| The working environment of high temperature hot end parts such as marine gas valves is harsh.In order to ensure its stable operation,it is required to have excellent corrosion resistance,mechanical properties and thermochemical stability.Nickel-based superalloy Inconel718 can still maintain excellent comprehensive mechanical properties under high temperature conditions,so it is widely used as the manufacturing material of gas valves.However,Inconel718 not only has excellent working performance but also has the disadvantage of low machinability.In actual cutting production,there are many phenomena such as high cutting force,high cutting temperature,serious tool wear and poor surface forming quality.For a long time,enterprises often set cutting parameters by experience in actual production,which has blindness and randomness.Therefore,scientific methods are needed to optimize cutting parameters reasonably.Compared with the traditional experimental method,the numerical simulation research method is more efficient and economical,and many state variables which are difficult to measure directly or can not be obtained from in cutting experiments can be obtained from the simulation results.In this thesis,the cutting finite element simulation theory and key technologies are studied,and the finite element model of turning of high temperature resistant materials for marine gas valves is established and the subsequent research is carried out on this basis.In this thesis,the effects of tool geometry Angle and cutting amount on the turning process are analyzed by a single factor comparative simulation experiment.By analyzing the distribution and change rule of cutting force,cutting temperature and other physical parameters,the relevant conclusions are drawn and determined that the cutting performance and machining effect of the cutting edge with 5°rake angle,9°clearance angle and 0.06 mm cutting edge roundness are the best within the scope of the study.Cutting force and cutting temperature are two very intuitive and important physical quantities in metal cutting process,which directly affect the machining quality and tool life.In actual production,cutting parameter often changes at the same time,and their influence on cutting force and cutting temperature is very complex and there is a quadratic effect.In order to further clarify their relationship,the prediction model of cutting force and cutting temperature on the three elements of cutting parameters was established based on the data of simulation experiment with response surface method by using Design-Expert software,and the influence and degree of each factor on the response value were analysed through variance analysis.Finally,in accordance with the actual production of high efficiency,high quality and low cost,using multi-objective genetic algorithm,with the minimum cutting force,the minimum cutting temperature and tool life longest,maximum material removal rate and the minimum surface roughness sugar as the goal,set up the optimization model of cutting parameters and to find the solution through the MATLAB platform.Multiple optimal combinations of cutting parameters and corresponding objective function values are obtained and the reliability of the optimization results was verified by simulation,then you just have to choose from them according to the actual needs.The research of this topic will provide some reference for the study of finite element simulation of metal cutting process,and provide a solution for the formulation and optimization of process parameters in the actual turning of marine gas valve high temperature resistant materials.It has important engineering application value and far-reaching significance for further study and improvement of cutting mechanism of nickel-based superalloy,scientific and effective optimization of cutting process parameters and improvement of cutting quality and economy. |
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