Polarization Behavior of Austenitic and Duplex Stainless Steels in the Double Loop Reactivation Test

Abstract

Abstract The corrosion behavior of AISI 304L and 308L stainless steels (SSs) in electro-potentiostatic reactivation (EPR) tests has been investigated using the double loop technique. The AISI 304L SS was tested in the fully austenitic and in the duplex (γ + δ) condition; the AISI 308L SS was in the form of a submerged arc weld metal having a duplex microstructure. The materials were aged at 700 C to induce phase transformation and sensitization and EPR tests were conducted both before and after the aging treatments. In tests on unaged material, single peaks in the corrosion current were detected in both the activation and reactivation potential scans (Ia and Ir respectively), and in the aged austenitic AISI 304L SS, the effects of sensitization were manifested, as expected, by an increase in both Ir and the ratio Ir to Ia. In tests on aged duplex materials, the increase in the height of the previously identified reactivation peak was accompanied by the appearance of a second reactivation peak, which coinc...