GB582718A - Improvements in or relating to hard facing alloy - Google Patents

Abstract

Alloys, particularly suitable for hard facing purposes, contain 24 to 45 per cent. of fungsten and/or molybdenum, 1 to 5 per cent. of iron, 2 to 5 per cent. of carbon (present as carbides of tungsten and/or molybdenum and iron) 20 to 25 per cent. of chromium, 0.5 to 5 per cent. of deoxidizing and grain refining elements and the balance cobalt. The deoxidising and grain refining elements are chosen from the elements calcium, silicon, manganese and boron or an alloy of silicon, aluminium and zirconium or ferrous alloys of metals of the fourth, fifth and sixth groups of the periodic table. One particular alloy contains 31 per cent. of tungsten and molybdenum, 2 per cent. of iron, 2.25 per cent. of carbon, present as carbide, 24.5 per cent. of chromium, 2.5 per cent. of deoxidising and grain refining elements, the remainder being cobalt. The alloys may be made by preparing a mixture of tungsten, and iron carbides in powder form, for example, in the proportions of 95 per cent. by weight of tungsten carbide and 5 per cent. by weight of iron carbide, and sintering the mixture to form pellets. The sintered mixture is then added to a melt of chromium and cobalt and fused therewith. The deoxidising and grain refining elements are then added and the alloy is cast.