COATED TOOL AND CUTTING TOOL

Abstract

A coated tool comprises a base body and a coating layer disposed on the base body. The coating layer comprises an intermediate layer and a wear-resistant layer disposed on the intermediate layer. The ratio of the average grain diameter of the crystal grains forming the wear-resistant layer to the average grain diameter of the crystal grains forming the intermediate layer is 0.7 or less.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a coated tool and a cutting tool. BACKGROUND OF THE INVENTION

[0002] Known tools used for cutting operations such as turning or milling have a coated tool in which a surface of a base body made of cemented carbide, cermet, ceramic or the like is coated with a coating layer to improve wear resistance and the like. CITATION LISTPATENT LITERATURE

[0003] Patent Document 1: WO 2016 / 017790 BRIEF EXPLANATION

[0004] According to one aspect of the present disclosure, a coated tool is provided that includes a base body and a coating layer disposed on the base body. The coating layer includes an intermediate layer and a wear-resistant layer disposed on the intermediate layer. The ratio of an average grain diameter of crystal grains forming the wear-resistant layer to an average grain diameter of crystal grains forming the intermediate layer is 0.7 or less. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing an example of a coated tool according to an embodiment. Fig. 2 is a side cross-sectional view showing an example of a coated tool according to the embodiment. Fig.3 is a schematic enlarged view of a corner portion of a tip body according to a reference example. Fig. 4 is a cross-sectional view showing an example of a coating layer according to the embodiment. Fig. 5 is a front view showing an example of a cutting tool according to the embodiment. Fig. 6 is a graph showing a correlation between a cutting time and an abrasive wear amount. Fig. 7 is a diagram showing a cutting edge state of a coated tool according to an example after a cutting test. Fig. 8 is a picture showing a cutting edge state of a coated tool according to a comparative example after a cutting test. DESCRIPTION OF THE EMBODIMENTS

[0005] The following is a detailed description of embodiments of a coated tool and a cutting tool according to the present disclosure (hereinafter referred to as "embodiments") with reference to the drawings. The coated tool and the cutting tool according to the present disclosure are not limited by the embodiments. The embodiments can be combined as appropriate within the scope of the present disclosure without causing any substantive contradiction. In the following embodiments, like portions are designated by like reference numerals, and redundant explanations are omitted.

[0006] Known tools used for cutting operations such as turning or milling have a coated tool in which a surface of a base body made of cemented carbide, cermet, ceramic or the like is coated with a coating layer to improve wear resistance and the like.

[0007] The related technology mentioned above offers room for further improvements in terms of improving wear resistance.

[0008] Therefore, there is a need for a technology that can overcome the above problems and improve wear resistance. Coated tool

[0009] Fig. 1 is a perspective view showing an example of a coated tool according to an embodiment. Fig. 2 is a side cross-sectional view showing an example of the coated tool according to the embodiment. As shown in Fig.1, the coated tool 1 according to the embodiment has a tip body 2. Lace body 2

[0010] The tip body 2 has a hexagonal shape, in which an upper surface and a lower surface (surfaces which have a Fig. 1) have the shape of a parallelogram.

[0011] A corner portion 201 of the tip body 2 functions as a cutting edge portion. The cutting edge portion has a first surface (e.g., a top surface) and a second surface (e.g., a side surface) connected to the first surface. In the embodiment, the first surface functions as a "chip surface" for collecting chips generated during cutting, and the second surface functions as a "clearance surface." A cutting edge is disposed at least on a part of a ridge line where the first surface and the second surface intersect, and the coated tool 1 cuts a workpiece by applying the cutting edge to the workpiece.

[0012] In the central portion of the tip body 2, a through hole 5 is arranged, which penetrates the tip body 2 vertically. A screw 75 for fastening the coated tool 1 to a holder 70 (described later) is inserted into the through hole 5 (see Fig. 5).

[0013] The Fig. The shape of the coated tool 1 shown in FIG. 1 is merely an example and does not limit the shape of the coated tool according to the present disclosure. The coated tool according to the present disclosure may include a body having, for example, a rotation axis and a rod-like shape extending from a first end to a second end, a cutting edge disposed at the first end of the body, and a groove extending helically from the cutting edge to the second end of the body.

[0014] As in Fig. 2, the tip body 2 has a base body 10 and a coating layer 20. Base body 10

[0015] The base body 10 is made, for example, from a cemented carbide alloy. The cemented carbide alloy contains a hard phase containing at least tungsten (W), in particular tungsten carbide (WC). The cemented carbide alloy may contain a binder phase containing at least one iron group element such as nickel (Ni) or cobalt (Co). The base body 10 is made, for example, from a WC-based cemented carbide alloy with hard particles, which is made of WC as a hard phase component and Co as a main component of a binder phase. When the base body 10 is made from a cemented carbide alloy, the base body 10 has better heat-resistant properties.

[0016] The base body 10 can be made of a cermet. The cermet contains, for example, titanium (Ti), in particular titanium carbide (TiC) or titanium nitride (TiN). The cermet can contain Ni or Co.

[0017] The base body 10 can be made of a sintered body of cubic boron nitride containing particles of cubic boron nitride (cBN). The base body 10 can contain not only particles of cubic boron nitride (cBN), but also particles of, for example, hexagonal boron nitride (hBN), rhombohedral boron nitride (rBN), or wurtzite boron nitride (wBN).

[0018] The base body 10 can be made of ceramic. The ceramic contains, for example, aluminum oxide (Al2O3), such as κ-Al2O3 and α-Al2O3. The ceramic can also contain other elements in the aluminum oxide. For example, in addition to aluminum oxide, the ceramic can contain at least one element selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), silicon (Si), and elements of group 3 of the periodic table. Coating layer 20

[0019] The coating layer 20 covers the base body 10 to improve the wear resistance, heat resistance, and the like of the base body 10. In the example in Fig. 2, the coating layer 20 completely covers the base body 10. The arrangement of the coating layer 20 on the base body 10 is not particularly limited, as long as the coating layer 20 is arranged at least on the upper surface of the base body 10. When the coating layer 20 is arranged on the first surface (here, the upper surface) of the base body 10, the first surface has high wear resistance and heat resistance. When the coating layer 20 is arranged on the second surface (here, the side surface) of the base body 10, the second surface has high wear resistance and heat resistance. Damage to the tip body

[0020] Here, damage caused to the tip body is assessed using Fig.3 described. Fig. 3 is a schematic enlarged view of a corner portion 201X of a tip body 2X according to a reference example.

[0021] As in Fig. As shown in Figure 3, the tip body 2X may be subject to wear such as primary edge wear D1, secondary edge wear D2, abrasion wear D3, and crater wear D4. Primary edge wear D1, secondary edge wear D2, and abrasion wear D3 are wear occurring on a flank surface, and crater wear D4 is wear occurring on a rake surface.

[0022] D3 abrasive wear is a wear phenomenon in which the surface of the 2X tip body is abraded by foreign material located between the 2X tip body and the workpiece. D3 abrasive wear can cause an increase in cutting resistance and cutting heat.

[0023] Primary edge wear D1 and secondary edge wear D2 are wear that occurs at the two end portions of the abrasive wear D3, i.e., at the cutting boundary. The primary boundary is the boundary that comes into contact with the cutting surface of the workpiece, and the secondary boundary is the boundary that comes into contact with the finished surface of the workpiece. Primary edge wear D1 can lead to burr formation on the workpiece. Secondary edge wear D2 can deteriorate the finished surface of the workpiece and change the dimensions of the workpiece.

[0024] D4 crater wear is a type of wear that occurs when the surface of the tip body is oxidized by high temperatures, resulting in the formation of relatively soft oxides. D4 crater wear can impair chip controllability.

[0025] In the coated tool 1 according to the embodiment, the configuration of the coating layer 20 covering the tip body 2 is arranged so that this damage can be suitably reduced. Coating layer configuration 20

[0026] Here, an example of the configuration of the coating layer 20 according to the embodiment will be explained with reference to Fig. 4 described. Fig. 4 is a cross-sectional view showing an example of the coating layer 20 according to the embodiment.

[0027] As in Fig.As shown in Figure 4, the coating layer 20 includes an adhesion layer 21, an intermediate layer 22, and a wear-resistant layer 23. The adhesion layer 21 is a layer in contact with the base body 10. The intermediate layer 22 is disposed on the surface of the adhesion layer 21. The wear-resistant layer 23 is disposed on the surface of the intermediate layer 22. That is, the adhesion layer 21, the intermediate layer 22, and the wear-resistant layer 23 are stacked in the order of the adhesion layer 21, the intermediate layer 22, and the wear-resistant layer 23 from the surface side of the base body 10.

[0028] The adhesion layer 21 is an alloy layer containing Ti a Al b M cM is at least one metal selected from groups 4a, 5a, and 6a of the Periodic Table and S. The atomic ratio of a and b is such that 40 ≤ a ≤ 80 and 0 ≤ b ≤ 55, and a + b + c = 100. The adhesion layer 21 may be, for example, TiAlWNbSi.

[0029] The adhesion layer 21 does not necessarily have to contain M. In this case, the adhesion layer 21 can be TiAl, for example. The adhesion layer 21 improves the adhesion of the coating layer 20 to the base body 10. As a result, the adhesion layer 21 can reduce the occurrence of primary edge wear D1 and secondary edge wear D2 in the tip body 2.

[0030] The intermediate layer 22 contains Ti d Al e M fand at least one non-metal selected from carbon, nitrogen, and oxygen. M is at least one metal selected from groups 4a, 5a, and 6a of the Periodic Table (except Cr) and Si. d and e are 0 ≤ d ≤ 55 and 40 ≤ e ≤ 80, and d + e + f = 100. The intermediate layer 22 can be, for example, TiAlWNbSiN.

[0031] The intermediate layer 22 does not necessarily have to contain M. In this case, the intermediate layer 22 can be TiAlN, for example. The intermediate layer 22 has high oxidation resistance. As a result, the intermediate layer 22 can reduce the occurrence of crater wear D4 in the tip body 2.

[0032] The wear-resistant layer 23 contains Ti g Al h Cr i M jand at least one non-metal selected from carbon, nitrogen, and oxygen. M is at least one metal selected from groups 4a, 5a, and 6a of the Periodic Table (except Cr) and Si. The atomic ratio of g to j is such that 15 ≤ g ≤ 40, 50 ≤ h ≤ 70, and 5 ≤ i ≤ 20, and g + h + i + j = 100. The wear-resistant layer 23 can be, for example, TiAlCrWNbSiN.

[0033] The wear-resistant layer 23 does not necessarily contain M. In this case, the wear-resistant layer 23 may be TiAlCrN, for example. The wear-resistant layer 23 is a layer that comes into contact with the workpiece when the workpiece is cut with the coated tool 1 and can reduce the occurrence of primary edge wear D1, secondary edge wear D2, and abrasive wear D3 in the tip body 2.

[0034] The adhesion layer 21, the intermediate layer 22, and the wear-resistant layer 23 may each contain Ti and Al as the main components. The term "main component" here means that the content in atomic percent is higher than that of the other components contained. When Ti and Al are contained as the main components, high wear resistance and high chipping resistance can be achieved. When the intermediate layer 22 and the wear-resistant layer 23 each contain Ti and Al as the main components, the difference in thermal expansion between the adhesion layer 21, the intermediate layer 22, and the wear-resistant layer 23 can be kept small. Therefore, cracks are unlikely to occur at the interface between the adhesion layer 21 and the intermediate layer 22, as well as at the interface between the intermediate layer 22 and the wear-resistant layer 23.

[0035] Based on the above description, it is clear that M c in the adhesion layer 21, M f in the intermediate layer 22 and M j in the wear-resistant layer 23 do not have to be limited to a specific metal element or to a specific content.

[0036] The proportions of the metal components in the adhesion layer 21, the intermediate layer 22 and the wear-resistant layer 23 can be determined, for example, by analysis with an energy dispersive X-ray spectrometer (EDS) connected to a scanning transmission electron microscope (STEM).

[0037] The thickness of the coating layer 20 can be 2.5 μm or more and 10 μm or less. When the thickness of the coating layer 20 is 2.5 μm or more, wear resistance (especially abrasion wear resistance D3) can be more easily ensured. When the thickness of the coating layer 20 is 10 μm or less, chipping of the coating layer 20 can be more easily reduced. Therefore, when the thickness of the coating layer 20 is 2.5 μm or more and 10 μm or less, the wear resistance and chipping resistance of the coating layer 20 can be improved.

[0038] The thickness of the adhesion layer 21 may be 2 nm or more and 8 nm or less. When the thickness of the adhesion layer 21 is 2 nm or more, the adhesion of the coating layer 20 to the base body 10 can be more easily improved. The occurrence of primary interface wear D1 and secondary interface wear D2 in the tip body 2 can be more easily reduced. On the other hand, when the thickness of the adhesion layer 21 is 8 nm or less, breakage of the coating layer 20 can be more easily reduced by reducing the plastic deformation of the adhesion layer 21, which is relatively soft. Therefore, when the thickness of the adhesion layer 21 is 2 nm or more and 8 nm or less, the occurrence of primary edge wear D1 and secondary edge wear D2 in the tip body 2 and the breakage of the coating layer 20 can be reduced.

[0039] The thickness of the intermediate layer 22 may be less than the thickness of the wear-resistant layer 23. For example, the thickness of the intermediate layer 22 may be 0.5 μm or more and 3 μm or less. When the thickness of the intermediate layer 22 is 0.5 μm or more, the occurrence of crater wear D4 in the tip body 2 can be more easily reduced. On the other hand, when the thickness of the intermediate layer 22 is 3 μm or less, the effect of the wear-resistant layer 23 in reducing the occurrence of primary edge wear D1, secondary edge wear D2, and abrasive wear D3 in the tip body 2 can be more easily ensured. Therefore, when the thickness of the intermediate layer 22 is 0.5 μm or more and 3 μm or less, the damage to the tip body 2 can be more easily reduced.

[0040] The thickness of the wear-resistant layer 23 may be 1.5 μm or more and 7 μm or less. When the thickness of the wear-resistant layer 23 is 1.5 μm or more, the occurrence of primary edge wear D1, secondary edge wear D2, and abrasive wear D3 in the tip body 2 can be more easily reduced. On the other hand, when the thickness of the intermediate layer 22 is 7 μm or less, the effect of the intermediate layer 22 in reducing the occurrence of crater wear D4 in the tip body 2 can be more easily ensured. Therefore, when the thickness of the wear-resistant layer 23 is 1.5 μm or more and 7 μm or less, the damage to the tip body 2 can be more easily reduced.

[0041] Here, an example is shown in which the coating layer 20 is formed of the adhesion layer 21, the intermediate layer 22, and the wear-resistant layer 23; however, the coating layer 20 does not necessarily have to include the adhesion layer 21. For example, when the coating layer 20 has high adhesion to the base body and / or when it is a workpiece in which primary edge wear D1 and secondary edge wear D2 are unlikely to occur, the coated tool 1 may include a coating layer 20 including an intermediate layer 22 disposed on the surface of the base body 10 and a wear-resistant layer 23 disposed on the surface of the intermediate layer 22.

[0042] In the coating layer 20 according to the present embodiment, the ratio of an average grain diameter W23 of crystal grains forming the wear-resistant layer 23 to an average grain diameter W22 of crystal grains forming the intermediate layer 22 is 0.7 or less. The ratio of the average grain diameter W23 of crystal grains forming the wear-resistant layer 23 to the average grain diameter W22 of crystal grains forming the intermediate layer 22 is, for example, 0.5 or less, and may be 0.15 or less.

[0043] Here, the average grain diameter W22 of crystal grains forming the intermediate layer 22 and the average grain diameter W23 of crystal grains forming the wear-resistant layer 23 can be determined, for example, as follows. First, a scanning transmission electron microscope (STEM) or the like is used to photograph a cross-section of the coating layer 20 comprising the intermediate layer 22 and the wear-resistant layer 23 in a direction perpendicular to the surface of the base body 10. Then, in the cross-section of the coating layer 20, the maximum diameter and the minimum diameter of each of a predetermined number of crystal grains forming the intermediate layer 22 or the wear-resistant layer 23 are determined.Particles with a maximum diameter of less than 3 nm are excluded from the evaluation target because it is difficult to judge whether they are crystal grains or not.

[0044] Next, the average value of the maximum and minimum diameters of the crystal grains is calculated as the grain diameter of the crystal grains. Then, the average value of the grain diameters of a predetermined number of crystal grains is calculated as the average grain diameter of the crystal grains. The predetermined number is, for example, a number that can be used to determine the average grain diameter of the crystal grains with approximately three significant figures.

[0045] When the ratio of the average grain diameter W23 of crystal grains forming the wear-resistant layer 23 to the average grain diameter W22 of crystal grains forming the intermediate layer 22 is 0.7 or less, the average grain diameter W23 of crystal grains forming the wear-resistant layer 23 can be relatively reduced. This can reduce the occurrence of cracks in the wear-resistant layer 23. On the other hand, the average grain diameter W22 of crystal grains forming the intermediate layer 22 can be relatively increased. This can reduce the propagation of cracks in the intermediate layer 22.

[0046] When both the average grain diameter W22 of crystal grains constituting the intermediate layer 22 and the average grain diameter W23 of crystal grains constituting the wear-resistant layer 23 are small, the occurrence of cracks in the wear-resistant layer 23 can be reduced, but it may become difficult to reduce the propagation of cracks in the intermediate layer 22. When both the average grain diameter W22 of crystal grains constituting the intermediate layer 22 and the average grain diameter W23 of crystal grains constituting the wear-resistant layer 23 are large, the propagation of cracks in the intermediate layer 22 can be reduced, but it may become difficult to reduce the occurrence of cracks in the wear-resistant layer 23.

[0047] When the ratio of the average grain diameter W23 of crystal grains constituting the wear-resistant layer 23 to the average grain diameter W22 of crystal grains constituting the intermediate layer 22 is 0.7 or less, both the occurrence of cracks in the wear-resistant layer 23 and the propagation of cracks in the intermediate layer 22 can be reduced. This can improve the wear resistance of the coated tool 1. For example, the wear resistance of the coated tool 1 can be improved when machining a heat-resistant alloy. This can extend the tool life of the coated tool 1.

[0048] In the coating layer 20 according to the present embodiment, the ratio of the average grain diameter W23 of crystal grains forming the wear-resistant layer 23 to the average grain diameter W22 of crystal grains forming the intermediate layer 22 can be 0.05 or greater. In this case, the relative increase in the average grain diameter W22 of crystal grains forming the intermediate layer 22 with respect to the average grain diameter W23 of crystal grains forming the wear-resistant layer 23 can be reduced. Therefore, the occurrence of cracks in the intermediate layer 22 can be reduced. This enables a further improvement in the wear resistance of the coated tool 1.

[0049] The average grain diameter W22 of crystal grains forming the intermediate layer 22 can be 100 nm or less. In this case, the occurrence of cracks in the intermediate layer 22 can be reduced. This can further improve the wear resistance of the coated tool 1. The average grain diameter W22 of crystal grains forming the intermediate layer 22 can be 70 nm or less. In this case, the occurrence of cracks in the intermediate layer 22 can be further reduced.

[0050] The average grain diameter W23 of crystal grains forming the wear-resistant layer 23 can be 70 nm or less. In this case, the occurrence of cracks in the wear-resistant layer 23 can be further reduced. This can further improve the wear resistance of the coated tool 1. The average grain diameter W23 of crystal grains forming the wear-resistant layer 23 can be 50 nm or less. In this case, the occurrence of cracks in the wear-resistant layer 23 can be further reduced. The average grain diameter W23 of crystal grains forming the wear-resistant layer 23 can be 10 nm or less. In this case, the occurrence of cracks in the wear-resistant layer 23 can be further reduced.

[0051] Among the coating layers 20 according to the present embodiment, the one disposed on the corner portion 201 of the tip body 2 is referred to as a coating layer (first layer) 20A, the one disposed on the first surface (rake surface) of the tip body 2 is referred to as a coating layer (second layer) 20B, and the one disposed on the second surface (flank surface) of the tip body 2 is referred to as a coating layer (third layer) 20C. The average grain diameter of the crystal grains in the coating layers 20A, 20B, and 20C will be described below.

[0052] However, the average grain diameter of the crystal grains in the coating layer 20A can be evaluated at a location located on a ridge line where the first surface and the second surface intersect. The average grain diameter of the crystal grains in the coating layer 20B can be determined at a location on the first surface that is 500 µm away from the above-mentioned ridge line. The average grain diameter of the crystal grains in the coating layer 20C can be determined at a location on the second surface that is 500 µm away from the above-mentioned ridge line.

[0053] In each of the coating layers 20A, 20B, and 20C, the ratio of the average grain diameters W23A, W23B, and W23C of crystal grains constituting the wear-resistant layer 23 to the average grain diameters W22A, W22B, and W22C of crystal grains constituting the intermediate layer 22 may be 0.7 or less. In other words, the values ​​of W23A / W22A, W23B / W22B, and W23C / W22C may each be 0.7 or less. In this case, the wear resistance of each of the cutting edge, rake face, and flank face is improved.

[0054] W23A / W22A, W23B / W22B, and W23C / W22C can have the same value or be different. W23A / W22A can be greater than W23B / W22B and W23C / W22C. For example, the ratios of W23A / W22A to W23B / W22B and W23C / W22C can be 1.05 or more.

[0055] High wear resistance is required for the coating layer 20B on the rake face and the coating layer 20C on the flank face. When W23B / W22B and W23C / W22C are relatively small, high wear resistance can be achieved on the rake face and flank face. On the other hand, the coating layer 20A on the cutting edge must have high chipping resistance in addition to wear resistance. When W23A / W22A is relatively large, high chipping resistance can be ensured at the cutting edge. Therefore, the coated tool 1 can have high durability overall.

[0056] W23B / W22B and W23C / W22C can have the same value or be different from each other. W23B / W22B can be smaller than W23C / W22C. For example, the ratio of W23B / W22B to W23C / W22C can be 0.95 or less. The rake face that comes into contact with the chips is more susceptible to wear than the flank face. Therefore, if W23B / W22B in the coating layer 20B disposed on the wear-prone rake face is smaller than W23C / W22C, the service life of the coated tool 1 is improved.

[0057] W23C / W22C can be smaller than W23B / W22B. For example, the ratio of W23C / W22C to W23B / W22B can be 0.95 or less. If W23C / W22C in the coating layer 20C, which is located on the flank opposite the finished surface of the workpiece, is smaller than W23B / W22B, the surface accuracy of the finished surface of the workpiece can be improved.

[0058] The average grain diameter W23A in the coating layer 20A can be larger than the average grain diameter W23B in the coating layer 20B and the average grain diameter W23C in the coating layer 20C. For example, the ratio of W23A to W23B and W23C can be 1.1 or greater. When W23A is relatively large, high chipping resistance can be ensured at the cutting edge. Therefore, the coated tool 1 can have high overall durability.

[0059] For the same reason, the average grain diameter W22A in the coating layer 20A can be larger than the average grain diameter W22B in the coating layer 20B and the average grain diameter W22C in the coating layer 20C. For example, the ratio of W22A to W22B and W22C can be 1.05 or greater. When W22A is relatively large, high chipping resistance can be ensured at the cutting edge. Therefore, the coated tool 1 can have a long overall service life. In this case, the ratio of W23A to W23B and W23C can be larger than the ratio of W22A to W22B and W22C. Method for producing the coating layer 20

[0060] An example of a method for manufacturing the coating layer 20 according to the present embodiment will be described. The method for manufacturing the coating layer 20 according to the present embodiment is not limited to the following manufacturing method.

[0061] The coating layer 20 can be formed, for example, by a physical vapor deposition (PVD) method. When the coating layer 20 is formed, for example, by a physical vapor deposition method while the base body 10 is held against an inner peripheral surface of the through-hole 5, the coating layer 20 can be formed to cover the entire surface of the base body 10 except for the inner peripheral surface of the through-hole 5.

[0062] Examples of the physical vapor deposition method include an ion plating method, such as an arc ion plating (AIP) method, and a sputtering method. The arc ion plating method is a method in which a target metal is evaporated using an arc discharge in a vacuum atmosphere and then, if necessary, combined with N2 gas or the like to form a layer of a metal or metal nitride. At this time, the bias voltage applied to the base body 10 to be coated may be -30 V or less.

[0063] As an example, when the coating layer 20 is formed by the arc ion plating method, the coating layer 20 can be formed by the following method.

[0064] First, an example of a method for producing the adhesion layer 21 will be described. As an example, a metal target, a composite alloy target, or a sintered target made of Ti, Al, and M (here, M is at least one metal selected from the group consisting of metals of Groups 4a, 5a, and 6a of the Periodic Table and Si) is prepared.

[0065] Then, the target serving as the metal source is vaporized and ionized by arc discharge, glow discharge, or similar, and the ionized metal is vapor-deposited onto the surface of the base body 10. The adhesion layer 21 can be formed by the above process.

[0066] The composition of the adhesion layer 21 can be adjusted by independently controlling the voltage or current value during the arc discharge or glow discharge applied to each of the different metal targets. The composition of the adhesion layer 21 can also be adjusted by controlling the composition of the metal target, the deposition time, or the atmospheric gas pressure. The thickness of the adhesion layer 21 can be adjusted, for example, by controlling the deposition time.

[0067] Next, an example of a method for manufacturing the intermediate layer 22 will be described. As an example, a metal target, a composite alloy target, or a sintered target made of Ti, Al, and M (here, M is at least one metal selected from the group consisting of metals of Groups 4a, 5a, and 6a of the Periodic Table (except Cr) and Si) is prepared.

[0068] Then, the target serving as the metal source is evaporated and ionized by arc discharge, glow discharge, or the like. The ionized metal is reacted with a nitrogen (N2) gas or the like and evaporated onto the surface of the base body 10. The intermediate layer 22 can be formed by the above process.

[0069] The composition of the intermediate layer 22 can be adjusted by controlling the composition of the metal target. The grain diameter of the intermediate layer 22 can be adjusted by controlling the current value during the arc discharge or glow discharge, or by controlling the atmospheric gas pressure. The thickness of the intermediate layer 22 can be adjusted, for example, by controlling the deposition time.

[0070] Next, a method for manufacturing the wear-resistant layer 23 will be described. As an example, a metal target, a composite alloy target, or a sintered target made of Ti, Al, Cr, and M (here, M is at least one metal selected from the group consisting of metals of groups 4a, 5a, and 6a of the periodic table (except Cr) and Si) is prepared.

[0071] Then, the target serving as the metal source is vaporized and ionized by arc discharge, glow discharge, or the like. The ionized metal is reacted with nitrogen (N2) gas or the like and vapor-deposited onto the surface of the base body 10. The wear-resistant layer 23 can be formed by the above process.

[0072] The composition of the wear-resistant layer 23 can be adjusted by controlling the composition of the metal target. The grain diameter of the wear-resistant layer 23 can be adjusted by controlling the voltage or current value during the arc discharge or glow discharge, or by controlling the atmospheric gas pressure. The thickness of the wear-resistant layer 23 can be adjusted, for example, by controlling the coating time. Cutting tool

[0073] The configuration of a cutting tool having the above-mentioned coated tool 1 will be described with reference to Fig. 5 described. Fig. 5 is a front view showing an example of a cutting tool according to the embodiment.

[0074] As in Fig. 5, a cutting tool 100 according to the embodiment includes a coated tool 1 and a holder 70 for fixing the coated tool 1.

[0075] The holder 70 is a rod-shaped element extending from a first end (the upper end in Fig. 5) to a second end (the lower end in Fig. 5). The holder 70 is made of, for example, steel or cast iron. In particular, high-toughness steel can be used among these elements.

[0076] The holder 70 has a pocket 73 at a portion on the first end side. The pocket 73 is a portion to which the coated tool 1 is attached. The pocket 73 has a seating surface that intersects the rotation direction of the workpiece and has a retaining side surface that is inclined with respect to the seating surface. The seating surface is formed with a screw hole into which the screw 75 described below is screwed.

[0077] The coated tool 1 is arranged in the pocket 73 of the holder 70 and is fixed to the holder 70 with the screw 75. That is, the screw 75 is inserted into the through hole 5 of the coated tool 1, and the tip of the screw 75 is inserted into the screw hole formed in the seat surface of the pocket 73, so that the threaded portions are screwed together. In this way, the coated tool 1 is fixed to the holder 70 such that the cutting edge portion protrudes outward from the holder 70.

[0078] In the embodiment, a cutting tool 100 used for so-called turning machining is shown as an example. Examples of turning machining include inner diameter machining, outer diameter machining, and grooving machining. The cutting tool is not limited to a cutting tool for turning machining. The coated tool 1 can also be used, for example, as a cutting tool for milling machining. Examples of cutting tools that can be used for milling machining include milling cutters such as flat cutters, face cutters, side cutters, and slot cutters, as well as end mills such as single-flute end mills, multi-flute end mills, taper end mills, and ball cutters. EXAMPLES

[0079] An example of the present disclosure is described in more detail below. The present disclosure is not limited to the following example. Example

[0080] As an example, a coated tool comprising a base body and a coating layer with an adhesion layer, an intermediate layer, and a wear-resistant layer was manufactured by stacking an adhesion layer, an intermediate layer, and a wear-resistant layer on a base body using an arc ion plating process. A WC-based cemented carbide alloy was used as the base body. The compositions and thicknesses of the adhesion layer, the intermediate layer, and the wear-resistant layer formed on the base body are listed in Table 1. Table 1 Table 1 composition Thickness (µm) Adhesive layer The 40 Al 45 W5Nb5Si5 0,005 Intermediate layer <h2 style=";text-align:left;direction:ltr">Ti<h2 style=";text-align:left;direction:ltr"> 40 <h2 style=";text-align:left;direction:ltr"> Al<h2 style=";text-align:left;direction:ltr"> 45 <h2 style=";text-align:left;direction:ltr"> W5Nb5Si5N 3,000 wear-resistant layer The 20 Al 55 Cr 10 W5Nb5Si5N 5,000

[0081] Subsequently, using a scanning transmission electron microscope, the maximum and minimum diameters of the crystal grains forming the intermediate layer, as well as the maximum and minimum diameters of the crystal grains forming the wear-resistant layer, were measured at the cutting edge of the coated tool produced as an example. The grain diameters of the crystal grains forming the intermediate layer and the grain diameters of the crystal grains forming the wear-resistant layer were then calculated. The ratio of the average grain diameter of the crystal grains forming the wear-resistant layer to the average grain diameter of the crystal grains forming the intermediate layer was calculated.

[0082] For the manufactured samples No. 1 to No. 11, the values ​​of the maximum diameter, minimum diameter, and grain diameter of crystal grains forming the intermediate layer, the values ​​of the maximum diameter, minimum diameter, and grain diameter of crystal grains forming the wear-resistant layer, and the value of the ratio of the average grain diameter of crystal grains forming the wear-resistant layer to the average grain diameter of the crystal grains forming the intermediate layer (average grain diameter ratio) are shown in Table 2.

[0083] The grain diameter, maximum diameter, and minimum diameter of the crystal grains forming the intermediate layer and the wear-resistant layer can be measured as follows. The grain diameter of the crystal grains can be obtained by measuring the area of ​​each crystal grain and approximating the area to a circle. The grain diameter of the crystal grains can be obtained using, for example, the OIM analysis produced by TSL. Using the above-mentioned software, the crystal grains are approximated as ellipses and the major and minor axes of the ellipses are determined. The major and minor axes are defined as the maximum and minimum diameters of the crystal grains, and the average diameter of the maximum and minimum diameters can be calculated to obtain the average grain diameter of the crystal grain.

[0084] Similarly, on the cutting edge of a conventional coated tool as a comparison example, the maximum and minimum diameters of the crystal grains forming the intermediate layer and the maximum and minimum diameters of the crystal grains forming the wear-resistant layer were measured. Then, the grain diameters of the crystal grains forming the intermediate layer and the grain diameters of the crystal grains forming the wear-resistant layer were calculated. The ratio of the average grain diameter of the crystal grains forming the wear-resistant layer to the average grain diameter of the crystal grains forming the intermediate layer was calculated. The results are shown in Table 2.

[0085] For the manufactured samples No. 1 to No. 11, the maximum diameter, minimum diameter, and grain diameter of the crystal grains constituting the intermediate layer and the wear-resistant layer were measured, and the ratio of the average grain diameter of the crystal grains constituting the wear-resistant layer to the average grain diameter of the crystal grains constituting the intermediate layer was calculated. The grain diameter of the crystal grains was measured under the above conditions. The time required for the abrasion to reach 0.2 mm was measured from images obtained by capturing the abrasion wear of each sample after conducting a cutting test under the following conditions, and the time required for the abrasion wear amount to reach 0.2 mm was calculated. Table 2 Table 2 sample wear-resistant layer Intermediate layer Average particle size ratio Comparison of abrasion wear Sample No. Max. diameter (nm) Min. diameter (nm) Average grain size (nm) Max. diameter (nm) Min. diameter (nm) Average grain size (nm) Wear-resistant layer / intermediate layer (-) Duration (min) required until the abrasion wear amount reaches 0.2 mm 1 7,80 3,50 5,65 99,50 38,30 68,90 0,08 >34,6 2 10,00 4,80 7,40 99,50 38,30 68,90 0,11 >34,6 3 12,80 6,10 9,45 99,50 38,30 68,90 0,14 >34,6 4 26,50 13,30 19,90 99,50 38,30 68,90 0,29 >34,6 5 48,10 19,60 33,85 99,50 38,30 68,90 0,49 >34,6 6 59,10 33,80 46,45 99,50 38,30 68,90 0,67 >34,6 7 19,00 7,90 13,45 22,10 10,60 16,35 0,82 14,8 8 19,80 9,20 14,50 20,20 10,20 15,20 0,95 14,8 9 18,30 8,90 13,60 17,50 7,20 12,35 1,10 14,8 10 61,90 35,60 48,75 150,40 73,10 111,75 0,44 34,6 11 82,70 63,80 73,25 150,40 73,10 111,75 0,66 34,6

[0086] As shown in Table 2, it was confirmed that, for the coated tools according to the example, the ratio of the average grain diameter of the crystal grains forming the wear-resistant layer to the average grain diameter of the crystal grains forming the intermediate layer was 0.7 or less for both the cutting edge and the side surface of the coated tool. On the other hand, it was confirmed that the ratio of the average grain diameter of the crystal grains forming the wear-resistant layer to the average grain diameter of the crystal grains forming the intermediate layer was above 0.7 for the cutting edge of the coated tool according to the comparative example.

[0087] Cutting tests were conducted on the coated tool according to the example and the coated tool according to the comparative example. The cutting test conditions are as follows. Cutting test conditions Workpiece: Inconel (trade name) 718 Cutting speed (Vc): 30 m / min Feed (f): 0.10 mm / revolution Cut (ap): 0.5 mm Cutting condition: Wet Tool used: CNMG120408SG

[0088] Subsequently, based on an image showing the cutting edge condition of the coated tool according to Example after the cutting test, the length of abrasion wear in the thickness direction of the coating layer of the coated tool according to Example (hereinafter referred to as "abrasion wear amount") was measured. The cutting times in the cutting tests were 7.4 minutes, 14.8 minutes, 19.8 minutes, 24.7 minutes, 29.7 minutes, and 34.6 minutes.

[0089] Similarly, the abrasive wear amount in the thickness direction of the coating layer of the coated tool according to the comparative example shown in Sample No. 8 was measured using an image showing the cutting edge condition of the coated tool according to the comparative example after the cutting test. The cutting times in the cutting tests were 7.4 minutes and 14.8 minutes.

[0090] Fig. Figure 6 is a graph showing the correlation between cutting time and abrasion wear amount. The horizontal axis of the Fig. 6 shows the cutting time (minutes). The vertical axis of the graph in Fig. The diagram shown in Figure 6 represents the abrasion wear (mm). In the diagram shown in Fig. In the diagram shown in Figure 6, the white circles indicate the measured values ​​for the coated tool according to the example. The black circles indicate the measured values ​​for the coated tool according to the comparative example.

[0091] As in Fig. As shown in Figure 6, it was confirmed that the abrasion wear amount of the coated tool according to the example at a certain cutting time was smaller than the abrasion wear amount of the coated tool according to the comparative example shown in Sample No. 8. In other words, it was confirmed that at a certain abrasion wear amount, the cutting time of the coated tool according to the example was longer than the cutting time of the coated tool according to the comparative example shown in Sample No. 8.

[0092] Thus, it was confirmed that the wear resistance of the coated tool can be improved when the ratio between the average grain diameter of the crystal grains forming the wear-resistant layer and the average grain diameter of the crystal grains forming the intermediate layer is 0.7 or less. In other words, it was confirmed that the tool life of the coated tool can be extended.

[0093] The cutting edge condition of the coated tool after a cutting time of 7.4 minutes under the above-mentioned cutting conditions is shown in Fig. 7 and Fig. 8 shown. Fig. 7 is a picture showing the cutting edge state of the coated tool according to the example after a cutting test. Fig. Figure 8 is a picture showing the cutting edge condition of the coated tool according to the comparative example after a cutting test. In each of the Fig.7 and Fig. 8, the cutting edge section of the coated tool where the coating layer was scraped off by abrasive wear D3 and the base body was exposed is marked by a dashed white circle.

[0094] As in Fig. 7 and Fig. As shown in Figure 8, it was confirmed that the abrasion wear D3 in the coated tool according to the example was reduced compared to the abrasion wear D3 in the coated tool according to the comparative example shown in Sample No. 8. From these results, it was confirmed that the wear resistance of the coated tool can be improved when the ratio of the average grain diameter of crystal grains constituting the wear-resistant layer to the average grain diameter of the crystal grains constituting the intermediate layer is 0.7 or less. Supplementary NoteSupplementary Note 1

[0095] A coated tool comprising: a basic body; and a coating layer arranged on the base body, wherein the coating layer comprises an intermediate layer and a wear-resistant layer arranged on the intermediate layer, and a ratio of an average grain diameter of crystal grains forming the wear-resistant layer to an average grain diameter of the crystal grains forming the intermediate layer is 0.7 or less. Supplementary Note 2

[0096] The coated tool according to Supplementary Note 1, in which the average grain diameter of the crystal grains forming the intermediate layer is 100 nm or less, and the average grain diameter of the crystal grains forming the wear-resistant layer is 70 nm or less. Supplementary Note 3

[0097] The coated tool according to supplementary note 2, in which the average grain diameter of the crystal grains forming the intermediate layer is 70 nm or less and the average grain diameter of the crystal grains forming the wear-resistant layer is 50 nm or less. Supplementary Note 4

[0098] The coated tool according to any one of supplementary notes 1 to 3, wherein the coating layer further comprises an adhesion layer in contact with the base body. Supplementary Note 5

[0099] The coated tool according to Supplementary Note 4, in which the intermediate layer, the wear-resistant layer and the adhesion layer all contain Ti and Al as main components. Supplementary Note 6

[0100] The coated tool according to one of the supplementary notes 1 to 5, where the base body has a first surface that acts as a rake surface, a second area that acts as an open space, and a ridge line where the first surface and the second surface intersect, the coating layer has a first layer arranged at the ridge line, a second layer disposed on the first surface, and a third layer arranged on the second surface, and the ratio in the first layer is greater than the ratio in the second layer and the third layer. Supplementary Note 7

[0101] The coated tool according to Supplementary Note 6, in which the ratio in the second layer is greater than the ratio in the third layer. Supplementary Note 8

[0102] The coated tool according to Supplementary Note 6, in which the ratio in the third layer is greater than the ratio in the second layer. Supplementary Note 9

[0103] The coated tool according to any one of Supplementary Notes 6 to 8, wherein the average grain diameter of the crystal grains forming the wear-resistant layer in the first layer is larger than the average grain diameter of the crystal grains forming the wear-resistant layer in the second layer and the third layer. Supplementary Note 10

[0104] The coated tool according to any one of Supplementary Notes 6 to 9, wherein the average grain diameter of the crystal grains forming the intermediate layer in the first layer is larger than the average grain diameter of the crystal grains forming the intermediate layer in the second layer and the third layer. Supplementary Note 11

[0105] A cutting tool having: a holder having a rod shape, the holder having a pocket at an end portion of the holder; and the coated tool according to any one of supplementary notes 1 to 10, wherein the coated tool is arranged in the pocket.

[0106] Further effects and / or variations can be readily devised by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the general inventive concepts defined by the appended claims and their equivalents. REFERENCE SYMBOL 1 Coated tool 2 lace bodies 5 through hole 10 basic bodies 20 coating layers 21 Adhesive layer 22 Intermediate layer 23 wear-resistant layer 70 holders 73 Bag 75 screw 100 cutting tools 201 corner section D1 Primary edge wear D2 Secondary edge wear D3 Abrasion wear D4 Crater wear QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2016 / 017790

[0003]

Claims

[1] A coated tool comprising: a basic body and a coating layer arranged on the base body, wherein the coating layer has an intermediate layer and a wear-resistant layer arranged on the intermediate layer, and a ratio of an average grain diameter of crystal grains forming the wear-resistant layer to an average grain diameter of crystal grains forming the intermediate layer is 0.7 or less. [2] The coated tool according to claim 1, wherein the average grain diameter of the crystal grains forming the intermediate layer is 100 nm or less, and the average grain diameter of the crystal grains forming the wear-resistant layer is 70 nm or less. [3] The coated tool according to claim 2, wherein the average grain diameter of the crystal grains forming the intermediate layer is 70 nm or less and the average grain diameter of the crystal grains forming the wear-resistant layer is 50 nm or less. [4] The coated tool according to any one of claims 1 to 3, wherein the coating layer further comprises an adhesion layer in contact with the base body. [5] The coated tool according to claim 4, wherein the intermediate layer, the wear-resistant layer and the adhesion layer all contain Ti and Al as main components. [6] The coated tool according to any one of claims 1 to 5, wherein The base body has a first surface acting as a rake surface, a second area that acts as an open space, and a ridge line where the first surface and the second surface intersect, the coating layer has a first layer arranged at the ridge line, a second layer disposed on the first surface, and a third layer arranged on the second surface, and the ratio in the first layer is greater than the ratio in the second layer and the third layer. [7] The coated tool according to claim 6, wherein the ratio in the second layer is greater than the ratio in the third layer. [8] The coated tool according to claim 6, wherein the ratio in the third layer is greater than the ratio in the second layer. [9] The coated tool according to any one of claims 6 to 8, wherein an average grain diameter of crystal grains forming the wear-resistant layer in the first layer is larger than an average grain diameter of crystal grains forming the wear-resistant layer in the second layer and the third layer. [10] The coated tool according to any one of claims 6 to 9, wherein an average grain diameter of crystal grains forming the intermediate layer in the first layer is larger than an average grain diameter of crystal grains forming the intermediate layer in the second layer and the third layer. [11] A cutting tool comprising: a rod-shaped holder, the holder having a pocket at an end portion of the holder; and the coated tool according to any one of claims 1 to 10, wherein the coated tool is arranged in the pocket.

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