| 摘要 |
PROBLEM TO BE SOLVED: To obtain a cemented carbide having properties suitable for use in a cutting tool, etc., and excellent in corrosion resistance by incorporating specific percentages of Ni, Co, chromium carbide, and tungsten carbide. SOLUTION: This cemented carbide has a composition which consists of, by weight, 2-6% of Co and Ni, chromium carbide in an amount of 0.1-30% based on Co and Ni, and the balance essentially tungsten carbide and in which the amount of Ni is regulated to 0.4-80% based on the total amount of Co and Ni. Tungsten carbide has a grain size ranging from 0.3 to 5μm. The grain size of tungsten carbide consists of a group of fine grains of 0.3-1.1μm and a group of coarse grains of 1.2-5μm, and the preferred ratio of the amount of tungsten carbide in the coarse grain group to the total amount of tungsten carbide is 0.1-0.9. The wear resistance to machining can be improved to a greater extent by coating the cemented carbide with a Ti compound, such as TiCN, TiC, and TiN, or an oxide, such as alumina, by means of CVD, PVD, etc.
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