JP2005177952A - Compound hard film coated tool and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool covered with a hard film capable of cutting at high speed/in high performance and excellent in abrasion resistance. <P>SOLUTION: This hard film coated tool is constituted by covering at least one layer each of a hard film A which is a hard film made of (Ti<SB>a</SB>, Al<SB>b</SB>, M<SB>c</SB>)(C<SB>1-d</SB>N<SB>d</SB>) in which M is one or more than two kinds of metal and semimetal elements, (a), (b) and (c) respectively show atomic ratios of Ti, Al and M, (d) shows an atomic ratio of N and of a composition of 0.02≤a ≤0.2, 0.8≤b ≤0.95, a+b+c=1 0.5≤d≤1, and a hard film B made of vanadium carbonitride. The hard film B is applied on the base material side rather than the hard film A. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a composite hard film coated tool for improving the wear resistance of a cutting tool such as a tip, a drill, a tap, an end mill, a hob, and a broach, and a method for manufacturing the same.

Conventionally, hard coatings such as TiN, TiCN, and TiAlN have been applied for the purpose of improving the wear resistance of cutting tools based on cemented carbide, cermet, or high-speed tool steel. In particular, since a composite nitride film of Ti and Al (hereinafter referred to as TiAlN) exhibits excellent wear resistance, high-speed cutting and baking can be used in place of the titanium nitride, carbide and carbonitride films. It has been applied to cutting tools for cutting hard materials such as steel inserts. The TiAlN film is known to increase the hardness of the film and improve the wear resistance by adding Al. However, Patent Document 1 discloses that TiAlN is (Al _x , Ti _1-x ) N. It is shown that ZnS-type soft AlN is precipitated when the Al composition ratio x is 0.7 or more. Patent Document 1 states that “If the amount of Al (x) exceeds 0.75, the hard film approximates to AlN, resulting in softening of the film, resulting in insufficient hardness and easy flank wear. To cause. " Further, FIG. 3 of Patent Document 1 shows the relationship between the Al composition ratio and the film hardness, and the hardness decreases from the vicinity where the Al composition exceeds 0.6. This is because the Al composition ratio x is 0.6 to 0.7. During this time, ZnS-type AlN began to precipitate, and as the Al composition ratio increased, the precipitation of ZnS-type AlN increased, suggesting that the film hardness decreased. Furthermore, the same patent shows that with regard to oxidation resistance, when the Al composition ratio x is 0.56 or more and the oxidation start temperature is 800 ° C. or more, the oxidation start temperature tends to increase as the x value increases. The upper limit of the Al composition ratio specified in consideration of hardness is about 850 ° C. at 0.75. Patent Document 2 describes that by adding Cr to TiAlN, the proportion of the rock salt structure type AlN can be increased to increase the hardness and improve the oxidation resistance. The upper limit of the ratio is only 0.8.

That is, in the conventional method, there is a limit to increase the hardness by increasing the Al composition ratio, so the hardness and oxidation resistance cannot be increased at the same time. As a result, there is a limit to improving the wear resistance. It was. However, in recent years, there has been a demand for higher speed and higher efficiency as the usage conditions of cutting tools, and in order to realize such cutting tools, composite hard coatings for cutting tools that exhibit even better wear resistance have been developed. It has been demanded. Therefore, the inventors conducted research on the TiAlMn film using the melt evaporation type ion plating method (hereinafter referred to as the dissolution method). As a result, even if Al exceeds 80%, the hardness does not decrease, and the oxidation resistance A good film (Applicant's unpublished Patent Document 3). However, with this method, it is difficult to obtain a film thickness of 2 μm or more, and depending on the cutting conditions, an undercoating film such as TiCN is required to exhibit sufficient performance as a cutting tool.
Japanese Patent No.26444710 JP 2003-71610 A Patent application No. 2003-325406 (unpublished)

  The subject of this invention is providing the cutting tool which coat | covered the hard film | membrane excellent in the abrasion resistance which can perform high-speed and highly efficient cutting, and its manufacturing method.

Therefore, the present invention provides a hard tool made of (Ti _a , Al _b , M _c ) (C _1-d N _d ) on a base material of a cutting tool based on cemented carbide, cermet or high-speed tool steel. A film, wherein M is one or more metal and metalloid elements, a, b and c are atomic ratios of Ti, Al and M, respectively, d is an atomic ratio of N,
0.02 ≦ a ≦ 0.2, 0.8 ≦ b ≦ 0.95, a + b + c = 1 0.5 ≦ d ≦ 1
A hard film coating tool formed by coating at least one layer each of a hard film A having the following composition and a hard film B made of vanadium carbonitride, wherein the hard film B is closer to the substrate than the hard film A is. The above-mentioned problems have been solved by a hard film-coated tool characterized by being coated.

The above-described present invention provides a hard film-coated tool that is easy to obtain a film thickness of 2 μm or more, is capable of high-speed and high-efficiency cutting, and is coated with a hard film excellent in wear resistance.
As a result of diligent research aimed at realizing a hard coating for a cutting tool that exhibits better wear resistance, the inventors have increased the Al ratio to more than 0.8 by increasing the plasma energy per atom. It was found that the hardness does not decrease even in the coating. And as a result of conducting research focusing on the dissolution method as a means, the film having an Al ratio of 0.8 to 0.95 is improved in hardness and oxidation resistance, and as a result, it has been found that the wear resistance is dramatically improved. As a result of further research on control of target component ratio and relative density, and plasma energy, the hard coating A was conceived. Furthermore, the inventors focused on the vanadium carbonitride film as the optimum base film for the TiAlMN film, and as a result of research, we found that the initial metal vanadium film thickness, nitrogen and hydrocarbon gas partial pressure, base bias, etc. Thus, the hard coating B, which is a vanadium carbonitride coating superior to the titanium-based coating in terms of adhesion, wear resistance, and lubricity, was successfully obtained.

Preferably, the vanadium carbonitride is VC _1-e N _e , and e is preferably 0.5 ≦ e ≦ 1 in terms of the atomic ratio of N 2. Further, the element M is preferably Si, Cr or Ni.

More preferably, the film thickness of the hard coating A is 0.5 μm or more and 2 μm or less, or the film thickness of the hard coating B is 0.5 μm or more and 5 μm or less. If the film thickness of the hard film A is less than 0.5 μm and the film thickness of the hard film B is less than 0.5 μm, the effect of wear resistance in cutting cannot be expected, and if the film thickness of the hard film A exceeds 2 μm, If the film thickness exceeds 5 μm, minute chipping is likely to occur in the ceramic hard film layer, so it was limited to this range.
More preferably, a hard film coating in which a hard film with more excellent wear resistance is formed by forming a lubricating functional film of NiO _x , DLC, MoS ₂ or BN on the opposite side of the base of the hard film. A tool can be provided.

The best mode hard coat coated tool for carrying out the present invention is (Ti _a , Al _b , M _c ) on the base material of a cutting tool based on cemented carbide, cermet or high speed tool steel. (C _1-d N _d ) Hard film, where M is one or more metals and metalloid elements, and a, b, and c represent the atomic ratios of Ti, Al, and M, respectively. , D represents the atomic ratio of N,
0.02 ≦ a ≦ 0.2, 0.8 ≦ b ≦ 0.95, a + b + c = 1 0.5 ≦ d ≦ 1
A hard film coating tool formed by coating at least one layer each of a hard film A having the following composition and a hard film B made of vanadium carbonitride, wherein the hard film B is closer to the substrate than the hard film A is. A hard-coated tool characterized by being coated. In addition, when vanadium carbonitride is expressed by VC _1-e N _e (e is an atomic ratio of N), it is desirable that 0.5 ≦ e ≦ 1.

  The present invention also prescribes a method for forming the hard film for a cutting tool described above, and vaporizes and ionizes a metal in a film-forming gas atmosphere, and promotes plasma formation of the film-forming gas together with the metal. The gist is to film. Further, a melt evaporation type ion plating method (hereinafter abbreviated as a melting method) in which a metal constituting a target is evaporated and ionized by using an electron beam by hollow cathode discharge to form a film defined by the present invention on a workpiece. ) Is preferably formed. In this case, the bias potential applied to the object to be processed is preferably -50V to -300V with respect to the ground potential. In addition, the temperature of the object to be processed during film formation (hereinafter sometimes referred to as substrate temperature) is preferably within the range of 300 ° C to 800 ° C, and the partial pressure or total pressure of the reaction gas during film formation is It is desirable to set it to 0.05 Pa or more and 1 Pa or less. In addition, the said reaction gas in this invention means nitrogen gas, methane gas, ethylene, acetylene, ammonia, hydrogen, or the gas containing the element required for the component composition of the film | membrane which mixed these 2 or more types other than these. A rare gas such as Ar used is called an assist gas, and these are collectively referred to as a film forming gas.

A melt evaporation type ion plate having a crucible exchange function, that is, a function capable of automatically switching to one of other crucibles while maintaining a vacuum state after using one of at least two crucibles in a vacuum atmosphere. A compacting body in which 100g of metal vanadium was placed in one of the graphite crucibles and 30g of mixed powder of Ti65Al35at% was molded at 2GPa using a φ40 cylindrical mold was placed in another crucible. . After heating and cleaning, the metal vanadium is melted and evaporated using an HCD gun in an argon / nitrogen mixed atmosphere of about 0.1 Pa, and carbonized stepwise to C: N = 3: 7 while evaporating about 30 g. Hydrogen gas was introduced to form a VCN film on the carbide end mill substrate. Subsequently, the crucible was switched and melted and evaporated using an HCD gun converged so that the plasma beam diameter on the upper surface of the green compact became about 10 mm in an argon-nitrogen mixed atmosphere of about 0.1 Pa to form a TiAlN film. . At this time, the plasma power was increased from 3000W to 8000W by 500W per minute.
Similarly, VCN + TiAlSiN, VCN + TiAlNiN, and VCN + TiAlCrN films were formed on a carbide end mill using compacted bodies of Ti60Al35Si5at%, Ti60Al35Ni5at%, and Ti60Al35Cr5at%.
Similarly, 95g of metal vanadium and 5g of metal titanium are placed in one of the graphite crucibles, and a compacted compact of Ti65Al35at% is placed in another crucible, and a VTiCN + TiAlN coating is formed on the carbide end mill substrate. Filmed. The metal component of the VTiCN layer at this time was V: Ti = 93: 7 at%.
Table 1 shows the results of the cutting test using the obtained end mill.
The carbide end mill measured the flank wear width when the cutting length was 50m. The cutting specifications are shown below. Carbide end mills showed wear resistance equal to or better than TiAlN films formed by the arc method.
(Carbide end mill cutting conditions)
Tool: φ10 carbide 6 flute square end mill Cutting method: Side cut Downcut Workpiece material: SKD61 (hardness 53HRC)
Cutting depth: 10mm in the axial direction, 0.2mm in the radial direction
Cutting speed: 785m / min, Feed: 0.07mm / Blade cutting length: 50m, Lubricant: None (Air blow)

  A cemented carbide insert coated with AlN (arc method), TiAlSiN (arc method) and VCN + TiAlCrN (compact melting method) was heated to 1000 ° C. in the atmosphere, held for 1 hour, and then cooled. The oxidation depth was measured by the Calotest method on the sample surface. The results are shown in Table 2.

In the same manner as in Example 1, using a melt evaporation type ion plating apparatus with a crucible exchange function, the ACN method is used to form a VCN film on a carbide end mill substrate, and then the crucible is switched to a TiAlN film. Was formed on a carbide end mill substrate, and a lubricating functional film of NiO _x was formed on the uppermost layer. A cutting test using a carbide end mill similar to Example 1 was conducted. The end mill flank wear was about 2.5% less than the inventive product.
[Effect of Best Embodiment of the Present Invention]

  From the above-mentioned best embodiment of the present invention, the hard film coated tool of the present invention is a hard film excellent in wear resistance, capable of obtaining a film thickness of 2 μm or more, capable of high speed and high efficiency cutting. A coated hard-coated tool was provided.

Preferably, the vanadium carbonitride is VC _1-e N _e , and e is preferably 0.5 ≦ e ≦ 1 in terms of the atomic ratio of N 2. Further, the element M is preferably Si, Cr or Ni.

  More preferably, the film thickness of the hard coating A is 0.5 μm or more and 2 μm or less, or the film thickness of the hard coating B is 0.5 μm or more and 5 μm or less. When the film thickness of the hard film A is 0.5 μm or less and the film thickness of the hard film B is 0.5 μm or less, the effect of wear resistance in cutting cannot be expected, and the film thickness of the hard film A is 2 μm or more. However, if the thickness is 5 μm or more, minute chipping is likely to occur in the ceramic hard film layer.

Claims (9)

A hard coating made of (Ti _a , Al _b , M _c ) (C _1-d N _d ) on a base material of a cutting tool based on cemented carbide, cermet or high-speed tool steel, Is one or more metal and metalloid elements, a, b and c are the atomic ratios of Ti, Al and M, respectively, d is the atomic ratio of N,
0.02 ≦ a ≦ 0.2, 0.8 ≦ b ≦ 0.95, a + b + c = 1 0.5 ≦ d ≦ 1
A hard film coating tool formed by coating at least one layer each of a hard film A having the following composition and a hard film B made of vanadium carbonitride, wherein the hard film B is closer to the substrate than the hard film A is. A hard coating tool characterized by being coated. 2. The hard film-coated tool according to claim 1, wherein the vanadium carbonitride is VC _1-e N _e and e is expressed as an atomic ratio of N, and 0.5 ≦ e ≦ 1. The hard-coated tool according to claim 1 or 2, wherein the value of d is 1. The hard film-coated tool according to any one of claims 1 to 3, wherein the element M is Si, Cr, or Ni. The hard film-coated tool according to any one of claims 1 to 4, wherein the film thickness of the hard film A is 0.5 µm or more and 2 µm or less. The hard film-coated tool according to any one of claims 1 to 5, wherein the film thickness of the hard film B is 0.5 µm or more and 5 µm or less. The hard coating B is a hard coating containing a nitride constituent element other than vanadium, and a metal component other than vanadium is 10% or less in atomic ratio with respect to vanadium. The hard film coating tool according to any one of the above. The hard film-coated tool according to any one of claims 1 to 7, wherein a lubricating functional film of NiO _x , DLC, MoS ₂ or BN is formed on the uppermost layer of the hard film. Maintain a vacuum after using one of at least two crucibles in a vacuum atmosphere on the base of a cutting tool based on cemented carbide, cermet or high speed tool steel in a vacuum atmosphere And using a melt evaporation type ion plating apparatus having a function capable of automatically switching to one of the other crucibles, and using a metal vanadium as an evaporation material in the first crucible and claiming by a melt evaporation type ion plating method. 1 in which the hard coating B is formed, and the sintered body or the compacted body containing aluminum in the second crucible is automatically switched to the evaporation source while maintaining the vacuum state. A method for producing a composite hard coating-coated tool, comprising continuously performing the step 2 of forming the hard coating B of claim 1 by an ion plating method.