The Iron Age 1929-11-28: Vol 124 Iss 22

THE IRON New York, November 28, 1929 ESTABLISHED 1855 VOL, 124, No. 22. Pioneer Work Difficult Subject Undertaken Discover Best Alloy and Casting Method for Journal Boxes Carrying High Unit Loads CORSE* BOUT ten years ago throughout the period. The railway executives and final phases the program metal all bearings worthy the name the were completed the staff became acutely aware the loss weight, after they are run-in, the Bureau Standards and fact that the wide variations practically zero long lubrication the results published the specifications for bear- Consequently test methods search Paper No. 13, entitled ing metals were inimical were devised which indicated compara- “Wear and Mechanical Prop- the interests both groups. tive resistance copper-lead-tin alloys Railroad Bearing sure, some progress combined rolling and sliding friction Bronzes Different Tem- been made technical when run dry, and resistance repeated cieties specifications pounding. Whether chill cast bearing senior metallurgist, for bearing metals, but due better than sand cast one still Rosenberg, assistant metal lack definite reproducible open question; either method appears lurgist, LeC. Harbaugh, data (or for other reasons) individual consumers refused accept the recommenda- tions. cent lead. give suitable results when the analysis con- research associate, and The material presented here- with developed much The Chicago Bearing Co. had definite ideas concerning the manufacture and practical applications bearing bronzes, but there was neither sup- port nor disproval these views the literature the subject. There was, fact, little but theories and per- sonal opinions. Also, material found satisfactory one group users seemed fail the hands another. January, 1925, trunk line railroad considered the advisability replacing sand cast bearings with others cast metal molds, the belief that the latter were superior. But investigation showed little evidence which base predictions that the change would bene- ficial. Lack this information influenced the Chicago Bearing Metal Co. undertake the investigation herein summarized, and late 1925 the work was begun the Bureau Standards, under the research associate plan. Darby, chief metallurgist the company, was very active not only getting the work started but super- vision the project well. The Chicago Bearing Metal Co. supported the work until 1927, when its interests were merged with those the Magnus Co., and after that date Shoemaker, engi- neer tests the Magnus Co., lent his cooperation. The writer this article acted consulting metallurgist *Metallurgical engineer, Washington. greater length the research paper noted. There are present generally accepted methods test nor any well defined procedure which may followed attempting compare different bearing metals. Reli- able information based practical experience, and per- formance service the logical criterion. For various reasons difficult approximate service conditions laboratory tests, but the latter can more closely con- trolled and can, therefore, give fundamental information value. was recognized, also, that supplementary ser- vice tests would great value, but for fair comparisons the conditions service must resolved into essential components which can expressed terms fundamen- tal properties. The major object the tests was find out the impor- tant physical group copper-tin-lead alloys within (and some cases beyond) the limits chemical composition and constitution ordinarily applied industrially railroad journal boxes, and supply infor- nation that might ultimately permit logical revision specifications. Alloys Selected Two groups copper tin alloys were studied, i.e. alloy with copper-tin ratio 92.5 7.5 and lead varying from 0.25 per cent, and second group with copper-lead 1431 | | ratio and tin varying from trace per Each alloy was cast sand molds and metal molds and the mechanical and wearing properties studied dif- ferent temperatures. Alloys were cast into “sticks” about in. long in. diameter, and both chill cast and sand cast sticks were cast end and gated the bottom. This method was unsatisfactory, the sticks thus prepared were filled with tiny pockets. Next was tried the method melting, freezing and re-melting under glass. This gave satisfactory results for laboratory tests but was too slow for commercial pur- poses. The equipment employed the metallographic exami- nations, hardness, tensile and notched bar impact tests was typical that used this continent and abroad. Special equipment was constructed for repeated pounding tests and shown the figure. Amsler wear-testing ma- chine was also used the wear tests. The important features both these special test units are summarized the captions. Wear Under Sliding and Rolling Friction Two sets tests were first carried the presence oil group copper-tin alloys containing different proportions lead. the first set the specimens were subjected sliding friction under contact pressures within the range normally encountered railroad bearing ser- vice. the second set the alloys were subjected com- bined rolling and sliding friction under relatively high con- tact pressures, Disks made railroad axle steel were rotated against the specimens for selected number revolutions, and the wear determined loss weight. Repeated and con- secutive determinations were made with the same pair specimens (bronze and steel) until uniform rate was attained. When test this sort its early stages the amount and rate wear will vary widely, but after initial period the curves plotting wear against revolution and against work turned toward the horizontal axis. After this preliminary wearing-in period, the loss weight dropped very low values the presence lubricant, and appeared impracticable develop with any degree certainty differences between the alloys. Therefore, seemed necessary make wear tests without lubrication. These results appear consistent with the view that after initial period which the contact surfaces “wear-in,” good bearings will undergo little further wear long complete lubrication maintained. Dry Sliding Friction Ordinary Temperatures Wear tests under sliding friction without oil were attended difficulties even fairly low contact pressures. The temperature the bronze quickly raised and resulted marked flow the surface metal. Under such con- ditions was difficult determine how much wear and how much plastic deformation took place. Likewise, vari- ations the frictional and thermal properties the dif- ferent metals probably produced variations the tempera- tures reached, and direct comparisons the results did not seem justified. Such difficulties were minimized with the lower rate slip and the small area contact between the two disks tests under combined rolling and sliding friction. There was less heat developed given time, despite the rela- tively high unit contact pressures, and there was probably also better opportunity for dissipation the heat re- sulting from the frictional forces. Therefore, wear tests without lubricants described herein were made under com- bined rolling and sliding friction. The first tests were characterized erratic losses 1432—The Iron Age, November 28, 1929 weight; individual specimens did not show consistent rates wear consecutive tests, even after preliminary pe- riod. addition change the roughness the con- tact surfaces from the original ground finish, change color and what appeared coating film was frequently observed. Formation such coatings seemed related changes the wearing and fric- tional properties the metal. The compositions these films are not now known, but they are apparently two types. The first, comprising films which looked like cop- per oxide, was observed the copper-tin alloys which were low lead. These same films also occurred the high-lead bronzes, but they were not easy detect the latter alloys, due the more frequent formation second type coating, viz., black film which was either lead lead compound. Tests far made, including X-ray analysis, have failed reveal the exact nature these surface effects. However, appeared certain from the preliminary wear tests bronzes without lubricants, that film forma- tion played part the erratic results, and that some method eliminating controlling these films should provided consistently uniform results were ob- tained. Copper scrapers were used and minimized but did not eliminate film formation. Single Blow Impact Tests Single blow impact tests were made notched speci- mens with Izod impact machine. All except the low-lead alloys had very low impact resistance. Increase lead per cent caused progressive decrease the impact values all tempera- tures between room temperature and 600 deg. Fahr., the first few per cent lead having greater influence than corresponding variation the high-lead range. Increas- ing the tin about per cent increased the impact resistance, but with higher tin the impact values decreased somewhat. These effects lead and tin were more marked the sand cast than the chill cast bronzes, except that the low lead alloys the chill cast specimens showed higher impact values some temperatures. general the impact strength decreased slowly with rising temper- ature 350 deg. Fahr., and then dropped off rapidly. The finely disseminated small particles lead the chill cast bronzes probably produce greater weakness un- der impact than the large lead particles corresponding sand cast analysis, and may more than offset the benefits the finer grain structure the copper-tin constituents. Pounding with Repeated Blows Small cylindrical specimens were subjected repeated blows compression both atmospheric and elevated temperatures. The rate deformation some the bronzes decreased the pounding proceeded, due gradual work hardening. The initial high rate defor- mation increased with the lead content and decreased with the tin content. Sand cast bronzes usually showed higher initial rates deformation. was found that the deformation produced given number blows increased rapidly with lead content per cent, and but little beyond this. The rate defor- mation decreased slowly with increase tin content per cent and then rapidly from per cent tin. The effects described above were also observed the temper- atures 600 deg. Fahr., although the actual changes due variations composition and casting conditions were less than atmospheric temperatures. General Discussion one laboratory test itself gives enough informa- tion determine the suitability different bronzes for industrial applications. Comparison must still based broad knowledge the characteristics the different 7 7 7 7 bearings determined from varied tests and from service records. Variations chemical composition change the mechan- ical properties, sure, but within certain ranges the chemical composition less important than the casting conditions. With few excep- tions the chill cast bronzes wore faster these tests and had less resistance single blow impact notched specimen than the same analysis when sand cast, but were more re- sistant repeated pounding and static tension. There still room for con- siderable argument the rela- tive merits chill cast and sand cast bearing liners, and the casting method used should de- pend the service which the Specifications might well limited series relatively few compositions with liberal tolerances for the major com- ponents. The analysis chosen and the casting method will naturally depend the service. The wide variations present specifications for bearings destined for similar service, and the narrow composition tolerances specified many companies, are not always justified. Naturally, the effects impurities and other intentionally added components besides copper, tin and lead will have studied before any complete specifica- tion can drawn up. study heat treatment these alloys produce desirable properties also advisable. the bronzes investigated, those containing less QUIPMENT Used the Repeated Pound- ing Tests. Specimen anvil subjected repeated blows compression the falling weight Furnace used for tests elevated temperatures. the driv- ing mechanism and prevents auxiliary blows from rebound Tests were made with weight 7.15 falling through distance MSLER Wear Testing Machine. Surfaces and move the same direc- tion but different speeds with lateral oscil- lation produced cam and under contact pressures controlled spring Friction recorded the torque indicator tests with lubrication the oil supplied from reservoir all tests the total load between specimens was 37.5 the slip ft. per min.; (Below) than per cent tin had poor mechanical properties, wore badly and were apparently unsuited for bearing service except possibly for applications involving low loads. The Iron Age, November 28, 5 “| — per cent lead can meet wide range service condi- tions. These bronzes not wear fast low lead bronzes and the surface does not roughen rapidly when lubrication fails. Where mechanical strength essential desirable keep the lead content near the lower limit the range. For many purposes the bronzes containing per cent lead should interchangeable, since the changes mechanical and wearing properties with lead content are small. The results these tests lead grouping bronzes consistent with the American Society for Testing Mate- rials tentative specification B67-27T for journal bearings railroad rolling stock, according which the tin may vary from per cent and the lead from per cent. Hardened Copper for Electrical and Chemical Equipment SES and properties the hardened coppers known and “tempaloy” and their welding char- cteristic were described by W. R. Hibbard, technical department American Brass Co., Waterbury, Conn., aper read before the International Acetylene tion, Nov. Physical properties are summarized table. will noted that these cold rolled alloys strength equal better than medium carbon eels. Everdur possesses excellent welding characteristics when welded the oxy-acetylene process. isting and non-magnetic, and resists corrosion, particu- larly hydrochloric acid and chlorides. will not ason corrosion crack. Tempaloy was patented early 1928 Corson controlled the American Brass Co. Nickel and ilicon are present the proper proportions form nickel silicide; when heated 750 deg. above, the nickel silicide solid solution the copper. may then hot rolled forged. When this alloy quenched from above that temperature, ductile and may worked. The silicide precipitated from solid solu- tion when heated for few hours 450 deg. C., causing the alloy become hard and strong. Annealed tempaloy hardened increased strength the weld well the base metal. Generally speaking, best use welding rod the same composition the base metal, but everdur can used welding tempaloy. fused boric acid flux may used, but for best results add per cent sodium fluoride. backing bar usually necessary. The flame should slightly oxidizing concentrate the most heat upon the weld, and its length must governed the thickness the metal. The alloys containing silicon flow much freer than low carbon steel when using the oxy-acetylene torch, and film silica forms upon the surface the molten metal. These alloys are hot short, therefore cool the completed weld quickly possible the solid state. The con- centration heat over small area possible likewise desirable and is, also, advisable make the weld one pass. The electrical industry has found many applications for welded high copper alloys. end rings. Motor bars are welded Copper-manganese-silicon alloy non- magnetic and this property utilized for certain elec- trical equipment. barriers, panels and domes for circuit breakers and switch-gear, where the current volume too high permit the use ordinary steel, are now fabricated from everdur, and others where the current volume not great, satisfactory results are obtained welding everdur inserts ordinary steel break the magnetic circuit. Deoxidized copper and high copper alloys such ever- dur are used extensively the fabrication heaters, coolers, condensers, evaporators and many kinds chemi- cal and engineering apparatus. recent use has been the manufacture copper radiators for heating buildings, reducing space and weights. the general practice make the header sheet heavier gage steel than the copper tube and press into shape resist pressure before the holes are punched and reamed fit the tubes; the latter are then welded quickly possible with the minimum amount heat prevent warping. Composition and Physical Properties Soft and Hardened Copper ppe Ox ou to 0.04 \ ‘ Cadmiur Phosphoru Copper Remainder nate Strength, ll Cast 28,000 Forged oo, 000 Welded 15,000 D ty ry it. ce Fahr 1.98] de 1.083 Coefl t « linear expat per deg. O0.0000177 H t ductivity ] S per sq n pe! th <Ness pe deg, 10 (b) Depending upon the a mild steel has heat sunt of deoxidizer present onductivity of 0.117 in the 1434—The Iron Age, November 28, 1929 Deoxidized Remainder Tempaloy Copper-Silicon-Manganese Alloy Conner Ni kel- Copper Cast Wrought Silicon Alloy 0.0 to 0.15(a) 1.1 Oto O.50Ca) 3 to 0.10(a) Remainder 30,000 $5,000 10,000 35.000 55,000 Sa 000 130,000 120,000 15.000 $5,000 10,000 9 8.4 1,981 1,868 1,981 1.08: ] 20 1,083 of 177 M0018 0.8 0.2(b) 0.063 0.45 0.18 r used units can forged shape, welded with tempaloy rod, and 0 3.20 0 xidiz ae 4 Heat Treatments for Rifle Parts Definite Temperature for Rolling the Barrel—Carburizing and Parkerizing Practice Described—Methods Putting Color highly vital factor consider the adoption new rifle for Army use simplicity de- sign and manufacture that will minimize con- fusion and misunderstandings when contracts for its production are let out large number concerns. This holds true also for the kinds steel and various processes which they are heat treated. This policy simplification manufacture has been carried out the Springfield Arsenal, Springfield, Mass., where fine military rifles have been manufactured for more than century, and will doubt extended include any new arms that may accepted. While there are more than steel parts this model, only five different steels are used. Specifications for these, for all essential purposes, are the same the S.A.E. numbers 1020, 1120, 1095, 1350 and 2340, with slight vari- ations. For instance, the rifle steel close 1350 S.A.E. and this compares with the War Department specification follows: S.A.E War Dept Carbon, per cent 0.45 to { ) 0.45 to 0.5% Manganese ...... 0.90 to 1.20 1.00 to 1.30 Phosphorus, maximun 0.040 0.050 Sulphur, maximum F 0.050 0.050 barrels can made three ways: Forging, the plant the Winchester Repeating Arms Co.; ma- chining from round stock, done the Colt’s Patent Fire Arms Mfg. Co.; and rolling, which the the shops the Springfield Arsenal. After shearing piece in. long and 1.4 in. diameter from steel billet, heated 1500 deg. Fahr. and rolled pass- ing through grooves, all the same set rolls. The piece reduced and tapered slightly each groove and when passes through the last roughly barrel shape, in. long and ready for heat treating and machining. This rolling operation accom- plished single heat. Formerly the practice was roll from temperature 1200 deg. and cool lime without any further heat treatment, but the present prac- tice, recently introduced, produces much higher physical characteristics. *American Gas Association, New York Both rifles sl at top of page are of the semi-automatic type NEALEY With the old practice the following physical charac teristics were obtained: Tensile strength, 110,000 vield point, 75,000 elongation, per cent; reduction area, per cent. This mechanical working tem peratures below the critical partially hardened the steel, does heat treating. However, the maintenance cost the rolls was very high and later was found that work ing higher temperatures effected reduction roll maintenance which more than offset the added cost heat treating, and materially bettered the physical char- series tests was conducted which included rolling barrels temperatures from 1200 1500 deg. Fahr. and heat treating afterward, with the following results: R ly Faht I t Str gil t fA 79.5 112,466 1.8 per ce per l } 74,276 104,42 2 » per cent 7.1 ver cent 14 74 f 115,4* 13.6 per cent ‘ 96,77 12 per cent r ce Rolling the 1500-deg. temperature was adopted. soon the barrel out the rolls straightened drop hammer, the temperature then being about 1200 1250 deg. then normalized heating 1700 deg and allowing soak this heat for about hr., after which air cooled. This temperature gives the better machinability than did the 1600 1650 deg, for merly used. then soaked heat 1550 deg. for hour and quenched oil for hardness, after which drawn 1100 1200 deg. for period hr. and air cooled. The bolt, receiver, are made from 2340 steel. Formerly W.D. 1325 steel was used, but the 2340 S.A.E. was found give higher physical and better shat- tering properties. With this steel the flange the bolt, for instance, will not blow off, and the receiver, instead shattering into many flying pieces, simply open under too great pressure, thereby minimizing the dan- ger the user. Heat treating practice for this steel anneal The Iron Age, November 28, | o | 1550 deg. putting the parts into furnace, bringing them temperature, turning off the gas and allowing them cool the furnace. For hardening, salt bath used, the parts being heated 1425 1450 deg. Fahr. for min. and quenched oil. They are then drawn salt tempering bath 700 deg. for hr. and air cooled, which gives them Treating the Smaller Parts Sight parts, cocking pieces, trigger, sear, screws, etc., are made from carburizing steel S.A.E. 1020 and 1120. The sear the small part which releases the firing mech- anism when the trigger pulled. “hair trigger” produced filing off the top this piece, and certain users this. However, bad practice, for only very small amount filing necessary penetrate the case and leave the soft steel wear away quickly; then there nothing hold back the cocking piece firing pin. Many rifles are returned annually the Arsenal have the sear replaced, after such tampering. carburizing these parts, they are first packed pots with charred bone put into rotary carburizing min. and withdrawn and quenched oil. They are drawn 770 deg. Types Furnaces Used the heat treating department gas used, mixed with air for combustion mixing machine. Four brick furnaces are used interchangeably for several kinds heat-treating work. Each about ft. wide and ft. square, and heated with two gas burners front and two the rear, firing under the hearth (semi-muffle type). The doors are counterweighted and lifted pulleys. indicating pyrometer with four-point switch serves all four. There are two pot furnaces, each furnace containing two 10-in. pots holding salt, lead and niter baths for tempering, hardening and blueing. Each furnace built brick encased sheet steel and four gas burners fire each pot, two from the front and two from the rear. Tem- peratures are checked indicating pyrometer with four-point switch. There also small 6-in. cyanide salt pot which set brick and heated with two gas burners, Facing the above row five furnaces, and the ‘ Parkerizing Installation for Rifle Barrels and Other Parts machines and heated about 1450 1500 deg. Fahr. for varying periods, according the depth case de- sired, which 0.008 in. most cases. The cocking piece held higher heat for hr., having first required hr. bring this temperature after was put the furnace. This produces case 0.012 in. deep. then dumped into sieve, where the bone allowed fall through, and the work gradually dribbles into oil quench gravity. Besides producing the case, this treatment tends harden the core. The cocking piece then repacked bone and re- heated 1300 deg. and held this temperature for hr., after which again quenched oil. This second heating refines the grain structure the case and core and reduces the hardness and toughens the core. This last part the process necessary, for the firing pin rod assembled the cocking piece, which would crack were not toughened. The sear given the first half this treatment, but the latter part omitted. Springs, including the flat spring actuating the fol- lower, are S.A.E. 1095 steel. These are put into fur- naces 1450 deg. Fahr. and, they are small, and only tray are charged time, they are heated 1436—The Iron Age, November 28, 1929 oil, water and brine quench tanks form row between. Three the five furnaces are about 3-ft. cubes and are the semi-muffle type. They are used for hardening tools high-speed steel. indicating pyrometer with five- point switch part this equipment, well re- cording pyrometer for more particular work. Handling Reamers and High-Speed Steel Heat treatment long reamers done small, circular furnace made the Arsenal. This about ft. high and in. diameter, built brick, steel encased, and with 6-in. hole the center. heated with three gas burners spaced regular intervals vertically and firing tangentially against steel muffle, which holds the work. This muffle consists length steel pipe capped the lower end. unique unit for hardening small parts high-speed steel consists circular steel shell, brick lined, and divided into three chambers vertically. This unit, which sets legs, ft. high and ft. diameter and heated with single gas burner firing under the hearth. Between each chamber and the next refractory tile with the correct number and size holes permit the pas- sage upward just the required amount heat. Thus | Group Gas-Fired Rotary Carburizing Machines the temperature the first chamber 2200 2400 deg. Fahr., the second 1600 1700 deg., and the top one 900 1000 deg. Method Carburizing Carburizing accomplished another room, one end which are four rotary carburizing machines. These consist steel retort within steel shell ft. long and ft. diameter, through which gas burners fire. The retort, in. diameter, extends from both ends the shell about foot. rests four wheels, two front and two the rear, and rotated means chain and sprocket, which engages another sprocket wheel fitted over the rear end the retort. One motor drives all four machines, and one indicating pyrometer with four-point switch used regulate the temperatures. front are two steel quench tanks with overhead monorail and hoist with which handle the sieves and baskets. The steel parts and bone are discharged into long sieve, the bone dropping through while the work rolls gravity into the quench where drops into baskets for further handling. the other end the room are eight more machines, similar type, except that they are heated with long gas-pipe burner, located the bottom the combustion chamber, the flames impinging the retort. These are driven from single motor and are used for tempering and blueing blackening. They are served with two oil quenches and two indicating pyrometers with four-point switches. Coloring the Parts Desired Oil blackening carried out follows: The work charged into the retort with charred bone, heated 900 deg. Fahr. and cooled slowly 650 deg. The bone then removed, saturated mineral cylinder oil and returned the retort, and the whole charge held 650 deg. for hr. The work then removed and quenched oil, which gives black finish, which has twice the life blue finish. Another method used here heat the bone 1300 1500 deg. and quench oil. Niter blueing small parts accomplished two- pot furnace, the baths being carried 700 900 deg. Fahr. The baths are mixture nine parts sodium nitrate one part manganese dioxide. The work im- ~ > Rota:y Gas-Fired Furnaces Used for Tempering and for Blueing and Blacking. left the quench tank The Iron Age, 28, mersed for about min., and quenched cold water; any adhering niter then removed boiling water. There are many variations from the above practice. Indicating pyrometers serve every unit. Parkerizing Applies Several Parts Rifle separate barrels and other parts are Parkerized The parts are first cleaned remove dirt, oil and scale, soda wash and sulphuric acid pickle room, followed rinse being used. The work then placed circular cast iron grating, the barrel excepted, which and carries the booth revolves parts through sand under pressure forced them through series nozzles. The barrels are sand rubbed. All parts, including barrels, are then placed racks, handled racks, two tank, tion. The barrels are put in, hydrogen gas overhead monorail system, and the are placed the Parkerizing solu- stoppered both ends. When first given off. The work kept im- where mersed until this action stops, which occurs within hr. This solution kept just below the boiling point. The work then washed boiling water and dried cabinets. The surface the steel charged into in- soluble phosphate, highly resistant oxidation. Test Bars Vary with Size Castings New Standards ROLAND NEEDHAM* principally researches made under the auspices the British Cast Iron Research Association, new British engineering standards have been issued covering eces for gray iron castings. the past eared that the use and interpretation test coupons has een } I tory and < ial, becaus« everyone connected the design and production was aware that the me- properties varied appreciably with the thickness thi tion; nevertheless one size test bar did duty for everything from engine bed plate small bell rank. mad quite clear that the average ten- rength iron decreases the thicker the sec- rate cooling the mold profoundly af- the solidified metal. This particularly the inner metal. Consequently, there compara- wea spor encased harder shell Both tensile and transverse test-pieces are now graded section suit the material they are intended represent For tensile tests there are three standard di- ters represent distinct ranges casting thick- ness. Disparities are thus reduced within narrow limits. Three Thicknesses and Two Grades For tran rse test too, circular bar are now made rve for these three casting thickness Valu the bre loads are also tabulated rd, not only the nal diameters, but also with small casting variations therefr This just ought be, because bending stress varies inversely the diameter cubed. Because metal the casting tallize radially, this should favor the circular shape ther than rectangular bars for bending tests. Further- more, square corners are source weakness, since they end toward the formation always undesirable cleav- age planes. thus doubly appropriate that the test- iece should more nearly approximate the condition en- rced correct design: e., that liberal fillets and semi- rounded terminal contours provided. the new provisions for the tensile test are llows: %-in. turned the waist in. and this serves represent castings and lading diameter cast bar thick; 1.2-in. cast bar turned 0.798- in. waist diameter answer for casting thicknesses above and in., while for thicker pieces 2.2-in. cast bar turned waist diameter 1.785 in. points are minimum in. each apart. The tensile strengths for these three bars are 12, and gross tons per sq. nate in. respectively for material, and 10, and gross tons per sq. in. for grade cast iron. 1438—The Iron November 28, 1929 may appear somewhat contradictory machine the cast specimens smaller diameter. does sacrifice some the strongest material, but removes sur- face inequalities characteristic.of cast bar. Practical considerations enforce compromise, and the balance prob- ably gives close approximation the correct result. Values Specified for Round Transverse Test Bars Transverse test-pieces nominally in. diameter, in. long, span supports in. apart, are made for cast- ings and including in. thick; 1.2 in. and 2.2 in. diameter bars, 21-in. long for 18-in. spans, represent cast- above in. respec- pains have been taken tabulating central ections for the three thicknesses and for both grades iron, ings between in. and in., and ively. loads and for diametrical variations steps plus minus 0.05 in. illustrating the effect plus 0.10 in. grade in. diameter must and minus material, transverse bar 0.775 carry minimum 835 lb., whereas the load for bar 0.975 in. diameter reaches 1620 lb. Modulus rupture does not appear the specifica- tion, but useful relative value. the casting thickness are: 54,000, 50,900 and also decreases increases. The approved figures 13,000 per sq. in. grade iron; 43,900, 42,400 and 38,500 per sq. in. for grade iron corresponding the three sizes bar. The specification permits the use bars either cast latter, stipulated that the bars must poured the same time and from the same melt the castings they represent. eparately, the engineer may prefer. Reclaiming Axles with Surface Cracks Tests University Illinois directed Prof. Moore indicate that car axles which have developed fa- tigue cracks service may safely used after they are turned smaller size, and least 1/16 in. below the bottom the crack. the material removed only the apparent bottom the fatigue cracks, the tests show that not all the damaged metal removed. theoretical result interest contained the report (Bulletin 197, Engineering Experiment Station, Urbana, Ill.) that heat treated axles 0.45 carbon steel may have lower endurance limits, determined “Farmer” specimens, than others made 0.55 carbon steel, not heat treated after forging, even though the ultimate and im- pact strength the former are materially higher. Fur- thermore, tests using 0.3-in. diameter “Farmer” specimens give endurance limits about higher than those for specimens in. in. diameter. von all case grade *Engineer, design department, English Electric Co., Ltd Getting the Best Out Equipment Whether Add New Manufacturing Units Remodel Existing the Relative Investments JOSEPH considering ways and means obtaining creased output given product from existing works the question installation additional pro- ducing units similar existing units weighed against the possibility altering ex- isting equipment. The ad- steel the fact stands out that the industry has the past been very slow making those changes the design producing equipment that favor increased production proper quality. fact, for number years (some spoken having, com dition new units involves paratively, drifted. equipment usually involves money. those quarters which features uncertainty attempt has been successful the outcome; such Question: hat part the The drawback seems cedure being rule con- equipment what movement the that few operating men and sidered the light ex- material way toward few engineers been periment, but the more rapid production? trained the methods possibility less investment the research worker, and and less labor other Few operating men and few en- still fewer men the charges, which many cases gineers are trained research meth- earch field are inclined means the saving large ods; still fewer research men are practical. amounts the capital practical—an unusual type re- type man required. vestment and a marked in- |] quired to discover opportunities for | The principle ; involved in crease earnings from the improved operations. the study operation capital already and its equipment from the Often the successful accom- tandpoint contemplated plishment such alterations improvement are not com constitutes the point dif- plex. The question ference between very pros- asked simply what part drawbench; reducing the blowing perous concern and one that the equipment wha loses money its operations. movement the material i} | ae yrocess 1s Standstill the way toward more rapid There can doubt the problem any more com that any concern which stay business must make those changes equipment and methods demanded the progress competition. However, not always the concern having the newest plant that shows the largest earnings. The older concern which operating plant that has already paid for itself has that advantage over the one with the newly built plant. has, besides, the opportunity making inexpensive alterations, the light operating experi- ence, both old equipment and design additions. Such plant can outstrip the new plant earning power, may seen comparisons the earnings certain plants during the last two three years. reviewing some major operations the production *A graduate of Oberlin College, Mr. Miller the Lorain, Ohio, plant National Tube of Jones & Laughlin Steel Corporation, and with Eris Steel Co., Erie, Pa. His experience has unusu including inspection, testing and metal steel making and rolling and cold rollir l-dra\ g of steel. For time was superintendent open-hearth and Bessemer the South Side works plex the case large operation than the case very small operation. The risk involved, only, greater. Increasing Production Cold-Drawn Bars OME years ago the writer was called upon increase possible, the output shop producing range sizes cold-drawn bars, mostly rounds from in. in. diameter. The major operation, that drawing the bars through the die, was done two benches oper- ated high-pressure hydraulic power. The speed pulling was satisfactory compromise between the pr: duction and metallurgical requirements. Also, the ators were highly efficient. There were, however, two features that restrained unnecessarily, the production rate. One feature had with the ejection the drawn bars from the cradle the machine. Here two slow motions ejection mechanism were replaced one rapid motion. The other feature was the slow return the drawing head. minor change, the valve openings and connecting The Iron Age, November 28, 1929—1439 vorked in piping, accomplished fast return the drawing head the limits control its movements. Thus very slight changes involving minor expendi- tures, entirely within the range repair charges, these benches were made produce nearly per cent more bars the same good quality formerly, and the shop immediately responded per cent expansion its capacity without additional capital layout extension the floor space. Here said: cannot increase the drawing speed, due metallurgical limitations, but can increase the rapidity other movements pro- duction that have bearing the quality the product. Speeding Bessemer Blowing NOTHER instance which advantage was taken limiting condition operation that Bes- semer plant making 9-ton melts, the blowing time which the general run iron was min. The ladle- handling equipment was limited 9-ton melts and could perform properly down 8-min. intervals. Thus the limiting condition the production rate the plant was the time blowing. was decided increase the diameter the vessel and the number tuyeres, this way reducing the depth (and pressure) the charge and increasing the rate supplying air while blowing. favorable con- sideration the time making the alteration was the bad condition the shells, which required their replace- ment. moving the outboard stand far possible, was calculated that the vessel could enlarged diameter that would accommodate the necessary added air openings bring the blowing time down about min. The reduced depth the charge, was thought, would reduce the tendency spitting, and there were indications that the new operation would improve rather than interfere with the chances for making Bessemer steel good quality. The change was made contem- plated, resulting gain production rate good quality steel around per cent. example major operations that stands out illustrative this method study, although arrived slower degrees and less direct planning, the blast furnace with the large hearth. the operation reducing ore the feature limiting production any fur- nace the speed movement the stock down the shaft. blast furnaces ordinary design the stock moves more slowly than would required merely for proper reduction and metallurgical reactions. The enlarged hearth not only provides the receptacle for the increased output iron; also modifies the bosh angle facilitate more rapid movement the stock downward, which results increased activity the furnace, providing the same time more room for the introduction blast. Whether, some one had planned such change ten years ago, the owners would have had the courage try questionable. The reasoning would that time have been sound, with the possible uncertainty concerning the metallurgical features. This, course, would enough deter any action other than gradual transition toward the lines now adopted. this case the more radical change high-cost equipment involves con- siderable increase investment, which could not made the face any uncertainty, although study the extent uncertainty might have been made. these three examples have been outlined: First, simple mechanical problem involving small expenditure; second, more complicated problem introducing metal- lurgical considerations already somewhat well understood, and greater expenditure; third, problem involving not only extensive change major equipment but metal- lurgical features not previously studied the extent required for making reasonably sure prediction suc- cess. All these cases bring out the features essential the study production methods and equipment that have with quantity and costs. The call for greater productivity legitimately based, not only upon increasing number individuals, but upon the increasing needs and requirements, wants and desires each individual and the broadening his life. natural call, therefore, and not artificial fabricated state affairs. who uses best advantage the tools production that are already his hands profits thereby. two skylights now under construction the plant the Auto Specialties Mfg. Co., St. Joseph, Mich., are fabricated from 3/16-in. ingot iron angles, without the use putty solder. One skylight ft. wide and 220 ft. long and the other ft. wide and 220 ft. long, with five ven- Solderless, Puttyless Skylight, Built Angle Iron tilating units. Each unit operated with Dayton operators. The skylight, which was developed the Michigan Fireproof Skylight Co., Benton Har- bor, Mich., has been put the market take the place monitor-type construction for factories, foundries, laundries and garages. 1440—The Iron Age, November 28, 1929 German vs. American Steel Practice Differences Analyzed, with Reasons for Divergence— Germans Ahead Combustion; Americans Lead Mechanisms ESTEP* well known, the United States leads the world production steel and Germany has again be- come second. Most the steel made the United States used domestically, whereas large percentage made Germany exported. This has had certain in- fluence upon the processes developed and methods pursued the two countries, has also very materially the supply and cost raw materials. Another factor which has affected the methods and the equipment used the quantity and quality labor available and the wages which must paid. Germany the greater percentage ore used comes from foreign countries, while the United States the great bulk mined home. Coal plentiful and good quality Germany, but its price for metallurgical purposes higher than that used here for the purpose. [Coke plants, blast furnaces, steel making, soaking pits, blooming and heavy finishing mills, plate mills, mer- chant mills, rod mills, sheet mills, tin mills and tube mills were taken successively the author and the charac- teristics each, the two countries, briefly described. particular, pointed out the divergences and told the reasons for the differences noted. Following brief abstract some the outstanding Blast Furnaces the United States blast furnace shell, supported mantel and columns, carries the weight the top and superstructure, and incloses the brickwork. Germany the furnace lining usually built and held to- gether bands, and separate columns extend from the ground top the furnace carry the weight above. The United States leads number and percentage large furnaces. There are perhaps six furnaces here which have averaged over 1000 tons day for least one month and one furnace which averaged over 1000 tons day for all 1928. Because the comparatively high price coal, has always been essential that steel plant Germany operate the highest possible thermal efficiency. and when Germany uses individual blowing units each fur- nace, and when they size the raw materials, then, con- junction with the per cent sintered ore the burden, believed that Germany may again take the lead output per furnace. Steel Making Operations Germany about per cent the total steel made the Thomas process. The remainder made open-hearth furnaces, usually stationary, where practi- cally all the scrap made the plant melted. Thomas steel used for ordinary products, such rails, struc- turals, merchant material, rods and wire. Open-hearth *Chief engineer, Perin Marshall, New York. This abstract paper presented before the politan section, A.S.M.E., Nov. 12, and sponsored the Iron and Steel Division the society. steel used for seamless tubing, sheets, tin plate and other products where this grade better suited. the United States the percentage the total pro- duction steel ingots the Bessemer process has steadily decreased over the last years. 1900 about 65.5 per cent the total was made this process, but 1928 only 13.1 per cent, although the tonnage was almost the same. Because the predominance Thomas steel Ger- many, arrangement plant different from American plants has been possible. Thomas steel can poured and stripped very quickly, and for many products brought rolling temperature without fuel merely inclosing single ingot pit for about hr. Construction stationary open-hearth furnaces the two countries generally the same, but there are some points where they differ more less radically. United States furnaces are equipped with water-cooled doors, frames and ports insure the longest life and the minimum delay production. Water cooling not done German furnaces any marked extent. Many Ameri- ean furnaces are also built with sloping backwalls, which greatly increase furnace life and minimize delays. Germany checkers have been developed much higher degree efficiency heat transfer than com- mon here. They are building checkers large and extreme height, making possible preheat the air and gas very high temperature. This means aiso that the temperature the stack gases much less than here—so low that uncommon find waste-heat boiler recent open-hearth furnace Germany. Fuel consumption per ton ingots Germany generally considerably better. This partly due use mixture blast-furnace and coke-oven gas open- hearth furnaces, this having been developed high degree efficiency and reliability. Blooming and Heavy Finishing Mills INISHING rails, heavy and medium structural shapes, and some special shapes done Germany almost universally upon two-high reversing mills, con- sisting two three stands adjacent and usually line with the blooming mill. Finishing done from the original ingot heat. The blooming and finishing mills for this class product Germany are somewhat larger than those common use here. the United States mill roll rails structurals 24-in. beams arranged differently. Here cus- tomary bloom ingot, deliver the back side the mill, crop and send blooms proper lengths the finishing mill. some few installations two- high reversing rougher interposed between blooming and finishing mills. many American plants sections corresponding those which would rolled, Ger- many, direct from the ingot heat are reheated before rolling. practically certainty that, for the majority The Iron Age, November 28, | 4 products which can rolled direct from the original ingot heat, mills the two types were installed side side, given the same materials roll into the same fin- ished products, the American mill would produce greater tonnage given length time with less labor. The first cost the American installation would little any higher. Tube Mills Tube mills can classified three kinds: butt weld, lap weld and seamless. manufacture pipe the butt-weld process, the United States far ahead Ger- many tonnage and equipment. Germany has few butt- weld mills and all are antiquated design and operated inefficiently. the winter 1928-29 the first installa- tion butt-tube mill equivalent design, capacity, etc., those common use America was installed. Practically lap-weld pipe made Germany. manufacture tubes the seamless process Ger- many has always led the world. The United States has been backward adopting this process. Further Divergences Noted the more advanced nations, tackling metallurgical and other steel-making problems, will achieve results which are practically identical all fun- damental respects, according letter from Big- gert, Jr., vice-president and chief engineer United neering Foundry Co., Pittsburgh, which was read Stewart Marshall the conclusion Mr. Estep’s paper. There are essential differences between the plant lay- outs Germany and the United States, according letter from Freyn, president Freyn Engineering Corporation, Chicago. the United States the layout along simple lines, providing opportunities for expan- sion departments and providing also easy transpor- tation from one place another. European plants lack the benefit adequate conception general scheme and plans for future growth. This is, course, attribu- table largely the fact that many the plants are old, the United States there more flexibility re- gard the tonnage produced. drop per cent the output not nearly detrimental total costs the case Germany. the latter country, Mr. Freyn writes, diversity products must made given set mills. There has been much help recently through mergers, which have made possible specialize better. Furnace Man Has Control Over Coke Coke oven plants and blast furnace plants are not un- der common ownership Germany, except few in- stances. The coke made largely the mines, that the coke which hauled and not the coal. This con- dition gives the blast furnace man less control over the quality his coke. Germany Leads Combustion Mr. Estep’s paper might very briefly summarized saying that has accorded the United States the primacy mechanical features and Germany the lead combustion, according statement Sidney Koon, associate editor THE IRON AGE, New York, continuing the discuss