The Iron Age 1934-09-27: Vol 134 Iss 13

00 r of 30ci- W il- Nov. kers ker, ech- igh- ook, tute resi- ‘ato- lent, 1 R. Col- dis- r as otal- lene and the uca- ond .. THE IRON AGE .. September 27,1934 .. Jj. H. VAN DEVENTER G. L. LACHER Ww. W. MACON T. H. GERKEN R. E. MILLER Editor Managing Editor Consulting Editor News Editor Machinery Editor F. J. WINTBRS T. W. Lippert G. EWRNSTROM, Ju BURNHAM FINNBEY GERARD FRAzAR Pittsburgh Detroit Boston F. L. PRENTISS R. A. Fiske A. I. FINDLEY L. W. Morrett R. G. McIntos# Cleveland Chicago Editor Emeritus Washington Cincinnati “ Contents A Message to the Metal Congress 11 Non Ans st 01500 Fuel Economies in Refining Iron 13 Shot Weld—A Closely Controlled Process 18 Advanced Practice in Brass Rolling 22 Exhibitors in Metal Exposition 28 Heat Treatment of Rainbow’s Stay Braces 30 In Business Risk Lies Social Safety 32 New Bquipment 36 Meeting of Iron and Steel Electrical Engineers 46 News 51 Washington News 53 Personals and Obituaries 55 Automotive Industry 56 Markets 59 Construction and Equipment Buying 80 Products Advertised 172 Index to Advertisers 194 rv Ww THE IRON AGE PUBLISHING COMPANY v J. FRANK, President G. H. GRIFFITHS, Secretary C. 8. BAUR, Generali Advertising Manage: PUBLICATION OFFICE: N. W. Corner Chestnut and 56th Sts., Philadelphia, Pa. EXECUTIVE OFFICES: 239 West 39th St., New York, N. Y., U.S. A. ADVERTISING STAFF Member, Audit Bureau of Cireulations Emerson Findley, 311 Union Bidg., Cleveland Member, Associated Business Papers B. L. Herman, 675 Delaware Ave., Buffalo, N. ¥ H. K. Hottenstein, 802 Otis Bidg., Chicago Published every Thureday. Subscription Price Peirce Lewis, 7310 Woodward Ave, Detroit United States and Possessions, Mexico, Cuba Charles Lundberg, Chilton Bldg., Chestnut & $6.00; Canada, $8.50, including duty; Foreign 56th Sts., Philadelphia, Pa. $12.00 a year. Single Copy 25 Cents ©. H. Ober, 239 W. 39th St., New York Cable Address, ‘‘Ironage, N. Y."’ W. B. Robinson, 428 Park Bldg, Pittsburgh W. C. Sweetser, 239 West 39th St., New York D. C. Warren, P. O. Box 81, Hartford, Conn. _ EIGHTIETH YEAR OF SERVICE TO THE METAL WORKING INDUSTRY | nh = i | 1 | i inate neces il cite ih al a eileen ie aa THE IRON AGE. SEPTEMBER 27, 1934 Page 10 BGETHANIIED WIRE ERE are some of the products in which the properties of Bethanized Wire have been found of great value. Bethanized Wire is far ahead of zinc-coated wire made by older proc- The thickness of coating that can be applied — its ability to stand bending and twisting without fracture —its purity, uniformity, and smooth esses. silvery surface—these advantages are leading to the use of Bethanized Wire in a wide range of applications. Bethanizing permits the use of steel springs with their superior physical properties in pumps and other locations where alloys have been used. And Bethanized Wire makes pos- sible zine protection on bed-springs for ma- rine or hospital service. For telephone and telegraph service, Beth- anized Wire offers the advantage of a coat- ing that can be put on as heavy as the con- ditions call for. Higher tensile strength can be provided than is possible in wire coated by the hot-dip process. Bethanized Wire splices without surface cracks. Industrial chain-link, park, station and farm fence make full use of all of the improve- ments brought by the Bethanizing process: Heavier coatings that greatly increase life; no cracking of the coating in weaving; last- ing fine appearance. The service life of strand can be much increased by making it of heavily -coated Bethanized Wire. Thick Bethanized coatings stand being woven into strand without dam- age. Abuse in erection will not cause cracks that offer places for rust to start. Bethanized Wire, with its smooth silvery fin- ish, makes an excellent material for spokes in the wheels of baby carriages, tricycles and The fabricat- ing operations do not damage the coating. similar wire-wheeled vehicles. Wire brushes are another product in which the forming properties of Bethanized Wire have opened the way to the making of a bet- ter product with less difficulty in manufactur- ing. Large quantities of Bethanized Wire are now being used in brush manufacture. In sereen wire the heavier coatings which Bethanizing makes possible are especially useful as, under the abrasive action of the material being screened, the life of a coating is about proportional to the thickness. A 2.4 oz. Bethanized coating lasts about three times as long as the usual hot-dip galvanizing. Bird cages and other wire articles in which appearance and serviceability are important offer a broad field for the use of Bethanized Wire. The smooth bright surface of the wire results in a product of added saleability. BETHLEHEM STEEL COMPANY General Offices: Bethlehem, Pa. District Offices: Atlanta, Baltimore, Boston, Bridgeport, Buffalo, Chicago, Cincinnati, Cleveland, Dallas, Detroit, Houston, Indianapolis, Milwaukee, New York, Philadelphia, Pittsburgh, St. Louis, St. Paul, Wash- ington, Wilkes-Barre, York. Pacific Coast Distributor: Pacific Coast Steel Corporation, San Francisco, Seattle, Los Angeles, Portland, Honolulu. Export Distributor: Bethlehem Steel Export Corporation, New York. ... THE IRON AGE ... SEPTEMBER 27, 1934 | ESTABLISHED 1855 Vol. 134, No. 13 1 A Message to the Metal Congress By W. A. IRVIN President, United States Steel Corpn. Tis a pleasure to extend these words of greeting to the National Metal Congress, convening nearby in New York, and to affirm our deep interest in its proceedings. The cooperation of the | various societies and associations to make these joint meetings | possible is a fine example of the streamlining of technical effort— a kind of effort which is of vast importance to our industry. National Metal Week, with its manifold activities, rightly attracts the attention of all who are directly or indirectly interested in the progress of the technology of metals. Those who are not inter- ested are few in number. We compliment the participating groups on providing this effective forum for the dissemination of knowledge and for the exchange of ideas. Today we find metals in use on land, at sea, and in the air, performing services considered impossible in years gone by. The new order of things is due largely to the circumstance that metals and alloys are now made and specially processed to meet the particular demands made upon them. But the "know-how" and "know-why'' of present practices had to be developed by years | of arduous study and experiment in which, happily, art and science went hand in hand. The role played by the technologist has been of outstanding value, and the end is not yet in sight. Men in the modern metal industry are discussing their problems, rationally, in terms that were simply ''terms'’ a few decades ago. Now we have come to realize, thanks to the pursuit of metallur- gical science, that such expressions as grain size, metal-slag equilibrium, fatigue, and creep strength have a deep and prac- tical significance. Additional useful information will be made available during the sessions of the National Metal Congress this fall, presaging further progress, and we are glad to commend the constituent societies for their noteworthy activities. 1 A NCO W A. IRVIN, Drawn by John Frew for The Iron Age mix to e por che bei! Squ tior doe iro! tior whi cok tio 195 eco fac ove ser cal age tol mi qu an pr si in at Cc co us in combination with an air fur- nace fired with pulverized coal mixed with pre-heated air is leading to exceptional fuel economies and im- portant improvements in physical and chemical properties of chilled iron being poured at the Sacramento Square plant (Chicago) of the Griffin Wheel Co. The total fuel consump- tion including cupola and air furnace does not exceed 231 lb. per ton of iron melted. Correcting the consump- tion of coal on the basis of its cost, which is about one-half the cost of coke, brings the total fuel consump- tion on a coke basis down to about 195 lb. of coke per ton of iron melted. Ui: of the pre-heated blast cupola The importance of quality and economy to a chilled car wheel manu- facturer is shown by the fact that over 2,000,000 freight cars in active service are now equipped with chilled car wheels. Each car travels an aver- age of 10,000 miles a year, which is equivalent to 160 billion wheel-miles annually. Each wheel carries an aver- age load of 6 tons and therefore the service is 960 billion ton-miles each year. The life of the average chilled car wheel ranges from 8 to 10 years. The output of the Griffin Wheel Co. is in normal times 1,000,000 wheels annually requiring a melt of 400,000 tons of iron.. In order to meet the exacting de- mands of the railroad shipper for quicker deliveries, heavier loadings and economical service, continued im- provement is being made in the de- sign, quality of materials, and sav- ings effected in the initial and oper- ating costs of railroad equipment. Consideration of these matters led the company first to design and put into use in its plants the hot-blast cupola only to be followed now by the in- Stallation of a hot-blast cupola in combination with a hot-blast air fur- nace. This new duplex process is melting and refining 180 tons of iron lron Refined By Griffin Duplex Process By ROGERS A. FISKE Western Editor, The lron Age for the production of 400 car wheels per day of eight hours. It operates on the continuous pour principle. There is no practical reason why this unit cannot be operated on two or three shifts per day thereby increas- ing its output proportionately. High Test Cast Iron Study of the duplex process reveals that it is particularly adapted for production of high test cast iron. The air furnace has proved to be satisfac- tory either for batch production or in combination with cupola melting. The physical properties of cast iron pro- duced in the air furnace with no change in chemical composition is im- proved from 10 to 20 per cent as com- pared with cupola iron. These prop- erties are said to be due to the re- moval of non-metallic inclusions, de- oxidation and degasification of the metal. This is largely the result of superheating, which consists of heat- ing the metal before pouring to a temperature from 2850 to 2900 deg. F. Superheating produces a molten mixture that is extremely homogene- ous and free from graphite nuclei and this is said to be responsible for the FUEL consumption equivalent to 195 lb. of coke per ton of iron is secured at the Chicago plant of the Griffin Wheel Co., through the use of a pre-heated blast cupola in combination with an air furnace using pulverized coal mixed with pre-heated air The actual consumption of powdered coal, per ton of iron melted is not over 231 Ib., com- pared to from. 700 to 800 Ib. ver ton required in melting iron from cold stock in an air furnace. The Griffin Duplex process therefore represents a decided advance in fuel economy remarkable structural changes that are obtained. The structure of a ma- terial produced in the air furnace has an extremely fine grain size. This material has a much more uniform grain size than cupola iron when poured into sections of varying sizes. Heavy castings made with air fur- nace iron have a uniform grain size from the outside edge to the center, which usually results in excellent strength and uniform hardness. Cast- ings made with Sections 4 in. in diam- eter have shown exceptional uniform- ity, Brinell hardness tests at the center running less than 10 points lower than those taken at the edge of the casting. The microstructure of the air fur- nace material, due to the above men- tioned commercial improvements, con- sists almost entirely of pearlite hav- ing only a trace of cementite and ferrite. The graphite formation is finely divided and uniformly distrib- uted throughout the entire structure. It has been generally agreed that the ideal cast iron microstructure should consist of pearlite with a uniform distribution of finely divided graphite. This structure has proven to give ex- ceptionally fine physical properties. These improvements, when coupled with various combinations of chem- ical elements such as are possible to maintain and control in the air fur- nace, produce a superior product. The most essential change in chemical composition is the reduction in total carbon. Microstructural changes can be controlled more definitely with metal containing a lower carbon and silicon content. Silicon readily pro- motes graphitization and in the pres- ence of high total carbon promotes the decomposition of combined carbon. Therefore a material having a high total carbon is likelyto contain a large amount of free ferrite and irregularly formed particles of primary graphite. If the silicon is favorably low, it may The Iron Age, September 27, 1934—13 | | Deflection 0.240 0.220 Cornbustion Chamber 0.200 “ my 0.180 0.160 x ™ /2”c. | 2 9 9 5 = 2 ee SS = 8 3000 contain a considerable amount of pearlite, but the strengthening effects of this structure will be largely offset by the unequal distribution of coarse graphite flakes. The Duplex Plant The duplex plant as now set up at the Sacramento works consists of a cupola and its blast preheater, the air furnace and its air preheater and coal pulverizing equipment. The cu- pola measures 74 in. in diameter and has a melting rate of 28 tons per hr. It is served by a battery of three blast preheaters that are in series. These are made with cast iron tubes and follow the design covered in the Griffin patent 1627536, issued May 3, 1927. Waste gas from the cupola is drawn through a duct to a combus- tion chamber to which air is admitted, 14—The Iron Age, September 27, 1934 or My | As a Le 25720 4ee art | | | | 4000 5000 Transverse Strength 2 AT LEFT C ymparative leflection of air furnace and cupola irons. strength and thereby burning CO to CO, and at the same time increasing the temper- ature of the gas which passes directly into the first preheater unit. A fan connected to the last preheater unit creates the suction to draw the gas over the heater tubes. Air under pressure enters the pre- heater at the end opposite the gas inlet and after being preheated passes on to the cupola. It should be noted that the gas and air flow through the Waste Gases fram Air furnace, } ir Preheater for Air Furnace ( preheater units in opposite directions. The accompanying table indicates the economy to be realized by the use of the hot blast. Typical temperatures are: gas in combustion chamber 1700 deg. F.; gas leaving cupola 1400 deg.; gas above arch 1550 deg.; waste gas above heater 620 deg.; gas at charging door 150 deg.; and hot blast 600 deg. The blast pressure is usu- ally about 8 oz. and the suction % oz. Actual practice shows the coke required per ton of iron to be 25 |b. for the bed and 134 lb. for melting (including extra), a total of 159 lb. The air furnace stands near the cupola, the charging end being only a few feet away from the tap hole of the cupola. Inasmuch as this is a continuous process molten iron is con- ducted from the cupola to the air fur- nace by means of a clay lined trough. -Air Furnace co Tk coo Tb H Se mie: en tf i » a re. Pike — _ Si | TF Cc,> ort hes et et he bt oboe ctions., licates he use atures r 1700 1400 waste ras at t blast S usu- suction e coke 25 Ib. relting 9 Ib. ar the x only 1ole of 3 is a is con- ir fur- rough. The air furnace measures 7 ft. 6 in. the stack end. The stack dimensions wide by 40 ft. long (inside dimen- are 4 ft. 6 in. inside diameter and sions) and has capacity of 30 tons of 50 ft. high. The tap holes are on the metal. The bed of the furnace at tap same side of the furnace as is the hole is 8 ft. 7 in. above the floor level. iron inlet hole. As the iron flows along the bed or hearth of the fur- nace it travels against the flame and From bed to crown of roof arch is 3 ft. 6 in. at firing end and 2 ft. at Relative Economy From Various Degrees of Pre-Heated Blast in the Cupola Potential heat 2 WA. COMGi scce es ccveves a 3,000 B.t.u. Heat absorbed 1 Ib. iron..... eens one 540 B.t.u. DEGREES FAHRENHEIT OF PREHEATED BLAST hot gas. A trough carries the iron from the furnace to a tilting ladle. The furnace design consists of a con- crete foundation and brick side walls, and a sand bed underlies the sub-bot- tom which is covered with ganister over which is the fire brick hearth. The roof consists of a series of bungs, spares of which are prepared in ad- vance so that roof brick falling dur- ing operation of the furnace does not delay or interrupt the refinement of iron. Stack of Conventional Design 0 200 400 600 800 1,000 Pounds coke to melt 1 ton iron vs 210 182 160 145 135 128 The stack is of conventional design Ratio iron to coke............+:. , 9.5 11.0 12.5 13.8 14.8 15.6 except for an opening in its side Per cent CO? developed......... : 12.5 13.0 13.5 14.0 14.5 15.0 through which is drawn that part of B.t.u. developed per Ib. coke......... 9,580 9,810 10,040 10,270 10/500: 10,270 the waste gas which is used in the B.t.u. absorbed by iron...... Seen 5,130 5,940 6,750 7,450 8,000 8,420 ‘ ' aes si : ial “m : 7 air preheater. A motor driven fan Efficiency of cupola, per cent.... Sing 39 45 52 57 61 65 : : : Efficiency of combustion, per cent.... 74 75 77 79 81 83 is used to overcome resistance in the Efficiency of heat absorption, per cent 53 59 67 73 76 7s heater. A duct from the heater leads ase to a fan located near the coal pulver- Cupola Bungs, 4 LO oro ra ton th pp {| /\ re Tre mn dE Steeters ~ Fo%g octet ee! Oe ka Premixture.. td of Fuel and \x | Hot Air La S a nid. S . iy o: s x Sateen seeereiene-tepoy 9 0.80. ps? a9." 4 Db: (2 ob ee Pee pes > ote Tp e: COCO rr bot ah | Latin The Iron Age, September 27, 1934—15 r Inlet Pe pa oe Pu VERIZED fuel mixed with preheated through two burners tapped to a Du 16—The Iron Age, September 27, izer. Part of the hot air is drawn through the fuel pulverizer for its scavenging action. The air ladened with pulverized coal leaves the pul- verizer and is mixed with the addi- tional preheated air needed for com- bustion and the mixture is sent on its way to the two burners on the air furnace. The rate of fuel prepara- tion and the mixture of fuel and air are under manual control. No addi- tional air is admitted to the furnace at the burners. The fuel used comes from Eastern Kentucky. Its analysis is approximately 14,400 B.t.u., 4 per cent ash, 35 per cent volatile matter and 1% per cent moisture. Temperatures are as follows: iron at cupola spout 2700 deg. F.; iron at air furnace inlet 2650 deg.; iron at air furnace tap holes 2850 deg.; and air blast 350 deg. Temperature of iron poured into wheel molds is 2570 deg. F. Temperature of waste gas entering preheater 1220 deg. Iron melted in the cupola is con- veyed to the furnace by continuous tap and slightly more than one hour is required to fill the furnace after which it is continuously tapped ‘at the rate of 28 tons an hour. This means that the iron remains in the furnace one hour during which time its tem- perature is raised 200 deg. to 2850 deg. F. The total carbon is slightly reduced (20 to 30 points) and any desirable modification of analysis can be made. There is practically no sili- con loss in the air furnace. The com- bined silicon loss is 16 per cent. The two-fold purpose of the air furnace is complete control of the temperature of the molten iron to in- Record of Fuel Consumption ab. Cupola—Coke SRS faeces a diene wae ee ea 4,400 First charge of coke...... at 1,100 | ee eg ee eherd 5,500 Coke between iron charges 950 Ib. Air Furnace—Coal For preheating furnace to time of first tap, 2 hr. at 2000 Ib.. 4,000 For preheating iron, 6 hr. 30 min. at 1500 Ib........ ee 9,750 EEE. Virdsa GNU Re eer -.- 13,750 Fuel Consumed Per Ton of Iron Melted— SUNN, ois ela xe dees 124 Bed and preheating cupola.... 25 Fb oad inset veo ek ee ee 149 Air Furnace—Coal POl Pe a keciseced: ; 50 For preheating furnace..... ; 22 EE baw e cada a comes 72 221 Grand total (149 plus ee ae sure liquefaction of the carbon in the iron, and secondly, to completely con- trol the percentage of total carbon in the iron at a predetermined amount, which cannot be done in ordinary cupola practice. The 30-ton air furnace and pulver- Coal cror S trom ized coal firing equipment were fur- nished by Whiting Corpn., Harvey, Ill. The firing equipment consists of a Whiting air separation, impact type pulverizer, a cast iron Clarage ex- hauster for furnishing combustion air, and special pulverized coal] burn- ers with water cooled nozzles. This is a direct fired unit in which the coal is blown directly into the furnace immediately after pulverization. It uses air which is heated to a temper- ature of 350 deg. F. With this new development it is possible to grind coal so fine that 98 per cent will pass through a 200 mesh screen, and by an overhead bunker to the puiver mixed with preheated air. Pulverized coa simply resetting a control this fine- ness can be changed so that only 35 per cent will go through the same screen. The air preheater was built by the Air Preheater Corpn., Wells- ville, N. Y. Fuel consumption on this unit over wie 5 er where if is stored aN > a a period of 10 days and a melt of 1800 tons averaged 73.2 lb. of coal per ton of metal melted. Taking into consideration the complete unit, that is cupola and air furnace, there are available the accompanying records of fuel required for melting and re- fining 180 tons of iron. Results heretofore attained in melt- ing iron from cold stock in an air furnace require from 700 to 800 Ib. of powdered coal per ton of iron melted. The Griffin duplex installa- tion therefore makes a decided ad- vance in the economy of fuel for melting and refining iron. The Iron Age, September 27, 1934—17 | Shot Weld—A Closely Controlled Weld LL the world has heard of “shot weld” and its application in the fabrication of stainless steel for light weight railroad cars, truck bodies, aircraft structures and ship parts. To the layman it implies, per- haps, a mysterious new method of welding. It is a high speed spot weld- ing operation according to a new method which produces, in the ma- terial being welded, certain desirable metallurgical and physical charac- teristics. As applied to austenitic stainless steel it produces strong duc- tile welds having good fatigue values, leaving the entire structure free from deleterious carbide precipitation. Its application to date has been largely in the chrome nickel group of stain- less steels. While the control of spot welding is a very desirable procedure, ordinarily, a wide range in the variables is per- missible, and this latitude will not materially affect the quality of the re- sultant weld. For example, in weld- ing ordinary mild steel it is entirely feasible to use lower currents pro- 18—The Iron Age, September 27, 1934 By W. SPRARAGEN President, Spraragen Engineering Corpn., New York viding the time of welding is corre- spondingly greater. According to the new method, on the other hand, in corrosion-resisting steel and partic- ularly in the so-called 18-8 group, the reverse of this is true. Here every element is controlled within narrow ranges in order to obtain the results at which the method is aimed. Duration of Welding Cycle In welding stainless steels by the resistance method, the duration of the welding cycle is not any longer than necessary and not so long that a criti- cal zone is formed next to the weld, which may later result in intergran- ular corrosion. The time cycle of the ing Process “shot weld” varies from % to 18 cycles of a 60-cycle current, depending upon the thickness of the material and the size of the spots. I’Rt in general represents the con- trolling elements although, of course, there are other variables which direct- ly or indirectly affect each of these items and, in turn, the quality of the weld. For example, the amount of current, J, would be dependent on the thickness of the material and the di- ameter of the electrode used. It might, in some cases, be affected by the ca- pacity of the machines doing the work. R, which represents the resistance, would be dependent on the thickness of the material, the number of thick- nesses placed together, the size of the electrodes and the mechanical pres- sure. Again, it would be dependent upon the proximity of completed spots. T represents the number of cycles, which, as stated above, varies from % to 18. A little later on there are given some actual values which are used in practice. In order that the spot shall repre- Cc T som diff lim Li — So ma: and req Is | 18 ng al sent a balance in strength between its shear value and the strength neces- sary to tear the spot out of the ma- terial, a diameter of electrode is usual- ly selected of four times the thickness of the plate. The tip is somewhat rounded. If too large an electrode is selected, there is a tendency for arc- ing action to continue until the tip of the electrode has been worn or built up to approximately the diameter in- dicated above. One would probably expect that because of the high resistivity of stainless steel and its relatively low specific heat, currents would be used of a value 25 per cent less than that used in welding of ordinary steel of the same thickness. On the contrary the welding current is very much greater indeed, but applied for a very short time only. Control Apparatus Set Frequently To the layman control may appear somewhat complicated and apparently difficult to keep within the required limits. Actually, the control is set so as to produce a weld which has maximum shear and ductility values and which meets certain metallurgical requirements. The shearing strength is actually determined by pulling a co weight construction today means usually the wise use of superior materials. Among such are the corrosion-resisting steels They allow for reduced weights because of increased strength. In building passenger cars of the Stainless steels, the material is used in part in strip form, and in the assembling spot welding under notably close control is employed. On this so-called shot-welding process Mr. Spraragen here sup- plies some facts and figures. specimen and the ductility by a twist test. The weld penetration is actually determined by examining an etched section under the microscope. If more than two thicknesses of material are to be joined the weld penetration is from 50 to 70 per cent of the thick- ness of the outer plates. If, as is usually the case, two thicknesses are joined by a spot, the weld penetration in both plates is from 50 to 70 per cent of the thickness of the plate. If it is more than this amount, the heat of the welding will destroy certain de- sired properties in the stainless steel. If it is less than this amount, the shearing and fatigue values are not likely to be all that are required. Should these test specimens not come within the required range, ad- justment in current or pressure is made or the electrode is trimmed down more carefully. If the specimens meet the metallurgical and physical require- ments the machine is set. The control mechanism used in the Budd plant is mounted in a box as shown in the accompanying illustra- tion and a record is made of each spot. A synchronous motor with a suitable gear ratio drives the electrical and mechanical control for the timing cycle. Adjusting taps in the primary of the welding transformer control the welding voltage and hence the welding current under the given con- ditions. The result is indicated by a line drawn on a roll of paper. The line must fall within two vertical lines provided on the paper. Should it fall on either side, a bell rings au- tomatically and the operator or in- spector knows that a _ significant change has taken place in the welding conditions requiring a readjustment of the equipment to continue making satisfactory welds. This change as well as the original setting is de- Welds in Stainless Steels of 0.012-in. Thickness Strips Overheated weld, a case of too much fusion. Insufficient fusion, giving a semi-fused weld. Insufficient fusion, or cold weld. Shot weld with cor- rect fusion. The Iron Age, September 27, 1934—19 i q I ——ee eee ee ee eee eee eee ee ee ee me termined by physical and metallurgi- cal tests indicated above. Of course, this device cannot direct- ly record a change in mechanical pres- sure applied to the electrodes, but the change would affect the resistance, which in turn would affect the amount of current and this of course is re- corded. When intelligently used this re- corder and signalling apparatus in- sure the predetermined quality of The control mechanism is mounted in a box and a record made of each spot. 20—The Iron Age, September 27, 1934 each spot. This is highly important in many structures such as aircraft parts where the strength of important joints is dependent upon single welds. Shot Welding of Stainless Steels This shot-welding method greatly expands the fields of use of stainless steels. The applications have been applied in a wide range in the case of the austenitic nickel-chromium alloy steels, those of 150,000 to 200,000 lb. per sq. in. tensile strength, or the so- called 18 and 8 with carbon below 0.16 per cent. By reason of their attainable strength and resistance to corrosion, these steels lend them- selves admirably to structural uses and especially in structures which are exposed to the weather or sub- jected to considerable vibrations, and more especially where great strength with minimum weight is an important factor, as in aircraft structures. These steels also have the valuable property for some structural uses of be- ing substantially non- magnetic. The resistance weld- ing of this cold worked steel by ordinary means is hazardous for the following reasons: First, because the steel is annealed when air Stainless steel mem- bers are fabricated by the Budd shot-weld process. Side frame unit being assembled. i ae cooled from a temperature below its melting point. If too much of the area of the steel is allowed to become annealed it weakens the structure at the joined areas. Secondly, because there is a temperature range within which, if the steel is allowed to re- main there for an appreciable time, carbide precipitation will occur. This carbide precipitation will result in destroying the resistance of the metal to corrosion as well as its homo- geneity. These latter features are true as to both the cold worked and the annealed stock. Annealed 18-8 stock, which has an ultimate tensile strength of 90,000 lb. per sq. in., wili be subjected to car- bide precipitation if heated within the range of 1100 to 1400 deg. F. for an appreciable length of time, and intergranular corrosion will follow. In the ordinary spot weld process, some of the metal surrounding each weld is subject to this attack. Necessity for Careful Control The electrical resistivity of the 18-8 stainless steel group is about six to ten times that of carbon steel. There is also the added difficulty of a much lower heat conductivity and a larger coefficient of expansion than with ordinary mild steel. All of this re- quires careful control of the welding heat to prevent too long a dwell in the undesirable temperature range of the metal. A shot weld aims to utilize very large welding currents in a small frac- tion of a second. By taking into ac- count the relatively low melting point of stainless steel (about 2500 deg. F.), its high electrical resistance, its poor heat conductivity and the fluidity im- mediately upon fusion, the weld may be suc act pal tha ove me str isti por : the rie e. bot thi or pli me TI fo im an to nem- ed by -weld frame bled. y its the ‘ome e at ause ithin » Te- ime, This t in 1etal omo- are and s an 0 lb. car- ithin . for and llow. cess, each 18-8 x to here nuch rger with ; re- ding 1 the ' the very frac- » ace point F.), poor , im- may be made in a brief period of time in such a way that the desirable char- acteristics of the metal are not im- paired. Tests have actually shown that with welds made in this way the over-lapped welded portions of the metal possess substantially the same strength and anti-corrosion character- istics as the metal remote from such portions. Stating the matter in another way, the welding operation should be car- ried out in such a manner as to insure a steep heat gradient in the metal both on the rise of temperature and on the fall of temperature. In this way the heat which has a deleterious effect upon the steel is limited both in degree and time of application, or amount to not substantially more than necessary to effect the weld, and therefore it will have a minimum ef- fect in impairing the desirable char- acteristics of the metal. A rapid rate of introduction of the heat, i. e., the steep heat gradient on the rise, will be effected by utilizing the relatively large currents for the brief period of time, and the rapid fall of tempera- ture, i. e., the steep down gradient, will be effected both by the rapid in- troduction of the heat and by utiliz- ing not substantially more heat or energy than necessary to properly weld the metal, thus enabling the metal to be more quickly quenched by the conduction of the surrounding cool metal and the electrodes. The electrodes may be water cooled if de- sired. If the heat is relatively slowly introduced the metal surrounding the weld would not remain cool and would therefore be less effective in quenching the metal of the welded zone. Also, other factors being the same, the more heat or energy put into the weld the more time required to quench the metal. Deleterious effects resulting from the introduction of an excess of heat or undue dwell of the heat may take place without being detected from the mere appearance of the welded zone. They may only be discovered by microscopic examination or by tests for strength and corrosion, so it is important to regulate properly and accurately both the amount of current and the time of application thereof to insure uniform and reliable welds. Pressures used in spot welding of the stainless steels are necessarily very much higher than for the same thickness of carbon steel. The plates are of course much stiffer and these high pressures are necessary to insure good point contact. Although the metal has not been molten for more than 80 per cent of its thickness, some discoloration is visible at the small CURRENT REQUIREMENTS FOR DIFFERENT GAGE MATERIALS Example A Example B Example C Gage—2 thicknesses, each, in.......... 0.010 0.030 0.050 Diameter of electrode, in.. ee 3/16 % My Area of resulting weld, sq. in.............. 0.00165 0.0143 0.0143 Total electrode pressure, Ib.. Pe cack se We we wees 75 500 500 Welding time, sec........ eeePeawess scent 0.0083 0.0583 0.0833 Weldings current, Gs d6 60 heen ei die dee 1,472 4,415 4,270 Current density in welded area, amp. per sq. in 893,000 308,700 298,200 surface area where the electrodes have come in contact with the metal. This discoloration in no way affects the properties of the material. The accompanying tabulation will illustrate some instances of the process applied to spot welding of cold-rolled austenitic stainless steel. The current values are given in terms of the density per square inch of area of the welds themselves (measured transversely of the direction of cur- rent flow). The sizes of the welds for given electrode diameters may be varied by varying the current density and time. The electrode sizes are varied largely to accord with the di- mensions of the work being done, e.g., thickness of gage, stiffness and rela- tive alinement of parts, pressure need- ed to draw them together, accessi- bility to the spot to be welded, etc. In the welding of stock from 0.008 to 1/16 in. the diameters of electrodes have varied from about 3/16 to about % in. The weld areas were measured mi- croscopically after sectioning, polish- ing and etching. An Application in Light Weight Cars Through the use of shot welding of stainless steel it has been possible to build a car of the weight of 250 lb. per passenger. A good example of this is the Budd built and General Electric equipped five-section car for the Brooklyn-Manhattan transit company. But the weight saving by mere weight reduction is not to be confused with true light-weight construction. The first accomplishes the end at a sacrifice of strength and security; the latter, by proper portioning of loads to ma- terials, can actually increase the fac- tor of safety after a very substantial lessening of weight. This involves an effective use of superior materials. |IDDLEMAN between mountain of ore and mechanization is the open hearth from which comes the preponderant share of America’s steel. So true is this that the state of business throughout our coun- try can be roughly but surely measured by the reflections from these hearth fires As the blast furnace typifies iron open hearth typifies stee! the The Iron Age, September 27, 1934—21 ; | | | : NEW rolling mill recently in- stalled by the American Brass Co. at its Canadian plant, Anaconda American Brass Ltd., New Toronto, Ontario, is decidedly novel both as to methods employed and equipment used. Following some- what the practice instituted by Hirsch in Germany and Imperial Chemical Industries Ltd. in England, this mill is designed for rolling strips of much greater weight than have here- tofore been rolled in American brass mills. The weight of the slabs is such that a furnace charge of 850 pounds will fill either one or two molds, while the width of slab is determined by adding together the width of the narrowest and widest bars previously rolled in single strips by any particular mill. In the Canadian mill described, a standard width of 18% in. has been adopted, being a combination of 3 in. and 15 in., and it will be readily understood that this slab will produce a 4 in. and 14 in. strip, a 6 in. and 12 22—The Iron Age, September 27, 1934 verhauling follow tt break-down de vered Dy crane t the 4-high mill in this «picture in. strip, or any other desired com- bination down to two 9 in. strips. In using such a combination strip, the mill tickets are first sorted as to mixture and then sorted by widths, and, starting with the widest width the mill clerk orders from the cast- ing shop a sufficient number of slabs to fill his wide metal orders, making note of the width and number of selvage strips resulting, and, after all orders for metal over 9 in. wide have been filled, the narrow metal orders are filled, using first the sel- vage strip and then an additional number of castings. Use of Selvage Strips As narrow metal orders always greatly exceed wide metal orders in American and Canadian mills, the selvage strips can always be .used immediately if desired but in actual practice it is found preferable to keep a certain number of these strips in stock as they are most useful in fill- ing small orders promptly, while Canadian Brass Fig. 2—Annealing and afte which the bars are chowr metal for narrow orders can be rolled in multiple widths with greater economy. This practice has many advantages starting with the casting shop; the number and cost of molds is reduced to a minimum, it speeds production and shortens delivery because strips of any width can be taken from the selvage pile or slit off a wide bar without waiting for castings, it re- duces end and slitter scrap materially and it greatly simplifies mill account- ing as the weight of every bar is identical per inch of width and the length of every bar is the same at any specified gauge, regardless of its width. While brass mixtures commonly used abroad permit hot rolling with economy, this is not always true in the United’ States and Canada and the new Canadian plant is equipped with both hot and cold breaking down mills for rolling strip metal from cake or casting down to 0.400 in., at which point it is overhauled and then cold rolled to finish. The Hot Mill The hot mill is of standard 2-high type with rolls 24 in. x 72 in. driven at a speed of 280 ft. per min. by a 500 hp. motor with flywheel. This mill is equipped with live roll lifting table in back, a motor driven edger mounted on a car to slide sideways into and out of position in front of the rolls, and a swinging conveyor table to convey cakes from the heat- ing furnace to the left hand side of the rolls invariably used for the first heavy roughing passes or semi-fin- ished strips to the edger and the right hand side of the rolls reserved for finishing passes where good sur- face is necessary. This mill is used principally for rolling copper, bronze and Everdur from cakes weighing 400 and 600 Ib. to strips from 18 in. to 24 in. wide and serves both sheet rolls of stand- ard ty mill te The featur a min deseri of st equip! will Sta slabs high shear for si Thi type, elevat are | pushe in tu to bri shear shear toa back fallir into At mour $5 Rolling Mil rolled reater ntages »; the «duced uction strips m the e bar it re- rially count- ar is d the me at of its monly with ue in . and ipped down from n., at then -high riven by a This fting edger ways nt of veyor heat- le of first i-fin- the rved sur- - for rdur ard type and the large 4-high strip mill to be later described. The Cold Rolling Mill The cold mill contains many new features for handling heavy bars with a minimum of effort—which will be described in detail, while description of standard rolling and finishing equipment, familiar to all mill men, will be purposely omitted. Starting from the casting shop, the slabs or bars are piled eight or ten high and carried by crane to a gating shear where the metal is inspected for surface and interior soundness. This shear, of standard guillotine type, is equipped with a hydraulic elevator in front on which the bars are placed by crane, a pneumatic pusher engages the back of each bar in turn, and, as the elevator is raised to bring the top bar slightly above the shear table it is pushed first into shearing position and then back on to a roll table extending horizontally back from the shear, the gate end falling through a slot in this table into a scrap bucket. At the rear end of this table is mounted a car designed to straddle a AAA Fig 1—The cold breaking-down mill is of 2-high type and runs at 112 ft per min. Pneumatic pushers load the rolls trom slab stacks and also pile rolled bars into delivery cars By JAMES R. COE Mechanical Superintendent, American Brass Co. DVANCED practice in brass rolling is represented in the methods and equipment employed in the Canadian plant of the American Brass Co., Anaconda American Brass Ltd., New To- onto, Ont The mill is designed for rolling strips of much greater weight than have heretofore been rolled in American brass mills. Large econ- omies have been secured through ingenious adaptations of English and German methods in combina- tion with original developments by the American company’s engineers heavy base and run back on slightly inclined tracks extending from the sides of the base. This car carries a single idle roll level with the roller table to support the front end of the bar and a bumper plate to engage the bar, forward motion of which pushes the car back up the slightly inclined tracks until the back end of the bar leaves the roller table when the front end slips off the idle roll and the bar falls horizontally on to the base to form a new pile while the car returns by gravity to starting position. The breaking-down mill for cold rolled metal is a standard type, 2- high mill driven at a constant speed of 112 ft. per min. by an 800 hp. motor. Represents Advanced Practice This mill is equipped with a motor driven roller top elevator on which piled bars are loaded by crane and advanced by a pneumatic pusher until the pile abuts against an apron at- tached to the guide table in front of the mill. As the elevator is raised the top bar is pushed off the pile and into the rolls by the pusher, the front end of which carries a hinged slipper resting on the bar while the heel en- gages the back end of the bar. Leaving the rolls the bars pass over a driven roller behind the rolls and fall on to a smooth top table where an operator merely sees that they pile properly, and after two piles of castings have been passed through the mill and stacked into one pile a pneumatic pusher pushes this pile sideways on to a car and against a bumper which alines all the bars perfectly. > ‘ef. lit 7 - can 7 a hie ld ee : : : 7 ; 7 - PJ “ —— - . _— * rd The car is then transferred to a which again transfers the bars side- position in front of the rolls between ways to the elevator in lowered posi- the elevator and a second pusher tion. After two or three piles have been passed through the mill, the rolls are adjusted for the next pass and this entire operation is repeated until the bars have been reduced from 2% in. thickness to 0.400 in., seven passes and one anneal being required. Annealing Furnace Leaving the breaking-down mill at one inch thick and 0.400 in. thick the bars are placed by crane on anneal- ing pans and passed through a nar- row tunnel type furnace in which one chamber is heated by oil burners while a preceding chamber is heated by waste gases from the first men- tioned chamber. Leaving the furnace the bars pass through a cooling chamber in which is mounted a large number of nozzles through which water is_ sprayed against the metal, which water is immediately transformed into steam and the metal cooling in this atmos- phere is practically bright and re- quires no cleaning. After the second annealing opera- tion the bars are passed twice through a milling type overhauling machine in which about 0.010 in. is removed from one surface at each pass. This milling operation is always performed on the lower side of the bar in order that chips will fall away from the cutter and not be rolled into the sur- face of the metal by the powerful Th mill 200 f In fr moto! and that secon sticke Th for t passi a st mati a m strais provi in. it At coils seco! thro an 0} end i rotat end : wood end genti dista into Af trans front the r that then coil s Th conné faste thro ama moti mati car half signe ered flat 1 ered being a sh on t when way way Wi the I are | liona feed rolls necessary to pull wide metal through the machine. After overhauling, the bars are in- spected for perfect surface and then are delivered by crane to the big 4- high mill. The Big Mill » This mill is a 14 in.-32 in. x 48 in. rst pas mill driven at a constant speed of through 900 ft. per min. by a 750 hp. motor. re In front of the mill is located first a das motor operated roller top elevator oiler and a pneumatic pusher similar to ejected that on the breaking-down mill and, s oe second, a special guide table and oils sticker for coiled metal., The elevator and pusher are used ” for the first pass of flat metal which, passing through the rolls is coiled on a standard 3-roll coiler with pneu- matic ejector which delivers it on to a motor driven conveyor running » straight back a sufficient distance to ae D bee 1 ee of the transfer station, at which the open é : a ae g machine is located. Here the coil is pneumatically clamped and provide storage room for 25 coils 22 a a4 end straightened tangentially by a piston operated puller in. in diameter. Se of the elevator and when rolling mounted between the roll housings to steak auiaieh . eames eel coiled metal, with the elevator in hold the metal and force it into the eseats ‘am eneinn saan Ae lowered position, forward motion of rolls, at which time the ends of the in ebdiaien. netudtn. ties ae aaa the cot car with peg in position first shaft supporting the horn engage ed in on. ton, demenn tn ool oantaal turns the end down into horizontal heavy bearings on the roll housing whetion, end then. pulls. ont. te wall position between side guides of the and prevent the coil being pulled into : second car and then pushes the sec- the rolls. e rolls end and irons this end down over a ond ear end sented inhe the voll. the T or ; Ss and wooden form of such shape that the : ; its : etemmate frequent changes in | until “al wham. eitenaed all: ancieak: tee. peg passing under an idle roller roll adjustment, metal is preferably m 2% gentially from the coil a _ sufficient passes distance to permit sticking the same into the rolls or slitter. After straightening, the coils are cient transferred back to a _ position in ill at front of and slightly to one side of Fig. @—At the returr ck the the rolls where another operator sees - = a pa ash: one that the end is standing upright and sellin rots olen — then pushes the coil sideways into the coil sticking machine which coil sticking machine. bobbin urners This machine consists of two cars heated connected by drag rods: permanently vvv - men- fastened to one car and _ sliding through lugs on a second car in such Ss pass a manner that forward and backward which motion of the first car by a pneu- nozzles matic cylinder will cause the second prayed car nearest the rolls to move only ter is half the distance. The first car de- steam signed to straddle the elevator in low- atmos- ered position carries side guides for nd re flat metal and a removable brass cov- ered wooden peg when coiled metal is opera- being rolled. The second car carries rrough a short side guide table and a horn achine on to which a coil of metal is pushed moved when the first car and peg are pulled This way back and the second car part formed way back. | order When rolling flat metal, first pass, mm the | the peg is removed and both tables ne sur- are pushed forward forming a sta- werful tionary guide for the metal in front —e Fig. 7—The carriage of the coil sticking machine is next advance Pe ee entering the coil end into the rolls for the second pass rolled in batches of about 50 bars and four passes are required to effect a reduction from 0.380 in. to 0.060 in. with one intermediate anneal at 0.180 in.