水电厂阀杆断裂原因分析

Causal Analysis of Valve Shaft Fracture in Hydropower Plant

采用光学显微镜、扫描电子显微镜、化学成分分析和硬度测试等方法,对某水电厂尾水闸门充水阀杆的断裂原因进行分析。结果表明:阀杆断裂的内因是热处理回火不充分,使材料硬度偏高,脆性增加;其外因是运行过程中振动使得螺纹受到碰撞和损伤,在应力集中的齿根处开裂扩展;对此提出了改进措施并取得较好效果。

The causes for valve shaft fracture in hydropower plant were analyzed by using optical microscope（OM）,scanning electronic microscope（SEM）,chemical composition analysis and hardness testing,etc.As the results showed,internally,the heat treatment under-tempering led to the high hardness and brittleness of the materials;externally,the vibration in the operation resulted in the screw collision and damage.Consequently the valve shaft cracked from gear tooth with serious stress concentration.Improvement measures were proposed and remarkable effects were achieved.