KR100239276B1 - Coated hard alloy for a cutting tool or wear resistance tool and a manufacturing method thereof - Google Patents

Abstract

A surface-coated hard alloy is disclosed for cutting tools / abrasion resistant tools that is easy to detect wear and improves high temperature hardness and wear resistance. The coated hard alloy according to the present invention includes a hard coating layer composed of at least one component selected from the group consisting of nitrides and carbonitrides of titanium (Ti), aluminum (Al) and vanadium (V). At this time, content of aluminum (Al) is about 5-25 atomic%, and content of vanadium (V) is about 2-10 atomic%. Preferably, the hard coating layer has a thickness of about 0.5 to 10㎛, the surface of the cutting tool or wear-resistant tool using physical vapor deposition (PVD) or Hollow Cathode Discharge method provided with an ionization enhancement condition Coated on. The coated hard alloy is an intermediate layer provided between the surface of the base material and the hard coated layer and composed of at least one component selected from the group consisting of carbides, nitrides and carbonitrides of titanium (Ti) and having a thickness of about 0.5 to 5 μm. It includes more. In addition, the coated hard alloy further includes an adhesion strengthening layer of titanium (Ti) provided in a thickness of about 0.05 to 1 μm between the surface of the base material and the hard coating layer, or between the surface of the base material and the intermediate layer. .

Description

[Name of invention]

Surface-coated hard alloys for cutting tools and wear resistant tools

Detailed description of the invention

[Purpose of invention]

[Technical field to which the invention belongs and the prior art in that field]

The present invention relates to a surface-coated hard alloy for cutting tools / abrasion resistant tools which is easy to detect the amount of wear and has improved high temperature hardness and wear resistance.

In general, as the mechanical industry, such as the automobile industry, etc. is highly developed, and as a result, the manufacturing process is automated and speeded up, it is essential to increase the life of cutting tools or wear resistant tools widely used in the mechanical industry. In order to increase the life of the cutting or wear resistant tool, the cutting tool or the wear resistant tool should be given excellent high temperature hardness and oxidation resistance. To this end, a coated hard alloy is laminated on the surface of the cutting tool or wear resistant tool.

Typically, cutting tools or wear resistant tools are formed by sintering powder raw materials such as tungsten carbide (WC) based cemented carbide, titanium carbide (TiC) based cermet alloys, ceramics or steel such as high speed steel to form a sintered body. After passing through a conventional ultrasonic cleaning process, it is formed by laminating a hard coat layer on the surface of the sintered body in order to impart wear resistance and impact resistance.

The hard coat layer is formed on the substrate. That is, the hard coat layer is a known coating of at least one layer composed of carbide, nitride, carbonitride, carbonate or aluminum oxide of titanium (Ti), zirconium (Zr) or hafnium (Hf), which is a group IV-A metal. It is formed on the surface of the base material by physical vapor deposition (hereinafter referred to as PVD) or chemical vapor deposition (hereinafter referred to as CVD).

PVD is a thin film deposited on the surface of the base material by sputtering or ion plating, and the hard coating layer formed by the PVD can improve wear resistance without lowering the strength of the base material. It is suitable for cutting applications where strength is required, such as drills, endmills, milling cutters and the like. CVD is a coating of raw material gas on the surface of the base material by injecting the base material and source gas into the reaction vessel, which is blocked from the outside, and controlling the flow rate of the source gas, the flow rate ratio of the individual gases constituting the source gas, and the reaction pressure. High temperature CVD is mainly used for coating of tools. In general, PVD is advantageous over CVD in that the strength of the base material can be easily maintained.

When the surface hard coating layer is formed on the base material of the cutting tool or the wear resistant tool using such known PVD or CVD, the toughness of the base material and the wear resistance of the hard coating layer are combined. Therefore, the cutting tool or the wear resistant tool in which the hard coating layer is laminated has a longer life than the cutting tool or the wear resistant tool in which the hard coating layer is not laminated, shows excellent performance, and improves work efficiency.

Recently, in order to further improve the performance of cutting tools or wear resistant tools, a method of coating carbides, nitrides and carbonitrides of aluminum (Al) with IV-A metal on the surface of the cutting tool or wear resistant tool has been described. It was developed. That is, when carbides, nitrides, and carbonitrides of the Group IV-A metal and aluminum (Al) are coated on the surface of the cutting tool or the wear resistant tool, the high temperature hardness and the oxidation resistance of the coating film are affected by the addition of aluminum (Al). Because of the increase, the life of the cutting tool or the wear resistant tool is extended and the performance is further improved. However, in the case where the carbides, nitrides and carbonitrides of the Group IV-A metal and aluminum (Al) are coated on the surface of the cutting tool or the wear resistant tool, the aluminum (Al) content is less than a predetermined amount. ) Does not show the effect of addition.

Representative examples of carbides, nitrides, and carbonitrides of Group IV-A metals include titanium nitride (TiN), and TiAlN with aluminum (Al) has been put to practical use to increase its high temperature hardness and wear resistance. By the way, when the chemical formula of the aluminum (Al) additive is Ti1-XAlXN, if x is less than 0.25, the addition effect of aluminum (Al) does not appear, and the high temperature hardness and the oxidation resistance of the coating film are increased only when x is 0.25 or more. do. On the other hand, when x is 0.25 or more, the coating film has a dark color such as purple, purple, or black. Therefore, in the case of using a cutting tool or a wear resistant tool coated with a hard coating film, since the amount of wear of the tool is not displayed properly, the degree of wear of the tool cannot be accurately determined, and thus, the optimum replacement time of the tool is missed. Occurred frequently.

Conventional solutions for solving this problem have been disclosed in the reference document “Surface and Coating Technology, 33 (1987, 117-132).” According to the reference, the high temperature of a cutting tool or a wear resistant tool When adding aluminum (Al) which can increase hardness and oxidation resistance, the amount of addition is reduced so that the color of the coating film becomes yellow. At the same time, the amount of aluminum (Al) added is small by adding a small amount of vanadium (V). To minimize the wear resistance improvement effect, TiAlVN was formed by using high speed steel as the base material and by ion plating.

However, in TiAlVN prepared according to the method disclosed in the above reference, the ionization rate of titanium (Ti) and the ionization rate of aluminum (Al) and vanadium (V) are fundamentally different from each other, and the ionization rate of a small amount of additive is titanium (Ti). Since the effect of the small amount of additives is not well seen compared to), there is a problem in that the addition effect of aluminum (Al) and vanadium (V) does not appear and only shows performance similar to that of TiN.

International Publication No. WO 91/05075, filed internationally on September 28, 1990 by Sumitomo Electric Industries, Limited and published on April 18, 1991, has a long history of high temperature cutting. Surface hard members for cutting tools or wear resistant tools have been disclosed that can maintain good cutting performance over a period of time. The surface hard member is formed of at least one component selected from the group consisting of carbides, nitrides and carbonitrides of titanium (Ti), zirconium (Zr) or hafnium (Hf), which are Group IV-A metals, and aluminum (Al). It has a hard coating layer formed. However, in the hard coating layer, since the content of aluminum (Al) is 50 atomic% or less, the above-mentioned problem is caused that the color of the coating film coated on the surface of the cutting tool or the wear resistant tool becomes dark.

[Technical problem to be achieved]

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a surface coating hard alloy for cutting tools / wear resistant tools that can easily detect the amount of wear and improved high temperature hardness and wear resistance.

[Configuration and Function of Invention]

In order to achieve the above object, the present invention, at least one selected from the group consisting of nitrides and carbonitrides of titanium (Ti) and aluminum (Al) and vanadium (V) is applied on the surface of the cutting tool or wear-resistant tool Surface for a cutting tool or abrasion resistant tool, comprising at least one hard coating layer composed of a component, wherein the content of the aluminum (Al) is 5 to 25 atomic% and the content of the vanadium (V) is 2 to 10 atomic%. It provides a coated hard alloy.

Preferably, the hard coat layer has a thickness of about 0.5 to 10 μm.

The coated hard alloy further includes an intermediate layer provided between the surface of the cutting tool or the wear resistant tool and the hard coating layer and composed of at least one component selected from the group consisting of carbides, nitrides, and carbonitrides of titanium (Ti). . Preferably, the intermediate layer has a thickness of about 0.5-5 μm.

In addition, the coated hard alloy may further include a surface of the cutting tool or wear resistant tool in order to improve the degree of engagement between the surface of the cutting tool or wear resistant tool and the hard coating layer or the surface of the cutting tool or wear resistant tool and the intermediate layer. And an adhesion reinforcing layer provided between the hard coating layer or between the surface of the cutting or wear resistant tool and the intermediate layer. Preferably, the adhesion enhancement layer is made of a titanium (Ti) layer and has a thickness of about 0.05 to 1 μm.

As described above, according to the present invention, at least one component selected from the group consisting of nitrides and carbonitrides of titanium (Ti), aluminum (Al) and vanadium (V) on the surface of the cutting tool or the wear resistant tool At least one hard coating layer constituted is applied, and at the same time, the content of aluminum (Al) is limited to 5 to 25 atomic%, and the content of vanadium (V) is limited to 2 to 10 atomic%. As a result, a surface-coated hard alloy for cutting tools or wear-resistant tools with which the amount of wear can be easily detected with the naked eye and improved in high temperature hardness and wear resistance is obtained.

Hereinafter, preferred embodiments of the present invention will be described in detail.

In order to improve the high temperature hardness and oxidation resistance of a cutting tool or abrasion resistant tool, the present invention is made of tungsten carbide (WC) based cemented carbide, titanium carbide (TiC) based cermet alloy, ceramic or high speed steel, such as steel. On the surface of the base material, at least one hard coating layer made of at least one component selected from the group consisting of nitrides and carbonitrides of titanium (Ti), aluminum (Al) and vanadium (V) is provided. Preferably, the hard coat layer is coated on the substrate surface of the cutting tool or wear resistant tool to a thickness of about 0.5 to 10 μm.

At this time, in order to easily detect the wear amount of the cutting tool or the wear resistant tool, the content of aluminum (Al) is reduced so that the color of the coating film is yellow. Preferably, the content of aluminum (Al) is maintained in the range of about 5 to 25 atomic percent. The reason for limiting the content of aluminum (Al) in this range is that when the content of aluminum (Al) is less than about 5 atomic%, the wear resistance improvement effect of the cutting tool or the wear resistant tool does not appear, and when it exceeds 25 atomic%, the wear resistance This is because the improvement is obvious, but the color of the coating shows a dark color of black color, making it difficult to detect the amount of wear of the cutting tool or the wear resistant tool.

When the content of aluminum (Al) exceeds 25 atomic%, the inclined surface of the cutting tool or the wear resistant tool increases the amount of wear. Because, too high Al2O3 exhibits a high hardness at a high temperature and has a tool surface protection function, the degree of oxidation of the inclined surface of the tool cutting the workpiece in frequent contact with the workpiece increases the wear amount of the inclined surface.

On the other hand, a small amount of vanadium (V) is added to compensate for the decrease in the wear resistance improving effect of reducing the content of aluminum (Al). At this time, the content of vanadium (V) is maintained in the range of about 2 to 10 atomic%. The reason for limiting the content of vanadium (V) in this range is that when the content of vanadium (V) is less than about 2 atomic%, the effect of improving the wear resistance of the cutting tool or the wear resistant tool does not appear, and when the content exceeds 10 atomic%, This is because the amount of wear on the free surface of the tool or the wear resistant tool is inferior.

On the other hand, in the present invention, in order to increase the ionization rate of aluminum (Al) and vanadium (V) so that the effect of these small amount additives is well revealed, the hollow cathode discharge method having a high ionization rate (hereinafter referred to as HCD) Add aluminum (Al) and vanadium (V) using. However, the present invention may be carried out using a general PVD method when an apparatus for increasing the ionization rate is installed.

The TiAlV coating method may be performed by forming a molten composite thereof and coating the surface of the base material, or by coating a specific ratio of individual metals. In particular, when titanium alloy Ti6A14V (6 wt% Al, 4 wt% V) having various uses is used as a base material, supply and demand of raw materials can be easily improved, and reliability of thin film composition can be improved. In addition, since the titanium alloy Ti6A14V (6% by weight Al, 4% by weight V) can be mass-produced, there is an advantage that the raw material cost is reduced as compared with the case of custom-made raw materials of a specific composition.

The cutting tool or wear resistant tool produced by the present invention can be multilayered. That is, an intermediate layer of at least one component selected from the group consisting of carbides, nitrides and carbonitrides of titanium (Ti) is provided between the substrate surface of the cutting tool or the wear resistant tool and the hard coat layer. Preferably, the intermediate layer has a thickness of about 0.5-5 μm. Even when the cutting tool or the wear resistant tool is multilayered in this manner, the effect of improving the wear resistance of the hard wood layer finally obtained is not reduced.

The performance of the hard coat coating tool depends largely on the adhesion of the coat layer and the base material as well as the properties of the coat layer itself. Accordingly, in the present invention, an adhesion reinforcing layer is provided between the surface of the tool and the hard coating layer in order to improve the bonding of the surface of the cutting tool or the wear resistant tool with the hard coating layer. Similarly, in order to improve the bonding of the surface of the cutting tool or the wear resistant tool with the intermediate layer, an adhesion enhancing layer is also provided between the surface of the tool and the intermediate layer. Preferably, the adhesion enhancement layer is made of a titanium (Ti) layer, and has a thickness of about 0.05 to 1㎛. By providing such an adhesion reinforcing layer, the adhesion between the thin film and the intermediate layer is increased and the machinability is improved.

In the following, embodiments of the present invention are described in more detail.

EXAMPLE

First, a cemented carbide of grade P30 is prepared as a base material of a cutting tool or wear resistant tool. Next, TiAlVN is coated on the surface of the cemented carbide using equipment capable of performing HCD. That is, using a conventional titanium alloy Ti6Al4V (6% by weight, Al, 4% by weight V) as a melting source, dissolved and evaporated, and ionized, in addition to -100 to -20V range to the coated material under the nitrogen gas Applying a direct current voltage (DC) of TiAlVN on the surface of the cemented carbide to a thickness of about 2㎛.

At this time, between the surface of the cemented carbide and the TiAlVN layer, an intermediate layer composed of at least one component selected from the group consisting of carbides, nitrides, and carbonitrides of titanium (Ti) is appropriately provided within a range of about 0.5 to 5 μm. In addition, in order to improve the bonding between the surface of the cemented carbide and the TiAlVN layer, or the surface of the cemented carbide and the intermediate layer, between the surface of the cemented carbide and the TiAlVN layer, or between the surface of the cemented carbide and the intermediate layer (Ti) An adhesion enhancing layer consisting of a layer is suitably provided within the range of about 0.05 to 1 mu m.

In addition, for comparison, TiN is coated on the surface of the cemented carbide using the same equipment. That is, by using ordinary titanium as a melting source, the solution is evaporated and ionized, and at the same time, TiN is applied on the surface of the cemented carbide by applying a DC voltage in the range of -100 to -20V to the coated material under nitrogen gas. Coating to a thickness of about 2 μm.

In order to evaluate the wear resistance of the TiAlVN coated tool, the TiN coated tool, and the uncoated base material tool obtained through this manufacturing process, the milling abrasion resistance test was conducted as follows.

[Cutting test conditions]

Workpiece: SCM440 (barrel of hardness HB 250; width 150mm, length 265mm)

Cutter: 160 mm diameter, tool shape: SDCN42MT

Cutting speed: 271 m / min (tool speed: 540 RPM)

Feed speed: 0.22 mm / tooth (bed speed 120 mm / min)

Depth of cut: 2.0 mm dry, short cut test

Cutting time: Set the life criterion when the clearance wear level is 0.2mm.

Result: Uncoated P30 cemented carbide tool has a service life of 0.202 mm after two runs. TiN coated tool has a life span of 0.2mm after 7 runs. TiALVN coated tool has a life span of 0.203mm after 15 runs. Accordingly, it can be seen that the TiALVN coated tool has a longer life than the TiN coated tool by more than two times.

In addition, the endurance test was done on the following cutting conditions for the purpose of evaluating toughness.

[Cutting test conditions]

Workpiece: SCM440 (3 sheets of hardness HB 250, 25 mm wide and 265 mm long are separated by 3 mm apart and cut in overlapping form.)

Cutter: 160 mm diameter, tool shape: SDCN42MT

Cutting speed: 126m / min (Tool speed: 250RPM)

Feed speed: 0.18-0.60 mm / tooth (bed speed 45-165 mm / min)

Depth of cut: 2.0 mm dry, short cut test

Cutting time: Measures whether or not it passed in the breakup business after one run. In case of breakage during transport, the breakage is measured by cutting under the same conditions using different inserts.

Result: Uncoated P30 cemented carbide tools pass without damage up to a feed rate of 0.60 mm / tooth. TiN sheathed tool passes without damage up to feed rate of 0.48mm / tooth and breakage occurs at 0.54mm / tooth.

TiAlVN coated tool passes through without damage up to the feed rate of 0.60mm / tooth and shows the same toughness as uncoated cemented carbide. Therefore, TiAlVN coated tools exhibit the same toughness as uncoated tools, and have improved toughness compared to TiN coated tools.

Example 2

First, an evaporation raw material different from the titanium alloy used in Example 1 is prepared. In order to fabricate thin films having different compositional ratios using raw materials having different amounts of aluminum (Al) and vanadium (V), it is most preferable to use raw materials obtained by melt-synthesizing each metal at a predetermined ratio. There is a problem such as rising. Therefore, a raw material is prepared by drilling a hole in titanium (Ti) and inserting a predetermined amount of aluminum (Al) and vanadium (V). Next, the raw materials are dissolved and evaporated and ionized using equipment capable of performing HCD. At the same time, nitrogen is added in the case of nitride, and carbon-containing gas such as methane or acetylene and nitrogen in the case of carbonitride At the same time. Under this condition, an appropriate voltage is applied to the object to be coated to coat the hard coating layer TiAlVN / TiAlVCN to a thickness of about 2 μm.

At this time, between the surface of the cemented carbide and the TiAlVN / TiAlVCN layer, an intermediate layer composed of at least one component selected from the group consisting of carbides, nitrides and carbonitrides of titanium (Ti) is appropriately provided within the range of about 0.5 to 5㎛. . Further, in order to improve the bonding between the surface of the cemented carbide and the TiAlVN / TiAlVCN layer, or the surface of the cemented carbide and the intermediate layer, between the surface of the cemented carbide and the TiAlVN / TiAlVCN layer, or between the surface of the cemented carbide and the intermediate layer An adhesion enhancement layer made of a titanium (Ti) layer is appropriately provided within the range of about 0.05 to 1 mu m.

In order to compare and evaluate the wear resistance of the tool obtained through the manufacturing process, the cutting test was performed in the same manner as the cutting test in Example 1, and the results are shown in Table 1 below. That is, after cutting 15 times, the amount of wear on the clearance surface and the inclined surface of the tool was measured.

As can be seen from Table 1, in Example 2 according to the present invention, even though the distribution of the individual metals of the raw materials is not uniform because the raw material synthesized by melting is not used as a base material, the hard coating according to the present invention. The wear amount of the film shows a large difference compared to the wear amount of the conventional TiN, TiCN thin film, and the tool according to the present invention shows excellent results. Therefore, it can be seen that the production method of the base material has little effect on the effects predicted by the present invention. However, in view of the production of cutting tools or wear-resistant tools having the same performance hundreds to thousands of times, it is necessary to prepare metallurgical melt-synthesized raw materials for the base material used in the production of cutting tools or wear-resistant tools. desirable.

Considering the improvement of the performance by the addition of aluminum (Al) and vanadium (V), the evaluation results of the cutting performance of the hard coating film according to the present invention and TiALV (C) N outside the scope of the present invention, It can be seen that the hard coating film is superior to the comparative tools in terms of the amount of inclined wear of the tool and the amount of wear of the free surface.

On the other hand, the color of the hard coat film, the amount of inclined surface wear and the amount of free surface wear vary depending on the content of aluminum (Al) and vanadium (V). That is, when the content of aluminum (Al) is less than 5 atomic%, there is no effect of improving wear resistance. When the content of aluminum (Al) exceeds 25 atomic%, the wear resistance is good but the appearance of the hard coating film is black. do. Therefore, in the case of using a cutting tool or a wear resistant tool coated with a hard coat film, the amount of wear of the tool is not properly expressed in appearance. Moreover, when content of aluminum (Al) exceeds 25 atomic%, the amount of wear of the inclined surface of a tool will become large.

In addition, vanadium (V) can increase the wear resistance of the cutting tool or the wear resistant tool in a small amount, but when the content is less than 2 atomic%, the addition effect is small, and when the content exceeds 10 atomic%, the amount of free surface wear of the tool is inferior. Become.

Meanwhile, as shown in Comparative Samples 9 and 10 of Table 1, the wear resistance of carbonitride (TiCN) is better than that of nitride (TiN). In this regard, according to the present invention, in the case of the same metal composition, the sample 5 (TiAlVCN) of the present invention prepared by Example 2 had a free surface wear amount of 0.14 mm in 15 cuttings, and the rigid coating layer prepared by Example 1 The abrasion resistance of TiAlVN after cutting 15 times showed better wear resistance than 0.203mm.

In the coating film according to the present invention, when the thickness is so thin that the thickness is 0.5 占 퐉 or less, the effect of improving the wear resistance of the hard coating film becomes small, so that the desired wear resistance cannot be obtained. On the other hand, when the thickness exceeds 10 micrometers, a hard coating film is easy to break and it is difficult to apply to tools. Therefore, the thickness of the hard coat film according to the present invention is preferably limited to about 0.5 to 10㎛.

On the other hand, the cutting tool or wear-resistant tool produced according to the present invention is multilayered by inserting titanium carbide (TiC), titanium nitride (TiN) or titanium carbonitride (TiCN) as an intermediate layer between the hard coat film and the base material. Even in such a case, the abrasion resistance improving effect of the finally obtained hard coat film is not reduced. In addition, in order to enhance the adhesion between the thin film and the base material or between the intermediate layer and the base material, a Ti layer is inserted between them as an adhesion reinforcing layer. As a result, the adhesion of the thin film is increased and the machinability is improved.

[Effects of the Invention]

As described above, according to the present invention, at least one component selected from the group consisting of nitrides and carbonitrides of titanium (Ti), aluminum (Al) and vanadium (V) on the surface of the cutting tool or the wear resistant tool At least one hard coating layer constituted is applied, and at the same time, the amount of the aluminum (Al) is limited to 5 to 25 atomic%, and the content of the vanadium (V) is limited to 2 to 10 atomic%, thereby visually reducing the amount of wear. The surface coating hard alloy for cutting tools or wear resistant tools which can be easily detected and has improved high temperature hardness and wear resistance is obtained.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand that you can.

Claims (7)

It is applied on the surface of a cutting tool or wear resistant tool and consists of one or two or more components selected from the group consisting of nitrides and carbonitrides of titanium (Ti), aluminum (Al) and vanadium (V), and has a thickness of 0.5 to 10 탆. And a hard coating layer having a content of 5 to 25 atomic% and a content of 2 to 10 atomic% of vanadium (V). The method of claim 1, wherein the coated hard alloy is provided between the surface of the cutting tool or the wear resistant tool and one or more components selected from the group consisting of carbides, nitrides and carbonitrides of titanium (Ti). A surface-coated hard alloy for cutting tools or wear resistant tools, further comprising an intermediate layer configured. 3. The surface-coated hard alloy for cutting tools or wear resistant tools according to claim 2, wherein the intermediate layer has a thickness of 0.5 to 5 mu m. The method of claim 1, wherein the coated hard alloy is provided between the surface of the cutting tool or wear resistant tool and the hard coating layer to improve the degree of engagement of the surface of the cutting tool or wear resistant tool with the hard coating layer. A surface-coated hard alloy for cutting tools or wear resistant tools, further comprising a reinforcing layer. 3. The adhesion reinforcing layer according to claim 2, wherein the coated hard alloy is provided between the surface of the cutting tool or the wear resistant tool and the intermediate layer to improve the degree of engagement of the surface of the cutting tool or the wear resistant tool with the intermediate layer. Surface-coated hard alloy for cutting tools or wear-resistant tools further comprising a. 6. The surface-coated hard alloy according to claim 4 or 5, wherein the adhesion reinforcing layer is made of a titanium (Ti) layer. 7. The surface-coated hard alloy for cutting tools or wear resistant tools according to claim 6, wherein the titanium (Ti) layer has a thickness of 0.05 to 1 mu m.