Civil IjJ 
 
 
 Engineering 
 Library 
 
UNIVERSITY OF CALIFORNIA 
 
 DEPARTMENT OF CIVIL ENGINEERING 
 
 BERKELEY, CALIFORNIA 
 
ELECTRIC WELDING 
 
ELECTRIC WELDING 
 
 BY 
 
 ETHAN VIALL 
 
 EDITOR AMERICAN MACHINIST 
 
 Member American Society of Mechanical Engineers, Society of Automotive Engineers, 
 
 American Institute of Electrical Engineers, Franklin Institute, American Welding 
 
 Society. Author of Manufacture of Artillery Ammunition, United States 
 
 Artillery Ammunition, United States Rifles and Machine Guns, 
 
 Broaches and Broaching, Gas-Torch and Thermit Welding. 
 
 FIRST EDITION 
 THIRD IMPRESSION 
 
 McGRAW-HILL BOOK COMPANY, INC. 
 
 NEW YORK: 370 SEVENTH AVENUE 
 
 LONDON: 6 & 8 BOUVERIE ST., E. C. 4 
 
 1921 
 
.1 A 
 
 Engineering 
 Library 
 
 l^U l^jf^^ 
 
 COPYRIGHT, 1921, BY THE 
 McGRAW-HILL BOOK COMPANY, INC 
 
 PRINTED IN THE UNITED STATES OF AMERICA 
 
PREFACE 
 
 Few fields afford a greater opportunity for study to the 
 mechanic, the student, or the engineer, than that of electric 
 welding. Arc welding, with its practical, every-day, shop appli- 
 cations for repair and manufacture, is in some respects crowding 
 closely into the field in which the gas-torch has seemed supreme. 
 With the development of mechanical devices for the control of 
 the arc, the range of application to production work has greatly 
 increased. 
 
 Resistance welding presents in its various branches some of 
 the most interesting scientific and mechanical problems to be 
 found anywhere. Spot-welding butt-welding line-welding 
 all occupy a particular place in our manufacturing plants today, 
 and new uses are being constantly found. 
 
 In the gathering and arranging of the material used in this 
 book, particular care has been taken to classify and place various 
 subjects together as far as possible. This is not only convenient 
 for reference purposes, but enables the reader to easily compare 
 different makes and types of apparatus. In most cases, the 
 name of the maker of each piece of apparatus is mentioned 
 in the description in order to save the time of those seeking 
 information. 
 
 No time or pains have been spared in the endeavor to make 
 this the most comprehensive book on electric welding equipment 
 and practice, ever published. Every possible source of informa- 
 tion known to the long-experienced editor has been drawn upon 
 and properly credited. 
 
 It is hoped that this book will prove a permanent record of 
 electric welding as it is today, and also be an inspiration and 
 source of information for those engaged in practice, research 
 or development. 
 
 ETHAN VIALL. 
 
 New York City, 
 November, 1920. 
 
 742296 
 
CONTENTS 
 
 PAGE 
 
 PREFACE v 
 
 CHAPTER I 
 
 ELECTRIC WELDING HISTORICAL 1- 8 
 
 The Two Classes of Electric Welding The Zerner, the Ber- 
 nardos, the Slavianoff, the Strohmenger-Slaughter and the 
 LaGrange-Hoho Processes Early Methods of Connecting for 
 Arc Welding Early Resistance Welding Apparatus First 
 Practical Butt-Welding Device DeBenardo Spot-Welds The 
 Kleinschmidt Apparatus Bouchayer 's Machine Principle of 
 the Harmatta Patent The Taylor Cross-Current Spot-Welding 
 Method. 
 
 CHAPTER II 
 
 ARC WELDING EQUIPMENT 9- 27 
 
 What Electric Arc-Welding Is Uses of B.C. and A.C. 
 Schematic Layout for an Arc- Welding Outfit Carbon Electrode 
 Process Metallic Electrode Process Selection of Electrodes 
 Relation of Approximate Arc Currents and Electrode Diam- 
 eters Approximate Current Values for Plates of Different 
 Thickness Illustrations of the Difference Between the Carbon 
 and the Metallic Arc Methods Electrode Holders Sizes 'of 
 Cable for Current Face Masks Selecting a Welding Outfit 
 Eye Protection in Iron Welding Operations The Dangerous 
 Rays Properties of Various Kinds of Glass. 
 
 CHAPTER III 
 
 DIFFERENT MAKES OF ARC WELDING SETS 28- 46 
 
 General Electric Compound- Wound Balancer-Type Arc Weld- 
 ing Set The Welding Control Panel Connections for G.E. 
 Welding Set Data for Metallic-Electrode Arc Butt- and Lap- 
 Welds Carbon-Electrode Cutting Speeds The Wilson Plastic- 
 Arc Set Panel for Wilson Welding and Cutting Set Wilson 
 Portable Outfit The Lincoln Outfit Westinghouse Single- 
 
 vii 
 
viii CONTENTS 
 
 PAGE 
 
 Operator Outfit The U.S. Outfit The "Zeus" Outfit The 
 Arcwell Outfit Alternating-Current Arc-Welding Apparatus 
 G.E. Lead Burning Transformer. 
 
 CHAPTER IV 
 
 TRAINING ARC WELDERS 47- 65 
 
 Use of Helmets and Shields The Welding Booth Welding 
 Systems The Electrode Holder Arc Manipulation Arc 
 Formation Fusion of Electrodes Maintenance of Arc 
 Control of Arc Travel Weaving Arc and Fusion Character- 
 istics Polarity Length of Arc Stability Overlap and 
 Penetration Heat Conductivity and Capacity Expansion and 
 Contraction of Parent Metal Contraction of Deposited 
 Metal Welding Procedure Electrode Current Density In- 
 spection Terminology. 
 
 CHAPTER V 
 CARBON-ELECTRODE ARC WELDING AND CUTTING 66- 80 
 
 Currents Used with Carbon Arc Carbon and Graphite Elec- 
 trodes Shapes and Size of Electrodes Filler Material 
 Proper Welding Position Arc Manipulation Characteristics 
 of the Arc Polarity Arc Length Building up Surfaces 
 Fused Ends of Filler Rods Flanged Seam Welding Weld- 
 ing Non-Ferrous Metals Applications of Carbon-Arc Weld- 
 ing Cutting Data on Cutting Steel Plates Cutting Cast- 
 iron Plates Cutting Cast-Iron Blocks. 
 
 CHAPTER VI 
 ARC WELDING PROCEDURE 81-108 
 
 Resume of Welding Instructions Filling Sequence Welding 
 Two Plates The Back-Step Method Welding a Square 
 Patch Quasi-Arc Welding Typical Examples of Arc Weld- 
 ing Examples of Tube Work Locomotive Work Welding 
 Calculations Strength of Welds Stresses in Joints Inspec- 
 tion of Metallic-Electrode Arc- Welds Good and Bad Welds- 
 Electrode Diameters for Steel Plate Variation in Weld 
 Strength with Change in Arc Current Effects of Short and 
 Long Arcs Heat Treatment Effects of the Chemical Com- 
 position of Electrodes Physical Characteristics of Plates 
 Chemical Analysis of Specimens The Welding Committees 
 Electrodes. 
 
CONTENTS ix 
 
 CHAPTER VII 
 
 PAGE 
 
 ARC WELDING TERMS AND SYMBOLS 109-126 
 
 Definitions of Strap, Butt, Lap, Fillet, Plug and Tee Welds 
 The Single V, Double V, Straight, Single Bevel, Double Bevel, 
 Flat, Horizontal, Vertical and Overhead Weld Tack, Caulking, 
 Strength, Composite, Reinforced, Flush and Concave Welds 
 Symbols for Various Kinds of Welds. 
 
 CHAPTER VIII 
 
 EXAMPLES OF ARC-WELDING JOBS 127-170 
 
 Work on the German Ships Seventy Cylinders Saved Without 
 Replacement The Broken Cylinders of the George Washing- 
 ton Cylinders of the Pocahontas General Ship Work 
 Locomotive Work Repair on a Locomotive Frame Built-Up 
 Pedestal Jaw Repaired Drive Wheel Flue and Firebox 
 Work Side Frames and Couplers Amount Saved by Weld- 
 ing Training of Welders Welded Rails and Cross-Overs 
 Built-Up Rolling Mill Pods Repaired Mill Housing Welded 
 Blow-Holes in Pulley Method of Removing Broken Taps 
 Electric Car Equipment Maintenance A Large Crankshaft 
 Repair Welding High-Speed Tips onto Mild Steel Shanks 
 An All- Welded Mill Building Speed of Arc Welding. 
 
 CHAPTER IX 
 
 PHYSICAL PROPERTIES OF ARC-FUSED STEEL 171-190 
 
 Preliminary Examinations of Arc Welds Method of Prepar- 
 ing Test Specimens Arrangement of the Welding Apparatus 
 The ' ' Paste ' ' Used for Coated Electrodes Composition of Elec- 
 trodes Before and After Fusing Relation Between Nitrogen- 
 Content and Current Density Appearance of Specimens After 
 Test Tensile Properties of Electrodes Results of Tests on 
 Fifty Specimens Mechanical Properties of the Are-Fused 
 Metal Dependence of Physical Properties on Soundness 
 Macrostructure Discussion of the Results of the Tests Com- 
 parison of the Bureau of Standards and the Wirt-Jones Tests. 
 
 CHAPTER X 
 
 METALLOGRAPHY OF ARC-FUSED STEEL 191-213 
 
 General Features of the Microstructure of the Electrodes 
 Used Microscopic Evidence of Unsoundness Characteristic 
 "Needles" or "Plates" Plates Probably due to Nitrates 
 
X CONTENTS 
 
 PAGE 
 
 Relation of Microstructure to the Path of Rupture Effect of 
 Heat Treatment Upon Structure Persistence of "Plates" 
 After Annealing Thermal Analysis of Arc-Fused Steel 
 Summary. 
 
 CHAPTER XI 
 
 AUTOMATIC ARC WELDING 214-238 
 
 The General Electric Automatic Arc Welding Machine The 
 Welding Head Set-Up for Circular Welding Set-Up for 
 Building Up a Shaft Diagram of Control of Feed Motor- 
 Some Work Done by the Machine Repaired Crane Wheels 
 Welded Hub Stampings Welded Rear Axle Housings Welded 
 Tank Seam The Morton Semi-Automatic Machine Methods 
 of Mechanically Stabilizing and Controlling the Arc Examples 
 of Work Done by the Morton Machine The G.E. Electric- Arc 
 Seam Welding Machine. 
 
 CHAPTER XII 
 
 BUTT-WELDING MACHINES AND WORK 239-275 
 
 Resistance Welding Machines Butt-Welding Machines Cur- 
 rent Used in Butt-Welding How the Secondary Windings of 
 the Transformer are Connected Typical Butt- Welding Ma- 
 chine with Main Parts Named How the Clamping Jaws are 
 Operated Annealing Welds Portable Wire Welding Ma- 
 chines Examples of Butt-Welding Jobs Welding Copper and 
 Brass Rod Welding Aluminum Typical Copper Welds 
 T-Welding Welding Band Saws Automobile Rim Welding 
 The " Flash- Weld "Welding Heavy Truck Rims Welding 
 Pipe The Type of Clamp Used for Pipe The Approximate 
 Current Used for Pipe Welding The Winfield Butt-Welding 
 Machines Cost of Butt- Welds The Federal Butt-Welding 
 Machines Welding Motor Bars to the End Rings Welding 
 Valve Elbows on Liberty Motor Cylinders An Automatic 
 Chain-Making Machine Electro-Percussive Welding How the 
 Machine is Made Uses of Percussive Welding Power Con- 
 sumed and Time to Make a Percussive Weld. 
 
 CHAPTER XIII 
 
 SPOT- WELDING MACHINES AND WORK 276-323 
 
 Spot'- Welding Three Desirable Welding Conditions Welding 
 Galvanized Iron and Other Metals Mash Welding Details of 
 Standard Spot-Welding Machines Foot-, Automatic-, and 
 
CONTENTS xi 
 
 PAGE 
 
 Hand-Operated Machines Examples of Spot-Welding Work 
 Form and Sizes of Die-Points for Spot-Welding The Win- 
 field Spot-Welding Machines Machine for Welding Auto- 
 mobile Bodies The Federal Spot-Welding Machines The 
 Federal Water-Cooled Die-Points Rotatable Head Two-Spot 
 Welding Machine Automatic Machine for Welding Channels 
 Automatic Pulley Welding Machine The Taylor Cross-Cur- 
 rent, Spot-Welding Machines Automatic Hog-Ring Machine 
 A Space-Block Welding Machine Combination Spot- and 
 Line-Welding Machines Spot-Welding Machines for Ship 
 Work A Large Portable Spot-Welding Machine Duplex 
 Welding Machine A Powerful Experimental Machine 
 Portable Mash- Welding Machine for Square or Round Rods 
 Cost of Spot Welding. 
 
 CHAPTER XIV 
 
 WELDING BOILER TUBES BY THE ELECTRIC RESISTANCE PROCESS. . . . 324-342 
 
 How Boiler Flues are Held for Welding How the Tube 
 Ends are Prepared Scarf- Weld Straight Butt-WeldFlash 
 Weld Use of a Flux How the Work is Placed in the Jaws 
 to Heat Evenly Electric and Oil Heating Compared Kind 
 of Machine to Use Flash Welding Welding in the Topeka 
 Shops of the Santa Fe Railroad The Way the Work Heats 
 Up The Final Rolling. 
 
 CHAPTER XV 
 
 ELECTRIC WELDING OF HIGH-SPEED STEEL AND STELLITE IN TOOL 
 MANUFACTURE 343-364 
 
 The Machines Used to Weld Tools Welding High-Speed to 
 Low-Carbon Steel Examples of Welded Tools Jaws for 
 Special Work How the Parts are Arranged for Welding 
 Clamping in the Jaws Insert Welding Jaws for Stellite 
 Welding Jaws for Stellite Insert Welding The Vertical Type 
 of Welding Machine Making a ' ' Mash-Weld ' ' Jaws for 
 Mash-Welding Grooving the Pieces to be Welded Current 
 Consumption for Various Jobs Sizes of Wire to Use. 
 
 CHAPTER XVI 
 
 ELECTRIC SEAM WELDING 365-381 
 
 The Process of Seam Welding Kind of Machine Used De- 
 tails of the Roller Head Thomson Lap-Seam Welding Ma- 
 chine Welding Oil Stove Burner Tubes Jig for Welding 
 
xii CONTENTS 
 
 PAGE 
 
 Automobile Muffler Tubes Jig for Welding Large Can 
 Seams Jig for Welding Bucket Bodies Jig for Welding 
 Ends of Metal Strips Together Flange Seam Welding Jig 
 for Welding Teapot Spouts Approximate Current for Six- 
 Inch Seam for Various Thicknesses of Sheet Metal Size of 
 Wire to Use in Connecting up a Welding Machine. 
 
 CHAPTER XVII 
 
 MAKING PROPER RATES FOR ELECTRIC WELDING, AND THE STRENGTH 
 OF WELDS 382-399 
 
 Reasons for Misunderstanding Between User and Producer 
 The Metering Proposition Energy Consumption of Resistance 
 Welding for Commercial Grades of Sheet Iron Effect of 
 Clamping Distance Between Electrodes Upon Time and Energy 
 Demand The Load Factor Maximum Demand Power 
 Factor Strength of Combination Spot and Arc Welds Spot 
 Welding Tests on Hoop Iron Strength of Spot-Welded 
 Holes Plates Plugged by Welding Tested Plates Tensile 
 Tests of Plates Plugged by Spot-Welding Strength of Mash- 
 Welded Rods Strength of Resistance Butt-Welds Elementary 
 Electric Information What is a Volt? What is an Ampere? 
 What is a Kilowatt? What is Kva? 
 
ELECTRIC WELDING 
 
 CHAPTER I 
 ELECTRIC WELDING HISTORICAL 
 
 All electric welding may be divided into two general classes 
 arc welding and resistance welding. In each class there are 
 a number of ways of obtaining the desired results. Arc welding 
 is the older process, and appears to have been first used by de 
 Meritens in 1881 for uniting parts of storage batteries. He 
 connected the work to the positive pole of a current supply 
 capable of maintaining an arc. The other pole was connected 
 to a carbon rod. An arc was struck by touching the carbon 
 rod to the work and withdrawing it slightly. The heat generated 
 fused the metal parts together, the arc being applied in a way 
 similar to that of the flame of the modern gas torch. 
 
 Of the several methods of arc welding, there are the Zerner, 
 the Bernardos, the Slavianoff and the Strohmenger-Slaughter 
 processes, as well as some modifications of them. The different 
 methods are named after the men generally credited with being 
 responsible for their development. The LaGrange-Hoho process 
 is not a welding process at all, as it is merely a method of heating 
 metal which is then welded by hammering, as in blacksmith 
 work. It is sometimes called the " water-pail forge." 
 
 The Zerner process employs two carbon rods fastened in a 
 holder so that their ends converge like a V, as shown in Fig. 1. 
 An arc is drawn between the converging ends and this arc is 
 caused to impinge on the work by means of a powerful electro- 
 magnet. The flame acts in such a manner that this process is 
 commonly known as the electric blowpipe method. The Zerner 
 process is so complicated and requires so much skill that it is 
 practically useless. A modification of the Zerner process, known 
 
- > %o<, v 
 
 " i O S. 
 
 2 ELECTRIC WELDING 
 
 as t be ; 'voltex process," uses carbon rods containing a small 
 percentage of metallic oxide which is converted into metallic 
 vapor. iThris vapor increases the size of the arc and to some 
 extent prevents the excessive carbonizing of the work. This 
 process, however, is about as impractical for general use as the 
 other. 
 
 The Bernardos process employs a single carbon or graphite 
 
 FlG. 1 The Zerner Electric ' ' Blow-Pipe. : 
 
 rod and the arc is drawn between this rod and the work. A 
 sketch of the original apparatus is shown in Fig. 2. This 
 is commonly called the carbon-electrode process. In using this 
 method it is considered advisable to connect the carbon to the 
 negative side and the work to the positive. This prevents the 
 carbon of the rod from being carried into the metal and a softer 
 weld is produced. 
 
 In the Slavianoff process a metal electrode is used instead 
 
UNIVERSITY OF CALIFORNIA 
 DEPARTMENT OF CIVIL ENGINEERING 
 ELECTRIC WELDIN^H^^%IfA^ AL|FOR(X: , | ^ 
 
 of a carbon. This process is known as the metallic-electrode 
 process. 
 
 The Strohmenger-Slaughter, or covered electrode, process 
 is similar to the Slavianoff except that a coated metallic elec- 
 
 "<<(fffff'///^///&//&/S/////////////////////////W 
 
 FIG. 2. Original Bernardos Carbon Electrode Apparatus. 
 
 Grid 
 Rheostat 
 
 Circuit 
 Breaker, 
 
 FIG. 3. Arc Welding Circuits as First Used. 
 
 trode is used. In this process either direct or alternating cur- 
 rent may be used. 
 
 Some of the early methods of connecting up for arc welding 
 are shown in Fig. 3. 
 
 The LaGrange-Hoho heating process makes use of a wooden 
 tank filled with some electrolyte, such as a solution of sodium 
 
ELECTRIC WELDING 
 
 or potassium carbonate. A plate connected to the positive wire 
 is immersed in the liquid and the work to be heated is connected 
 to the negative wire. The work is then immersed in the liquid. 
 When the piece has reached a welding temperature it is removed 
 and the weld performed by means of a hammer and anvil 
 
 Resistance Welding. The idea of joining metals by means 
 of an electric current, known as the resistance or incandescent 
 process, was conceived by Elihu Thomson some time in 1877. 
 
 JMMA/^^ 
 
 FIG. 4. First Practical Electric Butt Welding Device, Patented 
 by Elihu Thomson, Aug. 10, 1886. 
 
 Little was done with the idea from a practical standpoint for 
 several years. Between 1883 and 1885 he developed and built 
 an experimental machine. A larger machine was built in 1886. 
 He obtained his first patent on a device for electric welding 
 Aug. 10, 1886. The general outline of this first device is shown 
 in Fig. 4. The first experiments were mostly confined to what 
 is now known as butt welding, and it was soon found that the 
 jaws used to hold the parts heated excessively. To remedy this 
 water-cooled clamping jaws were developed. 
 
ELECTRIC WELDING HISTORICAL 
 
 5 
 
 FIG. 5. Plates "Spot Welded" by Carbon Arc. 
 
 FIG. 6. The DeBenardo Carbon Electrode Spot Welding Apparatus. 
 
 FlG. 7. The Kleinschmidt Apparatus, Using Copper Electrodes. 
 
6 ELECTRIC WELDING 
 
 Closely following the butt welding came other applications 
 of the resistance process, such as spot, point or projection, ridge 
 and seam welding. Percussive welding, which is a form of 
 resistance welding, was developed about 1905. Since spot weld- 
 ing is such an important factor in the manufacturing field today 
 
 FIG. 8. Bouchayer's Spot Welding Machine, Using Duplex Copper 
 
 Electrodes. 
 
 the evolution of this process, as indicated by the more prominent 
 patents, will be of considerable interest: Fig 5 shows plates spot 
 welded together by means of the carbon arc. This was patented 
 by DeBenardo, May 17, 1887, Pat. No. 363,320. The claims 
 cover a weld made at points only. The darkened places indicate 
 
ELECTRIC WELDING HISTORICAL 7 
 
 where the welds were made. Fig. 6 shows the apparatus made 
 by DeBenardo for making "spot welds," as they are known 
 today. He patented this in Germany, Jan. 21, 1888. Carbon 
 electrodes were used. This patent was probably the first to 
 cover the process of welding under pressure and also for passing 
 the current through the sheets being welded. The German patent 
 number was 46,776 49. 
 
 The apparatus shown in Fig. 7 is known as the Kleinschmidt 
 patent, No. 616,463, issued Dec. 20, 1898. The patent claims 
 cover the first use of pointed copper electrodes and raised sec- 
 tions, or projections, on the work in order to localize the flow 
 of the current at the point where the weld was to be effected. 
 
 \L 
 
 FIG. 9. Principle of the Harmatta Process, Using Copper Electrodes. 
 
 Considerable pressure was also applied to the electrodes and 
 work by mechanical means. 
 
 Fig. 8 shows diagrammatically Bouchayer's spot welding 
 machine, patented in France, March 13, 1903, No. 330,200. He 
 used two transformers, one on each side of the work. Duplex 
 copper electrodes were used, and if the transformers were con- 
 nected parallel one spot weld would be made at each operation. 
 If the transformers were connected in series two spot welds 
 would be made. 
 
 Fig. 9 illustrates the principle of the Harmatta patent, No. 
 1,046,066, issued Dec. 3, 1912. This is practically the same as 
 the DeBenardo patent, No. 46,776 49, except that copper elec- 
 
8 
 
 ELECTRIC WELDING 
 
 trodes are used. However, it is under the Harmatta patent that 
 a majority of the spot welding machines in use today are made. 
 Fig. 10 illustrates the principle on which the Taylor patent 
 is founded. This patent was issued Oct. 16, 1917, No. 1,243,004. 
 It covers the use of two currents which are caused to cross the 
 path of each other in a diagonal direction, concentrating the 
 heating effects at the place of intersection. 
 
 a 
 
 S 
 
 b 
 
 7 
 
 
 FIG. 10. The Taylor Cross-Current Spot Welding Method. 
 
 From the foregoing it will be seen that spot welds, as this 
 term is now understood, can be produced in a number of ways, 
 none of which methods are identical. As a matter of fact, spot 
 welds can be produced by means of the gas torch or by the 
 blacksmith forge and anvil, although these methods would not 
 be economical. 
 
CHAPTER II 
 ARC WELDING EQUIPMENT 
 
 Electric Arc Welding is the transformation of electrical 
 energy into heat through the medium of an arc for the purpose 
 of melting and fusing together two metals, allowing them to 
 melt, unite, and then cool. The fusion is accomplished entirely 
 without pressure. The heat is produced by the passage of an 
 electric current from one conductor to another through air which 
 is a poor conductor of electricity, and offers a high resistance 
 to its passage. The heat of the arc is the hottest flame that is 
 obtainable, having a temperature estimated to be between 
 3,500 and 4,000 deg. C. (6,332 to 7,232 deg. P.). 
 
 The metal to be welded is made one terminal of the circuit, 
 the other terminal being the electrode. By bringing the elec- 
 trode into contact with the metal and instantly withdrawing it 
 a short distance, an arc is established between the two. Through 
 the medium of the heat thus produced, metal may be entirely 
 melted away or cut, added to or built up, or fused to another 
 piece of metal as desired. A particularly advantageous feature 
 of the electric arc weld is afforded through the concentration 
 of this intense heat in a small area, enabling it to be applied 
 just where it is needed. 
 
 Direct-current is now more generally used for arc welding 
 than alternating-current. 
 
 When using direct-current, the metal to be welded is made 
 the positive terminal of the circuit, and the electrode is made the 
 negative terminal. 
 
 Regarding alternating-current it is obvious that an equal 
 amount of heat will be developed at the work and at the elec- 
 trode, while with direct-current welding we have considerably 
 more heat developed at the positive terminal. Also in arc weld- 
 ing the negative electrode determines the character of the arc, 
 which permits of making additions to the weld in a way that is 
 
 9 
 
10 
 
 ELECTRIC WELDING 
 
 not possible with alternating-current. Inasmuch as the work 
 always has considerably greater heat-absorbing capacity than the 
 electrode, it would seem only reasonable that the direct-current 
 arc is inherently better suited for this work. 
 
 Two systems of electric arc welding, based on the type of 
 electrode employed, are in general use, known as the carbon (or 
 graphite) and the metallic electrode processes. The latter 
 
 Circuit 
 Breaker 
 
 rrn 
 
 Grief 
 Resistors 
 
 Electrode 
 
 Courtesy of the Westinghouse Co. 
 FIG. 11. Simple Schematic Welding Circuit. 
 
 process is also sub-divided into those using the bare and the 
 covered metallic electrodes. 
 
 A simple schematic layout for an arc-welding outfit is shown 
 in Fig. 11. 
 
 The Carbon Electrode Process. In this process, the nega- 
 tive terminal or electrode is a carbon pencil from 6 to 12 in. 
 in length and from J to 1 in. in diameter. This was the original 
 process devised by Bernardos and has been in more or less general 
 
ARC WELDING EQUIPMENT 11 
 
 use for more than thirty years. The metal is made the positive 
 terminal as in the metallic electrode process in order that the 
 greater heat developed in this terminal may be applied just 
 where it is needed. Also, if the carbon were positive, the tendency 
 would be for the carbon particles to flow into the weld and 
 thereby make it hard and more difficult to machine. 
 
 The current used in this process is usually between 300 and 
 450 amp. For some special applications as high as from 600 
 to 800 may be required, especially if considerable speed is desired. 
 The arc supplies the heat and the filler metal must be fed into 
 the weld by hand from a metallic bar. 
 
 The class of work to which the carbon process may be applied 
 includes cutting or melting of metals, repairing broken parts 
 and building up materials, but it is not especially adapted to 
 work where strength is of prime importance unless the operator 
 is trained in the use of the carbon electrode. It is not practical 
 to weld with it overhead or on a vertical surface but there are 
 many classes of work which can be profitably done by this process. 
 It can be used very advantageously for improving the finished 
 surface of welds made by metal electrodes. The carbon electrode 
 process is very often useful for cutting cast iron and non-ferrous 
 metals, and for filling up blowholes. 
 
 The Metallic Electrode Process. In the metallic electrode 
 process, a metal rod or pencil is made the negative terminal, 
 and the metal to be welded becomes the positive terminal. 
 
 When the arc is drawn, the metal rod melts at the end and 
 is automatically deposited in a molten state in the hottest portion 
 of the weld surface. Since the filler is carried directly to the 
 weld, this process is particularly well adapted to work on vertical 
 surfaces and to overhead work. 
 
 If the proper length of arc is uniformly maintained on clean 
 work, the voltage across the arc will never greatly exceed 22 
 volts for bare electrodes and 35 volts for coated electrodes. The 
 arc length will vary to a certain degree however, owing to the 
 physical impossibility of an operator being able to hold the elec- 
 trode at an absolutely uniform distance from the metal through- 
 out the time required to make the weld. 
 
 It is very essential that the surfaces be absolutely clean and 
 free from oxides and dirt, as any foreign matter present will 
 materially affect the success of the weld. 
 
12 ELECTRIC WELDING 
 
 When using a metallic electrode, the arc which is formed 
 by withdrawing it from the work, consists of a highly luminous 
 central core of iron vapor surrounded by a flame composed 
 largely of oxide vapors. At the temperature prevailing in the 
 arc stream and at the electrode terminals, chemical combinations 
 occur instantaneously between the vaporized metals and the 
 atmospheric gases. These reactions continue until a flame of 
 incandescent gaseous compounds is formed which completely 
 envelopes the arc core. However, drafts created by the high 
 temperature of the vapors and by local air currents tend to 
 remove this protecting screen as fast as it is formed, making it 
 necessary for the welder to manipulate the electrode so that the 
 maximum protective flame for both arc stream and electrode 
 deposit is continuously secured. This can be obtained auto- 
 matically by the maintenance of a short arc and the proper 
 inclination of the electrode towards the work in order to com- 
 pensate for draft currents. 
 
 Selection of Electrodes. The use of a metallic electrode 
 for arc welding has proved more satisfactory than the use of 
 a carbon or graphite electrode which necessitates feeding the 
 new metal or filler into the arc by means of a rod or wire. The 
 chief reason for this is that, when the metallic electrode process 
 is used, the end of the electrode is melted and the molten metal 
 is carried through the arc to be deposited on the material being 
 welded at the point where the material is in a molten state 
 produce*! by the heat of the arc. Thus a perfect union or fusion 
 is produced with the newly deposited metal. 
 
 Wire for metallic arc welding must be of uniform, homogene- 
 ous structure, free from segregation, oxides, pipes, seams, etc. 
 The commercial weldability of electrodes should be determined 
 by means of tests performed by an experienced operator, who 
 can ascertain whether the wire flows smoothly and evenly through 
 the arc without any detrimental phenomena. 
 
 The following table indicates the maximum range of the 
 chemical composition of bare electrodes for welding mild steel: 
 
 Carbon trace up to 0.25% 
 
 Manganese trace up to 0.99% 
 
 Phosphorous not to exceed 0.05% 
 
 Sulphur not to exceed 0.05% 
 
 Silicon not to exceed 0.08% 
 
ARC WELDING EQUIPMENT 
 
 13 
 
 The composition of the mild steel electrodes, commonly used, 
 is around 0.18 per cent carbon, and manganese not exceeding 
 0.05 per cent, with only a trace of phosphorus, sulphur and 
 silicon. 
 
 The size, in diameter, ordinarily required will be 1 / 8 in., 5 / 32 
 in., and Vie i n - an <l on ly occasionally the 3 / 32 i n - 
 
 These electrodes are furnished by a number of firms, among 
 whom are John A. Roebling's Sons Co., Trenton, N. J. ; American 
 Rolling Mills Co., Middlctown, Ohio ; American Steel and Wire 
 
 50 
 
 00 
 
 250 
 
 100 150 
 
 Amperes Arc Current 
 
 Courtesy of the Westinghouse Co. 
 
 FIG. 12. Eelation of Approximate Arc Currents and Electrode Diameters. 
 
 Co., Pittsburgh; Ferride Electric Welding Wire Co., New 
 York City ; Page Woven Wire Co., Monessen, Pa. ; John Potts 
 Co., Philadelphia. (M** ) 
 
 A coated electrode is one which has had a coating of some 
 kind applied to its surface for the purpose of totally or partially 
 excluding the atmosphere from the metal while in a molten state 
 when passing through the arc and after it has been deposited. 
 
 The proper size of electrode may be determined from Fig. 
 12 from which it will be seen that the class of work and current 
 used are both factors determining the size of the electrode for 
 
14 ELECTRIC WELDING 
 
 welding steel plates of various i hicknesses. To find the diameter 
 of the metallic electrode required, select, for example, a three- 
 eighths plate, and follow horizontally to the "Thickness of the 
 Plate Curve/' The vertical line through this intersection repre- 
 sents about 110 amp. as the most suitable current to be used 
 with this size of plate. Then follow this vertical line to its 
 intersection with the "Diameter of Electrode" curve which 
 locates a horizontal line representing approximately an electrode 
 5 / 32 in. in diameter. In a similar manner, a V^-in. plate requires 
 about 125 amp. and a 5 / 32 -in. electrode. 
 
 The amount of current to be used is dependent on the thick- 
 ness of the plate to be welded when this value is J in. or less. 
 Average values for welding mild steel plates with direct current 
 are indicated by the curve referred to above in connection with 
 the selection of the electrode of proper size. These data are also 
 shown in Table I. 
 
 TABLE I. APPROXIMATE CURRENT VALUES FOR PLATES OF DIFFERENT 
 
 THICKNESS 
 
 Plate Thickness 
 
 Current 
 
 Electrode Diameter 
 
 in Inches 
 
 in Amperes 
 
 in Inches 
 
 1/16 
 
 20 to 50 
 
 1/16 
 
 1/8 
 
 50 to 85 
 
 3/32 
 
 3/16 
 
 75 to 110 
 
 1/8 
 
 1/4 
 
 90 to 125 
 
 1/8 
 
 3/8 
 
 110 to 150 
 
 5/32 
 
 1/2 
 
 125 to 170 
 
 5/32 
 
 5/8 
 
 140 to 185 
 
 5/32 
 
 3/4 
 
 150 to 200 
 
 3/16 
 
 7/8 
 
 165 to 215 
 
 3/16 
 
 1 
 
 175 to 225 
 
 3/16 
 
 It should be borne in mind, however, that these values are 
 only approximate as the amount of current to be used is 
 dependent on the temperature of the plate and also upon the 
 type of joint. For example, when making a lap weld between 
 two |-in. steel plates at ordinary air temperature of about 
 65 deg. F. it has been found that the extra good results were 
 obtained by using a current of about 225 amp. and a Vie-in 
 diameter electrode. The explanation for the high current per- 
 missible is the tremendous heat storage and dissipation capacity 
 of the lapped plates which makes the combination practically 
 
ARC WELDING EQUIPMENT 
 
 15 
 
 FIG. 13. Carbon-Arc Welding, Using King Mask. 
 
 FlG. 14. Metallic-Arc Welding, Using a Hand Shield. 
 
16 
 
 ELECTRIC WELDING 
 
 equivalent to that of a butt weld of two 1-in. plates. For that 
 reason the above values will be very greatly increased in the 
 case of lap welds which require practically twice the amount 
 of current taken by the butt welds. 
 
 When the proper current value is used there will be a crater, 
 
 FIG. 15. Simple Form of Electrode Holder. 
 
 or depression, formed when the arc is interrupted. This shows 
 that the newly deposited metal is penetrating or "biting into" 
 the work. 
 
 The difference between the carbon and the metallic electrode 
 processes can be seen in Figs. 13 and 14. In Fig. 13 the welder 
 
 FIG. 16. Special Make of Electrode Holder. 
 
 is using a carbon electrode and feeding metal into the weld from 
 a metal rod held in his left hand. In Fig. 14 the metal rod 
 is held in a special holder and not only carries the current but 
 metal from it is deposited on the work. 
 
 Electrode holders should be simple, mechanically strong, and 
 so designed as to hold the electrode firmly. It should be prac- 
 
ARC WELDING EQUIPMENT 17 
 
 tically impossible to burn or damage the holder by accidental 
 contact so that it will not work. Small, flimsy or light projecting 
 parts are almost sure to be broken off or bent. Fig. 15 shows 
 one of these holders that answers the requirements. However, 
 any of the companies selling arc welding apparatus will be able 
 to supply dependable holders. 
 
 A holder made by the Arc Welding Machine Co., New York, 
 is shown in Fig. 16 and in detail in Fig. 17. The metal rod 
 is clamped in by means of an eccentric segment operated by 
 a thumb lever. If the rod should freeze to the work it will not 
 pull out of the holder, but will be gripped all the tighter. The 
 
 FIG. 17. Details of Special Electrode Holder. 
 
 welding current enters at the rear end of the composition shank, 
 passes along the shank to the head of the tool, and from there 
 directly into the electrode. It will be noted that there are no 
 joints in this tool except where the cable is soldered into the 
 shank. There is a relatively large contact surface between the 
 electrode and the holding head, which precludes any possible 
 heating at this point. The trigger is intended for remote control 
 employed with the closed circuit system. Whenever this holder 
 is used on other systems, the trigger is omitted. 
 
 Cable. For arc welding service the cables leading to the 
 electrode holder should be very flexible in order to allow the 
 operator full control of the arc. 
 
 The following sizes of cable have been found by the General 
 
18 
 
 ELECTRIC WELDING 
 
 Electric Co. suitable for this service, due account being taken 
 of the intermittent character of the work. 
 
 It is extra flexible stranded dynamo cable, insulated for 75-v. 
 circuit, with varnished cambric insulation, covered with weather- 
 proof braid. 
 
 Circular Mills 
 90,000 
 
 150,000 
 260,000 
 
 It will be noted in Figs. 13 and 14, that two different ways 
 of protecting the eyes are shown. One man has a helmet and 
 
 Amperes 
 
 Size of Cable 
 
 Up to 200 
 
 225/24 
 
 Over 200 
 Up to 500 
 
 375/24 
 
 Over 500 
 Up to 1,000 
 
 650/24 
 
 FIG. 18. King Face Masks With and Without Side Screens. 
 
 the other uses a shield held in the hand. Conditions under which 
 the welders work, and their personal preferences, largely dictate 
 which type is to be used. However, no welder should ever at- 
 tempt arc welding without a protecting screen fitted with the 
 right kind of glass. Cheap glass is dear at any price, for the 
 light rays thrown off from the arc are very dangerous to the 
 eyesight. The guard should be so made as to not only protect 
 the eyes from dangerous light rays, but should also protect the 
 face and neck from flying sparks of metal. 
 
 A very good face mask made by Julius King Optical Co., 
 New York, is shown in Fig. 18. These masks are made of fiber 
 
ARC WELDING EQUIPMENT 
 
 19 
 
 and provision is made for a free circulation of air between the 
 front and the face, not only keeping the operator cool, but 
 preventing the tendency of the lenses to fog. The masks are 
 supported by bands over the head and it is said that weight 
 
 FIG. 19. King Hand Shields. 
 
 Fie. 20. Method of Using Screens to Protect Others. 
 
 is not apparent and that they are as comfortable to wear as a 
 cap. Two styles are made with and without side screens. The 
 one without screens may be had with combination lenses tinted 
 for acetylene or electric welding or with any other tint for 
 specific work. The one with side screens, providing side vision, 
 
20 
 
 ELECTRIC WELDING 
 
ARC WELDING EQUIPMENT 21 
 
 is fitted either with combination lenses or with Ciear Saniglass 
 lenses. A hand shield is shown in Fig. 19. 
 
 In arc welding in the open, other workmen or onlookers are 
 liable to injury as well as the welders, so screens should be placed 
 around the work to conceal the light rays from the view of 
 others besides the welder. Such an arrangement is shown in 
 Fig. 20. 
 
 Where repetition work is to be done, it is well to provide 
 individual stalls or booths, somewhat similar to the one shown 
 in Fig. 21. These were designed for use in the welding schools 
 under the supervision of the Lincoln Electric Co. For actual 
 shop work, curtains or screens should be provided back of the 
 welders. 
 
 It must be remembered also, that owing to the presence of 
 ultra-violet rays, severe flesh burns may result with some people 
 if proper gloves and clothing are not worn especially when 
 using the carbon arc. 
 
 Selecting a Welding Outfit. Welding outfits may be of the 
 stationary or the portable type. These may also be divided into 
 motor-generator sets and the "transformer" types. Both d.c. 
 and a.c. current may be used primarily, depending on the ap- 
 paratus employed and the source of current available. 
 
 Regarding the selection of any particular outfit J. M. Ham, 
 writing in the General Electric Review for December, 1918, says : 
 
 Few things electrical have in so short a period of time 
 created such wide-spread interest as that of arc welding. En- 
 gineers having to do with steel products, in whatever form 
 produced or in whatever way employed, have investigated its 
 uses not only as a building agent when applied to new material 
 but as a reclaiming agent for worn or broken parts. In both 
 cases its possibilities as a means of greatly increasing output 
 and in saving otherwise useless parts at a small fraction of their 
 original or replacement value has proved astounding. 
 
 Out of these investigations have grown several systems of 
 arc welding. 
 
 To exploit these is the duty of the sales department and the 
 measure of its success depends upon the quality of service 
 rendered. 
 
 The difficulties of giving service are perhaps not fully ap- 
 preciated. Where so many systems have been called for and 
 
22 ELECTRIC WELDING 
 
 where so many individual ideas have to be met, the problems 
 of the manufacturer become multiplied. 
 
 During a period of freight congestion when locomotives were 
 in unprecendented demand, an engine was run into the repair 
 shop with slid flat spots on each of the eight driving wheels, 
 and orders were issued to return it ready for service in record 
 time. In three hours repairs had been completed by means of 
 the electric arc (to have put on new tires would have required 
 three to four days) and the locomotive was out on the road. 
 Many other achievements as remarkable as these have been 
 obtained. 
 
 It would seem that having demonstrated the success of arc 
 welding for a given line of work, others similarly engaged 
 would be keen to take advantage of it ; but that is true only 
 in part, possibly because this is a "show me" age. 
 
 When it becomes apparent to the investigator of arc welding 
 possibilities that the process fulfills his requirements, the ques- 
 tion of what system to employ confronts him; salesmen are on 
 the job to tell bin* about their particular specialties. He is 
 informed that the real secret of welding is having the proper 
 electrode (the salesman's special kind) ; it must be covered or 
 bare, as the case may be, and contain certain unnamed in- 
 gredients. The merits of the direct-current system are extolled. 
 Alternating-current outfits are advocated by others, it being 
 claimed that they bite deeper and weld if the arc is held. The 
 prospective buyer retires with a headache to think it over. 
 
 There is no mystery about arc welding. It is being done 
 with all sorts of outfits and many varieties of electrodes. It 
 can even be done from power lines with resistance in series with 
 the arc. But these systems differ widely in essentials, just as 
 in the case of automobiles. We can buy a cheap car or an 
 expensive car, and in either event we get just about what we 
 pay for. 
 
 The arc-welding set must pay its way. It must earn dividends 
 and conserve materials, and when properly selected and applied 
 does both of these things to a degree quite gratifying. To the 
 discriminating purchaser it is not sufficient merely to know that 
 an outfit will make a weld, he wants to know if it is the best 
 weld that can be made, if it can be made in the shortest possible 
 time, and whether the ratio between cost of the entire system 
 
ARC WELDING EQUIPMENT 23 
 
 to the savings affected is the lowest obtainable. He doubtless 
 will, if the work is of sufficient magnitude to warrant, establish 
 a welding department with a trained arc welding man in charge, 
 and see that this department stands on its own feet. By so doing 
 he places responsibility on a man who knows what to do and 
 how to do it a friend rather than a foe of the system. He 
 will, other things being anything like equal, respect the opinion 
 of the operator in the selection of the system to be employed, 
 because it is better to provide a man with tools he is familiar 
 with and prefers to use, rather than to force him to use some- 
 thing with which he is unfamiliar or which he regards with 
 disfavor. 
 
 Obviously, the purchaser wishes to know that the companies 
 he is dealing with are reliable and responsible, that the experience 
 back of the salesmen is sufficient to warrant faith in his product. 
 It is important to know the amount of power required per 
 operator and whether drawing the needed amount from his own 
 lines or from those of the power company will interfere with 
 the system, and if so to what extent, and what, if any, additional 
 apparatus will be needed to correct the trouble. Having 
 determined these things to his satisfaction, he can install his 
 arc-welding system with a considerable degree of assurance that 
 there will be a decided saving in time, men, and money, and a 
 genuine conservation of materials. 
 
 EYE PROTECTION IN IRON WELDING OPERATIONS 
 
 In the General Electric Review for Dec*, 1918, W. S. Andrews 
 says in part: 
 
 Radiation from an intensely heated solid or vapor may be divided under 
 the three headings: 
 
 (1) Invisible infra-red rays 
 
 (2) Visible light rays 
 
 (3) Invisible ultra-violet rays. 
 
 There is no clear line of demarcation between these divisions, as they 
 melt gradually one into the other like the colors of the visible spectrum. 
 When the heated matter is solid, such as the filament of an incandescent 
 lamp, the visible spectrum is usually continuous, that is, without lines or 
 bands; but when it is in the form of a gas or vapor, as in the iron arc 
 used for welding operations, the spectrum is divided up into bands or ia 
 crossed by lines which are characteristic of the element heated. 
 
24 ELECTRIC WELDING 
 
 The radiations under the foregoing three headings, although of common 
 origin, produce very diverse effects upon our senses. Thus, the infra-red 
 rays produce the sensation of heat when they fall on our unprotected skin, 
 but they are invisible to our eyes. The visible light rays enable us to 
 see; but we have no sense that perceives the ultra-violet rays, so that we 
 know of them only by their effects. 
 
 The intense glare emitted in the process of arc welding consists of 
 a combination of all these rays, and special safety devices are required to 
 protect the operator from their harmful effects. 
 
 For welding with acetylene and for light electric welding, it may be 
 necessary only to protect the eyes with goggles fitted with suitable colored 
 glasses. 
 
 A hand shield made of light wood, and which has a safety colored 
 glass window in the center is also sometimes used. This device is used 
 for medium weight electric welding done with one hand. The shield serves 
 the double purpose of protecting the eyes of the operator and also shielding 
 his face from the heat rays and the ultra-violet radiation, which might 
 otherwise cause a severe sunburn effect. 
 
 For heavy electric welding, which requires the use of both hands, 
 it is common practice for the operator to protect his eyes and neck with 
 a helmet fitted with a round or rectangular window of safety glass. These 
 helmets are usually made of some strong light material such as vulcanized 
 fiber and are designed so that they can be slipped on and off easily, 
 the weight resting on the shoulders of the operator. 
 
 There are a great many different kinds of special safety glasses on 
 the market, and many combinations of ordinary colored glass are also 
 in common use, so a brief discussion of this very important subject is 
 in order. 
 
 It is well known that the normal human eye shows considerable chromatic 
 aberration towards the red and blue-violet ends of the spectrum and that 
 this defect is completely corrected in regard to the middle colors. It, 
 therefore, naturally follows that a much clearer definition of an object 
 is obtained by combinations of yellow-green light than by red alone, or 
 especially by blue or violet light alone. The eye is also more sensitive 
 to the yellow and green rays than it is to the red and blue rays; or in 
 other words, yellow-green light has the highest luminous efficiency. This 
 may easily be verified by looking at a sunlit landscape or fleecy clouds 
 in a blue sky through plates of different colored glass. A glass of a light 
 amber color or amber slightly tinted with green will clearly bring out 
 details that are hardly observable without the glass, and which will be 
 obscured entirely by a blue or violet glass. It is therefore obvious that in 
 order to obtain the clearest definition or visibility with the least amount 
 of glare, the selection of the color tint in safety glasses should properly 
 be decided by an expert; but the depth of tint or, in other words, the 
 amount of obscuration may be determined best by the operator himself, 
 owing to the individual difference in visual acuity which will permit one 
 man to see clearly through a glass that would be too dark for another man. 
 
 When the invisible infra-red rays encounter any material which they 
 
ARC WELDING EQUIPMENT 25 
 
 cannot penetrate, or which is opaque to them, they are absorbed and are 
 changed into heat. Hence, they are frequently termed heat rays. It is, 
 therefore, very necessary to guard the eyes from these rays; and although 
 they are absorbed to a certain extent by ordinary colored glass, this is 
 not sufficient protection against any intense source. There are, however, 
 several kinds of glass, which, although fairly transparent to visible light, 
 are wonderfully efficient in absorbing heat. The effects of even low-power 
 heat rays, when generated in close proximity to the eyes for considerable 
 time, are often serious, as is evidenced by the fact that glass blowers, 
 who use their unprotected eyes near to hot gas flames of weak luminous 
 intensity, are frequently afflicted with cataract which might be positively 
 avoided by wearing properly fitted spectacles. 
 
 In selecting colored glasses, great care should be taken to discard all 
 samples that show streaks or spots, as these defects are liable to produce 
 eye-strain. The glass should be uniform in color and thickness throughout, 
 and the colored plate should be protected from outside injury by a thin 
 piece of clear glass that can easily be renewed. 
 
 Table II indicates roughly the percentage of heat rays transmitted 
 by various colored glasses of given thickness. The source of heat used 
 was a 200-watt, gas-filled Mazda lamp operating at a temperature of about 
 2400 deg. C. Although the figures are substantially correct for the samples 
 tested, they would necessarily vary somewhat for other samples of different 
 thickness and degrees of coloration, so that they can be taken only as a 
 general guide for comparative purposes. Examination of the table will 
 show that the last three, or commercial samples, all show better than 90 
 per cent exclusion of the heat rays. 
 
 TABLE II. QUALITIES OF VARIOUS KINDS OF GLASS 
 
 Per Cent 
 
 Thickness Heat Rays 
 
 in Inches Trans- 
 
 Kind of Glass mitted 
 
 Clear white mica 0.004 81 
 
 Clear window glass 0.102 74 
 
 Flashed ruby 0.097 69 
 
 Belgium pot yellow 0.126 50 
 
 Cobalt blue 0.093 43 
 
 Emerald green 0.100 36 
 
 Dark mica 0.007 15 
 
 Special light green glass 0.09.5 10 
 
 Special dark glass 0.096 4 
 
 Special gold-plated glass 0.114 0.8 
 
 As to the invisible ultra-violet rays, they are principally to be feared 
 not only because they are invisible, but because we have no organ or 
 sense for detecting them, and we can only trace their existence by their 
 effects. In all cases, however, when we are forewarned of their presence, 
 they are very easily shielded, for there are only a few substances which 
 
26 ELECTRIC WELDING 
 
 are transparent both to visible light and to ultra-violet radiation. Foremost 
 among these latter substances, because it is most common, is clear natural 
 quartz or rock crystal, from which the so-called "pebble" spectacle lenses 
 are made. Fluorite and selenite are also transparent to ultra-violet rays, 
 but these crystalline materials are rare and not in common use. However, 
 a moderate thickness of ordinary clear glass, sheets of clear or amber 
 mica, and of clear or colored celluloid or gelatine are opaque to these 
 dangerous rays. As a case in point, it is well known that the mercury 
 vapor lamp, when made with a quartz tube, is an exceedingly dangerous 
 light to the eye, being a prolific source of ultra-violet radiation, so that 
 when it is used for illumination, it is always carefully enclosed in an 
 outer globe of glass. When the mercury vapor lamp, however, is made 
 with a clear glass tube it is a harmless, if not very agreeable, source of 
 light, because the outer tube of clear glass is opaque to the ultra-violet 
 rays that are generated abundantly within it by the highly luminescent 
 mercury vapor. 
 
 When operating with a source of light that is known to be rich in 
 ultra-violet rays, such as the iron arc in welding operations, it is not 
 sufficient to guard the eyes with ordinary spectacles because these invisible 
 rays are capable of reflection, just the same as visible light, and injury 
 may easily ensue from slanting reflections reaching the eye behind the 
 spectacle lenses. Goggles that fit closely around the eyes are the only 
 sure protection in such cases. Also, when using a hand shield it should 
 be held close against the face and not several inches away from it. 
 
 It may here be mentioned that the invisible ultra-violet rays, when they 
 are not masked or overpowered by intense visible light, produce the curious 
 visible effect termed "fluorescence" in many natural and artificial com- 
 pounds. That is, these rays cause certain compounds to shine with various 
 bright characteristic colors, when by visible light alone they may appear 
 pure white or of some weak neutral tint. Thus, natural willemite, or zinc 
 silicate, from certain localities (which may also le made artificially) 
 shows a bright green color under the light from a disruptive spark between 
 iron terminals; whereas this compound is white or nearly so by visible 
 light. Also, all compounds of salicylic acid, such as the sodium salicylate 
 tablets which may be bought at any drug store, are pure white when seen 
 by visible light, but show a beautiful blue fluorescence under ultra-violet 
 rays. Many other chemical compounds could be mentioned which possess 
 this curious property, but the above substances will suffice to illustrate 
 the effect of fluorescence produced by ultra-violet rays, and by which these 
 rays may be thereby detected. It must, however, be noted that these 
 substances will only show their fluorescent colors very faintly when viewed 
 by the light of the low-tension iron arc used in welding, because the intense 
 visible light of this arc will overpower the weaker effect of the invisible 
 ultra-violet rays. The true beauty of fluorescent colors can only be seen 
 under a high-tension disruptive discharge between iron terminals, the visible 
 light in this case being weak while the ultra-violet rays are comparatively 
 intense. 
 
 Summarizing the effective means for eye protection against the various 
 
ARC WELDING EQUIPMENT 27 
 
 harmful radiations that are particularly associated with welding operations: 
 
 (1) The intense glare and flickering of the visible rays should be 
 softened and toned down by suitably colored glasses, selected by an expert 
 and having a depth of coloration which shows the clearest definition com- 
 bined with sufficient obscuration of glare, which last feature can be best 
 determined by the individual operator. 
 
 (2) When infra-red rays are present to a dangerous degree, a tested 
 heat-absorbing or heat-reflecting glass should be employed, either in com- 
 bination with a suitable dark colored glass, when glaring visible light is 
 present, or by itself in cases where the visible rays are not injuriously 
 intense. 
 
 (3) In guarding the eye from the dangerous ultra-violet rays, it must 
 be carefully noted that "pebble" lenses are made from clear quartz 
 or natural rock crystal, and this material being transparent to these rays 
 offers no protection against their harmful features. On the other hand, 
 ordinary clear glass is a protection against these rays when they are not 
 very intense, but dark-amber or dark-amber-grecn glasses are absolutely 
 protective. Glasses showing blue or violet tints should be avoided, excepting 
 in certain combinations wherein they may be used to obscure othor colors. 
 
 UNIVERSITY OF CALIFORNIA 
 EPARTMENT OF C,V,L ENGINEER,,* 
 BERKELEY, CALIFORNIA 
 
CHAPTER III 
 DIFFERENT MAKES OF ARC WELDING SETS 
 
 In showing examples of different makes and types of arc 
 welding sets, only enough will be selected to cover the field in 
 a general way, and no attempt whatever will be made to make 
 the list complete. 
 
 The General Electric Co., Schenectady, N. Y., puts out the 
 
 FIG. 22. Oeneral Electric 3-KW., 1700-K.P.M., 125-60-20- V. Compound- 
 wound Balancer-Type Arc Welding Set. 
 
 constant energy metallic electrode set shown in Fig. 22. This, 
 however, is but one type of its machines as this company makes 
 a varied line covering all needs for welding work. Two of their 
 commonly used, up-to-date sets are illustrated in Figs. 131 and 
 132, Chapter VIII. 
 
 This particular machine combines high arc efficiency and 
 light weight. The balancer set is of the well-known G-E standard 
 "MCC" construction. It is built for operation on 125-v., d.c. 
 supply circuits, which may be grounded on the positive side only, 
 and is rated "MCC" 3 kw., 1,700 revolution, 125/60/20 v., com- 
 
 28 
 
DIFFERENT MAKES OF ARC WELDING SETS 29 
 
 pound-wound, 150 amperes, RC-27-A frames, the two armatures 
 being mounted on one shaft and connected in series across the 
 125-v. supply circuit, one welding circuit terminal being taken 
 from the connection between the two armatures and the other 
 from the positive line. By this means each machine supplies 
 part of the welding current and, consequently, its size and weight 
 is minimized. The design of the fields and their connections 
 is such that the set delivers the voltage required directly to the 
 arc without the use of resistors or other energy-consuming 
 devices. The bearings are waste packed: this type of bearing 
 
 FIG. 23. Welding Control Panel for Balancer Set. 
 
 being desirable in a set which is to be made portable either for 
 handling by a crane or for mounting on a truck. 
 
 The welding control panel for the balancer set is shown in 
 Fig. 23. This panel consists of a slate base, 24-in. square, which 
 is mounted on 24-in. pipe supports for portable work and on 
 64-in, pipe supports for stationary work. 
 
 The entire set consists of one ammeter, one voltmeter, one 
 dial switch, two field rheostats (motor and generator) one start- 
 ing equipment witlf fuse, one reactor mounted on the pipe frame 
 work of panel. The ammeter and voltmeter are enclosed in a 
 common case. The ammeter indicates current in the welding 
 
30 
 
 ELECTRIC WELDING 
 
 circuit and the voltmeter is so connected that by means of a 
 double-throw switch, either the supply line voltage or the welding 
 line voltage can be read. 
 
 The dial switch is connected to taps in the series field of 
 
 -t-itr 
 
 La 
 
 185 V. D. C. 
 Reactor 
 
 Voltmeter Ammeter 
 
 AS 
 
 L 
 
 ' 
 
 \ l!r% 
 
 > N 
 ZzfFuse 
 
 CRIOOO Starter 
 
 JftA J 
 
 To 
 
 LI 
 
 Al 
 
 Electrode 
 
 To Work 
 
 probably 
 
 grounded 
 
 Series 
 Field 
 Shunt Field 
 
 Series 
 Field 
 
 Com 'IT?. 
 
 Field Armature 
 
 Co mm. Generator 
 Field Armature 
 
 FIG. 24. Balancer and Control Panel Connections for General Electric 
 Constant-Energy Constant-Arc Set. 
 
 the generator, the field being connected to oppose the main field. 
 This feature provides the current control by which six steps 
 are obtained of the approximate values of 50, 70, 90, 110, 130 and 
 150 amp., which enables the operator to cover a very wide range. 
 
DIFFERENT MAKES OF ARC WELDING SETS 
 
 31 
 
 In addition, if intermediate current values are required, they can 
 be obtained by means of the generator field rheostat. 
 
 A small reactor is used to steady the arc and current both 
 on starting and during the period of welding. 
 
 Arc welding is usually done on metal which is grounded and 
 this is especially unavoidable in ship work, where the ship struc- 
 ture is always well grounded. Since successful operation requires 
 that the positive terminal be connected to the work the supply 
 circuit should be safely grounded on the positive side. 
 
 Where a 125-v., d.c. supply system is not available, standard 
 
 Thickness 
 
 FIG. 25. Carbon Electrode Cutting Speeds for Different Thicknesses 
 
 of Plate. 
 
 "MIC" or "MCC" sets are furnished to supply power at 125 v., 
 the motor being either 3-phase, 60-cycle, 220, 440 or 550 v., or 
 d.c,, 230 or 550 v., and in three capacities, 5J kw., 7 kw., and 
 15 kw. With each motor generator set there is supplied a panel 
 containing generator field rheostat and motor starter, which may 
 be mounted beside the balancer panel. A diagram showing the 
 balancer and control panel is shown in Fig. 24. 
 
 The constant energy arc-welding equipment supplies, to the 
 arc, practically constant energy throughout the welding range 
 for metallic electrode welding only. If the arc is lengthened 
 slightly the voltage increases and the current decreases, the total 
 
32 
 
 ELECTRIC WELDING 
 
 
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DIFFERENT MAKES OF ARC WELDING SETS 
 
 33 
 
 energy being practically constant. As the voltage required by 
 the arc varies, the generator readjusts itself to this condition 
 and automatically supplies the required voltage; the remainder 
 being utilized by the motor end of the set. The interchange 
 of voltage between the motor and generator is practically in- 
 stantaneous, no perceptible lag occurs. This feature is valuable 
 when metal drops from the electrode and causes an instantaneous 
 increase in current. The commutation is sparkless and the weld- 
 
 Pie. 26. Wilson Two-Arc, 300 Amp., "Plastic Arc" Welding Set. 
 
 ing circuit may be short-circuited without injury to the machine. 
 
 In connection with welding with an outfit of this kind, the 
 practical man and student will find Table III of considerable 
 interest. For sheet steel cutting using the carbon arc, the 
 chart Fig. 25 is given. 
 
 The Wilson Outfit. The Wilson "plastic arc" process and 
 apparatus was first developed in railroad work by the Wilson 
 Welder and Metals Co., New York, in order to enable the 
 welder to control the heat used. By this system it is claimed 
 
34 
 
 ELECTRIC WELDING 
 
 that any number of operators can work from one large machine 
 without one welder interfering in any way with the work of 
 another. Each operator can have properly controlled heat and 
 a steady arc at the point of application. This system was 
 
 Fie. 27. Welding and Cutting Panel for Wilson Set. 
 
 largely used in the repair of the damaged engines on the Ger- 
 man ships which were seized by us. By regulating the heat 
 it is claimed that any metal can be welded without preheating. 
 A two-arc set is shown in Fig. 26 and a close-up of a control 
 panel in Fig. 27. 
 
DIFFERENT MAKES OF ARC WELDING SETS 35 
 
 This outfit consists essentially of a constant voltage 
 generator driven by any constant-speed motor, all mounted 
 on a common bedplate. The regulation of the welding current 
 is maintained by means of a series carbon pile acting as a 
 series resistance of varying quantity under the action of increas- 
 ing or decreasing mechanical pressure. This pressure is 
 produced by means of a series solenoid operating mechanically 
 on a lever and spring system which varies the pressure on 
 the carbon pile inversely as the current in the main circuit. 
 This establishes a constant current balance at any predeter- 
 mined adjustment between a maximum and minimum range 
 designed for. The change in adjustment is controlled by the 
 operator at the point of work by means of a small pilot motor 
 which shifts the lever center of the pressure mechanism, 
 thereby raising or lowering the operating current. This system 
 maintains a constant predetermined current at the arc regard- 
 less of the arc length. The operation of the mechanism is 
 positive and quick acting. A special series choke-coil is 
 mounted on the control panel for use as a cutting resistance. 
 
 " Plastic Arc" Dynamotor Unit. The "plastic arc" weld- 
 ing unit illustrated in Fig. 28, while embodying the same 
 fundamental principles as the foregoing, is a later model. This 
 set is composed of a dynamotor and current control panel. 
 The generator is flat-compound wound, and maintains the 
 normal voltage of 35 on either no load or full load. 
 
 The control panel has been designed to provide a constant- 
 current controlling panel, small in size, of light weight, 'simple 
 in operation and high in efficiency. The panel is of slate, 
 20 in.X27 in., and on it are mounted a small carbon pile, a 
 compression spring, and a solenoid working in opposition to 
 the spring. The solenoid is in series with the arc so that any 
 variation in current will cause the solenoid to vary the pressure 
 on the carbon pile, thereby keeping the current constant at the 
 value it is adjusted for. 
 
 Three switches on the panel provide an easy means of cur- 
 rent adjustment between 25 and 175 amperes. The arrange- 
 ment of the welding circuit is such that 25 amperes always 
 flow through the solenoid when the main switch is closed, 
 whether the welding current is at the minimum of 25 amperes 
 or the maximum of 175 amperes. The balance of the welding 
 
36 
 
 ELECTRIC WELDING 
 
 current is taken care of in by-pass resistances shunted around 
 the solenoid. 
 
 This outfit can be furnished as a dynamotor unit, with 
 standard motor characteristics as follows : 110 volts or 220 volts 
 direct current, or 220 or 440 volts, 60 cycle, 2 or 3 phase, 
 alternating current; also as a gasoline-driven unit, or it can 
 
 FIG. 28. " Plastic- Arc " Dynamotor Welding Unit. 
 
 be furnished without a motor, to be belt driven. The normal 
 generator speed is 1800 r.p.m. The net weight is 800 Ib. with 
 direct-current motor, 807 Ib. with alternating-current motor, 
 1200 Ib. with gasoline engine, and 550 Ib. as a belted outfit 
 without motor. The sets can be mounted on a truck for easy 
 portability if desired. 
 
 The Lincoln Outfit. The portable arc-welding outfit illus- 
 
DIFFERENT MAKES OF ARC WELDING SETS 
 
 37 
 
 trated in Fig. 29 is the product of the Lincoln Electric Co., 
 Cleveland, Ohio. The outfit is intended for operation where 
 electric current is not available and consists of a 150-amp. 
 arc-welding generator direct connected to a Winton gasoline 
 engine. An interesting feature of the machine is the method 
 used to insure a steady arc and a constant and controllable 
 heat. A compound-wound generator is used, the series wind- 
 
 FIG. 29. Lincoln Self-Contained Portable Set. 
 
 ings of which are connected to oppose the shunt field, the two 
 windings being so proportioned that the voltage increases in 
 the same ratio that the current increases, thus limiting the 
 short-circuit current. Another important effect of this is that 
 the horsepower, and therefore the heat developed for a given 
 getting of the regulator switch shown on the control board 
 above the generator remains practically constant. It is claimed 
 that this method of control gives considerably more work 
 
38 
 
 ELECTRIC WELDING 
 
 on a given amount of electricity than where the machines use 
 the ballast resistance. Additional arc stability is insured by 
 the stabilizer at the right of the illustration, this being a highly 
 inductive low-resistance coil connected in the welding circuit 
 and serving to correct momentary fluctuations of current. 
 
 Westinghouse Single- Operator Electric Welding Outfit. 
 The single-operator electric arc-welding equipment shown in 
 Fig. 30 is manufactured by the Westinghouse Electric and 
 Manufacturing Co., East Pittsburgh, Pa. The generator 
 
 FIG. 30. Westinghouse Single-Operator Portable Outfit. 
 
 operates at arc voltage and no resistance is used in circuit 
 with the arc. The generator is designed to inherently stabilize 
 the arc, thereby avoiding the use of relays, solenoid control- 
 resistors, etc. 
 
 The generator has a rated capacity of 175 amp. and is 
 provided with commutating poles and a long commutator, 
 which enable it to carry the momentary overload at the instant 
 of striking an arc without special overload device. Close adjust- 
 ment of current may be easily and quickly made, and, once 
 
DIFFERENT MAKES OF ARC WELDING SETS 
 
 39 
 
 made, the amount of current at the weld will remain fixed 
 within close limits until changed by the operator. There are 
 twenty-one steps provided which give a current regulation of 
 less than 9 amp. per step and make it much easier for a welder 
 to do vertical or overhead work. 
 
 The generator is mounted on a common shaft and bedplate 
 with the motor. A pedestal bearing is supplied on the com- 
 mutator end and carries a bracket for supporting the exciter 
 which is coupled to the common shaft. Either d.c. or a.c. 
 motors can be supplied. Where an a.c. motor is used leads 
 
 
 FIG. 31. U. S. L. Portable, A-C. Motor-Generator Set. 
 
 are brought outside the motor frame for connecting either 
 220- or 440-v. circuits. An electrician can change these con- 
 nections in a few minutes' time. This feature is desirable on 
 portable outfits which may be moved from one shop to another 
 having a supply circuit of different voltages. For portable 
 service, the motor-generator set with the control panel is 
 mounted on a fabricated steel truck, equipped with roller- 
 bearing wheels. The generator is compound-wound, flat com- 
 pounded, that is, it delivers 60 v. at no-load and also at full- 
 load. 
 
40 ELECTRIC WELDING 
 
 The U. S. Light and Heat Co.'s Outfit. The portable outfit, 
 Fig. 31, is made by the U. S. Light and Heat Corp., Niagara 
 Falls, N. Y. It is 28 in. wide, 55 in. high, 54 in. long, and 
 will pass through the narrow aisle of a crowded machine shop. 
 It weighs 1,530 Ib. complete. In case a d.c. converter is used, 
 the weight is about 125 Ib. less. Curtains are provided to keep 
 out dirt. A substantial cable reel is provided carrying two 
 50-ft. lengths of flexible cable for carrying the current to the 
 arc. The reel is controlled by a spring which prevents the 
 paying out of more cable than the welder needs. The outfit 
 is made in several models to use 4 kw., 110-220-440-550 v., 
 2 and 3 phase, 25 and 60 cycle. 
 
 The Arc Welding Machine Co.'s Constant-Current Closed- 
 Circuit System. The constant-current closed-circuit arc welding 
 
 fefcrf 
 
 FIG. 31A. The Are Welding Machine Co.'s Outfit. 
 
 system developed by the Arc Welding. Machine Co., New York, 
 permits the use of an inherently regulating generator with more 
 than one arc on a single circuit. This system is claimed to be 
 especially adapted to production welding applications. 
 
 The method has all the advantages of series distribution, 
 namely, the size of wire is uniform throughout the system and 
 carries a uniform current, independent of the length of the 
 circuit as well as of the number of operators. The circuit is 
 simply a single wire of sufficient cross-section to carry the 
 current for one arc, run from the generator to the nearest arc, 
 from there to the next, and so on back to the generator. 
 Wherever it is desired to do welding, a switch is inserted in 
 the line, and a special arc controller provided with suitable 
 connections is plugged in across the switch whenever work 
 
DIFFERENT MAKES OF ARC WELDING SETS 41 
 
 is to be done. These controllers may be made portable or 
 permanently mounted at the welding station. 
 
 The set shown in Fig. 31A consists of two units: The 
 generator proper which furnishes the energy for welding, and 
 the regulator which automatically maintains the current at a 
 constant value. The regulator is excited from a separate 
 source, and, by varying its excitation with an ordinary field 
 rheostat, the main welding current may be set at any value 
 within the range of the machine that is desired, and once set 
 it will automatically maintain that value. 
 
 Each arc that is operated on the system is equipped with 
 an automatic controller which serves two essential purposes: 
 
 1 It maintains at all times the continuity of the circuit, 
 so that one arc cannot interfere with any of the 
 others when it comes on, or goes out of, the circuit. 
 
 2 It controls automatically the heat which can be put 
 into the metal of the weld. 
 
 The current through the arc, together with the size of the 
 electrode, determines the flow of metal from the electrode, and 
 this current is adjusted by shunting a portion of the main 
 current around the arc. The regulation characteristic of the 
 arc may be adjusted by a series parallel resistance, which is 
 one of the special features. When doing work on very thin, 
 light metals, especially where the weld must be tight, it is 
 necessary that fusion take place from the first instant the 
 arc is struck. If the heat of the arc is exactly right for 
 continuous operation, it will not be enough at the first instant, 
 and if it is sufficient to produce fusion at once, then it will 
 be too much a few seconds later. On this account a special 
 type of controller is used for such work which provides for 
 automatic reduction at a definite time after the arc is actually 
 started, and continuing for a definite time and at a definite 
 rate. Both periods of time and the rate and magnitude of 
 the current change are adjustable. 
 
 For a given flow of metal through the arc the temperature 
 of the metal is determined by the length of the arc, that is, 
 by the voltage. With this controller, the length of the arc 
 limited by the voltage is adjusted to suit the work and the 
 operator, and if exceeded, the arc is short-circuited automat- 
 
42 
 
 ELECTRIC WELDING 
 
 ically and remains short-circuited until the welder is ready 
 to begin again. 
 
 Provision is also made for stopping the arc at will without 
 lengthening it. Therefore it is claimed that with this system 
 it is impossible to draw a long arc and burn the metal. The 
 arc is not broken when the welding operation is stopped, but 
 is killed by a short-circuit which is placed across it. 
 
 FIG. 32. Zeus Arc- Welding Outfit. 
 
 Stopping an arc by short-circuiting and limiting the heat 
 production in the same way is a patented feature. 
 
 "Zeus" Arc- Welding Outfit. The "Zeus" arc-welding out- 
 fit shown in Fig. 32 is a product of the Gibb Instrument Co., 
 1644 Woodward Ave., Detroit, Mich. In this device the motor- 
 generator customarily used has been supplanted by a trans- 
 
DIFFERENT MAKES OF ARC WELDING SETS 43 
 
 former with no moving parts. The outfit is built on a unit 
 system, which allows the installation of a small outfit, and 
 if the work becomes heavier a duplicate set may be connected 
 in parallel. One of the features of the machine is the arrange- 
 ment for regulation. It is not necessary to change any con- 
 nection for this purpose, as a wheel connected with a secondary 
 and placed on the top of the case raises and lowers this 
 secondary, and provides the regulation of current necessary for 
 
 FIG. 33. Arcwell Outfit for Alternating Current. 
 
 different sizes of electrodes. The inherent reactance of the 
 outfit automatically stabilizes the arc for different arc lengths. 
 The Arcwell Outfit. The Arcwell Corporation, New York, 
 has on the market an electric welding apparatus built for 
 operation on alternating current of any specified voltage or 
 frequency. It is shown in Fig. 33. It differs from the com- 
 pany's standard outfit in that it is being put out expressly 
 for the use of smaller machine shops and garages, its capacity 
 not being sufficient to take care of heavy work on a basis of 
 
44 ELECTRIC WELDING 
 
 speed. It will do any work that can be done by the larger 
 machines, but the work cannot be performed as rapidly, the 
 machine being intended especially for use by concerns who 
 have only occasional welding jobs to perform. The machine 
 weighs approximately 200 Ib. and, being mounted on casters, 
 it can be moved from one job to another. 
 
 Alternating-Current Arc- Welding Apparatus. The Electric 
 Arc Cutting and Welding Co., Newark, N. J., is now marketing 
 the alternating-current arc-welding outfit shown in Fig. 34. 
 
 This illustration shows the entire apparatus for use on a 
 
 FIG. 34. Apparatus Made by the Electric Arc Cutting and Welding Co. 
 
 single-phase circuit, the current being brought in through the 
 wires seen protruding at the lower left corner. 
 
 The device consists principally of a transformer with no 
 moving parts and is claimed to last indefinitely. In this ap- 
 paratus, instead of holding either current or voltage constant 
 as with direct-current sets, the wattage, or the product of 
 voltage and current, is held constant. The alternating-current 
 set holds the arc wattage without moving parts ; hence the heat 
 is substantially constant for any given setting, and it is claimed 
 that as soon as any person becomes accustomed to the sound 
 and sight of the arc and can deposit the molten metal where 
 he desires it is impossible to burn the metal from too much 
 heat or make cold-shut welds from too little heat. The amount 
 
DIFFERENT MAKES OF ARC WELDING SETS 45 
 
 of heat generated is controlled by means of an adjusting handle 
 on the transformer together with taps arranged on a plugging 
 board. It is stated that the kilowatt-hours required to deposit 
 a pound of mild steel with this machine varies from 1 to 2. 
 Their largest set is a 60-cycle type weighing about 200 lb., 
 which places it in the portable class. The set can be furnished 
 for any a.c. power supply, but it is not advisable to use a 
 greater voltage than 650 on the primary. The set can also be 
 made single phase, two phase three wire, two phase four wire, 
 
 
 FIG. 35. General Electric Lead-Burning Outfit. 
 
 to operate across the outside wires of the two-phase system 
 or from a three-phase power supply. Polyphase sets are about 
 30 per cent -heavier than the single-phase sets. In the two- 
 phase machine balanced current can be drawn from each of 
 the two phases by placing the sets across the outside wires. 
 This is advocated, as it provides for leading current on one 
 phase which brings up the total power factor of the system and a 
 better power rate can be obtained. In polyphase circuits where 
 more than one set is used single-phase sets can be distributed 
 among the several phases. 
 
 The outfit can be made especially for welding and for cut- 
 
46 ELECTRIC WELDING 
 
 ting or for combination welding and cutting and can make 
 use of bare wire, slag-covered, gaseous fluxed or carbon elec- 
 trodes. An operator's mask and the electrode holder used 
 may be seen on top of the apparatus. 
 
 General Electric Lead-Burning Transformer. This lead- 
 burning transformer, Fig. 35, a product of the General Electric 
 Co., Schenectady, N. Y., can be used for lead burning, soldering 
 electric terminals, splicing wires and tinsmith jobs, and even 
 brazing can be done by placing the work between a blunt 
 carbon point and a piece of cast iron. The transformer is 
 designed to be connected to the ordinary 110-v., a.c. lighting 
 circuit. Heavy rubber-covered terminal leads are used to 
 convey the low-voltage, heat-producing current to the work, 
 one terminal ending in a clip for fastening to some convenient 
 portion of the work while the other terminal has a carbon 
 holder arranged with an insulated handle. When the welding 
 carbon is brought into contact with the work the pointed end 
 becomes intensely hot and melts the metal over a restricted 
 area. It should be noted that no arc is drawn, the end of 
 the carbon point being heated to such a temperature that, the 
 metal in the vicinity is melted. The device uses about 800 
 watts while in actual use, the consumption dropping to 4J 
 watts when the point is removed from the work. It is stated 
 that the device is very convenient in plumbing, roofing and 
 tank-building jobs, as well as other such work. 
 
CHAPTER IV 
 TRAINING ARC WELDERS 
 
 Writing on the training of arc welders, in the American 
 Machinist, April 15, 1920, 0. H. Eschholz, research engineer 
 of the Westinghouse Electric and Mfg. Co., Pittsburgh, says : 
 
 Many industrial engineers are now facing the problem of 
 developing competent welders. This situation is attributed to 
 the rapid growth of the metallic electrode arc-welding field 
 as the result of the successful application of the process to 
 war emergencies. The operator's ability, it is now generally 
 conceded, is the most important factor in the production of 
 satisfactory welds. To facilitate the acquirement of the neces- 
 sary skill and knowledge, the following training course con- 
 siders in their proper sequence the fundamental characteristics 
 and operations of the bare metallic electrode arc-welding 
 process. 
 
 It is well known that the iron arc emits a large quantity 
 of ultra-violet radiation. Protection from the direct rays is 
 usually afforded by the use of hand shields. Many uncom- 
 fortable burns, however, have been traced to reflected radiation. 
 To secure adequate protection from both direct and reflected 
 light it is necessary for the welder to use a fiber hood equipped 
 with suitable glasses. Paper No. 325 of the Bureau of 
 Standards on " Spectroradiometric Investigation of the Trans- 
 mission of Various Substances" concludes that the use of amber 
 and blue glasses will absorb most of the ultra-violet as well 
 as infra-red radiation. To protect the operator from incan- 
 descent particles expelled by the arc, closely woven clothing, 
 a leather apron, gauntlets and bellows-tongued shoes should 
 be worn. 
 
 If the welding booth is occupied by more than one welder, 
 it will be found desirable to equip each operator with amber 
 or green-colored goggles to reduce the intensity of accidental 
 
 47 
 
48 ELECTRIC WELDING 
 
 " flashes" from adjacent arcs after the welder has removed 
 his hood. 
 
 The Welding Booth. The difficulty of maintaining an arc 
 is greatly increased by the presence of strong air currents. To 
 avoid the resulting arc instability, it is desirable to inclose 
 the welder on at least three sides, with, however, sufficient 
 ventilation provided so that the booth will remain clear from 
 fumes. By painting the walls a dull or matte black the amount 
 of arc radiant energy reflected is reduced. 
 
 The electrode supply and means of current control should 
 be accessible to the operator. When using bare electrodes the 
 positive lead should be firmly connected to a heavy steel or 
 cast-iron plate, mounted about 20 in. above the floor. This 
 plate serves as the welding table. 
 
 Welding Systems. Many commercial sets compel the 
 operator to hold a short arc. This characteristic favors the 
 production of good welds but increases the difficulty of main- 
 taining the arc. By increasing the stability of the arc through 
 the use either of covered electrodes, series inductances or in- 
 creased circuit voltage and series resistance, the acquisition of 
 the purely manipulative skill may be accelerated. 
 
 The Electrode Holder. The electrode holder should remain 
 cool in service, shield the welding hand from the arc, facilitate 
 the attachment and release of electrodes, while its weight, 
 balance and the drag of the attached cable should not produce 
 undue fatigue. A supply of different types of covered and 
 bare electrodes should be carried by the welding school so 
 that the operator may become familiar with their operating 
 and fusing characteristics. 
 
 The degree of supervision the welder is to receive de- 
 termines the source of operator material. If the welding opera- 
 tions are to be supervised thoroughly and the function of the 
 welder is simply that of uniting suitably prepared surfaces, 
 the candidate may be selected from the type of men who usually 
 become proficient in skilled occupations. If, however, the 
 responsibility of the entire welding procedure rests upon the 
 operator, he should be drawn from members of such metal 
 trades as machinist, boilermaker, blacksmith, oxy-acetylene 
 welder, etc. Some employers find it expedient to use simple 
 eve and muscular co-ordination tests to determine the candi- 
 
TRAINING ARC WELDERS 
 
 49 
 
 date's ability to detect the colors encountered in welding and 
 to develop an automatic control of the arc. 
 
 With adequate equipment provided, the operator may be 
 instructed in the following subjects: 
 
 1. Manipulation of the arc. 
 
 2. Characteristics of the arc. 
 
 3. Characteristics of fusion. 
 
 4. Thermal characteristics. 
 
 5. Welding procedure. 
 
 6. Inspection. 
 
 Arc Manipulation. A sitting posture which aids in the 
 control of the arc is shown in Fig. 36. It should be noted that 
 
 FIG. 36. Correct Welding Posture and Equipment. 
 
 by resting the left elbow on the left knee the communication 
 of body movements to the welding hand is minimized, while by 
 supporting the electrode holder with both hands the arc may 
 be readily directed. During the first attempts to secure arc 
 control covered electrodes may be used, as these greatly increase 
 arc stability, permitting the welder to observe arc characteris- 
 
50 ELECTRIC 1YELDING 
 
 tics readily. It is suggested that throughout the training period 
 the instructor give frequent demonstrations of the welding 
 operations as well as occasionally guide the apprentice's weld- 
 ing arm. 
 
 Arc Formation. With the welding current adjusted to 100 
 amp. and a 5 / S2 -ui. covered electrode in the holder, the operator 
 assumes the posture shown and lowers the electrode until con- 
 tact is made with a mild-steel plate on the welding table, 
 whereupon the electrode is withdrawn, forming an arc. If an 
 insulating film covers either electrode surface or the current 
 adjustment is too low, no arc will be drawn. With the arc 
 obtained the operator should note the following characteristics 
 of arc manipulation. 
 
 Fusion of Electrodes. The fusion of electrodes is frequently 
 called "sticking" or " freezing. " It is the first difficulty 
 encountered and is caused either by the use of an excessive 
 welding current or by holding the electrodes in contact too 
 long before drawing the arc. This fusing tendency is always 
 present because the welding operation requires a current den- 
 sity high enough to melt the wire electrode at the arc terminal. 
 When such fusion occurs the operator commits the natural 
 error of attempting to pull the movable electrode from the 
 plate. If he succeeds in separating the electrodes, the momen- 
 tum acquired, unless he is very skillful, is sufficient to carry 
 the electrode beyond a stable arc length. If, however, the wrist 
 of the welding hand is turned sharply to the right or left, 
 describing the arc of a circle having its center at the electrode 
 end, the fused section is sheared and a large movement of the 
 electrode holder produces an easily controllable separation of 
 the arc terminals. 
 
 Maintenance of Arc. After forming the arc the chief con- 
 cern of the welder should be to maintain it until most of the 
 electrode metal has been deposited. If the movable electrode 
 were held rigidly, the arc would gradually lengthen as the 
 electrode end melted off until the arc length had increased 
 sufficiently to become unstable and interrupt the flow of cur- 
 rent. To maintain a constant stable arc length it is necessary 
 for the operator to advance the wire electrode toward the plate 
 at a rate equal to that at which the metal is being deposited. 
 For the novice this will prove quite difficult. However, if the 
 
TRAINING ARC WELDERS 51 
 
 initial attempts are made with covered electrodes, which per-" 
 mit greater arc-length variations than bare electrodes, the 
 proper degree of skill is soon acquired. 
 
 When the operator succeeds in maintaining a short arc 
 length for some time, the covered electrode should be replaced 
 by a 5 / 32 -i n - diameter bare electrode, the welding current in- 
 creased to 150 amp. or 175 amp. and either reactance included 
 in the circuit or the voltage of the welding set increased. With 
 increase in manipulative skill the reactance coil may be short- 
 circuited or the supply voltage reduced to normal and practice 
 continued under commercial circuit and electrode conditions. 
 
 Further instruction should not be given until the candidate 
 is able to maintain a short arc during the entire period required 
 to deposit the metal from a bare electrode 14 in. long, 5 / 32 in. 
 in diameter, on a clean plate j in. in thickness when using 
 a welding current of 150 amp. The arc voltage may be used 
 as a measure of the arc length. The average arc voltage 
 during the test should be less than twenty-five, as this 
 corresponds to a length of approximately J in. Some operators 
 meet this test in the first hour of their training, others require 
 two or three days' practice. If arc-length control is not 
 obtained within the latter period, the instructor may safely 
 conclude that the apprentice is physically unfitted for the occu- 
 pation of arc welding. If the test is satisfactory, training 
 should be continued, using bare electrodes but with such 
 stabilizing means as inductance or resistance again inserted in 
 the circuit. 
 
 Control of Arc Travel; Direction and Speed. The plate arc 
 terminal and the deposited metal follow the direction taken 
 by the pencil electrode. The difficulty of forming deposits 
 varies with the direction. The first exercise should consist in 
 forming a series of deposits in different directions, as shown 
 in A, Fig. 37, until the operator develops the ability to form 
 a series of straight, smooth-surfaced layers. Additional skill 
 may be acquired by the practice of forming squares, circles 
 and initials. 
 
 The speed of arc travel determines the height of the deposit 
 above the parent metal. A second exercise should require the 
 formation of deposit strips having heights of y ie , a / 8 and 
 Vie i n - The normal height of a deposit when using a welding 
 
52 
 
 ELECTRIC WELDING 
 
 'current of 150 amp. and a bare electrode of 5 / 32 in. diameter 
 is approximately -J in. 
 
 Weaving. If the electrode end is made to describe the arc 
 of a circle across the direction of deposit formation, the width 
 of the deposit may be increased without changing the height 
 of the deposit. This weaving movement also facilitates slag 
 notation and insures a more complete fusion of the deposited 
 metal to the parent metal. B and C, Fig. 37, illustrate the 
 appearance of deposits formed with and without weaving of 
 the electrode. 
 
 A third exercise should consist in forming layers of equal 
 
 A B C 
 
 FIG. 37. Control of Arc Direction Exercise. 
 
 (A) Exercise to develop control of arc direction. (B) Effect of weaving elec- 
 trode across direction of deposit. (C) Effect of not weaving. These deposits were 
 formed with the operator and plate in the same relative position, necessitating a 
 change in the direction of arc travel for the deposition of each layer. Note that 
 this direction is indicated by the position of the crater terminating each strip as 
 well as by the inclination of the scalloped surface. 
 
 heights, but having widths of J, f, J and f in. when using an 
 arc current of 150 amp. and a 5 / 32 -in. diameter bare electrode. 
 
 As the welder should now be able to control direction, 
 height and width of deposits while maintaining a short arc, 
 he should be given the fourth exercise of forming tiers of 
 parallel, overlapping layers until inspection of the surface and 
 cross-sections of the built-up material indicates good fusion 
 of the metal as well as absence of slag and blowholes. 
 
 Arc and Fusion Characteristics. The arc is the welder's 
 tool. Its function is to transform electrical energy into highly 
 
TRAINING ARC WELDERS 53 
 
 concentrated thermal energy. This concentrated energy serves 
 to melt both the parent and the deposited metals at the elec- 
 trode terminals, the arc conveying the liquefied pencil into the 
 crater formed on the material to be welded. 
 
 The plate arc terminal will always appear as a crater if 
 a welding current is used. This crater is formed partly by the 
 rapid volatilization of the liquefied material and partly by the 
 expulsion of fluid metal due to the explosive expansion of 
 occluded gases suddenly released or of gases formed by 
 chemical reaction between electrode materials and atmospheric 
 gases. To secure good fusion the deposited metal should be 
 dropped into the crater. This is facilitated by the use of a 
 short arc. . On welding, the operator should frequently note 
 the depth of arc crater and manipulate the arc so that the 
 advancing edge of the crater is formed on the parent metal 
 and not on the hot deposited metal. 
 
 Polarity. When using bare electrodes the concentration of 
 thermal energy is greater at the positive than at the negative 
 terminal. Since in most welding applications the joint has a 
 greater thermal capacity than the pencil electrode, more com- 
 plete fusion is assured by making the former the positive elec- 
 trode. The difference in concentration of thermal energy may 
 be readily illustrated to the welder by having him draw an 
 arc from a Vie-in, thick plate with the plate first connected 
 to a negative and then to the positive terminal. If a current 
 of approximately 60 amp. is used with a V 16 -in. diameter elec- 
 trode, he will be able to form a deposit on the plate, if the 
 plate is the negative terminal. On reversing the polarity, how- 
 ever, the energy concentration will be sufficient to melt through 
 the plate, thus producing a "cutting arc." 
 
 An arc stream consists of a central core of electrically 
 charged particles and an envelope of hot gases. The electrode 
 material is conveyed in both liquid and vapor form across the 
 arc, a spray of small globules being discernible with some types 
 of electrodes. Since atmospheric gases tend to diffuse through 
 this incandescent metal stream, it is obvious that some of the 
 conveyed material becomes oxidized. 
 
 Through the maintenance of a short arc, not exceeding -J 
 in., the resulting oxidation is a minimum because enveloping 
 oxide of manganese vapor and carbon dioxide gas, formed by 
 
54 
 
 ELECTRIC WELDING 
 
 the combination of atmospheric oxygen with the manganese 
 and carbon liberated from the electrodes, serves as a barrier 
 to restrict the further diffusion of atmospheric gases into the 
 arc stream. Fig. 38 illustrates the degree of protection afforded 
 the conveyed metal when using short and long arcs. With the 
 latter convection currents deflect the protecting envelope from 
 the arc stream. The effect of arc length on rate of oxidation 
 may be clearly indicated to the welder by forming deposits with 
 a |-in. arc and a f -in. arc on a clean plate. 
 
 The surface of the first deposit will be clean and smooth, 
 as shown at a, Fig. 39. The surface of the second deposit will 
 be irregular and covered with a heavy coating of iron oxide, 
 as shown at &. All oxide formed during welding should be 
 
 FIG. 38. Long and Short Welding Arc. 
 Large arc stream causes excessive oxidation. 
 
 floated to the surface, since its presence in the weld will reduce 
 the strength, ductility and resistance to fatigue of the joint. 
 Stability. The ease of maintaining an arc is determined by 
 the stabilizing characteristics of the electrical circuit and the 
 arc gase3. As noted above, increased stability may be obtained 
 by the use of series inductance or higher circuit voltage with 
 increased series resistance, higher arc currents and covered 
 electrodes. A high-carbon-content electrode, such as a drill 
 rod, gives a less stable arc than low-carbon content rods, owing 
 apparently to the irregular formation of large volumes of arc- 
 disturbing carbon-dioxide gas. Bare electrodes after long ex- 
 posure to the atmosphere or immersion in weak acids will be 
 found to "splutter" violently, increasing thereby the difficulty 
 of arc manipulation. This "spluttering" is apparently caused 
 
TRAINING ARC WELDERS 
 
 55 
 
 by irregular evolution of hydrogen. If the electrode is coated 
 with lime, its stability improves. 
 
 The evident purpose of a welding process is to secure fusion 
 between the members welded. The factors that determine 
 fusion in arc welding are arc current, electrode current density, 
 thermal capacity of joint sections and melting temperatures 
 of electrode and plate materials. By observing the contour 
 of the surface of the deposited metal as well as the depth of 
 the arc crater the welder may determine at once whether such 
 conditions under his control as arc current, electrode current 
 
 FIG. 39 Deposit Obtained with Short Are and Long Arc. 
 
 Note that surfaces of deposit and plate in (a) are comparatively clean, while 
 those in (&) are heavily coated with iron oxide. 
 
 density and electrode material are properly adjusted to produce 
 fusion. 
 
 The fifth exercise should consist of forming a series of 
 deposits with arc currents of 100, 150 and 200 amp., using 
 electrodes with and without coatings having different carbon 
 and manganese content. Cross-sections of the deposits should 
 then be polished and etched with a 10 per cent nitric-acid 
 solution and the surface critically examined for such evident 
 fusion characteristics as penetration and overlap, comparing 
 these with the surface characteristics. 
 
56 
 
 ELECTRIC WELDING 
 
 FIG. 40. Overlap and Penetration Studies. 
 
 (A) Typical section through a normal layer formed by depositing metal from 
 a mild- steel electrode on a mild-steel plate. Note the contour of the deposit as well 
 as that of the fused zone and the slight overlap and correct depth of deposit pene- 
 tration. Parent-metal crystal structure is altered by thermal changes. 
 
 (B) Typical section through a deposit formed when holding a long arc. Ex- 
 cessive overlap and no penetration exist. Most weld failures may be attributed to 
 the operator maintaining occasionally or continuously too long an arc. 
 
 (C) Section through crater formed on completing deposit strip. The depth of the 
 crater is a measure of the depth of penetration. 
 
 (D) Excessive overlap secured with a pencil electrode (drill rod) having a 
 lower melting temperature than the parent metal (mild steel). 
 
 (E) Elimination of overlap obtained by using a pencil electrode (mild steel) 
 having a higher melting temperature than the parent metal (cast iron). 
 
 (F) Incomplete fusion obtained with a low arc current. 
 
 (G) "Cutting" secured through use of high arc current. 
 
 (E) Section indicates proper selection of welding current and electrode diameter 
 to secure fusion. 
 
 (/) Poor fusion caused by too rapid flow thermal energy from deposit through 
 plates. 
 
 (/) Adequate fusion obtained by increasing arc terminal energy to compensate for 
 increased rate of heat flow. 
 
TRAINING ARC WELDERS 57 
 
 Overlap and Penetration. Examination of the boundary 
 line between the deposited and plate metals in A and B, Fig. 
 40, reveals that the penetration decreases in both directions 
 from the center of the layer, no fusion being evident at the 
 edges of the deposit, the contour betraying the extent of this 
 overlap. As shown in C the penetration may be estimated from 
 the crater depression. 
 
 An exaggerated overlap obtained in welding a mild-steel 
 plate with a high-carbon-content steel rod, having a lower melt- 
 ing point than the plate, is shown in D. The re-entrant angle 
 of the deposit edge is plainly evident. E illustrates a condi- 
 tion of no overlap in depositing metal from a mild-steel elec- 
 trode upon a cast-iron plate having a lower melting point. 
 F and G show respectively the effect of using too-low and too- 
 high arc currents. 
 
 The effect of heat conductivity, heat-storage capacity, ex- 
 pansion and contraction of the parent metal and contraction 
 of the hot-deposit metal must be studied. 
 
 Heat Conductivity and Capacity. The effect of any of 
 these factors is to increase the flow of thermal energy from the 
 plate arc terminal and therefore to reduce the amount of metal 
 liquefied. To maintain a given rate of welding speed it there- 
 for becomes necessary to increase the arc current with increase 
 in thickness or area of joint. 
 
 A welding current of 150 amp. will produce satisfactory 
 penetration on welding the apex of scarfed plates ^ in. thick 
 shown in H. If the joint is backed by a heavy steel plate, 
 increasing thereby both its thermal capacity and conductivity, 
 a higher current, in the neighborhood of 175 amp. to 200 amp., 
 will be required for the same penetration. If a lap joint is 
 made as in / and the same current used as in H, the flow of 
 heat will be so rapid that poor fusion will result. By increas- 
 ing the current to 225 amp., J, the desired penetration, as 
 indicated by crater depth, will be obtained with the main- 
 tenance of a high welding speed. 
 
 Expansion and Contraction of Parent Metal. The welding 
 operation necessarily raises the temperature of the metal adja- 
 cent to the joint, producing strains in the structure if it does 
 not expand and contract freely. This condition is particularly 
 marked when welding a crack in a large sheet or plate. The 
 
58 ELECTRIC WELDING 
 
 plate in the region of the welded section expands, the strains 
 produced react on the cold metal at the end of the crack 
 to open it further, with the result that as the welding proceeds 
 the plate continues to open at a rate about equal to the welding 
 speed. One inexperienced welder followed such an opening for 
 7 ft. before adopting preventive measures. The simplest of 
 these is to drill a hole at the end of the crack and follow an 
 intermittent welding procedure which will maintain the plate 
 at a low temperature. Under exceptional conditions, such as 
 welding cracks in heavy cast-iron plates or cylinders, it is 
 advisable to preheat and anneal the regions stressed. A second 
 example is offered by the warping obtained on building up the 
 diameter of a flanged shaft. The face of the flange adjacent 
 to the shaft becomes hotter than that opposite, producing 
 internal stresses which warp the flange to a mushroom shape. 
 Preheating of the flange will prevent this. 
 
 Contraction of Deposited Metal. The contraction of de- 
 posited metal is the most frequent cause of residual stress in 
 welds and distortion of the members welded. The magnitude 
 of "locked-in" stresses depends upon the welding procedure 
 and the chemical constituents of parent and deposited metals. 
 If the deposit is thoroughly annealed, practically no stress will 
 remain. On adopting a welding sequence in which the joint 
 is formed by running tiers of abutting layers, each newly 
 applied layer will serve partly to anneal the metal in adjacent 
 layers. If mild-steel plate, with less than 0.20 per cent carbon, 
 is welded in this way, the locked-in stresses should be less than 
 5,000 Ib. per square inch. With increase in carbon content the 
 locked-in stresses will increase. If welded joints of high-carbon 
 steels are not permitted to cool slowly, they will often fall 
 apart when the joint is given a sharp blow. 
 
 To illustrate this characteristic, the following exercises are 
 suggested : 
 
 Exercise 1 Deposit a layer 1 ft. long on a strip of steel 
 about Vie, i n - thick, x / 2 in. wide, using 150 amp. direct current 
 and a 5 / 32 -in. bare electrode. The longitudinal contraction of 
 the deposit will bend the strip of metal as shown in Fig. 41. 
 
 Exercise 2 Oeposit a layer of metal around the periphery 
 of a wrought-iron tube. The contraction of the deposit will 
 cause the tube to decrease in diameter. 
 
TRAINING ARC WELDERS 
 
 59 
 
 Exercise 3 Place two plates, J in. thick, 2 in. wide, 6 in. 
 long, -J- in. apart, and deposit a layer of metal joining them 
 together. The transverse contraction on cooling will pull the 
 plates out of line. 
 
 FIG. 41. Warping of the Parent Metal Caused by the Transverse Con- 
 traction of the Deposited Layers. 
 
 
 ^W FR DISTANCE ON 
 COOLING OF DEPOSIT 
 
 -ORIGINAL 
 DISTANCE" 
 
 FIG. 42. Reduction of "Free Distance" Caused by Transverse Contraction. 
 
 Illustrates the necessity of rigidly clamping the joint members, or of assembling 
 them by an increasing distance from the end to be first welded, to equalize the 
 movement caused by the contraction of the deposited metal, if the desired "free 
 distance" is to be maintained throughout the welding operation. 
 
 Exercise 4 If two plates, ^ in. thick, 6 in. wide and 6 in. 
 long, spaced -J in., are welded by depositing a short layer 
 extending J in. from the one end, it will be found that when 
 
60 
 
 ELECTRIC WELDING 
 
 the deposit has cooled the resulting transverse contraction will 
 not only warp the plates as in Exercise 3, but will also draw 
 them together as shown in Fig. 42, thereby decreasing the free 
 distance between plates. 
 
 Welding Procedure. Satisfactory welds will be obtained 
 only when the sections to be welded are properly scarfed or 
 cut out and the surfaces on which the deposits are formed 
 cleaned before and during the welding operation. The scarfs 
 may be machined or cut with a cold chisel or the carbon arc. 
 The surfaces of the deposited layers may be cleaned with a 
 
 FIG. 43. Welds Showing Poor and Good Fusion. 
 
 Section through one-half of a welded joint showing poor fusion obtained at apex 
 of V as the result of assembling the joint sections without a "free distance." Section 
 through one-half of a welded joint showing excellent fusion obtained as a result 
 of the use of a "free distance" of | in., thus permitting the operator to maintain a 
 short arc when welding the bottom of the V. Failures of deep welds may be usually 
 attributed to the use of too small a "free distance," low welding current, improper 
 cleaning of scarf faces or incomplete slag flotation. 
 
 chisel or wirebrush, although the use of a sandblast is prefer- 
 able. The joint sections should be separated by a free distance 
 of about J in. in order that the bottom of the V may be acces- 
 sible to the welder. 
 
 The scarf angle and free distance vary inversely. Both 
 are determined by the depth of the V. If the character of the 
 work is such that it is not practicable to separate the joint 
 sections, the V should be cut at the bottom to form a 90-dcg. 
 angle, this angle being reduced to 60 deg. as the surface is 
 approached; otherwise the scarf angle may be reduced along 
 the entire length to 60 deg., excepting in the case of very deep 
 
TRAINING ARC WELDERS 61 
 
 welds. It is usual practice now to scarf plate welds to 60 deg. 
 and separate the sections -J in. for V's up to \ in. in depth. 
 
 At the left in Fig. 43 is shown the poor fusion obtained 
 at the bottom of the V on welding a 1-in. square bar, scarfed 
 60 deg., without the use of a free distance. At the right is 
 shown the satisfactory union obtained with the use of free 
 distance of -J in. Whenever a butt joint is accessible to hori- 
 zontal welding from both sides, it is preferable to scarf the 
 sections to a double-bevel, double-V joint. 
 
 The choice of arc current is determined by the thermal 
 conductivity and capacity of the joint as previously discussed, 
 a convenient criterion being the depth of arc crater. The 
 arc current selected should be of such a value that on welding 
 the given sections the depth of the arc crater or "bite" is 
 never less than Y 16 in - 
 
 Electrode Current Density. To maintain a uniform flow 
 of the metal, neither too slow, which causes excessive penetra- 
 tion, nor too fast, which produces excessive overlap, an elec- 
 trode diameter should be chosen such that the current density 
 is approximately 8,000 amp. per square inch. For the usual 
 sizes of bare wire available this corresponds to the following 
 welding currents : 
 
 r Arc Current (Amp.) \ Electrode 
 
 Normal Maximum Minimum Diameter (in.) 
 
 225 275 190 3/16 
 
 155 190 125 5/32 
 
 100 125 70 1/8 
 
 60 70 45 3/32 
 
 If covered electrodes are used, the direct-current rating for 
 the wires should be decreased roughly to 60 per cent of these 
 values. If bare wires are used on alternating current, the 
 rating should be increased from 20 to 40 per cent. 
 
 The first layer should thoroughly fuse the apex of the V. 
 Wherever possible inspect the reverse side, as the deposited 
 metal should appear projecting through. Subsequent layers 
 should be fused then to the preceding layers or to the scarfed 
 face. The final surface should be from Vie to 1 / 8 in. above 
 that of the adjacent sections. This welt increases the strength 
 of the joint or permits the joint surface to be machined to a 
 smooth finish. If the weld is to be oil-tight, the metal project- 
 
62 ELECTRIC WELDING 
 
 ing through the abutting sections on the reverse side as a result 
 of the first step in filling the section should be chipped out 
 and the resulting groove filled with at least one layer of 
 deposited metal. This extension of the procedure is frequently 
 used in the welding of double-bevel joints where the joint is 
 to have a "100 per cent" strength. 
 
 If a vertical seam is to be welded, sufficient material should 
 first be deposited to produce a shoulder so that the added 
 metal may be applied on an almost horizontal surface to facili- 
 tate the welding operation, 
 
 If an overhead seam is to be welded, the operation is sim- 
 plified by placing on the upper side of the joint a heavy steel 
 plate covering the apex of the V. A shoulder is then formed 
 by an initial deposit of metal, the operator continuing to add 
 metal to the corner so produced and the vertical face of the 
 shoulder. 
 
 The considerations pointed out under the section on thermal 
 characteristics determine whether it is necessary to preheat 
 and anneal the joint. The method used in filling the scarfed 
 section is determined by the preference for either the rigid or 
 non-rigid system. 
 
 When using the rigid system both sections of the joint are 
 clamped firmly to prevent either member from moving under 
 the stresses produced by the expansion and contraction ob- 
 tained during the welding operation. If a proper welding 
 sequence is not followed, the accumulation of "locked-in" 
 stresses on cooling may be sufficient to rupture the welded 
 area. To minimize these stresses it is the usual practice to 
 tack the plates together at the apex of the scarf with short 
 deposits at about 1-ft. intervals, and then to deposit single 
 layers in alternate gaps, each tier being completed before add- 
 ing a second tier at any section. This procedure tends to 
 maintain a low average temperature of the joint and plate, 
 thereby decreasing the amount of expansion, while the deposi- 
 tion of the metal in layers serves partly to anneal the metal 
 beneath and materially reduce "locked-in" stresses. 
 
 In the non-rigid system both members of the joint are free 
 to move. To prevent the edges of the plate from overlapping 
 or touching as shown in Fig. 42, the initial free distance is made 
 great enough to equalize the movement of the plates caused 
 
TRAINING ARC WELDERS 63 
 
 by the contraction of the hot deposited metal. On welding 
 long seams of J-in. plate the contraction is limited by main- 
 taining a spacing block 5 /ie i n - wide, approximately 1 ft. ahead 
 of the welded section. With a "free distance" of J in. the 
 contraction stresses draw the plates together a distance of 
 3 / 10 in. This modification converts the non-rigid into a semi- 
 rigid system. 
 
 Inspection. No direct, non-destructive means are available 
 for readily determining the strength and ductility of welds. 
 A number of indirect methods, however, are in commercial 
 use which give a fair measure of weld characteristics if intel- 
 ligently applied. They consist in estimating the degree of 
 fusion and porosity present by critically inspecting the surface 
 of each layer and in noting the depth of liquid penetration 
 through the completed section. 
 
 In examining each layer the amount of oxide present, 
 smoothness and regularity of the surface, its contour, freedom 
 from porosity and depth of crater should be noted. After a 
 little experience these observations will give the inspector a 
 good indication of the manipulative ability of the welder and 
 of the degree of fusion obtained, as discussed above. 
 
 A succession of unfused zones will produce a leaky joint. 
 These sections may be detected by flooding one surface of 
 the joint with kerosene, using a retaining wall of putty, if 
 necessary, as the liquid penetrates through the linked areas 
 and emerges to stain the opposite side. 
 
 Brief Terminology. The following terms are used most 
 frequently in arc welding: 
 
 Free distance. The amount that the joint sections are separated before 
 welding. 
 
 Overlap. The area of deposited metal that is not fused to the parent 
 metal. 
 
 Parent metal. The original metal of the joint sections. 
 
 Penetration. The depth to which the parent metal is melted by the arc 
 gaged by the depth of the arc crater. 
 
 Recession. The distance between the original scarf line and the average 
 depth of penetration parallel to this line obtained in the completed weld. 
 
 Ee-entrant angle. The angle between the original surface of the parent 
 metal and the overlapping, unfused deposit edge. 
 
 Scarf. The chamfered surface of a joint. 
 
 Tack. A short deposit, from to 2 in. long, which serves to hold 
 the sections of a joint in place. 
 
64 ELECTRIC WELDING 
 
 Weaving. A semi-circular motion of the arc terminal to the right and 
 left of the direction of deposition, which serves to increase the width of 
 the deposit, decrease overlap and assist in slag flotation. 
 
 Welt. The material extending beyond the surface of the weld shanks 
 to reinforce the weld. 
 
 QUESTIONS AND ANSWERS 
 
 What does the welder's equipment consist of? 
 
 Welding generator, electrode holder with cables, welding booth, helmet 
 or shield, gauntlets, high shoes with bellows tongue, heavy clothing or 
 leather apron, proper electrodes. 
 
 What is the most important precaution the operator should observe? 
 
 To protect his eyes and body from the radiant energy emitted by the 
 arc. 
 
 How is the operator prevented from drawing too long an arc after 
 the electrode "freezes" to the work? 
 
 By twisting the wrist sharply to tho right or left, thereby shearing the 
 fused area. 
 
 What is the essential factor in securing the maintenance of the arc? 
 
 The electrode should be advanced to the work at the rate at which it 
 is being melted. 
 
 What is the test of an operator's manipulative ability? 
 
 He should be able to hold an arc no longer than J in., having a voltage 
 across it less than twenty-five during the period required to deposit the 
 metal from a 6 / 32 -in. diameter bare electrode, 12 in. long on 150 amp. 
 direct current. 
 
 What is meant by "free distance," "overlap," "parent metal," 
 "penetration," "recession," "re-entrant angle," "scarf," "tack," 
 "weaving" and "welt"? 
 
 Given under ' ' Terminology. ' ' 
 
 What function does the arc perform? 
 
 It transforms electrical energy into Thermal energy. 
 
 What polarity should the welder use on welding all but thin sections 
 with bare electrodes? 
 
 The pencil electrode should be negative. 
 
 How may the amount of oxide formed be reduced to a minimum? 
 
 By holding a short arc and the use of electrodes containing a small 
 quantity of carbon (0.18 per cent) and manganese (0.50 per cent). 
 
 How may an operator determine the degree of fusion obtained (a) by 
 inspecting the surface, (b) by inspecting the cross-section of deposit? 
 
 (a) By examining the contour of the surface, noting the re-entrant 
 angle and estimating the overlap; observing the depth of crater and 
 estimating the penetration. 
 
 (b) By directly observing the depth of penetration of recession, the 
 overlap and porosity or blow holes. 
 
 What are the factors in arc welding that determine the degree of 
 fusion? 
 
TRAINING ARC WELDERS 65 
 
 Arc current, arc length, electrode current density, electrode material, 
 freedom of weld from oxides. 
 
 How may a welder determine when he is using the proper welding 
 current ? 
 
 By the depth the arc melts the material welded. The crater should 
 be not less than y 16 in. in depth. 
 
 What is the most important thermal characteristic encountered in 
 welding? 
 
 Contraction of the hot deposit. 
 
 How may strains produced by this characteristic be minimized? 
 
 By adopting a correct welding procedure, either non-rigid or rigid, 
 which serves partly to anneal the metal and reduce "locked-in" stresses. 
 
 What is the effect of holding too long an arc with the metallic electrode? 
 
 The use of a long arc produces a poor deposit, due to insufficient 
 penetration, and also produces a large amount of oxide which reduces both 
 the strength and ductility of the joint. 
 
 What size of bare electrodes corresponds to welding currents of 
 approximately 225, 155, 100 and 60 amp. on welding with direct current? 
 
 Sizes 3 / 16 , s / 32 , 1 / 8 and 3 / 32 in. respectively. 
 
 How should joint sections be prepared for welding? 
 
 The surfaces should be cleaned thoroughly and the faces of the joint 
 scarfed to an angle of 60 to 90 degrees with the edges separated a free 
 distance of approximately | in. in the rigid welding process, and an addi- 
 tional 3 / 16 in. per foot from the point welded for each foot length when 
 using the non-rigid system. 
 
 What surface characteristics denote fusion? 
 
 Surface porosity, amount of oxide coating, depth of arc crater, surface 
 contour, compactness, regularity and re-entrant angles. 
 
CHAPTER V 
 CARBON-ELECTRODE ARC WELDING AND CUTTING 
 
 In the American Machinist of Sept. 9, 1920, O. H. Escholz, 
 research engineer of the Westinghouse Electric & Manufac- 
 turing Co., dealt with the various phases of carbon arc welding 
 and cutting as follows: 
 
 Carbon or graphite electrode arc welding is the oldest of 
 the electric fusion arc processes now in use. The original 
 process consisted in drawing an arc between the parent metal 
 and a carbon electrode in such a manner that the thermal 
 energy developed at the metal crater fused together the edges 
 of the joint members. This process was early modified by add- 
 ing fused filling metal to the molten^ surface of the parent 
 metal. 
 
 The equipment now used consists of a direct-current arc- 
 circuit possessing inherent means for stabilizing the carbon 
 arc, a welding hood for the operator, an electrode holder that 
 does not become uncomfortably hot in service and suitable 
 clothing such as bellows-tongued shoes, gauntlets and apron of 
 heavy material. 
 
 When arc currents of less than 200 amp. are used, or when 
 a graphite arc process is employed intermittently with the 
 metallic electrode process, the carbon-holding adapter shown 
 in Fig. 44 may be used with the metallic electrode holder, the 
 shank of the adapter being substituted for the metal electrode. 
 With very high arc currents, 750 amp. or more, special holders 
 should He constructed to protect the operator from the intense 
 heat generated at the arc. Typical holders are shown in Figs. 
 45 and 46. 
 
 Electrodes. Although hard carbon was originally employed 
 for the electrode material, experience has shown that a lower 
 rate of electrode consumption as well as a softer weld may be 
 obtained by substituting graphite electrodes. While both elec- 
 
 66 
 
CARBON-ELECTRODE ARC WELDING AND CUTTING 67 
 
 trodcs have the same base and binder, the graphite electrode 
 is baked at a sufficiently high temperature (2000 deg. C.) to 
 graphitize the binder, thereby improving the bond and the 
 homogeneity of the electrode. The graphite electrode is readily 
 
 FIG. 44. Adapters for Using Carbons in Metallic-Electrode Holder 
 
 FIG. 45. Metallic-Electrode Holder. 
 
 FIG. 46. Carbon- or Graphite-Electrode Holder. 
 
 distinguishable by its greasy "feel" and the characteristic 
 streak it makes on paper. 
 
 The diameter of the electrode is determined partly by the 
 arc current. To fix the position of the carbon arc terminal, 
 
68 ELECTRIC WELDING 
 
 thereby increasing arc stability and arc control, all electrodes 
 should be tapered. This precaution is particularly important 
 when using low valujs of arc current or when maintaining an 
 arc under conditions which cause distortion and instability. 
 The following table gives electrode diameters in most common 
 use with various arc currents : 
 
 Amperes Diameter 
 
 50 to 150 i in. tapered to | in. 
 
 150 to 300 | in. tapered to g in. 
 
 300 to 500 1 in. tapered to | in. 
 
 500 to 750 1^ in. tapered to | in. 
 
 750 to 1000 H in. tapered to } in. 
 
 Filler Material. A strong, sound weld can be obtained only 
 by using for filler metal low-carbon, commercially pure iron 
 rods having a diameter of f in. or \ in., depending on the 
 welding current used. Cast iron or manganese steel filler rods 
 produce hard welds in which the fusion between the parent 
 and added metals may be incomplete. Short rods of scrap 
 metal, steel turnings, etc., are frequently made use of for filler 
 metal when the purpose of the welder is merely to fill a hole 
 as rapidly as possible. It should be understood that welds 
 made with such metal are weak, contain many blowholes and 
 are frequently too hard to machine. 
 
 It is as difficult for the user of graphite arc processes as 
 it is for the oxy-acetylene welder to estimate the degree of 
 fusion obtained between deposited and parent metals. There- 
 fore the operator must follow conscientiously the correct pro- 
 cedure, recognizing that the responsibility of executing a faulty 
 weld rests solely with himself. He should, of course, have a 
 working knowledge of metals, must be able to distinguish 
 colors and possess a fair degree of muscular co-ordination, 
 although the manipulative skill required is less than that neces- 
 sitated by the metallic electrode process. 
 
 For graphite arc welding employing a filler the correct 
 posture is illustrated in Fig. 47. The filler rod is shown grasped 
 by the left hand with the thumb uppermost. When held in 
 this position the welder may use the rod to brush off slag 
 from the surface of molten metal or to advance the rod into 
 the arc stream. 
 
 The surfaces to be welded should be chipped clean. Where 
 
CARBON-ELECTRODE ARC WELDING AND CUTTING 69 
 
 they are scarfed the angle should be wide enough to enable the 
 operator to draw an are from any point without danger of 
 short-circuiting the arc. It is the practice of some welders 
 to remove sand and slag from the metal surfaces by fusing 
 them with the aid of the arc and then striking the fluid mass 
 with a ball-peen hammer. This method should be discouraged 
 since both operator and nearby workmen may be seriously 
 injured by the flying hot particles. 
 
 Arc Manipulation. The arc is formed by withdrawing the 
 graphite electrode from a clean surface of solid metal or from 
 the end of the filler rod when it is held in contact with the 
 
 m m m BL.J1 
 
 FlG. 47. Correct Welding Position when Using Carbon Arc and a Filler Rod. 
 
 j . 
 
 parent metal. If the arc is formed from the surface of the 
 deposited metal or from that of a molten area, slag particles 
 may adhere to the end of the electrode, deflecting the arc and 
 increasing tfie difficulty of manipulating it. 
 
 By inclining the electrode approximately 15 deg. to the 
 vertical the control of the position, direction and speed of the 
 arc terminal is facilitated. When the electrode is held ver- 
 tically irregularities in the direction and force of convection 
 currents deflect the arc first to one side and then to another, 
 causing a corresponding movement of the metal arc terminal. 
 By inclining the graphite electrode the deflecting force is con- 
 stant in direction, with the result that the electrode arc stream 
 
70 
 
 ELECTRIC WELDING 
 
 and arc terminal remain approximately in line, as shown in 
 Pig. 48, and may then be moved in any direction or at any 
 speed by a corresponding movement of the graphite electrode. 
 Polarity. It is common knowledge that the positive 
 terminal of a carbon arc is hotter and consumes more energy 
 than the negative terminal. If the graphite electrode of the 
 welding arc is made the positive terminal, energy will be use- 
 
 GRAPHITE 
 I^Diam. Negative 
 
 Core, White 
 i-Arc Sfream, Blue 
 
 !'/ Arc F/ctme, 
 ' 
 
 PARENT METAL 
 Positive 
 
 Fie. 48. Position of Electrode and Characteristics of the Arc. 
 
 lessly consumed and the resulting higher temperature will 
 increase the loss of carbon through excessive oxidation and 
 vaporization. Moreover, for reasons well known to those 
 familiar with the phenomena of arc formation, a very unstable 
 arc is obtained with the iron parent metal functioning as the 
 negative electrode. The graphite electrode should therefore 
 always be connected to the negative terminal, reversal of 
 
CARBON-ELECTRODE ARC WELDING AND CUTTING 71 
 
 polarity being detected when the arc is difficult to hold and 
 when the carbon becomes excessively hot. 
 
 Arc Length. Even when the graphite electrode serves as 
 the negative arc terminal, its temperature is great enough to 
 cause vaporization of a considerable quantity of carbon. If 
 this carbon is permitted to be transferred to and absorbed 
 by the fluid metal, a hard weld will result. To insure a soft 
 metal practically all of the volatilized carbon should be oxid- 
 ized. This may be accomplished by regulating the arc length 
 so that atmospheric oxygen will have ample time to diffuse 
 through the arc stream and combine with all of the carbon 
 present. The correct arc length is dependent upon the welding 
 current and the degree of confinement of the arc. Since the 
 arc diameter varies as the square root of the current the arc 
 length should be increased in proportion to the square root of 
 the current. It is also obvious that when an arc is drawn 
 from a flat, open surface the vaporized carbon is more acces- 
 sible to the atmospheric gases than when it is inclosed by the 
 walls of a blowhole. This means that to secure the same amount 
 of oxidized carbon under both conditions the confined arc 
 should be the longer. Many welders are not familiar with 
 this phenomenon, with the result that metal deposited in holes 
 or corners appears to be inexplicably hard. 
 
 The length of a 250-amp. arc should not be less than \ in. 
 and that for a 500-amp. arc should not be less than J in. when 
 drawing the arc from a flat surface. The maintenance of 
 excessive arc lengths causes the diffusion, through convection 
 currents, of the protecting envelope of carbon dioxide, with 
 the result that the exposed hot metal is rapidly oxidized or 
 "burned." For most purposes a 250-amp. arc should not 
 exceed a "length of 1 in. and the length of a 500-amp. arc should 
 not exceed \\ in. In view of the large variation permissible, 
 the welder should be able to maintain an arc length which 
 assures a soft weld metal with but little slag content. 
 
 The arc serves to transform electrical energy into thermal 
 energy. The energy developed at the metal terminal or arc 
 crater is utilized to melt the parent metal, while that generated 
 in the arc stream serves to melt the filling material. If the 
 molten filler is not properly guided and, as a consequence, 
 overruns the fused parent metal, a poor weld will result. This 
 
72 ELECTRIC WELDING 
 
 process necessitates, therefore, a constant observation of the 
 distribution of the fused metals as well as a proper control 
 of the direction of flow and speed of deposition of the filling 
 metal. 
 
 There are two methods in use for adding the filler with a 
 
 FIG. 49. Starting to Build Up a Surface. 
 
 minimum overlap. One is called the "puddling" process. It 
 consists in melting a small area of the parent metal, thrusting 
 the end of the filler rod into the arc stream, where a small 
 section is melted or cut off, withdrawing the rod and fusing 
 the added material with the molten parent metal by imparting 
 
 FlG. 50. Building-Up Process Nearly Completed. 
 
 a rotary motion to the arc. This puddling of the metals serves 
 also to float slag and oxidized material to the edge of the 
 fused area, where they may be brushed or chipped off. 
 
 The rapid building up of a surface by this method is shown 
 in Fig. 49. The short sections of filler rod were welded to 
 
CARBON-ELECTRODE ARC WELDING AND CUTTING 73 
 
 the sides of the casting in order to prevent the molten material 
 from overflowing and to indicate the required height of the 
 addition. The appearance of the nearly completed "fill" is 
 shown in Fig. 50. One side of the added metal is lower than 
 the others to facilitate the floating off of the slag, some of 
 
 FIG. 51. Section Through a Built-Up Weld. 
 
 FIG. 52. Method of Depositing Filling Material in Layers. 
 
 which may be observed adhering to the edge of the plate. 
 Fig. 51 shows a section through a weld produced in this man- 
 ner, the continuous line indicating the zone of fusion and the 
 broken line the boundary of crystal structural change produced 
 by the temperature cycle through which the parent metal has 
 passed as a result of the absorption of the arc energy. 
 
74 
 
 ELECTRIC WELDING 
 
 Some users of this method advocate puddling short sections 
 of the filler rod, 1 to 3 in. in length, with the parent metal. 
 Where this is done, the filler may be incompletely fused and 
 therefore not welded to the surface of the parent metal. 
 
 In the second method the filler material is deposited in 
 
 FIG. 53. Layers of Deposits Smoothed Over. 
 
 FIG. 54. Fused Ends of Filler Rods. 
 
 layers, as shown in Figs. 52 and 53, the deposits being similar 
 to those obtained with the metallic electrode process but wider 
 and higher. In these examples a welding current of 250 amp. 
 with a filling rod f in. in dia. were used. This method simply 
 requires the operator to feed the filling rod continuously into 
 the arc stream so that the molten filler deposits on the area 
 
CARBON-ELECTRODE ARC WELDING AND CUTTING 75 
 
 of parent metal fused by the arc terminal while the arc travels 
 across the surface. If the end of the rod is moved forward 
 while resting on the surface of the newly deposited metal, 
 
 FIG. 55. Showing the Fusion of Parent Metal and Four Layers. 
 
 most of the slag produced by the oxidation of the hot metal 
 is floated to the sides of the deposit, where it may be brushed 
 or chipped off. 
 
 The appearance of fused filler rod ends when correctly 
 manipulated is shown in Fig. 54. Slag may be observed still 
 
 Fie. 56. Flanged Edges Welded with Graphite Arc. 
 
 adhering to the bottom of one of the rods. The fusion between 
 parent and added metal is shown in Fig. 55. Four layers of 
 added metal are shown at the upper surface. 
 
 To remove slag or improve the appearance of the deposits 
 
76 ELECTRIC WELDING 
 
 the surface of the added metal may be remelted by running 
 the arc terminal over it, provided "burning" and hardening 
 of the metal is avoided. Figs. 52 and 53 illustrate plainly the 
 appearance of deposits before and after the surfacing operation. 
 
 The expedient of hammering or swaging the hot deposited 
 metal is frequently resorted to where a refinement in the struc- 
 ture of the crystal grains is desirable. 
 
 Flanged Seam Welding. Fig. 56 illustrates a useful appli- 
 cation of the original carbon-arc process wherein no filler metal 
 is used, the metal arc terminal serving to melt together the 
 flanged edges. 
 
 This process is easily performed. To obtain adequate fusion 
 the arc current selected should have such a value that the 
 metal-arc crater nearly spans the edges of the seam. To assure 
 the maintenance of a stable arc a small, tapered electrode 
 should be employed, the diameter of the electrode end remain- 
 ing less than |-in. during use. 
 
 This graphite arc process is used occasionally to form butt 
 and lap welds by melting together the sides of the joint without 
 the use of filler metal. Examination of sections through joints 
 made in this manner reveals that the weld is very shallow and 
 therefore weak. 
 
 Welding of Non-Ferrous Metals. Copper and bronzes have 
 been successfully welded with the graphite arc when employ- 
 ing a bronze filler rod low in tin and zinc and high in phos- 
 phorous, at least 0.25 per cent. The best filler material for 
 the various analyses of parent metals has not been determined, 
 but it is recognized that the presence of some deoxidizing agent 
 such as phosphorus is necessary in order to insure sound welds 
 free from oxide and blowholes. Since copper and its alloys 
 have a high thermal capacity and conductivity, preheating of 
 the structure facilitates the fusion of the joint surfaces. The 
 grain of the completed weld may be refined by subjecting the 
 metal to a suitable mechanical working and temperature cycle. 
 
 Low-melting-point metals such as lead may be welded by 
 holding the graphite electrode in contact with the surfaces to 
 be fused without drawing an arc, the current value used being 
 sufficient to heat the end of the carbon to incandescence. The 
 hot electrode tip may also be used to melt the filler rod into 
 the molten parent metal. 
 
CARBON-ELECTRODE ARC WELDING AND CUTTING 77 
 
 Application. The graphite arc processes may be used for 
 the following purposes: 
 
 (1) Welding of cast steel and non-ferrous metals. 
 
 (2) Cutting of cast-iron and cast-steel risers and fins and 
 non-ferrous metals. 
 
 (3) Rapid deposition of metal to build up a surface or fill 
 in shrinkage cavities, cracks, blowholes and sand pockets where 
 strength is of minor importance. 
 
 (4) Fusion of standing seams. 
 
 (5) Melting and cutting of scrap metal. 
 
 (6) Remelting of a surface to improve its appearance or fit. 
 
 FIG. 57. Typical Carbon-Electrode Cuts in -In. Ship Plate. 
 
 (7) Preheating of a metal structure to facilitate the welding 
 operation, to reduce locked-in stresses or to alter some 
 dimension. 
 
 (8) Deposition of hard metal or the hardening of a surface 
 by the inclusion of vaporized carbon, such as rails, frogs and 
 wheel treads. 
 
 (9) Automatic cutting and welding of sheet metal. 
 Cutting. The manipulation of the cutting arc is exceed- 
 
 ingly simple, the operator merely advancing the arc terminal 
 over the section to be cut at a rate equal to that at which 
 the molten metal flows from the cut. The cutting speed in- 
 
78 ELECTRIC WELDING 
 
 creases with the value of arc current used. The width of the 
 cut increases with the arc diameter and therefore as the square 
 root of the arc current. Fig. 57 shows the appearance of cuts 
 made in ship steel plate in. thick. The following data apply 
 in this case : 
 
 Position of Cut Amp. Width, in. Length, in. Time, min. 
 
 Upper 250 0.5 8 2 
 
 Lower 650 0.8 8 1 
 
 Before cutting this plate the welder outlined the desired 
 course of the cut by a series of prick-punch marks. 
 
 When cutting deeper than 4 in. the electrode should not 
 come in contact with the walls of the cut and thereby short- 
 circuit the arc. 
 
 This process may be used for cutting both ferrous and non- 
 ferrous metals. It has found a particularly useful field in the 
 cutting of cast iron. It is often used for the " burning " out 
 of blast-furnace tap holes and the melting or cutting of iron 
 frozen in such furnaces. 
 
 CUTTING METALS 
 
 The accompanying charts illustrate the application of the 
 carbon electrode cutting process with a current value of 350 
 to 800 amperes, depending on the thickness of the metal and 
 the speed of cutting desired. A moderate cutting speed is 
 obtained at a small operating expense, adapting it particularly 
 for use in foundries for cutting off risers, sink heads, for cut- 
 ting up scrap, and general work of this nature where a smooth 
 finish cut is not essential. 
 
 The cross section of these risers, etc., is frequently of con- 
 siderable area, but by the use of the proper current value, 
 they may be readily removed. 
 
 Table IV shows the results obtained from tests in cutting 
 steel plate with the electric arc. The curves show the rate 
 of cutting cast iron sections of various shapes. Fig. 58 shows 
 the rate of cutting cast iron plates. Fig. 59 circular cross 
 sections, and Fig. 60 square blocks. The curves are based on 
 data secured through an extensive series of observations. 
 
CARBON-ELECTRODE ARC WELDING AND CUTTING 79 
 
 FIG. 58. Eate of Cutting Cast Iron Plates. 
 
 10 20 30 40 50 60 70 SO 
 
 I I 1-M.ntatcs | | | | 
 
 FIG. 59. Rate of Cutting Cast Iron of Circular Cross Section. 
 
 
 
 
 
 
 
 
 
 
 
 
 -^ 
 
 ^ 
 
 *^^ 
 
 
 
 
 
 
 
 
 
 \^^ 
 
 ^ 
 
 ,x^ 
 
 
 
 
 
 
 
 
 
 
 ^ 
 
 ^ 
 
 
 
 
 
 
 
 
 
 
 
 x 
 
 ^ 
 
 
 
 
 
 
 
 
 
 L] 
 
 
 X 
 
 X 
 
 
 
 
 
 
 
 
 
 
 
 <* 8 
 lA 
 
 / 
 
 
 
 
 
 
 
 
 
 
 
 
 
 rh 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 r~i 
 
 9 2 
 
 3 
 
 4 
 
 5 
 
 6 
 1 
 
 7 
 
 hinute 
 
 o a 
 
 1 
 
 9 
 
 9 1( 
 
 K) 1 
 
 1. 
 
 20 1 
 
 30 
 
 Fie. 60. Rate of Cutting Cast Iron Square Blocks. 
 
80 ELECTRIC WELDING 
 
 TABLE IV. CUTTING STEEL PLATES WITH THE CARBON ARC 
 
 Thickness 
 
 Current 
 
 Speed Minutes 
 
 
 in Inches 
 
 in Amps. 
 
 Per Ft. 
 
 Kw.-Hrs. Per Ft. 
 
 1 
 
 400 
 
 .50 
 
 .312 
 
 i 
 
 400 
 
 1.20 
 
 .75 
 
 1 
 
 400 
 
 2.14 
 
 1.34 
 
 1 
 
 400 
 
 3.00 
 
 1.88 
 
 1 
 
 600 
 
 3.75 
 
 3.50 
 
 H 
 
 600 
 
 4.32 
 
 4.10 
 
 2 
 
 600 
 
 6.75 
 
 6.30 
 
 4 
 
 600 
 
 16.90 
 
 15.50 
 
 6 
 
 800 
 
 29.00 
 
 36.20 
 
 8 
 
 800 
 
 40.50 
 
 50.00 
 
 10 
 
 800 
 
 59.00 
 
 74.00 
 
 12 
 
 800 
 
 65.00 
 
 82.00 
 
CHAPTER VI 
 ARC WELDING PROCEDURE 
 
 It is presumed that the welder has a fair knowledge of 
 the different processes of both carbon and metallic arc weld- 
 ing, gained from reading the previous chapters or from actual 
 experience. However, we will recapitulate to some extent 
 in order to make everything as clear as possible. Then we shall 
 give some examples of the proper procedure in making welds 
 of various kinds. For the descriptions and drawings we are 
 principally indebted to the Westinghouse Electric and Manu- 
 facturing Co., the Lincoln Electric Co., and the Wilson Welder 
 and Metals Co. 
 
 In order to prepare the metal for a satisfactory weld, the 
 entire surfaces to be welded must be made readily accessible 
 to the deposit of the new metal which is to be added. In 
 addition, it is very essential that the surfaces are free from 
 dirt, grease, sand, rust or other foreign matter. For this 
 service, a sandblast, metal wire brush, or cold chisel are recom- 
 mended. 
 
 During the past few years great progress has been made 
 in the improvement of steels by the proper correlation of 
 heat treatment and chemical composition. The characteristics 
 of high-carbon and alloy steels, particularly, have been radically 
 improved. However, no amount of heat treatment will appre- 
 ciably improve or change the characteristics of medium and 
 low-carbon steels which comprise the greatest field of applica- 
 tion for arc welding. Furthermore, the metal usually deposited 
 by the arc is a low-carbon steel often approaching commercially 
 pure iron. It must be evident therefore that the changes of 
 steel structure due to the arc-welding process will not be 
 appreciable and also that any subsequent heat treatment of 
 the medium- or mild-steel material will not result in improve- 
 ments commensurate with the cost. 
 
 81 
 
82 ELECTRIC WELDING 
 
 Pre-heating of medium and mild steel before applying the 
 arc is not necessary and will only enable the operator to make 
 a weld with a lesser value of current. 
 
 Cast-iron welds must be annealed before machining other 
 than grinding is done in the welded sections. This is necessary 
 because at the boundary between the original cast iron and 
 the deposited metal there will be formed a zone of hard, high- 
 carbon steel produced by the union of carbon (from the cast 
 iron) with the iron filler. This material is chilled quite sud- 
 denly after the weld is made by the dissipation of the heat 
 into the surrounding cast iron which is usually at a com- 
 paratively low temperature. 
 
 Although it is not absolutely necessary to pre-heat cast iron 
 previous to arc welding, this is done in some instances to 
 produce a partial annealing of the finished weld. The pre- 
 heating operation will raise the temperature of a large portion 
 of the casting. When the weld is completed, the heat in the 
 casting will flow into the welded section, thereby reducing the 
 rate of cooling. 
 
 Arc Length. The maintenance of the proper arc length for 
 the metallic electrode process is very important. With a long 
 arc an extended surface of the work is covered probably caused 
 by air drafts with the result that there is only a thin deposit 
 of the new metal with poor fusion. If, however, the arc is 
 maintained short, much better fusion is obtained, the new 
 metal will be confined to a smaller area, and the burning and 
 porosity of the fused metal will be reduced by the greater 
 protection from atmospheric oxygen afforded by the envelop- 
 ing inert gases. With increase in arc length, the flame becomes 
 harder to control, so that it is impossible to adequately protect 
 the deposited metal from oxidation. 
 
 The arc length should be uniform and just as short as it is 
 possible for a good welder to maintain it. Under good normal 
 conditions the arc length is such that the arc voltage never 
 exceeds 25 volts and the best results are obtained between 
 18 and 22 volts. For an arc of 175 amp. the actual gap will 
 be aboat -J inch. 
 
 Manipulation of the Arc. The arc is established by touch- 
 ing the electrode to the work, and drawing it away to ap- 
 proximately J in., in the case of the metallic electrode. This 
 
ARC WELDING PROCEDURE 83 
 
 is best done by a dragging touch with the electrode slightly 
 out of vertical. The electrode is then held approximately at 
 right angles to the surface of the work, as the tendency is 
 for the heat to go straight from the end of the electrode. This 
 assures the fusing of the work, provided the proper current 
 and arc length have been uniformly maintained. 
 
 A slight semicircular motion of the electrode, which at the 
 same time is moved along the groove, will tend to float the 
 slag to the top better than if the electrode is moved along a 
 straight line in one continuous direction and the best results 
 are obtained when the welding progresses in an upward direc- 
 tion. It is necessary in making a good weld to ' ' bite ' ' into 
 the work to create a perfect fusion along the edges of the 
 weld, while the movement of the electrode is necessary for the 
 removal of any mechanical impurities that may be deposited. 
 It is the practice to collect the slag about a nucleus by this 
 
 C 
 
 FIG. 61. Diagram Illustrating Filling Sequence. 
 
 rotary movement and then float it to the edge of the weld. 
 If this cannot be done, the slag is removed by chipping or 
 brushing with a wire brush. 
 
 Filling Sequence. When making a long seam between 
 plates, the operator is always confronted with the problem 
 of expansion and contraction which cause the plates to warp 
 and produce internal strains in both plates and deposited 
 material. 
 
 The method of welding two plates together is shown in 
 Fig. 61. The plates are prepared for welding as previously 
 described, and the arc is started at the point A. The welding 
 then progresses to the point B, joining the edges together, to 
 point D and back to A. This procedure is carried on with 
 the first layer filling in a space of 6 or 8 in. in length, after- 
 ward returning for the additional layers necessary to fill the 
 groove. This method allows the entire electrode to be deposited 
 without breaking the arc, and the thin edges of the work are 
 
84 
 
 ELECTRIC WELDING 
 
 not fused away as might bo the case if the operator should 
 endeavor to join these edges by moving the electrode in- one 
 continuous direction. This method also prevents too rapid 
 chilling with consequent local strains adjacent to the weld. 
 
 When making a long seam weld, for example, a butt weld 
 between two plates, the two pieces of metal will warp and have 
 their relative positions distorted during the welding process, 
 unless the proper method is used. 
 
 A method was devised and has been successfully put into 
 operation by E. Wanamaker and H. R. Pennington, of the 
 Chicago, Rock Island and Pacific R.R. P>y their method the 
 
 FIG. 62. Diagram Illustrating Back-Step Method. 
 
 plates are fastened together by light tack welds about 8 in. 
 apart along the whole seam. The operator then makes a com- 
 plete weld between the first two tacks as described in the 
 preceding paragraph, and, skipping three spaces, welds between 
 the fifth and sixth tacks and so on until the end of the seam 
 is reached. This skipping process is repeated by starting be- 
 tween the second and third tacks and so on until the complete 
 seam is welded. The adoption of this method permits the heat, 
 in a restricted area, to be dissipated and radiated before addi- 
 tional welding is performed near that area. Thus the weld is 
 made on comparatively cool sections of the plates which keeps 
 the expansion at a minimum. 
 
ARC WELDING PROCEDURE 85 
 
 Another method very similar to the preceding one, is known 
 as the back-step method, Fig. 62, in which the weld is performed 
 in sections as in the skipping process. After the pieces are 
 tacked at intervals of 6 in. or less for short seams, the arc 
 is applied at the second tack and the groove welded back 
 complete to the first tack. Work is then begun at the third 
 tack and the weld carried back to the second tack, practically 
 completing that section. Each section is finished before start- 
 ing the next. 
 
 Fig. 63 shows the procedure of welding in a square sheet 
 or patch. Work is started at A and carried to B completely 
 welding the seam. In order that work may next be started 
 at the coolest point, the bottom seam is completed starting 
 at />, finishing at C. The next seam is A to D, starting at A. 
 
 D 
 
 FIG. 63. Diagram Illustrating Square Patch Method. 
 
 The last seam is finished, starting at 5, and completing the 
 weld at C. 
 
 Alternating- Current Arc Welding. Direct current has been 
 used for arc welding because of the fact that it possesses cer- 
 tain inherent advantages that make it especially adaptable for 
 this class of work. However, the use of alternating current 
 for arc welding has found a number of advocates. 
 
 When employing this form of energy, use is made of a trans- 
 former to reduce the distribution voltage to that suitable for 
 application to the weld. 
 
 Inasmuch as the arc voltage is obtained directly from the 
 distribution mains through a transformer, the theoretical effi- 
 ciency is high compared with the direct-current process which 
 requires the introduction of a motor- generator or resistor or 
 
86 ELECTRIC WELDING 
 
 both. The efficiency of the a.c. equipments now on the market 
 ranges from 60 to 80 per cent. The transformer, however, 
 is designed to have a large leakage reactance so as to furnish 
 stability to the arc, which very materially reduces its efficiency 
 when compared with that of the standard distribution trans- 
 former used by lighting companies. 
 
 It is difficult to maintain the alternating arc when using 
 a bare electrode though this difficulty ic somewhat relieved 
 when use is made of a coated electrode. 
 
 Quasi Arc Welding. The electrodes used in quasi arc weld- 
 ing are made by the Quasi Arc Weldtrode Co., Brooklyn, N. 
 Y., and are known as "weldtrodes." A mild-steel wire is used 
 with a very small aluminum wire running lengthwise of it. 
 Around the two is wrapped asbestos thread. This asbestos 
 thread is held on by dipping the combination into something 
 similar to waterglass. Either a.c. or d.c. may be used, at a 
 pressure of about 105 volts, with a suitable resistance for 
 regulating the current. The company's directions and claims 
 for this process are : "The bared end of the weldtrode, held in 
 a suitable holder, is connected to one pole of the current supply 
 by means of a flexible cable, the return wire being connected 
 to the work. In the case of welding small articles, the work 
 is laid on an iron plate or bench to which the return wire is 
 connected. Electrical contact is made by touching the work 
 with the end of the weldtrode held vertically, thus allowing 
 current to pass and an arc to form. The weldtrode, still kept 
 in contact with the work, is then dropped to an angle, and a 
 quasi-arc will be formed owing to the fact that the special 
 covering passes into the igneous state, and as a secondary 
 conductor maintains electrical connection between the work 
 and the metallic core of the weldtrode. The action once started, 
 the weldtrode melts at a uniform rate so long as it remains 
 in contact, and leaves a seam of metal fused into the work. 
 The covering material of the weldtrode, acting as a slag, floats 
 and spreads over the surface of the weld as it is formed. The 
 fused metal, being entirely covered by the slag, is protected 
 from oxidation. TRe slag covering is readily chipped or 
 brushed off when the weld cools, leaving a bright clean metallic 
 surface. In welding do not draw the weldtrode along the 
 seam, as it is burning away all the time, and therefore it is 
 
ARC WELDING PROCEDURE 
 
 87 
 
 only necessary to feed it down, but do this with a slightly 
 lateral movement, so as to spread the heat and deposited metal 
 equally to both sides of the joint. Care must be taken to keep 
 feeding down at the same rate as the weldtrode is melting. 
 On no account draw the weldtrode away from the work to 
 make a continuous arc as this will result in putting down 
 bad metal. The aim should be to keep the point of the weld- 
 
 After 
 
 After 
 
 After 
 
 After 
 
 After 
 
 Before 
 
 After 
 
 Before 
 
 After 
 
 After 
 
 Before 
 
 After _____ 
 
 After 
 
 After 
 TIG. 64. Typical Examples of Prepared and Finished Work. 
 
 => 
 
 trode just in the molten slag by the feel of the covering just 
 rubbing on the work. By closely observing the operation, the 
 molten metal can easily be distinguished from the molten slag, 
 the metal being dull red and the slag very bright red." 
 
 The weldtrodes are supplied ready for use in standard 
 lengths of 18 in., and of various diameters, according to the 
 size and nature of the work for which they are required. 
 
88 
 
 ELECTRIC WELDING 
 
 Typical Examples of Arc Welding. The examples of weld- 
 ing shown in Figs. 64, 65 and 66 are taken from the manual 
 issued by the Wilson Welder and Metals Co. They will be 
 found very useful as a guide for all sorts of work. Fig. 64 
 
 Before 
 
 After 
 
 Before 
 
 33 
 
 After 
 
 Before 
 
 Before 
 
 After 
 
 After 
 
 After 
 
 W" 
 
 
 
 After 
 
 After 
 
 Before 
 
 Before 
 
 After 
 
 After 
 
 After 
 
 FIG. 65. Examples of Tube Work. 
 
 shows miscellaneous plate or sheet jobs, Fig. 65 shows tube 
 jobs, while Fig. 66 gives examples of locomotive-frame and 
 boiler-tube welding. 
 
 As a basis for various welding calculations the following 
 data will be found of use: On straight-away welding the 
 
ARC WELDING PROCEDURE 
 
 89 
 
 ordinary operator with helper will actually weld about 75 per 
 cent of the time. 
 
 The average results of a vast amount of data show that an 
 
 Great care must be exercised in the preparation of 
 the frames for welding, and that the proper heat valu9 
 and we I din a metals ~pe employed tor the different 
 character or material in the frames^ to be welded 
 
 Before p ^ Before 
 Welding 1 Weld ing 
 
 After 
 Welding 
 
 --) U^^"* J ta*- -^-^' - . . -j 
 
 In welding flues by the Electric Arc process, the flue sheet and flues 
 
 Pur ruciy t'C vnrica A' inccr cf/rrerenr conairions. ine proper heat value 
 to emplcy jnd amount of me fa/ to apply must be determined in each case. 
 
 FIG. 66. Examples of Electric Welding of Locomotive Frames and 
 
 Boiler Tubes. 
 
 operator 'can deposit about 1.8 Ib. of metal per hour. This 
 rate depends largely upon whether the work is done out in 
 the open or in a special place provided in the shop. For 
 outside work such as on boats, an operator will not average 
 
90 ELECTRIC WELDING 
 
 in general more than 1.2 Ib. per hour, while in the shop the 
 same operator could easily deposit the 1.8 Ib. stated above. 
 This loss in speed for outside work is brought about largely 
 by the cooling action of the air and also somewhat by the 
 added inconvenience to the operator. The value of pounds 
 per hour given above is based on the assumption that the work 
 has been lined up and is ready for welding. On the average 
 70 per cent of the weight of electrodes is deposited in the 
 weld, 12 per cent is burned or vaporized and the remainder 
 18 per cent is wasted as short ends. 
 
 Other figures prepared by the Electric Welding Committee 
 show the possible cost of a fillet weld on a |-in. plate, using 
 a motor generator set and bare electrodes to be as follows: 
 
 Average speed of welding on continuous straight away work 5 ft. per hour 
 
 Amount of metal deposited per running foot 6 Ib. 
 
 Current 150 amps, at 20 volts = 3 kilowatts. 
 
 Motor generator eff . 50 per cent = 6 kw. -f- 5 equals 1.2 k.w.h. per 1 ft. run 
 
 1.2 k.w.h. at 3 cents per k.w.h. equals 3.6 cents per ft. 
 
 Cost of electrode 10 cents per pound and allowing 
 
 for waste ends, etc., equals 7.2 cents per ft. 
 
 Labor at 65 cents per hour equals 13.00 cents per ft. 
 
 23.8 cents per ft. 
 
 Suggestions for the Design of Welded Joints. From an 
 engineering point of view, every metallic joint whether it be 
 riveted, bolted or welded, is designed to withstand a perfectly 
 definite kind and amount of stress. An example of this is the 
 longitudinal seam in the shell of a horizontal fire-tube riveted 
 boiler. This joint is designed for tension and steam tightness 
 only and will not stand even a small amount of transverse 
 bending stress without failure by leaking. If a joint performs 
 the function for which it was designed and no more, its designer 
 has fulfilled his responsibilities and it is a good joint 
 economically. Regardless of how the joint is made the design 
 of joint which costs the least to make and which at the same 
 time performs the functions required of it, with a reasonable 
 factor of safety, is the best joint. 
 
 The limitations of the several kinds of mechanical and 
 welded joints should be thoroughly understood. 
 
 A bolted joint is expensive, is difficult to make steam- or 
 water-pressure tight, but has the distinguishing advantage that 
 
ARC WELDING PROCEDURE 91 
 
 it can be disassembled without destruction. Bolted joints which 
 are as strong as the pieces bolted together are usually imprac- 
 ticable, owing to their bulk. 
 
 Riveted joints are less expensive to make than bolted joints 
 but cannot be disassembled without destruction to the rivets. 
 A riveted joint, subject to bending stress sufficient to produce 
 appreciable deformation, will not remain steam- or water- 
 pressure tight. Riveted joints can never be made as strong 
 as the original sections because of the metal punched out to 
 form the rivet holes. 
 
 There is no elasticity in either riveted, bolted or fusion- 
 welded joints which must remain steam- or water-pressure 
 tight. Excess -material is required in the jointed sections of 
 bolted or riveted joints, owing to the weakness of the joints. 
 
 Fusion-welded joints have as a limit of tensile strength 
 the tensile strength of cast metal of a composition identical 
 to that of the joined pieces. The limit of the allowable 
 bending stress is also set by the properties of cast metal of 
 the same composition as that of the joined pieces. The reason 
 for this limitation is that on the margin of a fusion weld 
 adjacent to the pieces joined, the metal of the pieces was heated 
 and cooled without change of composition. Whatever proper- 
 ties the original metal had, due to heat or mechanical treatment, 
 are removed by this action, which invariably occurs in a fusion 
 weld. Regardless of what physical properties of the metal used 
 to form the joint may be, the strength or ability to resist 
 bending of the joint, as a whole, cannot exceed the correspond- 
 ing properties of this metal in the margin of the weld. Thus, 
 assuming that a fusion weld be made in boiler plate, having 
 a tensile strength of 62,000 pounds. Assume that nickel-steel, 
 having a tensile strength of 85,000 Ib. be used to build up the 
 joint. No advantage is gained by the excess 23,000 Ib. tensile 
 strength of the nickel-steel of the joint since the joint will 
 fail at a point close to 62,000 Ib. If appreciable bending stress 
 be applied to the joint it will fail in the margin referred to. 
 
 The elastic limit of the built-in metal is the same as its 
 ultimate strength for all practical purposes, but the ultimate 
 strength is above the elastic limit of the joined sections in 
 commercial structures. 
 
 In spite of the limitations of the fusion-welded joint it is 
 
92 ELECTRIC WELDING 
 
 possible and practicable to build up a joint in commercial steel 
 which will successfully resist any stress which will be en- 
 countered in commercial work. 
 
 The fundamental factor in the strength of a welded joint 
 is the strength of the material added by the welding process. 
 This factor depends upon the nature of the stress applied. 
 The metal added by the welding process, when subject to 
 tension, can be relied on in commercial practice to give a ten- 
 sile strength of 45,000 Ib. per square inch. This is an average 
 condition; assuming that the metal added is mild steel and 
 that the operation is properly done, the metal will have ap- 
 proximately the same strength in compression as in tension. 
 When a torsional stress is applied to a welded joint ' the 
 resultant stress is produced by a combination of bending, ten- 
 sion and compression, as well as shear. The resistance of the 
 metal to shear may be figured at 8 /io its resistance to tensile 
 stress. The metal added by the welding process, with the 
 present development in the art of welding, will stand very 
 little bending stress. A fusion-welded joint made by the elec- 
 tric-arc process must be made stiffer than the adjacent sections 
 in order that the bending stress shall not come in the joint. 
 An electric weld, when properly made, will be steam- and 
 water-pressure tight so long as bending of members of the 
 structure does not produce failure of the welded joint. 
 
 Little is known at the present time in regard to the resist- 
 ance of an electrically welded joint to dynamic stress, but 
 there is reason to believe that the resistance to this kind of 
 stress is low. However, owing to the fact that in most struc- 
 tures there is an opportunity for the members of the structure 
 to flex and reduce the strain upon the weld, this inherent weak- 
 ness of the welded joint does not interfere seriously with its 
 usefulness. 
 
 A few tests have been made of high-frequency alternating 
 stresses and it has been found that using the ordinary wire 
 electrode the welded joint fails at a comparatively small num- 
 ber of alternations. This is of little importance in most struc- 
 tures since high-frequency alternating stress Ms not often 
 encountered. 
 
 Stresses in Joints. The accompanying cuts show a number 
 of typical joints and the arrows indicate the stresses brought 
 
ARC WELDING PROCEDURE 
 
 93 
 
 FIG. 67. Joints Designed to Overcome Certain Stresses. 
 
94 
 
 ELECTRIC WELDING 
 
 to bear on them. The proper way to weld each example is 
 plainly shown. 
 
 In A, Fig. 67, it will be noted that a reinforcing plate is 
 welded to the joint to make the joint sufficiently stiff to throw 
 the bending outside the weld. 
 
 B shows a joint in straight tension. Since no transverse 
 stress occurs the heavy reinforcing of A is not required. Just 
 enough reinforcing is given the joint to make up for the defi- 
 ciency in tensile strength of the metal of the weld. 
 
 C shows another method of building up a joint that is in 
 
 FIG. 68. Plate and Angle Construction. 
 
 straight tension. It Should be noted that in both B and C 
 as much reinforcing is placed on one side of a center line 
 through the plates as is placed on the other. 
 
 The original form of lap joint such as is used in riveting 
 is shown at D. The method shown for welding this joint is 
 the only method which can be used. It cannot be recommended 
 because such a joint, when in straight tension, tends to bring 
 the center line of the plate into coincidence with the center 
 line of the stress. In so doing an excessive stress is placed on 
 the welded material. 
 
 E shows the construction used in certain large tanks where 
 
ARC WELDING PROCEDURE 
 
 95 
 
 a flanged head is backed into a cylindrical shell. The principal 
 stress to be resisted by the welded joint is that tending to 
 push the head out of the shell. The welding process indicated 
 in the figure will successfully do this. Owing to the friction 
 between the weld and the shell, the outer weld would be suffi- 
 cient to hold the weld in place for ordinary pressure. For 
 higher pressures the inside weld should be made in addition. 
 
 FIG. 69. Pipe Heading and Firebox Sheet Work. 
 
 F and G show another method of welding a flanged head 
 to the cylindrical shell. These methods are preferable to the 
 method indicated in E. G represents the recommended 
 practice. 
 
 Fig. 68 shows a plate and angle structure which might 
 be used in ship construction. The particular feature to notice 
 in the welding practice indicated, is that the vertical plates 
 do not reach the entire distance between the horizontal plates. 
 
96 ELECTRIC WELDING 
 
 This is merely a method of eliminating difficulties in welding 
 the plates to the angle. 
 
 A in Fig. 69 shows a method of welding a head into a 
 cylindrical pipe. The thickness of the head should be ap- 
 proximately twice the thickness of the wall of the pipe. The 
 extra thickness plate is to gain sufficient stiffness in the head 
 to make the stress on the welded material purely shear. The 
 pressure from the inside tends to make the head assume a 
 hemispherical shape. This would place a bending stress on 
 the welded material if the head were thin enough to give at 
 the proper pressure. 
 
 B shows a method of welding a crack in a fire-box sheet. 
 The thin plate backing introduced at the weld makes the 
 operation very much easier for the operator and produces the 
 reinforcing of the water side of the fire-box sheet which is 
 most desirable. 
 
 INSPECTION OF METALLIC ELECTRODE ARC WELDS 
 
 Determining the character of welded joints is of prime 
 importance, says 0. S. Escholz, and the lack of a satisfactory 
 method, more than any other factor, has been responsible for 
 the hesitancy among engineers of the extensive adoption of 
 arc welding. To overcome this prejudice it is desirable to 
 shape our rapidly accumulating knowledge of operation into 
 an acceptable method of inspection. 
 
 Manufactured apparatus is practically all accepted on the 
 basis of complying with a process specification rigidly enforced 
 in conjunction with the successful reaction to certain tests 
 applied to the finished product. Riveting impairs the strength 
 of the joined plates, yet with a proper layout an^d intelligent 
 inspection the completed structure possesses certain definite 
 characteristics which do not require further verification. The 
 inspector of a finished concrete structure is practically help- 
 less, and the weakest sort of construction "may be concealed 
 by a sound surface. With careful supervision, however, the 
 physical properties of the completed structure can be reliably 
 gaged to the extent that the use of concrete is justified even 
 in ship construction. With this in view, electric arc welding 
 is susceptible to even better control than obtain in either of 
 these structural operations. 
 
ARC WELDING PROCEDURE 97 
 
 The four factors which determine the physical character- 
 istics of the metallic electrode arc welds are: Fusion, slag 
 content, porosity and crystal structure. 
 
 Some of the other important methods that have been sug- 
 gested and used for indicating these characteristics are: 
 
 1. Examination of the weld by visual means to determine 
 (a) finish of the surface as an index to workmanship; (b) 
 length of deposits, which indicates the frequency of breaking 
 arc, and therefore the ability to control the arc; (c) uniformity 
 of the deposits, as an indication of the faithfulness with which 
 the filler metal is placed in position; (d) fusion of deposited 
 metal to bottom of weld scarf as shown by appearance of 
 under side of welded joint; (e) predominance of surface 
 porosity and slag. 
 
 2. The edges of the deposited layers chipped with a cold 
 chisel or calking tool to determine the relative adhesion of 
 deposit. 
 
 3. Penetration tests to indicate the linked unfused zones, 
 slag pockets and porosity by (a) X-ray penetration; (b) rate 
 of gas penetration; (c) rate of liquid penetration. 
 
 4. Electrical tests (as a result of incomplete fusion, slag 
 inclusions and porosity) showing variations in (a) electrical 
 conductivity; (b) magnetic induction. 
 
 These tests if used to the best advantage would involve their 
 application to each layer of deposited metal as well as to the 
 finished weld. This, except in unusual instances, would not 
 be required by commercial practice in which a prescribed 
 welding process is carried out. 
 
 Of the above methods the visual examination is of more 
 importance than generally admitted. Together with it the 
 chipping and calking tests are particularly useful, the latter 
 test serving to indicate gross neglect by the operator of the 
 cardinal welding principles, due to the fact that only a very 
 poor joint will respond to the tests. 
 
 The most reliable indication of the soundness of the weld 
 is offered by the penetration tests. Obviously the presence 
 of unfused oxide surfaces, slag deposits and blowholes will 
 offer a varying degree of penetration. Excellent results in 
 the testing of small samples are- made possible by the use of 
 the X-ray. However, due to the nature of the apparatus, the 
 
98 ELECTRIC WELDING 
 
 amount of time required and the difficulty of manipulating 
 and interpreting results, it can hardly be considered at tlie 
 present time as a successful means to be used on large-scale 
 production. 
 
 The rate that hydrogen or air leaks through a joint from 
 pressure above atmospheric to atmospheric, or from atmospheric 
 to partial vacuum, can readily be determined by equipment 
 that would be quite cumbersome, and the slight advantage 
 over liquid penetration in time reduction is not of sufficient 
 importance to warrant consideration for most welds. 
 
 Of the various liquids that may be applied kerosene has 
 marked advantages because of its availability, low volatility 
 and high surface tension. Due to the latter characteristics 
 kerosene sprayed on a weld surface is rapidly drawn into any 
 capillaries produced by incomplete fusion between deposited 
 metal and weld scarf, or between succeeding deposits, slag 
 inclusions, gas pockets, etc., penetrating through the weld and 
 showing the existence of an unsatisfactory structure by a stain 
 on the emerging side. A bright-red stain can be produced by 
 dissolving suitable oil-soluble dyes in the kerosene. By this 
 means the presence of faults have been found that could not 
 be detected with hydraulic pressure or other methods. 
 
 By the kerosene penetration a sequence of imperfect struc- 
 ture linked through the weld, which presents the greatest 
 hazard in welded joints, could be immediately located, but it 
 should be borne in mind that this method is not applicable 
 to the detection of isolated slag or gas pockets nor small, 
 disconnected unfused areas. It has been shown by various tests, 
 however, that a weld may contain a considerable amount of 
 distributed small imperfections, without affecting to a great 
 extent its characteristics. 
 
 If a bad fault is betrayed by the kerosene test it is advis- 
 able to burn out the metal with a carbon arc before rewelding 
 under proper supervision. By the means of sandblast, steam 
 or gasoline large quantities of kerosene are preferably removed. 
 No difficulty has been encountered on welding over a thin 
 film of the liquid. 
 
 Electrical tests, by which the homogeneity of welds is 
 determined, are still in the evolutionary stages, and many diffi- 
 culties are yet to be overcome before this test becomes feasible. 
 
ARC WELDING PROCEDURE 99 
 
 Some of these difficulties are the elimination of the effect of 
 contact differences, the influence of neighboring paths and 
 fields, and the lack of practicable, portable instruments of suffi- 
 cient sensibility for the' detection of slight variations in con- 
 ductivity or magnetic field intensity. No simple tests are 
 plausible, excepting those which involve subjecting the metal 
 to excessive stresses for determining the crystal structure. 
 Control of this phase must be determined by the experience 
 obtained from following a prescribed process. 
 
 The inspector of metallic arc electrode welds may consider 
 that through the proper use of visual, chipping and penetrating 
 tests . a more definite appraisal of the finished joint may be 
 obtained than by either riveting or concrete construction. The 
 
 r 
 
 FIG. 70. Typical Arc- weld Scarfs. 
 
 operation may be still further safeguarded by requiring rigid 
 adherence to a specified process. 
 
 Good results are assured if correct procedure is followed. 
 
 Haphazard welding can no sooner produce an acceptable 
 product than hit-or-miss weaving will make a marketable cloth. 
 It is only logical that all the steps in a manufacturing opera- 
 lion should be regulated to obtain the best results. As it is 
 most welders consider themselves pioneers in an unknown art 
 that requires the exercise of a peculiar temperament for its 
 successful evolution, and as a result welding operators enshroud 
 themselves in the halo of an expert and do their work with 
 a mystery bewildering to the untutored. Once in a while, due 
 we might say to coincidences, these " experts" obtain a good 
 weld, but more often the good weld may be attributed to the 
 friction between slightly fused, plastered deposits. 
 
 In common with all other operations metallic electrode aix, 
 
100 ELECTRIC WELDING 
 
 welding is really susceptible to analysis. Regardless of the 
 metal welded with the arc the cardinal steps are: (1) Prepara- 
 tion of weld; (2) electrode selection; (3) arc-current adjust- 
 ment; (4) arc-length maintenance, and (5) heat treatment. 
 
 Sufficient scarfing is involved in the preparation of the 
 weld, as well as the separation of the weld slants, so that the 
 entire surface is accessible to the operator with a minimum 
 amount of filling required. When necessary to avoid distortion 
 and internal stresses, owing to unequal expansion and contrac- 
 tion strains, the metal is preheated or placed so as to permit 
 the necessary movement to occur. Various types of scarfs in 
 common use are shown in Fig. 70. 
 
 The electrode selection is determined by the mass, thickness 
 
 FIG. 71. Good and Bad Welds. 
 
 and constitution of the material to be welded. An electrode 
 free from impurities and containing about 17 per cent, carbon 
 and 5 per cent, manganese has been found generally satis- 
 factory for welding low and high carbon as well as alloy steels. 
 This electrode can also be used for cast-iron and malleable-iron 
 welding, although more dependable results, having a higher 
 degree of consistency and permitting machining of welded 
 sections, can be obtained by brazing, using a copper-aluminum- 
 iron-alloy electrode and some simple flux. Successful results 
 are obtained by brazing copper and brass with this electrode. 
 The diameter of the electrode should be chosen with reference 
 to the arc current used. 
 
 A great many concerns have attempted welding with too 
 
ARC WELDING PROCEDURE 
 
 101 
 
 low an arc current and the result lias been a poorly fused 
 deposit. This is due largely to the overheating characteristics 
 of most electrode holders, or using current value, .and thus- 
 leading the operator to conclude that the cufreril^iise'd is nV 
 excess of the amount that is needed. '^;^ :> 
 
 A, Fig. 71, shows a section through one-half of air exposed 
 joint welded with the proper current, and B the effects of too 
 low a current. The homogeneity and the good fusion of the 
 one may be contrasted with the porosity and poor fusion of 
 
 ZOO 
 
 Amperes Arc Current. 
 FIG. 72. Diameters for Welding Steel Plate. 
 
 the latter. These surfaces have been etched to show the char- 
 acter of the metal and the welded zone. 
 
 The approximate values of arc current to be used for a 
 given thickness of mild-steel plate, as well as the electrode 
 diameter for a given arc current, may be taken from the curve 
 in Fig. 72. The variation in the strength of 1-in. square welded 
 joints as the welding current is increased is shown in Fig. 73. 
 
 Notwithstanding that the electrode development is still in 
 its infancy the electrodes available are giving satisfactory 
 results, but considerable strides can yet be made in the duc- 
 tility of welds, consistency in results and ease of utilizing the 
 process. 
 
 The maintenance of a short arc length is imperative. A 
 nonporous, compact, homogeneous, fused deposit on a 1-in. 
 
102 
 
 ELECTRIC WELDING 
 
 square bar from a short arc is shown in Fig. 74, A, and in B 
 
 is shown a porous, diffused deposit from a long arc. Top 
 
 .yiews of* these , welds are shown in Fig. 75. A short arc is 
 
 SO 100 ISO 
 
 Amperes Arc Current. 
 
 zoo 
 
 FIG. 73. Variation in Weld Strength with Change in Arc Current. 
 
 PIG. 74. Sectional Views of Short and Long Arc Deposits. 
 
 usually maintained by a skillful operator, as the work is thereby 
 expedited, less electrode material wasted and a better weld 
 obtained because of improved fusion, decreased slag content 
 
ARC WELDING PROCEDURE 103 
 
 and porosity. On observing the arc current and arc voltage 
 by meter deflection or from the trace of recording instruments, 
 the inspector has a continuous record of the most important 
 factors which affect weld strength, ductility, fusion, porosity, 
 etc. The use of a fixed series resistance and an automatic 
 time-lag reset switch across the arc to definitely fix both the 
 arc current and the arc voltage places these important factors 
 entirely beyond the control of the welder and under the direc- 
 tion of the more competent supervisor. 
 
 Heat Treatment and Inspection, The method of placing 
 the deposited layers plays an important part on the internal 
 strains and distortion obtained on contraction. It is possible 
 that part of these strains could be relieved by preheating and 
 
 FIG. 75. Top Views of Welds Shown in Fig. 74. 
 
 annealing as well as by the allowance made in preparation 
 for the movement of the metal. 
 
 The heat treatment of a completed weld is not a necessity, 
 particularly if it has been preheated for preparation and then 
 subjected to partial annealing. A uniform annealing of the 
 structure is desirable, even in the welding of the small sections 
 of alloy and high-carbon steels, if it is to be machined or 
 subjected to heavy vibratory stresses. 
 
 The inspector, in addition to applying the above tests to 
 the completed joint and effectively supervising the process, 
 can readily assure himself of the competency of any operator 
 by the submission of sample welds to ductility and tensile 
 tests or by simply observing the surface exposed on cutting 
 through the fused zone, grinding its face and etching with a 
 solution of 1 part concentrated nitric acid in 10 parts water. 
 
 It is confidently assumed, in view of the many resources 
 at the disposal of the welding inspector, that this method of 
 
104 ELECTRIC WELDING 
 
 obtaining joints will rapidly attain successful recognition as 
 a dependable operation to be used in structural engineering. 
 
 EFFECTS OF THE CHEMICAL COMPOSITION OF METALLIC ARC 
 WELDING ELECTRODES 
 
 In order to ascertain to what extent the chemical analysis 
 of an electrode affected the welded material in metallic arc 
 welding, says J. S. Orton, two electrodes R and W were chosen 
 of widely different chemical analyses, each 0.148 in. in diameter. 
 The R electrode was within the specifications of the Welding 
 Research Committee except that the silicon content was a little 
 high. The analyses were as follows: 
 
 R wire 
 
 C 
 
 . 17 
 
 Mn 
 57 
 
 P 
 
 007 
 
 S 
 028 
 
 Si 
 14 
 
 W wire 
 
 0.39 
 
 1.01 
 
 0.005 
 
 0.024 
 
 12 
 
 
 
 
 
 
 
 The silicon content was rather high, but inasmuch as it 
 was fairly constant in both electrodes the results are com- 
 parative. 
 
 A deposit was made on a |-in. plate by means of a metallic 
 arc, the welded section being approximately 1 ft. long, 6 in. 
 wide and 1 in. thick. The welding machine used was of a 
 well-known make, with a constant voltage of 37 volts at 130 
 amperes. The plates used for depositing the first layer were 
 machined away and two test bars were made from each elec- 
 trode, composed entirely of welded material. The ends were 
 rough-machined and about 4^ in. in the middle of the specimens 
 were finished carefully. 
 
 The physical characteristics of the plates are as shown in 
 Table V. 
 
 TABLE V. PHYSICAL CHARACTERISTICS or PLATES 
 
 
 Tensile 
 Strength 
 57,300 
 
 Elastic 
 Limit 
 43,400 
 
 Elongation 
 8.0 
 
 KA 
 
 Brinncl 
 15 3 
 
 2 
 
 56 050 
 
 50 500 
 
 6 
 
 5 9 
 
 JF-1. . . . 
 
 76 200 
 
 64000 
 
 75 
 
 13 
 
 2 
 
 72,650 
 
 60,260 
 
 5 5 
 
 7 1 
 
 
 
 
 
 
 After these bars were pulled, chemical analyses were taken 
 at various points to get the values given in Table VI. 
 
ARC WELDING PROCEDURE 
 
 105 
 
 TABLE VI. CHEMICAL ANALYSES OF SPECIMENS 
 
 E-l 
 
 C 
 0.12 
 
 Mn 
 0.23 
 
 P 
 0.012 
 
 s 
 
 0.019 
 
 Si 
 0.10 
 
 2 
 
 0.09 
 
 0.24 
 
 0.016 
 
 0.014 
 
 0.08 
 
 3 
 
 0.11 
 
 0.26 
 
 0.014 
 
 0.020 
 
 0.08 
 
 W-\ 
 
 023 
 
 84 
 
 0.014 
 
 012 
 
 02 
 
 o 
 
 , 0.20 
 
 0.80 
 
 0.014 
 
 0.014 
 
 0.05 
 
 3 
 
 0.20 
 
 0.88 
 
 0.013 
 
 0.013 
 
 0.02 
 
 
 
 
 
 
 
 Photographs of the different fractures are shown in Fig. 
 77. W-l, which gave the highest tensile strength, shows 100 
 per cent, metallic structure with a silky appearance. R-l 
 shows a coarse intergranular fracture. R-2 shows a brittle, 
 shiny crystalline fracture with a slag inclusion at the lower 
 left-hand and upper right-hand corners of the bars. W-2 
 
 FIG. 76. Fractures of Test Specimens. 
 
 shows partial crystalline and partial silky fracture. At the 
 extreme right there is a portion which is not welded. This 
 is probably the reason why W-2 did not pull as much as the 
 other. Undoubtedly, next to the chemical analysis, the quan- 
 tity of slag in the weld has the biggest bearing on the tensile 
 strength. 
 
 The structure of the test specimens is shown in the micro- 
 photographs of Fig. 77. In making these photographs, no 
 attempt was made to make a complete microanalysis of the 
 two different specimens, but rather it was intended to show 
 the general difference in structure between the two different 
 types of electrode. All of these photographs were taken at 
 150 diameters except the last two, which were taken at 100. 
 
 Photograph R-1A shows the general structure of the plate 
 welded with the R electrode. This photograph shows a large- 
 
106 
 
 ELECTRIC WELDING 
 
ARC WELDING PROCEDURE 107 
 
 grain growth and columnar structure which are characteristic 
 of electric welds. Photograph Wl-A shows the general struc- 
 ture of the plate welded with the W electrode. This shows 
 comparatively small-grain structure. The structure seems to 
 be much better than that of Rl-A. Photograph Rl-B shows 
 a portion of a test specimen which was cut out of plate Rl 
 and bent to an angle of 10 deg. It is interesting to note here 
 the opening up of the welded material adjacent to slag inclu- 
 sions. Photograph Wl-B shows a portion of a small specimen 
 cut out from sample Wl and bent to an angle of 10 deg., the 
 same as in the case of Rl-B. The welded material is opening 
 up but not in the same degree nor around the slag inclusions 
 as in the corresponding photograph Rl-B. Photograph Rl-C 
 is a profile of the fracture of the Rl sample after bending 
 through an angle of 15 deg. Photograph Wl-C shows the Wl 
 sample after being bent through an angle of 17 degrees. 
 
 It seems just as important to specify the chemical composi- 
 tion of the electrode used in metallic arc welding as it is to 
 specify the chemical composition in ordering any other type 
 of steel. 
 
 Chemical composition seems to affect the physical properties 
 in electrodes as well as other steel. 
 
 An excess of manganese seems to be needed in electrodes. 
 
 The relation between the carbon and manganese of an elec- 
 trode should be approximately one to three. 
 
 High-carbon manganese wire tends not only to improve 
 the weld on account of the amount of carbon and manganese 
 in the welded material, but also on account of the type of 
 structure which this wire lends to the deposited metal. 
 
 There is a smaller amount of oxide and slag inclusions with 
 a high-carbon manganese wire than with a comparatively low- 
 carbon manganese wire. 
 
 WELDING COMMITTEE ELECTRODES 
 
 After an exhaustive series of tests the Welding Committee 
 drew up the following tentative specification for electrodes 
 intended to be used in welding mild steel of shipbuilding 
 quality : 
 
 Chemical Composition. Carbon, not over 0.18 per cent; 
 manganese, not over 0.55 per cent; phosphorus, not over 0.05 
 
108 ELECTRIC WELDING 
 
 per cent; sulphur, not over 0.05 per cent; silicon, not over 
 0.08 per cent, 
 
 Sizes : Fraction of Inch Lbs. Per Foot Foot Per Lb. Lbs. Per 100 Ft. 
 
 1/8 0.0416 24 4.16 
 
 5/32 0.0651 15.35 6.51 
 
 3/16 0.0937 10.66 9.37 
 
 Allowable tolerance 0.006 plus or minus. 
 
 Material. The material from which the wire is manufac- 
 tured shall be made by any approved process. Material made 
 by puddling process not allowed. 
 
 Physical Properties. Wire to be of uniform homogeneous 
 structure, free from segregation, oxides, pipes, seams, etc., as 
 proven by micro-photo graphs. This wire may or may not be 
 covered. 
 
 Workmanship and Finish. (a) Electric welding wire shall 
 be of the quality and finish known as "Bright Hard" or "Soft 
 Finish." "Black Annealed" or "Bright Annealed" wire shall 
 not be supplied. (6) The surface shall be free from oil or 
 grease. 
 
 Tests. The commercial weldability of these electrodes shall 
 be determined by means of tests by an experienced operator, 
 who shall demonstrate that the wire flows smoothly and evenly 
 through the arc without any detrimental phenomena. 
 
CHAPTER VII 
 ARC WELDING TERMS AND SYMBOLS 
 
 In order to aid the standardization of the various types 
 of joints and welding operations the practice recommended 
 by the Welding Committee of the Emergency Fleet Corp., for 
 
 FIG. 78. Standard Symbols Eecommended by the Welding Committee of 
 the Emergency Fleet Corporation. 
 
 STRAP 
 
 FIG. 79. 
 
 ship work, is given. The symbol chart is shown in Fig. 78 
 and the application of special terms and symbols is individually 
 shown in Figs. 79 to 112 inclusive. 
 
 109 
 
110 
 
 ELECTRIC WELDING 
 
 FIG. 79. A Strap weld is one in which the seam of two adjoin- 
 ing plates or surfaces is reinforced by any form or shape to add 
 strength and stability to the joint or plate. In this form of 
 weld the seam can only be welded from the side of the work 
 opposite the reinforcement, and the reinforcement, of whatever 
 
 BUTT 
 
 Fie, 80. 
 
 shape, must be welded from the side of the work to which 
 the reinforcement is applied. 
 
 FIG. 80. A Butt weld is one in which two plates or surfaces 
 are brought together edge to edge and welded along the seam 
 thus formed. The two plates when so welded form a perfectly 
 
 LAP 
 
 FIG. 81. 
 
 flat plane in themselves, excluding the possible projection 
 caused by other individual objects as frames, straps, stiffeners, 
 etc., or the building up of the weld proper. 
 
 FIG. 81. A Lap weld is one in which the edges of two 
 planes are set one above the other and the welding material so 
 applied as to bind the edge of one plate to the face of the 
 
ARC WELDING TERMS AND SYMBOLS 
 
 111 
 
 other plate. In this form of weld the seam or lap forms a 
 raised surface along its entire extent. 
 
 FIG. 82. A Fillet weld is one in which some fixture or 
 member is welded to the face of the plate, by welding along 
 
 FILLET 
 
 FIG. 82. 
 
 the vertical edge of the fixture or member (see welds shown 
 and marked A ) . The welding material is applied in the corner 
 thus formed and finished at an angle of forty-five degrees to 
 the plate. 
 
 FIG. 83. A Plug weld is one used to connect the metals by 
 
 PLUG 
 
 FIG. 83, 
 
 welding through a hole in either one plate A or both plates B. 
 Also used for filling through a bolt hole as at C, or for added 
 strength when fastening fixtures to the face of a plate by 
 drilling a countersunk hole through the fixtures and applying 
 the welding material through this hole, as at D, thereby fasten- 
 ing the fixture to the plate at this point. 
 
112 
 
 ELECTRIC WELDING 
 
 FIG. 84. A Tee weld is one where one plate is welded 
 vertically to another as in the case of the edge of a transverse 
 bulkhead A, being welded against the shellplating or deck. 
 This is a weld which in all cases requires exceptional care and 
 can only be used where it is possible to work from both sides 
 
 FIG. 84. 
 
 of the vertical plate. Also used for welding a rod in a vertical 
 position to a flat surface, as the rung of a ladder C, or a plate 
 welded vertically to a pipe stanchion B, as in the case of water 
 closet stalls. 
 
 FIG. 85. A Single "V" is applied to the "edge finish " 
 of a plate when this edge is beveled from both sides to an 
 
 SINGLE "V 
 
 FIG. 85. 
 
 angle, the degrees of which are left to the designer. To be 
 used when the "V" side of the plate is to be a maximum 
 "strength" weld, with the plate setting vertically to the face 
 of adjoining member, and only when the electrode can be 
 applied from both sides of the work. 
 
ARC WELDING TERMS AND SYMBOLS 
 
 113 
 
 F IG . 86. Double "V" is applied to the "edge finish " of 
 two adjoining plates when the adjoining edges of both plates 
 
 DOUBLE "V 
 
 SPACE 
 ANY THICKNESS '/ 8 ' 
 
 FlG. 86. 
 
 beveled from both sides to an angle, the degrees of which are 
 left to the designer. To be used when the two plates are to 
 be "butted" together along these two sides for a maximum 
 
 STRAIGHT 
 
 SYMBOL 
 
 z 
 
 : NOTES BELOW 
 
 FIG. 87. 
 
 "strength" weld. Only to be used when welding can be per- 
 formed from both sides of the plate. 
 
 FIG. 87. Straight is applied to the "edge finish" of a plate, 
 when this edge is left in its crude or sheared state. To be 
 
 SINGLE BEVEL 
 
 FIG. 88. 
 
 used only where maximum strength is not essential, or unless 
 used in connection Avith strap, stiffener or frame, or where 
 it is impossible to otherwise finish the edge. Also to be used 
 
114 
 
 ELECTRIC WELDING 
 
 for a "strength" weld, when edges of two plates set vertically 
 to each other as the edge of a box. 
 
 FIG. 88. Single Bevel is applied to the edge finish of a 
 
 DOUBLE BEVEL 
 
 FIG. 89. 
 
 plate, when this edge is beveled from one side only to an angle, 
 the degrees of which are left to the designer. To be used 
 for "strength" welding, when the electrode can be applied 
 
 DECK PLATING 
 
 FlG. 90. 
 
 from one side of the plate only, or where it is impossible to 
 finish the adjoining surface. 
 
 FIG. 89. Double Bevel is applied to the edge finish of two 
 adjoining plates, when the adjoining edges of both plates are 
 
ARC WELDING TERMS AND SYMBOLS 115 
 
 beveled from one side only to an angle, the degrees of which 
 are left to the designer. To be used where maximum strength 
 is required, and where electrode can be applied from one side 
 of the work only. 
 
 FIG. 90. Flat position is determined when the welding 
 material is applied to a surface on the same plane as the deck, 
 allowing the electrode to be held in an upright or vertical 
 position. The welding surface may be entirely on a plane 
 with the deck, or one side may be vertical to the deck and 
 welded to an adjoining member that is on a plane with the 
 deck. 
 
 Horizontal position is determined when the welding material 
 is applied to a seam or opening, the plane of which is vertical 
 to the deck and the line of weld is parallel with the deck, 
 
 TACK 
 
 FIG. 91. 
 
 allowing the electrode to be held in an inboard or outboard 
 position. 
 
 Vertical position is determined when the welding material 
 is applied to a surface or seam, whose line extends in a direc- 
 tion from one deck to the deck above, regardless of whether 
 the adjoining members are on a single plane or at an angle 
 to each other. In this position of weld, the electrode would 
 also be held in a partially horizontal position to the work. 
 
 Overhead position is determined when the welding material 
 is applied from the under side of any member whose plane 
 is parallel to the deck and necessitates the electrode being 
 held in a downright or inverted position. 
 
 FIG. 91. A Tack weld is applying the welding in small 
 sections to hold two edges together, and should always be 
 specified by giving the space from center to center to weld 
 and the length of the weld itself. No particular "design of 
 weld" is necessary of consideration. 
 
116 
 
 ELECTRIC WELDING 
 
 A Tack is also used for temporarily holding material in 
 place that is to be solidly welded, until the proper alinement 
 and position is obtained, and in this case neither the length, 
 space, nor design of weld are to be, specified. 
 
 FIG. 92. A Caulking weld is one in which the density of 
 
 CAULKING 
 
 FIG. 92. 
 
 the crystalline metal, used to close up the seam or opening, 
 is such that no possible leakage is visible under a water, oil 
 or air pressure of 25 Ibs. per square inch. The ultimate strength 
 of a caulking weld is not of material importance neither is 
 the "design of weld" of this kind necessary of consideration. 
 FIG. 93. A Strength weld is one in which the sectional 
 
 STRENGTH 
 
 FIG. 93. 
 
 area of the welding material must be so considered that its 
 tensile strength and elongation per square inch must equal 
 at least 80 per cent of the ultimate strength per square inch 
 of the surrounding material. (To be determined and specified 
 by the designer.) The welding material can be applied in 
 any number of layers beyond a minimum specified by the 
 designer. 
 
 The density of the crystalline metals is not of vital im- 
 
ARC WELDING TERMS AND SYMBOLS 
 
 117 
 
 portance. In this form of weld, the " design of weld" must 
 be specified by the designer and followed by the operator. 
 
 JP IG> 94. A Composite weld is one in which both the strength 
 and density are of the most vital importance. The strength 
 must be at least as specified for a " strength weld," and the 
 density must meet the requirements of a "caulking weld" 
 
 COMPOSITE 
 
 FIG. 94. 
 
 both as above defined. The minimum number of layers of 
 welding material must always be specified by the designer, 
 but the welder must be in a position to know if this number 
 must be increased according to the welder's working con- 
 ditions. 
 
 FIG. 95. Reinforced is a term applied to a weld when the 
 top layer of the welding material is built up above the plane 
 
 REINFORCED 
 
 FIG. 95. 
 
 of the surrounding material as at A or B, or when used for 
 a corner as at C. The top of final layer should project above 
 a plane of 45 degrees to the adjoining material. This 45 degree 
 line is shown " dotted" in C. This type is chiefly used in a 
 "strength" or "composite" kind of weld for the purpose of 
 obtaining the maximum strength efficiency, and should be speci- 
 fied by the designer, together with a minimum of layers of 
 welding material. 
 
118 
 
 ELECTRIC WELDING 
 
 FIG. 96. Flush is a term applied 'to a weld when the top 
 layer is finished perfectly flat or on the same plane as on the 
 adjoining material as shown at D and E or at an angle of 
 45 degrees when used to connect two surfaces at an angle to 
 each other as at F. This type of weld is to be used where a 
 maximum tensile strength is not all important and must be 
 
 FLUSH 
 
 FIG. 96. 
 
 specified by the designer, together with a minimum number 
 of layers of welding material. 
 
 FIG. 97. Concave is a term applied to a. weld when the 
 top layer finishes below the plane of the surrounding material 
 as at G, or beneath a plane of 45 degrees at an angular con- 
 nection as at H and J. 
 
 To be used as a weld of no further importance than filling 
 
 DOTTED LIVES SHOW THE FLUSH ! 
 
 FIG. 97. 
 
 in a seam or opening, or for strictly caulking purposes, when 
 it is found that a minimum amount of welding material will 
 suffice to sustain a specified pound square inch pressure with- 
 out leakage. In this ''type of weld" it will not be necessary 
 for the designer ordinarily to specify the number of layers 
 of material owing to the lack of structural importance. 
 
 COMBINATION SYMBOLS 
 
 FIG. 98 shows a strap holding two plates together, setting 
 vertically, with the welding material applied in not less than 
 three layers at each edge of the strap, as well as between 
 the plates with a reinforced, composite finish, so as to make 
 the welded seams absolutely water, air or oil tight, and to 
 
ARC WELDING TERMS AND SYMBOLS 
 
 119 
 
 attain the maximum tensile strength. The edges of the strap 
 and the plates are left in a natural or sheared finish. This type 
 of welding is used for particular work where maximum strains 
 are to be sustained. 
 
 FIG. 99 shows a strap holding two plates together hori- 
 
 STRAP WELD, REINFORCED, 
 COMPOSITE OF THREE LAYERS, 
 VERTICAL, STRAIGHT, 
 
 ISP*:, 
 
 PLATE 
 
 ERTICAL WELD 
 
 STRAP 
 
 w, 
 
 PLATE 
 
 FIG. 98. 
 
 zontally, welded as a strength member with a minimum of 
 three layers and a flush finish. Inasmuch as the strap neces- 
 sitates welding of the plates from one side only, both edges 
 of the plates are bevelled to an angle, the degrees of which 
 are left to the discretion of the designer. The edges of the 
 
 STRAP WELD. FLUSH, 
 I83HOF) STRENGTH OF 3 LAYERS, 
 HORIZONTAL, FLAT AND 
 OVERHEAD. DOUBLE BEVEL 
 
 Fie. 99. 
 
 strap are left in a natural or sheared state, and the maximum 
 strength is attained by the mode of applying the welding 
 material, and through the sectional area per square inch exceed- 
 ing the sectional area of the surrounding material. 
 
 FIG. 100 represents two plates butted together and welded 
 
120 
 
 ELECTRIC WELDING 
 
 flat, with a composite weld of not less than three layers, and 
 a reinforced finish. A strap is attached by means of overhead 
 tacking, the tacks being four inches long and spaced eight 
 inches from center to center. In this case, the welding of 
 the plates of maximum strength and water, air or oil tight, 
 
 STRAP, TACK, OVERHEAD. 
 8' CENTER TO CENTER 
 4' LONG, BUTT, REINFORCED 
 COMPOSITE OF 3 LAYERS, 
 FLAT. STRAIGHT. 
 
 OVERHEAD XVELD 
 
 FIG. 100. 
 
 but the tacking is either for the purpose of holding the strap 
 in place until it may be continuously welded, or because 
 strength is not essential. All the edges are left in their natural 
 or sheared state. 
 
 FIG. 101 represents a butt weld between two plates with 
 the welding material finished concaved and applied in a mini- 
 
 BUTT WELD. CONCAVE. 
 CAULKING OF 2 LAYERS. 
 FLAT. STRAIGHT 
 
 FIG. 101. 
 
 mum of two layers to take the place of caulking. The edges 
 of the plates are left in a natural shear cut finish. This symbol 
 will be quite frequently used for deck plating or any other 
 place where strength is not essential, but where the material 
 must be water, air or oil tight. 
 
 FIG. 102 is used where the edges of two plates are vertically 
 
ARC WELDING TERMS AND SYMBOLS 
 
 121 
 
 butted together and welded as a strength member. The edges 
 of adjoining plates are finished with a "double vee" and the 
 minimum of three layers of welding material applied from 
 each side, finished with a convex surface, thereby making the 
 sectional area per square inch of the weld greater than that 
 
 BUTT WELD. REINFORCED. 
 STRENGTH OF 3 LAYERS. 
 VERTICAL, DOUBLE VEE. 
 
 FIG. 102. 
 
 of the plates. This is a conventional symbol for shell plating 
 or any other members requiring a maximum tensile strength, 
 where the welding can be done from both sides of the work. 
 FIG. 103 shows two plates butted together in a flat position 
 where the welding can only be applied from the top surface. 
 It shows a weld required for plating where both strength and 
 
 93F 
 
 BUTT WELD. FLUSH, 
 COMPOSITE OF 3 LAYERS. 
 FLAT. DOUBLE BEVEL. 
 
 Fie. 103. 
 
 watertightness are to be considered. The welding material 
 is applied in a minimum of three layers and finished flush with 
 the level of the plates. Both edges of the adjoining plates 
 are beveled to an angle, the degrees of which are left to the 
 discretion and judgment of the designer, and should only be 
 used when it is impossible to weld from both sides of the work. 
 
122 
 
 ELECTRIC WELDING 
 
 FIG. 104 shows the edges of two plates lapping each other 
 with the welding material applied in not less than two layers 
 at each edge, with a concaved caulking finish, so applied, as 
 to make the welded seams absolutely water, air or oil tight. 
 
 LAP WELD. CONCAVE. 
 CAULKING OF 2 LAYERS, 
 OVERHEAD AND FLAT 
 STRAIGHT 
 
 OVERHEAD WELD 
 
 FIG. 104. 
 
 The edges of the plates themselves are left in a natural or 
 shared finish. Conditions of this kind will often occur around 
 bulkhead door frames where maximum strength is not ab- 
 solutely essential. 
 
 FIG. 105 is somewhat exaggerated as regards the bending 
 
 LAP WELD, REINFORCED. 
 STRENGTH OF 3 LAYERS 
 AND TACKING, 18' CENTER 
 TO CENTER, 6 LONG, 
 VERTICAL, STRAIGHT. 
 
 'I 
 
 FIG. 105. 
 
 of the plates, but it is only shown this way to fully illustrate 
 the tack and continuous weld. It shows the edges of the 
 plates lapped with one edge welded with a continuous weld 
 of a minimum of three layers with a reinforced finish thereby 
 giving a maximum tensile strength to the weld, and the other 
 
ARC WELDING TERMS AND SYMBOLS 
 
 123 
 
 edge of the plate, tack welded. The tacks are six inches long 
 with a space of 12 inches between the welds or 18 inches from 
 center to center of welds. In both cases, the edges of the 
 plates are left in a natural or sheared state. 
 
 PLUG AND LAP WELD, 
 STRENGTH OF 3 LAYERS 
 FLUSH. FLAT, OVERHEAD, 
 HORIZONTAL. 
 
 FLAT WELD 
 
 3 2 1 
 
 FIG. 106. 
 
 FIG. 106 shows a condition exaggerated, which is apt to 
 occur in side plating where the plates were held in position 
 with bolts for the purpose of alinement before being welded. 
 The edges are to be welded with a minimum of three layers 
 of welding material for a strength weld and finished flush, 
 
 PLUG AND FILLET WELD, 
 REINFORCED, STRENGTH OF 
 3 LAYERS, FLAT, SINGLE 
 BEVEL AND STRAIGHT. 
 
 FIG. 107. 
 
 and after the bolts are removed, the holes thus left are to be 
 filled in with welding material in a manner prescribed for 
 strength welding. The edges of the plates are to be left in 
 a natural or sheared state, which is customary in most cases 
 of lapped welding. 
 
124 
 
 ELECTRIC WELDING 
 
 PIG. 107 shows a pad eye attached to a plate by means 
 of a fillet weld along the edge of the fixture, and further 
 strengthened by plug welds in two countersunk holes drilled 
 in the fixture. The welding material is applied in a flat 
 position for a strength weld with a minimum of three layers 
 
 FILLET WELD. REINFORCED. 
 COMPOSITE OF 3 LAYERS, 
 FLAT. VERTICAL AND 
 OVERHEAD. STRAIGHT. 
 
 PIG. 108. 
 
 and a reinforced finish. The edges of the holes are beveled 
 to an angle, which is left to the judgment of the designer, 
 but the edges of the fixture are left in their natural state. 
 This method is used in fastening fixtures, clips or accessories 
 that would be subjected to an excessive strain or vibration 
 
 FILLET WELD, FLUSH, 
 STRENGTH OF 3 LAYERS 
 FLAT. STRAIGHT. 
 
 FlG. 109. 
 
 FIG. 108 shows a fixture attached to a plate by means of 
 a composite weld of not less than three layers with a reinforced 
 finish. The fixture being placed vertically, necessitates a com- 
 bination of flat, vertical and overhead welding in the course 
 of its erection. Although a fixture of this kind would never 
 
ARC WELDI'NG TERMS AND SYMBOLS 
 
 125 
 
 be required to be watertight, the composite symbol is given 
 simply as a possibility of a combination. 
 
 FIG. 109 represents a fixture attached to a plate by a 
 strength fillet weld of not less than three layers, finished flush. 
 
 TEE WELD. FLUSH. 
 STRENGTH OF 3 LAYERS. 
 FLAT. SINGLE VEE. 
 
 FIG. 110. 
 
 The edges of the fixture are left in their natural state, and 
 the welding material applied in the corner formed by the 
 vertical edge of the fixture in contact with the face of the plate. 
 FIG. 110 illustrates the edge of a plate welded to the face 
 of another plate, as in the case of the bottom of a transverse 
 
 TEE WELD. REINFORCED. 
 STRENGTH OF 3 LAYERS. 
 VERTICAL. SINGLE VEE. 
 
 FIG. 111. 
 
 bulkhead being welded against the deck plating. To obtain 
 a maximum tensile strength at the joint, the edge of the plate 
 is cut to " single vee" and welded on both sides with a strength 
 weld of not less than three layers, and finished flush. This 
 would be a convenient way of fastening the intercostals to 
 
126 
 
 ELECTRIC WELDING 
 
 the keelsons. In this particular case, the welding is done in 
 a flat position. 
 
 FIG. Ill shows another case of tec weld with the scam set- 
 ting in a vertical position, and the welding material applied 
 from both sides of the work. The edge of the plate is finished 
 with a " single vee" and a minimum of three layers of welding 
 material applied from each side, finished with a convex surface, 
 thereby making the sectional area, per square inch of the weld, 
 greater than that of the plate, allowing for a maximum tensile 
 strength in the weld. 
 
 FIG. 112 represents an example of the possible combination 
 
 STRAP AND TEE WELD, 
 FLAT, REINFORCED, TACK, 
 12' CENTER TO CENTER, 
 6' LONG, SINGLE BEVEL, 
 OVERHEAD, STRENGTH OF 
 3 LAYERS, FLUSH 
 
 FIG. 112. 
 
 of symbols. An angle iron is tack welded to the plate in the 
 form of a strap or stiffener, though in actual practice, this 
 might never occur. The tacks are spaced twelve inches from 
 center to center, and are six inches long, and applied in a 
 flat position, with a reinforced finish. As the strap prevents 
 welding the plate from both sides, the edge of the plate is 
 beveled, and the welding material applied for strength in not 
 less than three layers in an overhead position and finished 
 flush. Note that in specifying tack welds, it is essential to 
 give the space from center to center of weld, and length of 
 weld by use of figures representing inches placed either side 
 of the circumscribing symbol of the combination. 
 
CHAPTER VIII 
 EXAMPLES OF ARC-WELDING JOBS 
 
 Probably no mechanical job ever attracted more general 
 attention than the repair of the German ships seized by us 
 when we entered the World War. Even the mechanically 
 minded Germans repeatedly declared that repairing was an 
 impossibility, but the American engineers and mechanics 
 showed the Hun that he had, as usual, vastly over-rated his 
 own knowledge. One big factor in making the Hun so positive 
 in this case, was his utter ignorance regarding the possibilities 
 of arc welding but he learned and in the teaching many 
 others were also enlightened. 
 
 The work necessary on these German ships, of course, in- 
 cluded much besides welding of the broken castings, but the 
 welding work was of primary importance. 
 
 The principal ships on which this welding work was done 
 were the : 
 
 
 
 
 Grqss 
 
 Class of 
 
 U. S. Name 
 
 German name 
 
 I.H.P. 
 
 Tonnage 
 
 Vessel 
 
 Aeolus 
 
 Grosser Kurf urst 
 
 8,400 
 
 13,102 
 
 Transport 
 
 Agamemnon 
 
 Kaiser Wilhelm IT .... 
 
 45,000 
 
 19,361 
 
 Transport 
 
 America 
 
 America 
 
 15,800 
 
 22,621 
 
 Transport 
 
 Antigne 
 
 Neckar 
 
 5,500 
 
 9,835 
 
 Transport 
 
 Covington 
 
 Cincinnati 
 
 10,900 
 
 16,339 
 
 Transport 
 
 George Washington. 
 
 George Washington .... 
 
 21,000 
 
 25,570 
 
 Transport 
 
 Huron 
 
 Friedrich der Grosse. . 
 
 6,800 
 
 10,771 
 
 Transport 
 
 Leviathan 
 
 Vaterland 
 
 90,000 
 
 54,282 
 
 Transport 
 
 Maclawaska 
 
 Koenig Wilhelm II.... 
 
 7,400 
 
 9,410 
 
 Transport 
 
 Martha Washington 
 
 Martha Washington . . . 
 
 6,940 
 
 8,312 
 
 Transport 
 
 Mercury 
 
 Barbarossa 
 
 7,200 
 
 10,984 
 
 Transport 
 
 Mt. Vernon 
 
 Kronprinzessin Cecelie. 
 
 45,000 
 
 19,503 
 
 Transport 
 
 Pocahontas 
 
 Prinzess Irene 
 
 9,000 
 
 10,983 
 
 Transport 
 
 Powhatan 
 
 Hamburg 
 
 9,000 
 
 10,893 
 
 Transport 
 
 President Grant . . . 
 
 President Grant 
 
 8,500 
 
 18,072 
 
 Transport 
 
 President Lincoln. . 
 
 President Lincoln 
 
 8,500 
 
 18,168 
 
 Transport 
 
 Savannah 
 
 Saxonia 
 
 2,500 
 
 4.424 
 
 Repair Shop 
 
 Susquehanna 
 
 Ehein 
 
 9,520 
 
 10.058 
 
 Transport 
 
 Philippines 
 
 Bulgaria 
 
 4,200 
 
 10,924 
 
 Shipping Bd. 
 
 127 
 
128 ELECTRIC WELDING 
 
 The total gross tonnage of the ships named was 288,780 
 tons, and the welding work was done by the Wilson Welder 
 and Metals Co. of New York, using their "plastic-arc" process. 
 
 Seventy Cylinders Saved Without Replacement. In all, 
 there were thirty-one ships interned in the port of New York. 
 Of these thirty-one ships, twenty-seven were German and four 
 Austrian. Of the German ships, two were sailing vessels and 
 four were small steamers which the Germans had not taken 
 pains to damage materially. This left twenty-one German 
 ships whose engines and auxiliaries were damaged seriously, 
 ranging in size from the "Vaterland," the pride of the Ham- 
 burg-American Line, of 54,000 tons, to the "Nassovia," of 
 3,900 tons. 
 
 On the cylinders of the twenty vessels of German origin, 
 not counting for the moment the turbine-driven "Vaterland," 
 there were no less than 118 major breaks which would have 
 entailed the renewal of some seventy cylinders if ordinary 
 practice had been followed. In fact, such was the recommenda- 
 tion of the surveying engineers in their original report. 
 
 To any engineer familiar with the conditions at that time 
 in the machine shops and foundries in the vicinity of New 
 York, also in the drafting rooms, the problem of producing 
 seventy cylinders of the sizes required by these vessels would 
 seem almost impossible, and it is pretty well established that 
 some vessels would have had to wait nearly two years for 
 this equipment. 
 
 It must be remembered that few drawings of these engines 
 were available, and those in many cases were not discovered 
 until months after the repairs had started. Therefore, it would 
 have been necessary to make drawings from the actual 
 cylinders, and competent marine engine draftsman not already 
 flooded with work did not exist. 
 
 The cylinders of fifteen vessels were successfully welded, 
 while those of six were repaired by fitting mechanical patches, 
 or, in other words, eighty-two of the major breaks were repaired 
 by welding and thirty-six by mechanical patches. 
 
 It was not until July 12 that the final decision was made 
 placing the transport service in the hands of the Navy and 
 designating what ships were to be transferred from the control 
 of the Shipping Board to that of the Navy Department. How- 
 
EXAMPLES OF ARC-WELDING JOBS 129 
 
 ever, the first two large ships, the "Friedrich der Grosse," 
 now the " Huron," and the "Prinzess Irene," now the "Poca- 
 hontas," were ready for sea on Aug. 20, in spite of the fact 
 that the engines on these vessels were among the worst damaged 
 of them all, the " Irene" having the whole side of the first 
 intermediate valve chest broken out on each engine, the side 
 of the high-pressure cylinder on each engine destroyed, and 
 other smaller breaks, which, under ordinary methods, would 
 have necessitated the renewal of four cylinders. The "Fried- ^ 
 rich der Grosse ' ' had the following breaks : Broken valve chest Z 2: 
 of high-pressure cylinder of each engine (valve chest cast in Q 5 
 one with the cylinder), flanges knocked off both valve chest t 
 and cylinder covers, steam inlet nozzles knocked off both first ^ . 
 intermediate valve chests and walls between the two valves O 
 in each check broken out, also steam inlet nozzles on both U- Jj 
 second intermediate valve chests broken off. ^ 
 
 These two vessels were the first in which straight electric O 
 welding was used, that is, where patches were not bolted to 0) \r 
 the cylinder walls. U iu 
 
 Method of Repair. The nature of some of the breaks in 
 castings is shown by the accompanying photographs, which ? IE 
 were taken at various stages of the work. 
 
 A, Fig. 113, shows the break in the starboard high-pressure 
 cylinder of the North German Lloyd steamer " George Wash- 
 ington. ' ' This break was effected by drilling a row of holes about 
 an inch apart and knocking the piece out with a ram. 
 
 To prepare this for welding it was necessary to chisel off 
 the surface only roughly, build a pattern of the break, cast 
 a steel piece from the pattern, stud up the surface of the cast 
 iron of the cylinder with a staggered row of steel studs f in. in 
 diameter, projecting | in. from the cylinder, bevel the edge of 
 the cast piece, place the piece in position as shown in B, and 
 make the weld. When completed, the appearance of the work 
 is as it appears in C. The broad belt of welded metal is due 
 to the laying of a pad of metal over the rows of studs previously 
 noted. 
 
 It cannot be too strongly insisted that tests have shown con- 
 clusively that the weld can be properly made without this pad ; 
 that is, if the approximate strength of the original metal is all 
 that is desired in which case the studding of the metal is 
 
130 
 
 ELECTRIC WELDING 
 
 a 
 
 a 
 
EXAMPLES OF ARC-WELDING JOBS 131 
 
 unnecessary. But the work in these particular cases was of 
 vital importance, due to the uses to which the vessels were 
 to be put when in service, and also it was appreciated that this 
 exhibition of a new application of the art in the marine engineer- 
 ing world required that the demonstration be satisfying, not only 
 to the mind of the engineer, but to the eye, and ear, and when 
 any engineer looked at that band of metal and sounded it with 
 a hammer, he could not be but satisfied that the strength was 
 definitely there and that the method of padding could be used 
 in most of the situations which would arise. This at least was 
 the effect upon all the engineers who saw the actual work. 
 
 The metal was laid on in layers in such a manner as to 
 take care of the contraction in cooling. Each successive layer 
 was cleaned with a wire brush before the next layer was put 
 on. It is in the keeping of the successive layers clean and 
 in the laying on of the metal so as to take care of the con- 
 traction that the operator's ability comes in fully as much 
 as it does in the handling of the apparatus. The 'cylinders 
 were not removed, but were repaired in place. Thus the work 
 of fitting was reduced to a negligible quantity, and the refitting 
 of lagging was not interfered with by projections, other than 
 the f-in. pad, which is laid over the studs for extra strength. 
 It will also be noted that these repairs can be undertaken at 
 any place where the vessel may be lying, cither at her loading 
 dock or in the stream, since such apparatus may be carried 
 on barges, which can be placed alongside and wires run to 
 the work. 
 
 In this work a part consisted of the caulking of the surface 
 of the welds which prevents porosity and also locates any 
 brittle spots or places where poor fusion of metal has been 
 obtained. This permits the cutting out of the bad places and 
 replacing with good metal. The tool used was an air caulking 
 hammer operated at 110 Ib. air pressure. 
 
 Strength of Cast-iron Welds. Capt. E. P. Jessop, U. S. N., 
 personally tested many welds for tensile strength in which 
 cast iron was welded to cast steel, and in but one case was 
 there a failure to obtain practically the original strength. This 
 case was due to an inexperienced operator burning the metal, 
 and was easily detected as an inferior weld without the strength 
 test being applied. 
 
132 ELECTRIC WELDING 
 
 Much has been said about the effect of the heat of welding, 
 upon the structure or strength of cast iron, and in this 
 particular instance the Navy engineer who had direct charge 
 of this work, made experiments to note if there were any 
 deleterious effects on the iron resulting from the action of 
 the weld and reported as follows: 
 
 ' ' Scleroscopic investigation of the structure of the welds shows only 
 a very slight vein of hard cast iron at the line of the weld, shot through 
 with fingers of gray cast iron, while behind this area there was no heat 
 effect whatever. The metal thus deposited was easily workable with ham- 
 mer and chisel, file or cutting tool. Another very important feature is 
 that with the use of the low voltage and absolute automatic current control 
 of the Wilson system, there is a minimum of heat transmitted to the parts 
 to be welded, this being practically limited to a heat value absolutely 
 necessary to bring the electrode and the face of the metal to be welded 
 into a semi-plastic state, thus insuring a perfect physical union, and in 
 accomplishing this result neither of the metals suffers from excessive heat, 
 and there is absolutely no necessity for pre-heating. Neither are there 
 any adverse results from shrinkage following the completed work owing 
 to a minimum amount of heat being transmitted to the repair parts, thus 
 avoiding the possibility of distortion of parts through uneven or excessive 
 shrinkage strains that are very common where pre-heating is necessary or 
 excessive heat is used for fusing metals." 
 
 A, Fig. 114, shows the damage done to the first intermediate 
 cylinder of the U. S. S. ' * Pocahontas, " formerly the "Prinzess 
 Irene. " The damage to this cylinder, it will be noted, was more 
 destructive than to that of the ' ' George Washington, ' ' rendering 
 the repairs much more difficult. 
 
 B shows the steel section in place ready for welding, with 
 the surfaces properly V'd out and with a staggering row of 
 steel studs adjacent to the welding edge of the cylinder section. 
 
 C shows the complete job with the extra band or pad of 
 metal completely covering the studs on the cast-iron section. 
 These bands or pads of metal are peaned or worked over with 
 a pneumatic hammer to insure protection against porosity of 
 metal. 
 
 Had either or both of these cylinders been fractured on the 
 lines shown of the cast-iron sections, and none of the parts 
 removed, then the surfaces or edges of all lines of fracture 
 would have been V'd out, and the weld made of the two cast- 
 iron surfaces in the same manner that the cast steel was welded 
 to the cast-iron cylinder proper. 
 
EXAMPLES OF ARC-WELDING JOBS 
 
 133 
 
 I 
 
 r Jl 
 
 3d 
 
 {3 
 
 I 
 g 
 
 <o 
 
 .9 
 
 I 
 
 s 
 
134 ELECTRIC WELDING 
 
 OTHER SHIP WORK 
 
 In line with the foregoing J. 0. Smith, writing in the 
 American Machinist, Jan. 22, 1920, says: When the matter of 
 welding in connection with ship-construction is considered, im- 
 mense possibilities immediately suggest themselves. It has 
 been definitely determined by exhaustive technical study and 
 experiment that welding can be satisfactorily employed in 
 ship construction, that ship plates joined by welding will be as 
 strong or stronger than the original metal at the welded joint, 
 and that welding can be employed for ship-construction work 
 at a saving of 25 per cent, in time and 10 per cent, in material, 
 as compared to riveting. 
 
 In actual figures, as determined by experiments of the 
 Emergency Fleet Corporation's electric welding committee, it 
 was determined that, by welding, in the case of a 9500-ton 
 ship the saving in rivets and overlapped plates would amount 
 in weight to 500 tons, making it possible for the ship to carry 
 500 tons more cargo on each trip than would be possible if 
 the ship plates, etc., had been riveted, instead of welded. 
 
 An investigation by the same committee has definitely 
 established the following points: That electric-welded ships 
 can be built at least as strong as riveted ships; that plans for 
 ships designed to be riveted can easily be modified so as to 
 adapt them for extensive electric welding, and thus save con- 
 siderably in cost and time for hull construction ; that ships 
 especially designed for electric welding can be built at a saving 
 of 25 per cent, over present methods and in less time. 
 
 An electrically welded ship is credited with many ad- 
 vantages over a riveted ship. In a 5000-ton ship, about 450,000 
 rivets are used. A 9500-deadweight-ton ship requires 600,000 
 or 700,000 rivets. By the welding process the saving in labor 
 on the minor parts of a ship is reckoned at from 60 to 70 
 per cent, on the hull, plating and other vital parts ; the saving 
 in labor, cost and time of construction by welding is conserva- 
 tively placed at 25 per cent. 
 
 That electric welding will some day largely replace riveting 
 is also the judgment of the electric-welding committee which 
 is composed of many leading experts in both the electrical 
 and metallurgical branches of the welding field. 
 
EXAMPLES OF ARC-WELDING JOBS 135 
 
 Considerable investigation of the subject of welding instead 
 of riveting has been made in England by Lloyd's Register of 
 Shipping, particularly with regard to formulating rules for 
 application to the electrical welding of ships. As a result of 
 the investigations and experiments made by the technical staff, 
 it was determined that the matter had assumed such importance 
 as to warrant the formulation of provisional rules for elec- 
 trically welded vessels, and these have been issued, for the 
 guidance of shipbuilders, by Lloyd's Register. 
 
 The experiments conducted in England followed three well- 
 defined lines of investigation: Determination of ultimate 
 strength of welded joints, together with their ductile proper- 
 ties; capability of welded joints to withstand alternating ten- 
 sile and compressive stresses, such as are regularly experienced 
 by ships; and a microscopic and metallurgical analysis to 
 determine if a sound fusion was effected between the original 
 and added metal. 
 
 It was determined that the tensile strength of the welded 
 joints was from 90 to 95 per cent, of the original plates, as 
 against a strength of from 65 to 70 per cent, in riveted joints, 
 showing a margin of 25 per cent, increased strength in favor 
 of the welded joints. 
 
 The result of the tests of the elastic properties of welded 
 joints determined that there was a slight difference in favor 
 of the riveted joint, but the art of welding has made such great 
 strides recently that it is now believed entirely possible to 
 make a welded joint in ship plates that will stand as great a 
 number of reversals of stresses as a riveted joint. 
 
 Microscopic and metallurgical analyses have determined 
 that a good, solid, mechanically sound weld was made between 
 the original and the added metal, the two having been fused 
 together so perfectly that no line of demarcation could be seen. 
 
 The rules so far promulgated by Lloyd's (January, 1920), 
 have been necessarily of a tentative nature and will no doubt 
 be modified and enlarged from time to time in view of the 
 experience that will be gained after welded ships have been 
 in service for a time. 
 
 It does not require a great deal of imagination, however, 
 to enable anyone to form the opinion that the shipbuilding 
 industry is on the eve of great modifications in constructional 
 
136 ELECTRIC WELDING 
 
 lines, and the guidance given by the tests and comparisons 
 so far made will undoubtedly lead to important, radical de- 
 partures and developments. 
 
 In addition to the increased cost of riveting as compared 
 to welding, it is practically always true that there is a certain 
 percentage of imperfectly fitted rivets, that do nothing more 
 than add weight to the ship. The main purpose of a rivet, 
 of course, is to bind two or more thicknesses of material to- 
 gether, but? if the rivet is bent, loses part of its head in the 
 riveting process or otherwise fails in its proper purpose, there 
 is no method by which such faults can be corrected after the 
 rivet cools. If the importance of the riveted part requires 
 a perfect joint, the faulty rivets must be removed entirely, 
 and this is frequently a time-killing, expensive course to fol- 
 low. When it is considered that a 5500-ton ship requires 
 approximately 450,000 rivets to bind the various parts and 
 plates and also that a certain percentage of these rivets is 
 not fulfilling the purpose for which they were put into the 
 ship, it is quite evident that practically every ship is burdened 
 with a good-sized load of dead, useless weight. Such defective 
 rivets are, in fact, more than a useless weight, in that they 
 are a menace to the ship, for while they have been built into 
 the ship for a purpose, and are supposed to be fulfilling that 
 purpose, there is no telling how much the ship has been weak- 
 ened structurally by their failure. 
 
 There are many reasons for defective t rivets, and one of 
 the greatest of them is the inaccessibility of the parts to be 
 riveted and the consequent difficulty on the part of the riveter 
 in putting the rivets properly in place. Another reason is that 
 there is no certainty that rivets are at a proper, workable 
 temperature; in consequence of which if they are too cold, 
 the pneumatic hammer now generally used in riveting is unable 
 to round off the end of the rivet properly, so as to insure a 
 proper binding together of the plates the rivet is supposed 
 to hold. 
 
 In many cases, when such faulty rivets are discovered, the 
 present-day method is to weld such defective spots, which 
 immediately brings up the natural question as to why the 
 plates should not be welded in the first place. 
 
 The ability of a welder, using a direct-current, low-voltage 
 
EXAMPLES OF ARC-WELDING JOBS 
 
 137 
 
 arc with automatically regulated current to make sound 
 mechanical welds in cramped, confined spaces, on overhead 
 
 FIG. 115. Welded Parts for Ships. 
 
 or vertical walls, in fact, anywhere a man and a wire can go, 
 naturally suggests that welding ship plates together should be 
 the primary operation in shipbuilding; and from present in- 
 
 FIG. 116. Welded Fuel-Oil Tanks. 
 
 dicatlons and the trend of current events, it seems more than 
 likely that this will be the outcome in the near future. 
 
 Examples of various ship parts welded by the metallic arc 
 
138 ELECTRIC WELDING 
 
 are shown in Fig. 115. In Fig. 116 is shown a welded tank 
 and in Fig. 117 a welded steel-plate, 4X7 ft. condenser. 
 
 Reason for Successful Welds. In connection with the 
 work just described, the Wilson people claim that their success, 
 and the uniformity of their welds, was made possible because 
 their apparatus enables the welder to control his heat at the 
 point of application. In welding there is a critical temperature 
 at which steel can be worked to give the greatest tensile 
 strength, and also ductility of metal. By raising the heat 
 15 or 20 amp. above this critical amperage a fracture of the 
 
 FIG. 117. Welded Steel-Plate Condenser. No Rivets in Its Construction. 
 
 Size 4 x " Ft. 
 
 weld will show segregation of carbon and slag pockets, which, 
 of course, weakens the weld. If the amperage is decreased 
 from the critical temperature, a fracture of the weld will show 
 that the metal has been deposited in globules, with many voids, 
 which proves that the weld has been made with insufficient 
 heat. This shows, they claim, that with a fluctuating amperage 
 or voltage, it is impossible to obtain uniformly high-grade 
 welds. 
 
 In addition to their apparatus they use special electrodes 
 for various jobs. One electrode is composed of a homogeneous 
 alloy combined with such excess of manganese as will com- 
 pensate for losses while passing through the electric arc, thus 
 
EXAMPLES OF ARC-WELDING JOBS 
 
 139 
 
 insuring a substantial amount of manganese in the welded joint 
 which is essential to its toughness. They also claim to have 
 
 Fie. 118. Welded Locomotive Frame. 
 
 FIG. 119 Built Up Pedestal Jaw. 
 
 a manganese copper alloy welding metal electrode which is 
 composed of iron homogeneously combined with such an ex- 
 cess of manganese and copper over the amount lost in the 
 
140 
 
 ELECTRIC WELDING 
 
 arc as will insure to the welded joint a substantial additional 
 degree of toughness and ductility. 
 
 Their special electrodes run in grades, corresponding in 
 sizes to the gage numbers of the American Steel and Wire 
 Co.'s table. Grade 6 is for boiler work; grade 8 can be 
 machined ; grade 9 is for engine frames, etc. ; grade 17 is for 
 filling castings and grade 20 is for bronze alloys, bells, etc. 
 The tensile strength of welds made with these electrodes is 
 
 FIG. 120. At Work on a Locomotive Frame. 
 
 given as from 40,000 to 60,000 Ib. The wire furnished is usually 
 gage 9, approximately 5 / 32 in. in diameter. This is shipped 
 in coils of about 160 Ib. No fluxes are used with any of these 
 electrodes. 
 
 Locomotive Work. The railroad shops of the United States 
 were among the first to use arc welding to any extent. In 
 fact, without the great amount of experimental work done in 
 railroad shops, the use of the arc in the repair of the damaged 
 ships by welding would have been practically impossible. 
 
EXAMPLES OF ARC-WELDING JOBS 
 
 141 
 
 In some cases of locomotive repair there is a big question 
 in the minds of engineers as to whether replacement is to be 
 insisted upon or welding allowed. Rules have been drafted 
 by a number of railroad associations, but at present no uniform 
 rules covering all cases are in existence. However, on certain 
 
 FIG. 121. Welding Cracked Driving Wheel Spokes. 
 
 classes of work there is no real question that welding is the 
 quicker and better way. 
 
 In Fig. 118 is shown a repair on a steel locomotive frame, 
 the size of the smaller section being 5X6 in. The broken ends 
 were beveled off on each side and a piece of steel bar was 
 welded in between the ends, thus saving considerable time and 
 electrode material. 
 
142 
 
 ELECTRIC WELDING 
 
 Fig. 119 shows how the worn face of a pedestal jaw was 
 built up by means of the " plastic-arc" process. 
 
 FIG. 122. Welding Locomotive Boiler Tubes to Back Sheet 
 
 FlG. 123 .Method of Welding Boiler Tubes to Sheet. 
 
 Another frame-welding job is shown in Fig. 120. The weld 
 was 3 in. high, 4| in. wide and 4 in. deep. One man finished 
 the job with a Westinghouse outfit in about 5 hours. 
 
EXAMPLES OF ARC-WELDING JOBS 143 
 
 Fig. 121 shows the welding of a locomotive cast-steel drive 
 wheel. Four spokes were cracked. 
 
 Fig. 122 shows the welding of locomotive boiler tubes to 
 the back flue sheet. All of these jobs were done by the "plastic- 
 arc" process, and represent a very small portion of the kinds 
 of jobs that may be done in a railroad shop. 
 
 The method of welding flue ends to the sheets as suggested 
 by Westinghouse is shown in Fig. 123. 
 
 II. A. Currie, assistant electrical engineer, New York Cen- 
 tral R.R., writing in Railway Age, says: 
 
 The saving in our locomotive shop since electric welding was installed 
 can hardly be calculated and the additional mileage that is obtained from 
 locomotives is remarkable. This is mainly due to the following: 
 
 "A. Greater permanency of repairs. 
 
 "B. Shorter periods in the shop, giving additional use of equipment. 
 
 "C. Existing shop facilities permit taking care of a larger number of 
 locomotives than originally expected. Shop congestion relieved. 
 
 "D. The use of worn and broken parts which without electric welding 
 would be thrown in the scrap pile. 
 
 ' ' E. The time required to make repairs is much less and requires 
 fewer men. 
 
 " F. A smaller quantity of spare parts carried in stock. 
 
 "The following is a brief description of some of the work done on 
 steam locomotives: 
 
 "Flue and Fire Box Welding. The most important results are obtained 
 by welding the boiler tubes to the back flue sheet. The average mileage 
 between shopping on account of leaky flues on passenger locomotives was 
 100,000 miles. This has been raised to 200,000 miles with individual 
 records of 275,000 miles. For freight this average has been raised from 
 45,000 to 100,000 miles. At the time of locomotive shortage this effect 
 was of inestimable value. 
 
 "Good results have been obtained without the use of sandblast to 
 prepare the tubes and sheets. The engine is either fired or an acetylene 
 torch used to burn off the oil, after which the metal is cleaned off with a 
 scraping tool. The ferrules are of course well seated and the tubes rolled 
 back. The boiler is filled wilh water in order to cool the tubes, which 
 having a much thinner cross-section than the sheets, would overheat suffi- 
 ciently to spoil the weld or burn the tube. The metal is then laid on, 
 beginning at the bottom of the bead and working to the top. Records 
 show that the time to weld a Pacific type locomotive boiler complete is 
 12 hours. 
 
 ' ' A variety of repair work is readily accomplished in locomotive fire- 
 boxes such as the welding of crown-sheet patches, side-sheet cracks and the 
 reinforcing and patching of mud rings. Smokebox studs are also welded on. 
 
 "Side Frames, Couplers and Wheels. Cracked main members of side 
 
144 ELECTRIC WELDING 
 
 frames are restored and wearing parts built up and reinforced. Because 
 of accessibility no special difficulties are encountered in this work. Formerly 
 this work was chiefly done with oil welding and some acetylene and thermit 
 work, but it was very much more expensive as the preparation required 
 considerable effort and took a good deal of time. 
 
 "Fifty per cent of the engines passing through the shops have worn 
 and broken coupler parts and pockets. By welding an average saving of 
 about $15 per coupler is made. It costs about $30 in material and labor 
 to replace a coupler and only $4 to repair the average broken coupler. 
 The scrap value is about $5. 
 
 ''Great success has resulted from various repairs to steel wheels and 
 tires. Flat spots have been built up without removing the wheels from 
 the locomotives, thus effecting a great saving in time and money. Building 
 up sharp flanges saves about f-in. cut off the tread, which when followed 
 through means about $30 for a pair of wheels, a great increase in tire 
 life and reduction in shop costs. 
 
 "Cylinders. The most interesting feature developed by arc welding 
 was the accomplishment of cast-iron welding. The difficulty in welding 
 cast iron was that while the hot metal would weld into the casting, on 
 cooling the strain would tear the welded portion away from the rest 
 of the casting. Small studding was tried out with no success. Not until 
 wrought-iron studs, proportioned to the sectional strength of the casting, 
 were used did any satisfactory welds turn out. Studding of this large 
 size was looked upon with distrust, as it was thought that the only weld 
 was to the studding. This naturally meant that the original structure 
 was considerably weakened due to the drilling. This, however, was not 
 the case. The large studding was rigid enough to hold against the cooling 
 strains and prevented the welds in the casting from pulling loose, thus 
 adding the strength of all the welded portion to that of the studs. In 
 most cases where external clearance will permit, sufficient reinforcing can 
 be added to more than compensate for the metal removed in drilling for 
 the studs. 
 
 "Perhaps more skill is required for this class of welding, but with a 
 properly prepared casting success is certain. A concrete case of the economy 
 effected in welding a badly damaged cylinder on a Pacific type engine 
 is as follows: 
 
 WELDED JOB 
 
 Cost of welding broken cylinder, labor and material $125.00 
 
 Length of time out of service, 5 days at $20 a day 100.00 
 
 Scrap value of old cylinder (8,440 Ib. at 2.09 Ib.) 177.00 
 
 Total $402~00 
 
 EEPLACED CYLINDER 
 
 Cost of new cylinder ready for locomotive $1,000.00 
 
 Labor charge to replace it 150.00 
 
 Locomotive out of service 18 days at $20 a day 360.00 
 
 $1,510.00 
 
 Less cost of welding 402.00 
 
 Total saving ~$ 1,108. 00 
 
EXAMPLES OF ARC-WELDING JOBS 145 
 
 "Some twenty-five locomotives have been repaired in this way at one 
 shop alone. 
 
 "Many axles are being reclaimed by building up the worn parts. 
 These are tender and truck axles which are worn on the journals, wheel 
 fits and collars. The saving is about $25 per tender axle and $20 for 
 truck axles. 
 
 ' ' The range of parts that may be repaired or brought back to standard 
 size by welding is continually expanding. Wearing surfaces on all motion 
 links and other motion work, crosshead guides, piston-rod crosshead fits, 
 valves and valve seats, air, steam, sand and other pipes, keys, pins and 
 journal boxes have all been successfully welded. 
 
 "A large saving is effected in welding broken parts of shop tools and 
 machinery. During the war this was of untold value, as in some cases 
 it was out of the question to get the broken parts replaced. 
 
 "Training of Operators. The training of arc welders is most important. 
 Success depends solely on the men doing the work. They must be instructed 
 in the use of the arc, the type, size and composition of the electrode 
 for various classes of work and the characteristics of the various machines 
 they will be called upon to use. ,A properly equipped school for teaching 
 these matters would be a valuable adjunct for every railroad. Manufac- 
 turers of equipment have recognized the importance of proper instruction 
 and have equipped schools where men are taught free of charge. 
 
 "Supervision. Co-ordinate with the actual welding is intelligent super- 
 vision. The scope of the supervisors should include preparation of the 
 job for the welder and general oversight of the equipment in the shop. 
 
 ' ' Thus the duties of the inspector might be summarized in the following 
 points : 
 
 "1. To see that the work is properly prepared for the operator. 
 "2. The machines and wiring are kept in good condition. 
 "3. Proper electrodes are used. 
 
 "4. To inspect the welds in process of application, and when finished. 
 "5. To act as adviser and medium of interchange of welding practices 
 from one shop to another. 
 
 "In work such as flue welding and industrial processes which repeat 
 the same operation, piece-work rates may be fixed. For varying repair 
 jobs this method cannot be used with justice either to the operator or 
 the job. 
 
 "Bare electrodes are used almost exclusively, even for a.c. welds. 
 Whenever a new lot of electrodes is received it is good practice to make 
 up test-piece samples and subject them to careful tests and analysis. 
 
 ' ' The sizes of electrodes and uses to which they are put are shown 
 in the table. 
 
 Size Type of Work 
 
 Y S in. Flue welding. 
 
 6 /32 i n - For all repair work, broken frames, cylinders, etc. 
 
 Y in - For building up wearing surfaces. 
 
146 
 
 ELECTRIC WELDING 
 
 "General Rules. In closing it will be well to point out a few general 
 rules required to obtain satisfactory welds. 
 
 "1. The work must be arranged or chipped so that the electrode may 
 be held approximately perpendicular to the plane of welding. 
 When this cannot be accomplished the electrode must be bent 
 so that the arc will be drawn from the point and not the side 
 of the electrode. For cast iron the studding must be properly 
 arranged and proportioned. The surfaces to be welded must be 
 thoroughly clean and free from grease and grit. 
 
 "2. The proper electrode and current value must be selected for the 
 work to be done. 
 
 "3. The arc should be maintained as constant as possible. 
 
 "4. For nearly all work the prepared surface should be evenly welded 
 over and then the new surfaces welded together. 
 
 "5. Suitable shields or helmets must be used with proper color values 
 for the lenses. 
 
 FIG. 124. Built Up Cupped Rail Ends. 
 
 1 ' For locomotive work a good operator will deposit an average of 
 1 to 1 Ib. of electrode per hour. The limits are from 1 to 2 Ib. High 
 current values give more ductile welds, in proportion to deposited metal. 
 For locomotive welding the great advantage of the arc over thermit, oil 
 or acetylene welding is that preparation at the weld is all that is necessary. 
 No secondary preparation for expansion of the members is necessary. This 
 is the great advantage in welding side frames." 
 
 Considerable welding work is done in building up worn 
 track parts. Fig. 124 shows the building up of cupped rail 
 ends and Fig. 125 shows manganese-steel cross-over points 
 built up by arc welding. Such repairs have stood long and 
 hard service. 
 
EXAMPLES OF ARC-WELDING JOBS 
 
 147 
 
 Other Welding Work. In the steel mills a great deal of 
 welding is required to build up worn roll or pinion pods. Fig. 
 126 shows a welder at work building up worn pods with a 
 carbon arc and filler. Fig. 127 shows a finished job with the 
 
 FIG. 125. Built Up Manganese Steel Cross-Over Points. 
 
 FIG. 126. Building Up Worn Roll Pods. 
 
 worn part outlined in white. The cost of repairing four ends 
 (two pinions) was $170. The pinions cost $1,000 each. 
 
 The way a five-ton roll housing Avas repaired is shown in 
 Fig. 128. In this case a heavy steel plate was bolted over 
 the crack and welded as indicated. It might have been all 
 
148 
 
 ELECTRIC WELDING 
 
 FIG. 127. Finish-Welded Pinion Pods. 
 
 FIG. 128. Kepaued 5-Ton Koll Housing. 
 
EXAMPLES OF ARC-WELDING JOBS 
 
 149 
 
 FIG. 129. Welded Blowholes and Machined Pulley. 
 
 FiG. 130, Method of Welding Taps Broken Off in the Hole. 
 
150 ELECTRIC WELDING 
 
 right to weld direct, but in this case, owing to the heavy duty 
 required, it was thought best to play safe and use the steel 
 plate. 
 
 Welded blowholes in the rim of a large pulley are shown 
 at the left in Fig. 129. At the right the pulley is shown after 
 machining. 
 
 Broken taps may be removed if a nut is welded on as 
 shown in Fig. 130. In doing work of this kind, the arc is 
 struck on top of the tap and kept there until the metal is 
 built up above the top of the hole. An ordinary nut is then 
 laid over it and welded fast. If the arc is kept on the tap 
 the metal may run against the sides of the hole but will not 
 adhere, but care must be exercised so as to not let the arc 
 strike the sides of the hole. 
 
 ELECTRIC CAR EQUIPMENT MAINTENANCE 
 
 The growing possibilities of electric welding processes in 
 connection with the maintenance of rolling ctock and other 
 railway equipment have been a source of amazement to every 
 electric railway man who has come into contact with the prac- 
 tice, says the Electric Railway Journal. This began with the 
 repair of broken members of the various parts of electric car 
 equipment and has led to its use in a still larger field, which 
 includes the building up of worn surfaces of steel parts which 
 previously would have been headed for the scrap heap. The 
 accompanying illustrations show some parts of electric car 
 equipment which have been reclaimed by electric welding in 
 the shops of several electric railways. This work was begun 
 at a time when it was very difficult to obtain railway equip- 
 ment parts and it has resulted in large savings and has enabled 
 the equipment to be returned to service so quickly, that the 
 work is being extended and used for defective-part repair 
 which previously would not have been considered. 
 
 The United Traction Company, Albany, N. Y., constructed 
 a special concrete building for its electrical repair work a year 
 ago. A separate room was built at one end of this building and 
 arranged particularly for electric welding, and all important 
 details were incorporated in the design to fit this room for the 
 purpose to which it was to be put. The building is a concrete 
 structure throughout and the floor of the welding room is also 
 
EXAMPLES OF ARC-WELDING JOBS 
 
 151 
 
 of concrete. In dimensions this room is about 10 ft.X30 ft. and 
 it is entirely inclosed and separated from the rest of the 
 building. 
 
 As a safety precaution no one is allowed to enter the weld- 
 ing room while work is in progress. Two observation windows 
 are provided on either side of the entrance door, in which 
 colored glass has been installed as a protection to the eyes of 
 the observer. Any one having business in the welding room 
 
 PIG. 131. G. E. Portable Arc Welding Outfit. 
 
 can see when welding work is being done and thus avoid the 
 danger of any harmful effect from the light of the arc. 
 
 The equipment at present in use in the welding room con- 
 sists of a General Electric motor-generator set and an oxy-acety- 
 lene welding outfit, a welding table, convenient holders, masks 
 and other welding equipment, and a chain hoist which travels 
 on an I-beam the length of the room and also outside the 
 entrance to pick up heavy work and facilitate the handling of 
 heavy parts. Since the installation of this equipment the 
 General Electric Company has developed a self regulating 
 welding generator which constitutes a part of its single-operator 
 
152 
 
 ELECTRIC WELDING 
 
 metallic electric arc welding equipment. This can be either 
 stationary or portable and as it is self-contained it makes a 
 very desirable combination. The generator has a two-pole 
 armature, in a four-pole frame, with commutating poles, and 
 generates sixty volts, open circuit. Bucking the shunt field 
 is a series field, with taps brought out for different welding 
 currents. As current flows from the main brushes through 
 the series field windings it reduces the generator voltage to 
 
 FIG. 132. G. E. Generator Direct Connected to Motor, with Control 
 Panel and Starter. 
 
 the proper welding value. Figs. 131 and 132 show two types 
 of G. E. equipment. 
 
 One of the most important operations and one which shows 
 far reaching economies in the work undertaken by the United 
 Traction Company is the building up of worn armature shafts, 
 as shown in Figs. 133 and 134. The pinion ends of the shafts 
 were "chewed up" due to the wear of the keyways for the 
 pinions. The defective ends of the shafts which were to be 
 repaired were carefully cleaned of all oil and dirt and sufficient 
 metal was welded on so that the shafts could be re-machined 
 
EXAMPLES OF ARC-WELDING JOBS 
 
 153 
 
 and re-threaded. A large number of these armatures were all 
 right except for the damage to the keyways, so that they 
 were returned to service as soon as the shafts were re-machined 
 
 FlG. 133. Worn Armature Shafts Before Welding. 
 
 FIG. 134. Armature Shafts After Welding. 
 
 and fitted. Others had damaged coils or grounded insulation 
 and where it was necessary to re-wind an armature this was 
 stripped before the welding operations took place. For weld- 
 
154 
 
 ELECTRIC WELDING 
 
 ing operations of this character where a large amount of work 
 is to be done which is similar in character the General Electric 
 Company has developed an automatic welding machine 
 described elsewhere. Its chief advantage lies in the increase 
 
 in speed which is possible and the uniformity of welds which 
 results. In the work done at Albany the building up and 
 re-machining of the shafts cost from $3 to $4 each, which was 
 only about one-tenth of the cost of a new shaft. As local 
 
EXAMPLES OF ARC-WELDING JOBS 155 
 
 conditions as to labor costs as well as the cost of energy vary 
 to quite an extent detailed costs for the various operations 
 are not included, but on roads which are performing this work 
 and which have actual data regarding the purchase cost of 
 the various parts, the savings which result offer convincing 
 proof of the economies which can be effected with the use of 
 electric arc welding. 
 
 Fig. 135 shows a pile of motor cases in the yards of the 
 United Traction Company. Before the advent of the welding 
 equipment many of these motor shells were intended for scrap 
 
 FIG. 136. Kepaired Gear-Case Suspension Arm. 
 
 due to various breakages and excessively worn parts. By the 
 use of the welding equipment a large proportion of these have 
 already been reclaimed. 
 
 The method employed in welding broken lugs or broken 
 ends of motor shells consists first in fitting the broken parts 
 together and lining them up in their correct position. The 
 pieces are then welded at a few points so as to hold the broken 
 parts in position and, where necessary, the fracture is cut out 
 "V" shape to provide additional space for the welding metal. 
 Much of the success which has been obtained in this class of 
 work at Albany is attributed to the use of studs for inter- 
 
156 
 
 ELECTRIC WELDING 
 
 locking the metal which is added to the broken parts. Holes 
 for the f-in. studs are drilled and tapped at several points 
 adjacent to the break and the studs are so inserted as to 
 extend above the motor shell to about the same height as the 
 thickness of the additional metal to be added. The deposited 
 
 FIG. 137. Broken Cast-Iron Motor Slrell and Axle Housings Repaired by 
 Electric Welding (Case Broken in Twelve Pieces). 
 
 metal is then allowed to bridge over these studs in welding 
 and so obtains additional support which helps to strengthen 
 the weld. In the illustration Fig. 136 showing repairs made 
 to a broken gear-case suspension arm, one of these studs can 
 be seen projecting from the casting. 
 
EXAMPLES OF ARC-WELDING JOBS 
 
 157 
 
 As an example of what can be accomplished, in repairing 
 broken shells, the illustration Fig. 137 showing a welded end 
 of a motor shell alongside a lathe, is an extreme case. This 
 motor shell was broken in twelve pieces and from the illus- 
 tration it will be seen that nearly the entire end was welded. 
 
 Another record job made in the shop of the United Traction 
 Company was the welding of a truck bolster. The car, under 
 which was a truck with a broken bolster, was brought to the 
 shop and placed on a track adjacent to the welding room. 
 
 FIG. 138. FIG. 139. 
 
 FIG. 138. Wheel Turned Down Ready for Welding. Note 
 
 Thinness of Flange. 
 FIG. 139. Flange Built Up Ready to Be Shaped in Wheel Lathe. 
 
 The car body was jacked up and the bolster was repaired 
 in approximately eight hours. The work was started at 9 
 o'clock after the morning rush hour and the car was ready 
 for service again at 5.15 P.M. 
 
 In addition to the class of work illustrated as being done 
 by the United Traction Company other interesting work is 
 reported from various electric railways showing what has been 
 accomplished. The Spokane & Inland Empire Railroad has 
 done some work in reclaiming wheels with sharp flanges. 
 Three views are given to illustrate the methods used. The 
 
158 
 
 ELECTRIC WELDING 
 
 first of these, Fig. 138, shows a wheel with the flange turned 
 down ready to receive new metal. The second Fig. 139 shows 
 the flange with a new layer of welded metal. The third, Fig. 
 140, shows the finished wheel after it has been machined. After 
 the new metal has been added the flange is merely shaped up 
 with a forming tool. It is left quite rough in some cases, but 
 as the practice has always been to put on new brake shoes 
 when the wheels are repaired, the company has had no difficulty 
 in wearing down the tread to a smooth contour. 
 
 A number of steam railways are at present reclaiming all 
 of their cold rolled steel wheels which are slid flat or have 
 
 
 FIG. 140. Finished Wheel Ready for Service. 
 
 flaked-out places, as well as those with sharp flanges. This 
 operation creates quite a saving in itself as often the car is 
 merely placed over the drop pit and the work can then be 
 taken care of with the car fully equipped. By this method 
 the car is withheld from service but a short period. In the 
 welding of sharp flanges it is not contended by those who have 
 had extended experience that the metal deposited will give 
 the life of the parent material, but they agree that savings 
 are created as a result of maintaining the car in service until 
 such time as it is necessary to shop it for major repairs. 
 
 Another example of reclaiming electric car equipment is 
 shown in the repairs to gear cases, Fig. 141. These are a 
 
EXAMPLES OF ARC-WELDING JOBS 
 
 159 
 
 fair sample of the repairs that are frequently found necessary. 
 In this case patches are made of No. 10 sheet iron. In welding 
 these patches on, the operator first determines the size of the 
 patch and outlines it with chalk on the old case. He then 
 builds up a layer of metal just outside the chalk mark. The 
 patch is then laid on and welded to a layer of metal. In 
 this way a tight and secure joint is made. As gear cases are 
 frequently covered with oil when they are brought in for 
 repairs, they should be cleaned off as much as possible. In 
 making a patch that requires a bend, as in the case illustrated, 
 the operator first welds the patch to the bottom of the case, 
 then heats the patch and bends it into shape. 
 
 Split Gears Made Solid. Some electric railways which have 
 
 FlG. 141. Gear Cases with Patches Welded On. 
 
 split gears have found it advisable to change these to solid 
 gears by welding and then to press them on the axles. Fig. 
 142 shows a gear which is being welded in this manner and 
 Pig. 143 an axle which has been built up so as to increase 
 the gear seat. The method employed in welding the gears 
 consists, first, of cutting a "V" along the joint of the gear 
 down to the bolts with a carbon electrode. The operator then 
 builds up with new metal and welds each bolt and fills up 
 the old keyways. This bore is then re-machined and a new 
 keyway is cut. Broken teeth in gears are also easily repaired 
 by welding. 
 
 Another use of welding which has been of benefit to electric 
 railways is in the maintenance of housings for the bearings 
 of railway motors. Constant vibration and heavy jarring 
 
160 
 
 ELECTRIC WELDING 
 
 causes the fit in the motor frame to become badly worn and 
 many railways have used shims to take up this wear. A small 
 layer of metal deposited by the electric arc and then machined 
 to the desired dimensions provides a more serviceable job than 
 
 FIG. 142. 
 
 FIG. 143. 
 
 FIG. 142. Welding Split Gear to Make a Solid One. 
 FIG. 143. Axle Enlarged by Welding. 
 
 that of the shims, and when a tight fit is once secured, the 
 wear is eliminated. 
 
 The filling in of bolt holes in various parts of the car 
 equipment is another use which is showing far-reaching results. 
 Heavy duty and constant vibration cause the holes to become 
 worn, and the bolts then readily become loose and often fall 
 
EXAMPLES OF ARC-WELDING JOBS 
 
 161 
 
 out. The filling in of these holes and their re-drilling takes 
 very little time and the cost is extremely low. 
 
 Some other welding operations which have been carried 
 out with success are these: side bearings which have become 
 
 FIG. 144. Crankshaft with Break Cut away for Welding. 
 
 FIG. 145. Completed Weld Before Trimming. 
 
 badly worn have been built up, brakeshoe heads and hangers 
 have been welded and truck side frames have been repaired 
 in numerous cases. A large number of uses for electric welding 
 are constantly presenting themselves to all railways. Enough 
 instances have been cited to demonstrate the fact that the art 
 
162 ELECTRIC WELDING 
 
 of welding has greatly increased the resources available for 
 lengthening the life of equipment. 
 
 ELECTRIC WELDING A SIX-TON CRANKSHAFT 
 
 A. six-ton crankshaft in the plant of the Houston Ice Co., 
 Houston, Tex., broke through at one of the webs. As there 
 was no means at hand to repair the break, the crankshaft 
 was shipped to the Vulcan Iron Works, Jersey City, N. J., 
 where it was electrically welded by the Wilson plastic-arc 
 process. 
 
 The broken web, cut away preparatory to welding, is shown 
 in Fig. 144, and the finished weld in Fig. 145. Owing to the 
 size of the shaft, great care had to be exercised in keeping 
 it in proper alignment. Fig. 146 shows it leveled and clamped 
 to a large surface plate. A straight-edge is shown laid across 
 the webs to assist the operator in judging and keeping the 
 alignment. 
 
 A big feature in electric welding of this kind is 'that owing 
 to the intense heat of the arc, no preheating is required as in 
 using other methods. This, of course, greatly reduces the time 
 required to complete a repair of this kind. 
 
 ARC-WELDING HIGH-SPEED TOOL TIPS 
 
 One large manufacturer has installed a Westinghouse arc- 
 welding equipment for the sole purpose of making tools for 
 turning heavy work. Ordinarily these tools are made from 
 high-speed steel, and cost about $12 each. This manufacturer 
 uses high-speed steel for the tip of the tool only, welding 
 it to a shank of carbon or machine-steel, as shown in Fig. 147, 
 and in this manner the tools are produced at a cost of $2 
 to $4. 
 
 For several weeks this plant has been turning out 240 
 welded tools a day, the men working in shifts of four, which 
 is the capacity of this outfit. 
 
 The equipment consists of a 500-amp. arc-welding motor 
 generator with standard control panel, and three outlet panels 
 for metal-electrode welding, and one special outlet panel for 
 the use of either metal or graphite electrodes. The special 
 panel is intended to take care of special filling or cutting 
 
EXAMPLES OF ARC-WELDING JOBS 
 
 163 
 
164 ELECTRIC WELDING 
 
 processes that may be necessary, but ordinarily it is used in 
 the same manner as other panels for making tools. These 
 panels are distributed about the shops at advantageous points. 
 For toolmaking, which involves the hardest grades of steel, 
 a preheating oven is used, not because it is necessary for mak- 
 ing a perfect weld, but because otherwise the hard steel is 
 likely to crack from unequal cooling and also because pre- 
 
 FIG. 147. Welding High-Speed Tips Onto Mild Steel Shanks. 
 
 heating makes it easier to finish the tool after the welding 
 process has been completed. For ordinary arc welding opera- 
 tions the preheating oven is never used. 
 
 ELECTRICALLY WELDED MILL BUILDING. 
 
 A small all-welded mill building was erected in Brooklyn 
 in 1920 for the Electric Welding Co., of America, by T. 
 Leonard MacBean, engineer and contractor. The structure is 
 about 60 X 40 ft., and has four roof trusses of 40-ft. span 
 supported on 88-in. H-beam columns fitted with brackets for a 
 five-ton traveling crane. In its general arrangement the struc- 
 ture follows regular practice, but the detailing is such as to 
 suit the use of welding, and all connections throughout are 
 made by this process. A considerable advantage in cost and 
 time is claimed for the welded connections, but in the present 
 
EXAMPLES OF ARC-WELDING JOBS 165 
 
 instance the determinative feature was not cost economy so 
 much as the fact that the fabricated work could be obtained 
 more quickly by buying the plain steel members and cutting 
 and welding them at the site instead of waiting for bridge shop 
 deliveries. 
 
 The roof was designed for a total load of 45 Ib. per sq. ft., 
 of which about 30 Ib. represents live load. Each truss weighs 
 1,400 Ib. The chords are 4X5Xf-in. tees, while the web mem- 
 bers are single 3X2Xf-in. angles. On the trusses rest 10-in. 
 15-lb. channel purlins spanning the 20-ft. width of bay. The 
 columns are 8x8-in. H-beams, 19 ft. high, and the crane bracket D 
 on the inner face of the column is built up of a pair of rear Q 
 connection angles, a pair of girder seat angles, and a triangular 
 web plate, as one of the views herewith shows. Base and cap 
 of the columns are made by simple plates. 
 
 All material was received on the job cut to length. A 
 wooden platform large enough to take a whole truss was 
 built as a working floor and the chord members were laid 
 down on it in proper relative position to form a -truss when 
 connected. The top chord was made of a single length of tee, 
 bent at the peak point after a triangular piece was cut out 
 of the stem. At the heel points of the truss the stem of the 
 top-chord tee was lapped past the stem of the bottom chord 
 tee, and when the two members were clamped together the 
 contact seams were welded; the seam of the stem at the peak 
 was also welded shut. Then the web members were placed 
 in position and clamped, and their connections to the chord 
 welded. The metallic-electrode arc process was used and 
 various welded parts are shown in Fig. 148. 
 
 Loading Tests. When the plans for the building were sub- 
 mitted to the Department of Buildings, Borough of Brooklyn, 
 the proposal to weld the connections was approved only with 
 the stipulation of a successful load test before erection. This 
 test was carried out March 20. Two trusses were set up at 
 20-ft. spacing and braced together, purlins were bolted in 
 place, and by means of bags of gravel a load of 48 tons was 
 applied. This was sufficient to load the trusses approximately 
 to their elastic limit. No straining or other change was observ- 
 able at the joints, and the test was considered in every respect 
 successful. The deflection of the peak, 0.0425 ft., did not 
 
166 
 
 ELECTRIC WELDING 
 
EXAMPLES OF ARC-WELDING JOBS 167 
 
 change during 48 hours, and upon removal of the load at the 
 end of that period a set of less than 0.01 ft. was measured. 
 
 Speed of Arc Welding. In a paper read before the Ameri- 
 can Institute of Electrical Engineers, New York, Feb. 20, 1919, 
 H. M. Hobart says: 
 
 All sorts of values are given for the speed, in feet per hour, with 
 which various types of joints can be welded. Operators making equally 
 good welds have widely varying degrees of proficiency as regards speed. 
 Any quantitative statement must consequently be of so guarded a character 
 as to be of relatively small use. In general, and within reasonable limits, 
 the speed of welding will increase considerably when larger currents arc 
 employed. It appears reasonable to estimate that this increase in speed 
 will probably be about 25 to 35 per cent for high values of current. This 
 increase is not directly proportional to the current employed because a 
 greater proportion of time is taken to insert new electrodes and the operator 
 is working under more strenuous conditions. Incidentally, the operator 
 who employs the larger current .'Will not only weld quicker but the weld 
 will have also better strength and ductility. 
 
 On this point Mr. Wagner writes as follows: 
 
 I would not say that speed in arc welding was proportional to the 
 current used. Up to a certain point ductility and strength improve with 
 increased current, but when these conditions are met, we do not obtain 
 the best speed due to increased heating zone and size of weld puddle. 
 Speed may fall off when current is carried beyond certain points. 
 
 In a research made by William Spraragen for the Welding Research 
 Sub-Committee on several tons of half-inch-thick ship plate, the average 
 rate of welding was only two feet per hour. Highly skilled welders were 
 employed, but they were required to do the best possible work, and the 
 kinds of joints and the particular matters under comparison were very 
 varied and often novel. 
 
 However, in the researches carried on by Mr. Spraragen it was found 
 that about 1.9 Ib. of metal was deposited per hour using a 5 / 32 -in. bare 
 electrode and with the plates in a flat position. The amount of electrodes 
 used up was about 2.7 Ib. per hour, of which approximately 16.5 per cent 
 was wasted as short ends and 13 per cent burnt or vaporized, the remainder 
 being deposited at the speed of 1.9 Ib. per hour mentioned above. 
 
 For a 12-ft.-cube tank of Hn. thick steel welded at Pittsfield, the 
 speed of welding was 3 ft. per hour. The weight of the steel in this 
 tank was 16,000 Ib. and the weight of electrode used up was 334 Ib. of 
 which 299 Ib. was deposited in the welds. The total welding time was 
 165 hours corresponding to using up electrodes at the rate of just 2 Ib. 
 per hour. The total length of weld was 501 ft., the weight of electrode 
 used up per foot of weld thus being 0.60 Ib. The design of this tank 
 comprised eighteen different types of welded joint. Several different 
 
168 ELECTRIC WELDING 
 
 operators worked on this job and the average current per operator was 
 150 amp. 
 
 For the British 125-ft.-long Cross-Channel Barge for which the shell 
 plating was composed of V 4 -in. and 5 / M -in. thick plates, described in H. 
 Jasper Cox's paper read before the Society of Naval Architects on Nov. 
 15, 1918, and entitled ' ' The Application of Electric Welding to Ship Con- 
 struction," it is stated that: ''After a few initial difficulties had been 
 overcome, an average speed of welding of 7 ft. per hour was maintained 
 including overhead work which averaged from 3 to 6 ft. per hour. ' ' 
 
 In a report appearing on page 67 of the minutes and records of the 
 Welding Kesearch Sub-Committee for June 28, 1918, O. A. Payne, of the 
 British Admiralty, states: "A good welder could weld on about one pound 
 of metal in one hour with the No. 10 Quasi-Arc electrode, using direct 
 current at 100 volts. An electrode containing about 1 oz. of metal is 
 used up in about 3 minutes, but this rate cannot be kept up continously. " 
 
 The makers of the Quasi-Arc electrode publish the following data for 
 the speed of arc welding in flat position with butt joints, a 60-deg. angle 
 and a free distance of |-in. 
 
 Thickness 
 of Plates 
 I. in 
 
 Speed in Feet 
 per Hour 
 30 
 
 4 in . 
 
 18 
 
 i in. . . . . 
 
 6 
 
 1 in 
 
 1.3 
 
 I cannot, however, reconcile the high speed of welding -in. plate 
 published in this report as 6 ft. per hour, with the report given above 
 by the British Admiralty that a good welder deposits 1 Ib. of metal per 
 hour with the Quasi-Arc electrode. If the rate given by the manufacturer 
 is correct, it would mean that about four pounds of metal were deposited 
 per hour. On this basis the rate must have been computed on the time 
 taken to melt a single electrode and not the rate at which a welder could 
 operate continuously, allowing for his endurance and for the time taken 
 to insert fresh electrodes in the electrode holder and the. time taken for 
 cleaning the surface of each layer before commencing the next layer. 
 From his observations I am of the opinion that a representative rate for 
 a good welder lies about midway between these values given respectively 
 by Mr. Payne, and by the makers of the Quasi-Arc electrode, say for 
 -in. plates some 2 Ib. per hour. This, it will be observed, agrees with 
 Mr. Spraragen's experience in welding up some 6 tons of ^-in. ship plate 
 with a dozen or more varieties of butt joint and Mr. Wagner's results with 
 an 8-ton tank. Even this rate of 2 Ib. per hour is only the actual time 
 of the welding operator after his plates are clamped in position. This 
 preliminary work and the preparation of the edges which is quite an under- 
 taking, and requires other kinds of artisans, accounts for a large amount 
 of time and should not be under-estimated. 
 
 The practice heretofore customary of stating the speed of welding in 
 
EXAMPLES OF ARC-WELDING JOBS 169 
 
 feet per hour has led to endless confusion as it depends on type of joint, 
 height of weld and various details. A much better basis is to express 
 the speed of welding in pounds of metal deposited per hour. Data for 
 the pounds of metal deposited per hour are gradually becoming quite definite. 
 The pounds of metal per foot of weld required to be deposited can be 
 readily calculated from the drawings or specifications. With the further 
 available knowledge of the average waste in electrode ends and from other 
 causes, the required amount of the electrode material for a given job can be 
 estimated. 
 
 Suitable Current for Given Cases. For a given type of weld, for 
 example, a double V-weld in a -in. thick ship plate, it was found that 
 in the summer of 1918, while some operators employed as low as 100 amp., 
 others worked with over 150 amp. Some, in making such a weld, employed 
 electrodes of only |-in. diameter and others preferred electrodes of twice 
 as great cross-section. For the particular size and design of weld above 
 mentioned, the Welding Kesearch Sub-Committee had welds made with 200 
 to 300 amp. The conclusion appears justified that the preferable current 
 for such a weld is at least 200 amp. If the weld of the -in.-thick plate 
 is of the double-bevel type, some 50 amp. less current should be used for 
 the bottom layer than is used for the second layer, if two layers are 
 used. For f-in.-thick plates, the most suitable welding current is some 
 300 amp. This is of the order of twice the current heretofore usually 
 employed for such a weld. 
 
 Mr. Wagner writes: 
 
 We have made a number of tests to determine the effect of varying 
 current on the strength of the weld. Tests were made on a -in. plate 
 with current values as follows: 80, 125, 150, 180, 220, 275 and 300 amp. 
 These tests show improvement in the tensile strength and bending qualities 
 of welds as the current increases. The speed of welding increases up to a 
 certain point and then decreases. 
 
 Effect on Arc Welding of Voltage Employed. We have made a number 
 of tests to determine the influence of variable voltages on the strength 
 and character of electric welds. The experiments were made welding -in. 
 plate with 150 amp. held constant and voltage varying as follows: 40, 75, 100, 
 125, 150, 200 and 225 volts. This test demonstrates that there is no material 
 difference in the tensile strength, bending qualities or the appearance of 
 the welded- in material. There is this advantage, however, in the higher 
 voltage, that variations in the strength of the arc do not materially affect 
 the value of the current. A curve-drawing ammeter was installed on the 
 welding circuit which showed variations in current at 75 volts, but at 150 
 volts the current curve was practically a straight line. 
 
 Preferable Size of Electrode. On certain railways, a single diameter 
 of electrode is employed independently of the size or shape of the plates 
 or parts being welded. The experience of other people leads them to make 
 use of several different sizes of electrodes according to the size of the 
 job and the type of joint. Present British practice appears to be to use 
 
170 ELECTRIC WELDING 
 
 such a size of electrode as to have a current density of some 4,000 to 
 6,000 amp. per square inch. The investigations of the Welding Research 
 Sub-Committee indicate that at least 10,000 to 12,000 amp. per square inch 
 is suitable for electrodes of y 8 -in. and 5 / 32 -in. diameter and well up toward 
 10,000 amp. per square inch for electrodes of 8 /i 6 -in. and 3 / 4 -in. diameter. 
 
CHAPTER IX 
 PHYSICAL PROPERTIES OF ARC-FUSED STEEL 
 
 The work of the Bureau of Standards in investigating the 
 physical properties of arc-fused steel, was described in Chemical 
 and Metallurgical Engineering, by Henry S. Rowdon, Edward 
 Groesbeck and Louis Jordan. This was by special permission 
 of Director Stratton. The article was substantially as follows : 
 
 During the year 1918 at the request of and with the co- 
 operation of the welding research sub-committee of the 
 Emergency Fleet Corporation an extensive program was outlined 
 by the Bureau of Standards for the study of are-welding. 
 Due to changed conditions, however, at the close of the year 
 1918, the original program was modified and shortened very 
 considerably. In drawing up the modified program, it was 
 decided to make the study of the characteristic properties 
 of the fused-in metal the primary object of the investigation, 
 the study of the merits of the different types of electrodes 
 being a secondary one. Since the metal of any weld produced 
 by the electric-arc fusion method is essentially a casting, as 
 there is no refinement possible as in some of the other methods, 
 it is apparent that the efficiency of the weld is dependent upon 
 the properties of this arc-fused metal. Hence a knowledge of 
 its properties is of fundamental importance in the study of 
 electric-arc welds. 
 
 Preliminary Examinations of Electric- Arc Welds. Numer- 
 ous articles have appeared in technical literature bearing on 
 the subject of electric-arc welding. Most of these, however, 
 are devoted to the technique and comparative merits of the 
 method, manipulations, equipment, etc., rather than to the 
 study of the characteristics of the metal of the weld itself. 
 The information on this phrase of the subject is rather meager. 
 
 A considerable number of examinations were made of welds 
 'prepared by means of the electric-arc process and representa- 
 tive of different conditions of welding. 
 
 171 
 
172 ELECTRIC WELDING 
 
 Most of these were of a general miscellaneous nature and 
 the results do not warrant including a description of the 
 different specimens here. One series of particular interest, 
 however, may well be referred to in detail. As part of this 
 study the welding research sub-committee submitted to the 
 Bureau of Standards a number of welds of ship-plate repre- 
 sentative of English practice for examination, some of which 
 were considered as very superior examples of welding as well 
 as others of a decidedly inferior grade. In Tables VII and 
 VIII are given the results obtained by the mechanical tests 
 made upon these specimens. The welding was done by skilled 
 operators by means of special brands of electrodes (welding 
 pencils), the trade names of which, however, have been omitted 
 from the tables. The specimens were examined microscopically 
 very carefully, in addition to the mechanical tests made. The 
 results are not included, however, as the structural features 
 of the material did not differ from those to be discussed in 
 another chapter. The results of the mechanical tests given 
 are of value in that they are indicative of the average 
 mechanical properties which should be expected in electric-arc 
 welds of satisfactory grade for the shape and size of those 
 examined. 
 
 Method of Building Specimens. The specimens required 
 for the study of the mechanical properties of the arc-fused 
 metal were prepared for the most part at the Bureau of 
 Standards, direct current being used in the operation. The 
 apparatus used is shown dia grammatically in Fig. 149. By 
 means of the adjustable water rheostat the current could be 
 increased progressively from 110 to 300 amp. By the use of 
 automatic recording instruments the voltage and current were 
 measured and records were taken at intervals during the 
 preparation of a specimen. The values of current given in 
 the tables are those which were desired and were aimed at. 
 The average deviation from this value as recorded by the 
 curves was approximately 5 amp. The value of the current 
 at the instant "the arc was struck'* was of course many times 
 the normal working value used during the fusion. 
 
 Since the investigation was concerned primarily with the 
 properties of the arc-fused metal, regular welds were not made. 
 Instead the metal was deposited in a block large enough to 
 
PHYSICAL PROPERTIES OF ARC-FUSED STEEL 
 
 173 
 
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 ELECTRIC WELDING 
 
 permit a tension specimen (0.505 in. diameter, 2 in. gage length) 
 to be machined out of it. Although the opinion is held by 
 some welders that the properties of the metal of an arc-weld 
 are affected materially by the adjacent metal by reason of 
 the interpenetration of the two, it was decided that the change 
 of properties of the added metal induced by the fusion alone 
 was of fundamental importance and should form the basis 
 of any study of arc-welding. The method adopted also per- 
 mitted the use of larger specimens with much less machining 
 
 -Weight 
 
 HO V. 
 DC. 
 
 A tfj us to hie Wa ter ffheos fat 
 ?/o Sodium Chloride 
 Solution 
 
 feet Welding 
 ToblQ . 
 
 FIG. 149. Arrangement of Apparatus for Welding. 
 
 than would have been possible had the metal been deposited 
 in the usual form of a weld. 
 
 In the first few specimens prepared (ten in number) the 
 metal was deposited by a series of '"headings" inside a l^-in. 
 angle iron. The tension specimens cut from the deposited 
 metal were found to be very inferior and entirely unsuitable 
 for the study. This was largely on account of the excessive 
 overheating which occurred as well as the fact that a relatively 
 "long arc" was necessary for the fusion in this form. Because 
 of the very evident inferiority of these specimens, the results 
 of the mechanical tests made are not given in the tables. 
 The method of deposition of the metal was then changed to 
 
PHYSICAL PROPERTIES OF ARC-FUSED STEEL 
 
 175 
 
 that shown in Fig. 150. This method also had the advantage 
 in that the amount of necessary machining for shaping the 
 specimens for test was materially reduced. The block of arc- 
 
 Side View 
 
 12"- >, 
 
 End View 
 FIG. 150. Method of Formation of the Blocks of Arc-Fused Metal. 
 
 fused metal was built up on the end of a section of J-in. 
 plate of mild steel (ship plate) as shown. When a block of 
 sufficient size had been formed, it, together with the portion 
 
 FIG. 151. Block of Arc-Fused Metal with Tension Specimen Cut from It. 
 Approximately Half Natural Size. 
 
 of the steel plate immediately beneath, was sawed off from 
 the remainder of the steel plate. The tension specimen was 
 turned entirely out of the arc-fused metal. No difficulty what- 
 ever was experienced in machining the specimens. Fig. 151 
 
176 ELECTRIC WELDING 
 
 shows the general appearance of the block of fused metal as 
 well as the tension specimen turned out of it. 
 
 In general in forming the blocks, the fused metal was 
 deposited as a series of " beads" so arranged that they were 
 parallel to the axis of the tension specimen which was cut 
 later from the block. In two cases, for purposes of comparison, 
 the metal was deposited in " beads" at right angles to the 
 length of the specimen. In all the specimens, after the deposi- 
 tion of each layer, the surface was very carefully and vigor- 
 ously brushed with a stiff wire brush to remove the layer of 
 oxide and slag which formed during the fusion. There was 
 found to be but little need to use the chisel for removing this 
 layer. 
 
 Two types of electrodes were used as material to be fused. 
 These differed considerably in composition as shown in Table 
 IX, and were chosen as representative of a "pure" iron and 
 a low-carbon steel. The two types will be referred to as "A" 
 and "B" respectively in the tables. They were obtained in the 
 following sizes: Y 8 , 5 / 32 , 3 / 16 an d V 4 i n - ("A" electrode 5 /ic 
 in. ) . It was planned to use the different sizes with the follow- 
 ing currents: Y 4 in. 75, 110 and 145 amp.; 5 / 32 i n - 145, 185 
 and 225 amp.; 3 / 16 in. 185, 225 and 260 amp.; y 4 in. ( 5 /ie 
 in.) 300 amp. The electrodes were used both in the bare 
 condition and after being slightly coated with an oxidizing 
 and refractory mixture. For coating, a "paste" of the follow- 
 ing composition was used: 15 g. graphite, 7.5 g. magnesium, 
 4 g. aluminium, 65 g. magnesium oxide, 60 g. calcium oxide. 
 To this mixture was added 120 c.c. of sodium silicate (40 deg. 
 Be.) and 150 c.c. of water. The electrodes were painted on 
 one side only with the paste. The quantity given above was 
 found to be sufficient for coating 500 electrodes. The purpose 
 of the coating was to prevent excessive oxidation of the metal 
 of the electrode during fusion and to form also a thin protective 
 coating of slag upon the fused metal. 
 
 Tension specimens only were prepared from the arc-fused 
 metal. It is quite generally recognized that the tension test 
 falls very short in completely defining the mechanical proper- 
 ties of any metal; it is believed, however, that the behavior 
 of this material when stressed in tension is so characteristic 
 that its general behavior under other conditions of stress, 
 
PHYSICAL PROPERTIES OF ARC-FUSED STEEL 
 
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178 ELECTRIC WELDING 
 
 particularly when subjected to the so-called dynamic tests 
 i.e., vibration and shock can be safely predicted from the 
 results obtained. In order to supplement the specimens made 
 at the Bureau a series of six were also prepared by one of 
 the large manufacturers of equipment for electric welding to 
 be included in the investigation. These are designated as 
 "C" in the tables. 
 
 In Table IX it will be noted that the general effect of 
 the fusion is to render the two materials used for welding 
 pencils more nearly the same in composition. The loss of 
 carbon and of silicon is very marked in each case where these 
 elements exist in considerable amounts. A similar tendency 
 may be noted for manganese. The coating with which the 
 electrodes were covered appears to have but little influence, 
 if any, in preventing the oxidation of the carbon and other 
 elements. 
 
 TABLE X RELATION BETWEEN NITROGEN-CONTENT AND CURRENT 
 
 DENSITY * 
 
 Size of 
 
 
 
 
 Elec.- Amperes Cunent 
 trode. In. (Approx) Density 
 
 NitrogenContent (Per Centt) 
 A" Spec. "B" Spec. "C" Spec. Average 
 
 t 110 9,000 
 
 156 
 149 
 
 0.152 \ .... 
 0.141 J 
 
 138 
 
 J 145 11,800 
 
 127 
 140$ 
 
 0.132 \ 
 I35 f 
 
 126 
 
 A 145 7,600 
 
 0.140 
 121 
 
 124 \ 
 122 1 
 
 0.127 
 
 A 185 9,650 
 
 123 
 I19.J 
 
 121 \ 
 1&3II 
 
 131 
 
 
 
 I32j: 1 
 
 
 A 225 11,700 
 
 124 
 M3 
 
 117 \ 
 123 | 
 
 : 
 
 A 175 9.100 
 
 
 ( 133 
 
 b 
 
 
 
 \ 098 
 
 
 A 185 6.700 
 
 0.126 
 127 
 
 119 \ 
 0. 106 | 
 
 120 
 
 A 225 8,150 
 A 260 9,400 
 
 131 
 I3I 
 133 
 10.134 
 
 0.111 
 108 I 
 0.112 \ 
 0.094 / 
 
 120 
 0.118 
 
 A 300 3,900 
 
 117 
 10 Ml 
 
 
 114 
 
 * Credit due J. R. Cain. 
 
 
 
 
 t Average of two determinatio 
 
 is. 
 
 
 
 j Included in average for C-D 1 1 ,800. 
 Coated electrodes. 
 
 6 Included in average for C-D 9,000. 
 a Average of 9 determinations. 
 
 The most noticeable change in composition is the increase 
 in the nitrogen content of the metal. In general the increase 
 was rather uniform for all specimens. In Table X are sum- 
 marized the results of the nitrogen determinations together 
 
PHYSICAL PROPERTIES OF ARC-FUSED STEEL 179 
 
 TABLE XI TENSILE PROPERTIES OF ELECTRODES 
 
 - Electrode* 
 
 Ulto. 
 
 -Proper. 
 
 Elong. 
 
 Reduct. 
 
 
 Size. 
 In. 
 
 Strength, 
 Lb. Sq.In. 
 
 Limit, 
 Lb. Sq.In. 
 
 in 2 In. 
 Per Cent 
 
 Area, 
 Per Cent 
 
 A 
 
 A 
 
 65,800 
 
 39,000 
 
 16.5 
 
 69 2 
 
 A 
 
 1 
 
 62,100 
 
 48.000 
 
 9.0 
 
 69.3 
 
 A 
 
 A 
 
 60,100 
 
 34,500 
 
 14 
 
 66 4 
 
 A 
 
 A 
 
 57,300 
 
 
 15 5 
 
 67 6 
 
 B 
 
 & 
 
 88,600 
 
 67,000 
 
 45 
 
 51. J 
 
 B 
 
 A 
 
 84,700 
 
 58,500 
 
 7.0 
 
 59 8 
 
 R 
 
 i 
 
 66,300 
 
 37,500 
 
 15.0 
 
 61 4 
 
 B 
 
 i 
 
 67,900 
 
 
 15 5 
 
 62.4 
 
 with the corresponding current density used for the fusion 
 of the metal. In Fig. 152 the average nitrogen contents found 
 for the different conditions of fusion are given and plotted 
 against the corresponding current density. Though no definite 
 conclusion seems to be warranted, it may be said that, in 
 
 0.150 
 
 0.130 
 
 0.110 
 
 0.090 
 
 12,000 
 
 ?00 6000 8000 10,000 
 
 Current Density .Amperes per Sq.In. 
 
 FIG. 152. Relation of Current Density to Nitrogen Content in 
 
 Arc-Fused Jron. 
 Black dots represent averages. 
 
 general, the percentage of nitrogen taken up by the fused 
 iron increases somewhat as the current density increases. With 
 the lowest current densities used the amount of nitrogerTwas' 
 Touncf to ^ecrease~~KppTGci ably . 
 
 Mechanical Properties of the Arc-Fused Metal. The 
 mechanical properties of the two types of electrodes used as 
 determined by the tension test are summarized in Table XL 
 
180 
 
 ELECTRIC WELDING 
 
 TABLE XII TENSILE PROPERTIES AND HARDNESS OF FIFTY SPECIMENS 
 OF WELD-METAL AT THE BUREAU. (0.505-iN. DIAM. STANDARD TENSION 
 BAR USED) 
 
 Bare Electrodes 
 
 Tensile Properties 
 
 1 
 
 1 
 
 1 
 
 ! 
 
 6 1 
 
 d 
 
 I 
 
 1 
 
 <** 
 
 8 
 
 i 
 
 & 
 
 fi 
 
 1 * 
 
 | 
 
 c 
 
 "J 
 
 ^ 
 
 1 i 
 
 i 
 
 2 l 
 
 5 > 
 
 1 
 
 |j 
 
 go 
 
 i 
 
 c 
 
 CO 
 
 A2 
 
 110 
 
 49,850 36,600 
 
 25.000 
 
 60 
 
 65 
 
 108 
 
 A3 
 
 145 
 
 51.950 36,250 
 
 30,000 
 
 80 
 
 13 
 
 114 
 
 fl fc 
 
 145 
 185 
 
 47.550 
 48.100 , 
 
 
 6.0 
 8.0 
 
 74 
 87 
 
 108 
 104 
 
 A9 A 
 
 225 
 
 45,500 '.:. . 
 
 
 80 
 
 96 
 
 io< 
 
 A4 A 
 
 185 
 
 50,600 33,750 
 
 29,500 
 
 5.5 
 
 13 5 
 
 105 
 
 A5 A 
 
 225 
 
 49,150 36,250 
 
 22,000 
 
 7.0 
 
 10 
 
 102 
 
 A6 A 
 
 260 
 
 50.950 33,750 
 
 28,800 
 
 10.5 
 
 12.0 
 
 107 
 
 AIO A 
 
 300 
 
 46,670 ..... 
 
 
 12.0 
 
 119 
 
 104' 
 
 Covered Electrodes 
 
 AD2 j 
 
 110 
 
 51,250 35,000 
 
 25,600 
 
 9.5 
 
 II. 
 
 103 
 
 AD2-D 
 
 no 
 
 43,000 
 
 23.000 
 
 50 
 
 90 
 
 
 AD3 
 
 MS 
 
 51,100 33,750 
 
 25,000 
 
 8.5 
 
 10*5 
 
 110 
 
 AD3-D 
 
 145 
 
 46,250 . .. 
 
 24.250 
 
 7.0 
 
 12 
 
 
 AD7 A 
 
 145 
 
 41,750 
 
 
 60 
 
 66 
 
 99 
 
 AD7-D A 
 
 145 
 
 46,950 
 
 25.500 
 
 80 
 
 94 
 
 
 AD8 A 
 
 185 
 
 44,620 
 
 
 6.5 
 
 58 
 
 103 
 
 AD8-D A 
 
 185 
 
 43,600 
 
 23,250 
 
 6.5 
 
 9 
 
 
 AD9 A 
 
 225 
 
 46,900 
 
 
 95 
 
 10 1 
 
 96 
 
 AD9-D A 
 
 225 
 
 41,550 
 
 25,500 
 
 5.0 
 
 6.5 
 
 
 AD4 A 
 
 185 
 
 51,200 35,000 
 
 30,000 
 
 10.5 
 
 10.5 
 
 101 
 
 AD4-D A 
 
 185 
 
 45,700 
 
 25,500 
 
 8.5 
 
 11.5 
 
 
 AD5 A 
 
 225 
 
 48.600 35,000 
 
 30,000 
 
 7.0 
 
 10 
 
 '96 
 
 AD5-D A 
 
 225 
 
 46.250 
 
 23,750 
 
 11.5 
 
 12 
 
 
 AD6 A 
 
 260 
 
 47,500 34,500 
 
 31,500 
 
 9.0 
 
 9.0 
 
 97 
 
 AD6-D A 
 
 260 
 
 50,700 
 
 
 8.0 
 
 28 
 
 105 
 
 ADIO A 
 
 300 
 
 45,900 
 
 
 8.5 
 
 11.5 
 
 98 
 
 Bare Electrodes 
 
 B2 i 
 
 110 
 
 52,650 37,000 
 
 27,000 
 
 7.5 
 
 7.5 
 
 1 14 
 
 B3 i 
 
 145 
 
 54,500 36,000 
 
 27,000 
 
 12 5 
 
 12 
 
 106 
 
 B4 A 
 
 145 
 
 46,450 33,500 
 
 26,000 
 
 50 
 
 7 
 
 102 
 
 
 185 
 
 49,600 34,250 
 
 27,000 
 
 75 
 
 9 
 
 108 
 
 B6 A 
 
 225 
 
 49,500 30,500 
 
 28,000 
 
 90 
 
 5 
 
 110 
 
 j? 
 
 185 
 
 47,550 
 
 28,500 
 
 75 
 
 11.5 
 
 95 
 
 B8 A 
 
 225 
 
 42,900 
 
 18,750 
 
 75 
 
 16.2 
 
 101 
 
 B9 A 
 
 260 
 
 47,500 
 
 21,500 
 
 12 
 
 13 5 
 
 102 
 
 Covered Electrodes 
 
 BD2 } 
 
 110 
 
 49,050 33,750 
 
 27,500 
 
 9.0 
 
 12.0 
 
 100 
 
 BD2-D 
 
 110 
 
 44,400 
 
 20,000 
 
 6.5 
 
 9.4 
 
 
 BD3 
 
 145 
 
 52,100 34.300 
 
 30,500 
 
 12 5 
 
 16 
 
 116 
 
 BD3-D 
 
 145 
 
 50,850 
 
 23,500 
 
 13 
 
 17 5 
 
 
 BD4 A 
 
 145 
 
 48,130 31,000 
 
 30,500 
 
 8.0 
 
 10 
 
 toi 
 
 BD4-D A 
 
 145 
 
 41,750 
 
 21,000 
 
 6.0 
 
 95 
 
 
 BD5 A 
 
 185 
 
 49,086 31,730 
 
 29,000 
 
 12 5 
 
 130 
 
 97 
 
 BD5-D A 
 
 185 
 
 47,100 
 
 22,500 
 
 II 
 
 12 5 
 
 
 BD6 A 
 
 225 
 
 45,500 30,500 
 
 25,000 
 
 8 5 
 
 10 5 
 
 95 
 
 BD7 A 
 
 185 
 
 49,950 
 
 24,500 
 
 II 5 
 
 21 5 
 
 98 
 
 BD7-D A 
 
 185 
 
 51,150 
 
 23,750 
 
 14 5 
 
 19 5 
 
 
 BD8 A 
 
 225 
 
 41,500 
 
 17,850 
 
 6.0 
 
 12 7 
 
 99 
 
 BD8-D(?) A(?) 
 
 225(?) 
 
 48,750 
 
 21,250 
 
 12.5 
 
 16 
 
 
 BD9 A 
 
 260 
 
 46,350 
 
 24,000 
 
 10.0 
 
 15 
 
 99 
 
 Bare Electrodes 
 
 Cl A 
 
 175 
 
 48,650 32,650 
 
 23,000 
 
 12.0 
 
 19 1 
 
 
 C2 A 
 
 175 
 
 45,200 32,400 
 
 23,000 
 
 7.5 
 
 16.6 
 
 
 85 * 
 
 175 
 175 
 
 49,720 32,650 
 54,500 32,500 
 
 25,000 
 25,000 
 
 90 
 110 
 
 13.6 
 17 5 
 
 118 
 
 C5 A 
 
 175 
 
 50,900 32,500 
 
 24,000 
 
 15 
 
 23.0 
 
 109 
 
 C6 A 
 
 175 
 
 50.500 33.500 
 
 23.000 
 
 12 
 
 16 
 
 
PHYSICAL PROPERTIES OF ARC-FUSED STEEL 181 
 
 1 
 
 [1 
 
 
 M 
 
 
 
 P 
 
 <J 
 
 PQ 
 
 ' | 
 
 Jl 
 
 vc^.>o 1^1 oo m o <N . -m 
 
 Jj'C -o o o 9- o o-o 
 
 : i 
 
 < 
 
 H 
 9 
 
 H 
 
 {H 
 
 M 
 
 ll 
 
 ( 
 
 OCBC - - ^__ 
 
 4*fi*^ S -o -o " '*"' '"~ ->o ->o **** ' * 
 
 {j JjflC 
 
 g c oo -t- oo < m r>i rx ^-vO 
 Jj-~ o o o o o o o oo 
 
 i 
 
 " B 
 > -S 
 < 
 
 Q 
 
 M 
 
 8 
 
 \ 
 
 CCOQ ~ 
 
 -5 
 
 S 
 
 \ 
 
 
 
 1 
 
 1 
 
 
 
 hJ 
 
 ^g 
 I* 5 
 
 "5 !r 
 
 
 5 
 
 1 
 
 5 s - 
 
 
 <0 -o 
 
 1 
 
 1 
 
 <u S ~ : _o 
 
 * <X 
 
 s 
 
 
 .^^ 
 
 4 S 
 
 ^ a 
 8 
 
 *l 
 
 w S 
 
 -' e 
 
 <N 
 
 q "c 
 
 ^^om^^-oo ___ >A -o -o . -o> 
 
 
 
 O oo 
 
 * ~r 
 
 s 
 
 3 S 
 
 1<3 
 
 1 ^ - "* " ^* ^ ++ 2J : 
 
 c 
 ^ 
 
 PERTIES AND HARDNESS OF FlFTY SPE 
 
 ARRANGED TN ORDER OF A 
 
 Tensile Properties 
 Yield Point . Elongat 
 Lb. Sq.ln. pei 
 
 JO O o m * -o ! " 'O 
 o in <N .S . : . . . jn 
 
 ' l " f0 ++ . . . g+t .*- t ' l ' + S' IH ' -S 
 i "H t. -. *2 
 
 Q * f^ e\ ...*> ** -V 
 
 ! 
 
 O O ..... o . O o 'O 
 
 BS ' "^ Q "^ 
 1 5 *3 ^ ' **- :co - 
 
 Av 35,000 Av. 33.250 Av. 7.9 
 lectrodes used (Table III) 
 = 110 amps, and 145(1) amps. & tn. rft'am. 145 
 P 
 
 o 
 
 H 
 
 M 
 
 ^1 "5^-5o--rC*'- S . ' S - :5 : : i< 
 
 lo|l 
 
 ft 
 
 S 
 
 g C-3 
 
 v lfTVTg g -- 
 
 35! 
 
 
 
 ^j 
 
 * 
 
 ^ S 3; 5 S 5 5 S : :? 
 
 
 S 
 
 1* 
 
 goc; ^ooooooooo o oooo 
 
 5Jl|S 
 
 J, 
 
 HH 
 
 H 
 
 S 
 
 m 
 E^ 
 
 <: 
 
 ll 
 
 < 
 
 si o ^ ^ ^~ o oS 
 
 ^~ C9* H 
 
182 ELECTRIC WELDING 
 
 In Table XII are given the results of the mechanical tests 
 made upon the tension specimens which were turned out of the 
 blocks of metal resulting from the fusion of the elec- 
 trodes. 
 
 The specimens listed, C x , C 2 . . . . C c are the six which were 
 prepared outside the Bureau and submitted for purposes of 
 comparison. It was stated that they were prepared from bare 
 electrodes 5 / 32 in. diameter of type "B," containing 0.17 per cent 
 carbon and 0.5 per cent manganese. 
 
 As an aid for more readily comparing the mechanical prop- 
 erties of the two types of arc-fused metal "A" and "B," the 
 results have been grouped as given in Table XIII. 
 
 The characteristic appearance of specimens after testing, 
 illustrating their behavior when stressed in tension till rupture 
 occurs is shown in Fig. 153. These represent two views of 
 the face of the fracture, one in which the line of vision is 
 perpendicular to the face, the other at an angle of 45 deg., 
 together with a side view of the cylindrical surface of the 
 specimen. The features shown are characteristic of all the 
 specimens tested, though in some they were much more pro- 
 nounced than those shown. The fracture of the specimen in 
 all cases reveals interior flaws. In some of the specimens, 
 however, these are microscopic and of the character to be 
 discussed in a subsequent chapter on Metallography. Although 
 many of the specimens (from the results of Table XII) appear 
 to have a considerable elongation, it is seen from Fig. 153 
 that the measured elongation does not truly represent a prop- 
 erty of the metal itself. It is due rather to interior defects 
 which indicate lack of perfect union of succeeding additions 
 of metal during the process of fusion. The surface markings 
 of the specimen after stressing to rupture are very similar 
 to those seen in the familiar "flaky steel." 
 
 Resulting Physical Properties Depend Essentially on Sound- 
 ness. It appears from the results above that, as far as the 
 mechanical properties are concerned, nothing was gained by 
 coating the electrodes. The results show no decided superiority 
 for either of the two types of electrodes used. This may be 
 expected, however, when one considers that the two are rendered 
 
PHYSICAL PROPERTIES OF ARC-FUSED STEEL 183 
 
 practically the same in composition during fusion by the burn- 
 ing out of the carbon and other elements. 
 
 The results of the tension tests upon the "C" series of 
 
 FIG. 153. Characteristic Appearance of Tension Specimen After Test. 
 
 At top, face of fracture, viewed normally. Middle, fractured end of specimen, 
 viewed at an angle of 45 deg. At bottom, cylindrical surface of specimen. Mag- 
 nification, X 2. 
 
 specimens which were made outside of the Bureau and sub- 
 mitted to be included in the investigation, show no marked 
 difference between these samples and those prepared by the 
 Bureau. In all cases the results obtained in the tension test 
 
184 ELECTRIC WELDING 
 
 are determined by the soundness of the metal and do not 
 necessarily indicate the real mechanical properties of the 
 material. 
 
 The results of the hardness determinations do not appear 
 to have any particular or unusual significance. The variations 
 are of the same general nature and relative magnitude as the 
 variations observed in the results of the tension test. In 
 general the higher hardness number accompanies the higher 
 tensile values, though this was not invariably so. As previously 
 noted, specimens were prepared for the purpose of showing 
 the relation between the direction in which the stress is applied 
 and the manner of deposition of the metal. The metal was 
 deposited in the form shown in Fig. 151, except that the 
 "beads" extended across the piece rather than lengthwise, 
 hence the "beads" of fused metal were at right angles to the 
 direction in which the tensional stress was applied. The results 
 of the tension tests show that these two specimens (AW t and 
 AW 2 ) were decidedly inferior to those prepared in the other 
 manner as shown in Table XIV. 
 
 TABLE XIV. MECHANICAL PROPERTIES OF ARC-FUSED METAL DEPOSITED 
 AT EIGHT ANGLES TO LENGTH OF SPECIMEN 
 
 Specimen 
 
 Ult. 
 Strength, 
 Lb. Sq. In. 
 
 Proportional 
 Limit, 
 Lb. Sq. In. 
 
 Elongation 
 in 2 in. (per 
 Cent) 
 
 Bed. of Area, 
 per Cent 
 
 AW 1 
 
 40,450 
 
 22,500 
 
 6.5 
 
 8.5 
 
 AW 2 
 
 39,500 
 
 22,500 
 
 4.0 
 
 3.0 
 
 Macrostructure. The general condition of the metal result- 
 ing from the arc-fusion is shown in Figs. 154 and 155, which 
 show longitudinal median sections of a series of the tension 
 bars adjacent to the fractured end. The metal in all of these 
 specimens was found to contain a considerable number of 
 cavities and oxide inclusions, these are best seen after the 
 surfaces are etched with a 10 per cent aqueous solution of 
 copper-ammonium chloride. In many of the specimens the 
 successive additions of metal are outlined by a series of very 
 fine inclusions (probably oxide) which are revealed by the 
 etching. There appears to be no definite relation between the 
 soundness of the metal and the conditions of deposition i.e., 
 for the range of current density used nor does either type 
 
PHYSICAL PKOPEKTiES OF ARC-FUSED STEEL 185 
 
 FIG. 154. Macrostructure of Arc-Fused Metal, Type A. 
 
 Medial Longitudinal sections of the tension bars indicated were used 
 XII) ; etching, 10 per cent aqueous solution of copper-ammonium chloride. 
 nification, X 2. From top to bottom in order: 
 
 Ai)6 A electrode; iMo in., covered, 260 amp. 
 
 A5 A electrode; iMe in., bare, 225 amp. 
 
 A6 A electrode; Me in., bare, 260 amp. 
 
 A3 A electrode; i in., bare, 145 amp. 
 
 A4 A electrode; Me in., bare, 185 amp. 
 
 AD2 A electrode; i in., covered, 110 amp. 
 
 (Table 
 Mag- 
 
186 
 
 ELECTRIC WELDING 
 
 of electrode used show any decided superiority over the other 
 with respect to porosity of the resulting fusion. In Fig. 156 
 
 Fie. 155. Macrostructure of Arc-Fused Metal, Type B. 
 
 Medial longitudinal sections of the tension bars indicated were used (Table XII) ; 
 etching, 10 per cent aqueous solution of copper-ammonium chloride. Magnification, 
 X 2. From top to bottom in order: 
 
 B4 B electrode; %2 in., bare, 145 amp. 
 B5 B electrode; %z in., bare, 185 amp. 
 B2 B electrode; J in., bare, 110 amp. 
 B3 B electrode; | in., bare, 145 amp. 
 BD6 B electrode; 5 /te in., covered, 225 amp. 
 BD4 B electrode; %'i in., covered, 14T> amp. 
 
 is shown the appearance of a cross-section of one of the blocks 
 of arc-fused metal prepared outside of the Bureau by skilled 
 
PHYSICAL PROPERTIES OF ARC-FUSED STEEL 187 
 
 welding operators. The condition of this material is quite 
 similar to that prepared by the Bureau. 
 
 The microscopic study of the material to be discussed in 
 a subsequent chapter also revealed further evidence of unsound- 
 ness in all three types, "A," n B" and "C." 
 
 Discussion of Results. In any consideration of electric-arc 
 welding it should constantly be borne in mind that the weld- 
 
 FIG. 156. Macrostructure of Arc-Fused Metal, Type C. 
 
 Specimen Cl (Table XII), cross-section of the block of arc-fused metal from 
 which the tension bar was turned; etched with 5 per cent alcoholic solution of 
 picric acid. Magnification, X 1.7. 
 
 metal is simply metal which has been melted and has then 
 solidified in situ. The weld is essentially a casting, though 
 the conditions for its production are very different from those 
 ordinarily employed in the making of steel castings. The 
 metal loses many of the properties it possesses when in the 
 wrought form and hence it is not to be expected that a fusion 
 weld made by any process whatever, will have all the proper- 
 ties that metal of the same composition would have when in 
 the forged or rolled condition. A knowledge of the char- 
 
188 ELECTRIC WELDING 
 
 acteristic properties of the arc-fused iron is then of funda- 
 mental importance in the study of the electric-arc weld. 
 
 The peculiar conditions under which the fusion takes place 
 also render the metal of the weld quite different from similar 
 metal melted and cast in the usual manner. It is seemingly 
 impossible to fuse the metal without serious imperfections. 
 The mechanical properties of the metal are dependent there- 
 fore to an astonishing degree upon the skill, care and patience 
 of the welding operator. The very low ductility shown by 
 specimens when stressed in tension is the most striking feature 
 observed in the mechanical properties of the material as 
 revealed by the tension test. As explained above, the measured 
 elongation of the tension specimen does not truly indicate a 
 property of the metal. Due to the unsoundness, already 
 described in the discussion of the structure, the true properties 
 of the metal are not revealed by the tension test to any 
 extent. The test measures, largely for each particular speci- 
 men, the adhesion between the successively added layers which 
 value varies considerably in different specimens due to the 
 unsoundness caused by imperfect fusion, oxide and other inclu- 
 sions, tiny enclosed cavities and similar undesirable features. 
 The elongation measured for any particular specimen is due 
 largely, if not entirely, to the increase of length due to the 
 combined effect of the numerous tiny imperfections which exist 
 throughout the sample. 
 
 That the metal is inherently ductile, however, is shown 
 by the behavior upon bending (later to be discussed) in the 
 microstructure of bent specimens. The formation of slip-bands 
 within the ferrite grains to the extent which was observed 
 is evidence of a high degree of ductility. It appears, however, 
 that the grosser imperfections are sufficient to prevent any 
 accurate measurement of the real mechanical properties of 
 the metal from being made. The conclusion appears to be 
 warranted therefore that the changes of composition which the 
 fusion entails, together with the unusual features of micro- 
 structure which accompany the composition change are of 
 minor importance in determining the strength, durability and 
 other properties of the arc weld. 
 
 In arc-fusion welds in general, the mass of weld-metal is in 
 intimate contact with the parts which are being welded so that 
 
PHYSICAL PROPERTIES OF ARC-FUSED STEEL 
 
 189 
 
 it is claimed by many that because of the diffusion and inter- 
 mingling of the metal under repair with that of the weld, 
 properties of the latter are considerably improved. The com- 
 parison shown in Table XV somewhat supports this claim. The 
 nearest comparison found available with the Bureau's specimen 
 are some of those of the welds designated as the "Wirt- 
 Jones" series reported by H. M. Hobart. These welds were 
 of the 45 deg. double-V type made in ^-in. ship plate; the 
 specimens for test were of uniform cross-section iXi in., the 
 projecting metal at the joint having been planed off even with 
 the surface of the plates and the test bars were so taken that 
 the weld extended transversely across the specimen near the 
 center of its length. The electrodes used were similar to those 
 designated as type "B" in the Bureau's investigation. 
 
 TABLE XV. COMPARISON OF WELDS WITH TESTS OF ARC-FUSED METAL 
 PREPARED UNDER SIMILAR CONDITIONS. 
 
 . Bureau of StanrlorHa 
 
 TXTtw* T^^> 
 
 a 
 
 tie 
 
 C ^ 
 
 1. 
 
 i ' 4- 1 
 
 J e 
 
 |4 
 
 Cu.S 
 
 I 
 
 a 
 
 *F 
 
 c 
 
 H 
 
 ga 
 
 
 K 
 
 B 
 
 gfl 
 
 
 
 i 
 
 c 
 o c 
 
 in" 
 
 5 
 
 6* 
 
 85** 
 
 d 
 
 S""" 
 
 
 * 110 
 
 52.650 
 
 75 
 
 1 
 
 110 
 
 45,800 
 
 8 
 
 Jt 110 
 
 49.050 
 
 90 
 
 1 
 
 115 
 
 58,200 
 
 14 
 
 i* no 
 
 44,400 
 
 6 5 
 
 I 
 
 115 
 
 59,400 
 
 13 
 
 Average 
 
 48,700 
 
 7 7 
 
 1 
 
 120 
 
 53,700 
 
 7 
 
 A 145 
 
 46,450 
 
 5 
 
 
 120 
 
 57,600 
 
 8 
 
 ft 11 145 
 
 A' 45 
 
 48,130 
 41,750 
 
 8 
 
 Average 
 
 150 
 
 54,940 
 60,900 
 
 10 
 8 
 
 Average 
 
 45.440 
 
 6 3 
 
 A 
 
 155 
 
 62,600 
 
 11 5 
 
 A 185 
 
 49.600 
 
 7 5 
 
 A verage 
 
 
 61.750 
 
 9.8 
 
 A 185 
 
 49.086 
 
 12 5 
 
 H 
 
 175 
 
 59.800 
 
 9 
 
 A 185 
 
 47.100 
 
 11 
 
 
 
 
 
 Average 
 
 48.395 
 
 10 3 
 
 
 
 
 
 * Electrodes were 
 
 used in bare condition. 
 
 t Electrodes were coated a 
 this column were used bare 
 
 s previously described 
 
 , those 
 
 not so designated in 
 
 Since the specimens used in work described in the fore- 
 going sections were prepared in a manner quite different from 
 the usual practice of arc-welding, no definite recommendations 
 applicable to the latter can be made. It appears, however, 
 from the results obtained that the two types of electrodes used 
 i.e., "pure" iron and low-carbon steel should give very 
 similar results in practical welding. This is due to the changes 
 which occur during the melting so that the resulting fusions 
 are essentially of the same composition. The use of a slight 
 
190 ELECTRIC WELDING 
 
 coating on the electrodes does not appear to be of any material 
 advantage so far as the properties of the resulting fused metal 
 are concerned. Since the program of work as carried out did 
 not include the use of any of the covered electrodes which 
 are highly recommended by many for use in arc welding, 
 particularly so, for " overhead work," no data are available 
 as to the effect of such coatings upon the properties of the 
 metal resulting from fusion. Although all of the specimens 
 used in the examinations were made by the use of direct 
 current, it appears from the results obtained with a consider- 
 able number of welds representing the use of both kinds of 
 current, submitted for the preliminary examinations which 
 were made, that the properties of the fused metal are inde- 
 pendent of the kind of current and are influenced primarily 
 by the heat of fusion. Any difference in results obtained by 
 welding with alternating current as compared with those 
 obtained with direct current apparently depends upon the rela- 
 tive ease of manipulation during welding rather than to any 
 intrinsic effect of the current upon properties of the metal. 
 
CHAPTER X 
 METALLOGRAPHY OF ARC-FUSED STEEL 
 
 The same authors responsible for the description of the 
 investigations at the Bureau of Standards, given in the previous 
 chapter, also furnished the data given in this chapter: 
 
 Fusion welds evidently are fundamentally different from 
 other types of joints in that the metal at the weld is essentially 
 a casting. A preliminary study of a considerable number of 
 specimens welded under different conditions confirmed the 
 impression that the arc-fusion weld has characteristics quite 
 different from other fusion welds. 
 
 In the present study, of which both the previous chapter 
 and this one form a part, two types of electrodes, a "pure" 
 iron called "A" and a mild steel called "B," were used, in 
 the bare condition, and also after receiving a slight coating. 
 With these were included a set of similar specimens prepared 
 outside of the Bureau by expert welding operators. During 
 the fusion the composition of the metal of the two types of 
 electrodes is changed considerably by the " burning-out " of 
 the carbon and other elements, the two becoming very much 
 alike in composition. A very considerable increase in the 
 nitrogen content occurs at the same time, as shown by chemical 
 analysis. 
 
 The mechanical properties of the arc-fused metal as 
 measured by the tension test are essentially those of an inferior 
 casting. The most striking feature is the low ductility of the 
 metal. All of the specimens showed evidence of unsoundness 
 in their structure, tiny inclosed cavities, oxide inclusions, lack 
 of intimate union, etc. These features of unsoundness are, 
 seemingly, a necessary consequence of the method of fusion 
 as now practiced. They determine almost entirely the mechanical 
 properties of the arc-fused metal. The observed elongation of 
 the specimen under tension is due to the combined action of 
 
 191 
 
192 ELECTRIC WELDING 
 
 the numerous unsound spots rather than to the ductility of 
 the metal. That the metal is inherently ductile, however, will 
 be shown by the changes in the microstructure, produced by 
 cold-bending. By taking extreme precautions during the 
 fusion, a great deal of the unsoundness may be avoided and 
 the mechanical properties of the metal be considerably im- 
 proved. The specimens described, however, are more repre- 
 sentative of actual present practice in welding. 
 
 General Features of Microstructure. For purposes of com- 
 parison the microstructure of the electrodes before fusion is 
 shown in (1) and (2), Fig. 157. The "A" electrodes have 
 the appearance of steel of a very low carbon content ; in some 
 cases they were in the cold-rolled state ; all showed a consider- 
 able number of inclusions. The "B" electrodes have the struc- 
 ture of a mild steel and are much freer from inclusions than 
 are those of the other type. It is, undoubtedly true, however, 
 that the condition of the arc-fused metal with respect to the 
 number of inclusions is a result of the fusion rather than of 
 the initial state of the metal. 
 
 It is to be expected that the microstructure of the material 
 after fusion will be very considerably changed, since the metal 
 is then essentially the same as a casting. It has some features, 
 however, which are not to be found in steel as ordinarily cast. 
 The general type of microstructure was found to vary in the 
 different specimens and to range from a condition which will 
 be designated as "columnar" to that of a uniform fine equi- 
 axed crystalline arrangement as shown at 3 and 4, Fig. 157A. 
 This observation held true for both types of electrodes, whether 
 bare or covered. In the examination of cross-sections of the 
 blocks of arc-fused metal, it was noticed that the equi-axed 
 type of structure is prevalent throughout the interior of the 
 piece and the columnar is to be found generally nearer the 
 surface i.e., in the metal deposited last. It may be inferred 
 from this that the metal of the layers which were deposited 
 during the' early part of the preparation of the specimen is 
 refined considerably by the successive heatings to which it is 
 subjected as additional layers of metal are deposited. The 
 general type of structure of the tension bars cut from the 
 blocks of arc fused metal will vary considerably according 
 to the amount of refining which has taken place as well as 
 
METALLOGRAPHY OF ARC-FUSED STEEL 
 
 193 
 
 the relative position of the tension specimen within the block. 
 In addition it was noticed that the columnar and coarse equi- 
 axed crystalline condition appears to predominate with fusion 
 at high-current densities. 
 
 FIG. 157. (1) "A" Electrode, 5 / 32 -in. Diameter. Annealed As Received. 
 (2) "B" Electrode, 3 /i 6 -in. Diameter. Cold-Drawn. 
 Picric Acid Etching. 
 
 3 
 
 FIG. 15 7 A. (3) Columnar Structure of B 2 . X 66 - Five Per Cent Picric 
 Acid Etching. (4) Equi-axed Structure of AD 3 . X 200 - Two P er 
 Cent Alcoholic HN0 3 Etching. 
 
 Microscopic Evidence of Unsoundness. In all of the speci- 
 mens of arc-fused metal examined microscopically there ap- 
 pear to be numerous tiny globules of oxide as shown in Figs. 
 158 to 160. A magnification of 500 diameters is usually neces- 
 sary to show these inclusions. In general they appear to have 
 
194 
 
 ELECTRIC WELDING 
 
 Is 
 
 !2 
 
 'o 
 <& 
 
 f 
 
 t^ 
 
 W -2 
 
 HH M x-v e 
 
 d 
 
 O) 
 
 t 
 
 02 
 
 ct 
 
 
METALLOGRAPHY OF ARC-FUSED STEEL 195 
 
 no definite arrangement, but occur indiscriminately through- 
 out the crystals of iron. 
 
 A type of unsoundness frequently found is that shown in 
 (5), (6) and (7), Fig. 158; this will be referred to as "metallic- 
 globule inclusions." In general these globules possess a 
 microstructure similar to that of the surrounding metal, but 
 are enveloped by a film, presumably of oxide. It seems prob- 
 able that they are small metallic particles which were formed 
 as a sort of spray at the tip of the electrode and which were 
 deposited on the solidified crust surrounding the pool of molten 
 metal directly under the arc. These solidified particles ap- 
 parently are not fused in with the metal which is subsequently 
 deposited over them i.e., during the formation of this same 
 layer and before any brushing of the surface occurs. By taking 
 extreme precautions during the fusion, a great deal of this 
 unsoundness may be avoided and the mechanical properties of 
 the metal may be considerably improved. 
 
 Characteristic "Needles" or "Plates." The most char- 
 acteristic feature of the steel after fusion is the presence of 
 numerous lines or needles within the crysals. The general 
 appearance of this feature of the structure is shown in (8) 
 to (11), Fig. 159, inclusive. The number and the distribution 
 of these needles were found to vary greatly in the different 
 specimens. In general, they are most abundant in the columnar 
 and in the coarse equi-axed crystals ; the finer equi-axed crystals 
 in some specimens were found to be quite free from them, 
 although exceptions were found to this rule. In general, a 
 needle lies entirely within the bounds of an individual crystal. 
 Some instances were found, however, where a needle appeared 
 to lie across the boundary and so lie within two adjacent 
 crystals. Several instances of this tendency have been noted 
 in the literature on this subject. The needles have an ap- 
 preciable width, and when the specimen is etched with 2 per 
 cent alcoholic nitric acid they appear much the same as 
 cementite i.e., they remain uncolored, although they may 
 appear to widen and. darken if the etching is prolonged con- 
 siderably. The apparent widening is evidently due to the 
 attack of the adjacent ferrite along the boundary line between 
 the two. The tendency of the lines to darken when etched 
 with a hot alkaline solution of sodium picrate, as reported 
 
196 
 
 ELECTRIC WELD1NU 
 
 
 FIG. 159 (8 to 11). Characteristic "Needles" or "Plates" X 375. 
 
 (8) BDg etched with 5 per cent picric acid in alcohol. 
 
 (9) Specimen BD 8 after using for thermal analysis, re-heated in vacuo to 900 
 deg. C. four times. Picric acid etching. 
 
 (10) Same as (9) except etched in hot alkaline sodium picrate solution. 
 
 (11) Specimen of welded joint between slip-plate. Additional very small needles 
 are noted. Etching: 2 per cent HNOs in alcohol. 
 
METALLOGRAPHY OF ARC-FUSED STEEL 197 
 
 by Comstock, was confirmed; (10) illustrates the appearance 
 when etched in this manner. The needles are sometimes found 
 in a rectangular grouping i.e., they form angles of 90 deg. 
 with one another. In other cases they appear to be arranged 
 along the octahedral planes of the crystal i.e., at 60 deg. to 
 one another. This is best seen in specimens which have been 
 heated, as explained below : 
 
 In some of the specimens certain crystals showed groups 
 of very fine short needles as in (11). The needles comprising 
 any one group or family are usually arranged parallel to one 
 another, but the various groups are often arranged definitely 
 with respect to one another in the same manner as described 
 above. Similar needles have been reported in articles by 
 S. W. Miller. 
 
 An attempt was made by Dr. P. D. Merica to determine 
 whether the so-called lines or needles were really of the shape 
 of needles or of tiny plates or scales. An area was carefully 
 located on a specimen prepared for microscopic examination, 
 which was then ground down slightly and repolished several 
 times. It was possible to measure the amount of metal removed 
 during the slight grinding by observing the gradual disap- 
 pearance of certain of the spherical oxide inclusions the 
 diameter of which could be accurately measured. By slightly 
 etching the specimen after polishing anew it was possible to 
 follow the gradual disappearance of some of the most prominent 
 needles and to measure the maximum " depth" of such needles. 
 It was concluded from the series of examinations that the term 
 "plate" is more correctly descriptive of this feature of the 
 structure than "line" or "needle." The thickness of the plate 
 i.e., the width of the needle varies from 0.0005 to 0.001 
 mm. and the width of the plate ("depth") may be as great 
 as 0.005 mm. The persistence of the plates after a regrinding 
 of the surface used for microscopical examination may be noted 
 in some of the micrographs given by Miller. The authors are 
 not aware, however, of any other attempt to determine the 
 shape of these plates by actual measurements of their 
 dimensions. 
 
 Plates Probably Due to Nitrates. The usual explanation 
 of the nature of these plates is that they are due to the nitrogen 
 which is taken up by the iron during its fusion. Other sug- 
 
198 ELECTRIC WELDING 
 
 gestions which have been offered previously attribute them to 
 oxide of iron and to carbide. The suggestion concerning oxide 
 may be dismissed with a few words. The plates are distinctly 
 different from oxide in their form and their behavior upon 
 heating. It is shown later that the tiny oxide globules coalesce 
 into larger ones upon prolonged heating in vacuo; the plates 
 also increase in size and become much more distinct (see (32), 
 (34) and (36), Fig. 166). In no case, however, was any inter- 
 mediate stage between the globular form and the plate pro- 
 
 FiG. 160. (12) Specimen AD 3 , Etched with 2 Per Cent Alcooholic Nitric 
 Acid. Shows Pearlite Islands, " Needles" and Oxide Inclusions. 
 X 750. 
 
 duced such as would be expected if both were of the same 
 chemical nature. 
 
 Regarding the assumption that they are cementite plates, 
 it may be said that the tendency during fusion is for the carbon 
 to be "burned out," thus leaving an iron of low carbon content. 
 In all the specimens, islands of pearlite (usually with cementite 
 borders) are to be found and may easily be distinguished with 
 certainty. The number of such islands in any specimen appears 
 to be sufficient to account for the carbon content of the 
 material as revealed by chemical analysis. In some cases the 
 peariite islands are associated with a certain type of " lines " 
 
METALLOGRAPHY OF ARC-FUSED STEEL 199 
 
 or "needles" such as are shown in (12), Fig. 160. These 
 needles, however, appear distinctly different from those of the 
 prevailing type and are usually easily distinguished from them. 
 The fact that the plates found in the arc-fused metal are 
 identical in appearance and in behavior (e.g., etching) as 
 those found in iron which has been nitrogenized is strong 
 evidence that both are of the same nature. (13) Fig. 161 
 shows the appearance of the plates produced in electrolytic 
 iron by heating it for some time in pure ammonia gas. These 
 plates behave in the same characteristic manner when etched 
 with hot sodium picrate as do those occurring in arc-fused 
 
 13. mr 14 
 
 FIG. 161. (13) Characteristic Structure of Electrolytic Iron Heated in 
 
 KH 3 at 650 Deg. C. Two Types of Nitride Plates. Etched with 2 
 
 Per Cent Alcoholic HNO 3 . X 375 - 
 FIG. 161. (14) Arc-Fused Iron Produced in CO 2 Atmosphere. Type "A," 
 
 Ysa-in. Electrodes, 150 Amperes. Etched with 5 Per Cent Picric Acid 
 
 in Alcohol. X 375 - 
 
 iron i.e., they darken slightly and appear as finest rulings 
 across the bright ferrite. The fact that the nitrogen content 
 of the steel as shown by chemical analysis is increased by the 
 arc-fusion also supports the view that the change which occurs 
 in the structure is due to the nitrogen. The statement has 
 been made by Ruder that metal fused in the absence of nitrogen 
 i.e., in an atmosphere of carbon dioxide or of hydrogen 
 does not contain any plates and hence the view that the plates 
 are due to the nitrogen is very much strengthened. In (15), 
 Fig. 162, the appearance of specimens prepared at the Bureau 
 by arc fusion of electrodes of type "A" in an atmosphere of 
 
200 
 
 ELECTRIC WELDING 
 
METALLOGRAPHY OF ARC-FUSED STEEL 201 
 
 carbon dioxide is shown. The microscopic examination of the 
 fused metal shows unmistakable evidence of the presence of 
 some plates, although they differ somewhat from those found 
 in nitrogenized iron and in metal fused in the air by the 
 electric arc. Evidently they are due to a different cause from 
 the majority of those formed in the iron fused in air. For 
 convenience, in the remainder of the discussion the "plates" 
 will be referred to as "nitride plates." 
 
 Relation of Microstructure to the Path of Rupture. The 
 faces of the fracture of several of the tension specimens after 
 testing were heavily plated electrolytically with copper so as 
 to preserve the edges of the specimens during the polishing 
 of the section and examined microscopically to see if the course 
 of the path of rupture had been influenced to an appreciable 
 extent by the microstructural features. In general, the frac- 
 ture appears to be intcrerystallme in type. Along the path 
 of rupture in all of the specimens were smooth-edged hollows, 
 many of which had evidently been occupied by the "metallic 
 globules" referred to above, while others were gas-holes or 
 pores. Portions of the fracture were intracrystalline and 
 presented a jagged outline, but it cannot be stated with cer- 
 tainty whether the needles have influenced the break at such 
 points or not. (16) shows the appearance of some of the 
 fractures and illustrates that, in general, the "nitride plates" 
 do not appear to determine to any appreciable extent the course 
 of the path of rupture. 
 
 The behavior of the plates under deformation can best 
 be seen in thin specimens of the metal which were bent through 
 a considerable angle. Results of examination of welds treated 
 in this manner have been described by Miller. Small rec- 
 tangular plates of the arc-fused metal, approximately 3 / 32 in. 
 thick, were polished and etched for microscopic examination 
 and were then bent in the vise through an angle of 20 deg. 
 (approximate). 
 
 In (18) to (21), Fig. 163, inclusive are given micrographs 
 illustrating the characteristic behavior of the material when 
 subjected to bending. For moderate distortion the nitride 
 plates influence the course of the slip-bands in much the same 
 way that grain boundaries do i.e., the slip-bands terminate 
 usually on meeting one of the plates with a change of direction 
 
202 
 
 ELECTRIC WELDING 
 
 so that they form a sharper angle with the plate than does 
 the portion of the slip-band which is at some distance away 
 (18). When the deformation is greater the slip-bands occur 
 on both sides of the nitride plate, but usually show a slight 
 variation in direction on the two sides of the nitride plate 
 (19) ; this is often quite pronounced at the point where the 
 plate is crossed by the slip-band. In a few cases evidence 
 
 a 
 
 19 
 
 2O 
 
 FIG. 163. (18 to 21) Behavior of " Nitride Plates" During Plastic De- 
 formation of the Iron. Specimen RD 2 , Etched with 2 Per Cent 
 Alcoholic, Nitric Acid Before Bending. X 500. 
 
 of the "faulting" of the plate as a result of severe distortion 
 was noted (20). This was a rare appearance, however, because 
 of the nature of the metal, and is not shown in (21).. On 
 account of the inclusions and other features of unsoundness 
 of the metal, rupture occurs at such points before the sound 
 crystals have been sufficiently strained to shoAv the character- 
 istic behavior of the plates. Other micrographs show the 
 beginning of a fracture around one of the "metallic globule" 
 
METALLOGRAPHY OF ARC-FUSED STEEL 203 
 
 inclusions before the surrounding metal lias been very severely 
 strained. For this reason the influence of the plates on the 
 mechanical properties of the crystals cannot be stated with 
 certainty. It would appear, however, that on account of the 
 apparently unavoidable unsoundness of the metal, any possible 
 influence of the nitride plates upon the mechanical properties 
 of the material is quite negligible. 
 
 Some of the same specimens used for cold bending were 
 torn partially in two after localizing the tear by means of a 
 saw cut in the edge of the plate. The specimen was then 
 copper plated and prepared for microscopic examination, the 
 surface having been ground away sufficiently to reveal the 
 weld-metal with the tear in it. The nitride plates did not 
 appear to have determined to any extent the path taken in 
 the rupture produced in this manner. 
 
 Effect of Heat Treatment Upon Structure. With the view 
 of possibly gaming further information as to the nature of 
 the plates (assumed to be nitride), which constitute such a 
 characteristic feature of the microstructure, a series of heat 
 treatments were carried out upon several specimens of 
 arc-fused electrodes of both types. Briefly stated, the 
 treatment consisted in quenching the specimens in cold 
 water after heating them for a period of ten or fifteen minutes 
 at a temperature considerable above that of the Ac 3 transforma- 
 tion; 925, 950 and 1,000 dcg. C. were the temperatures used. 
 After microscopical examination of the different quenched 
 specimens they were tempered at different temperatures which 
 varied from 600 to 925 deg. C. for periods of ten and twenty 
 minutes. The samples which were used were rather small in 
 size, being only -J in. thick, in order that the effect of the 
 treatment should be very thorough, were taken from test bars 
 A 2 , A 3 , AD 10 , B 2 , B 6 and B 9 . These represented metal which 
 had been deposited under different conditions of current den- 
 sity, as shown in Table X. No plates were found to be present 
 in any of the specimens after quenching. (22) Fig. 164 shows 
 the appearance of one of the quenched bars, a condition which 
 is typical of all. The structure indicates that the material 
 comprising the plates had dissolved in the matrix of iron and 
 had been retained in this condition upon quenching. The 
 needle-like striations within the individual grains are char- 
 
204 
 
 ELECTRIC WELDING 
 
METALLOGRAPHY OF ARC-FUSED STEEL 205 
 
 acteristic of the condition resulting from the severe quenching 
 and are to be observed at times in steel of a very low carbon 
 content. (23) shows the appearance of one of the "A" elec- 
 trodes (V 32 i n -) quenched in cold water from 1,000 deg. C. 
 Some of the crystals of the quenched iron also show interior 
 markings somewhat similar in appearance to the nitride plates 
 (24). These are, however, probably of the same nature as 
 the interior tree-like network sometimes seen in ferrite whicli 
 has been heated to a high temperature. The striations were 
 found to be most pronounced in the specimens of arc-fused 
 metal which were quenched from the highest temperatures, 
 as might be expected. Braune states that nitride of iron in 
 quenched metal is retained in solution in the martensite. The 
 same may be inferred from the statement by Giesen that "in 
 hardened steel, it (nitrogen) occurs in martensite." Ruder 
 has also shown that nitrogenized electrolytic iron (3 hr. at 700 
 deg. C. in ammonia) after being quenched in water from tem- 
 peratures 600 to 950 deg. C. shows none of the plates which 
 were present before the specimen was heated. 
 
 The sets of specimens (A 2 , A 6 , AD 10 , B 2 , B 6 and B ) 
 quenched from above the temperature of the Ac 3 transforma- 
 tion were heated to various temperatures, 600, 700, 800 and 
 925 deg. C. In all cases the specimens were maintained at 
 the maximum temperature for approximately ten to fifteen 
 minutes and then cooled in the furnace. (25) to (30), Fig. 165, 
 inclusive summarize the resulting effects upon the structure. 
 Heating to 650 deg. C. is not sufficient to allow the plates 
 to redevelop, but in the specimens heated to 700 deg. C. a few 
 small ones were found. The effect is progressively more pro- 
 nounced with the increased temperature of tempering, and in 
 the material heated to 925 deg. C. they are as large and as 
 numerous as in any of the arc-fused specimens. The heating 
 also develops the islands of pearlite which are not always to 
 be distinguished very clearly in the simple fused metal. The 
 work of Ruder shows that nitrogenized iron which has been 
 quenched and so rendered free from the nitride plates behaves 
 in a similar manner upon heating to temperatures varying 
 from 700 to 950 deg. C. ; the plates reappear after a heating 
 for fifteen minutes at 700 deg. C. (or above), followed by a 
 slow cooling. The similarity in behavior of the two is a 
 
206 
 
 ELECTRIC WELD1JMG 
 
 FlG. 165. (25 to 30) Effect of Heat-Treatment of Arc-Fused Iron. 
 All etched with 2 per cent alcoholic HNOs. X 450. 
 
 (25) Specimen ADio as deposited. 
 
 (26) Same after quenching from above HCa and reheating to 650 deg. C. No 
 "plates" have formed. 
 
 (27) Specimen ADio after quenching from above HCs and reheating to 700 
 deg. C. "Plates beginning to reform. 
 
 (28) Specimen 69 after quenching from above ACs and reheating to 800 dep. C. 
 
 (29) Specimen B2 after quenching from above ACa and reheating to 925 dep. C. 
 
 (30) Specimen Au after quenching from above ACa and reheating to 925 deg. C. 
 
METALLOGRAPHY OF ARC-FUSED STEEL 207 
 
 FIG. 1G6. (31 to 36) Effect of 6-hr. Heating at 1000 Deg. C. in Vacuo. 
 
 All etched with 2 per cent alcoholic HNO 3 . X 450. 
 
 (31) Initial structure of AD2. 
 
 (32) ADs after heating. 
 
 (33) Initial structure of B*. 
 
 (34) B 4 after heating. 
 
 (35) Initial structure of Aio. 
 
 (36) Aio after heating. 
 
208 
 
 ELECTRIC WELDING 
 
 further line of evidence that the arc-fused metal contains more 
 or less nitrogenizcd iron throughout its mass. 
 
 Plates Remain After Long Annealing. The persistence of 
 the nitride plates was also studied in specimens heated at 
 1,000 deg. C. in vacuo for a period of 6 hr. A set of specimens 
 (one each of test-bars AD 2 , A 3 , AD 6 , A 10 , B 2 , B 4 , B., and BD 5 ) 
 was packed in a Usalite crucible, and covered with alundum 
 "sand" ; this crucible was surrounded by a protecting alundum 
 tube and the whole heated in an Arsem furnace. A vacuum, 
 
 PIG. 167. (37) Effect of Pronounced Heating Upon the Structure of 
 
 Arc-Fused Iron. 
 
 Specimen ADio was heated for 6 hr. in vacuo at 1000 deg. C. The micrograph 
 represents a section of the specimen at one corner. The oxide and "nitride plates" 
 have been removed in the exposed tip of the thread. Etching, 2 per cent alcoholic 
 solution of nitric acid. X 150. 
 
 equivalent to 0.2 mm. mercury, was maintained for the greater 
 part of the 6-hr, heating period; for the remainder of the 
 time the vacuum was equivalent to 0.1 to 0.2 mm. mercury. 
 The specimens were allowed to cool in the furnace. Ruder 
 has stated that 1 hr., heating in vacuo at 1,000 deg. C. was 
 sufficient to cause a marked diminution in the number of plates 
 in both arc-wefd material and nitrogenized iron and that at 
 1,200 deg. C. they disappeared entirely. 
 
 The results obtained are shown in (31) to (36), Fig. 166, 
 
METALLOGRAPHY OF ARC-FUSED STEEL 209 
 
 inclusive. In contradistinction to Ruder 's work the plates arc 
 more conspicuous and larger than before, the oxide specks 
 are larger and fewer in number. Many of the " plates" appear 
 to have been influenced in their position by an oxide globule. 
 It would appear that the conditions of the experiment are 
 favorable for a migration of the oxide through an appreciable 
 distance and for a coalescing into larger masses. (32), (34) 
 and (36) all show some cementite at the grain boundaries 
 which resulted from the "divorcing" of pearlite. The oxide 
 is eliminated entirely in a surface layer averaging approx- 
 imately 0.15 mm. in depth. Only in projections (right-angled 
 corners, sections of threads of the tension bar, etc.), was there 
 any removal of the nitride plates by the action of the continued 
 heating in vacuo. This is shown in (37), Fig. 167, which illus- 
 trates the removal of the oxide inclusions also. No evidence 
 was found that the small amount of carbon present in the 
 arc-fused metal is eliminated, particularly beneath the surface. 
 
 (6) Fig. 158 illustrates an interesting exception to the rule 
 that the nitride plates are flat. In the metallic and globular 
 inclusion shown the plates have a very pronounced curve. The 
 general appearance suggests that the " metallic globules" solid- 
 ified under a condition of "constraint" and that this condi- 
 tion still persists even after the 6-hr, heating at 1,000 deg. C. 
 which the specimen received. 
 
 Several of the specimens which were heated in vacua (6 hr. 
 at 1,000 deg. C.) were analyzed for nitrogen. The results are 
 given in Table XVI. 
 
 TABLE XVI. CHANGE IN NITROGEN CONTENT UPON HEATING 
 
 
 
 Average 
 
 Nitrogen Content, 
 
 
 
 Wt. of 
 
 
 per Cent 
 
 
 
 Sample 
 
 Before 
 
 After Heating 
 
 Loss 
 
 Specimen 
 
 in Gr. 
 
 Heating 
 
 in Vacuo. 
 
 per Cent 
 
 A 3 
 
 1.39 
 
 0.127 
 
 0.062 
 
 51 
 
 B 4 
 
 60 
 
 124 
 
 078 
 
 37 
 
 BD 5 
 
 1.62 
 
 0.140 
 
 0059 
 
 57 
 
 B 5 . 
 
 1 16 
 
 121 
 
 054 
 
 55 
 
 
 
 
 
 
 The fact that the specimens lose nitrogen upon heating 
 (although the amount remaining is still many times the 
 nitrogen-content of the metal before fusion), coupled with 
 the fact that the " nitride plates" are larger and more con- 
 
210 ELECTRIC WELDING 
 
 spicuous after heating than before, suggests very strongly 
 that these plates are not simple nitride of iron. The method 
 used for the determination of nitrogen gives only the "nitride" 
 nitrogen, hence a possible explanation for the change in 
 nitrogen content is that it has been converted into another 
 form than nitride and may not have been eliminated from 
 the specimen. 
 
 Thermal Analysis of Arc-Fused Steel. In order to throw 
 further light on the nature of the plates j( nitride) found in 
 the metal after fusion in the arc, the thermal characteristics 
 of the electrode material before and after fusion as revealed 
 by heating and cooling curves were determined. Samples of 
 a 3 / 16 -in. electrode of type "A" and of the specimen A, which 
 resulted from the fusion were used as material (composition 
 in Tables IX and XII.) 
 
 TABLE XVII. THE THERMAL CHARACTERISTICS OF ARC-FUSED IRON 
 
 H 
 
 C 
 
 1 
 
 1 
 
 I 
 
 I 
 
 So 
 
 Ao2, Maximum 
 Deg. C. 
 
 Beginning 
 Maximum, Deg. C. " 
 
 1 
 
 Maximum Temp., 
 Deg. C. 
 
 Time Above As,- 
 Min. 
 
 Beginning 
 
 1 
 Maximum. Deg. C. ' 
 
 Co 
 
 1 
 
 1 
 
 Maximum, Deg. C. ^ 
 
 Unfused Electrode 
 
 
 
 15* 
 
 768 
 
 892 910 
 
 918 
 
 960 
 
 
 896 
 
 893 
 
 879 
 
 766 
 
 
 
 765 
 
 897 911 
 
 916 
 
 960 
 
 
 895 
 
 891 
 
 879 
 
 766 
 
 Arc-Fused 
 
 Metal t 
 
 
 
 
 
 0. 
 
 14 
 
 764 
 
 .... 847 
 
 874 
 
 960 
 
 28 
 
 847 
 
 838 
 
 820 
 
 764 
 
 
 
 13 
 
 764 
 
 849 
 
 876 
 
 985 
 
 42 
 
 847 
 
 836 
 
 822 
 
 764 
 
 
 
 13 
 
 764 
 
 . . 844 
 
 870 
 
 960 
 
 29 
 
 847 
 
 837 
 
 821 
 
 765 
 
 
 
 13 
 
 766 
 
 850 
 
 874 
 
 1.035 
 
 256 
 
 848 
 
 835 
 
 816 
 
 764 
 
 * Heated at rate of 16 dcg. C. per sec., cooled 0.15 deg. C. per sec. for other 
 specimens, the rate of cooling equaled the rate of heating. 
 
 t The same specimen was heated four times in succession, as shown. (Fig 38) 
 
 In Fig. 168 are given the curves obtained which show the 
 characteristic behavior of the arc-fused metal upon heating. 
 The commonly used inverse-rate method was employed in plot- 
 ting the data ; the details of manipulation and the precautions 
 necessary for the thermal analysis have already been described. 
 In Table XVII are summarized the data shown graphically in 
 the last cut. 
 
 The principal change to be noted which has resulted from 
 
METALLOGRAPHY OF ARC-FUSED STEEL 
 
 211 
 
 O 
 
 J I 
 
 tS 
 
 M/ 
 
 I - 
 
 s- 
 
 EH * 
 
 o J> 
 
 ?l 
 
 ^ E 
 
 m S 
 
 ? 
 
212 ELECTRIC WELDING 
 
 the arc-fusion of the iron is in the A 3 transformation. This 
 is now very similar to the corresponding change observed in 
 a very mild steel (e.g., approximately 0.15 per cent carbon). 
 That the difference in the A 3 transformation of the arc-fused 
 metal as compared with that of the original electrode is not 
 due to an increase in the carbon content is evident from the 
 lack of the sharp inflection of the A a transformation ("pear lite 
 point ") which would, of necessity, be found in a low carbon 
 steel. No evidence of the A x change was observed for the 
 arc-fused iron within the range of temperature, 150 to 950 
 deg C. The change in the character of the A 3 transformation 
 is without doubt to be attributed to the influence of the 
 increased nitrogen-content of the iron. 
 
 The specimen was maintained above the temperature of 
 the A 3 transformation for a total period (four heatings) of 
 6 hr., the maximum temperature being 1,035 deg. C. The 
 transformation apparently is unaffected by the long-continued 
 heating, thus confirming the results described in the preceding 
 section. 
 
 In discussing the properties of steel nitrogenized by melting 
 it in nitrogen under pressure, Andrews states that it was 
 found possible to extract almost entirely the small quantities 
 of nitrogen by heating a specimen at 1,000 deg. C. in vacuo 
 for periods of 1 to 6 hr. The metal used contained 0.16 per 
 cent carbon and 0.3 per cent nitrogen. Thermal curves are 
 given to show that there are no critical transformations in 
 the material; the nitrogen suppresses them. They gradually 
 reappear, however, as the nitrogen is removed by heating the 
 material in vacuo at 1,000 deg. C. Several days' heating was 
 required, however, to obtain an entirely degasified product, 
 the carbon being removed also. A further statement is made 
 that a steel of 0.6 per cent carbon content containing 0.25 per 
 cent nitrogen can be brought back to the normal state of a 
 pure steel only by several weeks' heating in vacuo. 
 
 The results of the thermal analysis add considerable con- 
 firmatory evidence to support the view that the plates existing 
 in the arc-fused metal are due to the nitrogen rather than 
 to carbon. 
 
 Summary. Microscopic examination of bent pieces of arc- 
 fused metal show that the metallic grains are inherently ductile, 
 
METALLOGRAPHY OF ARC-FUSED STEEL 213 
 
 even to a high degree. Grosser imperfections, however, are 
 entirely sufficient to mask this excellence. 
 
 The view that the characteristic features observed in the 
 structure of the arc-fused iron are due to the increased nitrogen 
 content is supported by several different lines of evidence. 
 These include the likeness of the structure of the material 
 to that of pure iron which has been "nitrogenized," the 
 similarity in the behavior of both arc-fused and nitrogenized 
 iron upon heating, the evidence shown by thermal analysis 
 of the arc-fused metal, together with the fact that, as shown 
 by chemical analysis, the nitrogen content , increases during 
 fusion, while the other elements, aside from oxygen, decrease 
 in amount. The characteristic form in which oxide occurs in 
 iron, together with its behavior upon heating, renders the 
 assumption that the oxide is responsible for the plates observed 
 in the material a very improbable one. 
 
 Judged from the results obtained, neither type of electrode 
 appears to have a marked advantage over the other. The use 
 of a slight protective coating on the electrodes does not appear 
 to affect the mechanical properties of the arc-fused metal 
 materially in any way. The specimens were prepared in a 
 manner quite different from that used ordinarily in electric-arc 
 welding and the results do not justify any specific recom- 
 mendations concerning methods of practice in welding. 
 
CHAPTER XI 
 AUTOMATIC ARC WELDING 
 
 The automatic arc welding machine, made by the General 
 Electric Co., Schenectady, N. Y., is a device for automatically 
 feeding metallic electrode wire into the welding arc at the 
 rate required to hold a constant arc length, says H. L. Unland 
 in a paper read before the American Welding Society. Under 
 these circumstances the electrical conditions are kept constant 
 and the resulting weld is uniform and its quality is thereby 
 improved. It is possible with this device to weld at a speed 
 of from two to six times the rate attained by skilled operators 
 welding by hand. This is partly due to the stability of the 
 welding conditions and partly due to the fact that the elec- 
 trode is fed from a continuous reel, thus eliminating the chang- 
 ing of electrodes. The automatic welding machine is adaptable 
 to practically any form of weld from butt welding of plates 
 to the depositing of metal on worn surfaces such as shafts, 
 wheels, etc. 
 
 Everyone who has made any investigation of electric arc 
 welding has noted the wide variation in results obtained by 
 different welders operating, as nearly as can be determined, 
 under identical conditions. This also applies to the operations 
 of a single welder at different times under identical conditions. 
 These variations affect practically all factors of welding such 
 as speed of welding, amount of electrode consumed, etc. When 
 indicating instruments are connected to an electric welding 
 circuit, continual variations of considerable magnitude in the 
 current and voltage of the arc are at once noticed. Consider- 
 able variation was found some years ago in the cutting of 
 steel plates by the gas process and when an equipment was 
 devised to mechanically travel the cutting torch over the plate 
 a series of tests to determine the maximum economical speed, 
 gas pressure, etc., for the various thickness of plate were made. 
 
 214 
 
AUTOMATIC ARC WELDING 215 
 
 The result was that the speed of cutting was increased to as 
 much as four or five times the rate possible when operating 
 under the unsteady conditions incident to hand manipulation 
 of the torch. Further, the gas consumption for a given cut 
 was found to be decreased very greatly. 
 
 As a result of many experiences an investigation was started 
 to determine what could be done in controlling the feed of 
 the electrode to the electric arc in a metallic electrode welding 
 circuit. An electric arc is inherently unstable, the fluctuations 
 taking place with extreme rapidity. In any regulating device 
 the sensitiveness depends on the percentage of variation from 
 normal rather than on the actual magnitude of the values, since 
 these are always reduced to approximately a common factor 
 by the use of shunts, current transformers, or series resist- 
 ances. The characteristics of practically all electric welding 
 circuits are such that the current and voltage are inter-related, 
 an increase in one causing a corresponding decrease in the 
 other. Where this is the case it will generally be found that 
 the percentage variation of the voltage from normal when 
 taken at the customary arc voltage of 20, will be approximately 
 twice the percentage variation in current. Further, an increase 
 in arc voltage, other conditions remaining the same, indicates 
 that the arc has been lengthened, thus giving the metal a 
 greater opportunity to oxidize in the arc with a probability 
 of reduction in quality of the weld. The automatic arc weld- 
 ing machine utilizes the arc voltage as the basis for regulating 
 the equipment. The rate of feeding the wire varies over a wide 
 range, due to the use of electrodes of different diameters, 
 the use of different current values, etc., caused by details of the 
 particular weld to be made. The simplest and most reliable 
 method of electrically obtaining variations in speed is by 
 means of a separately excited direct current motor. Thus the 
 operation of this equipment is limited to direct current arc 
 welding circuits, but these may be of any established type, 
 the variations in characteristics of the welding circuits being 
 taken care of by proper selection of resistors, coils, etc., in 
 the control. 
 
 The Welding Head. The welding head consists essentially 
 of a set of rollers for gripping the wire and feeding it to 
 the arc. These rollers are suitably connected through gearing 
 
216 ELECTRIC WELDING 
 
 to a small direct-current motor, the armature of which is con- 
 nected across the terminals of the welding arc. This connec- 
 tion causes the motor to increase in speed as the voltage across 
 the arc increases due to an increase in the length of the arc 
 and to decrease in speed as the voltage decreases, due to a 
 shortened arc. A small relay operating on the principle of 
 a generator voltage regulator is connected in the field circuit 
 of the motor which assists in the speed control of the motor 
 as the arc voltage varies. Rheostats, for regulating and adjust- 
 ing the are voltage, are provided by means of which the 
 equipment can be made to maintain steadily an arc of the 
 desired length and this value may be varied from over twenty 
 to as low as nine volts. No provision is made in the machine 
 for adjustment of the welding current since the automatic 
 operation is in no way dependent on it. The welding current 
 adjustment is taken care of by the control panel of the welding 
 set. This may be either of the variable voltage or constant 
 potential type but it is necessary to have a source of constant 
 potential to excite the fields of feed motor. It may be possible 
 to obtain this excitation from the welding circuit, but this 
 is not essential. The voltage of both the welding and constant 
 potential circuits is immaterial, provided it is not too high, 
 but these voltages must be known before the proper rheostats 
 can be supplied. 
 
 On account of the great variation in conditions under which 
 this welding equipment may be used it is provided with a 
 base which may be bolted to any form of support. It may be 
 held stationary and the work traveled past the arc or welding 
 head may be movable and the work held stationary. These 
 points will be dictated by the relative size of the work and 
 the head and the equipment which may be available. Provision 
 must be made for traveling one or the other at a uniform 
 speed in order to carry the arc along the weld. In the case 
 of straight seams a lathe or planer bed may be utilized for 
 this purpose and for circular seams a lathe or boring mill 
 may be used. In many cases it will be found desirable to 
 use clamping jigs for securely holding the work in shape and 
 also to facilitate placing in position and removing from the 
 feeding mechanism. 
 
 In Fig. 169, the welding head is shown mounted on a special 
 
AUTOMATIC ARC WELDING 
 
 217 
 
 device for making circular welds. The work table is driven 
 through a worm and worm gear by means of a separate motor. 
 
 FIG. 169. Special Set-Up of Machine for Circular Welding. 
 
 The welding head may be led along the arm by means of 
 the handwheel, and it may be tilted at an angle of 45 deg. 
 
218 
 
 ELECTRIC WELDING 
 
 both at right angles to the line of weld and also parallel 
 to the line of weld. Fig. 170 shows the building up of a shaft, 
 the work being mounted on lathe centers and the welding 
 head placed on a bracket clamped to saddle. 
 
 Fig. 171 shows a simplified diagram of the control of the 
 feed motor. In this cut A is the regulating rheostat in the 
 motor field circuit controlled by the arc voltage regulator G; 
 B is the adjusting rheostat in the motor field circuit j F 
 
 FIG. 170. Set-Up for Building up a Shaft. 
 
 indicates the feed motor field winding; M the feed motor wind- 
 ing; D is the resistance in the motor armature circuit to adjust 
 the speed when starting the feed motor before the arc is struck. 
 The open-circuit voltage of the welding circuit is ordinarily 
 considerably higher than the arc voltage. This resistance D 
 is short circuited by contactor X when the arc is struck. The 
 arc voltage regulator G maintains constant arc voltage by 
 varying the motor field strength through resistor A. The 
 regulator is adjusted to hold the desired voltage by the rheostat 
 
AUTOMATIC ARC WELDING 
 
 219 
 
 C. Permanent resistance E is in series with the over-voltage 
 relay H, to compensate for the voltage of the welding circuit. 
 Over voltage relay H holds open the coil circuit of the regulator 
 G until the electrode makes contact in order to protect the 
 coil from burning out. 
 
 Observation of indicating meters on the control panel show 
 that the current and voltage are practically constant, but it 
 should be remembered that all indicating meters have a certain 
 amount of damping which prevents observation of the varia- 
 tions which are extremely rapid or of small magnitude. The 
 resultant value as read on the instrument is the average value. 
 Oscillographs taken with short arcs show that notwithstanding 
 the fact that the indicating meters show a constant value, a 
 
 Ammeter 
 
 FIG. 171. Simplified Diagram of Control of Feed Motor. 
 
 succession of rapid short circuits is continually taking place, 
 apparently due to particles of the molten wire practically short- 
 circuiting the arc in passing from the electrode to the work. 
 This is indicated by the fact that the voltage curve fell to 
 zero each time, and accompanying each such fluctuation there 
 was an increase in the current. It was found that with the 
 shorter arc the frequency of occurrence of these short-circuits 
 was considerably higher than was the case when the arc was 
 increased in length. To all appearances the arc was absolutely 
 steady and continuous and there was no indication either by 
 observation of the arc itself or of the instruments that these 
 phenomena were occurring. 
 
 Some Work Performed By the Machine, The principal 
 field for an automatic arc welding machine is where a consider- 
 
220 ELECTRIC WELDING 
 
 able amount of welding is required, the operations being a 
 continuous repetition of duplicate welds. Under these condi- 
 tions one can economically provide jigs and fixtures for 
 facilitating the handling of the work and the clamping. Thus 
 can be reaped the benefit of the increased speed in the actual 
 welding which would be lost if each individual piece had to 
 be clamped and handled separately. 
 
 Examples of different jobs done with this machine, using 
 various feeding and holding methods, are shown in the accom- 
 panying cuts. Fig. 172 is a worn pulley seat on an electric 
 motor shaft built up and ready to be re-turned to size. 
 
 It is possible to build up pulley and pinion seats, also worn 
 bearings, without removing the armature or rotor from the 
 
 m 
 
 Fie. 172. Worn Motor Shaft Built Up. 
 
 shaft and in practically all cases without removing the wind- 
 ings due to the concentration of the heat at the point of the 
 weld. On shafts of this kind, 3 to 4 in. in diameter, the figures 
 are: current 115 amp.; arc voltage 14; electrode 3 / 32 in. in 
 diameter; travel, 6 in. per min. ; rate of deposit about 2.1 Ib. 
 per hour. 
 
 Similar work on a 14-in. shaft where the flywheel seat 
 21 in. long was turned undersize, was as follows: metal about 
 Vie i n - deep was deposited over the undersize surface, using 
 current, 190 amp.; arc voltage 18; electrode -J in. diameter; 
 travel 4 in. per min.; rate of deposit, about 2 Ib. per hour; 
 welding time, 16 hr. ; machining time, 4 hr. 
 
 Fig. 173 shows worn and repaired crane wheel flanges. 
 These are easily handled by mounting on a mandrel in a lathe, 
 
AUTOMATIC ARC WELDING 
 
 221 
 
 and placing the welding machine on a bracket bolted to the 
 cross-slide or the saddle. On wheels of this type 22 in. in 
 diameter, the time taken to weld by hand would be about 
 12 hr. and by machine 2 hr. ; machining time 4 hr. ; approximate 
 cost by hand welding $9; by machine $4. 
 
 i 
 
 
 
 FlG. 173. Worn and Repaired Crane Wheels. 
 
 FIG. 174. Welded Automobile Hub Stampings. 
 
 Fig. 174 is an automobile wire wheel hub stamping, to 
 which a dust cover was welded as shown. Joint was between 
 metal 1 / 16 and Vie in. thick. Current 100 amp.; arc voltage, 
 14 ; travel 10 in. per min. ; electrode 3 / 32 in. diameter. 
 
222 
 
 ELECTRIC WELDING 
 
 Fig. 175, welded automobile rear-axle housing, 3 / 16 i n - thick ; 
 current 120 amp.; arc voltage 14; travel 6 in. per min. ; elec- 
 trode diameter 3 / 82 in. 
 
 Fig. 176, welded tank seam; metal -J in. thick; current 140 
 arnp. ; arc voltage 14 ; travel, 6 in. per min. ; time for welding 
 ten tanks by hand, 4 hrs. 40 min. ; by machine, 2 hrs. 
 
 FIG. 175. Welded Bear- Axle Housing. 
 
 Tables XVIII and XIX give an idea of the speed of welding 
 which may be expected, but it should be borne in mind that 
 these figures are actual welding speeds. It is necessary to 
 have the material properly clamped and supported and to have 
 it travel past the arc at a uniform speed. In some cases the 
 
 FiG. 176 Welded Straight Tank Seam. 
 
 figures given have been exceeded and under certain special 
 conditions it may be desirable to use lower values than those 
 given. 
 
 TABLE XVIII. SEAM WELDING 
 
 Thickness in Inches 
 0.040 
 1/16 
 1/8 
 3/16 
 
 Amperes Speed, Inches Per Minute 
 45 to 50 20 to 30 
 
 50 to 80 15 to 25 
 
 80 to 120 6 to 12 
 
 100 to 150 4 to 6 
 
AUTOMATIC ARC WELDING 223 
 
 TABLE XIX BUILDING UP (WHEELS OR SHAFTS) 
 
 Diameter or 
 
 Electrodes, 
 
 
 Speed, In. per 
 
 Lb. Deposit 
 
 Thick., In. 
 
 Dia., In. 
 
 Amperes 
 
 Min. 
 
 Per Hour 
 
 Up to 1" 
 
 V- 
 
 60 to 90 
 
 11 to 13 
 
 1.04-1.56 
 
 Up to 3" 
 
 % 
 
 90 to 120 
 
 6 to 8 
 
 1.59-2.1 
 
 Over 3" 
 
 V- 
 
 120 to 200 
 
 4 to 6 
 
 2.5 -4.5 
 
 A SEMI-AUTOMATIC ARC-WELDING MACHINE 
 
 A paper on " Welding Mild Steel," by H. W. Hobart, was 
 read at the New York meeting of the American Institute of 
 Mining and Metallurgical Engineers in 1919. In discussing 
 this paper Harry D. Morton, of the Automatic Arc Welding 
 Co., Detroit, brought out some interesting things relating to 
 Automatic Arc Welding: 
 
 "The generally accepted theory of the electric arc is that part of the 
 electrode material is vaporized, and that this vaporous tube or column 
 forms a path for the electric current. As a result of the vaporous 
 character of the current path, all arcs are inherently unstable; and the 
 maximum of instability is no doubt found in that form of arc employed 
 for metallic-electrode welding purposes. We here have, in conjunction with 
 the natural instability characteristic of all arcs rapidly fusing electrode 
 materials and the disturbing effect of the constant passage through the 
 arc of a large quantity of molten metal to form the weld. This molten 
 metal must pass through the arc so rapidly that it will not be injured 
 or materially contaminated; otherwise the weld will be useless. Prima 
 facie, the combination of these unfavorable conditions would seem to 
 justify fully the skepticism of most electrical engineers as to the possibility 
 of affecting such control of the metallic arc as to permit of uniformity 
 and continuity in welding results. In addition, there is another and more 
 important factor, and one that seriously mitigates against this desired 
 uniformity and continuity; namely, the personal equation of the operator. 
 The consensus of opinion, so far as is known to the writer, seems to be 
 that about 95 per cent, of the welding result is dependent on the skill 
 of the operator and that at least six months' practice is necessary to 
 acquire reasonably satisfactory proficiency. 
 
 "As the result of thousands of observations of welds produced auto- 
 matically (wherein the personal equation is entirely eliminated), the writer 
 inclines toward the theory that the molten electrode material passes through 
 the arc in the form of globules; and that where |-in. electrode material 
 is employed with a current of about 150 amp. these globules are deposited 
 at the rate of approximately two per second. The passage through the 
 arc of each globule apparently constitutes a specific cause of instability 
 in addition to those existent with slowly consumed electrodes. This 
 hypothesis seems to be borne out by ammeter records, typical specimens 
 of which appear in Fig. 177, together with the fact that the electrode 
 
224 
 
 ELECTRIC WELDING 
 
 fuses at the rate of about 0.20 in. per see. Moreover, the globules appear 
 to be approximately equal in volume to a piece of wire 0.125 in. in 
 diameter and 0.10 in. long. 
 
 ' ' Assuming this theory to be correct, to maintain a uniform arc length 
 in manual welding, the operator must feed the electrode toward the work 
 
 FiG. 177. Typical Ammeter Charts of Operation of Morton Automatic, 
 Metallic-Electrode Arc- Welding Machine. 
 
 Average Time about 1 Min. 45 Sec. 
 
 at the rate of 0.10 in. upon the deposition of each globule; in other words, 
 0.10 in. twice per second, a synchronism beyond human attainment. 
 Simultaneously with such feeding, the arc must be moved over the work 
 to melt the work material, distribute the molten electrode material, and 
 form the weld. Inasmuch as the effect of the arc is highly localized. 
 
AUTOMATIC ARC WELDING 225 
 
 it is reasonable to suppose that different parts of the welding area present 
 relatively wide variations in respect to temperature, fluidity, and conduc- 
 tivity of the molten mass controlling factors not within the ken of the 
 human mind. The situation is further complicated by the facts that 
 neither the welding wire nor the work material is uniform in fusibility 
 or in conductivity, and that the contour of the work varies continually 
 as its surface is fused and the molten metal is caused to flow. The belief 
 is general that a very short arc is productive of the best welding results; 
 but it is an arc of this character that makes the greatest demands on 
 the skill of the operator, for there is always the danger that the electrode 
 will actually contact with the work and destroy the arc. 
 
 ''As the fusing energy of the arc varies widely with fluctuations in 
 the arc length and as the uniformity of the weld depends on the constancy 
 and correctness of this fusing energy, it seems remarkable that operators 
 are able ever to acquire such a degree of skill as to enable them to produce 
 welds that are even commercially satisfactory. Further, so far as the 
 writer is informed, there is no means, other than such as would be 
 destructive, for determining whether a completed weld is good or bad. 
 The logical solution appeared to be the elimination of the personal equation 
 and the substitution therefor of means whereby tendencies toward variations 
 in the arc would be caused automatically to correct themselves, just as 
 a steam engine, through the action of its governor, is caused to control 
 its own speed. 
 
 Methods of Mechanically Stabilizing and Controlling the Arc. Our 
 efforts for a number of years have been directed toward stabilizing and 
 controlling the metallic arc, and applying such stabilizing and controlling 
 means to two general lines of welding machinery: (1) Machines for 
 automatically feeding the electrode wire, with reference to the work, and 
 producing simultaneously therewith -relative movement between the wire 
 and the work, and (2) what, for lack of a better term, might be called 
 a semi-automatic machine, in which the feeding of the electrode and the 
 control of the arc are accomplished automatically but the traversing of 
 the electrode with reference to the work is manually effected by the operator, 
 permitting him the exercise of judgment with reference to the quantity 
 of metal to be deposited in various parts of the groove. The automatic 
 machine has been in successful operation for a long period and the semi- 
 automatic machine for about five months. While the goal was not attained 
 without many difficulties and a great expenditure of time and money, the 
 results have been surprisingly successful. 
 
 ' ' Because of the lack of any definite data as to what actually occurs 
 in this form of arc, or why it occurs, due, no doubt, to the impossibility 
 of differentiating between phenomena that are characteristic of the arc 
 and phenomena due to the personal equation of the welder, it seemed 
 logical that the initial step should be to so environ the arc that it would 
 not be subject to erratic extraneous influences, to the end that reasonably 
 definite determinations might be substituted for scientific speculation. In 
 the design and construction of the machines, great care was exercised 
 to minimize the possibility of mechanical defects that might lead to 
 
226 ELECTRIC WELDING 
 
 erroneous conclusions. Starting with the assumption that the work could 
 only be based on open-minded observation of the behavior of the arc 
 under machine control, an automatic welding machine was built in which 
 was incorporated the greatest possible number of adjustable features, in 
 order that, if necessary, it might be possible to wander far afield in the 
 investigations. This adjustability has proved invaluable in that it has 
 permitted logical, consistent, and sequential experimenting over a very 
 wide range of conditions. Working under these favorable circumstances, 
 there were soon segregated a few clearly demonstrable facts to serve as 
 a foundation for the structure, which has since been added to, brick by brick, 
 as it were. 
 
 1 * Efforts have been directed toward the practical rather than the 
 scientific aspect of the subject. The operation of the automatic machines 
 has brought to light many curious and interesting phenomena, some of 
 which appear to negative conclusions heretofore formed which have been 
 predicated upon observations made in connection with manual welding. 
 It is hoped that these and other phenomena, which can thus be identified 
 as purely arc characteristics, will be the subject of profitable scientific 
 investigation when time is available for this purpose. 
 
 ' ' In the five forms of machines made in the course of the development, 
 the welding wire is automatically fed to the arc; and, in the first four 
 machines, the relative movement between the work and the welding wire 
 is automatically and simultaneously effected. Early in his investigations, 
 the writer concluded that a substantial equilibrium must be maintained 
 between the fusing energy of the arc and the feeding rate of the welding 
 strip; and it soon became evident that if the welding strip is mechanically 
 fed forward at a uniform rate equal to the average rate of consumption 
 with the selected arc energy, this equilibrium is actually maintained by 
 the arc itself, which seems to have, within certain circumscribed limits, 
 a compensatory action as follows: When the arc shortens, the resistance 
 decreases and the current rises. This rise in current causes the welding 
 strip to fuse more rapidly than it is fed, thereby causing the arc to lengthen. 
 Conversely, when the arc lengthens, the resistance increases, the current 
 falls, the welding strip is fused more slowly than it is fed, and the moving 
 strip restores the arc to its normal length. 
 
 11 While this compensatory action of the arc will maintain the necessary 
 equilibrium between the fusing energy and the feeding rate under very 
 carefully adjusted conditions, this takes place only within relatively narrow 
 limits. It was very apparent that, due to variations in the contour of 
 the work, and, perhaps, to differences in the fusibility or conductivity of 
 the welding strip or of the work, the range of this self -compensatory action 
 of the arc was frequently insufficient to prevent either contacting of the 
 welding strip with the work or a rupture of the arc due to its becoming 
 too long. The problem that arose was to devise means whereby the natural 
 self-compensatory action of the arc could be so greatly accentuated as to 
 preclude, within wide limits, the occurrence of marked arc abnormalities. 
 There was ultimately evolved, by experiment, such a relation between the 
 fusing energy of the arc and the feeding rate of the welding strip as to 
 
AUTOMATIC ARC WELDING 
 
 227 
 
 give the desired arc length under normal conditions; and tendencies toward 
 abnormalities in arc conditions, no matter how produced, were caused to 
 
 FIG. 178. Piloted Cup Automatically Welded by Metallic-Electrode Arc 
 Process to Tube to Form 75-MM. Shrapnel Shell. 
 
 Analysis of Electrode Material: Silicon, 0.02 Per Cent; Sulphur, 0.013 Per Cent; 
 Phosphorus, 0.07 Per Cent; Manganese, Trace; Carbon, 0.07 Per Cent; Aluminum, 
 0.038 Per Cent. 
 
 FIG. 179. Piloted Cup Automatically Welded by Metallic-Electrode Arc 
 
 Process to Tube to Form 75-MM. Shrapnel Shell. 
 
 Analysis of Electrode Material: Silicon, 0.03 Per Cent; Sulphur, 0.049 Per Cent; 
 Phosphorus, 0.008 Per Cent; Manganese, 0.31 Per Cent; Carbon, 0.28 Per Cent. 
 
 bring into operation compensatory means for automatically, progressively, 
 and correctively varying this relation between fusing energy and feeding 
 
228 
 
 ELECTRIC WELDING 
 
 rate, such compensatory means being under the control of a dominant 
 characteristic of the arc. In their ultimate forms, the devices for effecting 
 the control of the arc are simple and entirely positive in action, making 
 discrepancies between fusing energy and feeding rate self -compensatory 
 throughout widely varying welding conditions. For instance, the shrapnel 
 shell shown in Fig. 178 was automatically welded with wire differing 
 greatly in chemical constitution from that used on the shell shown in 
 Fig. 179 (see analyses), yet no change was made in either the mechanical 
 or the electrical adjustments. The radically different welding conditions 
 were compensated for solely by the operation of the automatic control. 
 The electrode materials used for the shells shown in Figs. 180 and 181 
 
 FIG. 180. Piloted Cup Automatically Welded by Metallic-Electrode Arc 
 Process to Tube to Form 75-MM. Shrapnel Shell 
 
 Analysis of Electrode Material: Silicon, 0.02 Per Cent; Sulphur, 0.032 Per Cent; 
 Phosphorus, 0.008 Per Cent; Manganese, 0.20 Per Cent; Carbon, 0.18 Per Cent. 
 
 differed so greatly from those employed respectively in welding the shells 
 shown in Figs. 178 and 179 that a change in the relation between fusing 
 energy and feeding rate had to be made manually. After this adjustment 
 was made, the shells were welded with their respective electrodes, which varied 
 widely in their chemical constitution, without further manually changing 
 either the mechanical or the electrical conditions. 
 
 "In a recent test of the semi-automatic machine, shown in Fig. 182, 
 successful welds were made under the condition that the impressed voltage 
 of the welding generator was changed throughout a range of from 50 to 65 
 volts, without necessitating any manual adjustment. The only observable 
 effects of the wide variations in the supply voltage were slight differences 
 in the arc length. In short, the compensatory action of the control has 
 proved effective over a wide range of welding conditions, not only as to 
 
AUTOMATIC ARC WELDING 229 
 
 the electrical supply and chemical constitution of both electrode and work 
 materials, but also as to extensive variations in the contour of the work 
 and in many other particulars. This makes it seem apparent that the 
 machines do not represent merely successful laboratory experiments but 
 are suited to the requirements of actual commercial welding. 
 
 "One particularly interesting observation resulting from the experiments 
 is that the angle of inclination of the electrode with reference to the work 
 is very important. An angular variation of 5 deg. will sometimes determine 
 the difference between success and failure in a weld. About 15 deg. from 
 the perpendicular works well in many cases. In welding some materials, 
 the electrode should drag, that is, point toward the part already welded 
 rather than toward the unwelded part of the seam. 
 
 FlG. 181. Piloted Cup Automatically Welded by Metallic-Electrode Arc 
 Process to Tube to Form 75-MAI. Shrapnel Shell. 
 
 Analysis of Electrode Material: Silicon, 0.04 Per Cent; Sulphur, 0.016 Per Cent; 
 Phosphorus, O.OfiS Per Cent- Manganese, None; Carbon, 0.24 Per Cent. 
 
 "While it has been customary in some welding systems to provide 
 means whereby extra resistance is inserted in series with the arc at the 
 instant of the initial contact which starts the flow of current, the resistance 
 being automatically cut out upon the striking of the arc, experience with 
 the automatic machines indicates that this is quite unnecessary. 
 
 "Early in the experiments, it was noted that in many cases there was 
 a decidedly marked affinity between particular electrode materials and 
 particular work materials. A slight change in either element affects the 
 degree of this affinity. While it has invariably been possible to contiol 
 and maintain the arc and weld continuously, in some instances incom- 
 patibility between electrode material and work material has been productive 
 of interesting phenomena. For instance, the combination of work material 
 (steel of about 0.45 per cent, carbon content) and the particular electrode 
 
230 
 
 ELECTRIC WELDING 
 
 material used in Fig. 178 produced an arc that was remarkably quiet and 
 free from sputtering. Throughout the weld, this arc was suggestive of 
 the quiet flame of a candle or lamp, the erratic behavior that we are 
 accustomed to associate with the ordinary metallic arc being absent. The 
 effect is reflected in the uniform deposition of the welding material. 
 
 "On some classes of work materia 1 Bessemer wire, which some authorities 
 claim cannot be used in metallic-electrode arc welding, produces an arc 
 
 FIG. 182. Morton Semi-Automatic Metallic-Electrode Arc-Welding Machine. 
 
 The Electrode is automatically fed to the arc, which is automatically maintained 
 while the machine is manually moved along the groove to be welded. 
 
 and a weld very satisfactory in appearance. On other work material, the 
 Bessemer wire arc is violently explosive. These explosions are accompanied 
 by quite sharp reports and the scattering over some considerable distance 
 of globules of molten metal frequently s / 82 in. or more in diameter. Under 
 certain other conditions, apparently growing out of incompatibility between 
 the work material and the electrode material, the oxygen flame accompany- 
 ing the arc gyrates very rapidly about the arc, producing an effect sug- 
 gestive of the ' whirling dervish. ' 
 
AUTOMATIC ARC WELDING 231 
 
 "From both the practical and the scientific points of view, the writer 
 has experimented quite extensively with varying combinations of work 
 material and electrode material. Throughout all the differences in arc 
 conditions, many of which palpably accentuate the natural inclination 
 toward instability, the control has so operated as to justify the expression 
 'the arc persists.' 
 
 "Generally speaking, the Swedish and Norway iron wires seem to 
 produce more quiet arcs and, possibly, a more uniform deposition of electrode 
 material, than do wires of other classes. These welds may perhaps be 
 found to be slightly more ductile than those made with wires of other 
 chemical composition. On the other hand, these soft wires, although un- 
 doubtedly of relatively high fusibility, do not, for some reason, seem to 
 produce an arc that cuts into some work material as deeply as might be 
 desired, nor as deeply as do the arcs formed with certain other kinds of 
 wire. Considered from every angle, the writer is disposed to regard the 
 Roebling welding wire as the best he has thus far tested for use on mild 
 steel. The wire produces a reasonably quiet arc which seems to cut into 
 the work to more than the ordinary depth, while, at the same time, the 
 electrode material is fused with more than average rapidity thus increas- 
 ing the welding rate. 
 
 ' ' While scientists will no doubt ultimately arrive at the correct hypothesis 
 for solving the problem of why one combination of electrode material and 
 work material is productive of better results than can be obtained with 
 another combination, the writer's conclusion is that, with the data at 
 present available, the determinations must be made by actual experimenting 
 having in mind the qualities desired in the particular weld, such as 
 ductility, tensile strength, elongation, and elastic limit. Inasmuch as it 
 is possible, with the automatic machine, to maintain arc uniformity with 
 practically any kind of electrode material and to produce welds which, 
 under low magnification, at least, appear to be perfect, and which respond 
 favorably to ordinary tests such as bending, cutting and filing, it is reason- 
 able to conclude that proper selection of electrode material will be productive 
 of perfect welds on any kind of work material. To date, no steel has been 
 tested on which apparently satisfactory welds could not be made. High- 
 speed tungsten steel has been successfully welded to cold-rolled shafting, 
 using Bessemer wire as electrode material, as is shown in Fig 183. 
 Ordinary steels varying in carbon content from perhaps 0.10 to 0.55 per 
 cent, have been welded with entire success. 
 
 "Because of the fact that the complete welding operation has been 
 automatic and may be continued for a considerable length of time, say 
 5 min., an exceptional opportunity has been afforded for close concentration 
 upon the study of the appearance of the arc. What seems to occur is 
 that the molten metal in the crater is in a state of violent surging, sug- 
 gestive of a small lake lashed by a terrific storm. The waves are dashed 
 against the sides of the crater, where the molten metal of which they 
 are composed quickly solidifies. The surgings do not seem to synchronize 
 with nor to be caused by the falling of the globules of molten metal into 
 the crater, but seem rather to be continuous. They give the impression 
 
232 
 
 ELECTRIC WELDING 
 
 that the molten metal is subjected to an action arising from the disturbance 
 of some powerful force associated with the arc such, for instance, as 
 might result from the violent distortion of a strong magnetic field. Alto- 
 gether, the crater phenomena are very impressive; and the writer hopes 
 ere long to be able to have motion pictures made which, when enlarged, 
 should not only afford material for most fascinating study, but also throw 
 light upon some of the mysterious happenings in the arc. 
 
 So far, electrode wires I in. in diameter have been chiefly used in 
 the machines. Successful welds have been made with current values ranging 
 from below 90 to above 200 amp., at impressed voltages of 40, 45, 50, 
 
 FIG. 183. Tungsten High-Speed Eing Automatically Welded by Metallic- 
 Electrode to Cold-Kolled Core to Form Milling-Cutter Blank. 
 
 55, 60, 65 and 80. Under these varying conditions, the voltage across 
 the arc has been roughly from 16 to 22. The machines have thus far been 
 run only on direct current. Inasmuch as it is possible, by electrical and 
 mechanical adjustments, to establish nearly any arc length that may be 
 found to be most desirable for a particular class of work, and as the 
 control system will maintain substantially that arc length indefinitely, the 
 fully automatic type of machine is nearly as certain in operation as a lathe, 
 drilling machine, or any other machine tool. 
 
 ' ' The tool shown in Fig. 182 weighs about 10 Ib. The operator draws 
 the tool along the groove to be welded at such a rate as will result in 
 the deposition of the quantity of metal required to satisfactorily effect the 
 weld. This tool is intended for use in the many restricted spaces en- 
 
AUTOMATIC ARC WELDING 233 
 
 countered in ship welding, which would be relatively inaccessible to a fully 
 automatic machine. In its use, the skill required by the operator is reduced 
 to a minimum. After one man had practised with the welding tool for 
 not more than 2 hr., the opinion was expressed that it would require six 
 months to train a welder to such a degree of proficiency as to enable him 
 to make a weld equally good in appearance. 
 
 "Mr. Hobart, says 'There is always a matter of a 0.10 in. or more 
 between the end of the welding rod and the work.' While undoubtedly 
 it is difficult, if not impossible, to maintain in manual welding an arc 
 shorter than this, the writer has frequently, with the automatic machines, 
 made continuous and strikingly good welds with arcs of much less length. 
 In fact, in some cases there has been continuously maintained an arc so 
 short that there hardly seemed to be any actual separation. The writer 
 
 FIG. 184. No. 11 Gage Steel Tubing Automatically Welded by Metallic- 
 Electrode Arc Process at the Rate of One Foot per Minute. 
 
 has even wondered whether, under these conditions, there was not a close 
 approach to casting with a continuous stream of fluid metal acting as the 
 current conveyor in lieu of or in parallel with the usually assumed vapor 
 path. The work that has been done indicates that under automatic control 
 much shorter arcs can be utilized than have hitherto been deemed possible, 
 and with probable marked gain in quality of work in some instances; also, 
 that there is much to be learned as to the mode of current action and 
 current conduction in such an arc. 
 
 "With the automatic machine, black drawing steel 0.109 in. thick 
 has been welded at the rate of 22 in. per minute. A Detroit manufacturer 
 welded manually with oxy-acetylene at the rate of four per hour a large 
 number of mine floats 10 in. in diameter, made of this material. The 
 automatic machine made the welds at the rate of forty per hour. Liberty 
 
234 
 
 ELECTRIC WELDING 
 
 motor valve cages 2| in. in diameter have been welded to cylinders in 
 36 sec., as against about 5 min. required for manual welding. No. 11 
 gage steel tubing, shown in Fig. 184, has been welded, with an unnecessarily 
 
 FIG. 185. Two i-in. Ship Plates Automatically Welded by Metallic- 
 Electrode Arc Process to Form Lap Joint. 
 
 FlG. 186. Two -in. Ship Plates Automatically Welded by Metallic- 
 Electrode Process to Form Butt .Joint. 
 
 heavy deposit of metal, at the rate of 1 ft. per minute. The productive 
 capacity of the machines so far made has been from three to ten times 
 that of manual welding methods, depending on the thickness of the work 
 
AUTOMATIC ARC WELDING 
 
 235 
 
 material; the difference in favor of automatic welding varies inversely 
 as such thickness. The writer is now designing an improved type of 
 machine for use especially on heavy work, with which machine it is expected 
 to be able automatically to lapweld -in. ship plates, in the manner shown 
 in Fig. 185, at the rate of 15 ft. per hour. One of the largest shipbuilding 
 concerns in the United States reports that the general average of all its 
 manual welders on this class of work is from 1 ft. to 18 in. per hour. 
 Other specimens of automatic welding on ship plates are shown in Figs. 
 186 and 187. 
 
 * ' Bare wire only has been used in the automatic machines ; and the 
 results obtained seem to indicate that the covering of the electrodes is an 
 expensive superfluity. If the chief advantage of the covered electrode lies 
 in the ability of the operator to maintain a very short arc, an arc equally 
 short and possibly shorter can be continuously maintained by the automatic 
 machine using bare electrodes. 
 
 "No attempt has thus far been made to use the automatic machines 
 
 FIG. 187. Two i-in. Ship Plates Automatically Welded by Metallic-Elec- 
 trode Arc Process, Showing First of Three Layers to Form Lap Joint. 
 
 on overhead work. The welds made with the fully automatic machine have 
 been of three kinds, the usual longitudinal form, annular about a horizontal 
 axis, and annular about a vertical axis. 
 
 "As far as the maintenance of arc uniformity and the apparent 
 character of the welds are concerned, the writer has repeatedly welded 
 with wire showing evidence of pipes and seams, as well as with rusty 
 wire and with wire covered with dirt and grease. In this connection it 
 may be said that no pains is ever taken to remove rust, scale, or slag 
 from the work material even where welds are superimposed. Apparently 
 under uniform conditions of work traverse, arc length, and electrode angle 
 of inclination, such as are possible in the automatic machine, impurities 
 vanish before the portion of the work on which they occur reaches the 
 welding area of the arc. 
 
 "The writer is fully convinced that with the use of the automatic 
 machine, ductility, like other physical properties in the weld, can be con- 
 trolled "by proper selection of electrode wire, in conjunction with electrical 
 
236 
 
 ELECTRIC WELDING 
 
AUTOMATIC ARC WELDING 237 
 
 and mechanical adjustments best suited to the particular purpose in view. 
 Automatic welds have repeatedly been made on 5 /i 6 -in. mild steel which, 
 when subjected to a 90-deg. bend, showed a marked extrusion of the 
 welded material but no sign of fracture. When the welded pieces are 
 cut with a hacksaw, it is very unusual to be able to note any difference 
 in cutting qualities between the unwelded and the welded parts. 
 
 "While the automatic machine has not been used on metal less than 
 0.109 in. thick, it is fair to presume that, with proper adjustments, entirely 
 satisfactory results can be obtained on much thinner work particularly 
 if the nature of the work is such as to permit of the use of a chill. The 
 best method in welding very light metal seems to be to use a small electrode, 
 a relatively low current, and a high rate of work traverse. In this way 
 welding conditions may be controlled to almost any desired extent, because 
 
 FIG. 189. How the Metal Edges Are Welded. 
 
 the heating action of the arc can be modified, its effect intensely localized, 
 and the edges to be welded subjected to the fusing action for as brief 
 a time as might be found necessary to prevent burning of the metal. 
 These conditions, which seem to be requisite in order to successfully weld 
 very thin material, cannot be met by the manual welder. It is here that 
 the deficiencies incident to the personal equation become most apparent. 
 A very slight variation in arc length or the least hesitancy in moving the 
 arc over the work will almost certainly result in its being burned through. 
 In short, this class of welding calls for a coordination of faculties and a 
 delicacy of manipulation beyond the capabilities of the most skillful manual 
 electric welder. Therefore this work is usually done with the oxy-acetylene 
 flame, wherein fusing conditions arc far more easily controlled than is 
 possible in manual metallic electrode arc welding." 
 
 SHEET METAL ARC- WELDING MACHINE 
 
 The machine shown in Fig. 188 is used by the General 
 Electric Co., Schenectady, N. Y., for arc-welding corrugated 
 steel tank work. The seams are 116 in. long, and the arc 
 
238 ELECTRIC WELDING 
 
 is applied by means of a tapered carbon pencil 6 in. long, J 
 in. in diameter at the large end and -J in. at the arc end. This 
 concentrates heat where wanted. No metal is supplied to the 
 weld, as the arc is employed simply to fuse the upturned edges 
 as shown in Fig. 189. The metal welded is Vie and 3 / 32 in- 
 thick. 
 
 The speed on 1 / 16 -in stock is 5 1 / 2 in. per minute with a 
 d.c. current of 45 amp., and 75 volts. On 3 / 32 -m. stock the 
 speed is the same but 70 amp. and 75 volts d.c. current is 
 used. 
 
CHAPTER XII 
 BUTT-WELDING MACHINES AND WORK 
 
 Aside from, arc-welding machines, which have already been 
 described, electric welding machines may be all included under 
 one head Resistance Welding Machines. These may be 
 divided into butt-, spot-, seam-, mash- and percussive-welding 
 classes. The first three are sometimes, for manufacturing pur- 
 poses, used in combinations in the same machine, such as a 
 spot-and-seam machine or a butt-and-spot-welding machine, 
 and so on. This does not mean that these different methods 
 of welding are carried on at the same time, but that a welder 
 can do work on the same machine by simply shifting the work, 
 or a part of the fixture. 
 
 In butt-welding, alternating current, single phase, of any 
 commercial frequency such as 220, 440 or 550 volts, 60 cycles, 
 is commonly used. Lower voltages and lower frequencies can 
 be used, but they add to the cost of the machine. The machine 
 can be used on one phase of a two-phase or a three-phase 
 system, but cannot be connected to more than one phase of 
 a three-phase circuit. Direct current is not used because there 
 is no way of reducing the voltage without interposing resist- 
 ance, which wastes the power. As an example, a d.c. plating 
 dynamo will give approximately 5 volts, which will do for 
 certain kinds of welding, but for lighter work, less current is 
 needed. If resistance is used to reduce the current this resist- 
 ance is using up power just as if it were doing useful work. 
 The voltage at the weld will run from 1 to 15 volts, depending 
 on the size of the welder and work. To obtain this low voltage, 
 a special transformer inside the machine reduces the power 
 line voltage down to the amount required at the weld. The 
 transformer is placed within the frame of the machine, as 
 shown in Fig. 190. The secondary winding of the transformer 
 is connected to the platens by means of flexible copper leads. 
 
 239 
 
240 
 
 ELECTRIC WELDING 
 
 From the platens the welding current travels to the work 
 clamps and through them to the pieces to be welded. As the 
 parts to be welded are brought into contact a switch is thrown 
 in and the current traveling across heats the ends of the work 
 and when the proper welding heat is reached the operator 
 
 WORK STOP 
 
 ClAMP ADJUSTMENT 
 CLAMP JAW WITH STEEL DIE 
 I/COPPER DIE 
 
 CLAMP RELEASE 
 CLAMP LOCKING 
 
 Fie. 190. Principal Parts of a Butt-Welding Machine. 
 
 pushes the two parts together and the weld is completed. Since 
 the current value rises as the potential falls in the secondary 
 circuit, and since the heating effect across the work is directly 
 proportional to the current value it will be easily seen why 
 a transformer is necessary to produce a heavy current by lower- 
 
BUTT-WELDING MACHINES AND WORK 
 
 241 
 
 ing the line potential. Due to the intermittent character of 
 the load, there is no standard rating for welding transformers, 
 and different makers frequently give entirely different ratings 
 for their machines. However, regardless of the rating capacity 
 in kilowatts, there can be very little difference in the 
 actual amount of current consumed unless an especially bad 
 
 FIG. 191. Butt-Welding Machine with Work in Jaws. 
 
 transformer design is used. To heat a given size stock to 
 welding temperature in a given time requires an approximately 
 invariable amount of current. 
 
 The machine just illustrated, is shown at a slightly different 
 angle and with two pieces of rod in the jaws, in Fig. 191. 
 This is the Thomson regular No. 3, butt-welding machine. It 
 
242 
 
 ELECTRIC WELDING 
 
 FIG. 192. Details of Foot-Operated Clamping Mechanism. 
 
 PlG. 193. A Hand-Operated Clamp. 
 
 FIG. 194. Toggle-Lever Clamp for Bound Stock. 
 
BUTT-WELDING MACHINES AND WORK 
 
 243 
 
 has a capacity of rod from j to J in. in diameter or flat stock 
 up to Y 4 X2 in., in two separate pieces, or rings of Vie-in, 
 stock and not less than 2 in. in diameter. Hoops and bands 
 up to Yi 6 Xl 3 /4 in. and not less than 9V 2 * n - diameter when 
 held below the line of welding, may also be welded. With 
 jaws specially made to hold the work above the line of welding 
 a minimum diameter of 4 in. is necessary. This machine will 
 produce from 150 to 200 separate pieces, 150 to 300 hoops, 
 or 300 to 400 rings per hour. The lower dies are of hard 
 drawn copper with contact surfaces lVsX2 in.X2V 16 in. thick. 
 
 FIG. '195. Clamping Device for Heavy Flat Stock. 
 
 Standard transformer windings are for 220, 440 and 550 volts, 
 60 cycle current. Current variation for different sizes of stock 
 is effected through a five-point switch shown at the left. 
 Standard ratings are 15 kw. or 22 kva., with 60 per cent power 
 factor. The dies are air cooled but the clamps to which the 
 dies are bolted are water cooled. This type of machine occupies 
 a floor space 40X33 in., and is 53 in. high. The weight is 
 1,750 Ib. A close-up view of the treadle-operated clamping 
 .jaw mechanism is given in Fig. 192. 
 
 The method of operating the clamping jaws differs accord- 
 
244 
 
 ELECTRIC WELDING 
 
 ing to the size of the machine and the work that is to be 
 done. On some of the smaller machines the type of hand- 
 operated clamp shown in Fig. 193 is used. On other machines, 
 intended to handle round stock principally, the toggle lever 
 clamp shown in Fig. 194 is used. For very heavy flat stock, 
 the hand-lever clamping mechanism, shown in Fig. 195, is 
 used. On some of the machines used on small repetition work 
 the clamps and switch are automatically cam-operated as shown 
 in Figs. 196 and 197. The first machine is a bench type used 
 
 FIG. 196. A Cam-Operated Machine. 
 
 for welding on twist drill shanks, and the second machine is 
 used for welding harness rings. These jobs are, of course, 
 merely examples as the machines are adapted for all sorts 
 of the smaller welding jobs. Spring pressure, toggle-lever or 
 hydraulic pressure arc used to give the final "shove-up" accord- 
 ing to the machine used or weight of stock being welded. 
 
 In welding hard steel wire of over 35 per cent carbon 
 content, it is necessary to anneal the work for a distance of 
 about 1 in. on each side of the wold. This is due to the fact 
 
BUTT-WELDING MACHINES AND WORK 
 
 245 
 
 that the wire on each side is rendered brittle by the cooling 
 effect of the clamping jaws. To accomplish this annealing, 
 all the small Thomson machines used for this work are equipped 
 with a set of V-jaws outside of the clamping jaws, as shown 
 in front in Fig. 198. The wire is laid in these V's with the 
 
 FIG. 197. Automatic-Operated Machine Welding Harness Rings. 
 
 weld half way between and the current is thrown on intermit- 
 tently by means of a push button until the wire has become 
 heated to the desired color, when it is removed and allowed 
 to cool. The annealing of a small drill is shown in Fig. 199. 
 The process of welding and annealing 12 gage, hard steel wire, 
 
246 
 
 ELECTRIC WELDING 
 
 FIG. 198. Machine Equipped with Annealing Device. 
 
 FIG. 199. Annealing a Small Drill. 
 
BUTT-WELDING MACHINES AND WORK 247 
 
 requires about 30 sec. when done by an experienced operator. 
 Copper and brass wire are easily welded in these same machines. 
 The machine shown will weld iron and steel wire from No. 
 21 B. & S. to J in. i n diameter and flat stock up to No. 25 
 B. & S.Xi in. wide. Production is from 150 to 250 welds per 
 hour, the actual welding time being 1| sec. on J-in. steel wire. 
 The clamps are spring-pressure, with adjustable tension 
 released by hand lever. The standard windings are furnished 
 for 110, 220, 440 and 550 volts, 60 cycles. Five variations are 
 made possible by the switch. The ratings are 1 kw. or 3 
 kva., with 60 per cent power factor. The weight is 120 pounds. 
 
 For use in wire mills where it is desired to weld a new 
 reel of wire to the end of a run-out reel on the twisting or 
 braiding machines, it has been found convenient to mount the 
 machine on a truck or. small bench on large casters. This 
 enables one to move the welder from one winding machine to 
 another very easily, to splice on new reels of small wire, the 
 electrical connection to the welder being made by flexible cord, 
 which is plugged into taps arranged at convenient points near 
 each winding machine. It is also desirable to mount on this 
 same bench a small vise in which to grip the wire to file off 
 the burr resulting from the push-up of the metal in the weld. 
 The average time required to weld, anneal and file up a 16-gage 
 steel wire with this bench arrangement is only about one 
 minute. The only preparation necessary for welding wire is 
 that the stock be clean and the ends be filed fairly square so 
 that they will not push by one another when the pressure 
 is applied. 
 
 In connection with welding wires and rods up to J in. 
 in diameter, Table XX will be found very handy. For sizes 
 from J to 2J in. the reader is referred to Table XXVI. 
 
 Examples of Butt- Welding Jobs. while, as a rule, it is 
 only necessary to have clean and fairly square ends for butt- 
 welding in some cases where small welding is to be done it 
 has been found best to bevel or V the abutting ends. This is 
 more apt to be the case with non-ferrous metals, however, than 
 with iron or steel. A notable example in the larger work is 
 in the scarfing of the ends of boiler tubes when butt-welding 
 is done. This phase of the question has apparently not been 
 given the attention it deserves, and some cases where welding 
 
248 
 
 ELECTRIC WELDING 
 
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BUTT-WELDING MACHINES AND WORK 
 
 249 
 
 lias been declared a failure in manufacturing may be laid 
 to the fact that the parts to be welded were not scarfed and 
 consequently would not stand the required tests after being 
 welded. As a general rule, a properly executed butt-weld 
 should, when reduced to the size of the original section, have 
 practically the same strength. 
 
 Although copper and brass rod and strip can be welded 
 
 FIG. 200. Typical Copper Welds. 
 
 with perfect success, owing to the nature of the metal it 
 requires a specially constructed machine to secure the best 
 results. Since copper has a very low specific resistance as 
 compared to iron or steel, it requires much more current to 
 melt it on a given size rod. A longer time is required also 
 to heat a given size of rod as compared to steel, but when 
 
 FlG. 201. Welded Aluminum Ring. 
 
 the plastic stage is reached the metal flows so rapidly that it 
 must be pushed up with tremendous speed or the molten 
 copper will flow out between the abutting ends. To effect this 
 rapid push-up of stock the platen on which the movable right- 
 hand clamp is mounted must move very freely indeed, neces- 
 sitating roller bearings on the larger sizes of machines. The 
 
250 
 
 ELECTRIC WELDING 
 
 pressure spring on the smaller machines must also be capable 
 of maintaining its tension through a longer distance than on 
 
 Fia. 202. A Steel Wire Weld. 
 
 FIG. 203. Welded Hoisting Drum Crank Forging. 
 
 FiO. 204. Large Welded Pinion Blank. 
 
 a machine for iron and steel, since more metal is pushed up 
 
 on a given size of copper rod than would be on steel or iron. 
 
 The properties of brass and also aluminum are practically 
 
BUTT-WKLDLNG MACHINES AND WORK 251 
 
 FIG. 205. Welding a Band Saw. 
 
 FIG. 206. Bandsaw Weld before and after Removing Flash. 
 
252 ELECTIC WELDING 
 
 the same as those of copper and therefore this special type 
 of machine is just as well adapted for these metals. 
 
 Typical copper welds are shown in Fig. 200. The one at 
 the left shows it just as it came from the machine, and the 
 one at the right with the flash partly removed. Fig. 201 
 shows an aluminum ring immediately after welding. A steel 
 wire weld is shown in Fig. 202, and a welded hoisting drum 
 crank in Fig. 203. This last illustration shows how some 
 drop forgings may be simplified and the cost of dies and 
 production lessened. A large pinion gear blank is shown in 
 Fig. 204. Made in this way, a large amount of time and metal 
 is saved. The way to weld pieces of large and small cross 
 section is described in the article on tool welding. 
 
 Band saws may be butt-welded as shown in Fig. 205. The 
 way a band saw looks after welding and after the flash is 
 removed is shown in Fig. 206. 
 
 T-WELDING 
 
 T-welding, which is a special form of butt-welding, is, as 
 its name implies, the process of making a weld in the shape 
 of the letter "T". Where it is desired to weld a piece of 
 iron to the middle of another bar of equal size or larger, it 
 becomes necessary to heat the top bar of the "T" to a bright 
 red; then bring the lower bar to the preheated one and again 
 turn on the current, when a weld can quickly be made. The 
 reason for doing this is as follows: The pieces are of unequal 
 area in cross-section at the junction of the two pieces. As 
 it takes longer to heat the upper part, the end of the lower 
 part of the "T" would burn before the upper piece would 
 reach the welding temperature. Preheating will equalize and 
 overcome this difficulty. Special machines known as "T" 
 welders are built for this class of work to facilitate the pre- 
 heating, when the highest possible production on this form 
 of weld is desired. 
 
 Automobile Rim Work. One of the largest applications of 
 butt- welding today is to be found in the automobile-rim in- 
 dustry. The special form of clamp shown in Fig. 195 was 
 especially designed to handle rims of all kinds and sizes. It 
 is not adaptable for any type of work other than flat stock, 
 
BUTT-WELDING MACHINES AND WORK 253 
 
 as the amount of jaw-opening is much smaller than the diameter 
 of equivalent section of round stock. 
 
 No backing-up stops of any kind are built for these machines 
 with rim-clamps, as stops are unnecessary for this class of 
 work. In order to secure sufficient gripping effect of the stock 
 to prevent it slipping in the clamp- jaws, the upper dies are 
 made of self-hardening steel with the gripping surface cor- 
 rugated. The lower dies, which carry all the current to the 
 work, are made of copper with Tobin-bronze shoes on which 
 the work rests, so as to give good conductivity and yet present 
 a hard wearing surface to the steel rim. These lower dies 
 must not only bear the gripping effort exerted by the steel 
 dies above, but also the weight of the rim, which, in large sizes, 
 amounts to considerable. 
 
 The method employed in welding automobile rims is the 
 "flash-weld" principle, wherein the current is first turned on 
 with the edges to be welded pulled apart. The pressure is 
 then applied gently to bring the abutting ends slowly together. 
 As uneven projections come into contact across from opposite 
 edges they are burned or "flashed" off, which is evidenced 
 by flying particles of burning iron. The pressure is gradually 
 increased, bringing more of the length of the opposite edges 
 into contact and when the "flash" throws out for the full 
 width of the rim which indicates the abutting ends are touch- 
 ing all the way across, the final pressure is quickly applied 
 as the current is turned off, thereby completing the weld. It 
 has been found that experienced operators on this kind of 
 work do not look at the weld itself but govern their actions 
 by the appearance of the amount of flash or sparks thrown 
 out. When this assumes the shape of a complete fan they know 
 it is the right moment to cut off the current and apply the 
 final pressure. 
 
 The burr or fin thrown up in this type of weld is very 
 short and very brittle, making its removal much easier than 
 would be the case with the heavy burr resulting from a slow 
 butt-weld. It is the common practice in rim plants to remove 
 the burr while it is still hot and with a pneumatic chisel or 
 a sprue cutter. The slight amount of burr then remaining 
 is ground off with a coarse abrasive wheel and the rim is ready 
 for the forming process. In most rim plants the operations 
 
254 
 
 ELECTRIC WELDING 
 
 of rolling, welding, chiseling burr, grinding burr, forming, 
 shaping, etc., fit in so closely to one another that a rim is 
 practically kept moving continuously from the time the flat 
 stock is put into the rolls until a finished rim emerges. The 
 welding operation itself on a rim blank for 30X3| tire size, 
 for instance, has an average production rate of 60 rims per 
 hour, some' concerns doing even better than this. On large 
 
 FIG. 207. Truck Rim "Welding Machine. 
 
 truck rims for solid tires, having a section of 16 Xf in. thick, 
 a production of 10 rims per hour is considered very good, 
 although there are concerns doing even better than this on 
 such heavy work. 
 
 The machine shown in Fig. 207 was specially designed for 
 handling heavy truck rims only. The lower jaws on this 
 welder are placed very low in order that the machine can 
 
BUTT-WELDING MACHINES AND WORK 255 
 
 be set in a comparatively shallow pit to bring the line of 
 weld on a level with the floor. This makes it possible, with 
 proper tracking arrangements, to roll heavy rims right onto 
 the lower dies without any lifting, the rim being rolled out 
 again after welding. The double oil-transformers used in this 
 welder hang below the base line, which necessitates a small 
 pit directly under the center of machine. Owing to this and 
 also the weight to be supported, a concrete foundation only 
 should be employed. 
 
 This machine has a capacity for stock |X8 to |X16 in., 
 or a maximum thickness of 1 in. with a cross-sectional area 
 of not over 7 sq. in. Rims with a minimum diameter of 30 in. 
 can be welded. The pressure is effected by twin hydraulic 
 
 FIG. 208. A Heavy Welded Eim. 
 
 cylinders operated from an external accumulator giving a 
 maximum pressure of 24 to 37 tons on the work. The voltage 
 windings are of the same capacity as for other machines. The 
 transformer is of the oil cooled type, and the ratings are 160 
 kw. or 266 kva., with 60 per cent power factor. Primary 
 windings of transformers are submerged in cooling oil con- 
 tained in casings. Platens on which the clamps are mounted 
 and the bodies of the lower jaws to which the contact shoes 
 are bolted, are water cooled. This machine is 66X101 in. and 
 66 in. high. The net weight is 14,000 pounds. 
 
 A heavy rim after welding is shown in Fig. 208. 
 
 Welding Pipe. In order to weld pipe and tubing in the 
 form of coils for condenser systems cooling tubes, heating 
 coils, etc., as shown in Fig. 209, it was found necessary to 
 
256 ELECTRIC WELDING 
 
 employ a special form of clamp wherein the jaws could be 
 set up high to give clearance above the pressure-device. The 
 thickness of the die and die-block to which it is bolted also 
 had to be reduced to a minimum so as to insert the jaws 
 between coils, since the pipe is coiled through each length and 
 then another length is welded on, which in turn is coiled, and 
 so on. In order to secure the best gripping effect with a 
 comparatively light die, it is necessary to make this form of 
 die considerably longer than those used in the other types 
 
 FIG. 209. Welding Pipe Coils. 
 
 of horizontal-acting clamps. Moreover, since there is not 
 enough space in. the narrow block to which the die is bolted 
 to permit water circulation, the die itself must be water-cooled 
 to prevent softening of the copper from continued contact with 
 the hot pipe just in back of the weld. 
 
 This type of clamp, Fig. 210, is designed for welding of 
 pipe and tubing only, which requires a much lighter pressure 
 to push up than solid stock of the same cross-sectional area, 
 and since the line of weld is considerably above the line of 
 pressure, the slides will be quickly worn on the movable platen 
 if heavy pressure is used continually. For this reason the 
 
BUTT-WELDING MACHINES AND WORK 257 
 
 FIG. 210. Clamp Used for Pipe Welding. 
 
 Fie. 211. Winfield Portable Butt-Welding Machine. 
 
258 
 
 ELECTRIC WELDING 
 
 
 
 
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BUTT-WELDING MACHINES AND WORK 
 
 259 
 
 welding of any solid stock with this class of machine is not 
 advisable. 
 
 The machine shown will weld iron and steel pipe from f 
 to 2 in. in diameter, ordinary pipe sizes and 1J in. extra heavy 
 pipe, or double heavy 1 in. in diameter. Standard steel tubing 
 
 FIG. 212. A General Purpose Butt- Welding Machine. 
 
 from 1 to 2J in. diameter may be welded. Pressure is supplied 
 by a hydraulic oil jack exerting a maximum of 5 tons. The 
 standard ratings are 30 kw. or 50 kva., with power factor of 
 60 per cent. The machine will weigh about 2,500 pounds. 
 For welding pipe, Table XXI will be found useful for 
 
260 ELECTRIC WELDING 
 
 reference purposes. This table was compiled by the Thomson 
 Electric Welding Co., with special reference to their machines. 
 
 Winfield Butt-Welding Machines. The Winfield Electric 
 Welding Machine Co., Winfield, Ohio, makes a complete line 
 of butt-welding machines but only a few representative of 
 their line, will be shown. A very convenient portable or bench 
 type is shown in Fig. 211. This is especially useful for light 
 manufacturing work. It has a capacity of 18 to 6 gage wire. 
 It is equipped with a 1 kw. transformer, hand clamping levers 
 and a 3-step self-contained regulator for controlling the cur- 
 rent. It occupies a floor space of 13^X16 in., is 35 in. high 
 from floor to center of welding dies, and weighs about 130 Ib. 
 complete. 
 
 The machine shown in Fig. 212 is for general all-round 
 shop work. It has a capacity of from j to 1 in. round, or 
 gX2 in. flat stock. It has a 25-kw. transformer, water-cooled 
 welding jaws, enclosed non-automatic switch on upsetting lever, 
 stop for regulating amount of take-up on each weld, ten-step 
 self-contained regulator for controlling the current, occupies 
 a floor space of 44X25 in., is 42 in. high to center of jaws and 
 weighs about 1,800 Ib. The jaws overhang as shown, for 
 welding hoops, rings, rims, etc. 
 
 The machine shown in Fig. 213 is for toolroom work and 
 was especially designed for handling large cross-sections. It 
 will weld up to 2-| in. round. All clamping and upsetting 
 operations are accomplished by means of air or hydraulic pres- 
 sure. The clamping cylinders are operated independently of 
 each other by means of separate valves, which enable the 
 operator to clamp each piece before the current is turned on. 
 The small air cylinder on the right-hand end of the machine 
 keeps the work in close contact during the heating operation. 
 The final pressure is applied by the hydraulic ram after the 
 proper welding heat has been attained. The table at the left 
 is equipped with adjustments for moving it up or down, back 
 and forth, tilting or twisting. This feature is especially valu- 
 able in experimental work and often saves buying a special 
 machine for unusual manufacturing jobs. The terminals are 
 cooled by a stream of water which flows from one to the other. 
 The dies are held in place by slotted clamps which permit easy 
 removal. Work stops and stops to regulate the amount of 
 
BUTT-WELDING MACHINES AND WORK 
 
 261 
 
 upset are provided. The movable table is fitted with roller 
 bearings to insure easy operation. The transformer is a Win- 
 field 125 kw. The machine has a ten-step current regulator, 
 and the current for welding is controlled by a Cutler-Hammer 
 magnetic switch which in turn is operated by means of a 
 small auxiliary switch placed on the valve lever controlling 
 the hydraulic ram. The floor space occupied is 60X90 in., and 
 the approximate weight, ready for shipment, is 8,000 Ib. 
 
 FIG. 213. Winfield Toolroom Machine. 
 
 Table XXII compiled by this concern contains some useful 
 data not given in the other tables. 
 
 Federal Butt- Welding Machines. The machines built by 
 the Federal Machine and Welder Co., Warren, Ohio, do not 
 differ in the principles of operation from the machines already 
 described. The form of the one shown in Fig. 214, however, 
 differs considerably from any shown. The tables, or platens, 
 are flat and are T-slotted so that various fixtures may be easily 
 bolted in place. The maximum capacity for continuous service, 
 is 2J in. round or other shape of equal section. Flats up to 
 
262 
 
 ELECTRIC WELDING 
 
 X10 in. may be welded. The platens are of gunmctal and 
 the T-slots will take J-in. bolts. These platens are recessed and 
 water-cooled. Pressure is applied by means of an hydraulic 
 jack, shown at the right. The switch is remote control mag- 
 netically operated. The main switch is controlled by a small 
 shunt switcli which is worked either by hand or foot, as desired. 
 The transformer is 100 kva. It has an eight-step regulating 
 coil. Floor space occupied is 38X88 in., height 50 in., weight 
 5,600 Ib. This machine is intended to weld auto-rims, heavy 
 forgings, steel frames, shafting, high-speed steel and work 
 
 FIG. 214. Federal Heavy-Duty Butt- Weld ing Machine. 
 
 requiring accurate alignment and rapid production in quan- 
 tities. 
 
 A set consisting of a tube welder and roller is shown 
 in Fig. 215. This will weld tubes from 1J to 3 in. It will 
 also weld flat, round or square stock of equivalent cross section. 
 The dies are water-cooled, and the work is clamped in position 
 by air cylinders operating on a line pressure of 80 to 100 Ib. 
 The switch is on the main operating lever, so that the heat 
 is at all times under the control of the operator. The trans- 
 former is 65 kw. air cooled. Eight current steps are obtained. 
 The machine occupies a floor space of 30X51 in., is 42 in. high, 
 and weighs 2,100 Ib. By using the set, a tube may be welded 
 and immediately transferred to the rolling machine and the 
 
BUTT-WELDING MACHINES AND WORK 
 
 263 
 
 TABLE XXII. COST OF J TO 2 IN. WELDS PER THOUSAND 
 
 
 Area in 
 
 
 
 Time 
 
 Cost Per 
 
 Average 
 
 Labor 
 Cost 
 
 Diameter 
 of Stock 
 
 Square 
 Inches 
 
 K. W. 
 
 Required 
 
 Horse 
 Power 
 
 in Sec. 1000 Welds 
 Per at 1 c. Per 
 Weld K.W. Hour 
 
 No. Per JOOO 
 of Welds at 30c. 
 Per Hour Per Hour 
 
 y 4 Inch 
 
 .05 
 
 2 
 
 3 
 
 3 
 
 .02 
 
 400 
 
 .75 
 
 5 / I ( 
 
 .08 
 
 3 
 
 4 
 
 4.5 
 
 .05 
 
 375 
 
 .80 
 
 3/ a 
 
 .11 
 
 4 
 
 5 
 
 6 
 
 .07 
 
 350 
 
 .85 
 
 Vw " 
 
 .15 
 
 5 
 
 7 
 
 6.5 
 
 .10 
 
 300 
 
 1.00 
 
 
 .20 
 
 6 
 
 8 
 
 7 
 
 .12 
 
 250 
 
 1.20 
 
 Vie ' ' 
 
 .25 
 
 7 
 
 9 
 
 7.5 
 
 .15 
 
 200 
 
 1.50 
 
 5 A " 
 
 .31 
 
 8 
 
 11 
 
 8 
 
 .18 
 
 150 
 
 2.00 
 
 
 .37 
 
 9 
 
 12 
 
 9 
 
 .23 
 
 130 
 
 2.30 
 
 3 /r " 
 
 .44 
 
 10 
 
 13 
 
 10 
 
 .28 
 
 100 
 
 3.00 
 
 13 / < < 
 
 .52 
 
 10.5 
 
 14 
 
 12 
 
 .35 
 
 95 
 
 3.20 
 
 jA 6 ;| 
 
 .60 
 
 11 
 
 15 
 
 15 
 
 .46 
 
 90 
 
 3.30 
 
 
 .69 
 
 11.5 
 
 15.5 
 
 17 
 
 .55 
 
 85 
 
 3.50 
 
 i 3 " 
 
 .79 
 
 12 
 
 16 
 
 18 
 
 .60 
 
 80 
 
 3.70 
 
 r/ s " 
 
 .99 
 
 16 
 
 21 
 
 20 
 
 .89 
 
 75 
 
 4.00 
 
 iy! ;; 
 
 1.23 
 
 19 
 
 25 
 
 25 
 
 1.32 
 
 70 
 
 4.30 
 
 
 1.48 
 
 25 
 
 33 
 
 30 
 
 2.08 
 
 65 
 
 4.60 
 
 1 V 2 ' ' 
 
 1.77 
 
 31 
 
 41 
 
 35 
 
 3.00 
 
 60 
 
 5.00 
 
 i 5 A " 
 
 2.07 
 
 38 
 
 51 
 
 37 
 
 3.90 
 
 55 
 
 5.50 
 
 i 3 / " 
 
 2.41 
 
 45 
 
 60 
 
 40 
 
 5.00 
 
 48 
 
 6.20 
 
 1 7 / < < 
 
 2.76 
 
 53 
 
 71 
 
 43 
 
 6.34 
 
 40 
 
 7.50 
 
 2 ' ' 
 
 3.14 
 
 60 
 
 80 
 
 45 
 
 7.50 
 
 30 
 
 10.00 
 
 flash rolled out. The time consumed in rolling down the flash 
 on a 2|-in. tube is given as approximately 20 seconds. 
 
 FIG. 215. A Tube-Welding Set. 
 
 Welding Rotor Bars to End Rings. In the General Electric 
 Review for December, 1918, E. F. Collins and W. Jacob describe 
 
264 ELECTRIC WELDING 
 
 the welding of rotor bars to the end rings used in squirrel-cage 
 induction motors, employing the machine shown in Fig. 216. 
 This machine has a double set of welding jaws, the front set 
 being used to butt-weld end rings to make them seamless, 
 while the rear set is used to weld the rotor bars to the end 
 rings. As shown, the machine is welding rotor-bars to the 
 end-rings. The description of the work as carried out in the 
 General Electric shops is as follows : 
 
 "The projecting rotor bars surround a toothed end ring, 
 
 FlG. 216 General Electric Machine for Eotor Work. 
 
 which is of slightly smaller diameter than the rotor. A small 
 block of copper is placed so that it covers the copper end 
 surfaces of a rotor bar and the corresponding tooth on the 
 end ring, after which it is butt-welded into place. 
 
 The projecting rotor bars are shown at A in Fig. 217 and 
 the toothed end ring just inside the circle of rotor bars is 
 shown at B. Finished welds as at C show blocks in place. 
 The actual operation is as follows: A rotor bar is tightly 
 clamped to the corresponding tooth of the end-ring between 
 the jaws D and E, The copper-block end-connection is placed 
 
BUTT-WELDING MACHINES AND WORK 
 
 265 
 
 so that it covers the combined area of tooth and bar ends. 
 The movable jaw F holds the end connection in place, and 
 heavy pressure is then applied through compression springs. 
 The welding current, furnished by a special transformer having 
 a one-turn secondary, passes from jaw F through the surfaces 
 and out through jaw E. This heavy current at low voltage 
 causes intense heating due to the comparatively high resistance 
 
 FlG. 217. Details of the Welding Mechanism and Work. 
 
 at the surface junction, and raises the temperature of the 
 copper to welding heat, at which point the metal is plastic. 
 
 At this stage spring pressure forces the jaw F toward the 
 rotor and squeezes out any oxide which may have formed 
 between the welding surfaces. A small stream of water, play- 
 ing upon the hot area, forms an atmosphere of super-heated 
 steam which prevents the formation of oxide and also guards 
 against excessive heating of the copper. No flux is used in 
 the operation as the mechanical squeezing-out of the oxide 
 
266 ELECTRIC WELDING 
 
 is sufficient to form a homogeneous connection between the two 
 surfaces. 
 
 As the welding jaws approach one another when the metal 
 becomes plastic, an electrical connection is automatically made 
 which operates a solenoid-controlled switch that opens the 
 primary transformer circuit. Thus the current is interrupted 
 as soon as the surfaces have knitted together. The contacts 
 of this automatic switch are placed one on each movable jaw, 
 and are so adjusted that they are separated by the distance 
 necessary for the jaws to approach one another in forming 
 
 FIG. 218. Butt- Welding the End Eings. 
 
 the weld and in forcing out the oxide. In this way, the end 
 connection is butt- welded to the rotor bar and the end ring, 
 forming a junction of great mechanical strength and low 
 resistance. 
 
 Another example of non-ferrous butt welding is the making 
 of seamless end rings, which operation is performed in the 
 same machine. The operation is shown in detail in Fig. 218, 
 which shows a finished end ring in place. One end of the 
 ring is placed in the vise-jaws G and H, and the other is held 
 in the opposite jaws / and J. As the jaws approach pressure 
 is applied by means of the springs. In all other respects the 
 operation is similar to that of welding the end connections. 
 
BUTT-WELDING MACHINES AND WORK 
 
 267 
 
 Rotors up to 14 ft. in diameter are welded and Fig. 219 
 shows the rotor for a 1,400-hp. motor being welded. 
 
 The work is done rapidly; for example, end connections 
 with a welding surface of about 0.6 by 0.4 in. are welded at 
 the rate of about 90 an hour. 
 
 Welding Brass. Brass rotor bars and end rings are also 
 butt-welded in a similar manner, but the operation is slower. 
 Brass, being an alloy, has a lower melting point than copper, 
 
 FIG. 219. Welding End Eing and Kotor Bars for 1400-H.P. Motor. 
 
 and less pressure is necessary to effect a weld. The pressure 
 is determined by the thickness of the piece to be welded, and 
 should be just enough to form a small " flash" at the point 
 of union. Excessive pressure will cause the molten metal to 
 spurt out from the point of weld. In one fundamental 
 particular the butt-welding of brass differs from that of copper, 
 the pressure on brass must not be released after the stoppage 
 of current until the metal has hardened sufficiently so that it 
 will not crack on cooling. This delay retards the rate of 
 welding to the extent that about 60 brass end connections. 
 
268 
 
 ELECTRIC WELDING 
 
 of the size previously mentioned, require the same time as 
 90 of copper. 
 
 Butt-welding has been the means of producing a rotor hav- 
 ing low resistance, high mechanical strength, and ability to 
 permanently withstand vibration and centrifugal force without 
 excessive heating, all of which are essential factors in an 
 efficiently operated squirrel-cage induction motor. 
 
 WELDING ELBOWS ON LIBERTY CYLINDERS 
 
 In making Liberty motors in the Ford shop, the valve 
 elbows were butt-welded on as shown in Fig. 220. The holding 
 
 FlG. 220. Welding Valve Elbows. 
 
 fixture is shown with the hinged top thrown back and a 
 cylinder in the cradle. One elbow has already been welded 
 on, and the other is held in the jaws of the sliding fixture, 
 ready to be welded in place. This work was done before 
 the cylinders were finish bored and by so doing all cylinder 
 distortion, due to welding was cut out in the finish boring. 
 
 An automatic straight-link chain making machine, built by 
 the Automatic Machine Co., Bridgeport, Conn., is shown in 
 
BUTT-WELDING MACHINES AND WORK 
 
 269 
 
 Fig. 221. This machine took the material from a reel, shown 
 at the right, formed it, butt-welded the ends of the links and 
 turned out the chain as indicated. The machine was so made 
 that the welded part of each link was pressed between special 
 dies while still hot, the operation practically eliminating the 
 
 FIG. 221. Automatic Chain Making Machine. 
 
 flash formed in welding. Aside from the welding features, the 
 machine was a marvel of mechanical ingenuity and simplicity. 
 
 ELECTRO-PERCUSSIVE WELDING 
 
 The joining of small aluminum wires has always presented 
 much difficulty on account of the oxide film which prevents 
 the metal parts from flowing together, unless brought to a 
 point of fluidity at which the oxide film can be broken up 
 and washed away. If this be attempted with small sections, 
 the whole mass is likely to be oxidized, and the resulting joint 
 will be brittle or "crumbly." 
 
 In 1905 L. "W. Chubb, of the Westinghouse Electric and 
 Manufacturing Co., Pittsburgh, Penn., discovered that if two 
 
270 
 
 ELECTRIC WELDING 
 
 pieces of wire were connected to the terminals of a charged 
 condenser, and then brought together with some force, that 
 enough electrical energy would be concentrated at the point 
 
 FlO. 222. Electro-Percussive Welding Machine. 
 
 of contact to melt the wires, while the force of the blow 
 would weld them together. Accordingly, a welding process 
 was developed and used by the Westinghouse company, and 
 
BUTT-WELDING MACHINES AND WORK 
 
 271 
 
 machines made which are capable of welding all kinds of wire 
 up to No. 13 gage. The process was called electro-percussive 
 
 FIG. 223. Details of Percussive Welding Machine and Wiring Diagram. 
 
 welding and a machine for doing the work is shown in Fig. 
 222. This machine has vertical guides A between which travels 
 
272 ELECTRIC WELDING 
 
 a chuck B holding one wire C. The other wire is held below 
 in chuck D in such a position that the end of the moving wire 
 strikes it squarely. Each chuck is connected by flexible cable 
 to a circuit as shown in Fig. 223. An electrolyte condenser 
 A, shown in the wiring diagram, is connected across a source 
 of direct current from B, which charges it to a potential 
 determined by the resistances C and D. A switch E 
 keeps the chucks F and G at the same potential during place- 
 ment and removal of work. 
 
 After the wires to be welded have been chucked, they are 
 clipped short by a cutter which gives each a chisel, or wedge- 
 shaped end. These ends are set at right angles to each other. 
 The switch is opened and the sliding chuck is released and 
 allowed to fall. At the instant when the two narrow edges 
 come into contact, the current discharged generates intense 
 heat at the center of the section. The metal melts and is 
 forced out by the impact and eventually the entire surface 
 of each wire is melted. Due to the very large body of cold 
 metal adjacent, the thin film of molten metal solidifies quickly 
 and since it is under momentarily heavy pressure it forms a 
 homogenous mass absolutely continuous with the wires on 
 each side. In practical operation, the inductance H is required 
 to lower the rate at which the condenser discharges, that is, 
 to maintain the current at a lower rate until the entire surface 
 of the weld has been forced into contact. The correct action 
 can be told by the sound made by the contact. It should be 
 a splash or thud, rather than a sharp crack. The mass and 
 drop of the falling part must be great enough to slightly forge 
 the material. Once set for the proper drop, the machine will 
 make a perfect weld every time. 
 
 Actual tests on two No. 18 B. & S. aluminum wires, using 
 an oscillograph, show that the power being expended at the 
 weld reaches a value of 23 kw. for an instant. However, the 
 entire weld is made in 0.0012 sec., and the total energy used 
 at the weld is 0.00000123 kw.-hr. The cost of this weld, figured 
 at 10 cents per kw.-hr., would be twelve millionths of a cent. 
 
 A chart of the oscillograph aluminum-wire test just referred 
 to, is shown in Fig. 224. At A the right-angled chisel-ends 
 are shown almost in contact as the upper chuck falls. As the 
 ends contact at B the voltage drops as indicated by the curve 
 
BUTT-WELDING MACHINES AND WORK 
 
 273 
 
 G, but the current and power consumption suddenly increases 
 as shown by the curves H and / respectively. 
 
 At C the wire ends have separated, caused by the melting 
 and vaporizing of the chisel edges. At D the chucks are closer 
 together but the arc is still burning away the wire ends. At 
 E the second contact has been made, the arc eliminated and 
 upsetting begun. At F the weld is shown completed. 
 
 One of the principal uses for this process is in welding 
 copper to aluminum, as for example copper lead-wires to 
 
 I 
 
 BCD E F 
 
 FIG. 224. Chart of Oscillograph Test on 18 B. & S. Gage Aluminum Wire, 
 Showing Power Consumed and Time to Complete a Percussive Weld. 
 
 aluminum coils. The advantage of copper for connecting is 
 self-evident, as it is easily soldered. It was thought at first 
 that a weld of the two metals would result in a brittle joint, 
 but tests show that after several years the joint is apparently 
 as strong and ductile as when first made. Similar ductility 
 has been noted in almost every combination of metals when 
 first welded, but disintegration and loss of ductility eventually 
 result in such welds as silver to tin or aluminum to tin, the 
 welds being affected by what is known as "tin disease " or 
 "tin pest" a disintegration of the molecules. 
 
274 
 
 ELECTRIC WELDING 
 
 Alloy of practically any composition can be welded to each 
 other, and there is little diffusion of one metal into the other 
 across the welded surface. Thus this method is quite suitable 
 
 f?C 
 
 FIG. 225. Copper Welded to Aluminum. 
 
 for attacking contact points to flat plates and making small 
 welds required by jewelers. 
 
 Another important quality of the process is that metals 
 which soften with heating, such as hard-drawn copper and 
 
BUTT-WELDING MACHINES AND WORK 275 
 
 silver, can be welded without change of condition since the 
 length of metal heated to an annealing temperature will not 
 be more than 0.004 in. long and this amount of metal is neg- 
 ligibly small. As will be seen from the specimens in Fig. 225, 
 which show copper welded to aluminum, then drawn and rolled, 
 there is no loss of ductility at the weld and no tendency for 
 the two metals to separate. 
 
CHAPTER XIII 
 SPOT- WELDING MACHINES AND WORK 
 
 Spot welding, as the name indicates, is simply welding in 
 spots. Two or more overlapping metal plates or sheets may 
 be welded together at intervals, by confining electric current 
 to a small area of passage by means of suitable electrodes, 
 or "dies" which are pressed against the metal from opposite 
 sides. Spot welding is a form of resistance welding. Due to 
 the way the metal is heated and forced together no oxidizing 
 takes place, and in consequence no flux of any kind is needed. 
 
 While the process of spot welding is more commonly used 
 at present for welding thin sheet iron, steel or brass articles, 
 practical machines have been made for welding two pieces 
 of J-in. ship plate together. Experimental machines have also 
 been made capable of spot-welding three 1-in. plates together, 
 and which can exert a pressure of 36 tons and have a current 
 capacity of 100,000 amperes. 
 
 To weld soft cold-rolled steel in a satisfactory commercial 
 manner, three conditions should be observed, if possible: 
 
 First, the surfaces to be welded should be free from rust, 
 scale or dirt. If the work is not clean a higher secondary 
 voltage will be required to penetrate through the scale or dirt 
 of any given thickness of sheet. This means that a larger 
 machine and more current must be used than would be required 
 for clean stock of the same thickness. 
 
 Second, the sheets should be flat and in good contact at 
 the spots to be welded, so that no great pressure is required 
 to flatten down bulges or dents. 
 
 Third, the stock should not surround the lower horn, as 
 in the case of welding the side seam of a can or pipe. 
 
 It must not be understood that spot welding cannot be done 
 except under the conditions outlined, for it can, but if the 
 conditions named are not followed the cost of welding will 
 be greater. However, it is often necessary to violate these 
 
 276 
 
SPOT-WELDING MACHINES AND WORK 277 
 
 conditions in actual manufacturing work. This is especially 
 true of the third one. Where the lower horn must be sur- 
 rounded by the work, as in welding can seams, the capacity 
 of the machine is cut down because of the "induction effect' 7 
 which tends to choke back the main current arid in this way 
 cuts down the heating effect at the die points. This so-called 
 induction effect is only present when welding steel or iron, 
 no such action being noticeable in welding brass. 
 
 Light gages of sheet metal can be welded to heavy gages 
 or to solid bars of steel if the light-gage metal is not greater 
 than the rated single sheet capacity of the machine. Soft steel 
 and iron form the best welding material in sheet metals, al- 
 though it is possible to weld sheet iron or steel to malleable-iron 
 castings of a good quality. 
 
 Galvanized iron can also be welded successfully, although 
 it takes a slightly longer time than clear iron or steel stock, 
 in order to burn off the zinc coating before the weld can be 
 made. Contrary to common opinion, the metal at the point 
 of weld is not made susceptible to rust by this burning off 
 of zinc, since by some electrochemical action it has been found 
 that the spots directly under each die-point and also around 
 the point of weld between the sheets, are covered with a thin 
 coating of zinc oxide after the weld has taken place. This 
 coating acts as a rust preventive to a very noticeable degree. 
 On spot-welded articles used in practice for some time, such 
 as galvanized road-culverts, refrigerator-racks and pans, rain- 
 gutters, etc., it has been found that no trace of rust has ap- 
 peared on the spot-welds from their exposure to ordinary 
 atmospheric conditions. Extra light gages of galvanized iron 
 below 28 B. & S. gage cannot be very successfully welded, due 
 to the fact that so little of the iron is left after the zinc has 
 been burnt off that the metal is very apt to burn through 
 and leave a hole in the sheets. 
 
 Tinned sheet iron is ideal for welding, giving great strength 
 at the weld, but the stock will be discolored over the area 
 covered by the die-points. Sheet brass can be welded to brass 
 or steel if it contains not more than 60 per cent copper. It 
 is not practical to attempt to spot-weld any bronze or alloy 
 containing a higher percentage of copper than this as the weld 
 will be weak. 
 
278 
 
 ELECTRIC WELDING 
 
 Another class of work that can be successfully handled on 
 a spot-welding machine, although it is not strictly spot welding, 
 is the construction of wire-goods articles. This consists prin- 
 cipally in "mash- welding" crossed wires. It may be done 
 with the same copper die-points as are used for ordinary spot 
 welding, except that the points are usually grooved to hold 
 the wire in the required position. Among the common wire 
 goods put together in this way are lamp-shade frames, oven 
 
 FIG. 226. Typical Construction of Light Spot-Welding Machine. 
 
 racks, dish drainers, waste baskets, frames for floral make-ups 
 and so on. Certain classes of butt-welding may also be done 
 on a spot-welding machine by using special attachments. 
 
 Details of Standard Spot- Welding Machines. Spot-welding 
 machines are made in various sizes and designs to meet dif- 
 ferent requirements, but the general principle of action is the 
 same in all. The illustration, Fig. 226, shows a Thomson No. 
 124-A10 machine with the cover removed. This gives an idea 
 of the principal mechanism of all this line of light spot-welding 
 
SPOT-WELDING MACHINES AND WORK 
 
 279 
 
 machines. Fig. 227 shows a typical head of one of their line 
 of heavier machines. This type of machine is designed for 
 heavy work on flat sheets or pieces, where considerable pres- 
 sure is required to bring the parts together to be welded. To 
 withstand heavy pressures, the lower horn is made of T-section 
 cast iron and the current is conducted to the lower copper 
 die-holder by flexible copper laminations, protected on all sizes 
 
 SWITCH ON COMPRESSION LEVER TO BE U5EO WHEN AUTOMATIC 
 SWITCH IS CUT OUT ff MOPE THAN 500 LB5. 15 OE5IRED 
 
 COMPRESSION LEVER REMAINS IN UPPER 
 POSITION WHEN U5ING FOOT TREADLE 
 
 COMPRESSION LEVER COUNTER 
 """ 6ALANCE WEIGHT 
 
 10 POINT SELF CON- 
 TAINED REGULATOR 
 
 TOGGLE LINK COMPRESSION 
 5WIVEL HEAD 
 
 PIN IN THIS SLOT CUTS 
 OUT AUTOMATIC SWITCH 
 
 PIN FOR FASTENING HEAD 
 ff FOOT TREADLE TOGETHER. 
 
 AUTOMATIC SOLENOID CONTROL SWITCH -~ 
 
 5CREW REGULATING AMOUNT - 
 OF TIME CURRENT IS ON 
 
 DIE BLOCKS SLIDE IN & OUT -'"\ 
 PRESSURE ADJUSTABLE SPRINGS 50-500 LB5 - 
 
 WATER COOLED SWIVEL DIE >'' 
 HEADS WITH INSERT POINTS 
 
 FIG. 227. Spot-Welding Machine for Heavy Work, with Parts Named. 
 
 having over 15-in. throat, by a brass cover, insulated on the 
 inside from the copper by a coating of asbestos sheet. 
 
 The sliding head of the machine which carries the upper 
 die-holder is a hollow steel plunger, sliding in a cast-iron head, 
 which bolts to the body of the machine and on which arc 
 mounted the control-switches. The pressure is applied by a 
 toggle-motion above the plunger, actuated both by a swiveled 
 hand-lever on top of the head, which may be swung into any 
 
280 ELECTRIC WELDING 
 
 position through an arc of 260 deg., and a foot-treadle at the 
 base, which also may be swung in an arc of 30 deg. This 
 enables the operator to control the machine by hand or foot 
 from any position around the front of the machine. 
 
 The current-control can be set to work automatically with 
 the downward stroke of the upper die. In this case the pres- 
 sure at the die-point is through an adjustable spring-cushion 
 in the hollow cylinder-head. The current is automatically 
 turned on after the die-points have come together on the work 
 by further downward pressure of either lever. With the ap- 
 plication of final pressure, to squeeze out any burnt metal as 
 the weld is forced together, the current is automatically turned 
 off. When working on pieces where more pressure is required 
 to bring the parts together before welding than can be effected 
 by the spring-cushion without turning on the current, it is 
 possible to set a plug in the head of the machine so that 
 direct connection is obtained from the hand-lever to the upper 
 die-point while the foot-treadle still operates through the 
 spring-cushion and with the automatic current-control. When 
 it is desired to secure maximum pressure, the plug in the 
 head can be set again so that both the hand-lever and the 
 foot-treadle give direct connection to the die-point, the current 
 being controlled by a push-buttom on the outer end of the 
 hand-lever. 
 
 The regular line of spot-welding machines of different 
 makes, operate on 110-, 220-, 440- and 550-volt, alternating cur- 
 rent. A welding machine of this kind can only be connected 
 to one phase of an a.c. circuit. The transformer must be made 
 to furnish a large volume of current, at a low voltage, to the 
 electrodes. For further transformer details, the reader is 
 referred to the article on butt-welding. 
 
 The Thomson Foot-, Automatic-, and Hand-Operated 
 Machines. The machine shown in Fig. 228 is representative 
 of the Thomson line of small, foot-operated spot-welding 
 machines. These are intended for use on light stock where 
 but little pressure is required. The die-holders are water- 
 cooled, arid the lower horn bracket allows the horn to be 
 adjusted up or down for the use of various kinds of holders. 
 The automatic switch and adjustable throw-in stop are plainlv 
 shown at the back of the machine. 
 
SPOT-WELDING MACHINES AND WORK 
 
 281 
 
 The model is made in several sizes. The first size will weld 
 from 30 to 16 B. & S. gage galvanized iron or soft steel, or 
 to 24 gage brass. It will mash-weld wire from 14 gage to 
 in. in diameter. Its throat depth is 12 in.; the lower horn 
 drop clearance is 9 in.; size is 22X45X51 in. high; net weight 
 
 FIG. 228. The Thomson Light Manufacturing Type Spot-Welding 
 
 Machine. 
 
 is 825 lb. ; full load rating is 5 kw., or 8 kva. The largest 
 machine of this particular series, will weld 26 to 7 gage, B. 
 & S., galvanized iron or soft steel, or 18 gage brass; it will 
 mash-weld 10-gage to f -in. diameter wire ; has an 18-in. depth 
 of throat; is 28X60X56 in. high; weighs 1,550 lb. and full 
 load rating is 15 kw. or 25 kva. 
 
282 
 
 ELECTRIC WELDING 
 
 On repetition work, where the operator has to work the 
 foot-treadle in rapid succession for long periods, it is very 
 tiresome. For such work, power-driven machines similar to 
 the one shown in Fig. 229 are made. These machines are sup- 
 plied either with individual motor drive or pulley drive, as 
 desired. The control is effected through the small treadle 
 shown. The regular foot-treadle is used while setting up dies, 
 
 FIG. 229. The Thomson Semi- Automatic Type Spot-Welding Machine. 
 
 etc. If the operator desires to make but one stroke, he depresses 
 the shorter treadle and immediately releases it, whereupon the 
 machine performs one cycle of operation, automatically turn- 
 ing on the current, applying the pressure, turning off the 
 current, and stopping. A \- to -J-hp. operating motor is used 
 according to the size of the machine. Otherwise the capacity 
 of the various sizes is the same as in the regular foot-operated 
 
SPOT-WELDMG MACHINES AND WORK 283 
 
 FIG. 230. A Thomson Heavy-Duty Spot- Wei ding Machine. 
 
 FIG. 231. Spot- Welding a Sheet Steel Box, 
 
284 
 
 ELECTRIC WELDING 
 
 machines. The lower horn and upper arm may be of either 
 style illustrated. 
 
 The machine shown in Fig. 230 is a hand-lever operated 
 machine, although supplied with a foot-treadle which can be 
 
 FIG. 232. Showing How the Horn and Welding Points May Be Set. 
 
 swung back out of the way when not needed. This machine 
 is typical of the Thomson designs used for the heavier run 
 of commercial work. On the various sizes, the capacity for 
 spot-welding is from 22 B. & S. gage galvanized iron or steel 
 
 FlG. 233. Welding Small Hoe Blades to the Shanks. 
 
 up to No. gage, or to 14 gage brass. Mash-welds may be 
 made on from -J- to f-in. diameter wire. The throat capacities 
 run from 15 to 51 in. and the lower horn adjustment is from 
 12 to 24 in. The smallest size is 28X62X75 in. high and the 
 
SPOT-WELDING MACHINES AND WORK 285 
 
 FiG. 234. Welding Stove Pipe Dampers. 
 
 FlG. 2b5. Mash- Welding Lamp Shade Frames. 
 
286 
 
 ELECTRIC WELDING 
 
 FlG. 236. Butt-Welding Attachment for a Spot- Welding Machine. 
 
 FlG. 237. Welding Galvanized Iron Pipe. 
 
SPOT-WELDING MACHINES AND WORK 
 
 287 
 
 largest size 28X98X75 in. high. The weights run from 2,335 
 to 3,225 and the full load ratings from 20 to 40 kw. or 35 to 
 67 kva. Various shaped horns, dies and other equipment are 
 furnished to meet special demands. 
 
 Examples of Spot- Welding Work. In connection with the 
 Thomson machines, the welding of the corners of a sheet-steel 
 box is shown in Fig. 231. The illustrations in Fig. 232 show 
 how the lower horn is raised for welding side seams and 
 dropped for welding on the bottom of a box. 
 
 The welding of small hoe blades to the shanks is shown 
 
 FIG. 238. Welding 12-Gage Iron for Guards. 
 
 in Fig. 233. These are welded at the rate of 840 per hour, 
 the shanks being bent afterward. Stove-pipe dampers are 
 welded as shown in Fig. 234, and wire lamp-shade frames are 
 mash-welded as shown in Fig. 235. Ordinary wire and sheet- 
 metal oven gratings or racks, with seven cross-wires welded 
 to the end pieces, have been made at the rate of 100 racks 
 per hour, or 1,400 mash-welds. On certain kinds of wire work, 
 it is desirable to butt-weld, and for this purpose the attach- 
 ment shown in Fig. 236 is used. In general, however, where 
 any amount of this kind of work is to be done, it is better 
 
288 
 
 ELECTRIC WELDING 
 
 to employ a regular butt-welding machine of the small pedestal 
 or bench type. 
 
 The spot-welding of galvanized ventilating pipe is shown 
 in Fig. 237, and in Fig. 238 is shown the welding of 12 gage 
 sheet steel machine guards. In this illustration the operator 
 is using the foot-treadle which leaves his hands free to 
 manipulate the work. In Fig. 239 the operator is welding 
 gas-stove parts and the foot-treadle is thrown back out of the 
 
 FIG. 239. Welding Stove Parts, Using a Swinging Bracket Support. 
 
 way. A special bracket is employed to hold the work. The 
 joints of this bracket are ball-bearing, making it very easy 
 to swing the work exactly where it is wanted to obtain the 
 spot-welds. 
 
 POINTS FOR SPOT WELDING 
 
 The form of spot-welding points shown in Fig. 240, says 
 A. A. Karcher, has been developed by the Challenge Machinery 
 Co., Grand Rapids, Mich., with gratifying results. Fig. 241 
 shows a typical weld and indicates the neatness, slight dis- 
 
SPOT-WELDING MACHINES AND WORK 289 
 
 FIG. 240. Form of Points for Spot Welding. 
 
 FIG. 241. Spot Weld Showing Slight Discoloration and Freedom from Flash. 
 
290 
 
 ELECTRIC WELDING 
 
 coloration of the metal and entire freedom from flash either 
 on the outside or between the parts. In one view the dis- 
 colorations give an erroneous impression of the existence of 
 bosses on the face of the metal, which is actually flat except 
 for the depressions at the points of the welds. 
 
 The shape of the points would lead one to expect that the 
 small projections would require a lot of attention to keep 
 them in shape. Experience shows, however, that this is not 
 the case, as the points actually lengthen slightly and occasion- 
 ally have to be filed down. 
 
 Even when a weld is made close to the edge the operation 
 is quicker and consumes less current. A little practice in 
 determining the correct amount of current to use is all there 
 is to learn in handling these points. 
 
 SIZES OF DIE-POINTS FOR LIGHT WORK 
 
 The data on the size of die-points in Fig. 242 arc given on 
 the authority of Lucien Haas, and may be considered good 
 
 Rounded 
 Points 
 
 FIG. 242. Sizes of Die Points for Light Work. 
 
 general practice. These points are intended for welding two 
 pieces of the same gage and material. 
 
 On certain kinds of heavy spot-welding work circular metal 
 disks are placed between the plates in order to localize the 
 current and to provide good contact. In other cases, projec- 
 tions are made in one or both of the plates. These latter, 
 of course, necessitate a mechanical or press operation, previous 
 
SPOT-WELDING MACHINES AND WORK 
 
 291 
 
 .Welding Preware 
 
 On Completion of Heating before 
 Welding Presiure ia Applied 
 
 After Completion by Arc Welding, 
 for Calking Purpoie 
 
 TIG. 243. The Tit or Projection Method of Welding. 
 
 FIG. 244. Winfield Sliding Horn Spot- Welding Machine. 
 
292 
 
 ELECTRIC WELDING 
 
 FIG. 245. Winfield Heavy-Duty Machine with Adjustable Table. 
 
 FlG. 246. Winfield Portable Spot- Welding Machine. 
 
SPOT-WELDING MACHINES AND WORK 
 
 293 
 
 to welding. Heavy plate work is shown in Fig. 243. At the 
 upper left are shown plates as commonly arranged for welding. 
 Next to this is a plate with a projection under the upper die- 
 
 FIG. 247. Winfield Portable Machine with Swivel Head. 
 
 point. A steel plunger is used in the lower die to give the 
 needed pressure after the metal is heated. This saves crushing 
 or distorting the soft copper. In the lower right-hand corner 
 
294 
 
 ELECTRIC WELDING 
 
 FIG. 248. Small Winfield Bench Machine. 
 
 FIG. 249. Winfield Machine with Suspended Head for Welding 
 Automobile Bodies. 
 
SPOT-WELDING MACHINES AND WORK 
 
 293 
 
 is shown a ridge or tit weld, after the seam has been arc- 
 welded. 
 
 The Winfield Machines. The machines made by the Win- 
 field Electric Welding Machine Co., Warren, Ohio, comprise 
 a varied line for every conceivable spot-welding purpose. In 
 general, Figs. 244 and 245 may be taken as typical of their 
 
 FIG. 250. Convenient Setting of Machine for Sheet Metal Work. 
 
 light and heavy spot-welding machines. Fig. 246 shows a 
 very convenient form of portable machine. In Fig. 247 is 
 shown a much heavier portable machine with swiveling head, 
 and in Fig. 248 is a small bench machine that is exceedingly 
 useful for light work. 
 
296 
 
 ELECTRIC WELDING 
 
 A very interesting machine is shown in Fig. 249. This 
 has the entire head suspended from the ceiling, so that work, 
 like the automobile body shown, may be worked under it. 
 
 FIG. 251. Federal Welding Machine with Universal Points. 
 
 This machine is in use in the plant of the Herbert Manu- 
 facturing Co., Detroit. 
 
 A good way to place a machine for some work is shown 
 in Fig. 250. This is employed in the shop of the Terrell 
 
SPOT-WELDING MACHINES AND WORK 
 
 297 
 
 Equipment Co., Grand Rapids, Mich., in the manufacture of 
 steel lockers, steel furniture and the like. 
 
 Federal Welding Machines. A feature of the spot-welding 
 machines made by the Federal Machine and Welder Co., War- 
 ren, Ohio, are the "universal" welding points used on most 
 of their output. The principle will be instantly grasped by 
 
 FIG. 252. A Few Positions of the Universal Points. 
 
 referring to Fig. 251. Some of the different positions possible 
 are shown in Fig. 252. 
 
 Another feature of these machines, is the use of the type 
 of water-cooled points shown in Fig. 253. The welding point 
 is copper and it is attached to the holder in such a way that 
 the water flows within half an inch of the actual welding 
 contact. 
 
298 
 
 ELECTRIC WELDING 
 
 In general form, size and capacities, the Federal line does 
 not differ materially from the machines already shown. 
 
 PIG. 253. Federal Water-Cooled Points. 
 
 FEDERAL ROTATABLE HEAD TWO-SPOT WELDING MACHINE 
 
 The rotatable head two-spot, air operated welding machine, 
 shown in Fig. 254, a 60-in. throat depth and is guaranteed 
 to weld from two thicknesses of 24-gage up to two thicknesses 
 
SPOT-WELDING MACHINES AND WORK 
 
 299 
 
 of 8-gage steel stock. Twelve welds per minute may be made 
 in the latter size. 
 
 The machine is built with a 4 kva. welding transformer 
 in the upper and lower rotating heads. Primaries are in 
 parallel while the secondaries are in series, so that two spot 
 welds must be made at the same time. 
 
 The welding electrodes or points are 1J in. in diameter, 
 are carried in water-cooled holders, and are so arranged that 
 
 FIG. 254. Federal Rotatable Head Two-spot Welding Machine. 
 
 welds from 3 to 8 in. apart may be made. The ends of each 
 set of welding points can be separated a maximum of 5 in. 
 The heads can be rotated through an angle of 90 deg. to permit 
 welding at different angles on the stock being handled. 
 
 Four air cylinders are used, each operating an independent 
 point. The air control is hand operated and so arranged that 
 an initial air line supply pressure of 80 Ib. will give from 
 300 to 700 Ib. pressure between the points during the heating 
 period. A second step on the air control makes it possible 
 
300 
 
 ELECTRIC WELDING 
 
 to apply 1,200 Ib. pressure between the points for the final 
 squeeze. The air is exhausted into the reverse side of the 
 cylinders to withdraw the points. The regulating transformer 
 supplies power to the welding transformer in eight voltage 
 steps. 
 
 FEDERAL AUTOMATIC SPOT-WELDER FOR CHANNELS 
 
 The machine shown in Fig. 255 was made for spot-welding 
 two rolled steel channels together to form an I-beam. It is 
 
 FIG. 255. Federal Channel Welding Machine. 
 
 capable of welding two spots at a time on two pieces of 
 material J in. thick, at the rate of 60 welds per min. The 
 two welding transformers are for 220 volts primary, and are 
 air cooled. Four copper disks are used for welding contacts. 
 These are securely bolted to bronze shafts to insure good elec- 
 trical connections. The secondaries of the welding trans- 
 formers are connected to the brass bearings of these shafts, com- 
 pleting the welding circuit. 
 
 The welding current is controlled by auto transformers 
 
SPOT-WELDING MACHINES AND WORK 
 
 301 
 
 in the primary circuit in eight equal steps from 65 per cent 
 to full line voltage. 
 
 The welding disks can be adjusted to handle from 4 to 16 
 in. channels. Simultaneous spot welds from 4 to 12 in. apart 
 may be made. A variable speed motor is used to control the 
 feeding of the work through the machine at from 25 to 60 
 ft. per min. 
 
 AUTOMATIC PULLEY WELDING MACHINE 
 
 The machine shown in Fig. 256 was made to weld the ring 
 section of pressed-metal pulleys, known as the filler, to the 
 
 FIG. 256. Automatic Electric Pulley Welder. 
 
 rim itself. This ring, or filler, not only acts as a stiffener 
 for the rim, but is the part to which the outer ends of the 
 spokes are attached. 
 
 In welding, one-half of a pulley rim is locked by means 
 of a chain-clamping device to a rotating carrier, with the filler 
 and spokes in place as shown. An adjustable mandrel on the 
 
302 
 
 ELECTRIC WELDING 
 
 carrier insures the proper distance between the center of the 
 pulley and the rim face. Duplicate welding sets operate on 
 each side of the filler, and spot weld intermittently as the work 
 is automatically indexed around. 
 
 The mechanical part of the machine is motor driven, and 
 with the work in place, the machine will properly space and 
 weld around the filler until it reaches the end, when it auto- 
 matically trips. The points are water cooled and will make 
 
 FIG. 257. Taylor Cross-Current Spot-Welding Machine. 
 
 about 60 welds per minute. These welding points can be set 
 to weld within 2^ in. of the center of the mandrel or supporting 
 shaft, and have a maximum distance adjustment of 12 in. 
 between them. The automatic indexing or feeding device is 
 so arranged that welds from to 3 in. or more apart may 
 be made. Pulleys from 12 in. up to 5 ft. in diameter may 
 be handled, all the necessary adjustments being easily and 
 quickly made to accommodate the various sizes. 
 
SPOT-WELDING MACHINES AND i^ORK 
 
 $03 
 
 This machine occupies a floor space of about 30X66 in., 
 weighs about 3,500 Ib. 
 
 The Taylor Welding Machines. While the machines made 
 by the Taylor Welder Co., Warren, Ohio, differ radically from 
 others on the market, in that they employ double electrodes 
 and cross current, the forms of the machines are about the 
 same as those previously shown. An automatic belt-driven 
 machine of the lighter type, is shown in Fig. 257. It may 
 
 FIG. 258. Taylor Heavy-Duty Machine. 
 
 be operated by the foot-treadle also when desired. This 
 machine has a capacity up to two -in. plates. The horns are 
 water-cooled and the adjustable points are locked in with a 
 wrench as shown. Fig. 258 shows a heavier type of machine. 
 This has a capacity of two j-in. plates ; overhang is 36 in. ; 
 distance between copper bands and lower horn, 6 in. ; base, 
 26x42 in.; extreme height, 72 in.; greatest opening between 
 welding points, 3 in. ; weight about 2,400 Ib. The transformer 
 is 35 kw. and there is a ten-step self-contained regulator for 
 
304 
 
 ELECTRIC WELDING 
 
 controlling the current. This firm makes other sizes and styles 
 of machines, to meet all the demands of the trade. 
 
 The general principle of the cross-current welding method 
 employed in these machines is illustrated in Fig. 259. Two 
 separate currents are caused to flow in a bias direction through 
 the material to be welded. A high heat concentration is claimed 
 for this method. In operation, the positives of two separate 
 
 CROS 
 
 ENT 
 
 SPO 
 
 ING 
 
 FIG. 259. Diagram of the Current Action in a Taylor Machine. 
 
 welding currents are on one side of the material and the 
 negatives on the other, with the co-working electrodes of each 
 set so that the current travels diagonally across. An advantage 
 claimed is that the electrodes on each side of the material 
 may be set far enough apart to allow of the insertion of some 
 hard material which will take the pressure instead of the 
 softer copper welding points. These hard dies may be operated 
 independently of the copper ones and make it possible to weld 
 
SPOT-WELDING MACHINES AND WORK 
 
 305 
 
 heavier material without crushing the copper die points, as 
 these need to be pressed together only enough to give good 
 
 FlG. 260. Automatic Hog-Ring Machine. 
 
 FIG. 261. Partial Rear View of Hog-Ring Machine. 
 
 electrical contact with the work. The process is also unique 
 in that it can be operated with a multiphase circuit without 
 
306 ELECTRIC WELDING 
 
 unbalancing the lines, whicli is not the case with any spot- 
 welding machine employing a single current. 
 
 Some Special Welding Machines. An automatic machine 
 for forming and mash-welding 11 gage wire hog rings, at the 
 
 FIG. 262. Close-Up of Front of Hog-Ring Machine. 
 
 rate of 60,000 per day, is shown in Fig. 260. This machine 
 takes wire from two reels and turns out the complete hog 
 rings. A partial rear view is shown in Fig. 261. A close-up 
 of the front of the machine, with two hog rings lying on the 
 platen, is given in Fig. 262. 
 
SPOT-WELDING MACHINES AND WORK 
 
 307 
 
 A machine in use in the punch press department of the 
 General Electric Co., Schenectady, N. Y., is shown in Fig. 263. 
 This machine welds small spacers to the iron laminations for 
 motors and generators for ventilating purposes, and hence is 
 
 FIG. 263. General Electric Space-Block Welding Machine. 
 
 called a " space-block welder." A number of these machines 
 are in use in this plant, and they are capable of welding 60 
 spots per minute when working continuously, not allowing for 
 time to shift the stock. 
 
 A combination spot- and line-welding machine, used in the 
 
308 
 
 ELECTRIC WELDING 
 
 General Electric Co.'s shops, is shown in Fig. 264. This is 
 employed for welding oil switch boxes up to -J in. thick. As 
 shown, the machine is fitted with a fixture for holding the 
 boxes while line-welding the seams. A separate fixture is put 
 
 FIG. 264. Combination Spot- and Line-Welding Machine, Set Up for 
 Line- Weld ing Can Seams. 
 
 on for spot-welding work. A seam 6 in. long can be line- 
 welded on this machine. 
 
 Another combination machine, used in the same shops, is 
 shown in Fig. 265. This machine carries both the spot- and 
 the line-welding fixtures at the same time. Fig. 266 shows 
 the machine from the line-welding side. As shown, the 
 
SPOT-WELDING MACHINES AND WORK 
 
 309 
 
 machines are ready for welding straight plates. Machines of 
 this kind should find a considerable field where it is desired 
 to tack seams before line welding them. These machines have 
 
 FIG. 265. A Combination Machine from the Spot- Weld ing Side. 
 
 a capacity of 20 kva., and will weld up to 3 / 16 in- thick, and 
 seams 18 in. long. 
 
 Line welding machines, as developed in the Schenectady 
 plant, comprise a transformer with a one turn secondary, 
 through which a heavy current is delivered at low voltage to 
 the material through the medium of a stationary jaw and roll- 
 
310 
 
 ELECTRIC WELDING 
 
 ing wheel. Both the jaw and wheel are water-cooled and 
 pressure is applied to the wheel the same as to a spot-welding 
 tip. A small revolving switch mechanically geared to the 
 driving motor and welding wheel operates a set of contactors 
 
 FIG. 266. Machine from the Line- Weld ing Side. 
 
 or solenoid switches to throw the power on onco a second, the 
 power being on f of a second, and off f of a second. The 
 mechanism is synchronized so that during the f of a second 
 the power is on, the welding wheel is rolling, and during the 
 
SPOT- WELDING MACHINES AND WORK 311 
 
 remaining f of a second the wheel is stationary under pressure 
 while the soft metal is solidifying, thus completing the weld. 
 Spot- Welding Machines for Ship Work. During the World 
 War, welding of all kinds took huge steps forward. Spot- 
 welding developed at least as much as any other kind. Writing 
 in the General Electrical Review, J. M. Weed says: 
 
 The machines to be described are two portable welders, one with 12-in. 
 reach and the other with 27-in. reach, for use in the fabrication of 
 structural ship parts, and one stationary machine with 6-ft. reach designed 
 for welding two spots at the same time on large ship plates. 
 
 A preliminary survey of the structural work in shipbuilding indicated 
 that about 80 per cent of this work could be done by a machine of 12-in. 
 reach, and that a 27-in. reach would include the other 20 per cent. Since 
 both the weight of the machine and the kva. required for its operation 
 are about 33 per cent greater for the 27-in. reach than for the 12-in., 
 it seemed advisable to develop two machines rather than one with the 
 longer reach. 
 
 These machines were to a certain obvious extent patterned after the 
 riveting machines, which they were intended to replace as will be seen 
 from Fig. 267. They are necessarily considerably heavier than the riveting 
 machines, but like these they are provided with bales for crane suspension, 
 for the purpose of carrying the machines around the assembled work or 
 parts to be welded. 
 
 The maximum welding current available- in these machines, with a steel 
 plate enclosed to the full deptn of the gap, is about 37,500 amperes, with 
 the maximum applied voltage of 534 volts at 60 cycles. Reduced voltages, 
 giving smaller currents, are obtained in six equal steps, ranging from 
 534 down to 267 volts, from the taps of the regulating transformers 
 furnished with the machines. 
 
 This wide range of voltage and current was provided in order to meet 
 the possible requirements for a considerable range in thickness of work, 
 and for experimental purposes. Tests have shown, however, that the 
 machines will operate satisfactorily on work of thicknesses over the range 
 on which they are likely to be used when connected directly on a 440-volt, 
 60-cycle circuit, with no regulating transformers. Two plates -in. thiek 
 are welded together in spots from 1 in. to 1 in. in diameter, in from 
 12 to 15 seconds. Thicker plates require more time and thinner plates 
 less time. 
 
 The welding current under these conditions is about 31,000 amp.; the 
 primary current is about 600 amp. for the 12-in. machine and about 800 
 amp. for the 27-in. machine, the corresponding kva. at 440 volts, being 
 265 and 350 respectively. 
 
 Since the reactance of the welding circuit is large as compared with 
 the resistance, the voltage necessary for a given current, and conse- 
 quently the kva. necessary for the operation of the machine, is 
 almost proportional to the frequency. Thus, these machines operate satis- 
 
312 
 
 ELECTRIC WELDING 
 
 factorily from a 25-cycle circuit at 220 volts, with the advantage that 
 where the power-factor is from 30 to 40 per cent at 60 cycles, it is from 
 60 to 75 per cent at 25 cycles, and the kva. required at 25 cycles is about 
 one-half that required at 60 cycles. 
 
 The maximum mechanical pressure on the work for which those machines 
 are designed is 25,000 Ib. This is obtained from an 8-in. air cylinder, 
 with an air pressure of 100 Ib. per square inch, acting through a lever 
 arm of 5 to 1 ratio. Lower pressures on the work are obtained with 
 
 FlG. 267. Portable Spot-Welding Machine with 27-in. Throat Depth. 
 Capable of Welding Two Plates In. Thick in Spots 1 In. in Diameter. 
 Made by the General Electric Co. 
 
 correspondingly reduced air pressures. A pressure-reducing valve is pro- 
 vided for this purpose, and also a pressure gage for indicating the pressure 
 on the machine side of the valve. 
 
 The pressure required to do satisfactory welding depends upon the 
 thickness of the plates. It is necessary that the areas to be welded should 
 at the start be brought into more intimate contact than the surrounding 
 areas, in order that the current may be properly localized, and the heat 
 
SPOT- WELDING MACHINES AND WORK 313 
 
 generated in the region where it is needed. It is therefore necessary, on 
 account of irregularities in the plate surface, that the pressure should be 
 great enough to spring the cold plate sufficiently to overcome the irregulari- 
 ties. The pressure which will do this with heavy plates is ample for 
 effecting the weld after the welding temperature is reached. 
 
 It should be explained in this connection that the rate of heating at 
 the surfaces to be welded depends largely upon the contact resistance, 
 and consequently upon the condition of the plates and the pressure used. 
 If the plates are clean and bright, and the pressure high, the rate of 
 heating with a given amount of current is slow and the welding efficiency 
 is poor. This makes it difficult to weld heavy plates if they are clean, 
 since, as stated above, it is necessary to use large pressure with heavy 
 plates to insure a better contact of the areas to be welded than that of 
 surrounding areas. It is much easier to weld plates which carry the 
 original coat of mill scale, or a fairly heavy coating of rust or dirt, 
 affording a considerable resistance which is not sensitive to pressure. If 
 this resistance is too great, the necessary current will not flow, of course, 
 but if the scale is not too heavy it has little effect upon the current, 
 the high reactance of the welding circuit giving it practically a constant 
 current characteristic and making the rate of heating proportional to the 
 resistance within certain limits. The scale melts at about the welding 
 temperature of the steel, and is squeezed out by the high pressures used, 
 permitting the clean surfaces of the steel to come together and effect 
 a good weld. 
 
 A gage pressure of about 70 lb., giving 17,500 Ib. pressure upon the 
 work, has been found to give good results under these conditions in ^-in. 
 plates. 
 
 Both the mechanical pressure and the current are transmitted to the 
 work in these machines through heavy copper blocks or welding electrodes. 
 The shape of the tips of these electrodes is that of a very flat truncated 
 cone. 
 
 The severity of the conditions to which the tips of the electrodes 
 are subjected will be understood when it is considered that the current 
 density in the electrode material at this point is approximately 60,000 
 amp. per square inch, and that this material is in contact with the steel 
 plates which are brought to the welding temperature, under pressures of 
 15,000 to 20,000 lb. per square inch. It must be remembered, also, that 
 copper, which is the best material available for this purpose, softens at 
 a temperature considerably lower than the welding temperature of steel. 
 The difficulty of making the electrode tips stand up under the conditions 
 to which they are subjected has, in fact, constituted the most serious 
 problem which has been met in the development of these machines. 
 
 The shape of these electrodes gives them every possible advantage in 
 freely conducting the current to and the heat away from the electrode 
 tips, and in giving them the mechanical reinforcement of the cooler sur- 
 rounding material. However, it has been found necessary to reduce, as 
 far as possible, the heat generated at the tips of the electrodes by cleaning 
 the rust and mill scale from the surfaces of the plates beneath the elec- 
 
314. ELECTRIC WELDING 
 
 trodes. The most convenient way which has been found for ooing this 
 is by means of a sand blast. The bodies of the electrodes are also internally 
 water-cooled by a stream of water flowing continually through them. Still, 
 after all of these things have been done, a gradual deformation of the tip 
 of the electrode will occur, increasing its area of contact with the work, 
 and thus reducing the current density in the work and the pressure density 
 below the values needed for welding. This would make it necessary to 
 change electrodes and to reshape the tips very frequently, and the total 
 life of the electrodes would be short on account of the frequent dress- 
 ings. 
 
 An effort has been made to overcome this difficulty by protecting the 
 tip of the electrode by a thin copper cap, which may be quickly and 
 cheaply replaced. As many as 160 welds have been made with a single 
 copper cap, y J6 in. thick, before it became necessary to replace it. Un- 
 fortunately this does not entirely prevent the deformation of the electrode 
 tip, but it stands up much better than it does without the cap. 
 
 Another method which has been tried for overcoming this trouble is 
 by making the tip portion of the electrode removable, in the form of a 
 disk or button, held in place by a clamp engaging in a neck or groove 
 on the electrode body. While this protects the electrode body from 
 deformation and wear, the tip itself does not stand up so well as does 
 the combination of electrode and cap, where the tip of the electrode is 
 not separated from the body. 
 
 Some electrodes have been prepared which combine the features of 
 the removable tip and cap. These give the advantage of a permanent 
 electrode body, and the removable tip with the protecting cap stand up 
 better than the unprotected tip. 
 
 Some interesting features were introduced in the design of the trans- 
 formers which are integral parts of these machines, owing to the necessity 
 for small size and weight. Internal water cooling was adopted for the 
 windings, which makes it possible to use current densities very much 
 higher than those found in ordinary power transformers. The conductor 
 for the primary windings is -in.X2'i n ' copper tubing, which was obtained 
 in standard lengths and annealed before winding by passing it through 
 an oven which is used for annealing sheathed wire during the process of 
 drawing. No difficulty was found in winding this tubing directly on the 
 insulated core, the joints between lengths being made by brazing with 
 silver solder. The entire winding consists of four layers of thirteen turns 
 each in the 12-in. machine and three layers of thirteen turns each in the 
 27-in. machine. 
 
 The U-shaped single-turn secondaries were slipped over the outside of 
 the primary windings in the assembly of the transformers. These were 
 constructed of two copper plates each in. thick and 6| in. wide, which 
 wero bent to the proper shape in the blacksmith shop, and assembled one 
 inside the other with a ^-in. space between them. Narrow strips of copper 
 were inserted between the plates along the edges, and the plates were 
 brazed to these strips, thus making a water-tight chamber or passage for 
 the circulation of the cooling water. 
 
SPOT-WELDING MACHINES AND WORK 315 
 
 At 31,000 amp. the current density in these secondaries is about 6,200 
 amp. per square inch, the corresponding densities in the primary windings 
 being about 7,000 for the 12-in. and 9,000 for the 27-in. machine. 
 
 In case these machines are started up without the cooling water having 
 been turned on, the temperature rise in these windings will be rapid, and 
 in order to avoid the danger of burning the insulation, asbestos and mica 
 have been used. The copper tubing was taped with asbestos tape, and 
 alternate layers of sheet asbestos and mica pads were used between layers 
 of the primary winding, and between primary and secondary and between 
 primary and core. Space blocks of asbestos lumber, which is a compound 
 of asbestos and Portland cement, were used at the ends of the core 
 and at the ends of the winding layers. The complete transformer, after 
 assembly, was impregnated with bakelite. The result is a solid mechanical 
 unit which will not be injured by temperatures not exceeding 150 deg. C. 
 Several welds could be made without turning on the cooling water before 
 this temperature would be reached. 
 
 The transformers are mounted on a chamber in the body of the frame. 
 The long end of the U-shaped secondary runs out along the arm of the 
 frame and bolts directly to the copper base upon which the bottom electrode 
 is mounted. The short end connects to the base of the top electrode 
 through flexible leads of laminated copper, to permit of necessary motion 
 for engaging the work. 
 
 The copper bases upon which the electrodes are mounted are insulated 
 from the frame by a layer of mica, the bolts which hold them in place 
 being also insulated by mica. 
 
 The cooling water for these machines is divided into two parallel 
 paths, one being through the primary winding, and the other through the 
 secondary and the electrodes in series. Separate valves are supplied for 
 independent adjustment of the flow in the two paths. The resistance of 
 ordinary hydrant water is sufficiently great as to cause no concern regarding 
 the grounding or short-circuiting of the windings through the cooling water, 
 although it is necessary to use rubber tubing or hose for leading it in 
 and out. 
 
 Some pieces of %y(2-in. machine steel were welded in seven seconds 
 with a current of 33,000 amp. They were afterward clamped in a vise 
 and hammered into U-shapes. Small pieces were sheared from the seam 
 where two - in. plates had been welded together in a row of spots. The 
 pieces of the plates were then split apart with a cold chisel in one case, 
 and an effort was made to do so in the other, with the result that one 
 piece of plate broke at the welds before the welds would themselves break. 
 Such tests as these show that the welds are at least as strong as the 
 material on which the welds were made. Some samples of the x2-in. 
 stock welded together in the same manner were tested by bending in an 
 edgewise direction, thus subjecting the welds to a shearing torque. The 
 ultimate strength calculated from these tests was in the neighborhood of 
 65,000 Ib. per square inch. These tests showed also a very tough weld, 
 the deflection being almost 45 deg. in some cases before the final rupture 
 occurred. The maximum load occurred with a deflection of from 3 to 5 
 
316 
 
 ELECTRIC WELDING 
 
 deg. with a very gradual reduction in the load from this time till the 
 final rupture. 
 
 The Duplex Welding Machine. The machine shown in Fig. 268 was 
 developed for the application of electric welding as a substitute for riveting 
 on parts of the ship composed of large-sized plates, which may be fabricated 
 before they are assembled in the ship. The specification to which it was 
 built stated that it should have a 6-ft. reach and should be capable of 
 welding together two plates f in. thick in two spots at the same time. 
 A machine capable of doing this work, with a 6-ft. gap, is necessarily 
 
 FIG. 268. Duplex Spot-Welding Machine. Made by the General Electric 
 Co. 6-ft. Throat Depth, and Capable of Welding Together Two Steel 
 Plates | In. Thick, in Two Spots 1 In. in Diameter. 
 
 so heavy as to preclude even semi-portability, and no effort was made in 
 this direction. 
 
 With the welding circuit enclosing a 6-ft. gap, and carrying the very 
 heavy current necessary to weld f-in. plates, the kva. required would be 
 very large. A great reduction in the kva. and at the same time a doubling 
 of the work done, is obtained in this machine by the use of two trans- 
 formers as integral parts of the machine, and two pairs of electrodes, 
 thus providing for the welding of two spots at the same time. The 
 transformers are mounted in the frame of the machine, on opposite sides 
 of the work, and as near to the welding electrodes as possible, so as to 
 
SPOT-WELDING MACHINES AND WORK 317 
 
 obtain the minimum reactance in the welding circuit. The polarity of 
 the electrodes on one side of the work is the reverse of that of the opposed 
 electrodes, thus giving a series arrangement of the transformer secondaries, 
 the current from each transformer flowing through both of the spots to 
 be welded. 
 
 The bottom electrodes are stationary, and the copper bases which bear 
 them are connected rigidly to the terminals of their transformer, while 
 the bases which carry the top electrodes are connected through flexible 
 leads of laminated copper, to permit of the motion necessary for engaging 
 the work. 
 
 Previous tests with an experimental machine had shown that, to suc- 
 cessfully weld two spots at the same time in the manner adopted here, 
 it is necessary that the pressures shall be independently applied. Otherwise, 
 due to inequalities in the thickness of the work, or in the wear and tear 
 of the electrodes, the pressure may be much greater on one of the spots 
 than on the other. This results in unequal heating in the two spots. The 
 resistance and its heating effect are less in the spot with the greater 
 pressure. The two top electrodes in this machine were therefore mounted 
 on separate plungers, operated by separate pistons through independent 
 levers. 
 
 The pressures obtained in this machine with an air pressure of 100 
 Ib. per square inch, are 30,000 Ib. on each spot, giving a total pressure 
 of 60,000 Ib. which must be exerted by the frame around the 6-ft. gap. 
 The necessary strength is obtained by constructing the frame of two steel 
 plates, each 2 in. thick, properly spaced and rigidly bolted together. 
 
 The use of steel in this case is easily permissible on account of the 
 restricted area of the welding circuit and its relative position, resulting 
 in small tendency for magnetic flux to enter the frame. However, the 
 heads carrying the electrodes, being in close proximity to the welding 
 circuit, were made of gun metal. 
 
 The two air cylinders are mounted on a cast-iron bed-plate in the 
 back part of the machine. The levers connecting the pistons to the electrode 
 plungers, which are 7 ft. in length, were made of cast steel, in order to 
 obtain the necessary strength. 
 
 The maximum welding current for which this machine was designed is 
 50,000 amp. This current is obtained with 500 volts at 60 cycles applied. 
 
 The distance between the electrode bodies for this machine is fixed 
 at 8 in., center to center, but the distances between the centers of the 
 tips may be easily varied from 6 in. to 10 in. by shifting the tip from 
 the center of the body toward one side or the other. 
 
 Provision has been made for shifting the electrodes on their bases to 
 positions 90 deg. from those shown in the picture, thus spacing the welds 
 in a direction along the axis of the machine instead of traverse to it. 
 
 The transformers are insulated and cooled in the same manner as 
 those in "the semi-portable machines. The windings are interlaced in order 
 to obtain minimum reactance, the primary being wound in two layers of 
 14 turns each, one inside and the other outside of the single turn secondary. 
 
 With 50,000 amp. in the secondaries of these transformers, the current 
 
318 ELECTRIC WELDING 
 
 in tne primary is 1,800. The respective current densities are 7,000 and 
 9,000 amp. per square inch. The kva. entering the transformers on this 
 basis, the two primaries being in series on 500 volts, is 450 for each 
 transformer. 
 
 This machine also has been provided with a regulating transformer 
 for applying different voltages to give different values of welding current, 
 
 FIG. 269. General Electric Co.'s Experimental Spot-Welding Machine. 
 Current Capacity 100,000 Amp. Pressure Capacity 36 Tons. Has 
 Welded Three Plates, Each 1 In. Thick. 
 
 and with a panel carrying the necessary selector switches and contactor. 
 The maximum voltage provided by this regulating transformer as at 
 present constructed is 440. If it is found that the current obtained with 
 this voltage is not sufficient for the heaviest work which it is desired to 
 do with this machine, the maximum voltage may be changed to 500. 
 
 The kva. entering the transformers of 440 volts will be approximately 
 350 each, instead of 450. 
 
SPOT-WELDING MACHINES AND WORK 319 
 
 In order that this machine may be operated from any ordinary power 
 circuit, it will be necessary to use a motor-generator set provided with 
 a suitable flywheel. This will eliminate the bad power-factor, distribute 
 the load equally on the three phases, and over a much larger interval of 
 time for each weld, thus substituting small gradual changes in power for 
 large and sudden changes. On account of the high reactance the welding 
 current will remain practically Constant as the speed of the motor-generator 
 set falls away, thus favoring the utilization of the flywheel. The total 
 maximum power drawn from the circuit with this arrangement would be 
 about 100 kilowatts. 
 
 
 FIG. 270. Portable Machine for Mash- Welding Square or Bound Rods. 
 
 A Heavy Experimental Spot- Welding Machine. The 
 machine shown in Fig. 269 was built in 1918 by the General 
 Electric Co., in order to investigate the possibilities of welding 
 plates from. in. up. Three plates each 1 in. thick have been 
 welded with it. The machine is provided with a 2,000-kva. 
 transformer, having a capacity of 100,000 amp. at 20 volts. 
 Hydraulic pressures up to 36 tons are obtained at the elec- 
 trodes. Motor-generator sets of 500- and 6,000-kva. capacity 
 
320 
 
 ELECTRIC WELDING 
 
 were used. From the nature of the service, it was apparent 
 that some form of cooling was needed at the contact points. 
 It was found, however, that it was impossible to water-cool 
 the points sufficiently to give a reasonable life to the electrodes 
 if they were kept the same diameter for any distance from 
 the work. In consequence heavy masses of copper were placed 
 
 FIG. 271. Lorain Machine for Spot- Welding Electric Rail Bonds. 
 
 as close to the points of contact as practicable. By doing this 
 it was possible to have a very large cooling surface at the 
 top of the electrode and by passing water through this part 
 at the time of welding and between welds, the joints were kept 
 cool enough for all practical purposes. 
 
 A portable machine for making mash-welds for splicing or 
 attaching round or square rods cross-wise, is shown in Fig. 
 
SPOT-WELDING MACHINES AND WORK 321 
 
 270. This was made by the General Electric Co., for ship- 
 yard use. 
 
 A big machine for spot-welding electric railway bonds, is 
 shown in Fig. 271. This is made by the Lorain Steel Co., 
 Johnstown, Pa. It will weld two plates 18 in. long and 3 in. 
 wide by 1 in. thick, each plate having three raised "welding 
 bosses. ' ' Pressure as high as 35 tons is obtainable and current 
 up. to 25,000 amp. may be used. 
 
 Spot- Welding Data. It is difficult to give definite costs for 
 spot welding, as much depends on the operator. A careless 
 or inexperienced operator will waste more current than a good 
 one, and various conditions of the metal being worked on 
 will make a considerable difference at times. However, the 
 information given in Table XXIII, which is furnished by the 
 Winfield Electric Welding Machine Co., will prove of value 
 as a basis for calculations. Tables XXIV and XXV will also 
 be useful to use in connection with the measurement of the 
 thickness of sheets, and in comparing different gages. 
 
 TABLE XXIII. SPOT-WELDING POWER AND COST DATA 
 
 Gauge 
 Number 
 
 Thickness of 
 Sheets in 
 Fractions of 
 an Inch 
 
 Thickness of 
 Sheets in 
 Decimals of 
 an Inch 
 
 K. w. 
 
 Required 
 
 H. P. 
 
 Required 
 
 Time in 
 Seconds 
 to Make 
 a Weld 
 
 Cost 1000 
 Welds at one 
 Cent per 
 K. W. Hour 
 
 30 
 
 Vso 
 
 .0125 
 
 3.0 
 
 4.2 
 
 -.25 
 
 .002 
 
 28 
 
 74 
 
 .0156 
 
 4.0 
 
 5.6 
 
 .3 
 
 .003 
 
 24 
 
 7*0 
 
 .0250 
 
 5.0 
 
 7.0 
 
 .45 
 
 .006 
 
 20 
 
 Vso 
 
 .0375 
 
 6.5 
 
 9.2 
 
 .6 
 
 .011 
 
 18 
 
 Yso 
 
 .0500 
 
 8.0 
 
 11.3 
 
 .8 
 
 .017 
 
 16 
 
 V* 
 
 .0626 
 
 9.5 
 
 13.5 
 
 1.0 
 
 .026 
 
 14 
 
 Ye* 
 
 .0781 
 
 10.0 
 
 14.2 
 
 1.3 
 
 .036 
 
 12 
 
 v 
 
 .1093 
 
 12.0 
 
 17.0 
 
 1.6 
 
 .052 
 
 11 
 
 % 
 
 .1250 
 
 13.0 
 
 18.5 
 
 1.7 
 
 .061 
 
 10 
 
 Ye* 
 
 .1406 
 
 14.0 
 
 19.9 
 
 1.8 
 
 .070 
 
 9 
 
 Ya 2 
 
 . .1562 
 
 15.0 
 
 21.3 
 
 1.9 
 
 .079 
 
 8 
 
 "/64 
 
 .1715 
 
 16.0 
 
 22.7 
 
 2.0 
 
 .088 
 
 7 
 
 Yl6 
 
 .1875 
 
 17.0 
 
 24.1 
 
 2.1 
 
 .099 
 
 6 
 
 */ m 
 
 .2031 
 
 18.0 
 
 25.6 
 
 2.2 
 
 .110 
 
 5 
 
 Y32 
 
 .2187 
 
 19.0 
 
 27.0 
 
 2.4 
 
 .124 
 
 4 
 
 M / 
 
 .2343 
 
 20.0 
 
 28.4 
 
 2.7 
 
 .148 
 
 3 
 
 % 
 
 .2500 
 
 21.0 
 
 29.8 
 
 3.0 
 
 .174 
 
 As the cost of current varies in different places, we have figured the 
 current at one cent per K. W. hour to give a basis for calculating the 
 cost. Multiply the cost of current given above by the rate per K. W. hour 
 you pay and you will have your cost per 1000 welds for current. 
 
322 
 
 ELECTRIC WELDING 
 
 <r 
 
 10 
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 10 t- 
 
 IQ 
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 *0 
 
 (X 
 
 0*0 
 
 O 
 
 I- GO CO N 00 i - t~ CO 
 COOitOOCD^t^COOO"* 
 
 CD < t 
 
 <N<N<XO>*<NCOCOGO 
 
 SSSs 
 
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SPOT-WELDING MACHINES AND WORK 
 
 323 
 
 TABLE XXV. DECIMAL EQUIVALENTS OF AN INCH FOR MILLIMETERS, 
 B. & S. AND BIRMINGHAM WIRE GAGES 
 
 Decimal 
 Inch 
 
 Mill. 
 
 Fra. 
 In. 
 
 B&S 
 
 Birm 
 Gge. 
 
 Decimal 
 Inch 
 
 Mill. 
 
 Fra. 
 In. 
 
 B&S 
 
 Birn, 
 Gge. 
 
 Decimal 
 Inch 
 
 Mill. 
 
 Fra. 
 In. 
 
 B&S 
 
 Birm 
 Gge. 
 
 .00394 
 
 .1 
 
 
 
 
 .11443 
 
 
 
 9 
 
 
 . 296875 
 
 
 It 
 
 
 
 .00787 
 
 .2 
 
 
 
 
 .11811 
 
 3.0 
 
 
 
 
 . 29921 
 
 7.6 
 
 
 
 
 .010025 
 
 
 
 30 
 
 
 .12 
 
 
 
 
 11 
 
 .3 
 
 
 
 
 1 
 
 .011257 
 
 
 
 29 
 
 
 . 12204 
 
 3.1 
 
 
 
 
 .30314 
 
 7.7 
 
 
 
 
 .01181 
 
 .3 
 
 
 
 
 .125 
 
 
 y* 
 
 
 
 .30708 
 
 7.8 
 
 
 
 
 .012 
 
 
 
 
 30 
 
 . 12598 
 
 3.2 
 
 
 
 
 .31102 
 
 7.9 
 
 
 
 
 .012641 
 
 
 
 28 
 
 
 . 12849 
 
 
 
 8 
 
 
 .3125 
 
 
 A 
 
 
 
 .013 
 
 
 
 
 29 
 
 . 12992 
 
 3.3 
 
 
 
 
 .31496 
 
 8.0 
 
 
 
 
 .014 
 
 
 
 
 28 
 
 . 13385 
 
 3.4 
 
 
 
 
 .31889 
 
 8.1 
 
 
 
 
 .014195 
 
 
 
 27 
 
 
 .134 
 
 
 
 
 10 
 
 . 32283 
 
 8.2 
 
 
 
 
 .015625 
 
 
 A 
 
 
 
 . 13779 
 
 3.5 
 
 
 
 
 . 32495 
 
 
 
 
 
 
 .01575 
 
 .4 
 
 
 
 
 . 140625 
 
 
 A 
 
 
 
 . 32677 
 
 8.3 
 
 
 
 
 .01594 
 
 
 
 26 
 
 
 .14173 
 
 3.6 
 
 
 
 
 .328125 
 
 
 ft 
 
 
 
 .016 
 
 
 
 
 27 
 
 . 14428 
 
 
 
 7 
 
 
 .3307 
 
 8.4 
 
 
 
 
 .0179 
 
 
 
 25 
 
 
 . 14566 
 
 3.7 
 
 
 
 
 .33464 
 
 8.5 
 
 
 
 
 .018 
 
 
 
 
 26 
 
 .148 
 
 
 
 
 9 
 
 . 33858 
 
 8.6 
 
 
 
 
 .01968 
 
 .5 
 
 
 
 
 . 14960 
 
 3.8 
 
 
 
 
 .34 
 
 
 
 
 
 
 .02 
 
 
 
 
 25 
 
 . 15354 
 
 3.9 
 
 
 
 
 .34251 
 
 8.7 
 
 
 
 
 .0201 
 
 
 
 24 
 
 
 . 15625 
 
 
 A 
 
 
 
 .34375 
 
 
 H 
 
 
 
 .022 
 
 
 
 
 24 
 
 . 15748 
 
 4.0 
 
 
 
 
 .34645 
 
 8.8 
 
 
 
 
 .022571 
 
 
 
 23 
 
 
 .16141 
 
 4.1 
 
 
 
 
 . 35039 
 
 8.9 
 
 
 
 
 .02362 
 
 .6 
 
 
 
 
 . 16202 
 
 
 
 6 
 
 
 . 35433 
 
 9.0 
 
 
 
 
 .025 
 
 
 
 
 23 
 
 .165 
 
 
 
 
 8 
 
 . 35826 
 
 9.1 
 
 
 
 
 .025347 
 
 
 
 22 
 
 
 .16535 
 
 4.2 
 
 
 
 
 .359375 
 
 
 11 
 
 
 
 .02756 
 
 .7 
 
 
 
 
 . 16929 
 
 4.3 
 
 
 
 
 . 36220 
 
 9.2 
 
 
 
 
 .028 
 
 
 
 
 22 
 
 .171875 
 
 
 ti 
 
 
 
 .3648 
 
 
 
 
 00 
 
 . 02846 
 
 
 
 21 
 
 
 . 17322 
 
 4.4 
 
 
 
 
 .36614 
 
 9.3 
 
 
 
 
 .03125 
 
 
 & 
 
 
 
 .17716 
 
 4.5 
 
 
 
 
 . 37007 
 
 9.4 
 
 
 
 
 .03149 
 
 .8 
 
 
 
 
 .180 
 
 
 
 
 7 
 
 .37401 
 
 9.5 
 
 
 
 
 .03196 
 
 
 
 20 
 
 
 .1811 
 
 4.6 
 
 
 
 
 .375 
 
 
 3 A 
 
 
 
 .032 
 
 
 
 
 21 
 
 . 18194 
 
 
 
 5 
 
 
 . 37795 
 
 9.6 
 
 
 
 
 .035 
 
 
 
 
 20 
 
 . 18503 
 
 4.7 
 
 
 
 
 .38 
 
 
 
 
 00 
 
 . 03543 
 
 .9 
 
 
 
 
 .1875 
 
 
 A 
 
 
 
 .38188 
 
 9.7 
 
 
 
 
 .03589 
 
 
 
 19 
 
 
 . 18897 
 
 4.8 
 
 
 
 
 . 38582 
 
 9.8 
 
 
 
 
 . 03937 
 
 1.0 
 
 
 
 
 .19291 
 
 4.9 
 
 
 
 
 .38976 
 
 9.9 
 
 
 
 
 .04030 
 
 
 
 18 
 
 
 . 19685 
 
 5.0 
 
 
 
 
 . 390625 
 
 
 H 
 
 
 
 .042 
 
 
 
 
 19 
 
 . 20078 
 
 5.1 
 
 
 
 
 .3937 
 
 10.0 
 
 
 
 
 .0433 
 
 1.1 
 
 
 
 
 .203 
 
 
 
 
 6 
 
 . 39763 
 
 10.1 
 
 
 
 
 .04525 
 
 
 
 17 
 
 
 .203125 
 
 
 if 
 
 
 
 .40157 
 
 10.2 
 
 
 
 
 . 46875 
 
 
 A 
 
 
 
 .20431 
 
 
 
 4 
 
 
 .40551 
 
 10.3 
 
 
 
 
 .04724 
 
 1.2 
 
 
 
 
 . 20472 
 
 5.2 
 
 
 
 
 . 40625 
 
 
 M 
 
 
 
 .049 
 
 
 
 
 18 
 
 . 20866 
 
 5.3 
 
 
 
 
 .40499 
 
 10.4 
 
 
 
 
 .05082 
 
 
 
 16 
 
 
 .21259 
 
 5.4 
 
 
 
 
 .4096 
 
 
 
 000 
 
 
 .05118 
 
 1.3 
 
 
 
 
 .21653 
 
 5.5 
 
 
 
 
 .41338 
 
 10.5 
 
 
 
 
 .05512 
 
 1.4 
 
 
 
 
 .21875 
 
 
 A 
 
 
 
 .41732 
 
 10.6 
 
 
 
 
 . 05706 
 
 
 
 15 
 
 
 .22 
 
 
 
 
 5 
 
 .42125 
 
 10.7 
 
 
 
 
 .058 
 
 
 
 
 17 
 
 .22047 
 
 5.6 
 
 
 
 
 .421875 
 
 
 11 
 
 
 
 .05905 
 
 1.5 
 
 
 
 
 .2244 
 
 5.7 
 
 
 
 
 .425 
 
 
 
 
 000 
 
 .0625 
 
 
 f 
 
 
 
 . 22834 
 
 5.8 
 
 
 
 
 .42519 
 
 10.8 
 
 
 
 
 . 06299 
 
 1.6 
 
 
 
 
 . 22942 
 
 
 
 3 
 
 
 .42913 
 
 10.9 
 
 
 
 
 .06408 
 
 
 
 14 
 
 
 .23228 
 
 5.9 
 
 
 
 
 .43307 
 
 11.0 
 
 
 
 
 .065 
 
 
 
 
 16 
 
 .234375 
 
 
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CHAPTER XIV 
 
 WELDING BOILER TUBES BY THE ELECTRIC 
 RESISTANCE PROCESS 
 
 About 1912 the resistance, or Thomson, process of electric 
 welding was first tried out in a locomotive shop for the purpose 
 of replacing the oil-furnace welding equipment in safe-ending 
 boiler tubes up to 2^ in. in diameter, says P. T. Van Bibber, 
 in the American Machinist. At the present time, in shops in 
 different parts of the country where electric welding machines 
 have been installed, one will find many enthusiastic " boosters" 
 for this process. It is to these users that we are indebted for 
 the information contained in this article and for the benefit 
 of those who are unfamiliar with this adaptation of resistance 
 welding, an endeavor has been made to cover all the details 
 possible. 
 
 In using the resistance type of machine for welding safe- 
 ends onto locomotive-boiler flues, the old tube and the new 
 safe-end are gripped securely in heavy copper jaws with the 
 ends to be joined held in alignment. As these ends are 
 pressed together a large volume of current from the secondary 
 winding of the transformer is passed through them. Since the 
 junction of the abutting ends is the point of greatest resistance 
 to the electric current, the greatest heating effect is there 
 and, usually, on a 2^-in. tube it requires only about 15 sec. 
 to secure a perfect running or welding heat. A slight push-up 
 by the pressure device on the welding machine sticks the two 
 parts together solidly enough so that the tube can be removed 
 to the mandrel of a rolling machine, exactly as is done when 
 welding by the oil-furnace method, and the weld is then com- 
 pleted in a few seconds by rolling down the joint. 
 
 Since it is always necessary to scarf the ends of a tube 
 and new safe-end before welding by the oil-furnace 
 method, the first question that the practical boiler-shop man 
 
 324 
 
WELDING BOILER TUBES 
 
 325 
 
 will ask is, How much preparation is needed for electric resist- 
 ance welding? The first step in any method is to clear the 
 tube from heavy scale, if in use under bad water conditions, 
 by rolling in a large tumbling barrel. After this, the tubes 
 are cut to the desired length to remove the old end that is 
 to be replaced by the new section. 
 
 In some shops it is the practice to never allow more than 
 one or two welds in a tube, which means that after removing 
 the second time, the tube must be used in a shorter boiler than 
 before. This procedure is carried out until the tube can only 
 
 FlG. 272. Machine for Cutting Off Flues. 
 
 be used for small switching locomotives if it lasts that long 
 after which it is scrapped. By this method, only one length 
 of tube is bought new, which is that required for the longest 
 boilers. 
 
 In other shops the writer found tubes with many welds, 
 showing that the safe-ending was continued in order to main- 
 tain the same length each time until the tube was worn out, 
 when it was replaced by a new one of the required length. 
 This latter method necessitates buying several lengths new 
 but in localities where the water is not very hard on tubes, 
 it prevents a tube from going to the scrap pile as long as there 
 
326 
 
 ELECTRIC WELDING 
 
 is any good in it. After cutting off the old tubes, as shown 
 in Fig. 272, which represents a common type of machine for 
 this purpose, the tubes are next scarfed, or cut off square, 
 according to which method of welding is to be employed. 
 If a scarf weld is to be used, the old tube is generally 
 
 ////7////////////////y/w///^ 
 
 
 ^Y////////7///////////////. 
 
 Old Tube 
 
 
 
 Hew End ' 
 
 7/////////////////////////S 
 
 Y////////////////////////// 
 
 FIG. 273. Ends Prepared for Scarf- Weld. 
 
 Fie. 274. Bolt Threading Machine Made Into a Scarfing Machine. 
 
 beveled on the outside at an angle of from 45 to 60 deg., 
 according to the length of scarf desired, about as shown in 
 Fig. 273. The bevel is wholly a matter of personal opinion 
 for just as good welds can be made with a 30-deg. scarf as 
 when one of 60 deg. is used. 
 
WELDING BOILER TUBES 
 
 327 
 
 One type of machine used for scarfing is shown in Fig. 274. 
 This has been rigged up from an old bolt-threading machine. 
 The jaws shown at the left are for gripping the old tube which 
 is then fed into a revolving chuck by means of the handwheel. 
 This chuck contains the necessary cutters for forming the 
 desired bevel on the outside of the tube end. The jaws on 
 the right-hand side of the same machine grip the new short 
 ends as they are fed onto a revolving tapered reamer, which 
 cuts a scarf from the inside. In some shops, the scarfing is 
 done on an old lathe with special fixtures, but the remodeled 
 bolt-threading machine seems to offer the most efficient proposi- 
 tion for, with this type of machine, it is possible for one man 
 to scarf over 60 tubes and ends per hour. 
 
 Old Tube 
 
 End 
 
 
 FIG. 275. Ends Prepared for a Straight Butt-Weld. 
 
 If a straight butt-weld is to be made instead of scarfing 
 the ends to be joined, they are cut off squarely, as shown 
 in Fig. 275. This is done in an old pipe-threading machine, 
 or a lathe, so that when placed in the welding machine, the 
 abutting ends will be in contact practically all the way around 
 their circumference. Although this last method of preparing 
 work may sound shorter than scarfing, nevertheless, from actual 
 observation of both methods in different shops, the former is 
 faster by nearly two to one. 
 
 After preparing the ends for welding, if the tubes have 
 not already been tumbled to remove all scale, which usually 
 leaves the outside surface quite bright and clean, it is necessary 
 to grind the surface of both old tube and new ends back to 
 a distance of about 8 in. in order to secure a good electrical 
 
328 ELECTRIC WELDING 
 
 contact between the tube metal and the copper jaws of the 
 welding machine. 
 
 There are three distinct methods of welding boiler tubes, 
 which are called butt-, scarf- and flash-welding, the latter 
 producing the same effect as a scarfed joint when completed. 
 In the straight butt-weld, the ends to be joined are first brought 
 firmly together by means of the pressure device on the welding 
 machine, and the current is then turned on. There is always 
 some point around the circumference of the tube which starts 
 to heat first, due to the impossibility of making the two ends 
 to abut with the same pressure at all points of their contacting 
 surfaces. However, the heat will gradually become uniform 
 all around the circumference before the welding temperature 
 is reached. The current is maintained through the tubes until 
 the joint reaches a good running heat, as evidenced by a 
 " greasy" appearance of the surface, when the pressure is 
 applied sufficiently to push up the hot metal about -J in. which 
 partly completes the weld. The jaws are then released and 
 the tube is immediately thrust onto the mandrel of the rolling 
 apparatus, which is described further on, and the bulge at 
 the joint, caused by the pushing up of the hot metal, is rolled 
 down until the joint is of the same diameter as the original 
 tube. 
 
 This rolling-down operation, in addition to reducing this 
 bulge of the tube, also forces a complete union of the plastic 
 metal of the two pieces, thereby completing the weld. From 
 this it may be seen that in welding boiler tubes, the welding 
 machine is only used for a heating device to supplant the oil 
 furnace, requiring only sufficient pressure to stick the ends 
 together to hold it while removing work to the rolling machine 
 where the welding is finished. 
 
 In the scarf weld, the beveled end of the old tube is pushed 
 into the chamfered end of the new piece and the current then 
 turned on the same as in making the butt-weld just described. 
 Due to the "feather" edge of the short new piece, it is often 
 necessary to apply the current intermittently until the joint 
 is well heated all around the circumference; otherwise points 
 of the sharp edge, which come in contact first with the opposite 
 member, will be burned off before the heat is evenly distributed 
 around the tube. Owing to the expanding effect of the scarfed 
 
WELDING BOILER TUBES 
 
 329 
 
 ends, it is not necessary to apply so much pressure as with 
 the butt-weld when the metal is plastic in order to stick the 
 pieces together before rolling down. 
 
 With either of the above welds, it is necessary to give the 
 old tube more projection beyond the copper clamping jaws 
 than is given the new short piece. This is because the wall 
 thickness of the old tube has been slightly reduced by wearing 
 away in service and if the two parts were given the same 
 projection, the end of old tube would heat much more rapidly 
 than that of the new piece since its resistance to the electric 
 current would be greater, owing to the reduced sectional area. 
 It is always necessary for the heat to form uniformly in each 
 
 Old Tube 
 
 New End 
 
 FIG. 276. Ends Prepared for a Flash- Weld. 
 
 of the abutting ends or one will burn away before the other 
 reaches the plastic stage. 
 
 In making a flash-weld, not so much preparation is required 
 as for the two other methods just described; hence it is a 
 much cheaper job and yet, from all tests made so far, it is 
 the only type of joint which is always 100 per cent perfect 
 when considering the number of defective welds in any lot 
 of tubes. The old tube is cut off the right length in a machine, 
 which has a cutting wheel so beveled as to give an angle of 
 30 deg. from the vertical on the end of the tube, as shown in 
 Fig. 276. The new ends are bought direct from the tube 
 manufacturers with both ends cut square and the surface 
 cleaned well so that there is no preparation needed on the 
 new pieces. After cutting off the. old tube it is only necessary 
 to grind it on the outside about 8 in. back from the end to 
 insure good electrical contact. The old tube is placed in the 
 
330 ELECTRIC WELDING 
 
 clamps with about 4 in. of projection and the new end with 
 about 3 in. The current is turned on first and the pressure 
 is then applied very slowly and steadily to bring the abutting 
 ends into contact. As soon as they meet, a small arc or ' * flash ' ' 
 is formed which commences to burn away the points of metal 
 coming into contact first. This flashing is continued until the 
 abutting ends are arcing all the way around the circumference 
 and by this time the sharp edge of the old tube, although 
 somewhat burned away itself, has burned its way into the 
 square-cut end of the new piece. A sudden application of more 
 pressure stops the flashing and the joint then quickly attains 
 the running or welding heat as in the butt- or scarf-welding 
 method. The ends are now shoved together and as the current 
 is turned off, the end of the old tube will have forced itself 
 into the end of the new piece sufficiently to form a scarf-weld 
 when rolled down in the rolling machine. 
 
 Using a Flux. From statements made by every operator 
 interviewed, the use of flux does not help the welding in any 
 way; yet it is used in each shop because it clears up the 
 surface of the metal when the plastic stage is reached and 
 enables the operator to judge the appearance of the heat more 
 easily. The writer is confident that if a new operator were 
 to be broken in on a welding machine, he would soon be able 
 to correctly judge the right welding heat of the metal by its 
 appearance without any flux, as there are many pipe shops 
 using electric-welding machines for making joints in long coils, 
 where flux was never heard of. Each railroad shop uses a 
 slightly different kind of flux, but generally this material is 
 nothing more than a common yellow clay, streaked with quartz 
 formation, which has been pulverized and thoroughly dried 
 out before using. 
 
 There are several methods and machines employed in the 
 various shops for rolling down and completing the weld after 
 heating the joint properly. One of the simplest machines in 
 use is shown in Fig. 277. It consists of a power-driven mandrel 
 slightly smaller than the internal tube diameter, above which 
 is a power-driven roller. This roller is held a short distance 
 above the mandrel by a spring. When the hot tube is thrust 
 onto the mandrel, the upper roller is brought firmly down onto 
 the outside surface of the joint by pressure on a foot treadle 
 
WELDING BOILER TUBES 
 
 331 
 
 located under the table on which the device is mounted. The 
 pressure is maintained until the joint has been rolled down 
 to outer tube size. The main disadvantage of this style of 
 apparatus is that the speeds of the roller and the mandrel must 
 be in the correct ratio so as to not allow any slip on either 
 inner or outer surface of the tube, otherwise the tube will roll 
 unevenly and when finished will have a thicker wall on one 
 side than on the other. However, this is the earliest form of 
 rolling machine used with the electric-welding method and 
 
 FIG. 277. Simplest Form of Boiling Machine. 
 
 is still giving fairly satisfactory service in two well-known 
 shops today. 
 
 Another type, which is more elaborate but more positive, 
 is a three-roller machine, shown in Fig. 278. The mandrel 
 here is stationary and the three idling rollers, being mounted 
 on a power-driven head, continually revolve around it. After 
 inserting the tube, which is also held stationary, pressure is 
 applied by means of a hand lever which closes the three rollers 
 in toward the center of the mandrel and the joint is rolled 
 down by the surface pressure of the three rollers revolving 
 around it. In order to still further insure uniform rolling, 
 the tube is turned slightly on the mandrel three or four times 
 
332 
 
 ELECTRIC WELDING 
 
 during the rolling operation since the mandrel is slightly 
 smaller than the tube and if the latter were to be held in only 
 one position, a difference in wall thickness on one side might 
 result. 
 
 Rolling machines of the types just described are sometimes 
 located in direct alignment with the jaws of the welding 
 machine, so that after obtaining the proper heat, it is only 
 necessary to release the jaws and shove the hot tube directly 
 
 FIG. 278. The Three-Boiler, or Hartz Type, Machine). 
 
 onto the mandrel. If the three-roller type is being used, the 
 tube is held stationary by locking one jaw of the welding 
 machine. When a new position on the mandrel is desired the 
 jaws are released and the tube allowed to turn slightly with 
 the friction of the revolving rollers. 
 
 Another method is to have the rolling machine in back of 
 the welding machine so that when the correct heat is obtained, 
 the tube is lifted out of the jaws by the operator's assistant 
 
WELDING BOILER TUBES 333 
 
 who shoves it onto the rolling mandrel, leaving the operator 
 free to get the next tube lined up in the machine for heating. 
 In this last method, the assistant must act quickly so as not 
 to allow the joint to cool down before the rolling, as he cannot 
 transfer the tube from the welding to the rolling machine as 
 quickly as the operator could shove it forward onto the mandrel 
 as first mentioned. 
 
 As to speed in welding, the writer observed that the same 
 production could be obtained in different shops by either 
 method of locating the rolling machine ; hence it is purely a 
 matter of space available around the welding machine, and 
 local opinion. 
 
 A third way of handling the rolling down is to have the 
 rolling machine built onto the welding machine, as shown in 
 Fig. 279. In this particular apparatus, the mandrel is made 
 long enough to permit welding in to a distance of 10 ft. from 
 the joint, so as to reclaim old short tubes by making a new 
 long one with a joint in the middle. This reclaiming of tubes 
 has proved to be perfectly practical, having been forced in 
 one locomotive shop during the war due to the inability to 
 obtain new tube stock. The mandrel is power driven as well 
 as the upper roller, while the two lower rollers are idlers. 
 After obtaining the welding heat, it is only necessary to move 
 the tube about one foot to bring the joint onto the rollers. 
 A clutch at the rear end is then thrown in to revolve the 
 mandrel and upper roller, and pressure is applied through the 
 latter by means of an air cylinder mounted above it. While 
 being rolled the tube is allowed to revolve freely in the open 
 jaws of the welding machine. The rear end of the tube is 
 supported on idling rollers. 
 
 After the rolling-down process, which is the same as has 
 always been used with the oil-furnace method of welding, the 
 tubes are subjected to the annealing and end-swaging processes. 
 They are then usually tested hydrostatically for possible leaks 
 and stacked away ready for assembling in the boiler. The 
 percentage of leaks is less than 5 per cent in any shop, and 
 in one shop they are so sure of their welding that the tubes 
 are not tested until completely assembled in the boiler when 
 the latter is subjected to a hydrostatic test as a complete unit. 
 This particular shop uses the flash-weld method and has never 
 
334 
 
 ELECTRIC WELDING 
 
 I 
 
 I 
 be 
 
WELDING BOILER TUBES 335 
 
 had a defective joint since the welding machine was installed 
 over four years ago. 
 
 Merits of Electric and Oil Heating. When asked to com- 
 pare the electric welding with the oil-furnace method on boiler 
 tubes of any size, one of the oldest users of the former replied 
 that there was "no comparison." Using oil it was never 
 possible to average over 30 or 40 welds per hour on tubes 
 up to 3 in. with one furnace and one gang. This meant that 
 the tube shop was always behind the rest of the repair depart- 
 ments and working overtime a great deal in order to catch up. 
 Fuel oil will vary greatly in different lots as well as under 
 different atmospheric conditions, so the oil furnace itself is 
 a constant source of aggravation and calls for continual adjust- 
 ing, which means an interruption in production while the fire 
 is regulated. 
 
 As to production with an electric-welding machine, the 
 average output on tubes up to 3 in. in diameter, taken from 
 all shops using this process, will run 60 completed welds per 
 hour, requiring one operator and a helper at the machine and 
 a third man to prepare the work for welding. In the days 
 of piecework, in some of the shops, records show that the 
 maximum number of small tubes turned out in any shop, 
 with the same number of men, was 125 per hour or a little 
 better than one tube every 30 sec. and this could be kept up 
 for two hours at a time without greatly tiring the men. This 
 speed was obtained by three different shops, each using a 
 different style and arrangement of rolling-down apparatus, 
 which shows that all of the methods outlined previously in this 
 article are equally fast. 
 
 On welding superheater tubes at the reduced section, where 
 the diameter at the point of weld is about 4f in., the production 
 will run about 10 to 20 welds per hour, although better time 
 has been made on piecework. By comparing these figures with 
 the oil-furnace welding production, even under the best of 
 working conditions, nothing further need be said as to the 
 speed of the electric process. 
 
 As to cost, there are no figures available later than 1916, 
 which of course would be much lower than at the present day, 
 but by comparing costs of both methods at that time, taking 
 into consideration upkeep, labor, cost of heat either way and 
 
336 ELECTRIC WELDING 
 
 cost of time lost by making adjustments or repairs to either 
 apparatus, the electric costs per 1,000 tubes welded, is about 
 one-third that of the oil-furnace method. 
 
 The only wear on the welding machine is the surface of 
 the copper dies or jaws which grip the pieces and this is so 
 slight as to only require smoothing off a few times a week. 
 The machine docs not cost anything for heating energy except 
 when the weld is being made and it is always ready for action 
 as soon as the operator has placed the work in the jaws. Hence 
 there is no delay in starting up the fire in the morning or 
 after lunch hour nor from the fire balking at any time during 
 the welding. The replacements on welding machines in all 
 the shops visited by the writer could be easily covered by $100 
 during the last six years. 
 
 In recapitulating the three methods of electric welding flues, 
 it is safe to say that the flash-weld, which produces a scarfed 
 joint when finished, takes the lead for simplicity of preparation, 
 speed of actual welding and reliability as to percentage of 
 failures in any lot of tubes. 
 
 Next to this comes the straight scarf-weld, which requires 
 machining of the ends before welding but insures a good joint 
 after welding although occasionally a small leak will show 
 up on the first hydrostatic test. As stated before, the per- 
 centage of leaks is very low with this type of weld and 
 practically negligible with the flash-weld. 
 
 The butt-weld, which was originally employed in all the 
 shops, is now only used in one shop in the whole country, prob- 
 ably due to the difficulty in making a perfect weld each time 
 as compared to the ease of making a scarf weld. However, 
 this one shop claims very high efficiency with a butt-weld, 
 both as to tensile strength, which will average over 85 per 
 cent of original tube section, and as to tightness of the joint 
 under pressure. 
 
 The principal objection offered by most shops against butt- 
 welding is that should the weld prove tight under pressure, 
 but still be a weak joint mechanically, it might break apart 
 in service. This has happened in a few cases, allowing the 
 tube to drop down in the boiler and subjecting the engine 
 crew to the danger of scalding. With a scarf-weld, which 
 generally shows a tensile strength equal to that of the original 
 
WELDING BOILER TUBES 
 
 337 
 
 tube, due to the area of the weld, should the tube not be 
 welded strongly as just cited and a break should occur inside 
 the boiler, the scarf would prevent the tube from pulling away 
 from its end and only a slow leak could result. This some- 
 times actually happens with oil-furnace welded tubes. 
 
 The Kind of Machine to Use. As there are different styles 
 and sizes of welding machines being used at the present time 
 on flue-welding, the writer will endeavor to specify special 
 characteristics that should be sought when selecting a machine 
 for this class of work, which is different from any other pipe- 
 welding job. The machine should be constructed to be as 
 efficient electrically as possible ; that is, the clamping jaw should 
 be as close to the transformer as is practical in order not to 
 
 Copper Jaws 
 
 Recess*, 
 -"s. 
 
 / \ 
 Join 
 
 fl 
 
 Recess, 1 
 
 _., JrLJ 
 
 
 
 A 
 
 1 
 
 
 
 
 i 
 
 Contact 
 
 A 
 
 i 
 
 A 
 i 
 
 ^Contact 
 
 OldTube' Wew Tube 
 End View Top View 
 
 FIG. 280. Eecessed Copper Clamping Jaws. 
 
 have large inductive losses caused by the large gap due to 
 the long secondary leads widely spaced. The fewer the joints 
 between the secondary loop of the transformer and the copper 
 jaws which grip the tube, the less chance will there be for 
 resistance losses that cut down the heating effect gradually as 
 oxides form in the joints or by dirt collecting from allowing 
 them to become loose. Although the jaws should be long to 
 permit thorough water cooling, it is only necessary to grip 
 the pipe over a length of about 2 in. This length is bored 
 out to exactly fit around the tube as shown in Fig. 280. 
 
 The pressure device does not need to be as heavy as would 
 be used on the same welding machine for joining ordinary pipe 
 or solid stock, since the squeezing together of the plastic metal 
 
338 ELECTRIC WELDING 
 
 is really done in the rolling machine. For fastest operation the 
 clamping jaws should be operated by air cylinders so that only 
 a slight movement of two valves is necessary to lock or unlock 
 the tube in the jaws. 
 
 For welding up to 3-in. size tubes, a machine of 30-kw. 
 rating ought to be large enough to stand constant use. Any 
 form of toggle lever or screw-wheel pressure device, which 
 permits the operator to stand close to the work will be suitable, 
 as not over 1,000 Ib. effective pressure is required on this size 
 of work to stick the ends together sufficiently hard for placing 
 in the rolling machine. 
 
 To handle up to 5f-in. superheater tubes, a machine of 
 about 75-kw. rating should be employed. For its pressure 
 device, an air cylinder or hydraulic apparatus may be used 
 to best advantage so as to secure up to three or four tons' 
 maximum effective pressure. 
 
 For ordinary butt- or scarf-welding, a hand-operated oil 
 jack may be used, although trouble has been experienced in 
 the past with this type of pressure device due to sticking of 
 the valves at critical times, often spoiling a weld. 
 
 Flash- Welding. For flash-welding, a toggle lever or hand- 
 screw wheel on small machines and an air cylinder or hydraulic 
 pressure device on large machines must be used, to effect a 
 slow steady forward movement of the movable jaw in order 
 to maintain the arc of the flashing, yet to have available a 
 quick reverse to break the parts away should they stick too 
 soon from too rapid movement of the pressure device. In small 
 shops, it is advisable to install a 75-kw. machine to handle 
 all sizes of tubes up to the largest superheater. If the shop 
 is large enough to keep a small machine busy all the time on 
 tubes up to 3 in., it will no doubt pay to install in addition, 
 a large machine just to handle the superheater tubes as well 
 as any overflow lot of small tubes. While the large machine 
 will handle any size, it is not so rapid in operation on small 
 tubes as the smaller one, and the bulk of flue-welding is on 
 small tubes, less than 10 per cent of the total being represented 
 by the larger sizes for superheaters. 
 
WELDING BOILER TUBES 
 
 339 
 
 WELDING IN THE TOPEKA SHOPS OF THE SANTA FE RAILROAD 
 
 Supplementing the foregoing, we give the following extract 
 from an article published in the American Machinist, June 
 8, 1916: 
 
 In order to give the gripping jaws of the welder good, 
 clean contact the ends of the pieces are ground on the outside 
 for about 6 or 7 in. back from the ends, the operator simply 
 
 FIG. 281. Close-Up Showing Inside Mandrel. 
 
 revolving the tube end against the grinding wheel. The ground 
 pieces are sorted out into suitable lengths to form full-length 
 flues when two pieces are butted together, keeping in mind 
 that only two welds are allowed to a flue. 
 
 The butt-welding machine itself is practically as received, 
 but the inside mandrel and outside rolls, together with the 
 driving mechanism, were added in the shop after considerable 
 experimenting. Without these the method would be a failure. 
 
 A close-up view of the machine, from the back, is given 
 in Fig. 281. This shows the mandrel A that works inside the 
 
340 
 
 ELECTRIC WELDING 
 
 FIG. 282. Flue Parts Beady for Welding. 
 
 FiG. 283. Flue Eiids Just Beginning to Heat. 
 
WELDING BOILER TUBES 
 
 341 
 
 FIG. 284. Almost Hot Enough for Welding. 
 
 FIG. 285. Rolling Out the Upset Metal. 
 
342 ELECTRIC WELDING 
 
 flue as the outside is rolled between the three rolls after the 
 parts have been heated and butted together. The action of 
 the mandrel and rolls is to take out the upset and give a weld 
 that is smooth on the outside and with very little extra metal 
 inside. The gripping jaws are water-cooled, and the operating 
 air cylinders are plainly shown. 
 
 Fig. 282 shows two parts of a flue in place in the jaws 
 and illustrates how it is slipped over the mandrel. It will 
 be observed that the mandrel does not extend far enough 
 beyond the rolls to interfere with the welding or become heated 
 from the current passing between the jaws. As it is impossible 
 always to have the two parts to be welded of the same thick- 
 ness, the setting of the pieces in the jaws must be done with 
 judgment. If one piece is thinner than the other and they 
 were both set in the jaws the same distance out, the thin one 
 would burn before the thick one was hot enough to weld 
 properly. To avoid this, a thick and a thin piece are placed 
 about as shown at A and B. In this case the thick one is at 
 A and the thin one at B. As the thick one is in closer to the 
 jaw, it will heat faster. The thin one, being set out farther, 
 gives practically the same amount of metal for the current to 
 heat. The result is an even heating and a perfect weld. 
 
 Fig. 283 shows two pieces the reverse of the ones just shown. 
 As the work gradually heats, it looks as in Fig. 284. At the 
 proper heat, the operator butts the work together to form the 
 weld, which leaves a considerable amount of upset. He then 
 shoves the tube along over the mandrel until the weld is be- 
 tween the rolls, when he throws in the clutch and brings down 
 the upper roll. The work spins between the rolls, as shown 
 in Fig. 285 and the result looks almost like a new tube. 
 
CHAPTER XV 
 
 ELECTRIC WELDING OF HIGH-SPEED STEEL AND 
 STELLITE IN TOOL MANUFACTURE 
 
 The cost of solid high-speed cutting tools is high. At the 
 same time their remarkable cutting qualities make them a 
 necessity in up-to-date shop practice. The electric process of 
 butt-welding has made it possible to obtain all the advantages 
 of a solid high-speed cutting tool and yet at a cost that is 
 not a great deal higher than the ordinary tool-steel product. 
 Stellite, -which has recently become more widely known, has 
 been rather limited in its use owing to the fact that it cannot 
 be machined, and it has been thought .by many that it could 
 not be successfully joined to any other metal for holding it. 
 This has limited its use to special forms of toolholders, which 
 are often very clumsy in getting into difficult corners on 
 special shapes. The electric process of butt-welding has made 
 it possible to join Stellite bits of any common size and shape 
 to a shank of ordinary steel, giving all the advantages of a 
 solid cutting tool and yet employing only a small amount of 
 the Stellite metal just where it is needed for cutting. 
 
 The Thomson welding process consists of passing a large 
 volume of electric current at a low pressure through the joint 
 made by butting two pieces of metal together. The electrical 
 resistance of the metals at the contacting surface is so great 
 that they soon become heated to a welding temperature. Pres- 
 sure is then applied mechanically and -the current turned off, 
 thereby producing a weld. The metal is in full view of the 
 operator at all times instead of being hidden by the coal of 
 a forge or by flame in an oil furnace. No smoked glasses or 
 goggles are required any more than would be if welding by 
 the forge method. Due to the way the metal is forced together 
 there is no oxidation such as there would be in an open fire 
 and therefore no welding compound is ordinarily required. 
 
 343 
 
344 ELECTRIC WELDING 
 
 It is this feature alone which makes it possible to weld high- 
 speed steel and Stellite, the former being very difficult to weld 
 by the forge method and the latter practically impossible. 
 "With this process of electric welding the heat is first developed 
 in the interior of the metal. Consequently, it is welded there 
 as perfectly as at the surface. When welding with other 
 methods, however, the outer surface is heated first and very 
 often the interior part does not reach welding heat, the result 
 being an imperfect weld. There is no blistering or burning 
 of the stock when welding electrically, whereas it certainly 
 requires a very expert welder indeed to secure the proper heat 
 on high-speed steel in a forge fire without burning at some 
 point. The process is the most economical known, due to the 
 fact that no energy in the form of heat is being wasted in 
 heating more of the material than is required to make a weld 
 and as soon as it has been completed the current is turned 
 off so that the machine then is not using up any energy what- 
 ever. The operator has complete control of the current at all 
 times so that he can obtain any color desired on the metals, 
 where are always visible, and waste by accidental burning of 
 metal is reduced to a minimum. 
 
 The only preparation of stock necessary for welding by this 
 process is that when very rusty or greasy it should be thor- 
 oughly cleaned, as the presence of either rust or heavy grease 
 affords poor contact with the copper clamping jaws, retarding 
 the flow of electricity and seriously reducing the heating effect. 
 
 It is often asked if the electric current has any effect on 
 the welded metal. This question arises from the fear that there 
 may be some mysterious condition connected with electricity 
 that will change the characteristics of the metal, particularly 
 of high-speed steel or Stellite. The answer is, of course, in 
 the negative, as the only effect of the electric current is to 
 heat the metals being welded. 
 
 The rapidity of work will depend largely on the operator, 
 the size and shape of the pieces to be welded and the size of 
 machine being used, as there is a wide range in welding time 
 between heavy pieces requiring careful alignment in the clamp- 
 ing jaws and light pieces which can be rapidly and easily 
 handled. 
 
 Welding High-Speed to Low-Carbon Steel. In tool welding 
 
ELECTRIC WELDING OF HIGH-SPEED STEEL 
 
 345 
 
 there are various kinds of welds to be made, which require 
 different designs of holding jaws and often two distinct types 
 of welding machine. 
 
 Three butt-welding machines shown in Figs. 286, 287, and 
 288 are especially suitable for welding drills, reamers or other 
 
 FIG. 286. Thomson 10-A6 Butt -Welding Machine. 
 
 tools that can be made up of a combination of high-speed and 
 low-carbon steel. The machine shown in Fig. 286, known as 
 the 10-A6 machine, will weld iron or steel rods from J to J in. 
 in diameter, or an equivalent cross-section in squares, rectangles 
 or flats. An operator can make from 50 to 200 welds per hour, 
 "'.cording to the size and nature of the work being handled. 
 
346 ELECTRIC WELDING 
 
 The clamps are of the horizontal operating type, adjustable 
 for different sizes of stock as well as for horizontal alignment 
 of the work. A close-up view of the left-hand clamping 
 mechanism is shown in Fig. 287. The jaw blocks are water 
 cooled and have a maximum movement of 1J in. by means 
 of the hand-operated clamping levers. There is also a possible 
 f-in. adjustment of both front and rear jaw blocks. Stops 
 are provided for backing up the work. There are four copper 
 jaws to a set, two being used on each clamp. These jaws are 
 
 FIG. 287. Closeup View of Left-Hand Clamp. 
 
 2y z in. square by 1 7 / 1C in. thick. The pressure device for 
 forcing the heated ends of the work together is a hand-lever- 
 operated toggle movement, which enables the operator to "feel" 
 his work. This toggle device gives a movement of 1 in. to 
 the right-hand jaw. The maximum space possible between 
 the jaws is 3J in. There is an automatic current cutoff mounted 
 on the machine. The standard windings are for 220, 440 and 
 550 volt, 60-cycle alternating current. The current variation 
 for different sized stock is effected through a five-point switch 
 
ELECTRIC WELDING OF HIGH-SPEED STEEL 
 
 347 
 
 mounted on the machine. Standard ratings are 15 kw., or 
 25. k.v.a., with 60 per cent, power factor. This size of machine 
 covers a floor space 43X57 in., is 65 in. high and weighs about 
 1100 pounds. 
 
 The machine shown in Fig. 288, or the No. 6 machine, is 
 for heavier work, its capacity being from to 1 in. in diameter 
 on iron or steel rods, or the equivalent in other shapes. Its 
 production is from 50 to 125 welds per hour. The maximum 
 jaw opening is 3 in. ; the four jaws are of hard-drawn copper, 
 2JX2f in. and 1 in. thick; toggle-lever movement 1^ in.; 
 
 FIG. 288. No. 6 Butt-Welding Machine. 
 
 maximum space between jaws, 4 in.; current standards are 
 the same as for the previous machine. There are 10 points of 
 current variation for different sized stock, effected through 
 double-control switches mounted on the machine. Standard 
 ratings are 30 kw. or 45 kva., with 60 per cent, power factor. 
 The jaws are air cooled, but the copper slides to which the 
 jaws are bolted, as well as the secondary copper casting of 
 the transformer, are water cooled. It occupies a floor space 
 22X44 in. and the height to center line of the jaws is 37^ in. 
 The weight is 3100 Ib. Its operation is practically the same 
 as the first machine described. 
 
 Another machine of very similar characteristics is shown 
 
348 
 
 ELECTRIC WELDING 
 
 in Fig. 289. This is known as the Special 5-D machine and 
 is intended for the use of makers of small taps and twist drills 
 up to f in. in diameter. It has very accurate adjustments on 
 
 FIG. 289. Special 5-D Machine. 
 
 the clamps and special jaws with steel inserts to prevent wear. 
 To use these, however, requires that the pieces to be welded 
 must be finished to uniform size so as to accurately fit the jaws 
 in order to conduct the current properly. 
 
 FIG. 290. Stellite-Tipped Roughing Drills. 
 
 The machines shown in Figs. 286 and 288 are not only 
 good for welding the steels mentioned, but also for Stellite 
 work, samples of which are shown in Fig.- 290, since the com- 
 
ELECTRIC WELDING OF HIGH-SPEED STEEL 
 
 349 
 
 monly used bits of this metal are within their range. The 
 hand-lever toggle action is quicker and is better suited to this 
 work than the hydraulic-pressure device used on some of the 
 larger machines. 
 
 In welding twist drill or reamer blanks, such as shown in 
 Fig. 291, not over } in. in diameter, it has been found practical 
 
 FIG. 291. Twist-Drill Blanks Just Welded. 
 
 to use a pair of jaws on each side that will handle all work 
 from the smallest up to the J-in. size. These jaws are made 
 as shown in Fig. 292. The two rear, or movable, jaws on each 
 side of the machine are flat faced, while the front, or stationary, 
 jaws, have a V-groove cut in them just deep enough to give 
 clearance for the smallest size of stock to be handled in contact 
 
 Round Stock 
 being welded 
 
 MOVABLE: 
 DIE 
 
 STATIOtMRY 
 DIE 
 
 Section Through Dies and Work 
 
 FIG. 292. Copper Jaws for Various Sizes. 
 
 with the face of the opposite jaw. The work is held in the 
 jaws with a three-point contact, which has been found to be 
 sufficient for stock of this size, although it is not to be recom- 
 mended for larger work, since not enough current could be 
 carried into the pieces without applying pressure sufficient to 
 squeeze the work into the surface of the copper jaws. This 
 would soon spoil all accuracy of alignment of the V-grooves. 
 
350 
 
 ELECTRIC WELDING 
 
 In this connection it may be well to mention that a welding 
 machine is not a micrometer and the welding of finished pieces 
 is not recommended in commercial production, although such 
 welding is done right along for special jobs. By "special 
 jobs" is meant the putting on of an extension to a drill, tap 
 or small reamer and the like. 
 
 In welding high-speed to low-carbon steel the low-carbon 
 steel sliould project approximately twice as far out from the 
 jaws as the high-speed steel does in order to equalize as much 
 as possible the heating of the two pieces. 
 
 Where a tool is to be made with a head larger than the 
 shank, as shown at A, Fig. 293, holding copper jaws should 
 
 HIGH- 
 SPEED 
 
 STEEL 
 
 I WELD 
 
 J 
 
 LOW-CARBON STEEL 
 
 (A) 
 
 LOW CARBON 
 STEEL 
 
 (a) JAWS OFWELDER,GROOVED /^, 
 FOR ROUND STOCK ( D j 
 
 End View 
 FIG. 293. Copper Jaws for Holding Large Heads and Small Shanks. 
 
 be made as shown at D. In work of this kind the dimension 
 B should always be about one-half of the diameter of C. The 
 same rule holds good with this type of tool blank when placing 
 it in the jaws as with steel of the same relative size ; that is, 
 the low-carbon steel should project about twice as far from 
 the jaws as the high-speed steel since the high-speed steel has 
 the higher resistance and lias a tendency to become plastic 
 sooner. To still further reduce its tendency to heat up quickly, 
 the resistance should be reduced as much as possible by having 
 the jaws as good a fit for the high-speed piece as it is possible 
 to make them. Where different sizes are to be welded it is 
 advisable to have special holding jaws for each separate size 
 of high-speed steel head, although the low-carbon steel pieces 
 may be held in V-grooved jaws made up to hold several sizes. 
 
ELECTRIC WELDING OF HIGH-SPEED STEEL 351 
 
352 
 
 ELECTRIC WELDING 
 
 This is the practice of some of the largest makers of reamers 
 and large drills. 
 
 The actual use of the machines shown for the work outlined 
 is simplicity itself. The work is placed in the respective jaws 
 and securely locked in place by pulling forward the two levers 
 shown projecting upward on each machine. In addition to 
 the grip of the jaws the work is kept from any possible slip 
 by means of stops against which the outer ends of the work 
 are butted. With the work solidly in place the operator pulls 
 
 FIG. 295. Close-up of Machine with Work iu Jaws. 
 
 on the pressure lever at the right of the machine until the 
 ends of the work are in firm contact. He then turns on the 
 current by means of a push button conveniently located in the 
 pressure lever, and when the proper heat is reached, which 
 is judged by the color, the push button is released. This shuts 
 off the current and the operator then applies full pressure and 
 the weld is made. 
 
 The maximum capacity of the largest of the three machines 
 described is 1 in. round or its equivalent in other shapes. For 
 larger work a machine similar to the one shown in Fig. 294 
 
ELECTRIC WELDING OF HIGH-SPEED STEEL 353 
 
 is used. This is known as a No. 9 butt-welding machine, and 
 its capacity is from to 1J in.; the output is from 50 to 100 
 welds per hour ; the maximum jaw opening is 1 J in. ; the four 
 hard-drawn copper jaws are 3 in. high, 3J in. wide and 1 in. 
 thick; the pressure device is a 5-ton hand-operated hydraulic 
 oil jack ; maximum movement with jack, 2 in. ; maximum move- 
 ment with one stroke of jack, ^ in. ; maximum opening between 
 jaws, 4 in. ; standard windings the same as for the previous 
 machines; standard ratings, 40 kw. or 55 kva., with 60 per 
 
 FIG. 296. Steps in the Making of a Large Reamer. 
 
 cent, power factor ; width of machine, 27 in. ; length, 60 in. ; 
 height, 46 in. ; weight, 3900 pounds. 
 
 A closeup of this machine, with a large reamer blank in 
 the jaws, is shown in Fig. 295, and progressive steps in the 
 making of the reamer are shown in Fig. 296. The high-speed 
 steel piece is 3 in. long by If in. diameter, and the machine- 
 steel piece is 6 in. long. 
 
 Two other machines (10-B and 40- A2 models) of this type 
 suitable for heavy tool welding may be mentioned. They are 
 made with a capacity of from to 1J and from 1 to 2 in. 
 
354 
 
 ELECTRIC WELDING 
 
 The first of these has a hand-operated pressure device capable 
 of exerting a pressure of 12 tons and it weighs 7800 Ib. The 
 second has a pressure device which receives its initial pressure 
 
 FIG. 297. A Welded and a Finished Lathe Tool. 
 
 from an external accumulator, which gives an effective pres- 
 sure of 23 tons; it weighs 8000 Ib. and is 64X105X48 in. high. 
 The Welding of Other Than Round Tools. The welding 
 
 .WELD 
 
 r- 
 
 \HIGH-SPEED 
 \ STEEL 
 
 LOW-CARBON STEEL 
 
 FlG. 298. How the Parts Are Arranged for Welding. 
 
 of tools similar to the ones shown in Fig. 297, intended for 
 lathe or planing-machine tools, may be done in any of the 
 foregoing machines. The cutting parts may be of either Stellite 
 
 End View (a)D/ BLOCKS or WELDER 
 
 FIG. 299. How the Parts Are Clamped in the Jaws. 
 
 or high-speed steel. This kind of welding is usually employed 
 by manufacturing concerns in their own toolrooms in order to 
 use up odd bits of high-priced steel or Stellite. The pieces arc 
 
ELECTRIC WELDING OF HIGH-SPEED STEEL 
 
 355 
 
 prepared about as shown in Fig. 298. Jaws for holding work 
 of this kind are outlined in Fig. 299. 
 
 Another way to make tools for lathe or planing-machine 
 work is outlined in Fig. 300. This method may often be 
 employed when the one just given could not. As can be seen, 
 
 HIGHSPEED 
 STEEL 
 
 WELD- 
 
 LOW CARBON STEEL 
 
 FIG. 300. Method of Preparing for an Insert Weld. 
 
 in order to properly support the high-speed steel piece, the 
 low-carbon steel shank is milled away to form a recess for 
 the reception of the high-speed steel bit. The welding can 
 be done on any of the machines shown provided the parts are 
 not of too great cross-section. The method of recessing the 
 copper clamping jaws is clearly shown in Fig. 301. 
 
 
 j 
 
 Co) 
 
 iws recessed 
 to hold pieces 
 
 
 a 
 
 
 a 
 
 a 
 
 1& 
 
 r 
 
 <-\ ,-> 
 
 Jtt-: ICAK 
 
 ?ED ' ST 
 
 T SH, 
 
 j 
 
 >BON- 
 r .EL 
 W/t 
 
 a 
 
 Top View of Work Meld Vertically 
 
 BIT 
 
 
 
 
 
 Ph 
 
 he 
 
 
 
 
 i 
 
 yon 
 sss 
 
 
 Pieces resting on 
 bottom of recess 
 
 Front View of Rear Jaws and Work 
 FIG. 301. Jaws Used for Holding Work in Insert Welding. 
 
 The perfect success of a welded high-speed tool depends 
 not only on the correct welding but also upon the correct 
 treatment after the welding itself has been accomplished. It 
 is easily seen that if a piece of high-speed steel is welded to 
 a piece of ordinary carbon steel and the joint allowed to cool 
 
356 
 
 ELECTRIC WELDING 
 
 fairly quickly in the air strains will be set up at the joint 
 for the reason that the high-speed steel in cooling so quickly, 
 both metals become hardened more or less but to a different 
 degree. Hence if the weld is subjected to any great strain 
 under these conditions it will break either at the joint or close 
 by , due to the strain. It is therefore very evident that 
 immediately after welding a piece of high-speed steel to carbon 
 steel the work should be immediately put into some sort of 
 furnace to be annealed. The amount of time that the tools 
 should be left in the furnace for thoroughly heating through 
 and the amount of time required to allow the pieces to cool 
 down to room temperature depend entirely upon the size and 
 
 Sfa tionaryja ws, only 
 
 
 recesseq 
 
 / 
 * "A 
 
 
 
 _______ _ _ 
 
 1 
 
 -i 
 
 1 
 
 HIGH- . 
 SPEED 
 BIT 
 
 CARBON f 
 STEEL "' 
 SHANK 
 
 
 
 Top View of WorK Held Horizontally 
 
 Piece resting on bottom ofrec&ss 
 
 
 V 
 
 T 
 
 
 End View of WorK 
 in Right-Hand Jaws 
 
 FIG. 302. Jaws Used for Stellite Butt Welding. 
 
 character of tool being made. However, the annealing of any 
 piece of any size requires that' the work be left in the furnace 
 heated to at least a dull cherry red for a few hours and allowed 
 to cool very slowly in the furnace. 
 
 If a welded tool is not properly annealed before machining 
 much difficulty is often experienced from hard spots being 
 encountered in the machining of the pieces, which of course 
 is more or less disastrous to the cutting edges of the tools being 
 used in the machining process. 
 
 The best method of hardening high-speed steel tools after 
 the welding and machining depends also greatly upon the shape 
 and size. 
 
 Welding Stellite, Although the welding of the various 
 
ELECTRIC WELDING OF HIGH-SPEED STEEL 
 
 357 
 
 grades of Stellite is not difficult there is a certain knack in the 
 welding and also in the clamping of the stock which must be 
 fully acquired to produce satisfactory results. 
 
 The welding should be done in a horizontal butt-welding 
 machine with a quick-acting hand-lever pressure device. In 
 butt-welding round drill stock or rectangular tool stock the 
 pieces should be held as shown in Fig. 302. It will be noticed 
 that the projection of the Stellite beyond the copper jaws 
 is very short indeed while the projection of the carbon-steel 
 
 J 
 
 aws re<. 
 hold pn 
 
 essec/ 
 >ces. 
 
 \ 
 
 to 
 
 
 
 j , 
 
 HIGH---' 
 SPEED 
 BIT 
 
 CARBON- 
 STEEL 
 SHANK 
 
 
 Top View of Work held Vertically 
 
 SHANK 
 
 ,,r 
 
 V- 
 
 
 r 
 
 Pieces resi 
 on bottot 
 recess 
 
 
 
 
 mg 
 n of 
 
 
 Front View of Rear Jaws and Work 
 FIG. 303. Jaws Used for Stellite Insert Welding. 
 
 piece is comparatively long. This is because Stellite has a 
 very high resistance compared with the carbon steel. Since 
 in this work the heating effect varies directly with the resist- 
 ance of two metals the heating in the Stellite should be retarded 
 as much as possible by surrounding it almost completely with 
 the copper jaws. The correct amount of projection of the 
 carbon steel will have to be determined by experiment in each 
 case after observing with each setting of two pieces which has 
 the tendency to heat the fastest. 
 
 In welding in cutting bits of Stellite by the insert-weld 
 method the pieces should be held as shown in Fig. 303. 
 
358 
 
 ELECTRIC WELDING 
 
 It will be seen from this cut that the copper jaws holding 
 the small bit nearly surround it and at the same time back 
 up the piece to take the pressure of the squeezing up of the 
 
 FIG. 304. Vertical Type of Welding Machine. 
 
 stock. The opposite jaws holding the carbon-steel shank do 
 not have to grip very much of the metal but they serve to 
 back it up to receive the force of the pressure. 
 
 In the welding itself the current is applied intermittently, 
 
ELECTRIC WELDING OF HIGH-SPEED STEEL 
 
 359 
 
 as the Stellite usually has a tendency to heat very rapidly, 
 until the carbon steel is fast approaching the plastic state. 
 The current is then held on steadily and the instant the Stellite 
 metal "runs," the pressure lever is given a quick jerk as thje 
 current is turned off. It will be found that with a good weld 
 there is scarcely any push up of the stock and very little of the 
 
 FIG. 305. Making a "Mash" Insert Weld in a 20-AV Machine. 
 
 metal flows out at the joint, requiring little grinding, if any, 
 to finish the tool. 
 
 Unlike high-speed steel Stellite requires no further heat 
 treatment or attention of any kind if it is welded correctly. 
 When it is taken out of the welding machine the tool is ready 
 for use at once after grinding off the resulting burr. 
 
360 
 
 ELECTRIC WELDING 
 
 Where large numbers of tools of the lathe and planing- 
 machine types are to be made, such as shown in Fig. 300, 
 the highest production can be obtained by using a Vertical 
 
 FIG. 306. Large 40-AV Vertical Machine. 
 
 type of welding machine built on the lines of the one shown 
 in Fig. 304. 
 
 This machine (10-AV model) has a capacity of two pieces 
 with contact areas between 0.40 and 0.30 sq. in. for pieces with 
 a total thickness of f to 1J in. The production is 35 to 85 
 tools per hour, depending on the size; the upper and lower 
 
ELECTRIC WELDING OF HIGH-SPEED STEEL 361 
 
 jaws are of hard-drawn copper 1|X2J in. and If in. thick; 
 the jaw blocks are water cooled; the machine has a current 
 variation through a five-point " switch for different sizes of 
 stock; standard windings are for alternating current 220 440 
 and 550 volt, 60 cycles; standard ratings, 15 kw. or 25 kva. 
 with power factor of 60 per cent. ; the pressure device is hand 
 operated, giving a movement of 2f in. ; maximum space between 
 jaws, 3| in.; floor space occupied, 21 X 53 in.; height, 75 in.: 
 weight, 1200 pounds. 
 
 A larger machine (20-AV model) of the same type in opera- 
 tion is shown in Fig. 305. This machine gives a maximum area 
 of contact ranging from 1| to 1 sq. in. on pieces with a total 
 thickness from 1 up to 2 in. ; production is from 50 to 75 welds 
 per hour ; there is a throat clearance of 10 in. ; the copper 
 jaws are 2X3 in. and 1| in. thick; pressure is by hand-toggle 
 
 FIG. 307. Jaws and Work Arranged for a "Mash" Weld. 
 
 lever and spring cushion; current control, as in the other 
 machines, is by push button in the lever operating through a 
 magnetic wall switch; the jaw blocks are water cooled; 
 standard ratings are 30 kw. or 50 kva'. with 60 per cent, power 
 factor; weight, 2200 pounds. 
 
 Another still larger machine (40-AV model) is shown in 
 Fig. 306. Except for its size it is but little different from 
 the two just described, the main difference being the hydraulic- 
 pressure device, which gives an effective pressure of 5 tons. 
 This machine has a maximum contact area of 3 sq. in. and 
 will weld pieces from 1-J.to 3 in. total thickness; production, 
 15 to 50 welds; throat depth, 6J in.; jaws, 2X4XH in. thick; 
 maximum movement of upper jaw block, 2 in. ; movement 
 with one stroke of lever, f in. ; space possible between jaws, 
 3 in. ; standard ratings, 60 kw. or 86 kva. with 70 per cent. 
 
362 
 
 ELECTRIC WELDING 
 
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ELECTRIC WELDING OF HIGH-SPEED STEEL 
 
 363 
 
 Size of Swi 
 and Fus.e 
 
 
 Size of Switch 
 and Fuses 
 
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364 ELECTRIC WELDING 
 
 power factor; size, 34X60 in. by 79 in. high; weight, 3600 
 pounds. 
 
 For welding tools on these machines the relative thickness 
 of the two parts should be about that shown in Fig. 307. Under 
 ordinary conditions the dimension A should be about one-third 
 of B in order to have the point of the weld nearest the jaw 
 in contact with the high-speed steel, so that the heating effect 
 
 FIG. 308. Pieces Grooved to Make Better Welds with Less Current. 
 
 will be lessened and its fusion point retarded until the low- 
 carbon steel has a chance to heat up properly. 
 
 In order to obtain the best results tools wider than 1 in. 
 and with a recess longer than 1J in. should be grooved as 
 shown in Fig. 308. This reduces the section in actual contact, 
 thereby requiring less current, is easier and quicker to heat 
 and assures a better weld over the entire area of contact. 
 
 In order to assist those who have tool or other butt-welding 
 to do some useful data are given in Table XXVI. 
 
 In Table XXVII is given the proper size of copper wire to 
 use to connect up the various machines mentioned for tool 
 welding. 
 
CHAPTER XVI 
 ELECTRIC SEAM WELDING 
 
 Seam or line welding is the process of joining two over- 
 lapping edges of sheet metal for their entire length without 
 the application of any solder or spelter along the joint. In 
 the Thomson process of lap-seam welding, the heat is produced 
 by passing a large volume of electric current through the 
 edges to be welded by means of a copper roller on one side 
 of the joint and a copper track or horn underneath. In any 
 electrical path, wherever high resistance is interposed, heating 
 will result, and the higher the resistance to the current, the 
 greater will be the heating effect. In the electric lap seam 
 welding machines, the copper roller and horn are good con- 
 ductors and the joint between the edges of the metal to be 
 welded is the point of highest resistance. On this account 
 it is evident that the greatest heating effect will be at that 
 point. As the roller passes over the joint, heating the stock 
 to a plastic state beneath it, pressure is applied by springs 
 on the roller which forces the two edges together as fast as 
 they are heated. Since 20 B. & S. gage or lighter metal heats 
 very rapidly, the pressure and heating can be effected at the 
 same instant of contact by the roller, and it is possible to 
 weld as fast as 6 in. per second. 
 
 The only preparation necessary for seam welding is that 
 the stock must be absolutely clean, that is, free from any traces 
 of rust, scale, grease, or dirt, if a tight, well-appearing joint 
 is desired. If it is not necessary for the joint to be tight, 
 it will not be necessary to have the stock so clean, although 
 heavy scale or rust will obstruct the passage of current, so that 
 little or no heating effect can be secured under these conditions. 
 
 In welding sheet brass of 22 to 30 B. & S. gage, to secure 
 a perfect joint the metal should be carefully pickled and washed 
 to remove all traces of grease and tarnish which tend to prevent 
 
 365 
 
366 ELECTRIC WELDING 
 
 the passage of current across the joint of the edges. The 
 metal should be welded soon after pickling, as, no matter how 
 carefully it may be washed, oxidation is always sure to start 
 very shortly after the brass has been removed from the pickling 
 acid. 
 
 Steel, to be successfully seam welded, should not have a 
 carbon content of over 0.15 per cent., for a higher carbon steel 
 than this has a tendency to crystallize at the point of weld, 
 due to the rapid cooling of the welded portion from the sur- 
 rounding cold meta! After welding, the joint will be found 
 to be about one-third thicker than the single thickness of the 
 metal. It is possible, by applying more pressure, to reduce this 
 finished thickness still more, but it wears more on the copper 
 roller to do so. 
 
 In welding brass, a soft, annealed metal should be used, 
 for although hard-rolled brass can be welded, it does not force 
 the two edges together very much and the finished joint under 
 these conditions is almost twice the original metal thickness. 
 However, with a soft, annealed brass the finished joint will 
 be not over a third greater than the single metal thickness, 
 and by applying sufficient pressure can be reduced down to be 
 not over 10 per cent, thicker. 
 
 The principal advantage of electric seam welding is that 
 no spelter and no flux are required, the metal itself forming 
 its own cohesive properties, which allows great speed in produc- 
 tion. The greatest efficiency of a seam welding machine lies 
 not only in its welding qualities but in the use of a suitable 
 jig to properly hold the work. The jig used should be made 
 so as to enable the operator to place or remove the work in 
 the shortest possible time, since the welding itself is very fast 
 compared with any other known method of making a con- 
 tinuous joint. 
 
 In order that their seam welding machines may operate in 
 every installation with the highest efficiency possible, the Thom- 
 son Electric Welding Co., Lynn, Mass., build them standard 
 only up to a certain point and then design a special holding 
 jig to best fit the work to be done in each individual case. 
 The amount of lap allowed in making lap seam welds is usually 
 about twice the single sheet thickness of the metal. 
 
 The operation of a lap scam welding machine is very sim- 
 
ELECTRIC SEAM WELDING 
 
 367 
 
 pie, once the machine is set for any given piece of work for 
 which a special jig has been built. After placing the piece in 
 the jig and securely locking it there, the operator depresses 
 a foot-treadle which throws in a clutch and starts the copper 
 roller across the work. By the proper setting of adjustable 
 control-stops on the control-rod at the top of the machine, 
 the current is automatically turned on as the roller contacts 
 
 FIG. 309. Model 306 Lap Seam Welding Machine. 
 
 with the overlapping edges of the piece to be welded and is 
 automatically turned off when the roller reaches the end of 
 its stroke; another stop reverses the travel of the roller and 
 brings it back to the starting position. The control-stops may 
 be adjusted to turn the current on or off at any point along 
 the stroke of the roller for doing work with a seam shorter 
 than the maximum capacity of the machine. The roller stroke 
 may be also shortened so that the complete cycle of operation 
 
368 
 
 ELECTRIC WELDING 
 
 will be accomplished in the shortest space of time on seams 
 shorter than maximum seam capacity of any machine. In 
 order to keep the copper roller from overheating in action, 
 water is introduced through its bronze bearings on each side. 
 This same water circulation, also passes through the under 
 copper horn or mandrel and then through the cast-copper 
 secondary of the transformer, so that the machine can be 
 operated continually, 24 hours per day if desired, without 
 overheating. 
 
 Lap Seam Welding Machines. The lap seam welding 
 
 FIG. 310. Details of Welding Roller Head. 
 
 machine, known as Model 306, shown in Fig. 309 will weld 
 a seam 6 in. long in soft iron or steel stock up to 20 gage 
 in thickness, or brass and zinc up to 24 gage thick. This 
 machine will make from 60 to 600 welds per hour, depending 
 on the nature of the work and the quickness with which the 
 pieces can be placed in and removed from the jig. The copper 
 horn is water-cooled and has an inserted copper track on 
 which the work rests. The upper contact consists of a copper 
 roller 6^ in. in diameter, mounted on a knockout shaft sup- 
 
ELECTRIC SEAM WELDING 
 
 369 
 
 ported in water-cooled bearings. Pressure is exerted on the 
 copper roller by means of a series of springs on each side 
 which are adjustable to give the proper tension for various 
 thicknesses of stock. Current control is automatic through 
 a magnetic wall switch carrying the main current. The latter 
 is controlled from a mechanical switch which is thrown in or 
 out by the action of the roller-carrying mechanism as it starts 
 
 FIG. 311. Thomson No. 318 Lap Seam Welding Machine. 
 
 and completes the stroke for which it is set. Standard wind- 
 ings are for 220-, 440-, and 550-volt, 60-cycle, alternating cur- 
 rent. Current variation for different thicknesses and kinds 
 of stock, is effected through a regulator which gives 50 points 
 of voltage regulation. A variable-speed J-hp. motor gives a 
 wide variation in the speed with which the roller may be fed 
 over the work. The standard ratings for the machine are 
 15 kw. or 25 kva., with 60 per cent, power factor. This 
 
370 
 
 ELECTRIC WELDING 
 
 machine covers 32X96 in. floor space, is 68 in. high and weighs 
 2750 Ib. 
 
 A close-up view of the type of roller-carrying head used 
 on all the lap seam welding machines, is shown in Fig. 310. 
 In this view the roller is shown operating between the clamping 
 bars of a special holding jig on the horn. As the roller itself 
 occasionally requires smoothing off around its contacting sur- 
 face, its bearing has been designed to knock out quickly so 
 
 FIG. 312. Large Size, No. 324, Lap Seam Welding Machine. 
 
 that removal and replacement of the roller is very simple and 
 easy to accomplish. The cleaner the stock being welded is 
 kept, the longer a roller will operate without requiring smooth- 
 ing off, as dirt and scale on the stock cause a slight sparking 
 as the roller passes along, which tends to pit up its contact 
 surface. 
 
 The machine shown in Fig. 311, known as Model 318, is 
 a larger and heavier machine than the one previously described 
 
ELECTRIC SEAM WELDING 
 
 371 
 
 and will weld a lap scam 18 in. long on the same gages of 
 metal quoted. Another very similar but smaller machine 
 (Model 312) is also made for welding seams up to 12 in. 
 
 In Fig. 312 is seen a considerably larger machine, Model 
 324, capable of welding a lap seam up to 24 in. in length. 
 The production is from 30 to 120 welds per hour. The machine 
 covers a floor space of 36X90 in., is 72 in. high, and weighs 
 3500 Ib. All other specifications are the same as given for 
 Fig. 309. 
 
 Examples of Holding 1 Jigs. The machines shown may be 
 fitted with numerous forms of holding jigs from the simple 
 
 FlG. 313. Oil Stove Burner Tubes Before and After Welding. 
 
 bar clamps shown on the horns in Figs. 311 and 312, to various 
 more complicated forms, some of which may be mounted on 
 the knee below the horn or bolted direct to the face of the 
 machine column. 
 
 The small oil stove burner tubes shown in Fig. 313 lend 
 themselves nicely to the seam welding process. Cylindrical 
 pieces such as the shell tubes for automobile mufflers shown 
 in Fig. 314, need a rather elaborate holding jig. A machine 
 fitted up for this work is shown in Fig. 315. To insert a 
 muffler shell into this jig the hinged end is swung outward 
 and downward; the two halves of the holder are spread apart 
 by pressing down on the left-handle treadle; the shell is then 
 
372 
 
 ELECTRIC WELDING 
 
 thrust into the holder; the treadle is released, which allows 
 the holder sides to be pressed in by the springs and hug the 
 muffler shell around the horn of the machine, with the edges 
 overlapping enough for the weld; the end gate is then closed 
 and the welding roller started over the seam. The principal 
 function of the gate is to hold the muffler shell square in the 
 jig and prevent it behig pushed out by the welding roller. 
 
 FIG. 314. Seam Welded Automobile Muffler Tubes. 
 
 A jig for holding large cans is shown in Fig. 316. The 
 side clamps of this jig are operated by means of the lever 
 shown at the left. An end gate, shown open, is used in the 
 same way as in the muffler shell jig. Work of this kind is 
 of course much slower than with a smaller jig, yet it is faster 
 than by any other process of closing the scams. 
 
ELECTRIC SEAM WELDING 
 
 373 
 
 Bucket bodies are held as shown in Fig. 317. The holding 
 jig is made to slide in a channel bolted to the machine knee. 
 The jig is slid back clear of the horn and, with the gate in 
 the flaring end open, the bucket blank is inserted. The gate 
 
 FIG. 315. Holding Jig for Automobile Muffler Tubes. 
 
 is then closed by means of the handle, the jig and work is 
 pushed over the horn to a stop, and the weld is made as usual. 
 Another application of seam welding, is to use it for welding 
 the ends of strip stock together, end to end, so as to facilitate 
 continuous passage of the strip through the dies of a punch 
 press. A machine fitted up for this work is shown in Fig. 318. 
 
374 ELECTRIC WELDING 
 
 The ends of the two strips to be welded are inserted in the 
 jig from opposite sides and the edges brought together. The 
 pieces are then clamped by means of the two levers shown in 
 front of the jig, which operate eccentrics over the clamping 
 
 FIG. 316. Holding Jig for Large Sheet Metal Cans. 
 
 plates. The welding roller is then run over the ends as in 
 other work of this kind. 
 
 Flange seam welding differs from lap seam welding in 
 that instead of the metal being lapped a slight fin or flange 
 is formed along the edges of the metal parts, the flanges being 
 welded together and practically eliminated in the process. This 
 
ELECTRIC SEAM WELDING 
 
 375 
 
 Class of welding is especially adapted to the manufacture of 
 light gage coffee and teapots spouts or similar work. 
 
 A machine built especially for flange seam welding, known 
 
 FIG. 317. Jig for Holding Bucket Bodies. 
 
 as Model 26, is shown in Fig. 319. The work being done is 
 the welding of the two halves of teapot spouts. In the operation 
 the two halves of the spout are clamped securely in a special 
 copper jig, Fig. 320, which has been carefully hand-cut to 
 
376 
 
 ELECTRIC WELDING 
 
 fit the halves of the spout perfectly on the entire contacting 
 area. The jig is pushed around on the flat copper table, which 
 constitutes the top of the welding machine, so that the seam 
 of the edge to be welded is allowed to ride along the small 
 
 FIG. 318. Jig for Welding Ends of Metal Strips Together. 
 
 power-driven copper roller which is mounted on a vertical 
 shaft, as illustrated in Fig. 321. The halves which are welded 
 by this process must be blanked out by special steel dies to 
 give the correct amount of fin or flange on each edge. This 
 
ELECTRIC SEAM WELDING 
 
 377 
 
 fin is heated to the plastic stage by contact with the roller 
 and the slight pressure applied not only forces the metal of 
 the two fins to cohere but also forces the projection into a 
 level with the outer surface of the spout, thus giving a finished 
 job direct from the welder which is smooth enough without 
 
 FIG. 319. Machine for Flange Seam Welding. 
 
 any grinding to be ready for the enamelling or agate-coating 
 process. 
 
 The secret of success of this work lies wholly in the proper 
 preparation of not only the copper holding-dies, but also the 
 steel flanging and forming dies. A finished spout, just as it 
 
378 
 
 ELECTRIC WELDING 
 
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 oooot^t*'otou> o* s <s< o 
 
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ELECTRIC SEAM WELDING 
 
 379 
 
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 P *o 
 
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380 
 
 ELECTRIC WELDING 
 
 FIG. 320. Jig for Holding Teapot Spouts for Welding. 
 
 FIG. 321. Diagram of Flange Seam Welding Operation. 
 
 FIG. 322. A Finish Welded Teapot Spout. 
 
ELECTRIC SEAM WELDING 381 
 
 comes from the welding machine, is shown in Fig. 322. The 
 welded seam is barely visible. 
 
 In order to assist those who have welding jobs to do, to 
 calculate the current cost on various jobs, Table XXVIII is 
 given. This table shows the approximate current consumption, 
 and multiplying the rate given by the local rate charged, the 
 cost of 1000 welds can be easily ascertained. 
 
 Table XXIX is very convenient for ascertaining the size 
 of copper wire needed to connect the different machines men- 
 tioned to the main source of current supply. 
 
CHAPTER XVII 
 
 MAKING PROPER RATES FOR ELECTRIC WELDING 
 AND THE STRENGTH OF WELDS 
 
 The uncertainty which seems to exist regarding electric 
 welding rates among central-station interests, says S. I. 
 Oesterreicher in Electrical World, is no doubt due to the indif- 
 ference of the welding industry, which during a long period 
 in the past did not assist those affected by the rates as much 
 as its unquestionable duty would have suggested. 
 
 While welding installations of only comparatively small 
 sizes had to be considered say from 25 to 100 kva. no great 
 harm was done by such tactics to either interest. However, 
 with the installation of large equipments and the operation 
 of large unit welding machines, central stations suddenly 
 experienced disturbances upon their lines and in their stations, 
 which were anticipated but partly and were blamed entirely 
 upon the welding equipment. Thus, to protect themselves, 
 central-station interests launched into a partially retroactive 
 policy, greatly to the detriment of the welding industry as 
 a whole. 
 
 Since welding installations of several thousand kva. capacity 
 are not unusual, it is proper that all points of doubt should 
 be considered as broadly and fairly as possible, and a far- 
 reaching co-operative policy inaugurated. The revenue from 
 such large installations may easily reach several thousand 
 dollars a month. It is therefore obvious that, from a purely 
 commercial standpoint, a welding load is a very desirable 
 constant source of income to the central station. 
 
 Looking at the reverse side, it should be recalled that cen- 
 tral-station engineers, on account of past sad experiences, had 
 jumped to the following conclusions : 
 
 1. That a welding installation is a very unreliable metering 
 proposition. 
 
 382 
 
MAKING PROPER RATES FOR ELECTRIC WELDING 383 
 
 2. That it has a poor load factor. 
 
 3. It has a constantly fluctuating load varying between 
 extreme limits, and 
 
 4. It has a bad power factors 
 
 The first important point is, no doubt, the metering. The 
 time-honored opinion on one side that, due to the short period 
 involved, an integrating wattmeter does not respond quickly 
 enough, is contradicted by the claim on the other side that 
 the deceleration of the meter disk compensates for the lagging 
 acceleration. As far as the writer is aware, not the slightest 
 positive proof has been offered to support either contention. 
 Considering for instance a 200-volt, 300-amp., single-phase, 
 two-wire wattmeter, whose disk at full load makes 25 r.p.m., 
 and assuming -the total energy consumption to be integrated 
 within 0.2 second, it will be found that to register correctly 
 the meter disk has to travel about 0.08 of a revolution. It is 
 scarcely possible that by merely looking upon a meter disk 
 any one could guess within 100 per cent the actual travel 
 during such a short time interval. A stop watch will scarcely 
 be of any assistance; neither will a cycle recorder with an 
 ammeter and voltmeter check be of any value, since no instru- 
 ment is of such absolute dead beat as to come to rest from 
 no load to full load within 0.2 second. Such methods therefore 
 are of no value in ascertaining the behavior of a wattmeter 
 under sudden intermittent heavy loads. 
 
 The next step of the metering proposition was to take the 
 rated energy consumption of the welding machine as given by 
 the manufacturer, assume a certain load factor, calculate from 
 these data the energy consumption, correct for the power factor 
 and check the answer periodically on the meter dial. The 
 result obtained on the meter was usually a constantly varying, 
 lower energy consumption than calculated, and no doubt this 
 was the cause of the great distrust of the meter. This method 
 is worse than no check at all, and it is so for the following 
 reasons : 
 
 1. The energy consumption at a welder depends upon the 
 welding area of the metal, but is not a proportionate variable. 
 That is, all other factors being the same, two square inches 
 of a certain weld do not consume twice as much energy as 
 one square inch does. Fig. 323 shows this fact plainly. It 
 
384 
 
 ELECTRIC WELDING 
 
 is also of common knowledge that on a spot welder the area 
 of the weld varies from weld to weld just as much as the 
 electrode contact area does. Assuming an electrode at the start 
 as Vie in- diameter at the tip, after about 200 welds it might 
 be anything from J in. to 5 /i 6 in- diameter, thus gradually 
 increasing its contact area anywhere from 75 per cent to 175 
 per cent. 
 
 2. On butt welders the energy consumption does not depend 
 
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 2680 
 
 1600 
 
 1600 
 
 1 
 
 1400 
 
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 E 300 
 
 
 600 
 
 X 
 
 S- 
 
 w 400 
 
 200 
 
 t\ 
 
 
 
 
 
 
 
 
 
 
 
 
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 2144 v> 
 75 
 
 1876 3 
 
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 vo 
 
 1608 i" 
 
 c 
 
 1340 
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 1072 | 
 
 E 
 
 804 x 
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 u 
 
 536^ 
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 v\ 
 
 
 
 
 
 
 
 
 
 
 
 
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 / 
 
 
 
 
 
 
 
 
 
 
 
 
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 y 
 
 
 
 
 
 
 
 
 
 
 
 
 Welding Area of Iron in s<\. in. 
 
 FIG. 323. Energy Consumption of Resistance Welding for Commercial 
 Grades of Sheet Iron. 
 
 upon the size of the weld alone, but also upon the clamping 
 distances. Fig. 324 gives some information about the influence 
 of variable clamping distances upon the energy consumption 
 of welding machines. On a butt welder, the clamping distances 
 increase with the gradual wear of the electrode ; thus the above 
 spot welder conditions are duplicated on butt welders also. 
 3. If no compensation is made to vary the impressed ernf. 
 
MAKING PROPER RATES FOR ELECTRIC WELDING 385 
 
 of the welder and this is never done then the time must 
 vary from weld to weld according to the condition of the 
 electrode. If the time is changing constantly, the assumed 
 load factor changes correspondingly; thus there are three con- 
 stantly changing factors in the estimated energy consumptions, 
 beyond any reasonable approximation of the actual facts. 
 
 A more reliable method would be a periodic oscillograph 
 test, but this method is rather complicated and expensive and 
 could be done only by large central stations which have both 
 the equipment and the trained personnel for such work. 
 
 Such tests, once they are made for certain types of welders 
 
 3.5 4.0 
 Inches 
 
 1.0 1.5 2.0 2.5 3.0 
 Clamping Distance 
 
 ,FiG. 324. Effect of Clamping Distance Between Electrodes Upon Time 
 and Energy Demand. Area, 0.25 Sq. In. 
 
 and work, will give excellent data from which to check the 
 actual behavior of the standard type of wattmeter. If such 
 comparisons are made, it will be found that the integrated 
 energy consumption of the wattmeter will be larger than the 
 oscillograph test indicates. It is not intended to claim that 
 the wattmeter registers "fast. " Laboratory tests are usually 
 made by skilled men, who before the test carefully ascertained 
 all important factors entering into the test, as area of weld, 
 condition of electrodes, welder, emf., cleanliness of material, 
 etc., whereas under normal operating conditions almost no 
 attention is paid by the operator to these considerations. In 
 fact, if the operator works on a piecework or bonus basis, he 
 will conceal as much as possible all discrepancies which have 
 
386 ELECTRIC WELDING 
 
 a tendency even temporarily to curtail his earnings. The result 
 of his policy has a very important effect upon the wattmeter. 
 
 Summing up the metering proposition and speaking from 
 experience on large welding installations with capacities over 
 250,000 sq. in. of welding per month, where ten to fifteen butt 
 welding machines are constantly thrown on or off the supply 
 circuit, it is safe to claim that in such installations the standard 
 alternating-current integrating wattmeter is on the job. 
 
 The Load Factor. The present-day tendency in resistance 
 welding practice is to perform the weld as quickly as possible 
 without injury to the metal, but fast enough to prevent im- 
 perfection at the weld. Having in mind large welders with 
 5 to 15 sq. in. weld capacities, this tendency will give a unit 
 load factor not much over 10 per cent per welder. From the 
 central-station viewpoint, this factor is certainly very low and 
 undesirable. 
 
 However, two important circumstances alter the condition 
 considerably. The first point is that in large installations one 
 large welder will not suffice to do all the required work, there- 
 fore several will have to be installed. Owing to the big energy 
 demands these large welders never operate simultaneously. 
 While one welds the next is cleaned, the third is prepared, the 
 fourth is waiting for the signal to weld, etc. ; thus the load 
 factor of the installation as a whole is considerably over 10 
 per cent and nearer to 20 per cent. Another natural circum- 
 stance of large installations is the fact that not all work requires 
 large welders. There are usually ten to fifteen smaller welders 
 installed, of which 30 per cent might work intermittently with 
 the larger welders. Thus it will be seen that the load factor 
 is bad only in small installations connected to small central 
 stations, while large installations, which necessarily must 
 receive their supply of energy from comparatively larger cen- 
 tral plants, have rather a good aggregate load factor, reaching 
 well up to 25 to 30 per cent. 
 
 Another point for consideration is the fact that, owing to 
 its temperature, large work cannot be handled immediately 
 after welding. The work must cool off before additional opera- 
 tions can be performed upon it. The cooling takes some time. 
 In several instances it was found desirable to shift the working 
 hours of the welding crew several hours ahead or behind the 
 
MAKING PROPER RATES FOR ELECTRIC WELDING 387 
 
 working hours of the rest of a factory, for the sole reason that 
 there should be on hand sufficient cool welded work for the 
 successive manufacturing steps. If this time-shifting is selected 
 to coincide with the low-point period of the load factor of a 
 central station, then there results an actual all-around improve- 
 ment. For this the welding installation should be entitled to 
 a certain proportionate consideration. 
 
 Maximum Demand. Owing to the instantaneous severity 
 of a welding load, demand upon a supply station seems to be 
 of considerable importance. However, the shifting of a load 
 factor toward an off-load period, as described, will certainly 
 take the severest effects off the system. Under such conditions 
 regulation of the supply system suffers only in small plants, 
 and only in places where lighting and power loads are fed 
 from the same mains 
 
 But large welding installations are usually direct-connected 
 through transformer banks to the station buses, where the 
 fluctuating character of the welding load will be almost negli- 
 gible and certainly will not affect the regulation of a system 
 in a degree commensurate with the size of the connected weld- 
 ing installation. Of course in all these discussions it is assumed 
 that the station apparatus, transformers and supply feeders 
 are properly selected, with equipment properly calculated to 
 fit the particular welding load. In the past this has not always 
 been the case, and this is one of the causes of so many different 
 maximum demand charges. 
 
 The ratio which the maximum demand should bear to the 
 connected load will always remain a local issue between 
 producer and consumer. The ratio should, however, be made 
 to depend on the average kilovolt-ampere energy demand of 
 all the welders (and not on their rated capacities as given 
 by the manufacturer) and of the rated capacity of the primary 
 supply installation. If the welding customer bears a part of 
 the installation charges caused by larger transformers and 
 larger supply mains, he should benefit by the resultant mutual 
 advantages. However, no demand charge should be based 
 upon a mixed welding and motor load supplied from a common 
 primary installation. The importance of this claim will be 
 more evident if it is stated that by separating a certain mixed 
 welding and motor circuit, and by installing an additional 
 
388 ELECTRIC WELDING 
 
 100-kw. equipment, the maximum-demand charge in a single 
 supply circuit in one month was reduced over $200. 
 
 To be sure that no more disturbing overloads are thrown 
 upon the line than have been contracted for, overload relays, 
 time clocks and maximum-demand indicators will be found 
 sufficiently reliable for all honest purposes on both sides of 
 the controversy. 
 
 Proper grouping of the single-phase welding loads upon 
 a three-phase supply system will give perfect satisfaction in 
 almost all installations but those of small size. 
 
 Power Factor. So much has been said and so much worry 
 caused about the poor power factor of a welding installation 
 that it is now universally accepted that the power factor is 
 bad, and nothing further is done about it. The outstanding 
 feature about this condition is that the central stations, in a 
 most unfortunate moment, decided to t( penalize" the power 
 factor. It is not the charge for the condition, but the adoption 
 of the word for the charge, which makes the customer balk 
 and is the cause of no end of distrust toward the welding 
 machine. The word "penalty" conveys to the lay mind the 
 impression that a poor power factor exists only with welding 
 installations, and naturally the conclusions are not nattering 
 for the welding equipment. 
 
 No attempt is made here to describe the well-known methods 
 of improving the power factor of a welding installation with 
 synchronous apparatus. The adoption of such methods is more 
 of a commercial than an engineering problem. Upon investiga- 
 tion it will be found that, with few exceptions, it is cheaper 
 to pay for the poor power factor than to invest in additional 
 apparatus. However, the average power plant usually has, 
 besides a welding installation, a number of other consumers, 
 the effects of whose poor power factor are felt in considerable 
 measure at the generators. If all such sources are investigated 
 and segregated upon one common bus, together with a welding 
 load, it might be found that either a synchronous or static 
 apparatus would more than pay for itself, if installed at the 
 proper place. 
 
 If this fact is explained to a welding customer, there can 
 be no doubt that he will be only too eager to bear a certain 
 proportion of the investment for a special apparatus and thus 
 
MAKING PROPER RATES FOR ELECTRIC WELDING 389 
 
 secure for himself a better rate for the consumed energy. With 
 proper co-operation between the central station and the welding 
 customer on all these points of mutual interest, much misunder- 
 standing and distrust could be eliminated, benefiting all parties 
 concerned in the welding industry. 
 
 FILLET AND SPOT WELDED 
 
 FILLET WELDED 
 
 Y& 
 
 RIVETED AND FILLET WELDED 
 
 SPOT WELDED 
 12" 
 
 &r 
 
 3/4 Rivets 
 
 /2 
 
 E Pfr 
 
 
 -f 4- .I" 
 
 
 -^-^ 
 
 
 
 : 4 !'... 
 
 
 : 
 
 RIVETED JOINT 
 FIG. 325. Welded and Riveted Joints. 
 
 Strength of Resistance Welds. In some of its applica- 
 tions, spot welding affords a method of preliminary joining 
 ship hull plates, after which the required additional strength 
 is obtained by arc welding. The Welding Research Sub-Com- 
 mittee made some progress in comparing combined spot and 
 
390 
 
 ELECTRIC WELDING 
 
 arc welds, and combined rivet and arc welds with riveted, 
 spot- welded and arc-welded joints. It is not a question in 
 such an investigation, of spot versus arc welding, but of spot 
 and arc welding. 
 
 According to Hobart, test specimens are made up of the 
 following combinations : 
 
 (a) Spot and fillet welds (two samples made) 
 
 123456 
 
 7 8 9 1O 
 
 
 
 FIG. 326. Spot-Welding Tests on Hoop Iron. 
 
 (b) Fillet welds, made by welding fillets about two inches 
 
 in length at the ends of overlapping plates (two 
 samples made) 
 
 (c) Rivet and fillet welds (one sample made) 
 
 (d) Spot welds, made by welding two spots approximately 
 
 one inch in diameter, on the plates (two samples 
 made) 
 
 (e) Riveted joint, made by riveting a X4X12 in. plate 
 
 with two plates JX4X16 in., using two f in. rivets 
 and a four inch plate lap (one sample made) 
 
MAKING PROPER RATEG FOR ELECTRIC WELDING 391 
 
 The way these plates were fastened is illustrated in Fig. 
 325. The results of the tests were as follows : 
 
 (a) Spot and fillet weld ultimate load 50,350 Ib. 
 
 (b) Fillet welds ultimate load 37,000 Ib. 
 
 (c) Eivet and fillet welds ultimate load 35,000 Ib. 
 
 (d) Spot welds ultimate load 28,000 Ib. 
 
 (e) Riveted joint ultimate load 13,000 Ib. 
 
 Spot- Welding Tests on Hoop Iron. The Thomson Co. made 
 up ten samples of spot-welded, riveted, butt-welded and plain 
 pieces of hoop iron, and had them tested in the Lunkenheimer 
 laboratory. The pieces after testing are shown in Fig. 326. 
 
 The results were as follows: 
 
 No. 1. Spot- welded in one place broke at weld at 1,625 pounds. 
 
 No. 2. Spot-welded in two places, also two rivets broke at rivets at 
 
 1,555 pounds. 
 No. 3. Spot-welded in three places: broke outside weld at 2,715 pounds. 
 
 (Notice elongation of metal.) 
 No. 4. Spot-welded in three places, also three rivets broke at rivets at 
 
 2,055 pounds. 
 
 No. 5. Solid lap-weld broke outside weld at 2,720 pounds. 
 No. 6. Butt-welded broke at weld at 2,555 pounds. 
 No. 7. Spot-welded in one place, and riveted once broke at rivet at 990 
 
 pounds. 
 
 No. 8. Solid lap-weld broke at weld at 2,425 pounds. 
 No. 9. Spot-welded in two places broke at weld at 2,275 pounds. 
 No. 10. Plain piece of hoop iron, not welded pulled apart at 2,690 pounds. 
 
 Taking the average of the breaking points of the three 
 pieces, 3, 5 and 10, that broke in the pieces themselves, we 
 get approximately 2700 Ib. as the strength of the hoop iron. 
 This furnishes a basis for percentage calculations if such are 
 desired. By grouping six of the tests, we get the following 
 results for comparative purposes: 
 
 Test No. 1. One Spot-weld: broke at 1,625 pounds. 
 Test No. 7. One Rivet: broke at 990 pounds. 
 
 The weld stood over 60 per cent more than the rivets 
 Test No. 9. Two Spot-Welds: broke at 2,275 pounds. 
 Test No. 2. Two Rivets: broke at 1,555 pounds. 
 
 The weld stood over 60 per cent more than the rivets. 
 Test No. 3. Three Spot-Welds: broke outside weld at 2,715 pounds. 
 Test No. 4. Three Rivets: tore apart at 2,055 pounds. 
 
392 
 
 ELECTRIC WEEDING 
 
 Strength of Spot- Welded Holes. It sometimes happens that 
 a hole will by mistake be punched in a plate where it is not 
 needed. The spot welder can be used to plug such holes and 
 make the plate as strong as, or stronger than, it was originally. 
 It is first necessary to make a plug of the same material as 
 the plate which will fit in the hole and which is slightly longer 
 than the plate is thick. The length required will depend on 
 the snugness of the fit of the plug in the hole; there should 
 be enough metal in the plug to a little more than completely 
 fill the hole. The plate is placed in the welder with the hole 
 which is to be filled centered between the electrodes, the plug 
 is placed in the hole, the electrodes brought together upon it, 
 
 J?IG. 327. Sample Plates with Holes Plugged by Spot- Welding. At the 
 Eight Is Shown a Plate with Plug in Place Previous to Welding. 
 
 and upon the application of pressure and current the plug 
 will soften, fill the hole, and weld to the plate. 
 
 Fig. 327 shows, at the extreme right, a piece of ^-in. plate 
 with a punched hole which is to be plugged, and the plug in 
 place previous to welding. The three pieces at the left of 
 the photograph have the plugs welded in place. A fact which 
 the illustration does not bring out very clearly is that the 
 surface, after the plug is fused in, is practically as smooth as 
 the remainder of the plate, the maximum difference in thick- 
 ness between the plugged portion and the remainder of the 
 plate being not more than 1 / 32 in. on a J-in. plate. 
 
 That there is a real and complete weld between the plug 
 and the plate is shown by Fig. 328. The four samples illus- 
 
MAKING PROPER RATES FOR ELECTRIC WELDING 393 
 
 trated were placed in a testing machine and broken by longi- 
 tudinal pull, with the interesting result that not one of the 
 three plugged plates broke through the weld. The sample at 
 the right was broken to give an indication of the strength 
 of the samples after punching and before welding. Two sam- 
 
 I Pi mm 
 i 
 
 FiG. 328. Plates Shown in Fig. 327 After Pulling in the Testing Machine. 
 Note That All Welded Plates Broke Outside the Weld. 
 
 TABLE XXX. 
 
 No. of 
 Sample 
 
 Description 
 of Sample 
 
 Sec- 
 tion 
 In. 
 
 Tensile 
 Strength 
 Lb. 
 
 Location 
 of 
 Fracture 
 
 1 
 
 Punched &-in. dia- 
 
 2 by 
 
 59,320 
 
 Outside 
 
 
 meter hole and 
 
 1 A 
 
 
 weld 
 
 
 plugged by welding 
 
 
 
 
 2 
 
 Punched -&-in. dia- 
 
 2 by 
 
 59,320 
 
 Outside 
 
 
 meter hole and 
 
 H 
 
 
 weld 
 
 3 
 
 plugged by welding 
 Punched i^-in. dia- 
 
 2 by 
 
 59,350 
 
 Outside 
 
 
 meter hole and 
 
 1 A 
 
 
 weld 
 
 
 plugged by welding 
 
 
 
 
 4 
 
 Punched -&-in. dia- 
 
 2 by 
 
 31,590 
 
 Through 
 
 
 meter hole but not 
 
 1 A 
 
 
 hole 
 
 
 plugged 
 
 
 
 
 5 
 
 Original bar, not 
 
 2 by 
 
 59,230 
 
 Through 
 
 
 punched 
 
 H 
 
 
 center 
 
 6 
 
 Original bar, not 
 
 2 by 
 
 59,000 
 
 Through 
 
 
 punched 
 
 H 
 
 
 center 
 
394 ELECTRIC WELDING 
 
 pies (not shown) from the same bar but without the punched 
 holes were pulled to find the original strength of the material. 
 The results are given in Table XXX. 
 
 It is interesting to note that the average of the breaking 
 point of the three samples punched and plugged was 59,330 
 lb., whereas the average for the two samples not punched was 
 59,115 lb., or 115 lb. less. This proves that there was no weak- 
 ening of the surrounding plate, due to the weld. That the 
 ductility of the welded section was somewhat decreased is 
 shown by the photographs of the samples after pulling. 
 
 The actual welding time required for plugging a hole in 
 a plate is from five to ten seconds. Of course, it is necessary 
 to have a plug of the proper size, but a variety of plugs, of 
 all the standard rivet hole diameters and of lengths suitable 
 for the various thicknesses of plates, could be made up and 
 
 FIG. 329. Straight Rods Spot-welded to Angle Iron and then Bent by 
 Hammer Blows, the Angle Being Supported only by the Un welded Flange. 
 
 kept in stock in the yard. The method described should prove 
 a valuable means of salvaging material which otherwise might 
 have to be scrapped. 
 
 Strength of Rods Mash- Welded to Angle Iron. While no 
 figures are available, the illustration Fig. 329 will give an 
 idea of the strength of welds where rods are mash-welded to 
 angle iron or plate. Three straight iron rods were welded 
 to an angle iron and then hammered over with a sledge, as 
 shown. This is a very severe test of a weld. 
 
 Strength of Electric Resistance Butt- Welds. According to 
 Kent, tests of electric resistance butt-welded iron bars resulted 
 as follows: 
 
 32 tests, solid iron bars, average .52,444 lb. 
 
 17 tests, electric butt-welds, average 46,836 lb. 
 
MAKING PROPER RATES FOR ELECTRIC WELDING 395 
 
 This is an efficiency of 89.1%. 
 
 Presumably the welds were turned to the size of the bars, 
 although Kent does not say so. 
 
 In a number of tests on draw-bench mandrels the following 
 results were obtained. The mandrels consisted of one piece 
 of in. dia., 30-40 point carbon steel, welded on to another 
 piece of f dia., 110 point carbon Carnegie electric tool steel 
 No. 4. The low carbon ends were drilled and threaded to 
 receive the stud of the bench rod, and the high carbon ends 
 were upset, machined, and used as working heads. Six sam- 
 ples of each kind of steel were prepared and sent to the Thom- 
 son Electric Welding Co. of Lynn, Mass., to be welded. 
 
 After welding the mandrels were subjected to the follow- 
 ing heat treatments and operations: 
 
 1. Head-end annealed after upsetting. 
 
 2. Head-end machined, and hardened by quenching in 
 
 water. 
 
 3. Mandrels worked on draw benches until worn out or 
 
 broken. 
 
 4. Entire length of mandrels heated to 1450 F. and cooled 
 
 in air. 
 
 5. Mandrels subjected to tensile test to destruction. 
 Mandrel No. 1. Pulled 5125 ft. of 1X-H2 in. to JX.107 in., 
 
 17 point carbon. Rather heavy pull. Broke stud once, and used 
 again after replacing same. Pulled to destruction in standard 
 testing machine, and failed 2J in. below weld on low carbon end, 
 at a stress of 59,000 Ib. per sq. in. Weld stronger than low 
 carbon round. 
 
 Mandrel No. 2. Pulled 3360 ft, of ! 3 /i 6 X.46 in. to 3 / 4 X.38 
 in., 17 point carbon. Not badly worn at end of load. Pulled 
 to destruction in testing machine, and failed 1 in. below weld 
 on low carbon end, at a stress of 58,800 Ib. per sq. in. Weld 
 stronger than round of 30-40 point carbon of same cross-section. 
 
 Mandrel No. 3. Pulled 2400 ft. of 1X-H2 in. to JX.107 
 in., 17 point carbon. Broke at stud and replaced by another 
 mandrel. Pulled to destruction in testing machine, and failed 
 on weld at stress of 58,000 Ib. per sq. in. Weld 98% efficient, 
 referred to mandrel No. 1. 
 
 Mandrel No. 4. Pulled 2250 feet of 1 3 / 4 X.200 in. to 
 lVioX-200 in., 17 point carbon. In good shape at end of load. 
 
396 ELECTRIC WELDING 
 
 Pulled to destruction in testing machine and failed on weld, 
 at a stress of 56,900 Ib. per sq. in. Weld 96% efficient, referred 
 to mandrel No. 1. 
 
 Mandrel No. 5. Pulled 402 ft. of 1X.H2 in. to JX-108 in., 
 17 point carbon. Broke off at stud of rod, tube being unduly 
 oversize. Pulled to destruction in testing machine, and failed 
 on weld at a stress of 53,700 Ib. per sq. in. Weld 91% efficient, 
 referred to mandrel No. 1. 
 
 Mandrel No. 6. Mandrel broken at thread on first tube. 
 Tube over-size. Mandrel lost. 
 
 Conclusion. Out of five mandrels subjected to a tensile 
 test to destruction after being worked, on the benches, two 
 show that the weld is stronger than the 30-40 point carbon 
 round solid rod, and the other four showed efficiency of 91% 
 to 98%, referred to 59,000 Ib. per sq. in. The maximum 
 required efficiency is not over 70%. Therefore the mandrels 
 passed all requirements for strength and service. 
 
 Strength of High Carbon Steel Welds. In order to throw 
 some light upon the chemical and physical changes induced by 
 the welding process, pieces of 0.97 per cent carbon drill steel, 
 of | in. diameter, were studied after butt welding, writes E. E. 
 Thum in Chemical and Metallurgical Engineering, Sept. 15, 
 1918. Test pieces of the original stock and of both annealed 
 and unannealed welds were made by mounting in a lathe, re- 
 moving the excess metal of the fin, and then turning or grinding 
 a short length of the bar accurately to a diameter of J in., 
 with the weld in the center of the turned portion. In the 
 unannealed welds, the turned portion was but J in. in length 
 in order that the failure would be forced to occur within the 
 portion of the bar altered in constitution by the welding heat. 
 Tension tests of the unannealed welds showed, in all cases, a 
 failure with little or no necking occurring at the end of the 
 turned portion that is to say, farthest from the weld and in 
 the softest portion of the test piece. The strength this de- 
 veloped was much higher than even the strength of the original 
 steel, and it is clearly evident that all parts of this weld have 
 a higher ultimate strength than the original bar. The average 
 results of the tension tests follow: 
 
MAKING PROPER RATES FOR ELECTRIC WELDING 397 
 
 Ultimate Contraction Elongation 
 
 Strength Lb. in Area? in In. 
 
 per Sq. In. Per Cent Per cent 
 
 Original tool steel 114,100 12 10 
 
 Unannealed weld 158,700 2 3 
 
 Weld annealed at 750 C. (1382 P.).. 100,800 24 16 
 
 In the annealed bars failure always occurred at the weld, 
 accompanied by considerable necking, strictly limited to the 
 close proximity of the point of failure. 
 
 The results of a series of tests on butt- and spot-welds made 
 by G. A. Hughes, electrical engineer of the Truscon Steel Com- 
 pany, Youngstown, Ohio, were reported as follows: 
 
 TESTS MADE ON BARS OF SOFT STEEL, 1 IN. SQ., BUTT-WELDED AND 
 
 MACHINED TO THE SIZE OF THE BAR. 
 
 Test No. Volts Amps. Kw. Power Factor 
 
 1 220 220 40. 91 
 
 2 220 220 40. 91 
 
 3 220 210 39. 84 
 
 4 218 210 39.5 86 
 
 5 220 210 39. 84 
 
 All tension tests were pulled at a speed of y 2 in. per min. 
 Nos. 1, 2 and 3 were pulled, while Nos. 4 and 5, were sheared. 
 On the different tests, No. 1 failed in the weld at 48,800 lb.; 
 No. 2 failed in the weld at 52,300 lb. ; No. 3 failed back of the 
 weld at 50,100 lb. ; No. 4 failed at 51,500 lb. and No. 5 at 
 50,300 lb. 
 
 These tests indicate that the ultimate shearing strength of 
 such a weld closely approaches the ultimate tensile strength. 
 
 Pieces of soft steel, 3 / 16 in. thick and 5 in. wide, with an 
 ultimate tensile strength of 56,150 lb., were butt-welded and 
 pulled with the following results: 
 
 Test No. Manner of Failure Lb. . Per Cent 
 
 1 % in plate and % in weld 51,000 91 
 
 2 In plate just back of weld 52,000 93 
 
 3 " " " " " " 53,400 95 
 
 4 " " " " " " 52,000 93 
 
 5 " " " 46,100 82 
 
 6 ft .it i< tt ii n 51,900 93 
 
 On six samples of spot-welded single lap-joint sheets of 14 
 gage steel, 3 in. wide, welded with a 5 /i in - s P ot ' the average 
 at which the welds pulled out, was 4480 lb. 
 
398 ELECTRIC WELDING 
 
 The ultimate tensile strength of a piece of plate of 14 gage, 
 was 64,500 per sq. in. The ultimate shearing load per weld 
 (two spots with an area of 0.0742 sq. in. each) averaged 8942 
 Ib. Approximate total welded area, 0.1484 sq. in. This gives 
 an ultimate shearing strength for 1 sq. in. of weld, of about 
 60,200 Ib. On steel % in. thick and 2 in. wide, welded with 
 a spot having an area, measured with a planimeter, of 0.476 
 sq. in., the failure under pull was at 34,650 Ib. Examination 
 of the welds showed them to be under both a tensile and a 
 shearing action. A piece of the same steel tested for ultimate 
 strength, failed at eftjSOO Ib. per sq. in. This shows that the 
 weld was stronger than the original metal. 
 
 The final conclusions drawn by Mr. Hughes from his tests, 
 are that, in general, the ultimate tensile strength of a properly 
 made butt- or spot-weld, is about 93 per cent of that of the 
 parent metal, and the ultimate shearing strength of a properly 
 made butt- or spot-weld is also about 93 per cent. 
 
 ELEMENTARY ELECTRICAL INFORMATION 
 
 What is a Volt? This is a term used to represent the pres- 
 sure of electrical energy. In steam we would say a boiler 
 maintains a pressure of 100 pounds. This term relates to pres- 
 sure only regardless of quantity, just as the steam pressure 
 of a boiler has nothing to do with its capacity. 
 
 What is an Ampere? This term is used to represent the 
 quantity of current. In the case of steam or water we speak 
 of carrying capacity of a pipe in cubic feet, while in electricity 
 the carrying capacity of a wire is given in amperes. 
 
 What is a Watt? This is the electrical unit of power and 
 equals volts X amperes. One mechanical horsepower is the 
 equivalent of 746 watts. 
 
 What is a Kilowatt or kw.? 1000 watts, kilo merely in- 
 dicating 1000. It is the most commonly used electrical unit 
 of power and one kilowatt of electrical energy is equivalent 
 to one and one-third mechanical horsepower. 
 
 What is a Kilowatt Hour or kw.-hr.? This is the electrical 
 equivalent of mechanical work, which would be stated in the 
 latter in terms of horsepower hour. It means the consumption 
 of 1000 watts of electrical energy steadily for one hour or any 
 equivalent thereof (such as 5000 watts for 12 minutes) and 
 
MAKING PROPER RATES FOR ELECTRIC WELDING 399 
 
 is the unit employed by all power companies in selling electric 
 power, their charges being based on a certain rate per kw.-hr. 
 consumed. 
 
 What is kva.? This means Kilo volt amperes or volts X 
 amperes-f-1000. This term is used only in alternating current 
 practice and is used to represent the apparent load on a 
 generator. In any inductive apparatus, such as a motor or 
 welder, a counter current is set up within the apparatus itself, 
 which is opposite in direction to and always opposes the main 
 current entering the apparatus. This makes it necessary for 
 the generator to produce not only amperes enough to operate 
 the motor or welder but also enough in addition to overcome 
 this opposing current in either of the latter, although the actual 
 mechanical power required to run the generator is only that 
 to supply watts or electrical energy ( volts X amperes) actually 
 consumed in the motor or welder. Hence, the kw. demand 
 of a welder represents the actual useful power consumed, for 
 which you pay, while the kva. emand represents the 
 vo Its X total number of amperes impressed on the welder-f-1000, 
 to also overcome the induced current set up within, but it is 
 the kva. demand that governs the size of wire to be used in 
 connecting up the welder. Kw. divided by kva. of any 
 machine, represents the power factor of that machine, which 
 is usually expressed in per cent. 
 
INDEX 
 
 Adapters for using carbons in metal- 
 lic electrode holder, *67 
 Adjustable table for spot welding 
 
 machines, *288, *292 
 Adjustment of die points for spot- 
 welding, *284, *297 
 All- welded mill building details, *166 
 Alternating-current apparatus, *42, 
 *43, *44 
 
 arc welding, 85 
 
 Aluminum butt-weld, *249, 252 
 
 welded to copper by percussion, 
 
 *274 
 
 American Institute of Electrical En- 
 gineers, paper read be- 
 fore, by H. M. Hobart, 
 167 
 
 Mining and Metallurgical 
 
 Engineers, paper read 
 before the, 223 
 American Machinist, 47, 66, 134, 324, 
 
 339 
 
 American Boiling Mills Co., elec- 
 trodes made by, 13 
 
 Steel and Wire Co., electrodes 
 
 made by, 13 
 
 gage numbers of, 
 
 140 
 
 Welding Society, 214 
 
 Ammeter charts of operation of Mor- 
 ton automatic metallic-electrode 
 welding machine, *224 
 
 Amount of metal deposited per hour 
 
 in arc welding, 89 
 Ampere, what is a, 398 
 Andrews, H. H., 212 
 
 W. S., 23 
 
 Angle and plate construction, *94 
 
 for holding carbon electrode, 69, 
 
 *70 
 
 of electrode in machine welding, 
 
 229 
 
 scarf for arc welding, 60 
 
 Annealing butt welds, 245, *246 
 
 welded tools, 356 
 
 Apparatus used in Bureau of Stand- 
 ards arc welding work, *174 
 
 Appearance of tension specimen af- 
 ter test, *183 
 
 Application of carbon arc welding, 
 77 
 
 ' ' Application of Electric Welding 
 to Ship Construction, " paper by 
 Jasper Cox on, 168 
 
 Arc and fusion characteristics, 52 
 
 , carbon, characteristics of, *70 
 
 control, 51 
 exercise, *52 
 
 on Morton machine, 225 
 
 formation, 50 
 
 -fused metal, formation of blocks 
 
 of, *175, 176 
 
 , macrostructure of, 184, *185, 
 
 *186, *187 
 
 , tests of, by Bureau of Stand- 
 ards, 189 
 , , by Wirt-Jones, 189 
 
 steel, change in nitrogen of, upon 
 
 heating, 209 
 
 , metallography of, 191 
 
 , microstructure of, 192, *193, 
 
 *194, *196, *198, *199, 
 
 *200, *202, *204, *206, 
 
 *207, *208 
 , physical properties of, 171 
 
 401 
 
402 
 
 INDEX 
 
 Arc steel, summary of results of the 
 study of the metallography 
 of, 212 
 
 - length for carbon-electrode work, 
 71 
 
 for various currents when 
 
 using carbon-electrodes, 71 
 
 in metallic-electrode welding, 
 
 82 
 
 maintenance, 50 
 
 manipulation, 49 
 
 in carbon-electrode welding, 
 
 69 
 
 , polarity of, in welding, 53 
 , short and long, deposits, *55 
 , welding, *54 
 
 stability, 54 
 
 weld inspections, 63, 96, 103 
 
 welding, automatic, 214, *217, 
 
 *218, *230, *236 
 
 circuits as first used, *3 
 
 equipment, 9 
 
 - high-speed tool tips, 162, *164 
 
 jobs, examples of, 127, *130, 
 
 *133, *137, *138, *139, 
 *140, *141, *142, *146, 
 *147, *148, *149, *153, 
 *154, *155, *156, *157, 
 *158, 159, 160, 161, 163, 
 164, 166 
 
 machine, a semi-automatic, 
 
 223, *230 
 Arc Welding Machine Co., The, 40 
 
 Co. 's constan t-current 
 
 closed circuit system, 
 40 
 electrode holder, *16, 
 
 *17 
 procedure, 81 
 
 - set, the G. E., *28 
 , speed of, 167 
 
 , , by machine, 220, 221, 
 
 222, 233, 238 
 
 terms and symbols, 109 
 
 Arcwell Corporation, 43 
 
 outfit for a-c current, *43 
 Armature shaft built up, *153 
 
 Arsem furnace, 208 
 
 Automatic arc welding, 214, *217, 
 
 *218, *230, *236 
 
 Automatic Arc Welding Co., 223 
 Automatic arc-welding head, 215, 
 
 *217, *218 
 machine, work done by, 
 
 219 
 
 butt-welding machines, *244, 
 
 *245 
 
 chain making machine, *269 
 
 - hog-ring mash welding machine, 
 
 *305, *306 
 
 Automatic Machine Co., 268 
 Automatic Pulley spot-welding ma- 
 chine, *301 
 
 spot-welder for channels, *300 
 Automobile body spot-welding ma- 
 chine with suspended head, 
 *294 
 
 muffler tubes, seam welded, *372 
 
 rim butt-welding work, 252, *255, 
 
 *259 
 
 Axle housings repaired, *156 
 , worn, built up, *160 
 
 B 
 
 Back-step arc welding, 84 
 Balancer-type arc welding set, *28 
 Band saw welding, *251, 252 
 Bench type of spot-welding machine, 
 
 *248 
 
 Bernardos process, the, 1, 2, *3 
 Blow-pipe, electric, the, 1, *2 
 Body, automobile, spot-welding ma- 
 chine with suspended head, *294 
 Boiler tube arc welding, *142, 143 
 
 rolling machine, simplest 
 
 form of, *331 
 
 welding with the arc, *89 
 
 tubes, leaks in, 333 
 
 , ready for flash-welding, *.",L ) 9 
 
 Bolt holes, filling, 160 
 Booth, the welding, 48 
 Bouchayer's spot-welding apparatus, 
 
 *6, 7 
 Box, spot-welding a sheet steel, *283 
 
INDEX 
 
 403 
 
 Brass, butt-welding, 267 
 
 seam welding, 366 
 
 Bronze, welding with carbon arc, 
 
 76 
 
 Bucket voiding jig, *375 
 Building up a surface with carbon 
 arc, *72 
 
 round work, speed of, 223 
 
 worn shafts and axles, *153, 
 
 *160 
 Built-up carbon arc weld, section 
 
 through a, *73, *75 
 Bureau of Standards, study of arc- 
 fused steel at, 171 
 
 , tests on arc-fused steel at, 
 
 191 
 
 Burning, lead, outfit, *45, 46 
 Butt weld (arc), definition of, 110 
 
 , boiler tube ends prepared for, 
 
 *327 
 
 -welding attachment for spot- 
 
 welding machine, *286 
 
 boiler tubes, 336 
 
 device, first practical, *4 
 
 end rings, *266 
 
 jobs, examples of, 247, *249, 
 
 *250, *251, *255, *265, *266, 
 *267, *268 
 
 machine, principal parts of, *240 
 work clamps, *242, *243, 
 
 *257 
 
 machines, *345, *347, *348, *351 
 and work, 239, *240, *241, 
 
 *244, *245, *246, *251, 
 *254, *256, *257, *259, 
 *261, *262, *263, *264, 
 *267, *268 
 
 patents, 4 
 
 pipe, cost and consumption of, 
 258 
 
 rod up to % in. dia., cost and 
 
 current consumption of, 248 
 
 stock up to 2 in. dia., cost and 
 
 current consumption of, 263 
 
 -welds, metallic electrode, data 
 
 on, 32 
 , strength of resistance, 394 
 
 Cable, size of, for arc welding work, 
 
 18 
 
 Cain, J. R., 177, 178 
 Cam-operated butt-welding machine, 
 
 *244, *245 
 
 Can seams, line-welding, *308 
 welding jig, *374 
 Car axle enlarged, *160 
 
 equipment, electric, maintenance 
 
 of, 150 
 Carbon arc, characteristics of, *70 
 
 , cuts, examples of, *77 
 
 spot-welding, *5, *7 
 
 welding, *15 
 
 , application of, 77 
 
 , filler used for, 68 
 
 electrode apparatus, original, *3 
 arc seam-welding machine, 
 
 *236, 237 
 
 welding and cutting, 66 
 
 current used with, 66, 68, 71, 
 
 74, 78, 80 
 
 cutting speeds, 31 
 
 process, 10 
 
 , size of, 10, 68 
 
 Cases, motor, reclaimed, *154 
 Cast iron, rate of cutting, with car- 
 bon arc, 79 
 
 , welds, strength of, 131 
 
 Caulking weld (arc), definition of, 
 
 116 
 
 Chain machine, automatic, *269 
 Challenge Machinery Co., 288 
 Change in nitrogen content upon 
 
 heating arc-fused steel, 209 
 Channel iron spot-welding machine, 
 
 automatic, *300 
 
 Characteristic appearance of tension 
 specimen after test, *183 
 
 " needles" or "plates" in arc 
 
 fused steel, 195, *196, *198, 
 *199, *200, *202, *204, *206, 
 *207, *208 
 
 structure of electrolytic iron, 
 
 *199 
 
404 
 
 INDEX 
 
 Characteristics of arc and fusion, 52 
 
 carbon arc, *70 
 
 the metallic arc weld, factors 
 
 that determine the, 97 
 
 , thermal, of arc-fused iron, 210, 
 *211 
 
 Chemical analyses of arc deposited 
 specimens, 105 
 
 Chemical and Metallurgical Engi- 
 neering, 171, 396 
 
 Chemical composition of metallic 
 electrodes, effects of the, 104 
 
 Chicago, Rock Island and Pacific 
 railroad arc welding work, 84 
 
 Chubb, L. W., 269 
 
 Circuit, schematic welding, *10 
 
 Circular arc welding, automatic, 
 *217 
 
 Clamp for butt-welding pipe, *257 
 
 heavy, flat, butt-welding 
 
 work, *243 
 
 tool welding, *346 
 
 , foot-operated, for butt-welding 
 work, *242 
 
 , hand-operated, for butt -welding 
 work, *242 
 
 toggle lever, for butt-welding 
 
 round stock, *242 
 
 Clamping distance, effect of, on 
 time and energy demand, 385 
 
 jaws for boiler tube work, *337 
 Clamps for work in butt-welding ma- 
 chines, *242, *243, *257 
 
 Classes of electric welding, 1 
 Close-up of tool-welding machine 
 with work in place, *352 
 
 view of left-hand tool-welding 
 
 clamp, *346 
 
 Coating for metal electrodes, 176 
 
 Coils, butt-welding pipe, *256 
 
 Collins, E. F., 263 
 
 Combination arc welding symbols, 
 118, *119, *120, *121, *122, 
 *123, *124, *125, *126 
 
 spot- and line-welding machines, 
 
 307, *308, *309, *310 
 
 e wpld (arc), definition of, 
 
 Composition of electrodes before 
 and after fusion, 177, 
 178 
 
 used in Morton machine, 
 
 227, 228, 229 
 
 metallic electrodes, 12 
 
 Welding Committee elec- 
 trodes, 107 
 
 Comstock, G. F., reference to, 197 
 Concave weld (arc), definition of, 
 
 118 
 
 Condenser, arc welded, *138 
 Connections for G. E. constant-en- 
 ergy, constant-arc set, *30 
 Constant-current closed-circuit weld- 
 ing outfit, 40 
 
 Contraction of deposited metal in 
 arc welding, 58, *59 
 
 and expansion of parent metal in 
 
 arc welding, 57, *59 
 Control of arc direction exercise, *52 
 travel, 51 
 
 panel for balancer set, *29, *30 
 Controlling the arc on Morton ma- 
 chine, 225 
 
 Convenient setting of machine for 
 spot-welding sheet metal work, 
 *295 
 
 Copper butt-welding, 263 
 
 -welds, *249, 252 
 
 jaws for boiler tube work, *337 
 holding large heads and 
 
 small shanks, *350 
 
 welding various sizes of 
 
 tools, *349 
 
 welded to aluminum by percus- 
 
 sion, *274 
 
 , welding, with carbon arc, 76 
 Correct welding posture, *49 
 Cost of arc welding, 90 
 
 in railroad work, 144 
 
 butt- and mash-welding, vari- 
 ous sizes, 362 
 
 butt-welding work, 248, 258, 
 
 263 
 
 machine and hand arc-welding 
 
 compared, 221, 222 
 metallic electrode welding, 32 
 
INDEX 
 
 405 
 
 Cost of percussive welds, 272 
 
 pod welds, 147 
 
 repairs in welding flues, 336 
 
 seam welding, 378 
 
 spot-welds, 321 
 
 - : welding boiler tubes, 335 
 Cox, H. Jasper, 168 
 Crane wheels, repaired, *221 
 Crank forging weld, *250, 252 
 Crankshaft, arc welding a 6-ton, 
 
 *161, 162, *163 
 Cross-current spot-welding machine, 
 
 *302, *303 
 Cross-overs, repaired manganese 
 
 steel, *147 
 
 Current action in a Taylor spot- 
 welding machine, *304 
 
 and electrode diameter, relation 
 
 of, *13, 14 
 
 consumption for butt- and mash- 
 
 welding various sizes, 
 
 362 
 butt-welding, 248, 258, 
 
 263 
 
 welding 6-in. seam, 378 
 
 in carbon arc cutting, 80 
 
 density of electrode, 61 
 
 for , given cases of arc welding, 
 
 169 
 
 required for metallic electrode 
 
 welding, 32 
 
 percussive welds, *273 
 
 ship plate spot-welding, 
 
 311, 315, 317, 318, 319 
 spot-welds, 321 
 
 used for automatic arc welding, 
 
 220, 221, 222, 223, 228, 
 232, 238, 
 
 cutting with the carbon 
 
 arc, 78, 80 
 
 various sizes of carbon- 
 electrodes, 68 
 
 in Bureau of Standards tests, 
 
 176 
 
 butt-welding, 240, 243, 
 
 247, 248, 255, 258, 259, 
 260, 261, 262, 263 
 
 Current used for carbon electrode 
 
 process, 11 
 metallic electrode process, 
 
 11 
 
 values for plates of different 
 
 thickness, 14 
 
 variation, effect of, on strength 
 
 of arc weld, 102 
 Currie, H. A., 143 
 Curves showing thermal characteris- 
 tics of arc-fused iron, *211 
 Cutting speeds with carbon elec- 
 trodes, 31 
 
 with the carbon arc, 77 
 , current used in, 78, 
 
 80 
 
 Cutting-off machine for boiler tubes, 
 *325 
 
 Cuts made with the carbon arc, ex- 
 amples of, *77 
 
 Cylinder, locomotive, welding with 
 the arc, 144 
 
 Cylinders, Liberty, butt-welding 
 valve elbows on, *268 
 
 Dangerous light rays, 23 
 
 Data for metallic electrode butt and 
 
 lap welds, 32 
 De Beriardo spot-welding apparatus, 
 
 the, *5, 7 
 Decimal equivalents of an inch for 
 
 millimeters, B. & S. and Birming- 
 ham wire gages, 323 
 Demand, maximum, in resistance 
 
 welding, 387 
 de Meritens, 1 
 Deposit obtained with short and 
 
 long arc, *55 
 
 per hour, arc welding, 89, 146 
 , the&ry of electrode, 223 
 Deposited metal, contraction of, in 
 
 arc welding, 58, *59 
 Deposits of short and long arcs, 
 
 *102, *103 
 Design of arc welded joints, 90 
 
406 
 
 INDEX 
 
 Details of percussive welding ma- 
 chine and wiring diagram, 
 *271 
 
 rotor welding machine, *265 
 
 seam welding roller head, 
 
 *368 
 
 standard spot-welding ma- 
 chines, 278, *279 
 
 Diagram of control of feed motor 
 for automatic arc-welding 
 machine, *219 
 
 flange seam welding opera- 
 tion, *380 
 
 Die-points for heavy spot -welding, 
 314 
 
 spot-welding machines, 288, 
 
 *289, *290, *291, *297, 
 *304 
 
 Different makes of arc welding sets, 
 28 
 
 Direction of arc travel, 51 
 
 Double bevel, definition of, as ap- 
 plied to edge finish, 114 
 
 ' ' V, ' ' definition of, as applied to 
 edge finish, 113 
 
 Drill blanks just welded, *349 
 
 Drills, Stellite tipped, *348 
 
 Driving wheel welding, *141, 143 
 
 Duplex spot-welding machine with 
 6-ft. throat depth, *316 
 
 Dynamotor, plastic arc, welding set, 
 35, *36 
 
 E 
 
 Edge finish, 112, 113, 114 
 
 Edges, flanged, welded with carbon 
 
 arc, *75, 76 
 
 Effect of clamping distance on 
 time and energy demand, 
 385 
 
 pronounced heating upon the 
 
 structure of arc-fused iron, 
 *206, *207, *208 
 Effects of the chemical composition 
 
 of metallic arc electrodes, 104 
 Electric Arc Cutting and Welding 
 Co., 44 
 
 Electric arc, heat of the, 9 
 
 and oil heating of boiler tubes 
 
 compared, 335 
 
 " blow-pipe, " the, *2 
 
 car equipment maintenance, 150 
 Electric Railway Journal, 150 
 Electric seam welding, resistance, 
 
 365 
 
 welded ship, 134 
 
 welding, classes of, 1 
 Electric Welding Co. of America, 
 
 building for the, 164 
 Electric welding of high-speed steel 
 
 and Stellite in tool manufacture, 
 
 343 
 
 Electrical inspection of welds, 98 
 Electrical World, 382 
 Electrically welded mill building, 
 
 164 
 
 Electrode, angle of, in machine weld- 
 ing, 229 
 
 , carbon, original apparatus, 2, *3 
 , , size of, 68 
 
 current density, 61 
 
 deposit, theory of, 223 
 
 diameter versus arc current, *13 
 
 diameters for welding steel plate, 
 
 101 
 
 holder, a simple form of, *16 
 
 , special form, *16, *17 
 
 material, analysis of, used in 
 
 Morton machine, 227, 228, 229 
 , metallic, original apparatus, 2, *3 
 , , speed of welding with, 32 
 , size of for arc welding, British 
 
 practise, 169 
 
 wire, best, to use in arc-welding 
 
 machine, 231 
 
 Electrodes before and after fusion, 
 composition of, 177, 178 
 
 , composition of Welding Commit- 
 tee, 107 
 
 , fusion of, 50 
 
 , graphite see Carbon 
 
 , hardness of, 180, 181 
 
 , metallic, composition of, 12 
 
 , , made by various firms, 13 
 
 , selection of, 12 
 
INDEX 
 
 407 
 
 Electrodes, size of, 13, 14 
 , tensile properties of, 179, 180, 
 181 
 
 used for carbon arc welding, 66, 
 
 *67, 68 
 Electro-percussive welding, 269 
 
 machine, *270, *271, 272 
 
 Elementary electrical information, 
 
 398 
 
 End, strip, welding jig, *376 
 Energy consumption of resistance 
 
 welding for commercial grades of 
 
 sheet iron, 384 
 Escholz, O. H., 47, 66, 96 
 Etching fluid, 55 
 
 solution used by Bureau of 
 
 Standards for steel, 185, 186, 
 
 187, 193, 194, 196, 198, 199, 
 
 200, 202, 204, 206, 207, 208 
 
 Equipment, a welder 's, 64 
 
 Examples of arc welding jobs, 127 
 
 *130, *133, *137, 
 
 *138, *139, *140, 
 
 *141, *142, *146, 
 
 *147, *148, *149, 
 
 *153, *154, *155, 
 
 *156, *157, *158, 
 
 *159, *160, *161, 
 
 *163, *164, *166 
 
 work, *87, *88, *89 
 
 butt-welding jobs, 247, *249 
 
 *250, *251, *255, *265, 
 *266, *267, *268 
 
 seam welding, *371, *372, 
 
 "374, *375, *380 
 welded ship parts, *137 
 Exercises for the beginner in arc 
 
 welding, 58, *59 
 expansion and contraction of parent 
 
 metal in arc welding, 57, *59 
 Eye protection in iron welding op- 
 erations, 23 
 
 Face masks and shields, *15, *18, 
 
 *19 
 Factors that determine degree of 
 
 fusion, 64 
 
 Federal butt- welding machines, 261, 
 
 *262, *263, *268 
 Federal Machine and Welder Co., 
 
 261, 297 
 Federal spot-welding machines, *296, 
 
 297, *299, *300, *301 
 
 water-cooled die points, *297, 
 
 *298 
 Feed control diagram of arc welding 
 
 machine, *219 
 Ferride Electric Welding Wire Co., 
 
 electrodes made by, 13 
 Fillet weld (arc), definition of, 111 
 Filler material for carbon arc weld- 
 ing, 68 
 
 rods, fused ends of, used in car- 
 
 bon arc welding, *74 
 Filling in bolt holes, 160 
 
 sequence in arc welding, *83, 
 
 *84, *85 
 
 Firebox sheet work, *95 
 Flange, repair of electric car wheel, 
 
 *157, *158 
 
 seam welding, 374, *377, *380 
 , diagram of operation of, 
 
 *380 
 
 Flanged edges welded with carbon 
 arc, *75, 76 
 
 seam welding with carbon arc, 
 
 *75, 76 
 
 Flash-welding boiler tubes, 336, 338 
 Flat position defined as applied to 
 
 ship work, *114, 115 
 Flue ends just beginning to heat, 
 
 *340 
 
 almost hot enough for weld- 
 ing, *341 
 
 prepared for flash-weld, *329 
 
 , rolling out upset metal on, 
 
 *341 
 
 parts in machine ready for weld- 
 
 ing, *340 
 
 welding (arc), *142, 143 
 machine, close-up of, showing 
 
 inside mandrel, *339 
 
 , pressure required for, 337 
 with the arc, *89 
 
 work, machine for, 337 
 
408 
 
 INDEX 
 
 Flues, cutting off boiler, *325 
 , leaks in welded, 333 
 Flush weld (arc), definition of, 118 
 Flux for flue welding, using a, 330 
 
 used for seam welding, 366 
 Forge, the "water-pail," 1, 3 
 Form of points for spot-welding, 
 
 *289, *290, *291, *297, *298, *304 
 Formation of arc, 50 
 Fractures of test specimen of arc 
 
 deposited plates, *105 
 Frame welding, locomotive, *89, 
 
 *139, *140 
 
 ' l Free distance, ' ' meaning of, 63 
 reduction caused by contrac- 
 tion, *59 
 1 1 Freezing ' ' of electrodes, meaning 
 
 of, 50, 64 
 Fused ends of filler rods used in 
 
 carbon arc welding, *74 
 Fusion and arc characteristics, 52 
 , factors that determine degree of, 
 64 
 
 of electrodes, 50 
 
 parent metal and four layers 
 
 of carbon arc deposit, *75 
 , poor and good, from arc, *60 
 
 Galvanized iron, welding, 277, *286 
 Gear-case repair, *155 
 
 cases with patches welded on, 
 
 *159 
 
 , split, made solid, *160 
 General Electric arc-welding gen- 
 erator direct con- 
 nected to motor, 
 *152 
 - set, *28 
 
 butt-welding machine for 
 
 rotor work, *264, *265, 
 *266, *267 
 
 Co., 17, 28, 46, 151, 154, 214, 
 237, 307, 308, 319 
 
 portable arc-welding outfit, 
 
 *151 
 
 General Electric Review, 21, 23, 263, 
 311 
 
 General Electric space-block spot- 
 welding machine, *307 
 
 features of microstructure of arc- 
 
 fused steel, 142 
 "George Washington," repair of 
 
 the, *130 
 
 German ships, extent of damage to 
 seized, 128 
 
 , repaired, 127 
 Gibb Instrument Co., 42 
 
 Glass, qualities of various kinds of, 
 25 
 
 Good and bad arc welds, *100 
 
 Graphite electrodes see Carbon 
 
 Groesbeck, Edward, 171 
 
 Grooved tool parts to facilitate weld- 
 ing, *364 
 
 Guards, spot-welding 12 gage iron, 
 *287 
 
 H 
 
 Haas, Lucien, 290 
 
 Ham, J. M., 21 
 
 Hand shield, using a, *15 
 
 shields for arc welders, *15, *19 
 Hardness of electrodes, 180, 181 
 Harmatta spot-welding process, prin- 
 ciple of the, *7 
 
 Harness rings, welding, *245 
 Hartz type boiler tube rolling ma- 
 chine, *332 
 
 Heat conductivity and capacity in 
 arc welding, 57 
 
 of the electric arc, 9 
 
 treatment of arc welds, 103 
 Heating arc-fused steel changes 
 
 nitrogen content, 209 
 
 , effect of, on structure of arc- 
 fused iron, *206, *207, *208 
 
 Heavy-duty spot-welding machine, 
 *283, *292, *303, *312, *316, 
 *318 
 
 experimental spot-welding ma- 
 
 chine, *318, 319 
 Herbert Mfg. Co., 296 
 High carbon steel welds, strength of, 
 
 396 
 
INDEX 
 
 409 
 
 High-speed steel, welding, 343 
 
 to low-carbon steel, welding, 344 
 
 tool tips, arc-welding, 162, *164 
 Hobart, H. M., 167, 189, 223, 390 
 Hoe blades, welding, to shanks, 
 
 *284 
 Holder, electrode, simple form of 
 
 *16 
 , , special form of, *16, *17 
 
 for carbon-electrode, *67 
 
 metallic-electrode, *67 
 
 , the electrode, 48 
 
 Holding stock of unequal size for 
 
 butt-welding, *350 
 Holes, filling bolt, 160 
 , strength of spot-welded, 392, 
 
 *393 
 
 Horizontal position defined as ap- 
 plied to ship work, *114, 115 
 Housing, repaired 5-ton roll, 147, 
 
 *148 
 
 , welded rear axle, *222 
 Houston Ice Co., crankshaft repair 
 
 for, 162 
 
 How horn and welding points may 
 be set for spot welding, *284, 
 *297 
 
 the metal edges of a tank are 
 
 arc welded, 237 
 Hub, welded automobile, *221 
 Hughes, G. A., 397 
 
 Inclusions in arc-fused steel, " metal- 
 lic-globule," *194, 195 
 Insert tool welding, *355, *357 
 Inspection of arc welds, 63, 96, 103 
 
 Jacob, W., 263 
 
 Jaws and work arranged for a mash 
 weld, *361 
 
 for boiler tube work, *337 
 
 holding two sizes of stock, 
 
 *350 
 
 tool welding, *346, *349, *350, 
 *354, *355, *356, *357 
 
 Jessop, E. P., 13] 
 
 Jigs for holding seam welding work, 
 372, *373, *374, *375, *376, *380 
 Joints arc welded, design of, 90 
 , stresses in arc welded, 92, *93 
 Jordan, Louis, 171 
 
 Karcher, A. A., 288 
 
 Kent, William, report on butt-welds 
 by, 394 
 
 Kerosene, use of, in inspection, 63, 
 98 
 
 Kilowatt-hour, what is a, 398 
 
 , what is a, 398 
 
 Kind of machine to use for welding 
 flues, 337 
 
 King face masks, *15, *18 
 
 Optical Co., Julius, 18 
 
 Kleinschmidt spot-welding appara- 
 tus, the, *5, 7 
 
 Kva., what is, 399 
 
 La Grange-Hoho process, the, 1, 3 
 Lap weld (arc), definition of, 110 
 Lamp shades, mash-welding, *285 
 Lap seam welding machines, 368 
 -welds, metallic electrode, data 
 
 on, 32 
 
 Lathe tool, welded and finished, *354 
 Layers of filling material in carbon 
 
 arc welding, *73, *74, *75 
 Lead-burning outfit, G. E., *45, 46 
 , welding, with carbon electrode, 
 
 76 
 
 Leaks in welded boiler tubes, 333 
 Lloyd's Kegister, 135 
 Liberty motor cylinders, butt-weld- 
 ing valve elbows on, 268 
 Light manufacturing type of spot 
 
 welding machine, *281 
 - rays, dangerous, 23 
 Lincoln Electric Co., 21, 37, 81 
 welding set, the, 36, *37 
 Line-welding can seams, *308 
 Lining up large crankshaft for arc 
 welding, *163 
 
410 
 
 INDEX 
 
 Load factor in resistance welding, 
 386 
 
 tests of all-welded mill building, 
 
 165 
 
 ' ' Locked-in ' ' stresses, result of, 62 
 Locomotive arc welding work, 140 
 
 frame welding, *89, *139, *140 
 Long and short arc deposits, *55 
 welding arc, *54 
 
 Lorain machine for spot-welding 
 electric rail bonds, *320, 321 
 
 Lorain Steel Co., 321 
 
 Lunkenheimer laboratory tests of 
 spot welds, 391 
 
 M 
 
 MacBean, T. Leonard, 164 
 Machine for flange-seam welding, 
 
 . 377 
 , kind of, to use for flue welding, 
 
 337 
 
 Machines for resistance butt weld- 
 ing, 239, *240, *241, *244, *245, 
 *246, *251, *254, *256, *257, *259, 
 *261, *262, *263, *264, *267, *268 
 Macrostructure of arc-fused metal, 
 
 184, *185, *186, *187 
 Maintenance of arc, 50 
 
 electric car equipment, 150 
 
 Making a "mash" insert weld, *359 
 proper power rates, 382 
 Mandrels used in flue welding, 330, 
 
 331, 333, *334, *339 
 Manganese steel cross-overs, re- 
 paired, 147 
 Manipulation of arc, 49 
 
 the arc in metallic electrode 
 
 welding, 82 
 Martensite structure in arc-fused 
 
 steel, *204 
 Mash welding, 284, *285, 306, *319 
 
 machines, *358, *359, *360 
 
 Mask, using a, in arc welding, *15 
 Masks, King, for arc welding, *15, 
 
 18 
 
 Maximum demand in resistance 
 welding, 387 
 
 Mechanical properties of arc-fused 
 metal deposited at right 
 angles to length of 
 specimen, 184 
 
 twelve good arc welds, 173 
 
 twelve inferior arc welds, 
 
 173 
 
 Melting steel in nitrogen under 
 pressure, 212 
 
 Merica, P. D., 197 
 
 Merits of electric and oil heating of 
 boiler tubes, 335 
 
 Metallic arc welding, *15 
 
 electrode apparatus, original, 2, 
 
 *3 
 
 process, 10, 11 
 
 speed of welding with, 32 
 
 ' ' Metallic-globule ' ' inclusions in 
 arc-fused steel, *194, 195 
 
 Metallography of arc-fused steel, 
 191 
 
 Metals, non-ferrous, welding with 
 carbon arc, 76 
 
 Methods of welding boiler tubes, the 
 three, 328 
 
 , the three, of welding boiler tubes 
 compared, 336 
 
 Microphotographs of specimens of 
 arc deposited metal, *106 
 
 Microscopic evidence of unsound- 
 ness of arc-fused metal, 193 
 
 Microstructure of arc-fused steel, 
 192, *193, *194, *196, *198, *199, 
 *200, *202, *204, *207, *208 
 
 Mill building, electrically welded, 
 164 
 
 , welded parts of, *166 
 
 Miller, S. W., 197, 201 
 
 Morton, Harry D., 223 
 
 semi-automatic metallic-electrode 
 
 arc-welding machine, *230 
 Motor cases reclaimed, *154 
 Muffler tube welding jig, *373 
 
 tubes, seam welded, *372 
 
 N 
 
 " Needles " in arc-fused metal, 195, 
 *196, *198 
 
INDEX 
 
 411 
 
 New York Central railroad arc weld- 
 ing work, 143 
 
 Nitrates probably cause of plates in 
 fusion welds, 197 
 
 Nitride plates, persistence of, 208 
 
 , two types of, *199 
 
 Nitrogen content and current den- 
 sity, relation of, 178, 179 
 
 Non-ferrous metals, welding, with 
 carbon arc, 76 
 
 Oesterreicher, S. I., 382 
 Oil and electric heating of boiler 
 tubes compared, 335 
 
 stove burner tubes before and 
 
 after seam welding, *371 
 Oscillograph chart of percussive 
 welds on 18 gage aluminum wire, 
 273 
 
 Orton, J. S., 104 
 Outfit, selecting a welding, 21 
 Outfits, welding, types of, 21 
 Overhead position defined as applied 
 to ship work, *114, 115 
 
 seam welding, 62 
 
 Overlap and penetration studies, 
 
 *56, 57 
 "Overlap," meaning of, 63 
 
 Page Woven Wire Co., electrodes 
 made by, 13 
 
 Panel control for balancer set, *29, 
 *30 
 
 Parent metal in arc welding, ex- 
 pansion and contraction of, 57, 
 *59 
 
 ' ' Parent metal, ' ' meaning of, 63 
 
 Payne, O. A., 168 
 
 Pearlite islands in arc-fused steel, 
 *198 
 
 Pedestal jaw, built-up, *139 
 
 Penetration and overlap studies, *54, 
 57 
 
 , current required for proper, 57 
 
 " Penetration, " meaning of, 63 
 
 Pennington, H. E., 84 
 Percussive welding, 269 
 
 , the possibilities of, 274 
 
 Physical characteristics of plates 
 tested, 104 
 
 properties of arc-fused steel, 171 
 Piloted cup, machine welded, *227, 
 
 *228, *229 
 Pinion blank weld, *250, 252 
 
 pod, finished welded, *148 
 Pipe, cost and current consumption 
 
 for butt-welding, 258 
 
 heading, *95 
 
 , spot welding galvanized iron, 
 *286 
 
 welding, 255 
 
 Plastic arc dynamotor set, 35, *36 
 
 welding sets, *33, *36 
 
 Plate and angle construction, *94 
 
 thickness versus arc current, *13 
 "Plates" in arc-fused metal, 195, 
 
 *196, *198 
 Plates, nitride, two types of, *199 
 
 probably due to nitrates, 197 
 
 remain long after annealing of 
 
 arc-fused metal, 208 
 Plug weld (arc), definition of, 111 
 Plugged plates, strength of, 392, 
 
 *393 
 " Pocohontas, " repair of the, 132, 
 
 *133 
 
 Pods, building up roll, *147, *148 
 Points for spot-welding work, 288, 
 
 *289, *290, *291, *297, *298, *304 
 Polarity for carbon arc work, 70 
 
 in arc welding, 53 
 
 carbon electrode process, 11 
 
 Portable arc welding set, *37, *38, 
 
 *39, *42, *43, *44> *45 
 butt-welding machines, 247, *257 
 
 spot-welding machines, *292, 
 
 *293 
 
 machine with 27-in. throat 
 
 depth, *312 
 Position, correct, for using carbon 
 
 arc and filler rod, *69 
 Positions of the universal spot-weld- 
 ing points, a few, *297 
 
412 
 
 INDEX 
 
 Posture and equipment of arc 
 
 welder, *49 
 Potts Co., John, electrodes made by, 
 
 13 
 
 Power factor in resistance welding, 
 383 
 
 rates, making proper, 382 
 
 required for percussive welds, 
 
 272, *273 
 
 Pressure required for flue welding, 
 337 
 
 heavy spot welding, 312, 
 
 313, 317 
 Principal parts of a butt-welding 
 
 machine, *240 
 
 Projection allowed in welding boiler 
 tubes, 330, *337, *340 
 
 method of welding, *291 
 Properties, mechanical, of twelve 
 
 good arc welds, 173 
 , , inferior arc welds, 173 
 
 of arc-fused metal deposited at 
 
 right angles to length of speci- 
 men, 184 
 
 , tensile, of electrodes, 179, 180 
 Protecting the eyes in arc welding, 
 
 23 
 
 Pulley spot-welding machine, auto- 
 matic, *301 
 
 Pulleys repaired by arc welding, 
 *149, 150 
 
 Qualities of various kinds of glass, 
 
 25 
 Quasi arc welding, 86 
 
 , speed of, 168 
 Quasi Are Weltrode Co., 86 
 weltrodes, how to use, 86 
 
 Rail bonds, spot-welding, *320, 321 
 ends, built up cupped, 146 
 Railroad arc welding work, 145 
 Railway Age, 143 
 Rate of arc weldipg, 146 
 
 Rates, making proper power, 382 
 
 Rays, the infra-red, 23 
 
 , ultra-violet, 23 
 
 , visible light, 23 
 
 Reamer, steps in making a large, 
 *353 
 
 * ' Recession, ' ' meaning of, 63 
 
 ' ' Re-entrant angle, ' ' meaning of, 63 
 
 Reinforced weld (arc), definition of, 
 117 
 
 Relation of arc current and electrode 
 diameter, *13, 14 
 
 microstructure to the path of 
 
 rupture in arc fused metal, 
 201 
 
 nitrogen content and current 
 
 density, 178, 179 
 
 Removing broken taps, 150 
 
 Repairing crane wheels, 221 
 
 Resistance welding, 4 
 
 , energy consumption of, 384 
 
 machine, 239 
 
 Rims, automobile, butt-welding, 252, 
 *255, *259 
 
 Ring welded to core with arc weld- 
 ing machine, *232 
 
 Rivets in a ship, number of, 136 
 
 Rods, strength of mash- welded, *394 
 
 Roebling's Sons Co., John A., elec- 
 trodes made by, 13 
 
 Roll housing, repaired, *148 
 
 Rolling boiler tubes, *331, *332, 
 *334, *341 
 
 out upset metal on flue ends, 
 *341 
 
 Rotatable head two-spot welding 
 machine, 298, *299 
 
 Rotor ring butt-welding work, 263 
 
 Rovvdon, Henry S., 171 
 
 Ruder, W. S., reference to, 199, 205, 
 208, 209 
 
 Rules, general, for arc welders, 146 
 
 S 
 
 Saw, butt-welding a band, *251, 252 
 Scarf angle for arc welding, 60 
 "Scarf, " meaning of, 63 
 
INDEX 
 
 413 
 
 Scarf-weld, boiler tube ends pre- 
 pared for, *326 
 
 welding boiler tubes, 336 
 
 Scarfing machine, a, *326 
 Scarfs, typical arc weld, *99 
 Schematic welding circuit, *10 
 Screens for arc welding, *19 
 Seam, automatic arc welded tank, 
 
 *222 
 
 , flange, welding, 374, *377, *380 
 , flanged, welding with carbon arc, 
 *75, 76 
 
 welding by the resistance process, 
 
 365 
 
 , current consumption for, 378 
 
 , details of roller head for, 
 
 *368 
 
 machines, *367, *369, *370, 
 
 *373, *374, *375, *376, 
 *377 
 
 , material to use for, 365, 366 
 
 , speed of, with automatic arc 
 
 machine, 222 
 Sectional view of carbon arc built-up 
 
 weld, *73, *75 
 
 Selecting a welding outfit, 21 
 Self-contained portable welding set, 
 
 Lincoln, *37 
 Semi-automatic arc-welding machine, 
 
 223, *230 
 
 Shaft, building up a, with an auto- 
 matic arc welding machine, *218 
 , built up motor, *220 
 Shafts, worn armature, built up, 
 
 *153 
 
 Shearing strength of butt- and spot- 
 welds, 397 
 Sheet iron and steel, thickness and 
 
 weight of, 322 
 
 , energy consumption in weld- 
 ing, 384 
 
 metal arc-welding machine, *236, 
 
 237 
 
 work, convenient set-up for 
 
 spot-welding, *295 
 
 steel box, spot-welding a, *283 
 Shell, cup for, welded by machine, 
 
 *227, *228, *229 
 
 Shells, motor, repaired, *154, *156 
 Shields, hand, for arc welders, *15, 
 
 *19 
 
 Ship parts, welded, examples of, 
 *137 
 
 plates automatically arc-welded, 
 
 *234, *235 
 
 work, spot-welding machines for, 
 
 311, *312, *316, *318, *319 
 Ships, German, names of, 127 
 Shops of the Santa Fe E. K., 339 
 Short and long arc deposits, *55 
 
 welding arc, *54 
 
 Single bevel, definition of, as ap- 
 plied to edge finish, 114 
 
 "V," definition of, as applied 
 
 to edge finish, 112 
 Size of cable for arc welding work, 
 18 
 
 carbon-electrode, 68 
 
 electrode for metallic arc 
 welding of steel plate, 101 
 
 electrodes, 13, 14 
 
 Sizes of die-points for spot-welding, 
 *290 
 
 electrodes used in automatic 
 
 arc-welding machines, 220, 
 221, 222, 223, 232, 238 
 
 wire to use for connecting up 
 
 different sizes of butt-weld- 
 ing machines, 363 
 Slavianoff process, the, 1, 2 
 Sliding horn spot-welding machine, 
 
 *291 
 
 Slip-bands, 188, 202 
 Smith, J. O., 134 
 Society of Naval Architects, 168 
 Solutions, etching, for steel, 185, 
 186, 187, 193, 194, 196, 198, 199, 
 200, 202, 204, 206, 208 
 Space-block spot-welding machine, 
 
 *307 
 
 Stability of arc, 54 
 Special set up of arc welding ma- 
 chine for building up a 
 shaft, *218 
 
 machine for circular arc 
 
 welding, *217 
 
414 
 
 INDEX 
 
 Speed of arc travel, 51 
 
 welding, 90, 167 
 
 automatic arc welding ma- 
 chine, 220, 221, 222, 233, 
 238 
 
 building up shafts or wheels 
 
 with automatic arc ma- 
 chine, 223 
 
 cutting with the carbon arc, 
 
 78, 79, 80 
 
 < carbon electrode, 31 
 
 deposit per hour in arc weld- 
 ing, 89 
 
 percussive welding, 272, *273 
 
 Quasi- Arc welding, 168 
 
 seam welding with auto- 
 matic arc machine, 222 
 
 spot-welding, 321 
 
 welding boiler tubes, 333, 335 
 
 with metallic electrode, 32 
 
 Split-gear made solid, *160 
 Spokane & Inland Empire K. R., re- 
 claimed wheels on, 157 
 Spot- and line-welding machines, 
 combination, *308, *309, *310 
 
 welded holes, strength of, 392, 
 
 *393 
 
 material that can be, 277 
 Spot-welding apparatus, first forms 
 
 of, *5, *6, *7, *8 
 
 machines and work, 276, *278, 
 
 *279, *281, *282, *283, 
 *284, *285, *286, *287, 
 *288, *291, *292, *293, 
 *294, *295, *296, *299, 
 *300, *301, *302, *303, 
 *305, *307, *308, *309, 
 *310, *312, *316, *318, 
 *319, *320 
 
 , details of standard, 278 
 
 for ship work, 311, *312, 
 
 *316, *318, *319 
 
 patents, *5, *6, 
 
 *8 
 
 power and cost data, 321 
 
 tests on hoop iron, *390, 391 
 Spraragen, William, 167 
 
 Square patch arc welding method, 
 
 *85 
 
 Stalls, individual, for arc welders, 
 *20 
 
 Steel etching solutions, 185, 186, 
 187, 193, 194, 196, 198, 199, 
 200, 202, 204, 206, 207, 208 
 
 , melting, in nitrogen under pres- 
 sure, 212 
 
 plates, rate of cutting, with the 
 
 carbon arc, 80 
 
 seam welding, 366 
 
 wire butt-weld, *250, 252 
 Stellite insert welding jaws, *357 
 , jaws used for welding, *356 
 
 -tipped roughing drills, *348 
 , welding, 343 
 
 Steps in the making of a large 
 
 reamer, *353 
 
 Stove parts, spot-welding, using 
 swinging bracket support, *288 
 
 pipe dampers, spot welding, *285 
 Straight, definition of, as applied to 
 
 edge finish, 113 
 Strap weld (arc), definition of a, 
 
 110 
 Stratton, Director of the Bureau of 
 
 Standards, 171 
 Strength of arc deposited plates, 104 
 
 weld, variation of, with 
 
 change of arc current, 
 102 
 
 welded joints, 91 
 
 welds, 140 
 
 cast iron welds, 131 
 
 resistance welds, 389 
 
 weld (arc), definition of, 116 
 
 of welded joints, 135 
 
 Stresses in arc welded joints, 92, 
 
 *93 
 
 , result of ' ' locked-in, ' ' 62 
 Strip welding jig, *376 
 Strohmenger-Slaughter process, the, 
 
 1,3 
 Structure of arc deposited metal, 
 
 *105, *106 
 
 electrolytic iron, character- 
 istic, *199 
 
 Studies in overlap and penetration, 
 *56 
 
INDEX 
 
 415 
 
 Studs, use of, in arc welding, 129, 
 ?130, *133, 144, 155 
 
 Successful welds, reason for, 138 
 
 Summary of the results of the study 
 of the metallography of arc-fused 
 steel, 212 
 
 Supervision of arc welders, 145 
 
 Surface, building up a, with the 
 carbon arc, *72 
 
 Suspended head spot-welding ma- 
 chine, 294 
 
 Swinging bracket support for spot- 
 welding work, *288, *292 
 
 Swivel head, portable spot-welding 
 machine, *293 
 
 Symbols, combination arc welding, 
 118, *119, *120, *121, *122, 
 *123, *124, *125, *126 
 
 used in arc welding, 109 
 
 "Tack," meaning of, 63 
 
 Tack weld (arc), definition of, 115 
 
 Tank, corrugated steel, welding by 
 
 machine, *236, 237 
 , how edges of, are welded, 237 
 
 seam, welded straight, *222 
 Tanks, arc welded, *137 
 Taper of carbon-electrode, 68 
 Taps, method of welding broken, to 
 
 remove from hole, *149 
 , removing broken taps, 150 
 Taylor cross-current spot welding 
 
 process, *8 
 
 spot-welding machines, *302, 
 
 *303 
 
 Welder Co., 303 
 
 Teapot spout, a finish welded, *380 
 
 welding jig, *380 
 
 Tee weld (arc), definition of, 112 
 Tensile properties of electrodes, 179, 
 
 180, 181 
 Tension specimen, appearance of, 
 
 after test, *183 
 Terminology, a brief, 63 
 Terms, elementary electrical, 398 
 Terrell Equipment Co., 296 
 
 Test blocks, formation of, for arc- 
 fused metal, *175, 176 
 
 Tests, the Wirt-Jones, on arc welds, 
 189 
 
 Thermal analysis of arc-fused steel, 
 210 
 
 characteristics of arc-fused iron, 
 
 210, *211 
 Thickness and weight of sheet iron 
 
 and steel, 321, 322 
 Thomson butt-welding machines, 
 
 *240, *241, *244, *245, *246, 
 
 *251, *254, *256, *345, *347, 
 
 *348, *351 
 
 Co.'s tests on butt- welds, 395 
 spot welds, 391 
 
 Electric Welding Co., 366, 395 
 , Elihu, 4 
 
 foot-, automatic-, and hand-oper- 
 
 ated spot-welding machines, 
 280 
 
 seam-welding machines, *367, 
 
 *369, *370, *373, *374, *375, 
 *376, *377 
 
 spot-welding machines, *226, 
 
 *227, *281, *282, *283, *284, 
 *285, *286, *287, *288 
 
 vertical mash welding machines, 
 
 *358, *359, *360 
 
 Three-roller boiler tube machine, 
 *332 
 
 Thum, E. E., 396 
 
 Time required to cut with the car- 
 bon arc, 78, 79, 80 
 Tit or projection method of welding, 
 
 *291 
 
 Topeka shops of the Santa Fe Kail- 
 road, 339 
 
 Tool parts arranged for welding, 
 *354, *355, *357, *361, 
 *364 
 
 , grooving to aid in welding, 
 
 *364 
 
 room butt-welding machine, *261 
 
 welding, the insert method of, 
 
 355 
 
 Tools, butt -welding, *350, *352, *354 
 Training arc welders, 47, 145 
 
416 
 
 INDEX 
 
 Transformer of butt-welding ma- 
 chine, 239, *240 
 Truscon Steel Co., 397 
 Tube rollers, boiler, *331, *332, *334, 
 *341 
 
 welding machine with built-on 
 
 rolling device, *334, *339, 
 *340, *341 
 
 -welding set for butt-welding 
 
 work,'*263 
 
 work, examples of, *88 
 
 Tubes, boiler, pressure required for 
 
 welding, 337 
 
 , , ready for flash weld, *329 
 Tubing automatically arc-welded, 
 
 *233 
 Tungsten ring machine arc-welded 
 
 to cold rolled core, *232 
 T-welding, 252 
 
 Twist-drill blanks just welded, *349 
 Two-spot welding machine with ro- 
 
 tatable head, 298, *299 
 Typical ammeter charts of operation 
 of Morton arc welding ma- 
 chine, *224 
 
 examples of prepared and fin- 
 
 ished arc welding work, *87, 
 *88, *89 
 
 - light spot-welding machine, *278 
 Types of welding outfits, 21 
 
 U 
 
 United Traction Co., shop repair 
 
 work of, 150 
 Universal spot-welding die-points, 
 
 *296, *297, *298 
 Unland, H. L., 214 
 Unsoundness of arc-fused metal, 
 
 microscopic evidence of, 193 
 Uealite crucible, 208 
 Using a flux for flue welding, 330 
 U. S. Light and Heat Co., 40 
 portable a-c, motor- 
 generator set, 
 *39, 40 
 
 Van Bibber, P. T., 324 
 
 Vertical mash welding machines, 
 *358, *359, *360 
 
 position defined as applied to 
 
 ship work, *114, 115 
 
 seam welding, 62 
 Volt, what is a, 398 
 
 Voltage, effect of, on arc welds, 1G9 
 Voltex process, the, 2 
 Vulcan Iron Works, repair of large 
 crankshaft by, 162 
 
 W 
 
 Wagner, 167, 169 
 
 Wanamaker, E., 84 
 
 Warping of parent metal caused by 
 
 deposit contraction, *59 
 Water-cooled die-points for spot 
 
 welding, *281, *283, *284, *286, 
 
 *288, *291, *296, *297, *298, *302, 
 
 *303 
 
 ''Water-pail" forge, the, 1, 3 
 Watt, what is a, 398 
 "Weaving," meaning of, 64 
 
 of arc, 52 
 Weed, J. M., 311 
 
 Weight of sheet iron and steel, 322 
 Welded and riveted joints, *389, 391 
 
 automobile hub stampings, *2'2l 
 
 rear axle housing, *222 
 Welder, points for the, to learn, 49 
 Welding boiler tubes by the electric 
 
 resistance process, 324 
 
 booth, 48 
 
 Committee electrodes, composi- 
 
 tion of, 107 
 
 the Emergency Fleet Corpor- 
 ation, 90, 104, 107, 109, 
 134 
 
 high-speed to low-carbon steel, 
 
 344 
 
 Mild Steel, paper on, 223 
 
 other than round tools, 354 
 - pipe coils, *256 
 
 rotor bars to end rings in a 
 
 special butt-welding machine, 
 263 
 
 Stellite, 356 
 
INDEX 
 
 417 
 
 Welding valve elbows on Liberty 
 
 motor cylinders, *268 
 Welds, arc, the Wirt-Jones tests on, 
 
 189 
 , good and bad arc, *100 
 
 showing poor and good fusion, 
 
 *60 
 
 , terms and symbols for arc, 109 
 
 ' ' Welt, ' ' meaning of, 64 
 
 Weltrodes, composition of, 86 
 
 , sizes of, 87 
 
 Westinghouse Electric and Mfg. Co., 
 38, 47, 66, 81, 269 
 
 single-operator portable welding 
 set, *38 
 
 Wheel, car, repairs, *157, *158 
 
 Wilson two-arc "plastic arc'" weld- 
 ing set, *33 
 
 - Welder and Metals Co., 33, 81, 
 88, 128 
 
 welding and cutting panel, *34 
 
 Winfield butt-welding machines, 
 
 *257, *259, 260, *261 
 - Electric Welding Machine Co., 
 260, 295 
 
 spot-welding machines, *291, 
 
 *292, *293, *294, *295 
 Wire to use to connect up seam 
 
 welding machines, 379 
 Wiring diagram for percussive weld- 
 ing, *271 
 
 Wirt-Jones arc weld tests, 189 
 Work clamps for butt-welding ma- 
 chines, *242, *243, *257 
 Worn and repaired crane wheels, 
 *221 
 
 motor shaft built up by auto- 
 
 matic arc welding machine, 
 
 *220 
 
 Z 
 
 Zerner process, the, 1, *2 
 Zeus arc-welding outfit, *42 
 

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