CF3燃料组件下管座钎焊工艺及缺陷控制  

Study on Brazing Process and Defects Control of CF3 Fuel Assembly Bottom Nozzle

作　　者：李莎 袁野 钟多军 LI Sha;YUAN Ye;ZHONG Duojun(CNNC Jian Zhong Nuclear Fuel Co.,Ltd.,Yibin 644000,China)

机构地区：[1]中核建中核燃料元件有限公司,四川宜宾644000

出　　处：《电焊机》2022年第12期77-84,共8页Electric Welding Machine

摘　　要：CF3型先进压水堆燃料组件下管座为空间曲面结构,需采用真空钎焊工艺组装焊接。针对304L不锈钢母材和BNi-7钎料的特点,确定了钎焊工艺曲线,并测试分析钎焊循环次数对母材冲击性能、室温及高温抗拉强度,以及钎缝剪切强度和微观组织的影响。结果表明:即使经过四次钎焊循环工艺,母材和钎缝的力学性能及微观组织也没有受到明显不利影响。为提高生产效率和降低能耗,推荐采用二次钎焊循环组装并可选第三次钎焊循环补焊的工艺。通过调整配合间隙,改进下管座结构件的结构、导向管座孔加工工艺和双叶片结构,避免了流道堵塞、未钎到、未钎满等缺陷,提高了产品成品率和生产效率。The bottom nozzle of CF3 advanced PWR fuel assembly is a creative space curved structure, which needs to be assembled and brazed by the vacuum brazing technology. According to the characteristics of 304L stainless steel base metal and BNi-7 filler metal, the brazing process curve was determined. Then the effect of brazing cycles on the impact properties,room temperature and high temperature tensile strength of the base metal, as well as the shear strength and microstructure of the brazed joints were tested and analyzed. The results show that even after four-stage brazing cycles, the mechanical properties and microstructure of the base metal and brazed joints are not significantly adversely affected. In order to improve production efficiency and reduce energy consumption, it is recommended to use two-stage brazing cycles assembly, plus the optional third brazing cycle repair brazing process. And also, through adjusting the joint clearance, improving the structure of the bottom nozzle, the machining process of the guiding tube hole, and the structure of the double blade, the defects such as flow channel blockage, lack of filler metal, and so on, are avoided. Eventually, the product yield is increased and production efficiency are raised.

关 键 词：CF3压水堆 燃料组件 力学性能 微观组织 钎焊循环工艺 缺陷控制 

分 类 号：TG454[金属学及工艺—焊接]