JP2002263933A - Surface coated cemented carbide drill with hard coating layer showing superior heat radiation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface coated cemented carbide drill with a hard coating layer showing superior heat radiation. SOLUTION: The surface coated cemented carbide drill comprises first thin layers and second thin layers alternately laminated on the surface of a tungsten carbide based cemented carbide substrate with their individual average layer thicknesses being 0.01-0.1 μm and a hard coating layer physically deposited thereon with its total average layer thickness being 0.8-10 μm. The first thin layer is constructed by one of a Ti-Al composite nitride layer and a Ti-Al composite carbonitride layer or both of them, satisfied with an atomic ratio X: 0.30-0.70, m: 0.6-0.99 in measurement at a central portion in the direction of thickness with an Auger spectroscopy, if represented by composition formulae: [Ti1- XAlX]N and [Ti1- XAlX]C1-m Nm , and the second thin layer is constructed by an aluminum nitride layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed cutting of steel and the like, particularly when high heat is generated, in which a hard coating layer exhibits excellent heat radiation properties, suppresses the progress of abrasion due to overheating, and further enhances use. The present invention relates to a drill made of a surface-coated cemented carbide (hereinafter, referred to as a coated carbide drill) capable of extending the life.

[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 shapes shown and further miniature drills, and the surface of a tungsten carbide-based cemented carbide substrate (hereinafter referred to as a cemented carbide substrate) is used as the coated carbide drill. A composite nitride of Ti and Al [hereinafter, referred to as (Ti, Al) N] layer
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, a (Ti, Al) N layer or (Ti, Al) CN which is a hard coating layer 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 with this, cutting tends to be accelerated in conjunction with the high performance of the cutting machine. There is no problem when used for drilling cutting under normal conditions such as, but if this is used under high-speed cutting conditions, the high heat generated during drilling cutting will increase the temperature of the hard coating layer, especially As a result, abrasion of the hard coating layer is further promoted, so that the service life of the hard coating layer can be reached in a relatively short time at present.

[0005]

Means for Solving the Problems Accordingly, the present inventors have
From the above-mentioned viewpoints, focusing on the above-mentioned conventional coated carbide drill, as a result of conducting research especially to suppress the temperature rise of the hard coating layer during high-speed cutting, the hard coating layer of the conventional coated carbide drill The (Ti, Al) N layer and the (Ti, Al) CN layer, which are the constituent layers, are formed by a composition formula: [Ti _1-x Al _x ] N
When expressed as [Ti _1-x Al _x ] C _1-m N _m , X: 0.30 to 0.70, m in atomic ratio as measured by an Auger spectrometer at the center in the thickness direction. : 0.6 to 0.9
(Ti, Al) N layer and (Ti, Al)
After specifying the CN layer, this is alternately laminated with an aluminum nitride (hereinafter, referred to as AlN) layer, and the individual layer thicknesses thereof are extremely thin, having an average layer thickness of 0.01 to 0.1 μm. When the hard coating layer having a total average layer thickness of 0.8 to 10 μm is formed in the layered state, the excellent thermal conductivity and thermal stability of the AlN layer (hereinafter, referred to as a second thin layer) can be obtained. The entire thin hard coating layer is provided by the thinned alternately laminated structure with both thin layers, and as a result, the heat dissipation of the hard coating layer is further improved, and even if the hard coating layer itself is exposed to the high heat generated during high speed cutting, Overheating is significantly suppressed, while the (Ti, Al) N layer and (Ti, Al)
Since the hard coating layer has both the high hardness of the first thin layer and the excellent heat resistance due to the thinned alternating layered structure of the CN layer (hereinafter, referred to as a first thin layer), the resulting coated carbide drill is obtained. Even if this is used for high-speed cutting of steel or cast iron, especially with high heat generation, the hard coating layer exhibits excellent heat dissipation, suppressing the progress of abrasion due to its own overheating, and abrasion resistance. The research results show that the quality will be further improved.

The present invention has been made on the basis of the above research results, and has a surface of a super-hard substrate of 0.8 to 10 mm.
The hard coating layer physically vapor-deposited with a total average layer thickness of μm is composed of alternately laminated first and second thin layers each having an average layer thickness of 0.01 to 0.1 μm. , 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:
The (Ti, Al) N layer and the (Ti, Al) CN layer satisfying 0.6 to 0.99 or both, and the second thin layer is formed of an AlN layer. The feature of the coated carbide drill is that the hard coating layer exhibits excellent heat dissipation.

In the coated 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.
When the average thickness of any of the thin layers is less than 0.01 μm, the characteristics of each of the thin layers, that is, the high hardness and excellent heat resistance of the first thin layer,
The excellent heat conductivity and thermal stability (heat dissipation) of the second thin layer cannot be sufficiently provided in the hard coating layer. On the other hand, if the average layer thickness exceeds 0.1 μm, the thickness of each thin layer increases. This is because the problem of the layer, that is, the phenomenon of lowering the heat radiation property by the first thin layer and the phenomenon of promoting the abrasion progress by the second thin layer appear in the hard coating layer.

Further, the coated carbide drill according to the present invention has an odor.
(Ti, Al) N constituting the first thin layer of the hard coating layer
Al in the layer and the (Ti, Al) CN layer is TiN and
High temperature hardness and heat resistance to TiCN and TiCN
Is to form a solid solution to improve wear resistance.
Therefore, the composition formula: (Ti_1-XAl_X) N and (Ti)
_1-XAl_X) C_1-mN_m, The X value of which is the atomic ratio (the same applies hereinafter),
If it is less than 0.3, the desired wear resistance can be secured.
On the other hand, if the value exceeds 0.7, the tip
Chipping and chipping easily occur in the thin part of the part and groove formation part
For this reason, the X value was determined to be 0.3 to 0.7.
Desirably, the X value is set to 0.35 to 0.65.

Further, the C component in the (Ti, Al) CN layer has an effect of improving hardness, so that (T
The (i, Al) CN layer has a relatively high hardness as compared with the (Ti, Al) N layer. In this case, the ratio of the C component in the above composition formula is less than 0.01, that is, the m value is 0.9
If it exceeds 9, 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 set to 0.
It is good to be 8 to 0.9.

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.

[0011]

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, and 1.
8 μm Co powder was prepared, and each of these raw material powders was blended to the composition shown in Table 1, further added with wax, and ball-milled in acetone for 24 hours, and dried under reduced pressure. Various green compacts are press-molded, and these green compacts are heated to a predetermined temperature within a range of 1370 to 1470 ° C. in a vacuum atmosphere of 6 Pa at a temperature rising rate of 7 ° C./min. After holding 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 processing, in the combinations shown in Table 1, the diameters and lengths of the groove forming portions were 4 mm × 13 mm, 8 mm × 22 mm, and carbide substrates A-1 to A having dimensions of 16 mm × 45 mm, respectively.
-10 were each produced.

Next, these super hard substrates A-1 to A-1
0 was ultrasonically cleaned in acetone and 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 Ti-Al alloy for forming first thin layer and metal A for forming second thin layer having various component compositions
1 was mounted at a predetermined position in the apparatus, and also a metal Ti for bombarding was mounted. First, the inside of the apparatus was evacuated and heated to 700 ° C. with a heater while maintaining the vacuum at 0.5 Pa. For the carbide substrate rotating on the rotary table-
An arc discharge is generated between the metal Ti of the cathode electrode and the anode electrode by applying a DC bias voltage of 1000 V, and the surface of the super-hard substrate is cleaned by Ti bombardment. Introduce nitrogen gas or nitrogen gas and methane gas as reaction gas into
a, and a DC bias voltage of -200 V is applied to the superhard substrate rotating on the rotary table. The second thin layer is formed by using nitrogen gas as a reaction gas in the apparatus. The reaction was carried out under a condition of applying a pulsed bias voltage of -300 V to the carbide substrate rotating on the rotary table, and a (Ti, Al) CN layer was used as the first thin layer. Only when forming the first thin layer, the cathode electrode (the first thin layer forming Ti- 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 second thin layer forming metal Al) and the anode electrode, so that the first composition having the target composition and the target layer thickness shown in Table 2 is formed on the surface of the cemented carbide substrate.
By depositing the thin layer and the second thin layer in a combination shown in Table 3 and also by depositing a hard coating layer having the number of layers alternately shown in Table 3, a schematic front view in FIG. (B) Coated carbide drills 1 to 13 of the present invention each having the shape shown in the schematic cross-sectional view of the groove forming portion were manufactured.

For the purpose of comparison, the same conditions were used under the same conditions 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. On the surface of the cemented carbide substrate, (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 10 were respectively 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 are 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 compositions and the target layer thicknesses in Tables 2 to 4 (comparison with the average values of measurements at five arbitrary locations).

Next, the coated carbide drills 1 to 1 according to the present invention will be described.
3 and conventional coated carbide drills 1 to 10, of the present invention coated carbide drills 1 to 5 and conventional coated carbide drills 1 to 4, work material: plane dimension: 100 mm × 250 thickness: 50 mm
JIS S50C plate material, Cutting speed: 95 m / min. , Feed: 0.15 mm / rev, Wet high-speed drilling test of carbon steel under the following conditions: coated carbide drills 6 to 9 of the present invention and conventional coated carbide drills 5 to 5
About 7, work material: plane dimensions: 100 mm x 250 mm, thickness: 5
0 mm JIS SNCM439 plate, Cutting speed: 80 m / min. , Feed: 0.16 mm / rev, Wet high-speed drilling test of alloy steel under the following conditions: coated carbide drills 10 to 13 of the present invention and conventional coated carbide drills 8 to 10 : 100mm x 250mm, thickness: 5
0 mm JIS FC250 plate material, Cutting speed: 100 m / min. , Feed: 0.25mm / rev, Wet high-speed drilling cutting test of cast iron under the following conditions. The number of holes drilled until the width reached 0.3 mm was measured. The measurement results are shown in Tables 3 and 4, respectively.

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

[Table 3]

[0019]

[Table 4]

[0020]

According to the results shown in Tables 3 and 4, the coated carbide drills 1 to 13 according to the present invention, in which the hard coating layer is composed of alternating multiple layers of the first thin layer and the second thin layer, are all steel or cast iron. Even when drilling at high speed with high heat generation, the hard coating layer exhibits excellent heat dissipation due to the excellent thermal conductivity and thermal stability of the second thin layer, and the hard coating layer itself is overheated. The first thin layer (Ti, A
l) In combination with the excellent high hardness provided by the N layer and the (Ti, Al) CN layer and the excellent heat resistance, it exhibits excellent wear resistance without occurrence of chipping or chipping. Conventional coated carbide drills in which the hard coating layer consists essentially of a single layer having the same composition as the first thin layer.
In any case, it is clear that the temperature of the hard coating layer itself rises due to the high heat generated at the time of high-speed cutting, so that the progress of wear is remarkably accelerated, and the service life is reached in a relatively short time. 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. Therefore, it is possible to sufficiently and satisfactorily cope with labor saving and energy saving of drilling and cutting and further cost reduction.

[Brief description of the drawings]

FIG. 1A is a schematic front view of a coated carbide drill, and FIG.
FIG. 3 is a schematic cross-sectional view of the groove forming portion.

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

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 11, 2001 (2001.4.1
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

[0011]

Next, the coated carbide drill of the present invention will be described in detail with reference to examples. As raw material powder,
WC powder having an average particle size of 1 to 3 μm, Ti
C powder, ZrC powder, VC powder, TaC powder, NbC powder
Powder, Cr ₃ C ₂ powder, TiN powder, TaN powder, and
Co powder was prepared, and these raw material powders were respectively blended to the composition shown in Table 1, and further added with wax, and ball-mixed in acetone for 24 hours, and dried under reduced pressure.
Each compact is press-molded at a pressure of 100 MPa into various compacts having a predetermined shape, and these compacts are compacted in a vacuum atmosphere of 6 Pa at 7 MPa.
The temperature was raised to a predetermined temperature in the range of 1370 to 1470 ° C. at a temperature rising rate of 1 ° C./min, held at this temperature for 1 hour, and then sintered under furnace cooling conditions to have diameters of 8 mm, 13 mm, and 26 m.
m, and three types of round bar sintered bodies for forming a cemented carbide substrate are formed. Further, from the three types of round bar sintered bodies described above, the diameter of the groove forming portion is determined by grinding in a combination shown in Table 1. × 4m in length
mx 13mm, 8mm x 22mm, and 16mm x 4
Carbide substrates A-1 to A-10 each having a size of 5 mm were manufactured. ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission Date] September 25, 2001 (2001.9.2)
5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

[0018]

[Table 3]

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yusuke Tanaka 179 Nishi-Oike, Kanegasaki, Uozumi-cho, Akashi-shi, Hyogo 1 F-term (reference) 3M037 CC02 CC04 CC09 4K029 AA04 BA54 BA58 BB02 BC02 BD05 CA03 CA04 DD06 EA01

Claims (1)

[Claims] 1. A hard coating layer physically vapor-deposited with a total average layer thickness of 0.8 to 10 μm on the surface of a tungsten carbide-based cemented carbide substrate, and a hard coating layer having an individual average layer thickness of 0.01 to 0.1 μm. 1 consists alternate lamination of thin layer and the second thin layer, the first thin layer, the composition formula: in _{[Ti 1-X Al X]} N and the _{[Ti 1-X Al X]} C 1- m N m When expressed, the atomic ratio was measured by an Auger spectrometer at the center in the thickness direction.
X: 0.30 to 0.70, m: 0.6 to 0.99, and / or a composite nitride of Ti and Al and a composite carbonitride of Ti and Al, or both. A drill made of a surface-coated cemented carbide, wherein the hard coating layer exhibits excellent heat dissipation, wherein the second thin layer is made of aluminum nitride.