核级阀门堆焊密封面裂纹原因分析  

Cause Analysis of Cracks on Surfacing Sealing Surface of Nuclear Grade Valve

作　　者：孙奇[1,2,3] 范清华 焦咏翔 赵祥路 李天澍 黄治冶 邓德伟 SUN Qi;FAN Qinghua;JIAO Yongxiang;ZHAO Xianglu;LI Tianshu;HUANG Zhiye;DENG Dewei(School of Materials Science and Engineering,Dalian University of Technology,Dalian 116024,China;R&D Division of Shenyang Blower Works Group Corporation and Dalian University of Technology,Dalian 116024,China;Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province),Dalian 116024,China)

机构地区：[1]大连理工大学材料科学与工程学院,辽宁大连116024 [2]沈阳鼓风机集团股份有限公司-沈鼓大工研究院,辽宁大连116024 [3]辽宁省凝固控制与数字化制备技术重点实验室,辽宁大连116024

出　　处：《热加工工艺》2021年第17期157-162,共6页Hot Working Technology

基　　金：辽宁重大装备制造协同创新中心基金项目(DUT2017031);高端控制阀产业技术协同创新中心基金项目(2018WZ003);国家973项目(2011CB013402);辽宁省自然科学基金项目(2014028002);辽宁省科技创新重大专项项目(201303002)。

摘　　要：某核级阀门在核电站现场存放两年后,安装调试过程中发现阀门密封面泄漏的问题。采用液体渗透剂、荧光光谱仪、扫描电镜、EDS能谱仪、金相显微镜、显微硬度计、残余应力测试仪等设备和方法对失效的阀门进行测试。结果表明:阀体密封面堆焊的硬质合金存在孔洞;断面处发现大量韧窝,属于韧性断裂;硬质合金层的残余应力处于比较高的水平,阀门在核电站现场长期存放,残余应力逐渐在孔洞处形成应力集中萌生裂纹,裂纹沿着堆焊层内部的孔洞扩展,导致阀体密封面密封失效。After two years of storage of a nuclear-grade valve at nuclear power plant site, the leakage problem of sealing surface was found during the installation and commissioning process. The failed valve was analyzed by using liquid penetration, fluorescence spectrometer, scanning electron microscope, EDS energy spectrometer, metallographic microscope,microhardness tester, residual stress tester and other equipment and methods. The results show that the hard alloy sufaced on the sealing surface of the valve body has holes, and a large number of dimples are found at the fracture. The residual stress on the sealing surface is relatively high. During a long time storage of the valve at nuclear power plant, residual stress gradually concentrates and crack initiates at the hole, and the crack propagates along the hole in the surfacing layer, resulting in the failure of the sealing surface of the valve body.

关 键 词：核级阀门 硬质合金 裂纹 堆焊 失效分析 气孔 

分 类 号：TG441.7[金属学及工艺—焊接]