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超临界机组低压转子叶片断裂原因分析
Analysis of Cause of Low Pressure Rotor Fracture in Supercritical Unit
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- DOI:
- 作者:
- 黄桥生 章亚林 牟申周 李秋白 刘玉海
HUANG Qiaosheng;ZHANG Yalin;MOU Shenzhou;LI Qiubai;LIU Yuhai
- 作者单位:
- 国电科学技术研究院有限公司 国电河南电力有限公司
Guodian Science and Technology Research Institute Co.,Ltd.,Wuhan 430066,China;Guodian Henan Electric Power Co.,Ltd.,Wuhan 450000,China
- 关键词:
- 喷丸检查 磁记忆 腐蚀介质 积盐分析
pill test magnetic memory corrosion medium salt accumulation analysis
- 摘要:
- 某超临界600 MW机组发生了叶片断裂事故,分别利用光学显微镜、扫描电镜和磁记忆检测仪对叶片的金相组织、叶片表面垢层(腐蚀产物)组成以及叶片应力分布进行分析。结果表明,叶片喷丸质量不佳,在腐蚀环境中产生点腐蚀坑,进汽侧边缘的点腐蚀坑形成微裂纹,在运行中受到离心力及交变汽流力等作用下,产生应力集中,裂纹扩展直至发生疲劳断裂。为了保障该汽轮机安全运行,提出加强汽水品质监督,在大修揭缸检查时,对点腐蚀等微缺陷进行检查以及采取喷涂技术对叶片进行表面防护等措施。A blade fracture accident occurred in a supercritical 600 MW unit.Optical microscopy,scanning electron microscopy and magnetic memory detector were used to analyze the metallographic structure of the blade,the composition of the scale layer(corrosion product)on the blade surface and the stress distribution of the blade.The results show that the quality of blade shot peening is poor,pitting corrosion pits are generated in the corrosive environment,and micro-cracks are formed in the pitting corrosion pits on the edge of steam inlet side.Under the action of centrifugal force and alternating steam flow force in operation,stress concentration is generated,and crack propagation occurs until fatigue fracture occurs.In order to ensure the safe operation of the steam turbine,it is proposed to strengthen the quality supervision of aerated water,inspect the micro-defects such as pitting corrosion during the inspection of the cylinder in overhaul,and adopt spraying technology to protect the blade surface.