Residual stress and deformation in a welded joint will significantly reduce its service life, and thus the analysis and regulation of residual stresses are very important. In this paper, a SYSWELD software was used to numerically simulate the temperature field, residual stress field, and the welding deformation during welding with and without a Cu interlayer. Thermocouples were used to measure the thermal cycle curves, and X-ray diffraction (XRD) was used to measure the residual stresses of the joints. The results show that the addition of a Cu interlayer does not significantly change the temperature field, and that the high temperature region on the niobium side is wider. In addition, the peak temperature in the centre of the welds and the temperature gradient perpendicular to the weld are greatly reduced by a Cu interlayer. Furthermore, a Cu interlayer contributes to a certain increase in both transverse and longitudinal residual stresses. Because the weld involves three different materials, steel, niobium, and Cu, the residual stresses in the welds are more complex. The simulation of the welding deformation shows that the transverse shrinkage in the thickness direction can be homogenized by the Cu interlayer, which leads to a significant reduction in deformation.

焊接接头的残余应力和变形会显着降低其使用寿命，因此残余应力的分析和调节非常重要。本文采用SYSWELD软件对有和无Cu夹层焊接过程中的温度场、残余应力场和焊接变形进行数值模拟。热电偶用于测量热循环曲线，X射线衍射（XRD）用于测量接头的残余应力。结果表明，Cu夹层的加入不会显着改变温度场，铌侧的高温区域更宽。此外，焊缝中心的峰值温度和垂直于焊缝的温度梯度因铜夹层而大大降低。此外，Cu 夹层有助于增加横向和纵向残余应力。由于焊缝涉及钢、铌和铜三种不同材料，因此焊缝中的残余应力较为复杂。焊接变形模拟表明，Cu夹层可以使厚度方向的横向收缩均匀化，从而导致变形显着减少。