Determination of susceptibility to intergranular corrosion and electrochemical reactivation behaviour of AISI 316L type stainless steel

In this study, double loop electrochemical potentiokinetic reactivation (DLEPR) test was applied to determine the degree of sensitization in 316L type stainless steel, where obtained results were correlated with revealed microstructures after oxalic acid test and weight loss measurements of Streicher and Huey acid tests. Best agreement was provided with test parameters which are 1 M H2SO4 and 0.005 M KSCN at 0.833 mV/s scan rate at 30 °C. Specimens were classified structurally as absence of chromium carbides – step, no single grain completely surrounded by carbides – dual and one or more grain completely surrounded by carbides – ditch, in the as-etched structure, if the Ir:Ia (×100) ratios were obtained to be between 0 and 0.2, 0.2 and 5.0 and 5.0 and higher, respectively. It was also found that at high KSCN concentrations, reactivation current profile skewed to higher potentials where this was attributed the formation of metastable pits, during the anodic scan of the test procedure.