| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting tool capable of lengthening the tool service life, by surely restraining abrasion and separation of a hard coating layer, even when using carbon steel as a machinable material.SOLUTION: A first compound nitride layer 11 and a second compound nitride layer 12 are alternately formed by four layers or more in total as the hard coating layer 3 on a surface 2a of a tool base body 2 composed of tungsten carbide group hard metal, and the first compound nitride layer 11 is directly formed as a film on the surface 2a of at least the tool base body 2, and has an average layer thickness of 0.5-1.25 μm, and is composed of a compound nitride layer of Al and Ti of the average composition for satisfying 0.3≤X≤0.7(here, an X value is the atomic ratio) when expressed by a composition formula : (AlTi)N, and the second compound nitride layer 12 has an average layer thickness of 0.5-1.25 μm, and is composed of a compound nitride layer of Al and Cr of the average composition for satisfying 0.2≤a≤0.6 (here, an (a) value is the atomic ratio) when expressed by a composition formula : (AlCr)N. |
