JP6391045B2 - A surface-coated cutting tool that exhibits excellent chipping resistance with a hard coating layer in high-speed intermittent cutting - Google Patents

Description

  The present invention is a surface-coated cutting tool that exhibits high chipping resistance with a hard coating layer, such as high-speed intermittent cutting with high heat generation such as stainless steel and an impact load acting on the cutting edge. Hereinafter, this is referred to as a coated tool).

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 2. Description of the Related Art A coated tool is known in which a Ti—Al-based composite nitride layer is formed as a hard coating layer on a surface of a substrate (hereinafter collectively referred to as a substrate) by physical vapor deposition. Such a coated tool is known to exhibit excellent wear resistance, and is being used for various purposes such as a machining center and a multi-task machine.
However, the conventional coated tool formed by coating a Ti-Al based composite nitride layer has relatively high wear resistance, but it tends to cause abnormal wear such as chipping when used under high-speed interrupted cutting conditions. Therefore, various proposals for improving the hard coating layer have been made.

For example, Patent Document 1 discloses a composite nitride of Al and Ti that satisfies the composition formula (Al _1-X Ti _X ) N (wherein X is 0.40 to 0.60 in atomic ratio) on the substrate surface. When the crystal orientation analysis is performed on the composite nitride layer using an electron beam backscattering diffractometer, the crystal orientation {111} is within a range of 0 to 15 degrees from the normal direction of the surface polished surface. A crystal arrangement in which the area ratio of crystal grains is 50% or more, and the ratio of small-angle grain boundaries (0 <θ ≦ 15 °) is 50% or more when the angle between adjacent crystal grains is measured It is disclosed that a coated tool exhibiting excellent fracture resistance can be obtained by high-speed heavy cutting by depositing a hard coating layer composed of a modified (Al, Ti) N layer showing Yes.

  Further, in Patent Document 2, in an end mill coated with a composite nitride, carbonitride, and carbide of Ti and Al, the diffraction intensity of the {111} plane in the X-ray diffraction of the hard coating layer is I (111), {200 } When the diffraction intensity of the surface is I (200), the value of I (200) / I (111) is 2.0 or less, so that cutting of high hardness steel exceeding Rockwell hardness 50 (C scale) Discloses a coated tool with improved adhesion and wear resistance of a hard coating layer.

However, since the coated tools disclosed in Patent Documents 1 and 2 described above have a hard coating layer formed by physical vapor deposition, the Al content ratio X cannot be increased to 0.6 or more, and cutting is further performed. It is desired to improve performance.
From such a viewpoint, a technique for increasing the Al content ratio X to about 0.9 by forming a hard coating layer by chemical vapor deposition has also been proposed.

For example, Patent Document 3 discloses that the value of the Al content ratio X is 0.65 by performing chemical vapor deposition in a temperature range of 650 to 900 ° C. in a mixed reaction gas of TiCl ₄ , AlCl ₃ , and NH _3. Although it is described that a (Ti _1-X Al _X ) N layer having a thickness of 0.95 can be formed, this document further describes an Al ₂ O ₃ layer on the (Ti _1-X Al _X ) N layer. Therefore, the cutting performance is improved by forming the (Ti _1-X Al _X ) N layer in which the value of X is increased from 0.65 to 0.95. It has not been elucidated what kind of influence it has.

Further, in Patent Document 4, the upper layer is made of Ti _1-x Al _x N, Ti _1-x Al _x C, and / or Ti _1-x Al _x CN, and 0.65 ≦ x ≦ 0. 9, preferably 0.7 ≦ x ≦ 0.9, and the upper layer has a compressive stress between 100 and 1100 MPa, preferably between 400 and 800 MPa, and the TiCN layer or Al ₂ O ₃ layer is the upper layer It is disclosed that a coated tool in which a hard coating layer disposed under the layer is formed by chemical vapor deposition has excellent heat resistance and cycle fatigue strength.

JP 2008-264890 A Japanese Patent Laid-Open No. 9-291353 Special table 2011-516722 gazette Special table 2011-513594 gazette

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 peeling resistance is required, and excellent wear resistance is required over a long period of use.
However, in the coating tools described in Patent Documents 1 and 2 described above, a hard coating layer made of a (Ti _1-X Al _X ) N layer is formed by physical vapor deposition, and the Al content X in the film is increased. Therefore, for example, when the alloy steel is subjected to high-speed intermittent cutting, there is a problem that the chipping resistance is not sufficient.

On the other hand, with respect to the (Ti _1-X Al _X ) N layer formed by the chemical vapor deposition method described in Patent Documents 3 and 4 described above, the Al content X can be increased and a cubic structure is formed. Although a hard coating layer having a predetermined hardness and excellent wear resistance can be obtained, the adhesion strength with the substrate is not sufficient and the toughness is inferior. When used as a coated tool for intermittent cutting, abnormal damage such as chipping, chipping and peeling is likely to occur, and it cannot be said that satisfactory cutting performance is exhibited.

  Therefore, the present invention provides a coated tool that exhibits excellent chipping resistance and excellent wear resistance over a long period of use even when subjected to high-speed intermittent cutting of stainless steel, etc. It is intended to do.

From the above-mentioned viewpoints, the present inventors have combined Ti and Al nitrides or carbonitrides (hereinafter sometimes referred to as “(Ti _1-X Al _X ) (C _Y N _1-Y )”). As a result of earnest research to improve the chipping resistance and wear resistance of the coated tool formed by chemical vapor deposition of the hard coating layer made of the following, the following knowledge was obtained.

For example, as a hard coating layer, trimethylaluminum (Al (CH ₃ ) ₃ ) is used as a reactive gas component on the surface of a substrate composed of either a WC-based cemented carbide, a TiCN-based cermet, or a cBN-based ultrahigh-pressure sintered body. At least a Ti-Al composite nitride or composite carbonitride layer formed by chemical vapor deposition such as thermal CVD, and the composition formula: (Ti _1-X Al _X ) (C _Y N _{1- Y} )), the average content ratio X _avg in the total amount of Ti and Al in Al and the average content ratio Y _avg in the total amount of C and N in C (where X _avg and Y _avg are both atoms) Ratio) satisfies 0.60 ≦ X _avg ≦ 0.95 and 0 ≦ Y _avg ≦ 0.005, respectively, and has a cubic structure in crystal grains constituting the composite nitride or composite carbonitride layer Exist, and the film formation conditions during the deposition are adjusted. When the hard coating layer analyzes the crystal orientation of individual crystal grains from the longitudinal cross-sectional direction of the Ti and Al composite nitride or composite carbonitride layer using an electron beam backscattering diffractometer There is a cubic crystal phase in which an electron backscatter diffraction image of the cubic crystal lattice is observed, and a normal of the {100} plane that is the crystal plane of the cubic crystal grain with respect to the normal direction of the surface of the tool base is formed. The inclination angle is measured, and the inclination angle within the range of 0 to 45 degrees with respect to the normal direction among the inclination angles is divided for each pitch of 0.25 degrees, and the frequencies existing in each division are tabulated. When the inclination angle frequency distribution is obtained, the highest peak is present in the inclination angle section within the range of 0 to 12 degrees, and the total of the frequencies existing within the range of 0 to 12 degrees is in the inclination angle number distribution. Shows a ratio of 45% or more of the total frequency, When the structure of the layer or the composite carbonitride layer is observed with a scanning electron microscope from the surface side, the individual crystal grains having a cubic structure in the composite nitride or the composite carbonitride layer are in the layer thickness direction. A polygonal facet having no angle of less than 90 degrees in a plane perpendicular to the surface, the facet being formed on one of the equivalent crystal planes represented by {100} of the crystal grain. In the plane perpendicular to the layer thickness direction, the frictional resistance between the surface of the hard coating layer and the work material is reduced, and the area ratio of 50% or more of the whole is reduced. It has been found that the lubricity is improved and the chipping resistance is improved.

  Therefore, when a coated tool having a hard coating layer as described above is used for, for example, high-speed intermittent cutting of alloy steel, the occurrence of chipping, chipping, peeling, etc. can be suppressed, and over a long period of use. Excellent wear resistance can be demonstrated.

The present invention has been made based on the research results as described above,
“(1) In a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool base composed of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh-pressure sintered body The hard coating layer includes at least a composite nitride or composite carbonitride layer of Ti and Al having an average layer thickness of 1 to 20 μm formed by a chemical vapor deposition method, and has a composition formula: (Ti _1-X Al _X ) When expressed as (C _Y N _1-Y ), the average content ratio X _avg in the total amount of Ti and Al in Al and the average content ratio Y _avg in the total amount of C and N in C (where X _avg , Y _avg is an atomic ratio) satisfying 0.60 ≦ X _avg ≦ 0.95 and 0 ≦ Y _avg ≦ 0.005, respectively.
The composite nitride or composite carbonitride layer includes at least a Ti and Al composite nitride or composite carbonitride phase having a NaCl-type face-centered cubic structure,
For the composite nitride or composite carbonitride layer, the crystal orientation of each crystal grain is analyzed from the longitudinal cross-sectional direction of the Ti and Al composite nitride or composite carbonitride layer using an electron beam backscattering diffractometer. In this case, there is a cubic crystal phase in which an electron backscatter diffraction image of the cubic crystal lattice is observed, and the normal of the {100} plane that is the crystal plane of the cubic crystal grain with respect to the normal direction of the tool base surface Measures the tilt angle formed by, and divides the tilt angle within the range of 0 to 45 degrees with respect to the normal direction among the tilt angles by pitch of 0.25 degrees, and counts the frequencies existing in each section When the inclination angle distribution is obtained, 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 the inclination angle number. Indicates a proportion of 45% or more of the total frequency in the distribution, and When the structure of the composite nitride or composite carbonitride layer is observed with a scanning electron microscope from the surface side, the individual crystal grains having a cubic structure in the composite nitride or composite carbonitride layer are A polygonal facet that does not have an angle of less than 90 degrees in a plane perpendicular to the layer thickness direction, and the facet is formed on one of the equivalent crystal planes represented by {100} of the crystal grains The surface-coated cutting tool is characterized in that the facet occupies an area ratio of 50% or more of the whole in a plane perpendicular to the layer thickness direction.
(2) The composite nitride or composite carbonitride layer is composed of a single phase of Ti and Al composite nitride or composite carbonitride having a NaCl-type face-centered cubic structure. The surface-coated cutting tool described.
(3) The composite nitride or composite carbonitride layer is composed of a mixed phase in which two or more kinds of phases coexist, and the mixed phase is a composite nitriding of Ti and Al having a NaCl type face centered cubic structure. Each of the other phases coexisting in the mixed phase includes at least one element selected from Ti and Al and at least one element selected from C and N. The surface-coated cutting tool according to (1), wherein
(4) When a crystal structure analysis by X-ray diffraction is performed on the composite nitride or composite carbonitride layer, a peak derived from a cubic structure and a peak derived from a hexagonal crystal are observed, and the { The peak intensity ratio Ic {200} / Ih {200} between the peak intensity Ic {200} due to 200} and the peak intensity Ih {200} due to {200} having a hexagonal structure is larger than 3.0 ( The surface-coated cutting tool according to 1) or (3).
(5) The composite nitride or composite carbonitride layer is composed of an upper layer having a cubic structure and a lower layer having a hexagonal structure, and the average layer thickness of the lower layer is 0.3 to 1.0 μm. The surface-coated cutting tool according to (1), (3) or (4), wherein the average grain size R of the crystal grains is 0.01 to 0.30 μm.
(6) A tool base composed of any one of the tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh-pressure sintered body, and a composite nitride or composite carbonitride of Ti and Al. Between the layers, it consists of one or more of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride layer, and a total average of 0.1 to 20 μm The surface-coated cutting tool according to any one of (1) to (5), wherein a Ti compound layer having a layer thickness exists.
(7) The upper layer including an aluminum oxide layer having an average layer thickness of at least 1 to 25 μm is present on the upper part of the composite nitride or composite carbonitride layer. (1) to (6) The surface coating cutting tool in any one.
(8) The composite nitride or composite carbonitride layer is formed by a chemical vapor deposition method containing at least trimethylaluminum as a reactive gas component. (1) to (7) The surface coating cutting tool in any one. "
It has the characteristics.

  Next, the hard coating layer of the coated tool of the present invention will be described more specifically.

Average layer thickness of composite nitride or composite carbonitride layer of Ti and Al:
In the hard coating layer of the present invention, the composite nitride or composite carbonitride layer of Ti and Al, if the average layer thickness is less than 1 μm, it is not possible to ensure sufficient wear resistance over a long period of use, On the other hand, when the average layer thickness exceeds 20 μm, it becomes easy to cause thermoplastic deformation by high-speed intermittent cutting with high heat generation, which causes uneven wear. Therefore, the average layer thickness is preferably 1 to 20 μm, more preferably 1 to 10 μm.
In addition, between a tool base made of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultra-high pressure sintered body and Ti and Al composite nitride or composite carbonitride layer The average total layer thickness of the Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride layer formed on the thin layer is less than 0.1 μm, so that it can be used over a long period of time. On the other hand, if the average layer thickness is larger than 20 μm, the adhesion strength between the tool base and the composite nitride or composite carbonitride layer of Ti and Al is lowered, and the peel resistance is lowered. Therefore, the average layer thickness is desirably 0.1 to 20 μm.
When the upper layer includes an aluminum oxide layer, if the average layer thickness of the aluminum oxide layer is less than 1 μm, the layer thickness is too thin to ensure wear resistance over a long period of use. Therefore, the average layer thickness of the aluminum oxide layer is desirably 1 to 25 μm.

Composition of Ti and Al composite nitride or composite carbonitride layer ((Ti _1-X Al _X ) (C _Y N _1-Y ) layer):
The (Ti _1-X Al _X ) (C _Y N _1-Y ) layer constituting the main layer of the hard coating layer of the present invention has an average Al content ratio X _avg (atomic ratio) of less than 0.60. When the value of X _avg (atomic ratio) exceeds 0.95, on the other hand, when the value of X _avg (atomic ratio) exceeds 0.95, (Ti _{1- X Al X) (C Y N} 1-Y) layer high-temperature strength of itself is lowered, chipping, it becomes defective likely to occur. Therefore, the value of the average content ratio X _avg (atomic ratio) of Al needs to be 0.60 or more and 0.95 or less.
Further, in the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer, the C component improves the hardness, while the N component has the effect of improving the high temperature strength. When the average content ratio Y _avg (atomic ratio) of exceeds 0.005, the high-temperature strength decreases. Therefore, the average content ratio Y _avg (atomic ratio) of the C component was determined as 0 ≦ Y _avg ≦ 0.005.

In general, the above composition, that is, the average Al content ratio X _avg (atomic ratio) is 0.60 or more and 0.95 or less (Ti _1-X Al _X ) (C _Y N _1-Y ) by physical vapor deposition. When the layer is formed, the crystal structure becomes a hexagonal structure, but in the present invention, since the film is formed by the chemical vapor deposition method described later, the composition as described above is maintained while maintaining the cubic structure. _{(Ti 1-X Al X)} (C Y N 1-Y) layer can be obtained. Thereby, the fall of the hardness of a hard coating layer is avoided.

Composite nitride of Ti and Al or composite carbonitride layer _{((Ti 1-X Al X} ) (C Y N 1-Y) layer) is an individual crystal grains the crystal surface having a cubic structure in the {100} Inclination angle number distribution on the surface:
For the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer of the present invention, when the crystal orientation of each crystal grain is analyzed from the longitudinal sectional direction using an electron beam backscattering diffractometer, There is a cubic crystal phase in which an electron backscatter diffraction image of the cubic crystal lattice is observed, which is the crystal plane of the crystal grain with respect to the normal of the substrate surface (direction perpendicular to the substrate surface in the cross-section polished surface) {100 } Measure the inclination angle formed by the normal of the surface (see FIGS. 1A and 1B), and set the inclination angle within the range of 0 to 45 degrees with respect to the normal direction among the inclination angles to 0. When the frequency existing in each section is tabulated by dividing each pitch by 25 degrees, the highest peak exists in the inclination angle section in the range of 0 to 12 degrees, and within the range of 0 to 12 degrees. The total of the existing frequencies is a ratio of 45% or more of the total frequencies in the tilt angle frequency distribution. The hard coating layer made of the composite nitride or composite carbonitride layer of Ti and Al has a high hardness while maintaining the cubic structure, Such an inclination angle number distribution form dramatically improves the adhesion between the hard coating layer and the substrate.
Therefore, even when such a coated tool is used for, for example, high-speed intermittent cutting of stainless steel, the occurrence of chipping, chipping, peeling and the like is suppressed, and excellent wear resistance is exhibited.
When analyzing the crystal orientation of each crystal grain using an electron beam backscattering diffractometer, a crystal plane with an inclination angle larger than 12 degrees cannot be regarded as being {100} oriented, and the hardness decreases. The range where the {100} orientation is strong and the hardness does not decrease is 0 to 12 degrees, and the inclination angle section is set to 0 to 12 degrees.

Individual crystal grains having a cubic structure in a composite nitride or composite carbonitride layer of Ti and Al ((Ti _1-X Al _X ) (C _Y N _1-Y ) layer) are perpendicular to the layer thickness direction. 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 grain, the facet Area ratio when the whole is 100% in a plane perpendicular to the thickness direction:
When the structure of the composite nitride or composite carbonitride layer is observed with a scanning electron microscope from the surface side, individual crystal grains having a cubic structure in the composite nitride or composite carbonitride layer are layers. A polygonal facet that does not have an angle of less than 90 degrees in a plane perpendicular to the thickness direction, and the facet is formed on one of the equivalent crystal planes represented by {100} of the crystal grains. In this case, it was found that wear resistance with the work material is reduced, initial conformability in cutting is improved, and chipping resistance is improved. If there is an angle of less than 90 degrees, the load due to cutting increases at that angle, and the lubricity is impaired.
However, if the area ratio of the facet is less than 50% in the plane perpendicular to the layer thickness direction when the entire surface is taken as 100%, the above-described effects specific to the present invention are not sufficiently achieved, which is not preferable. . Therefore, the area ratio in the plane perpendicular to the layer thickness direction of the facet is set to 50% or more.

Peak intensity ratio Ic {200} / Ih {200} between peak intensity Ic {200} due to {200} having a cubic structure and peak intensity Ih {200} due to {200} having a hexagonal structure:
Although the composite nitride or composite carbonitride layer of the present invention has a crystal structure mainly composed of a cubic structure, the wear resistance is improved. However, as the proportion of the hexagonal structure increases, the composite nitride Since the hardness of a nitride or a composite carbonitride layer falls and abrasion resistance is impaired, it is unpreferable.
Therefore, when a hexagonal crystal structure exists, the relationship between the ratio of the cubic crystal structure to the hexagonal crystal structure and the wear resistance was investigated, and the peak intensity Ic {200} due to {200} of the cubic crystal structure and the hexagonal crystal structure It has been clarified that when the peak intensity ratio Ic {200} / Ih {200} to the peak intensity Ih {200} by {200} exceeds 3.0, the effect of improving the wear resistance is remarkably exhibited. Therefore, the peak intensity ratio Ic {200} / Ih {200} between the peak intensity Ic {200} due to {200} having a cubic structure and the peak intensity Ih {200} due to {200} having a hexagonal structure is 3.0. It is preferable to make it larger.
In addition, the value of Ic {200} exists in 43.59-44.77 degrees between the diffraction angles of the same crystal plane {200} shown in JCPDS00-038-1420 cubic TiN and JCPDS00-046-1200 cubic AlN. The value of Ih {200} is the peak intensity of the diffraction peak existing at 36.00 ° of the diffraction angle of the same crystal plane {200} shown in JCPDS00-025-1133 hexagonal AlN. To do.

Average layer thickness and particle size R of the layer having a fine hexagonal crystal structure:
In the present invention, a fine crystal grain layer having a hexagonal crystal structure can be provided as a lower layer of a columnar cubic crystal layer, whereby adhesion strength with the columnar cubic crystal layer is improved and toughness is improved. If the average layer thickness of the hexagonal fine crystal grain layer is less than 0.3 μm, the effect of improving toughness is not seen, and if it exceeds 1.0 μm, the hardness decreases and the wear resistance is impaired, so the average layer thickness is It is preferable to set it as 0.3-1.0 micrometer. Further, if the average grain size R of the fine crystal grains becomes too large, it is not preferable because the growth of the columnar structure of the upper layer is inhibited. Therefore, it is preferable that the average grain size R of the fine crystal grains of the layer made of fine hexagonal crystals is 0.01 to 0.30 μm.

Film formation of the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer of the present invention includes, for example, a tool base or a Ti carbide layer, a nitride layer, a carbonitride layer, a carbonate layer, and a carbonitride. In the case where only a cubic layer is formed over the oxide layer, a layer having a columnar cubic structure and a polygonal structure on the surface is formed. When a granular hexagonal layer and a columnar cubic layer are formed, the first step is used to form a granular hexagonal layer, and then the second step is used to form a columnar cubic crystal having a polygonal surface. It can be performed by a two-stage vapor deposition method in which a layer having a structure is formed.

The (Ti _1-X Al _X ) (C _Y N _1-Y ) layer of the present invention is formed from a columnar cubic single layer, or a granular hexagonal layer and a columnar cubic crystal using an ordinary chemical vapor deposition apparatus. Two layers are formed under the following conditions.
≪First stage≫
Reaction gas composition (volume%):
NH ₃ 6-10%, TiCl ₄ 0.5-1.5%, AlCl ₃ 3-5%, N ₂ 6-11%, remaining H ₂ ,
Reaction atmosphere temperature: 800-900 ° C
Reaction atmosphere pressure: 2 to 5 kPa,
Particulate hexagonal a _{(Ti 1-X Al X)} (C Y N 1-Y) layer was vapor deposited under the condition that,
≪Second stage≫
Reaction gas composition (volume%):
_{NH 3 2~6%, TiCl 4 0.1~0.5} %, AlCl 3 0.5~2.5%, N 2 10~15%, Al (CH 3) 3 0~0.5%, remainder : H ₂ ,
Reaction atmosphere temperature: 800-900 ° C
Reaction atmosphere pressure: 2-3 kPa,
Performing vapor deposition formation of columnar cubic predetermined target layer thickness of crystal of _{(Ti 1-X Al X)} (C Y N 1-Y) layer by changing the gas composition and reaction atmosphere temperature under the condition that. In the case of forming only a layer having a columnar cubic crystal and a polygonal shape on the surface, vapor deposition is performed under the above-mentioned second stage condition.

The coated tool of the present invention is obtained, for example, by chemical vapor deposition such as thermal CVD containing trimethylaluminum (Al (CH ₃ ) ₃ ) as a reaction gas component, with a composition formula: (Ti _1-X Al _X ) (C _Y N _{1 -Y} ), the average content ratio X _avg in the total amount of Ti and Al in Al and the average content ratio Y _avg in the total amount of C and N in C (where X _avg and Y _avg are The hard coating layer is composed of a composite nitride or a composite carbonitride layer having a cubic structure, each satisfying an atomic ratio of 0.60 ≦ X _avg ≦ 0.95 and 0 ≦ Y _avg ≦ 0.005, respectively. The hard coating layer is formed by using an electron beam backscatter diffractometer to change the crystal orientation of the individual crystal grains having a cubic structure in the composite nitride or composite carbonitride layer, the Ti and Al Analysis of the composite nitride or composite carbonitride layer from the longitudinal section In this case, the inclination angle formed by the normal line of the {100} plane which is the crystal plane of the crystal grain with respect to the normal direction of the tool base surface is measured, and the range of 0 to 45 degrees with respect to the normal direction of the inclination angle. When the inclination angle within the range is divided into 0.25 degree pitches and the frequencies existing in each division are tabulated and the inclination angle number distribution is obtained, it is the highest in the inclination angle division within the range of 0 to 12 degrees. The sum of the frequencies existing in the range of 0 to 12 degrees with a peak presents a ratio of 45% or more of the total frequencies in the tilt angle frequency distribution, and the composite nitride or composite carbonitride layer When the structure of the layer is observed with a scanning electron microscope from the surface side, the individual crystal grains having a cubic structure in the composite nitride or composite carbonitride layer are 90 in a plane perpendicular to the layer thickness direction. Represented by {100} of the crystal grains having a polygonal shape having no angle less than The facet formed with an equivalent crystal plane that occupies 50% or more of the total area in the plane perpendicular to the layer thickness direction is accompanied by high heat generation, and the cutting edge Even when used for high-speed intermittent cutting such as stainless steel that is subjected to intermittent and impact loads, it exhibits excellent wear resistance over long-term use without causing abnormal damage such as chipping, chipping, and peeling. To do.

(A), (b) is an equivalent represented by a {100} plane which is a crystal plane of a crystal grain in the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer constituting the hard coating layer. It is a schematic explanatory drawing which shows the measuring range of the inclination angle which the normal line of (001) plane which is one of crystal planes makes with respect to the normal line of a substrate surface. It is an example of the inclination angle number distribution graph of the {100} plane created about the composite nitride or composite carbonitride of Ti and Al of this invention coated tool. An example of the observation image by the scanning electron microscope of the hard coating layer surface of this invention coated tool is shown.

The present invention provides a surface coating in which a hard coating layer is provided on the surface of a tool base made of an ultra-hard tool material such as a tungsten carbide-based cemented carbide, a titanium carbonitride-based cermet, or a cubic boron nitride-based ultra-high pressure sintered body. A cutting tool, wherein the hard coating layer includes at least a composite nitride or composite carbonitride layer of Ti and Al having an average layer thickness of 1 to 20 μm formed by a chemical vapor deposition method, and has a composition formula: (Ti _{1− X} Al _{X) (when} expressed in C _{Y N 1-Y),} the average content of Y _avg occupying the total amount of the average content ratio X _avg and C of C and N occupying the total amount of Ti and Al Al (although , X _avg , and Y _avg are both atomic ratios) satisfy 0.60 ≦ X _avg ≦ 0.95 and 0 ≦ Y _avg ≦ 0.005, respectively, and constitute a composite nitride or composite carbonitride layer There are those having a cubic structure in the crystal grains, For the compound nitride or composite carbonitride layer, the crystal orientation of each crystal grain was analyzed from the longitudinal cross-sectional direction of the Ti and Al composite nitride or composite carbonitride layer using an electron beam backscatter diffraction device. If there is a cubic crystal phase in which an electron backscattering diffraction image of a cubic crystal lattice is observed, and the analysis is performed from the longitudinal section direction of the Ti and Al composite nitride or composite carbonitride layer, the surface of the tool substrate The inclination angle formed by the normal line of the {100} plane which is the crystal plane of the crystal grain with respect to the normal direction is measured, and an inclination angle within the range of 0 to 45 degrees with respect to the normal direction is included in the inclination angle. When the pitch is divided into 0.25 degree pitches and the frequencies existing in each section are tabulated and the inclination angle number distribution is obtained, the highest peak is present in the inclination angle section within the range of 0 to 12 degrees, The total number of frequencies existing in the range of 0 to 12 degrees is 45% or more of the entire frequency in the tilt angle number distribution, and when the structure of the composite nitride or composite carbonitride layer is observed with a scanning electron microscope from the surface side, the composite nitridation The individual crystal grains having a cubic structure in the metal or composite carbonitride layer have a polygonal shape having no angle of less than 90 degrees in a plane perpendicular to the layer thickness direction, and {100} of the crystal grains The facets formed by the equivalent crystal planes represented by the present invention occupy 50% or more of the total area in the plane perpendicular to the layer thickness direction, resulting in high heat generation. Even when used for high-speed intermittent cutting of stainless steel where intermittent and impact loads are applied to the cutting edge, it has excellent wear resistance over long-term use without causing abnormal damage such as chipping, chipping and peeling. The effect of demonstrating As long as it exhibits the form of its specific implementation, it may be any one.
Next, the coated tool of the present invention will be specifically described based on examples.

As raw material powders, WC powder, TiC powder, ZrC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder all having an average particle diameter of 1 to 3 μm were prepared. 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. Substrates A to D made of WC-base cemented carbide having an ISO standard SEEN1203AFSN insert shape after vacuum sintering under vacuum at a predetermined temperature in the range of 1370 to 1470 ° C. for 1 hour. Were manufactured respectively.

In addition, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder, all having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and 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 pressed into a compact at a pressure of 98 MPa. The green compact was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1540 ° C. for 1 hour, and after sintering, a substrate made of TiCN-based cermet having an insert shape of ISO standard SEEN1203AFSN b was produced.

Next, a normal chemical vapor deposition apparatus is used on the surfaces of the tool bases A to D and the tool bases a and b, and first, under the conditions shown in Table 4, the composition has a predetermined composition (Ti _1-X Al _X ) The coated tools 1 to 15 of the present invention shown in Table 7 were manufactured by vapor-depositing the (C _Y N _1-Y ) layer until the target layer thickness was reached.
In addition, about this invention coated tools 6-13, the lower layer shown in Table 6 and / or the upper layer shown in Table 7 were formed on the formation conditions shown in Table 3.

Further, for the purpose of comparison, an ordinary chemical vapor deposition apparatus was similarly used on the surfaces of the tool bases A to D and the tool bases a and b, and under the conditions shown in Table 5, (Ti _1-X Al _X ) ( Comparative example-coated tools 1 to 13 shown in Table 8 were manufactured by vapor-depositing a C _Y N _1-Y ) layer with a target layer thickness.

For reference, the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer of the reference example is applied to the surfaces of the tool base A and the tool base a by arc ion plating using a conventional physical vapor deposition apparatus. Were formed by vapor deposition with a target layer thickness to produce reference example coated tools 14 and 15 shown in Table 8.
The conditions for arc ion plating are as follows.
(A) The tool bases A and a are ultrasonically cleaned in acetone and dried, and at the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table in the arc ion plating apparatus. Along with this, an Al-Ti alloy having a predetermined composition is arranged as a cathode electrode (evaporation source),
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 10 ⁻² Pa or less, the inside of the apparatus is heated to 500 ° C. with a heater, and then the tool base that rotates while rotating on the rotary table is −1000 V. A DC bias voltage is applied, and a current of 200 A is passed between a cathode electrode and an anode electrode made of an Al—Ti alloy to generate an arc discharge, thereby generating Al and Ti ions in the apparatus, thereby providing a tool base. Clean the surface with bombard,
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 4 Pa, a DC bias voltage of −50 V is applied to the tool base that rotates while rotating on the rotary table, and A current of 120 A is passed between the cathode electrode (evaporation source) made of the Al—Ti alloy and the anode electrode to generate an arc discharge, and the target average composition and target shown in Table 8 are formed on the surface of the tool base. the average layer thickness of _{(Ti 1-X Al X)} (C Y N 1-Y) layer and the vapor deposited,
Reference Example Coated tools 14 and 15 were produced.

Moreover, the longitudinal cross-section of each component layer of this invention coated tool 1-15, comparative example coated tool 1-13, and reference example coated tool 14,15 was measured using a scanning electron microscope, and five points within the observation visual field were measured. When the layer thickness was measured and averaged to determine the average layer thickness, both showed the average layer thickness substantially the same as the target average layer thickness shown in Tables 7 and 8.
Next, with respect to the hard coating layers of the above-described coated tools 1 to 15 of the present invention, the average Al content ratio X _avg , the average C content ratio Y _avg of the hard coating layer, and the peak intensity Ic {200 due to {200} of the cubic structure in XRD. } And the peak intensity ratio Ic {200} / Ih {200} between the peak intensity Ih {200} due to {200} of the hexagonal crystal structure, and the inclination angle formed by the normal of the {100} plane with respect to the normal direction of the substrate surface The ratio (α) of the frequency existing in the range of 0 to 12 degrees in the inclination angle frequency distribution was measured.
Further, by observing the surface of the hard coating layer using a scanning electron microscope and analyzing the image of the observed image, the equivalent crystal plane represented by {100} of the {100} -oriented crystal grains is obtained. The area ratio (β) of the facet having a polygonal shape that does not have an angle of less than 90 degrees when the entire observation image is 100% was measured.
In addition, FIG. 2 shows an example of a {100} plane inclination angle number distribution graph measured for the coated tool of the present invention.
Moreover, an example of the observation image by the scanning electron microscope of the hard coating layer surface of this invention coated tool is shown in FIG. 3 (a), and the schematic diagram is shown in FIG.3 (b).

The specific measuring methods for each of the above are as follows.
The average Al content ratio X _avg and the average C content ratio Y _avg of the hard coating layer were determined 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 Al content ratio X _avg and the average C content ratio Y _avg indicate average values in the depth direction.

  In addition, regarding the inclination angle number distribution of the hard coating layer, field emission scanning electrons are obtained with the cross section of the hard coating layer made of a composite nitride or composite carbonitride layer of Ti and Al having a cubic structure as a polished surface. A cubic crystal lattice that is set in a lens barrel of a microscope and has an electron beam with an acceleration voltage of 15 kV at an incident angle of 70 degrees and an irradiation current of 1 nA on the polished surface is present in the measurement range of the polished surface of the cross section. Irradiate each individual crystal grain, and use a backscatter diffraction imaging device, the normal surface of the substrate surface (cross-section polished surface) at a spacing of 0.1 μm / step with respect to the hard substrate over a length of 100 μm in the horizontal direction from the tool substrate. The tilt angle formed by the normal line of the {100} plane which is the crystal plane of the crystal grain is measured with respect to the direction perpendicular to the substrate surface of Measurements in the range of ~ 45 degrees The inclination angle was divided for each pitch of 0.25 degrees, and the frequencies (α) existing in the range of 0 to 12 degrees were obtained by counting the frequencies existing in each section.

  In addition, the surface of the hard coating layer has an angle of less than 90 degrees in a plane perpendicular to the layer thickness direction formed by an equivalent crystal plane represented by {100} of {100} plane oriented crystal grains. The area ratio of the facets having a polygonal shape not to be measured is measured using a scanning electron microscope and image analysis software accompanying the scanning electron microscope. Specifically, the measurement was performed as follows. First, the surface of the hard coating layer is observed with a scanning electron microscope in a range of 100 μm × 100 μm. While observing the observed image on the monitor, the facets having a polygonal shape not having an angle of less than 90 degrees, that is, crystal planes to be observed in the image plane are marked, and all the angles of less than 90 degrees are present. When the marking on the facet having a polygonal shape not to be finished was completed, the area ratio (β) of the entire area of the marked facet with respect to the entire observation image plane was obtained.

As for the crystal structure of the hard coating layer, when X-ray diffraction is performed using an X-ray diffractometer and Cu—Kα ray as a radiation source, JCPDS00-038-1420 cubic TiN and JCPDS00-046-1200 cubic crystal A diffraction peak appears between the diffraction angles of the same crystal plane shown in each of AlN (for example, 36.66 to 38.53 °, 43.59 to 44.77 °, 61.81 to 65.18 °). Investigated by confirming.
Table 7 shows the results.

Subsequently, the average Al content ratio X _avg and the average C content ratio Y of the hard coating layer were also obtained for each of the comparative coated tools 1 to 13 and the reference coated tools 14 and 15 in the same manner as the coated tools 1 to 15 of the present invention. _avg , a peak intensity ratio Ic {200} / Ih {200} between a peak intensity Ic {200} due to {200} of a cubic structure in XRD and a peak intensity Ih {200} due to {200} in a hexagonal structure, The ratio (α) of the frequency existing in the range of 0 to 12 degrees in the tilt angle number distribution with respect to the tilt angle formed by the normal of the {100} plane with respect to the normal direction, and the marked facet for the entire observation image plane The area ratio (β) of the entire area was determined.
Further, the crystal structure of the hard coating layer was also investigated in the same manner as the coated tools 1 to 15 of the present invention. Table 8 shows the results.

Next, in the state where each of the above various coated tools is clamped to a tool steel cutter tip portion having a cutter diameter of 125 mm by a fixing jig, the coated tools 1 to 15 of the present invention, the comparative coated tools 1 to 13 and the reference Example For coated tools 14 and 15, the following dry high-speed face milling, which is a kind of high-speed intermittent cutting of alloy steel, center-cut cutting test (normal rotation speed, cutting speed, cutting, single-blade feed amount are respectively 800 min ⁻¹ , 200 m / min, 1.0 mm, 0.08 mm / tooth), and the flank wear width of the cutting edge was measured.
Work material: Block material of JIS / SCM440 width 100mm, length 400mm
Rotational speed: 955 min ⁻¹
Cutting speed: 375 m / min,
Cutting depth: 1.0mm,
Single blade feed amount: 0.10 mm / tooth,
Cutting time: 8 minutes,
Table 9 shows the results of the cutting test.

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 diameter of 1 to 3 μm are prepared. Compounded in the formulation shown in Table 10, added with wax, ball mill mixed in acetone for 24 hours, dried under reduced pressure, press-molded into a green compact of a predetermined shape at a pressure of 98 MPa. In a 5 Pa vacuum, vacuum sintering is performed at a predetermined temperature within a range of 1370 to 1470 ° C. for 1 hour, and after sintering, the cutting edge is subjected to honing processing with an R of 0.07 mm. Tool bases α to γ made of a WC-base cemented carbide having an insert shape of CNMG12041 were manufactured.

  In addition, as raw material powder, TiCN (mass ratio TiC / TiN = 50/50) powder, NbC powder, WC powder, Co powder, and Ni powder all having an average particle diameter of 0.5 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, a normal chemical vapor deposition apparatus is used on the surfaces of the tool base α to γ and the tool base δ, and first, under the conditions shown in Table 4, (Ti _1-X Al _X ) ( The present invention coated tools 16 to 30 shown in Table 13 were manufactured by vapor-depositing the C _Y N _1-Y ) layer until the target layer thickness was reached.
In addition, about this invention coated tools 19-28, the lower layer shown in Table 12 and / or the upper layer shown in Table 13 were formed on the formation conditions shown in Table 3.

Further, for the purpose of comparison, (Ti _1-X Al _X ) (C) of the comparative example was similarly used on the surfaces of the tool bases α to γ and the tool base δ using the usual chemical vapor deposition apparatus under the conditions shown in Table 5. _{YN 1-Y} ) layers were deposited at the target layer thickness to produce comparative example coated tools 16-28 shown in Table 14.
As with the present invention coated tools 19 to 28, the comparative example coated tools 19 to 28 were formed with the lower layer shown in Table 12 and / or the upper layer shown in Table 14 under the formation conditions shown in Table 3. Formed.

For reference, the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer of the reference example is formed on the surfaces of the tool base β and the tool base γ by arc ion plating using a conventional physical vapor deposition apparatus. Were formed by vapor deposition with a target layer thickness to produce reference example coated tools 29 and 30 shown in Table 14.
In addition, the conditions similar to the conditions shown in Example 1 were used for the conditions of arc ion plating.

Moreover, the cross section of each component layer of this invention coated tool 16-30, comparative example coated tool 16-28, and reference example coated tool 29,30 is measured using a scanning electron microscope, and five layers in an observation visual field When the thickness was measured and averaged to determine the average layer thickness, both showed the same average layer thickness as the target average layer thickness shown in Table 13 and Table 14.
Next, with respect to the hard coating layers of the above-described coated tools 16 to 30 of the present invention, the average Al content ratio X _avg , the average C content ratio Y _avg of the hard coating layer, and the peak intensity Ic {200 due to {200} of the cubic structure in XRD. } And the peak intensity ratio Ic {200} / Ih {200} between the peak intensity Ih {200} due to {200} of the hexagonal crystal structure, and the inclination angle 0 formed by the normal of the {100} plane with respect to the normal direction of the substrate surface The ratio (α) of the frequency existing in the range of ˜12 degrees and the area ratio (β) of the entire area of the marked facet with respect to the entire observation image plane were obtained. Furthermore, the crystal structure of the hard coating layer was measured using the same method as shown in Example 1.
Table 13 shows the results.

Then, the average Al content ratio X _avg and the average C content ratio Y of the hard coating layer were also applied to each of the comparative coated tools 16 to 28 and the reference coated tools 29 and 30 in the same manner as the coated tools 16 to 30 of the present invention. _avg , a peak intensity ratio Ic {200} / Ih {200} between a peak intensity Ic {200} due to {200} of a cubic structure in XRD and a peak intensity Ih {200} due to {200} in a hexagonal structure, The ratio (α) of the power existing within the inclination angle of 0 to 12 degrees formed by the normal of the {100} plane with respect to the normal direction of the image and the area ratio of the entire area of the marked facet to the entire observation image plane (β ) Furthermore, the crystal structure of the hard coating layer was measured using the same method as shown in Example 1.
Table 14 shows the results.

Next, the coated tools 16 to 30 of the present invention, the comparative coated tools 16 to 28, and the reference coated tools are used in the state where all of the various coated tools are screwed to the tip of the tool steel tool with a fixing jig. About 29 and 30, the dry high-speed intermittent cutting test of carbon steel and the wet high-speed intermittent cutting test of cast iron which were shown below were implemented, and all measured the flank wear width of the cutting edge.
Cutting condition 1:
Work material: JIS · SCM435 lengthwise equally spaced four round grooved round bars,
Cutting speed: 380 m / min,
Cutting depth: 1.0 mm,
Feed: 0.2mm / rev,
Cutting time: 5 minutes
(Normal cutting speed is 220 m / min),
Cutting condition 2:
Work material: JIS / FCD700 lengthwise equal length 4 round bar with round groove,
Cutting speed: 310 m / min,
Cutting depth: 1.0 mm,
Feed: 0.2mm / rev,
Cutting time: 5 minutes
(Normal cutting speed is 180 m / min),
Table 15 shows the results of the cutting test.

As the raw material powder, cBN powder, TiN powder, TiCN powder, TiC powder, Al powder, and Al ₂ O ₃ powder each having an average particle diameter in the range of 0.5 to 4 μm are prepared. The mixture is blended in the composition shown in FIG. 1, wet mixed with a ball mill for 80 hours, dried, and then pressed into a green compact having a diameter of 50 mm × thickness: 1.5 mm under a pressure of 120 MPa. The green compact is sintered in a vacuum atmosphere at a pressure of 1 Pa at a predetermined temperature within a range of 900 to 1300 ° C. for 60 minutes to obtain a presintered body for a cutting edge piece. In addition, Co: 8% by mass, WC: remaining composition, and diameter: 50 mm × thickness: 2 mm, superposed on a WC-based cemented carbide support piece with a normal super-high pressure Insert into the sintering machine, normal conditions A certain pressure: 4 GPa, temperature: 1200 ° C. to 1400 ° C. within a predetermined temperature, holding time: 0.8 hour sintering, and after sintering, the upper and lower surfaces are polished with a diamond grindstone, and wire discharge It is divided into predetermined dimensions by a processing apparatus, and further Co: 5 mass%, TaC: 5 mass%, WC: remaining composition and shape of JIS standard CNGA12041 (thickness: 4.76 mm × inscribed circle diameter: 12. The brazing part (corner part) of the WC-based cemented carbide insert body having a 7 mm 80 ° rhombus) has a composition consisting of Zr: 37.5%, Cu: 25%, Ti: the rest in mass%. After brazing using a brazing material of Ti-Zr-Cu alloy and having a predetermined dimension, the cutting edge is subjected to honing with a width of 0.13 mm and an angle of 25 °, followed by finishing polishing. ISO regulations The tool substrate (a) to (k) two having the insert shape of CNGA120412 were produced, respectively.

Then, these tool substrate i ~ the surface of the two, using a conventional chemical vapor deposition apparatus under the conditions shown in Table _{3, (Ti 1-X Al} X) of the present invention (C _{Y N 1-Y)} layer The present invention coated tools 31 to 40 shown in Table 18 were manufactured by vapor deposition with a target layer thickness. In addition, about this invention coated tools 34-38, the lower layer shown in Table 17 and / or the upper layer shown in Table 18 were formed on the formation conditions shown in Table 3.

Further, for the purpose of comparison, (Ti _1-X Al _X ) (C _Y N _1-Y ) of the comparative example was similarly formed on the surfaces of the tool bases a to d under the conditions shown in Table 4 using a normal chemical vapor deposition apparatus. The comparative example coated tools 31-39 shown in Table 19 were manufactured by vapor-depositing layers with the target layer thickness.

For reference, the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer of the reference example is formed on the surface of the tool base A by a conventional physical vapor deposition device and arc ion plating with a target layer thickness. The reference example-coated tool 40 shown in Table 19 was manufactured by vapor deposition.
The arc ion plating conditions are the same as the conditions shown in Example 1, and the target average composition and target average layer thickness (Ti _1-X shown in Table 19) are formed on the surface of the tool base. An Al _X ) (C _Y N _1-Y ) layer was formed by vapor deposition to produce a reference example-coated tool 40.

Moreover, the cross section of each component layer of this invention coated tool 31-40, comparative example coated tool 31-39, and reference example coated tool 40 is measured using a scanning electron microscope, and the layer thickness of five points in an observation visual field is measured. When measured and averaged to determine the average layer thickness, both showed the average layer thickness substantially the same as the target average layer thickness shown in Table 18 and Table 19.
Next, with respect to the hard coating layers of the above-described coated tools 31 to 40 of the present invention, the average Al content ratio X _avg , the average C content ratio Y _avg of the hard coating layer, and the peak intensity Ic {200 due to {200} of the cubic structure in XRD. } And the peak intensity ratio Ic {200} / Ih {200} between the peak intensity Ih {200} due to {200} of the hexagonal crystal structure, and the inclination angle 0 formed by the normal of the {100} plane with respect to the normal direction of the substrate surface The ratio (α) of the frequency existing in the range of ˜12 degrees and the area ratio (β) of the entire area of the marked facet with respect to the entire observation image plane were obtained. Furthermore, the crystal structure of the hard coating layer was measured using the same method as shown in Example 1.
Table 18 shows the results.

Next, for each of the comparative example coated tools 31 to 39 and the reference example coated tool 40, the average Al content ratio X _avg , the average C content ratio Y _{avg of} the hard coating layer is the same as in the present invention coated tools 31 to 40. The peak intensity ratio Ic {200} / Ih {200} between the peak intensity Ic {200} due to {200} in the cubic structure and the peak intensity Ih {200} due to {200} in the hexagonal structure in XRD, the method of the substrate surface The ratio (α) of the frequency existing in the range of the inclination angle of 0 to 12 degrees formed by the normal of the {100} plane with respect to the line direction and the area ratio (β) of the entire area of the marked facet to the entire observation image plane Asked. Furthermore, the crystal structure of the hard coating layer was measured using the same method as shown in Example 1.
Table 19 shows the results.

Next, in the state where each of the above various coated tools is screwed to the tip of the tool steel tool with a fixing jig, the present coated tools 31 to 40, the comparative coated tools 31 to 39, and the reference coated samples About the tool 40, the dry high-speed intermittent cutting test of the carburizing hardening alloy steel shown below was implemented, and the flank wear width of the cutting edge was measured.
Work material: JIS · SCr420 (Hardness: HRC60) lengthwise equidistant 4 round bars with longitudinal grooves,
Cutting speed: 235 m / min,
Cutting depth: 0.12mm,
Feed: 0.1mm / rev,
Cutting time: 5 minutes
Table 20 shows the results of the cutting test.

From the results shown in Tables 7 to 9, Tables 13 to 15, and Tables 18 to 20, the coated tools 1 to 40 of the present invention are (Ti _1-X Al _X ) (C _Y N _1-Y ) layers having a cubic structure. Is formed, and the value of α in the entire distribution of the number of tilt angles is 45% or more and less than 90 degrees formed by an equivalent crystal plane represented by {100} of {100} -oriented crystal grains. Since the area ratio when the entire surface of the facet having a polygonal shape without an angle is 100% is 50% or more, it has excellent chipping resistance and wear resistance in high-speed intermittent cutting processing such as stainless steel. Demonstrate.
On the other hand, all of the comparative example coated tools 1 to 13, 16 to 28, 31 to 39 and the reference example coated tools 9, 10, 14, 15, and 40 are chipped, chipped, peeled, etc. on the hard coating layer. It is clear that not only abnormal damage occurs, but also the service life is reached in a relatively short time.

  As described above, the coated tool of the present invention can be used not only for high-speed intermittent cutting of stainless steel, carbon 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 respond to higher performance of cutting equipment, labor saving and energy saving of cutting, and cost reduction.

Claims (8)

In a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool base composed of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh-pressure sintered body,
The hard coating layer includes at least a composite nitride or composite carbonitride layer of Ti and Al having an average layer thickness of 1 to 20 μm formed by chemical vapor deposition, and has a composition formula: (Ti _1-X Al _X ) ( C _Y N _1-Y ), the average content ratio X _avg in the total amount of Ti and Al in Al and the average content ratio Y _avg in the total amount of C and N in C (where X _avg , Y _avg is an atomic ratio) satisfying 0.60 ≦ X _avg ≦ 0.95 and 0 ≦ Y _avg ≦ 0.005, respectively.
The composite nitride or composite carbonitride layer includes at least a Ti and Al composite nitride or composite carbonitride phase having a NaCl-type face-centered cubic structure,
For the composite nitride or composite carbonitride layer, the crystal orientation of each crystal grain is analyzed from the longitudinal cross-sectional direction of the Ti and Al composite nitride or composite carbonitride layer using an electron beam backscattering diffractometer. In this case, there is a cubic crystal phase in which an electron backscatter diffraction image of the cubic crystal lattice is observed, and an electron beam backscatter diffractometer is used to change the cubic structure in the composite nitride or composite carbonitride layer. When the crystal orientation of the individual crystal grains is analyzed from the longitudinal cross-sectional direction of the Ti and Al composite nitride or composite carbonitride layer, it is the crystal plane of the crystal grains with respect to the normal direction of the tool base surface { Inclination angle formed by the normal line of the 100} plane is measured, and the inclination angle within the range of 0 to 45 degrees with respect to the normal direction is divided for each 0.25 degree pitch. Count the frequencies present in the When the highest peak exists in the inclination angle section within the range of 0 to 12 degrees, the total 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. Show the percentage,
Further, when the structure of the composite nitride or composite carbonitride layer is observed with a scanning electron microscope from the surface side, the individual crystals having a cubic structure in the composite nitride or composite carbonitride layer One of the equivalent crystal faces represented by {100} of the crystal grains, wherein the grains have polygonal facets that do not have an angle of less than 90 degrees in a plane perpendicular to the layer thickness direction. A surface-coated cutting tool characterized in that the facet occupies an area ratio of 50% or more of the whole in a plane perpendicular to the layer thickness direction. 2. The surface according to claim 1, wherein the composite nitride or composite carbonitride layer is composed of a single phase of Ti and Al composite nitride or composite carbonitride having a NaCl-type face-centered cubic structure. Coated cutting tool. The composite nitride or composite carbonitride layer is composed of a mixed phase in which two or more kinds of phases coexist, and the mixed phase is a composite nitride or composite of Ti and Al having an NaCl type face-centered cubic structure. Each of the other phases coexisting in the mixed phase including at least a carbonitride phase is composed of a compound composed of at least one element selected from Ti and Al and at least one element selected from C and N. The surface-coated cutting tool according to claim 1.   When a crystal structure analysis by X-ray diffraction is performed on the composite nitride or the composite carbonitride layer, a peak derived from a cubic structure and a peak derived from a hexagonal crystal are observed, and the cubic structure is {200} The peak intensity ratio Ic {200} / Ih {200} between the peak intensity Ic {200} and the peak intensity Ih {200} due to {200} having a hexagonal structure is greater than 3.0. 3. The surface-coated cutting tool according to 3.   The composite nitride or composite carbonitride layer is composed of an upper layer having a cubic structure and a lower layer having a hexagonal structure, and the average layer thickness of the lower layer is 0.3 to 1.0 μm, 5. The surface-coated cutting tool according to claim 1, wherein the average particle diameter R of the grains is 0.01 to 0.30 μm.   Between a tool base composed of any one of the tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh pressure sintered body, and the Ti / Al composite nitride or composite carbonitride layer. And consisting of one or more of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride layer, and a total average layer thickness of 0.1 to 20 μm. The surface-coated cutting tool according to any one of claims 1 to 5, wherein a Ti compound layer is present.   7. The upper layer including an aluminum oxide layer having an average layer thickness of at least 1 to 25 μm exists above the composite nitride or composite carbonitride layer. The surface-coated cutting tool described.   The composite nitride or composite carbonitride layer is formed by a chemical vapor deposition method containing at least trimethylaluminum as a reaction gas component, according to any one of claims 1 to 7. The surface-coated cutting tool described.