火力发电厂末级过热器短期超温失效分析及预防措施Failure Analysis and Prevention of Short-time Overheat of Last Stage Superheater in Thermal Power Plant
张海军,田永财
ZHANG Haijun,TIAN Yongcai
摘要(Abstract)：
针对某发电厂锅炉末级过热器发生爆管的事故,采取宏观检查、管子几何尺寸测量、金相分析、硬度测试、力学性能试验、化学元素分析、扫描电子显微镜观察等分析手段,查明了该末级过热器爆管的原因并提出针对性预防措施。分析结果表明,该管失效是因为末级过热器管在运行过程中,冷却条件恶化,导致管子处于干烧状态,使管壁温度短期内突然升高,致使管子的抗拉强度急剧下降,管子应力超过屈服极限,产生剪切断裂而爆管。针对此次事故,发电厂应加强技术监督、可靠性管理和采取针对性措施,从而最大程度地避免爆管事故的发生。
Aiming at the last stage superheater tube burst in a power plan, macroscopic detection, tube dimension measurement, metallurgical analysis, hardness test, mechanical performance test, chemical element analysis and scanning electron microscope are employed to find out the tube burst causes and put forward precautions. The analysis result shows that the tube failure results from cooling condition deterioration, which leads to dry heating of tube and sharp increase of tube wall temperature; the tube stress exceeds yield limit and shear fracture occurs consequently. The power plant must strengthen technical supervision, reliability management and take corresponding measures to minimize tube burst in the future.
关键词(KeyWords)：
锅炉;末级过热器;氧化皮;短期超温;爆管
boiler;last stage superheater;oxide skin;short-time overheat;tube burst
基金项目(Foundation):
作者(Author):
张海军,田永财
ZHANG Haijun,TIAN Yongcai
DOI: 10.19585/j.zjdl.201806015
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