数控机床45钢转轴断裂失效分析研究

Research on 45 Steel Shaft Failure of Numerical Control Machine Tool

采用化学成分、力学性能、宏观和微观形貌、低倍组织、金相组织和显微维氏硬度测试等手段,对数控机床45钢转轴进行了断裂原因分析。结果表明,从化学成分和常温拉伸力学性能上来看,转轴基材符合国标对45钢的要求;旋转弯曲疲劳断裂是数控机床转轴的断裂模式;疲劳裂纹起源于表面微裂纹缺陷处,焊接后转轴内部微裂纹的产生以及严重的组织缺陷和内应力的存在,是转轴发生疲劳断裂的重要原因。

The 45 steel fracture reason of numerical control （NC） machine tool were investigated by chemical composition, mechanical properties, macroscopic and microscopic morphology, macrostructure, microstructure and micro-vickers hardness testing. The results show that the chemical composition and tensile mechanical properties of 45 steel are meet the requirement of national standard. The model is the rotating bending fatigue fracture of NC machine tool axis. The fatigue crack originates from the surface micro cracks defect, internal micro cracks after welding, severe tissue defect and the existence of internal stress, these are the important reasons for the shaft fatigue fracture.