核岛冷却系统铜-不锈钢真空扩散焊焊接工艺设计和性能研究

Vacuum diffusion welding technology design and performance study of Cu-stainless steel in nuclear island cooling system

铜-不锈钢管复合构件由于结构与性能的优势互补,在核反应堆的设备冷却系统中发挥着重要的作用。针对核岛冷却系统铜-不锈钢真空扩散焊接工艺复杂、难度大,进行了焊接工艺的设计和性能研究方案的制定,并进行性能评价和微观组织观察,利于解决目前焊接中存在的问题。试验采用添加单质Ni作镀膜中间层的方法,在一定温度、压力以及真空度下进行铜与不锈钢的真空扩散焊接,通过剪切试验和硬度测量评价铜-不锈钢接头的力学性能,利用ZEISS显微镜、SEM扫描电镜、EDS能谱仪分析接头的微观形貌和扩散结合过程。通过焊接接头的随机取样分析比较,发现本次扩散焊接试验得到的焊接接头仍存在结合不充分、性能不均衡等缺陷,焊接工艺有待进一步优化。

Due to the complementary advantages of structure and performance,copper-stainless steel pipe composite components play an important role in the cooling system of nuclear reactor equipment. In view of the complex and difficult vacuum diffusion welding process of Cu-stainless steel in the nuclear island cooling system,the welding process is designed and the formulation of the performance study scheme,the performance evaluation and microstructure observation are carried out,which is helpful to solve the existing problems in welding. In this experiment,the method of adding Ni as the intermediate layer of coating is adopted. The vacuum diffusion welding of copper and stainless steel is carried out at a certain temperature, pressure and vacuum degree. The mechanical properties of the cop-stainless steel joint are evaluated by shear test and hardness measurement. The microstructure and diffusion bonding process of the joint are analyzed by ZEISS microscope,SEM scanning electron microscope and EDS. Through the random sampling analysis and comparison of the welded joints,it is found that the welded joints obtained by the diffusion welding test still have defects such as insufficient joint and unbalanced performance,and the welding process needs to be further optimized.