WC-based cemented carbide

Abstract

This WC-based cemented carbide, which is suitable for a substrate of a surface-coated cutting tool or the like, contains 6.0-10.0 mass% of Co, 0.08-0.90 mass% of Cr (where the ratio Cr content (mass%) / Co content (mass%) is 10% or lower), 0.0-3.8 mass% of M (where M is one or more of V, Ta, Nb, Ti, and Zr), and 4.5-7.5 mass% of C, the balance being W and unavoidable impurities. The WC-based cemented carbide has a binder phase, a hard phase, and a γ phase, the binder phase containing Co as the main component, the hard phase containing a carbide of W as the main component, and the γ phase containing a carbide of M as the main component. In crystal particles constituting the hard phase, the grain diameter C99 (μm) for 99% cumulative particle count is 3.30 or lower, and the ratio C99 / C50 (grain diameter C99 (μm) for 99% cumulative particle count to grain diameter C50 (μm) for 50% cumulative particle count) is 4.80-6.50. The proportion (L) of the phase interface length along which the hard phase and the binder phase are in contact with respect to the total phase interface length of the hard phase is 35% or greater.

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