The Iron Age 1941-12-11: Vol 148 Iss 24

ada, will eral over Ot- eral itral bord ent, ense with ford for t to Wel- with its nark onal pro- Today, when production lines are racing against time, Fairbanks Scales are not only keeping pace, but actually speeding industrial processes. Weighing takes place while material motion; small parts and products are counted, and predetermined amounts are weighed and disbursed auto- matically. Costly human errors reading and recording weights are eliminated printed weight tickets. Fairbanks Weighing means lower production costs and faster, more efficient production line. Write Fairbanks, Morse Co., Department 138, 600 Michigan Ave., Chicago, Illinois today. gee “EC bios uy rt. wo nt. ost ne. been 4 x American dition the the grea production best materials shortest time; the record industry. industry been put test now. Never steel been important. The Wean Engincering pany giving full the fastest possible stecl. Wean being Duty meered, produced and delivered time ler for Tank, Armor manufacturers defense THE WEAN ENGINEERING CO., WARREN, OHIO SUBSIDIARY COMPANY The BRODEN CONSTRUCTION Co. Cleveland, Manufacturers Strip and Wire Mill Machinery Do ring duction DECEMBER 18, 1941 VOL. 148, NO. VAN DEVENTER President and Editor BAUR Vice-President and Manager ° ° ° Managing Editor, LIPPERT News Markets Editor, ROWAN Machine Editor, OLIVER Associate Editors JAMES Art Editor, WINTERS Editorial Assistants Washington Editor: MOFFETT Resident District Editors CAMPBELL HERMAN KLEIN Pittsburgh Chicago Cleveland Detroit CHARLES POST 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 Newark, Seattle ° ° ° DIX, Manager Reader Service ° ° ° Advertising Staff Emerson Findle Robert Union Bldg., Cleveland Herman, Chilton Bldg., Philadelphia Hottenstein, 1012 Otis Bldg., Chicago 100 East 42nd New York Peirce Lewis, 7310 Woodward Ave., Detroit Ober, East 42nd New York Don Harner, 1595 Pacific Avenue, Beach, Cal. Johnson, Market Research Mar. Hayes, Production Manager. Typography and Lavout. ° ° ° Member, Audit Bureau Circulations Member, Associated Business Papers Indexed the Industrial Arts Index. Pub lished every Thursday. United States and Possessions, Mexico, Cuba, and South America, Canada, $8.50: Foreign, $12.00 year. Single copy, cents. ° ° Owned and Published CHILTON COMPANY (Incorporated) Executive Editorial and Office Advertising Offices Chestnut and East 42nd St. Philadelphia, Pa. New York, OFFICERS AND DIRECTORS MUSSELMAN, President JOS. HILDRETH, Vice-President GEORGE GRIFFITHS Vice President EVERIT TERHUNE, Vice-President BAUR, Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE, THOMAS KANE, HARRY DUFFY CHARLES This Week in... Editorial Challenge Accepted Technical Articles Flame Treatment Improves Fatigue Strength Heat Treated 18-4-1 Steel Specification Plating Nitriding Tank Track Control Tool Shapes Hydrogen Determinations Features Assembly Line Steel Fatigue Cracks ........... News and Markets Government Awards September Iron and Steel Exports and Imports Machine Tool Activity Non-Ferrous Metals Scrap Markets Iron and Steel Scrap Prices Comparison Prices Finished Steel Prices Warehouse Prices Sales Possibilities Products Advertised Index Advertisers Copyright, 1941, by Chilton Company (ine.) rican thi ne; this put | | 3 steel, but deliver time. From the moment the Ryerson switchboard flashes your incoming call until the steel laid down your plant, corps helpful, intelligent employees well-trained the Ryerson “Immediate Steel” tradition are your service. The likeable young women the phone-order salesmen, dispatchers, crane opera- tors, skilled warehousemen who cut, shear and shape stock sizes fit your specifications, truck drivers all them are key people Ryerson —key people your service, when you need steel! “KEY When You Need Stee Ryerson’s function not only supply your Although the National Defense essential industries come are putting forth every effort serve all Industry the best our ability. Naturally, many sizes and certain products are out stock. However, for the most part you can depend Ryerson for immediate shipment wide range steel products. best service during this period heavy demand, orders are advisable. Stock List sent promptly request. Joseph Ryerson Chicago, St. Louis, Detroit, Cincinnati, Cleveland, Buffalo, Philadelphia, Boston, Jersey City. | \ A 4 \ 3) THE AGE DECEMBER 18, 1941 ° ° ESTABLISHED 1855 Challenge Accepted the newly opened battle arena the Pacific, Japan has won first round means foul blow. What else could have been expected? For months have heard and read the inevitability our conflict with the Nipponese Lillipu- tians. And also have heard and read many optimistic predictions the rapidity with which would, such event, make clean- up. Some these statements have come from people who ought know and they have varied, the time required our Navy thorough job, from ultra-optimistic “half day’s work,” one retired admiral put it, six months’ job more conservative Navy opinion. You remember what the Lilliputians did the giant Gulliver when they found him asleep. They knew very well indeed that they would not stand chance fight him under Marquis Queensbury rules, they jumped the gun the little men Nippon have taken our own estimate our prowess seriously, and assume they did, then their one hope success what they, too, considered inevitable conflict was what those other little men did. attempt tie the giant down before could make his mind act. They did just that. And should have expected something this sort and have been ready for it. But their initial success the first round will make difference the final outcome. The final outcome will decided United States continental soil and not the far flung reaches the Pacific. will decided the mines and the steel mills and the machine shops America, which can outproduce Japan one any needed mechanism war. Have dive bombers and heavy long range flying fortresses made the battleship obsolete? Then the productive forces America will breed these locusts destruction such swarms will darken the sky over the possessions the Emperor who calls himself the “Son Heaven.” Whatever may required win this war and destroy forever the insane ambitions the would-be dictators and imperialists, America will now produce. ships guns tanks planes, American factories will now work never before produce the means destroy these monsters. Forgetting our former petty differences, employers and employed will from now on, until the ultimate victory, work tirelessly and cheerfully side side toward the common goal preserving the freedom all men and women. This the solemn pledge that American industry gives America this crucial hour. re | | q | | | 4 | / ° ° | | | | | ® | | } | | | | } } } } Tin Plate Also Plays When Uncle Sam sets out provide food for American soldiers and sailors must the very best—not only when bought more important still, when the call for sounded. That why our Government purchas- ing vast stores wholesome food —the finest meats, tree-ripened fruit, garden- fresh vegetables—with their purity, taste and nutritive value safely preserved hermetically sealed tin cans. Inland tin plate—made from the highest quality steel, tightly coated with pure ZA gr" g Important Role Defense Program virgin tin—is being used regularly leading manufacturers who are pro- ducing many millions these cans for the needs our Army and Navy and, course, for the civilian population. Inland tin plate also widely used both the United States and abroad con- nection with our aid nations resisting Thus Inland tin plate takes its place with the many other Inland products now playing important roles America’s Defense No. Job. LL A B 4 7H | j | ‘ | made from forged solid bars, and this report gives the re- sults fatigue tests made tubu- lar axles having about one-third less weight. While these tests were made car axles the results may applied other problems wher- ever shafts are used. The press fit axle introduces severe stress concentration; and axle fa- tigue failures, when they occur, often develop the press fitted region. order improve the fatigue strength axles, the flame treat- ing process was applied the sur- face the wheel seat which region high localized stresses. This method gave more than per cent greater strength than axles the as-rolled condition. Quenched and tempered axles were inferior comparison with the as-rolled and flame hard- ened axles. Investigation was made internal stresses the tubular axles means explaining these results and correlation shown between the fatigue strength and residual stresses. This correspond- ence indicates that the flame hard- ened and as-rolled axles, which had the highest fatigue strength, also had residual compressive stresses the surface. the other hand, the quenched and tempered axles, car axles are usually Fatigue Strength Improved Flame Treatment —Lengthy theoretical discussions residual stresses appeared THE IRON AGE, Sept. and 25. Herein are data the practical utilization internal stresses, and also correlation such stresses with the fatigue strength tubular axles. shown that residual stresses can highly beneficial, rather than detrimental. having the low- fatigue strength, had residual tensile stresses the surface. The de- tails the re- search made this problem are graphs. TUBULAR AXLE DESIGN: photo- graph test axle and wheel as- sembly shown Fig. and the axle dimensions are outlined the line diagram Fig. and shape axles tested were identical the wheel seat and the body between the wheels axle which could used service under modern railroad car. The disk shown mounted the axle represents wheel and was pressed-on the axle accordance with usual mounting practice in- dicated Table II. this test the equivalent wheel was agreement with existing material specifications for multiple wear wrought steel wheels, and the scleroscope hard- ness measured the hub face the wheel. MATERIAL: All test axles were made from the same heat 1045 steel. Chemical analysis and physical properties samples from test axles are shown Table These tubular axles were rolled HORGER Head, Railway Engineering and Research, and BUCKWALTER Vice-President, Timken Roller Bearing Co., Canton Mannesman mill 734-in. outside diameter with wall thickness 15% in. interme- diate forging forming opera- tions were used. After heat treatment the axles were machined all over the outside diameter but the bore was not ma- chined. HEAT TREATMENT: These tubular axles were tested three condi- tions, follows: (a) hot rolled; (b) quenched and tempered, and flame hardened. The hot rolled tubes (a) were spaced apart and allowed cool still air cooling beds immediately after passing through the tube mill. Photomicrographs made the out- side and inside diameters such tubular axles are shown Fig. The tubes (b) are the same (a) except they were first nor- malized 1650 deg. F., reheated 1500 deg. and then quenched water for six min., during which time the tube was moved and down and endwise the water. Both ends the tubes were capped with sheet metal plates welded the tube intermittent points. These caps did not entirely prevent the entrance water inside the tube but did restrict the flow. Fol- THE IRON AGE, December 1941—47 : + 4 + \ ) + | > bi + 4 Se 4 ABOVE IG. tests made tubular axle assembly shown here. Note size contrast between usual fatigue test specimen workman's hand and full size axle. ° ° ° IG. 3—Longitudinal section IG. 4—Longitudinal section BELOW as-rolled tubular axle No. 372. quenched and tempered axle test axle as- 100 diameters. No. 375. 100 diameters. sembly. TEST AXLE ANDO WHEEL ASSEMBLY BOLTED TO ROTATING HEAD OF FATIGUE MACHINE AXLE FATIGUE FAILURE HER DEVELOPS HERE SECTION SPRING LOAD DETERMINE RESIDUAL APPLIED HERE WHEEL HUB DIA 48—THE IRON AGE, December 18, % / 16 ROLLED, WATER QUENCH TEMP. ROLLED ABOVE 240 Method axle. WALL THICKNESS DISTANCE FROM INCHES ABOVE 8—Hardness through cross-section axles with various treatments. LEFT | G . 6 — Longitudi- nal section flame hard- ened wheel seat. 100 BELOW diameters. IG. 7—Longitudinal section flame hardened wheel seat. 0.72 diameters. THE IRON AGE, December 18, 1941—49 260 | : q lowing the quench, the tubes were tempered 1050 deg. and al- lowed cool still air. Photomi- crographs made the outside and inside axle diameters are shown Fig. The tubes (c) are the same (a) except they were first nor- malized 1650 deg. and then only the wheel seats each axle were flame hardened. The method Fig. where the axle shown be- ing rotated lathe centers 110 r.p.m. field four equally spaced flame hardening heads. Heat- ing time varied from min., after which time the surface was water spray quenched and then drawn oil 350 deg. for one hr. Scleroscope surface hardness was before flame hardening and varied from after flame treatment. This surface was then ground for the wheel fit removing about 1/32 in. the diameter. photomicrograph taken through longitudinal section the flame hardened region shown Fig. and photomicro- graph given Fig. Results hardness explorations through longitudinal cross-section the tubular axles treated dif- ferent manners are shown Fig. METHOD TEST: These axles were tested large -ro- Wheel Mounting Conditions TABLE Chemical Composition and Physical Properties Physical Properties Chemical Water Quenched Composition Hot and Tempered: Carbon 0.50 Yield strength, per sq. in.’ 61,000 63,500 72,000 81,000 Manganese 0.73 Tensile strength, per sq. in. Phosphorus 0.017 Reduction area, per cent 41.9 42.2 47.2 50.6 Nickel 0.25 Elongation, per cent 22.0 23.0 20.5 21.5 Chromium 0.13 Brinell hardness (end tensile specimen) 183 192 217 223 Silicon 0.27 Tensile specimens taken from center wall thickness in. diameter in. gage length. Determined drop-of-beam method. tating cantilever beam fatigue ma- chines. The axle supported the test machine bolting the rim the wheel rotating head the fatigue machine, operating about 1500 r.p.m. constant spring load applied the opposite axle journal. This method loading, shown Fig. applied bending moment the axle the same shape that employed the de- signer when using combination vertical and lateral forces (Reuleaux Method) determine axle size. TABLE Results Fatigue Test Calculated Bending Hub Stress Inside Hub Face, Lb. Per Sq. In. Basis of: | No. Solid Axle Actual Wheel Fit Same Diameter In. In. In. Tonnage Tubular Tested | | As-Rolled Condition 373 0.0113 17,000 19,400 371 0.0115 110 13,500 15,300 374 0.0103 12,000 13,500 Water Quenched and Tempered Flame Hardened 381 0.0163 120 19,000 21,600 382 150 19,000 21,500 50—THE IRON AGE, December The stresses expressed this article refer the nominally calcu- lated axle beriding stresses the end the wheel fit, shown Fig. Here the bending moment equal PL, and this product divided the section modulus the axle obtain the bending stress. For convenience compari- sons made later, the bending stress expressed Table for the actual test axle tubular section and also the axle were solid section. Axle Life Remarks Axle Condition Wheel Fit Equivalent After Test Revolutions,| Miles Millions 1.07 1,910 broken 0.68 1,210 broken (Fig. 6.90 12,300 broken 18.01 32,100 test 0.40 708 4.87 broken 4.20 7,480 broken 99.6 175,500 not cracked 85.7 152,600 not cracked The safe design values endur- ance limits given Table III are based test least 84.3 million axle revolutions, which equivalent 150,000 miles 36-in. diameter wheels. DISCUSSION FATIGUE TESTs: Fatigue tests made these various axles gave the results shown Table All fatigue failures devel- oped from the outside diameter, not from the bore, and the axle wheel fit. typical axle failure shown Fig. Table III summarizes the allow- able fatigue strength values for the wheel seat portion the various stress for solid axle. Few, any, axles are present railroad ser- vice with wall section thin the ones reported these tests. For this reason convenient express the results these tubular axle tests form which permits comparison with existing solid axles. assume the axle forces produced service the same whether hollow solid axle used, then convenient state the stress for the hollow axle equivalent stress solid axle. This equivalent stress, for the en- durance limit values Table III, therefore, expresses comparison the load carrying capacity the tubular axles tested with solid axle the same outside diameter. should mentioned here that solid axles*, tested manner in. Journals,” Fourth Progress Report, Assn. Am. Railroads, Chicago, April 1940. similar the tubular axles, 0.50 per cent plain carbon steel the as-forged condition, gave endurance limit 12,000 Ib. per sq. in. This value the same the fatigue strength the as-rolled tubular axle stated Table III. The tubular axle weighs about one-third less than the solid. Since railroad car axle represents unsprung mass desirable reduce such duce impact stresses. would generally expected that the quenched and tempered tubes would offer greater fatigue resistance than the as-rolled axles from comparison the physical properties (Table I), hardness val- ues (Fig. 8), and microstructure (Figs. and 4). This expectation not accordance with the find- ings, but discussion this offered later. Sufficient tests were not made the quenched and tem- pered axles determine how much the endurance limit would drop be- low the 12,000 lb. per sq. in. value. Without the benefit these fa- tigue tests, may expected that the flame hardened axle supe- rior the other axles investigated. Sufficient tests were not made the flame hardened axles deter- mine how much the endurance limit would above the 22,000 per sq. in. shown Table III, but this value represents increase per cent over the as-rolled axles. Results fatigue tests, reported the literature, members hav- ing severe stress concentrations, equivalent press fit, have shown that two steels (or the same steel but differently heat treated), the TABLE Endurance Limit Values for Tubular Axles Endurance Limit Value Lb. Per Per Sq. (1) Flame hardened >22000 >183 (2) As-rolled 12000 100 (3) Quenched and tempered <12000 Equivalent stress for solid same diameter tubular tested. Ratio equivalent stress load carrying capacity tubular axle with solid axle same diameter. Fig. test axle broken off wheel fit. one having the higher hardness and physical properties will sometimes exhibit the lower fatigue strength. such tests often reported that the fatigue strength the higher tensile steel with the pres- ence high stress concentration approaches that the material having lower static properties. The reason for this usually ascribed the greater capacity low strength over the high strength materials for yielding and distrib- uting peak local stresses. This ex- planation fails account for the results obtained with these tubular axles and also the findings some other investigators with fatigue specimens having sizable stress con- centration. much neglected factor current knowledge fatigue, and one which substantial practical importance, the pres- ence residual stresses and their influence fatigue strength. was believed that analysis residual stresses these tubular axles may provide some correlation with the fatigue strength obtained, and such examination was made. RESIDUAL STRESSES: The wheel seat section was machined from one full size axle each the three types treatments, using wheel seat portions which had not been subjected fatigue test indi- cated Fig. These tubular sec- tions were used make determi- nation the residual stresses pres- ent, and measured approximately 79/16 in. outside diameter after grinding, 47/16 in. inside di- IRON AGE, December — 4 CHANGES OF LENGTH AS ROLLED CHANGES OF DIAMETER v 300 250 200 150 DEFORMATION IN HUNOREO THOUSANOTHS OF AWN INCH PER INCH OUTSIDE DIA. TUB 100 CROSS SECTION AREA OF HOLE IN PER CENT OF TOTAL AREA BASED ON OUTSIDE DIAMETER 100 Fig. tubular axles after successive boring-out operations. LONGITUDINAL STRESSES OUTSIDE DIA. TUBE TANGENTIAL STRESSES ORIGINAL BORE AS ROLLED RADIAL STRESSES ORIGINAL BORE CROSS SECTION AREA IN PER CENT OF TOTAL AREA BASED ON OUTSIDE DIAMETER Fig. stresses tubular axles. 52—THE IRON AGE, December 18, 1941 ameter after smooth turning suf- ficiently clean the bore, 79/16 in. long after Sachs’ boring-out was used would desirable use sections where the length was least three times the diameter, but this could not done using the axle design shown. Determination Residual Stresses Rods and Tubes,” Sachs, Zeitschrift fiir Vol. 19, 1927, 352-357. Metallurgy,” Sachs and Van Horn, American Society for Metals, Cleveland, 1940. wherein each cylinder sively bored out and the changes length and outside diameter meas- ured after removing per cent the cross-section area. small amount metal was removed each boring and series cuts was required between each stage minimize the influence heating and machining stresses. All meas- urements were made using Zeiss Optimeter, which permitted read- ing length and diameter dimensions directly 0.0001 in. and estimat- ing least 0.000025 in. The average six diameter measure- ments, maximum and minimum, made three different cross-sec- tions and the average length measurements made four equally spaced locations the wall thick- ness were determined after each series boring-out operations. The cylinders were allowed equilibrium temperature gage room where all measurements were made under constant temperature and humidity. conditions. The results the changes di- ameter and length for these cylin- ders after boring out successive layers from the inside each tube deformations the residual stresses throughout the cross-section, were shown Fig. 11. RESIDUAL STRESSES VS. FATIGUE STRENGTH: correlation shown Fig. between the residual stresses present the outside di- ameter the tubular axles (Fig. 11) with the fatigue values (Table will observed that the as-rolled and flame hardened axles have residual compression stresses the surface and exhibit higher fatigue values than the quenched and tempered axle, which have resi- QUENCH AND TEMPER ; FLAME HARDE NEO : 400 4 O > z z a QUENCH AND TEMPER FLAME HARDENED a! < | | < EXPRESSED FOR SECTION AXLE FATIGUE STRENGTH ROLLED TENSION RESIDUAL STRESSES AXLES COMPRE SSION WHEEL SEAT OUTSIDE DIAMETER TANGENTIAL LESS THAN GREATER THAN QUENCH AND TEMPER FLAME HARDENEO Fig. between fatigue strength and residual surface stresses. dual tensile stresses the surface. Somewhat similar findings re- garding residual stresses have been reported and Buchholtz* *“Effect Residual Stresses the Buchholtz, Mitt. a.d. Ver. Stahlwerke Akt., Dortmund, vol. No. Sept. 1933. smooth shafts various steels about in. diameter. The alternat- ing bending fatigue strength was per cent compressive stresses the boundary, compared with the same material annealed and having zero residual stresses. High com- pressive stresses the surface were obtained different heat treatments which produced little change the tensile properties the steel. When these boundary conditions steel were changed from zero resi- dual stress tensile stresses, then the fatigue strength was decreased values about per cent. These tubular axle tests not isolate the influence internal macrostresses from the variations microstructive and they affect the fatigue strength. The association shown between in- ternal stresses and fatigue strength are interesting. would appear that the proper utilization resi- dual stresses offers considerable possibilities. Further research necessary order obtain understanding and practical basis control which may exercised obtaining favorable stresses. Improvements Wire Making Technique George Prentiss Co., Holyoke, Mass., recently de- veloped wire-drawing bench using variable voltage Westinghouse mo- tors. Rheostats and mechanical con- nections used present methods wire drawing are eliminated. Once the proper field adjustments are made each motor, stated, they can simultaneously started speeds for threading and attain full running speeds simply raising the supply voltage. The motors are said maintain their speed ratios exactly that the tension the wire constant each side every die, resulting greater mechanical and operat- ing simplicity. said that breaks the wire occur less frequently and starts are smoother. interest wire cloth manu- facturers for screens, filters, sift- ers, etc., the new Quill Winder recently developed the Fidelity Machine Co., Philadelphia, for ac- speeds. The machine, equipped with easily regulated hydraulic con- trol, winds six packages one time with uniformly even lay and taper. The taper automatically gov- erned control buttons that re- verse and successively shorten the traverse the same operation, as- suring free-running wire from shuttles the weaving operation. clutch regulates the tension conform speed and pick-up, elim- inating wire breakage. THE IRON AGE, December Surface Structures and Chemistry Heat Treated preceding two sections this article dealt with gen- eral review the experimen- tal objectives and procedure; metal oxide zone; treating from smith forge; preheating; effect super- heating vs. atmosphere surface varbon; water quenching, slerein, attention first directed miscellaneous ments. The information given last week indicates that the heat treat- ment 18-4-1 high speed steel rather simple operation. How- » 2 54—THE IRON AGE, December there are certain exceptions the general rules, which the fol- lowing are examples: Sections which have blind holes present problem. study sev- eral sections which had blind holes invariably showed some areas decarburized while other areas showed carburization. more thorough study sections this type was made follows: Six speci- mens, in. round in. long with 0.5-in. hole, drilled longitudinally 2.5 in. deep, were treated atmos- (top)—Oil quenched from 2350 deg., drawn 1050 deg. Carbu- rized zone base blind hole. Fig. (bottom) Oil from 2350 1050 deg. Decarburiza- tion caused sur- face contact the material with the furnace hearth. Both 500 diameters. pheres 15.5, 9.8, and 4.8 per cent carbon monoxide; 0.5, 3.0 and 6.3 per cent oxygen. These samples were preheated per cent car- bon monoxide atmosphere 1550 deg. for min., followed superheating 2350 deg. for total time min. The examina- tion these specimens, regardless the furnace atmosphere, showed that the entrances the holes were badly decarburized, while the bot- toms were excessively carburized; fact, they carburized such extent that some eutectic was pres- ent. Fig. shows the microstructure the base one these holes. examination this photomicro- graph shows that the carburized area has four distinct fields: first, eutectic; second, untransformed austenite; third, formed austenite (which char- acterized needles); fourth, normal struc- ture. Several tests were holes slightly smaller and slightly larger than in. diameter. each instance, was found that both decarburization and carburiza- tion took place. Examination the structures from the entrances the bottoms the holes showed decarburization, neutral areas and highly carburized areas. The neu- tral areas were usually found mid- way between the entrances and the bottom the holes. Another condition which fre- quently encountered change surface carbon the face con- tact with the furnace hearth. When using atmospheres 12.0 per cent carbon monoxide under, for in- stance, the surface contact with the hearth was often decarburized. This condition was checked quite thoroughly with sections square in. long. When the test sections made close contact with the 3 q 18-4-1 Steel hearth stainless steel trays, de- carburization took place. However, the material was supported that the atmosphere had free cir- culation, this condition occur. does not necessarily fol- low that decarburization will take place the surface contact, but from the numerous have been made, the indications are that the closer the contact between the material and the hearth, the greater the possibility for decar- burization. Fig. shows decar- burization fractured cross- section the face which was contact with the hearth; Fig. shows the microstructure de- carburized area caused surface contact. When the atmospheres have relatively high percentage car- bon monoxide (13 per cent) and the material makes close con- tact with the hearth, excessive car- burization likely take place. Fig. shows the surfaces sev- eral tools which were treated per cent carbon monoxide atmos- phere, and which surfaces due extreme carburiza- tion. The surface tool which showed this condition was analyzed for surface carbon milling five steps 0.005 in. from the wrinkled face. The results these carbon analyses (in per cent) follow: 0.76; step 0.74; step 0.72. The condition carburization decarburization the surface contact with the hearth may minimized placing tools the furnace the surface which will have little service actual operation. Both conditions can eliminated having the atmos- move freely around the work. This can accomplished sup- porting the tools above the hearth suitable screens. supporting tools, extreme precaution must prevent warpage due the high temperatures employed treating this steel. Borax occasionally used cer- tain types treating protect the surfaces. This method treating Was investigated with specimen in. round in. long, which was per cent carbon monoxide tem- perature 1500 deg. for total time min. When preheated, the specimen was rolled anhy- drous borax, heated 2350 deg. SCHLEGEL Metallurgical Department Carpenter Steel Co. Reading, Pa. ° ° ° total time min., and oil quenched. The borax coating after treating was removed sand blasting. The portion the specimen where the borax accumulated during the superheating was highly carburized, while that portion from which borax had drained showed neither car- burization nor decarburization. Fig. shows structure where the borax had accumulated during the superheating period, and Fig. shows the structure from which the borax had drained. a : 44—Decarburization caused surface contact with hearth when oil quenched from 2350 deg. Excessive decarburization this type steel generally characterized very coarse grains. Twice actual size. 45—Wrinkled surfaces caused excessive carburization. This condi- tion may occur contact surface highly reducing atmospheres. Actual size. THE IRON AGE, December ° ° 5 > 4 * * y e 3t Ch Fig. illustrates the structure the carburized area after drawing 1050 deg. F., and was obtained the same sample Fig. was taken. difficult explain why specimen (Fig. 46) where the borax accumu- lated, while the area which the borax drained (Fig. 47) was neutral. The author the opin- ion that the scale which formed during the preheat contained car- bides, and when the borax coating was applied and the sample trans- ferred the high speed furnace, the borax drained toward the base the specimen, carrying with both scale and carbides. After the specimen had reached relatively high temperature, the carbides the scale came into contact with the surface, resulting carburiza- tion. * IRON AGE, December 18, 1941 Carbon blocks used the heat treating high speed steels develop atmospheres which protect the surfaces from ex- cessive scaling and prevent de- the surface treating under these conditions, specimen in. round in. long, was treated from carbon block having inside specimen was heated tempera- ture 2350 deg. for total time min., followed oil quench- ing. The analysis the surface carbon steps 0.005 in. the diameter follows: Step 1.09; step 0.78; step 0.70 per cent. The analysis the gas generated the carbon block was: Carbon dioxide—nil. IGS. structures section coated with borax during the superheat. Fig. quenched 2350 eg., draw; section where borax accumulated during the superheat pe- riod. Fig. Oil quenched 2350 deg. draw; section from which borax drained when being superheated. Fig. Fig. 47, after drawing 1050 deg. All 1000 diameters. Carbon monoxide—32 per cent. Fig. shows the structure this specimen oil quenched, and Fig. shows the structure quenched and drawn 1050 deg. for total time hr. Fig. interesting, since shows that some the retained austenite partially decomposed tempering martensitic needles. Salt Bath Heat Treating addition furnace treating, this type steel may also treat- from salt baths. The amount salt bath treating undoubtedly will increase the future due the fact that great deal less oxida- tion takes place during this treat- ment. addition, the development ceramic pots has materially re- duced the cost and the number failures pot life. secured two different types salt baths; the first, having borax- boric acid base; the second, ba- rium chloride base. The test tions were in. diameter in. long, and the temperatures were 2300 deg. and 2350 deg. The time heat the superheating salt ranged from min. general practice when employing salt baths preheat the tem- perature range 1500 deg. 1600 deg. F., followed superheating around 2350 deg. After tools are the superheat, they are quenched into third which usually operated the temperature range 1000 deg. 1200 deg. The carbon analysis the samples which were treated the borax-boric acid bath are given Table XV. When these samples were treated this type bath, they were preheated po- tassium chloride-sodium carbonate bath temperature 1600 deg. After reaching the superheating temperatures, they were quenched into third bath operated tem- perature 1150 deg. This quenching bath also consisted potassium ate. interesting observe that the material treated from this equipment showed carbu- rization, similar that which obtained furnace treating. The set which was treated barium chloride high (included Table XV) heated chloride base tem- perature 1500 deg. F., and was quenched from the high heat bath into quenching bath which was ‘ at- vill at- re- ec- in. ‘he m- ols th, the sis ted are ese po- ate eg. ing his on- rve his bu- the ath vas ath vas held temperature 1250 deg. This third bath contained some sodium cyanide which may explain the carburization which took place. Explanation Carburizing Action The subject surface chemistry indeed complicated, and, clos- ing, the following suggested ex- the author’s opinion that when fur- nace treating, there are primarily two chemical reactions operating one and the same time. The first consists scale formation strictly reaction. Throughout the work, regardless the furnace atmosphere, the tem- perature the length time the furnace, all sections showed scaled surface after quenching. The author believes that this oxidiza- tion rapid the early stages that does not materially affect change the composition the but merely attacks the iron parent metal. The carbides being soluble the scale, eventual- come into contact with the parent metal, which the austenitic condition, and, therefore, capable dissolving the carbides; con- sequently the carburization. other words, the carburization direct result scale. the writer’s opinion, this explains why the degree carburization some- what greater the neutral oxidizing found when reducing conditions are employed. This may explained the basis that the oxidizing at- mospheres produce scale faster rate and greater degree than would found with reducing at- mospheres. this carburization dependent upon scale formation, then the type scale exert definite influence. loose, porous, flaky scale will permit the scaling reaction continue for longer time than will tight,.impervious scale. The second reaction which takes generally conceded that decarbu- rization may caused carbon dioxide, oxygen, moisture, hydrogen (moist) and hydrocarbons under certain conditions. After certain amount scale formed, the first oxidizing reaction ma- terially slowed down, and when this occurs the decarburizing action be- comes effective. This may explanation for the rapid carburiza- tion for short times and the de- crease the amount carburiza- tion longer times; finally, decar- IGS. and Microstructures section treated from carbon block. Fig. quenched from 2350 deg. F., from carbon block, not drawn. Fig. (bot- quenched from 2350 deg. from carbon block, drawn 1050 deg. Both 1000 diam- eters. burization with still longer times. The same reason can used ex- plain why per cent carbon monoxide atmosphere decarburizes this steel 1900 deg. F., while the temperature raised, decar- burization disappears, until finally 2400 deg. there extreme car- burization. These conditions are related, the author’s opinion, the degree scaling, since the temperature increased, the rate scaling materially increases. TABLE The sections which were treated the borax-boric acid bath also indicate that the carburization related the absorption the carbides which were the surface the steel. known fact that this type bath had slight washing action and apparently when this washing action occurs, affects the parent metal and not the car- bides. These carbides eventually are absorbed the austenitic mat- rix, resulting carburization. Salt Bath Treating Borax-Boric Acid Bath, Carbon Step Down Tests Temperature, Time, Deg. Min. Cut Cut 2300 0.77 0.73 2300 0.85 0.78 2300 0.80 2350 0.81 0.75 2350 0.80 0.76 2350 0.81 0.79 Barium Chloride Base Bath, Carbon Step Down Tests Cut Cut Cut Cut 0.75 0.84 0.76 0.75 0.77 0.80 0.73 0.72 0.79 0.77 0.72 0.71 0.72 0.83 0.75 0.74 0.74 0.80 0.74 0.72 0.78 0.82 0.72 0.72 Sections in. round in. long. Surface carbon machined bars 0.73 per cent. Treatments: Borax-boric acid: Preheated dec. F., bath. Superheated, time heat indicated table. Quenched 1150 deg. F., bath. Barium chloride base bath: Preheated 1500 deg. F., chloride base batb. time heat indicated table. Quenched 1250 deg. F.. NaCN base bath. Cut 0.0C00 0.0025 in. off surface. 0.0050 in. off surface. Cut 0.0075 in. off surface. - nm THE IRON AGE, December 1941—57 | Summary Findings When heating this steel for hard- ening, some metal-oxide variably forms, regardless the method heating. When furnace treating, this zone can held cent carbon monoxide atmosphere. This does not carburize decarburize during the preheating when temperatures 1500 1600 deg. are used. This steel carburizes during the usual heat treating operations. The degree carburization related the type atmosphere. Unfor- tunately, the oxidizing atmospheres which produce the largest amounts carburization cannot used for the treating the majority tools made from this steel. This study also indicates that this type steel may held heat min. reducing atmos- pheres without causing decarburiza- tion. Carburization, after studying both preheating and water quench- ing, must take place during the superheating operation. The behavior the carburized area during tempering dependent upon the degree carburization, resulting structure which has austenite. Under normal heat treating conditions, the retained austenite found the carburized zone may decomposed into mar- tensite re-tempering. The two types salt baths em- ployed this work showed that steel will carburize when treated from these media. the author’s belief that the carburization found related scaling when furnace treating, the washing action the salt when salt baths are used. Welding Jig for Long Structures ELDING structural crane length section shovel booms from ft. long has been greatly facilitated the plant the Osgood Co., Marion, Ohio, through the use revolv- ing type welding jig. The position- er, which has been successful use for over months, was devised Harry Hibbett, general foreman the welding and structural shop the firm, which builder ABOVE 80-ft. dragline boom production the revolving type jig. This equipment assures perfect alinement the finished prod- uct and enables all welds made down-hand position. RIGHT basic jig, showing the center revolving section with rectangular opening. opening may also triangular circular cross-section. IRON AGE, December power excavating and material han- dling machinery. this device the crane structure supported both ends trun- nion attachments and the middle revolving fabricated support which has opening that may either round, rectangular trian- gular. This center section sup- ported three rollers, the topmost one which can screwed down hold the assembly any posi- tion. The end trunnion bearings This which are carried high pedestals welded plate construction permit expansion and contraction the structure during welding and the whole rig maintains alinement the work any position. welding one the structural booms, the pipe lacing with flatten- ends first tack welded place. Then the entire structure welded the center both directions, revolving the permit all downhand welding. This meth- strains during weld- ing and since ening quired later, major por- tion strength retained for working stresses. y 4 4 . | Of n has ned eat ned zed hat hen the remaining subject con- specification plating discussed the meth- ods employed check deposit thick- nesses determine whether the correct amount metal has actual- been deposited. There are nine methods determining the thick- nesses metal Microscope Magnet Measle Chord Drop test Micrometer Jet test Induction Spot test Chemical Strip The microscope method one the most accurate methods check- ing plate thickness, because the actual thickness through microscope with eye- piece that calibrated that the exact measurement can obtained. order accomplish this, sec- tion the object that has been plated cut perpendicular the deposit order get true thick- ness. After cutting, the article alloy, bakelite, some similar sub- stance, and polished The sample then placed under the microscope and brought into focus. the microscope equipped with micrometer eyepiece, very simple obtain direct reading the thickness the deposit. This good method use provided there are large amounts work thicknesses this method the fol- lowing equipment Microscope, light source, microm- eter eye piece, polishing papers, holders, and mountings. Also, bit practice essential obtaining good results. All parts being tested are destroyed this method. Specification Plating Nine methods checking deposit thickness, well tables various metals for estimating the time neces- sary produce given deposits various known current densities are shown this last article specification ° Head the Institute Electrochemistry and Metallurgy Brooklyn Polytechnic Institute Consultant, New York plating. ° ° The measle chord method de- pends upon filing curved surface until the base metal exposed and then measuring the length the file mark. the object mea- sured flat, precision grinding wheel used until the base metal reached and the length the grind mark measured. either case the thickness can obtained substituting the following formula: Thickness where; the length cut the radius the grinding wheel the object. can measured directly the case the grinding wheel and ‘an determined rather easily the other case simply measuring the factor, using small instrument measures the radius curvature curved surfaces. The diagrams Fig. will illustrate the method each case. This method requires precision wheel, file, magnify- ing glass, and spherometer, which are all inexpensive and easy handle, and the time necessary obtain thickness comparatively short. The object that used not destroyed, but the coating ruined. This can off. however, and the object refinished. The method not accurate the microscopic method, but will give results that are suitable for most electroplating departments. The micrometer method consists either obtaining the thickness several pieces before plating and then depositing the plate upon their surfaces and then checking them again for their thickness, or, first applying the plate and obtaining the thickness the micrometer and then stripping the deposit and rechecking the thickness. The first the reverse the second, and both depend upon the difference between two readings. This type easy apply, but the surface must flat nearly for the best results. This does not work well for very thin deposits, the error too great. Care must exer- cised when the deposit dissolved, lest the base metal attacked, and large error which will show too great thick- ness. This method inexpensive, only micrometer used and However, not too accuraté and does not work well all shapes. The work not destroyed this method. The induction method calcu- lating thickness was orig- THE IRON AGE, December | mit the the and ten- ace. ons, eth- sid- ains ince ght- iter, por- the for | | | - inally developed for the organic non-conductive coating, but can, however, calibrated indicate TABLE the thicknesses metallic coatings. Plate Plate This apparatus necessarily consists coil wire wound around (Nickel laminated steel core which all sides except one. The coil and galvanometer that enlarged amplifying system. The cur- Cadmium rent flowing through the coil Gold Brass eter and change the flow reg Tin Nickel istered immediately. The electri- cal circuit closed and the flow Silver current through can varied Brass \Brass magnetic flux, which can done Nickel very easily closing the steel core. Chromium die cast- Chromium This done bringing the open ings side the lamination near metal- Silver Cadmium lic body such steel. When such Silver body brought near, Gold TABLE Solution Metal Concen- Base Stripping Specific tration No. Metal Stripped Solution Gravity Conditions Chromium Hydrochloric Acid 1.19 deg. Nitric 1.42 185 deg. Cadmium. Hydrochloric Acid 1.19 deg. Tin. Hydrochloric Acid 1.19 Anode, emf. Nitric Acid...... 1.42 Copper...... Brass... Notused...... Hydrochloric Acid 1.19 Chromium Hydrochloric Acid 1.19 deg. Same No. 11.. Silver Brass....... Gold Same No. Lead Alloy.. Copper Lead Alloy.. Chromium Same No. Lead Alloy.. NaCN, oz. per gal. Anode, amp. per sq. ft. Copper Dissolve base metal solution caustic soda 100 gm. per which leaves deposit. Brass... Dissolve concentrated hydro- acid, and analyze for copper, which per cent coating. 60—THE IRON AGE, December covered with zinc, cadmium, etc., the coating insulates the base from the laminated core, turn affects the deflection the galvanometer. This deflec- tion depends upon the deposit. The drop test method uses standard solution which dropped the article tested the rate 120 drops per min. until the deposit dissolved the chemical action the solution and exposes the base metal. The time, seconds, required accom- plish this noted, each second be- ing equivalent 0.00001 in. de- posit thickness. This method was developed pri- marily for zinc and cadmium coat- ings steel, but undoubtedly will adapted other metals the future. The following are standard baths: Zinc: Ammonium nitrate Nitric acid, conc. Cadmium: Ammonium nitrate Hydrochloric acid, The drop method has the advan- tage being cheap install and operate. Its accuracy good enough for the average shop plat- ing zinc and cadmium, and the ob- ject not destroyed, and after test- ing can refinished. The method, mium deposited upon steel. The jet method, developed for the more resistant uses steady stream the solution in- stead drops. has been applied copper, nickel, bronze, cadmium and zine with good results. How- ever, not general use the present time. principle, con- sists steady stream impinging the plated surface instead successive drops, and coatings commercial thicknesses require one two min. for penetration. The accuracy the neighborhood per cent. Only the coating destroyed and the object can re- plated with very little trouble. The apparatus necessary consists 100 The orifice should ad- justed cc. water passes through sec. reservoir bottle connected that con- stant head liquid maintained all times that constant vol- ume will flow throughout the test. The surface tested must free grease and chromium. The former can removed scrub- bing with powdered magnesium | oxide damp cloth and then dry- ing with clean cloth. The chro- mium can dissolved immers- ing the object hydrochloric acid 1.16 specific gravity containing per cent antimonious oxide and operated room temperature. clamped about in. below the jet 45-deg. angle. The stream liquid and stop watch are started simultaneously and allowed pro- ceed for sec., and then the spot examined. This repeated without removing the last piece until penetration below the jet observed. The actual time required accomplish this compared the actual time necessary for the same solution penetrate the same coating 0.001 in. thick. Care must taken see that the test piece run the same temperature the standard piece. The solutions used depend upon the coating being tested. For nickel solution containing ferric chloride, cupric sulfate and acetic acid used, and deg. F., 0.0001 in. removed sec. Ferric chloride 13.33 oz. per gal. Cupric sulfate 33.44 per gal. Acetic acid Ferric chloride the principal solvent. The copper salt produces coppered spot some metals the point perforation after the flow has stopped, allowing excess solution flow away. The acetic acid prevents localized action pores anodic metals like steel. This solution can also used for copper deposits steel. This type test can used for zine and cadmium, and solution used similar that employed the drop test, except that less con- centrated due the more rapid attack these metals. All solu- tions are standardized determin- ing the time flow required perforate unit thickness deposit. The spot test finds adaptation the determination thin chro- mium deposits that are not thick enough determined with the microscope the chord method. The test consists placing drop concentrated acid upon the deposit chromium and timing the period gassing. deg. F., each second equiva- lent 0.000001 in. This method depends upon the chromium going into solution, and for this reason the surface the metal must clean and the active state. the metal either dirty the TABLE Electrochemical equivalent 0.0020436 Density 19.32 GOLD AU+ 45.51 .0020436 Weight 0.00254 6.4432 144 19