KR20050002178A - A multi-layer with high antiwear and lubricous coated to cemeted carbide tool - Google Patents

Abstract

PURPOSE: To provide a multi-layered hard thin film of coated hard alloy exhibiting superior performance when high speed processing Al and Al alloy having the total thin film thickness of 1.0 to 2.5 μm by depositing a CrN thin film having thickness of 0.5 to 1.5 μm as the outermost layer, thereby improving lubrication characteristics. CONSTITUTION: In a multi-layered hard thin film used for coating the surface of a cutting tool or wear resistance tool for processing Al and Al alloy, or Cu and Cu alloy, the multi-layered hard thin film comprises a multi-layered thin film of TiAlCrN/TiAlN deposited on the surface of the tool in thickness of 0.5 to 1.5 μm; a Cr metal layer deposited on the multi-layered thin film of TiAlCrN/TiAlN in thickness of 0.2 to 0.5 μm; and a CrN thin film as the outermost layer deposited on the Cr metal layer in thickness of 0.5 to 1.5 μm so that the total thin film thickness becomes 1.0 to 2.5 μm.

Description

A multi-layer with high antiwear and lubricous coated to cemeted carbide tool}

The present invention relates to a multilayer hard thin film, and more particularly, to a multilayer hard thin film having excellent abrasion resistance and lubricity for a cutting tool / abrasion resistant tool having a performance suitable for cutting a heavily welded workpiece.

When cutting aluminum, which is a soft material with high adhesion, general carbide or diamond tools without coating, and recently DLC (Diamond like carbon) coating tools are applied, and some TiN thin films using PVD are applied to the tools. have.

Among these diamond tools, PCD tools, CBN tools, and diamond coated tools are suitable for high speed cutting of aluminum due to their excellent wear resistance, but they are susceptible to damage due to the characteristics of diamond, which is easy to cause breakage in intermittent operations and is expensive. In addition, DLC coating tools are recently attracting attention as a thin film showing excellent properties for aluminum processing due to their excellent lubricity. In general, DLC has a performance and price that is halfway between diamond tools and general coating tools, and its application is expanding in the aluminum processing field.

The weldability of aluminum is determined by the content of Si, which is a containing element. The higher the content of Si, the more weldable. DLC and diamond tools are used. And TiN thin film using some PVD method is applied. The application of TiCN and TiAlN-based thin films, which are superior in hardness to TiN in most cutting applications, is common, but it is not actively applied to aluminum processing because these films do not have good surface roughness compared to TiN, which is not normal wear. Welding is the end of the tool life.

For this reason, in the medium and low speed machining of aluminum, many carbide tools without coating are still applied, but recently, a thin film having improved surface roughness of TiAlN thin film or laminated TiN thin film on TiAlN thin film has been developed. Is being applied. However, due to the limitation of thin film hardness, high-speed cutting shows a significantly inferior wear resistance compared to DLC and diamond tools.

Recently, in order to improve the performance of cutting tools or wear-resistant tools, TiAlMN-type thin films in which a metal element, such as silicon (Si) and chromium (Cr), are added to an existing TiAlN-coated hard alloy has been developed.

In the case of TiAlMN coated hard alloy, the hardness is higher than Hv 3000 and the oxidation temperature is higher than 1000 ° C., which shows superior wear resistance at high cutting speed than TiAlN coated hard alloy when coated on the surface of a cutting tool or wear resistant tool. The thin film layer was intersected with a TiAlN / TiAlCrN structure and laminated to 100-1700 layers to improve wear resistance and impact resistance to prevent breakage during intermittent cutting.

The TiAlCrN coated hard layer is composed of (TiaAlbCrc) N, where a + b + c = 1 and c = 5 atomic% -12 atomic%, and the TiAlN coated hard layer is composed of (TiaAlb) N. Where a + b = 1, a = 50 atomic% -60 atomic%, and b = 50 atomic% -40 atomic%, the TiaAlbCrcN-coated hard layer is characterized in that the growth direction is first (200) plane. to be.

Such is disclosed in Korean Patent Publication No. 8359, to which the applicant has applied for a patent.

The present invention is to provide a thin film capable of high-speed processing, such as DLC, diamond tools by improving the cutting performance, while the price is similar to the existing TiN deposition tool in depositing materials with high deposition such as aluminum using PVD method As mentioned in Korean Patent Laid-Open No. 8359, a thickness of 0.5 μm-1.5 μm is obtained by crossing TiAlCrN-coated hard alloy and TiAlN-coated hard alloy containing Ti as a metal element to TiAlN-coated hard alloy with 100-1700 layers. Laminated coating improves high temperature hardness and oxidation start temperature, and deposits Cr metal layer 0.2㎛-0.5㎛ on it to improve adhesion between TiAlCrN multilayer thin film and CrN thin film and to reduce impact applied to the outside of thin film during cutting. I want to play a role as. Therefore, in the present invention, the outermost layer is coated with a CrN thin film having a thickness of 0.5 μm-1.5 μm to improve welding resistance, and thus, a coated hard alloy exhibiting excellent performance in high-speed processing of aluminum and aluminum alloys having a total film thickness of 1.0 μm-2.5 μm. Its purpose is to provide a multilayer hard thin film.

In addition, the CrN thin film applied in the present invention has a lower hardness than the TiN thin film but is excellent in corrosion resistance and lubricity, and thus may be applied to a place where friction of molds, automotive parts, etc. occurs than general wear tools.

1 is a surface roughness graph of each thin film for the real name and the prior art

In order to achieve the above object, the present invention,

Multi-layered thin film for coating aluminum and aluminum alloys or cutting tools for machining copper and copper alloys or wear-resistant tools, wherein a multilayer thin film of TiAlCrN / TiAlN is deposited in a thickness of 0.5 µm to 1.5 µm, and a Cr metal layer is deposited thereon. Deposition at 0.5 μm and CrN thin film at 0.5 μm to 1.5 μm as the outermost layer to provide a multilayer rigid thin film having a total thickness of 1.0 μm to 2.5 μm.

Here, the multilayer hard thin film is preferably deposited on the tool by the UBM method and / or arc method,

The multi-layered thin film of TiAlN / TiAlCrN is preferably coated with 100-1700 layers.

In addition, the TiAlCrN thin film is composed of a composition of (TiaAlbCrc) N, where a + b + c = 1, c = 5 atomic%-12 atomic%,

Preferably, the TiaAlbCrcN coating layer has a growth direction of (200) plane.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

As a coating method used in the present invention, a multilayer coating of a TiAlCrN thin film and a TiAlN thin film was performed by the UBM method by using a hybrid method of an unbalanced magnetron sputter method (UBM method) and an arc method. Cr and CrN thin film coating was carried out.

In the manufacturing process, a rotary pump, a booster pump, and a turbo pump are evacuated to 5.0 × 10 ⁻⁵ Torr or less, and the furnace temperature is heated to 450 ° C. using a heater. After the temperature increase, N2 is introduced into the Ar gas and the reaction gas, and a bias voltage is applied to 50V. After the deposition of the TiAlCrN thin film and the TiAlN thin film by using the UBM method at 0.5㎛-1.5㎛, the deposition of Cr metal layer 0.2㎛-0.5㎛ by using the arc method without adding gas, and N2 was added as a reaction gas to CrN Thin films were deposited at 0.5 μm-1.5 μm.

Example 1

First, the coated material was cemented carbide, coated with K10 ISO standard SPCN1203EDR for milling cutting test, and coated with K10 ISO standard VCGT160412 for turning cutting test.

In order to find the optimum thin film for aluminum processing by understanding the characteristics according to the type of thin film, the surface roughness measurement and the hardness of the thin film were measured for the existing thin film and the thin film for the present invention. The coating method of the present invention was coated using the hybrid method as described above, and all the thin films tested to eliminate the variation in the film thickness were coated until the film thickness was 2 μm.

Table 1 below shows the hardness and surface roughness of the thin film prepared by the present invention and the conventional coated hard alloy.

As shown in Table 1, when comparing TiN, CrN, TiAlN and TiAlCrN multilayer thin films manufactured in the prior art, the CrN thin film had the lowest hardness, but the surface roughness was the best, and the TiN thin film had the hardness higher than CrN. However, the surface roughness was somewhat rough. For this reason, TiN thin films are widely used in wear resistant tools rather than CrN thin films.

The surface roughness of TiAlN thin film and TiAlCrN multilayer thin film was similar, but it was very rough compared to TiN, Crr thin film and the hardness was very good.

When TiN and Cr films were deposited on the TiAlCrN multilayer thin films having the highest hardness, the surface roughness decreased slightly compared to that of the TiN and Cr single layer thin films, but the TiAlCrN multilayer thin films showed excellent surface roughness.

1 is a graph showing the surface roughness of each thin film.

division Thin film structure Thin Film Hardness (HV) Surface Roughness (Ra) One TiAlCrN / Cr / CrN 3070 0.07 μm 2 TiAlCrN / Ti / TiN 3120 0.14 μm 3 TiAlCrN / TiAlN Multilayer 3100 0.24 μm 4 CrN 2100 0.05 μm 5 TiN 2500 0.1 μm 6 TiAlN 2900 0.2 μm

Table 1

Example 2

Cutting test was carried out using the sample coated in Example 1. The cutting test was performed by turning and milling tests on the same thin film, and the test conditions are shown in Table 2 and the results are shown in Table 3.

For comparison of cutting performance, samples with DLC coated on K10 and K10 carbide were tested together.

The milling test machined the square material of 150 mm in width and 265 mm in length.

As a result of turning test, DLC coating showed the best results, CrN and TiN thin films showed similar wear and TiAlCrN + CrN structure of the present invention showed the best after DLC.

In the milling test, the TiAlCrN + CrN thin film of the present invention showed better results than DLC. In the turning and milling test, the CrN and TiN thin films showed better results than TiAlN, which is superior in hardness and oxidation resistance. The result was poor chip life due to welding, and as a result, the surface roughness of the thin film had a greater effect on the tool life than the hardness and other properties of the thin film when the material was heavily welded.

Turning test Milling test Workpiece AC8A Left Cutting speed (m / min) 700 800 Feed amount 0.3 (mm / rev) 0.3 (mm / mm) Depth of cut (mm) 2.0 Left Coolant U Left Processing time 10 min cutting 12pass cutting

TABLE 2

division Thin film structure Clearance wear (mm) Turning test result Milling test results One TiAlCrN / Cr / CrN 0.19 0.05 2 TiAlCrN / Ti / TiN 0.26 0.13 3 TiAlCrN / TiAlN Multilayer 0.42 0.26 4 CrN 0.42 0.21 5 TiN 0.41 0.24 6 TiAlN 10 minutes chipping 0.39 7 Carbide (K10) 0.49 8pass chipping 8 DLC 0.10 0.08

TABLE 3

Example 3

Cutting tests were performed to analyze the effects of the thickness of the TiAlCrN multilayer, Cr metal layer, and CrN layer of the present invention. The total thin film was deposited so as not to exceed 4.0 μm. In the case of the processing of highly weldable material, if the thin film thickness of the tool is thick, peeling is likely to occur due to welding.

Test conditions were the same as in Example 2 and the results are shown in Table 4.

As a result of the test, when the Cr metal layer exceeded 0.5 μm, the cutting performance was decreased. When the Cr metal layer was not deposited, the separation between the TiAlCrN multilayer thin film and the CrN thin film occurred. When the thickness of TiAlCrN multilayer and CrN thin films were deposited below 1.5 μm, respectively, the total thin film thickness exceeded 2.5 μm, resulting in poor cutting performance due to welding.

division Thin film thickness (㎛) Total film thickness Clearance wear (mm) TiAlCrN / TiAlN Multilayer Cr layer CrN layer Turning milling Invention One 0.5 0.5 0.5 1.5 0.18 0.06 2 1.0 0.5 0.5 2.0 0.19 0.05 3 1.5 0.5 0.5 2.5 0.17 0.04 4 2.0 0.5 0.5 3.0 0.27 0.08 5 3.0 0.5 0.5 4.0 10 minutes break 8pass chipping 6 0.5 0.5 1.0 2.0 0.23 0.13 7 0.5 0.5 1.5 2.5 0.22 0.14 8 0.5 0.5 2.0 3.0 0.32 0.19 9 1.0 1.0 0.5 2.5 0.38 0.16 10 1.5 0 0.5 2.0 0.23 CrN layer peeling

Table 4

As described above, when the TiAlCrN multilayer thin film having the TiAlN hard coating layer and the TiAlN hard layer added Cr to the surface of the cutting tool or wear resistant tool is deposited at 0.5 μm to 1.5 μm, the wear resistance of the conventional TiAlN thin film is reduced. You can increase it. In order to increase adhesion and improve impact resistance, the metal Cr layer is deposited to a thickness of 0.2 μm to 0.5 μm, and then the CrN thin film is deposited to the outermost area of 0.5 μm to 1.5 μm to increase lubricity. Hard alloys are obtained.

When the present invention is applied to a cutting tool or a wear-resistant tool, it is possible to perform high-speed processing of materials such as aluminum, aluminum alloy, copper, or copper alloy, which are heavily welded, and in particular, the productivity is high due to the excellent cost performance of DLC and diamond tools. Savings can be achieved.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention described in the claims below. You will understand how you can.

Claims (5)

As a multilayer hard thin film for coating aluminum and aluminum alloy or copper and copper alloy processing cutting tools or wear-resistant tool surfaces, a multilayer thin film of TiAlCrN / TiAlN is deposited in a thickness of 0.5 µm-1.5 µm, and a Cr metal layer is deposited thereon. A multilayer rigid thin film, characterized in that the total thin film thickness is 1.0㎛-2.5㎛ by depositing 0.5Nm and CrN thin film 0.5㎛-1.5㎛ as the outermost layer. The multilayer hard thin film according to claim 1, wherein the multilayer hard thin film is deposited on a tool by the UBM method and / or the arc method. The multilayer hard thin film according to claim 1, wherein the multilayer thin film of TiAlN / TiAlCrN is coated with 100-1700 layers by crossing. The multilayer hard film of claim 1, wherein the TiAlCrN thin film is composed of (TiaAlbCrc) N, wherein a + b + c = 1 and c = 5 atomic% -12 atomic%. 5. The multilayer hard thin film according to claim 4, wherein the TiaAlbCrcN coating layer has a growth direction of (200) plane.