JPH11277304A - Milling tool excellent in wear resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display excellent wear resistance across a long term without the generation of the peel off of the hard covered layer of an edge chip, even if it is used for a high speed cutting. SOLUTION: In a milling tool on which a surface covered cemented carbide made edge chip formed a hard covered layer on its surface is mounted, a cemented carbide base body contains Co: 5-20% as a combination phase forming component, Cr and/or V: 0.1-2% as a combination phase forming component samely, Ti, Ta, Nb and Zr carbide, nitride and carbide-nitride and one kind or two kinds or more: 0.1-5 weight % out of the solid solution of these two kinds or more and the remainder has a composition consisting of WC as a dispersion phase forming component and an unavoidable impulity and further a surface layer formed by high temperature heating on whose surface a reaction product Com Wn C are distributed from the most surface side across the depth of 0.1-2 μm. This tool is constituted by the cemented carbide base body and also above hard covered layer is constituted by Ti compound layer or Al2 O3 layer by using MT-CVD method in either case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard coating layer constituting a cutting edge tip, which has excellent adhesion to the surface of a cemented carbide substrate, and therefore can be used even in high-speed cutting under severe cutting conditions. The present invention relates to a milling (milling) tool that exhibits excellent wear resistance over a long period of time because no peeling occurs.

[0002]

2. Description of the Related Art Conventionally, as shown in a plan view of FIG. 1, for example, a notch formed on a side surface of a tip end portion of a steel or cemented carbide rotary shank body has a surface of a cemented carbide substrate. There is known a milling tool in which a surface-coated cemented carbide cutting edge chip having a hard coating layer formed thereon is removably mounted by fixing means such as screwing. Also,
The hard coating layer constituting the cutting edge tip is formed by a normal high-temperature chemical vapor deposition method (hereinafter, referred to as HT-CVD method) or 1000 to 1150 ° C., which is the deposition temperature of the HT-CVD method.
It is also known that they are formed by a medium temperature chemical vapor deposition method (hereinafter, referred to as MT-CVD method) in which deposition is performed at a relatively low temperature of 700 to 980 ° C.

[0003]

On the other hand, labor saving and energy saving of cutting work have been remarkable in recent years, and accordingly, cutting conditions have tended to be further increased. When used under high speed conditions,
Due to the insufficient adhesion of the hard coating layer constituting the cutting edge tip to the surface of the cemented carbide substrate, the hard coating layer is liable to peel off, which significantly accelerates the progress of wear and is relatively short. At present, the service life is reached.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above-mentioned viewpoint, attention was paid to a milling tool, and a study was conducted to improve the adhesion of the hard coating layer to the surface of the cemented carbide substrate in the cutting edge tip constituting the milling tool. Is a% by weight (hereinafter,% means% by weight), Co: 5 to 20% as a binder phase-forming component, and Cr and / or V: 0.1 as a binder phase-forming component.
~ 2%, carbides, nitrides, and carbonitrides of Ti, Ta, Nb, and Zr as dispersed phase forming components (hereinafter, TiC, TiN, TiCN, TaC, TaN, TaN, respectively)
CN, NbC, NbN, NbCN, ZrC, ZrN, and ZrCN), and two or more solid solutions thereof (hereinafter, collectively referred to as (Ti, Ta, Nb, Z
r) C · N] or more:
1 to 5%, and the remainder has the same composition as tungsten carbide (hereinafter referred to as WC) as a dispersed phase forming component and unavoidable impurities, and the WC has an average particle size:
It has a fine grain structure of 0.1 to 1.5 μm. (B) The cemented carbide substrate of (a) is placed in a hydrogen atmosphere containing carbon dioxide gas or titanium tetrachloride, and the atmosphere pressure is 5
As 0～550Torr, when high-temperature heat treatment under the conditions of 5 to 15 minute hold at a temperature of 900 to 1000 ° C., in the surface portion, the composite carbides of Co and W across from the outermost surface to a predetermined depth (hereinafter, Co _m W _n C) is formed as a surface layer. (C) the reaction product Co _m W _n C is the surface of the cemented carbide substrate having a high-temperature heat forming surface layer distribution of the (b) in the surface portion, both using the MT-CVD method, a carbide layer of Ti , Nitride layer, carbonitride layer, carbonate layer, nitride layer,
And a carbonitride layer (hereinafter referred to as TiC layer and TiN layer, respectively)
Layer, TiCN layer, TiCO layer, TiNO layer, and Ti
A CNO layer), an aluminum oxide (hereinafter referred to as Al ₂ O ₃₎ formed by MT-CVD or HT-CVD if necessary. When the hard coating layer composed of the above-described layers is formed with an average thickness of 0.5 to 4.5 μm, the Ti
The adhesion of the compound layer to the surface of the cemented carbide substrate is significantly improved by the high-temperature heat-formed surface layer formed on the surface of the cemented carbide substrate, and thus the resulting surface-coated cemented carbide cutting blade. The milling tool to which the tip is attached exhibits excellent wear resistance over a long period of time because the hard coating layer of the cutting edge tip does not peel even when used for high-speed cutting. The research results shown in (a) to (c) above are shown.

The present invention has been made on the basis of the above-mentioned research results, and has a notch formed in a side surface of a tip portion of a steel or cemented carbide rotary shank body, and has a surface of a cemented carbide substrate. In a milling tool of a type in which a surface coated cemented carbide cutting edge having a hard coating layer formed thereon is detachably mounted, the cemented carbide substrate in the surface coated cemented carbide cutting edge is formed with a bonding phase. Co: 5 as a component
-20%, Cr and / or V: 0.1-2% as a binder phase-forming component, and (Ti,
One or more of Ta, Nb, Zr) C · N: 0.1 to 5%, the remainder having a composition comprising WC as a dispersed phase forming component and unavoidable impurities, W
C average particle size: 0.1 to 1.5 [mu] m of a fine grain structure, further reaction product Co _m W _n C over from the outermost surface to a depth of 0.1~2μm is distributed on the surface portion a high temperature TiC layer, TiN layer, TiCN layer, TiCO layer, TiN layer formed by using a cemented carbide substrate having a heat-formed surface layer, and each of the hard coating layers formed by the MT-CVD method.
An O layer, a Ti compound layer composed of one or more of TiCNO layers, or the Ti compound layer and M
Al ₂ formed by T-CVD or HT-CVD
O ₃ layer, and the average layer thickness is 0.5 to 4.5 μm
m, which is characterized by a milling tool having excellent wear resistance.

[0006] Next, in the milling tool of the present invention, the composition of the cemented carbide substrate in the cutting edge tip to configure this, the average particle size of the WC grains, Co _m W _n C distribution depth, and the hard coating layer The reason why the average layer thickness is limited as described above will be described. (A) Co content The Co component has the effect of improving sinterability and thus improving the toughness of the cemented carbide substrate, but if the content is less than 5%, the desired effect of improving toughness cannot be obtained. On the other hand, if the content exceeds 20%, not only does the wear resistance of the cemented carbide substrate itself deteriorate, but also the deformation tends to occur due to the heat generated during high-speed cutting. 5-
20%, preferably 8-12%.

(B) Cr and V content These components are based on the results observed with an optical microscope.
And form a solid solution in Co
And contribute to the refinement of WC grains.
Reaction product Co distributed in the heat-formed surface layer_m W_n C shape
Promotes the formation of the reaction product Co_m W_n Hardness by C
Has the effect of improving the adhesion of the porous coating layer.
If the amount is less than 0.1%, a desired effect can be obtained in the above-mentioned action.
On the other hand, if the content exceeds 2%, the above-mentioned effect is saturated.
In addition, since no further improvement effect appears,
The amount is fixed at 0.1 to 2%, preferably 0.4 to 0.8%
I did. In addition, Cr and V as the binding phase forming component
Is used as a raw material powder in the production of the cemented carbide substrate.
Cr and V carbides, nitrides, carbonitrides, and oxidations
Object [hereinafter, Cr_ThreeC_Two, CrN, Cr_TwoO_Three,
VC, VN, and V _TwoO_FiveAnd these are collectively referred to as
(Indicated by (Cr, V) C ・ N ・ O)
Is contained in Co as a binder phase forming component during sintering.
Is desirable.

(C) (Ti, Ta, Nb, Zr) CN
Content These components may form a dispersed phase to improve the wear resistance of the cemented carbide substrate.
If the content is less than 1%, the desired effect of improving wear resistance cannot be obtained. On the other hand, if the content exceeds 5%, the toughness decreases, so the content is 0.1 to 5%, desirably. 1
２．５2.5%.

(D) Average grain size of WC The cemented carbide substrate is strengthened by refining the WC grains. As described above, the fine structure is obtained by solidifying the Cr and / or V components into the binder phase. Melting and W used as raw material powder
C is obtained by reducing the particle size of the powder to 1.5 μm or less.
When the average particle size is less than 0.1 μm, a sharp decrease in wear resistance cannot be avoided.
1.5 μm, preferably 0.6 to 1.0 μm.

[0010] (e) The Co _m W is less than 0.1μm distribution depth its distribution depth of _n C, desired excellent against hard layer too small, the distribution ratio in the high temperature heating forming surface layer can not be ensured adhesion, whereas when the distribution depth exceeds 2 [mu] m, the distribution ratio of Co _m W _n C in the cemented carbide substrate outermost surface becomes too much, chipping the cutting edge tip which causes (Micro chipping) is likely to occur, so the distribution depth is set to 0.1 to 2 μm, preferably 0.5 to 1.5 μm.

(F) Average Layer Thickness of Hard Coating Layer If the average layer thickness is less than 0.5 μm, it is not possible to secure desired excellent wear resistance to the cutting edge tip, while the average layer thickness is 4 μm. If it exceeds 0.5 μm, chipping and chipping easily occur in the cutting edge tip, so the average layer thickness is set to 0.5 to 4.5 μm, preferably 1.0 to 2.0 μm.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A milling tool according to the present invention will be specifically described with reference to embodiments. First, as raw material powder,
WC powders having a predetermined average particle diameter in the range of 0.1 to 1.5 μm, various (Ti, Ta, Nb, Zr) CN powders each having an average particle diameter of 0.5 μm, and (C)
r, V) C—N—O powder and further a 0.5 μm Co powder were prepared, and these raw material powders were blended in the blending ratio shown in Table 1, wet-mixed in a ball mill for 72 hours, and dried. Press molding into a green compact with a pressure of 1 ton / cm ² ,
This green compact was placed in a vacuum of 1 × 10 ⁻³ torr,
Vacuum sintering is performed at a predetermined temperature in the range of 1500 ° C. for 1 hour, and has substantially the same composition as the above-mentioned composition, and is also composed of WC having an average particle size shown in Table 1. The cemented carbide substrate materials a to s constituting the cutting edge tips were formed.

Next, the surface of each of these cemented carbide substrate materials a to s was applied to the surface of each of the materials under the conditions shown in Table 2.
Cemented carbide substrate by Co _m W _n C to form a high-temperature heating forming surface layer distributed over a depth shown in A~S
Was manufactured.

Subsequently, a hard coating layer having the composition and the average thickness shown in Table 4 was formed on the surface of each of the cemented carbide substrates A to S under the conditions shown in Table 3 to obtain a length: 28 .9mm x width: 11.2mm x thickness: 5m
The cutting edge tips A to S of the present invention having the dimensions of m and the shapes shown in the plan view and the longitudinal sectional view in FIG. 1B were formed.

Furthermore each of the cutting insert A~S for those the invention, JIS · SCM440 (hardness: H _R C4
0) or a composition of WC-6% Co;
C is made of a cemented carbide having an average particle size of 1.5 μm, and has a total length of 200 mm × front half length: 120 mm × back half length: 80 mm × front half diameter: 30 mm × back half diameter: 32 mm. The milling tool 1 according to the present invention is obtained by screwing in a combination shown in Table 6 into a notch formed on a side surface of a tip portion of a rotating shank body having dimensions and a shape shown in a plan view in FIG. To 19 were each manufactured.

For the purpose of comparison, as shown in Table 5, in place of the cemented carbide substrates A to S having the high-temperature heat-formed surface layer, cemented carbide substrate materials a to s without the formation were used. Comparative milling tools 1 to 1 shown in Table 6 under the same conditions except that comparative cutting edge tips a to s formed by using
19 were each manufactured.

The resulting milling tools 1 to 19 of the present invention and the comparative milling tools 1 to 19 are obtained as follows: Work material: SKD61 (hardness: HR C53); : 1000m / min, feed per tooth: 0.4mm / tooth, axial depth of cut: 0.2mm, radial depth of cut: 0.35mm, cutting time: 1 hour Milling,
The flank wear width of the cutting edge tip was measured. Table 6 shows the measurement results.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Table 3]

[0021]

[Table 4]

[0022]

[Table 5]

[0023]

[Table 6]

[0024]

From the results shown in Table 6, all of the milling tools 1 to 19 of the present invention exhibit excellent wear resistance because the hard coating layer of the cutting edge tip constituting the milling tools does not peel off. On the other hand, in all of the comparative milling tools 1 to 19, the hard coating layer of the cutting edge chip is peeled off during the cutting, and this peeling significantly accelerates the progress of wear, and the service life is relatively short. It is clear that As described above, according to the milling tool of the present invention, the adhesiveness of the hard coating layer of the cutting edge tip constituting the cutting tool to the surface of the cemented carbide substrate is distributed in the high-temperature heat-formed surface layer formed on the substrate surface. _m W _n C has been significantly improved, so that it can be used not only under normal cutting conditions, but also in high-speed cutting, without causing peeling of the hard coating layer of the cutting edge tip and excellent wear resistance. For a long time.

[Brief description of the drawings]

FIG. 1A is a plan view of a milling tool and FIG. 1B is a plan view and a vertical cross-sectional view of a cutting edge tip constituting the milling tool.

Claims (2)

[Claims] 1. A surface coated cemented carbide cutting in which a hard coating layer is formed on a surface of a cemented carbide substrate in a notch formed on a side surface of a tip portion of a rotating shank body made of steel or cemented carbide. In a milling tool of a type in which a blade tip is detachably mounted, the cemented carbide substrate in the above-mentioned surface-coated cemented carbide cutting blade tip is made to contain 5 to 20% by weight of Co as a bonding phase forming component, and also as a bonding phase forming component. Cr and / or V:
0.1 to 2% by weight, one or more of Ti, Ta, Nb, and Zr carbides, nitrides, and carbonitrides as a dispersed phase forming component, and two or more solid solutions thereof: 0.1-5
% By weight, with the balance comprising tungsten carbide as a dispersed phase forming component and unavoidable impurities, wherein the tungsten carbide has an average particle size of 0.1 to 1.5 μm.
A cemented carbide substrate having a high-temperature heat-formed surface layer on the surface portion of which a reaction-generated composite carbide of Co and W is distributed over a depth of 0.1 to 2 μm from the outermost surface. And wherein the hard coating layer is formed of a Ti carbide layer, a nitride layer, a carbonitride layer, a carbonitride layer, a carbonitride layer, and a carbonitride oxide formed by a medium temperature chemical vapor deposition method. A milling tool having excellent wear resistance, comprising a Ti compound layer composed of one or more of the material layers and having an average layer thickness of 0.5 to 4.5 μm. 2. A surface-coated cemented carbide cutting tool in which a hard coating layer is formed on a surface of a cemented carbide substrate in a notch formed in a side surface of a tip portion of a steel or cemented carbide rotary shank main body. In a milling tool of a type in which a blade tip is detachably mounted, the cemented carbide substrate in the above-mentioned surface-coated cemented carbide cutting blade tip is made to contain 5 to 20% by weight of Co as a bonding phase forming component, and also as a bonding phase forming component. Cr and / or V:
0.1 to 2% by weight, one or more of Ti, Ta, Nb, and Zr carbides, nitrides, and carbonitrides as a dispersed phase forming component, and two or more solid solutions thereof: 0.1-5
% By weight, with the balance comprising tungsten carbide as a dispersed phase forming component and unavoidable impurities, wherein the tungsten carbide has an average particle size of 0.1 to 1.5 μm.
A cemented carbide substrate having a high-temperature heat-formed surface layer on the surface portion of which a reaction-generated composite carbide of Co and W is distributed over a depth of 0.1 to 2 μm from the outermost surface. And wherein the hard coating layer is formed of a Ti carbide layer, a nitride layer, a carbonitride layer, a carbonitride layer, a carbonitride layer, and a carbonitride formed by a medium temperature chemical vapor deposition method. A Ti compound layer composed of one or more of the above-mentioned material layers, and an aluminum oxide layer formed by a medium temperature chemical vapor deposition method or a high temperature chemical vapor deposition method, and having an average layer thickness of 0. 5-4.5
Milling tool with excellent wear resistance, characterized by having a thickness of μm.