The Iron Age 1940-11-14: Vol 146 Iss 20

NOVEMBER 14, 1940 VOL. 146 NO. VAN DEVENTER President and Editor BAUR Vice-President and General Manager Machine Tool Associate Associate Editor Editor Editor Art Editor Editor Emeritus Washington Editors MOFFETT JAMES ELLIS Resident District Editors T. C. CAMPBELL HERMAN L. KLEIN Pittsburgh Chicag Cleveland Detroit Editorial Correspondents Buffalo Cincinnati FRAZAR CHARLES POST Boston Son HUGH SHARP JOHN McCUNE Milwaukee Birmingham Toronto, Ontario St. Louis LEROY ALLISON Newark, Managing Editor News Editor Technical Editor Editorial The Silent Partners Technical Articles Salt Bath Heat Treating Flame Hardening Standardization Rustless Doubles Capacity Welded Joints Analyzed Polarized Light Sam Carbis Had Idea Carbide Tool Prices Corrugated Iron Porcelain Enameled New Gages and Small Tools Feature Reports the Assembly Line Washington News News and Market Reports News Industry Personals 105 Obituaries 106 Metal Working Activity 107 Comparison Prices 108 Summary the Week 109 The Industrial Pace 110 District Market Reports 112 Fatigue Cracks Free Industrial Literature Products Advertised Index Advertisers Copyright, 1940, Chilton Company Advertising Staff Emerson Findle Herman, Chilton Bldg., Philade!phia Hottenstein, 1912 Otis Bldg., Chicago Leonard, 100 42nd New York f Lewis, 7310 Weodward Ave., Detroit Ober, 100 East 42nd New York Don Harner, 1595 Pacific Beach, Cal. Member, Audit Bureau Member, Associated Business Papers Indexed the Industrial Arts Index. lished every Thursday. Subscription Price: United States and Possessions, Mex , Cuba $6.00; Canada, $8.50; Foreign, $12.00 a year. Single copy, cents. Machine Tool Activity Non-Ferrous Market Scrap Market and Prices Construction Steel Iron and Steel Prices Ferroalloys, Pig Iron Prices Warehouse Prices Sales Possibilities and Published CHILTON COMPANY (Incorporated) Publication Editorial and Office Executive Offices Chestnut and Sts., 100 East 42nd St., Philadelphia, Pa. New York, U.S.A. OFFICERS AND DIRECTORS MUSSELMAN, President Vice-President JOS. HILDRETH, GEORGE GRIFFITHS, EVERIT TERHUNE, VAN DEVENTER, BAUR, Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS KANE, HARRY V. DUFFY CHARLES J. HEALE n . 119 122 A. H. DIX, Manager Reader Service Your Fin right: Interior Mahon Hy- System installed The Defoe Finishing plant, Chi- Below: Products pass- through the Mahon the the same installation. Mahon Engineers Will Design Complete System production finishing today the right type equipment greater importance than ever before thorough engineering and proper coordination the various units equipment nec- essary the Cleaning, Rust Proofing and Finishing process absolutely essential insure satisfactory results continuous operation. That why manufacturers throughout the country, like the Defoe organization Chicago, turn their entire Finishing Equipment problem over Mahon engineers they with complete confidence—because, they know that Mahon engi- neers, backed seventeen years research, development and practical experience this highly specialized field, are better qualified design the type Finishing System that will Filter Spray Booth produce the desired results the lowest possible cost each ence, gained Mahon engineers through close contact with Exterior Mahon installation, production operation, available you. Call Mahon engi- neer now—consultation and study your requirements will not place you under any obligation. Mahon Baking Oven in- DETROIT CHICAGO stalled the roof The Defoe Finishing Company's plant, Chi- Thi thod Designers and Manufacturers Complete Finishing Systems, Metal Cleanin and Ovens Machines, Rust Proofing Machines, Hydro-Filter Spray Booths, Ovens saves much valuable floor space Types, Air Supply Dust Collectors and many other within the plant. Units Special Production Equipment. IRON AGE, November 1940 j | | The Silent Partners SEE the papers” that the Warner Swasey Co. Cleveland earned per share during the third quarter this year. Now there nothing very surprising about this, for all our readers know, this machine tool building concern has able management and lots business. But the account goes step further and discloses that the per share earned this company, the Federal levy was $1.10, leaving 83.5 cents available for dividends and surplus. course this $1.10 per share taxes Federal only and does not represent what the State and municipality take also. Again there nothing surprising the fact that Uncle Sam mak- ing heavy levy profits wherever they appear. The money has raised somewhere pay for our defense program well the ordinary costs Government. And better take out profits than out principal. The wage earners who work for Warner Swasey and other com- panies that are earning profit are not likely complain this tax icy the Government. They would rather see the money come from profits than from their breadbaskets which already carry heavy tax NOV. 14, 1940 load. for the stockholders, they any say the matter since they take the third helping, after Uncle Sam and the State have reached out for theirs. ESTABLISHED Now citing this particular company, not taking exception, 1855 for taxes per share many concerns today are higher than net-after- taxes per share. And the full effect the new tax bill comes into play, the concern which such not the case will probably the ex- ception. Business men will reconcile themselves this because inevitable under the circumstances. But think from this angle: Uncle Sam and labor are then the chief beneficiaries the earnings industry. Their claims are preferred. the third quarter 1940, per cent the efforts the Warner Swasey Co. were devoted earning profits for Uncle Sam and per cent them were devoted earning profits for dividends and surplus, after, course, subtracting the major efforts that went meet the payroll. Under these circumstances, with Government and labor the chief beneficiaries our American enterprise system, reasonable ask and expect that these big silent partners will exert every effort make and keep these enterprises sound and profitable? That thought think about while are talking about united America! | | | = f | = 2 | AS | 4 | | HEN you are faced with tough forming job turn Inland Sheets. They are being successfully used for extra deep draws, diffi- cult spinning operations, deep corner draws, etc., many leading manufacturers. Inland Sheets have become famous because they per- form well the most difficult jobs. One reason for this metallurgical coopera- tion. Inland extends this service its cus- tomers for the solution old well new forming problems. longer necessary select steel the costly and laborious cut- and-try method. Take the short cut—the way that gets quickest and best results—get Difficult Jobs Have Made INLAND SHEETS Famous touch with Inland. Let one our metallurgists visit your plant study your product and your sheet needs. will write specification that will followed the letter the Inland mill. You will get highest quality, uniform sheets that will fabricate economically, and make your products more acceptable point sale. You will then understand why Inland service and Inland Sheets are famous. yours difficult job, more than ever job for Inland Sheets. Write, call, your nearest Inland office. SHEETS STRIP TIN PLATE BARS PLATES FLOOR PLATES STRUCTURALS PILING RAILS TRACK ACCESSORIES REINFORCING BARS Paul, Louis, Kansas City, | molten salt bath has been recognized widely providing, through the immersion principle, group practical advantages heat treating that includes immediate and complete sealing the work from contact with the air, faster heating the work conduction, rather than radiation convection, and certain opportunities for doing selective hard- ening work under closely controlled conditions. Contributing broader and more general adoption the bath has been new operating factor —the direct heating the liquid salt means the own resistance the flow current between im- mersed electrodes.* This has, among several other advantages, increased pot life and greatly reduced general fur- nace maintenance. the Ajax-Hultgren electric furnaces, which use the electrode heating prin- ciple, this absence flame from di- rect impingement against pot walls has increased pot life from the usual one six weeks, more than year, many typical installations. automobile and affiliated parts indus- try there has been consequent con- *See THE IRON AGE, Oct. 15, 42; March 28, 1940, 48. 1936, stant increase interest this type equipment. Still further impetus interest the modern salt bath lies amounts minor revolution the tool steel field, where least one prominent manufacturer refers possible war-induced shortage tung- sten, explain switch now mo- lvbdenum tool steels and the recent adoption the electric salt bath heat treatment this material. Some mo- lybdenum steels decarburize readily atmosphere, even controlled atmos- phere, whereas this material and also cobalt steels are safe from decarburi- zation when immersed the protec- tion proper salt bath. The entire range heat treating operations from 300 deg. 2400 deg. bracketed available salt bath equipment. Applications include cya- nide hardening, liquid carburizing, hardening neutral baths, selective hardening and annealing, tempering, hardening high tools and dies, annealing, and treating age-hardening metals. More recently the salt bath has been developed brazing medium, and now use for heating steel rods, tubes and shapes for upset and press forging operations. Within the automotive industry, job Salt Bath Heat —In automobile and tool plants, liquid salt baths are finding wide application for cyaniding, carburizing, selective hardening and annealing, hardening high speed steel tools, etc. SHERMAN Detroit The Age lot and mass production applications are both found, along with some interesting examples single-purpose automatic installations, that are not likely found elsewhere very often. Reasons peculiar each plant have governed the selections equip- ment, but, the main, choice the electric salt bath determined con- siderations pot life and maintenance, elimination decarburization such materials molybdenum alloy steels and the high carbon types, already mentioned, adaptability selective heating, cleanness, external temperatures and better working con- ditions for operators around the in- stallation, reduction time cycle be- cause faster heating, and reduction sand blast required clean parts, etc. normal division electric salt bath installations into low-heat and high-heat groups occurs. majority the furnaces use fall the for- mer classification because the quan- tity and nature the materials being treated the lower (approximately 1450 1700 deg. F.) temperatures. These low-heat installations most fre- quently encountered are cyaniding, case hardening carburizing operations. The high-heat applications are con- THE IRON AGE, November 14, 1940—43 >. : i | | | | | a = | | ELEVATION Tap changing, insulation-- conveyor’ conveyor Supply conveyor return return return CROSS SECTION 44—THE IRON AGE, November 1940 continuous tion line drawings showing the mode travel the Chevrolet salt bath instal- lation Bay City. Two installations type handle 24,000,000 push rods each year. these | cerned with the treatment the usu- ally difficult high-speed steel tools and special dies. Packard Motor Car makes use electrically heated cyanide pot case-harden transmission synchro- nizer brake housings and oil pump gears, for selective hardening parts the transmission shifter forks, and oil- hardening clutch rings which weigh each. Regularly the charge either mixed batch forks and 15-20 gears, the clutch rings. Transmission synchronizer housings are case-hardened depth 0.005 in. and require time cycle min. The hardening the clutch ring takes half hour also. Treatment the clutch rings, plus heating ten fixtures which are immersed, costs about per for current used, estimated. The material SAE 1020 steel for all the parts ex- cept the clutch rings, which are 5140. been factor the heat treatment clutch rings, since the salt bath was put into use distortion rejections have been less than per cent. The indi- cation that the uniform heat the current agitated salt bath has mate- rially reduced the distortion tenden- Temperatures the Packard instal- lation range from 1450 deg. 1500 deg. the pots, which are weld- steel plate, with working space 12x24 in. Performance records show pot life approximately one year. automatic cyaniding operation performed more than 24,000,000 push rod ends each year the small parts plant Chevrolet City, Mich. Two furnaces are installed handle this work. This represents the heat treat- ing the two ends the valve push rods for more than million en- gines every months. The material has initial hardness Rockwell inspection for seams, the material cut off in. lengths Brown Sharpe cut-off machine and then run through slot-type, gas- fired furnaces heat each end sep- arately, cherry red heat. ends are upset three-stage dies Na- tional forging machines. One end upset form ball and the other has cup-shaped depression mush- roomed end. Sand blast follows the forging, and then the surfaces are coined, again National forging ma- chines. the cyaniding operations, the end the conveyor which carries valve push rods through two cyaniding and the quenching operations. Forty-eight push rods are placed rack one time and hung from the conveyor. THE IRON AGE, November 1940—45 salt bath pot for the treatment valve push rod ends. changeover from 100 per cent operation tungsten steel heat treatment molybdenum alloys, American Twist Drill Co., Detroit, makes use this installation. Cutting tools many sizes and weight are heat treated masse. Cleanness the finished tool—so they can easily checked for straightness—is one the advantages cited here. rods are put fixtures—48 rods time—and suspended from verse shaft, each end which sus- pended from chain conveyor the single-purpose, automatic cyaniding unit, each incorporating two Ajax- Hultgren furnaces. Two conveyors are used inside the furnace enclosure. One merely car- ries the fixture from the loading sta- tion upward the top the furnace enclosure, along the length the unit and down the far end, deposit the loaded fixture similar chain conveyor which carries through the heat treating process. When the fixture and rod are de- posited this second conveyor, the ends the rod, about in. the rod length, are immersed the cya- nide. Nine fixtures, containing total 432 rods, are thus suspended time rectangular welded steel pot which ft. deep and contains 800 Ib. salt. each new charge deposited the bath, the conveyor moves forward and lifts out one the nine fixtures, then dips into quenching water one batch rods. Between entering the cyanide bath and removal for the quench the period about min. Af- ter quenching, the rods are suspended over gas-heated hot plate remove all moisture. this stage—just after the quench 46—THE IRON AGE, November 1940 —an automatic turnover flips the fix- ture the heat treated portion the rod the top and the other end the rods are ready for the cyanide dip similar furnace pot the next stage along the conveyor. The turn- over accomplished when gear the fixture meshes with teeth rack the furnace structure the fixture revolved through 180 deg. The second cyanide bath similar the first, but blast air kept blowing over the surface the bath keep the heat from rising and drawing the finished upper ends the rods. Following the second quench, the rods are sprayed with soluble oil and unloaded from the conveyor. Use 1040 steel for the push rods presented problem decarburiza- tion which had guarded against. The salt bath has proved satisfactory and gives file-hard case (60 Rock- well about 0.002 in. thick. This, along with the ease selective hard- ening the push rods, led the choice the salt bath. The furnace temperature for cyanid- ing 1500 deg. Pot life this case, also, has proved about one year. Rejections from the surface harden- ing process are negligible, although distortion necessarily corrected be- fore the rods are put into service. Straightening the rods accom- plished with power-driven rollers later operation. the two cyaniding operations just described, Packard and Chev- rolet, over-all costs are reported lower than those encountered previously the same operations. second Chevrolet plant which making use electrically heated salt bath furnaces the motor plant Flint where the principal use for the installation the heat treating mo- lybdenum and tungsten high speed steels. The tungsten (an 18-4-1 ma- terial) treated get final hard- ness Rockwell 63-64, the molyb- denum steel (9-4-2) treated get hardness Rockwell 64-65, mo- lybdenum hot-work steel used for spe- cial extrusion dies, which must oper- ate high temperatures, treated give hardness Rockwell 58-60. this type work, Chevrolet has three electrically heated salt bath fur- naces single battery, including pre-heat, high heat and quenching pots, although indicated that oper- heat pots were provided keep mate- rials flowing more steadily the high- heat pot. Since all the materials treated here must tempered, drawn, three lead pots operating 1000 1150 deg. are provided. The charge for these pots, whether cutting tools special valve extrusion dies, approximately The pre- heat furnace operated 1500 deg. and the quench about 1250 while the high-heat furnace varied, depending upon the being heated. The molybdenum steels are brought 2100 2250 deg. and the tungsten materials are heated 2200 2350 deg. Similarly, the tem- peratures the lead drawing pots are varied obtain the desired hard- ness the finished parts. Considerable experimentation with salt has been done this installation. Use sodium potassium chlorides the pre-heat furnace, silicate the high-heat furnace, and combination carbonate and cyanide the quench furnace proved causing pits the surface tools. the other hand, the adoption cyanide salt for pre-heat and quench, with barium chloride properly rectified the high- heat furnace, proved more satisfactory regards surface condition the tools which are treated, but has caused some difficulty because the tools not come out the quench clean enough checked immediately for straightness. The difficulty that the time the tools are cleaned enough gaged for straightness, they have hardened that mechanical straightening difficult. Some light thrown this problem, however, technique which will discussed shortly. reported that the high-heat furnace this installation, electrode life about two weeks for each set- ting the electrodes, about six weeks total life; this regard, some- what longer electrode life obtained with the silicate than with barium chloride. However, maintenance high-heat pots has been very much reduced. Pot life considerably excess 2500 hr. maximum heat has (It the practice this plant, nevertheless, install new pot maximum 2500 hr.) Average life (high-chromium cast steel pots are used all high-heat furnaces) ap- proximately 2000 hr. The quench pot this installation has never been pulled and has been service ap- proximately two years. The pre-heat pot has service life about one year. This long pot life fairly typical the electric salt bath furnace. general, instances encountered the field show replacement life about year with cyaniding pot operating about 1500 deg. while high-heat equipment, operated between 2000 and 2400 deg. F., gives maximum pot life 2700 3500 hr. heat, with the average life determined, course, the specific operating conditions. Undergoing change-over from 100 per cent operation tungsten steel the heat treatment molybdenum al- loys, the American Twist Drill Co., Detroit, has experienced important differences its heat treating require- ments. The electrically bath furnaces were installed with the change-over (from tungsten molyb- denum) mind and the operations the plant are illustrative the exact- ing requirements treating high HREE Ajax-Hultgren electrically heated salt bath furnaces including pre-heat, the left, high heat the center pot, and quenching pot the right are used the motor plant Chevrolet Flint, Mich., for heat treating molybdenum steel and tungsten high speed steel. speed steel tools. The tools are selec- tively hardened the shank hard- ness 62-65 Re. This firm operates four Ajax electric salt bath furnaces—two naces (1400 1600 deg.), one high- heat furnace, and quench bath oper- ated 1100 1200 deg. Charges con- sist anything from one tool 400 time pots that are in. deep. The process consists the usual pre-heating essential before the tool subjected the extreme temperatures the hardening heat, then the high heat, and finally the quench, followed drawing Homo electric fur- nace operated 1050 deg. Use the salt bath for the quench accord with the general practice quench tool steels salt bath but also provides cleaning action which permits accurate checking the distortion present treated tools. This cleaning accom- plished through careful selection salts used. the high-heat bath, the American Twist Drill Co. uses Park Chemical Co. patented salt containing barium chloride and deoxidizer (sili- ca); the quench salt contains small amount cyanide and designed par- ticularly act solvent for the barium chloride. turn, the quench salt quickly soluble water the tool comes from the heat treating oper- ation extremely clean condition, suitable for checking and straighten- ing before drawing. Production costs are cause the small amount sand blast and shot blast that required this tool company’s high output drills, reamers and similar tools. Also, the company stated that less straightening required. The faster heating the salt bath has reduced operating time about per cent. Investigation reveals general pref- erence for unit furnace installation rather than the battery type enclosed single hood. This opinion the heat-treaters prevails least cases where mechanization not factor. This preference based the con- tention that periodical maintenance work more easily done each pot not necessary work close other pots which are working temper- atures. course, where the work not transferred from pot pot manu- ally, but moved mechanically the conveyorized installations, conceded that the furnace pots must located side side and that single enclosure satisfactory. The “control atmosphere” around the work and remarkable adaptability selective heat treating operations assure the continued use the salt bath, indicated, while the econ- omy, uniformity, flexibility and pro- duction speed embodied these in- stallations give promise continued development the art. THE IRON AGE, November 14, 1940—47 3 j | - i the subject can only considered general way, basic understanding the factors which cause distortion flame hardened parts vital im- portance determining the type part which can successfully flame hardened. The distortion which takes place result any hardening method usually caused strains set within the part. These strains are caused two basic factors, namely non-uniform volume increase caused the forma- tion martensite localized areas hot upsetting certain sections due uneven heating cooling rates. either the material method heat treatment such that the volume increase caused the formation martensite not uniform throughout the part, internal strains will set up. The two illustrations shown Fig. are typical parts such de- sign that strains caused this factor will produce distortion. the stresses due this volume increase are the only ones considered, would rea- sonable assume that they would comparable magnitude the above parts, even though they were produced entirely different procedures. both instances the Note: very complete discussion the stresses produced quenching steel parts appears the book Steel Frank Palmer. 48—THE IRON AGE, November 1940 Hardening Standardizatio HARTLEY Metallurgist, LeBlond Machine Tool Co., Cincinnati would tend elongate, and this action would resisted the base metal which did not have the martensitic structure, The second factor which must considered the strains caused the hot upsetting. the case the flame hardened specimen, Fig. 31-A, the base metal cold and only the surface layer heated. This layer tends expand when the heat applied, but sisted the cold base metal. Thus the top layer which being flame hardened hot upset. the hardened surface cools tends con- tract and become shorter than its orig- inal length. However, remembered that the volume change due the formation martensite in- creased the length the hardened layer. That is, the instance the hardened part the forces set due to volume change are counter- acted those produced the hot upsetting. However, will shown later that these forces not balance. the case the carburized part, 31-B, the entire section when the part quenched. The sur- faces exposed the quenching me- dium are cooled rapidly and tend contract. Since the core still hot hot upset. When the entire part reaches uniform temperature the core then tends have shorter length than originally had. That the case the carburized part the strains caused the hot upsetting must added those produced the volume change due the forma- tion martensite the case. The fact that the stresses part this general design are less hardened part than carbu- rized part indicated the figures previously stated where was shown that the distortion large rectangu- lar steel bar was reduced approxi- mately per cent when treating method was changed from carburizing flame hardening. Although very complete series experiments would required ac- curately evaluate the magnitude these forces, few elementary tests will indicate their general trend. rectangular blocks, one SAE 4145 steel and one chromium-molybde- num cast iron (type No. in. thick in. wide in. long, were heated 1575 deg. and quenched. The steel block expanded 0.0012 in. per in. length, and the cast iron sample expanded 0.0023 in. per in. length. This expansion was due the volume increase caused transform- ing pearlitic structure marten- sitic structure. illustrated the photomicro- graphs shown Fig. 17, 21, and 30, the structures produced the flame hardened case cast iron steel the types considered martensitic. Therefore, would reasonable 0 b p a ( \ assume that the volume change due flame hardening would tend cause equivalent amount expansion. the resisting forces due the hot upset- ting action are momentarily garded, and assumed that the specimens which the flame hardened surfaces are part are absolutely rigid and elongation takes place, the in- ternal stresses would 36,000 per sq. in. the 4145 specimen and 36,800 per sq. in. the cast iron These values are based the fact that the modulus elasticity steel million, and that cast iron million. Although more ex- haustive tests might prove that the above figures are quantitatively inac- curate, they least serve indicate the fact that there are very appreci- able unbalanced internal strains set any method hardening which produces martensitic layer one surface parts the general design However, previously stated, the forces due hot upsetting must considered before the actual internal stresses which exist flame hard- ened part can accurately evaluated. approximately evaluate the magni- tude these the in. surface bar SAE 1020 steel 134x2x12 in. was subjected the same flame treatment which would used flame harden the corresponding surface piece SAE 4145 steel. rectangular specimen 134x2x4 1/32 in. long was taken from the middle section the original bar. The ends were ground square and length 4.000 in. in. thick wafer was taken from the heated surface. The length shorter than that original in. block. That is, the flame treatment had produced upsetting action which would tend shorten the surface layer the metal, but this shortening had been resisted the greater strength the cold base metal. When the resisting forces this cold base metal were released cutting off the in. thick wafer the heated surface contracted 0.000125 0.000125. Although fully appreciated that 1020 steel not the most desir- able material for test such this, the results obtained clearly indicated that the magnitude the hot upset- ting action much less than that the expansion due the volume increase. rectangular test block 1/32 in. long was machined from in. block SAE 4145 steel which had been flame hardened ac- the four previous sections this highly informative report, the author described the characteristics three types iron, and the effect heat treatments the microstructure and hardness each material; data the flame hardening loyed, Cr-Ni and Cr-Mo cast iron the progressive meth- od; standardized operating conditions for hardening flat surfaces; procedure for hard- ening steel parts, large gears and long cylindrical parts. Herein, conclusion, atten- tion directed toward dis- tortion flame hardened parts, and the design and use special tips. cordance with the data tabulated the curve Fig. 20. The ends this specimen were ground length 4.000 in. and the soft base metal ma- chined off, leaving the in. hardened wafer. That is, the length this specimen checked with mi- crometers was 0.004 in. longer than the original test block. This was expansion 0.001 in. per in. length which took place when the forces ex- erted the base metal were released. That is, the internal stresses were 30,000 Ib. per sq. in. (modulus elas- ticity steel 30,000,000). These values are very close agreement with the previous results, which shown that the volume increase due the formation martensite caused ex- pansion in. per lineal inch, and the hot upsetting action caused contraction 0.000125 in. per lineal inch. That is, the basis these figures the actual expected expansion the flame hardened part would have been (0.0012 0.000125 in. 0.001075 in. per in. length). chromium-molybdenum (type No. alloy cast iron bar 2x3x24 in. was flame hardened the in. surface. 1/32 in. long section was taken from the central part this specimen, and the ends ground length 4.000 in. The soft base metal was machined off and the length the hardened wafer was found 4.004 in. long. That is, the wafer had ex- panded 0.001 in. per in. length. previously stated, the volume increase this type material due the forma- tion martensite was 0.0023 in. per in. length. This would indicate that the case cast iron the hot upset- ting was appreciably more than the case the steel specimen. That (0.0023 0.001 0.0013 in.), the difference between the expansion which occurred when in. wafer cast iron was furnace hardened and when in. wafer flame hardened cast iron was removed rigid block. That is, the hot upsetting had tended re- duce the length the surface layer 0.0013 per in. length, and the volume increase due the formation martensite has tended increase the length 0.0023 in. Hence the re- sultant expansion which occurred was 0.001 in. per in. length. The force required prevent this expansion, the internal forces the block, were 16,000 Ib. per sq. in. (modulus elasticity cast iron 16,000,000). can readily appreciated that parts having unbalanced internal forces this magnitude would tend dis- tort. part very rigid box type design, this distortion may not appreciable magnitude the time hardening, but some precaution- ary measures are not taken relieve balance these forces, there al- ways the possibility that further dis- tortion will take place when the part put service. study the effect stress reliev- ing flame hardened parts several rec- tangular specimens 1/32 in. were taken from the hardened surface in. long test block which had been flame hardened ac- cordance with the data tabulated the curve Fig. 20. The ends these specimens were ground length 4.000 in. Half them were stress relieved temperature 400 deg. for period hr. The soft base metal was then machined from all the samples and the lengths the hardened wafers were checked with micrometers. The average ex- pansion per inch length the stress relieved wafers was 0.0006 in., and the average expansion per inch length the wafers taken from the specimens which had not been stress relieved was 0.001 in. per in. length. That is, the stress relieving treatment reduced the internal stresses approxi- mately per cent. This definitely in- dicates the advisability re- lieving flame hardened parts wherever such treatment practical. However, will shown later, this statement must not misinterpreted mean that the distortion part reduced stress relieving because many instances it, will very greatly in- creased, this being especially true where long narrow parts are flame hardened one side only. The stress THE IRON AGE, November 1940—49 = a a, - i i i H { > and harden this surface only relieving treatment does definitely re- duce the internal strains, and this manner eliminates the hazard the part distorting after has been fin- ished and put service. brief analysis the distortion characteristics parts flame hardened production basis will clearly illus- trate the advantage balancing the stresses set this method heat range size from in. in. are regularly hard- ened four sides and the distortion very slight. Although these bars are stress relieved 400 deg. reduce the magnitude the internal forces, this treatment does not affect the dis- tortion. Accurately standardized hard- ening procedure produced balanced in- ternal stresses these parts, and the stress relieving treatment reduced them minimum. Although parts this type have been service for the past year under operating conditions which subjected them heavy intermittent loading, they have showed tendency distort. The part shown Fig. made chromium-molybdenum alloy cast iron (type No. and flame hardened under the conditions shown the above the hardened surface dis- torted approximately 0.010 in. concave. However, when the part was stress relieved temperature 375 deg. distorted additional 0.040 in. and the flame hardened surface was 0.050 in. concave. This definitely indicated that the internal stresses were very appreciable magnitude, and the part was not stress relieved would very likely distort when put service. order definitely establish the fact that the distortion was caused the lengthening the areas, one the parts was clamped heavy table such manner that the surface which had been 0.050 in. 50—THE IRON AGE, November 1940 ° ° ° part sign which internal strains will produce distortion. The stresses are less the flame hardened part than the car- burized part. ° ° ° concave was 0.0625 in. convex. was then placed large furnace and stress annealed 400 deg. for hr. This treatment did not appreciably change the shape the part. That is, the side which the flames were applied remained 0.050 in. concave. Although part this design flame hardened and stress annealed would not distort service, would very expensive grind 0.050 in. from the surfaces which had finished. avoid the necessity this excessive grinding stock, the internal stresses were balanced flame hardening the opposite side. When this procedure was followed the stress relieving treat- ment did not increase the distortion but only reduces the internal stresses which are present. These parts are regularly processed production basis, and the distortion rarely exceeds in. 0.010 in. second series tests part made the same material, namely chromium-molybdenum alloy cast iron (type No. 3), was conducted show the results clamping long slender piece bowed position during the flame hardening operation. The part long table and submerged water. The surfaces illustrated Fig. 33-B were flame hardened. This part distorted that the was 0.125 in. concave. second part 32—This chromium-molybdenum alloy cast iron part distorted about 0.010 in. concave when flame hardened. ; fi "7 ‘ Part took this shape Part was supported ateach loaded with 100 /b. weight shown and stress Flame hardened Fart was clamped this position and flame hardened the surfaces shown Part this shape flame hardening long slender piece bowed position during the flame hardening opera- 33—This series tests was conducted show the results clamping tion. the same design was clamped the position shown Fig. 33-C. That 34—These special tips is, the center was bowed convex 0.125 were developed for in., and the part was hardened. When flame hardening the clamps were released took the parts pro- position shown Fig. 33-D, that duction is, was 0.030 in. concave. was then placed draw furnace and loaded shown Fig. This allowed the stresses relieved, and the part took the form shown Fig. 33-F, that the distortion was equally bad that which occurred when was not clamped. The fact that the distortion this creased 0.115 in. when stress relieved under the conditions shown Fig. definitely indicated that had been finished without this lieving treatment would have all probability distorted service such extent that would have been use for machine tool part. view the fact that would abso- lutely impractical, not entirely im- possible, grind part this design d & — & a 4 remove 0.125 in. stock each side, was flame hardened the opposite side produce condition. These parts are regularly flame straightened hardening the opposite side. After this treatment the strain relieving operation does not cause any change shape and the average final distortion within the range 0.020 in. 0.025 in. The foregoing discussion definitely shows that parts the general design herewith considered must hardened such manner that the stresses are balanced and that definite advantage obtained they are stress relieved. Special Tips The use special design tips for parts run production basis fre- quently advantageous. The photograph shown Fig. illustrates few typi- cal examples. The tip “A” shown the above figure such design LEFT 35—This tip (Fig. 34) set small test specimen. THE IRON AGE, November xe by r fy Laer > ~ A | — = , x at: i | that the flame length very short, thus making suitable for such parts shown Fig. 32. may clearly observed Fig. 32, two surfaces are hardened simultaneously these thin tips which are designed produce short flame. This tip also used for hardening keyways and other parts which could not treated with standard commercial tip. The tip was previously discussed under the heading gear hardening. The design this tip must gov- erned the pitch the gear under consideration. However, neces- sary design the passages man- ner that will produce small flames uniform length and size. The small fin very helpful prevents the quenching medium with the flames. especially desir- able when the tip used for hardening internal gears, shown Fig. 27. The tips and are designed for hardening two surfaces simultaneously. Tips this type can only designed after extensive experimental work has been done with two separate units determine the exact location the Hames for the most satisfactory oper- ating condition. may noted that both are equipped with heavy fin between the flame holes and the water holes. This fin water cooled pre- vent its melting due the high tem- perature which present. The advan- tage such fin prevent the quenching medium with the flames. also provides very sharp background that the operator can more readily observe the surface being hardened. can ap- preciated that the set time for ad- justing tip this type much less than that required for setting two sep- arate tips. Fig. shows the tip set small test specimen. The water cooled circular tip designed for spot hardening for use flat surface which can spun rotated. The line drawing, Fig. 28, illustrates set-up harden small positive tooth clutch. The flame plate merely flat bronze disk which may turned and threaded long bar and any desired pattern holes can fabricated suit the part IRON AGE, November 1940 hardened. tip this type can used very extensively for spot face hardening parts the same general design illustrated Fig. 28. The unit shown designed operate Airco 4380 torch. The tip very simple design and can successfully used small commercial welding torch similar the Airco 9803. This tip not water cooled because its use not recom- mended for parts that would require sufficient amount heat necessitate that precaution. should only used for hardening small parts that require very few seconds heating time. There are many other types spe- cial tips which could designed for various hardening operations. How- ever, are expensive and should only used where standard commer- cial tips will not produce satisfactory hardening operation economically. Conclusion the foregoing discussion the writer has attempted point out some the problems that should consid- ered when cast iron steel parts are flame hardened. attempt was made prove that flame hardening properly applied will produce satisfactory mi- crostructures either cast iron steel. Definite recommendations were made outlining some the recom- mended operating conditions for both materials hardened the progressive method. However, the reader should carefully compare the data tabulated with his specific problem, and com- parison set conditions should made before following any these curves data. The writer would sug- gest the use least some test speci- mens sure that the recommended conditions because any operation involving many vari- ables are encountered flame hardening set-up requires very accu- rate procedure uniform high stand- ards are maintained. must remembered that any one all the following factors are variable and may cause unsatisfactory results. Variation the hole sizes due improper careless cleaning methods. (2) Any variation the rate lineal travel. Very unsatisfactory re- sults have been caused due unsteady motion produced vibration flimsy traveling mechanism. (3) The distance the tip above the a—The work must level with the carrying mechanism. b—Long slender parts will distort bow due expansion caused the heat, and certain cases this must corrected for during the flame hardening operation. (4) Level the water level, that the level the water sur- rounding the work, not usually vital importance, there are applications where slight vari- ation will seriously affect the re- sults. The set-up shown application where must accurately controlled. (5) Material very important that material used for flame harden- ing parts vital importance should purchased con- trolled specifications the most uniform results are ob- tained. may observed throughout this discussion all the operating condi- tions were based the use one type equipment. Unfortunately this data cannot applied some the other types equipment. This due the fact that there basic differ- ence design the mixers used the various manufacturers. Due this .condition operating data which would entirely satisfactory with the make torch considered this paper would not work all applied some the other equipment. Acknowledgements The writer wishes express his appreciation the following members the LeBlond Machine Tool Co. organization for their many con- structive criticisms and suggestions: William Groene, Davis, and Floyd Wile. Many helpful suggestions were also made Thompson, Air Reduction Sales Corp. and Greene, Carpenter Steel Co. "he Be. y ‘ IGHT hundred steel executives, stainless steel fabricators, job- bers, distributors, financiers and others interested the industry were guests the Rustless Iron Steel open house inspection new 000 addition. This plant the only manufacturing establishment the world which devoted exclusively The event marked the completion expansion program inaugurated the management 1935 and intended for long-range accomplishment which has been shortened meet the requirements four-fold increase market demand for the products. Many the visitors were guests officers the corporation dinner the Belvedere hotel that evening when they heard brief talks which further amplified the significance Rustless Capacity now more than 2!» Ib. for each the population. Concerning the completion this first phase development, Tuttle, president and chairman the board the corporation, said: “In the history Rustless lieve that see refutation the defeatist philosophy that frontiers remain America. Rather, highest standard living established anywhere the world.” Mr. Tuttle presided the dinner. talks were made Charles Hook, president the American Rolling Mill Co., and Mayor Jackson Baltimore. \ddresses were delivered Deventer, editor and president AGE magazine, who dis- the Rustless plant development they had seen during the day. They were told that the annual consumption stainless steel the United States cussed the past and future the stainless industry; and Young, International Service lieve that see true expression the limitless opportunity that before us, the spirit free enterprise that the last 100 has produced the News correspondent who recently won inter- THE world's only exclusive stainless steel plant, entirely rebuilt and its productivity increased four-fold more than 75,000 tons annual melting capacity, all within the last five years. Raw materials yards are shown lower right center. Chrome ore stored under the light colored roof lower center. Next above the new melt shop and above the new laboratories. the structure under three roof-levels through the center the picture housed the new 1800 ft. straight line production set-up. Ingots the left end and completely finished stainless steel bars and wire come out the shipping department the right end aboard trucks and railway : { | national attention with series ar- ticles exposing conditions China, which resulted his arrest and trial the Japanese. Mr. preted conditions the far east the light the present situation. $1,500,000 plant addition Rust- less 1937 increased ingot capacity from 20,000 40,000 tons This capacity was shortly found inadequate, and the current expansion recently completed has pacity 75,000 tons year. Opera- tions have been stepped the point where the number employees has increased the past two years from 450 more than 1400. The program just completed involved the demolition practically all former buildings make way for larger and more modern industrial structures, and the plant has been equipped with new machinery. This first chapter Rustless’ indus- trial growth has been written entirely within the last ten depression years. Visitors the open house inspection saw the evidence this development day-long series tours through the plant. They visited every depart- ment where they had opportunity see the Rustless process stainless steel manufacture operation. They saw the methods laboratory control insure standard quality. And they learned typical applications stainless steel practically every in- 54—THE IRON AGE, November 1940 dustry including aviation, automotive, railroad, screw machine, chemical, oil refinery, heating and ventilation, laun- dry, dairy, food, mining, beverage, tex- tile, paper, electrical, shipbuilding and numerous other industries requiring metal with unstainable properties, great strength and high degree resis- tance heat and corrosion. Rustless believed the first company the stainless steel industry adopt the same straight line system among the automotive makers. Each the products passes APPING one the five elec- tric furnaces the new Rust- less melt shop. Their aggregate melting capacity now 75,000 tons year. straight manufacture through its own separate channel plant op- eration, thus eliminating superfluous From ingot heating shipping de- partment bars and wire are produced within single 1800-ft. building. the Rustless straight line produc- tion system ingots first pass through rolling mill where they are converted into billets. After being conditioned they are hot rolled into bars and wire. These hot rolled products then are an- nealed and pickled according the specifications individual customers. Stock which cold finished conditioned and then cold drawn centerless ground. final rigid inspection the bars and wire are made ready for shipment. When the management initiated its long-range expansion program 1935 the corporation’s principal producing electric furnaces, 20-in. rolling mill and 5-stand, 9-in. bar and rod mill. that year the company had melt- ing capacity 20,000 tons ingots. Melting facilities were changed 1935 from the original three 6-ton — furnaces three tons each. Two 16-ton furnaces were added 1940 which increased the annual melt- ing capacity 75,000 tons, nearly four times the capacity five years ago and almost twice the capacity 1937. the and mills which the corporation had 1935 was added mill has been added 1940 produce billets, sheet bars and slabs, well 3-stand, mill and 7-stand, mill for the production bars coils. added the cold finish- ing department has more than doubled production, not including new cold roll mill for the production special bar and wire shapes meet present- day conditions and customer require- ments. Finished bar and wire capacity now about 1500 tons month, be- tween four and five times the capacity 1935. Other operations have been The Rustless method stainless steel manufacture employs melting and other processes covered patents applications for patents which have been developed the own chemical and metallurgical engi- neers. The exclusive melting processes permit the direct reduction from chrome ore the chromium which gives the stainless steel its principal inherent qualities. Rustless also has pioneered the development chrome ore produced from deposits the United States and has been the sole user domestic chromite for number years. The products are sold the form billets, bars and wire industrial users, jobbers, and distribu- tors and the form ingots, blooms, slabs, billets and sheet bars con- stock drawn through dies the cold finishing department. This operation provides close control size, improves physical properties and gives the surface the wire mirror-like finish. verting mills for further processing into sheets, strip and plates. Officers the Rustless Iron Steel Corp are: Tuttle, president and chairman the board directors; Sc