气闸门顶轴断裂原因

Fracture reason of gas apical axis

某核电厂气闸门顶轴发生断裂,采用宏观观察、化学成分分析、硬度测试、金相检验和断口分析等方法分析其断裂原因,结果表明:材料中存在缺陷和网状铁素体,先共析铁素体使材料的强度与冲击韧性降低,在受到切向应力的工况下,材料发生脆性断裂。

The gas apical axis of a nuclear power plant fractured.The fracture reasons were analyzed by means of macroscopic observation,chemical composition analysis,hardness test,metallographic examination and fracture surface analysis.The results show that there were defects and reticular ferrite in the material.The strength and impact toughness of the material were reduced by the proeutectoid ferrite,and the brittle fracture of the material occurred under the condition of tangential stress.