| 摘要 |
PROBLEM TO BE SOLVED: To provide a hard metal having high transverse strength with little variation, and to provide such a rotating tool with the use of the hard metal as to have excellent breakage resistance when used for small diameter drilling or high-feed cutting. SOLUTION: The hard metal 1 has a structure, when observed with a transmission electron microscope, having tungsten carbide particles 2 with an average particle diameter of 0.1 to 0.4μm, a binding phase 3 which is made mainly of 3-13 mass% cobalt and combines tungsten carbide particles 2, and tungsten carbide particles 4 with particle diameters of 0.05μm or smaller, of which the number is 10% or less with respect to the total number of the tungsten carbide particles 2; has a coercive force of 34,000 to 56,000 A/m, and a saturation magnetization rate of 1.35 to 1.65μTm<SP>3</SP>in terms of 1 mass% of cobalt; and when a filtrate is prepared by pulverizing the hard metal, dissolving a pulverized powder having passed through a screen of #20 mesh in a dilute hydrochloric acid (HCl:H<SB>2</SB>O = 1:1) of 50°C for 24 hours, and filtering the solution, contains tungsten in an amount of 8 to 24 mass% with respect to the total metal contents in the filtrate. COPYRIGHT: (C)2005,JPO&NCIPI
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