| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting tool made of composite cermet, excellent in breakage resistance and showing superior machinability over a long period. SOLUTION: This cutting tool made of composite cermet is constituted of a composite cermet having a structure which consists, microscopically, of spotted phases and continuous phases of skeleton structure existing between the spotted phases and in which the size of the spotted phases, measured by the longest diameter, is <=200μm and the spotted phases with a size of 40-200μm comprise 10-50 area % of the whole, the total amount with the continuous phases. Further, the spotted phases are constituted of a cemented carbide having a composition consisting of 5-20 wt.% of Co and/or Ni as binding-phase-forming component and the balance essentially tungsten carbide as dispersed-phase-forming component. Moreover, the continuous phases are constituted of a titanium carbonitride type cermet having a composition consisting of 5-20 wt.% of Co and/or Ni as binding-phase-forming component and the balance essentially a Ti-type compound carbonitride solid solution, as dispersed-phase-forming component, of Ti and one or more elements among Nb, Ta, W, Mo, Zr, V, Cr, and Hf.
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