海洋腐蚀环境下Q690高强钢材#br#疲劳性能试验研究

根据海洋浪溅区的特征，对Q690高强钢材进行了室内加速腐蚀与高周疲劳试验，拟合不同腐蚀周期试件的S-N曲线，研究了腐蚀损伤对其疲劳性能的影响，基于损伤理论分析了钢材腐蚀疲劳破坏程度，通过断口微观扫描揭示了裂纹扩展规律。结果表明：随着腐蚀周期增加，钢材损伤程度逐渐增大，腐蚀100d的质量损失率ηs和腐蚀速率K分别为7.21%、1.342mm/a。Q690高强钢的疲劳寿命受应力水平和腐蚀损伤耦合影响程度明显，在低应力水平下，腐蚀周期为60d时，试件的疲劳极限值降低了30.15%。损伤指数可以反映腐蚀疲劳中材料内部的损伤规律，随着应力水平的增加，损伤程度提高，疲劳裂纹间距增大。

Experimental research on fatigue performance of Q690 #br#high strength steel in marine corrosive environment

According to the characteristics of ocean splash zone, indoor accelerated corrosion and high cycle fatigue tests were carried out on Q690 high strength steel. The S-N curves of specimens with different corrosion cycle were fit, and the effect of corrosion damage on its fatigue performance was studied. Based on the damage theory, the degree of steel corrosion fatigue damage was revealed, and the law of crack growth was observed using microscopic scanning of fracture. The results showed that the degree of steel damage increased gradually with the corrosion period. The mass loss rate ηs and the corrosion rate K for 100 days of corrosion are 7.21% and 1.342 mm/a, respectively. The fatigue life of Q690 high strength steel is significantly affected by the coupling of stress level and corrosion damage. At a low stress level, when the corrosion time is 60d, the fatigue limit value of specimen is reduced by 30.15%. Damage index can reflect the internal damage law of material in corrosion fatigue. Both the damage degree and the fatigue crack spacing increase with the stress level.