Mathematical Model Coupling Phase Transformations and Temperature Fvolutions in Steels

Abstract

A mathematical model for calculating phase transformations in steels during rapid heating and cooling is presented. It is based on a rule of additivity. The isothermal kinetics are modelled by Johnson-Mehl-Avrami law. The model des6ribes the kinetics of austenitization during heating. the state of austenite at the end of heating (carbon content, grain size), the kinetics of transformations during cooling. the final microstructure and hardness. The model is worked out firstly on dilatometric specimenswithout thermal gradients in order to validate the modelling and the input data. Thenthe application of the model to massive cylinders heated up and cooled downwith high thermal gradients is presented. © 1992, The Iron and Steel Institute of Japan. All rights reserved.