Patent ID: 6811581
Filing Date: 2004-11-02
Classification: B23F,C21D,C23C,Y10T

Abstract:
A high-speed tool steel gear cutting tool comprising a hard coating which is physical vapor deposited at an overall average thickness of 2 to 15 &mgr;m, is formed on a surface of a base metal of a high-speed tool steel, by alternatingly laminating a plurality of first thin layers and a plurality of second thin layers with respective average thicknesses of 0.005 to 0.2 &mgr;m,each of said first thin layers comprising either or both of a (Ti, Al) N layer and a (Ti, Al) CN layer for which in the case where these are represented by composition formula: [Ti1âˆ’xAlx]N andcomposition formula: [Ti1âˆ’xAlx]C1âˆ’mNmthe atomic ratio based on measurements using an Auger spectroscopy apparatus, of a thickness direction central portion satisfies X: 0.30 to 0.70, m: 0.6 to 0.99, andeach of said second thin layers comprising either or both of a (Ti, Al, Ta) N layer and a (Ti, Al, Ta) CN layer for which in the case where these are represented by composition formula: composition formula: [Ti1âˆ’(X+Y)AlXTaY]N andcomposition formula: [Ti1âˆ’(X+Y)AlXTaY]C1âˆ’mNm, the atomic ratio based on measurements using an Auger spectroscopy apparatus, of a thickness direction central portion satisfies X: 0.30 to 0.70, Y: 0.01 to 0.35 and m: 0.6 to 0.99.