Effect of Grain Size and Cooling Rate on the Martensite Start Temperature of Stainless Steel
Chengcheng Liu, Minping Huang, Qiang Ren, Ying Ren, Lifeng Zhang
Abstract
Herein, the transformation process of the martensitic stainless steel under different austenite temperatures, holding times, and cooling rates were in situ observed using the confocal laser scanning microscope. The grain boundary migration energy of the austenite grain was 241.51 kJ mol −1 . The grain size at different temperatures and holding times was predicted, agreeing well with measured values. The relationship between the martensite start temperature and the grain size is proposed. The martensitic start temperature was significantly influenced by the cooling rate. With the increase of the cooling rate, the martensitic start temperature first decreased then rose up due to the quenching vacancy and internal stress, respectively.