Sliding wear behavior of electron beam surface-melted 0–2 tool steel

Abstract

Studies were carried out on the dry sliding wear behavior of electron beam melted surface layers on a type 0–2 tool steel and on annealed and conventionally hardened 0–2 steel specimens for comparison. Wear tests were conducted in a flowing argon atmosphere at a sliding speed of 20 cm s −1 and a load of 10 N against a 52100 bearing steel ring. Wear surface morphology was studied along with subsurface structure using optical and electron microscopy methods. The study concentrated on the wear of this steel after different processing treatments. Electron beam surface melting and subsequent rapid solidification in situ of the steel produced a highly refined martensitic microstructure having higher hardness values and better wear resistance than obtained using conventional quench hardening of that steel. Carbide distribution and martensite phase morphology were affected by this surface melting process; those microstructural characteristics influenced the wear behavior. Variations in electron beam power and surface speed during melting were explored in terms of their effect on the resulting surface layer. The wear test system used was computer interfaced and controlled, permitting continuous measurements of wear depth and friction force.