摘要
6106型柴油机在载重车上运行4万公里和8万公里后发生排气阀"掉头"和"掉块"事故,本文对失效排气阀的金相组织和断口进行了观察分析,分析结果表明,金相组织正常,可以排除冶金质量和热处理的问题,发生在颈部的"掉头"事故,是由于机加工精度不高,表面存在"沟槽"引起。发生在盘部的"掉块"事故,是由于21-4N钢高温强度不足引起的。
＂ Head-off＂ and ＂piece-off＂ accidents occurred when 6106-type diesels of trucks served at 40000km and 80000km respectively. The microstructure and morphology of fracture surface of failed exhausted valves were investigated. It was found that the microstructure is normal, implying that metallurgical processes and heat treatment may not contribute to the failure of the valves. Meanwhile, ＂ head-off＂ of the valves is basically resulting from the fact that non-enough machining accuracy, as some grooves existed in the surface of the valves. ＂Piece-off＂ failure is due to the non-enough elevated temperature strength of 21-4N steel.
出处
《失效分析与预防》
2006年第3期33-37,共5页
Failure Analysis and Prevention
关键词
柴油机
排气阀
沟槽
裂纹
diesel
exhausted valves
groove
fracture
