Analysis on Microstructure and Properties of Testing Bainitic Rail Steel

The mechanical properties and microstructure of experimental bainitic rail steels were studied. The mechanical properties and microstructure in rolled condition and tempered condition were compared. The notch sensitivity to the rail gap was studied. The research results show that new experimental bainitic rail steels have high tensile strength and high yield strength, higher toughness, and is not sensitive to the notch. The microstructure of rolled condition and tempered condition experimental rail steels are bainite and martensite-austenite islands(B +M-A microstructure). The distribution bainite likes needle and rod shap, is upper bainite. After 300 ℃ tempering, the plasticity and toughness increase. The notch sensitivity decreases and the number of M-A microstructure reduces.