淬硬工具钢内圆表面磁性研磨加工实践与研究

INNER SURFACE MACHINING OF QUENCHED TOOL STEEL BY MAGNETIC ABRASIVE METHOD

磁性磨料研磨是一种较新的光整加工的方法 ,它是在S、N两极之间加入磁性磨料 ,磁性磨料吸附在磁极和工件表面上 ,并沿磁力线方向排列成有一定柔性的“磨料刷” ,工件一边旋转 ,一边做轴向振动 ,以达到去除表层金属的目的 ,使工件表面粗糙度大大下降。本文介绍了磁性磨料研磨的加工原理 ,对工件在磁场中的受力情况进行理论分析。对淬硬工具钢 (T8A)工件内圆表面进行磁性磨料研磨的加工试验 ,得出了不同的磁感应强度 ,不同加工间隙 ,以及不同研磨时间对加工表面粗糙度和研磨量的影响 ;从而得出了优化的磁性磨料研磨的加工参数 :磁感应强度B =1.0～ 1.2T ;加工间隙Δ =1～ 3mm ;研磨时间t =4～ 5min。

Magnetic abrasive machining is a newly developed technology for superfinish machining during the latest decade. The magnetic abrasive materials are put into the space between S-pole and N-pole, which, attracted by the S and N poles and adsorbed onto the workpiece, form a flexible 'abrasive material brush' along the direction of the magnetic line of force. Under this condition the workpiece rotates and oscillates simultaneously, thereby the burrs will be abraded and the superficial finish will be greatly improved. In this paper the principle of magnetic abrasive machining is introduced; the stress analysis of the workpiece in the magnetic field is given. By the experiment of magnetic abrasive machining on inner surface of quenched tool steel (T8A), some technical findings had been achieved. The material removal and the roughness of the machined parts vary with the duration of grinding, magnetic induction strength and machining clearance. The optimum parameters of magnetic abrasive machining for internal surface are summarized as: magnetic induction strength B=1.0～1.2T;machining clearance Δ=1～3mm;the duration of grinding t=4～5min.