The Iron Age 1943-08-05: Vol 152 Iss 6

AUGUST 1943 watched, closely, the pilots. For the accurate functioning these “clocks” may depend the lives the bomber’s crew. This vital accuracy, turn, largely due one mechanism: Ball bearings! NEW DEPARTURE ball bearings, the tens millions, are used ships, tanks, planes, guns, trucks. They are being manufactured round-the-clock schedule, BALL BEARINGS 3186 NEW DEPARTURE DIVISION GENERAL MOTORS BRISTOL, CONNECTICUT 4 4 3 - ij | FOR ACTION! warship prepares for life lines, stanchions, furniture, mess kits Whiting Victory Cranes there unnecessary gear...only what needed for the job ahead. Crane refinements and extras lose their importance the face to- day’s huge war-winning task. speed production, Whiting making Victory Cranes simpler meth- ods...using time-saving processes and readily available materials. More important than ever are OVERHEAD CRANES nearly Offices Chicago, Cincinnati, Detroit, Los Angeles, New York, Philadelphia, Pittsburgh, and Agents other principal cities. Canadian Subsidiary: Whiting Corporation (Canada) Ltd., Toronto and Montreal durability and dependable service —which never are sacrificed Whiting Victory Cranes. Each crane all Whiting cranes have been nearly sixty years. Whiting ration, 15601 Lathrop ¥. THE IRON AGE, published every Thursday the CHILTON CO. (INC.). Entered second class matter November 1932, Post Office Philadelphia under act March 1879, ~ yearly North America and South America, Foreign $15. Vol. 152, No. VAN DEVENTER President and Editor BAUR Vice-President General Manager Editerial and Advertising Offices Johnson, Market Research Mgr. Baur, Typography and Layout. Regional Business Managers New York New York 42nd St. 100 East 42nd St. Pittsburgh 1016 Guardian Bidg. 428 Park Bidg. Philadelphia Chicago Chilton Bldg. 1134 Otis PEIRCE LEWIS WARREN Detroit Hartford Conn. RAYMOND KAY Los Angeles 2420 Cheremoya Ave. ° Owned and Published CHILTON COMPANY (Incorporated) Executive Offices Chestnut and 5éth Sts., 39, Pa., U.S.A. OFFICERS AND DIRECTORS JOS. HILDRETH Vice-President VAN DEVENTER Vice-President WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE THOMAS KANE ° ° ° Member, Audit Bureau Circulations rane Memper, Associated Business Papers the Industrial Arts Index. Pub- North America, South America and Possessions, $8; Foreign; $15 year. Copyright, 1943, Chilten Company fice Vol. 152, No. IRON AGE Editorial Principles for Post War Enterprise Technical Articles Dolomite Refractories—Part Weld Cracks Minimized Preheating Impression-Cast Chuck Jaws Shaved Gears for Aircraft Engines Plastics and Plasticity A.S.T.M. Examine War Time Material Features News Front Assembly Line Washington West Coast Fatigue Cracks Dear Editor News and Markets Lakes Ore Fleet Nears Full Regulation Developed for Contract Steel Industry Financial WPB Steel Division Personnel Charted Ordnance Citations Presented Ohioans Personals and Obituaries Machine Tool News Non-Ferrous Metals News and Non-Ferrous Metals Prices; Scrap Prices Iron and Steel Scrap News and Prices Comparison Prices Year Finished Iron and Steel Prices Steel and Warehouse Prices Stainless Steel, Tool Steel Prices Semi-Finished Iron and Steel Prices Pig Iron Prices Ore and Coke Ferroalloy Prices Index Advertisers August 1943 100 101 102 158 160 162 163 164 166 167 168 169 169 172 173 174 | q q SNAKE BIT DON’T SEE HOW GUY COULD BIG MODERN PLAN LIKE THIS/ COPR. 1943 NEA SERVICE, INC. THAT WAS THE DAY TALKED THE BOSS INTO BREAKERS.” Chip Control avoids dangers and delays caused long, hot, tough chips alloy steel. Chip Control yields short chips that are more marketable, bring better price, 44—THE IRON AGE, August 1943 ENOUGH THINK THAT BERRIES RIGHT ABOUT AND THERE WAS SNAKES TH’ BUSHES! JUST REASON! IT’S MODERN THAT ONLY FEW MONTHS AGO WAS PICKIN’ WILD x 4) MEMORY LANE 3-5 and provide means for speedy recovery alloys national scale. For proved method producing chips with Firthite Sintered-Carbide ting Tools, refer pages 41, 42, and the Firthite Users’ Handbook. Ask fof Handbook FE-101. ESTABLISHED 1855 VAN DEVENTER President and Editor BAUR Vice-President and General Manager DIX Reader Service Managing Editor....... LIPPERT News, Markets Editor...D. JAMES Technical Editor......... OLIVER ° ° Associate Editors MacDONALD BARMASEL BUTZNER Editorial Assistants SCHIEN WILLIAMS BUTTERS Regional News and Technical CAMPBELL Pittsburgh 428 Park Bidg. PHAIR Chicago Otis MOFFETT Washington National Press BROWNE Washington National Press LLOYD Cleveland 1016 Guardian BRAMS Detroit 7310 Woodward Ave. OSGOOD MURDOCK San Francisco 1355 St. Correspondents incinnati PENLEY k for! Buffalo FRAZAR Boston HUGH SHARP SANDERSON Teronto, Ont. RAYMOND KAY Los Angeles JOHN McCUNE Birmingham ROY EDMONDS Louis JAMES DOUGLAS Principles for Post War Enterprise OME people say that too soon talk about business after the war and that all our thinking should now devoted winning it. And that after won will time enough plan the shape things come. seems that this attitude overlooks the fact that one cannot shift suddenly from one train thought and conduct another with the same facility that one changes cars railroad junction. Our thinking about business after the war and the relations Gov- ernment and the public will require just much careful considera- tion and preparation and perhaps even more than did the war conduct. Certainly more people will directly involved. required six months preparation, ate told, put the North African campaign motion. probably required much time for the planning the Sicilian campaign. Yet neither case were there more than half million our armed forces involved the fronts. Business men, statesmen and thoughtful people all ranks cannot begin too soon think about these things. And the thinking should divorced from politics, class interest and other considerations which prevent the objective approach. There are four simple principles which, seems me, could used guides thinking about business tomorrow and America tomorrow. They are axiomatic and should help one discriminate between pro- posals, legislative otherwise, and policies whether they are desir- able undesirable. The first principle this: The wellbeing employers, labor and consumers dependent upon the establishment and maintenance national environment that will permit the maximum exercise indi- vidualism consistent with the rights all concerned. The second principle flows from the first. this: maximum ex- ercise individualism business, labor and the consumer can only exercised when there minimum government control and gov- ernment competition with private enterprise. The third principle flows from the first and second. is: There can only minimum government control and competition self- liquidating national economy which wages, dividends and taxes result from profits from private enterprise and not from progressive debt financing. The fourth and last principle flows from the previous three. is: economy financed the profits from private enterprise necessitates the greatest amount broadly distributed purchasing power. This can only had securing maximum output man and machine, maximum employment our employables and maximum efficiency management operation. Think over these four principles. They are not glamorous the four freedoms nor can they attractively illustrated posters. But want attain the four freedoms well several million others, not know better practical approach them. — Launching one America’s newest type, PCE convoy patrol craft. Dog” Takes the Water The Navy calls them “busy shepherd dogs the They are the new PCE, unlimited ocean service patrol strong, highly powered, and heavily armed for action against enemy U-Boats found lurking anywhere the seven seas. Sub-assembled sections, these patrol craft are now mass production the shipyards the Pullman-Standard Car Manufacturing Company Chicago. Inland rolling thou- sands tons plates for their construction. SHEETS STRIP PILING TIN PLATE RAILS BARS TRACK ACCESSORIES helping supply the enormous ton- nage plates required the Navy and the Merchant Marine, Inland exceed- ing all past production performance. Out- put steel above the practical rating our mills—new records often stand only few days before they are broken— the more than 14,000 Inland men are alert for steel—more steel —until the day Victory, when new dogs” need longer take the water. PLATES FLOOR PLATE REINFORCING BARS STRUCTURALS INLAND STEEL CO. Dearborn Street Chicago Sales Offices: Milwaukee Detroit St. Paul St. Kansas City Cincinnati New York 0.60 supe paci big has Ame eng Fly Hea ble pri Squ au’ News One the most closely guarded production secrets the war, here mentioned for the first time, the making heavy gun tubes out seamless tubing, with breech block upset one end. Output one production line alone over 6000 barrels month. Timken Roller Bearing Co. developed the technique. The entire 9600 series steels, and and 8442 all will soon killed off because limited usefulness. High silicon the 9400 series likewise has caused difficulties, and change 0.20 0.30 Si, 0.30 0.50 Cr, 0.60 Ni, unchanged, imminent. 9425 and 9545 will added fill gaps; analysis 9261 will changed 0.10 0.25 Cr; analysis 9262 will changed 0.25 0.40 Cr. Coal strikes July, sporadic and short duration, none the less accounted for steel ingot loss 80,000 100,000 tons that month. Steel bullets in. sq. are being heated forging temperature 2100 deg. 113 min.—in contrast usual hr. per in.—by high speed gas and air tion ceramic enclosures. The new method, now pilot plant stage four five mills, heats in. diameter in. copper billets 1500 deg. min., similar nickel bullets 1900 deg. min. Successive sinking spells stock market quotations indicate that for once the Allied war effort must progressing almost well blazoned the habitually optimistic newspapers. Armament schedules, particularly aircraft, are state turmoil, with many changes underway, inasmuch Allied military successes have jumped the war time— table ahead months. And: Particularly significant the imminent severe cutback the and bomber program, favor light attack bombers and strafing planes for pacing infantry assaults. Speaking heavy bombers, the Germans have not yet used any their Atlantic types, many which were seen test flights almost year ago. Perhaps big reserve being accumulated Hamburg couple American cities. The P-51 (Mustang) North American fighter being equipped with new Rolls Royce engine and will likely 1943's best fighter. Bell's Aircobra also being revamped take Rolls Royce engine. Very good though the liquid cooled Rolls Royce engine is, the American built type has not kept pace with the numerous improvements made the British Rolls. The American liquid cooled Allison has never fulfilled expectations. American air cooled engines, however, have peer. Don't expect see pictures today like those six months ago showing American Flying Fortresses and Liberators limping home with half their wings shot away. Heavier armor, more guns and ammunition and more bombs have all raised wing loadings high they won't stand much punishment. new concept physical chemistry, explaining how micropores separate ble phases, has been developed Selas Co.'s Scientific Equipment division. The principle and its newly worked out techniques promise, for example, automatic removal condensed water from compressed air lines, without moving parts, and continuous water removal from gasoline. Prototype shops for hand finishing aircraft components are sucking woman power the snootier London suburbs. The shops, usually ballrooms, art galleries, Squash courts, etc., have unlimited supply part time workers from the neighborhood. Chilean technicians touring American war plants hint that Chile another Latin American country very much interested establishing its own steel industry with government backing. Swift local annealing machines set between presses one possible answer automotive industry's expected post war demand, intensified plastic and plywood design influence, for still deeper drawing and forming sheet steel. ‘ t i q | a il > 1 ° ° ° CHESTERS Central Research Department, United Steel Ltd., Stocksbridge, England ° ° ° serious limitations have hin- dered, though not prevented, the development dolomite brick. They are the tendency calcined dolomite “perish” standing, that is, react with moisture the air form hydrate, the reaction proceed- ing much more slowly than with burned lime, but resulting simi- lar expansion and crumbling; and the tendency dicalcium silicate formed dicalcium silicate with per cent increase volume. This re- action results the formation extremely fine powder and usually described “dusting.” Dolomite, both brick and mono- lithic form, has played, and playing, most important part the steel plant, but the above limitations re- quire good deal more imagination and technique overcome than required when dealing with burned magnesite. Since both dusting and perishing (apart from fine grinding) led the formation extremely fine dust, the causes failure dolomite brick are often confusing. Thus the early days dolomite brick manufacture, the presence free lime the brick dead- was not uncommon and sometimes perishing due reaction with water the atmosphere, from leaky cooling pipe. the other hand, similar phenomenon, actual dusting, might result from the inversion dicalcium silicate brick which had not been completely stabilized. Fortu- nately X-ray examination provides ready means deciding between these types failure, and the appli- this weapon that much the progress the manufacture really stable products can attrib- uted. discussing dolomite products, further ambiguity usually creeps in: the term “stabilization” used cover three quite distinct procedures: (a) The coating calcined dolomite, for example, with pitch, reduce the rate which perishing occurs; (b) the conversion the lime silicate ferrite obviate hydration during 48—THE IRON AGE, August 1943 storage and use; and (c) the addition boric acid, phosphates other stabilizers prevent the inversion would better the term “stab- ilization” were applied only the last two procedures, which are gen- erally carried Brick made coating dolomite grains, say with bond, are usually referred stable” brick since they are far more stable than ordinary calcined dolomite, but contain considerable amounts free lime which eventually react with moisture the atmosphere. Such brick have been described “bottled” brick, the lime being un- combined but separated from the at- mosphere envelope glass. X-ray examination shows beyond doubt that much the raw dolomite used true compound having the formula MgCa dolomites rich- lime being simply mixtures this compound with calcite. When, however, this material the dioxide lost and the product Chesters steel plant refrac- tories, that have appeared Iron are: “All-Basic Open Hearth Fur- naces,” Aug. and 22, 1940. “Steel Plant Refractories,” Feb. and 13, 1941. “Basic Open Hearth Above Sill Plate May and 29, 1941. “Basic Open Hearth,” Aug. and 21, 1941. “Casting Pit Refractories,” Nov. and 27, 1941. “Electric Steel Plant Refrac- March and 12, 1942. “Acid Open Hearth Refracto- ries,’ May and June 1942. “Soaking Pit and Reheating Furnace Refractories,” July and 23, 1942. “Acid and Basic Bessemer Nov. and 12, 1942. and Semi-Silica Re- Jan. and 28, 1943. “Magnesite Refractories,” June and 10, 1943. simply mixture lime and mag- nesia. This proved the Debye Scherrer X-ray photograph which con- sists super-position the lines the two oxides together with few lines due traces impurity. might expected, the lime this mixture much more reactive than the magnesia, the perishing basic being due initially the hydra- tion the lime, not the magnesia. The properties magnesium oxide have been given the previous sec- tion. Those lime are similar but more “possessive.” Thus where basic heated contact with silica ferric oxide the lime which reacts Like magnesia, lime cubic mineral having specific gravity 3.08 3.30. Pure lime said have specific gravity 3.32 and refrac- tive index 1.83. Its unit cell has edge length 4.799 Binary Systems Fig. shows the outlines the system, which were worked out far back 1916 Rankin and Merwin. The phase diagram very simple. The most important observa- tion for the steel plant that mix- ture these two oxides has melt- ing point lower than about 4172 deg. basic therefore very refractory. The system has already been discussed the section dealing with silica (THE IRON AGE, and 28, 1948). From the standpoint dolomite brick, simply binary section the all important ternary system The system particu- larly important since dolomite, when used steel furnace, always con- fronted with iron oxide, either slag constituent vapor the furnace atmosphere. will seen from Fig. that ferrite and ferrite have melt- ing points about 2190 deg. and 2550 deg. respectively, and hence not surprising that iron oxide has considerable corrosive action even straight basic. There are two compounds normally formed, namely 2Cal solid pour colo: mite ligh and pos line lim pre tur th: sil eli and ferrite often found solid solution with Brownmillerite 1:1_ com- pound has very characteristic red color similar that Grecian chro- mite, which shows even brighter under crossed nicols than ordinary light. The 2:1 compound brown. The di- Systems The particular part the system (Fig. which major interest the manufacturer and user dolomite brick, field immediately either side the line joining MgO Com- positions having higher lime con- tent than those represented this line may contain free lime (assuming impurities present) while more siliceous mix- tures will contain least small amounts dicalcium silicate. this fact which makes the manufac- ture dolomite brick such pre- carious business. The ducer continually balancing his process knife edge and whether falls the left the right seen from the diagram that such mixtures are very refractory, but that absorption silica, such may occur for example with drip from silica roof, soon brings the melting point down open hearth furnace temperatures. also interest note that such stabilized dolomite clinkers the magnesia present the free state. interest because shows that ab- sorption alumina tricalcium silicate results rapid drop melting point. For this reason dangerous allow dolomite brick and fireclay brick remain contact for long periods the temperature all high, say over 2370 deg. also shows that the content alumina dolomite brick batches should kept low possible. will again seen that, even with Straight ‘basic’, alumina has marked steel plant refractories, the author, the first two arti- cles, describes various dolo- mite systems, raw materials, and production clinker. fluidifying action. The effect mag- nesia stiffening melts contain- ing approximately equal amounts lime and alumina has already been referred the section dealing with magnesia. Liquid ~ ~ interest shows that ternary compound lime, silica and ferric oxide likely formed dolomite mixtures. The system has not yet been worked out all fully. contains the compound Brown- millerite, which appears solid solution with dical- cium ferrite one the usual phases slagged dolomite brick and basic open hearth bottoms. red- dish brown color and often looks like glass. of the Ca0Q-A1.0;- liquid MgO Mol, per cent Fig. CaO-Mgo sy:tem (G.A. Rankin and Merwin). -Fe,03 Mol, per cent 2—The system (R.B. Sosman and Merwin). Note the low melt- ing points THE IRON AGE, August 1943—49 A q q ag- bye nes few tive but asic ave 5200 rac- 5000 | has the ked nix- deg. ling 2800 2500 icu 4 the seen 2100 relt- 2000 +Ca0> CaO-Fe,0; + Fe, and 1900 xide tion Cad two nely system which deals with cement has been worked out con- siderable detail Lea and Parker. The field interest the dolomite brick manufacturer and user how- ever still incomplete. What really needed the quinternary system con- taining the above oxides together with magnesia. will probably long while before this information avail- able and the meantime research workers are forced limit such com- plex studies small part this system. Raw Materials Dolomite, unlike magnesite, widely distributed throughout the earth’s crust and has recently become im- portant because can used most positions furnaces sub- stitute for magnesite. America the transport distances are great, and unstable dolomite not attractive where the raw material can mined and calcined within relatively short distance the steel plant. The British deposits occur both the carboniferous and Permian sys- tems and are found the North England, Nottinghamshire, Derby- shire, South Wales and the Forest Dean. These pure rocks consist interlocking mass dolomite crystals varying size from 0.02 0.5 mm. dia. some the coarser varieties the crystals are large plainly visible the 3—The system (J. Merwin). Solid solutions \ Cad 50—THE IRON AGE, August 1943 nN Cristobalite Periclase naked eye. Table gives typical an- alyses the British deposits used for the production basic. these, the Derbyshire material forms the basis for the production both stable and semi-stable dolomite brick. will seen that the content im- purities quite low and that the main the content that varies. These pure stones do, course, occur even the same but where the content quarries, Blackness fluxes all high the stone not employed refractory. addition variations chemi- cal analysis there are also consider- able variations the texture. Just silica may occur compact form like Welsh quartzite porous form like sandstone, dolomites similar analysis may vary immensely porosity. Whether this has any serious effect the structure the fired product has yet shown. Distance film 4—Photometer curves Debye-Scherrer X-ray photographs. top (A) shown unstable dolomite brick containing (B) shows dusted dolomite brick containing Stable dolo- mite brick consisting shown bottom (C). The production basic consists essentially carrying out the re- action 2CO:. this reaction stopped im- mediately the has been driven off, the product far too reactive and porous for use the steel The much higher temperature, about 3092 deg. F., when the porosity drops much lower figure (about per cent instead per cent), and material capable being stored for seve caut all func and with ston fluxe oper prod denc fired the addi uct, proc cont that prod ciun fore mar Rad port Lime several weeks without special pre- cautions obtained. Great Britain all the dolomite calcined either cupolas kilns. The fundamentally similar the kiln, but narrower relation its height and pressure blown. lined with tarred basic and charged intervals with alternate layers stone and coke about 5-in. size. The coke not only provides the heat the stone, but also supplies fluxes which aid the sintering process. Great skill required operation kilns and cupolas the product uniform. Any ten- dency the cupola slip channel one point and thus yield soft material can best overcome skillful withdrawal material the bottom. the United States dolomite often rotary kilns and addition, usually iron oxide, made increase the stability the prod- uct, and speed the sintering process. Thus one proprietary brand tain 5.4 per cent iron oxide, most which has been added, while others contain considerably more. This means that proportion the lime the product already combined cal- fore the material enters the steel fur- nace. The processes which occur dur- ing the calcination have been sum- marized Thomas, Hallimond and Radley their Geological Survey re- port. They point out that the first used for the Production stabil- ited dolomite Steam hydration index (Origin moved for each curve) ‘ ~'Serpentin Percentage acidic oxides 5—Relation between steam hydra- tion index and percentage acidic oxides for clinkers prepared from dolo- mite and various silicates (after Rait and Green). effect heating raw dolomite the expulsion carbon dioxide from the magnesium carbonate which yields mixture magnesium oxide and cal- cium carbonate (calcite). only later stage that the carbon dioxide the calcite driven off. After the material has been fired picked over either con- veyor belt before shovelling into truck. relatively easy pick out the soft fired fraction both appearance and density. This need not thrown away but only con- served for certain purposes, for ex- ample, the basis bessemer, where relatively soft fired dolomite pre- ferred. The ceramic literature the last years contains numerous sugges- tions how dolomite can sta- bilized the lime fraction removed altogether. Certain gested are almost fantastic; others although showing promise, fall short being commercially feasible. Perhaps the first really successful experiments work scale were made Great Britain when 1934 bricks consisting 75/25 mixture dolomite and sudanite (magnesite plus tale) were found give en- couraging results open hearth fur- naces. The properties brick made from these materials have been given Tyler and Rees (see bibliography Part Two this article). Although modern brick made with serpentine addition instead sudanite rock, and big improvements have been made the methods clinker production, grading, pressing, drying and firing, the general type and composition all the stabilized dolo- mite brick now use Great Britain are essentially similar those made 1934. This first brick was made q not mi- er- ust rm ous ely "4 3 4 3 ° ° . iW THE IRON AGE August firing clots suitable composition, followed re-grinding, pressing small hydraulic press and firing baby kiln. They showed serious brick brick variation and periodi- cally suffered from hydration stor- age dusting service. February, 1936, Dr. Jay the Central Research Department (United Steel Companies, Ltd.) collaboration with Sir Lawrence Bragg, F.R.S., then Manchester University, showed that the bricks which hydrated amounts uncombined lime owing insufficient silica content in- adequate firing, while those which dusted (like electric furnace white Table Selected Analyses Raw Dolomite (Geological Survey Report, Great Britain, Vol. Residue. 0.34 0.47 0.20 0.05 0.78 0.76 1.37 2.22 0.65 0.01 0.38 0.12 0.02 FeO.. 0.39 0.42 0.17 0.08 1.19 0.05 0.04 0.04 0.04 0.03 20.83 21.02 19.72 20.35 18.54 221 deg. 0.03 0.05 0.04 0.11 0.10 H.O above 221 deg. 0.26 0.22 0.82 0.58 0.47 0.99 0.17 nt. fd. 0.23 0.01 0.04 0.04 0.03 0.07 45.84 45.75 46.63 46.01 Table Comparison Calculated and Determined Free Lime Contents (Rait and Green) Composition Mix Percentage Free Lime Percentage Dolomite Percentage Stabilizer Calculated Determined 100 29.64 28.40 flint 8.36 8.26 steatite 15.64 16.46 steatite 4.04 4.39 olivine 8.89 8.18 olivine 5.03 5.09 serpentine 18.60 19.16 serpentine 14.37 14.65 serpentine 8.15 7.00 serpentine 0.0 0.0 Table Range Over Five Years, 1933-1938 Source 52—THE IRON AGE, August 1943 falling slag) after use the open hearth contained considerable amounts silicate (see Fig. 4). This work emphasized the necessity adjusting the chemical composi- tion that all the lime was com- bined, but unstable dicalcium sili- cate was present. was therefore decided that the composition should such that the principal constituents the clinker were tricalcium silicate and magnesia, the reactions involved being essentially follows: dolomite serpentine composition which means that the brick contains small amount dicalcium silicate. Since this might otherwise invert, small proportion one more the known stabili- zers added the batch. More recently this subject has re- ceived thorough study Rait and co-workers and also Gilbert Seil and his staff. Both these groups have made systematic studies the progress stabilization starting with raw dolomite lime and adding in- creasing amounts such materials serpentine, olivine, zirconia, typical set re- sults obtained Rait and Green are given Fig. and Table II. Thus with the serpentine was found that iron oxide, per cent must added before the slightly the silica rich side this q free lime content (both calculated and actual) fell zero. very useful contribution the subject has been made Seil and his staff the preparation bibliography contain- ing brief abstracts all the prin- cipal work the orthosilicates the alkaline earths. actual practice the materials are first wet ground tube mill and passed slurry tank where they are kept stirred until fed into the top rotary kiln (Fig. 6). The firing zone the kiln was originally lined with magnesite brick dolomite-magnesite brick has recently been used with marked success. The kiln fired with pulverized coal and 2912 deg. the slurry passes through the kiln first loses water, then carbon dioxide from the mite. From then reactions occur which eventually lead the forma- tion silicate and mag- nesia, together with some glass and traces other minerals. the tem- perature the firing zone ticularly high, the pea size particles tend grow and may even yield balls clinker several inches diam ing prod the steel have tions has coun elem cons per such trol stud truc any the gine that heat fact ity 0.35 beec the crea pres simi this loyi har min forr open posi- com- sili- icate olved erate this the night abili- Rait ilbert roups the in- erials oxide, re- are Thus that the and iseful been the prin- the are and they top firing lined pecial cently The and passes water, dolo- occur and tem- rticles yield diameter. The red hot material leav- ing the bottom the kiln passes ‘hrough cooler and thence via ele- the crushers. The crushed product mechanically sieved, and the sieved fractions are stored steel hoppers. Other stabilizers have been em- ployed, for example iron oxide, but have not achieved any great commer- cial due various limita- tions. Thus with iron oxide the clinker has relatively low softening range. Properties vast amount work has been done the properties basic since the war began, but the present ac- count will limited the more elementary aspects the problem. Basic, delivered, varies considerably bulk density. Thus individual lumps may have density low 1.8 high 3.0 grams per typical figure about 2.6 2.8. obvious that where such wide variations exist quality con- trol can set only after careful studies have been made the vari- ations both within truck and from truck truck. The analysis the material from any given source fairly constant, the data Table III typical. The main variation the loss Weld Cracks Minimized COMMON misconception among welding fabricators that plain carbon steels can satisfac- torily welded under any and all con- ditions without preheat. Welding en- gineers have learned from experience that this not true, and that pre- heating all-important insurance factor cracks are avoided. Plain carbon steels welding qual- ity are defined containing 0.35 per cent carbon. The higher the carbon content the harder the steel becomes the weld and the heat- affected zone. This obviously lessens the ability deform and creases the danger cracking. The presence manganese also exerts similar hardening influence, being roughly 1/7 potent carbon this respect. Frequently, also, plain carbon steel contains accidental al- loying elements which increase its hardening tendencies. When welding, must borne mind that the more rapid the rate cooling, the greater the risk crack formation. Some the factors that ignition which tends higher with soft fired material due rapid hydration after calcination. The factors controlling hydration have been the subject great deal work. obvious that grain size, moisture content the atmosphere, and time will all have marked effect. Over long period the mag- nesia the basic would also hydrate but the initial cause perishing the hydration the lime phase. this connection should em- phasized that fineness basic does not necessarily mean hydrated mate- rial. Certain types crushers used the production fettling material may, either accidentally inten- tionally, produce considerable amounts dust, but provided this fettling used before becomes seriously hy- drated, its properties may even better than those uniformly sized material. X-ray examination offers far the best method studying the con- stitution clinker, but where desired demonstrate the presence absence small amounts free lime (less than per cent), other tests, notably White’s test and the glycerol test, are preferred. White’s test small amount finely ground sample placed glass slide and wet with solution consisting five favor rapid cooling and therefore in- crease the danger cracking are: rapid rate welding, small elec- trode diameter, small welding area relatively large mass adjacent HOTOMICROGRAPH 25X showing microcracks developed plain carbon steel (0.20 and 0.65 per cent Mn) after welding without preheat. When the same material was preheated with gas torch 200 deg. F., homogeneous weld structure was obtained, free from cracks. grams phenol dissolved c.c. nitro-benzene with the addition two drops water. The slide then examined between crossed nicols using magnification about 150. The presence free lime shown the formation long, highly birefringent needles which radiate from the free lime particles. Where the lime con- tent high these crystals appear al- most immediately and where low may necessary leave the slide for hour after preparation. Details the method used carry- ing out the glycerol test have been fully described Bakewell and Research Special Report (No.17). Table shows, there close corre- lation between the amount free lime expected from equilibrium con- siderations and that actually deter- mined the glycerol test. Like basic, stabilized clinker can vary appreciably bulk density, and generally considered that average figure least 2.4 grams c.c. should obtained for clinker the type here described. Note: Next week the author concludes this study with description the manufacture and properties dolomite and com- posite dolomite brick and dis- cussion applications. Preheating metal and low .atmospheric temper- ature. Preheating therefore highly desirable all times means minimizing these adverse factors; and cold weather preheating be- comes imperative precaution welding all steels. The photomicrograph the presence fine microcracks which occurred welding two sec- tions carbon steel thick with in. electrodes. When the same plain carbon steel was preheated 200 deg. F., homogeneous structure was obtained, free from microscopic cracks. Preheating was accomplished means gas torch. The tempera- ture was controlled making crayon-mark the plate with Tempilstik 200. When the surface temperature reached 200 deg. the crayon-mark melted liquid smear. Heating was then discontinued and welding was begun. When the Tem- pilstik (signaling that the temperature had dropped be- low 200 deg.) more heat was applied. THE IRON AGE, August 4 | a | q 4 { | | q 7 3 Ex if Impression- Push fit adapter Bushing TOP impression-cast mold used the manu- facture Kirksite chuck jaws for holding small forgings for aircraft tubing fittings. The machined end sample forging inserted the adaptor bushing and the low ing point metal cast about it. Pouring through the conical mold cap. ° ABOVE IG. 2—Details pair jaws for attachment two- jar air chuck. The workpiece cavity not shown. would correspond the particular forging held. ° RIGHT 3—Turning and facing one end T-connection forging which will used form the work cavity impression-cast mold. The o.d. must fit the adaptor bushing, Fig. The face scribed with line parallel the other the 54—THE IRON AGE, August 1943 ast AST metal chuck jaws hold odd-shaped parts for machin- ing operations have been some time other most shops. Usually they are made brass, bronze cast iron and generally certain amount cavity finishing with highly skilled labor necessary make them usable. Users jaws cast lead, babbitt fusible alloy have found them limited for high production because the lack durability. Over long period time, Amer- ican Screw Products the manufac- ture forged hydraulic fittings, fol- lowed the common practice machin- ing the jaws out steel. The pro- cedure was naturally slow, expensive and efficient only with skilled labor. effort comply with the WPB’s request for greater production, ex- periments were made wth commer- cial type fusible alloy cast around the forging and subsequently separ- ated into two parts jaws. The need harder and more durable material led the development jaws cast from Kirksite alloy widely used for drop hammer dies the aircraft industry. The system making these jaws P | C + hold used hing sary jaws alloy high mer- ifac- fol- pro- Operation Sheet for Chucks Turn and face one end sample forging. Insert turned end mold adapter bushing. Preheat mold. Pour Kirksite alloy around sample forging mold. Turn o.d. Kirksite slug and square one end, holding protruding end forging collet chuck. Face other end length, holding slug body three jaw chuck. For adaptation oversize collets, drill and counter- bore four holes for '%-in. socket head screws. (7A) For adaptation two-jaw air chucks, mill two %-in. wide slots body. (7B) Drill and tap two holes each milled slot. (8) Saw slugs half, using 1/16-in. milling saw. (9) Knock out sample forging halves (scrap), mark iden- tification. (10) Tape halves together, and place tool crib. (2) (3) (4) (5) (6) (7) production basis has revolution- ized the machining such forgings this plant. Believing that tre- mendous number man-hours can saved its introduction into other plants, the management American Products making public the procedure. further this purpose, engineering service and data are freely offered those interested. The system was developed close cooperation between the engineering department, Rudy Rosenow, superin- tendent, and his assistants, George Erkelens and Joe Durgin. Its value lies its universal adaptation the various types clamping fixtures, chucks, oversize collets and vises used throughout the shop such machines multiple-spindle chuck- ing machines, wire-feed screw ma- chines, turret lathes and drill vises. Two sizes jaws, and in. accomodate practically all the hydraulic fitting forgings processed. Made sets five pairs they can used chucking ma- Special chuck jaws for holding forged aircraft tubing fittings can made casting Kirksite alloy about sample forging, then machining the jaws out the slug. LENZ Chief Engineer American Screw Products Los Angeles ° chines for long runs. run needed, any set can mounted two-jawed air-chucks, Barker wrenchless chucks special over- 1G. 4—Pouring the Kirksite preheated molds (See Fig. Un- derneath the special stand gas pipe with slit orifices for preheating. The lat- ter operation done while the permanent molds are laid their sides. Melting pot and pyrometer are seen the back- ground. Pouring temperature 820 deg. holds the two halves the gether. (Left) Solid slug comes the mold. between the split halves the mold the sam- ple forging ter) held the adaptor bushing. Be- fore the machined end the forging pushed into the adaptor, the whole piece sprayed with separator. ° ° size collets American Screw Prod- ucts design. drill-press opera- tion needed the jaws are mounted air-operated vise (see Fig. 10): — | need erial = od | ° ° ° THE IRON AGE, August ABOVE 8—Various stages the production impression- cast chuck jaws. From left right: Solid cast slug with machined end forging protruding; drill jig plate for end holes for adaptation oversize collet chucks; set jaws for attachment two-jaw chuck; jaw halves showing typical impression-cast cavity, and two jaw halves for holding T-joint. The split sample seen the foreground. the background wooden carrier with set five cast jaws taped together. RIGHT 9—Adaptation cast jaws the false jaws Barker wrenchless chuck turret lathe. 56—THE IRON AGE, August 1943 LEFT the slots the side chuck body corresponding that shown Fig. The same fixture also used for holding the slug during the slitting opera- tion. For and T-fittings held jaws for oversize collet chucks milled slots required), line scribed the faced end the sample forging parallel the other leg direct the separation the Kirksite casting into halves. Prior milling, the slug turned the o.d. and the ends are squared. For this work, the machined end the sample forging held collet chuck. ABOVE will tapped. the mounting holes for two-jaw chucks. Later these holes é 4 4 . @ The so-called “beginners” class labor can used all operations and pair jaws can completed min. With division labor, set five pairs jaws can made approximately hr. Essentially, the process consists casting the Kirksite alloy perma- nent mold (Figs. and about sample forging blank which has been machined one end, Fig. This leaves solid, cylindrical chuck body with the machined end the forging protruding. provides finished sur- face for chucking the assembly while turning and facing the Kirksite body. some designs (see Fig. the body must milled out fit the jaws two-jaw air chuck special false jaws. another design, four holes are drilled and tapped the end the body for in. socket head screws for adaptation for oversize collets. The slug then sawed halves. The split parts the sample forging are knocked out, the halves are marked and after being taped together are sent the tool crib suitable wood containers shown Fig. The illustrations show the equipment used and the various steps the manufac- ture these chuck jaws detailed the table. The company has found that oper- ators and set-up men prefer this type jaw the old machined kind. Since they require shimming adjust- ing and with the work rigidly held due the large area contact, they product superior work. With the best toolmaking skill, conventional steel jaws can rarely set ready without losing valuable productive time. The impression-cast jaws can ° ° ° 10—Use cast jaws press. This makes cient fixture for drilling el- bows since positive location each forging assured. mounted very quickly and the forg- ing will run true. This makes machining allowance the forging only 1/16 in. the diameter in- stead the not uncommon allowance jaws good for 8000 10,000 opera- tions without loss accuracy. Rapid and economical jaw replacement makes this process marked advance shop practice. American Screw Products now experimenting with design mold which will cast the jaws completely cored, slotted and sized that split- ting into halves will about the only operation necessary prepare the jaws for use. New High Impact Molding Plastic AKELITE CORP., unit Union Carbide Carbon Corp., has announced the development new high impact-resistant molding mate- rial, BM-16468. black phenolic plastic having string filler, rather than chopped fabric which employ- for other types shock-resistant materials. Impact strength BM- times greater than general-purpose phenolics. Molded specimens indicate the materials have the following physical properties: Compressive strength, per sq. in. Tensile strength, per sq. in. Flexural strength, per sq. in. Maximum deflection, in. Impact strength, Energy break, per in. notch Direction Stress Parallel 27,500 32,700 Transverse 15,600 18,200 Transverse 7,500 58,00 Parallel 12,000 12,900 Transverse 10,200 14,200 Transverse .095 .118 Parallel 4.84 1943—57 eee ] 3 les les ‘ major objection shaving gears the aircraft industry seems center around the probability distortion during heat treatment subsequent finishing the gear tooth form. Considering distor- tion rather expansion, sometimes uniform and sometimes non-uniform, method control suggests itself. Heat treating procedure changed make more uniform and allowance introduced compen- sate for the uniform expansion cutting the gear originally. During the development the 1937 Chevrolet transmission series Shaved Gears for checks was made transmission gearsets determine whether the volume change during heat treatment was uniform expansion. Produc- tion gears made SAE 5145 steel were hardened immersion cyanide bath 1490 deg for ap- proximately min. and then quenched oil. Development gears made SAE 4815 steel were carbu- rized 1675 deg. F., cooled the box, reheated 1470 deg. and quenched oil. The involute form the gears was charted before and after hardening. The change was then converted into Expansion Rates During Heat Treatment Passenger and Commercial Transmission Gears Passenger Commercial Clutch Gear Dimension over gage Dimension over rolls clutch Bearing Diameter.............. Dimension between rolls spline Second Speed Gear Dimension over rolls clutch Length Countergear tooth Dimension over gage Dimensions over rolls teeth. tooth Dimension over gage Outside 5145 Steel 4815 Steel +.0007 .0002 .0006 .0040 .0002 .0022 .0002 .0018 +.0011 +.0011 .0007 .0007 .0033 .0016 +.0011 +.0011 IRON AGE, August 1943 corresponding change base circle diameter and compared change other gear elements. The expansion rates are shown the chart, Table While will noted that all ele- ments the SAE 5145 steel gears did not expand uniformly, can seen that the change the tooth form part the general expansion the gear during heat treatment. be- lieve that changes the holding fix- tures used during heating and quench- ing control the cooling rate the gear would have resulted form expansion. However, since the gear teeth themselves expanded quite uniformly, felt that changes control the other elements were not justified. the basis these re- checks both plants manufacturing these gears, allowance for expan- sion during heat treatment 0.0010 in. was established for the SAE 5145 steel gears. The fact that aircraft engine gears are normally carburized only locally and the case depth more closely con- trolled will probably make them ex- pand more uniformly. Expansion data the tooth form one gear for aircraft engine use that shaved and carburized shown Fig. This impeller shaft gear the left has teeth 11/13 diametral pitch. The vertical points the tooth chart indicated are the lowest point con- tact with the mate, the pitch line and the tip the tooth. This gear being shaved production rotary shaver, carburized gas carburizer and hardened elec- tric furnace. The bulge near the pitch line characteristic carbur- ized gears and confirms the variation expansion rates given the table. tends relieve the tooth load the tip the gears and not detri- mental their operation not ex- cessive. The expansion rate this gear tooth 0.0006 in. The gear the right was handled the same procedure but showed entirely different expansion charac- teristics. This, believe, was due the change section and the re- ele in. ter inf isk | sil TABLE First and Reverse Gear Dimension over gage blocks Gear Diameter between gears............... circle the The the ele- did seen 3 the be- fix- ench- the uni- the quite not re- spot the cally con- data for and This has con- and gas elec- the ation able. etri- this due Aircraft sultant change cooling rate. fixture designed quench the tooth elements this part the same rate the other should change its expan- sion rate from 0.0020 0.0006 in. While there difference ma- terial, one being AMS 6240 and the other 6294, this not believed influence the rate materially. This second gear present being fin- ished grinder. Preliminary data collected for the uevelopment shaving cutter forms suow range expansion rates from 0.0003 0.0012 in. the teeth six different gears investigates. The sections these gears are com- parable that shown the left Fig. Development Fillet Contours Another objection shaving fre- quently expressed the probability highly concentrated stresses due cutter marks and the line demarca- tion between the hobbed and shaved contour the tooth fillet. Early our experience with shaved automotive transmission gears were called upon strength 14-tooth pinion pinion driving 33-tooth gear. Since higher gear ratio was also desired, substituted 13-tooth pinion cut out the same blank and mating with the same 33-tooth gear. well getting the increased strength and ratio desired, unanticipated advan- tage was obtained. The heavy tip contact had been perpetually fight- ing shaved gears virtually disap- The subsequent Chevrolet transmis- sions designed shaved incorpo- rated dual pressure angles the gears—a generating pressure angle and higher operating pressure angle. This pemitted the involute form generated lower than the mating gear contacted without the depth the tooth. However, did decrease the strength the tooth narrowing the base. This was com- pensated for putting radius, tangent both sides, the tip the hob. The result was slightly increased depth tooth, but HARRIS Chevrolet Motor Division, General Motors Corp. ° Today, the War Department asking industry use gear shav- ing wherever practical for the manufacture aircraft engine gears. About years ago shaving was adopted for finishing auto- motive transmission gears order get smoother tooth contact and eliminate the matching gears decreasing variations tooth form. This time the change procedure for the purpose relieving expected equipment shortage spreading the re- quirements over more types machines. This report, originally presented paper before the Society Automotive Engineers April, details some experience shaving transmis- sion and aircraft gears and points out some the problems encountered. stronger tooth than one designed the usual procedure, due the fact that the radius the tip the hob reduced the stress concentration the base the tooth. This procedure was used laying out hobs used prior shaving aircraft engine gears. While not highly stressed gear, 7-tooth oil pump gear was laid out this manner and will serve illustra- tion the method. The tooth has been made shallower than standard permit the use larger shaft. The nominal clearance over the tip the mating gear only 0.004 in. This 6-pitch gear deg. pressure angle originally ground with showing gear tooth expansion aircraft engine impeller shafts during carburizing and hardening. The dimensions the left each chart are distances along the line action from the point tangency with the base circle. The spaces between adjacent vertical lines represent 0.0005 in. Max 0.592 Pitch 0.4