Highly loaded gears are usually casehardened to fulfill the high demands on
the load-carrying capacity. Several factors, such as material, heat treatment, or macro and micro geometry, can influence the load-carrying capacity. Furthermore, the residual stress condition also significantly
influences load-carrying capacity. The residual stress state results from heat treatment and can be further modified by manufacturing processes post heat treatment, e.g. grinding or shot peening.
Press quenching is designed to harden steel gears while minimizing distortion, and the process is especially applied for hardening large diameter thin-wall gears, face gears and bevel gears. The dimensional control aims at maintaining flatness, out-of-round, straightness and consistency of radial size. The press quench tooling and the process design have been mainly experience-based, using a trial and error approach for implementation of new processes, new gear materials and gear configurations.