| 18MnD5 steel is mainly used in nuclear power equipment because of its excellent mechanical and physical properties such as high strength,high toughness and good hightemperature oxidation resistance.It is an important material for water chamber head.The blank allowance of water chamber head parts is large,which requires multipass and tough cutting.The selection of cutting parameters not only relates to the machining quality and productivity,but also directly affects the service life of tools and machine tools.Therefore,this paper uses the method of combining simulation and experiment to explore its machinability,in order to provide basis for the reasonable selection of cutting parameters.(1)The finite element simulation model of orthogonal cutting is established and verified by experiments.For 18 MnD5 steel,a two-dimensional orthogonal cutting finite element simulation model is established by using J-C constitutive model.The model is used to simulate the cutting force and cutting temperature of 18 MnD5 steel with small cutting parameters.Compared with the measured values of turning experiments under the same parameters,the results show that the model is correct and the simulation results are credible.The tough cutting simulation is carried out by using the model,the temperature distribution and cutting force curve of the cutting area under the condition of tough cutting are obtained,and the influence laws of different cutting parameters on cutting temperature and cutting force are studied.Taking 45 steel as the comparative material,a method combining weight distribution and ratio is proposed to evaluate the machinability of18 MnD5 steel under the condition of tough cutting.(2)The orthogonal cutting experiment of small amount cutting of 18 MnD5 steel is carried out.The cutting temperature and cutting force of the experimental species are recorded by force measuring tool holder and thermal imager.The influence of cutting parameters on cutting temperature is studied,and the empirical formula of cutting force of18 MnD5 steel based on multiple linear regression equation is established.The single factor cutting experiment of 45 steel with the same cutting parameters was carried out,and the cutting temperature was compared with that of 18 MnD5 steel.(3)The machined surface roughness of 18MnD5 steel is measured,the influence law of cutting parameters on the surface roughness of 18 MnD5 steel is explored,and the optimal process combination is obtained;The surface roughness of 45 steel was measured and compared with that of 18 MnD5 steel.The chips produced in the experiments of two materials were collected and their morphology was studied. |
PDF Full Text Request