JP5922546B2 - Cutting tools - Google Patents

Description

  The present invention relates to a cutting tool having a coating layer formed on the surface of a substrate.

  Currently, for members that require wear resistance, slidability, and fracture resistance, such as cutting tools, wear-resistant members, and sliding members, sintered alloys such as cemented carbide and cermet, diamond, and cBN (cubic boron nitride) A method of improving the wear resistance, slidability or fracture resistance by forming a coating layer on the surface of a high hardness sintered body or a substrate made of a ceramic such as alumina or silicon nitride is used.

  In addition, a coating layer made of a nitride mainly composed of Ti or Al, which is formed by using an ion plating method or a sputtering method as the physical vapor deposition method, has been actively researched to extend the tool life. Improvements continue. These surface-coated tools have been devised in addition to the covering material elements in order to cope with changes in the cutting environment such as an increase in cutting speed and diversification of work materials.

  For example, in Patent Document 1 and Patent Document 2, in the surface coating tool in which the surface of the substrate is coated with a film such as TiAlN by the ion plating method, the absolute value of the negative bias applied during film formation is determined from the initial film formation. Also, a coating film is disclosed in which the Ti content ratio is increased by the cutting blade rather than the flat portion by increasing it at a later stage of film formation.

Japanese Patent Laid-Open No. 01-190383 Japanese Patent Laid-Open No. 08-267306

  However, even in the configuration of the TiAlN film having a high Ti content in the cutting blades described in Patent Document 1 and Patent Document 2, depending on the form of processing, sudden breakage or rapid wear may occur in the cutting blade. .

  This invention is for solving the said subject, The objective is to provide the cutting tool provided with the coating layer which can exhibit the optimal cutting performance for every local.

The cutting tool of the present invention has Al _a M _1-a (C _1-x N _x ) (where M is Ti, Cr, Si, W, Mo, Ta, Hf, Nb, Zr and Y on the surface of the substrate). At least one selected from the group consisting of 0.2 ≦ a ≦ 0.65 and 0 ≦ x ≦ 1), and has a cutting edge at the intersection ridgeline between the rake face and the flank face The Al content ratio in the coating layer at the cutting edge is higher than the Al content ratio in the coating layer at the flank.

According to the cutting tool of the present invention, the coating layer containing Al covering the surface of the substrate has a configuration in which the cutting blade has a higher Al content ratio in the coating layer than the flank. Thereby, the oxidation resistance of the coating layer in a cutting blade can be improved. As a result, even when cutting with severe cutting conditions such as milling tools, drills, end mills, etc., where the temperature of the cutting edge is high, the cutting edge boundary that often occurs with conventional cutting tools It is possible to suppress sudden defects and sudden wear. In addition, since mechanical rubbing wear on the flank can be suppressed, the tool life is extended.

An example of the cutting tool of this invention is shown, (a) Schematic perspective view, (b) It is XX sectional drawing of (a). It is a principal part enlarged view about an example of the coating layer of the cutting tool of FIG.

It demonstrates using FIG. 1 ((a) schematic perspective view, XX sectional drawing of (b) (a)) which is a suitable embodiment example about the cutting tool of this invention.
According to FIG. 1, a cutting tool 1 has a rake face 3 on a main surface, a flank face 4 on a side face, and a cutting edge 5 on a cross ridge line between the rake face 3 and the flank face 4. A coating layer 6 is provided.

The coating layer 6 is Al _a M _1-a (C _1-x N _x ) (where M is at least one selected from Ti, Cr, Si, W, Mo, Ta, Hf, Nb, Zr and Y, 0.2 ≦ a ≦ 0.65, 0 ≦ x ≦ 1).

  In the cutting tool 1 shown in FIG. 1, the Al content in the coating layer 6 in the cutting edge 5 is higher than the Al content in the coating layer 6 in the flank 4. Toward, the Al content ratio in the coating layer 6 is gradually increased. As a result, the oxidation resistance of the coating layer 6 in the cutting edge 5 can be enhanced, and sudden breakage at the boundary of the cutting edge 5 and the rapid progress of wear can be suppressed under the severe cutting conditions of the rotary tool. Moreover, the progress of rubbing wear on the flank 4 can be suppressed.

The specific composition of the coating layer 6 in the cutting edge 5 is Al _a M _1-a (C _1-x N _x ) (where M is Ti, Cr, Si, W, Mo, Ta, Hf, Nb) , Zr and Y, 0.2 ≦ a ≦ 0.65, 0 ≦ x ≦ 1). In the coating layer 6, when a (metal Al composition ratio) is smaller than 0.2, the oxidation resistance and wear resistance of the coating layer 6 are lowered. On the other hand, when a (metal Al composition ratio) is larger than 0.65, the crystal structure of the crystals constituting the coating layer 6 changes from cubic to hexagonal and the wear resistance of the coating layer 6 decreases. A particularly desirable range of a is 0.4 ≦ a ≦ 0.63, and more desirably 0.52 ≦ a ≦ 0.60.

  The metal M is at least one selected from Ti, Cr, Si, W, Mo, Ta, Hf, Nb, Zr, and Y. Among them, at least one of Ti, Cr, Si, Nb, Mo, and W is used. When it contains, it is excellent in hardness and excellent in wear resistance. Further, among them, when the metal M contains one or more of Ti, Cr, Nb, or Si, it is excellent in oxidation resistance at high temperatures. For example, it is harsh using a rotary tool such as a milling tool, a drill, or an end mill. Even when the cutting is performed under the cutting conditions, it is possible to suppress the sudden defect and the rapid progress of wear at the boundary portion of the cutting edge 5.

Further, To illustrate a more specific composition of the coating layer 6 in the cutting edge 5 in the present _{embodiment, Al a Ti b Cr c Nb} d W e (C 1-x N x) (0.2 ≦ a ≦ 0. 65, 0.25 ≦ b ≦ 0.8, 0 ≦ c ≦ 0.4, 0 ≦ d ≦ 0.25, 0 ≦ e ≦ 0.25, a + b + c + d + e = 1, 0 ≦ x ≦ 1). When the coating layer 6 is within this composition range, the coating layer 6 has a higher oxidation start temperature and higher oxidation resistance. Here, when c> 0, that is, when the coating layer 6 contains Cr, the welding resistance of the coating layer 6 is improved. When d> 0, that is, when the coating layer 6 contains Nb, the oxidation start temperature of the coating layer 6 is increased and the oxidation resistance is improved. When e> 0, that is, when the coating layer 6 contains W, internal stress inherent in the coating layer 6 can be reduced, and the fracture resistance of the coating layer 6 is improved. Moreover, the coating layer 6 has high hardness and high adhesion to the substrate 2. For this reason, even under severe cutting conditions of the rotary tool, it is possible to suppress the sudden breakage at the boundary portion of the cutting blade 5 and the rapid progress of wear.

Here, when b (Ti composition ratio) is 0.3 or more, the crystal structure of the coating layer 6 is changed from cubic to hexagonal, and the hardness is not lowered and the wear resistance is high. When b (Ti composition ratio) is 0.8 or less, the coating layer 6 has high oxidation resistance and heat resistance. A particularly desirable range of b is 0.25 ≦ b ≦ 0.51. When c (Cr composition ratio) is 0.4 or less, the welding resistance of the coating layer 6 is improved and the fracture resistance is improved. A particularly desirable range for c is 0.03 ≦ c ≦ 0.2. When d (Nb composition ratio) is 0.25 or less, the oxidation resistance and hardness of the coating layer 6 are not lowered and the wear resistance is high. A particularly desirable range of d is 0.01 ≦ d ≦ 0.2. When e (W composition ratio) is 0.25 or less, the oxidation resistance and hardness of the coating layer 6 are not lowered and the wear resistance is high. A particularly desirable range of e is 0.01 ≦ e ≦ 0.1.

  Further, C and N which are non-metallic components of the coating layer 6 are excellent in hardness and toughness required for the cutting tool. In this embodiment, x (N composition ratio) is 0.9 ≦ x ≦ 1. is there. Here, according to the present invention, the composition of the coating layer 6 can be measured by energy dispersive X-ray spectroscopy (EDX) or X-ray photoelectron spectroscopy (XPS).

  Here, in the present embodiment, the Al content ratio in the coating layer 6 in the cutting edge 5 is higher than the Al content ratio in the coating layer 6 in the rake face 3, and in the present embodiment, from the rake face 3. The Al content in the coating layer 6 increases toward the cutting edge 5. Thereby, the oxidation resistance of the coating layer 6 in the cutting edge 5 of the coating layer 6 is improved. As a result, sudden breakage at the boundary of the cutting edge 5 and rapid progress of wear are suppressed. Moreover, in this embodiment, the Ti content ratio of the coating layer 6 in the flank 4 is high. As a result, the hardness is high and the progress of mechanical rubbing wear is suppressed.

  In this embodiment, the Al content ratio in the coating layer 6 on the flank 4 is higher than the Al content ratio in the coating layer 6 on the rake face 3. Thereby, the oxidation resistance on the rake face 3 is improved, and crater wear on the rake face 3 can be suppressed. Moreover, according to this embodiment, the Ti content ratio of the coating layer 6 is high in the flank 4. As a result, the hardness of the coating layer 6 is increased and flank wear can be suppressed.

Further, in this embodiment, the composition of the coating layer 6 in the cutting edge 5, in the above composition formula _{Al a Ti b Cr c Nb d} W e (C 1-x N x), 0.2 ≦ a ≦ 0.65 0.25 ≦ b ≦ 0.8, 0 ≦ c ≦ 0.4, 0 ≦ d ≦ 0.25, 0 ≦ e ≦ 0.25, a + b + c + d + e = 1, 0 ≦ x ≦ 1). The composition of the coating layer 6 in the flank face 4, in the above composition formula _{Al a Ti b Cr c Nb d} W e (C 1-x N x), 0.19 ≦ a ≦ 0.63,0.27 ≦ b ≦ 0.82, 0 ≦ c ≦ 0.41, 0 ≦ d ≦ 0.25, 0 ≦ e ≦ 0.25, a + b + c + d + e = 1, 0 ≦ x ≦ 1). The composition of the coating layer 6 on the rake face 3, in the above composition formula _{Al a Ti b Cr c Nb d} W e (C 1-x N x), 0.18 ≦ a ≦ 0.61,0.31 ≦ b ≦ 0.82, 0 ≦ c ≦ 0.42, 0 ≦ d ≦ 0.25, 0 ≦ e ≦ 0.25, a + b + c + d + e = 1, 0 ≦ x ≦ 1).

  In the present invention, the range of the cutting edge 5 when specifying the composition and thickness of the coating layer 6 is a region having a width of 500 μm from the intersection of the rake face 3 and the flank face 4 in the cross section of the cutting tool 1. Define. Therefore, the range of the rake face 3 is a region extending from the center of the rake face 3 such as the main surface of the cutting tool 1 to the position of 500 μm from the cross ridge line which is the end of the cutting edge 5, and the range of the flank face 4 is the cutting tool. 1 is a region extending from the center of the flank 4 such as the side surface of 1 to the position of 500 μm from the intersecting ridge line that is the end of the cutting edge 5.

  Here, according to this embodiment, the crystals constituting the coating layer 6 are columnar crystals that are long in the thickness direction, and the average crystal width of the columnar crystals is 200 nm or less. Thereby, even when the surface of the coating layer 6 is exposed to a high temperature, it is possible to suppress the inside of the coating layer 6 from being oxidized, so that the oxidation resistance of the coating layer 6 is further improved. A desirable range of the average crystal width of the columnar crystals is 10 to 200 nm, and particularly desirably 30 to 150 nm. Further, according to this embodiment, the average crystal width of the columnar crystals in the cutting edge 5 is larger than the average crystal width of the columnar crystals in the flank 4. As a result, the fracture resistance of the cutting edge 5 can be increased, and the progress of rubbing wear on the flank can be suppressed. A desirable range of the average crystal width of the columnar crystals in the cutting edge 5 is 50 to 200 nm, and a particularly desirable range is 70 to 150 nm, and a desirable range of the average crystal width of the columnar crystals in the flank 4 is particularly desirably 10 to 150 nm. The range is 30-120 nm. The average crystal width of the columnar crystals in the present invention is the length of a straight line measured by drawing a straight line parallel to the interface between the substrate 2 and the coating layer 6 at a position intermediate the thickness of the coating layer 6 / this straight line. It is calculated by the number of grain boundaries existing in.

  Moreover, in this embodiment of FIG. 2, as shown in the principal part enlarged view about an example of the coating layer 6, the coating layer 6 includes the first coating layer 6a having a high Al content ratio and Al or Al. It consists of a multilayer of two or more layers in which a total of two layers, one layer each with the second coating layer 6b having a low content ratio, are laminated. According to this embodiment, as shown in FIG. It has a multilayer structure in which the second coating layers 6b are alternately stacked. As a result, it is possible to suppress cracks from progressing in the coating layer 6 and to increase the hardness of the entire coating layer 6 and improve the wear resistance. In the present invention, the composition of the coating layer 6 composed of two or more kinds of multilayer structures having different compositions as described above is represented by the overall composition of the coating layer 6 and can be analyzed by an electron beam microanalyzer (EPMA) or the like. . The composition of each of the first coating layer and the second coating layer can be analyzed by energy dispersive X-ray analysis (EDS) attached to a transmission electron microscope (TEM). In order to form the coating layer 6 having the multilayer structure, for example, a sample to be deposited is rotated with targets having different compositions arranged on the inner wall side surface of the chamber of the deposition apparatus with a certain interval. However, it can be produced by forming a film.

Furthermore, in this embodiment, the ratio (t _c / t _f ) between the thickness t _f of the coating layer 6 on the flank 4 and the thickness t _c of the coating layer 6 on the cutting edge 5 is 1.1 to 3. As a result, the tool life can be extended while maintaining a balance between the chipping resistance of the cutting edge 5 and the wear resistance of the flank 4.

In the present embodiment, the thickness of the flank 4 of the coating layer 6 is thicker than the thickness of the rake face 3. Thereby, the wear resistance of the flank 4 is improved, and the tool life can be extended. In the present embodiment, the ratio between the thickness _{t r} of the covering layer 6 in a thickness _{t f} and the rake face 3 of the covering layer 6 in the flank face 4 _(t f / t _r) is 1.2 to 3.

  Moreover, in this embodiment, the granular material called the droplet 7 exists in the surface and the inside of the coating layer 6, as shown in FIG.1 (b). In the present embodiment, the average composition of the droplets 7 existing on the surface of the rake face 3 is higher than the average composition of the droplets 7 existing on the surface of the flank 4.

  According to this configuration, even if chips pass over the rake face 3 during cutting, the presence of the droplets 7 prevents the chips from sticking to the rake face, and the surface of the coating layer 6 does not become so hot. Moreover, since the rake face 3 has a higher Al content in the droplets 7 than the flank face 4, the oxidation resistance of the droplets 7 existing on the rake face 3 is high, and the cutting fluid is applied to the coating layer 6. Also exhibits the effect of retaining liquid on the surface. Further, since the Al content in the droplet 7 is low and the oxidation resistance is low on the flank 4, the flank 4 is worn out and disappears at an early stage, and the finished surface state during processing is improved.

In this embodiment, the Al content ratio Al _DR of the droplet 7 formed on the surface of the rake face 3 of the coating layer 6 is compared with the Al content ratio Al _DF of the droplet 7 formed on the surface of the flank 4. 1.05 ≦ Al _DR / Al _DF ≦ 1.60. Thereby, both the wear resistance on the rake face 3 and the flank face 4 can be optimized.

  Further, the number of the droplets 7 present is 15 to 50, more preferably 18 to 30 droplets 7 having a diameter of 0.2 μm or more in a 10 μm × 10 μm square on the rake face 3. This is desirable in terms of mitigating the heat generated by the passage of chips. Further, the fact that the number of droplets 7 on the rake face 3 is larger than the number of droplets 7 present on the flank face 4 reduces the rake face 3 from becoming hot due to the passage of chips, and It is desirable in terms of improving the finished surface quality by smoothing the surface.

The Ti content ratio Ti _DR of the droplet 7 formed on the surface of the rake face 3 of the coating layer 6 is 0 with respect to the Ti content ratio Ti _DF of the droplet 7 formed on the surface of the flank 4.
. It is desirable that 91 ≦ Ti _DR / Ti _DF ≦ 0.97 because both chipping resistance at the rake face 3 and the flank face 4 can be optimized. A particularly desirable range of the ratio Ti _DR / Ti _DF is 0.94 ≦ Ti _DR / Ti _DF ≦ 0.97. Further, the Cr content ratio Cr _DR of the droplet 7 formed on the surface of the rake face 3 of the coating layer 6 is 1.00 ≦≦ Cr content ratio Cr _DF of the droplet 7 formed on the surface of the flank face 4. Cr _DR / Cr
_DF ≦ 2.5 is desirable in that both wear resistance on the rake face 3 and the flank face 4 can be optimized. A particularly desirable range of the ratio Cr _DR / Cr _DF is 1.00 ≦ Cr _DR / Cr _DF ≦ 1.5.

  The substrate 2 may be a cemented carbide or cermet hard alloy composed of a hard phase mainly composed of tungsten carbide or titanium carbonitride and a binder phase mainly composed of an iron group metal such as cobalt or nickel, or silicon nitride. Hard materials such as ultra-high pressure sintered bodies that fire ceramics and aluminum oxide as a main component, hard phases composed of polycrystalline diamond and cubic boron nitride and binder phases such as ceramics and iron group metals under ultra-high pressure Preferably used.

(Production method)
Next, the manufacturing method of the cutting tool of this invention is demonstrated.

  First, a tool-shaped substrate is produced using a conventionally known method. Next, a coating layer is formed on the surface of the substrate. A physical vapor deposition (PVD) method such as an ion plating method or a sputtering method can be suitably applied as the coating layer forming method. The details of an example of the film forming method will be described. When the coating layer is manufactured by the arc ion plating method, metallic aluminum (Al) and a predetermined metal M (where M is Ti, Cr, Si, W) And at least one selected from Mo, Ta, Hf, Nb, Zr, and Y), each using a metal target, a composite alloy target, or a sintered body target, and set at the side wall surface position of the chamber. .

At this time, a magnet is installed around the target, and a center magnet is installed on the center side of the back surface of the target. According to this invention, the cutting tool of the said embodiment can be produced by controlling the strength of the magnetic force of this magnet. That is, the magnetic force of the center magnet attached to the target having a large Al content ratio is increased, and the magnetic force of the center magnet of the target having no Al content or a low Al content ratio is decreased. Thereby, the diffusion state of the metal ions generated from each target is changed, and the distribution state of the metal ions existing in the chamber is changed. As a result, the content ratio of each metal in the coating layer formed on the surface of the substrate and the presence state of the droplets can be changed. In addition, the number of each target is adjusted so that a coating layer may become a desired composition.

Film formation conditions include using these targets to evaporate and ionize the metal source by arc discharge, glow discharge, or the like, and simultaneously use nitrogen (N ₂ ) gas as a nitrogen source or methane (CH ₄ ) / acetylene as a carbon source ( A coating layer and a droplet are formed by an ion plating method or a sputtering method in which a C ₂ H ₂ ) gas is reacted. At this time, the base is set so that the flank face is substantially parallel to the side face of the chamber and the scoop face is substantially parallel to the upper face of the chamber. At this time, a magnetic force of 2 to 8 T is applied to the center magnet to form a film, but the magnetic force applied to the center magnet provided alongside the target containing Al is applied to a target that does not contain Al or has a low Al content ratio. The film is formed with a higher magnetic force than that applied to the center magnet.

  In forming the coating layer, a high hardness coating layer can be produced in consideration of the crystal structure of the coating layer, and in order to improve the adhesion to the substrate, in this embodiment, the coating layer has a voltage of 35 to 200 V. Apply a bias voltage.

Mainly composed of tungsten carbide (WC) powder having an average particle diameter of 0.8 μm, 10% by mass of metallic cobalt (Co) powder having an average particle diameter of 1.2 μm, and vanadium carbide (VC) powder having an average particle diameter of 1.0 μm. Chromium carbide (Cr ₃ C ₂ ) powder of 0.1% by mass and average particle size of 1.0 μm is added and mixed at a rate of 0.3% by mass, and a KYOCERA cutting tool BDMT11T308TR-JT-shaped throw is formed by press molding. After forming into an away chip shape, a binder removal treatment was performed and fired at 1450 ° C. for 1 hour in a vacuum of 0.01 Pa to produce a cemented carbide. Further, the rake face surface of each sample was polished by blasting, brushing or the like. Further, the prepared cemented carbide was subjected to blade edge processing (honing) by brushing.

  The center magnet shown in Table 1 was set on the first target having a high Al content ratio and the second target having no Al content or a low Al content ratio with respect to the substrate thus prepared. 1 was applied, an arc current of 150 A was applied, and a coating layer having the composition shown in Tables 2 to 3 was formed at a film formation temperature of 540 ° C. The composition of the coating layer was measured by the following method.

With respect to the obtained sample, from the surface of the coating layer, an arbitrary three positions of the coating layer on the cutting edge, the rake face and the flank are observed with a scanning electron microscope (SEM), and energy dispersive spectroscopy analysis ( The composition was analyzed by EDS) (EDAX manufactured by Ametech). The average value of each analysis result was described as the composition of the coating layer. Moreover, about the droplet which exists in the arbitrary three places of each said position, it observes 10 pieces at a time in a big order in each visual field, it measures by an energy dispersive spectroscopy analysis (EDS) (EDEX by Ametec), and covers these average values The composition was calculated as the composition of droplets on the rake face and flank surface of the layer. In the table, the average content (atomic%) of Al, Ti, Cr for droplets formed on the rake face is Al _DR , Ti _DR , Cr _DR , respectively, and Al, Ti, Cr for droplets formed on the flank face. The average content (atomic%) was expressed as Al _DF , Ti _DF , and Cr _DF , respectively, and the ratio of droplets was calculated. Furthermore, the number of droplets having a diameter of 0.2 μm or more in an arbitrary region of 10 μm × 10 μm square in one visual field was measured, and the average number of droplets at three measurement locations was calculated. Moreover, SEM observation was performed about the cross section containing the coating layer of each sample, and the thickness of the coating layer in each position of a cutting edge, a rake face, and a flank was measured. The results are shown in Tables 2-4.

In addition, for the cross section of the coating layer, using the electron backscatter diffraction method, observe the orientation of each crystal constituting the coating layer, identify the crystal grain boundary by expressing the crystals in different directions in different colors,
When the average crystal width of the crystals constituting the coating layer was calculated, Sample No. For 1 to 7, the average crystal width of each sample was 200 nm or less, and the average crystal width at the cutting edge was larger than the average crystal width at the flank.

Next, a cutting test was performed using the obtained throw-away tip under the following cutting conditions. The results are shown in Table 4.
Cutting method: Milling work material: Carbon steel (S45C)
Cutting speed: 200 m / min Feed: 0.15 mm / rev
Cutting depth: 2.0mm
Cutting state: Dry evaluation method: The number of processings that could be performed until the tool life was confirmed, and the state of the cutting blade at that time was confirmed.

  From the results shown in Tables 1 to 4, Sample No. with a higher Al content ratio of the coating layer on the flank face than the cutting edge. In No. 8, the number of machining was small due to a sudden defect at the boundary of the cutting edge. In addition, sample No. 1 in which the Al content ratio of the coating layer on the cutting edge and the flank face is the same. In No. 9, wear progressed early in the boundary portion. On the other hand, Sample No. with a higher Al content ratio of the coating layer in the cutting blade than the flank within the scope of the present invention. In Nos. 1 to 7, abnormal cutting and progress of wear were not observed at the cutting edge boundary, and good cutting performance was exhibited.

DESCRIPTION OF SYMBOLS 1 Cutting tool 2 Base | substrate 3 Rake face 4 Relief face 5 Cutting edge 6 Coating layer 7 Droplet

Claims (7)

AlaM1-a (C1-xNx) (wherein M is at least one selected from Ti, Cr, Si, W, Mo, Ta, Hf, Nb, Zr and Y, 0.2 ≦ a ≦ 0.65, 0 ≦ x ≦ 1) is coated and has a cutting edge at the crossing ridge line between the rake face and the flank face, and Al content in the coating layer in the cutting edge A cutting tool having a ratio higher than the Al content ratio in the coating layer on the flank and a higher Al content ratio in the coating layer on the cutting edge than the Al content ratio in the coating layer on the rake face . The cutting tool of high claim 1 than Al content of the coating layer Al content of the coating layer in the flank in the rake face. The cutting tool according to claim 1 or 2, wherein the crystals constituting the coating layer are columnar crystals that are long in the thickness direction, and the average crystal width of the columnar crystals is 200 nm or less. The cutting tool according to claim 3 , wherein an average crystal width of the columnar crystals in the cutting edge is larger than an average crystal width of the columnar crystals in the flank. Any said coating layer comprises a first coating layer Al content ratio is high, the second covering layer is low or Al content ratio not containing Al and has of claims 1 to 4 comprising two or more layers laminated Or the cutting tool described. The cutting tool according to any one of claims 1 to 5 , wherein a ratio (tc / tf) between a thickness tf of the coating layer on the flank and a thickness tc of the coating layer on the cutting edge is 1.1 to 3 . The cutting tool according to any one of claims 1 to 6 , wherein a ratio (tf / tr) of a thickness tf of the coating layer on the flank and a thickness tr of the coating layer on the rake face is 1.5 to 3.

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