Coated cutting tool and cutting tool

Abstract

An exemplary coated cutting tool of the present disclosure that is not limited has a substrate and a coating located on the substrate. The coated cutting tool has a first surface, a second surface adjacent to the first surface, and a cutting edge located at least in part on a ridge portion between the first surface and the second surface. The coating has an Al2O3 layer. When the fracture toughness value of the Al2O3 layer is measured on the surface of the coating parallel to the surface of the substrate, the fracture toughness value of the Al2O3 layer is 5 MPa·m 0.5 or more in a first region.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of Japanese Patent Application No. 2020 - 112955, filed on June 30, 2020, and incorporates the entire disclosure of the prior application herein by reference. Technical field

[0003] The present disclosure relates to a coated cutting tool and a cutting tool having the same. Background art

[0004] A coated cutting tool for a cutting tool or the like has a coating on a substrate. The coating is formed by CVD method or PVD method. As an example of a coating formed by CVD method, a coating in which a TiN layer, a TiCN layer, and an Al2O3 layer are sequentially laminated on a substrate can be cited.

[0005] The coating formed by CVD method sometimes has a large residual stress. In order to relieve the residual stress, a measure of projecting ceramic particles onto the coating is taken.

[0006] For example, Japanese Patent No. 4739235 (Patent Document 1) describes that sandblasting treatment based on ceramic abrasive grains is performed on the coating. Summary of the invention

[0007] A coated cutting tool according to an exemplary, non - limiting aspect of the present disclosure has a substrate and a coating on the substrate. The coated cutting tool includes a first face, a second face adjacent to the first face, and a cutting edge located at least in part on a ridge line portion between the first face and the second face. The coating has an Al2O3 layer. The Al2O3 layer has a fracture toughness value of 5 MPa·m when the fracture toughness value of the Al2O3 layer is measured on the surface of the coating parallel to the surface of the substrate 0.5 in the above - mentioned first region. Brief description of the drawings

[0008] Figure 1 is a perspective view showing a coated cutting tool according to an exemplary, non - limiting embodiment of the present disclosure.

[0009] Figure 2 is Figure 1 a cross - sectional view of the coated cutting tool shown in II - II.

[0010] Figure 3 is Figure 2 an enlarged view near the coating of the coated cutting tool shown.

[0011] Figure 4 is an electron microscope (SEM) photograph of spherical ceramic particles.

[0012] Figure 5 This is a scanning electron microscope (SEM) photograph of angular ceramic particles.

[0013] Figure 6 It is a perspective view showing a cutting tool according to a non-limiting embodiment of the present disclosure. DETAILED DESCRIPTION

[0014] <Coated tools>

[0015] Hereinafter, the coated tool 1 of the non-limited embodiment of the present disclosure will be described in detail using the accompanying drawings. However, in the following referenced figures, for the convenience of description, only the main components required in the description of the embodiment are simplified. Therefore, the coated tool 1 can have any components not shown in the referenced figures. In addition, the dimensions of the components in the figures do not accurately represent the dimensions of the actual components and the dimensional ratios of the components.

[0016] exist Figures 1 to 3 , as an example of the coated tool 1, a cutting insert that can be applied to a cutting tool is shown. In addition to the cutting tool, the coated tool 1 can also be applied to, for example, sliding parts, wear-resistant parts such as molds, tools such as excavators and blades, and impact-resistant parts. It should be noted that the use of the coated tool 1 is not limited to the illustrated content.

[0017] The coated tool 1 may also include a base body 2 and a coating 3 located on the base body 2 .

[0018] As the material of the substrate 2, for example, cemented carbide, ceramics and metals can be listed. As cemented carbide, for example, a superhard alloy formed by bonding a hard phase consisting of WC (tungsten carbide) and at least one of the carbides, nitrides and carbonitrides of the 4th, 5th and 6th group metals selected from the periodic table other than WC according to desire with a bonding phase consisting of ferrous metals such as Co (cobalt) and Ni (nickel) can be listed. In addition, as other cemented carbides, Ti-based metal ceramics can also be listed. As ceramics, for example, Si3N4 (silicon nitride), Al2O3 (aluminum oxide), diamond and cBN (cubic boron nitride) can be listed. As metal, for example, carbon steel, high-speed steel and alloy steel can be listed. It should be noted that the material of the substrate 2 is not limited to the exemplified material.

[0019] The coating layer 3 may cover the entire surface 4 of the substrate 2 or only a portion thereof. When the coating layer 3 covers only a portion of the surface 4 of the substrate 2 , it can be said that the coating layer 3 is located at least partially on the substrate 2 .

[0020] The coating layer 3 may also be formed by chemical vapor deposition (CVD). In other words, the coating layer 3 may also be a CVD film.

[0021] Coating 3 is not limited to a specific thickness. For example, the thickness of coating 3 can be set to 1 to 30 μm. It should be noted that the measurement of the thickness, structure, shape of the crystals constituting coating 3, etc. can be carried out, for example, by cross-sectional observation using an electron microscope. As the electron microscope, for example, a scanning electron microscope (SEM) and a transmission electron microscope (TEM) etc. can be cited.

[0022] As Figure 1 and Figure 2 In an unrestricted example shown as such, the coated cutting tool 1 may include: a first surface 5 (upper surface), a second surface 6 (side surface) adjacent to the first surface 5, and a cutting edge 7 located at at least a part of the ridge line portion between the first surface 5 and the second surface 6.

[0023] The first surface 5 may also be a rake face. The first surface 5 may be entirely a rake face, or alternatively, a part of it may be a rake face. For example, the region along the cutting edge 7 in the first surface 5 may also be a rake face.

[0024] The second surface 6 may also be a flank face. The second surface 6 may be entirely a flank face, or alternatively, a part of it may be a flank face. For example, the region along the cutting edge 7 in the second surface 6 may also be a flank face.

[0025] The cutting edge 7 may be located at a part of the ridge line portion, or alternatively, may be located at the entire ridge line portion. The cutting edge 7 can be used for cutting a workpiece to be cut.

[0026] As Figure 1 In an unrestricted example shown as such, the coated cutting tool 1 may also be in the shape of a quadrilateral plate. It should be noted that the shape of the coated cutting tool 1 is not limited to the quadrilateral plate shape. For example, the first surface 5 may also be triangular, pentagonal, hexagonal or circular. Additionally, the coated cutting tool 1 may also be in the shape of a cylinder.

[0027] The coated cutting tool 1 is not limited to a specific size. For example, the length of one side of the first surface 5 can be set to about 3 to 20 mm. Additionally, the height from the first surface 5 to the surface (lower surface) located on the opposite side of the first surface 5 can also be set to about 5 to 20 mm.

[0028] Here, as Figure 3 In an unrestricted example shown as such, coating 3 may also have an Al2O3 layer 8.

[0029] The Al2O3 layer 8 may also be a layer containing Al2O3 particles. Additionally, the Al2O3 layer 8 may also be a layer containing Al2O3 as the main component. The meaning of "main component" can mean the component with the largest mass% value compared to other components. These points can also be defined similarly in other layers.

[0030] The Al2O3 layer 8 may also have a first region. The first region may also have a fracture toughness value of 5 MPa·m 0.5 or more. This fracture toughness value may also be the value measured on the surface 9 of the coating 3 parallel to the surface 4 of the substrate 2 for the fracture toughness value of the Al2O3 layer 8.

[0031] The meaning of the above-mentioned "parallel" is not limited to strict parallelism, and it may also refer to an inclination allowing about ±10°. In addition, the fracture toughness value may also be measured by performing an indentation test on a mirror-finished surface using a nano-indentation instrument and observing cracks in the obtained indentation using a field emission scanning electron microscope (FE-SEM). In mirror polishing, a material in which diamond polishing paste with an average particle diameter of 1 to 3 μm manufactured by tomeidiamond Co., Ltd. and olive oil manufactured by Sankei Kogyo Co., Ltd. are adjusted so that the polishing paste concentration becomes 20 to 30% by mass may also be used. As the nano-indentation instrument, for example, an ultra-micro indentation hardness tester ENT-1100b / a manufactured by elionix Co., Ltd. may also be used for measurement. The indentation load is 700 (mN), and the indenter used in the measurement may also be a glass indenter ENT-20-13 manufactured by toyo-technica Co., Ltd. The fracture toughness value may also be measured based on JIS R 1607:2015. Observation of cracks may also be performed using JSM-7100F manufactured by JEOL Ltd.

[0032] When the Al2O3 layer 8 has the above-mentioned first region, the coating 3 is difficult to be damaged, and thus it is excellent in damage resistance. It should be noted that all of the Al2O3 layer 8 may be composed of the first region, and in addition, a part of the Al2O3 layer 8 may be composed of the first region. Hereinafter, the fracture toughness value of the first region is referred to as the first fracture toughness value. The upper limit value of the first fracture toughness value may also be 10 MPa·m 0.5 .

[0033] The Al2O3 layer 8 may also have first regions on the first surface 5 and the second surface 6, respectively. In this case, the first surface 5 and the second surface 6 are difficult to be damaged.

[0034] The Al2O3 layer 8 may also have a second region. The Al2O3 layer 8 in the coated cutting tool 1 does not need to have high fracture toughness in all regions. For example, the second region is arranged in a region not involved in cutting, or a region involved in cutting but not subjected to a large force or impact. It should be noted that the region not involved in cutting may also refer to a region separated by 1 mm or more from the cutting edge 7 in the directions of the first surface 5 and the second surface 6. The second region may also have a fracture toughness value less than 5 MPa·m 0.5This fracture toughness value can also be a value obtained when the fracture toughness value of the Al2O3 layer 8 is measured on the surface 9 of the coating 3 parallel to the surface 4 of the substrate 2.

[0035] The first region of the present disclosure is obtained, for example, by a sandblasting process using spherical ceramic powder having a specified hardness. In the sandblasting process, so-called dry sandblasting or wet sandblasting can also be used. Wet sandblasting has the advantage of being excellent in the processability of ceramic powder.

[0036] When the Al2O3 layer 8 has the above-mentioned first region and second region, the time of the sandblasting process can also be shortened, and the coated cutting tool 1 can be manufactured at low cost. Hereinafter, the fracture toughness value of the second region is referred to as the second fracture toughness value. It should be noted that the lower limit value of the second fracture toughness value can also be 0.3 MPa·m 0.5 。

[0037] When the hardness of the first region is the first hardness and the hardness of the second region is the second hardness, the second hardness can also be greater than the first hardness. In this case, the wear resistance of the coated cutting tool 1 is high.

[0038] The first hardness and the second hardness are not limited to specific values. For example, the first hardness can also be set to about 10 to 30 GPa. The second hardness can also be set to about 15 to 30 GPa. The first hardness and the second hardness can be measured, for example, by an indentation test using a nanoindenter in the same manner as the measurement of the fracture toughness value of the Al2O3 layer 8. As the nanoindenter, for example, the ultra-micro indentation hardness tester ENT-1100b / a manufactured by Elionix, Inc. can also be used for measurement. The indentation load is 700 (mN), and the indenter used in the measurement can also be the glass indenter ENT-20-13 manufactured by Toyo-Technica Co., Ltd.

[0039] The Al2O3 layer 8 can also have a first region on the first surface 5, and in addition, can have a second region on the second surface 6. In this case, the wear resistance and chipping resistance of the coated cutting tool 1 are high.

[0040] The coating 3 can also have a Ti-based coating 10 between the substrate 2 and the Al2O3 layer 8. The Ti-based coating 10 can also be a layer containing TiCN particles, TiC particles, or TiN particles. In addition, the Ti-based coating 10 can also be a layer containing TiCN as a main component.

[0041] The Ti-based coating 10 can also have a third region. The third region can also be a region having a fracture toughness value of 10 MPa·m 0.5This fracture toughness value may be a value obtained by measuring the fracture toughness value of the Ti-based coating 10 at the surface 9 of the coating 3 parallel to the surface 4 of the substrate 2 .

[0042] When the Ti-based coating 10 has the third region, the coating 3 is difficult to be damaged, and thus has excellent damage resistance. It should be noted that the Ti-based coating 10 may be entirely composed of the third region, or a portion of the Ti-based coating 10 may be composed of the third region. Hereinafter, the fracture toughness value of the third region is referred to as the third fracture toughness value. The upper limit of the third fracture toughness value may also be 20 MPa·m 0.5 .

[0043] The Ti-based coating 10 may also have a fourth region. The Ti-based coating 10 of the coated tool 1 does not need to have high fracture toughness in all regions. For example, the fourth region may be configured in an area not involved in cutting, or in an area involved in cutting but not subject to large force or impact. It should be noted that the area not involved in cutting may also refer to an area separated by more than 1 mm from the cutting edge 7 toward the first surface 5 and the second surface 6. The fourth region may also have a fracture toughness value of less than 10 MPa·m 0.5 This fracture toughness value may be a value obtained by measuring the fracture toughness value of the Ti-based coating 10 at the surface 9 of the coating 3 parallel to the surface 4 of the substrate 2 .

[0044] The third region of the present disclosure is obtained, for example, by a sandblasting process using spherical ceramic powder having a predetermined hardness. In the sandblasting process, so-called dry sandblasting or wet sandblasting can also be used. Wet sandblasting has the advantage of being excellent in the handling properties of ceramic powder.

[0045] When the Ti-based coating 10 has the third region and the fourth region, the time of the sandblasting process can be shortened, and the coated tool 1 can be manufactured at a low cost. Hereinafter, the fracture toughness value of the fourth region is referred to as the fourth fracture toughness value. It should be noted that the lower limit of the fourth fracture toughness value may also be 1.5 MPa·m 0.5 .

[0046] When the hardness of the third region is set to the third hardness and the hardness of the fourth region is set to the fourth hardness, the third hardness may be greater than the fourth hardness. In this case, the coated tool 1 has high wear resistance.

[0047] The third hardness and the fourth hardness are not limited to specific values. For example, the third hardness may be set to about 15 to 30 GPa. The fourth hardness may be set to about 10 to 30 GPa. The third hardness and the fourth hardness may be measured in the same manner as the first hardness and the second hardness.

[0048] The first region can also be located above the third region. Additionally, the second region can also be located above the fourth region. In this case, the resistance to chipping is high, the time of the sandblasting process can be shortened, and the coated cutting tool 1 can be manufactured at low cost.

[0049] In the X-ray diffraction of the Al2O3 layer 8, the half-value width of the (104) plane can also be 0.15° or more. In this case, the coating 3 is difficult to chip and is excellent in chipping resistance. The half-value width of the (104) plane of the Al2O3 layer 8 can also be measured as follows. The (104) plane can be based on the JCPDS card number 00-010-0173. When the Al2O3 layer 8 is exposed by wet sandblasting, XRD measurement can be performed on the mirror surface obtained by mirror-polishing the surface of the exposed Al2O3 layer 8. When the Al2O3 layer 8 is not exposed, mirror-polishing treatment can be continued until the Al2O3 layer 8 is exposed, and XRD measurement can be performed on the mirror surface where the Al2O3 layer 8 is exposed. The XRD measurement of the Al2O3 layer 8 can be performed by selecting a surface with less surface roughness. The XRD measurement can also be performed using MiniFlex600 manufactured by Rigaku Corporation. Regarding the measurement conditions, it can be performed as follows: the characteristic X-ray is set to CuKβ line, the output is 40 kV, 15 mA, the transmitting-side Soller slit is 2.5°, the length-limiting slit is 5.0 mm, the divergence slit is 0.625°, the scattering slit is 8.0 mm, the receiving-side Soller slit is 2.5°, the receiving slit is 13.0 mm, the step size is set to 0.01°, the measurement speed is set to 2.0° / minute, and the scanning angle is set to 20° to 90°. It should be noted that the upper limit value of the half-value width of the (104) plane of the Al2O3 layer 8 can also be 2.0°.

[0050] The coating 3 can also have layers other than the Al2O3 layer 8 and the Ti-based coating 10. As other layers, for example, a TiC layer and a TiN layer can be cited. As Figure 3 In an example not limited as shown, the coating 3 can also have a structure in which a TiN layer 11, a Ti-based coating 10, and an Al2O3 layer 8 are sequentially stacked on the substrate 2, and can also have a structure in which a TiN layer 12 and the like are stacked on the Al2O3 layer 8. The Al2O3 layer 8 can be in contact with the Ti-based coating 10. It should be noted that for convenience, the TiN layer 11 can be referred to as the first TiN layer 11, and the TiN layer 12 can be referred to as the second TiN layer 12.

[0051] The thicknesses of the first TiN layer 11, the Ti-based coating 10, the Al2O3 layer 8, and the second TiN layer 12 are not limited to specific values. For example, the thickness of the first TiN layer 11 can also be set to 0.1 to 3.0 μm. The thickness of the Ti-based coating 10 can also be set to 1.0 to 20 μm. The thickness of the Al2O3 layer 8 can also be set to 1.0 to 20 μm. The thickness of the second TiN layer 12 can also be set to 0.1 to 10 μm.

[0052] The coated cutting tool 1 can also have a through-hole 13. The through-hole 13 can be used for installing a fixing screw, a clamping member, etc. when the coated cutting tool 1 is held in a tool holder. The through-hole 13 can be formed from the first surface 5 to the surface (lower surface) on the opposite side of the first surface 5, or can also be opened on these surfaces. It should be noted that there is no problem even if the through-hole 13 has a structure that opens in the opposing regions in the second surface 6.

[0053] <Manufacturing method of coated cutting tool>

[0054] Next, taking the case of manufacturing the coated cutting tool 1 as an example, the manufacturing method of the coated cutting tool according to the unrestricted embodiment of the present disclosure will be described.

[0055] The substrate 2 can also be manufactured first. Taking the case of manufacturing a substrate 2 made of cemented carbide as an example for explanation. First, it can be that inorganic powder such as metal carbide, nitride, carbonitride, oxide, etc. that can form the substrate 2 by firing is appropriately added and mixed with metal powder, carbon powder, etc. to obtain a mixed powder. Next, it can be that the mixed powder is formed into a prescribed tool shape by a known forming method such as stamping, casting, extrusion, cold isostatic pressing, etc. to obtain a formed body. Then, it can be that the obtained formed body is fired in a vacuum or a non-oxidizing atmosphere to obtain the substrate 2. The surface 4 of the substrate 2 can also be subjected to grinding or honing.

[0056] Next, it can be that the coating 3 is formed on the surface 4 of the obtained substrate 2 by CVD method. In addition, it can be that the wet blasting treatment is performed on the formed coating 3. Hereinafter, the coating 3 and the coated cutting tool 1 in the state before the wet blasting treatment are referred to as the untreated coating and the untreated coated cutting tool. And the untreated coating after the wet blasting treatment is referred to as the coating 3, and the untreated coated cutting tool is referred to as the coated cutting tool 1. The process before performing the wet blasting treatment can also be referred to as the first process of preparing an untreated coated cutting tool having an untreated coating on the substrate 2.

[0057] As an untreated coating, for example, it can also be that a first TiN layer 11, a Ti-based coating 10, and an Al2O3 layer 8 are successively formed on the substrate 2. Moreover, it can also be that a second TiN layer 12 or the like is formed on the Al2O3 layer 8.

[0058] The first TiN layer 11 can also be formed as follows. First, as the reaction gas composition, a mixed gas composed of titanium tetrachloride (TiCl4) gas contained at 0.1 to 10% by volume, nitrogen (N2) gas contained at 10 to 60% by volume, and the balance being hydrogen (H2) gas can be adjusted. Then, this mixed gas can be introduced into the chamber, the temperature can be set to 800 to 1010 °C, the pressure can be set to 10 to 85 kPa, and the first TiN layer 11 can be formed. It should be noted that these film-forming conditions can also be applied to the second TiN layer 12.

[0059] The Ti-based coating 10 can also be formed as follows. First, as the reaction gas composition, a mixed gas composed of titanium tetrachloride (TiCl4) gas contained at 0.1 to 10% by volume, acetonitrile (CH3CN) gas contained at 0.1 to 3.0% by volume, and the balance being hydrogen (H2) gas can be adjusted. Then, this mixed gas can be introduced into the chamber, the temperature can be set to 800 to 1050 °C, the pressure can be set to 5 to 30 kPa, and the Ti-based coating 10 can be formed.

[0060] The Al2O3 layer 8 can also be formed as follows. First, as the reaction gas composition, a mixed gas composed of aluminum trichloride (AlCl3) gas contained at 0.5 to 5% by volume, hydrogen chloride (HCl) gas contained at 0.5 to 3.5% by volume, carbon dioxide (CO2) gas contained at 0.5 to 5% by volume, hydrogen sulfide (H2S) gas contained at 0.5% or less by volume, and the balance being hydrogen (H2) gas can be adjusted. Then, this mixed gas can be introduced into the chamber, the temperature can be set to 930 to 1010 °C, the pressure can be set to 5 to 10 kPa, and the Al2O3 layer 8 can be formed.

[0061] Next, it can also be that a process of performing wet blasting on the formed untreated coating is carried out. This process can also be a second process of impinging spherical ceramic particles with a hardness (HV) of 1000 or more on the untreated coating. HV (Vickers hardness) can also be measured based on JIS Z 2244:2009. It should be noted that the upper limit value of the hardness (HV) of the spherical ceramic particles can also be 2500.

[0062] The hardness of a medium such as spherical ceramic particles can also be measured by hardness measurement based on a load-unloading test. Alternatively, when measuring the hardness, a solidified body made by mixing the medium with an embedding resin and then curing the mixture may be used. Alternatively, the hardness of the medium exposed on the ground surface may be measured after grinding the surface of the solidified body. As the embedding resin, for example, Technovit 4004 manufactured by Kulzer may be used. Alternatively, the medium to be measured and the embedding resin may be mixed at a ratio of 3:1 (mass ratio) to form a solidified body, and the surface may be ground. Alternatively, after grinding, the hardness of the portion where the medium of the solidified body is exposed may be measured. The measurement may also be performed by using a dynamic ultra-micro hardness tester DUH-211S. Alternatively, the measurement may be performed under the conditions that the indenter has an included angle of 115° between edges and is a triangular pyramid indenter (made of diamond), the test force is 49 (mN), the loading speed is 2.665 (mN / sec), and the holding time is 5 seconds. The measurement may be performed 10 times, and the average value may be measured.

[0063] The second process may be performed on the entire surface of the untreated coating, or alternatively, on a part thereof. The part of the untreated coating on which the second process is performed easily causes the Al2O3 layer 8 to have a first region, and also easily causes the Ti-based coating 10 to have a third region. The part of the untreated coating on which the second process is not performed easily causes the Al2O3 layer 8 to have a second region, and also easily causes the Ti-based coating 10 to have a fourth region.

[0064] In wet sandblasting, a sandblasting liquid containing spherical ceramic particles in a liquid may also be projected onto the untreated coating. It should be noted that the sandblasting liquid is also called a slurry. As the liquid, for example, water may be used.

[0065] The meaning of spherical ceramic particles may also refer to particles that are not obtained by crushing raw materials. To distinguish from spherical ceramic particles, ceramic particles obtained by crushing raw materials may be called angular ceramic particles. In Figure 4 a photograph of spherical ceramic particles is shown. In addition, in Figure 5 a photograph of angular ceramic particles is shown. The density of the spherical ceramic particles may also be 6 g / cm 3 or less. Spherical ceramic particles with a density of 6 g / cm 3 or less are easily dispersed in water due to their relatively small density and are suitable for wet sandblasting. For example, the density of Al2O3 particles is about 4 g / cm 3 .

[0066] As shown in Figure 5As shown in the photograph, the angular ceramic particles may also have angles in an amorphous form. The angular ceramic particles may be ceramic particles produced by crushing raw material particles or the like, or may be ceramic particles having a crushed surface and angles formed by a crushing process. Angular ceramic particles have been used in conventional wet sandblasting.

[0067] On the other hand, as Figure 4 shown in the photograph, the spherical ceramic particles may also be in a shape without angles and close to a perfect sphere. The shape of the spherical ceramic particles does not have to be a perfect sphere, and some deformation from the sphere is allowed as long as there is no crushed surface or acute angle.

[0068] It should be noted that as particles similar in shape to the spherical ceramic particles, spherical metal particles can be cited. Although the shape of the spherical metal particles is similar to that of the spherical ceramic particles, they are denser and softer than the spherical ceramic particles. For example, the density of the spherical metal particles is 7 to 8 g / cm 3 . In addition, the hardness (HV) of the spherical metal particles is less than 1000. Presumably due to this characteristic, it is difficult to obtain the coated cutting tool 1 having the first region and the third region when spherical metal particles are used. In addition, due to the high density, the spherical metal particles are difficult to disperse in water and are not suitable for wet sandblasting.

[0069] For the same reason, even in the case of spherical ceramic particles, if they contain a large amount of glass beads or glass components with a hardness (HV) of less than 1000, it is difficult to obtain the coated cutting tool 1 having the first region and the third region.

[0070] In wet sandblasting, spherical ceramic particles of various sizes can be used. When spherical ceramic particles with a large average particle diameter are used, the sandblasting time is easily shortened. The average particle diameter of the spherical ceramic particles can also be set to 200 μm or less.

[0071] In addition, the average particle diameter of the spherical ceramic particles can also be 30 μm or more and 100 μm or less. If spherical ceramic particles in this range are used, sandblasting of various untreated coatings can be reproduced with good reproducibility.

[0072] The average particle diameter of the spherical ceramic particles can also be measured by the laser diffraction method. In addition, in the case where spherical ceramic particles and angular ceramic particles are mixed, it is also possible to dry the sandblasting liquid, extract the spherical ceramic particles using SEM photographs, and use the average value of the equivalent circle diameters of 100 spherical ceramic particles obtained from the photographs.

[0073] The average circularity of the spherical ceramic particles can also be 0.82 or more. In particular, the average circularity of the spherical ceramic particles can also be 0.88 or more. In this case, the manufactured coated cutting tool has high defect resistance. It should be noted that the upper limit value of the average circularity can also be 0.98.

[0074] The average circularity is measured as follows. First, after photographing the particle image using SEM or TEM, it is also possible to measure the projected area (S) and the perimeter (L) of the particles using image analysis software (for example, "Mac-View Version.4" manufactured by Mountech). Next, it is also possible to apply the obtained measured values to the formula: 4πS / L2 to calculate the circularity. The calculation of the circularity can be performed on 100 randomly selected particles, and the average value thereof can be used as the average circularity.

[0075] Examples of the material of the spherical ceramic particles include Al2O3, ZrO2, and SiC. It should be noted that when using spherical ceramic particles of a material with a high density, the average particle diameter can also be made smaller. When using spherical ceramic particles of a material with a low density, the average particle diameter can also be made larger.

[0076] It is also possible to prepare a sandblasting liquid containing 10 to 40% by volume of spherical ceramic particles with respect to water.

[0077] Regarding the projection conditions of the sandblasting liquid, the projection pressure can be set to 0.15 to 0.30 MPa and the projection time can be set to 0.4 to 10.0 seconds. When the projection time of the sandblasting liquid exceeds 10.0 seconds, it is not suitable because the peeling of the untreated coating is likely to increase. It should be noted that when projecting the sandblasting liquid onto the untreated coating, at least a part of the Al2O3 layer 8 remains.

[0078] For example, the coated cutting tool 1 can be manufactured by the above-described process.

[0079] It should be noted that it is also possible to contain a part of angular ceramic particles in the sandblasting liquid. In such a case, 50% by volume or more of the ceramic particles can be spherical ceramic particles.

[0080] It is also possible to project a sandblasting liquid containing angular ceramic particles before projecting the sandblasting liquid containing spherical ceramic particles. In addition, it is also possible to project a sandblasting liquid containing angular ceramic particles after projecting the sandblasting liquid containing spherical ceramic particles. By projecting the sandblasting liquid containing spherical ceramic particles, even if a sandblasting liquid containing angular ceramic particles is projected, it is difficult for the fracture toughness value of the coating 3 to decrease.

[0081] It should be noted that when projecting a sandblasting liquid containing spherical ceramic particles onto an untreated coating, for example, a commercially available wet sandblasting device can also be used.

[0082] In the untreated coating tool, the untreated coating may also have a tensile stress. It should be noted that the tensile stress is not limited to a specific value. The absolute value of the tensile stress can also be set to about 50 to 500 MPa.

[0083] The untreated coating may also have a compressive stress. It should be noted that the compressive stress is not limited to a specific value. The absolute value of the compressive stress can also be set to about 50 to 2000 MPa.

[0084] The tensile stress and compressive stress can also be measured by the sin2ψ method using an X-ray stress measurement device (XRD). It should be noted that when measuring the residual stress, for the Al2O3 layer 8, the (116) plane of α-type Al2O3 can also be selected for measurement. For the Ti-based coating 10, the (422) plane of TiCN can also be selected for measurement.

[0085] In the obtained coated tool 1, the region including the cutting edge 7 can also be subjected to grinding. As a result, the region including the cutting edge 7 becomes smooth. Consequently, the build-up on the workpiece to be cut is suppressed, and the cutting edge 7 has high resistance to chipping.

[0086] It should be noted that the above manufacturing method is an example of the method for manufacturing the coated tool 1. Therefore, it goes without saying that the coated tool 1 is not limited to the coated tool manufactured by the above manufacturing method.

[0087] <Cutting tool>

[0088] Next, regarding the cutting tool 101 of an unrestricted embodiment of the present disclosure, a case where it has the above coated tool 1 is taken as an example and referred to Figure 6 for a detailed description.

[0089] As Figure 6 shown in an unrestricted example, the cutting tool 101 may have: a tool shank 102 having a length from a first end 102a to a second end 102b and having a tool groove 103 on one side of the first end 102a; and a coated tool 1 located in the tool groove 103. When the cutting tool 101 has the coated tool 1, the coated tool 1 is excellent in chipping resistance, so that long-term stable cutting can be performed.

[0090] The tool groove 103 may also be a part for mounting the coated tool 1. The tool groove 103 may open on the outer peripheral surface of the tool shank 102 and the end surface on one side of the first end 102a.

[0091] The coated cutting tool 1 can also be mounted in the tool groove 103 in such a manner that the cutting edge 7 protrudes outward from the tool shank 102. Additionally, the coated cutting tool 1 can also be mounted in the tool groove 103 by means of a fixing screw 104. That is, it is also possible to insert the fixing screw 104 into the through-hole 13 of the coated cutting tool 1, insert the tip of the fixing screw 104 into the threaded hole formed in the tool groove 103 and thread the threaded portions together, whereby the coated cutting tool 1 is mounted in the tool groove 103. It is also possible to sandwich a sheet between the coated cutting tool 1 and the tool groove 103.

[0092] As the material of the tool shank 102, for example, steel and cast iron can be cited. When the material of the tool shank 102 is steel, the tool shank 102 has high toughness.

[0093] In Figure 6 In one example shown, a cutting tool 101 for so-called turning is illustrated. As turning, for example, internal diameter machining, external diameter machining, and grooving can be cited. It should be noted that the use of the cutting tool 101 is not limited to turning. For example, there is no problem even if the cutting tool 101 is used for rotary turning.

[0094] Hereinafter, examples will be given to explain the present disclosure in detail, but the present disclosure is not limited to the following examples.

[0095]

Examples

[0096] [Specimen No. 1 - 11]

[0097] <Manufacture of Coated Cutting Tool>

[0098] First, a substrate is manufactured. Specifically, WC powder with an average particle diameter of 1.2 μm is added and mixed with metal Co powder with an average particle diameter of 1.5 μm at a ratio of 6% by mass, TiC (titanium carbide) powder is added and mixed at a ratio of 2.0% by mass, and Cr3C2 (chromium carbide) powder is added and mixed at a ratio of 0.2% by mass to produce a mixed raw material powder. Next, the mixed raw material powder is press-formed into a cutting tool shape (CNMG120408) to obtain a formed body. The obtained formed body is subjected to a debinding treatment and fired at 1400 °C for 1 hour in a vacuum of 0.5 - 100 Pa to manufacture a substrate made of cemented carbide. Tip treatment (R honing) is performed on one side of the rake face (first face) of the manufactured substrate by brushing.

[0099] Next, an untreated coating is formed on the substrate. Specifically, a first TiN layer, a Ti-based coating, an Al2O3 layer, and a second TiN layer are sequentially formed on the substrate from one side of the substrate. The film-forming conditions and thickness are as follows. It should be noted that the thickness is a value obtained by cross-section measurement using SEM.

[0100] (First TiN layer)

[0101] TiCl4 gas: 1.0 vol%

[0102] N2 gas: 55.0 vol%

[0103] H2 gas: the remainder

[0104] Temperature: 850 °C

[0105] Pressure: 16 kPa

[0106] Thickness: 1.0 μm

[0107] (Ti-based coating)

[0108] TiCl4 gas: 7.0 vol%

[0109] CH3CN gas: 0.5 vol%

[0110] H2 gas: the remainder

[0111] Temperature: 850 °C

[0112] Pressure: 10 kPa

[0113] Thickness: 7.0 μm

[0114] (Al2O3 layer)

[0115] AlCl3 gas: 4.2 vol%

[0116] HCl gas: 0.9 vol%

[0117] CO2 gas: 4.5 vol%

[0118] H2S gas: 0.3 vol%

[0119] H2 gas: the remainder

[0120] Temperature: 950 °C

[0121] Pressure: 9 kPa

[0122] Thickness: 8.0 μm

[0123] (Second TiN layer)

[0124] TiCl4 gas: 3.0 vol%

[0125] N2 gas: 40.0 vol%

[0126] H2 gas: the remainder

[0127] Temperature: 1010 °C

[0128] Pressure: 30 kPa

[0129] Thickness: 2.0 μm

[0130] Next, as the medium, the abrasive slurry was adjusted so as to contain spherical Al2O3 particles having an average particle diameter shown in Table 1, spherical particles composed of zircon (ZrSiO4), and angular Al2O3 particles in amounts of 25% by volume with respect to water. It should be noted that the hardness (HV) of the medium is a value measured as follows.

[0131] (Medium hardness)

[0132] The hardness of the medium used in the sandblasting process was measured by hardness measurement based on a load-unload test. First, the medium to be measured was fixed using an embedding resin (Technovit 4004 manufactured by Kulzer) and the surface was polished. Specifically, 1 g of a resin obtained by mixing a liquid curing resin and a curing agent at a mass ratio of 3:1 was added with 3 g of Al2O3 powder, and after mixing, it was cured at room temperature (23°C) for about 1 hour to obtain a cured body. After that, the following order of polishing the cured body was used. After polishing, the hardness of the part of the medium exposed on the cured body was measured. The measurement was carried out using a dynamic ultra-micro hardness tester DUH-211S. The measurement was carried out under the conditions that the indenter was a triangular pyramid indenter (made of diamond) with an included angle between edges of 115°, the test force was 49 (mN), the load speed was 2.665 (mN / sec), and the holding time was 5 seconds. The measurement was carried out 10 times, and the average value was measured.

[0133] The adjusted abrasive slurry was projected onto the uncoated tool at a pressure of compressed air (projection pressure) of 0.2 MPa for the time shown in Table 1 to obtain a coated tool. It should be noted that the abrasive slurry was projected onto the regions related to cutting on the first surface and the second surface. The regions related to cutting were regions less than 1 mm in the directions of the first surface and the second surface from the cutting edge.

[0134] ◎[Table 1]

[0135]

[0136] <Evaluation>

[0137] Regarding the obtained coated tool, the first to fourth fracture toughness values and the first to fourth hardness were measured. In addition, the half-value width of the (104) plane in the region related to cutting was measured. Moreover, the obtained coated tool was used for cutting evaluation, and the defect resistance was evaluated. The measurement methods are shown below, and the results are shown in Tables 2 and 3.

[0138] (First to Fourth Fracture Toughness Values)

[0139] An indentation test was performed on the surface that had been mirror-finished using a nanoindenter. A field emission scanning electron microscope (FE-SEM) was used to observe cracks in the obtained indentation, and the fracture toughness value was measured. The measurement was performed using the ultra-microindentation hardness tester ENT-1100b / a manufactured by Elionix, Inc. as the nanoindenter. The indentation load was 700 (mN), and the indenter used in the measurement was the glass indenter ENT-20-13 manufactured by Toyo-Technica Co., Ltd. The fracture toughness value was measured based on JIS R 1607:2015. The observation of cracks was performed using the JSM-7100F manufactured by JEOL Ltd.

[0140] When the Al2O3 layer was exposed by wet blasting treatment, the fracture toughness value was measured on the mirror surface obtained by mirror-polishing the surface of the exposed Al2O3 layer. When the Al2O3 layer was not exposed, the mirror-polishing treatment was continued until the Al2O3 layer was exposed, and the fracture toughness value was measured on the mirror surface where the Al2O3 layer was exposed.

[0141] The fracture toughness value of the Ti-based coating was also obtained by performing mirror-polishing until the Ti-based coating was exposed from the surface of the coating and measuring it on the mirror surface of the exposed Ti-based coating.

[0142] It should be noted that in the mirror-polishing, a material obtained by adjusting diamond paste with an average particle diameter of 1.4 μm manufactured by Tomei Diamond Co., Ltd. and olive oil manufactured by Sankei Kogyo Co., Ltd. to a paste concentration of 25 mass% was used. In addition, the mirror-polishing was performed in such a way that the mirror surface was parallel to the surface of the substrate.

[0143] (First to Fourth Hardness)

[0144] The measurement was performed by an indentation test using a nanoindenter. The ultra-microindentation hardness tester ENT-1100b / a manufactured by Elionix, Inc. was used as the nanoindenter. The indentation load was 700 (mN), and the indenter used in the measurement was the glass indenter ENT-20-13 manufactured by Toyo-Technica Co., Ltd.

[0145] (Half-value Width of the (104) Plane in the Region Related to Cutting)

[0146] The half-value width of the (104) plane of the area involving cutting on the surface that has been subjected to wet sandblasting treatment was measured. The (104) plane of the Al2O3 layer was based on the JCPDS card number 00-010-0173. When the Al2O3 layer was exposed by wet sandblasting treatment, XRD measurement was performed on the mirror surface obtained by mirror polishing the surface of the exposed Al2O3 layer. When the Al2O3 layer was not exposed, the mirror polishing treatment was continued until the Al2O3 layer was exposed, and XRD measurement was performed on the exposed mirror surface of the Al2O3 layer. For the XRD measurement of the Al2O3 layer, a plane with less surface unevenness was selected. The XRD measurement was carried out using MiniFlex600 manufactured by Rigaku Corporation. For the measurement conditions, it can also be carried out as follows: the characteristic X-ray is set to CuKβ line, the output is 40 kV, 15 mA, the Soller slit on the emitting side is 2.5°, the length limiting slit is 5.0 mm, the divergence slit is 0.625°, the scattering slit is 8.0 mm, the Soller slit on the receiving side is 2.5°, the receiving slit is 13.0 mm, the step size is set to 0.01°, the measurement speed is set to 2.0° / minute, and the scanning angle is set to 20° to 90°.

[0147] (Cutting evaluation)

[0148] The interrupted cutting test was carried out under the following conditions.

[0149] Workpiece to be cut: Carbon steel for mechanical structures (steel bar with 16 grooves cut on S45C)

[0150] Tool shape: CNMG120408

[0151] Cutting speed: 48 m / min

[0152] Feed rate: 0.27 mm / rev

[0153] Depth of cut: 1.0 mm

[0154] Others: Water-soluble cutting fluid was used

[0155] Evaluation item: Measure the number of impacts until defect occurs

[0156] ◎[Table 2]

[0157]

[0158] ◎[Table 3]

[0159]

[0160] Specimen No.1 was not treated with projected abrasive blast liquid on the untreated coating. In other words, Specimen No.1 is a coated cutting tool with only a coating formed on the substrate. In the fracture toughness values of the Al2O3 layer of Specimen No.1, both the first side and the second side are 0.8 MPa·m 0.5 .

[0161] For Specimen No.2, abrasive blast liquid containing angular ceramic particles was projected onto the first side and the second side. In Specimen No.2, the fracture toughness value of the Al2O3 layer is higher than that of untreated Specimen No.1, and both the first side and the second side are 1.5 MPa·m 0.5 .

[0162] For Specimen No.3 and 4, abrasive blast liquid containing spherical zircon (ZrSiO4) particles was projected onto the first side and the second side. In Specimen No.3 and 4, the fracture toughness value of the Al2O3 layer is higher than that of untreated Specimen No.1, and both the first side and the second side are 1.5 MPa·m 0.5 or 2.0 MPa·m 0.5 .

[0163] The fracture toughness values of the Al2O3 layer of Specimen No.1 to 4 are all relatively low values.

[0164] In contrast, for Specimen No.5 to 11 which are the coated cutting tools of the present disclosure, the Al2O3 layer has regions with fracture toughness values of 5.0 MPa·m 0.5 or more or 6.5 MPa·m 0.5 and is excellent in defect resistance.

[0165] It should be noted that for the spherical Al2O3 particles in Specimen No.5 to 11 and the angular Al2O3 particles in Specimen No.2, the average roundness was measured. Specifically, first, after photographing the particle images using SEM, the projected area (S) and the perimeter (L) of the particles were measured using image analysis software ("Mac-View Version.4" manufactured by mountech). Next, the measured values obtained were applied to the formula: 4πS / L2 to calculate the roundness. The calculation of roundness was performed for 100 randomly selected particles, and the average value was taken as the average roundness. The measurement results of the average roundness are as follows.

[0166] (Average roundness)

[0167] Spherical Al2O3 particles in Specimen No.5 to 11: 0.90

[0168] Angular Al2O3 particles in Specimen No.2: 0.74

[0169] Explanation of reference numerals

[0170] 1... Coated cutting tool

[0171] 2... Substrate

[0172] 3... Coating

[0173] 4... Surface

[0174] 5... First surface

[0175] 6... Second surface

[0176] 7... Cutting edge

[0177] 8... Al2O3 layer

[0178] 9... Surface

[0179] 10... Ti-based coating

[0180] 11... TiN layer (first TiN layer)

[0181] 12... TiN layer (second TiN layer)

[0182] 13... Through hole

[0183] 101... Cutting tool

[0184] 102... Tool shank

[0185] 102a... First end

[0186] 102b... Second end

[0187] 103... Tool groove

[0188] 104... Fixing screw.

Claims

1. A coated cutting tool having a substrate and a coating located on the substrate, wherein, the coated cutting tool includes: a first face; a second face adjacent to the first face; and a cutting edge located at at least a part of the ridge line portion between the first face and the second face, the coating has an Al2O3 layer, The Al2O3 layer has a first region where the fracture toughness value of the Al2O3 layer is 5 MPa·m or more when measured on the surface of the coating parallel to the surface of the substrate, and a second region where the fracture toughness value of the Al2O3 layer is less than 5 MPa·m when measured on the surface of the coating parallel to the surface of the substrate. 0.5 0.5 ​ when the hardness of the first region is set as the first hardness and the hardness of the second region is set as the second hardness, the second hardness is greater than the first hardness.

2. The coated cutting tool according to claim 1, wherein, the Al2O3 layer has the first region on the first face and the second face respectively.

3. The coated cutting tool according to claim 1, wherein, the Al2O3 layer has the first region on the first face and has the second region on the second face.

4. A coated cutting tool having a substrate and a coating located on the substrate, wherein, the coated cutting tool includes: a first face; a second face adjacent to the first face; and a cutting edge located at at least a part of the ridge line portion between the first face and the second face, the coating has an Al2O3 layer, The Al2O3 layer has a first region where, when the fracture toughness value of the Al2O3 layer is measured on the surface of the coating parallel to the surface of the substrate, the fracture toughness value is 5 MPa·m 0.5 or more, the coating has a Ti-based coating between the substrate and the Al2O3 layer, The Ti-based coating has a fracture toughness value of 10 MPa·m when the fracture toughness value of the Ti-based coating is measured on the surface of the coating parallel to the surface of the substrate 0.5 or more in the third region.

5. The coated cutting tool according to claim 4, wherein, The Ti-based coating has a fourth region where, when the fracture toughness value of the Ti-based coating is measured on the surface of the coating parallel to the surface of the substrate, the fracture toughness value is less than 10 MPa·m 0.5 and, when the hardness of the third region is defined as the third hardness and the hardness of the fourth region is defined as the fourth hardness, the third hardness is greater than the fourth hardness.

6. The coated cutting tool according to claim 5, wherein, The Al2O3 layer has a second region where the fracture toughness value of the Al2O3 layer is less than 5 MPa·m when measured on the surface of the coating parallel to the surface of the substrate. 0.5 The first region is located above the third region, and the second region is located above the fourth region.

7. The coated cutting tool according to any one of claims 1 to 6, wherein, the half-value width of the (104) plane in X-ray diffraction of the Al2O3 layer is 0.15° or more.

8. A cutting tool, wherein, the cutting tool has: a tool shank having a length from a first end to a second end and having a tool groove on the side of the first end; and the coated cutting tool according to any one of claims 1 to 7 located in the tool groove.

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