激光淬火对回转轴残余应力影响的研究

Influence of Laser Quenching on Residual Stress of Rotary Shaft

通过激光淬火对35CrMo合金结构钢回转轴截面突变处进行局部强化,利用金相显微镜观察激光强化后表面的显微组织,采用X射线衍射法测量激光淬火后表面的残余应力及其分布状态。研究结果表明:经激光表面淬火处理后,回转轴表面组织由索氏体变为细小的马氏体,晶粒更加细化,组织分布较均匀。平行于激光扫描方向的表面残余压应力是未处理试样的2倍,垂直于激光扫描方向的表面残余压应力是原来的1.8倍,激光淬火后表面残余压应力是未处理前的1.9倍。由此可见,激光淬火能明显增大回转轴表面的残余压应力,有利于提高轴的疲劳性能,提高硬度。

By laser quenching,the abrupt change of rotary shaft of 35CrMo alloy structural steel was locally strengthened.The microstructure of the surface after laser hardening was observed by electron microscope.The residual stress and its distribution on the surface after laser quenching were measured by X ray diffraction.The results show that the surface structure of the rotary shaft changes from sorbit to fine martensite after laser surface quenching,and the grain is more fine.The surface residual compressive stress parallel to the laser scanning direction is twice as much as that of the untreated sample,and the surface residual compressive stress perpendicular to the laser scanning direction is 1.8 times of that of the original one.The surface residual compressive stress after laser quenching is 1.9 time of the untreated sample.Laser quenching can obviously increase the compressive stress on the surface of the rotary shaft and improve the fatigue performance and hardness of the shaft.