风扇在做裸机测试时其轴芯发生了断裂。采用化学成分分析、金相检验、硬度测试、断口宏观和微观观察等方法对断裂原因进行了分析。结果表明: 由于风扇轴芯材料的过热加工, 导致材料晶界上碳化物的析出, 降低了晶界结合力, 再加上材料硬度偏高, 使脆性增加, 最终导致了成品的脆性断裂。

A fan shaft core was fractured during the model test. The fracture reasons were analyzed by means of chemical composition analysis, metallographic examination, hardness testing, macroscopic and microscopic observation of fracture. The results showed that the overheating treatment to material of shaft core led to carbide precipitate out at grain boundaries, which resulted in reduction of binding force of grain boundaries. In addition, the high hardness made the brittleness of material raise, then led to brittle fracture.