JP3419140B2 - Surface coated cutting 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 single hard layer comprising a compound layer containing at least one titanium carbonitride oxide layer on the surface of a cemented carbide substrate or a cermet substrate (hereinafter referred to as "substrate"), or This is a surface-coated cutting tool formed by chemical vapor deposition of a composite hard layer, and exhibits excellent cutting performance in highly efficient interrupted cutting (high-speed interrupted cutting, high-feed milling cutting) of even harsher steel. The present invention relates to a surface-coated cutting tool.

[0002]

2. Description of the Related Art Conventionally, surface-coated cutting tools which are commercially available include a hard layer made of titanium oxycarbonitride or a titanium oxycarbonitride layer on the surface of a substrate by a chemical vapor deposition method. A surface-coated cutting tool is known in which a composite hard layer composed of one or more composite layers of carbides, nitrides, carbonitrides and carbonates, and aluminum oxide layers is coated. It is also well known that cutting tools are used for continuous cutting and interrupted cutting of steel and cast iron.

However, since the conventional chemical vapor deposition method for forming a hard layer made of titanium oxycarbonitride is carried out at a high temperature of 1000 ° C. or higher, a decarburized layer is formed at the boundary between the substrate and the coating layer, and the strength of the substrate is increased. Is reduced and the coating layer is easy to peel from the substrate. Therefore, when cutting steel under severe conditions such as high speed and high feed cutting using a titanium oxycarbonitride layer surface coated cutting tool produced by conventional chemical vapor deposition, Breaking and peeling of the coating layer occurred, and a sufficient cutting tool life could not be obtained.

Therefore, according to the X-ray diffraction (11
1), (200) and (220) plane peak intensities are I (1
11), I (200), I (220), I (220)> I (111) with the maximum peak at the (220) plane.
A method has also been proposed in which a hard layer made of titanium oxycarbonitride such as> I (200) is coated by physical vapor deposition to prevent a decrease in strength and improve adhesion (Japanese Patent Publication No. 63- 19590).

[0005]

However, in recent years, there is a strong demand for labor saving and shortening of the cutting process, and accordingly, there is a tendency that intermittent cutting is performed under more severe conditions. When intermittent cutting is performed under severe conditions, the cutting edge is broken in a short time during cutting, and the service life is reached in a relatively short time. In contrast to the current situation, the hard coating layer made of titanium oxycarbonitride formed by the physical vapor deposition method has a small decrease in the strength of the substrate, but the adhesion is still low, and the abrasion resistance is further improved by the conventional chemical vapor deposition. Since it is lower than that obtained by the method, when performing high-efficiency interrupted cutting (high-speed interrupted cutting, high-feed milling) of steel etc., abnormal wear, peeling, chipping, etc. will prolong the tool life. I couldn't.

[0006]

From this point of view, the present inventors have eliminated the drawbacks of the coating layer formed by the chemical vapor deposition method and the physical vapor deposition method, and even if intermittent cutting is performed under severe conditions, While conducting research to develop a surface-coated cutting tool with a long tool life, Ti (C _u
N _v O _w ) (where u, v, and o are atomic ratios of C, N, and O), these are u + v + w = 1 and u ≧ v>w>.
In a cutting tool coated with a titanium oxycarbonitride layer satisfying the condition of 0, 0.05 ≧ w, peak intensity I of (111), (200), and (220) planes in X-ray diffraction
(111), I (200), I (220) are I (11
1)> I (220)> I (200), a surface-coated cutting tool coated with a titanium oxycarbonitride layer has a much longer life than interrupted cutting under severe conditions. That is, the research result that the energy consumption is improved was obtained.

The present invention has been made based on the results of such research. (1) Ti (C _u N _v O _w ) (however,
u, v, and o are atomic ratios of C, N, and O), these are titanium carbonitride oxide layers satisfying the conditions of u + v + w = 1, u ≧ v>w> 0, and 0.05 ≧ w. In a cutting tool coated with a hard layer made of, the carbon oxynitride layer of titanium is (111), (200), (22) by X-ray diffraction.
0) plane peak intensities I (111), I (200), I
(220) becomes I (111)> I (220)> I (20
0) a hard layer surface-coated cutting tool which is a carbonitride oxide layer of titanium, such as (2) Ti (C _u N _v O _w ) (however,
u, v, and o are atomic ratios of C, N, and O), these are u + v + w = 1, at least one layer of titanium carbon satisfying the conditions of u ≧ v>w> 0, and 0.05 ≧ w. A composite hard layer including a nitride oxide layer and a multilayer including one or more of a titanium carbide layer, a nitride layer, a carbonitride layer and a carbon oxide layer, and an aluminum oxide layer. In a cutting tool formed by coating a layer, the carbon oxynitride layer of titanium is (111), (200) by X-ray diffraction,
Peak intensities I (111) and I (20) of the (220) plane
0) and I (220) are I (111)> I (220)> I
(200) A surface-coated cutting tool which is a carbonitride oxide layer of titanium as described in (200).

Ti (C _u N _v O _w ) (however,
u, v, and o are atomic ratios of C, N, and O), these are titanium carbonitride oxide layers satisfying the conditions of u + v + w = 1, u ≧ v>w> 0, and 0.05 ≧ w. Is the intensity ratio I (111) / I (2
00) is more preferably 1.5 or more.

Therefore, the present invention provides (3) Ti (C _u N _v O _w ) (where u, v, and o are
In terms of the atomic ratio of C, N and O), these are u + v + w =
The titanium carbonitride oxide layer satisfying the conditions of 1, u ≧ v>w> 0, 0.05 ≧ w has an intensity ratio I (111) / I (200) of the first peak and the third peak by X-ray diffraction. ) Is 1.5
The surface-coated cutting tool according to the above (1) or (2) is also characterized. The thickness of the carbonitride oxide layer of titanium is preferably in the range of 1 to 20 μm.

The X-ray diffraction peak intensity of the present invention is I
A titanium oxycarbonitride layer such that (111)> I (220)> I (200) has a relatively low reaction temperature in the chemical vapor deposition device of 800 to 1000 ° C. (preferably 8).
50 to 950 ° C.) and TiCl 2 as a reaction gas.
_4: 0.5 to 10 volume%, CH ₃ CN: 0.01~5.
0% by volume, N ₂ : 0 to 50% by volume (N ₂ may not be contained in some cases), CO: 0.01 to 5.0% by volume, balance H ₂
Can be formed by reacting a mixed gas consisting of

The intensity ratio I (111) / I of the first peak and the third peak of the titanium oxycarbonitride layer measured by X-ray diffraction.
To make (200) 1.5 or more, the above Ti
Cl _4: 0.5 to 10 volume%, CH ₃ CN: 0.01~
5.0% by volume, N ₂ : 0 to 50% by volume (N ₂ may not be contained in some cases), CO: 0.01 to 5.0% by volume, and the balance H _{2 at the} beginning of the reaction start. CH of reaction gas
It is possible to form more efficiently by reducing the amount of ₃ CN and then increasing the amount of the reaction, and further
i (C _u N _v O _w ) (where u, v, o are C, N,
U + v + w = 1 in the atomic ratio of O, u ≧ v>w>
In order to form a carbonitride oxide layer satisfying the condition of 0, 0.05 ≧ w, the above TiCl ₄ : 0.5 to 10% by volume, CH
₃ CN: 0.01 to 5.0 volume%, N _2: (sometimes N ₂ is not included) 0-50 volume%, CO: 0.01 to
CH ₃ C in a mixed gas consisting of 5.0% by volume and the remaining H _2.
It can be formed by adjusting the gas component ratio of N, N ₂ and CO. Intensity ratio I (1) of the first peak and the third peak by the X-ray diffraction of the titanium oxycarbonitride layer
The most preferable range of 11) / I (200) is 1.5 to
It is 10.

[0012]

Example 1 As a raw material powder, a medium-grain WC powder having an average particle diameter of 3 μm, a coarse-grain WC powder having an average particle diameter of 5 μm, and an average particle diameter of 1.5 μm (Ti, W) ) C (TiC / WC = 30/70 by weight) powder, also having an average particle size of 1.2 μm (Ti, W) (CN) (TiC / TiN / WC = 24/20/56 by weight) Powder, also having an average particle size of 1.3 μm (Ta, Nb) C
(TaC / Nb = 90/10 by weight ratio) powder and Co powder having the same average particle diameter: 1.2 μm were prepared, and these raw material powders were blended in the composition shown in Table 1 and wet-mixed for 72 hours with a ball mill. And dried, then ISO standard CNM
G120408 (Cemented Carbide Substrates A to C) and S
EEN12048AFTN1 (Cemented Carbide Base D) was press-molded into a green compact having a shape determined, and the green compact was sintered under the conditions shown in Table 1 to prepare Cemented Carbide Substrates A to D.

[0013]

[Table 1]

Next, after honing the surfaces of these cemented carbide substrates A to D, a chemical vapor deposition apparatus was used to obtain the results shown in Table 2.
The TiCNO layer is formed under the coating conditions a to f shown in Table 1, and the other hard layers are formed under the following conditions, so that the coating of the present invention has a coating layer having a composition and an average layer thickness shown in Tables 3 to 4. Cutting tools 1-8, comparative coated cutting tools 1-2 and conventional coated cutting tools 1-2 were produced. Conditions for forming hard layers other than TiCNO layer (however,%
Is the volume%) as follows.

TiC hard layer reaction gas composition: 2% TiCl ₄ -5% CH ₄ -H ₂ reaction temperature: 1020 ° C. reaction pressure: 50 Torr

TiCN hard layer reactive gas composition: 2% TiCl ₄ -0.3% CH ₃ CN-
20% N ₂ —H ₂ Reaction temperature: 850 ° C. Reaction pressure: 50 Torr

TiN hard layer reaction gas composition: 2% TiCl ₄ -25% N ₂ -H ₂ reaction temperature: 900 ° C. reaction pressure: 200 Torr

TiCO hard layer reactive gas composition: 2% TiCl ₄ -2% CH ₄ -1% Co
-H ₂ reaction temperature: 1020 ° C. reaction pressure: 50 Torr

Al ₂ O ₃ hard layer reaction gas composition: 3% AlCl ₃ -5% CO ₂ -0.3%
H ₂ S-H ₂ Reaction temperature: 1000 ° C. Reaction pressure: 50 Torr

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

Using the obtained coated cutting tools 1 to 6 of the present invention, the comparative coated cutting tool 1 and the conventional coated cutting tool 1, a work material: SCM440 (hardness: HB220), four-grooved round bar cutting speed: 300m / min Feed: 0.25mm / rev Depth of cut: 1.5mm Cutting time: 10min Cutting oil: A high speed intermittent cutting test (outer diameter cutting) under the condition of no cutting is performed, the amount of wear is measured, and the form of wear is further investigated. The results are shown in Table 5.

Further, using the coated cutting tools 7 to 8 of the present invention, the comparative coated cutting tool 2 and the conventional coated cutting tool 2, the work material: SCM440 (hardness: HB220) square material cutting speed: 300 m / min per blade Feed: 0.35 mm / blade depth: 2.0 mm Cutting time: 10 min A high speed milling test was conducted under the condition of no cutting oil: and the amount of wear was measured, and the form of wear was examined. The results are shown in Table 5. It was

[0025]

[Table 5]

[0026]

From the results shown in Tables 3 to 5, the coated cutting tools 1 to 8 of the present invention are compared with the comparative coated cutting tools 1 and 2 and the conventional coated cutting tools 1 and 2 which deviate from the conditions of the present invention. Thus, it can be seen that normal wear is maintained and the life of the cutting tool is greatly improved. In this example, cemented carbide was used as the substrate, but exactly the same results were obtained with cermet. Therefore, the surface-coated cutting tool of the present invention can reduce the number of times of cutting tool replacement and the like to improve the work efficiency and reduce the cost as compared with the conventional surface-coated cutting tool, and thus can greatly contribute to the development of the industry. .

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-2-131802 (JP, A) JP-A-3-31469 (JP, A) JP-A-63-195268 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B23B 27/14 C23C 16/30

Claims (3)

(57) [Claims] 1. A Ti (C _u N _v O _w ) film formed on the surface of a WC-based cemented carbide or cermet substrate (hereinafter referred to as a substrate).
(However, u, v, and o are atomic ratios of C, N, and O), these are u + v + w = 1, u ≧ v>w> 0, 0.0
In a cutting tool formed by coating a titanium oxycarbonitride layer satisfying the condition of 5 ≧ w, the titanium oxycarbonitride layer is (111), (200), (22) by X-ray diffraction.
0) plane peak intensities I (111), I (200), I
(220) becomes I (111)> I (220)> I (20
A hard-layer surface-coated cutting tool, which is a carbonitride oxide layer of titanium as described in 0). 2. When Ti (C _u N _v O _w ) (where u, v and o are atomic ratios of C, N and O) is shown on the surface of the substrate,
These are u + v + w = 1, u ≧ v>w> 0, 0.05 ≧
including at least one titanium oxycarbonitride layer satisfying the condition of w, and further comprising one or two of a titanium carbide layer, a nitride layer, a carbonitride layer and a carbon oxide layer, and an aluminum oxide layer. In a cutting tool formed by coating a composite hard layer composed of a multi-layer including the above, the titanium oxycarbonitride layer is formed by X-ray diffraction (11
1), (200), (220) plane peak intensity I (11
1), I (200), and I (220) are I (111)> I
A surface-coated cutting tool, characterized in that it is a titanium oxycarbonitride layer such that (220)> I (200). 3. The Ti (C _u N _v O _w ) (however,
u, v, and o are atomic ratios of C, N, and O), these are titanium carbonitride oxide layers satisfying the conditions of u + v + w = 1, u ≧ v>w> 0, and 0.05 ≧ w. Is the intensity ratio I (111) / I (2
00) is 1.5 or more, The surface-coated cutting tool according to claim 1 or 2, wherein.