Two-pass Stove. See page 34. 
 Twyer; Twyere (Eng.). Tuyere. 
 Twynam Process. (i) Direct process: see page 147; (2) for steel: 
 
 see page 319. 
 Tying. See page 300. 
 Tymp; Plate; Stone. See page 32. 
 Type. Of steel: see page 455. 
 Tyrol Process. See page 79. 
 
u 
 
 U. Chemical symbol for uranium, q.v. 
 
 U. S. Gage. (i) Standard for sheet and plate iron, and steel: see 
 
 page 1 88; (2) for steel wire: see page 188. 
 chati 
 
 Uchatius Process. See page 113. 
 
 Uehling Process. See page 388. 
 
 Uhling-Steinbart Pyrometer. See page 209. 
 
 Ultimate Analysis. See page 82. 
 
 Ultimate Shortening. See page 336. 
 
 Ultimate Strength; Stress. See page 335. 
 
 Ultimate Structural Composition. See page 337. 
 
 Ultramicroscopic. See page 284. 
 
 Uncombined Carbon. See Carbon. 
 
 Underburdened. Of a blast furnace: see page 34. 
 
 Undercooling. See page 268. 
 
 Undercut. Of patterns: see page 296. 
 
 Understrained Ferrite. See page 216. 
 
 Unequal Cooling. See page 222. 
 
 Unequal Heating. See page 223. 
 
 Uneven Fracture. See page 179. 
 
 Unicellular Structure. See page 126. 
 
 Uniform Load. See page 468. 
 
 Uniformity. In heat treatment: see page 212. 
 
 Unit Crystal. See page 122. 
 
 Unit Stress. See page 333. 
 
 United States Gage. (i) Standard for sheet and plate iron and 
 
 steel: see page 188; (2) for steel wire: see page 188. 
 Univalent. See page 86. 
 Universal Mill. See pages 408 and 413. 
 Unsatisfied. See Satisfied. 
 Unsaturated Steel. See page 273. 
 Unsegregated Pearlite. See page 276. 
 Unstable Crystallographic Equilibrium. See page 217. 
 Unstable Equilibrium. See page 326. 
 Unstressed. See page 332. 
 Uphead. See Upset. 
 Upset. To enlarge the cross-section of a piece of metal at one end 
 
 by striking or pressing that end; to uphead. 
 Upper Freezing Point. See page 267. 
 Uptake. (i) In an open hearth furnace: see page 310; (2) in a gas 
 
 producer, the passage connecting the combustion chamber with 
 
 the gas main. 
 
 Upton's Equilibrium Diagram. See page 272. 
 Uranium.-*!!; at. wt., 138.5; melt, pt., 800 C. (1472 F.); sp. gr., 
 
 18.7. It is not found free in nature. When pure it is a heavy 
 
 494 
 
URANIUM STEELS UTRICULAR 495 
 
 white metal. It has recently had some application as an addi- 
 tion to steel (see Special Steels, p. 453). 
 
 Uranium Steels. See page 453. 
 
 Uses (Eng.)- A rough block (reduced from an ingot) to be made 
 into small forgings, or ready to be machined to final form. 
 
 Utricular. See page 120. 
 
V. (i^Volumej (2) chemical symbol for vanadium, q.v.; (3) point 
 of Brinell: see page 265. 
 
 V-weld. See page 502. 
 
 Vacuum Casting. See page 62. 
 
 Vacuum Gases (Howe). Those obtained on heating metal in 
 vacuo. 
 
 Vacuum Tuyere. See page 32. 
 
 Valence; Valency. See page 86. 
 
 Valence Formula. See page 86. 
 
 Valency Theory. Of passivity: see page 364. 
 
 Van Aller Process. See page 372. 
 
 Van der Waal's Formula. See Gas. 
 
 Van Riet Process. See page 60. 
 
 Vanadium. V; at. wt., 51.2; melt, pt, 1680 C. (3056 F.); sp. 
 gr., 6.025. It is a comparatively rare element and is always 
 found combined. When pure it is a white metal having a 
 great affinity for oxygen and nitrogen. Owing to the discovery 
 of large mineral deposits, it has recently come into considerable 
 use in the manufacture of special steels (see page 452); it alloys 
 with iron in all proportions, and is obtained commercially as 
 ferro-vanadium (see page 356). The element was first isolated 
 in 1803 by Del Rio who called it eurythronium ; its present name 
 was given in 1830 by Sefstrom. 
 
 Vanadium Hardenite. See page 275. 
 
 Vanadium Steels. See page 452. 
 
 Vanado-Fenite. See page 272. 
 
 Vapor. See page 202. 
 
 Vapor Pressure Pyrometer. See page 210. 
 
 Vapor Pyrometer. See page 209. 
 
 Vaporization. See page 202. 
 
 Variable Pressure Thermometer. See page 205. 
 
 Variable Volume Thermometer. See page 205. 
 
 Variability, Degree of. See page 327. 
 
 Vectorial Movement. See page 281. 
 
 Vehicle. Of a paint: see page 365. 
 
 Vein. See page 58. 
 
 Vein Stuff (Eng.). The gangue or matrix of an ore. 
 
 Velocity of Cementation. See page 67. 
 
 Velocity of Transformation. See page 265. 
 
 Vent Hole; Wire. See page 298. 
 
 Ventilation; Venting. See page 298. 
 
 Vertical Heating Furnace. See page 184. 
 
 Vertical Illumination. See page 285. 
 
 496 
 
VERTICAL REGENERATORS VUG 497 
 
 Vertical Regenerators. See page 312. 
 
 Vertical Shear. See page 336. 
 
 Vertical Testing Machine. See page 469. 
 
 Vessel. A Bessemer converter: see page 15. 
 
 Vessel Patching. See page 17. 
 
 Vibration. See page 333. 
 
 Vibrator Machine. See page 301. 
 
 Vibratory Brittleness. See Brittleness. 
 
 Vibratory Test. See page 482. 
 
 Vical's Experiment. See page 334. 
 
 Vickers Process. See page 118. 
 
 Villon Process. See page 374. 
 
 Violent Aeration. See page 107. 
 
 Violent Cement. See page 67. 
 
 Violle's Actinometer. See page 207. 
 
 Violle Calorimetric Pyrometer. See page 207. 
 
 Viscous Materials. See page 331. 
 
 Visible Color. See page 210. 
 
 Visual Analysis. See page 284. 
 
 Visual Microscopy. See page 284. 
 
 Vitreous Amorphous Phase. See page 281. 
 
 Vitreous Fracture. See page 179. 
 
 Vitreous Fusion. See page 201. 
 
 Vitricarbo. See page 398. 
 
 Vitriform Fracture. See page 179. 
 
 Vitriol. Oil of vitriol: commercial sulphuric acid. 
 
 Vivianite. See page 244. 
 
 Void. Pipe: see page 53. 
 
 Volatile Matter. See Fuel. 
 
 Voltaic Contact. That between unlike metals, causing an electro- 
 lytic action. 
 
 Voltex Process. See page 503. 
 
 Volume Force. See page 331. 
 
 Volume Increase. From quenching: see page 225. 
 
 Volumenometric Thermometer. :See page 207. 
 
 Volumetric Modulus of Elasticity. See page 335. 
 
 Volumetric Thermometer. See page 207. 
 
 Vom Baur Furnace. See page 165. 
 
 Von Maltitz Process. See page 388. 
 
 Von Nawrocki Process. See page 64. 
 
 Vug; Vug Crystals. A cavity in a casting, etc., and crystals found 
 in such cavities. 
 
 32 
 
w 
 
 W. (i) Chemical symbol for tungsten, q.v.; (2) point of Brinell: 
 
 see page 265. 
 
 W Structure. See page 291. 
 Wabbler. See page 407. 
 Wagner Process. See page 371. 
 Waidner and Burgess Pyrometer. See page 208. 
 Walker Process. See page 371. 
 Wall. One of the sides of a furnace; in a circular furnace, the 
 
 vertical portion. 
 
 Wall (Arthur) Process. See page 73. 
 Walled Cell. See page 121. 
 Wallerant's Process. See page 232. 
 Walloon Processes. See page 75. 
 Walrand Converter. See page 24. 
 Walrand-Delattre Converter. See page 24. 
 Walrand and Delattre Process. See page 23. 
 Walrand and Legenisel Process. See page 23. 
 Walrand Process. See pages 23 and 388. 
 Wanner Optical Pyrometer. See page 207. 
 Ward Process. See page 370. 
 Warm Blast. See Blast. 
 Warm Blast Charcoal Iron. See page 350. 
 Warner Process. (i) Basic Bessemer process: see page 23; (2) 
 
 for desulphurizing: see page 388. 
 Warped. See page 56. 
 Wash. (i) Wearing of molds: seepage 57; (2) coating for molds: 
 
 see page 298. 
 Wash Heat. A heat which causes the scale on the surface of a 
 
 piece of iron or steel to melt and run off; also called a cinder heat: 
 
 (2) used in the sense of reheating merely the outside of a piece* 
 
 where it has become slightly chilled from rolling or forging, the 
 
 interior being still sufficiently hot; (3) in open hearth practice; 
 
 see page 313. 
 
 Wash Metal. See page 384. 
 Wash Out Heat. See page 313. 
 Wash Pot. See page 298. 
 Wash Up. See page 298. 
 Wash-welding Temperature. See page 116. 
 Washburn and Moen Gage. See page 188. 
 Washed Metal; Pig. See pages 346 and 384. 
 Washer. See Ore. 
 Washing. (i) Of gas: see page 33; (2) see Wash Heat; (3) of ore, 
 
 q.v. 
 
 498 
 
WASHING PROCESS WATER GAS 499 
 
 Washing Process. Pig washing process: see page 383. 
 
 Wassell Process. See page 420. 
 
 Wassereisen (obs.). See Hydrosiderum. 
 
 Waste Gases. See page 202. 
 
 Waste-heat Oven. See page 96. 
 
 Waste Liquor. See Pickling. 
 
 Waste Wax Process. See page 301. 
 
 Waster. An article rejected on account of imperfections developed 
 in the course of manufacture; scrap. This term is applied more 
 especially to defective sheets and tin plates. 
 
 Water. H 2 O; it occurs in practically every non-metallic sub- 
 stance unless it is specially removed by drying (desiccation), 
 and is then often termed moisture. It may, so to speak, be 
 simply mixed, so that heating to a temperature slightly above 
 its boiling point will expel it: in this case it is called hygroscopic 
 moisture (rarely hygrometric water) or mechanically combined 
 water. The action whereby a solid substance parts with its 
 moisture upon exposure to ordinary air is termed efflorescence 
 (the substance is said to effloresce); where additional moisture 
 is taken up it is known as deliquescence (the substance is said 
 to deliquesce). Where the water is more closely bound and 
 appears to enter into a weak chemical combination, so that a 
 temperature considerably above its boiling point is necessary 
 to expel it, it is termed combined water, water of crystallization, 
 or water of combination; an example of this is copper sulphate 
 which is generally seen in the form of beautiful blue crystals 
 having the formula CuSO4-7H2O; upon drying at a fairly high 
 temperature, the water is driven off and a white powder results. 
 
 Water Annealing. See page 231. 
 
 Water Breast. See page 31. 
 
 Water Coating. See page 507. 
 
 Water of Combination. See Water. 
 
 Water of Crystallization. See Water. 
 
 Water Cooled; Cooling. See page 227. 
 
 Water Core. See page 299. 
 
 Water Crack. See Crack. 
 
 Water Dipping. See page 227. 
 
 Water Equivalent. See page 201. 
 
 Water Finish. The finish or appearance of machined metal ob- 
 tained when a small stream of water trickles upon the cutting 
 tool. 
 
 Water Gas. A fuel gas produced by the decomposition of steam 
 with incandescent carbon. The fuel is maintained in a thick 
 bed in an apparatus called a water gas producer (rarely simply 
 gas producer), and the process consists of two periods; during 
 the first period (sometimes called blowing up or blowing hot) 
 air is blown through the fuel until it becomes incandescent, 
 the gases formed being allowed to escape; in the second period 
 (steaming or blowing cold) the air is turned off and steam is 
 blown through the fuel, the gas so formed being led to the gas 
 receiver: this is kept up until the fuel is so much cooled that 
 the reaction becomes very imperfect. The theoretical compo- 
 
500 WATER HARDENING WELDED PIPE 
 
 sition of the gas is 50% each of hydrogen and carbon monoxide. 
 Ledebur gives the following as the usual range by volume: 
 
 Hydrogen ; 44.0 to 53.0% 
 
 Carbon monoxide 45 . o to 40 . o 
 
 Methane , 4 . o to o . o 
 
 Carbon dioxide i . 5 to 6.0 
 
 Nitrogen... 8.0 to i.o 
 
 Water Hardening. See page 227. 
 
 Water Hardening High Speed Tool Steels. See page 448. 
 Water Helve. See Hammer. 
 
 Water Jacket. A metallic casing through which water circulates to 
 keep the interior of a furnace wall from being corroded or burned 
 
 away, i.e., to keep it "cool." 
 Water Oil Gas. See Oil Gas. 
 
 Water Pot. See page 298. 
 
 Water Pyrometer. See page 207. 
 
 Water Quenching. See page 227. 
 
 Water Seal Producer. See Producer. \&?.. r 
 
 Water Tempering. See page 227. 
 
 Water Toughening. See pages 227 and 445. 
 
 Watery Fusion. See page 201. 
 
 Watson (J. J.W.) Process. See page 73. 
 
 Watts Process. See page 166. 
 
 Wave. See Flute. 
 
 Weak. Brittle, q.v. 
 
 Weak Iron. White, brittle pig iron. 
 
 Wearing Tests. See page 480. 
 
 Weathering. Exposure to the atmosphere; used in the case of ores 
 which are exposed for a considerable period (months or years) 
 to assist in their disintegration and in removing or oxidizing 
 impurities. 
 
 Webster's Formula. For tensile strength: see page 339. 
 
 Wedging Down. Of top-poured iron ingot molds; capped with 
 sand and an iron plate held in place by a wedge driven under a 
 bar passing through rings in the top of the mold. 
 
 Wedgwood's Contraction Pyroscope. See page 209. 
 
 Weigelin Process. See page 369. 
 
 Weigh Bar. See page 475. 
 
 Weight Percent. See page 83. 
 
 Weiss Process. See page 44. 
 
 Weld. See page 501. 
 
 Weld Iron. A term suggested for wrought iron but seldom used. 
 
 Weld Metal. A term suggested by Von Ehrenwerth for iron 
 products produced in a pasty (containing slag) condition. 
 
 Weld Steel. Iron containing sufficient carbon to be capable 
 of hardening greatly by sudden cooling, and in addition slag 
 bearing, because made by welding together pasty particles of 
 metal in a bath of slag, as in puddling, and not later freed from 
 that slag by melting. The term is rarely used (I. A. T. M.). 
 
 Welded Joint. See page 501. 
 
 Welded Pipe.- See page 489. 
 
WELDING 5 01 
 
 Welding. (a) Strictly a method of uniting two pieces of wrought 
 iron or steel by heating them to a temperature, moderately close 
 to their melting point (but without actual fusion), at which they 
 become pasty, and forcing them into intimate contact whereby 
 molecular cohesion takes place, producing a weld or welded joint. 
 (6) In recent years methods are included which employ actual 
 melting either of a substance which acts as a solder or of a portion 
 of one or both of the pieces which are to be united. Stead de- 
 scribes (a) or true welding as "the crystallizing into union of two 
 metallic surfaces when they are brought together under suitable 
 conditions. That such is the case is proved by microscopic 
 examination, for on polishing and etching sections of the united 
 metals, the crystals along the junction are found to be common to 
 each of the original pieces of metal. In perfect welding there is 
 no visible joint, for the line or plane of junction is occupied by 
 crystals, portions of which belong to one piece of metal and 
 portions of the same crystals to the other. When the boundaries 
 of the crystals are coincident with the juxtaposed plane surfaces 
 it is evidence of non- welding, which is equivalent to saying that 
 'unless the crystals become common to the two pieces there is no 
 welding' " (Stead's Law of Welding). 
 
 The temperature necessary for ordinary welding is a good white 
 heat (welding heat or temperature), say 1250 to 1350 C. (2280 to 
 2460 F.) for soft steel, and in some cases slightly higher for 
 wrought iron. As this makes the grain very coarse, hammering 
 or some other form of work is usually necessary to refine it; 
 annealing or some form of heat treatment alone i may in some 
 cases be sufficient (see Heat Treatment, page 231). Hammered 
 weld is the term sometimes used for such welds particularly to 
 distinguish them from those (chiefly electrical or thermit welds) 
 which are simply pressed together at a high temperature and 
 may, in consequence, have a coarse grain from not having been 
 worked down to a low temperature. By the Komrn method of 
 welding the union of the two pieces is produced within the fire 
 where the two conically pointed ends are in contact. The crust 
 of cinders is removed by blows applied to the butts which project 
 from the hearth, and since the two surfaces which are thus kept 
 pure cling to one another at once and unite, there is no opportu- 
 nity for a renewed oxidation. Rods which are welded in this way 
 do not separate under alternating torsional bending along the 
 faces welded, but they break across the axis of the rod, just like 
 rods which have not been welded (Bermann). At the moment of 
 welding it is essential to have the surfaces clean, i.e., free from 
 scale or dirt, to remove which a flux is commonly used, ordinarily 
 sand for steel and borax for wrought iron. The term welding 
 cinder is sometimes employed for one which is easily fusible and, 
 while protecting the surfaces from oxidation, will run out readily 
 when they are pressed together. It has been recommended to 
 have the surfaces convex to each other so they will at first touch 
 on a line near the middle and the liquid slag will be forced out as 
 the weld is formed instead of being inclosed as might easily be the 
 case if the surfaces were concave. The flux is sometimes formed 
 
502 WELDING 
 
 into a thin plate (welding plate) which is placed between the two 
 surfaces, and in this case is frequently of a special composition. 
 W. B. Middleton dips the pieces to be welded into a solution of 
 sodium silicate, after which they are heated and welded in the 
 usual manner. 
 
 The strength of a weld (i.e., of the material at the joint) is 
 almost never equal to that of the original section, although in 
 some cases, particularly with wrought iron, it may approach it 
 very closely. Defective welds may be caused by (a) heating too 
 high: burning; (b) heating too low: molecular cohesion not 
 effected; (c) not working sufficiently at the weld, back from the 
 weld, or both: brittle; (d) surfaces not clean; (e) sulphur too high; 
 (/") carbon too high. It should be appreciated that one of these 
 conditions may directly affect another; for example, if the carbon 
 is higher than usual the temperature cannot be so high without 
 danger of burning, but if too low good cohesion will not be se- 
 
 Lap or Scarf Weld Butt or Jump Weld 
 
 V 
 
 V-Weld V-Weld with Binder 
 
 Split Weld 
 FIG. 66. Types of weld. 
 
 cured. It is also of interest that experiments with relatively 
 high sulphur steel developed the fact that the temperature had 
 to be lower (or shorter time of heating under the same conditions) 
 than with low sulphur stock; the welds produced in this way were 
 entirely satisfactory. There are a number of types of weld 
 which are sufficiently explained by Fig. 66. 
 
 V-welds and V-welds with binder are sometimes called respec- 
 tively bird's-mouth welds, and glut welds. Cross welding, 
 employed in the manufacture of extra-long lengths of tubes, 
 consists in welding two pieces of skelp together at the ends before 
 bending and welding the edges. The line of the weld is called the 
 joint or sometimes the shut or, particularly in the case of welded 
 tubes, the seam. A cold shut is where the hammering has not 
 been carried far enough to obliterate the line or joint between the 
 
WELDING 503 
 
 two pieces: the weld is not smooth but otherwise may be all 
 right. 
 
 An experiment to show that welding may occur at a tempera- 
 ture only slightly above the upper critical point is known as 
 Coffin's weld or joint. It consists in taking a small bar of tool 
 steel, breaking it to obtain a fresh fracture (two pieces may also be 
 machined to produce clean surfaces fitting accurately), which 
 are then fitted together. They are wrapped in platinum foil 
 to prevent oxidation, and are heated with an ordinary Bunsen 
 burner (or otherwise) when the pieces will unite more or less 
 completely, unassisted by any hammering. 
 
 In ordinary (or "old-fashioned") welding the pieces are gener- 
 ally heated in a coke fire or in some form of regular heating fur- 
 nace. An oxy hydrogen flame (oxyhydrogen welding) is some- 
 times employed, which is the principle of Garut's process, and 
 more recently considerable application has been made of an 
 oxyacetylene flame (oxyacetylene welding), both of these 
 methods being chiefly applicable to small or thin pieces such as 
 sheets. Owing to the extremely high temperatures produced 
 such welds are sometimes referred to as hot flame welds ; the 
 temperatures are so high that frequently (and by intention) 
 actual fusion occurs. Oxyhydrogen and oxyacetylene cutting 
 are simply a further application of this possibility by melting 
 away the metal in order to remove portions of an object; with a 
 substance containing carbon (any form of wrought iron, cast iron 
 or steel) after a. point of incandescence is reached it is sufficient 
 to shut off the hydrogen or acetylene, as the case may be, and the 
 oxygen under heavy pressure will burn and fuse the metal in the 
 immediate vicinity, which is blown away. By employing a fine 
 jet a very narrow cut may be effected. 
 
 The necessary heat may also be supplied electrically (electric 
 welding) : (a) with an arc (arc welding) in which the pieces are 
 heated by direct contact or by radiation; (b) by the resistance of 
 the pieces themselves to the passage of the current (incandescent 
 welding or resistance welding); and (c) by electro -percussive 
 methods. Electric welding was first introduced by Elihu 
 Thomson in 1886, his process of incandescent welding consisting 
 in passing a heavy alternating current through the pieces to be 
 welded, the increased resistance at their point of contact (contact 
 welding) giving the necessary temperature at the joint. Other 
 contact systems were devised by Pontelec, Helsby, and Lagrange- 
 Hoho. In Bernardos' process an arc is formed between a carbon 
 rod (positive pole) and the metal (negative pole). Between the 
 pieces to be welded are placed small pieces of metal, such as 
 turnings, which melt and unite the pieces by soldering rather than 
 by true welding. Bernardos also suggested the application of a 
 magnet to deflect the arc between two electrodes, forming an 
 electric blast. This method (voltex process) was prefected in the 
 Zerener process. Somewhat similar to Bernardos' earlier 
 method was that of N. Slaviankoff for repairing broken pieces of 
 machinery, etc. The piece to be repaired is attached directly 
 to one pole of a dynamo, and small pieces of metal are melted by 
 
504 WELDING 
 
 the electric arc in a special tool attached to the other pole and fall 
 on the object in a molten state. 
 
 Spot welding is the fusing or welding together of relatively thin 
 sections by means of a single-phase alternating current, with the 
 electrode making a heavy contact pressure on the area being 
 welded. It is adapted especially to sheet metal work ranging 
 from the welding of fish plates to tram rails, to the lightest of 
 sections such as the sticking of handles to oil cans and kitchen 
 ware. The electrical contacts cover a small area similar to that 
 of a rivet, and, the points pinch the two pieces together like a vise. 
 A _ heavy current is then sent through this area and in a few 
 minutes produces a welding heat. It can be made to take the 
 place of riveting, requires no punching and is much quicker. It 
 can be applied to almost all kinds of metals and alloys except 
 that cast iron cannot be welded to cast iron. It is also possible 
 to heat and head rivets when set in the holes, and to produce soft 
 spots in hardened sheets (Iron Trade Review, Oct. 19, 1916, 781). 
 Electro -percussive welding (also called percussive electric 
 welding) is a recent development of electrical welding originated 
 by L. W. Chubb. The process is based on the principle of simul- 
 taneous condenser discharge and percussive engagement. In 
 the first apparatus the wires to be welded together, placed in the 
 grips of two hinged arms, were connected to the terminals of a 
 charged electrolytic condenser. When the arms were released 
 the wires came into contact and immediately discharged the 
 explosive condenser, the force of impact welding the ends to- 
 gether. In an improved apparatus, similar in construction to a 
 pile driver, the forge effect and velocity are capable of independ- 
 ent variation. It is claimed that the generation of heat is so 
 localized, so sudden and so intense, that there is no time for 
 unequal heat conduction through the shanks of the wires, and 
 the ends will be melted and even vaporized whether the melting 
 point of the metal is high or low. For this reason various metals 
 and alloys can be welded together independently of their electrical 
 resistance, melting point, or heat conductance (Journ. Inst. 
 Metals, 1915, II, 247). jii 
 
 Thermit welds are those where (a) the temperature is secured 
 by contact with the slag produced from thermit applied around 
 the joint and may in cases be high enough to cause actual or 
 partial fusion; or (b) where the molten metal produced from 
 thermit is used directly to form the joint. The Stroh steel 
 hardening process is stated to consist in depositing a layer of alloy 
 steel to secure a better wearing surface and may be of a depth 
 as required, uniting with the part so treated (Iron Age, May 2, 
 1912, 1080). The Simpson weld, intended as a method where 
 high-speed tool steel is to be united to a soft steel backing for 
 armor plate, etc., consists in the application of a section of copper 
 between the two sheets of steel; a mixture of charcoal, brown 
 sugar, and water is used as a flux and upon being subjected to a 
 temperature of 2000 F. (1095 G.) the copper combines with the 
 steel and forms a perfect weld (Iron Trade Rev., Aug. 17, 1911, 
 286). 
 
WELDING CINDER WHEEL SWARF 505 
 
 Soldering consists in joining two metals or alloys together by 
 means of a more soluble alloy (solder) or one to which they will 
 more readily unite than with each other. Ordinary or soft spider, 
 used for uniting non-ferrous metals such as lead, or principally 
 sheets of iron or steel, consists of approximately 2 parts of lead 
 and i part of tin. Wiping (of joints) is a term used principally 
 in plumbing work where the solder in a pasty, semi-molten condi- 
 tion is worked and pressed into the desired shape around a joint. 
 Hard solder consists of a mixture of copper and zinc, usually 
 about half and half, sometimes with a little tin added, and is used 
 for brazing or joining where greater strength is required than by 
 soldering but not so great as by welding. Autogenous welding or 
 soldering is really a form of soldering where two pieces of the 
 same metal, or alloy are united by limited fusion of the pieces 
 themselves without the addition of some other substance (except 
 a flux). The autogenous welding of lead pipe is sometimes called 
 lead burning. 
 
 Welding Cinder. See page 501. 
 
 Welding Flux. See page 501. 
 
 Welding Furnace. (i) A furnace in which pieces are heated for 
 welding; (2) a puddling furnace (obs.). 
 
 Welding Heat. See page 501. 
 
 Welding Plate. See age pso2. 
 
 Welding Process. Of coating: see page 372. 
 
 Welding Seam. See page 502. 
 
 Welding Temperature. See page 501. 
 
 Weldless Tube. See page 490. 
 
 Well. Hearth of a blast furnace: see page 27. 
 
 Wellman and Schwab Process. See page 388. 
 
 Welt. The covering strip used in butt riveting (Homer). 
 
 Wenstrom Mill. See page 420. 
 
 West Coast Hematite. See page 344. 
 
 West Sintering Process. See page 45. 
 
 Westman Process. See page 148. 
 
 Westphalia Gage. See page 188. 
 
 Wet Analysis. See page 82. 
 
 Wet Assaying. See page 82. 
 
 Wet Blacking. See page 298. 
 
 Wet Bottom. See pages 253 and 377. 
 
 Wet Brush. See page 298. 
 
 Wet Cleaning. Of gas: see page 33. 
 
 Wet Drawing. See page 508. 
 
 Wet Process. See page 82. 
 
 Wet Puddling. See page 374. 
 
 Wet Slag. See Slag. 
 
 Wet Washing. Of gas: see- page 33. 
 
 Weyl's Method. Of etching: see page 288. 
 
 Weyrauch's Formula. For tensile strength: see page 339. 
 
 Wheel Breaker. See page 481. 
 
 Wheel Burns. See page 1 10. 
 
 Wheel Swarf (Eng.). A mixture of silicious particles and partially 
 rusted steel obtained from the grindstones in cutlery grinding; it 
 
$o6 WHEELER PROCESS WIND BOX 
 
 is used in cementation furnaces as a lute to make the pots air- 
 tight. 
 
 Wheeler Process. See page 64. 
 
 Wheeling Theory. Of slip: see page 284. 
 
 Whiskers. Of coke: see page 96. 
 
 White Amorphous Sulphur. See Sulphur. 
 
 White Annealing. See page 431. 
 
 White Calorimeter. See page 201. 
 
 White Cast Iron. See page 342. 
 
 White Clay. See page 302. 
 
 White Crucible Process. See page 114. 
 
 White Edged Plate. See page 432. 
 
 White Ghost Lines. See page 289. 
 
 White Heart Casting; Malleable. See page 258. 
 
 White Heat. Color temperature: see page 210. 
 
 White Iron. (i) Grade of pig iron: see page 342; (2) tin plate: see 
 page 433. 
 
 White Iron Pyrites. See page 245. 
 
 White Ironstone. See page 244. 
 
 White Metal. See page 383. 
 
 White Pickling. See page 431. 
 
 White Pig. See page 342. 
 
 White Pot. (i) Kind of crucible: see page in; (2) in the manu- 
 facture of tin plate: see page 431. 
 
 White Refined Cast Iron. See page 383. 
 
 White-Souther Machine. See page 482. 
 
 Whiteley Process. See page 65. 
 
 Whiteley's Reagent. For etching: see page 287. 
 
 Whitesmith. See page 433. 
 
 Whitworth Armor Plate. See page 9. 
 
 Whitworth Process. For fluid compression: see page 63. 
 
 Wiborgh Air Pyrometer. See page 207. 
 
 Wiborgh's Thermophone. See page 210. 
 
 Wicket. The small hole in the door of an open hearth or other 
 form of furnace through which the interior can be inspected with- 
 out raising the door. 
 
 Widmanstatten (Widmanstattian) Lines; Structure. See page 291. 
 
 Wild. Of metal, usually steel, when overoxidized, causing it to 
 spit and fly. Spitting in the ladle is usually caused by a reaction 
 between the metal and the cinder; in the molds, by the violent 
 escape of gases while the metal is in a pasty condition. The 
 opposite condition is dead. 
 
 Wild Process. See page 64. 
 
 Wile Furnace. See page 165. 
 
 Willans Process. See page 388. 
 
 Williams Mill. See page 420. ;;:*:.?.; 
 
 Williams Process. See page 63. 
 
 Willis Process. See page 372. 
 
 Wills Converter. See page 25. 
 
 Wilson Process. For armor plate: see page 9; (2) direct process: 
 see page 148. 
 
 Wind Box. See page 17. 
 
WIND FURNACE WIRE 507 
 
 Wind Furnace. See page 183. 
 
 Winiwarter Process. See page 370. 
 
 Winslow Squeezer. See page 377. % 
 
 Wiper. In wire manufacture: see page 509. 
 
 Wiping. Kind of soldering: see page 505. 
 
 Wire. On tinned sheets: see page 432. 
 
 Wire. (i) The name given to small metal filaments (usually round) 
 produced in pieces of considerable length by drawing, i.e., suc- 
 cessively reducing (and thereby extending) the section by 
 repeatedly pulling it cold (cold drawing) through tapered holes 
 in a die or draw plate (block, die plate). Drawing is necessary 
 as it is impracticable to roll such small sections commercially. 
 (2) Wire is also the name given to rounds for helical springs 
 (particularly for railway work). 
 
 Billets are first reduced, in a rolling mill, to wire rods (rounds) 
 about 0.2" to 0.3" in diameter, which are coiled up into bundles. 
 
 . These bundles are placed in a pickling bath of dilute sulphuric 
 acid, heated by steam, to remove the scale, and are then trans- 
 ferred to the rinsing bath to remove the greater part of the acid, 
 after which they are put on a revolving frame and sprayed 
 with water still further to remove the acid; this causes a certain 
 amount of rust to form on the surface, which acts later as a 
 slight lubricant and is known as a rust coating, water coating, or 
 sull. 
 
 The last traces of acid are eliminated by treatment in the 
 lime bath (Inning), after which the bundles are taken to the 
 dry house where they are dried (baked) at a low temperature in 
 a furnace called the baker. This treatment expels most of the 
 occluded hydrogen (due to the action of the acid) whose presence 
 causes brittleness (acid brittleness). If the wire is to be bright 
 finished (i.e., unannealed), it is transferred from the rinsing 
 bath immediately to the lime bath. Instead of cleaning wire 
 with acid, it is sometimes put into a scouring barrel, in which it is 
 rotated with some cleaning material. 
 
 The draw plate is either of chilled cast iron or of steel. Accord- 
 ing to Lewis (Iron Trade Review, Oct. 9, 1913) the former is most 
 largely used in this country, and is prepared by reaming out the 
 hole which, when worn, must be enlarged to the next size. The 
 latter, generally used in Europe, is made of the best grade of tool 
 steel (high carbon), and when worn is upset to a smaller size by 
 gently hammering around the hole and then reaming out again to 
 the original size; as this cold upsetting hardens the metal, it is 
 carefully annealed from time to time. Some steel dies are also 
 quenched to contract the hole. The term hole or draw hole 
 (through which the wire passes for reduction) signifies the entire 
 aperture. This is somewhat enlarged at the two surfaces of the 
 plate, and the part of smallest diameter where the drawing is 
 principally accomplished is distinguished as the gage hole. 
 Usually all the holes in one plate are of the same size and the 
 wire is passed through successive plates, each hole serving for one 
 (sometimes two) bundle. After use the plates are annealed (as 
 the metal around the holes has been hardened), the holes reduced 
 
5o8 WIRE 
 
 by hammering and then opened up to the exact size by punching 
 (pricking). The plates used for the first few reductions are 
 sometimes referred to as the roughing blocks, ripping blocks, or 
 rippers, those for the last, as finishing blocks. 
 
 Drawing is performed on the draw bench, which comprises 
 the draw plate and a power reel for pulling the wire through. 
 To start the wire through the hole, it must be pointed either 
 with a small hammer, or by a pair of small rollers with grooves 
 of different sizes, given a rocking movement (like an alligator 
 shears) by an eccentric. The wire is then .pulled through by 
 a pair of tongs (grippers or nippers) attached to a crank shaft, 
 giving a reciprocating (back and forth) movement, until there 
 is a sufficient length to attach it to the power reel. The term 
 ratch is used for the pull of the wire through the die at one opera- 
 tion where a straight pull and not a reel is used. The plate 
 is sometimes tilted backward at a slight angle to kill the wire, 
 i.e., prevent the tendency to spring out into an unmanageably, 
 large coil on removal from the reel. .To reduce the friction in 
 drawing, the wire must be coated with some substance which 
 acts as a lubricant. In dry drawing, grease is employed: it 
 is piled against the back of the draw plate around the hole, 
 and one application serves for a number of reductions. In wet 
 drawing, the wire is given a lees coating by passing it through 
 lees liquor composed of water and some kind of flour, some- 
 times fermented and sometimes mixing with milk of lime. A 
 copper coating (lacquer) is obtained by treating the wire with 
 a weak acidulated solution of copper sulphate, and then usually 
 passing it through lees liquor before drawing. After this treat- 
 ment it is known as lacquered, straw-tinted, or coppered wire; 
 this method is sometimes called the liquor -bright process. If 
 the finished wire is to be coppered, it must receive an additional 
 treatment. 
 
 Multiple drawing is where the wire is drawn through a num- 
 ber of dies simultaneously, being reeled up only after passing 
 through the last, instead of after each plate. In this case, 
 to avoid breaking, it is necessary to provide a power reel between 
 each pair of holes, around which the. wire is given a couple of 
 turns. Passing the wire through the various dies and around 
 the reels, ready for drawing, is called stringing up. After 
 about 8 to 10 holes (hole in this sense means pass or reduction) 
 the wire is so much hardened that it must be reannealed, etc., 
 before drawing can be continued. This fine wire is sometimes 
 batted, i.e., beaten with wooden sticks while being washed after 
 pickling. 
 
 Plain drawn wire (bench hardened wire) is wire in the con- 
 dition in which it leaves the last hole, without any further 
 treatment. Plain annealed wire is where it is annealed in 
 closed iron pots to rended it soft and pliable. Galvanized wire 
 is annealed and then coated with zinc (spelter). In galvanizing, 
 the wire is passed (a) through a lead bath to anneal it; (b) through 
 a weak pickling solution to remove the scale formed; (c) through 
 a rinsing bath; and (d) through the molten spelter contained in the 
 
WIRE WIRE GLASS 509 
 
 galvanizing pan. The excess of zinc is removed by drawing it 
 through plugs of asbestos, called wipers. The wire is kept below 
 the surface of the zinc by passing it under heavy toothed bars, 
 called sinkers. In modern practice a number of wires or strands 
 are treated simultaneously, the whole series of operations being 
 continuous, and one power reel serving to pull each strand 
 through (Bedspn's continuous galvanizing process). Bright 
 annealed wire is where the annealing is carefully conducted in 
 closed pots to keep surface oxidation at a minimum; attempts 
 have also been made to prevent oxidation entirely by means of a 
 reducing or neutral atmosphere. 
 
 After having been drawn down several numbers, i.e., reduced 
 by passing through several successively smaller holes, the wire 
 becomes brittle from the cold working and to permit of further 
 reduction is given a process annealing or works annealing ; this 
 consists in heating to a temperature, which may be below the 
 critical, say 1100 F. (595 C.), and holding a certain length of 
 time (Tinsley) followed by slow cooling. Dead soft annealing, 
 as the name indicates, is where extra precautions are observed 
 to make the wire specially soft for subsequent severe bending or 
 cold working processes. Improved or patented wire is where 
 medium carbon wire (about 0.35 to 0.85% carbon) is heated 
 above the critical point and cooled rapidly through the critical 
 range, the operation usually being continuous, the wire passing 
 through the heated tubes of a furnace and cooled by being 
 brought into the air or into a bath of molten lead, comparatively 
 cool but seldom below 700 F. (370 C.). Patenting serves to 
 increase the ductility and permit of greater subsequent drawing 
 down than is the case with annealing. Higher carbon wire 
 (say 0.65 to i % carbon) is usually treated by quenching and 
 tempering (Tinsley, Am. I. & S. Inst., 1914). 
 
 Tinman's wire is a soft bright drawn wire used in the manufac- 
 ture of various tin plate goods. Plow steel wire is made from a 
 fine grade of high-carbon, crucible steel, and is so called because 
 it was originally used for dragging steam plows. Gun screw wire 
 is a name sometimes employed for wire made from a high grade 
 of refined wrought iron. B., B. B., E. B. B. (best, best best, extra 
 best best) wire, or four-sided charcoal wire were grades in 
 England, used for telegraphic work, made of fagots composed 
 of puddled billetsin the center, and four flats outside, of (a) 
 best best puddled iron, (b) or top and bottom of charcoal iron 
 with sides of best best puddled iron or (c) charcoal iron all 
 around, respectively. Bimetallic wire is usually a combination of 
 steel center with copper outside ("copper clad" see Protection, 
 page 372). Stranded wire is another name for wire rope or cable. 
 
 Wire Drawing. See page 64. 
 
 Wire-edged. Usually a defect; of material having a rough" un- 
 trimmed edge. 
 
 Wire Gage. See page 188. 
 
 Wire Glass. Also called armored glass ; sheets of glass cast around 
 a wire netting which holds the glass 'together in case it becomes 
 cracked or broken. 
 
510 WIRE IRON WORK OF DEFORMATION 
 
 Wire ton. See page 378. 
 
 Wire Rod. See page 507. 
 
 Wire Rod Mill. See page 417. 
 
 Witherow Converter. See page 25. 
 
 Wittgenstein Mill. See page 434. 
 
 Wittnufftt Converter. See page 25. 
 
 Wittorff's Equilibrium Diagram. See page 272. 
 
 Wobble ; Wobbler. See page 407. 
 
 Wb'hler's Law. See page 333. 
 
 Wohler Range; Test. See page 482. 
 
 Wolf Furnace ; Oven. See page 147. 
 
 Wolframinium. A trade name for a special alloy of aluminum 
 
 containing a small percentage of tungsten. 
 Wolfram Steels. See page 450. 
 Wolframite. See page 245. 
 Wood. As a fuel, this is used in metallurgy practically only 
 
 for drying purposes. It consists naturally of nearly equal 
 
 parts of cellulose and water. A sample of air-dried wood 
 
 showed : 
 
 Carbon 40.0% 
 
 Hydrogen 4.8 
 
 Oxygen 32.8 
 
 Nitrogen 0.8 
 
 Ash -. 1.6 
 
 Moisture 20.0 
 
 Wood Coal (Eng.). An old name for charcoal. 
 
 Wood Process. See page 369. 
 
 Wootz. Or Indian steel ; it is manufactured from wrought iron 
 made in a native furnace (India) in the following way (Harbord 
 and Hall): "Small crucibles of refractory clay are used, in 
 each of which about a pound of metal is placed, with a certain 
 proportion of finely chopped wood. The crucibles are then 
 covered with one or two green leaves and wetted clay, and 
 placed in the sun to dry. When the plugs have hardened, 
 twenty to twenty-four of the crucibles are built in an arched 
 form, on the bottom of a small blast furnace, blown by bellows, 
 and strongly heated for two or three hours. The furnace is 
 then allowed to cool, the crucibles taken out and broken, the 
 steel having melted down to a rounded button at the bottom 
 of each pot. Probably in order that it may be completely 
 melted the steel is overcarburized, and before drawing out 
 into bars the buttons are heated for several hours in a charcoal 
 fire, urged by bellows, to a temperature not much below their 
 melting point, and turned over before the blast, so that the 
 metal may be partially decarburized." 
 
 Work. The mechanical treatment which a piece receives in the 
 process of manufacture. 
 
 Work Cold. Of a blast furnace: see page 35. 
 
 Work of Deformation. See page 481. 
 
WORK HARDNESS WUTH PROCESS 511 
 
 Work Hardness. See page 331. 
 
 Work the Holes. To have charge of a crucible furnace. 
 
 Work Hot. Of a blast furnace: see page 35. 
 
 Working. (i) The condition of an operation or process, e.g., 
 "How is the heat working?"; (2) to stir an open hearth heat with 
 a rod, or to add ore, to assist in the oxidation of the carbon and 
 impurities; (3) to corrode, as when a heat is working on the bottom 
 or lining of a furnace; (4) operating a mine. 
 
 Working Anvil Block. See Hammer. 
 
 Working Load ; Strength. See page 468. 
 
 Wring Fit. Of a bar, etc.; which fits a coupling or other piece so 
 accurately that, while it cannot be readily slid or pushed on, it 
 can be wrung or twisted on (Howe). 
 
 Works Annealing. See page 509. 
 
 Wrought Iron. Also called malleable iron in England; iron 
 low in carbon produced in a pasty condition (owing to the 
 temperature employed being too low to render it fluid), in 
 consequence of which a small percentage of slag is mechanically 
 intermingled with it. The percentage of carbon is usually 
 under 0.15%, and that of the other constituents (not including 
 the slag) under 0.25%. It can be forged or rolled, and welded, 
 but is not appreciably hardened by rapid cooling (quenching). 
 It is made by the puddling, a direct, or a charcoal hearth process. 
 
 Wrought Steel. (i) Wrought iron containing sufficient carbon 
 so it may be hardened by quenching; (2) rarely, steel which 
 has been worked, more especially hammered. 
 
 Wulf Oven. See page 147. 
 
 Wiirtemberger Process. See page 319. 
 
 Wuth Process. See page 319. 
 
X 
 
 Xe. Chemical symbol for xenon: see page 84. 
 
 X Band. See page 127. 
 
 X-Ray Examination. Of metals: see page 285. 
 
 Xble ; Xible. An abbreviation sometimes used for crucible. 
 
 512 
 
Yb. Chemical symbol for ytterbium: see page 84. 
 
 Yt. Chemical symbol for yttrium: see page 84. 
 
 Yarrow Test. See page 482. 
 
 Yates Process. See page 148. 
 
 Yatsevitch's Reagent. For etching: see page 287. 
 
 Yellow Prussiate of Potash. Commercial potassium ferrocyanide, 
 
 K 2 Fe(CN) 4 . 
 
 Yellow Pyrites. See page 245. 
 Yellow Temper. Oxide color: see page 230. 
 Yield Point. (i) General: see pages 334 and 470; (2) by scribe or 
 
 scriber method: see page 470. 
 Yield Stress. See page 471. 
 Yielding Guard. See page 415. 
 Young Blowing. In Bessemer practice: see page 21. 
 Young Iron. See page 376. 
 Young's Modulus. see page 334. 
 
 33 513 
 
Zn. Chemical symbol for zinc, q.v. 
 
 Zr. Chemical symbol for Zirconium: see page 84. 
 
 Zenzes Converter. See page 25. 
 
 Zerener Process. See page 503. 
 
 Zero Calorie. See page 199. 
 
 Zero Point. See Curve. 
 
 Zinc. Zn; at. wt., 65.5; melt, pt., 420 C. (786 F.); boil, pt., 
 918 C. (1684 F.); sp. gr., 7.14. It is rarely if ever found in 
 the uncombined condition. When pure it is a crystalline, 
 bluish white metal, only slightly tarnished on exposure to 
 air, and, for this reason, used as a protective coating, the proc- 
 ess being known as galvanizing (see pages 370, 431). It alloys 
 with iron in all proportions, but is rarely found in iron except 
 as an impurity. Cadmia, also called philosopher's wool, is a 
 deposit of oxide of zinc found in the upper part of a blast furnace 
 in which ores containing traces of zinc are smelted. 
 
 Zinc Ashes. The oxidized zinc removed from the surface of a 
 galvanizing bath. 
 
 Zinc Dust. Oxide of zinc produced when zinc is distilled; used 
 in sherardizing: see page 371. 
 
 Zinc Etching. See page 287. 
 
 Zinc Plating. See page 390. 
 
 Zinceisen. Zinc (from a galvanizing bath) of inferior quality, due 
 to the presence of iron. 
 
 Zincing (rare). Zinc plating or galvanizing: see page 370. 
 
 Zone. (i) In cementing: see page 68; (2) of carbon deposition in 
 blast furnace practice: see page 36; (3) of complete fusion: see 
 page 36; (4) of heat interception: see page 36; (5) of incipient 
 fusion: see page 36; (6) of slag formation: see page 36. 
 
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