熔覆金属覆盖的水冷壁泄漏原因分析  

Leakage Causes Analysis of the Water Wall Coveredby Cladding Metal

作　　者：杨毅 柯浩 YANG Yi;KE Hao(Huadian Electric Power Research Institute Co.,Ltd.,Hangzhou 310030,China)

机构地区：[1]华电电力科学研究院有限公司,浙江杭州310030

出　　处：《锅炉技术》2023年第4期47-51,63,共6页Boiler Technology

摘　　要：某300 MW循环流化床锅炉水冷壁在防磨熔覆金属覆盖处发生泄漏,为分析泄漏原因,进行了外观检查、光谱分析、壁厚检测、渗透检测、金相检验和拉伸试验。结果表明:由于受防磨梁限制,只能采用手工等离子熔覆防磨处理,熔覆工艺参数控制不当,导致熔覆层残余应力过大;新更换的水冷壁短管承受较大的拘束应力;在残余应力和拘束应力共同作用下,在熔覆层产生大量横向裂纹。在长期高温高压运行过程中,残余应力和拘束应力最大部位的裂纹扩展较快,贯穿管壁而泄漏。结合生产实际情况,提出了一些减少熔覆层开裂的措施及建议。The water wall tube of a 300 MW circulating fluidized bed boiler leaked in the metal cladding area.In order to analyze the cause of leakage,visual examination,spectral analysis,wall thickness measurement,penetrant testing,metallographic inspection and tensile testing were carried out.The results show that because of the anti-wear beam,plasma cladding anti-wear treatment could only be done manually,and improper control of cladding process parameters leaded to excessive residual stress in cladding layer.In addition,the newly replaced short water wall tube beared greater constraint stress.Under the combined action of residual stress and constraint stress,a large number of transverse cracks occured in the cladding layer.In the process of long-term high temperature and high pressure operation,the cracks with the largest residual stress and constraint stress spreaded faster and leaked through the tube wall.According to the actual production situation,some measures and suggestions to reduce the cracks in cladding layer are put forward.

关 键 词：循环流化床 水冷壁 熔覆 残余应力 拘束应力 裂纹 泄漏 

分 类 号：TG178[金属学及工艺—金属表面处理]