Study On Preparation Of Vitrified Grinding Wheel Using Sol Spray Drying Method

The traditional vitrified grinding wheel using for precision grinding were obtained after mixing, pressing and sintering a few microns to dozens of micrometers of power binder and ultrafine abrasive. The power agglomeration and coarse binder particles made the grinding wheel microstructure coarse and poor uniformity, which made the grinding wheel grinding performance not ideal. This paper used the sol-gel method and spray drying method to prepare the precise grinding wheel, also the relatived technical and theoretical problems were discussed.?1?SiC powders were modified by polyethylene glycol?PEG 20000?. Results show that when the amount of PEG was 5wt%, the uniform dispersion and the best suspension property of the SiC powers were obtioned.?2?R₂O-B2O₃-Al2O₃-Si O₂ multi-component sol bond was prepared by adding Si O₂ sol to Na NO₃, Li NO₃, Al?NO₃?3 and H3BO₃ solution. Results show that after the addition of positively charged electrolyte, the order of the silica sol size was Al3+>Na+>Li+ and the light transmission was Al3+<Na+<Li+; When the temperature was 40?, the multicomponent sol particle size was 281.5nm; The preparation temperature increasing from 40? to 80?, the sol particles grew up to 769.1nm, and the transparency and stability reduced; after sintering at820?, bond glass phase could crystallize nanoscale ?-quartz crystal.?3?Based on the SiC and multicomponent sol bond, spray-drying was used to prepare SiC-vitrified bond composite powders and the process parameters of spray were systematically optimized.Results show that when the spray pressure was 0.10 MPa, the amount of binder was5wt%. The thin film forming by vitrified gel bonded had a complete package of SiC powers and the composite powers were spherical with average particle size of 9.58?m.The density and the repose angles are 0.941g/cm3 and 23° respectively, and the compression molding performance is better.?4?The SiC-vitrified bond composite sintered samples were obtioned after pressing and sintering the powers prepared by sol spray drying method, which were compared with the samples prepared by melting method. At the same time, the grinding performance grinding stainless steel of the samples prepared by two methods was compared. Results show that compared with the sample prepared by the melting method, the bending strength and HRB of sintered samples prepared by sol spraying method were higher and porosity were lower. The microstructure of samples preparedby sol spray drying was more uniform and the vitrified bonder could coat the power more completely. There were no obviously large pores. The grinding roughness of the wheel prepared by sol spray drying method was 0.042, which was lower 78% than the sample prepared by melting method. The surface uniformity of the workpiece after grinding by sol spray drying method was better.