Mitsubishi Materials Corporation

Mitsubishi Materials Kobe Tools Corporation

Akihiro Kondo

Yusuke Tanaka

Kazunori Sato

Eiji Nakamura

Hidemitsu Takaoka

Koichi Maeda

Yasuhiko Tashiro

A cutting tool made of surface-coated cemented carbide having the hard coating layer formed on the surface of a cemented carbide substrate, wherein the hard coating layer has a top layer and a bottom layer, the top layer includes a structure having the thin layer A and the thin layer B being stacked alternately, with the thin layer A having the composition of [TiAlSi]N (A is in a range from 0.01 to 0.06 and B is in a range from 0.25 to 0.35 in an atomic ratio) and the thin layer B having the composition of [TiAlSi]N (C is in a range from 0.30 to 0.45 and D is in a range from 0.10 to 0.15), and the bottom layer comprises single phase structure having the composition of [TiAlSi]N (E is in a range from 0.50 to 0.60 and F is in a range from 0.01 to 0.09).

Cutting tool made of surface-coated cemented carbide with hard coating layer exhibiting excellent wear resistance in high speed cutting operation of high hardness steel

The invention provides a coated cutting tool made of cemented carbide in which a hard coating layer has excellent wear resistance in high-speed cutting operation, wherein (a) a crystal orientation hysteresis layer which consists of a carbonitride compound layer and (b) a hard coating layer which consists of a layer of nitride compound and has a well defined crystal orientation and/or degree of crystallinity are formed on the surface of a cemented carbide substrate, preferably on the surface of a tungsten carbide based cemented carbide or titanium carbonitride based cermet by physical vapor deposition, wherein the crystal orientation hysteresis layer is deposited between the surface of a cemented carbide substrate and the hard coating layer. In one specific example, (a1) the carbonitride compound layer has an average thickness of 0.05 to 0.5 &#x3bc;m and is preferably a Ti&#x2014;Al carbonitride compound layer expressed by the composition formula as (TiAl)(NC), wherein X ranges from 0.05 to 0.20 and Y ranges from 0.01 to 0.15 by atomic ratio and (b1) the nitride compound layer has an average thickness of 2 to 15 &#x3bc;m and is preferably a Ti&#x2014;Al nitride compound layer expressed by the composition formula as (TiAl)N, wherein Z ranges from 0.45 to 0.65 by atomic ratio. In another specific example, (a2) the carbonitride compound layer has an average thickness of 0.05 to 0.5 &#x3bc;m and is preferably a Ti&#x2014;Al carbonitride compound layer expressed by the composition formula as (TiAl)(NC), wherein X ranges from 0.01 to 0.15 and Y ranges from 0.01 to 0.15 by atomic ratio and (b2) the nitride compound layer has an average thickness of 2 to 10 &#x3bc;m and is preferably a Al&#x2014;Ti&#x2014;Si nitride compound layer expressed by the composition formula as (AlTiSi)N, wherein A ranges from 0.35 to 0.55 and B ranges from 0.05 to 0.20 by atomic ratio.

Surface coated cemented carbide cutting tool having hard coating layer exhibiting excellent wear resistance in high speed machining

A surface-coated cutting tool member includes a tungsten carbide based cemented carbide substrate, a titanium carbonitride based cermet substrate, or a cubic boron nitride based sintered substrate; and a hard coating layer of a nitride compound containing aluminum and titanium, formed on a surface of the substrate using a physical vapor deposition method in an overall average thickness of 1 to 15 &#x3bc;m. The hard coating layer has a component concentration profile in which maximum aluminum containing points and minimum aluminum containing points appear alternatingly and repeatedly at a distance from 0.01 to 0.1 &#x3bc;m in a direction of thickness of the hard coating layer. The amount of contained aluminum (or titanium) is changed from the maximum aluminum containing points to the minimum aluminum containing points. The maximum aluminum containing points satisfy a formula: (AlTi)N, wherein X is between 0.70 to 0.95. The minimum aluminum containing points satisfy a formula: (AlTi)N, wherein Y is between 0.40 to 0.65.

Surface-coated cutting tool member having hard coating layer exhibiting superior wear resistance during high speed cutting operation and method for forming hard coating layer on surface of cutting tool

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Kakogawa, Japan

Akihiro Kondo