JP2012192513A - Surface coated cutting tool excellent in peel resistance and wear resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface coated cutting tool the hard coated layer of which exhibits peel resistance and chipping resistance in a wet cutting process of a hard difficult-to-cut material such as a Ti based alloy.SOLUTION: In the cutting tool, an oxynitride layer of Ti and Al having an average layer thickness of 0.5 to 3.4 μm is coated on the outermost surface of a tool base, and a nitride layer of Ti and Al having an average layer thickness of 0.8 to 4.0 μm is coated on the lower layer. The oxynitride layer has a porous form having minute pores distributed with a meandering path from the surface toward the depth direction and when it is assumed that the diameter of a circle inscribed in a minute pore when the oxynitride layer is observed from the surface is the pore diameter of the minute pore, the pore diameter of the minute power is 0.1 to 1.5 μm, the specific surface area of the oxynitride layer is 0.4 to 1.0 m/g and the area ratio of the minute pore opening to the area on a substrate when the oxynitride layer is observed from the surface is 0.05 to 0.3.

Description

  Since the present invention includes a porous oxynitride layer having heat dissipation and excellent lubricity on the surface of the hard coating layer under wet cutting conditions, particularly hard materials that generate high heat such as various Ni-based alloys and Ti-based alloys. Even when cutting difficult-to-cut materials, a surface that is hard to generate high heat, suppresses the peeling of the hard coating layer due to the occurrence of welding, and exhibits excellent peeling resistance and chipping resistance over a long period of time The present invention relates to a coated cutting tool (hereinafter referred to as a coated tool).

  In general, for coated tools, throwaway inserts that are detachably attached to the tip of the cutting tool for turning and planing of various steel and cast iron materials, drilling of the work material, etc. Drills and miniature drills, and solid type end mills used for chamfering, grooving and shouldering of the work material, etc. A slow-away end mill tool that performs cutting work in the same manner as an end mill is known.

  Further, on the surface of the tool base made of high-speed tool steel, cemented carbide or cermet, the film thickness of the uppermost layer is in the range of 0.1 to 1.5 μm, and the width is 0.1 to 10.0 μm. A cutting tool having a coating layer having a level of pores is known.

Further, in the conventional coated tool, after TiN or TiAlN is formed by an arc ion plating method, the uppermost layer is formed by a thickness of 0.1 to 1.5 μm, and Ar is added to the reaction gas N _2. The Ti metal, which is a molten particle popping out from the droplet formed on the surface of the uppermost layer, is applied to an abrasive containing ultrafine alumina powder or zirconia fine powder with a pressure (0.5-2) against the arc ion plating surface. ) Perform a blasting process (abrasion process) that blows weakly at about 10 ⁵ Pa, or an aero lap that blasts the surface of the arc ion plating with ultrafine diamond abrasive grains. Manufactured by forming a coating film having a pore with a level of about 0.1 to 10.0 μm and a depth of 0.1 to 1.5 μm on the surface. It is also known to be.

JP 2005-153072 A

  The performance and automation of cutting machines in recent years have been remarkable. On the other hand, there are strong demands for labor saving and energy saving and further cost reduction for cutting. Accordingly, cutting speed has been increased and types of work materials have been increased. There is a tendency that a general-purpose coated tool that is not limited to the above is strongly desired. However, in the conventional coated tool, when a hard difficult-to-cut material such as an Al-Si alloy is cut, a long life is obtained. Although shown, this occurs during cutting when high-speed cutting of hard difficult-to-cut materials such as various Ni-based alloys and Ti-based alloys, where heat conductivity is low and heat tends to stay at the tool edge during cutting. As a result, welding to the tool edge is likely to occur due to extremely high heat generation, and due to this, the hard coating layer is peeled off and chipped, so that the service life is reached in a relatively short time.

  In view of the above, the present inventors have earnestly developed a coated tool that exhibits excellent peeling resistance and chipping resistance with a hard coating layer in high-speed cutting of the hard difficult-to-cut materials. As a result of the research, the following findings were obtained.

  First, in the conventional coated tool (Patent Document 1), a TiN layer or a TiAlN layer is formed by an arc ion plating method, and this is used for cutting hard difficult-to-cut materials such as Al-Si alloys. However, when this is used for high-speed cutting of hard difficult-to-cut materials such as various Ni-based alloys and Ti-based alloys, the retention effect of the cutting oil is not sufficient. It was ascertained that welding was caused by extremely high heat generation caused by the phenomenon, and that the hard coating layer was peeled off due to the welding.

  Therefore, the present inventors conducted research with a focus on the TiAlNO layer structure that hardly causes the occurrence of welding and has a high cutting oil retention effect. As shown in Patent Document 1, the TiAlN layer is formed. The film is not simply formed by the arc ion plating method, but a hard coating of TiAlN is formed by the arc ion plating method, and then an oxygen plasma treatment is performed under specific conditions using an assist gun to form a hard coating layer. By forming a thin oxide film that is an insulator that easily stores positive charges on the surface, and causing dielectric breakdown due to arc discharge mediated by oxygen anions or electrons in the plasma formed around the substrate and its surroundings, A TiAlNO layer having micropores distributed along a meandering path can be formed on the surface layer, and the hard coating layer thus obtained can be used for various Ni Even in high-speed cutting of hard difficult-to-cut materials such as alloys and Ti-based alloys, a TiAlNO layer that hardly generates heat and does not easily weld due to the porous surface structure and the high cutting oil retention effect due to the fine hole shape It was found that a film can be formed.

Specifically, FIG. 1 shows a schematic plan view of an arc ion plating apparatus. A cathode electrode (evaporation source) made of a Ti—Al alloy is arranged in the arc ion plating apparatus, and the atmosphere in the apparatus is changed. In an Ar atmosphere, arc discharge is performed, N ₂ is introduced as a reaction gas to form a hard film, and an oxygen plasma is generated using an assist gun with a discharge voltage of 130 V, a filament current of 36 A, a coil current of 16 A, and a bias voltage of 100 V. When the treatment is performed, it is possible to form an oxynitride layer having a porous shape that has a high cutting oil retention effect in wet cutting and greatly improves heat dissipation efficiency, so that it is difficult to cause welding due to high heat generated during cutting. And peeling of the film by welding can be suppressed.

  As a result, the coated tool of this result has excellent oil retention and heat dissipation of the cutting fluid that is excellent in the upper layer in wet high-speed cutting of hard difficult-to-cut materials such as various Ni-based alloys and Ti-based alloys with particularly high heat generation In addition, since the oxynitride layer having welding resistance and the nitride layer having excellent wear resistance corresponding to the untreated portion of the oxygen plasma are compatible with each other, particularly, the hard coating layer is peeled off due to welding. It has been found that by suppressing the above, excellent peeling resistance and wear resistance can be exhibited over a long period of time.

The present invention has been made based on the above findings,
“(Ti _1−X Al _X ) (N _1−Y O _Y ) (wherein the atomic ratio, X is 0.40 to 0.40) on the outermost surface of the tool base made of tungsten carbide based cemented carbide or titanium carbonitride based cermet 0.75 and Y represents 0.1 to 0.4), and an Ti and Al oxynitride layer having an average layer thickness of 0.5 to 3.4 μm, and (Ti _1-X Al _X ) N (wherein X is 0.40 to 0.75 in atomic ratio) and Ti and Al nitride having an average layer thickness of 0.8 to 4.0 μm A cutting tool coated with a layer,
The oxynitride layer has a porous shape having micropores distributed in a depth direction from the surface, and has a diameter of a circle inscribed in the micropores when the oxynitride layer is observed from the surface. In the case of the fine pore diameter, the fine pore diameter is 0.1 to 1.5 μm,
The specific surface area of the oxynitride layer is 0.4 to 1.0 m ² / g,
The surface-coated cutting tool, wherein an area ratio of the micropore opening to an area on the base material when the oxynitride layer is observed from the surface is 0.05 to 0.3. ”.

Next, the coated tool of the present invention will be described in detail.
Composition of Ti and Al oxynitride layer having outermost porous shape:
When the average oxygen content ratio Y (however, the atomic ratio) in the total amount of nitrogen and oxygen of the surface oxynitride layer having a porous shape is 0.1 or less, the lubricity formed during cutting is improved. If the oxide is not formed sufficiently, if it is 0.4 or more, a large amount of oxide is formed and the structure becomes brittle, or the lattice strain of the structure increases due to the solid solution of a large amount of oxygen, and the structure becomes fragile. Therefore, the average oxygen content ratio Y of the oxynitride layer was determined to be 0.1 to 0.4.

Further, when the Al content ratio X (however, the atomic ratio) in the total amount of Ti and Al is less than 0.40, high hardness and oxidation due to lattice distortion caused by Al substitution to Ti sites in the TiN lattice. Since the oxidation resistance by the protective film is not obtained, a hexagonal structure oxynitride that does not have sufficient hardness is formed if it is 0.75 or more, and the desired high-temperature toughness and high-temperature strength cannot be obtained. The Al content ratio X was set to 0.40 to 0.75.
Average layer thickness of Ti and Al oxynitride layers having the outermost porous shape:
The TiAlNO layer formed on the outermost surface of the tool base made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet, when the average layer thickness is less than 0.5 μm, a sufficient cutting oil retaining effect cannot be obtained, If the average layer thickness exceeds 3.4 μm, peeling due to welding can be suppressed in high-speed cutting of hard difficult-to-cut materials such as Ni-based alloys and Ti-based alloys, but chipping of the cutting edge portion is likely to occur. Therefore, the average layer thickness was determined to be 0.5 to 3.4 μm.
The composition of the lower nitride layer:
When the Al content ratio X (however, the atomic ratio) in the total amount of Ti and Al of the Ti and Al nitride layer constituting the lower layer is less than 0.40, Al substitution to Ti sites in the TiN lattice The hexagonal structure nitride which does not have sufficient hardness due to the high hardness resulting from the lattice strain imparted by the material and the oxidation resistance due to the dense oxidation protective film formed during cutting, and does not have sufficient hardness when it is 0.75 or more Since the desired high-temperature toughness and high-temperature strength were not obtained, the Al content ratio X was determined to be 0.40 to 0.75.
Average layer thickness of nitride layer:
When the average layer thickness of the nitride layer corresponding to the plasma unprocessed portion is less than 0.8 μm, the wear resistance of the nitride layer cannot be exhibited, while the average layer thickness is 4.0 μm. If it exceeds, chipping of the cutting edge portion is likely to occur, so the average layer thickness was set to 0.8 to 4.0 μm.
Micropore shape and hole diameter:
The micropores of the oxynitride layer are not spherical micropores but have a shape having a meandering path in the depth direction from the surface of the oxynitride layer. When the diameter of the circle inscribed in the micropores when the oxynitride layer is observed from the surface is the pore size of the micropores, if the average pore size is less than 0.1 μm, it is difficult to hold a sufficient amount of cutting fluid. On the other hand, if the average pore diameter exceeds 1.5 μm, the retention effect of the cutting fluid due to capillary action is reduced, and the structure breaks without being able to withstand the load during cutting. .5 μm.
Specific surface area:
When the specific surface area, that is, the area per unit weight is 0.4 m ² / g or less, there is not enough surface area to provide a capillary force for holding a sufficient cutting fluid, so that welding due to high heat generation is likely to occur and peeling. Resulting in. In addition, those satisfying 1.0 m ² / g or more have a very small pore diameter and a large number of micropores, and the oxynitride layer having poor wear resistance results in destruction of the structure. End up. Moreover, since the oil agent holding | maintenance amount will decrease, the specific surface area of the oxynitride layer was determined to be 0.4-1.0 m < ² > / g. Here, the specific surface area is assumed to be the same as the weight of the hard coating layer before the plasma treatment in which the weight of the oxynitride layer in the unit area on the base material is deformed by the oxygen plasma treatment, and an atomic force microscope. Is the value obtained by dividing the surface area measured by the above-mentioned assumed weight.

  Furthermore, conventional fine pores close to a sphere as disclosed in the prior art cannot achieve both weight and surface area, and cannot provide the cutting oil retaining effect due to the capillary phenomenon unique to the present invention.

  That is, in the past, micropores were created by mechanical and scientific removal of droplets or by depositing and dissolving carbon compounds inside the hard coating, but these methods are spherical and nearly spherical. Only holes with a shape can be made. However, according to the present invention, since elongated fine holes distributed while bending in the depth direction can be produced, the high retention effect of the cutting fluid due to the large surface area and small hole diameter, The effect of extending the cutting life can be expected from the fine holes.

  Generally, it is known that the height of the liquid level when a liquid is held in a cylindrical tube by capillarity becomes higher as the inner diameter of the tube is smaller. Therefore, the smaller the inner diameter is, the higher the amount of holding the cutting fluid is. . However, if only spherical and sphere-like holes can be produced, the inner diameter and volume of the spherical holes are in a simple increase relationship, so that it is impossible to achieve both a sufficient force for holding the cutting fluid and a sufficient amount for holding.

That is, in the prior art, the effect of the capillary action for retaining the cutting fluid is low, and the cutting fluid cannot be sufficiently retained.
Area ratio of the micropore opening to the area on the substrate when the oxynitride layer is observed from the surface:
If the area ratio of the fine hole openings is small, the retention effect of the cutting fluid is reduced. On the other hand, if the size is large, the structure cannot withstand the load during cutting and breaks. Therefore, the area ratio of the micropore opening to the area on the base material when the oxynitride layer is observed from the surface is determined to be 0.05 to 0.3.

  Next, a method for manufacturing the coated tool of the present invention will be described.

The hard coating layer as described above is, for example, charged in an arc ion plating (AIP) apparatus, which is one type of physical vapor deposition apparatus schematically shown in FIG. A cathode electrode (evaporation source) made of a Ti—Al alloy having a predetermined composition is placed in the apparatus while being heated to a temperature of 500 ° C., and, for example, a current flows between the anode electrode and the cathode electrode (evaporation source). : An arc discharge was generated under the condition of 90 A, and simultaneously nitrogen gas was introduced into the apparatus as a reaction gas to obtain a reaction atmosphere of, for example, 2 Pa. On the other hand, a bias voltage of, for example, −100 V was applied to the substrate. A hard film made of TiAlN is formed by vapor deposition under conditions. Thereafter, using an assist plasma gun, for example, a discharge voltage of 130 V, a filament current of 36 A, a coil current of 16 A, an Ar introduction gas of 15 ml / min. , O ₂ introduced gas 30 ml / min. Then, oxygen plasma treatment is performed at a bias voltage of 100 V to form a thin oxide film that is an insulator that easily stores positive charges on the surface of the hard coating layer, and oxygen anions or electrons in the plasma formed around the substrate and its periphery. By causing dielectric breakdown caused by arc discharge mediated by oxynitride, the upper layer is formed from an oxynitride layer having fine holes distributed with meandering paths, and the lower layer is formed from a nitride layer corresponding to an oxygen plasma untreated portion. The hard coating layer which becomes can be produced. At this time, if the discharge voltage, filament current, and bias are large, the arc discharge becomes strong, the fine holes are deep, and the hole diameter is also large.

  In the coated tool of the present invention, the hard coating layer is subjected to plasma treatment in an oxygen atmosphere, so that the surface of the coating is modified to an oxynitride layer having micropores. Since the oil penetrates and the heat radiation efficiency to the cutting oil is greatly improved, welding due to extremely high heat generated during cutting hardly occurs, and peeling of the film due to welding can be suppressed. Also, by adding oxygen to the surface layer, it promotes the formation of oxides with a low coefficient of friction during cutting, improves the evacuation of chips and the like that enter the fine holes, and wear resistance of the oxynitride layer As a result, the porous shape is maintained over a long period of time, and the oxynitride layer and the nitride layer can be compatible with each other in a well-balanced manner, so that high heat is generated in wet cutting conditions that generate high heat such as Ti alloys. As a result, the welding peeling is suppressed, and the effect of extending the life is exhibited.

It is a schematic plan view of the arc ion plating (AIP) apparatus used for forming the hard coating layer of the coated tool of the present invention. A scanning electron micrograph (magnification: 1000 times) of the surface texture of the oxynitride layer of the coated chip 16 of the present invention is shown.

  Next, the coated tool and the manufacturing method thereof according to the present invention will be specifically described with reference to examples.

As raw material powders, WC powder, TiC powder, ZrC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder and Co powder each having an average particle diameter of 1 to 3 μm are prepared. , Blended in the composition shown in Table 1, wet-mixed for 72 hours in a ball mill, dried, and then pressed into a green compact at a pressure of 100 MPa, and the green compact was vacuumed at 6 Pa, temperature: 1400 ° C. WC-based cemented carbide tool with ISO standard and CNMG120408 throwaway tip shape after sintering under the condition of holding for 1 hour, and then performing honing of R: 0.03 on the cutting edge part after sintering Bases A-1 to A-8 were formed.

In addition, as raw material powders, all of TiCN (weight ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder having an average particle diameter of 0.5 to 2 μm Co powder and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and then pressed into a compact at a pressure of 100 MPa. The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to obtain ISO standard / CNMG120408. The tool bases B-1 to B-6 made of TiCN base cermet having the shape of the throwaway tip were formed.
(A) Next, each of the tool bases A-1 to A-8 and B-1 to B-6 is ultrasonically cleaned in acetone and dried, and then the arc ion plating apparatus shown in FIG. It is mounted along the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the inner rotary table, and is used for forming a hard coating layer as a cathode electrode (evaporation source) on opposite sides across the rotary table. Ti-Al alloy is placed,
(B) First, the inside of the apparatus is heated to 500 ° C. with a heater while the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, and then the tool base that rotates while rotating on the rotary table is −1000 V. A DC bias voltage is applied and a current of 100 A is passed between the cathode electrode and the anode electrode to generate an arc discharge, thereby bombarding the tool substrate surface,
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 4 Pa, a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table, and A current of 120 A is passed between the Ti—Al alloy of the cathode electrode and the anode electrode to generate an arc discharge, and a (Ti, Al) N layer is deposited on the surface of the tool base, and then the cathode electrode (evaporation source) ) And the anode discharge between the anode electrode and
(D) Next, using an assist gun in the apparatus, a discharge voltage of 130 V, a filament current of 36 A, a coil current of 16 A, an Ar introduction gas of 15 ml / min. , O ₂ introduced gas 30 ml / min. By performing the oxygen plasma treatment at a bias voltage of 100 V, the hard coating layer is formed from the oxynitride layer having the porous layer shape having the predetermined layer thickness and the average oxygen content with the target layer thickness shown in Table 3 Formed on the surface of
The present invention coated tools 1 to 18 (hereinafter referred to as the present invention chips 1 to 18) each having a throwaway tip shape defined in ISO / CNMG120408 were manufactured.

For the purpose of comparison, each of the tool bases A-1 to A-8 and B-1 to B-6 is bombarded by the same method as the present invention,
Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 4 Pa, a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table, and the cathode electrode A current of 120 A is passed between the Ti-Al alloy and the anode electrode to generate an arc discharge, and a TiAlN layer as a single layer having a target composition and target layer thickness shown in Table 4 is deposited on the surface of the tool base. After forming, forming a TiAlN layer formed by adding Ar gas to nitrogen gas to form Ti metal droplets, and removing Ti metal by blasting,
Comparative example coated tools 1 to 14 (hereinafter, referred to as comparative example chips 1 to 14) having a throwaway tip shape defined in ISO · CNMG120408 were manufactured, respectively.

  For reference, the same apparatus as the apparatus for manufacturing the coated chips 1 to 18 of the present invention shown in FIG. 1 is used, and the film is formed with a composition, film thickness, and assist plasma gun conditions different from those of the coated chips 1 to 18 of the present invention. Thus, reference coated tools (hereinafter referred to as reference coated chips) 1 to 4 having a throwaway tip shape defined in ISO · CNMG120408 shown in Table 4 were produced.

  Next, about the hard coating layer of this invention chip | tip 1-18 and the reference coating | coated chips 1-4, the cross-sectional measurement by a scanning electron microscope was performed, and the film thickness of the oxynitride layer and the film thickness of the nitride layer were calculated | required. . Further, the diameter of a circle inscribed in the fine hole when observed from the surface with a scanning electron microscope was obtained as the hole diameter of the fine hole. Further, the surface area of the oxynitride layer in the unit area on the substrate is measured by an atomic force microscope, and the weight of the oxynitride layer in the unit area on the substrate is deformed by oxygen plasma treatment before the hard coating layer before the plasma treatment The specific surface area was determined on the assumption that the weight was the same as the weight of. Further, the oxynitride layer was observed from the surface with a scanning electron microscope, and the area of the micropore opening existing in a unit area on the substrate was determined to obtain an area ratio.

  These measured values are shown in Tables 3 and 4.

Moreover, about the hard coating layer of the comparative example chips | tips 14-14, the cross-sectional measurement by a scanning electron microscope was performed, and the film thickness of the whole hard coating layer and the depth in which a pore is located were calculated | required. Further, the width of the pore was determined when the diameter of the circle inscribed in the pore was taken as the width of the pore by a scanning electron microscope.
These measured values are shown in Table 4.

  Moreover, when the composition of the wear-resistant hard layer constituting the hard coating layer of the present invention chips 1 to 18, comparative example chips 1 to 14 and reference coated chips 1 to 4 was measured by an electron beam microanalyzer (EPMA), respectively. The composition was substantially the same as the target composition.

  Further, when the average layer thickness of the hard coating layer was subjected to cross-sectional measurement using a scanning electron microscope, all of them showed an average value (average value of five locations) substantially the same as the target layer thickness.

Next, in the state where all the above-mentioned various coated chips are screwed to the tip of the tool steel tool with a fixing jig, the present chips 1 to 18, the comparative chips 1 to 14 and the reference coated chips 1 to 1 are used. For 4,
Work material: Ti-6% Al-4% V alloy round bar by mass%,
Cutting speed: 140 m / min. ,
Cutting depth: 1.0 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 5 minutes
Wet high-speed cutting test (normal cutting speed and feed are 120 m / min. And 0.2 mm / rev., Respectively) of Ti-based alloy under the above conditions (referred to as cutting condition A), and the flank face of the cutting blade The wear width was measured.

  The measurement results are shown in Table 5.

表５に示される結果から、優れた耐摩耗性を有する窒化物層に加え、蛇行経路を持って分布する微細孔を有する酸窒化物層がすぐれた切削油剤の保油性と耐溶着性を有する本発明被覆工具は、各種のＮｉ系合金やＴｉ系合金などの硬質難削材の高熱発生を伴う高速切削で、すぐれた耐剥離性と耐摩耗性を発揮する。

From the results shown in Table 5, in addition to the nitride layer having excellent wear resistance, the oxynitride layer having fine pores distributed with meandering paths has excellent oil retention and welding resistance of the cutting fluid. The coated tool of the present invention exhibits excellent peeling resistance and wear resistance in high-speed cutting accompanied by high heat generation of hard difficult-to-cut materials such as various Ni-based alloys and Ti-based alloys.

  On the other hand, in the conventional coated tool, as shown in Table 5, since the fine holes constituting the oxynitride layer are not distributed with meandering paths, the oil retaining property of the cutting fluid is inferior, and hard difficult-to-cut materials The peeling of the hard coating layer cannot be suppressed under high-speed cutting conditions accompanied by the generation of high heat, and the wear resistance is poor.

  In the above embodiment, the performance of the hard coating layer was evaluated using a throwaway tip, but it goes without saying that the same result can be obtained with a drill, a miniature drill, an end mill, or the like.

  As described above, according to the coated tool and the manufacturing method thereof of the present invention, not only cutting under normal cutting conditions such as various steels and cast irons, but also high speeds of the hard difficult-to-cut materials with particularly high heat generation. Since it exhibits excellent peeling resistance and wear resistance even in cutting processing, and exhibits excellent cutting performance over a long period of time, higher performance and automation of cutting equipment, and labor saving and energy saving of cutting processing In addition, it can cope with the cost reduction sufficiently satisfactorily.

Claims (1)

(Ti _1-X Al _X ) (N _1-Y O _Y ) (wherein atomic ratio, X is 0.40 to 0) on the outermost surface of the tool base made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet .75 and Y represents 0.1 to 0.4), and an Ti and Al oxynitride layer having an average layer thickness of 0.5 to 3.4 μm, and (Ti _{1 -X} Al _X ) N (wherein X is 0.40 to 0.75 in atomic ratio), and a Ti and Al nitride layer having an average layer thickness of 0.8 to 4.0 μm A cutting tool coated with
The oxynitride layer has a porous shape having micropores distributed in a depth direction from the surface, and has a diameter of a circle inscribed in the micropores when the oxynitride layer is observed from the surface. In the case of the fine pore diameter, the fine pore diameter is 0.1 to 1.5 μm,
The specific surface area of the oxynitride layer is 0.4 to 1.0 m ² / g,
The surface-coated cutting tool, wherein an area ratio of the micropore opening to an area on the base material when the oxynitride layer is observed from the surface is 0.05 to 0.3.

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