Study On Preparation And Performance Of High Speed And Heavy Load High Speed Rail Grinding Resin Wheel

With the rapid development of national railway transportation,the load and running time of passenger,freight and other high-speed trains are also increasing,and the"window period"of rail grinding and maintenance is obviously shortened.How to improve the grinding efficiency and service life of rail grinding tools has become a difficulty.In order to improve the service life and grinding efficiency of zirconium corundum resin grinding wheel,this paper proposes to use modified resin as binder to prepare resin-based superhard composite abrasive and composite it with zirconium corundum abrasive.A new type of zirconium corundum/resin-based superhard composite abrasive wheel is prepared,and the performance of the composite abrasive wheel is adjusted.The main contents of this paper are as follows:F-51 epoxy resin was designed to toughen the high temperature phenolic resin,and the effect of the amount of epoxy resin on the properties of the modified resin was discussed.The curing mechanism and curing power of the modified resin were analyzed by infrared spectroscopy and differential scanning calorimeter,and the thermal properties of the modified resin were tested by thermogravimetric analyzer and dynamic mechanical thermal analyzer.The mechanical properties of the modified resin were tested by electronic universal testing machine and Shaw hardness tester.The test results show that the epoxy/phenolic resin system has good reactivity and compatibility without phase separation,and when the content of epoxy resin is 30 wt%,the curing temperature of the modified resin is 120℃,the bending strength and impact strength of the modified resin are 58.34 MPa and 4.95 kJ/m²,respectively,the hardness,thermal decomposition temperature and glass transition temperature are 90 HD,345℃and 213℃,respectively.Resin-based superhard composite abrasives were prepared by casting molding with epoxy modified phenolic resin as binder,and the preparation process and formula were optimized.The fluidity of composite abrasive slurry is the main factor affecting the forming of composite abrasive.Dibutyl phthalate（DBP）and shaking table are used to adjust the fluidity of composite abrasive slurry.When the dosage of DBP is 6 wt%,and the vibration frequency is 40 Hz,the fluidity of the slurry is good,and the finished product rate of the composite abrasive can reach 98%.The surface treatment and fillers of diamond abrasives have an important influence on the properties of composite abrasives.The impact strength and bending strength of diamond abrasives treated with KH550 can reach 37.13 MPa and 3.10kJ/m²;respectively.When the content of Cr₂O₃ is 8 wt%,the impact strength and bending strength of composite abrasives are the highest,which can reach 41.92 MPa and 3.51 kJ/m²,and the compressive strength can reach 78.2 MPa.When the content of Cu powder is 6 wt%,the impact strength,bending strength and compressive strength of composite abrasives are the highest,which can reach 48.73 MPa,4.12 kJ/m² and 96.2 MPa,respectively.By compounding resin-based superhard composite abrasive with zirconium corundum,zirconium corundum/resin-based superhard composite abrasive grinding wheel was prepared,and the formula of composite abrasive grinding wheel was designed.The performance of composite abrasive grinding wheel is tested by using universal testing machine and high-speed passive grinding platform.The surface morphology of rail workpiece was observed and analyzed by ultra-depth-of-field microscope and white light interferometer.The test results show that when the amount of composite abrasive is 20%of the volume fraction of abrasive,the bending strength,impact strength,grinding efficiency and grinding ratio of the composite abrasive grinding wheel are the highest,which can reach 31.2 MPa,2.71 kJ/m²,118 mg/s and 12.6 respectively,and the surface roughness of the polished rail can reach 1.41μm.When the amount of resin binder is 42 vol%,the grinding ratio of composite abrasive grinding wheel can reach 15.3.Based on the laboratory research,the road tests of the composite abrasive grinding wheel and the imported zirconium corundum grinding wheel are carried out through the high-speed rail grinding train.The results show that the average durability of the composite abrasive grinding wheel can reach 1.6 km/mm,which is 52%higher than that of the imported zirconium corundum grinding wheel.Zirconium corundum/resin-based superhard abrasive grinding wheel can greatly improve the service life of rail grinding wheel,which provides an important theoretical basis for domestic rail grinding wheel to replace imported grinding wheel.