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

Abstract

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.

Influence of Aging Treatment on the Microstructure Evolution and Mechanical Properties of 316H Weld Metals with Different C Contents

“…316 austenitic stainless steel is widely used in the manufacture of nuclear reactor components owing to its excellent comprehensive properties, such as main vessel, support assembly, core barrel, etc. [7][8][9][10][11][12] During the fusion welding of austenitic stainless steel, the tendency of hot cracking tends to occur when the structural restraint is too large. In order to prevent cracking in the welding process, it is usually desirable to form a certain amount of δ -ferrite in the weld microstructure.…”