应力与环境耦合条件下高强钢S135的疲劳行为北大核心CSCD

为评价应力与环境耦合(交变应力、腐蚀介质和温度耦合)对高强度钢S135疲劳性能的影响,探索应力与环境耦合对高强度钢S135疲劳的作用机制,测试了S135材料在空气中和不同温度下(25、40、60和80℃)有机盐钻井液中的疲劳寿命,分析了S135在有机盐钻井液中的腐蚀疲劳敏感性,并使用扫描电镜观察了不同温度下的断口形貌,研究了有机盐钻井液中S135腐蚀疲劳的断裂机理。结果表明,同一应力(低应力)水平下,随温度升高(25、40、60和80℃),腐蚀疲劳寿命逐渐降低,腐蚀疲劳敏感指数和温度敏感指数逐渐增加。研究认为,交变应力、腐蚀介质和温度耦合对S135材料疲劳有极大的影响,交变应力是疲劳失效的主要因素,腐蚀介质会使S135表面产生腐蚀坑,导致疲劳裂纹的萌生,温度通过加速腐蚀对疲劳破坏产生影响。

Fatigue behavior of high- strength steel S135 under coupling stress with environment

The aim is to evaluate the coupling effects of stress and environmental factors (alternating stress, corrosive medium and temperature) on the fatigue property of high- strength steel S135 and explore the fatigue mechanism of high- strength steel S135 under the coupling action of stress and environmental factors. The fatigue life of S315 materials in air and organic salt drilling fluid at different temperatures (25, 40, 60 and 80??) was tested and the corrosion fatigue sensitivity of S135 in organic salt drilling fluid was analyzed. The fracture morphologies at different temperatures were observed under SEM. Based on the above results, the fracture mechanism of S135 corrosion fatigue in organic salt drilling fluid was studied. Under the same stress level (low stress), with the temperature rise (25, 40, 60 and 80??), the corrosion fatigue life decreased gradually and the corrosion fatigue sensitive indexes and the temperature sensitive indexes increased gradually. It is suggested that the coupling effect of alternating stress, corrosion medium and temperature has a great effect on the fatigue failure of S135 materials. Alternating stress is the main determining factor of fatigue failure. The corrosion medium can cause corrosion pits on the surface of S135, thereby resulting in fatigue crack initiation. Temperature influences fatigue damage by accelerating corrosion.