Residual Stress, Hardened Layer and Bending Fatigue Strength of Induction Hardened Sintered Metal Gears

Abstract

A 3D-FEM simulation program for induction hardening of sintered metal gears was made up. An electromagnetic field analysis, a heat conduction analysis and an elastic-plastic stress analysis during the induction hardening process of sintered metal gears were carried out by using this program, considering changes of the magnetic permeability, the resistivity, the thermal expansion coefficient and the yield stress with the temperature. The measurement of hardness distribution and the bending fatigue test of induction hardened sintered metal gears were performed. Effects of the heating time on residual stress, hardened layer and bending fatigue strength of induction hardened sintered metal gears were examined, and compared with those of induction hardened wrought steel (S35C) gears.