柴油机轴承盖螺栓断裂分析

Fracture Analysis on Bearing-cap Bolt of the Diesel Engine

柴油机发生多起轴承盖螺栓六角头与杆部过渡处断裂的故障,行驶里程为30000～70000km。对故障件进行了断口分析、化学成分分析、力学性能检测、金相组织及硬度检验。结果表明,轴承盖螺栓属氢脆断裂。对库存件进行了氢含量检测,发现氢含量过高。提出了改进建议,取得了良好的效果。

Some bearing-cap bolts of the diesel engine were found fractured on the intersection between the hexagon head and the pole,after the diesel engines ran 30000～70000km.The fractured bearing-cap bolt was analyzed by fractography,chemical composition analysis,mechanical properties testing,metallographic examinations and hardness testing.The results show that the bearing-cap bolt is hydrogen embrittlement.Hydrogen-content inspection on the bolts shows hydrogen-content is excessive.Some improvements are proposed and good effects are obtained.