| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting tool made of surface-coated cemented carbide, excellent in chipping resistance and exhibiting excellent cutting performance over a long period. SOLUTION: This cutting tool made of surface-coated cemented carbide is obtd. by chemically vapor-depositing and/or physically vapor-depositing, on the surface of a WC base cemented carbide substrate, a hard coating layer having total overage layer thickness of 3 to 20 μm and composed, in order from the surface side of the substrate, of a TiN layer with a granular crystal structure having 0.1 to 2 μm average layer thickness, a TiCN layer with a longitudinally growing crystal structure having 1 to 15 μm average layer thickness, an Al2 O3 layer with a granular crystal structure having 0.5 to 15 μm average layer thickness and also having a crystal structure of the α type, κ type or the mixed type of α and κ and a TiN layre with a granular crystal structure having 0.1 to 3 μm average layer thickness. In this case, on the space between the TiCN layer and the Al2 O3 layer, a Ti2 O3 layer by chemical vapor deposition or physical vapor deposition showing an X-ray diffraction pattern in which the maximum diffraction peak height appears in the angle of diffraction (2θ) of 24.0±1 degrees by X-ray diffraction using CuKα ray as a radiation source is interposed by the average layer thickness of 0.1 to 2 μm.
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