US2193413A - Process for producing hard metal carbide alloys - Google Patents

Description

March 12, 1940. P WRlGH-i' 2,193,413

PROCESS FOR PRODUCING HARD METAL CARBIDE ALLOYS Filed April 14, 1958 2 Sheets-Sheet 1 March l2, 1940. P WRIGHT 2,193,413

PROCESS FOR PRODUCING HARD METAL CARBIDE ALLOYS Filed April 14, 1938 2 Sheets-Sheet 2 32 34 "1"""\` M Ul` x A TTORN E YS.

Patented Mar. 12, 1940 PATENT OFFICE PROCESS FOR PROIXIUCING HARD METAL CARBIDE ALLOYS Peter Wright, Hillside, N. J., assignor to Carl Eisen and Joseph J. Haesler, both of Montclair,

Application anni 14, 193s, serian No. 202,035

13 Claims.

This invention relates to hard metal carbide alloys useful for cutting tools, tool bits. wearing parts, wire drawing dies, and other uses as well as to a process for making such hard metal carbides. A

Hard metal carbides have been known for a long time and within the past decade have assumed considerable commercial importance particularly in compositions which are'principally n tungsten carbide or in which tungsten carbide is the most important controlling element in so far as either wear or cutting properties are concerned. In the commercial development of these hard metal carbides oi various compositions many processes have been proposed for the preparation of the raw materials, reduction of oxides to metal where necessary, carburizing those metals which form carbides, forming the carbides into proper shapes for cutting tools, wearing parts, tool tips and the like, heating the carbides to sinterng temperatures thereby forming hard alloys, etc. These developments in hard metal carbides have not been confined to those in which tungsten carbide is the predominating property controlling material. A number of suggestions have been made particularly in the patented art of other metallic carbides alleged to have desirable properties for the purpose to which the tungsten carbide alloys have been put. Among these suggestions is that of employing titanium carbide, usually, however, with the inclusion oi other metallic carbides. At the present time there is no commercially produced metal carbide in'which titanium carbide is present in the major proportion of the carbides of the alloy. Some commercial alloys have been prepared for particular purposes in which are included up to about 25% 0; titanium carbide the remainder being principally tungsten carbide. Such commercial products have been found to be extremely br'ttle and are useful only in very limited flelds.

it has been proposed to prepare hard metal carbides comprising titanium carbide by the usual methods as applied to tungsten carbide which includes specifically the pressure forming of the article from the powdered carbide and powdered auxiliary combining or eementing metals and then sintering the formed article. However, these methods, while apparently producing satisfactory hard alloys wherein the tungsten is the predominating hard metal carbide, are not satisfactory to produce titanium carbide alloys.

l have discovered a method for producing hard,

metal carbide alloys that can be used for preparing various metal carbide alloys but is peculiarly adapted for producing a titanium carbide alloy having superior properties to those heretofore attained not only in titanium carbide alloys but also in the various tungsten carbide alloys.

The invention resides in a process for preparing refractory metal carbides which comprises heating a metal carbide and an auxiliary metal to a temperature above the melting point of the auxiliary metal and below the melting point of the metal carbide then gradually applying increasing continuous pressures to the alloy accompanied by vibration independently applied until the temperature has fallen below the melting point of any constituent of the alloy.

in a more specific sense the invention resides in a process for preparing a titanium carbide alloy which comprises heating titanium carbide and auxiliary metals comprising chromium and nickel to a temperature above the melting point of at least one of the auxiliary metals and below the melting point of the titanium carbide then gradually applying increasing pressures to thel alloy accompanied by vibration until the tern-l perature has fallen below the melting point of any constituent of the alloy.

Another specic aspect of the invention resides in a process for preparing hard metal carbide alloys which comprises preparing a composition containing at least fty percent of titanium carbide and from ve to fifty percent of auxiliary metal comprising chromium and nickel, placing the composition in a mold, heating to an alloying temperature above the melting point oi the nickel and below the meltingpoint of the ata- 35 nium carbide while applying a slight pressure to maintain the heated composition in contact with the mold, stopping the application of heat and gradually applying increasing pressures accompanied by vibration until the alloy has been compressed in the ratio of to 125 grams of original mixture to each cubic inch or nnished alloy and the temperature is below the melting point of any constituent of the alloy.

A very specic aspect of the invention is the process for preparing hard metal carbide alloys which comprises heating a mixture of approximately seventy-five percent of titanium carbide with approximately eight percent of chromium and seventeen -percent of nickel under non-oxidizing conditions to a temperature above about 2000" centigrade and until the mixture is alloyed to form a slightly shrunk frlable material, breaking up the said material, placing from 80 to 125 grams of the powdered material ing the material until it is again at the alloying temperature, stopping the application of heat and gradually applying increasing pressures accompanied by vibration until the alloy has been compressed to the predetermined size and the temperature is below the melting point of any constituent of the alloy.

My invention also provides a hard metal carbide alloy comprising a metal carbide of the 4th, 5th or 6th periodic group and an auxiliary metal of a member of the iron group with about one half as much chromium thoroughly alloyed at a temperature below the melting point of the carbide and having its maximum density.

Specifically my invention resides in a titanium carbide alloy comprising approximately seventyve parts of titanium carbide thoroughly alloyed at a temperature below the melting point of the titanium carbide with approximately seventeen parts of nickel and eight parts of chromium, of maximum density and exhibiting a hardness of 9i on the Rockwell scale A useful for cutting tools, dies and wearing surfaces.

'I'he invention will be speciilcally described with reference to certain preferred embodiments thereof andrparticularly as applied to alloys in which titanium carbide is the principal metal carbide constituent but it will be understood that many of the steps of the process are subject to modification in the light of some of the general principals understood in this art and also that certain features of the invention are applicable to tungsten, tantalum or other hard metal carbides, silieides, tellurides or borides of the fourth, nfth and sixth groups of the periodic table or mixtures of them.

To prepare a hard titanium carbide alloy a mixture is made comprising about seventy-five parts of titanium carbide, eight parts oi chromium and seventeen parts of nickel.

The titanium carbide should contain approximately seventeen percent of combined carbon i and be relatively free of graphitic carbon. Preferably, the titanium carbide is ground to a Very ne mesh. This can be obtained by barreling titanium carbide for extended periods of time as is well understood in the art. A f'lneness of at least 330 mesh is preferable. The relative amount of the titanium carbide may be varied from as low as forty percent to as high as ninety- 'eight percent but is preferably within about sixty percent to ninety percent of the original mixture.

The chromium and nickel may be collectively considered as an auxiliary metal or auxiliary metals. Broadly, in place of nickel the other members of the iron group i. e. cobalt or iron,

may be substituted but While cobalt is preferable for tungsten carbide, nickell appears to give superior results with titanium carbide. These metals either alone or in combination when alloyed with the titanium carbide serve as binding metals i. e., they cement the titanium carbide particles together by an alloying action.

Such auxiliary metals may be present in varying amounts but increasing their relative proportion in the mixture while tending to increase the toughness of the alloy also produces a softer or less abrasive product. Varying amounts may be employed from 1 or 2% to as high as 40 to but usually about 15%, not including the chromium is preferable.

'I'he chromium or an equivalent metal serves as the hardening agent in the sense that while per cubic inch of finished alloy in a mold, heat the binding metal produces a tough coherent product the presence of the binding metal has a softening effect The presence of the chromium in the proportion of about half that of the metals of the iron group not only overcomes this softening effect but actually increases the hardness of the alloy produced. For best results the auxiliary metal should comprise at least 1% of chromium or other equivalent hardening metal.

It is usually satisfactory to add the auxiliary metals, the chromium and nickel, as metallic powders preferably finely ground, however, relatively coarse titanium carbide and the coarse powders of the metallic elements may be mixed and then barreled ground in a ball mill together. Instead of mixing the ingredients as carbides and metals, titanium oxide may be mixed with oxides of the other metals which are reduced together and carburized to produce the titanium carbide. As an alternative method, the prepared titanium carbide may be mixed with solutions of chromium and nickel salts which are precipitated `on the titanium carbide and reduced with a gaseous reducing agent as for example, hydrogen. In any of these processes wherein the auxiliary metals are added to the titanium carbide other than as finely ground metallic powders, the mixtures must of course be barreled or ground to insure minute subdivision and thorough'mixing.

After a suitable mixture of titanium carbide with proper proportions and amounts of auxiliary metals in finely divided form have been prepared it is, in the preferred embodiment of the invention, placed in a crucible provided with a nonoxidizing liner. Conveniently the lining of the crucible may be magnesite, alundum, graphite or the like. 'Ihe crucible containing the loose powder is then covered to prevent access of air or subjected to an indifferent atmosphere and heated, conveniently in an electric induction furnace to an alloying temperature preferably about 2000 centigrade which may be described broadly as a temperature above the melting point of at least one of the auxiliary metals but below the melting point of the carbide. The heating, when small amounts of the mixture are in a crucible, should continue for a few minutes after the requisite temperature has been attained, In the case of a crucible containing 200 grams of mixture heated by a 25 KVA induction heater in a crucible surrounded by a layer of graphite a period of less than fifteen minutes after the material had been brought to heat was suilicient.

` 'I'his step as well as other heating steps may if ing or disintegrating treatment to reduce it tok a powder but it has been found preferable to barrel this material to insure extreme neness of the alloy. 'I 'he flner the material is ground the better the properties of the ultimate product, asa general rule.

The pre-allowed titanium carbide and auxiliary metals after being reduced to a powder of the degree of -iineness desired is then placed in a mold, hereinafter more specifically described which is made of graphite. 4Such molds are illustratedper se in Figures l to 4"of the accompanying drawings and positioned lar line 3 3 .of Figure 1 showing the powdered alloy in the mold 'and the plugs partly inserted as at the beginning of a heat;

ligure 4 is a view also in section along the Iline d--ll vof 'Figure l showing the mold, alloy and plugs at the end of a heat; and

Figure 5 is a view principally in elevation of the compression and vibrating apparatus associated with the furnace shown in section. The graphite mold is provided with recesses of the shape of the product to be produced. These shapes will, of course, vary depending upon whether tool tips, tool bits, wearing parts or the like are to be produced. Each of the recesses is also provided with tight tting graphite plugs which have a thickness less than the depth of the recess. The difference in depth .between the recess and the thickness of the plug would be the thickness or" the article to be produced and the dimensions of this space in the recess, which would not be lled when the plug has been forced down to where its top is even with the surface of the mold, is considered the size of the ar ticle. This volume is carefully computed and for each cubic inch of volume there is introduced from 80 to 125 grams of the prealloyed material. Where the composition of the prealloyed material '1s substantially '75 parts of titanium, the preferred ratio is 95 to 100 grams per cubic inch. When the proportion of titanium carbide is increased the number of grams per cubic inch is reduced. For tungsten carbides, of higher density, ratios as high as 225 to 250 grams per cubic inch are recommended depending on the amount of binder. Using the proper weight per volume is usually very important.

After the proper weight of prealloyed material has been put into the mold, the plug or plugs, if more than one article is made in a single mold, is inserted into the recess to lightly compact the material but is not forced down with any substantial pressure. As the powdered prealloyed material has a substantially larger volume than the nished article will have, the plugs project a substantial distance from the surface of the mold.

The graphite mold is then placed in an induction furnace provided with a graphite lining which, along with the mold, is heated by induction. The mold is supported on a substantial base and a graphite post set on the plug on plugs. At the upper end of the graphite post, a body having considerable inertia, as for example a steel bar weighing about 150 pounds, is permitted to exert its weight on the graphite post thereby applying pressure to the ppwdered alloy within the supported mold. This pressure is constant but relatively light, being only suiiicient to follow the creep of this metal'. I

After the mold has been placed in the furnace under the conditions described, the current is turned on to bring the contents of the furnace up to heat. 'I'his temperature is about 2000 centigrade or slightly higher but below the melting point of the carbide. As the material is brought up to heat the pressure exerted `by the steel bar maintains the prealloyed material within the mold in contact with the walls and does not permit it to creep away as it would if no pressure were being applied. The pressure being applied by the steel bar may be considered as one suiiicient to maintain the material in the mold in contact with the walls thereof which in the sense as herein used would include the plug as a wallv of the mold.

When' the temperature has reached approxivmately 2000 centigrade, it is maintained for a short period of time which, in the case of tool bits about 21/2 inches long by inch square in a single mold was about minutes. The current for the induction furnace is cut oi and the pressure on the plugs in the mold or molds gradually increased in a manner that may be described generally as inversely of the falling temperature. At rst thepressure exerted is very slight then as the temperature in the furnace falls, the pressure is increased but at such a rate that the mold itself is not broken. Graphite molds under the high temperature here employed will not withstand excessive pressures.. The pressure is also raised in accordance with the feel of the alloy as transmitted through the handle of the hydraulic jack conveniently used to apply the pressure.

The application of pressure to the steel bar and through it to the heated material in the mold is accompanied by vibration applied either through the mold or more conveniently on the plugs. Proper vibration is attained by sharp impacts on the steel bar. The direction, force, and. position on the steel bar to which the impacts are delivered may be varied widely. For example, light but rapid tapping of one end of the bar with a small hammer has proved sucient. There is no direct application of the impacts to the material in the mold. Obviously the impacts may be delivered by hand while the operator is increasing the pressure or it may be attained by mechanical means. The combination of pressure with vibration under the conditions described produces a hard metal carbide alloy of maximum density for the constituents present. Such a condition insures superior performance of the hard metal carbides when used for the purposes to which they are adapted.

It has been found that pressures actually applied to the alloy are less than 1000 pounds per square inch and usually of the order of 600 pounds per square inch, based on the area of the plugs in contact with the alloy being limited by the strength of the mold. Such pressures are attained before the plugs are driven down into the mold so that their exposed faces are substantially flush with the surface of the mold. After this condition has been attained, the further application of pressure would be across the entire surface of the mold and thereby have a negligible effect in compressing the alloy within the mold.

This pressure and the driving of the plugs to the condition wherein their tops are iush with the surface of the mold is attained substantially at the time when the temperature of the alloy is just above the melting point of any constituent of the alloy but the pressure is maintained until the contents of the furnace have fallen to below the melting point of any constituent of the alloy. Further cooling is usually desirable before removing the mold from the furnace. When the mold is removed from the furnace while still hot 'Ill exclude atmospheric air.

When the mold and its contents have been.

cooled sufficiently, the hard metal carbide alloy is removed from the mold as a finished product its shape corresponding to that of the mold in which it was formed.

The metal carbide alloy produced by this process when the composition comprises 75% titanium carbide with v25% of nickel and chromium in the approximate ratio of two to 'one is a cutting material with a hardness of 91 on the Rockwell Scale A. It has a high tensile strength above that of the commercial tungsten carbide alloys. Its specific gravity isV approximately Yone-half that of the usual tungsten carbide cutting alloy. Because of the method of preparation alloys produced according to this invention have the maximum density obtainable for the constituents present. constituents will affect the actual density but in all cases maximum density is assured. In the processes of the prior art involving pressing before sintering or forging after removal lfrom the furnace it was not possible to insure freedom from pores. One of the important prcrties of this alloy is its high heat resistance as a result of which it can be used in cutting hard steels very rapidly so that the steel comes off as a white hot spiral yet the tool does not break down or crater.

lthough the alloy exhibits extreme hardness and is useful for fast cutting and freedom from fracture or cratering while giving long service, it may be ground readily on a 60 mesh green grit wheel and nished on a 120 mesh green grit wheel. The alloys heretofore used as cutting alloys were particularly subject to the limitation that they could not be satisfactorily ground and that after a tool had become dull it was impossible to regrincl it without so weakening its structure that when reused it readily cracked in many instances.

In the preferred embodiment of the invention two principal steps are employed, viz: prealloying followed by a second heating in a moldincluding pressure and vibration. It has been found that good results are also secured when finely ground carbide and thoroughly mixed auxiliary metal are placed directly in the mold as a loose powder in the manner heretofore described for the second heating in the mold. By this method the alloying is done in the strongly reducing environment of the graphite mold instead of the more desirable neutral crucible. This may be partly overcome by lining the mold. Except that a slightly longer heating may be found preferable before the application of the increasing pressures accompanied by vibration the process of the mold step is substantially the sa-me. Both the one and two step methods as herein defined are a part of the invention.

In the description of the process it was stated that the heating step in the mold was carried out in an induction furnace. An apparatus which I have made up and successfully used with.

my process is illustrated in Figure 5 and comprises a pair of upright members 2 and 4 suitably supported at 6 on the floor or other base and connected near the bottom by angle irons or the like 8 to provide a firm foundation. Spaced above the lower member may be projections I0 on which can be Aplaced an asbestos or other insulating It will be understood that varying the board l2 which'extends between the uprights to support the furnace I4. As such a boardwill not carry any substantial load, a refractory plug I6 is placed on the base members I or on refractory brick I8 and of suilicient height to go through a hole in the central portion of the asbestos board I 2 into the lower part of the furnace coil I4. The coil 22 ofthe induction furnace rests on the asbestos board l2. Near the top of the apparatus the uprights are connected by suitable reenforcing members 24 and 26 conveniently angle` irons. Slidable upon the uprights. a relatively heavy steel bar 28, which may weigh about 150 pounds,is mounted. Means comprising chains attached to a pawl and ratchet mechanism 32, 34 are also provided to raise and lower the steel bar and between the top connecting members and the steel bar is placed a hydraulic jack 35 which, when pressure is applied, will force the connecting member 38 and steel bar 28 downwardly. Within the coil 22 of the induction furnace i4, which may be helical copper tubing 40 through which water may be circulated for cooling, is placed a refractory sleeve 42 of quartz which may have a mica layer 44 on the outside. The refractory sleeve is lined with a composition i6 known as Norblack, er lampblack, within which is a graphite sleeve 38, which is heated when the high frequency current is passed 4through the copper coil by the wires 5U. The inner diameter 4of the graphite is suiciently large to receive either the crucible for the preailoying treatment or the mold and may have a cover 52.

The molds Figures 1 to 4 are made from a re fractory material that retains its strength at the temperatures involved and may be made from graphite rods of a few inches in length and of a diameter which can be received within the lining. One face of the mold El) is drilled, if circular pieces of alloy are to be made, or milled where tool bits are desired. The recesses formed are of the size which the nal product is to have. Where the recesses 82 are formed by milling, su1t able stops or side pieces $4 must also be inserted to close the ends of the slots $2 milled out. Each recess is then closely iitted with a plug Si of such height that when it is forced downwardly within the recess to the vpoint where its upper surface coincides with that of the mold that the dimensions of the uniilled space correspond to those of the finished article. It is usually preferable that the plugs 66 correspond with the larger surface of the article formed. When the molds il have been illled with powdered alloy il ln the manner above described, the plugs will project substantially from the upper surface of the mold (Figure 3) and in this condition are placed witbin the induction furnace I4 preferably resting upon a graphite plug I6 which in turn is supported by the cross members 8 through the refractory brick I8 below the asbestos board above described. The graphite post 54 is rested upon the plugs 66 and projects out of the top of the coil for a short distance where it may be engaged by the steel bar 28 when it has been slightly lowered. The space between the graphite postand the edge of the coil is conveniently closed by an annular refractory disc as for example 52.

When the steel bar 28 has been lowered to rest upon the graphite post 54, the weight of the bar exerts pressure on the plugs Si and maintains this slight pressure upon the material within the mold. This pressure is suilicient to maintain the contents of the mold in contact with the walls thereof.

brought up to the proper temperature by the.

passage of current vthrough the coils, the heat is continued to insure thorough alloying of the constituents. For relatively small pieces a matter of a few minutes as above described, is sudicient.

Pressure is then applied by operation of the hydraulic jack 35 through the medium of a lever attached thereto Vat 3l to force the steel bar downwardly and away from the upper cross member. The operator by reciprocating the ha-ndle of the hydraulic jack gradually increases the pressure upon the plugs and in turn upon the heated alloy i within the mold. The pressure as exerted by the hydraulic jack is applied gradually in a manner which an experienced operator learns to feel and increased slowly but continually until as high a pressure as the mold will withstand has been imposed.

Coincident with the application of the increasing pressures, and in some instances during the application of the slight pressure exerted by the steel bar, the apparatus is subjected to vibration j which is transmitted to the heated alloy. For small operations the vibration is attained by rapidly striking the steel bar with a hammer. The apparatus may comprise mechanical or electrical means @9 for setting up the vibrations. In most instances it has been found preferable to produce the vibration by impact against the steel bar, or other equivalent member having a large mass as compared to the striking object.

The maximum pressure will usually be coincident with the driving of the plug to the point where it is nush with the surface of the mold and as the graphite post d and enlarged portion 55 usually covers several plugs or at any rate is larger than any single plug, any further pressure is exerted over the entire surface of the mold. Gage pressures 35 on a ten ton hydraulic jack have been as high as 6000 pounds where three tool bits, 21/2 by by :A3 inches were made in a single mold before the plugs were driven to the point where they were flush with the surface of the mold.

When the material is prealloyed as in the twostep process above described, the crucible may be put into the same electric furnace i0 in place of the mold but in such cases, of course, the pressure applying apparatus is not necessary nor used.

Alloys prepared according to the process of this invention with the compositions set forth or with small amounts of other metals such as tin, vanadium, zinc, etc., which preferably do not have a suillcient afnty for carbon to form carbides at the expense of the titanium carbide are Very useful industrially for the purposes heretofore recognized. The titanium alloys are particularly useful as or for cutting tools. Their great strength, toughness, freedom from internal strains, and hardness coupled with high heat resistance and freedom from cratering provide tools for fast cutting at high surface speeds. Such advantageous properties are not `at the expense of diculty in keeping the tools in best cutting condition because the alloy may be readily ground as above described. A particular abrasive application of the instant alloys is in grinding wheels. For example, an alloy of about the following analysis, titanium carbide 60%, aluminum 25%, nickel and chromium may be formed as a Wheel with a diamond abrasive surface, or for mounting diamonds generally.

While the invention has been described in great detail as to certain preferred embodiments these are to be considered as illustrative of the invention and not in limitation thereof.

' What is claimed is:

fallen below the melting point of any constituent of the alloy.

2. The process for preparing a titanium carbide alloy which comprises heating titanium car bide and an auxiliary metal to a temperature above the melting point of the auxiliary metal and below the melting point of the titanium carbide then gradually applying increasing pressures to the alloy accompanied by vibration until the temperature has fallen below the melting point of any constituent of the alloy.

3. 'I'he process for preparing a titanium carbide alloy which comprises heating titanium carbide and auxiliary metals comprising chromium and nickel to a temperature above the melting point of at least one oi the auxiliary metals and below the melting pointfof the titanium carbide then gradually applying increasing pressures to the alloy accompanied by vibratien until the temperature has fallen below the melting point of any constituent of the alloy.

4i. The process for preparing hard metal carbide alloys which comprises preparing a composition containing at least fifty percent of titanium carbide and from five to fifty percent of auxiliary metal, placing the composition in a mold, heating to an alioying temperature above the melting point of an auxiliary metal and below the melting point of the titanium carbide while applying a slight pressure to maintain the heated composition in contact with the mold, stopping the application of heat and gradually applying increasing pressures until the alloy has been compressed in the ratio of 80 to 125 grams of original mixture to each cubic inch of nnished alloy and the temperature is below the melting point of any constituent of the alloy.

5. The process for preparing hard metal carbide alloys which comprises preparing a composition containing at least fifty percent of titanium carbide and from five to fifty percent of auxiliary metal comprising chromium and nickel, 'placing the composition in a mold, heating to an alloying temperature above the melting point of the nickel and below the melting point of the titanium carbide while applying a slight pressure to maintain the heated composition in contact with the mold, stopping the application of heat and gradually applying increasing pressures until the alloy has been compressed in the ratio of '80 to 125 grams of original mixture to each cubic inch of nished alloy and the temperature is below the melting point of any constituent of the alloy.

6. The process for preparing hard metal car bide alloys which comprises prepsing a composition containing at least fifty percent of a hard metal carbide and from ve to fty percent of auxiliary metal, placing the composition in a mold, heating to an alioying temperature above the melting point of an auxiliary metal and below the melting point of the metal carbide while applying a slight pressure to maintain the heated composition in contact with the mold.

heating to an alloying temperature above the' melting point of an auxiliary metal and below the melting point of the titanium carbide while applying a slight pressure to maintain the heated composition in contact with the mold, 'stopping the application of heat and gradually applying increasing pressure accompanied by vibration until the alloy has been compressed in the ratio ci @il and 125 grams oi' original mixture to each .cubic inch of :nished alloy and the temperature is below the melting' point of any constituent ci the alloy.

3. The process for preparing hard metal carbide alloys which comprises preparing a composition containing atleast fty percent of titanium carbide and from five to nity percent of auxiliary metal comprising chromium and nickel, placing the composition in a mold, heating to an alloying temperature above the melting point of the nickel and below the melting point of the titanium carbide while applying a slight pressure to main- 'Tcain the heated composition in contact with the mold, stopping the application of heat and gradually applying increasing pressures accompanied by vibration until the alloy has been compressed in the ratio of 80 to 12'5 grams of original mixture to each cubic inch of finished alloy and the temperature is below the melting point of any constituent of the alloy.

9. The process for preparing hard metal carbide alloys which comprises heating a mixture of at least fifty percent of a hard metal carbide with auxiliary alloying metals under non-oxidizing conditions to a temperature above about 2000" centigrade and until the mixture is alloyed to iorm a slightly shrunk friable material, breaking up the said material, placing from 80 to 125 grams of the powdered material per cubic inch of iinished alloy in a mold, heating the material until it is again at the alloying temperature, stopping the application of heat and gradually applying increasing pressures accompanied by vibration until the alloy has been compressed to the pre determined size and the temperature is below the melting point of any constituent of the alloy.

i0. The process for preparing hard metal carbide alloys which comprises heating a mixture of at least nity percent of titanium carbide with auxiliary alloying metals under non-oxidizing conditions to a temperature above about 0 centigrade and until the mixture is alloyed to form a slightly shrunk friable material, breaking up the said material, placing from 80 to 125 grams of the powdered material per cubic inch of finished alloy in a mold, heating the material until it is again at the alloying temperature, stopping the application otheat and gradually applying increasing pressures accompanied by vibration until the alloy has been compressed to the predetermined size and the temperature is below the melting point of any constituent of the alloy.

1l. The process for preparing hard metal carbide alloys which comprises heating a mixture of at least fifty percent of titanium carbide with chromium and nickel under non-oxidizing conditions to a temperature above about 2000 centigrade and until the mixture is alloyed to form a slightly shrunk friable material, breaking up the said material, placing from 80 to 125 grams of the powdered material per cubic inch of iinished alloy in a mold, heating the material until it is again at the alloying temperature, stopping the application of heat and gradually applying increasing pressures accompanied by vibration until the alloy has been compressed to the predetermined size and the temperature is below the melting point of any constituent of the alloy.

i2. The process for preparing hard metal carbide alloys which comprises heating a mixture of approximately seventy-ve percent of titanium carbide with approximately eight percent of chromium and seventeen percent of nickel under nonoxidizing conditions to a temperature above about 2000 centigrade and until the mixture is alloyed to form a slightly shrunk friable material, breakihg up the said material, placing from 80 to 125 grams of the powdered material per cubic inch of finished alloy in a mold, heating the material until it is again at the alloying temperature, stopping the application of heat and gradually applying increasing pressures accompanied by vibration until the alloy has been compressed to the predetermined size and the temperature is below the melting point of any constituent of the alloy.

13. The process for preparing a titanium carbide alloy which comprises heating titanium carbide, a boride and auxiliary metals comprising chromium and nickel to a temperature above the melting point of at least one oi the auxiliary metals and below the melting point of the titanium carbide then gradually applying increasing pressures to the alloy accompanied by vibration until the temperature has fallen below the melting point of any constituent of the alloy.

PETER WRIGHT.

Images