| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface-coated cemented carbide cutting tool that exhibits an appreciable chipping resistance of its hard coating layer in intermittent heavy cutting. SOLUTION: On the surface of a tungsten carbide-based cemented carbide substrate, the surface-coated cemented carbide cutting tool has a hard coating layer formed by a chemical vapor deposition process into a total mean thickness of 5 to 25μm. The hard coating layer comprises: (a) a Ti compound layer containing one or more of TiC, TiN, TiCN, TiCON and TiCNO, having a mean thickness of 0.1 to 5μm and a granular crystal structure, and existing under a residual tensile stress; (b) a TiCN layer containing an upper and a lower partial layer both under a residual tensile stress and having a mean thickness of 2 to 15μm, both which layers have longitudinally growing structures interconnected and which upper layer has a mean thickness accounting for 20 to 40% of the 2-15μm mean thickness; (c) a TiC layer containing an upper and a lower partial layer both under a residual tensile stress and having a mean thickness of 2 to 15μm, both which layers have longitudinally growing structures interconnected and which upper layer has a mean thickness accounting for 20 to 40% of the 2-15μm mean thickness; and (d) an Al2O3 layer having a mean thickness of 0.5 to 10μm and a granular crystal structure and existing under a residual tensile stress.
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