ZL102铝合金均压环夹板的断裂原因

Fracture Causes of ZL102 Aluminium Alloy Equalizing Ring Splint

某交流输电线路的ZL102铝合金均压环夹板发生断裂失效。对现场失效构件进行了理化检验,在模拟现场腐蚀环境中对ZL102铝合金进行电化学测试和腐蚀形貌观察,从而分析了材料的失效过程。结果表明:铸造缺陷是导致铝合金夹板失效的关键原因,在交流电作用下,铸造缺陷成为失效位点;铝合金失效过程主要分为腐蚀产物层的防护阶段、点蚀萌生和发育阶段和蚀坑纵向发展阶段;随着腐蚀时间的延长,开路电位表现为基本不变→正向偏移→基本不变的变化规律,腐蚀电流密度表现为缓慢增大→迅速增大→缓慢增大的变化规律,电荷转移电阻持续减小,但减小速率逐渐变缓。

Fracture failure happened in a ZL102aluminum alloy equalizing ring splint of an alternating current(AC)transmission line.Physical and chemical tests were carried out to the on-site failure component,and electrochemical tests and corrosion morphology observation of ZL102aluminum alloy were carried out in the simulated on-site corrosion environment,so as to analyze the failure process of the material.The results show that casting defects were the key cause of the failure of the aluminum splint.Under the action of alternating current,casting defects were worked as the failure site.The failure process of the ZL102aluminum alloy was mainly divided into the protection stage of corrosion product layer,the initiation and development stage of pitting corrosion and the longitudinal development stage of pitting pit.With the increase of corrosion time,the open-circuit potential showed a change rule of basically constant→forward migration→basically constant,the corrosion current density showed a change rule of slowly increasing→rapidly increasing→slowly increasing,and the charge transfer resistance continued to decrease,but the decreasing speed gradually slowed down.