200MW汽轮机末级叶片断裂原因分析  

Fracture Reason Analysis of Last Stage Blade of 200MW Steam Turbine

作　　者：刘爽[1] 赵永宁[1] 刘玉智[1] 

机构地区：[1]山东电力研究院,济南250002

出　　处：《汽轮机技术》2011年第4期311-314,共4页Turbine Technology

摘　　要：对某火力发电厂200MW汽轮机末级叶片断裂原因进行分析。通过金相检测、力学性能检测、化学元素成分分析及对断口的宏观检查、扫描电镜和能谱分析,认为断口为典型的疲劳断口,裂纹源位于叶片出汽侧某一点状蚀坑处,由于水蚀区域造成应力集中,并且叶片材料韧性偏低,存在S元素成分偏析,所以机组运行过程中,在交变应力和残余应力的共同作用下导致疲劳裂纹的产生和扩展,使叶片最终断裂。Fracture reason of last stage blade of power plant 200MW steam turbine was analyzed. The fracture surface of blade was analyzed and observed by means of metallurgical microscope test, mechanical properties test, elemental composition analysis and macro test, scanning electron microscopy together with energy dispersive spectrometry. Analysts believed that the fracture surface was typical fatigue-fracture; crack source was located in the steam side of the blade at some corrosion pits. Because the water-corrosion zone leaded to stress concentration, the blade was low toughness and Sulfur elements composition segregation. Alternating stress and residual stress together leaded to the produce and expands of fatigue crack in operation of steam turbine.

关 键 词：叶片 疲劳 断裂 

分 类 号：TK267[动力工程及工程热物理—动力机械及工程]