US2300670A

US2300670A - Electrical metal fusing apparatus and method

Info

Publication number: US2300670A
Application number: US336340A
Authority: US
Inventors: Robert K Hopkins
Original assignee: MW Kellogg Co
Current assignee: MW Kellogg Co
Priority date: 1940-05-21
Filing date: 1940-05-21
Publication date: 1942-11-03
Anticipated expiration: 1959-11-03

Description

Nov. 3, 1942. K, op 'ms 2,300,670

ELECTRICAL METAL FU SING APPARATUS AND METHOD Filed May 21, 1940 wnr W9 INVENTOR ROBERT K. HOPKINS l2 BY A 15g V A ORZEY Patented Nov. 3, 1942 I ELECTRICAL METAL rusmc ArrAaA'rUs I AND METHOD Robert K. Hopkins, New York, N. Y., assignor to The M. W. Kellogg'Co New York, N. Y., a corporation of Delaware Application May 21, 1940, Serial N6. 336,340

' 10 Claims.

This invention relates to the electrical fusion of metalsand particularly to the type of operation in which metal is deposited by fusing its constituents at a gap through which electric current is discharged.

' In the electrical fusion of metals, wherein metal is fused by the discharge of electric current through a gap, it is the usual practice to employ an electrode, either of metal made up of constitucuts of the desired metal or of non-consumable material, as one terminus of the gap. The operation is most generally controlled by adjusting the end of the electrode relative to theother terminus of the gap as required to maintain an electrical discharge of substantially. constant characteristics. This adjustment is efiected by arrangements connected to the electrical discharge circuit which act upon the electrode feed the electrode to the gap at a constant rate and adjusting the electrical energy imput to the gap as required to fuse the electrode at a constant rate.

It is a primary object of the invention to provide a novel method, and novel apparatus for carrying it out in practice, for the electrical fusion 'of metals wherein metal is fused by the discharge of electric current through a gap between the end on an electrode and a conductive body, the electrode being supplied to the gap at a constant rate and the current discharged at the gap being varied inversely as the resistance of the gap varies to fuse the electrode at a constant rate.

It is also a primary object of the invention to provide a novel method, and novel apparatus for carrying it out in practice, for producing metal motor, or other equivalent means. By reason of the mass of the moving elements, andtheir necessary mechanical connections, this manner of control does not result in an instantaneous adjustment so that the characteristics of the electrical dischargeand'the fusion rate of the electrode are not maintained constant at predetermined values but actually constantly vary, or hunt, about the predetermined values. The variations are such, however, that they average and for any practical run the quantity of metal that will fuse can quite accurately be predicted. I

This manner of control, while satisfactory for operations in which the metal fused is derived from the electrode and the base metal, imposes limitations in operations wherein constituents of a final metal of a desired analysis are supplied from sources other than the electrode, or the base metal, or the electrode. andthe base metal, at

rates uneflfected by, the variations at the gap. In

' the latter operations, as-for instance, those contemplated in my prior Patent No. 2,191,471, it is necessary in order to secure uniform analysis with this typeof control, to operate under such condltlons that there is always present a sufllciently large body of molten metal to average up the variations in the supply of electrode metal.

The use ofthis expedient for avoiding nonuniform analysis does not ordinarily affect the efllciency of the process but, in special cases, imposes a limit on the speed at which it can be. carried out. Thus, when depositing a thin coating of alloy on a base metal the speed of traverse of the electrode over the base metal and the rate of production of the alloy must be kept down to the values at which asumciently large body of molten metal is present to average the varying rate of fusion.

I have found that superior results can be ob-' tained in the general type of operation and the mentioned limitation to the specific operation removed, for all practical purposes. by supplying.

of desired analysis by the fusion-of its constituents at a gap, between an electrode and a conductive body, through which electric energy is discharged, wherein one or more of the constituents of the desired metal are supplied to the gap in' the form of ametal electrode and another or others of the constituents are supplied to be fused with the metal of the electrode, from a source separate from said electrode, the electrode being supplied to the gap at a constant rate, the other, or others, of the constituents being also supplied at a constant rate and the electriccurrent imput to the gap being varied inversely as the resistance of the gap varies so as to fuse the electrode at a constant rate whereby the fused metal is made up throughout of a predetermined proportion of the constituents supplied by the electrode and the constituents supplied from the separate source. I

It is a further primary object of the invention to provide a novel method, and novel apparatus for carrying it out in practice, for producing metal of desired analysis by the fusion of its constituents at a gap, through which electric current is discharged, between an electrode and aconductive body, wherein one or more of the constituents of the desired metal are supplied to-the gap in the form of a hollow metal electrode and another mothers of the constituents are sup-. plied in particle form to the gap through the hollow electrode to be fused with the metal of the electrode, the hollow electrode being supplied to the gapat a constant rate, the material in particle form also being supplied at a constant rate and the electric current imput to the gap being varied inversely as the resistance of the gap varies to fuse the metal of the electrode at a constant rate whereby a predetermined propor-' 7 tion between the constituents supplied by the hollow electrode and the material in particle form is constantly attained in the fused metal.

The further objects and advantages of the invention will be apparent from a consideration of All the following description, taken with the accompanying drawing, in the single figure of which, is shown a front view of a preferred form of the apparatus of the invention.

The method and the apparatus of the invention are applicable generally to electrical metal fusing operations wherein metal is fused at a gap through which electric current is discharged between an electrode and a conductive body. Thus, they are applicable to seam welding, either of the open or submerged arc type, and when the defposited metal is of substantially the same analysis as that of the metal to be joined or is of different analysis from that of the metal to be Joined. They are also applicable to coating or veneering operations, 1. e., operations in which composite metal bodies are formed by depositing molten metal of one analysis on a surface of a base metal of a different analysis to unite the metals into an integral structure. Furthermore, they are also applicable to operations in which alloy bodies of a single analysis are produced.

I choose to disclose my invention in detail in connection with the manufacture of an alloy body of a single analysis throughout. Also, while the invention is not limited to the use of a hollow electrode; solid electrodes, composite electrodes, etc., may also be used, I will disclose it in detail in connection with a hollow electrode.

The electrical metal fusing machine I. with the exceptions of certain elements not necessary to the present disclosure approximates that disclosed in my prior Patent No. 2,191,476 and, hence, the common elements will not be gone into in detail here.

Machine I is supported on a suitable structure H for movement in all directions over mold l2. Mold i2 is shown as a water cooled metal mold, preferably of copper; however, any preferred mold suited to the particular operation may be employed, thus, even a refractory mold may be employed. When the invention is used in seam welding or in the coating of metal bodies, the bodies to be united or the base metal to be coated is substituted for mold -I 2.

Within housing It is the tube forming mechanism that converts flat strip i into the hollow pipe like electrode 15., Strip I4 is made of a constituent, or constituents, of the ultimately desired metal and is conveniently carried on reel Ii. The

formed hollow electrode passes from the tube forming mechanism through a contact nozzle II from whence it proceeds towards mold l2. A vibrator device It may be provided adjacent nozzle II to prevent clogging of the end of hollow electrode II.

The tubeforming mechanism is driven by shaft I! that is connected by gears, in gear-box 20. to the shaft 2| of motor 22. Motor 22, since it operates the tube forming mechanism, is the feed motor for hollow electrode l5 and in any particular operation is operated at a constant speed. To give the apparatus a degree of flexibility, so that it may be used generally in the type of operation contemplated, motor 22 may be of such kind that it can be operated at any speed within a predetermined range of speeds, or it may be a single speed motor and a speed changing device, not shown, provided between it and shaft ll of the tube forming mechanism.

Contact device I! is connected through cable 22 to one side of the output of generator 24, the other side of the output is grounded through cable 25 to metal mold l2. Generator 24 may be such as to generate A. C. or D. 0. current, as

preferred and will normally be driven as by motor 25.

The field windings of generator 2 are tapped by

wires

21 and 28 so as to place variable resistance device 29 in the field circuit. The arrangement is preferably such that device 29 is in series with the field windings. Device 29 may be of any preferred form but must function to cut resistance into the field circuit as the voltage across the output cables increases and cut resistance out of the field circuit as the voltage across the output cables decreases. A number of commercial devices suited for this purpose are available. I

have shown schematically a device 29 that will function as required.

Device 29 includes a resistance 30 that is connected to wire 28. The contact end of pivoted contact bar 3| is adapted to make contact with resistance 30 as it is moved over the surface of resistance 30 to change the ohmic value of the resistance .in the field circuit to thus alter the field excitation and, consequently, the current output of generator 2i. Contact bar 3| is connected at its pivot to wire 21. The other end of bar 2| is connected by suitable linkage to the metal core 32 of solenoid 23. Wires 3! and 35 shunt solenoid 23 across

cables

22 and 25. A spring 36 constantly tends to pull contact bar 3| to the zero resistance contact point.

On a platform 31 above housing ii are mounted metering devices 38. These devices are preferably of the type shown and described in my prior Patent No. 2,174,175, although metering devices of any comparable type may be employed. Six devices 28 have been shown but a greater or lesser number may be used as required. Each device 28 is provided with a hopper 29 in which is placed the particular granular material to be metered by the particular device. The metered materials pass into a common hopper ID from whence they pass through tube ll into the formed hollow electrode ii. The granular materials are alloys or pure metals made up of constituents of the final desired metal.

Metering devices 2! are driven by shaft 42 that is connected to the output of the combined clutch and speed changer box 42. The input of box 42 is connected to the shaft of motor 44. Motor 14 is of the constant speed type so that the materials metered are supplied into hollow electrode ii at a constant rate throughout the operation of the apparatus.

In the deposition of ferrous alloys such as the chrome-irons or the chrome-steels; chrome! nickel steels. etc., strip ll will usually be a low carbon iron or steel, Armco iron, for example, and the granular materlals supplied into hollow electrode i5 ferro-alloys such as ferro-chrome, ferromanganese, etc., or pure metal such as nickel, etc.

In the production of an alloy ingot of a desired analysis, knowing the analysis of the chosen material of strip H as well as the analysis of the chosen granular materials to be supplied into hollow electrode II, and the preferred fusing capacity of the apparatus, it is a simple matter to determine the metering rates of the granular materials and the feed rate of hollow electrode ll. Experience will indicate in each case the preferred resistance across the current discharge the bottom-of mold i2. To facilitate starting, the

hollow electrode is fed almost to-the surface of the metal plug and a wad of steel wool, or similar are starter interposed between the electrode and the plug. The electrode end, as well as the bottom of the mold, are then covered with a deep blanket of protective flux 45. The motor is the energized and the operation commenced, after the motor-generator set has come up to speed, by closing the generator output circuit and the circuits of

motors

22 and 44.

The initial current surge destroys the arc starterto establish a discharge gap, beneath flux blanket 45, between the electrode and the metal plug. As the initial fiow is at short circuit, the initial energization of solenoid 33 will be insufficient to pull contact arm 3| off the no re- 'sistance stop, however, as the gap forms the voltage rises and increases the energization of the solenoid so that contact arm will be moved over the resistance to cut it into the field circuit and thus reduce the current output of the generator. until the gap is brought'to the predetermined ohmic value; when the rate of fusion of electrode It will equal its rate of speed.

During the operation, for various causes, the.

resistance of the gap will change. When such changes occur the voltage in the energizing circult of solenoid 33 will change and bar 3| will be moved to change the resistance in the generator This movement of bar 3| will continue field circuit to vary the. current output inversely as the resistance of the gap varies. Thus, if the resistance of the gap increases, bar 3| will move to cut more resistance into the generator field circuit to diminish the current output until the resistance of the gap'is again at the predetermined value when the' decrease in voltage in the circuit of solenoid 33" will cause bar 3| to-retum to its previous position. If the resistance of the gap'increases bar 3| will move to remove resist ance out of the generator field circuit to increase the current output until the predetermined resistance of the gap is reestablished when bar 28 V will move back to its previous position. In this mannerthe fusion rate of hollow electrode It will be maintained constant for the full period of operation.

Since the granular materials are fedinto hollow electrode ii at a constant rate, the constituents supplied by hollow electrode l5 and the granular materials will constantly be fused at the gap in the predetermined proportions and the final metal will be of uniform analysis through? out. Furthermore, this result will be obtained without the necessity of maintaining a sufficiently termined resistance value of said gap to supply 1 tween its end and the conductive body, an electric large pool of molten metal to average varying rates of supply of the constituents.

In A. C. operations it will sometimes be preferable to substitute for generator 24 and its asso-' elated devices and arrangements, a transformer of low reactance. The transformer should preferably be so arranged that its reactance can be adjusted to the best values for selected discharge voltages.

when a low reactance trans- 7d connecting theoutput to contact device II and to mold I: should be kept to a minimum. Such" i a transformer, properly adjusted, and with an output circuit of low reactance, will automatically vary the current output inversely as the resistance of the discharge gap varies as required, to fuse electrode l5 at a constant rate.

I claim:

1. In metal fusing apparatus, means for feeu' ing a metal electrode at a substantially constant rate toward a conductive body for fusion by the discharge of electric current through a gap be tween its end" and the conductive body, electric current supply means connected to said electrode and said body for discharge of .electric current through said gap, and means for altering the electric current supply as required to maintain the fusion rate of said metal electrode substantially constant.

2. In metal fusing apparatus, means for feeding a metal electrode at a substantially constant rate toward a conductive body for fusion by the discharge of electric current through a gap bei tween its end and the conductive body, electric current supply means-connected to said metal electrode and said body for discharge of electric 7 current through said gap, said electric current supply means being adapted at a predetermined resistance value of said gap to supply electric current at th rate required to fuse said metal electrode at a rate equal to its rate 'of supply and means eifective to vary the rate of supply of electric current inversely as the resistance value of said gap varies to maintain the fusion rate of said metal electrode substantially constant.

3. In metal fusing apparatus, means for feeding a metal electrode at a substantially constant rate toward a conductive body for fusion by the discharge of electric current through a gap between its end and the conductive body, electric current generator means having one side of its output connected to said metal electrode and the other side connected to said conductive body for discharge of electric current through said gap, said generator means being adapted at a predeeleetric-current at the rate required to fuse said metal electrode at the rate supplied, and means effected by electric energy variations hi the output circuit of said generator means for varying the electric current output of said generator means as required to substantially constantly fuse said metal electrode at the rate supplied.

4. In metal fusing'apparatus, meansfor feed-. ing a metal electrode at a substantially constant rate toward a conductive body for fusion by the discharge of electric current through a gap becurrent generator including an excitable field having one side of its outputconnected to said metal electrode and the other side connected to said conductive body fordischarge of electricfcurrent through said gap, said generator being adapted at a predetermined resistancevalue of said gap to supply electric current at the rate required to fuse said metal electrode at a predetermined rate, and means actuated in accordance with electric energy variations in the output circuit of said generator for varying the excitation of said field inversely as the resistance of said gap varies'to vary the electrical output of said generator as required to substantially constantly fuse said metal electrode at the predetermined rate.

5. In metalfusing apparatus, means for feed- I former is employed the reactance of the cables ing a metal electrode at a substantially constant rate toward a conductive body for fusion by. the discharge of electric current through a gap between its end and the conductive body, an electric current generator having one side of its output connected to said metal electrode and the other side connected to said conductive body for discharge of electric current through said gap. said generator including an excitable field and a variable resistance means for varying the excitation of said field, said generator being adapted at a predetermined resistance value of said gap to supply electric current at the rate required to fuse said metal electrode at a predetermined rate, and means actuated in accordance with electric energy variations in the output circuit of said generator operatable to vary the ohmicyalue of said variable resistance means as the resistance of said gap varies to thereby vary the output of said generator as required to substantially constantly fuse said metal electrode at the predetermined rate.

6. In apparatus of the character described, means for feeding a metal electrode made up of constituents of the desired metal at a substantially constant rate toward a conductive body for fusion by the discharge of electric current through a gap between the end of the metal electrode and the conductive bochr, said feeding means being adapted to feed said electrode at a substantially constant predetermined rate, means for supplying further metal made up of constituents of the desired metal to the gap at a constant rate to be fused with the metal of the electrode, electric current supply means connected to said metal electrode and said conductive body for discharge of electric current through said gap, said electric current supply means being adapted to supply electric current at the rate required to fuse said metal electrode as supplied at a predetermined resistance value of said gap, and means eflective to vary the current supplied by said current supply means inversely as the resistance of said gap varies whereby said metal electrode is fused at a substantially constant rate and a predetermined proportion between the constituents of the desired metal supplied by said metal electrode and said further metal is maintained substantially constant throughout the operation of the apparatus.

7. in metal fusing apparatus, means for feeding a hollow metal electrode made up of constituents of the desired metal at a substantially constant rate toward a conductive body for fusion by the discharge of electric current through a gap between the end of the metal electrode and the conductive body, said means being adapted to feed said hollow electrode at a substantially constant predetermined rate, means for supplying metal made up of constituents of the desired metal in granular form through said hollow electrode to be fused at said gap with the metal of said hollow electrode, said supplying means being adapted to supply said metal in granular.

form at a substantially constant predetermined rate, electric current supply means connected to said hollow electrode and said conductive body for discharge of electric current through said gap, said electric current supply means being adapted at a predetermined resistance value of said gap to supply electric current at the rate required to fuse said hollow metal electrode as supplied and means effective to vary the current supplied by said current supply means inversely as the resistance of said gap 'varies whereby said hollow metal electrode is fused at a substantially constant rate and a predetermined proportion between the constituents of the desired metal supplied by said hollow metal electrode and said granular metal is maintained substantially constant throughout the operation of the apparatus.

8. In the electrical fusion of metals wherein metal is fused by the discharge of electric current through a gap between the end of metal electrode and a conductive body, the steps comprising. feeding a metal electrode at a constant rate to the gap, supplying electric current to the gap to fuse the electrode at the rate supplied when the resistance of the gap is at a predetermined value, and varying the current supply inversely as the resistance of the gap varies to maintain the fusion rate of the metal electrode substantially constant.

9. In the electrical fusion of metals wherein a metal of desired analysis is produced by the fusion of its constituents at a gap through which electric current is discharged between the end of a metal electrode and a conductive body, the steps comprising, feeding a metal electrode made up of constituents of the desired metal at a constant rate to the gap, supplying metal made up of constituents of the desired metal from a source separate from the metal electrode at a constant rate to be fused with the metal of .the electrode, the rate of feed of the electrode and the rate of supply of the metal from the separate source being so chosen that the constituents of the desired metal are constantly supplied in the required proportions, supplying electric current for discharge through the gap at a rate to fuse the metal electrode as presented when the resistance at the gap is a predetermined value, and adjusting the current imput as the resistance at the gap varies to substantially constantly fuse the metal electrode as presented,

10. In the electrical fusion of metals wherein a metal of desired analysis is produced by fusion of its constituents at a gap through which electric current is discharged between the end of a metal electrode and a conductive body, the steps comprising, feeding at a substantially constant rate to the gap, a hollow metal electrode made up of constituents of the desired metal, discharging electric current through the gap between the end of the metal electrode and the conductive body, the electric current imput to the gap normally being such that the hollow metal electrode is fused at the rate fed when the gap is of a predetermined resistance, varying the electric current imput to the gap inversely as the resistance at the gap varies to substantially constantly fuse the electrode at the rate fed, and supplying at a constant rate through the hollow metal electrode metal in granular form made up of constituents of the desired metal to be fused at the gap with the metal of the hollow metal electrode, the rate of feed of the hollow metal electrode and the rate of supply of the metal in granular form be-- ing such that the constituents of the desired metal are substantially constantly fused at the gap in the proportions required in the desired metal.

ROBERT K, HOPKINS.

f CERTIFICATE ei corun'tgr 'xolw. Patent Ne. 2,500,670. v .ldvenber' 3, l.4.2'. ROBERT K'. HoPKms.

It is hereby certified that error appears in'the printed specification of the above numbered patent requiring correction as followa: Page 5, firet column line 56, for the word "speed" re ad --feed line 51, forinctrea'sea" read -deereaeer-j flageLfirst column, line 23 claim 6; fer'apparatus of the character described? read' --metal ifueing apparatta-q and linea 29, 50and 51., same claim, strike out "said feeding means foehig adapted to feed said electrode at asu batantiallj 'censtant predetermined ratefl} and. lines 57, 58 and 59, cl-aim7, strike out "said means beihgedapted to feed' said hollew electrode at a substantially censtant predetermined rateahd that the said Letters Patent should be readwith this cerrecti on therein that the same may conform to the record of the caeeinthe'Pate'nt of Signed and aefled'thia 12m day of Jan ur a. n)- 1915.

. Henry Van Arsdale, (Seal) Acting Commissioner of Patents} i CERTIFICATE oi coanacmmf- I Patent No. 2,500,670." Rovenb.er' 3, 194.2".

ROBERT K. HOPKINS.

It 1e hereby certified that erroi' appears inthe printed specification of the above numbered. patent requiring correction as follows} Page 5, first column, line 56, for theword "speed" read --feed line 51 forincirea'ses" read --decreas'es--; age'l first column, line 2 claim fop'apparatus of the character described," read "metal fue1ng apparaci1s--; and l'inea 29 50and 51., same claim, atr ike out said feeding means beir'ig 'adapte d to feed said. electrode at a suhetantially 'consfiant predetermined rafiefl'} and lines 57, 5a and 59, cl-aim7,st rike out'aid means beihghdapted to feed] said hollow electi-ode at a substantially compent pn'edeter mined l 'atefi; add that the geld Letters Patent should be readwijzh this correction therein that the same may conform to the record of case .1n.the'Patent Offies; e I k I a v I I Signed and sealeatniel am day of Janaai'y,-A 15: 191;

. Henry Van Arsdale, (Seal) acting Commissioner of Patents