Dislocation regulation through pulsed electric current making degraded pressure vessel steel’s performance regeneration

A508–3 steel used for reactor pressure vessels may form microstructural defects such as dislocations during early operation, leading to an increase in the ductile brittle transition temperature of the material and thus shortening the service life of the pressure vessel. Based on the limitations of traditional annealing repair methods, which affect the expected performance due to changes in the microstructure of the material matrix caused by long-term high-temperature treatment, this study proposes the use of pulsed electric current treatment technology for multiple cycles to repair pressure vessels with degraded performance. At 85 °C, after pulse current treatment, the ductile brittle transition temperature of A508–3 steel subjected to secondary aging was restored to 78.6 % of the original unaged sample. The ductile brittle transition temperature of the aged sample after the second pulse current cycle repair (-106.9 °C) is close to that after the first pulse current treatment (-108.6 °C), indicating that the aging rate of the sample is delayed after pulse current repair. Under the action of pulsed current, electronic wind promotes the slip and annihilation of dislocations, thereby regenerating the properties of aged pressure vessel steel, providing a new way to extend the service life of pressure vessels.