Corrosion of SUS 310 Steels at 600-800°C in N2/H2O/H2S Gases

Abstract

SUS 310 stainless steels were corroded at 600, 700 and 800°C for up to 30 h in 1 atm of N2/H2O/H2S-mixed gas. The formed scales consisted primarily of (Fe0.5Ni0.5)0.96S, FeNiS2, and FeCr2S4. They were fragile, porous, and susceptible to spallation. During corrosion, Fe, Ni, and Mn diffused outward, while sulfur and a lesser amount of oxygen diffused inward. The diffusion of Cr and Si was not conspicuous. The formation of sulfide scales and the presence of hydrogen and water vapor in the mixed gases made SUS 310 corrode fast.