Prediction of Prior Austenite Grain Size of High-phosphorous Steels through Phase Transformation Simulation

抄録

The effects of phosphorous content and cooling rate on the phase evolution of low carbon steels were analyzed by DICTRA simulation focusing on the micro-segregation behavior of phosphorous during solidification and subsequent cooling process. Through the phase transformation simulation, the effects of metallurgical parameters such as P content, cooling rate, and primary dendrite arm spacing on the starting temperature of austenite grain growth were clarified. Using the values of austenite grain growth starting temperature calculated by the phase transformation simulation, prior austenite grain size of low carbon steels were estimated based on a classical grain growth modeling in a P content range from 0.01 to 0.20 mass% and in a wide cooling rate range from 1.7 to 800 K s⁻¹. The prior austenite grain size predicted with the present approach showed good agreement with a group of selected experimental data of 100 mm thick slabs and 2 mm thick strips.