WO2020070967A1

WO2020070967A1 - Surface coated cutting tool and production method therefor

Info

Publication number: WO2020070967A1
Application number: PCT/JP2019/030709
Authority: WO
Inventors: 福井　治世; 瀬戸山　誠; 田中　敬三
Original assignee: 住友電工ハードメタル株式会社
Priority date: 2018-10-03
Filing date: 2019-08-05
Publication date: 2020-04-09
Also published as: JPWO2020070967A1; JP7055961B2

Abstract

This surface coated cutting tool comprises a base material and a coating layer that covers the base material, the coating layer includes an alternating layer wherein first unit layers and a second unit layers are layered alternatingly, each of the first unit layers comprises a nitride containing aluminum and zirconium, the ratio of the number of the zirconium atoms in the first unit layer being between 0.65 and 0.95 inclusive when the total number of the metal atoms constituting the first unit layer is represented by 1, and each of the second unit layers comprises a nitride containing vanadium and aluminum, the ratio of the number of the aluminum atoms in the second unit layer being between 0.40 and 0.75 inclusive when the total number of the metal atoms constituting the second unit layer is represented by 1.

Description

Surface coated cutting tool and method of manufacturing the same

The present disclosure relates to a surface-coated cutting tool and a method for manufacturing the same. This application claims the priority based on Japanese Patent Application No. 2018-188077 filed on October 3, 2018. The entire contents described in the Japanese patent application are incorporated herein by reference.

In recent years, from the viewpoint of global environmental conservation, dry machining without using cutting oil has been demanded, cutting speed has been increased to improve machining efficiency, and work materials have been diversified. Particularly in the field of aircraft and medical treatment, the cutting edge temperature of the surface-coated cutting tool in the cutting process tends to be high due to the increase in cutting of heat-resistant alloys and the like, which are called difficult-to-cut materials. When the cutting edge temperature becomes high, the reaction between the surface-coated cutting tool and the work material becomes remarkable, and the life of the surface-coated cutting tool is shortened. Accordingly, there is a demand for a surface-coated cutting tool that can exhibit excellent tool life even under such severe cutting conditions.

For example, Japanese Patent Application Laid-Open No. 2003-34859 (Patent Document 1) discloses (Al _b , [Cr _{1 -e} V _e ] _c ) for the purpose of improving the wear resistance of a cutting tool in high-speed and high-efficiency cutting. Composition of (C _1-d N _d ) (provided that 0.5 ≦ b ≦ 0.8, 0.2 ≦ c ≦ 0.5, b + c = 1, 0.05 ≦ e ≦ 0.95, 0.5 ≦ d ≦ 1 or the composition of (M _a , Al _b , [Cr _{1 -e} V _e ] _c ) (C _{1 -d} N _d ) (where M is a group consisting of Ti, Nb, W, Ta and Mo) 0.02 ≦ a ≦ 0.3, 0.5 ≦ b ≦ 0.8, 0.05 ≦ c, a + b + c = 1, 0.5 ≦ d ≦ 1, 0 ≦ A coating layer consisting of e ≦ 1) is disclosed.

WO 2006/070730 (Patent Document 2) discloses an A layer made of a nitride of Al and Cr, and a nitride of Ti and Al for the purpose of performing dry processing at a high processing efficiency. And a coating layer including an alternating layer in which the layer B is alternately laminated.

JP-A-2003-34859 International Publication No. WO 2006/070730

Surface coating cutting tool according to one aspect of the present disclosure,
A substrate, a surface-coated cutting tool including a coating layer for coating the substrate,
The coating layer includes an alternating layer in which first unit layers and second unit layers are alternately stacked,
The first unit layer is made of a nitride containing aluminum and zirconium,
In the first unit layer, a ratio of the number of zirconium atoms is 0.65 or more and 0.95 or less when the total number of metal atoms constituting the first unit layer is 1.
The second unit layer is made of a nitride containing vanadium and aluminum,
In the second unit layer, a ratio of the number of aluminum atoms when the total number of metal atoms constituting the second unit layer is 1 is 0.40 or more and 0.75 or less. .

A method for manufacturing a surface-coated cutting tool according to another aspect of the present disclosure,
A method for producing a surface-coated cutting tool according to the above,
Preparing the substrate,
Forming the coating layer on the base material,
The step of forming the coating layer includes a step of forming the alternating layers by alternately laminating the first unit layers and the second unit layers using a physical vapor deposition method. It is a manufacturing method.

FIG. 1 is a schematic enlarged cross-sectional view of a surface-coated cutting tool according to an embodiment of the present disclosure. FIG. 2 is a schematic enlarged cross-sectional view of a surface-coated cutting tool according to another embodiment of the present disclosure. FIG. 3 is a schematic enlarged cross-sectional view of a surface-coated cutting tool according to another embodiment of the present disclosure. FIG. 4 is a schematic enlarged cross-sectional view of a surface-coated cutting tool according to another embodiment of the present disclosure. FIG. 5 is a diagram for explaining an example of the ratio of the thickness of the first unit layer and the thickness of the second unit layer. FIG. 6 is a schematic sectional view of the cathode arc ion plating apparatus used in the example. FIG. 7 is a schematic top view of the cathode arc ion plating apparatus shown in FIG.

[Problems to be solved by the present disclosure]
Heat-resistant alloys such as Inconel (registered trademark) used for aircraft engines and the like often contain Cr. The coating layers of

Patent Documents

1 and 2 described above contain Cr. Therefore, when a heat-resistant alloy is cut using these cutting tools, Cr in the coating layer and Cr in the work material tend to interdiffuse, and damage to the coating layer tends to be accelerated.

Further, when using a tool having a coating layer of Patent Document 1 and Patent Document 2 to cut a titanium alloy which is a difficult-to-cut material often used in the medical industry, the aircraft industry, and the like, the titanium alloy has high strength at high temperatures. Therefore, the cutting temperature increases during processing. Since the titanium alloy has a low thermal conductivity, heat tends to accumulate at the cutting edge of the tool during processing. Furthermore, since titanium alloys are chemically active at high temperatures, adhesive wear of the tool tends to progress.

Therefore, an object of the present invention is to provide a surface-coated cutting tool capable of achieving a long life even in the processing of difficult-to-cut materials.
[Effects of the present disclosure]
According to the above aspect, it is possible to provide a surface-coated cutting tool that can achieve a long life even in the processing of particularly difficult-to-cut materials.

[Description of Embodiment of the Present Disclosure]
First, embodiments of the present disclosure will be listed and described.

(1) A surface-coated cutting tool according to an aspect of the present disclosure includes:
A substrate, a surface-coated cutting tool including a coating layer for coating the substrate,
The coating layer includes an alternating layer in which first unit layers and second unit layers are alternately stacked,
The first unit layer is made of a nitride containing aluminum and zirconium,
In the first unit layer, a ratio of the number of zirconium atoms is 0.65 or more and 0.95 or less when the total number of metal atoms constituting the first unit layer is 1.
The second unit layer is made of a nitride containing vanadium and aluminum,
In the second unit layer, a ratio of the number of aluminum atoms when the total number of metal atoms constituting the second unit layer is 1 is 0.40 or more and 0.75 or less. .

Such a surface-coated cutting tool can achieve a long service life in machining difficult-to-cut materials.

(2) The ratio λ2 / λ1 of the thickness λ2 of the second unit layer to the thickness λ1 of the first unit layer in the adjacent first unit layer and the second unit layer in the alternate layer is 1 or more and 5 or more. The following is preferred.

According to this, since the total amount of aluminum in the film increases, the thermal insulation of the entire surface-coated cutting tool is improved, and in particular, the wear resistance of the surface-coated cutting tool during continuous cutting is improved.

(3) the first unit layer contains silicon;
In the first unit layer, the ratio of the number of silicon atoms when the total number of metal atoms constituting the first unit layer is 1 is preferably greater than 0 and 0.20 or less.

According to this, the coating layer can have high hardness.
(4) The second unit layer contains silicon,
In the second unit layer, the ratio of the number of silicon atoms when the total number of metal atoms constituting the second unit layer is 1 is preferably greater than 0 and 0.20 or less.

According to this, the coating layer can have high hardness.
(5) the first unit layer contains boron;
In the first unit layer, the ratio of the number of boron atoms when the total number of metal atoms constituting the first unit layer is 1 is preferably greater than 0 and 0.10 or less.

According to this, the coating layer can have high hardness.
(6) the second unit layer contains boron;
In the second unit layer, the ratio of the number of boron atoms when the total number of metal atoms constituting the second unit layer is 1 is preferably greater than 0 and 0.10 or less.

According to this, the coating layer can have high hardness.
(7) The first unit layer contains vanadium,
In the first unit layer, the ratio of the number of vanadium atoms when the total number of metal atoms constituting the first unit layer is 1 is preferably greater than 0 and 0.30 or less.

According to this, welding of the work material to the surface-coated cutting tool can be suppressed.
(8) It is preferable that each of the first unit layer and the second unit layer has a thickness of 0.002 μm or more and 0.2 μm or less. According to this, the development of cracks can be suppressed.

(9) the coating layer includes a base layer disposed between the base material and the alternating layer,
It is preferable that the underlayer has the same composition as the first unit layer or the second unit layer.

(4) When the base layer has the same composition as the first unit layer, even if the base material is exposed in the initial stage of cutting, it is possible to suppress oxidation from the interface between the base material and the coating layer. When the underlayer has the same composition as the second unit layer, the peeling resistance of the coating layer can be improved in the case of intermittent processing such as milling or end milling.

(10) The thickness of the underlayer is preferably 0.1 μm or more and 2 μm or less. According to this, the above-described effects of suppressing oxidation and peeling resistance can be obtained, and it is also advantageous in terms of cost.

(11) the coating layer includes a surface layer disposed on a surface side of the alternating layer;
The surface layer is made of carbonitride containing vanadium and aluminum,
In the surface layer, it is preferable that the ratio of the number of aluminum atoms when the total number of metal atoms constituting the surface layer is 1 is 0.40 or more and 0.75 or less.

According to this, the surface-coated cutting tool can achieve a longer life.
(12) A method for manufacturing a surface-coated cutting tool according to another aspect of the present disclosure is the method for manufacturing a surface-coated cutting tool according to any one of (1) to (11) above.
Preparing the substrate,
Forming the coating layer on the base material,
The step of forming the coating layer includes a step of forming the alternating layers by alternately laminating the first unit layers and the second unit layers using a physical vapor deposition method. It is a manufacturing method.

交互 The alternating layer formed by using the physical vapor deposition method has high crystallinity and can have excellent wear resistance. Therefore, the obtained surface-coated cutting tool can achieve a long life.

[Details of Embodiment of the Present Disclosure]
A specific example of the surface-coated cutting tool according to an embodiment of the present disclosure will be described below with reference to the drawings.

In the present specification, the notation in the form of “A to B” means the upper and lower limits of the range (that is, A or more and B or less), and when a unit is not described in A and a unit is described only in B, A And the unit of B are the same.

化合物 In the present specification, when a compound is represented by a chemical formula, if the atomic ratio is not particularly limited, it includes all conventionally known atomic ratios, and is not necessarily limited to only the stoichiometric range. For example, when simply describing “ZrAlN”, the atomic ratio between “Zr”, “Al”, and “N” includes any conventionally known atomic ratio.

[Embodiment 1: Surface-coated cutting tool]
A surface-coated cutting tool according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 4 are schematic enlarged cross-sectional views of a surface-coated cutting tool according to an embodiment of the present disclosure. FIG. 5 is a diagram for explaining an example of the ratio of the thickness of the first unit layer and the thickness of the second unit layer.

As shown in FIGS. 1 to 4, the surface-coated

cutting tools

1, 21, 31, and 41 according to the embodiment of the present disclosure include a base material 2 and

coating layers

3 and 23 that cover the base material 2. , 33, 43. It is preferable that the coating layers 3, 23, 33, and 43 cover the entire surface of the substrate 2, but a part of the substrate 2 is not covered with the coating layer or the configuration of the coating layer is partially different. Even if it does, it does not deviate from the scope of the present embodiment.

The surface-coated cutting tool of the present embodiment includes a drill, an end mill, a replaceable cutting tip for a drill, a replaceable cutting tip for an end mill, a replaceable cutting tip for milling, a replaceable cutting tip for turning, a metal saw, It can be suitably used as a cutting tool such as a gear cutting tool, a reamer, and a tap.

<Substrate>
As the substrate 2 used for the surface-coated

cutting tools

1, 21, 31, and 41 of the present embodiment, any conventionally known substrate of this type can be used. For example, cemented carbides (for example, WC-based cemented carbides, WCs, and alloys containing Co or containing carbonitrides such as Ti, Ta, Nb, etc.) and cermets (TiC, TiN, TiCN, etc.) are mainly used. Component), high-speed steel, ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, etc.), cubic boron nitride sintered body, or diamond sintered body preferable.

中でも Among these various substrates, it is particularly preferable to select WC-based cemented carbide and cermet (particularly TiCN-based cermet). Since these base materials have an excellent balance between hardness and strength, particularly at high temperatures, when used as base materials for surface-coated cutting tools, they can contribute to prolonging the life of the surface-coated cutting tools.

<Coating layer>
The coating layers 3, 23, 33, 43 included in the surface-coated

cutting tools

1, 21, 31, 41 of the present embodiment include an alternating layer 13 in which the first unit layer 12 and the second unit layer 15 are alternately stacked. , 13 '. The coating layers 3, 23, 33, 43 include, in addition to the alternating layers 13, 13 ', the base layer 16 disposed between the base material 2 and the alternating layers 13, 13', and the alternating layers 13, 13 '. A surface layer 14 disposed on the front side may be included.

The coating layer improves the wear resistance, chipping resistance, heat resistance, oxidation resistance, and other properties of the surface-coated cutting tool by coating the base material, and extends the life of the surface-coated cutting tool. Having.

The coating layer preferably has a total thickness of 0.8 μm or more and 15 μm or less. If the overall thickness of the coating layer is less than 0.8 μm, the thickness of the coating layer is too thin, and the life of the surface-coated cutting tool tends to be shortened. On the other hand, if it is thicker than 15 μm, the coating layer tends to chip at the beginning of cutting, and the life of the surface-coated cutting tool tends to be shortened. The total thickness of the coating layer can be measured by observing the cross section of the coating layer using a scanning electron microscope (SEM). Specifically, the observation magnification of the cross-sectional sample is set to 5,000 to 10,000 times, the observation area is set to 100 to 500 μm ² , and the thickness width of three arbitrarily selected spots in one visual field is measured, and the average value is referred to as “thickness”. And In this specification, when measuring thickness using SEM, it measures by the same method. Note that as long as the applicant has measured, as long as the measurement is performed on the same sample, even if the thickness measurement result is calculated a plurality of times by changing the selected part of the measurement visual field, there is almost no variation in the measurement result, and It was confirmed that setting the measurement field of view did not become arbitrary.

絶対 The compressive residual stress of the coating layer preferably has an absolute value of 6 GPa or less. The compressive residual stress of the coating layer is a kind of internal stress (intrinsic strain) existing in the entire coating layer, and is represented by a numerical value of “−” (minus) (unit: “GPa” is used in the present embodiment). Stress. For this reason, the concept that the compressive residual stress is large indicates that the absolute value of the numerical value is large, and the concept that the compressive residual stress is small indicates that the absolute value of the numerical value is small. That is, that the absolute value of the compressive residual stress is 6 GPa or less means that the residual stress of the coating layer is -6 GPa or more and 0 GPa or less.

(4) If the residual stress of the coating layer exceeds 0 GPa, it becomes a tensile stress, and therefore, there is a tendency that the development of cracks generated from the outermost surface of the coating layer cannot be suppressed. On the other hand, when the absolute value of the compressive residual stress exceeds 6 GPa, the stress is too large, and before the start of cutting, the coating layer may peel off, particularly from the edge portion of the surface-coated cutting tool, thereby shortening the life of the surface-coated cutting tool. There is.

The compressive residual stress is measured by a sin ² ψ method using an X-ray residual stress device (see “X-ray stress measurement method” (Japan Society of Materials Science, 1981, published by Yokendo Co., Ltd., pp. 54-66)). Can be.

結晶 The crystal structure of the coating layer is preferably cubic. When the crystal structure of the coating layer is cubic, the hardness of the coating layer is improved. Therefore, it is preferable that each of the layers in the coating layer has a cubic crystal structure. Note that the coating layer and the crystal structure of each layer in the coating layer can be analyzed by an X-ray diffractometer known in the art.

硬度 The hardness of the coating layer is preferably 29 GPa or more and 60 GPa or less, more preferably 40 GPa or more and 60 GPa or less. According to this, the coating layer has a sufficient hardness. The hardness of the entire coating layer can be measured by a nano indenter method (Nano Indenter XP manufactured by MTS). Specifically, the hardness at three locations on the surface of the coating layer is measured, and the average value is defined as “hardness”.

<Alternate layer>
In the present embodiment, the coating layers 3, 23, 33, 43 include alternating layers 13, 13 'in which the first unit layers 12 and the second unit layers 15 are alternately stacked. The first unit layer is made of a nitride containing aluminum (Al) and zirconium (Zr). In the first unit layer, the ratio of the number of zirconium atoms when the total number of metal atoms constituting the first unit layer is 1 Is 0.65 or more and 0.95 or less. The second unit layer is made of a nitride containing vanadium (V) and aluminum (Al). In the second unit layer, the ratio of the number of aluminum atoms when the total number of metal atoms constituting the second unit layer is 1 Is 0.40 or more and 0.75 or less.

In the present specification, "metal atom" refers to hydrogen, helium, neon, argon, krypton, xenon, radon, fluorine, chlorine, bromine, iodine, astatine, oxygen, sulfur, selenium, tellurium, nitrogen, phosphorus, arsenic, Refers to atoms of elements other than antimony and carbon.

In this specification, the composition of each layer including the first unit layer, the second unit layer, the underlayer, the intermediate layer, and the surface layer, and each atom (Zr, Al, Si, B, V with respect to the total number of metal atoms in each layer) ) Can be measured using an X-ray photoelectron spectrometer (XPS). Specifically, the surface of the sample is irradiated with X-rays, and the kinetic energy of photoelectrons emitted from the surface of the sample is measured to analyze the composition of the elements constituting the surface of the sample and the state of chemical bonding.

Since the “

alternate layers

13 and 13” have the above-described configuration, the surface-coated cutting tool according to the present embodiment has an excellent effect that a long life can be achieved even when machining a difficult-to-cut material. The reason is presumed to be as follows (i) to (vii).

(I) The first unit layer is made of a nitride containing Al and Zr. Since Al is easily oxidized, a dense oxide layer made of Al ₂ O ₃ is easily formed on the surface side of the coating layer. Furthermore, since Zr has a smaller standard energy of oxide generation than Al, it is more easily oxidized than Al, and a dense oxide layer made of ZrO ₂ is easily formed on the outermost surface of the coating layer. Since the oxidation resistance of the coating layer is improved by these oxide layers, the surface-coated cutting tool including the coating layer can achieve a long life even when machining a difficult-to-cut material.

(Ii) In the first unit layer, the ratio of the number of Zr atoms when the total number of metal atoms constituting the first unit layer is 1 is 0.65 or more and 0.95 or less. In this case, a paper by Makino (Makino, "Control of Crystal Structure and Properties of Pseudo-binary Nitride Hard Coating", Journal of the High Temperature Society of Japan, High Temperature Society of Japan, March 2007, Vol. 33, No. 2, p. As predicted by (50-59), the crystal structure of the first unit layer becomes a cubic crystal type, and the first unit layer has a high hardness to improve wear resistance. Therefore, the surface-coated cutting tool including the first unit layer can achieve a long life.

(Iii) The second unit layer is made of a nitride containing V and Al. The layer containing V, Al and N has an excellent balance between wear resistance, oxidation resistance and toughness. Therefore, the surface-coated cutting tool including the second unit layer can achieve a long life.

(Iv) The first unit layer and the second unit layer do not contain chromium (Cr) or titanium (Ti) contained in the conventional coating layer. Therefore, when processing a difficult-to-cut material containing Cr or Ti, the elements in the work material and the elements in the coating layer do not diffuse into each other, so that damage to the coating layer does not progress. Therefore, the surface-coated cutting tool including the first unit layer and the second unit layer can achieve a long life.

(V) The ratio of the number of Al atoms when the total number of metal atoms constituting the second unit layer is 1 is 0.40 or more and 0.75 or less. In this case, the crystal structure of the second unit layer is cubic, and the hardness is increased to improve the wear resistance. Therefore, the surface-coated cutting tool including the second unit layer can achieve a long life.

(Vi) When a layer made of a nitride containing Al and Zr is compared with a layer made of a nitride containing V and Al, the layer made of a nitride containing Al and Zr has a large compressive residual stress and a low hardness. , And a layer made of a nitride containing V and Al tends to have characteristics of low compressive residual stress and high hardness. Since the alternating layer includes a first unit layer made of a nitride containing Al and Zr and a second unit layer made of a nitride containing V and Al alternately stacked, the hardness of the first unit layer is low. This characteristic is complemented by the second unit layer having a high hardness, and the characteristic that the compressive residual stress of the second unit layer is small is complemented by the first unit layer having a large compressive residual stress. Therefore, it is considered that the hardness and the compressive residual stress of the alternating layer as a whole are improved in a well-balanced manner, and the life of the surface-coated cutting tool is prolonged.

(Vii) The alternating layers are formed by alternately stacking the first unit layers and the second unit layers, and the composition and the crystal lattice are discontinuous at the interface between the unit layers. When cracks occur from the surface layer of the coating layer during the cutting step, the development of cracks at the interface can be suppressed. Therefore, the life of the surface-coated cutting tool is considered to be longer.

The first unit layer is made of a nitride containing Al and Zr. The first unit layer does not include Ti and Cr. Examples of the nitride containing Al and Zr include ZrAlN, ZrAlSiN, ZrAlBN, ZrAlVN, ZrAlVSiN, and ZrAlVBN. As described above, the nitride containing Al and Zr is a nitride containing Al and Zr as constituent elements.

Conventionally, when a layer containing Zr is formed using a physical vapor deposition method, it has been difficult to maintain discharge because of the high melting point of Zr, and it has been difficult to form a film stably. In the surface-coated cutting tool of the present embodiment, since the first unit layer contains Al having a low melting point together with Zr, the melting point of the entire first unit layer is lowered. Therefore, when the first unit layer is formed by using the physical vapor deposition method, it is easy to maintain the discharge, and the film can be stably formed.

Also, since Zr is expensive, it was disadvantageous in terms of cost to mix it with the coating layer of the surface-coated cutting tool. In the coating layer of the surface-coated cutting tool of the present embodiment, the first unit layer containing Zr and the second unit layer not containing Zr are alternately laminated, so that the coating layer is formed of a single layer containing Zr. As compared with the case, the content of Zr in the coating layer can be reduced. Therefore, it is advantageous also in cost. In addition, since Zr is not included in difficult-to-cut materials such as Inconel and titanium alloy, Zr in the first unit layer interdiffuses with components in the work material during processing, and damage to the coating layer is accelerated. There is no.

比 The ratio of the number of Zr atoms when the total number of metal atoms constituting the first unit layer is 1 is 0.65 or more and 0.95 or less. In this case, the crystal structure of the first unit layer becomes a cubic type, and the first unit layer has a high hardness, thereby improving wear resistance. If the ratio of the number of atoms of Zr is less than 0.65, a part of the crystal structure becomes hexagonal, so that the hardness of the first unit layer may be reduced and the wear resistance may be reduced. On the other hand, when the ratio of the number of atoms of Zr is larger than 0.95, the effect of improving the hardness by adding Al cannot be obtained, and the hardness of the first unit layer decreases. From the viewpoint of increasing the hardness of the first unit layer, the ratio of the number of Zr atoms is preferably 0.7 or more and 0.85 or less, and more preferably 0.7 or more and 0.8 or less.

The second unit layer is made of a nitride containing V and Al. The first unit layer does not include Ti and Cr. Examples of the nitride containing V and Al include AlVN, AlVSiN, and AlVBN. Thus, the nitride containing V and Al is a nitride containing V and Al as constituent elements.

The layer containing ΔV, Al and N has an excellent balance between wear resistance, oxidation resistance and toughness. Therefore, the second unit layer contributes to extending the life of the surface-coated cutting tool.

Conventionally, since V is expensive, vanadium nitride (VN) has never been selected as the material of the coating layer of the surface-coated cutting tool. In the second unit layer of the present embodiment, the amount of V in the second unit layer can be reduced by dissolving AlN in VN to form a nitride containing V and Al. Therefore, it is advantageous also in cost.

比 The ratio of the number of Al atoms when the total number of metal atoms constituting the second unit layer is 1 is 0.40 or more and 0.75 or less. In this case, the crystal structure of the second unit layer is cubic, and the hardness is increased to improve the wear resistance. If the ratio of the number of Al atoms exceeds 0.75, a part of the crystal structure becomes hexagonal, so that the hardness of the second unit layer may be reduced and the wear resistance may be reduced. On the other hand, if the ratio of the number of atoms of Al is less than 0.40, the effect of improving the hardness by adding Al cannot be obtained, and the hardness of the second unit layer decreases. From the viewpoint of increasing the hardness of the second unit layer, the ratio of the number of atoms of Al is preferably from 0.55 to 0.70, more preferably from 0.6 to 0.65.

The first unit layer may include silicon (Si). When the first unit layer contains Si, the ratio of the number of silicon atoms when the total number of metal atoms constituting the first unit layer is 1 in the first unit layer is greater than 0 and 0.20 or less. Is preferred.

The second unit layer can include silicon (Si). When the second unit layer contains Si, in the second unit layer, the ratio of the number of silicon atoms when the total number of metal atoms constituting the second unit layer is 1 is greater than 0 and equal to or less than 0.20. Is preferred.

When the first unit layer and / or the second unit layer contains Si in the above amount, the mechanism is not clear, but the structure of the layer containing Si is finer and the hardness is further increased, and the hardness of the entire coating layer is increased. At the same time, oxidation resistance is improved.

において In the first unit layer and / or the second unit layer, when the ratio of the number of atoms of Si exceeds 0.20, the layer containing Si becomes brittle, and abrasion tends to be accelerated. When an alloy target serving as a metal raw material of a layer containing Si is produced by hot isostatic pressure treatment, the alloy target is broken during firing, and can be used for forming the first unit layer or the second unit layer. It tends to be difficult to obtain a high material strength.

From the viewpoint of increasing the hardness of the first unit layer and / or the second unit layer and improving the strength of the alloy target, the number of Si atoms in the first unit layer and / or the second unit layer is reduced. The ratio is more preferably 0.01 or more and 0.15 or less.

The first unit layer may contain boron (B). When the first unit layer contains B, the ratio of the number of boron atoms when the total number of metal atoms constituting the first unit layer is 1 in the first unit layer is more than 0 and 0.10 or less. Is preferred.

The second unit layer may contain boron (B). When the second unit layer contains B, in the second unit layer, the ratio of the number of boron atoms when the total number of metal atoms constituting the second unit layer is 1 is greater than 0 and equal to or less than 0.10. Is preferred.

場合 When the first unit layer and / or the second unit layer contains B in the above amount, the mechanism is not clear, but the hardness of the layer containing B is further increased, and the hardness of the entire coating layer is increased. Further, the oxide of B formed by surface oxidation during cutting densifies the oxide of Al in the layer, and the oxidation resistance is improved. Further, since the oxide of B has a low melting point, it acts as a lubricant at the time of cutting, and can suppress adhesion of a work material.

From the viewpoint of further improving the hardness and the oxidation resistance of the first unit layer and / or the second unit layer, the ratio of the number of B atoms in the first unit layer and / or the second unit layer is 0.01 or more and 0 or more. .10 or less is more preferable.

The first unit layer may include vanadium (V). When the first unit layer contains V, the ratio of the number of vanadium atoms when the total number of metal atoms constituting the first unit layer is 1 is preferably larger than 0 and 0.30 or less.

In this case, even if the surface of the first unit layer is oxidized in a high-temperature environment during cutting, the oxide of V has a low melting point and thus acts as a lubricant during cutting, thereby suppressing adhesion of the work material.

If the ratio of the number of atoms of ΔV exceeds 0.30, the hardness of the layer containing V tends to decrease. From the viewpoint of suppressing the adhesion of the work material and increasing the hardness of the layer containing V, in the first unit layer, the ratio of the number of atoms of V is more than 0 and less than 0.15. More preferred.

The first unit layer and the second unit layer may contain unavoidable impurities other than Al, Zr, V and N. Inevitable impurities include, for example, oxygen and carbon. The content of the entire unavoidable impurities in each of the first unit layer and the second unit layer is preferably greater than 0 atomic% and less than 1 atomic%. In this specification, “atomic%” means the ratio (%) of the number of atoms to the total number of atoms constituting a layer. The ratio (%) of the number of atoms to the total number of atoms constituting the layer can be measured using the above-described XPS analysis.

The first unit layer and the second unit layer each preferably have a thickness of 0.002 μm or more and 0.2 μm or less. According to this, the development of cracks generated on the surface of the coating layer can be suppressed. If the thickness of each of the first unit layer and the second unit layer is less than 0.002 μm, the effect of mixing the layers and alternately stacking the first unit layer and the second unit layer is obtained. Tend not to be able to. On the other hand, when the thickness of each of the first unit layer and the second unit layer exceeds 0.2 μm, the effect of suppressing the progress of cracks tends to be hardly obtained. The thickness of each of the first unit layer and the second unit layer is more preferably 0.005 μm or more and 0.15 μm or less.

As shown in FIG. 5, when the thickness of the first unit layer in the alternate layer is λ1 and the thickness of the second unit layer is λ2, in the adjacent first unit layer and second unit layer in the alternate layer, The ratio λ2 / λ1 of the thickness λ2 of the second unit layer to the thickness λ1 of the first unit layer is preferably 1 or more and 5 or less.

In addition to having high oxidation resistance, the second unit layer has a low thermal conductivity and has a property that it is difficult to transmit heat generated during cutting to the base material. When the proportion of the second unit layer in the coating layer is relatively increased, the total amount of Al in the coating layer is increased, so that the thermal insulation of the entire surface-coated cutting tool is improved. The wear resistance of the tool is improved. When λ2 / λ1 is less than 1, the toughness of the coating layer tends to decrease. On the other hand, when λ2 / λ1 exceeds 5, the effect of suppressing the development of cracks due to the lamination of the first unit layer and the second unit layer tends to be hardly obtained. From the viewpoint of the balance of these characteristics, it is more preferable that λ2 / λ1 is 1 or more and less than 3.

において In the alternate layers, the lower limit of the number of layers of each of the first unit layer and the second unit layer, that is, the lower limit of the number of repetitions of the first unit layer and the second unit layer is 2. In the alternating layers, the number of layers of each of the first unit layer and the second unit layer is preferably 10 or more and 500 or less, more preferably 100 or more and 400 or less. According to this, by laminating the first unit layer and the second unit layer, it is possible to sufficiently obtain the effect of improving the hardness and the compressive residual stress in a well-balanced manner.

全体 The total thickness of the alternating layers is preferably 0.8 μm or more and 15 μm or less, more preferably 2 μm or more and 7 μm or less. When the thickness is less than 0.8 μm, there is a tendency that the wear resistance cannot be sufficiently exerted in continuous working, and when it exceeds 15 μm, the chipping resistance tends to be unstable in intermittent cutting.

The fact that the first unit layer and the second unit layer are alternately stacked to form a multilayer structure in the alternate layer means that the cross section of the coating layer is observed with a TEM (transmission electron microscope) and the contrast difference is observed. It can be confirmed as showing a multilayer structure.

The thickness of the first unit layer, the thickness of the second unit layer, the number of laminations of the first unit layer and the second unit layer, and the thickness of the alternating layer are determined by using a TEM (transmission electron microscope) for the cross section of the coating layer. It can be measured by observation. Specifically, it can be measured by irradiating an electron beam to a sliced sample, imaging electrons transmitted or scattered through the sample, and observing the image at high magnification. The thickness is measured at arbitrarily selected three places, and the average value is defined as “thickness”. In this specification, when measuring the thickness of another layer using a TEM, the thickness is measured by the same method. Note that as long as the applicant has measured, as long as the measurement is performed on the same sample, even if the thickness measurement result is calculated a plurality of times by changing the selected part of the measurement visual field, there is almost no variation in the measurement result, and It was confirmed that setting the measurement field of view did not become arbitrary.

<Underlayer>
As shown in FIGS. 3 and 4, the coating layers 33 and 43 are provided between the base material 2 and the alternating layers 13 ′ and 13 in order to increase the adhesion between the base material 2 and the coating layers 33 and 43. An underlying layer 16 can be included. It is preferable that the element constituting the underlayer be the same as the element constituting the first unit layer or the second unit layer. For example, in FIG. 3, the elements forming the underlayer 16 are the same as the elements forming the first unit layer 12. In FIG. 4, the elements constituting the base layer 16 are the same as the elements constituting the second unit layer 15.

(4) Conventionally, a layer made of TiN has been formed as an underlayer in order to enhance the adhesion between the base material and the coating layer. In this case, in the manufacturing process, it is necessary to prepare an element (Ti) for forming the underlayer in addition to the element for forming the coating layer. In the present embodiment, since the elements constituting the underlayer are the same as the elements constituting the first unit layer or the second unit layer, the element for forming the underlayer is formed in the manufacturing process by forming the coating layer. It is not necessary to prepare separately from the element for this, and productivity improves.

The atomic ratio of the elements constituting the underlayer may be the same as or different from the atomic ratio of the elements constituting the first unit layer or the second unit layer, but from the viewpoint of productivity, they are the same. Preferably, there is. That is, the underlayer 16 preferably has the same composition as the first unit layer 12 or the second unit layer 15.

と The underlayer having the same composition as the first unit layer means that the underlayer has the same composition as the first unit layer included in the alternating layer. In this case, the underlayer is made of a nitride containing Al and Zr, and the ratio of the number of Zr atoms when the total number of metal atoms constituting the underlayer is 1 is 0.65 or more and 0.95 or less.

(4) When the base layer has the same composition as the first unit layer, even if the base material is exposed during the cutting, the oxidation from the interface between the base material and the coating layer can be suppressed.

下地 The underlayer having the same composition as the first unit layer may contain Si, B or V, and the content thereof may be the same as that of the first unit layer. In particular, when the underlayer contains Si, the ratio of the number of Si atoms when the total number of metal atoms constituting the underlayer is 1 is preferably larger than 0 and 0.10 or less. According to this, the hardness of the underlayer increases, and the crystal structure becomes finer, so that the wear resistance is improved.

{Examples of the underlayer having the same composition as the first unit layer include ZrAlN, ZrAlSiN, ZrAlBN, ZrAlVN, ZrAlVSiN, and ZrAlVBN.

(4) When the underlayer has the same composition as the first unit layer, the thickness of the underlayer is larger than the thickness of each first unit layer. For example, the thickness of the underlayer is preferably 0.1 μm or more. When the thickness of the underlayer is less than 0.1 μm, the effect of suppressing the oxidation from the interface between the base material and the coating layer by making the underlayer the same composition as the first unit layer tends not to be obtained. . On the other hand, the upper limit of the thickness of the underlayer is not particularly limited, but if it exceeds 2 μm, the above-described effect of suppressing the oxidation tends to be unable to be further improved. Therefore, considering the cost, the thickness of the underlayer is preferably 2 μm or less. The thickness of the underlayer is preferably from 0.2 μm to 1 μm, more preferably from 0.3 μm to 0.8 μm. The thickness of the underlayer is measured using SEM or TEM.

と The underlayer having the same composition as the second unit layer means that the underlayer has the same composition as the second unit layer included in the alternate layer. In this case, the underlayer is made of a nitride containing V and Al, and the ratio of the number of Al atoms is 0.40 or more and 0.75 or less when the total number of metal atoms constituting the underlayer is 1.

When the underlayer has the same composition as the second unit layer, the second unit layer tends to have a small stress. Therefore, in the case of intermittent processing such as milling or end milling in which a load is repeatedly applied to the cutting edge, the coating layer is formed. Is significantly improved in peeling resistance. From the viewpoint of improving the peeling resistance, the ratio of the number of Al atoms when the total number of metal atoms constituting the underlayer is 1 is preferably larger than 0.50 and 0.65 or less.

下地 The underlayer having the same composition as the second unit layer may include Si and B, and the contents thereof may be the same as those of the second unit layer.

下地 As the underlayer having the same composition as the second unit layer, for example, AlVN, AlVSiN, and AlVBN can be mentioned.

場合 When the underlayer has the same composition as the second unit layer, the thickness of the underlayer is larger than the thickness of each second unit layer. For example, the thickness of the underlayer is preferably 0.1 μm or more. If the thickness of the underlayer is less than 0.1 μm, there is a tendency that the effect of improving the peeling resistance cannot be obtained by making the underlayer the same composition as the second unit layer. On the other hand, the upper limit of the thickness of the underlayer is not particularly limited, but if it exceeds 2 μm, further improvement in the above-described peeling resistance tends not to be recognized. Therefore, considering the cost, the thickness of the underlayer is preferably 2 μm or less. The thickness of the underlayer is preferably from 0.2 μm to 1 μm, more preferably from 0.3 μm to 0.8 μm. The thickness of the underlayer is measured using SEM or TEM.

<Surface layer>
The coating layers 3, 23, 33, 43 are provided on the surface side of the alternating layers 13, 13 'in order to reduce the friction coefficient of the coating layers 3, 23, 33, 43 and extend the life of the surface-coated cutting tool. A surface layer 14 may be included. The surface layer is made of carbonitride (compound containing carbon and nitrogen) containing vanadium (V) and aluminum (Al), and the ratio of the number of Al atoms when the total number of metal atoms constituting the surface layer is set to 1 Is preferably 0.40 or more and 0.75 or less.

Generally, carbonitrides tend to have a lower coefficient of friction for work materials than nitrides. It is considered that such a decrease in the coefficient of friction is due to the contribution of carbon atoms. When the coating layer includes the surface layer, the coefficient of friction of the coating layer with respect to the workpiece is reduced, and the life of the surface-coated cutting tool is prolonged.

炭 Carbonitrides containing V and Al have excellent oxidation resistance. The surface of the surface layer has the highest temperature during cutting compared to the surface of the other layers. However, since the surface layer of this embodiment has excellent oxidation resistance, the life of the surface-coated cutting tool is prolonged. From the viewpoint of improving the oxidation resistance, the ratio of the number of Al atoms when the total number of metal atoms constituting the surface layer is 1 is more preferably more than 0.40 and 0.75 or less, and more preferably 0.50 or more and 0 or less. .60 or less is more preferable.

(4) By adjusting the composition ratio of N and C in the surface layer, it is possible to impart a predetermined color. This makes it possible to impart designability and distinctiveness to the appearance of the surface-coated cutting tool, which is commercially useful.

The surface layer may contain Si, and the ratio of the number of Si atoms when the total number of metal atoms constituting the surface layer is 1 is preferably more than 0 and 0.20 or less, more preferably 0.05 or more and 0.15 or less. The following is more preferred. According to this, the hardness of the surface layer is increased, and the oxidation resistance is improved.

The surface layer may contain B, and the ratio of the number of B atoms to the total number of metal atoms constituting the surface layer is preferably greater than 0 and less than 0.10, more preferably greater than 0 and less than 0.05. The following is more preferred. According to this, the hardness of the surface layer increases. Further, the oxide of B formed by surface oxidation during cutting tends to densify the oxide of Al in the layer, and the oxidation resistance is improved.

The surface layer can contain V. When the total number of metal atoms constituting the surface layer is set to 1, the ratio of the number of V atoms is preferably greater than 0 and 0.30 or less, more preferably greater than 0 and 0.15 or less. Less than is more preferable. According to this, the adhesion resistance of the surface layer is improved.

Examples of the surface layer include AlVCN, AlVSiCN, and AlVBCN. Thus, a carbonitride containing V and Al is a carbonitride containing V and Al as constituent elements.

The thickness of the surface layer is preferably 0.1 μm or more. If the thickness of the surface layer is less than 0.1 μm, the effect of imparting lubricity by the surface layer may not be easily obtained. On the other hand, the upper limit of the thickness of the surface layer is not particularly limited, but if it exceeds 2 μm, the effect of imparting lubricity tends to be unable to be further improved. Therefore, in consideration of cost, the thickness of the surface layer is preferably 2 μm or less. The thickness of the surface layer is measured using a TEM.

<Other layers>
The coating layers 3, 23, 33, 43 may include other layers in addition to the alternating layers 13, 13 ', the underlayer 16, and the surface layer 14. As another layer, for example, an intermediate layer or an alumina layer may be included between the alternating layer and the surface layer.

[Embodiment 2: Manufacturing method of surface-coated cutting tool]
The method for manufacturing a surface-coated cutting tool according to the first embodiment includes a step of preparing a base material and a step of forming a coating layer on the base material. The step of forming the covering layer includes a step of forming alternate layers by alternately stacking the first unit layers and the second unit layers using a physical vapor deposition method.

<Process of preparing base material>
As the substrate, the substrate described in Embodiment 1 is prepared.

<Step of forming coating layer>
Next, a coating layer is formed on the substrate. The step of forming the coating layer includes a step of forming the alternating layers by alternately stacking the first unit layers and the second unit layers using a physical vapor deposition method (PVD method).

層 In order to improve the wear resistance of the coating layer including the alternating layers, it is preferable to form a layer made of a highly crystalline compound. Applicants have studied various methods for forming the alternating layers and have found that it is preferable to use a physical vapor deposition method. Note that a base layer can be formed directly above the base material in order to increase the adhesion between the base material and the coating layer.

As the physical vapor deposition method, at least one selected from the group consisting of a cathode arc ion plating method, a balanced magnetron sputtering method, an unbalanced magnetron sputtering method, and a HiPIMS method can be used. In particular, it is preferable to use a cathode arc ion plating method having a high ionization rate of a raw material element. In the case where the cathode arc ion plating method is used, before forming the alternating layer, the surface of the base material can be subjected to ion bombardment treatment of the metal, so that the base material and the coating layer including the alternating layer can be used. The adhesion of is greatly improved.

In the cathode arc ion plating method, for example, after setting a base material in a device and setting a target as a cathode, a high voltage is applied to the target to cause an arc discharge to ionize atoms constituting the target. Evaporation to deposit the substance on the substrate.

In the balanced magnetron sputtering method, for example, a target is set on a magnetron electrode provided with a magnet that forms a balanced magnetic field while a base material is installed in an apparatus, and high-frequency power is applied between the magnetron electrode and the base material. Then, gas plasma is generated, and ions of the gas generated by the generation of the gas plasma collide with a target to deposit atoms released from the target on a base material.

The unbalanced magnetron sputtering method can be performed, for example, by making the magnetic field generated by the magnetron electrode in the above-mentioned balanced magnetron sputtering method non-equilibrium. Further, a HiPIMS method in which a high voltage can be applied and a dense film can be obtained can be used.

Note that another layer such as an intermediate layer, an alumina layer, and a surface layer can be formed on the alternate layer. These other layers can be formed by a conventionally known chemical vapor deposition method or physical vapor deposition method. From the viewpoint that another layer can be formed continuously with the first unit layer and the second unit layer in one physical vapor deposition apparatus, the other layer is preferably formed by a physical vapor deposition method.

<Production of surface coated cutting tool>
[Sample 1 to Sample 23]
(1) Preparation of Base Material FIG. 6 is a schematic cross-sectional view of the cathode arc ion plating apparatus used in this example, and FIG. 7 is a schematic top view of the apparatus of FIG.

In the apparatus shown in FIGS. 6 and 7, a cathode 106 for the first unit layer, a cathode 107 for the second unit layer, and a cathode 120 for the surface layer, which are alloy targets serving as metal materials for the coating layer, are placed in the chamber 101. And a rotatable substrate holder 104 for installing the substrate 2. An arc power supply 108 is attached to the cathode 106, and an arc power supply 109 is attached to the cathode 107. Further, a bias power supply 110 is attached to the substrate holder 104. The chamber 101 has a gas inlet through which a gas 105 is introduced, and a gas outlet 103 for adjusting the pressure in the chamber 101. The structure is such that the gas in 101 can be sucked.

(4) A chip having a grade of JIS standard P30 cemented carbide and a shape of JIS standard CNMG120408 and SEMT13T3AGSN manufactured by Sumitomo Electric Hardmetal Corporation was mounted on the base material holder 104.

Next, the inside of the chamber 101 is depressurized by a vacuum pump, and the temperature is heated to 500 ° C. by a heater installed in the apparatus while rotating the substrate 2 so that the pressure in the chamber 101 becomes 1.0 × 10 ^-4 Vacuuming was performed until Pa was reached. Next, argon gas was introduced from the gas inlet to maintain the pressure in the chamber 101 at 3.0 Pa, and the voltage of the bias power supply 110 was gradually increased to −1000 V while cleaning the surface of the substrate 2 for 15 minutes. Done. Thereafter, the substrate was washed by exhausting argon gas from the inside of the chamber 101 (argon bombardment treatment).

(2) Formation of Coating Layer Next, with the substrate 2 rotated at the center, while introducing nitrogen as a reaction gas, the temperature of the substrate 2 was set to 500 ° C., the reaction gas pressure was set to 2.0 Pa, and a bias power While maintaining the voltage of 110 at a certain value in the range of −50 V to −200 V, an arc current of 100 A is supplied to each of the

cathodes

106 and 107 to generate metal ions from the

cathodes

106 and 107, Underlayers and alternating layers having the compositions shown in Table 1 above were formed. The composition of the cathode 106 is adjusted so that the ratio of Zr, Al, Si, B, and V is the same as the composition ratio of the first unit layer in Table 1. The composition of the cathode 107 is adjusted so that the ratio of Ti, Al, V, Si, and B is the same as the ratio of the composition of the second unit layer in Table 1.

(4) The alternate layer was formed by alternately stacking the first unit layer and the second unit layer one by one on the underlayer, each having the number of layers shown in Table 1. The thickness of the underlayer, the thickness of each of the first unit layer and the second unit layer in the alternate layer, and the number of layers were adjusted by the rotation speed of the base material. The current supplied to the evaporation source was stopped when the thickness of the underlayer and the number of stacked first unit layers and second unit layers reached the values shown in Table 1.

Next, while introducing nitrogen and methane gas as reaction gases into the chamber 101, the cathode 120 is maintained while the temperature of the substrate 2 is maintained at 400 ° C., the reaction gas pressure is maintained at 2.0 Pa, and the voltage of the bias power supply 110 is maintained at −350V. By supplying an arc current of 100 A to the cathode, metal ions were generated from the cathode 120 to form a surface layer on the alternating layers. When the thickness of the surface layer reached the thickness shown in Table 1, the current supplied to the evaporation source was stopped. The composition of the cathode 120 was adjusted so that the ratio of Al, V, Si, B, and V was the same as the composition ratio of the surface layer in Table 1. The ratio of nitrogen to carbon in the composition of the surface layer was adjusted by the ratio of the amount of nitrogen introduced and the amount of methane gas introduced. As a result, cutting edge-exchange type cutting tips of Samples 1 to 3, 6 to 13, 15, 16, 19, 20, 22, and 23 were produced.

In Samples 4 and 5, first unit layers and second unit layers having the composition shown in Table 1 were alternately formed on the same base material as Sample 1, and a surface layer was further formed. Without forming, a cutting edge replaceable cutting tip was made.

In the sample 14, the first unit layer and the second unit layer having the composition shown in Table 1 were alternately formed on the same base material as the sample 1, and the cutting edge was changed without forming the base layer and the surface layer. Die cutting tips were made.

In sample 17, the second unit layer having the composition shown in Table 1 was formed on the same substrate as sample 1, and the underlayer, the first unit layer, and the surface layer were not formed. A chip was made.

In Samples 18 and 21, the underlayer having the composition shown in Table 1 and the first unit layer and the second unit layer were alternately formed on the same base material as Sample 1, and the surface layer was formed. Instead, a cutting edge replaceable cutting tip was produced.

組成 The compositions of the underlayer, the first unit layer, the second unit layer, and the surface layer in Table 1 were measured using XPS (X-ray photoelectron spectroscopy).

「" One layer thickness "in Table 1 means the thickness of each of the first unit layer and the second unit layer constituting the alternating layer. “Thickness” in Table 1 means the total thickness of each of the underlayer, the first unit layer, the second unit layer, the surface layer, and the coating layer. "One layer thickness" and "thickness" are values measured using TEM and SEM, respectively.

「" Lamination number "in Table 1 means the number of each of the first unit layer and the second unit layer in the alternating layers.

「“ The hardness of the entire coating layer ”in Table 1 is a value confirmed by a nano indenter (Nano Indenter XP manufactured by MTS).

The “compressive residual stress of the entire coating layer” in Table 1 was measured using a sin ² ψ method (“X-ray stress measurement method” (issued by Japan Society for Materials Science, 1981, Yokendo Co., Ltd.)) using an X-ray residual stress measurement device. (See pages 54-66) in absolute terms.

"Crystallinity of the entire coating layer" in Table 1 was analyzed by an X-ray diffractometer.
<Life evaluation of surface coated cutting tools>
(Turning test)
For each of the cutting edge-changeable cutting inserts of the CNMG120408 shape of Samples 1 to 23, a wet continuous turning test and an intermittent turning test were performed on the alloy steel (SCM440) and the difficult-to-cut material (Inconel 718) under the conditions shown in Table 2. The time until the flank wear of the cutting edge became 0.2 mm was measured. Table 3 shows the results. In Table 3, it is shown that the longer the cutting time is, the longer the life is.

Samples 1 to 14 and Samples 21 to 23 correspond to Examples, and Samples 15 to 20 correspond to Comparative Examples. Sample 1 to Sample 14 and Sample 21 to Sample 23 are different from Samples 15 to 20 in the continuous turning test and the intermittent turning test in the high-speed and high-efficiency machining of difficult-to-cut materials. It was confirmed that the life was prolonged.

(Milling test)
For each of the SEMT13T3AGSN-shaped replaceable cutting inserts of Samples 1 to 23, align the center line of a 150 mm wide plate made of a difficult-to-cut material with the center of a wider φ160 mm cutter to perform surface milling. The milling test was performed under the conditions of a dry milling test shown in Table 4, and the cutting length until the flank wear of the cutting edge became 0.2 mm was measured. Table 5 shows the results. In Table 5, it is shown that the longer the cutting length is, the longer the life is.

Samples 1 to 14 and Samples 21 to 23 correspond to Examples, and Samples 15 to 20 correspond to Comparative Examples. The cutting length of the cutting edge of Samples 1 to 14, and Samples 21 to 23 is greatly increased compared to Samples 15 to 20, and even when milling difficult-to-cut materials at high speed and high efficiency and under dry conditions. It has been confirmed that the life of the cutting edge-exchange type cutting tip is prolonged.

Although the embodiments and examples of the present invention have been described above, it is originally planned that the configurations of the above-described embodiments and examples are appropriately combined and variously modified.

形態 The embodiments and examples disclosed this time are examples in all respects, and should not be construed as limiting. The scope of the present invention is defined by the terms of the claims, rather than the embodiments and examples, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1, 21, 31, 41 {surface coated cutting tool, 2} substrate, 3, 23, 33, 43} coated layer, 12} first unit layer, 13, 13 'alternate layer, 14} surface layer, 15 # second unit layer, 16 Underlayer.

Claims

A substrate, a surface-coated cutting tool including a coating layer for coating the substrate,
The coating layer includes an alternating layer in which first unit layers and second unit layers are alternately stacked,
The first unit layer is made of a nitride containing aluminum and zirconium,
In the first unit layer, a ratio of the number of zirconium atoms is 0.65 or more and 0.95 or less when the total number of metal atoms constituting the first unit layer is 1.
The second unit layer is made of a nitride containing vanadium and aluminum,
A surface-coated cutting tool, wherein, in the second unit layer, the ratio of the number of aluminum atoms is 0.40 or more and 0.75 or less when the total number of metal atoms constituting the second unit layer is 1.
The ratio λ2 / λ1 of the thickness λ2 of the second unit layer to the thickness λ1 of the first unit layer in the adjacent first unit layer and the second unit layer in the alternate layer is 1 or more and 5 or less. The surface-coated cutting tool according to claim 1.
The first unit layer includes silicon,
The ratio of the number of silicon atoms when the total number of metal atoms constituting the first unit layer is set to 1 in the first unit layer is greater than 0 and 0.20 or less. 3. The surface-coated cutting tool according to 2.
The second unit layer contains silicon,
2. The ratio of the number of silicon atoms when the total number of metal atoms constituting the second unit layer is 1 in the second unit layer is greater than 0 and 0.20 or less. 3. 4. The surface-coated cutting tool according to any one of 3.
The first unit layer contains boron,
The ratio of the number of boron atoms when the total number of metal atoms constituting the first unit layer is set to 1 in the first unit layer is greater than 0 and equal to or less than 0.10. 5. The surface-coated cutting tool according to any one of 4.
The second unit layer contains boron,
The ratio of the number of boron atoms when the total number of metal atoms constituting the second unit layer is set to 1 in the second unit layer is more than 0 and 0.10 or less. The surface-coated cutting tool according to any one of items 5 to 5.
The first unit layer includes vanadium,
2. The ratio of the number of vanadium atoms in the first unit layer when the total number of metal atoms constituting the first unit layer is 1 is greater than 0 and equal to or less than 0.30. 3. 7. The surface-coated cutting tool according to any one of 6.
8. The surface-coated cutting tool according to claim 1, wherein each of the first unit layer and the second unit layer has a thickness of 0.002 μm or more and 0.2 μm or less. 9.
The coating layer includes a base layer disposed between the substrate and the alternating layer,
The surface-coated cutting tool according to any one of claims 1 to 8, wherein the underlayer has the same composition as the first unit layer or the second unit layer.
The surface-coated cutting tool according to claim 9, wherein the thickness of the underlayer is 0.1 μm or more and 2 μm or less.
The coating layer includes a surface layer disposed on a surface side of the alternating layer,
The surface layer is made of carbonitride containing vanadium and aluminum,
11. The surface layer according to claim 1, wherein a ratio of the number of aluminum atoms when the total number of metal atoms constituting the surface layer is 1 is 0.40 or more and 0.75 or less. 12. Item 2. A surface-coated cutting tool according to item 1.
A method for producing a surface-coated cutting tool according to any one of claims 1 to 11,
Preparing the substrate,
Forming the coating layer on the base material,
The step of forming the coating layer includes a step of forming the alternating layers by alternately laminating the first unit layers and the second unit layers using a physical vapor deposition method. Production method.