Prediction of Bainite Start Temperature in Alloy Steels with Different Grain Sizes

摘要

Bainite microstructure in alloy steels yields materials with an excellent combination of mechanical properties such as high strength and toughness, resistance to creep and fatigue, and hydrogen embrittlement. During cooling, bainite transformation is initiated at the bainite start (B_s) temperature, which is the highest isothermal temperature at which upper bainite is observed, and ceases when the temperature reaches the martensite start (M_s) temperature. Addition of alloying elements mostly lowers the B_s temperature. Especially, carbon and manganese known as strong austenite stabilizing elements effectively decrease the B_s temperature.