Influence of Heating Rate and Soaking Temperature during Case-Hardening on the Hardness and Grain Size of Ultra-Clean Gear Steels

Abstract In the framework of a research project, tooth root bending strength high-strength gears is investigated. The most common type failure encountered with these shot-peened, case-hardened breakage caused by crack initiation below surface at non-metallic inclusion (fisheye failure). However, it well known that case-hardening depth and quenching grain size can have great influence on gear’s load carrying capacity. To ensure this project solely investigates inclusions, any cross-influences must be excluded or minimized, least known. in case such ultra-clean gear steels, no recommendations investigations material properties are currently available. Therefore, paper, extended conducted into effects different process steps during resulting steels.