Effect of electron beam surface melting on the structure and wear characteristics of cobalt-based hardfacing and its mo-alloyed version

Abstract

Electron beam surface melting has been applied as a posttreatment to plasma-transferred, arc-deposited Stellite 6 hardfacing and its molybdenum-alloyed version. Molybdenum addition increased the surface-related properties—that is, hardness and wear resistance—via enriching the microstructure with carbides. Application of electron beam surface melting caused a further increment in hardness and wear resistance of the molybdenum-alloyed hardfacing by encouraging hypereutectic solidification to form a network of carbides surrounding the cobalt matrix. However, electron beam surface melting of the unalloyed hardfacing, which favored individual precipitation of fine carbides in the microstructure, decreased the wear resistance in contrast to the hardness.