Cutting tool

Abstract

A cutting tool comprising a base member and a coating film disposed on the base member, wherein the coating film includes a first layer formed of Ti1-a-bAlaScbN, in which a is 0.35-0.65 and b is 0.01-0.10.

Description

Cutting tool

[0001] The present disclosure relates to a cutting tool.

[0002] Conventionally, a cutting tool including a base material and a coating disposed on the base material has been used for cutting (Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2015-54995

[0004] The cutting tool of the present disclosure is a cutting tool including a base material and a coating disposed on the base material, wherein the coating is Ti １－ａ－ｂ Al ａ Sc ｂ a cutting tool including a first layer composed of N, wherein a is 0.35 or more and 0.65 or less, and b is 0.01 or more and 0.10 or less.

[0005] FIG. 1 is a schematic diagram of an example of a cutting tool. FIG. 2 is a schematic enlarged cross-sectional view of an example of the cutting tool according to Embodiment 1. FIG. 3 is a schematic enlarged cross-sectional view of another example of the cutting tool according to Embodiment 1. FIG. 4 is a schematic enlarged cross-sectional view of another example of the cutting tool according to Embodiment 1. FIG. 5 is a schematic enlarged cross-sectional view of an example of the cutting tool according to Embodiment 2.

[0006] [Problems to be Solved by the Present Disclosure] From the viewpoint of cost reduction, a cutting tool having a long tool life is required even when machining difficult-to-cut materials such as nickel-based alloys.

[0007] Therefore, an object of the present disclosure is to provide a cutting tool having a long tool life even when machining difficult-to-cut materials such as nickel-based alloys.

[0008] [Effects of the Present Disclosure] According to the present disclosure, it is possible to provide a cutting tool having a long tool life even when machining difficult-to-cut materials such as nickel-based alloys.

[0009] [Description of Embodiments of the Present Disclosure] First, the embodiments of the present disclosure will be listed and described. (1) The cutting tool of the present disclosure is a cutting tool including a base material and a coating disposed on the base material, wherein the coating is Ti １－ａ－ｂ Al ａ Sc ｂA cutting tool comprising a first layer made of N, wherein a is 0.35 or more and 0.65 or less, and b is 0.01 or more and 0.10 or less.

[0010] According to the present disclosure, it is possible to provide a cutting tool having a long tool life even when machining a difficult-to-cut material such as a nickel-based alloy.

[0011] (2) In the above (1), the thickness of the first layer may be 0.3 μm or more and 15.0 μm or less. According to this, the tool life is further improved.

[0012] (3) In the above (1) or (2), the coating further includes a second layer disposed between the base material and the first layer, and the second layer is made of a compound composed of titanium and at least one element selected from the group consisting of carbon, nitrogen, and oxygen, and the thickness of the second layer may be 10 nm or more and 100 nm or less.

[0013] According to this, the adhesion between the base material and the first layer is improved, peeling of the first layer during use of the cutting tool is suppressed, and the tool life is further improved.

[0014] (4) In any one of the above (1) to (3), the coating further includes a third layer provided on the side of the first layer opposite to the base material, the third layer is made of TiCN or TiAlScCN, and the thickness of the third layer may be 0.1 μm or more and 1.0 μm or less.

[0015] Since the carbonitride has excellent sliding characteristics, when the third layer is present on the surface side of the coating, the sliding property of the coating is improved during machining of a difficult-to-cut material such as a nickel-based alloy. As a result, the cutting point is less likely to become high temperature, and the load applied to the tool is reduced, thereby further improving the tool life.

[0016] (5) The cutting tool of the present disclosure is a cutting tool including a base material and a coating disposed on the base material, and the coating is Ti １－ｃ－ｄ－ｅ Al ｃ Sc ｄ M ｅA cutting tool comprising an A layer made of N, wherein M is boron and / or silicon, c is 0.35 or more and 0.65 or less, d is 0.01 or more and 0.10 or less, and e is 0.01 or more and 0.05 or less.

[0017] According to this disclosure, it is possible to provide cutting tools that have a long tool life even when machining difficult-to-machine materials such as nickel-based alloys.

[0018] (6) In (5) above, the thickness of layer A may be 0.3 μm or more and 15.0 μm or less. This further improves tool life.

[0019] (7) In the above (5) or (6), the coating further comprises a B layer disposed between the substrate and the A layer, wherein the B layer is made of a compound of titanium and at least one element selected from the group consisting of carbon, nitrogen, and oxygen, and the thickness of the B layer may be 10 nm or more and 100 nm or less.

[0020] According to this, the adhesion between the substrate and layer A is improved, peeling of layer A during the use of cutting tools is suppressed, and tool life is further improved.

[0021] (8) In any of (5) to (7) above, the coating further includes a C layer provided on the side of the A layer opposite to the substrate, the C layer is made of TiCN or TiAlScMCN, the M is boron and silicon or both, and the thickness of the C layer may be 0.1 μm or more and 1.0 μm or less.

[0022] Because carbonitrides have excellent sliding properties, the presence of a C layer on the surface side of the coating improves the sliding properties of the coating when machining difficult-to-cut materials such as nickel-based alloys. This reduces the temperature at the cutting point and the load on the tool, further improving tool life.

[0023] [Details of Embodiments of the Disclosure] Specific examples of the cutting tools of the Disclosure will be described below with reference to the drawings. In the drawings of the Disclosure, the same reference numerals indicate the same part or a corresponding part. In addition, dimensional relationships such as length, width, thickness, and depth have been modified as appropriate for clarity and simplification of the drawings and do not necessarily represent actual dimensional relationships.

[0024] In this disclosure, the notation "A to B" means A or greater and B or less. If no unit is specified for A, and only a unit is specified for B, then the unit for A and the unit for B are the same.

[0025] In this disclosure, when compounds and the like are represented by chemical formulas, unless otherwise specified, the atomic ratios should include all conventionally known atomic ratios and should not necessarily be limited to those within the stoichiometric range.

[0026] In this disclosure, if one or more numerical values ​​are listed as the lower and upper limits of a numerical range, any combination of any one numerical value listed as the lower limit and any one numerical value listed as the upper limit shall also be disclosed.

[0027] In this disclosure, “equipment,” “includes,” “possesses,” and variations thereof are open-ended terms. Open-ended terms may or may not include additional elements in addition to the essential elements. The statement “consists of” is a closed term. However, even a configuration expressed in closed terms may include additional elements that are usually incidental or irrelevant to the subject technology.

[0028] [Embodiment 1: Cutting Tool (1)] A cutting tool according to one embodiment of the present disclosure will be described with reference to Figures 1 to 4. The cutting tool 10 according to one embodiment of the present disclosure (hereinafter also referred to as "Embodiment 1") comprises a base material 11 and a coating 14 disposed on the base material 11. The coating 14 is Ti １－ａ－ｂ Al ａ Sc ｂ It includes a first layer 12 made of N. a is between 0.35 and 0.65. b is between 0.01 and 0.10.

[0029] According to this disclosure, it is possible to provide cutting tools that have a long tool life even when machining difficult-to-cut materials such as nickel-based alloys. The reason for this is presumed to be as follows.

[0030] Among difficult-to-machine materials, nickel-based alloys have high specific strength, which means that when machining them with cutting tools, the cutting tool's edge temperature tends to rise. Therefore, from the perspective of improving the tool life of the cutting tool, it is important that the coating has excellent strength and heat resistance.

[0031] The first layer contains Al, and when a is 0.35 or higher, the hardness and heat resistance of the first layer are improved. When a is 0.65 or lower, the decrease in hardness due to the formation of hexagonal crystals in the first layer can be suppressed.

[0032] Because the first layer contains Sc, the Sc is oxidized during machining. ２ O ３ A passivation is generated consisting of Sc. ２ O ３ Because its melting point is very high at 2485°C, Sc can be used even when machining difficult-to-cut materials such as nickel-based alloys. ２ O ３ The passivation composed of these elements can exist stably. Therefore, the stability of the cutting tool's performance is improved.

[0033] Sc ２ O ３ Because it precipitates at the grain boundaries of TiAlScN, creating a so-called "wedge effect," it can prevent oxygen from diffusing from the surface of the coating through the grain boundaries into the interior of the coating. The wedge effect significantly improves the oxidation resistance of the coating. Furthermore, the wedge effect can suppress the reactivity between the workpiece and the coating, thereby reducing the coefficient of friction between the workpiece and the coating.

[0034] The lattice constant of ScN is 4.51 Å, which is larger than that of TiN (4.23 Å) and AlN (4.12 Å). Therefore, strain is introduced into the first layer, and the microstructure of the first layer is refined. As a result, the first layer becomes harder and its wear resistance is improved.

[0035] In the first layer, if b is 0.01 or greater, Sc ２ O ３ This ensures sufficient formation of the coating, improving the stability of the cutting tool's performance, the oxidation resistance and reactivity resistance of the coating, and the wear resistance of the first layer. When b is 0.10 or less, the reduction in toughness is suppressed, improving chipping resistance.

[0036] The first layer contains Ti, and the amount of Ti is 1-a-b (0.35 ≤ a ≤ 0.65, 0.01 ≤ b ≤ 0.10), which improves the high-temperature strength of the first layer.

[0037] The nickel-based alloy used as the workpiece material mainly consists of Ni, Co, and Fe, with other alloying elements such as Cr added. If Cr is contained in the coating, the components of the coating and the workpiece material will mutually diffuse during cutting, accelerating wear. Therefore, it is preferable for the coating not to contain Cr. In the cutting tool of Embodiment 1, the first layer does not contain Cr, so wear due to mutual diffusion between the coating and the components of the workpiece material is suppressed.

[0038] <Cutting Tools> The cutting tools of Embodiment 1 may be, for example, drills, end mills, replaceable cutting tips for drills, replaceable cutting tips for end mills, replaceable cutting tips for milling, replaceable cutting tips for turning, metal saws, gear cutting tools, reamers, taps, etc.

[0039] Figure 1 is a schematic diagram of an example of a cutting tool. The cutting tool 10 is an end mill and has a cutting edge ridge 3.

[0040] <Base Material> Any composition of base material 2 that is conventionally known can be used. For example, cemented carbide (WC-based cemented carbide, cemented carbide containing WC and Co, cemented carbide with added carbonitrides such as Ti, Ta, and Nb, etc.), cermet (mainly composed of TiC, TiN, TiCN, etc.), high-speed steel, ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, etc.), cubic boron nitride sintered body, or diamond sintered body can be used.

[0041] The base material composition may be WC-based cemented carbide or cermet (especially TiCN-based cermet) from the viewpoint of having an excellent balance between hardness and strength at high temperatures. A base material made of WC-based cemented carbide or cermet can contribute to extending the lifespan of cutting tools.

[0042] <Coating> In the cutting tool of Embodiment 1, the coating can cover at least the portion of the substrate that is involved in cutting. The portion of the substrate that is involved in cutting means, for example, an area on the surface of the substrate that is within 50 μm of the cutting edge. The coating may cover the entire surface of the substrate, or it may cover the entire surface of the portion of the substrate that is involved in cutting. As long as the effects of the cutting tool of this disclosure are not impaired, the absence of a coating on a portion of the portion of the substrate that is involved in cutting does not deviate from the scope of Embodiment 1. As long as the effects of the cutting tool of this disclosure are not impaired, partial differences in the composition of the coating do not deviate from the scope of Embodiment 1.

[0043] The coating is Ti １－ａ－ｂ Al ａ Sc ｂ It includes a first layer made of N. As shown in Figure 2, the first layer 12 may be provided directly on top of the base material 11.

[0044] The coating 14 may include other layers in addition to the first layer 12. As shown in Figures 3 and 4, the coating 14 may include a third layer 13 provided on the side of the first layer 12 opposite to the substrate 11. As shown in Figure 4, the coating 14 may include a second layer 15 positioned between the substrate 11 and the first layer 12.

[0045] The thickness of the coating may be 0.3 μm to 15 μm, 0.5 μm to 12 μm, 1.0 μm to 10 μm, or 2.0 μm to 9.0 μm. When the thickness of the coating is less than 0.3 μm, wear resistance tends to decrease. When the thickness of the coating exceeds 15 μm, the coating tends to chip easily in the initial stages of cutting, which tends to shorten the life of the cutting tool.

[0046] The thickness of the coating is measured by observing the cross-section of the coating using a scanning electron microscope (SEM). Specifically, the observation magnification of the cross-sectional sample is set to 5000 to 10000 times, and the observation area is 100 to 500 μm². ２ For this purpose, the thickness width is measured at three points within a single field of view, and the average value is defined as the "thickness." The thickness of each layer described later is measured in the same manner unless otherwise specified.

[0047] <Composition of the first layer> In the cutting tool of Embodiment 1, the first layer is Ti １－ａ－ｂ Al ａ Sc ｂ It consists of N, where a is between 0.35 and 0.65, and b is between 0.01 and 0.10.

[0048] The above value a is 0.35 or more and 0.65 or less, and may also be 0.45 or more and 0.62 or less, or 0.50 or more and 0.60 or less.

[0049] The above value b is 0.01 or more and 0.10 or less, and may also be 0.02 or more and 0.09 or less, 0.03 or more and 0.07 or less, or 0.03 or more and 0.05 or less.

[0050] The values ​​in 1-a-b above may be 0.25 or more and 0.64 or less, 0.31 or more and 0.52 or less, or 0.35 or more and 0.47 or less.

[0051] The above values ​​a and b are measured by performing elemental analysis on the cross-section of the coating using an energy-dispersive X-ray spectrometer (EDX) attached to a transmission electron microscope (TEM). Specifically, a and b are determined by measuring the energy and number of characteristic X-rays generated when an electron beam is irradiated onto a thinned sample using TEM-EDX, and then performing elemental analysis. The Ti described in Embodiment 2 １－ｃ－ｄ－ｅ Al ｃ Sc ｄ M ｅ c, d, and e in N are also measured using the same method. It has been confirmed that there is no variation in the measurement results, even if the measurement location is arbitrarily selected, as long as the same cutting tool is used for measurement.

[0052] The first layer contains Ti to the extent that it does not impair the effects achieved by the cutting tool of Embodiment 1. １－ａ－ｂ Al ａ Sc ｂ In addition to N, the first layer may also contain unavoidable impurities. Examples of unavoidable impurities include oxygen and carbon. The total content of unavoidable impurities in the first layer may be between 0 atomic percent and 1 atomic percent. The content of unavoidable impurities is measured by the same method as the measurement methods a and b described above. Similarly, the second layer, third layer, A layer, B layer, and C layer, which will be described later, may also contain unavoidable impurities to the extent that they do not impair the effects of the cutting tool of this disclosure.

[0053] In this disclosure, the composition of the first layer Ti １－ａ－ｂ Al ａ Sc ｂ In N, the total number of atoms of Ti, Al, and Sc is A. Ｍ１ Number of atoms A in N Ｎ１ Ratio A Ｎ１ / A Ｍ１ The ratio is between 0.8 and 1.2. Ｎ１ / A Ｍ１ This can be measured by the Rutherford backscattering (RBS) method. The above ratio A Ｎ１ / A Ｍ１ It has been confirmed that the effects of this disclosure will not be impaired if the scope is as described above.

[0054] <Thickness of the first layer> The thickness of the first layer may be 0.3 μm or more and 15.0 μm or less. When the thickness of the first layer is 0.3 μm or more, the stability of the cutting tool performance, the oxidation resistance and reactivity resistance of the coating, and the wear resistance of the first layer are improved. When the thickness of the first layer is 15.0 μm or less, the occurrence of chipping of the coating in the initial stages of cutting is suppressed. The thickness of the first layer may be 0.5 μm or more and 12.0 μm or less, 1.0 μm or more and 10.0 μm or less, 1.0 μm or more and 6.0 μm or less, or 2.0 μm or more and 4.0 μm or less.

[0055] <Second Layer> In the cutting tool of Embodiment 1, the coating may further include a second layer disposed between the substrate and the first layer. The second layer may be placed directly on top of the substrate.

[0056] The second layer may consist of a compound comprising titanium and at least one element selected from the group consisting of carbon, nitrogen, and oxygen. The second layer may consist of TiC, TiCN, TiCNO, or TiN.

[0057] The thickness of the second layer may be between 10 nm and 100 nm. When the thickness of the second layer is between 10 nm and 100 nm, the effect of improving the adhesion between the substrate and the first layer is good. The thickness of the second layer may also be between 15 nm and 80 nm, or between 20 nm and 70 nm.

[0058] <Third Layer> In the cutting tool of Embodiment 1, the coating may further include a third layer provided on the side opposite to the substrate of the first layer. The third layer may be located on the outermost surface of the coating. The third layer may be made of TiCN or TiAlScCN.

[0059] When the third layer consists of TiCN, it is possible to impart a predetermined color by adjusting the composition ratio of N and C. This allows for the addition of aesthetic appeal and distinctiveness to the appearance of cutting tools, making them commercially useful.

[0060] When the third layer consists of TiAlScCN, the atomic ratio of Ti, Al, and Sc in the third layer may be the same as the atomic ratio of Ti, Al, and Sc in the first layer. Specifically, if the atomic ratio of Ti, Al, and Sc in the first layer is Ti:Al:Sc = 1-a-b:a:b, then the atomic ratio of Ti, Al, and Sc in the third layer may also be Ti:Al:Sc = 1-a-b:a:b. This is advantageous in terms of cost because, when the coating is manufactured by the PVD method, the first and third layers can be manufactured using the same target.

[0061] The thickness of the third layer may be between 0.1 μm and 1.0 μm. When the thickness of the third layer is 0.1 μm or more, the effect of improving the sliding properties of the coating is good. When the thickness of the third layer is greater than 1.0 μm, there is a tendency that the effect of further improving the sliding properties of the coating cannot be obtained. Therefore, considering the cost, the thickness of the third layer may be 1.0 μm or less. The thickness of the third layer may also be between 0.2 μm and 0.8 μm, or between 0.3 μm and 0.7 μm.

[0062] [Embodiment 2: Cutting Tool (2)] A cutting tool according to another embodiment of the present disclosure will be described with reference to Figure 5. The cutting tool 10 according to another embodiment of the present disclosure (hereinafter also referred to as "Embodiment 2") comprises a base material 11 and a coating 14 disposed on the base material 11. The coating 14 is Ti １－ｃ－ｄ－ｅ Al ｃ Sc ｄ M ｅ It includes layer A 12A made of N. M is boron and / or silicon. c is 0.35 or more and 0.65 or less. d is 0.01 or more and 0.10 or less. e is 0.01 or more and 0.05 or less.

[0063] According to this disclosure, it is possible to provide cutting tools that have a long tool life even when machining difficult-to-cut materials such as nickel-based alloys. The reason for this is presumed to be as follows.

[0064] Among difficult-to-machine materials, nickel-based alloys have high specific strength, which means that when machining with cutting tools, the cutting tool's edge temperature tends to rise. Therefore, from the perspective of improving the tool life of cutting tools, it is important that the uncoated material has excellent strength and heat resistance.

[0065] The hardness and heat resistance of layer A are improved by containing Al and having a c value of 0.35 or higher. By having a c value of 0.65 or lower, the decrease in hardness due to the formation of hexagonal crystals in layer A can be suppressed.

[0066] As the A layer contains Sc, the following effects can be obtained as described in Embodiment 1. During cutting, Sc is oxidized and Sc ２ O ３ A passivation is generated consisting of Sc. ２ O ３ The generation of improves the stability of the cutting tool's performance. Sc ２ O ３ The wedge effect significantly improves the oxidation resistance of the coating. Sc ２ O ３The wedge effect suppresses the reactivity between the workpiece and the coating, thereby reducing the coefficient of friction with the workpiece. The inclusion of Sc in layer A introduces strain into layer A, resulting in a finer structure of layer A. This increases the hardness of layer A and improves its wear resistance.

[0067] In layer A, if d is 0.01 or greater, Sc ２ O ３ This is sufficiently formed, improving the stability of the cutting tool's performance, the oxidation resistance and reactivity resistance of the coating, and the wear resistance of layer A. Having d 0.10 or less suppresses the decrease in toughness and improves chipping resistance.

[0068] Layer A contains either or both boron (B) and silicon (Si). This makes it easier for the structure of layer A to densify and improve the film strength of layer A.

[0069] In layer A, a value of e greater than 0.01 provides an excellent improvement in film strength. If e is greater than 0.05, excessive lattice strain is introduced into layer A, increasing film stress and making film fracture more likely. If e is 0.05 or less, film fracture is suppressed.

[0070] The high-temperature strength of layer A is improved because layer A contains Ti, and the amount of Ti is 1-c-d-e (0.35 ≤ c ≤ 0.65, 0.01 ≤ d ≤ 0.10, 0.01 ≤ e ≤ 0.05).

[0071] In the cutting tool of Embodiment 2, since layer A does not contain Cr, wear due to interdiffusion between the coating and components in the workpiece made of nickel-based alloy is suppressed.

[0072] The coating 14 may further include a B layer 15B disposed between the substrate 11 and the A layer 12A. The coating 14 may further include a C layer 13C provided on the side of the A layer 12A opposite to the substrate 11. The coating may also include an intermediate layer disposed between the A layer and the B layer, or between the A layer and the C layer.

[0073] The cutting tool of Embodiment 2 is identical in configuration to that of Embodiment 1, except that the coating includes layer A instead of the first layer, layer B instead of the second layer, and layer C instead of the third layer. Note that layer B has the same configuration as the second layer of Embodiment 1. Layers A and C will be described below.

[0074] <Composition of Layer A> In the cutting tool of Embodiment 2, Layer A is Ti １－ｃ－ｄ－ｅ Al ｃ Sc ｄ M ｅ It consists of N, M is either boron or silicon, c is between 0.35 and 0.65, d is between 0.01 and 0.10, and e is between 0.01 and 0.05.

[0075] The above M may be boron or silicon.

[0076] The above value c is between 0.35 and 0.65, and may also be between 0.45 and 0.62, or between 0.50 and 0.60.

[0077] The above value d is 0.01 or more and 0.10 or less, and may also be 0.02 or more and 0.09 or less, 0.03 or more and 0.07 or less, or 0.03 or more and 0.05 or less.

[0078] The above value e is 0.01 or more and 0.05 or less, or it may be 0.02 or more and 0.04 or less.

[0079] The values ​​1-c-d-e above may be 0.20 or more and 0.63 or less, 0.25 or more and 0.51 or less, or 0.28 or more and 0.46 or less.

[0080] In this disclosure, the composition Ti of layer A １－ｃ－ｄ－ｅ Al ｃ Sc ｄ M ｅ In N, the total number of atoms A consists of Ti, Al, Sc, and M. Ｍ２ Number of atoms A in N Ｎ２ Ratio A Ｎ２ / A Ｍ２ The ratio is between 0.8 and 1.2. Ｎ２ / A Ｍ２This can be measured by the Rutherford backscattering (RBS) method. The above ratio A Ｎ２ / A Ｍ２ It has been confirmed that the effects of this disclosure will not be impaired if the scope is as described above.

[0081] <Thickness of Layer A> The thickness of Layer A may be 0.3 μm or more and 15.0 μm or less. When the thickness of Layer A is 0.3 μm or more, the stability of the cutting tool performance, the oxidation resistance and reactivity resistance of the coating, and the wear resistance of Layer A are improved. When the thickness of Layer A is 15.0 μm or less, the occurrence of chipping of the coating in the initial stages of cutting is suppressed. The thickness of Layer A may be 0.5 μm or more and 12.0 μm or less, 1.0 μm or more and 10.0 μm or less, 1.0 μm or more and 6.0 μm or less, or 2.0 μm or more and 4.0 μm or less.

[0082] <C layer> In the cutting tool of Embodiment 2, the coating may further include a C layer provided on the side opposite to the substrate of the A layer. The C layer may be located on the outermost surface of the coating. The C layer may be made of TiCN or TiAlScMCN.

[0083] When the carbon (C) layer consists of TiCN, it is possible to impart a predetermined color by adjusting the composition ratio of N and C. This allows for the addition of aesthetic appeal and distinctiveness to the appearance of cutting tools, making them commercially useful.

[0084] When the C layer is made of TiAlScMCN, the atomic ratio of Ti, Al, Sc, and M in the C layer may be the same as the atomic ratio of Ti, Al, Sc, and M in the A layer. Specifically, if the atomic ratio of Ti, Al, Sc, and M in the A layer is Ti:Al:Sc:M = 1-c-d-e:c:d:e, then the atomic ratio of Ti, Al, Sc, and M in the C layer may also be Ti:Al:Sc:M = 1-c-d-e:c:d:e. According to this, when the coating is manufactured by the PVD method, the A layer and the C layer can be manufactured using the same target, which is advantageous in terms of cost.

[0085] The thickness of the C layer may be between 0.1 μm and 1.0 μm. When the thickness of the C layer is 0.1 μm or more, the effect of improving the sliding properties of the coating is good. When the thickness of the C layer exceeds 1.0 μm, there is a tendency that the effect of further improving the sliding properties of the coating cannot be obtained. Therefore, considering the cost, the thickness of the C layer may be 1.0 μm or less. The thickness of the C layer may also be between 0.2 μm and 0.8 μm, or between 0.3 μm and 0.7 μm.

[0086] [Embodiment 3: Method for Manufacturing a Cutting Tool] Embodiment 3 describes a method for manufacturing a cutting tool according to Embodiment 1 or Embodiment 2. The method for manufacturing a cutting tool according to Embodiment 3 comprises a first step of preparing a substrate and a second step of forming a coating on the substrate. The second step includes a step of forming a first layer or layer A. Details of each step are described below.

[0087] <Step 1> In Step 1, the substrate is prepared. The substrate can be the substrate described in Embodiment 1. Any conventionally known substrate can be prepared.

[0088] <Second Step> In the second step, a coating is formed on the substrate. The second step includes the step of forming the first layer or layer A.

[0089] In the step of forming the first layer or layer A, the first layer or layer A is formed using the Physical Vapor Deposition (PVD) method. To improve the abrasion resistance of the coating including the first layer or layer A, it is preferable to form a layer made of a highly crystalline compound. The inventors investigated various methods for forming the first layer or layer A and found that using the Physical Vapor Deposition method is preferable.

[0090] As the PVD method, at least one selected from the group consisting of cathode arc ion plating, balanced magnetron sputtering, unbalanced magnetron sputtering, and HiPIMS can be used. In particular, it is preferable to use the cathode arc ion plating method, which has a high ionization rate of the raw material elements. When the cathode arc ion plating method is used, it is possible to perform metal ion bombardment treatment on the surface of the substrate before forming the first layer or layer A, so that the adhesion between the substrate and the coating is greatly improved.

[0091] Cathode arc ion plating can be performed, for example, by placing a substrate and a target as a cathode in the apparatus, then applying a high voltage to the target to generate an arc discharge, thereby ionizing and evaporating the atoms constituting the target, and depositing the material onto the substrate.

[0092] Balanced magnetron sputtering can be performed, for example, by placing a substrate in the apparatus and a target on a magnetron electrode equipped with a magnet that forms a balanced magnetic field, applying high-frequency power between the magnetron electrode and the substrate to generate a gas plasma, and then colliding the gas ions generated by this gas plasma with the target to deposit the atoms emitted from the target onto the substrate.

[0093] Unbalanced magnetron sputtering can be performed, for example, by making the magnetic field generated by the magnetron electrode in the balanced magnetron sputtering method described above unbalanced. Furthermore, the HiPIMS method, which allows for the application of higher voltages and yields denser films, can also be used.

[0094] <Other Processes> In addition to the process of forming the first layer or layer A, the second process may include surface treatment processes such as surface grinding and shot blasting. The second process may also include the process of forming other layers (at least one of the second layer, third layer, layer B, layer C, and intermediate layer). These other layers can be formed by conventionally known chemical vapor deposition or physical vapor deposition methods. From the viewpoint of being able to continuously form the first layer or layer A and the other layers within a single physical vapor deposition apparatus, the other layers can be formed by physical vapor deposition.

[0095] This embodiment will be described in more detail by reference to examples. However, this embodiment is not limited by these examples.

[0096] <Preparation of Cutting Tools> <Step 1> For samples 1 to 17 and samples 101 to 105, cemented carbide ball end mills (2 blades, ball radius 5 mm) were prepared. For samples 21 to 39 and samples 121 to 133, cemented carbide ball end mills (2 blades, ball radius 3 mm) were prepared.

[0097] <Step 2> The substrate was set in the designated position in the arc ion plating apparatus (manufactured by Kobe Steel, Ltd., product name: AIP). The target was set in the arc-type evaporation source inside the apparatus.

[0098] When forming a second layer or layer B on the substrate, the second layer or layer B was formed by the following method: While rotating the substrate, at least one of nitrogen, methane, and oxygen was introduced into the apparatus as a reaction gas, and while maintaining the substrate temperature at 500°C, the reaction gas pressure at 1 Pa, and the bias power supply voltage at a constant value in the range of 50V to 800V, an arc current of 150A was supplied to the target to generate metal ions from the target, thereby forming a second layer having the composition shown in Table 1, or a layer B having the compositions shown in Tables 2 and 3, on the substrate. The composition of the target is Ti. When forming the first layer or layer A directly on the substrate, the formation of the second layer or layer B is not performed.

[0099] The first layer was formed directly above the substrate or on top of the second layer. Alternatively, the A layer was formed directly above the substrate or on top of the B layer. With the substrate rotating, nitrogen was introduced as the reaction gas in the apparatus, and while maintaining the substrate temperature at 500°C, the reaction gas pressure at 4 Pa, and the bias power supply voltage at a certain constant value in the range of 50V to 300V, an arc current of 150A was supplied to the target to generate metal ions from the target and form the first layer or the A layer. When forming the first layer, the target composition was adjusted so that the ratios of Ti, Al, and Sc were the same as the ratios of the first layer composition in Table 1. When forming the A layer, the target composition was adjusted so that the ratios of Ti, Al, Sc, B, and Si were the same as the ratios of the A layer composition in Tables 2 and 3. When the thickness of the first layer or the A layer reached the thickness shown in Tables 1, 2, and 3, the current supplied to the evaporation source was stopped.

[0100] When forming the third layer on the first layer, or when forming the C layer on the A layer, the following steps were performed.

[0101] When the third layer, or C layer, is made of TiCN, the third layer, or C layer, is formed by supplying an arc current of 150A to the target while maintaining the temperature of the substrate 2 at 500°C, the reaction gas pressure at 2Pa, and the bias power supply voltage at a constant value in the range of 100V to 500V, while introducing nitrogen and methane gas as reaction gases into the apparatus. The target is composed of Ti. The current supplied to the evaporation source was stopped when the thickness of the third layer, or C layer, reached the thickness shown in Tables 1 to 3.

[0102] When the third layer, or C layer, is made of TiAlScMCN, the third layer, or C layer, is formed by supplying an arc current of 150A to the target while introducing nitrogen and methane gas as reaction gases into the chamber 101, maintaining the temperature of the substrate 2 at 500°C, the reaction gas pressure at 2Pa, and the bias power supply voltage at a certain constant value in the range of 100V to 500V, thereby generating metal ions from the target. The composition of the target used to form the third layer is the same as the composition of the target used to form the first layer. The composition of the target used to form the C layer is the same as the composition of the target used to form the A layer. The current supplied to the evaporation source was stopped when the thickness of the third layer, or C layer, reached the thickness shown in Tables 1 to 3. Cutting tools for each sample were obtained as a result of the above procedure.

[0103]

[0104]

[0105]

[0106] [Evaluation] For each sample of cutting tool, the composition and thickness of the first layer, second layer, third layer, A layer, B layer, and C layer were measured using the methods described in Embodiments 1 and 2. The results are shown in Tables 1 to 3.

[0107] [Cutting Test 1] Side machining of a workpiece made of Inconel 718 was performed using ball end mills of samples 1 to 17 and samples 101 to 105. The machining conditions were: cutting speed Vc 120 mm / min, feed rate per tooth fz 0.05 mm / t, depth of cut (axial) ap 0.6 mm, depth of cut (radial) ae 0.6 mm, and external lubrication. The cutting distance until the wear width or chip width of the cutting edge reached 100 μm was measured. A longer cutting distance indicates a longer tool life. The results are shown in the "Cutting Distance" column of "Cutting Test 1" in Table 1. Note that the above machining conditions are suitable for machining difficult-to-machine materials.

[0108] The cutting tools of Samples 1 to 17 correspond to the examples. The cutting tools of Samples 101 to 105 correspond to the comparative examples. It was confirmed that the cutting tools of Samples 1 to 17 have a longer tool life than the cutting tools of Samples 101 to 105.

[0109] [Cutting Test 2] Side machining of a workpiece made of Inconel 718 was performed using ball end mills of samples 21 to 39 and samples 121 to 133. The machining conditions were: cutting speed Vc 80 mm / min, feed rate per tooth fz 0.04 mm / t, depth of cut (axial) ap 0.3 mm, depth of cut (radial) ae 0.3 mm, and external lubrication. The cutting distance until the wear width or chip width of the cutting edge reached 100 μm was measured. A longer cutting distance indicates a longer tool life. The results are shown in the "Cutting Distance" column of "Cutting Test 2" in Tables 2 and 3. Note that the above machining conditions are suitable for machining difficult-to-machine materials.

[0110] The cutting tools of samples 21 to 39 correspond to the examples. The cutting tools of samples 121 to 133 correspond to the comparative examples. It was confirmed that the cutting tools of samples 21 to 39 have a longer tool life than the cutting tools of samples 121 to 133.

[0111] While embodiments and examples of this disclosure have been described above, it is intended from the outset that the configurations of each of the embodiments and examples described above may be combined or modified in various ways as appropriate. The embodiments and examples disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than the embodiments and examples described above, and all modifications within the scope of the claims are intended to be included in the meaning of equivalences.

[0112] 3 Blade edge ridgeline, 10 Cutting tool, 11 Base material, 12 First layer, 12A A layer, 13 Third layer, 13C C layer, 14 Coating, 15 Second layer, 15B B layer.

Claims

1. A cutting tool comprising a base material and a coating disposed on the base material, wherein the coating is made of Ti １－ａ－ｂ Al ａ Sc ｂ A cutting tool comprising a first layer made of N, wherein a is 0.35 or more and 0.65 or less, and b is 0.01 or more and 0.10 or less.

2. The cutting tool according to claim 1, wherein the thickness of the first layer is 0.3 μm or more and 15.0 μm or less.

3. The cutting tool according to claim 1 or claim 2, wherein the coating further comprises a second layer disposed between the substrate and the first layer, the second layer being a compound of titanium and at least one element selected from the group consisting of carbon, nitrogen, and oxygen, and the thickness of the second layer being 10 nm or more and 100 nm or less.

4. The cutting tool according to any one of claims 1 to 3, wherein the coating further comprises a third layer provided on the side of the first layer opposite to the substrate, the third layer being made of TiCN or TiAlScCN, and the thickness of the third layer being 0.1 μm or more and 1.0 μm or less.

5. A cutting tool comprising a base material and a coating disposed on the base material, wherein the coating is Ti １－ｃ－ｄ－ｅ Al ｃ Sc ｄ M ｅ A cutting tool comprising an A layer made of N, wherein M is boron and silicon, or both, c is 0.35 or more and 0.65 or less, d is 0.01 or more and 0.10 or less, and e is 0.01 or more and 0.05 or less.

6. The cutting tool according to claim 5, wherein the thickness of the A layer is 0.3 μm or more and 15.0 μm or less.

7. The cutting tool according to claim 5 or 6, wherein the coating further comprises a B layer disposed between the substrate and the A layer, the B layer being a compound of titanium and at least one element selected from the group consisting of carbon, nitrogen, and oxygen, and the thickness of the B layer being 10 nm or more and 100 nm or less.

8. The cutting tool according to any one of claims 5 to 7, wherein the coating further comprises a C layer provided on the side of the A layer opposite to the substrate, the C layer being made of TiCN or TiAlScMCN, the M being boron and silicon, and the thickness of the C layer being 0.1 μm or more and 1.0 μm or less.

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