A model for the calculation of the bainitic phase transformation kinetics from dilatometric data

The development of a method for determining phase transformation kinetics f or a multistep solid-state transformation from a dilatation curve is descri bed. The dilatation of steels during a continuous cooling or an isothermal holding of an austenite is analyzed. A model is proposed in which the trans ient dilatation is calculated based on the fraction of the phases present. The model can be applied to calculate the phase transformation kinetics fro m a dilatation U curve of a hypo-eutectoid steel. After verification by com parison with experimental results for an interstitial-free steel, the model is used to calculate the transformation kinetics indicated by the dilatati on curves of a bainitic grade steel. Excellent agreement between the model and experiments has been obtained.