Comparative corrosion behaviour of austenitic 316L and duplex 2205 stainless steels: microstructure and property evolution at highly partial pressure of H₂S

Abstract

This study extensively compares the corrosion behavior of austenitic 316L and Duplex 2205 stainlesssteels at different partial pressures of H 2 S gases. The results showed that the corrosion rate of both steels at 3 bar H 2 S showed the highest rate among those parameter setups. 316L steel is dominated by both uniform and pitting corrosion under H 2 S-containing conditions due to the dissolution of Cr present on the alloy surface. According to the cross-sectional analysis, a Cr enrichment layer formed at 0 bar H 2 S in both steels. After depletion of the Cr compound in the passive film of both steels, Ni was enriched in the outer layer at 3 bar H 2 S, forming Ni oxide/sulphide compounds within the passive layer. At 15 bar H 2 S, Mo was enriched in 316L steel, while Fe and Cr were enriched on the 2205 steel surface. Thus, a kinetic study of the chemical composition of both steels was discussed.