某电厂高中压缸高温螺栓断裂的原因

Causes of Fracture of High Temperature Bolt of High-Medium Pressure Cylinder in a Power Plant

某电厂在运行1.5×10^(5)h后,高中压缸高温螺栓发生断裂。通过化学成分分析、力学性能试验、断口分析、显微组织观察和能谱分析等方法,分析了螺栓断裂的原因。结果表明:螺栓在长期高温和复杂应力作用下,局部晶界处发生蠕变,材料性能衰退,在机组运行过程中裂纹在蠕变处萌生,并沿晶界扩展,最终导致螺栓断裂。

After a power plant operated for 1.5×10^(5)hours,high temperature bolt of high-medium pressure cylinder was fractured.Through chemical composition analysis,mechanical performance test,fracture analysis,microstructure observation and energy spectrum analysis,the reasons for bolt fracture were analyzed.The results showed that under the action of long-term high temperature and complex stress,creep occurred at local grain boundaries and the material properties declined.During the operation of the unit,cracks initiated at creep location and propagated along grain boundaries,eventually leading to bolt fracture.