JP3248898B2 - 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 referred to as TiS
It is referred to as i-based compound or the like. ) And a film in which a metal component contained in a nitride, carbonitride, oxynitride or oxycarbonitride (hereinafter, referred to as TiAl-based compound or the like) mainly containing Ti and Al is limited to a specific value. Are alternately coated one or more times, and at this time, the film of the above-mentioned TiAl-based compound is formed directly on the surface of the base material, and the lattice constant of the TiSi-based compound is 0.417 nm or more and 0.423 nm or less. By doing so, it was found that the performance of the cutting tool was extremely good in dry high-speed cutting, and the present invention was reached. That is, the present invention uses any of high-speed steel, cemented carbide, cermet, and ceramics as a base material,
The layer is composed of atomic% of metal component only, and Si is 10% or more and 60%.
Hereinafter, B, Al, V, Cr, Y, Zr, Nb, Mo, H
One or more of f, Ta, and W is less than 10%, and is a nitride, carbonitride, oxynitride, or oxycarbonitride composed of remaining Ti, and has a NaCl-type crystal structure. And
And the lattice constant is 0.417 nm or more and 0.423 nm or less, and the b layer of the hard film has an atomic% of only the metal component
Al: more than 40% and 75% or less, B, Si, V, Cr,
One or two of Y, Zr, Nb, Mo, Hf, Ta, W
A nitride or carbonitride, oxynitride or oxycarbonitride composed of at least 10% and less than 10% of the remaining Ti, having a NaCl-type crystal structure, wherein each of the a layer and the b layer is at least one layer. It is preferable that the hard coating is alternately coated and the b layer is provided immediately above the surface of the base material, and the hard coating is coated by physical vapor deposition.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, when an oxidation test is performed in the atmosphere on a TiAlN film, 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 directly under the porous Ti
It easily peels off from the oxide layer and does not exert a sufficient effect on the progress of oxidation. However, TiSi-based compounds and the like not only have extremely high oxidation resistance of the film itself,
It was confirmed that a very dense composite oxide layer containing Si serving as an oxide protective film was formed on the outermost surface, and that a porous Ti oxide causing peeling of the oxide protective film was not formed immediately below. . In order to obtain the above effect, Si must be contained in an amount of 10% or more in atomic% of only the metal component of the film. Conversely, if it exceeds 60%, the decrease in ductility or hardness of the film is remarkable. And cannot be used as a cutting tool.

[0007] 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 compound and are effective in increasing the hardness of the film. Therefore, if necessary, B, A
1, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W
It is desirable to add one or more of these 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,
One or more of Zr, Nb, Mo, Hf, Ta, and W are less than 10%. Further, the a layer can achieve high hardness by setting the lattice constant to be 0.417 nm or more and 0.423 nm or less, and a film having extremely excellent wear resistance can be obtained. According to the study by the inventors, in the component range described in the claims, the lattice constant of a single a-layer is 0.424-0.
426 nm, and the lattice constant of a single b layer is 0.415
The single b-layer is extremely small, at ~ 0.417 nm. However, the layer a and the layer b are alternately coated one or more times, and the bias voltage applied to the substrate at that time is controlled to an appropriate value, so that the layer a and the crystal lattice level To match. As a result, the crystal lattice of the a-layer is smaller than that of a single layer, and a
The layer undergoes lattice distortion and its hardness increases. When coating the a layer and the b layer, the bias voltage applied to the substrate is different from the physical vapor deposition method such as the arc discharge type ion plating and sputtering, and the basic specification of the film forming apparatus even if the same method is used. Although the absolute value differs depending on the type, the matching of the crystal lattice at the interface between the a layer and the b layer can be achieved by forming both layers at an approximate bias voltage.

Next, 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.
If l is 40% or less, 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, the Al content of the b layer should be over 40% and 75% by atomic% of only the metal component of the film.
It is important to adjust the following. B, Si, V, C
r, Y, Zr, Nb, Mo, Hf, Ta and W are TiA
It acts as a solid solution strengthening element in a film such as an l-compound and is effective in increasing the hardness of the film. Therefore, B, Si, V, Cr, Y, Zr, Nb, Mo, Hf,
It is desirable to add a trace amount of one or more of Ta and W. However, the atomic percentage of only the metal component of the coating is 1
Addition of 0% or more lowers the adhesion between the base material and the film.
Therefore, in order to obtain a good balance of adhesion, abrasion resistance and oxidation resistance, B, Si, V, Cr, Y, Zr, Nb,
Mo, Hf, Ta, and W are one kind or two or more kinds and less than 10%.

As described above, in the present invention, a b-layer having a NaCl-type crystal structure having a good balance of adhesion to the base material, abrasion resistance and oxidation resistance of the film itself is coated directly on the base material surface, It is extremely important to coat the layer a, which is remarkably excellent in oxidation resistance and wear resistance, on the layer with the same NaCl-type crystal structure as the layer b. As a result, a cutting tool corresponding to dry high-speed cutting is obtained. It becomes possible. 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 can be adjusted to any of nitride, carbonitride, oxynitride, and oxycarbonitride as necessary, and the same effect can be obtained for a tool coated therewith.

The method of coating the hard film-coated tool of the present invention is not particularly limited, but the heat influence on the coated base material, the fatigue strength of the tool, the adhesion of the film, and the a layer and the b Considering the layer consistency, etc., the coating can be applied at a relatively low temperature and compressive stress remains in the coated film. An arc discharge type ion plating or a physical vapor deposition method that applies a bias voltage to the coating base material side such as sputtering. It is desirable that 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 light examples and Comparative Examples 54, 55, 56, 58, 59
The same level of -100 V was applied to both the layer a and the layer b.
Films were formed by applying an ias voltage.
For layers 3 and 57, the layer a is −30 V and the layer b is −200.
A bias voltage different from V was applied to form a film.
Further, in the conventional example, the bias voltage of
Pressure was applied to form a film. End mill with hard coating obtained
And inserts to meet the following dry high-speed cutting conditions
The tool cannot be cut due to chipping or wear of the cutting edge.
Machining until the cutting length is equal to the tool life.
Was.

The cutting specifications of the end mill are as follows: side cut down cut, cuts a workpiece SKD11 (60HRC) at a cutting speed of 200 m / min, feed amount 0.03 mm / tooth, cutting amount Ad = 12 mm, Rd = 0. This was performed using an air blow at 2 mm. The cutting specifications of the insert are 16
0 mm face mill (insert shape = SEE42T)
N), a plane processing of width 100 mm × length 250 mm was performed with a work material: SKD61 (45HRC) at a cutting speed of 200 m / min, a feed amount of 0.15 mm / blade, and a cutting amount: 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. The lattice constant in the a layer was calculated by X-ray diffraction. Table 3 also shows the results.

[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 51, 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 5
Nos. 3 and 57 are included in the present invention with respect to the composition and layer structure of the film, but since the lattice constant of the a layer is not satisfied, sufficient film hardness cannot be obtained, and the film thickness is shorter than that of the present invention. Life has expired.

[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 nitride, carbonitride, oxynitride or oxycarbonitride composed of Ti, having a NaCl-type crystal structure, and a lattice The constant is comprised between 0.417 nm and 0.423 nm,
The b layer of the hard coating has an atomic percentage of only the metal component of Al: 40%.
%, 75% or less, B, Si, V, Cr, Y, Zr, N
b, Mo, Hf, Ta, W or one or more of 10
%, Any of a nitride, carbonitride, oxynitride, or oxycarbonitride composed of the remaining Ti, having a NaCl-type crystal structure, wherein the a layer and the b layer are alternately coated one or more times. And a hard-film-coated tool, wherein the b layer is located immediately above the surface of the base material. 2. The tool according to claim 1, wherein said hard coating is coated by physical vapor deposition.