Heat Treatment Simulation Considering Anisotropy Caused by Micro Segregation

Abstract

The thermo-elastoplastic analyses considering the phase transformation are widely used to predict the residual stress and distortion going with the heat treatment. The ordinary steels often have micro segregation which affects the quenching deformation. General heat treatment simulations are not able to consider the micro segregation since the object is treated as a homogeneous mixture of multiple phases. It is necessary to perform analysis considering the effect of micro segregation in order to predict quenching deformation with high accuracy. In this paper, the elastoplastic constitutive equation expressing the effect of micro segregation with anisotropy of macroscopic material properties are formulated, and the heat treatment simulations considering micro segregation are performed based on the proposed formulation. Carburizing and quenching tests are conducted on round bars with and without micro segregation. It is confirmed that the analysis considering the effect of micro segregation with an anisotropy of transformation plasticity model reproduces the experimental results in which micro segregation increases the quenching deformation.