某电厂水冷壁管泄漏原因分析  

Leakage Causes Analysis of Water Wall-cooled Tube in one Power Plant

作　　者：王科芳 WANG Kefang(Fujian Datang International Ningde Power Generation Co.,Ltd.,Ningde 352000,China)

机构地区：[1]福建大唐国际宁德发电有限责任公司,福建宁德352000

出　　处：《锅炉制造》2025年第1期49-52,共4页Boiler Manufacturing

摘　　要：对某电厂泄漏水冷壁管取样进行宏观检验、光谱检验、显微组织分析、硬度检验、力学性能试验。结果表明:爆管首爆口张开较大,爆口边缘有明显变形减薄;首爆管的化学成分符合标准要求;首爆管迎烟气侧组织为铁素体+长条状珠光体,珠光体未见分散特征,为相变组织,背烟气侧组织为铁素体+珠光体,老化3级,迎烟气侧硬度值高于背烟气侧。水冷壁管泄漏原因为管子短期过热使得迎烟气侧温度超过Ac_3温度,从而造成管子迎烟气侧组织发生相变,力学性能下降,在蒸汽内压力作用下,温度较高、性能下降更多的迎烟气侧产生鼓胀变形,管壁变薄,继而发生爆管。Macroscopic inspection,spectral inspection,microstructure analysis,hardness testing,and mechanical performance testing were conducted on samples of leaking water-cooled wall tube in a power plant.The burst is large and there is obvious deformation and thinning at the edge of the burst.The chemical composition of the first explosive tube meets the standard requirements.The structure on the facing smoke side of the first blast tube is composed of ferrite and elongated pearlite,with no dispersed characteristics of pearlite,which is a phase transformed microstructure.The structure on the back smoke side is composed of ferrite and pearlite too,aged at level 3.The hardness value on the facing smoke side is higher than that on the back smoke side.The reason for the leakage of the water-cooled wall tube is that the tube overheats for a short period of time,causing the temperature on the upstream side of the tube to exceed the Ac 3 temperature,resulting in a phase transition of the microstructure on the upstream side of the tube and a decrease in mechanical properties.Under the action of steam internal pressure,the upstream side of the tube with higher temperature and more decreased performance undergoes bulging and deformation,causing the tube wall to become thinner and ultimately leading to tube bursting.

关 键 词：水冷壁管 相变组织 异物堵塞 短期过热 

分 类 号：TM621.2[电气工程—电力系统及自动化]