Numerical modeling and simulation of carburized and nitrided quenching process

In order to study metallo-thermo-mechanical behavior during carburized and nitrided quenching, a numerical model when considering quantitative effects of diffused carbon and nitrogen gradients and kinetics of phase transformation is proposed. Coupled calculations of diffusion, phase transformation and stress/strain give the final distributions of carbon and nitrogen contents as well as residual stress and distortion. Within the numerical simulation method, the effects of both transformation and lattice expansion induced from carbon and nitrogen absorption are considered when calculating the evolution of the internal stress and strain. In order to verify the method of numerical simulation, the simulated distributions of carbon and nitrogen content and residual stress/strain of a cylinder during carburized and nitrided quenching are compared with the measured results.