Phase transformations in low-carbon steels ; modelling the kinetics in terms of the interface mobility

The mechanical properties of steel are determined by the microstructure that develops during the production process and is a joint result of effects of chemical composition and of heat treatment. This paper deals with the kinetics of the phase transformation between the high temperature FCC-phase austenite and the low temperature BCC-phase ferrite as it occurs during controlled cooling. In order to predict the transformation kinetics, a physical model has been developed that considers both composition effects and the actual lattice transformation rate. The model is verified against experimental dilatometry data for three lean carbon-manganese steel grades. Notwithstanding the model having no adjustable parameters, it yields adequate simulations of the transformation kinetics