JP3016702B2 - Coated hard alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated cutting tool used as a cutting tool having excellent wear resistance and chipping resistance, and a coated abrasive tool used as a wear resistant tool.

[0002]

2. Description of the Related Art Conventionally, a hard film formed by a PVD method is TiN.
Was the mainstream, but recently, TiCN film or (TiA
l) New types of coatings such as N have been developed and attracted attention. TiCN has a Vickers hardness of nearly 3,000, and is much harder than Vickers hardness 2200 of TiN, and also has an effect of significantly increasing wear resistance. On the other hand, (TiA
l) N varies depending on the ratio of Ti to Al, but approximately 230
It has a Vickers hardness of 0 to 2800 and exhibits excellent characteristics under cutting conditions in which the cutting edge is at a high temperature because it has higher abrasion resistance and higher oxidation resistance than TiN.

In order to improve the film of the (TiAl) N film, Japanese Patent Publication No. Hei 5-67705, in which the ratio of Ti / Al is limited, and US Patents having a more multi-layer film such as (TiAlZr) N and (TiAlV) N No. 4871434 has been proposed and further improvements have been made. However, although these new coatings have the advantages described above, they are still not fully satisfactory in oxidation resistance.

[0004]

The reason that the oxidation resistance is insufficient is that the above-mentioned film containing Al certainly has an oxidation onset temperature of:
Although it is higher than TiN and TiCN and has excellent oxidation resistance, the oxidation progress rate is almost the same as that of TiN and TiCN under the condition where oxidation proceeds continuously. That is, the oxide film formed by oxidation is T
As in the case of iN and TiCN, the Al-containing coating is a porous coating having a rutile structure. Therefore, the resistance to the progress of oxidation is extremely low due to the rutile structure.

[0005]

The object of the present invention is to further improve the oxidation resistance of nitride and carbonitride coatings containing Ti and Al, and to provide a coating having a longer life in high-speed cutting where oxidation continues continuously. Is what you do.

[0006]

Therefore, in the present invention, as a result of studying the addition of various elements based on (TiAl) N, yttrium (hereinafter, referred to as Y) has been studied.
It was found that oxidation resistance was significantly improved by the addition of.
Table 1 shows the oxidation start temperature when Y was added when a 3 μm (TiAl) N film was formed by arc ion plating under the conditions of a bias voltage of 120 V and a nitrogen pressure of 10 ⁻¹ Pa, and 850 ° C. Oxidation rate in air is 3
The results are shown in comparison with a μm TiN, (Ti _0.5 Al _0.5 ) N film.

[0007]

[Table 1]

From Table 1, it can be seen that the addition of Y to the (TiAl) N film improves the oxidation resistance of the film. Therefore, in the present invention, a part of Ti of a hard coating having a thickness of 0.5 to 15 μm and composed of nitride, carbonitride, and carbide of Ti and Al and / or a solid solution thereof as a main component is represented by Y. in a molar ratio of said coating composition of substituted coated hard _{alloy, (Ti a Al b Y c} ) when expressed C _x N _1-x, a, a, b, c, x, respectively, a + b + C =
1, 0.3 ≦ a ≦ 0.7, 0.3 ≦ b ≦ 0.7, 0.0
A film composed of 01 ≦ c <0.01 and 0 ≦ x ≦ 1; a layer of (TiAlY) nitride, carbonitride, and carbide in which a part of the main component is substituted with Y; Nitride or carbonitride, or Ti nitride or carbonitride, or T
a layer of iAl solid solution nitride or carbonitride
It has a multi-layer structure or a multi-layer structure, which has high oxidation resistance and high hardness.

[0009]

When Y is added to a (TiAl) compound film, the oxidation resistance of the film can be improved. In particular, the reason why a remarkable improvement in the oxidation rate becomes possible is that Y
This is because the form of the formed oxide film shows an anatase structure instead of a rutile structure when is added. That is,
A very dense oxide film is formed by the addition of Y, and the progress of the oxidation is controlled by the diffusion of oxygen in the formed oxide film, whereby the progress of the oxidation is remarkably suppressed. Therefore, in high-speed cutting in which oxidation progresses continuously, oxidation of the film occurs only on the very surface, which acts as a protective film against oxidation, so that oxidation does not progress inside the film and a long life can be obtained. is there.

The reason for limiting the numerical values will be described below. If Y added as a solid solution / mixture to the (TiAl) compound film is less than 0.001, there is no sufficient effect to improve the oxidation resistance, and if it exceeds 0.01, the hardness of the film tends to decrease. Therefore, the abrasion resistance tends to slightly deteriorate, so that the range of 0.001 ≦ c <0.01 is set. still,
Similar effects can be obtained by forming the above-mentioned elements into a solid solution as a target material, adjusting the components at the time of vapor deposition using each element as an individual target, and further combining a solid-solution target and an individual target.

On the other hand, if the content of Ti exceeds 0.7, the content of Al decreases, and the oxidation resistance deteriorates. On the other hand, if it is less than 0.3, the hardness is significantly reduced. ≦ 0.
7 was set. The ratio of CN in the coating was 0 ≦ x ≦ 1, that is, the range of carbide, nitride and carbonitride was (Ti
Al) Oxidation resistance is improved by the effect of Y added as a solid solution / mixture in the film, so that carbides having lower oxidation resistance than nitrides can be used satisfactorily. The range of 0 ≦ x ≦ 1 was set because there is no extreme deterioration in wear resistance of carbonitrides. When the number of layers or the number of layers is not more than five, the size of the particles in each layer cannot be reduced and the hardness is not improved.

[0012]

Embodiment 1 Hereinafter, the present invention will be described in detail with reference to embodiments. 84WC-3TiC-1TiN-3TaC-9C
2. A commercially available 2.5 μm WC powder having a composition of
5 μm TiC powder, same TiN powder, 1.2 μm Ta
C powder was mixed in a ball mill for 96 hours, and after dry granulation, the TA insert of SNMG432 was pressed, sintered, and processed into a predetermined shape. PV on the cemented carbide substrate
Films as shown in Table 2 were formed by Method D using various (TiAlY) alloy targets. For comparison, the film described in the conventional example was also formed.

[0013]

[Table 2]

Next, the temperature of the throw-away insert coated with these films is gradually increased in the atmosphere,
The temperature at which increased oxidation was observed was measured. In addition, 90
At 0 ° C., the amount of increase in oxidation was measured over time, and the oxidation rate was calculated. These results are shown in Table 2.

Further, a cutting test was performed under the following high-speed cutting conditions, and a life time until the maximum wear reached 0.2 mm was determined. The results are shown in Table 3.

[0016]

[Table 3]

From Table 3, it is apparent that the film to which Y is added has a remarkably low oxidation rate, which contributes to a remarkably long life in continuous high-speed cutting.

[0018]

Example 2 Using the same cemented carbide indexable insert used in Example 1, the coating component system shown in Table 4 was multilayered and laminated. In this case, the total thickness of the coating was unified to 8 μm. Table 4 shows the results of the oxidation resistance test performed in the same manner as in Example 1. The hardness was measured by Ultra Micro Vickers (load: 10 g). The results are also shown in Table 4.

[0019]

[Table 4]

From Table 4, it is recognized that the hardness is improved by the multilayer or the lamination, and that the hardness is remarkably improved in the case of 1600 layers (5 nm per layer).

[0021]

The coated hard alloy of the present invention is made of a conventional Ti
By adding Y as compared with N and TiAlN, the oxidation resistance, especially the oxidation resistance speed, is improved, and a significantly longer tool life can be obtained. Although the present invention has mainly been described with respect to a cemented carbide, it is obvious that the present invention exhibits excellent effects when applied to a TiCN-based cermet and when applied to a high-speed steel.

Claims (2)

(57) [Claims] 1. A hard coating having a thickness of 0.5 to 15 μm and comprising a nitride, a carbonitride, and a carbide of Ti and Al and / or a solid solution thereof as a main component.
Part of the molar ratio of said coating composition coated hard alloy obtained by substituting _{yttrium, (Ti a Al b Y c} ) when expressed C _x N _1-x, a, a, b, c, x, respectively, a + b + C =
1, 0.3 ≦ a ≦ 0.7, 0.3 ≦ b ≦ 0.7, 0.0
A coated hard alloy, characterized in that it is a film comprising 01 ≦ c <0.01 and 0 ≦ x ≦ 1. 2. The coated hard alloy according to claim 1, wherein
A layer of a (TiAlY) nitride, carbonitride, or carbide in which a part of the main component is substituted with Y, and a nitride or carbonitride of Al, or a nitride or carbonitride of Ti, or Ti
A coated hard alloy characterized by comprising five or more layers or laminations of a nitride or carbonitride of a solid solution of Al.