External Stress Corrosion Cracking (ESCC) due to chlorides sometimes occurs in austenitic stainless steel equipment or piping that is not thermally insulated and located near a seashore. To investigate such
behavior, a 15-year exposure test of austenitic stainless steels was performed at two sites in Japan. Stainless steels coated with various coating systems were also tested. Intergranular SCC was observed only in the fillet welds of sensitized Type 304 stainless steel. Transgranular SCC initiated from crevices was observed in solution-treated Types 304/304L and sensitized Type 304L stainless steels, even at ambient temperature. No cracks were found in Types 316/316L stainless steels. Coatings could not fully prevent ESCC for long-term exposure without repair of the coating.
Key words: External Stress Corrosion Cracking (ESCC), Austenitic Stainless Steel, Exposure Test