DEVELOPMENT OF A RECONSTITUTION TECHNIQUE FOR CHARPY IMPACT SPECIMENSBY SURFACE-ACTIVATED JOINING FOR REACTOR PRESSURE-VESSEL SURVEILLANCE

The reconstitution technique by surface-activated joining (SAJ) has be en investigated for the reuse of undeformed portions of tested Charpy impact specimens. SAJ can be achieved by the removal of surface contam ination by rotating one of the specimens in a vacuum while applying mo dest frictional force. In this study, the temperature distribution dur ing joining and hardness distribution after joining were measured. Cha rpy impact tests were then performed to evaluate the thermal and mecha nical effects on Charpy specimens reconstituted by SAJ. The results sh owed that SAJ can be achieved with a hardened width of less than 1.5 m m, 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 Cha rpy specimens. It is concluded from comparison with other welding meth ods that the SAJ method is most suited for reconstituting irradiated s urveillance specimens. (C) 1997 Elsevier Science Ltd.