Numerical simulation of cooling a 2D square block considering phase transformation and changes in thermodynamic properties

During a cooling process, a high-temperature steel usually in austenite phase undergoes a phase transformation to ferrite and bainite. Due to the phase transformation, the material changes its metallurgical structure and hence its mechanical characteristics, including the strength and toughness. In addition, the phase transformation causes a related exothermic reaction and changes the thermodynamic properties. Therefore, the cooling process and its relevant phase transformation should be treated together by coupling them. In this study, the cooling process of a two-dimensional square steel block is investigated numerically by considering the phase transformation from austenite to ferrite. The Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation (Avrami, 1939) was adopted for the phase transformation analysis. The cooling results with and without consideration of the phase transformation effect are compared.