超超临界机组水冷壁管弯曲面失效分析  

Failure Reasons Analysis on Bend Surface of Water Wall Tube for Ultra Supercritical Unit

作　　者：吴优福 侯召堂[2] 

机构地区：[1]神华(福建)能源有限公司,福建福州350004 [2]西安热工研究院有限公司,陕西西安710054

出　　处：《东北电力技术》2017年第3期45-49,55,共6页Northeast Electric Power Technology

摘　　要：采用化学成分分析、硬度检测、金相观察、扫描电镜断口分析、断口表面腐蚀产物的能谱分析以及有限元数值模拟等手段,对某发电公司的水冷壁管失效泄漏原因进行分析。结果表明:钢的化学成分符合GB5310标准的要求,失效管的硬度仍在DL/T 438—2009标准的控制范围,珠光体仅发生了轻微球化,断口属于典型热疲劳开裂。分析认为:水冷壁制作过程中弯曲工艺不合理所致的内裂纹或残余应力过大,可能是导致管子弯曲处过早失效开裂的主要原因;腐蚀烟气对热疲劳开裂起到加速作用。The causes of the cracks of water wall tubes are analyzed by means of chemical composition, hardness testing, metallo- graphic observation, fracture analysis, spectrum analysis of corrosion products and finite element numerical simulation. The results show that the chemical composition of the steel meets the requirements of the GB5310 standard, the hardness of water wall tubes still meets DL/T 438-2009 standard. Spheroidization of pearlite in water wall steel is slight. The tracture belongs to a typical thermal fa- tigue crack. The internal crack or the residual stress caused by the bending process is too large which may be the main reason for the premature failure. Corrosion of flue gas plays a role in the promotion of thermal fatigue cracking.

关 键 词：水冷壁管 热疲劳 弯曲工艺 腐蚀烟气 

分 类 号：TM621[电气工程—电力系统及自动化]