Study On Mechanism And Simulation During High Speed Machining Of Ultra High Strength40CrNi2Si2MoVA

With the rapid development of aeronautics, astronautics, automobile, energyetc, the ultra high strength steel40CrNi2Si2MoVA, as a new kind ofdifficult-to-cuting material, was widely applied to fields of aeronautics andastronautics. However, the difficult and low efficiency in processing severelyrestricted the application and development of this material in fields of aeronauticsand astronautics. The unique mechanical properties of this material made itpresent big cutting force, high cutting temperature, serious wear of the cuttingtools, poor quality of machined surface and difficult controlling of chip etc,therefore, it is a challenge in cutting and processing field to realize efficientcutting and processing. In this paper, we utilized the method of combination ofexperiment and finite element simulation to research the cutting force, cuttingtemperature and chip of the ultra high strength steel40CrNi2Si2MoVA based onthe theory of high speed cutting.Firstly of all, through the theory analysis of the cutting force and cuttingtemperature, single factor cutting experiment was carried out to research theinfluence of the cemented carbide, ceramic cutting tool and PCBN cutting tool onthe cutting process in different cutting parameters, respectively. According to thecomparison of cutting tool properties and the experiment data, we choose PCBNcutting tool to research the influence rule of the three elements of cuttingparameters and the cutting tool nose radius on the cutting force and cuttingtemperature, respectively. The mathematical model of PCBN cutting tool cutting40CrNi2Si2MoVA steel in the cutting force and cutting temperature wasestablished by adopting three factors-four levels orthogonal cutting experiment.Besides, the cutting parameters affecting primary and secondary factors of the cutting force and cutting temperature was observed by using poor analysis andthe cutting parameters was optimized by using mathematical fuzzy algorithm.Secondly, based on the analysis of the chip of the ultra high strength steel40CrNi2Si2MoVA, we carried out the chip breaker test of40CrNi2Si2MoVAsteel with six kinds of cutting speed by using carbide groove cutting tools,reseached the influence rule of cutting parameters on chip break, established themathematical model of between cutting speed and chip breaker points, the criticalfeed rate, the critical depth of cut, analysed the impact of different cuttingparameters on chip macro morphology and microstructure and summarized theinfluence factors of chip breaking and its control method.Finally, the PCBN cutting tool cutting ultra-high strength steel40CrNi2Si2MoVA finite element simulation model was established by utilizingAdvantedged finite element analysis software. Through the comparison of thesimulation result of the cutting force, cutting temperature and chip with cuttingexperiment data, we verified the validity of the finite element cutting model,declaring the simulation model could replace part of the experiments to furtheranalyze the influence rule of tool geometric parameters and cutting parameters onchip formation, cutting force, cutting temperature, stress and strain,etc.