白莹，宋建锋，周廷矗，张光林，张红艳

（中国石油集团济柴动力总厂，山东 济南 250306）

    摘要：某柴油机曲轴采用谐振疲劳试验系统进行静态与动态疲劳试验，3根试验曲轴均在连杆轴颈与曲柄的过渡处，与轴颈呈45度角处出现断裂，通过曲轴的材料化学成分、断口形貌、金相组织检验、氮化层、力学性能等方面的分析，确认导致曲轴疲劳断裂的主要原因是曲轴高应力集中和高应力区存在非金属夹杂物。

    关键词：曲轴；疲劳试验；断裂

    Abstract: Static and dynamic fatigue test is performed on resonance oscillation fatigue test system for engine crankshaft.3 crankshafts are cracked at transition area between connecting rod journal and crank web where 45°angle is formed with connecting rod journal.After analysis of chemical component of the material,fracture apearance,metallographic structure inspection,natrided layer,mechanical property etc,it is confirmed that main reason to cause fatigue crack is due to high stress concentration and non-metallic inclusion at this high stress concentration area.

    Keywords: Crankshaft;Fatigue Test;Crack