Influence of strain-induced martensite in the anodic dissolution of austenitic stainless steels in acid medium

The anodic dissolution of austenitic stainless steel bars in an acid medium (0.5 M HCl + 2 M H2SO4) under different polarizations is studied. The material comes from bars formed by hot working (HW) and by cold working (CW). UNS S30403 and S31603 grades are considered. The determining effect of alloying elements and working method are proved. The morphology of the attack at different anodic potentials is analyzed. The important influence of the amount and distribution of strain-induced martensite on corrosion is demonstrated. The effect of the martensite on the anodic polarization curves is quantified using specifically designed software.

► Influence of the strain-induced martensite in the corrosion behavior in acid.
► Explanation for the shape of the active peak in austenitic stainless steels.
► Dependence of the corrosion morphology on anodic overpotential.
► Quantification of the influence of microstructure in anodic polarization curves.