Estimation method for the fatigue limit of case hardened steels

It is well known that estimation of fatigue limit and optimum effective case depth are an important area of interest to the design engineer. In this study, simple expressions for the case hardened steels have been proposed to estimate the bending fatigue limit and optimum case depth values. Validation of the proposed expression was carried out several nitrided low alloy and carburised steels with different case depths. Results showed that the proposed analytical methods have good agreement with the experimental fatigue limit, and estimated optimum effective case depth values are favourable from the practical point of view. In case of considering 23 different effective case depth values of the steels with core hardness values are in range of 190-290HB, the calculated absolute mean deviation in estimating fatigue limit is 5.5%.