JP2001287104A - COVERED cBN-CONTAINING SINTERED BODY CUTTING TOOL - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool excellent in abrasive resistance as compared with a conventional cBN-containing sintered body tool in cutting quenched steel of a high-hardness material. SOLUTION: A surface relating to the cutting of the cBN-containing sintered body containing 25-99 vol.% of cBN is covered with one or more layers containing aluminum oxynitride. Each of the aluminum oxynitride layers is formed of an Al-O-N solid solution, an Al-O-N compound or a mixture of both of them, and AIN may additionally be mixed to it. The thickness of one of the aluminum oxynitride layers is 0.5-10 μm, and is used as the first layer for tightly fitting the aluminum oxynitride layer to the cBN-containing sintered body even for a multi-layer film. The cBN-containing sintered body hardly causes plastic deformation under high temperature, and is suitable for the covering base material of the high-hardness material cutting tool. The tool having excellent abrasive resistance in machining the high-hardness material can be provided by covering it with the aluminum oxynitride layer having excellent adhesion to the cBN-containing sintered body and excellent abrasive resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool in which a cBN-containing sintered body is coated with an aluminum oxynitride layer,
The present invention relates to a cutting tool for a cBN-containing sintered body coated with an aluminum oxynitride layer, in which the adhesion strength between the cBN-containing sintered body and the coating layer is improved and the coating layer has high wear resistance.

[0002]

2. Description of the Related Art The use of cBN-containing sintered compact cutting tools has increased as a tool for machining high-hardness steel. In recent years, with the increase in processing speed, it has become necessary to improve the wear resistance of sintered tools containing cBN. As a solution to this, there is a hard film coating on the cBN-containing sintered body. Al ₂ O ₃ , TiN, (TiAl) N, etc. are known as hard film coatings on cBN-containing sintered bodies, but Al ₂ O ₃ has a weak bonding force with cBN-containing sintered bodies. There is. Further, TiN and (TiAl) N have insufficient wear resistance in machining hardened steel. Tools with aluminum oxynitride film coated on cemented carbide and ceramics are also known,
In hardened steel processing, the plastic deformation resistance of the base material is insufficient.

[0003]

SUMMARY OF THE INVENTION A on cBN-containing sintered body
Japanese Patent Application Laid-Open No. S59-8679 proposes an invention of l ₂ O ₃ film coating. However, if Al ₂ O ₃ is directly coated on a cBN-containing sintered body, sufficient adhesion strength cannot be obtained. Therefore, Japanese Patent Application Laid-Open
JP-A-227610 proposes to mix Al ₂ O ₃ as a binder for the cBN-containing sintered body, but by adding Al ₂ O ₃ as a binder, the physical properties of the cBN-containing sintered body, particularly the strength, Is reduced.

[0004] Also, Japanese Patent Application Laid-Open No. 10-086002,
Japanese Patent Application Laid-Open No. 05-043323 proposes coating of an aluminum oxynitride film on a cemented carbide and ceramics. In high-speed processing of steel, there is a problem that the base material is plastically deformed. The present invention solves the above problems and provides a tool having excellent wear resistance in cutting hardened steel.

[0005]

According to the present invention, cBN is contained in an amount of 25 to 9 by volume.
By coating a hard coating containing at least one aluminum oxynitride layer on a cBN-containing sintered body containing 9%, a cutting tool having both excellent adhesion and wear resistance was obtained. . aluminum nitride as a coating layer adjacent to the cBN content sintered body on the excellent adhesion to the cBN content sintered body as compared with Al ₂ O _3, oxidation resistance and comparable to Al ₂ O ₃ It is clear that it has abrasion, has higher thermal conductivity and thermal shock resistance than Al ₂ O ₃ , and has excellent cutting performance especially for cutting hardened steel.

[0006] Aluminum oxynitride is an aluminum oxide containing 1 atomic% or more of nitrogen in aluminum oxide from the viewpoint of wear resistance.
-ON solid solution or Al ₂₃ O ₂₇ N ₅ , Al ₂ O ₂ N, Al ₉ O ₃ N ₇ etc.
Limited to compounds represented by AlxOyNz. In some cases, by containing 50% or less of AlN, a coating having better thermal conductivity can be obtained, and the cutting heat generated at the cutting edge can be easily radiated quickly. If the thickness per aluminum oxynitride layer is less than 0.5 μm, the adhesion is sufficient, but the desired wear resistance cannot be obtained. If the thickness is more than 10 μm, the surface roughness and toughness of the coating increase. Since the decrease is remarkable, 1
The thickness per layer was limited to 0.5-10 μm. When the thickness of the coating layer is less than 0.5 μm, the desired wear resistance cannot be obtained. When the thickness is more than 50 μm, the coating stress increases and the entire tool becomes brittle, so that the thickness is limited to 0.5 to 50 μm.

In order to further improve abrasion resistance, a multi-layer structure is formed, and an aluminum oxynitride layer is coated adjacent to the surface of the cBN-containing sintered body to function as an underlayer which is firmly adhered to the outer layer film. Have. Aluminum oxynitride layer and cB
In the N-containing sintered body, the nitrogen atoms contained in the aluminum oxynitride layer are covalently bonded to the cBN abrasive grains, which are the components contained in the cBN-containing sintered body, and the nitride of the metal in the binder. Because it acts as a nucleation factor during film formation,
The aluminum oxynitride layer and the cBN-containing sintered body adhere to each other,
It was clarified that the inclusion of at least one of AlN and Al-ON in the sintered body further firmly adhered.

The coating can be applied to a wide cutting area by forming a multilayer, and specifically, Al ₂ O ₃ , TiCN, TiB ₂ , AlN, Ti
C, TiN, TiCNO, (Ti, Al) N, (Ti, Al) CN, (Ti, Al)
At least one or two or more CNOs are coated. When wear resistance is required in a higher speed region, Al ₂ O ₃ is desirable.If the thickness is less than 0.1 μm, the desired wear resistance and oxidation resistance cannot be obtained, and if the thickness is greater than 40 μm, the entire coating becomes brittle. Therefore, it was set to 0.1 to 40 μm. Hereinafter, examples of the present invention will be described.

[0009]

[Example 1] The cBN content was 65% by volume and the balance was TiN.
Raw material 6GPa is Al, the sintered cBN containing sintered body used as a covering matrix at 1773K, by a thermal CVD method, Al ₂ O
_Three films and an AlxOyNz film were prepared and evaluated by a cutting test. As the work material, SKD11 of HRc60 was used, and a dry turning test including partly interrupted was performed. Table 1 shows the film forming conditions for each film.

[0010]

[Table 1] Deposition gas conditions for various coatings The unit is volume%

The film formation temperature is 1273 K, and the film thickness is 3 μm.
The film forming time was adjusted so that The obtained coating was analyzed by Auger spectroscopy and X-ray diffraction analysis, and AlxOy
The Nz film (1) is Al ₂ O ₃ (N) containing 2 atomic% of N, and AlxOy
The Nz film (2) is Al ₂₃ O ₂₇ N ₅ containing 9 atomic% of N, and AlxO
The yNz film (3) is composed of Al ₉ O ₃ N ₇ containing 28 atomic% of N and Al ₂
Identified as a mixture of O ₂ N. A cutting test was performed on the tool before coating as a comparison with the obtained hard film-coated tool.
Table 2 shows the results.

[0012]

[Table 2] Cutting conditions: V = 180 m / min, d = 0.15 mm, f = 0.
07mm, cutting time 20min

From the results shown in Table 2, the aluminum oxynitride layers (particularly, AlxOyNz films (1) and AlxOyNz films (2)) have better adhesion to the cBN-containing sintered body of the base material than the Al ₂ O ₃ film. Excellent,
Abrasion resistance can be greatly improved compared to uncoated products.

[0014]

Example 2 The cBN content was 65% by volume and the balance was TiN.
CBN-containing sintering sintered Al material at 6GPa, 1773K
Using the binder as a coating base material, thermal CVD_TwoO
_ThreeFilm, Al _TwoO_ThreeAl-O-N solid solution film between film and cBN-containing sintered body
Evaluated by comparative cutting test with that coated as an intermediate layer
Was done. Work material uses SKD11 of HRc60, and partly intermittent
A dry turning test was carried out. The film formation conditions are based on Table 1.
However, to make the thickness of the entire film the same,_TwoO_ThreeThe membrane is 3μ
m, AlxOyNz film (2) + Al_TwoO_ThreeFilm: AlxOyNz film
(2): 0.5 μm, Al_TwoO_ThreeFilm: 2.5 μm. Profit
Tool before coating as a comparison with
A cutting test was performed. Table 3 shows the results.

[0015]

[Table 3] Cutting conditions: V = 180 m / min, d = 0.15 mm, f = 0.
07mm, cutting time 20min

From the results shown in Table 3, the aluminum oxynitride layer is
It can be seen that it works effectively also as an adhesion intermediate layer between the cBN-containing sintered body and the Al ₂ O ₃ film.

[0017]

Embodiment 3 A raw material having a cBN content of 65% by volume, AlN 2%, and the balance TiN and Al, and Al ₂ O ₂ N 5%, the balance being TiN and Al
A cBN-containing sintered body obtained by sintering the raw material at 6 GPa and 1773 K is used as a coating base material, and Al ₂ O ₃
A film, an AlxOyNz film (2) and an AlxOyNz were prepared and evaluated by a cutting test. The work material uses SKD11 of HRc60,
Dry turning tests including some intermittent operations were performed. The deposition temperature is 1
At 273K, the film formation time was adjusted so that the film thickness was 3 μm. A cutting test was performed on the tool before coating as a comparison with the obtained hard film-coated tool. Table 4 shows the results.

[0018]

[Table 4] Processing conditions: V = 180 m / min, d = 0.15 mm, f = 0.
07mm, processing time 20min

Although the binder of the cBN-containing sintered body contains AlN or Al ₂ O ₂ N, the abrasion resistance of the cBN-containing sintered body itself seems to be somewhat impaired. The abrasion resistance is further improved when the AlxOyNz film (2) is coated. As a secondary effect, the adhesion between the Al ₂ O ₃ film and the cBN-containing sintered body is also improved.

[0020]

Example 4 The cBN content was 65% by volume and the balance was TiN.
A cBN-containing sintered body obtained by sintering a raw material of Al at 6 GPa and 1773 K is used as a coating base material, and is subjected to a thermal CVD method to obtain a 0.1 g / m 2.
A 5 μm AlxOyNz film (2) is formed, and a 2.5 μm
The substrate coated with the Al2O3
iN coated at 1 μm and 0.5 μm between Al ₂ O ₃ film and TiN
A sample coated with a μm AlxOyNz film (2) was evaluated by a cutting test. As the work material, SKD11 of HRc60 was used, and a dry turning test including partly interrupted was performed. Table 5 shows the results.

[0021]

[Table 5] Processing conditions: V = 180 m / min, d = 0.15 mm, f = 0.
07mm, processing time 20min

As shown in Table 5, the aluminum oxynitride layer is also effective for improving the adhesion between the Al ₂ O ₃ film and the TiN film.

[0023]

Embodiment 5 The tests up to Example 4 are tests using a CVD apparatus, but in Example 5, an Al-ON film was coated on a cBN-containing sintered body by a PVD apparatus. The equipment uses unbalanced magnetron sputter-link type PVD, and Al ₂ O ₃
When a film was formed for 3 hours in a target atmosphere of 0.1 Torr of argon / nitrogen, 4 g of a film were formed on the cBN-containing sintered body.
A μm Al-ON film was coated. The coated Al-ON film is Al ₂₃
Al ₂ O ₃ containing 5 atomic% of γALON having a chemical formula of O ₂₇ N.

[0024]

By coating an aluminum oxynitride layer on a cBN-containing sintered body, a hard-film-coated cBN-containing sintered body tool in which the base material and the coating layer are firmly adhered to each other can be obtained. Excellent tool life was obtained by machining. By coating the aluminum oxynitride layer as an intermediate layer between the cBN-containing sintered body and the upper coating layer, the upper coating layer, cBN
The peeling resistance between the contained sintered bodies can be greatly improved,
Excellent tool life was obtained by machining hardened steel.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C22C 29/04 C22C 29/04 29/10 29/10 29/12 29/12 29/14 29/14 Z 29/16 29/16 GH C23C 8/24 C23C 8/24 (72) Inventor Haruhiko Kiyo 580 Horikawa-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Solid Square Toshiba Tungaloy Co., Ltd. F-term (reference) 3C046 FF02 FF10 FF13 FF16 FF25 FF35 HH06 4K018 AD15 BA08 BA11 DA11 FA24 KA15 4K028 AA02 AB04

Claims (8)

[Claims] A cBN-containing sintered body containing 25 to 99% by volume of cBN is coated with a single layer or a multilayer film having two or more layers having a total thickness of 1 to 50 μm, and at least one layer has a thickness of 0.5 to 10 μm CBN characterized by being an aluminum oxynitride layer
Containing sintered body cutting tool 2. The aluminum oxynitride layer according to claim 1, wherein the solid solution of N is 1 atomic% or more in an Al-ON solid solution or AlxOyNz.
The coated cBN-containing sintered body cutting tool according to claim 1, wherein the cutting tool is an Al-NO compound or a mixture of both. 3. 50% by volume of the solid solution, compound and mixture.
The coated cBN-containing sintered compact cutting tool according to claim 1, comprising the following AlN. 4. The method according to claim 1, wherein the aluminum oxynitride layer is coated adjacently on the cBN-containing sintered body.
Cutting tool for coated sintered body containing coated cBN according to item 2 or 3. 5. The coated cBN according to claim 1, wherein said cBN-containing sintered body contains at least one of AlN and Al-ON in an amount of 0.1 to 30% by volume. Containing sintered body cutting tool 6. An aluminum oxynitride layer between the cBN-containing sintered body and the Al ₂ O ₃ film, wherein the outermost layer comprises an Al ₂ O ₃ film having a thickness of 0.1 to 40 μm. 1, 2, 3,
4. A cutting tool for a sintered body containing coated cBN according to any one of items 4 and 5. 7. In the multilayer film, the film other than the aluminum oxynitride layer is made of Al ₂ O ₃ , TiCN, TiB ₂ , AlN, TiC, TiN, TiCNO, (T
The coating according to any one of claims 1, 2, 3, 4, 5, and 6, comprising (i, Al) N, (Ti, Al) CN, and (Ti, Al) CNO.
cBN-containing sintered cutting tool 8. An aluminum oxynitride layer and Al ₂ O ₃ , TiCN, TiB ₂ , AlN, TiC, TiN, TiCNO, (Ti, A
1) Claims 1, 2, 3, 4, wherein at least one of N, (Ti, Al) CN, and (Ti, Al) CNO are alternately laminated.
The coated cBN-containing sintered body cutting tool according to any one of claims 5, 6, and 7.