Transition from Diffusive to Displacive Austenite Reversion in Low-Alloy Steel

For understanding the transition from diffusive to displacive austenite reversion mechanism in steel, the effect of heating rate on austenite reversion behavior was investigated in 0.15%C–5%Mn steel. Austenite reversion temperature first increased gradually with the heating rate owing to the superheating effect and then remained at a constant temperature above a critical heating rate. In response, the austenite formed by rapid heating exhibited a coarse prior austenite grain structure, indicating the occurrence of displacive reversion even in low-alloy steel.