JPH1180933A - Cutting tool made of surface coated cemented carbide, excellent in chipping resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool made of surface coated cemented carbide, exhibiting superior wear resistance over a long period and excellent in chipping resistance. SOLUTION: The cutting tool made of surface coated cemented carbide is produced by vapor-depositing, as a first hard coating layer, one or <=2 kinds among metallic Ti layer, titanium nitride layer, and titanium carbonitride layer on the surface of a base material composed of WC-base cemented carbide or TiCN-base cermet to 0.01-2 μm average layer thickness, further vapor-depositing, as a second hard coating layer, either or both of compound nitride layer and compound carbonitride layer of Ti, Al, and Cu, represented by the compositional formulae (Tia Alb Pbc )N and (Tia Alb Cuc )Cd N1-d , respectively, to 2-20 μm layer thickness on the above, and further vapor-depositing, if necessary, a titanium nitride layer as a third hard coating layer to 0.1-1 μm average layer thickness on the above second layer. In the above formulae, the symbols (a), (b), (c), and (d) stand for, by atomic ratio, 0.2-0.6, 0.1-0.79, 0.01-0.3, and 0.01-0.5, respectively, and a+b+c=1 is satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has excellent chipping resistance, so that even when intermittent cutting of steel is performed at high speed, for example, there is no chipping (small chipping) on the cutting edge and excellent wear resistance. Coated cutting tool made of surface-coated cemented carbide (hereinafter referred to as coated cemented carbide tool)
It is about.

[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 the state heated to a temperature of ° C., 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, and at the same time, a nitrogen gas as a reaction gas and Alternatively, nitrogen gas and methane gas are introduced, while tungsten carbide (hereinafter referred to as WC)
A substrate made of a base cemented carbide or titanium carbonitride (hereinafter, referred to as TiCN) -based cermet (hereinafter, collectively referred to as a cemented carbide substrate) is subjected to, for example, a condition in which a bias voltage of -120 V is applied. On the surface of the cemented carbide substrate, as described in, for example, JP-A-62-56565, as a hard coating layer, a composite nitride of Ti and Al [hereinafter, referred to as (Ti, Al) N] layer It is also known to produce coated cemented carbide tools by depositing one or both of the composite carbonitride layers (hereinafter referred to as (Ti, Al) CN) with an average layer thickness of 2 to 20 μm. Have been.

[0003]

On the other hand, in recent years, high performance and high output of cutting equipment have been remarkable, and there is also a demand for labor saving and energy saving of cutting processing. Although there is a tendency, in the case of the above-mentioned conventional coated cemented carbide tools, although excellent wear resistance is exhibited in continuous cutting and interrupted cutting under normal cutting conditions, especially when interrupted cutting of steel etc. is performed at high speed Is likely to cause chipping of the cutting edge due to insufficient toughness of the (Ti, Al) N layer and the (Ti, Al) CN layer constituting the hard coating layer. As a result, the service life is relatively short. It is the current situation.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoints, the (Ti, Al) N layer and the (T) layer constituting the hard coating layer of the conventional coated cemented carbide tool described above.
As a result of studying to improve the toughness of the i, Al) CN layer, a metal Ti layer and a titanium nitride (hereinafter, referred to as Ti) layer were formed on the surface of the cemented carbide substrate as a first hard coating layer.
N) and one or two of the TiCN layers
While depositing more species with an average layer thickness of 0.01 to 2 [mu] m, as the second hard coating layer, the composition _{formula: (Ti a Al b Cu c} ) N, and the composition _{formula: (Ti a Al b Cu c} ) C _d N _1-d , where a: 0.2 to 0.6, b: 0.1
~ 0.79, c: 0.01 ~ 0.3, a + b + c = 1,
d: 0.01 to 0.5), Ti, Al and Cu represented by
[Hereinafter referred to as (Ti, Al, Cu) N]
Layer and composite carbonitride [hereinafter, (Ti, Al, Cu) C
N), the resulting coated cemented carbide tool will have the (Ti, A)
l, Cu) N layer and (Ti, Al, Cu) CN layer
The first hard coating layer has excellent toughness and high hardness in a state where excellent adhesion is maintained between the surface of the cemented carbide substrate and the surface of the cemented carbide substrate. Even if the intermittent cutting is performed at a high speed, a research result has been obtained that chipping does not occur on the cutting edge and excellent wear resistance is exhibited over a long period of time.

The present invention has been made on the basis of the above research results, and includes a metal Ti layer and a titanium nitride (hereinafter, referred to as TiN) as a first hard coating layer on the surface of a cemented carbide substrate.
) Layer shown in, and one or more of the TiCN layer was deposited with an average layer thickness of 0.01 to 2 [mu] m, as the second hard coating layer thereon, a composition formula: (Ti _a Al _b Cu _c) N, and the composition _{formula: (Ti a Al b Cu c} ) C d N 1-d, ( provided that an atomic ratio, a: 0.2~0.6, b: 0.1
~ 0.79, c: 0.01 ~ 0.3, a + b + c = 1,
d: 0.01 to 0.5), Ti, Al and Cu represented by
[Hereinafter referred to as (Ti, Al, Cu) N]
Layer and composite carbonitride [hereinafter, (Ti, Al, Cu) C
N)], and a TiN layer is further deposited thereon, if necessary, as a third hard coating layer with an average layer thickness of 0.1 to 1 μm. The feature is that the coated cemented carbide tool has excellent chipping resistance. Since the TiN layer as the third hard coating layer in the coated cermet tool of the present invention has a golden color tone, it is easy to identify the tool before and after using the tool by vapor deposition.

Next, the composition ratio (atomic ratio) of the (Ti, Al, Cu) N layer and the (Ti, Al, Cu) CN layer constituting the third hard coating layer of the coated cemented carbide tool of the present invention will be described. The reason for limiting as described above will be described. That is, the (Ti, Al, Cu) N layer and the (Ti, Al, Cu)
In the CN layer, the constituent components Ti and Al improve the hardness in a coexisting state, and thus have an action of contributing to the improvement of the wear resistance.
If it is less than 0.2 and Al: less than 0.1, the desired excellent wear resistance cannot be ensured.
If the ratio of any of Al and Al exceeds Ti: 0.6 and Al: 0.79, the toughness decreases and chipping easily occurs on the cutting edge.
0.2-0.6, desirably 0.3-0.5, Al:
0.1 to 0.79, preferably 0.3 to 0.7. Cu, which is also a component, has the effect of improving toughness and thus preventing chipping from occurring on the cutting edge, but if the ratio is less than 0.01, the desired effect of improving toughness cannot be obtained. On the other hand, if the ratio exceeds 0.3, the hardness of the layer itself sharply decreases, and it becomes impossible to secure the excellent wear resistance provided by Ti and Al. 0.3, desirably 0.05 to 0.2. Further, (Ti, Al,
Since the C component in Cu) CN has an effect of improving the hardness, (Ti, Al, Cu) CN has the above (Ti,
Al, Cu) has a relatively high hardness as compared with N, but in this case, if the ratio of the C component is less than 0.01, the predetermined hardness improving effect cannot be obtained, while the ratio is 0.5 If it exceeds, the toughness rapidly decreases, so the ratio of the C component is set to 0.01 to 0.5, preferably 0.1 to 0.45.

The reason why the average thickness of the first to third hard coating layers in the coated cemented carbide tool of the present invention is limited as described above is as follows. That is, the first hard coating layer has an effect of improving the adhesion between the surface of the cemented carbide substrate and the second hard coating layer as described above, but if the average layer thickness is less than 0.01 μm, the first hard coating layer has the effect. If the desired effect cannot be obtained, and if the average layer thickness exceeds 2 μm, the chipping resistance tends to decrease, so the average layer thickness is 0.01 to 2 μm, preferably 0.1 to 1 μm. It was decided. The average thickness of the second hard coating layer is 2 to 20 μm.
The reason why m is used is that if the layer thickness is less than 2 μm, the desired effect of improving wear resistance cannot be obtained, while if the layer thickness exceeds 20 μm, chipping is likely to occur on the cutting edge, and this is desirable. Is preferably an average layer thickness of 3 to 10 μm. Further, the average thickness of the TiN layer, which is the third hard coating layer, is 0.1 to 1 μm because the thickness is 0.1 μm.
If it is less than 10, a clear golden color cannot be imparted, while the desired golden color is because a layer thickness of up to 1 μm is sufficient.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the coated cemented carbide tool of the present invention will be specifically described with reference to examples. WC powder and Co powder each having an average particle diameter of 0.7 to 2 μm are prepared as raw material powders,
WC: 94%, Co: 6%, wet-mixed in a ball mill for 72 hours, dried, 1.5 to
The green compact is press-molded at a pressure of n / cm ² , and the green compact is sintered in vacuum at a temperature of 1380 ° C. for 1 hour, and after sintering, R: 0. Honing process No. 05 was performed to form a cemented carbide substrate A made of a WC-based cemented carbide having a chip shape of ISO standard WNMG080408. As raw material powder, TiCN having an average particle diameter of 0.5 to 2 μm [by weight, TiC / TiN
= 50/50] powder, TiN powder, TaC powder, NbC
Powder, Mo powder, Co powder, Ni powder, and graphite (C) powder are prepared, and these raw material powders are expressed in T
iCN: 77%, TiN: 4%, TaC: 4%, Nb
C: 2%, Mo: 1%, Co: 5%, Ni: 6%, and C: 1% were blended into a composition, wet-mixed with a ball mill for 24 hours, dried, and then subjected to a pressure of 1 ton / cm ² . Is pressed into a green compact, and the green compact is sintered in a nitrogen atmosphere of 15 torr at a temperature of 1560 ° C. for 1 hour, and after sintering, the cutting edge portion is honed with R: 0.05. Processing was performed to form a cemented carbide substrate B made of a TiCN-based cermet having a chip shape conforming to ISO standard, CNMG120408.

Next, these cemented carbide substrates A and B, after being ultrasonically cleaned in acetone, are loaded into the arc ion plating apparatus shown in FIG. 1, respectively, while various types are used as cathode electrodes (evaporation sources). T with the composition of
An i-Al-Cu alloy, a Ti-Al alloy, and a metal Ti were mounted, and the inside of the apparatus was evacuated to 1 × 10 ⁻⁵ t.
While maintaining a vacuum of orr, 35
After heating to 0 ° C., a bias voltage of −40 V was applied to the cemented carbide substrate, and nitrogen gas or nitrogen gas and methane gas were introduced as a reaction gas into the apparatus, and a gas was supplied between the cathode electrode and the anode electrode. Causing arc discharge,
By forming a hard coating layer having the composition and the average layer thickness shown in Tables 1 to 4 on each surface of the cemented carbide substrates A and B, the coated cemented carbide tools 1 to 1 of the present invention are formed.
8 and conventional coated cemented carbide tools 1 to 4, respectively.

[0010] Of the various coated cemented carbide tools obtained as a result, the coated cemented carbide tools 1 to 9 of the present invention and the conventional coated cemented carbide tools 1 and 2 are as follows: Work material: JIS SCM435 Round bar with four vertical grooves at equal intervals in the vertical direction, Cutting speed: 260 m / min, Feed: 0.2 mm / rev, Cutting depth: 1.5 mm, Cutting time: 10 minutes, Dry high-speed intermittent cutting test of alloy steel Also, for the coated cemented carbide tools 10 to 18 of the present invention and the conventionally coated cemented carbide tools 3 and 4, the work material: JIS SNCM240C 4
A dry high-speed interrupted cutting test of an alloy steel was performed under the following conditions: a round bar with this vertical groove, cutting speed: 250 m / min, feed: 0.3 mm / rev, cutting depth: 1.5 mm, cutting time: 10 minutes. The flank wear width of the cutting edge was also measured in the cutting test. Table 5 shows the results of these measurements.

[0011]

[Table 1]

[0012]

[Table 2]

[0013]

[Table 3]

[0014]

[Table 4]

[0015]

[Table 5]

[0016]

From the results shown in Tables 1 to 5, all of the coated cemented carbide tools 1 to 18 of the present invention show excellent wear resistance in high-speed interrupted cutting of steel, and the wear condition of the cutting edge is also reduced. In contrast to the normal condition, the conventional coated cemented carbide tools 1 to 4 cause chipping on the cutting edge, especially in high-speed interrupted cutting of steel due to insufficient toughness of the second hard coating layer. It is clear that the service life can be reached in a short time. As described above, the coated cemented carbide tool according to the present invention has the above-mentioned (Ti, Al, Cu) N and (T
Since i, Al, Cu) CN has excellent toughness and high hardness, chipping is applied to the cutting edge in high-speed continuous cutting of steel as well as high-speed intermittent cutting of steel, which is a cutting process under more severe conditions. It exhibits excellent wear resistance over an extremely long period without occurrence of cracks.

[Brief description of the drawings]

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

Claims (2)

[Claims] A first hard coating layer on a surface of a tungsten carbide-based cemented carbide substrate or a titanium carbonitride-based cermet substrate, one or more of a metal Ti layer, a titanium nitride layer, and a titanium carbonitride layer. 0 or more seeds.
Deposited with an average layer thickness of 01～2Myuemu, the second hard coating layer thereon, a composition _{formula: (Ti a Al b Cu c} ) N, and the composition _{formula: (Ti a Al b Cu c} ) C d N 1 _-d , (However, in atomic ratio, a: 0.2 to 0.6, b: 0.1
~ 0.79, c: 0.01 ~ 0.3, a + b + c = 1,
d: 0.01 to 0.5), Ti, Al and Cu represented by
A cutting tool made of a surface-coated cemented carbide having excellent chipping resistance, wherein one or both of the composite nitride layer and the composite carbonitride layer are deposited with an average layer thickness of 2 to 20 μm. 2. A surface of a tungsten carbide-based cemented carbide substrate or a titanium carbonitride-based cermet substrate, as a first hard coating layer, one or two of a metal Ti layer, a titanium nitride layer, and a titanium carbonitride layer. 0 or more seeds.
Deposited with an average layer thickness of 01～2Myuemu, the second hard coating layer thereon, a composition _{formula: (Ti a Al b Cu c} ) N, and the composition _{formula: (Ti a Al b Cu c} ) C d N 1 _-d , (However, in atomic ratio, a: 0.2 to 0.6, b: 0.1
~ 0.79, c: 0.01 ~ 0.3, a + b + c = 1,
d: 0.01 to 0.5), Ti, Al and Cu represented by
Either or both of the composite nitride layer and the composite carbonitride layer are deposited with an average layer thickness of 2 to 20 μm, and a titanium nitride layer is further formed thereon as a third hard coating layer by 0.1 μm. A cutting tool made of a surface-coated cemented carbide with excellent chipping resistance, which is deposited with an average layer thickness of １1 μm.