通过宏观检查、化学成分分析、硬度测试以及金相检验等结果分析, 确定了重型卡车用钢板弹簧的断裂原因。结果表明: 因超载使钢板弹簧出现过度反弓, 造成板簧卡中的螺栓杆与钢板弹簧动态接触, 发生磨损腐蚀, 形成凹坑, 成为应力集中点;在过大的交变应力作用下, 应力集中点萌生裂纹并不断扩展, 最终造成钢板弹簧疲劳断裂。最后提出了防止其发生断裂失效的预防措施。

The fracture cause of heavy truck leaf spring was researched by macro examination, chemical compositions analysis, hardness test and metallographic examination. The results show that leaf spring excessive inverse arch-shaped for overload caused frictional contact between the plate spring bolt and the leaf spring and formation of erosion corrosion pits. Under the action of large alternating stress, the erosion corrosion pits became stress concentration positions and produced cracks. The cracks propagated gradually and finally resulted in fatigue fracture of the leaf spring. At last, measures of preventing leaf spring fracture accident were put forward.