Development And Cutting Performance Of Cemented Carbide Tools Toughened And Strengthened By SiCw

As an important tool material,cemented carbide is known as“industrial teeth”for its excellent properties such as high strength,wear resistance,corrosion resistance and hardness,and plays an important role in cutting tools,mining tools and oil exploitation tools.However,the hardness,strength and toughness of traditional cemented carbide tool cannot be optimized at the same time,which is limited in the application of cutting tool at the same time.Therefore,it is especially important to study the high strength and high toughness cemented carbide tool materials.In order to solve this problem,silicon carbide whisker（SiCw）was added to the matrix of cemented carbide to toughen and strengthen it,and the cemented carbide and cutting tools with excellent strength and toughness were successfully prepared.The effects of SiCw content on the microstructure,physical and mechanical properties,friction and wear properties of cemented carbides were investigated,and the effects of SiCw content on the cutting tools made of cemented carbides with excellent properties were also investigated,the excellent performance of cemented carbide was made into tools.And the effects of cutting speed and depth of cut on the cutting performance of cemented carbide tool were investigated.Regenerated cemented carbide tools toughened and reinforced by SiCw were successfully prepared by low pressure sintering process.The experimental results show that the recycled cemented carbide cutting tool material with SiCw content of 0.5wt%has the best comprehensive properties,with density of 14.6g/cm³,hardness of 1575HV,flexure strength of 2204MPa and fracture toughness of 16.85 MPa_·m^1/2.Compared with the regenerated cemented carbide tool material without SiCw,the above properties are improved by 0.7%,14.4%,12.2%and 17.3%respectively.It is proved that the addition of SiCw has a good toughening and strengthening effect on the regenerated cemented carbide materials,because the adding of SiCw restrains the growth of WC grains,refines the grains.It was found that the addition of SiCw changed the fracture mode of the cemented carbide by SEM observation and analysis of the fracture morphology.In that experiment of friction and wear,it is found that the friction coefficient decrease firstly and then increases with the increase of SiCw content when the friction pair is Si₃N₄,and when the content is 0.5 wt%,the friction coefficient and wear amount of cemented carbide materials are lower.The wear mechanism is fatigue wear and oxidation wear.Ti C-based carbide materials toughened and reinforced by SiCw were prepared by vacuum sintering.Compared with the Ti C-based cemented carbide without SiCw addition,the cemented carbide with SiCW content of 0.5wt%addition has the best comprehensive properties.The density,hardness,flexural strength and fracture toughness without SiCw increased by 0.3%,23.5%,26.3%and 19.8%respectively.The observation and analysis by SEM and EDS showed that the presence of Si element was detected in the annular phase of the grains,indicating that a small amount of SiCw was dissolved in the ring phase,which played a role of solid solution strengthening,and also inhibited the growth of Ti C grains.The purpose of grain refinement is achieved.Through the observation of the crack propagation path by SEM,the addition of whisker made the crack deflective,and accompanied with the bridging phenomenon,and the whisker was also observed to pull out holes in the fractograph,which played a role in toughening.At the same time,the addition of whisker changed the fracture mode and further enhanced the comprehensive properties of steel bonded carbide.The friction and wear experimental results show that the greater the load,the greater the friction coefficient.In addition,under the load of 50N and 60N,Ti C-based cemented carbide with 0.5wt%SiCw has the lowest friction coefficient and the best wear resistance,and the wear mechanisms are abrasive wear,adhesive wear and oxidation wear.At last,the cutting experiment was carried out use cemented carbide tools with excellent performance,and the effects of different cutting parameters on the cutting performance of cemented carbide tools were analyzed.The results show that the cutting performance of the tool with two different substrates is the best when the cutting speed is150m/min,the depth of cut is 0.2mm and the feed rate is 0.102 mm/r.After adding SiCw into two kinds of matrix tools,the cutting force and cutting temperature are reduced,the machined surface quality is improved,the service life of the tools is prolonged.