Pitting susceptibility of AISI 304 stainless steel after cold rolling

Abstract

The austenitic grade AISI 304 stainless steel is traditionally employed for processing equipment in chemical plants due to its relatively good corrosion resistance and mechanical stability. However, it is susceptible to pitting corrosion due to chloride attack which can lead to catastrophic failures during operation. Cold rolling of the metallic sheets used to construct equipment such as tanks and pressure vessels can further aggravate the situation by increasing the material’s susceptibility to localized corrosion. In this work the pitting corrosion resistance of cold rolled AISI 304 stainless steel plates was assessed using chronoamperometric curves and potentiodynamic polarization curves. Cold rolling was performed in a two-roll mill at room temperature, achieving thickness reductions ranging from 10% to 70%. The presence of pits on the surface of the samples was assessed using optical microscopy. The onset of pitting corrosion was closely related to the strain level of the rolled plates. There was a steep decrease of resistance to localized attack as the thickness reduction increased.