小切深条件下磨削表面完整性变化机理

磨削表面强化后的残余应力及表面层硬度的改变是评价零件加工表面完整性的重要指标,并对零件的疲劳强度、耐磨损性能等影响显著.针对工程中更为多见的小切深磨削工艺过程,基于45钢试件磨削加工试验,以磨削变质层的金相组织、厚度、表面硬度和残余应力为研究对象,重点讨论了小切深条件下磨削表面变质层组织特征与形成机理.结果表明:在小切深干磨削条件下,工件表层存在残余拉应力,应力值随磨削深度的增加或工件速度的增加而减小;工件表面变质层厚度随磨削深度的增加或工件速度的减小而增大.试验结果说明,在小切深干磨削条件下,合理确定磨削用量及砂轮特性参数等,可使工件表层产生强化作用.

Changing Mechanism of Grinding Surface Integrity Under Small Cutting Depth Conditions

The residual stress and hardness changes of ground surface play the key role in measuring the surface integrity of workpiece,and also have significant effect on the fatigue strength and wear resistance.Concerning grinding process under small cutting depth conditions in practical engineering,based on the grinding strength test of 45 steel specimens,the microstructure,thickness,surface hardness and residual stress of the grinding affected layer were studied.This work highlights the discussions of the formation mechanism and microstructure of the grinding affected layer.The results show that the surface residual tensile stress exists on the workpiece surface after dry grinding at small cutting depth.The residual stress tends to decrease with the increase of cutting depth or workpiece speed.The grinding affected layer thickness tends to increase with the increase of depth of cut or decrease of workpiece speed under small cutting depth conditions.The results indicate that reasonable grinding parameters and grinding wheel parameters can enhance the grinding capacity in dry grinding at small cutting depth.