核燃料组件用冷拉弹簧丝绕制断裂原因  

Fracture reason of cold drawn spring wire for nuclear fuel assembly

作　　者：何君 钟多军 李莎 罗林龄 HE Jun;ZHONG Duojun;LI Sha;LUO Linling(CNNC Jianzhong 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,宜宾644000

出　　处：《理化检验（物理分册）》2024年第10期71-76,共6页Physical Testing and Chemical Analysis(Part A:Physical Testing)

摘　　要：针对核燃料组件用XH77ТЮР合金弹簧丝在绕制过程中出现的断裂问题,采用宏观观察、扫描电镜分析、金相检验、化学成分分析、X射线衍射物相分析、缠绕性能试验、电子背散射衍射等方法对弹簧丝断裂原因进行分析。结果表明:冷拉弹簧丝绕制断裂模式为脆性断裂,断口附近显微组织粗糙,存在多处细微裂纹;弹簧丝表面存在加工硬化层,边缘区域的晶粒尺寸较小,内外部组织分布不均匀;弹簧丝表面存在微裂纹和划痕等表面缺陷,在弹簧绕制的拉应力作用下,表面硬化层和缺陷处形成裂纹并迅速扩展,导致弹簧发生脆性断裂。Aiming at the fracture problem of XH77TЮP alloy spring wire for nuclear fuel assembly in the winding process,the fracture causes of spring wire were analyzed by means of macroscopic observation,scanning electron microscope analysis,metallographic examination,chemical composition analysis,X-ray diffraction phase analysis,winding performance test and electron backscatter diffraction.The results show that the fracture mode of cold drawn spring wire was brittle fracture,the microstructure near the fracture was rough,and there were many fine cracks.There was a work hardening layer on the surface of the spring wire,the grain size in the edge region was small,and the internal and external microstructure distribution was uneven.There were surface defects such as micro cracks and scratches on the surface of the spring wire.Under the tensile stress of the spring winding,the surface hardening layer and the defects formed cracks and expanded rapidly,resulting in brittle fracture of the spring.

关 键 词：XH77ТЮР合金 弹簧丝 脆性断裂 裂纹 加工硬化 

分 类 号：TG115.2[金属学及工艺—物理冶金] TB31[金属学及工艺—金属学]