220kV变电站气体绝缘金属封闭开关设备操作机构碟形弹簧断裂分析

Analysis on Belleville Spring Fracture of Controlling Gear of Gas Insulated Switchgear in 220 kV Substation

通过宏观检查、金相试验、光谱分析、洛氏硬度试验、扫描电镜观察和能谱分析等试验,对一起220 k V变电站气体绝缘金属封闭开关设备(gas insulated switchgear,GIS)操作机构碟形弹簧断裂的原因进行分析。结果表明,碟形弹簧断裂的原因可以推断是弹簧下表面外径边缘至U形凹槽的区域在制造过程中形成原始缺陷,此处存在应力集中现象,在使用过程中,裂纹扩展并最终导致弹簧断裂。此外,碟形弹簧的显微组织保留了明显的马氏体针状形态,还出现了少量的羽毛状回火贝氏体,这些特征表明弹簧在使用过程中较易发生脆性断裂。

This paper analyzes reasons for Belleville spring fracture of controlling gear of gas insulated switchgear in 220 kV substation by experiments of microscopic test,metallographic test,spectral analysis,Rockwell hardness test,scanning electron microscope observation,energy spectrum analysis,and so on.Results indicate that reasons for Belleville spring fracture may be deduced for original defect of the area along the edge of external diameter of the lower surface of the spring to the U-shaped groove in manufacturing process where exists stress concentration,and in use procedure,cracks extend and finally cause spring fracture.In addition,microscopic structure of the Belleville spring keeps obvious martensitic acicular form and there is a little featheriness tempered bainite,which indicates that brittle fracture is easy to occur on the spring in use procedure.