The Iron Age 1926-07-08: Vol 118 Iss 2

Notice— You wiht Fined f‘convenient summary t Engin. of the week’s news on the orange- bordered editorial page. SUpeUONOGEREEOOEADEGEOEOEEEEGUGUOODROEDOGEOUOEOEEEOEDEOEOEORULOEDEUEOROROGUEOROROEUDORIEOROGUEUDEOUREGUDEGEDUDESAOOREEEOOGRLED EAE EOSOSORUDURGRORUSERSGHUEOECHOUODODUEDEOEEEOOOROROGOSOEOEOGIOLELOUSAGRERORONOROROHGDODORIOOSOONOLSOOUSEOEOEDEOROROGOSDOOGOSUSUOECSOOOOREGOUROSEGEOUREGESORESEDEDEGEO ORDO AOEOSROESEOU DORE SEReROEOENERSOnOOES : NEW YORK, N. Y., JULY 8, 1926 Single Copy, 25 Cents TTY _ Entered as second-class matter June 18, 1879, at Post Office Six Dollars a Year in U. S. _ pre at New York under the Act of March 3, 1879 Canada $8.50; Foreign $12 E bring our ULTRA SUPERIOR SWEDISH STEEL (tempered or an- nealed) over 4,000 miles to enable us to give warehouse service and furnish you a quality of Steel fine enough to justify its use where you need the best the world can produce. Ultra Superior Swedish Steel MADE IN SWEDEN BY UDDEHOLMS CO. LTD., AT MUNKFORS WORKS WARD WAREHOUSES BOSTON PHILADELPHIA CHICAGO NEWARK CLEVELAND DETROIT IRON AGE July 8, 1926 Courtesy Great Northern Railway _ + Fa V¥ a Ws AR into the north woods crowded to the limit with true with their clear, shining enjoyment, free from all shop waters of deep, blue lakes worries. framed by forests of pine, or following a turbulent trout structions, leave orders to call stream whipping. the pools on Ryerson when steel is where the big fish lie in wait. needed and thus eliminate all Wherever you go, may every thoughts of uncertain or de- hour of your vacation be _ layed shipments. When giving your parting in- JOSEPH T. RYERSON & SON we ESTABLISHED 1842 PLANTS CHICAGO ST. LOUIS DETROIT NEW YORK MILWAUKEE CINCINNATI BUFFALO BOSTON REPRESENTATION IN DENVER LOUISVILLE SAN FRANCISCO JERSEY CITY MINNEAPOLIS TULSA HOUSTON LOS ANGELES NEWARK RYERSON STEEL SERVICE ESTABLISHED 1855 THE IRON AGE New York, July 8, 1926 VOL. 118, No. 2 Spheroidization and How It Occurs Damascus Metal a Remarkable Example—Relation to Grain Growth and Grain Boundaries—An Explanation of Stead’s Brittleness BY ARCHIBALD ALLISON HE breaking up of pearlite by annealing and the ([" ctobutarization of carbide have been investigated by Tchernoff, Belaiew, Stead, Howe, Desch, and others. Under a prolonged annealing, near the critical point, the laminae of carbide have a tendency to break up, and their shape alter in the ultimate erection of spheroids. In massive specimens the process is difficult to bring about, except by very long annealing at tem- peratures fluctuating just above and just below the critical point. This is in the absence of strain. Damascus Swords and Spheroidization The Damascus swords and daggers investigated by Tchernoff, and before him by General Anossoff, from 1820 to 1831, were remarkable examples of the utility and beauty produced by spheroidization of cementite. Anossoff confirmed by experiment that the old Indian steel was produced in crucibles, either direct from the ore, or by melting iron with charcoal and, after pro- longed fusion, allowing the furnace to cool down, so that a very coarse crystallization of the mass was de- veloped. The ancient artificers having, possibly, very inefficient means of heating and forging or, by experi- ence, learning the correct temperature to avoid re- dissolving the cementite, produced by prolonged labor blades with great beauty of pattern, together with re- markable efficiency as weapons. The Damascening is thus compounded of massive cementite spheroids produced by the slow cooling from fusion, together with finer spheroids from successive heatings and hammerings. Incidentally Anossoff, about 1831, examined his specimens with a microscope to de- termine the quality of the pattern. mechanically broken by strain since, when alternate plates of lead and thin glass are arranged together, it is possible to bend the composite considerably without injury to the glass. The analogy is imperfect, however, since in the process of straining a crystal aggregate there is inter-crystalline strain as well as intra-crys- talline; that is to say, there is adjustment of the ex- ternal shape of crystals to accommodate the varying resistances to stress, due to different orientation. In straining steel by wire drawing, cold rolling, or even in finishing by hot rolling below the critical point, the strain is severe by reason of its complexity. Hence it is reasonable to conclude that the spheroidization of carbide commences with mechanical rupture of the laminae, although this is difficult to show microscopi- cally since the pearlite grains are oriented at random, with corresponding variety of resistance to stress and slip. Coalescence of Spheroids Once spheroidization has commenced, not only do repeated strainings and annealings continue to break up any pearlite grains which have resisted divorce, but also coalescence takes place between the spheroids, re- sulting in the production of a coarser size. This coalescence is undesirable, since the larger spheroids are more difficultly soluble, in the event of heat treatment being required; and hence, to obtain a full hardening effect, a longer time of heating and higher temperature are necessary than are desirable, or even practicable, with some small articles. With a cold-worked steel, the temperature of annealing need not be so high as the critical point, As to the commencement of thee )./‘)}/..auuumisim iG O@oim©2’mnu©Im, 9 and in fact a lower temperature is LL 7 divorce of pearlite, it has been suggested that the laminae are not desirable from the point of view of avoiding coalescence of the already HIS article represents labor and research of considerable dura- Fig. 1—500 Diameters . tion and is a distinct contribution to one phase of steel production. The author is chief of the research department of the J. J. Habershon Co., Holmes Mills, Sheffield, Eng- land, an old established producer of hot and cold rolled strip and of sheet steel. He is a university trained man, all of the past 20 years having been spent in the steel busi- ness, most of it with Cammell, Laird & Co. UUNOULPALDSUTLAUONGTOONNNLANRNNLONESOQUARGYSUNSH4000ET LY OPOAPTPREOANAD ENE SSERUAAOD OER OOGL A2OU 0° UMN LPONN ALES OUT OTNe tT EERAAT 73 Fig. 2—500 Diameters cy ros ree ag ER Ee I a a a al eS oe ere wa mw ig Peek a en — 74 Fig. 3—500 Diameters formed spheroids. A higher temperature will of course result in the reformation of pearlite, and that of large structure, resulting in very coarse spheroidization by later processes. Figs. 1 to 6 show microstructures of various phases of spheroidization in hard steel, all at 500 diameters. There appears to be no deviation from ordinary physical laws in the process of spheroidization. Once the carbide laminae are ruptured by stress, the frag- ments under annealing naturally tend to round off corners, and gradually move toward a spheroidal shape, - surface tension being also a factor. Probably, also, there is some effect produced by the ferrite which will now be considered. When a very mild steel is strained slightly under os- cillating stress, for example, it has been shown by Doc- tor Hanson that, in the crystals toward the junctions, there are dark marks produced which ultimately develop into slip bands and finally fracture. Fig.7 shows lines produced by straining in a material already of very coarse grain size. There has been much discussion as to the visibility under the microscope of slip ‘bands, and still more as to why, if one part of the crystal slips along a natural cleavage plane, it should still adhere to the other part of the crystal. It has, how- ever, been shown by Doctor Desch and others that, on annealing at a low temperature, the bands resume a definitely crystalline structure of very small size and, on further annealing at a higher temperature, these small crystals possess an extraordinary capacity for growth, so that very large crystals may be produced. Growth of Crystals As to the mechanism of slip, there seems to be no reason to doubt that, along the gliding planes, the material actually becomes liquid momentarily, in a parallel way to oxyacetylene cutting, or electric spot welding, in which liquid metal and cold metal exist almost side by side for a short period of time. In the cold working of steel, the liquid planes are so thin that the remaining mass of relatively cold metal acts as an immediate quenching, semi-quenching or regelation. This does not mean that the resulting material of the slip band is amorphous, but microcrystalline or ultra- microcrystalline. Naturally a highly quenched material, which has Fig. 10—1 Fig. 9—300 Diameters THE IRON Fig. 4—500 Diameters 00 Diameters July 8, 1926 AGE had no opportunity of attaining crystalline equilibrium, on annealing tends toward large stable crystals as far as the temperature and time of annealing permits. That crystals appear to grow at the expense of other crystals without any apparent law, since small crystals may devour large ones and vice versa, may possibly be explained in some such way as the following: The straining of the steel produces slip bands of micro- crystalline material, and a distorted atomic space lattice in the remainder of the material of each crystal, that is, in the blocks which have slipped along the cleavage planes. Each crystal is then a composite of new microcrystals of undistorted lattice, together with masses of old crystals with distorted space lattice. The former have at hand, as it were, suitable material for growth. This is quite parallel with the growth of living creatures, which, with suitable material and environ- ment, may grow to large size. In the case under dis- cusion the environment is provided by the raising of the temperature to the requisite point. A noteworthy characteristic of the microstructure is the production of island crystals. Figs. 11 and 12 are typical examples of a crystal within a crystal. It is true that in some cases these may be true islands, or peaks of submerged crystals, but from the frequency of their occurrence, and the general char- acter of grain growth, there can be little doubt that in many cases a nucleus preserves its individuality amid atomic movement which results in a completely envelop- ing crystal. Stead’s Brittleness The number of slip bands, or nuclei, depends on the amount of cold work or strain, and hence, if unit mass or volume be divided into crystals growing from few nuclei, the grain size will be large; if the crystals result from many nuclei, the grain size will be small. This occurs if the temperature and time of annealing have been sufficient, since it is possible to anneal a slightly strained material at a low temperature, under 600 deg. C., without obtaining large grains while, with a severely strained material, an excessively large grain size is not produced by long annealing at 750 deg. C. from the larger number of nuclei in competition for the available material. Fig. 11—100 Diameters Fig. 6—500 Diameters The extraordinary phenomenon known as Stead’s brittleness forms the link between spheroidization of carbide and grain growth. Doctor Stead showed that mild steel plates, on annealing, sometimes developed extraordinary brittleness. With a carbon contents of 0.20 per cent or less, the plates would not stand bending and gave very little elongation. The grain size was very coarse and, if the material was slightly strained by being bent or shaped in the cold, the steel could easily be broken with a hammer, and would not bend at right angles without cracking. Figs. 7 and 8 are such examples. Doctor Stead suggested that the material under such conditions failed along cleavage planes. This 1s doubtless correct, but it does not entirely account for the phenomenon. Grain growth is always accompanied by a greater or less degree of spheroidization of the carbide. The grain growth of the ferrite crystals ex- tends to the ferrite of the pearlite, and the carbide is expelled to the crystal boundary where it is grouped, not in granules or spheroids, but in spidery or flora! shapes actually dividing crystals. This form of car- bide occurs usually in steels annealed after slight straining. Figs. 9 and 10 illustrate “spidery” or “massive” cementite. With fairly severe straining the carbide is frequently in the form of granules, which may or may not be intercrystalline. A notable exception occurs in severely worked sheets which contain segregated portions. In such steels the carbides may be intercrystalline, and abnormal gram growth may occur in patehes or even on one side only. Figs. 13 and 14 illustrate patchy grain growth on one side only of a sheet. Intercrystalline Cementite Intercrystalline cementite must of necessity be an important contribution to mechanical weakness. Large crystals of soft material, interspaced by spidery shaped plates of intensely hard material, constitute a struc- ture obviously unsuitable to withstand any variation of mechanical stress. Parenthetically it may be said that intercrystalline cohesion does not require the existence of intercrystalline cement, since it may well be ac- counted for by atoms being common to the space lat- tices of adjacent crystals, even of different orientation, Fig. 12—100 Diameters THE IRON Fig. 7—100 Diameters Fig. 13—300 Diameters AGE Fig. 8—100 Diameters or alternatively by interatomic force of adjacent atoms of neighboring lattices, or both these reasons. Stead’s brittleness only follows grain growth and occurs in steel of very coarse grain size. The grain growth produced by annealing after straining must have a very important effect upon the spheroidization of carbide, since the ferrite grains grow to the exclu- sion of the fragments of carbide which, to some extent, no doubt, assisted by the pressure of the ferrite, tend to assume the spheroidal shape of any fluid mass sus- pended in another medium. Low carbon steels in which this brittleness occurs are required to withstand cold deformation and still possess mechanical strength, and the phenomenon is conspicuous in these becausé’*in higher carbon steels the carbides act as mechanical ob- structions to grain growth and the relative proportions of the two constituents produce a contrary mass effect. Grain Size and Mechanical Strength There is a further link between Stead’s brittleness and the well-known relation between grain size and. mechanical strength. Returning to the fatigue lines and slip bands produced in Doctor Hanson’s experi- ments with alternating stresses, it is obvious that the stresses are more effective in a coarse grained material because they can work without interruption and with- out change of direction in each plane. It is notable that the lines show a tendency to converge toward the corners of the crystals and this is further evidence in support, since the convergence arises from the resist- ance produced by the different orientation of the ad- jacent crystals. It is now agreed that some crystals, on account of their orientation slip easily and thereby divert the stress on to crystals, of which those unfavorably oriented for resistance slip. Probably the crystals, with principal axis most nearly at right angles to the direction of force, yield first and those with axis paral- lel to that direction yield last, but in the aggregate under stress there is an infinite series of readjust- ments of load. This applies equally well to static tests. The actual yield point of mild steel is a very uncertain quantity owing to the adjustments of the tensile stress following crystal movements. That is, fatigue produced in erystals favorably oriented for slip, throws the load on to other crystals successively, so that the tensile test Fig. 14—300 Diameters pee mere ar 76 THE IRON is really a fatigue test carried out rapidly by a steadily increasing load until all readjustments are overcome and the aggregate breaks. This is quite paralleled by the later fatigue tests in which the stress is rapidly increased, in order to complete a test in a reasonable period of time. It is a matter of common experience that smaller grain size means higher tenacity and greater hardness, and at- tempts have been made to account for this by attribut- ing certain properties to crystal boundaries, such as an intercrystalline amorphous cement. Increased Resistance Is Dynamic It is now suggested that the increased resistance to deformation, in a material with greater boundary area, is dynamic. Since each crystal is of small size, only a very small slip is possible before the stress is diverted to other crystals. Since the number of crystals is large, the number of interruptions is large; also the number of slip bands, which are themselves highly resistant to deformation, and there are much more frequent changes of orientation. The path along which the force moves is very tortuous, much more so than in an aggregate of large crystals. In material of very large crystal size, there is the plasticity of the ferrite crystals, interrupted by the intercrystalline cementite to some extent, but more largely interfered with by variations of orientation by which blocks of crystals move in a mass, being released by the yielding of one crystal, or possibly more. The result is to produce the rough lumpy surface found in coarse grained material after mechanical test. A further point in comparing fine grained and coarse grained material is that the slip bands in the latter are greater in the proportion of the square of the diameter of the crystals. Large mechanical inter- ruptions in the continuity of any material are more effective in producing weakness than many small inter- ruptions. This is well illustrated by the relative AGE July 8, 1926 strengths of cast irons, in which large straight flakes of graphite produce weakness, and small curly flakes and spots correspond with strength of the material. The question of relative grain size is of increasing importance on account of the revolution in manufac- turing methods by which articles, formerly produced by casting and forging, are now made by cold pressing. Motor and cycle parts, formerly built up, are now made in one piece by pressing out of sheet in the cold. For each purpose there is a suitable size of grain corresponding to the requisite ductility for the process of forming and the residual tenacity after forming. Summary It is hereby suggested that divorce of pearlite and spheroidization of cementite, and grain growth, are reciprocal processes; also that annealing after strain- ing is the common cause of these phenomena, by the formation of definite crystals from slip bands, and the growth of these crystals upon the strained portion of the original crystals. Large grain size corresponds with weak material, on account of the less frequent change of direction of the stress applied, and the strength resulting from small grain size is produced by the more numerous adjust- ments of the line of force. Slight straining in coarse grained material is suffi- cient to cause brittleness by reason of the large area of the slip planes. References. (Not inclusive) Journal of the Iron and Steel Institute: I and Il. I. 382. 417. . >. Le Genie Civil —1925. April 4. Stahl und Eisen.—1923. Oct. 4. What Coke Combustibility Means Old and Recent Definitions Criticized—Coke’s “Nature and State”—-Flammability for Combustibility Suggested BY THOMAS T. READ* N his interesting article on the “Combustibility of Coke” that appeared in THE IRON AGE, Feb. 18, R. H. Sweetser not only praises the work done by various investigators of the United States Bureau of Mines, but also gently chides them in the following language: * * * but further results should not be reported in terms that are contrary to those used in the prac- tice of making pig iron. The general idea of this pronouncement is perfectly sound, but to comply with it involves assuming that the terms used in the practice of making pig iron are used in a definite and accurate way that the men of the bureau can comply with. Now that I am no longer a member of the Bureau of Mines, I want to try to demonstrate that the latter assumption is not soundly based, and that the appar- ently reasonable request Mr. Sweetser makes of the bureau’s investigators is difficult, if not even impossible, to comply with. Definition of Combustibility Mr. Sweetser goes on to quote H. A. Brassert as having said in 1906: What principally concerns the blast furnace is the rate of progression of the combustion, which depends not so much on the chemical analysis as on the physical qualities of the coke. It is this rate *Assistant Secretary American Institute of Mining and Metallurgical Engineers, New York. of progression that we term combustibility, which is the speed at which the carbon molecules in the coke combine with oxygen under given conditions. In considering this definition two things are evident. In the first place, Brassert was attaching a new mean- ing to the word. There is nothing in the definitions of combustibility given in the New Oxford, Century or International dictionaries that supports the concept that the word combustibility had ever before any idea of rate attached to it. Until the time of Lavoisier the nature of combus- tion was not understood; Lavoisier demonstrated that it was simply an oxidation process. The oxidation of the carbon in a steel sample by chromic acid is not called combustion; its oxidation in a stream of oxygen is called combustion. The word combustibility means, according to all the dictionaries, that a substance can be oxidized by that variety of oxidation processes called combustion; there is no idea of relativity or rate in it at all. The New Oxford dictionary cites as an example of the correct use of the word Faraday’s statement about the combustibility of the diamond, by which Faraday meant simply that it can be burned. Admitting, however, that it was entirely permissible for Brassert to attach a new meaning to the word com- bustibility, since he proceeded to define his new use of it, we next notice that his definition is inconsistent with itself. He said that cembustibility is the rate of progression of the combustion s * . . which is the speed at which the carbon July 8, 1926 molecules of the coke combine with oxygen under given conditions. These two phrases do not mean the same. The speed at which carbon molecules combine with oxygen is, so far as the chemist knows, infinite. As to rate of progression of combustion let me cite another defini- tion: The velocity of the combination which is pro- duced at a given instant within a homogeneous sys- tem is determined when for this instant the nature and state of the substances forming the system are considered, the temperature to which the system is brought, and the pressure it supports is known— (Thermodynamics and Chemistry, by Dubem and Burgess, page 413). Nature and State of the Coke Evidently the idea which Brassert was endeavoring to make clear was that, in a homogeneous system of which coke is one of the components, the velocity of combustion will vary according to the “nature and state” of the coke, when temperature and pressure in the system are kept invariable, but using the word com- bustibility to express this idea imposes a difficulty of comprehension on the reader that seems to me unneces- sary because, as explained above, combustibility has never been used to signify the nature and state of com- bustible substances, but signifies instead that they are capable of being oxidized in the way that is called com- bustion. Mr. Sweetser does not overcome these difficulties in his suggested definition, which is as follows: The combustibility of a blast furnace coke is the vate of complete gasification of that particular coke in front of the tuyeres of a blast furnace under standard conditions of blast temperature and of blast volume, for he is still trying to make combustibility signify a rate of reaction, which is not only a meaning that it never had, until the blast furnace men sought to so define it but also is, in my judgment, a meaning it can not logically have. The individual piece of eoke that I can hold in my hand has a “nature and state” (which is apparently what Brassert and Sweetser mean by combustibility) that will affect its reaction velocity in combustion independent of temperature and pressure. This “nature and state” is obviously not a rate for it is something permanent and unalterable. All-Metal Wharf Barge A barge with an all metal superstructure has ap- peared on the Mississippi river in Louisiana. It is virtually a floating iron house with iron roof, sides, downspouts, and gutters. More than 20,000 Ib. of ingot iron was used in the superstructure alone, though the sheets were of Nos. 24 and 26 gage material, which is corrugated to stand hard knocks. Wharf Barge Built for the Baton Rouge, La., Transporta- tion Co. by the Midland Barge Co., Midland, Pa. The cabin is 32 ft. 8 in. w 200 ft., on a hull 230 ft. long THE IRON AGE 77 Perhaps an example will make this point clearer. Oatmeal mush can be swallowed without chewing it, dry oatmeal has to be chewed; therefore, oatmeal can be eaten faster in the form of mush than it can be eaten dry. The nature and state of the oatmeal affects the rate of eating it, but its nature and state is not a rate and cannot be defined as a rate. Any attempt to do so not only confuses the reader but also the writer of the definition. Suppose we say “What principally concerns the man eating his breakfast is the rate of progression of the swallowing, which depends not so much on the chemical analysis as on the physical qualities of the oatmeal. It is this rate of progression that we term ‘eatability,’ which is the speed at which the oatmeal slips down the man’s throat under given conditions.” It is here evi- dent that the terms are mixed; the “eatability” is not the rate at which the oatmeal slips down the man’s throat; it is rather the nature and state of the oatmeal that, in turn, affects the rate of swallowing. The rate of swallowing might, under standard conditions, be used as an index of the nature and state, but the rate is not itself a “nature and state” and cannot logically be so defined, because it depends on other things as well as on nature and state. Combustibility Is Flammability My own suggestion is that we abandon the attempt to attach a new and, to me, illogical meaning to the word combustibility and use instead the word flamma- bility, which the dictionaries define as “susceptibility of taking fire readily.” I therefore would amend Mr. Sweetser’s suggested definition to make it read as fol- lows: The relative flammabality of blast furnace coke is indicated by the relative rate of complete gasification of that particular coke in front of the tuyeres of a blast furnace, and can be measured by comparing it with the rate of gasification of a standard coke, both under standard conditions of blast temperature and of blast volume. If Mr. Sweetser will accept this amendment and the blast furnace men will vote in favor of it, we can then proceed to the task of determining the relative flam- mability of different varieties of coke that have a dif- ferent “nature and state.” The cabin itself measures 200 ft. long by 32 ft. 8 in. wide. The dimensions of the barge are 230 ft. long, 40 ft. wide and 12 ft. deep. The wharf barge was built by the Midland Barge Co., Midland, Pa., for the Baton Rouge Transportation Co., Baton Rouge, La. The cabin was built by the Kiefer Sheeting & Painting Co., Pittsburgh, of mate- rial supplied by the American Rolling Mill Co. of a special analysis for rust-resisting qualities. a OP aN q i i ' t t New Hot-Strip Mill in Operation Fourteen Stands Driven by Nine Motors—101 Motors on Run-Out Table and Hot Bed— Producer Gas Used BY ROGERS A. FISKE* OT-ROLLED strip is now being: produced on the H new 14-stand, hot-strip mill ofthe Acme Steel Co., Riverdale, Ill. Slabs varying in size up to 3 in. in thickness, 21 in. in width ang 10 ft. long will be rolled into strips varying in width from 3% in. to 20 in. and in all standard gages. The cold rolling de- partment which this mill serves produces strip in widths from 7/32 in. up to 20 in. and in gages from 0.005 in. up. Slabs are delivered by rail to the slab-storage build- ing, 100 ft. x 240 ft., adjacent to the hot-strip mill building and in such relation to the furnaces that the Air for the Slab-Heating Furnaces Is Preheated to About 1300 Deg. Fahr. draft fans are used Whiting 10-ton overhead electric crane can deliver slabs to the electrically-driven pushers at the charging end of the furnaces. The pushers are motor driven through gears, and the operator, with remote controls before him, stands near the charging end and between the two furnaces. Surrounding these furnaces is an un- usually complete and well designed system of plat- forms and stairways, with flooring of subway grating made by the Irving Iron Works Co., Long Island City, N. Y. The furnaces are side by side, and slabs from either furnace may be discharged to a single line of feed rolls, on which they are conveyed to the slab shear. Seven stands in the roughing mill, three in the inter- mediate mill and four in the finishing mill constitute the 14 stands of the mill. A slab, after passing the shear, first goes through the horizontal edger, desig- nated as stand No.1. It then passes through two 20-in. roughing stands, through stand No. 4, a second hori- zontal edger, and then through No. 5 stand, a 20-in. roughing mill. Stand No. 6 is a vertical edger and the last pass of the roughing mill is a 20-in. mill designated as stand No. 7. *Western editor THe IRON AGp, Chicago. consists of stand No. 8, a 9, a 16-in. mill, and stand No. 10, also a 16-in. mill. The finishing mill consists of stands Nos. 11, 12, 13 and 14, which are all 16-in. Space has been provided for two additional stands. The pinions and roll housings were all furnished by E. W. Bliss Co., Brooklyn, N. Y. The intermediate mill vertical edger; stand No. Vertical Edger Is Driven by a Separate Motor Stands Nos. 1, 2, 3, 4, 5 and 7, that is, the roughing train, are all driven by means of a 1500-hp., 2300-volt, 3-phase, 60-cycle induction motor geared to a long line i. TS a Lee} Ri ron Neither forced nor induced shaft which extends parallel to the mill. No. 6 and No. 8, vertical edgers, are separately driven by means of 600-volt, 100-hp., variable-speed, d.c. motors. No. 9 stand is driven through gears by a 1500-hp., 600-volt. d.c. motor. Stands Nos. 10 to 14 are driven by indi- vidual 1800-hp., 600-volt, d.c. motors; No. 10 is driven through gears, and Nos. 11 to 14 are direct-connected to the motors. All reduction gears used in connection with the drive of this mill were furnished by the Farrel Foundry & Machine Co., Buffalo. Tables and the hot beds used in conjunction with this mill were furnished by the Treadwell Engineering Co., Easton, Pa. The runout rollers extending from stand 14 to the end of the hot bed are 97 in number, each separately driven by a %-hp. direct-connected Westinghouse motor, 220-volts, 3-phase, 25-cycle, and 340 r.p.m. Ten of these rollers are mounted between No. 14 stand and the hot bed, and the remaining 87 are required to cover the full length of the hotbed. That these rollers may be synchronized with the speed of the No. 14 stand, a separate generator (furnishing power to these rolls) is belted directly to the drive of that stand. The normal speed of this generator would provide electric current at 25 cycles.. Any variation in July 8, 1926 THE IRON AGE (At Top) The Main Opera- tor’s Pulpit Is Located in the Wall Which Separates the Mill Room from the Motor Room (At Right) Stands Nos. 1, 2, 3, 4, 5-and 7 in the Roughing Train Are Gear Driven by Means of a 1500-hp. Motor (Below) An Unusual Hot- Bed Layout. The 97 run-out rollers are each separately driven by a direct-connected motor 80 THE IRON the speed of the mill will be followed immediately by a corresponding change in the speed of the rollers. The hot bed, approximately 50 ft. wide by 250 ft. long, is equipped with transfer bars which move the finished product to either side, to the electrically oper- ated shuffle bars which place the product within reach of the transfer rollers. The drives for these rollers are grouped, so that only two motors are required on each side of the hot bed. At the end of each run of transfer rollers is a belt-driven Treadwell Engineering Co. gage shear. Immediately beyond each gage shear is a piler table, and finally an E. W. Bliss Co. coiler. Located at the side of the building between the in- termediate and finishing mills is a motor-driven, jaw- type scrap shear. The drive and rear end of the shear extend into a lean-to, but the cutting jaws project into the main bay, so that the overhead electric traveling cranes can handle material to and from the shear. Furnaces Are of Recuperative Type Two slab-heating furnaces, of the recuperative type, were designed and built by the Chapman Stein Furnace Co., Mount Vernon, Ohio. Each furnace is designed for a capacity of 15 tons per hour and is sufficiently wide to take slabs 11 ft. long. The recuperator for preheating the air is below the furnace and is so de- signed that air enters at the bottom beneath the charg- ing end of the furnace, passes upward through the re- cuperator and then forward to the firing end, where it rises through the brick-lined, sheet-metal ducts at each side and enters an air box located above the gas box. Producer gas enters at the discharge end of the fur- nace. The split-flame method of firing is used, which causes the products of combustion to heat the slabs both above and below and in this manner pass to the charging end of the furnace and then downward to the recuperator. After the waste gas makes three hori- zontal passes, the length of the recuperator, it traverses an underground flue to an 80-ft. steel stack lined to the top with fire brick. Air ports in the furnace are located directly above the gas ports and no mechanical power is required, either for the induction of air into the furnace or for the removal of the waste products of combustion. The gas pressure at the furnace is 0.20 in. of water and Ce ee ma’ D i At the End of Each Line of Transfer Rollers Are a AGE July 8, 1926 the pressure of the air at the furnace ports, which is under the natural head created by the difference in tem- perature between the heated air and that of the atmos- phere, is 0.15 in. of water. The air used for combus- tion is heated in the recuperator to within 400 or 450 deg. Fahr. of the temperature of the waste gas in the downtake of the furnace. This latter temperature will normally be about 1700 to 1800 deg. Fahr., indicating that the temperature of the air for combustion will be some 1300 deg. Fahr. Each furnace has four skid pipes made of 2% in. double-extra-heavy seamless tubing. On top of each pipe is welded a %-in. bead. It has been found that this bead on the top of the skid pipe is helpful in elim- inating cold spots on the slabs, which are present when the slabs rest directly on the pipe. The skids run the length of the furnace and a slag or cinder pit is pro- vided beneath the pipes at the discharge end. The bot- tom of this pit is covered with coke breeze upon which the cinder and slag drop. Doors on each side of the furnace permit easy removal of the cinder. This fea- ture eliminates Sunday labor for cutting down the hearth, which is necessary when a brick-soaking hearth is employed instead of skid pipes. Cooling water for the skid pipe is pumped from a nearby stream to an overhead stand pipe, from which it flows by gravity to the furnaces. After passing through the skid pipes the water drains to three scale pits, located beneath the hot-strip mill. There it acts as a means of conveying scale from the mills to scale pits located outside the main building. The scale pit opposite the furnace run-out table is approximately 43 ft. long by 10 ft. wide; the two others are each about 23 ft. long by 10 ft. wide. These are open concrete pits, cleaned periodically by means of a bucket suspended from the boom of a locomotive crane. One of the smaller scale pits takes care of the accumulation at stands Nos. 1, 2, 3, 4 and 5; the other small pit takes care of stands Nos. 6, 7, 8, 9 and 10. Producer gas is made in a separate structure to the west of the hot-strip mill building. Two No. 10 Well- man-Seaver-Morgan Co. full-automatic mechanical gas producers, each having a gasifying capacity of 4000 lb. of coal per hour, are used. The coal burned during the first few weeks of operation of this plant was from the East Kentucky fields. Coal, delivered to the plant by mo = —- : | Gage Shear, a Piler Table and a Coiler July 8, 1926 in standard railroad cars, is unloaded into a 12-ft. x 12-ft. steel track hopper, the mouth of which is raised but a few inches above the yard level. The coal passes from the hopper to a 30-in. apron conveyor which ele- vates it to the hopper of a double-roll crusher, belt- driven from an electric motor. Crushed coal falls down a chute to the boot of a bucket-type elevator which unloads into two unlined steel hoppers located over the gas producers. The entire coal-conveying system and the crusher were furnished by the Link-Belt Co., 300 West Pershing Road, Chicago. Gas leaves the top of each producer and passes through a steel soot collector. Gas gathered from these two collectors passes through « third collector before entering the main which leads to the heating furnaces. All three collectors are located between the gas-pro- ducer building and the hot-strip mill building, and the gas main leaves the last collector at such a height that it pitches downward at about 25 deg. to enter the hot- strip mill building. Inside the building the main runs horizontally, with its center about 7 ft. above the floor. It is constructed with three dust legs ahead of the point where the first furnace connection is made. The main flue, 6 ft. in diameter, is lined on the inside with 2% in. of insulating material and 4% in of fire brick. All Electric Power Is Purchased Electric current for this plant, purchased from the Commonwealth Edison Co., Chicago, enters at 12,000 volts, 3-phase and 60-cycles. It is stepped down to 2300 volts through a set of single-phase transformers; another set of transformers steps down such current as is required at 220 volts. A transformer on the light- ing circuit provides current at 110 volts. The main motor room is built adjacent to the main mill building and is opposite to the intermediate and finishing mills. In it are located the central control switchboard, two motor-generator sets and an exciter set. Space is pro- vided for two additional motor-generator sets. Each such set consists of a 2850-hp., 2200-volt, 3-phase, 60- eycle motor mounted on a common shaft with two 1000-kw., 600-volt, d.c. generators. The exciter unit consists of a 940-hp., 2200-volt, 3- phase, 60-cycle motor mounted on a common shaft with two 300-kw., 250-volt, d.c. generators and a 50-kw., 250-volt, d.c. exciter. All the motor and control equip- ment used throughout this mill was furnished by the Westinghouse Electric & Mfg. Co. The transformers are located in a separate room, adjacent to the motor room and the hot-strip mill building. They are mounted on platforms placed sufficiently high above the floor so that a transfer table, operating on rails, can move the transformers from that room to the mill building, THE IRON AGE No. 6 Stand, Which Is a Vertical Edger, Is Separately Driven 81 where they can be handled by the overhead electric crane. The main control pulpit is mounted above the floor level and in the wall which separates the hot-strip mill building from the motor room. The operator in this control room has at his command all of the main switches and also the controls of all of the mill stands except the edgers, which are controlled individually from the operating floor. A separate motor-control stand handles the hot bed and another, opposite the in- termediate and finishing stands, provides for the manip- ulation of the looping aprons, which are operated by means of compressed air. The motors which drive the mill are housed in brick inclosures covered with removable roofs, so that the motors may be readily accessible to the overhead elec- tric cranes. Two motor-driven, Buffalo Forge Co. blow- ers, each rated at 50,000 cu. ft. per min., are mounted in a separate room at the end of the motor room, to pro- vide air for the mill motors. The air is passed through filters made by the Reed Air Filter Co., 215 Central Avenue, Louisville. Building Is 70 x 2000 Ft. The new hot-strip mill is located in an extension to a mill building which houses the stock room, the pickling vats, and the annealing ovens of the cold- rolling mill. The building as it now stands is over 2000 ft. long. Its width is 70 ft., and the crane run- way throughout its length is standard, so that the four cranes can be used in any part of the building. The new cranes, installed primarily for the hot-strip mills, are a 25-ton crane with a 5-ton auxiliary hook and a 10-ton crane, both made by the Whiting Corporation. The old cranes which operate on this runway are of 35 and 10-ton capacity. The building is of the steel-frame, mill type, the roof and siding being of corrugated metal. The mon- itor is fitted throughout its length with ventilated steel sash. Fabrication and erection of the building were carried out by McClintic-Marshall Co., Pittsburgh. With the installation of this mill it was found nec- essary to add to the capacity of the boiler house. Ac- cordingly two 500-hp. Union Iron Works (Erie, Pa.) boilers are being erected. These will operate at 160 lb. pressure, without superheat. Chain grate stokers were furnished by the Illinois Stoker Co., Alton, IIL, and the forced draft fans by the Buffalo Forge Co. The new reinforced concrete stack which will serve these boilers is 10 ft. inside diameter by 237 ft. high. It was constructed by J. V. Boland Construction Co., St. Louis. The water-treating plant for the boilers was by the Graver Corporation, East Chicago, Ind. What British Foundries are Doing Developments in Gray Iron Covered at the Annual Meeting of Institute—New Foundry Equipment Exhibited «(Special Correspondence) LONBON, ENGLAND, June 25.—The International Foundry Trades Exhibition, the fourth of its kind to be held in Great Britain, was held in London last week in order to coincide with the annual convention of the Institute of British Foundrymen. Cooperating with the organ- izers are the National Physical: Laboratory, the research department of Woolwich Arsenal, the universities of Birmingham, Sheffield and Glasgow, and other research bodies, who between them have arranged an important group of scientific research exhibits. Some of the most important and interesting papers at the sessions of the I. B. F. as well as a brief account of leading features of the exhibition are found in the following account. Papers on Cast Iron HE annual conference of the Institute of British Foundrymen makes no pretensions to being an inter- national one, yet it was attended by a large number of overseas visitors, and was characterized by the ex- cellence of the foreign exchange papers. Quantity Output of Quality The most important American Foundrymen’s “Quality in Quantities,” paper presented was the Association paper entitled by Arnold Lenz of the Saginaw Products Co., Saginaw, Mich. This paper epened up the question whether it is possible to produce, under mass production methods, an article comparable with that made by hand-molding methods. It showed in the clearest possible way that, while quantity production methods demand less skill from the craftsman, they enlist the closer attention of the management, and that this intense application of ingenuity by the management results in the production of really high-grade castings. A production foundry, employing about 2500 men, may not employ over 10 full-fledged molders and coremakers. The burden of supplying the necessary knowledge of the details in- volved in the manufacturing of a great tonnage of in: tricate castings falls, therefore, entirely on the man. agement. For this reason, to operate successfully a production foundry with the most efficient equipment to maintain it, to design the necessary special appli- ances and to organize its force in such a way that the product will flow through the plant in a continuous un- interrupted manner, is best accomplished if the execu- tives are advanced from the ranks by merited promo- tion. Uniformity of mold and core shape, control of the physical and chemical properties of the metal, sand and other raw materials assume greatly enhanced im- portance under quantity production methods. Improvements in Cast Iron High-tensile cast iron was dealt with in a paper by Louis Piedboeuf of the Belgian Foundrymen’s Associa- tion, who emphasized the advantage of low-carbon con- tents. The lower the carbon content, the wider the zone of pearlitic structure. There is thus greater cer- tainty of getting the pearlitic structure without the risk of encroaching on adjacent zones. By keeping at an equal distance from the cementite and ferrite zones, there is a greater chance of getting the pearlitic struc- ture without heating the mold. In the higher carbon machinery cast irons, a considerable increase in the graphite lamellz will always be found toward the cen- ter even where the diameters are smaller. With low- carbon and high-silicon pearlitic cast irons, it is pos- sible to obtain an identical texture in the thin and the thick parts of the same casting. Diminution in the size of the graphite lamellz, which is also important, has been effected by treating the metal in an oil or electric furnace, and, according to Piwowarski’s researches, it and Foundry Sand is principally by superheating the liquid iron that the finely distributed graphite is formed. But it would be no use trying to reduce gaps caused by faulty distribu- tion of the graphite lamellz, if other discontinuities were allowed to persist in the shape of blow holes, seg- regations, or internal stresses. In a specimen cast iron a tensile strength of 15.7 to 17.6 tons per sq. in. was ob- tained (in spite of a phosphorus content of 0.8 per cent) by a purifying treatment carried out in the fire- hearth by alkaline substances. Foundry Sands R. Lemoine, on behalf of the French Foundrymen’s Associates, dealt with the question of molding sands, and he showed quite clearly that some types of wasters can be anticipated and prevented by the common sense application of sand control. The latter amounts to adapting the composition of the mixtures and their preparation. The determination of the equilibrium fac- tors should be carried out in many foundries, even in those which insist that they are satisfied with their molding sands, but which, periodically and because wasters increase, reject a portion of their old sands to be distributed in new material. General control of sands amounts to assuring constancy of permeability and cohesion, by controlling the composition of the mix- ture, and the author shows that apparatus for measur- ing these in the cold state, when employed according to certain methods, may be of great service in the foundry. Cast Iron for Electrical Machines Although cast steel has almost entirely replaced cast iron for electrical machinery, J. H. Partridge, of Birmingham, as the result of a highly interesting re- search carried out under the direction of Prof. Thomas Turner, definitely disproves the old idea that cast iron does not have any useful magnetic properties, and he predicts for this material a promising future in the electrical industry. He finds that the highest magnetic induction and permeability are obtained with cast iron which has been annealed. In the extreme case the magnetic induction was increased 70 per cent and the maximum permeability was increased ten-fold on an- nealing. When high permeability is required, the graphite should be in the form of temper carbon. In the cast state, silicon decreases the magnetic induction, but its presence may be advantageous in alloys which have to work at low flux densities. Manganese, nickel and chromium are prejudicial to high magnetic induc- tion. In the annealed condition aluminum, in amounts up to 1 per cent, decreases the magnetic induction, but above that and up to 3 per cent it causes a huge in- crease in the induction and permeability. An easily machinable non-magnetic cast iron could be made by having nickel and manganese present in such propor- 82 July 8, 1926 tions that the combined effect of these two elements on the carbon is negligible. Sufficient silicon would then be added to precipitate just sufficient graphite to give the required strength, machining properties, surface, etc. The author shows that it is possible to produce cast iron with a hysteresis loss equal to that of soft iron, certainly less than that of wrought iron or mild steel. This class of cast iron should enable cast iron frames Some British Molding HE commercial exhibits were in every way worthy of the non-commercial exhibits and cover the whole range of foundry work. Various types of molding ma- chines formed the largest individual exhibit, but there were, in addition, representative examples of riddling machines, sand mixers, conveyors and pattern-making machinery. Finished castings and raw materials were also well represented, together with cupolas, brass- furnaces and miscellaneous equipment. A Jar Ram Molding Machine Foremost among the exhibits of recent design was the jar ram molding machine shown by the Britannia Foundry Co., Coventry, in which the jolting, squeezing and lifting operations are all performed by compressed air. The air enters thro