High-cycle bending fatigue behaviour of nanostructured bainitic steel

The high-cycle bending fatigue behaviour of high-carbon Si–Al-rich steel with a nanostructured bainitic microstructure was studied. A fatigue limit for no failure in 107 cycles of the nanostructured bainitic steel is determined not only by hardness or strength, which determines the fatigue limit of conventional high- and ultrahigh-strength low-alloy steels, but also by microstructure. Retained austenite and secondary cracks in fatigue fractures of the nanostructured bainitic steel have positive effects on the fatigue property.