ABSTRACT

The effect of stress on the crevice corrosion of P110 carbon steel in the CO₂-saturated 3.5 wt-% NaCl solution with a small amount of thiosulphate/H₂S was investigated. The results showed that the composition of corrosion products on the steel surface did not change with elastic stress while the mackinawite film formed at the crevice mouth was more easily spalled off under higher stresses. Further, the elastic stress likely promoted localised corrosion but inhibited uniform corrosion both inside and outside crevice. Increasing the applied stress led to a deeper and sharper corrosion groove covering with corrosion products at the crevice mouth, suggesting the crevice corrosion was promoted by the applied stress. This is likely due to the peeling of mackinawite film and stress concentration at the crevice mouth.

摘要

应力对含少量硫代硫酸盐/H ₂的CO ₂饱和3.5 wt-% NaCl溶液中P110碳钢缝隙腐蚀的影响S进行了调查。结果表明，钢表面腐蚀产物的成分不随弹性应力而变化，而在较高应力下，缝隙口处形成的马氏体膜更容易剥落。此外，弹性应力可能会促进局部腐蚀，但会抑制缝隙内外的均匀腐蚀。增加外加应力导致缝隙口处腐蚀产物覆盖更深、更锐利，表明外加应力促进了缝隙腐蚀。这可能是由于mackinawite薄膜的剥落和缝隙口处的应力集中。