油缸用碟簧断裂分析

摘要

50CrVA钢制油缸用碟形弹簧在服役的早期发生断裂。采用直读光谱仪、洛氏硬度计、金相显微镜、扫描电镜等对该碟形弹簧的化学成分、硬度、非金属夹杂物、表面脱碳层、显微组织和断口形貌进行了分析。结果表明，50CrVA钢碟簧断裂是疲劳断裂，裂纹源由支撑面的加工硬化表层与次表层中的夹杂物共同作用所形成。提高碟簧使用寿命的措施是改善原材料的纯净度和提高表面加工质量。%Premature fracture of 50CrVA steel dished spring used in a oil vat occurred in service.The chemical composition,hardness,non-metallic inclusions,decarburized case,microstructure and fracture morphology of the dished spring were checked by direct-reading spectrometer,Rockwell hardness tester,OM and SEM.The results show that the rupture of the 50CrVA dished spring is a fatigue fracture,and the crack initiation arises from the action of work-hardened case of the support surface in combination with inclusions in the sublayer.Service life of the dished spring may be increased by an improvement on the raw material purity and increase in working quality of the surface.