Coated tool and cutting tool

Abstract

A non-limited coated cutting tool of the present invention is a coated cutting tool provided with a base body and a coating layer on the surface of the base body. The coating layer has a Ti-based coating layer. The Ti-based coating layer is in contact with the substrate. The substrate has a crack extending from the surface toward an interior of the substrate. A portion of the Ti-based coating layer is present in the crack.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of Japanese Patent Application No. 2023 - 031807 filed on March 2, 2023, and the entire disclosure of the prior application is incorporated herein by reference. Technical field

[0003] The present invention relates to a coated cutting tool and a cutting tool. Background art

[0004] As a coated cutting tool for a cutting tool or the like, for example, a coated cutting tool (surface - coated sintered alloy) described in Japanese Patent No. 4043145 (Patent Document 1) is known. In the coated cutting tool described in Patent Document 1, a hard film is coated on the surface of the base material. In the hard film, a diffusion - element - containing layer in which a ferrous metal and tungsten are diffused is formed. Summary of the invention

[0005] A non - limiting coated cutting tool of the present invention is a coated cutting tool having a substrate and a coating on the surface of the substrate. The coating has a Ti - based film layer. The Ti - based film layer is in contact with the substrate. The substrate has a crack extending from the surface toward the inside of the substrate. A part of the Ti - based film layer exists in the crack. Brief description of the drawings

[0006] Figure 1 is a perspective view showing a non - limiting coated cutting tool of the present invention.

[0007] Figure 2 is Figure 1 a cross - sectional view orthogonal to the surface of the substrate in the shown coated cutting tool.

[0008] Figure 3 is an enlarged Figure 2 view of the vicinity of the boundary between the shown substrate and the Ti - based film layer.

[0009] Figure 4 is a perspective view showing a non - limiting cutting tool of the present invention. Detailed description of the invention

[0010] <Coated cutting tool>

[0011] Hereinafter, a non - limiting coated cutting tool 1 of the present invention will be described in detail with reference to the drawings. However, in each of the drawings referred to below, for the sake of convenience of explanation, only the main components necessary for explaining the embodiments are shown in a simplified manner. Therefore, the coated cutting tool 1 may include any structural components not shown in the respective drawings referred to. In addition, the dimensions of the components in each drawing do not faithfully represent the dimensions of the actual structural components and the dimensional ratios of the respective components.

[0012] Coated tool 1, such as Figure 1 and Figure 2 The non-limiting example shown may include a substrate 3 and a coating 7 located on a surface 5 of the substrate 3 .

[0013] The coating layer 7 may include a Ti-based film layer 9 (titanium-based film layer). The Ti-based film layer 9 may be in contact with the substrate 3. In other words, the Ti-based film layer 9 may be in contact with and cover the substrate 3. The Ti-based film layer 9 may also be referred to as a base layer.

[0014] Base 3 as Figure 3 In the non-limiting example shown, there may be a crack 11. The crack 11 may extend from the surface 5 of the substrate 3 toward the inside of the substrate 3. In addition, a portion of the Ti-based coating layer 9 may exist in the crack 11. In this case, the bonding strength between the substrate 3 and the coating 7 is easily improved, and the fracture resistance and wear resistance are easily improved. Therefore, the wear resistance and fracture resistance of the coated tool 1 are high.

[0015] The presence of a portion of the Ti-based film layer 9 in the crack 11 may mean that a portion that is continuous with the Ti-based film layer 9 and has the same composition as the Ti-based film layer 9 is located inside the crack 11. The composition is homogeneous, which means that the difference between the constituent components is 5% or less. The difference between the constituent components may be 3% or less, or 1% or less.

[0016] For example, if the gas forming the Ti-based film layer 9 is allowed to intrude into the crack 11 during the formation of the Ti-based film layer 9, a portion of the Ti-based film layer 9 is likely to exist in the crack 11. Therefore, the structure in which a portion of the Ti-based film layer 9 exists in the crack 11 can also be said to be a structure in which a portion of the Ti-based film layer 9 intrudes and exists in the crack 11. In addition, the crack 11 can also be called a fissure. The crack 11 can be open at the surface 5 of the substrate 3.

[0017] Confirmation that a portion of the Ti-based coating layer 9 is present in the crack 11 can be performed, for example, by Auger Electron Spectroscopy (AES). Specifically, it can be performed by cross-sectional observation using EDS (Energy Dispersive X-ray Spectroscopy) attached to an electron microscope. Examples of electron microscopes include scanning electron microscopes (SEM) and transmission electron microscopes (TEM).

[0018] In cross-sectional observation, when a recess is formed from the surface 5 of the substrate 3 toward the inside of the substrate 3, with a width of 0.05 to 3 μm and a depth more than twice the width, it can be said that the recess is a crack.

[0019] The cross-section in cross-sectional observation can be a cross-section of the substrate 3 orthogonal to the surface 5. In the cross-section of the substrate 3 orthogonal to the surface 5, the area ratio occupied by the Ti-based film layer 9 in the interior of the crack 11 can be evaluated. When this area ratio is 100%, it means that the Ti-based film layer 9 exists throughout the interior of the crack 11. For example, when the above area ratio is 30% or more, it can be regarded that a part of the Ti-based film layer 9 exists in the crack 11. Also, the upper limit value of the above area ratio is not particularly limited. For example, there is no problem even if the above area ratio is 100%.

[0020] The substrate 3 can have a first region 13 existing from the surface 5 toward the inside. The thickness of the first region 13 can be 0.5 to 30 μm. The crack 11 can be located in the first region 13.

[0021] The substrate 3 can have a plurality of cracks 11. A part of the Ti-based film layer 9 can exist in each of the plurality of cracks 11. In this case, the bonding strength between the substrate 3 and the coating 7 is likely to be improved.

[0022] The number of cracks 11 can be measured by cross-sectional observation using an electron microscope. For example, an electron microscope can be used to photograph the cross-section of the substrate 3 orthogonal to the surface 5 at a magnification of 10,000 times, and the number of cracks 11 existing within a range of 8.9 μm × 11.8 μm in the obtained electron microscope photograph can be measured. The photographing positions can be multiple. For example, the photographing positions can be 5. The number of cracks 11 per field of view of the electron microscope photograph can be 1 to 3.

[0023] In the cross-section of the substrate 3 orthogonal to the surface 5, the crack 11 can have a bent part such as Figure 3 shown in a non-limiting example. At this time, the bonding strength between the substrate 3 and the coating 7 is likely to be improved. In particular, when bent in a manner approaching parallel to the surface 5 of the substrate 3, the bonding strength between the substrate 3 and the coating 7 is more likely to be improved.

[0024] The length of the crack 11 can be the size of the crack 11 in the extending direction (longitudinal direction) of the crack 11. In addition, the width of the crack 11 can be the size of the crack 11 in the direction orthogonal to the extending direction of the crack 11 (transverse width direction). The length of the crack 11 can be, for example, 0.5 to 15 μm. The width of the crack 11 can be, for example, 0.05 to 3 μm as described above. Also, when the substrate 3 has a plurality of cracks 11, the length and width of the crack 11 can be an average value. The average value can be the average value of 2 cracks 11.

[0025] The substrate 3 may be a sintered alloy. The sintered alloy may be formed of a cemented carbide. In other words, the substrate 3 may be formed 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). The hard phase may contain WC as a main component. That is, the cemented carbide may be a WC-based cemented carbide. The so-called "main component" may mean the component having the largest mass% value compared with other components.

[0026] The binder phase in the cemented carbide may contain a ferrous metal. As the ferrous metal, for example, cobalt (Co) and nickel (Ni) etc. may be cited. 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 a ferrous metal as a main component. Further, the binder phase may function as a phase that binds adjacent hard phases.

[0027] The substrate 3 may be formed of a cemented carbide. In this case, the hard phase may be formed of WC, or may be formed of at least one cubic crystal structure compound selected from carbides, nitrides, carbon oxides, nitrogen oxides and solid solutions thereof of elements in Groups 4, 5 and 6 of the periodic table and WC. In addition, the binder phase may have Co and / or Ni as a main component.

[0028] The substrate 3 may be formed of a cemented carbide. In this case, the amount of nitrogen (N) contained in the crack 11 may be 2 mass% or more. In other words, the nitrogen content ratio in the part of the Ti-based film layer 9 located in the crack 11 may be 2 mass% or more. In this case, the wear resistance and chipping resistance are liable to be improved. The amount of nitrogen contained in the crack 11 may also be 2 to 30 mass%.

[0029] The amount of carbon (C) contained in the crack 11 may be 2 to 30 mass%. In other words, the carbon content ratio in the part of the Ti-based film layer 9 located in the crack 11 may be 2 to 30 mass%.

[0030] When performing the composition analysis of the crack 11, EDS may be used. In EDS, the acceleration voltage may be set to 20 kV, and the elements Ti, C, N, W, and Co may be selected for the composition analysis. In addition, the composition analysis of the crack 11 may also be performed by cross-sectional observation. Five arbitrary positions may be measured and their average value may be calculated. When the substrate 3 is formed of a cemented carbide, the crack 11 to be measured may be selected as a crack located at the boundary between adjacent WC particles. This is the same in the case of measuring the number of cracks 11.

[0031] When the substrate 3 is a sintered alloy, the sintered alloy can be formed of cermet. In other words, the substrate 3 can be formed of cermet. Cermet can contain a hard phase and a binder phase. The hard phase in cermet, for example, can contain titanium (Ti) compounds. As Ti compounds, for example, titanium carbonitride (TiCN), titanium carbide (TiC), titanium nitride (TiN), etc. can be cited. In addition, the hard phase in cermet can contain Ti compounds as a main component. That is, cermet can be Ti-based cermet.

[0032] The binder phase in cermet can contain iron group metals. The binder phase in cermet can contain at least one of Co and Ni. The binder phase of cermet can contain iron group metals as a main component.

[0033] The composition of the substrate 3, for example, can be measured by EDS. The measurement can be carried out using EDS attached to an electron microscope.

[0034] The Ti-based coating layer 9 can be a single layer, and can also be a laminated structure formed by laminating multiple layers. As the composition of the Ti-based coating layer 9, for example, TiN and TiC, etc. can be cited. For example, when the Ti-based coating layer 9 is a single layer, the Ti-based coating layer 9 can be a TiN layer.

[0035] When the Ti-based coating layer 9 is a laminated structure, the Ti-based coating layer 9 can be a structure formed by alternately laminating a TiN layer and a TiC layer three or more layers. In addition, the layer closest to the substrate 3 can be a TiN layer. That is, the Ti-based coating layer 9 can have a laminated structure formed by alternately laminating a TiN layer and a TiC layer at least three layers, and the layer closest to the substrate 3 in the laminated structure can be a TiN layer. In this case, the wear resistance and chipping resistance are likely to be improved. Also, the number of laminated layers can be set to 3 to 8.

[0036] The coating 7 is not limited to a specific thickness. For example, the average thickness of the Ti-based coating layer 9 can be set to 0.1 to 1 μm. Also, the thickness of the Ti-based coating layer 9 is a value excluding the part present in the crack 11. In addition, when the Ti-based coating layer 9 is a laminated structure, the thickness of the exemplified Ti-based coating layer 9 is the overall thickness. When the Ti-based coating layer 9 is a laminated structure, the thickness of each layer can be the same or different.

[0037] The measurement of the thickness of the coating 7 can be carried out by cross-sectional observation using an electron microscope. For example, the thickness can be measured at 10 or more measurement points at an arbitrary position of the Ti-based coating layer 9, and the average value can be calculated. This is the same for other layers described below.

[0038] The coating 7 is as Figure 2In an exemplary and non-limiting case shown, a Ti-based coating layer 9, a first TiCN layer 15, a second TiCN layer 17, a TiCNO layer 19 (titanium carbonitride oxide layer), and an Al2O3 layer 21 (aluminum oxide layer) are successively provided starting from the substrate 3. In this case, the lifespan of the coated cutting tool 1 is easily extended.

[0039] The first TiCN layer 15 can be a so-called MT (moderate temperature) - TiCN layer. Additionally, the average thickness of the first TiCN layer 15 can be set to 2 to 15 μm. In this case, the first TiCN layer 15 has high abrasion resistance and chipping resistance. Also, the titanium carbonitride crystals contained in the first TiCN layer 15 can be columnar crystals elongated along the thickness direction of the coating 7. The first TiCN layer 15 can be in contact with the Ti-based coating layer 9.

[0040] The second TiCN layer 17 can be a so-called HT (high temperature) - TiCN layer. Additionally, the average thickness of the second TiCN layer 17 can be set to 10 to 900 nm. The second TiCN layer 17 can be in contact with the first TiCN layer 15.

[0041] The average thickness of the TiCNO layer 19 can be set to 200 to 2000 nm. In this case, the hardness of the TiCNO layer 19 is difficult to reduce. Additionally, the Al2O3 layer 21 easily forms an α-type crystal structure. Also, the TiCNO layer 19 can be in contact with the second TiCN layer 17.

[0042] The average thickness of the Al2O3 layer 21 can be set to 1 to 15 μm. The average thickness of the Al2O3 layer 21 can be greater than the average thickness of the TiCNO layer 19. The Al2O3 layer 21 can be in contact with the TiCNO layer 19.

[0043] The coating 7 can be located on the entire surface 5 of the substrate 3, or alternatively, it can be located only on a part. That is, the coating 7 can be located on at least a part of the surface 5 of the substrate 3.

[0044] The coating 7 can be formed by Chemical Vapor Deposition (CVD) method. In other words, the coating 7 can be a CVD film. Also, the coating 7 can be a PVD film formed by Physical Vapor Deposition (PVD) method.

[0045] In Figure 1 an example of a cutting insert as the coated cutting tool 1 is shown. Also, the form of the coated cutting tool 1 is not limited to the cutting insert.

[0046] The coated cutting tool 1 may have the following: a first face 23 (upper face); a second face 25 (side face) adjacent to the first face 23; and a cutting edge 27 located at the intersection of the first face 23 and the second face 25.

[0047] The first face 23 may be a rake face. The entire first face 23 may be a rake face, or alternatively, only a part thereof may be a rake face. For example, the region along the cutting edge 27 in the first face 23 may be a rake face.

[0048] The second face 25 may be a flank face. The entire second face 25 may be a flank face, or alternatively, only a part thereof may be a flank face. For example, the region along the cutting edge 27 in the second face 25 may be a flank face.

[0049] The cutting edge 27 may be located at the entire intersection of the first face 23 and the second face 25, or alternatively, may be located only at a part of the intersection. The cutting edge 27 can be used for cutting a workpiece when the coated cutting tool 1 is used to produce a machined product.

[0050] The coated cutting tool 1 may have a through-hole 29. When the coated cutting tool 1 is fixed to a tool holder, the through-hole 29 can be used for mounting a bolt or a clamping member or the like. The through-hole 29 may be formed from the first face 23 to the face (lower face) on the opposite side of the first face 23, and may be open on these faces. Also, there is no problem with a structure in which the through-hole 29 opens in a region opposite to each other in the second face 25.

[0051] The coated cutting tool 1 may be in the shape of a quadrilateral plate. Also, the shape of the coated cutting tool 1 is not limited to a quadrilateral plate. For example, the first face 23 may also be triangular, pentagonal, hexagonal, or circular.

[0052] The coated cutting tool 1 is not limited to a specific size. For example, the length of one side of the first face 23 can be set to about 3 to 20 mm. Also, the height from the first face 23 to the face (lower face) on the opposite side of the first face 23 can be set to about 5 to 20 mm.

[0053] <Manufacturing method of coated cutting tool>

[0054] Next, a manufacturing method of a non-limiting coated cutting tool of the present invention will be described.

[0055] When manufacturing a coated cutting tool, a substrate can be fabricated first. As an example of the substrate, the case of fabricating a substrate formed of a sintered alloy will be described. First, inorganic powders such as carbides, nitrides, carbonitrides, and oxides that can form a substrate by sintering can be appropriately mixed with metal powders, carbon powders, etc. to obtain a mixed powder. Second, using this mixed powder, it can be formed into a prescribed cutting tool shape by known forming methods such as stamping, casting, extrusion, and cold isostatic pressing. Then, the obtained formed body can be sintered in a vacuum or a non-oxidizing atmosphere to obtain a substrate formed of a sintered alloy.

[0056] Honing (lapping) can be performed on the surface of the obtained substrate. In honing, shot peening can be performed with an air pressure of 0.1 to 0.3 MPa and a slurry concentration of 5 to 15 mass%. In this case, cracks extending from the surface of the substrate toward the inside of the substrate are likely to be formed.

[0057] Next, a coating can be formed on the surface of the obtained substrate by CVD method to obtain a coated cutting tool. Taking the case where the coating sequentially has a Ti-based film layer, a first TiCN layer (MT-TiCN layer), a second TiCN layer (HT-TiCN layer), a TiCNO layer, and an Al2O3 layer from the substrate as an example, the film formation conditions for each layer will be described in sequence.

[0058] When forming a TiN layer as the Ti-based film layer, first, as the reaction gas composition, a mixed gas containing titanium tetrachloride (TiCl4) gas at 0.5 to 10 vol%, nitrogen (N2) gas at 10 to 60 vol%, and the balance hydrogen (H2) gas can be adjusted. Then, this mixed gas can be introduced into the furnace chamber, and the film formation temperature can be set to 790 to 940 °C and the pressure can be set to 8 to 50 kPa to form the TiN layer.

[0059] When forming a TiC layer as the Ti-based film layer, first, as the reaction gas composition, a mixed gas containing titanium tetrachloride (TiCl4) gas at 0.5 to 10 vol%, methane (CH4) gas at 5 to 30 vol%, and the balance hydrogen (H2) gas can be adjusted. Then, this mixed gas can be introduced into the furnace chamber, and the film formation temperature can be set to 790 to 940 °C and the pressure can be set to 8 to 50 kPa to form the TiC layer.

[0060] When alternately laminating at least 3 layers of TiN layers and TiC layers, the film formation of the TiN layer and the film formation of the TiC layer can be alternately repeated.

[0061] Here, the film-forming gas of the Ti-based film layer can be intentionally made to penetrate into the interior of the crack, and a part of the Ti-based film layer can exist in the crack. For example, when the Ti-based film layer is a single layer such as a TiN layer, if the film-forming temperature is set to a low temperature of 790 to 820 °C, the Ti-based film particles are atomized and easily penetrate into the interior of the crack. In addition, when the Ti-based film layer is a laminated structure formed by alternately laminating at least three layers of a TiN layer and a TiC layer, the Ti-based film particles are also atomized and easily penetrate into the interior of the crack. Moreover, when simply forming the Ti-based film layer, it is difficult for the gas to penetrate into the interior of the crack.

[0062] The first TiCN layer (MT-TiCN layer) can be formed as follows. First, as the reaction gas composition, a mixed gas can be adjusted to contain titanium tetrachloride (TiCl4) gas at 0.5 to 10% by volume, nitrogen (N2) gas at 5 to 60% by volume, acetonitrile (CH3CN) gas at 0.1 to 3% by volume, and the balance being hydrogen (H2) gas. Then, this mixed gas can be introduced into the furnace chamber, and the film-forming temperature can be set to a relatively low temperature of 780 to 880 °C, and the pressure can be set to 5 to 25 kPa to form the first TiCN layer. If the content ratio of acetonitrile (CH3CN) gas is more in the later stage of film formation than in the initial stage of film formation, the average crystal width of the titanium carbonitride columnar crystals constituting the first TiCN layer is likely to be larger on the surface side than on the substrate side.

[0063] The second TiCN layer (HT-TiCN layer) can be formed as follows. First, as the reaction gas composition, a mixed gas can be adjusted to contain titanium tetrachloride (TiCl4) gas at 1 to 4% by volume, nitrogen (N2) gas at 5 to 20% by volume, methane (CH4) gas at 0.1 to 10% by volume, and the balance being hydrogen (H2) gas. Then, this mixed gas can be introduced into the furnace chamber, the film-forming temperature can be set to 900 to 990 °C, and the pressure can be set to 5 to 40 kPa to form the second TiCN layer. The second TiCN layer is formed at a higher temperature than the first TiCN layer.

[0064] The TiCNO layer can be formed as follows. First, as the reaction gas composition, a mixed gas can be adjusted to contain titanium tetrachloride (TiCl4) gas at 3 to 15% by volume, nitrogen (N2) gas at 3 to 50% by volume, methane (CH4) gas at 0.5 to 15% by volume, carbon monoxide (CO) gas at 0.5 to 10% by volume, and the balance being hydrogen (H2) gas. Then, this mixed gas can be introduced into the furnace chamber, the film-forming temperature can be set to 900 to 1010 °C, and the pressure can be set to 5 to 40 kPa to form the TiCNO layer.

[0065] The Al2O3 layer can be formed by the following method. First, as the reaction gas composition, a mixed gas can be adjusted to contain 3.5 to 15% by volume of aluminum trichloride (AlCl3) gas, 0.5 to 2.5% by volume of hydrogen chloride (HCl) gas, 0.5 to 5% by volume of carbon dioxide (CO2) gas, 0 to 1% by volume of hydrogen sulfide (H2S) gas, and the balance being hydrogen (H2) gas. Then, this mixed gas can be introduced into the furnace chamber, and the film-forming temperature can be set to 900 to 1010 °C, and the pressure can be set to 5 to 20 kPa to form the Al2O3 layer.

[0066] Furthermore, the above manufacturing method is an example of a coated cutting tool manufacturing method. Therefore, the coated cutting tool is of course not limited to being manufactured by the above manufacturing method.

[0067] <Cutting Tool>

[0068] Next, for a non-limiting cutting tool 101 of the present invention, an example of having the above coated cutting tool 1 is cited and illustrated with the accompanying drawings.

[0069] The cutting tool 101, as Figure 4 a non-limiting example shown, can have a tool shank 103 and a coated cutting tool 1. The tool shank 103 can extend from the first end 103a toward the second end 103b. Additionally, a clamping groove 105 can be provided on the side of the first end 103a. The coated cutting tool 1 can be located in the clamping groove 105. When the cutting tool 101 has the coated cutting tool 1, stable cutting can be performed because the coated cutting tool 1 has high wear resistance and chipping resistance.

[0070] The clamping groove 105 can be the part for mounting the coated cutting tool 1. The clamping groove 105 can open on the outer peripheral surface of the tool shank 103 and the end surface on the side of the first end 103a.

[0071] The coated cutting tool 1 can be mounted in the clamping groove 105 by a method in which at least a part of the cutting edge 27 protrudes from the tool shank 103. Additionally, the coated cutting tool 1 can be mounted in the clamping groove 105 by bolts 107. That is, the bolts 107 are inserted into the through holes 29 of the coated cutting tool 1, the front ends of these bolts 107 are inserted into the threaded holes formed in the clamping groove 105, and the bolts 107 are fixed in the threaded holes, whereby the coated cutting tool 1 can be mounted into the clamping groove 105. At this time, the lower surface of the coated cutting tool 1 can be in direct contact with the clamping groove 105, or a spacer can also be interposed between the coated cutting tool 1 and the clamping groove 105.

[0072] As the material of the tool shank 103, for example, steel and cast iron can be cited. When the material of the tool shank 103 is steel, the tool shank 103 has high toughness.

[0073] In Figure 4In one example shown, a cutting tool 101 for so-called turning is illustrated. As turning, for example, internal diameter machining, external diameter machining, grooving machining, etc. can be cited. Also, the cutting tool 101 (coated tool 1) is not limited to the use for turning. For example, there is no problem in using the coated tool 1 as a cutting tool 101 for milling.

[0074] As described above, a non-limiting coated tool 1 and cutting tool 101 of the present invention have been illustrated, but the present invention is not limited to the above-described embodiments, and of course, any embodiment can be adopted as long as the gist of the present invention is not deviated from.

[0075] For example, in the above non-limiting embodiment, the case where the cutting tool 101 uses the coated tool 1 has been described as an example, but the coated tool 1 can also be applied to other uses. As other uses, for example, wear-resistant parts such as sliding parts or dies, tools such as excavation tools and cutters, and impact-resistant parts, etc. can be cited.

[0076] In addition, the coated tool 1 and the cutting tool 101 can have the following configurations.

[0077] (1) A coated tool which is a coated tool having a substrate and a coating on the surface of the substrate, wherein the coating has a Ti-based film layer, the Ti-based film layer is in contact with the substrate, the substrate has a crack extending from the surface toward the inside of the substrate, and a part of the Ti-based film layer exists in the crack.

[0078] (2) The coated tool according to (1) above, wherein the substrate can be a sintered alloy formed of cemented carbide or cermet containing a hard phase and a binder phase.

[0079] (3) The coated tool according to (1) above, wherein the substrate is formed of cemented carbide containing a hard phase and a binder phase, the hard phase is formed of tungsten carbide, or is formed of at least one cubic crystal structure compound selected from carbides, nitrides, carbon oxides, nitrogen oxides and solid solutions thereof of elements in Groups 4, 5, and 6 of the periodic table and tungsten carbide, and the main component of the binder phase can be cobalt and / or nickel.

[0080] (4) The coated tool according to (1) above, wherein the substrate is formed of cemented carbide containing a hard phase and a binder phase, and the amount of nitrogen contained in the crack can be 2% by mass or more.

[0081] (5) The coated tool according to (4) above, wherein the amount of carbon contained in the crack can be 2 to 30% by mass.

[0082] (6) The coated cutting tool according to any one of (1) to (5) above, wherein the Ti-based film layer has a laminated structure formed by laminating at least three layers of TiN layers and TiC layers alternately, and the layer closest to the substrate in the laminated structure may be the TiN layer.

[0083] (7) The coated cutting tool according to any one of (1) to (6) above, wherein the coating may sequentially have the Ti-based film layer, the first TiCN layer, the second TiCN layer, the TiCNO layer, and the Al2O3 layer starting from the substrate.

[0084] (8) A cutting tool, which may include: a tool shank extending from a first end toward a second end and having a clamping groove on the first end side; and any one of the coated cutting tools according to (1) to (7) above located in the clamping groove.

[0085] Hereinafter, examples will be listed to illustrate the present invention in detail, but the present invention is not limited by the following examples.

[0086] Examples

[0087] [Sample Nos. 1 to 5]

[0088] <Fabrication of Coated Cutting Tool>

[0089] First, a substrate was fabricated. Specifically, a mixed powder was obtained by mixing 7% by mass of cobalt metal powder with an average particle size of 1.2 μm, 2% by mass of titanium carbide powder with an average particle size of 2 μm, 1% by mass of niobium carbide powder with an average particle size of 2 μm, 3% by mass of tantalum carbide with an average particle size of 1.2 μm, 1% by mass of zirconium carbide with an average particle size of 1.2 μm, and the balance being tungsten carbide powder with an average particle size of 1.5 μm. Also, the average particle size of each powder was the value measured by the Microtrac method.

[0090] Next, the obtained mixed powder was stamped into a tool shape (CNMG120408) to obtain a formed body. Then, after dewaxing treatment was performed on the obtained formed body, it was fired in a non-oxidizing atmosphere to obtain a substrate formed of cemented carbide. Also, the firing temperature was set at 1450 °C and the firing time was set at 1 hour, and an argon atmosphere was used as the non-oxidizing atmosphere.

[0091] The composition of the obtained cemented carbide was measured by EDS. Specifically, cross-sectional observation was performed using EDS attached to SEM, and measurement was performed under the conditions of an average value measured at 5 locations at a magnification of 5000 to 20000 times. Five elements, tungsten carbide, cobalt, titanium, carbon, and nitrogen, were selected as the measurement elements for EDS.

[0092] The results of the EDS measurement show that the obtained cemented carbide contains a hard phase and a binder phase. More specifically, the obtained cemented carbide contains a hard phase formed from WC and a binder phase mainly composed of Co.

[0093] Honing (lapping) was performed on the surface of the obtained substrate. During honing, shot peening was carried out with the air pressure being 0.1 - 0.3 MPa and the slurry concentration being 5 - 15 mass%.

[0094] The cross-section of the substrate after honing was observed by SEM. As a result, the substrate has multiple cracks.

[0095] Next, a coating film was formed on the surface of the obtained substrate by CVD method to obtain the coated cutting tool of the sample shown in Table 1. Also, for the sample shown in Table 1, first, a Ti-based film layer was formed on the surface of the substrate, and on this Ti-based film layer, a first TiCN layer (MT - TiCN layer), a second TiCN layer (HT - TiCN layer), a TiCNO layer, and an Al2O3 layer were sequentially formed. The film formation conditions for each are as follows.

[0096] (Film formation conditions for the Ti-based film layer)

[0097] When forming a single layer of TiN layer, first, as the reaction gas composition, a mixed gas containing 1 volume% of titanium tetrachloride (TiCl4) gas, 38 volume% of nitrogen (N2) gas, and the balance being hydrogen (H2) gas was adjusted. Then, this mixed gas was introduced into the furnace chamber, and the film formation temperature, pressure, and film formation time were set to the conditions shown in Table 1.

[0098] When alternately laminating at least 3 layers of TiN layer and TiC layer, first, the mixed gas for the TiC layer was adjusted. Specifically, as the reaction gas composition for the TiC layer, a mixed gas containing 2 volume% of titanium tetrachloride (TiCl4) gas, 10 volume% of methane (CH4) gas, and the balance being hydrogen (H2) gas was adjusted. In addition, the same mixed gas as that for forming a single layer of TiN layer was used as the mixed gas for the TiN layer. Then, these mixed gases were alternately introduced into the furnace chamber according to the composition in Table 1, and the film formation temperature, pressure, and film formation time were set to the conditions shown in Table 1.

[0099] Also, in the composition shown in Table 1, for example, "TiN - TiC - TiN" means that a TiN layer, a TiC layer, and a TiN layer are laminated in sequence from the substrate. In addition, the film formation temperature and pressure are the same for the TiN layer and the TiC layer. The film formation time shown in Table 1 is the total of the film formation times of each layer. The film formation time for each layer is calculated according to the formula: (film formation time) / (number of layers).

[0100] (Film formation conditions of the first TiCN layer (MT-TiCN layer))

[0101] First, as the reaction gas composition, a mixed gas was adjusted to contain 4 vol% of titanium tetrachloride (TiCl4) gas, 23 vol% of nitrogen (N2) gas, 0.4 vol% of acetonitrile (CH3CN) gas, and the balance being hydrogen (H2) gas. Then, this mixed gas was introduced into the furnace chamber, and the film formation temperature was set at 850 °C, and the pressure was set at 9 kPa. Also, the film formation time was set at 400 minutes.

[0102] (Film formation conditions of the second TiCN layer (HT-TiCN layer))

[0103] First, as the reaction gas composition, a mixed gas was adjusted to contain 4 vol% of titanium tetrachloride (TiCl4) gas, 20 vol% of nitrogen (N2) gas, 8 vol% of methane (CH4) gas, and the balance being hydrogen (H2) gas. Then, this mixed gas was introduced into the furnace chamber, and the film formation temperature was set at 950 °C, and the pressure was set at 13 kPa. Also, the film formation time was set at 80 minutes.

[0104] (Film formation conditions of the TiCNO layer)

[0105] First, as the reaction gas composition, a mixed gas was adjusted to contain 4 vol% of titanium tetrachloride (TiCl4) gas, 20 vol% of nitrogen (N2) gas, 8 vol% of methane (CH4) gas, 2 vol% of carbon monoxide (CO) gas, and the balance being hydrogen (H2) gas. Then, this mixed gas was introduced into the furnace chamber, and the film formation temperature was set at 950 °C, and the pressure was set at 10 kPa. Also, the film formation time was set at 30 minutes.

[0106] (Film formation conditions of the Al2O3 layer)

[0107] First, as the reaction gas composition, a mixed gas was adjusted to contain 3.7 vol% of aluminum trichloride (AlCl3) gas, 0.7 vol% of hydrogen chloride (HCl) gas, 4.3 vol% of carbon dioxide (CO2) gas, 0.3 vol% of hydrogen sulfide (H2S) gas, and the balance being hydrogen (H2) gas. Then, this mixed gas was introduced into the furnace chamber, and the film formation temperature was set at 950 °C, and the pressure was set at 7.5 kPa. Also, the film formation time was set at 380 minutes.

[0108] Regarding the obtained coated cutting tool, in accordance with the method exemplified above, it was confirmed that a part of the Ti-based coating layer was present in the crack. Specifically, it was carried out by cross-sectional observation using EDS attached to the SEM. The measurement results are shown in the column of "Ti-based coating layer present in the crack" in Table 1. In this column, "Yes" indicates that a part of the Ti-based coating layer is present in the crack, and "No" indicates that no part of the Ti-based coating layer is present in the crack. In addition, the composition analysis of the crack was carried out in accordance with the method exemplified above. The measurement results are shown in the column of "Composition of the crack" in Table 1.

[0109] <Evaluation>

[0110] Regarding the obtained coated cutting tool, a cutting test was carried out under the following conditions.

[0111] Machining method: Turning

[0112] Cutting speed: 300 m / min

[0113] Feed rate: 0.3 mm / rev

[0114] Cutting depth: 2 mm

[0115] Workpiece material: SCM435 φ200 round bar

[0116] Machining state: WET

[0117] The test results are shown in Table 1. Also, the so-called "cutting time (minutes) until chipping occurs" in Table 1 indicates the time until chipping occurs at the cutting edge tip. In addition, the so-called "cutting time (minutes) until the wear amount reaches 0.2 mm" indicates the time until the wear amount reaches 0.2 mm on the flank face of the cutting edge.

[0118]

Table 1

[0119]

[0120] Comparing Specimen Nos. 1 to 3 with Specimen Nos. 4 to 5, it showed results of high wear resistance and chipping resistance.

[0121] Explanation of reference numerals

[0122] 1... Coated cutting tool

[0123] 3... Substrate

[0124] 5... Surface

[0125] 7... Coating

[0126] 9... Ti-based coating layer

[0127] 11... Crack

[0128] 13… First region

[0129] 15… First TiCN layer

[0130] 17… Second TiCN layer

[0131] 19… TiCNO layer

[0132] 21… Al2O3 layer

[0133] 23… First face (upper surface)

[0134] 25… Second face (side face)

[0135] 27… Cutting edge

[0136] 29… Through hole

[0137] 101… Cutting tool

[0138] 103… Tool shank

[0139] 103a… First end

[0140] 103b… Second end

[0141] 105… Groove

[0142] 107… Bolt

Claims

1. A coated cutting tool, comprising a substrate and a coating on the surface of the substrate, wherein, the coating has a Ti-based film layer, the Ti-based film layer is in contact with the substrate, the substrate has cracks extending from the surface toward the interior of the substrate, a part of the Ti-based film layer is present in the cracks.

2. The coated cutting tool according to claim 1, wherein, The substrate is a sintered alloy formed of cemented carbide containing a hard phase and a binder phase, or a sintered alloy formed of cermet.

3. The coated cutting tool according to claim 1, wherein, the substrate is formed of cemented carbide containing a hard phase and a binder phase, the hard phase is formed of tungsten carbide, or is formed of tungsten carbide and at least one cubic crystal structure compound selected from carbides, nitrides, carbon oxides, nitrogen oxides and solid solutions thereof of elements in Groups 4, 5, and 6 of the periodic table, the binder phase has cobalt and / or nickel as a main component.

4. The coated cutting tool according to claim 1, wherein, the substrate is formed of cemented carbide containing a hard phase and a binder phase, the amount of nitrogen contained in the cracks is 2% by mass or more.

5. The coated cutting tool according to claim 4, wherein, the amount of carbon contained in the cracks is 2 to 30% by mass.

6. The coated cutting tool according to any one of claims 1 to 5, wherein, the Ti-based film layer has a laminated structure formed by laminating at least three layers of TiN layers and TiC layers alternately, the layer closest to the substrate in the laminated structure is the TiN layer.

7. The coated cutting tool according to any one of claims 1 to 6, wherein, the coating sequentially has the Ti-based film layer, a first TiCN layer, a second TiCN layer, a TiCNO layer, and an Al2O3 layer from the substrate.

8. A cutting tool, comprising: a tool shank extending from a first end toward a second end and having a card slot on the first end side; the coated cutting tool according to any one of claims 1 to 7 located in the card slot.

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