大功率发动机曲轴疲劳断裂失效分析

High Power Engine Crankshaft Fatigue Fracture Failure Analysis

通过对发动机曲轴的化学成分、显微组织及裂纹宏微观形貌进行分析,同时结合硬度测量和力学性能测试等手段,全面梳理了曲轴裂纹的失效原因。结果表明,曲轴断裂疲劳源位于连杆颈油孔内壁,距离连杆颈表面大约7mm处。在此处,由于连杆颈油孔内壁的局部区域加工质量较差,导致了疲劳源的萌生,加剧了轴颈内部裂缝的形成,最终在持续的疲劳扩展过程中诱发了裂纹失效。

By analyzing the chemical composition,microstructure,and macro-and micro-morphology of the engine crankshaft cracks,combined with hardness measurement and mechanical property testing,the failure cause of the crankshaft cracks was comprehensively analyzed.The results showed that the fatigue source of the crankshaft fracture was located in the inner wall of the connecting rod journal oil hole,approximately 7mm from the surface of the connecting rod journal.At this location,due to poor processing quality in some ar-eas of the inner wall of the connecting rod journal oil hole,the fatigue source was initiated,which exacerbated the formation of cracks inside the journal,eventually inducing crack failure during continuous fatigue propagation.