Prediction of Fatigue Life of 45 Steel Subjected to Quenching Tempering under Variable Amplitude Loading

Overloading tests and fatigue tests of 45 quenching tempering steel were carried out to further check whether or not the procedures developed by us were generally applicable for predicting the fatigue life and it′s probability distribution under variable amplitude loading. Test results and analysis results have show that the overloading effect factor Z of this steel notched elements is equal to zero, thus the effect of loading sequence needs not to be considered in life prediction. The fatigue life of this steel under variable amplitude loading can be directly predicted by using the Miner′s rule and the expressions of fatigue life under constant amplitude loading. The test results are in good agreement with the prediction results.