A surface coating cutting tool

Abstract

The invention provides a surface coating cutting tool. An average proportion X[avg] of A1 and an average proportion Y[avg] of C of a (Ti[1-X]A1[X])(C[Y]N[1-Y]) layer, of which film formation is realized through chemical evaporation with A1(CH3) as reaction gases on the surface of a substrate, wherein (Xavg and Yavg are both atomic ratios), satisfy 0.60<= X[avg]<=0.95 and 0<= Y[avg]<=0.005. Crystalline grains having cubic crystalline structures exist in crystalline grains forming complex nitrides or a layer of the complex nitrides. In measurement of distribution of degrees of inclination angles of an inclination angle between a normal of surfaces of crystalline grains (111) and the surface of the substrate, a degree ratio in a scope of 0-12 degrees is more than 45% of all the degrees. When a scanning electron microscope is used to observe organizations from the surface sides of the complex nitrides or the layer of the complex nitrides, the crystalline grains having the c cubic crystalline structures have triangular shapes in surfaces perpendicular to a layer thickness direction. A facet formed by an equivalent crystalline plane expressed by (111) of the crystalline grains accounts for an area proportion of more than 35% in the surface perpendicular to the layer thickness direction.

Description

technical field [0001] The present invention relates to a surface-coated cutting tool in which a hard coating exhibits excellent chipping resistance in high-speed interrupted cutting of stainless steel or the like accompanied by high heat generation and an impact load acting on the cutting edge (hereinafter , called the wrapping tool). Background technique [0002] In the past, the following cladding tools are known, which are usually made of tungsten carbide (hereinafter, represented by WC)-based cemented carbide, titanium carbonitride (hereinafter, represented by TiCN)-based cermets or cubic boron nitride (hereinafter represented by TiCN) , represented by cBN) based ultra-high pressure sintered body (hereinafter, these are collectively referred to as the substrate) surface, coated by physical vapor deposition to form a Ti-Al composite nitride layer as a hard coating layer. Such a coated tool is known to exhibit excellent wear resistance, and is used in various application...

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Problems solved by technology

[0015] However, the coated tools described in the above-mentioned Patent Documents 1 and 2 are composed of (Ti 1-X Al X ) The hard coating layer composed of N layer cannot increase the Al content X in the film. Therefore, for example, when it is used for high-speed interrupted cutting of alloy steel, there is a problem of insufficient chipping resistance.

[0016] On the other hand, for (Ti 1-X Al X ) N layer, which can increase the Al content X, and can form a cubic crystal structure, so a hard coating layer with a specified hardness and excellent wear resistance can be obtained, but its adhesion strength with the substrate is insufficient, and its toughness is poor Therefore, when it is used as a clad tool for high-speed intermittent cutting of alloy steel, it is easy to produce abnormal damage such as chipping, chipping, and peeling, and it cannot be said that it can exert satisfactory cutting performance.

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