某电站锅炉水冷壁管泄漏原因  

Causes of water wall tube leakage of a power station boiler

作　　者：周嘉炜 封小亮 刘课秀 ZHOU Jiawei;FENG Xiaoliang;LIU Kexiu(Guangzhou Academy of Special Equipment Inspection&Testing,Guangzhou 510663,China)

机构地区：[1]广州特种设备检测研究院,广州510663

出　　处：《理化检验(物理分册)》2025年第1期66-71,共6页Physical Testing and Chemical Analysis(Part A:Physical Testing)

基　　金：广州市市场监督管理局科技项目(2023KJ12)。

摘　　要：采用宏观观察、化学成分分析、力学性能测试、金相检验、扫描电镜及能谱分析、X射线衍射物相分析等方法对某电厂锅炉水冷壁管的泄漏原因进行分析。结果表明:锅炉在运行过程中,热载荷、吹灰、焊接、水垢、管壁金属减薄等因素使水冷壁管内壁出现局部氧化膜受损,受损部位基体金属与介质中的铜离子发生电化学腐蚀,导致水冷壁管发生腐蚀减薄,局部出现铜聚集并形成垢层;水冷壁内壁垢层的传热性差,局部形成异常高温高压环境,使钢管内壁金属发生垢下氢腐蚀,造成钢管组织脱碳、晶界开裂,并逐渐扩展为宏观裂纹,降低了水冷壁管的局部力学性能,最终导致水冷壁管发生泄漏事故。Macroscopic observation,chemical composition analysis,mechanical property test,metallographic examination,scanning electron microscope and energy spectrum analysis,X-ray diffraction phase analysis were used to analyze the leakage causes of boiler water wall tubes in a power plant.The results show that during the operation of the boiler,heat load,soot blowing,welding,scale,wall metal thinning and other factors damaged the local oxide film on the inner wall of the water wall tube.The electrochemical corrosion of the matrix metal and the copper ion in the medium led to the corrosion thinning of the water wall tube,copper agglomeration and formation of scale layer appeared locally.The heat transfer of the scale layer on the inner wall of the water wall was poor,and an abnormal high temperature and high pressure environment was formed locally,which caused hydrogen corrosion under the scale on the inner wall of the steel pipe,resulting in decarburization of the steel pipe structure,grain boundary cracking and gradual expansion into macro cracks,reducing the local mechanical properties of the water wall pipe,and eventually leading to leakage accidents of the water wall pipe.

关 键 词：水冷壁管 电化学腐蚀 氢腐蚀 20G钢 铜元素 垢层 

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]