THE EFFECTS OF DILUTION UPON THE CORROSION AND WEAR PROPERTIES OF COBALT-BASED WELD OVERLAYS

The use of weld overlays to protect critical surfaces from corrosion a nd wear is well established. In applying such deposits, however, inter mixing with the substrate (dilution) is inevitable. Although it is gen erally accepted that dilution degrades the performance of the overlay, quantitative information is scarce. The purpose of this study was to generate such information. To overcome the issues of compositional hom ogeneity and one-sided corrosion tests, the overlay material (UNS R312 33, a cobalt-based alloy) was premixed with quantities of UNS G10400 c arbon steel and UNS S31603 stainless steel. and standard corrosion and wear samples prepared from all-weld-metal blocks. Significant changes in corrosion and wear behaviour were recorded.