The Iron Age 1933-11-30: Vol 132 Iss 22

“ ” NINTH YEAR OF SERVICE TO THE METAL WORKING INDUSTRY Dee CONTENTS INDEX PAGE 9 E IRON AGE UCTION -:- MANAGEMENT NOVEMBER 30, 1933 PROCESSES -:- NEWS oe xs a A met ae ry Fie Alea ; i ay a ee, ee pein ern . kp | TO BETTER PRODUCTS ees Manufacturers faced with the problem of designing new products or re- designing old ones should investigate ENDURO. Here’s a metal with countless pos- sibilities. Here’s a metal that is cor- rosion-resistant and heat-resistant. Here’s a metal that is always the same, that never changes and upon which atmosphere, salt water, fruit juices and most chemicals have no effect. Here’s a metal that to all practical intents and purposes is everlasting. There is a place for one of the many grades of ENDURO, Republic’s Perfected Stainless and Heat-Resis- tant Steels, in the products you will be marketing in 1934. EIN TRASL ALLOY DIVISION +-+ MASSILLOM, OHIO BLIC STEEL CORPORATION BR A we , Ont LAL OFFICES NRF 7 YOUNGSTOWN, OnIO Licensed under Chemical Foundation Patents Nos. 1316817 and 1339378. THE IRON AGE...NOVEMSER 30, 1933 Page 2 SHIELDED ARC WELDING IMPROVES EDWARD VALVES... Gigi “Here, Lad, is where they fuse extra quality, extra strength and extra safety into Edward valves. It’s done by welding with a shielded arc. “They tell me that thousands of Edward valves of various types have been pro- duced by this process. Especially forged steel valves. Under extreme service conditions, they stood up successfully.” What's NEW in Welding! %, procedu 434 $ o= r te f r r 0n , 5 5 WwW ite ° desc ip ° poge>: . and high capacity. Those are two of the essentials of production os course Edward valves stand up. They're using Lincoln Abe ‘Shield-Arc’ welders and that means a uniform welding current line welding. “The ‘Shield-Arc’ provides all the other essentials too. That’s why the super likes it as well as the welder operator. And why the cost accountant likes it as well as the super. “For the same reason Lincoln is able to make this 3-way guarantee: i. 2. J “Whether it’s valves or jigs, machine tools or pipe, you can take ‘Fleetweld’ electrodes and a ‘Shield-Arc’ welder and have a pair that says ‘We do our part.’ Proof is yours for the asking.” More weld metal deposit per K. W. H. Faster welding per K. W. H. Lower cost per unit of welding—the unit being per lineal foot of weld, or per pound of weld metal, or per hour of welding. LINCOLN THE LINCOLN ELECTRIC COMPANY, CLEVELAND, OHIO Largest Manufacturers of Arc Welding Equipment in the World | RON AGE, published every Thursday by the TRON AGE PUBLISHING CO. Publication Office: N. W. Cor P Executive Offices: 239 W : 9th St., New York, N March 3, 1879. $6.00 a year in U. S., Canada $8.50 s _Y., U S. A. Entered as s¢ 00 Foreign $12 Vol. 132, Ne or. Chestnut & 56th Sts., cond class matter at the Post Office at Philadelphia under Act | J. H. VAN DEVENTER G. L. LACHER WwW. W. MACON T. H. GERKEN | Editor Managing Editor Consulting Editor News Editor F. J. WINTERS | .. THE IRON AGE .. G. EXRNSTROM, JR BURNHAM FINNEY F. L. PRBNTISS R. A. aa A. I. Finpizy ae mids R. G. McIntTosH Cleveland Chicago Editor Emeritus Washington Cincinnati _= 5 a amniepinnennieneiianiininaaniinemmndiiin | R Contents The Little Pig and the Three Bad Wolves Making Ring Gears in Chevrolet Plant Brass Pressure Castings Produced Economically Fuel Economy of Blast Furnace Operation | Planing Versus Milling Symposium | Rail Buying in Two Depressions New Materials and Processes . | Chromium in Malleable Iron “" | New Equipment ‘oln News = Personals and Obituaries ” a Washington News hy | Automotive Industry | ast ee eee eet Construction and Equipment Buying eC: Products Advertised Index to Advertisers a a & THE IRON AGE PUBLISHING COMPANY I FRANK, President G./H. GRIFFITHS, Secretary C. S. BAUR, General Advertisi Manaye - PUBLICATION OFFICE: N. W. Corner Chestnut and 56th Sts., Philadelphia, Pa. EXECUTIVE OFFICES: 239 West 39th St., New York, N. Y., U.S. A. l’ublished every rhursday Member, Audit Bureau of Circulations 1DVERTISING STAFF Member, Associated Business Papers Emerson Findley, 311 Union Bldg., Clevelan B. L. Herman, 675 Delaware Ave., Buffalo, N. Y. H. K. Hottenstein, 802 Otis Bldg., Chicago Subscription Price Peirce Lewis, 7338 Woodward Ave., Detroit United States and Possessions, Mexico, Cuba, $6.00 Charles Lundberg, 45 Kent Rd., Upper Darby, Canada, $8.50, including duty; Foreign, $12.00 a Del. Co., Pa Cc. H. Ober, 239 West 39th St., New York W. B. Robinson, 428 Park Bidg., Pittsburgh W. C. Sweetser, 239 West 39th St., New York Cable Address, ‘‘Ironage, N. Y."’ D. C. Warren, P. O. Box 81, Hartford, Conn. year. Single Copy 25 Cents R. E. MILLER Machinery Editor GERARD FRazar ll 12 16 20 22 24 27 29 30 35 37 38 45 E 98 SEVENTY-NINTH YEAR OF SERVICE TO THE METAL WORKING INDUSTRY THE IRCN AGE...NOVEMBER 30, 1933 Page 10 2 EE ph yur My, fd Y A, 2 \ a \ SS > ae -oh . | aaa Te ead eed —— 4 * SN 4 _— ~~ ss | X ‘ oe ei . | Pe it Beep itty we x lau setup 7 . " et sys co Tar ttt sf ae — ——“4 SS See Making Immediate Steel c- takes more than fast trucks and speed- ing trains to give you Immediate Steel. Stocks the largest and most diversified in the country are strategically placed to quickly serve the principal industrial areas. Special methods for handling and dispatching, de- Immediate Steel, the product of the ten ; Ryerson Plants, is ready to use. It includes all shapes, sizes and kinds of steel as well as allied products. You can count on it for both emergency and regular production require- velopments of more than ninety years of steel service, assure dependable, accurate shipment in record time. ments, for no order is too large for immedi- ate shipment nor too small for personal at- tention. Write for the Ryerson Stock List—**Key” to these stocks of steel JOSEPH T. RYERSON & SON, INC.—Plants at: Chicago, Milwaukee, St. Louis, Cincinnati, Detroit, Cleveland, Buffalo, Boston, Philadelphia, Jersey City RYERSON ze Beams and Heavy Stracturels ‘ Large stociks—all shapes, including special wige lenge sections “ Rails, Splices, Spikers, Bolts, Etc. iS New rails with all asccessones-- stocked for immediate shipment Pletes ae Standerd steel plates, high carbon, MN! firebox steel, Armco lrom and dia- mond pattern. Stocks that You" Can Depend on to Meet Every Steel Requirement Both structural and ber sizes in all” G stenderd sections, siso galvenized - _ Hoops and Bands _» Bers—A\ll Shapes and Sizes » 4 Cold Finished Steel Bars mn mts Extra Wide Cold Finished Flats Gu | Bands, both ‘plain end galvanized, & xm Round flets, ; ~ p2 Filets, rounds, squeres and hexagons in . ° Send hoops in both coils and streight [emer lounds, squares, , hexagons, ak weriaus enatyses. Accuracy, streight- Widths up to 12 inches in 4” to 2” Ess | lengths ere cerried in stock te a halt-owals, half-rounds, etc. Poe ness and hinish assured. ‘ a im thicknesses are carried in stock. WA ... THE IRON AGE ... NOVEMBER 30, 1933 ESTABLISHED 1855 Vol. 132, No. 22 The Little Pig and the Three Bad Wolves HAT is keeping this little pig in- doors? He believes that he sees three bad wolves prowling about his house and is afraid of them. So he has bolted the door and hidden his pocketbook under the bed. Perhaps these wolves are imaginary. Perhaps they haven’t the long ears and big teeth that he thinks they have. But until some one convinces him that they mean no harm to him, he is going to stay in his little brick house. The little pig, of course, represents the private investor, who normally provides the funds for the buying of capital goods. Uncle Sam wants to get the little pig out of the house and to have him bring his pocketbook out with him. For until he does come out, Uncle Sam will be about the only real buyer, directly or in- directly, of capital goods. The best and the quickest way for Uncle Sam to get the little pig out and his pocketbook open is to convince him that these animals are not wolves but friendly little pets that will do him no harm. If that is an impossible under- taking, he should load his gun and shoot them. Chevrolet Makes aa ~ ee - tes Gears are carburized at the rate of 140 an hour in four-track, pusher-type electric furnaces. Above is shown the discharge end with a carburizing pot containing nine gears which has just come out of the furnace. a a & HE Chevrolet Motor Co. is clos- Tine its third consecutive year as leader in volume of sales in the automobile industry. It has been able to maintain its top position by offer- ing a car of quality workmanship and material at a low price. Without economical production methods, this low selling price would not have been possible, and economical production in turn could not have been achieved without modern shop processes and equipment. To find outstanding examples of efficient methods employed by the Chevrolet company in the manufac- ture of its car, one might turn to any of its several plants. The production of ring gears and pinions for pas- senger cars at the gear and axle plant in Detroit is one of the most interest- ing examples. The department there, devoted to gear cutting and machin- ing, is the largest department of its kind in the world and its methods are worthy of close examination. Because of the nature of the work which they perform, gears constitute a product the manufacturing treat- 12—The Iron Age, November 30, 1933 ment of which must be minutely scru- tinized and rigidly controlled from operation to operation. Tolerances are thought of in terms of thousandths and ten-thousandths of an inch, and the slightest distortion of the gear teeth may cause trouble in the fin- ished car. Realizing this fact, Chevro- let’s production officials maintain a constant watch over the gear depart- ment to make sure that the quality of the work is uniformly high and materials in process flow freely at all times. It is a part of the daily production practice to put try-out gears from every working shift through rigid tests and then over the assembly line to see that the bearing positions are correct and quietness has been at- tained. The time when the work ap- parently is progressing at the smooth- est rate is the time when the closest vigilance is kept. This vigilance is necessary because there is no way to forecast in which direction a job may go—toward perfection or toward trouble. If it is toward trouble as it will infrequently be even in the ing Gears in W By BURNHAM FINNEY Detroit Editor, The lron Age HE Chevrolet Motor Co. uses rigidly controlled precision methods in making passenger car ring gears at its Detroit plant. The heat-treating, machining and in- spection processes are herewith described. This is the first of a series of exclusive articles outlin- ing the manufacturing practices of the Chevrolet company at its various plants. — oe ae best organization, the operator is al- most instantly aware of what has happened and moves rapidly to cor- rect the defect. Ring gears are made of alloy steel. From the forge shop the blanks go to an oil-fired normalizing furnace where they remain for six hours. The furnace is divided into two long sec- tions paralleling each other. Blanks go in one section on an overhead con- veyor from which they are suspended, travel its length and are switched over to the other section, moving through it and emerging at a point adjoining the loading position. Blanks are in each section about three hours. The overhead conveyors are arranged in four rows, with each vertical car- rier capable of taking five blanks. Blanks pass through a hot zone for 40 min. The normalizing operation removes the strains set up by forg- ing and makes the blank more ma- chinable. After normalizing, the blank has a Brinell hardness of 4.6 to 4.7. The front and back face of the blank is rough turned on a Six- spl chi ani to tio bre pe : in World's Largest Gear Cutting Plant spindle Mult-au-matic chucking ma- chine having four operating stations and two loading stations. From 1/16 to 1/32 in. is removed by this opera- tion. The hole of the gear then is broached on a vertical machine equip- ped with a special fixture. Rivet holes are drilled in the gear on a double-head vertical drilling ma- chine, each head of which has 12 spindles. Thus the machine drills 24 holes simultaneously, 12 in each of two gears. There are four stations, two of which are being loaded by the operator while the other two are in use. From the drill the gear blank moves to a special machine which stamps on the gear part number, the gear ratio, the month, the year and the Chevrolet trade-mark. After the back face of the gear is ground to within 0.002 in., the out- side diameter of the blank and the tooth face are finish turned and counterbored on a six-station Mult-au- matic chucking machine on which two consecutive stations do the same work. This makes the machine the equivalent of two machines. For this job special tools have been welded on to standard tool blocks. Special chucks are used to hold the work. In the base of the chuck is a spring controlling three fingers which hold the blank by being inserted in the rivet holes. The operator moves these fingers in and out by means of a hand lever. At this point the blanks are placed in pan-type conveyors and taken to an inspection station where they are tested for runout, outside diameter, bore hole and face angle. The toler- ance for the face angle is 0.005 in., for the outside diameter 0.004 in., and for the bore hole 0.0015 in. The back face is held to 0.002 in. on a surface plate. Having passed inspection, the blanks are carried to the gear cutting machines. The ring gear used on the Chevrolet passenger car is .an all- spiral bevel gear consisting of 37 teeth with a mating pinion of nine teeth. The pitch of the gear teeth diameter is 3.947 in., and the spiral angle is 38 deg. 4 min. The pressure angle is 14% deg. Teeth of gears are rough cut at the rate of five gears an hour on a standard gear cutting machine and are finish cut on 15-in. spiral gear cutting machines, the finishing time being 24 min. per gear. Speeds and te ss me feeds of these machines are figured to give the maximum results for the type of steel used and the pitch of the gear. After the finishing opera- tion, one gear from each machine twice during each 7%-hr. shift is tested for bearing position, size and finish. After roughing, gears are tested for proper tooth depth. The roughing operation leaves about 0.018 in. of stock on each side of the teeth for the finishing cut. Between the two gear cutting op- erations, the back and front angles of the gear teeth are chamfered at a 45-deg. angle on a gear chamfering machine. After being finish machined, gears are taken on an overhead con- veyor through a washing machine where they are cleaned with a G. M. C. resin compound. Then they move to a gear testing machine and are rolled 100 per cent for size, runout, finish and position of bearings.’ From the testing machine gears are put into large metal containers and trans- ported on electric trucks to the heat- treating department to be hardened. a After being carburized, gears are quenched in an oil quenching machine, the gear being held down in a die for 57 seconds. This method maintains a flat back on the gear and uniformity in the bore for roundness. The Iron Age, November 30, 1933—13 Nine gears are packed in a carbur izing pot in a special compound and the pot is lifted by crane to the loading end of an electric pusher-type car burizing furnace. This furnace has four tracks, the hardening time be- ing 9 hr. The temperature in the carburizing zone is 1650 to 1680 deg ’. One hundred and forty gears an hour are carburized to a case depth of 0.040 to 0.050 in. At the discharge end of the furnace the packed carburizing pots are dumped by means of an overhead crane and the gears are quenched in an oil quenching machine, the gear being held down in a die for 57 sec. This method of quenching is for th purpose of maintaining a flat back on the gear and uniformity in the bor for roundness. Bores are kept with Iron Age, November 30, 1933 A special chuck is used to hold the gear blank in place on a Mult-au-matic machine for finish turning and counterboring the outside diameter of the blank and the tooth face. In the base of the chuck is a spring con trolling three fingers which are inserted in the rivet holes to hold the blank. The operato: moves the fingers in and out by means of a hand lever. After being finish machined, gears are rolled 100 per cent for size, runout, finish and position of bearings. vvyv Gear teeth are rough cut at the rate of five gears an hour on a standard bevel gear cutting machine. in limits from zero to 0.003 in. out of round and the back of the gear is held to a warpage of not over 0.003 in. thickness. From the quenching machines the gears move on an overhead conveyor through a spraying and washing with G. M. C. resin cleaner:compound for degreasing purposes. Thence they go through an overhead draw furnace the temperature of which is 325 deg. F. This furnace is designed so as to occupy a minimum of space, the con- veyor loaded with gears making an S To remove any rough ness on the profile of pinion teeth, pinions prior to har- dening are burnished on a spiral bevel pinion burnishing machine. A soft pinion is run in mesh with a hardened mat- ing gear, being given a slight motion lengthwise of the face. In the photo- graph the metal guard has been lowered. turn inside the furnace. From the time when they are loaded on the con- veyor after being oil- quenched until they are removed after the drawing operation, gears are en route 1% hr. Gears then are brushed on a wire brush wheel to remove the dirt and scale, are file inspected and are tested for out of roundness. The Brinell hardness of the finished gear is 3.70 to 3.90. Following heat treatment the out- side diameter of the gears is ground, locating from the bore, after which the bore is ground, locating from the outside diameter. Gears are sent through a wash tank to remove grease and to an inspection bench, where the bores are inspected for size and the backs for flatness. They are hung on an overhead conveyor and carried to a gear testing machine and then mated with pinions on correct cones. The gears again are hung on the conveyor, going to an inspector who examines them for position of bearings and out of roundness. If they are approved the gear and pinion are tagged with duplicate numbers, the gear moving down one line and the pinion down another until they finally are brought together in as- sembled form. Pinions after being finish cut, are put through a burnishing operation on a spiral bevel pinion burnishing ma- chine. This is accomplished by run- ning a soft pinion in mesh with a hardened mating gear to smooth out any roughness on the profile of the pinion tooth. Instead of the rocking motion formerly used in burnishing, the teeth are given a slight motion lengthwise of the face. That is, the pinion drives the gear and as the two rotate, the position of the gear is changed continuously and auto- matically to effect a combined hori- zontal and vertical movement relative to the pinion. As the position of the gear is changed, the pinion, which is held in mesh with a spring, moves in and out with the gear. This results in an in and out movement of the pinion with reference to the gear axis. The pinion head is equipped with hardened rollers which ride on two hardened steel guides fastened to the top of the frame, allowing the head to move freely. It is adjusted hori- zontally with a hand wheel and adjust- ing screw. The driven spindle has both hand and backlash brakes, the former for use when setting up the work or for checking the tooth bear- ing before or after burnishing, and the latter to maintain an even load during the burnishing operation. Spindles are mounted on matched The Iron Age, November 30, 1933—15 ball bearings which are preloaded to eliminate radial and axial deflection. The operation is watched closely, with a pinion taken direct from the ma- chine for inspection every 10 to 15 min. This precaution is taken to avoid the burnishing gear wearing down and not giving the proper smoothness to the pinions. Production on this ma- chine is about 200 pinions per hour. After being burnished, pinions are rolled 100 per cent for the position of the bearing, noise, size and errors by operators. They then go through heat treatment and follow the same finishing process as ring gears. In an opinion handed down by Judge Marcus B. Campbell in the United States District Court for the eastern district of New York in the case of Hiram A. Farrand, Inc., and the Stan- ley Works, New Britain, Conn., against a prominent chain store, the four patents on coilable rules of Hiram A. Farrand were sustained. The defendants were obliged to cease infringing and to deliver up for de- struction all infringing rules which they now have on hand and to pay costs of suit. Hiram A. Farrand, Inc., owns rights in seven United States patents and has several patent appli- cations pending. The Stanley Works is licensed under above patents and patent applications and also has sev- eral patent applications pending. No foreign manufacturer has any license under any of said patents or applica- tions. These pressure cast products illustrate the diversity of the process. successful brass pressure die cast- ing process devised by Joseph Polak in Prague, Czechoslovakia, led to an investigation of the possibility of introducing this method of manu- facturing brass parts in the United States, where no such method existed at that time. To fully understand what most engineers and manufactur- ers in this country thought of die casting brass in 1930, one need only refer to an article by J. B. Nealey which appeared in December, 1929. In that he said, “It is, indeed, deplor- able that the most useful non-ferrous alloys, the brasses, cannot be handled by this (die-casting), the most ef- fective and economical method of forming.” Pisccessfut br rumors in 1930 of a Machines Placed in Operation The results of the investigation of the Polak process were so encourag- ing that three machines were pur- chased and placed in operation in this country. Soon afterward two other installations were made and in each case the operating company was a manufacturer of brass forgings. This is one of the significant features and it is from the point of view of com- petition between brass pressure cast- 16—The Iron Age, November 30, 1933 ings and brass forgings that much of the following data is presented. The Polak Machine The Polak machine operates with hydraulic pressures of between 3000 and 6000 lb. per sq. in., and it was this feature that made the process prac- tical because it made possible for the first time lower casting temperatures. The brass is forced into the die cavi- ties in a semi-molten or plastic con- dition rather than in the customary molten state. This allows the metal to be worked at a temperature sev- eral hundred degrees lower than would be the case if the machine were gravity fed. The lower working tem- perature makes the process economical because of the greater life obtained from the expensive dies. In actual practice the temperature of the brass is 1575 deg. F. (860 deg. C.) Three sizes of machine are in operation. The small one, occupying 6 ft. by 5 ft. floor space and standing 6 ft. high, is shown on opposite page. On this machine with single impres- sion dies, it is possible to produce sev- eral hundred pieces an hour. An eigh- teen-month study gives an average production of 136 pieces per hr. Speed M fore the author of this article would describe the process and label it an economic addition to the metal fabricating arts. The new technique, the new types of die casting machines, and the new castings themselves are here By WILLIAM W. SEIG Metallurgist, Titan Metal Mfg. Co. a2 ae ORE than a million brass pres- sure castings were made be- described. vrvyv of operation will depend on how com- plex the design of the die is and whether there are cores to pull. The small machine will cast pieces weigh- ing 10% oz. The next size machine casts parts up to 1 lb. 5 oz., while a still larger machine will cast parts weighing 11 lb. The small machine has a normal water consumption of \% gal. per operation. This is required for the closing and opening of the dies by means of an auxiliary cylinder of small diameter and for the locking pressure which is not applied until the die is closed, at which time a valve is opened allowing the water to enter the large cylinder, thus multiplying the actual pressure exerted upon the die. The Die-casting Cycle When the die is closed, the brass in a plastic or pasty condition, as stated, is ladled into the compression cham- ber where the sudden high pressure forces it into the die cavity. Imme- diately thereafter the remnant of metal is ejected. On opposite page is shown press operator ladling brass into the compression chamber. In one of the pans are the finished parts, and in the other may be seen the remnant. Simultaneous with the ejection of the Brass Pressure asi remna drauli pulled cores % from means cycle ed on the n three- a wool sq. in Th any oil, © the cl a lad furné the ¢ tice i but foun tric | elect belov sure This arran ing f ing f oper: erate semi from into chan reCastings Are remnant the die is opened by hy- draulie retroaction, all the cores being pulled automatically. As soon as the cores are pulled, the casting is ejected from the moving part of the die by means of ejecting pins. The complete cycle is diagrammatically explain- ed on page 19. Power is supplied to the machines by one Smith A-Type three-plunger pump which operates at a working pressure of 1800 lb. per sq. in, Composition of Castings The brass may be melted down in any of the common furnaces, gas, oil, or electrically controlled. After the charge is melted, it is poured into a ladle and transferred to a holding furnace from which it is ladled into the casting machine. European prac- tice is to use oil fired holding furnaces, but engineers in this country have found automatically controlled elec- tric furnaces highly satisfactory. An electric holding furnace is shown below. Numerous analyses of pres- sure castings made in various parts 7 This shows a typical arrangement of hold- ing furnace and cast- ing machine for hand operation. The op- erator ladles the semi - molten metal from the _ furnace into the compression chamber of the ma- chine. Produced E vW WwW vW of Europe show considerable varia- tion. PRACTICE 62.00 EUROPEAN 58.0 cent to cent to cent to 0 cent to eent to Copper per Lead 0.25 per 2.00 Iron 0.0 Tin Zin per 0.0 $1.75 per per 7 1.25 34.04 100.00 100.00 FOUND BEST BY AUTHOR 60.00 per cent Copper Lead 0.75 per cent Tin Zine 0.50 per cent 38.75 per cent Considerable success has been ex- perienced in casting a white metal alloy containing 16 per cent nickel and known by the trade name of Tinicosil. This alloy has a distinct white color, is highly resistant to corrosion, and has a tensile strength of 90,000 lb. per sq. in. The of brass fracture a_ typical pressure casting is fine grained as shown in the accompanying photomi- crographs taken at a magnification of 100 and 1000 diameters and which are compared with similar photomicro- conomically graphs of typical brass forgings and sand castings. Test bars dimensions for zine die cast test bars and were sent to the Pennsylvania State College where they were tested by Frank Gordon Benford. were cast to A.S.T.M. The re- sults of these tests are as follows: PHYSICAL Elastic Limit per 2c ehs. : ef @gas = 2s o5Sas Ags 1 60,000 37,750 3 60,000 38,000 } 57,200 35,750 6 58,900 36,250 i 58,100 36,000 8 58,100 35,750 12 56,700 35,250 14 57,900 37,000 16 58,700 36,000 Avge. 58,400 36,417 Rockwell hardness 90 90 Per Cent to ~ Red. In Area — a —) o w - o ~- 6.7 6.8 8.5 7.6 readings Per Cent PROPERTIES OF BRASS PRESSURE CAST TEST BARS Elongation In 2 In. ee es) AAam ARQ DH on, 6.2 were taken using B Scale, 1/16 in. ball and The Iron Age, November 30, 1933—17 100 kilogram load. Surface readings were taken on the cylindrical surface of the rods and sectional readings were taken on a flat section cut about 1% in. from the end of the test bar before testing. AN Hardness Reading Bar No At Surface At Cross Section ] 44 ; 42 3 it 17 46 17 47 $5 Average 45.2 The divergence in hardness is prob ably due to the more rapid rate at which the surface cooled. Comparative physical properties of brass made by various methods are shown below. Die Life The dies for pressure casting brass are subject to extreme heat at high pressure and offer the alloy steel manufacturer a practically unexplored field to work in. At the present time semi-high speed steels are being used with considerable success, but are not all that could be desired by any means. The trouble is not with the breaking of dies, which does not seem to occur, but rather is due to heat checks which are quite prevalent. Stainless steels are being used experimentally, as well as austenitic steel containing high nickel and high chromium, but in gen- eral most of the dies are being made from steel within the following com- position range: Brass Forging (Dark Particles Are Lead) Carbon 0.30 to 0.50 per cent Silicon 0.20 to 0.60 Manganess 0.20 to 0.50 Chromium 1.00 to 3.00 Vanadium 0.20 to 1,00 Tungsten 8.00 to 14.00 The greatest life so far experienced with die steel is 121,000 pressure cast- ings made from a one-impression die. ; ns : Brass Sand Casting Brass Sand Casting The average life per die impression ; ; d \ is approximately 30,000 pressure cast- _ Comparison of grain structure of pressure cast, forged, and sand cast samp es. ings. Naturally, the life of the die Magnification of photomicrographs in left column, 100 diameters; right column, 1000 diameters. will depend a great deal on the shape ° ; of the part and on proper gating. ings and should not be used where sections and seldom ever form in light . ; extraordinary water, gas, or air pres- sections. Porosity sure is to be used. This tendency to It has been claimed that this Brass pressure castings are subject form blowholes is one of the disad- porosity is caused by the fact that to porosity in the same manner that vantages of the process, but two years’ steel dies are airtight, and this is zinc and aluminum die castings are experience has proven that these blow- partly true. However, sound castings subject to porosity. In this respect holes can be controlled to a large have been produced from gravity cast- they are not as sound as brass forg- extent. They will be found in heavy ing into airtight metal molds. Adolf Butner, factory representative of J. Polak, Prague, describes the forma- tion of these blowholes as follows: “The main reason for the blowholes COMPARATIVE PHYSICAL PROPERTIES OF BRASS %ar J - ; , Tensile ad usa Composition in die castings is the metal stream Lb. per Elong. Pent produced by the use of pressure. The Description Sq.In. In 2In. Surface Sec Cu. Pb. Sn Zn metal shoots in the cavity of the die Sand cast valve stem..... 38,600 22.0 B-25 B-5 75.40 5.40 1.41 Rem similar to the way water is delivered Forged valve stem....... 77,000 41.8 B-70 B-68 58.50 2.20 ... Rem from a fire hose, or in the Pelton wa- Pressure die-cast stem... 60,000 6.6 B-44 B-34 60.10 0.70 0.52 Rem ter turbine. The metal stream part- Hot rolled brass (hard)... 67,500 5.0 ae MY 64.5 0.30 2a Rem ing the cavity in two divisions is re Hot rolled brass (% hard) 52,500 15.0 of aN 64.5 0.30 oan Rem Rested fem, the aalle. of Wie die: Hot rolled brass (% hard) 45,000 27.5 ‘eed sani 64.5 0.30 ‘On Rem whirls in the cavity and traps the air before it can escape from the die. It 18—The Iron Age, November 30, 1933 nt is it is b f \- =v (2 = © happens sometimes that this metal stream comes back to the gate and traps the air before the cavity is filled up. The only way to prevent these air pockets is to prevent this type of flow from developing. This can only be done by proper gating and proper venting.” Experiments carried on by J. D. Grogan, and also by Dix and Keller, on zine and aluminum die castings, proved to them that there were five reasons for the formation of blow- holes and these same reasons largely determine whether or not brass pres- sure castings are porous. They sum- marized the causes of porosity as follows: 1. Insufficient metal 2. Too low temperature 3. Insufficient pressure 1. Too small gate Incorrect venting It is felt that one other cause should be mentioned which can only be controlled from the engineering de- partment in laying out the die, and that is improper gating. The problems of gating and venting must be solved largely by experience. The surface finish is not as good as that obtained from a forging. Brass pressure castings require more finish- ing time prior to plating than forg- ings, but are considerably better than sand castings. In short, the finish on pressure castings lies between sand castings and forgings. The reason for the rough surface is due to heat check- ing of the dies, and a light scale which builds up on the die impressions during the casting process. This roughness will, no doubt, be better controlled as alloy steel manufactur- ers improve their die steels. Economic Status Brass pressure castings are su- perior to brass sand castings for the following reasons: | The surface finish of pressure castings is better than the ‘surface of sand castings. ?.—-Machining tools wear longer without redressing, due to absence of sand in pressure castings. Pressure castings can be produced having sharper outlines and greate! dimensional accuracy than sand cast ngs. Intricate cored parts are readily produced. { The pressure casting process is very well adapted to the production of cast- ings having thin sections (0.060 in minimum) which parts are very ex pensive to cast in the foundry, and which are impractical for forging. They are inherently small grained and have a strong structure, properties which give them a marked superiority over sand castings. In many applications brass forgings have replaced sand castings, and re- placement will continue in many fields with pressure castings replacing both forgings and sand castings. Of course there are applications where forgings will always be used and like- wise there will always be a demand for sand castings. Brass pressure castings will be used where sand castings quality is not good enough and where forging quality is better than the applica- tion demands. Aside from this they will be used where the other processes are not adapted economically for production of various parts. An example of this would be a part having quite heavy and quite light sec- tions which would. give trouble as a sand casting or as a forging. The Polak brass pressure casting pro- cess is well adapted for the production of such parts. Brass pressure castings compared with brass forg- ings bring out the following interest- ing points: A Brass pressure castings can be pro duced with less operations than forg- ings, the various steps in production for both processes being as follows FORGING PRODUCTION Weighing charge 2. Melting charge Casting ingots t. Sawing ingots Heating billets 6. Extruding billets into rods Sawing rods into slugs 8. Heating slugs 9. Forging 10. Trimming flash from forgings PRESSURE CASTING PRODUCTION Weighing charge 2. Melting charge Transferring to holding furnace 1. Casting parts Removing small fins B.—The production of pressure castings results in a defective scrap loss of between 7 and 10 per cent as com pared with 3 to 5 per cent with forgings In sand castings reliable nformation places defective scrap a between 10 and 15 per cent Cc More intricate parts can be readily produced by pressure casting than by forging. Fig. 5 shows a group of pressure castings and illustrates the complexity of parts which it is p ible to produce. The diagram at the : : 3 left is the starting ‘ position and that at the right is the posi- tion after the cast- ing cycle has been completed. 5 vvyv 6 if ST =s yee ZA VALLES Ay ke ja > o> Gates of 6, 8, 10 or more pieces are successfully pres- sure cast. D There is very little difference between the rate of machining brass pressuré castings and brass forgings. E.—As previously noted, the forging sur- face is better than the pressure cast- ing surface. F.—Brass pressure castings and brass forgings both show a very fine struc- ture, but the forging is the stronger of the two, and is the more reliable material from an engineering view- point. G Pressure castings are produced closer to size than forgings and less draft is needed, resulting in less material to remove in second operations, such as reaming to s1Ze. H Fig. 6 shows six pressure cast nuts attached to the gate A study of the scrap produced in making this part as a pressure casting and as a forg- ing is quite interesting, keeping in mind the fact that only half as many operations are necessary to produce the nuts. Finished forgings per 1000 Ib. charged in furnaces 490 lb Finished pressure castings per 1000 Ib. charged in PPS: 6s aceon eo 475 Ib. It is possible to cast threads on brass pressure castings and it is, also, pos- sible to forge threads on brass pres- sure castings In both instances it is not regarded as practical, due to die difficulties, and the fact that modern machinery is so designed that second operation threading of parts is more economical. A Pi H n HS td , ati) Tes r t 4, fe ao The Iron Age, November 30, 1933—19 URING the last 50 years the D blast furnace has been steadily improved and enlarged physi- cally. More efficient operation gener- ally has resulted. The average fur- nace of today probably has a daily capacity of upward of 500 tons and stacks of more than 1000 tons output are in operation. Still larger units than any now constructed are pro- posed. That the average modern furnace is more economical of fuel than the smaller one of a generation or so ago is admitted without argument. But as hearth diameters and outputs have increased it has been occasionally ob- served that unit fuel consumption in some of the larger stacks has some- times exceeded that of some of the smaller. An understanding of all factors that will lower costs or pre- serve natural resources for future generations is vital to so practical] an art as iron smelting. Comment and speculation on the reason for the fail- ure of some of the larger furnaces to attain the fuel economy of the smaller ones may, therefore, be of interest. Stresses Unit Rate of Gasification That furnaceman_ extraordinary, the late J. E. Johnson, Jr., has stated' that the driving rate is dependent, not so much on the hearth area, as it is on the unit rate of gasification, such as the amount per cubic foot of the combustion zone. He defined the combustion region as the space from the tuyere plane to well toward the top of the bosh. Disregarding the idea of inherent differences in coke combustibility, the unit rate of gasifi- cation is largely governed by the pres- sure of the oxygen supplied by the blast. Johnson’s thought evidently Johnson, J. E., Jr.—Principles, Opera- tion and Products of the Iron Blast Fur- nace, New York, 1918. *Korevaar, A.—Combustion in the Blast Furnace and Gas Producer, London, 1924 *Clements, F.—Blast Furnace Practice, 3 Vols., London, 1929. _*G. St. J. Perrott and S. P. Kinney— Combustion of Coke in Blast Furnace Hearth. Trans. A.I.M.E. Vol. LXIX, p. 543, et seq. Kinney, Royster and Joseph— Iron Blast Furnace Reactions. ow. B Bureau of Mines, 1927. 20—The Iron Age, November 30, 1933 was that if all base conditions, such as volume of voids, character of bur- den, blast, grade and size of coke and so on, were the same, then combus- tion and therefore production should proceed at about the same rate in different furnaces if blown with air at the same rate per unit of volume. Heat Compression Other factors should be considered. Since the entire blast furnace process is not so much one of reduction as it is heat production, quality of heat in the hearth is quite as important as quantity. Korevaar, in his study of the fundamental action of the blast furnace has formulated “The Law of Heat Compression.’”” This is a new theory and while fairly complicated in detail, is easily understandable in a general way. Although it has not been widely discussed or investigated to the extent that it may merit, from the extended references, both as to theoretical and practical phases, its validity is evidently accepted by the author® of the most recent and com- plete treatise on blast furnace prac- tice extant. The theory demonstrates that it is possible to produce by burning fuel at a more intense rate within a given volume or space, such as per cubic foot of combustion zone, a higher tem- perature with a given fuel consump- tion, or what amounts to the same thing, that it is possible to sustain the same temperature with a smaller fuel consumption. By burning a quantity of fuel, F, at a given and constant rate within a closed and in- sulated space, such as the blast fur- nace hearth, some definite tempera- ture, 7’, will be attained. If the fac- tors are so increased that a larger quantity of fuel, F,, is gasified per unit of time, thus liberating more heat in the same space, some higher temperature, 7, will be reached. Radiating and conducting influences are more constant, so a simple ex- pression for the compressed heat effect, proposed by the writer, is: F, T.=TXxX—xXk F By H. A. SPALDING Mining Engineer, Hazard, Ky. k being the reactivity constant of the fuel. Since the rate of combustion is mainly a function of the available oxygen, a furnace on slack or “slack- er” wind, burning less fuel per unit of volume of combustion zone per unit of time would lose the effect of this increased intensity of heat, com- pared with one having a higher com- bustion rate. As the area of a fur- nace varies as D* while the radiating surface varies only as D, D being the hearth diameter, the total loss of heating effect to a large hearth as compared with a smaller one obtain- ing this effect would be enormously large. Moreover, most of this in- creased intensity, or compressed heat effect, is applied above the “critical temperature.” As a certain thermal equilibrium must be maintained, in the final consideration this would mean for the same set of conditions and proportionally lower wind, a greater fuel consumption for the larger unit. On the other hand, when proper conditions obtain to create the com- pressed heat effect, which are mainly ample wind at uniform pressures, since luminosity, conduction and so on also vary as D*, the advantages should be correspondingly greater for the big stack. So long as hearth heat demands are met direct reduc- tion will mean fuel saving by the greatest use for reduction purposes of the CO generated at the tuyeres; the greater the portion of this neces- sary hearth heat met by the com- pressed heat effect the further can Greuner’s Ideal be departed from with consequent fuel economy. Globular Regions at the Tuyeres This does not mean that combus- tion takes place uniformly through- out the hearth and bosh. As a mat- ter of fact conditions are considerably modified. As has been demonstrated by the investigations of the Bureau of Mines and others, gasification does not proceed uniformly throughout the hearth and bosh, but in more or less local and globular shaped regions in front of the tuyeres.* Thus the nec- essary blast volume does not vary so . . « Crux of the Fue CO much ume < stack, active The rough about For e and s! condit volum of mo quent eratio this ¢ cal 1 econo the b Cor bustic volun rough Ba perin comb ward betw: can | woul and since prac tive ring cent of al the to b bust the | dime of 1 or { Thi: may pro incr com ing pre cou tior tuy } par ati spe ati ges leeconomy of Blast Furnace Operation 7, PS’ ov tt we & — SS Ss © much as the hearth area or the vol- ume of the bottom portion of the stack, but more as that of this most active region of gasification. These individual zones merge roughly into a ring before the tuyeres about the periphery of the hearth. For equal fuel economy in the large and small furnaces with the same base conditions, it would appear that the volume occupied by the ring or space of most active combustion and conse- quently that of the greatest heat gen- eration, should be proportional. If this condition is met, barring physi- cal uncertainties, should not fuel economy be proportional or better in the big unit? Considering the zone of active com- bustion more in detail, the individual volumes before each tuyere are roughly spherical, with a diameter of d=cD Based on observation and all ex- perimental data available, the active combustion area seems to extend in- ward from the tuyeres a distance between 0.10D and 0.20D in Ameri- can practice, as an average. Thus c would have a value of between 0.10 and 0.20. Assuming a value of 0.20, since the actual individual zone is practically globular, the area of ac- tive gasification in the combustion ring should occupy upward of 60 per cent of the hearth area for a height of about 0.20 D above the tuyeres. As the volume of a sphere varies as di’, to blow one furnace at the unit com- bustion zone rate of another making the same iron, with the same relative dimensions and shape, the quantity of wind necessary would appear as a = (cD)* or for average American practice d’ = (0.20D)* This agrees closely with Johnson® and may be more exact. Within limits proportionally more wind will tend to increase d, forcing the inside of the combustion ring inward, and consider- ing the furnace a unit volume, “com- pressing heat,” with variations, of course, for local and physical condi- tions, such as, for instance, different tuyere arrangement. Manifestly then, furnaces with com- Parable base conditions, with vari- ations in the volume of combustion Space, may be expected to show vari- ation in fuel consumption. The sug- gestion to furnaces, especially big ‘Johnson, J. E. Jr.—Work cited, p. 111. a mam & HY the fuel consumption of larger blast furnaces some- times exceeds that of smaller stacks led the author to speculate on what takes place in the com- bustion zone. He is of the opinion that economy of fuel may be owing more to getting the right amount of oxygen “properly” to the fuel than to any other one factor. vrvyv ones, with fuel consumption out of line, is obvious. Much has been written and more has been said considering the effect of coke ash on fuel consumption and the furnace process generally. While the factors are so inextricably linked that no particular phase can be ade- quately considered alone, it may not be amiss to consider the effect of ash in the light of what has been set out. Taking the proposed expression for the compressed heat effect F;, T.=Tx—xXk F If the fuel factors F and F, be taken as the actual amount of available car- bon, for any fixed quantity of coke the ash present will tend to decrease the unit volume quantity of available fuel by occupying space and so de- crease the amount that can be burned per unit of space per unit of time. This in turn will tend to decrease or shrink the size of the hottest region, because the dilution by inert matter will lower the zone temperature and decrease reaction. Thus would vari- ation of the actual fuel available in either of the factors F and F, affect the furnace process. The same effect | ee WN i Pi" Ui 2) o = S A r ; PeSSssSe7 Alt! | Pee | a | \ VN o { dal SDSS 1] would be true for two furnaces with otherwise comparable base conditions. The old question regarding the elusive and mysterious properties— inherent combustibility and reactivity of coke—which would give k a value remains. Many furnacemen subscribe to the idea that such a property ex- ists; others are uncertain. Most all agree that it is probable that any such properties are physical rather than chemical. A few are coming to the conclusion that any such qualities may be the result of sales propaganda of gentry with coke for sale. May it not be that the entire matter is more basically one of getting the right amount of wind to the fuel, properly? Malleable Institute To Continue College Aid DUCATIONAL facilities in behalf of the malleable iron industry pro- vided in the various technical schools and colleges during the last school year through the cooperation of the Malleable Iron Research Institute proved so beneficial that the institute, at a meeting in Cleveland, Nov. 15, decided to render the same service to these institutions during the current school year. During the last college year 71 in- stitutions availed themselves of the offer of the institute and these were supplied with over 6000 test bars and test specimens of malleable iron. In addition they were supplied with numerous castings for exhibit and in- struction purposes. Early this year the institute pre- pared a paper entitled “Malleable Iron a Typical American Product,” and offered to have this paper pre- sented to institutions interested by representatives of companies belong- ing to the institute and qualified to discuss the subject. Although the offer was not made until April 15, 20 schools took advantage of it and had the lecture presented. This was il- lustrated by 32 lantern slides. The institute has now decided to furnish a copy of this paper to the heads of the metallurgical and me- chanical engineering departments of technical schools to incorporate in their courses of instructions. In this way the paper will become text book material to be used from year to year and it is expected to have broader use than if its presentation were limited to a single lecture. The Iron Age, November 30, 1933—21 ENERAL ELECTRIC records indicate that up to about 30 years ago our average machine shop listed fully as many planers as milling machines in