外圆纵向磨削工艺对18CrNiMo7-6钢表面完整性的影响

Effect of cylindrical longitudinal grinding process on surface integrity of 18CrNiMo7-6 steel

为了探究工件转速nw、磨削深度ap和纵向进给速度v_(f)等磨削工艺参数对18CrNiMo7–6钢表面粗糙度和表层残余应力的影响,用端面外圆磨床开展其单因素外圆纵向磨削试验。结果表明:随着nw的增大,工件表面粗糙度R_(a)先减小后增大,当nw为120 r/min时,R_(a)达到最小值,此时工件表面的残余压应力最大;当nw大于120 r/min时,工件表面残余应力出现起伏。随着ap的增大,工件表面粗糙度R_(a)先减小后增大,工件表面残余拉应力随着磨削深度的增大而增大。随着v_(f)的增大,工件表面粗糙度R_(a)先减小后增大,当v_(f)为210 mm/min时,R_(a)值最小;且随v_(f)的增大,工件表面残余压应力逐渐减小,并最终转变为逐渐增大的残余拉应力。

In order to explore the influence of the grinding process parameters on the surface roughness and surface layer residual stress of 18CrNiMo7–6 steel,the cylindrical longitudinal grinding experiment was carried out by using an end cylindrical grinder.With using the workpiece speed nw,grinding depth ap and longitudinal feed speed v_(f),the single-factor experimental research is carried out.The research results show that with the increase of nw,the surface roughness R_(a)of the workpiece decreases first and then increases.When nw is 120 r/min,the surface roughness R_(a)reaches the minimum value,and the surface residual compressive stress value is the largest at this condition,and when nw is greater than 120 r/min,the surface residual stress exists fluctuation.With the increase of ap,the surface roughness R_(a)of the workpiece decreases first and then increases,and the tensile stress influence on the surface layer of the workpiece increases with the increase of the grinding depth.The surface roughness R_(a)first decreases and then increases with the increase of v_(f).When v_(f)is 210 mm/min,the surface roughness value R_(a)is the smallest.With the increase of v_(f),the residual compressive stress of the surface layer gradually decreases and gradually changes to increasing residual tensile stress.