JP2006181706A - Surface coated cutting tool and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cutting tool and a manufacturing method thereof, lowering the temperature of the knife edge of a tool in high-speed dry machining and achieving a long life by imparting a lubricating function to a coating film. <P>SOLUTION: This surface coated cutting tool includes a base material, and the coating film laminated on the surface of the base material, wherein the coating film is composed of an A layer, a B layer and a C layer, and the B layer and the C layer are alternately stacked on the A layer, wherein the A layer is made of a nitride of Ti<SB>a</SB>Si<SB>b</SB>(wherein 0<b<0.3, a+b=1) formed directly on the base material, the B layer is made of nitride, carbonitride, nitroxide or carbonitride of Al<SB>c</SB>Ti<SB>d</SB>M<SB>e</SB>(wherein 0.4<c<0.75, 0<e<0.3, c+d+e=1 )(M is one or more kinds of elements selected from a group of Si, Cr, V, Y, Zr, B, Zn, Mo and Mn), and the C layer is made of carbonitride of Ti<SB>f</SB>Si<SB>g</SB>(wherein 0<g<0.3, f+g=1). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cutting tool such as a drill, an end mill, a milling or turning cutting edge replaceable tip, a metal saw, a cutting tool, a reamer, or a tap, and more particularly, a cutting in which a coating layer having wear resistance is formed on the surface thereof. The present invention relates to a tool and a manufacturing method thereof.

  Recent cutting tool trends include the need for dry machining without cutting fluids from the viewpoint of global environmental conservation, the diversification of work materials, and higher cutting speeds to further improve machining efficiency. For example, the tool edge temperature tends to become higher. As a result, the tool life is shortened, and the properties required for the tool material are becoming stricter.

  In particular, the required properties of the tool material include not only the stability of the coating film at high temperatures (oxidation resistance and adhesion of the coating film), but also the wear resistance related to the cutting tool life, ie the coating film Improvements in hardness at high temperatures and lubrication properties of coating films that replace lubricants are becoming increasingly important.

  Here, the structure of the cutting edge of a general cutting tool will be described. FIG. 1 shows a schematic cross-sectional view of a typical cutting edge of a cutting tool. In FIG. 1, a tool 1 includes a base material 2 and a coating layer 3 formed on the surface of the base material 2. The cutting edge is constituted by the rake face 4 of the tool and the flank face 5 of the tool. In many cases, the angle formed by the rake face 4 and the flank face 5 is an acute angle or a right angle. When the coating layer is formed on such a tool blade edge, the film thickness of the coating edge layer 8 becomes the largest compared to the rake face film thickness 6 and the flank face film thickness 7 as shown in the figure.

  Furthermore, the ideal wear progress at the tool edge will be described with reference to FIGS. The ideal wear as a tool is that the coating layer gradually wears away from the acute angle or right-angled portion indicated by the film thickness 8 as shown in FIG. 2 (a), and eventually the substrate as shown in FIG. 2 (b). After reaching the above, finally, as shown in FIG. 2C, the coating layer and the base material are both exposed and worn.

  However, as a result of detailed investigations of the tool wear part by the inventors, the wear at the tip of the cutting edge does not proceed as shown in FIG. 2 described above, and the edge of the cutting edge is already at line X as shown in FIG. It was found that the base material was lost due to the chipping shown, and the portion 10 of the base material was completely exposed and lost from its form. In addition, the base material 11 of the defective portion has already been oxidized, and no matter how good the oxidation resistance and wear resistance of the film, if the base material is exposed at the initial stage of cutting, the tool life is remarkably improved. It seems difficult.

  Therefore, in cutting tools under severe conditions such as high speed machining and dry machining, not only the oxidation resistance of the coating film is improved, but also the chipping or chipping of the cutting edge that occurs at the beginning of cutting, that is, the exposure of the substrate It is very important how to suppress this.

  On the other hand, in Non-Patent Document 1 below, the surface of a hard base material such as a cutting tool such as a WC-based cemented carbide, cermet, and high-speed steel, or a wear-resistant tool is used to improve wear resistance and surface protection function. In addition, it is disclosed that a single layer or a plurality of layers of TiAl nitride are formed as a hard coating layer.

  However, in recent high-speed machining and dry machining, the cutting edge temperature of the tool reaches 900 ° C. or higher, and therefore, a sufficient tool life cannot be obtained with the TiAlN coating.

  Further, Patent Document 1 and Patent Document 2 listed below describe nitrides, carbonitrides, nitride oxides or carbonitride oxides containing Ti as a main component and containing Ti in an appropriate amount for improving heat resistance, and Ti and It is disclosed that a nitride, carbonitride, nitrided oxide, or carbonitride multilayer coating containing Al as a main component is applied to a cutting tool. The TiSi-based film has a dense oxidation protective film containing Si formed on the outermost surface, and has better heat resistance than the TiAl-based film.

  However, since the TiSi-based coating itself is highly brittle, there has been a problem that the entire coating is broken or peeled off by an impact during cutting. In the invention described in the patent document, in order to improve the adhesion between the base material and the film, a film mainly composed of TiN or TiAl is formed immediately above the base material. When the coating composed of TiN or TiAl as a main component is exposed on the surface, the progress of the oxidation is accelerated and the interior of the substrate is oxidized to reach the tool life, which is a problem.

Furthermore, in Patent Document 3 below, TiSi nitride is arranged directly on the substrate, but under the film formation conditions disclosed in Document 3, the compressive stress in the film is very high, and the pressure with the substrate The problem is that the adhesion strength of the coating due to the difference is extremely lowered.
Japanese Patent No. 3347687 Japanese Patent No. 3248897 Japanese Patent No. 3480086 Kobe Steel Engineering Reports Vo. 41 no. 3 (1991) page 10

  The present invention has been made in order to solve the above-mentioned problems of the prior art, and its purpose is to form a TiSi-based film having a higher adhesion directly on the base material and to form a laminate of the film with a specific structure. To provide a lubricating function to the coating film, thereby reducing the temperature of the tool edge during high-speed and dry machining, and at the same time, achieving a longer service life and its manufacture It is to provide a method.

According to one aspect of the present invention, there is provided a surface-coated cutting tool including a base material and a coating film laminated on the surface of the base material, wherein the coating film is formed directly on the base material. Ti _a Si _b (However, 0 <b <0.3, a + b = 1) and a layer made of a nitride _of, Al c _Ti d _{M e} (however, 0.4 <c <0.75,0 <e <0.3, c + d + e = 1) (M is one or more elements selected from the group consisting of Si, Cr, V, Y, Zr, B, Zn, Mo and Mn), nitride, carbonitride, nitrogen B layer made of oxide or carbonitride and C layer made of carbonitride of Ti _f Si _g (where 0 <g <0.3, f + g = 1). The layers are alternately stacked, and at least one of the B layer and the C layer is stacked, and the other is at least two layers. Surface-coated cutting tool, characterized in that it is the upper stacked is provided.

  Preferably, the coating layer has a total film thickness in the range of 0.5 μm to 10 μm.

  Preferably, the coating layer has a thickness of the A layer in the range of 0.05 μm to 1.0 μm.

  Preferably, in the coating layer, the thicknesses of the B layer and the C layer are each independently in the range of 0.05 μm or more and 6 μm or less.

  Preferably, the uppermost layer of the coating layer is a B layer.

  Preferably, the uppermost layer of the coating layer is a C layer.

  Preferably, the base material is selected from the group consisting of WC-based cemented carbide, cermet, high speed steel, ceramics, cubic boron nitride sintered body, diamond sintered body, silicon nitride sintered body, aluminum oxide and titanium carbide. A base material using one or more selected materials.

According to another aspect of the present invention, a substrate, a manufacturing method of the surface-coated cutting tool and a coating film which is laminated on the surface of the substrate, directly on the substrate, Ti _a Si _b (where, 0 <b <0.3, a + b = 1) forming a layer a consisting of a nitride _of, Al c _Ti d _{M e} (however, 0.4 <c <0.75,0 <e <0.3, c + d + e = 1) (M is one or more elements selected from the group consisting of Si, Cr, V, Y, Zr, B, Zn, Mo and Mn), nitride, carbonitride, nitrogen A step of alternately stacking B layers made of oxide or carbonitride and C layers made of carbonitride of Ti _f Si _g (where 0 <g <0.3, f + g = 1). A method for manufacturing a surface-coated cutting tool is provided.

  Preferably, the step of alternately laminating includes the step of laminating and forming B layers on the A layer.

  Preferably, the step of alternately laminating includes the step of laminating and forming the C layer on the A layer.

  Preferably, in the step of alternately laminating, one or more of each of the B layer and the C layer is formed.

  Preferably, the step of alternately laminating includes the step of laminating so that the uppermost layer of the coating layer is the B layer.

  Preferably, the step of alternately laminating includes the step of laminating and forming the C layer as the uppermost layer of the coating layer.

  Preferably, the step of laminating and forming the A layer is performed using a physical vapor deposition method, in which the bias power source is in the range of 0 to 30 V and the pressure of the nitrogen gas is in the range of 3 to 6 Pa. The substrate temperature is set to 450 ° C. or higher.

  Preferably, the step of alternately stacking layers uses a physical vapor deposition method when stacking the C layers, and the bias voltage is set to 200 V or higher.

  According to the surface-coated cutting tool of the present invention, it is possible to improve wear resistance, oxidation resistance, and heat resistance by imparting a specific structure to the coating film, thereby improving the life of the cutting tool. Can do.

The present invention will be described with reference to FIG. As shown in FIG. 4, the surface-coated cutting tool 1 of the present invention includes a base material 2 and a coating film that is laminated on the surface of the base material. The coating film includes an A layer 12 made of a nitride of Ti _a Si _b (where 0 <b <0.3, a + b = 1) formed directly on the substrate, and Al _c Ti _{d Me} (where 0.4 <c <0.75, 0 <e <0.3, c + d + e = 1) (M is an element selected from the group consisting of Si, Cr, V, Y, Zr, B, Zn, Mo and Mn A layer B made of nitride, carbonitride, nitride oxide or carbonitride, and Ti _f Si _g (where 0 <g <0.3, f + g = 1). The B layer and the C layer are alternating layers 13 alternately stacked on the A layer, and at least one of the B layer and the C layer is stacked, and the other is At least two or more layers are laminated.

  FIG. 5 is a schematic cross-sectional view taken along line VV in FIG. As can be seen from FIG. 5, in the surface-coated cutting tool 1 of the present invention, B layers and C layers are alternately laminated in alternating layers 13. Here, the number of layers in the alternating layers 13 shown in FIG. 5 is an example, and is not intended to be limited to this.

As described above, the surface-coated cutting tool 1 of the present invention provides adhesion between the base material 2 and the A layer 12 made of nitride of Ti _a Si _b (where 0 <b <0.3, a + b = 1). than conventionally is strengthened further, on the a _layer, Al c _Ti d _{M e} (however, 0.4 <c <0.75,0 <e <0.3, c + d + e = 1) (M is Si, A layer B made of a nitride, carbonitride, nitride oxide or carbonitride of one or more elements selected from the group consisting of Cr, V, Y, Zr, B, Zn, Mo and Mn; and Ti _f By alternately laminating C layers that are carbonitrides of Si _g (where 0 <g <0.3, f + g = 1) to form alternate layers 13, the alternating B layers and C layers alternate. Excellent lubricity can be imparted to the entire layer. As a result, by using such a coating layer configuration, it is possible to achieve excellent wear resistance, oxidation resistance, and heat resistance as a whole coating film, and thus improve the life as a cutting tool. It is.

(Coating layer)
In the surface-coated cutting tool of the present invention, an A layer made of a nitride of Ti _a Si _b (where 0 <b <0.3, a + b = 1) is formed directly on the base material in the coating layer. The A layer is excellent in oxidation resistance, and can protect the base material from oxidation even if the wear of the coating film proceeds.

  In the present invention, the A layer is characterized in that the adhesion to the substrate is greatly improved as compared with a conventional film having the same composition. That is, conventionally, the film is generally formed by a physical vapor deposition method such as an arc ion plating method, but TiSiN has a high compressive residual stress and is easily peeled off due to a large stress difference from the substrate.

  In the physical vapor deposition method, the inventors set the bias voltage applied to the substrate within a range of 0 to 30 V, the nitrogen gas pressure within a range of 3 to 6 Pa, and the substrate temperature of 450. It has been found that by setting the temperature to not less than ° C., the stress of TiSiN is reduced, and thus the adhesion to the substrate is greatly improved.

  The above condition is a value that is difficult to conceive conventionally in the field, that is, in the present invention, the above condition has a very low bias voltage, a very high nitrogen gas pressure, and a substrate temperature as compared with the conventional condition. It is set relatively high.

  That is, in the conventional technical common sense, when the bias voltage is set low as defined in the present invention during film formation, the compressive stress in the coating film is too low, and the strength of the coating film is extremely reduced. If the nitrogen gas pressure is increased, there may be a problem that the exhaust pressure of the vacuum pump is insufficient and the furnace pressure becomes unstable. If the substrate temperature is increased, the compression in the coating film There was a risk that the stress was released and the film strength decreased. In this respect, it can be said that the setting of such conditions in the present invention is far from the range of technical design items that can be easily assumed by those skilled in the art.

  More preferably, the bias voltage applied to the substrate is in the range of 15 to 25 V, the pressure of the nitrogen gas is in the range of 4 to 5 Pa, and the substrate temperature is 500 ° C. or higher.

In the present invention, the A layer has a nitride composition of Ti _a Si _b (where 0 <b <0.3, a + b = 1). By setting the composition of TiSi in the A layer, it is excellent in high hardness and high heat resistance. Moreover, it can be set as the film | membrane excellent in adhesiveness with a base material by making this into nitride.

In the present invention, in the composition of the layer A: Ti _a Si _b (where 0 <b <0.3, a + b = 1), 0 <b <0.3. When Si is 30 atomic% or more, the toughness of the A layer is lowered, which is not preferable. More preferably, 10 <b <25. In addition, a and b show the atomic composition ratio of Ti element and Si element.

  In the present invention, the thickness of the A layer is preferably 0.05 μm or more and 1.0 μm or less. When the thickness is less than 0.05 μm, the effect of heat resistance is reduced, and when it exceeds 1.0 μm, the coating itself has high brittleness and may be broken by an impact during cutting. More preferably, it is 0.1 μm or more and 0.3 μm or less.

  In the present invention, a film in which B layers and C layers are alternately stacked is formed on the A layer. Of these alternating layers, the B layer will be described.

In the present invention, B _layer, Al c _Ti d _{M e} (however, 0.4 <c <0.75,0 <e <0.3, c + d + e = 1) (M is Si, Cr, V, Y, 1 type or more of elements selected from the group consisting of Zr, B, Zn, Mo and Mn) nitride, carbonitride, nitride oxide or carbonitride. By having the composition of AlTi, it is possible to achieve a good balance between wear resistance and toughness. Further, the B layer further includes one or more elements selected from the group consisting of Si, Cr, V, Y, Zr, B, Zn, Mo and Mn as the metal element M, thereby further improving the hardness. To do.

  M in the B layer in the present invention can use Si, Cr, V, Y, Zr, B, Zn, Mo, and Mn elements. These elements are used in AlTi nitride and carbonitride. Since it has a common feature of acting as a solid solution element and distorting the crystal, the effect of improving the hardness can be exhibited by using any element. In particular, Si or Cr is a preferable element from the viewpoint of improving heat resistance.

In B layer in the present _invention, Al c _Ti d _{M e} has a 0.4 <c <0.75,0 <e < 0.3, the composition ratio of c + d + e = 1. When Al is 40 atomic% or less, there is a possibility that a problem that the heat resistance is lowered, and when it exceeds 75 atomic%, there is a possibility that a problem that the strength of the coating film is lowered. More preferably, 45 <c <65. Note that c, d, and e indicate the composition ratio of Al, Ti, and M atoms.

  Further, in the B layer in the present invention, the M defined above is not preferable if the composition ratio exceeds 30 atomic% because the toughness of the B layer is lowered. More preferably, 3 <e <10.

  Moreover, it is preferable that the film thickness of the said B layer exists in the range of 0.05 micrometer-6 micrometers. If it is less than 0.05 μm, it is difficult to perform stable film formation such as switching of the gas type at the time of film formation and control of the bias voltage, so that film formation is difficult. Since there is a possibility that the later-described merit of alternately laminating and is lost, it is not preferable. More preferably, it exists in the range of 2 micrometers-4 micrometers.

Next, among the alternating layers of the B layer and the C layer, the C layer will be described. The C layer in the present invention is a carbonitride of Ti _f Si _g (where 0 <g <0.3, f + g = 1). The C layer having such a composition exhibits excellent heat resistance and lubricity due to the composition of TiSi, and by using carbonitride, it has a structure in which carbon is dispersed in the coating. Compared with the above, the friction coefficient is low, and the lubricity can be further improved.

  In the C layer in the present invention, if Si is 30 atomic% or more, there is a possibility that the strength of the coating film is lowered, which is a problem. More preferably, 10 <g <25.

  The C layer in the present invention can be formed by a physical vapor deposition method, specifically, an arc ion plating method. Conventionally, since the bias power source is about 30 to 100 V, methane, which is a reactive gas, is used. And acetylene gas was not sufficiently decomposed, and a dense TiSi carbonitride was not obtained. Such a film has a structure in which carbon is partially deposited, resulting in a decrease in heat resistance and strength.

  In the present invention, by setting the bias voltage to a very high value of 200 V or more as a film formation condition for the C layer, both heat resistance and lubricity are excellent and dense TiSi is used. It became possible to form a carbonitride film. It can be said that setting such a high bias voltage is extremely epoch-making in view of conventional technical common knowledge that there is a possibility that the film forming speed may be remarkably reduced when the bias voltage is increased. .

  As described above, by imparting excellent lubricity and heat resistance to the C layer according to the present invention, the cutting edge temperature of the tool can be lowered, and oxidation of the entire coating film can be prevented. Thus, the work material is prevented from welding to the cutting edge, and the roughness of the processed surface is improved.

  Moreover, it is preferable that the film thickness of the said C layer exists in the range of 0.05 micrometer-6 micrometers. If it is less than 0.05 μm, it is difficult to perform stable film formation such as switching of the gas type at the time of film formation and control of the bias voltage, so that film formation is difficult. Since the merit of alternately laminating and may be lost, it is not preferable. More preferably, it exists in the range of 1.0 micrometer-3.0 micrometers.

  In the present invention, the B layer and the C layer described above are alternately laminated. Here, “alternately stacked” refers to an aspect in which the B layer and the C layer are sequentially switched and stacked in a direction orthogonal to the substrate surface. That is, in the orthogonal direction, the layers are laminated in the order of the B layer, the C layer, the B layer, the C layer, and the order of the C layer, the B layer, the C layer, the B layer, and so on. . Here, the layer formed immediately above the A layer may be either the B layer or the C layer, but at least two layers formed directly above the A layer are formed, and the other layer is at least One or more layers are formed. This is because the merit of alternately laminating the B layer and the C layer is obtained.

  For example, when the B layer is laminated directly on the A layer, two or more B layers are laminated, one or more C layers are laminated, and these B layers and C layers are alternately laminated. . Here, the number of layers of the B layer and the C layer is one or more than the C layer. Although the case where the B layer is formed as a layer immediately above the A layer has been described here, the same applies to the case where the C layer is a layer immediately above the A layer.

  In the present invention, by alternately laminating the B layer and the C layer as described above, the performance of the tool can be improved in high speed machining and dry machining. Specifically, in the case of a single layer structure, the entire coating film may be broken or peeled off due to an impact generated during cutting, and there is a problem that the tool life is extremely reduced. Since the layered structure is alternately laminated, the destruction of the coating film due to the impact during cutting can be suppressed between the respective layers, that is, between the B layer and the C layer or between the C layer and the B layer. There is an advantage that the destruction unit of the coating film is reduced. In addition, by adopting such a structure in which the layers are alternately stacked, the difference in lattice constant between the B layer and the C layer can cause distortion in each crystal and increase the hardness.

  In the present invention, the total thickness of the coating film is preferably in the range of 0.5 μm or more and 10 μm or less. If it is less than 0.5 μm, the wear resistance may be reduced, and if it exceeds 10 μm, the toughness of the coating film may be reduced. More preferably, it is 2.5 μm or more and 6.0 μm or less.

  In the present invention, as a method for measuring the thickness of each layer and the thickness of the entire coating layer described above, the tool can be cut and its cross section can be observed using an SEM (scanning electron microscope).

  In the present invention, the uppermost layer of the coating layer can be either a B layer or a C layer. When the B layer is the uppermost layer, the color is black, and when the C layer is the uppermost layer, the color is purple. Therefore, the appearance as a tool can be imparted with design and is commercially useful. .

  In the present invention, in order to coat the coating film on the surface of the base material, it is indispensable to be produced by a film forming process capable of forming a compound having high crystallinity. Therefore, as a result of examining various film forming methods, it is preferable to use a physical vapor deposition method. The physical vapor deposition method includes balanced and unbalanced magnetron sputtering methods, ion plating methods, and the like. Cathode arc ion plating with a high ion ratio of the raw material elements is particularly suitable. When this cathode arc ion plating is used, since the metal ion bombardment treatment can be performed on the surface of the base material before the coating layer is formed, the adhesion between the base material and the coating layer is remarkably improved. This is a preferable process from the viewpoint of adhesion.

(Base material)
The base material in the present invention is a group consisting of WC-based cemented carbide, cermet, high speed steel, ceramics, cubic boron nitride sintered body, diamond sintered body, silicon nitride sintered body, aluminum oxide and titanium carbide. A base material using one or more selected materials.

  In particular, the coated coated cutting tool is preferably a drill, an end mill, a milling or turning cutting edge replaceable tip, a metal saw, a gear cutting tool, a reamer, or a tap.

  This embodiment will explain the surface-coated cutting tool of the present invention in more detail, and further specifically explain how the characteristics such as wear resistance of the tool are improved. In the examples, the composition in the coating film was measured using XPS (X-ray photoelectron spectroscopy analyzer), and the hardness of the coating film was confirmed by a nanoindenter (Nano Indenter XP manufactured by MTS). Moreover, the film thickness in a coating film was measured using SEM as above-mentioned.

  In this embodiment, the coating film of the tool is formed by using the cathode arc ion plating method. However, other than this, for example, the film can also be formed by the balanced or unbalanced sputtering method. Is possible.

<Production of surface-coated cutting tool>
(1) Cleaning of base material As a base material, a cemented carbide end mill (φ10, 6 blades) with a grade of JIS standard K10, a cemented carbide drill (φ8) with a grade of JIS standard K30, and a grade of JIS standard P30. A cemented carbide milling throw-away tip (shape: SDKN42) was prepared and mounted on a cathode arc ion plating apparatus as shown in FIG.

  6 and 7, an arc evaporation source 106, 107, 111 for the A layer, the B layer, and the C layer constituting the coating film and a base material are installed in the chamber 101. A rotary substrate holder 104 is attached. Arc power sources 108 and 109 are attached to the cathodes 106 and 107, respectively. A bias power source 110 is attached to the substrate holder 104. Further, the chamber 101 is provided with a port through which the reaction gas 105 is introduced, and has a structure in which gas can be sucked from the port 103 for adjusting the pressure in the chamber 101 by a vacuum pump.

In the apparatus of FIG. 6, first, the inside of the chamber 101 is depressurized by a vacuum pump, and the temperature is heated to 500 ° C. by a heater installed in the apparatus while rotating the base material. Vacuuming was performed until 10 ⁻⁴ Pa was reached. Next, argon gas was introduced to maintain the pressure in the chamber 101 at 3.0 Pa, and while gradually increasing the voltage of the substrate bias power supply 110, the substrate surface was cleaned for 15 minutes. Thereafter, argon gas was exhausted.

(2) Formation of coating film Next, Ti _a Si _b , Al _c Ti _{d Me} (where M is Si, Cr, V, Y, Zr, B, Zn, Mo and one or more elements selected from the group consisting of Mn), and established a _Ti f Si _g. In addition, the said M used what was selected from the above suitably according to the target composition. Further, the values of a, b, c, d, e, f, g indicating the composition ratio are shown in Table 1 and Table 2 below.

  While the substrate 102 is rotated at the center, while introducing nitrogen gas as a reaction gas, the arc temperature evaporation source 106 is maintained while maintaining the substrate temperature of 500 ° C., the reaction gas pressure of 5 Pa, and the substrate bias voltage of −20V. , 107, and 111, metal ions were generated from a TiSi target set in any one of the layers, and an A layer was formed.

Next, alternating layers of B and C layers were formed. First, in order to form the B layer, N ₂ gas was introduced so that the pressure in the chamber was 2.6 Pa, the substrate temperature was set to 500 ° C., and the base material bias voltage was set to −70V. Then, the AlTiM target was ionized by arc discharge in any one of the arc evaporation sources 106, 107, and 111 and reacted with N ₂ gas to stack (AlTiM) N.

Next, in order to form the C layer, N ₂ gas and CH ₄ gas were introduced so that the pressure in the chamber was 2.6 Pa, the substrate temperature was 500 ° C., and the base material bias voltage was −200 V. A TiSiCN film was formed by ionizing the TiSi target set in any one of 106, 107, and 111 as an arc evaporation source by arc discharge and reacting with N ₂ gas and CH ₄ gas.

  In this way, one or more B layers and C layers were alternately laminated. The layer immediately above the A layer may be either the B layer or the C layer. That is, it is arbitrary whether the B layer is laminated first on the A layer or the C layer is laminated first. Moreover, the film thickness of each layer of A, B, and C can be controlled by controlling the film formation time.

  Table 1 shows the coating film according to the present invention formed as described above, and Table 2 shows the conventional cutting tool.

  Each of the surface-coated cutting tools shown in Table 1 and Table 2 below was evaluated by performing the following tests.

<End mill cutting test>
In the end mill cutting test, a cemented carbide end mill with 6 blades and an outer diameter of 10 mm is used as a base material. 0.025 mm / tooth, cutting depth: Ad = 10 mm, Rd = 0.6 mm, air blow. The tool life was defined as the cutting distance when the wear width on the outer periphery of the cutting edge exceeded 0.1 mm. In this test, the longer the distance, the longer the life.

<Drill cutting test>
In the drill cutting test, a cemented carbide drill with an outer diameter of 8 mm is used as a base material, the work material is S50C, and a hole is drilled therein. Cutting speed: 70 m / min, feed rate: 0.25 mm / rev, hole Depth: The test was carried out under conditions of 30 mm through holes and no cutting oil. The tool life was defined as the number of holes processed when the wear width at the tip margin exceeded 0.2 mm. In this test, the longer the number of holes, the longer the tool life.

<Milling cutting test>
As the milling conditions, a P30-equivalent cemented carbide throw-away tip (shape: SDKN42) was used as a base material, and a direct 160 mm front milling was performed. The work material was SCM435, cutting speed: 250 mm / min, feed rate: 0.3 mm / tooth, cutting amount: 2 mm, and no cutting oil. The tool life was defined as the cutting distance when the wear width of the flank exceeded 0.2 mm. In the test, the longer the distance, the longer the tool life.

  From the results shown in Tables 1 and 2, the surface-coated cutting tool according to the present invention has a significantly improved tool life compared with conventional cutting tools, and has sufficient performance even under severe cutting conditions such as high-speed machining and dry machining. Can be demonstrated.

  Although the embodiments and examples of the present invention have been described as described above, it is also planned from the beginning to appropriately combine the configurations of the above-described embodiments and examples.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic diagram of the blade edge ridgeline part of the conventional cutting tool. It is a schematic diagram shown about the ideal progress of wear of a cutting tool. It is a schematic diagram which shows the example of the chipping which arises in the conventional cutting tool. It is a schematic diagram of the blade edge | tip part of the surface covering cutting tool of this invention. It is sectional drawing cut | disconnected along the VV line | wire of FIG. It is a schematic sectional drawing which shows the example of the apparatus used for the arc ion plating method. FIG. 7 is a schematic top view of the apparatus of FIG. 6.

Explanation of symbols

  1 tool, 2 base material, 3 coating layer, 4 tool rake face, 5 tool rake face, 6 rake face film thickness, 7 flank face film thickness, 8 ridge line thickness, 10 base material exposed part, 11 Oxidized portion of substrate, 12 A layer, alternating layer of 13 B layer and C layer, 101 chamber, 102 substrate, 103 ports, 104 rotary substrate holder, 105 reactive gas, 106, 107, 111 arc Evaporation source, 108, 109 arc power source, 110 bias power source.

Claims (15)

A surface-coated cutting tool comprising a base material and a coating film laminated on the surface of the base material,
The coating film includes an A layer made of a nitride of Ti _a Si _b (where 0 <b <0.3, a + b = 1) formed directly on the substrate, and Al _c Ti _{d Me} (where 0.4 <c <0.75, 0 <e <0.3, c + d + e = 1) (wherein M is selected from the group consisting of Si, Cr, V, Y, Zr, B, Zn, Mo and Mn) B layer made of nitride, carbonitride, nitride oxide or carbonitride of one or more elements and Ti _f Si _g (where 0 <g <0.3, f + g = 1) carbonitride Consisting of C layer,
The B layer and the C layer are alternately laminated on the A layer, and at least one of the B layer and the C layer is laminated, and the other is laminated at least two layers. A surface-coated cutting tool characterized by that.   2. The surface-coated cutting tool according to claim 1, wherein the total thickness of the coating layer is in a range of 0.5 μm to 10 μm.   3. The surface-coated cutting tool according to claim 1, wherein the coating layer has a thickness of the A layer in a range of 0.05 μm to 1.0 μm.   The surface coating according to any one of claims 1 to 3, wherein in the coating layer, the thicknesses of the B layer and the C layer are each independently in the range of 0.05 µm to 6 µm. Cutting tools.   The surface-coated cutting tool according to claim 1, wherein an uppermost layer of the coating layer is a B layer.   The surface-coated cutting tool according to claim 1, wherein an uppermost layer of the coating layer is a C layer.   The substrate is selected from the group consisting of WC-based cemented carbide, cermet, high speed steel, ceramics, cubic boron nitride sintered body, diamond sintered body, silicon nitride sintered body, aluminum oxide and titanium carbide. The surface-coated cutting tool according to claim 1, wherein the surface-coated cutting tool is a base material using one or more of any of the above materials. A method for producing a surface-coated cutting tool comprising a base material and a coating film laminated on the surface of the base material,
Forming a layer A made of a nitride of Ti _a Si _b (where 0 <b <0.3, a + b = 1) directly on the substrate;
Al _c Ti _d M _e (however, 0.4 <c <0.75,0 <e <0.3, c + d + e = 1) ( wherein M is Si, Cr, V, Y, Zr, B, Zn, Mo And B layer of nitride, carbonitride, nitride oxide or carbonitride of one or more elements selected from the group consisting of Mn and Ti _f Si _g (where 0 <g <0.3, a step of alternately laminating C layers made of carbonitride of f + g = 1);
A method for manufacturing a surface-coated cutting tool, comprising:   9. The method for manufacturing a surface-coated cutting tool according to claim 8, wherein the alternately laminating step includes a step of laminating and forming a B layer on the A layer.   The method for manufacturing a surface-coated cutting tool according to claim 8, wherein the alternately laminating step includes a step of laminating and forming a C layer on the A layer.   The method for producing a surface-coated cutting tool according to any one of claims 8 to 10, wherein the alternately laminating step forms one or more of each of the B layer and the C layer.   The surface-coated cutting tool according to any one of claims 8 to 11, wherein the alternately laminating step includes a step of laminating and forming an uppermost layer of the coating layer to be a B layer.   The surface-coated cutting tool according to any one of claims 8 to 11, wherein the alternately laminating step includes a step of laminating and forming a C layer as an uppermost layer of the covering layer.   The step of laminating and forming the A layer is performed using a physical vapor deposition method, in which the bias power source is in the range of 0 to 30 V, the pressure of the nitrogen gas is in the range of 3 to 6 Pa, The method for producing a surface-coated cutting tool according to any one of claims 8 to 13, wherein the material temperature is set to 450 ° C or higher.   15. The method according to claim 8, wherein the step of alternately stacking layers uses a physical vapor deposition method when stacking the C layers, and at that time, a bias voltage is set to 200 V or more. A method for producing a surface-coated cutting tool according to claim 1.

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