US2119488A - Alloys and process of making same - Google Patents

Description

L, 1 laden -5 1" UNETED' STATES PATENT OFFECE I h I: 2,119,488 1 i I b ALLOYS AND PROCESS or minus SAME Henry N. l'adowicz, Bloomfield, N. 3., assignor to Sirian Wire and Contact Company, Newark. Pi) N. 1., a corporation of Delaware No Drawing. Application July 31, 1936, Serial No. 93,733

K o n I .1- "l 5 15 Claims. (Cl. 75-136) The present invention relates to the production dium. or it may be utilized in the amount of of hard metal alloys, and it particularly relates between 1% and 5%. xii to the production of alloys which may be uti- It has been iound desirable to combine these I s! I lized for making various types of cutting tools, carbides with substantial amounts of cobalt, iron l wear-resisting implements. and so forth. and/or nickel. and this may be done by adding, 5

It has been proposed to make hard metal the finely divided carbide mixture to a solubodies from combinations of tungsten carbide tion, slurry or liquid dispersion of the water and cobalt which are sintercd together at temsoluble. organic cobalt or nickel compound. This peratures between 1500' C. and 1600 C. It has method-of combining nickel and cobalt with the been found. however. that the hard metal alloys carbides is more fully described and setAortlf1m'----.

quite expensive and diflicult to'manuiacture. Julyalst. 1936. e v

nevertheless are not fully satisfactory in their In the-preferred procedure. intzsaid'.

; hardness and wearing I co-pendin: applleatton.-;the pulvedged and; ii1 1ely 1 i It is among the objects of t 5 present inven divided :carblde added to a' "col een- 1s iiou to prepare an improved 'haru 'iiwilioytluird solutionkoiia wbuitgsalkslhelpm;

it ifimiiandzoi1iligii i lyl fii fi t10. cobglirsalt mineproduced according to these processes. although in co-pending.applioatlon serialljlg fiflili. filed cobalt-acetate. In iieu z'cf' strenntli',"hardness and density, which may be opartp gll o 'eicoff tqacetate'it wposslble to r- -wmade of uniform quality from to batch. use other solublcffilts'isucnas cobaltsulphatc. go and which will have a sullicient degree of toughcobalt chloride; or, cobaltnitrate. and preferably bass and density toenable its-wide utilization the cobalt-gsaltjisused in the ionn ota concenin connection with 'w g saturated cutting tools,'and so forth. e and even carry particles of the cobalt Other objects will be obvious and will appear salt or even insoluble cobalteompounds in sus- 9;, during the course of the following specification. pension. I V g.

In accomplishing the objects of the present In lieu of some or all the cobalt-compound invention it has been found most suitable to or compounds above mentioned it is'posslble to prepare a mixture of finely divided carbides of include the corresponding iron or nickel comrel'ractory metals, said mixture preferably iup nd I 39 eluding two or more of the iollowing carbides: The propogflouing 1 t refractory p 3o titanium c tungsten carbide. tantalum of the additional metal such as cobalt. nlekclior carbide. vanadium carbide. thorium carbide. moitem or the who. is p f r h m g lybdenum carbide, uranium carbide, cglumbium the final ef ctory m m m t t t between carbide, and chromiumcarbide, These carbides 50% t of the aJ1oy, or.ln seine instances '2. are a y bes p ep y o t i the finely betwcenaboutasqt to ,sosag r the ailjoyzja ml divided metal in pure condition, the metal being the additional m g 1 tit b ty most preferably prepared by reduction in a hyabout 10% and- 41% I. the* alloy." ins son e drogen atmosphere in anclectric furnace. m :m; 5 m n n These finely divided refractory metals arcprei carbon m' um h wl 4 erably carburized by heating finely ll and -1o%' t s divided carbon, preferably:- otthe t-gpehknowi: instances: l v

as sugar carbon, in a :e u ng'a esp cm In m iffi car an deem: furnace fvmch atmosphere ture a nd solution of thecobalfacetate'the'finely' may desirably include hydrocarbon gases sue divided carbides mixcdwr mined together as acetylene. ethylene, methane. and so forth. m 1,159., thqamwacatc 4 These finely divided carbides are then migced 505mm gg gfi gp z way s s, 1; .1 Ave Ha v v o a ffi'i ffilrlli L33? vfiiffiiii ifli i iilstirring until a dry solidsma'ss is obtained. This w WW m W solid mass m'aythen be ground and subfinal lmr'd metal alloy. b n 13: 9:11? the ng'cfgrrcd prope -liens are bgt veen Jected t0 rcductlon. most desu'ably in an 0 8C a... H P furnace in hydrogen atmosphere. After this if; in 19';- ef iitanimn. vanadium and/or chromium carbide: hetwocn .10 '35 of tungsten reduction OW has been ithe carbific: and et -sen 10% to 25% of tantalum sultant mass may be formed or pressed to decai'b'zde. Where chromium carbide is also insired shapes and then sintered to form the fincludcd, it may replace the titanium or vana lshed article ready for commercial use in cutting tools, drawing dies, wear-resisting parts, and so forth. 0

The following are several typical examples of carblde mixtures which may be prepared for incorporation with the cobalt or nickel salt solu tion, said carbides being preferably produced by reduction or carburizat-ion in a hydrogen atmosphere;

Example 1.-In parts by weight: 5 of titanium carbide, 63 of tungsten carbide, 20 of tantalum carbide, and 2 of vanadium carbide.

Example 2.In parts by weight: 4 of titanium carbide, l of chromium carbide, and 84 of tungsten carbide.

Example 3.--In parts by weight: 2 of chromium carbide, 35 of tungsten carbide, and 53 of tantalum carbide.

Example 4.In parts by weight: 38 of titanium carbide, 4'10 of tungsten carbide, 150 of tantalum carbide, and 15 of vanadium carbide.

Example 5.-In parts by weight: of tungsten carbide and 60 of tantalum carbide. Example 6.-In parts by weight: 3 of chromium carbide, 5 of titanium carbide, 5 of thorium carbide, 10 of molybdenum carbide, 20 of tungsten carbide, and 20 of tantalum carbide.

Example ?.-In parts by weight: 30 of titanium carbide, B of chromium carbide, and 636 of tung sten carbide.

miesnh m rtir .nqnsatatammraw ie 0.2 .29

C. 0 169? C. The metal fifiders may he separately carburized or they may be mixed together before carburization. 'These metal powders after carburization are milled for a couple of days. preferably without balls, to give a finely divided mixture having a fineness exceeding 180 mesh.

According toone desirable process of combination, the milled carbide mixture of Examples 4, 7, or, 8 is sieved through a 180 mesh screen or sieve and then sprinkled into a solution of 370 parts by weight of crystallized cobalt acetate in 1,000 parts by weight of water.

Of course the cobalt may be replaced in part or whole by equivalent quantities of nickel or iron salts. The solution containing the cobalt acetate is then evaporated to dryness with constant stirring and the residue is dried forabout ten hours and then thoroughly pulverized so that it may be bolted through a 180 mesh screen.

This powder is then loaded into nickel boats and reduced in 'a hydrogen atmosphere in an electric furnace according to the following schedule:

Held A hour at 20 volts Held 1% hours at 50 volts Held A hour at volts Held A hour at volts Held 1%; hours at volts pendent upon the size of the pieces. The tubes are then pushed into the cooler and when cold they are withdrawn.

Although the high temperature treatments, namely the carburizing, the reduction, and the sintering, are carried out in reducing atmospheres, it has been found most suitable to carry out the carburizing in a hydrocarbon atmosphere, while the reduction and sintering operations are carried out in a reducing atmosphere, preferably of hydrogen.

The present application is particularly directed to the combination of mixtures of refractory metal carbides with cobalt or nickel, with the cobalt or nickel being in the form of a water soluble organic salt compound. The process of combining a refractory metal carbide witha solution of cobalt acetate or other cobalt or nickel salts is more fully described and claimed in copending application Serial No. 931734, filed July 31st, 1936. It is also possible to combine finely divided refractory metal powder with the metallic carbides before such metallic carbides are combined with the cobalt acetate solution.

Processes in which the tungsten or other refractory metal is combined in finely divided form with the cobalt or nickel salt, are more fully described and claimed in co-pending application Serial No. 93,171, filed July 29, 1936.

Many other changes could be effected in the particular features of process treatment 'disclosed, and in specific details thereof, without substantially departing from the invention intended to be defined in the claims, the specific description herein merely serving to illustrate certain elements by which, in one embodiment, the

bining this mixture with a water solution of an organic salt of an additional metal selected from the group consisting, of iron, nickel and cobalt, said water solution being concentrated and being evaporated down to dryness while continually stirring, the dry material being pulverized" and sifted and then reduced in a reducing atmosphere. i v

2. A process of preparing refractory metal al-' loys which comprises combining a mixture of finely divided carbides of refractory metals with a water solution of an organicacid salt of cobalt, said water solution being. concentrated and'being evaporated down to dryness. while continuallystirring, the dry material being pulverized and sifted and then reduced in..a reducing atmosphere.

3. A process of preparing hard metal alloys" which comprises combining a mixture of tungsten and tantalum carbides with a water solution of an organic acid salt of cobalt, said water solution being concentrated and being evaporated down to dryness while continually stirring, the dry material being pulverized and sifted and then reduced in a reducing atmosphere. i. A process of preparing hard metal alloys which comprises combining a mixture. of tung sten and tantalum carbides with a water solution of an organic acid salt of nickel, said water solution being concentrated and being evaporated down to dryness wniie continually stirring, the dry material being pulverized and sifted and then reduced in a reducing atmosphere.

5. A process of preparing hard metal alloys which comprises carburizing a mixture of at least two refractory metals, and then combining the mixture with a water solution of an organic acid salt of cobalt, said water solution being concentrated and being evaporated down to dryness while continually stirring, the dry material being pulverized and sifted and then reduced in a reducing atmosphere;

6. A process of preparing hard metal alloys which comprises carburizing tungsten and tantalum with sugar carbon, milling the carbides, sifting the carbides through a 180 mesh screen, and combining the carbides with a water solution of an organic acid salt of cobalt, said water solutlon being concentrated and being evaporated down to dryness while continually stirring, the dry material being pulverized and sifted and then reduced in a reducing atmosphere.

7. A process of preparing hard metal alloys which comprises milling together carbides of tungsten and tantalum, sifting the carbides through a 180 mesh screen, and combining the carbides with cobalt, said combination being ef fected by sprinkling the sifted carbides into a concentrated solution of cobalt acetate, evaporating to dryness with agitation, reducing the dried mixture and sintering.

8. A method of making hard metal alloys which comprises combining together at least two finely divided refractory metal carbides selected from the group consisting of titanium, tantalum, tungsten, chromium, uranium, molybdenum, thorium and vanadium, and combining said carbides with a Water solution of an organic acid salt of cobalt, said water solution being concentrated and being evaporated down to dryness while continually stirring, the dry material being pulverized and sifted and then reduced in a reducing atmosphere.

9. A method of making hard metal alloys which comprises combining together at least two finely divided refractory metal carbides selected from the group consisting of titanium, tantalum, tungsten, chromium, uranium, molybdenum, thorium, vanadium, and sprinkling said carbides into a concentrated cobalt acetate solution, evaporating said solution to dryness with agitation, powdering, reducing the powder in a hydrogen atmosphere, forming the reduced powder, and sintering.

10. A process of producing refractory metal alloys which comprises combining together finely divided refractory metal carbides and the finely divided refractory metals, and then combining this mixture with a water solution of an organic acid salt of cobalt, said water solution being concentrated and being evaporated down to dryness while continually stirring, the dry material being pulverized and sifted and then reduced in a reducing atmosphere.

11. A hard metal alloycomprising about of a mixture of tantalum and tungsten carbides, and about 10% of a mixture of nickel and cobalt, the particles of the carbide being each encased in and cemented together by a coating of nickel and cobalt, said alloy being prepared by mixing the carbides with a salt solution of the encasing metal, followed by evaporating, drying, pulverizing, reducing, compressing and sintering.

12. A hard metal alloy comprising about 90% of a mixture of tantalum and tungsten carbides, and about 10% of cobalt, the carbide particles being each encased in and cemented together by a cobalt coating, said alloy being prepared by mixing the carbides with a salt solution of the encasing metal followed by evaporating, drying, pulverizing, reducing, compressing and sintering.

13, A process of ,producing a hard metal alloy which comprises evaporating a slurry containing and reducing the resultant mixture of finely divided cobalt acetate, tungsten carbide and tantalum carbide, forming, and sintering, the carbide particles being each encased by cobalt acetate before reduction.

14. A hard metal alloy consisting of finely divided tungsten and tantalum carbides, the particles of which are each encased in, and cemented together by, a coating of an additional metal selected from the group consisting of iron, cobalt and nickel, said alloy being prepared by mixing the finely divided tungsten and tantalunncare bides with a solution of a water soluble salt of the additional metal to form a slurry followed by reduction to dryness with constant agitation, reduction of the dried mixture in hydrogen and sintering.

15. A hard metal alloy consisting of finely divided tungsten and tantalum carbides, the particles of which are each encased in. and cemented together by, a coating of an additional metal selected from the group consisting of iron, cobalt and nickel, said alloy being prepared by mixing the finely divided tungsten and tantalum carbides with a solution of a water soluble salt of the additional metal to form a slurry followed by reduction to dryness with constant agitation, reduction of the dried mixture in hydrogen and sintering, said tungsten carbide being utilized in greater proportion than the tantalum carbide.

HENRY N. PADOWICZ.