35钢延长拉杆过热断裂原因分析

延长拉杆是输电线路重要的承载连接金具.结合一起500 kV输电线路延长拉杆断裂实例,通过对延长拉杆进行宏观检测、材料成分检测、室温和高温力学性能检测、不同热处理条件下的金相组织观察、断口形貌观察、通流试验等进行分析,研究引起延长拉杆过热断裂的原因.结果表明,当引流线夹接触不良或断开时,会导致延长拉杆通过大电流后长时间严...

Analysis on reasons of overheating fracture for 35 steel extension rod

Extension rod is an important load-bearing connection fitting for transmission lines. Therefore, for an example of an extension rod fracture for 500 kV transmission line, the reasons causing the overheating fracture of extension rod were investigated by macroscopic observation, material composition detection, mechanical performance detection at room temperature and high temperature, metallographic structure observation under different heat treatment conditions, fracture morphology observation and current test of extension rod. The results show that the poor contact or disconnection of jumper conductor clamper causes the extension rod to generate serious heat for a long time owing to passing through large current, the pearlite structure of the extension rod changes from lamellar structure to spherical structure, and creep occurs under the action of wire tension, then the bearing area decreases and the tensile strength has a significant drop, finally fracture occurs on the extension rod under the action of wire tension. Thus, the research provides guide for the line patrolling, installation and repair work of jumper conductor clamper.