Coated Cutting Tools

Abstract

To provide a coated cutting tool which can extend a tool life in both high speed working and high feed working.SOLUTION: A coated cutting tool includes a base material, and a coating layer formed on the base material, wherein the coating layer has a first alternately laminated structure that two or more layers A and layers B are alternately formed, the layer A contains (AlaCrbTi1-a-b)N, the layer B contains (AlcTi1-c-dBd)N, average thickness of the first alternately laminated structure is 0.50 μm or more and 10.00 μm or less, and average thickness per one layer of each of the layers A and the layers B in the first alternately laminated structure is 2 nm or more and 300 nm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a coated cutting tool. [Background technology]

[0002] Conventionally, cutting tools made of cemented carbide or cubic boron nitride (cBN) sintered compacts have been widely used for cutting steel, etc. Among these, surface-coated cutting tools, which have one or more hard coatings such as TiN, TiAlN, or TiCrN layers on the surface of a cemented carbide substrate, are used in a variety of processes due to their versatility.

[0003] For example, Patent Document 1 discloses a surface-coated cutting tool including a tool substrate and a coating layer, wherein the coating layer has a thickness of 0.2 to 10.0 μm and includes a structure in which at least one first layer and one second layer are alternately laminated, and the at least one first layer has an average thickness of 0.5 to 100.0 nm and is represented by the formula: (Al x Ti 1-x-y-z M y )B z N (wherein M is one or more elements selected from Groups 4, 5, and 6 of the periodic table and the lanthanides, and x is 0.100 to 0.640, y is 0.001 to 0.100, and z is 0.060 to 0.400), and each of the at least one second layer has an average thickness of 0.5 to 100.0 nm and is represented by the formula: (Al p Cr 1-p-q-r M' q )B r A surface-coated cutting tool has been proposed, characterized by having an average composition represented by N (wherein M' is one or more elements selected from Groups 4, 5, and 6 of the periodic table and the lanthanides, and p is 0.650 to 0.900, q is 0.000 to 0.100, and r is 0.000 to 0.050).

[0004] Also, for example, in Patent Document 2, there is a coated cutting tool including a cemented carbide body and a PVD coating. The cemented carbide body has a composition containing 5 to 18 wt% Co, 0.1 to 2.5 wt% Cr, 0 to 10 wt% of carbides or carbonitrides (other than WC) of metals in Groups 4, 5, and 6 of the periodic table of elements, and the balance being WC. The PVD coating has an average composition of Ti a Al b Cr c N (a = 0.25 to 0.7, b = 0.3 to 0.7, and c = 0.01 to 0.2, a + b + c = 1), and is a (Ti, Al, Cr) N nano-layered PVD coating. The PVD coating is a nano-layered PVD coating A / B / A / B / A ···, where the sub-layer A is Ti u Al v Cr w N (u = 0.1 to 0.4, v = 0.5 to 0.8, w = 0.01 to 0.3, u + v + w = 1), the sub-layer B is Ti x Al y Cr z N (x = 0.4 to 0.7, y = 0.3 to 0.6, z = 0 to 0.2, x + y + z = 1, u < x and v > y) respectively, and the thickness of the nano-layered PVD coating is 0.5 to 10 μm. A coated cutting tool has been proposed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, there has been a strong demand for labor-saving, energy-saving, and cost-effective cutting processes, and as a result, coated cutting tools are being required to have performance that can withstand more efficient cutting.More efficient processing, for example, tends to require higher speeds and / or higher feed rates, but the performance required of coated cutting tools varies greatly under these conditions.

[0007] In high-speed machining, the materials used in coated cutting tools must be hard enough to improve wear resistance, and must also have improved thermal shock resistance at high temperatures and be able to prevent embrittlement due to material deterioration.On the other hand, in high-feed machining, the load on the tool cutting edge tends to increase, so the materials used in coated cutting tools must also have high toughness.

[0008] Since it is generally difficult to achieve both the properties required of a coated cutting tool in high-speed machining and high-feed machining, coated cutting tools suited to each type of machining are usually selected and used. On the other hand, achieving and enhancing both of these properties is preferable from the viewpoint of cost reduction, since one type of coated cutting tool can be used to handle a variety of machining conditions.

[0009] The surface-coated cutting tool of Patent Document 1 has a coating layer formed by alternating lamination of a first layer containing element B and a second layer that may not contain element B, and has excellent thermal shock resistance in high-speed machining. However, the surface-coated cutting tool of Patent Document 1 has insufficient thermal stability and toughness near the interface between the first and second layers in the coating layer, and there is room for further improvement. For the above reasons, the surface-coated cutting tool of Patent Document 1 has room for improvement in both fracture resistance in high-speed machining and fracture resistance in high-feed machining.

[0010] Furthermore, the coated cutting tool of Patent Document 2 has a coating layer in which sub-layers A and B are alternately laminated, resulting in excellent fracture resistance during high-feed machining. On the other hand, the coated cutting tool of Patent Document 2 does not contain element B, so the coating layer is insufficient in hardness, and since layers containing element B and layers not containing element B are not alternately laminated, the thermal shock resistance during high-speed machining is insufficient. For these reasons, the coated cutting tool of Patent Document 2 has room for improvement in terms of wear resistance and fracture resistance during high-speed machining.

[0011] The present invention has been made in view of the above circumstances, and has as its object to provide a coated cutting tool that can extend the tool life in both high-speed cutting and high-feed cutting. [Means for solving the problem]

[0012] The inventors of the present invention have conducted extensive research into extending the tool life of coated cutting tools and have discovered that if a coated cutting tool is given a specific configuration, the tool life can be extended in both high-speed machining and high-feed machining, which has led to the completion of the present invention.

[0013] That is, the gist of the present invention is as follows. [1] A coated cutting tool comprising a substrate and a coating layer formed on the substrate, the coating layer has a first alternating laminate structure in which two or more A layers and two or more B layers are alternately formed, The layer A contains a compound having a composition represented by the following formula (1): (Al a Cr b Ti 1-a-b )N (1) (In formula (1), a is the content ratio (atomic ratio) of Al element to the total of Al element, Cr element, and Ti element, 0.50≦a≦0.68 is satisfied, b is the content ratio (atomic ratio) of Cr element to the total of Al element, Cr element, and Ti element, 0.02≦b≦0.30 is satisfied, 1-ab is the content ratio (atomic ratio) of Ti element to the total of Al element, Cr element, and Ti element, 0.11≦1-ab≦0.40.) The layer B contains a compound having a composition represented by the following formula (2): (Al c Ti 1-c-d B d )N (2) (In formula (2), c is the content ratio (atomic ratio) of Al element to the total of Al element, Ti element, and B element, 0.30≦c≦0.64 is satisfied, d is the content ratio (atomic ratio) of the B element to the total of the Al element, the Ti element, and the B element, 0.01≦d≦0.10 is satisfied, 1-cd is the content ratio (atomic ratio) of Ti element to the total of Al element, Ti element, and B element, 0.30≦1-cd≦0.69 is satisfied.) The average thickness of the first alternating laminate structure is 0.50 μm or more and 10.00 μm or less, the average thickness per layer of the A layer in the first alternating laminate structure is 2 nm or more and 300 nm or less; the average thickness per layer of the B layer in the first alternating laminate structure is 2 nm or more and 300 nm or less; Coated cutting tools. [2] the ratio ((1-ab) / d) of the content ratio (atomic ratio) of Ti element in the A layer to the content ratio (atomic ratio) of B element in the B layer is 2.0 or more and 25.0 or less; [1] The coated cutting tool according to [1]. [3] the average value ((a+c) / 2) of the content ratio (atomic ratio) of Al element in the A layer and the content ratio (atomic ratio) of Al element in the B layer is 0.50 or more and 0.62 or less; [1] or [2]. [4] the coating layer further has a second alternating laminate structure in which the A layer and the C layer are alternately formed in two or more layers, The layer C contains a compound having a composition represented by the following formula (3): (Al e Ti 1-e )N (3) (In formula (3), e is the Al element. Basic and the content ratio (atomic ratio) of Al element to the total of Ti element, 0.30≦e≦0.64 is satisfied, 1-e is Al element Basic and the content ratio (atomic ratio) of Ti element to the total amount of Ti element, 0.36≦1-e≦0.70 is satisfied.) The average thickness of the second alternating laminate structure is 0.50 μm or more and 5.00 μm or less, the average thickness per layer of the A layer in the second alternate laminated structure is 2 nm or more and less than 30 nm, the average thickness per layer of the C layer in the second alternate laminated structure is 2 nm or more and less than 30 nm; The coated cutting tool according to any one of [1] to [3]. [5] the average thickness per layer of the A layer in the first alternate laminated structure is 30 nm or more and 300 nm or less; the average thickness per layer of the B layer in the first alternating laminate structure is 30 nm or more and 300 nm or less; The coated cutting tool according to any one of [1] to [4]. [6] the coating layer has a third alternating laminate structure in which the first alternating laminate structure and the second alternating laminate structure are alternately formed three or more times in total, an average thickness per structure of the first alternating laminate structure in the third alternating laminate structure is 0.1 μm or more and 1.5 μm or less; an average thickness per structure of the second alternating laminate structure in the third alternating laminate structure is 0.1 μm or more and 1.5 μm or less; [4] The coated cutting tool according to [4]. [7] In X-ray diffraction of the first alternate stacked structure, the ratio (I(111) / I(200)) of the diffraction peak intensity (I(111)) of the cubic (111) plane to the diffraction peak intensity (I(200)) of the cubic (200) plane is 0.5 or more and 5.0 or less. The coated cutting tool according to any one of [1] to [6]. [8] In X-ray diffraction of the third alternating stack structure, the ratio (I(111) / I(200)) of the diffraction peak intensity (I(111)) of the cubic (111) plane to the diffraction peak intensity (I(200)) of the cubic (200) plane is 0.5 or more and 5.0 or less. [6] A coated cutting tool according to [6]. [9] the coating layer has an upper layer on a surface of the first alternating laminate structure or the third alternating laminate structure opposite to the substrate, the upper layer is a single layer or multiple layers of a compound consisting of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y, and at least one element selected from the group consisting of C, N, O, and B (however, the composition of the compound constituting the upper layer is different from the composition of the compound constituting the layer of the first alternating laminate structure or the second alternating laminate structure that is in contact with the upper layer); The average thickness of the upper layer is 0.01 μm or more and 2.00 μm or less. The coated cutting tool according to any one of [1] to [8].

[10] the coating layer has a lower layer between the substrate and the first alternating laminate structure or the third alternating laminate structure, the lower layer is a single layer or multiple layers of a compound consisting of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y, and at least one element selected from the group consisting of C, N, O, and B (however, the composition of the compound constituting the lower layer is different from the composition of the compound constituting the layer of the first alternating laminate structure or the second alternating laminate structure that is in contact with the lower layer); The average thickness of the lower layer is 0.01 μm or more and 2.00 μm or less. The coated cutting tool according to any one of [1] to [9].

[11] The average thickness of the entire coating layer is 0.5 μm or more and 10.0 μm or less. The coated cutting tool according to any one of [1] to

[10] . [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a coated cutting tool that can extend the tool life in both high-speed cutting and high-feed cutting. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram showing an example of a coated cutting tool of the present invention. [Figure 2] FIG. 2 is a schematic view showing another example of a coated cutting tool of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail, but the present invention is not limited to the following embodiment. The present invention can be modified in various ways without departing from the gist of the invention. In the drawings, the same elements are given the same reference numerals, and redundant explanations will be omitted. Furthermore, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios of the drawings are not limited to those shown.

[0017] The coated cutting tool of the present embodiment is a coated cutting tool including a substrate and a coating layer formed on the substrate, the coating layer has a first alternating laminate structure in which two or more A layers and two or more B layers are alternately formed, Layer A contains a compound having a composition represented by the following formula (1): (Al a Cr b Ti 1-a-b )N (1) (In formula (1), a is the content ratio (atomic ratio) of Al element to the total of Al element, Cr element, and Ti element, 0.50≦a≦0.68 is satisfied, b is the content ratio (atomic ratio) of Cr element to the total of Al element, Cr element, and Ti element, 0.02≦b≦0.30 is satisfied, 1-ab is the content ratio (atomic ratio) of Ti element to the total of Al element, Cr element, and Ti element, 0.11≦1-ab≦0.40.) Layer B contains a compound having a composition represented by the following formula (2): (Al c Ti 1-c-d B d )N (2) (In formula (2), c is the content ratio (atomic ratio) of Al element to the total of Al element, Ti element, and B element, 0.30≦c≦0.64 is satisfied, d is the content ratio (atomic ratio) of the B element to the total of the Al element, the Ti element, and the B element, 0.01≦d≦0.10 is satisfied, 1-cd is the content ratio (atomic ratio) of Ti element to the total of Al element, Ti element, and B element, 0.30≦1-cd≦0.69 is satisfied.) The average thickness of the first alternating laminate structure is 0.50 μm or more and 10.00 μm or less, the average thickness per layer of the A layer in the first alternating laminate structure is 2 nm or more and 300 nm or less; The average thickness of each B layer in the first alternate laminate structure is 2 nm or more and 300 nm or less.

[0018] The factors that enable such coated cutting tools to have a long tool life in both high-speed cutting and high-feed cutting are not fully understood, but are presumed to be as follows, although the factors are not limited to the following. In the layer A forming the first alternating laminate structure, the composition represented by formula (1) (Al a Cr b Ti1-a-b When the content ratio a of Al element in N is 0.50 or more, the hardness and oxidation resistance are increased, and the coated cutting tool has excellent wear resistance in high-speed machining. On the other hand, when the content ratio a of Al element is 0.68 or less, the formation of hexagonal crystals is suppressed, thereby increasing the hardness and improving the wear resistance of the coated cutting tool in high-speed machining. In addition, the thermal stability near the interface between Layer A and Layer B is improved, resulting in improved thermal shock resistance and, further, improving the chipping resistance of the coated cutting tool in high-speed machining. In addition, in the layer A forming the first alternate laminate structure, the composition represented by formula (1) (Al a Cr b Ti 1-a-b When the Cr content ratio b in N is 0.02 or more, the formation of hexagonal crystals is suppressed, resulting in increased hardness and excellent wear resistance in high-speed machining of the coated cutting tool. Furthermore, the thermal stability near the interface between Layer A and Layer B is improved, resulting in improved thermal shock resistance and improved fracture resistance in high-speed machining of the coated cutting tool. On the other hand, when the Cr content ratio b is 0.30 or less, toughness is improved, resulting in improved fracture resistance in both high-speed and high-feed machining of the coated cutting tool. In addition, in the layer A forming the first alternate laminate structure, the composition represented by formula (1) (Al a Cr b Ti 1-a-b When the Ti content (1-ab) in N is 0.11 or more, the thermal stability of the interface between Layers A and B is improved, improving thermal shock resistance. Furthermore, peeling of the coating layer and the propagation of cracks into the substrate during cutting are suppressed, resulting in a coated cutting tool with excellent chipping resistance during high-speed machining. On the other hand, when the Ti content (1-ab) is 0.40 or less, if the Al content (a) is relatively large, the hardness increases and oxidation resistance improves, resulting in a coated cutting tool with excellent wear resistance during high-speed machining. Furthermore, if the Cr content (b) is relatively large, the formation of hexagonal crystals is suppressed, resulting in a high hardness and a coated cutting tool with excellent wear resistance during high-speed machining. Next, in the B layer forming the first alternate laminate structure, a composition represented by formula (2) (Al c Ti 1-c-d Bd When the content ratio of Al element in N, c, is 0.30 or more, the hardness and oxidation resistance are increased, and the coated cutting tool has excellent wear resistance in high-speed machining. On the other hand, when the content ratio of Al element, c, is 0.64 or less, the formation of hexagonal crystals is suppressed, thereby increasing the hardness and improving the wear resistance of the coated cutting tool in high-speed machining. In addition, the thermal stability near the interface between Layer A and Layer B is improved, resulting in improved thermal shock resistance, and further improving the chipping resistance of the coated cutting tool in high-speed machining. In addition, in the B layer forming the first alternate laminate structure, the composition represented by formula (2) (Al c Ti 1-c-d B d When the content ratio d of the B element in N is 0.01 or more, the hardness is increased and the coated cutting tool has excellent wear resistance in high-speed machining. On the other hand, when the content ratio d of the B element is 0.10 or less, the toughness is improved and the chipping resistance of the coated cutting tool in both high-speed machining and high-feed machining is improved. In addition, in the B layer forming the first alternate laminate structure, the composition represented by formula (2) (Al c Ti 1-c-d B d When the Ti content (1-cd) in N is 0.30 or more, the thermal stability of the interface between the A and B layers is improved, improving thermal shock resistance. Furthermore, peeling of the coating layer and the propagation of cracks into the substrate during cutting are suppressed, resulting in a coated cutting tool with excellent chipping resistance in high-speed machining. On the other hand, when the Ti content (1-cd) is 0.69 or less, if the Al content (c) is relatively large, the hardness increases and oxidation resistance improves, resulting in a coated cutting tool with excellent wear resistance in high-speed machining. Furthermore, if the B content (d) is relatively large, the hardness increases and the coated cutting tool with excellent wear resistance in high-speed machining. Furthermore, the coated cutting tool of this embodiment has a first alternating laminate structure in which two or more A layers and two or more B layers each containing a compound having such a specific composition are alternately formed, thereby improving thermal shock resistance and providing excellent chipping resistance during high-speed machining. Furthermore, when the average thickness of the first alternating laminate structure is 0.50 μm or more, the wear resistance of the coated cutting tool in high-speed machining is improved, while when the average thickness of the first alternating laminate structure is 10.00 μm or less, peeling of the coating layer can be suppressed, and the chipping resistance of the coated cutting tool in both high-speed machining and high-feed machining is improved. Furthermore, when the average thickness per layer of layers A and B in the first alternating laminate structure is 2 nm or more, the effect of suppressing the propagation of cracks generated during machining into the substrate is improved, and the fracture resistance of the coated cutting tool is improved in both high-speed and high-feed machining. On the other hand, when the average thickness per layer of layers A and B in the first alternating laminate structure is 300 nm or less, the effect of having an alternating laminate structure consisting of two different layers is obtained, the hardness is increased, and the coated cutting tool has excellent wear resistance in high-speed machining. Furthermore, the effect of suppressing the propagation of cracks generated during machining into the substrate is obtained, and the fracture resistance of the coated cutting tool is improved in both high-speed and high-feed machining. These effects combine to enable the coated cutting tool of this embodiment to extend the tool life in both high-speed machining and high-feed machining.

[0019] The coated cutting tool of this embodiment includes a substrate and a coating layer formed on the substrate surface. The substrate used in this embodiment is not particularly limited as long as it can be used as a substrate for a coated cutting tool. Examples of the substrate include cemented carbide, cermet, ceramics, cubic boron nitride sintered body, diamond sintered body, and high-speed steel. Among these, it is more preferable that the substrate is one or more selected from the group consisting of cemented carbide, cermet, ceramics, and cubic boron nitride sintered body, since the wear resistance and chipping resistance of the coated cutting tool are further improved.

[0020] In the coated cutting tool of this embodiment, the average thickness of the entire coating layer is preferably 0.5 μm or more and 10.0 μm or less. In the coated cutting tool of this embodiment, when the average thickness of the entire coating layer is 0.5 μm or more, the wear resistance of the coated cutting tool in high-speed machining is improved. Furthermore, in the coated cutting tool of this embodiment, when the average thickness of the entire coating layer is 10.0 μm or less, the chipping resistance is further improved in both high-speed machining and high-feed machining, mainly due to the suppression of peeling of the coating layer. From the same perspective, the average thickness of the entire coating layer is more preferably 0.6 μm or more and 9.6 μm or less, and even more preferably 1.2 μm or more and 7.8 μm or less.

[0021] [First alternate laminated structure] In the coated cutting tool of this embodiment, the coating layer has a first alternating laminate structure in which two or more layers A and two or more layers B are alternately formed. The coated cutting tool of this embodiment has the first alternating laminate structure in which two or more layers A and two or more layers B containing a compound having a specific composition are alternately formed, thereby improving thermal shock resistance and providing excellent fracture resistance during high-speed machining.

[0022] [A layer] In the coated cutting tool of this embodiment, the layer A is a compound layer containing a compound having a composition represented by the following formula (1). (Al a Cr b Ti 1-a-b )N (1) (In formula (1), a is the content ratio (atomic ratio) of Al element to the total of Al element, Cr element, and Ti element, 0.50≦a≦0.68 is satisfied, b is the content ratio (atomic ratio) of Cr element to the total of Al element, Cr element, and Ti element, 0.02≦b≦0.30 is satisfied, 1-ab is the content ratio (atomic ratio) of Ti element to the total of Al element, Cr element, and Ti element, 0.11≦1-ab≦0.40.)

[0023] In the layer A forming the first alternating laminate structure, the composition represented by formula (1) (Al a Cr b Ti 1-a-b When the content ratio a of Al element in )N is 0.50 or more, the hardness and oxidation resistance are increased, and the coated cutting tool has excellent wear resistance in high-speed machining. On the other hand, when the content ratio a of Al element is 0.68 or less, the formation of hexagonal crystals is suppressed, thereby increasing the hardness and making the coated cutting tool have excellent wear resistance in high-speed machining. In addition, the thermal stability in the vicinity of the interface between the A layer and the B layer is improved, resulting in improved thermal shock resistance, and further improving the chipping resistance of the coated cutting tool in high-speed machining. From the same viewpoint, (Al a Cr b Ti 1-a-b The content ratio a of Al element in N is preferably 0.51 or more and 0.67 or less, and more preferably 0.55 or more and 0.66 or less.

[0024] In addition, in the layer A forming the first alternate laminate structure, the composition represented by formula (1) (Al a Cr b Ti 1-a-b When the content ratio b of Cr element in )N is 0.02 or more, the formation of hexagonal crystals is suppressed, resulting in increased hardness and excellent wear resistance of the coated cutting tool in high-speed machining. In addition, the thermal stability in the vicinity of the interface between the A layer and the B layer is improved, resulting in improved thermal shock resistance, and further improving the chipping resistance of the coated cutting tool in high-speed machining. On the other hand, when the content ratio b of Cr element is 0.30 or less, the toughness is improved, improving the chipping resistance of the coated cutting tool in both high-speed machining and high-feed machining. From the same viewpoint, a Cr b Ti 1-a-b The content ratio b of Cr element in N is preferably 0.03 or more and 0.29 or less, and more preferably 0.04 or more and 0.25 or less.

[0025] In addition, in the layer A forming the first alternate laminate structure, the composition represented by formula (1) (Al a Cr b Ti 1-a-bWhen the Ti content (1-ab) in )N is 0.11 or more, the thermal stability of the interface between the A layer and the B layer is improved, improving thermal shock resistance. Furthermore, peeling of the coating layer and the propagation of cracks into the substrate during cutting are suppressed, resulting in the coated cutting tool having excellent chipping resistance in high-speed machining. On the other hand, when the Ti content (1-ab) is 0.40 or less, if the Al content (a) is relatively large, the hardness increases and oxidation resistance improves, resulting in the coated cutting tool having excellent wear resistance in high-speed machining. Furthermore, if the Cr content (b) is relatively large, the formation of hexagonal crystals is suppressed, resulting in the hardness increasing and the coated cutting tool having excellent wear resistance in high-speed machining. From the same perspective, (Al a Cr b Ti 1-a-b The content ratio (1-ab) of Ti element in N is preferably 0.12 or more and 0.38 or less, and more preferably 0.15 or more and 0.36 or less.

[0026] In this embodiment, the composition of each compound layer is, for example, (Al 0.60 Cr 0.20 Ti 0.20 When expressed as )N, it means that the content ratio (atomic ratio) of Al element to the total of Al element, Cr element, and Ti element is 0.60, the content ratio (atomic ratio) of Cr element to the total of Al element, Cr element, and Ti element is 0.20, and the content ratio (atomic ratio) of Ti element to the total of Al element, Cr element, and Ti element is 0.20. 、A This means that the amount of Al element relative to the total of Al element, Cr element and Ti element is 60%, the amount of Cr element relative to the total of Al element, Cr element and Ti element is 20%, and the amount of Ti element relative to the total of Al element, Cr element and Ti element is 20%.

[0027] [B layer] In the coated cutting tool of this embodiment, the layer B is a compound layer containing a compound having a composition represented by the following formula (2). (Al c Ti 1-c-d B d )N (2) (In formula (2), c is the content ratio (atomic ratio) of Al element to the total of Al element, Ti element, and B element, 0.30≦c≦0.64 is satisfied, d is the content ratio (atomic ratio) of the B element to the total of the Al element, the Ti element, and the B element, 0.01≦c≦0.10 is satisfied, 1-cd is the content ratio (atomic ratio) of Ti element to the total of Al element, Ti element, and B element, 0.30≦1-cd≦0.69 is satisfied.)

[0028] In the B layer forming the first alternate laminate structure, the composition represented by formula (2) (Al c Ti 1-c-d B d When the content ratio c of Al element in )N is 0.30 or more, the hardness and oxidation resistance are increased, and the coated cutting tool has excellent wear resistance in high-speed machining. On the other hand, when the content ratio c of Al element is 0.64 or less, the formation of hexagonal crystals is suppressed, thereby increasing the hardness and making the coated cutting tool have excellent wear resistance in high-speed machining. In addition, the thermal stability in the vicinity of the interface between the A layer and the B layer is improved, resulting in improved thermal shock resistance, and further improving the chipping resistance of the coated cutting tool in high-speed machining. From the same viewpoint, (Al c Ti 1-c-d B d The content ratio c of Al element in N is preferably 0.31 or more and 0.63 or less, and more preferably 0.33 or more and 0.56 or less.

[0029] In addition, in the B layer forming the first alternate laminate structure, the composition represented by formula (2) (Al c Ti 1-c-d B d When the content ratio d of the B element in )N is 0.01 or more, the hardness is increased, and the coated cutting tool has excellent wear resistance in high-speed machining. On the other hand, when the content ratio d of the B element is 0.10 or less, the toughness is improved, and the chipping resistance of the coated cutting tool in both high-speed machining and high-feed machining is improved. From the same viewpoint, (Al c Ti 1-c-d B dThe content ratio d of B element in N is preferably 0.02 or more and 0.09 or less, and more preferably 0.02 or more and 0.07 or less.

[0030] In addition, in the B layer forming the first alternate laminate structure, the composition represented by formula (2) (Al c Ti 1-c-d B d When the content ratio of Ti element in )N (1-cd) is 0.30 or more, the thermal stability of the interface between the A layer and the B layer is improved, the thermal shock resistance is improved, and peeling of the coating layer and the propagation of cracks into the substrate during cutting are suppressed, so that the coated cutting tool has excellent chipping resistance in high-speed machining. On the other hand, when the content ratio of Ti element (1-cd) is 0.69 or less, if the content ratio of Al element c is relatively large, the hardness is increased and the oxidation resistance is improved, and the coated cutting tool has excellent wear resistance in high-speed machining. Also, if the content ratio of B element d is relatively large, the hardness is increased and the coated cutting tool has excellent wear resistance in high-speed machining. From the same perspective, (Al c Ti 1-c-d B d The content ratio of Ti element in N (1-cd) is preferably 0.32 or more and 0.67 or less, and more preferably 0.37 or more and 0.65 or less.

[0031] In the coated cutting tool of this embodiment, when a lower layer (described later) is not formed, it is preferable to first form Layer A on the surface of the substrate, as this tends to improve adhesion between the substrate and the coating layer.

[0032] In the coated cutting tool of this embodiment, the number of repetitions of the A layer and the B layer in the first alternating laminate structure is 2 or more, preferably 5 to 500 times, and more preferably 6 to 96 times. In this embodiment, when one layer A and one layer B are formed, the "number of repetitions" is one.

[0033] In the coated cutting tool of this embodiment, the average thickness of the first alternating laminate structure is 0.50 μm or more and 10.00 μm or less. When the average thickness of the first alternating laminate structure is 0.50 μm or more, the wear resistance of the coated cutting tool in high-speed machining is improved. On the other hand, when the average thickness of the first alternating laminate structure is 10.00 μm or less, peeling of the coating layer can be suppressed, and the chipping resistance of the coated cutting tool in both high-speed machining and high-feed machining is improved. From the same perspective, the average thickness of the first alternating laminate structure is preferably 0.60 μm or more and 9.60 μm or less, and more preferably 1.20 μm or more and 7.80 μm or less. In this embodiment, the average thickness of the first alternating laminate structure described here is, for example, the sum of the average thicknesses of the multiple first alternating laminate structures when multiple first alternating laminate structures and multiple second alternating laminate structures are formed alternately, such as the third alternating laminate structure described below.

[0034] In the coated cutting tool of this embodiment, the average thickness of each of the A and B layers in the first alternating laminate structure is 2 nm or more and 300 nm or less. When the average thickness of each of the A and B layers in the first alternating laminate structure is 2 nm or more, the effect of suppressing the propagation of cracks generated during machining into the substrate is improved, and the chipping resistance of the coated cutting tool is improved in both high-speed and high-feed machining. On the other hand, when the average thickness of each of the A and B layers in the first alternating laminate structure is 300 nm or less, the effect of having an alternating laminate structure consisting of two different layers is obtained, resulting in increased hardness, excellent wear resistance in high-speed machining, and the coated cutting tool is further effective in suppressing the propagation of cracks generated during machining into the substrate, and the chipping resistance of the coated cutting tool is improved in both high-speed and high-feed machining. From the same perspective, the average thickness of each of the A and B layers in the first alternating laminate structure is preferably 3 nm or more and 280 nm or less, and more preferably 5 nm or more and 150 nm or less. In the first alternate laminated structure, the average thickness per layer of the A layer and the B layer may be the same or different.

[0035] In the first alternate laminate structure, the ratio ((1-ab) / d) of the content (atomic ratio) of Ti element in the A layer to the content (atomic ratio) of B element in the B layer is preferably 2.0 or more and 25.0 or less. In the first alternating laminate structure, when the ratio ((1-ab) / d) of the Ti element content (atomic ratio) in the A layer to the B element content (atomic ratio) in the B layer is 2.0 or more, the thermal stability near the interface between the A layer and the B layer is improved, which tends to result in improved thermal shock resistance, and the chipping resistance of the coated cutting tool during high-speed machining is also improved. Furthermore, the toughness near the interface between the A layer and the B layer is also improved, which tends to result in improved chipping resistance during high-feed machining of the coated cutting tool. On the other hand, in the first alternating laminate structure, when the ratio ((1-ab) / d) is 25.0 or less, the coating layer having the first alternating laminate structure tends to have a greater effect in improving thermal shock resistance, and the chipping resistance of the coated cutting tool during high-speed machining is also improved. From the same viewpoint, the ratio ((1-ab) / d) is more preferably 2.4 or more and 24.0 or less, and even more preferably 3.0 or more and 13.0 or less.

[0036] In the first alternate laminate structure, the average value ((a+c) / 2) of the content ratio (atomic ratio) of Al element in the A layer and the content ratio (atomic ratio) of Al element in the B layer is preferably 0.50 or more and 0.62 or less. In the first alternating laminate structure, when the average value ((a+c) / 2) of the Al element content (atomic ratio) in Layer A and the Al element content (atomic ratio) in Layer B is 0.50 or more, the hardness and oxidation resistance tend to be increased, and the wear resistance of the coated cutting tool during high-speed machining tend to be improved. On the other hand, in the first alternating laminate structure, when the average value ((a+c) / 2) is 0.62 or less, the formation of hexagonal crystals is suppressed, and the hardness tends to be increased, and the wear resistance of the coated cutting tool during high-speed machining tends to be improved. Furthermore, the thermal stability near the interface between Layer A and Layer B tends to be improved, and the thermal shock resistance tends to be further increased, and the chipping resistance of the coated cutting tool during high-speed machining tends to be further improved. From the same perspective, the average value ((a+c) / 2) is more preferably 0.51 or more and 0.61 or less, and even more preferably 0.53 or more and 0.60 or less.

[0037] [Second alternate laminated structure] In the coated cutting tool of this embodiment, the coating layer preferably further has a second alternating laminate structure in which two or more A layers and two or more C layers are alternately formed. The layer C in the second alternate laminated structure contains a compound having a composition represented by the following formula (3). (Al e Ti 1-e )N (3) (In formula (3), e is the Al element. Basic and the content ratio (atomic ratio) of Al element to the total of Ti element, 0.30≦e≦0.64 is satisfied, 1-e is Al element Basic and the content ratio (atomic ratio) of Ti element to the total amount of Ti element, 0.36≦1-e≦0.70 is satisfied.) The layer A in the second alternate laminated structure is the same as the layer A in the first alternate laminated structure. When the second alternating laminate structure is formed on the surface of the first alternating laminate structure facing the substrate, the adhesion between the coating layer and the substrate tends to be further improved. Also, when the second alternating laminate structure is formed on the surface of the first alternating laminate structure facing away from the substrate, or when the second alternating laminate structure is formed between two first alternating laminates, the effect of suppressing the propagation of cracks generated during processing to the substrate tends to be further improved. For the above reasons, in the coated cutting tool of this embodiment, when the coating layer has the second alternating laminate structure, fracture resistance tends to be further improved in both high-speed cutting and high-feed cutting.

[0038] [C layer] In the coated cutting tool of this embodiment, the C layer is a compound layer containing a compound having the composition represented by the above formula (3). In the C layer forming the second alternate laminated structure, the composition represented by formula (3) (Al e Ti 1-e When the content ratio e of Al element in )N is 0.30 or more, the hardness and oxidation resistance tend to be increased, and the wear resistance of the coated cutting tool in high-speed machining tends to be improved. On the other hand, in the C layer forming the second alternating laminated structure, the composition represented by formula (3) (Al e Ti 1-e When the content ratio e of Al element in )N is 0.64 or less, the formation of hexagonal crystals is suppressed, so that the hardness tends to be high and the wear resistance of the coated cutting tool in high-speed machining tends to be improved. From the same point of view, the composition represented by formula (3) (Al e Ti 1-e The content ratio e of Al element in N is preferably 0.35 or more and 0.60 or less, and more preferably 0.40 or more and 0.55 or less. In addition, in the C layer forming the second alternate laminated structure, the composition represented by formula (3) (Al e Ti 1-e When the content ratio (1-e) of Ti element in )N is 0.36 or more, the formation of hexagonal crystals is suppressed, so that the hardness tends to be high and the wear resistance of the coated cutting tool in high-speed machining tends to be improved. On the other hand, in the C layer forming the second alternating laminated structure, the composition represented by formula (3) (Ale Ti 1-e When the content ratio (1-e) of Ti element in )N is 0.70 or less, the hardness and oxidation resistance tend to be increased, and the wear resistance of the coated cutting tool in high-speed machining tends to be improved. From the same viewpoint, the composition represented by formula (3) (Al e Ti 1-e The content ratio (1-e) of Ti element in N is preferably 0.40 or more and 0.65 or less, and more preferably 0.45 or more and 0.60 or less.

[0039] In the coated cutting tool of this embodiment, the number of repetitions of the A layer and the C layer in the second alternating laminate structure is 2 or more, preferably 5 to 250 times, and more preferably 6 to 75 times. In this embodiment, when one layer A and one layer C are formed, the "number of repetitions" is one.

[0040] In the coated cutting tool of this embodiment, the average thickness of the second alternating laminate structure is preferably 0.50 μm or more and 5.00 μm or less. When the average thickness of the second alternating laminate structure is 0.50 μm or more, the wear resistance of the coated cutting tool during high-speed machining tends to be improved. On the other hand, when the average thickness of the second alternating laminate structure is 5.00 μm or less, peeling of the coating layer can be suppressed, and the chipping resistance of the coated cutting tool during both high-speed machining and high-feed machining tends to be further improved. From the same perspective, the average thickness of the second alternating laminate structure is preferably 0.60 μm or more and 4.50 μm or less, and more preferably 1.00 μm or more and 3.00 μm or less. In this embodiment, the average thickness of the second alternating laminate structure described herein is, for example, the sum of the average thicknesses of the multiple second alternating laminate structures when multiple first alternating laminate structures and multiple second alternating laminate structures are formed alternately, such as the third alternating laminate structure described below.

[0041] In the coated cutting tool of this embodiment, the average thickness of each of the A layer and the C layer in the second alternating laminate structure is preferably 2 nm or more and less than 30 nm. When the average thickness of each of the A layer and the C layer in the second alternating laminate structure is 2 nm or more, the effect of suppressing the propagation of cracks generated during machining into the substrate is improved, and the fracture resistance of the coated cutting tool tends to be improved in both high-speed and high-feed machining. On the other hand, when the average thickness of each of the A layer and the C layer in the second alternating laminate structure is less than 30 nm, the decrease in adhesion due to the difference in residual stress between the first and second alternating laminate structures is suppressed, and peeling is suppressed, which tends to further improve the fracture resistance of the coated cutting tool in both high-speed and high-feed machining. From the same perspective, the average thickness of each of the A layer and the C layer in the second alternating laminate structure is preferably 3 nm or more and 27 nm or less, and more preferably 4 nm or more and 25 nm or less. In the second alternate laminated structure, the average thickness per layer of the A layer and the C layer may be the same or different. The average thickness of each layer forming the first alternating laminate structure is preferably greater than the average thickness of each layer forming the second alternating laminate structure. A first alternating laminate structure containing element B is prone to high residual stress. Therefore, by making the average thickness of each layer forming the first alternating laminate structure greater than the average thickness of each layer forming the second alternating laminate structure, and more preferably by setting the average thickness of each layer within the above-mentioned range, the difference in residual stress between the first and second alternating laminate structures tends to be reduced. Specifically, in this case, for example, the average thickness of each layer A and B in the first alternating laminate structure is preferably 30 nm or more and 300 nm or less. When the average thickness of each layer A and B in the first alternating laminate structure is 30 nm or more, the decrease in adhesion due to the difference in residual stress between the first and second alternating laminates is suppressed, and peeling is also suppressed, which tends to further improve the chipping resistance of the coated cutting tool in both high-speed and high-feed machining. Furthermore, when the average thickness per layer of the A layer and the B layer in the first alternating laminate structure is 300 nm or less, the effect of having the first alternating laminate is exerted, and toughness is improved, so that the coated cutting tool tends to have excellent chipping resistance.

[0042] [Third alternate laminated structure] In the coated cutting tool of this embodiment, the coating layer preferably has a third alternating laminate structure in which the first alternating laminate structure and the second alternating laminate structure are alternately formed three or more times in total. The presence of the third alternating laminate structure in the coated cutting tool of this embodiment tends to further improve the effect of suppressing the propagation of cracks generated during machining into the base material, and also tends to further improve fracture resistance in both high-speed machining and high-feed machining.

[0043] In the coated cutting tool of this embodiment, when the third alternating laminate structure is included, the average thickness per structure of the first alternating laminate structure in the third alternating laminate structure is preferably 0.1 μm or more and 1.5 μm or less. In the coated cutting tool of this embodiment, when the third alternating laminate structure is included, if the average thickness per structure of the first alternating laminate structure is 0.1 μm or more, a decrease in adhesion due to a difference in residual stress between the first alternating laminate structure and the second alternating laminate structure is suppressed, and fracture resistance tends to be further improved in both high-speed and high-feed machining. On the other hand, in the coated cutting tool of this embodiment, when the third alternating laminate structure is included, if the average thickness per structure of the first alternating laminate structure is 1.5 μm or less, the effect of the third alternating laminate structure is obtained, and the effect of suppressing the propagation of cracks generated during machining into the base material tends to be further improved, and fracture resistance tends to be further improved in both high-speed and high-feed machining. From the same viewpoint, when the third alternating laminate structure is present, the average thickness per structure of the first alternating laminate structure is more preferably 0.2 μm or more and 1.2 μm or less, and even more preferably 0.2 μm or more and 1.0 μm or less. In this embodiment, the average thickness per structure of the first alternating laminate structure in the third alternating laminate structure is the sum of the average thicknesses of each first alternating laminate structure formed in the third alternating laminate structure divided by the number of first alternating laminate structures formed.For example, if the coating layer is configured as "substrate / first alternating laminate structure / second alternating laminate structure / first alternating laminate structure / second alternating laminate structure / first alternating laminate structure / second alternating laminate structure (outermost surface)", the average thickness per structure of the first alternating laminate structure is the sum of the average thicknesses of each of the three first alternating laminate structures formed in the third alternating laminate structure divided by the number of first alternating laminate structures formed, "3". Furthermore, in the coated cutting tool of this embodiment, when the coated cutting tool has a third alternating laminate structure, the average thickness per structure of the second alternating laminate structure in the third alternating laminate structure is preferably 0.1 μm or more and 1.5 μm or less. In the coated cutting tool of this embodiment, when the coated cutting tool has a third alternating laminate structure, if the average thickness per structure of the second alternating laminate structure is 0.1 μm or more, a decrease in adhesion due to a difference in residual stress between the first and second alternating laminate structures is suppressed, and fracture resistance tends to be further improved in both high-speed and high-feed machining. On the other hand, in the coated cutting tool of this embodiment, when the coated cutting tool has a third alternating laminate structure, if the average thickness per structure of the second alternating laminate structure is 1.5 μm or less, the effect of the third alternating laminate structure is obtained, and the effect of suppressing the propagation of cracks generated during machining into the base material tends to be further improved, and fracture resistance tends to be further improved in both high-speed and high-feed machining. From the same viewpoint, when the third alternating laminate structure is present, the average thickness per structure of the second alternating laminate structure is more preferably 0.2 μm or more and 0.6 μm or less, and even more preferably 0.3 μm or more and 0.6 μm or less. In this embodiment, the average thickness per structure of the second alternating laminate structure in the third alternating laminate structure is the sum of the average thicknesses of each second alternating laminate structure formed in the third alternating laminate structure divided by the number of second alternating laminate structures formed.For example, if the coating layer is configured as "substrate / first alternating laminate structure / second alternating laminate structure / first alternating laminate structure / second alternating laminate structure / first alternating laminate structure / second alternating laminate structure (outermost surface)", the average thickness per structure of the second alternating laminate structure is the sum of the average thicknesses of each of the three second alternating laminate structures formed in the third alternating laminate structure divided by the number of second alternating laminate structures formed, "3".

[0044] In the coated cutting tool of this embodiment, in the third alternating laminate structure, the number of repetitions of the first alternating laminate structure and the second alternating laminate structure is preferably 1.5 to 45, and more preferably 2.5 to 9. In this embodiment, if one first alternating stack structure and one second alternating stack structure are formed, the "number of repetitions" is one, and if a total of three alternating stack structures are formed, for example, first alternating stack structure / second alternating stack structure / first alternating stack structure, the "number of repetitions" is 1.5.

[0045] In the coated cutting tool of this embodiment, when the coating layer has a first alternating laminate structure, in X-ray diffraction of the first alternating laminate structure, it is preferable that the ratio (I(111) / I(200)) of the diffraction peak intensity (I(111)) of the cubic (111) plane to the diffraction peak intensity (I(200)) of the cubic (200) plane is 0.5 or more and 5.0 or less. Furthermore, in the coated cutting tool of this embodiment, when the coating layer has a third alternating laminate structure, in X-ray diffraction of the third alternating laminate structure, it is preferable that the ratio (I(111) / I(200)) of the diffraction peak intensity (I(111)) of the cubic (111) plane to the diffraction peak intensity (I(200)) of the cubic (200) plane is 0.5 or more and 5.0 or less. In the coated cutting tool of this embodiment, when the ratio (I(111) / I(200)) of the diffraction peak intensity (I(111)) of the cubic (111) plane to the diffraction peak intensity (I(200)) of the cubic (200) plane in X-ray diffraction of the first alternating laminate structure or the third alternating laminate structure is 0.5 or more, the hardness of the coating layer increases, and the wear resistance tends to be excellent. On the other hand, in the coated cutting tool of this embodiment, when the diffraction peak intensity ratio (I(111) / I(200)) is 5.0 or less, the toughness of the coating layer improves, and the chipping resistance tends to be excellent. From the same viewpoint, the diffraction peak intensity ratio (I(111) / I(200)) is more preferably 1.1 or more and 4.8 or less, and even more preferably 1.8 or more and 4.5 or less. In this embodiment, the measurement positions for calculating the diffraction peak intensity ratio are three arbitrary points included in the area involved in cutting (it is preferable to select these points at a distance of 0.5 mm or more from each other so that they can represent the stress in the area).

[0046] The peak intensity of each plane index in the coating layer of this embodiment can be determined using a commercially available X-ray diffractometer. For example, the peak intensity of each plane index can be measured by measuring X-ray diffraction using a 2θ / θ focusing optical system with Cu-Kα radiation using a SmartLab X-ray diffractometer manufactured by Rigaku Corporation under the following conditions. The measurement conditions are: output: 45 kV, 200 mA, incident-side Soller slit: 5°, divergence vertical slit: 2 / 3°, divergence vertical limiting slit: 5 mm, scattering slit: 8 mm, receiving-side Soller slit: 5°, receiving slit: 0.3 mm, sampling width: 0.02°, scan speed: 1° / min, and 2θ measurement range: 30° to 90°. The peak intensity of each plane index can be determined from the X-ray diffraction pattern using analysis software provided with the X-ray diffractometer. In the analysis software, background processing and Kα2 peak removal are performed using a cubic approximation, and profile fitting is performed using a Pearson-VII function to determine the intensity of each peak. Specifically, the intensity can be measured and calculated by the method described in the Examples below.

[0047] Fig. 1 is a schematic cross-sectional view showing an example of a coated cutting tool according to this embodiment. The coated cutting tool 1 includes a substrate 2 and a coating layer 3 formed on the surface of the substrate 2. The coating layer 3 has a first alternating laminate structure 4 in which, from the substrate 2 side, A layers 41 and B layers 42 are alternately and repeatedly formed. In the first alternating laminate structure shown in Fig. 1, the A layers 41 and the B layers 42 are each alternately repeated six times. FIG. 2 is a schematic cross-sectional view showing yet another example of a coated cutting tool according to this embodiment. The coated cutting tool 1 includes a substrate 2 and a coating layer 3 formed on the surface of the substrate 2. The coating layer 3 has a third alternating laminate structure 6 in which, starting from the substrate 2, a first alternating laminate structure 4 and a second alternating laminate structure 5 are alternately and repeatedly formed. The first alternating laminate structure 4 is formed by, starting from the substrate 2, alternatingly repeating an A layer 41 and a B layer 42. The second alternating laminate structure 5 is formed by, starting from the substrate 2, alternatingly repeating an A layer 51 and a C layer 52. In the third alternating laminate structure shown in FIG. 2, the first alternating laminate structure 4 and the second alternating laminate structure 5 are each alternately repeated twice.

[0048] Bottom Layer The coating layer used in this embodiment may be composed of only the first or third alternating laminate structure described above, but preferably has a lower layer between the substrate and the first or third alternating laminate structure. By having a lower layer, the adhesion between the substrate and the coating layer tends to be further improved. From the same viewpoint, the lower layer is preferably a single layer or multiple layers of a compound consisting of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, B, and Y, and at least one element selected from the group consisting of C, N, O, and B (however, the composition of the compound constituting the lower layer is different from the composition of the compound constituting the layer of the first or second alternating laminate structure that is in contact with the lower layer), and preferably contains at least one element selected from the group consisting of Ti, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y. It is more preferred that the lower layer is a single layer or a multilayer of a compound consisting of at least one element selected from the group consisting of Ti, Ta, Cr, Mo, W, Al, Si, and Y, and at least one element selected from the group consisting of N and B, and it is particularly preferred that the lower layer is a single layer or a multilayer of a compound consisting of at least one element selected from the group consisting of Ti, Cr, Mo, and Al, and N. Specific compounds contained in the lower layer are not particularly limited, but examples include TiMoN, CrN, TiAlCrN, TiAlN, TiN, TiCN, and AlCrN.

[0049] In the coated cutting tool of this embodiment, the average thickness of the lower layer is preferably 0.01 μm or more and 2.00 μm or less. In the coated cutting tool of this embodiment, if the average thickness of the lower layer is 0.01 μm or more, adhesion between the coating layer and the substrate tends to be further improved, and fracture resistance tends to be further improved in both high-speed machining and high-feed machining. On the other hand, in the coated cutting tool of this embodiment, if the average thickness of the lower layer is 2.00 μm or less, peeling of the coating layer is suppressed, and fracture resistance tends to be further improved in both high-speed machining and high-feed machining. From the same viewpoint, the average thickness of the lower layer is more preferably 0.02 μm or more and 1.00 μm or less, and even more preferably 0.10 μm or more and 0.50 μm or less.

[0050] [Top layer] The coating layer used in this embodiment may be composed solely of the first or third alternating laminate structure described above, or may have an upper layer on the surface of the first or third alternating laminate structure opposite the substrate. The upper layer is preferably a single layer or multiple layers of a compound having a composition represented by formulas (1) to (3), which comprises at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y, and at least one element selected from the group consisting of C, N, O, and B (however, the composition of the compound constituting the upper layer is different from the composition of the compound constituting the layer of the first or second alternating laminate structure that is in contact with the upper layer). When the upper layer is a single layer or multiple layers of such compounds, wear resistance tends to be even better. From the same viewpoint, the upper layer preferably contains a compound consisting of at least one element selected from the group consisting of Ti, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y and at least one element selected from the group consisting of C, N, O, and B. It is even more preferable that the upper layer contains a compound consisting of at least one element selected from the group consisting of Ti, Nb, Ta, Cr, Mo, W, Al, Si, and Y and at least one element selected from the group consisting of N and B. It is particularly preferable that the upper layer contains a compound consisting of at least one element selected from the group consisting of Ti, Nb, Mo, Al, and Si and at least one element selected from the group consisting of N and B. Specific compounds contained in the upper layer are not particularly limited, but examples include TiN, TiAlN, TiSiN, TiMoN, NbN, and TiAlBN. The upper layer may be a single layer or a multilayer consisting of two or more layers.

[0051] In the coated cutting tool of this embodiment, the average thickness of the upper layer is preferably 0.01 μm or more and 2.00 μm or less. In the coated cutting tool of this embodiment, when the average thickness of the upper layer is 0.01 μm or more, the wear resistance tends to be excellent in high-speed machining. On the other hand, in the coated cutting tool of this embodiment, when the average thickness of the upper layer is 2.00 μm or less, peeling of the coating layer is suppressed, and the chipping resistance tends to be further improved in both high-speed machining and high-feed machining. From the same viewpoint, the average thickness of the upper layer is more preferably 0.20 μm or more and 1.50 μm or less, and even more preferably 0.50 μm or more and 1.50 μm or less.

[0052] [Method of manufacturing the coating layer] The method for producing the coating layer of the coated cutting tool of this embodiment is not particularly limited, but examples include physical vapor deposition methods such as ion plating, arc ion plating, sputtering, and ion mixing. Forming the coating layer using physical vapor deposition is preferable because it can form a sharp edge. Among these, arc ion plating is more preferable because it provides better adhesion between the coating layer and the substrate.

[0053] [Method of manufacturing coated cutting tools] The method for manufacturing the coated cutting tool of this embodiment will be described below using a specific example. Note that the method for manufacturing the coated cutting tool of this embodiment is not particularly limited as long as it can achieve the configuration of the coated cutting tool.

[0054] First, the substrate processed into the tool shape is placed in the reaction vessel of the physical vapor deposition device, and the metal evaporation source is installed in the reaction vessel. Then, the pressure in the reaction vessel is increased to 1.0 × 10 -2The reactor is evacuated to a vacuum of 100 Pa or less, and the substrate is heated to a temperature of 200°C to 700°C using a heater inside the reactor. After heating, Ar gas is introduced into the reactor, and the pressure inside the reactor is set to 0.5 Pa to 5.0 Pa. In an Ar gas atmosphere with a pressure of 0.5 Pa to 5.0 Pa, a bias voltage of -500 V to -350 V is applied to the substrate, and a current of 40 A to 50 A is passed through the tungsten filament inside the reactor, and ion bombardment treatment with Ar gas is performed on the surface of the substrate. After ion bombardment treatment has been performed on the surface of the substrate, the pressure inside the reactor is increased to 1.0 x 10 -2 The vacuum is drawn until the pressure reaches a vacuum of 100 Pa or less.

[0055] When forming the lower layer used in this embodiment, the substrate is controlled until its temperature reaches 300°C to 500°C. After this control, gas is introduced into the reaction vessel to adjust the pressure inside the reaction vessel to 3.0 Pa to 5.0 Pa. Examples of the gas include N2 gas when the lower layer is composed of a compound consisting of N and at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y. Examples of the gas include a mixed gas of N2 gas and C2H2 gas when the lower layer is composed of a compound consisting of N and C and at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y. The volume ratio of the mixed gas is not particularly limited, but may be, for example, N2 gas:C2H2 gas = 95:5 to 85:15. Next, a bias voltage of −120V to −30V is applied to the substrate, and a metal evaporation source according to the metal component of each layer is evaporated by arc discharge with an arc current of 80A to 150A to form the lower layer.

[0056] When forming the A layer of the first and second alternating laminate structures used in this embodiment, the temperature of the substrate is controlled to 300°C to 500°C, N2 gas is introduced into the reaction vessel, and the pressure inside the reaction vessel is set to 3.0 Pa to 5.0 Pa. Thereafter, a bias voltage of -80 V to -40 V is applied to the substrate, and a metal evaporation source according to the metal component of the A layer is evaporated by arc discharge at 80 A to 150 A, to form the A layer.

[0057] When forming the B layer of the first alternating laminate structure and the C layer of the second alternating laminate structure used in this embodiment, the temperature of the substrate is controlled to 300°C to 500°C. It is preferable to maintain the temperature of the substrate at the same temperature as that used when forming the A layer, since this allows the A and B layers, or the A and C layers, to be formed continuously. After controlling the temperature, N2 gas is introduced into the reaction vessel, and the pressure inside the reaction vessel is set to 3.0 Pa to 5.0 Pa. Next, a bias voltage of -80 V to -40 V is applied to the substrate, and a metal evaporation source corresponding to the metal component of the B or C layer is evaporated by arc discharge with an arc current of 80 A to 150 A, thereby forming the B or C layer.

[0058] To form a first alternating laminated structure in which two or more A layers and two or more B layers are alternately laminated, each layer may be formed alternately by alternately evaporating a metal evaporation source corresponding to the metal component of layer A and a metal evaporation source corresponding to the metal component of layer B by arc discharge under the conditions described above. The thickness of each layer constituting the alternating laminated structure can be controlled by adjusting the arc discharge time of the metal evaporation source corresponding to the metal component of layer A and the metal evaporation source corresponding to the metal component of layer B. The same applies to the case where a second alternate laminated structure is formed in which two or more layers of A and two or more layers of C are alternately laminated.

[0059] In order to set the composition of the entire compound and the atomic ratios ((1-ab) / d) and ((a+c) / 2) in the alternating laminate structure used in this embodiment to predetermined values, it is advisable to adjust the thickness of each layer in the alternating laminate structure and the ratio of metal elements in each layer in the process of forming the alternating laminate structure.

[0060] In order to set the X-ray diffraction peak intensity ratio (I(111) / I(200)) of the coating layer used in this embodiment to a predetermined value, it is advisable to adjust the temperature of the substrate, the bias voltage, or the pressure in the reaction vessel during the process of forming the layer-by-layer structure. More specifically, during the process of forming the layer-by-layer structure, if the temperature of the substrate is lowered, the negative bias voltage is increased (in the direction away from zero), or the pressure in the reaction vessel is lowered, the X-ray diffraction peak intensity ratio (I(111) / I(200)) tends to increase.

[0061] The upper layer used in this embodiment may be formed under the same manufacturing conditions as the lower layer described above. Specifically, first, the substrate is heated to a temperature of 300°C to 500°C. After this, gas is introduced into the reaction vessel to adjust the pressure within the reaction vessel to 3.0 Pa to 5.0 Pa. Examples of suitable gases include N2 gas when the upper layer is composed of a compound containing N and at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y. Alternatively, examples of suitable gases include a mixture of N2 gas and C2H2 gas when the upper layer is composed of a compound containing N and C and at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y. The volume ratio of the mixed gas is not particularly limited, but may be, for example, N2 gas:C2H2 gas = 95:5 to 85:15. Next, a bias voltage of −120V to −30V is applied to the substrate, and a metal evaporation source according to the metal component of each layer is evaporated by arc discharge with an arc current of 80A to 150A, to form the upper layer.

[0062] The thickness of each layer constituting the coating layer of the coated cutting tool of this embodiment can be measured from the cross-sectional structure of the coated cutting tool using an optical microscope, a scanning electron microscope (SEM), a transmission electron microscope (TEM), etc. The average thickness of each layer of the coated cutting tool of this embodiment can be determined by measuring the thickness of each layer from three or more cross sections in the vicinity of a position 50 μm from the cutting edge ridge of the surface facing the metal evaporation source toward the center of the surface, and calculating the average value (arithmetic mean value) of the measurements.

[0063] Furthermore, the composition of each layer constituting the coating layer in the coated cutting tool of this embodiment can be measured from the cross-sectional structure of the coated cutting tool of this embodiment using an energy dispersive X-ray analyzer (EDS) or a wavelength dispersive X-ray analyzer (WDS), for example.

[0064] The coated cutting tool of this embodiment is considered to have the effect of extending the tool life compared to conventional tools in both high-speed machining and high-feed machining (however, the factors that enable the tool life to be extended are not limited to those mentioned above).Specific examples of the coated cutting tool of this embodiment include indexable cutting inserts for milling or turning, drills, and end mills. [Example]

[0065] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0066] Example 1 The substrate was a cemented carbide alloy with a composition of 86.0% WC-12.0% Co-1.0% NbC-1.0% Cr3C2 (all mass%) processed into the shape of an SNMU1307ANEN-MJ insert (manufactured by Tungaloy Corporation). A metal evaporation source was placed in the reaction chamber of the arc ion plating device so as to obtain the compound layer composition shown in Tables 1 and 2. The prepared substrate was fixed to the fixture of the rotary table inside the reaction chamber.

[0067] Then, the pressure in the reaction vessel was increased to 5.0 × 10 -3 The reactor was evacuated to a vacuum of 100 Pa or less. After evacuating, the substrate was heated to a temperature of 450° C. using a heater inside the reactor. After heating, Ar gas was introduced into the reactor so that the pressure became 2.7 Pa.

[0068] In an Ar gas atmosphere at a pressure of 2.7 Pa, a bias voltage of -400 V was applied to the substrate, and a current of 40 A was passed through the tungsten filament in the reaction vessel, and ion bombardment treatment with Ar gas was performed on the surface of the substrate for 30 minutes. After the ion bombardment treatment was completed, the pressure in the reaction vessel was increased to 5.0 × 10 -3 The vacuum was drawn until the vacuum reached 0.1 Pa or less.

[0069] For Invention Products 1 to 37 and Comparative Products 1 to 22, after evacuation, the substrate temperature was controlled to the temperature shown in Tables 3 and 4 (the temperature at the start of film formation), nitrogen gas (N2) was introduced into the reaction vessel, and the pressure inside the reaction vessel was adjusted to the pressure shown in Tables 3 and 4. Then, the bias voltage shown in Tables 3 and 4 was applied to the substrate, and metal evaporation sources for Layer A and Layer B, each with the composition shown in Tables 1 and 2, were evaporated alternately in this order by arc discharge with the arc current shown in Tables 3 and 4, thereby forming Layer A and Layer B alternately on the surface of the substrate in this order. The pressure inside the reaction vessel was controlled to the pressure shown in Tables 3 and 4. The thicknesses of Layer A and Layer B were controlled by adjusting the respective arc discharge times so as to achieve the thicknesses shown in Tables 1 and 2.

[0070] After a compound layer was formed on the surface of the substrate to the specified average thickness shown in Tables 1 and 2, the heater was turned off, and after the sample temperature had dropped to 100°C or below, the sample was removed from the reaction vessel.

[0071] The average thickness of each compound layer on the obtained sample was determined by TEM observation of three cross sections, located 50 μm from the cutting edge ridge toward the center of the surface of the coated cutting tool facing the metal evaporation source, measuring the thickness of the compound layer, and calculating the average (arithmetic mean). The average thickness per layer of A was calculated by dividing the total thickness of each A layer by the number of A layers (number of repetitions). The average thickness per layer of B was also calculated by dividing the total thickness of each B layer by the number of B layers (number of repetitions). The results are shown in Tables 1 and 2.

[0072] The composition of each compound layer of the obtained sample was measured using an EDS attached to a TEM on a cross section of the surface of the coated cutting tool facing the metal evaporation source, located 50 μm from the cutting edge toward the center. The results are also shown in Tables 1 and 2.

[0073] [Table 1]

[0074] [Table 2]

[0075] [Table 3]

[0076] [Table 4]

[0077] The ratio (I(111) / I(200)) of the diffraction peak intensity of the cubic (111) plane (I(111)) to the diffraction peak intensity of the cubic (200) plane (I(200)) in the alternating stack structure of the obtained sample was measured using an X-ray diffraction device, model: SmartLab, manufactured by Rigaku Corporation. Specifically, X-ray diffraction measurements were performed using Cu-Kα radiation in a 2θ / θ focusing optical system under the following conditions: output: 45 kV, 200 mA, incident Soller slit: 5°, divergence vertical slit: 2 / 3°, divergence vertical limiting slit: 5 mm, scattering slit: 8 mm, receiving Soller slit: 5°, receiving slit: 0.3 mm, sampling width: 0.02°, scan speed: 1° / min, 2θ measurement range: 30 to 90°. The peak intensity of the cubic (200) plane (I(200)) of the alternating layer structure and the peak intensity of the cubic (111) plane (I(111)) of the alternating layer structure were measured, and the ratio (I(111) / I(200)) was calculated. The results are shown in Tables 5 and 6. The peak intensities of the above plane indices were determined from the X-ray diffraction pattern using the analysis software provided with the X-ray diffractometer. The analysis software used a cubic approximation to remove background and the Kα2 peak, and then performed profile fitting using the Pearson-VII function to determine the intensity of each peak. The crystal system of the layer-by-layer structure was also confirmed by X-ray diffraction measurement. More specifically, the peak intensities of the cubic (200) and cubic (111) planes of the layer-by-layer structure were measured. Instead of separating the peaks from layers A and B, the peak intensity including both reflections was determined. For convenience, the ratio (I(111) / I(200)) was calculated from the peak intensities determined in this way.

[0078] [Table 5]

[0079] [Table 6]

[0080] The obtained samples were subjected to the following cutting test and evaluated.

[0081] [Cutting test] (Cutting test condition 1) High speed machining Work material: SUS304, Cutting material shape: 200mm x 150mm x 70mm plate, Cutting speed: 250m / min, Feed per tooth: 0.1mm / tooth Cutting depth: 2.0 mm, Cutting width: 70mm, Coolant: Not used, Evaluation item: The machining time until the tool flank wear width reached 0.3 mm or the cutting edge was chipped was defined as the tool life. The longer the machining time until the tool life ended, the better the chipping resistance and wear resistance. The evaluation results are shown in Tables 7 and 8. In Tables 7 and 8, for tool life under cutting test condition 1, a rating of "A" was given for tool life of 30 minutes or more, a rating of "B" for tool life of 20 minutes or more but less than 30 minutes, and a rating of "C" for tool life of less than 20 minutes. In addition, in Tables 7 and 8, for "damage," if the flank wear width reached 0.3 mm and the tool life ended, it was shown as "normal wear," and if the cutting edge was chipped and the tool life ended, it was shown as "chip."

[0082] (Cutting test condition 2) High feed rate machining Work material: SCM440, Cutting material shape: 200mm x 150mm x 25mm plate, Cutting speed: 150m / min, Feed per tooth: 0.3mm / tooth Cutting depth: 2.0 mm, Cutting width: 25mm, Coolant:Use, Evaluation item: The machining time until the cutting edge breaks off is defined as the tool life. The longer the machining time until the tool life ends, the better the breakage resistance and wear resistance. The evaluation results are shown in Tables 7 and 8. In Tables 7 and 8, for tool life under cutting test condition 2, a rating of "A" was given for tool life of 25 minutes or more, a rating of "B" for tool life of 20 minutes or more but less than 25 minutes, and a rating of "C" for tool life of less than 20 minutes.

[0083] [Table 7]

[0084] [Table 8]

[0085] From the results shown in Tables 7 and 8, the inventive products were rated "B" or higher under both cutting test condition 1 and cutting test condition 2, and did not receive a rating of "C." This indicates that the inventive products have superior chipping resistance and wear resistance to the comparative products, and have a long tool life.

[0086] Example 2 The substrate was a cemented carbide alloy with a composition of 86.0% WC-12.0% Co-1.0% NbC-1.0% Cr3C2 (by mass%) processed into an SNMU1307ANEN-MJ insert shape (manufactured by Tungaloy Corporation). A specified metal evaporation source was placed in the reaction chamber of the arc ion plating device. The prepared substrate was fixed to the fixture of the rotary table inside the reaction chamber.

[0087] Then, the pressure in the reaction vessel was increased to 5.0 × 10 -3 The reactor was evacuated to a vacuum of 100 Pa or less. After evacuating, the substrate was heated to a temperature of 450° C. using a heater inside the reactor. After heating, Ar gas was introduced into the reactor so that the pressure became 2.7 Pa.

[0088] In an Ar gas atmosphere at a pressure of 2.7 Pa, a bias voltage of -400 V was applied to the substrate, and a current of 40 A was passed through the tungsten filament in the reaction vessel, and ion bombardment treatment with Ar gas was performed on the surface of the substrate for 30 minutes. After the ion bombardment treatment was completed, the pressure in the reaction vessel was increased to 5.0 × 10 -3 The vacuum was drawn until the vacuum reached 0.1 Pa or less.

[0089] After evacuation, first alternating laminate structures and second alternating laminate structures were alternately formed on the surface of the substrate, as shown in Tables 9 and 10. The manufacturing conditions for the first alternating laminate structures were the same as those for the invention products shown in the "Composition" column of Tables 9 and 10. However, the average thickness per layer, the number of repetitions per structure, and the average thickness, as well as the total average thickness, were as shown in Tables 9 and 10. The second alternating laminate structures (types A to G) were manufactured as follows, using the compositions shown in Table 11 and the manufacturing conditions shown in Table 12. After evacuation, the substrate was controlled so that its temperature was maintained at the temperature shown in Table 12 (the temperature at the start of film formation), and nitrogen gas (N2) was introduced into the reaction vessel, and the pressure inside the reaction vessel was adjusted to the pressure shown in Table 12. Thereafter, a bias voltage shown in Table 12 was applied to the substrate, and metal evaporation sources for layers A and C having the compositions shown in Table 11 were evaporated alternately in this order by arc discharge with an arc current shown in Table 12, thereby forming layers A and C alternately on the specified surface in this order. The pressure inside the reaction vessel was controlled to be as shown in Table 12. The thicknesses of layers A and C were controlled by adjusting the arc discharge times for each layer so as to achieve the thicknesses shown in Tables 9 and 10. In general, the layers were formed in the following order from the substrate side: first alternating laminate structure / second alternating laminate structure / first alternating laminate structure / second alternating laminate structure, but in the case of invention products 44, 54, and 55, which have an * after the number in the "Number of repetitions" column in Table 10, the layers were formed in the following order from the substrate side: second alternating laminate structure / first alternating laminate structure / second alternating laminate structure / first alternating laminate structure. In addition, invention products 43 to 65 shown in Table 10 had a third alternating laminate structure in which the first alternating laminate structure and the second alternating laminate structure were alternately formed three or more times in total (number of repetitions 1.5 or more).

[0090] After forming the predetermined coating layers shown in Tables 9 and 10 on the surface of the substrate, the heater was turned off, and after the sample temperature had dropped to 100°C or below, the sample was removed from the reaction vessel.

[0091] The average thickness and composition of each layer of the obtained sample were measured and calculated in the same manner as in Example 1. The results are shown in Tables 1 and 11. Furthermore, the ratio (I(111) / I(200)) of the diffraction peak intensity (I(111)) of the cubic (111) plane to the diffraction peak intensity (I(200)) of the cubic (200) plane in the alternating stack structure of the obtained sample was also measured and calculated in the same manner as in Example 1. The results are shown in Table 13. In this example, the peaks of the first alternating stack structure and the second alternating stack structure overlapped, so the peaks were not separated and were calculated as the peak intensity including both reflections.

[0092] [Table 9]

[0093] [Table 10]

[0094] [Table 11]

[0095] [Table 12]

[0096] [Table 13]

[0097] Using the obtained samples, cutting tests were carried out in the same manner as in Example 1 to evaluate the invention products. The results are shown in Table 14.

[0098] [Table 14]

[0099] The results shown in Table 14 show that the invention product including the second alternating laminate structure has even better chipping resistance and wear resistance, and has a longer tool life.

[0100] Example 3 The substrate was a cemented carbide alloy with a composition of 86.0% WC-12.0% Co-1.0% NbC-1.0% Cr3C2 (by mass%) processed into an SNMU1307ANEN-MJ insert shape (manufactured by Tungaloy Corporation). A specified metal evaporation source was placed in the reaction chamber of the arc ion plating device. The prepared substrate was fixed to the fixture of the rotary table inside the reaction chamber.

[0101] Then, the pressure in the reaction vessel was increased to 5.0 × 10 -3 The reactor was evacuated to a vacuum of 100 Pa or less. After evacuating, the substrate was heated to a temperature of 450° C. using a heater inside the reactor. After heating, Ar gas was introduced into the reactor so that the pressure became 2.7 Pa.

[0102] In an Ar gas atmosphere at a pressure of 2.7 Pa, a bias voltage of -400 V was applied to the substrate, and a current of 40 A was passed through the tungsten filament in the reaction vessel, and ion bombardment treatment with Ar gas was performed on the surface of the substrate for 30 minutes. After the ion bombardment treatment was completed, the pressure in the reaction vessel was increased to 5.0 × 10 -3 The vacuum was drawn until the vacuum reached 0.1 Pa or less.

[0103] For Invention Products 66 to 72, after evacuation, the substrate was controlled until its temperature reached the temperature shown in Table 16 (the temperature at the start of film formation), and N2 gas was introduced into the reaction vessel, and the pressure inside the reaction vessel was adjusted to the pressure shown in Table 16. Then, a bias voltage shown in Table 16 was applied to the substrate, and a metal evaporation source having the composition of the lower layer shown in Table 15 was evaporated by arc discharge with an arc current shown in Table 16, and a lower layer having the average thickness shown in Table 15 was formed on the surface of the substrate.

[0104] Next, for Invention Products 66-72 and 76, an alternating laminate structure was formed on the surface of the lower layer as shown in Table 15. Specifically, for Invention Product 66, a first alternating laminate structure having the average thickness shown in Table 15 was formed on the surface of the lower layer under the same conditions as for Invention Product 1, for Invention Product 67, for Invention Product 18, for Invention Product 68, for Invention Product 19, for Invention Product 69, for Invention Product 6, and for Invention Product 70, for Invention Product 3. Furthermore, for Invention Products 71-72, a third alternating laminate structure having the average thickness shown in Table 15 was formed on the surface of the lower layer under the same conditions as for Invention Product 64. Furthermore, for Invention Product 76, a third alternating laminate structure having the average thickness shown in Table 15 was formed on the surface of the lower layer under the same conditions as for Invention Product 51. For invention products 73 to 75, an alternating laminate structure was formed on the surface of the substrate as shown in Table 15. Specifically, for invention product 73, a third alternating laminate structure having an average thickness shown in Table 15 was formed on the surface of the substrate under the same conditions as for invention product 64. For invention products 74 to 75, an alternating laminate structure having an average thickness shown in Table 15 was formed on the surface of the substrate under the same conditions as for invention product 38.

[0105] Next, for Invention Products 67-68 and 72-76, after evacuation, the substrate was controlled until its temperature reached the temperature shown in Table 16 (the temperature at the start of film formation), and N2 gas was introduced into the reaction vessel, and the pressure inside the reaction vessel was adjusted to the pressure shown in Table 16. Thereafter, a bias voltage shown in Table 16 was applied to the substrate, and a metal evaporation source having the composition of the upper layer shown in Table 15 was evaporated by arc discharge with an arc current shown in Table 16, thereby forming an upper layer on the surface of the alternating laminate structure.

[0106] After forming the predetermined coating layer shown in Table 15 on the surface of the substrate, the heater was turned off, and after the sample temperature had dropped to 100°C or less, the sample was removed from the reaction vessel.

[0107] The average thickness and composition of each layer of the obtained sample were measured and calculated in the same manner as in Example 1. The results are shown in Tables 1, 9, 10, 11 and 15. Furthermore, the ratio (I(111) / I(200)) of the diffraction peak intensity (I(111)) of the cubic (111) plane to the diffraction peak intensity (I(200)) of the cubic (200) plane in the alternating laminate structure of the obtained sample was also measured and calculated in the same manner as in Example 1. The results are shown in Table 17. In this example, when the coating layer was made of the first alternating laminate structure, the peak intensities of the cubic (200) plane and the cubic (111) plane of the first alternating laminate structure were measured, and the ratio (I(111) / I(200)) of the diffraction peak intensity of the cubic (200) plane was calculated. structure and the second alternating stack structure The third alternating stack containing both structure In the case of , the third alternating stack structure The peak intensities of the cubic (200) and cubic (111) planes were measured. In addition, since the peaks of the first and second alternating stacked structures overlapped, the peaks were not separated, and the peak intensity including both reflections was calculated. In addition, during this measurement, the peaks of the alternating stacked structures were identified using the following methods (i) to (iii). (i) When the coating layer had an upper layer, the upper layer was removed by buffing to identify the peak of the alternating laminate structure. (ii) When the coating layer had a lower layer, the peak of the layer-by-layer structure was identified by thin film X-ray diffraction so as not to be affected by the lower layer. (iii) When the coating layer had an upper layer and a lower layer, the peak of the alternating laminate structure was identified by combining the above (i) and (ii).

[0108] [Table 15]

[0109] [Table 16]

[0110] [Table 17]

[0111] Using the obtained samples, cutting tests were carried out in the same manner as in Example 1 to evaluate the invention products. The results are shown in Table 18.

[0112] [Table 18]

[0113] The results shown in Table 18 show that the invention products including the underlayer and / or overlayer have better chipping and wear resistance and longer tool life. [Industrial Applicability]

[0114] The coated cutting tool of the present invention has excellent wear resistance and fracture resistance, and therefore can extend the tool life compared to conventional tools, and in this respect has high industrial applicability. [Explanation of symbols]

[0115] 1...Coated cutting tool, 2...Base material, 3...Coating layer, 4...First alternately laminated structure, 41...A layer, 42...B layer, 5...Second alternately laminated structure, 51...A layer, 52...C layer, 6...Third alternately laminated structure.

Claims

1. A coated cutting tool comprising a substrate and a coating layer formed on the substrate, the coating layer has a first alternating laminate structure in which two or more A layers and two or more B layers are alternately formed, The layer A contains a compound having a composition represented by the following formula (1): (Al a Cr b Ti 1-a-b )N (1) (In formula (1), a is the content ratio (atomic ratio) of Al element to the total of Al element, Cr element, and Ti element, 0.50≦a≦0.68 is satisfied, b is the content ratio (atomic ratio) of Cr element to the total content of Al element, Cr element, and Ti element, 0.02≦b≦0.30 is satisfied, 1-a-b is the content ratio (atomic ratio) of Ti element to the total content of Al element, Cr element, and Ti element, 0.11≦1−a−b≦0.40 is satisfied.) The layer B contains a compound having a composition represented by the following formula (2): (Al c Ti 1-c-d B d )N (2) (In formula (2), c is the content ratio (atomic ratio) of Al element to the total of Al element, Ti element, and B element, 0.30≦c≦0.64 is satisfied, d is the content ratio (atomic ratio) of the B element to the total content of the Al element, the Ti element, and the B element, 0.01≦d≦0.10 is satisfied, 1-cd is the content ratio (atomic ratio) of Ti element to the total content of Al element, Ti element, and B element, 0.30≦1−c−d≦0.69 is satisfied.) The average thickness of the first alternating laminate structure is 0.50 μm or more and 10.00 μm or less, an average thickness per layer of the A layer in the first alternating laminate structure is 2 nm or more and 300 nm or less; an average thickness per layer of the B layer in the first alternating laminate structure is 2 nm or more and 300 nm or less; Coated cutting tools.

2. a ratio ((1-a-b) / d) of the content ratio (atomic ratio) of Ti element in the A layer to the content ratio (atomic ratio) of B element in the B layer is 2.0 or more and 25.0 or less; The coated cutting tool of claim 1 .

3. an average value ((a+c) / 2) of the content ratio (atomic ratio) of Al element in the A layer and the content ratio (atomic ratio) of Al element in the B layer is 0.50 or more and 0.62 or less; The coated cutting tool according to claim 1 or 2.

4. the coating layer further has a second alternating laminate structure in which the A layer and the C layer are alternately formed in two or more layers, The C layer contains a compound having a composition represented by the following formula (3): (Al e Ti 1-e )N (3) (In formula (3), e is the content ratio (atomic ratio) of Al element to the total content of Al element and Ti element, 0.30≦e≦0.64 is satisfied, 1-e is the content ratio (atomic ratio) of Ti element to the total content of Al element and Ti element, 0.36≦1−e≦0.70 is satisfied.) The average thickness of the second alternating laminate structure is 0.50 μm or more and 5.00 μm or less, an average thickness per layer of the A layer in the second alternating laminate structure is 2 nm or more and less than 30 nm; an average thickness per layer of the C layer in the second alternate laminated structure is 2 nm or more and less than 30 nm; The coated cutting tool of claim 1 .

5. an average thickness per layer of the A layer in the first alternating laminate structure is 30 nm or more and 300 nm or less; an average thickness per layer of the B layer in the first alternating laminate structure is 30 nm or more and 300 nm or less; The coated cutting tool according to claim 1 or 2.

6. the coating layer has a third alternating laminate structure in which the first alternating laminate structure and the second alternating laminate structure are alternately formed three or more times in total, an average thickness per structure of the first alternating laminate structure in the third alternating laminate structure is 0.1 μm or more and 1.5 μm or less; an average thickness per structure of the second alternating laminate structure in the third alternating laminate structure is 0.1 μm or more and 1.5 μm or less; The coated cutting tool according to claim 4.

7. In X-ray diffraction of the first alternating stacked structure, the ratio (I(111) / I(200)) of the diffraction peak intensity (I(111)) of the cubic (111) plane to the diffraction peak intensity (I(200)) of the cubic (200) plane is 0.5 or more and 5.0 or less. The coated cutting tool according to claim 1 or 2.

8. In X-ray diffraction of the third alternating stack structure, the ratio (I(111) / I(200)) of the diffraction peak intensity (I(111)) of the cubic (111) plane to the diffraction peak intensity (I(200)) of the cubic (200) plane is 0.5 or more and 5.0 or less. The coated cutting tool according to claim 6.

9. the coating layer has an upper layer on a surface of the first alternating laminate structure opposite to the substrate, the upper layer is a single layer or multiple layers of a compound consisting of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y, and at least one element selected from the group consisting of C, N, O, and B (however, the composition of the compound constituting the upper layer is different from the composition of the compound constituting the layer of the first alternating laminated structure that is in contact with the upper layer); The average thickness of the upper layer is 0.01 μm or more and 2.00 μm or less. The coated cutting tool of claim 1 .

10. the coating layer has a lower layer between the substrate and the first alternating laminate structure, the lower layer is a single layer or multiple layers of a compound consisting of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y, and at least one element selected from the group consisting of C, N, O, and B (however, the composition of the compound constituting the lower layer is different from the composition of the compound constituting the layer of the first alternating laminated structure that is in contact with the lower layer); The average thickness of the lower layer is 0.01 μm or more and 2.00 μm or less. The coated cutting tool of claim 1 .

11. The coating layer has an upper layer on a surface opposite to the substrate in the third alternating laminate structure, the upper layer is a single layer or multiple layers of a compound consisting of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y, and at least one element selected from the group consisting of C, N, O, and B (however, the composition of the compound constituting the upper layer is different from the composition of the compound constituting the layer of the first alternating laminate structure or the second alternating laminate structure that is in contact with the upper layer); The average thickness of the upper layer is 0.01 μm or more and 2.00 μm or less. The coated cutting tool according to claim 6.

12. The coating layer has a lower layer between the substrate and the third alternating laminate structure, the lower layer is a single layer or multiple layers of a compound consisting of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, and Y, and at least one element selected from the group consisting of C, N, O, and B (however, the composition of the compound constituting the lower layer is different from the composition of the compound constituting the layer of the first alternating laminate structure or the second alternating laminate structure that is in contact with the lower layer); The average thickness of the lower layer is 0.01 μm or more and 2.00 μm or less. The coated cutting tool according to claim 6.

13. The average thickness of the entire coating layer is 0.5 μm or more and 10.0 μm or less. The coated cutting tool according to claim 1 or 2.

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