The fatigue assessment methods considering surface strengthening process were proposed through experimental investigation of fatigue properties of carburized Cr-Ni alloy under stress ratios of 0 and 0.3. Interior-failure is caused by continuous debondings of refined grains due to stress concentration around interior-inclusion, while surface-failure is caused by grain dislocation slip around surface-inclusion. In view of the effect of local equivalent stress (residual stress, mean stress and stress concentration around the inclusion), the P_Rx-S-N curves of carburized Cr-Ni alloy steel were constructed based on the prediction of crack characteristic sizes by Generalized Extreme Values (GEV) and Generalized Pareto (GP) distributions under different cumulative probabilities, and the comparison shows that GP distribution can predict the fatigue strength better than GEV distribution. The fatigue life prediction models can be established by GP distribution for surface and interior failures, and the predicted results are in good agreement with the experimental results.

通过对渗碳Cr-Ni合金在0和0.3的应力比下的疲劳性能进行实验研究，提出了考虑表面强化工艺的疲劳评估方法。内部破坏是由于内部夹杂物周围的应力集中而导致的细化晶粒的连续脱胶引起的，而表面破坏是由于内部夹杂物周围的晶粒错位滑移引起的。考虑到局部等效应力（残余应力，平均应力和夹杂物周围的应力集中）的影响，P _Rx -SN基于不同累积概率下的广义极值（GEV）和广义帕累托（GP）分布预测裂纹特征尺寸，建立了渗碳Cr-Ni合金钢的曲线，比较表明，GP分布可以较好地预测疲劳强度。比GEV发行。可以通过GP分布建立表面和内部失效的疲劳寿命预测模型，预测结果与实验结果吻合良好。