JP2000308906A - Heat resisting hard coating covered tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat resisting hard coating covered tool provided with a hard coating having further excellent heat resistance and oxidation resistance and with excellent wear resistance in high hardness. SOLUTION: This heat resisting hard coating covered tool 10 is provided with a base material 12 made of, for instance, cemented carbide alloy (equivalent product to JISZ10 mainly composed of WC-10Co) and a heat resisting hard coating 14 secured onto a surface of this base material 12. By constituting the material of this heat resisting hard coating 14 from (TixAl1-x-y (SiC)y)N (however, 0.3<=x<=0.7, 0.02<=y<=0.2), the material is excellent in heat resistance, oxidation resistance and wear resistance provided with high hardness, so as to obtain the heat resisting hard coating covered tool 10 excellent in heat resistance, oxidation resistance and wear resistance in high hardness even in high temperature cutting such as dry cutting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool coated with a heat-resistant hard coating on a surface of a tool made of a high speed tool steel, a cemented carbide, a cermet or a CBN sintered body as a base material. It is about.

[0002]

2. Description of the Related Art Cutting tools such as end mills, drills, taps, and throw-away inserts for milling, which use high-speed steel, cemented carbide, cermet, ceramics, etc. as a base material, have improved heat resistance and wear resistance. Therefore, a coating tool coated with a ceramic hard coating such as TiN, TiCN, or TiAlN by a physical vapor deposition method (PVD method) has come to be used frequently. The PVD method is widely used for coating high-speed steel tools because the film formation temperature is as low as 500 ° C. In addition, the throw-away tip also uses a chemical vapor deposition method (CVD method) as in the past.
A reaction layer is formed at the interface between the coating and the base material, and the strength of the base material is reduced. On the other hand, the reaction layer is not formed by the PVD method, so the strength of the base material is not reduced, and the cutting edge is chipped. The rate of application is increasing rapidly.

[0003] In recent years, interest in environmental protection has increased, and in the field of cutting, in order to reduce the amount of cutting oil discharged as industrial waste, dry cutting has been rapidly shifted. In addition, the demand for high-speed cutting and high-hardness material cutting is also increasing, and cutting tools are increasingly required to have high heat resistance and wear resistance.

At present, the most widely used TiN and T
In tools with iCN coating, oxidation resistance and heat resistance are not yet sufficient in high-temperature cutting such as dry cutting as described above, and rapid wear occurs due to oxidation of the coating and a decrease in hardness, resulting in tool wear. There was a problem that the cutting life was shortened. For this reason, in recent years, a (Ti, Al) N film having excellent oxidation resistance and a high film hardness has been proposed and has begun to be widely used mainly in cemented carbide cutting tools. In the field of cutting, such (Ti, A
1) There remains a problem that sufficient heat resistance and hardness cannot be obtained even with an N film.

[0005]

On the other hand, a (Ti, Al, V) N coating and a (Ti, Al, Si) CN coating have been proposed as hard coatings having better heat resistance.
For example, Japanese Patent Publication No. Hei 5-88309 and Japanese Unexamined Patent Publication No.
That is the hard coating described in JP 09336.
However, the (Ti, Al, V) N film and the (Ti, Al, Cr) N film described above have a drawback that the oxidation resistance of the film decreases as the added element increases. In order to improve the oxidation resistance, (Ti, Al, Si) N in which the element V or Cr in the coating is replaced by Si.
Although a coating has been proposed, there is a drawback that the oxidation resistance is improved to some extent but is not sufficient.

The present invention has been made in view of the above circumstances, and has as its object to provide a hard coating having excellent heat resistance and oxidation resistance, high hardness and excellent wear resistance. To provide a heat-resistant hard coating tool.

[0007]

The present inventors have proposed (Ti,
As a result of repeated studies of adding various elements and compounds based on (Ti, Al) N for the purpose of further improving the heat resistance of the Al) N film, it is considered that the addition is considered to be effective in improving the heat resistance. While studying the elements and compounds, it was found that when silicon carbide SiC was added to (Ti, Al) N, the hardness was high and the oxidation start temperature was high. Generally, the oxidation resistance of (Ti, Al) N is T
Better than iN, but oxidizes rapidly at high temperatures above 800 ° C. It is known that the cause of rapid oxidation is that the growth of TiO _{2 in} the coating film is significantly faster than the growth of Al ₂ O _{3 having} excellent oxidation resistance. Since the basic growth mechanism (growth mechanism) of TiO ₂ is considered to be diffusion of oxygen through oxygen vacancies therein, the addition of SiC as in the present invention results in oxygen vacancies in TiO _2. It is considered that the concentration decreased, the growth rate was slowed, and Al ₂ O ₃ was easily formed, and as a result, the oxidation resistance was improved. The present invention has been made based on such findings.

That is, the gist of the present invention is as follows.
(Ti _x Al _1-xy SiC _y ) N (however, 0.3 ≦ x ≦
(0.7, 0.02 ≦ y ≦ 0.2) The heat-resistant hard coating represented by the composition of (0.7, 0.02 ≦ y ≦ 0.2) was formed on the surface of the substrate of the tool coated with the heat-resistant hard coating.

[0009]

In this manner, the heat-resistant hard coating is (T
_{i x Al 1-xy SiC y} ) N ( where, 0.3 ≦ x ≦ 0.
7, 0.02 ≦ y ≦ 0.2), which is a tool coated with a heat-resistant hard coating having a hard coating having excellent heat resistance and oxidation resistance, high hardness and excellent wear resistance. Is obtained. Therefore, the tool coated with a heat-resistant hard film has excellent heat resistance, oxidation resistance, high hardness and excellent wear resistance even in high-temperature cutting such as dry cutting.

[0010]

In another preferred embodiment of the present invention, the heat-resistant hard coating formed on the substrate surface of the heat-resistant hard coating-coated tool is preferably
Thickness in the range of 0.1 to 10 μm, more preferably 1 to
It has a thickness in the range of 8 μm. In this case, the wear resistance can be reliably obtained, and at the same time, the adhesive strength of the heat-resistant hard coating to the surface of the base material can be sufficiently obtained. When the thickness of the heat-resistant hard coating is less than 0.1 μm, the effect of providing the heat-resistant hard coating, that is, the heat-resistant abrasion resistance cannot be sufficiently obtained. As a result, cracks and the like are generated in the heat-resistant hard coating, and chipping easily occurs. In particular, when the heat-resistant hard film is constituted by one layer, the thickness is preferably in the range of 1 to 8 μm for the same reason as described above.

Preferably, the (Ti _x Al _{1 -xy)}
(SiC) _y ) N (where 0.3 ≦ x ≦ 0.7, 0.0
2 ≦ y ≦ 0.2) In the heat-resistant hard coating, the T
i, the ratio y to Al, that is, the added amount y of SiC
Is in the range of 2 to 20 at% (atomic percent). If the amount is less than 2 at%, the effect of adding SiC, that is, the oxidation resistance, cannot be sufficiently obtained. If the amount exceeds 20 at%, the adhesion strength of the heat-resistant hard coating to the substrate surface decreases.

Preferably, the heat-resistant hard coating is fixed to the surface of the base material by an arc discharge ion plating method using a target formed from titanium powder, aluminum powder, and SiC powder. is there. Generally, when aluminum Al and titanium Ti as evaporating substances are ion-plated by flying them toward the substrate surface in an ionized state, for example, in an ion plating method using a hollow cathode, Ti, Al and SiC are mixed. Al having a relatively low melting point (melting point of about 660 ° C.) tends to be scattered in a larger amount than Ti having a relatively high melting point (melting point of about 1675 ° C.) due to dissolution. However, as described above, in arc discharge ion plating using a target formed by hot pressing or the like from titanium powder, aluminum powder, and SiC powder as a cathode (evaporator), the arc of the target is Since the hit part (arc spot) is skipped, the structure of the target is There is an advantage that heat hard coating ingredients and substantially the same components are affixed to the substrate surface. That is,
In a study by the present inventors for the purpose of further improving the heat resistance of (Ti, Al) N, an arc discharge ion plating method using a target formed from titanium powder, aluminum powder, and SiC powder was used. When a hard coating is provided on the surface of a tool base material, SiC is contained in the hard coating at a value substantially equal to the component ratio (component concentration) constituting the target, and excellent heat resistance, oxidation resistance, and It has been found that a heat-resistant hard coating having wear resistance can be easily obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an enlarged sectional view of an essential part for explaining an example of a heat-resistant hard coating tool 10 according to one embodiment of the present invention. The heat-resistant hard film-coated tool 10 is a cutting tool such as a milling cutter, an end mill, a tap, and a die. The heat-resistant hard film-coated tool 10 includes, for example, a base material 12 made of a cemented carbide (equivalent to JISZ10 containing WC-10Co as a main component) and a heat-resistant hard film 14 fixed on the surface of the base material 12. ing. The material of the heat-resistant hard coating _{14, (Ti x Al 1-xy} (SiC) y) N
(However, 0.3 ≦ x ≦ 0.7, 0.02 ≦ y ≦ 0.2)
By being composed of, since it has excellent heat resistance and oxidation resistance, and has excellent wear resistance with high hardness,
Even in high-temperature cutting such as dry cutting, the heat-resistant hard film-coated tool 10 is excellent in heat resistance and oxidation resistance, and has high hardness and excellent wear resistance.

[0014] The _{(Ti x Al 1-xy (} SiC) y) N
The heat-resistant hard coating 14 having a thickness in the range of 0.1 to 10 μm, more preferably a thickness in the range of 1 to 8 μm. In addition, sufficient adhesion strength of the heat-resistant hard coating to the surface of the substrate 12 can be obtained. In the heat-resistant hard coating 14, the ratio y of SiC to Ti and Al, that is, the added amount (content) y of SiC is 2 to 20.
At% (atomic percentage), and the addition amount (content) x of Ti is within a range of 30 to 70 at%. As a result, the oxidation resistance and the film adhesion strength of the heat-resistant hard coating 14 related to the SiC content y and the toughness and oxidation resistance of the heat-resistant hard coating 14 related to the Ti content x are made compatible.

The tool 10 coated with a heat-resistant hard coating is manufactured, for example, through the steps described below. First, the base material 12 formed into a basic shape as a cutting tool by grinding or the like is made of titanium powder, aluminum powder, and S powder.
It is fixed to a substrate holder of an arc discharge ion plating apparatus using a target (cathode or cathode electrode) formed from iC powder by hot pressing or the like. The substrate holder is rotatably provided and is heated by a heater provided for heating the substrate. Next, the inside of the chamber accommodating the substrate holder and the target is, for example, 6.70 × 10 ⁻³ Pa
And the temperature of the substrate 12 is reduced to 5 by the heater.
Heat to 00 ° C. Thereafter, an end mill potential of about -1000V is applied, after which the arc discharge is started the surface of the substrate 12 is sufficiently cleaned, the N ₂ gas with potential is dropped to about -200V of 1000 cc / min Flowed into the champers at a ratio. In such a plating step, an arc is blown to the target, and a portion (arcsport) of the target which is struck by the arc is vaporized and ionized and is blown toward the base material 12. A heat-resistant hard coating 14 made of the same material as the constituent material of the target, for example, 0.1
Thickness in the range of 10 to 10 μm, more preferably 1 to 8 μm
The thickness is fixed within the range.

FIG. 2 shows the above (Ti _x Al _1-xy (Si
C) shows the result of an experiment in which the relationship between the value y of SiC contained in the heat-resistant hard coating 14 made of _y ) N, that is, the content at% (atomic percent), and the oxidation resistance is shown. In this experimental example, the addition amount (at%) of SiC was set to 0, 1 by Ti: Al = 1: 1 (atomic ratio, at ratio) by ion plating on a cemented carbide substrate of JIS Z10. Six types of heat-resistant hard films 14 of 2, 10, 20, and 30 were formed with a bias voltage of -200 V, a nitrogen flow rate into the chamber of 1000 cc / min, and a film thickness of 3.5 to 3.8 μm. Were prepared, and the oxidation onset temperatures of these six types of samples were determined using the following oxidation test conditions. In this oxidation test, a thermogravimetric analyzer was used, and the temperature at which the occurrence of weight change of the sample was determined under the following test conditions was determined as the oxidation start temperature of the sample.

(Oxidation test conditions) Temperature range: room temperature to 1400 ° C. Temperature rising rate: 10 ° C./min Atmosphere: air

According to the experimental results shown in FIG. 2, the oxidation start temperature rises when the addition amount of SiC in the heat-resistant hard coating 14 exceeds 0.1 at%, and when the addition amount exceeds 2 at%, the oxidation start temperature increases. Compared to the case where the addition amount is zero,
The temperature rose by about 100 ° C. Further, the added amount of SiC is set to 10a.
When it is increased to t%, the oxidation start temperature is 1190 ° C.,
When the addition amount of SiC was increased to 20 at%, the oxidation start temperature was 1240 ° C., and the addition amount was 20 at%.
When the temperature further increased, the oxidation start temperature tended to be saturated. That is, if the amount of SiC added to the heat-resistant hard coating 14 is less than 2.0 at%, the effect of including SiC is not sufficiently recognized, and if it exceeds 20 at%, the effect of adding SiC is saturated.

FIG. 3 shows the (Ti _x Al _1-xy (Si
C) shows the results of an experiment in which the relationship between the value y of SiC contained in the heat-resistant hard coating 14 made of _y ) N, that is, the content at% (atomic percent), and the coating adhesion strength (N) is obtained. In this experimental example, JIS Z
On a cemented carbide substrate of No. 10, the addition amount (at%) of SiC was set to 0, 1, 2, 10, 20 by Ti: Al = 1: 1 (atomic ratio, at ratio) by ion plating. , 30 with a bias voltage of -200 V and a nitrogen flow rate of 1000 cc / min into the chamber.
In this example, six kinds of samples having a film thickness of 3.5 to 3.8 μm were prepared, and the film adhesion strengths of the six kinds of samples were measured. This film adhesion strength, Swiss CS
The measurement was performed using an automatic scratch tester equipped with a sensor for measuring the film adhesion strength manufactured by EM.

According to the experimental results shown in FIG.
The added amount of SiC in the film 14 exceeds 0.1 at%.
Then, the effect of increasing the coating adhesion strength was observed, and 20 at
%, The coating adhesion strength decreases relatively rapidly,
When it becomes 0 at%, it becomes 75 (N) more than the case of 20 at%.
Or more. In order to obtain sufficient film adhesion strength
Means that the amount of SiC added is within the range of 20 at% or less.
Is desired. Therefore, oxidation resistance and film adhesion strength
Considering both, the experimental results shown in FIGS.
It was found that the amount of SiC added to the heat-resistant hard coating 14 was 2.0
It is desired to be within the range of ２０20 at%. For this reason, heat-resistant hard
The composition of the components constituting the coating 14 is (Ti _xAl_1-xy
(SiC)_y) In N, 0.02 ≦ y ≦ 0.2
It is necessary to satisfy the conditional expression.

On the other hand, the (Ti _x Al _1-xy (SiC)
_y ) In the heat-resistant hard coating 14 made of N, according to the experiments by the present inventors, if the content x of Ti is less than 30 at%, sufficient toughness cannot be obtained in the heat-resistant hard coating 14, and 70 at%
If it exceeds, the heat-resistant hard coating 14 cannot have sufficient oxidation resistance. Therefore, the composition of components constituting the heat-resistant hard coating 14, in _{(Ti x Al 1-xy (} SiC) y) N, it is necessary to satisfy the condition that 0.3 ≦ x ≦ 0.7 . Therefore, considering the oxidation resistance and the coating adhesion strength of the heat-resistant hard coating 14 related to the SiC content y and the toughness and oxidation resistance of the heat-resistant hard coating 14 related to the Ti content x, (Ti _x Al _1-xy (S
iC) _y ) N, 0.3 ≦ x ≦ 0.7, 0.02
It is necessary to satisfy the conditional expression of ≦ y ≦ 0.2.

On the other hand, (Ti _x Al _1-xy (SiC)
_y ) In the heat-resistant hard coating 14 made of N, according to experiments by the present inventors, if the film thickness is less than 0.1 μm, sufficient wear resistance cannot be obtained, and if it exceeds 10 μm, the heat-resistant hard coating 14 Adhesive strength is reduced and the heat resistant hard coating 14
Cracks tend to occur, causing chipping. For this reason,
The thickness of the heat-resistant hard coating 14 fixed on the base material 12 by the arc discharge ion plating method is 0.1 to 10
The thickness is preferably in the range of μm, more preferably in the range of 1 to 8 μm.

Table 1 shows the heat-resistant hard-coated tool 10 of the invention.
The experimental values show the performance of
You. In this experimental example, Ti_0.5Al_0.5N
A tool provided with a coating consisting of
_0.4Al_0.4V_0.2A) a tool with a coating of N
Conventional example 3 (Ti_0.4Al_0.4Cr_0.2) N
A tool provided with a coating having a thickness of_0.48Al
_0.48Si_0.04Each tool with a coating of N
Prepared as (Example 1) of the present invention (Ti_0.49Al_0.49
 (SiC)_0.02 ) Tools with a coating of N
Example 2 (Ti _0.5Al_0.4(SiC)_0.1) From N
A tool provided with a coating consisting of (Ti_0.3A
l_0.6(SiC)_0.1) Tools with a coating of N
However, as Example 4, (Ti_0.45Al_0.45(SiC)
 _0.1A tool provided with a coating consisting of N
(Ti_0.4Al_0.4(SiC)_0.2) N film
Provided tools were prepared, and as Comparative Example 1, (Ti
_0.495Al_0.495(SiC)_0.01) With a coating of N
Tool as Comparative Example 2 (Ti_0.35Al_0.35(Si
C)_0.3) Tools with N coating are available
Have been.

The above 11 types of tools (samples) are WC-1
It is made of cemented carbide having a composition of 0Co and equivalent to JIS Z10, a diameter of 10.0 mm, a blade length of 25.0 mm, and a total length of 80.0 m.
m, a heat-resistant hard coating having a film thickness as shown in Table 1 was formed on the four-flute end mill by an arc discharge ion plating method. Table 1 shows the measured values of the coating hardness of these samples (end mills), the oxidation start temperature, and the maximum wear amount of the outer peripheral second face when the cutting test was performed under the following cutting conditions until 0.1 mm. The cut length measurements are shown.

(Cutting conditions) Work material: SKD 11 (hardness: 60 HRC) Cutting speed: 118 m / min Feed amount: 0.042 mm / t Cutting depth: AD (Axial depth) = 10.0 mm, RD (Radi
us depth) = 0.1mm Cutting oil: dry type (air blow) Cutting length: 39.2m

[0026]

[Table 1]

As is apparent from Table 1, in Examples 1 to 5 in which the amount of SiC added is 2 at% or more and 20 at% or less, the hardness and oxidation start temperature equivalent to or higher than those of the conventional examples 1 to 4 are obtained. , The maximum wear amount of the outer peripheral second surface is 0.
It can be seen that the cutting length until reaching 1 mm is longer than that of the conventional example and the comparative example, and the life is extended.

As described above, the heat-resistant hard film-coated tool 10 according to one embodiment of the present invention has been described with reference to the drawings. However, the present invention can be applied to other embodiments.

For example, the above-mentioned tool 1 coated with a heat-resistant hard coating
0 was made of cemented carbide,
Various tool materials such as a cermet and a CBN sintered body can be adopted.

Although the heat-resistant hard coating 14 of the heat-resistant hard coating-coated tool 10 is a single layer, it may be a laminate of a plurality of layers.

The heat-resistant hard coating 14 of the heat-resistant hard coating tool 10 is fixed to the surface of the substrate 12 by using an arc discharge ion plating method. A sputtering method may be used.

The above is merely an embodiment of the present invention, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part for explaining a configuration of a tool coated with a heat-resistant hard film according to an embodiment of the present invention.

FIG. 2 is a view showing the relationship between the amount of SiC added and the oxidation start temperature obtained by experiments in the heat-resistant hard coating of the heat-resistant hard coating tool shown in FIG.

FIG. 3 is a view showing the relationship between the amount of SiC added and the film adhesion strength obtained by experiments in the heat-resistant hard coating of the heat-resistant hard coating tool shown in FIG.

[Explanation of Signs] 10: Heat-resistant hard coating tool 12: Base material 14: Heat-resistant hard coating

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuhiro Park 2-9-33, Saimachi, Miyagino-ku, Sendai City, Miyagi Prefecture (72) Inventor, etc. 3-11-19 Koriyama, Taishiro-ku, Sendai City, Miyagi Prefecture (72) Inventor Masatoshi Sakurai 27F Term of 3-chome, Shiroun-cho, Toyokawa-shi, Aichi Prefecture (reference)

Claims (3)

[Claims] [Claim 1] _{(Ti x Al 1-xy (} SiC) y) N (
However, the respective composition ratios are 0.3 ≦ x ≦ 0.7, 0.02
≦ y ≦ 0.2) A tool coated with a heat-resistant hard coating, wherein a heat-resistant hard coating represented by the following composition is formed on the surface of a substrate. 2. The heat-resistant hard coating has a thickness of 0.1 to 10 μm.
The heat-resistant hard film-coated tool according to claim 1, wherein the tool is formed to have a thickness of: 3. The heat-resistant hard coating is fixed to the surface of the base material by an arc discharge ion plating method using a target formed from a titanium powder, an aluminum powder, and a SiC powder. Or 2) a tool coated with a heat-resistant hard coating.