Critical cooling rate on carbide precipitation during quenching of austenitic manganese steel

Critical cooling rate to avoid carbide precipitation during quenching of austenitic manganese steel was investigated by means of optical microscopy, image analyzer and numerical analysis. An efficient heat treatment analysis program including temperature-dependent material properties was developed for the prediction of cooling rate and probability of carbide precipitation during quenching by finite difference method. Time-dependent heat transfer coefficient was adopted to achieve more precise results. Area ratio of carbide precipitation was measured by image analyzer to determine the critical point of carbide precipitation. Temperature-dependent critical cooling rate at that point was calculated by the developed numerical program. Finally, the probability of carbide precipitation on the whole area of specimen can be predicted by the proposed numerical program and the numerical result of a specimen was compared with the experimental result.