JPH11246961A - Coated tool with laminated film and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently thicken a film and to reduce the residual stress in a tool by composing metallic components to be used at least of two of Ti and Al, using two kinds of reactive gas components and regulating the residual compressive stress of a laminated film to the one equal to or below that of TiN and TiCN. SOLUTION: As the reactive gas components, the combination of nitrogen and oxygen is preferable. This laminated film exhibits high adhesion even to a high speed steel and a cermet alloy becaused of its extremely small residual compressive stress. Moreover, by the laminated film, the propagation of cracks generated on the surface of the film in the process of cutting in the boundary of the film is suppressed. Simultaneously, in the case the cracks moreover progress, they propagate along the boundary, and the propagation to a substrate and the chipping of blade edges caused thereby are suppressed. thus, the coated tool with the laminated film has high wear resistance by the thickening of the film and simultaneously has high toughness since cracks hardly propagate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated hard tool having excellent wear resistance.

[0002]

2. Description of the Related Art In general, in order to obtain a thick film, a laminated coating is usually manufactured by changing its metal component and fixing a gas component. Although various combinations of metal components are possible, gas components require control of the atmosphere, making it difficult to change them in a short time, and have not been studied because they lack uniformity. When the thickness of the ion plating film is increased, the film has a preferential growth orientation in crystal growth, and as a result, a film having a columnar crystal structure is formed. When one columnar crystal grain is taken out, it is a single crystal in which strong crystal growth is observed in a certain direction, and the number of internal defects is extremely small. The reason is that the residual compressive stress increases as such crystals are continuously formed and the thickness of the film increases. For that, 1
It is sufficient to reduce the thickness of one layer, but there is a limit to the combination with other metal components. As an example of a combination of metal components, there is JP-A-7-97679 in which TiN and AlN are combined, and the superlattice film is improved in its properties, particularly in hardness.

[0003]

However, the characteristics of the superlattice film described in the prior art are remarkably changed. In particular, although the superlattice film has improved hardness, the residual stress is high, and the superlattice film is used as a cutting tool. When used, it was not satisfactory in performance due to peeling between layers.

[0004]

The object of the present invention is to provide a cutting tool which can achieve a sufficiently thick film without reducing the superlattice, provide a laminated film with reduced residual stress, and provide sufficient wear resistance. The purpose is to:

[0005]

Means for Solving the Problems The inventors of the present invention have proposed a method for reducing the residual compressive stress and increasing the thickness of an ion-plated film, and consequently improving the wear resistance. It has been found that by coating two or more kinds of films by laminating different gas components, the film thickness can be increased without increasing the residual compressive stress. Therefore, in the present invention, in a laminated coating tool comprising 10 to several thousand layers, at least two metal components are used, Ti and Al, and two gas components are used. Is 3 GPa or less, and more specifically, the gas component is a combination of nitrogen and oxygen, or a combination of nitrogen and carbon. Further, the present invention provides a method for producing a laminated coated tool, characterized in that one of the gas components is intermittently flowed to form a film, and the compounds of Ti and Al form carbides, nitrides, oxides, borides and the like, respectively. In addition, a compound having an intermediate composition can be produced in the same manner, and since the crystal structures are similar, there is no remarkable property change such as a superlattice, but the adhesion between layers is excellent. In particular, when the gas system is changed, the gas components are not instantaneously replaced. In other words, since the intermediate compound layer is formed extremely thin, the adhesion between the layers is excellent.

[0006]

The use of Ti and Al as metal components is a component generally used in TiAlN films and the like at present, but is not used as a conventional example but as a metal solid solution compound. In addition, the reason why two or more gas components are used is that some similar characteristics are required for lamination, so that adjacent elements in the periodic table such as boron and carbon, carbon and nitrogen, and nitrogen and oxygen are used. Good combination. Further, since the laminated coating according to the present invention has an extremely small residual compressive stress as described above, it exhibits extremely high adhesion to high-speed steel and cermet alloys.
Generally, a film of ion plating generates a compressive stress during coating. Further, since high-speed steel and cermet alloy have a larger thermal expansion coefficient than the film, a compressive stress is further applied to the film in a cooling step after coating. As a result, when taken out at room temperature, it has a much higher compressive stress than in the case of a cemented carbide substrate, and as a result, the adhesion is significantly deteriorated. Such a problem is also solved by the laminated film of the present invention.

Further, the cracks generated on the coating surface during cutting by the laminated film tend to be suppressed at the interface of the coating, that is, the stress concentration generated at the crack tip is reduced by a large number of lattice defects at the interface. Are relaxed and exhibit high resistance to crack propagation. At the same time, when the crack further develops, the crack propagates along the interface and largely suppresses the propagation to the base and the resulting loss of the cutting edge. Therefore, the laminated coated hard tool according to the present invention has high wear resistance due to thickening, and has high toughness at the same time since cracks are hardly propagated. Therefore, it goes without saying that the tool life is improved not only when the film is thick but also when it is relatively thin.

Hereinafter, the reasons for limiting the numerical values will be described. Unless 10 or more layers are provided, the thickness of each layer becomes too large, so that effects such as stress and cracks are not sufficient, and a thickness of about 1 to 10 microns is practical for use as a tool. It is desirable to alternately stack the layers at intervals of less than 0.1 micron. If the thickness is too thin, such as less than 10 nm, the gas system will not be completely switched and the properties of the film itself will be intermediate and the lamination effect will not be exhibited. If it exceeds 100 nm, the thickness as a single layer will be too thick. The thickness was set to 10 to 100 nm because it was too much.

If the residual compressive stress exceeds 3 GPa, chips such as chipping and peeling are likely to occur due to the load during cutting. Therefore, the residual compressive stress is set to 3 GPa or less. In addition, when a third metal element is added to a target material or the like for various purposes, its characteristics can be improved, which is useful. For example, to improve the hardness of the coating itself, use S
The addition of i, Zr, etc. is effective, and is improved by adding Y, Nd, etc. to increase the resistance to oxidation. Hereinafter, the present invention will be described based on examples.

[0010]

EXAMPLE A coated insert made of cemented carbide was manufactured by coating a throw-away tip made of an alloy equivalent to JIS P30 with a small arc ion plating apparatus. did.
In addition, as an example of the present invention, a description will be made using a throw-away tip.
The reason for this is that the cutting speed can be increased because the diameter is larger than that of a drill or the like, and a sufficient effect is obtained in a solid drill, an end mill, or the like. The coating parameters at the time of deposition were a bias voltage of −300 V, a reaction gas pressure of 4 × 10 ⁻² mbr, and a target of Ti
A 50% Al 50% sintered target is used, and the reaction system gas is nitrogen gas for nitride film formation, methane gas for carbide film formation, oxygen gas or oxide gas or water vapor content control for oxide film formation, etc. Is mainly used, but carbon monoxide gas and carbon nitride gas can be used at the time of carbonitride film formation, diborane or the like can be used at the time of boride film formation, or a combination of the above-mentioned gases can be used. The film was formed by intermittently flowing another composite gas for a short time. First, using nitrogen gas and oxygen gas, oxygen gas was intermittently flowed for a certain period of time, and the flow rate was changed to prepare samples in which the ratio of N: O was variously changed. Table 1 shows the results.

[0011]

[Table 1]

After measuring the residual stress by using the obtained coated TA chip, the test was carried out in air at 100 to test the oxidation resistance.
It was kept at 0 ° C. for a predetermined time, and its fracture surface was observed. The results are also shown in Table 1. As is clear from Table 1, in the laminated example (sample numbers 1 to 8), the residual stress can be reduced to the same level as that of the TiN single layer film, and the progress of oxidation is completely different. Although oxidation of the surface progressed, almost no oxidation was observed inside the film, and only the effect of heat was observed, whereas in the latter, the change in film quality due to oxidation was observed by almost half.

Further, in the same manner as in the example, a test was similarly performed using the coating parameters shown in Table 2, and the test was performed using methane gas and nitrogen gas. Table 2 shows the results.

[0014]

[Table 2]

After the residual stress was measured using the obtained coated TA chip, the micro Vickers hardness was measured. The results are also shown in Table 1. As is clear from Table 1, in the laminated example (sample numbers 11 to 18), the residual stress was Ti
It can be reduced to the same degree as a CN monolayer film,
Vickers hardness could be improved to a value close to 3000.

Next, Sample Nos. 1, 4, 5, 1
4, 16, and 17 and Sample Nos. 10, 18, and 2 of Comparative Examples
Using 0, cutting was performed under the following cutting specifications, and the flank wear after 10 m cutting was measured. The work material is SKD61 (HR
C42, width 100 mm x length 250 mm), cutting speed 200 m / min, feed amount 0.15 m / blade, and cutting depth 1.5 mm. As a result, the six samples of the present invention example
The average flank wear after cutting for 10 minutes is 0.18 mm to 0.1 mm.
While no chipping or peeling of the film was observed at 2 mm, the sample number 10 of the comparative example exceeded 0.4 mm,
18 was a large value of 0.6 mm due to peeling and chipping. In the case of No. 20, the wear amount was as large as 0.38 mm.

[0017]

According to the present invention, by using the same kind of metal target and depositing and laminating with different gas systems,
Adhesion between the respective layers is remarkably improved, and the path of crack propagation is different due to the lamination of the films, so that a long-life coated tool in which the coated layer is hardly broken or peeled can be obtained.

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[Procedure amendment]

[Submission date] May 26, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

Means for Solving the Problems The inventors of the present invention have proposed a method for reducing the residual compressive stress and increasing the thickness of an ion-plated film, and consequently improving the wear resistance. It has been found that by coating two or more kinds of films by laminating different gas components, the film thickness can be increased without increasing the residual compressive stress. Therefore, in the present invention, in a laminated coating tool comprising 10 to several thousand layers, at least two metal components are used, Ti and Al, and two reactive gas components are used. A laminated coated tool, wherein the compressive stress is equal to or less than TiN, TiCN,
More specifically, the reactive gas component is a combination of nitrogen and oxygen, or a combination of nitrogen and carbon. Further, the present invention provides a method for producing a laminated coated tool, characterized by intermittently flowing one of the reactive gas components to form a film.
The compounds of Al form carbides, nitrides, oxides, borides, etc., respectively, and compounds of intermediate composition can be formed in the same manner, and since their crystal structures are similar, they have a superlattice-like structure. Although there is no significant change in properties, it has excellent layer-to-layer adhesion.Especially, when changing the reactive gas system, the reactive gas component is not instantaneously replaced, in other words, an intermediate compound. Since the layer is formed extremely thin, the adhesion between the layers is excellent.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006]

The use of Ti and Al as metal components is a component generally used in TiAlN films and the like at present, but is not used as a conventional compound but as a metal solid solution compound. Also, as a reactive gas component,
The reason why two or more types are used is that some similar characteristics are required for lamination, and therefore, a combination such as boron and carbon, carbon and nitrogen, and nitrogen and oxygen, which are adjacent elements in the periodic table, is preferable. Further, since the laminated coating according to the present invention has an extremely small residual compressive stress as described above, it exhibits extremely high adhesion to high-speed steel and cermet alloys. Generally, a film of ion plating generates a compressive stress during coating. Further, since high-speed steel and cermet alloy have a larger thermal expansion coefficient than the film, a compressive stress is further applied to the film in a cooling step after coating. As a result, when taken out at room temperature, it has a much higher compressive stress than in the case of a cemented carbide substrate, and as a result, the adhesion is significantly deteriorated. Such a problem is also solved by the laminated film of the present invention.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

The residual compressive stress is TiN, TiCN.
If it exceeds that, chipping, peeling and other defects are likely to occur due to the load at the time of cutting, so the residual compressive stress was set to be equal to or less than that of TiN and TiCN. In addition, when a third metal element is added to a target material or the like for various purposes, its characteristics can be improved, which is useful. For example, the addition of Si, Zr or the like is effective in improving the hardness of the coating itself, and is improved by adding Y, Nd or the like in order to increase resistance to oxidation. Hereinafter, the present invention will be described based on examples.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

After measuring the residual stress by using the obtained coated TA chip, the test was carried out in air at 100 to test the oxidation resistance.
It was kept at 0 ° C. for a predetermined time, and its fracture surface was observed. The results are also shown in Table 1. Example of lamination (sample numbers 1 to 8)
In this case, the residual stress can be reduced to the same level as that of the TiN single layer film, and the progress of oxidation is completely different. In the former case, oxidation of the outermost surface proceeds, but almost no oxidation occurs inside the film. In the latter case, the change in film quality due to oxidation was observed to almost half in the latter case.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

After the residual stress was measured using the obtained coated TA chip, the micro Vickers hardness was measured. The results are also shown in Table 2. Example of lamination (Sample No. 11
18), the residual stress can be reduced to the same level as that of the TiCN single-layer film, and as is clear from Table 2,
Vickers hardness could be improved to a value close to 3000.

Claims (4)

[Claims] 1. A laminated coated tool comprising 10 to several thousand layers, wherein at least two metal components are used, Ti and Al, and two gas components are used, and the residual compressive stress of the laminated coating is A laminated coated tool having a pressure of 3 GPa or less. 2. The laminated hard-coated tool according to claim 1, wherein the gas component is nitrogen or oxygen. 3. A laminated coating tool comprising 10 to thousands of layers, wherein at least two metal components are used, Ti and Al, and two types of gas components.
A method of manufacturing a laminated coated tool, characterized by intermittently flowing a film to form a film. 4. The method for producing a laminated hard-coated tool according to claim 3, wherein the gas component is nitrogen or carbon.