Degradation of artificially corroded galvanized high-strength steel wires: Corrosion morphology and mechanical behavior

Abstract

• Four typical pit morphologies exist on the corroded steel wires. • Pit depth and uniform corrosion depth are in constant competition while the competition tends to stabilize when corrosion loss is more than 10%. • Ductility degradation is greater than strength and the ductility degradation is related to the ratio of pit depth to residual radius. The corrosion morphology of artificially galvanized high-strength steel wires and its effect on mechanical behavior was presented. The corrosion morphology was obtained by 3D optical scanner. Four typical pit morphologies on corroded wires were identified, namely conical pit, hemispherical pit, combined pit and secondary pit. The probabilistic density function of cross-sectional parameters under different corrosion degree were modeled by normal distribution, and the evolution of model parameters was obtained. Based on the proposed evolution model, the maximum cross-sectional area loss was estimated by ‘3 σ rule’ of normal distribution function. Subsequently, the effect of corrosion pits on the mechanical behavior of corroded wires was discussed. It shows that the ductility degradation of corroded wires is much greater than that of strength, the ductility degradation is closely related to the ratio of pit depth to residual radius. Besides, it was found that the probabilistic density function of the ratio of pit depth to uniform corrosion depth tends to stabilize when the corrosion loss is more than 10%, which indicates that the surface of corroded wire with corrosion pits is uniformly thinning.