US1721416A - Hard-metal composition - Google Patents

Description

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sii-riuniti Y i Y m" KARL BGHBTIB, 0I BERLIN-LICHT, GERMANY, .ASBIGNOB I0 G mno conm, A @EPURATION or New roux. mii-armer. ooiirosirroir. in praying. Application sisi 'prii es, 192s, sensi m. 104,618,

, My present' invention relates to metal coui-l positions and more particularly to compositions comprising hard metal curbides. It is one of the objects of my invention to provide e herd metal composition of very greet strength and tenacity which is particularly adaptable for use in connection with weer resisting bodies und cutting tools.

In 'my prior Potent No. 1,549,615 grunted August il, 1925, l huye described o iid claimed e. sintered bord motel composition formed by eddiiig to e powdered tungsten lesser degree of lisidness then the iuetel coimpositioiidescribed-in the potent but u much greater degree of toughness or tenscity. ln the manufacture of tbe new product or mu- 4terbil,- ll beve found it advantageous to curburizeftlie powdered 'iorm of tbe besic motel employed, suoli us tungsten, in tbe presence oi the impor of e hydrocarbon, suoli es methoiie, or tbe like although tbe cerburizetion y muy be eiliected by mixing the tungmen powder with carbon such as soot or sugerof carbon if desired. The resulting' composition, however, diii'ers Vstructurelly from that of the prior patent mainly in tbe umount ot 2 suxiiiery instel employed.

ln making tbe new product, en auxiliary metal is applied to e, powdered herd motel carbide, such` es tungsten carbide for exemple, the auxiliary metal buying esintering temperature below the melting point of the carbide. The carbide is produced by liesting the tungsten powder to approximately 1000* C. in the presence of. e. hydrocarbon vapor, such as methane. i When produced in this manner the carbide is a loosely adherent mass which may be easily broken int/o small pieces by hand witlioutfthe em loyment of auxilio, l mechanical means. he carbon contentbf `the curbide will usually be substuntiall thess=xue-es'"described in the prior from 3 to10% 'zof the carbide patent, t :itis i, Y A und muy tungsten monoendyin Germany Hay 7, 1035.

carbide to hen tbe carbide is prepared iii 1,121,416 "PATENT foi-Fi this manner it is possible to use o, larger volume of the auxiliary metal thou wus employed iii the prior patent, The use ci ed-` ditionol 'auxiliary motel provides u metal composition whicii possesses u high degree of tenacity and lierdiiess although tbe hardness of the present composition is slightly less than that described iii my prior potent. 'lFiie increased teiiecity of the present composb tion, however, together with the bieb degree of hardness which is obteiiied melres it highly desirable igor certain uses es in coii` section with cutting tools und yurious forms of utensils. 4

Zilie ouiriiiziry metals muy comprise, es in ilic moin patent, motels wiiicli lieve e sistern iirg temperature lower tliuii tbe meltingpoint of tbe cu-rbide, ioi' enuuipldiron, comit sindv nickel, und the quantity oit uuiiii iury metal employed muy constitute from l0 to 20% oit the slioy, ultliougli ordinerily it will not exceed 20% it un extremely bigb degree oi' lisrdries is required.. Cutting tools formed of tlie ubore composition ure extremely bord oud tough, und ure copoble oi cutting not only the liurdest lmown steels but also materiels which generally ubrude cutting 'tools The eiiuiliury motel muy be in iiiiely powdered form und should be "pressed into tbe sof pulverizeol bord metal carbide, und' the inold- I ed bod tben lieuted tou sintering tem ereture. he pressure employed dependps ou the shape or tbe iiiiished product und muy very between 20@ und 800 lig. per sq. om. rllie resulting muteriul is insgnetic, und itis my opinion tbut tbe suiiiliery metal sets .to cement tlie particles ot tbe carbide, giving strength und toughness to tlie nislicd urticle. As' described iii my prior patent tlie temperature et which siiiteringV occurs is olif .footed by tbe quantity oit the auxiliary instel l employed but iii eny cese tbe presence of tbe auxiliary metal reduces the siiitering point of the body` for below the fusion fpoiut ot tlie carbide. or exemple, with 5 to 7%'75 cobelt. the final sintering temperature is about 14000 C. With 10% cobalt, the sintering temperature is 13.80 (Maud with 15%co-` halt, the sintering temperature .is 1340? G.

The sintering temperature should be maiii` tained more than one hour,

groferebly an hour `and a half, no ma-tter ow high the iin `cob-alt content of the composition. *If desired, instead of a single auxiliarymet'al a plurality of such metalsmay be employed but the amount of such metals should not` ordinaril exceed of the. entire quantity of the al oy.

I by Letters Patent of the United States isf--y CSI 1."A sintered, hard and tough, metal composition consisting mainly of a hard metal carbide and an auxiliary metal cementing particles of the carbide together, said auX- iliary metal havin a sintering temperature lower than the me ting point of the carbide and comprising more than 10% of the re' sulting combination.

2. Av `ntered, hard and tough, composi- .said auxiliary metal forming more than 10% but not more than 20% of the total content of the composition, saidcomposition having a sintering temperature lower than the melting point of the carbide.

5. A sintered, hard and tough, metal composition consisting largely of a hard metal carbide, and' containing an appreciable amount of cobalt, the cobalt forming more ary What I claim as new and desire to' secureV composition. I 1

6. A sintered cutting tool, said tool le011- sisting mainly of a hard metal carbide, and

containing an appreciable amount of auxilimetal having a sintering temperature lower than the melting point of the carbide, said auxiliaryl metal forming more than 10% of the total content of the cutting tool.

7. A sintered cutting tool consisting largely of a hard metal carbide, and containing an appreciable amount of cobalt, the cobalt forming more than 10% of the total content of the cutting tool.

8. A sintered cutting tool consisting largely of a carbide of tungsten and containing an appreciable amount of a metal having a lower melting point that the carbide, said metal forming more than 10% of the total content of the cutting tool.

9. A sintered, hard and tough, metal composition consisting mainly of tungsten carbide and containing more than 10% of cobalt. i'

10. A. .sintered, hard and tough, metal composition consisting mainly Jot a carbide ot metal of the sixth group and a quantity of metal of the iron group, the metal ofthe iron group forming more than 10% and less than 20% of the composition. i

1l. AV sintered, hard and tough, metal composition consisting largely of tungsten and containing cobalt and carbon, the amount of cobalt being more than 10% and less than 20% of the total content of the metal composition.

KARL SCHRTER.

i than 10% of the total content of the metal