给水泵汽轮机动叶片微动磨损疲劳断裂的失效特征分析  

Failure characteristics analysis for fretting wear fatigue fracture of feed pump turbine blades

作　　者：肖中图 史志刚[2] 李春光 李梁[2] 李长旭 谷伟伟[2] 张宝柱[2] XIAO Zhongtu;SHI Zhigang;LI Chunguang;LI Liang;LI Changxu;GU Weiwei;ZHANG Baozhu(Shenhua Guohua Ningdong Power Generation Co.,Ltd.,Lingwu 750408,China;Xi’an Thermal Power Research Institute Co.,Ltd.,Xi’an 710054,China)

机构地区：[1]神华国华宁东发电有限责任公司,宁夏灵武750408 [2]西安热工研究院有限公司,陕西西安710054

出　　处：《热力发电》2021年第6期157-162,共6页Thermal Power Generation

摘　　要：某超超临界600 MW机组给水泵汽轮机第2级动叶片在投产初期就发生微动磨损疲劳断裂失效,对此通过故障现场检查,分析断裂叶片的材质和断口形貌,采用有限元计算分析叶片离心应力,以及综合分析叶轮叶片系统振动特性,得到微动磨损疲劳断裂失效的特征及原因。分析认为:动叶片的微动磨损疲劳断裂均起源于叶根第1齿工作面,第1齿工作面和叶顶一侧表面存在轮胎印型擦痕、磨损斑点、表面发亮及小裂纹等磨损痕迹,第1齿工作面截面存在多条呈分层的裂纹,源区的微观组织和硬度与基体相比明显异常,齿面和断口一般无腐蚀性元素;引起第2级动叶片微动磨损疲劳断裂失效的原因为装配质量不良。Fretting wear fatigue fracture failure occurred at the beginning of service of the second stage moving blade of feedwater pump turbine in an ultra supercritical 600 MW unit.Field investigation was performed to analyze the material and fracture morphology of the fractured blade.Moreover,finite element calculation was carried out to study the centrifugal stress of the blade.Through comprehensive analysis on vibration characteristics of the impeller blade system,the failure characteristics and causes of fretting wear were obtained.The results show that,the fretting wear fatigue fracture originated from the first working face of blade root.There existed wear marks such as tire mark,wear spot,surface brightness and small crack on the surface of the first tooth working face and blade top side.There were many cracks with mechanical fatigue which were delamination cracking in the section of the first tooth working face.The microstructure and hardness of the source area were obviously abnormal compared with the matrix.The reason of fretting wear fatigue fracture of the second stage moving blade was poor assembly quality.

关 键 词：给水泵汽轮机 动叶片 微动磨损 疲劳断裂 装配质量 

分 类 号：TG142.24[一般工业技术—材料科学与工程] TG115.21[金属学及工艺—金属材料]