JP2003291007A - Hard-coating coated tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard-coating coated tool hardly reacting with a material in dry and high speed cutting, extremely improved in crater wear resistance. <P>SOLUTION: In this hard coating coated tool coated with a hard coating on the base body surface, at least one layer of the hard coating contains boron and oxygen, the metallic component is an oxide nitride layer with Ti as the main component, expressed as TixMeyBz, where x, y and z satisfy x+y+z=100, 50x<100, 0.1<y<40 and 0.1<z<30; Me is at least one kind of elements of metals of groups 4a, 5a and 6a, such as Al, Si, Ca, K, Y, Mg, F excluding Ti, and the combining energy of Ti with oxygen and that of boron with nitrogen of the oxide nitride layer with Ti as the main component are confirmed by ESCA analysis. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard film coated tool used for cutting metal materials and the like, and particularly to a physical vapor deposition hard film coated tool having excellent crater wear resistance applied to high speed cutting and dry cutting. It is a thing.

[0002]

2. Description of the Related Art In recent years, in order to meet the demands for higher efficiency and higher accuracy of machining, dry machining has been emphasized in view of environmental problems and machining cost reduction in addition to high cutting speed. There is. Under such a cutting environment, a chemical reaction occurs between the wear-resistant film coated on the cutting tool surface and the material to be cut, and the tool life is not limited to the scrape wear of the flank, but also the crater of the rake face. The tendency to be strongly controlled by wear has become stronger. Conventional TiN, TiC
Under such a severe cutting environment, N and TiAlN coatings cannot actually obtain a sufficient cutting life due to an increase in crater wear caused by a chemical reaction with the work piece as the cutting temperature rises. is there. Especially in lathe machining, which is relatively continuous cutting, and high-speed high-feed milling,
It is extremely important to suppress this crater wear. As a countermeasure against this, special table H11-502775
Molybdenum disulfide disclosed in Japanese Patent Laid-Open No. 7-16
No. 4211, a lubricating coating made of tungsten carbide and diamond-like carbon and a hard coating having wear resistance are laminated, and a lubricating effect is utilized to suppress a rise in cutting temperature, and thus, between the coating and the workpiece. Cutting tools have been developed to suppress the diffusion phenomenon,
In both cases, the adhesion between the hard coating and the lubricating coating is poor, and the lubricating coating itself is extremely brittle, so these lubricating coatings easily peel or break during cutting, and are effective in the above cutting environment. It hasn't arrived yet. Further, a tool coated with a Cr-based lubricating coating has been proposed in Japanese Patent Laid-Open No. 11-156992, but the Cr-based coating has low hardness itself and extremely poor wear resistance, and is useful for improving crater wear resistance. Has not arrived.

[0003]

SUMMARY OF THE INVENTION In view of these circumstances, the present invention provides a hard coating which has little chemical reaction with the work material in response to dry cutting and speeding up, and has significantly improved crater wear resistance. An object is to provide a tool.

[0004]

Means for Solving the Problems In the hard coating tool in which a hard coating is coated on the surface of a substrate, the present inventors have found that at least one layer of the hard coating contains boron and oxygen and the metal component is (TixMeyBz). Is an oxynitride layer containing Ti as a main component, and x, y, and z are x + y + z = 10
0, 50x <100, 0.1 <y <40, 0.1 <z <
30, Me is an oxynitride containing 4a, 5a, 6a group metals other than Ti, one or more elements of Al, Si, Ca, K, Y, Mg and F, and having Ti as a main component. The material layer is a hard film-coated tool characterized in that binding energies of Ti and oxygen, and boron and nitrogen are confirmed in ESCA analysis, and increases the hardness of the oxynitride layer containing Ti as the main component. In addition, we succeeded in improving lubricity and, as a result, remarkably improving crater wear resistance. The present invention has been completed after confirming that there is little diffusion phenomenon in dry-type and high-speed cutting, excellent crater wear resistance, and extremely long life as a cutting tool.

[0005]

First, as a result of earnest research on the effects of various additive components using a TiN-based coating as an example, it was found that the addition of boron and the optimization of coating conditions can significantly improve the crater wear resistance of TiN. It was As a result of the investigation, the binding energy of boron and nitrogen was confirmed inside the TiN film, and the fact that the cutting temperature was reduced by 20 to 40% due to the lubricating effect of the phase having the binding energy of B and N was confirmed. Also, the friction coefficient of TiN with respect to steel is 0.8 to 0.4 due to the addition of boron.
It was also confirmed that the number has drastically decreased. Further, depending on the coating conditions, it was also confirmed that the hardness of the TiN coating was increased from 2200 to 2800 in Vickers hardness by adding boron. This is because the boron nitride is finely dispersed. That is, it was discovered that it is possible to strengthen the dispersion of a ceramic hard coating and at the same time to impart the lubricity of the dispersed phase to the hard coating.

However, even if boron is added, the cutting temperature may rise extremely depending on the cutting conditions, and in such a case, abrasion of the coating due to oxidation may occur. Therefore, it is necessary to further improve the oxidation resistance of the film. It was confirmed that the addition of oxygen densifies the crystal grain boundaries and reduces defects in the crystal grain boundaries, thereby improving the oxidation resistance. This is because the oxidation of the hard film progresses mainly due to the diffusion and permeation of oxygen into the crystal grain boundaries of the film, so that the densification of the crystal grain boundaries suppresses the diffusion of oxygen, resulting in improved oxidation resistance. It is supposed to do.

Next, in order to enhance the oxidation resistance, Ti and Al-based hard coatings, which are not very good in crater wear resistance but are extremely excellent in oxidation resistance, T added with boron and oxygen.
When the oxynitride film of i is multilayered, a synergistic effect is exhibited. Therefore, such multilayering is also effective in a cutting environment where the cutting temperature rises extremely. It can be said that it is more preferable.

In FIG. 1, a TiB target is used, a substrate bias is 300 V, nitrogen is 500 SCCM, oxygen is 20 SCCM as a reaction gas, and TiBO is used at a reaction pressure of 0.5 Pa.
ESCA (Electoron Spectroscopy for Che) of the N film coated by the arc ion plating method
mical Analysis) This is the analysis result. The boron contents are 4 atom% and 25 atom%. In FIGS. 1 and 2, a binding energy diffraction peak between Ti and oxygen is confirmed. In FIG. 3, the binding energy diffraction peaks of B and N are confirmed. FIG. 1 shows an example in which the bond between Ti and oxygen forms TiO.
FIG. 2 shows an example of forming TiO ₂ . When a phase is formed in the bond between B and N, TEM (Transmission
Electron Microscope) Observation results show that the nanocrystals have a size of several nanometers to several tens of nanometers, and various crystal forms exist. The large increase in hardness of the TiN layer is due to the fact that the nanocrystals generate lattice strain, and the crater wear resistance is significantly improved compared to TiN. It is considered that this is because the BN bond itself imparts excellent lubricity. When boron was added and the ion energy was small under the coating conditions, no nano-BN phase appeared. Therefore, it can be said that the optimization of coating conditions is also important in order to achieve high hardness by interposing nanocrystals.

In further high speed cutting and dry cutting, the coating is not only abraded by crater wear, but is also abraded by abrasion due to oxidation and deterioration of high temperature hardness of the coating, resulting in satisfactory results. Becomes difficult. Therefore, a part of Ti is W, Cr, Ta, Nb, Z
It has been found that by substituting r, Al, and Si, these elements can substitute for Ti atoms, solid-solution strengthening the entire coating, and improving high temperature hardness. When the amount of substitution of metal components other than Ti is 0.1 atom% or less, no clear effect is confirmed, and when it is 40 atom% or more, the toughness of TiN deteriorates. Further, with respect to boron, if the amount added is less than 0.1 atom%, the lubricity cannot be improved, and 3
If the content exceeds 0 atomic%, the toughness of TiN deteriorates.

Regarding the high temperature hardness which affects the rubbing wear, the hardness was measured after the coating film was held in vacuum at 800 ° C. for 1 hour. As a result, 10 atom% oxygen for nitrogen and 10 atom% for Ti were measured. % Boron (TiB) (O
N) has a Vickers hardness of 2200, while the amount of oxygen is the same, but 20 atomic% of another element is added to Ti. As an example, (TiCrB) (ON) is 260
0, (TiZrB) (ON) 2550, (TiNb
B) (ON) showed a high value of 2650. The system in which a part of Ti is replaced with a group 4a, 5a, or 6a metal of the periodic table, or Al or Si shows the same tendency. Regarding oxidation, TiN oxidizes when it exceeds 450 ° C, and powdered TiO
Will be transformed into. TiBN added with boron is 550 ° C
Oxidation starts at. Next, oxygen was added (TiB)
(ON) improves the oxidation start temperature to 700 ° C. Furthermore, the one obtained by substituting a part of Ti with 20 atomic% Al, Si and Y is (TiAlB) (ON) at 850 ° C.
B) (ON) at 1050 ° C, (TiYB) (ON) at 9
It was confirmed that no oxidation was confirmed up to 00 ° C. Therefore, the single layer of TiN layer containing boron and oxygen is 70
Although the effect is sufficiently exhibited up to 0 ° C, when the cutting temperature further rises, tool boundary wear accompanied by wear occurs due to oxidation generation. It is possible to improve the life of the.

[0011] Another important factor is lubricity. It was possible to improve the lubricity by adding boron, but it was further confirmed that the addition of Ca, Mg, K, F further improved the lubricity. This results in that Ca, Mg, and K are preferentially oxidized by cutting heat and a low-melting point oxide is formed on the surface of the coating to further improve lubricity. F results in improving the lubricity of the coating due to the lubricity of the halogen group itself. However, this coating tends to have high high-temperature hardness and high compressive residual stress, and peeling may occur due to high compressive residual stress. In such a case, it is preferable to form a laminate with a general hard coating. Particularly, it is preferable to use a TiAl-based hard coating having excellent oxidation resistance in combination with a multilayer structure or the like.
Oxidation is suppressed up to 850 ° C. in the TiAlN system, so when the cutting temperature further rises, a very long life is achieved.

By adding carbon to the above various hard coatings containing boron and oxygen, the lubricity of carbon is imparted and more preferable results are obtained. Further, the above-mentioned hard coating containing Ti and Ti containing boron and oxygen, and Ti and Al.
When laminated with a system film, both films have the same crystal morphology, and therefore the adhesion between layers is extremely strong. Regarding the multilayer structure, it is more preferable to coat the film surface side with a film having excellent lubricity, but it is not necessarily limited. Also, the number of layers itself is not particularly limited.

As described above, the hard coating tool according to the present invention, which has greatly improved crater wear resistance and improved oxidation resistance, rubbing wear resistance and lubricity, is
It is also effective for tools used for high-feed milling cutting, but it is also commonly used for chemical vapor deposition (hereinafter referred to as CVD), which has a conventional alumina coating and a hard coating with a thickness of about 10 μm. It has become possible to apply it to the turning field where the coated tool according to (. Since turning is a relatively continuous cutting, tool life is often dominated by crater wear. Also in the present invention, when the film thickness is thin, the crater wear resistance of the CVD film is inferior, but by coating the rake face where crater wear occurs, 3 μm or more, the crater wear resistance comparable to the CVD film is obtained. I confirmed that it is possible to have. It can be said that the thickness of the coating is more preferably 3 μm to 15 μm.

Further, in order to improve the tool performance, Ti
It has been found that it is effective to add the third component to the AlN-based film. This is because the third component solid-solution strengthens the TiAlN film. The hard film-coated tool of the present invention is not particularly limited in its coating method, but when considering the thermal influence on the coating base material, the fatigue strength of the tool, the adhesion of the coating, etc., the arc discharge method is used. Ion plating physical vapor deposition is preferred.
In the present invention, the coating conditions as to whether or not nanocrystals are present have the same tendency as the TiBON system. Hereinafter, the present invention will be described based on examples.

[0015]

Example 1 Using an arc ion plating device,
Targets made of various alloys, which are evaporation sources of metal components, and reaction gases, such as nitrogen gas, oxygen gas, and methane gas, are selected to obtain a target film. In the TiAlN-based film, the coating substrate temperature is 400 ° C., the reaction gas is Pressure 1.0
Under the conditions of Pa and a bias voltage of 150 V applied to the substrate, a tool was prepared by coating the coatings shown in Table 1 on a carbide insert for milling, which is a coated substrate. T in the example of the present invention
The i-type hard layer was coated under the same temperature with a bias potential of 300 V and a reaction gas pressure of 0.5 Pa with a phase having a BN bond interposed. Boron was contained in the film by adding a required amount of Ti to the target. The cemented carbide used for the insert is JIS-P40 grade cemented carbide. Inventive Example 36 is a case in which a bias potential of 100 V and a reaction gas pressure of 0.5 Pa were used to reduce the ion energy and nanocrystals were not confirmed.

[0016]

[Table 1]

In the comparative example, coatings other than TiAl were also coated under the same conditions. A cutting test was performed using the obtained hard coating-coated insert. Crater wear dominates the tool life under this cutting condition, so the tool life was taken as the cutting length when the tool became uncutable due to crater wear. The cutting specifications are shown below. In milling where the feed per blade exceeds 1 mm, the cutting temperature locally rises and crater wear tends to occur. The insert cutting conditions are 100 mm in width x 25 in length by milling using a round top insert with a tool shape RDMW1604 MOTN.
0mm chamfering, work material SKD61 (HRC4
5), depth of cut 1.0 mm, cutting speed 200 m / mi
n, feed 2.0 mm / blade, dry cutting. Table 1 also shows the cutting time leading to chipping. In addition, the film thickness shown in the table shows the film thickness of the rake face.

From Table 1, it can be seen that Examples 1-36 of the present invention have a markedly improved life as a whole. In all the comparative examples of the present invention, which had a short life due to crater wear, it is largely due to the improvement in crater wear resistance. Inventive Examples 1 to 15 to which oxygen and boron were added are all cases in which the Me component is in the 4a, 5a, and 6a groups, and are confirmed to have a longer life than Comparative Examples 41 to 44 that do not contain the Me component. Was done. Inventive examples 16 to 18 are examples in which Al, Si and Y are added, and inventive examples 19 to 22 are examples in which K and Ca are added,
Furthermore, the wear resistance was improved. Inventive Examples 25 to 29 are TiA
This is an example in which a 1N-based coating is laminated, and it is clear that the life is further improved as compared with Inventive Example 2. Inventive Examples 30 to 32 are examples of laminating with a general hard coating.
Both have a significantly longer life than Comparative Examples 38 and 40.
In Comparative Examples 38 and 40, peeling of the film occurred. Invention Example 3
No. 6 is a case where nanocrystals are not present depending on the coating conditions, but it is a result which is slightly inferior to that of Inventive Example 2 but is sufficiently satisfactory. Comparative Examples 45 to 50 are cases where the composition range is outside the scope of the present invention, but the lubricating effect was not sufficient, or the coating film was broken or peeled during cutting, and it was not possible to obtain a satisfactory result.

[0019]

Example 2 Based on the method of Example 1, the cermet inserts for turning (chip shape: TNGG110302R) were coated with the coatings of the examples of the present invention and comparative examples shown in Table 1, and turning was performed. _{60TiCN-10WC-10TaC-5Mo 2} C-5 The composition of the cermet used in weight%
It is Ni-10Co. The cutting conditions are S53 as the work material.
Using C, the cutting speed was 220 m / min, the incision was 1 mm, the feed was 0.15 mm / rev, and the water-soluble cutting oil was used. In both cases, heat generation increases as crater wear progresses, and flank wear tends to increase. The life was determined when the flank wear value was 0.1 mm. The cutting time to the end of life is shown in Table 2.

[0020]

[Table 2]

From Table 2, it is recognized that the examples of the present invention have a significantly improved life as a whole even in turning. All comparative examples
The shorter life due to crater wear is largely due to the improvement in crater wear resistance. Inventive Examples 1 to 15 to which oxygen and boron were added are all cases in which the Me component is in the 4a, 5a, and 6a groups, and are confirmed to have a longer life than Comparative Examples 41 to 44 that do not contain the Me component. Was done. Inventive Examples 25 to 29 are examples in which a TiAlN-based coating is laminated, and it is clear that the life is further improved as compared with Inventive Example 2. Inventive Examples 30 to 32 are examples of laminating with a general hard coating. Comparative Example 38,
It has a much longer life than 40. In Comparative Examples 38 and 40, peeling of the coating occurred even during turning. Invention Example 3
No. 6 is a case where nanocrystals are not present depending on the coating conditions, but it is a result which is slightly inferior to that of Inventive Example 2 but is sufficiently satisfactory. Comparative Examples 45 to 50 are cases where the composition range is outside the scope of the present invention, but the lubricating effect was not sufficient, or the coating film was broken or peeled during cutting, and it was not possible to obtain a satisfactory result.

[0022]

Example 3 An example of the present invention was prepared under the same conditions as in Example 1 using a target obtained by substituting a part of Al of the TiAl metal target with another component. The same cutting evaluation as in Example 1 was performed, and the results are shown in Table 3.

[0023]

[Table 3]

From Table 3, it is possible to further improve the life by adding the third component to the TiAl hard coating. This is because the addition of the third component further strengthens the TiAlN-based coating by solid solution and improves the oxidation resistance.

[0025]

As described above, the hard coating tool of the present invention is superior in crater wear resistance as compared with the conventional coated tool,
It provides a much longer tool life in dry high-speed cutting, and is extremely effective in improving productivity, reducing costs, and improving the environment in cutting.

[Brief description of drawings]

FIG. 1 is a result of ESCA analysis of a film of the present invention, showing a binding energy diffraction peak between Ti and oxygen,
An example of forming TiO will be shown.

FIG. 2 is a result of ESCA analysis of a film of the present invention, showing a binding energy diffraction peak of Ti and oxygen,
An example of forming TiO ₂ is shown.

FIG. 3 is a result of ESCA analysis of the film of the present invention, showing the binding energy diffraction peaks of B and N.

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Claims (5)

[Claims] 1. A hard coating tool having a hard coating on the surface of a substrate, wherein at least one layer of the hard coating contains boron and oxygen, and the metal component is an acid mainly composed of Ti represented by (TixMeyBz). Nitride layer, x, y, z
Is x + y + z = 100, 50x <100, 0.1 <y
<40, 0.1 <z <30, and Me is a 4a, 5a, or 6a group metal other than Ti, Al, Si, Ca, K, Y,
An oxynitride layer containing at least one element of Mg and F and having Ti as a main component is characterized by the binding energy of Ti and oxygen, boron and nitrogen being confirmed by ESCA analysis. Film coated tool. 2. The physical vapor deposition hard film coated tool according to claim 1, wherein the oxynitride layer containing Ti as a main component contains carbon. 3. A hard coating tool according to claim 1 or 2, wherein the coating is composed of an oxynitride layer of Ti, Ti and Al as main components and at least one of C, N and O. A hard coating tool, characterized in that two or more layers are coated. 4. The hard coating tool according to claim 3, wherein a part of Al in the hard compound layer is replaced with 4a or 5 in the periodic table.
A hard-coated tool characterized in that it is substituted with one or more components of a, 6a group metals and Si. 5. The hard coating tool according to any one of claims 1 to 4, wherein the substrate is a cemented carbide or cermet alloy, and the total thickness of the coating is 3 μm to 15 μm on the rake face. Coated tool.