This paper proposes a novel corrosion fatigue life estimation methodology considering the effect of hot corrosion and non-uniform stress field. The period of corrosion pit growing to the critical size was assessed by Faraday law. According to the cyclically plastic material constitutive response of smooth specimen, the finite element analysis was performed by regarding the critical corrosion pit as a micro semi-ellipsoidal notch. A novel definition about the effective strain was proposed considering the effect of non-uniform stress field in the high stress zone. The fatigue life from pit formation to final fracture was estimated by introducing the defined effective strain amplitude into Manson-Coffin-Basquin, Morrow, SWT and Walker models. Compared with the existing classical approaches, such as hot spot-based, continuum damage mechanics-based, strain energy-based models, the proposed approach provided significantly better corrosion fatigue life prediction. Finally, Walker model was suggested as the most suitable one after further discussion about the effect of mean stress.

本文提出了一种考虑热腐蚀和非均匀应力场影响的新型腐蚀疲劳寿命估计方法。腐蚀坑增长到临界尺寸的时间由法拉第定律评估。根据光滑试样的循环塑性材料本构响应，将临界腐蚀坑视为微半椭圆形缺口进行有限元分析。考虑到高应力区非均匀应力场的影响，提出了有效应变的新定义。通过将定义的有效应变幅引入 Manson-Coffin-Basquin、Morrow、SWT 和 Walker 模型，估计从凹坑形成到最终断裂的疲劳寿命。与现有的基于热点、连续损伤力学等经典方法相比，基于应变能的模型，所提出的方法提供了显着更好的腐蚀疲劳寿命预测。最后，在进一步讨论平均应力的影响后，Walker 模型被认为是最合适的模型。