JPH1076406A - Surface coated cemented carbide cutting tool with excellent chipping resistance with hard coating layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool made of a surface-coated cemented carbide in which a hard coating layer has excellent chipping resistance. SOLUTION: Al ₂ O is formed on the surface of a WC-based cemented carbide substrate.
Hard coating layers including _three layers, such as TiC layer, TiN layer, T
One or more of Ti compound layers including an iCN layer, a TiO ₂ layer, a TiCO layer, a TiNO layer, and a TiCNO layer, and a hard coating layer composed of an Al ₂ O ₃ layer
In a surface-coated cemented carbide cutting tool formed by chemical vapor deposition and / or physical vapor deposition with an average layer thickness of ２０20 μm, the Al ₂ O ₃ layer constituting the hard coating layer is formed of an α-type mainly composed of Al ₂ O _3. It has a crystal structure, and has different crystal structures in an upper part and a lower part (substrate side), and the upper part is a columnar Al ₂
An O ₃ layer, that is, a crystal structure in which columnar crystal grains are arranged in parallel in the vertical direction, and the lower side is formed of a granular Al ₂ O ₃ layer, that is, an Al ₂ O ₃ layer having a granular crystal structure.

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, therefore, to a severe cutting such as high-speed cutting of steel or cast iron and heavy cutting such as high-speed and high feed and high cutting. Surface coated cemented carbide cutting tool (hereinafter referred to as coated cemented carbide tool) that exhibits excellent cutting performance over a long period of time without chipping (small chipping) of the cutting edge even when used under various conditions Things.

[0002]

2. Description of the Related Art Conventionally, in general, a hard coating layer including an aluminum oxide (hereinafter, referred to as Al ₂ O ₃ ) layer, for example, Ti, is formed on a surface of a tungsten carbide-based cemented carbide substrate (hereinafter, referred to as a cemented carbide substrate). Carbide (hereinafter, referred to as TiC) layer, nitride (hereinafter, also referred to as TiN) layer, carbonitride (hereinafter, referred to as TiCN) layer, oxide (hereinafter, referred to as TiO ₂ ) layer, carbonate (hereinafter, referred to) , TiCO) layer, a nitrided oxide (hereinafter referred to as TiNO) layer, and one or more Ti compound layers including a carbonitride (hereinafter referred to as TiCNO) layer, and Al ₂ A coated carbide tool is known which is obtained by chemically and / or physically depositing a hard coating layer composed of an O ₃ layer and an average layer thickness of 2 to 20 μm. It is used for continuous and intermittent cutting such as It is also known that. Further, it is also known that the Al ₂ O ₃ layer constituting the hard coating layer has a crystal structure mainly composed of α-type or κ-type, or a mixture of α-type and κ-type, and has a granular crystal structure. .

[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, it is relatively low in strength compared to the other constituent layer Ti compound layer, and because it is brittle, for example, under severe conditions such as high-speed cutting and high-speed high-feed cutting of steel and cast iron In the above cutting, chipping easily occurs on the cutting edge, and as a result, the service life can be reached in a relatively short time at present.

[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
Mainly α-type crystal structure that forms the hard coating layer of coated carbide tools
And having a granular crystal structure_Two O_Three Layers (hereinafter,
Granular Al_Two O_Three(A) a reaction gas composition in volume%,_Three : 1-20%, CO_Two : 0.5 ~
30%, optionally HCl: 1-20% and / or H
_Two S: 0.05-5%, H_Two : Remaining, (b) reaction temperature: 950 to 1050 ° C., (c) reaction pressure: 30 to 200 torr._Two O
_Three When forming a layer, it is already formed on the way
Granular Al_Two O_Three The surface of the layer is prepared as follows: (a) HCl: 1-20%, H_Two (B) Reaction temperature: 1000-1100 ° C., (c) Reaction pressure: 30-200 torr._Two O_Three Cl on the surface of the layer
Adsorbed, and in this state, A_Two O_Three Layer formation
Is performed, the resulting Al_Two O_Three The layer is Al_Two 
O_Three Of course has an α-type crystal structure
Is different from the granular crystal structure constituting the lower part (substrate side).
The crystal grains grow in the vertical direction by the catalytic action of Cl,
And the columnar crystal grains are arranged in parallel.
Bottom, columnar Al_TwoO_Three Layer))
Columnar Al_Two O_Three The layer is the granular Al_Two O _Three High compared to layers
Because of its strength and high toughness, the upper part is columnar Al_Two 
O_Three Layer, the lower side is granular Al_Two O_Three Al composed of layers
_Two O_Three Hard coating layer with excellent resistance to chipping
In this case, the conventional coated carbide tool
Granular Al constituting hard coating layer_Two O_Three The layers are usually 1 to 1
It is formed with an average layer thickness of 0 μm.
Of 50 to 90%, that is, 0.5 to 9 μm_Two 
O_Three Layer and therefore this hard coating layer
Coated carbide tools made of steel are used for high-speed cutting of steel, cast iron, etc.
Suitable for cutting under severe conditions such as cutting and high-speed heavy cutting.
No cutting and excellent cutting performance over a long period of time
The research results show that they will be able to demonstrate their potential.

The present invention has been made based on the results of the above-mentioned research, and comprises 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 about 20 μm, the Al ₂ O ₃ layer constituting the hard coating layer is formed of Al
The main component of ₂ O ₃ has an α-type crystal structure, and has different crystal structures in the upper part and the lower part (substrate side), and the upper part has a columnar Al ₂ O ₃ layer, that is, Crystal structure arranged side by side in the direction, the lower part is a granular Al ₂ O ₃ layer,
That is, 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 layer having a granular crystal structure.

[0006] In the coated carbide tool of the present invention,
The average layer thickness of the columnar Al ₂ O ₃ layer constituting the upper part of the Al ₂ O ₃ layer in the hard coating layer is 0.5 to 9 μm as described above.
m, which has a layer thickness of 0.5 μm
If the thickness is less than 10 μm, the desired excellent chipping resistance cannot be ensured. On the other hand, if the layer thickness exceeds 9 μm, the crystal grains tend to be grained, and the reduction in chipping resistance is inevitable. In addition, the reason why the average layer thickness of the hard coating layer is set to 2 to 20 μm is that if the layer thickness is less than 2 μm, a desired excellent wear resistance cannot be secured, while the layer thickness is 20 μm This is because, if it exceeds, the fracture resistance is reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide tool of the present invention will be specifically described with reference to examples. As the raw material powder, an average particle size: fine WC powder of 1.5 μm, coarse WC powder of 5 μm, (Ti, W) CN of 1.2 μm (the same in weight ratio, hereinafter TiC / TiN / WC = 24/20/5
6) Powder (1.3 μm) of (Ta, Nb) C (TaC /
NbC = 90/10) powder, the same 1 μm Cr powder, and the same 1.2 μm Co powder were prepared, and these raw material powders were blended in the composition shown in Table 1, wet-mixed in a ball mill for 72 hours, and dried. After that, ISO ・ CNMG1204
08 was pressed into a green compact having the shape specified in Table 08, and the green compact was vacuum-sintered under the same conditions as shown in Table 1 to produce carbide substrates A to E, respectively. In Table 1,
The internal hardness (Rockwell hardness A scale) of each of the carbide substrates A to E is shown.

Next, the surfaces of these super hard substrates A to E
Then, with the honing applied, a normal chemical vapor deposition
The set shown in Tables 3 and 4 was used under the conditions shown in Table 2.
And average thickness of Ti compound layer and Al_TwoO_ThreeLayers
Formed, in this case columnar Al_Two O _Three The layer is formed at a predetermined thickness
Granular Al_TwoO_ThreeAfter formation of the layer, HCl: 3% by volume, H
_Two : Using a reaction gas having a composition consisting of the remaining
Air temperature: 1050 ° C, atmospheric pressure: 50 torr, holding
Time: 15 minutes, already formed granular
Al_TwoO_ThreeTreat the surface of the layer and adsorb Cl on the surface
Carbide tools coated with the present invention 1 to 1
2 and conventional coated carbide tools 1-12
Was.

Next, the coated carbide tools 1 to 12 according to the present invention will be described.
Workpiece: FC300 (hardness: HB180) round bar, Cutting speed: 400 m / min. , Depth of cut: 2 mm, feed: 0.4 mm / tooth, cutting time: 15 minutes, wet continuous high-speed high-feed cutting test of cast iron, and work material: JIS SCM440 (hardness: HB220) Round bar, cutting speed: 350 m / min. , Depth of cut: 2 mm. , Feed: 0.4 mm / tooth, cutting time: 10 minutes, dry continuous high-speed high-feed cutting test of the alloy steel was performed, and the flank wear width of the cutting blade was measured in each cutting test. Table 5 shows the results of these measurements.

[0010]

[Table 1]

[0011]

[Table 2]

[0012]

[Table 3]

[0013]

[Table 4]

[0014]

[Table 5]

[0015]

From the results shown in Tables 3 to 5, it can be seen that the upper part of the Al ₂ O ₃ layer in the hard coating layer is a columnar Al ₂ O ₃ layer and the lower part is a granular Al ₂ O ₃ layer. The coated cemented carbide tools 1 to 12 of the present invention are characterized in that the columnar Al ₂ O ₃ layer is formed of the granular Al ₂ O ₃ in comparison with the conventional coated cemented carbide tools 1 to 12 which are entirely composed of the granular Al ₂ O ₃ layer. High strength and toughness compared to the O ₃ layer, so even in high-speed high-feed cutting of cast iron and steel, which is a severe cutting condition, the cutting edge does not chip and exhibits excellent cutting performance for a long time On the other hand, in the conventional coated carbide tools 1 to 12, the granular A
It is evident that chipping of the cutting edge is unavoidable due to the l ₂ O ₃ layer, and in any case, the service life can be shortened in a relatively short time. As described above, the coated cemented carbide tool of the present invention has a hard coating layer of Al ₂
The O ₃ layer is composed of an upper portion of the columnar Al ₂ O ₃ layer and a lower portion of the granular Al ₂ O ₃ layer, thereby having excellent chipping resistance. In addition to continuous cutting and intermittent cutting at high speeds, even when used under severe conditions such as high speed cutting, high speed high feed and high depth of cut, chipping does not occur on the cutting edge, and it is excellent for a long time It exhibits cutting performance, and therefore can sufficiently cope with high performance and high output of the cutting device, and also contributes to labor saving.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C30B 29/20 C30B 29/20

Claims (2)

[Claims] 1. A hard coating layer containing an aluminum oxide layer having a thickness of 2 to 20 μm on a surface of a tungsten carbide-based cemented carbide substrate.
In a surface-coated cemented carbide cutting tool formed by chemical vapor deposition and / or physical vapor deposition with an average layer thickness of m, the aluminum oxide layer constituting the hard coating layer is mainly composed of an aluminum oxide having an α-type crystal structure. And an upper portion and a lower portion (substrate side) have different crystal structures, and the upper portion has a crystal structure in which columnar crystal grains are arranged in parallel in a vertical direction,
A cutting tool made of a surface-coated cemented carbide having a hard coating layer having excellent chipping resistance, wherein the lower side is formed of an aluminum oxide layer having a granular crystal structure. 2. The method according to claim 1, wherein the surface of the tungsten carbide-based cemented carbide substrate comprises a Ti carbide layer, a nitride layer, a carbonitride layer, an oxide layer, a carbonate layer, a nitride oxide layer, and a carbonitride layer. Hard coating layer composed of one or more of the following Ti compound layers and an aluminum oxide layer:
In a surface-coated cemented carbide cutting tool formed by chemical vapor deposition and / or physical vapor deposition with an average layer thickness of m, the aluminum oxide layer constituting the hard coating layer is mainly composed of an aluminum oxide having an α-type crystal structure. And an upper portion and a lower portion (substrate side) have different crystal structures, and the upper portion has a crystal structure in which columnar crystal grains are arranged in parallel in a vertical direction,
A cutting tool made of a surface-coated cemented carbide having a hard coating layer having excellent chipping resistance, wherein the lower side is formed of an aluminum oxide layer having a granular crystal structure.