The effect and general relation of loading frequency on fatigue life of 316L stainless steel

The frequency effect constitutes a key issue in the acceleration technology of high cycle fatigue testing. In this study, fatigue tests were conducted on an austenitic steel at frequencies of 600 Hz, 1 kHz by vibration fatigue, and 20 kHz ultrasonic bending fatigue up to high cycle regime, respectively. The gauge section and loading form of the specimen were designed in the same condition to avoid influence from the volume effect and stress state, and to ensure the fatigue data are fully comparable. The results demonstrated that the fatigue properties were significantly affected by frequencies. Nevertheless, fractographic analysis revealed that the fracture mechanism remained the same. Therefore, we established a correlation between the frequency and the parameters of the Basquin formula, which was found suitable to predict fatigue life for results in articles with other frequencies. Subsequently, a general life prediction model was provided with improved accuracy by accounting for the impact of strain rate and temperature rise in different frequencies. In this model, the fatigue life under a given frequency and loading amplitude could be effectively predicted merely by using the fatigue data at 20 kHz, which means that the model may applied to convert data on the fatigue life among different frequencies.