Coated Cutting Tools

Abstract

To provide a coated cutting tool having excellent chipping resistance and wear resistance and a long tool life. [Solution] A coated cutting tool includes a substrate and a coating layer, wherein the coating layer has a compound layer containing a cubic compound composed of at least one selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Al, Si, and B, and at least one selected from C, N, and O, the compound layer having an average thickness of 0.5 μm to 5.0 μm, and an angle α that shows a maximum intensity Ia in the range of 0° to 90° in an X-ray intensity distribution of the α axis of a pole figure for a (200) plane of the cubic crystal of the compound layer. a is 5° or more and 25° or less, and the angle α is 40° or more and 90° or less, and the angle α b is 40° or more and less than 60°, and the ratio of Ib to Ia (Ib / Ia) of the compound layer is 0.5 or more and less than 1.0.

Description

[Technical Field]

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

[0002] In recent years, with the increasing demand for high-efficiency cutting processes, cutting tools with longer tool life than ever before are required. Therefore, the required properties of tool materials, such as improved wear resistance and chipping resistance, which are related to the life of cutting tools, have become increasingly important. To improve these properties, coated cutting tools, which include a substrate made of cemented carbide, cermet, cubic boron nitride (cBN), or the like, and a coating layer covering the surface thereof, have been widely used.

[0003] As an example of a coated cutting tool, Patent Document 1 describes a coated tool including a substrate and a coating layer disposed on the substrate. Patent Document 1 specifically describes that the coating layer of the coated tool contains cubic crystals containing at least one element selected from the group 4, 5, and 6 elements of the periodic table, Al, Si, B, Y, and Mn, and at least one element selected from the group 1, 2, 3, and 4. Patent Document 1 further describes that the coating layer of the coated tool has, in an X-ray intensity distribution of the α-axis of a pole figure for the (200) plane of the cubic crystals, a first peak located between 15° and 30°, a second peak located between 60° and 75°, and a valley between the first and second peaks where the X-ray intensity is lower than that of the first and second peaks, and the peak intensity of the first peak is 0.7 times or more that of the second peak.

[0004] As an example of a coated cutting tool, Patent Document 2 describes a coated tool including a substrate and a coating layer located on the surface of the substrate. Patent Document 2 specifically describes that the coating layer contains cubic crystals consisting of at least one element selected from among elements of Groups 4a, 5a, and 6a of the periodic table, Al, Si, B, Y, and Mn, and at least one element selected from C and N. Patent Document 2 further describes that in the measurement range of 0° to 90° in the X-ray intensity distribution of the α-axis of a pole figure for the (111) plane of the coating layer of the coated tool, the difference between the maximum and minimum values ​​of X-ray intensity in the α-axis angle range of 30° to 90° is 10% or less of the maximum value. Furthermore, Patent Document 2 describes, as another example, that in the measurement range of 0° to 90° in the X-ray intensity distribution of the α-axis of a pole figure for the (200) plane of the coating layer of the coated tool, the X-ray intensity has maximum and minimum values ​​in the angle range of the α-axis of 0° to 50°, and the difference between the maximum and minimum values ​​is 10% or less of the maximum value. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 146711 [Patent Document 2] International Publication No. 2023 / 162682 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, cutting conditions have become stricter than ever before in order to improve machining efficiency. In addition, the increasing strength of workpiece materials has led to a demand for tools with improved chipping resistance and wear resistance.

[0007] Cast iron is sometimes machined using tools as a workpiece. There is also a trend toward higher strength in cast iron. When machining workpieces such as high-strength cast iron, the thermal and mechanical loads on the cutting edge are high, making chipping more likely to occur. In addition, chipping can sometimes lead to chipping. Therefore, it is difficult to extend the tool life when machining workpieces such as high-strength cast iron.

[0008] Patent Document 1 describes that a coated cutting tool has high hardness and excellent wear resistance due to the presence of a predetermined coating layer made of cubic crystals. However, the coated cutting tool described in Patent Document 1 has insufficient adhesion of the coating layer, so there is room for improvement in fracture resistance.

[0009] Patent Document 2 describes that the coating layer of a coated tool contains crystals of a predetermined cubic crystal structure, resulting in a homogeneous structure with a uniform crystal orientation. Patent Document 2 also describes that the coated tool can therefore suppress abnormal wear, such as chipping. However, the coated tool of Patent Document 2 is prone to chipping due to insufficient high-temperature strength, and there is room for improvement in fracture resistance. Furthermore, there is room for improvement in wear resistance due to insufficient hardness.

[0010] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a coated cutting tool that has excellent chipping resistance and wear resistance and a long tool life. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention has the following configuration.

[0012] (Configuration 1) Aspect 1 is a coated cutting tool including a substrate and a coating layer formed on the substrate, the coating layer has a compound layer containing a compound having a cubic crystal structure composed of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Al, Si, and B, and at least one element selected from the group consisting of C, N, and O; the compound layer has an average thickness of 0.5 μm or more and 5.0 μm or less, In the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer, when the maximum intensity in the range of 0° to 90° is defined as Ia, the angle α indicating Ia a is between 5° and 25°, In the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer, when the maximum intensity in the range of 40° to 90° is Ib, the angle α indicating Ib b is 40° or more and less than 60°, In the coated cutting tool, the ratio (Ib / Ia) of Ib to Ia of the compound layer is 0.5 or more and less than 1.0.

[0013] (Configuration 2) In the second configuration, the angle α indicating the Ib of the compound layer b and the angle α indicating the Ia a The difference between (α b -α a 2. The coated cutting tool of claim 1, wherein the angle between the outer circumferential surface and the outer circumferential surface is 20° or more and 40° or less.

[0014] (Configuration 3) In a third aspect, the compound layer has a composition represented by the following formula (1): (Al a Ti b M 1-a-b )X ···(1) the M is at least one element selected from the group consisting of Cr, Zr, Hf, V, Nb, Ta, Mo, W, Y, Si, and B; X is at least one element selected from the group consisting of C, N, and O, The value of a is 0.60 or more and 0.90 or less, The value of b is 0.08 or more and 0.40 or less, 3. The coated cutting tool of configuration 1 or 2, wherein the value of 1-ab is 0.00 or greater and 0.20 or less.

[0015] (Configuration 4) A configuration 4 is the coated cutting tool of any one of configurations 1 to 3, wherein the coating layer has an average thickness of 0.5 μm or more and 5.0 μm or less.

[0016] (Configuration 5) Aspect 5 is the coated cutting tool of any one of aspects 1 to 4, wherein the substrate is a cemented carbide, a cermet, a ceramic, or a cubic boron nitride sintered body. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a coated cutting tool having excellent chipping resistance and wear resistance and a long tool life. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a graph showing the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer of Invention Product 1. [Figure 2] 10 is a graph showing the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer of Comparative Product 3. FIG. [Figure 3] FIG. 1 is a schematic diagram showing the optical system of Schulz's reflection method. [Figure 4] This is a pole figure showing the positions of the α and β angles. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail. Note that the following embodiments are forms for realizing the present invention, and are not intended to limit the scope of the present invention.

[0020] <Coated cutting tools> The coated cutting tool of this embodiment includes a substrate and a coating layer formed on the substrate. Specific examples of the coated cutting tool include indexable cutting inserts for milling or turning, drills, and end mills.

[0021] <Base material> Examples of the substrate of the coated cutting tool of this embodiment include cemented carbide, cermet, ceramics, cubic boron nitride sintered body, diamond sintered body, and high-speed steel. The substrate of the coated cutting tool of this embodiment is preferably cemented carbide, cermet, ceramics, or cubic boron nitride sintered body. Among these, cemented carbide or cermet is more preferred because it has excellent fracture resistance and wear resistance.

[0022] The substrate may have a surface that has been modified. For example, if the substrate is a cemented carbide, a de-β layer may be formed on the surface. If the substrate is a cermet, a surface-hardened layer may be formed. The effects of this embodiment can be achieved even if the surface of the substrate of the coated cutting tool has been modified.

[0023] <Coating layer> The coating layer of the coated cutting tool of this embodiment has a predetermined compound layer. In this specification, the predetermined compound layer refers to a compound layer that contains a compound having a cubic crystal structure composed of predetermined elements, the compound layer has an average thickness within a predetermined range, and the X-ray intensity distribution of the α-axis of a pole figure for the (200) plane of the cubic crystal of the compound layer has a predetermined distribution (e.g., a distribution in which a predetermined maximum intensity falls within a predetermined angle range, also described below). In this specification, the coating layer of the coated cutting tool of this embodiment may be referred to as the "coating layer of this embodiment." The coating layer of this embodiment may have layers other than the predetermined compound layer. It is preferable that the coating layer of this embodiment consists solely of the predetermined compound layer.

[0024] The coated cutting tool of this embodiment includes a coating layer having a predetermined compound layer, so that the coated cutting tool has excellent chipping resistance and wear resistance and a long tool life.

[0025] The compound layer included in the coating layer of this embodiment can be a single compound layer. The compound layer included in the coating layer of this embodiment can be a compound layer with a structure in which multiple types of compound layers with different compositions are laminated. When the compound layer is a compound layer with multiple types of compound layers, the compound layer closest to the substrate may be referred to as the first compound layer, the second compound layer, etc., in this specification. In this specification, the "first compound layer" may be simply referred to as the "first layer." When multiple types of compound layers are laminated, the number of types of compound layers is preferably 1 to 5, and more preferably 1 to 3. Increasing the number of compound layers tends to extend the tool life. On the other hand, if there are too many types of compound layers, the manufacturing cost of the coated cutting tool may be high. When the compound layer is a compound layer with a structure in which multiple types of compound layers with different compositions are laminated, the average thickness of each layer may be, for example, 0.1 μm to 5.0 μm, or 0.2 μm to 3.0 μm.

[0026] The compound layer included in the coating layer of this embodiment may be a compound layer having a structure in which multiple types of compound layers with different compositions are alternately laminated. When the compound layer has a structure in which multiple types of compound layers are alternately laminated, the compound layer closest to the substrate may be referred to as the first compound layer, the second compound layer, etc., in this specification. In this specification, the "first compound layer" may be simply referred to as the "first layer." For example, when the compound layer has a structure in which the first and second layers are alternately laminated, the first and second layers may be considered as one pair of compound layers, and the compound layer may have a structure in which multiple pairs of compound layers are laminated. The same applies when one pair of compound layers has a structure of three or more layers. When the compound layer has a structure of three or more layers, the term "one set of compound layers" may be used instead of "one pair of compound layers." However, in this specification, the term "pair" may be used even when the compound layer has a structure of three or more layers, just as in the case of a two-layer structure. The number of types of compound layers included in one pair of compound layers is preferably 2 to 5, and more preferably 2 to 3. The tool life tends to be longer as the number of compound layers included in one pair of compound layers increases. On the other hand, if there are too many types of compound layers, the manufacturing cost of the coated cutting tool may increase.

[0027] The compound layer preferably has a structure in which multiple types of compound layers (one pair of compound layers) with different compositions are alternately laminated. Such a compound layer structure can prevent cracks generated during cutting from propagating toward the substrate, thereby further improving the chipping resistance of the coating layer. When the compound layer has a structure in which multiple types of compound layers with different compositions are alternately laminated, the average thickness per layer is preferably 2 nm to 1500 nm, more preferably 3 nm to 750 nm, and even more preferably 4 nm to 400 nm. A larger average thickness per layer tends to facilitate the formation of a layer with a uniform thickness. On the other hand, a smaller average thickness per layer tends to improve the adhesion between the layers, thereby suppressing peeling of the coating layer, thereby improving the chipping resistance of the coating layer. The number of pairs of compound layers is preferably 2 pairs to 1000 pairs, more preferably 2 pairs to 50 pairs, and even more preferably 2 pairs to 20 pairs.

[0028] The coating layer of the coated cutting tool of this embodiment has a compound layer containing a compound having a cubic crystal structure composed of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Al, Si, and B, and at least one element selected from the group consisting of C, N, and O. The inclusion of the predetermined compound in the compound layer of the coating layer results in excellent fracture resistance and wear resistance.

[0029] The average thickness of the compound layer of the coating layer of the coated cutting tool of this embodiment is 0.5 μm to 5.0 μm, preferably 0.6 μm to 4.8 μm, and more preferably 0.8 μm to 4.5 μm. The average thickness of the compound layer can be determined by measuring three points on a cross section of the coated cutting tool near a position 50 μm from the cutting edge toward the center of the rake face using a scanning electron microscope (SEM) and averaging the values ​​measured at the three points.

[0030] When the average thickness of the compound layer of the coating layer is 5.0 μm or less, peeling of the coating layer can be suppressed, resulting in excellent chipping resistance, while when the average thickness of the compound layer is 0.5 μm or more, excellent wear resistance can be achieved.

[0031] In the compound layer of the coating layer of the coated cutting tool of this embodiment, when the maximum intensity in the range of 0° to 90° in the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer is Ia, the angle α indicating Ia is a is between 5° and 25°. a is preferably 6° or more and 24° or less, and more preferably 8° or more and 23° or less.

[0032] Figure 1 shows the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer of Invention Product 1 in Example 1. In Figure 1, the maximum intensity Ia exists at an angle of 15° within the angle α range of 0° to 90°. Therefore, when the maximum intensity of the coating layer of Invention Product 1 within the angle α range of 0° to 90° is defined as Ia, the angle α at which Ia is shown is a is 15°.

[0033] Figure 2 shows the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer of Comparative Product 3. In Figure 2, the maximum intensity Ia is present at an angle of 37° within the angle α range of 0° to 90°. Therefore, when the maximum intensity Ia of the coating layer of Comparative Product 3 within the angle α range of 0° to 90° is defined as Ia, the angle α at which Ia is exhibited is a is 37°. Therefore, the angle α a is not in the range of 5° to 25°.

[0034] Angle α of the compound layer of the coating layer a When the angle α is 25° or less, the high-temperature strength is high and the occurrence of chipping is suppressed, resulting in excellent fracture resistance. In addition, the hardness of the coating layer is improved, resulting in excellent wear resistance. a When the angle is 5° or more, the toughness of the coating layer is improved, resulting in excellent fracture resistance.

[0035] In the compound layer of the coating layer of the coated cutting tool of this embodiment, when the maximum intensity in the α-axis of the pole figure for the (200) plane of the cubic crystal of the compound layer is Ib in the range of angle α of 40° to 90°, the angle α indicating Ib is b is 40° or more and less than 60°. b is preferably 42° or more and 58° or less, and more preferably 43° or more and 57° or less.

[0036] In the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer of Invention Product 1 in Example 1 shown in Figure 1, the maximum intensity (maximum value) Ib exists at an angle of 48° within the angle α range of 40° to 90°. Therefore, when the maximum intensity of the coating layer of Invention Product 1 within the range of 40° to 90° is Ib, the angle α at which Ib is shown is b is 48°.

[0037] In the X-ray intensity distribution of the α axis of the pole figure for the cubic (200) plane of the compound layer of Comparative Product 3 shown in Figure 2, no maximum value exists when the angle α is in the range of 40° to 90°. Above 40°, the X-ray intensity monotonically decreases as the angle α increases. Therefore, in the range of angle α being in the range of 40° to 90°, the X-ray intensity reaches its maximum value when the angle α is 40°. Therefore, in the case of Comparative Product 3 shown in Figure 2, when the angle α is in the range of 40° to 90°, the X-ray intensity reaches its maximum intensity Ib when the angle α is 40°. Therefore, when the maximum intensity in the compound layer of Comparative Product 3 when the angle α is in the range of 40° to 90° is Ib, the angle α at which Ib is reached is b is 40°.

[0038] Angle α of the compound layer of the coating layer b When the angle α is less than 60°, the toughness of the coating layer is improved, and therefore the fracture resistance is excellent. b When the angle is 40° or more, peeling of the coating layer is suppressed, and therefore, the chipping resistance is excellent.

[0039] In the compound layer of the coating layer of the coated cutting tool of this embodiment, the ratio of Ib to Ia of the compound layer (Ib / Ia) is 0.5 or more and less than 1.0, and preferably 0.51 or more and 0.97 or less.

[0040] When the ratio (Ib / Ia) of the compound layer of the coating layer is less than 1.0, the high-temperature strength of the coating layer is increased, and chipping is suppressed, resulting in excellent fracture resistance. Furthermore, the hardness is improved, resulting in excellent wear resistance. On the other hand, when the ratio (Ib / Ia) is 0.5 or more, peeling of the coating layer is suppressed, resulting in excellent fracture resistance.

[0041] The predetermined compound layer included in the coating layer of the coated cutting tool of this embodiment contains a compound having a cubic crystal structure made of the above-mentioned predetermined elements, the average thickness of the compound layer is within a predetermined range, and the angle α showing the above-mentioned maximum intensities Ia and Ib in the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer is a and α b is in the above-mentioned range and the ratio (Ib / Ia) is in the above-mentioned range, a coated cutting tool having excellent chipping resistance and wear resistance and a long tool life can be obtained.

[0042] The X-ray intensity distribution of the α-axis of the pole figure for the (200) plane of the cubic crystal of the compound layer of the coating layer of this embodiment can be measured by the Schulz reflection method. The Schulz reflection method uses an equiangular reflection optical system, in which the angle of incidence and the angle of reflection are both θ, with 2θ as the diffraction angle, as shown in FIG. 3. Specifically, as shown in FIG. 3, the Schulz reflection method measures the intensity distribution of the diffracted rays by changing the direction of the sample relative to the incident X-rays through α rotation around the A-axis in the sample plane and β rotation (i.e., in-plane rotation) around the normal to the sample plane (B-axis). When the B-axis is on the plane determined by the incident and diffracted rays, the α angle is defined as 90°. When the α angle is 90°, it corresponds to the center point on the pole figure, as shown in FIG. 4. As a specific measurement method, for example, the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer can be measured using a reciprocal lattice space mapping program of an X-ray diffractometer D8 Discover manufactured by Bulker Co., Ltd., according to the following measurement method and analysis conditions. Note that in this specification, the α angle may also be referred to as "angle α."

[0043] [Measurement method (Schulz reflection method)] (1) High-precision goniometer (2) Multipurpose sample stage (3) 2D detector Vantec-500 (4) Target: Cu, Voltage: 50 kV, Current: 1000 μA (5) Micro slit: 1 mm (6) UBC collimator: 0.5 mm

[0044] [Analysis conditions] (1) Fixed 2θ angle: The diffraction angle of the (200) plane of the cubic crystal of the compound layer used for analysis is the angle at which the diffraction intensity is highest between 42.0° and 44.5°. x When x -0.1° to 2θ x The range was set to +0.1°. (2) Alpha scanning range: 0 to 90 degrees (in 1 degree steps) (3) β fixed angle: 0°

[0045] The α angle showing the maximum intensity can also be read from the contour of the pole figure for the (200) plane of the cubic crystal of the compound layer. On the other hand, as shown in Figure 1, from the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer, the angle α showing the maximum intensity Ia in the range of 0° to 90° can be read. a , and the angle α showing the maximum intensity Ib in the range of 40° to 90° b can be easily obtained.

[0046] In the compound layer of the coating layer of the coated cutting tool of this embodiment, the angle α b and angle α a The difference between (α b -α a ) is preferably 20° or more and 40° or less, more preferably 24° or more and 38° or less, and even more preferably 27° or more and 36° or less.

[0047] In the compound layer of the coating layer, the difference (α b -α a When the difference (α ) is 40° or less, the toughness of the coating layer is improved, and therefore the fracture resistance tends to be excellent. b -α a ) is 20° or more, the angle α a By setting the angle to 25° or less, the effect of improving the hardness of the coating layer is further enhanced, and the coating layer tends to have excellent wear resistance.

[0048] The compound layer of the coating layer of the coated cutting tool of the embodiment may have a composition represented by the following formula (1). In formula (1), "Al" is aluminum and "Ti" is titanium. In formula (1), the symbol X is at least one element selected from carbon (C), nitrogen (N), and oxygen (O). The symbol M is at least one element selected from a predetermined group of elements described below. (Al a Ti b M 1-a-b )X ···(1)

[0049] In formula (1) representing the composition of the compound layer of the coating layer, the element represented by the symbol M (M element) is at least one element selected from the group consisting of Cr, Zr, Hf, V, Nb, Ta, Mo, W, Y, Si and B.

[0050] When the compound layer contains Cr as the M element in formula (1), the formation of hexagonal crystals in the coating layer is suppressed, and the hardness of the coating layer is improved, which tends to result in excellent wear resistance.

[0051] When the compound layer contains Nb, Ta, Mo and / or W as the M element in formula (1), the toughness of the coating layer is improved, and therefore the chipping resistance tends to be excellent.

[0052] When the compound layer contains Si and / or B as the M element in formula (1), the hardness of the coating layer is improved, and therefore the wear resistance tends to be excellent.

[0053] When the compound layer contains Cr, Zr, Hf, V and / or Y as the M element in formula (1), the oxidation resistance of the coating layer is improved, and therefore the wear resistance tends to be excellent.

[0054] In formula (1) representing the composition of the compound layer of the coating layer, the element represented by the symbol X (X element) is at least one element selected from the group consisting of C, N, and O. The X element is preferably at least one element selected from the group consisting of C and N, and more preferably N. When the compound layer of the coating layer contains a compound containing the X element, the coating layer has excellent chipping resistance and wear resistance.

[0055] In formula (1), the value of a, which is the content ratio (atomic ratio) of Al element to the total of Al element, Ti element, and M element, is preferably 0.60 or more and 0.90 or less, more preferably 0.67 or more and 0.89 or less, and even more preferably 0.73 or more and 0.88 or less.

[0056] In formula (1) representing the composition of the compound layer of the coating layer, when the value of a is 0.90 or less, the formation of hexagonal crystals in the coating layer is suppressed and the hardness is improved, so that the wear resistance tends to be excellent. On the other hand, when the value of a is 0.60 or more, the coating layer contains a large amount of Al element, so that the hardness and oxidation resistance of the coating layer are improved, so that the wear resistance tends to be excellent.

[0057] In formula (1) which represents the composition of the compound layer of the coating layer, by increasing the content ratio (atomic ratio) a of Al, the angle α a and angle α b can be made larger.

[0058] In formula (1), the value b, which is the content ratio (atomic ratio) of Ti element to the total of Al element, Ti element, and M element, is preferably 0.08 or more and 0.40 or less, more preferably 0.10 or more and 0.33 or less, and even more preferably 0.12 or more and 0.27 or less.

[0059] In formula (1) representing the composition of the compound layer of the coating layer, when the value of b is 0.40 or less, the coating layer contains a relatively large amount of Al element, which improves heat resistance and tends to have excellent wear resistance. Alternatively, the coating layer contains a relatively large amount of M element, which tends to have excellent wear resistance and / or fracture resistance. On the other hand, when the value of b is 0.08 or more, peeling of the coating layer is suppressed, which tends to have excellent fracture resistance.

[0060] In formula (1), the value of 1-ab, which is the content ratio (atomic ratio) of the M element to the total of the Al element, the Ti element, and the M element, is preferably 0.00 or more and 0.20 or less, more preferably 0.00 or more and 0.10 or less, even more preferably 0.00 or more and 0.05 or less, and still more preferably 0.00.

[0061] In formula (1), which represents the composition of the compound layer of the coating layer, when the value of 1-ab is 0.20 or less, the coating layer contains a relatively large amount of Al element and / or Ti element, which improves heat resistance, and therefore tends to have excellent wear resistance. Also, when the value of 1-ab is zero (when the M element is not contained), the coating layer contains a relatively large amount of Al element and / or Ti element, which improves heat resistance, and therefore tends to have excellent wear resistance. On the other hand, when the value of 1-ab is greater than zero (when the M element is contained), the coating layer tends to have excellent wear resistance and / or fracture resistance.

[0062] In the coated cutting tool of this embodiment, the average overall thickness of the coating layer is preferably 0.5 μm to 5.0 μm, more preferably 0.6 μm to 4.8 μm, and even more preferably 0.8 μm to 4.5 μm. The average thickness of the coating layer can be determined by measuring three locations on a cross section of the coated cutting tool near a position 50 μm from the cutting edge toward the center of the rake face using an SEM and averaging the values ​​at the three locations. When the coating layer consists of only a compound layer, the average overall thickness of the coating layer is the same as the average thickness of the compound layer.

[0063] When the total average thickness of the coating layer is 5.0 μm or less, peeling of the coating layer is suppressed, and thus chipping resistance tends to be improved, whereas when the total average thickness of the coating layer is 0.5 μm or more, wear resistance tends to be improved.

[0064] The coated cutting tool of this embodiment has the above-described predetermined coating layer, and thus has excellent chipping resistance and wear resistance, and can have a long tool life.

[0065] In Patent Document 1, when the maximum intensity in the range of angle α being 40° or more and 90° or less is defined as Ib in the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer, the angle α showing Ib is bOn the other hand, in the coated cutting tool of this embodiment, when the maximum intensity in the range of angle α being 40° or more and 90° or less is Ib in the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer, the angle α showing Ib is b The coated cutting tool of this embodiment is characterized in that the angle α indicating Ib is 40° or more and less than 60°. b is 40° or more, peeling of the coating layer is suppressed. Therefore, the coating layer of this embodiment has superior chipping resistance compared to the coated tool described in Patent Document 1. Furthermore, the coated cutting tool of this embodiment has an angle α b When the angle is less than 60°, the toughness of the coating layer is improved, and therefore, the coating layer of this embodiment has superior fracture resistance compared to the coated tool described in Patent Document 1.

[0066] In Patent Document 2, when the maximum intensity in the range of angle α between 0° and 90° in the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer is defined as Ia, the angle α showing Ia is a On the other hand, the coated cutting tool of this embodiment has an angle α a The coated cutting tool of this embodiment is characterized in that the angle α indicating Ia is 5° or more and 25° or less. a When the angle Ia is 5° or more, the toughness of the coating layer is improved. Therefore, the coating layer of this embodiment has superior fracture resistance compared to the coated tool described in Patent Document 2. The coated cutting tool of this embodiment has an angle Ia of 25° or less, which provides the following advantages compared to the coated tool described in Patent Document 2. That is, the coated cutting tool of this embodiment has improved toughness of the coating layer, and therefore has superior fracture resistance. Furthermore, the coated cutting tool of this embodiment has high high-temperature strength of the coating layer, which suppresses the occurrence of chipping, and therefore has superior fracture resistance. Furthermore, the coated cutting tool of this embodiment has improved hardness, and therefore has superior wear resistance of the coating layer.

[0067] Furthermore, Patent Document 2 does not disclose that, in the X-ray intensity distribution of the α axis of a pole figure for the (200) plane of the cubic crystal of the compound layer, when the maximum intensity in the angle α range of 0° to 90° is Ia and the maximum intensity in the angle α range of 40° to 90° is Ib, the ratio (Ib / Ia) of the compound layer is 0.5 or more and less than 1.0. On the other hand, the coated cutting tool of this embodiment is characterized in that the ratio (Ib / Ia) of the compound layer is 0.5 or more and less than 1.0. The coated cutting tool of this embodiment has a ratio (Ib / Ia) of 0.5 or more, which suppresses peeling of the coating layer. Therefore, the coating layer of this embodiment has superior fracture resistance compared to the coated tool described in Patent Document 1. The coated cutting tool of this embodiment has a ratio (Ib / Ia) of less than 1.0, which provides the following advantages compared to the coated tool described in Patent Document 2. That is, in the coated cutting tool of this embodiment, the high-temperature strength of the coating layer is increased, and the occurrence of chipping is suppressed, so the coating layer of this embodiment has excellent fracture resistance. Also, in the coated cutting tool of this embodiment, the hardness of the coating layer is improved, so the coating layer of this embodiment has excellent wear resistance.

[0068] <Method for forming coating layer> The method for forming (manufacturing) the compound layer of the coating layer in the coated cutting tool of this embodiment is not particularly limited. Examples of methods for forming the compound layer include physical vapor deposition methods such as ion plating, arc ion plating, sputtering, and ion mixing. Forming a coating layer using a physical vapor deposition method can form a sharp edge. Therefore, physical vapor deposition is preferred for forming the compound layer. Among these methods, arc ion plating can provide better adhesion between the coating layer and the substrate. Therefore, arc ion plating is more preferred for forming the compound layer.

[0069] The compound layer included in the coating layer of this embodiment can be a compound layer having a structure in which multiple types of compound layers with different compositions are laminated. For example, when the compound layer has a structure in which two compound layers with different compositions are laminated, the compound layer can consist of a first compound layer and a second compound layer. In this case, each of the multiple types of compound layers with different compositions can be formed by the following method. Also, one compound layer (for example, the first compound layer) can be formed in multiple steps.

[0070] <Method of manufacturing a coated cutting tool> 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 of this embodiment.

[0071] First, the substrate processed into the tool shape is placed in a reaction vessel of a physical vapor deposition apparatus, and a metal evaporation source is installed in the reaction vessel. The element contained in the metal evaporation source is at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Al, Si, and B. Then, the pressure in the reaction vessel is increased to 1.0 × 10 -2 The reactor is evacuated to a vacuum of 100 Pa or less, and the substrate is heated using a heater inside the reactor until its temperature reaches 200°C or higher and 700°C or lower. After heating, Ar gas is introduced into the reactor to set the pressure inside the reactor to 0.5 Pa or higher and 5.0 Pa or lower. In an Ar gas atmosphere with a pressure of 0.5 Pa or higher and 5.0 Pa or lower, a bias voltage of -500 V or higher and -350 V or lower is applied to the substrate, and a current of 40 A or higher and 50 A or lower is passed through the tungsten filament inside the reactor, to perform an ion bombardment treatment using Ar gas on the surface of the substrate. After performing the ion bombardment treatment 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.

[0072] When forming the compound layer of the coating layer used in this embodiment, the temperature of the substrate is controlled so that the temperature of the substrate reaches a predetermined starting temperature. After this control, gas is introduced into the reaction vessel to adjust the pressure inside the reaction vessel to 3.0 Pa or more and 8.0 Pa or less. For example, when the compound layer of the coating layer contains carbon (C), the gas to be introduced may be C2H2 gas. When the compound layer of the coating layer contains nitrogen (N), the gas to be introduced may be N2 gas. When the compound layer of the coating layer contains oxygen (O), the gas to be introduced may be O2 gas. When the compound layer of the coating layer contains at least two selected from carbon (C), nitrogen (N), and oxygen (O), the gas to be introduced may be a mixed gas of the above-mentioned gases. For example, when the compound layer of the coating layer contains N and C, the gas to be introduced may be a mixed gas of N2 gas and C2H2 gas.

[0073] For example, when the compound layer of the coating layer contains nitrogen (N) and carbon (C), 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.

[0074] When forming a compound layer of the coating layer containing carbon (C), a metal evaporation source containing carbon (C) can be used as needed.

[0075] Next, a bias voltage of -600 V to -250 V, preferably -550 V to -300 V, is applied to the substrate, and a metal evaporation source appropriate for the metal and non-metallic components of each layer is evaporated by arc discharge with an arc current of 50 A to 250 A, preferably 80 A to 200 A, to form a compound layer of the coating layer. At this time, the temperature of the substrate is increased and changed at a constant gradient from a predetermined starting temperature to a predetermined final temperature, and the compound layer of the coating layer can be formed. In this manner, the compound layer can be formed.

[0076] In the manufacturing method of a coated cutting tool according to this embodiment, one compound layer (e.g., the first compound layer) can be formed in multiple steps. In this specification, the number of times a compound layer is formed in multiple steps is referred to as the "number of cycles." Therefore, the formation of the compound layer described above can be one or more cycles of forming a predetermined compound layer. When the compound layer is formed in multiple cycles, after the first cycle, the temperature of the substrate is cooled to a predetermined starting temperature. During this cooling period, the formation of the compound layer is suspended. Once the temperature of the substrate reaches the predetermined starting temperature, the formation of the next second cycle begins. At this time, the compound layer in the second cycle can be formed by increasing the temperature of the substrate at a constant gradient from the predetermined starting temperature to the predetermined final temperature, as in the first cycle described above. By repeating the above procedure, the compound layer can be formed a predetermined number of cycles.

[0077] When the compound layer has a structure in which two compound layers with different compositions are laminated, the first compound layer can be formed for a predetermined number of cycles, and then the second compound layer can be formed for a predetermined number of cycles in the same procedure as for the first layer. The same applies to a compound layer having a structure in which three or more compound layers with different compositions are laminated.

[0078] The starting temperature when forming the compound layer of the coating layer is preferably 200° C. or higher and 550° C. or lower, more preferably 250° C. or higher and 520° C. or lower, and even more preferably 300° C. or higher and 480° C. When multiple cycles are performed to form one layer, the starting temperature for each cycle is preferably the same.

[0079] The temperature reached when forming the compound layer of the coating layer is higher than the above-mentioned starting temperature. The temperature reached is preferably 400°C or higher and 700°C or lower, more preferably 450°C or higher and 650°C or lower, and even more preferably 480°C or higher and 620°C or lower. When multiple cycles are performed to form one layer, the temperature reached in each cycle is preferably the same.

[0080] When forming the compound layer of the coating layer, the thickness of the compound layer formed from a predetermined starting temperature to a predetermined reached temperature (thickness of the compound layer in one cycle) is preferably 10 nm to 1000 nm, more preferably 50 nm to 800 nm, and even more preferably 100 nm to 600 nm. When forming multiple cycles to form one layer, it is preferable that the thickness of the compound layer in each cycle is the same.

[0081] The number of cycles (number of formations) when forming one layer of a predetermined composition of the compound layer of the coating layer is preferably 1 to 60 cycles, more preferably 2 to 55 cycles.

[0082] When the compound layer of the coating layer consists of two compound layers (first and second layers) with different compositions, an alternating laminate structure can be formed in which the first and second layers are alternately stacked in two or more layers. In this case, the first layer is formed under the film formation conditions for the first layer, and the second layer is formed under the film formation conditions for the second layer. Each layer can be formed alternately by alternately evaporating a metal evaporation source corresponding to the metal components of the first layer and a metal evaporation source corresponding to the metal components of the second layer by arc discharge under predetermined conditions. The thickness of each layer constituting the alternating laminate structure can be controlled by adjusting the metal evaporation source, starting temperature, and final temperature corresponding to the metal components of the first layer and the metal evaporation source, starting temperature, and final temperature corresponding to the metal components of the second layer, respectively.

[0083] In the coated cutting tool of this embodiment, in the step of forming the compound layer, the X-ray intensity distribution of the compound layer can be made into a predetermined shape by controlling manufacturing parameters such as pressure, starting temperature, final temperature, thickness per cycle, and bias voltage applied to the substrate. The influence of each manufacturing parameter on the compound layer will be described below.

[0084] When forming the compound layer, the starting temperature is lowered to reduce the angle α a and angle α bcan be reduced and the ratio (Ib / Ia) can be increased.

[0085] When forming the compound layer, the angle α b and the difference (α b -α a ) can be increased.

[0086] When forming the compound layer, the ratio (Ib / Ia) can be increased by increasing the thickness per cycle.

[0087] When forming the compound layer, the pressure is increased to increase the angle α a can be increased, and the difference (α b -α a ) can be made smaller.

[0088] When forming the compound layer, the bias voltage applied to the substrate is reduced to reduce the angle α b and angle α a It should be noted that "reducing the bias voltage applied to the substrate" means increasing the bias voltage in the negative direction (i.e., when the bias voltage has a negative value, increasing the absolute value of the negative value).

[0089] 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 located 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.

[0090] 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. [Example]

[0091] The present invention will be specifically described below using examples, but the present invention is not limited thereto. In the following examples, the coating layer does not include any layer other than the compound layer. Therefore, the compound layer may be referred to as the coating layer.

[0092] Example 1 Samples of invention products 1 to 23 were prepared as Example 1. Furthermore, as comparative examples (comparative example 1) for invention products 1 to 23, comparative products 1 to 11 were prepared.

[0093] <Manufacturing method> As the substrate for invention products 1 to 23 and comparison products 1 to 11, a cemented carbide alloy with a composition of 86.1% WC-12.0% Co-1.1NbC-0.8% Cr3C2 (all mass %) processed into the shape of an insert, SWMT13T3AFPR-MJ (manufactured by Tungaloy Corporation), was prepared. A metal evaporation source was placed in the reaction chamber of an arc ion plating device so as to obtain the compound layer composition shown in Table 1. The prepared substrate was fixed to a fixture on a rotary table in the reaction chamber to form a coating layer.

[0094] The compound layer of Example 1 shown in Table 1 has a composition represented by the following formula (1). In the compound layers of invention products 15 to 23 of Example 1, the element represented by symbol M in formula (1) was an element shown in the "M species" column of Table 1. In the compound layer of Example 1, nitrogen (N) was used as the element represented by symbol X in formula (1). (Al a Ti b M 1-a-b )X ···(1)

[0095] Then, the pressure in the reaction vessel was increased to 5.0 × 10 -3The reactor was evacuated to a vacuum of 100 Pa or less. After evacuating, the substrate was heated using a heater inside the reactor until the temperature reached 450°C. After heating, Ar gas was introduced into the reactor so that the pressure was 2.7 Pa. The substrate was heated until its temperature reached the starting temperature shown in Table 2.

[0096] 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.

[0097] Next, a first-cycle compound layer was formed on the surface of the substrate of Invention Products 1 to 23 and Comparative Products 1 to 11. Specifically, after evacuation, the temperature of the substrate was controlled to the starting temperature shown in Table 2. Nitrogen gas (N2) was introduced into the reaction vessel, and the pressure inside the reaction vessel was adjusted to the pressure shown in Table 2. Then, the bias voltage shown in Table 2 was applied to the substrate, and the metal evaporation source for the compound layer having the composition shown in Table 1 was evaporated by arc discharge with the arc current shown in Table 2, forming a first-cycle compound layer on the surface of the substrate. During compound layer formation, the pressure inside the reaction vessel was controlled to be as shown in Table 2. The arc discharge time for each cycle was adjusted to control the thickness of the compound layer in the first cycle to the thickness shown in the "Thickness per Cycle" column in Table 2. The compound layer was formed while the temperature of the substrate was changed at a constant gradient so that the temperature of the substrate was the starting temperature shown in the "Start Temperature" column of Table 2 at the start of compound layer formation in the first cycle and the reaching temperature shown in the "Attained Temperature" column of Table 2 at the end of compound layer formation in the first cycle. In this manner, a compound layer was formed on the surface of the substrate in the first cycle.

[0098] The formation of the compound layer was repeated the number of times indicated in the "Number of Cycles" column of Table 2. After forming the first-cycle compound layer on the surface of the substrate, the formation of the compound layer was stopped, and the temperature of the substrate was cooled to the starting temperature shown in Table 2. Then, in the same manner as the first-cycle compound layer formation process described above, the second-cycle compound layer was formed on the surface of the substrate. By repeating this process the number of times indicated in the "Number of Cycles" column of Table 2, a compound layer with a predetermined number of cycles was formed.

[0099] As shown in Table 2, the "starting temperature" and "arrival temperature" of Comparative Product 5 are the same. In this case, the temperature of the substrate when forming the compound layer was kept constant, and a compound layer with a thickness of 3000 nm was formed in one cycle.

[0100] When forming the compound layers of Invention Products 1 to 23, Comparative Products 1 to 4, and 5 to 11, the film-forming conditions for the predetermined number of cycles were all made the same. Therefore, the film-forming time for each cycle when forming the respective compound layers of Invention Products 1 to 23, Comparative Products 1 to 4, and 5 to 11 is constant.

[0101] After forming the compound layer on the surface of the substrate to the predetermined number of cycles and the predetermined average thickness shown in Table 2, the power of the heater was turned off, and after the sample temperature dropped below 100°C, the sample was taken out from the reaction vessel.

[0102] As described above, the coated cutting tools of Invention Products 1 to 23 and Comparative Products 1 to 11 were manufactured.

[0103] <Measurement of the average thickness of the compound layer> For the average thickness of the compound layer of each invention product and comparative product, a cross-section in the vicinity of a position 50 μm from the cutting edge of the coated cutting tool toward the center of the rake face was measured at three locations by SEM, and the average value of the three locations was taken as the average thickness. Table 1 shows the average thickness of the compound layer of each invention product and comparative product. Also, Table 2 shows the thickness per cycle of the coating layer. The value described in the "Thickness per Cycle" column of Table 2 is the value obtained by dividing the average thickness of the entire compound layer by the number of cycles.

[0104] <Measurement of the X-ray intensity distribution> The obtained samples were subjected to X-ray diffraction measurements using the 2θ / θ method using a Bluker D8 Discoer X-ray diffractometer. The measurement conditions were a tube voltage of 50 kV, a tube current of 1000 μA, a CuKα X-ray source, a 1 mm microslit, a 0.5 mm UBC collimator, and a 2θ measurement range of 10° to 140°. The crystal structure of the compound in the compound layer (coating layer) of all samples was confirmed to be a cubic NaCl-type structure. Furthermore, the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer was measured using the measurement method and analysis conditions described below.

[0105] [Measurement method (Schulz reflection method)] (1) High-precision goniometer (2) Multipurpose sample stage (3) 2D detector Vantec-500 (4) Target: Cu, Voltage: 50 kV, Current: 1000 μA (5) Micro slit: 1 mm (6) UBC collimator: 0.5 mm

[0106] [Analysis conditions] (1) Fixed 2θ angle: The diffraction angle of the (200) plane of the cubic crystal of the compound layer used for analysis is the angle at which the diffraction intensity is highest between 42.0° and 44.5°. x When x -0.1° to 2θ x The range was set to +0.1°. (2) α scanning range: 0° to 90° (1° step) (3) β fixed angle: 0°

[0107] Based on the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer of each sample measured as described above, the maximum intensity Ia in the range of 0° to 90° and the angle α at which Ia is a , the maximum intensity Ib in the α angle range of 40° to 90°, and the angle α at which Ib is b The value of the angle α a , and the angle α indicating Ibb The values ​​of the angle α for each sample in Example 1 are shown in Table 3. b and angle α a The difference between (α b -α a ), and the ratio of Ia to Ib (Ib / Ia).

[0108] <Measurement of the composition of each layer> The composition of the compound layer of each of the inventive and comparative products in Example 1 was measured by measuring the cross section of a specific layer of the coated cutting tool using an energy dispersive X-ray spectrometer (EDS). The crystal system of the compound layer was identified by X-ray diffraction measurement using a 2θ / θ focusing optical system. Table 1 shows the composition of the compound layer of each of the inventive and comparative products (the type and content ratio of elements contained in each layer).

[0109] <Cutting test> A cutting test was carried out on the coated cutting tools of the invention and the comparative example of Example 1, and the chipping resistance (tool life) was evaluated.

[0110] The cutting test conditions are as follows: [Cutting test conditions] Work material: FCD600 Workpiece shape: 200mm x 100mm x 60mm plate Cutting speed: 180m / min Cutting width: 100mm Cutting depth: 2.0 mm Feed per tooth: 0.25mm / tooth Coolant: Not used Evaluation items: The tool life was defined as the machining time until the tool flank wear width exceeded 0.3 mm or the cutting edge was chipped, and the machining time until the tool life was reached was measured. In addition, the form of damage at the end of the tool life was observed using an SEM.

[0111] Table 4 shows the results of the cutting test of the invention product and the comparative product of Example 1.

[0112] Example 2 As Example 2, samples of invention products 24 to 29 were prepared. In Example 2, multiple types of compound layers were laminated as the coating layer. As shown in Table 7, invention products 24, 26, and 27 had a coating layer consisting of two types of compound layers (first layer and second layer). Invention product 25 had a coating layer consisting of three types of compound layers (first layer, second layer, and third layer).

[0113] As shown in Table 5, in Example 2, compound layers of six types A to F were used. The method for measuring the composition of the compound layer of each invention product in Example 2 was the same as the method for measuring the composition of the compound layer of the sample in Example 1.

[0114] The compound layers of types A to F of Example 2 shown in Table 5 have compositions represented by the following formula (1). In the compound layer of type F of Example 2, the element represented by symbol M in formula (1) was the element (W) shown in the "M type" column of Table 5. In the compound layers of types A to F of Example 2, nitrogen (N) was used as the element represented by symbol X in formula (1), as in Example 1. (Al a Ti b M 1-a-b )X ···(1)

[0115] Table 6 shows the film formation conditions for the compound layers of types A to F. The compound layers of types A to F were formed according to the conditions shown in Table 6 in the same manner as the compound layer of the sample of Example 1 was formed.

[0116] The "Type" column in Tables 7 and 8 indicates which of Types A to F in Table 5 the compound layers (first, second and third layers) used in Inventions 24 to 29 correspond to.

[0117] The first layer of Invention Products 24 to 27 is the compound layer closest to the substrate. In Invention Products 24 to 27, the second layer was formed after the first layer was formed. In Invention Product 25, the third layer was further formed after the second layer was formed. For Invention Products 24 to 27, the "Average Thickness" column in Table 7 shows the average thickness of each compound layer (first layer, second layer, or third layer). For example, in Invention Product 24, the average thickness of the entire first layer formed in 4 cycles is 0.8 μm, and the average thickness of the entire second layer formed in 14 cycles is 2.8 μm.

[0118] In Invention Product 28 shown in Table 8, a compound layer was formed by alternately repeating six times (six pairs) a first layer formed in two cycles and a second layer formed in one cycle. For Invention Product 28, the "Number of cycles per pair" and "Average thickness per pair" columns in Table 8 show the number of cycles and average thickness per pair of each compound layer (first layer or second layer). For example, Invention Product 28 alternately formed a first layer with two cycles per pair and an average thickness of 0.4 μm per pair, and a second layer with one cycle per pair and an average thickness of 0.2 μm per pair. The average total thickness of the compound layers for Invention Product 28, including the first and second layers per pair, was 0.6 μm (= 0.4 μm + 0.2 μm), and the average thickness of the entire six pairs of compound layers was 3.6 μm (= 0.6 μm × 6 pairs).

[0119] In Invention Product 29 shown in Table 8, a compound layer was formed by alternately repeating 15 times (15 pairs) a first layer formed in one cycle and a second layer formed in one cycle. For example, in Invention Product 29, a first layer with an average thickness of 0.2 μm per pair was formed by one cycle per pair, and a second layer with an average thickness of 0.06 μm per pair was formed by alternating one cycle per pair. The combined average thickness of the first and second layers per pair in Invention Product 29 was 0.26 μm (= 0.2 μm + 0.06 μm), and the average thickness of the entire compound layer for a total of 15 pairs was 3.9 μm (= 0.26 μm × 15 pairs).

[0120] The average thickness of the entire compound layer (first and second layers, or first to third layers) is shown in the "Average Thickness of the Entire Compound Layer" column in Tables 7 and 8. The method for measuring the average thickness of the compound layer in the sample of Example 2 was the same as that in the sample of Example 1.

[0121] The X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer of the invention of Example 2 was measured under the same conditions as in Example 1. Based on the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer of each sample, the maximum intensity Ia in the range of 0° to 90° and the angle α showing Ia were calculated. a , the maximum intensity Ib in the α angle range of 40° to 90°, and the angle α at which Ib is b The value of the angle α a , and the angle α indicating Ib b In addition, Table 9 shows the values ​​of the angle α b and angle α a The difference between (α b -α a ), and the ratio of Ib to Ia (Ib / Ia).

[0122] As in Example 1, a cutting test was conducted on the coated cutting tool of the invention in Example 2 to evaluate the tool life. Table 10 shows the results of the cutting test on the invention in Example 2.

[0123] <Evaluation of cutting test> In the cutting tests of Examples 1 and 2, the tool life of the inventive product of this embodiment was 42 minutes or more, which was longer than the tool life of all the comparative products. Therefore, it can be said that the inventive product of this embodiment is a coated cutting tool with excellent chipping resistance and wear resistance and a long tool life.

[0124] On the other hand, in the cutting test of Example 1, all of the comparative products had a tool life of 36 minutes or less. Furthermore, in the cutting test, the damage type at the end of the tool life of comparative products 1 and 3 to 11 was chipping.

[0125] From the above, it is clear that the coated cutting tool of this embodiment has excellent chipping resistance and wear resistance, and is a coated cutting tool with a long tool life.

[0126] [Table 1]

[0127] [Table 2]

[0128] [Table 3]

[0129] [Table 4]

[0130] [Table 5]

[0131] [Table 6]

[0132] [Table 7]

[0133] [Table 8]

[0134] [Table 9]

[0135] [Table 10]

Claims

1. A coated cutting tool comprising a substrate and a coating layer formed on the substrate, the coating layer has a compound layer containing a compound having a cubic crystal structure composed of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Al, Si, and B, and at least one element selected from the group consisting of C, N, and O; the compound layer has an average thickness of 0.5 μm or more and 5.0 μm or less, In the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer, when the maximum intensity in the range of 0° to 90° is defined as Ia, the angle α indicating Ia ａ is 5° or more and 25° or less, In the X-ray intensity distribution of the α axis of the pole figure for the (200) plane of the cubic crystal of the compound layer, when the maximum intensity in the range of 40° to 90° is defined as Ib, the angle α indicating Ib is ｂ is equal to or greater than 40° and less than 60°, a ratio (Ib / Ia) of Ib to Ia of the compound layer is 0.5 or more and less than 1.0, The compound layer has a composition represented by the following formula (1): (Ala Ti b M 1-ab)X...(1) M is at least one element selected from the group consisting of Cr, Zr, Hf, V, Nb, Ta, Mo, W, Y, Si, and B; X is at least one element selected from the group consisting of C, N, and O, the value of a is 0.73 or more and 0.90 or less, A coated cutting tool, wherein the value of b is 0.08 or greater and 0.27 or less.

2. The angle α indicating the Ib of the compound layer ｂ and the angle α indicating the Ia ａ The difference between ｂ -α ａ 2. The coated cutting tool according to claim 1, wherein the angle between the first and second poles is 20° or greater and 40° or less.

3. 3. The coated cutting tool according to claim 1, wherein the value of 1-a-b is equal to or greater than 0.00 and equal to or less than 0.

12.

4. 3. The coated cutting tool according to claim 1, wherein the coating layer has an average thickness of 0.5 μm or more and 5.0 μm or less.

5. 3. The coated cutting tool according to claim 1, wherein the substrate is made of cemented carbide, cermet, ceramics or cubic boron nitride sintered body.

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