平面涡卷弹簧T9A应力腐蚀断裂分析

Analysis on Stress Corrosion of Plane Scroll Spring T9A

某飞机电机在外场工作一定时间后,定点检查发现电机的平面涡卷弹簧断裂。通过宏观观察、电镜能谱检查、化学成分分析、金相组织检查和硬度检测等方法对弹簧断裂的原因进行分析。结果表明:该弹簧断裂属于应力腐蚀断裂,断裂原因为弹簧表面受拉应力作用,同时环境介质Cl-、S-在T9A钢表面的化学镀镍层与基体结合处产生腐蚀微裂纹,并向基体内部扩展,最终导致弹簧断裂。

An electric plane scroll spring of a generator fractures after service for several hours. By macroscopic,observation, EDS analysis, chemical composition analysis, micro-structure and hardness testing, the cause of the plane scroll spring was comprehensively analyzed. The results show that：the type of spring fracture is stress corrosion fractre. The reasons for the fracture is due to the tensile stress on spring surface, and at the same time, Cl-, S-in environmental medium can lead to the corrosion micro-crack at the junction of platting material of surface of T9 A steel and matrix, and then the crack extends to internal matrix, finally resulting in the fracture.