| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface coated cutting tool in which a hard coating layer exhibits superior cutting performance in cutting machining of high hardness steel such as quenched steel.SOLUTION: A surface coated cutting tool is obtained by forming a hard coating layer comprising a lower layer and an upper layer on a surface of a tool base body comprising WC-based cemented carbide or TiCN-based cermet. In the tool, (a) the lower layer comprises a layer having an average layer thickness of 0.1-2.0 μm and comprising boride, nitride, and oxide of either one kind of Zr or Ti, (b) in the lower layer, the oxide of either one kind of Zr or Ti occupies 5-90 area% of the section of the lower layer, and (c) the upper layer comprises cubic boron nitride having an average layer thickness of 0.1-10 μm, wherein the upper layer has a columnar crystal structure having an average minor axis of crystal grains of 10-300 nm, a half-value width of a (111) peak is equal to or less than 1.5° when measured by thin film X-ray diffraction using a Cu tube at an incident angle of 0.5°, and nanoindentation hardness is 50-75 GPa. |
