Effect of cold deformation on the corrosion behaviour of UNS S31803 duplex stainless steel in simulated concrete pore solution

The effect of cold deformation on the corrosion and passivation behaviour of UNS S31803 duplex stainless steel in saturated Ca(OH)2 solution containing 3.5 wt.% NaCl was investigated. The results demonstrated that cold deformation changes the internal microstructure of two phases. Cold deformation was detrimental to the pitting corrosion resistance of duplex stainless steel. Metastable pitting events were enhanced by cold deformation. It also revealed that metastable pit initiation sites transfer from austenite phase to ferrite phase at cold deformation level higher than 70%. Moreover, compositions change and dehydration effect in the passive film were also related to cold deformation.