Ultra-fine cemented carbide, and cutting tool and wear-resistant tool using the same

Abstract

Provided is an ultra-fine cemented carbide that has high hardness and exhibits excellent transverse-rupture-strength. The ultra-fine cemented carbide includes a hard phase, containing tungsten carbide (WC) as a main component, in an amount of 80 wt % or more and 99.4 wt % or less, a carbonitride phase, containing titanium carbonitride (Ti(C,N)) as a main component produced by carbonitriding of a titanium (Ti) oxide during sintering, in an amount of 0.1 wt % or more and 10.0 wt % or less, and a binder phase, containing at least one selected from cobalt (Co), nickel (Ni), or iron (Fe) as a main component, in an amount of 0.50 wt % or more and 20 wt % or less, and the binder phase contains chromium carbide (Cr3C2) in an amount of 0.10 wt % or more and 20.0 wt % or less based on all of the binder phase, and in the ultra-fine cemented carbide, the hard phase, the carbonitride phase, and the binder phase total 100 wt %, WC after the sintering has an average grain size of 1.0 μm or less, the nitrogen content is 0.10 wt % or more and 1.25 wt % or less, and the carbon content is 4.80 wt % or more and 6.30 wt % or less.

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