Coated tool, cutting tool and manufacturing method for a machined product

Abstract

A coated tool (1) comprising: a base element (3) having a first surface (7), and a coating layer (5) arranged on the first surface (7), where the coating layer (5) a first layer (17) comprising a plurality of α-Al2O3 crystal particles (15), and a second layer (19) comprising a titanium component, being in contact with the first layer (17) and being arranged between the first layer (17) and the base element (3), and at least one of the α-Al2O3 crystal particles (15) is a differently oriented crystal particle (15a) which has at least two differently oriented regions (15aa, 15ab) with different orientations.

Description

TECHNICAL FIELD

[0001] The present embodiment relates to a coated tool for use in a cutting operation. BACKGROUND

[0002] As a cutting tool for use when performing a cutting operation of a workpiece such as metal, a surface-coated cutting tool (hereinafter simply referred to as a coated tool) is known, which is described, for example, in WO 2017 / 009928 A. The coated tool described in WO 2017 / 009928 A comprises a base material and a coating formed on the base material.

[0003] The coating comprises a plurality of α-Al2O3 crystal grains and exhibits a (001) orientation. The crystal boundaries of the plurality of crystal grains comprise coincident lattice (CSL) grain boundaries and ordinary grain boundaries. This means that the coating in the coated tool described in WO 2017 / 009928 A comprises a plurality of crystal grains that have different orientations relative to each other, and some of the grain boundaries of these crystal grains are CSL grain boundaries.

[0004] In the coated tool described in WO 2017 / 009928 A, the coating comprises a plurality of crystal grains that have different orientations from one another. However, each crystal grain has a single orientation. Therefore, when a cutting operation is performed using the coated tool described in WO 2017 / 009928 A, depending on the direction in which chips flow, some crystal grains are likely to be worn away, and the wear resistance of the overall coating may be reduced. Today, there is a need for a coated tool having a coating with improved wear resistance.

[0005] Furthermore, from WO 2017 / 061 058 A1, a coated tool is known, comprising: a base element having a first surface, and a coating layer arranged on the first surface, wherein the coating layer has a first layer comprising a plurality of α-Al2O3 crystal particles, and at least one of the α-Al2O3 crystal particles is a differently oriented crystal particle having regions of different orientation.

[0006] Further coated tools are known from WO 2017 / 037 797 A1, US 2017 / 0 008 092 A1 and US 2014 / 0 287 210 A1.

[0007] It is an object of the present invention to provide a coated tool for a cutting tool and a manufacturing method for a machined product with increased machining time. SUMMARY

[0008] The object is achieved by a coated tool having the features of claim 1. The object is further achieved by a cutting tool having the features of claim 10. The object is further achieved by a manufacturing method for a machined product having the features of claim 11. Further embodiments of the coated tool are described in the respective dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing a coated tool in one embodiment. Fig. 2 is a sectional view along the line AA in the coated tool used in the Fig. 1 is shown. Fig. 3 is an enlarged view near a coating layer in the coated tool used in the Fig. 2 is shown. Fig. Figure 4 is an enlarged view of an area B1 shown in the Fig. 3 is shown. Fig. 5 is a plan view showing a cutting tool in the embodiment. Fig. Figure 6 is an enlarged view of an area B2 shown in the Fig. 5 is shown. Fig. 7 is a schematic diagram showing a step in a manufacturing method for a machined product in the embodiment. Fig. 8 is a schematic diagram showing a step in a manufacturing method for a machined product in the embodiment. Fig. 9 is a schematic diagram showing a step in a manufacturing method for a machined product in the embodiment. EMBODIMENTS

[0009] A coated tool 1 in the embodiment will be described in detail below with reference to the drawings. For descriptive purposes, the following referenced drawings show, in a simplified form, only major elements necessary for describing the following embodiment. Therefore, the coated tool 1 may include any structural elements not shown in the referenced drawings. Dimensions of these elements in each of the drawings are not those that faithfully represent the dimensions of actual structural elements and dimensional relationships of these elements. Coated tool

[0010] The coated tool 1 of the embodiment comprises a base member 3 and a coating layer 5 as shown in the Fig. 1 and the like. In the example shown in the Fig. 2, the base element 3 has a first surface 7 (in the Fig. 2 an upper surface), a second surface 9 arranged on a side opposite to the first surface 7 (in the Fig. 2 a lower surface) and a third surface 11, which is located between the first surface 7 and the second surface 9 (in the Fig. 2 a side surface).

[0011] The coating layer 5 is arranged on at least the first surface 7 of the base element 3. In the base element 3, the coating layer 5 can be arranged only on the first surface 7 or on a surface other than the first surface 7. The coating layer 5 is in the example shown in the Fig. 2, is also arranged on the third surface 11 in addition to the first surface 7. The coating layer 5 is present for the purpose of improving the characteristics of the coated tool 1 during a cutting operation, such as wear resistance and chipping resistance.

[0012] A cutting edge 13 may be arranged on at least a portion of a ridge line at which surfaces corresponding to the first surface 7 and the third surface 11 of the base member 3 intersect in the coated tool 1. When the coated tool 1 is used to perform a cutting operation on a workpiece, the cutting operation may be performed by bringing the cutting edge 13 into contact with the workpiece.

[0013] In the example shown in the Fig. 1, the base element 3 has a square plate shape and the first surface 7 has a square plate shape. The second surface 9 is also a square. In the example shown in the Fig. 1, at least a part of the first surface 7 (for example, a region having a width of 2 mm from the ridge line where the first surface 7 and the third surface 11 intersect) is a rake face region, and at least a part of the third surface 3 (for example, a region having a width of 2 mm from the ridge line where the first surface 7 and the third surface 11 intersect) is a flank surface region. However, it is not problematic even if at least a part of the first surface 7 is a flank surface region and at least a part of the third surface 11 is a rake face region.

[0014] The shape of the base element 3 is not limited to a square plate shape. For example, the first surface 7 can have a triangular, square, pentagonal, hexagonal, or circular shape. Alternatively, the base element 3 is not limited to a columnar shape and can have a plate shape.

[0015] In the example shown in the Fig. As shown in Figure 4, the coating layer 5 includes a first layer 17 comprising a plurality of α-Al2O3 (α-alumina) crystal particles 15. The first layer 17 contains α-Al2O3 as a main component, but may contain a component other than α-Al2O3. For example, the first layer 17 may contain a metal component such as Ti, Si, Nb, Hf, V, Ta, Mo, Zr, Cr, and W.

[0016] Aluminum oxide, such as γ-Al2O3 (γ-aluminum oxide) and κ-Al2O3 (κ-aluminum oxide), may be present. The term "main component" refers to a component that has the highest mass percentage among the other components.

[0017] An elemental analysis of the components contained in the first layer 17 can be evaluated, for example, by an energy dispersive X-ray spectrometer (SEM-EDX) attached to a scanning electron microscope (SEM) or by a method using an electron beam microanalysis device (EPMA).

[0018] Identification of the aluminum oxide among α-Al2O3, γ-Al2O3 and κ-Al2O3 contained in the first layer 17 can be carried out, for example, by performing an X-ray diffraction (XRD) analysis and by comparing it with the JCPDS table.

[0019] At least one of the α-Al2O3 crystal particles 15 in the example shown in the Fig. 4, a crystal particle 15a with a different orientation is one that has at least two differently oriented regions 15aa and 15ab (hereinafter referred to simply as regions) that have different orientations. That is, for example, when two of the α-Al2O3 crystal particles 15 are defined as a first crystal particle and a second crystal particle, the orientation of the first crystal particle and the orientation of the second crystal particle are not simply different from each other.

[0020] To facilitate visual understanding, the differently oriented crystal particle 15a among the plurality of α-Al2O3 crystal particles 15 having the at least two regions 15aa and 15ab having different orientations is shown in the Fig. 4 shown in gray.

[0021] When the differently oriented crystal particle 15a has at least two regions 15aa and 15ab that have different orientations, the wear resistance of the coating layer 5 is high. The reason for this is as follows.

[0022] As chips flow across the rake face area during a cutting operation of a workpiece, the chips come into contact with a portion of the coating layer 5 corresponding to the rake face area. Even if the orientations of the α-Al2O3 crystal particles 15 are the same, depending on the direction in which the chips flow, there is a case where the α-Al2O3 crystal particles 15 are likely to be worn away and a case where the α-Al2O3 crystal particles 15 are less likely to be worn away.

[0023] When each of the α-Al2O3 crystal particles 15 has only a single orientation, some of the crystal particles 15 are likely to wear, and the coating layer 5 as a whole is likely to wear with these crystal particles 15 as a starting point. However, since the two regions 15aa and 15ab have different orientations, even if one of the two regions 15aa is likely to be easily worn, the other 15ab of the two regions is less likely to be worn. Therefore, the overall wear resistance of the differently oriented crystal particles 15a is high.

[0024] Therefore, when at least one of the plurality of α-Al2O3 crystal particles 15 is the differently oriented crystal particle 15a having at least the two regions 15aa and 15ab with different orientations, the wear resistance of the coating layer 5 as a whole is high.

[0025] The first layer 17 may include at least one differently oriented crystal particle 15a. However, if the first layer 17 includes a plurality of differently oriented crystal particles 15a, the wear resistance of the first layer 17 is greater. It is not problematic even if at least one of the differently oriented crystal particles 15a has three or more regions. If a differently oriented crystal particle 15a has three or more regions, the overall wear resistance of the differently oriented crystal particles 15a is even greater.

[0026] The orientation of the α-Al2O3 crystal particles 15 can be evaluated by performing an orientation analysis of the α-Al2O3 crystal particles 15 using electron backscatter diffraction (EBSD). In an image obtained by EBSD, adjusting the coloring makes it possible to show the α-Al2O3 crystal particles 15 in different colors according to their orientation, and, for example, to show the space between neighboring crystal particles 15 in black.

[0027] By adjusting the coloring as described above, it is possible to easily detect boundaries between the plurality of α-Al2O3 crystal particles 15 contained in the first layer 17. Since the color of the α-Al2O3 crystal particles 15 is displayed according to the different orientation, it is possible to easily evaluate whether each of the α-Al2O3 crystal particles 15 has only one orientation or has two or more regions that have different orientations from each other.

[0028] The crystal particles 15 have in the example shown in the Fig. 4, as described above, α-Al2O3 has a crystal structure of a hexagonal crystal lattice, which is a hexagonal system. That is, in the α-Al2O3 crystal particles 15, the α-Al2O3 crystal generally has a hexagonal columnar shape. The surface corresponding to the end face of the hexagon in the hexagonal column is a (001) face in the α-Al2O3 crystal. Therefore, the α-Al2O3 crystal has a shape extending in a direction orthogonal to the (001) face.

[0029] In the hexagonal α-Al2O3 crystal particle 15, θ1 is an angle formed by the normal direction of the (001) face and the thickness direction of the first layer 17, θ2 is an angle formed by the normal direction of a (210) face and the thickness direction of the first layer 17, and θ3 is an angle formed by the normal direction of a (120) face and the thickness direction of the first layer 17. For example, when the normal direction of the (001) face and the thickness direction of the first layer 17 are the same, (θ1, θ2, θ3) = (0°, 90°, 90°) is considered true.

[0030] The values of (θ1, θ2, θ3) can be evaluated by an orientation analysis of the α-Al2O3 crystal particles 15 in the image obtained using electron backscatter diffraction. The values of (θ1, θ2, θ3) can be calculated, for example, by comparing the normal direction components of each of the (001) face, the (210) face, and the (120) face.

[0031] If the orientation of the two regions 15aa and 15ab are different from each other, the values of (θ1, θ2, θ3) in one 15aa of the two regions are different from the values of (θ1, θ2, θ3) in the other 15ab of the two regions.

[0032] The values (θ1, θ2, θ3) in each of the two regions 15aa and 15ab are not limited to specific values. For example, in each of the two regions 15aa and 15ab, θ1 may be smaller than θ2 and θ3.

[0033] When θ1 is smaller than θ2 and θ3 in each of the two regions 15aa and 15ab, the Al2O3 crystal is less likely to have a shape that is relatively extended in the thickness direction of the first layer 17. Therefore, each of the two regions 15aa and 15ab has high wear resistance. The orientations of the two regions 15aa and 15ab are indicated, for example, by (001), (104), (105), or (018) when θ1 is smaller than θ2 and θ3. However, it goes without saying that the orientations of the two regions 15aa and 15ab are not limited to this.

[0034] In at least one of the differently oriented crystal particles 15a, which are shown in a cross-section orthogonal to the first surface 7, the boundary between the regions 15aa and 15ab may extend along the thickness direction of the first layer 17. In the example shown in the Fig. 4, the boundaries between the regions 15aa and 15ab are indicated by a two-dot dashed line.

[0035] When the above boundary extends along the thickness direction of the first layer 17, both of the two regions 15aa and 15ab are likely to come into contact with the workpiece when the differently oriented crystal particles 15a come into contact with the workpiece during a cutting process. As a result, the differently oriented crystal particles 15a are less likely to be worn, and therefore the overall wear resistance of the coating layer 5 is high.

[0036] The expression that “the boundary between the regions 15aa and 15ab extends along the thickness direction of the first layer 17” means that the angle formed by an imaginary straight line connecting one end of the side of the base member 3 and one end of the surface side in the above regions with respect to the thickness direction of the first layer 17 is equal to or less than 30°.

[0037] In at least one of the differently oriented crystal particles 15a having the two or more regions 15aa and 15ab, the boundary may extend over a portion of the differently oriented crystal particles 15a on the side remote from the base member 3. In this case, the wear resistance of the first layer 17 is further increased. Therefore, in the above case, both of the two regions 15aa and 15ab are likely to come into contact with the workpiece when the differently oriented crystal particles 15a come into contact with the workpiece during the cutting process.

[0038] The expression that “the part of the differently oriented crystal particle 15a on the side far from the base member 3” means a part which is located on a side farther from the base member 3 than the center of the differently oriented crystal particle 15a in a direction along the thickness direction.

[0039] The boundary between the regions 15aa and 15ab may extend over a portion on a side farthest from the base member 3 among the differently oriented crystal particles 15a divided into four equal parts along the thickness direction. In this case, both of the two regions 15aa and 15ab are more likely to come into contact with the workpiece when the differently oriented crystal particles 15a come into contact with the workpiece during a cutting operation.

[0040] The first layer 17, which is in the Fig. 4, has a first surface 17A facing the base member 3 and a surface 17B located on an opposite side of the surface 17A. At least one of the differently oriented crystal particles 15a may be arranged from the surface 17A to the surface 17B. When the differently oriented crystal particles 15a are arranged as described above, the durability of the first layer 17 is high over a wide range in the thickness direction. Therefore, the wear resistance of the first layer 17 is high even when a cutting operation is performed for a long period of time.

[0041] The Fig. The first layer 17 shown in Figure 4 includes the plurality of differently oriented crystal particles 15a. The first layer 17 may include a portion where at least two of the plurality of differently oriented crystal particles 15a are adjacent to each other. When at least two of the differently oriented crystal particles 15a, which have excellent wear resistance, are adjacent to each other, the wear resistance of the first layer 17 is excellent.

[0042] Specifically, for example, at least two of the plurality of differently oriented crystal particles 15a may be adjacent to each other along the thickness direction of the first layer 17. Even if the differently oriented crystal particle 15a on the side farthest from the base member 3 in the thickness direction of the first layer 17 of the above-described two differently oriented crystal particles 15a is worn due to a long-term cutting process, the wear resistance of the first layer 17 is maintained by the differently oriented crystal particle 15a on the side closest to the base member 3 in the thickness direction of the first layer 17 of the above-described two differently oriented crystal particles 15a. Therefore, the durability of the first layer 17 is high even for a long-term cutting process.

[0043] For example, at least two of the plurality of differently oriented crystal particles 15a may be adjacent to each other along the direction orthogonal to the thickness direction of the first layer 17. In this case, both of these two differently oriented crystal particles 15a are likely to come into contact with the workpiece simultaneously during the cutting process. Therefore, the durability of the first layer 17 is high when these two differently oriented crystal particles 15a are in contact with the workpiece.

[0044] In the cross section orthogonal to the first surface 7, among the plurality of α-Al2O3 crystal particles 15, an average particle diameter of the differently oriented crystal particles 15a having the region 15aa and 15ab may be larger than an average particle diameter of the crystal particle 15 other than the differently oriented crystal particle 15a. Also, in this case, the wear resistance of the first layer 17 is high. Therefore, in the differently oriented crystal particle 15a including one region, the volume occupied by each region is likely to be small compared to the crystal particle 15 having only one orientation different from the differently oriented crystal particle 15a. However, in the above case, it is easy to ensure the volume occupied by each region.

[0045] Among the plurality of α-Al2O3 crystal particles 15, an average width in the direction orthogonal to the thickness direction of the first layer 17 in the differently oriented crystal particles 15a having the two regions 15aa and 15ab as regions may be larger than an average width in the direction orthogonal to the thickness direction of the first layer 17 in the crystal particles 15 other than the differently oriented crystal particles 15a. In this case, the wear resistance of the first layer 17 is high.

[0046] In the cross-section orthogonal to the first surface 7, a boundary between the two regions 15aa and 15ab in one of the plurality of differently oriented crystal particles 15a may be a Σ3-type crystal grain boundary. In this case, the bonding ability between the two regions 15aa and 15ab is high. Therefore, the strength of these differently oriented crystal particles 15a is high.

[0047] The expression "the boundary between the two regions 15aa and 15ab is a Σ3-type crystal grain boundary" means that the entire boundary is not limited to a Σ3-type crystal grain boundary. This boundary may, for example, partially include a Σ7-type crystal grain boundary, a Σ11-type crystal grain boundary, a Σ17-type crystal grain boundary, a Σ19-type crystal grain boundary, a Σ21-type crystal grain boundary, a Σ23-type crystal grain boundary, or a Σ29-type crystal grain boundary. However, even if the boundary partially includes these crystal grain boundaries, the length of the Σ3-type crystal grain boundary is greater than the sum of the lengths of these crystal grain boundaries in the cross-section orthogonal to the first surface 7.

[0048] The coating layer 5 can be configured to comprise only the first layer 17, or can comprise a further layer in addition to the first layer 17. The coating layer 5 can, for example, comprise, in addition to the first layer 17, a second layer 19 arranged between the first layer 17 and the base element 3, and a third layer 21 arranged on the first layer 17, as shown in the Fig. 3 is shown.

[0049] The second layer 19 is arranged between the first layer 17 and the base member 3, is in contact with the first layer 17 and the base member 3 and has a titanium component in the example shown in the Fig. 3. Examples of the titanium component contained in the second layer 19 include carbides, nitrides, oxides, carbonitrides, carbon oxides, and oxycarbonitrides. The second layer 19 may be configured to contain only one of the above components, or may alternatively be configured to contain a plurality of the above components.

[0050] The second layer 19 may be formed as a single layer, or alternatively, it may have a configuration in which a plurality of layers are laminated together. For example, the second layer 19 may have a configuration in which a layer 19a, which is disposed on the side of the base member 3 and contains titanium nitride (TiN), and a layer 19b, which is disposed on a side of the first layer 17 and contains titanium carbonitride (TiCN), are arranged in sequence.

[0051] In a case where the second layer 19 includes the layer containing titanium nitride, the bondability between the base member 3 and the coating layer 5 is improved. In a case where the second layer 19 includes the layer containing titanium carbonitride, the bondability between the first layer 17 and the second layer 19 is high.

[0052] The third layer 21 is arranged on the first layer 17 in contact with it and has a titanium component in the example which is shown in the Fig. 3. Examples of the titanium component contained in the third layer 21 include titanium carbide, nitride, oxide, carbonitride, carbon oxide, and oxycarbonitride, as in the second layer 19.

[0053] An elemental analysis of the components contained in each of the second layer 19 and the third layer 21 can be evaluated similarly to the elemental analysis in the first layer 17, for example, by SEM-EDX or a method using EPMA.

[0054] In the coated tool 1 of this embodiment, since at least one of the plurality of α-Al2O3 crystal particles 15 is a differently oriented crystal particle 15a having at least the two regions 15aa and 15ab with different orientation, the wear of the first layer 17 is less likely to progress in the differently oriented crystal particle 15a having the two regions 15aa and 15ab even in a case where the third layer 21 is worn and the first layer 17 is exposed.

[0055] The second layer 19 and the third layer 21 may contain a component other than titanium. For example, if the second layer 19 and the third layer 21 contain aluminum oxide, the bonding ability among the first layer 17, the second layer 19, and the third layer 21 is high. Since the second layer 19 and the third layer 21 contain a titanium component, the bonding ability among the first layer 17, the second layer 19, and the third layer 21 is high even in a case where the first layer 17 contains titanium.

[0056] Examples of the material of the base member 3 include inorganic materials such as cemented carbide, cermet, and ceramics. The material of the base member is not limited to these materials.

[0057] Examples of cemented carbide compositions include WC-(tungsten carbide)-Co, WC-TiC-(titanium carbide)-Co, and WC-TiC-TaC-(tantalum carbide)-Co. Specifically, WC, TiC, and TaC are hard particles, and Co is a binder phase. Cermet is a sintered composite material obtained by combining metal and a ceramic component. Specific examples of cermets include compounds composed primarily of TiCN, TiC, or TiN.

[0058] The base element 3 may have a through-hole 23 extending through the first surface 7 and the second surface 9. The through-hole 23 is usable for receiving a fixing element intended to fix the coated tool 1 to the holder. Examples of the fixing element include a screw and a clamping element.

[0059] The size of the base element 3 is not particularly limited. For example, a length of one side of the first surface 7 can be set to approximately 3 to 20 mm. A height from the first surface 7 to the second surface 9 can be set to approximately 2 to 20 mm. Manufacturing process

[0060] A method for manufacturing the coated tool 1 in the embodiment is described below.

[0061] First, a powder mixture is prepared by appropriately adding metal powder, carbon powder or the like to an inorganic powder selected from carbide, nitride, carbonitride and oxide or the like capable of forming a hard alloy by sintering, which constitutes the base member 3, and then mixing them together.

[0062] Subsequently, a molded body is produced by molding the powder mixture into a predetermined mold shape using a known molding method. Examples of the molding method include compression molding, casting molding, extrusion molding, and cold isostatic pressing. The base member 3 is produced by sintering the molded body in a vacuum or a non-oxidizing atmosphere. A surface of the base member may then be subjected to polishing and honing, if necessary.

[0063] Subsequently, the coating layer 5 is deposited on the surface of the base element 3 by a chemical vapor deposition (CVD) process.

[0064] The first layer 17 can be formed by the following method. A first gas mixture is prepared by mixing 5 to 15 vol% of aluminum trichloride (AlCl3) gas, 0.5 to 2.5 vol% of hydrogen chloride (HCl) gas, 0.5 to 10 vol% of carbon dioxide (CO2) gas, and equal to or less than 1 vol% of hydrogen sulfide (H2S) gas in hydrogen (H2) gas. This first gas mixture is introduced into the chamber under conditions of a deposition temperature of 950 to 1100°C and a gas pressure of 5 to 20 kPa. In this way, the first layer 17 can be formed in the coating layer 5.

[0065] Not by forming the first layer 17 in a state in which the proportion of carbon dioxide gas in the first gas mixture is constant but by changing the proportion of carbon dioxide gas in the middle of forming the first layer 17, it is possible to form the differently oriented crystal particle 15a having the at least two regions 15aa and 15ab having different orientations.

[0066] It is possible to form the differently oriented crystal particle 15a having the two regions 15aa and 15ab having different orientations from each other by reducing the proportion of the carbon dioxide gas in a middle of forming the first layer 17 so that in the initial stage of forming the first layer 17, the proportion of the carbon dioxide gas is larger than that of the aluminum trichloride gas, and in a later stage of forming the first layer 17, the proportion of the aluminum trichloride gas is larger than that of the carbon dioxide gas.

[0067] When the coating layer 5 has the second layer 19 disposed between the base member 3 and the first layer 17, the second layer 19 can be formed by the following method.

[0068] First, a second gas mixture is prepared by mixing 0.5 to 10 vol% titanium tetrachloride gas and 10 to 60 vol% nitrogen (N2) gas in hydrogen gas. This second gas mixture is introduced into the chamber under conditions of a deposition temperature of 800 to 940°C and a gas pressure of 8 to 50 kPa. In this way, the layer 19a containing titanium nitride can be formed in the second layer 19.

[0069] A third gas mixture is prepared by mixing 0.5 to 10 vol% titanium tetrachloride gas, 5 to 60 vol% nitrogen gas, and 0.1 to 3 vol% acetonitrile (CH3CN) gas in hydrogen gas. This third gas mixture is introduced into the chamber under conditions of a deposition temperature of 780 to 880°C and a gas pressure of 5 to 25 kPa. In this way, the layer 19b containing titanium carbonitride can be formed in layer 19.

[0070] When the coating layer 5 includes the third layer 21 disposed on the first layer 17, the third layer 21 can be formed by the following method. A fourth gas mixture is prepared by mixing 0.1 to 10 vol% titanium tetrachloride (TiCl4) gas and 10 to 60 vol% nitrogen gas in hydrogen gas. This fourth gas mixture is introduced into the chamber under conditions of a deposition temperature of 960 to 1100°C and a gas pressure of 10 to 85 kPa. In this way, the third layer 21 can be formed in the coating layer 5.

[0071] Subsequently, if necessary, a polishing process is performed on a portion of the surface of the deposited coating layer 5 where the cutting edge 13 is located. When the polishing process is performed, a workpiece is less likely to weld to the cutting edge 13, resulting in the coated tool 1 having excellent fracture resistance.

[0072] The above manufacturing method is an example of the method for manufacturing the coated tool 1 of the present embodiment. Therefore, the coated tools 1 are not limited to those manufactured by the above manufacturing method. Cutting tool

[0073] A cutting tool 101 of the embodiment will be described below with reference to the drawings.

[0074] As it is in the Fig. 5 and Fig. 6, the cutting tool 101 of the embodiment has a rod-shaped body extending from a first end (an upper end in the Fig. 5) extends to a second end (a lower end in the Fig. 5). The cutting tool 101 includes a holder 105 having a pocket 103 at one side of the first end, and the coated tool 1 disposed in the pocket 103. In the cutting tool 101 of the embodiments, the coated tool 1 is fixed so that a portion of the ridge line usable as a cutting edge in the cutting tool 101 of the embodiment protrudes from a front end of the holder 105.

[0075] The pocket 103 is a part that allows the coated tool 1 to be secured. The pocket 103 has a seating surface parallel to a lower surface of the holder 105 and a retaining side surface that is inclined relative to the seating surface. The pocket 103 is open in one side of the first end of the holder 105.

[0076] The coated tool 1 is arranged in the pocket 103. A surface on the opposite side of the first surface in the coated tool 1 can be in direct contact with the pocket 103. Alternatively, a plate can be held between the coated tool 1 and the pocket 103.

[0077] The coated tool 1 is fixed so that the part of the ridge line usable as the cutting edge protrudes outward from the holder 105. In the embodiment, the coated tool 1 is fixed to the holder 105 by a screw 107. Specifically, the coated tool 1 is fixed to the holder 105 in such a manner that screw parts are engaged with each other by inserting the screw 107 into the through hole of the coated tool 1 and by inserting a front end of the screw 107 into a screw hole (not shown) formed in the pocket 103.

[0078] For example, steel and cast iron can be used as the holder 105. Of these elements, high-toughness steel is preferred.

[0079] The embodiment has described and illustrated cutting tools for use in a so-called turning process. Examples of the turning process include inner diameter machining, outer diameter machining, and grooving machining. The cutting tools are not limited to those used in the turning process. For example, the coated tools 1 of the above embodiments are applicable to cutting tools for use in the milling process. Manufacturing process for a machined product

[0080] A manufacturing method for a machined product in the embodiment will be described below with reference to the drawings.

[0081] The machined product can be manufactured by performing a cutting process of a workpiece 201. The method for manufacturing a machined product in the embodiment comprises the following steps: (1) Rotating the workpiece 201, (2) Bringing the cutting tool 101 represented by the above embodiment into contact with the workpiece 201 which is rotated, and (3) Moving the cutting tool 101 away from the workpiece 201.

[0082] In particular, the workpiece 201 is first rotated about an axis O1 and then the cutting tool 101 is brought relatively close to the workpiece 201, as shown in the Fig. 7. Then, the workpiece 201 is cut by bringing the cutting edge in the cutting tool 101 into contact with the workpiece 201, as shown in the Fig. 8. Thereafter, the cutting tool 101 is moved relatively away from the workpiece 201, as shown in the Fig. 9 is shown.

[0083] In the example, the cutting tool 101 is brought close to the workpiece 201 by fixing the axis O1 and moving the cutting tool 101 in a Y1 direction in a state in which the workpiece 201 is rotated around the axis O1. Fig. 8, the workpiece 201 is cut by bringing the cutting edge in an insert 1 into contact with the workpiece 201, which is rotated. In the Fig. 9, the cutting tool 101 is moved away by moving in the Y2 direction in a state in which the workpiece 201 is rotated.

[0084] During the cutting process in the manufacturing method of the embodiment, the cutting tool 101 is brought into contact with the workpiece 201 or the cutting tool 101 is moved away from the workpiece 201 by moving the cutting tool 101 in each of the steps. However, it is not intended to be limited to the above embodiment.

[0085] For example, in step (1), the workpiece 201 may be brought close to the cutting tool 101. Similarly, in step (3), the workpiece 201 may be moved away from the cutting tool 101. As the cutting process continues, it is necessary to repeat the step of bringing the cutting edge of the insert 1 into contact with various portions of the workpiece 201 while continuing to rotate the workpiece 201.

[0086] Representative examples of the material of the workpiece 201 include unalloyed steel, alloy steel, stainless steel, cast iron, and non-ferrous metals. LIST OF REFERENCE SYMBOLS 1 coated tool 3 Basic element 5 coating layer 7 first area 9 second area 11 third area 13 Cutting edge 15 crystal particles 15a differently oriented crystal particles 15aa differently oriented areas 15ab differently oriented areas 17 first layer 17A first area 17B Surface opposite to the first surface19: second layer 19a Layer on the side of the base element 19b Layer on one side of the first layer 21 third layer 23 through hole 101 Cutting tools 103 Bag 105 holders 107 Screw 201 Workpiece O1 rotation axis Y1 Direction of movement Y2 Direction of movement

Claims

[1] A coated tool (1) comprising: a base element (3) having a first surface (7), and a coating layer (5) arranged on the first surface (7), where the coating layer (5) a first layer (17) comprising a plurality of α-Al2O3 crystal particles (15), and a second layer (19) comprising a titanium component, being in contact with the first layer (17) and being arranged between the first layer (17) and the base element (3), and at least one of the α-Al2O3 crystal particles (15) is a differently oriented crystal particle (15a) which has at least two differently oriented regions (15aa, 15ab) with different orientations. [2] The coated tool (1) according to claim 1, wherein at least one of the differently oriented crystal particles (15a) has three or more differently oriented regions. [3] The coated tool (1) according to claim 1, wherein a boundary between the differently oriented regions (15aa, 15ab) extends along a thickness direction of the first layer (17) in at least one of the differently oriented crystal particles (15a). [4] The coated tool (1) according to claim 3, wherein the first layer (17) has a surface A facing the base element (3), and a surface B arranged on an opposite side of surface A, and at least one of the differently oriented crystal particles (15a) is arranged from surface A to surface B. [5] The coated tool (1) according to any one of claims 1 to 4, wherein the first layer (17) has a part in which a plurality of differently oriented crystal particles (15a) are adjacent to each other. [6] The coated tool (1) according to claim 5, wherein the plurality of differently oriented crystal particles (15a) are adjacent to each other along a thickness direction of the first layer (17). [7] The coated tool (1) according to claim 5 or 6, wherein the plurality of differently oriented crystal particles (15a) are adjacent to each other along a direction orthogonal to a thickness direction of the first layer (17). [8] The coated tool (1) according to any one of claims 1 to 7, wherein an average particle diameter of the differently oriented crystal particles (15a) is larger than an average particle diameter of the crystal particles other than the differently oriented crystal particles (15a). [9] The coated tool (1) according to any one of claims 1 to 8, wherein a boundary between the two differently oriented regions is a Σ3-type crystal grain boundary. [10] A cutting tool (101) comprising: a holder (105) having a pocket (103) arranged on one side of a front end, and the coated tool (1) according to any one of claims 1 to 9, which is arranged on the pocket (103). [11] A manufacturing method for a machined product, comprising: Rotating the cutting tool (101) according to claim 10, Bringing the cutting tool (101), which is rotated, into contact with a workpiece (201), and Moving the cutting tool (101) away from the workpiece (201).

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