Research on the Equivalent Constitutive Model of Randomly Corroded High‐Performance Steel Q550E

To efficiently characterize the impact of random corrosion on the mechanical properties of steel, the random corrosion morphology and equivalent constitutive model of high‐performance steel (HPS) Q550E are studied in this paper. First, 3D scanning is performed on Q550E HPS specimens to explore their corrosion morphology and pit distribution characteristics. The mechanical property parameters and degradation laws of the specimens are obtained by static tensile tests. Subsequently, a finite element simulation method for random corrosion is proposed to assess the effects of pit morphology on mechanical responses. Finally, an equivalent thickness method is developed, incorporating the three‐dimensional geometry, type, and proportion of corrosion pits. Model parameters are recalibrated and validated against the three‐stage constitutive model. Results show that the mean value of rectangularity is negatively correlated with the corrosion rate, but positively correlated with the average cross‐sectional area. Key mechanical indicators degrade linearly with rising corrosion severity. The equivalent thickness model is proved to be superior to the traditional method, and the developed constitutive model can accurately reproduce the stress‐strain response of corroded HPS. The research results provide a reference for the performance evaluation and safety design of HPS structures in corrosive environments.