Metastable pitting behaviour of austenite stainless steel after compressive deformation in an acidic NaCl solution was investigated. The results show that the pit initiation rate increases while both metastable pit lifetime and growth rate decrease after compressive deformation. Meanwhile, the ratio of the surface oxide fraction of Cr to Fe increases whereas the average size of stable pits is smaller and shallow disk‐shaped under compressive residual stress. The results reveal that with the aid of enrichment of Cr oxides and compressive residual stress, which helps break the remnants of the undermined passive film, pit repassivation can be accelerated.

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The influence of cold U‐bending on pitting corrosion of 304L stainless steel in an acidic NaCl solution is investigated using surface analyses and electrochemical measurements. The pitting behavior of the exterior and interior surfaces of U‐bended specimen exhibiting tensile and compressive residual stress respectively are both considered. The results show that microstructural modification by U‐bending promotes the pit nucleation. Considering the passive film properties after U‐bending, no significant change in both the thickness and Cr/Fe ratios of the passive films formed on the two deformed surfaces can be found. The accompanying residual stresses after U‐bending, especially the tensile residual stress, exhibits a remarkable acceleration of the metastable pit growth rate. Therefore, the pitting potential declines significantly for the exterior surface of U‐bended specimen. However, the compressive residual stress in the interior surface facilitates the repassivation of the metastable pit, can nullify the negative effect of microdefects for the pitting corrosion resistance, so that the pitting potential of the interior surface of U‐bended specimen does not decrease.

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