超超临界火电机组给水泵汽轮机20Cr13钢动叶片断裂原因  

Cause of 20Cr13 steel moving blade fracture in the feed pump turbine of ultra supercritical thermal power units

作　　者：臧利永 张涛[2] ZANG Liyong;ZHANG Tao(Inner Mongolia Jingning Thermal Power Co.,Ltd.,Ulanqabt 012000,China;Inner Mongolia Electric Power Research Institute,Hohhot 010020,China)

机构地区：[1]内蒙古京宁热电有限责任公司,乌兰察布012000 [2]内蒙古电力科学研究院,呼和浩特010020

出　　处：《理化检验（物理分册）》2024年第5期74-78,共5页Physical Testing and Chemical Analysis(Part A:Physical Testing)

摘　　要：某超超临界机组在运行过程中,其给水泵汽轮机第4级20Cr13钢动叶片发生断裂事故。采用宏观观察、化学成分分析、金相检验、力学性能测试、扫描电镜及能谱分析等方法分析了叶片断裂的原因。结果表明:给水泵汽轮机部分动叶片装配不当,叶根与叶根槽装配间隙偏大,叶片明显松动;在转子长期高速转动过程中,叶片承受了较高水平的交变循环载荷,部分装配间隙大的动叶片叶根与叶根槽接触部位发生微动疲劳损伤,叶根周向边缘发生双向多源性疲劳开裂,裂纹逐步扩展,最终导致叶片断裂。During the operation of a certain ultra supercritical unit,a fracture accident occurred on the fourth stage 20Cr13 steel moving blade of the feedwater pump turbine.The causes of blade fracture were analyzed using methods such as macroscopic observation,chemical composition analysis,metallographic examination,mechanical property testing,scanning electron microscopy and energy spectrum analysis.The results show that some moving blades of the feed pump turbine were improperly assembled,and the gap between the blade root and the blade root groove was too large,resulting in obvious loosening of the blades.During the long term high speed rotation of the rotor,the blades bore a high level of alternating cyclic load.Some moving blade roots with large assembly gaps and the contact area of the blade root groove experienced micro fatigue damage.The circumferential edge of the blade root underwent bi-directional multi-source fatigue cracking,and the cracks gradually expanded,ultimately led to blade fracture.

关 键 词：给水泵汽轮机 动叶片 断裂 微动疲劳 装配间隙 交变循环载荷 

分 类 号：TB31[一般工业技术—材料科学与工程] TG115.2[金属学及工艺—物理冶金]