Effect of stress on the crevice corrosion of P110 steel in the CO2-saturated NaCl solution containing thiosulphate/H2S

Abstract

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.