反应堆压力容器内部大尺寸环形异种金属焊缝残余应力分布研究

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

获得反应堆压力容器内部大尺寸环形异种金属焊缝残余应力分布可为反应堆压力容器结构设计和制造工艺优化提供指导,通过设计和制造能够代表产品焊接结构形式的镍基合金和低合金钢异种金属焊接结构模拟件,采用轮廓法测试焊接结构模拟件内部纵向残余应力,采用有限元法模拟计算焊接结构模拟件横向和纵向残余应力,获得了整个异种金属焊接接头残余应力分布特征。结果表明:焊缝区域内部纵向残余应力为拉伸应力,峰值应力达到500 MPa左右,并且表层应力大于内部应力,峰值应力出现在距下表面3 mm和24 mm位置;横向残余应力在焊缝区域从上表面到下表面的分布为拉应力-压应力-拉应力,压缩横向残余应力峰值达到−300 MPa,出现在距下表面约18 mm位置。本文研究可为焊接结构设计提供理论指导。

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.