JP2000246506A - Cutting tool made of surface coated super head material exhibiting excellent high temperature heat conductivity at its hard coated layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool made of surface coated super hard material exhibiting excellent high temperature heat conductivity at its hard coated layer. SOLUTION: In this cutting tool made out of surface coated super hard material, the surface of a substrate composed of a WC group super hard alloy or cermet in a TiCN system is provided with (a) a Ti compound layer having average layer thickness 0.1 to 5 μm, composed of one or more than two layers out of a titanium carbide layer, a titanium nitride layer, and titanium carbide and nitride layer, and satisfying that v is 0.8 to 1.2, and w is 0.3 to 0.7 in terms of an atomic ratio when respective composition formulae are represented by TiCv, TiNr and Ti(C1-w, Nw)v, and with (b) a composite oxide layer having average layer thickness 0.1 to 10 μm, and satisfying that x is 0.01 to 0.3, and y is 1 to 2 in terms of an atomic, when its composition formula is represented by (Al1-xMx)Oy (where, M indicates a metallic constituent composed of one or more than two kinds out of V, Nb, Ta, Cr and Y). A hard coated layer formed of (a) and (b) is physically deposited so as to be 0.5 to 20 μm in the whole average layer thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is particularly applicable to high-speed cutting in which a hard coating layer exhibits excellent high-temperature thermal conductivity in a cutting process involving high heat generation, and thus, for example, a cutting edge is exposed to high temperatures. Also, the present invention relates to a cutting tool made of a surface-coated cemented carbide material (hereinafter referred to as a coated cemented carbide tool) which suppresses the progress of wear of the cutting blade and exhibits excellent wear resistance over a long period of time.

[0002]

2. Description of the Related Art Conventionally, for example, an arc ion plating apparatus, which is a kind of a physical vapor deposition apparatus schematically shown in FIG. 1, is used, and the inside of the apparatus is heated to a temperature of, for example, 400.degree. An arc discharge is generated between the electrode and a cathode electrode (evaporation source) on which metal Ti or metal Al is set, and at the same time, as a reaction gas in the apparatus,
When the metal Ti is set on the cathode electrode, methane gas, nitrogen gas, or nitrogen gas and methane gas are introduced, and when the metal Al is set, oxygen gas is introduced. , WC) based cemented carbide or titanium carbonitride (hereinafter TiCN)
A substrate made of a cermet (shown below) (hereinafter collectively referred to as a super hard substrate) is applied to a surface of the super hard substrate under the condition that a bias voltage of -70 V is applied, for example.
(A) All have an average layer thickness of 0.1 to 5 μm, and each has a composition formula: TiC _v , TiN _v , and Ti (C
If you were expressed in _{1-w N w) v,} v in atomic ratio: 0.8.
2, w: one or two of a titanium carbide layer, a titanium nitride layer, and a titanium carbonitride layer satisfying 0.3 to 0.7.
(B) 0.1 to 10 μm
An aluminum oxide layer (hereinafter, referred to as an AlO _y layer) satisfying an atomic ratio y: 1-2 when represented by the composition formula: AlO _y , 0.5 to 20 μm of the hard coating layer constituted by (b)
It has been attempted to produce a coated cemented carbide tool obtained by physical vapor deposition with an overall average layer thickness of, and research for practical use has been conducted.

[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 above-mentioned conventional coated cemented carbide tool, when this is used for high-speed cutting accompanied by high heat generation, especially when the hard coating layer is formed of AlO _y
When the layer is exposed to high temperatures, the thermal conductivity drops sharply, which inevitably increases the temperature of the cutting edge, which promotes abrasion and leads to a relatively short service life. is the current situation.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoints, we focused on the AlO _y layer that constitutes the hard coating layer of the above-mentioned conventional coated carbide tool, and without deteriorating its excellent heat resistance and high strength, it has excellent high-temperature heat conduction. As a result of a study for imparting the property, a part of Al in the AlO _y layer constituting the hard coating layer of the conventional coated carbide tool was 0.01 to 0 in an atomic ratio occupying the total amount with Al. V, Nb, Ta,
Substitution with a metal component consisting of one or more of Cr and Y results in a composite oxide layer of Al and the metal component, that is, a composition formula: (Al _1−x M _x ) O _y (Where M is the above V, Nb, Ta, Cr, and Y
Metal component comprising one or more of the above), x: 0.01 to 0.3 and y: 1 to 2 in atomic ratio.
A composite oxide layer of Al and the above metal component satisfying
The composite oxide layer) exhibits excellent high-temperature thermal conductivity without deteriorating the thermal conductivity even at high temperatures. Therefore, this composite oxide layer is hardened together with the Ti compound layer. The coated cemented carbide tool that constitutes the coating layer, the composite oxide layer exhibits excellent high-temperature thermal conductivity due to the action of the above-described metal component even when this is used for high-speed cutting of steel or the like with high heat generation. Therefore, the research result that the wear progress of the cutting blade is suppressed and excellent wear resistance is exhibited over a long period of time was obtained.

The present invention has been made on the basis of the above research results, and (a) all have an average layer thickness of 0.1 to 5 μm on the surface of a cemented carbide substrate, and each has a composition formula : TiC _v , TiN _v , and Ti (C _1-w N _w ) _v
When expressed in terms of atomic ratios, v: 0.8 to 1.2, w: 0.
A Ti compound layer comprising one or more of a titanium carbide layer, a titanium nitride layer, and a titanium carbonitride layer satisfying 3 to 0.7;
1 to 10 μm and a composition formula: (Al _1−x M _x ) O _y (where M is a metal component composed of one or more of V, Nb, Ta, Cr, and Y) ), X: 0.01-0.3, y: 1-2 in atomic ratio.
A high-temperature thermal conductivity excellent in a hard coating layer obtained by physical vapor-depositing a complex oxide layer satisfying the above condition, and a hard coating layer composed of the above (a) and (b) with a total average layer thickness of 0.5 to 20 μm. It is characterized by a coated carbide tool that exerts its properties.

Next, the reason why the composition formula and the average layer thickness of the Ti compound layer and the composite oxide layer constituting the hard coating layer in the coated carbide tool of the present invention are limited as described above will be described. (A) Ti compound layer Each of the Ti compound layers has a lower hardness but a higher toughness as compared with the composite oxide layer which is the same constituent layer, and thus the hard coating layer has a predetermined toughness. In this way, it exerts the effect of suppressing the occurrence of chipping or chipping (small chipping) in the cutting edge during practical use, and has a relative hardness of titanium nitride layer, titanium carbonitride layer, and If the average thickness is less than 0.1 μm, the desired effect cannot be obtained in the above-described operation. On the other hand, if the average thickness is up to 5 μm, the effect is sufficient. Is unnecessary, the average layer thickness is determined to be 0.1 to 5 μm. In addition, each Ti
When the value of v in the compound layer is less than 0.8, the layer itself becomes too soft and the abrasion resistance is significantly reduced,
On the other hand, if the value exceeds 1.2, the layer becomes brittle and causes the occurrence of defects.
It is defined as 2. Further, the w-value of the titanium carbonitride layer is less than 0.3, and if it exceeds 0.7, the intermediate property between the titanium nitride layer and the titanium carbide layer cannot be maintained. Is set to 0.3 to 0.7.

[0007] (b) a composite oxide layer of the composite oxide layer also hard layer has excellent heat resistance and high strength of the street AlO _y, further holds the high hardness, it is heated to a high temperature Even if it does, there is no decrease in thermal conductivity, maintaining excellent high-temperature thermal conductivity,
Thus, it exerts the effect of suppressing the decrease in wear resistance during high heat cutting, but the x value indicating the ratio of the metal component to the total amount of Al in the composition formula was set to 0.01 to 0.3 in atomic ratio. If the value of x is less than 0.01, the desired improvement effect on the high-temperature thermal conductivity of the composite oxide layer cannot be obtained, while if the value of x exceeds 0.3, the hardness particularly decreases rapidly, This is because it is not possible to maintain the desired excellent wear resistance, and the x value is preferably 0.05 to 0.25. Further, the reason why the y value in the composite oxide layer is determined to be 1 to 2 in atomic ratio is that if the y value is less than 1, the ratio of oxygen to Al is relatively too small, so that the desired excellent heat resistance and High strength and high hardness cannot be ensured. On the other hand, when the y value exceeds 2, the layer itself is rapidly embrittled,
This is based on the reason that this causes the occurrence of defects. Further, the average thickness of the composite oxide layer is 0.1
If the layer thickness is less than 0.1 μm, the desired excellent wear resistance cannot be secured,
On the other hand, if the layer thickness exceeds 10 μm, chipping is likely to occur on the cutting edge.
The thickness is preferably 2 to 5 μm.

In addition, the total average layer thickness of the hard coating layer is 0.5
When the thickness is less than 0.5 μm, the desired effect cannot be obtained on the improvement of abrasion resistance by the hard coating layer when the thickness is less than 0.5 μm, while when the thickness exceeds 20 μm, chipping easily occurs on the cutting edge. For this reason, the average layer thickness is desirably 3 to 10 μm.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide tool of the present invention will be specifically described with reference to examples. As raw material powders, WC powder, TiC powder, TaC powder, and Co powder each having an average particle diameter of 0.5 to 3.5 μm are prepared, and these raw material powders are WC: 90% by weight, Ti
C: 1%, TaC: 1%, and Co: 8% were blended into a composition, wet-mixed in a ball mill for 72 hours, and dried.
Press molding into a green compact at a pressure of 1.5 ton / cm ² ,
This green compact is sintered in a vacuum at a temperature of 1450 ° C. for 1 hour, and after sintering, the cutting edge portion is subjected to a honing process of R: 0.03 to obtain an ISO standard SEKN1203AF.
A cemented carbide substrate A made of a WC-based cemented carbide having a chip shape of EN1 was formed. In addition, as raw material powders, in each case, 0.1.
TiCN having an average particle size of 5-2 μm [by weight, T
iC / TiN = 50/50] powder, TaC powder, WC powder, VC powder, Co powder, Ni powder, and graphite (C)
Powders are prepared, and these raw material powders are converted to TiC by weight%.
N: 74.5%, TaC: 3%, WC: 9.5%, V
C: 1%, Co: 8%, Ni: 3%, C: 1% are blended, wet-mixed by a ball mill for 24 hours, dried, and pressed into a green compact at a pressure of 1 ton / cm ^2. The green compact was molded in a nitrogen atmosphere of 5 torr at a temperature of 1: 1.
After sintering under the condition of holding at 500 ° C. for 1 hour, after sintering, the cutting edge is subjected to a honing process of R: 0.03 to obtain a tip having a tip shape of ISO standard SEEN1203AFEN1.
A carbide substrate B made of iCN-based cermet was formed.

Next, these super-hard substrates A and B are subjected to ultrasonic cleaning in acetone and dried, and then loaded into the arc ion plating apparatus shown in FIG. 1, respectively. Al-M alloys having various component compositions, metal Ti, and metal Al were mounted, and the inside of the apparatus was evacuated and maintained at a vacuum of 1 × 10 ^-5 torr while the inside of the apparatus was heated to 300 ° C. with a heater. Then, a bias voltage of −100 V is applied to the cemented carbide substrate, and the cathode electrode is made of metal Ti as a reaction gas in the apparatus.
When forming a Ti compound layer as, methane gas,
While introducing a nitrogen gas or a nitrogen gas and a methane gas, and introducing an oxygen gas when forming a composite oxide layer or an AlO _y layer using an Al-M alloy or metal Al as a cathode electrode, the cathode electrode and the anode are introduced. An arc discharge is generated between the electrode and the electrode, and the composition shown in Tables 1 to 4 (measured with a scanning electron microscope, the values in the table are measured at five places) on the surfaces of the cemented carbide substrates A and B. By physical vapor deposition of a hard coating layer having an average layer thickness) and a hard coating layer of the present invention, in which the hard coating layer is composed of a Ti compound layer and a composite oxide layer, and Comparative coated carbide tools 1 to 4 in which the hard coating layer was composed of a Ti compound layer and an AlO _y layer were manufactured respectively.

[0011] Of the various coated cemented carbide tools obtained as a result, the coated cemented carbide tools 1 to 11 of the present invention and the conventionally coated cemented carbide tools 1 and 2 are as follows: Work material: JIS SCM440 (hardness: HR C30) round bar, cutting speed: 400 m / min, feed: 0.2 mm / rev, depth of cut: 1.0 mm, cutting time: 20 minutes, dry continuous high-speed cutting test of alloy steel under the following conditions: Cutting material: Square bar of JIS SKD61 (hardness: HR C55), Cutting speed: 250 m / min, Feed: 0.3 mm / rev, Cutting depth: 1.5 mm, Cutting time: 10 minutes, Hardened steel Of the present invention coated carbide tools 12 to 20 and comparative coated carbide tools 3 and 4 were subjected to a work material: JIS SNCM439 (hardness: HR C30).
Round bar, cutting speed: 380 m / min, feed: 0.15 mm / rev, cutting depth: 0.8 mm, cutting time: 20 minutes, dry continuous high-speed cutting test of alloy steel under the following conditions: JIS SKD11 (hardness: HR C60) square material, cutting speed: 300 m / min, feed: 0.3 mm / rev, cutting depth: 1.5 mm, cutting time: 10 minutes, dry high-speed hardened steel under the following conditions: An intermittent cutting test was performed, and the flank wear width of the cutting edge was measured in each cutting test. The measurement results are shown in Tables 2 and 4.

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

[Table 3]

[0015]

[Table 4]

[0016]

From the results shown in Tables 1 to 4, all of the coated carbide tools 1 to 20 of the present invention can be made of a high-hardness steel whose cutting edge is heated at a high temperature by the composite oxide layer constituting the hard coating layer. In cutting, the reduction of the thermal conductivity of the hard coating layer is suppressed, and since the overheating of the cutting edge is prevented, it shows excellent wear resistance, and the wear condition of the cutting blade is also normal, In the comparative coated carbide tools 1 to 4, it is apparent that the thermal conductivity of the AlO _y layer constituting the hard coating layer particularly deteriorates significantly at a high temperature, which promotes the wear progress of the cutting edge. . As described above, the coated cemented carbide tool of the present invention has excellent wear resistance not only in continuous cutting and interrupted cutting under normal conditions of steel, but also in high-speed cutting where heat generation is high and heating of the cutting edge is remarkable. And exhibit excellent cutting performance over a long period of time.

[Brief description of the drawings]

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

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Claims (1)

[Claims] 1. A surface of a tungsten carbide-based cemented carbide substrate or a titanium carbonitride-based cermet substrate, wherein (a) each has an average layer thickness of 0.1 to 5 μm, and each has a composition formula: TiC _v , TiN _v , and Ti (C
If you were expressed in _{1-w N w) v,} v in atomic ratio: 0.8.
2, w: one or two of a titanium carbide layer, a titanium nitride layer, and a titanium carbonitride layer satisfying 0.3 to 0.7.
And (b) each having an average layer thickness of 0.1 to 10 μm, and a composition formula: (Al _1−x M _x ) O _y (where M is V, Nb , Ta, Cr, and Y, a metal component comprising one or more of the following): x: 0.01-0.3, y: 1-2 in atomic ratio
The composite oxide layer of Al and the above metal component satisfying the above condition, and the hard coating layer composed of the above (a) and (b) is 0.5 to
A cutting tool made of a surface-coated cemented carbide material having a hard coating layer exhibiting excellent high-temperature thermal conductivity, which is formed by physical vapor deposition with an overall average layer thickness of 20 μm.