Surface-coated cutting tool in which hard coating layer exhibits exceptional welding resistance, plastic deformation resistance, and anomalous damage resistance

A surface-coated cutting tool comprising:

• a tool body;
• and
• a hard coating layer formed on a surface of the tool body, wherein
• (a) the hard coating layer includes at least one layer of a TiZr complex carbonitride layer or a TiZrHf complex carbonitride layer having an average layer thickness of 0.5 to 20.0 μm,
• (b) the complex carbonitride layer contains TiZr complex carbonitride or TiZrHf complex carbonitride, and in a case where the complex carbonitride is represented by a composition formula (Ti(1-x)ZrxyHfx(1-y))(N(1-z)Cz),
• the complex carbonitride layer has an average composition in which a content ratio x of a total content of Zr and Hf to a total content of Ti, Zr, and Hf, a content ratio y of a Zr content to the total content of Zr and Hf, and a content ratio z of a C content to a total content of N and C (here, all of x, y, and z are atomic ratios) satisfy 0.10≤x≤0.90, 0<y≤1.0, and 0.08<z<0.60, respectively,
• the complex carbonitride layer contains chlorine in an average chlorine content of 0.001 atom % or more and 0.030 atom % or less,
• (c) the complex carbonitride layer has a composition fluctuation structure in which the content ratio of the total content of Zr and Hf to the total content of Ti, Zr, and Hf and the content ratio of the C content to the total content of N and C change in cycles in at least some crystal grains,
• (c-1) in longitudinal cross section observation, an area ratio of the composition fluctuation structure occupying a structure of the complex carbonitride layer is 10% or more,
• (c-2) regarding the content ratio of the total content of Zr and Hf to the total content of Ti, Zr, and Hf in the composition fluctuation structure, a maximum ZrHf content point showing a maximum content ratio xmax and a minimum ZrHf content point showing a minimum content ratio xmin are repeated, an average distance which is an average value of distances between the repeated maximum ZrHf content point and the minimum ZrHf content point adjacent to each other is 5 to 71 nm, and an average value of absolute values of differences Δx between the maximum content ratio xmax of the maximum ZrHf content point and the minimum content ratio xmin of the minimum ZrHf content point is 0.06 to 0.32,
• (c-3) regarding the content ratio of the C content to the total content of N and C in the composition fluctuation structure, a maximum C content point showing a maximum content ratio zmax and a minimum C content point showing a minimum content ratio zmin are repeated, an average distance which is an average value of distances between the repeated maximum C content point and the minimum C content point adjacent to each other is 5 to 71 nm, and an average value of absolute values of differences Δz between the maximum content ratio zmax of the maximum C content point and the minimum C content ratio zmin is 0.02 or more, and
• (c-4) cycles and positions of the maximum ZrHf content point showing the maximum content ratio xmax and the minimum ZrHf content point showing the minimum content ratio xmin, regarding the content ratio of the total content of Zr and Hf to the total content of the Ti, Zr, and Hf in the composition fluctuation structure, are respectively synchronized with cycles and positions of the maximum C content point showing the maximum content ratio zmax and the minimum C content point showing the minimum content ratio zmin, regarding the content ratio of the C content to the total content of N and C, and an average value of a distance between the maximum ZrHf content point and the maximum C content point at a position closest to the maximum ZrHf content point is ⅕ or less of the average distance between the maximum ZrHf content point and the adjacent minimum ZrHf content point.