KR101951316B1 - Cutting tools coated with hard film for heat resistant super alloy - Google Patents

Abstract

The present invention relates to a coated sintered alloy for a cutting tool and a cutting tool using the coated sintered alloy, which control components forming the sintered alloy and a microstructure of a binder and deposit coating of thermal resistance and abrasion resistance to be possible to be suitably used for a process of a workpiece having low thermal conductivity, such as Inconel or titanium.

Description

TECHNICAL FIELD [0001] The present invention relates to a cutting tool having a hard coating,

More particularly, the present invention relates to a cutting tool for a hard cutting material having a hard coating layer, and more particularly, to a cutting tool having a hard coating layer formed on the cemented carbide by controlling components constituting the cemented carbide forming the base material of the cutting tool, And a composition thereof, so that it can be suitably used for machining a workpiece having a low thermal conductivity such as inconel or titanium.

As a base material for abrasion-resistant tools and cutting tools used for metal cutting, mainly hard metal (WC-Co alloy), TiC or Ti (C, N) are used as hard materials and Co, Ni and Fe are used as binders Cermet, other ceramics or high-speed steel are used.

The cemented carbide is a composite material in which hard tungsten carbide (WC) particles are dispersed in a binder metal such as cobalt (Co), nickel (Ni) or iron (Fe) excellent in toughness, It is widely used as base metal.

In order to improve the mechanical properties such as abrasion resistance, toughness and high temperature characteristics of the base metal for cutting tools, a grain growth inhibitor such as vanadium carbide (VC) is added to obtain a microstructure, or the concentration of the binder metal on the surface of the sintered body is reduced Micro-organ control such as incubation has been widely used.

On the other hand, when machining hard materials such as Inconel and Ti, the deformation of the tool occurs rapidly during the cutting process due to the low thermal conductivity of the material to be processed, A chip having a tough characteristic is produced, so that the adhesion and detachment due to the chip become serious, and the tool life is remarkably reduced.

In order to improve such a problem and to prolong the life of the cutting tool, it is necessary that the cutting tool itself has excellent plastic deformation resistance and adhesion resistance together with the surface improvement of the edge portion of the cutting tool.

To this end, as disclosed in the following Patent Document, a method of incorporating a component such as ruthenium (Ru) into a binder has been proposed, and a considerable effect has been obtained, but there is much room for improvement.

Korean Patent Publication No. 10-2009-0121351

An object of the present invention is to provide a cutting tool excellent in plastic deformation resistance and adhesive property.

In order to solve the above problems, the present invention provides a cemented carbide base material, comprising: a cemented carbide base material; and an abrasion resistant layer formed on the cemented carbide base material, wherein the cemented carbide base material comprises 70 to 92% by weight of WC, 0.1 to 2.0% by weight of a grain growth inhibitor comprising at least one metal selected from the group consisting of carbides, carbonitrides and mixtures thereof, and 7.0 to 15.0% by weight of at least one binder selected from the group consisting of Co, Ni and Fe, And 0.2 to 2.0% by weight of at least one additive selected from the group consisting of Ru, Gd and Re, the binder including Co, the area ratio of Co to the alpha phase being not less than 70%, and the lattice constant of Co being 3.6 and Å or more, the abrasion resistant layer comprises a top layer formed over said coupling layer, and a lower layer formed on the base material, and bonding tiered formed on the lower layer, the lower layer is a TiC _x N _y (x + y = 1, x > 0, y > 0) layer And, wherein the bond layer, which are sequentially formed on the lower _{layer, Ti 1-a Al a C} x N y O z (0.1≤a≤0.5, x + y + z = 1, x> 0, y> 0 , z > 0) layer, said top layer comprising an alpha-alumina layer having a TC (006) of at least 2.0, expressed in the following formula:

[Formula 1]

TC (hkl) = I (hkl) / Io (hkl) {1 / nSi (hkl) / Io (hkl)} ^-1

(Hkl) = (hkl) reflection intensity, Io (hkl) = according to JCPDS card 46-1212

Standard intensity, n = number of reflections used in the calculation, (hkl) reflections using (012), (104), (110), (006), (113), (024) and (116)

The cutting tool according to the present invention is characterized in that the composition of the hard phase and the binder constituting the cemented carbide as described above is limited and the microstructure of the cobalt constituting the binder is controlled and the structure and composition of the wear resistant layer formed on the cemented carbide By controlling the structure, it is possible to realize improved plastic deformation resistance and resistance to wear when machining hard materials such as inconel (Inconel) and titanium (Ti).

Further, in the cutting tool according to the embodiment of the present invention, by maintaining the surface roughness (Ra) of the abrasion-resistant layer formed on the cutting edge of the cutting tool at 4.0 μm or less, more excellent wear resistance can be obtained.

FIG. 1 is a view for comparing the state of a cutting tool after a workpiece made of Inconel 718 alloy is milled using a cutting tool according to Example 1 and Comparative Example 1 of the present invention.
FIG. 2 is a view for comparing the state of a cutting tool after a workpiece made of a Ti-6Al-4V alloy is milled using a cutting tool according to Example 1 and Comparative Example 1 of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

The cutting tool according to the present invention comprises a cemented carbide base material and an abrasion resistant layer formed on the cemented carbide base material, wherein the cemented carbide base material comprises 70 to 92% by weight of WC and 4 to 5, 6 to 6 0.1 to 2.0% by weight of a grain growth inhibitor comprising at least one metal selected from the group consisting of carbides, carbonitrides and mixtures thereof, 7.0 to 15.0% by weight of at least one binder selected from the group consisting of Co, Ni and Fe, 0.2 to 2.0 wt% of at least one additive selected from the group consisting of Ru, Gd and Re, the binder contains Co, the area ratio of Co to the alpha phase is not less than 70%, the lattice constant of Co is not less than 3.6 Å and wherein the abrasion resistant layer is the lower layer is a TiC _x N _y (x + y = 1, and includes a top layer formed on the coupling-tiered, and the bonding layer formed on the lower layer and this lower layer formed on the base material , x > 0, y > 0) layer, The bonding layer is formed of Ti _1-a Al _a C _x N _y O _z (0.1? A? 0.5, x + y + z = 1, x> 0, y> 0, z> 0) layer, and the upper layer comprises an alpha-alumina layer having a TC (006) of 2.0 or greater, expressed as [Equation 1] below.

[Formula 1]

TC (hkl) = I (hkl) / Io (hkl) {1 / nSi (hkl) / Io (hkl)} ^-1

(Hkl) = (hkl) reflection intensity, Io (hkl) = according to JCPDS card 46-1212

Standard intensity, n = number of reflections used in the calculation, (hkl) reflections using (012), (104), (110), (006), (113), (024) and (116)

If the content of WC is less than 70 wt%, the cutting tool may be deformed quickly due to insufficient heat resistance during high-speed cutting and high-hardness machining. If the WC content exceeds 92 wt%, the cutting tool It may be easily damaged, so that it is preferably 70 to 92% by weight.

If the amount of the grain growth inhibitor is less than 0.1% by weight, the effect of inhibiting the growth of the grain is reduced and the plastic deformation resistance at high temperature is decreased. In this case, the cutting tool is easily deformed at high speed and continuous conditions. The bonding strength between the WC and the binder is low, so that the cracks between the WC and the binder easily occur due to the impact from the outside, which may reduce the tool life. Therefore, the amount of the grain growth inhibitor is preferably 0.1 to 2.0% by weight.

If the total content of Co, Ni and Fe constituting the binder is less than 7.0% by weight, the bonding force between the WC and the grain growth inhibitor becomes weak and the cutting tool is easily damaged. If the content exceeds 15.0% by weight WC and the grain growth inhibitor are excellent, but it is difficult to ensure sufficient abrasion resistance, so that the range of 7.0 to 15.0 wt% is preferable.

When the sum of one or more components selected from among Ru, Gd and Re as additives is less than 0.2% by weight, the effect of strengthening the solid phase in the solid phase is insufficient and the effect of suppressing the heat-resistant microbial property can not be obtained. And toughness is deteriorated. Therefore, it is preferably 0.2 to 2.0% by weight. A more preferable additive content is 1.5 to 2.0% by weight.

Further, as the grain growth inhibitors are Cr ₃ C ₂ 0.45 ~ 0.85 may comprise, by weight%, Cr ₃ when the content of C ₂ 0.45% by weight is less than the insufficient the grain growth inhibiting effect be effective in strength improvements in bond If the content of Cr ₃ C ₂ is more than 0.85% by weight, the effect of inhibiting grain growth occurs sharply and the brittleness of the alloy due to refinement of the WC particles as the hard phase increases.

It is preferable that Co constituting the binder has an area fraction of an alpha phase (HCP structure) having an excellent hardness of 70% or more, and the lattice constant of the binder is preferably 3.6 Å or more. The area fraction of the alpha phase and the lattice of the binder If the constant does not satisfy the above numerical range, it may be difficult to realize sufficient plastic deformation resistance and tack resistance. More preferably, the area fraction of the alpha phase is 72% or more.

The cemented carbide preferably has a saturation magnetization of 100 to 160 G · cm 2 / g. If the saturation magnetization does not satisfy the above range, it may be difficult to realize the mechanical properties required in the present invention.

Further, the cemented carbide may have 39 to 55% of SMS obtained by the following formula

SMS = saturation magnetization value of sintered body x 100 / TMS

(TMS = mass ratio of 2010 × Co)

In addition, the lower layer may preferably comprise a MT-Ti (C, N) layer. Here, the MT-Ti (C, N) layer is a chemical vapor deposition (CVD) process using a gas containing TiCl ₄ gas and CH ₃ CN at a temperature of 750 to 900 ° C. ) Means depositing a layer of titanium carbonitride (TiC _x N _y (x + y = 1, x> 0, y> 0)

If the total thickness of the lower layer is less than 1 mu m, the abrasion resistance of the marginal surface during cutting is insufficient. When the thickness is more than 10 mu m, the MT-Ti (C, N) layer having tensile stress becomes too thick, , Preferably 1 to 10 mu m, and more preferably 2 to 5 mu m.

In addition, a ground layer having a thickness of 0.1 to 1 占 퐉 may be additionally formed between the lower layer and the base metal, optionally including Ti and N.

The layer of Ti _1-a Al _a C _x N _y O _z (0.1? A? 0.5, x + y + z = 1, x> 0, y> 0, z> alpha is a thickness of less than or 0.1㎛ when 1.0㎛ exceeds formed by MT-Ti (C, N) layer and the top layer - it is difficult to impart sufficient adhesive force to the layer of alumina _{(α-Al 2 O 3)} 0.1 ~ 1.0㎛ And a more preferable thickness is 0.2 to 0.6 占 퐉.

The α-Al ₂ O ₃ layer is a stable oxide that does not undergo phase transformation at high temperatures and plays an important role in improving the oxidation resistance. Therefore, the thickness of the α-Al ₂ O ₃ layer should be large enough to cover its role. The toughness is lowered, so that the thickness is preferably 0.5 to 10 mu m.

Further, the alpha-alumina layer (α-Al ₂ O ₃₎ is advantageously a TC (006), the first growth to a 2.0 or higher (006) orientation to obtain the effect according to the invention.

It is preferable that the abrasion-resistant layer has a surface roughness (Ra) of the abrasion-resistant layer formed on the cutting edge of the cutting tool at 4.0 m or less.

At this time, the surface roughness of the wire is based on a measurement made in a region of 1 mm x 20 m using a non-contact surface roughness measuring apparatus.

The numerical range of the surface roughness (Ra) of the wear-resistant layer formed on the cutting tool edge portion may be such that the surface roughness Ra in the above range can be reached through brushing or after-treatment using the medium after forming the wear- have.

In addition, a TiN layer may be further formed on the α-Al ₂ O ₃ layer so as to confirm wear of the cutting tool. In this case, The TiN layer may be removed to minimize damage to the wear layer.

[Example]

The cemented carbide, which is the base material used for the cutting tool according to the embodiment of the present invention, was manufactured through the following process, and cemented carbides according to various compositions and processes were manufactured together for comparison with the base material according to the embodiment of the present invention.

For this purpose, raw material powders for cemented carbide production were first prepared to have the compositions shown in Tables 1 to 4 below. In Table 4 below, Ru + Re + Gd means that the three components are evenly mixed.

division Composition (% by weight) WC particle size
(탆) WC Co Cr ₃ C ₂ Ru Comparative Example 1 89.4 10.0 0.6 0.0 2 to 6 Comparative Example 2 89.4 10.0 0.6 0.0 2 to 6 Comparative Example 3 89.4 10.0 0.6 0.0 2 to 6 Comparative Example 4 87.6 10.0 0.6 1.8 2 to 6 Comparative Example 5 87.6 10.0 0.6 1.8 2 to 6 Comparative Example 6 87.6 10.0 0.6 1.8 2 to 6 Comparative Example 7 89.4 10.0 0.6 0.0 2 to 6 Example 1 87.6 10.0 0.6 1.8 2 to 6 Example 2 87.6 10.0 0.6 1.8 2 to 6 Example 3 87.6 10.0 0.6 1.8 2 to 6 Example 4 87.6 10.0 0.6 1.8 2 to 6 Comparative Example 8 87.3 10.0 0.6 2.1 2 to 6 Comparative Example 9 89.3 10.0 0.6 0.1 2 to 6

division Composition (% by weight) WC particle size
(탆) WC Co Cr ₃ C ₂ Re Comparative Example 10 87.7 10.0 0.5 1.8 2 to 6 Comparative Example 11 87.7 10.0 0.5 1.8 2 to 6 Comparative Example 12 87.7 10.0 0.5 1.8 2 to 6 Comparative Example 13 89.5 10.0 0.5 0.0 2 to 6 Example 5 87.7 10.0 0.5 1.8 2 to 6 Example 6 87.7 10.0 0.5 1.8 2 to 6 Example 7 87.7 10.0 0.5 1.8 2 to 6 Example 8 87.7 10.0 0.5 1.8 2 to 6 Comparative Example 14 87.4 10.0 0.5 2.1 2 to 6 Comparative Example 15 89.4 10.0 0.5 0.1 2 to 6

division Composition (% by weight) WC particle size
(탆) WC Co Cr ₃ C ₂ Gd Comparative Example 16 87.5 10.0 0.7 1.8 2 to 6 Comparative Example 17 87.5 10.0 0.7 1.8 2 to 6 Comparative Example 18 87.5 10.0 0.7 1.8 2 to 6 Comparative Example 19 89.3 10.0 0.7 0.0 2 to 6 Example 9 87.5 10.0 0.7 1.8 2 to 6 Example 10 87.5 10.0 0.7 1.8 2 to 6 Example 11 87.5 10.0 0.7 1.8 2 to 6 Example 12 87.5 10.0 0.7 1.8 2 to 6 Comparative Example 20 87.2 10.0 0.7 2.1 2 to 6 Comparative Example 21 89.2 10.0 0.7 0.1 2 to 6

division Composition (% by weight) WC particle size
(탆) WC Co Cr ₃ C ₂ Ru + Re + Gd Comparative Example 22 87.5 10.0 0.7 1.8 2 to 6 Comparative Example 23 87.5 10.0 0.7 1.8 2 to 6 Comparative Example 24 87.5 10.0 0.7 1.8 2 to 6 Comparative Example 25 89.3 10.0 0.7 0.0 2 to 6 Example 11 87.5 10.0 0.7 1.8 2 to 6 Example 12 87.5 10.0 0.7 1.8 2 to 6 Example 13 87.5 10.0 0.7 1.8 2 to 6 Example 14 87.5 10.0 0.7 1.8 2 to 6 Comparative Example 26 87.2 10.0 0.7 2.1 2 to 6 Comparative Example 27 89.2 10.0 0.7 0.1 2 to 6

The cemented carbide balls and the organic solvent were added to the raw material powder prepared as described above, followed by mixing and grinding for 13 hours to obtain a mixed powder. The obtained mixed powder was pressed through a molding die of RPMT1204-MF at a pressure of 2 ton / cm2 to prepare a molded article.

Next, a dewaxing process is performed at 600 ° C. to remove the organic binder component introduced in the process of forming the molded product, sintering the product in an inert gas atmosphere for 1 to 2 hours, The sintering process was carried out by a cooling method after the cooling rate was cooled. The following Tables 5 to 8 show the manufacturing process conditions of each of the Examples and Comparative Examples.

division Sintering temperature (℃) Cooling speed (° C / min) Comparative Example 1 1380 3 Comparative Example 2 1380 5 Comparative Example 3 1380 7 Comparative Example 4 1420 3 Comparative Example 5 1420 5 Comparative Example 6 1420 7 Comparative Example 7 1500 7 Example 1 1500 3 Example 2 1500 5 Example 3 1500 7 Example 4 1500 10 Comparative Example 8 1500 10 Comparative Example 9 1500 10

division Sintering temperature (℃) Cooling speed (° C / min) Comparative Example 10 1420 3 Comparative Example 11 1420 5 Comparative Example 12 1420 7 Comparative Example 13 1500 7 Example 5 1500 3 Example 6 1500 5 Example 7 1500 7 Example 8 1500 10 Comparative Example 14 1500 10 Comparative Example 15 1500 10

division Sintering temperature (℃) Cooling speed (° C / min) Comparative Example 16 1420 3 Comparative Example 17 1420 5 Comparative Example 18 1420 7 Comparative Example 19 1500 7 Example 9 1500 3 Example 10 1500 5 Example 11 1500 7 Example 12 1500 10 Comparative Example 20 1500 10 Comparative Example 21 1500 10

division Sintering temperature (℃) Cooling speed (° C / min) Comparative Example 22 1420 3 Comparative Example 23 1420 5 Comparative Example 24 1420 7 Comparative Example 25 1500 7 Example 11 1500 3 Example 12 1500 5 Example 13 1500 7 Example 14 1500 10 Comparative Example 26 1500 10 Comparative Example 27 1500 10

Electron Backscatter Diffraction (EBSD) analysis was performed to analyze the microstructure of the binder of the cemented carbide prepared according to the Examples and Comparative Examples of the present invention.

division Saturation magnetization
(G · cm 2 / g) SMS
(%) Alpha Co fraction
(%) Co lattice constant
(A) Comparative Example 1 184.0 80.0 71.0 3.5831 Comparative Example 2 180.0 78.0 70.8 3.5844 Comparative Example 3 175.0 77.0 71.2 3.5892 Comparative Example 4 168.0 65.0 71.2 3.5900 Comparative Example 5 164.0 62.0 71.4 3.5914 Comparative Example 6 162.0 60.0 71.7 3.5917 Comparative Example 7 178.0 77.5 71.0 3.5890 Example 1 154.0 52.0 72.2 3.6021 Example 2 135.0 48.0 72.3 3.6067 Example 3 125.0 46.0 72.7 3.6107 Example 4 115.0 40.0 73.6 3.6122 Comparative Example 8 112.0 39.5 73.7 3.6130 Comparative Example 9 170.0 77.5 71.3 3.5891

division Saturation magnetization
(G · cm 2 / g) SMS
(%) Alpha Co fraction
(%) Co lattice constant
(A) Comparative Example 10 169.0 65.3 71.0 3.5847 Comparative Example 11 167.0 62.1 71.3 3.5910 Comparative Example 12 163.0 60.7 71.6 3.5912 Comparative Example 13 178.0 77.5 71.0 3.5890 Example 5 155.0 52.6 72.2 3.6018 Example 6 138.0 48.2 72.2 3.6041 Example 7 128.0 47.0 72.4 3.6100 Example 8 116.0 41.5 73.3 3.6119 Comparative Example 14 115.0 40.6 72.9 3.6127 Comparative Example 15 172.0 78.1 71.0 3.5888

division Saturation magnetization
(G · cm 2 / g) SMS
(%) Alpha Co fraction
(%) Co lattice constant
(A) Comparative Example 16 170.0 66.6 71.2 3.5851 Comparative Example 17 166.0 64.1 71.4 3.5923 Comparative Example 18 161.0 59.9 71.7 3.5941 Comparative Example 19 178.0 77.5 71.0 3.5890 Example 9 155.0 52.2 72.0 3.6000 Example 10 136.0 48.1 72.3 3.6067 Example 11 124.0 45.9 72.7 3.6154 Example 12 114.0 39.4 73.6 3.6157 Comparative Example 20 116.0 41.6 73.7 3.6181 Comparative Example 21 171.0 77.7 71.1 3.5900

division Saturation magnetization
(G · cm 2 / g) SMS
(%) Alpha Co fraction
(%) Co lattice constant
(A) Comparative Example 22 166.0 64.0 71.0 3.5878 Comparative Example 23 163.0 61.5 70.0 3.5904 Comparative Example 24 161.0 59.8 71.7 3.5930 Comparative Example 25 178.0 77.5 71.0 3.5890 Example 11 154.0 52.0 72.1 3.6031 Example 12 135.0 48.0 72.6 3.6110 Example 13 125.0 46.0 73.0 3.6139 Example 14 115.0 40.0 73.6 3.6148 Comparative Example 26 112.0 39.5 73.9 3.6151 Comparative Example 27 170.0 77.5 71.1 3.5931

As shown in Tables 9 to 12, in the case of the cemented carbide according to the embodiment of the present invention, the alpha phase ratio of Co was 72% or more. In contrast, Comparative Examples 1 to 7, 9 to 13, 15 to 19, 21 to 25 and 27 showed that the proportion of alpha phase in Co was less than 72%.

In addition, in the case of the cemented carbide according to the embodiment of the present invention, the lattice constant of Co is not less than 3.6 Å, but in the case of the comparative example, all the values except for Comparative Examples 8, 14, 20 and 26 are values less than 3.6 Å Respectively.

In the case of the cemented carbide according to the embodiment of the present invention, SMS (%) is in the range of 39 to 55%, but in the case of the comparative example, all of the values except for Comparative Examples 8, 14, 20 and 26 are values Respectively.

On the other hand, Comparative Examples 8, 14, 20 and 26 differ from the cemented carbide manufactured according to the embodiments of the present invention in that the additive content exceeds 2.0% by weight.

A hard coating was formed on the surface of the insert with the cemented carbide manufactured according to the examples and comparative examples of the present invention by the following process.

The MT-TiCN layer with a thickness of 3 μm was coated on the cemented carbide cutting insert by using MT-CVD technique using TiCl ₄ , H ₂ , N ₂ , CH ₃ CN and HCl in a coating furnace at 850 ° C.

In the same coating cycle, _{AlCl 3, TiCl 4, N 2} , H 2, CH 4 and in 1005 ℃ of the plate thickness of about 0.5㎛ Ti1 _-a Al using _{CO a C x N y O z} (0.1≤a≤0.5 , x + y + z = 1, x> 0, y> 0, z> 0).

The specific process conditions at each deposition step are shown in Table 13 below.

step MT-TiCN _{Ti1 -a Al a C x N y} O z alpha -Al ₂ O ₃ TiCl ₄ 1 to 5% 1.5 to 2% - N ₂ 0 to 10% 2 to 10% - CH ₄ - 2% - CO ₂ - 0 to 1% 3.5% CO 0 to 3% 1.5% 0 to 2% AlCl ₃ - 2 to 4% 2.5% H ₂ S - - 0.5 to 2% HCl 1 to 3% - 1 to 3% CH ₃ CN 0.5 to 2% - - H ₂ Remainder Remainder Remainder pressure 8,000 Pa 10,000 Pa 6,000 Pa Temperature 880 ℃ 1,010 ° C 1,010 ° C time 3hr 0.5 hr 2 hr

After the formation of the hard coating, the surface roughness (Ra) of the wear resistant layer formed on the cutting edge of the cutting tool was adjusted to 4.0 m or less through post treatment.

The abrasion resistance of the insert with the hard coating was evaluated under the following cutting conditions.

- Machining method: Milling

- Workpiece: Inconel 718

- Vc (cutting speed): 30 mm / min

- fn (feed rate): 0.18 mm / min

- ap (infeed depth): 0.8mm

- dry / wet: wet

- Machining method: Milling

- Workpiece: Ti-6Al-4V alloy

- Vc (cutting speed): 40 mm / min

- fn (feed rate): 0.18 mm / min

- ap (infeed depth): 1.2mm

- dry / wet: wet

FIG. 1 is a graph comparing the state of a cutting tool after machining a workpiece made of Inconel 718 alloy with a cutting tool according to Example 1 of the present invention and Comparative Example 1, and FIG. 2 is a graph showing the state of a cutting tool made of a Ti-6Al- The workpiece is compared with the state of the cutting tool according to the first embodiment and the first comparative example of the present invention.

As can be seen from FIGS. 1 and 2, the cutting tool according to the comparative example shows much breakage at the time of machining, but the cutting tool according to the embodiment of the present invention has a better machining condition than the comparative example, 718 and Ti-6Al-4V alloys, which have a low thermal conductivity.

Tables 14 to 17 below summarize the results of the cutting test of the hard coated insert prepared according to Examples and Comparative Examples of the present invention.

division Tool life Ti-6Al-4V
(Processing time, minute) Tool life Inconel 718
(Processing time, minute) Comparative Example 1 15 minutes 10 minutes Comparative Example 2 16 minutes 11 minutes Comparative Example 3 19 minutes 13 minutes Comparative Example 4 20 minutes 17 minutes Comparative Example 5 23 minutes 18 minutes Comparative Example 6 26 minutes 20 minutes Comparative Example 7 19 minutes 12 minutes Example 1 30 minutes 27 minutes Example 2 37 minutes 34 minutes Example 3 45 minutes 41 minutes Example 4 50 minutes 43 minutes Comparative Example 8 25 minutes 17 minutes Comparative Example 9 20 minutes 15 minutes

division Tool life Ti-6Al-4V
(Processing time, minute) Tool life Inconel 718
(Processing time, minute) Comparative Example 10 19 minutes 15 minutes Comparative Example 11 24 minutes 19 minutes Comparative Example 12 25 minutes 15 minutes Comparative Example 13 19 minutes 12 minutes Example 5 31 minutes 25 minutes Example 6 33 minutes 33 minutes Example 7 41 minutes 40 minutes Example 8 50 minutes 41 minutes Comparative Example 14 23 minutes 15 minutes Comparative Example 15 17 minutes 12 minutes

division Tool life Ti-6Al-4V
(Processing time, minute) Tool life Inconel 718
(Processing time, minute) Comparative Example 16 19 minutes 12 minutes Comparative Example 17 24 minutes 19 minutes Comparative Example 18 25 minutes 20 minutes Comparative Example 19 19 minutes 12 minutes Example 9 31 minutes 30 minutes Example 10 35 minutes 33 minutes Example 11 44 minutes 39 minutes Example 12 51 minutes 47 minutes Comparative Example 20 22 minutes 13 minutes Comparative Example 21 17 minutes 10 minutes

division Tool life Ti-6Al-4V
(Processing time, minute) Tool life Inconel 718
(Processing time, minute) Comparative Example 22 21 minutes 17 minutes Comparative Example 23 22 minutes 18 minutes Comparative Example 24 26 minutes 20 minutes Comparative Example 25 19 minutes 12 minutes Example 11 31 minutes 28 minutes Example 12 35 minutes 35 minutes Example 13 45 minutes 40 minutes Example 14 51 minutes 42 minutes Comparative Example 26 26 minutes 15 minutes Comparative Example 27 19 minutes 12 minutes

As can be seen in Tables 14 to 17, the cutting tool made of the cemented carbide manufactured according to the embodiment of the present invention exhibited remarkably improved tool life as compared with the cutting tool made of the cemented carbide manufactured according to the comparative example.

Claims (7)

A cemented carbide base material and an abrasion resistant layer formed on the cemented carbide base material,
Wherein the cemented carbide base material comprises 70 to 92% by weight of WC and at least one of a carbide, a carbonitride or a mixture of at least one metal selected from Group 4, Group 5 and Group 6 metals in the periodic table excluding W, 0.1 to 2.0% by weight of a binder, 7.0 to 15.0% by weight of at least one binder selected from the group consisting of Co, Ni and Fe and 0.2 to 2.0% by weight of at least one additive selected from Ru, Gd and Re, Wherein the area ratio of the Co phase to the alpha phase is not less than 70%, the lattice constant of the Co is not less than 3.6 A,
Wherein the abrasion resistant layer comprises a lower layer formed on the base material, a bonding layer formed on the lower layer, and an upper layer formed on the bonding layer,
Wherein the lower layer comprises a layer of TiC _x N _y (x + y = 1, x> 0, y> 0)
The bond layer, which are sequentially formed on the lower _{layer, Ti 1-a Al a C} x N y O z (0.1≤a≤0.5, x + y + z = 1, x> 0, y> 0, z > 0) layer,
Wherein the upper layer comprises an alpha-alumina layer having a TC (006) of 2.0 or greater as represented by the following formula (1).
[Formula 1]
TC (hkl) = I (hkl) / Io (hkl) {1 / nSi (hkl) / Io (hkl)} ^-1
(Hkl) = (hkl) reflection intensity, Io (hkl) = according to JCPDS card 46-1212
Standard intensity, n = number of reflections used in the calculation, (hkl) reflections using (012), (104), (110), (006), (113), (024) and (116) The method according to claim 1,
Wherein the grain growth inhibitor comprises 0.45 to 0.85% by weight of Cr ₃ C ₂ . The method according to claim 1,
And the saturation magnetization of the cutting tool is 100 to 160 G · cm 2 / g. The method according to claim 1,
And the area ratio of the alpha phase of the Co is 72% or more. The method according to claim 1,
Characterized in that the SMS of the cemented carbide is between 39 and 55%. The method according to claim 1,
Wherein the abrasion resistant layer has a surface roughness of 4.0 탆 or less. The method according to claim 1,
Further comprising a TiN layer on top of the alpha-alumina layer, wherein the TiN layer is removed from the tin section.

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