摘要
超高压开关断路器的三工位机构是电力系统中一种重要的机械装置。铜螺母是三工位机构中不可或缺的关键部件,其过早失效严重影响断路器的稳定运行及使用寿命。为探求三工位机构铜螺母发生断裂的原因,通过不同的分析方法对断裂铜螺母进行了失效分析。采用光学显微镜、扫描电子显微镜和金相显微镜观察断口的宏观形态、微观形貌以及显微组织结构,使用X射线荧光光谱仪及电子万能试验机确定了铜螺母母材的成分和力学性能。结果表明:铜螺母断口起裂区存在多处裂纹源且晶粒粗大,大量析出颗粒存在于晶界处形成网状分布。铜螺母的断裂失效是由疲劳破坏引起的,属于累积损伤破坏。铜螺母裂纹源产生于铜螺母轴销根部的变径位置,该位置在结构上为应力集中区,是铜螺母结构的薄弱位置,在长期交变应力作用下,极易萌生裂纹并逐步扩展,最终导致铜螺母断裂失效。
The three-position mechanism represents a critical mechanical component in ultra-high voltage switch circuit breakers,with the copper nut serving as a pivotal element.Premature failure of this component can significantly compromise the operational stability and longevity of the circuit breaker.This comprehensive investigation employs advanced analytical techniques to elucidate the underlying fracture mechanisms of the copper nut.Utilizing a multifaceted analytical approach,the study systematically examined the fracture morphology and material characteristics.Optical microscopy,scanning electron microscopy,and metallographic microscopy were employed to scrutinize the fracture surface and microstructural features.Complementary analyses using X-ray fluorescence spectrometry and electronic universal testing machine characterized the material’s compositional and mechanical properties.The investigation revealed critical insights into the failure mechanism.Multiple crack initiation sites were identified within the fracture zone,characterized by coarse grain structures and an extensive network of precipitate particles localized at grain boundaries.The failure mode was definitively classified as cumulative fatigue damage.The primary crack source originated at the diameter transition of the shaft pin root’a structural stress concentration zone that represents the most vulnerable point in the copper nut’[KG-4]s mechanical design.The findings underscore the importance of structural geometry and material microstructure in predicting and mitigating mechanical failure in critical electromechanical components.
作者
张树民
王小平
田静
许慧霞
刘珑
丁宁
ZHANG Shumin;WANG Xiaoping;TIAN Jing;XU Huixia;LIU Long;DING Ning(Tai’an Taihe Power Equipment Co.,Ltd.,Tai’an 271000,China;Research Center of Failure Analysis and Engineering Safety Assessment,Shandong Analysis and Test Center,Qilu University of Technology(Shandong Academy of Sciences),Jinan 250014,China)
出处
《山东科学》
2025年第5期56-63,共8页
Shandong Science
基金
山东省科技型中小企业创新能力提升工程项目(2023TSGC0618)。
关键词
超高压开关
三工位机构
铜螺母
疲劳
断裂
应力集中
ultra-high voltage circuit breaker
three-position mechanism
copper nut
fatigue
fracture
stress concentration
