超高压开关断路器三工位机构铜螺母断裂失效原因分析

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中图分类号：TG115 文献标志码：A 文章编号：1002-4026（2025）05-0056-08

Abstract：The thre-position mechanism representsacrical mechanical component in ultra-high voltage switch circuit breakers，with the copper nut serving asapivotal element.Prematurefailure of thiscomponent can significantly compromise theoperational stabityand longevityofthecircuit breaker.Thiscomprehensive investigation employs advancedanalyticaltechniquestoelucidatetheunderlying fracture mechanismsofthecoppernut.Utizingamultfaceted analyticalapproach，thestudysystematicallyexaminedthefracturemorphologyandmaterialcharacteristics.Optical microscopy，scanning electron microscopy，and metalographic microscopy wereemployed to scrutinize the fracture surfaceand microstructural features.Complementaryanalysesusing X-ray fluorescence spectrometryand electronic universaltesting machinecharacterizedthematerial’scompostionalandmechanicalproperties.Theinvestigationrevealed critical insightsintothefailuremechanism.Multiplecrack initiation sites wereidenifiedwithinthefracture zone， characterized bycoarse grain structures andanextensive network of precipitateparticles locaizedat grainboundaries. Thefailure mode wasdefitivelyclassiedascumulative fatigue damage.The primarycrack source originatedat the diameter transitionof the shaftpinroot’astructuralstress concentration zone that represents themost vulnerablepoint in the coppernut’s mechanical design.The findingsunderscore theimportance of structural geometryandmaterial microstructure in predicting and mitigating mechanical failure in critical electromechanical components.

KeyWords：ultra-highvoltage circuit breaker；three-positionmechanism；copper nut；fatigue；fracture；stress concentration

超高压开关断路器在电力系统中承担着关合、开断、保护、控制等重要功能，具有广泛的应用前景和重要的战略意义[1-2]。（剩余7188字）