Coated and cutting tools

Abstract

A coated tool (1) according to the present disclosure comprises a base material (10) and a coating film (20). The base material (10) is composed of a cemented carbide or a cermet. The coating film (20) is positioned on top of the base material (10). In addition, the coating film (20) comprises a hard layer (21) and a metal layer (22) that is composed of a metal other than elemental Ti, Zr, V, Cr, Ta, Nb, Hf and Al, while being positioned between the base material (10) and the hard layer (21).

Description

[Technical Field]

[0001] The present disclosure relates to coated tools and cutting tools. [Background technology]

[0002] As a tool used in cutting processes such as turning and milling, a coated tool is known in which the surface of a substrate made of cemented carbide, cermet, ceramics, or the like is coated with a coating film to improve wear resistance and the like (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5160231 Summary of the Invention

[0004] A coated tool according to one embodiment of the present disclosure includes a substrate and a coating film. The substrate is made of cemented carbide or cermet. The coating film is located on the substrate. The coating film also includes a hard layer and a metal layer other than a simple element selected from Ti, Zr, V, Cr, Ta, Nb, Hf, and Al, located between the substrate and the hard layer. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a perspective view showing an example of a coated tool according to an embodiment. [Figure 2] FIG. 2 is a side cross-sectional view showing an example of a coated tool according to an embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing an example of a coating film according to an embodiment. [Figure 4] FIG. 4 is a schematic enlarged view of part H shown in FIG. [Figure 5] FIG. 5 is a front view showing an example of a cutting tool according to an embodiment. [Figure 6] FIG. 6 is a table showing the configuration of each sample. [Figure 7]FIG. 7 is a table showing the results of the indentation hardness test for each sample. DETAILED DESCRIPTION OF THE INVENTION

[0006] Hereinafter, modes for carrying out a coated tool and a cutting tool according to the present disclosure (hereinafter referred to as "embodiments") will be described in detail with reference to the drawings. Note that the coated tool and the cutting tool according to the present disclosure are not limited to these embodiments. Furthermore, the respective embodiments can be appropriately combined within the scope of not causing any contradiction in the processing content. Furthermore, the same components in the following embodiments will be given the same reference numerals, and redundant explanations will be omitted.

[0007] Furthermore, in the following embodiments, expressions such as "constant," "orthogonal," "perpendicular," or "parallel" may be used, but these expressions do not necessarily mean "constant," "orthogonal," "perpendicular," or "parallel" in the strict sense. In other words, the above expressions allow for deviations due to, for example, manufacturing precision, installation precision, etc.

[0008] The above-mentioned prior art techniques have room for further improvement in terms of improving the adhesion between the coating film and the substrate.

[0009] The present disclosure has been made in view of the above, and provides a coated tool and a cutting tool that can improve the adhesion between a coating film and a substrate.

[0010] <Coated tools> Fig. 1 is a perspective view showing an example of a coated tool according to an embodiment. Fig. 2 is a side cross-sectional view showing an example of a coated tool 1 according to an embodiment. As shown in Fig. 1, the coated tool 1 according to an embodiment has a tip body 2.

[0011] (Chip body 2) The chip body 2 has, for example, a hexahedral shape in which the upper and lower surfaces (surfaces intersecting with the Z axis shown in FIG. 1) are parallelogram-shaped.

[0012] One corner of the insert body 2 functions as a cutting edge portion. The cutting edge portion has a first surface (for example, an upper surface) and a second surface (for example, a side surface) connected to the first surface. In the embodiment, the first surface functions as a "rake surface" that scoops up chips generated by cutting, and the second surface functions as a "flank surface." A cutting edge is located on at least a portion of the ridge where the first surface and the second surface intersect, and the coated tool 1 cuts the workpiece by applying this cutting edge to the workpiece.

[0013] A through-hole 5 that passes through the tip body 2 from top to bottom is located in the center of the tip body 2. A screw 75 is inserted into the through-hole 5 to attach the coated tool 1 to a holder 70 (described later) (see FIG. 5).

[0014] As shown in FIG. 2, the chip body 2 has a base 10 and a coating film 20.

[0015] (Base 10) The substrate 10 is formed of, for example, a cemented carbide. The cemented carbide contains W (tungsten), specifically WC (tungsten carbide). The cemented carbide may also contain Ni (nickel) or Co (cobalt). The substrate 10 may also be formed of a cermet. The cermet contains, for example, Ti (titanium), specifically TiC (titanium carbide) or TiN (titanium nitride). The cermet may also contain Ni or Co. The coating film 20 will be described later.

[0016] (Coating film 20) The coating film 20 is applied to the substrate 10 for the purpose of improving the abrasion resistance, heat resistance, etc. of the substrate 10. In the example of FIG. 2, the coating film 20 covers the entire substrate 10. The coating film 20 needs to be located at least on the substrate 10. When the coating film 20 is located on the first surface (here, the top surface) of the substrate 10, the abrasion resistance and heat resistance of the first surface are high. When the coating film 20 is located on the second surface (here, the side surface) of the substrate 10, the abrasion resistance and heat resistance of the second surface are high.

[0017] Here, a specific configuration of the coating film 20 will be described with reference to Fig. 3. Fig. 3 is a cross-sectional view showing an example of the coating film 20 according to the embodiment.

[0018] As shown in FIG. 3, the coating film 20 has a hard layer 21. The hard layer 21 is a layer that has superior wear resistance compared to a metal layer 22 described later. The hard layer 21 has one or more metal nitride layers. The hard layer 21 may be a single layer. Alternatively, as shown in FIG. 3, the hard layer 21 may have a plurality of metal nitride layers stacked one on top of the other. Alternatively, the hard layer 21 may have a stacked portion 23 in which a plurality of metal nitride layers are stacked, and a third metal nitride layer 24 located on the stacked portion 23. The configuration of the hard layer 21 will be described later.

[0019] (metal layer 22) The coating film 20 also has a metal layer 22. The metal layer 22 is located between the substrate 10 and the hard layer 21. Specifically, one surface (here, the lower surface) of the metal layer 22 contacts the upper surface of the substrate 10, and the other surface (here, the upper surface) of the metal layer 22 contacts the lower surface of the hard layer 21.

[0020] The metal layer 22 has higher adhesion to the substrate 10 than the hard layer 21. Examples of metal elements having such properties include Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Y, and Ti. The metal layer 22 contains at least one of the above metal elements.

[0021] Note that elemental Ti, elemental Zr, elemental V, elemental Cr, and elemental Al are not used for the metal layer 22. These elements all have low melting points and low oxidation resistance, making them unsuitable for use in cutting tools. Also, elemental Hf, elemental Nb, elemental Ta, and elemental Mo have low adhesion to the substrate 10. However, this does not apply to alloys containing Ti, Zr, V, Cr, Ta, Nb, Hf, and Al.

[0022] The metal layer 22 may be an Al-Cr alloy layer containing an Al-Cr alloy. Such a metal layer 22 has particularly high adhesion to the substrate 10, and is therefore highly effective in improving adhesion between the substrate 10 and the coating film 20.

[0023] When the metal layer 22 is an Al-Cr alloy layer, the Al content in the metal layer 22 may be greater than the Cr content in the metal layer 22. For example, the composition ratio (atomic %) of Al to Cr in the metal layer 22 may be 70:30. With such a composition ratio, the adhesion between the substrate 10 and the metal layer 22 is higher.

[0024] The metal layer 22 may contain components other than the above metal elements (Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Si, Y, and Ti). However, from the viewpoint of adhesion to the substrate 10, the metal layer 22 may contain at least 95 atomic % or more of the above metal elements in total. More preferably, the metal layer 22 may contain at least 98 atomic % or more of the above metal elements in total. For example, when the metal layer 22 is an Al-Cr alloy layer, the metal layer 22 may contain at least 95 atomic % or more of Al and Cr in total. Furthermore, the metal layer 22 may contain at least 98 atomic % or more of Al and Cr in total. The proportion of the metal components in the metal layer 22 can be determined, for example, by analysis using EDS (energy dispersive X-ray spectrometry).

[0025] The substrate 10 may have a binder phase such as Co. A binder phase made of a metal has a high affinity with the metal layer 22. Therefore, by providing the substrate 10 with a binder phase, the adhesion between the substrate 10 and the metal layer 22 can be further improved.

[0026] In this way, in the coated tool 1 according to the embodiment, the metal layer 22, which has higher wettability with the substrate 10 than the hard layer 21, is provided between the substrate 10 and the hard layer 21, thereby improving the adhesion between the substrate 10 and the coating film 20. Furthermore, since the metal layer 22 also has high adhesion with the hard layer 21, peeling of the hard layer 21 from the metal layer 22 is unlikely to occur.

[0027] The coated tool 1 may also have a compound containing the metal element contained in the substrate 10 and the metal element contained in the metal layer 22 at the interface F between the substrate 10 and the metal layer 22.

[0028] For example, the substrate 10 may be a cemented carbide, and the metal layer 22 may be a TiSi layer containing Ti and Si. In this case, the coated tool 1 may have TiW (titanium tungsten) at the interface F between the substrate 10 and the metal layer 22.

[0029] In this way, the presence of a compound containing the metal element contained in the substrate 10 and the metal layer 22 at the interface F between the substrate 10 and the metal layer 22 can increase the adhesion between the substrate 10 and the metal layer 22. Therefore, the coated tool 1 can improve the adhesion between the coating film 20 and the substrate (here, the substrate 10).

[0030] The metal layer 22 is formed by arc ion plating (AIP). The AIP method is a method of forming a metal nitride film by evaporating a target metal using arc discharge in a vacuum atmosphere and combining it with N2 gas. At this time, a bias voltage of 400 V or more may be applied to the substrate 10 to be coated. The hard layer 21, which will be described later, may also be formed by AIP.

[0031] (hard layer 21) Next, the configuration of the hard layer 21 will be described with reference to Fig. 4. Fig. 4 is a schematic enlarged view of part H shown in Fig. 3.

[0032] As shown in FIG. 4, the hard layer 21 has a stacked portion 23 located on the metal layer 22 and a third metal nitride layer 24 located on the stacked portion 23.

[0033] The laminated portion 23 has a plurality of first metal nitride layers 23a and a plurality of second metal nitride layers 23b. The laminated portion 23 has a configuration in which the first metal nitride layers 23a and the second metal nitride layers 23b are alternately laminated.

[0034] The thickness of each of the first metal nitride layer 23a and the second metal nitride layer 23b may be 50 nm or less. By forming the first metal nitride layer 23a and the second metal nitride layer 23b thin in this manner, the residual stress of the first metal nitride layer 23a and the second metal nitride layer 23b is small. As a result, for example, peeling or cracking of the first metal nitride layer 23a and the second metal nitride layer 23b is less likely to occur, and therefore the durability of the coating film 20 is high.

[0035] The first metal nitride layer 23a is a layer in contact with the metal layer 22, and the second metal nitride layer 23b is formed on the first metal nitride layer 23a.

[0036] The first metal nitride layer 23a and the second metal nitride layer 23b may contain the metal contained in the metal layer 22.

[0037] For example, suppose that metal layer 22 contains two types of metals (here, referred to as a "first metal" and a "second metal"). In this case, first metal nitride layer 23a contains nitrides of the first metal and a third metal. The third metal is a metal not contained in metal layer 22. Furthermore, second metal nitride layer 23b contains nitrides of the first metal and the second metal.

[0038] For example, in an embodiment, metal layer 22 may contain Al and Cr. In this case, first metal nitride layer 23a may contain Al. Specifically, first metal nitride layer 23a may be an AlTiN layer containing AlTiN, which is a nitride of Al and Ti. Furthermore, second metal nitride layer 23b may be an AlCrN layer containing AlCrN, which is a nitride of Al and Cr.

[0039] In this way, by positioning the first metal nitride layer 23a containing the metal contained in the metal layer 22 on the metal layer 22, the adhesion between the metal layer 22 and the hard layer 21 is high. This makes it difficult for the hard layer 21 to peel off from the metal layer 22, and therefore the durability of the coating film 20 is high.

[0040] The first metal nitride layer 23a, i.e., the AlTiN layer, has excellent adhesion to the metal layer 22, as described above, and also has excellent wear resistance, for example. The second metal nitride layer 23b, i.e., the AlCrN layer, has excellent heat resistance and oxidation resistance, for example. By including the first metal nitride layer 23a and the second metal nitride layer 23b, which have different compositions, the coating film 20 can control the properties of the hard layer 21, such as wear resistance and heat resistance. This can extend the tool life of the coated tool 1. For example, the hard layer 21 according to the embodiment can improve mechanical properties, such as adhesion to the metal layer 22 and wear resistance, while maintaining the excellent heat resistance of AlCrN.

[0041] The third metal nitride layer 24 may be located on the stacked portion 23. Specifically, the third metal nitride layer 24 is in contact with the second metal nitride layer 23b of the stacked portion 23. The third metal nitride layer 24 is, for example, a metal nitride layer containing Ti and Al (AlTiN layer) similar to the first metal nitride layer 23a.

[0042] The thickness of third metal nitride layer 24 may be thicker than the thicknesses of first metal nitride layer 23a and second metal nitride layer 23b. Specifically, when the thicknesses of first metal nitride layer 23a and second metal nitride layer 23b are 50 nm or less as described above, the thickness of third metal nitride layer 24 may be 1 μm or more. For example, the thickness of third metal nitride layer 24 may be 1.2 μm.

[0043] As a result, for example, when the friction coefficient of the third metal nitride layer 24 is low, the adhesion resistance of the coated tool 1 can be improved. Also, for example, when the hardness of the third metal nitride layer 24 is high, the wear resistance of the coated tool 1 can be improved. Also, for example, when the oxidation onset temperature of the third metal nitride layer 24 is high, the oxidation resistance of the coated tool 1 can be improved.

[0044] Furthermore, the thickness of third metal nitride layer 24 may be thicker than the thickness of laminated portion 23. Specifically, in the embodiment, when the thickness of laminated portion 23 is 0.5 μm or less, the thickness of third metal nitride layer 24 may be 1 μm or more. For example, when the thickness of laminated portion 23 is 0.3 μm, the thickness of third metal nitride layer 24 may be 1.2 μm. In this way, by making third metal nitride layer 24 thicker than laminated portion 23, the effects of improving the above-mentioned welding resistance, wear resistance, etc. are further enhanced.

[0045] The thickness of metal layer 22 may be, for example, not less than 0.1 μm and less than 0.6 μm. That is, metal layer 22 may be thicker than each of first metal nitride layer 23 a and second metal nitride layer 23 b, and thinner than stacked portion 23.

[0046] When the metal layer 22 is a TiSi layer, the first metal nitride layer 23a may be a nitride layer containing Al, Cr, and Si (AlCrSiN layer), and the second metal nitride layer 23b may be a nitride layer containing Ti and Si (TiSiN layer).

[0047] When the first metal nitride layer 23a is an AlCrSiN layer, the Cr composition ratio in the first metal nitride layer 23a is preferably higher than the Al composition ratio in the first metal nitride layer 23a. That is, the first metal nitride layer 23a is preferably Cr-rich. For example, the Al:Cr composition ratio (atomic %) in the AlCrSiN layer is preferably 40:50. By using such a composition ratio, the peeling resistance of the coating film 20 can be improved compared to when the coating film is Al-rich.

[0048] <Cutting tools> Next, the configuration of a cutting tool including the above-described coated tool 1 will be described with reference to Fig. 5. Fig. 5 is a front view showing an example of a cutting tool according to an embodiment.

[0049] As shown in FIG. 5, a cutting tool 100 according to the embodiment includes a coated tool 1 and a holder 70 for fixing the coated tool 1.

[0050] The holder 70 is a rod-shaped member extending from a first end (the upper end in FIG. 5) to a second end (the lower end in FIG. 5). The holder 70 is made of, for example, steel or cast iron. Of these materials, it is particularly preferable to use steel, which has high toughness.

[0051] The holder 70 has a pocket 73 at the end on the first end side. The pocket 73 is a portion where the coated tool 1 is attached, and has a seating surface that intersects with the rotation direction of the workpiece and a constraint side surface that is inclined relative to the seating surface. The seating surface is provided with a screw hole into which a screw 75, which will be described later, is threaded.

[0052] The coated tool 1 is positioned in a pocket 73 of the holder 70 and attached to the holder 70 by a screw 75. That is, the screw 75 is inserted into the through hole 5 of the coated tool 1, and the tip of the screw 75 is inserted into a threaded hole formed in the seating surface of the pocket 73 to screw the threaded portions together. In this way, the coated tool 1 is attached to the holder 70 so that the cutting edge portion protrudes outward from the holder 70.

[0053] In the embodiment, a cutting tool used for so-called turning is exemplified. Examples of turning include inner diameter machining, outer diameter machining, and grooving. The cutting tool is not limited to that used for turning. For example, the coated tool 1 may be used as a cutting tool used for milling.

[0054] For example, cutting a workpiece includes (1) a step of rotating the workpiece, (2) a step of bringing the cutting edge of the coated tool 1 into contact with the rotating workpiece to cut the workpiece, and (3) a step of separating the coated tool 1 from the workpiece. Typical examples of the material of the workpiece include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0055] (Example: Scratch test and peel test) The inventors of the present application conducted scratch tests and peel tests on samples in which a coating film was formed on a cemented carbide alloy and a cermet. Figure 6 is a table showing the structure of each sample. Figure 7 is a table showing the results of an indentation hardness test on each sample.

[0056] A metal layer having the composition shown in the table of Fig. 6 was provided on the surface of a tool-shaped cemented carbide. Furthermore, a hard layer shown in the table of Fig. 6 was provided on the metal layer (carbide with metal layer). Also, as a comparative example, a hard layer shown in the table of Fig. 6 was provided directly on the cemented carbide (carbide without metal layer).

[0057] A metal layer having the composition shown in the table of Fig. 6 was provided on the surface of the tool-shaped cermet. A hard layer shown in the table of Fig. 6 was then provided on the metal layer (cermet with metal layer). A comparative example was also prepared by providing a hard layer shown in the table of Fig. 6 directly on the cermet (cermet without metal layer).

[0058] These samples were subjected to scratch tests and peel tests. The scratch tests were evaluated based on the magnitude of the peel load, with the larger the peel load, the more difficult it was to peel. Also, the longer the peel time, the more difficult it was to peel.

[0059] The scratch test was carried out using a diamond indenter with a tip shape having a radius of curvature (R) of 200 μm at a speed of 10 mm / min and a loading rate of 100 N per minute.

[0060] The peeling test was performed on hardened SCM415 workpiece using a sample with a tool shape of CNGA120408S01225 under the following processing conditions: cutting speed: 150 m / min, feed rate: 0.1 mm / revolution, depth of cut: 0.2 mm, and the time until the hard layer peeled off was evaluated.

[0061] When comparing cemented carbide without a metal layer with cemented carbide with a metal layer, the cemented carbide with a metal layer had a larger peel load and a significantly longer peel time than the cemented carbide without a metal layer. Furthermore, when comparing cermet without a metal layer with cermet with a metal layer, the cermet with a metal layer had a larger peel load and a significantly longer peel time than the cermet without a metal layer. Thus, the cemented carbide with a metal layer and the cermet with a metal layer are less likely to experience peeling of the coating film than the cemented carbide without a metal layer and the cermet without a metal layer, i.e., the coating film has high durability.

[0062] The indentation hardness test shown in FIG. 7 was carried out using a microindentation hardness tester "ENT-1100b / a" (manufactured by Elionix Co., Ltd.).

[0063] Prior to measuring the hardness, the thickness of the coating film was measured on a cross section of the substrate perpendicular to the surface of the substrate. The thickness of the coating film was 2.7 μm when the metal layer was present. The thickness of the coating film without the metal layer was 2.5 μm. The indenter was pressed from the surface of the coating film by 20% of the thickness of the coating film. The indentation of the indenter into the surface of the coating film was increased in approximately 0.02 μm increments. This indentation depth can be increased by increasing the indentation load. In other words, increasing the indentation depth by 0.02 μm is equivalent to increasing the indentation load by approximately 5 mN increments.

[0064] In this test, the hardness can be measured from the surface of the coating film to the vicinity of the surface of the substrate by pressing the indenter to a depth of 20% of the thickness of the coating film. In this disclosure, the hardness of the coating film refers to the hardness obtained by pressing the indenter from the surface of the coating film to a depth of 20% of the coating film while changing the indentation load, as described above. In the indentation hardness test, the deeper the indentation depth, the deeper the hardness can be measured from the surface of the coating film.

[0065] <Modification> In the above-described embodiment, an example was shown in which the shapes of the upper and lower surfaces of the coated tool 1 were parallelograms, but the shapes of the upper and lower surfaces of the coated tool 1 may be rhombic, square, etc. Furthermore, the shapes of the upper and lower surfaces of the coated tool 1 may be triangular, pentagonal, hexagonal, etc.

[0066] The shape of the coated tool 1 may be either a positive type or a negative type. The positive type is a type in which the side surfaces are inclined with respect to a central axis passing through the centers of the upper and lower surfaces of the coated tool 1, and the negative type is a type in which the side surfaces are parallel to the central axis.

[0067] In the above-described embodiment, the coated tool 1 is described as being used for cutting work, but the coated tool according to the present application can also be applied to tools other than cutting tools, such as excavation tools and blades.

[0068] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0069] 1 Coated tools 2 Chip body 5 through holes 10 Base 20 Coating membrane 21 Hard layer 22 Metal layer 23 Lamination section 23a First metal nitride layer 23b Second metal nitride layer 24 Third metal nitride layer 70 Holder 73 Pocket 75 screws 100 cutting tools

Claims

1. a substrate made of a cemented carbide containing tungsten carbide; a coating film disposed on the substrate; and and The coating film is a hard layer; a metal layer which is a TiSi layer located between the substrate and the hard layer; Including, The hard layer is a first metal nitride layer that is an AlCrSiN layer; a second metal nitride layer which is a TiSiN layer; A coated tool having the following structure.

2. 2. The coated tool according to claim 1, further comprising a compound containing a metal element contained in the substrate and a metal element contained in the metal layer at the interface between the substrate and the metal layer.

3. The coated tool according to claim 1 or 2, wherein the substrate comprises a binder phase.

4. 4. The coated tool according to claim 1, wherein the first metal nitride layer and the second metal nitride layer each have a thickness of 50 nm or less.

5. The hard layer is a stacked layer including a plurality of the first metal nitride layers and a plurality of the second metal nitride layers, in which the first metal nitride layers and the second metal nitride layers are alternately stacked; a third metal nitride layer located at a position farther from the substrate than the stacked portion; and The thickness of the third metal nitride layer is 5. The coated tool according to claim 1, wherein the thickness of the first metal nitride layer is greater than that of the second metal nitride layer.

6. The thickness of the third metal nitride layer is The coated tool according to claim 5 , wherein the thickness is greater than the thickness of the laminate.

7. a rod-shaped holder having a pocket at an end; The coated tool according to any one of claims 1 to 6, which is located in the pocket. A cutting tool having

Images