JP2001219304A - Surface-coated cemented carbide cutting tool with excellent wear resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-coated cemented carbide cutting tool with excellent wear resistance. SOLUTION: This surface-coated cemented carbide cutting tool is formed by physically depositing a touch coating layer, comprising one type of single layer or two types of multiple layers of a compound nitride layer and compound carbonitride layer of Ti and Al having an average layer thickness of 0.5 to 15 μm, on the surface of a tool base body formed of a tungsten carbide based cemented carbide or a titanium carbonitride based cermet through an adhesive substrate coated layer formed of one type of single layer or two types of multiple layer of a carbide layer, nitride layer, and carbonitride layer of Ti having an average layer thickness of 0.1 to 10 μm. On that surface, as a wear resistance coating layer, an aluminum oxide based layer of 0.5 to 15 μm in average layer thickness, formed by substitutive solution of a part of Al with one or two or more types of Ti, Zr, and Hf with a ratio of 0.01 to 10 atomic % in content relative to Al, with the crystal structure of an aluminum oxide held undisturbed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool made of a surface-coated cemented carbide which has excellent wear resistance and therefore exhibits excellent cutting performance over a long period of time, for example, in continuous cutting and interrupted cutting of steel. Hereinafter, referred to as a coated carbide cutting tool).

[0002]

2. Description of the Related Art Conventionally, for example, an arc ion plating apparatus, which is a kind of physical vapor deposition apparatus schematically shown in FIG.
In a state heated to a temperature of ℃, an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which Ti or a Ti-Al alloy having a predetermined composition is set, and at the same time, methane gas is used as a reaction gas in the apparatus. And / or nitrogen gas is introduced, while a tungsten carbide (hereinafter abbreviated as WC) based cemented carbide or titanium carbonitride (hereinafter abbreviated as TiCN)
A tool base (hereinafter, collectively referred to as a carbide tool base) made of a base cermet and opposed to the anode electrode and the cathode electrode at a predetermined interval (for example, referred to as a carbide tool base) is supplied with a bias voltage of -120 V, for example. Under the conditions applied, the surface of the cemented carbide tool substrate is
-56565, 0.1 to 10
a carbide layer, a nitride layer, and a carbonitride layer of Ti having an average layer thickness of μm (hereinafter, TiC layer, TiN layer,
And a TiCN layer).
Through an adhesive undercoating layer consisting of multiple layers of
One of a composite nitride layer of Ti and Al [hereinafter, referred to as (Ti, Al) N] and a composite carbonitride [hereinafter, referred to as (Ti, Al) CN] layer having an average layer thickness of 15 μm Coated carbide cutting tools manufactured by physical vapor deposition of a tough coating layer consisting of a single layer or two or more layers are known.

[0003]

On the other hand, in recent years, FA and speed of cutting have been remarkable, and there is also a demand for labor saving and energy saving of cutting. As a result, the life of cutting tools has been extended. However, in the case of the above-mentioned conventional coated carbide cutting tool, the tough coating layer composed of the (Ti, Al) N layer and the (Ti, Al) CN layer has excellent strength and strength. Although it has toughness and shows good chipping resistance (the property that micro chipping does not easily occur on the tool cutting edge), it has insufficient wear resistance,
At present, the service life is reached in a relatively short time.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above-mentioned viewpoints, as a result of researching to improve the wear resistance of the conventional coated carbide cutting tool, (a) a normal Al ₂ O ₃ coating layer formed by physical vapor deposition is:
Excellent heat resistance, and because it has a high hardness, but is desirable in achieving the wear resistance improvement, the Al ₂ O
_{(3) The} coating layer is a tough coating layer (Ti, Al) N layer and (Ti, A) constituting the above-mentioned conventional coated carbide cutting tool.
l) Since the coated carbide cutting tool obtained by coating the surface of the conventional coated carbide cutting tool with the Al ₂ O ₃ layer is inferior in adhesion to the CN layer, the cutting edge is particularly When high-load intermittent cutting is performed under heavy cutting conditions such as high cutting and high feed, the Al ₂ O ₃ coating layer is liable to peel off and cannot be put to practical use.

(B) Toughness of the conventional coated carbide cutting tool
(Ti, Al) N layer and (Ti,
Al) On the surface of the CN layer, the above Al_TwoO_ThreePhysical vapor deposition of layers
When formed by, the ionic radius is significantly higher than that of Al
Large Ti, Zr, and Hf, ie, ionic radii
For 0.57 Å of Al,
Ti with ON radius of 0.76 Å, 0.8
7 angstroms Zr and 0.84 angstroms
One or more of the Hf of_Two
O_ThreeOf some of the Al atoms in the crystal structure of Al with Al
0.01 to 10 atomic%, preferably 0.1 to 10 atomic%.
Solid solution contained in a substituted form at a rate of 02 to 5 atomic%
And the resulting Al_TwoO_ThreeRetains the crystal structure of
Al_TwoO_Three The main layer has a large ion radius difference.
The normal increase in physical vapor deposition
Al_TwoO_ThreeAlthough the coating layer is affected by the layer thickness, 0.2 to
While having a compressive residual stress of 0.8 GPa, 1.2
圧 縮 3 GPa.
Al with extremely high compressive residual stress_TwoO_ThreeMain layer is above
(Ti, Al) N layer and (Ti, Al) CN layer
Tightly adhered and Al_TwoO_ThreeThe characteristics of
The (Ti, Al) N layer and the
The above-mentioned Al is further added to the surface of the (Ti, Al) CN layer._TwoO_Threemain
Coated carbide cutting tools made by physical vapor deposition of body layers are, for example, steel
Intermittent cutting, especially at high depth of cut with high load on tool cutting edge
Even under heavy cutting conditions such as high feed rate_TwoO_Three
Excellent wear resistance over a long period without peeling of the main layer
To be able to demonstrate their sexuality. (A) and (b)
The research results shown in the above were obtained.

The present invention has been made on the basis of the above research results, and has a surface of a cemented carbide tool substrate having a thickness of 0.1%.
0.5 to 15 μm via an adhesive undercoating layer comprising a single layer or a multilayer of two or more of a TiC layer, a TiN layer, and a TiCN layer having an average layer thickness of 10 to 10 μm.
(Ti, Al) N layer having an average layer thickness of m
In a coated carbide cutting tool obtained by physical vapor deposition of a tough coating layer consisting of one kind of single layer or two or more kinds of i, Al) CN layers, the surface of the toughness coating layer is further resistant to While maintaining the crystal structure of Al ₂ O ₃ as the wearable coating layer, the ratio of a part of Al to the total amount with Al is 0.1%.
01 to 10 atomic% of Ti, Zr, and Hf
Those characterized by a species or formed by substitution solid solution of two or more Al ₂ O ₃ the main layer with an average layer thickness of 0.5~15μm abrasion resistance formed by physical vapor deposition excellent coated cemented carbide cutting tools It is.

The reason why the average thickness of the adhesive undercoat layer, the tough coating layer and the wear-resistant coating layer in the coated carbide cutting tool of the present invention is limited as described above will be described. (A) Adhesive undercoat layer If the average layer thickness is less than 0.1 μm, it is not possible to secure strong adhesion between the carbide tool base and the tough coating layer, while the average layer thickness is 10 μm. If it exceeds the maximum temperature, it causes thermoplastic deformation due to the high heat generated at the time of cutting, causing uneven wear on the cutting edge, and the wear progresses rapidly due to this. It was determined to be 10 μm.

(B) Tough coating layer If the average layer thickness is less than 0.5 μm, the desired excellent toughness cannot be exhibited, and as a result, chipping or chipping (minute chipping) tends to occur in the cutting edge. On the other hand, if the average layer thickness exceeds 15 μm, similar to the above-mentioned adhesive undercoat layer, high heat generated during cutting causes thermoplastic deformation, causing uneven wear on the cutting edge, which causes rapid wear progress. Since the average layer thickness is 0.5 to
It was determined to be 15 μm.

(C) Abrasion-resistant coating layer (Al ₂ O ₃ main layer) If the average layer thickness is less than 0.5 μm, it is not possible to secure desired excellent wear resistance, while the average layer thickness is Fifteen
If the thickness exceeds μm, chipping and chipping of the cutting edge easily occur, so the average layer thickness is set to 0.5 to 15 μm.

[0010] Further, the replacement ratio of Al by Ti, Zr and Hf in the wear-resistant coating layer is set to 0.01.
When the content ratio is less than 0.01 atomic%, the compressive residual stress that can secure sufficient adhesion between the wear-resistant coating layer and the tough coating layer when the content is less than 0.01 atomic%. On the other hand, if the content ratio exceeds 15 atomic%, the compressive residual stress becomes too large and self-destruction is likely to occur. Further, if necessary, TiN may be formed on the wear-resistant coating layer.
The layer may be formed with an average layer thickness of 0.1 to 2 μm, because the TiN layer has a golden shade, which makes it easier to distinguish before and after use of the cutting tool. In this case, if the layer thickness is less than 0.1 μm, the application of the color tone is insufficient, while the application of the color tone is 2 μm.
Average layer thicknesses up to are sufficient.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide cutting tool of the present invention will be specifically described with reference to examples. WC powder having an average particle diameter 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 blended in the composition shown in Table 1, wet-mixed in a ball mill for 72 hours, dried, and pressed into a green compact at a pressure of 1.5 × 10 ⁸ Pa. The green compact is molded in a vacuum at a temperature of 1400.
Sintering under the condition of holding at 1 ° C. for 1 hour.
Carbide tool bases A1 to A8 made of a WC-based cemented carbide having a chip shape of PGA120408 were formed.

In addition, as raw material powders,
TiCN having an average particle size of 2 μm (TiC /
(TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder, Co powder, and Ni powder were prepared, and these raw material powders were blended into the composition shown in Table 2. After wet-mixing with a ball mill for 24 hours and drying, the mixture is pressed into a green compact at a pressure of 9.8 × 10 ⁷ Pa, and the green compact is pressed in a nitrogen atmosphere of 1.3 × 10 ³ Pa at a temperature of: Sintered at 1540 ° C for 1 hour, and after sintering, the cutting edge is subjected to honing of R: 0.03, and a carbide tool made of TiCN-based cermet having a tip shape of ISO standard CNMG120406. Base B1
To B6.

[0013] Then, the carbide tool bases A1 to A8 and B1 to B6 are ultrasonically cleaned in acetone and dried, and each is charged into the arc ion plating apparatus shown in FIG. As an electrode (evaporation source), Ti is used for forming an adhesive undercoat layer, and Ti-Al alloys having various component compositions are used for forming a tough coating layer. 3 × 10 ^-3 Pa
While maintaining the vacuum, the inside of the apparatus was heated to 500 ° C. by a heater, and then an Ar gas was introduced into the apparatus to obtain an Ar atmosphere of 2.5 Pa.
A pulse bias voltage of
r gas bombarding cleaning, and then introducing methane gas and / or nitrogen gas as a reaction gas into the apparatus.
With a reaction atmosphere of 5 Pa, the pulse bias voltage applied to the cemented carbide tool base was reduced to -200 V to generate an arc discharge between the cathode electrode and the anode electrode. A8 and B1
To B6, the conventional coated cemented carbide tool bases 1 to 22 were formed by forming an adhesive base coating layer and a tough coating layer having the target compositions and target layer thicknesses shown in Tables 3 and 4 on each surface.
Was manufactured respectively.

Next, the conventional coated carbide cutting tools 1 to 1
On the surface of each of the electrodes 22, Al— () containing a predetermined amount of one or more of Ti, Zr, and Hf as a cathode electrode (evaporation source) by the arc ion plating apparatus of FIG. While mounting the Ti, Zr, Hf) alloy and evacuating the inside of the apparatus to maintain a vacuum of 1.3 × 10 ⁻³ Pa, the inside of the apparatus is heated to a predetermined temperature within a range of 620 to 720 ° C. by a heater. In this state, the pulse bias voltage applied to the carbide substrate was set to -700 V, and then an arc discharge was generated between the cathode electrode and the anode electrode while introducing oxygen gas as a reaction gas into the apparatus. the present invention coated cemented carbide cutting tools 1 to 22 were prepared respectively by forming a wear-resistant coating layer consisting of a target composition and Al ₂ O ₃ main layers of the target layer thicknesses shown in 5,6. Ti in the Al ₂ O ₃ main layer constituting the wear-resistant coating layer of the coated carbide cutting tools 1-2 of the present invention,
When the contents of Zr and Hf were quantitatively analyzed using an energy dispersive X-ray measuring apparatus, the contents were substantially the same as the target contents in Tables 5 and 6, and the Al ₂ O ₃
When the compressive residual stress of the main layer was measured using the X-ray stress measurement method, the results shown in Tables 5 and 6 were also shown. Furthermore, the composition and layer thickness of the various coating layers were measured by Auger spectroscopy and an optical microscope.
The target composition and the target layer thickness of No. 6 were substantially the same as the target composition and the target layer thickness (average values at five arbitrary locations).

Next, among the coated carbide cutting tools obtained as a result, the coated carbide cutting tools 1 to 16 of the present invention and the conventional coated carbide cutting tools 1 to 16 are described below. Work material: JIS S45C Round bar with four longitudinal grooves at equal intervals in the length direction, Cutting speed: 320 m / min., Feed: 0.3 mm / rev., Depth of cut: 3.2 mm, Cutting time: 10 minutes, dry type of carbon steel Intermittent high-incision cutting test and work material: JIS SNCM440 lengthwise equally spaced round bar with four longitudinal grooves, cutting speed: 280 m / min., Feed: 0.45 mm / rev., Depth of cut: 1. 5mm, cutting time: 10 minutes, dry intermittent high feed cutting test of alloy steel under the following conditions:
For the coated carbide cutting tools 17 to 22 of the present invention and the conventionally coated carbide cutting tools 17 to 22, a work material: JIS SUS304, a longitudinally spaced round bar having four longitudinal grooves, a cutting speed of 280 m / min., feed: 0.3 mm / rev., depth of cut: 3.2 mm, cutting time: 10 minutes, dry intermittent high depth of cut feed cutting test of stainless steel, and work material: length of JIS SNCM439 Round bar with 4 vertical grooves at equal intervals in the length direction, Cutting speed: 320 m / min., Feed: 0.45 mm / rev., Depth of cut: 1.5 mm, Cutting time: 10 min. Perform high-feed cutting test,
In each cutting test, the flank wear width of the cutting edge was measured.
Table 7 shows the measurement results.

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

[Table 3]

[0019]

[Table 4]

[0020]

[Table 5]

[0021]

[Table 6]

[0022]

[Table 7]

[0023]

According to the results shown in Tables 3 to 7, it can be seen that the present invention
The coated carbide cutting tools 1-22 each have a wear-resistant coating layer.
Constituting Al_TwoO_ThreeThe main layer has an ion radius smaller than that of Al.
One or more of significantly larger Ti, Zr, and Hf
Which results in significantly higher compressive residual stress
To form a tough coating layer (T
Strong against (i, Al) N layer and (Ti, Al) CN layer
High-depth intermittent cutting of steel as it comes into firm contact
And Al even under heavy cutting conditions of high feed_TwoO _Threemain
Demonstrates excellent wear resistance without delamination of the body layer
On the other hand, the conventional coated carbide cutting tools 1 to 22
Due to the lack of wear resistance of the tough coating layer,
It is clear that the wear progresses rapidly under severe conditions such as
You. As described above, the coated carbide cutting tool of the present invention has a
Al constituting the wearable coating layer_TwoO_ThreeTangle of main subject
Various conditions under normal conditions due to
Not only continuous and interrupted cutting of steel, but also extremely
High depth of cut and high feed for interrupted cutting which is severe cutting conditions
Even under heavy cutting conditions_TwoO_ThreeOf the main layer
No occurrence, no chipping or chipping of the cutting edge,
Excellent wear resistance and excellent long-term machinability
It is effective for energy saving and saving of cutting process.
It can respond satisfactorily to empowerment.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an arc ion plating apparatus.

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[Procedure amendment]

[Submission date] April 10, 2000 (2004.1.
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

[0010] Further, the replacement ratio of Al by Ti, Zr and Hf in the wear-resistant coating layer is set to 0.01.
When the content ratio is less than 0.01 atomic%, the compressive residual stress that can secure sufficient adhesion between the wear-resistant coating layer and the tough coating layer when the content is less than 0.01 atomic%. On the other hand, if the content exceeds 10 atomic%, the compressive residual stress becomes too large and self-destruction is likely to occur. Further, if necessary, TiN may be formed on the wear-resistant coating layer.
The layer may be formed with an average layer thickness of 0.1 to 2 μm, because the TiN layer has a golden shade, which makes it easier to distinguish before and after use of the cutting tool. In this case, if the layer thickness is less than 0.1 μm, the application of the color tone is insufficient, while the application of the color tone is 2 μm.
Average layer thicknesses up to are sufficient.

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Claims (1)

[Claims] 1. A tool base comprising a tungsten carbide based cemented carbide or a titanium carbonitride based cermet,
A carbide layer of Ti having an average layer thickness of 0.1-10 μm,
0.5 through an adhesive undercoating layer consisting of a single layer or two or more layers of a nitride layer and a carbonitride layer.
Surface coating formed by physical vapor deposition of a tough coating layer comprising a single layer or a double layer of one of a composite nitride layer and a composite carbonitride layer of Ti and Al having an average layer thickness of １５15 μm. In a cemented carbide cutting tool, the surface of the tough coating layer is further treated as a wear-resistant coating layer while maintaining the crystal structure of aluminum oxide.
1 to 0.01 to 10 in a proportion of the total amount with Al
One or more of atomic% of Ti, Zr and Hf
A hard-wearing surface-coated cemented carbide cutting tool having excellent wear resistance, characterized in that an aluminum oxide-based layer formed by substitutional solid solution of at least one kind is physically deposited with an average layer thickness of 0.5 to 15 μm.