X-ray Studies on Retained Austenite in Tempered High Carbon Steel

Line broadening analyses of the retained austenite and martensite in quenched steel during the process of the low temperature tempering were investigated, and the results obtained are summarized as follows;(1) The integral breadth of the retained austenite increased with decreasing of its volume fraction.(2) For the retained austenite phase, the effective strain increased and the effective particle size decreased with the ageing process, and vice versa for the martensite phase.(3) The dislocation density for martensite was estimated to be 4.7×1012/cm2 after tempering at 180°C for 30 min and it decreased with the ageing process, while that of the retained austenite, which is 5.1×1011/cm2, increased. The stabilization of retained austenite was discussed from these results.