| 摘要 |
PROBLEM TO BE SOLVED: To provide the cemented carbide which is high in hardness, high in strength and excellent in toughness by providing the cemented carbide having the composition of the bonded layer mainly consisting of VN, Cr2 N, N, and Co of the prescribed wt.%, and the balance WC, and specifying the mean grain size of WC particles. SOLUTION: The WC-Co ultra-fine cemented carbide has the composition consisting of, by weight, 0.05-0.50% VN, 0.50-1.00% Cr2 N, 5-20% bonded layer mainly consisting of Co, and the balance WC with inevitable impurities. The mean gain size of WC particles in the alloy is <=1.0μm. The content of nitrogen in the alloy is 0.05-0.20%. The weight ratio of V/Cr contained in the alloy is 0.05-0.5. In manufacturing the alloy by the powder metallurgy method, the green compact of the raw powder sintered in the atmosphere of nitrogen partial pressure of 600-760 Torr. in the temperature range from 1000-1200 deg.C in the temperature rise to 1200 deg.C in the middle of cooling through the prescribed holding temperature. The ultra-fine cemented carbide which contains fine tungsten carbide particles, and is high in hardness, resistant in wear, and excellent in toughness can be provided.
|
