Coated tool and cutting tool

Abstract

A coated tool according to a non-limiting aspect of the present disclosure is cutting-tool shaped and provided with a base and a coating layer located on a surface of the base. The coating layer has a Ti-based coating layer and an Al2O3 layer. The Ti-based coating layer is in contact with the base. The Al2O3 layer is located farther from the base than the Ti-based coating layer and includes the outermost surface of the coating layer. In a blade edge ridgeline part and / or a rake face, a crack extending from the outermost surface toward the substrate is present in the coating layer. The crack is open on the outermost surface. The width of the crack from the outermost surface to -0.2 μm is 1-30 μm.

Description

Coated tools and cutting tools CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Japanese Patent Application No. 2023-086791, filed May 26, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to coated tools and cutting tools.

[0003] A coated tool (coated cemented carbide cutting tool) described in Japanese Patent Laid-Open No. 11-197907 (Patent Document 1) is known as a coated tool used in cutting tools and the like. In the cross section of the coated tool described in Patent Document 1, the average crack spacing in the coating film on the cutting edge ridge and / or rake face is smaller than the average crack spacing in the coating film on the flank. Also, the average length of cracks in the coating film on the cutting edge ridge and / or rake face is shorter than the average thickness of the coating film on the flank.

[0004] A non-limiting one-sided coated tool of the present disclosure is a coated tool in the shape of a cutting tool, including a substrate and a coating layer located on the surface of the substrate. The coating layer has a Ti-based coating layer and an Al2O3 layer. The Ti-based coating layer is in contact with the substrate. The Al2O3 layer is located farther from the substrate than the Ti-based coating layer and includes the outermost surface of the coating layer. At the cutting edge ridge and / or rake face, cracks exist in the coating layer extending from the outermost surface toward the substrate. The cracks open at the outermost surface. The width of the cracks at -0.2 μm from the outermost surface is 1 to 30 μm.

[0005] Fig. 3 is a perspective view of a non-limiting one-sided coated tool of the present disclosure. Fig. 4 is a cross-sectional view perpendicular to the surface of the substrate in the coated tool shown in Fig. 1. Fig. 5 is a plan view of the coated tool shown in Fig. 1. Fig. 6 is an enlarged view of region IV shown in Fig. 3. Fig. 7 is a perspective view of a non-limiting one-sided cutting tool of the present disclosure.

[0006] <Coated Tool> A non-limiting aspect of the coated tool 1 of the present disclosure will be described in detail below with reference to the drawings. However, for the sake of convenience, the drawings referred to below show only the main components necessary for explaining the embodiment in a simplified form. Therefore, the coated tool 1 may include any components not shown in the drawings referred to. Furthermore, the dimensions of the components in the drawings do not faithfully represent the actual dimensions of the components and the dimensional ratios of the components.

[0007] The coated tool 1 may comprise a substrate 3 and a coating layer 7 located on a surface 5 of the substrate 3, as a non-limiting example shown in FIGS.

[0008] The coated tool 1 may also have a cutting tool shape. The cutting tool shape refers to a shape that can be used as a cutting tool, and a specific configuration thereof may be a plate shape. In FIG. 1 , a cutting insert is shown as a non-limiting example of the coated tool 1. Therefore, the cutting tool shape may be rephrased as an insert shape. Note that the form of the coated tool 1 is not limited to a cutting insert.

[0009] The coated tool 1 may have a rake face 9 and a flank face 11, as in the non-limiting example shown in FIG. 1 . The coated tool 1 may also have a plate shape. For example, the coated tool 1 may have a square plate shape. The top surface may be the rake face 9. The side surface may be the flank face 11. The shape of the coated tool 1 is not limited to a square plate shape. For example, the rake face 9 (top surface) may be triangular, pentagonal, hexagonal, or circular.

[0010] The coated tool 1 is not limited to a specific size. For example, the length of one side of the rake face 9 (upper surface) may be set to about 3 to 20 mm. Also, the height from the rake face 9 (upper surface) to the surface (lower surface) located opposite the rake face 9 may be set to about 5 to 20 mm.

[0011] The coated tool 1 may have a cutting edge ridge 13 located at the intersection of the rake face 9 and the flank 11. The cutting edge ridge 13 may be a portion of the intersection of the rake face 9 and the flank 11 that has been subjected to cutting edge treatment. The cutting edge ridge 13 may be located over the entire intersection of the rake face 9 and the flank 11, or may be located over only a portion of this intersection. The cutting edge ridge 13 can be used to cut a workpiece when manufacturing a machined product using the coated tool 1. The cutting edge ridge 13 may also be referred to as a cutting edge.

[0012] As a non-limiting example shown in FIG. 2, the coating layer 7 may include a Ti-based coating layer 15 (titanium-based coating layer) and an Al2O3 layer 17 (alumina layer).

[0013] The Ti-based coating layer 15 may be in contact with the substrate 3. The Ti-based coating layer 15 may also be called an underlayer.

[0014] The Al2O3 layer 17 may be located farther from the substrate 3 than the Ti-based coating layer 15. Alternatively, the Al2O3 layer 17 may be located farthest from the substrate 3 in the coating layer 7. The Al2O3 layer 17 may include the outermost surface 19 of the coating layer 7. In other words, the Al2O3 layer 17 may be the outermost layer.

[0015] Here, in the cutting edge ridge 13 and / or the rake face 9, cracks 21 may be present in the coating layer 7 extending from the outermost surface 19 toward the substrate 3 (see FIG. 2). The cracks 21 may also open at the outermost surface 19 (see FIGS. 2 and 4). The width W of the cracks 21 at −0.2 μm from the outermost surface 19 may be 1 to 30 μm. In other words, in a region R within a range of −0.2 μm from the outermost surface 19, the width W of the cracks 21 may be 1 to 30 μm. The “−” (minus sign) in “−0.2 μm” means that the value approaches the substrate 3.

[0016] When the cracks 21 that open to the outermost surface 19 exist in the cutting edge ridge 13 and / or the rake face 9 and the width W of the cracks 21 at and near the outermost surface 19 is large as described above, the toughness of the coating layer 7 (AlO layer 17) is likely to be improved. Therefore, the coated tool 1 has high chipping resistance and fracture resistance.

[0017] A plurality of cracks 21 may be present in the coating layer 7 at the cutting edge ridge 13 and / or the rake face 9. The plurality of cracks 21 may also be open at the outermost surface 19. The cracks 21 may also be referred to as fissures.

[0018] The width W of the crack 21 may be measured by observing the outermost surface 19 using a laser microscope. Furthermore, when a plurality of cracks 21 open on the outermost surface 19, the width W of the crack 21 may be an average value. Specifically, the width W of the crack 21 may be an average value measured under the conditions of taking a photo of the outermost surface 19 using a laser microscope at a magnification of 500 times, defining a 205 μm × 275 μm range as one field of view, measuring the width W of the crack 21 present in the one field of view at five measurement points spaced at intervals of 0.13 μm or 0.26 μm in a direction perpendicular to the extension direction of the crack 21 (direction A shown in FIG. 4 ), and taking three photographic locations. Examples of the laser microscope include the VK-X1000 series manufactured by KEYENCE Corporation.

[0019] The maximum value of the width W of the crack 21 may be present at the outermost surface 19 (see FIG. 2). The width W of the crack 21 may decrease with increasing distance from the outermost surface 19. The width W of the crack 21 may be 2 to 30 μm. The width W of the crack 21 may be 6 to 30 μm.

[0020] Region R may be located closer to the outermost surface 19 than the center 17a in the thickness direction of the Al2O3 layer 17. In this case, the strength of the Al2O3 layer 17 is easily ensured. Also, the toughness of the Al2O3 layer 17 is easily improved. Note that the entire crack 21 may be located closer to the outermost surface 19 than the center 17a in the thickness direction of the Al2O3 layer 17.

[0021] The area ratio of the cracks 21 on the outermost surface 19 may be 5 to 30%. In this case, it is easy to avoid an excessively large proportion of cracks 21 opening on the outermost surface 19. In other words, the strength of the outermost surface 19 is easy to ensure. Therefore, chipping resistance and fracture resistance are easy to improve. The lower limit of the area ratio of the cracks 21 may be 6%. The upper limit of the area ratio of the cracks 21 may be 26%.

[0022] The area ratio of cracks 21 on the outermost surface 19 can be evaluated using a laser microscope to obtain an image of the outermost surface 19, with height data measured over a 205 μm × 275 μm area at 500x magnification, as one field of view. In the image, the average value of the height data is taken as the reference plane (zero point), and the surface area of ​​the region that is −0.2 μm or less from the reference plane is S, and the total measured area (the entire area of ​​the image) is ST, and the value may be calculated from the formula: (S / ST) × 100. The “−” (minus sign) in “−0.2 μm” means that the value is closer to the substrate 3.

[0023] The depth D of the opened crack 21 may be 0.3 to 5 μm (see FIG. 2). In this case, chipping resistance and fracture resistance are likely to be improved. The lower limit of the depth D of the crack 21 may be 0.4 μm. The upper limit of the depth D of the crack 21 may be 1.9 μm.

[0024] The depth D of the opened crack 21 may be measured by observing the outermost surface 19 using a laser microscope. When a plurality of cracks 21 open on the outermost surface 19, the depth D of the opened cracks 21 may be an average value. Specifically, the depth D of the opened crack 21 may be an average value of the measured values ​​of 15 cracks (= 5 cracks × 3 locations) measured under the condition that five cracks 21 present within an area of ​​205 μm × 275 μm in a micrograph obtained by photographing the outermost surface 19 at a magnification of 500 times using a laser microscope are measured, and the photographing locations are three.

[0025] In the cutting edge ridge 13 and / or the rake face 9, a plurality of regions 23 surrounded by cracks 21 may be present on the outermost surface 19 (see FIG. 3). In this case, the strength of the outermost surface 19 is likely to be ensured by the plurality of regions 23. The area ratio of the cracks 21 is likely to be 5 to 30%. The region 23 may be composed of a plurality of cracks 21. The presence of the region 23 on the outermost surface 19 may be confirmed by observing the outermost surface 19 using, for example, a metallurgical microscope.

[0026] The substrate 3 may be a sintered alloy. The sintered alloy may be made of a cemented carbide. In other words, the substrate 3 may be made of a cemented carbide. The cemented carbide may contain a hard phase and a binder phase. The hard phase in the cemented carbide may contain, for example, tungsten carbide (WC). Furthermore, the hard phase in the cemented carbide may contain WC as the main component. In other words, the cemented carbide may be a WC-based cemented carbide. The "main component" refers to the component that has the largest mass percentage compared to other components.

[0027] The binder phase in the cemented carbide may contain an iron group metal. Examples of iron group metals include cobalt (Co) and nickel (Ni). The binder phase in the cemented carbide may contain at least one of Co and Ni. The binder phase in the cemented carbide may contain an iron group metal as a main component. The binder phase may function as a phase that bonds adjacent hard phases.

[0028] The substrate 3 may be made of a cemented carbide. In this case, the hard phase may be made of WC. Alternatively, the hard phase may contain a cubic crystal structure compound in addition to WC. In this case, the cubic crystal structure compound may be composed of at least one selected from carbides, nitrides, carbonates, nitrides, and mutual solid solutions of elements in Groups 4, 5, and 6 of the periodic table. That is, the hard phase may be composed of WC and at least one cubic crystal structure compound selected from carbides, nitrides, carbonates, nitrides, and mutual solid solutions of elements in Groups 4, 5, and 6 of the periodic table. Alternatively, the binder phase may be mainly composed of Co and / or Ni.

[0029] When the substrate 3 is a sintered alloy, the sintered alloy may be made of a cermet. In other words, the substrate 3 may be made of a cermet. The cermet may contain a hard phase and a binder phase. The hard phase in the cermet may contain, for example, a titanium (Ti) compound. Examples of Ti compounds include titanium carbonitride (TiCN), titanium carbide (TiC), and titanium nitride (TiN). The hard phase in the cermet may also contain a Ti compound as a main component. That is, the cermet may be a Ti-based cermet.

[0030] The binder phase in the cermet may contain an iron group metal. The binder phase in the cermet may contain at least one of Co and Ni. The binder phase in the cermet may contain an iron group metal as a main component.

[0031] The composition of the substrate 3 may be measured by, for example, energy dispersive X-ray spectroscopy (EDS). The measurement may be performed using an EDS attached to an electron microscope. Examples of electron microscopes include a scanning electron microscope (SEM) and a transmission electron microscope (TEM).

[0032] The Ti-based coating layer 15 may be a single layer. The composition of the Ti-based coating layer 15 may include, for example, TiN. The Ti-based coating layer 15 may be a TiN layer.

[0033] The coating layer 7 is not limited to a specific thickness. For example, the Ti-based coating layer 15 may have an average thickness of 0.1 to 1 μm, and the AlO layer 17 may have an average thickness of 1 to 15 μm.

[0034] The average thickness of the coating layer 7 may be measured by cross-sectional observation using an electron microscope. Specifically, the average thickness of the coating layer 7 may be measured in a 40 μm × 50 μm area of ​​a micrograph obtained by photographing a cross section perpendicular to the surface 5 of the substrate 3 using an electron microscope at a magnification of 3000 times, and the thickness of the object to be measured, such as the Ti-based coating layer 15, is measured at five measurement points at 5 μm intervals along a direction perpendicular to the thickness direction of the coating layer 7, with the total number of photographed points being three. Note that the average thickness of the coating layer 7 does not need to be measured at multiple cross sections; it is sufficient to measure it at one cross section.

[0035] 2, the coating layer 7 may include, in order from the substrate 3, a Ti-based coating layer 15, a first TiCN layer 25, a second TiCN layer 27, a TiCNO layer 29 (titanium carbonate nitride layer), and an Al2O3 layer 17. In this case, the life of the coated tool 1 is likely to be extended.

[0036] The first TiCN layer 25 may be a so-called MT (moderate temperature) TiCN layer. The first TiCN layer 25 may have an average thickness of 2 to 15 μm. In this case, the first TiCN layer 25 has high wear resistance and chipping resistance. The titanium carbonitride crystals contained in the first TiCN layer 25 may be columnar crystals elongated in the thickness direction of the coating layer 7. The first TiCN layer 25 may be in contact with the Ti-based coating layer 15.

[0037] The second TiCN layer 27 may be a so-called HT (high temperature)-TiCN layer. The second TiCN layer 27 may have an average thickness of 10 to 900 nm. The second TiCN layer 27 may be in contact with the first TiCN layer 25.

[0038] The average thickness of the TiCNO layer 29 may be set to 200 to 2000 nm, which is likely to improve adhesion to the Al2O3 layer 17. The TiCNO layer 29 may be in contact with the second TiCN layer 27.

[0039] The average thickness of the Al 2 O 3 layer 17 may be greater than the average thickness of the TiCNO layer 29. The Al 2 O 3 layer 17 may be in contact with the TiCNO layer 29.

[0040] The coating layer 7 may further include a TiCN layer located between the Ti-based coating layer 15 and the Al2O3 layer 17. The residual stress of the Al2O3 layer 17 may be 100 to 250 MPa. The residual stress of the TiCN layer may be 150 to 300 MPa. In these cases, the chipping resistance is likely to be improved. The TiCN layer may be a first TiCN layer 25 (MT-TiCN layer).

[0041] When the residual stress value is positive (+), the residual stress is tensile stress. When the residual stress value is negative (-), the residual stress is compressive stress. Residual stress may be measured by, for example, the sin2ψ method using an X-ray stress measurement device (X-ray Diffraction: XRD).

[0042] The measurement conditions for residual stress may be set, for example, as follows: Radiation source: CuK Output: 50 kV, 1000 μA Collimator diameter: 0.5 mmφ Measurement method: sin2ψ method Other: Measurement is performed with n=3, and the average value is calculated.

[0043] The coating layer 7 may be located on the entire surface 5 of the base 3, or may be located on only a portion thereof. That is, the coating layer 7 may be located on at least a portion of the surface 5 of the base 3 (a portion corresponding to the cutting edge ridge 13 and / or the rake face 9).

[0044] The coating layer 7 may be formed by a chemical vapor deposition (CVD) method. In other words, the coating layer 7 may be a CVD film. Note that the coating layer 7 may also be a physical vapor deposition (PVD) film formed by a PVD method.

[0045] The coated tool 1 may have a through hole 31. The through hole 31 can be used to attach a screw, a clamp member, or the like when fixing the coated tool 1 to a holder. The through hole 31 may be formed from the rake face 9 (upper surface) to the surface (lower surface) located opposite the rake face 9, or may open in these surfaces. Note that there is no problem even if the through holes 31 are configured to open in opposing regions of the flank face 11 (side surface).

[0046] <Method for Manufacturing a Coated Tool> Next, a method for manufacturing a non-limiting one-sided coated tool according to the present disclosure will be described.

[0047] When manufacturing a coated tool, a substrate may be prepared first. An example of preparing a substrate made of a sintered alloy will be described below. First, a mixed powder may be obtained by adding metal powder, carbon powder, etc. to an inorganic powder such as a carbide, nitride, carbonitride, or oxide that can be fired to form a substrate, and mixing the powder. This mixed powder may then be molded into a desired cutting tool shape by a known molding method, such as press molding, slip casting, extrusion molding, or cold isostatic pressing. The resulting molded body may then be fired in a vacuum or a non-oxidizing atmosphere to obtain a substrate made of a sintered alloy.

[0048] Next, a coating layer may be formed on the surface of the obtained substrate by a CVD method. The conditions for forming each layer will be described below in order, taking as an example a case where the coating layer has, from the substrate side, a Ti-based coating layer, a first TiCN layer (MT-TiCN layer), a second TiCN layer (HT-TiCN layer), a TiCNO layer, and an Al2O3 layer.

[0049] When depositing a TiN layer as a Ti-based coating layer, a mixed gas containing 0.5 to 10 volume % titanium tetrachloride (TiCl4) gas, 10 to 60 volume % nitrogen (N2) gas, and the remainder hydrogen (H2) gas may be prepared as a reaction gas composition. This mixed gas may then be introduced into a chamber, and the deposition temperature may be set to 800 to 940°C and the pressure may be set to 8 to 50 kPa to deposit the TiN layer.

[0050] The first TiCN layer (MT-TiCN layer) may be formed as follows. First, a mixed gas containing 0.5 to 10 volume percent titanium tetrachloride (TiCl) gas, 5 to 60 volume percent nitrogen (N), 0.1 to 3 volume percent acetonitrile (CHCN), and the remainder hydrogen (H) gas may be prepared as the reaction gas composition. This mixed gas may then be introduced into a chamber, and the film formation temperature may be set to a relatively low temperature of 780 to 880°C, and the pressure may be set to 5 to 25 kPa, to form the first TiCN layer. If the content of acetonitrile (CHCN) gas is increased in the later stage of film formation compared to the early stage, the average crystal width of the columnar titanium carbonitride crystals constituting the first TiCN layer is likely to be larger on the outermost surface side than on the substrate side.

[0051] The second TiCN layer (HT-TiCN layer) may be formed as follows. First, a mixed gas containing 1 to 4 volume percent titanium tetrachloride (TiCl4) gas, 5 to 20 volume percent nitrogen (N2) gas, 0.1 to 10 volume percent methane (CH4) gas, and the remainder hydrogen (H2) gas may be prepared as the reaction gas composition. Then, this mixed gas may be introduced into a chamber, and the second TiCN layer may be formed at a film formation temperature of 900 to 990°C and a pressure of 5 to 40 kPa. The second TiCN layer may be formed at a higher temperature than the first TiCN layer.

[0052] The TiCNO layer may be formed as follows. First, a mixed gas containing 3 to 15 volume percent titanium tetrachloride (TiCl4) gas, 3 to 50 volume percent nitrogen (N2) gas, 0.5 to 15 volume percent methane (CH4) gas, 0.5 to 10 volume percent carbon monoxide (CO) gas, and the remainder hydrogen (H2) gas may be prepared as the reaction gas composition. This mixed gas may then be introduced into a chamber, and the film formation temperature may be set to 900 to 1010°C and the pressure may be set to 5 to 40 kPa to form the TiCNO layer.

[0053] The Al2O3 layer may be formed as follows. First, a mixed gas containing 3.5 to 15 volume percent aluminum trichloride (AlCl3) gas, 0.5 to 2.5 volume percent hydrogen chloride (HCl) gas, 0.5 to 5 volume percent carbon dioxide (CO2) gas, 0 to 1 volume percent hydrogen sulfide (HS) gas, and the remainder hydrogen (H2) gas may be prepared as the reaction gas composition. Then, this mixed gas may be introduced into a chamber, and the Al2O3 layer may be formed at a film formation temperature of 900 to 1010°C and a pressure of 5 to 20 kPa.

[0054] The coated tool may be obtained by subjecting the formed coating layer to a surface treatment for forming cracks on the cutting edge and / or the rake face. The surface treatment may include a first treatment and a second treatment.

[0055] The first treatment uses media having an average particle size of 30 to 70 μm and is performed at an air pressure of 0.2 to 0.5 MPa for 1 to 20 seconds. This first treatment may be performed as a pretreatment for forming cracks. The first treatment may also be performed for the purpose of alleviating residual tensile stress in the first TiCN layer (MT-TiCN layer). The average particle size of the media may be a value measured by laser diffraction. Examples of the first treatment include treatments 1-1 to 1-3 shown below.

[0056] (1st-1st process) Media: average particle size 50 μm Air pressure: 0.3 MPa Processing time: 10 seconds (1st-2nd process) Media: average particle size 50 μm Air pressure: 0.4 MPa Processing time: 10 seconds (1st-3rd process) Media: average particle size 50 μm Air pressure: 0.5 MPa Processing time: 10 seconds

[0057] The second treatment is carried out after the first treatment, using media having an average particle size of 10 μm or more and less than 50 μm, at an air pressure of 0.2 to 0.5 MPa for 0.1 to 20 seconds. Examples of the second treatment include the following treatments 2-1 to 2-3.

[0058] (2nd-1st process) Media: Average particle size 35 μm Air pressure: 0.25 MPa Processing time: 0.5 s (2nd-2nd process) Media: Average particle size 35 μm Air pressure: 0.25 MPa Processing time: 2 s (2nd-3rd process) Media: Average particle size 35 μm Air pressure: 0.25 MPa Processing time: 10 s

[0059] The first and second processes exemplified above are performed in any of the following combinations (1) to (5): (1) Process 1-3 and Process 2-1 (2) Process 1-1 and Process 2-2 (3) Process 1-2 and Process 2-2 (4) Process 1-1 and Process 2-3 (5) Process 1-3 and Process 2-2

[0060] When the first treatment and the second treatment are performed in a combination of the above (1) to (5), cracks extending from the outermost surface toward the substrate are likely to form in the coating layer during the second treatment. Furthermore, the cracks are likely to open at the outermost surface. The width of the cracks at -0.2 μm from the outermost surface is likely to be 1 to 30 μm. The area ratio of the cracks at the outermost surface is likely to be 5 to 30%. The depth of the cracks is likely to be 0.3 to 5 μm. With only the first treatment, cracks having the above configuration are unlikely to form. With only the second treatment, cracks having the above configuration are unlikely to form.

[0061] When the first and second treatments are performed using a combination of the above (2) to (5), the residual stress of the Al2O3 layer tends to be 100 to 250 MPa, and the residual stress of the TiCN layer tends to be 150 to 300 MPa.

[0062] The above-described manufacturing method is merely an example of a method for manufacturing a coated tool, and it goes without saying that the coated tool is not limited to one manufactured by the above-described manufacturing method.

[0063] <Cutting Tool> Next, a non-limiting one-sided cutting tool 101 of the present disclosure will be described with reference to the drawings, taking as an example a case where the cutting tool 1 is provided with the above-described coated tool 1 .

[0064] 5 , the cutting tool 101 may include a holder 103 and a coated tool 1. The holder 103 may extend from a first end 103a to a second end 103b and may have a pocket 105 on the side of the first end 103a. The coated tool 1 may be located in the pocket 105. When the cutting tool 101 includes the coated tool 1, stable cutting is possible due to the high chipping resistance and fracture resistance of the coated tool 1.

[0065] The pocket 105 may be a portion to which the coated tool 1 is attached. The pocket 105 may be open at the outer peripheral surface of the holder 103 and at the end surface on the side of the first end 103a.

[0066] The coated tool 1 may be attached to the pocket 105 so that at least a part of the cutting edge ridge 13 protrudes from the holder 103. Alternatively, the coated tool 1 may be attached to the pocket 105 by a screw 107. That is, the coated tool 1 may be attached to the pocket 105 by inserting the screw 107 into the through hole 31 of the coated tool 1 and inserting the tip of the screw 107 into a threaded hole formed in the pocket 105 to fix the screw 107 in the threaded hole. At this time, the lower surface of the coated tool 1 may be in direct contact with the pocket 105, or a sheet may be sandwiched between the coated tool 1 and the pocket 105.

[0067] Examples of materials for the holder 103 include steel and cast iron. When the material for the holder 103 is steel, the holder 103 has high toughness.

[0068] 5 illustrates a cutting tool 101 used for so-called turning. Examples of turning include inner diameter machining, outer diameter machining, and grooving. The cutting tool 101 (coated tool 1) is not limited to use for turning. For example, there is no problem in using the coated tool 1 for a cutting tool 101 used for milling.

[0069] The above has provided examples of the non-limiting one-sided coated tool 1 and cutting tool 101 of the present disclosure, but it goes without saying that the present disclosure is not limited to the above-mentioned embodiments and can be any as long as it does not deviate from the gist of the present disclosure.

[0070] For example, the coated tool 1 and cutting tool 101 may have the following configurations. (1) The coated tool is a cutting tool-shaped coated tool including a substrate and a coating layer located on the surface of the substrate, the coating layer having a Ti-based coating layer and an Al2O3 layer, the Ti-based coating layer being in contact with the substrate, the Al2O3 layer being located farther from the substrate than the Ti-based coating layer, and including an outermost surface of the coating layer, and at the cutting edge ridge and / or rake face, cracks are present in the coating layer extending from the outermost surface toward the substrate, the cracks open at the outermost surface, and the width of the cracks at a distance of -0.2 μm from the outermost surface is 1 to 30 μm. (2) In the coated tool described in (1) above, the area ratio of the cracks on the outermost surface may be 5 to 30%. (3) In the coated tool described in (1) or (2) above, the depth of the cracks may be 0.3 to 5 μm. (4) In the coated tool of any one of (1) to (3) above, the substrate may be a sintered alloy made of cemented carbide or cermet containing a hard phase and a binder phase. (5) In the coated tool of any one of (1) to (3) above, the substrate may be made of cemented carbide containing a hard phase and a binder phase, the hard phase may be made of tungsten carbide and at least one cubic crystal structure compound selected from carbides, nitrides, carbonates, oxynitrides of elements in Groups 4, 5, and 6 of the Periodic Table and their mutual solid solutions, and the binder phase may be mainly composed of cobalt and / or nickel. (6) In the coated tool of any one of (1) to (5) above, the coating layer may have, in order from the substrate, the Ti-based coating layer, a first TiCN layer, a second TiCN layer, a TiCNO layer, and the Al2O3 layer. (7) In the coated tool of any one of (1) to (5) above, the coating layer may further include a TiCN layer located between the Ti-based coating layer and the Al2O3 layer, and the Al2O3 layer may have a residual stress of 100 to 250 MPa, and the TiCN layer may have a residual stress of 150 to 300 MPa. (8) A cutting tool may include a holder extending from a first end to a second end and having a pocket on the side of the first end, and the coated tool of any one of (1) to (7) above located in the pocket.

[0071] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to the following examples.

[0072] [Samples No. 1 to 9] <Preparation of Coated Tools> First, a substrate was prepared. Specifically, a mixed powder was obtained by mixing 6 mass% of metallic cobalt powder having an average particle size of 1.2 μm, 0.5 mass% of titanium carbide powder having an average particle size of 2 μm, 5 mass% of niobium carbide powder having an average particle size of 2 μm, and the remainder, tungsten carbide powder having an average particle size of 1.5 μm. The average particle size of each powder was measured by the Microtrac method.

[0073] The resulting mixed powder was then press-molded into a cutting tool shape (CNMG120408) to obtain a compact. The resulting compact was then subjected to a binder removal treatment and fired in a non-oxidizing atmosphere to obtain a substrate made of cemented carbide. The firing temperature was set to 1450°C, the firing time was set to 1 hour, and an argon atmosphere was used as the non-oxidizing atmosphere.

[0074] The composition of the obtained cemented carbide was measured by EDS. Specifically, cross-section observation was performed using an EDS attached to an SEM, with a magnification of 5,000 to 20,000 times, and the average value of measurements at five locations was measured. Five elements, namely, tungsten carbide, cobalt, titanium, carbon, and nitrogen, were selected for measurement by EDS.

[0075] The EDS measurement results showed that the obtained cemented carbide contained a hard phase and a binder phase. More specifically, the obtained cemented carbide contained a hard phase made of WC and a binder phase mainly composed of Co.

[0076] Next, a coating layer was formed on the surface of the obtained substrate by CVD. The formed coating layer on the rake face was then subjected to the surface treatment shown in Table 1 to obtain the coated tool samples shown in Table 1.

[0077] The samples shown in Table 1 were prepared by first forming a Ti-based coating layer on the surface of a substrate, and then forming a first TiCN layer (MT-TiCN layer), a second TiCN layer (HT-TiCN layer), a TiCNO layer, and an Al2O3 layer on the Ti-based coating layer in this order. The respective film formation conditions were as follows:

[0078] (Deposition conditions for Ti-based coating layer) A single layer of TiN was deposited as the Ti-based coating layer. First, a mixed gas consisting of 1 volume % titanium tetrachloride (TiCl4) gas, 38 volume % nitrogen (N2) gas, and the remainder hydrogen (H2) gas was prepared as the reaction gas composition. This mixed gas was then introduced into a chamber, and the deposition temperature and pressure were set to 850°C and 16 kPa, respectively. The deposition time was set to 180 minutes.

[0079] (Film formation conditions for the first TiCN layer (MT-TiCN layer)) First, a mixed gas consisting of 4 vol% titanium tetrachloride (TiCl4) gas, 23 vol% nitrogen (N2) gas, 0.4 vol% acetonitrile (CH3CN) gas, and the remainder hydrogen (H2) gas was prepared as the reaction gas composition. This mixed gas was then introduced into the chamber, and the film formation temperature was set to 850°C and the pressure to 9 kPa. The film formation time was set to 400 minutes.

[0080] (Film formation conditions for the second TiCN layer (HT-TiCN layer)) First, a mixed gas consisting of 4 volume % titanium tetrachloride (TiCl4) gas, 20 volume % nitrogen (N2) gas, 8 volume % methane (CH4) gas, and the remainder hydrogen (H2) gas was prepared as the reaction gas composition. This mixed gas was then introduced into the chamber, and the film formation temperature was set to 950°C and the pressure to 13 kPa. The film formation time was set to 80 minutes.

[0081] (Film formation conditions for TiCNO layer) First, a mixed gas containing 4 vol% titanium tetrachloride (TiCl4) gas, 20 vol% nitrogen (N2) gas, 8 vol% methane (CH4) gas, 2 vol% carbon monoxide (CO) gas, and the remainder hydrogen (H2) gas was prepared as the reaction gas composition. This mixed gas was then introduced into a chamber, and the film formation temperature and pressure were set to 950°C and 10 kPa, respectively. The film formation time was set to 30 minutes.

[0082] (Al2O3 Layer Deposition Conditions) First, a mixed gas containing 3.7 vol% aluminum trichloride (AlCl3) gas, 0.7 vol% hydrogen chloride (HCl) gas, 4.3 vol% carbon dioxide (CO2) gas, 0.3 vol% hydrogen sulfide (HS) gas, and the remainder hydrogen (H2) gas was prepared as the reaction gas composition. This mixed gas was then introduced into a chamber, and the deposition temperature and pressure were set to 950°C and 7.5 kPa, respectively. The deposition time was set to 380 minutes.

[0083] The surface treatment was performed under the following conditions. The conditions for the first treatment were as follows: (1-1 treatment) Media: average particle size 50 μm Air pressure: 0.3 MPa Treatment time: 10 s (1-2 treatment) Media: average particle size 50 μm Air pressure: 0.4 MPa Treatment time: 10 s (1-3 treatment) Media: average particle size 50 μm Air pressure: 0.5 MPa Treatment time: 10 s

[0084] The conditions for the second treatment were as follows: (2-1 treatment) Media: average particle size 35 μm Air pressure: 0.25 MPa Treatment time: 0.5 s (2-2 treatment) Media: average particle size 35 μm Air pressure: 0.25 MPa Treatment time: 2 s (2-3 treatment) Media: average particle size 35 μm Air pressure: 0.25 MPa Treatment time: 10 s

[0085] The average particle size of each medium is a value measured by laser diffraction.

[0086] For the obtained coated tool, the width of cracks at a distance of -0.2 μm from the outermost surface was measured according to the method exemplified above. Specifically, on the rake face, a laser microscope was used to photograph the outermost surface at 500x magnification, and a 205 μm × 275 μm area in the obtained micrograph was defined as one field of view. Furthermore, the width of cracks present in the one field of view was measured at five measurement points spaced 0.13 μm apart in a direction perpendicular to the direction of crack extension. An average value was then measured under the condition that three photographing points were used. The measurement results are shown in the "Width (μm)" column under "Crack" in Table 1. The laser microscope used was a VK-X1000 manufactured by KEYENCE Corporation.

[0087] The depth of the opened cracks was measured according to the method exemplified above. Specifically, on the rake face, five cracks present within a 205 μm × 275 μm area in a micrograph obtained by photographing the outermost surface at 500 times magnification using a laser microscope were measured, and the average value was calculated from the measured values ​​of 15 cracks (= 5 cracks × 3 locations) measured under the condition that the photographing locations were three. The measurement results are shown in the "Depth (μm)" column of "Crack" in Table 1.

[0088] The area ratio of cracks on the outermost surface was measured according to the method exemplified above. Specifically, the rake face was evaluated using an image in which height data measured on the outermost surface at 500x magnification over a range of 205 μm × 275 μm was used as one field of view. In the image, the average value of the height data was taken as the reference surface (zero point), and the surface area of ​​the region −0.2 μm or less from the reference surface was defined as S, and the total measured area (the entire area of ​​the image) was defined as ST. The area ratio was calculated from the formula: (S / ST) × 100. The measurement results are shown in the “Area Ratio (%)” column under “Cracks” in Table 1.

[0089] In Samples Nos. 1 to 7, a plurality of open cracks were present on the outermost surface of the rake face. Furthermore, the conditions shown in Figures 2 to 4 were confirmed in Samples Nos. 1 to 5. On the other hand, in Samples Nos. 8 and 9, no open cracks were present on the outermost surface of the rake face.

[0090] The presence of regions on the outermost surface of the rake face was confirmed using a metallurgical microscope. As a result, in Samples No. 1 to 5, multiple regions surrounded by cracks were present on the outermost surface of the rake face. The regions were composed of multiple cracks.

[0091] The residual stress of the Al2O3 layer and the first TiCN layer (MT-TiCN layer) of the obtained coated tool was measured according to the method exemplified above. The measurement results are shown in the "Residual stress (MPa)" column of Table 1.

[0092] <Evaluation> The coated tools thus obtained were subjected to a cutting test, specifically, chipping evaluation and fracture evaluation under the following conditions.

[0093] (Chipping evaluation) Machining method: turning Cutting speed: 250 m / min Feed: 0.3 mm / rev Depth of cut: 1.5 mm Workpiece: SUJ2 φ150 round bar Machining condition: WET

[0094] (Damage evaluation) Machining method: Turning Cutting speed: 50 m / min Feed: 0.2 mm / rev Depth of cut: 1 mm Workpiece: S45C φ200 round bar Machining condition: WET

[0095] The test results are shown in Table 1. In Table 1, "Cutting time (min) until chipping occurs" refers to the time when the coating layer peels off and the exposed width of the substrate reaches 0.2 mm in the chipping evaluation. Also, "Number of impacts until fracture" refers to the number of impacts until the cutting edge fractures in the fracture evaluation.

[0096]

[0097] Compared with samples Nos. 6 to 9, samples Nos. 1 to 5 exhibited higher chipping resistance and fracture resistance.

[0098] Coated tools were produced under the same conditions as Samples No. 1 to 9, except that the coating layer on the cutting edge ridge instead of the rake face was subjected to the surface treatment shown in Table 1, and the width, depth, and area ratio of cracks at a distance of −0.2 μm from the outermost surface were measured under the same conditions as Samples No. 1 to 9. As a result, the cutting edge ridge of each sample showed substantially the same measurement results as the rake face.

[0099] DESCRIPTION OF SYMBOLS 1... Coated tool 3... Base body 5... Surface 7... Coating layer 9... Rake face (upper surface) 11... Flank face (side surface) 13... Cutting edge ridge 15... Ti-based coating layer 17... Al2O3 layer 19... Outermost surface 21... Crack 23... Region 25... First TiCN layer 27... Second TiCN layer 29... TiCNO layer 31... Through hole 101... Cutting tool 103... Holder 103a... First end 103b... Second end 105... Pocket 107... Screw

Claims

1. a substrate; a coating layer located on a surface of the substrate, The coating layer is a Ti-based coating layer and an Al ２ O ３ a layer; the Ti-based coating layer is in contact with the substrate, The Al ２ O ３ a layer located farther from the substrate than the Ti-based coating layer and including the outermost surface of the coating layer, At the cutting edge ridge and / or the rake face, cracks extending from the outermost surface toward the substrate are present in the coating layer, the crack opens at the outermost surface, The coated tool has a width of the crack at a position −0.2 μm from the outermost surface of 1 to 30 μm.

2. 2. The coated tool according to claim 1, wherein an area ratio of the cracks on the outermost surface is 5 to 30%.

3. 3. The coated tool according to claim 1, wherein the cracks have a depth of 0.3 to 5 μm.

4. 3. The coated tool according to claim 1, wherein the substrate is a sintered alloy made of cemented carbide or cermet containing a hard phase and a binder phase.

5. the substrate is made of a cemented carbide containing a hard phase and a binder phase, the hard phase comprises tungsten carbide or tungsten carbide and at least one cubic crystal structure compound selected from the group consisting of carbides, nitrides, carbonates, oxynitrides of elements in Groups 4, 5 and 6 of the Periodic Table, and their mutual solid solutions; 3. The coated tool according to claim 1, wherein the binder phase is based on cobalt and / or nickel.

6. The coating layer is made up of, in order from the substrate, the Ti-based coating layer, the first TiCN layer, the second TiCN layer, the TiCNO layer, and the Al ２ O ３ 3. The coated tool according to claim 1, having a layer.

7. The coating layer is made of the Ti-based coating layer and the Al ２ O ３ further comprising a TiCN layer positioned between the layers; The Al ２ O ３ 3. The coated tool according to claim 1, wherein the layer has a residual stress of 100 to 250 MPa and the TiCN layer has a residual stress of 150 to 300 MPa.

8. a holder extending from a first end to a second end and having a pocket on the side of the first end; A cutting tool comprising: the coated tool according to claim 1 or 2 located in the pocket.