某热电厂凝结水泵轴断裂原因分析

某热电厂功率为100 kW转速为1 400 r/min的凝结水泵使用6 a后,6台中的1台泵轴发生断裂,断裂时断口平整,垂直于轴向,断口正中心有一径向裂纹。通过轴体材料的化学分析、机械性能分析及相应的宏观和微观观察分析,发现凝结水泵轴材质为45号钢,但并没有经过正常的调质处理,强度偏低;该断轴起源于轴心的冶金缺陷,后以扭转疲劳方式扩展至最后断裂。根据以上分析结果,提出相应的热处理工艺,并建议对轴体作必要的无损检测。

Analysis of Cracking of Condensate Pump Shaft in a Thermal Power Plant

The shaft of one of 6 condensate water pumps with a power of 100 kW and speed of 1 400 r/min in a thermal power plant fractured after 6 years’ operation.The fracture was flat and perpendicular to axial,and there was a radial crack in the middle of fracture.The chemical analysis,mechanical analysis and corresponding macro and micro analysis found that the 45# steel material for condensate water pump had not been properly treated by quenching and tempering and the strength was low.The metallurgical defects from center of shaft developed,leading to final fracture.The corresponding heat treatment process is proposed and non-destruction examination is recommended for shaft.