JP2002254229A - Drill made of surface-coated cemented carbide and excellent in wear resistance in high speed cutting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drill made of surface-coated cemented carbide and excellent in wear resistance in high speed cutting. SOLUTION: A surface-coated cemented carbide drill includes a tungsten carbide group cemented carbide substrate whose surface is laminated alternately with a first thin layer and a second thin layer, each having an average layer thickness of 0.01 to 0.1 μm. Further, a hard coating layer having an overall average thickness of 0.8 to 10 μm is physically vapor-deposited. The first thin layer is constituted of either of a single-phase structure layer composed of a compound nitride having a specified composition ratio of Ti and Al, or a single-phase structure layer composed of a compound carbonitride having the specified composition ratio of Ti and Al, or both of the layers. The second thin layer is constituted of either of a compound nitride layer having the specified composition ratio of Ti, and Al, or a mixed-phase structure layer having a structure where an aluminum oxide layer is dispersed and distributed on a base metal composed of a compound carbonitride layer having the specified composition ratio of Ti and Al, at a rate of 5 to 40 area % by a structural observation with a scanning electron microscope, or both of the layers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface coated cemented carbide drill (hereinafter referred to as a coated cemented carbide drill) which exhibits excellent wear resistance when used for high-speed cutting of steel or the like accompanied by high heat generation. It is about).

[0002]

2. Description of the Related Art Conventionally, in general, for example, in FIG. 1A, a schematic front view and FIG. 1B, in a schematic cross-sectional view of a groove forming portion, for drilling and cutting a work material such as steel or cast iron. Various types of coated cemented carbide drills are used as drills having the exemplified shapes and further miniature drills. Also, as the coated cemented carbide drill, a tungsten carbide-based cemented carbide substrate (hereinafter referred to as a cemented carbide substrate) is used. A composite nitride of Ti and Al [hereinafter, referred to as (Ti, Al) N] layer and Ti
And a composite carbonitride of Al and Al (hereinafter, referred to as (Ti, Al) CN), or a hard coating layer composed of both layers, with an average layer thickness of 0.8 to 10 μm. Coated carbide drills are known.

Further, (Ti, Al) N layer and (Ti, Al) CN which are hard coating layers of the above coated carbide drill
The layer uses, for example, an arc ion plating apparatus which is a kind of a physical vapor deposition apparatus schematically shown in FIG.
In a state where the inside of the apparatus is heated to a temperature of 700 ° C. by, for example, setting the atmosphere to a vacuum of 3 Pa with a heater, the anode electrode and the cathode electrode (evaporation source) on which a Ti—Al alloy having a predetermined composition is set are heated. For example, arc discharge is generated under the conditions of a voltage: 35 V and a current: 90 A, and at the same time, a nitrogen gas or a nitrogen gas and a methane gas are introduced into the apparatus as a reaction gas, while a bias voltage of, for example, -200 V is applied to the carbide substrate. It is also well known that they are formed under the conditions of application.

[0004]

On the other hand, labor saving and energy saving for cutting such as drilling in recent years,
In addition, there is a strong demand for cost reduction, and in accordance with this, the cutting process tends to be accelerated in conjunction with the high performance of the cutting machine. There is no problem when used for drilling under ordinary conditions such as cutting, but if this is used under high-speed cutting conditions, the high heat generated during drilling and cutting, especially the tip and groove including the cutting edge surface At present, the thin-walled portion undergoes thermoplastic deformation which causes uneven wear, and as a result, the progress of wear on the cutting edge surface is promoted, and the service life is relatively short.

[0005]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoints, the above-mentioned conventional coated carbide drills were focused on, and research was conducted to improve the heat-resistant plastic deformation properties thereof. (A) For example, as raw material powders, Ti powder and Al powder, and Aluminum oxide (hereinafter referred to as Al ₂ O ₃ )
Using a powder, these raw material powders are blended in a predetermined blending ratio, mixed and then pressed into a green compact, and the green compact is formed under ordinary conditions, for example, in a vacuum atmosphere at 500 to 600
Sintering at a predetermined temperature in a range of ℃ for a predetermined time to form a sintered body having a predetermined composition, and using this sintered body as a cathode electrode (evaporation source), for example, When a hard coating layer is formed on the surface of the super-hard substrate by introducing a nitrogen gas or a nitrogen gas and a methane gas as a reaction gas with an ion plating apparatus, the formed hard coating layer becomes (Ti, Al) N or _{(Ti, Al) Al 2 O} 3 phase in the matrix consisting of CN be a one with the dispersion distribution organization.

(B) The substrate of the above (a) is represented by a composition formula: [T
When expressed as i _1-x Al _x ] N and [Ti _1-x Al _x ] C _1-m N _m , the atomic ratio X: 0 was measured by an Auger spectrometer at the center in the thickness direction. .30 to 0.70, m:
Satisfies 0.6~0.99 (Ti, Al) N and (Ti, Al) specified in the CN, and the ratio of Al ₂ O ₃ phase dispersed distributed to the matrix in the structure observation with a scanning electron microscope Assuming 5 to 40 area%, the resulting mixed phase microstructure layer, together with the excellent toughness of the green body, together with the Al ₂ O ₃
High hardness due to phase and excellent heat resistance.

(C) One or both of the single-phase texture layer composed of the (Ti, Al) N layer and the (Ti, Al) CN layer, and the mixed phase texture layer of (b) With alternate lamination with either or both of them,
These individual layer thicknesses are 0.01 to 0.1 μm in average layer thickness.
When a hard coating layer having a total average layer thickness of 0.8 to 10 μm is formed in a state of being a very thin thin layer, the hard coating layer is formed by a thinning alternately laminated structure of the two thin layers. Characteristics: excellent toughness (breakage resistance) due to the single phase structure layer (hereinafter referred to as first thin layer), high hardness and excellent heat resistance due to the mixed phase structure layer (hereinafter referred to as second thin layer) (Heat-resistant plastic deformation), the resulting coated carbide drill is
Even when this is used for high-speed cutting of steel or cast iron with high heat generation, there is no chipping or chipping at the tip including the cutting edge and the thin part of the groove forming part, and it causes uneven wear. Therefore, since the occurrence of thermoplastic deformation is significantly suppressed, excellent wear resistance is exhibited over a long period of time. The research results shown in (a) to (c) above were obtained.

The present invention has been made based on the above research results.
The surface of the cemented carbide substrate, 0.8 to 10
The hard coating layer physically deposited with a total average layer thickness of μm
The first thin layer and the second thin layer having an average layer thickness of 0.01 to 0.1 μm.
The first thin layer is composed of alternating layers of
i_1-XAl_X] N and [Ti_1-XAl_X] C_{1- m}N_mIn table
If it is passed, it will be
X: 0.30 to 0.70, m:
(Ti, Al) N layer satisfying 0.6 to 0.99;
One of the single phase structure layers composed of the (Ti, Al) CN layer
Or both, and wherein the second thin layer is of composition
Formula: [Ti_1-XAl_X] N and [Ti_1-XAl_X] C_1-
mN_mWhen expressed in terms of, the Auger spectral component at the center in the thickness direction
X: 0.30 to 0.7 in atomic ratio as measured by the analyzer.
0, m: (Ti, Al) N satisfying 0.6 to 0.99
Layer and a (Ti, Al) CN layer,_Two
O_ThreeThe phase is 5 to 40 by microscopic observation with a scanning electron microscope.
Mixed-phase tissue layer having a structure distributed and distributed at a ratio of area%
High-speed cut-off that consists of one or both of
Characterized by coated carbide drills that exhibit excellent wear resistance when milled
It has.

In the coated cemented carbide drill according to the present invention, the average thickness of each of the first thin layer and the second thin layer constituting the alternate lamination of the hard coating layers is 0.01 to 0.1 μm.
The reason why m is that in any of the thin layers, when the average layer thickness is less than 0.01 μm, the characteristics of each thin layer, that is, excellent toughness by the first thin layer, high hardness by the second thin layer When the hard coating layer cannot be provided with excellent heat resistance, the average thickness of each of the thin coating layers exceeds 0.1 μm.
That is, the reason is that the thermoplastic deformation due to the first thin layer and the decrease in fracture resistance due to the second thin layer appear in the hard coating layer.

Further, in the coated carbide drill according to the present invention, the (Ti, Al) N layer constituting the base of the single-phase texture layer of the first thin layer and the mixed-phase texture layer of the second thin layer of the hard coating layer. And Al in the (Ti, Al) CN layer increases the hardness with respect to TiN and TiCN, and thus forms a solid solution in order to improve the wear resistance.
(Ti _1-x Al _x ) N and (Ti _1-x Al _x ) C
In _1-m N _m, X value is the atomic ratio (hereinafter the same), is less than 0.3 can not be ensured the desired abrasion resistance, whereas if the value exceeds 0.7, cutting surfaces The X value was determined to be 0.3 to 0.7 for the reason that chipping and chipping are likely to occur in the thin portion of the tip portion and the groove forming portion including the above. Desirably, the X value is set to 0.35 to 0.65.

The C component in the (Ti, Al) CN layer has the effect of improving the hardness.
l) The CN layer has a relatively high hardness as compared with the (Ti, Al) N layer. If it exceeds 99, the predetermined hardness improving effect cannot be obtained, while if the ratio of the C component exceeds 0.4, that is, if the m value is less than 0.6, the toughness rapidly decreases. The value was defined as 0.6-0.99. Desirably, the m value is 0.8 to
0.9 is better.

Further, as described above, the Al ₂ O ₃ phase dispersed and distributed in the base material of the mixed phase structure layer of the second thin layer of the hard coating layer is provided with high hardness and excellent heat resistance as described above. Even with high-speed cutting accompanied by heat generation, the thin portion of the tip portion including the cutting edge surface and the groove forming portion has an effect of remarkably suppressing the occurrence of thermoplastic deformation which causes uneven wear. If the proportion of the Al ₂ O ₃ phase in the mixed phase tissue layer is less than 5 area% by microscopic observation with a scanning electron microscope, the desired effect cannot be obtained for the above-mentioned action. Since the resulting toughness rapidly decreases, the ratio of the Al ₂ O ₃ phase is set to 5 to 40 area%, preferably 10 to 30 area%.

The hard coating layer has an overall average thickness of 0.8.
When the thickness is 0.8 μm, the desired excellent wear resistance cannot be ensured. On the other hand, when the thickness exceeds 10 μm, the formation of the tip and groove including the cutting edge surface is not possible. This is because chipping and chipping easily occur in the thin portion of the portion.

[0014]

Next, the coated carbide drill of the present invention will be described in detail with reference to examples. As raw material powder,
Average particle size: Medium-coarse WC powder having 5.5 μm;
8 μm fine WC powder, 1.3 μm TaC powder, 1.2 μm NbC powder, 1.2 μm ZrC powder,
2.3 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C powder, 1.8 μm
Co powder and 1.2 μm carbon (C) powder were prepared, and these raw material powders were respectively blended into the blending compositions shown in Table 1, and further added with wax, and added with acetone in acetone.
After mixing with a ball mill for an hour and drying under reduced pressure, 100 MPa
Is pressed into various green compacts having a predetermined shape at a pressure of 6 mm. After raising the temperature and holding at this temperature for 1 hour, sintering was performed under furnace cooling conditions to form three types of round bar sintered bodies for forming a carbide substrate having a diameter of 8 mm, 13 mm, and 26 mm. In the combinations shown in Table 1, the diameter x length of the groove forming portion was 4 mm x 13 m, respectively, by grinding from the three types of round rod sintered bodies of
Carbide substrates A-1 to A-10 having dimensions of m, 8 mm × 22 mm, and 16 mm × 45 mm were produced, respectively.

Further, Ti powder and A powder are used as raw material powders.
These powders were further mixed with a predetermined composition using wet powder and Al ₂ O ₃ powder, wet-mixed with a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. The powder is placed in a vacuum of 6 Pa,
Sintering at a predetermined temperature in the range of 00 ° C. for one hour to obtain various kinds of sintering for forming the second thin layer with the contents of Ti, Al, and Al ₂ O _{3 being} the predetermined contents. Body manufactured. Further, various Ti-Al alloys having different contents of Ti and Al were separately prepared for forming the first thin layer.

Next, these super hard substrates A-1 to A-1
0 was ultrasonically cleaned in acetone, dried, and mounted on a rotary table in a usual arc ion plating apparatus also illustrated in FIG. 2, while a cathode electrode (evaporation source) was First, a Ti-Al alloy for forming a thin layer having various component compositions and a sintered body for forming a second thin layer are mounted at predetermined positions in the apparatus, and metal Ti for bombarding is also mounted. While maintaining the vacuum at 0.5 Pa, the inside of the apparatus was heated to 700 ° C. with a heater.
An arc discharge is generated between the metal Ti of the cathode electrode and the anode electrode by applying a bias voltage of 000 V, and the surface of the cemented carbide substrate is cleaned by Ti bombardment. A nitrogen gas and a methane gas are introduced to make a reaction atmosphere of 4 Pa, and a bias voltage applied to the superhard substrate is set to -100 V at the time of forming the first thin layer, and to -300 V at the time of forming the second thin layer.
The cathode electrode (Ti-for forming the first thin layer) is evacuated for 10 seconds between the formation of the first thin layer and the formation of the second thin layer. A
An arc discharge is generated between the aluminum alloy or the sintered body for forming the second thin layer) and the anode electrode, so that the surface of the cemented carbide substrate has a target composition and a target layer thickness shown in Tables 2 and 3 The first thin layer and the second thin layer are combined in the combinations shown in Table 4 and the hard coating layers having the same number of layers as shown in Table 4 are deposited to form a schematic front view in FIG. In the same manner as in (b), coated carbide drills 1 to 16 of the present invention each having a shape shown in a schematic cross-sectional view of the groove forming portion were manufactured.

For the purpose of comparison, the same conditions were used except that Ti-Al alloys having various component compositions were mounted as the cathode electrode (evaporation source) in the above-mentioned arc ion plating apparatus. The target composition and the target layer thickness (Ti,
By coating a hard coating layer composed of an (Al) N layer or a (Ti, Al) CN layer, a conventionally coated carbide drill 1 is formed.
To 13 were each manufactured.

Further, with respect to the various coated carbide drills obtained as a result, the composition and thickness of the various hard coating layers constituting the drills were determined by using an energy dispersive X-ray measuring apparatus, an Auger spectroscopic analyzer, and a scanning electron microscope. When measured using a microscope, the composition and the average layer thickness were substantially the same as the target composition and the target layer thickness shown in Tables 2 to 5 (comparison with the average value of measurement at five arbitrary locations).

Next, the coated carbide drills 1 to 1 according to the present invention will be described.
6 and the conventional coated carbide drills 1 to 13 of the present invention, the coated carbide drills 1 to 6 and the conventionally coated carbide drills 1 to 5 are: work material: plane dimension: 100 mm × 250 thickness: 50 mm
JIS S55C plate material, Cutting speed: 100 m / min. , Feed: 0.14 mm / rev, wet high-speed drilling test of carbon steel under the following conditions: coated carbide drills 7 to 11 of the present invention and conventional coated carbide drill 6
About 9: Work material: Plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS FC250 plate material, Cutting speed: 90 m / min. , Feed: 0.23 mm / rev, Wet high-speed drilling test of cast iron under the following conditions: coated carbide drills 12 to 16 of the present invention and conventional coated carbide drill 1
For 0 to 13, work material: plane size: 100 mm x 250 mm, thickness: 5
0 mm JIS SNCM439 plate, Cutting speed: 75 m / min. , Feed: 0.23 mm / rev, Wet high-speed drilling cutting test of alloy steel under the following conditions, and the flank of the cutting edge of the tip in any wet (using water-soluble cutting oil) high-speed drilling cutting test. Wear width is 0.
The number of drilling processes up to 3 mm was measured. The measurement results are shown in Tables 4 and 5, respectively.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

[0024]

[Table 5]

[0025]

According to the results shown in Tables 4 and 5, all of the coated carbide drills 1 to 16 according to the present invention, in which the hard coating layer is formed by alternately laminating the first thin layer and the second thin layer, are each made of steel. Even when processing is performed at high speed with high heat generation, the effect of the second thin layer having high hardness and excellent heat resistance significantly improves heat-resistant plastic deformability, so that the tip and groove forming portion including the cutting edge surface can be formed. There is no occurrence of thermoplastic deformation that causes uneven wear in thin parts,
Combined with the action of the first thin layer having excellent toughness (breakage resistance), it exhibits excellent wear resistance without occurrence of chipping or chipping, whereas the composition of the hard coating layer is A conventional coated carbide drill 1 substantially the same as the first thin layer
In No. 13, it is clear that the high heat generated at the time of high-speed cutting causes thermoplastic deformation which causes uneven wear, which significantly accelerates the progress of wear and leads to a relatively short service life. As described above, the coated carbide drill of the present invention exhibits excellent wear resistance not only in drilling and cutting under ordinary conditions such as various kinds of steel and cast iron, but also particularly in high-speed drilling and cutting. Because
It can sufficiently cope with labor saving, energy saving, and cost reduction of drilling.

[Brief description of the drawings]

FIG. 1A is a schematic front view illustrating a coated carbide drill, and FIG. 1B is a schematic cross-sectional view of the groove forming portion.

FIG. 2 is a schematic explanatory view of an arc ion plating apparatus.

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[Procedure amendment]

[Submission date] May 29, 2001 (2001.5.2)
9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

[0014]

Next, the coated carbide drill of the present invention will be described in detail with reference to examples. Next, the coated carbide end mill of the present invention will be specifically described with reference to examples. As raw material powders, an average grain size of any 1~3μm
WC powder, TiC powder, ZrC powder, VC powder,
TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder
Powder, TaN powder and Co powder were prepared, and these raw material powders were respectively blended into the blending composition shown in Table 1, and further added with wax, and ball-mixed in acetone for 24 hours, and dried under reduced pressure. Is pressed into various green compacts of a predetermined shape, and these green compacts are
1370 at a heating rate of 7 ° C./min in a vacuum atmosphere of 6 Pa
The temperature was raised to a predetermined temperature in the range of １４1470 ° C., maintained at this temperature for 1 hour, and then sintered under furnace cooling conditions to obtain a diameter of 8 m.
m, 13 mm, and 26 mm to form three types of round bar sintered bodies for forming a cemented carbide substrate, and further, from the three types of round bar sintered bodies, by grinding, in a combination shown in Table 1, The diameter x length of the groove forming part is 4mm x 13mm and 8mm x 2 respectively
Carbide substrates A-1 to A-10 having dimensions of 2 mm and 16 mm × 45 mm were produced, respectively.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Natsuki Ichinomiya 179 Nishi-Oike, Kanegasaki, Uozumi-cho, Akashi-shi, Hyogo 1 Inside MMC Kobelcourt Co., Ltd. (72) Inventor Akihiro Kondo Kanegasaki, Uozumi-cho, Akashi-shi, Hyogo 179 Nishi-Oike 1 FMC Term Co., Ltd. F term (reference) 3C037 CC02 CC04 CC09 4K029 AA04 BA54 BA58 BA64 BB02 BC02 BD05 EA01

Claims (1)

[Claims] 1. The surface of a tungsten carbide-based cemented carbide substrate
Hard-coated by physical vapor deposition with a total average layer thickness of 0.8 to 10 μm.
Coating layer has an average individual layer thickness of 0.01 to 0.1 μm
The first thin layer is formed by alternately laminating a first thin layer and a second thin layer._1-XAl_X] N and the same
[Ti_1-XAl_X] C_{1- m}N_mWhen expressed as
It was measured by Auger spectroscopy at the center.
X: 0.30 to 0.70, m: 0.6 to 0.99
Ti and Al composite nitride and Ti and Al composite carbon
Any of the single phase texture layers of nitride, or
The second thin layer is composed of both, and has a composition formula: [Ti_1-XAl_X] N and the same
[Ti_1-XAl_X] C_{1- m}N_mWhen expressed as
It was measured by Auger spectroscopy at the center.
X: 0.30 to 0.70, m: 0.6 to 0.99
Ti and Al composite nitride and Ti and Al composite carbon
Aluminum oxide phase is scanning type on nitride base
The structure was observed at a rate of 5 to 40 area% by microscopic observation with an electron microscope.
Any of the mixed phase tissue layers with scattered tissue
Or high speed cutting characterized by comprising both
Surface-coated cemented carbide drills with excellent wear resistance
Le.