| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface coated high-speed tool steel-made gear cutting tool having a hard coating layer exhibiting excellent wear resistance in high-speed gear cutting of alloy steel. SOLUTION: In this surface coated high-speed tool steel-made gear cutting tool, a hard coating layer is formed on the surface of a high-speed tool steel base by vapor deposition. The hard coating layer is composed of (a) an upper layer and a lower layer, both of which are formed of (Ti, Al, B) N, the upper layer has the average layer thickness ranging from 0.5 to 1.5μm, and the lower layer has the average layer thickness ranging from 2 to 6μm. (b) The upper layer has an alternately stacking structure in which a thin layer A and a thin layer B respectively having the average layer thickness ranging from 5 to 20 nm are stacked. The thin layer A is formed of (Ti, Al, B) N layer satisfying a composition formula: [Ti<SB>1-(E+F)</SB>Al<SB>E</SB>B<SB>F</SB>] N, and the thin layer B is formed of (Ti, Al, B) N layer satisfying a composition formula: [Ti<SB>1-(M+N)</SB>Al<SB>M</SB>B<SB>N</SB>] N. (c) The lower layer has a single phase structure and it is formed of (Ti, Al, B) N layer satisfying a composition formula: [Ti<SB>1-(X+Y)</SB>Al<SB>X</SB>B<SB>Y</SB>] N. COPYRIGHT: (C)2007,JPO&INPIT
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