某输电线路悬式绝缘子用锁紧销失效原因分析  

Analysis of the failure causes of the locking pin in suspension insulators of a transmission line

作　　者：童元浩 马平 包艳蓉 杨伟东 李亮 TONG Yuanhao;MA Ping;BAO Yanrong;YANG Weidong;LI Liang(Ningxia Electric Power Energy and Technology Co.,Ltd.,Yinchuan Ningxia 750011,China)

机构地区：[1]宁夏电力能源科技有限公司,宁夏银川750011

出　　处：《宁夏电力》2023年第4期64-69,共6页Ningxia Electric Power

摘　　要：针对宁夏某输电线路上悬式绝缘子用锁紧销断裂失效的问题,采用宏观检查、化学成分材质分析、金相检测、扫描电镜(scanning electron microscope,SEM)以及能谱仪(energy dispersive spectrometer,EDS)分析等方法进行了分析。研究发现材质为H62黄铜的锁紧销外表面覆盖一层纯铜,纯铜薄厚不均,与黄铜的界面分明,锁紧销裂纹起源于纯铜较厚位置,沿晶扩展,断口内有S元素存在。综合分析认为:锁紧销由表面溶解-再沉积机制主导发生脱锌腐蚀,脱锌后锁紧销表面力学性能下降,受力后服役过程中锁紧销脱锌表面萌生微裂纹,微裂纹以应力腐蚀机制扩展,锁紧销开裂失效。Addressing the fracture failure of locking pins used in suspension insulators on a transmission line in Ningxia,this study employs macroscopic examination,chemical composition analysis,metallographic testing,scanning electron microscope(SEM),and energy dispersive spectrometer(EDS)for investigation.It was observed that the locking pin,made of H62 brass,was enveloped with an uneven layer of pure copper,which had a clear interface with the brass.The cracking initiated at thicker areas of the copper coating and expanded along the grain boundaries,with sulfur elements present in the fracture.Through a comprehensive analysis,it is concluded that the locking pin experienced dezincification corrosion,primarily driven by the surface dissolution-reprecipitation mechanism,which consequently weakened its mechanical properties.Under stress during operation,micro-cracks formed on the dezincified surface and expanded through stress corrosion,resulting in the locking pin’s fracture failure.

关 键 词：黄铜 S元素 溶解-再沉积机制 脱锌 应力腐蚀 

分 类 号：TM755[电气工程—电力系统及自动化]