THE INFLUENCE OF INCLUSIONS ON THE CORROSION BEHAVIOR OF A 12 WT-PERCENT CHROMIUM STEEL

The effect of nonmetallic inclusions on the corrosion behavior of a 12 wt% Cr steel (3CR12) is reported. Potentiodynamic and potentiostatic tests were carried out on two commercial 3CR12 heats in order to examine the occurrence of micropitting associated with inclusions. Variations in inclusion populations give rise to notable differences in corrosion behavior. In particular, the dissolution of manganese sulfide inclusions led to the formation of micropits, a reduction in passive breakdown potentials, and an increase in the propensity for crevice formation. The presence of relatively insoluble titanium-rich sulfide and titanium carbonitride inclusions did not significantly affect the corrosion behavior of the steels.