Effect of austenite stability on the pitting corrosion resistance of cold worked stainless steels

Abstract

The influence of cold rolling on the pitting resistance of stainless steels is investigated with respect to the austenite stability. A maximum in pitting initiation frequency for 20% reduction is confirmed whatever the austenite stability, but the value of this maximum fairly correlates to the amount of deformation-induced martensite. A direct influence of dislocations piling-up and an indirect role of martensite as a pile-up stabilizer is postulated. In the potentiostatic regime, cold work is shown to lower the repassivation ability and to increase the number of stable pits. Then, addition of alloying elements (such as copper) affects the pitting resistance not only for chemical but also for mechanical reasons (such as their effect on the staking fault energy and austenite stability), confirming the decisive role of microstructure in pitting corrosion of industrial alloys.