Experimental research on fatigue performance of Q690 #br#
high strength steel in marine corrosive environment
Guo Hongchao1 Wei Huanhuan1 Yang Dixiong2 Liu Yunhe1 Wang Zhenshan1 Tian Jianbo1
1. Xi’an University of Technology, Xi’an 710048, China;
2. State Key Laboratory for Structural Analysis of Industrial Equipment, Dalian University of Technology, Dalian 116023, China
Abstract：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.
