| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting edge piece having excellent cutting edge chipping resistance, and at the same time, to promote the laborsaving of cutting work. SOLUTION: This cutting tip is composed of brazing on the cutout part of a tip body comprised of this cemented carbide a cutting edge piece comprised of a BN sintered compact having the hardness of 5000 to 6000 kg/mm2 in micro-vickers hardness, or a cutting edge layer composed of the BN compact having the micro-vickers hardness alike, and another cutting edge piece consisting of a grounding layer composed of a cemented carbide, superhigh pressure sintered together therewith. A structure wherein TiN and TiB2 are dispersed and distributed on the grounding of BN ranging from a surface to the specified thin depth within the range of 10 to 50μm, and a reactive thin layer having the micro-vickers hardness of 3500 to 4500 kg/mm2 in surface hardness both are made up on a surface part of a cutting face (top face) comprising a cutting edge ridgeline wherein the cutting face and a rake face in the cutting edge piece are crossed with each other, and on the other hand, the rake face (flank) of the cutting edge piece is composed of holding the hardness of 5000 to 6000 kg/mm2 in the same micro-vickers hardness as the internal hardness of the cutting edge piece.
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