Effect of Strength Mis-Matching on Fracture Behavior for Nuclear Pressure Vessel Steel A508-Ⅲ Welded Joints

The effect of strength mis-matching on the fracture behavior of A508 Ⅲ welded joints was analyzed by fracture mechanics test and FE calculation,the fracture behavior for HAZ was emphasized especially.It has been shown that the opening stress and stress triaxiality in the vicinity of crack tip are reduced for weld crack specimen,and increased for HAZ-crack specimen,if the over matching weld is used.In other words,over matching could improve the fracture resistance for weld crack specimen,and deteriorate for HAZ crack specimen.This tendency was confirmed by the test result.