SURFACE COAT CEMENTED CARBIDE MADE CUTTING TOOL WITH HARD COAT LAYER DISPLAYING EXCELLENT CHIPPING RESISTANCE IN HEAVY CUTTING WORK CONDITION

摘要

PROBLEM TO BE SOLVED: To provide a surface coat cemented carbide made cutting tool with a hard coat layer displaying excellent chipping resistance in heavy cutting work condition. SOLUTION: In this surface coat cemented carbide made cutting tool, the hard coat layer comprising composite nitride of Al and Ti is physically deposited on the surface of a tungsten carbide group cemented carbide base body or a carbonitride titanium thermet base body in a total average layer thickness of 1 to 15μm. In the hard coat layer, a point of maximum Al content (a point of minimum Ti content) and a point of minimum Al content (a point of maximum Ti content) alternately and repeatedly exist at a prescribed interval along a layer thickness direction. The hard coat layer has a constituent concentration distribution structure where Al (Ti) content continuously varies from the point of maximum Al content to the point of minimum Al content and vice versa. The point of maximum Al content satisfies a composition formula: (Ti1-XAlX)N (X shows 0.40 to 0.65 in an atomic ratio), the point of minimum Al content satisfies a composition formula: (Ti1-YAlY)N (Y shows 0.05 to 0.35 in an atomic ratio), and the interval between the point of maximum Al content and the point of minimum Al content adjacent each other is 0.01 to 0.1μm. COPYRIGHT: (C)2003,JPO