JP4268558B2 - Coated cutting tool - Google Patents

Description

  The present invention relates to cutting tools such as drills, end mills, milling and turning cutting edge-replaceable tips, metal saws, gear cutting tools, reamers, taps, etc., and in particular, cutting in which a coating with improved chipping resistance is formed on the surface thereof. It relates to tools.

  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. Therefore, the tool edge temperature tends to be higher and the tool life is shortened. As a result, the characteristics required for the tool material are becoming stricter.

In Patent Document 1 listed below, a hard coating layer is provided on the surface of a hard base material such as a cutting tool such as a WC-based cemented carbide, cermet, high-speed steel, or wear-resistant tool in order to improve wear resistance and surface protection function. (Al _x Ti _1-xy Si _y ) (C _z N _1-z ) where 0.05 ≦ x ≦ 0.75, 0.01 ≦ y ≦ 0.1, 0.6 ≦ z ≦ 1 is coated with an AlTiSi-based film.

  However, the cutting tool described in Patent Document 1 has high hardness and excellent oxidation resistance, but has a problem in that it is brittle and easy to chip.

On the other hand, for example, according to Patent Document 2 below, a nitride, carbonitride, oxynitride, oxycarbonitride, and nitriding mainly composed of Ti and Al containing Ti in an appropriate amount are included. In a nitride, carbonitride, oxynitride, oxycarbonitride having a fine structure such as TiSi-based compound, carbonitride, oxynitride, oxycarbonitride, It is disclosed that the performance of a cutting tool is extremely good in dry high-speed cutting when coating one or more layers alternately so that Si ₃ N ₄ and Si exist as independent phases.

  According to this patent document 2, in the conventional TiAlN film, the alumina layer formed by the surface oxidation that occurs in the cutting process functions as an oxidation protective film against the inward diffusion of oxygen, but in the dynamic cutting process, The alumina layer of the present invention peels off more easily than the porous Ti oxide layer directly below it and is not sufficient for the progress of oxidation. However, the TiSi coating of the present invention not only has extremely high oxidation resistance of the film itself. It is shown that a very dense composite oxide of Ti and Si containing Si is formed on the outermost surface, so that the porous Ti oxide layer, which has been a problem in the past, is not formed, so that the performance is improved. Furthermore, if it is important to coat the TiSi film directly on the TiAl film, the order of coating is also defined.

Further, according to Patent Document 3 below, as a film having better wear resistance than a TiAlN film, a film made of (Al _b [Cr _1−α V _α ] _c ) (C _1−d N _d ), or (M _a Al _b [Cr _1-α V _α ] _c ) (C _1-d N _d ) (M is composed of Ti, Nb, W, Ta, Mo) is disclosed. By adding Cr and V while increasing the content of Al among the metal components, cubic AlN, which is a metastable phase at normal temperature and pressure, is formed, improving high hardness and oxidation resistance. I am letting.

  However, in order to perform high-speed, high-efficiency machining and dry machining that does not use a lubricant completely in the cutting process, high hardness and the above-described coating stability at high temperatures are not sufficient. That is, it is a problem how to maintain a film having excellent characteristics on the surface of the base material for a long period of time without causing peeling or defects.

  In order to facilitate understanding of the wear of a general cutting tool, this will be described with reference to FIG. FIG. 1A shows a schematic cross-sectional view of a typical cutting edge of a cutting tool. In FIG. 1A, the cutting edge of the cutting tool has a configuration in which a coating film is formed on the surface of a base material. The cutting edge is constituted by a rake face and a flank face, and in many cases the angle is an acute angle or a right angle. When a film is formed on such a tool blade edge, as shown in the figure, the film tip end portion c is the thickest as compared with the rake face film thickness a and the flank face film thickness b.

  Next, ideal progress of wear at the cutting edge will be described with reference to FIGS. Ideal wear as a tool is as follows. First, the coating gradually wears as shown in FIG. 1 (b), and eventually reaches the substrate as shown in FIG. 1 (c). Thus, the film and the substrate are both exposed and worn.

However, as a result of detailed investigation of the tool wear portion by the present inventors, the wear of the blade tip does not proceed as described above, and the tip of the blade tip has already reached the substrate as shown in FIG. It was found that the substrate had disappeared (the substrate was completely exposed) and chipped (or lost) due to its morphology. In addition, the base material surface of that part has already been oxidized, and no matter how much the oxidation resistance of the film and the high hardness and wear resistance are good as in the above patent document, the base material must be exposed at the initial stage of cutting. It is considered difficult to significantly improve the tool life.
Japanese Patent No. 2793773 Japanese Patent No. 3347687 JP 2003-34859 A

  The present invention has been made to solve the above-described problems of the prior art, and its purpose is to improve the oxidation resistance of a coating in a cutting tool under severe conditions such as high speed and dry processing. An object of the present invention is to provide a coated cutting tool capable of suppressing chipping (or chipping) of a cutting edge that occurs in the early stage of cutting, that is, exposure of a base material and improving tool life.

In the present invention, the surface of the base material is coated with at least one wear-resistant film of nitride or carbonitride of Ti _1-x Al _x (where 0.2 ≦ x ≦ 0.7). A nitride or charcoal of Al _1-ab Cr _a V _b (where 0 ≦ a ≦ 0.4, 0 ≦ b ≦ 0.4, a + b ≦ 0.4) is formed on the surface of the wear-resistant coating. A coated cutting tool coated with at least one chipping-resistant coating of nitride, wherein the wear-resistant coating is thicker than the chipping-resistant coating. A coated cutting tool is provided.

Preferably, the chipping-resistant film is a nitride or charcoal of Al _1-ab Cr _a V _b (where 0 ≦ a ≦ 0.4, 0 <b ≦ 0.4, a + b ≦ 0.4). Any one or more of nitrides.

  Preferably, Si and / or B is contained in the wear-resistant film and / or chipping-resistant film in the range of 0.01% to 10% by atomic%.

  Preferably, the film thickness of the abrasion-resistant coating is in the range of 2 μm to 10 μm.

  Preferably, the film thickness of the wear resistant film is 1.5 times or more of the film thickness of the chipping resistant film.

  Preferably, the crystal structure of the oxidation resistant coating and the chipping resistant coating is cubic.

  Preferably, the substrate is a WC-based cemented carbide, cermet, high-speed steel, ceramics, cubic boron nitride sintered body, diamond sintered body, silicon nitride sintered body, or aluminum oxide and titanium carbide. Any of the mixtures consisting of

  Preferably, the coated cutting tool of the present invention is used for any of a drill, an end mill, a milling and turning cutting edge replaceable tip, a metal saw, a gear cutting tool, a reamer, or a tap.

  Preferably, the coated cutting tool of the present invention is coated by physical vapor deposition.

  Preferably, the coated cutting tool of the present invention is coated by an arc ion plating method or a magnetron sputtering method.

According to the coated cutting tool of the present invention, the main component is Al that does not contain Ti in the coating (Al _1-a-b Cr _a V _b ) (where 0 ≦ a ≦ 0.4, 0 ≦ b ≦). 0.4, a + b ≦ 0.4) Any one or more of chipping-resistant coatings of nitride and carbonitride are formed on the outermost surface layer of the tool. As shown in FIG. 1 (f), the wear-resistant layer immediately above the base material is not damaged, and the film wears, and the chipping of the wear-resistant film, which has been a problem until now, can be suppressed. Can be achieved. Further, the chipping of the wear-resistant layer can be suppressed by making the film thickness of the wear-resistant film thicker than the film thickness of the chipping-resistant film.

The coated cutting tool of the present invention has at least one type of wear resistance of nitride or carbonitride of Ti _1-x Al _x (where 0.2 ≦ x ≦ 0.7) on the surface of the base material. A coating is applied, and Al _1-ab Cr _a V _b (where 0 ≦ a ≦ 0.4, 0 ≦ b ≦ 0.4, a + b ≦ 0.4) is formed on the surface of the wear-resistant coating. One or more types of chipping resistant coatings of nitride or carbonitride are coated, and the thickness of the wear resistant coating is larger than the thickness of the chipping resistant coating.

In particular, the coated cutting tool of the present invention is (i) a nitride or carbonitride of (Ti _1-x Al _x ) (0.2 ≦ x ≦ 0.7) containing Ti as an essential component as a wear-resistant coating. Any one or more of the above are formed so as to directly cover the surface of the substrate, and (ii) Ti is not included so as to cover the surface of the wear-resistant coating (Al _1-a-b Cr _a V _b ) (where 0 ≦ a ≦ 0.4, 0 ≦ b ≦ 0.4, a + b ≦ 0.4) and one or more types of chipping resistant coatings of nitride or carbonitride are coated. And (iii) the requirements of (i) to (iii) of making the film thickness of the abrasion-resistant film thicker than the film thickness of the chipping-resistant film act synergistically, As a result, the life of the coated cutting tool is improved.

  In the coated cutting tool of the present invention, since the wear-resistant coating contains Ti, the adhesion with the substrate is improved. Therefore, the coating directly covering the substrate requires Ti as a constituent element. Further, since the oxidation resistance is improved by containing Al in the wear-resistant coating, the Al amount x is set in the range of 0.2 ≦ x ≦ 0.7. The presence of Al in the oxidation resistant coating is preferable because the oxidation resistance of the coating is improved. However, if x exceeds 0.7, the crystal structure becomes hexagonal and the hardness of the coating is reduced, so that wear is reversed. Promoted. On the other hand, if the Al content is less than 0.2, there is a problem that the oxidation resistance and the hardness cannot be increased. More preferably, 0.3 ≦ x ≦ 0.6.

On this wear-resistant film, as a chipping-resistant film, (Al _1-a-b Cr _a V _b ) (where 0 ≦ a ≦ 0.4, 0 ≦ b ≦ 0.4, a + b ≦ 0 .4) Any one or more of nitride and carbonitride are coated. Here, it is characterized by not containing Ti as a metal component but mainly containing Al. The inclusion of Al is preferable because the oxidation resistance is improved, the thermal conductivity is increased, and heat generated during cutting can be released from the tool surface. In addition, it is thought that it is caused by the lubrication performance on the surface, but the welding resistance to the work material is improved compared to the coating film containing Ti, so that it is possible to suppress the peeling of the coating film along with the welded material, and the cutting resistance is also reduced. In addition, chip discharge can be improved. Here, in (Al _1-a-b Cr _a V _b ), the amounts of Cr and V excluding Al are set to 0 ≦ a ≦ 0.4, 0 ≦ b ≦ 0.4, and 0 ≠ a + b ≦ 0. The range is 4. a and b are defined as 0 ≦ a ≦ 0.4 and 0 ≦ b ≦ 0.4 (where 0 ≠ a + b ≦ 0.4). When a and b exceed 0.4, chipping resistance This is because the hardness of the adhesive coating is lowered and there is a problem in wear resistance. If V is present in the chipping-resistant film, the surface of the coating is oxidized in a high temperature environment at the time of cutting. At this time, since the oxide of V has a low melting point, it acts as a lubricant at the time of cutting and acts as a work material. This is preferable because an effect of suppressing adhesion can be expected. Further, when Cr is contained in the chipping-resistant film, the Cr oxide is dense, and there is an effect of suppressing inward diffusion of oxygen. More preferably, 0 ≦ a ≦ 0.4, 0 <b ≦ 0.4, and a + b ≦ 0.4. Here, the reason for setting 0 <b is that V is present in the film as an essential component so as to reliably suppress adhesion of the work material.

  Further, the addition of Cr and V is preferable in that a cubic Al compound that is a metastable phase at normal temperature and pressure can be formed. For example, in the case of AlN that is a nitride, the estimated lattice constant in the case of a cubic crystal that is usually a hexagonal crystal but a metastable phase is 4.12%, whereas the cubic crystal is normal temperature and pressure. The lattice constant of CrN and VN, which are stable phases, is 4.14 Å, which is very close to cubic AlN. Therefore, AlN becomes cubic due to the pulling effect, thereby increasing the hardness. Therefore, the crystal structure of the film is preferably cubic. The crystallinity of the coating can be measured by an X-ray diffraction method.

  In the present invention, the thickness of the wear-resistant film is larger than the film thickness of the chipping-resistant film. When the wear-resistant film is thin and the chipping film is thick, if the film is chipped at the cutting edge shown in FIG. Since chipping is performed simultaneously, it is not preferable. In particular, from the viewpoint of suppressing chipping, the film thickness of the abrasion-resistant film is preferably 1.5 times or more than the film thickness of the chipping-resistant film. When the thickness of the wear resistant coating is less than 1.5 times the thickness of the chipping resistant coating, as described above, when chipping occurs in the upper chipping resistant coating, the lower wear resistant coating Is also chipping at the same time. More preferably, it is twice or more.

In the present invention, the above-mentioned wear-resistant coating and chipping-resistant coating may each be composed of a plurality of layers. That is, the range of this component in any one or more of the above-mentioned components (Ti _1-x Al _x ) (0.2 ≦ x ≦ 0.7) and carbonitrides constituting the abrasion-resistant film A plurality of films having different blends can be formed to form a wear-resistant film as a whole. Also in the chipping-resistant coating, the nitriding of the component (Al _1-a-b Cr _a V _b ) (where 0 ≦ a ≦ 0.4, 0 ≦ b ≦ 0.4, a + b ≦ 0.4) In any one or more of the above materials and carbonitrides, a plurality of films having different compositions within the range of this component can be formed to form a chipping resistant coating as a whole.

  In the present invention, Si may be contained in the wear-resistant film and / or chipping-resistant film. It is because film hardness improves by containing Si. Specifically, when Si is present in the film, the film structure is refined from a columnar shape of 500 nm to 250 nm to a needle shape of 100 nm or less, and the hardness of the film is improved. The Si content is in the range of 0.01% or more and 10% or less in atomic percent with respect to the entire coating. If the Si content is less than 0.01%, the film becomes hard, but the film itself becomes brittle, cracking or peeling occurs inside the film, and wear may be accelerated. On the other hand, if the Si content exceeds 10%, a problem arises that cracking occurs during firing of the target, and the material strength that can be used for coating cannot be obtained. More preferably, it is 0.03% or more and 6% or less.

  In the present invention, B may be contained in the wear-resistant coating and / or chipping-resistant coating in an atomic percent of less than 10%. When B is contained in the wear-resistant coating and / or chipping-resistant coating, the mechanism is not known, but a coating with higher hardness is preferable. Further, the oxide of B formed by surface oxidation during cutting is particularly preferable because it densifies the oxide of Al. Further, since the oxide of B has a low melting point, it acts as a lubricant during cutting, and exhibits the effect of suppressing the adhesion of the cutting edge and the generation of the constituent cutting edge.

  In the present invention, the thickness of the wear-resistant coating film is 2 μm or more and 10 μm or less. If the film thickness is less than 2 μm, improvement in wear resistance is not observed. Conversely, if the film thickness exceeds 10 μm, the residual stress in the surface peritoneum increases and the adhesion strength with the substrate decreases, which is not preferable. Furthermore, from the viewpoint of wear resistance, the film thickness of the wear-resistant film is preferably 2.5 μm or more and 6 μm or less. As a method for measuring the film thickness, it can be obtained by cutting a tool and observing the cross section with an SEM (scanning electron microscope).

In this invention, it is preferable that the compressive residual stress of the said abrasion-resistant film is -6 GPa or more and 0 GPa or less. If it exceeds 0 GPa, a tensile stress remains in the coating, which causes a problem that the film tends to crack and the chipping property is lowered. On the other hand, if it is less than -6 GPa, the residual stress in the peritoneum is increased, and the adhesion strength with the substrate is lowered, which is not preferable. More preferably, it is -4 GPa or more and -2 GPa or less. The compressive residual stress can be controlled by adjusting the film formation temperature, the film formation pressure, and the substrate bias voltage for a film having the same composition. For example, as the substrate bias voltage increases, the compressive residual stress increases. Becomes higher (bias voltage up to 200V). Such compressive residual stress can be measured by the 2θ-sin ² ψ method using X-rays. Here, θ represents the diffraction angle, ψ represents the angle formed by the sample surface normal and the lattice surface normal, and 2θ−sin ² ψ can determine the stress from the gradient of the diagram. For details, see pages 156 to 158 of PVD / CVD coating basics and applications edited by Surface Technology Association.

  The substrate in the present invention includes WC-based cemented carbide, cermet, high speed steel, ceramics (silicon carbide, silicon nitride, aluminum nitride, aluminum oxide, etc.), cubic boron nitride sintered body, diamond sintered body, nitrided Any of a silicon sintered body and a base material made of aluminum oxide and titanium carbide can be used. In particular, the coated cutting tool is preferably a drill, an end mill, a milling and turning cutting edge replaceable tip, a metal saw, a gear cutting tool, a reamer, a tap, or the like.

  In order to coat the surface of the substrate with the wear-resistant coating in the present invention, it is indispensable to produce it by a film forming process capable of forming a compound having high crystallinity. Thus, as a result of examining various film forming methods, the present inventors have found that it is preferable to use a physical vapor deposition method. Physical vapor deposition methods include balanced and unbalanced magnetron sputtering methods, ion plating methods, and the like. Cathode arc ion plating with a high ion ratio of raw material elements is particularly suitable. When this cathode arc ion plating is used, metal ion bombardment treatment can be performed on the surface of the substrate before forming the wear-resistant coating, so the adhesion of the coating is greatly improved. This is also a preferable process.

  Next, the coated cutting tool of the present invention will be described in more detail using examples. The composition in the examples was confirmed by an X-ray photoelectron spectrometer (XPS) (PHI Quantera SXM, ULVAC-PHI), and the hardness was confirmed by a nanoindenter (Nano Indenter XP, manufactured by MTS). The peritoneum can also be formed by a balanced or unbalanced sputtering method other than the cathode arc ion plating method described below.

(Examples 1 to 23, Comparative Examples 1 and 2)
(1) Production of coated cutting tool A cemented carbide alloy with a grade of JIS standard P30 and a chip shape of SPGN120308 with a JIS standard were prepared as a base material and attached to a cathode arc ion plating apparatus.

First, the inside of the chamber is depressurized by a vacuum pump, and the substrate is heated to a temperature of 650 ° C. by a heater installed in the apparatus, and evacuation is performed until the pressure in the chamber reaches 1.0 × 10 ⁻⁴ Pa. It was. Next, argon gas was introduced to maintain the pressure in the chamber at 3.0 Pa, and while gradually increasing the voltage of the substrate bias power source, the surface of the substrate was cleaned for 15 minutes while being set to −1500 V. Thereafter, argon gas was exhausted.

  Next, while introducing an alloy target that is a metal evaporation source of the wear-resistant coating component and a gas for obtaining the coating of the present invention among nitrogen, methane, and oxygen as a reactive gas, the substrate temperature is 650 ° C., the reactive gas pressure is While maintaining 2.0 Pa and the substrate bias voltage at -70 V, an arc current of 100 A was supplied to the cathode electrode, and metal ions were generated from the arc evaporation source to form a coating. Then, the current supplied to the evaporation source was stopped when the predetermined film thickness was reached.

  Subsequently, a chipping-resistant film was continuously formed. While introducing an alloy target which is a metal evaporation source of the coating component and a gas for obtaining the coating of the present invention out of nitrogen, methane and oxygen as the reaction gas, the substrate temperature is 650 ° C., the reaction gas pressure is 2.0 Pa, the substrate While maintaining the bias voltage at −200 V, an arc current of 100 A was supplied to the cathode electrode, and metal ions were generated from the arc evaporation source to form a coating. Then, the current supplied to the evaporation source was stopped when the predetermined film thickness was reached. Here, the film formation conditions are constant, but even with a film having the same composition, the film hardness and residual stress value can be controlled by controlling the substrate temperature, reaction gas pressure, and substrate bias voltage. It is.

  Usually, the cooling is performed as it is. However, the substrate may be rapidly cooled by introducing He gas or the like at the same time as the completion of the coating to fill the chamber. Although the mechanism is not completely understood, the rapid cooling treatment refines the crystal grains in the film and makes them finer from a columnar structure to a needle-like structure, increasing the amount of elastic recovery of the film, and chipping resistance. It is for improving.

(2) Coated cutting tool life evaluation For each of the coated cutting tools of Examples 1 to 23 and the cutting tools of Comparative Examples 1 and 2 which are samples manufactured in the above-described steps, dry continuous turning is actually performed under the conditions shown in Table 3. The test and the intermittent turning test were performed, and the flank wear width of the cutting edge was measured. The life evaluation results are shown in Tables 1 and 2. However, the results in Table 2 assume that the chipping resistant coating contains Si or B atoms.

  As is clear from Tables 1 and 2, it was confirmed that the cutting tool life was greatly improved in the present invention.

(Examples 24-26, Comparative Examples 3 and 4)
In exactly the same manner as in Example 1, each of the 8 mm outer diameter drills (JISK10 cemented carbide) was coated, and the same coatings as in Examples 1, 6, 20 and Comparative Examples 1 and 2 were coated. The obtained samples were used as the coated cutting tools of Examples 24-26 and Comparative Examples 3 and 4. Next, using these samples, drilling of SCM440 (HRC30) was actually performed to evaluate the life. Cutting conditions were a cutting speed of 90 m / min, a feed amount of 0.2 mm / rev, no cutting fluid (using air blow), and a blind hole with a depth of 24 mm. Note that the life was determined when the dimensional accuracy of the workpiece was outside the specified range. The life evaluation results are shown in Table 4.

  As a result, it was confirmed that the life of the drill of the present invention was greatly improved.

(Examples 27 to 29, Comparative Examples 5 and 6)
By coating the 6-flute end mill (JISK10 cemented carbide) with an outer diameter of 8 mm by coating the coatings of Examples 1, 6 and 20 and Comparative products 1 and 2, respectively, in exactly the same manner as in Example 1. The coated cutting tools of Examples 27 to 29 and the coated cutting tools of Comparative Examples 5 and 6 were obtained. Next, using these coated cutting tools, end mill side milling of SKD11 (HRC60) was actually performed to evaluate the life. Cutting conditions were a cutting speed of 200 m / min, a feed of 0.03 mm / blade, a cutting amount Ad = 12 mm, Rd = 0.2 mm, and side cutting was performed without using a cutting fluid (using air blow). Note that the life was determined when the dimensional accuracy of the workpiece was outside the specified range. The life evaluation results are shown in Table 4 above.

  As a result, it was confirmed that the life of the end mill of the present invention was greatly improved.

(Examples 30 to 32, Comparative Examples 7 and 8)
First, using a cemented carbide pot and balls, a binder powder composed of 40% TiN and 10% Al by weight and 50% cBN powder having an average particle diameter of 2.5 μm are mixed together to form a cemented carbide container. And sintered at a pressure of 5 Gpa and a temperature of 1400 ° C. for 60 minutes. This cBN sintered body was processed to obtain a cutting tip having a shape of ISO standard SNGA120408.

  The chips were coated with the coating films of Examples 1, 6, 20 and Comparative Products 1 and 2 in exactly the same manner as in Example 1, and the coated cuttings of Examples 30 to 32 and Comparative Examples 7 and 8, respectively. I got a tool. Using the coated cutting tool, the outer peripheral cutting of SUJ2 round bar (HRC62), which is a kind of hardened steel, was performed. Cutting was performed under the conditions of a cutting speed of 120 m / min, a cutting depth of 0.2 mm, a feed of 0.1 mm / rev, and a dry method for 40 minutes, and the flank wear amount was examined. The results are shown in Table 3, and it was confirmed that the life of the cutting tip of the present invention was greatly improved.

(Example 33, Comparative Examples 9 and 10)
Cemented carbide with grade JIS standard S20, chip shape with JIS standard CNMG120408 base material prepared, and the coating film used in Example 20 which is a cutting tool manufactured in the same process as Example 1 The coating films used in Comparative Examples 1 and 2 were coated on the substrate, and the corresponding cutting tools were the coated cutting tool of Example 33 and the cutting tools of Comparative Examples 9 and 10, respectively. Each cutting tool was actually subjected to a wet (water-soluble emulsion) continuous turning test under the following conditions, and the time when the flank wear width of the cutting edge exceeded 0.2 mm was measured. Cutting conditions were a work material and a Ti alloy Ti-6Al-4V (HB = 310), a cutting speed of 80 m / min, a feed amount of 0.2 mm / rev, and a cutting depth of 1 mm. As a result, the cutting tool of Example 33 was capable of cutting for 30 minutes, whereas the cutting tool of Comparative Example 9 was cut in 4 minutes and the cutting tool of Comparative Example 10 was chipped in 1 minute. Interrupted. From this, it was confirmed that the life of the cutting tip of the present invention has been greatly improved.

  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 cross-sectional schematic diagram of a typical cutting edge of a general cutting tool.

Claims (10)

The surface of the substrate is coated with at least one wear-resistant film of nitride or carbonitride of Ti _1-x Al _x (where 0.2 ≦ x ≦ 0.7), and the wear resistance to the surface of sexual _film, any of _{Al 1-a-b Cr a} V b ( However, 0 ≦ a ≦ 0.4,0 ≦ b ≦ 0.4, a + b ≦ 0.4) nitride or carbonitride A coated cutting tool coated with at least one kind of chipping-resistant coating, wherein the wear-resistant coating has a thickness greater than that of the chipping-resistant coating. tool. The chipping resistant coating is made of a nitride or carbonitride of Al _1-ab Cr _a V _b (where 0 ≦ a ≦ 0.4, 0 <b ≦ 0.4, a + b ≦ 0.4). The coated cutting tool according to claim 1, wherein one or more of them are used.   The wear-resistant coating and / or chipping-resistant coating contains Si and / or B in an amount of 0.01% or more and 10% or less in atomic percent with respect to the entire coating. Item 3. A coated cutting tool according to item 1 or 2.   The coated cutting tool according to any one of claims 1 to 3, wherein the wear-resistant coating has a thickness in a range of 2 µm to 10 µm.   The coated cutting tool according to any one of claims 1 to 4, wherein a film thickness of the wear-resistant coating film is 1.5 times or more of a film thickness of the chipping-resistant coating film.   The coated cutting tool according to any one of claims 1 to 5, wherein the crystal structures of the oxidation-resistant coating and the chipping-resistant coating are cubic.   The base material is a WC-based cemented carbide, cermet, high-speed steel, ceramics, cubic boron nitride sintered body, diamond sintered body, silicon nitride sintered body, or a mixture of aluminum oxide and titanium carbide. The coated cutting tool according to claim 1, wherein the coated cutting tool is a body.   The coated cutting tool according to any one of claims 1 to 7, wherein the coated cutting tool is used for any one of a drill, an end mill, a milling and turning cutting edge replaceable tip, a metal saw, a gear cutting tool, a reamer, or a tap. .   The coated cutting tool according to any one of claims 1 to 8, which is coated by a physical vapor deposition method.   The coated cutting tool according to any one of claims 1 to 9, wherein the coated cutting tool is coated by an arc ion plating method or a magnetron sputtering method.

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