GB471862A - Improvements in and relating to a method of manufacturing hard metal alloys - Google Patents

Abstract

Hard metal alloys consisting of a major portion of a carbide and a balance of auxiliary metal are produced by mixing ore containing the element or elements to be converted into carbide with the auxiliary metal either free or combined in a compound or an ore and heating such mixture in the presence of an amount of carbon sufficient at least to carburize the required amount of the carbide-forming elements, the heating being carried out so as to separate the necessary elements from the ore, carburize the elements required as carbides and alloy the latter with the auxiliary metal. The alloy thus formed is separated from the residue. The ores may contain the elements at least in part in the form of oxides and the carbon may be wholly or partly in the solid state or wholly or partly in the form of a gas or vapour containing carbon preferably at a pressure of above one atmosphere. Sulphur and other impurities may be removed by heat treatment from the ores before the latter are treated with carbon. The amounts of the ores may be proportioned so as to give an alloy containing 65-95 per cent of carbide and the balance auxiliary metal. Ores containing one to four of the following elements of tungsten, molybdenum, tantalum, titanium, silicon, boron, zirconium, niobium, chromium or vanadium may be used, and the binding metal may be selected from the group comprising iron nickel cobalt and chromium. The production of alloys containing 70-75 per cent tungsten carbide and the balance iron from ferberite or wolframite and of alloys containing 75-77 per cent of tungsten carbide and the balance manganese from hybnerite is described.