The hottest special ceramic tool materials

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Special ceramic tool materials (Part 2)

6. Boron nitride ceramic tools: Recently, Sumitomo Electric Company of Japan developed a ceramic tool material with higher hardness, adhesive cubic boron nitride ceramic (CBN) sintered body. The sintered material was sintered at 780pa at 2300 ~ 2400 ℃ for 10 minutes. This technology also includes unique software technology such as grinding the diameter of micro powder to improve the purity of CBN in the raw material preparation stage. The sintered boron nitride ceramic material with CBN content of 100% is developed by combining particles with particle size less than 0.5mm

the ceramic tool made of boron nitride material will not cause common thermal cracking and chip loss at the head end of the tool when cutting cast iron with high hardness. According to different conditions, compared with CBN sintered body containing other bonding materials, the service time of boron nitride ceramic tool high molecular chain in natural crimping state without external force can be extended by more than 10 times, becoming a material that can be used for intermittent cutting. Especially in the processing of automobile industry, hBN sintered body, as a cutting material that can process hard cast iron materials such as engines, has a wide range of applications in machining

the previous sintered body cannot form unique properties such as high hardness and thermal conductivity as cBN because it contains granular binder. For example, CBN direct conversion technology is not suitable for high-speed cutting tools because its particle size is too coarse when using a small gate

7. Silicon nitride ceramic tools: silicon nitride ceramic tools have physical properties of low density, high strength and high hardness. Its room temperature hardness value has exceeded the hardness of the best cemented carbide tool, which greatly improves its cutting ability and wear resistance. Manual measurement can be processed, that is, one scale and two horizontal distance rods that can be moved in the vertical direction are vertically set beside the moving rod of the fixture. All kinds of hard steel and hardened cast iron with high hardness. Its bending strength has exceeded the high-speed profile and is equivalent to that of ordinary cemented carbide. The fracture toughness of silicon nitride ceramic tools is 6 ~ 7mpavm higher than that of other series tools. The thermal resistance index of silicon nitride ceramic tools is as high as 600 ~ 800 ℃, which is obviously superior to other series of ceramic tools (300 ~ 400 ℃), and its cutting speed is 3 ~ 10 times higher than that of cemented carbide tools. Therefore, it shows its superior performance in the processing of high-strength intermittent parts

silicon nitride ceramic tools include: pure silicon nitride ceramic tools and silicon nitride composite ceramic tools

① pure silicon nitride ceramic tool has hardness hra91 ~ 92, bending strength 700 ~ 900MPa, fracture toughness 4.2 ~ 5.2mpavm, heat resistance 1300 ~ 1400 ℃, thermal expansion coefficient 3.0/℃, and good oxidation resistance. ② Silicon nitride composite ceramic tool; It is a ceramic tool made by adding Al2O3, Y2O3, tic, tin, MgO and other components to the silicon nitride matrix, using the composite strengthening effect and cold pressing and sintering. Its performance is better than that of hot pressed pure silicon nitride ceramic tools

for example, the ceramic tool sintered with Al2O3 added to silicon nitride has the characteristics of Al2O3 and SiN4. Its thermal hardness is higher than that of cemented carbide tool and alumina ceramic tool. The tool tip temperature is higher than 1000 ℃, and it can still be cut normally at high speed. Its biggest advantage is to improve the cutting speed, increase the feed rate, improve the metal removal rate, and extend the tool life. Silicon nitride ceramic cutting tools are especially suitable for cutting various cast iron and superalloys, but they cannot process steel that produces long chips

in a word, with the deepening of research and development of special ceramic materials, the application proportion of ceramic tools in metal cutting and processing industry continues to expand. With the development of aerospace industry, it is necessary to meet the requirements of improving the cutting efficiency of workpiece materials such as Ti alloy and Ni base superalloy. Special ceramic tool materials will make greater contributions

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