The fracture of stuffing box was caused by fatigue, which resulted from the maximum stress concentration on the centripetal border of the oil hole.

• 结果表明：材料成分和显微组织均符合要求；裂纹起源于输油孔的侧壁；填料盘的失效模式为疲劳失效，内压在填料盘内部输油孔上产生的应力集中导致了填料盘的疲劳失效。