CUTTER FORMED OF SURFACE COVERED CEMENTED CARBIDE WHICH HAS HARD COVER LAYER EXHIBITING EXCELLENT CHIPPING RESISTANCE UNDER HEAVY CUTTING CONDITIONS

摘要

PROBLEM TO BE SOLVED: To provide a cutter formed of surface covered cemented carbide which has a hard cover layer exhibiting excellent chipping resistance under heavy cutting conditions.;SOLUTION: The cutter is formed of the surface covered cemented carbide which consists of a substrate and a hard cover layer. The substrate is made of a tungsten carbide-based hard metal or a titanium carbonitride-based cermet. The hard cover layer is made of a composite nitride containing Al and Zr, and applied to a surface of the substrate so as to have an entire mean thickness of 1 to 15 μm. The hard cover layer has concentration distribution so that Zr maximally contained points and Zr minimally contained points are alternately arranged therein at predetermined intervals in a thickness direction, and that Zr content continuously varies from the Zr maximally contained point to the Zr minimally contained point, or vice versa. The Zr maximally contained point satisfies the following chemical formula: (Ti_1-XZr_X)N, where X represents 0.40 to 0.65 by atomic ratio. The Zr minimally contained point satisfies the following chemical formula: (Ti_1-YZr_Y)N, where Y represents 0.05 to 0.35 by atomic ratio. Further the interval between the adjacent Zr maximally contained point and the Zr minimally contained point ranges from 0.01 to 0.1 μm.;COPYRIGHT: (C)2004,JPO