Comparative study on surface morphology evolution and mechanical property degradation of galvanized steel under different corrosion tests and its service life prediction

Corrosion poses a major engineering challenge that affects the durability of structures, and galvanized steel is commonly used due to its excellent corrosion resistance. Although extensive research has been conducted on steel corrosion, there is limited comparative research on galvanized steel in different accelerated corrosion methods. And the research on the post-corrosion morphology and mechanical degradation of galvanized steel is also insufficient. This study investigated galvanized steel's corrosion behavior under salt spray and electrochemical corrosion tests. Weight-loss, surface morphological evolution, and mechanical property degradation at original and corroded sections were analyzed, revealing correlations between corrosion depth and mechanical degradation. Service life predictions were derived from fitted degradation models and residual mechanical properties. Key findings include：(1) Salt spray specimens exhibited rougher surfaces, with corrosion depths showing good consistency between morphological observation and weight-loss measurements; (2) Electrochemical corrosion demonstrated excellent controllability, though current density influenced both corrosion depth and mechanical performance; (3) Yield strength showed greater corrosion sensitivity than ultimate strength, with mechanical degradation displaying a near-linear relationship to corrosion depth; (4) Galvanized steel exhibits high service-life risk in aggressive C5-CX environments. This study fills a research gap by linking corrosion morphology and mechanical degradation of galvanized steel, enabling service life prediction in atmospheric environments. • The corrosion of galvanized steel by different corrosion methods was compared. • The morphology under salt spray test is rougher than electrochemical corrosion. • Yield strength is more sensitive to corrosion than ultimate strength. • Service life under C3 to CX category atmosphere environments was predicted.