MICROSCOPIC MODELING OF FUNDAMENTAL PHASE-TRANSFORMATIONS IN CONTINUOUS CASTINGS OF STEEL

A model has been developed to describe the microscopic behavior of phase transformation of carbon steels in the range of cooling rate occurring in continuous casting. In the liquid- to solid-phase transformation, this model simulates the phenomena of dendrite nucleation and growth during solidification. Both delta- and gamma-dendrites are involved. The nucleation and growth model has been established on the basis of published experimental data and previous work. Also, a model of the peritectic transformation of carbon steels has been included. In the solid- to solid-phase transformation, the model considers the delta --> gamma, gamma --> alpha, and gamma --> alpha + Fe3C phase transformations. The delta --> gamma and gamma --> alpha-phase transformations have been modeled by using the Johnson-Mehl equation, also known as the Avrami equation. For the pearlite transformation, a nucleation law, as well as the growth kinetics, has been established. Good agreement has been found between the prediction of the model and the experimental data.