GB802802A - Improvements in sintered carbide compositions - Google Patents

Abstract

A cemented multi-carbide composition consists of 58 to 90 per cent by weight of WC crystals ranging in size from 25 to 250 microns, a major portion being from 25 to 150 microns, and 5 to 32.5 per cent by weight of at least one of the carbides of Ti, Ta, Zr, Nb, sintered into an integral mass with 1.5 to 10 per cent by weight of the sintered product of a binder selected from Co, Ni, Fe or their mixtures. The WC crystals are much larger than normally used but the other carbides have normal grain size i.e. in the range 0.5 to 10 microns; whilst Co is the preferred binder. The method of manufacture is conventional save that the fine grain carbides and binder metal are first ball milled together with a little WC if desired; most of the WC is however then added and the mixture ball milled for a relatively short time to avoid excessive attrition of the coarse WC crystals. The product is useful for cutting and machine tools of various kinds. Examples show compositions of (a) WC 74.3 per cent, TiC 21.4 per cent, Co 4.3 per cent; (b) WC 64.3 per cent, TiC 18.3 per cent, TaC 13.3 per cent, Co 4.1 per cent: (c) WC 65.4 per cent, TiC 27.6 per cent, Co and Ni 3.5 per cent each: (d) WC 63 per cent, TiC 18 per cent, TaC 12.9 per cent, Co 6.1 per cent: (e) WC 61.5 per cent, TiC 17.6 per cent, TaC 12.7 per cent, Co 8.2 per cent: (f) WC 68.1 per cent, TiC 14 per cent, TaC 10.1 per cent, Co. 7.8 per cent: (g) WC 59.1 per cent, TiC 18.8 per cent, TaC 13.7 per cent, Co 8.4 per cent. Specification 802,801 is referred to.