Corrosion fatigue behaviour of Q690D high-strength steel considering the effect of coupling

During the service period of steel structures, the condition of suffering from environmental corrosions and fatigue loadings simultaneously widely exists. In this article, focusing on the corrosion fatigue behaviour of Q690D high-strength steel with consideration of the coupling effect, experimental research was conducted and the coupling effect was analysed. Corrosion fatigue coupling tests were performed with the method of electrolytic accelerated corrosion. The corrosion characteristics were studied and compared with the corrosion tests without loadings. Then, the corrosion fatigue S-N curve was established and compared with non-corroded and pre-corroded conditions. Morphology observations were carried out to further analyse the mechanisms of corrosion fatigue coupling. The results show that the fatigue resistance of Q690D high-strength steel deteriorated greatly compared with non-corroded and pre-corroded conditions, and the adverse effect of corrosion fatigue coupling on fatigue resistance cannot be neglected. The coupling effect under real engineering service conditions could be well represented with the adopted test method, taking into account the time dimension correlation between fatigue and corrosion. The established Q690D S-N curve under the corrosive environment provides important references for the residual fatigue life assessment of high-strength steel fatigue considering the effect of environmental deterioration.