Very high cycle fatigue behaviors of Mn–Si–Cr series Bainite/Martensite dual phase steels

The present work studied the very high cycle fatigue (VHCF) behaviors of Mn–Si–Cr series Bainite/Martensite (B/M) dual phase high-strength low-alloy (HSLA) steels to ensure safe applications in railway and oil field. Four kinds of chemical compositions and seven types of B/M steels were designed and studied by ultrasonic fatigue test. The conception of apparent and intrinsic VHCF strength is addressed. Results show the effect of heat generation cannot be ignored in B/M steels in ultrasonic fatigue test, and higher is the intrinsic VHCF strength of materials, more remarkable is the negative effect of self-heating. More importantly, the VHCF property of B/M steels is less sensitive to the inclusion than that of tempered martensite steels, and the amount of retained austenite puts little effect on the VHCF property.