JP5610218B2 - 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 single layer film made of nitride or carbonitride, wherein the atomic ratio a is in the range of 0.2 to 0.7, b is in the range of 0.01 to 0.2, and c is 0.01 or more. In the range of 0.2 or less, 1-abc is 0.1 or more, and the total film thickness is in the range of 0.2 μm or more and 10.0 μm or less. .

  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.

Thus, according to the first aspect of the present invention, the single layer film is made of a nitride or carbonitride of Ti _a Cr _b Al _c Mo _1-abc , and the atomic ratio a 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 total film Since the thickness is in the range of 0.2 μm or more and 10.0 μm or less, Mo oxide is formed on the surface of the coating by containing Mo in the coating, and a coating with excellent welding resistance and high hardness is obtained. . 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. As a result, it is possible to obtain a coating film having excellent welding resistance and high hardness. 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 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.

The hard coating for a cutting tool of the present invention is a single layer film made of a nitride or carbonitride of Ti _a Cr _b Al _c Mo _1-abc , and the atomic ratio a is in the range of 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, and 1-abc is 0.1 or more. If the numerical value is out of the range, sufficient wear resistance and welding resistance cannot be obtained, and the tool life may be shortened. The atomic ratio a 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-ab- By setting c to 0.1 or more, a hard coating film having both excellent wear resistance and welding resistance can be formed.

  The total film thickness of the hard film for a cutting tool of the present invention is in the range of 0.2 μm or more and 10.0 μm or less, but is sufficient when the total film thickness of the hard film is less than 0.2 μm. While there is a possibility that the wear resistance and the welding resistance cannot be obtained, when it exceeds 10.0 μm, the toughness is likely to be reduced and chipping or peeling is likely to occur. It can be shortened. By setting the total film thickness within the range of 0.2 μm or more and 10.0 μm or less, it has a thickness sufficient to guarantee wear resistance and welding resistance, and is hard to prevent chipping or peeling. A coating can be constructed.

  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 single layer film, and the total film thickness d is in the range of 0.2 μm to 10.0 μm. Moreover, the said hard film 20 is comprised from the material which satisfies the chemical composition shown below. That is, it is a nitride or carbonitride of Ti _a Cr _b Al _c Mo _1-abc , the atomic ratio (mixed crystal ratio) a being in the range of 0.2 to 0.7, and b being 0.01 or more Within a range of 0.2 or less, c is within a range of 0.01 or more and 0.2 or less, 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 hard coating 20 of the present embodiment.

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 film structure and film thickness (total film thickness) of the test products 1 to 45 used in this test together with the test results (cutting distance and determination) of each test product. The inventors of the present invention coated a hard drill having a tool diameter of 6 (mmφ) with each coating structure and film thickness shown in FIG. A cutting test was performed under the conditions. Note that, among the test products 1 to 45 shown in FIG. 4, the test products 1 to 37 correspond to the products of the present invention to which the hard coating 20 of this example is applied, and the test products 38 to 45 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 38 to 45, the test products 38 and 39 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 40 to 45 are made of TiCrAlMoN. To which a hard coating is applied, which 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: S25C (JIS standard)
・ Cutting method: Hole machining ・ Cutting speed: 100 (m / min)
・ Feeding speed: 1061 (mm / min)
・ Processing depth: 16 (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 10 (m) or longer. Is indicated by ◯, and rejected products not satisfying the acceptance criteria are indicated by ×. As mentioned above, specimens 1 to 37 shown in FIG. 4 are both a single-layer film made of _{Ti a Cr b Al c Mo 1} -abc nitride _{(Ti a Cr b Al c Mo} 1-abc N) The atomic ratio a 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-a- The hard coating 20 of the present example, in which bc is 0.1 or more and the total film thickness is in the range of 0.2 μm to 10.0 μm, is applied. As a result of this test, it can be seen that these test products 1 to 37 all satisfy the above acceptance criteria and are cut well.

On the other hand, the test article 38 shown in FIG. 4 has a hard coating film of 10.0 (μm) made of Ti _0.48 Al _0.52 N, and the test article 39 has a film thickness of Ti _0.50 Al _{0.50 N5} . A hard film having a thickness of 0 (μm) is formed, and each corresponds to a non-invention product to which a conventional hard film is applied. As a result of this test, it can be seen that none of these test products 38 and 39 satisfied the above-mentioned acceptance criteria, and good cutting was not performed.

Further, the test product 40 shown in FIG. 4 is one in which a hard film having a thickness of 0.18 (μm) made of Ti _0.48 Cr _0.22 Al _0.009 Mo _0.29 N is formed, and the atomic ratio b of Cr is in the present invention. While deviating from the range of 0.01 or more and 0.2 or less, 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. Furthermore, the film thickness deviates from the range of 0.2 μm to 10.0 μm according to the present invention. As a result of this test, it can be seen that the test product 40 did not satisfy the acceptance criteria, and good cutting was not performed. From this result, it was verified that the atomic ratio b of Cr should be 0.2 or less, the atomic ratio c of Al should be 0.01 or more, and the film thickness should be 0.2 μm or more. Significance of the numerical range according to the present invention Was confirmed.

Further, a test article 41 shown in FIG. 4 is formed with a hard coating film having a film thickness of 10.0 (μm) made of Ti _0.71 Cr _0.01 Al _0.21 Mo _0.07 N, and the atomic ratio a of Ti is in the present invention. While deviating from within the range of 0.2 to 0.7, the atomic ratio c of Al deviates from within the range of 0.01 to 0.2 according to the present invention. Furthermore, the atomic ratio 1-abc of Mo is less than 0.1. As a result of this test, it can be seen that the test product 41 did not satisfy the acceptance criteria, and good cutting was not performed. From this result, it was verified that the Ti atomic ratio a should be 0.7 or less, the Al atomic ratio c should be 0.2 or less, and the Mo atomic ratio 1-abc should be 0.1 or more. The significance of the numerical range according to the present invention was confirmed.

Further, the test product 42 shown in FIG. 4 is one in which a hard film having a film thickness of 5.5 (μm) made of Ti _0.70 Cr _0.04 Al _0.21 Mo _0.05 N is formed, and the atomic ratio c of Al is in the present invention. While deviating from the range of 0.01 or more and 0.2 or less, the Mo atomic ratio 1-abc is less than 0.1. 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 was verified that the atomic ratio c of Al should be 0.2 or less, and the atomic ratio 1-abc of Mo should be 0.1 or more, and the significance of the numerical range according to the present invention was confirmed. It was.

Further, the test article 43 shown in FIG. 4 is formed by forming a hard film having a film thickness of 10.2 (μm) made of Ti _0.65 Cr _0.05 Al _0.15 Mo _0.15 N. It deviates from the range of 2 μm or more and 10.0 μm or less. 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, it was particularly verified that the film thickness should be 10.0 μm or less, and the significance of the numerical range according to the present invention was confirmed.

Further, the test product 44 shown in FIG. 4 is one in which a hard film having a thickness of 9.9 (μm) made of Ti _0.19 Cr _0.14 Al _0.05 Mo _0.62 N is formed, and the atomic ratio a of Ti is in the present invention. It deviates from within the range of 0.2 or more and 0.7 or less. 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, it was particularly verified that the atomic ratio a of Ti should be 0.2 or more, and the significance of the numerical range according to the present invention was confirmed.

Further, the test product 45 shown in FIG. 4 is formed with a hard film having a thickness of 5.5 (μm) made of Ti _0.31 Cr _0.33 Al _0.21 Mo _0.15 N, and the atomic ratio b of Cr is in the present invention. While deviating from the range of 0.01 or more and 0.2 or less, 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. 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 atomic ratio b of Cr should be 0.2 or less and the atomic ratio c of Al should be 0.2 or less, and the significance of the numerical range according to the present invention was confirmed.

As is clear from the above description, the result of this test shown in FIG. 4 shows that the film is a single layer film made of a nitride or carbonitride of Ti _a Cr _b Al _c Mo _1-abc and has an atomic ratio a of 0. .2 or more and 0.7 or less, b is 0.01 or more and 0.2 or less, c is 0.01 or more and 0.2 or less, and 1-abc is 0.1. In the cutting tool to which the hard coating 20 of the present embodiment, in which the total film thickness is in the range of 0.2 μm or more and 10.0 μm or less, is applied, good cutting performance can be obtained. It has been found that good cutting performance cannot be obtained in a cutting tool to which a hard coating having a deviating configuration is applied. 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 is a graph showing the results of tests conducted by the present inventors in order to verify the friction durability characteristics of the hard coating 20 of the present example. The present inventors create an example sample in which the well-known super indenter is coated with the hard coating 20 of the present embodiment and a comparative example sample in which the conventional hard coating is coated, and compare their friction durability characteristics. A test was conducted. That is, an example sample in which a single layer film having a thickness of 3.0 μm made of Ti _0.5 Cr _0.1 Al _0.1 Mo _0.3 N is applied as the hard coating 20 of the present embodiment, and Ti _0.5 Al _0.5 N is formed as a conventional hard coating. A comparative sample having a single layer film having a thickness of 3.0 μm was prepared, and a friction durability 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: 200 (g)
・ Friction speed: 250 (mm / s)
・ Friction time: 600 (s)
・ Temperature: 21 (℃)
・ Humidity: 52 (%)

In FIG. 5, as a result of the above-mentioned friction durability test, the result of the example sample provided with a single layer film having a thickness of 3.0 μm made of Ti _0.5 Cr _0.1 Al _0.1 Mo _0.3 N is represented by a solid line, from Ti _0.5 Al _0.5 N The result of the comparative example sample to which the single layer film having a thickness of 3.0 μm is formed is indicated by a broken line. As shown in FIG. 5, in the sample to which the hard film 20 of the present example was applied, the friction coefficient was approximately 40 to 50% over the test time of 600 (s) compared to the sample to which the conventional hard film was applied. As a result, a low value was exhibited and excellent friction characteristics (lubricity) were obtained. In addition, large peeling was seen in the conventional product. 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. It is a single layer film made of nitride, and the atomic ratio a is in the range of 0.2 to 0.7, b is in the range of 0.01 to 0.2, and c is 0.01 to 0.2. In this range, 1-abc is 0.1 or more, and the total film thickness is in the range of 0.2 μm or more and 10.0 μm or less. Therefore, by containing Mo in the film, Mo oxide is formed on the surface of the coating, and a high hardness coating is obtained while having excellent 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, a coating film having excellent welding resistance and high hardness can be obtained. 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 (hard coating coated cutting tool)
20: Hard film for cutting tool d: Total film thickness

Claims (2)

A hard coating for a cutting tool provided on the surface of a cutting tool,
A single layer film made of a nitride or carbonitride of Ti _a Cr _b Al _c Mo _1-abc ,
The atomic ratio a 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-ab- c is 0.1 or more,
And the hard film for cutting tools characterized by the total film thickness being in the range of 0.2 μm or more and 10.0 μm or less.   A hard coating-coated cutting tool, wherein the hard coating for a cutting tool according to claim 1 is coated on the surface.

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