Research On The Test Of Experimental Simulation Of Rail Milling & Grinding And Cutting Performance

To ensure the safety of railway transportation,rail defects need removing in time.Rail milling train is a kind of on-site rail maintenance device with a combination of form milling cutter and form grinding wheel.Large cutting force and high cutting temperature are generated in the milling-grinding operation,which can easily cause cutting tool wear and reduce millinggrinding maintenance efficiency and even burn the rail material.With the rapid development of domestic railway construction,there is more demand for rail milling trains.Therefore,it is necessary to make some key achievements in rail milling-grinding technology to break the foreign monopoly.Based on rail milling-grinding maintenance,a special milling-grinding experimental platform is established to improve the wearing conditions and enhance maintenance efficiency and prevent the over burning of rails.Research on the cutting force and cutting temperature involved in the processing of the milling-grinding operation is performed.The main contents are as follows:(1)U71Mn(60kg/m)rail steel is chosen as the research object.Basic mechanical tests are conducted to master the properties of the studied material.Subsequently,the cutting tools materials and geometry parameters used for machining rails.Furthermore,the material and the grain size of the grinding wheel are selected.(2)Based on the fundamentals of rail milling-grinding maintenance,,a special millinggrinding platform which encompasses the measurement system of cutting force and temperature is built as per the actual application working conditions of rail milling-grinding.More emphasis is laid on the design of milling cutter and grinding wheel which are the main parts of the project to simulate one-time form milling-grinding of rails.Also,the cutting force and cutting temperature can be monitored on line effectively.(3)Simulation tests of rail milling-grinding are carried out and cutting force is monitored to command its changing rules.It reveals that the milling force decreases with the increase of milling speed and increases with the increase of milling width and feed per tooth;grinding force decreases with the rise of grinding speed and increases with the increase of grinding speed and the grinding depth.Combined with orthogonal method,the milling force and grinding force models are built.F-test is used to verify the linear correlation and cutting parameters are optimized by range analysis.(4)Based on line heat source method,the temperature field of rail form milling and form grinding are established,respectively.The integral temperature model of milling-grinding operation is calculated by the superposition of temperature fields.Experiments are conducted to demonstrate the validity of the model.The effects of milling-grinding parameters on the rail surface temperature by virtue of this model.It shows that the temperature on the rail surface increases with the increment milling and grinding speed as well as milling or grinding depth,and the effect of feeding speed on the increase of temperature is not that conspicuous.