CUTTING TOOL MADE OF SURFACE COVERING CEMENTED CARBIDE IN WHICH HARD COVERING LAYER EXHIBITS EXCELLENT CHIPPING RESISTANCE AT DEEP CUTTING PROCESSING CONDITION

摘要

PROBLEM TO BE SOLVED: To provide a cutting tool made of surface covering cemented carbide in which a hard covering layer exhibits excellent chipping resistance at a deep cutting processing condition. SOLUTION: The hard covering layer comprising composite nitride of Cr and Al is physically deposited on a surface of a tungsten carbide based cemented carbide substrate or titanium carbide nitride based cermet substrate. The Al maximum containing point and the Al minimum containing point alternately and repeatedly exist at a predetermined space along a layer thickness direction and it has a composition concentration distribution structure in which the Al content continuously varies between both points. The Al maximum containing point satisfies a composition formula: (Cr1-XAlX)N (X represents 0.40-0.60 in an atomic ratio) and the Al minimum containing point satisfies a composition formula: (Cr1-YAlY)N (Y represents 0.05-0.30 in an atomic ratio) respectively. A gap of the adjacent Al maximum containing point and the Al minimum containing point is made to 0.01-0.1μm. COPYRIGHT: (C)2004,JPO