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

Abstract

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 (ER,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 ER,CREV values were obtained for DSS 2205 and LDSS 2002. These abnormal ER,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 ≈ 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.