Construction of best-fit fatigue curves considering material properties and loading modes

In this study, best-fit fatigue curves are constructed considering material properties and loading modes. Three common fatigue test methods (rotating bending, axial load-controlled and strain-controlled) are compared, and their scopes of applications are clarified. The best-fit fatigue curves are given as a function of tensile strength and have been constructed based on the strain-controlled fatigue test data. The comparison of the best-fit fatigue curves with the axial load-controlled test data reveals that both deviated from each other for the carbon and low-alloy steels and the austenitic stainless steel. Therefore, the best-fit fatigue curves are reconstructed considering the data by the rotating bending fatigue test and the axial load-controlled fatigue test. In the case of the carbon and low-alloy steels, the best-fit fatigue curves are classified by two kinds of microstructures. In the case of the austenitic stainless steel, the best-fit fatigue curves are classified by two kinds of loading modes. Finally, design factors based on the reliability of best-fit fatigue curves are specifically presented.