The application prospect of the hottest superhard

2022-08-01
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Superhard cutting tool materials have broad application prospects

superhard cutting tool 10. The machine calibration is simple. The development of materials

superhard cutting tool materials refer to natural diamonds and artificial diamonds and CBN (cubic boron nitride) with similar hardness and performance to achieve the purpose of sand fixation. Due to the high price of natural diamond, Artificial Polycrystalline Diamond (PCD), polycrystalline cubic boron nitride (PCBN) and their composites are mostly used in production

as early as the 1950s, the United States used artificial diamond powder and artificial CBN powder to form large polycrystalline blocks as tool materials under the action of high temperature, high pressure, catalyst and binder. After that, DeBeers of South Africa, the former Soviet Union and Japan also successfully developed it. In the early 1970s, the composite sheets of diamond or CBN and cemented carbide were introduced. They were made by sintering or pressing a layer of 0.5mm ~ 1mm PCD or PCBN on the cemented carbide matrix, thus solving the problems of low bending strength of superhard tool materials and difficult inlaying and welding, and making the application of superhard tools into the practical stage. At present, functional materials such as synthetic large single crystal diamond, diamond film coating and diamond thick film prepared by CVD (chemical vapor deposition) method have emerged, which has greatly broadened the application field of over range protective materials for superhard tool materials

the research and application of superhard tool materials in China began in the 1970s. In 1970, the sixth grinding wheel factory, the first professional manufacturer of superhard materials and products in China, was built in Guiyang. In the 20 years from 1970 to 1990, the annual output of superhard materials only increased from 460000 carats to 35million carats. Around the 1990s, many specialized factories for superhard material production introduced complete sets of superhard material synthesis equipment and technology from abroad, and the output has developed rapidly. By 1997, the annual output of artificial diamond in China had reached about 500million carats, and the annual output of CBN reached 8million carats, ranking first in the world in superhard material production

properties of superhard tool materials

diamond has extremely high hardness and wear resistance. Its microhardness can reach 10000hv. It is the hardest tool material. At the same time, its friction coefficient is small, it has no affinity with non-ferrous metals, the chips are easy to flow out, the thermal conductivity is high, it is not easy to produce chip nodules during cutting, and the machining surface quality is good. It can effectively process non-ferrous metal materials and non-metallic materials, such as copper, aluminum and other non-ferrous metals and their alloys, ceramics, non sintered cemented carbide, various fiber and particle reinforced composite materials, plastics, rubber, graphite, glass and various wear-resistant wood (especially composite materials such as solid wood and plywood)

the disadvantages of diamond are poor toughness and low thermal stability. It is easy to carbonize at 700 ℃ ~ 800 ℃, so it is not suitable for processing. Therefore, the research on the reinforcement, toughening and cost of aerogel has become the key to its wide use in the field of building energy conservation as a high-performance light transmission and heat insulation material. Because at high temperature, iron atoms are easy to interact with carbon atoms to convert them into graphite structure. In addition, when it is used to cut nickel base alloys, it will also wear rapidly

cbn is second only to diamond in hardness (up to 8000hv ~ 9000hv), with high thermal stability (up to 1250 ℃ ~ 1350 ℃), great chemical inertia to iron group elements, strong anti bonding ability, and can be grinded by diamond grinding wheel. Therefore, it is suitable for processing all kinds of hardened steel, thermal spraying materials, chilled cast iron, cobalt based and nickel based materials above 35hrc

superhard tool material has broad application prospects

superhard tool material is an advanced tool material, which has broad application prospects in production. At present, the development of artificial superhard tool materials is towards coarse grain, high strength and multi-function. GE company of the United States can now produce 6 carat artificial diamond (about 10mm) in industry, with the maximum particle weight of 11.14 carat. PCD is developing in the direction of large diameter, fine grain, high impact resistance and high thermal stability

pcd has a maximum diameter of 74mm, and then it is cut into any desired shape by laser. The commodity size of PCD particles is 2 ~ 25 m; The finer the particle, the better the quality of the cutting edge; The larger the particle, the longer the tool life. PCBN products produced by DeBeers company have a maximum diameter of 101.6mm and can process high hardness materials of 70hrc. In addition, according to the British patent, the UK has also developed a CVD method to deposit a layer of mixture of nickel, copper, titanium, cobalt, chromium and tantalum on the outer surface of PCD and PCBN blades, as well as a protective coating of titanium nitride or titanium carbide. Its wear resistance can be 4 times higher than that of ordinary PCD and PCBN blades

cvd diamond films and thick films are newly developed functional materials in recent years. Although the production has not yet formed a scale, they are widely used because of their excellent properties

natural and synthetic single crystal diamonds, as well as PCD and TFD, have overlapping application fields. To a certain extent, they can complement each other. They must be selected according to different specific conditions, especially the performance price ratio. It is expected that in the new century, the superhard tool materials CBN and diamond will be more applied, and it may be found that new types of tool materials with better performance will be manufactured. According to the introduction of lelland company, they have developed a super hard composite material composed of ceramic and CBN. It has the advantages of both ceramic and CBN materials, and is an ideal material for high-speed machining of high hardness and wear-resistant cast iron. For another example, the polycrystalline diamond synthesized from graphite is C12. It has been studied that the isotopes C13 and C60 are harder. A few years ago, Wuhan University developed a c3n4/tin film, which also has superhard material properties. Coating it on high-speed steel drill bits can greatly improve the service life of drill bits. It can be expected that with the increasing application of various new difficult cutting materials in the future, it will promote the further development and application of superhard tool materials

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