JP3353705B2 - Cutting tools made of artificial diamond coated hard sintered material with excellent chipping resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tungsten carbide-based cemented carbide substrate (hereinafter referred to as a cemented carbide substrate), a titanium carbonitride-based cermet substrate (hereinafter referred to as a cermet substrate), and a silicon nitride-based ceramic substrate (hereinafter referred to as a "cermet substrate"). The artificial diamond coating formed on the surface of the hard sintered material substrate made of any one of the above-mentioned ceramic substrates shows excellent chipping resistance and exhibits excellent cutting performance over a long period of time. The present invention relates to a cutting tool made of a sintered material (hereinafter, referred to as a diamond-coated tool).

[0002]

2. Description of the Related Art Conventionally, Japanese Patent Application Laid-Open No.
As described in JP-A-6402, the hot filament method described in JP-A-58-91100 and the microwave method described in JP-A-58-110494 are applied to the surface of a hard sintered material substrate. And JP-A-58-1351.
A diamond-coated tool formed by forming an artificial diamond coating (hereinafter, referred to as a diamond coating) with an average layer thickness of 5 to 200 μm using a gas phase synthesis method such as a high-frequency plasma method described in Japanese Patent No. 17 is known. It is well known that the diamond coated tool is used for continuous cutting or intermittent cutting of Al-Si alloy, Cu-Zn alloy, graphite, fiber reinforced plastic (FRP), and the like.

[0003]

On the other hand, in recent years, there has been a strong demand for labor saving and energy saving for cutting work, and with this, cutting work has tended to be accelerated. The diamond coating is very hard, but it is very brittle, so chipping (small chipping) tends to occur on the cutting edge especially when interrupted cutting is performed at high speed. At present, the service life is reached in a very short time.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above-mentioned viewpoint, as a result of conducting research with a focus on diamond coatings, particularly diamond coatings, generally, when forming a diamond coating by a gas phase synthesis method, for example, by a microwave plasma method, microwave power: 4 to 8 kW Atmospheric pressure: 40 to 70 Torr, Substrate surface temperature: 800 to 900 ° C., Reaction gas composition: O ₂ / CH ₄ / H ₂ = _{1/2 by} volume ratio
When the film is formed under the following conditions, a film consisting only of diamond crystal grains is formed, and the reaction gas composition in the above-described conditions for forming the diamond crystal film is relatively changed to CH.
₄ reaction gas composition, that is, reaction gas composition: O ₂ / CH ₄ / H ₂ = 1/1 by volume ratio
0 to 30/80 to 120, it is well known that the formed film is made of amorphous carbon. 45
, Followed by forming a film under the above-mentioned amorphous carbon film forming conditions by setting the formation time to 5 to 10 minutes, and repeating the process at least 5 times or more alternately. When an average layer thickness of 5 μm is formed, the formed film is observed by a scanning electron microscope in a longitudinal section, as shown in a schematic diagram (× 2000) in FIG. Thin carbon layers alternately stacked at a fine pitch and have a mixed structure of laminating grains exhibiting a striped pattern and diamond crystal grains,
Further, in this case, the diamond crystal grain film formation time and the amorphous carbon film formation time are each set to the above-mentioned 15 minutes.
If the adjustment is made within the range of 45 minutes and 5 to 10 minutes, the mutual ratio of the laminated grains and the diamond crystal grains can be adjusted, and the resulting diamond coating has excellent chipping resistance due to the presence of the laminated grains. Therefore, even if this diamond coated tool with this diamond coating is used to perform intermittent cutting at high speed, it will exhibit excellent cutting performance over a long period of time without occurrence of cutting edge chipping. The research results were obtained.

The present invention has been made based on the results of the above-mentioned research, and a scanning-type material is provided on a surface of a hard sintered material substrate made of one of a super-hard substrate, a cermet substrate, and a ceramic substrate. In a longitudinal section observation by an electron microscope, a diamond grain thin layer and an amorphous carbon thin layer are alternately stacked at a fine pitch, and a laminated grain exhibiting a stripe pattern,
Diamond coated tool having excellent chipping resistance, comprising an artificial diamond coating having a mixed structure of diamond crystal grains and having the laminated grains occupying 10 to 70 area% in an average layer thickness of 5 to 200 μm. It is characterized by the following.

In the diamond-coated tool of the present invention, the ratio of the laminated grains of the diamond coating constituting the tool is 10 to 10.
When the ratio is less than 10 area%, the desired excellent chipping resistance of the diamond coating cannot be secured if the ratio is less than 10 area%, and when the ratio exceeds 70 area%, abrasion proceeds rapidly. For this reason, the ratio is preferably 30 to 50%. Also, the average layer thickness of the diamond coating is 5 to 200 μm, if the value is less than 5 μm, it is not possible to exhibit the desired excellent wear resistance over a long period of time, while if the value exceeds 200 μm, This is because chipping or chipping is likely to occur in the cutting blade, and the value is desirably 20 to 50.
It is good to be μm.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the diamond coated tool of the present invention will be specifically described with reference to examples. As raw material powder,
Average particle size: 1.5 μm fine WC powder, 3 μm medium WC powder, 1.2 μm (Ti, W) CN (weight ratio, same hereafter, TiC / TiN / WC = 24/20 / 5
6) Powder (1.3 μm) of (Ta, Nb) C (TaC /
NbC = 90/10) powder, 1 μm Cr powder, and 1.2 μm Co powder were prepared, and these raw material powders were used as WC (fine particles) -2% (Ta, Nb) C-6% Co ( WC (fine) -6% Co-0.5% Cr (for base B), WC (medium) -5% (Ti, W) CN-4% (Ta, N)
b) C-6% Co (for base C), WC (medium grain) -5% (Ti, W) CN-3% (Ta, N
b) C-8% Co-0.5% Cr (for substrate D), and wet-mixed in a ball mill for 72 hours, dried, and then subjected to ISO standard SPGN1210308 at a pressure of 1 ton / cm ^2. Press molding into a green compact having a defined throw-away tip shape,
After holding at 1400 ° C. for 1 hour in a vacuum atmosphere of 5 Torr, vacuum sintering was performed under furnace cooling conditions to produce substrates A to D each made of a superhard substrate as a hard sintered material substrate.

[0008] As raw material powders,
TiCN powder having a predetermined average particle size in the range of ２2 μm
Powder, TiN powder, TaC powder, NbC powder, WC powder,
Mo _Two C powder, VC powder, ZrC powder, Cr_Three C_Two powder
Powder, Co powder, and Ni powder are prepared.
The powder is: TiCN-10% TiN-9% TaC-3% NbC-9
% WC-10% Mo_TwoC-3% Co-4% Ni (base a)
For), TiCN-4% TaC-6% NbC-10% WC-9%
Mo_Two C-5% ZrC-7% Co (for base b), TiCN-16% TiN-3% TaC-6% WC-6%
Mo_Two C-2% Cr_ThreeC_Two -4% Co-5% Ni (substrate
c), TiCN-7% TaC-13% WC-5% VC-7% C
o-4% Ni (for base d), and wet-mixed in a ball mill for 24 hours
And after drying, 1 ton / cm^Two ISO standard at pressure
Throwaway chips defined in SPGN1210308
Press forming into green compacts of shape, then these green compacts,
Under the following conditions, that is, from room temperature to 1300 ° C
1.5 ° C./min in a vacuum atmosphere of 0.05 torr
The temperature was raised at a rate of temperature rise, and after the temperature was raised to 1300 ° C.,
torr nitrogen atmosphere at the same temperature increase rate of 1500
Temperature up to 1500 ℃ and kept at 1500 ℃ for 60 minutes in the same atmosphere
After that, sintering under the condition of furnace cooling
Substrates a to d composed of a cermet substrate as
Manufactured.

Further, as raw material powders,
Si ₃ N ₄ having a predetermined average particle size in the range of １1 μm
Powder, Y ₂ O ₃ powder, La ₂ O ₃ powder, Er ₂ O ₃ powder, Yb ₂ O ₃ powder, SiO ₂ powder, MgO powder, and ZrN powder were prepared, and these raw material powders were Si ₃ N ₄ − 5% Y ₂ O ₃ -2% MgO-1.5% Si
O ₂ -3% ZrN (for substrate A), Si ₃ N ₄ -8% La ₂ O ₃ -3% MgO-2% SiO
₂ -8% ZrN (for base _{b), Si 3 N 4 -5%} Er 2 O 3 -1% MgO-0.5% S
iO ₂ -3% ZrN (for substrate C), Si ₃ N ₄ -4% Yb ₂ O ₃ -1% MgO-3% SiO
₂ -8% ZrN (for base e), incorporated in the composition of polyethylene glycol was added as a molding binder, were mixed for 48 hours wet ball mill using ethyl alcohol as a solvent, and dried in a spray dry over Granules are mixed with a uniaxial press.
ISO standard SPGN12103 at a pressure of ton / cm ²
08 into a compact having a shape of a throw-away tip, and then these compacts are first subjected to 5 MPa (50 MPa).
0 kgf / cm ² ) in a pressurized nitrogen atmosphere at 1800 ° C. for 2 hours under a primary sintering condition.
00MPa (1000kgf / cm ²⁾ and then, the temperature was maintained at the same 1800 ° C., after 1 hour hold time at this temperature, the substrate A-d comprising a ceramic substrate as a hard sintered material substrate by to sintering under the conditions of cooling Was manufactured respectively.

Then, on each surface of these various substrates, a microwave power generator: 5 kW, an atmospheric pressure: 50 Torr, a substrate surface temperature: 850 ° C., a reaction gas composition: O ₂ / CH ₄ , using a microwave plasma generator. / H ₂ = 1/3 by volume ratio
/ 100, formation time of one time: 15 to 45 minutes, conditions for forming a diamond grain coating film, microwave power: 4.5 kW, atmospheric pressure: 50 Torr, substrate surface temperature: 800 ° C., reaction gas composition: O ₂ / CH ₄ / H ₂ = volume ratio: 10 /
100, formation time of one time: 5 to 10 minutes, the formation conditions of the amorphous carbon film were alternately changed 5 times or more, and the film formation time of each time was adjusted within the above range. The diamond coated tools 1 to 12 of the present invention were formed by forming a diamond coating having the average layer thickness shown in 1 and a laminated grain ratio measured by longitudinal section observation with a scanning electron microscope.
Was manufactured respectively. For the purpose of comparison, conventional diamond coated tools 1 to 12 as shown in Table 2 were manufactured under the same conditions except that the diamond coating was formed only under the same conditions as the diamond grain coating. did.

Next, among the various diamond-coated tools obtained as a result, the diamond-coated tools 1 to 4 of the present invention and the conventional diamond-coated tools 1 to 4 are as follows: Work material: Al-20% by weight of Si alloy Equal interval 4
This vertical grooved round bar, cutting speed: 600 m / min, feed: 0.1 mm / rev, depth of cut: 0.5 mm, cutting time: 20 minutes, dry intermittent high-speed cutting test of Al-Si alloy, Invention diamond coated tools 5-8 and conventional diamond coated tools 5
About 8: Work material: Cu-35% by weight Zn Round bar with four longitudinal grooves at regular intervals in the longitudinal direction, Cutting speed: 1200 m / min, Feed: 0.2 mm / rev, Cutting depth: 1.0 mm, Cutting time: 20 minutes, Dry intermittent high-speed cutting test of Cu-Zn alloy under the following conditions: Diamond coated tools 9-12 of the present invention and conventional diamond coated tools 9-12: Work material: length direction of graphite, etc. A dry intermittent high-speed cutting test of graphite was conducted under the following conditions: a round bar with four vertical grooves, a cutting speed of 800 m / min, a feed of 0.5 mm / rev, a cutting depth of 1.0 mm, and a cutting time of 20 minutes. In each cutting test, the flank wear width of the cutting edge was measured. Tables 1 and 2 show the measurement results.

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

From the results shown in Tables 1 and 2, all of the diamond coated tools 1 to 12 of the present invention have a diamond coating having excellent chipping resistance due to the presence of the laminated grains, and mixed with the laminated grains. Despite high wear resistance due to coexisting diamond crystal grains, it shows even better chipping resistance despite high-speed interrupted cutting.
While exhibiting excellent cutting performance over a long period of time,
It is clear that the conventional diamond coated tools 1 to 12 in which the diamond coating is made only of diamond crystal grains cause chipping of the cutting edge in such high-speed interrupted cutting, which leads to a relatively short service life. . As described above, in the diamond coated tool of the present invention, the diamond coating constituting the diamond coated tool has excellent chipping resistance, and can perform not only continuous cutting and interrupted cutting under normal conditions, but also particularly interrupted cutting at high speed. Even when it is performed, it exhibits excellent chipping resistance over a long period of time, and therefore has industrially useful characteristics such as being useful for saving labor and energy in cutting.

[Brief description of the drawings]

FIG. 1 is a schematic diagram (20) showing a longitudinal sectional structure of a diamond coating constituting a diamond coating tool of the present invention, which is observed by a scanning electron microscope.
00 times).

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 16/00-16/56 B23B 27/14 C30B 29/04

Claims (1)

(57) [Claims] 1. A longitudinal section by a scanning electron microscope on a surface of a hard sintered material substrate made of any one of a tungsten carbide-based cemented carbide substrate, a titanium carbonitride-based cermet substrate, and a silicon nitride-based ceramic substrate. Observation shows a mixed structure of diamond grains and diamond grains, in which a diamond crystal thin layer and an amorphous carbon thin layer are alternately stacked at a fine pitch to form a striped pattern and a mixed structure of diamond grains, and the stacked grains have an area of 10 to 70 areas. %. A cutting tool made of an artificial diamond-coated hard sintered material having excellent chipping resistance, wherein an artificial diamond coating occupying a percentage of% is formed with an average layer thickness of 5 to 200 μm.