JP5610219B2 - Hard coating for cutting tool and hard coating coated cutting tool - Google Patents

Description

  The present invention relates to a hard coating for a cutting tool provided on the surface of a cutting tool and a hard coating coated cutting tool provided with the hard coating, and in particular, an improvement for improving both wear resistance and welding resistance. About.

  Cutting tools such as drills and taps are provided with a hard coating to improve wear resistance. As the hard coating for cutting tools, TiN-based, TiAlN-based, and AlCr-based coatings are widely used, and improvements are made to further improve the performance. For example, it is the hard laminated film described in Patent Document 1.

JP 2006-336032 A

  However, in a cutting tool in which a hard coating is formed by the conventional technique as described above, the welding resistance may be insufficient depending on the type of workpiece and cutting conditions during the cutting process. That is, the tool life may be shortened by welding of the work material or the like, and there is room for improvement. That is, development of a hard coating for a cutting tool and a hard coating coated cutting tool having both excellent wear resistance and welding resistance has been demanded.

  The present invention has been made in the background of the above circumstances, and its object is to provide a hard coating for a cutting tool and a hard coating-coated cutting tool having excellent wear resistance and welding resistance. There is.

In order to achieve such an object, the gist of the first invention is a hard coating for a cutting tool provided on the surface of the cutting tool, which is made of Ti _a Cr _b Al _c Mo _1-abc . A first film layer made of nitride or carbonitride and a second film layer made of Ti _d Cre _e Al _1-de nitride or carbonitride are multilayer films in which two or more layers are alternately laminated; The atomic ratio a related to the first coating layer is in the range of 0.2 to 0.7, b is in the range of 0.01 to 0.2, and c is in the range of 0.01 to 0.2. 1-abc is 0.1 or more, the atomic ratio d according to the second coating layer is in the range of 0.1 to 0.7, and e is 0.01 to 0.2. The film thickness of the first coating layer is in the range of 0.1 μm to 5.0 μm, and the film thickness of the second coating layer is 0.1 μm to 5.0 μm. In the following range, the total film thickness is in the range of 0.2 μm to 10.0 μm.

  In order to achieve the above object, the gist of the second invention is that the hard coating for cutting tool according to the first invention is provided on the surface of the hard coating coated cutting tool. It is.

In this way, the according to the first _{invention, Ti a Cr b Al c Mo} 1-abc a first coating layer made of nitride or _{carbonitride, Ti d Cr e Al 1-} de nitride or a carbonitride The second coating layer made of nitride is a multilayer film in which two or more layers are alternately stacked. The atomic ratio a related to the first coating layer is in the range of 0.2 to 0.7, and b is 0. In the range of 01 or more and 0.2 or less, c is in the range of 0.01 or more and 0.2 or less, 1-abc is 0.1 or more, and the atomic ratio d related to the second coating layer is Within the range of 0.1 to 0.7, e is within the range of 0.01 to 0.2, and the film thickness of the first coating layer is within the range of 0.1 μm to 5.0 μm. The film thickness of the second coating layer is in the range of 0.1 μm to 5.0 μm, and the total film thickness is in the range of 0.2 μm to 10.0 μm. In addition to forming a Mo oxide on the surface of the coating, which provides excellent welding resistance and a high hardness coating, it has a laminated structure of a TiCrAl-based coating and a TiCrAlMo-based coating. It is possible to achieve both welding resistance. That is, it is possible to provide a hard coating for a cutting tool that has both excellent wear resistance and welding resistance.

  Further, according to the second invention, since the hard coating for a cutting tool of the first invention is provided on the surface, Mo oxide is contained on the coating surface by containing Mo in the coating. In addition to being formed and having a high hardness coating as well as having a high hardness, a laminated structure of a TiCrAl-based coating and a TiCrAlMo-based coating can achieve both wear resistance and welding resistance. That is, it is possible to provide a hard coating coated cutting tool having both excellent wear resistance and welding resistance.

It is the front view which looked at the end mill which is one Example of the hard film coating cutting tool of this invention from the direction perpendicular | vertical to an axial center. It is sectional drawing of the surface part of the end mill of FIG. 1 by which the hard film for cutting tools of this invention was coated. It is a schematic block diagram explaining the sputtering device used suitably when forming the hard film for cutting tools of this invention. It is a figure which shows collectively the film structure and film thickness of the test goods used for the test, and the test result of each test goods regarding the test which the present inventors performed in order to verify the effect of this invention. It is a figure which shows collectively the film structure and film thickness of the test article used for the test, and the test result of each test article regarding other tests conducted by the present inventors to verify the effects of the present invention. . It is a graph which shows the result of the test which the present inventors conducted in order to verify the friction characteristic of the hard film for cutting tools of the present invention.

  The hard coating for a cutting tool of the present invention is a surface coating of various cutting tools such as a rotating cutting tool such as an end mill, a drill, a face mill, a total mill, a reamer, a tap, and a non-rotating cutting tool such as a bite. It is preferably applied to. Further, as the material of the tool base material, that is, the member provided with the hard coating, cemented carbide or high-speed tool steel is preferably used, but other materials may be used, and the hard coating for a cutting tool of the present invention may be various materials. Widely applied to cutting tools composed of

  The hard coating for a cutting tool of the present invention is provided so as to cover a part or all of the surface of the cutting tool, and is preferably provided on a blade part involved in cutting in the cutting tool. More preferably, it is provided so as to cover at least the cutting edge or rake face of the blade portion.

  As a method for forming the hard film for a cutting tool of the present invention, a sputtering method is preferably used, but other physical vapor deposition methods (PVD method) such as arc ion plating method, plasma CVD method, thermal CVD method, etc. Chemical vapor deposition (CVD) can also be used.

Cutting tools for hard coating of the present _{invention, Ti a Cr b Al c Mo} 1-abc nitride or a first coating layer made of _{carbonitride, Ti d Cr e Al 1-} de nitride or carbonitride And the second coating layer is a multilayer film in which two or more layers are alternately laminated. The atomic ratio a relating to the first coating layer is in the range of 0.2 or more and 0.7 or less, and b is 0.01 or more. Within the range of 0.2 or less, c is within the range of 0.01 or more and 0.2 or less, 1-abc is 0.1 or more, and the atomic ratio d of the second coating layer is 0.00. In the range of 1 to 0.7, e is in the range of 0.01 to 0.2. However, if the numerical value is out of the range, sufficient wear resistance and welding resistance are obtained. It is conceivable that the tool life is shortened. The atomic ratio a related to the first coating layer is in the range of 0.2 to 0.7, b is in the range of 0.01 to 0.2, and c is in the range of 0.01 to 0.2. 1-a-b-c is 0.1 or more, the atomic ratio d according to the second coating layer is in the range of 0.1 to 0.7, and e is in the range of 0.01 to 0.2. By doing so, a hard coating film having excellent wear resistance and welding resistance can be formed.

  The film thickness of the first coating layer relating to the hard coating for a cutting tool of the present invention is in the range of 0.1 μm to 5.0 μm, and the film thickness of the second coating layer is in the range of 0.1 μm to 5.0 μm. Of these, the total film thickness is in the range of 0.2 μm or more and 10.0 μm or less. However, if the numerical value is out of the range, sufficient wear resistance and welding resistance cannot be obtained, and the tool life is shortened. May be shortened. In particular, if the total thickness of the hard coating is less than 0.2 μm, sufficient wear resistance and welding resistance may not be obtained. In some cases, the tool life may be shortened. The thickness of the first coating layer is in the range of 0.1 μm to 5.0 μm, the thickness of the second coating layer is in the range of 0.1 μm to 5.0 μm, and the total thickness is 0.2 μm or more. By setting the thickness within the range of 10.0 μm or less, it is possible to form a hard coating that has a necessary and sufficient thickness to ensure wear resistance and welding resistance and is less likely to be chipped or peeled off.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front view of an end mill 10 as an embodiment of the hard film-coated cutting tool of the present invention as viewed from a direction perpendicular to the axis. As shown in FIG. 1, the end mill 10 of this embodiment is a rotary cutting tool in which a shank and a blade portion 14 are integrally provided on a tool base material 12 made of, for example, a cemented carbide. The blade portion 14 is provided with an outer peripheral blade 16 and a bottom blade 18 as cutting blades. The outer peripheral blade 16 is attached to a cutting device (not shown) and is driven to rotate around the axis by the cutting device. And the cutting work is performed on the work material by the bottom blade 18.

  FIG. 2 is a cross-sectional view of the surface portion of the end mill 10 coated with the hard film for a cutting tool of the present invention. As shown in FIG. 2, the surface of the end mill 10 is coated with a hard coating 20 that is an example of a hard coating for a cutting tool of the present invention. The hatched portion in FIG. 1 shows a portion of the end mill 10 where the hard coating 20 is provided. As shown in the drawing, the hard coating 20 is preferably applied to the blade portion 14 of the end mill 10. The surface of the corresponding tool base material 12 is provided so as to be covered.

As is clear from FIG. 2, the hard coating 20 of this example is a multilayer film in which two or more first coating layers 22 and second coating layers 24 are alternately stacked. The second coating layer 24 is made of a material that satisfies the chemical composition shown below. That is, the first coating layer _{22, Ti a Cr b Al c Mo} 1-abc a nitride or carbo-nitrides, the atomic ratio (mole ratio) a range of 0.2 to 0.7 B is in the range of 0.01 to 0.2, c is in the range of 0.01 to 0.2, and 1-abc is 0.1 or more. The atomic ratios a to c are appropriately determined within the above numerical range. That is, for example, Ti _0.5 Cr _0.1 Al _0.1 Mo _0.3 N or the like is suitably applied as the first coating layer 22 in the hard coating 20 of the present embodiment. Further, the second coating layer 24 is a Ti _d Cr _e Al _1-de nitride or carbonitride atomic ratio d in the range of 0.1 to 0.7, e is 0.01 It is in the range of 0.2 or more and 0.2 or less. The atomic ratios d and e are appropriately determined within the above numerical range. That is, for example, Ti _0.5 Cr _0.1 Al _0.4 N is suitably applied as the second coating layer 24 in the hard coating 20 of the present embodiment.

 The thickness D1 of each first coating layer 22 in the hard coating 20 is in the range of 0.1 μm to 5.0 μm, and the thickness D2 of the second coating layer 24 is in the range of 0.1 μm to 5.0 μm. Of these, the total film thickness D is in the range of 0.2 μm to 10.0 μm. The number of laminated layers of the first coating layer 22 and the second coating layer 24 is appropriately determined as long as it does not deviate from the above numerical range relating to the total film thickness D of the hard coating 20 and the film thicknesses D1 and D2 of the coating layers 22 and 24. Preferably, it is within the range of 2 layers (the first coating layer 22 and the second coating layer 24 are each one layer) to 60 layers (the first coating layer 22 and the second coating layer 24 are each 30 layers). Is done. Further, the film thicknesses D1 of the plurality of first coating layers 22 in the hard coating 20 may all be the same, or may be different from each other within the above numerical range. Similarly, the film thicknesses D2 of the plurality of second coating layers 24 in the hard coating 20 may all be equal or may be different from each other within the above numerical range.

  Further, the stacking order of the first coating layer 22 and the second coating layer 24 in the hard coating 20 is preferably such that the first coating layer 22 and the second coating from the tool base material 12 side as shown in FIG. The layers 24,..., The second coating layer 24, and the first coating layer 22 are laminated in this order. That is, the base layer of the hard coating 20 (the lowermost layer in contact with the tool base material 12) and the surface layer (the uppermost layer of the hard coating 20) are both the first coating layer 22, but such a configuration is not necessarily required. The present invention is not limited thereto, and even if the second coating layer 24 is a base layer or a surface layer, the effects of the present invention can be obtained.

FIG. 3 is a schematic configuration diagram (schematic diagram) illustrating a sputtering apparatus 30 that is preferably used when forming the hard coating 20 of the present embodiment. In the sputtering process by the sputtering apparatus 30, a negative constant bias voltage (for example, about −50 to −60 V) is applied to the target 38 such as TiAl or Ti constituting the hard coating 20 by the power source 40, and the bias By applying a negative constant bias voltage (for example, about −100 V) to the tool base material 12 by the power source 34, argon ions Ar ⁺ collide with the target 38 to strike out constituent materials such as TiAl and Ti. The voltage applied by the power supply 40 and the bias power supply 34 is controlled by the controller 36. In addition to argon gas, a reactive gas such as nitrogen gas (N ₂ ) or hydrocarbon gas (CH ₄ , C ₂ H ₂ ) is introduced into the chamber 32 at a predetermined flow rate, and the nitrogen atom N or carbon atom C is introduced. Are combined with TiAl, Ti, and the like knocked out from the target 38 to become TiAlN, TiCN, TiN, and the like, and are attached to the surface of the tool base material 12 as a hard coating.

  Subsequently, a test conducted by the present inventors in order to verify the effect of the present invention will be described. FIG. 4 is a diagram showing the configuration (film structure, film thickness, and number of layers) of the test products 1 to 47 used in this test and the test results (cutting distance and determination) of each test product. The inventors of the present invention coat a hard drill having a tool diameter of 6 (mmφ) with a hard film having each configuration shown in FIG. 4 to prepare test samples 1 to 47, and each test product is subjected to a cutting test under the following cutting conditions. Went. Note that, among the test products 1 to 47 shown in FIG. 4, test products 1 to 39 correspond to the present invention product to which the hard coating 20 of this embodiment is applied, and the test products 40 to 47 satisfy the requirements of the present invention. It corresponds to a non-invention product to which a hard coating that is not satisfied is applied. Moreover, among these test products 40 to 47, the test products 40 and 41 correspond to conventional products to which a hard coating made of TiAlN is applied (hard coating coated cutting tool according to the prior art), and the test products 42 to 47 are TiCrAlMoN / Although a hard coating composed of a multilayer film of TiCrAlN is applied, it corresponds to a comparative sample whose atomic ratio deviates from the numerical range of the present invention.

[Cutting conditions]
・ Test product: Carbide drill, tool diameter 6 (mmφ)
・ Work material: SCM440 (JIS standard)
・ Cutting method: Hole machining ・ Cutting speed: 70 (m / min)
・ Feeding speed: 557 (mm / min)
・ Processing depth: 18 (mm)
・ Cutting oil: Water-soluble

The cutting distance (m) indicated by * 1 in FIG. 4 is a cutting distance when the flank wear width is within 0.2 (mm). In addition, the determination result indicated by * 2 is a pass product that satisfies the pass criteria, with the tool life within a flank wear width of 0.2 (mm) continuing for a cutting distance of 80 (m) or longer. Is indicated by ◯, and rejected products not satisfying the acceptance criteria are indicated by ×. As mentioned above, specimens 1 to 39 shown in FIG. 4, a _{Ti a Cr b Al c Mo 1} -abc of the first coating layer 22 made of nitride or _{carbonitride, Ti d Cr e Al 1-} de And the second coating layer 24 made of nitride or carbonitride of the above is a multilayer film in which two or more layers are alternately laminated, and the atomic ratio a related to the first coating layer 22 is 0.2 or more and 0.7 or less. In the range, b is in the range of 0.01 to 0.2, c is in the range of 0.01 to 0.2, 1-abc is 0.1 or more, and the second coating The atomic ratio d related to the layer 24 is in the range of 0.1 to 0.7, e is in the range of 0.01 to 0.2, and the film thickness D1 of the first coating layer 22 is 0. Within the range of 1 μm to 5.0 μm, the film thickness D2 of the second coating layer 24 is within the range of 0.1 μm to 5.0 μm, and the total film thickness D is 0.2 μm to 10.0 μm. The following embodiment are within the scope of those of the hard coating 20 has been applied for. As a result of this test, it can be seen that these test products 1 to 39 all satisfy the above acceptance criteria and are being cut well.

On the other hand, the test product 40 shown in FIG. 4 has a hard film (single layer film) made of Ti _0.52 Al _0.48 N with a film thickness of 10.3 (μm), and the test product 41 is made of Ti _0.48 Al _0.52 N. A hard film (single layer film) having a film thickness of 5.0 (μm) is formed, and each corresponds to a non-invention product to which the hard film of the prior art is applied. As a result of this test, it can be seen that none of these test products 40 and 41 satisfied the above-mentioned acceptance criteria, and good cutting was not performed.

4 has a first coating layer with a thickness of 5.20 (μm) made of Ti _0.63 Cr _0.07 Al _0.14 Mo _0.16 N, and a thickness of 5.10 (μm) made of Ti _0.10 Cr _0.12 Al _0.78 N. The second coating layer of 10 (μm) is a multilayer film having a total film thickness of 10.3 (μm) formed by alternately stacking two layers, and the thickness D1 of the first coating layer is related to the present invention. Deviation from the range of 0.1 μm or more and 5.0 μm or less, the film thickness D2 of the second coating layer deviates from the range of 0.1 μm or more and 5.0 μm or less according to the present invention, and the total film thickness D is It deviates from the range of 0.2 μm or more and 10.0 μm or less according to the present invention. As a result of this test, it can be seen that the test product 42 did not satisfy the acceptance criteria, and good cutting was not performed. From this result, it is verified that the film thickness D1 of the first coating layer should be 5.0 μm or less, the film thickness D2 of the second coating layer should be 5.0 μm or less, and the total film thickness D should be 10.0 μm or less, The significance of the numerical range according to the present invention was confirmed.

Further, the test article 43 shown in FIG. 4 includes a first coating layer having a thickness of 0.08 (μm) made of Ti _0.19 Cr _0.03 Al _0.21 Mo _0.57 N, and a thickness of 0. 6 made of Ti _0.65 Cr _0.22 Al _0.13 N. The second coating layer of 08 (μm) is a multilayer film having a total film thickness of 0.16 (μm) formed by alternately stacking two layers, and the atomic ratio a of Ti related to the first coating layer is While deviating from the range of 0.2 or more and 0.7 or less according to the invention, the atomic ratio c of Al deviates from the range of 0.01 or more and 0.2 or less according to the present invention. Further, the film thickness D1 of the first coating layer deviates from the range of 0.1 μm or more and 5.0 μm or less according to the present invention, and the film thickness D2 of the second coating layer is 0.1 μm or more and 5.0 μm according to the present invention. The total thickness D deviates from the range of 0.2 μm or more and 10.0 μm or less according to the present invention. As a result of this test, it can be seen that the test product 43 did not satisfy the acceptance criteria and did not perform good cutting. From this result, in particular, the atomic ratio a of Ti related to the first coating layer is 0.2 or more, the atomic ratio c of Al is 0.2 or less, the film thickness D1 of the first coating layer is 0.1 μm or more, and the second coating It was verified that the film thickness D2 of the layer should be 0.1 μm or more and the total film thickness D should be 0.2 μm or more, and the significance of the numerical range according to the present invention was confirmed.

Further, the test product 44 shown in FIG. 4 has a first coating layer having a film thickness of 5.20 (μm) made of Ti _0.69 Cr _0.01 Al _0.21 Mo _0.09 N, and a film thickness 0. 5 made of Ti _0.09 Cr _0.21 Al _0.70 N. The second coating layer of 08 (μm) is a multilayer film having a total film thickness of 5.3 (μm) formed by alternately stacking two layers, and the atomic ratio c of Al related to the first coating layer is While deviating from the range of 0.01 or more and 0.2 or less according to the invention, the atomic ratio 1-abbc of Mo is less than 0.1. Further, the atomic ratio d of Ti related to the second coating layer deviates from the range of 0.1 or more and 0.7 or less according to the present invention, and the atomic ratio e of Cr is 0.01 or more and 0.00 according to the present invention. Deviation from within 2 or less. Furthermore, the film thickness D1 of the first coating layer deviates from the range of 0.1 μm or more and 5.0 μm or less according to the present invention, and the film thickness D2 of the second coating layer is 0.1 μm or more and 5.0 μm according to the present invention. Deviations from within the following ranges. As a result of this test, it can be seen that this test product 44 did not satisfy the acceptance criteria and did not perform good cutting. From this result, in particular, the atomic ratio c of Al related to the first coating layer is 0.2 or less, the atomic ratio 1-abc of Mo is 0.1 or more, and the atomic ratio d of Ti related to the second coating layer. Is 0.1 or more, the atomic ratio e of Cr is 0.2 or less, the thickness D1 of the first coating layer is 0.5 μm or less, and the thickness D2 of the second coating layer is 0.1 or more Thus, the significance of the numerical range according to the present invention was confirmed.

Moreover, the test article 45 shown in FIG. 4, a first coating layer having a thickness of 0.08 ([mu] m) made of _{Ti 0.50 Cr 0.05 Al 0.05 Mo 0.40} N, the thickness 5 consisting of Ti _0.55 Cr _0.15 Al _0.30 N. 5 (μm) of the second coating layer is a multilayer film having a total film thickness of 5.58 (μm) formed by alternately stacking two layers, and the thickness D1 of the first coating layer is related to the present invention. While deviating from the range of 0.1 μm to 5.0 μm, the film thickness D2 of the second coating layer deviates from the range of 0.1 μm to 5.0 μm according to the present invention. As a result of this test, it can be seen that the test product 45 did not satisfy the acceptance criteria, and good cutting was not performed. From this result, it was verified that the film thickness D1 of the first coating layer should be 0.1 μm or more and the film thickness D2 of the second coating layer should be 5.0 μm or less, and the significance of the numerical range according to the present invention was confirmed. It was.

Further, the test product 46 shown in FIG. 4 includes a first coating layer having a film thickness of 0.08 (μm) made of Ti _0.35 Cr _0.21 Al _0.21 Mo _0.23 N, and a film thickness 0. 5 made of Ti _0.10 Cr _0.009 Al _0.89 N. The second coating layer of 07 (μm) is a multilayer film having a total film thickness of 3.8 (μm) formed by alternately stacking 50 layers, and the atomic ratio b of Cr related to the first coating layer is While deviating from the range of 0.01 or more and 0.2 or less according to the invention, the atomic ratio c of Al deviates from the range of 0.01 or more and 0.2 or less according to the present invention. Further, the atomic ratio e of Cr in the second coating layer deviates from the range of 0.01 to 0.2 according to the present invention. Furthermore, the film thickness D1 of the first coating layer deviates from the range of 0.1 μm or more and 5.0 μm or less according to the present invention, and the film thickness D2 of the second coating layer is 0.1 μm or more and 5.0 μm according to the present invention. Deviations from within the following ranges. As a result of this test, it can be seen that the test product 46 did not satisfy the acceptance criteria, and good cutting was not performed. From this result, in particular, the atomic ratio b of Cr related to the first coating layer is 0.2 or less, the atomic ratio c of Al is 0.2 or less, the atomic ratio e of Cr related to the second coating layer is 0.01 or more, It was verified that the thickness D1 of the first coating layer should be 0.1 μm or more and the thickness D2 of the second coating layer should be 0.1 μm or more, and the significance of the numerical range according to the present invention was confirmed.

4 has a first coating layer having a thickness of 2.50 (μm) made of Ti _0.59 Cr _0.22 Al _0.10 Mo _0.09 N and a thickness of _3.0.71 Cr _0.15 Al _0.14 N. The second coating layer of 0 (μm) is a multilayer film having a total film thickness of 5.5 (μm) formed by alternately stacking two layers, and the atomic ratio b of Cr related to the first coating layer is While deviating from the range of 0.01 or more and 0.2 or less according to the invention, the atomic ratio 1-abbc of Mo is less than 0.1. Further, the atomic ratio d of Ti related to the second coating layer deviates from the range of 0.1 or more and 0.7 or less according to the present invention. It can be seen that the test product 47 did not satisfy the acceptance criteria and was not cut well. From this result, in particular, the atomic ratio b of Cr related to the first coating layer is 0.2 or less, the atomic ratio 1-abc of Mo is 0.1 or more, and the atomic ratio d of Ti related to the second coating layer. Was verified to be 0.7 or less, and the significance of the numerical range according to the present invention was confirmed.

As apparent from the above description, from the result of this test shown in FIG. 4, the first coating layer made of a nitride or carbonitride of Ti _a Cr _b Al _c Mo _1-abc , and Ti _d Cr _e Al ₁ and a second coating layer made of nitride or carbonitride of _-de is a multilayer film in which two or more layers are alternately laminated, and the atomic ratio a related to the first coating layer is 0.2 or more and 0.7 or less In the range, b is in the range of 0.01 to 0.2, c is in the range of 0.01 to 0.2, 1-abc is 0.1 or more, and the second coating The atomic ratio d relating to the layer is in the range of 0.1 to 0.7, e is in the range of 0.01 to 0.2, and the film thickness of the first coating layer is 0.1 μm or more. Within the range of 5.0 μm or less, the film thickness of the second coating layer is within the range of 0.1 μm to 5.0 μm, and the total film thickness is within the range of 0.2 μm to 10.0 μm. While good cutting performance can be obtained in the cutting tool to which the hard coating 20 of the present embodiment is applied, good cutting performance cannot be obtained in the cutting tool to which the hard coating having a configuration deviating from each numerical range is applied. I understood. That is, the significance of the numerical range according to the present invention is confirmed, and only when the numerical range is satisfied, can a hard coating or a hard coating coated cutting tool exhibit cutting performance superior to that of the prior art be realized. Verified.

  FIG. 5 shows the configurations of Example Samples 1 to 4 and conventional products used in the test (the film structure, the film thickness, and the other test) conducted by the inventors in order to verify the effect of the present invention. It is a figure which shows collectively the number of laminations) and the test result of each test product. The inventors prepared a test sample 1-5, that is, Example Samples 1 to 4 and a conventional product by coating a hard drill having a tool diameter of 6 (mmφ) with a hard film having each configuration shown in FIG. The test product was subjected to a cutting test under the following cutting conditions. In addition, among the test products shown in FIG. 5, Example Samples 1 to 4 correspond to the products of the present invention to which the hard coating 20 of the present example is applied, and the conventional products do not satisfy the requirements of the present invention. It corresponds to the applied non-invention product. Further, this conventional product corresponds to a hard film coated cutting tool according to the prior art to which a hard film made of TiAlN is applied.

[Cutting conditions]
・ Test product: Carbide drill, tool diameter 6 (mmφ)
・ Work material: SCM440 (JIS standard)
・ Cutting method: Hole machining ・ Cutting speed: 70 (m / min)
・ Feeding speed: 557 (mm / min)
・ Processing depth: 18 (mm)
・ Cutting oil: Water-soluble

The cutting distance (m) shown in FIG. 5 is a cutting distance when the flank wear width is within 0.2 (mm). In addition, the determination result is that a tool life within a flank wear width of 0.2 (mm) continues for a cutting distance of 80 (m) or more, and a pass product that satisfies the pass criteria is ○ Rejected products that do not satisfy the acceptance criteria are indicated by crosses. As described above, the example samples 1 to 4 shown in FIG. 5 include the first coating layer 22 made of Ti _a Cr _b Al _c Mo _1-abc nitride or carbonitride, and the Ti _d Cr _e Al _1- The second coating layer 24 made of _de nitride or carbonitride is a multilayer film in which two or more layers are alternately stacked, and the atomic ratio a related to the first coating layer 22 is 0.2 or more and 0.7 or less. , B is in the range of 0.01 to 0.2, c is in the range of 0.01 to 0.2, 1-abc is 0.1 or more, and the second The atomic ratio d related to the coating layer 24 is in the range of 0.1 to 0.7, e is in the range of 0.01 to 0.2, and the film thickness D1 of the first coating layer 22 is Within the range of 0.1 μm to 5.0 μm, the film thickness D2 of the second coating layer 24 is within the range of 0.1 μm to 5.0 μm, and the total film thickness D is 0.2 μm to 10.0. m is within the range in which the hard coating 20 of the present embodiment is applied. As a result of this test, it can be seen that these Example Samples 1 to 4 all satisfy the above acceptance criteria and are being cut well. On the other hand, the conventional product shown in FIG. 5 is formed with a hard film (single layer film) having a film thickness of 7.8 (μm) made of Ti _0.5 Al _0.5 N, and the conventional hard film was applied. It corresponds to a non-invention product. As a result of this test, it can be seen that this conventional product did not satisfy the above acceptance criteria, and good cutting was not performed.

  5 are applied with the hard coating 20 of this embodiment in which the base layer, that is, the base layer in contact with the tool base material 12 and the surface layer, that is, the surface layer, are variously replaced with TiCrAlMoN or TiCrAlN. It is a thing. That is, Example Sample 1 has a base layer of TiCrAlMoN, that is, a first coating layer 22, and a surface layer of TiCrAlN, that is, a second coating layer 24. Example Sample 2 has both a base layer and a surface layer of TiCrAlMoN, that is, a first coating layer. In Example Sample 3, the base layer and the surface layer are both TiCrAlN, that is, the second coating layer 24. In Example Sample 4, the base layer is TiCrAlN, that is, the second coating layer 24, and the surface layer is TiCrAlMoN, that is, The first coating layer 22 is formed. As is apparent from the results of FIG. 5, the cutting distance when the flank wear width is within 0.2 (mm) in the example sample 2 in which the base layer and the surface layer are both TiCrAlMoN, that is, the first coating layer 22, is 96. It can be seen that the wear resistance is the best at .5 (m). On the other hand, in Example Samples 1, 3, and 4 in which at least one of the base layer and the surface layer is TiCrAlN, that is, the second coating layer 24, the flank wear width is within 0.2 (mm) even if it does not reach Example Sample 2. In some cases, the cutting distance is 80 (m) or more, indicating good wear resistance. From this result, in the hard coating 20, it is desirable that both the base layer and the surface layer are the first coating layer 22. However, even in a configuration in which at least one of the base layer and the surface layer is the second coating layer 24, the present invention is also suitable for the present invention. It was verified that the effect was achieved.

FIG. 6 is a graph showing the results of tests conducted by the present inventors in order to verify the friction characteristics of the hard coating 20 of this example. The present inventors made an example sample in which the well-known super indenter was coated with the hard film 20 of the present example and a comparative example sample in which the conventional hard film was coated, and a test for comparing the friction characteristics thereof. Went. That is, an example sample in which a multilayer film having a thickness of 3.0 μm made of Ti _0.5 Cr _0.1 Al _0.1 Mo _0.3 N / Ti _0.5 Cr _0.1 Al _0.4 N was applied as the hard film 20 of the present example, and a conventional hard film as A comparative sample having a single layer film of Ti _0.5 Al _0.5 N having a thickness of 3.0 μm was prepared, and a friction test was performed under the following conditions.

[Test conditions]
・ Test article: Carbide indenter This is an indenter specified in JIS R1613 "Friction wear test method of fine ceramics by ball-on-disk method", φ5mm (R shape at the tip)
・ Friction material: S45C (JIS standard)
・ Weight: 50 (g)
・ Friction speed: 100 (mm / s)
・ Friction time: 600 (s)
・ Temperature: 22 (℃)
・ Humidity: 35 (%)

In FIG. 6, as a result of the friction test, the result of the example sample in which a multilayer film having a thickness of 3.0 μm made of Ti _0.5 Cr _0.1 Al _0.1 Mo _0.3 N / Ti _0.5 Cr _0.1 Al _0.4 N is applied is shown by a solid line. The results of the comparative example samples to which a single layer film made of Ti _0.5 Al _0.5 N and having a thickness of 3.0 μm are applied are shown by broken lines. As shown in FIG. 6, the sample with the hard coating 20 of the present example has a coefficient of friction (μ) of approximately 20 over a test time of 600 (s) compared to the sample with the conventional hard coating. As a result, a value as low as about 30% was exhibited, and excellent friction characteristics (lubricity) were exhibited. This result shows that the sample to which the hard coating 20 of the present embodiment is applied is less likely to be worn than the sample to which the conventional hard coating is applied, and the work material (friction material) is welded. This proves that it is difficult to occur. Thus, the reason why the sample to which the hard coating 20 of this example is applied exhibits superior wear resistance and welding resistance compared to the sample to which the conventional hard coating is applied is that Mo is contained in the coating. This is presumably because Mo oxide is formed on the coating surface. From the above results, it was verified that the cutting tool to which the hard coating 20 of the present example was applied can achieve superior wear resistance and welding resistance as compared with the conventional technique.

Thus, according to the present embodiment, the hard coating 20 provided on the surface of the cutting tool including the end mill 10 is provided, which is a Ti _a Cr _b Al _c Mo _1-abc nitride or charcoal. a first coating layer 22 made of nitride, a Ti _d Cr _e Al _1-de of the second coating layer 24 made of nitride or carbonitride, a multilayer film formed by laminating alternately two or more layers, the first The atomic ratio a relating to one coating layer 22 is in the range of 0.2 to 0.7, b is in the range of 0.01 to 0.2, c is in the range of 0.01 to 0.2, 1-abc is 0.1 or more, the atomic ratio d according to the second coating layer 24 is in the range of 0.1 to 0.7, and e is 0.01 to 0.2. The film thickness D1 of the first coating layer 22 is in the range of 0.1 μm or more and 5.0 μm or less, and the film thickness of the second coating layer 24 is within the range. 2 is in the range of 0.1 μm or more and 5.0 μm or less, and the total film thickness D is in the range of 0.2 μm or more and 10.0 μm or less. Therefore, by containing Mo in the coating, Mo oxide is formed on the coating surface. In addition to being excellent in welding resistance and obtaining a high-hardness coating, a laminated structure of a TiCrAl-based coating and a TiCrAlMo-based coating can achieve both wear resistance and welding resistance. That is, it is possible to provide the hard coating 20 having both excellent wear resistance and welding resistance.

  Moreover, according to the present embodiment, since the hard coating 20 is an end mill 10 as a cutting tool provided on the surface, Mo oxide is formed on the coating surface by containing Mo in the coating. In addition to being able to obtain a coating film having excellent welding resistance and a high hardness, it is possible to achieve both wear resistance and welding resistance by employing a laminated structure of a TiCrAl-based film and a TiCrAlMo-based film. That is, the end mill 10 having both excellent wear resistance and welding resistance can be provided.

  The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention. Is.

10: End mill (cutting tool)
20: Hard coating for cutting tool 22: First coating layer 24: Second coating layer d: Total film thickness d1: Film thickness of first coating layer d2: Film thickness of second coating layer

Claims (2)

A hard coating for a cutting tool provided on the surface of a cutting tool,
And _{Ti a Cr b Al c Mo 1} -abc nitride or first coating layer made of carbonitride, and the Ti _d Cr _e Al _1-de nitride or the second coating layer made of carbonitride, alternating A multilayer film in which two or more layers are laminated,
The atomic ratio a related to the first coating layer is in the range of 0.2 to 0.7, b is in the range of 0.01 to 0.2, and c is in the range of 0.01 to 0.2. , 1-abc is 0.1 or more,
The atomic ratio d according to the second coating layer is in the range of 0.1 to 0.7, e is in the range of 0.01 to 0.2,
In addition, the thickness of the first coating layer is in the range of 0.1 μm to 5.0 μm, the thickness of the second coating layer is in the range of 0.1 μm to 5.0 μm, and the total thickness is 0.00. Hard coating for cutting tools, characterized in that it is in the range of 2 μm or more and 10.0 μm or less.   A hard coating-coated cutting tool provided with the hard coating for a cutting tool according to claim 1 coated on a surface thereof.

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