Simulation And Experimental Study On Temperature Field Of Grinding Rail With New Composite Grinding Wheel

The rail is damaged by the interaction of wheel-rail friction and heavy load and the common forms of damage are wave wear,crack,fat edge and so on.The effective way to remove these damages is to use grinding wheels to grind rails.At present,there are two major problems in rail grinding in China.First,the grinding wheel for rail grinding has poor wear resistance and short life;the second is that the surface of the polished rail is prone to burns.In this paper,the brazed diamond technology is integrated with the existing manufacturing process of zirconium corundum resin grinding wheel for rail grinding for the first time,and a new generation of high performance composite grinding wheel is developed.The temperature field of rail grinding is simulated which is to reduce rail grinding burn.The main work completed in this paper includes:(1)Development of composite grinding wheel.A new composite grinding wheel for rail grinding is fabricated by sheeting brazed diamond sheets into resin zirconium corundum grinding wheel.The 304 stainless steel was selected as the base body.The Ni-Cr alloy brazing filler metal and the 40/45 mesh diamond were brazed with 1028? in a vacuum furnace.The obtained brazing diamond sheet showed high exposure of abrasive grains and the brazing material climbed well.The SEM and EDS were used to analyze the interface of the sheet and it was found that there was element diffusion in the joint surface,which is forming a strong metallurgical bond.(2)Determination of the angle and number of sheet placement.Dynamic simulation and diamond abrasive trajectory are analyzed with Workbench and matlab and the results showed that the uniformity of abrasive trajectory is better when the sheet angle is 45 degrees from the center line.According to the grinding test,the internal stress of the grinding wheel can be reduced and the cracking of the grinding wheel can be prevented when the number of sheets is 8.(3)Composite grinding wheel performance test.According to many field tests of rail grinding,it is found that the new composite grinding wheel can effectively solve the problem of surface burns after rail grinding.A single grinding wheel can grind rail 130 km,which is about 44.4% higher than the domestic resin zirconium corundum grinding wheel.The grinding temperature test was carried out on the rail grinding test machine and the result showed the grinding temperature of the new composite grinding wheel is 8.2% lower than that of the domestic pure resin grinding wheel under 3.6 bar pressure.The reason for the reduction of rail burns is explained by the particularity of the end grinding process.(4)Research on temperature field simulation.The ANSYS software was used to simulate the grinding test temperature.Under different grinding pressures,the error between the simulation results and the test results was about 10%,which verified the reliability of the finite element method simulation.The temperature field of rail turnout grinded by pure resin grinding wheel and new composite grinding wheel is simulated by finite element method with uniform heat source model and triangular heat source model.The simulation results show that under the two heat source models,the grinding temperature of the new composite grinding wheel is about 10% lower than that of the pure resin grinding wheel;the maximum temperature of the surface of the two heat source rails is not much different,but the temperature rise rate of the triangular heat source model is greater than the temperature rise speed of the uniform heat source model;the temperature gradient of the rail grinding exceeds 600 ?/mm.