JP2002263941A - Surface coated cemented carbide end mill with hard coating layer showing superior heat radiation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface coated cemented carbide end mill with a hard coating layer showing superior heat radiation. SOLUTION: The surface coated cemented carbide end mill comprises first thin layers and second thin layers alternately laminated on the surface of a tungsten carbide based 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 represented by composition formulae: [Ti1- XAlX]N and [Ti1- XAlX]C1-m Nm , by constituting one of a Ti-Al composite nitride layer and a Ti-Al composite carbon-nitride layer of both of them, where X is 0.30-0.70, and m is 0.6-0.99 by an atomic ratio in measurement at a central portion in the direction of thickness with an auger spectroscopy, 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. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-coated cemented carbide end mill (hereinafter, referred to as a coated cemented carbide end mill) capable of extending the life.

[0002]

2. Description of the Related Art Conventionally, in general, for surface processing, groove processing, and shoulder processing of a work material such as steel or cast iron, for example, FIG.
(A) is a schematic front view, and (b) is a coated carbide end mill having a shape exemplified by a schematic cross-sectional view of a cutting edge portion. The coated carbide end mill is a cemented carbide substrate. On the surface of the composite nitride of Ti and Al [hereinafter, (T
i, Al) N] layer and a composite carbonitride of Ti and Al [hereinafter, referred to as (Ti, Al) CN] layer, or a hard coating layer composed of both layers. ~ 1
A coated carbide end mill formed with an average layer thickness of 0 μm is known.

Further, a (Ti, Al) N layer and a (Ti, Al) N which are hard coating layers of the above coated carbide end mill.
The CN layer is heated to a temperature of 500 ° C., for example, by using an arc ion plating apparatus which is a kind of a physical vapor deposition apparatus schematically shown in FIG. In this state, an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which a Ti-Al alloy having a predetermined composition is set, for example, under the conditions of a voltage: 35 V and a current: 90 A, It is also well known that a nitrogen gas or a nitrogen gas and a methane gas are introduced as a reaction gas into the substrate, while the carbide substrate is formed under a condition of applying a bias voltage of, for example, -200V.

[0004]

On the other hand, in recent years, there has been a strong demand for labor saving, energy saving, and further cost reduction in cutting work, and with this, cutting work has been performed at high speeds in conjunction with high performance of cutting machines. However, in the case of the above-mentioned conventional coated carbide end mill, there is no problem if this is used for cutting under normal conditions such as steel or cast iron, but if this is used under high speed cutting conditions In particular, the high heat generated during cutting raises the temperature of the hard coating layer in particular, and as a result, the wear of the hard coating layer is further promoted. .

[0005]

Means for Solving the Problems Accordingly, the present inventors have
From the above point of view, focusing on the conventional coated carbide end mill described above, 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 end mill Constituent layer (Ti, Al) N
The layer and the (Ti, Al) CN layer are represented by a composition formula: [Ti _1-X
When expressed in Al _X] N and the _{[Ti 1- X Al X] C} 1-m N m, as measured by Auger spectroscopy apparatus in the thickness direction central portion, in terms of atomic ratio, X: from .30 to 0 .70, m: 0.
(Ti, Al) N layer satisfying 6 to 0.99 and (T
(i, Al) CN layer, and alternately laminated with an aluminum nitride (hereinafter abbreviated as AlN) layer, and these individual layer thicknesses are 0.01 to 0.1 in average layer thickness.
0.8-10 μm in a very thin layer of μm
m to form a hard coating layer having an overall average thickness of m
The excellent thermal conductivity and thermal stability of the N layer (hereinafter, referred to as the second thin layer) is provided by the thin hardened layered structure of the two thin layers so that the entire hard coating layer is provided. The heat dissipation of the layer is further improved, and even if the layer is exposed to high heat generated during high-speed cutting, overheating of the hard coating layer itself is significantly suppressed, while the (Ti, Al) N layer and (T
Since the hard coating layer has both the high hardness of the first thin layer and the excellent heat resistance due to the thinned alternately laminated structure of the (i, Al) CN layer (hereinafter, referred to as a first thin layer),
Even if this coated carbide end mill is used for high-speed cutting of steel, cast iron, etc. with high heat generation, the hard coating layer exhibits excellent heat dissipation, and the wear progresses due to its own overheating. Was suppressed, and the abrasion resistance was 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. This is characterized by a coated carbide end mill in which a hard coating layer exhibits excellent heat dissipation.

[0007] In the coated carbide end mill of 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.
The reason why the thickness is set to μm is that when the average thickness of any of the thin layers is less than 0.01 μm, the characteristics of each thin layer, that is, the high hardness and excellent heat resistance of the first thin layer, and the second thin layer The excellent thermal conductivity and thermal stability (heat dissipation) due to the layers cannot be provided sufficiently in the hard coating layer, while when the average layer thickness exceeds 0.1 μm, the thickness of each thin layer increases. This is because the first heat-dissipation phenomenon caused by the first thin layer and the accelerated wear phenomenon by the second thin layer appear on the hard coating layer.

The coated carbide end mill of the present invention is
To form the first thin layer of the hard coating layer (Ti, Al)
Al in the N layer and the (Ti, Al) CN layer is TiN
High temperature hardness and heat resistance to TiCN and TiCN
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 reason is that chipping is likely to occur on the bottom blade.
The value was defined as 0.3-0.7. Preferably, the X value is 0.3
It is good to be 5 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 layer thickness is 0.8 μm, the desired excellent wear resistance cannot be ensured. On the other hand, when the layer thickness exceeds 10 μm, the outer edge and the bottom edge of the cutting edge portion are not provided. This is because chipping is likely to occur.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide end mill of the present invention will be specifically described with reference to examples. As raw material powders, medium coarse WC powder having an average particle size of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, and ZrC of 1.2 μm
Powder, 2.3 μm Cr ₃ C ₂ powder, 1.5 μm V
C powder, 1.0 μm (Ti, W) C powder and 1.8 μm Co powder were prepared, and these raw material powders were respectively blended into the composition shown in Table 1. After being mixed in a ball mill for 24 hours and dried under reduced pressure, various green compacts having a predetermined shape are press-molded at a pressure of 100 MPa, and these green compacts are heated at 7 ° C./min in a vacuum atmosphere of 6 Pa. 1370-1470 ° C at speed
The temperature was raised to a predetermined temperature within the range described above, and after maintaining at this temperature for 1 hour, sintering was performed under furnace cooling conditions, and the diameter was 8 mm, 13 mm,
And three types of round bar sintered bodies for forming a carbide substrate having a diameter of 26 mm and formed from the above three types of round bar sintered bodies by grinding in the combinations shown in Table 1, and also in Table 1 The carbide substrates A-1 to A-10 having the dimensions (diameter x length of the cutting edge portion) and the shape shown in Table 1 were respectively manufactured.

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 coating a thin layer and a second thin layer in a combination shown in Table 3 and depositing a hard coating layer having the same number of layers as shown in Table 3, the coated carbide end mills 1 to 1 according to the present invention are deposited.
6 were each 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,
Conventionally coated carbide end mills 1 to 13 were manufactured by depositing a hard coating layer composed of an (Al) N layer or an (Ti, Al) CN layer.

Further, the composition and thickness of the various hard coating layers constituting the various coated carbide end mills obtained as described above were measured 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 end mill 1 of the present invention will be described.
-16 and the conventional coated carbide end mills 1-13, the coated coated carbide end mills 1-6 and the coated conventional carbide end mills 1-5 are: Work material: 100 mm × 250 plane dimension, 50 mm thickness JIS S55C plate material having a rotation speed of 1800 r. p. m. , Groove depth (cut): 3.5 mm, Table feed: 220 mm / min, Wet high-speed grooving test (using water-soluble cutting oil) of carbon steel under the following conditions: coated carbide end mills 7 to 11 of the present invention and For the conventional coated carbide end mills 6 to 9, work material: JIS SCM440 plate material having a plane size of 100 mm x 250 and a thickness of 50 mm, rotation speed: 2400 r. p. m. , Groove depth (cut): 3.5 mm, Table feed: 210 mm / min, Wet high-speed grooving test (using water-soluble cutting oil) of alloy steel under the following conditions: coated carbide end mills 12 to 16 of the present invention and For the conventional coated carbide end mills 10 to 13, a work material: a plate material of JIS FC250 having a plane dimension of 100 mm × 250 and a thickness of 50 mm, a rotation speed of 6600 rpm. p. m. , Groove depth (cut): 3 mm, Table feed: 380 mm / min, Wet cast high speed grooving test (using water-soluble cutting oil) under the following conditions: The cutting length was measured until the flank wear amount of the outer peripheral edge reached 0.1 mm, which is a standard of service life. The measurement results are shown in Tables 3 and 4, respectively.

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

[Table 3]

[0019]

[Table 4]

[0020]

From the results shown in Tables 3 and 4, the coated carbide end mills 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 all steel or cast iron. Even when the end milling is performed 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. And the excellent heat resistance and excellent heat resistance provided by the (Ti, Al) N layer and the (Ti, Al) CN layer of the first thin layer. In the conventional coated carbide end mills 1 to 10 in which the hard coating layer substantially consists of a single layer having the same composition as that of the first thin layer, the hard coating layer exhibits excellent wear resistance without generation. Hard coating due to high heat generated during cutting Temperature itself is increased, and therefore the wear progress is significantly accelerated, it is clear that lead to a relatively short time service life. As described above, the coated carbide end mill of the present invention can be used not only for cutting such as surface machining and grooving under various conditions such as steel and cast iron, but also for shoulder machining, and especially for high-speed machining of these. Therefore, it is possible to satisfactorily cope with labor saving and energy saving of the cutting process, and further lowering the cost because it exhibits excellent wear resistance.

[Brief description of the drawings]

FIG. 1 (a) is a schematic front view of a coated carbide end mill,
(B) is a schematic cross-sectional view of the cutting blade portion.

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

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[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]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide end mill of the present invention will be specifically described with reference to examples. WC powder having an average particle size of 1 to 3 μm,
TiC powder, ZrC powder, VC powder, TaC powder, Nb
C powder, Cr ₃ C ₂ powder, TiN powder, TaN powder,
And Co powder were prepared, and these raw material powders were listed in Table 1 respectively.
And further mixed with a wax, mixed with a ball mill in acetone for 24 hours, dried under reduced pressure, and then press-molded into various compacts having a predetermined shape at a pressure of 100 MPa. Is heated in a vacuum atmosphere of 6 Pa at a heating rate of 7 ° C./min to a predetermined temperature within a range of 1370 to 1470 ° C., and after maintaining at this temperature for 1 hour, sintering is performed under furnace cooling conditions. Forming three types of round bar sintered bodies for forming a cemented carbide substrate having a diameter of 8 mm, 13 mm, and 26 mm;
Further, from the above three types of round bar sintered bodies, by grinding, a combination having the dimensions (diameter of cutting edge portion × length) and the shape shown in Table 1 in combination shown in Table 1 was obtained. Hard substrate A
-1 to A-10 were produced respectively.

Continued on the front page (72) Inventor Yusuke Tanaka 179 Nishi-Oike, Kanegasaki, Uozumi-cho, Akashi-shi, Hyogo 1 F-term in MMC Cobelco Tool Co., Ltd. 4K029 AA02 AA04 BA54 BA58 BB02 BC10 BD05 CA04 EA01 FA05

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, which is composed of one or both of a composite nitride of Ti and Al and a composite carbonitride of Ti and Al, An end mill made of a surface-coated cemented carbide, wherein the second thin layer is made of aluminum nitride, wherein the hard coating layer exhibits excellent heat dissipation.