Interpretation of Electrochemical Potentiokinetic Reactivation data in the presence of sulphide/oxysulphide inclusions in 316LN stainless steel

This paper presents the Electrochemical Potentiokinetic Reactivation (EPR) parameters obtained for non-sensitised 316LN stainless steel containing sulphide/oxysulphide inclusions. Even in the absence of sensitization, reactivation peaks were obtained in single loop and double loop EPR experiments for longitudinal and cross transverse sections. Using Laser Raman Spectroscope, Raman maps of Cr (VI) oxide were obtained around the inclusions. It was inferred that the reactivation peak is due to dissolution of sulphide inclusions and chromium depleted zones arising around chromium segregated flow lines. The need to interpret EPR parameters carefully in the presence of sulphide inclusions is emphasised.

► Single loop and double loop EPR studies for SS containing inclusions.
► Non sensitised condition reactivation peak observed.
► Raman maps of Cr (VI) oxide on and around inclusions.
► Reactivation peak is due to dissolution of sulphide inclusions.
► Reactivation peak is due to Cr depleted zones arising around Cr segregated flow lines.