JP3248897B2 - Hard coating tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard film-coated tool used for cutting metal materials and the like.

[0002]

2. Description of the Related Art Conventionally, cutting tools coated with TiN, TiCN and the like have been widely used. Since TiN has relatively excellent oxidation resistance, it not only exhibits excellent wear resistance against tool rake surface wear caused by heat generated during cutting, but also has good adhesion to the base material. It is.
Moreover, since TiCN has a higher hardness than TiN, it exhibits excellent characteristics with respect to flank wear of a tool. However, in response to the tendency to increase the cutting speed for the purpose of increasing the efficiency of metal working, the hard coating does not exhibit sufficient oxidation resistance and wear resistance. From such a background, studies have been made to further improve the oxidation resistance and abrasion resistance of the coating. As a result, JP-A-62-56565 and JP-A-2-19415 have been studied.
No. 9 has been developed and applied to cutting tools.

[0003]

The TiAlN film has a Vickers hardness of approximately 2300 to 2800, although it varies depending on the component ratio of Ti and Al contained in the film. Since it is superior to TiN and TiCN, it greatly improves the performance of the cutting tool under cutting conditions in which the cutting edge reaches a high temperature. However, in recent years, in addition to the tendency for the cutting speed to be further increased, dry cutting is regarded as important in terms of environmental issues, and the use environment of cutting tools is becoming increasingly severe. According to the study by the present inventors, the oxidation start temperature of the TiAlN film in the air is increased from 750 ° C. to 750 ° C. to 900 ° C. depending on the amount of Al added to 450 ° C. of TiN. However, in the above-described dry high-speed cutting, the temperature of the cutting edge of the tool to be used reaches a high temperature of 900 ° C. or more.
At present, sufficient tool life cannot be obtained with the iAlN coating.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is intended to improve the oxidation resistance and wear resistance of a conventional TiAlN film and to cope with a dry and high-speed cutting process. It is an object to provide a hard film coated tool.

[0005]

The inventors of the present invention have conducted detailed studies on the effects of various elements on the oxidation resistance, abrasion resistance and adhesion of a hard coating and the layer structure of the coating. A nitride mainly containing Ti containing an appropriate amount of
Carbonitride, oxynitride or oxycarbonitride (hereinafter TiSi
And nitrides mainly composed of Ti and Al, carbonitrides, oxynitrides or oxycarbonitrides (hereinafter referred to as Ti
Al-based nitride) is coated with a coating in which the metal component contained in the alloy is limited to a specific value, and the coating is alternately coated one or more times. At this time, the coating of the TiAl-based nitride or the like is directly above the surface of the base material, And the microstructure structure of TiSi-based nitride or the like
By forming a film such that Si ₃ N ₄ and Si are present as independent phases in a nitride, carbonitride, oxynitride or oxycarbonitride containing The present inventors have found that the performance of a cutting tool is extremely good, and have reached the present invention.

That is, the present invention relates to high-speed steel, cemented carbide,
Either cermet or ceramics as a base material, layer a of the hard coating is atomic% of only metal component, Si is 10% or more and 60% or less, B, Al, V, Cr, Y, Zr, Nb, M
one or more of o, Hf, Ta, and W, less than 10%, and the remaining Ti is a nitride, carbonitride, oxynitride, or oxycarbonitride, and is composed of Si ₃ N ₄ and Si exists in the compound as an independent phase, and in the b layer, the atomic% of the metal component alone is more than 40% and 75% or less of Al: B, S
i, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W
One or two or more of the following, less than 10%, with the balance being Ti: nitride, carbonitride, oxynitride, or oxycarbonitride, wherein the a layer and the b layer are alternately at least one layer each And the b layer is located just above the surface of the base material, and the hard film is preferably coated by a physical vapor deposition method.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION First, the constituent requirements of the layer a described in the claims will be described in detail. Generally Ti
When an oxidation test is performed on the AlN film in the air, Al near the surface of the film diffuses outward to the outermost surface, where an alumina layer is formed. According to the study of the present inventors, this is considered to be the reason for improving the oxidation resistance. At this time, a very porous Ti oxide containing no Al is formed immediately below the alumina layer. In the static oxidation test, the alumina layer formed on the outermost surface functions as an oxidation protective film against the inward diffusion of oxygen, which is the progress of oxidation. The alumina layer is easily separated from the porous Ti oxide layer immediately below the alumina layer, and does not exert a sufficient effect on the progress of oxidation. However, TiSi-based nitrides and the like not only have extremely high oxidation resistance of the film itself, but also form a very dense composite oxide layer containing Si that serves as an oxidation protection film on the outermost surface.
Immediately below it, a porous T which causes the oxidation protective film to peel off
It was confirmed that no i-oxide was formed. In order to obtain the above-mentioned effect, Si is 10% by atomic% of only the metal component of the film.
If the content exceeds 60%, on the other hand, the ductility or the hardness of the film is remarkably reduced, and the film cannot be used as a cutting tool.

The B, Al, V, Cr, Y,
Zr, Nb, Mo, Hf, Ta, and W act as solid solution strengthening elements in a film such as a TiSi-based nitride and are effective in increasing the hardness of the film. B, Al, V, C as required
It is desirable to add one or more of r, Y, Zr, Nb, Mo, Hf, Ta, and W in trace amounts. However, if 10% or more of the atomic percentage of only the metal component of the coating is added, the effect of improving the oxidation resistance due to the Si content described above cannot be obtained. Therefore, B, Al, V, Cr, Y, Zr, N
b, Mo, Hf, Ta, W are one kind or two or more kinds,
Less than 0%. Further, the microstructure of the a-layer has a structure in which Si ₃ N ₄ and Si are present as independent phases in a nitride, carbonitride, oxynitride or oxycarbonitride containing Ti as a main component. , High hardness can be achieved, and a film having remarkably excellent wear resistance can be obtained. In order to form a film having such a structure, that is, the layer a of the present invention, differences in physical vapor deposition methods such as an arc discharge type ion plating and sputtering, and the basic method of a film forming apparatus even with the same method. Although the absolute value differs depending on the specification, the bias voltage applied to the substrate during coating is -10 to -100 V
This can be achieved by setting a relatively low value.

The role of Al in the b layer is to improve the wear resistance and oxidation resistance of the film. The lower the Al content in the coating, the better the adhesion between the base material and the coating. However, the atomic percentage of the metal component of the coating alone is 40%.
If it is less than the above, the effect of improving the wear resistance and oxidation resistance of the film cannot be obtained. However, if the content exceeds 75%, not only the adhesion between the base material and the film is deteriorated, but also the hardness of the film is lowered, and the wear resistance required for a tool cannot be obtained. Therefore, in order to obtain a good balance of adhesion, abrasion resistance and oxidation resistance, it is important to adjust the Al content of the b layer to be more than 40% and not more than 75% by atomic% of only the metal component of the film. It is. B, Si, V, Cr, Y, Z
r, Nb, Mo, Hf, Ta, and W act as solid solution strengthening elements in a film such as a TiAl-based nitride and are effective in increasing the hardness of the film. Therefore, if necessary, B, Si,
V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W
It is desirable to add a kind or two or more kinds in trace amounts. However, if 10% or more is added in atomic% of only the metal component of the film, the adhesion between the base material and the film is reduced. Therefore, B, Si, V, Cr, Y, Zr, Nb, Mo, and H are necessary to obtain a good balance of adhesion, abrasion resistance, and oxidation resistance.
f, Ta, and W are one or two or more and less than 10%.

As described above, in the present invention, a layer b having a good balance between adhesion to the base material, abrasion resistance and oxidation resistance of the film itself is coated directly on the base material surface, and a significantly acid-resistant layer is formed thereon. It is extremely important to coat the layer a, which is excellent in wearability and wear resistance, and as a result, it becomes possible to obtain a cutting tool corresponding to dry high-speed cutting. The same effect can be obtained by a multilayer coating in which a layer b and a layer b are alternately laminated after coating the layer b directly on the surface of the base material. In addition, each layer may include nitride, carbonitride, oxynitride,
It can be adjusted to any of oxycarbonitrides, and the same effect can be obtained for tools coated with them. The method for coating the hard film-coated tool of the present invention is not particularly limited, but the thermal effect on the coated base material, the fatigue strength of the tool, the adhesion of the film, and the matching between the a layer and the b layer are not particularly limited. When considering the properties, etc., it is possible to coat at a relatively low temperature, and the arc discharge type ion plating that compressive stress remains in the coated film,
Alternatively, a physical vapor deposition method of applying a bias voltage to the coating base material side such as sputtering is preferable. Hereinafter, the present invention will be described based on examples.

[0011]

[Embodiment] Using a small arc ion plating device
Various alloy targets, which are evaporation sources for metal components,
The reaction gas N₂Gas, CH₄Gas, Ar
/ O ₂Select the one that can obtain the target film from the mixed gas
And a coating substrate temperature of 400 ° C. and a reaction gas pressure of 3.0 Pa.
Under the conditions, the coated substrate 6
Full coating on single-flute end mills and cemented carbide inserts
Was formed so as to have a thickness of 4 μm. In addition,
All of the clear examples and Comparative Examples 51, 52, 53, 54, 55,
For 56, 57 and 58, a bias voltage of -30V
Was applied, and in Comparative Example 59, -200 was applied.
A bias voltage of V was applied to form a film. In addition,
In all cases, a bias voltage of -100 V is applied to form a film.
Was.

Using the obtained hard film-coated end mill and insert, processing is performed under the following dry high-speed cutting conditions until the tool cannot be cut due to chipping or wear of the cutting edge, and the cutting length at that time is determined by the tool life. And The cutting specifications of the end mill are as follows: side cut down cut, work material SKD11 (60HRC), cutting speed 200m / mi
n, feed amount 0.03 mm / tooth, cutting amount Ad = 12 m
m, Rd = 0.2 mm using air blow.
The cutting specifications of the insert were 100 mm in width using a face mill (insert shape = SEE42TN) with a diameter of 160 mm.
mm x 250 mm length plane processing, work material: SKD6
1 (45 HRC) at a cutting speed of 200 m / min, a feed amount of 0.15 mm / blade, and a cutting amount of 2.0 mm. Table 1 shows examples of the present invention, Table 2 shows comparative examples, and Table 3 shows details of hard coatings of conventional examples and cutting results thereof. a
For the presence or absence of Si ₃ N ₄ and Si in the layer, use XPS
To confirm that Si ₃ N ₄ and / or Si
The films in which the presence of was recognized are described in the table.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

[Table 3]

From Tables 1, 2 and 3, the present invention example
The tool life is remarkably improved as compared with the comparative example and the conventional example, and it can be seen that the tool life is sufficiently compatible with dry high-speed cutting. In Comparative Example 52, the composition of the film is included in the present invention. However, since the layer structure of the film is different, peeling of the film occurs early in cutting of the end mill, the insert, and both tools, resulting in a very short life. It became. Comparative Example 59
Indicates that the composition and layer structure of the film are included in the present invention. However, since only the Si phase is present in the a layer, sufficient film hardness cannot be obtained and the Life has expired. Further, when the Al content of the b layer was extremely large as in Comparative Example 57, peeling occurred at the interface between the base material and the b layer during cutting, resulting in an extremely short life.

[0017]

As described above, the hard-coated tool of the present invention has superior oxidation resistance and wear resistance as compared with the conventional coated tool, so that the tool life in dry high-speed cutting is significantly longer. This is extremely effective in improving productivity in cutting.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B23B 27/14 B23C 5/16 C23C 14/06

Claims (2)

(57) [Claims] A high-speed steel, cemented carbide, cermet, or ceramic is used as a base material, and an a layer of a hard coating is an atomic% of only a metal component, and Si is 10% or more and 60% or less, and B,
Al, V, Cr, Y, Zr, Nb, Mo, Hf, Ta,
One or more of W and less than 10%, the rest being any of nitrides, carbonitrides, oxynitrides, oxycarbonitrides composed of Ti, with Si ₃ N ₄ and Si as independent phases The b layer is present in the compound and the atomic% of the metal component alone is Al:
Over 40% and up to 75%, B, Si, V, Cr, Y, Z
one or more of r, Nb, Mo, Hf, Ta, and W, which is less than 10%, and the rest is any of nitride, carbonitride, oxynitride, and oxycarbonitride, The a layer,
A hard-coated tool, characterized in that the b-layers are alternately coated one or more times, and the b-layer is directly above the surface of the base material. 2. The tool according to claim 1, wherein said hard coating is coated by physical vapor deposition.