Kinetics of Phase Transformations in Steels: A New Method for Analysing Dilatometric Results

Abstract

A dilatation curve records the detail of the phase transformation kinetics. The dilatometric technique may be applicable to the investigation of the phase transformation kinetics if the information contained in the dilatation curve can be extracted effectively. A detailed analysis has been made of the length change of a hypoeutectoid steel during a continuous cooling. A model has been developed in which the transient dilatation is calculated based on the fraction of the phases present. The model takes into account the redistribution of carbon and is applicable to the determination of the phase transformation kinetics from the dilatation data during a cooling of a hypo-eutectoid steel. The model was validated by comparing the model results with the experimental results of an interstitial free steel. Experiments have been done with a bainitic steel. The model has been applied to the determination of the phase transformation kinetics from the dilatation curves of this steel. Excellent agreements between the model and experiments have been obtained.