Cermet member, cutting insert, and cutting tool

Abstract

A cermet member according to the present disclosure comprises a substrate and a cover layer that covers at least a portion of the surface of the substrate. The substrate comprises: a plurality of hard phases containing TiCN as a main component; a plurality of solid solution phases containing Ti and W; and a plurality of binding phases containing at least one element from among Ni and Co. In a range of an interface length of 10 μm in a cross-section including the interface between the substrate and the cover layer, the maximum value of the length of a first site where the hard phases and the coating layer contact each other is smaller than the average value of the particle diameters of the plurality of solid solution phases.

Description

Cermet components, cutting inserts, and cutting tools

[0001] This disclosure relates to cermet members, cutting inserts, and cutting tools.

[0002] An example of a cutting tool used when machining a workpiece is the cutting tool described in Patent Document 1. The cutting tool described in Patent Document 1 comprises a substrate made of cermet and a coating layer covering the surface of the substrate. The substrate also has a hard phase substantially made of titanium carbonitride (TiCN), a solid solution phase made of a composite carbonitride containing titanium and tungsten, and a bonding phase mainly composed of iron group elements such as cobalt and nickel.

[0003] Japanese Patent Publication No. 2013-010997

[0004] The cermet member of this disclosure comprises a substrate and a coating layer covering at least a portion of the surface of the substrate. The substrate has a plurality of hard phases containing TiCN as a main component, a plurality of solid solution phases containing Ti and W, and a plurality of bonding phases containing at least one element among Ni and Co. In a cross-section including the interface between the substrate and the coating layer, within a length of 10 μm of the interface, the maximum length of the first portion in contact between the hard phase and the coating layer is smaller than the average value of the particle sizes of the plurality of solid solution phases.

[0005] Figure 1 is a perspective view showing an example of a cermet member according to the embodiment. Figure 2 is a side cross-sectional view showing an example of a cermet member according to the embodiment. Figure 3 is a schematic scanning electron microscope image showing a cross-section of a cermet member according to the embodiment. Figure 4 is a schematic scanning electron microscope image showing a cross-section of a cermet member in a reference example. Figure 5 is a schematic scanning electron microscope image showing a cross-section of a cermet member according to the embodiment, and is a further enlarged view of a narrower area than that in Figure 3. Figure 6 is a front view showing an example of a cutting tool according to the embodiment. Figure 7 is a scanning electron microscope image showing a cross-section of a cermet member of sample No. 18.

[0006] The embodiments for implementing the cermet members, cutting inserts, and cutting tools according to this disclosure (hereinafter referred to as "embodiments") will be described in detail below with reference to the drawings. Note that these embodiments do not limit the cermet members, cutting inserts, and cutting tools according to this disclosure. Each embodiment can be combined as appropriate, provided that the processing content is not inconsistent. The same parts are denoted by the same reference numerals in the following embodiments, and redundant descriptions are omitted.

[0007] An example of a cutting tool used when machining a workpiece is the cutting tool described in Patent Document 1. The cutting tool described in Patent Document 1 comprises a substrate made of cermet and a coating layer covering the surface of the substrate. The substrate also has a hard phase substantially made of titanium carbonitride (TiCN), a solid solution phase made of a composite carbonitride containing titanium and tungsten, and a bonding phase mainly composed of iron group elements such as cobalt and nickel.

[0008] However, conventional technology still had room for improvement in terms of enhancing the bonding between the substrate and the coating layer. Therefore, there is a need for a technology that can solve the above problems and improve the bonding between the substrate and the coating layer.

[0009] <Cermet Member> Figure 1 is a perspective view showing an example of a cermet member 1 according to the embodiment. Figure 2 is a side cross-sectional view showing an example of a cermet member 1 according to the embodiment. The cermet member 1 is also an example of a cutting insert. As shown in Figures 1 and 2, the cermet member 1 according to the embodiment may include a substrate 2 and a coating layer 3.

[0010] The base body 2 may have a hexahedron shape in which the top and bottom surfaces (the surfaces intersecting the Z-axis as shown in Figure 1) are parallelograms. One corner of the base body 2 may function as a cutting edge. This cutting edge may include a first surface (e.g., the top surface) and a second surface (e.g., the side surface) connected to this first surface.

[0011] In this embodiment, the first surface may function as a "scooping surface" for scooping up chips generated by cutting, and the second surface may function as a "relief surface". Cutting edges may be located on at least a portion of the ridge where the first and second surfaces intersect. The cermet member 1 may cut the workpiece by applying these cutting edges to the workpiece.

[0012] A through-hole 21 may be located in the center of the base body 2, penetrating it vertically. In this case, a screw 75 (see Figure 6) for attaching the cermet member 1 to a holder 70 (see Figure 6), which will be described later, may be inserted into the through-hole 21.

[0013] The substrate 2 may be composed of a cermet. This cermet may contain Ti (titanium) and W (tungsten), as well as at least one of Co (cobalt) and Ni (nickel). The detailed composition of the substrate 2 will be described later.

[0014] The coating layer 3 may cover at least a portion of the surface of the substrate 2. Although the example in Figure 2 shows the case where the coating layer 3 completely covers the surface of the substrate 2, the coating layer 3 does not necessarily need to cover the entire surface of the substrate 2.

[0015] The coating layer 3 may have functions to improve the wear resistance and heat resistance of the substrate 2. For example, if the coating layer 3 is located on the first surface of the substrate 2, the wear resistance and heat resistance of the first surface will be improved. Also, if the coating layer 3 is located on the second surface of the substrate 2, the wear resistance and heat resistance of the second surface will be improved.

[0016] The coating layer 3 may be composed of, for example, at least one metallic element from among the Group 4, Group 5, and Group 6 elements of the periodic table, Al (aluminum), and Si (silicon), and at least one nonmetallic element from among C (carbon), N (nitrogen), and O (oxygen).

[0017] With this configuration, the oxidation resistance of the coating layer 3 is improved, and therefore the wear resistance of the coating layer 3 is further improved. The coating layer 3 may be one layer or two or more layers.

[0018] Figure 3 is a schematic scanning electron microscope image of a cross-section of the cermet member 1 according to the embodiment. As shown in Figure 3, the substrate 2 composed of cermet may have a plurality of hard phases 5, a plurality of solid solution phases 6, and a plurality of binding phases 7.

[0019] In the substrate 2, the hard phase 5 and the solid solution phase 6 may be bonded to each other by the bonding phase 7, or the hard phases 5 may be directly bonded to each other by the bonding phase 7. Alternatively, in the substrate 2, the hard phases 5 may be indirectly bonded to each other by the bonding phase 7 via the solid solution phase 6.

[0020] Furthermore, in the substrate 2, the hard phases 5 may be directly bonded to each other without the solid solution phase 6 or the bonding phase 7, and the solid solution phases 6 may be directly bonded to each other without the hard phase 5 or the bonding phase 7.

[0021] The hard phase 5 may contain Ti. The hard phase 5 may contain at least one compound from among Ti carbides, nitrides, and carbonitrides. The hard phase 5 may contain TiCN (titanium carbonitride) as a main component. In this disclosure, "main component" means, for example, that the ratio of the mass of the component to the total mass of the components constituting the phase in question is 55% by mass or more.

[0022] The hard phase 5 may contain Ti, W, and at least one element from among the Group 4, Group 5, and Group 6 elements of the periodic table other than Ti and W (hereinafter also referred to as "Group 4 to Group 6 elements"). The Ti content in the metallic elements contained in the hard phase 5 may be 80% by mass or more. The total content of W and Group 4 to Group 6 elements in the metallic elements contained in the hard phase 5 may be 1% by mass to 15% by mass.

[0023] The hard phase 5 may contain at least one element from Co and Ni as the remainder. The total content of Ti, W, group 4 to 6 elements, Co, and Ni in the metallic elements contained in the hard phase 5 may be 100% by mass.

[0024] The solid solution phase 6 may contain Ti and W. The solid solution phase 6 may be a solid solution containing at least one compound from among Ti carbides, nitrides and carbonitrides, at least one compound from among W carbides, nitrides and carbonitrides, and at least one compound from among carbides, nitrides and carbonitrides of at least one element from Group 4 to 6.

[0025] The solid solution phase 6 may contain Ti, W, at least one element from groups 4 to 6, and at least one element from Ni and Co.

[0026] The Ti content in the metal elements contained in the solid solution phase 6 may be 30% to 70% by mass. The total content of W and group 4 to 6 elements in the metal elements contained in the solid solution phase 6 may be 30% to 70% by mass.

[0027] The total content of Ni and Co in the metal elements contained in the solid solution phase 6 may be 0% to 3% by mass. The total content of Ti, W, group 4 to 6 elements, Co, and Ni in the metal elements contained in the solid solution phase 6 may be 100% by mass.

[0028] The bonded phase 7 may contain at least one element from Ni and Co. The bonded phase 7 may contain at least one element from Ni and Co, and W.

[0029] As shown in Figure 3, the cross-section of the substrate 2 in this disclosure may be any cross-section that allows confirmation of the interface 10 between the substrate 2 and the coating layer 3, as well as confirmation of a plurality of hard phases 5, a plurality of solid solution phases 6, and a plurality of binding phases 7. The cross-section of the substrate 2 in this disclosure may also be a backscattered electron image of the cross-section captured by a scanning electron microscope (SEM).

[0030] In this backscattered electron image, the hard phase 5 is observed to be, for example, darker than the solid solution phase 6. The binding phase 7 is observed to be, for example, whiter than the solid solution phase 6. Furthermore, the solid solution phase 6 is observed to be a gray color between the color of the hard phase 5 and the color of the binding phase 7. The cross-section of the substrate 2 in this disclosure may be, for example, a cross-section with a size of 100 μm × 100 μm.

[0031] To distinguish each of the multiple hard phases 5, for example, electron backscatter diffraction (EBSD) in a scanning electron microscope can be used.

[0032] Specifically, an electron beam is irradiated onto the cross-section of the substrate 2 using a scanning electron microscope, and the reflected electrons from the cross-section of the substrate 2 are received by a fluorescent screen to obtain a Kikuchi pattern that reflects the crystal structure of each of the multiple hard phases 5. By obtaining information on the crystal orientation of each of the multiple hard phases 5 from this pattern, each of the multiple hard phases 5 can be identified.

[0033] Similarly, to distinguish between each of the multiple solid solution phases 6 or the multiple bonded phases 7, for example, electron backscatter diffraction in a scanning electron microscope can be used.

[0034] Specifically, a Kikuchi pattern reflecting the crystal structure of each of the multiple solid solution phases 6 or multiple bonding phases 7 is obtained by irradiating the cross-section of the substrate 2 with an electron beam using a scanning electron microscope and receiving the reflected electrons from the cross-section of the substrate 2 with a fluorescent screen.

[0035] By obtaining information about the crystal orientation of each of the multiple solid solution phases 6 or multiple bonding phases 7 from this pattern, each of the multiple solid solution phases 6 or multiple bonding phases 7 can be identified.

[0036] In this embodiment, the maximum length L1 of the first portion 11 in which the hard phase 5 and the coating layer 3 come into contact within a length of 10 μm of the interface 10 in the cross-section of the substrate 2 may be smaller than the average value of the particle sizes of the multiple solid solution phases 6.

[0037] Furthermore, in the present disclosure, the length L1 of the first portion 11 and the grain size of the solid solution phase 6 can be calculated, for example, by applying known image processing to a reflected electron image of the cermet member 1. Also, in the present disclosure, for example, the diameter of a circumscribed circle in contact with the grain boundary of the solid solution phase 6 can be regarded as the grain size of said solid solution phase 6.

[0038] Fig. 4 is a diagram schematically showing a scanning electron micrograph of a cross-section of the cermet member 1 in a reference example. As shown in Fig. 4, when the maximum value of the length L1 of this first portion 11 is large, since the adhesion of the hard phase 5 to the coating layer 3 is smaller than the adhesion of other phases (the solid solution phase 6 and the binder phase 7) to the coating layer 3, cracks may easily propagate at the interface 10.

[0039] This is because the toughness of the hard phase 5 containing TiCN as a main component is lower than the toughness of the aforementioned other phases, and when the coating layer 3 deforms, the hard phase 5 is less likely to follow the deformation of the coating layer 3, and the adhesion tends to be relatively small.

[0040] On the other hand, in the embodiment, as shown in Fig. 3, by reducing the maximum value of the length L1 of the first portion 11, the propagation of cracks at the interface 10 can be reduced or prevented. Therefore, according to the embodiment, the bonding property between the base body 2 and the coating layer 3 can be improved.

[0041] In particular, since Ni and Co contained in the binder phase 7 have excellent adhesion to the coating layer 3, when the solid solution phase 6 contains at least one element selected from Ni and Co as described above, the bonding property between the base body 2 and the coating layer 3 can be improved.

[0042] Furthermore, in the embodiment, the maximum value of the length L1 of the first portion 11 where the hard phase 5 is in contact with the coating layer 3 within a range of 10 µm length of the interface 10 in a cross-section of the base body 2 may be 0.5 µm or less.

[0043] Thereby, the propagation of cracks at the interface 10 can be further reduced or prevented. Therefore, according to the embodiment, the bonding property between the base body 2 and the coating layer 3 can be further improved.

[0044] Furthermore, in this embodiment, the total length L1 of the first portion 11 within a length of 10 μm of the interface 10 in the cross-section of the substrate 2 may be smaller than the total length L2 of the second portion 12 where the solid solution phase 6 and the coating layer 3 are in contact.

[0045] The length L2 of the second portion 12 can be calculated, for example, by applying known image processing to the backscattered electron image of the cermet member 1.

[0046] In this way, by shortening the total length L1 of the first portion 11, the propagation of cracks at the interface 10 can be further reduced or prevented. Therefore, according to this embodiment, the bonding between the substrate 2 and the coating layer 3 can be further improved.

[0047] Furthermore, in this embodiment, the total length L1 of the first portion 11 within a length range of 10 μm of the interface 10 in the cross-section of the substrate 2 may be 1 / 3 or less of the length of the interface 10.

[0048] This makes it possible to further reduce or prevent crack propagation at the interface 10. Therefore, according to this embodiment, the bonding between the substrate 2 and the coating layer 3 can be further improved.

[0049] Furthermore, in this embodiment, within a length of 10 μm of the interface 10 in the cross-section of the substrate 2, the second portion 12 may be adjacent to the first portion 11. That is, the hard phase 5 in contact with the interface 10 may be adjacent to the solid solution phase 6 instead of the binding phase 7.

[0050] Thus, by placing the solid solution phase 6, which has a similar composition to the hard phase 5 and therefore a small difference in thermal expansion coefficient, adjacent to the hard phase 5, the propagation of cracks at the interface 10 can be further reduced or prevented. Therefore, according to this embodiment, the bonding between the substrate 2 and the coating layer 3 can be further improved.

[0051] Furthermore, in this embodiment, the length L1 of the first portion 11 may be shorter than the length L2 of the second portion 12 adjacent to the first portion 11. This further reduces or prevents crack propagation at the interface 10. Therefore, according to this embodiment, the bonding between the substrate 2 and the coating layer 3 can be further improved.

[0052] Furthermore, in this embodiment, the hard phase 5 may be separated from the binder phase 7 at the first portion 11. In the example shown in Figure 3, the hard phase 5 is separated from the binder phase 7 at the first portion 11 because the second portion 12 is in contact with both ends of the first portion 11. This positioning of the hard phase 5 further reduces crack propagation at the interface 10.

[0053] Furthermore, in the embodiment, as shown in the example in Figure 5, the width W1 of the hard phase 5 located in the first portion 11 may be greater than the length L1 of the first portion 11. In other words, the hard phase 5 may have a width W1 greater than the length L1 of the first portion 11 inward from the first portion 11, which is the interface with the coating layer 3.

[0054] If the hard phase 5 has the above configuration, even if the hard phase 5 separates from the solid solution phase 6, it is difficult for the hard phase 5 to move because it is surrounded by the solid solution phase 6. Therefore, even if the hard phase 5 separates from the solid solution phase 6 and the coating layer 3, the position of the hard phase 5 is easily fixed, and cracks originating from the hard phase 5 are unlikely to propagate.

[0055] Furthermore, in the embodiment, the total length of the portion where the binding phase 7 and the coating layer 3 are in contact, i.e., the interface between the binding phase 7 and the coating layer 3, within a length of 10 μm in the cross-section of the substrate 2, may be greater than the total length of the first portion 11. When the interface between the substrate 2 and the coating layer 3 has the above configuration, the bonding between the substrate 2 and the coating layer 3 is improved.

[0056] Furthermore, in the embodiment, the number of contact points between the bonding phase 7 and the coating layer 3 within a length of 10 μm of the interface 10 in the cross-section of the substrate 2 may be greater than the number of first parts 11. For example, in the example shown in Figure 3, the number of contact points between the bonding phase 7 and the coating layer 3 is 5, and the number of first parts 11 is 3.

[0057] As described above, the bonding between the substrate 2 and the coating layer 3 is improved when the sum of the lengths of the interface between the bonding phase 7 and the coating layer 3 is greater than the sum of the lengths of the first portion 11. However, the bonding between the substrate 2 and the coating layer 3 can also be improved by having a relatively large number of contact points between the bonding phase 7 and the coating layer 3.

[0058] Furthermore, when the number of contact points between the bonding phase 7 and the coating layer 3 is relatively large, variations in bonding strength between the bonding phase 7 and the coating layer 3 can be reduced. As a result, the occurrence and propagation of cracks at the interface 10 can be efficiently reduced.

[0059] <Manufacturing Process> Next, an example of the manufacturing process for the cermet member 1 according to the embodiment will be described.

[0060] First, several raw material powders are prepared. Specifically, TiCN powder with an average particle size of 0.1 μm to 1.2 μm is prepared. Note that the average particle size of the TiCN powder may be 0.2 μm to 0.8 μm. Furthermore, the average particle size of the TiCN powder may be 0.5 μm or less. By micronizing the TiCN powder in this way, it is possible to stably reduce the maximum value of the length L1 of the first part 11 to 0.5 μm or less. In addition, WC powder with an average particle size of 0.1 μm to 2.5 μm is prepared. Also, Cr with an average particle size of 2 μm to 4 μm is prepared. ３ C ２ Prepare the powder.

[0061] Furthermore, the above-mentioned TiCN, WC, and Cr ３ C ２ Prepare a powder of at least one compound from among carbide powders, nitride powders, and carbonitride powders of at least one element from the Group 4, Group 5, and Group 6 elements of the periodic table, excluding the elements in question. Also, prepare a metal W powder and WC with an average particle size of 3 μm to 15 μm. １－ｘ(0 < x ≦ 1) powder, at least one powder thereof is prepared.

[0062] Next, various raw material powders described so far are mixed to prepare a primary mixed powder. In this preparation step, the aforementioned metal W powder and WC １－ｘ (0 < x ≦ 1) powder, the content of at least one powder thereof may be 1% by mass to 20% by mass relative to the total mass of the primary mixed powder.

[0063] In addition, carbon powder may be added to the primary mixed powder, and a predetermined amount of MnCO ３ powder with an average particle diameter of 0.5 μm to 5 μm may be added.

[0064] In an embodiment, except for TiCN, WC and Cr ３ C ２ , as the powder of at least one compound selected from carbide powders, nitride powders and carbonitride powders of at least one element selected from group 4 elements, group 5 elements and group 6 elements of the periodic table, TiC powder, TiN powder, NbC powder, Mo ２ 2C powder, TaC powder, VC powder or ZrC powder with an average particle diameter of 0.1 μm to 3 μm may be applied.

[0065] Next, an organic binder, a solvent and the like are added to the primary mixed powder, and the mixture is further pulverized and mixed using a ball mill, vibration mill, jet mill, attritor mill or the like to prepare a secondary mixed powder. When an attritor mill is used, non-metallic powders are pulverized to have a smaller particle size, while metallic powders have high ductility and thus tend to be difficult to pulverize.

[0066] Next, at least one powder selected from predetermined amount of metallic Co powder and metallic Ni powder with an average particle diameter of 0.5 μm to 5 μm is added to the secondary mixed powder. Then, the mixture is pulverized and mixed by the known method described above, and further dried to prepare a tertiary mixed powder.

[0067] As described above, TiCN powder with an average particle size of 0.5 μm or less may be prepared as the raw material powder, and the TiCN powder may be pulverized by the following process. Specifically, in the step of preparing the secondary mixed powder and / or the step of preparing the tertiary mixed powder, the primary mixed powder may be pulverized and mixed until the average particle size of the TiCN powder is 0.5 μm or less.

[0068] Next, this tertiary mixed powder is used to form a molded body of a predetermined shape by known molding methods such as press molding, extrusion molding, or injection molding.

[0069] Next, the molded body is fired in a vacuum or inert gas atmosphere. In this embodiment, for example, the substrate 2 with the predetermined structure described above can be produced by firing the molded body in the following steps: (a) Heat from room temperature to 450°C and maintain the 450°C temperature for 0.5 to 2 hours. (b) Heat further from 450°C to a temperature T1 of 1000°C to 1100°C. (c) Heat from firing temperature T1 to firing temperature T2 of 1500°C to 1600°C in a vacuum or in an inert gas atmosphere of 30 Pa to 20000 Pa. (d) Maintain the firing temperature T2 for 0.5 to 2 hours in a vacuum or in an inert gas atmosphere of 30 Pa to 20000 Pa. (e) Cool down to room temperature in a vacuum or in an inert gas atmosphere of 30 Pa to 20000 Pa at a cooling rate of 5°C / min to 40°C / min.

[0070] In this case, the firing conditions may be set such that the maximum length of the hard phase 5 exposed on the surface of the molded body is smaller than the average value of the particle sizes of the multiple solid solution phases 6. Specifically, when firing the molded body, firing conditions may be set to promote grain growth of the solid solution phases 6 such that the average value of the particle sizes of the multiple solid solution phases 6 is larger than the maximum length of the hard phase 5 exposed on the surface of the molded body.

[0071] Furthermore, when firing the molded body, firing conditions may be set to suppress grain growth of the hard phase 5 so that the maximum length of the hard phase 5 exposed on the surface of the molded body is smaller than the average value of the particle sizes of the multiple solid solution phases 6. In this way, the firing conditions can be set so that the maximum length of the hard phase 5 exposed on the surface of the molded body is smaller than the average value of the particle sizes of the multiple solid solution phases 6, and the method is not limited to specific firing conditions.

[0072] Subsequently, the cermet member 1 according to the embodiment is completed by forming a coating layer 3 on the surface of the obtained substrate 2. The coating layer 3 can be a so-called hard film, and can be formed, for example, by the PVD method or the CVD method. The coating layer 3 may be a single layer film or a laminated film.

[0073] <Cutting Tool> Next, the configuration of a cutting tool equipped with the cermet member 1 described above will be explained with reference to Figure 6. Figure 6 is a front view showing an example of a cutting tool 100 according to the embodiment. As shown in Figure 6, the cutting tool 100 according to the embodiment may include a cermet member 1 which is a cutting insert and a holder 70 for fixing the cermet member 1.

[0074] The holder 70 may be a rod-shaped member extending from the tip (upper end in Figure 6) to the rear end (lower end in Figure 6). The holder 70 is made of, for example, steel or cast iron. In particular, it is preferable to use steel, which has high toughness among these materials.

[0075] The holder 70 may have a pocket 73 located at the end on the tip side. The pocket 73 is the part into which the cermet member 1 is mounted, and may have a seating surface that intersects with the rotational direction of the workpiece, and a restraining side surface that is inclined with respect to the seating surface. The seating surface may be provided with a screw hole for screwing in a screw 75, which will be described later.

[0076] The cermet member 1 is located in the pocket 73 of the holder 70 and may be attached to the holder 70 by a screw 75. For example, the screw 75 is inserted into the through hole 21 (see Figure 1) of the cermet member 1, and the tip of the screw 75 is inserted into a screw hole formed in the seating surface of the pocket 73 and screwed in. In this way, the cermet member 1 is attached to the holder 70 such that the cutting edge portion protrudes outward from the holder 70.

[0077] In this embodiment, a cutting tool 100 used in so-called turning operations is illustrated. Examples of turning operations include internal diameter machining, external diameter machining, or grooving operations. However, the cutting tool is not limited to those used in turning operations. For example, a cermet member 1 may be used as a cutting tool for milling operations.

[0078] Examples of cutting tools used in milling include milling cutters such as flat milling cutters, face milling cutters, side milling cutters, or groove milling cutters, and end mills such as single-flute end mills, multi-flute end mills, tapered end mills, or ball end mills.

[0079] The embodiments of this disclosure will be described below in detail. However, this disclosure is not limited to the embodiments shown below.

[0080] Following the manufacturing process of the cermet member 1 according to the embodiment described above, cermet members 1 of samples No. 1 to 26 were manufactured with different compositions and crystal structures as shown in Table 1. Next, the obtained cermet members 1 were cut, the exposed cross-sections were polished, and the polished surfaces were photographed with a scanning electron microscope. Figure 7 shows a scanning electron microscope image of the cross-section of cermet member 1 of sample No. 18.

[0081] As shown in Figure 7, it was confirmed that the substrate 2 of the cermet member 1 of sample No. 18 contains a plurality of hard phases 5 shown in black, a plurality of solid solution phases 6 shown in gray, and a plurality of binding phases 7 shown in grayish-white.

[0082] Furthermore, it was confirmed that the substrate 2 of the cermet members 1 of the other samples No. 1 to 17 and 19 to 26 also contained a plurality of hard phases 5, a plurality of solid solution phases 6, and a plurality of binding phases 7.

[0083] Next, scanning electron microscope images of cermet members 1 of samples No. 1 to 26 were used to evaluate the average particle size of the solid solution phase 6 and the maximum length L1 (see Figure 3) of the first portion 11 (see Figure 3) within a 10 μm length range of the interface 10. The results are shown in Table 1.

[0084]

[0085] As shown in Table 1, in the cermet members 1 of samples No. 2 to 26, it was confirmed that the maximum length L1 of the first portion 11 where the hard phase 5 and the coating layer 3 come into contact within a length of 10 μm of the interface 10 was smaller than the average value of the particle sizes of the multiple solid solution phases 6.

[0086] On the other hand, in the cermet member 1 of sample No. 1, it was confirmed that the maximum length L1 of the first portion 11 where the hard phase 5 and the coating layer 3 come into contact within a length of 10 μm of the interface 10 was greater than the average value of the particle sizes of the multiple solid solution phases 6.

[0087] Furthermore, as shown in Table 1, it was confirmed that in the cermet members 1 of samples No. 4 to 26, the maximum value of the length L1 of the first portion 11 was 0.5 μm or less within the 10 μm length range of the interface 10.

[0088] Next, scanning electron microscope images of cermet members 1 of samples No. 1 to 26 were used to evaluate the ratio of the total length L1 of the first portion 11 to the total length L2 of the second portion 12 within a 10 μm length range of the interface 10.

[0089] Furthermore, scanning electron microscope images of the cermet members 1 of samples No. 1 to 26 were used to evaluate the ratio of the total length L1 of the first portion 11 to the length of the interface 10 within a 10 μm length range of the interface 10.

[0090] Furthermore, scanning electron microscope images of the cermet members 1 of samples No. 1 to 26 were used to evaluate whether the first portion 11 and the second portion 12 were adjacent within a 10 μm length range of the interface 10.

[0091] Furthermore, scanning electron microscope images of cermet members 1 of samples No. 1 to 26 were used to evaluate the ratio of the length L1 of the first portion 11 to the length L2 of the second portion 12 adjacent to the first portion 11 within a 10 μm length range of the interface 10. The results are shown in Table 2.

[0092]

[0093] As shown in Table 2, in the cermet members 1 of samples No. 1 to 6 and 8 to 26, it was confirmed that in the 10 μm length range of the interface 10, the sum of the lengths L1 of the first portion 11 was smaller than the sum of the lengths L2 (see Figure 3) of the second portion 12 (see Figure 3), i.e., "sum of first portion length / sum of second portion length" was less than 1.

[0094] Furthermore, as shown in Table 2, in the cermet members 1 of samples No. 1 to 8 and 10 to 26, it was confirmed that the total length L1 of the first portion 11 was 1 / 3 or less of the length of the interface 10 within a 10 μm length range of the interface 10.

[0095] Furthermore, as shown in Table 2, in the cermet members 1 of samples No. 1 to 9 and 11 to 26, it was confirmed that in the 10 μm length range of the interface 10, all first portions 11 were adjacent to the second portion 12.

[0096] Furthermore, as shown in Table 2, it was confirmed that in the cermet members 1 of samples No. 1 to 10 and 12 to 26, the length L1 of the first portion 11 is shorter than the length L2 of the second portion 12 adjacent to the first portion 11, that is, "length of the first portion / length of the adjacent second portion" is less than 1.

[0097] Next, bonding tests were conducted on the cermet member 1 in the embodiment and the cermet member 1 in the reference example, specifically on the bonding between the substrate 2 and the coating layer 3. Specifically, fracture resistance tests and wear resistance tests were performed during turning to evaluate the bonding between the substrate 2 and the coating layer 3. The conditions for the fracture resistance test and wear resistance test are as follows.

[0098] <Fracture Resistance Test (Turning)> Workpiece material: S45C φ200 (4 grooves with a width of 25 mm) Cutting speed: 250 m / min Feed rate: 0.25 mm / rev Depth of cut: 1.0 mm Cutting condition: Wet Evaluation method: Number of impacts until fracture occurs (times)

[0099] <Wear Resistance Test (Turning)> Workpiece Material: SCM435φ100 Cutting Speed: 250 m / min Feed Rate: 0.2 mm / rev Depth of Cut: 1.0 mm Cutting Condition: Wet Evaluation Method: Nose wear amount during 30 min machining

[0100] As shown in Table 2, it was confirmed that the cermet members 1 of samples No. 2 to 26 showed improved bonding between the substrate 2 and the coating layer 3 compared to the cermet member 1 of sample No. 1, resulting in favorable results in both the fracture resistance test and the abrasion resistance test.

[0101] As described above, in the cermet member 1 according to the embodiment, in the cross-section including the interface 10 between the substrate 2 and the coating layer 3, the maximum length L1 of the first portion 11 in contact with the hard phase 5 and the coating layer 3 within a length of 10 μm of the interface 10 is smaller than the average value of the particle sizes of the multiple solid solution phases 6. This improves the bonding between the substrate 2 and the coating layer 3.

[0102] The shape of the cermet member 1 shown in Figure 1 is merely an example and does not limit the shape of the cermet member according to this disclosure. The cermet member according to this disclosure may, for example, have a rod-shaped body having a rotation axis and extending from a tip to a rear end, a cutting edge located at the first end of the body, and a groove extending spirally from the cutting edge toward the second end of the body.

[0103] Furthermore, although the above embodiment described an example of applying the cermet member 1 to a cutting tool 100, the application field of the cermet member according to this disclosure is not limited to cutting tools.

[0104] Although the present disclosure has been described in detail above, this disclosure is not limited to the embodiments described above, and various modifications and improvements are possible without departing from the gist of this disclosure.

[0105] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. Indeed, the embodiments described above can be embodied in a variety of forms. Furthermore, the embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims.

[0106] Furthermore, this technology can take the following configurations: (1) A cermet member comprising: a substrate; and a coating layer covering at least a portion of the surface of the substrate, wherein the substrate comprises: a plurality of hard phases containing TiCN as a main component; a plurality of solid solution phases containing Ti and W; and a plurality of bonding phases containing at least one element among Ni and Co, wherein the maximum length of the first portion in which the hard phases and the coating layer are in contact within a 10 μm length range of the interface in a cross-section including the interface between the substrate and the coating layer is smaller than the average value of the particle sizes of the plurality of solid solution phases. (2) The cermet member according to (1) above, wherein the total length of the first portion in the range is smaller than the total length of the second portion in which the solid solution phases and the coating layer are in contact. (3) The cermet member according to (1) or (2) above, wherein the total length of the first portion in the range is 1 / 3 or less of the length of the interface. (4) The cermet member according to any one of (1) to (3), wherein, within the range, the maximum length of the first portion is 0.5 μm or less. (5) The cermet member according to any one of (1) to (4), wherein, within the range, the first portion is adjacent to a second portion in which the solid solution phase and the coating layer are in contact. (6) The cermet member according to (5), wherein the length of the first portion is shorter than the length of the second portion adjacent to the first portion. (7) The cermet member according to any one of (1) to (6), wherein the hard phase is separated from the binder phase in the first portion. (8) The cermet member according to any one of (1) to (7), wherein the width of the hard phase located in the first portion is greater than the length of the first portion. (9) The cermet member according to any one of (1) to (8), wherein, within the range, the sum of the lengths of the portions in contact with the binder phase and the coating layer is greater than the sum of the lengths of the first portion. (10) A cermet member according to any one of (1) to (9) above, wherein the number of parts in which the bonding phase and the coating layer are in contact within the range is greater than the number of the first parts. (11) A cutting insert comprising a cermet member according to any one of (1) to (10) above, wherein the substrate has a cutting edge.(12) A cutting tool comprising: a holder extending from a tip to a rear end and having a pocket located on the side of the tip; and the cutting insert described in (11) located in the pocket.

[0107] 1. Cermet component (an example of a cutting insert) 2. Substrate 3. Coating layer 5. Hard phase 6. Solid solution phase 7. Bonding phase 10. Interface 11. First part 12. Second part 70. Holder 73. Pocket 100. Cutting tool

Claims

1. A cermet member comprising: a substrate; and a coating layer covering at least a portion of the surface of the substrate, wherein the substrate comprises: a plurality of hard phases containing TiCN as a main component; a plurality of solid solution phases containing Ti and W; and a plurality of bonding phases containing at least one element among Ni and Co, wherein the maximum length of the first portion in which the hard phases and the coating layer are in contact within a 10 μm length range of the interface in a cross-section including the interface between the substrate and the coating layer is smaller than the average value of the particle sizes of the plurality of solid solution phases.

2. The cermet member according to claim 1, wherein, within the range, the total length of the first portion is less than the total length of the second portion in contact with the solid solution phase and the coating layer.

3. The cermet member according to claim 1 or 2, wherein, within the range, the total length of the first portion is 1 / 3 or less of the length of the interface.

4. The cermet member according to any one of claims 1 to 3, wherein the maximum length of the first portion within the range is 0.5 μm or less.

5. The cermet member according to any one of claims 1 to 4, wherein, in the range, the first portion is adjacent to a second portion in which the solid solution phase and the coating layer are in contact.

6. The cermet member according to claim 5, wherein the length of the first portion is shorter than the length of the second portion adjacent to the first portion.

7. The cermet member according to any one of claims 1 to 6, wherein the hard phase is separated from the binding phase in the first portion.

8. The cermet member according to any one of claims 1 to 7, wherein the width of the hard phase located in the first portion is greater than the length of the first portion.

9. The cermet member according to any one of claims 1 to 8, wherein, in the range, the total length of the portion where the binding phase and the coating layer are in contact is greater than the total length of the first portion.

10. The cermet member according to any one of claims 1 to 9, wherein the number of contact points between the binding phase and the coating layer within the range is greater than the number of first contact points.

11. A cutting insert comprising a cermet member according to any one of claims 1 to 10, wherein the base body has a cutting edge.

12. A cutting tool comprising: a holder extending from a tip to a rear end and having a pocket located on the side of the tip; and a cutting insert according to claim 11 located in the pocket.

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