A new approach for DL-EPR testing of thermo-mechanically processed austenitic stainless steel

Highlights: → A new approach has been introduced to obtain the degree of sensitisation (DOS). → This new approach is more accurate than standard methods. → This may be used to compare the DOS of microstructures of different characteristics. → The length of attacked boundaries is described by cluster compactness parameter. - Abstract: Standard test methods such as the electrochemical potentiokinetic reactivation test (EPR) and double-loop EPR test (DL-EPR) are commonly used to characterise sensitisation behaviour in austenitic stainless steels and nickel-based alloys. In this study, the DL-EPR test is augmented by large-area image analysis (IA) to characterise and quantify the networks of attacked grain boundaries. A new analysis approach that is based on a grain boundary cluster parameter is proposed to describe the network of corrosion susceptible grain boundaries, which may be estimated from electron backscatter diffraction (EBSD) data. This method may provide a better assessment of the relative DOS of different heats of austenitic stainless steels.