Corrosion Resistance of Stainless Steels in Seawater

Abstract The resistance of commercial and laboratory produced stainless steels to crevice corrosion was evaluated by a 60 day exposure in filtered seawater at 25°C. The results in seawater were compared to laboratory tests in 10% FeCl3. Austenitic ferritic, and duplex stainless steels containing a minimum of 25%Cr-5%Mo, 27%Cr-3.4%Mo and 25%Cr-3.2%Mo, respectively, were found to be resistant to crevice corrosion in 25°C seawater. The austenitic stainless steels also required a minimum of 0.2%N. Significant reductions in either the chromium or molybdenum content resulted in substantial amounts of attack. There was a good correlation between the laboratory tests in 10% FeCl3 and the seawater test for the ferritic and duplex stainless steels but not for the austenitic grades.