Prediction model for the austenite grain growth in a hot rolled dual phase steel

The main purpose of this work is to develop a pragmatic model to predict isothermal austenite grain growth in a hot rolled dual phase steel. Austenite grain growth kinetics have been studied in different heating conditions, involving soaking time and soaking temperature as well as heating rate. The contribution of the initial grain size to the time exponent in Beck equation was analyzed mathematically. The time exponent and initial grain size were also quantitatively described by models proposed. It was found that the time exponent value which had a wide range increased when the temperature decreased. No meaningful activation energy can be obtained for the grain growth process when the time exponent varies. The initial grain size increases with the soaking temperature. The model predictions present a good agreement with experimental austenite grain growth data.

► We analyzed the effect of initial grain size on time exponent mathematically. ► We studied the initial grain size in different heating conditions and proposed the model. ► The time exponent value which had a wide range increased when the soaking temperature decreased. ► A model for the time exponent was proposed. ► The model for isothermal austenite grain growth was developed.