Cubic Boron nitride

Cubic boron nitride (CBN) is a new synthetic material developed in the 1950s. It has high hardness and good wear resistance and is widely used in the mechanical processing industry. Introduction to properties of cubic boron nitride Cubic boron nitride is synthesized from hexagonal boron nitride and catalyst under high temperature and pressure. It is another new product that appeared after the advent of artificial diamond. It has high hardness, thermal stability and chemical inertness, as well as excellent infrared transmission and wide band gap. Its hardness is second only to diamond, but its thermal stability is much higher than that of diamond. Stone has greater chemical stability against iron-based metal elements. The grinding performance of cubic boron nitride abrasive tools is very excellent. It is not only capable of processing difficult-to-grind materials and improves productivity, but also effectively improves the grinding quality of the workpiece. The use of cubic boron nitride is a major contribution to metal processing, leading to revolutionary changes in grinding and the second leap in grinding technology. The hardness of polycrystalline cubic nitriding is very high, reaching 8000~9000HV, second only to the hardness of diamond; the flexural strength and fracture toughness are between cemented carbide and ceramics; the thermal stability is much higher than that of artificial diamond, at 1300℃ It can still be cut, has high oxidation resistance, and does not produce oxidation at 1000°C. The chemical inertness of iron is also much greater than that of artificial diamond, and it is not easy to interact chemically with iron-based materials at high temperatures of 1200 to 1300°C. However, at about 1000°C, it will hydrolyze with water, causing a large amount of CBN to be worn. Therefore, you need to pay attention to the type of cutting fluid when using PCBN tools for wet cutting. Therefore, cubic boron nitride, as a superhard tool material, can be used to process ferrous metals such as steel and iron, especially for processing difficult-to-machine materials such as high-temperature alloys, fire steel and chilled cast iron. It is also very suitable for CNC machine tool processing. Classification The main methods for making cubic boron nitride polycrystalline sintered bodies are: ① Use cubic boron nitride powder and a small amount of binders (such as cobalt, aluminum, titanium and titanium nitride, etc.) at a pressure of 4000 to 8000 MPa and a temperature of 1300 It is sintered at ~1900℃; ② Use cubic boron nitride powder and binder as a layer, cemented carbide (sheet or powder) as a layer, and sinter the two together under the above pressure and temperature to make Polycrystalline sintered body with cemented carbide substrate. This sintered body has high strength while maintaining the original physical and chemical properties of cubic boron nitride. It can be made into discs with a diameter of up to 16 mm and can be cut into appropriate shapes. , as a tool head for turning tools and boring tools, suitable for cutting quenched steel, cast iron and nickel alloys, etc. Application scope The grinding performance of cubic boron nitride abrasive tools is very excellent. It is not only capable of processing difficult-to-grind materials and improves productivity, but also helps to strictly control the shape and dimensional accuracy of the workpiece. It can also effectively improve the grinding quality of the workpiece and significantly improve The surface integrity of the workpiece after grinding is improved, thereby improving the fatigue strength of the part, extending the service life, and increasing reliability. In addition, the cubic boron nitride abrasive production process is better than ordinary abrasive production in terms of energy consumption and environmental pollution. Therefore, expanding the production and application of cubic boron nitride abrasive tools is a mechanical application and an inevitable trend in the development of the machinery industry. 1. Sharpening and rough grinding of tungsten-containing, tungsten-molybdenum-containing and other high-speed steels, especially vanadium alloy steel, cobalt alloy steel, and special high-speed steel tools. 2. Fine grinding and final grinding of precision parts made of heat-resistant steel, stainless steel and high-hardness alloy structural steel. When using ordinary grinding tools for these parts, high accuracy cannot be obtained because the grinding tools are worn out or dulled too quickly. 3. Grinding of various material parts that are sensitive to local thermal stress and thermal shock. 4. Fine grinding and final grinding of large precision workpieces (machine tool guide rails, screws of high-precision machine tools). These workpieces often cause large thermal deformations due to high grinding temperatures, thus failing to achieve high accuracy. 5. Fine grinding and final grinding of mass-produced workpieces (parts of instruments and micro bearings) on automatic and semi-automatic machine tools. 6. Grinding of complex workpieces (gear shaping cutters, broaches, high-precision gears, masters, punches) that require good edge and angle retention. 7. Profile grinding of thread tools and thread gauges (taps, thread rollers, thread plug gauges, etc.). 8. Super finishing of difficult-to-machine heat-resistant steel workpieces. 9. Grinding of other steel quenching tools