Modeling austenite–ferrite transformation in low carbon steel using the cellular automaton method

Austenite–ferrite transformation at different isothermal temperatures in low carbon steel was investigated by a two-dimensional cellular automaton approach, which provides a simple solution for the difficult moving boundary problem that governs the ferrite graun growth. In this paper, a classical model for ferrite nucleation at austenite graun boundaries is adopted, and the kinetics of ferrite graun growth is numerically resolved by coupling carbon diffusion process in austenite and austenite–ferrite (γ–6ga) interface dynamics. The simulated morphology of ferrite grauns shows that the γ–α-interface is stable. In this cellular automaton model, the γ–α-interface mobility and carbon diffusion rate at austenite graun boundaries are assumed to be higher than those in austenite graun interiors. This has influence on the morphology of ferrite grauns. Finally, the modeled ferrite transformation kinetics at different isothermal temperatures is compared with the experiments in the literature and the grid size effects of simulated results are investigated by changing the cell length of cellular automaton model in a set of calculations.