Anti-corrosion Performance Regeneration in Aged Austenitic Stainless Steel by Precipitate Dissolution Below Critical Temperature Using Electropulsing

摘要

Precipitates that form at high temperatures detrimentally affect the mechanical properties and corrosion resistance of engineering structural materials. Different from the typical solution treatment, a method that incorporates electropulsing is proposed in this study. Electropulsing is applied to aged 316LN austenitic stainless steel, which undergoes the aging process at 650°C for 2 000 h, microstructure characterization by SEM and TEM shows that electropulsing can aid in dissolving precipitates. Both the immersion and electrochemical tests showed a positive shift at corrosion potential and a decrease in the corrosion current density caused by electropulsing, and the corrosion resistance was improved. The change in the system's free energy caused by the difference in the electrical conductivity between precipitates and matrix results in precipitate dissolution. This finding provides a technical reference for engineering applications, i.e., the on-line repair of properties in aged steels.