Phase Stability of Residual Austenite in 60Si2Mn Steels Treated by Quenching and Partitioning

The residual austenite and its stability in commercial 60Si2Mn steel treated by quenching and partitioning (Q-P) were investigated. The Q-P heat treatment was carried out using a system of ordinary electric furnace—oil bath box—electric furnace. Cryogenic treatments at different temperatures were performed to assess the thermal stability of residual austenite. The microstructure, particularly residual austenite, was analyzed using optical microscope and X-ray diffraction (XRD), and the microhardness and Rockwell hardness were measured. The residual austenite with the volume fraction as much as 13.7% and the HRC hardness level of 41 were achieved, and the residual austenite is relatively stable.