The Albany Research Center has investigated the pitting corrosion resistance of experimental low-Cr stainless steels and several commercial stainless steels in chloride-containing aqueous and atmospheric environments. Previous research had shown the experimental alloys to be as corrosion resistant as commercial stainless steels in chloride-free acid environments. The alloys studied were Fe-8 Cr- 16Ni-5.5Si- ICU-(0-I )Mo, 304 SS, and 316 SS. These alloys were
examined by immersion and electrochemical tests in 3.5 wt. pct. NaCl and 6 wt. pct. FeCl3. Results of these tests showed that the addition of one weight percent Mo improved the pitting resistance of the low-Cr alloy and that the Mocontaining experimental alloy was as resistant to pitting as the commercial alloys. Electrochemical tests did, however, show the experimental alloys to be slightly less resistant to pitting than the commercial alloys. Because of these results, the low-Cr alloy with one weight percent Mo and 304 SS were exposed for one year to a marine atmospheric environment on the coast of Oregon. The marine atmospheric corrosion resistance of the low-Cr alloy was found to be comparable to that for type 304 stainless steel.
Keywords: Low-Cr, low chromium, stainless steel, localized corrosion, atmospheric corrosion, pitting, chloride.