Finite Element Simulation Analysis And Cutting Performance Research Of B₄C-TiB₂-SiC Ceramic Tools

With the development of modern intelligent manufacturing industry,superhard and difficult-to-cut materials continue to emerge,to the extent that traditional alloy cutting tools can no longer meet the requirements of modern high-speed turning for high precision,high efficiency,and high stability.Developing new material tools has become an important task in the field of turning.Ceramic materials have ultra-high hardness and excellent high-temperature and wear resistance,and are considered a very promising tool material.In this paper,a B₄C-TiB₂-SiC ternary composite ceramic cutting tool was prepared,and AISI 4340 round bar（40CrNiMo alloy structural steel）was used as the application background to study the B₄C-TiB₂-SiC ceramic cutting tool through finite element simulation analysis combined with turning experiments.In this thesis,B₄C-TiB₂-SiC ternary composite ceramic cutting tool was prepared and used to cut AISI4340 round bar（40CrNiMo alloy structural steel）as the application background.The B₄C-TiB₂-SiC ceramic cutting tool was studied by finite element simulation and turning experiment.Firstly,B₄C-30vol.%TiB₂-10vol.%SiC and B₄C-30vol.%TiB₂composite ceramics were successfully prepared using hot-pressing sintering technology,and the influence of SiC addition on the microstructure and mechanical properties of B₄C-TiB₂-based composite ceramics was thoroughly investigated.After the addition of SiC additive,the fracture toughness,thermal conductivity,and relative density of B₄C-TiB₂-SiC composite ceramics were greatly improved,while other properties showed little difference.Then,a simulation cutting model was constructed in DEFORM-3D software.The simulation results showed that cutting depth was the most significant factor affecting tool temperature and main cutting force.For the main cutting force,cutting depth was also the most influential factor.The influence of cutting parameters on the main cutting force was greater than that on the tool temperature.Therefore,when determining the optimal cutting parameters,the variation of the main cutting force should be given priority.The final optimal cutting parameters for B₄C-TiB₂-SiC ceramic tool were:feed rate of 0.1mm/r,cutting depth of 0.3mm,and cutting speed of 300m/min.Finally,the cutting experiment of AISI 4340 round bar with B₄C-TiB₂-SiC ceramic cutting tool was carried out.The experimental results show that both the simulated chip and the experimental chip are banded chips,which indicates that the simulation process can highly restore the real cutting process,and proves the accuracy of the simulation model.When the wear amount（VB）on the rear cutting edge reaches the failure criterion of the tool（VB=400μm）,the cutting length（L）of the B₄C-TiB₂-SiC tool is21%and 32.9%longer than that of the B₄C-TiB₂and YD tools,respectively,indicating that the B₄C-TiB₂-SiC tool has the longest service life.Compared with the B₄C-TiB₂tool,the B₄C-TiB₂-SiC tool can achieve higher surface processing quality.The addition of SiC in B₄C-TiB₂improves the oxidation resistance of the B₄C-TiB₂-SiC composite ceramic without reducing the hardness of B₄C-TiB₂,which is beneficial to the cutting performance of the tool.The wear mechanism of B₄C-TiB₂SiC ceramic cutting tool wear is abrasive,adhesive,oxidative,and diffusion wear.