某电厂电站锅炉15Mo3低温过热器爆管失效分析  

Failure Analysis of 15Mo3 Tube Burst of Low-temperature Superheater in a Power Plant Boiler

作　　者：张新 张坤 刘巍栋 李梦阳 高大伟 杜双明 蔡文河 白泽洪 ZHANG Xin;ZHANG Kun;LIUWeidong;LI Mengyang;GAO Dawei;DU Shuangming;CAIWenhe;BAI Zehong(Institute of Thermal Power Generation Technology,China Datang Coporation Science and Technology Research Institute,Beijing 100040,China;Datang Northeast Electric Power Test&Research Institute,China Datang Coporation Science and Technology Research Institute,Changchun 130012,China;Datang Northwest Electric Power Test&Research Institute,China Datang Coporation Science and Technology Research Institute,Xi'an 710065,China;Equipment Department,Hebei Datang International Zhangjiakou Power Generation Co.,Ltd.,Zhangjiakou 075131,China)

机构地区：[1]中国大唐集团科学技术研究院火力发电技术研究院,北京100040 [2]中国大唐集团科学技术研究院大唐东北电力试验研究院,长春130012 [3]中国大唐集团科学技术研究院大唐西北电力试验研究院,西安710065 [4]河北大唐国际张家口发电有限责任公司,张家口075131

出　　处：《腐蚀科学与防护技术》2019年第6期650-658,共9页Corrosion Science and Protection Technology

摘　　要：对大型电站锅炉15Mo3低温过热器爆管进行失效分析,采用宏观分析、直读光谱仪、金相显微镜、扫描电镜、布氏硬度计、万能试验机等对低温过热器爆管失效进行化学成分、微观组织、氧化、硬度及拉伸性能分析。结果表明:爆管的化学成分满足DIN17155标准的要求;管样的抗拉强度、屈服强度、伸长率和布氏硬度分别达到459 MPa、355 MPa、30.02%和150,满足了DIN17155标准对15Mo3的要求;爆管主要原因是15Mo3材质低温过热器发生腐蚀使管壁不断减薄,最终由于强度不足而发生爆管;管壁腐蚀区域主要位于尿素喷枪下方,腐蚀的主要原因是由于尿素喷枪雾化效果不良,尿素滴落,高温下与金属反应,导致管壁持续减薄;同时对15Mo3低温过热器的安全稳定运行提出了相关的建议。Failure analysis of the burst 15Mo3 tube for low-temperature superheater in large utility boilers is carried out by means of macroscopic observation,direct reading spectrometer,metallographic microscope,scanning electron microscopy,Brinell hardness tester and universal testing machine.The results show that the chemical composition of the burst tube meets the requirements of DIN17155 standard,and the tensile strength,yield strength,elongation and Brinell hardness of the tube samples reach 459 MPa,355 MPa,30.02%and 150,respectively,which meet the requirements of DIN17155 standard for 15Mo3 steel.The main reason for tube burst is that the wall of 15Mo3 steel tube underwent thinning continuously due to corrosion,and the excessive local thinning finally will cause the tube burst.The corrosion sites of the tube wall is mainly located below the urea spray gun.The main cause of corrosion is that the urea spray gun has poor atomization effect,urea drops onto and reacts with the outer wall of the relevant steel tube at high temperature,which results in the continuous local thinning of the tube wall.At the same time,some suggestions for safe and stable operation of the low-temperature superheater are put forward.

关 键 词：低温过热器 爆管 失效分析 15Mo3 

分 类 号：TG174[金属学及工艺—金属表面处理]