Temperature Dependence of Corrosion of Ferritic/Martensitic and Austenitic Steels in Liquid Lead-Bismuth Eutectic

Abstract

Corrosion tests of ferritic/martensitic (F/M), austenitic stainless and Si-added austenitic steels were conducted at 450 to 600°C for 2000 h or 3000 h in oxygen-saturated lead-bismuth eutectic (LBE) to clarify temperature effect on corrosion behavior. While the corrosion depth is small at 450°C because of oxide film formation with low growth rate, it increases at 500°C due to additional grain boundary corrosion/internal oxidation and node formation. At 550°C, extensive grain boundary corrosion/internal oxidation is observed in F/M steels. Ferritization characterized by selective dissolution of Ni and Cr, and LBE penetration occurs in austenitic stainless steels, JPCA and 316SS. Corrosion attack becomes very severe for most steels at 600°C. LBE penetration follows grain boundary corrosion/internal oxidation in F/M steels and ferritization advances deeply in JPCA and 316SS. The compound corrosion layer of oxidation, dissolution and LBE penetration often peels off. Addition of Si to austenitic steels is useful to improve corrosion resistance.