Effect of austenite grain size on kinetics of dynamic ferrite transformation in low carbon steel

The effect of austenite grain size on kinetics of dynamic ferrite transformation above Ae3 in a 6Ni–0.1C steel was studied. As the austenite grain size decreased, the onset of dynamic transformation was accelerated. The increase in the fraction of dynamically transformed ferrite was in good agreement with the change in flow stress, i.e. dynamic softening. The kinetics of dynamic transformation could be evaluated by an Avrami-type formula.