GB691298A - Improvements in welding rods, particularly for hard facing purposes - Google Patents

Abstract

An arc welding electrode composed of a metallic core and a flux-forming coating, has constituents present in such proportion that the welding deposit proper thereto (i.e. a welding deposit unaffected in composition by the metal welded) is a precipitation hardenable alloy of which Fe forms at least 50 per cent, and which comprises Nb and/or Ta 0.1-5 per cent, C 0.2-1.5 per cent and so much W and/or Mo that the aggregate content thereof is not less than 2.5 per cent and exceeds the content of any other alloying ingredient (except Fe) and that the content of W plus twice the content of Mo is not less than 4 per cent and not more than 24 per cent; with or without Cr not more than 6 per cent, Ni and/or Co not more than 20 per cent, Si not more than 1.5 per cent, Mn not more than 2 per cent and V not more than 3 per cent. The alloying ingredients may be contained in the core, in the flux or partly in each and, if in the flux, may be evenly distributed therethrough or form a separate layer. In particular examples (a) an electrode is formed of C .3-.35 per cent, Si 0.5-1 per cent, Mn 1-1.5 per cent, Cr 1.5 per cent, W 8 per cent, Co 2 per cent, Nb and/or Ta 0.5-0.6 per cent, balance Fe (b) a core of carbon steel containing C 0.08 per cent is coated with (i) Fe-Mn 3 per cent, Fe-Cr 10 per cent, Fe-W 2 per cent, Fe-Mo 17 per cent, Fe-Nb 4 per cent, Co 7 per cent, Fe-Si 2 per cent, charcoal 2 per cent, flux 53 per cent or (ii) Fe-Mn 3 per cent, Fe-Cr 6 per cent, Fe-W 22.5 per cent, Fe-Nb 3 per cent, Co 6 per cent, Fe-Si 7 per cent, charcoal 1.5 per cent, flux 51 per cent. The flux may consist of limestone and fluorspar with or without rutile or ilmenite and some of the alloying ingredients may be present in the flux as compounds e.g. columbite. The electrodes may be used for building up edge portions of cutting tools, for hard facing of rock drills and hot working tools or for connecting purposes.