Fatigue Cracks Analysis of Automotive Wheel Hubs

针对汽车轮毂在台架试验后产生疲劳裂纹的问题，采用体视显微镜、金相显微镜、扫描电镜和硬度测试设备等，对失效的汽车轮毂的成分、组织和性能进行分析。结果表明：失效的主要原因是热影响区与焊接区附近有脆性氧化夹杂物形成裂纹源；焊接热影响区的马氏体板条粗化，承受疲劳载荷的能力弱导致疲劳开裂。In view of fatigue cracks in automotive wheel hubs after bench testing, the composition, microstructure, and mechanical properties of the failed automotive wheel hubs are analyzed by using stereomicroscopes, optical microscopes, scanning electron microscopes, and hardness testing equipment. The results show that the main causes of the failure are the formation of brittle oxide inclusions near the heat affected zone and welding zone, which form crack sources. The martensite Flat noodles in the welding heat affected zone are coarsened, and the ability to bear fatigue load is weak, leading to fatigue cracking.