针对某型发动机高压油泵柱塞套开裂失效事故,运用扫描电子显微镜、能谱仪、硬度计和光学显微镜等对失效件进行了分析。结果表明:导致柱塞套开裂的根本原因是其内在质量不良,存在严重带状碳化物,并导致其疲劳断口裂纹源区局部沿晶带状分布。并通过对市场服役件的检验分析,进一步对事故的概率分布进行了判断,为准确处理该事故提供了可靠的技术依据。

A certain engine high pressure fuel pump barrels cracking accident happened in a period of time and it was analyzed by means of SEM, EDS, hardness tester and optical microscope. The results indicate that the main cause for the cracking was the poor inner quality of the barrel material. There was serious banded carbide which caused intergranular banding fracture at the fatigue cracking source area. Moreover, high pressure fuel pump barrels disassembled from the engine in use were tested to estimate the failure accident probability. The analysis results provided a reliable technical evidence to treat this quality accident.