The Iron Age 1909-06-03: Vol 83 Iss 22

% b 5 THE IRON AGE Published every Thursday Morning by David Williams Co. 14-16 Park Place, New York. Vol. 83: No, 22. New York, Thursday, June 3, 1909. foe ee Reading Matter Contents........ page 1820 Alphabetical Index to Advertisers ‘‘ 298 Classified List of Advertisers " 287 Advertising and Subscription Rates ‘‘ 1838 REED F. BLAIR & C0. FRICK BUILDING, PITTSBURG, PA. STANDARD CONNELLSVILLE C O K E The Steel Lined They sell FOUNDRY FURNACE CRUSHED ihemselves A NEW LIGHT on the SHOT SHELL TRADE The Steel Lining in all U MC smokeless powder shells throws a new light on every department of the shot shell trade. To the jobber and retailer it means the strongest selling point ever presented—no other shells are steel lined. To the consumer, it means a stronger shell—added quality without an added price. Read the writing on the wall. Meet the call for our Arrow and BRISTOL’S PATENT STEEL ‘BELT “LACING : Nitro Club Steel Lined Shells. THE UNION METALLIC CARTRIDGE CO. Bridgeport, Conn. AGENCY - 315 BROADWAY - NEW YORK CITY The original and only Genuine ‘*‘STILLSON WRENCH ”’ eS So is manufactured by WALWORTH MFG. CO., Boston, U. S.A. And bears their registered Trade-Mark The Bristel Company, Waterbury, Conn. | WATER TUBE The Babcock & Wilcox Co., BOILERS See page 63 + "tee UNEQUALLED ‘gp x: s ? The great majority of \) *\Horseshoers and Horse Owners | Tinseucenss Sa Agree upon this point. \ WEA Cleveland City 58 and Iron Co., Cleveland, 0. Bye iQhY Th d_City F 20 Tin 99 e Safest Nails TURNBU = a re apewell Nails The Most Lasting TT iat Maspeth, New York, N. Y. MADE BY F O R G | N G S The Capewell Horse Nail Co. Hartford, Con a & A PILLING & CRANESS* Erato" ee, Poe cote JenKins Bros. Valves have the favor of engineers because they are the easiest to keep tight. Made of new steam metal of best quality. Interchangeable parts. Con- tain genuine Jenkins Discs—either Hard, for steam and hot water use; or Soft, for cold water, air or gas. May we send yuu Catalog ? 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CO., Seymour, shies AND TUBING Ta sn ecienedesietainesiceihdeiaiatiaiaiesbiemematarialaiininadidaadeaaiaceinietie ~—— HENDRICKS BROTHERS _|COPPER | wire — Manufacturers of Sheet, Rod, Wire and Tubing Sheetand Bar Copper, Copper FireBox Plates and Staybolts, Wire and Braziers Rivets PHOSPHOR -BRONZE Imperters nd‘Dealers in GERMAN SILVER t » Block, Ti Spelter, Lend, Andmeny, Bismmth, Michel, etc. TWAETAL Co 49 CLIFF STREET - . NEW YORK many Se RIVERSIDE N J. THE IRON AGE New York, Thursday, June 3, 1909. A Study of Electric Furnaces.” As Applied to the Manufacture of Iron and Steel. BY CHARLES ALBERT KELLER.} The application of electric furnaces of the electrode type to the production of metals which must be won, melted or transformed out of contact with carbon, and more particularly the solution of the problem of making steel, created the necessity of so making the conducting hearths or bottoms of such furnaces as not to carburize the liquid metal contained therein. The conducting hearths of electric furnaces currently used for electrometallurgical products (calcium carbide, ferrosilicon, ordinary ferrochromium, &¢c.) have from the very first been either made of a rammed mixture of car- bon and a binder, or built up with pieces of electrodes; the carbon lining thus formed being connected in various ways with one of the poles of a source of energy, the ter of great secrecy. When the problem of the electric furnace manufacture of steel became a ljve one, it cre- ated the necessity for the noncarburizing conducting hearth. On the other hand, it has been known since the prac- tical use of the electric furnace first began that when dealing with products giving rise to a slag (treatment of chrome ores, for example) the regulation of the are voltage requires that the end of the electrode be kept in this slag or above it, since contact with the metal would at once cause a practically complete short circuit. It becomes evident then that, given a noncarburizing hearth already in use, the electric furnaces in the older electrometallurgical works were, in principle, all ready Fig. 1.—The Keller Electric Furnace other pole being connected to one or more electrodes placed vertically in the furnace. Although it is only within recent years that the types of furnaces using conducting hearths or bottoms have been worked on the industrial scale with materials other than carbon, it should, however, be borne in mind that the making of a conducting hearth without carbon had been done long before and used at various periods. If no industrial electric furnaces followed this realization it was principally because the construction of a prac- tical metallic conducting hearth, or of a hearth contain- ing a metallic pole, presented greater difficulties than the simple carbon hearth. The need, too, for a noncarburiz- ing hearth had not-then made itself felt in the electro- metallurgical art, save for some unimportant lines of manufacture, where the methods used were made a mat- *From a paper read at the Niagara Falls meeting of the American Electrochemical Society. + Managing director of the Société des Establissements Keller Leleux, Livet Works. Isere, France. at Unieux.—Removing the Roof. for the manufacture of steel, since the upper electrode, because of the requirement of its position electrically when working, cannot of itself effect carburization of the bath in the furnace. Then, to better fit such furnaces for metallurgical operations, it should only be necessary to supply them with details already known and applied to certain electric steel furnaces (charging doors, rockers, rollers for tilting movements, airtight roofs, &c.) which would not introduce any difficulties or hinder the ra- tional study of an electric furnace based upon the use of a conducting hearth to carry the current. Nonearburizing Conducting Hearths, At the present time noncarburizing conducting hearths may be divided as follows: 1. Simple conducting hearth: a, Having the entire furnace bottom of metallic ma- terial. b. Having one or more metallic poles embedded in a nonconducting masonry. 1754 THE c. Having the entire bottom of a conducting rammed material. 9° 2. Compound conducting hearth: I shall here more especially describe a system worked out by myself, consisting of a type of mixed or compound connecting hearth. Nevertheless, to precisely define why this system is thus classified and what differentiates it from the other types, I shall briefiy describe the first category and its various subdivisions mentioned. 1. a. Entirely Metallic Hearths.—Several types of fur- naces have been designed whose hearth is made of soft steel, cooled by water circulation, but these have not had any important commercial application; they are simply mentioned as a type. The high temperature of the liquid metal does not permit main- taining a metallic bottom, even when cooled, except with an exces- sive loss of heat and constant dan- ger FURNACES WITH SIMPLE CONDUCTING HEARTH: b. Simple Conducting Hearth, Consisting of One or More Metallic Poles Embedded in Nonconducting Masonry.—In such furnaces one or more metallic poles are embedded in masonry of the hearth, the current passing through the metal pieces; these conductors are connected at their outer extremities with one pole of the source of energy. This type of furnace is distinguished by the fact that the current is con- fined almost entirely to the metallic pole or poles if it is divided into several parts by a refractory non- conducting masonry, the masonry surrounding them closely as pro- tection against infiltration by the liquid ‘metal. The first furnace of this type was installed by Siemens, who contrived a furnace composed of a movable vertical electrode con- nected to one pole of the source of energy, the other pole being con- nected to an iron bar passed through an opening in the bottom of the furnace .chamber. This chamber was surrotnded by a heat insulator, and later Siemens adopt- ed a method of water cooling the metallic pole to prevent its destruc- tion. Regulation of voltage was ef- fected by an automatic solenoid reg- ulator. « A very distinct type of furnace was invented by Borchers. An iron casing having a bottom of refrac- tory brick is lined with a suitable material. In the bottom lining is placed a block of steel, into which screws a copper tube, used for cir- culation of the cooling water for the metallic steel poles. The steel block thus cooled is connected at its lower extremity to one of the poles of the source of energy, the other pole being con- nected to a vertical electrode, movable for the purposes of voltage regulation. During the working of the fur- nace the metal which collects at the bottom is tapped from time to time, while the gases escape through the openings in the cover. In spite of the surpassing electro-metallurgical feats of Siemens, who, at the Electrical Congress at London, in 1880, publicly showed with his metallic pole furnace a cast of about 45 Ib. of steel, this type of furnace did rot have an immediate industria] future. , The manufacture of steel in such a furnace was not then a live question, and it had to wait until 1905, when the furnace with metallic poles was again revived by Girod, who installed several of them. IRON AGE June 3, 1909 c. Conducting Hearth Obtained by Use of a Rammed Conducting Lining.—Under this system the hearth does not require a metallic conductor; it is formed of a re- fractory mixture rendered conducting by the introduction of carbon, or carboniferous material (tar, pitch) into the refractory material (magnesia, silica, &c.) chosen for the mixture. The carbon content of the material is pro- gressively raised at different levels in the depth of the hearth, so as to utilize at the beginning of a run the variations in electrical conductivity of the rammed mix- ture, according to the content of carbon material. The upper layer of the lining mixture which comes into con- tact with the steel.is formed of a mixture quite low in carbon, so as not to influence the carbon content of the steel. According to the inventors, the crucible having once been heated becomes permanently conducting, no rs = | la Sa el aa baal ht We ee ' 1 - « “ ee oe ay vj _~. — ra Fig. 2.—The Keller Electric Furnace at Unieux.—End View. matter what the variations of temperature of the fur- nace, consequently restarting from the cold state becomes practically possible. The Firminy Steel Works, where this furnace was installed, has constructed up to the present time only one furnace of small capacity. 2. COMPOUND CONDUCTING HEARTH: I invented and put to industrial use two years ago an electric furnace* of which the conducting hearth is composed of reinforced pisé (pisé armé) made as follows: Iron bars 1 to 1% in. diameter, regularly spaced about 1 to 1% in. apart, are placed vertically and made firm to a metallic plate at the bottom, so as to form a group completely filling the furnace bottom, upon which will our French patent Ch, A. Keller, No. 393,740, November 4, June 3, 1909 rest the liquid metal. A pis6 consisting of a basic mate- rial conductor of the second class (magnesia preferred), agglomerated in the ordinary manner, is strongly rammed while hot between each group of four adjacent~ bars, which thus form by reason of their mechanical strength a sort of mold, permitting considerable compression of the mixture introduced. The pisé thus formed must be driven home by means of a suitable rammer. There is thus obtained an extremely compact mass or block of compound nature, iron and refractory material, of which the metallic sections are good conductors when cold; when heated the pisé also rapidly becomes a con- ductor with the high temperature. The whole is sur- rounded by a metallic casing serving as an envelope which may be cooled by a current of water. The lower plate fastened to these iron bars is connected to one of the poles of the source of energy. The conducting hearth thus preduced makes the starting up of the furnace very easy, because it is uni- formly conductive throughout its entire transverse sec- tion, by reason of the iron bars placed near together and terminating at the surface of the hearth. The small dis- tance between the bars and the conductivity of the pisé practically places them electrically in parallel for their whole length when the furnace is in full operation. The distribution of the electric current is thus practically equalized throughout the whole section of the hearth. The lines of flow of current which are produced in furnaces having isolated metallic poles are absolutely re- moved by the above arrangement, because the electric current from the upper electrode passes through the metal uniformly and also in the same manner throughout the section of the hearth. The electrical resistance of a conducting hearth con- structed as described is almost negligible, because the area of the furnace bottom allows of the use of a large number of bars, representing a total conductivity so high that without considering the conductivity of the pisé the loss is negligible. Furthermore, the use of metallic con- ductors of small section produces a more rational flow of alternating electric current than the use of large sections. - This conducting hearth block constitutes the original portion of the furnace, of which the working chamber is formed as ordinarily by a metallic structure lined with basic refractories strongly secured and braced. The chamber is enlarged above the hearth for better support of the hearth block. The pisé is easily repaired through the charging doors, after tapping, when necessary. The body of the furnace is cooled on its entire periph- ery at the upper level of the hearth, to insure protection at the junction of the lining of the working chamber with the hearth, The furnace is closed by a roof, through which the electrode passes. The regulation of the electrode is ac- complished either by hand or automatically; the latter is more simple and preferable. To avoid shutdowns when replacing an electrode the latter is placed at the end of a swinging arm, so that it may be removed out of the way and replaced by another electrode all ready at the end of a similar swinging arm; the changing of an electrode is thus accomplished in 2 to 3 min. The electric furnace, as I have thus described it, allows of the use of one or more vertical electrodes, which are arranged either of the same polarity and in parallel or upon each phase of a polyphase circuit, A three-phase furnace will require, it is understood, three electrodes, and if the star connection is used the neutral point would be connected to the conducting hearth. I have found that the hearth of a furnace of 3300 Ib. capacity, especially dismantled for inspection and study, after several months’ service, was in absolutely as good condition as on the first day, the pisé having acquired an extraordinary hardness, comparable to rock, so that a drill was blunted. I am satisfied that such a construction supplies as simply and surely as possible a noncarburizing conduct- ing hearth, permitting, in an exceedingly simple and cer- tain manner, metallurgical operations, eradicating all the ordinary annoyance of hearths, their repair and recon- THE IRON AGE 1755 struction, while at the same time providing an electrical conducting hearth free from appreciable industrial losses. The Electric Furnace with the Conducting Hearth and the Furnace with Electrodes, The manufacture of steel may be carried out to con- siderable advantage in a noncarburizing conducting hearth, of course, on the condition that the design of hearth adopted is not a source of annoyance on account of frequent repairs. Here a question arises as to the advantage which may be obtained with a furnace having a conducting hearth compared with a furnace having vertical elec- trodes in series, these serving for entrance and exit of the current, a type of furnace which already has an im- portant place in the history of the electrical manufac- ture of steel. After having made much use of electric furnaces with electrodes in series I am convinced that the question which I propose above, and which I have heard proposed several times, is not without interest, and it was this which led me to carry out a parallel study of the two types of electric steel furnace. I under- took a research as to whether the complete electrifica- tion of the mass of molten steel presented a real metal- lurgical advantage as compared with the process using superficial electric heating characterizing the furnace with electrodes in series. I believe that an electric furnace with a conducting hearth presents metallurgical advantages over the fur- nace with electrodes in series so far as concerns a fur- nace of low or medium capacity. In fact, the method of heating which characterizes the furnace with a con- ducting hearth, on account of the current being forced to pass through the whole mass, is advantageous as re- gards the production of a metal having a thoroughly homogeneous quality. Moreover, the furnace with a con- ducting hearth is of very simple mechanical construc- tion; its starting and operation are more simple when it is used for the treatment of a cold charge; and again it must be noted that the preservation of the roof is easier with a furnace having a conducting hearth. Yet a formal coliclusion is a delicate matter, and I understand the hesitation of the metallurgist who has to compare the two types of furnaces when he desires to produce steels of an altogether high grade, because on @ priori grounds and with considerable reason he would consider that the electrification of the steel] may be advantageous as regards its homogeneity, and thus - give the preference to the furnace with the conducting hearth, while at the same time he may be tempted by the greater ease of construction which characterizes a furnace having electrodes in series. It is a fact that this furnace does away with all electrical fittings in its lower part, since the entrance and exit of the current are confined to the upper part, and this is an importance simplification. Moreover, it should be remarked that in the latter type of furnace with an equal rate of genera- tion of energy the current density is only one-half that in the fufhace with the conducting hearth, which effects economy in the matter of electric conductors. The fur- nace with the conducting hearth necessitates a pretty large inductive loop, in which we have the body of the furnace itself, while this is outside the magnetic field in the case of furnaces having electrodes in series. The power factor may be lowered considerably in the first type of furnace if special precautions are not taken. It is necessary to resort to the construction of non-mag- netic gaps in the furnace body and its fittings; and in* addition great care must be taken to avoid the use of fittings made of a metal of high magnetic permeability, such as wrought iron, cast iron or steel, inside the in- ductive loop. Although these precautions do not involve an impossibility, they nevertheless present an appreci- able difficulty in construction which is far from being so marked in the case of the furnace having electrodes in series, where the in-going and out-going path of the cur- rent is altogether outside the furnace body and its fit- tings. In my opinion, with a frequency of 20 periods a 1000-kw. furnace may have a power factor of 0.9. Such a furnace used in the refining and finishing of molten ' i. : 1756 THE IRON AGE steel will have a capacity of 10 to 12 tons. A furnace of greater capacity could be obtained with the combination of several similar elements, that is by putting several electrodes in parallel, and there is no reason why the power factor should be reduced, Therefore, as regards the type of furnace having a conducting hearth, the whole practical question is as to the design of the hearth. If the construction of this hearth is such that its electrical conductivity is assured, and that its maintenance is perfectly feasible, the prob- lem is solved, and this type of furnace may be adapted equally well for a unit of large capacity as for one of small capacity. It remains, then, to determine in a practical way if the method in which the electric current flows in the steel bath forms a real metallurgical advantage. If this is so the furnace with the conducting hearth has a determining factor of preference over the furnace with electrodes in series. Furnace with Electrodes in Series and Improvements Thereon, After a series of sundry industrial tests I patented in France* and in certain other countries a furnace with PLE ES ESS June 3, 1909 Following these tests, which, of course, will be found very incomplete, now that the question has been actively elaborated in many places, I installed at the works of the Société des Establissements Keller-Leleux, at Livet (Isere, France), a two-electrode furnace tapping 5500 Ib. This furnace was experimented with from 15902 to 1905, with the collaboration, from the metallurgical side, of J. Holtzer & Co. of the Unieux Steel Works, Loire, France. In 1905, following the results obtained at Livet, the installation of an electric furnace of 8 to 10 tons capacity at the Unieux Works was decided upon. This was the first electric furnace adopted in France by a steel works. It was and probably still is the most important electric furnace put into operation. The Keller Electric Furnace, Installed at the ‘{teel Works of J, Holtzer, Unieux, France, In the course of the electro-metallurgical campaign started at Livet I was able to satisfy myself that the electric furnace already had a place in the present day . steel works, even if electric energy could not be obtained from water hours, but upon condition that the use Fig. 3.—The Keller Electric Furnace at Unieux.—Side View. vertical electrodes for entry and exit of the current, combined with a view to obtaining products by the “ tap- ping” method, the characteristic of this furnace being the separate regulation of the two hearths created re- spectively at each electrode; that is to say, the realiza- tion in a furnace, designed to tap the products obtained, of working two separate chambers above a conductive mass completing the circuit between the two electrodes. _ Until 1902 I experimented with this furnace at the Kerrousse Works (Morbihan, France) for various appli- cations, and notably for the manufacture of steel, when starting up with cold charges. I had available at Ker- rousse a furnace tapping 1750 lb., permitting me to make steel ingots, which were tested at various places. The much mourned Ch. Bertolus of St. Etienne visited this installation and made it the object of a communica- tion to the Congres de la Houville Blanche in 1902. Mr. Bertolus had previously made tests of the steel ihgots from Kerrousse at several steel works in the neighborhood of St. Etienne, and published the results of the tests made at one of these works. * French patent Ch. A. Keller, No, 300,630, December 15, vv. of the electric furnace should be confined to reheating, mixing, deoxidation and purification of steel. So as early as 1902 I patented * a method of dividing the manufacture of steel into two phases, confining to special electric furnace the operations above indicated. Liquid steel as obtained by. the ordinary methods not being available, as the Livet Works did not have metal- lurgical furnaces for making steel, I instailed two elec- tric furnaces, one suspended above the other, the upper furnace serving for the oxidizing fusion of iron and steel scrap, the second taking the liquid steel so melted. I was thus able to determine the quantities of energy useful for each operation, and the scheme adopted for the Unieux installation arose from this series of experi- ments. Holtzer & Co. were the first metallurgists who de- cided to commence the construction of a complete electro- metallurgical installation, intended for finishing in an electric furnace steel previously melted and refined. The necessary energy for this installation is furnished by a steam engine. The electric furnace of the J. Holtzer Steel Works is “® French patent Ch. A. Keller, No. 329,013, February 2, 1908. June 3, 1909 of the type with four vertical movable electrodes for earrying the current. Each electrode forms at its base a heating zone in which the temperature can be. regu- lated. Each pole carries two electrodes'in parallel. The construction of this furnace, Figs. 1, 2 and 3, includes four principal groups or parts: a. The movable furnace body, simply a metallurgical vessel without any electrical connection whatever, with its support and suitable hydraulic movement. b. The rotatable electrode supports, with means for suspending the electrodes and making electrical connec- tion with the central block or tablet for distribution of electric current. These supports are completely inde- pendent of the furnace body, and when they are all turned outward the cover of the furnace may be easily lifted or removed. c. The overhead system of bus bars for distribution of current, with fixed laterals for the movable connec- tions to the revolving electrode brackets. d. The conirol board for the electrodes, with suitable valves for distant control, and the measuring instru- ments. The movement of the electrodes is accomplished by means of hydraulic motors, and the following combina- tions can be made: Simultaneous raising of two elec- trodes of the same polarity or of the four electrodes to- gether. Simultaneous raising of two electrodes of the same polarity and simultaneous lowering of two clec- trodes on the cther pole. Raising of one electrode and simultaneously lowering of the other electrode of same polarity. Separate movement of any electrode. The regulation of the electric circuits is obtained very simply in the following manner: 1. Regulation of Voltage-—For voltage regulation the two electrodes of same polarity are moved simultane- ously ; if there is simply an inequality of voltage between the two poles, the two electrodes on each pole are simul- taneously moved up and down with respect to each other. ‘Thus, by a single maneuver, the balancing of voltage is accomplished. These combinations for maneu- vering the electrodes are very simply realized by a suit- able arrangement of gears commanding the valves of the hydraulic motors. 2. Regulation of Amperage.—The amperage is equally divided between the four electrodes by means of their separate movemert; if there is simply an inequality of amperage between two electrodes of the same polarity, there is a simultaneous and inverse movement of these two electrodes. Thus also by a single maneuver the am- perage is balanced between the electrodes. This method of regulation, by balancing of the voli- age or amperage of one group of electrodes with the other, or of One electrode with the other of the same group, enables the use of a very simple and rational con- troller. I have applied, for the distribution of current to the furnace, an arrangement which I have called “ radiating electrical distribution” (distribution electrique rayon- nante *), which enables me to reduce the self-induction to the lowest possible limit. As I said before, the two electrodes of same polarity are in parallel, The total current is brought to the cen- ter of the furnace, above all its mechanical parts, by a system of interlaced copper bars, connected to a central block firmly held by the metallic supports of the frame- work of the furnace. From this block four electric cir- cuits radiate, each carrying two connectors for each elec- trode; one of these connectors is always idle. By this arrangement are obtained eight terminals, by means of suitably fitted copper bars, each group consisting of 10 needed for replacing an electrode. Metallurgical opera- trodes are suspended at the end of the jointed arms which carry the fittings for connecting the electrode cir- cuit to the connectors coming from the central block. The mode of distribution employed has the important advantage that it permits the replacing of an electrode while the furnace is running. The method of construc- tion described also reduced to several minutes the time needed for replacing an electrode. Metallurgical opera- * French patent Ch. A. Keller, April 28, 1908. THE IRON AGE 1757 tions may, therefore, be carried on without any inter- ruptions due to handling of the electrodes. When the rotating arms carrying the electrodes are turned outwardly, Fig. 1, the furnace body is entirely free of overhead encumbrances. The central connection block, which is placed high and out of the way, does not interfere with the lifting of the roof, the latter being rapidly done by means of the traveling crane which passed over the furnace. In this way any roof requiring repairs may be easily replaced by a spare one; further- more, the roof being lifted, repairs to the hearth itself are very easily made. The overhead central distributing system, having ra- diating branches placed directly above the electrodes, gives such low self-induction that tests made at the J. Holtzer Steel Works have shown that the value of cos ¢ was about 0.97 with a current of 12,000 amperes. Con- sequently this arrangement easily permits of the use of heavy currents under very favorable conditions and with- out fear of any serious lowering of the power factor. The incumbrances above the furnace are much dimin- ished by the use of a special fitting for the electrical con- nection between the electrodes and the overhead fixed terminals. Obviously the means of carrying the current between these parts should have a certain flexibility to permit of lowering and raising the electrodes. To avoid every chance possible of short circuits between the two poles in the movement of electrodes, and in view of the close proximity of the electrodes, I have adopted the following arrangement: * Very thin flexible bars, of 4 mm. thickness, for exam- ple, are attached at one end with the fixed conductors con- nected to the central bus bar system and with the electrode support. These flexible bars are divided into two sets, expanded and brought together again at several points in their length, where they are securely fastened. There is thus formed a series of flexible rings which contract and enlarge according to the position of the electrode. Where the bars are fastened together to complete each circle they are fitted with small rings which slide up and down on cylindrical rods, thus acting as a guide. This method of fitting produces a supple connection be- tween the bus bar terminals and the electrodes without introducing any overhanging protuberances larger than the natural transverse section of the electrode, thus leay- ing the space between the electrodes entirely free. The four electrodes entering into the working chamber of the furnace pass through an arched roof covering the furnace,+ The vessel containing the steel is circular in form and is lined with magnesite. The furnace body is supported on heavy steel runners, working on rollers, by which it may be tilted as desired. The tilting of the furnace may be in either the for- ward or backward direction for tafping the steel or the slag; this is done by means of hydraulic cylinders. The furnace body is fitted with openings in its cir- cumference for charging or watching the metallurgical operations. During working the gases generated in the in- terior of the chamber create a slight pressure; this con- dition is imperative to avoid all entrance of air, which would be prejudicial to the deoxidizing conditions wanted. The gases and vapors from the interior of the *French patent Ch. A. Keller, No. 387,462, May 6, 1907. +I have experimented with and put into practice on a large seale at the Livet Works an improvement in electric furnaces with electrodes in series; this improvement consisted in placing each electrode or each series of electrodes of different Lpereeey in a separate chamber (French patent Ch. A. Keller, No. 336,- 403, November 2, 1903). he two chambers thus formed were joined at the bottom by a canal filled with the metal being treat- ed and which might exist there, according to circumstances, in either the solid, pasty or liquid state. hen the metal in the canal exists in the solidified state we have a furnace having a lateral metallic pole very close in type to the furnace with con- ducting bottom previously described. The placing of electrodes of differing larity in separate chambers has the advantage of producing a furnace in which the electric current passes through the entire depth of the fused metal. Further, there is a benefit in construction resulting from having both poles formed by superposed electrodes. If in a furnace of the above described type the electrode in one of the chambers is lowered until it touches the metal con- tained therein, this hearth is, therefore, in short circuit, and by this fact the energy absorbed becomes nil. This variation in the method of operation of furnaces having separate chambers connected by a canal underneath has been used by Mr. Chaplet and the Société la Neo-Metallurgie (French patent Chaplet and Neo-Metallurgie, No, 270,005, September 25, 1906), for the con- reg ne of steel furnaces, applied at the Alevard Steel Works n Isere. 1758 furnace pass out through a pipe connected therewith and into a chimney having an adjustable draft. Results of Working of the Electric Furnace at the J. Holtzer Steel Plant. In Unieux steel is melted in an open hearth furnace, then poured into a ladle which is immediately emptied into the electric furnace. The molten steel is thus put in circuit and the operations of deoxidation, additional refining and adjustment of chemical composition carried out. The refining may be carried to: Sulphur and phos- phorus, 0.01 per cent. The regular practive gives sulphur and phosphorus about 0.015 to 0.02 per cent. The period of treatment varies, of course, with the quality of steel desired. As an example of regular practice, there may be quoted the following results abstracted officially and checked: Weight of charge put into electric furmace............ 7,500 kg. Mean energy generation during operation Period of working. .........-2.seeeeeeeeecerenees 2 h. 45 min. Composition of molten charge: Carbon, 0.15 per cent.; sulphur, 0.06 per cent.; phosphorus, 0.007 per cent. Carbon content sought................... 0.45 to 0.50 per cent. Analysis of product : Carbon, 0.443 per cent. ; sulphur, 0.009 per cent.; phosphorus, 0.008 per cent. es ee TU, oo iinet wntinc weep ccsanes 275 kw.-hr. Blectrode consumption, 18 mm. per hour for 4 electrodes having a cress section of 400 x 400 mm. For continuous working, and assuming the cost of elec- trodes to be 35 francs per 100 kg., this corresponds to a cost of about 4 francs (80 cents) per ton of steel. The labor on the furnace, including feeding of the necessary materials, was provided by three laborers and one melter. The regulation was manual and attended to by one of the three laborers, who looked after the repair of the fur- nace and the connection of the electrodes. The regulation could be carried on just as well by automatic regulators, but the regular behavior of the furnace, due to the ex- istence of two parallel hearths for each pole, made auto- matic regulation by no means indispensable. As another result of the metallurgical work of the Unieux furnace, I will quote, for example, a heat made for the production of 1000 kg. of ingots ordered from the Unieux Works by a foreign steel works. It required the manufacture of a steel or armor plate quality. The an- alysis of the steel supplied was as follows: Carbon, 0.30 per cent. ; silicon, 0.20 per cent. ; manganese, 0.56 per cent. ; sulphur, 0.007 per cent.; phosphorus, 0.013 per cent. The steel contained besides a certain quantity of nickel. The acceptance tests on these ingots were made on plates of 36 mm. thickness rolled to a width of 325 mm. The test pieces, 13.8 mm. in diameter and 100 mm. between marks, gave the following results: Ultimate Elastic limit. strength. Blon- * Pounds per Pounds per gation. square inch. square inch. Perct. D/d. 112,000 17.0 5.3 113,000 16.5 4.8 112,000 14.0 3.3 112,500 14.0 3.4 Notrr.—Apparently the longitudinal test means that the test piece was cut out with its longest dimension in the direction of rolling, while the transverse test piece was cut with its longest dimension perpendicular to the direction of rolling. Drop test on unnotched specimens : Longitudinal specimen. ON ook sg kay caps isipeceen 24 mm. Angle of rupture 7 . Longitudinal . Longitudina! Transverse specimen : Defiection at 15th blow Drop test on notched specimens : Longitudinal specimen. Ruptured at 7th blow. Angie of rupture Fracture Transverse specimen : Ruptured at 4th blow. Angle of rupture Fracture Fibrous. The drop tests were made on bars 30 x 30 mm., with the fol- lowing conditions : Unnotched bars: er OOS, 65k wea da SSCS odie nk snus 160 mm. Weight : SN Se NE cas wt sheen 6 Sia eee 4 ek ¥oues 6 cae 2.75 m. THE IRON AGE June 3, 1909 Notched bars: MPMEBTOS OF SUDPOTUR. «oo 5 oan esse kecewssevanes 100 mm. Weight ee OE NN es St is os Sad oS eeT be ws eee eeu 1.50 m. The treatment of the metal consisted in two temper- ings in water at a.clear cherry red on the unwrought, rolled and annealed plates. The qualities of these steels, both from the point of view of purity and that of various mechanical tests, are a proof that the electrode furnace forms a metallurgical apparatus in every sense of the term; a flexible appa- ratus which permits of precise metallurgical work; a new metallurgy, not because of the absolute material results obtained (for up to the present the quality and purity of the best crucible steels have never been surpassed), but because of the method used, which differs in no re- spect from that governing the operation of the open hearth furnace, perfected by new results procured by the high temperature and the neutral atmosphere which re- sult from the employment of an electric source of heat. I do not desire here to draw a parallel between the furnace without electrodes and the electrode furnace. But I cannot do otherwise than express the opinion that if we consider the simple and extensive metallurgical facilities provided with electrodes, and the small elec- trode consumption per ton of steel, we are led to ask how it can be argued that elimination of electrode (and a loss of some of the advantages which they possess) can constitute a determining factor in the adoption of a furnace without electrodes in preference to an electrode furnace. Again it must be added that the construction of elec- trode furnaces is very simple, and that the electrical equipment which supplies them belongs to ordinary every- day electric construction, and that the furnaces without electrodes are of complex construction, and that they cannot, as it seems to me, be left without hesitation to the ordinary workman. The Three-Phase Current, The electrode furnace should find its principal place in metallurgy in the direct application of three-phase cur- rents, for many steel works already have central stations supplying three-phase current. Finally, at the present day the transmission of energy is generally installed in the form of three-phase current, and, therefore, it is necessary to consider the use of this form of current in order to fill the demands of most cases which are pre- sented. These considerations have led me to a study of a three- phase furnace for the manufacture of steel. This furnace may be worked with electrodes connected in delta or star. In the first case, each of the three electrodes is con- nected respectively with each phase of the circuit; in the second case, the electrically reinforced part of the furnace which I have described is connected to the neu- tral point of the three-phase system. The three-phase electric furnace combines to a great extent the qualities of furnaces with electrodes in series and furnaces with conducting hearths if the connection is in star, for the molten steel is completely electrified and at the same time the electric current passing through the hearth is less than one-half the total current in use. It is possible to-day to approach without fear the construc- tion of a three-phase furnace having a capacity of 20 tons, which would necessitate the use of about 1800 kw. Such a furnace would be capable of purifying 250 to 300 tons per day of ordinary steel from the basic Bessemer converter in a series of heats which would last about 1% hr. each, and which would bring the sulphur content of the molten steel from the basic converter from 0.08 to 0.02 per cent. approximately, at the same time per- mitting of deoxidization and decarburization as required. The cost of work of this kind would vary from 15 to 20 francs per ton of steel treated, calculating electric en- ergy at 0.015 francs per kilowatt hour, a price which may be reached with gas engines supplied from blast fur- naces if no value is assigned to the gas and estimating the other factors of cost at a price corresponding to their usual value. The passage of steel through the electric furnace where, under the influence of superheating, it would be aia nase ee 7c anche a June 3, 1909 subjected immediately, and by a rapid process, to a marked desulphurization, would permit the use in the converter of a pig iron richer in sulphur. This advan- tage would enable a metallurgical plant taking advan- tage of this circumstance to use ores which otherwise would have been réjected, and thus the introduction of the electric furnace in such a plant would have a two- fold and important economic application. The possibility of economically interpolating the elec- tric furnace in the general cycle of great metallurgical operations should open a new era: that in which the em- ployment of the so-called ordinary qualities of steel is gradually abandoned. In giving to structural steel and rail steel additional qualities of safety, the electric fur- nace will contribute to the realization of a higher civiliza- tion by diminishing in great part the probabilities of catastrophes due to defects in quality. There can be no doubt that, impelled by their traditional initiative and by the sense of the imperious necessity of always doing bet- ter, the metallurgical works of the highest class will shortly take up the method of electrometallurgy. Nor is . it to be doubted that great public or private authorities, conscious of the responsibility and obligation which humanity imposes upon them above all, will soon base their requirements as to steel on the new guarantees which the most recent progress of modern technology re- veals to them through electrosiderurgy. ———>+-- oe __ The Maxwell-Briscoe Bids on Material and Supplies. Considerable interest was shown by purchasing agents and machinery and supply dealers in an advertise- ment which appeared in The Iron Age of March 18 last and in two other trade journals calling for bids on thousands of dollars’ worth of material and supplies for the Maxwell-Briscoe Motor Company, Tarrytown, N. Y. On April 1 The Iron Age detailed the result of this inno- vation in buying methods, which showed, according to E. R. Gormully, purchasing agent for the company, that considerable office detail and correspondence had been saved through the advertisements. All of the bids for the equipment listed are now in and they include propo- sitions from 248 different manufacturers, directly trace- able to the advertising. Mr. Gormully is convinced that some very advan- tageous contracts he has placed have been due to the publicity he gave to the company’s wants. The replies he received to the advertisements disclosed a wide differ- ence in the prices demanded, especially in some lines. For instance, the bids on chrome nickel steel, made ac- cording to specifications prepared by Mr. Gormully, ranged from 6% to 13% cents per pound. The bids on cone steel, of which the company required 50 tons, ranged from 4.90 to 11 cents per pound, and the order was placed at 6% cents per pound, the samples offered at below that price not being up to the specifications. Bidders for furnishing 50 tons of 3% per cent. nickel steel asked from 4% to 10 cents per pound. One of the most promising results from the bidding was the wide variety of prices asked for furnishing gear steel accord- ing to Mr. Gormully’s specifications. Seven companies, all prominent manufacturers, put in bids on this ma- terial and they asked from 2.40 cents per pound all the way to 15 cents. The contract, which called for 200 tons, was placed at 2.75 cents per pound. - On such material as 1000 tons of soft steel bar, 800 tons of malleable iron, and standard supplies, such as machine bolts, cap screws, carriage bolts, twist drills, &c., the bids were fairly uniform, and in such manufac- tured supplies as oil cans and guns, files, &c., the differ- ence in quality of the samples offered figured largely in the awarding of the contracts. ~~ The Harbison-Walker Refractories Company, Pitts- burgh, has been awarded a contract for the firebrick re- quired for three McClure hot blast stoves for the new blast furnace of the Worth Brothers Company, Coates- ville, Pa., also for 3,250,000 brick for 300 longitudinal coke ovens being erected by the Pittsburgh & Westmoreland Coal Company, Pittsburgh. THE IRON AGE The Sterling 24-In. Tool Grinder. A new tool grinder of simple construction manufac- tured by the Sterling Emery Wheel Mfg. Company, Tiffin, Ohio, is equipped with a special device to furnish a good supply of water when in operation. As soon as the ma- chine stops the water drains out of the wheel, leaving it dry and in balance. The machine may be used as a dry grinder by removing the small belt on the left hand side. Each grinder is equipped with a 2 x 24 in. grinding wheel of special material. The machine can be arranged to carry a wheel 3 in. thick if necessary at slight addi- tional cost. The floor space of the machine is 30 x 45 in., and the hight to the center of the arbor is 37 in. The self-oiling The New 24-In. Single Wheel Tool Grinder, Built by the Sterling Emery Wheel Mfg. Company, Tiffin, Ohio. bearings are 1% x 7 in. The driving pulley is 10 in. diameter by 4% in. face, and the flanges for the wheel are 12 in. diameter. The weight of the machine com- plete with the countershaft is 900 lb. The drop of the countershaft hangers is 10 in.; the length of the shaft 32 in., and its diameter 1 5-16 in.; the tight and loose pulleys are 8 in. diameter by 4% in. face; the dri