The Iron Age 1944-11-16: Vol 154 Iss 20

VAN DEVENTER President and Editerial AGE Vol. 155, No. BAUR General and Advertising November 16, 1944 Business Managers New York New York 42nd St. 100 East 42nd Cleveland Pittsburgh Technical Articles Electric Furnace Brazing Being Widely 310 Woodward Ave. Box Appraisal Precision Thread Practice HERMAN HOTTENSTEIN Equipment and Material for Precision Casting (Part ° ° Address, ° ° Index Advertisers 2420 Cheremoya Ave. Continuous Electro-Zinc Plating CHILTON COMPANY Features WILLIAM BARBER, Treasurer JOHN BLAIR MOFFETT, Secretary JULIAN CHASE THOMAS HARRY DUFFY HEALE News and Markets Member, Audit Bureau Circulations Delivery Schedule Bus for British Compensation Plan Awaits Steel Construction Institute Sees Big 130 Midwest Spot 142 Screw Machine Surplus Threatens 156 Machine Tool Market 166 Non-Ferrous Metals News and Prices 168-169 Iron and Steel Scrap News and 170-171 Comparison Prices Week and 172 Finished Iron and Steel, Steel Prices.............. 173 Steel Pipe, Tubing, Wire Products, Prices 176-177 North South and Pig Iron and Coke Prices 4 Stainless Steel and Ferroalloy Prices 180-181 ° mpany 285 ington Best Source There more time for creative business-planning when executives recommend Ryerson Steel Service their companies’ source for steel. Here are the plus values that explain why Ryerson Steel Service the best source for steel products: Ryerson complete stocks include more than 10,000 different kinds, shapes and sizes steel. Deliveries are made promptly truck and rail. When needed item cannot delivered from one Ryerson plant, service available from the other plants. Ryerson quality uniform and dependable. Ryer- RYERSON STEEL-SERV 44—THE IRON AGE, November 1944 son metallurgical and engineering counsel are high value. Technical data hardening furnished with all alloys. Ryerson Steel Service represents 102 years busi- ness history. prove its plus values, place your next order, large small, with your nearest Ryerson plant. Meanwhile, send today for Ryerson Stock List. JOSEPH RYERSON SON, INC. Steel Service Plants at: Chicago, Milwaukee, Detroit, St. Louis, Cincinnati, Cleveland, Pittsburgh, Philadelphia, Buffalo, New York, Boston. Tec Co: ‘ 4 4 ESTABLISHED Nov. 16, 1944 VAN DEVENTER President and Editorial BAUR Vice-President and General s DIX Manager, Reader Service Editorial Staff Technical Editor......... OLIVER Associate Editors WINTERS ALBIN ANTHONY JACK HIGHT BARMASEL Editorial Assistants SCHIEN WILLIAMS O'CONNOR MILLER News and Technical Pittsburgh 428 Park POST Chicago Otis Bldg. MOFFETT DONALD BROWNE HARDY National Press Bidg. LLOYD Cleveland BRAMS Woodward OSGOOD MURDOCK Market Correspondents ROBERT Cincinnati DEAN Buffalo PRAZAR Boston HUGH SHARP Milwaukee SANDERSON Toronto, Ont, KAY Los Angeles JOHN McCUNE Birmingham ROY EDMONDS Louls JAMES Seattle Back Home Again ETURNING home after seven weeks abroad war ravaged country makes one doubly appreciative being American. would wonderful thing could send our citizens abroad ten twenty thousand lots that they might better appreciate the privi- leges and benefits working and living our country. Take, for example, such elemental thing eating. The British Isles, thanks largely lend-lease, have had enough eat but the repetition preceding menus. Some restaurants London disguise this best they can printing the bills fare French, but jugged hare and braised pigeon taste the same any language. for pow- dered eggs, which are the only kind available, and pork sausage with conteritvef ten per cent pig and ninety per cent corn meal, the less said the better. Next the desire for variety food comes another simple need, that shelter. not particularly appealing have sleep shifts the home relative friend because your own house has been destroyed, cot subway station many are still doing because they have friends relatives with available beds. Nor, still more are doing, partially destroyed homes with tarpaulins cover- ing gaping roofs and with the wind blowing through glassless win- dows. Imagine how New York you Philadelphia Chicago any metropolis would feel these cities nearly million homes had been rendered uninhabitable bomb damage. Worst all, from the psychological standpoint, has been the black- out. have never had real blackout this country; complete absence all light, even the faintest glimmer. Great Britain curtains must drawn sunset and kept drawn until sunrise; skylights factories have had the glass replaced with wood metal and roof ven- tilators have had completely closed avoid the slightest glow. result, ventilation night both homes and factories just some- thing that isn’t and nightshifts metal working and steel plants par- ticularly have experienced almost intolerable working conditions. Trials and tribulations this sort develop heroes the home front, just battles the war front. The story was told watcher, stationed elevation adjoining war plant, whose duty was watch for buzz bombs and sound the alarm when one was headed that direction and seemed likely hit the plant. the days when many these were coming over, workers did not take shelter the ordinary alert alarm but waited for the local observer advise them damage were imminent. They could not afford interrupt production unless absolutely necessary. One night, after the siren blew, the observer reported bomb headed directly toward his station and the plant. “It’s coming this way, boys,” said. tell you minute it’s necessary for you take shel- Then: “Keep working, fellows, safe, it’s falling right here station. Goodbye and God bless you.” cite these things because Thanksgiving coming and indeed have something thankful for that live America. a | | high ervice Louis, THESE FIGHT Mud, sand, water they all are the same the Studebaker Corporation’s officially the combat forces the M29 cargo and personnel car- rier. Powered standard six-cylinder Studebaker Champion engine, this track- laying vehicle designed strike swiftly and stealthily over greater variety ter- rain than any other military conveyance. Inland’s part the production sels” was furnish 18-gage Hot Rolled Pickled Sheets for the all-welded. water- tight hull; and 9-gage steel for hull rein- forcements; 10-gage sheets for cold pressed guide wheels; 13-gage steel for the cold formed bogie wheels and silicon manganese spring steel bars for the four springs each Inland has maintained remarkable assure water Deep mud steep hills cannot stop the fighting record deliveries and uniform high that has speeded many fighting fronts through- out the world. Floor Plate, Piling, Plates, Rail, Reinforcing Bars, Sheets, Strip, Structurals, Tin Plate, Track Accessories. Inland Steel Company, Dearborn Street, Chicago Sales Offices: Cincinnati, Detroit, Kansas City, Mil- New York. St. St. Paul. Welding the hull for Three submersion tests are made strip. Republic's Warren plant, employing the direct reduction process, News FRONT November 1944 Lowest cost producer the nine DPC aluminum reduction plants throughout the nation the Alcoa operated plant Meade, showing cost 11.87c. lb. for ation, excluding overhead, which might add another quarter cent lb. Most recent War Department figures show that 29,354 fixed price contracts have been cancelled and this amount 25,560 have already been settled. These would have cost approximately $12,000,000,000 complete. dollar value 280,000 worth has been settled payment contractors $330,100,000. ft. per min. Coating weights range from 0.1 0.2 oz. zinc for each square been operation about month. Considerable difficulties have been encountered, the product now about per cent metallic Fe, whereas reduction the But: The many operational problems are being ironed out and better results prospect. their latest raid the Japanese homeland report seeing Jap twin-motored fighter very fast. Enemy propaganda has recently claime quantity production airplane, similar but superior famed British Mosquito. Centrifugal casting boomed panacea for foundry production problems, was back the recent abandonment large mid-western foundry its equipment centrifugally casting cylinder sleeves. Surprisingly enough, porosity was troublesome and machining costs proved highe than for static castings. Sweden has absorbed refugee aliens the amount almost per cent its total population, mostly Norwegians, Danes, and Finns. Sometimes the British press gets involved its inconsistencies the Ame can. Despite traditional liking for the Italians, the London press has waged violent vendetta against use Italian for repairing damaged London because the prisoners were lodged housing suitable for Civilians. Consequently the prisoners have been removed and the houses are not repaired. press meanwhile demands that British rebuilding carried out German oners after the war. Cancellations steel Great Britain has caused four steel compa ies Another factor reducing the steel operating rate has been the falling off the demand for open hearth and electric furnace alloy steel. the demand ammunition steel may make for this Lack trained crews and insufficient fuel are preventing the Germans from ting their full strength into the air, General Arnold revealed recently. The waffe, however, has more planes now than ever before. The limited range jet planes gives Germany advantage that able send them defend strategic points. The United States yet unable jets out protection for bombers because the longer distances involved. tain respects, German jet propulsion planes are superior many the orthodox the United States. greatly increased strength and toughness have been developed Bri ain. flux (containing borax, sand, and copper oxide) de-gassing process enables bronzes and phosphor bronze produced from ordinary commercial grades from scrap. The stimulus the success the electrolytic tinning line has resulted 160 has the RIOR 1929, the electric fur- nace brazing process was rela- tively unknown. Its use was largely limited the manufacture only few products, such tungsten contacts, golf shafts and various parts for steam turbines and electric refrig- erators. The use the process stead- ily increased during the succeeding years, however, and when the present war started, furnace brazing was rather generally employed the manufacture parts for automobiles, refrigerators and business machines. Thus, familiarity with the advan- tages furnace brazing manufac- turers such parts resulted the fabrication many subassemblies which might otherwise have forged, cast machined from solid stock. Furnace brazing subassem- blies made stampings, screw ma- chine parts and tubing has materially speeded production, reduced costs and released much needed forging and machining capacity for other impor- tant work. Furthermore, these parts come from the furnaces with clean, bright surfaces and strong, tight bonds, thus presenting good appear- ance and assuring long life. Furnace capacity has rapidly in- creased meet current demands. The number brazing furnaces installed during 1941-43 was equivalent 48—THE IRON AGE, November 16, 1944 ° ° LEFT cam- shaft for aerial cam- era before (center) and after (right copper brazing con- trolled atmosphere elec- tric furnace. Typical component parts are including preplaced copper wire rings. Heavy lines sketch indicate penetra- tion brazing metal throughout all joints capillary attraction. vary from tiny parts for aerial cameras, measured fractions inch and weighing less than ounce, large cooling fans for motors and generators ft. diameter and weighing 400 lb. Equipments utilized range from small box-type furnaces that can put the corner shop laboratory directly the production line, large roller- hearth conveyor-type furnaces 160 ft. long. Thus has been found that the furnace brazing process has great adaptability wide ranges sizes and weights assemblies well rates production. RIGHT 2—Tray load aerial camera parts about charged type copper brazing furnace. those installed during the whole 1929- period. addition, new type combination brazing ing furnace has been developed. With existing brazing furnace capacity now estimated over 150,000 net per hr., large number unique and interesting assemblies are now pro- duction and unquestionably there will still other new applications this process time goes on. Typical furnace brazed assemblies typical example the use fur- nace brazing for fabricating small as- semblies the manufacture parts for aerial cameras. When reconnaissance plane travels hundreds miles get some pictures, every- thing possible must done assure dependability the working parts the camera such the shutter mechanism. For this reason, the Fair- child Camera Instrument Corp., Ja- vA \ q 4 “NY — q maica, Y., has found advanta- geous use furnace brazed assem- blies place riveted pinned ones wherever possible. Riveted pinned assemblies are subject working loose service due the severe im- pacts and vibrations they receive. Furnace brazed ones, however, being much stronger, are highly dependable and said, never work loose. Also, due their great strength, they can made considerably smaller. Elim- ination the extra size formerly re- quired for the pins gives further re- duction volume. These advantages have made possible build the cameras more compactly, decreasing both their size and weight. Manufacturing savings are also realized because the cost the fur- nace brazed assemblies considerably x 3—Typical brazed bond between two SAE members. 1010 less than that the riveted pinned ones. Pinned assemblies must set jigs and carefully drilled and reamed for tiny tapered pins, such assembling costing the order three times much for the assem- bling parts for furnace brazing. The biggest cost however, are the making individual parts. For example, the cams the cam- shaft Fig. were taper-pinned the photomicrograph copper- steel ° ° ° Industrial Heating Division, General Electric Co., Schenectady ° ° Production war goods has provided fertile field for the extension electric furnace brazing. the first two part article, Mr. Webber, who has written many articles this subject before, illustrates how stampings brazed each other screw machine parts have replaced other methods fabrication the manufacture ordnance and aircraft components. main shaft, the cams with their integ- ral collars would have hogged out solid stock. For furnace-braz- ing, however, the cams are simply blanked out punch press and the two collars and two nuts are made automatic screw machine, all about one-tenth the cost ma- chining integral cams and collars for pinning. consisting SAE 1020 steel cams and spacers pressed shaft. Copper wire rings, placed the joints during assembly, provide the brazing metal and melt the furnace heat ap- proximately 2050 deg. The copper drawn into and throughout all joints capillary attraction indi- cated the heavy lines the sketch, making uniform bonds having great strength. After brazing, the assem- blies are case hardened. Fig. shows trayload typical camera parts prepared for brazing and ready charged into box type, copper brazing furnace. This furnace has heating chamber with nickel-chromium, ribbon-type electric The camshaft illustrated approxi- mately in. long and weighs about oz. fabricated from eight parts, BELOW Furnace- brazed insecticide made three heating units for 2100 deg. maxi- two screw machine waterjacketed cooling chamber. Pro- tective atmosphere maintained both chambers. Inasmuch the work both heated and cooled this at- mosphere, the parts come out clean and bright, with smooth, neat copper fillets the joints. parts and piece tubing, all low car- bon steel, with five joints brazed simultane- ously. The long camshaft previously shown Fig. denotes relative size. THE IRON AGE, November a rial an nce, and and zed ces the ft. the eat zes | typical copper brazed joint between two pieces steel. The bond across the center the field. this in- stance, the line copper longer tween two flat surfaces, but now broken grains the steel which have actually knitted across the joint; also the copper has alloyed with the steel, darkening the grains the in- terfaces. The copper has also taken iron into solution, some which has probably been thrown out upon cool- ing and seems indicated the iron-rich particles shown the bond. All these knitting and alloying actions contribute high strength and generally give bonds which are great deal stronger than copper. Tight Joints Freon Bombs furnace-brazed item which has been made very large quantities for the Army the insecticide bomb (Fig. 4). this illustration and subsequent ones there shown the 1-in. long cam shaft previously il- lustrated Fig. convey the rela- tive sizes the assemblies. The con- tainers are filled with non-toxic gas under pressure, consisting Freon, pyrethrum and sesame oil, sprayed into tents foxholes sol- diers, killing bugs insects, pro- tect the men from disease. The joints the containers must strong and tight inasmuch the Freon very difficult hold. Typical these in- secticide bombs the one shown, brazed the Salkover Metal Proc- essing Co., jobbers furnace brazing with plants Chicago and Long Island City, Y., for the Armstrong Engineering Co. and the Tetco Co., both Los Angeles. Five joints are brazed one trip through the furnace, thus contrib- uting low overall cost and uniform 50—THE IRON AGE, November 16, 1944 LEFT 5—Copper brazed end magazine for chine gun. When copper right) the liquid brazing metal drawn along the seams consider- able distances capillary attraction. brazed magazine end plates, with clamping fixtures, emerging from discharge end mesh-belt conveyor type copper brazing furnace. 7—All-copper furnace brazed with copper oxide and silver oxide powders hydrogen atmos- phere. quality. The punctureable brazed into the dispensing tube, the tube brazed the valve, the valve brazed one cup, the two cups are brazed together the midseam and the tail fitting brazed into the other cup. After brazing, the containers are tested 200 lb. pressure with carbon dioxide gas and the bonds are found ing snug fits the assemblies before brazing, which very important, trouble encountered holding the Freon without leakage ment. Also, felt that the uniform ductility the metal after furnace brazing, without brittleness near the bonds, definite advantage. Copper Creeps Long Distances unique furnace brazed assembly the end plate for the magazine the Oerlikon 20-mm. anti-aircraft gun. Fig. shows the rear-plate assembly, made seven pieces, all copper brazed together one pass through the furnace. The rear plate punch- ing made from cold rolled SAE 1010 steel with spiral grooves swaged accommodate two spiral guides rolled and formed from SAE 1020 coil stock. journal flanged ring pressed into the center the rear plate and staked, then two stop pins are riveted place. The rear attachment block, For basic data the fundamentals the process, the reader referred the following articles Mr. Webber which have appeared THE IRON AGE: Brazing: Where and Why Use It," Sept. 1938, 34; “Holding and Supporting Assemblies Electric Furnace Sept. 15, 1938, 30; and Supporting Assemblies Electric Furnace Sept. 22, 1938, 46; Brazing, Capillary At- traction and Wetting Action Nov. 1938, 30; “Limiting Creep Furnace-Brazing Metals (With Data Removing Copper after Nov. 10, 1938, 44; “Applying Electric-Furnace Brazing Nov. 24, 1938, 28; Furnace-Brazing Metals and Dec. 1938, 48; “High Strength Furnace-Brazed Joints Dec. 29, 1938, 30; “Furnace Brazing Cast Iron (With Notes Causes Dis- tortion Furnace Brazed Feb. 1939, 55; “Factors Affect- ing Selection Furnace-Brazing March 16, 1939, 30, and for Furnace-Brazing April 1939, 46. The complete series available reprint form from the General Electric Co., Schenectady. which forging SAE 1022 steel, projection-welded the back the plate. Then the spiral guides are laid the grooves and locked place wedge-type clamps. Capillary Effect Almost unbelievable those with- out furnace brazing experience the method which the brazing metal applied and the results obtained. braze the spiral guides the rear plate, only nine small copper “hair- pins” about in. long, made 0.102 in. wire, are hung over the top edges ABOVE 8—Two box-type electric furnaces with molybdenum heating units for 2400 deg. maximum operating temperature, used for silver brazing tube radiators 7), also for copper brazing, normalizing and annealing, and for removing certain gases from metal parts. RIGHT 9—Assembly steel fittings composed pieces, copper brazed single furnace operation. the spiral guides. Wire rings are placed over the journal and stop pins, and coils copper wire are placed two holes the plate directly over the rear attachment block. When the hairpins melt the controlled atmos- phere brazing furnace, the copper runs down the sides the spiral guides and into the grooves, then creeps around the joints capillary attraction, some cases far in. (not unusual distance), leaving smooth, neat fillets all the way. The other rings and slugs also melt and or n. iw THE IRON AGE, November solidly bond their adjoining members together. Fig. shows the discharge end mesh-belt conveyor-type copper braz- ing furnace the National Cash Reg- ister Co., Dayton, Ohio. Brazed end plates with locking clamps place are shown emerging from the exit end the cooling chamber. After the clamps are removed, the end plates are stacked carriers shown the right. The mesh-belt furnace similar arrangement the box-type furnace previously shown, that has heating chamber and cooling chamber, both with controlled atmosphere. However, differs that has heat-resisting alloy wire mesh con- veyor and pulleys both ends. Thus, work loaded directly the con- veyor and carried continuously through the furnace speedy speed, the rate this speed being adjustable 10—Operator tying copper wires around fittings tack welded tubes, preparo- tory furnace brazing controlled atmosphere electric pit-type furnace. Reeves speed changer the drive mechanism. Silver Brazing Copper Parts Fig. shows all-copper cooling radiator for vacuum tubes used transmitters. ingenious ar- rangement outer shell, inner shell, plug and fins, held position with cast-alloy fixtures and brazed to- gether with eutectic mixture copper oxide and silver oxide powders mixed with water and applied the joints with brush. The assemblies are brazed furnace temperature 1640 deg. Fifteen them are loaded tray and charged into one the box type, controlled atmosphere electric furnaces (Fig. 8). The tray rests the heating chamber about min. and then pushed into the cool- ing chamber. The assemblies come from the furnace with uniformly over 6:1 range means strong, tight bonds, having good brazing, the assembly shown Fig. now has uniformly tight bonds. smooth, neat fillets and clean, bright surfaces. thermal conductivity, and scale flux removal required. The assem- bly shown Fig. was made Gen- eral Electric X-Ray Corp., Chicago, and the box type brazing furnaces, Fig. are installed that plant. These furnaces have molybdenum-rod resistors for 2400 deg. maximum operating temperature. Similar ones have been built for 2750 deg. Another assembly which illustrates the advantages fabricating with the furnace-brazing process periscope sight tube, tube with various fittings, Fig. This assem- bly made pieces, all copper- -brazed together one operation. The main piece section SAE 1040 tubing, about in. o.d., in. wall thickness. are assembled four SAE 1020 forgings, one steel casting, four sleeves made from short sections tubing, and number pads, brackets, bosses, made from ma- chine steel. The overall length the assembly about in. Tack Welded First The various component parts are tack-welded place, shown the close-up view Fig. 10. This photo- graph shows the copper wires being tied around the parts preparatory brazing. After the assembly has been brazed retort pit-type con- trolled atmosphere furnace, has the appearance shown Fig. The copper has run throughout all joints, firmly and tightly bonding the vari- ous fittings the tube, and leaving smooth, neat fillets all junctions. highly important that the bonds are not only strong but that they are airtight, and the furnace brzing proc- ess has been found ideally suited this application these respects. The assemblies are pressure tested after brazing and leaky joint quite rare. With snug fits and good tack welding technique hold the members close together, has been demonstrated production that the copper brazed joints are uni- formly strong and tight. The above operations are carried one the General Co.’s plants. [Other examples furnace brazing applications and developments equipment will illustrated Mr. Webber next > q 52—THE IRON AGE, November 16, 1944 on) FUNDAMENTAL that claimed for induction melting small metal charges compared with other methods the uniform temperature throughout the charge obtained inducing electric currents through it. Another advan- tage the stirring effect molten metals, particularly important the alloys. High frequency induc- tion heating can give extremely high energy input the mass melted. This immediately causes rapid melting with inherent reduction oxidation and contamination, and with the introduction reducing atmos- phere surrounding the melt, practi- The components high fre- quency induction furnace are cruci- ble and coil copper tubing through which cooling water circulates. This coil placed around the crucible close constructional and tempera- ture limitations permit. The metal charge—or the crucible itself, electrically conducting material winding transformer which the induction coil the primary winding. The coil energized generator the low fre- quency current from the a.c. power supply line into current high frequency usually within the range 500 kilocycles. The drawing, Fig. shows typical cross-section through induction furnace with crucible the non-conducting type. Induction heating, with its ability concentrate large amounts en- ergy small masses, gives advan- tages not obtainable with other meth- ods melting from point view centrifugal casting. The melting cru- cible can made any desired shape form fit into the casting procedure and moreover, can placed any desired position with respect mount the melting crucible adjacent the mold the rotating arm which gives the centrifugal force the molten metal, and have the heating Equipment and Material For Precision Casting this second and concluding article, induction heating fur- naces and centrifugal casting machines are described. ALBIN coil mounted such way that can brought over the crucible dur- ing the melting cycle and removed when the casting operation taking place. Manufacturers induction heat- ing units have experimented with methods that make the maximum use the flexibility and the cleanliness the induction process for centrifu- 9—Cross section induction heat- ing furnace with pro- tective gas. Courtesy Ecco Hiah Frequency Corp 4 c crucible bas gal casting. Several suggested pro- cedures under development the In- duction Heating Corp., 389 Lafayette Street, New York are here de- scribed. Multiple stations can arranged that one crucible heating while others are being emptied, thus guar- anteeing full utilization the equip- ment involved (Fig. 10). This only -Refractory cover Crucible clamp cooled coil High frequency Dower THE IRON November -rod num ates with the ; with per- The wall four ‘ing, ads, ma- the are the oto- con- the The nts, ons. are roc- The fur- Asbestos housing source IG. Casting proposed mul- machine tiple unit operation from single high frequency generator. crucible tion gested bottom tap- ping crucible allow new metal fed continuously top crucible with fluid state. High alloy insert Ceramic 12—Principle the spout type crucible which per- mits metal heated even when flow started. Metal begins rise spout rotation commences. 1G. 13— Method locating re- movable heating coil about crucible trifugal casting ma- chine. Courtesy High Frequency Lab- oratories. mounting plate mounting for crucible IRON AGE, November 1944 one example the many techniques which can developed. Many manu- facturers have preferred keep the melting setup apart from the casting apparatus, and have used larger cru- cibles feed many molds. has been possible such use bottom tapping crucibles, Fig. 11, which allow new metal fed continuously the top the crucible while clean superheated metal the fluid state drawn off from the bottom. Multi-Spout Crucible Another adaptation these prin- ciples has been the multi-spout cru- cible mounted the center the spinning platform whereby the heat- ing coil, surrounding the large cru- cible mounted the axis rotation, could left place during the spin- ning and casting part the proce- dure, and permit the metal heated even when the flow has started. The crucible for such installation much resembles the shape spider, each leg being spout butted against its individual mold, practice, six, eight even ten (Fig. 12). These spouts have rise them after they leave the body the cru- cible that when the crucible rest, the charge molten metal does not flow from the spouts. The heating coil arranged that heating also takes place within the spouts, pre- venting metal from solidifying them. Upon rotating, however, the molten metal tends flow outward against the sides the crucible, and this pressure causes the melt rush into the spouts and from there, into the molds. More metal added the crucible, and during the short interval time required for melt, new molds are placed position and the process ready for another run real production basis. method mounting crucible for melting when centrifugal casting has been develoved another induc tion heating company and shown Fig. 13. Immediately after the melt secured, the coil slipped away from the crucible and the centrifuge released. Induction Furnaces The Ajax Electrothermic Corp., Di- vision the Ajax Metal Co., Trenton has line converters and fur- 200 lb. These are follows: kw. converter, usual frequency about 50,000 cycles, maximum recom- melt (carbon free) kw. converter, usual frequency about 40,000 cycles, maximum recom- melt (carbon free) 7 Heating Spouts ate ting also pre- the and rush here, dded short sition other icible sting nduc melt away Di- fur- juency recom- free) recom- free) kw. converter, usual frequency about 25,000 cycles, maximum recom- melt (carbon free) —30 (see Fig. 14). kw. converter, usual frequency about 20,000 cycles, maximum recom- —50 Generator powered equipment rated 100 kw., 3000 cycles, with 200 lb. fur- Generator powered equipment rated kw., 2000 cycles, 150 furnace for hand pouring used with the kw. Ajax Northrop converter illustrated Fig. This photo was taken the plant Trifari, Krussman and Fishel, 387 Charles Street, Providence used with the kw. converter de- pending upon the charge required. The melting time for steel approximately min. The cast- ings produced the present date this plant range from fraction alloys and ferrous mate- rials. The casting machine shown company design and manufacture. The company has order Ajax motor-generator type melting unit one time. When this installed, the plans split the heats into method for maintaining product uni- generator powered Ajax Northrup ° RIGHT 14--Metal Being poured from the ca- pacity Ajax induc- tion heating furnace with trunnion mount, i RIGHT Ajax Northrup furnace with melting ca- pacity 100 The molten metal will conveyed hand ladle the centrifugal casting machine the fore- ground. furnace permitting hand pouring into centrifugal casting machine. the back- ground Ajax kw. converter. £ % LEFT THE IRON AGE, November tion furnace which melts oz. steel protective gas outlet top edge furnace installation 100 ca- pacity. The ladle type induction furnace uniquely fitted for pouring the melt into the casting machine. furnace produced Ecco High Fre- quency 7020 Hudson Boulevard, North Bergen, The melting time for oz. steel with this ladle fur- nace sec. with kw. input. The low voltage and current form produced the Ecco high frequency converters makes possible handle the ladle furnace shown the il- lustration, without danger shock. While the metal being melted the furnace rests Transite cradle which may placed furnace table other suitable support. The ing member fastened with nut and can replaced few seconds. Since the crucible assembly comprising cru- cible, insulation and coil liner self- contained, insulating packing required. Provisions are made for maintaining curtain hydrogen other preferred atmosphere above the melt. Ladles are equipped with Ecco double-shell alumina crucibles for steel melting and with carbon-graph- ite crucibles for melting copper, brass precious metals which are not sub- ject carbon contamination. For platinum and other metals with high melting points zirconia crucibles are available with liners fused quartz protecting the heater coil. Ecco ladle furnaces are made three steel melting capacities: 1%, and Ecco furnishes hand pouring box type ladles with gas curtain jet in- duction furnaces, ranging from capacities. For charges ex- manufactures trunnion type furnaces which are tilted either lifting handle back the furnace pulling rod fastened its side. These furnaces are mounted table with Transite top and come two TABLE Recommended Crucibles for Various Metals Weight# Melting Point Crucible Metal per Cu. In. Lb. Deg. Recommended Steel per cent 0.282 2602 0.310 1981 Clay-graphite 0.300 2646 Alumina magnesia 0.092 1218 Clay-graphite 0.720 3191 Zirconia 0.433 2831 Zirconia 56—THE IRON AGE, November 1944 standard sizes—Model F30 with ca- pacity lb. steel and Model with lb. capacity. The Lepel High Frequency Labora- tories, Inc., West 60th Street, New York 23, manufacture induction furnace for manual operation which comes several sizes. Fig. illus- trates ladle type furnace having capacity alloy steel. For heavier melts about lb. fur- nace with tilting table can had. Current for these furnaces sup- plied from standard Lepel high fre- quency converters the quenched spark gap type, variable frequency, that inductor coils different sizes and characteristics can accurately matched. The converters used with Lepel furnaces come capacities ° ° ° ladle capacity. ° ° ° and kw. The kw. unit used with the Ib. furnace. Power requirements depend the amount charge, the kind metal and the time heating desired. Non- ferrous metals copper base alloys generally take from three four times much energy similar mass iron. The following are examples melt- ing periods: Using Lepel kw. in- put converter, oz. stainless steel melt sec. Using Lepel kw. input converter, lb. charge steel requires about min. for melting. Lepel provide ceramic and graphite type crucibles. The latter pre ferred the case non-ferrous melt; the ceramic generally used for melt- ing both magnetic and non-magnetic steels. prevent oxidation, especially the case steels, short heating cycles are imperative. trace oxida- was observed the aforementioned oz. charge stainless steel. Where longer time cycles involved, blanketing with non-oxidizing gas advantage. — n << wall = unit the metal Non- alloys four similar melt- kw. in- steel kw. steel ng. raphite pre melt; agnetic ially cycles oxida- ntioned Where ing gas Fig. shows Lepel induction heating unit and its connection with coil for heating centrifugal cast- ing crucible. Melter and Caster The Thermotrol, combination melting and casting machine pro- duced Jelenko Co., Inc., 136 West 52nd Street, New York 19. Originally developed some years ago for the dental trade, the model illus- trated Fig. incorporates changes size and other features which make the present machine suitable for the commercial field. The machine consists rotating arm which balanced center pivot. Towards one end this arm electrical muffle heating unit which serves melt the metal cast. the outer end this heating unit and tightly clamped against it, the flask which contains the mold into which the cast metal forced. The arm used wind the spring motor the base. Connected source electric power, 120 volts a.c. d.c., the time required bring the muffle casting temperature from 1000 2000 deg. about min. The rate flow current and the tempera- ture the surface the crucible are both indicated meter the panel board. The rate current flow There considerable data exis- tence show that the strength and ductility the casting are affected the temperature which the metal thrown into the mold. This par- ticularly true small castings which solidify very rapidly and which must force the gases out the mold ahead the molten metal very high rate speed. thus seen that the possibility controlling this casting temperature and studying its ef- fects, important the soundness the casting. feature Thermo- trol. The second factor which Thermo- trol controls very well that the atmosphere surrounding the molten metal during melting. The carbon provides almost perfect deoxidizing atmosphere, due the affinity the carbon for any oxide which may present the crucible. This protects the metals against oxides which might form during heat- ing and result obviates inclu- sions the casting. Available for general commercial use Model.J-100 having capacity 0.6 cu. in., equivalent 0.20 lb. LEFT 19—Lepel in- duction heating nection coil. BELOW 20—The Jel- combines single unit electric muf- fle furnace and machine. MELTING FURNACE (Carbon Crucible inside) SELF-CENTERING FLASK CRADLE \ LOCKING BACK PLATE LECTRICAL CONTACT SYSTEM CONTACT LEVER CASTING CHART RHEOSTAT = q KNOB _ MELTING CHAMBER DOOR phosphor bronze. For larger castings, there Model I-3 having capacity 2.2 cu. in., equivalent 0.70 metal. The smaller model takes 3.5 in. outside diameter flask; the larger, in. flask. The combination electric are melting furnace and pressure cast- ing unit embodied the machine developed and patented the Aus- tenal Laboratories, Inc., New York, and used this company for casting turbosupercharger buckets (Fig. 21). This type melter and caster combina- tion has not been made available, this date, item standard equipment. Casting Crucibles The substance melted and the temperature reached determine the type material which the cru- cible should consist. Non-conducting crucibles are made such refractory materials alumina, magnesia, silica, zirconia, etc., which contain car- bon. They not absorb energy from the electromagnetic field created with- the induetion coil that they are heated only through contact with the metal charge. Crucibles made from electrically conductive materials such carbon, graphite, platinum, molybdenum, absorb most the high frequency energy and the charge heated pri- marily thermal conduction. The and graphite crucibles are usually chosen for melting non-fer- rous metals alloys which not absorb carbon are detrimentally affected it. The maximum operating tempera- PYROMETER—shows temperature of molter meta! “ON AND OFF” SWITCH WINDING ARM THE IRON November 1944—57 ction vhich illus- For fur- sup- nched sizes ‘ately with a | 4 ¥ Pressure connection (a, Ammeter Input contro/ Switch US. Patent No. tures for which crucibles various types are suitable are given the table below: Deg. Material Graphite Quartz 3632 Zirconia...... The types crucible recommended for certain metals, the melting points and the specific weights these metals are given Table the data for which has been supplied the Ecco High Frequency Corp. Crucibles various forms and shapes are used centrifugal casting machines, some which are illustrated Fig. 22. Casting Machines The casting the molten metal into the cavity the hot investment can accomplished pressure cen- trifugally. the time this writ- ing, information available stand- ard commercial equipment for casting has been equipment the cen- trifugal type (with the exception the Austenal pressure caster already noted). compact motor driven centrifugal machine suitable for small quantity work offered Thomas Dee Co., 1900 West Kenzie Street, Chicago 22. The capacity this standard machine oz. and 58—THE IRON AGE, November 1944 LEFT the patented Aus- tenal casting machine. The are pressure packed where the carbons pass through maintain the air pressure when the melt poured. This done tilting the crucible down- RIGHT Samples ceramic cruci- bles Alexander Saunders Co., New York, for use cen- trifugal casting ma- chine. Note the in- ner struction about the orifice. illustrated Fig. 23. large arm that will accommodate larger cru- cible permitting casting oz. available special order. The machine constructed that two castings can made the same time. The centrifugal force exerted the machine has been calculated approximately times gravity. Sev- eral flasks, ranging size from in. diameter and in. length, in. and are supplied. The Dee company sup- plies patented crucible that claimed keep the metal clean and free from oxidation. Each can used for number melts and are available Carborundum, graphite and for casting platinum. Crucibles may heated small « he gas fired furnace that located close the machine. Although the ma- chine was originally designed for working castings gold and silver being used today for ferrous and nen-ferrous industrial castings. The weight the machine complete lb. and can operated 110 220 volt a.c. The dimensions are in. The Ecco High Frequency Corp., North Bergen, J., present making single flask and 4-flask centrifugal casting machine. The Ecco Model machine, Fig. 24, suited for the economical production dense precision castings any metal, particularly steel and other high melting point alloys. This unit Motor driven 2-flask cen- trifugal casting ma- chine manufactured the position the cru- the flasks which are retained the re- volving arm spring straps. | | — F close ma- for silver and The 220 esent -flask The 24, iction any other unit flask 24— Showing the pivot arm mounting crucible Ecco single flask centrifugal casting machine. (Flask molds ranging size from in. diameter, and from in. length. The rotating assembly driven 3-phase high torque ball bearing motor through variable speed drive which may varied pro- gressively from 260 520 r.p.m. means speed selector wheel, per- mitting straight line control the centrifugal force developed. Properly dimensioned holders are provided secure the investment flask mold position. The injector funnel slides along the arm which automatically positions itself for the various mold lengths. Accurate bal- ance obtained sliding counter- weight and the pivoted arm mounting, which locked during operation. Sequence operation consists placing the preheated investment flask mold into its holder, pouring the metal into the preheated injector funnel and pressing the switch. The metal discharged un- der pressure, centrifugal force, into the mold. The Ecco Model centrifugal casting machine, Fig. 25, accommo- dates four flask molds ranging size from in. diameter, and from in. length. This unit was developed primarily for non- ferrous metals, although many fer- rous castings are also being success- fully produced with this model. disk with suitable mold holders ‘and refractory lined dis- tributor mounted vertical steel shaft which revolves ings. The rotating assembly housed ruggedly constructed welded steel drum and angle iron frame pro- tected cover mounted hinges. The speed the mold disk can varied between 260 520 r.p.m. Sequence operation consists placing preheated metal distributor into the guide the center the disk clamping the investment flask molds the holders and closing the cover. The motor switch closed and the metal poured through preheated funnel into the casting ma- chine. Ecco developing automatical- controlled 2-station machine, which setup comprising one converter and two centrifugal casting machines that the charge can prepared IG. 25—Ecco 4-flask centrifugal cast- ing machine operated hp. motor. Motor not shown base. Cut-away view Model machine made the Centrifugal Casting Machine Co., showing flasks with investment cavities receive metal cast from ce- ramic pouring block. Note that flasks fit carriers welded fixture table. one machine while the charge the ether being heated, thus utilizing the capacity the machine fully possible. vertical centrifugal casting ma- chine which can used produce wide range sizes castings and which can accommodate molds height, the Model machine built the Centrifugal Casting Machine Co., Tulsa, Okla. grated single base that can readily moved unit (Fig. 26). For permanent installation the ma- chine may bolted the foundation through holes provided the base. The speed rotation this machine can adjusted using the proper set sheaves suit the particular size casting being produced. guard, adjustable height, protects the workman from spattering metal. may noted that the fixture which fits onto the machine accom- modates four flasks, with ceramic center pouring block. operation the machine brought the de- sired spinning speed and the metal poured into the central pouring block, which has four small orifices which equally distribute the metal each the four molds. Each mold, course, would contain multiplicity mold cavities make number castings. The design the pouring block such that any slag which poured with the metal would float and thus into the mold last and not actually into the casting cav- ities. Using this type equipment, very high rates production can obtained. The company manufactures the fixtures for flasks four dif- ferent sizes, and in. diam- eter. Flasks made from No. gage stainless steel are available the foregoing diameters, and lengths in. THE IRON AGE, November - «4 fet ° Motor cen- ps. 3 an One the drawbacks the use steels for highly stressed machine parts has been the lack adequate data their fatigue resistance. Described herein are the tests made 8949, 8744 and 9445 steels compared SAE 4340. Endurance limit ratings are given these steels for various degrees stress concen- tration, experience avail- however, many where was found ance highly stressed machine use some National Emer- made from SAE 4340 steel (NE) steel replace the use quenched and tempered condition. SAE 4340. High static and fatigue strength practically all cases the design properties combined with good ductil- member subjected stress re- ity and deep hardenability service and therefore ade- istics has made the selection this quate fatigue resistance must pro- material especially attractive for de- vided any steel substituted for IG. i—Seven designs the shafts investigated. Designs and have fillets with radii 9/32 and 3/32 in. respectively. Designs and have circumferential circular notches with radii equal those the fillets. 4 60—THE IRON AGE, November 1944 ee such data relative the fatigue re- sistance various steels. For this reason the fatigue strength properties 8949, 8744, and 9445 were investigated comparison with SAE 4340 using test sections larger than usual. The fatigue specimens used these tests were in. diameter the test section instead the usual in. diameter employed the conventional Moore rotating beam specimen. Objection data obtained such small samples not entirely confined the size the cross-section but also the shape the specimen. The conventional small fatigue specimen has notches stress raisers and represents what usually termed plain specimen; the surface contour longitudinal cross section formed radius about times the specimen diameter. This shape one seldom attained actual design members and the value the fatigue resistance obtained may termed “ideal” that the value too high. Small fatigue specimens are sometimes made with circumferen- tial V-notch having relatively radius bottom the notch. Such shape represents high factor stress concentration which leads toward value minimum fatigue resistance for any steel investigated. While some design members may actu- ally have localized stresses approach- ing the severity simulated such notch, may generally avoided and certainly considered poor de- sign. Specimens Simulate Good Design Somewhere between these two ex- treme specimen above lies region which simulates good design practice. this region that knowledge the fatigue resistance most value the selection steels and heat treatments for properly shaped design members. For this reason the fatigue strength was determined for seven differently shaped specimens, shown Fig. each four different steels. These seven designs may divided into two general classifications. One group incorporated fillet the test section and Fillet radii this group are 9%, 9/32 and 3/32 in. The second | | re- this ties 445 vith ger the the the lata not the the out ter. alue may are ren- mall ctor 2ads igue ach- ided de- ign ex- ates this igue the ents ngth ntly hese two roup are cond LD 2 6 curves the four steels investigated. ROCKWELL group, identified designs and has circumferential circular notches with equal the fillet radii. All designs shafts had head pressed one end, with the test section lo- cated least one diameter from the face the hub, shown for design Fig. A lige pe Structure fatigue test specimens taken near the surface 1000 diameters. All samples were oil quenched from deg. into full oil spray and tem- pered for hr. give Brinell hard- ness number 302 Above left: SAE 4340 tempered 1100 deg. Above right: 8949 tem- pered 1075 deg. Below left: 8744 tempered 1025 deg. Below right: 9445 tem- pered 1025 deg. i2 14 16 is 20 22 24 26 FROM QUENCHED END SPECIMEN, SIXTEENTHS INCH, The head was bolted rotating spindle and cantilever load applied the opposite end the shaft during the fatigue test. All specimens were taken from the same heat steel for which the chemical analysis given Table The 8744 and 8949 were both open hearth heats while 9445 and SAE 4340 were electric furnace heats. All heats were cast 21-in. diameter inverted hot top molds; ingot weight was about 6000 Specimens were taken from Bes J 35 4 THE IRON AGE, November in. diameter hot rolled rounds proc- essed from these ingots. Four samples from each heat were used for non-metallic rating; all heats wer