Study On Cutting Heat Conduction And Cutting Performance Of Coated Tools

Spraying coating on the matrix of the carbide inserts can effectively improve the cutting performance of the cutters and reduce tool wear during tool cutting process and prolong the life of the cutters.Coating technology has become a common technology in the field of metal cutting.The influence of tool coating on heat conduction in the cutting process has always been the focus of research in the field of cutting.In this thesis,TiAlN coated and TiCN+Al₂O₃+TiN coated tools are selected as the research objects,the cutting heat and thermal contact resistance of H13 steel with coated tools are studied.The heat source model,chip temperature rise model and tool temperature model are established respectively.The change of cutting temperature and cutting heat distribution coefficient is discussed.Fluent software is employed to simulate the thermal resistance between the contact surfaces under different contact areas.The change of the contact thermal resistance with the contact area between the contact surfaces is discussed.The influence of heat source temperature and contact area on contact thermal resistance are studied by simulation test.The experiment of cutting H13 steel with TiAlN coated and TiCN+Al₂O₃+TiN coated tool are carried out.The change of cutting force and cutting temperature of two kinds of coating materials and cutting parameters is compared.The friction coefficients of two kinds of coated tools and H13 steel is obtained.The tool life and wear breaking mechanism of the coated tools are analyzed.The front heat distribution model and the temperature rise model are also verified and studied.The contents are as follows:?1?The mathematic analysis method is used to calculate the heat partition coefficient of the tool-chip interface and the maximum temperature on the rake face during the cutting process.The heat generation of the TiAlN coating and the TiCN+Al₂O₃+TiN coated tool in the second deformation zone at different cutting speeds are studied.The effect of cutting speed on the heat partition coefficient is analyzed.The heat distribution coefficient increases with the increase of cutting speed,that is,the higher the cutting speed is,the more heat the incoming chip will be.The rake face of the highest temperature and heat distribution coefficient and the change trend,with the increase of cutting speed increases continuously.?2?Throughout the mathematical analysis and finite element simulation,the relationship between the contact surface contact area of the contact surface and the contact surface of the contact surface is discussed.With the decrease of the actual contact area of the chip,the contact thermal resistance increases gradually,which shows that the decrease of the heat partition in the tool is reduced with the reduction of the actual contact area of the chip.The influence of external heating power,contact area and solid surface medium on contact thermal resistance is studied through simulation test.It is concluded that the heating power voltage has little influence on contact thermal resistance,and the compensation temperature has little influence on contact thermal resistance,and the contact area has a great influence on contact thermal resistance.?3?The friction coefficient of the TiAlN and TiCN+Al₂O₃+TiN coated tools and the hardened H13 steel is measured under dry friction test.The friction coefficients of the two kinds of friction pairs are 0.41 and 0.72,respectively.Through the cutting tests of two kinds of coated cutting tools,it is found that the cutting forces of the three directions increases with the cutting parameters,the trend of tangential force and radial force is similar,and the trend of axial force increasing is the smallest.The cutting temperature increased with the increasing of cutting parameters.The cutting temperature of the two kinds of coated tools is compared with that of the front temperature rise model and the heat distribution model.