A numerical model for vacuum carburization of an automotive gear ring

Abstract

A vacuum carburizing-heat treatment of an annulus gear ring is simulated via a carburized predictive finite element model that accounts for both heat transfer and carbon diffusion. Profiles of carbon concentration along the depth of the gear ring were calculated and are congruent with measured values, which were obtained by a glow discharge spectrometer (GDS). While sensitive to carbon content, rigorous observation of the microstructures in the gear ring after heat treatment was attempted by transmission electron microscopy (TEM). The finial various martensitic microstructures in several parts of the gear ring may be well explained on the basis of the calculated carbon concentration.