This article focuses on the advantages and disadvantages of using cobalt- and tungsten-based metal bonds in the manufacture of production honing sticks.
Metal binders mainly include cobalt-based copper-based, iron-based, nickel-based tungsten-based, aluminum-based, and so on.
▶ The higher price of cobalt makes the production cost of abrasive tools high.
▶ Iron and cobalt belong to the same family of elements, with similar properties and low prices. At present, there are many types of research on replacing cobalt with iron, but when the iron content is more than 40%, the binder is very sensitive to the sintering temperature, and it is easy to underburn and excessively erode diamond.
▶ The aluminum-based binder has a low sintering temperature and is considered to be an ideal energy-saving binder. Adding an appropriate amount of SC, B, C, or electric furnace alumina abrasives to aluminum-based alloys can greatly improve the hardness of aluminum-based alloys and the wear resistance of diamond tools without increasing the melting point.
▶ Tungsten base actually uses tungsten and tungsten carbide base matrix as geological drill grinding blocks and cutting saw blades with strong abrasive materials, such as cement pavement expansion joint cutting blades, and the use effect is very good.
Advantages of Co in binders:
①Cobalt has high flexural strength, and cobalt can also improve the flexural strength of copper-based matrix.
②Cobalt is easy to wear, or cobalt has moderate wear performance, which greatly improves the comprehensive cutting performance.
③Cobalt has a lower contact angle and larger adhesion work for carbon materials and framework materials, which is slightly lower than that of iron and nickel, that is, it has a larger affinity with diamond.
④Compared with nickel, the presence of cobalt is conducive to the formation of WC, and cobalt and tungsten can also form M6C-type carbides with diamond.
⑤ Cobalt and cobalt-based matrix have small deformability (small degree of tolerance), which improves the quality of cutting and grinding.
⑥Reduced cobalt powder has good sinterability and good formability, and is suitable for laser welding sheets.
⑦Due to the easy wear properties and small deformation of cobalt, pure drill and cobalt-based tools are more broad-spectrum.
Disadvantages of Co:
The price is expensive, and the pine ratio is too small and must be granulated.
Advantages of W in binders:
①It has good compatibility with iron, copper, diamond and nickel.
② Tungsten can react with diamond on the surface of diamond to generate carbide. The thermodynamic conditions for the reaction are not harsh, and carbides are generated above 750 °C.
③The WC generated on the diamond surface cannot be boiled off with acid, and graphitization does not occur on the diamond surface.
④Increase the wear resistance of the carcass and reduce the deformation.
Disadvantages of W:
The porosity of the sintered billet is large; to achieve the designed density, the temperature and pressure must be increased, and the energy consumption needs to be increased.
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---EDITOR: Anna Wang/Cynthia Lee
---POST: Cynthia Lee