JP7119264B2 - A surface-coated cutting tool with a hard coating layer that exhibits excellent chipping resistance and wear resistance. - Google Patents

Description

The present invention is used in high-speed intermittent cutting of carbon steel, alloy steel, cast iron, etc., which generates high heat and applies an impact load to the cutting edge, and the hard coating layer has excellent chipping resistance. , a surface-coated cutting tool (hereinafter referred to as a coated tool) that exhibits excellent wear resistance over a long period of use.

Conventionally, in general, tungsten carbide (hereinafter referred to as WC) based cemented carbide, titanium carbonitride (hereinafter referred to as TiCN) based cermet or cubic boron nitride (hereinafter referred to as cBN) based ultra high pressure sintered body A coated tool in which a Cr--Al-based or Ti--Al-based composite nitride layer is formed as a hard coating layer by physical vapor deposition on the surface of the tool base (hereinafter collectively referred to as the tool base). These are known to exhibit excellent wear resistance.
However, although the conventional coated tools coated with a Cr-Al-based or Ti-Al-based composite nitride layer are relatively excellent in wear resistance, they may cause abnormalities such as chipping when used under high-speed interrupted cutting conditions. Various proposals have been made to improve the hard coating layer because it is prone to wear.

For example, in Patent Document 1, in order to improve chipping resistance and wear resistance in high-speed interrupted cutting of stainless steel, Ti alloy, etc., a hard coating consisting of a lower layer, an intermediate layer and an upper layer is applied to the surface of the tool substrate. A layer is provided, the lower layer has a predetermined average layer thickness, and is a Ti _1-X Al _X N layer, a Ti _1-X Al _X C layer, a Ti _1-X Al _X CN layer (X is Al The content ratio (atomic ratio) of 0.65 ≤ X ≤ 0.95) is composed of a TiAl compound having a cubic crystal structure consisting of one or more layers, and the intermediate layer has a predetermined average layer thickness and a Cr _1-Y Al _Y N layer, a Cr _1-Y Al _Y C layer, and a Cr _1-Y Al _Y CN layer (Y is the Al content ratio (atomic ratio), and 0.60 ≤ Y ≤ 0.90) _, the _lower layer and the It has been proposed to improve the adhesion strength of the top layer, thereby improving chipping and abrasion resistance.

In addition, Patent Document 2 discloses that a lower layer, an intermediate layer and an upper layer are applied to the surface of a tool substrate in order to improve chipping resistance and wear resistance in high-speed interrupted cutting of heat-resistant alloys such as precipitation hardened stainless steel and Inconel. The lower layer is a Ti _1-X Al _X N layer, a Ti _1-X Al _X C layer, a Ti _1-X Al _X CN layer (X is Al is composed of a Ti compound having a cubic crystal structure consisting of one or more layers of 0.65 ≤ X ≤ 0.95), and the intermediate layer is a predetermined average layer A thick Cr _1-Y Al _Y N layer, a Cr _1-Y Al _Y C layer, and a Cr _1-Y Al _Y CN layer (Y indicates the content of Al, and the atomic ratio is 0.60≦Y≦0.60). 90), composed of a Cr compound having a cubic crystal structure consisting of one or more layers, and the upper layer is Al ₂ O ₃ having micropores with a predetermined pore diameter and pore density and an average layer thickness By configuring with, the adhesion strength between the lower layer and the upper layer is improved, and by making the upper layer an Al ₂ O ₃ layer having micropores with a predetermined pore diameter and pore density, mechanical and thermal It has been proposed to reduce the impact and thereby improve chipping resistance and wear resistance.

Furthermore, Patent Document 3 discloses that (Al _1-X Cr _X ) N (where X is the atomic ratio, and X=0.3 to 0.6) layer is provided, and the normal line of the {100} plane is provided with respect to the normal line of the polished surface of the tool substrate. In the inclination angle number distribution graph created by measuring the inclination angle formed by, the highest peak exists in the inclination angle section of 30 to 40 degrees, the total frequency is 60% or more of the whole, and the surface polished surface In the constituent atom sharing lattice point distribution graph created by measuring the tilt angle formed by the normal of the {112} plane with respect to the normal of The high-temperature strength of the (Al _1-X Cr _X )N layer is improved by forming the crystal orientation and the lattice point distribution morphology shared by the constituent atoms, thereby improving the chipping resistance of the hard coating layer in heavy cutting. It is proposed to improve

Further, Patent Document 4 discloses a surface-coated cutting tool comprising a tool substrate and a hard coating layer formed on the substrate, wherein the hard coating layer contains either one or both of Al and Cr. , at least one element selected from the group consisting of Groups 4a, 5a, and 6a of the periodic table and Si, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron. and chlorine, the wear resistance and oxidation resistance of the hard coating layer are dramatically improved.

Further, for example, in Patent Document 5, chemical vapor deposition is performed in a mixed reaction gas of TiCl ₄ , AlCl ₃ and NH ₃ in a temperature range of 650 to 900° C. to reduce the Al content ratio x to 0.00. 65-0.95 (Ti _1-x Al _x )N layer can be deposited, but this document also mentions Al ₂ O on top of this (Ti _1-x Al _x )N layer. By forming a (Ti _1-x Al _x )N layer with a _three -layer coating and thereby increasing the thermal insulation effect, with the value of x increased from 0.65 to 0.95, There is no disclosure as to what effect it has on cutting performance.

Further, in Patent Document 6, a TiCN layer and an Al ₂ O ₃ layer are used as inner layers, and a (Ti _1-x Al _x )N layer (where x is 0.65 to 0.9) is coated as an outer layer, and a compressive stress of 100 to 1100 MPa is applied to the outer layer to improve the heat resistance and fatigue strength of the coated tool. It is proposed to

JP 2014-208394 A JP 2014-198362 A JP 2009-56539 A Japanese Patent Application Laid-Open No. 2006-82207 Japanese translation of PCT publication No. 2011-516722 Japanese Patent Publication No. 2011-513594

In recent years, there has been a strong demand for labor saving and energy saving in cutting. Abnormal damage resistance such as peeling resistance is required, and excellent wear resistance over long-term use is also required.
However, in the coated tools described in Patent Documents 1 and 2, the adhesion strength between the lower layer and the upper layer is improved by interposing a CrAl compound and a Cr compound as an intermediate layer of the hard coating layer, thereby improving the durability. Despite efforts to improve chipping resistance, the strength and hardness of the CrAl compound and Cr compound themselves are not sufficient. I can't say
In addition, in the coated tool described in Patent Document 3, the Cr content ratio of the hard coating layer made of (Al _1-X Cr _X )N is adjusted, and the crystal orientation and the constituent atom shared lattice point distribution By controlling the morphology, the strength of the hard coating layer can be improved, and as a result, the chipping resistance and fracture resistance can be improved, but the strength and strength of the (Al _1-X Cr _X )N layer Since the hardness is not sufficient, excellent chipping resistance and wear resistance cannot be exhibited over a long period of use, and there is a problem that the tool life is short in high-speed interrupted cutting of alloy steel.
In addition, the coated tool described in Patent Document 4 is intended to improve wear resistance and oxidation resistance, but under cutting conditions that involve impact such as high-speed interrupted cutting, chipping resistance There was a problem that the sex was not enough.
In addition, in the (Ti _1-x Al _x )N layer formed by chemical vapor deposition described in Patent Document 5, the content x of Al can be increased and a cubic crystal structure can be formed. Therefore, although a hard coating layer having a predetermined hardness and excellent wear resistance can be obtained, there is a problem that the toughness is inferior.
Furthermore, although the coated tool described in Patent Document 6 has a predetermined hardness and is excellent in wear resistance, it is inferior in toughness. However, there is a problem that abnormal damage such as chipping, chipping, and peeling is likely to occur, and satisfactory cutting performance cannot be said to be exhibited.
Therefore, in high-speed interrupted cutting of carbon steel, alloy steel, cast iron, etc. with high heat generation and impact load acting on the cutting edge, the hard coating layer has excellent chipping resistance and excellent wear resistance. There is a demand for a coated tool that combines

Therefore, from the above viewpoint, the present inventors have found that at least a composite nitride or composite carbonitride of Cr and Al (hereinafter referred to as "(Cr, Al) (C, N)" or "(Cr _1-x Al _x ) (C _y N _1-y )”), and a composite nitride or composite carbonitride of at least Ti and Al (hereinafter referred to as Chipping resistance of a coated tool provided with a hard coating layer containing "(Ti, Al) (C, N)" or "(Ti _1-α Al _α ) (C _γ N _1-γ )") As a result of intensive research aimed at improving the durability and wear resistance, the following findings were obtained.

That is, it includes at least one conventional (Cr _1-x Al _x ) (C _y N _1-y ) layer or (Ti _1-α Al _α )(C _γ N _1-γ ) layer, and a predetermined The hard coating layer having an average layer thickness of (Cr _1-x Al _x ) (C _y N _1-y ) layer or (Ti _1-α Al _α ) (C _γ N _1-γ ) layer is the tool When it is formed in a columnar shape perpendicular to the substrate, it has high abrasion resistance. On the other hand, the higher the anisotropy of the (Cr _1-x Al _x ) (C _y N _1-y ) layer or the (Ti _1-α Al _α ) (C _γ N _1-γ ) layer, the higher the (Cr _{1 -x} Al _x ) (C _y N _1-y ) layer or (Ti _1-α Al _α ) (C _γ N _1-γ ) layer is reduced in toughness, resulting in chipping resistance and fracture resistance. However, it cannot be said that sufficient wear resistance can be exhibited over a long period of use, and that the tool life is also unsatisfactory.
Therefore, the present inventors have investigated (Cr _1-x Al _x ) (C _y N _1-y ) layers and (Ti _1-α Al _α ) (C _γ N _1-γ ) layers that constitute the hard coating layer. As _a result of _{intensive research} on the _layers , _{Si , Zr} , _B , V, and Cr (hereinafter referred to as “Me”) containing (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) layer is NaCl type It contains crystal grains having a face-centered cubic structure (hereinafter sometimes simply referred to as “cubic crystal structure”), and the average orientation difference within the crystal grains of the crystal grains having the cubic crystal structure is 2 degrees or more. With a new idea, we succeeded in increasing both hardness and toughness by inducing strain in grains having a cubic crystal structure, and as a result, (Cr _1-x Al _x )(C _y N _1-y ) As for the layer, we found a new finding that it is possible to improve the wear resistance as well as the _{chipping resistance} of the _{hard coating layer} . As for the layer, the inventors have found new knowledge that the chipping resistance and fracture resistance of the hard coating layer can be improved.

In particular,
(1) The hard coating layer is configured to include at least a composite nitride or composite carbonitride layer of Cr and Al, and the layer has a composition formula: (Cr _1-x Al _x ) (C _y N _{1- y} ), in particular, the average content ratio x _avg of Al in the total amount of Cr and Al and the average content ratio y _avg of C in the total amount of C and N (where x _avg and y _avg are either atomic ratio) satisfy 0.70 ≤ x _avg ≤ 0.95 and 0 ≤ y _avg ≤ 0.005, respectively, and have a cubic crystal structure in the crystal grains constituting the composite nitride or composite carbonitride layer When the crystal orientation of the crystal grain is analyzed from the longitudinal cross-sectional direction using an electron beam backscatter diffraction device and the average orientation difference within the crystal grain is obtained, the average orientation within the crystal grain Crystal grains exhibiting a difference of 2 degrees or more are present in an area ratio of 40% or more of the composite nitride or composite carbonitride layer, so that the crystal grains having a cubic crystal structure are distorted, and the conventional hard coating layer In comparison, the hardness and toughness of the (Cr _1-x Al _x )(C _y N _1-y ) layer are increased, resulting in improved wear resistance as well as chipping resistance.
(2) The hard coating layer includes at least a composite nitride or composite carbonitride layer of Ti, Al, and Me (where Me is one element selected from Si, Zr, B, V, and Cr). , the composition formula: (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ), in particular, the average content ratio of Al to the total amount of Ti, Al and Me α _avg and Me The average content ratio β _avg of C in the total amount of Ti, Al and Me and the average content ratio γ _avg of C in the total amount of C and N (where α _avg , β _avg , and γ _avg are all atomic ratios) , respectively, satisfying 0.60≦α _avg , 0.005≦β _avg ≦0.10, 0≦γ _avg ≦0.005, 0.605≦α _avg +β _avg ≦0.95, and a composite nitride or Some crystal grains constituting the composite carbonitride layer have a cubic crystal structure, and the crystal orientation of the crystal grains is analyzed from the longitudinal cross-sectional direction using an electron beam backscattering diffraction device, and the crystals of the individual crystal grains. When the average orientation difference within the grain is determined, the crystal grains exhibiting the average orientation difference within the grain of 2 degrees or more are present in an area ratio of the composite nitride or composite carbonitride layer of 40% or more. _{The grains having the _} It has been found that chipping resistance and fracture resistance are improved, and excellent wear resistance is exhibited over a long period of time.

Then, the (Cr _1-x Al _x ) (C _y N _1-y ) layer and the (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) layer having the above configuration are For example, the film can be formed by the following chemical vapor deposition method in which the reaction gas composition is periodically changed on the tool substrate surface.

(1) For the (Cr _1-x Al _x )(C _y N _1-y ) layer The chemical vapor deposition reactor used contains gas group A consisting of NH ₃ and H ₂ and CrCl ₃ , AlCl ₃ , Al(CH ₃ ) A gas group B consisting of ₃ , N ₂ and H ₂ is supplied into the reactor from separate gas supply pipes, and the supply of gas group A and gas group B into the reactor is, for example, at a constant cycle The gas is supplied so as to flow for a period of time shorter than the cycle, and the gas supply of the gas group A and the gas group B is caused to have a phase difference shorter than the gas supply time. The composition of the reaction gas on the surface can be temporally changed to (a) gas group A, (b) a mixed gas of gas group A and gas group B, and (c) gas group B. By the way, in the present invention, there is no need to introduce a long-time evacuation process intended for strict gas replacement. Therefore, as a gas supply method, for example, by rotating the gas supply port, rotating the tool base, or reciprocating the tool base, the reaction gas composition on the surface of the tool base is changed to (a) gas group A (b) a mixed gas of gas group A and gas group B; (c) a mixed gas mainly of gas group B;
On the surface of the tool substrate, the reaction gas composition (% by volume of the total gas group A and gas group B) is added, for example, gas group A is NH ₃ : 2.0 to 3.0%, H ₂ : 65 to 75. %, gas group B: AlCl ₃ : 0.6 to 0.9%, CrCl ₃ : 0.2 to 0.3%, Al(CH ₃ ) ₃ : 0 to 0.5%, N ₂ : 12.5 ~15.0%, H ₂ : balance, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 750 to 900 ° C., supply cycle 1 to 5 seconds, gas supply time per cycle 0.15 to By performing the thermal CVD method for a predetermined time with a phase difference of 0.25 seconds between the supply of gas group A and gas group B of 0.10 to 0.20 seconds, a predetermined target layer thickness of (Cr _1-x Al _x ) Deposit a (C _y N _1-y ) layer.

As described above, gas group A and gas group B are supplied so that there is a difference in the time it takes to reach the surface of the tool substrate. High-speed cutting of alloy steels, etc., where a local distortion of the crystal lattice is formed, as a result of which the hardness is improved, and as a result, the wear resistance is improved, and the cutting edge is subjected to intermittent and impact loads. It was found that the hard coating layer can exhibit excellent cutting performance over a long period of use even when subjected to cutting.

(2) (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) layer The chemical vapor deposition reactor used contains gas group A consisting of NH ₃ and H ₂ , TiCl ₄ , Al ( Gas group B consisting of CH ₃ ) ₃ , AlCl ₃ , MeCl _n (Me chloride), N ₂ , and H ₂ is supplied into the reactor from separate gas supply pipes, and gas group A and gas group B The gas is supplied into the reactor, for example, at a time interval of a certain cycle, and the gas is supplied so as to flow for a time period shorter than the cycle. The composition of the reaction gas on the surface of the tool substrate is divided into gas group A (first reaction gas), mixed gas of gas group A and gas group B (second reaction gas), gas group B (the third reaction gas) can be changed over time. By the way, in the present invention, there is no need to introduce a long-time evacuation process intended for strict gas replacement. Therefore, as a gas supply method, for example, by rotating the gas supply port, rotating the tool base, or reciprocating the tool base, the reaction gas composition on the surface of the tool base is changed mainly to gas group A. mixed gas (first reaction gas), mixed gas of gas group A and gas group B (second reaction gas), and mixed gas mainly composed of gas group B (third reaction gas). Realization is possible.
On the surface of the tool substrate, the reaction gas composition (% by volume of the total gas group A and gas group B) is added, for example, gas group A is NH ₃ : 2.0 to 3.0%, H ₂ : 65 to 75. %, AlCl ₃ as gas group B: 0.6 to 0.9%, TiCl ₄ : 0.2 to 0.3%, MeCl _n (chloride of Me): 0.1 to 0.2%, Al ( CH ₃ ) ₃ : 0 to 0.5%, N ₂ : 12.5 to 15.0%, H ₂ : balance, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 700 to 900°C, Thermal CVD is performed for a predetermined time with a supply cycle of 1 to 5 seconds, a gas supply time of 0.15 to 0.25 seconds per cycle, and a phase difference between the gas group A and the gas group B of 0.10 to 0.20 seconds. A (Ti _1-α-β Al _α Me _β )(C _γ N _1-γ ) layer having a predetermined target layer thickness is formed by performing the method.

As described above, gas group A and gas group B are supplied so that there is a difference in the time it takes to reach the surface of the tool substrate. It has been found that a local distortion of the crystal lattice is formed, resulting in a dramatic improvement in toughness. As a result, the fracture resistance and chipping resistance are particularly improved, and even when used for high-speed interrupted cutting of alloy steel, etc., where intermittent and impact loads are applied to the cutting edge, the hard coating layer can be used for a long time. It has been found that excellent cutting performance can be exhibited over use.

The present invention was made based on the above findings,
"(1) A surface coating in which a hard coating layer is formed on the surface of a tool substrate made of any one of a tungsten carbide-based cemented carbide, a titanium carbonitride-based cermet, and a cubic boron nitride-based ultra-high pressure sintered body. In cutting tools,
(a) the hard coating layer is a composite nitride of Ti , Al, and Me (where Me is one element selected from Si, Zr, B, V, and Cr) having an average layer thickness of 1 to 20 μm; or including at least a composite carbonitride layer,
its composition,
When represented by the composition formula: (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ), the proportion of Al in the composite nitride or composite carbonitride layer to the total amount of Ti, Al, and Me The average content ratio α _avg , the average content ratio β _avg of Me in the total amount of Ti, Al, and Me, and the average content ratio γ _avg of C in the total amount of C and N (where α _avg , β _avg , γ _avg are atomic ratios) are respectively 0.60 ≤ α _avg , 0.005 ≤ β _avg ≤ 0.10, 0 ≤ γ _avg ≤ 0.005, 0.605 ≤ α _avg + β _avg ≤ 0.95 satisfied,
(b) the composite nitride or composite carbonitride layer includes at least a composite nitride or composite carbonitride phase having a NaCl-type face-centered cubic structure;
(c) The crystal orientation of the crystal grains of the composite nitride or composite carbonitride having a NaCl-type face-centered cubic structure among the crystal grains constituting the composite nitride or composite carbonitride layer is determined by electron beam backscattering. When the average misorientation in each crystal grain is obtained by analyzing from the longitudinal cross-sectional direction using a diffractometer, the crystal grains exhibiting the average misorientation in the crystal grain of 2 degrees or more are composite nitrides or composite carbons. A surface-coated cutting tool, wherein the nitride layer is present in an area ratio of 40% or more of the total area.
(2) The composite nitride or composite carbonitride layer is composed of a single phase of a composite nitride or composite carbonitride of Ti, Al, and Me having a NaCl-type face-centered cubic structure (1 ), the surface-coated cutting tool described in .
(3) The composite nitride or composite carbonitride layer contains at least 70 area % or more of a composite nitride or composite carbonitride phase of Ti, Al, and Me having a NaCl-type face-centered cubic structure. The surface-coated cutting tool according to (1) or (2).
(4) Between the tool substrate and the composite nitride or composite carbonitride layer, one layer of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride layer, or A surface-coated cutting tool according to any one of (1) to (3), characterized in that there is a lower layer consisting of two or more Ti compound layers and having a total average layer thickness of 0.1 to 20 μm.
(5) An upper layer containing at least an aluminum oxide layer is formed on the composite nitride or composite carbonitride layer with a total average layer thickness of 1 to 25 μm (1) to (4) ) The surface-coated cutting tool according to any one of ).
(6) Any one of (1) to (5), wherein the composite nitride or composite carbonitride layer is formed by a chemical vapor deposition method containing at least trimethylaluminum as a reactive gas component. A method for manufacturing a surface-coated cutting tool. ”
It is characterized by
The term "average orientation difference within crystal grains" means a GOS (Grain Orientation Spread) value, which will be described later.

In the surface-coated cutting tool, which is an embodiment of the reference coated tool of the present invention (hereinafter also referred to as "the reference coated tool of the present invention") , the surface-coated cutting tool in which a hard coating layer is provided on the surface of the tool substrate, The coating layer includes at least a composite nitride or composite carbonitride layer of Cr and Al with an average layer thickness of 1 to 20 μm, and is represented by the composition formula: (Cr _1-x Al _x ) (C _y N _1-y ) In particular, the average content ratio x _avg of Al in the total amount of Cr and Al and the average content ratio y _avg of C in the total amount of C and N (where x _avg and y _avg are both atomic ratios) are , respectively satisfying 0.70 ≤ x _avg ≤ 0.95 and 0 ≤ y _avg ≤ 0.005, and a NaCl type face-centered cubic structure in the crystal grains constituting the composite nitride or composite carbonitride layer When the crystal orientation of the crystal grain is analyzed from the longitudinal cross-sectional direction using an electron beam backscatter diffraction device to obtain the average orientation difference in the crystal grain of each crystal grain, the average orientation in the crystal grain When crystal grains exhibiting a difference of 2 degrees or more exist in an area ratio of 40% or more with respect to the entire composite nitride or composite carbonitride layer, strain occurs in the crystal grains having a cubic crystal structure. As a result, the effect of improving wear resistance without impairing chipping resistance is exhibited, and compared to conventional hard coating layers, excellent cutting performance over long periods of use is exhibited, and the long life of the coated tool is achieved.
Further, a surface-coated cutting tool (hereinafter also referred to as " coated tool of the present invention" or "cutting tool of the present invention" ), which is an embodiment (mode) of the present invention, in which a hard coating layer is provided on the surface of the tool substrate. , the hard coating layer includes at least a composite nitride or composite carbonitride layer of Ti, Al, and Me with an average layer thickness of 1 to 20 μm, and has a composition formula: (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ), in particular, the average content ratio α _avg of Al to the total amount of Ti, Al, and Me in the composite nitride or composite carbonitride layer and the total amount of Ti, Al, and Me of Me The average content ratio β _avg in the amount and the average content ratio γ _avg of C in the total amount of C and N (where α _avg , β _avg , and γ _avg are all atomic ratios) are each 0.60 ≤ α _avg , 0.005 ≤ β _avg ≤ 0.10, 0 ≤ γ _avg ≤ 0.005, 0.605 ≤ α _avg + β _avg ≤ 0.95, and constitutes a composite nitride or composite carbonitride layer Some crystal grains have a cubic crystal structure, and the crystal orientation of the crystal grains was analyzed from the longitudinal cross-sectional direction using an electron beam backscattering diffraction device to obtain the average orientation difference within each crystal grain. In this case, crystal grains exhibiting an average misorientation in the crystal grains of 2 degrees or more are present in an area ratio of 40% or more of the entire composite nitride or composite carbonitride layer, so that the crystal grains having a cubic crystal structure Due to the strain, the hardness and toughness of the grains are improved. As a result, the chipping resistance is improved without impairing the wear resistance. Longevity is achieved.

A composite nitride or composite carbonitride layer of Cr and Al as an embodiment (aspect) of the reference coated tool of the present invention, or a composite nitride or composite carbonitride layer of Ti, Al and Me of the coated tool of the present invention 1 is a schematic illustration of a method for measuring the average misorientation in crystal grains of crystal grains having an NaCl-type face-centered cubic structure (cubic crystal). A composite nitride or composite carbonitride layer of Cr and Al that constitutes the hard coating layer of the embodiment (aspect) of the reference coated tool of the present invention, or a layer of Ti, Al, and Me as an aspect of the coated tool of the present invention FIG. 2 is a schematic diagram of a film configuration, schematically showing a cross section of a composite nitride or composite carbonitride layer. In the cross section of the composite nitride or composite carbonitride layer of Cr and Al that constitutes the hard coating layer as an embodiment (aspect) of the reference coated tool of the present invention, it has a NaCl type face-centered cubic structure (cubic crystal) An example of a histogram showing the area ratio of the grain intra-grain mean misorientation (GOS) of individual grains is shown. The vertical dotted line in the histogram indicates the boundary line where the average orientation difference within the crystal grain is 2°, and the bar on the right side of the vertical dotted line in the figure indicates the average orientation difference within the crystal grain of 2° or more. of the The same applies to FIGS . 4 to 6 below. NaCl-type face-centered cubic structure (cubic crystal) in the cross section of the composite nitride or composite carbonitride layer of Cr and Al constituting the hard coating layer of the reference comparative coated tool, which is a comparative example of the reference coated tool of the present invention. 1 shows an example of a histogram showing the area ratio of grain average misorientation (GOS) of individual grains having . In the cross section of the composite nitride or composite carbonitride layer of Ti, Al and Me that constitutes the hard coating layer of the coated tool of the present invention, which corresponds to an embodiment of the present invention, a NaCl type face-centered cubic structure (cubic crystal) is formed. 1 shows an example of a histogram showing the area ratio of the average misorientation (GOS value) in crystal grains of individual crystal grains. In the cross section of the composite nitride or composite carbonitride layer of Ti, Al and Me that constitutes the hard coating layer of the comparative coated tool, which is a comparative example of the coated tool of the present invention , a NaCl type face-centered cubic structure (cubic crystal) is formed. 1 shows an example of a histogram showing the area ratio of the average orientation difference (GOS value) within crystal grains of individual crystal grains.

Hereinafter, the reference coated tool of the present invention, which is a reference embodiment of the present invention, and the coated tool of the present invention, which is an embodiment of the present invention, will be described in detail.

Average layer thickness of the composite nitride or composite carbonitride layer constituting the hard coating layer:
The hard coating layer, which is a reference embodiment of the present invention, is a composite nitride or composite of Cr and Al represented by the chemical vapor deposition composition formula: (Cr _1-x Al _x ) (C _y N _1-y ) The hard coating layer, which includes at least a carbonitride layer and is an embodiment of the present invention, is chemically vapor-deposited with the composition formula: (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) contains at least a composite nitride or composite carbonitride layer of Ti, Al and Me represented by These composite nitride or composite carbonitride layers have high high-temperature hardness and excellent wear resistance, and the effect is conspicuous especially when the average layer thickness is 1 to 20 μm. The reason for this is that if the average layer thickness is less than 1 μm, the layer thickness is too thin to ensure sufficient wear resistance over long-term use, while if the average layer thickness exceeds 20 μm, the This is because the crystal grains of the composite nitride or composite carbonitride layer tend to coarsen, and chipping tends to occur.
Therefore, the average layer thickness was set to 1 to 20 μm.

Composition of the composite nitride or composite carbonitride layer constituting the hard coating layer:
( ₁ ) Composite nitride or composite _carbonitride layer of _Cr and _Al , which is a reference embodiment of the present invention. The average content ratio x _avg of C in the total amount of Cr and Al, and the average content ratio y _avg of C in the total amount of C and N (where x _avg and y _avg are both atomic ratios) are 0.5. It is preferable to control so as to satisfy 70≦x _avg ≦0.95 and 0≦y _avg ≦0.005.
The reason for this is that if the average Al content x _avg is less than 0.70, the high-temperature hardness of the composite nitride or composite carbonitride layer of Cr and Al is insufficient and the oxidation resistance is also poor. Wear resistance is not sufficient when subjected to high-speed interrupted cutting of alloy steel or the like. On the other hand, when the average Al content x _avg exceeds 0.95, the average Cr content decreases relatively, which causes embrittlement and lowers the chipping resistance. Therefore, the average Al content x _avg is set to 0.70≦x _avg ≦0.95.
Further, when the average content ratio (atomic ratio) y _avg of the C component contained in the composite nitride or composite carbonitride layer is a trace amount in the range of 0 ≤ y _avg ≤ 0.005, the composite nitride or composite carbon The adhesion between the nitride layer and the tool substrate or lower layer is improved, and the lubricity is improved, thereby reducing the impact during cutting, and as a result, the chipping resistance and chipping resistance of the composite nitride or composite carbonitride layer are improved. Chipping resistance is improved. On the other hand, when the average content ratio y of the C component deviates from the range of 0 ≤ y _avg ≤ 0.005, the toughness of the composite nitride or composite carbonitride layer decreases, so the fracture resistance and chipping resistance decrease. It is not preferable because Therefore, the average content ratio y _avg of the C component was defined as 0≦y _avg ≦0.005.
(2) Composite nitride or composite carbonitride layer of Ti, Al, and Me according to the embodiment of the present invention Composition formula: (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) (where Me is a kind of element selected from Si, Zr, B, V, and Cr), the average content ratio α _avg of Al in the total amount of Ti and Al and Me and Ti of Me and The average content ratio β _avg in the total amount of Al and Me and the average content ratio γ _{avg of C in the total amount of C and N (} where α _avg , β _avg , and γ _avg are all atomic ratios) are, respectively, It is preferable to control to satisfy 0.60≦α _avg , 0.005≦β _avg ≦0.10, 0≦γ _avg ≦0.005, and 0.605≦α _avg +β _avg ≦0.95.
The reason for this is that if the average content ratio α _avg of Al is less than 0.60, the composite nitride or composite carbonitride layer of Ti, Al and Me is inferior in hardness, so that it is not suitable for high-speed intermittent cutting of alloy steel and the like. If it is used, the wear resistance is not sufficient.
In addition, when the average content ratio β _avg of Me is less than 0.005, the composite nitride or composite carbonitride layer 2 of Ti, Al, and Me is inferior in hardness, so that it is suitable for high-speed intermittent cutting of alloy steel and the like. If so, the wear resistance is not sufficient. On the other hand, if it exceeds 0.10, the segregation of Me to the grain boundary, etc., reduces the toughness of the composite nitride or composite carbonitride layer of Ti, Al, and Me, and when subjected to high-speed interrupted cutting of alloy steel, etc. have insufficient chipping resistance. Therefore, the average content ratio β _avg of Me was defined as 0.005≦β _avg ≦0.10.
On the other hand, when the sum α _avg +β _avg of the average content ratio α _avg of Al and the average content ratio β _avg of Me is less than 0.605, the hardness of the composite nitride or composite carbonitride layer of Ti, Al, and Me is Therefore, when subjected to high-speed intermittent cutting of alloy steel, etc., the wear resistance is not sufficient. , the chipping resistance decreases. Therefore, the sum α _avg +β _avg of the average Al content α _avg and the average Me content β _avg was determined to be 0.605≦α _avg +β _avg ≦0.95.
Here, as a specific component of Me, one type of element selected from Si, Zr, B, V and Cr is used.
When Si component or B component is used as Me so that β _avg is 0.005 or more, the hardness of the composite nitride or composite carbonitride layer is improved, so that the wear resistance is improved. , the Zr component has the effect of strengthening the grain boundaries, the V component improves the toughness, further improving the chipping resistance, and the Cr component improves the oxidation resistance. , further extension of tool life is expected. However, for any component, when the average content ratio β _avg exceeds 0.10, the average content ratio of the Al component and the Ti component relatively decreases, so the wear resistance or chipping resistance tends to decrease. Therefore, it is necessary to avoid an average content ratio in which β _avg exceeds 0.10.
In addition, when the average content ratio (atomic ratio) γ _avg of C contained in the composite nitride or composite carbonitride layer is a trace amount in the range of 0 ≤ γ _avg ≤ 0.005, the composite nitride or composite carbonitride layer The adhesion between the material layer and the tool substrate or lower layer is improved, and the impact during cutting is reduced by improving the lubricity, and as a result, the chipping resistance and resistance of the composite nitride or composite carbonitride layer are improved. Chipping resistance is improved. On the other hand, if the average C content γ _avg is outside the range of 0 ≤ γ _avg ≤ 0.005, the toughness of the composite nitride or composite carbonitride layer decreases, resulting in a decrease in fracture resistance and chipping resistance. It is not preferable because Therefore, the average content ratio γ _avg of C is defined as 0≦γ _avg ≦0.005.

で表すことができる。
なお、結晶粒内平均方位差、ＧＯＳ値は、結晶粒内のあるピクセルと、同一結晶粒内の他のすべてのピクセル間での方位差を求め、その値を平均化した数値であると言い換えることができるが、結晶粒内に連続的な方位変化が多いと大きな数値となる。 Average misorientation (GOS value) in individual crystal grains having a NaCl-type face-centered cubic structure that constitutes a composite nitride or composite carbonitride layer:
A crystal having a NaCl-type face-centered cubic structure constituting a composite nitride or composite carbonitride layer of Cr and Al as an embodiment (aspect) of the reference coated tool of the present invention using an electron beam backscatter diffraction apparatus. Crystal grains having an average orientation difference in the grains (cubic crystals) and a NaCl-type face-centered cubic structure that constitutes the composite nitride or composite carbonitride layer of Ti, Al and Me of the coated tool of the present invention ( The average misorientation in crystal grains of a cubic crystal) is obtained.
Specifically, a composite nitride or composite carbonitride layer of Cr and Al as an embodiment (aspect) of the reference coated tool of the present invention, or Ti as an embodiment (aspect) of the coated tool of the present invention and Al and Me composite nitride or composite carbonitride layers, respectively, are analyzed from the direction perpendicular to the surface at intervals of 0.1 μm on the surface polished surface, and as shown in FIG. 1, the adjacent measurement points ( Hereafter, when there is an orientation difference of 5 degrees or more between (also referred to as "pixels"), it is defined as a grain boundary. A region surrounded by grain boundaries is defined as one crystal grain. However, a single pixel that has an orientation difference of 5 degrees or more with respect to all adjacent pixels is not treated as a crystal grain, but a crystal grain in which two or more pixels are connected is treated as a crystal grain.
Then, the misorientation between a pixel in a crystal grain having a cubic crystal structure and all other pixels in the same crystal grain is calculated, obtained as the misorientation in the crystal grain, and averaged. is defined as the GOS (Grain Orientation Spread) value. A schematic diagram is shown in FIG. The GOS value is described, for example, in the document "Journal of the Japan Society of Mechanical Engineers, Vol.
In the embodiment (mode) of the reference coated tool of the present invention and the embodiment (mode) of the coated tool of the present invention, the "average misorientation in crystal grains" means the GOS value described above. When the GOS value is represented by a formula, n is the number of pixels within the same crystal grain, i and j are numbers assigned to different pixels within the same crystal grain (where 1≤i and j≤n), and pixel i Let α _{ij (i≠j)} be the crystal orientation difference obtained from the crystal orientation at pixel j and the crystal orientation at pixel j.

can be expressed as
In addition, the average misorientation within a crystal grain, or the GOS value, is a numerical value obtained by averaging the misorientation values between a certain pixel within a crystal grain and all other pixels within the same crystal grain. However, if there are many continuous orientation changes in the crystal grains, the value will be large.

The average misorientation (GOS value) within the crystal grain is within a measurement range of 25 × 25 μm from the direction perpendicular to the surface of the composite nitride or composite carbonitride layer on the polished surface using an electron beam backscattering diffraction device. Measurement is performed at intervals of 0.1 μm / step in 5 fields of view, and the total number of pixels belonging to the crystal grains having a cubic crystal structure that constitutes the composite nitride or composite carbonitride layer is obtained. By dividing the average misorientation at intervals of 1 degree, summing up the pixels of the crystal grains containing the average misorientation within the grain within the range of the values, and dividing by the above total number of pixels, the average misorientation within the grain is obtained. It can be obtained by creating a histogram showing the area ratio.
3 to 6 show examples of histograms created in this way.

(1) Composite nitride or composite carbonitride layer of Cr and Al that is a reference embodiment of the present invention FIG. 3 is a composite nitride or composite carbonitride layer of Cr and Al that is a reference embodiment of the present invention Fig. 3 is an example of a histogram of the average orientation difference within the crystal grains obtained for the crystal grains having a cubic crystal structure. It can be seen that a certain crystal grain accounts for 40% or more of the total area of the composite nitride or composite carbonitride layer of Cr and Al.
FIG. 4 shows the crystal grains having a cubic crystal structure of a conventional Cr and Al composite nitride or composite carbonitride layer in a reference comparison coated tool, which is a comparative example of the reference embodiment of the present invention . An example of a histogram of the average misorientation, in FIG. 4, the crystal grains having the value of the average misorientation (GOS) in the grains of 2 degrees or more are composite nitrides or composite carbonitride layers of Cr and Al. The area ratio to the total area is less than 40%.
As described above, the crystal grains having a cubic crystal structure constituting the composite nitride or composite carbonitride layer of Cr and Al, which is a reference embodiment of the present invention, have a crystal grain within the crystal grain compared to the conventional one. The variation in orientation is large, so the strain in the crystal grains is high, which contributes to the improvement of hardness and toughness, as well as the improvement of wear resistance.
Then, a hard coating layer, which is a reference embodiment of the present invention including at least a (Cr _1-x Al _x )(C _y N _1-y ) layer having the average orientation difference in crystal grains, was formed on the surface of the tool substrate. Coated tools exhibit excellent chipping resistance and wear resistance in high-speed intermittent cutting of alloy steel, etc., in which high heat is generated and an impact load acts on the cutting edge.
However, when the area ratio of the crystal grains showing the average orientation difference in the crystal grains of 2 degrees or more to the total area of the composite nitride or composite carbonitride layer of Cr and Al is less than 40%, the crystal Since the effect of improving the hardness and toughness due to the internal strain of the grain is not sufficient, the crystal grain having a cubic crystal structure exhibiting an average orientation difference in the grain of 2 degrees or more is a composite nitride or composite carbonitride layer of Cr and Al. The area ratio of the total area of is 40% or more.
The area ratio of crystal grains exhibiting an average misorientation in crystal grains of 2 degrees or more to the area of the composite nitride or composite carbonitride layer is preferably 45 to 70%. More preferably, the area ratio of crystal grains exhibiting an average misorientation in crystal grains of 2 degrees or more to the area of the composite nitride or composite carbonitride layer is 50 to 65%.

(2) Composite nitride or composite carbonitride layer of Ti, Al and Me, which is an embodiment of the present invention FIG. FIG. 5 is an example of a histogram of the average orientation difference within the crystal grains obtained for the crystal grains having the cubic crystal structure of the monolayer. As shown in FIG. It can be seen that the above crystal grains account for 40% or more of the total area of the composite nitride or composite carbonitride layer of Ti, Al and Me.
FIG. 6 shows the grains having a cubic crystal structure of a conventional composite nitride or composite carbonitride layer of Ti, Al, and Me in a comparative coated tool, which is a comparative example of the embodiment of the present invention . An example of the histogram of the average misorientation, in FIG. 6, the crystal grains having the value of the average misorientation (GOS) in the grains of 2 degrees or more are composite nitrides or composite carbonitrides of Ti, Al, and Me The area percentage of the total area of the layer is less than 40%.
As described above, the crystal grains having a cubic crystal structure that constitute the composite nitride or composite carbonitride layer of Ti, Al, and Me according to the embodiment of the present invention have a higher The variation in crystal orientation is large, which contributes to the improvement of hardness and toughness due to the high strain in the crystal grains.
Then, a hard coating layer, which is an embodiment of the present invention including at least a (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) layer having the average orientation difference in crystal grains, is formed on the surface of the tool substrate. A coated tool with a coating exhibits excellent chipping resistance and wear resistance in high-speed interrupted cutting of alloy steel, etc., in which high heat is generated and an impact load acts on the cutting edge.
However, when the area ratio of the crystal grains showing the average orientation difference in the crystal grains of 2 degrees or more to the total area of the composite nitride or composite carbonitride layer of Ti, Al and Me is less than 40% Since the effect of improving hardness and toughness due to the internal strain of the crystal grains is not sufficient, the crystal grains having a cubic crystal structure exhibiting an average orientation difference in the crystal grains of 2 degrees or more are composite nitrides or composites of Ti, Al, and Me. The area ratio of the carbonitride layer to the total area is set to 40% or more.
As described above, the crystal grains constituting the composite nitride or composite carbonitride layer of Al, Ti and Me possessed by the surface-coated cutting tool according to the embodiment of the present invention are different from the crystal grains constituting the conventional TiAlN layer. In comparison, crystal orientation variation within crystal grains is large, that is, there is strain, which contributes to improvement in hardness and toughness.
The area ratio of crystal grains exhibiting an average misorientation in crystal grains of 2 degrees or more to the area of the composite nitride or composite carbonitride layer is preferably 45 to 70%. More preferably, the area ratio of crystal grains exhibiting an average misorientation in crystal grains of 2 degrees or more to the area of the composite nitride or composite carbonitride layer is 50 to 65%.

Crystal structure of the hard coating layer:
(1) Composite nitride or composite carbonitride layer of Cr and Al, which is a reference embodiment of the present invention
When the composite nitride or composite carbonitride layer of Cr and Al, which is a reference embodiment of the present invention, consists of a single phase of a composite nitride or composite carbonitride of Cr and Al having a NaCl-type face-centered cubic structure , shows particularly excellent chipping resistance and wear resistance.
Further, even if the composite nitride or composite carbonitride layer of Cr and Al is not a NaCl-type face-centered cubic structure single phase, the composite nitride or composite carbonitride layer of Cr and Al can be electron Analyze at intervals of 0.1 μm from the longitudinal cross-sectional direction using a linear backscatter diffraction device, measure from the longitudinal cross-sectional direction within the measurement range of 10 μm width and film thickness in 5 fields of view, and the composite nitride Alternatively, the total number of pixels belonging to crystal grains having a cubic crystal structure that constitutes the composite carbonitride layer is obtained, and the composite nitride or the composite nitride or When the area ratio of the NaCl-type face-centered cubic structure crystal grains constituting the composite carbonitride layer is obtained, when the area ratio of the NaCl-type face-centered cubic structure crystal grains is less than 70 area%, the resistance On the other hand, when this area ratio is 70 area % or more, excellent chipping resistance and wear resistance are exhibited, so the NaCl type face-centered cubic structure Cr The ratio of the composite nitride or composite carbonitride phase of Al and Al is desirably 70 area % or more.
(2) Composite nitride or composite carbonitride layer of Ti, Al and Me according to the embodiment of the present invention
Particularly excellent wear resistance is exhibited when the hard coating layer comprising a composite nitride or composite carbonitride layer of Ti, Al and Me, which is an embodiment of the present invention, is a cubic crystal structure single phase.
In addition, even if the hard coating layer is not a single phase with a cubic crystal structure, the hard coating layer is analyzed at intervals of 0.1 μm from the longitudinal cross-sectional direction using an electron beam backscatter diffraction device, and the width is 10 μm and the length is Measurement from the vertical cross-sectional direction within the film thickness measurement range is performed in 5 fields of view, and the total number of pixels belonging to the crystal grains having a cubic crystal structure that constitutes the composite nitride or composite carbonitride layer is obtained. When the area ratio of the crystal grains having a cubic crystal structure constituting the composite nitride or composite carbonitride layer is obtained by the ratio to the total number of pixels measured in the measurement of the hard coating layer in 5 fields of view, the cubic crystal When the area ratio of structured crystal grains is less than 70%, wear resistance tends to decrease, while when this area ratio is 70% or more, excellent chipping resistance and wear resistance are obtained. It is desirable that the phase of the composite nitride or composite carbonitride of Ti, Al and Me having a cubic crystal structure is 70 area % or more.

Bottom layer and top layer:
The composite nitride or composite carbonitride layer of Cr and Al, which is a reference embodiment of the present invention, and the composite nitride or composite carbonitride layer of Ti, Al, and Me, which is an embodiment of the present invention, are Although it has a sufficient effect, it consists of one or more Ti compound layers selected from Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride layer. If the lower layer is provided with a total average layer thickness of 20 μm and/or if the upper layer containing at least the aluminum oxide layer is provided with a total average layer thickness of 1 to 25 μm, the effects of these layers and Together, it is possible to create even better characteristics. When providing a lower layer consisting of one or more Ti compound layers selected from Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride layer, the total average layer of the lower layer If the thickness is less than 0.1 μm, the effect of the lower layer is not sufficiently exhibited, while if it exceeds 20 μm, crystal grains tend to coarsen and chipping tends to occur. If the total average layer thickness of the upper layer including the aluminum oxide layer is less than 1 μm, the effect of the upper layer is not sufficiently exhibited. .

A composite nitride or composite carbonitride layer of Cr and Al that constitutes the hard coating layer that is an embodiment of the reference coated tool of the present invention, or Ti that constitutes an embodiment of the hard coating layer of the coated tool of the present invention FIG. 2 shows a schematic cross-sectional view of a composite nitride or composite carbonitride layer of Al and Me.

Next, the coated tool of the present invention will be specifically described with reference to examples , and the reference coated tool of the present invention, which is a reference embodiment, will be specifically described with reference examples.
As examples and reference examples, a coated tool using a WC-based cemented carbide or a TiCN-based cermet as a tool substrate will be described. be.

<Reference example 1>
As raw material powders, WC powder, TiC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder, all having an average particle size of 1 to 3 μm, were prepared. After blending with the composition, wax is further added and mixed in a ball mill for 24 hours in acetone, dried under reduced pressure, and then pressed into a green compact of a predetermined shape at a pressure of 98 MPa. Vacuum sintering is performed at a predetermined temperature within the range of ~1470°C for 1 hour, and after sintering, WC-based cemented carbide tool substrates A to C having an insert shape of ISO standard SEEN1203AFSN are produced respectively. did.

As raw material powders, TiCN (TiC/TiN=50/50 by mass ratio) powder, Mo ₂ C powder, ZrC powder, NbC powder, WC powder, and Co powder, all having an average particle size of 0.5 to 2 μm. and Ni powder are prepared, these raw material powders are blended in the formulation shown in Table 2, wet-mixed in a ball mill for 24 hours, dried, and then pressed into a green compact at a pressure of 98 MPa. The body was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1500° C. for 1 hour. After sintering, a TiCN-based cermet tool base D having an insert shape of ISO standard SEEN1203AFSN was produced.

Next, using a chemical vapor deposition apparatus on the surfaces of these tool substrates A to D,
Formation conditions A to J shown in Tables 4 and 5, that is, gas group A consisting of NH ₃ and H ₂ and gas group B consisting of CrCl ₃ , AlCl ₃ , N ₂ and H ₂ , and supply of each gas As a method, the reaction gas composition (% by volume of the total of gas group A and gas group B) was prepared as gas group A: NH ₃ : 2.0 to 3.0%, H ₂ : 65 to 75%, gas group AlCl ₃ as B: 0.6-0.9%, CrCl ₃ : 0.2-0.3%, Al(CH ₃ ) ₃ : 0-0.5%, N ₂ : 12.5-15.0 %, H ₂ : remainder, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 700 to 900° C., supply cycle 3 to 4 seconds, gas supply time per cycle 0.15 to 0.25 seconds , the phase difference between the gas group A and the gas group B is set to 0.10 to 0.20 seconds, and the thermal CVD method is performed for a predetermined time. A hard coating layer containing a (Cr _1-x Al _x ) (C _y N _1-y ) layer having crystal grains having a crystal structure in the area ratio shown in Table 7 and having the target layer thickness shown in Table 7 Reference coated tools 1-15 of the present invention were produced by forming.
For reference coated tools 6 to 13 of the present invention, the lower layer shown in Table 6 and/or the upper layer shown in Table 7 were formed under the formation conditions shown in Table 3.

In addition, for the purpose of comparison, the reference coated tool of the present invention was subjected to the formation conditions A' to J' of the reference comparative film formation process shown in Tables 4 and 5 and Table 8 on the surfaces of the tool substrates A to D. A hard coating layer containing at least a composite nitride or composite carbonitride layer of Cr and Al was vapor-deposited with a target layer thickness (μm) shown in FIG. At this time, a hard coating layer is formed so that the reaction gas composition on the surface of the tool substrate does not change with time during the process of forming the (Cr _1-x Al _x ) (C _y N _1-y ) layer. Comparative coated tools 1-13 were made.
As with the reference coated tools 6 to 13 of the present invention, for the reference comparative coated tools 6 to 13, under the forming conditions shown in Table 3, the lower layer shown in Table 6 and/or the upper layer shown in Table 8 formed a layer.

For reference, a (Cr _1-x Al _x )(C _y N _1-y ) layer of the reference example was formed on the surfaces of the tool substrate B and the tool substrate C by arc ion plating using a conventional physical vapor deposition apparatus. at the target layer thickness to produce the reference coated tools 14, 15 shown in Table 8.
The arc ion plating conditions used for vapor deposition in Reference Examples are as follows.
(a) The tool substrates B and C are ultrasonically cleaned in acetone, dried, and placed radially at a predetermined distance from the central axis on the rotary table in the arc ion plating apparatus. Also, as a cathode electrode (evaporation source), an Al-Cr alloy with a predetermined composition is arranged,
(b) First, while the inside of the apparatus is evacuated and maintained at a vacuum of 10 ⁻² Pa or less, the inside of the apparatus is heated to 500° C. with a heater, and then −1000 V is applied to the tool substrate rotating while rotating on the rotary table. is applied, and a current of 200 A is passed between the cathode electrode and the anode electrode made of Al--Cr alloy to generate arc discharge, generate Al and Cr ions in the device, and thereby the tool substrate Bombard clean the surface,
(c) Next, nitrogen gas is introduced into the apparatus as a reaction gas to create a reaction atmosphere of 4 Pa, and a DC bias voltage of −50 V is applied to the tool base rotating while rotating on the rotary table, and , A current of 120 A is passed between the cathode electrode (evaporation source) made of the Al-Cr alloy and the anode electrode to generate an arc discharge, and the target composition shown in Table 8 and the target layer are applied to the surface of the tool substrate. A thick (Cr _1-x Al _x )(C _y N _1-y ) layer was deposited to fabricate reference coated tools 14,15.

In addition, cross sections in the direction perpendicular to the tool substrate of each constituent layer of the reference coated tools 1 to 15, reference comparative coated tools 1 to 13, and reference coated tools 14 and 15 of the present invention were examined with a scanning electron microscope (magnification: 5000). , and the average layer thickness was obtained by measuring the layer thickness at five points in the observation field, and the average layer thickness was substantially the same as the target layer thickness shown in Tables 6 to 8. showed that.

In addition, the average Al content x _avg of the composite nitride or composite carbonitride layer was measured using an electron-probe-micro-analyser (EPMA) in a sample whose surface was polished. The average Al content x _avg of Al was obtained from the 10-point average of the characteristic X-ray analysis results obtained by irradiating from the surface side. The average C content y _avg was determined by secondary-ion-mass-spectroscopy (SIMS). An ion beam was irradiated in a range of 70 μm×70 μm from the sample surface side, and the concentration in the depth direction was measured for the components emitted by the sputtering action. The average C content ratio y _avg indicates an average value in the depth direction of the composite nitride or composite carbonitride layer of Cr and Al. However, the content ratio of C excludes the unavoidable content ratio of C that is included even if a gas containing C is not intentionally used as a gas raw material. Specifically, the content ratio (atomic ratio) of the C component contained in the composite nitride or composite carbonitride layer when the supply amount of Al(CH ₃ ) ₃ is 0 is obtained as the inevitable C content ratio. , the unavoidable C content ratio was subtracted from the content ratio (atomic ratio) of the C component contained in the composite nitride or composite carbonitride layer obtained when Al(CH ₃ ) ₃ was intentionally supplied. The value was determined as _yavg .

In addition, the crystal orientation of individual crystal grains having a cubic crystal structure that constitutes the composite nitride or carbonitride layer of Cr and Al is analyzed from the longitudinal cross-sectional direction using an electron beam backscatter diffraction device, and the adjacent pixels If there is an orientation difference of 5 degrees or more between the The crystal grain orientation difference is determined between 0 degrees and less than 1 degree, 1 degree and less than 2 degrees, 2 degrees and less than 3 degrees, 3 degrees and less than 4 degrees, and so on. The range of 10 degrees was separated by 1 degree and mapped. From the mapping diagram, the area ratio of crystal grains having an average misorientation in the crystal grains of 2 degrees or more in the entire Cr-Al composite nitride or composite carbonitride layer was determined.
FIG. 3 shows an example of the histogram of the average grain orientation difference measured for the reference coated tool of the present invention, and FIG. 4 shows an example of the histogram of the average grain orientation difference measured for the reference comparative coated tool. indicates
Furthermore, the composite nitride or composite carbonitride layer of Cr and Al is analyzed at intervals of 0.1 μm from the longitudinal cross-sectional direction using an electron beam backscatter diffraction device, the width is 10 μm, and the vertical is within the measurement range of the film thickness. Measurement from the longitudinal cross-sectional direction is carried out in 5 fields of view, the total number of pixels belonging to the crystal grains having a cubic crystal structure that constitutes the composite nitride or composite carbonitride layer is obtained, and in the measurement in the 5 fields of view, all Depending on the ratio to the number of measured pixels, the NaCl-type face-centered cubic crystal grains constituting the composite nitride or composite carbonitride layer are in the longitudinal section of the Cr and Al composite nitride or composite carbonitride layer. The area ratio (area %) occupied was determined.
Tables 7 and 8 show these results.

Next, with each of the various coated tools described above being clamped to the tip of a tool steel cutter having a cutter diameter of 125 mm with a fixing jig, reference coated tools 1 to 15 of the present invention, reference comparative coated tools 1 to 13, and The reference coated tools 14 and 15 were subjected to the following high-speed dry face milling and center-cut cutting tests, which are a type of high-speed interrupted cutting of carbon steel, and the flank wear width of the cutting edge was measured.
Tool substrate: Tungsten carbide-based cemented carbide, titanium carbonitride-based cermet,
Cutting test: dry high-speed face milling, center cut machining,
Work material: JIS/S55C block material with a width of 100 mm and a length of 400 mm,
Rotation speed: 815 min ^-1 ,
Cutting speed: 320 m/min,
Notch: 1.0 mm,
Single blade feed amount: 0.1 mm/blade,
Cutting time: 8 minutes,
Table 9 shows the results.

<Reference example 2>
As raw material powders, WC powder, TiC powder, ZrC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder and Co powder, all having an average particle size of 1 to 3 μm, were prepared. The blending composition shown in Table 10 was blended, further wax was added, ball mill mixed in acetone for 24 hours, dried under reduced pressure, and then press-molded into a green compact of a predetermined shape at a pressure of 98 MPa. Vacuum sintered in a vacuum of 5 Pa at a predetermined temperature within the range of 1370 to 1470 ° C. for 1 hour. Tool substrates α to γ made of WC-based cemented carbide with insert geometry of CNMG120412 were respectively produced.

In addition, as raw material powders, TiCN (TiC/TiN=50/50 by mass ratio) powder, NbC powder, WC powder, Co powder, and Ni powder, all of which have an average particle size of 0.5 to 2 μm, are prepared, These raw material powders were blended in the formulation shown in Table 11, wet-mixed in a ball mill for 24 hours, dried, and then press-molded into a green compact at a pressure of 98 MPa. Sintered in an atmosphere at a temperature of 1500°C for 1 hour. After sintering, the cutting edge was honed to a radius of 0.09 mm to obtain a TiCN base with an insert shape conforming to ISO standard CNMG120412. A tool base δ made of cermet was formed.

Next, on the surfaces of these tool substrates α to γ and tool substrate δ, using a chemical vapor deposition apparatus, the formation conditions of the reference film formation process of the present invention shown in Tables 4 and 5 are applied in the same manner as in Reference Example 1. Reference coated tools of the present invention shown in Table 13 by depositing a hard coat layer comprising at least a (Cr _1-x Al _x )(C _y N _1-y ) layer in A to J to a target layer thickness. 16-30 were produced.
For reference coated tools 19 to 28 of the present invention, the lower layer shown in Table 12 and/or the upper layer shown in Table 13 were formed under the formation conditions shown in Table 3.

For the purpose of comparison, a chemical vapor deposition apparatus was also used on the surfaces of the tool substrates α to γ and the tool substrate δ, and the formation conditions A′ to J′ of the reference comparative film formation process shown in Tables 4 and 5 and Table Reference comparative coated tools 16-28 shown in Table 14 were produced by depositing a hardcoat layer with the target layer thickness shown in Table 14.
As with the reference coated tools 19 to 28 of the present invention, for the reference comparative coated tools 19 to 28, under the forming conditions shown in Table 3, the lower layer shown in Table 12 and/or the upper layer shown in Table 14 formed a layer.

For reference, a (Cr _1-x Al _x )(C _y N _1-y ) layer of the reference example was formed on the surfaces of the tool substrate β and the tool substrate γ by arc ion plating using a conventional physical vapor deposition apparatus. to a target layer thickness to produce reference coated tools 29 and 30 shown in Table 14.
The same arc ion plating conditions as those shown in Reference Example 1 were used.

In addition, the section of each constituent layer of the reference coated tools 16 to 30, the reference comparative coated tools 16 to 28, and the reference coated tools 29 and 30 of the present invention was measured using a scanning electron microscope (magnification: 5,000 times), and the observation field of view was When the average layer thickness was obtained by measuring the layer thickness at five points inside, the average layer thickness was substantially the same as the target layer thickness shown in Tables 12 to 14.

In addition, the crystal orientation of individual crystal grains having a cubic crystal structure that constitutes the composite nitride or carbonitride layer of Cr and Al is analyzed from the longitudinal cross-sectional direction using an electron beam backscatter diffraction device, and the crystal grains 0 to 1 degree, 1 to 2 degrees, 2 to 3 degrees, 3 to 4 degrees, and so on. did. From the mapping diagram, the area ratio of crystal grains having an average intra-grain orientation difference and an intra-grain orientation difference of 2 degrees or more in the entire Cr-Al composite nitride or composite carbonitride layer was determined.
Furthermore, the area ratio of the NaCl-type face-centered cubic structure crystal grains constituting the Cr and Al composite nitride or composite carbonitride layer to the longitudinal section of the Cr and Al composite nitride or composite carbonitride layer Tables 13 and 14 show the results of determining (area %).

Next, the reference coated tools 16 to 30 of the present invention, the reference comparative coated tools 16 to 28, and the reference coated tools were prepared in a state in which each of the various coated tools was screwed to the tip of the tool steel cutting tool with a fixing jig. Tools 29 and 30 were subjected to the following carbon steel dry high-speed interrupted cutting test and ductile cast iron wet high-speed interrupted cutting test, and the flank wear width of the cutting edge was measured in both cases.
Cutting condition 1:
Work material: JIS S55C round bar with 4 equally spaced longitudinal grooves,
Cutting speed: 345m/min,
Notch: 2.0 mm,
feed: 0.1mm/rev,
Cutting time: 5 minutes,
(Normal cutting speed is 220m/min),
Cutting condition 2:
Work material: JIS FCD700 round bar with 4 equally spaced longitudinal grooves,
Cutting speed: 325m/min,
Notch: 1.5 mm,
feed: 0.1mm/rev,
Cutting time: 5 minutes,
(Normal cutting speed is 180m/min),
Table 15 shows the results of the cutting test.

From the results shown in Tables 9 and 15, the reference coated tools 1 to 15 and 16 to 30 of the present invention have a cubic crystal structure constituting a composite nitride or composite carbonitride layer of Cr and Al. In the above, the presence of a predetermined average orientation difference in crystal grains improves hardness due to distortion of crystal grains, and improves toughness while maintaining high wear resistance. Moreover, even when used in high-speed interrupted cutting where high intermittent and impact loads act on the cutting edge, it has excellent chipping resistance and fracture resistance, resulting in excellent wear resistance over long-term use. It is clear that it works.

On the other hand, in the crystal grains having a cubic crystal structure constituting the composite nitride or carbonitride layer of Cr and Al constituting the hard coating layer, there is no predetermined average orientation difference within the crystal grains. The reference comparative coated tools 1 to 13, 16 to 28 and the reference coated tools 14, 15, 29, and 30 are used for high-speed interrupted cutting that involves high heat generation and intermittent/impact high load acting on the cutting edge. When used, it is clear that chipping, breakage, and the like occur in a short period of time.

<Example 1>
As raw material powders, WC powder, TiC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder, all having an average particle size of 1 to 3 μm, were prepared. After blending with the composition, wax is further added and mixed in a ball mill for 24 hours in acetone, dried under reduced pressure, and then pressed into a green compact of a predetermined shape at a pressure of 98 MPa. Vacuum sintering is performed at a predetermined temperature within the range of ~1470°C for 1 hour, and after sintering, WC-based cemented carbide tool substrates E to G having an insert shape of ISO standard SEEN1203AFSN are produced respectively. did.

As raw material powders, TiCN (TiC/TiN=50/50 in mass ratio) powder, Mo ₂ C powder, ZrC powder, NbC powder, WC powder, and Co powder, all having an average particle size of 0.5 to 2 μm. and Ni powders are prepared, these raw material powders are blended in the formulation shown in Table 17, wet-mixed in a ball mill for 24 hours, dried, and then pressed into a green compact at a pressure of 98 MPa. The body was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1500° C. for 1 hour. After sintering, a TiCN-based cermet tool base H having an insert shape of ISO standard SEEN1203AFSN was produced.

Next, on the surfaces of these tool substrates E to H, using a chemical vapor deposition apparatus, the formation conditions shown as the film formation process of the present invention in Tables 19 and 20, that is, gas group A consisting of NH ₃ and H ₂ and , TiCl ₄ , Al(CH ₃ ) ₃ , AlCl ₃ , MeCl _n (any one of SiCl ₄ , ZrCl ₄ , BCl ₃ , VCl ₄ and CrCl ₂ ), N ₂ and H ₂ , and each gas supply method, the reaction gas composition (% by volume of the total of gas group A and gas group B) is NH ₃ : 2.0 to 3.0%, H ₂ : 65% for gas group A ~75%, gas group B: AlCl ₃ : 0.6 to 0.9%, TiCl ₄ : 0.2 to 0.3%, Al(CH ₃ ) ₃ : 0 to 0.5%, MeCl _n (however, , SiCl ₄ , ZrCl ₄ , BCl ₃ , VCl ₄ , or CrCl ₂ ): 0.1-0.2%, N ₂ : 12.5-15.0%, H ₂ : remainder, reaction atmosphere Pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 700 to 900° C., supply cycle 1 to 5 seconds, gas supply time per cycle 0.15 to 0.25 seconds, gas group A and gas group B Thermal CVD is performed for a predetermined time with a supply phase difference of 0.10 to 0.20 seconds. and having the target layer thickness shown in Table 22 (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ). Invention coated tools 31-45 were manufactured.
For the coated tools 36 to 43 of the present invention, the lower layer shown in Table 21 and/or the upper layer shown in Table 22 were formed under the formation conditions shown in Table 18.

For the purpose of comparison, the coated tool 31 of the present invention was applied to the surfaces of the tool substrates E to H under the conditions shown in Tables 19 and 20 as the comparative film forming process and the target layer thickness (μm) shown in Table 23. 45, a hard coating layer containing at least a compound nitride or compound carbonitride layer of Ti and Al was vapor-deposited. At this time, a hard coating layer is formed so that the reaction gas composition on the surface of the tool substrate does not change with time during the process of forming the (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) layer. Comparative coated tools 31-45 were produced by doing so.
As with the coated tools 36 to 43 of the present invention, the lower layers shown in Table 21 and/or the upper layers shown in Table 23 were formed under the formation conditions shown in Table 18 for the comparative coated tools 36 to 43. did.

In addition, the cross section of each component layer of the coated tools 31 to 45 of the present invention and the comparative coated tools 31 to 45 in the direction perpendicular to the tool substrate was measured using a scanning electron microscope (magnification: 5000 times). When the layer thickness was measured at five points and averaged to find the average layer thickness, all of them showed substantially the same average layer thickness as the target layer thickness shown in Tables 21 to 23.

In addition, the average Al content and the average Me content of the composite nitride or composite carbonitride layer were measured using an electron-probe-micro-analyser (EPMA) in a sample whose surface was polished. The average Al content α _avg and the average Me content β _avg were obtained from the 10-point average of the characteristic X-ray analysis results obtained by irradiating the sample from the surface side. The average C content γ _avg was determined by secondary-ion-mass-spectroscopy (SIMS). An ion beam was irradiated in a range of 70 μm×70 μm from the sample surface side, and the concentration in the depth direction was measured for the components emitted by the sputtering action. The average C content ratio γ _avg indicates the average value in the depth direction of the composite nitride or composite carbonitride layer of Ti, Al and Me. However, the content ratio of C excludes the unavoidable content ratio of C that is included even if a gas containing C is not intentionally used as a gas raw material. Specifically, the content ratio (atomic ratio) of the C component contained in the composite nitride or composite carbonitride layer when the supply amount of Al(CH ₃ ) ₃ is 0 is obtained as the inevitable C content ratio. , the unavoidable C content ratio was subtracted from the content ratio (atomic ratio) of the C component contained in the composite nitride or composite carbonitride layer obtained when Al(CH ₃ ) ₃ was intentionally supplied. Values were determined as γ _avg .

Furthermore, the crystal orientation of individual crystal grains having a cubic crystal structure that constitutes the composite nitride or composite carbonitride layer of Ti, Al, and Me is analyzed from the longitudinal cross-sectional direction using an electron beam backscatter diffractometer. If there is an orientation difference of 5 degrees or more between pixels, the grain boundary is defined as a grain boundary. The crystal grain orientation difference is obtained between pixels, and the crystal grain orientation difference is 0 degrees or more and less than 1 degree, 1 degree or more and less than 2 degrees, 2 degrees or more and less than 3 degrees, 3 degrees or more and less than 4 degrees, and so on. The range of 0 to 10 degrees was divided by 1 degree and mapped. From the mapping diagram, the area ratio of crystal grains having an average misorientation in the crystal grains of 2 degrees or more in the entire composite nitride or composite carbonitride layer of Ti, Al, and Me was determined. The results are shown in Tables 22 and 23.
FIG. 5 shows an example of a histogram of the average grain misorientation measured for the coated tool of the present invention, and FIG. 6 shows an example of a histogram of the average grain misorientation measured for the comparative coated tool.

Next, the coated tools 31 to 45 of the present invention and the comparative coated tools 31 to 45 were measured in a state where each of the various coated tools was clamped to the tip of a tool steel cutter having a cutter diameter of 125 mm with a fixing jig. A dry high-speed face milling and center-cut cutting test, which is a type of high-speed interrupted cutting of carbon steel, was performed to measure the flank wear width of the cutting edge. The results are shown in Table 24.

Tool substrate: Tungsten carbide-based cemented carbide, titanium carbonitride-based cermet,
Cutting test: dry high-speed face milling, center cut machining,
Work material: JIS/S55C block material with a width of 100 mm and a length of 400 mm,
Rotation speed: 815 min ^-1 ,
Cutting speed: 320 m/min,
Notch: 1.5 mm,
Single blade feed amount: 0.1 mm/blade,
Cutting time: 8 minutes,

<Example 2>
Using the same raw material powder as in Reference Example 2, mixing in the same composition (see Tables 10 and 11), and using the same manufacturing method (see paragraphs 0051 and 0052), the insert shape of ISO standard CNMG120412 was obtained. Tool substrates α to γ made of WC-based cemented carbide and tool substrate δ made of TiCN-based cermet were produced, respectively.

Next, on the surfaces of these tool substrates α to γ and tool substrate δ, using a chemical vapor deposition apparatus, the present invention film-forming process shown in Tables 19 and 20 was performed in the same manner as in Example 1 (see paragraph 0069). The coating of the present invention shown in Table 26 was formed by vapor-depositing a hard coating layer containing at least a (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) layer with a target layer thickness under the conditions of Tools 46-60 were manufactured.
For the coated tools 49 to 58 of the present invention, the lower layer shown in Table 25 and/or the upper layer shown in Table 26 were formed under the formation conditions shown in Table 18.

For the purpose of comparison, the surfaces of the tool substrates α to γ and the tool substrate δ were similarly subjected to the chemical vapor deposition apparatus under the conditions of the comparative film formation process shown in Tables 19 and 20 and the target layer thickness shown in Table 27. Comparative coated tools 46-60 shown in Table 27 were made by depositing a hard coat layer at .
As with the coated tools 49 to 58 of the present invention, the lower layers shown in Table 25 and/or the upper layers shown in Table 27 were formed under the formation conditions shown in Table 18 for the comparative coated tools 49 to 58. did.

In addition, the section of each constituent layer of the coated tools 46 to 60 of the present invention and the comparative coated tools 46 to 60 was measured using a scanning electron microscope (magnification of 5000 times), and the layer thickness was measured at five points within the observation field. When the average layer thickness was determined by averaging, all of them showed substantially the same average layer thickness as the target layer thicknesses shown in Tables 25 to 27.
Further, for the hard coating layers of the coated tools 46 to 60 of the present invention and the comparative coated tools 46 to 60, the average Al content α _avg and the average Me content β _avg , the average C content γ _avg , and the area ratio of the cubic crystal phase in the crystal grains were obtained.

Furthermore, the crystal orientation of individual crystal grains having a cubic crystal structure that constitutes the Ti and Al composite nitride or composite carbonitride layer is analyzed from the longitudinal cross-sectional direction using an electron beam backscatter diffraction device, and the crystal grains 0 degrees to less than 1 degree, 1 degree to less than 2 degrees, 2 degrees to less than 3 degrees, 3 degrees to less than 4 degrees, etc. did. From the mapping diagram, the area ratio of crystal grains having an average orientation difference in crystal grains and an orientation difference in crystal grains of 2 degrees or more in the entire composite nitride or composite carbonitride layer of Ti, Al, and Me was determined. The results are shown in Tables 26 and 27.

Next, the coated tools 46 to 60 of the present invention and the comparative coated tools 46 to 60 are shown below with each of the various coated tools screwed to the tip of the tool steel cutting tool with a fixing jig. A dry high-speed interrupted cutting test of carbon steel and a wet high-speed interrupted cutting test of cast iron were carried out, and the flank wear width of the cutting edge was measured in both cases.
Cutting condition 1:
Work material: JIS S55C round bar with 4 equally spaced longitudinal grooves,
Cutting speed: 355m/min,
Notch: 2.0 mm,
Feed: 0.12mm/rev,
Cutting time: 5 minutes,
(Normal cutting speed is 220m/min),
Cutting condition 2:
Work material: JIS FCD700 round bar with 4 equally spaced longitudinal grooves,
Cutting speed: 335m/min,
Notch: 1.5 mm,
Feed: 0.12mm/rev,
Cutting time: 5 minutes,
(Normal cutting speed is 180m/min),
Table 28 shows the results of the cutting test.

From the results shown in Tables 24 and 28, the coated tool of the present invention has a cubic crystal structure that constitutes a composite nitride or composite carbonitride layer of Al, Ti, and Me that constitutes the hard coating layer. In the above, the presence of a predetermined average orientation difference in crystal grains improves hardness due to distortion of crystal grains, and improves toughness while maintaining high wear resistance. Moreover, even when used in high-speed interrupted cutting where high intermittent and impact loads act on the cutting edge, it has excellent chipping resistance and fracture resistance, resulting in excellent wear resistance over long-term use. It is clear that it works.

On the other hand, in the crystal grains having a cubic crystal structure that constitute the composite nitride or composite carbonitride layer of Al, Ti, and Me that constitute the hard coating layer, there is a predetermined average orientation difference within the crystal grains. Regarding the comparative coated tools 31 to 45 and 46 to 60 that are not coated, when used for high-speed interrupted cutting that involves high heat generation and intermittent and impactful high loads act on the cutting edge, chipping, fracture, etc. It is clear that the life span is shortened by the

As described above, the coated tool of the present invention can be used not only for high-speed interrupted cutting of carbon steel, alloy steel, cast iron, etc., but also as a coated tool for various work materials. Since it exhibits excellent chipping resistance and wear resistance, it can satisfactorily meet demands for high performance cutting equipment, labor saving and energy saving in cutting, and cost reduction.

REFERENCE SIGNS LIST 1 tool substrate 2 hard coating layer 3 composite nitride or composite carbonitride layer

Claims (6)

A surface-coated cutting tool having a hard coating layer formed on the surface of a tool substrate made of any one of a tungsten carbide-based cemented carbide, a titanium carbonitride-based cermet, and a cubic boron nitride-based ultrahigh-pressure sintered body,
(a) the hard coating layer is a composite nitride of Ti, Al, and Me (where Me is one element selected from Si, Zr, B, V, and Cr) having an average layer thickness of 1 to 20 μm; or including at least a composite carbonitride layer,
its composition,
Composition formula: (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ )
, the average content ratio α _avg of Al in the total amount of Ti, Al, and Me in the composite nitride or composite carbonitride layer, and the average content ratio β _avg of Me in the total amount of Ti, Al, and Me and the average content ratio γ _avg of C in the total amount of C and N (where α _avg , β _avg , and γ _avg are all atomic ratios) are respectively 0.60 ≤ α _avg and 0.005 ≤ β _avg satisfying ≦0.10, 0≦γ _avg ≦0.005, 0.605≦α _avg +β _avg ≦0.95,
(b) the composite nitride or composite carbonitride layer includes at least a composite nitride or composite carbonitride phase having a NaCl-type face-centered cubic structure;
(c) The crystal orientation of the crystal grains of the composite nitride or composite carbonitride having a NaCl-type face-centered cubic structure among the crystal grains constituting the composite nitride or composite carbonitride layer is determined by electron beam backscattering. When the average misorientation in each crystal grain is obtained by analyzing from the longitudinal cross-sectional direction using a diffractometer, the crystal grains exhibiting the average misorientation in the crystal grain of 2 degrees or more are composite nitrides or composite carbons. A surface-coated cutting tool, wherein the nitride layer is present in an area ratio of 40% or more of the total area. 2. The composite nitride or composite carbonitride layer according to claim 1, wherein the composite nitride or composite carbonitride layer is composed of a single phase of a composite nitride or composite carbonitride of Ti, Al, and Me having a NaCl-type face-centered cubic structure. coated cutting tools. The composite nitride or composite carbonitride layer contains at least 70 area % or more of a composite nitride or composite carbonitride phase of Ti, Al and Me having a NaCl-type face-centered cubic structure. Item 3. The surface-coated cutting tool according to Item 1 or 2. Between the tool substrate and the composite nitride or composite carbonitride layer, one or more layers selected from Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride layer The surface-coated cutting tool according to any one of claims 1 to 3, characterized in that there is a lower layer consisting of a Ti compound layer of 0.1 to 20 µm in total average layer thickness. 5. Any one of claims 1 to 4, wherein an upper layer containing at least an aluminum oxide layer is formed on the composite nitride or composite carbonitride layer with a total average layer thickness of 1 to 25 μm. A surface-coated cutting tool as described. The surface-coated cutting tool according to any one of claims 1 to 5, wherein the composite nitride or composite carbonitride layer is formed by a chemical vapor deposition method containing at least trimethylaluminum as a reactive gas component. manufacturing method.

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