US2151914A - Welding apparatus - Google Patents

Description

March 28, 1939.

R. K. HOPKINS 2,151,914

WELDING APPARATUS Filed Sept. 16,1936 2 Sheets-Sheet 1 INVENTUR ROBERT K. HOPKINS 7- fiw ATTORNEY March 28, 1939. R. K. HOPKINS WELDING APPARATUS 2 Sheets-Sheet 2 Filed Sept. 16, 1956 FIG. 3

m 0 B 6 H 6 l. 9 6 3 4433 211 m. a? 4M4 s 7 o E... 2 im 1 n w 5 9 a M 4 a T o 3 TTORNEY ?atented Mar. 28 1939 t MED STATES PATENT OFFICE LDING APPARATUS Robert K. Hopkins, New York, N. Y assignor to M. W. Kellogg 00., New York, N. Y.', a corporation of Delaware Application September 16, 1936, Serial No. 101,103

14 Claims. (01. 219-8) This invention relates in general to electric In accordance with my invention I employ as fusion of metals and in particular to the electric an electrode a metallic member, in the form of a fusion of metals for welding, veneering, and simsolid or a hollow body, that is made up of the ilar purposes. major portion of one or more of' the constituents .5 This application is a continuation in part of my of the metal it is desired to deposit, and separateapplication filed February 18, 1936, Serial No. ,ly feed to the gap between the end of the electrode 64,496. and the work, or in the vicinity of said gap, in the In arc welding, as at present carried out, and in form of granules, pellets, wire, and the like, pref the veneering, or coating, of metallic surfaces by erably through the electrode when it is a hollow 10 electric arc deposition of metal as disclosed in my body, the remainder of the constituents required 10 application above identified, it is generally necesto produce the desired deposited metal. The elecsary to employ as an electrode a body having a trode and the granules, pellets, wire and the like, special composition so that the weld metal, or the are fed to the gap between the end of the elecveneering metal, may have the required compositrode and the work, at such rates that at subtion. The electrode is made of special composistantially each instant the proper proportion of 15 tion primarily in order to obtain a weld metal or constituents is deposited to produce the desired a veneering metal of desired composition while deposited metal. Thus, with any set of con.. compensating for losses of the constituents of the stituents it is possible simply by varying the meltelectrode in the arc and the dilution of the metal ing rate and/or the rate of travel of the electrode deposited from the electrode due to its penetraand/or the rate or rates of feed of the granules, 20 tion into the metal being welded or veneered. pellets, Wire, etc., to obtain deposited metals of In the present cgmmercial practice, electrodes, widely difierent analysis.

Whether bare or covered, generally include all of The constituents of the desired deposited metal the constituents that they are to supply to the e pp d t0 the p between t e end of the final deposited metal in the core or metallic porelectrode and the Work, in their most economical 25 tion of the electrodes even though it has long been r Thus. for instance, When e si ed (18- proposed, in patents and in the literature, to inposited metal is an iron alloy the electrode is clude some of these constituents in the coatings made of mild steel or other equally cheap and of the electrodes. The proposals have not been readily available material. If the desir d decommercially successful because of the difiiculties posited metal includes chromium, the chr mium 30v involved in obtaining from the proposed elecn t t entm y be suppli d as granular ferrotrodes a deposited metal in which the constituents chrome or similar chromium compound or al y; included in the covering are found in proper promaganese may be s pp as fi a a s portions throughout, nickel as a metallic nickel wire, ribbon or pellets, Electrode metal is usually much more costly etc. I 35 than other metal of generally similar analysis. It is an object of this invention to provide The high cost of electrode metal is due in part to simple and inexpensive apparatus for depositing, th m l quantities that are made p t n im under the influence of the new of electric current and the difiiculties encountered in comp u through a gap between the end of an electrode some of thespeclal analyses; The 00st of B180- and the work, metals of different composition, 40 trode metal s always many tlmeimole t h or metal of substantially constant composition total cost of its constltuents in their read1ly avallbut underdjfl re t c'onditions of deposition from able commercial forms. Furthermore, while eleca Set of constituents whereby by Varying the feed trod? metal of Wlde Vanety of analyses m be of any or all of the constituents the required proobtalned all desnable analyses are not available. portions of the constituents to produce the This is articular] true of chromium allo s of high ch bmium col itent and of chromium glloys g metal 15 substantlany constantly eposl e of low carbon content.

I have found that it is not necessary in order It 15 also i oblect, of thls mventlon to provide to obtain the results of the prior art to incorslmple and mexpFnslve apparatus for depositing 50 porate n of the constituents of the finally, metal under the lnfluence of the flow of electric posited metal into a metallic electrode, but that current through a gap between the end of an' all of the results of the prior art and results not electrode and the Work, in which t e constituents obtainable by the prior art, may be obtained in are fed to the gap in their most economical forms a simple and much more inexpensive manner. .at controlled rates to substantially constantly'55 vide simple and inexpensive apparatus for depositing metal under the infiuence of the flow of electric current through a gap between the end of an electrode and the work, in which a hollow electrode of comparatively cheap and readily available material that includes a constituent, or constituents, 'of the desired deposited metal is used and the remainder of the constituents required to produce the desired deposited metal are supplied to the gap separately, but through or partly through the hollow electrode at such rate or rates that there is substantially constantly deposited the desired metal; the said remainder of the constituents are also preferably materials in their most economical forms.

The further objects and advantages or the invention will be better appreciated from a consideration of the following description of preferred modes and apparatus for carrying it out in practice together with the accompanying drawings, in which,

Fig. 1 is a part sectional front view of one form of the apparatus of my invention,

Fig. 2 is a fragmentary view of the apparatus of Fig. 1, illustrating the manner of adding electrode sections during the metal depositing operation,

Fig. 3 is a view similar to Fig. l, of a modified form of apparatus, illustrating the use of a plurality of electrodes, and

Fig. 4 is a view similar to Fig. 3, illustrating the use of a dead electrode.

The apparatus disclosed, as shown particularly in Fig. 1, includes a welding head Ill of the usual construction and arrangement mounted on a suitable support, not shown, so that it can be moved through a desired path relative to work 5. Work Ii may be mounted on an immovable support, also not shown, or it may be mounted on a support capable of movement in a predetermined path relative to welding head It]. Welding head In includes a current supply means, such as a welding current generator or a connection to a source of welding current, devices and arrangements for controlling the voltage and the amperage of the welding current, and an electrode feed motor that drives electrode feed. wheel l2, together with the usual devices and arrangements for controlling the drive of the electrode feed motor. It is to be understood that welding head In includes all of the usual arrangements and devices which are required for satisfactory operation.

Electrode feed wheel I2 is backed by an idler wheel [3 which serves to maintain electrode t in contact with feed wheel l2. One side of the current generator, or current supply means, is connected through cable IE to the work It, the other side being connected through cable It to a contact device that passes the electric current to welding electrode M.

While as explained hereinafter, other than hollow electrodes may be used, the apparatus of Fig. l is particularly adapted to the use of hollow electrodes. Electrode M, as shown, is mad-e up of a plurality of sections of convenient length which are easily connected together during the operation to form an electrode l4 of indefinite length. In this manner, there is no need to discontinue the operation in order to replace consumed electrodes. Each length of electrode It is internally threaded at each end so that it may be connected to the last section in the apparatus by screwing onto threaded nipple l8. The sections of electrode M as shown, are of circular cross-section butany preferred cross-section such as, square, elliptical, and the like may be used as preferred. Also, while the sections of electrode I 4 are shown as seamless, it is to be understood, that they need not have seamless walls but can be made of plate or sheet of proper thickness, shaped as desired, with the edges joined, or not as preferred. Electrode I4 is preferably bare but, if desired it may be coated externally or internally. When electrode i4 is externally coated, it is preferably provided with bare contact areas spaced along its length, and a contact device ll is provided that is arranged to pass the welding current through the bare contact areas.

Above welding head l0 and in line with the path of electrode I4, is supported hopper Hi, from which material is passed through the hollow electrode M to the gap between electrode l4 and work It. Hopper l9 includes a cylindrical body 20 and a conical bottom 2| that is provided with an orifice 22. Orifice 22 may be used to meter the material on its way to electrode M. In such case, orifice 22 is preferably adjustable to provide for variation in the rate of feed of the material. The material, which may be made up of one or more component materials, is passed to hopper l9 by means of one or more conveyor belts 23.

Conveyor belts 23 may be used as the metering means instead of or in conjunction with orifice 22. In such case, while conveyor belts 23 may be of any usual construction, they should be provided with means for moving them at a range of predetermined rates and also with means,such as knives 24, for maintaining a definite depth of material upon them. When the material is metered by belts 23, orifice 22 may be dispensed with, or made of such size that it will not impede the fiow of material out of hopper I 9. To prevent largesized particles of the material from stopping the flow through hopper I9, a screen 25 of suitable mesh is provided adjacent the top of hopper It.

In order to shut off the fiow ofv material out of hopper l9, as for instance at the end of the operation or during an interruption thereof, a valve 26 is provided which is adapted to seat on orifice 22. Valve 26 is mounted at one end of an articu- I latable bar 2?. The other end of bar 21 is connected to the armature of an electro-magnet 28 and to a spring 29f The arrangement is such, that the pull of spring 29 tendsto seat valve 28 and electro-magnet 28, when its circuit is closed, unseats valve 26. The circuit of the electromagnet 28 is opened and closed by manipulation of a button switch 30 located on the front of welding head It. The arrangement may also be such that the circuit of magnet 28 is automatically opened and closed with the opening and closing of the welding circuit.

The material passes from orifice 22 into a cylindrical communicating member 3i. Member 3| has its top united to the conical portion 2| of 'hopp'er l9 andsurrounds the lower end thereof.

Between the ends of member 3| is a diaphragm plate 32 that is provided with a central orifice 33. Windows or openings 55 are provided in the walls of member 3| above plate 32 to prevent changes in pressure in the space between the top of member 3| and plate 32 which pressure changes would effect the flow of the material. The top of plate 32 is provided with a conical recess to facilitate the passage of material to and through orifice 33.

Orifice 33 is larger than orifice 22 and is, of :ourse, also larger than an orifice equivalent to aelts 23, when belts 23 are used as the metering means, so that it will have no effect on the meter- .ng of the material. Orifice 33 may be closed to shut oi the flow of material to the lower end of nember 3| by a valve 34 provided for this pur- JOSE.

Valve 34 is mounted at one end of an articuatable bar 35. The other end of bar 35 is coniected to a spring 36 and to the armature of in electro-magnet 31. ;ending to remove valve 34 from contact with )rifice 33 and electro-magnet 31, when its circuit s closed, exerts a pull that overcomes the pull )f spring 36 and seats valve 34 on orifice 33. [he circuit of electro-magnet 31 includes a switch 38 that is mounted ona support member 39 adjacent the path of the electrode at a preietermined distance from feed wheel I2. Switch 38 may be of any preferred construction but should be such that it includes a spring pressed nember that is adapted to bear against electrode l4 to open and maintain the circuit open when ;he end of electrode I4 is above it and to close ;he circuit and maintain it closed when electrode I4 is out of contact with said spring pressed nember. A support member 46 is fixed a short iistance above support member 39 and has nounted on it a switch 4| similar to switch 38. Switch 4| opens and closes the circuit of an alarm means such as bell 42 that is intended to warn the operator of the machine, of. the approaching necessity of adding a section to elec- ;rode I4.

To the bottom of cylindrical communicating member 3| is hinged a funnel like member 43 whose spout 44 is, adapted to extend into the ipper end of electrode I4 to pass the 'material from communicating member 3| to the hollow :enter of electrode l4. Spout 44 is made of such a. length that it will extend to a point approxinately level with or preferably .a short distance aelow the spring pressed member of switch 38.

During the operation of the apparatus, whenever the end of a section of electrode I4 passes switch 4|, bell 42 will sound towarn the operator and call his attention to the fact that a new sectionmust be added to electrode I4.

When electrode I4 passes switch 38, electromagnet 31 will pull valve 34 onto orifice 33 and thus shut off the flow of material to funnel member 43. When the end of electrode I4 passes the end of spout 44, the operator will grasp spout 44 and swing it out of position as shown in Fig. 2 and pass a new section of electrode I4 over spout 44'. Spout 44 is then brought back to the normal position and the new section connected to the last section of. electrode M by screwing the sections together on the threaded nipple I8. When the new section is swung back to the normal position and into contact with switches 38 and 4|, the circuits controlled by switches 38 and 4| will again be opened, bell 42 will stop sounding and valve 34 will be pulled off orifice 33 to reestablish the flow of the material. It is to be noted that orifice 33 is large enough so that it will quickly allow the material accumulated during the shut-off period of valve 34 to pass the funnel member 43. Since the operation just described is an extremely. simple one, it can be performed so quickly that there is in fact no substantial interruption in the flow of the material to the-bottom of electrode I4. And thus the overall quantity of the materialwill be supplied to the de- Spring 36 exerts a pull posited metal thereby maintaining the analysis uniform.

The apparatus shown in Fig. 3 includes the elements of the apparatus of Fig. 1, above described, and also electrodes 45 and 46, together with their feed means and current supply means. It is to be understood that while two electrodes 45 and 46 are mentioned, only one or more than two may be used. Electrode 45 is driven toward work II by electrode feed wheel 41 that is backed up by idler wheel 48. The motor for driving feed Wheel 41, as well as the control arrangements therefore, not shown, are located in back of the panel of welding head I. The current supply means for electrode 45, not shown, which -may be a Welding current generator or a connection to an outside source of welding current, together with the usual control arrangements, are located in back of the panel of welding head II). A cable 49 connects the current supply means to contact means 50 that is adapted to pass the welding current to electrode 45. The other side of the current supply means for electrode 45 may be connected to the work by a separate cable, not shown, or it may be connected by cable I5. Electrode 46 is driven towards the work I by electrode feed wheel that is backed up by idler wheel 52. The motor for driving feed wheel 5| as well as the control arrangements therefore, not shown, are located in back of the panel of welding head I0. The current supply means for electrode 46, not shown, which may be a welding current generator or a connection to an outside source of welding current, together with the usual control arrangements are also located in back of the panel of welding head I II. A cable 53 connects the current supply means to contact means 54 that is adapted to pass welding current to electrode 46. The other side of the current supply means for electrode 45 may be connected to the work by a separate cable, not shown, or it may be connected by cable I5.

As above stated, electrodes I 4, 45, and 46 may be separately supplied with welding current or they may all be supplied from a single source. It is also within the scope of my invention to feed all of these electrodes from a single feed motor, by connecting all three of feed wheels I2, 41, and 5| through a suitable train of shafts and gears to the drive shaft of a single. feed motor. The single feed motor may be controlled in accordance to the average characteristics of all three arcs or any one or the arcs may be 'used to effect the control. Also, the current and voltage control may also be effected in accordance with the average characteristics of all three arcs or any one of them.

Welding electrodes I4, 45, and 46 may be arranged on a line as shown or they may be arranged in any preferred manner, however, it is important that they be so closely spaced that all three of them deposit their metal in a single pool. Electrodes 45 and 46 may be of any preferred cross-section, they may be solid or hollow and they may be coated or bare. Electrodes 45 and 46 may be of the same analysis or of difierent analysis as required to produce the desired results.

The apparatus shown in Fig. 4 includes the elements of the apparatus in Fig. 1, above described, and also, provides means for feeding, what may best be called a dead electrode 56, to work II. Dead electrode 56 is fed to work II by a feed wheel 51 that is backed up by an idler wheel 58. Dead electrode 56 is driven by a motor,

electrode 56 may be solid or hollow and of any preferred cross-section and may be located in any position relative to electrode l4, however, it is important that it be located sufficiently close to electrode [4 that it will be fused by the heat generated byJJhe flow of welding current through the gap between electrode l5 and work .ll. Dead electrode 5'6 may be of any preferred analysis and while onlyone is shown any number desired may be used.

The feed motor for dead electrode 56 maybe dispensed with if desired and feed wheel 51 driven from the motor that drives feed wheel [2. If this is done dead electrode 56 may be fed at the same rate as electrode I4 or by the use of any of the well known variable speed ;drive arrangements it may be fed at any preferred rate. The apparatus of Fig. 4 illustrates the use of a dead electrode, however, it is'within the scope of this invention to combine the apparatus of Figs. 3 and 4 so that live electrodes, and 46, as well as dead electrodes 56 may be used with the hollow electrode of Fig. 1.

, any particular metal or alloy but in view of the wide use of steel and corrosion resistant alloys in the fabrication of metallic'articles, it will be disclosed in connection with the coating or ve nearing of steel with corrosion resistantalioys.

The article to be coated or veneered, work II, is substantially horizontally positioned beneath welding head ID with the point, where it is desired to start the first band of veneer 59, beneath the path of electrode I4. Electrode I4 is then fed to work II and agap starter such as a ball of steel wool, a sliver of graphite, an iron nail, etc., interposed between and in contact with electrode 14 and work II. A light frame 60 is placed around the area of work'll to be covered by the first band of veneer 59. Frame 60 is then filled with flux '62 to form a blanket of substantial thickness on work I I over and adjacent the situs of band 59.

Flux 62 may be any fusible compound, or mixture offusible compounds, that do not produce an objectionable amount of gas under the influence of the discharge ofthe welding current through'the gap between the end of electrode l4 and work H and do not substantially add any undesirable constituents to or remove any desirable constituents from the deposited molten metal. Silicates or the components of silicates in general are suitable particularly if they are dried or calcined or sintered prior to use. However, prefused silicates either neutral, basic or acid are sometimes preferred because of theirpronounced non-gassing character. Manganese silicate, iron silicate, calcium silicate, aluminum silicate, glass and the like, both alone and in mixture have been found satisfactory. While fiux 62 should be easily fusible its melting point should be high enough to assure that when molten it does not flow too readily but remains on, and in the immediate The novel method is not limited to vicinity of, the molten metal to form a heat retaiiging and gas excluding blanket for the molten me a1.

Flux 62 is preferably used in'the granular form and while great variation is possible in the size of the flux particles, it is at present preferred to employ a flux the particles of which vary from powder size to ,4; of an inch and more. The

- blanket of flux 62' is preferably of a. depth sumcient to "submerge the arc, i. e. prevent the visuai and audible manifestations of an are from being apparent, and present a substantially quiet top layer of flux. 'It is my present belief that when an arc is submerged it lsnot extinguished and that the welding heat is generated by the arc discharge rather than by the passage of the welding current throngha pool of molten flux. However, as this application is a disclosure of fact, it is to be understood that I am not to be bound by any theory or hypothesis as to what takes place beneath the surface of the flux blanket 62. Flux 'blankets62 varying in depth from one inch or less to six inches and more have been found satisfactory. To obtain band 59 with substantially straight edges strips 6| may be used. Strips 6| are located near the desired position of the edges of band 59 and enough space is allowed so that the molten metal does not contact strips 6!. Strips 6| restrain the flow of the flux and thus restrain the molten metal.

After the blanket of flux 62' is positioned the various control arrangements are adjusted and set. to maintain thepredetermined voltage and amperage, which in turn maintains a predetermined melting rate of electrode and rate of travel along work ,i I, as well as the predetermined rate of feed of the material from hopper l9 to and through hollow electrode I4. The welding current circuit is then-closed. With the submerged are extremely high energy values may,

be used, thus k. w. and more may satisfactorily be used with electrodes of about diameter. The initial flow of current takes place through the arc starter which upon being consumed leaves a gap between the end of electrode [4 and work H. The current flow through the gap melts the suriace of work II, the end of electrode l4 and some of flux 62. Since the fluxes mentioned specifically above, and practically. all known useful fluxes, are second degree conductors and hence have a substantial conductivity when molten, it may be that the molten flux forms all or a part of the current path between the end of electrode l4 and work II. If such is the case, the gap will be filled with molten flux and the welding heat will result from the passage of the welding current through the molten flux. However, if such is not the case, and the probabilities are that it is not, the molten flux will form abubble'in which an arc is present that plays between the end of electrode l4 and work ll. As the passage of current continues the metal fused from electrode l4 and from work I I, as well as the a metal that results from the material passing to the gap between the end of the electrode I4 and work ll coalesces into a unitary molten pool.

After the initial passage of current work II or welding head I0, or both, are moved to cause the molten metal to deposit on ,work II in the form of a wide band 59. When the work I l and electrode [4 move relative to each other the fiux melted by the welding heat remains on and covers the molten metal. Because of the heat retaining capacity or fiux 62 as well as the welding heat generated at the gap, the molten metal spreads work II. The operation is then allowed to continue until the full length or width, of work II is covered by band 59. It is of course to be understood that during the band depositing operation sections of electrode I4 are added as required in'the manner previously described. The remainder of the bands 59 required to completely cover the surface of work H are then deposited. The

procedure is the same except that only one strip 6| is used, on the side opposite to the already deposited band or hands 59, and the new bands 59 are so located that their contiguous edges overlap so as to assure a continuous and properly fused surface as well as proper fusion into .work ll.

1 The band forming operation with the apparatus of Figs. 3 and 4 is substantially identical with that just described and a detailed description of the operation with each of these apparatus is not thought necessary.

The penetration of the veneer 59 into work H,

' or as may be otherwise. stated, the amount of -(1) rate of travel of the electrode relative to metal of work II that finds its way into veneer 59, is an important factor in obtaining a veneer 59 of desired analysis. Penetration is affected by many factors among which may be mentioned,

the work, (2) the current density and total energy dissipation at the gap between the electrode and the work, (3) the temperature of the work and (4) the position of the work'with respect to the. horizontal. results in .a higher penetration than a low rate. High current densities give higher penetration than lower current densities; the same effect is noticed if the current density per unitof metal area is maintained constant and the area'of the electrode is changed, an electrode of small area will give a greater penetration than an electrode of larger area. For a given set of conditions the higher the temperature of the work, the greater the penetration obtained, thus the penetration may be increased by preheating the work. Also, for a given set of conditions the penetration may be varied by tilting the work relative to the horizontal. If the work is tilted so that the molten metal tends to flow down hill in,back of the electrode the penetration is increased; if the work is tilted so that the molten metal tendsto flow down hill ahead of the electrode the penetration is decreased. By controliiihg these factors almost any penetration desired? may be obtained. In

practice, penetrations ranging from 5 to 95% have been'obtained, i. e. veneers have been deposited that extended from 95 to 5% below the original surface of the work.

Because of the number of factors involved and the variations of each factor possible, no attempt will be made to set forth the specific manner for obtaining any particular penetration. It is believed that the above explanation will enable any skilled worker in the art to attain any desirable penetration in the range set forth.

In veneering steel with corrosion resistant alloys ordinary mild steel pipe with a carbon content in the neighborhood of 0.03% or less is a preferred material for electrode l4., The chro miiim. required is preferably supplied by using ferro-chrome as the material passed to the gap between electrode l4 and work ll through electrode l4. Ferro-chrome of commerce usually contains, in round numbers 70% chromium and 30% iron and can be obtained with carbon contents-ranging from 0.06% to 6.0%. When nickel In general a high rate of travel passed through hollow electrode I 4. The nickel may be metallic nickel in granular or powder form orit may be some suitable nickel compound or alloy in the granular or powder iorm.

It should be evident to anyone skilled in the art that a wide range of chromium-iron and chromium-iron-nickel alloy veneers are possible with the materials above mentioned simply by varying the penetration, the electrode feed, and the feed of the material passed through the electrode. In depositing any particular veneer, as for instance a 16% chrome veneer with a maximum of 0.12carbon a penetration which allows the desired results to be obtained is first. determined. With the work ll of 0.25 carbon steel a' 3 40% penetration is satisfactory. Thispenetration will cause work II to supply 40 parts, based on 100 as the total parts, of the iron to the final alloy and .10 part of carbon. If a ferro-chrome of 0.06 carbon is chosen the 16 parts of chromium required will be supplied by 22.8 parts of ferrochrome. This amount of ferro-chrome will sup ply 6.8 parts of iron to the'final alloy and 0.013 part of carbon. If a mild steel of .02 carbon is used as electrode I4, the remaining 37.2 parts of iron required will be supplied by an equal number ofparts of electrode M. The electrode I4 will in this case add .006 part'of carbon to the alloy. Thus, the final veneer will contain the 16% 'chromium required and will have a carbon content of. 0.119%. This analysis will be obtained by so adjusting and controlling the operation that 37.2 lbs. of electrode l4, and 22.8 lbs. of ferrochrome are alloyed with 40 lbs. of the metal of work H fused by the current discharge. It is to be noted here that there is a loss of constituents during the operation due to the absorption by the flux and other causes so that in order to obtain the results indicated it will be necessary to increase the quantities above the values given to take care of the losses. It is sometimes desirable to add some of the alloying constituents through flux 62 by incorporating them in .flux 62. In such cases the quantity of the materials fed to the gap will be modified accordingly.

With the materials specifically disclosed above a wide change in analysis of alloy is possible. Thus, the carbon content of the alloy may be reduced materially by using lower penetrations. The chromium content maybe varied by changing the relative rate of feed of the ferro-chrome and melting rate of the electrode. By choosing the proper-rates of feed and the proper penetra-- tion, chromium alloys may be deposited with .06 carbon and less and also with 26% chromium and more.

'In carrying'out the novel method of this ap-;

thus in depositing a high nickel, nickel-chrome-' iron alloy, the penetration chosen may be such that the base metal will supply the major proportion of the iron required. 'In such case it would be preferable to make the hollow electrode of pure nickel or some suitable nickel alloy. Thus,

' in interpreting this disclosure it is to be remembered that it contemplates the use of the materials for electrodes and feed materialthrough the electrode l4 best suited to give the desired results.

In using the apparatus of Figs. 3 and 4 the method above described is also carried out, however with these apparatus further variations of the method are possible. Thus, if it is desired to deposit an alloy having alloying constituents in minor proportions as, for instance, a 4-6 chrome steel, a portion of the steel required may be supplied through electrodes 45 and/or 46 and/or dead electrode 56. These apparatus are also suited to the cases Where cheap metal is available having a composition not very much different from the desired alloy. In the latter cases all or some of the electrodes may be made of the availa-,

ble material and the rest of the constituents required for the desired alloy fed through the hollow electrode.

, I claim:

1. In apparatus for depositing metal under the influence of the flow of electric current through a gap between the end of an electrode and the work, in -combination, a hollow electrode, means for feeding said hollow electrode at a controllable predetermined rate to the work, electric current supply means connected to the electrode and to the work, a hollow member adapted to extend into said hollow electrode, material metering means in communication with said hollow member adapted to pass material to said hollow member at a predetermined rate, and means for shutting off at will communication between said metering means and said hollow member, said shutting oif means being arranged to accommodate the material metered during the period that said hollow member and said metering means are out of communication and torelease said ac-- cumulated material to said hollow-member at a rapid rate when communication is againestablished.

2. In apparatus for depositing metal under the influence of the flow or electric current through 'a gap between the end of an electrode and the work, in combination, a hollow electrode including a plurality of connectable seotions,' means for feeding said hollow electrode at a controllable rate to the work, electric current supply means connected to the electrode and to the work, a hollow member adapted to extend into the top end of said electrode on its way to the work, a material metering device, and a hollow communicating member attached to said metering device, said communicating member having said hollow member hingedly connected thereto -whereby said hollow member may be swung out of the path of the electrode for the addition of new sections to the electrode as needed, saidcommunicating member including an operatable shutofi device adapted to cut off the flow of material from said metering device to said hollow member during the addition of electrode sections and to pass the material accumulated during the shutoff period at a rapid rate to said hollow member when communication is again established between said hollow member and said metering device.

3. In apparatus for depositing metal under the influence of the flow of. electric current through a gap between the end of an electrode and the work, in combination, a hollow electrode, including a plurality of connectable sections, means for feeding said hollow electrode at a controllable rate to the work, electric current supply means connected to the electrode and to the work, a hollow member adapted to extend into the top end of said electrode on its way to the work, a

material metering device, and a hollow communieating member attached to said metering device,

the addition of electrode sections and to pass the material accumulated during the shutoff period at a rapid rate to said hollow member when communication is again established between said hollow member and said metering device, said communicating member having pressure equalizing apertures therein to prevent changes in the metering and the flow of said material due tov changes of pressure in said communicating member and in said hollow member.

4. In apparatus for depositing metal under the influence of the flow of electric current through a gap between the end of an electrode and the work in combination, a hollow electrode, means for feeding said hollow electrode to the work at a controllable predetermined rate, current supply means connected to said electrode and to the work, a communicating member, metering means controlling the passage of material to said member, operatable means for stopping the passage of the material to said communicating member, a hollow member adapted to extend into the end of said electrode on its way to the work, said member being in communication with said communicating member and being adapted to pass material from said communicating member to said gap through said hollow electrode, operatable means in said communicating member for stop-. ping passage of material to said hollow member, said second mentioned operatable means being arranged to accumulate the material passing to it during the stoppage of communication between the communicating member and the hollow member and to pass said material to the hollow member upon reestablishment of communication, said hollow member being connected to said communicating member the connection being such that said hollow member may be swung out of and into the path of the electrode for the addition of electrode sections.

5. In apparatus for depositing metal under the influence of the flow of electric current through a gap between the end of an electrode and the work in combination, a hollow electrode, means for feeding said hollow electrode to the work at a controllable predetermined rate, current supply means connected to said electrode and to the work, a communicating member, metering means controlling the passage of material to said member, operatable means for interrupting at will the passage of material to said communicating member, a hollow member having one end in communication with said communicating member and the other end extending into said hollow electrode on its way to the work, said hollow member being arranged to be swung out of and into the path of the electrode to allow addition of electrode sections as required, a second operatable means for interrupting the passage of material to said hollow member, and means including econd operatable means to open communication rhen the end of the electrode again extends poseriorly of said point. I

6. In apparatus for depositing metal under the ifluence of the flow of electric current through gap between the end of an electrode and the ork, in combination a hollow electrode made up i connectable sections, an electrode feed means, lectric currentrsupply means connected tothe lectrode and to the work for passing electric urrent through said gap, material supply means,

movable hollow member in communication with lid supply means and adapted to extend into aid hollow electrode to feed material thereto for assage to said gap, said hollow member being lovable away from said electrode for placing of lectrode sections thereon and being movable into ne with said electrode for connection of sections iereto. 1 Y

7. In an apparatus for depositing metal under me influence of electric current discharge irough a gap between an electrode and the work,

1e combination with an electrode having a pasigeway, means for continuously feeding said lectrode to the gap, electric current supply leans connected to the electrode and the work, separate metal supplymeans, means for feedig metal from the metal supply means to the assageway in the electrode, means for interipting the supply of metal to the electrode withit varying the ultimate metal supplied to the 1p.

8. In an apparatus for depositing metal under ie influence of electric current discharge irough a gap between an electrode and the work,

ie combination with an electrode having a pas-.

lgeway, means for continuously feeding said ectrode to the gap, electric current supply means mnectd to the electrode and the work, a sepaite metal supply means, means for feeding metal om the metal supply means to the passageway in i8 electrode, means for interrupting the supply metalto the electrode, including a reservoir Ir accumulating metal supplied during the interlption period, said interrupting means adapted supply metal from ,the supply means and aclmulated metal without varying the ultimate etal supplied to the gap.

9. In an apparatus for depositing metal under ityiof electrodes positioned substantially transversely to the direction of relative movement of the electrodes and the work, one of said electrodes providing a-passageway, a separate metal supply means, and means. for controlling the feed of metal from the separate metal supply to the electrode having said passageway.

.11. In an apparatus for depositing metal under the influence of electric current discharge through gaps between a plurality of electrodes and the work, including in combination a plurality of solid electrodes and one electrode having a passageway, a separate metal supply means, and means for separately controlling the feed of said solid electrodes and the metal feed from said separate metal supply, and means-for supplying current to said electrode.

12. In an apparatus for depositing metal under the influence of an electric current discharge through a gap between an electrodeand a workpiece, including in combination, a conduit having a substantially unbroken periphery, said conduit being in the form. of a consumable metal elecpipe electrode of substantially unbroken periphery, means for feeding said electrode to the gap, current supply means contacting said electrode and the workpiece for passing current through said gap to fuse the electrode, a supply of metal in particle form, controllable'means for feeding said metal in said supply to said electrode for conveyance therethrough without substantial loss tov the gap beneath said flux to be fused thereat with the metal of the electrode.

14. In an apparatus for depositing metal under the influence of an electric current discharge through a gap betweenan electrode and a workpiece, including in combination, a conduit having a substantially unbroken periphery in the form of a consumable metal electrode, means for feeding said electrode to the gap at a controllable rate,

current supply means contacting said electrode and the workpiece for passing current through said gap to fuse the electrode, metal supply means, and separate means for feeding metal in said supply to said conduit-to be directed thereby to the gap to be fused with the metal of the electrode,

said separate means for feeding said metal being controllable to effect a rate of feed of the metal independent of the rate of feed of the electrode.

ROBERT K. HOPKINS.

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