Coated cutting tool and cutting tool

Abstract

A non-limiting example of a coated cutting tool of the present invention has a substrate and a coating on the substrate. The coated cutting tool has a first face, a second face adjacent to the first face, and a cutting edge on at least a portion of a ridge line between the first face and the second face. The coating has a Ti-based coating. The Ti-based coating has a fracture toughness value of 10 MPa·m 0.5 The first region above.

Description

[0001] Cross-referencing of related applications

[0002] This application claims priority to Japanese Patent Application No. 2020-112956, filed on June 30, 2020, the full disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates to coated cutting tools and cutting tools having the coated cutting tools. Background Technology

[0004] Coated cutting tools, such as cutting tools, have a coating on a substrate. The coating is formed by CVD or PVD. As an example of a coating formed by CVD, a coating formed by sequentially stacking a TiN layer, a TiCN layer, and an Al2O3 layer on a substrate can be cited.

[0005] Coatings formed by CVD often exhibit significant residual stress. To mitigate this residual stress, ceramic particles are projected into the coating.

[0006] For example, Japanese Patent No. 4739235 (Patent Document 1) describes a shot peening treatment of a coating using ceramic abrasive particles. Summary of the Invention

[0007] A non-limiting example of the coated cutting tool of the present invention includes a substrate and a coating disposed on the substrate. The coated cutting tool comprises: a first surface; a second surface adjacent to the first surface; and a cutting edge located on at least a portion of the ridge portion of the first surface and the second surface. The coating is a Ti-based coating. The Ti-based coating has a fracture toughness value of 10 MPa·m when measured on a surface of the coating parallel to the surface of the substrate. 0.5 The first area above. Attached Figure Description

[0008] Figure 1 This is a perspective view of a coated cutting tool representing a non-limiting embodiment of the present invention.

[0009] Figure 2 yes Figure 1 The cross-sectional view of section II-II of the coated cutting tool shown.

[0010] Figure 3 yes Figure 2 A magnified view of the area near the coating on the coated cutting tool.

[0011] Figure 4 This is a SEM image of spherical ceramic particles.

[0012] Figure 5 This is a SEM image of angular ceramic particles.

[0013] Figure 6 This is a perspective view of a cutting tool representing a non-limiting embodiment of the present invention. Detailed Implementation

[0014] Coated Cutting Tools

[0015] Hereinafter, a method for manufacturing a coated cutting tool 1 according to a non-limiting embodiment of the present invention will be described in detail using the accompanying drawings. However, in the figures referred to below, only the main components necessary for illustrating the embodiments are simplified for ease of explanation. Therefore, the coated cutting tool 1 may include any structural components not shown in the referenced figures. In addition, the component dimensions in the figures do not faithfully represent the actual dimensions of the structural components or the dimensional ratios of each component.

[0016] exist Figures 1-3 In the example shown, a cutting insert suitable for use with cutting tools is illustrated. Besides cutting tools, coated tool 1 can also be used for wear-resistant parts such as sliding parts and molds, tools such as digging tools and cutting tools, and impact-resistant parts. Furthermore, the applications of coated tool 1 are not limited to those illustrated.

[0017] The coated cutting tool 1 may have a substrate 2 and a coating 3 located on the substrate 2.

[0018] Examples of materials for the substrate 2 include cemented carbide, ceramics, and metals. Examples of cemented carbides include those composed of a binder phase of ferrous metals such as Co (cobalt) or Ni (nickel), which combines WC (tungsten carbide) with at least one of carbides, nitrides, or carbonitrides selected from the groups of metals in groups 4, 5, and 6 of the periodic table other than WC. Other examples of cemented carbides include Ti-based cermets. Examples of ceramics include Si3N4 (silicon nitride), Al2O3 (alumina), diamond, and cBN (cubic boron nitride). Examples of metals include carbon steel, high-speed steel, and alloy steel. However, the material of the substrate 2 is not limited to the examples listed.

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

[0020] Coating 3 can be formed by chemical vapor deposition (CVD). In other words, coating 3 can be a CVD film.

[0021] The coating 3 is not limited to a specific thickness. For example, the thickness of the coating 3 can be set from 1 to 30 μm. Furthermore, the thickness, structure, and shape of the crystals constituting the coating 3 can be measured, for example, by cross-sectional observation using an electron microscope. Examples of electron microscopes include, for example, scanning electron microscopes (SEM) and transmission electron microscopes (TEM).

[0022] Coated cutting tool 1, such as Figure 1 and Figure 2 The non-limiting example shown 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 on at least a portion of the edge portion of the first surface 5 and the second surface 6.

[0023] The first face 5 can be the rake face. The entire first face 5 can be the rake face, or a portion of it can be the rake face. For example, the area along the cutting edge 7 of the first face 5 can be the rake face.

[0024] The second surface 6 can be the flank face. The entire surface of the second surface 6 can be the flank face; alternatively, a portion of it can also be the flank face. For example, the area along the cutting edge 7 within the second surface 6 can be the flank face.

[0025] The cutting edge 7 can be located on a portion of the edge, or it can be located on the entire edge. The cutting edge 7 can be used for cutting the workpiece.

[0026] Coated cutting tool 1, such as Figure 1 As shown in the non-limiting example, it can be a quadrilateral plate shape. Furthermore, the shape of the coating tool 1 is not limited to a quadrilateral plate shape. For example, the first surface 5 can also be triangular, pentagonal, hexagonal, or circular. Additionally, the coating tool 1 can also be cylindrical.

[0027] The coating 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. In addition, the height from the first surface 5 to the surface (lower surface) located on the opposite side of the first surface 5 can be set to about 5 to 20 mm.

[0028] Here, coating 3 is as follows Figure 3 As shown in one non-limiting example, it may have a Ti-based coating 8.

[0029] Ti-based coating 8 can contain TiCN, TiC, or TiN particles. Alternatively, Ti-based coating 8 can also be a layer containing TiCN as the main component. "Main component" means the component with the highest mass percentage compared to other components. These aspects are defined in the same way in other layers.

[0030] The Ti-based coating 8 can have a first region. The fracture toughness value of the first region can be 10 MPa·m. 0.5 The above. This fracture toughness value can be the value measured when the fracture toughness of the Ti-based coating 8 is measured on the surface 9 of the coating 3, which is parallel to the surface 4 of the substrate 2.

[0031] The term "parallel" as used above is not limited to strict parallelism; a tilt of approximately ±10° is permissible. Furthermore, the fracture toughness value can be measured by performing an indentation test on the mirror-finished surface using a nanoindenter, and then observing the cracks in the resulting indentation using a field emission scanning electron microscope (FE-SEM). In the mirror polishing process, diamond polishing paste with an average particle size of 1–3 μm, manufactured by TOMEI DIAMOND Co., Ltd., and olive oil manufactured by Yamagata Sangyo Co., Ltd., are used, with the paste concentration adjusted to 20–30% by mass. For example, the nanoindenter can be the ENT-1100b / a ultra-micro indentation hardness tester manufactured by Elionix Co., Ltd. The indentation load is 700 mN, and the indenter used for measurement can be the Berkovich ENT-20-13 indenter manufactured by Toyo Technical Co., Ltd. The fracture toughness value can be measured according to JIS R 1607:2015. Cracks can be observed using the JSM-7100F manufactured by Nippon Electronics Co., Ltd.

[0032] When the Ti-based coating 8 has the aforementioned first region, the coating 3 is less prone to chipping, thus exhibiting excellent chipping resistance. Furthermore, the entire Ti-based coating 8 can be composed of the first region, or only a portion of the Ti-based coating 8 can be composed of the first region. Hereinafter, the fracture toughness value of the first region will be referred to as the first fracture toughness value. The upper limit of the first fracture toughness value can be 20 MPa·m. 0.5 .

[0033] The Ti-based coating 8 can also have a first region on the first surface 5 and the second surface 6 respectively. In this case, the first surface 5 and the second surface 6 are less prone to chipping.

[0034] The Ti-based coating 8 can also have a second region. The Ti-based coating 8 of the coated tool 1 does not need to possess high fracture toughness in all areas. For example, a second region can be provided in areas that are not involved in cutting, or in areas that, even if involved in cutting, will not be subjected to large forces and impacts. Furthermore, the area not involved in cutting is defined as a region at least 1 mm away from the cutting edge 7 in the direction of the first face 5 and the second face 6. The fracture toughness value of the second region can be lower than 10 MPa·m. 0.5 The fracture toughness value can be the value measured on the surface 9 of the coating 3, which is parallel to the surface 4 of the substrate 2, when measuring the fracture toughness of the Ti-based coating 8.

[0035] The first region of the present invention is obtained, for example, by using spherical ceramic powder having a specified hardness through a shot peening process. In the shot peening process, so-called dry shot peening or wet shot peening can be used. Wet shot peening has the advantage of excellent operability of ceramic powder.

[0036] When the Ti-based coating 8 has the first and second regions described above, the shot peening process time can be shortened, and the coated tool 1 can be manufactured at a lower cost. Hereinafter, the fracture toughness value of the second region will be referred to as the second fracture toughness value. Furthermore, the lower limit of the second fracture toughness value can be 1.5 MPa·m. 0.5 .

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

[0038] The first and second hardness are not limited to specific values. For example, the first hardness can be set to approximately 15–30 GPa, and the second hardness can be set to approximately 10–30 GPa. The first and second hardnesses, for example, can be measured using a nanoindenter through an indentation test, similar to the measurement of the fracture toughness value of the Ti-based coating 8. For example, the ENT-1100b / a ultra-micro indentation hardness tester manufactured by Elionix Corporation can be used as a nanoindenter. The indentation load is 700 mN, and the indenter used for measurement can be the ENT-20-13 Glass indenter manufactured by Toyo Technical Corporation.

[0039] The Ti-based coating 8 can have a first region on the first surface 5, and a second region on the second surface 6. In this case, the coated tool 1 has high wear resistance and chipping resistance.

[0040] Coating 3 may have an Al2O3 layer 10 on top of the Ti-based coating 8. The Al2O3 layer 10 may be a layer containing Al2O3 particles. Alternatively, the Al2O3 layer 10 may be a layer containing Al2O3 as the main component.

[0041] The Al2O3 layer 10 can have a third region. The fracture toughness value of the third region can be 5 MPa·m. 0.5 The above. This fracture toughness value can be the value measured on the surface 9 of the coating 3, which is parallel to the surface 4 of the substrate 2, when measuring the fracture toughness of the Al2O3 layer 10.

[0042] When the Al2O3 layer 10 has the aforementioned third region, the coating 3 is less prone to chipping, thus exhibiting excellent chipping resistance. Furthermore, the entire Al2O3 layer 10 can be composed of the third region, or a portion of the Al2O3 layer 10 can be composed of the third region. Hereinafter, the fracture toughness value of the third region will be referred to as the third fracture toughness value. The upper limit of the third fracture toughness value can be 10 MPa·m. 0.5 .

[0043] The Al2O3 layer 10 may have a fourth region. The Al2O3 layer 10 of the coated tool 1 does not need to possess high fracture toughness in all areas. For example, a fourth region may be provided in areas that do not participate in cutting, or in areas that, even if they do participate in cutting, will not be subjected to large forces and impacts. Furthermore, the area that does not participate in cutting is defined as a region that is at least 1 mm away from the cutting edge 7 in the direction of the first face 5 and the second face 6. The fracture toughness value of the fourth region can be lower than 5 MPa·m. 0.5 The fracture toughness value can be the value measured on the surface 9 of the coating 3, which is parallel to the surface 4 of the substrate 2, when measuring the fracture toughness of the Al2O3 layer 10.

[0044] The third region of the invention is obtained, for example, by using spherical ceramic powder having a specified hardness through a shot peening process. In the shot peening process, so-called dry shot peening or wet shot peening can be used. Wet shot peening has the advantage of excellent operability of ceramic powder.

[0045] When the Al2O3 layer 10 has the aforementioned third and fourth regions, the shot peening process time can be shortened, and the coated tool 1 can be manufactured at a lower cost. Hereinafter, the fracture toughness value of the fourth region will be referred to as the fourth fracture toughness value. Furthermore, the lower limit of the fourth fracture toughness value can be 0.3 MPa·m. 0.5 .

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

[0047] The third and fourth hardness values ​​are not limited to specific values. For example, the third hardness can be set to approximately 10–30 GPa, and the fourth hardness can be set to approximately 15–30 GPa. The third and fourth hardness values ​​can be measured in the same way as the first and second hardness values.

[0048] The first region can be located below the third region, and the second region can be located below the fourth region. In this case, the chipping resistance is high, the shot peening process time can be shortened, and the coated cutting tool 1 can be manufactured at low cost.

[0049] In X-ray diffraction, the full width at half maximum (FWHM) of the (104) crystal plane of Al2O3 layer 10 can be greater than 0.15°. Under these conditions, coating 3 is less prone to chipping and exhibits excellent chipping resistance. The FWHM of the (104) crystal plane of Al2O3 layer 10 can be measured as follows. The (104) crystal plane can be referenced using JCPDS card number 00-010-0173. When Al2O3 layer 10 is exposed by wet shot peening, the surface of the exposed Al2O3 layer 10 can be mirror-polished, and XRD measurements can be performed on the resulting mirror surface. When Al2O3 layer 10 is not exposed, mirror polishing can continue until Al2O3 layer 10 is exposed, and XRD measurements can be performed on the exposed mirror surface of Al2O3 layer 10. XRD measurements of Al2O3 layer 10 can be performed on a surface with fewer surface irregularities. XRD measurements can be performed using a MiniFlex600 manufactured by Rigaku Corporation. The measurement conditions were as follows: the characteristic X-rays were CuKβ rays, the output power was 40 kV, the amplitude was 15 mA, the emission-side Soler slit was 2.5°, the length-limiting slit was 5.0 mm, the divergence slit was 0.625°, the scattering slit was 8.0 mm, the receiving-side Soler slit was 2.5°, the receiving slit was 13.0 mm, the step size was 0.01°, the measurement speed was 2.0° / min, and the scanning angle was 20° to 90°. Furthermore, the upper limit of the full width at half maximum (FWHM) of the (104) crystal plane of the Al2O3 layer 10 could be 2.0°.

[0050] Coating 3 may also have layers other than Ti-based coating 8 and Al2O3 layer 10. Other examples of such layers include TiC and TiN layers. Coating 3 as... Figure 3 As a non-limiting example, the structure shown can be formed by sequentially stacking a TiN layer 11, a Ti-based coating 8, and an Al2O3 layer 10 on a substrate 2. Alternatively, it can be a structure in which a TiN layer 12 is also stacked on top of the Al2O3 layer 10. The Al2O3 layer 10 can be in contact with the Ti-based coating 8. Furthermore, for convenience, the TiN layer 11 can be referred to as the first TiN layer 11, and the TiN layer 12 as the second TiN layer 12.

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

[0052] The coated cutting tool 1 may have a through hole 13. The through hole 13 can be used to install a fixing screw or a clamping component when the coated cutting tool 1 is held on the tool holder. The through hole 13 may be formed from the first surface 5 to the surface (lower surface) located opposite to the first surface 5, and openings may be made on these surfaces. Furthermore, there is no problem with the through hole 13 being configured to open in a region opposite to the second surface 6.

[0053] <Manufacturing Method of Coated Cutting Tools>

[0054] Next, taking the manufacture of coated tool 1 as an example, the method for manufacturing a coated tool according to a non-limiting embodiment of the present invention will be described.

[0055] Initially, a substrate 2 can be fabricated. As an example, a substrate 2 made of cemented carbide can be used for illustration. First, metal powder, carbon powder, etc., can be appropriately added to inorganic powders such as metal carbides, nitrides, carbonitrides, and oxides that can form the substrate 2 by firing, to obtain a mixed powder. Second, this mixed powder can be formed into a specified tool shape using known forming methods such as stamping, casting, extrusion, and cold isostatic pressing to obtain a shaped body. Then, the obtained shaped body can be fired in a vacuum or a non-oxidizing atmosphere to obtain the substrate 2. The surface 4 of the substrate 2 can be ground or honed.

[0056] Next, a film coating 3 can be formed on the surface 4 of the obtained substrate 2 using a CVD method. Furthermore, wet shot peening can be performed on the film-formed coating 3. Hereinafter, the coating 3 and the coated cutting tool 1 in their state before wet shot peening will be referred to as the untreated coating and the untreated coated cutting tool, respectively. Then, the untreated coating and the untreated coated cutting tool after wet shot peening will be referred to as coating 3 and coated cutting tool 1, respectively. The process prior to wet shot peening can also be referred to as the first process of preparing an untreated coated cutting tool with an untreated coating on the substrate 2.

[0057] As an untreated coating, for example, a first TiN layer 11, a Ti-based coating 8, and an Al2O3 layer 10 can be sequentially formed on the substrate 2. A second TiN layer 12 can also be formed on the Al2O3 layer 10.

[0058] The first TiN layer 11 is formed as follows. First, the reaction gas composition can be adjusted to include a mixture of titanium tetrachloride (TiCl4) gas (0.1–10 vol%), nitrogen (N2) gas (10–60 vol%), and the remainder hydrogen (H2). Then, this mixture can be introduced into a furnace, and the temperature and pressure can be set to 800–1010 °C and 10–85 kPa to form the first TiN layer 11. This same film formation condition can also be applied to the second TiN layer 12.

[0059] The Ti-based coating 8 can be formed as follows. First, the reaction gas composition can be adjusted to include: 0.1–10% by volume of titanium tetrachloride (TiCl4), 0.1–3.0% by volume of acetonitrile (CH3CN), and the remainder being hydrogen (H2). Then, this gas mixture can be introduced into a furnace, the temperature set to 800–1050 °C, and the pressure set to 5–30 kPa, to form the Ti-based coating 8.

[0060] The Al2O3 layer 10 can be formed as follows. First, the reaction gas composition can be adjusted to include the following mixture: aluminum trichloride (AlCl3) gas at 0.5–5% by volume, hydrogen chloride (HCl) gas at 0.5–3.5% by volume, carbon dioxide (CO2) gas at 0.5–5% by volume, hydrogen sulfide (H2S) gas at less than 0.5% by volume, with the remainder being hydrogen (H2). Then, this mixture can be introduced into a furnace, the temperature set to 930–1010 °C, and the pressure set to 5–10 kPa, to form the Al2O3 layer 10.

[0061] Next, a wet shot peening process can be performed on the untreated coating. This process can be a second step in which spherical ceramic particles with a hardness (HV) of 1000 or higher collide with the untreated coating. HV (Vickers hardness) can be measured according to JIS Z2244:2009. Furthermore, the upper limit for the hardness (HV) of the spherical ceramic particles can be 2500.

[0062] The hardness of media such as spherical ceramic particles can be measured using a load-unload test. For hardness measurement, a cured body is prepared by mixing the media and potting resin and then curing the mixture. The surface of this cured body can be ground, and the hardness of the exposed media can be measured. For example, Kulzer's Technovit 4004 potting resin can be used. The media to be measured can be mixed with the potting resin in a 3:1 (mass ratio) to form a cured body, and the surface can be ground. After grinding, the hardness of the exposed media portion of the cured body can be measured. The measurement can be performed using a dynamic microhardness tester DUH-211S. Measurements are performed under the following conditions: a 115° inter-edge angle of the measuring indenter, a diamond-tipped indenter, a test force of 49 mN, a load speed of 2.665 mN / s, and a holding time of 5 seconds. Ten measurements can be taken, and the average value is calculated.

[0063] The second process can be performed on the entire surface of the untreated coating, or it can be performed on a portion of it. The portion of the untreated coating that has undergone the second process tends to become a Ti-based coating 8 with a first region, and also tends to become an Al2O3 layer 10 with a third region. The portion of the untreated coating that has not undergone the second process tends to become a Ti-based coating 8 with a second region, and also tends to become an Al2O3 layer 10 with a fourth region.

[0064] In wet shot peening, an untreated coating is peened with a slurry containing spherical ceramic particles. This slurry is also called a paste. Water can be used as an example of such a liquid.

[0065] The term "spherical ceramic particles" refers to particles that are not obtained by crushing raw materials. To distinguish them from spherical ceramic particles, ceramic particles obtained by crushing raw materials are called angular ceramic particles. Figure 4 The image shows spherical ceramic particles. Additionally, Figure 5 The image shows angular ceramic particles. Spherical ceramic particles have a specific gravity of up to 6 g / cm³. 3 The specific gravity is 6 g / cm³. 3 The following spherical ceramic particles, due to their low specific gravity, are more easily dispersed in water and are suitable for wet shot peening. For example, Al2O3 particles have a specific gravity of approximately 4 g / cm³. 3 .

[0066] like Figure 5 The photograph shown illustrates that angular ceramic particles can have irregular angles. Angular ceramic particles can be manufactured by crushing raw material particles, or by forming broken surfaces and angles through a crushing process. Angular ceramic particles are currently used in wet shot peening processes.

[0067] On the other hand, such as Figure 4 The photograph shown depicts spherical ceramic particles, which can also be nearly spherical without sharp angles. The shape of the spherical ceramic particles does not need to be perfectly spherical; as long as there are no broken surfaces or acute angles, some deformation deviating from a sphere is permissible.

[0068] Furthermore, spherical metal particles can also be listed as examples of particles with similar shapes to spherical ceramic particles. Spherical metal particles have a similar shape to spherical ceramic particles, but they are denser and softer. For example, the specific gravity of spherical metal particles is 7–8 g / cm³. 3 Furthermore, the hardness (HV) of spherical metal particles is less than 1000. Based on this characteristic, it can be inferred that if spherical metal particles are used, it would be difficult to obtain a coated cutting tool 1 with both a first and a third region. In addition, due to their higher specific gravity, spherical metal particles are difficult to disperse in water, making them unsuitable for wet shot peening.

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

[0070] In wet shot peening, spherical ceramic particles of various sizes can be used. Using spherical ceramic particles with a large average particle size can easily shorten the peening time. The average particle size of the spherical ceramic particles can be below 200 μm.

[0071] Furthermore, the average particle size of the spherical ceramic particles can be greater than 30 μm and less than 100 μm. Using spherical ceramic particles within this range enables reproducible shot peening of various untreated coatings.

[0072] The average particle size of spherical ceramic particles can be measured by laser diffraction. Alternatively, when spherical and angular ceramic particles are mixed together, the shot peening solution can be dried, and spherical ceramic particles can be extracted from SEM images. The average particle size is then calculated by taking the average equivalent circle diameter of 100 spherical ceramic particles obtained from each image.

[0073] The average roundness of the spherical ceramic particles can be 0.82 or higher. In particular, the average roundness can be 0.88 or higher. Under these conditions, the coated cutting tools manufactured exhibit high resistance to chipping. Furthermore, the upper limit for the average roundness can be 0.98.

[0074] Average roundness can be measured as follows. First, after capturing an image of the particle using SEM or TEM, use image analysis software (e.g., "Mac-View Version 4" from Mountech) to measure the particle's projected area (S) and perimeter (L). Second, substitute the obtained measurements into the formula: 4πS / L2 Calculate roundness. Roundness can be calculated for any 100 selected particles, and their average value is taken as the average roundness.

[0075] Examples of materials that can be used for spherical ceramic particles include Al₂O₃, ZrO₂, and SiC. Furthermore, using spherical ceramic particles with a higher specific gravity can reduce the average particle size, while using spherical ceramic particles with a lower specific gravity can increase the average particle size.

[0076] It can make spherical ceramic particles contain 10-40% by volume relative to water to produce shot peening fluid.

[0077] The shot peening conditions can be such that the projection pressure is 0.15–0.30 MPa and the projection time is 0.4–10.0 seconds. If the projection time exceeds 10.0 seconds, the peeling of the untreated coating is likely to increase, so it is not advisable. Furthermore, when projecting shot peening solution onto an untreated coating, at least a portion of the Al2O3 layer 10 can be preserved.

[0078] For example, coated cutting tools 1 can be manufactured using the process described above.

[0079] Furthermore, shot peening solutions can also contain angular ceramic particles. In this case, more than 50% by volume of the ceramic particles may be spherical.

[0080] Before projecting a shot peening solution containing spherical ceramic particles, a shot peening solution containing angular ceramic particles can be projected. Alternatively, after projecting a shot peening solution containing spherical ceramic particles, a shot peening solution containing angular ceramic particles can also be projected. The increased fracture toughness of coating 3 by projecting a shot peening solution containing spherical ceramic particles is difficult to decrease even when projecting a shot peening solution containing angular ceramic particles.

[0081] Furthermore, when applying shot peening liquid containing spherical ceramic particles to an untreated coating, a commercially available wet shot peening device can be used, for example.

[0082] In untreated coated cutting tools, the untreated coating can have tensile stress. Furthermore, the tensile stress is not limited to a specific value. The absolute value of the tensile stress can be set to approximately 50–500 MPa.

[0083] Untreated coatings can also exhibit compressive stress. Furthermore, compressive stress is not limited to a specific value. The absolute value of compressive stress can be set to approximately 50–2000 MPa.

[0084] Tensile and compressive stresses can be measured using the sin²ψ method with an X-ray stress measurement device (XRD). Furthermore, for residual stress measurement, the Al₂O₃ layer 10 can be measured using the (116) crystal plane of α-type Al₂O₃. The Ti-based coating 8 can be measured using the (422) crystal plane of TiCN.

[0085] In the resulting coated cutting tool 1, the area including the cutting edge 7 can be ground. This makes the area including the cutting edge 7 smooth. As a result, adhesion of the workpiece is suppressed, and the cutting edge 7 exhibits high resistance to chipping.

[0086] Furthermore, the above-described manufacturing method is one example of a method for manufacturing the coated cutting tool 1. Therefore, the coated cutting tool 1 is not limited to being manufactured by the above-described manufacturing method.

[0087] <Cutting Tools>

[0088] Next, taking the case of a coated cutting tool 1 as an example, refer to... Figure 6 The cutting tool 101 of the present invention will be described in detail for non-limiting embodiments.

[0089] Cutting tool 101, such as Figure 6 As shown in one non-limiting example, it may include: a tool holder 102 having a length from a first end 102a to a second end 102b, and having a groove 103 located on one side of the first end 102a; and a coated tool 1 located in the groove 103. When the cutting tool 101 has a coated tool 1, it can perform stable cutting operations for a long time due to the excellent chipping resistance of the coated tool 1.

[0090] The slot 103 is the part for mounting the coated tool 1. The slot 103 can have an opening on the outer peripheral surface of the tool holder 102 and the end face on the side of the first end 102a.

[0091] The coated cutting tool 1 is mounted on the retaining groove 103 such that the cutting edge 7 protrudes outward from the shank 102. Furthermore, the coated cutting tool 1 is mounted on the retaining groove 103 by a fixing screw 104. Specifically, the fixing screw 104 is inserted into the through hole 13 of the coated cutting tool 1, and the tip of the fixing screw 104 is inserted into the screw hole formed in the retaining groove 103, so that the threads are tightened together, thereby allowing the coated cutting tool 1 to be mounted in the retaining groove 103. A spacer may also be sandwiched between the coated cutting tool 1 and the retaining groove 103.

[0092] For example, steel and cast iron can be used as materials for the handle 102. When the handle 102 is made of steel, it has high toughness.

[0093] exist Figure 6In one example shown, a cutting tool 101 is illustrated for so-called turning operations. Turning operations include, for example, internal diameter machining, external diameter machining, and grooving. Furthermore, the application of the cutting tool 101 is not limited to turning operations. For example, there is no problem using the cutting tool 101 for milling operations.

[0094] The present invention will be described in detail below with examples, but the present invention is not limited to the following examples.

[0095] Example

[0096] [Samples No. 1-11]

[0097] <Making of Coated Knives>

[0098] First, the matrix is ​​prepared. Specifically, WC powder with an average particle size of 1.2 μm is mixed with 6% by mass of metallic Co powder with an average particle size of 1.5 μm, 2.0% by mass of TiC (titanium carbide) powder, and 0.2% by mass of Cr3C2 (chromium carbide) powder to prepare a mixed raw material powder. Next, the mixed raw material powder is stamped into a cutting tool shape (CNMG120408) to obtain a shaped body. The obtained shaped body is dewaxed and fired at 1400°C for 1 hour in a vacuum of 0.5–100 Pa to prepare a matrix made of cemented carbide. The rake face (first face) of the prepared matrix is ​​then subjected to honing (R-honing) by brushing.

[0099] Next, an untreated coating is formed on this substrate. Specifically, a first TiN layer, a Ti-based coating, an Al2O3 layer, and a second TiN layer are formed sequentially on the substrate, starting from the substrate side. The film formation conditions and thicknesses are as follows. Furthermore, the thicknesses are values ​​obtained by cross-sectional measurements using SEM.

[0100] (First TiN layer)

[0101] TiCl4 gas: 1.0 vol%

[0102] N2 gas: 55.0% by volume

[0103] H2 gas: Balance

[0104] Temperature: 850℃

[0105] Pressure: 16 kPa

[0106] Thickness: 1.0μm

[0107] (Ti-based coating)

[0108] TiCl4 gas: 7.0 vol%

[0109] CH3CN gas: 0.5% by volume

[0110] H2 gas: Balance

[0111] Temperature: 850℃

[0112] Pressure: 10 kPa

[0113] Thickness: 7.0μm

[0114] (Al2O3 layer)

[0115] AlCl3 gas: 4.2% by volume

[0116] HCl gas: 0.9% by volume

[0117] CO2 gas: 4.5% by volume

[0118] H2S gas: 0.3% by volume

[0119] H2 gas: Balance

[0120] Temperature: 950℃

[0121] Pressure: 9 kPa

[0122] Thickness: 8.0μm

[0123] (Second TiN layer)

[0124] TiCl4 gas: 3.0 vol%

[0125] N2 gas: 40.0% by volume

[0126] H2 gas: Balance

[0127] Temperature: 1010℃

[0128] Pressure: 30 kPa

[0129] Thickness: 2.0μm

[0130] Next, as a medium, the shot peening solution was adjusted to contain 25% by volume of water, respectively, spherical Al2O3 particles, spherical particles composed of zircon (ZrSiO4), and angular Al2O3 particles with average particle sizes shown in Table 1. Furthermore, the hardness (HV) of the medium was measured as follows.

[0131] (Medium hardness)

[0132] The hardness of the medium used in shot peening was measured by a load-unload test. First, the medium to be measured was fixed in potting resin (Kulzer Technovit 4004) and its surface was ground. Specifically, 1g of liquid curing resin and curing agent were mixed at a 3:1 (mass ratio), and 3g of Al2O3 powder was added. After mixing, the mixture was cured at room temperature (23°C) for approximately 1 hour to obtain a cured body. Then, the cured body was ground. After grinding, the hardness of the exposed portion of the cured body was measured. The measurement was performed using a dynamic microhardness tester DUH-211S. Measurements were taken under the following conditions: a 115° inter-edge angle of the measuring indenter, a diamond-tipped indenter, a test force of 49 mN, a load speed of 2.665 mN / s, and a holding time of 5 seconds. Ten measurements were taken, and the average value was calculated.

[0133] The adjusted shot peening fluid was projected onto the untreated coating at a compressed air pressure (projection pressure) of 0.2 MPa for the times shown in Table 1, resulting in a coated cutting tool. Furthermore, the shot peening fluid was projected onto the cutting areas of both the first and second surfaces. The cutting areas are those less than 1 mm from the cutting edge in the direction of the first and second surfaces.

[0134] Table 1

[0135]

[0136] <Evaluation>

[0137] For the obtained coated cutting tools, the first to fourth fracture toughness values ​​and the first to fourth hardness values ​​were measured. Additionally, the full width at half maximum (FWHM) of the (104) crystal plane in the region involved in cutting was measured. Furthermore, the obtained coated cutting tools were used for cutting evaluation to assess their resistance to chipping. The measurement methods are shown below, and the results are presented in Tables 2 and 3.

[0138] (First to fourth fracture toughness values)

[0139] For mirror-finished surfaces, indentation tests were performed using a nanoindenter. The resulting indentations were then examined using a field emission scanning electron microscope (FE-SEM) to observe cracks and measure fracture toughness. The nanoindenter used was an ENT-1100b / a ultra-micro indentation hardness tester manufactured by Elionix Corporation. The indentation load was 700 mN, and the indenter used was a Glasswell indenter ENT-20-13 manufactured by TOYO Technical Corporation. Fracture toughness values ​​were measured according to JIS R 1607:2015. Crack observation was performed using a JSM-7100F manufactured by Nippon Egis Corporation.

[0140] When the Al2O3 layer is exposed after wet shot peening, the surface of the exposed Al2O3 layer is mirror-polished, and the fracture toughness value is measured on the resulting mirror surface. If the Al2O3 layer is not exposed, mirror polishing is continued until the Al2O3 layer is exposed, and the fracture toughness value is measured on the exposed mirror surface.

[0141] The fracture toughness value of the Ti-based coating is also measured by mirror polishing the surface of the coating until the Ti-based coating is exposed, and then measuring the mirror surface of the exposed Ti-based coating.

[0142] Furthermore, in mirror polishing, a diamond polishing paste with an average particle size of 1.4 μm manufactured by TOMEI DIAMOND Co., Ltd. is used, and the concentration of the polishing paste is adjusted to 25% by mass using olive oil manufactured by Yamagata Sangyo Co., Ltd. Additionally, mirror polishing is performed in a manner that ensures the mirror surface is parallel to the surface of the substrate.

[0143] (First to fourth hardness)

[0144] Measurements were taken using a nanoindenter via an indentation test. The nanoindenter used was the ENT-1100b / a ultra-micro indentation hardness tester manufactured by Elionix Corporation. The indentation load was 700 mN, and the indenter used was the ENT-20-13 Glass indenter manufactured by TOYO Technical Corporation.

[0145] (Full width at half maximum (FWHM) of the (104) crystal plane in the region involved in the cutting)

[0146] The full width at half maximum (FWHM) of the (104) crystal plane in the area involved in cutting on the surface subjected to wet shot peening was measured. The (104) crystal plane of the Al2O3 layer was referenced to JCPDS card number 00-010-0173. When the Al2O3 layer was exposed by wet shot peening, the surface of the exposed Al2O3 layer was mirror-polished, and XRD measurements were performed on the resulting mirror surface. When the Al2O3 layer was not exposed, mirror polishing was continued until the Al2O3 layer was exposed, and XRD measurements were performed on the mirror surface where the Al2O3 layer was exposed. XRD measurements of the Al2O3 layer were performed on the surface with less surface roughness. XRD measurements were performed using a MiniFlex600 manufactured by Rigaku Corporation. The measurement conditions were as follows: the characteristic X-ray was CuKβ line, the output power was 40kV and 15mA, the emission-side Soler slit was 2.5°, the length limiting slit was 5.0mm, the divergence slit was 0.625°, the scattering slit was 8.0mm, the receiving-side Soler slit was 2.5°, the receiving slit was 13.0mm, the step size was 0.01°, the measurement speed was 2.0° / min, and the scanning angle was 20° to 90°.

[0147] (Cutting Evaluation)

[0148] Intermittent cutting tests were conducted under the following conditions.

[0149] Material to be cut: Carbon steel for mechanical structures (S45C 16-slotted steel)

[0150] Tool shape: CNMG120408

[0151] Cutting speed: 48 m / min

[0152] Feed rate: 0.27 mm / rev

[0153] Depth of cut: 1.0mm

[0154] Other: Use water-soluble cutting fluid

[0155] Evaluation item: Measure the number of impacts until collapse.

[0156] Table 2

[0157]

[0158] Table 3

[0159]

[0160] Specimen No. 1 was not treated with shot peening for its untreated coating. In other words, Specimen No. 1 is a coated tool with only a film formed on the substrate. The fracture toughness of the Ti-based coating in Specimen No. 1 is 2.6 MPa·m on both the first and second surfaces. 0.5 .

[0161] Sample No. 2 is a sample on which shot peening fluid containing angular ceramic particles was applied to both the first and second surfaces. In Sample No. 2, the fracture toughness of the Ti-based coating is improved compared to the untreated Sample No. 1, reaching 3.4 MPa·m on both the first and second surfaces. 0.5 .

[0162] Samples No. 3 and 4 are samples on which shot peening fluid containing spherical zircon (ZrSiO4) particles was applied to the first and second surfaces. In Samples No. 3 and 4, the fracture toughness of the Ti-based coating is slightly improved compared to the untreated Sample No. 1, with both the first and second surfaces showing a value of 3.3 MPa·m. 0.5 Or 4.0 MPa·m 0.5 .

[0163] The fracture toughness values ​​of the Ti-based coatings in samples No.1 to No.4 were all low.

[0164] In contrast, the Ti-based coatings of test materials No. 5 to 11, which are used as coated cutting tools of the present invention, have a fracture toughness value of 10.0 MPa·m. 0.5 or above 14.0 MPa·m 0.5 In areas with excellent resistance to breakage.

[0165] Furthermore, the average roundness was measured for spherical Al2O3 particles (samples No. 5–11) and angular Al2O3 particles (sample No. 2). Specifically, firstly, after capturing particle images using SEM, the projected area (S) and perimeter (L) of the particles were measured using image analysis software (Mountech's "Mac-View Version 4"). Secondly, the obtained measurements were substituted into the formula: 4πS / L 2 Roundness was calculated. The roundness was calculated using an arbitrary selection of 100 particles, and the average value was taken as the mean roundness. The results of the mean roundness measurement are as follows.

[0166] (Average roundness)

[0167] Spherical Al2O3 particles in samples No. 5–11: 0.90

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

[0169] Symbol Explanation

[0170] 1… Coated cutting tools

[0171] 2…Matrix

[0172] 3…coating

[0173] 4…Surface

[0174] 5…First page

[0175] 6…Second page

[0176] 7…blade

[0177] 8…Ti-based coatings

[0178] 9…Surface

[0179] 10…Al2O3 layer

[0180] 11…TiN layer (first TiN layer)

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

[0182] 13… Through hole

[0183] 101…Cutting tools

[0184] 102…handle

[0185] 102a…First end

[0186] 102b…Second end

[0187] 103…card slot

[0188] 104… Fixing screw

Claims

1. A coated cutting tool having a substrate and a coating disposed on the substrate, wherein, The coated cutting tool includes: a first surface; a second surface adjacent to the first surface; and a cutting edge located on at least a portion of the edge portion of the first surface and the second surface. The coating is a Ti-based coating containing TiCN particles. The Ti-based coating, when its fracture toughness is measured on a surface parallel to the substrate, exhibits the following characteristics: The fracture toughness value is 10 MPa·m. 0.5 The first area above; The fracture toughness value is less than 10 MPa·m. 0.5 The second area, The area less than 1 mm from the cutting edge in the direction of the first and second surfaces is the area that participates in cutting. The area that is more than 1 mm away from the cutting edge in the direction of the first and second surfaces is a region that does not participate in cutting. The first region is configured to correspond to the region involved in the cutting process. The second region is configured to correspond to the region that does not participate in cutting. The first face is the front face, and the second face is the back face.

2. The coated cutting tool according to claim 1, wherein, When the hardness of the first region is taken as the first hardness and the hardness of the second region is taken as the second hardness, the first hardness is greater than the second hardness.

3. A cutting tool, comprising: A knife handle having a length from a first end to a second end and having a groove located on the side of the first end; The coated cutting tool of claim 1 or 2 is located in the slot.

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