Impact of plastic deformation on the corrosion behavior of S32304 duplex steel in a simulated industrial solution

Abstract This study investigated the impact of different deformations on the corrosion resistance of duplex stainless steel in an industrial environment simulation solution using various electrochemical, electron backscatter diffraction analysis, and surface analysis methods. Electrochemical results show that under small deformation conditions (10 %), the corrosion current of S32304 duplex stainless steel decreases due to the coupling effect of the austenite phase with increased potential and the ferrite phase with decreased potential. However, due to the increased potential difference between the austenite and ferrite phases, the pitting corrosion resistance of the material decreases. Under large deformation conditions, the corrosion current of S32304 duplex stainless steel continuously increases but still remains lower than the corrosion current under undeformed conditions. The pitting potential of duplex stainless steel first decreases and then increases. When the deformation reaches 70 %, high-angle grain boundaries are formed in the austenite phase, leading to a sharp decrease in potential. The potential of austenite begins to be lower than that of ferrite, and the preferentially corroded phase changes from ferrite to austenite. The experimental results found that deformation does not affect the semiconductor properties of the passivation film of S32304 duplex stainless steel. The main components of its passivation film include iron oxides (FeO and Fe 2 O 3 ) and chromium oxides (Cr 2 O 3 and Cr(OH) 3 ).