Corrosion of high-strength steel in 3.5% NaCl solution under hydrostatic pressure: Initial corrosion with tensile stress coupling

The rust development on Ni-Cr-Mo-V high strength steel under hydrostatic pressure and tensile stress was investigated by microstructure characterization and electrochemical measurements. Deposition influenced by hydrostatic pressure and tensile stress shows two periods: the first stage of immersion, both hydrostatic pressure and tensile stress control the deposition of corrosion products, such as Cr ³⁺ ; the later stage of immersion, only hydrostatic pressure contributes to the growth of rust, thus forming an inner rust layer with a large number of cracks; therefore, the worse protection of rust layer, which contains much β-FeOOH and Fe ₃O ₄, formed under the simulated deep-sea environment.