挖掘机销轴的断裂失效分析

Analysis of A Pin of Excavator Failure

挖掘机的销轴在工作过程中发生断裂。本文通过对断裂销轴的宏观断口、微观形貌、显微组织、化学成分、材料硬度及销轴的受力等分析,结果表明,销轴断裂为典型的疲劳断裂。疲劳源位于油孔处,属油孔部位应力集中造成的。因此,油孔位置设计不合理是销轴断裂的主要原因。另外,疲劳源始于油孔内的切削刀痕,切削刀痕也是销轴断裂的原因之一。结合以上分析,本文提出了解决问题的方法,优化了工艺路线方案,为提高销轴的使用寿命指明了方向。

Pin of excavator breakage occurs during operation, through the macroscopic observation and analysis to the fracture, metallurgical structure analysis under microscope, Microscopic analysis of the electron microscope, chemical composition analysis, hardness testing analysis. Mechanical Performance Analysis and so on .The results show that the fracture of the pin is typical brittle Fatigue fracture and belongs to early failure.pin caused stress concentration at the hole and ,fatigue crack initiation a and propagation at the hole located.The position of the hole design unsuitable is one of the reasons pin breakages. leaving traces of the existence of lane geometry gap after turning when turning hole chamfering.Notched fatigue and the gap causing stress concentration is also one of the reasons that pin fractures.Finally, given above the problems identified find solutions to problems and further optimize the process route programs to improve the life of the pin.