Numerical Simulation of Reaction-Diffusion during Carburization of HK40 Steel

摘要

Two types of carbides M_(23)C_6 and M_7C_3 precipitate orderly as carbon concentration in a high Cr-Ni austenitic steel increases during carburization process. The mathematical model that describes diffusion of carbon and the precipitation of M_(23)C_6 and M_7C_3 has been studied. A criterion to judge when the transformation of M_(23)C_6 to M_7C_3 is over and M_7C_3 precipitates directly has been given in simulated calculation. By applying the model, the carburization of HK40 steel has been calculated by means of finite difference computation techniques. The pack carburization tests for the HK40 steel have been carried out at 1273 K. The comparison between the experimental and the calculated results show acceptable agreement.