Sulfate-reducing bacteria-assisted hydrogen-induced stress cracking of 2205 duplex stainless steels

The paper presents the results of a laboratory investigation of the microbiologically assisted hydrogen-induced stress cracking (HISC) of 2,205 duplex stainless steel (DSS). The testing of susceptibility toward HISC was performed with two different methods. Precharged in sulfate-reducing bacteria (SRB), inoculated medium samples were subjected to slow strain-rate testing in artificial seawater. In situ constant load tests were performed directly in SRB-inoculated medium under hydrogen charging at 70% of the ultimate tensile strength. Samples tested in the biotic (SRB) conditions showed a considerable loss of ductility as compared to those tested in sterile conditions. Quantitative characteristics of fracture surfaces indicated increased susceptibility to HISC of biotic samples, therefore, suggesting a role of SRB in promoting hydrogen damage of DSS.