The chemistry and structure of wear-resistant, iron-base hardfacing alloys

Abstract

The chemistry and microstructure of iron-base alloys resistant to galling wear were determined by using optical microscopy and scanning electron microscopy (SEM). Castings and weld overlays, deposited by the gas tungsten arc and plasma arc welding (GTAW and PAW, respectively) processes, were evaluated. The microstructure typically consisted of a primary austenitic matrix, eutectic carbides (M7C3 type), and noneutectic carbides. Processing techniques that resulted in high cooling rates yielded microstructures with finer features, less complete partitioning of alloying elements to the carbides, and improved resistance to galling wear. Carbon and manganese appeared to improve resistance to galling wear. Nickel was detrimental to galling wear resistance.