Development of a reconstitution technique for Charpy impact specimens by surface-activated joining for reactor pressure vessel surveillance

Abstract The reconstitution technique by surface-activated joining (SAJ) has been investigated for the reuse of undeformed portions of tested Charpy impact specimens. SAJ can be achieved by the removal of surface contamination by rotating one of the specimens in a vacuum while applying modest frictional force. In this study, the temperature distribution during joining and hardness distribution after joining were measured. Charpy impact tests were then performed to evaluate the thermal and mechanical effects on Charpy specimens reconstituted by SAJ. The results showed that SAJ can be achieved with a hardened width of less than 1·5 mm, and on a width of less than 3 mm heating up above reactor operation temperatures, produced in either side of the joined interface. Charpy transition temperatures could be evaluated from the reconstituted Charpy specimens. It is concluded from comparison with other welding methods that the SAJ method is most suited for reconstituting irradiated surveillance specimens.