The Iron Age 1936-07-23: Vol 138 Iss 4

23, 1936 “WHEN are you going start?” How save money replacement rusted cor- sheet metal parts, roofing and siding simple mat- ter. Use Toncan Iron the alloy refined open-hearth copper and molybdenum that provides the greatest any ferrous material its price class. Visit the Republic exhibit the Great Lakes Exposition, Cleveland, Ohio, June Oct. JUL Republic produces plain carbon steel, copper- bearing steel, copper-bearing iron, Toncan Copper Molybdenum Iron and Enduro Stainless Steel Sheets sheet for every degree cor- rosion-resistance. For more than years, Toncan Iron has been cutting replacement costs all branches industry through its long, trouble-free service life. You can start save money right now specify- ing Toncan Iron for all sheet metal work. you would like have the full story, write Dept. for copy “The Path Permanence.” REPUBLIC Republic Stee CORPORATION GENERAL OHIO BAA Pe The Wire that Made Electric Heat Possible Electric From heat heat, the boys the lab act steering committee for the mill. From carbon combustions metallurgical methods, the laboratory supplies the every steel mill laboratory, far know, Hoskins Electric Furnaces are continuous use this sort fact finding. Their easy control, uniform temperature, their long lasting elements meet the exact requirements the stee! mill lab smith shop. For useful furnace facts, send for Catalog Hoskins Manufacturing Co., Detroit Mich. 2—THE IRON AGE, July 23, 1936 THE IRON AGE, published every Thursday the CO., (INC.), Chestnut 56th Philadelphia, Pa. Entered class November the Post Office Philadelphia under Act March 1879. $6.00 year Canada $8.50, Foreign $12.00. Vol. 138, FRITZ FRANK, President VAN DEVENTER Editor Managing Editor Editor Emeritus Machinery Editor Art Editor Metallurgical Editor ASSOCIATE EDITORS RESIDENT DISTRICT EDITORS Washington Chicago Cleveland Detroit Pittsburgh EDITORIAL CORRESPONDENTS London, England Cincinnati Boston Hamburg, Germany Milwaukee San Francisco SANDERSON ASA ROUNTREE, JR. ALLISON CHESTNUT AND STREETS, PHILADELPHIA, PA. Toronto, Ontario Birmingham, Ala, Newark, Sales Offices Roy TURNER St. Louis Buffalo WEST 39TH STREET NEW YORK, Conten July 23, 1936 Alphonse and Gaston Annealing and Forging Standard Resistance Welders... Enameled Steel Sinks Produced Economically............ Higher Train Speeds and New Brake Shoe Problems...... Soda Fountain Boxes Assembled Projection Welding.. New Equipment ....... Automotive Industry .... Statistics Metal-Working Activity. Washington News NEWS CONTENTS ... Owned and Published Products Advertised ....... 107 CHILTON COMPANY Executive afd Publication Offices, Copyright 1936 Chilton Company (Inc.) Chestnut and 56th Sts., Philadelphia, Pa. BAUR, General Advertising Manager ture, JOSEPH HILDRETH, Indexed the Industrial Arts Index. and Chilton Bldg., Chestnut 56tb ‘ Sts., Philadelphia, Pa. GEORGE GRIFFITHS, Published every Thursday. Subscrip- Hottenstein. 802 Otis Bidg., Chicazo tion Price: United States and 7310 Woodward Detroit sessions, Mexico, Cuba, $6.00; Can- Ober, 239 39th St., New York ERNEST HASTINGS, ada, $8.50, including duty; Foreign Robinson, 428 Park Bldg., Pittsburgh $12.00 year. Single copy, cents. Sweetser, 239 West 39th St., New York WILLIAM BARBER, Treasurer Cable Address, ‘‘Ironage, Warren, Box 81, Hartford, Conn. JOHN BLAIR Secretary : j ae 3 x matte! No. : Ryerson cuts, bends, forms and the steel meet specifications Carrying large and complete stocks only part Ryerson Steel-Service. addition cutting and mak. ing immediate shipment all sizes and kinds products, experienced workers also bend, flange, weld, punch, and form all types assemblies exact specif. cations. Ryerson engineers are always pleased work with you not only secure the best design and the right steel but also assist methods Ryerson engineers will also help you solve any fabri. cating problems. Their wide experience with all types jobs may enable them point out better way handling your work. Tell what you require. will glad serve you, you not have the current Ryerson Stock List write and will forward copy. JOSEPH RYERSON SON, Chicago, Milwaukee, St. Louis, Cleveland, Detroit, Boston, Buffalo, Philadelphia, Jersey City. 18—THE IRON AGE, July 23, 1936 5 } | C wy, ESTABLISHED 1855 ... THE IRON AGE ... JULY 23, 1936 Alphonse and Gaston Reverse... OME you will remember the once popular newspaper cartoon presenting the two polite Frenchmen, Alphonse and Gaston. Each them would insist that the other take precedence all occasions when there was question who should come first. Thus the famous Present history, connection with the controversy between Mr. John Lewis and Mr. William Green presents the Alphonse and Gaston situation reverse. their mutually unselfish desire each assume the onerous task rescuing the forgotten and downtrodden laborer from the claws despotic employers who pay higher wages than ever before paid industry, the formula becomes: me, dear and me, dear That least the sense their communications the subject; the not, however, being quite polite. Mr. Lewis, heading the insists that and the cooperating Amalga- mated Association Steel and Tin Workers, shall solely permitted suffer and bleed for not only the rank and file steel employees but also for the skilled machinists, electricians and other craftsmen that industry whom Mr. Green considers fair game for the Mr. Green, equally eager sacrifice himself the altar common welfare, says that Mr. Lewis has call butt into this rescuing business, especially the latter not willing turn over the Amalgamated, the steel coal miners and the steel coke workers. The average American may wonder whence comes this inspiring desire the part each these two gentlemen become the exclusive champion labor and let the other sit back and take easy. That is, may wonder until mul- tiplies dues $12 per man per year 500,000 and discovers potential annual income $6,000,000 per year for somebody. Vol. 138, No. I | _ F | we : ¢ 4 | | 4 ance welding prima- rily method joining high speed and low costs, there are times when the process can adapted few simple changes operations quite differ- ent from welding. Using butt welder heat and bend stock forg- ings into variety special shapes one example. machine built like seam welder and used for continuous heating tubing and machine adapted heating and pulling wire apart are others. Still another these “by-prod- ucts” resistance welding that has great possibilities the use re- sistance heating for annealing metal parts, particularly when the section the whole piece, the case stamping which an- nealed prevent breakage when the part formed shape. The operation performed spot welder fitted with simple fixture like this. (See Fig. 1.) The current flows through the shanks which are attached the upper and lower arms the spot welder. The direction flow controlled the arrangement contacts and insulated blocks which prevent the current from passing directly through the stock and force flow through the area annealed. The cushioned faces the dies take care any slight ir- regularities the steel and assure uniform heat through the area be- tween the copper dies. Shaping metal upset heating butt welder also has time and money saving possibilities. One typical application this “by- product” the production automobile valves. The type valve produced this manner has collar part way down the stem that much greater diameter than the stem itself. one time was the practice machine the entire stem out length stock slightly greater diameter than the finished size the collar. Since these valve stems are produced large quantities, 20--THE IRON AGE, July 23, 1936 Annealing standa the waste time and metal in- volved reducing the stem size was important item. Resistance welding methods saved practically all this waste. Here how done: length stock slightly larger than the finished size the stem placed butt welder with the part the stock which the collar made located between the clamps. The heating current turned and the clamps are brought together until the upset bulge produces lump big enough provide for the collar. takes only few minutes machine Path Die Block away the excess metal and turn out finished stem complete with collar. Upsetting build the di- ameter stock can applied alloys well steel. The size the upset controlled the length push-up the butt welder. When one push-up does not produce sufficient length, the clamps can reset and the operation repeated several times necessary. Each time the clamps are reset and the stock pushed together bulge slightly smaller diameter Upper Arm Die -Copper Lower Arm | Copper--- | | duced and the same time, the bulge already the rod en- larged little more. the first bulge looks like diagram No. Fig. making three four more push- ups the same piece stock would produce effect such shown diagram No. When there considerable possible make large upsets single push-up rather than steps. The stock set the machine with one electrode clamp gripping the material firmly just one side the point where the Movable No.4 LEFT resistance welders bulge made. Another clamp, located the opposite side the bulge point, grips the stock tightly enough make good elec- trical contact but not too tightly prevent forcing the material through it. When the current turned on, the stock forced through the clamp slow speed, forming more symmetrical bulge than could produced the step method. Diagram No. Fig. il- lustrates this type bulge. Upset forging not limited making integral collars valve stems nor the location the No.5 BRIGGS Research Engineer, Thomson Gibb Electric Welding Co., Lynn, Mass. ° ° ° bulge necessarily limited point between the ends the stock: The heads poppet valves can built valve stems using solid block instead one the electrode clamps. the step the con- tinuous feed method can used this work shown diagrams and Fig. This type work can done machine which automatically feeds the stock and cuts off and ejects enough material for each valve. always possible produce more than one upset the same length stock actually forge the metal into some special shape means dies that come from the sides while the stock still hot the upsetting machine. Fic. metal parts performed spot welder fitted with simple fixture. ABOVE 2—Size upset controlled the length push-up the butt welder. When one push-up does not produce bulge sufficient diameter length, the clamps can reset and the operation repeated number times. THE IRON AGE, July 23, porcelain enamel pressed steel sink. This done enlarged booth and the work revolved pedestal while being sprayed. THE increased use vitreous enameled steel the manufac- ture equipment for the home and the enameling products not formerly made stampings has brought out new manufacturing problems. Makers who have led the way develop- ing new applications steel for articles that provide home con- venience and comforts and are attractive appearance find necessary develop efficient mass production methods that will per- mit them make product that can put the market price that sufficiently low make successful from sales volume standpoint. Even the product far supe- rior article made for the same purpose from material other than steel, the competition tween the two products likely keen and the opportunities the maker broaden the mar- 22—THE IRON AGE, July 23, 1936 ket for his improved product are increased his ability reduce production costs. Pressed steel porcelain enameled sinks are one the more recent products the stamping and enameling industries. The Youngs- town Pressed Steel Co., Warren, Ohio, was pioneer the de- velopment these sinks. When this company started making the sinks 1932 they were enameled the large and efficient plant that had been provided for the porcelain enameling washing machine tubs, which this com- pany one the largest manu- facturers. New problems handling, spraying and firing appeared manufacturing vitreous enameled sinks because their size. The sinks the standard drainboard type are made 14-gage steel three models, in. in. long and in. wide, the largest weigh- ing lb. The complete which includes the back and apron, one-piece stamping and over drawing and forming opera- tions are required converting flat steel blank into its finished form sink. The size the sink indicates that has very large surface enameled. handle the ° ° ° PRENTISS Cleveland Editor, The Iron Age ° enameling more efficiently and provide fine coating pos- sible the Youngstown company re- cently equipped new vitreous enameling department, which used exclusively for enameling the sinks. also put new grinding mills adjoining this department for grinding the enamels and special pickling unit. The present press equipment also will aug- mented the addition large press for some the operations. Duplicate Units The enameling layout consists two duplicate units located side side conveniently and com- pactly arranged. Each unit sists three spray booths ar- ranged row served chain- type, variable-speed conveyor which carries the pieces suspended hooks through drying oven. the unloading end the oven the conveyor makes 90-deg. turn short distance provide un- loading space and the sinks are taken from the conveyor the burning furnaces few feet away and line with the spray booths and drying ovens. The spray booths are stand- ard design, but slightly remodeled make them large permit the sinks — j 4, a | | | ENERAL view the department for spraying vitreous enamel steel kitchen showing spray booth and dryer equipment and conveyor han- dling work process. INKS when car- ried through the firing burning tools having numerous points and blades which form tour sponds that the under surface the sink. This method handling through the burning furnace seded carrying the pieces suspended hook through furnace, because when the latter meth- was followed many the sinks be- the furnace. THE IRON AGE, July 23, 1936—23 y a pedestals which they are set while being sprayed. They are enameled both sides and be- cause inconvenient, owing their size, handle them and out dipping tanks, the ground coat well the cover coat sprayed on. However, flat rim sinks, which are much smaller and lighter, being 18-gage steel, and much simpler construction, are dipped for the ground coat. Two the spray booths each unit are placed face face, bringing the men operating the spray guns these booths close together that convenient for one assist the other handling sink and from the booth. Enameling materials are placed tanks platform above each set spray booths and the enamel fed gravity from these tanks the nozzles the spray guns. Heat Circulating Duct Dryer The dryers are ft. long, ft. wide and ft. high. They are direct gas fired through heater from which the air circulated through the dryer. The inacces- sibility some the surfaces presented problem assure the proper rapid drying, but this was solved the provision spe- cial heat circulating duct. The sinks are dried temperature 300 deg. and are kept the dryer min. for the ground coat and min. for the cover coat. Each unit has capacity for drying 60-in. sinks per hr. The dryers were built the Smith-Mayer Corp., Cleveland. Two white color coats are usu- ally applied and all sinks are given acid-resisting coat after cover coating. the application the cover coating requires more time than the single ground coat, the dryer and three spray booths used for the ground coat are also 24—THE IRON AGE, July 23, 1936 utilized part the time for the cover coating. This also true the furnace which the ground coat burned. New Burning Furnaces The sinks formerly were burned continuous electric furnace through which they passed sus- pended conveyor hook. How- ever, this method burning did not prove efficient for work the size sink with great deal flat surface, caused many the sinks become distorted the furnace, necessitating their rejection. The new burning equipment con- sists two ft. box-type, V-bottom muffle gas fired fur- naces equipped with automatic gas control and temperature recording instruments. removal from the conveyor after leaving the dryer, the sinks are placed burning tools one two charging forks. These burning tools, heat resisting steel, consist frame bars and angles that support numer- ous points and blades all welded together and forming contour that eorresponds accurately that the sink. Resting these tools the sink retains its shape during burning and rejections because warping have been entirely elim- inated. The capacity each burn- ing furnace four large sinks. The furnaces were built the Ferro Enamel Corp., Cleveland. The ground coat burned 1550 deg. F., the sink remaining the furnace min. longer period than for smaller work like washing machine tubs. After the ground coat the sink taken off the burning tools and inspected and pieces having defects enam- eling are re-routed the spray booths. Sinks which the ground coat passes inspection the cover coat spray booths and after spraying are dried the same temperature the ground coat. Then they return the burning furnace where they are burned follows inspection bench under the illumination two 500- watt daylight lamps. Protected Canopies very important vitreous enameling that the work kept free from dirt and dust during processing and handling. avoid danger that the graphite and heavy oil lubricant used the conveyor might drop the work from the conveyor chain, the sinks are protected while moving the conveyor hooks canopy. This consists sheet metal pans with turned flanges attached directly under the conveyor chain. There pan above each hook, the pans being in. long that their ends overlap the hooks which are 24-in. centers. Air delivered the dryers cleaned filters and the heater equipment totally enclosed filtration. hood located di- rectly front each furnace door through which air hausted into stack. This pre- vents dust from settling the sinks when loaded the forks preparatory being charged in- the furnace. The pickling unit provided for pickling the sinks before spraying located adjoining rodm through which the sinks are routed from the stamping plant. This all steel except acid tank. The latter rubber-lined and has sandstone slabs along the inner surface protect the lining from contact with the work. 3 f SURFACE hardening steel may accom- often loss decide which method choose. true that metallurgical literature abounds with information covering al! phases each hardening process. However, the average user treated steels often too busy with other problems give the matter the study necessary cor- rectly evaluate each procedure. review all surface hardening methods one short article. should pointed out, however, that surface hardness may ac- complished cold work fusing harder layer the sur- face welding. This article, however, will confine itself the processes which carbon ni- trogen added the surface produce hard surface layer. Hard surfaces desired for the purpose resist- ing wear, although later sections this review show that resistance corrosion sometimes pri- mary purpose. When steel hardened the use carbon, there depen- dence the carbides iron and the carbides other alloying ele- ments which the steel may con- tain for the hardening constitu- ent. When steel hardened means nitrogen, the action de- pends nitrides certain the metallic elements. Carbides are soluble steel ordinary temperatures only very limited extent, but when heated above the lower critical point known the Ac, point, hardening EAKIN Metallurgical Engineer, Westinghouse Electric Mfg. Ce. ° ° ° change takes place resulting the solubility being creased. This point about 1350 deg. for carbon steels. order harden carbon steels, first necessary that the carbides dis- solved before quenching. Low-car- bon steels not harden much quenching because the lack HIS elementary but interesting and valuable discussion two methods surface hard- ening known carburizing and nitriding. The nature carbides and nitrides con- sidered, and the processes and equipment which they are obtained the surface material steel the most desirable form are described and illustrated. Types steel most commonly used are list- ed, and the characteristic properties resulting from each method are discussed, all with the intention aid- ing reader determine whith best adapted his particular problems. iron carbides, but the carbon content increased the hardness resulting from quenching from above the temperature range increases very rapidly. the quenching sufficiently dras- tic, steel 0.90 per cent carbon above will become extremely hard. High-carbon certain alloy steels may quenched produce very high hardness, but these steels harden deeply and this condition are too brittle and full internal stresses withstand even ordinary service conditions. fact, the steels are not tem- pered they may crack storage, did the high-carbon 4-in. di- ameter plunger shown Fig. These internal stresses may, course, relieved suitable tem- pering treatment but the sacri- fice part the desired surface hardiness. material has yet been found that combines high shock resistance with high hard- ness. compromise must, there- fore, made. The most practical compromise yet devised the case steel that surface harden- ing. steel properly selected and treated, this process produces hard though brittle case sup- ported relatively tough shock- resisting core. Action Carburizing The method which carbon added the surface material steel naturally called carburiz- ing. For this purpose steel selected not high enough carbon other alloying elements quench-harden the core when the part, after having been carburized, quenched for hardening the case. must, course, remembered that surface hardening the car- burizing methods consists two THE IRON AGE, July 23, 1936—25 | 3 | | | q | | i { steps. First, dissolving quired amount carbon the surface material, and second, quenching obtain the required hardness. Dissolving the required amount carbon the surface material, the carburizing part the process, consists essentially heating the steel atmosphere carbon monoxide and holding 1700 deg. until desired depth high-carbon case obtained. The steel may (1) packed carbonaceous material vessel, sealed, placed furnace, and heated “pack carburizing”; (2) heated furnace having carefully controlled carbon mon- oxide atmosphere “gas car- molten salts which slowly de- compose give off carbon-bearing gases, “liquid carburizing.” each instance, the active carbon transfer agent carbon The carbon content highest the surface, being usually about 1.20 per cent, and diminishes concentration until the core reached. After carburizing, the steel must quenched from about 1400 deg. harden the case. the best combination hard- ness and toughness ob- tained the steel must given two quenches. The first quench from about 1600 deg. order re- fine the grain the core and dissolve the excess carbides the hypereutectoid zone (portion the case containing more than 0.90 per cent carbon) the case. The second quench from about 1400 deg. F., which refines the grain the case and hardens without disturbing the grain the already refined core. The steels commonly used for carburizing are listed Table modern continuous gas carburiz- steel plung- hardened quenching. The internal stresses were not removed temperina; for this reason the steel cracked, shown here. ing furnace shown Fig. The charge can seen entering the furnace. Action Nitriding Nitriding, which the name given the process which ni- trogen introduced into the sur- face material steel, consists essentially heating the steel temperature from 977 deg. 1112 deg. closed con- tainer through which ammonia gas passed. Part the ammonia broken into hydrogen and nitrogen gas. The nitrogen reacts with the surface material the steel form nitrides which slow- diffuse into the steel form the case. process which heat ap- plied steel means molten salt and the prepared nitrogen gas TABLE Steels Commonly Used for Carburizing 1015 0.10 0.20 0.60 1020 0.15 0.25 0.30 0.60 2320 0.15 0.25 0.30 0.60 8.25 3.75 2512 0.17 Max. 0.30 0.60 4.75 5.25 3120 0.15 0.25 0.30 0.60 1.00 1.50 0.45 0.75 4615 0.10 0.20 0.30 0.50 1.50 2.00 0.20 0.30 4620 0.15 0.25 0.30 0.50 1.50 2.00 0.20 0.30 6120 0.15 0.25 0.30 0.60 0.80 1.10 0.15 Min. 26—THE IRON AGE, July 23, 1936 applied bubbling through the liquid used some extent. The depth case depends main- upon time, temperature, and ammonia dissociation. Fig. shown bell-type nitriding fur- nace. The charge shown assem- bled the furnace base. The floor grating next removed and the inner shell, which shown suspended from the crane, low- ered over the charge. The bottom flange the inner shell fits into oil-filled groove the base, forming seal for confining the gases the inner shell. The outer shell, which contains most the electric heating elements, next lowered over the inner shell. The furnace then brought temperature and the ammonia gas introduced into the inner shell. sectional view the furnace shown Fig. The process confined steels containing elements favorable the formation nitrides. Chief among these elements are alumi- num, chromium, molybdenum, and vanadium. Nickel sometimes added core stiffener. Many metallurgists consider necessary constituent nitrid- ing steels for the purpose cir- cumventing any tendency for tem- per brittleness which may accom- pany some the other alloy com- binations. There are number steel com- positions which respond nitriding process, such as_ the chrome-vanadium steels (SAE 6100 series), the vanadium steels higher chromium, with with- out nickel, and the high-speed and chromium tool steels; but the steels which have found widest use are listed Table II. the lists carburizing and nitriding steels (Tables and II), the high sulphur, free machining types steel have been omitted. true that great deal bessemer and open hearth screw stock being carburized, and free cutting nitriding steel has been used some extent. Gen- erally speaking, these steels are more subject segregation and elongated inclusions than_ the straight carbon steels. This seri- ously affects their transverse strength, and for this reason more trouble may expected from when quenched. Also, these steels, when nitrided, suffer from corrosion pits. choosing between regular and free machin- > = > ing grades steel, the gain duc the free machining property must balanced against the cost due rejected parts and field trouble. There are many applica- tions, especially where the part used compression, where these steels may used very satisfac- torily for surface hardened Cost Advantages From the standpoint commer- cial availability and cost, carbu- rizing steels generally have con- siderable advantage ing steels. The nitriding steels, while possessing properties, have special attrac- tion this respect that cannot met the more widely used alloy steels. Being therefore limited nitriding applications, the tonnage consumed small and the price much higher than the more com- monly used alloy steels equal strength. Because the small turnover, prompt deliveries are not always obtainable. TABLE Steels Favored for Nitriding Element Alamo Nitralloy Nitralloy 0.30 to 0.40 0.20 to 0.30 0.30 to 0.60 0.30 to 0.60 0.30 Max. 0.30 Max. 0.75 1.50 0.75 1.50 1.00 1.50 1.00 1.50 0.15 0.25 0.15 0.25 evaluating the carburizing and nitriding methods surface hardening, there are several fac- tors considered. First, con- sider machineability. this con- nection, should remembered that carburizing steels are almost always machined the annealed soft condition, while nitriding steels are used harder struc- tural condition, commonly known reference the former, the steel carburized used the soft condition chiefly facilitate ma- chining and obtain greater free- dom from internal stress. Since steel undergoes complete struc- tural change during carburizing and heat treatment, there advantage machining other than the soft condition. The situation with regard nitriding steels entirely differ- ent. The nitriding temperature, which approximately 977 deg. 1112 deg. F., only high structure down approximately the sorbitic state. Since the time bed Fic. charge entering modern gas carburizing furnace the continuous type. Furnace made Surface Combustion Co. THE IRON AGE, July 23, 1936—27 4 ba mae 3—A bell-type electric nitriding furnace. The charge placed the base ready for the floor grating removed and the inner shell (shown suspended from the crane) placed over it. The outer shell containing most the heating elements then temperature during nitriding ture, there would object machining harder condition because the extra core hardness would lost due the tempering effect the nitriding tempera- ture. the other hand, since the nitriding temperature not temper the steel softer than the sorbitic state, advantageous use the steel this condition the interest greater core strength even though the machin- ing little harder. Aside greater core strength, there additional advantage more uniform mi- crostructure. One the cardinal principles the successful quench hardening carbon steel uni- form microstructure. The same holds true for nitriding. The de- velopment sorbitic structure involves heating and quenching from above the upper critical point which tends produce more homogeneous material. Thus, addition greater core strength, the material more dependable. 28—THE IRON AGE, July 23, 1936 placed over the inner shell. However, sacrifice made machineability. offset the lower cost per pound, the greater availability and better machineability the carbu- rizing steels, the nitriding process has some favorable with which carburizing cannot compete. Among these are (a) higher hardness, (b) less distor- tion, (c) high corrosion resistance. The order hardness commonly associated with nitrided parts from 800 1100 Vickers (about 627 745 Brinell), while that for carburized surfaces from Scleroscope (about 495 653 Brinell), corresponding about 567 835 the Vickers machine. wear resistance the chief fac- tor, nitrided surface will often succeed where carburizing has failed. Distortion hardened parts often very troublesome problem, especially when must maintained. The causes for distortion during surface hard- ening may divided into (a) those independent the surface TABLE Effect Elevated Temperatures the Hardness Nitrided and Carburized Surfaces Tempering Temperature Deg. (Time hr.) Nitrided Carburized (Steels Table II) Steel) 1100 800 1100 680 1100 580 1100 440 1060 390 | | t | | | | | 4 hardening method used, and (b) those incident the method. Among the former may men- tioned the size and shape the part, section, re- entrant angles, ratio core sec- tion that case, residual stresses left from machining forming, etc. These factors must given careful consideration re- nitriding used. However, may safely said, for reasons that appear later, that even these were the only distortion factors, the parts nitrided will suffer less distortion than hardened the carburizing method. Among the causes for distortion incident the method used may mentioned thermal Thermal stresses are caused un- equal heating and cooling. Nitrid- ing, has been seen, not only involves relatively low tempera- tures compared carburizing, but, still more important, the ni- trided parts are cooled the fur- nace, whereas must quenched least once obtain hardness. Two quenches are required the best combina- tion toughness and hardness obtained. Another factor which contrib- utes distortion surface hard- ened parts incident the method the stresses resulting from vol- ume changes accompanying the structural changes which the steel undergoes when passing through the critical range. Since the tem- peratures used nitriding are be- low the critical range for the steel, nitrided parts are not subject distortion from this cause. the other hand, with the carburizing method, the steel passes through the critical range two more times. the parts are heated cooled slowly “pack carburiz- ing” the distortion during the car- burizing part the process may disregarded, but, during quench- ing, where different sections the part may pass through the critical range slightly different times, quite appreciable distortion may take place from this cause. Here again the amount distortion will depend greatly the shape the piece. Nitrided surfaces have the abil- ity retain their hardness after having been heated elevated temperatures better burized surfaces. This relation shown Table III. Sheet Chamber Seal Fic. 4—A cross-sectional view the bell-type nitriding furnace shown Fig. will noted that the tem- pering temperatures have had effect the hardness the ni- trided surfaces. However, above 200 deg. F., the carburized surface lost hardness quite rapidly. This property nitrided steel con- siderable value for parts subject heating, bearing that must run dry. the matter corrosion re- sistance, nitrided surfaces stand class themselves. Carburiz- ing can make claims for corro- sion resistance, while properly ni- trided surfaces rank with stainless steels this respect. This prop- erty, coupled with extreme hard- ness, makes nitriding particularly attractive for mechanical parts used corrosive atmospheres, where corrosion would interfere with proper performance the mechanism. Quite frequently nitriding used primarily for its corrosion resistance. One the essentials that the proper degree satu- ration nitrides present the outer case. very thin case, say 0.005 will usually not resist corrosion well heavy case about 0.020 in. depth. Large inclusions surface defects which prevent proper nitriding are likely result corrosion. Grinding after nitriding should avoided possible because may through the case un- cover some ferrite particles which will readily rust. Considering the extremely small distortion result- ing from nitriding, parts can usually finish-machined and ground before nitriding, which makes possible take full ad- vantage the corrosion resistance the case. Summarizing, may say that carburizing steels cost less, ma- chine more readily, are less liable spall, and are more commer- cially available steels. Carburized parts may tempered varying combinations hardness and toughness, while this not practical with ni- trided parts. The practical depth for car- burized case in. more, while nitriding seldom carried beyond 1/32 in. Nitriding pro- duces higher degree hardness, results much less distortion, and provides enormously higher cor- rosion and heat resistance than can obtained the carburizing process. THE IRON AGE, July 23, 1936—29 risers from castings foundry. The work was previously done with acetylene. was not until the Penn Fuel Co. piped gas into Pittsburgh from the Murraysville gas field 1878 that the real foundation the natural gas in- dustry was laid, although natural gas was used for lighting and ing Fredonia early 1825. After nearly years service, natural gas still holds strong place public and industrial use and important source sup- ply the heavier hydrocarbon gases, propane and butane. The saturated hydrocarbons which are gaseous normal tem- peratures and pressures are me- *Paper presented before the National Association Power Engineers, Phila- delphia, April 10, 1936. 30—THE IRON AGE, July 23, 1936 thane, ethane, propane and butane. The first two are well known fuels and the last are the subject this paper. Their principal prop- erties are shown Table Have Advantages Other Gaseous Fuels Liquefied petroleum gases have all the advantages the older gaseous fuels: efficiency, cleanli- ness, simplicity utilization, and controllability, and may han- dled and stored similarly oil. One the most important oper- ations the development the liquefied petroleum gas industry transportation between the source supply and the consumer. Until recently, the producer and consum- have been separated consid- erable distance, since the chief producing plants are located prin- cipally the active oil fields while the potential markets extend those sections far removed from these points. This ° ° ° MARTIN CONWAY Fuel Engineer, Lukens Steel Co., Coatesville, Pa. ° ° ° large quantities liquid must transported over long distances safe and economical means. Prior 1927, nearly all these liquid gases were transported metal cylinders, that only those consumers who were within reason- able distance the source sup- ply could economically fuels. Since then the development special tank cars, motor trucks, and boat and pipe line facilities, plus the more widespread produc- tion refineries, have helped account for the increase annual consumption total 63,000,000 gal. 1935. The greatest increase the utilization these gases taking place the industrial and domes- tic fields shown Table II. Quantity Almost Unlimited Liquefied gas produced from natural sources almost unlimited quantity. Its distribution from these sources has been, re- = | | cently, somewhat limited their geographical location with refer- ence the consuming areas. Now that the minor difficulties manufacture have been over- come refineries, this source supply for liquefied gas products becoming increasingly impor- tant, and propane the gas that increasing proportion the total marketed production lique- fied petroleum gas, not possible utilize this material gasoline know today. the case butane, commer- cial operations have been started during the past year the con- version butane into gasoline and safe assume that will be- come more widely used in- gredient motor fuel, that its amount and availability for other uses large quantities proble- matical. The production propane from refinery gases will tend eliminate the problem distribution which has been great factor the in- dustry. The distribution liquefied pe- troleum gases for industrial uses has the past been limited largely shipment tank cars ap- proximately 10,000-gal. capacity. The development steels has, however, given impetus the use the tank truck and now becoming common practice haul relatively small quantities over considerable distance this manner. the Pacific Coast, truck and trailer units are hauling both propane and butane approxi- mately 300 miles from the source supply. Specifications Large Producer The following specifications are those used one the largest producers and marketers lique- fied petroleum gases for number its products: Industrial Propane: The composition shall least per cent propane and/or propylene liquid volume. The vapor pressure 105 deg. determined the liquefied petroleum gas vapor pressure method shall not excess 225 lb. per sq. in. gage pressure. Not less than per cent volume shall evaporate below temperature —25 deg. determined the open cylinder weathering test. The product shall free hydro- gen sulphide. The flash vaporized product shall not contain total sulphur excess grains per 100 cu. ft. vapor, determined the test for total sul- phur liquefied petroleum gases. The product shall free en- trained water. G-3A propane same commercial propane except for water content and need not included. Commercial Propane: The composition shall least per cent propane and/or propylene liquid volume. The vapor pressure 105 deg. determined the liquefied petrol- eum gas vapor pressure method shall not excess 225 Ib. per sq. in. gage pressure. The residue determined means the mercury freezing test shall not more than per cent volume. The product shall free from hy- drogen sulphide. The flash vaporized product shall not contain total sulphur excess grains per 100 cu. ft. vapor, de- termined the test for total sulphur liquefied petroleum gases. The degree dehydration shall such that the product will pass the standard cobalt bromide test. Commercial Butane: The product shall composed predominantly butanes and/or butylenes. The vapor pressure 105 deg. determined the liquefied petrol- eum gas vapor pressure method shall not excess per sq. in. gage pressure. Not less than per cent volume shall evaporate below mined the open cylinder weathering test. The product shall free hydro- gen sulphide. The flash vaporized product shall not contain total sulphur excess grains per 100 cu. ft. vapor de- termined the test for total sulphur liquefied petroleum gases. The product shall free en- trained water. Wide Industrial Uses can but give indication the various domestic and industrial uses which these liquefied pe- troleum gases can adapted. These gases may used form community service domestic consumers transportation bulk from the place where they are produced and then vaporized central plant for distribution. this service the gas can dis- tributed the undiluted form diluted with air before distribution. For small communities where the higher capital cost gas manu- GENERAL view heat-treating department using propane gas. THE IRON AGE, July 23, ~ is per facturing plant cannot justified, this process has great economic possibilities. Both butane and pro- pane can also used place oil gas enrich water gas where this normally made meet fluctuating loads, and this sense their constant heat value and easy operation make them very conve- quite few estates near Phil- adelphia there have been installed 1350-gal. propane capacity tanks, taking 1000-gal. deliveries, for pro- viding gas operate gas boilers, unit space heaters, gas ranges, clothes driers, mangles and other gas-fired appliances which are found the large estates. One hotel neighboring town uses this gas for its kitchen stoves, hot plates, coffee urns—in fact, every place where gas used, including the electrically operated gas pilot light for the oil-burning heating plant. Cutting and Brazing Metals ture liquefied petroleum nient use. TABLE CONSTANTS LIQUEFIED PETROLEUM GASES (All Values Not Otherwise Designated Are Deg. and In. Mercury) Item No. Characteristics Ethane Propane N-Butane Isobutane Normal state deg. and in. Mercury............ Gas Gas Gas Gas Specific gravity liquid deg. F./60 deg. F............ 0.3738 0.5089 0.5824 0.5665 247 147.1 111.5 118.3 Boiling point liquid— Melting point solid— 10. Critical data— (b) per sq. in...... 648.1 552.4 538.23 Van der Waals constants— 1074 1727 2883 2562 12. Specific heat gas— Heat formation constant pressure— 14. Latent heat vaporization normal boiling point— 232.2 192.6 173.52 169.92 15. Viscosity C.G.S. Units deg. C.)........ 929 806 744 16. Cu. ft. vapor per Ib. liquid— deg. and im. 12.594 8.588 6.5154 6.5154 17. Cu. ft. vapor per gal. liquid— deg. and in. 39.211 36.398 31.602 18. Lb. per gal. deg. 3.1185 4.8544 4.718 19. B.t.u. per cu. ft. vapor— deg. and in. 1,764 2,519 3,274 22. Limits inflammability— 23. Maximum rate flame TABLE III: COMBUSTION DATA Cu. Ft. Required per Products Pounds Required Products —Cu. Ft. Combustion for Combustion Combustion Gas Vapor Cu. Ft. Formed Gas Vapor Ib. Gas Vapor Flame for Combustion Burning Cu. Ft. Ib. Pounds from Burning Carbon Carbon erature Air Oxygen Dioxide Water Nitrogen Air Oxygen Dioxide Water Nitrogen Deg. 16.738 3.5 2.0 3.0 13.238 8.728 2.929 1.799 12.404 3670 5.0 4.0 18.912 15.712 3.631 2.996 1.635 12.081 3710 31.086 6.5 4.0 5.0 24.586 15.495 1.551 11.914 3735 31.086 6.5 4.0 5.0 24.586 15.495 1.551 11.914 32—THE IRON July 23, 1936 a ° ° ° lead melting furnace fired with propane pressure. ° ° lower than that acetylene, this does not preclude its use for cut- ting steel and brazing metals and alloys low melting point such brass and bronze, the weld- ing aluminum and lead burning. extensively used foundries for cutting risers from castings and used some steel plants for and the cutting slabs fact, the lower flame tempera- ture some ways positive ad- vantage, serves prevent the burning the work unskilled hands and produces sharper edges. Combustion data are shown Table III. Those industrial applications which show noticeable increase are direct fired air heating for plant space heating, metal cutting, atmospheric control, particularly (CONCLUDED PAGE 59) ROPANE heat-treating de- bearing plant. ° ° TABLE MARKETED PRODUCTION LIQUEFIED PETROLEUM GAS Year 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935* *Estimated. Bottled Gas 2,600,000 5,900,000 11,800,000 15,294,648 16,244,103 16,625,588 17,681,000 20,700,000 Industrial and Miscel- Gas Manu- Total Gal. laneous facturing per Year 222,641 376,488 465,085 1,091,005 400,000 1,500,000 4,522,899 1,500,000 2,500,000 9,930,964 2,200,000 4,000,000 18,017,347 7,171,686 6,303,242 28,769,576 8,167,194 9,703,470 34,114,767 13,987,095 8,318,325 38,931,008 24,202,000 6,290,000 48,173,000 36,000,000 6,300,000 63,000,000 THE IRON AGE, July 23, 1936—33 - q speeds has not been without reverberations the direction component parts and materials. interesting example con- nection with brake shoes. The advent higher speed train operation has received most public notice, perhaps, connection with the streamlined, articulated type unit. Although lighter weight, many these have fewer wheels, with the result that the load per wheel some the trucks actually greater than that the conventional trains, this be- ing especially true the unit. Since braking train the TEPPING railroad train Higher train speeds give rise energy heat that must dis- sipated the brake shoe each wheel varies directly the weight the wheel and the square the velocity, apparent that these trains open new range braking problems, particularly high speeds. fact, the desire the railroads able stop these trains, traveling 100 miles hour, the same, less, distance the con- ventional standard train traveling braking problems have also been created heavy freights that, latterly, operate schedules ap- proximating those express trains. both cases the problem stop the train with safety and comfort and within the distances prescribed. Develops Equipment Study New Problems What changes, any, must made equipment brake these trains safely and efficiently are be- ing studied the American Brake Shoe Foundry Co. its Mahwah, J., plant, using the new large brake shoe testing machine here illustrated. This machine permits laboratory duplication the ing passenger and freight cars under extreme modern conditions, brake shoe testing machine designed and developed the engineering staff the American Brake Shoe Foundry Co., cooperation with equipment manufacturers and railroad officials. will used study braking problems arising from higher speed train operation. 34—THE IRON AGE, July 23, 1936 — | new brake shoe problems during stop, slowdown, control grade,—or the entire sequence braking during the operation train between two points. This machine was put through its initial demonstration July Trainer, vice-president, the new laboratory named for Sar- gent, chief engineer, American Brake Shoe Foundry Co., who for years has been active brake shoe engineering. Operation the machine was demonstrated series six runs, using two standard 18-in. “Diamond brake shoes heat-treated rolled steel wheel driven 60, and 120 miles hour. Three the tests were with wheel load and total brake shoe pressure 27,500 lb. for both shoes, and three others were run total shoe pres- sures 200 per cent the wheel load, 55,000 for both shoes. loads conventional trains are said average present about 16,000 The new machine growth similar testing equip- ment installed the same plant 1910 but much more flexible control and has almost double the speed and load capacity. The older machine was used both for development work and for routine sample testing the brake shoes produced the more sub- sidiary foundries the company. The latter the nature “end the quality the materials and foundry practice the making this important rail- road car equipment. Shoes Tested 150 Mile-Per-Hour Speed Brake shoes car wheels rang- ing from in. in. diam- eter are within the capacity the new machine. With 33-in. wheel, speed 150 miles hour can obtained and wheel loads rang- ing from about 4000 Ib. minimum about 40,000 lb. maximum. Brake shoes may applied the car wheel either single clasp brake arrangement, with maxi- mum brake shoe load 55,000 Ib. each shoe. recording mechan- ism graphs accurate record the brake shoe pressure, torque, and air pressure for each shoe. Wheel load obtained terms energy from rings flywheels carried roller bearing shaft. There are seven these rings various weights which may ar- ranged give combinations wheel load. car wheel mounted one end the shaft with the driving motor the opposite end. means overrunning clutch, the armature the motor auto- matically disconnected from the shaft when making stop, thereby removing any motor influence the wheel load energy. The brake shoe applied the tread the wheel through mechanism op- (CONTINUED PAGE 58) the new brake shoe testing machine centered this cabinet, which also equipped with recording instruments that furnish all details the action full size brake shoes full-size car wheels throughout the entire braking cycle. THE IRON AGE, July 23, 1936—35 4 - ee | < } } IMPROVE New Model Double Threading Machine Features Detail Improvements machine the Acme Machin- ery Co., Cleveland, presents sturdily built, high production ma- chine modern design. new cleanlining the bed adds ap- pearance, and carbon steel, heat- treated ways add machine life. The carriage has extra long sup- porting surfaces, gibbed provide take-up for wear. Carriage move- ment may either handwheel lever. Telescoping guards are attached the carriage for pro- the ways from dirt and Levers are easy operator reach. Speed changes are accomplished through tained selective type gear box means levers the front the machine; index plate indicates the proper position each lever for any desired speed. Acme tangent die head con- sists two parts, ring and barrel. hardened and ground steel forg- ing die block operates long hardened tool steel bushings the die ring, and between hardened and ground plates the die bar- 36—THE IRON AGE, July 23, 1936 rel. The construction contemplates long life and accurate die aline- ment. Adjustability the die ing screw the top the die. Bearing surfaces three sides the die pr