The Iron Age 1942-10-01: Vol 150 Iss 14

fa} f 194 rary ican production beginning deliver the volume munitions and equipment that will turn the tide war. Efficiency production, coupled with speed materials-handling, will bury the Axis under avalanche steel. Now for the first time hitting its stride, Amer- Whiting Victory Cranes are doing important job. The “DeLuxe” equipment short time ago has given place streamlined design and con- struction for quickest possible delivery. Every essential quiet operation and long life retained ... but non-essentials and extras are “out” for the duration. cranes are important your operations, will pay you get full information about Whiting Victory Cranes. Whiting Corporation, 15601 Lathrop Avenue, Harvey, FOR SAFETY’S SAKE send for copy the new Crane Operator’s Handbook just published Whiting, containing rules for the safe operation Overhead Traveling Cranes. Ir p OCTOBER 1942 VOL. 150, NO. VAN DEVENTER President and Editor BAUR Vice-President and General Manager ° Managing Editor, LIPPERT News Markets Editor, ROWAN Technical Editor, OLIVER Associate Editors Art Editor, WINTERS Editorial Assistants BENEDETTO Resident District Editors Washington Pittsburgh DONALD BROWNE PHAIR Chicago Clevel Detroit OSSOOD MURDOCK San Francisco Editorial Correspondents Buffalo Cincinnati FRAZAR RAYMOND KAY Boston Los Angeles HUGH SHARP JOHN McCUNE Milwaukee Birmingham SANDERSON ROY EDMONDS Toronto, Ontario St. Louis BACON Seattle ° DIX, Manager Reader Service Advertising Staff Blair nion Bldg., Cleveland Herman, Chilton Bldg., Philadelphia Hottenstein, Otis Bldg., Chicago Raymond Kay, 2420 Cheremoya Ave., Los Angeles, Cal. Leonard, 100 East 42nd New York Peirce Lewis, 7310 Woodward Ave., Detroit Ober, 100 42nd New York Robinson Johnson, Market Research Hayes, Production Manager. Baur, Typography and Layout ° ° ° Member, Audit Bureau Circulations Member, Associated Business Indexed the Industrial Arts Index. Pub- lished every Thursday. Subscription Price North America, South America and Possessions, $8; Foreign, $15 year. Single copy, cents. ° ° Owned and Published CHILTON COMPANY (Incorporated) Executive Editorial and Offices Advertising Offices Chestnut and Sts. 100 East 42nd St. just Philadelphia, Pa. New York, U.S.A. OFFICERS AND DIRECTORS MUSSELMAN, President JOS. HILDRETH, Vice-President GEORGE GRIFFITHS, Vice-President EVERIT TERHUNE, Vice-President VAN DEVENTER, Vice-President BAUR, Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR Secretary JULIAN CHASE, THOMAS KANE, Editorial Not Too Little, Nor Too Late Technical Articles High-Manganese Austenitic Steel Effect Over-Annealing Steel How Select Cutting Tools...... INSERT—Cutting Tool Selection Stretch Forming Speeds Aircraft Production INSERT—Four-Color Photo, Engine Piastic Assembly Jigs and Fixtures. Welding Solves Slab Mill Delay....... Sintered, Forged and Rolled Iron Powders. INSERT—Four-Color Photo, Marines ... The “Great Western Mineral Vault” INSERT—Four-Color, Parachute Troops Anodizing Tank Short Circuits Tropenas Converter for Light Castings.... Heat Treating Terms Occurrence and Production Molybdenum INSERT—Four-Color Insert, Convoy Ship Features Washington .......... The West Coast Fatigue Cracks Dear Editor News and Markets This Industrial Week News Industry Priorities and Prices Personals and Obituaries Machine Tool Activity Non-Ferrous Metals Scrap Markets Comparison Prices Meial Congress Preview Preview Metal Congress Activities Correlated Technical ASM, AWS, AIME, List Exhibitors Special Advertising Sections Steel Mill Equipment Metal Treating and Finishing. Machine Tools and Small Tools Pressing, Forming and Welding Accessory Equipment and Parts ° Products Advertised Index Advertisers Copyright. 1942. bv Chitten Company (ine.) This 101 103 104 105 110 122 124 126 222 223 226 229 236 242 245 303 347 443 Ul 475 | 580 ‘J a4 Type SX, combination timer, fully elec- tronic. For spot, seam or pulsation weld- ing. Where frequent changes of timing are necessary. THE IGNITRON TUBE PIONEERED WESTINGHOUSE Makes Possible Split-Second Timing The Westinghouse development the Ignitron tube has made possible make and break circuits noiselessly with split-second accuracy many 600 times minute without any moving parts. = Westinghouse 48—THE IRON AGE, October 1942 { ey SYNCHRONOUS TIMERS SYNCHRONOUS TIMING Starting and at zero point pro. duce even wove =, ‘ = 4 NON-SYNCHRONOUS TIMING Random switching may 4 Where thin pieces metals with critical fusion points are welded, random (nonsynchronous) switching responsible for high rate rejects. Unpredictable transients mean unpredictable heat—burn through, warping, and even cold welds. Westinghouse Synchronous Timers eliminate these transients—they start and stop current always the zero point the current wave, later (when heat control used). result, each weld duplicate the preceding one because its wave form the same. With these Westinghouse Timers, you can mass-pro- duce short-time welds uniform strength and sound- ness. Metallurgical characteristics can controlled (stainless steel will not lose its stainless properties) and appearance improved holding indentation minimum. There’s Westinghouse Control that will fit your present requirements, whether it’s production seam welding only, combination spot, pulsation, and seam welding. Ask your Westinghouse representative for the facts about this precision electronic control. Westinghouse Electric Mfg. Co., East Pittsburgh, Pa., Dept. 7-N. j. 21225 THE Not Too Little, Nor Too Late the past years, American industry has had the unique distinc- tion being three places once, continuously and simul- taneously. has been the frying pan, back the eight ball and the doghouse. record. had been maligned, mauled, mishandled and mayhemed poli- ticians, reformers, labor leaders, left-wingers and mud slingers until the average employer felt like outcast society and was tempted wear CIO button show that his parents were married. Thank goodness, the doghouse days the industrialist are nearing end. The cranks and crackpots keep him there much longer. basis and with Army-Navy draped around its neck for good conduct. Army-Navy like Maritime Commission Awards are given only those concerns that have beaten their schedules. concerns who have done more than Uncle Sam expected them when put the heavy Industry from the doghouse strictly performance loads their shoulders. OCT. 1942 For the past six weeks average more than such awards per week have been made American industrial concerns. During one ° ° recent week there were over 100; last week over 60. America can rightly proud the quality both management and labor which has ably ESTABLISHED 1855 delivered the goods. But management and labor could not have done without materials. And this brings into the picture the metallurgists America This war essentially war metals. Not merely war iron and steel but myriad other metals which are called for the almost infinite inventory Mars. Mars respecter persons, but has high regard for metal- lurgists. think that and his associates will hovering over the Auditorium Cleveland next week, find out what you gentlemen the American Society for Metals, American Welding Society, American Institute Mining and Metallurgical Engineers, and Wire Association have done provide America with the sinews war. And think that Mars will astonished what sees. And perhaps, little later, more astonished what has not seen. For thanks our metallurgists America, this country now position say: “not too little nor too late, but enough and time.” } | | | j | | | - | i f 4 Inland loaders cheer plates for Liberty ships are Inland Men and Mills Set New War Production Records New production records are short lived the Inland mills—where thousands skilled workers never cease striving produce more steel for America’s great war plants and ship yards. Some the latest records are—an all-time monthly high the blast furnace depart- ment; new record plant No. open hearth furnaces, made despite handicaps scrap quality and supply; enough plates for two Liberty ship hulls rolled one 24-hour turn the 76-in. continuous mill; new all- time plate record the 100-in. mill; new ship channel peak the 28-in. mill; four records two months the 14-in. merchant bar mill; record output the 24-in. bar and SHEETS STRIP TIN PLATE BARS plate mill, Inland’s oldest mill which made records World War and, new record for all Inland plate mills—enough plates one month for Liberty ships! Not outdone the mills, every ship the Inland fleet has broken its all-time cargo- carrying record. The Block, flagship the fleet, recently bettered its record for the seventh time this season, delivering cargo 16,369 tons iron ore the Inland mill docks. These records are the answers Inland men America’s call for more plates and channels for ships, more bars for guns, more billets for shells—more steel back the efforts our fighting men. PILING RAILS TRACK ACCESSORIES REINFORCING BARS ssa placed, stull hot, into steel gondola. As ‘ RUSSELL FRANKS, BINDER, and CHARLES BROWN Union Carbide Carbon Research Laboratories, Inc., Niagara Falls THE trend structural design during recent years has been take advantage high strength materials or- der obtain decrease the weight the finished structure sacrifice Steels high strength have been developed save unneces- sary weight mobile structures, such airplanes, high speed trains, trucks and truck bodies. The upward trend using high strength steels has been particu- larly marked aircraft, which reduction weight contributes greater load carrying capacity, speed and increased dis- tance over which airplanes can travel. The steels developed far for this purpose have been per and per cent chromium—7 per cent nickel types steels. possible develop these cold- rolled stainless steels minimum tensile strength 185,000 Ib. per sq. minimum Strength (0.2 per cent offset) 140,000 per sq. in., and elongation least per cent in. Similar properties are developed compression, ticularly after application the low temperature heat treatment about 200 deg. (392 deg. F)? Cold-rolled stainless steels High Manganese Austenitic Steels This new type steel has extremely promising possibilities for construction and for other structures. The preliminary physical data, shown for the first time herein, indicate that the cold rolled manganese and manganese- chromium steels are amenable forming, drilling, machining, are easily welded, and have strengths equal the best stainless steels with serious loss ductility. these types have been used suc- cessfully structural members for aircraft, and building high speed trains well lightweight, high-strength struc- tures. Thin sections the steels can used without the necessity protecting their against atmospheric deterioration, which represents valuable asset. The excellent spot welding char- acteristics the cold-rolled stain- less steels has further added their value for lightweight, high- strength structures, these elim- inate large extent the neces- sity for using riveted structures. The high modulus elasticity the steels, which important property steels general, has made them ideal material for structural members lightweight high-strength structures. investigation has resulted the development series steels that have mechanical prop- erties similar those the stain- less steels even though certain the new steels are not resist- ant corrosion. was thought that many applications this would serious handicap the surfaces can adequately protected against deterioration under atmospheric conditions. has been found that when certain percentages manganese are added steel relatively low carbon content, austenitic steel obtained which high strength after cold rolling, both tension and compression. Inasmuch these high man- ganese steels are austenitic character, necessary cold roll them obtain high strengths rather than apply heat treat- ment such required for rais- ing the strength ordinary steels. Investigation these manganese steels has brought light, will shown the dis- cussion, three series materials that will develop basically the same high strength cold roll- ing the stainless steels ordinarily used for struc- tural purposes but which vary widely regard their resist- ance corrosion. The first series consists the THE IRON AGE, October 4 ° per cent manganese steels con- taining small addition nickel (up per cent) copper (up per cent) both, which rust under tions, whereas the second consists steels similar nickel and copper contents and about per cent chromium, which greatly retards progressive rust- ing under normal atmospheric conditions. The third series con- sists per cent manganese steels containing about per cent chromium, which sufficient impart high degree resist- ance staining inasmuch all manganese the chromium solid solution the austenite. the development work these steels, was found that the addition manganese alone ordinary low-carbon steel was in- sufficient produce metal with the desired properties regard cold rolling. The steels required were those that would crease hardness too rapidly too slowly cold rolling, but moderate rate give high strength with satisfactory duc- tility. was learned that the content was kept be- tween per cent and about per cent, with carbon content not greatly exceeding 0.35 per cent, the steels could more readily cold rolled than the manganese content and the carbon content higher. previously stated, additions small percentages nickel and copper were made produce sufficiently stable austenitic steel high-manganese content, with the result that the metal could cold-rolled sufficiently give the necessary strength and good duc- tility. The different types per cent manganese steels were hot Fig. curves for steel containing 16.30 per cent manganese, nickel, copper, 0.27 silicon, and 0.10 per cent carbon. Reduced per cent cold rolling; heat treated 1000 deg. Curve longitudinal direction rolling, tension; curve longitudinal direction rolling, compression; curve transverse direction rolling, compression. | | Strain, in. per Reduced per cent cold rolling, longitudinal direction. Reduced per cent cold rolling, transverse direction. Curve cold-rolled, tension; curve and heat-treated 200 deg. C., tension; curve cold-rolled, compression; curve and heat-treated 200 deg. C., compression. 52—THE IRON AGE, October 1942 Tangent modulus, Ib. per Fig. 2—Tangent modulus curves derived from stress-strain curves for steel H-204 containing 16.49 per cent manganese, copper, 0.22 silicon, and 0.10 per cent carbon. Fig. 4—Tangent modulus curves derived from stress-strain curves for steel H-689 containing 15.62 per cent manganese, 3.24 chromium, 1.00 nickel, copper, 0.30 silicon, and 0.20 per cent carbon. Tangent modulus, per Fig. 3—Tangent modulus curves derived from stress-strain curves for steel containing 16.30 per cent manganese, nickel, copper, 0.27 silicon, and 0.10 per cent carbon. @ Tangent modulus, Ib. per Fig. 5—Tangent modulus curves derived from stress-strain curves for steel H-604 containing 16.48 per cent manganese, 3.10 chromium, 1.83 nickel, 0.68 copper, 0.21 silicon, and 0.23 per cent carbon. Curve Reduced per cent cold rolling and heat-treated 1000 deg. C., compression; curve per cent cold rolling, longitudinal direction, compression; curve reduced per cent cold rolling and heat-treated 200 deg. C., longitudinal direction, compression; curve per cent cold rolling, transverse direction, compression: curve 5—reduced per cent cold rolling and heat-treated 200 deg. C., transverse direction, compression. various thicknesses, which were investigated for tensile and com- stress-strain character- istics. The tests were made the longitudinal and transverse direc- tions rolling, both the as- cold-rolled condition and after heat treating from hr. temperatures about 200 deg. (392 deg. F.). The tensile tests were made standard A.S.T.M. samples using suitable gages measure the strain different stress levels. The compression tests were made the cylinder which consists briefly determining the compressive stress-strain characteristics cylindrical sample having slen- derness ratio about and diameter thickness ratio about 40. both the tension and compression tests the loads were applied with 60,000 lb. Baldwin- Southwark testing machine. The gages were left the samples until was possible determine the proportional limit 0.01 per cent offset and the yield strength 0.2 per cent offset,* but they Navy Department Specification No. 47821. were before the sample was fractured. The results tension and com- pression tests made annealed thick strip samples the per cent manganese steels modified with small percentages copper and nickel, with and without cent chomium are presented Table They show that the annealed condition which ob- tained heating the steels for several minutes 1000 1050 deg. (1832-1922 deg. F.) and air cooling, all the steels are quite soft and have high ductility. The results further show that after reducing the steels about per cent cold rolling, they develop high yield strength both ten- sion and compression, which improved when steels are stress relieved heat- ing from hr. about 200 deg. (392 deg F.), followed THE IRON AGE, October 200 200 | air cooling. beneficial effect the low temperature heat treatment the ductility the steels especially marked, and shows that this treat- ment will aid their fabrication into structural members. For the sake brevity, all the stress-strain curves relating the data Table are not pre- sented. Only those representing the per cent manganese steel containing about per cent nickel and per cent copper are given because they are typical for the steels the group, which possess considerable resistance gressive rusting when per cent chromium present. The stress- strain curves for this steel the annealed condition, and after re- ducing per cent cold-rolling, are illustrated Fig. The data this figure reveal that the longitudinal direction rolling, the cold-rolled steel has some- what lower acteristics than the transverse direction rolling, whereas tension, the stress-strain charac- teristics are quite similar both directions rolling. The tangent modulus curves for this steel and the other steels containing additions nickel and copper with per cent chromium are moduli curves that all these cold-rolled steels have properties compression similar those the cold-rolled stainless steels compression. The important effect the low temperature heat treatment (200 deg. C.) clearly demonstrated moduli curves. every instance application makes possible for the steel withstand higher stress given modulus. These curves also bring out that the initial tangent modulus the heat treated steels the cold-rolled condition the order million lb. per sq. in. Similar tests were made the per cent manganese steel con- taining per cent chom- ium, and the results are given Table II, and Figs. and shown that the steel has high ductility and soft the an- nealed condition, and can cold- rolled high strength without too great sacrifice ductility. fact the data for this steel indi- cate that possesses somewhat higher ductility with strength than some the other 54—THE IRON AGE, October 1942 | | | | | | Strain,in per in. Reduced per cent cold rolling, heat treated 1050 deg. Curve longitudinal direction rolling, tension; curve transverse di- rection rolling, tension; curve longitudinal direction rolling, compression; curve transverse direction rolling, compression. 200 a oO Stress, 1000 per > oO Strain, in. per in. Reduced per cent cold rolling, transverse direction Curve cold-rolled, tension; curve and nickel, 0.20 silicon, and steels. The initial tangent modu- improving both the yield strength lus this steel approximately and ductility again evidence, million lb. per sq. in. both the percent elongation both tension and compression. can the longitudinal and transverse said that general the stress- directions rolling, especially strain characteristics this steel the latter, are almost doubled are quite similar those the this treatment. per cent chromium and per important requirement for cent nickel steels after cold roll- steels this class that they ing. The beneficial effect the capable being machined, bent, stress-relieving heat treatment and formed into various articles. compression; curve and heat-treated 200 Fig. curves for steel SL-190 containing heat a 120 Stress, per sq.in Strain, in. per in. Reduced per cent cold rolling, longitudinal direction. heat-treated 200 deg. C., tension; curve cold-rolled, eg. C., compression. 15.76 per cent manganese, 12.25 chromium, 0.27 0.14 per cent carbon. has been found that all the steels can turned, drilled, Shaped, and sheared without dif- ficulty provided their carbon con- tents are not too high. The carbon contents discussed the paper are satisfactory for these opera- tions. Higher carbon contents are detrimental bending and form- ing, and especially transverse bending, but the carbon con- in. per in. Reduced per cent cold longitudinal direction. tent controlled shown, the steels can bent through angle 180 deg. without danger cracking. would expected from the elongation values, the low temperature heat treatment also improves the bending proper- ties the cold-rolled steels. Another important requirement for these steels concerns their spot welding properties. Tests made this connection showed that the various per cent man- ganese steels could success- fully spot welded under the con- ditions ordinarily employed the cold-rolled The tests were made 0.035-in. thick strip, and the welds exceeded the strength 1500 for single spots, the minimum requirement for stainless steel strip this thickness. Tests were made annealed 0.035-in. thick strip samples the steels sub- normal temperatures, and the re- sults are given Table III. The bend tests the annealed samples were made over radius equivalent the thickness the strip, while the bends the cold- rolled samples were made using radius equal three times the thickness the strip. The results show that none the steels be- came extremely brittle any the temperatures down -65 deg. (-85 deg. F.) either the annealed cold-rolled condition, although the per cent manga- nese steel containing per cent copper did lose some ductility. The data further show that with small additions nickel and copper, and per cent chromium, the per cent manganese steels retain their ductility unimpaired temperatures down -65 deg. (-85 deg. F.), which im- portant consideration when, for example, airplanes fly high alti- tudes. also pertinent that the per cent manganese and per cent chromium steel retains its ductility during exposure these low temperatures. Similar bend tests were made cold- rolled samples the steels given the 200 deg. (392 deg. F.) treatment and equally satisfactory results were obtained. brief summary the data given herein shows that the rela- tively low-carbon per cent manganese steels with small addi- tions nickel and copper can cold-rolled high strength with- out serious loss ductility. These steels are not free pro- gressive rusting, but their resist- ance atmospheric corrosion greatly improved adding about per cent chromium, which ren- ders the steels more resistant progressive rusting. The per cent manganese steel containing about per cent chromium can also cold-rolled high strength with retention good ductility. This steel has high THE IRON AGE, October 1942—55 180 Tangent modulus, Ib. per sq.in Curve reduced per cent cold rolling, and heat treated 1050 deg. C., compression; curve reduced per cent cold rolling, longitudinal di- rection, compression; curve reduced per cent cold rolling, and heat treated 200 deg. longitudinal direction, compression; curve duced per cent cold rolling, transverse direc- tion, compression; curve reduced per cent cold rolling, and heat treated 200 deg. C., trans verse direction, compression. Fig. 7—Tangent modulus curves derived from stress-strain curves for steel SL-190 containing 15.76 per 160 120 tress, per sq.in. Tangent modulus, 1,000,000 Ib. per sq.in Curve reduced per cent cold rolling, longi- tudinal direction, compression; curve per cent cold rolling, and heat treated 200 deg. C., direction, compression. cent manganese, 12.25 chromium, 0.27 nickel, 0.20 silicon, and 0.14 per cent carbon. resistance atmospheric corro- improved application the peratures (down -65 deg. sion and quite resistant low temperature heat treatment -85 deg. F.), which are important straining under such conditions, 200 deg. (392 deg. F.). This assets steels for lightweight which make suitable for light treatment benefits the ductility high-strength structures. construction when adequate pro- and bending properties the BIBLIOGRAPHY tection against atmospheric de- cold-rolled steels and should terioration surface coating not feasible. thermore, the istics all these steels the istics and cold-rolled condition are definitely applied for optimum results. Fur- steels welding character- not become brittle when exposed subnormal tem- Cold Rolled “Effects Low-Temperature Heat Treatment Elastic Properties Austenitic Steels,” Russell Franks and Binder, Transactions American Insti- tute Mining and Metallurgical En- Stainless TABLE Tension and Compression Test Data Obtained 0.035-in. Thick Strip Modified Austenitic Manganese Steels c §= Chemical Composition, Per Cent H204 16.49 0.22 0.10 H641 16.30 1.14 1.11 0.27 0.10 3 a 28 H604 16.48 3.10 1.83 0.68 0.21 0.23 3 A 28 H689 15.62 3.24 1.00 1.08 0.30 0.20 Annealed heating for several minutes 1000 1050 deg. (1832-1922 deg. F.) and air cooling. Lb. Per Sq. In. Tensien Compression 28,000 38,000 128,800 85B heated hr. 209 deg. and air cooled. Buckling Stress, | Lb. Per Sq. tn. 206 219 202 .300 160 173 202 74,000 173 ,000 198 ,000 56—THE IRON AGE, October 1942 200 TABLE Tension and Compression Test Data Obtained 0.035-in. Thick Strip Austenitic Manganese-Chromium Steel Tensile Compression L190 15.76 12.25 0.27 0.20 0.14 30,000 142,800 82B ,000 79,200 heating for several minutes 1000 1050 deg. (1832-1922 deg. F.) heated hr. 200 deg. and air-cooled. air cooling. gineers, Iron and Steel Division, vol. 140, 1940, pp. 443-458. and Compression Stress- Strain Characteristics Cold-Rolled less Steels,” Russell Franks and Binder, Journal the Aero- nautical Sciences, Vol. No. 11, Sept., 1942. “Tensile and Compressive Prop- erties Some Stainless Steel Sheets,” Aitchison, Walter Ramberg, Whittemore, National Standards, Journal Research Paper RP-1467, March, 1942. “The Stress-Strain Cold-Rolled Austenitic Stainless Steels Compression Determined the Cylinder Test Method,” Russell Franks and Binder, Proceedings, M., June, 1941, Effect RECENT symposium, held the British Institute Phys- ics, brought light interesting study the effects over-anneal- ing steel the magnetic quali- ties the finally hardened steel. The examination was conducted hardened magnet, one with good and one with poor magnetic prop- erties, and similar study two softened steels, one being over- annealed. The X-ray technique consists subjecting the specimen nar- row vertical beam and photograph- ing the side reflections flat piece film placed facing the sam- TABLE Results Bend Tests Subnormal Temperatures the Per Cent Heat No. H604 H689 16.49 16.30 16.48 15.62 15.76 Composition, Per Cent 1.14 3.10 1.83 3.24 1.00 12.25 0.27 1.13 Manganese Steels 0.10 Reduced per cent rolling 0.10 Anneaied* Cold reduced per cent 0.23 Annealed* Cold reduced per cent rolling 0.20 Annealed* Cold reduced per cent 0.14 Annealed* Coid reduced per cent Bend** Without Failure Room Temp., 180 180 180 180 180 180 180 180 180 180 Heated several minutes 1000 1050 deg. deg. and air cooled. Samples bent both directions 180 100 180 180 180 180 180 180 180 180 120 180 100 180 180 180 180 180 180 Over-Annealing Steel ple. this method all four sam- ples were examined. The two hard- ened magnets showed differences except that distortion was present varying amounts, even though their respective hard- ness values showed difference which the about 200 points the the that the pre-heating time, the tempera- Diamond Hardness scale. The steels the softened condi- tion, however, showed striking dif- ferences indicating that prolonged heating increases formed carbide and promotes crys- talline growth both the carbide and iron phases. Further examina- tion proved that the steel having softening normal amounts formed the very small crystalline structure and had good magnetic properties. The annealed specimen. The reason for the poor magnetic properties the hardened normal over- steel ture from which the steel hardened, does not allow the whole the precipitated carbide re- enter into solid solution. Thus, the amount rapid cooling hardening operation cannot produce the maxi- mum hardness expected with correct heating schedules. sequence, the magnetic properties con- the steel are below those for the and fully hardened steel. THE IRON AGE, October 1942—57 ] { 4 Seam Welding Seam welds are now being made thin gage steel the rate 140 ft. per min., using direct current rectified from three-phase a.c. source. Tripling the speed con- ventional a.c. machines puts this d.c. seam welding proc- ess entirely new competitive position regards other methods joining sheets and opens applica- tions never before considered for resistance welding. ° DIETZ The Taylor Winfield Corp., Warren, Ohio THE trend toward increased manufacturing speeds and lower has caused manufacturers turn more and more resistance welding. The welding industry, turn, has found necessary im- prove and refine its product meet this demand and where possible anticipate future demands. Seam welding frequently used produce leak proof joint be- tween two sheets metal. has been commercially done, has had very definitely limited speed, due the cycle current. For example, two pieces 0.024 in. sheet steel require about spots per in. make gas tight seam weld. Since each half cycle makes spot, this limits the speed ap- proximately ft. per min. thinner materials the spots should smaller and, therefore, should closer together overlap suffi- ciently. For this reason the limit ing speeds would lower. There are two ways which this diffi- culty can circumvented. High frequency current will make the spots closer together. Direct cur- rent will make continuous seam. Currents frequencies higher than cycles increase the other difficulties encountered nating current welding. Inductance remains essentially constant and hence the inductive reactance var- 58—THE IRON October 1942 ies roughly the first power the frequency. The resistance the heavy sections copper which form the throat welder also shows appreciable increase with increase frequency. The exact function resistance related frequency varies with respect the shape and size the copper section, that cannot readily determined. The high line-de- mand caused high inductive re- actance can compensated for the use condensers, but nothing can done about the increased loss due the higher alternating current resistance. Any steel the throat high frequency welder, whether part the construction the machine the material being welded, would subject excessive inductive heat- ing and would greatly affect the impedance the machine. Direct current not affected the inductance the throat welder after steady state, where E/R, has been reached. (Ap- proximately 0.016 sec. the aver- age welder.) This gives the me- chanical designer much more free- dom than has had with any other type energy. Resistance voltage drops are also greatly reduced, be- cause the current distribution uniform throughout the copper section. satisfactory source direct current for welding must meet rather specialized conditions. must have low internal impedance and high current capacity. must compact. must have long life and free from excessive ser- vicing. Voltage and current must not vary from one application load another. The voltage drop through mer- cury tubes constant approxi- mately volts. This several times the voltage necessary for seam spot welding and would make very inefficient circuit. Ro- tating generators would costly and would probably introduce com- mutating difficulties. Armature reaction direct current gen- erator causes reduction voltage load comes on, weakening the field. When the load removed, the field does not immediately re- cover and may still this weak- ened condition when the load again applied. This would result non-uniform welds. Switching welding currents (as high 50,000 amp., more) would also produce serious switching difficul- ties. Storage batteries would give rise the same switching prob- lems generators. They would require frequent servicing and addition would require some form charging circuit which would either charge the batteries continu- ously would charge only during the idle time. Dry however, when connected form three- phase full wave rectifier, seem meet the above mentioned require- ments better than any other direct current source. Their inherent low voltage and high current character- istics make for good efficiency. Several combinations materials produce electrical valve action, but commercially available ap- paratus the familiar copper oxide rectifier and the copper sulphide magnesium rectifier have far appeared best suited weld- ing service. The reliability both types well established and their high current, low voltage ratings volts) are ideal for welding. Rectifier junctions may parallel- quite satisfactorily, thus making | a | | | y Fig. shows schematic diagram the power circuit typical direct current welder with tapped transformer primary for heat con- trol and switching device for appli- power. single-phase a.c. welding, transient currents cutting different parts the voltage wave the start the are not uniform and produce non-uniform weld, especially short time spot welds, unless syn- chronous timing used. This necessitates the use costly con- trol equipment. Starting differ- ent points three-phase voltage wave does not “show through” the rectifier since each the three phases will hit three different points the voltage, 120 electrical degrees apart. The oscillogram, Fig. shows this uniformity direct current with random start- ing with respect the a.c. input. automatic high speed seam welder now satisfactorily weld- ing two thicknesses 0.011 in. sheet steel the rate 140 ft. per min. with direct current, using copper oxide rectifiers. The design this machine such that large sections ferrous structures actu- ally encircle the conductors the weld current. The design also re- quires that the rectifiers mount- beside the welder, that the effective distance from the current source the welding electrodes long length copper, the welding accomplished 1.5 volts measured the rectifier terminals. This production machine, built replace other methods making gas tight seam. saves vital materials and order compete Contactor Three phase transformer primary with taps for heat Three phase secondary 7, Three wav bridge type rectifier horns and electrodes Fig. diagram the power circuit typical d.c. welding set-up, using three-phase dry disk type recti- fier the the welding transformer. Fig. 2—An oscillogram the circuit shown schematically Fig. Note that stabilized condition d.c. voltage and current reached brief instant and that the current build does not vary with random starting the a.c. voltage wave. with the previously established process, must run near the 140 ft. per min. speed, which about three times the maximum speed possible with 60-cycle weld- ing. comparison line demands conventional 60-cycle welder with 48-in. throat, 8-in. horn spacing, and in. diameter horns, with identical setup energized with direct current, shows the d.c. weld- have distinct advantage over the other. 15,000 amp., the a.c. welder draws 111 kva. single phase, while properly designed rectifier con- nected the platens the same welder draws only kva., three phase. commonly known that three-phase load produces less line disturbance than the same single-phase load. conclusion, appears that di- rect current applicable most resistance welding problems. proving itself every day stored energy welders. current from steady output source, such rectifiers, the only type energy that could have been used the particular high speed seam welder mentioned earlier this article. many instances the cost the equipment would make uneconomical use rectifiers, but the other hand already has opened new field resistance welding the form extremely high speed seam welding. Analysis difficulties encountered other applications, indicates that may advantageously used many places. THE IRON AGE, October 1942—59 y ; \ 2 ZN \/ SINCE there are many types cutting tools available for use, be- comes important se- lect the best type tool for particular job order se- cure the greatest machining efficien- cy, longest tool life and the lowest machining costs. During years experience with cutting tools, the writer has been faced countless times with the decision what type tool use. Through trial and error and subsequent reasoning why certain type tool did better than another type, was found that the correct answer fol- lowed certain pattern created the three basic qualities which all cutting tools have, namely: Room temperature hardness hardness (3) Toughness was invariably found that the most efficient tool excelled one two the three basic qualities that was most needed for the job in- volved. For instance, carbide tool could not used take very heavy cut tough steel casting because tool breakage. Why did the carbide tool break? The stresses produced the cut due the high tensile strength the casting and the heavy cut were more than what the toughness the carbide tool could stand. Hence, such job the proper type cutting tool had cope with the great cutting stresses. This condition dictated the use 18-4-1 high speed steel with hard- the other hand, light cut aluminum would not require tool with much toughness since alumi- num has comparatively low tensile strength and the tool would not need much red hardness, since such cut would generate relatively little heat. Therefore, tool with IRON AGE, October 1942 The author who compiled the chart the facing page cutting tool specialist. has been cemented carbide tools from their first beginnings this country inasmuch worked with Dr. Samuel Hoyt and others General Electric Co. the initial use cement- carbide tools 1925, many years before the Carboloy Co. was formed. Mr. St. Clair started the two-year factory training course G.E. Schenectady shortly after his graduation University Maine. was during this course study cutting tools became hobby and constant source interest. When the Carboloy Co. was formed 1929, Mr. St. Clair went Philadelphia branch manager. 1937 was established Newark, J., Eastern manager. Newark, set school for Carboloy tool users. Mr. St. Clair formed the General Tool Die Co. 1939 for the pur- pose manufacturing all types cutting tools. 1940 worked out two new processes tipping high speed steel brazing welding hardened pieces low shanks. These processes have been de- scribed THE IRON AGE, March and Aug. 1942. Mr. St. Clair has also helped de- velop new type cutting alloy which described the accompanying text. high room temperature hardness would the most efficient, and the best choice would hard grade carbide tool. this wasn’t available, and H.S.S. was available, this H.S.S. tool should made hard possible give the best results since toughness would not required. Eventually, the writer began analyze each job done with respect the tensile strength the material cut and whether the cut was light, medium heavy. From this analysis could determined which basic quality tool must excel this work. How Select Efficient Cutting Tools LEO ST. CLAIR President, General Tool Die East Orange, choose type tool that would have this basic quality over and above other types tools. From experience this method proved sound. One day this procedure ing explained tool engineer who had called the writer analyze particular machining job. suggested that these ideas could put down simplified chart form, would excel- lent guide. The result this sug- gestion the chart shown the opposite page. This chart was publication. From such field tests came very valuable suggestions the matter presentation and simplification, which have been in- corporated it. The centrifugally cast alloy ma- terial listed type No. the table deserves some further expla- nation. Its trade name Kut Kost and was introduced the General Tool Die Co. about six months ago. Even though two years laboratory testing showed that brand new cutting material had been developed, its introduction was made very cautiously one plant only. This plant had particu- larly difficult cutting problems. The results secured compared with high speed steel tools, were very satisfactory. also stood the tough operations where carbide tools were underspeeded and where breakage and chipping was exces- sive. Tests have since been made other plants and these have also writer’s company now preparing introduce this new material broader basis. The price will little above the price the present cast alloy tools having high percentages cobalt, chromium and tungsten. Kut Kost contains high per- centage tungsten and cobalt, per cent boron along with other metals not ordinarily associated with cutting materials. The boron forms boron carbide particles which are harder than tungsten carbide a Mg Ay | ASN TOOL SAdAL tame a Ba at or aw == - e Lid — i a ( | LSOW -10dw! saworeq ssauyBnoy yoay YyBiy (ul (ul /g IDIOHD ssauyBno; 4104 sauinbas puo yoay yBiy sadaap si }! ‘apiquos) 4430S -1D*) P4DH (§ND 4O BZIS OF BNP sadaap $i 4n> Aojjy jooy 1001 apiq (ur voy sadaap si }! ‘@prquos (ul @, P42H wNnipaw—Puz 3DIOHD (‘ul uoys sadaap si 1331S AOTIV HONOL HONOL | < ' — aBojuarsad 0} mo Wilds lVw Cand azis puo Buieaq jousjow jo Ys Buays ajisuay PUO sj! Of ANP ss@euyBNo, sasinbas LSOW (ur 9L/E yBiy anp ssaupsoy pas puo ‘ajisuay yBiy of anp ssauyBno sauinbas ind ul 9L/E uous sadaap 1901 (‘ul 9L/E IDIOHD jadaap si ‘apiquosy 40S 40 Of BNP Ssau (ul uow ssau yBnoy yonw Buiag jouajow 4o ayisuay yBiy of anp jyoay u 1331S 1331S (42 ssauyBnoy yonw auinbas Ajjoua uaB jou saop ing 4O pUNOWD 4104 5340949 4ND) 04 anp ssauyBno4s yonw asinbas Ajjosauab ; ~ : : i | puo Buiaq jouajow jo ajisuay aBojuarsad 0} mo SSINHONOL juajuo> 1001 P4PH wnipsw—puZz IDIOHD (ure, uoy 1331S ‘9 ‘0901 ‘OSOL particles. This combination al- loys gives the material some re- markable qualities. the first place, the hardness Kut Kost 1100 deg. several points har- der than room temperature and 1200 deg. its hardness just little below its room temperature hardness. the second place, its hardness can brought Rockwell heat treatment. Kut Kost centrifugally cast very high speed and hence ex- tremely dense and tough. The appearance fracture looks good deal like the fracture properly hardened high speed steel, that is, very close grain structure with silver gray, velvety appear- ance. Due its ability take very severe interrupted cuts, its toughness 61-63 Rockwell appears about the same 18-4-1 H.S.S. Its toughness 65-67 hard appears superior the cobalt high speed steel. 72-75 hard, its toughness, ap- parently greater than the ce- mented carbides. The material being supplied commercially grades, labeled and XV. There also fourth grade, XX, but will sold only restricted basis for specific applications since the ma- terial very hard and lacks tough- ness. The table shows the four grades, corresponding and typical applications for them. Columbium OLUMBIUM, like molybdenum, decreases the temper-brittle- ness special steels, according scientist, reported the U.S.S.R.’s Bulletin Academic Science. The carbides columbium and molyb- denum are dissolved back into the solid solution only very high tem- peratures (2200-2375 deg. F.), pointed out. During hardening steel from normal temperatures the car- bides columbium and molyb- denum (which absorbed some car- bon) exist the metal that form which they were present before hardening, relatively coarse particles. These carbide particles serve centers crystallization the coarse carbide masses during tempering steel and prevent ap- pearance new fine carbides which are the cause temper-brittleness. Table Kut Kost Hardness Rockwell Grade Application Vv 61-63 Heavy roughing cuts on ferrous metals, 1/32 to '« in. feed. Will take severe interrupted cuts tough irons and steel. Semi-finish and medium roughing cuts on ferrous materials, 0.010 to 1/32 in. feed. Heavy roughing cuts on non-ferrous materials; feed anything machine too} will stand. metals and duty non-ferrous mate- rials. Very light cuts on ferrous and non-ferrous materials. Will sold for specific applications only. The only difference the grades the Rockwell hardness since the composition the same for all grades. difficult lay down rules governing speeds and cause the most efficient speeds and feeds depend upon many factors such the material being cut, the depth cut and the condition the machine. speed about per cent that recommended for carbide tool operating under good conditions practical with these alloy tools. Increased feed from two four times that used carbide tools recommended due the great toughness the ma- terial compared with carbide tools. fact, the most efficient The presence columbium and molybdenum carbides decreases the degree super saturation the solid solution with carbon after hardening and retards the separa- tion the fine special carbides (chromium, manganese, etc.). The effect manganese proc- esses causing temper-brittleness connected not with its presence the solid solution a-Fe, but with the property forming slightly soluble carbides. Hardening from 2375 deg. and tempering 390-490 deg. for hours does not decrease the impact resistance increases (owing overheating) very little, compared with har- dening from normal temperatures with the same tempering. The slight decrease the impact resistance observed some cases (after har- dening from 2375 deg. and low operation this tool material takes place when the cut generating high heat due its increase hardness the higher operating temperatures. Failure Kut Kost tools will result from the improper choice hardness grade. Kut Kost tools can ground easily high speed steel tools and the same abrasive wheels. recommended that there “dub- bing off” the fine cutting edge medium roughing work and severe dubbing off the cutting edge heavy work. severe jump cuts, 45-deg. land can stoned the cutting edge. The width this land should from per cent the feed per revolution being used. Kut Kost the annealed state from Rockwell “C” hard. and consequently cannot ma- chined. Apparently the boron car- bide remains permanent solution material any softer. Because the difficulty casting the material. for the time being, only square and rectangular pieces are being cast. Round pieces will have ground from square pieces. Due the scarcity alloying material, Kut Kost will supplied solid bit only the sizes Larger size tool shanks will supplied tipped form, being brazed process. Decreaser Temper Brittleness tempering) the smaller the more columbium present the steel. Columbium decreases the tendency steel overheat. Nickel steel containing special carbide-form- ing elements has tendency for temper-brittleness when hardened from either 1690 2280 deg. Nickel and silicon-nickel steels con- taining molybdenum columbium are insensitive temper-brittleness only when hardened from compara- tively low temperatures which the carbides molybdenum and columbium cannot dissolve the solid solution Nickel and silicon-nickel steels containing mo- lybdenum columbium possess temper-brittleness the hardening temperature sufficiently high for the carbides molybdenum co- lumbium dissolve the solid so- lution. THE IRON October 1942—67 ’ | | | | : | | | | : Stretch-Forming stretch-forming double- acting hydraulic presses now being proved pro- duction. Some the inno- vations designed speed production and ease the difficulty stretching shal- low are described this article. THE proper choice making part im- portant the selection the proper material, especially when assurance more efficient production method de- sired. The difficulties sheet metal forming can best mini- mized analyzing the obvious troubles before they develop and the obscure troubles they devel- op, from the standpoint both the basic fundamentals shop application. Information the practical shop application “stretch-forming” somewhat scanty because the short time that this method has been use aircraft manufac- turers. The industry whole has been quick grasp worth- while ideas and methods; stretch-forming has been gaining popularity and has recently been promoted from the “idea stage” the “production stage.” The im- portance the development methods forming troublesome contours being uni- versally appreciated. Development engineers have been devoting good portion their efforts not only learning what can done with present stretch-forming equip- ment, but also upon what could accomplished with improved future equipment. They are rapidly re- ducing many “factors ignorance” dependable “factors experi- 68— THE IRON AGE, October 1942 ence.” Thus “knowing how” rath- than “knowing about” forming technique enables the shop meet the production schedules with inter- changeable assemblies. Lockheed Aircraft Corp. the double-acting hydraulic press, the absence specially designed stretch-form work, permits the part held firmly along two edges the punch forms the blank the desired contour. The set-up pictured diagrammatically eeds Fig. The punch attached the main and there fe- male bottoming die. The place the latter supporting the hold- down plates taken the heavy rails shown each side the punch. Both the rails and the hold- down plates are smooth, the latter being held under heavy pressure rods passing through the main ram th