Effect of Post Weld Heat Treatment on Toughness of Base Metal of Nuclear Reactor Pressure Vessel Steel A533B

The effect of post weld heat treatment (PWHT) on the toughness of nuclear reactor pressure vessel steel was investigated.Fracture toughness (K JC) and Charpy impact toughness (KVC) were obtained at different temperatures for quenched-tempered (QT) and PWHT A533B steel plates,respectively.The results show that PWHT increases the ductile-brittle transition temperature,and decreases the K JC and KVC.By using SEM and Electron probe micro-analyzer (EPMA),it is found that the size of the precipitation phases increased and molybdenum precipitated during PWHT respectively.The relationship between the size of the precipitation phases and the fracture toughness are analyzed and the influence of microstructure is also briefly discussed.