JP2018149668A - Surface coated cutting tool with hard coating layer exhibiting superior chipping resistance and abrasion resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface coated cutting tool exhibiting superior chipping resistance and abrasion resistance, when used for ultra high-speed intermittent cutting of alloy steel or the like.SOLUTION: The surface coated cutting tool is a cutting tool having a hard film containing(TiAlMe)(CN) (in which Me is at least one of Si or B, and 0.60≤x<0.95, 0.005≤y≤0.100, 0.60<x+y≤0.95, 0.0000≤z≤0.0050) on a tool base surface. In the surface coated cutting tool, an average content ratio s of Cl to a total amount of atoms constituting a TiAlMeCN phase is 0.0001≤s≤0.0040, and when calculating surface intervals d(111) and d(200) of crystal grains in a NaCl structure inside the TiAlMeCN layer and defining A(111)=3d(111) and A(200)=2d(200), an absolute value ΔA of a difference between A(111) and A(200) is 0.007Å≤ΔA≤0.050Å.SELECTED DRAWING: None

Description

  The present invention is an ultra-high-speed intermittent cutting process that involves high heat generation of alloy steel and the like, and an impact load is applied to the cutting edge. The hard coating layer has excellent chipping resistance and wear resistance. The present invention relates to a surface-coated cutting tool (hereinafter sometimes referred to as a coated tool) that exhibits excellent cutting performance over a long period of use.

Conventionally, generally composed of 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 There is known a coated tool in which a Ti—Al-based composite nitride layer is formed by physical vapor deposition as a hard coating layer on the surface of a tool substrate (hereinafter collectively referred to as a tool substrate), These are known to exhibit excellent wear resistance.
However, the conventional coated tool with the Ti-Al based composite nitride layer is relatively excellent in wear resistance, but is likely to cause abnormal wear such as chipping when used under high-speed intermittent cutting conditions. Therefore, various proposals for improving the hard coating layer have been made.

For example, Patent Document 1 has a NaCl-type face-centered cubic structure on the surface of a tool base and is represented by a composition formula: (Ti _1-X Al _X ) (C _Y N _1-Y ) (provided that the atomic ratio is The average composition X _{avg of} Al is 0.60 ≦ X _avg ≦ 0.95, the average composition Y _{avg of} C is 0 ≦ Y _avg ≦ 0.005) and a hard coating layer including at least a TiAlCN layer is formed, For the TiAlCN layer, using an electron beam backscattering diffractometer, the inclination angle number distribution was determined by measuring the inclination angle formed by the normal of the {111} face of the TiAlCN crystal grain with respect to the normal direction of the tool base surface, The highest peak is present in the inclination angle section within the range of 0 to 12 degrees, and the sum of the frequencies existing within the range of 0 to 12 degrees is 45% or more of the entire frequencies in the inclination angle frequency distribution, Furthermore, the in-plane perpendicular to the thickness direction of the TiAlCN layer A structure having a triangular shape and a facet formed by an equivalent crystal plane represented by {111} of the crystal grains occupies an area ratio of 35% or more of the whole in a plane perpendicular to the layer thickness direction. A coating tool with improved chipping resistance of a hard coating layer in high-speed interrupted cutting and the like that is accompanied by high heat generation such as stainless steel and an impact load on the cutting edge has been proposed. .

Further, in Patent Document 2, as in Patent Document 1, high heat generation of stainless steel or the like is accompanied, and chipping resistance of the hard coating layer in high-speed intermittent cutting processing in which an impact load is applied to the cutting edge. In order to increase the surface of the tool base, it is represented by the composition formula: (Ti _1-X Al _X ) (C _Y N _1-Y ) (however, in terms of atomic ratio, the average composition X _{avg of} Al is 0.60). ≦ X _avg ≦ 0.95, the average composition Y _{avg of} C is 0 ≦ Y _avg ≦ 0.005), and a hard coating layer including at least a TiAlCN layer having a NaCl-type face-centered cubic structure is formed, For the TiAlCN layer, using an electron beam backscatter diffractometer, the inclination angle number distribution was determined by measuring the inclination angle formed by the normal of the {100} plane of the TiAlCN crystal grains with respect to the normal direction of the tool base surface. Inclined angle in the range of 0-12 degrees The sum of the frequencies existing in the range of 0 to 12 degrees is 45% or more of the entire frequencies in the inclination angle distribution, and is perpendicular to the thickness direction of the TiAlCN layer. A polygonal facet having no angle of less than 90 degrees in the plane, the facet formed on one of the equivalent crystal planes represented by {100} of the crystal grains, the facet being a layer A coated tool having a structure that occupies an area ratio of 50% or more of the whole in a plane perpendicular to the thickness direction has been proposed.
Further, when XRD analysis is performed on the TiAlCN layer in the coated tool, Ic {200 between the peak intensity Ic {200} derived from the cubic structure and the peak intensity Ih {200} derived from the hexagonal structure. } / Ih {200} ≧ 3.0 holds true, the effect of improving wear resistance is further enhanced.

Further, in Patent Document 3, in order to improve the wear resistance of a tool, a 3 to 25 μm wear-resistant coating layer formed by CVD is formed on a tool substrate, and the coating layer includes at least Ti _1-1. when expressed in _x Al _x C _y N _z, the thickness of 1.5~17μm that satisfies 0.70 ≦ x <1,0 ≦ y < 0.25 and 0.75 ≦ z <1.15 Ti _1-x Al _x having a TiAlCN layer having a lamellar structure with a lamellar spacing of less than 150 nm, the cutting edge having the same crystal structure, and Ti and Al having different stoichiometry. C _y N _z is constituted by a periodically alternating arranged a _{Ti 1-x Al x C y} N z, _{further, Ti 1-x Al x C} y N z layer is at least 90 vol% or more is face-centered cubic The TC value of the layer is TC (111)> 1 5 satisfied, the half value width of the X-ray diffraction peak intensity of {111} plane is coated tool have been proposed less than 1 degree.

Japanese Patent Laying-Open No. 2015-163423 Japanese Patent Laying-Open No. 2015-163424 International Publication No. 2015/135802

In recent years, there has been a strong demand for energy saving and energy saving in cutting, and along with this, cutting tends to be faster and more efficient, and the coated tool has even more chipping resistance, chipping resistance, Abnormal damage resistance such as peel resistance is required, and excellent wear resistance is required over a long period of use.
However, the coated tools proposed in Patent Documents 1 to 3 are accompanied by high heat generation of alloy steel and the like, and in ultra high-speed intermittent cutting where an impact load is applied to the cutting edge, Abrasion is not yet sufficient, and it cannot be said that satisfactory cutting performance is provided over a long period of use. In addition, the cutting speed of the ultra-high-speed intermittent cutting in this specification refers to a speed twice or more the normal cutting speed.

  Therefore, the present invention solves the above-described problems, and provides a coated tool that exhibits excellent chipping resistance, particularly wear resistance, over a long period of use, even when subjected to ultra-high-speed intermittent cutting of alloy steel or the like. The purpose is to provide.

The present inventors have disclosed a composite nitride or composite carbonitride (hereinafter referred to as “TiAlCN” or “(Ti _1-x Al _x ) (C _y N _1-y )”) layer of Ti and Al. As a result of diligent research to improve the chipping resistance, particularly wear resistance, of a coated tool provided with a hard coating layer containing at least a hard coating layer on the surface of the tool substrate, the following knowledge was obtained.

The TiAlCN crystal grains that make up the TiAlCN layer have high toughness in ultra-high-speed interrupted cutting of alloy steel, etc., but they do not have sufficient hardness, so both the chipping resistance and wear resistance are sufficient. In order to obtain a tool in combination, it is desired to improve the hardness of the TiAlCN layer, that is, the wear resistance.
Therefore, the present inventors, in TiAlCN crystal grains constituting the TiAlCN layer, containing at least one of a predetermined amount of Si and B, the hardness is improved,
Furthermore, when intensive studies were made on the lattice strain in each crystal lattice of the crystal grains containing at least one of the predetermined amount of Si and B, the crystal grains containing a NaCl-type face-centered cubic structure were contained, and When X-ray diffraction is performed on crystal grains having a NaCl-type face-centered cubic structure, and the plane spacing between the (111) plane and the (200) plane is calculated as d (111) and d (200), When the absolute value ΔA of the difference between the lattice constants A (111) and A (200) calculated from d (111) and d (200) is within the range of 0.007 to 0.050 mm, It has been found that a TiAlCN layer containing a predetermined amount of at least one of Si and B further improves the wear resistance without impairing the chipping resistance.
That is, when Me represents at least one of Si and B, a TiAlCN layer that is a composite nitride or carbonitride containing a predetermined amount Me, that is, a NaCl-type face-centered cubic structure of a TiAlMeCN layer. When the ΔA measured with respect to the crystal grains possessed is 0.007 to 0.050 mm, both excellent chipping resistance and wear resistance characteristics are obtained over a long period of time in ultra-high-speed intermittent cutting of alloy steel and the like. He found out that he would have both.

The present invention has been made based on the above findings,
“(1) Surface-coated cutting in which a hard coating layer is provided on the surface of a tool base made of any of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh-pressure sintered body In the tool
(A) The hard coating layer is a composite nitride or composite carbonitride layer of Ti, Al, and Me (where Me is at least one of Si and B) having an average layer thickness of 1.0 to 20.0 μm. Containing at least the composite nitride or composite carbonitride,
Composition formula: (Ti _1-xy Al _x Me _y ) (C _z N _1-z )
The content ratio x of the total content of Ti, Al and Me in Al, the content ratio y of the total content of Ti, Al, and Me in Me, and the content of C in the total content of C and N The ratio z (where x, y, and z are atomic ratios) are 0.60 ≦ x <0.95, 0.005 ≦ y ≦ 0.100, 0.60 <x + y ≦ 0.95, respectively. 0.0000 ≦ z ≦ 0.0050 is satisfied,
(B) The average content ratio s of Cl (where s is an atomic ratio) in the total amount of atoms constituting the composite nitride or composite carbonitride satisfies 0.0001 ≦ s ≦ 0.0040,
(C) With respect to the composite nitride or composite carbonitride layer, (111) crystal grains having a NaCl-type face-centered cubic structure in the composite nitride or composite carbonitride layer measured using an X-ray diffractometer. ) Surface and (200) surface X-ray diffraction spectra, respectively, to calculate the values of the surface spacing d (111) and d (200), from the calculated d (111) and d (200) values,
A (111) = 3 ^1/2 d (111),
A (200) = 2d (200)
When A (111) and A (200) defined by the above are calculated, and the absolute value ΔA = | A (111) −A (200) | of the difference between A (111) and A (200) is obtained,
A surface-coated cutting tool characterized in that ΔA satisfies 0.007 to 0.050 mm.
(2) When the composite nitride or composite carbonitride layer is observed from the longitudinal cross-sectional direction, the average grain of individual crystal grains having a NaCl-type face-centered cubic structure in the composite nitride or composite carbonitride layer The surface-coated cutting tool according to (1) above, having a columnar structure having a width W of 0.10 to 2.00 μm and an average aspect ratio A of 2.0 to 10.0.
(3) Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride oxide layer between the tool base and the composite nitride or composite carbonitride layer of Ti, Al, and Me (1) or (2), wherein there is a lower layer comprising a Ti compound layer consisting of one or more of the above and having a total average layer thickness of 0.1 to 20.0 μm Surface coated cutting tool.
(4) The upper layer including at least an aluminum oxide layer is present at a total average layer thickness of 1.0 to 25.0 μm above the composite nitride or composite carbonitride layer. (3) The surface-coated cutting tool according to any one of the above. "
It is.

The present invention provides a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool base, and includes at least a TiAlMeCN layer having an average layer thickness of 1.0 to 20.0 μm as the hard coating layer. When expressed by the formula: (Ti _1-xy Al _x Me _y ) (C _z N _1-z ), the content ratio x in the total amount of Ti, Al and Me in Al, Me Ti, Al and Me The content ratio y occupying the total amount of C, the content ratio z occupying the total amount of C and N of C, and the average content ratio s of Cl (wherein x, y, z and s are all atomic ratios), 0.60 ≦ x <0.95, 0.005 ≦ y ≦ 0.100, 0.60 <x + y ≦ 0.95, 0.0000 ≦ z ≦ 0.0050, 0.0001 ≦ s ≦ 0.0040 In addition, the TiAlMeCN layer NaCl type X-ray diffraction is performed on the crystal grains having the face-centered cubic structure, and the interplanar spacings d (111) and d (200) between the (111) plane and the (200) plane are calculated. When (200) is calculated and the absolute value ΔA of the difference between A (111) and A (200) is obtained, ΔA satisfies 0.007Å ≦ ΔA ≦ 0.050Å.
Therefore, in the surface-coated cutting tool of the present invention, since the TiAlMeCN layer containing Me has an appropriate lattice strain (0.007Å ≦ ΔA ≦ 0.050Å) and high hardness is achieved, high heat generation such as alloy steel is generated. In addition, the TiAlMeCN layer has excellent chipping resistance and exhibits excellent wear resistance over a long period of use when subjected to ultra-high-speed intermittent cutting where an impact load acts on the cutting edge. .

  The present invention will be described in detail below.

Average thickness of the TiAlMeCN layer:
The hard coating layer of the present invention includes at least a TiAlMeCN layer represented by a composition formula: (Ti _1-xy Al _x Me _y ) (C _z N _1-z ) (where Me is at least of Si and B) One). This TiAlMeCN layer is high in hardness and has excellent wear resistance, but the effect is particularly remarkable when the average layer thickness is 1.0 to 20.0 μm. This is because when the average layer thickness is less than 1.0 μm, the layer thickness is too thin to ensure sufficient wear resistance over a long period of use, whereas when the average layer thickness exceeds 20.0 μm, TiAlMeCN This is because the crystal grains of the layer are easily coarsened and chipping is likely to occur.
Therefore, the average layer thickness was set to 1.0 to 20.0 μm.

Average composition of TiAlMeCN layer:
The TiAlMeCN layer in the present invention is
The content of Al in the total amount of Ti, Al and Me (hereinafter referred to as the “average content ratio of Al”) x,
The content of Me in the total amount of Ti, Al and Me (hereinafter referred to as “the average content of Me”) y,
The average content ratio (hereinafter referred to as “average content ratio of C”) z of the total amount of C and C in C is:
0.60 ≦ x <0.95, 0.005 ≦ y ≦ 0.100, 0.60 <x + y ≦ 0.95, 0.0000 ≦ z ≦ 0.0050 (where x, y, and z are Both are determined so as to satisfy the atomic ratio).
The reason is that if the average Al content ratio x is less than 0.60, the TiAlMeCN layer is inferior in hardness, so that the wear resistance is not sufficient when subjected to ultra-high-speed intermittent cutting of alloy steel or the like.
When the average content ratio y of Me is less than 0.005, the improvement of hardness, which is an effect of adding Me, is not sufficiently exhibited, and when it exceeds 0.10, segregation of Me to the grain boundary occurs. , The toughness is lowered and the chipping resistance is impaired.
Furthermore, it is clear that the sum of the average content ratio x of Al and the average content ratio y of Me exceeds 0.60, and if it exceeds 0.95, the content ratio of Ti is relatively reduced. , Resulting in embrittlement and reduced chipping resistance.
Therefore, the average content ratio x of Al and the average content ratio of Me were determined as 0.60 ≦ x <0.95, 0.005 ≦ y ≦ 0.100, and 0.60 <x + y ≦ 0.95.
In addition, when the average content ratio z of C contained in the TiAlMeCN layer is a minute amount in the range of 0.0000 ≦ z ≦ 0.0050, the adhesion between the TiAlMeCN layer and the tool substrate or the lower layer is improved, and By improving lubricity, the impact during cutting is relieved, and as a result, the chipping resistance and fracture resistance of the TiAlMeCN layer are improved. On the other hand, when the average content ratio z of C deviates from the range of 0.0000 ≦ z ≦ 0.0050, the toughness of the TiAlMeCN layer is lowered, and chipping resistance and chipping resistance are adversely lowered.
Therefore, the average content ratio z of C was determined to be 0.0000 ≦ z ≦ 0.0050.
Further, when the average content ratio s (where s is an atomic ratio) of Cl contained in the TiAlMeCN layer is in the range of 0.0001 ≦ s ≦ 0.0040, the lubricity is improved without reducing the toughness of the layer. be able to. That is, if the average chlorine content is less than 0.0001, the effect of improving lubricity is small. On the other hand, if the average chlorine content exceeds 0.0040, chipping resistance is lowered, which is not preferable.
Therefore, the average Cl content is defined as 0.0001 ≦ s ≦ 0.0040.

Index of lattice strain of TiAlMeCN crystal grains having a NaCl-type face-centered cubic structure (hereinafter, also simply referred to as “cubic crystal”) constituting the TiAlMeCN layer:
In the present invention, in addition to lattice strain, which is an improvement in hardness by adding Me, in the cubic TiAlMeCN crystal grains of the TiAlMeCN layer, in addition to lattice strain by controlling film formation conditions, a hard strain of the TiAlCN layer is introduced. Improve.
The introduction of the lattice strain by controlling the film forming conditions can be performed by, for example, a thermal CVD method using NH ₃ when forming the TiAlMeCN layer.
Specifically, it is as follows.
The chemical vapor deposition apparatus to be used includes a gas group A composed of NH ₃ and H ₂ , TiCl ₄ , AlCl ₃ , N ₂ , Al (CH ₃ ) ₃ , H _2, and at least one of SiCl ₄ and BCl ₃ (hereinafter, The gas group B consisting of “MeCl _x ”) is supplied into the reactor from the separate gas supply pipes, and the supply of the gas group A and the gas group B into the reactor is, for example, constant. The gas is supplied so that the gas flows for a time shorter than that period, and the gas supply of the gas group A and the gas group B has a phase difference shorter than the gas supply time. A reaction gas is supplied to the surface of the tool base, and the supply ratio N ₂ / (AlCl ₃ + Al (CH ₃ ) ₃ ) is relatively large for N ₂ , AlCl ₃ , and Al (CH ₃ ) ₃ that are gas components. Each to be By chemical vapor deposition to adjust the supply amount of the scan component, it is possible to form a TiAlMeCN layer predetermined lattice strain is introduced.
In addition, as the supply ratio N ₂ / (AlCl ₃ + Al (CH ₃ ) ₃ ) increases, ΔA tends to increase generally.

Here, specific conditions for the chemical vapor deposition are as follows as an example.
Reaction gas composition (volume% with respect to the total of gas group A and gas group B):
Gas group A: NH ₃ : 2.0 to 6.0%, H ₂ : 65 to 75%,
Gas group B: AlCl ₃ : 0.50 to 0.90%, TiCl ₄ : 0.2 to 0.3%, MeCl _x : 0.10 to 0.20%, N ₂ : 3.0 to 12.0 _{%, Al (CH 3) 3} : 0.00~0.10%, H 2: remainder,
_{N 2 / (AlCl 3 + Al} (CH 3) 3): 3.0~24.0
Reaction atmosphere pressure: 4.5 to 5.0 kPa,
Reaction atmosphere temperature: 700 to 900 ° C.
Supply cycle: 6.0-9.0 seconds,
Gas supply time per cycle: 0.15 to 0.25 seconds,
Phase difference in supply of gas group A and gas group B: 0.10 to 0.20 seconds

The lattice strain of cubic crystal grains in the TiAlMeCN layer formed as described above can be measured by the following method, and the lattice strain index ΔA can be obtained as follows.
First, X-ray diffraction is performed on the TiAlMeCN layer, and X-ray diffraction spectra for the (111) plane and the (200) plane of the TiAlMeCN crystal grains are obtained.
Next, from the X-ray diffraction spectra measured for the (111) plane and the (200) plane, Bragg's formula: 2 d sin θ = nλ (where d is the lattice spacing, θ is the Bragg angle, 2θ is the diffraction angle, and λ is incident. Using the X-ray wavelength, n is an integer, the lattice spacings d (111) and d (200) between the (111) plane and the (200) plane are calculated.
A (111) and A (200) are then
A (111) = 3 ^1/2 d (111),
A (200) = 2d (200),
And the values of A (111) and A (200) are obtained from the values of d (111) and d (200) calculated above.
The lattice strain index ΔA is the absolute value of the difference between A (111) and A (200), that is,
ΔA = | A (111) −A (200) |
Can be obtained as
When ΔA satisfies 0.007Å ≦ ΔA ≦ 0.050Å, the TiAlMeCN layer comes to have a high hardness. As a result, high heat generation occurs and an impact load is applied to the cutting edge. Even when subjected to ultra high-speed intermittent cutting that acts, it exhibits excellent wear resistance.

  The TiAlMeCN layer having the lattice strain index ΔA defined above exhibits high hardness due to the presence of lattice strain in the layer by controlling the film formation conditions in addition to lattice strain, which is an improvement in hardness due to the addition of Me, As a result, excellent wear resistance is exhibited. However, if ΔA is less than 0.007 mm, the lattice strain is small, so the effect of improving the hardness is not sufficient. On the other hand, if ΔA exceeds 0.050 mm, the lattice strain becomes excessive. Therefore, since the chipping resistance at the time of cutting is lowered, the ΔA is set in the range of 0.007Å ≦ ΔA ≦ 0.050Å.

Crystal structure:
As described above, the present invention is the interplanar spacing of the (111) plane and the (200) plane obtained by performing X-ray diffraction on the crystal grains having the NaCl-type face-centered cubic structure constituting the TiAlMeCN layer. , By adjusting the absolute value ΔA of the difference between the lattice constants A (111) and A (200) calculated from d (111) and d (200) to a predetermined range, the hardness of the TiAlCN layer is increased. The present inventors have found that a coated tool excellent in both chipping resistance and wear resistance can be obtained by improving the wear resistance and applying this to a tool.
In particular, when the TiAlMeCN layer is observed from the longitudinal cross-sectional direction, the average grain width W of each crystal grain having a NaCl-type face-centered cubic structure in the composite nitride or composite carbonitride layer is 0.10 to 2 When it has a columnar structure with an average aspect ratio A of 2.0 to 10.0, the hardness and toughness of the crystal grains are improved, combined with the effect of the TiAlCN layer as a hard coating layer. Thus, even more excellent characteristics can be exhibited.
That is, by setting the average particle width W to 0.10 μm or more and 2.00 μm or less, the reactivity with the work material is reduced, the wear resistance is exhibited, the toughness is improved, and the chipping resistance is improved. It can be improved further.
Therefore, the average particle width W is more preferably 0.10 to 2.00 μm.
In addition, by having an average aspect ratio A of 2.0 or more and 10.0 or less and having a sufficient columnar structure, it is difficult for small equiaxed crystals to fall off, and sufficient wear resistance can be exhibited. If it is 10.0 or less, since the strength of the crystal grains is increased, the chipping resistance is further improved.
Therefore, the average aspect ratio A is more preferably 2.0 to 10.0.
In the present invention, the average aspect ratio A refers to the surface of the tool base when the longitudinal section of the hard coating layer is observed in a range including a width of 100 μm and a height including the entire hard coating layer using a scanning electron microscope. Observed from the cross section side (longitudinal section) of the vertical coating layer, the particle width w in the direction parallel to the substrate surface and the particle length l in the direction perpendicular to the substrate surface are measured, and the aspect ratio a (= l / W), the average value of the aspect ratio a obtained for each crystal grain is calculated as the average aspect ratio A, and the average value of the grain width w obtained for each crystal grain is the average grain width W Calculate as

Lower layer and upper layer:
In the present invention, by providing the TiAlMeCN layer as the hard coating layer, it has sufficient chipping resistance and wear resistance, but Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride oxide A lower layer comprising a Ti compound layer comprising one or more of the layers and having a total average layer thickness of 0.1 to 20.0 μm, and / or an upper portion comprising at least an aluminum oxide layer When the layers are provided with a total average layer thickness of 1.0 to 25.0 μm, combined with the effect produced by these layers, it is possible to exhibit further excellent characteristics.
Ti consisting of one or more of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride layer, and having a total average layer thickness of 0.1 to 20.0 μm When a lower layer including a compound layer is provided, if the total average layer thickness of the lower layer is less than 0.1 μm, the effect of the lower layer is not sufficiently achieved. On the other hand, if it exceeds 20.0 μm, the crystal grains are likely to be coarsened. , Chipping is likely to occur. Further, if the total average layer thickness of the upper layer including the aluminum oxide layer is less than 1.0 μm, the effect of the upper layer is not sufficiently achieved. On the other hand, if it exceeds 25.0 μm, the crystal grains are likely to be coarsened and chipping is caused. It tends to occur.

Next, the coated tool of the present invention will be specifically described with reference to examples.
In the following examples, the case where a WC-based cemented carbide or TiCN-based cermet is used as the tool substrate will be described. However, the same applies when a cBN-based ultrahigh pressure sintered body is used as the tool substrate.

<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 diameter of 0.1 to 3 μm were prepared. These raw material powders are shown in Table 1. Then, after adding wax, ball mill mixing in acetone for 24 hours, drying under reduced pressure, press-molding into a green compact of a predetermined shape at a pressure of 98 MPa, and this green compact in a vacuum of 5 Pa 1 to 370 to 1470 ° C. at a predetermined temperature held for 1 hour under vacuum sintering. After sintering, tool bases A to C made of WC-base cemented carbide having ISO standard SEEN1203AFSN insert shape are used. Each was manufactured.

In addition, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, WC powder, Co powder, all having an average particle diameter of 0.1 to 2 μm. And Ni powder are prepared, these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and then pressed into a 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, and after sintering, a tool base D made of TiCN-based cermet having an ISO standard SEEN1203AFSN insert shape was produced.

Next, a TiAlMeCN layer was formed on the surfaces of these tool bases A to D by CVD using a CVD apparatus.
The CVD conditions are as follows.
Formation conditions A to J shown in Tables 4 and 5, that is, from a gas group A composed of NH ₃ and H ₂ , TiCl ₄ , AlCl ₃ , MeCl _x , Al (CH ₃ ) ₃ , N ₂ , H ₂ As a gas group B and a gas supply method, the reaction gas composition (capacity% with respect to the total of the gas group A and the gas group B) is set as the gas group A, NH ₃ : 2.0 to 6.0%. , H ₂ : 65 to 75%, AlCl ₃ : 0.50 to 0.90% as gas group B, TiCl ₄ : 0.2 to 0.3%, MeCl _x : 0.10 to 0.20%, N ₂ : 3.0 to 12.0%, Al (CH ₃ ) ₃ : 0.00 to 0.10%, H ₂ : remaining, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 700 to 900 ° C., supply cycle 6.0 to 9.0 seconds, gas supply time per cycle 0. 5 to 0.25 seconds, the phase difference between the gas supply group A and the gas group B and 0.10 to 0.20 seconds, _{also, N 2, AlCl 3, Al} (CH 3) 3 of feed ratio _N 2 / ( Vapor deposition was performed by a thermal CVD method with AlCl ₃ + Al (CH ₃ ) ₃ ) of 3.0 to 24.0 for a predetermined time.
By forming the TiAlMeCN layer under the above-mentioned conditions, the average layer thickness, the average Al content ratio x, the Me average content ratio y, the C average content ratio z, and the Cl average content ratio s shown in Table 7 are formed. Invention coated tools 1-15 were produced.
In addition, about this invention coated tools 4-11, the lower layer shown in Table 6 and / or the upper layer were formed on the formation conditions shown in Table 3.

For the purpose of comparison, the average layer thickness (μm) shown in Table 8 is obtained by performing chemical vapor deposition on the surfaces of the tool bases A to D under the formation conditions A ′ to H ′ shown in Tables 4 and 5. Comparative coating tools 1 to 15 were manufactured by vapor-depositing at least a TiAlMeCN layer or a hard coating layer containing TiAlCN.
In addition, similarly to this invention coated tools 4-11, about the comparative coated tools 4-11, the lower layer and / or the upper layer which were shown in Table 6 on the formation conditions shown in Table 3 were formed.

  Moreover, the cross section (longitudinal section) in the direction perpendicular to the tool base of each constituent layer of the present invention coated tools 1 to 15 and comparative coated tools 1 to 15 is measured using a scanning electron microscope (5000 times magnification), When the average layer thickness was obtained by measuring and averaging the five layer thicknesses in the observation field, all were the average layer thicknesses shown in Table 7 and Table 8.

Furthermore, the average Al content x, the average Me content y, and the average Cl content s of the TiAlMeCN layer and TiAlCN layer (y is less than 0.0001) are measured with an electron beam microanalyzer (Electron-Probe-). In a sample whose surface was polished using Micro-Analyzer (EPMA), an electron beam was irradiated from the sample surface side, and an average content ratio of Al, Me, and Cl x from an average of 10 points in the analysis result of the obtained characteristic X-ray x , Y and s were determined.
About the average content rate z of C, it calculated | required by secondary ion mass spectrometry (Secondary-Ion-Mass-Spectroscopy: SIMS). The ion beam was irradiated in the 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 content ratio z of C shows the average value of the depth direction about a TiAlMeCN layer or a TiAlCN layer.
However, the content ratio of C excludes the inevitable content ratio of C that is included without intentionally using a gas containing C as a gas raw material.
Tables 7 and 8 show the values of x, y, z, and s obtained above (all of x, y, z, and s are atomic ratios).

In addition, X-ray diffraction is performed from the direction perpendicular to the longitudinal section of the TiAlMeCN layer or the TiAlCN layer, and Bragg's formula is obtained from the X-ray diffraction spectra of the (111) plane and (200) plane of the cubic crystal grains: Based on 2 d sin θ = nλ, the respective lattice spacings d (111) and d (200) were calculated.
Here, from the above d (111) and d (200), A (111) and A (200) corresponding to the lattice constant were calculated from the following equations.
A (111) = 3 ^1/2 d (111),
A (200) = 2d (200),
Next, the absolute value of the difference between A (111) and A (200) was determined as a lattice strain index ΔA.
Tables 7 and 8 show the values of d (111), d (200), A (111), A (200) and ΔA determined above.
X-ray diffraction is measured under the following measurement conditions: Cu-Kα ray (λ = 1.5418Å) as a source, measurement range (2θ): 30 to 50 degrees, scan step: 0.013 degrees, measurement time per step : Measurement was performed under the condition of 0.48 sec / step.

Moreover, about this invention coated tool 1-15 and comparative coated tool 1-15, it uses a scanning electron microscope (magnification 5000 times and 20000 times) from the cross-sectional direction of the direction perpendicular | vertical to a tool base | substrate, and a tool base | substrate surface and horizontal direction present in the range of length 100μm in the composite nitride or composite carbonitride layer _{(Ti 1-x-y Al} x Me y) (C z N 1-z) of NaCl type in the layer face centered cubic Each crystal grain having a structure is observed from the side of the coating cross section perpendicular to the tool substrate surface, and the particle width w in the direction parallel to the substrate surface and the particle length l in the direction perpendicular to the substrate surface are measured. The aspect ratio a (= l / w) of the grains is calculated, the average value of the aspect ratio a obtained for each crystal grain is calculated as the average aspect ratio A, and the grain width w obtained for each crystal grain Average value It was calculated as the average particle width W. Tables 7 and 8 show the values of W and A determined above.

  Next, the present coated tools 1 to 15 and comparative coated tools 1 to 15 are described below in a state where each of the various coated tools is clamped to a tool steel cutter tip portion having a cutter diameter of 125 mm by a fixing jig. The dry high-speed face milling, which is a kind of ultra-high-speed intermittent cutting of alloy steel, and a center-cut cutting test were performed, and the flank wear width of the cutting blade was measured.

Tool substrate: WC-based cemented carbide, TiCN-based cermet,
Cutting test: dry high-speed face milling, center cutting,
Work material: Block material of JIS / SCM415 width 100mm, length 400mm,
Rotational speed: 1146 min ⁻¹
Cutting speed: 450 m / min,
Incision: 1.5mm,
Single blade feed: 0.1 mm / tooth,
Cutting time: 8 minutes
(Normal cutting speed: 200 m / min)
Table 9 shows the results.

<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 each having an average particle diameter of 0.1 to 3 μm are prepared. Was added to the blending composition shown in Table 10, added with wax, mixed in a ball mill in acetone for 24 hours, dried under reduced pressure, and press-molded into a compact of a predetermined shape at a pressure of 98 MPa. By subjecting the body to vacuum sintering at a predetermined temperature in the range of 1370 to 1470 ° C. for 1 hour in a vacuum of 5 Pa, and after sintering, the cutting edge is subjected to a honing process of R: 0.07 mm Tool bases α to γ made of a WC-base cemented carbide having an insert shape of ISO standard CNMG120212 were manufactured.

  Moreover, as raw material powders, TiCN (TiC / TiN = 50/50 in mass ratio) powder, NbC powder, WC powder, Co powder, and Ni powder each having an average particle diameter of 0.1 to 2 μm are prepared, These raw material powders were blended into the composition shown in Table 11, wet mixed with a ball mill for 24 hours, dried, and then pressed into a green compact at a pressure of 98 MPa. Sintered in an atmosphere at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge part is subjected to a honing process of R: 0.09 mm so that the TiCN base has an insert shape of ISO standard / CNMG120212 A cermet tool substrate δ was formed.

Next, on the surfaces of the tool base α to γ and the tool base δ, using a chemical vapor deposition apparatus, formation conditions A to J shown in Tables 4 and 5, that is, a gas group A composed of NH ₃ and H ₂ are used. And a gas group B composed of TiCl ₄ , AlCl ₃ , MeCl _x , N ₂ , H ₂ , and a method of supplying each gas, the reaction gas composition (capacity% relative to the total of the gas group A and the gas group B) the, _NH 3 as a gas group _{a: 2.0~6.0%, H 2:} 65~75%, AlCl 3 as gas group _{B: 0.50~0.90%, TiCl 4:} 0.2~0 .3%, MeCl _x : 0.10 to 0.20%, N ₂ : 3.0 to 12.0%, Al (CH ₃ ) ₃ : 0.0 to 0.1%, H ₂ : residue, reaction Atmospheric pressure: 4.5 to 5.0 kPa, reaction ambient temperature: 700 to 900 ° C., supply cycle .0～9.0 seconds, the gas supply time per one period 0.15-0.25 second, a phase difference 0.10 to 0.20 seconds of the gas group A and the gas group B, _also, N 2, AlCl _3, Al a _{(CH 3) 3} feed ratio of _{N 2 / (AlCl 3 + Al} (CH 3) 3) as a 3.0 to 24.0, a predetermined time, was vapor deposited by the thermal CVD method.
By forming the TiAlMeCN layer under the above-described conditions, the average layer thickness, the average Al content ratio x, the average Me content ratio y, the average C content ratio z, and the average Cl content ratio s shown in Table 13 are shown. Invention coated tools 16-30 were produced.
In addition, about this invention coated tools 19-26, the lower layer and / or the upper layer which were shown in Table 12 on the formation conditions shown in Table 3 were formed.

For comparison purposes, the CVD apparatus was also used on the surfaces of the tool bases α to γ and the tool base δ, and the formation conditions A ′ to H ′ shown in Tables 4 and 5 and the average layer thicknesses shown in Table 14 were used. Comparative coating tools 16 to 30 shown in Table 14 were produced by vapor-depositing a hard coating layer in the same manner as the coating tool of the present invention.
In addition, similarly to this invention coating tool 19-26, about the comparison coating tool 19-26, the lower layer and / or upper layer which were shown in Table 12 were formed on the formation conditions shown in Table 3.

  The cross-section of each constituent layer of the inventive coated tool 16-30 and comparative coated tool 16-30 is measured using a scanning electron microscope (5000 times magnification), and the layer thicknesses at five points in the observation field are measured and averaged. When the average layer thickness was determined, the average layer thicknesses shown in Table 13 and Table 14 were all shown.

Moreover, about the TiAlMeCN layer and TiAlCN layer of the present invention coated tools 16 to 30 and comparative coated tools 16 to 30, using the same method as that shown in Example 1, x, y, z, s, d ( 111), d (200), A (111), A (200), ΔA, average grain width W and average aspect ratio A of the crystal grains.
Tables 13 and 14 show the results.

Next, in the state where all the various coated tools are screwed to the tip of the tool steel tool with a fixing jig, the present coated tools 16 to 30 and comparative coated tools 16 to 30 are shown below. We conducted wet ultra-high-speed intermittent cutting tests on carbon steel and cast iron, and measured the flank wear width of the cutting blades.
Cutting condition 1:
Work material: JIS-S35C lengthwise equal length 4 round fluted round bars,
Cutting speed: 450 m / min,
Cutting depth: 1.0 mm,
Feed: 0.15mm / rev,
Cutting time: 5 minutes,
(Normal cutting speed is 220 m / min),
Cutting condition 2:
Work material: JIS / FCD450 lengthwise equidistant round bars with 4 vertical grooves,
Cutting speed: 400 m / min,
Cutting depth: 1.0 mm,
Feed: 0.20 mm / rev,
Cutting time: 5 minutes,
(Normal cutting speed is 180 m / min),
Table 15 shows the results of the cutting test.

  From the results shown in Table 9 and Table 15, in the coated tool of the present invention, the cubic crystal grains of the TiAlMeCN layer have a predetermined Al content rate, Me content rate, C content rate, Cl content rate, and Since the lattice strain satisfying 0.007Å ≦ ΔA ≦ 0.050Å is formed, the hardness is high, and as a result, it is accompanied by high heat generation and the cutting blade is subjected to intermittent / impact high loads. Even when used for high-speed intermittent cutting, it exhibits excellent wear resistance over a long period of use without the occurrence of chipping or chipping.

  On the other hand, the cubic crystal grains constituting the TiAlMeCN layer and the TiAlCN layer satisfy a predetermined Al content rate, Me content rate, C content rate, Cl content rate, 0.007Å ≦ ΔA ≦ 0.050Å. It is clear that the comparative coated tool in which no lattice strain is formed reaches the end of its life in a short time due to the occurrence of abnormal damage such as chipping or the progress of wear in ultra high-speed intermittent cutting.

  As described above, the coated tool of the present invention can be used not only for ultra high-speed intermittent cutting of alloy steel but also as a coated tool for various work materials, and also exhibits excellent cutting performance over a long period of use. Therefore, it is possible to sufficiently satisfy the high performance of the cutting device, the labor saving and energy saving of the cutting work, and the cost reduction.

Claims (4)

In a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool base composed of any of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh-pressure sintered body,
(A) The hard coating layer is a composite nitride or composite carbonitride layer of Ti, Al, and Me (where Me is at least one of Si and B) having an average layer thickness of 1.0 to 20.0 μm. Containing at least the composite nitride or composite carbonitride,
Composition formula: (Ti _1-xy Al _x Me _y ) (C _z N _1-z )
The content ratio x of the total content of Ti, Al and Me in Al, the content ratio y of the total content of Ti, Al, and Me in Me, and the content of C in the total content of C and N The ratio z (where x, y, and z are atomic ratios) are 0.60 ≦ x <0.95, 0.005 ≦ y ≦ 0.100, 0.60 <x + y ≦ 0.95, respectively. 0.0000 ≦ z ≦ 0.0050 is satisfied,
(B) The average content ratio s of Cl (where s is an atomic ratio) in the total amount of atoms constituting the composite nitride or composite carbonitride satisfies 0.0001 ≦ s ≦ 0.0040,
(C) With respect to the composite nitride or composite carbonitride layer, (111) crystal grains having a NaCl-type face-centered cubic structure in the composite nitride or composite carbonitride layer measured using an X-ray diffractometer. ) Surface and (200) surface X-ray diffraction spectra, respectively, to calculate the values of the surface spacing d (111) and d (200), from the calculated d (111) and d (200) values,
A (111) = 3 ^1/2 d (111),
A (200) = 2d (200)
When A (111) and A (200) defined by the above are calculated, and the absolute value ΔA = | A (111) −A (200) | of the difference between A (111) and A (200) is obtained,
A surface-coated cutting tool characterized in that ΔA satisfies 0.007 to 0.050 mm.   The composite nitride or composite carbonitride layer has an average grain width W of individual grains having a NaCl-type face-centered cubic structure in the composite nitride or composite carbonitride layer when observed from the longitudinal cross-sectional direction. The surface-coated cutting tool according to claim 1, wherein the surface-coated cutting tool has a columnar structure having an average aspect ratio A of 2.0 to 10.0.   Between the tool base and the Ti, Al and Me composite nitride or composite carbonitride layer, a Ti carbide layer, a nitride layer, a carbonitride layer, a carbonate layer, and a carbonitride oxide layer The surface-coated cutting tool according to claim 1 or 2, wherein there is a lower layer comprising a Ti compound layer composed of one or more layers and having a total average layer thickness of 0.1 to 20.0 µm. .   4. An upper layer including at least an aluminum oxide layer is present at a total average layer thickness of 1.0 to 25.0 [mu] m above the composite nitride or composite carbonitride layer. The surface-coated cutting tool according to any one of the above.