Cold Rolling Effect on the Microstructure and Pitting Resistance of the NBR ISO 5832-1 Austenitic Stainless Steel

The aim of this work is to assess the influence of cold rolling on the microstructure and pitting resistance of the NBR ISO 5832-1 austenitic stainless steel. Samples of this stainless steel either with deformation, corresponding to 30%, 50% and 70% of reduction in thickness induced by cold rolling, or without deformation (as received), were characterized regarding their microstructure to investigate the metallurgical effects created during the deformation process. The results showed that certain levels of cold rolling (30% and 50%) decreased the corrosion resistance of the stainless steel by causing inclusions fragmentation and voids at the matrix-inclusion interface, whereas unexpectedly, high levels of cold deformation (70%) resulted in improved localized corrosion resistance. Surface observation showed that for this level of deformation, the voids created by fragmentation and the matrix-inclusion interface were shielded with matrix material.