Modeling research on pearlite-to-austenite transformation in hypereutectoid steel containing Cr

Analytical models of the diffusion controlled pearlite-to-austenite transformation during isothermal and uniform heating processes are presented. The solute elements diffusing through the volume of austenite and the interfaces between austenite and pearlite were both considered synchronously. The austenite formation from pearlite of a Fe-1C-1.44Cr steel was calculated with the present model and the results were compared to the experimental results. Calculation results show that the transformation is Cr diffusion-controlled and C diffusion-controlled below and above the transition temperature of austenite growth (so called PNTT), respectively. The theory about PNTT is quantitatively proved to be right. •An austenitization model for hypereutectoid low alloy steel is presented.•Volume diffusion and boundary diffusion are considered in the model.•Dilatometric experimental results are compared with the calculated results.•Austenitization mechanism is discussed based on the new model.