Coated cutting tool

Abstract

An unrestricted example of the coated cutting tool of the present invention has a substrate and a coating film located on the substrate. The coated cutting tool has a first surface, a second surface adjacent to the first surface, and a cutting edge located on at least a part of the ridge portion between the first surface and the second surface. The coating film has an AlTiN film containing Ti, Al, and N. Moreover, in the first surface, when the Al / (Al + Ti) at a position 0.1 mm away from the cutting edge is defined as the first Al ratio and the Al / (Al + Ti) at a position 0.2 mm away from the cutting edge is defined as the second Al ratio, the first Al ratio and the second Al ratio are 0.7 or more, and the second Al ratio is greater than the first Al ratio.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of Japanese Patent Application No. 2020 - 006885 filed on January 20, 2020, and incorporates the entire invention of the prior application herein by reference. Technical field

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

[0004] As a coated cutting tool, for example, a surface - coated cutting tool described in Japanese Unexamined Patent Application Publication No. 2013 - 158868 (Patent Document 1) is known. The surface - coated cutting tool (coated cutting tool) described in Patent Document 1 has a hard coating formed by depositing a composite nitride layer of Al and Cr on the surface of a tool substrate. The deposition of the hard coating is carried out by an arc ion plating method, which is a kind of physical vapor deposition (PVD) method. Summary of the invention

[0005] An example of a coated cutting tool of the present invention, which is not limited, has a substrate and a coating film located on the substrate. The coated cutting tool includes: a first face; a second face adjacent to the first face; and an edge located on at least a part of the ridge line portion between the first face and the second face. The coating film includes an AlTiN film containing Ti, Al, and N. Moreover, on the first face, when the Al / (Al + Ti) at a position 0.1 mm from the edge is defined as the first Al ratio and the Al / (Al + Ti) at a position 0.2 mm from the edge is defined as the second Al ratio, the first Al ratio and the second Al ratio are 0.7 or more, and the second Al ratio is greater than the first Al ratio. Description of the drawings

[0006] Figure 1 It is a perspective view showing a coated cutting tool according to an embodiment of the present invention, which is not limited.

[0007] Figure 2 It is Figure 1 An enlarged view of the II - II cross - section of the shown coated cutting tool.

[0008] Figure 3 It is Figure 2 An enlarged view of the periphery of the edge of the shown coated cutting tool. Detailed description of the invention

[0009] <Coated cutting tool>

[0010] Hereinafter, with reference to the accompanying drawings, a coated cutting tool according to an unrestricted embodiment of the present invention will be described in detail. However, the drawings referred to below only schematically show the necessary structures for the purpose of facilitating the description of the embodiments. Therefore, the coated cutting tool can have any structure not shown in the drawings. In addition, the dimensions of the structures in the drawings do not faithfully represent the actual dimensions and dimensional ratios, etc.

[0011] Figures 1 to 3 The exemplified coated cutting tool 1 is a cutting tool (cutting insert) used for machining a workpiece. The coated cutting tool 1 can be applied to, for example, wear-resistant parts such as sliding parts and dies, excavation tools, tools such as cutting tools, and impact-resistant parts, in addition to cutting tools. Further, the use of the coated cutting tool 1 is not limited to the exemplified uses.

[0012] The coated cutting tool 1 can have a substrate 2 and a coating film 3 located on the substrate 2.

[0013] Examples of the material of the substrate 2 include cemented carbide, ceramics, and metals. Examples of the cemented carbide include cemented carbide obtained by binding a hard phase, where the hard phase contains WC (tungsten carbide) and at least one selected from the group of carbides, nitrides, and carbonitrides of metals in Groups 4, 5, and 6 of the periodic table other than WC, and the binding phase contains iron-based metals such as Co (cobalt) and Ni (nickel). In addition, other examples of the cemented carbide include Ti-based cermets. Examples of the ceramics include Si3N4 (silicon nitride), Al2O3 (aluminum oxide), diamond, and cBN (cubic boron nitride). Examples of the metals include carbon steel, high-speed steel, and alloy steel. Further, the material of the substrate 2 is not limited to the exemplified materials.

[0014] The coating film 3 can cover the entire surface 4 of the substrate 2, or can cover only a part thereof. When the coating film 3 covers only a part of the surface 4 of the substrate 2, the coating film 3 can be said to be located on at least a part of the substrate 2.

[0015] Figures 1 to 3 The exemplified coating film 3 can be formed by chemical vapor deposition (CVD). In other words, Figures 1 to 3 The exemplified coating film 3 can be a CVD film.

[0016] The thickness of the coating film 3 can be set to, for example, 1 to 20 μm. The thickness of the coating film 3 can be measured, for example, by cross-sectional measurement using a scanning electron microscope (SEM) or the like.

[0017] The coated cutting tool 1 may include: a first surface 5 (upper surface); a second surface 6 (side surface) adjacent to the first surface 5; and a cutting edge 7 located on at least a part of the ridge portion between the first surface 5 and the second surface 6. The cutting edge 7 may be located on a part of the ridge portion, or may be located on the entire ridge portion.

[0018] The first surface 5 may be a rake face. The entire surface of the first surface 5 may be a rake face, or a part of it may be a rake face. For example, the area of the first surface 5 along the cutting edge 7 may be a rake face.

[0019] The second surface 6 may be a flank face. The entire surface of the second surface 6 may be a flank face, or a part of it may be a flank face. For example, the area of the second surface 6 along the cutting edge 7 may be a flank face.

[0020] Also, Figure 1 The illustrated coated cutting tool 1 is in the shape of a quadrilateral plate, but the shape of the coated cutting tool 1 is not limited to this shape. For example, Figure 1 The illustrated first surface 5 is quadrilateral, but there is no problem even if the first surface 5 is not quadrilateral but triangular, hexagonal, or the like.

[0021] The size of the coated cutting tool 1 is not particularly limited. For example, in Figure 1 the illustrated coated cutting tool 1, the length of one side of the first surface 5 can be set to about 1 to 20 mm. In addition, the height from the first surface 5 to the surface (lower surface) on the opposite side of the first surface 5 can be set to about 5 to 20 mm.

[0022] Here, the coating film 3 may include an AlTiN (aluminum titanium nitride) film containing Ti (titanium), Al (aluminum), and N (nitrogen). And, as Figure 3 a non-limiting example shown, in the first surface 5, when the Al / (Al + Ti) at the position P1 which is 0.1 mm away from the cutting edge 7 is defined as the first Al ratio, and the Al / (Al + Ti) at the position P2 which is 0.2 mm away from the cutting edge 7 is defined as the second Al ratio, the first Al ratio and the second Al ratio may be 0.7 or more. In addition, the second Al ratio is greater than the first Al ratio.

[0023] According to the above structure, in the part of the position P1 close to the cutting edge 7, the Al content is relatively small, so the toughness is excellent. In addition, in the part of the position P2 farther from the cutting edge 7 than the position P1, since the Al content is relatively large, it has high hardness and high oxidation resistance. Therefore, the coated cutting tool 1 having these structures has a long service life.

[0024] In the second surface 6, when the Al / (Al + Ti) at the position P3 which is 0.1 mm away from the cutting edge 7 is defined as the third Al ratio, and the Al / (Al + Ti) at the position P4 which is 0.2 mm away from the cutting edge 7 is defined as the fourth Al ratio, the third Al ratio and the fourth Al ratio can be 0.7 or more. Additionally, the fourth Al ratio can be greater than the third Al ratio. When these configurations are satisfied, in addition to the first surface 5, the same effects as the first surface 5 can also be obtained on the second surface 6, and thus the coating tool 1 has a longer life.

[0025] The first Al ratio can be greater than the third Al ratio. Additionally, the second Al ratio can be greater than the fourth Al ratio. In other words, it can be the second Al ratio > the first Al ratio > the fourth Al ratio > the third Al ratio. When these configurations are satisfied, it is easy to obtain the effects of suppressing both crater wear and flank wear.

[0026] The first Al ratio and the second Al ratio can be 0.7 or more and 0.95 or less. Additionally, the third Al ratio and the fourth Al ratio can be 0.7 or more and 0.95 or less. When the first Al ratio and the second Al ratio are 0.85 or more and 0.95 or less, and the third Al ratio and the fourth Al ratio are 0.85 or more and 0.95 or less, the coating tool 1 has a longer life. The first to fourth Al ratios can be the atomic ratio-based content ratios of Al relative to the total of Al and Ti. The first to fourth Al ratios can be measured, for example, by energy dispersive X-ray analysis (EDS) method.

[0027] The thickness of the AlTiN film can be set to 1 to 20 μm, for example. Also, the coating film 3 can include other films in addition to the AlTiN film.

[0028] <Manufacturing method of the coating tool>

[0029] Next, taking the case of manufacturing the coating tool 1 as an example, the manufacturing method of the coating tool according to an unrestricted embodiment of the present invention will be described.

[0030] Taking the case of manufacturing the substrate 2 containing cemented carbide as the substrate 2 as an example. First, metal powder, carbon powder, etc. can be appropriately added and mixed in inorganic powders such as metal carbides, nitrides, carbonitrides, oxides, etc. that can form the substrate 2 by firing, and formed into a prescribed tool shape by known forming methods such as stamping, casting, extrusion, cold isostatic pressing, etc. Thereafter, the obtained formed body is fired in a vacuum or a non-oxidizing atmosphere, and thus the substrate 2 formed of cemented carbide can be obtained. Grinding and honing can also be performed on the surface 4 of the substrate 2.

[0031] Next, a coating film 3 can be formed on the surface 4 of the obtained substrate 2 by CVD method to obtain a coated cutting tool 1. As the film formation conditions of the coating film 3 having an AlTiN film, for example, the following conditions can be cited: using a mixed gas having a composition containing 0.05 to 0.5 vol% of TiCl4 (titanium tetrachloride) gas, 0.2 to 2.0 vol% of AlCl3 (aluminum trichloride) gas, 3 to 10 vol% of NH3 (ammonia) gas, and the balance being composed of H2 (hydrogen) gas, and setting the film formation temperature to 700 to 900 °C and the pressure to 1 to 10 kPa.

[0032] Here, if the flow rate of the mixed gas during film formation is higher than the general flow rate, the composition difference of the coating film 3 (AlTiN film) can be caused. As a result, it is easy to form the coating film 3 having the above structure. For example, the flow rate of the mixed gas during film formation can be set to 5 to 50 m / s.

[0033] Further, in the obtained coated cutting tool 1, grinding can also be performed on the region including the cutting edge 7. As a result, the region including the cutting edge 7 becomes smooth, and as a result, adhesion of the work material is suppressed and the chipping resistance of the cutting edge 7 is improved.

[0034] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

[0035] Examples

[0036] [Specimen Nos. 1 to 7]

[0037] <Fabrication of Coated Cutting Tool>

[0038] First, a substrate was fabricated. Specifically, for WC powder having an average particle diameter of 1.2 μm, 6 mass% of metal Co powder having an average particle diameter of 1.5 μm, 2.0 mass% of TiC (titanium carbide) powder, and 0.2 mass% of Cr3C2 (chromium carbide) powder were added at a mass% ratio and mixed, and then formed into a cutting tool shape (SEEN1203AFTN) by pressing. For the obtained formed body, dewaxing treatment was performed, and firing was carried out at 1400 °C for 1 hour in a vacuum of 0.5 to 100 Pa to fabricate a substrate made of cemented carbide. In addition, tool tip treatment (R honing) was performed on the rake face (first face) side of the fabricated substrate by brushing.

[0039] Next, a coating film (AlTiN film) having a thickness of 1 to 20 μm was formed on the obtained substrate by CVD method to obtain the coated cutting tools shown in Table 1. The film formation conditions are shown in Table 1. The thickness of the coating film was obtained by cross-sectional measurement by SEM. The flow rate was calculated according to V = (S / L) × (T' / P'). V is the flow rate, S is the cross-sectional area of the furnace (m 2) Here, L is the flow rate, T’ is the film-forming temperature (K) / 300K, and P’ is the pressure inside the furnace (kPa) / 101.325 kPa. The cross-sectional area inside the furnace is obtained based on the cross-sectional area of the plane perpendicular to the gas ejection port. When the cross-sectional area inside the furnace varies depending on the position, for example, the maximum cross-sectional area can be used as the cross-sectional area inside the furnace.

[0040]

Table 1

[0041]

[0042] <Evaluation>

[0043] For the obtained coated cutting tools, the first to fourth Al ratios and interrupted cutting tests were carried out. The following shows each measurement method, and the results are shown in Table 2.

[0044] (First to fourth Al ratios)

[0045] Measured by EDS analysis method.

[0046] (Interrupted cutting test: Dry milling center cutting)

[0047] Workpiece material: Chrome molybdenum steel (SCM440)

[0048] Tool shape: SEEN1203AFTN

[0049] Cutting speed: 300 m / minute

[0050] Feed rate: 0.20 mm / rev

[0051] Depth of cut: 2.0 mm

[0052] Evaluation item: Time until chipping (cutting time)

[0053]

Table 2

[0054]

[0055] As shown in Table 2, for samples No. 1 to 4 where the first Al ratio and the second Al ratio are 0.7 or more and the second Al ratio is greater than the first Al ratio, the tool life is long. On the other hand, for samples No. 5 to 7 where the first Al ratio and the second Al ratio are not 0.7 or more, or the second Al ratio is not greater than the first Al ratio, the tool life is short.

[0056] Symbol Explanation

[0057] 1…Coated cutting tool

[0058] 2…Substrate

[0059] 3…Coating film

[0060] 4…Surface

[0061] 5…The first side

[0062] 6…The second side

[0063] 7…Cutting edge

[0064] Positions P1, P2, P3, P4...

Claims

1. A coated cutting tool is a coated cutting tool having a substrate and a coating film located on the substrate, wherein, the coated cutting tool includes: a first surface, a second surface adjacent to the first surface, and a cutting edge located on at least a part of the ridge line portion between the first surface and the second surface, the first surface is a rake face, and the second surface is a flank face, the coating film includes an AlTiN film containing Ti, Al, and N, in the first surface, when the Al / (Al + Ti) at a position 0.1 mm away from the cutting edge is defined as the first Al ratio and the Al / (Al + Ti) at a position 0.2 mm away from the cutting edge is defined as the second Al ratio, the first Al ratio and the second Al ratio are 0.85 or more and 0.95 or less, the second Al ratio is greater than the first Al ratio, in the second surface, when the Al / (Al + Ti) at a position 0.1 mm away from the cutting edge is defined as the third Al ratio and the Al / (Al + Ti) at a position 0.2 mm away from the cutting edge is defined as the fourth Al ratio, the third Al ratio and the fourth Al ratio are 0.85 or more and 0.95 or less, the fourth Al ratio is greater than the third Al ratio, the first Al ratio is greater than the third Al ratio, the second Al ratio is greater than the fourth Al ratio, and the first Al ratio is greater than the fourth Al ratio, R honing is performed on the first surface side of the substrate, and grinding is performed on the region including the cutting edge.

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