Corrosion behavior of Cr–Ni alloyed 690 MPa-grade high-strength weathering steel in simulated marine atmospheres

In this study, the corrosion behavior of Cr–Ni alloyed 690 MPa-grade weathering steel in simulated marine atmospheric environments was investigated in comparison with commercial E690 steel. After wet/dry cyclic corrosion testing, the corrosion resistance was quantitatively evaluated by weight-loss measurements, while the evolution, structure, and composition of the rust layers formed on the Cr–Ni alloyed 690 MPa weathering steel and commercial E690 steel were characterized using SEM, energy-dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical measurements. The alloying elements Cr and Ni facilitate the development of a compact and protective rust layer by promoting the enrichment of Cr- and Ni-containing oxides and the formation of α -FeOOH, thereby significantly enhancing the corrosion resistance of the E690 weathering steel from the initial stage of corrosion. Furthermore, the Cr–Ni alloyed weathering steel forms a cation-selective rust layer during the corrosion process, which effectively suppresses the penetration of Cl⁻ ions and exhibits superior localized corrosion resistance.