Superhard Tools Come Of Age
At present, the world’s known material, diamond the hardest two kinds of cubic boron nitride material. Because of their hardness, much more than other materials several times, thus reducing these two kinds of materials known as super-hard material. Diamond due to superior performance, applications continue to expand, from the metal processing developed into an optical glass processing, stone processing, ceramic processing, traditional processing hard and brittle materials, processing is difficult to field a variety of industrial development will play a significant role in promoting, diamond Tool enjoy broad prospects.
Overview
Superhard cutting tool materials, ceramic materials that is more rigid than the tool material. Including: single-crystal diamond, polycrystalline diamond (PCD), polycrystalline cubic boron nitride (PCBN) CVD diamond and so on. Superhard cubic boron nitride cutting tools mainly diamond cutting tools for the material, which in order to man-made diamond compound piece (PCD) and cubic boron nitride cutting tools composite films (PCBN) cutting tools are dominant. Many cutting concepts, such as green processing to vehicles on behalf of the grinding, in order to milling on behalf of the grinding, hard-state processing, high-speed cutting, dry cutting and so on because of superhard cutting tool application of the sky, so superhard cutting tool has become indispensable to the important手段. As technology advances, manufacturing high-speed development, CNC machining technology, the rapid development and widespread use of CNC machine tools, production and application of super-hard cutting tools are increasingly being used. PCDPCBN machining tool has been widely used in various industries, such as auto parts machining, laminate flooring and processing, which greatly facilitated the cutting and the rapid development of advanced manufacturing technology
Diamond, superhard materials, properties and role of the
As we all know, diamond material composition of carbon, diamond and iron-based pro-edge, cutting process, diamond is superior thermal conductivity, heat quickly, but pay attention to cutting heat should not be higher than 700 degrees, otherwise the graphite phenomenon occurs, the tool will quickly wear. Because of diamond under high temperature and W, Ta, Ti, Zr, Fe, Ni, Co, Mn, Cr, Pt and so will react with ferrous metals (iron-carbon alloy) processing would be a chemical wear, therefore, not be used for processing of a black diamond can only use non-ferrous metals non-metallic materials, while the CBN even 1000oC high temperatures, cutting of ferrous metals are completely competent. Has become difficult to machine materials the next major cutting tool materials. Superhard materials, generally refers to man-made diamonds, man-made CBN. At the same time keeping the two materials has played a complementary role, can cover current and future development of new types of materials processing on the entire cutting area of favor.
1. PCD
Sintered diamond compacts (PCD) appears in many ways to replace a natural single crystal diamond. PCD and natural diamond comparison, inexpensive, and easy sharpening than natural diamond, so its application to promote the particularly rapid. A large number of emerging new materials, the majority is immune processing of materials, such as high-silicon aluminum alloy, automobile engine piston extensive use of such material. General, less than 10% silicon content aluminum alloy, carbide cutting tools can be used, but more than 10% silicon content, it can only be with PCD. Current high-silicon aluminum alloy Si-volume 12% or more, of 18% or more, it is none other than the non-PCD.
However, due to many types of PCD, there is need for a reasonable choice. Its particle size and concentration will affect the hardness and wear resistance properties. Therefore, the application must be processed according to the types of materials. Hardness of features to consider any reasonable parameters. PCD production has been very popular at home and abroad, but the quality is quite different, so prices differ significantly.
2. PCBN
Cubic boron nitride sintered body (PCBN) CBN particles sintered together with the binder, hardness only to diamond, and black metal-free pro-power. However, PCBN generally not suitable for cutting steel. PCBN tool material properties are as follows:
(1) has a high hardness wear resistance.
CBN and diamond crystal structure is similar to the same type of chemical bond, lattice constants are similar, and therefore has similar hardness and strength of diamond. CBN Micro powder shadow degrees HV8000-9000, its sintered PCBN hardness of HV3000-5000.
(2) has a high thermal stability.
CBN heat-resistant up to 1400-1500 ℃, PCBN800 ℃ when the hardness is also higher than the room temperature hardness of ceramic alloy.
(3) has excellent chemical stability.
Because PCBN temperature, atmospheric water vapor, 900 ℃ the following without any change and stability, even at 1300 ℃, Fe, Ni, Co, also almost no reaction, but not as sharp as diamond wear and tear, then it can still maintain a hard quality alloy hardness, therefore, it can not only cutting off hardened steel parts or chilled cast iron, and can be widely used in high-speed or super high-speed cutting work.
(4) has good thermal conductivity.
Various types of tool materials, CBN thermal conductivity second only to diamond, much higher than the carbide, and along with temperature, PCBN thermal conductivity increases.
(5) has a better friction coefficient.
Materials with different coefficient of friction between the CBN for the 0.1-0.3, carbide of 0.4-0.6, with the cutting speed increased, the friction coefficient.
I am China Computer Parts writer, reports some information about plastic blasting media , boron carbide.
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