Comparison of 304 and 316 stainless steel microbiologically influenced corrosion by an anaerobic oilfield biofilm consortium

Abstract

Abstract Stainless steel (SS) has wide applications in oilfields because of their outstanding corrosion resistance. However, SS is susceptible to localized MIC (microbiologically influenced corrosion). In this study, the MIC caused by an oilfield mixed-culture consortium (labelled as Consortium II) in enriched artificial seawater against commonly utilized 304 SS and 316 SS was evaluated. Sessile cell count results showed that Consortium II had better growth on 304 SS surface than on 316 SS with 79% more sulfate reducing bacteria (SRB) and 37% more acid producing bacteria (APB). Pitting corrosion was observed. The corrosion resistance (Rp) from linear polarization resistance (LPR) of 316 SS was two times as much as that for 304 SS during the 14-day incubation, while the corrosion current density (icorr) of 304 SS was 101 higher than that for 316 SS (2.19 µA/cm2 vs. 0.19 µA/cm2) at the end of the incubation. These results suggested that 316 SS was considerably more resistant to MIC by the oilfield biofilm than 304 SS.