SURFACE-COATED CUTTING TOOL

To provide a cutting tool excellent in peeling resistance and chipping resistance even in a cutting work for Ni-based heat-resistant alloy.SOLUTION: There is provided a surface-coated cutting tool comprising a hard coating layer having an average layer thickness of 1.0-20.0 μm. In the high-Ti content phase of a host phase of the hard coating layer, when representing a composition formula by (Ti(1-a)Ala)(CbN(1-b)), the average values aavg and bavg of a and b, respectively are in the following ranges: 0.00≤aavg≤0.30 and 0.000≤bavg≤0.005, and the high-Ti content phase includes 70 area% or more of the crystal grain of NaCl type face-centered cubic structure. In the high-Al content phase of a dispersion phase, when representing a composition formula by (Ti(1-X)AlX)(CYN(1-Y)), the average values Xavg and Yavg of X and Y, respectively are in the following ranges: 0.60≤Xavg≤0.90 and 0.000≤Yavg≤0.005, and the high-Al content phase includes 70 area% or more of the crystal grain of the NaCl type face-centered cubic structure, and disperses in the host phase in a rate of 20-60 area%.SELECTED DRAWING: Figure 1 【課題】Ｎｉ基耐熱合金の切削加工でも、優れた耐剥離性、耐チッピング性を示す切削工具の提供。【解決手段】平均層厚が１．０〜２０．０μｍを有する硬質被覆層を設けた表面被覆切削工具であって、硬質被覆層は、母相のＴｉ高含有相は、組成式：（Ｔｉ（１−ａ）Ａｌａ）（ＣｂＮ（１−ｂ））で表した場合、ａの平均値ａａｖｇと平均値ｂａｖｇが、０．００≦ａａｖｇ≦０．３０、０．０００≦ｂａｖｇ≦０．００５で、ＮａＣｌ型の面心立方構造の結晶粒子を７０面積％以上含み、分散相のＡｌ高含有相は、組成式：（Ｔｉ（１−Ｘ）ＡｌＸ）（ＣＹＮ（１−Ｙ））で表した場合、Ｘの平均値ＸａｖｇとＹの平均値Ｙａｖｇが、０．６０≦Ｘａｖｇ≦０．９０、０．０００≦Ｙａｖｇ≦０．００５で、ＮａＣｌ型の面心立方構造の結晶粒子を７０面積％以上含み、母相中に２０〜６０面積％で分散する、表面被覆切削工具。【選択図】図１