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.