Minimizing Case/Core Initiated Failures in Induction Hardened Components

Induction case hardening studies are presented showing hardness vs. depth and residual stress vs. depth results on material and prior heat treat combinations with associated induction processing parameters.  The hardness and residual stress levels at the case/core interface and transition region are examined.  The goal is to identify material and processing combinations that will prevent case to core transition initiated failures in pins or shafts with high bending or torsional loads.  Results are discussed with this in mind.  The relationship of case to core transition microstructure, hardness (temper back), and residual stress on the final component fatigue properties is highlighted and future work suggested.