Coated tools and cutting tools

Abstract

A cemented carbide according to a non-limiting aspect of the present disclosure has a hard phase containing W and C, a solid solution phase containing W, C and Ti, and a binding phase containing an iron group metal. A β-free layer composed only of WC and an iron group metal is provided on the surface of an intersecting region of the cemented carbide where a rake face and a flank face intersect with each other. The average thickness of the β-free layer of the rake face in the intersecting region is a, and the average thickness of the β-free layer of the flank face in the intersecting region is b. The relationship between a and b satisfies b<a. A coated tool according to a non-limiting aspect of the present disclosure comprises the above-described cemented carbide and a coating layer that is arranged on the surface of the cemented carbide. A cutting tool according to a non-limiting example of the present disclosure is provided with: a holder which extends from a first end to a second end, while having a pocket on the first end side; and the above-described coated tool that is arranged in the pocket.

Description

Cross-reference to related applications

[0001] This application claims the priority of Japanese Patent Application No. 2022-051034 filed on March 28, 2022, and incorporates the entire disclosure of the prior application herein by reference.

Technical Field

[0002] The present disclosure relates to cemented carbide, a coated tool using the same, and a cutting tool.

Background Art

[0003] Cemented carbide containing WC (tungsten carbide) as a hard phase is used for a substrate in a coated tool and the like, and is used for a cutting tool such as an end mill. Such cemented carbide is required to have chipping resistance and the like.

[0004] As cemented carbide excellent in chipping resistance, for example, Patent No. 3235259 (Patent Document 1) describes that there is a decarburized β layer at the cutting edge ridge line portion of the cemented carbide, and the thickness of this decarburized β layer is also described. Further, Patent No. 3656838 (Patent Document 2) does not describe that there is a decarburized β layer at the cutting edge ridge line portion of the cemented carbide, and describes adjusting the thickness of the decarburized β layer on the rake face and the flank face.

Summary of the Invention

[0005] A cemented carbide according to a non-limiting aspect of the present disclosure has a hard phase containing W and C, a solid solution phase containing W, C, and Ti, and a binder phase containing a ferrous metal. On the surface of the intersection region between the rake face and the flank face of the cemented carbide, there is a decarburized β layer consisting only of WC and a ferrous metal. Let the average thickness of the decarburized β layer on the rake face in the intersection region be a, and the average thickness of the decarburized β layer on the flank face in the intersection region be b. The relationship between a and b satisfies b < a.

[0006] A coated tool according to a non-limiting aspect of the present disclosure has the above cemented carbide and a coating layer located on the surface of the cemented carbide.

[0007] A non-limiting aspect of the cutting tool of the present disclosure includes a holder extending from a first end to a second end and having a pocket on the first end side, and the coated tool described above positioned in the pocket. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a non-limiting single-sided cemented carbide of the present disclosure. [Figure 2] 2 is a cross-sectional view of section II of the cemented carbide shown in FIG. 1, and is a cross-sectional view perpendicular to the intersection region when viewed from above (plan view) from the rake face. FIG. [Figure 3] 1 is a cross-sectional view showing the vicinity of a surface of a non-limiting coated tool of the present disclosure. [Figure 4] 1 is a cross-sectional view showing the vicinity of a surface of a non-limiting coated tool of the present disclosure. [Figure 5] FIG. 1 is a perspective view of a non-limiting one-sided cutting tool of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Cemented carbide> Hereinafter, one aspect of the cemented carbide 1 of the present disclosure will be described in detail with reference to the drawings. However, for the sake of convenience, the figures referred to below show only the main components necessary for explaining the embodiment in a simplified form. Therefore, the cemented carbide 1 may include optional components not shown in the figures referred to. Furthermore, the dimensions of the components in the figures do not faithfully represent the actual dimensions of the components or the dimensional ratios of each component. These points also apply to the coated tools and cutting tools described below.

[0010] The cemented carbide 1 may have a hard phase, a solid solution phase and a binder phase.

[0011] The hard phase may contain W (tungsten) and C (carbon). In other words, the hard phase may contain WC. The hard phase may contain WC as the main component. The "main component" may mean the component having the largest mass% value compared to other components. Specifically, the top two mass% values ​​of the components contained in the hard phase may be W and C.

[0012] The solid solution phase may contain W, C, and Ti (titanium). The solid solution phase may contain W, C, and Ti as main components. That is, in the solid solution phase, the total mass% of W, C, and Ti may be the largest. Furthermore, the top three mass% values ​​of the components contained in the solid solution layer may be W, C, and Ti.

[0013] The binder phase may contain an iron group metal. Examples of iron group metals include Co (cobalt) and Ni (nickel). The binder phase may contain at least one of Co and Ni. The binder phase may contain an iron group metal as a main component. The binder phase may function as a phase that bonds adjacent hard phases. Iron group metals, including Co and Ni as examples, may have the largest mass % value among the components contained in the binder phase.

[0014] The compositions of the hard phase, solid solution phase, and binder phase may be measured, for example, by energy dispersive X-ray spectroscopy (EDS). The measurements may be performed using an EDS attached to an electron microscope. Examples of electron microscopes include scanning electron microscopes (SEM) and transmission electron microscopes (TEM).

[0015] As shown in a non-limiting example in FIGS. 1 and 2, the cemented carbide 1 may have a rake face 3 and a flank face 5. That is, the cemented carbide 1 may have a cutting tool shape. The cemented carbide 1 may also have a plate shape. For example, as shown in a non-limiting example in FIG. 1, the cemented carbide 1 may have a square plate shape. In this case, the top surface may be the rake face 3, and the side surface may be the flank face 5. The shape of the cemented carbide 1 is not limited to a square plate shape. For example, the rake face 3 may be triangular, pentagonal, hexagonal, or circular.

[0016] The cemented carbide 1 is not limited to a specific size. For example, the width D1 of the rake face 3 may be set to 3 to 20 mm. The width D2 of the flank 5 may be set to 5 to 20 mm. The widths D1 and D2 may be dimensions in a direction perpendicular to the ridge line between the rake face 3 and the flank 5.

[0017] The cemented carbide 1 may have an intersection region 7 between the rake face 3 and the flank 5. The intersection region 7 is the cutting edge ridgeline, and the cutting edge may be honed as a cutting edge treatment, with the treated portion being the cutting edge ridgeline. Honing may be a processing method in which a grinding stone (hone) is pressed against the cutting edge and rotated back and forth to polish the cutting edge. In other words, the intersection region 7 may be the honed region of the intersection ridgeline between the rake face 3 and the flank 5. Specifically, the intersection region 7 may be a range S1 from a boundary L1 on the rake face 3 side of the cutting edge ridgeline when viewed from above (in a plan view) from the rake face 3 to the flank 5, and a range S2 from a boundary L2 on the flank 5 side of the cutting edge ridgeline when viewed from above (in a plan view) from the flank 5 to the rake face 3 (see FIG. 2 ).

[0018] If it is difficult to identify the boundary L1, the position 80 μm from the flank 5 when viewed from above the rake face 3 may be regarded as the boundary L1. If it is difficult to identify the boundary L2, the position 60 μm from the rake face 3 when viewed from above the flank 5 may be regarded as the boundary L2.

[0019] The intersection region 7 may have a convex curved shape. However, the shape of the intersection region 7 is not limited to a convex curved shape. The intersection region 7 may have, for example, a chamfered planar shape. Note that the planar intersection region 7 is inclined with respect to the rake face 3 and the flank 5, so the end of the intersection region 7 on the rake face 3 side and the end of the intersection region 7 on the flank 5 side can each be easily identified. Furthermore, when the intersection region 7 has a convex curved shape, the end of the intersection region 7 on the rake face 3 side and the end of the intersection region 7 on the flank 5 side can each be easily identified due to the difference between the planar rake face 3 and flank 5 and the convex curved intersection region 7.

[0020] The intersection region 7 may be located on a part of the intersection ridge between the rake face 3 and the flank face 5, or may be located on the entire intersection ridge. The intersection region 7 can be used for cutting the workpiece.

[0021] As a non-limiting example shown in Fig. 2, the cemented carbide 1 may have a β-depleted layer 9 made only of WC and an iron-group metal on the surface of the intersection region 7. The β-depleted layer 9 is rich in iron-group metals such as Co and has excellent toughness, and can function as a layer that absorbs impacts that occur between the cemented carbide 1 and the workpiece during cutting and suppresses chipping. Therefore, when the cemented carbide 1 has the β-depleted layer 9 on the surface of the intersection region 7, the intersection region 7 is less likely to chip.

[0022] The β-depleted layer 9 consisting only of WC and iron-group metals means that almost all of the components constituting the β-depleted layer 9 are WC and iron-group metals. The β-depleted layer 9 may contain impurities at a level unavoidable in the manufacturing process. The total content of impurities should be 3 mass% or less, in other words, the total content of WC and iron-group metals should be 97 mass% or more.

[0023] The cemented carbide 1 may have a β-phase depleted layer 9 on the entire surface of the intersection region 7. In other words, the entire surface of the intersection region 7 of the cemented carbide 1 may be the β-phase depleted layer 9. Further, the cemented carbide 1 may also have a β-phase depleted layer 9 on the surface other than the intersection region 7. The iron-group metal in the β-phase depleted layer 9 may have the same composition as the iron-group metal in the bonding phase. The confirmation of the β-phase depleted layer 9 may be performed, for example, by EDS.

[0024] Here, the average thickness of the β-phase depleted layer 9 on the rake face 3 in the intersection region 7 may be defined as a, and the average thickness of the β-phase depleted layer 9 on the flank face 5 in the intersection region 7 may be defined as b. And the relationship between a and b may satisfy b < a. In this case, cracks, chipping, etc. are less likely to occur in the intersection region 7, and the intersection region 7 is less likely to be damaged. Therefore, the cemented carbide 1 has high damage resistance.

[0025] The relationship between a and b may satisfy 1 < a / b ≤ 2.5. In this case, the damage resistance of the cemented carbide 1 is likely to be improved.

[0026] The relationship between a and b may satisfy 1.5 ≤ a / b ≤ 2.5. In this case, the damage resistance of the cemented carbide 1 is even more likely to be improved.

[0027] The average thickness of the β-phase depleted layer 9 on the rake face 3 in the intersection region 7 may mean the average thickness of the β-phase depleted layer 9 at the end on the rake face 3 side of the intersection region 7 as seen from the rake face 3. Therefore, the average thickness of the β-phase depleted layer 9 on the rake face 3 in the intersection region 7 may also be described as the average thickness of the β-phase depleted layer 9 in the region S1a located at the end on the rake face 3 side of the intersection region 7. The region S1a may be, for example, a region 10 μm from the boundary portion L1.

[0028] Also, the average thickness of the β-phase depleted layer 9 on the flank face 5 in the intersection region 7 may mean the average thickness of the β-phase depleted layer 9 at the end on the flank face 5 side of the intersection region 7 as seen from the flank face 5. Therefore, the average thickness of the β-phase depleted layer 9 on the flank face 5 in the intersection region 7 may also be described as the average thickness of the β-phase depleted layer 9 in the region S2a located at the end on the flank face 5 side of the intersection region 7. The region S2a may be, for example, a region 5 μm from the boundary portion L2.

[0029] The thickness of the β-depleted layer 9 may be measured by cross-sectional observation using an electron microscope. The cross-section to be observed may be, for example, a cross-section as shown in FIG. 2. That is, the cross-section to be observed may be a cross-section perpendicular to the intersection region 7 when viewed from above (in plan view) from the rake face 3. Then, in this cross-section, the thickness of the β-depleted layer 9 may be measured at five or more measurement points at 1 μm intervals over a width of 5 μm or more at any position in region S1a or region S2a, and the average value may be calculated.

[0030] a and b are not limited to a specific thickness. For example, a may be set to 7.3 to 14.3 μm, and b may be set to 2.9 to 13 μm.

[0031] The average thickness of the β-depleted layer 9 in the intersection region 7 may monotonically decrease from the rake face 3 side toward the flank face 5 side. When the average thickness of the β-depleted layer 9 has the above-described configuration, cracks, chipping, etc. are even less likely to occur in the intersection region 7, and the intersection region 7 is even less likely to be damaged.

[0032] Furthermore, the intersection region 7 may further have a region located between the end on the rake face 3 side and the end on the flank face 5 side, where the β-depleted layer 9 has an average thickness of c. In other words, the intersection region 7 may further have another region between region S1a and region S2a, where the average thickness of the β-depleted layer 9 in this region may be c. In this case, c may be smaller than a and b. When the average thickness of the β-depleted layer 9 is as described above, the β-depleted layer 9 at the cutting edge can be made thin, thereby ensuring the sharpness of the cutting edge.

[0033] When the intersection region 7 has a convex curved shape in cross section, as in the non-limiting example shown in Figure 2, the region where the β-depletion layer 9 has an average thickness of c may be located at the smallest radius of curvature in the intersection region 7. Specifically, the radius of curvature of the intersection region 7 in the region where the β-depletion layer 9 has an average thickness of c may be smaller than the radius of curvature of the intersection region 7 in regions S1a and S2a. When the intersection region 7 has the above configuration, the cutting edge can be made sharp, ensuring the sharpness of the cutting edge.

[0034] The region where the β-depleted layer 9 has an average thickness of c may be located closer to the flank 5 than to the rake face 3. In other words, the region where the β-depleted layer 9 has an average thickness of c may be located closer to the flank 5 than to the rake face 3. In this case, the thickness of the β-depleted layer 9 on the rake face 3 increases, which has the advantage of improving chipping resistance.

[0035] The width of the intersection region 7 when viewed from above the rake face 3 may be larger than the width of the intersection region 7 when viewed from above the flank 5. In this case, the advantage of increasing the radius of curvature of the honing of the rake face 3 is that chipping resistance is improved.

[0036] <Method of manufacturing cemented carbide> Next, a non-limiting method for manufacturing one surface of a cemented carbide according to the present disclosure will be described using an example in which cemented carbide 1 is manufactured.

[0037] First, WC powder, Co powder, TiC powder, etc. may be prepared as raw material powders. The proportion of Co powder may be 4 to 12 mass %. The proportion of TiC powder may be 0.5 to 15 mass %. The remainder may be WC powder.

[0038] The average particle size of the raw material powder may be appropriately selected from the range of 0.1 to 10 μm, and may be a value measured by a microtrack method.

[0039] The prepared raw material powders may be mixed and molded to have a rake face 3 and a relief face 5, thereby obtaining a molded body. At this time, the intersection ridge line portion between the rake face 3 and the relief face 5 may be pre-molded into a shape with a chamfer by die pressing. In this case, a β-depleted layer 9 is likely to be formed on the surface of the intersection region 7. The chamfer may include forming the intersection ridge line portion into a convex curved surface shape or a flat surface shape.

[0040] After subjecting the obtained molded body to a debinding treatment, it may be fired to obtain a cemented carbide 1. The firing may be performed in a non-oxidizing atmosphere such as a vacuum, an argon atmosphere, or a nitrogen atmosphere. The firing temperature may be 1450 to 1600 °C. The firing time may be 0.5 to 3 hours. When firing at such a firing temperature and firing time, a β-depleted layer 9 is likely to be formed on the surface of the cemented carbide 1.

[0041] The obtained cemented carbide 1 may be subjected to honing treatment to form an intersection region 7 between the rake face 3 and the relief face 5. Then, polishing may be performed on the intersection region 7 so that the relationship between a and b satisfies b < a, and the thickness of the β-depleted layer 9 may be adjusted. The polishing may be performed, for example, by brush processing, blasting, or barrel processing.

[0042] Note that the above manufacturing method is an example of a method for manufacturing the cemented carbide 1. Therefore, it is needless to say that the cemented carbide 1 is not limited to those produced by the above manufacturing method.

[0043] <Coated tool> Next, a coated tool 101 according to a non-limiting aspect of the present disclosure will be described using FIGS. 3 and 4 by taking the case of having the above cemented carbide 1 as an example.

[0044] As shown in a non-limiting example in Figures 3 and 4, the coated tool 101 may have a cemented carbide 1 and a coating layer 103 located on the surface of the cemented carbide 1. The coated tool 101 may have the cemented carbide 1 as a substrate. When the coated tool 101 has the cemented carbide 1, the cemented carbide 1 has high chipping resistance, which tends to improve cutting performance such as interrupted cutting performance. Therefore, the coated tool 101 has high durability.

[0045] The coating layer 103 may be located on the entire surface of the cemented carbide 1, or may be located on only a portion of the surface. That is, the coating layer 103 may be located on at least a portion of the surface of the cemented carbide 1.

[0046] The coating layer 103 may be formed by a chemical vapor deposition (CVD) method. In other words, the coating layer 103 may be a CVD film. The coating layer 103 may also be a physical vapor deposition (PVD) film formed by a PVD method.

[0047] The coating layer 103 may be a single layer or may be a laminate of multiple layers. Examples of the composition of the coating layer 103 include TiCN (titanium carbonitride), Al2O3 (alumina), and TiN (titanium nitride).

[0048] 3, the coating layer 103 may have, in order from the cemented carbide 1 side, a TiCN layer 105 and an Al2O3 layer 107. The TiCN layer 105 may be in contact with the cemented carbide 1. The Al2O3 layer 107 may be in contact with the TiCN layer 105.

[0049] 4, the coating layer 103 may have, from the cemented carbide 1 side, a TiN layer 109, a TiCN layer 105, and an Al2O3 layer 107. The TiN layer 109 may be in contact with the cemented carbide 1. The TiCN layer 105 may be in contact with the TiN layer 109. The Al2O3 layer 107 may be in contact with the TiCN layer 105.

[0050] The thickness of the coating layer 103 is not limited to a specific value. For example, the thickness of the TiCN layer 105 may be set to approximately 1.0 to 15 μm. The thickness of the Al2O3 layer 107 may be set to approximately 1 to 15 μm. The thickness of the TiN layer 109 may be set to approximately 0.1 to 5 μm. The thickness of the coating layer 103 may be measured by cross-sectional observation using an electron microscope. The thickness of the coating layer 103 may also be an average value. For example, the thickness may be measured at 10 or more measurement points at 1 μm intervals over a width of 10 μm or more at any position on each layer, and the average value may be calculated.

[0051] The coated tool 101 may have a through hole 111. For ease of explanation, the through hole 111 is shown in FIG. 1. The through hole 111 can be used to attach a fixing screw or a clamp member when holding the coated tool 101 in a holder. The through hole 111 may be formed from the top surface (the rake face 3) to the bottom surface located opposite the top surface, or may open in these surfaces. There is no problem with the through hole 111 being configured to open in opposing regions of the side surface (the relief face 5).

[0052] <Method of manufacturing coated tools> Next, a non-limiting method for manufacturing a coated tool on one side according to the present disclosure will be described using the case of manufacturing the coated tool 101 as an example.

[0053] The coated tool 101 may be obtained by forming the coating layer 103 on the surface of the cemented carbide 1 by a CVD method.

[0054] The TiCN layer 105 may be formed as follows. First, a mixed gas containing 0.1 to 10 volume % titanium tetrachloride (TiCl4) gas, 10 to 60 volume % nitrogen (N2) gas, 0.1 to 15 volume % 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 temperature may be set to 800 to 1100°C and the pressure may be set to 5 to 30 kPa, and the TiCN layer 105 may be formed.

[0055] The Al2O3 layer 107 may be formed as follows. First, a mixed gas containing 0.5 to 5 volume percent aluminum trichloride (AlCl3) gas, 0.5 to 3.5 volume percent hydrogen chloride (HCl) gas, 0.5 to 5 volume percent carbon dioxide (CO2) gas, 0.5 volume percent or less 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 temperature may be set to 930 to 1010°C and the pressure may be set to 5 to 10 kPa to form the Al2O3 layer 107.

[0056] The TiN layer 109 may be formed as follows. First, a mixed gas containing 0.1 to 10 volume % titanium tetrachloride (TiCl4) gas, 10 to 60 volume % nitrogen (N2) 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 temperature may be set to 800 to 1010°C and the pressure may be set to 10 to 85 kPa, and the TiN layer 109 may be formed.

[0057] The above-described manufacturing method is one example of a method for manufacturing the coated tool 101. Therefore, it goes without saying that the coated tool 101 is not limited to one manufactured by the above-described manufacturing method.

[0058] <Cutting tools> Next, a non-limiting one-sided cutting tool 201 of the present disclosure will be described with reference to FIG. 5, taking as an example a case where the cutting tool 201 includes the coated tool 101 described above.

[0059] 5, the cutting tool 201 may include a holder 203 extending from a first end 203a to a second end 203b and having a pocket 205 on the side of the first end 203a, and a coated tool 101 positioned in the pocket 205. When the cutting tool 201 includes the coated tool 101, the coated tool 101 has high durability, and therefore the cutting tool 201 has high wear resistance and can perform stable cutting.

[0060] The pocket 205 may be a portion to which the coated tool 101 is attached. The pocket 205 may be open at the outer peripheral surface of the holder 203 and at the end surface on the side of the first end 203a.

[0061] The coated tool 101 may be attached to the pocket 205 so that the intersection region 7 protrudes outward from the holder 203. Alternatively, the coated tool 101 may be attached to the pocket 205 by a fixing screw 207. That is, the coated tool 101 may be attached to the pocket 205 by inserting the fixing screw 207 into the through hole 111 of the coated tool 101 and inserting the tip of the fixing screw 207 into a threaded hole formed in the pocket 205 to screw together the threaded portions. At this time, the lower surface of the coated tool 101 may be in direct contact with the pocket 205, or a sheet may be sandwiched between the coated tool 101 and the pocket 205.

[0062] Examples of materials for the holder 203 include steel and cast iron. When the material for the holder 203 is steel, the holder 203 has high toughness.

[0063] 5 illustrates a cutting tool 201 used for so-called turning. Examples of turning include inner diameter machining, outer diameter machining, and grooving. The application of the cutting tool 201 is not limited to turning. For example, there is no problem in using the cutting tool 201 for milling.

[0064] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to the following examples. [Example]

[0065] [Samples No. 1-6] <Preparation of cemented carbide> First, WC powder with an average particle size of 9 μm, Co powder with an average particle size of 1.5 μm, and TiC powder with an average particle size of 1.5 μm were prepared as raw material powders. The average particle sizes of the raw material powders were measured by the Microtrac method.

[0066] Next, 7% by mass of Co powder, 2% by mass of TiC powder, and the remainder of WC powder were mixed and press-molded into a cutting tool shape (CNMG120408) so as to have a rake face and a flank face, thereby obtaining a green body. At this time, for samples Nos. 1 to 5, the intersection ridge between the rake face and the flank face was formed into a convex curved shape by die pressing, with the corners chamfered.

[0067] The obtained compact was subjected to a binder removal treatment and then sintered at a temperature of 1500°C for 1 hour to obtain a cemented carbide. The obtained cemented carbide was then subjected to a honing treatment to form an intersecting region between the rake face and the flank face.

[0068] The composition of the obtained cemented carbide was measured by EDS. Specifically, cross-section observation was performed using an EDS attached to an SEM at a magnification of 5000 to 20000 times, and the average value of measurements at five locations was measured.

[0069] The EDS measurement results showed that all of the obtained cemented carbides had a hard phase containing W and C as the main components, a solid solution phase containing W, C, and Ti as the main components, and a binder phase containing an iron-group metal (Co) as the main component. Furthermore, the cemented carbide samples Nos. 1 to 5 had a de-β layer consisting only of WC and an iron-group metal (Co) on the entire surface of the intersection region.

[0070] For Samples No. 1 to 5, the intersection region was polished (brushed or blasted) so that a and b had the values ​​shown in Table 1. The values ​​of a and b shown in the column "Average thickness of β-depleted layer in intersection region" in Table 1 were measured according to the method exemplified above.

[0071] <Evaluation> The resulting cemented carbide was evaluated for cutting performance. Specifically, a 1 μm thick TiN layer, a 10 μm thick TiCN layer, and a 6 μm thick Al2O3 layer were formed in this order from the cemented carbide (substrate) by the CVD method to form a coated tool, and then the cutting performance was evaluated under the following conditions. Note that the thickness of each layer is an average value.

[0072] Processing method: Turning Cutting speed: 150m / min Feed: 0.4mm / rev Depth of cut: 0.5mm Work material: SCM440 φ200 round bar Processing condition: WET

[0073] The evaluation results are shown in Table 1. Note that the "number of impacts until chipping of the cutting edge" in the evaluation results in Table 1 indicates the number of impacts until chipping of the cutting edge when cutting, and may also be called an intermittent performance evaluation.

[0074] [Table 1]

[0075] Samples Nos. 1 to 4 clearly had improved stability compared to samples Nos. 5 and 6. In particular, sample No. 6 did not have a de-β layer on the surface of the intersection region, had the fewest number of impacts, had low wear resistance of the cutting edge, and was difficult to use as a cutting tool for stable cutting. [Explanation of symbols]

[0076] 1. Cemented carbide 3. Rake face 5. Flank 7. Intersection area 9...de-β layer 101... Coated tools 103...Covering layer 105...TiCN layer 107...Al2O3 layer 109...TiN layer 111...Through hole 201...cutting tools 203···Holder 203a...1st end 203b...2nd end 205···Pocket 207···Fixing screw

Claims

1. A hard phase containing W and C as main components; a solid solution phase containing W, C, and Ti as main components; a binder phase containing Co as a main component; and a coating layer located on a surface of the cemented carbide, the coating layer has, from the cemented carbide side, a TiN layer, a TiCN layer, and an Al 2 O 3 layer, In a cross section perpendicular to an intersection region between a rake face and a flank face of the cemented carbide, The cemented carbide has a de-β layer consisting only of WC and Co in the intersection region, the average thickness of the deβ layer in the intersection region monotonically decreases from the rake face side toward the flank face side, the average thickness of the deβ layer at the end of the intersection region on the rake face side is a, the average thickness of the β-depleted layer at the end of the intersection region on the flank side is denoted by b, A coated tool, wherein the relationship between a and b satisfies 1.3<a / b≦2.

5.

2. A hard phase containing W and C as main components; a solid solution phase containing W, C, and Ti as main components; a binder phase containing Co as a main component; and a coating layer located on a surface of the cemented carbide, the coating layer has, from the cemented carbide side, a TiN layer, a TiCN layer, and an Al 2 O 3 layer, In a cross section perpendicular to an intersection region between a rake face and a flank face of the cemented carbide, The cemented carbide has a de-β layer consisting only of WC and Co in the intersection region, The intersection region has a convex curved shape, a first region located at an end portion on the rake face side; a second region located at an end portion on the flank side; a third region located between the first region and the second region, The average thickness of the deβ layer in the first region is a, The average thickness of the deβ layer in the second region is b, the average thickness of the deβ layer in the third region is defined as c, the relationship between a and b satisfies 1.3<a / b≦2.5, said c being smaller than said a and said b; The coated tool, wherein the third region is located at the smallest radius of curvature in the intersection region.

3. The coated tool according to claim 2 , wherein a region where the average thickness of the β-depleted layer is c is located closer to the flank face than to the rake face.

4. The coated tool according to claim 1 or 2, wherein a width of the intersection region when viewed from the rake face in a plan view is larger than a width of the intersection region when viewed from the flank face in a plan view.

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

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