Corrosion of stainless steel in sulphamic acid cleaning solutions

An investigation was conducted to characterize the corrosion behavior of Type 316L stainless steel (UNS S31 603) in a sulphamic acid (NH 2HSO3) cleaning solution. Corrosion and electrochernical testing confirmed that the leak failure of Type 316L stainless steel pipe spool removed from a NH2HSO3 cleaning system was caused by general corrosion, which involved hydrogen gas evolution as the dominant cathodic process. Furthermore, it was found that failure recurrence can likely be avoided by the use of an appropriate corrosion inhibitor. In this study a commercial inhibitor "A" was very effective in reducing the corrosion rate of both non-welded and welded Type 316L stainless steel in the acid cleaning condition under study.