Evaluation of intergranular corrosion susceptibility of UNS S31803 duplex stainless steel with an optimized double loop electrochemical potentiokinetic reactivation method

Abstract

Abstract In this study, an optimized double loop electrochemical potentiokinetic reactivation (DL-EPR) test was applied to evaluate the degree of intergranular corrosion (IGC) susceptibility of duplex stainless steel UNS S31803. The measurement in a solution of 2 M H 2 SO 4 + 1 M HCl at 30 °C with a scan rate of 1.66 mV s −1 can successfully be used to analyze the interactions between precipitation, chromium depletion, and IGC sensitization of the UNS S31803 steel, which was aged between 30 min and 48 h at 800 °C. To gain an insight into the phase transition, the specimens were analyzed by scanning electron microscopy (SEM) and electron dispersive X-ray spectroscopy (EDX). The results indicated healing due to re-diffusion of Cr and Mo from the σ phase to the γ 2 phase.