Cutting tool

Abstract

A cutting tool provided with a base material and a coating film provided on the base material, the coating film including a first layer comprising AlaTibCr (1-a-b-c-d) SicAgdN, the a, b, c, and d satisfying 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

Technical Field

[0001] This disclosure relates to cutting tools. Background Technology

[0002] In the past, cutting tools with a substrate and a coating disposed on the substrate were used in cutting processes (Patent Document 1).

[0003] Existing technical documents Patent documents Patent document 1: Japanese Patent Application Publication No. 2003-71611. Summary of the Invention

[0004] The cutting tool disclosed herein comprises a substrate and a coating disposed on the substrate, wherein, The coating comprises a first layer. The first layer is composed of Al a Ti b Cr （1-a-b-c-d） Si c Ag d N constitutes, 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. Attached Figure Description

[0005] Figure 1 This is a schematic enlarged cross-sectional view of an example of the cutting tool involved in Embodiment 1.

[0006] Figure 2 This is a schematic enlarged cross-sectional view of an example of the cutting tool involved in Embodiment 1.

[0007] Figure 3 This is a schematic enlarged cross-sectional view of an example of the cutting tool involved in Embodiment 1.

[0008] Figure 4 This is a schematic enlarged cross-sectional view of an example of the cutting tool involved in Embodiment 1.

[0009] Figure 5 This is a perspective view illustrating one way of using a cutting tool.

[0010] Figure 6 This is a schematic cross-sectional view of the cathode arc ion plating apparatus used in the embodiment.

[0011] Figure 7 yes Figure 6 A schematic top view of the cathode arc ion plating apparatus shown. Detailed Implementation

[0012] [The problem this disclosure aims to solve] In recent years, the materials being machined have become more diverse, especially in the aerospace and medical fields, leading to an increase in the machining of nickel-based alloys, which are considered difficult to machine. When using cutting tools for continuous machining of nickel-based alloys, the tool tip temperature becomes very high, shortening the tool life. Therefore, there is a demand for cutting tools that can maintain a long tool life, particularly in the continuous machining of nickel-based alloys.

[0013] Therefore, the purpose of this disclosure is to provide a cutting tool that can have a long tool life, especially in the continuous machining of nickel-based alloys.

[0014] [The Effects of This Disclosure] According to this disclosure, it is possible to provide cutting tools that have a long tool life, especially in the continuous machining of nickel-based alloys.

[0015] [Description of embodiments of this disclosure] The embodiments of this disclosure are first described by listing them.

[0016] (1) The cutting tool of this disclosure comprises a substrate and a coating disposed on the substrate. The coating comprises a first layer. The first layer is composed of Al a Ti b Cr （1-a-b-c-d） Si c Ag d N constitutes, 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.

[0017] According to this disclosure, it is possible to provide cutting tools that have a long tool life, especially in the continuous machining of nickel-based alloys.

[0018] (2) In (1) above, it is also possible that c and d satisfy the relationship c / d≥1. As a result, the tool life is further improved.

[0019] (3) In (1) or (2) above, the thickness of the first layer may also be 0.5 μm or more and 10 μm or less. As a result, the tool life is further improved.

[0020] (4) In any of (1) to (3) above, the coating may also include a second layer disposed between the substrate and the first layer. The second layer is composed of at least one element selected from the first group consisting of elements from Group 4, Group 5, Group 6, aluminum, and silicon of the periodic table, or is composed of a first compound consisting of at least one element selected from the first group and at least one element selected from the second group consisting of carbon, nitrogen, oxygen, and boron.

[0021] As a result, the tool's lifespan is further extended.

[0022] (5) In any of (1) to (4) above, the coating may also include a third layer disposed on the side of the first layer opposite to the substrate. The third layer consists of at least one element selected from the first group consisting of elements from Group 4, Group 5, Group 6, aluminum, and silicon, or a second compound consisting of at least one element selected from the first group and at least one element selected from the second group consisting of carbon, nitrogen, oxygen, and boron.

[0023] As a result, the tool's lifespan is further extended.

[0024] (6) In any of (1) to (5) above, the thickness of the coating may be 0.5 μm or more and 12 μm or less. As a result, the tool life is further improved.

[0025] (7) In any of (1) to (6) above, the substrate may also be composed of cemented carbide, cermet, cubic boron nitride sintered body, diamond sintered body, high-speed steel or ceramic. As a result, the tool life is further improved.

[0026] [Details of the embodiments disclosed herein] Specific examples of the cutting tools of this disclosure will be described below with reference to the accompanying drawings. In the drawings of this disclosure, the same reference numerals denote the same or equivalent parts. Furthermore, changes to dimensional relationships such as length, width, thickness, and depth are made appropriately for clarity and simplification of the drawings and do not necessarily represent actual dimensional relationships.

[0027] In this disclosure, the expression "A~B" means that A is above and B is below, and where no unit is recorded in A but only in B, the unit of A is the same as the unit of B.

[0028] In this disclosure, when compounds are represented by chemical formulas, and there is no particular limitation on the atomic ratio, all previously known atomic ratios are included, and it should not be limited to atomic ratios within the stoichiometric range.

[0029] In this disclosure, when one or more values ​​are recorded as the lower limit and the upper limit of the numerical range, a combination of any value recorded at the lower limit and any value recorded at the upper limit is also disclosed.

[0030] [Implementation Method 1: Cutting Tool] like Figures 1-4 As shown, in one embodiment of this disclosure (hereinafter also referred to as "Embodiment 1"), the cutting tool 1 includes a substrate 2 and a coating 3 disposed on the substrate 2, wherein... The coating 3 includes a first layer 13. The first layer, 13, is composed of Al. a Ti b Cr （1-a-b-c-d） Si c Ag d N constitutes, 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.

[0031] The cutting tool of Embodiment 1 can also have a long tool life, especially in the continuous machining of nickel-based alloys. The reason for this is speculated as follows.

[0032] The aluminum (Al) contained in the first layer increases the high-temperature hardness of the first layer. When α is 0.50 or higher, the high-temperature hardness and heat resistance of the first layer are improved. When α is 0.75 or lower, the formation of hexagonal crystals is suppressed, thus preventing a decrease in the high-temperature hardness of the first layer.

[0033] The titanium (Ti) contained in the first layer improves the high-temperature strength of the first layer. When b is 0.10 or higher, the improvement in high-temperature strength is sufficiently achieved. When b is 0.25 or lower, the aluminum content of the first layer is sufficiently ensured, thus improving the high-temperature hardness of the first layer.

[0034] The first layer contains chromium (Cr) and aluminum, which improves the heat resistance and high-temperature oxidation resistance of the first layer.

[0035] The silicon (Si) contained in the first layer improves its oxidation resistance and heat resistance. The aforementioned c is 0.005 or higher, thereby improving the oxidation resistance of the first layer. Furthermore, the grain refinement of the first layer increases its hardness. The aforementioned c is 0.20 or lower, thereby suppressing the decrease in the toughness of the first layer and inhibiting the occurrence of cracking.

[0036] The silver (Ag) contained in the first layer forms an oxide film on the surface of the first layer, improving the lubricity of the coating. In addition, silver has low solubility relative to the components of nickel-based alloys, namely nickel and chromium (in the case of nickel-chromium alloys). Therefore, the first layer containing silver does not easily adhere to the workpiece material composed of nickel-based alloys during cutting.

[0037] On the other hand, silver does not form nitrides, and therefore tends to interfere with the lattice of nitride-based coatings, thus reducing the hardness of the coating. By adding silver and silicon to the first layer, the hardness of the first layer can be improved. This is an insight discovered by the inventors of this invention through in-depth research.

[0038] As described above, the first layer of Embodiment 1 can possess excellent high-temperature hardness and heat resistance based on aluminum, excellent high-temperature strength based on titanium, excellent oxidation resistance and heat resistance based on chromium and silicon, excellent lubricity and anti-adhesion properties based on silver, and high hardness based on the addition of silver and silicon, so that it can have a long tool life even in continuous machining of nickel-based alloys where the cutting tip is prone to high temperature during cutting.

[0039] <Cutting Tools> like Figures 1-4 As shown, the cutting tool 1 according to Embodiment 1 includes a substrate 2 and a coating 3 disposed on the substrate 2. The coating 3 can cover the entire surface of the substrate 2. In addition, even if a part of the substrate 2 is not covered by the coating 3, or if the composition of the coating 3 is partially different, it will not deviate from the scope of this embodiment. The coating 3 can also cover at least the portion of the substrate 2 that is involved in cutting. In this disclosure, the portion involved in cutting the substrate 2 is also related to the size and shape of the substrate 2, but the portion involved in cutting the substrate 2 refers to the area in the substrate 2 surrounded by an imaginary surface, which is for example 5 mm, 3 mm, 2 mm, 1 mm, or 0.5 mm away from the cutting edge and the perpendicular line from the cutting edge towards the substrate 2 along the tangent of the cutting edge.

[0040] The cutting tool 1 of this embodiment can preferably be used as a drill bit, end mill, indexable cutting insert for drill bit, indexable cutting insert for end mill, indexable cutting insert for milling, indexable cutting insert for turning, metalworking saw, gear cutting tool, reamer, tap, and other cutting tools 1.

[0041] Figure 5This is a perspective view illustrating one type of cutting tool. The cutting tool 1 is used as an indexable cutting insert. The cutting tool 1 has a rake face 21, a flank face 22, and a cutting edge 23 where the rake face 21 and the flank face 22 intersect.

[0042] <Substrate> As for the substrate, any previously known substrate can be used. For example, the substrate can be composed of any of the following: cemented carbide (WC-based cemented carbide, cemented carbide containing WC and Co, cemented carbide containing carbonitrides such as Ti, Ta, and Nb added to WC and Co), cermet (cermet with TiC, TiN, TiCN, etc. as the main components), high-speed steel, ceramics (titanium carbide, silicon carbide, silicon nitride, aluminum nitride, alumina, etc.), cubic boron nitride sintered body, or diamond sintered body.

[0043] In particular, the substrate can also be WC-based cemented carbide or cermet (especially TiCN-based cermet). WC-based cemented carbide or cermet has an excellent balance of hardness and strength, especially at high temperatures, and therefore can contribute to the long service life of cutting tools when used as a substrate.

[0044] <Lamination> The Composition of Coating The coating in Embodiment 1 comprises a first layer. The coating covers the substrate, thereby improving various properties such as wear resistance and chipping resistance of the cutting tool, and extending the tool's lifespan. Furthermore, the coating may also include other layers in addition to the first layer. These other layers could be, for example... Figures 2-4 As shown, examples include a second layer 14 disposed between the substrate 2 and the first layer 13, and a third layer 16 disposed on the side of the first layer 13 opposite to the substrate 2.

[0045] The thickness of the coating The coating thickness can 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. If the coating thickness is 0.5 μm or more, the life of the cutting tool can be further extended. On the other hand, if the overall coating thickness is 12 μm or less, the coating is less prone to cracking in the early stages of cutting, which can further extend the life of the cutting tool.

[0046] The thickness of the coating was determined by observing the cross-section of the coating using a scanning electron microscope (SEM). The specific measurement method is as follows: A cutting tool was used to cut along the normal direction of the main surface of the coating to prepare a cross-sectional sample. The cross-sectional sample was observed using SEM. The magnification was set to 5000~10000x, and the field of view was set to 100~500μm.2 The thickness of the coating is measured at three locations within a single field of view, and the average thickness of the three locations is calculated. This average value corresponds to the thickness of the coating. The thicknesses of the layers described later are measured using the same method unless otherwise specified.

[0047] Crystal Structures of Coated Layers The crystal structure of the coating can be cubic. If the coating has a cubic crystal structure, its hardness is increased. Alternatively, each layer in the coating (first layer, third layer, second layer, etc.) can have a cubic crystal structure. The crystal structure of the coating and its layers can be determined using X-ray diffraction equipment known in this field.

[0048] The Hardness of the Coating The hardness of the coating can be above 30 GPa and below 50 GPa, or above 35 GPa and below 45 GPa. Therefore, the coating possesses sufficient hardness. The hardness of the coating is determined by nanoindentation (measuring apparatus: ENT-1100a manufactured by Elionix). Specifically, according to the method of ISO 14577, the test load is set to 10 mN (1 gf), and the hardness is measured at ten locations on the surface of the coating. The average hardness of the ten locations is calculated. This average value corresponds to the hardness of the coating.

[0049] <First Layer> Composition of the First Layer The first layer consists of Al a Ti b Cr （1-a-b-c-d） Si c Ag d N is composed of a, b, c and d satisfying 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.

[0050] a can be greater than 0.500 and less than 0.750, greater than 0.550 and less than 0.700, or greater than 0.600 and less than 0.650.

[0051] b can be greater than or equal to 0.100 and less than 0.250, greater than or equal to 0.100 and less than 0.200, or greater than or equal to 0.120 and less than 0.180.

[0052] c can be greater than or equal to 0.005 and less than 0.200, greater than or equal to 0.010 and less than 0.150, or greater than or equal to 0.050 and less than 0.100.

[0053] d can be greater than or equal to 0.005 and less than 0.100, greater than or equal to 0.010 and less than 0.090, or greater than or equal to 0.030 and less than 0.080.

[0054] The sum of a, b, c, and d can be less than 1, and can be below 0.950, below 0.910, or below 0.890.

[0055] The c / d ratio can be above 1, greater than 1, above 1 but below 20, above 1.2 but below 10, above 1.25 but below 5, or above 2 but below 4. If the c / d ratio is above 1, the film hardness and tool life will increase.

[0056] In this disclosure, "the first layer is composed of Al" a Ti b Cr （1-a-b-c-d） Si c Ag d "N configuration" means that, without impairing the effects of this disclosure, the first layer can contain Al a Ti b Cr （1-a-b-c-d） Si c Ag d In addition to N, there are unavoidable impurities. Examples of unavoidable impurities include, for example, oxygen and carbon. The overall content of unavoidable impurities in the first layer can be greater than 0 atomic% and less than 1 atomic%. In this disclosure, "atomic%" refers to the proportion (%) of the number of atoms relative to the total number of atoms constituting the layer.

[0057] The content of impurities a, b, c, d, and the unavoidable impurities in the first layer was determined by elemental analysis of the cross-section of the coating using a transmission electron microscope (TEM). The specific method is as follows: A cutting tool is used to cut along the normal direction of the main surface of the coating, preparing a thin-section sample containing the coating cross-section. The thin-section sample is irradiated with electron beams using an EDS (Energy Dispersive X-ray Spectroscopy) device attached to the TEM. The energy and number of characteristic X-rays generated are measured to perform elemental analysis of the first layer. Five non-overlapping measurement regions are arbitrarily selected in the first layer, and elemental analysis is performed at these five regions. The average composition of the five regions is calculated. This average composition corresponds to the composition of the first layer. The compositions of the second and third layers, described later, are also determined using the same method. It was confirmed that even with arbitrary selection of measurement regions, the measurement results are unbiased.

[0058] In this disclosure, the composition of the first layer A1 a Ti bCr （1-a-b-c-d） Si c Ag d In N, the number of N atoms A N1 The total number of atoms of Al, Ti, Cr, Si, and Ag (A) M1 The ratio of A N1 / A M1 It is above 0.8 and below 1.2. Compared to A N1 / A M1 It can be determined using the Rutherford backscattering (RBS) method. The following condition was confirmed: if the above ratio A... N1 / A M1 If the scope is limited as described, the effect of this disclosure will not be impaired.

[0059] <Thickness of the first layer> The thickness of the first layer can 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. If the thickness of the first layer is 0.5 μm or more, it exhibits excellent wear resistance, which can further extend the life of the cutting tool. On the other hand, if the thickness of the first layer is 10 μm or less, it is less prone to cracking at the coating during the initial stage of cutting, which can further extend the life of the cutting tool.

[0060] <Second Layer> like Figure 2 as well as Figure 4 As shown, the coating 3 may further include a second layer 14 disposed between the substrate 2 and the first layer 13. The second layer 14 may be disposed directly above the substrate.

[0061] The second layer can be composed of at least one element selected from the first group consisting of elements from Group 4, Group 5, Group 6 of the periodic table, aluminum (Al), and silicon (Si), or it can be composed of a first compound, wherein the first compound is composed of at least one element selected from the first group and at least one element selected from the second group 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 the adhesion between the substrate and the coating, and increase tool life. Without impairing the effects of this disclosure, the second layer may contain unavoidable impurities in addition to including at least one element selected from the first group or the first compound.

[0062] The second layer may be composed of at least one element selected from Group 1A consisting of Cr, Al, Ti and Si, or of a first compound composed 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.

[0063] Examples of first compounds include, for example, TiWCN, TiN, TiAlN, TiAlON, Al2O3, TiAlSiN, TiCrSiN, TiAlCrSiN, AlCrN, AlCrO, AlCrON, AlCrSiN, AlCrBN, TiZrN, TiAlMoN, TiAlNbN, TiSiN, AlCrTaN, AlVN, AlTiVN, TiB2, TiCrHfN, CrSiWN, TiAlCN, TiSiCN, AlZrON, AlCrCN, AlHfN, CrSiBON, TiAlWN, AlCrMoCN, TiCN, TiCON, ZrN, and ZrCN.

[0064] The thickness of the second layer is not particularly limited within the range that does not impair the effect of this embodiment; for example, it can be set to be 0.1 μm or more and 2 μm or less.

[0065] <Third Layer> like Figure 3 as well as Figure 4 As shown, the coating 3 may also include a third layer 16 disposed on the side of the first layer 13 opposite to the substrate 2. The third layer 16 may be disposed directly above the first layer 13. Alternatively, other layers may be disposed between the first layer 13 and the third layer 16. The third layer 16 may also be the outermost layer.

[0066] The third layer may be composed of at least one element selected from the first group consisting of elements from Group 4, Group 5, Group 6 of the periodic table, aluminum (Al), and silicon (Si), or it may be composed of a second compound consisting of at least one element selected from the first group and at least one element selected from the second group consisting of carbon (C), nitrogen (N), oxygen (O), and boron (B). The third layer can reduce the coefficient of friction of the coating, thereby extending the life of the cutting tool. Without impairing the effects of this disclosure, the third layer may contain impurities in addition to containing at least one element selected from the first group or the aforementioned second compound.

[0067] The third layer may be composed of at least one element selected from Group 1A consisting of Cr, Al, Ti and Si, or a second compound composed 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.

[0068] Examples of second compounds include AlTiBN, TiAlN, TiAlON, Al2O3, TiAlSiN, TiCrSiN, TiAlCrSiN, AlCrN, AlCrO, AlCrON, AlCrSiN, AlCrBN, TiZrN, TiAlMoN, TiAlNbN, TiSiN, AlCrTaN, AlVN, AlTiVN, TiB2, TiCrHfN, CrSiWN, TiAlCN, TiSiCN, AlZrON, AlCrCN, AlHfN, CrSiBON, TiAlWN, AlCrMoCN, TiCN, TiCON, ZrN, and ZrCN.

[0069] The thickness of the third layer can be between 0.1 μm and 2 μm. If the thickness of the third layer is 0.1 μm or more, it is easy to obtain the lubrication effect based on the third layer. There is no particular upper limit to the thickness of the third layer, but if it exceeds 2 μm, there is a tendency that the above-mentioned lubrication effect cannot be further improved. Therefore, considering cost, the thickness of the third layer can be 2 μm or less.

[0070] <Intermediate Layer> The coating may include an intermediate layer disposed 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.

[0071] [Implementation Method 2: Method for Manufacturing a Cutting Tool] In Embodiment 2, a method for manufacturing the cutting tool of Embodiment 1 will be described. This 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.

[0072] <First Process> In the first step, a substrate is prepared. The substrate can be the one described in Embodiment 1. Any substrate that is conventionally known as a substrate can be prepared.

[0073] <Second Process> In the second process, a coating is formed on the substrate. The second process includes the process of forming the first layer.

[0074] In the process of forming the first layer, physical vapor deposition (PVD) is used. To improve the wear resistance of the coating containing the first layer, forming a layer composed of a highly crystalline compound is effective. The inventors of this invention investigated various methods as methods for forming the first layer and found that physical vapor deposition is the most effective.

[0075] As a PVD method, at least one selected from the group consisting of cathodic arc ion plating, balanced magnetron sputtering, unbalanced magnetron sputtering, and HiPIMS can be used. In particular, cathodic arc ion plating, which has a high ionization rate of the raw material element, can be used. When using cathodic arc ion plating, the surface of the substrate can be bombarded with metal ions before the formation of the first layer, thus significantly improving the adhesion between the substrate and the coating containing the first layer.

[0076] Cathodic arc ion plating can be performed as follows: After setting a substrate and a target as a cathode in the apparatus, a high voltage is applied to the target to generate an arc discharge, thereby ionizing and evaporating the atoms constituting the target, and depositing the material on the substrate.

[0077] <Other Processes> The second process may include surface treatment processes such as surface grinding and shot peening, in addition to the process of forming the first layer. Furthermore, the second process may include processes for forming other layers such as a second layer, a third layer, and intermediate layers. These other layers can be formed using conventional chemical vapor deposition (CVD) or physical vapor deposition (PVD). From the viewpoint that other layers can be formed continuously with the first layer within a single PVD apparatus, these other layers can be formed using PVD.

[0078] Example This embodiment will be further described in detail through examples. However, this embodiment is not limited to these examples.

[0079] Making Cutting Tools Figure 6 This is a schematic cross-sectional view of the cathode arc ion plating apparatus used in this embodiment. Figure 7 yes Figure 6 A schematic top view of the device.

[0080] exist Figure 6 as well as Figure 7 In the apparatus, an alloy target, namely a cathode 106 and 107, which serves as the metal raw material for the coating 3, is installed in the chamber 101, along with a rotating substrate holder 104 for setting the substrate. The composition of the cathodes 106 and 107 is adjusted to obtain the composition described in Table 1 below.

[0081] In the apparatus for forming a sample with a second or third layer, a cathode for the second layer or a cathode for the third layer (not shown) is also installed in chamber 101. The composition of the cathode for the second layer and the cathode for the third layer is adjusted to obtain the composition described in Table 2 below.

[0082] An arc power supply 108 is installed on cathode 106, and an arc power supply 109 is installed on cathode 107. Additionally, a bias power supply 110 is installed on substrate holder 104. Furthermore, a gas inlet 105 for introducing gas is provided inside chamber 101, and a gas outlet 103 is provided to regulate the pressure inside chamber 101, thus configuring the structure to allow gas to be drawn from chamber 101 through gas outlet 103 using a vacuum pump.

[0083] The substrate holder 104 is a cutting tool made of cemented carbide with a substrate assembly grade of JIS standard K20 and a shape of JIS standard CNMG120408.

[0084] Next, the pressure inside chamber 101 is reduced using a vacuum pump, and while the substrate is rotated, the temperature is heated to 500°C using a heater located within the device to perform evacuation until the pressure inside chamber 101 reaches 1.0 × 10⁻⁶. -4 Next, argon gas is introduced through the gas inlet to maintain the pressure inside chamber 101 at 2.0 Pa. The voltage of the bias power supply 110 is gradually increased until -1000V, and the surface of the substrate is cleaned for 15 minutes. Afterward, the argon gas is discharged from chamber 101, thereby cleaning the substrate (argon ion bombardment treatment). The substrate for preparing the cutting tools for each sample is thus obtained.

[0085] Next, while the substrate is rotated in the center, nitrogen gas is introduced as the reaction gas, and the substrate temperature is maintained at 550°C, the reaction gas pressure is maintained at 2.0 Pa, and the voltage of the bias power supply 110 is maintained at a constant value within the range of -50V to -300V. An arc current of 150A is supplied to the cathodes 106 and 107 respectively, so that metal ions are generated from the cathodes 106 and 107, thereby forming a first layer with the composition shown in Table 1 below on the substrate.

[0086] In the case where a second layer has been formed, a first layer is formed on the second layer after the second layer has been formed on the substrate. The second layer is formed through the following steps: The substrate temperature is set to 550°C and the gas pressure inside the apparatus is set to 4.0 Pa. A mixture of nitrogen and argon is introduced as the reaction gas. Then, an arc current of 150 A is supplied to the cathode electrode. Metal ions and the like are generated from the arc-type evaporation source by the supply of the arc current, thereby forming the second layer.

[0087] In the case where a third layer has been formed, a third layer is formed on top of the first layer. The third layer is formed through the following steps: The substrate temperature is set to 550°C and the gas pressure inside the apparatus is set to 4.0 Pa. A mixture of nitrogen and argon is introduced as the reaction gas. Then, an arc current of 150 A is supplied to the cathode electrode. Metal ions and the like are generated from the arc-type evaporation source by the supply of the arc current, thereby forming the third layer.

[0088] Based on the above, the cutting tools for each sample are made.

[0089] [Table 1]

[0090] [Table 2]

[0091] "evaluate" <Determination of the composition of the first layer> The composition of the first layer was determined using the method described in Embodiment 1, for each sample's cutting tool. The Al content of the first layer was... a Ti b Cr （1-a-b-c-d） Si c Ag 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.

[0092] <Determination of the composition of the second layer and the third layer> The composition of the second and third layers was determined using the method described in Embodiment 1 for each sample's cutting tool. The results are recorded in Table 2. A "-" in Table 2 indicates that the corresponding layer does not exist.

[0093] <Determination of the thickness of the first layer, the second layer, and the third layer> For each sample's cutting tool, the thicknesses of the first layer, the second layer, and the third layer were measured using the method described in Embodiment 1. The results are recorded in Tables 1 and 2.

[0094] <Crystal Structure of Coated Films> The crystal structure of the coating was analyzed using the method described in Embodiment 1, with respect to the cutting tool of each sample. In samples 1 to 21, the crystal structure was cubic.

[0095] <Film hardness> The hardness of the coating was analyzed using the method described in Example 1 for each sample's cutting tool. In samples 1 to 21, the hardness of the coating was 30 GPa or more and 50 GPa or less.

[0096] <Cutting Test> Continuous turning tests were performed under the cutting conditions of each specimen, and the cutting distance until the wear or chipping of the tool tip reached 200 μm was measured. The results are recorded in Table 2. A longer cutting distance indicates a longer tool life.

[0097] Cutting Conditions Material to be cut: INCONEL 718 Cutting speed Vc: 100m / min Feed rate f: 0.25 mm / rev Cut-in depth (ap): 2.0mm Cutting oil: Available The cutting conditions described above are equivalent to continuous machining of nickel-based alloys.

[0098] The cutting tools of specimens 1 to 21 are equivalent to the examples, and the cutting tools of specimens 1-1 to 1-11 are equivalent to the comparative examples. It was confirmed that the cutting tools of specimens 1 to 21 have a longer tool life in the continuous machining of nickel-based alloys compared to the cutting tools of specimens 1-1 to 1-11.

[0099] The embodiments and examples of this disclosure have been described above, but it is also intended from the outset that the above-described embodiments and examples may be appropriately combined or modified.

[0100] The embodiments and examples disclosed herein should be considered exemplary in all respects, and not restrictive. The scope of the invention is defined not by the foregoing embodiments and examples, but by the claims, and is intended to include all modifications equivalent to and within the scope of the claims.

[0101] Explanation of reference numerals in the attached figures 1: Cutting tool; 2: Substrate; 3: Coating; 13: First layer; 14: Second layer; 16: Third layer; 21: Rake face; 22: Back face; 23: Tool tip edge; 101: Chamber; 103: Gas outlet; 104: Substrate holder; 105: Gas; 106, 107: Cathode; 108, 109: Arc power supply; 110: Bias power supply.

Claims

1. A cutting tool, the cutting tool comprising a substrate and a coating disposed on the substrate, wherein, The coating comprises a first layer. The first layer is composed of Al a Ti b Cr （1-a-b-c-d） Si c Ag d N constitutes, 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, The c and the d satisfy the relationship c / d≥1.

3. The cutting tool according to claim 1 or 2, wherein, The thickness of the first layer is greater than 0.5 μm and less than 10 μm.

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

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

6. The cutting tool according to any one of claims 1 to 5, wherein, The thickness of the coating is greater than 0.5 μm and less than 12 μm.

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

Images