Strain-induced transformation in a low carbon microalloyed steel during hot compression testing

Strain-induced transformation (SIT) of austenite to ferrite during hot compression testing of a low carbon microalloyed steel is investigated by using optical microscopy and electron back-scattered diffraction. Microstructural observation indicates that ultrafine ferrite grains of ∼1.5 μm can be obtained by deformation at 845 °C, just above Ar3, with a strain rate of 0.1 s−1 due to the occurrence of SIT of austenite to ferrite.