SURFACE-COVERED CEMENTED CARBIDE MADE CUTTING TOOL HAVING HARD COATING LAYER TO EXHIBIT EXCELLENT CHIPPING RESISTANCE IN HIGH-SPEED HEAVY CUTTING CONDITION

摘要

PROBLEM TO BE SOLVED: To provide a surface-covered cemented carbide made cutting tool having a hard coating layer to exhibit excellent chipping resistance in a high- speed heavy cutting condition. SOLUTION: The hard coating layer of 1-15μm made of a complex nitride layer composed of Al, Ti and Cr is formed on the surface of a WC-based cemented carbide substrate or carbonitride titanium-based cermet substrate in the layer thickness direction. This hard coating layer has a component concentration distribution structure arranged to have an Al component maximum content point (hereinafter A) and an Al component minimum content point (hereinafter B) alternately repeatedly in predetermined spaces and designed to have an Al component content which varies continuously from the point A to the point B and the point B to the point A. The point A satisfies a composition formula: (Ti1-(X+Z)AlXCrZ)N (wherein X is 0.45-0.65 and Z is 0.01-0.15 in atomic ratio). The point B satisfies a composition formula: (Ti1-(X+Z)AlXCrZ)N (wherein X is 0.15-0.40 and Z is 0.01-0.15 in atomic ratio). The space between the point A and the point B is 0.01-0.1μm. COPYRIGHT: (C)2004,JPO