US1849185A - Method of and apparatus for shaping metallic stock - Google Patents

Description

March 15, 1932. I E, GIACCIHINO 1,849,185

METHOD OF AND APPARATUS FOR SHAPING IETALLIC STOCK Original Filed Oct. 10, 1927 4 Sheets-Sheet 1 [7&1 4 5' 1 E fi A*L-L.J 2

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March 15, 1932. E GIACCHINO METHOD OF AND APPARATUS FOR SHAPING METALLIC STOCK Original Filed Oct. 10 1927 4 Sheets-Sheet Inueni'or. I iacchino,

MEZ/O March 15, 1932. E. GIACCHINO METHOD OF AND APPARATUS FOR SHAPING METALLIC STOCK .Original Filed Oct. 10. 1927' 4 Sheets-Sheet 3 l l lnll lullsl 1| 1; l .ll I l l I I I I I I l I PTlllllllllllllll FFIIIIIIII III 1| 1 l d wmw P 1 T .w 1HC i n m -kwflunnHUwwflHwH E w .H E m March 15, 1932. E. GIACCHINO METHOD OF AND APPARATUS FOR-SHAPING METALLIC STOCK Original Fil-ed Oct. 10, 192 4 SheetsSheet 4 Jhvenior:

' Ezio Gian-chino, fly 226x43 Patented Mar. 15, 1932.

UNITED STATES PATENT-I) OFFICE L EZIO emocnmo, or rams, FRANCE, ASSIGNOR 'ro SOGIETE HOLDING nns Bam'rs ET PBOCEDES GIAGCHINO noun. L BAucHAGE ELECTRIQUE, socn'zm ANONYME, or

METHOD or AND APPARATUS FOR SHAPING METALLIC srocx Original application filed October 10, 1927,Seria1 No. 225,232, and in tIaly November 9, 1926. Divided and this application filed June 28, 1930. Serial No. 464,605.

It has been proposed to forge by electricity iron and steel bars by heating them through the electric current by the Joule effect and apparatus have been devised for carrying out said process.

Such apparatus consist chiefly of two distinct parts electric current the necessary pressure against a stop member serving as anvil in order to.

deform and thereby forge the work piece.

The mechanical members are chiefly a stop member, (anvil) this being one electrode, against which the bar is pressed for forging; a guide member for the bar, this being the other electrode working with a sliding contact and a pressure device acting upon the bar in order to produce its deformation in the heated zone. v

The electrodes have received heretofore a number of different forms; the latest machines are fitted with an electrode serving as anvil provided with adjusting and centering means in order to fix its position exactly with respect to the other electrode before begim ning the forging process and with an 'elec-. trode guiding the bar comprising smooth l bearings which must fit exactly thework piece on which they are closed with a certain pressure, the bar sliding in said bearings with a sliding friction when it is pressed against the former electrode;

During the forging process-both electrodes are unmovableone with respect to the other and forging takes place bythe formation of a bulb having approximately the shape of an ellipsoid of revolution, the largest possible size of said bulb is limited by the distance previously determined between the electrodes,

this distance being always rather small in order to avoid the lateral bending of the'bar.

'In these machines provided with the last improvements devised heretofore, the forged portion has constantly the shape of an ellipsoid of revolution, which is the only one'attainable as the bar is .pushed against a stasible to keepthe bar stationary and to move both electrodes simultaneously maintaining their'relative distance unaltered, the result, 7

however, would be unchanged.

1 By these machines it is not possible to forge large pieces nor to exceed certain limits in the ratio between the mass of upsetmetal and the bar size, as the temperature of the work piece in the forging zone rises rapidly till the metal burns and the bulb of upset-material becomes detached; the distance between the electrodes, which is unvariable during work, cannot be but very small as thebar to be upset would otherwise (as above stated) bend under the end load and the forged piece would be eccentric.

Even working within the above mentioned narrow limits admissible in such machines, great care must be taken in order to avoid burning of the workpiece especially when forging special steelas the known processes and apparatus do not allow of an easy and. reliable re ulation of the upsetting tempera- ;ture and pressure.

,This invention relates to a process for electrically forging iron and steel which'obviates the said disadvantages and allows of forging large pieces and upsetting large volumes of metal with respect to the bar, size; further to obtain jolted pieces of any form, either cylindrical or conical or having an outline formed by any broken line, this being of the utmost importance as it becomes ossible to effect in any kind of work an actua roughin out of the piece which has never been obtaine by the machines of the prior art.

According to this invention, during the forging'process the distance between the electrodes is increased until the heating circuit is broken} which allows, as shown hereinafter,

to work in a reliable manner even large pieces and to upset large volumes of metal with respectto thebar size, not exceeding in any case the dangerous temperature limit for a oiging result.

electrode with roller th tion known ie other the rod moe :ihout equal to that n 2111101. di-

e important ndmnto treat hers even :11" ch WtS impossible with the Fol-inning ti mounted on ode 0t 2 nent and hut SULil Whi i'ings is equal to that previou sidemtion of the tea iesize of the pie ection op- Ifhis system 0 by hearings give the tage that iti not drawn, ise smooth head tofore; [in anvil 01 feeding the curl ii in :1 ing an ohmic resist of the hm tinder t he this time. ther h; d

ances or both move here t0 ohtoin length of ained ei hm 16h de woi'l ment in the same direction as es hn y ettecting ieoti'ode 'WOIi nent allows moreover e ofi ie snee i he tro a1- advnnc t the 'WOl'k even it t is a certain an be obt guide electrode in a dir Which t her elec h or i e. t of the as the anvil or abu the pi n v des" t in st 1; hieh the h peec ning ontiece of a nose one has on ged for his result- 0 o the e to the 'lng the anvil or abu t in W Li iower 5 he displacenien piacinv orged our good execution o P ments at the same tnn o (a o i t that ins ie ni perm :1 mi 2 t J to p become point i'zmezoime hm em high enon ooh no nde in eon )hen ire

howeve tionelfle e the nm'il material u out o e shape I) t o1: it

3 t inoti on o L or ouiv of hall 7.

CL p16 eed o nnnbl 1 1 T 0 C H eentcrie taro e en i in th e sten 1' ten him: or-mine aceom p a n ztleziii and by construct one rannn .jniding in etch the ionie iii'nits QDSHIil a) 7 1 (1 5e of 11, mini own an] 51 n n d e i sonie d eta i 1 s;

ntioi jLbnOI'In eel heat ieniiy folui'e he maximum nnLi-( trodes IDOY- delete the Show "SE1 known a-ievtm i the i shm e. SilOW dizigi'nnii s hm'ii inve 1'; out 1:;

and

1 'fl'HiC T-F1U'1 J 7 tei res 3 to mg appliance nee ting oh upsott' eion begins;

he pm gain y const- ,i rmces,

1 y "-f'le necess' of the during is pro naintained redial:

J19 variations tne eonditi retoiore and 1 much smaller so th sh with which the bit-l anvil can be ing during work according to the principle formlng the object of this invention; in Figure 3 the electrode serving as the anvil or abutment is held stationary while the other electrode is moved during work in a directio-n'opposite to that in which the bar advances. I thus obtain a bulb of upset material having the same shape. as that obtainable through the known processes (Fig. 2) while completely eliminating the danger'of burning the metal and making it possible to jolt a much larger mass of metal with equal features of the machine and bar section, it being further possible to treat big pieces.

In Fig. 4 the anvil or abutment has been displaced during work at a uniform spee thus upsetting to a cylindrical shape. In Fig. 5 the anvil is made movable at successive constant and increasing speeds, whereby a forged piece is obtained consisting-of a plurality of cylinders having decreasing diameters suitably connected together. Figure 6 shows one of the many other forms of carrying out the forging process, this piece consisting of two spherical parts connected by a cylindrical portion and being obtained 'by hol ding the electrode working as anvil stationary through a short period in order to form the first sphere, then displacing it at a constant speed in order to form the cylindrical portion and holding it stationary again in order to form the second sphere.

In all these forms which permit upsetting of large metal masses I'convenientlv provide for the guide electrode to be moved in a direction opposite to that in which the bar advances, which becomes absolutely necessary when the anvil'is stopped. for considerable lengths of time during work as in the case ofFigtS. 1 4

Figures 7 and 8 showa diagram of the appliances according to this invention with their respective operating means with movable anvil andmovable guide electrode, respectively, for removing the electrodes from eachother during the upsetting process.

Figure 7 diagrammatically shows the transformer group employed according to the invention. 'Figure 8a shows. a. diagram of the appliances'according to this invention wherein both the anvil or abutment and the clamping or guide electrode are arranged for movement.

Figures 9 and 10 show in front elevation and plan view respectively a machine for forging and roughening out iron and )steel bars to pieces of any form even of large size.

Figure 11 is a' sectional view of a device adapted to adjust the motion of the electrode serving as anvil' during the forging'process and Figure 11a is afdetail view of acam of said device.

Figures 12 and 13 show in cross section and axial longitudinal section respectively a diagrammatical constructional form of the ball bearings of the vise of the electrode guiding the bar.

Figure 14 is a sectional view of the anvil against which the end of the bar under treatment is pushed.

As shown in Figures 1 and 2, according to the known machines whereinthe distance between the electrodes 2 and 4 is not varied during work, the segment A of the bar 1 with a constant section equal to the initial section of the bar held between the electrodes gradually increases from its maximum value determined by the distance between the electrodes (Fig. 1 at the moment in which work begins) down to a few millimeters (Fig. 2) at the end of the forging operation.

This verysmall portion to which the bar segment held between the electrodes is reduced towards the end of the work'(Fig. 2), being in nearest proximity to the electrode 4 strongly cooled in which the bar is subjected owing to a well known phenomenon to a rise in temperature which is added up to the already much higher temperature, than the initial one due to the Joule effect which inevitably brings aboutan alteration of the material, and affects, more especially in the case of steel, the zone connecting this segment to the upset portion, and in certain cases produces burning of the material or even melting of same in said zone and detachment of the jolted portion if the operation is carried on electrodes further apart, as this would bring about amongst other inconveniences the serious drawback that the bar portion Aicomprised betweenthe electrodes would be too long with respect to its section in consideration of the load applied thereto for jolting, so that the bar when being upset would bend laterally under the action of the end load and the piece would be deformed and therefore faulty. Moreover by the known means the upset piece can only show the approximative shape of an ellipsoid of revolution shown in the drawings, big pieces cannot-be treated nor can large volumes of metal with respect to the bar size be upset. I

According to this invention the distance between the electrodes is increased during the upsetting operation. so that there is always between the electrodes until the end of the upsetting operationja bar portion having a constant section equal to the initial bar section, about the same length as the original bar portion and in anycase such that it prevents the rapidrise of the current intensity thus obviating the above mentioned disadvantages so that the work can be prolonged inent after the heating current has heen cut off the cylinder 6 transmitting the pressure is discharged through the coclzc 7 thus pushing back quickly the upset her and the pl uin 8 is returned to its initial Working pesf; .cn redy'for a fresh upsetting treatment.

Figure 8 reterring to a modified for)? shows diagrammatically an opcnting incohnnisin for automatically displacing the i in order to move this letter apart from other electrocle during joltin To this n ml wring all the time required for torging large pieces and upsetting large volumes of metal Without risk of the temperature enceecling the limits required for a good forging result.

The gracluel incr zise of the distance hetween the electrocles during work absolutely avoids any lateral hencling at the inning the forging opeintion W" i VOlUHlGS of metal to be upset he her size 0" the electrode Working as the oose the vice 1- is rovictec 'ith incl i" "Wli: meshing With c entiel nion l0 s w on the other oi:

reel; 1 siitlehl met to the push rod .111}? according to eno'; "i in 4..

group coin ises inain trnn any profile by Way ct enenr i .1 eposite h with another to incling' 0: which. is cese the forged piece takes 1 ion i le 1r obtainable by the :inchines irno 7 a shape sinner ion with the entran the si e is possible, entl oil th.

. [ill 1 elk";

1 r ion herin been tlClO t n-tin? ercler:

Lllt} h. icing ecu Worl; 531838.

e 1 -1 d ttilet L ailOlvl l i l. n i Mull Oil by n rocl eel he liyclrnulic is nnshecl and cylinder 11c piston a;

A) that exerted i. is sliclehle 9n the real '0 ntljust exactly the meme 2 cock or valve 10 sha l he close trocle 2 servin es F'V' i i 3 i r, 1 mm the cynnuemining rressure to tire 33* 1 push reel 3; Within slicles lV/ll 2. ltleens are provide rain 8, t 1 creof canvenient height cf the czijan inc 7 uitlecl eh 'nst the anvil 2 torming l ct aperture of the "valve or cocl; electrode which the Work her 1 1*: 110 in omler to regulate the speeclv oi the an pushed. l clenotes the other electrode guid- "vi 9 the her an l shown on the drawings as he he ins anvil ornhutnient ineiixetl b0 he hett for simplicity s sn it direct ion in which the her advances through mechanical means shown in .ien Werlt Qisststionery asthe coclt 10* is closed :mcl the While it is ectuzily movable in piston 53 cannot move Within its cyirmler. its opposite to that l soon as the Cock 10 opens (this happening" e.

the beginning of the upsetting operation) the electrodes 2 and 4 begin to move from each. other. At t 1e encl of the upsetting treat- 0' Fig. '7 ancl .eig. 8a. 30 and 31 clenote two hydraulic accumulators, capable of maintznnlng a constant pressure during Work,

former having a higher pressure than the latter, and said pressure being liable to increase or decrease (according to the section of the work piecegand the features of the metal of which the piece is made) by operating a suitable pump not shown, The ac cumuletor 31 works with a closed cycle as described hereinafter and its pressure can be raised by opening the cock 32 interposed on the conduit 33 connecting both accumulators. 34 denotes the operating mechanism of the machine which can establish communication between the conduit 35 branched from the accumulator 30 and the conduit 36 opening into the outer end of the cylinder 6 thus thus possible to commence forging as soon as the bar has reached the temperature previouslyv determined as best suited to the pur-' pose, said temperature being gnaintained until the end of the, operation by the effect of the gradual drawing apart of the electrodes during working. v From the lower pressure accumulator 31 is branched a conduit 37 opening into the lower end of a vertical cylinder 38, in which a piston is slidable, the rod whereof is connected to a swing lever 39 acting upon the vice 4 of the electrode guiding the bar. The accumulater 31' thereby holds the vice 4 automati- 40 cally closed with a constant pressure.

Into the upper end of the cylinder 38 opens a conduit 40 that is connected throughthe operatingmechanism 34 with the conduit 35 and therefore with the higher pressure accumulator 30 thusopening the vise at the end of the work when the ,operatingmecb anism 34 connects the conduit 36 with the relief pipe 41 thus relieving pressure from the bar. The quick return of the push rod 3 is "5 produced by the fact that a branch pipe 37 of the conduit 37 constantly communicates with the end of the cylinder 6 opposite to that receiving the conduit 36 thus establish- 3 ing a counter-pressure on the ram 5.

When determining the workin pressure of the accumulator 30necessary orobtaining theldesired pressure of the bar I against the anvil, this counter-pressure constantly eierted-upon the ram 5 by'the accumulator cc has of course to be considered.

The cylinder 9 is filled withoil or other suitable" liquid which also fills completely the tubes 42 connecting the outer end of said cylinder- 9 with the end of another cylinder 43, in which is mounted the piston the mum, a piston p order to vary the throttling. action. The back other end whereof freely communicates with a branch pipe. from the conduit 37 and therefore with the low pressure accumulator 31. In the conduit 42 is inserted the'member operating the anvil 2, the section whereof is shown in the constructional formillustrated in Fig. 11. This member is acted upon by means of a hand wheel 45 and comprises a plurality of cams 46 keyed on shaft 47 of the hand Wheel, each consisting of a plurality of projections adapted to operatethrougli push rods 48 the successive openings of the valves 49. This arrangement is such that different positions of the hand wheel 45 cause one, two or more or all valves to open and as all the valves are inserted between the. connecting pipes 50 .and 51 of the apparatus with both tubes 42 branched from the cylinder 9 and from cylinder 43, respectively, it is possible, according as a smaller or larger number of valves open, to hinder more or less the flow of the oilfrom the cylinder 9 into the cylinder 43 and to obtain a higher or lower backward speed of the anvil 2. As the throttling ports situated in correspondence w1th each valve can be different from one another, awider range of anvil speeds can be obtained by all possible combinations in the opening of the valves. As a constant pressure trans mitted by the accumulator 31 is exerted upon the face of the piston 44 turned towards the conduit 37, the pressure transmitted to the anvil by the bar is also constant and a constant backward speed of the anv1 l corresponds to a given position of the ad ust1ng no mechanism 45. as

This latter has further a closed position of the conduit 42 in which any movement of the anvil 2 is stopped. At the end of the work, the pressure transmitted by the bar agalnst the anvil ceases and the pressure actlng upon the piston 44 and generated by the accumulator 31 causes the oil to flow back into the cylinder 9 (and therefore the anvil to resume its initial position) through he manimum section of the liquid flow in the ad ust1ng mechanism owing to the fact that all the valves open under the action of their respec- ,tive springs. The adjusting member can be made as a cylinder always inserted in the conduit 42 and provided with slots having a section increasing from naught to a maxisliding in said cylinder in flow of the oil would'be efiected through an.

,automatic valve provided on said piston.

In order to upset eccentric or inclined r curved pieces the machine is provided with an operating mechanism 56 for displacing the anvil 2 at will in a transversal direction.

Figures 12 and 13 show the'bearings of the vice for the guide and contact of the bar with rolling friction. The bar is shown as of circular section but it is obvious that the same bearings'can clamp bars having any other in wide limits. 52 denotes the bearings carrytilt , drawh ing the balls 53 and fixed to the vice. The balls 53 of each bearing 52 are lodged in two longitudinal races 54 parallel to each other and to the bar axis and obtained in the hearing itself. The balls are held in the bearings 52 by any known means e. g. by slightly upturning the edge of the bearings 52 that shall of course be situated beyond the plane passing through the center of the ball. Once the balls have been fitted in, the races 54 are closed by means of end plates 55.

It is clear that one race 54 only for both ball rows can be obtained in each bearing 52 when the size of the balls is such that they can be brought together until they contact. The balls 53 are fitted with a certain play into the race 54 in order to allow them of rotating freely and pressing all the balls for a good contact on the bar 1 under the clamping pressure of the vice.

It is clear that whatever be the size or shape of the bar 1 the Vice bearings always fit the bar automatically establishing a good contact on all the balls.

When the axial pressure is brought to act upon the bar 1 in order to eifect upsetting, the bar advances towards the anvil or abutment and the balls 53 roll upon the bar maintaining a good contact continuously renewed owing to the rolling of the balls which, as experience has shown, allow the necessary current intensity to flow through without any considerable heating of the contact points and with a rolling friction without bringing about any sliding effect.

With the bearings according to this inven tion it is possible to heat treat hars even not drawn and a great economy is realized with respect to the systems employing smooth sliding bearings with sliding friction as in the prior machines which had to be fitted with a very large and expensive number of bearings suiting all sizes and forms of the bars and requiring frequent repairs and changes owing to the scratches frequently caused on their inner surfaces by small chips, burs or foreign matter on the drawn bars. The bearings with sliding friction show another dis-- advantage i. e. quite small. differences in the bar diameter that are be found even on drawn bars affected the contacts enormously, burning the worlr piece laterally. All such lrs are fully removed lay the bearing no; to this invention,

C re 14 shows the improved electrode we use; as anvil,

The head of the anvil 2 is simply fitted upon the rod 8 receiving the electric current, and is made of a material having about the same ohmic resistance as the material of which the relates the bar 1, such diameter being such that its temperature owing to the flow of the electric current reaches a value lower than that of the temperature of the bar 1 but still high enough (e. g. one half of that reached by the end of the bar itself). In this case the objectionable heat substraction at the bar end during forging that takes place in the known machines is done away with.

The material of which the anvil is made shall obviously have a suliicient mechanical resistance in order to prevent its permanent deformation during the pressure exerted thereon by the bar end during upsetting.

What is claimed is:

ll The method of forging metallic stock which consists in positioning the stoclr be tween guide and abutment electrodes, passing an electric current through portions of the stock to be worked of sufficient intensity to raise the stock to forging temperature, applying suficient pressure to the stock in the direction of one of the electrodes to change the profile of the stock, and moving the guide electrode in a direction awayfrom the abutment electrode during the forging treatment.

2. The method of forging metallic stool; which consists in including the portion of the stoclr to be worked in an electric circuit and between two electrodes, one serving as change profile of the stoclr, and moving the guide electrode in a direction oppos the pressure during the forging ment.

3. The method of forging metallic stock: which consists in including the per i stock to be worked in an electric ircui between two electrodes, heating the electrically to forgin temperature, on longitudinal pressure to the stochin rection of one of the electrodes to ch profile of the stoclr, and relatively said electrodes at varying speeds dur forging treatment.

4. The method of forging meta lic which consists in including the port. the steel: to be worlred in an electric c between two electrodes, heating th electrics to forging temperature, longitudinal pressure to the stool: rection of one of the electrodes to cha profile of the stoclr, and increasin hetween said electrodes i speeds during the forging treatm The method of forging me, which consists in including the portr steel; to he worlred in an electric circu between two electrodes heating electrically to forging temperature, 1 longitudinal pressure the stool rection one of the electrodes to or,

other electrode during the forging treatment.

6. The method of forging. metallic stock which consists in including the portion of the stock to be worked in an electric circuit and between two electrodes, heating the stock electrically to forging temperature, applying longitudinal pressure to the stock in the direction of one of the electrodes to change the profile of the stock, and increasingthe distance between said electrodes at accelerating speeds during the forging treatment.

7. The method of forging metallic stock which consists in including the portion of the stock to be worked in an electric circuit between'two electrodes, heating the stockelectrically to forging temperature, applying longitudinal pressure to the stock in the direction of one of the electrodes to change the profile of the stock, and moving one of said electrodes at an accelerating speed away from the other electrode during the-forging treatment.

8. The method of forging metallic stock which consists in including the portion of the stock to be worked in an electric circuit between two electrodes, heating the stock electrically to forging temperature, applying longitudinal pressure to the stock in the direction of one of the electrodes to change the profile of the stock, increasing the distance between the electrodes, and arresting the increase of distance between the electrodes during the forging treatment.

9. The method of forging metallic stock which consists in including the portion of the stock to be worked in an electric circuit between two electrodes, heating the stock electrically to forging temperature, applying longitudinal pressure to the stock in the direction of one of the electrodes to change the profile of the stock, and increasing the distance between the electrodes at a given speed, at a higher speed, and then at a speed less than the higher speed .during the forging treatment.

10. The method of forging metallic stock which consists in including the portion of the stock to be worked in an electric circuit between two electrodes, heating the stock electrically to forging temperature, applying longitudinal pressure to the stock in a direction of one of the electrodes to change 'the profile of the stock .and increasing the distance between the electrodes at successive-- 1y increasing constant speeds during the forging treatment.

11. The method of forging metallic stock which consists-in including the portion of the stock to be worked in an electric circuit between two electrodes, heating the stock electrically to forging temperature, applying longitudinal pressures to the stock in a direction of one of the electrodes to change the profile of the stock, and increasing the distance between the electrodes at a given speed and at a greater speed during the forging treatment.

13. The methodof forging metallic stock which consists in including the portion of the stock to be worked in an electric circuit between two electrodes, heating the stock electrically to forging temperature, applying longitudinal pressure to the stock in the direction of one of the electrodes to change the profile of the stock, and increasing the-distance between the electrodes at a given speed and at a lower speed during the forging treatment. 14. In an apparatus for electrically forging a metal bar, fluid-actuated means for progressing the bar, an accumulator maintaining said means under differential fluid pressure, a hydraulic piston, an anvil carried thereby, means for controlling the .retracting movement of the piston under the progressive movement of the bar, a clamping electrode arranged between the pistons, a piston to exert clamping pressure on the electrode under differential fluid pressure, means to control the fluid pressures in the pistons and means to move the clamping electrode in a direction opposite to the movement of the bar.

15. In an apparatus for electrically forging a metal bar, the combination with a clamping electrode for sliding contact with said bar, a bar-clamping electrode serving as anvil to engage one end of said bar and means for feeding said bar towards the anvil; of means for maintaining during operation a constant bar pressure against the anvil corresponding to the unitary pressure required for producing the permanent deformation of the material at the temperature best suited for obtaining good forging results multiplied by the bar section, and means for displacing the clamping electrode during forging in a direction opposite to that in which the bar advances. a

16. In an apparatus for electrically forging ametal bar, the combination with a guide electrode having sliding contact with said bar, an electrode serving as anvil adapted to engage one end of said bar and means for moving' said bar toward the anvil; of means for displacing the guide electrode independently of the anvil during forging in a direction opposite to that in which the bar advances.

17. In an apparatus for electrically forging a metal bar, the combination of an electrode engaging said bar, an electrode serving as an abutment to contact with one endrof said bar, asource of electrical energy associated with said electrodes for heating the bar to forging temperature, and means for applying to the bar in the direction of its length'a predetermined and limited pressure whereby the forward movement of said bar ceases whenthe resistance to the forward movement of the bar exceeds said predetermined pressure 18. The method of forging metallic stock which consists in including the portion of the stock to be worked in an electric circuit and between two electrodes, heating the stock electrically to forging temperature, applying a predetermined longitudinal pressure to the stock in the direction of one of the electrodes to change the profile of the stock at forging temperature, said pressure beinginsuficient to deform the stock when at a temperature less than forging temperature.

In testimony whereof, I have hereunto suloscribed my name.

EZIQ GIACGI-lltllth mamas

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