SURFACE-COATED CUTTING TOOL HAVING HARD COATING LAYER EXERTING EXCELLENT ABRASION RESISTANCE IN HIGH-SPEED CUTTING OF HIGH-HARDNESS STEEL

摘要

PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool having a hard coating layer exerting superior abrasion resistance in high-speed cutting of high-hardness steel.;SOLUTION: The surface-coated cutting tool is composed by forming the hard coating layer on the surface of a cemented carbide base body or on the surface of a high-speed tool steel base body by vapor deposition. The hard coating layer (a) is composed of an upper layer and a lower layer both of which are composed of (Cr, Al, Si)N. The upper layer has an average layer thickness of 0.5-1.5 μm and the lower layer has an average layer thickness of 2-6 μm. The upper layer (b) has an alternate lamination structure of a thin layer (A) and thin layer (B) both of which respectively have an average layer thickness of 5-20 nm (nanometer) for each one-layer. The thin layers (A, B) are respectively composed of a (Cr, Al, Si)N layer satisfying a specific composition formula. The lower layer (c) has a single-phase structure and is composed of a (Cr, Al, Si)N layer satisfying a composition formula: [Cr_1-(X+Z)Al_XSi_Z]N (where, X shows 0.45-0.65 and Z shows 0.01-0.10 by atom ratio).;COPYRIGHT: (C)2007,JPO&INPIT