卡车柴油机高压油管开裂分析

Failure Analysis on High Pressure Fuel Pipes Used in Truck Diesel Engine

多批次卡车柴油机高压油管在服役中过早发生开裂,利用体视显微镜、扫描电子显微镜对开裂高压油管的裂纹形态及断口表面进行观察。结果表明:高压油管的失效模式均属于疲劳开裂;裂纹起源于内孔清理喷丸过程中形成的纵向微切削损伤,在内孔油压导致的环向拉应力作用下,疲劳裂纹从油管内表面向外表面扩展,最终导致油管开裂漏油。

The high pressure fuel pipes used in truck diesel engine cracked in service.The crack morphology and fracture surfaces of cracked fuel-pipes were observed by stereomicroscope and scanning electron microscope.The results indicate that the failure mode of all the fuel-pipe was fatigue fracture.The crack origin was originated from the m icro-cutting marks on the internal surface due to grit-blasting for cleaning internal hole.The crack propagated from the internal surface toward the external surface under the circum ferential tensile stress due to the operating oil-pressure in the internal hole to lead to fatigue.