Evaluation of sensitization and self-healing in austenitic stainless steels based on simulations of Cr-depleted zones

A simulation of the grain boundary precipitation of the Cr-rich carbide, M₂₃C₆, in austenitic stainless steels has been carried out using the DICTRA software package employing kinetic and thermodynamic databases. Our calculations reproduced the evolution of the Cr-depleted zone close to M₂₃C₆ carbide and the disappearance of the zone after a long annealing time. In addition, the calculated time- temperaturesensitization diagrams were in line with the experimental results of typical corrosion trends with annealing time. According to our results, despite the simple treatment used, a reasonable approximation for the simulations was to set the initial width of the austenite region from which the carbon was drawn as a sixth of the grain size. We also confirmed that the onset of sensitization for a steel with 0.1 mass%C shifted to shorter times and to higher temperatures compared with a steel with 0.06 mass%C.