| Titanium alloys represented by TC4 have been widely used in key fields such as national economy,medicine and health,national defense and military industry due to their excellent mechanical properties and biocompatibility.However,due to its poor thermal conductivity,high chemical activity,small elastic modulus and other characteristics,the severe friction in the cutting area,resulting in a larger temperature gradient and high pressure environment and other adverse conditions,will lead to accelerated tool wear.Therefore,higher requirements are put forward for cutting tool materials.However,cemented carbide has always occupied an important position in the cutting tool materials of titanium alloy,and there is a big gap between the quality of high-end cutting tools in China and the imported products,and the substitutability is very low.High-end cutting tools independent technological innovation,and then realize the localization,replace the import is the inevitable trend of China towards manufacturing power.In this context,compared with the redevelopment of high-end tool materials suitable for the cutting of titanium alloy,it is of great significance to find a simple,feasible and economical and environmental friendly cemented carbide treatment method to improve the cutting performance of titanium alloy.Based on the electromagnetic coupling treatment technology,the YG8 carbide turning tool blade was strengthened.By comparing the changes of mechanical properties,friction properties,thermal conductivity and oxidation resistance of YG8 cemented carbide turning tool after electromagnetic coupling treatment and untreated,the influence law of electromagnetic coupling treatment on the physical and chemical properties of YG8 cemented carbide turning tool was analyzed.Then,the physical data of cutting force,cutting temperature,tool durability and surface roughness of titanium alloy workpiece were collected by turning test.The influence law of electromagnetic coupling treatment on the cutting behavior of TC4 titanium alloy by YG8 cemented carbide tool was obtained.Finally,through the mesoscopic research method,the YG8 cemented carbide blade wear was detected,and the influence rule of electromagnetic coupling treatment on the wear form and wear reason of YG8 cemented carbide was obtained.After the above research and analysis,the following conclusions are drawn:(1)The tool durability,cutting force,cutting temperature and workpiece surface roughness of YG8 cemented carbide inserts treated by electromagnetic coupling are improved to varying degrees.In the experimental study of this paper,the Tool with electromagnetic coupling processing parameters of TOOL-2(magnetic field intensity of 1.5T,electric field intensity of 1.2V)has the best performance.Specifically,the Tool rear surface wear decreases by 50%;The average cutting force decreased by 38%;Cutting temperature decreased by 50%;The surface roughness Ra decreased from 6.3 to 1.6.(2)Electromagnetic coupling treatment can significantly reduce the friction coefficient of the rear surface of the YG8 blade and improve the thermal conductivity of the matrix material.The cutting temperature is reduced and the processing environment is improved by reducing the heat generation and changing the heat distribution ratio,increasing the transfer and heat dissipation capacity of the tool matrix.(3)In the oxidation process of YG8 matrix material treated by electromagnetic coupling technology,the pores and other gaps formed in the oxide layer are reduced,and the COWO4 oxide film formed on the surface layer is more compact,which can well prevent the continued infiltration of O2 into the interior of cemented carbide,thus improving its oxidation resistance.(4)The tool wear types of two types of YG8 cemented carbide inserts after electromagnetic coupling treatment and without electromagnetic coupling treatment in turning TC4 titanium alloy include back tool face wear,front tool face wear,boundary wear,micro-chipping edge and surface adhesion.The electromagnetic coupling treatment can effectively reduce the wear forms of YG8 cemented carbide inserts.(5)In the tool stable wear stage: electromagnetic coupling treatment by reducing the cutting temperature,thereby inhibiting diffusion,bonding wear.However,when it comes to the stage of close to severe wear,the cutting temperature rises sharply.At this time,the oxidation resistance of YG8 cemented carbide after electromagnetic coupling treatment is reflected,and the oxidation wear is weakened,but the proportion of diffusion and bonding wear increases. |
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