JPH09117806A - Composite multilayer coated tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coat to improve adhesion with a base material by forming a multilayer film of a TiCN high hardness hard composite coat on a surface of a high speed tool as the base material, having high tenacity not to cause a defect while tool cutting by relaxing film stress and excellent in abrasion resistance. SOLUTION: A uniform organization of TiN or TiCN of total film thickness of a coated film of 2.0μm-6.0μm and of film thickness of 0.2μm-0.9μm structured of more than ten layers in multilayer constitution of a film with high speed tool steel as a base material is coated in a first layer as the lowest layer making contact with the base material. Additionally, TiCN is laminated on it as a second layer of 0.1μm-0.5μm in film thickness and TiN or TiCN is laminated on it as a third layer of 0.1μm-0.5μm in film thickness respectively, and thereafter, films of the same components as the second layer and the third layer of 1μm-0.5μm in film thickness are repeatedly laminated at least more than three times in order. The total number of layers is 10-20 by laminating TiCN of 0.2μm-1.0μm in film thickness on the top layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite multi-layer coated tool in which a composite multi-layer coating is applied to a tool body made of high-speed tool steel as a base material for the purpose of improving the life of a cutting tool.

[0002]

2. Description of the Related Art Conventional physical vapor deposition coated tools are Ti
It is applied to various cutting tools centering on N. In the physical vapor deposition method, ion plating or sputtering is used, and since coating at low temperature (up to 600 ° C) is possible, it is applied to tools using high speed tool steel or die steel as a base material. T
iN is a coating film having a relatively high toughness, but TiC and TiCN films are well known in addition to this in the Ti system.

TiCN has extremely high hardness and excellent wear resistance, but its characteristics change depending on the ratio of the carbon component and the nitrogen component.
A tool coated with, especially a milling tool, etc., may not be used because the cutting edge may be damaged. This is because the wear resistance is improved by increasing the hardness, but the strength is low and the shock resistance is low, so that the characteristics as high hardness is a drawback for application as a cutting tool. In order to make up for this drawback, for example, in Japanese Patent Publication No. 62-42995, a TiN film having a film thickness of 0.5 μm to 1.0 μm is first coated and then a TiC film or TiCN film having a film thickness of at least 1.0 μm or more.
Although the film is coated to have a two-layer structure, the film strength cannot be sufficiently secured by the method of laminating such a TiC film or TiCN film having a film thickness of 1.0 μm or more, and delamination may occur. Further, in Japanese Patent Laid-Open No. 6-101018,
At first, a TiN film having a film thickness of 0.1 μm to 3.0 μm is coated, and then the film strength is improved by a method of laminating three layers of TiN film and TiCN film. In the case of a film, sufficient film strength cannot be ensured and delamination may occur. In such a four-layer structure, the multi-layer effect is not exhibited and sufficient toughness cannot be obtained.

[0004]

An object of the present invention is to form a multilayer film of a TiCN-based high hardness hard composite coating on the surface of a tool made of high-speed tool steel as a base material to improve adhesion to the base material. (EN) It is intended to provide a coating film which has a high toughness to increase the film stress, relaxes the film stress and does not cause a chip during tool cutting, and has excellent wear resistance.

[0005]

For this reason, the present invention satisfies the following conditions (a) to (c) in a tool using a high-speed tool steel as a base material: (a) coating film composition Is a composite film composed of Ti, C, and N, and (b) the multilayer structure of the film has a structure of 10 or more layers,
The total thickness of the coating film is 2.0 μm to 6.0 μm,
The composition of the coating film is atomic ratio carbon ratio = C / (C + N) =
TiN or T having a film thickness of 0.2 μm to 0.9 μm as t
A uniform structure of iCN (0 ≦ t ≦ 0.2) is formed as a lowermost layer in contact with the base material on the first layer, and a second layer having a thickness of 0.1 to 0.5 μm is formed on the first layer. As TiCN
(0.3 ≦ t ≦ 0.7) and Ti as a third layer thereon
N or TiCN (0 ≦ t ≦ 0.2) is laminated, and thereafter, the films of the components of the second layer and the third layer each having a film thickness of 0.1 to 0.5 μm are sequentially repeated at least three times or more. By stacking TiCN (0.3 ≦ t ≦ 0.7) having a film thickness of 0.2 μm to 1.0 μm on the uppermost layer so that the total number of layers is 10 to 20. Characteristically, (c) the characteristics of the coated tool or the portion of the test piece of the same base material type that has been simultaneously processed with the same coating as the functional main part of the tool member are (1) the base material is 60 HRC. It has the above hardness and has a surface roughness of 1900 or more and 4000 HV or less and Ry of 5 μm or less with a 50 g micro Vickers hardness tester. (2) A normal C scale Rockwell hardness tester is used for the coating film. As a result of observing the indentation generated when pressed at a magnification of 100 times, Peeling of the film is not observed in the range of more sides around 1 mm. The problem of the prior art was solved by providing a composite multilayer coated tool characterized by satisfying the following conditions (a) to (c) in a tool using high-speed tool steel as a base material.

Atomic ratio of TiN or TiCN Carbon ratio = t
In the first layer, 0 ≦ t ≦ 0.2 is set to increase the adhesiveness with the base material and to suppress the increase of the film stress as much as possible, TiN (t = t = 0) or TiCN (0 <t ≦ 0.2) having a low carbon concentration is preferable. The reason why TiCN (0.3 ≦ t ≦ 0.7) is used for the second layer is that the TiCN coating shown in FIG. From the relationship between the carbon concentration and hardness of the coating film, the TiCN coating film must have the hardest coating and the densest coating structure in order to secure wear resistance. Is not sufficiently hard, and t>
At 0.7, the hardness of the coating is high, but the structure is not dense, so the range is limited to the above range. In addition, as shown in FIG. 1, the number of layers is 10 or more because the multilayer effect on the fracture resistance is not significant when the number of layers is 10 or less, and the strength of the film per layer is insufficient when the number of layers is 20 or more. This is because And the uppermost layer is the second layer of TiC
The reason why N (0.3 ≦ t ≦ 0.7) is set is that the cutting resistance of cutting can be reduced by forming the outermost surface of the tool with a high hardness coating. Further, the thickness of each layer of the composite multilayer tool of the present invention is set to 0.1 μm to 0.9 μm, because when the thickness is less than 0.1 μm, excellent welding resistance cannot be ensured, while This is because if the film thickness exceeds 0.9 μm, sufficient film strength cannot be ensured and delamination may occur. Further, the overall film thickness is set to 2.0 μm to 6.0 μm, because when the film thickness is less than 2.0 μm, excellent wear resistance cannot be secured, while when the film thickness exceeds 6.0 μm. This is because the cutting edge is easily damaged.

The present invention has been devised as a composite multilayer structure of coatings in order to maximize the use of the characteristics of a high hardness TiCN film for a cutting tool.
95 and Japanese Patent Laid-Open No. 6-101018 are completely different from the main point of the structure of the multilayer film. Ie TiC
It is known that N has a fine structure and a large film stress when it is formed into a film by ion plating or the like. (Proceedings of the 70th Ordinary General Meeting of the Japan Society of Mechanical Engineers, published by the Japan Society of Mechanical Engineers) [1993.3.31-4.2 Hachioji] 33
P. 1, 332). It is also shown in FIG. 2 that the hardness of the TiCN film increases as the carbon concentration increases. Therefore, when the TiCN film is applied to a tool, it is presumed that if the high hardness TiCN layer is thickened, the film stress will increase and the film itself will break from the gap in the stress state with the base material. Therefore, in the present invention, the thickness of the base material is 0.2 μm to 0.9 μm.
Adhesion is improved by arranging a TiN layer having a thickness of μm or a TiCN layer having a low carbon content, and a film thickness of 0.1 μm
By alternately depositing carbon components by alternately stacking with a high hardness TiCN layer containing a large amount of carbon of 0.5 μm, the increase in film stress is suppressed as much as possible, and TiCN is maintained without impairing toughness.
The film could be coated on the tool.

[0008] As described in "New Material" Vol.4 NO.10, pages 37 to 41, published by Nippon Kogyo Publishing Co., Ltd. in October 1993, it is empirical. c)
One of the criteria is the judgment of delamination by the Rockwell indentation method shown in. FIG. 3 shows a comparison of the films of the present invention, single layer and double layer, each shown in film configuration for a high speed tool steel end mill. In the case of a TiCN single layer having a film thickness of 3.0 μm and a TiN + TiCN laminated film having a film thickness of 3.0 μm, film breakage occurs due to the entry of a Rockwell indenter, but the present invention has 12 layers having a film thickness of 3.0 μm. The product did not peel and only micro cracks occurred.

The function of the present invention is to combine the high hardness TiCN film containing a large amount of carbon shown in FIG. 2 with TiN having high toughness or the composite film TiCN having a low carbon concentration to obtain a film thickness of 0.1 μm.
By realizing a multi-layered film having high hardness and high toughness by forming a multi-layered film having a thickness of up to 0.5 μm, by applying the multi-layered film to a cutting tool, it is possible to obtain high hardness materials and Enables cutting under high speed conditions.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

(Example 1) As an example of the present invention, an end mill having a high-speed tool steel as a base material was subjected to ion plating to obtain the results shown in Table 1.
The film was formed into the film structure shown in. The ion plating device was evacuated to 10 ^-2 Pa, and the processed product was heated by electron irradiation to 4
Heated to 00-500 ° C. After that, the surface of the object to be treated was cleaned with an argon ion bombardment, and then the coating treatment was performed. The coating is performed by introducing nitrogen and acetylene into a Ti evaporation source, in which case nitrogen is introduced to form a TiN layer, and then acetylene is increased while reducing nitrogen to form a TiCN layer. This was repeated for the number of layers, and each layer was formed by switching the mixing ratio of these two types of reaction gases and switching the opening and closing of the two types of reaction gases. Thus, in this way, 11 kinds of TiCN composite multilayer films of the present invention and various similar film constitutions for comparison were tested with a high speed tool steel end mill and a test piece of the same base material type.
Was formed into a film. When the test pieces of the same base material that were simultaneously treated were examined by the indentation peeling method, No. 10 was TiN layer and TiC
Peeling was confirmed in the N layer, but other than that, the outer circumference of the indentation was 1 m.
No peeling of the film was observed in the range of m or more. From the results of the cutting test, it was confirmed that the product of the present invention had a significant reduction in flank wear and corner wear as compared with the other comparative products.

[0011]

[Table 1]

(Example 2) Table 2 shows the results of a cutting test of a drill having a high-speed tool steel as a base material. Each of the drills was ion plating, and six kinds of films were formed by the same method as in Example 1. As a result, it was confirmed that the drill number of the TiCN multilayer film-coated drill of 10 or more layers of the present invention was significantly improved as compared with the comparative product.

[0013]

[Table 2]

(Embodiment 3) An embodiment of a gear cutting tool hob having a high speed tool steel as a base material will be described. FIG. 4 shows the results of cutting tests by forming hobs using the TiCN composite multilayer film of the present invention and the conventional TiN coating and TiN + TiCN coating by ion plating. Single-layer TiN with a thickness of 3.0 μm and Ti with a thickness of 1.5 μm
The hobs coated with two layers of N + 1.5 μm TiCN (however, (C / C + N) = 0.3) increase wear at an early stage, while 0.2 μm TiN and each film thickness of 0. 2 layers of (TiN + TiCN (however (C / C + N) = 0.3)) 8 layers +
The product of the present invention coated with 0.2 μm TiCN (however, (C / C + N) = 0.3) showed an improvement in wear resistance of 1.5 to 2.0 times.

[0015]

As described above, in order to effectively utilize the characteristics of a TiCN film containing a large amount of carbon and having a high hardness but a low surface toughness, with respect to a cutting tool using a high speed tool steel as a base material. , Relatively high toughness TiN or low carbon concentration T
By providing a method for constructing a composite multilayer having a film thickness of 0.1 μm to 0.5 μm in combination with iCN, it becomes possible to secure the adhesion with the base material and suppress the internal stress of the film. It was possible to improve wear resistance without causing chipping and chipping during cutting.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the structure of a composite multi-layer coated tool of the present invention.

FIG. 2 is a graph showing the relationship between the carbon concentration of the TiCN coating and the micro Vickers hardness of 50 g.

FIG. 3 is an explanatory diagram showing the results of judgment of delamination by Rockwell's indentation method for a film to be coated on a tool, showing the present invention, a single layer and a two-layer case, each showing a film configuration for a high-speed tool steel end mill. A comparison of membranes is shown.

FIG. 4 is a graph showing a cutting test result of forming a hob on which the TiCN composite multilayer film of the present invention product and the conventional TiN coating and TiN + TiCN coating are applied.

Claims (1)

[Claims] 1. A composite multi-layer coated tool characterized by satisfying the following conditions (a) to (c) in a tool using a high speed tool steel as a base material; It is a composite film composed of Ti, C, and N, and (b) the multilayer structure of the film has a structure of 10 layers or more, and the total film thickness of the coating film is 2.0 μm to 6.0 μm. The composition of the film is TiN or TiC having a film thickness of 0.2 μm to 0.9 μm with an atomic ratio of carbon ratio = C / (C + N) = t.
A uniform structure of N (0 ≦ t ≦ 0.2) is formed on the first layer as the lowermost layer in contact with the base material, and a second layer having a thickness of 0.1 μm to 0.5 μm is formed thereon. As TiCN
(0.3 ≦ t ≦ 0.7) and Ti as a third layer thereon
N or TiCN (0 ≦ t ≦ 0.2) is laminated, and thereafter, the films of the components of the second layer and the third layer having a film thickness of 0.1 μm to 0.5 μm are sequentially repeated at least three times or more. Layered, and the top layer has a film thickness of 0.2 μm to 1.0 μm.
m of TiCN (0.3 ≦ t ≦ 0.7) is laminated, and the total number of layers is 10 to 20 layers. (c) The coated tool or the same base material treated simultaneously with the coated tool The characteristics of the part where the test piece of the seed is coated equivalent to the functional main part of the tool member are as follows: (1) The base material has a hardness of 60 HRC or more, and is 1900 with a 50 g micro Vickers hardness meter. Above 4000 HV
Below, the surface roughness is Ry 5 μm or less, and (2) the result of observing the indentation generated when the ordinary C-scale Rockwell hardness meter is pressed against the coating film at a magnification of 100 times, shows that the outer periphery of the indentation No peeling of the film is observed in the range of 1 mm or more.