某车型轮毂螺栓断裂的原因分析

Analysis on the Fracture of Wheel Hub Bolt on a Certain Car

某车型车轮毂螺栓在车辆行驶过程中发生断裂。为了研究断裂原因,应用扫描电子显微镜、直读光谱仪、光学显微镜及疲劳试验机对故障螺栓进行了化学成分、宏观、微观及模拟对比等分析。结果表明,其断裂形式为脆性断裂。脆性断裂的产生是由于热处理过程的增碳及滚丝收尾不合格,致使应力集中,加速了螺栓裂纹的产生、扩展,从而导致轮毂螺栓在装车使用后不久便发生了断裂失效。

An automobile wheel hub bolt crack occurred in the process of vehicle. In order to study the crack reason, scanning electron microscopy, direct reading spectrometer, optical microscope and fatigue testing machine were used to make chemical composition analysis, macro analysis, micro analysis and simulation comparison analysis. The results show that the crack mode is brittle crack. The brittle crack is due to carburizing in the heat treatment process and unqualified rolling finishing, which cause stress concentration, accelerating generation and expansion of the bolt crack. As a result, rupture failure is occurred on hub bolt shortly after use.