Enhancement of the resistance to localized corrosion of type 304 borated stainless steels through hot rolling

The microstructures of Febalance-18Cr-12Ni-1.5Mn-0.07C (in wt%) alloys containing 0.2–1.76 wt% B were controlled through hot rolling of 60% and 96%. It was found that refining the microstructure through additional hot rolling helped to form a stable passive film and accelerate passivation. Passive film formed on the 96% hot-rolled BSS exhibited higher electrical resistant than that of the 60% hot-rolled BSS, and Cr-enriched passive film was formed on the 96% hot-rolled BSS. As a result, refining the microstructure increased Epit and Erp, and reduced metastable pit events and passive current density.