| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface coated cemented carbide cutting tool having hard coating layer exhibiting excellent chipping resistance in high-speed heavy cutting. SOLUTION: In this cutting tool, one layer of the hard coating layer is formed by a hysteresisα-type Al<SB>2</SB>O<SB>3</SB>layer. The hysteresisα-type Al<SB>2</SB>O<SB>3</SB>layer is such that when with a field emission type scanning electron microscope, an electron beam is applied to the individual crystal grains having hexagonal crystal lattice existing in a measurement range of the surface polishing side, an inclination angle made by a normal of (0001) face, which is a crystal plane of the crystal grain, is measured, the measured inclination angles are sectioned, and the frequencies of existing in the respective sections are added up, the layer shows an inclination angle frequency distribution graph in which the peak exists at least in an inclination angle section within the range of 7 to 15 degrees, and an inclination angle section within the range of 0 to 7 degrees, and at the percentage of occupying the whole frequencies, the total of frequencies existing in the range of 7 to 15 degrees is 35 to 50%, and the total of frequencies existing in the range of 0 to 7 degrees is 25 to 40%. Further, a hard coating layer residual stress reducing pattern is formed. COPYRIGHT: (C)2007,JPO&INPIT
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