GB573598A - Improvements in or relating to electrodes or welding rods and to the production of shaped articles therefrom - Google Patents

Abstract

573,598. Making coherent masses from powders. CLARKE, E. J., and MUREX WELDING PROCESSES, Ltd. Nov. 13, 1942, No. 16042. [Class 82 (ii)] [Also in Group XXII] A welding rod consists wholly or in part of a sintered mass containing one or more hard metal carbides and fluxing and/or slag-forming ingredients distributed uniformly throughout the mass. Such a rod may be used for welding on to a mild steel base a facing of extreme hardness. Tungsten carbide may be used with or without titanium carbide or chromium carbide, together with a small proportion of a finely-divided ferrous metal. The powders may be mixed with a binding agent such as a thermoplastic or thermohardening synthetic resin as described in Specification 573,338, and extruded into rod form with a preliminary sintering to drive off the binding agent and consolidate the powders before cutting into lengths and subjecting to final sintering. The fluxing ingredients may include limestone, magnesite, fluorspar, cryolite and a metallic deoxidizer such as ferro-silicon. Powdered iron up to 20 per cent may be included or a small gauge iron wire core for the sintered mass may be used. One rod may be formed by dry pressing and then sintering at 1300‹ to 1400‹ C. a mixture of 90 per cent of tungsten carbide, 5 per cent of titanium carbide and 5 per cent of cobalt in powder form mixed with 4 per cent of a flux consisting of 60 per cent of fluorspar and 40 per cent of calcium carbonate. Another rod may be made by mixing in a ball mill 78 per cent of tungsten carbide, 11 per cent of titanium carbide and 11 per cent of cobalt in powdered form, together with 4 per cent .of a mixture of 60 per cent fluorspar and 40 per cent calcium carbonate, then making into a paste with sodium silicate solution and extruding into rods at a pressure of 5-15 tons per sq. in. and sintering at 1300‹ to 1400‹ C. A further rod is similarly made from 32 per cent of tungsten carbide, 10 per cent of ferro-chrome, 2 per cent of ferro-vanadium, 45 per cent of iron, 4 pet cent of cobalt, 3 per cent of carbon, 3 per cent of cryolite and 1 per cent of magnesite, the sintering temperature being 1250‹ to 1400‹ C. According to the Provisional Specification, a proportion of copper may be included in the mixture to increase the electrical conductivity. Specification 573,595 also is referred to.