A discussion on evaluation criteria for crevice corrosion of various stainless steels

In this study, crevice corrosion performances of a newly developed LDSS 2002 and three commercial stainless steels (AISI 304, AISI 316L and DSS 2205) were investigated and discussed. Crevice repassivation potential (E-R,E-CREV), which was measured by the potentiodynamic-galvanostatic-potentiodynamic (PD-GS-PD) test, was applicable to crevice corrosion evaluation of 304 and 316L stainless steels. However, much lower E-R,E-CREV values were obtained for DSS 2205 and LDSS 2002. These abnormal E-R,E-CREV values for duplex stainless steels may be related to the selective attack of the less corrosion-resistant phase, the lower corrosion potential in the crevice-like solution, and more crevice corrosion sites in the PD-GS-PD test. A critical chloride concentration of crevice corrosion (CCCCREV) measurement was introduced for crevice corrosion evaluation of various stainless steels. The derived CCCCREV was proved to be a valid criterion for crevice corrosion evaluation of both the austenitic and duplex stainless steels. An order of crevice corrosion resistance of AISI 304 approximate to LDSS 2002 < AISI 316L < DSS 2205 was suggested, which agreed well with the orders of pitting resistance equivalent number and critical crevice index of the less corrosion-resistant phase in each material. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.