JP7069984B2 - Cover cutting tool - Google Patents

Description

The present invention relates to a coated cutting tool.

Conventionally, cutting tools using materials such as cemented carbide and cBN sintered bodies have been widely used for cutting steel and the like. Among them, surface-coated cutting tools containing one or more hard coating film layers such as TiN layer, TiAlN layer, and AlN layer on the surface of the cemented carbide substrate are used for various machining due to their high versatility. Has been done.

Among the hard coating film layers, the AlN layer has high thermal conductivity and is therefore excellent in heat dissipation. Further, the AlN layer becomes alumina when the temperature becomes high due to cutting, so that the heat resistance can be improved and the welding resistance can also be improved.

For example, in Patent Document 1, any of (Ti, Al), (Ti, Al, Si), or (Ti, Si) nitride, carbon dioxide, or nitrogen is used as an abrasion resistant layer on the surface of the base material. A coated cutting tool made of an oxide or a carbon dioxide oxide and having a hexagonal crystal structure composed of an Al nitride, a carbon nitride, a nitrogen oxide or a carbon dioxide oxide as the outermost layer has been proposed.

Japanese Unexamined Patent Publication No. 2005-2711133

In order to increase the machining efficiency, the cutting conditions tend to be stricter than before, and it is required to extend the tool life more than before. Especially in high-speed machining, the coating layer on the cutting edge may be decomposed and oxidized due to heat generated during cutting. Further, peeling of the coating layer occurs due to welding of the work material to the coating cutting tool. Although the AlN layer is effective as a coating layer, it has low hardness and insufficient wear resistance. Therefore, for example, a coated cutting tool having an AlN layer as a coated layer, such as the coated cutting tool of Patent Document 1, has a problem that the tool life cannot be extended because the wear resistance is inferior.

The present invention has been made to solve the above-mentioned problems. That is, an object of the present invention is to provide a coated cutting tool having excellent wear resistance and welding resistance. Another object of the present invention is to provide a coated cutting tool that can be machined for a long period of time.

The present inventors have conducted research on extending the tool life of a coated cutting tool. The present inventors have found that the wear resistance and welding resistance of a coated cutting tool can be improved by the following configurations. As a result, the tool life of the coated cutting tool could be extended.

That is, the gist of the present invention is as follows.

(1) A coating cutting tool including a substrate and a coating layer formed on the substrate.
The covering layer includes a lower layer and an upper layer formed on the lower layer.
The lower layer has an average thickness of 0.2 μm or more and 5.0 μm or less, and the following formula (1):
(Ti _1-x Al _x ) N (1)
(In the formula, x indicates the atomic ratio of the Al element to the total of the Ti element and the Al element, and satisfies 0.3 ≦ x ≦ 0.7.)
Consists of a composite compound layer having a composition represented by
The upper layer is composed of an AlN layer having an average thickness of 1.5 μm or more and 6.0 μm or less.
The ratio of the diffraction peak intensity I _h (002) of the hexagonal crystal (002) plane to the diffraction peak intensity I _h (100) of the hexagonal crystal (100) plane by the X-ray diffraction method of the upper layer [I _h (002) / I _h (100)] is 5.0 or more, a coated cutting tool.

(2) The ratio of the diffraction peak intensity I _c (111) of the cubic (111) plane to the diffraction peak intensity I _h (100) of the hexagonal (100) plane by the X-ray diffraction method of the upper layer [I _c ( 111) / I _h (100)] is 0.5 or more and 5.0 or less, the covering cutting tool of (1).

(3) The coating cutting tool according to (1) or (2), wherein the average particle size of the particles constituting the upper layer is 0.1 μm or more and 1.0 μm or less.

(4) The coating cutting tool according to any one of (1) to (3), wherein the average thickness of the entire coating layer is 2.0 μm or more and 7.0 μm or less.

(5) The coated cutting tool according to any one of (1) to (4), wherein the base material is any of cemented carbide, cermet, ceramics, or a cubic boron nitride sintered body.

According to the present invention, it is possible to provide a coated cutting tool having excellent wear resistance and welding resistance. Further, according to the present invention, it is possible to provide a coated cutting tool that can be machined for a long period of time.

It is an example of the schematic diagram of the cross-sectional structure of the covering cutting tool of this invention.

The coated cutting tool of the present invention includes a base material and a coated layer formed on the base material. The covering layer includes a lower layer and an upper layer formed on the lower layer. The upper layer is composed of an AlN layer. The coated cutting tool of the present invention is superior in wear resistance and welding resistance to the conventional coated cutting tool by controlling the orientation of the upper layer (AlN layer). Since the coated cutting tool of the present invention is excellent in wear resistance and welding resistance, it can be used for machining for a long period of time.

The coated cutting tool of the present invention includes a base material.

The base material in the present invention is not particularly limited, but a base material used as a base material for a coated cutting tool can be used. Specifically, as the base material in the present invention, for example, any one selected from cemented carbide, cermet, ceramics and cubic boron nitride sintered body can be used. Among these, it is preferable to use any one selected from cemented carbide, cermet, ceramics and cubic boron nitride sintered body as the base material of the coated cutting tool. This is because cemented carbide, cermet, ceramics and cubic boron nitride sintered body are excellent in wear resistance and fracture resistance.

The coating layer of the coating cutting tool of the present invention includes a lower layer formed on the surface of the base material.

The lower layer of the coated cutting tool of the present invention is composed of a composite compound layer having a composition represented by the following formula (1).
(Ti _1-x Al _x ) N equation (1)
(In the formula, x indicates the atomic ratio of the Al element to the total of the Ti element and the Al element, and x satisfies 0.3 ≦ x ≦ 0.7.)

In the present specification, when M and L are arbitrary metal elements and the nitride is expressed as (M _a L _b ) N, the atomic ratio of the M element to the entire metal element is the atomic ratio of the a and L elements. Means that is b. For example, (Ti _0.33 Al _0.67 ) N means that the atomic ratio of the Ti element to the total metal element is 0.33 and the atomic ratio of the Al element to the total metal element is 0.67. .. That is, (Ti _0.33 Al _0.67 ) N means that the amount of Ti element is 33 atomic% with respect to the total metal element, and the amount of Al element is 67 atomic% with respect to the total metal element.

In the coated cutting tool of the present invention, in order to orient the AlN layer of the upper layer described later on the c-axis, the lower layer needs to be (Ti _1-x Al _x ) N represented by the above formula (1). Is. By setting the Al content to 30 atomic% or more (x ≧ 0.3) in the lower layer, the adhesion to the substrate is excellent and the fracture resistance of the coated cutting tool can be improved. Further, by setting the Al content in the lower layer to 70 atomic% or less (x ≦ 0.3), it is possible to suppress the formation of hexagonal crystals in the lower layer and suppress the decrease in hardness of the coating layer. .. As a result, a coated cutting tool having excellent wear resistance can be obtained.

The lower layer of the coated cutting tool of the present invention has an average thickness of 0.2 μm or more and 5.0 μm or less, preferably 0.2 μm or more and 2.0 μm or less. The method of measuring the average thickness will be described later.

When the average thickness of the lower layer is 0.2 μm or less, it becomes difficult to orient the AlN layer of the upper layer, which will be described later, on the c-axis, so that the wear resistance and welding resistance of the coated cutting tool are lowered. .. Further, when the average thickness of the lower layer is 5.0 μm or more, it is easy to peel off, so that the chipping resistance of the coated cutting tool is lowered.

The coating layer of the coated cutting tool of the present invention includes an upper layer formed on the lower layer (opposite to the base material).

The upper layer of the coated cutting tool of the present invention is composed of an AlN layer having an average thickness of 1.5 μm or more and 6.0 μm or less, preferably 1.8 μm or more and 5.8 μm or less. The "AlN layer" is a layer made of only Al and N, excluding impurities that are inevitably mixed.

The ratio of the diffraction peak intensity I _h (002) of the hexagonal (002) plane to the diffraction peak intensity I _h (100) of the hexagonal (100) plane by the X-ray diffraction method in the upper layer of the coated cutting tool of the present invention [ I _h (002) / I _h (100)] (hereinafter, may be simply referred to as “raction peak intensity ratio [I _h (002) / I _h (100)]”) is preferably 5.0 or more. Is 5.2 or more, more preferably 12.0 or more.

In the coated cutting tool of the present invention, the ratio of diffraction peak intensities [I _h (002) / I _h (100)] is 5.0 or more, preferably 5.2 or more, more preferably 12 in the upper AlN layer. When it is 0.0 or more, the abundance ratio of crystals oriented on the c-axis is high. As a result, it is possible to obtain a coated cutting tool having a coated layer having excellent wear resistance and welding resistance.

The following reasoning can be considered as the reason why the wear resistance and the welding resistance are excellent when the abundance ratio of the crystals oriented on the c-axis is large in the AlN layer. That is, in the hexagonal AlN layer, the slip direction is in the ab plane. Therefore, it is considered that by orienting the AlN layer on the c-axis, the AlN layer is less likely to be distorted and the hardness is improved. As a result, the obtained coating layer is considered to have excellent wear resistance. Further, by orienting the AlN layer on the c-axis, the outermost surface becomes a dense surface, so that the chemical reactivity between Al and the work material is lowered (affinity is lowered), so that the welding resistance is excellent. it is conceivable that. However, the present invention is not bound by this reasoning.

In the coated cutting tool of the present invention, the ratio of the diffraction peak intensity I _c (111) of the cubic (111) plane to the diffraction peak intensity I _h (100) of the hexagonal (100) plane by the X-ray diffraction method of the upper layer. [I _c (111) / I _h (100)] (hereinafter, may be simply referred to as “ratio of diffraction peak intensity [I _c (111) / I _h (100)]”) is 0.5 or more and 5 It is preferably 0.0 or less, and preferably 0.7 or more and 4.5 or less.

The ratio [I _c (111) / I _h (100)] of the diffraction peak intensity of the upper layer (AlN layer) is within a predetermined range, that the upper layer has a hexagonal AlN and a cubic AlN. Means that is included. When the AlN layer (upper layer) of the coated cutting tool of the present invention contains cubic AlN in addition to hexagonal AlN, the hardness is further improved and a coated cutting tool having excellent wear resistance can be obtained. can.

When the ratio of diffraction peak intensities of the AlN layer [I _c (111) / I _h (100)] is 0.5 or more, the inclusion of cubic crystals increases the hardness and thus wear resistance. Excellent for. On the other hand, it is difficult in terms of manufacturing technique to increase the ratio of the diffraction peak intensity of the cubic crystal to the hexagonal crystal of the AlN layer to exceed 5.0. Therefore, from the viewpoint of manufacturing technology, the upper limit of the ratio of the diffraction peak intensity of the cubic crystal to the hexagonal crystal of the AlN layer can be set to 5.0.

The upper layer of the coated cutting tool of the present invention has an average thickness of 1.5 μm or more and 6.0 μm or less, preferably 1.8 μm or more and 5.8 μm or less.

When the average thickness of the upper layer is 1.5 μm or less, it becomes difficult to orient the AlN layer of the upper layer described later on the c-axis, so that the wear resistance and welding resistance of the coated cutting tool are lowered. .. Further, when the average thickness of the lower layer is 6.0 μm or more, it is easy to peel off, so that the chipping resistance of the coated cutting tool is lowered.

In the coated cutting tool of the present invention, the average particle size of the particles constituting the upper layer is preferably 0.1 μm or more and 1.0 μm or less, and more preferably 0.2 μm or more and 0.95 μm or less.

In the coated cutting tool of the present invention, when the average particle size of the particles constituting the upper layer is 0.1 μm or more, it is possible to suppress the particles from falling off during the cutting process. Therefore, when the average particle size of the particles constituting the upper layer is 0.1 μm or more, the wear resistance can be improved. On the other hand, when the average particle size of the particles constituting the upper layer is 1.0 μm or less, it is possible to suppress the cracks generated during processing toward the base material from extending toward the base material, and thus withstand resistance. The defect can be improved.

The average thickness of the entire coating layer (lower layer and upper layer) in the coating cutting tool of the present invention is preferably 2.0 μm or more and 7.0 μm or less, and preferably 3.0 μm or more and 6.8 μm or less. .. If the average thickness of the coating layer is less than 2.0 μm, the wear resistance of the coating cutting tool tends to decrease. If the average thickness of the coating layer exceeds 7.0 μm, the fracture resistance of the coating cutting tool tends to decrease.

The method for manufacturing a coated layer in the coated cutting tool of the present invention is not particularly limited as long as the configuration of the coated cutting tool can be achieved. For example, the coating layer can be produced by a physical vapor deposition method selected from an ion plating method, an arc ion plating method, a sputtering method, an ion mixing method, and the like. In particular, the coating layer formed by the arc ion plating method has high adhesion to the substrate. Therefore, it is preferable to manufacture the coating layer by the arc ion plating method.

The method for manufacturing the coated cutting tool of the present invention will be described with reference to an example performed by the arc ion plating method.

First, the base material processed into a tool shape is placed in the reaction vessel of the physical vapor deposition apparatus. Next, the inside of the reaction vessel is evacuated until the pressure becomes 1 × 10 ⁻² Pa or less. After evacuation, the substrate is heated to 200 ° C. to 800 ° C. with a heater in the reaction vessel. After heating, Ar gas is introduced into the reaction vessel to set the pressure to 0.5 Pa to 5.0 Pa. A bias voltage of −200 V to −1000 V is applied to the substrate in an Ar gas atmosphere with a pressure of 0.5 Pa to 5.0 Pa. A current of 5A to 20A is passed through the tungsten filament in the reaction vessel. As a result, the surface of the base material can be ion bombarded with Ar gas. After the surface of the substrate is ion bombarded, the inside of the reaction vessel is evacuated until the pressure becomes 1 × 10 ⁻² Pa or less.

Next, a composite compound layer having a composition represented by (Ti _1-x Al _x ) N is formed as a lower layer on the surface of the base material. Specifically, first, after ion bombardment treatment and vacuuming, a reaction gas such as nitrogen gas is introduced into the reaction vessel. The pressure in the reaction vessel is set to 0.5 Pa to 5.0 Pa, and a bias voltage of −10 V to −150 V is applied to the substrate. By evaporating the metal evaporation source (TiAl evaporation source) corresponding to the metal component of the lower layer by arc discharge, the lower layer of (Ti _1-x Al _x ) N can be formed on the surface of the base material. The arc current at the time of arc discharge is preferably 100 A to 200 A. Further, the temperature of the base material when forming the lower layer is preferably 200 ° C. to 600 ° C.

After forming the lower layer, the upper layer (AlN layer) is formed. Specifically, after the ion bombardment treatment or after forming the lower layer, the inside of the reaction vessel is evacuated and the temperature of the base material is heated to 350 ° C. to 450 ° C. (deposition temperature). Then, nitrogen gas is introduced into the reaction vessel. As a result, the pressure in the reaction vessel is set to 2.0 Pa to 5.0 Pa, and a bias voltage of -60 V to -40 V is applied to the substrate. An upper layer can be formed on the surface of the lower layer by evaporating a metal evaporation source made of Al by an arc discharge having an arc current of 100 A to 150 A.

When forming the upper layer, the lower the film formation temperature, the larger I _h (002) tends to be. Further, the higher the bias voltage applied to the substrate, the larger I _h (002) tends to be. Further, the lower the arc discharge current, the larger I _h (002) tends to be. By adjusting these conditions, the ratio of diffraction peak intensities [I _h (002) / I _h (100)] can be set within a predetermined range.

The lower the temperature at the start of film formation of the upper layer, the larger the average particle size of the upper layer tends to be. Therefore, in order to control the particle size within a predetermined average particle size range, it is preferable to start the film formation of the upper layer within the above-mentioned film formation temperature range.

When the upper layer is formed by arc discharge, the temperature of the base material is lowered (cooled) with the temperature at the start of film formation as the peak temperature. During this cooling, if the cooling rate of the temperature of the substrate is increased to exceed 20 ° C./hour, the proportion of cubic crystals in the AlN layer increases. However, if the cooling rate of the temperature of the substrate is increased to more than 50 ° C./hour, the film forming rate becomes slow, which is not beneficial in manufacturing. Therefore, it is preferable to set the cooling rate of the temperature of the base material to 20 ° C./hour or more and 50 ° C./hour or less.

The thickness of each layer (lower layer and upper layer) constituting the coating layer can be measured by observing the cross-sectional structure of the coating cutting tool. For example, the thickness of each layer constituting the coating layer can be measured using an optical microscope, a scanning electron microscope (SEM), a transmission electron microscope (TEM), or the like.

The average thickness of each layer constituting the coating layer can be obtained as follows. That is, the cross section of the coated cutting tool is observed at three or more points (for example, three points) by SEM or the like in the vicinity of a position of 50 μm from the cutting edge of the surface facing the metal evaporation source toward the center of the surface. From this observed cross section, the thickness of each layer is measured. A known image processing software or the like can be used to measure the thickness based on the observed cross-sectional image. By calculating the average value of the thickness of each layer measured in this way, the average thickness can be obtained.

The composition of each layer constituting the coating layer can be measured from the cross-sectional structure of the coating cutting tool using a measuring device such as an energy dispersive X-ray analyzer (EDS) and a wavelength dispersive X-ray analyzer (WDS). can.

For the upper layer of the present invention, the peak intensity I _h (100) on the hexagonal (100) plane, the diffraction peak intensity I _h (002) on the hexagonal (002) plane, and the diffraction peak intensity I _c on the cubic (111) plane. (111) can be measured using a commercially available X-ray diffractometer. For the measurement of the peak intensities I _h (100), I _h (002) and I _c (111), for example, an X-ray diffractometer RINT TTR III manufactured by Rigaku Co., Ltd. can be used. Further, for the measurement, the measurement by the X-ray diffraction method of the 2θ / θ concentrated optical system using Cu—Kα rays can be used. The measurement conditions of the X-ray diffraction method are as follows, for example.
Output: 50kV, 250mA,
Incident side solar slit: 5 °,
Divergence vertical slit: 2/3 °,
Divergence vertical limiting slit: 5 mm,
Scattering slit 2/3 °,
Light receiving side solar slit: 5 °,
Light receiving slit: 0.3 mm,
BENT monochromator,
Light receiving monochrome slit: 0.8 mm,
Sampling width: 0.01 °,
Scan speed: 4 ° / min,
2θ measurement range: 20-80 °

When obtaining each of the above peak intensities from the chart of the X-ray diffraction pattern obtained by the measurement of the X-ray diffraction method, the analysis software attached to the X-ray diffractometer may be used. When using analysis software, background processing and Kα ₂ peak removal are performed using cubic approximation, and profile fitting is performed using the Pearson-VII function. Thereby, each peak intensity can be obtained.

When the lower layer is formed on the substrate side of the upper layer, each peak intensity may be measured by a thin film X-ray diffraction method so as not to be affected by the lower layer.

Specific examples of the type of coated cutting tool of the present invention include a cutting insert with a replaceable cutting edge for milling or turning, a drill, and an end mill.

Hereinafter, embodiments of the present invention will be specifically described. It should be noted that the following embodiments are embodiments for embodying the present invention, and do not limit the present invention to the scope thereof.

As a base material for Examples (Invention Products 1 to 11) and Comparative Examples (Comparative Products 1 to 6) of the present invention, 93.2% WC-6.5% Co processed into an ISO standard SWMT13T3 shaped insert. A cemented carbide having a composition of −0.3% Cr ₃ C ₂ (or more, by weight%) was prepared.

A metal evaporation source having the composition of each layer shown in Table 1 was placed in the reaction vessel of the arc ion plating apparatus. The prepared base material was fixed to the fixing bracket of the rotary table in the reaction vessel.

Then, the pressure in the reaction vessel was evacuated to 5.0 × 10 ^-3 Pa or less. After evacuation, the substrate was heated to a temperature of 500 ° C. with a heater in the reaction vessel. After heating, Ar gas was introduced into the reaction vessel so that the pressure in the reaction vessel became 5.0 Pa.

A bias voltage of −1000 V was applied to the substrate in an Ar gas atmosphere with a pressure of 5.0 Pa. A current of 10 A was passed through the tungsten filament in the reaction vessel. Under such conditions, the surface of the base material was subjected to ion bombardment treatment with Ar gas for 30 minutes. After the ion bombardment treatment was completed, the inside of the reaction vessel was evacuated until the pressure in the reaction vessel became 5.0 × 10 ^-3 Pa or less.

For Inventions 1-10 and Comparative Products 2-4 and 6, a TiAl evaporation source was used to form the lower layer. Specifically, after evacuation, nitrogen gas was introduced into the reaction vessel to create a nitrogen gas atmosphere at a pressure of 3.0 Pa in the reaction vessel. A bias voltage of −40 V was applied to the substrate. By evaporating the metal evaporation source by an arc discharge with an arc current of 150 A, a lower layer having a composition of (Ti _0.33 Al _0.67 ) N was formed by an arc ion plating method. The temperature of the base material when forming the lower layer was set to 500 ° C. Table 1 shows the average thickness of the lower layers of Inventions 1 to 10 and Comparative Products 2 to 4 and 6.

For the invention product 11, a TiAl evaporation source having a composition different from that used in the above-mentioned invention products 1 to 10 and the comparative products 2 to 4 and 6 was used for forming the lower layer. Other than that, the film forming conditions of the lower layer are the same as the film forming conditions of the above-mentioned invention products 1 to 10 and the comparative products 2 to 4 and 6. Specifically, after evacuation, nitrogen gas was introduced into the reaction vessel to create a nitrogen gas atmosphere at a pressure of 3.0 Pa in the reaction vessel. A bias voltage of −40 V was applied to the substrate. By evaporating the metal evaporation source by an arc discharge with an arc current of 150 A, a lower layer having a composition of (Ti _0.65 Al _0.35 ) N was formed by an arc ion plating method. The temperature of the base material when forming the lower layer was set to 500 ° C. Table 1 shows the average thickness of the lower layer of the invention product 11.

For Comparative Product 5, a lower layer was formed using a Ti evaporation source. Specifically, after evacuation, nitrogen gas was introduced into the reaction vessel to create a nitrogen gas atmosphere at a pressure of 3.0 Pa in the reaction vessel. A bias voltage of −40 V was applied to the substrate. By evaporating the metal evaporation source by an arc discharge with an arc current of 150 A, a lower layer having a TiN composition was formed by an arc ion plating method. The temperature of the base material when forming the lower layer was set to 500 ° C. Table 1 shows the average thickness of the lower layer of Comparative Product 5.

The lower layer was not formed for Comparative Product 1.

Next, for the inventions 1 to 11 and the comparative products 2 to 6, after forming the lower layer and for the comparative product 1, after the ion bombardment treatment, the pressure in the reaction vessel was 5.0 × 10 ^-3 Pa. The substrate was evacuated to the following temperature, and the substrate was heated to the temperature at the start of film formation shown in Table 4. Then, nitrogen gas was introduced into the reaction vessel, the pressure in the reaction vessel was set to 3.0 Pa, and the upper layer (AlN layer) was formed by the arc ion plating method under the conditions shown in Table 4.

For the inventions 1 to 11 and the comparative products 1 to 6, an upper layer was formed on the surface of the base material or the lower layer until the thickness was as shown in Table 1. Then, the power of the heater was turned off, and after the sample temperature became 100 ° C. or lower, the sample was taken out from the reaction vessel.

The average thickness of each layer of the obtained sample was determined as follows. That is, three cross sections were observed by SEM in the vicinity of a position of 50 μm from the cutting edge of the surface of the coated cutting tool facing the metal evaporation source toward the center of the surface. The thickness of each layer was measured, and the average value of the measured thickness was calculated. Table 1 shows the thickness of each layer of each sample thus obtained.

The composition of each layer of the obtained sample was determined as follows. That is, the composition was measured using EDS in a cross section at a position of 50 μm from the cutting edge of the surface of the coated cutting tool facing the metal evaporation source toward the center of the surface. Table 1 shows the composition of each sample thus obtained.

The composition ratio of the metal element in the lower layer of Table 1 indicates the ratio of the number of atoms of each metal element to the entire metal element in the metal compound constituting each layer.

The upper layer of the obtained sample was measured by the X-ray diffraction method of the 2θ / θ concentrated optical system using Cu—Kα rays. The measurement conditions are as follows.
Output: 50kV, 250mA,
Incident side solar slit: 5 °,
Divergence vertical slit: 2/3 °,
Divergence vertical limiting slit: 5 mm,
Scattering slit 2/3 °,
Light receiving side solar slit: 5 °,
Light receiving slit: 0.3 mm,
BENT monochromator,
Light receiving monochrome slit: 0.8 mm,
Sampling width: 0.01 °,
Scan speed: 4 ° / min,
2θ measurement range: 30 to 70 °

From the chart of the X-ray diffraction pattern of the upper layer obtained by the measurement of the X-ray diffraction method, the peak intensity I _h (100) on the hexagonal (100) plane and the diffraction peak intensity I _h (002) on the hexagonal (002) plane. ) And the diffraction peak intensity _Ic (111) of the cubic (111) plane were determined. From these measured diffraction peak intensities, the ratio [I _h (002) / I _h (100)] and the ratio [I _h (002) / I _h (100)] of the diffraction peak intensities were obtained. The results are shown in Table 2.

Using the obtained sample, the following cutting test 1 and cutting test 2 were performed to evaluate the fracture resistance and wear resistance. The evaluation results are shown in Table 5.

The measurement conditions of the cutting test (fracture resistance and wear resistance test) are as follows.
Work material: FCD600,
Work material shape: 200 mm x 100 mm x 60 mm block,
Cutting speed: 200m / min,
Feed: 0.2 mm / t,
Notch: 2.0 mm,
Coolant: Yes,
Evaluation item: When the sample was defective, or when the flank wear width or boundary wear width of the sample reached 0.3 mm, the tool life was defined, and the machining time until the tool life was reached was measured. Table 3 shows the processing time obtained by the measurement. Further, in the "damage form" column of Table 3, "normal wear" is described when there is no defect, and "defect" is described when there is a defect.

As shown in Table 3, in the fracture resistance and wear resistance tests of Inventions 1 to 11, the machining time until the tool life was reached was 62 minutes (Invention 10) or more, which was a good result. On the other hand, the machining time until the tool life of the comparative products 1 to 6 was 47 minutes (comparative product 6) or less, which was not a good result. In Comparative Product 4, a defect was observed in 36 minutes before the flank wear width or the boundary wear width of the sample reached 0.3 mm. Therefore, it can be said that the coated cutting tool of the present invention is a coated cutting tool having excellent wear resistance.

Further, during the above-mentioned fracture resistance and wear resistance tests, problems due to welding resistance such as the test pieces of Inventions 1 to 11 being welded to the work material did not occur. Therefore, it can be said that the coated cutting tool of the present invention is a coated cutting tool having excellent welding resistance.

The coated cutting tool of the present invention is excellent in wear resistance and welding resistance. According to the present invention, the tool life can be extended as compared with the conventional case. Therefore, the industrial applicability of the present invention is high.

1 Base material 2 Lower layer 3 Upper layer 4 Coating layer 5 Coating cutting tool

Claims (4)

A coating cutting tool comprising a substrate and a coating layer formed on the substrate.
The covering layer includes a lower layer and an upper layer formed on the lower layer.
The lower layer has an average thickness of 0.2 μm or more and 5.0 μm or less, and the following formula (1):
(Ti _1-x Al _x ) N (1)
(In the formula, x indicates the atomic ratio of the Al element to the total of the Ti element and the Al element, and satisfies 0.3 ≦ x ≦ 0.7.)
Consists of a composite compound layer having a composition represented by
The upper layer is composed of an AlN layer having an average thickness of 1.5 μm or more and 6.0 μm or less.
The ratio of the diffraction peak intensity I _h (002) of the hexagonal (002) plane to the diffraction peak intensity I _h (100) of the hexagonal (100) plane by the X-ray diffraction method of the upper layer [I _h (002) / I _h (100)] is 5.0 or more ,
The ratio of the diffraction peak intensity I _c (111) of the cubic (111) plane to the diffraction peak intensity I _h (100) of the hexagonal (100) plane by the X-ray diffraction method of the upper layer [I _c (111) / I _h (100)] is 0.5 or more and 5.0 or less, a coated cutting tool. The coated cutting tool according to claim 1, wherein the average particle size of the particles constituting the upper layer is 0.1 μm or more and 1.0 μm or less. The coating cutting tool according to claim 1 or 2 , wherein the average thickness of the entire coating layer is 2.0 μm or more and 7.0 μm or less. The coated cutting tool according to any one of claims 1 to 3 , wherein the substrate is any one selected from cemented carbide, cermet, ceramics and a cubic boron nitride sintered body.

Images