Study On Preparation And Grinding Property Of Corundum Magnetic Abrasives

Compared with traditional abrasives,abrasive-oriented abrasive tools have the advantages of high grinding efficiency,small grinding force,less thermal diffusivity and good grinding quality.In this paper,corundum-based magnetic abrasive is prepared by Sol-gel method,and the directional arrangement of magnetic abrasive in abrasives is realized by applying directional magnetic field in the process of abrasive forming.And the effects of different sol preparations,surface treatments,coating times and heat treatment temperatures on the microstructure and magnetic properties of magnetic abrasive are systematically studied.By applying well prepared magnetic abrasive materials to the preparation of grinding wheel,the effect of the process parameters on the grinding performance of the grinding wheel is discussed,and the results are as follows:(1)The best preparation process of corundum abrasive film based on Ni ferrite Sol is as follows:pH is 2.2,aging time is 12h-24h,Sol concentration is 3g/600ml.Under the conditions of the process,the Sol particle size can reach 358nm.(2)The surface of abrasive is modified by HF corrosion treatment and KH550 silane coupling agent,and the results show that when using Ni ferrite sol to treat the abrasive film of HF corrosion treatment,the film-forming is better than that of KH550 modified abrasive.The best process for abrasive surface corrosion is:corrosion concentration is 0.5wt%,corrosion time is 1h.And the optimum process for surface modification of abrasive is as follows:the modified concentration is 2wt%and the modified temperature is 60?.(3)The best preparation technology of magnetic abrasive is as follows:the abrasive surface treatment method is HF corrosion,the coating frequency is 2 times,the heat treatment temperature is 800?.At this time,the film layer of magnetic abrasive surface is homogeneous and compact,the impact toughness is declined slightly,and the abrasive failure rate decreases from 68.4%to 64.1%during the heat treatment.Besides,the NiFe2O4 crystal in the film layer tends to be complete,the saturation magnetization is 1.1145emu/g and the coercivity is 85.3G.(4)When the magnetic abrasive is prepared into the resin grinding wheel,the abrasive can be directionally arranged in the grinding wheel.Compared with the ordinary abrasive resin grinding wheel,the hardness and strength of the resin gringing wheel increase from the original 7.67HRB and 15.6MPa to 16.33HRB and 17.92MPa respectively.(5)Using resin grinding wheel to process the bearing of GCr15 steel material,when the feed volume is constant,the surface roundness of the bearing is less changed,and the roughness decreases first and then increases with the increase of the working speed of the grinding wheel;And when the working speed of the grinding wheel is constant,the wear ratio of the grinding wheel decreases,the roundness of the bearing bottom surface increases,and the surface roughness slightly increases as the feed amount increases.Under the same processing parameters,the surface roughness of the outer groove of the machined bearing is reduced from 0.24 ?m to 0.19?m,and the grinding efficiency is improved by 19.1%compared with the ordinary abrasive resin grinding wheel.