Study of Residual Stress Distribution of Large Ring-type Dissimilar Metal Weld in Reactor Pressure Vessel

To obtain the residual stress distribution of the large ring-type dissimilar metal weld in the reactor pressure vessel(RPV), and guide the structural design and manufacturing process optimization of the reactor pressure vessel, the dissimilar metal welding structure simulators of nickel base alloy and low alloy steel, which can represent the welding structure form of products, are designed and manufactured. The longitudinal residual stress in the welding structure simulators is tested by contour method, and the transverse and longitudinal residual stress of the welding structure simulators are simulated and calculated by finite element method. The residual stress distribution characteristics of the whole dissimilar metal welding joint are obtained. The results show that the longitudinal residual stress in the weld area is tensile stress, the peak stress reaches about 500 MPa, and the surface stress is greater than the internal stress, and the peak stress occurs at 3 mm and 24 mm from the lower surface; The distribution trend of transverse residual stress in the weld area from the upper surface to the lower surface is tensile stress - compressive Stress - tensile stress. The peak value of compressive transverse residual stress reaches −300 MPa and appears about 18 mm away from the lower surface. The research in this paper can provide theoretical guidance for the design of welding structures. © 2022, Editorial Board of Journal of Nuclear Power Engineering. All right reserved.