Calculation of the phase transformation kinetics from a dilatation curve

The change of length of hypoeutectoid steel during a continuous cooling process has been analyzed in detail. A model has been developed in which the transient dilatation is calculated based on the fraction of the phases present and the redistribution of carbon is taken into account. The model has been applied to determinate the phase transformation kinetics from the dilatation data during a cooling process of hypoeutectoid steel. Experiments on interstitial free-steel and C–Mn steel have been carried out, in which the dilatation curves of these steels during a cooling process have been recorded. The transformation kinetics indicated by dilatation curves has been calculated by the use of the model. It is shown that there is excellent agreements between the calculation results and the experiments results, and thus the model is regarded as validated.