摘要
某构件进行疲劳性能试验时,连接螺栓发生断裂。通过断口宏微观观察、金相组织检查、硬度及化学成分检测,确定了连接螺栓的断裂性质和原因。结果表明:连接螺栓的断裂性质为微动疲劳;断裂原因是球轴承上由于某种偶然因素形成缺口,导致球轴承上裂纹的萌生和扩展,球轴承裂纹的产生使得连接螺栓与球轴承之间的预紧力减小,局部松动而产生不均匀接触,在径向有规律的往复载荷作用下,导致连接螺栓产生微动磨损,进而发生微动疲劳断裂。
A connecting bolt fractured during fatigue test of one structural unit. Fracture mode and failure cause of the connecting bolt were concluded according to the results of macro and micro observation of fracture surface, metallurgical structure examination, hardness testing and chemical composition analysis. The results showed that the failure mode of the connecting bolt was fretting fatigue. A gap formed on the ball bearing by accident firstly, then a crack initiated and propagated from the gap which decreased the pretightening force of the connecting bolt and caused asymmetrical contact between the connecting belt and the ball bearing because of local loosening. Then fretting wear and fretting fatigue fracture happened on the connecting bolt under the radial cyclic load.
出处
《失效分析与预防》
2009年第4期225-228,共4页
Failure Analysis and Prevention
关键词
连接螺栓
微动磨损
预紧力
微动疲劳
connecting bolt
fretting wea
pretightening force
fretting fatigue
