某热电厂高温过热器蛇形管开裂原因分析  

Cracking Reason Analysis of High Temperature Superheater Coiled Pipes in a Thermal Power Plant

作　　者：石斌[1] 潘金平[1] 

机构地区：[1]嘉兴市特种设备检测院,嘉兴314001

出　　处：《理化检验（物理分册）》2010年第12期783-786,共4页Physical Testing and Chemical Analysis(Part A:Physical Testing)

基　　金：浙江省质量技术监督局资助项目(20100229)

摘　　要：某热电厂60%的高温过热器蛇形管在安装运行10 h后就发生了开裂失效。采用磁粉探伤检验、化学成分分析、硬度测试、金相检验、拉伸试验等多种手段分析了导致蛇形管早期开裂的原因。结果表明:开裂高温过热器蛇形管原材料由于合金元素钼分布不均匀而存在组织偏析,导致局部区域材料的塑性性能和抗腐蚀性能下降;在高温高压水蒸气和钢管自身强残余应力作用下,最终造成蛇形管由内壁向外壁发生了应力腐蚀开裂。In a thermal power plant,60%high temperature superheater colied pipes cracked after 10 h running.To find out the cracking reasons,means methods such as magnetic powder inspection,chemical compositions analysis,hardness test,metallographic examination and tensile test were applied.The results show that there was serious uneven distribution of Mo element which led to microstructure segregation in the material of the pipes.Thereafter it caused the plastic property and corrosion resistance of some regions decreased.Because of the combined effects of high temperature and high pressure vapor and high residual stress of the coiled piped,stress corrosion cracking occurred with cracks extending from inside wall to outside wall.

关 键 词：高温过热器蛇形管 应力腐蚀开裂 组织偏析 钼分布 

分 类 号：TG115[金属学及工艺—物理冶金]