JPH10204639A - Cutting tool made of surface-coated cemented carbide in which hard coating layer has excellent chipping resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool made of surface-coated cemented carbide in which a hard coating layer shows excellent chipping resistance over a long period. SOLUTION: This cutting tool made of surface-coated cemented carbide is composed by chemically and/or physically vapor-depositing on the surface of a WC base cemented carbide substrate, a hard coating layer contg. α type Al2 O3 layers, e.g. a hard coating layer composed of at least one or >= two kinds among Ti compound layers composed of a TiC layer, a TiN layer, a TiCN layer, a TiO2 layer, a TiCO layer, a TiNO layer and a TiCNO layer and α type Al2 O3 layers with the average layer thickness of 2 to 20μm. In this case, the αtype Al2 O3 layers composing the hard coating layer are composed of two or more α type Al2 O3 unit layers showing different X-ray diffraction patterns. Furthermore, the α type Al2 O3 unit layers are composed of α type Al2 O3 composite layers showing X-ray diffraction patterns in which the most intensive peak appears in any of 25.5 degrees at 2θ, 35.5 degrees at 2θ, 37.2 degrees at 2θ and 68.4 degrees at 2θ, and the ratio of the most intensive peak height (H1 ) to the secondary peak height (H2 ) in the same X-ray diffraction pattern, i.e., (H1 )/(H2 ) is regulated to 1.5 to 2.7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a hard coating layer having excellent chipping resistance, and is therefore applicable to severe conditions such as high-speed cutting of steel and cast iron and heavy cutting such as high feed and high cutting. The present invention relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated cemented carbide tool) that exhibits excellent cutting performance over a long period of time without chipping (small chipping) of the cutting edge.

[0002]

2. Description of the Related Art Conventionally, generally, a hard coating layer including an α-type aluminum oxide (hereinafter, referred to as Al ₂ O ₃ ) layer is formed on a surface of a tungsten carbide-based cemented carbide substrate (hereinafter, referred to as a cemented carbide substrate). Ti carbide (hereinafter referred to as TiC)
Layer, nitride (hereinafter also indicated as TiN) layer, carbonitride (hereinafter indicated as TiCN) layer, oxide (hereinafter referred to as TiO ₂₎
), A carbon oxide (hereinafter referred to as TiCO) layer, a nitrogen oxide (hereinafter referred to as TiNO) layer, and a Ti compound layer including a carbon oxynitride (hereinafter referred to as TiCNO) layer. Coated carbide tools are known which are obtained by chemical vapor deposition and / or physical vapor deposition of a hard coating layer composed of one or more kinds and an Al ₂ O ₃ layer with an average layer thickness of 2 to 20 μm. It is also known that this coated carbide tool is used for continuous cutting or interrupted cutting of steel, cast iron, or the like.

[0003]

On the other hand, in recent years, high performance and high output of a cutting device have been remarkable, and there is a strong demand for labor saving. Accordingly, cutting has been performed at a high speed and a high feed rate and a high depth of cut have been required. However, in the above-mentioned conventional coated carbide tools, the Al ₂ O ₃ layer among the hard coating layers constituting the same is particularly excellent in oxidation resistance and thermal stability, and has a higher hardness. Although it has hardness, its strength is relatively low as compared to the Ti compound layer, which is another constituent layer, and it is brittle.For example, in severe conditions such as high-speed cutting or heavy cutting of steel or cast iron. In cutting, chipping easily occurs on the cutting edge, and as a result, the service life of the cutting blade is relatively short and the service life is short.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the viewpoint as described above, the hard coating layer of the coated carbide tool is formed.
Al formed_Two O_Three Focusing on the layer, its strength and toughness
As a result of conducting research to improve
Al constituting hard coating layer of coated carbide tool_Two O_ThreeThe layers are
When a chemical vapor deposition apparatus is used, for example, (A) reaction gas composition_Three : 1-3%, CO_Two : 1.5 ~
4.5%, HCl: 3-9%, H_Two S: 1-2%, H
_Two (B) reaction temperature: 900 to 1100 ° C .; (C) reaction pressure: 25 to 100 torr._Two O_Three layer
Prior to the formation of, the (a) reaction gas composition in volume%_Three : 20-25%, CO_Two : 35 ~
37.5%, H_Two : Remaining, (b) reaction temperature: 1000 to 1200 ° C., (c) reaction pressure: 0.01 to 1 torr, (d) time: 10 to 60 minutes. Before formation
The surface of the super-hard substrate after the treatment is treated under the above conditions (A) to (C).
Al of specified thickness_Two O_Three When a layer is formed, the above (a) to
Formed without pretreatment for crystal nucleus formation under condition (d)
Conventional Al_Two O _Three In the layer, the X-ray diffraction illustrated in FIG.
What showed the pattern, the crystal nucleation pretreatment strip
By adjusting the matter, examples are shown in Figs.
25.5 degrees, 35.5 degrees, and 37.degree.
The strongest peak appears at either 2 degrees or 68.4 degrees
The strongest peak height (H₁X-ray diffraction pattern
The second peak height (H_Two) Ratio (H₁) /
(H_Two) Shows an X-ray diffraction pattern of 1.5 to 2.7.
And this is A_Two O_Three Unit layer and different X
A of two or more layers showing a line diffraction pattern_Two O_Three At the unit layer
A_Two O_Three When the layers are constructed, the resulting A_Two O_Three Composite layer
Is the conventional Al_Two O_Three High strength and high toughness compared to layers
The hard coating layer has excellent resistance to
Comes to have a papping property, and therefore coated carbide
The tool is used for severe cutting such as high-speed cutting and heavy cutting of steel and cast iron.
No chipping on the cutting edge for cutting
That cutting performance will be exhibited over a long period of time.
The result was obtained.

[0005] Note that, X-rays diffraction pattern shown in Figure 1, in a normal chemical vapor deposition apparatus, the surface of the carbide substrate A to be described later, with (a) the reaction gas composition _{volume%, AlCl 3: 22%,} CO ₂ : 37%, H
₂ : Remaining, (b) reaction temperature: 1150 ° C., (c) reaction pressure: 0.1 torr, (d) time: 40 minutes, pretreatment for crystal nucleation was performed. On the surface of the cemented carbide substrate, under normal conditions, that is, (A) reaction gas composition volume%, AlCl ₃ : 2%, CO ₂ : 8%, HCl:
3%, H ₂ S: 3%, H ₂ : residual, (B) reaction temperature: 1000 ° C., (C) reaction pressure: 50 torr, (D) time: 300 minutes (the average layer thickness in Examples is adjusted by time) ), The average layer thickness formed under the following conditions: 5 μm Al ₂ O ₃ layer (In the following examples, the Al ₂ O ₃ layer formed under the above conditions was A
In l ₂ O ₃ referred to as the unit layer A), H ₁ is 2 [Theta]: appears to 25.5 degrees, H ₁ / H _2: shows a 1.6.

The X-ray diffraction pattern shown in FIG. 2 also shows that (a) the reaction gas composition volume%, AlCl ₃ : 20%, CO ₂ : 35%, H
₂ : remaining, (b) reaction temperature: 1050 ° C., (c) reaction pressure: 0.05 torr, (d) time: 10 minutes, pretreatment for crystal nucleus formation was performed. On the surface of the cemented carbide substrate, under ordinary conditions, that is, (A) reaction gas composition volume%, AlCl ₃ : 2%, CO ₂ : 10%, HC
1: 5%, H ₂ S: 2%, H ₂ : residual, (B) reaction temperature: 1020 ° C., (C) reaction pressure: 50 torr, (D) time: 280 minutes (average layer thickness in Examples is time The average layer thickness formed under the following conditions: 5 μm Al ₂ O ₃ layer (In the following examples, the Al ₂ O ₃ layer formed under the above conditions was A
In l ₂ O ₃ referred to as the unit layer b), H ₁ is 2 [Theta]: appears to 35.5 degrees, H ₁ / H _2: shows a 2.7.

The X-ray diffraction pattern shown in FIG. 3 shows that (a) the reaction gas composition volume%, AlCl ₃ : 22%, CO ₂ : 37%, H
₂ : Remaining, (b) Reaction temperature: 1100 ° C., (c) Reaction pressure: 0.01 torr, (d) Time: 50 minutes, pretreatment for crystal nucleation was performed. On the surface of the cemented carbide substrate, under normal conditions, that is, (A) reaction gas composition volume%, AlCl ₃ : 2%, CO ₂ : 8%, HCl:
5%, H ₂ S: 2%, H ₂ : residual, (B) reaction temperature: 960 ° C., (C) reaction pressure: 50 torr, (D) time: 340 minutes (the average layer thickness in Examples is adjusted by time) ), The average layer thickness formed under the following conditions: 5 μm Al ₂ O ₃ layer (In the following examples, the Al ₂ O ₃ layer formed under the above conditions was A
In l ₂ O ₃ referred to as the unit layer c), H ₁ is 2 [Theta]: 37.2 [deg appeared, H ₁ / H _2: is of showing a 2.4.

Further, the X-ray diffraction pattern shown in FIG.
Similarly, on the surface of the cemented carbide substrate A, (a) 25% of AlCl ₃ , 37.5% of CO ₂ ,
H ₂ : remaining, (b) reaction temperature: 1200 ° C., (c) reaction pressure: 0.1 torr, (d) time: 30 minutes, pretreatment for forming crystal nuclei, and after this pretreatment for forming crystal nuclei. On the surface of the cemented carbide substrate, the following conditions were used: (A) reaction gas composition volume%, AlCl ₃ : 2%, CO ₂ : 10%, HC
1: 2%, H ₂ S: 1%, H ₂ : residual, (B) reaction temperature: 960 ° C., (C) reaction pressure: 50 torr, (D) time: 330 minutes (average layer thickness in Examples is time The average layer thickness formed under the following conditions: 5 μm Al ₂ O ₃ layer (In the following examples, the Al ₂ O ₃ layer formed under the above conditions was A
In l ₂ O ₃ referred to as the unit layer d), H ₁ is 2 [Theta]: 68.4 [deg appeared, H ₁ / H _2: is intended to indicate a 2.1.

The X-ray diffraction pattern shown in FIG. 5 shows that the surface of the superhard substrate A is also formed under normal conditions, that is, (A) the reaction gas composition volume%, AlCl ₃ : 2%, CO ₂ : 10 %, HC
1: 5%, H ₂ S: 1%, H ₂ : residual, (B) reaction temperature: 1020 ° C., (C) reaction pressure: 50 torr, (D) time: minute (the average layer thickness in Examples is time Adjustment) The average thickness of the conventional Al ₂ O ₃ layer formed under the following conditions: 5 μm (in the following examples, the Al ₂ O ₃ layer formed under the above conditions is referred to as an Al ₂ O ₃ single layer). Things.

The present invention has been made on the basis of the above research results, and includes a hard coating layer including an Al ₂ O ₃ layer, for example, a TiC layer, a TiN layer, a TiC layer
N layer, TiO ₂ layer, TiCO layer, TiNO layer, and T layer
One or two of Ti compound layers made of iCNO layer
And a hard coating layer composed of an Al ₂ O ₃ layer
In the coated cemented carbide tool formed with an average layer thickness of ２０20 μm, the Al ₂ O ₃ layer constituting the hard coating layer is formed from two or more Al ₂ O ₃ unit layers showing different X-ray diffraction patterns. And the Al ₂ O ₃ unit layer is 2 at 2θ.
5.5 degrees, 35.5 degrees, 37.2 degrees, and 68.degree.
The strongest peak appears at any one of the four degrees, and the ratio (H ₁ ) / (H ₂ ) of the second peak height (H ₂ ) in the same X-ray diffraction pattern as the strongest peak height (H ₁ ) is 1 .5-
The present invention is characterized by a coated carbide tool having a hard coating layer having excellent chipping resistance, which is composed of an Al ₂ O ₃ composite layer exhibiting an X-ray diffraction pattern of 2.7.

In the coated carbide tool according to the present invention,
Al in the hard coating layer_Two O_Three Al constituting the composite layer_Two 
O_Three Strongest peak height in X-ray diffraction pattern of unit layer
(H ₁) And the second peak height (H_Two) Ratio (H₁) /
(H_Two): 1.5 to 2.7 are empirically determined.
Thus, an X-ray diffraction pattern whose ratio is less than 1.5 is shown.
Al_Two O_Three Unit layer is Al_Two O_Three Fields that existed in the composite layer
The desired high strength and high toughness can be secured
As a result, the hard coating layer has the desired effect of improving chipping resistance.
No effect, while increasing the ratio above 2.7
Is extremely difficult,
In this case, the ratio is desirably 2.0 to 2.5,
In addition, the average layer thickness of the hard coating layer was set to 2 to 20 μm.
Has a desired excellent wear resistance when its layer thickness is less than 2 μm.
Cannot be secured, while the layer thickness exceeds 20 μm.
, The fracture resistance will decrease.
Preferably, the average layer thickness is 3 to 10 μm.
Good.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide tool of the present invention will be specifically described with reference to examples. As raw material powders, average WC powder having an average particle diameter of 3 μm, coarse WC powder having an average particle diameter of 5 μm, and (Ti, W) C having an average particle diameter of 1.5 μm (the same in weight ratio, hereinafter, TiC / WC = 30/70) 1.2 μm (Ti, W) CN (weight ratio, same hereafter, TiC / Ti)
N / WC = 24/20/56) powder, 1.3 μm (Ta, Nb) C (TaC / NbC = 90/10) powder and 1.2 μm Co powder were prepared. After blending into the blending composition shown in Table 1, wet-mixing with a ball mill for 72 hours, and drying, ISO / CNMG
120408 (for carbide substrates A to D) and SEEN4
Pressed into a green compact having a shape defined by 2AFTN1 (for the superhard substrate E), and the green compact was vacuum-sintered under the conditions shown in Table 1 to produce the superhard substrates A to E, respectively. Further, 100 to
After holding at 1400 ° C. for 1 hour in an rr CH ₄ gas atmosphere, a slow cooling carburizing treatment is performed, and after the treatment, carbon and Co adhering to the substrate surface are removed by acid and barrel polishing to obtain a depth from the surface. : Maximum Co content at a position of 10 μm:
A Co-enriched zone of 15% by weight and a depth of 40 μm was formed on the surface of the substrate. In addition, the cemented carbide substrates A and D have a maximum C at a depth of 15 μm from the surface while being sintered.
o Co-enriched zone having a content of 9% by weight and a depth of 20 μm is formed on the surface portion, and the remaining cemented carbide substrates C and E do not have the Co-enriched zone. Had a homogeneous structure. Table 1 shows the internal hardness (Rockwell hardness A scale) of each of the superhard substrates A to E.
Are shown respectively.

Next, the surfaces of these super hard substrates A to E
Then, with the honing applied, a normal chemical vapor deposition
The conditions shown in Table 2 and the above Al_TwoO_Threelayer
Under the forming conditions, the composition and average layer thickness shown in Tables 3 and 4
Ti layer and Al_TwoO _ThreeBy forming a layer
Coated carbide tools 1 to 12 of the present invention and conventional coated carbide tools
1 to 9 were each manufactured.

Next, the coated carbide tools 1 to 11 according to the present invention will be described.
Work material: round bar of SCM440, cutting speed: 300 m / min. Infeed: 5 mm Feed: 0.2 mm / rev. , Cutting time: 10 minutes, Dry continuous high speed high depth cutting test of alloy steel under the following conditions: Work material: Square bar of SCM439, Cutting speed: 100 m / min. Notch: 2.5 mm. Feed: 0.2 mm / rev. , Cutting time: 5 minutes, dry intermittent high depth cutting test of alloy steel under the conditions of
Further, regarding the above-mentioned coated carbide tool 12 of the present invention and the conventionally coated carbide tool 9, a work material: a square material of FC25, a cutting speed: 100 m / min. Infeed: 3 mm. , Feed: 0.3 mm / tooth, cutting time: 40 minutes, a dry high-cut milling test of cast iron was performed under the following conditions, and the flank wear width of the cutting blade was measured in each of the cutting tests. Table 5 shows the results of these measurements.

[0015]

[Table 1]

[0016]

[Table 2]

[0017]

[Table 3]

[0018]

[Table 4]

[0019]

[Table 5]

[0020]

According to the results shown in Tables 3 to 5, the hard coating
Al in the layer_TwoO_ThreeAl layer with multiple layers _TwoO_ThreeComposed of unit layers
Al formed_TwoO_ThreeThe coated carbide tool of the present invention comprising a composite layer
1 to 12 are all Al_TwoO_ThreeA single-tier slave
Compared to conventional coated carbide tools 1-9_TwoO_ThreeComposite layer
Is the Al_TwoO_ThreeHigh strength and high toughness compared to single layer
The high cast iron and steel conditions
Excellent cutting performance without chipping on the cutting edge even in feed cutting
While cutting performance is exhibited over a long period of time,
In the hard tools 1 to 9, the Al_TwoO_ThreeDue to single layer
The occurrence of chipping on the cutting blade is inevitable.
It is clear that the service life can be reached in a relatively short time due to
is there. As described above, the coated carbide tool of the present invention
Of the hard coating layer constituting_TwoO_ThreeLayers were different
Two or more layers of Al showing an X-ray diffraction pattern_Two O_Three Unit layer
Al_TwoO_ThreeComposed of composite layers, which allows immediate
Steel and cast iron
Continuous cutting and intermittent cutting under normal conditions such as
And severe cutting such as high speed cutting, high feed and high depth of cut
Chipping on the cutting edge even when used for cutting under conditions
With excellent cutting performance over a long period of time
Yes, and therefore for higher performance and higher output of cutting equipment
It can respond sufficiently and contribute to labor saving.

[Brief description of the drawings]

[1] Al ₂ O ₃ units layer A of X-ray diffraction pattern (H ₁
/ H ₂ : 1.6).

[Figure 2] Al ₂ O ₃ units Soi of X-ray diffraction pattern (H ₁
/ H ₂ : 2.7).

[3] Al ₂ O ₃ units Sou of X-ray diffraction pattern (H ₁
/ H ₂ : 2.4).

[4] Al ₂ O ₃ units layer d of X-ray diffraction pattern (H ₁
/ H ₂ : 2.1).

FIG. 5 is a diagram showing an X-ray diffraction pattern of a conventional Al ₂ O ₃ single layer.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuki Hamaguchi 1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Pref. Mitsubishi Materials Corporation Tsukuba Works

Claims (2)

[Claims] 1. The surface of a tungsten carbide-based cemented carbide substrate
A hard coating layer containing an α-type aluminum oxide layer
Chemical vapor deposition and / or physical vapor deposition with an average layer thickness of 0 μm
In a cutting tool made of a surface-coated cemented carbide, comprising:
Two or more layers of α-type oxides showing different X-ray diffraction patterns
Aluminium oxide layer, and
25.5 degrees, 35.5 degrees, and 3 degrees in 2θ
The strongest peak at either 7.2 degrees or 68.4 degrees
Appears, the strongest peak height (H₁X-ray diffraction pattern
The second peak height (H_Two) Ratio
(H₁) / (H _Two) Is 1.5 to 2.7.
Turned α-type aluminum oxide composite layer
The hard coating layer characterized by excellent chipping resistance
Surface coated cemented carbide cutting tool. 2. The surface of a tungsten carbide-based cemented carbide substrate
, Ti carbide layer, nitride layer, carbonitride layer, oxide
Layers, carbonate layers, nitroxide layers, and carbonitride layers
Or two or more of the Ti compound layers
Hard coating layer composed of aluminum oxide layer and 2-2
Chemical vapor deposition and / or physical vapor deposition with an average layer thickness of 0 μm
In a cutting tool made of a surface-coated cemented carbide, comprising:
Two or more layers of α-type oxides showing different X-ray diffraction patterns
Aluminium oxide layer, and
25.5 degrees, 35.5 degrees, and 3 degrees in 2θ
The strongest peak at either 7.2 degrees or 68.4 degrees
Appears, the strongest peak height (H₁X-ray diffraction pattern
The second peak height (H_Two) Ratio
(H₁) / (H _Two) Is 1.5 to 2.7.
Turned α-type aluminum oxide composite layer
The hard coating layer characterized by excellent chipping resistance
Surface coated cemented carbide cutting tool.