铁路用的一种ω形弹条在疲劳试验过程中当载荷循环约300万次时发生断裂, 通过化学成分分析、硬度测试、显微组织和断口形貌观察等方法, 分析了弹条的断裂原因。结果表明: ω形弹条在疲劳试验过程中因弹条尾部跟端支点处承受的交变载荷相对较大, 容易产生较大的应力集中, 且该处存在腐蚀坑缺陷, 从而促进了疲劳裂纹的萌生和发展, 最终导致弹条疲劳断裂失效。

The ω-shaped spring rod for a railway fractured when the load cycle was about 3×106 times in a fatigue test. The reasons for spring rod fracture were analyzed by chemical composition analysis, hardness testing, microstructure observation, and fracture morpholohy examination. The results show that a large stress concentration happened on the fulcrum at the end of tail of the ω-shaped spring rod because the alternating load in this location was larger than in other areas during the fatigue test. Moreover, there were corrosion pits on the fulcrum. These two reasons promoted the initiation and development of the fatigue cracks, which eventually led to fatigue fracture failure of the ω-shaped spring rod.