Super duplex and super austenitic stainless steels are often specified for aggressive chloride environments including those found at desalination plants due to the corrosion resistance of these classes of materials to chloride environments. In seawater reserve osmosis desalination plants the comparatively higher strength of the super duplex stainless steel (SDSS) often results in preferential choice of SDSS. In general these materials show high resistance to corrosion, though in specific situations, crevice corrosion has been found to occur in a relatively short time frame.
This paper reviews the factors that contribute to crevice corrosion of stainless steel in chloride environments, and the predicted behavior of SDSS in crevice conditions. This information will be combined with the visual observations of the crevice corrosion identified on SDSS flanges exposed to a high chloride environment within a SWRO desalination plant.