砂轮约束磨粒喷射加工表面残余应力及摩擦特性

针对磨削后工件表面出现缺陷问题,提出砂轮约束磨粒喷射光整加工方法(AJF).试验在M7120平面磨床上完成,加工试样为Sa=0.6μm左右的45钢.工件表面残余应力用TW3040-60 X射线衍射仪测量;利用MG-2000型销盘式摩擦磨损试验机研究表面形貌对摩擦系数和磨损性能的影响.试验结果表明:随着加工时间的增加,磨削表面的残余拉应力逐渐变成压应力,加工时间对残余应力有显著影响.Sa值由0.626μm下降到0.2μm左右.光整加工后表面摩擦系数和磨损量与磨削加工表面相比明显降低,表面硬度随加工时间的延长逐渐提高,这与工件表面残余应力的变化一致.

Residual Stress and Tribological Characteristics of Ground Surface After Abrasive Jet Restricted by Grinding Wheel

The residual stress and tribological characteristics of ground surface of a 45 steel workpiece as specimen after the AJF restricted by grinding wheel were investigated experimentally on M7120 surface grinder with the value of ground surface roughness Sa=0.6 μm. The residual stress of ground surface of specimen was measured with TW3040-60 X-ray diffractometer, and the effects of surface morphology on the friction coefficient and abrasiveness of the ground surface after AJF were investigated with the MG-2000 pin-on-disk wearing tester. The results showed that the tensile stress of ground surface changes into compressive stress gradually along with the increasing grinding time which affects greatly the residual stress, and the Sa value decreases from about 0.626 μm to about 0.2 μm with increasing grinding cycles. Compared with the ground surface before AJF, friction coefficient and abraded quantity of the surface after AJF are obviously reduced with surface hardness increases gradually-the fact is in conformity with the change in residual stress.