US972630A

US972630A - Process of making compound metal bodies.

Info

Publication number: US972630A
Application number: US55948310A
Authority: US
Inventors: John F Monnot
Original assignee: DUPLEX METALS Co
Current assignee: DUPLEX METALS Co
Priority date: 1910-05-05
Filing date: 1910-05-05
Publication date: 1910-10-11
Anticipated expiration: 1927-10-11

Description

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2 SHEETS-SHEET 1.

ATTORN EY WlTNESSES:

J. F. MONNOT.

PROCESS 0I' MAKING GOMPOUND METAL BODIES.

Arrnxonron Hmm 113.10, 1907. BENBWED un 5, 1910.

72,630, Patented 001;. 11,1910.

2 SHEETS-SHEET 2*.

v INVENTOR Mmw ATTORNEYS UNTTED sTATEs PATENT oEEIoE. j.

JOHN F. MONNOT, OF NEW YORK, N. Y., ASSIGNOB TO DUPLEX METALS COMPANY, OF

NEW YORK, N. Y., A CORPORATION OF NEW YORK.

PROCESS OF MAKING COMPOUND METAL BODIES.

Bpeoioation o! Letters Patent.

Patented oct. 11, 1910.

Application led February 18, 1907, Serial No. 358,007. Renewed Hay 5, 1910. Serial No. 559,483.

To all whom it may concern:

Be it known that I, JOHN F. MoNNoT, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Process of Making Compound Metal Bodies; and I do hereby declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to processes of makingcompound metal bodies and consists in a'method of firmly and permanently welding together unlike metals to form compound metal articles, such unlike metals comprising on the one hand steel and ferrous metals, and similar iron-like metals such as cobalt, nickel and the like, and on the other hand the high melting non-ferrous malleable and ductile metals like copper, silver, gold, aluminum, platinum and the like; all as more fully hereinafter set forth and as claimed.

It is a matter of common knowledge that it is practically impossible to weld together ferrous metals of the class which have a pronounced aiiinity for carbon (for example, form carbids readily) with the unlike nonferrous metals of high melting ,point of the copper and noble metal groups of metals having little or no affinity for carbon (for example, do not form carbidsreadily). For many purposes, however, ferrous metal bases coated with these relatively expensive, relatively inoxidizable metals are desirable and many attempts have been made in the prior art to produce them. It is uite a common expedient. to attempt to ma e a unionl between these unlike metals by simply casting them together at the ordinary casting tem! perature of the non-ferrous metals, but such attempts have not been crowned with practical success, by reason of the lack of atlinity existing between such ferrous metals and such non-ferrous metals at the ordinary cast- -ing temperature of the latter. Quasi-unions have frequently been produced in which the two unlike metals were, so to speak, merely stuck together, but not a union of the nature of a weld; a coherence as distinguished from an adherence. Such compound metal bodies therefore have always permitted ready separation of the .joined metals by mechanical force, temperature changes and the like. A

cold chisel or similar cuttin finds and follows the line o junction, nor will' such articles withstand heating and quenching` in water. Co-extension yof the joined metals by rolling, wire-drawing, hammering and the like have been frequently practiced to a certain degree; to an extentwherein the coating non-ferrous metal has still sufficient thickness to give it mechanical strength enough to support itself.

tool readily In other words, taking copper on steel, a Y

compound ingot made by the rior simple casting process would frequent y ermit of co-extension to a certain extent, t e copper forming, so to speak, a tubular shell around the steel core. When the extension, however, went beyond this point and the copper became a mere film, of insufficient thickness and strength for its own sup ort, it readily stripped from the wire. T is defect has precluded the manufacture of relatively thin film-like coatings upon steel objects to form finished coated articlesby relatively cheap large-scale processes and for such coated articles it is now the usual practice to coat each finished article separately by electrolytic or like process. Electrolytic coatings, however, when thin, readily exfoliate and at any thickness are orous, permitting ready permeation of ampness, gases -or other corroding agencies to the underlying metal.

It is the purpose of the present invention to provide a simple cheap and ready method of forming dense, hard impermeable weldedon coatings of the less oxidizable metals upon the described ferrous and similar metals.

. In other applications Sr. Nos. 281,680 and 333,570, I have described and claimed broadly, methods of forming welded-on coatings of the character described depending on the fact that the lack of affinity between ferrous and non-ferrous met-als at the ordinary casting temperature of the latter, dis.- appears when said non-ferrous metals are raised to a degree relatively high above their melting points, a temperature which I have called, for lack of other name, the supermolten condition. The stated non-ferrous metals when in the supermolten condition readily wet and combine with cleaned surface of ferrous metals, producing a firm, permanent and indestructible union between the two metals, and when the liquid metal the contact of the supermolten co solidies forinin a weld union which resists destruction or iscovery by cutting tools, which cannot be broken by violent temperature changes and which does not rupture along the line of 'unction uon. repeated ilexure of the join, metals t is, aswill be seen, a union similar in all characteristics to that roduoed-by a good weld between pieces ofp ferrous metals, and I therefore call 1t a weld union without necessarilycommitting myself to any theory as to its exact chemical or physical. nature. It may be tlfiatr, or instance, produces a .tenuous lme alloy iilm of copper and steel u n the steel surface; it may be thatthe thinly uld copper, which is so fluid at the supermolten temperature that it readily finds otherwise undiscoverable fissures and aws in the steel, flows molecularly into the intra-molecular lacunae on the surface of the steel, producing, so to s ak, a molecular interlocln'ng such as proba ly occurs in ordinary welding; and many other plausible explanations are possible.

But I content myself with notingthe factl of the existence of the strong permanent union described without committing myself as to theories of its nat-ure. i A

I have now discovered that ,a union-of similar character may b'e produced in a'differentway. If a mass of co per or non.- ferrous `metal of the kind escribed, be placed in an ingot mold of suitable shape, and a clean steel billet heated to what is called a dripping temperature (i. e.- the extreme White heat at which particles rom the surface of the metal begin to drip dowii,)

be contacted therewith, a similar union results, probabl becausetli'e intensely' heated steel raises t e tem erature of proximate layers of copper or tlie like to the necessary supermolten degree. It is of course necessary in this operation that the bulk of the coating metal, which is ordinarily of high heat conductive capacity, be not so great as to cool down the steel at the line or surface of union before the union can take place. However, the amount of coating metal (cop er, for instance) required to roduce coatings of the thickness ordinarl y desired, is-

not sufficient, when confined ina suitable ingot mold, to diminish 'the' temperature of the metals below the uniting point.

It is best to first clean preliminarily--the core or billet to be coated (usually a bar orv block of steel) which may be done advantageously by means of a sandblast or like mechanical means, followed, if desired, by pickling. The core or billet so prepared is then heated to the described temperature under circumstances precluding ox1dation, and when so heated is transferred to the mold containing the coating metal, und'er circumstances precluding oxidation. But the preliminary cleaning isnot necessary inall surface once clean 'cannot become contami- -electrolytically, the stated acids bein :Haase cases because owing to the high temperature to which the hina or core is heated the outer layer will be, or may be, melted off, thus carrying awa. the usual layer of scale or oxid on the sur ace of iron and steel, and exposing a clean metallic surface; and since theheating and transfer of the core to the coating metal are both conducted under circumstances precluding oxidation or other contamination, as hereafter described, the

nated a in. The low -heat conductivity of steel a ows the surface to be raised to or nearly to a melting temperature before the interior becomes dangerously soft. With the surface at a dripping heat any scale or oxid which may be present drips olf leaving a clean metallic surface and when this clean, dripping billet is raised into an atmosphere of producer gas, as it preferably is, it cannot become 're-oxidized as its superficial temerature lowers, the producer gas indeed reucing anyoxid which may form. When pickling is resorted to, as it may be at times nevertheless, it is best performed with an acid 'ving an`iron compound readily volatiliza le such as hydrochloric or h drofluoric acid. Pickling may ofcourse done enerated on the core or billet to be oleane sed as an anode in an electrolyte of a suitable salt solution. The highly heated core or billet havin been transferred to the ingot mold containing the molten coating metal, is immersed in the molten metal and iscarefully centered or otherwise located. in its predetermined position in the mold, and the molten metal is allowed to solidify thereon. The conditions under which the operation is carried on are 105 su'ch that, knowing as I do that the coating metal is capable of reaching the so-'calledsupermolten condition at a temperature. lower than that of the core or billet when immersed in the molten metal, it is reasonable previously heated to such supermolten tem- 120 ,perature, as described in my aforementioned applications.

While I am not limited to the use of any particular apparatus for carrying out my saidvprocesam the accompanying drawings I have illustrated certain apparatus suitable and'convcnient for the purpose.

In said drawings: Figure 1 shows diagrammatically in sectional elevation a heating -furnace `for the cores or billets, with ,130

v lets from oxidation or other contamination while in transit and while being immersed in the coating metal. Fig. 2 shows a detail elevation and partial vertical section of one form of such hoisting, conveying andprote'cting apparatus. Fig. 3 shows a vertical section of the complete ingot mold with a core therein.` Fig. 4 shows a detail elevation and partial section of an alternative form of hoisting and protecting apparatus; Fig. 5 a detail vertical section, on a larger scale, of the gripping mechanism thereof and of the protective casing, and Fig. 6 shows a detail transverse horizontal section through the lower part of such casing, indicating means for centering and guiding the upper end of the billet.

In said drawings, 1 indicates a suitable heating furnace and 2, 2 indicate cores or billets being heated therein. Said furnace has in its roof openings 3 normally closed by two-part covers 4. Each such billet has screwed into its upper end a short porter bar `5 provided with a guide and centering disk 6; and as indicated particularly in Fig. 2, each such disk is tapped from its upper side to permit a second and longer porter bar 7, forming part of the hoisting and conveying apparatus, to be screwed therein. ter bar 7 is weighted, for a reason hereinafter disclosed, and is suspended by means of a cable 8 from a suitable power hoist 9 mounted upon a wheeled truck 10 arranged to move upon a track 11. Surrounding this bar 7 is a casing 12 suspended by cables 13 from a hoist 14 mounted upon the same truck 10. This casing is open at the bot-tom, is adapted to receive through its bottom opening, and to contain, the billets 2, and is provided with means, such as a pipe 15 and valve 16, for supplying to it a non-oxidizing or indifferent atmosphere, such as producer gas made from charcoal and containing no marsh gas or other decomposable hydrocarbons.

The inolten coating 4 metal is contained within an ingot mold 17, such for example as shown in Fig. 3, adapted to receive the lower end of the casing 12, which latter then forms practically a continuation of the ingot mold.

In the construction shown in Fig. 3, said ingot mold consists of a base 18 and cylindrical upper portion 19 of the saine internal diameter as the casing 12, and a collar 20 adapted to receive the lower end of said cas- 'ing 12 and make a tight joint therewith.

Said por? When one of the billets 2 has been heated in the furnace 1 to a suitable temperature, the hoisting and conveying'a parat-us is moved over it, the porter bar 7 Eiwered and screwed into the guide-disk 6, and then the casing 12, filled with the protective atmosphere as aforesaid, is lowered down to the two-partk cover 4, thesections of said cover separated sufi'iciently to permit the billet to be raised, and then sald billet is raised quickly into the casing 12, after which the sections of the cover 4 are re laced, the casing 12 is raised with the billet within it, and the whole conveying apparatus with the billet within the casing 12 1s moved over the in ot mold 17, which has previously been fil ed with a quantity of molten coating metal, at suitable temperature, just suiiicient to form the desired coating. In the case of copper or othei` coating metal which when molten is readily oxidizable, the molten metal is poled or treated with charcoal or a silicon compound to remove any trace of oxid, and its surface is then preferably covered with ux to exclude air.

The casing 12, with the ingot or billet 2 lwithin it, having been brought directly over said in ot mold 17, said ingot mold and billet are owe/red together until the lower end of said casing lits within collar 20 and makes a tight joint with the ingot mold, forming, in tact', an upward continuation thereof. The billet 2 is then lowered to the bottom of the ingot mold, the molten metal rising as it is displaced, and filling the casing 12 to the top of the billet or other desired level; the vent 21, if provided, being closed as this is done. The lower portion of the ingot mold is provided with suitable means for centering the-lower end of the billet-for example, is made conical or tapering. The casin 12 is centered with respect to the ingot mold by the collar 20, andthe upper end of the billet is centered within the casing 12 by the disk 6. Accurate centering of the billet with reference to the coating to be formed is thereby insured. That the eXtreme lower end of the coated billet will be tapering, owing to the taper of the lower portion of the mold interior is unimportant, as in the rolling to which the ingot is subsequently'subjected the coating will be spread so as to give equal thickness of coating throughout.

The molten metal having solidified around the ingot or billet so introduced into it, the coated ingot is forced out of the casing 12, and the latter is ready for use again; the operation having meanwhile been repeated numerous times with other casings and other ingot molds,-the hoists 9 and 14 being readily detachable from the casings 12v and porter bars 7, as shown.

The function of weight 22 on porter bar 7 is to force the billet down into the molten coating metal in case, as may often happen,

i the metal of the billet is of less specific gravity than the molten coatin metal. The casings 12 have weighted hea s 23 for the same reason.

In Fi 4, 5 and '6 I illustrate alternative means or raising and lowering the ingot orbillet to be coated, whereby tap in of the said billet at the to to receive t e s ort porter bar 5 is avoid In this construction, 24 having gripping jaws 25 ada ted to grip and hold the billets 2. This cliuck is suppassing through packed orifices in the head of the casing, (thou h packing around these rods is not strict y necessary, as some leakage of the protective atmosphere around these rods is not objectionab e) and at the top are connected to a slide 26 mounted in guides 27 in the truck 10 and provided with means for raising and lowering it-for example, a rack-bar 28 engaging a pinion 29 on the shaft of a hoisting motor 30. The slide 26 is rovided with a cylinder 31 and piston 32, t e piston rod 33 of which projects through the head ofcasin ported by rods 25'- 12 and is provided with a collar beneathv an Vslapping adapted to engage and o erate the bell-crank aws 25. Va ves 34 and 35 are provided or admitting iuid under pressure above and below the piston 32 at will, and for permittin exhaust, as is common in pneumatic an hydraulic and like Huid-pressure hoists. So long as piston 32 pulls upward, it keeps the jaws 25 in gripping contact with the billet, and prevents slipping of the latter from said jaws. If the pressure below the piston 32 be relieved, said jaws are no longer held closed, and the weight of the bil et will cause them to. release said billet; s rings 36 being provided,

if desired, to faci itate or hasten release of billet.' Iressure above piston 32 will cause the rod 33 to engage the top o f the billet and force the same out of the jaws 25, if necessary, or force the billet down into the molten metal in the ingot mold. In this construction, the casing is best formed of relatively separable sections, 3 7 and 38, as shown, normally held together by convenient latches 39, and the upper end of each section 38 is provided with centering lugs 40, as shown in Fig. 6; the intention being that when the billet is pushed clear down to the bottom of the ingot mold and the molten .metal has risen around it, said molten metal will come just to the topv of the billet and to said centering lugs 40, and just below the joint between the upper and

lower sections

37 and 38 of casing 12.

It will be obvious that the process and apparatus herein described are applicable to the coating of billets or cores of any desired .cross-section, whether round, square,

` elongated in one direction (rectan lar, for

example) or irregular shape; an likewise I provide within the casing a chuck lconvenient means to non-ferrous metals desi that the ingot mold may be of any desired Y cross-section. This process and apparatus are therefore particu arly suitable for producing coated slabs, plates, etc. The coating metal-` not being heated to the su rmolten temperature prior to the introse tion of the articlel to be coated therein, is not so subject to oxidation, contamination or deterioration as is su rmolten metal, and is not so likely to absor or dissolve and become contamlnated with the metal of the core or base coated; a matter of such moment when electrical conductors, for exam' ple, are to be produced. v

The various coating metals which I particularly contemplate using,l for exam le, copper, silver, go d, aluminum, copper allldys such as brass, bronze aluminum bronze, etc.,

are all high melting ductile metals which can be worked with steel at steel working temllc- Y peratures and all have Amelting temperatures above 500 C.; and it is deslrable in most cases `that the coating metal shall be one having a melting temperature above 900 F., since steel reuires to be heated above such temperature or forging and hot-working generally. Hence such temperature forms a distinguish such metals as I particularly contemplate using from metals of low melting point such as lead and tin which cannot be worked with steel at steel working temperatures. I have used the term ferrous metal to designate pure iron, iron (such as may be ma e, for example, by the Tropenas rocess), wrought iron, steel of various gra es, including Various compound steels, such as nickel steel, chrome steel, titanium steel, etc. The term ates the unlike metals, such as copper, si ver, gold, platinum, aluminum, etc., to be used preferably as coating metals. The supermolten temperature of copper, as nearly as I have been able to determine it, is around and above 2500 F.; that of silver is in the same neighborhood; that of gold somewhat higher, and that of aluminum somewhat lower. The dripping temperature of iron or steel varies somewhat carbon in the steel and other well-known conditions, but is in every case, so far as I according to the amount ofI am aware, much above these supermolten temperatures.

.1. The herein described process 'of welduniting unlike metals, which comprises heating a body of one such metal to a high white heat far above the melting temperature of the other metal under circumstances ygiving a clean'metallic surface to said body, -immersing said body so heated in a molten mass of the other such-metal and causing such molten mass to solidify thereon.

2, The herein described process of welduniting unlike metals, which comprises heat'- comprises heating a body of ferrous meta-l ,i

ing a body of one such metal' to a temperature above the supermolten temperature of the other metal under circumstances giving a clean metallic surface to said body, immersing said body so heated in a molten mass of the other such metal and causing such molten mass to solidify thereon.

3. 4The herein described process of Welduniting ferrous metals and non-ferrous metals having melting temperatures above 900 F., which comprises heating a body of ferrous metal to a high White heat far above the melting temperature of such non-ferrous metal under circumstances giving a clean metallic surface to said body, immersing said body so heated in a molten mass of such non-ferrous met-al and causing such molten mass to solidify thereon.

4. The herein described process of welduniting ferrous metals and non-ferrous metals having melting temperatures above 900 F., Which comprises heating a'body of ferrous metal to a temperature above the supermolten temperature of such non-ferrous metal under circumstances giving a clean metallic surface to said body, immersing said body so heated in a molten mass of such non-ferrous metal and causing such molten mass to solidify thereon.

5. The herein described process of Welduniting ferrous metals and cupriferous metals having melting temperatures above 900 F., which comprises heating a body of ferrous metal to a temperature above the supermolten temperature of such cuprifer-V ous metal under circumstances giving a clean metallic surface to said body, immersing said body so heated in a molten mass of such cupriferous metal and causing such molten mass to solidify thereon.

6. The herein described process of weldunitin ferrous metals and copper, which .in the presence of two witnesses.

to a temperature above the supermolten temperature of=`copper under circumstances givlng a clean meta lic surface to said body,

immersing saidbody so heated in a molten mass of copper and causing such molten mass to solidify thereon.

7. The herein described process of Welduniting ferrous, metals and non-ferrous j metals having melting temperatures above 900 F., which comprises heating a body of ferrous metal to a high White heat under circumstances giving a clean metallic surface to said body, immersing said body so heatedin a molten mass of such non-.ferrous l metal and causing such molten mass to 4the melting temperature of the non-ferrous metal under conditions precluding oxidation, transferring said body of ferrous metal so heated, While surrounded with a protective atmosphere, toa molten Vmass of such non-ferrous metal, and'then immersing said body so heated in such vmolten mass and causing such mass to solidi thereon.

In testimony whereof I a my signature,

JOHN F. MONNOT. Witnesses:

JAS. K. CLARK,