Relationship between fatigue limit and Vickers hardness in steels

In this work, a method to predict the fatigue limit by using Vickers hardness measurements is proposed. Tests carried out in small regions of different annealed, quenched and quenched-tempered alloy steels allowed an improvement of the empirical Murakami–Endoʹs equation. s method, the plastic deformation caused by the indentation is assumed to be the defect from which the process of initiation and propagation of cracks originate, analogously to small cracks. e limits for four kinds of steels in different metallurgical states (annealed, quenched and quenched-tempered) were estimated in two different ways, and the obtained values were compared to the experimental ones. A good correlation between Vickers hardness and the fatigue limits estimated by direct plastic deformation zone measurements using optical microscopy was envisaged.