Cutting tool

Abstract

A cutting tool comprising a substrate and a coating film provided on the substrate, wherein the coating film includes a first layer, and the first layer is composed of AlaTibCr(1-a-b-c-d)SicCudN, in which a, b, c, and d satisfy the relationships 0.50 ≤ a ≤ 0.75, 0.10 ≤ b ≤ 0.25, 0.005 ≤ c ≤ 0.20, 0.005 ≤ d ≤ 0.10, and a + b + c + d < 1.

Description

cutting tools

[0001] The present disclosure relates to cutting tools.

[0002] Conventionally, cutting tools including a substrate and a coating disposed on the substrate have been used in cutting processes (Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2003-71611

[0004] The cutting tool of the present disclosure is a cutting tool including a substrate and a coating provided on the substrate, wherein the coating includes a first layer, and the first layer is Al ａ Ti ｂ Cr(1-a-b-c-d)Si ｃ Cu ｄ N, wherein the a, b, c, and d satisfy 0.50≦a≦0.75, 0.10≦b≦0.25, 0.005≦c≦0.20, 0.005≦d<0.10, and a+b+c+d<1.

[0005] FIG. 1 is a schematic enlarged cross-sectional view of an example of a cutting tool according to Embodiment 1. FIG. 2 is a schematic enlarged cross-sectional view of an example of a cutting tool according to Embodiment 1. FIG. 3 is a schematic enlarged cross-sectional view of an example of a cutting tool according to Embodiment 1. FIG. 4 is a schematic enlarged cross-sectional view of an example of a cutting tool according to Embodiment 1. FIG. 5 is a perspective view illustrating one aspect of a cutting tool. FIG. 6 is a schematic cross-sectional view of a cathodic arc ion plating apparatus used in the examples. FIG. 7 is a schematic top view of the cathodic arc ion plating apparatus shown in FIG. 6.

[0006] [Problem to be Solved by the Present Disclosure] In recent years, work materials have become more diverse, and particularly in the fields of aircraft and medicine, cutting of nickel-based alloys, which are known as difficult-to-cut materials, is becoming more common. When nickel-based alloys are continuously cut using cutting tools, the cutting edge temperature becomes high, shortening the life of the cutting tool. Therefore, there is a demand for cutting tools that can have a long tool life, especially when cutting nickel-based alloys continuously.

[0007] Therefore, an object of the present disclosure is to provide a cutting tool that can have a long tool life, particularly when continuously machining nickel-based alloys.

[0008] Effect of the Present Disclosure According to the present disclosure, it is possible to provide a cutting tool that can have a long tool life, particularly in continuous machining of nickel-based alloys.

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described. (1) A cutting tool of the present disclosure is a cutting tool including a substrate and a coating provided on the substrate, wherein the coating includes a first layer, and the first layer is Al ａ Ti ｂ Cr(1-a-b-c-d)Si ｃ Cu ｄ N, wherein the a, b, c, and d satisfy 0.50≦a≦0.75, 0.10≦b≦0.25, 0.005≦c≦0.20, 0.005≦d<0.10, and a+b+c+d<1.

[0010] According to the present disclosure, it is possible to provide a cutting tool that can have a long tool life, particularly in continuous machining of nickel-based alloys.

[0011] (2) In the above (1), the c and d may satisfy the relationship c / d ≥ 1. This further improves the tool life.

[0012] (3) In the above (1) or (2), the thickness of the first layer may be 0.5 μm or more and 10 μm or less, which further improves the tool life.

[0013] (4) In any of the above (1) to (3), the coating may further include a second layer provided between the substrate and the first layer, and the second layer may be made of at least one element selected from a first group consisting of Group 4 elements, Group 5 elements, Group 6 elements, aluminum, and silicon of the periodic table, or a first compound consisting of at least one element selected from the first group and at least one element selected from a second group consisting of carbon, nitrogen, oxygen, and boron.

[0014] This further improves the tool life.

[0015] (5) In any of the above (1) to (4), the coating may further include a third layer provided on the first layer opposite to the substrate, and the third layer may be made of at least one element selected from a first group consisting of Group 4 elements, Group 5 elements, Group 6 elements, aluminum, and silicon of the periodic table, or a second compound consisting of at least one element selected from the first group and at least one element selected from a second group consisting of carbon, nitrogen, oxygen, and boron.

[0016] This further improves the tool life.

[0017] (6) In any one of the above (1) to (5), the thickness of the coating may be 0.5 μm or more and 12 μm or less, thereby further improving the tool life.

[0018] (7) In any of the above (1) to (6), the substrate may be made of cemented carbide, cermet, cubic boron nitride sintered body, diamond sintered body, high-speed steel, or ceramics, which further improves the tool life.

[0019] [Details of the Embodiments of the Present Disclosure] Specific examples of cutting tools according to the present disclosure will be described below with reference to the drawings. In the drawings of the present disclosure, the same reference numerals represent the same or corresponding parts. Furthermore, dimensional relationships such as length, width, thickness, and depth have been appropriately changed for clarity and simplification of the drawings, and do not necessarily represent actual dimensional relationships.

[0020] In the present disclosure, the notation in the form of "A to B" means A or more and B or less, and when no unit is specified for A and a unit is specified only for B, the unit of A and the unit of B are the same.

[0021] In the present disclosure, when a compound or the like is represented by a chemical formula, unless the atomic ratio is particularly limited, it is intended to include any conventionally known atomic ratio, and should not necessarily be limited to only those within the stoichiometric range.

[0022] In the present disclosure, when one or more numerical values ​​are listed as the lower limit and the upper limit of a numerical range, the combination of any one numerical value listed as the lower limit and any one numerical value listed as the upper limit is also considered to be disclosed.

[0023] [Embodiment 1: Cutting Tool] As shown in FIGS. 1 to 4, a cutting tool 1 according to one embodiment of the present disclosure (hereinafter also referred to as "Embodiment 1") is a cutting tool 1 including a substrate 2 and a coating 3 provided on the substrate 2, wherein the coating 3 includes a first layer 13, and the first layer 13 is made of Al ａ Ti ｂ Cr(1-a-b-c-d)Si ｃ Cu ｄ N, and a, b, c, and d satisfy 0.50≦a≦0.75, 0.10≦b≦0.25, 0.005≦c≦0.20, 0.005≦d<0.10, and a+b+c+d<1.

[0024] The cutting tool of the first embodiment has a long tool life, especially in continuous machining of nickel-based alloys. The reason for this is presumably as follows.

[0025] The aluminum (Al) contained in the first layer improves the high-temperature hardness of the first layer. When the value of a is 0.50 or more, the high-temperature hardness and heat resistance of the first layer are improved. When the value of a is 0.75 or less, the generation of hexagonal crystals is suppressed, and a decrease in the high-temperature hardness of the first layer is suppressed.

[0026] Titanium (Ti) contained in the first layer improves the high-temperature strength of the first layer. When the above b is 0.10 or more, the effect of improving the high-temperature strength can be sufficiently obtained. When the above b is 0.25 or less, the aluminum content of the first layer can be sufficiently secured, thereby improving the high-temperature hardness of the first layer.

[0027] The inclusion of chromium (Cr) and aluminum in the first layer improves the heat resistance and high-temperature oxidation resistance of the first layer.

[0028] Silicon (Si) contained in the first layer improves the oxidation resistance and heat resistance of the first layer. When the above c is 0.005 or more, the oxidation resistance of the first layer is improved. In addition, the crystal grains of the first layer are refined, and the hardness of the first layer is improved. When the above c is 0.20 or less, the decrease in toughness of the first layer is suppressed, and the occurrence of chipping is suppressed.

[0029] The copper (Cu) contained in the first layer has low solubility in nickel and chromium (when the nickel-based alloy is a nickel-chromium alloy), which are components of the nickel-based alloy, and therefore the first layer containing copper is less likely to adhere to the workpiece made of the nickel-based alloy during cutting.

[0030] On the other hand, copper does not form nitrides, and therefore tends to disrupt the crystal lattice of the nitride coating, reducing the hardness of the coating. By adding copper and silicon to the first layer, the hardness of the first layer can be improved. This finding was discovered by the inventors after extensive research.

[0031] As described above, the first layer of embodiment 1 can have excellent high-temperature hardness and heat resistance due to aluminum, excellent high-temperature strength due to titanium, excellent oxidation resistance and heat resistance due to chromium and silicon, excellent adhesion resistance due to copper, and high hardness due to the addition of copper and silicon, and can have a long tool life even in continuous machining of nickel-based alloys, which tend to have high cutting edge temperatures during cutting.

[0032] 1 to 4 , a cutting tool 1 according to a first embodiment includes a substrate 2 and a coating 3 provided on the substrate 2. The coating 3 may cover the entire surface of the substrate 2. It is also within the scope of this embodiment if a portion of the substrate 2 is not covered by the coating 3 or if the coating 3 has a partially different configuration. The coating 3 may cover at least a portion of the substrate 2 that is involved in cutting. In the present disclosure, the portion of the substrate 2 that is involved in cutting refers to a region of the substrate 2 that is surrounded by a cutting edge ridge and an imaginary surface that is, depending on the size and shape of the substrate 2, a distance from the cutting edge ridge toward the substrate 2 along a perpendicular to a tangent to the cutting edge ridge, of, for example, 5 mm, 3 mm, 2 mm, 1 mm, or 0.5 mm.

[0033] The cutting tool 1 of this embodiment can be suitably used as cutting tools 1 such as drills, end mills, indexable cutting tips for drills, indexable cutting tips for end mills, indexable cutting tips for milling, indexable cutting tips for turning, metal saws, gear cutting tools, reamers, and taps.

[0034] 5 is a perspective view illustrating one embodiment of a cutting tool. The cutting tool 1 is used as an indexable cutting insert. The cutting tool 1 has a rake face 21, a flank 22, and a cutting edge ridge 23 where the rake face 21 and the flank 22 intersect.

[0035] <Substrate> Any conventionally known material can be used as the substrate.For example, the substrate can be made of cemented carbide (WC-based cemented carbide, cemented carbide containing WC and Co, cemented carbide made by adding carbonitrides of Ti, Ta, Nb, etc. to WC and Co, 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.

[0036] The substrate may be, in particular, a WC-based cemented carbide or cermet (particularly a TiCN-based cermet). WC-based cemented carbide or cermet has an excellent balance between hardness and strength, particularly at high temperatures, and therefore, when used as a substrate for a cutting tool, can contribute to extending the life of the cutting tool.

[0037] <Coating> <Coating Configuration> The coating of embodiment 1 includes a first layer. By covering the substrate, the coating improves various properties of the cutting tool, such as wear resistance and chipping resistance, and has the effect of extending the life of the cutting tool. The coating may include other layers in addition to the first layer. As shown in FIGS. 2 to 4 , these other layers include a second layer 14 provided between the substrate 2 and the first layer 13, and a third layer 16 provided on the side of the first layer 13 opposite the substrate 2.

[0038] <Coating Thickness> The coating thickness may be 0.4 μm or more and 20 μm or less, 0.5 μm or more and 12 μm or less, 1 μm or more and 10 μm or less, or 2 μm or more and 8 μm or less. When the coating thickness is 0.5 μm or more, the life of the cutting tool can be extended. On the other hand, when the total thickness of the coating is 12 μm or less, chipping of the coating is less likely to occur in the early stages of cutting, and the life of the cutting tool can be extended.

[0039] The thickness of the coating is measured by observing the cross section of the coating using a scanning electron microscope (SEM). The specific measurement method is as follows: The cutting tool is cut in a direction along the normal to the main surface of the coating to prepare a cross section sample. The cross section sample is observed with the SEM. The observation magnification is 5000 to 10000 times, and the measurement field of view is 100 to 500 μm. ２ The thickness width of the coating is measured at three points in one field of view, and the average value of the thickness widths at the three points is calculated. This average value corresponds to the thickness of the coating. The thickness of each layer described below is also measured in the same manner unless otherwise specified.

[0040] <Crystalline structure of coating> The crystalline structure of the coating may be cubic. When the crystalline structure of the coating is cubic, the hardness of the coating is improved. The crystalline structure of each layer in the coating (first layer, third layer, second layer, etc.) may also be cubic. The crystalline structure of the coating and each layer in the coating can be analyzed using an X-ray diffraction device known in the art.

[0041] <<Hardness of Coating>> The hardness of the coating may be 30 GPa or more and 50 GPa or less, or 35 GPa or more and 45 GPa or less. According to this, the coating has sufficient hardness. The hardness of the coating is measured by a nanoindenter method (measuring device: ENT-1100a manufactured by Elionix). Specifically, the method is performed in accordance with ISO 14577, with a measuring load of 10 mN (1 gf), and the hardness is measured at 10 points on the surface of the coating, and the average value of the hardness values ​​at the 10 points is calculated. This average value corresponds to the hardness of the coating.

[0042] <First layer> <Composition of first layer> The first layer is Al ａ Ti ｂ Cr(1-a-b-c-d)Siｃ Cu ｄ N, and a, b, c, and d satisfy 0.50≦a≦0.75, 0.10≦b≦0.25, 0.005≦c≦0.20, 0.005≦d<0.10, and a+b+c+d<1.

[0043] a may be 0.500 or more and 0.750 or less, 0.550 or more and 0.700 or less, or 0.600 or more and 0.650 or less.

[0044] b may be 0.100 or more and 0.250 or less, 0.100 or more and 0.200 or less, or 0.120 or more and 0.180 or less.

[0045] c may be 0.005 or more and 0.200 or less, 0.010 or more and 0.150 or less, or 0.050 or more and 0.100 or less.

[0046] d may be 0.005 or more and 0.100 or less, 0.010 or more and 0.090 or less, or 0.030 or more and 0.080 or less.

[0047] a+b+c+d is less than 1, and may be 0.950 or less, 0.910 or less, or 0.890 or less.

[0048] c / d may be 1 or more, may exceed 1, may be 1 or more and 20 or less, may be 1.2 or more and 10 or less, may be 1.25 or more and 5 or less, or may be 2 or more and 4 or less. When c / d is 1 or more, the film hardness is improved and the tool life is improved.

[0049] In the present disclosure, "the first layer is Al ａ Ti ｂ Cr(1-a-b-c-d)Si ｃ Cu ｄ "Consists of AlN" means that the first layer is made of AlN as long as it does not impair the effect of the present disclosure. ａ Ti ｂ Cr(1-a-b-c-d)Si ｃ Cu ｄThis means that the first layer may contain inevitable impurities in addition to N. Examples of inevitable impurities include oxygen and carbon. The total content of inevitable impurities in the first layer may be greater than 0 atomic % and less than 1 atomic %. In the present disclosure, "atomic %" refers to the ratio (%) of the number of atoms to the total number of atoms constituting the layer.

[0050] The contents of a, b, c, d, and inevitable impurities in the first layer are measured by elemental analysis of a cross section of the coating using a transmission electron microscope (TEM). The specific measurement method is as follows: A cutting tool is cut in a direction normal to the main surface of the coating to prepare a thin section sample containing a cross section of the coating. An EDS (Energy Dispersive X-ray Spectroscopy) attached to the TEM is used to irradiate the thin section sample with an electron beam, and the energy and number of characteristic X-rays generated are measured to perform elemental analysis of the first layer. Five non-overlapping measurement areas are arbitrarily set in the first layer, and elemental analysis is performed at the five locations. The average composition of the five locations is determined. This average composition corresponds to the composition of the first layer. The compositions of the second and third layers, described below, are also measured using a similar method. It has been confirmed that there is no variation in the measurement results even when measurement locations are arbitrarily selected.

[0051] In the present disclosure, the composition of the first layer is Al ａ Ti ｂ Cr(1-a-b-c-d)Si ｃ Cu ｄ In N, the total number of Al, Ti, Cr, Si and Cu atoms A Ｍ１ Number of N atoms A Ｎ１ Ratio A Ｎ１ / A Ｍ１ is 0.8 or more and 1.2 or less. Ｎ１ / A Ｍ１ can be measured by Rutherford backscattering (RBS) method. Ｎ１ / A Ｍ１ It has been confirmed that the effects of the present disclosure are not impaired if the value is within the above range.

[0052] <Thickness of First Layer> The thickness of the first layer may be 0.4 μm or more and 12 μm or less, 0.5 μm or more and 10 μm or less, 1 μm or more and 8 μm or less, or 2 μm or more and 5 μm or less. When the thickness of the first layer is 0.5 μm or more, the wear resistance is excellent and the life of the cutting tool can be extended. On the other hand, when the thickness of the first layer is 10 μm or less, chipping of the coating is unlikely to occur in the early stage of cutting, and the life of the cutting tool can be extended.

[0053] 2 and 4, the coating 3 can further include a second layer 14 provided between the substrate 2 and the first layer 13. The second layer 14 may be provided directly on the substrate.

[0054] The second layer may be composed of at least one element selected from Group 1 consisting of Group 4, Group 5, and Group 6 elements, aluminum (Al), and silicon (Si), or a first compound consisting of at least one element selected from Group 1 and at least one element selected from Group 2 consisting of carbon (C), nitrogen (N), oxygen (O), and boron (B). Examples of Group 4 elements include titanium (Ti), zirconium (Zr), and hafnium (Hf). Examples of Group 5 elements include vanadium (V), niobium (Nb), and tantalum (Ta). Examples of Group 6 elements include chromium (Cr), molybdenum (Mo), and tungsten (W). The second layer can improve adhesion between the substrate and the coating, thereby improving tool life. The second layer may contain unavoidable impurities in addition to at least one element selected from Group 1 or the first compound, as long as the effects of the present disclosure are not impaired.

[0055] The second layer may be made of a first compound consisting of at least one element selected from Group 1A consisting of Cr, Al, Ti, and Si, or at least one element selected from Group 1A and at least one element selected from Group 2 consisting of carbon, nitrogen, oxygen, and boron.

[0056] Examples of the first compound include TiWCN, TiN, TiAlN, TiAlON, and Al ２ O３ , TiAlSiN, TiCrSiN, TiAlCrSiN, AlCrN, AlCrO, AlCrON, AlCrSiN, AlCrBN, TiZrN, TiAlMoN, TiAlNbN, TiSiN, AlCrTaN, AlVN, AlTiVN, TiB ２ , TiCrHfN, CrSiWN, TiAlCN, TiSiCN, AlZrON, AlCrCN, AlHfN, CrSiBON, TiAlWN, AlCrMoCN, TiCN, TiCON, ZrN and ZrCN.

[0057] The thickness of the second layer is not particularly limited as long as it does not impair the effects of this embodiment, but can be, for example, 0.1 μm or more and 2 μm or less.

[0058] 3 and 4, the coating 3 may further include a third layer 16 provided on the side of the first layer 13 opposite the substrate 2. The third layer 16 may be provided directly on the first layer 13. Another layer may be provided between the first layer 13 and the third layer 16. The third layer 16 may be the outermost layer.

[0059] The third layer may be composed of at least one element selected from Group 1 consisting of Group 4, Group 5, and Group 6 elements of the periodic table, aluminum (Al), and silicon (Si), or a second compound consisting of at least one element selected from Group 1 and at least one element selected from Group 2 consisting of carbon (C), nitrogen (N), oxygen (O), and boron (B). The third layer can reduce the friction coefficient of the coating and extend the life of the cutting tool. The third layer may contain impurities in addition to at least one element selected from Group 1 or the second compound, as long as the effects of the present disclosure are not impaired.

[0060] The third layer may be made of at least one element selected from Group 1A consisting of Cr, Al, Ti, and Si, or a second compound made of at least one element selected from Group 1A and at least one element selected from Group 2 consisting of carbon, nitrogen, oxygen, and boron.

[0061] Examples of the second compound include AlTiBN, TiAlN, TiAlON, and Al ２ O ３ , TiAlSiN, TiCrSiN, TiAlCrSiN, AlCrN, AlCrO, AlCrON, AlCrSiN, AlCrBN, TiZrN, TiAlMoN, TiAlNbN, TiSiN, AlCrTaN, AlVN, AlTiVN, TiB ２ , TiCrHfN, CrSiWN, TiAlCN, TiSiCN, AlZrON, AlCrCN, AlHfN, CrSiBON, TiAlWN, AlCrMoCN, TiCN, TiCON, ZrN and ZrCN.

[0062] The thickness of the third layer may be 0.1 μm or more and 2 μm or less. When the thickness of the third layer is 0.1 μm or more, the lubricity-imparting effect of the third layer is easily obtained. There is no particular upper limit to the thickness of the third layer, but when it exceeds 2 μm, the above-mentioned lubricity-imparting effect tends not to be further improved. Therefore, in consideration of cost, the thickness of the third layer may be 2 μm or less.

[0063] <Intermediate Layer> The coating may include an intermediate layer provided between the third layer and the first layer, or between the first layer and the second layer. Examples of intermediate layers include TiAlCeN, AlTiN, AlTiBN, AlTiSiN, AlTiYN, and AlTiLaN. The thickness of the intermediate layer may be 0.1 μm or more and 2 μm or less, 0.3 μm or more and 1.5 μm or less, or 0.4 μm or more and 1.0 μm or less.

[0064] [Embodiment 2: Method for Manufacturing Cutting Tool] In embodiment 2, a method for manufacturing the cutting tool of embodiment 1 will be described. The manufacturing method includes 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. Details of each step will be described below.

[0065] <First Step> In the first step, a substrate is prepared. The substrate may be the substrate described in embodiment 1. Any substrate that is conventionally known may be prepared.

[0066] <Second Step> In the second step, a coating is formed on the substrate. The second step includes a step of forming a first layer.

[0067] In the step of forming the first layer, the first layer is formed using a physical vapor deposition (PVD) method. Forming a layer made of a highly crystalline compound is highly effective in improving the abrasion resistance of a coating including the first layer. The inventors have investigated various methods for forming the first layer and found that using a physical vapor deposition method is highly effective.

[0068] The PVD method may be at least one selected from the group consisting of cathodic arc ion plating, balanced magnetron sputtering, unbalanced magnetron sputtering, and HiPIMS. In particular, cathodic arc ion plating, which has a high ionization rate of the raw material elements, may be used. When cathodic arc ion plating is used, it is possible to perform ion bombardment of metal on the surface of the substrate before forming the first layer, thereby significantly improving adhesion between the substrate and the coating including the first layer.

[0069] The cathodic arc ion plating method can be carried out, for example, by placing a substrate in an apparatus and a target as a cathode, and then applying a high voltage to the target to generate an arc discharge, thereby ionizing and evaporating the atoms that make up the target, and depositing the material on the substrate.

[0070] <Other Steps> In addition to the step of forming the first layer, the second step may include a surface treatment step such as surface grinding or shot blasting. The second step may also include the step of forming other layers such as a second layer, a third layer, and an intermediate layer. The other layers may be formed by a conventionally known chemical vapor deposition method or physical vapor deposition method. From the viewpoint that the other layers can be formed continuously with the first layer in a single physical vapor deposition apparatus, the other layers may be formed by physical vapor deposition.

[0071] The present embodiment will be described in more detail with reference to examples, although the present embodiment is not limited to these examples.

[0072] <<Fabrication of Cutting Tool>> FIG. 6 is a schematic cross-sectional view of the cathodic arc ion plating apparatus used in this example, and FIG. 7 is a schematic top view of the apparatus of FIG.

[0073] 6 and 7, cathodes 106 and 107 for the first layer, which are alloy targets serving as the metal raw material for the coating 3, and a rotary substrate holder 104 for placing the substrate are installed in a chamber 101. The compositions of the cathodes 106 and 107 are adjusted to obtain the compositions shown in Table 1 below.

[0074] In the sample device in which the second or third layer is formed, a cathode for the second layer or a cathode for the third layer (not shown) is also installed in the chamber 101. The compositions of the cathode for the second layer and the cathode for the third layer are adjusted so as to obtain the compositions shown in Table 2 below.

[0075] An arc power supply 108 is attached to cathode 106, and an arc power supply 109 is attached to cathode 107. A bias power supply 110 is attached to substrate holder 104. A gas inlet for introducing gas 105 and a gas outlet 103 for adjusting the pressure inside chamber 101 are provided inside chamber 101, and the gas inside chamber 101 can be sucked out from gas outlet 103 by a vacuum pump.

[0076] A substrate made of cemented carbide having a grade of JIS K20 and a tip having a shape of JIS CNMG120416 was attached to the substrate holder 104 .

[0077] Next, the pressure inside the chamber 101 is reduced by a vacuum pump, and the substrate is heated to 500° C. by a heater installed inside the apparatus while being rotated, until the pressure inside the chamber 101 reaches 1.0×10 －４The chamber was evacuated to a vacuum of 2.0 Pa. Next, argon gas was introduced through the gas inlet to maintain the pressure inside the chamber 101 at 2.0 Pa, and the voltage of the bias power supply 110 was gradually increased to -1000 V, and the surface of the substrate was cleaned for 15 minutes. Thereafter, the argon gas was exhausted from the chamber 101 to clean the substrate (argon bombardment treatment). In this manner, the substrate for each sample cutting tool was prepared.

[0078] Next, with the substrate rotated at the center, nitrogen was introduced as a reactive gas, and an arc current of 150 A was supplied to each of cathodes 106 and 107 while maintaining the substrate temperature at 550°C, the reactive gas pressure at 2.0 Pa, and the voltage of bias power supply 110 at a constant value in the range of -50 V to -300 V. Metal ions were generated from cathodes 106 and 107, and a first layer having the composition shown in Table 1 below was formed on the substrate.

[0079] When a second layer was formed, the second layer was formed on the substrate, and then the first layer was formed on the second layer. The second layer was formed using the following procedure. The substrate temperature was set to 550°C, and the gas pressure in the apparatus was set to 4.0 Pa. A mixed gas of nitrogen gas and argon gas was introduced as the reactive gas. Then, an arc current of 150 A was supplied to the cathode electrode. The second layer was formed by generating metal ions and the like from the arc evaporation source by supplying the arc current.

[0080] When a third layer was formed, it was formed on the first layer. The third layer was formed using the following procedure. The substrate temperature was set to 550°C, and the gas pressure inside the apparatus was set to 4.0 Pa. A mixed gas of nitrogen gas and argon gas was introduced as the reactive gas. Then, an arc current of 150 A was supplied to the cathode electrode. The third layer was formed by generating metal ions and the like from the arc evaporation source by supplying the arc current.

[0081] In this manner, cutting tools for each sample were produced.

[0082]

[0083]

[0084] <Evaluation> <Measurement of Composition of First Layer> The composition of the first layer of each sample cutting tool was measured by the method described in embodiment 1. ａ Ti ｂ Cr(1-a-b-c-d)Si ｃ Cu ｄ The values ​​of a, b, c, and d in N are shown in Table 1. Furthermore, a+b+c+d and c / d are shown in Table 1.

[0085] <Measurement of Composition of Second Layer and Composition of Third Layer> For each sample cutting tool, the composition of the second layer and the third layer was measured by the method described in Embodiment 1. The results are shown in Table 2. In Table 2, "-" means that the corresponding layer does not exist.

[0086] <Measurement of Thickness of First Layer, Second Layer, and Third Layer> For each sample cutting tool, the thickness of the first layer, the thickness of the second layer, and the thickness of the third layer were measured by the method described in Embodiment 1. The results are shown in Tables 1 and 2.

[0087] <Crystalline Structure of Coating> The crystalline structure of the coating of each cutting tool sample was analyzed by the method described in embodiment 1. In samples 1 to 21, the crystalline structure was cubic.

[0088] <Hardness of Coating> The hardness of the coating of each sample cutting tool was analyzed by the method described in embodiment 1. In samples 1 to 21, the hardness of the coating was 30 GPa or more and 50 GPa or less.

[0089] <Cutting test> A continuous turning test was performed under the cutting conditions of each sample, and the cutting distance until the wear width or chipping width of the cutting edge reached 100 μm was measured. The results are shown in Table 2. A long cutting distance indicates a long tool life. <Cutting conditions> Workpiece: Inconel 718 Cutting speed Vc: 50 m / min Feed rate f: 0.25 mm / rev Depth of cut ap: 1.5 mm Cutting oil: Yes The above cutting conditions correspond to continuous machining of a nickel-based alloy.

[0090] The cutting tools of Samples 1 to 21 correspond to Examples, and the cutting tools of Samples 1-1 to 1-11 correspond to Comparative Examples. It was confirmed that the cutting tools of Samples 1 to 21 have a longer tool life in continuous machining of nickel-based alloys than the cutting tools of Samples 1-1 to 1-11.

[0091] Although the embodiments and examples of the present disclosure have been described above, it is intended from the beginning that the configurations of the above-described embodiments and examples may be appropriately combined or modified in various ways. The embodiments and examples disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims, not by the above-described embodiments and examples, and is intended to include meanings equivalent to the claims and all modifications within the scope of the claims.

[0092] 1 Cutting tool, 2 Substrate, 3 Coating, 13 First layer, 14 Second layer, 16 Third layer, 21 Rake face, 22 Flank face, 23 Cutting edge ridge, 101 Chamber, 103 Gas exhaust port, 104 Substrate holder, 105 Gas, 106, 107 Cathode, 108, 109 Arc power supply, 110 Bias power supply.

Claims

1. A cutting tool comprising a substrate and a coating provided on the substrate, wherein the coating includes a first layer, the first layer being Al ａ Ti ｂ Cr(1-a-b-c-d)Si ｃ Cu ｄ N, wherein the a, b, c, and d satisfy 0.50≦a≦0.75, 0.10≦b≦0.25, 0.005≦c≦0.20, 0.005≦d<0.10, and a+b+c+d<1.

2. The cutting tool according to claim 1, wherein c and d satisfy the relationship c / d≧1.

3. A cutting tool according to claim 1 or 2, wherein the thickness of said first layer is 0.5 μm or more and 10 μm or less.

4. A cutting tool according to any one of claims 1 to 3, wherein the coating further includes a second layer provided between the substrate and the first layer, and the second layer comprises at least one element selected from a first group consisting of Group 4 elements, Group 5 elements, Group 6 elements, aluminum, and silicon of the periodic table, or a first compound comprising at least one element selected from the first group and at least one element selected from a second group consisting of carbon, nitrogen, oxygen, and boron.

5. A cutting tool according to any one of claims 1 to 4, wherein the coating further includes a third layer provided on the first layer opposite the substrate, and the third layer consists of at least one element selected from a first group consisting of Group 4 elements, Group 5 elements, Group 6 elements, aluminum, and silicon of the periodic table, or a second compound consisting of at least one element selected from the first group and at least one element selected from a second group consisting of carbon, nitrogen, oxygen, and boron.

6. A cutting tool according to any one of claims 1 to 5, wherein the coating has a thickness of 0.5 μm or more and 12 μm or less.

7. A cutting tool according to any one of claims 1 to 6, wherein the substrate is made of cemented carbide, cermet, cubic boron nitride sintered body, diamond sintered body, high-speed steel, or ceramics.

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