JP2011005559A - Coated tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated tool capable of achieving long life in cutting processing under severe processing conditions such as high-speed processing, high-feed processing, and processing of a hard-to-cut material.SOLUTION: The coated tool is formed of a base material and a coating film coated on the surface thereof. The compressive residual stress σof the base material obtained by X-ray stress measurement using a Cr-Kα line is larger than the compressive residual stress σof the base material obtained by X-ray stress measurement using a Co-Kα line.

Description

The present invention relates to a coated tool in which a surface of a base material such as a sintered alloy, ceramics, cBN sintered body, diamond sintered body, etc. is coated.

As a conventional technique of a coated tool in which a coating of TiC, TiCN, TiN, (Ti, Al) N, CrN or the like is coated on the surface of a base material such as a sintered alloy, ceramic, or cBN sintered body, a first coating, A surface-coated cutting tool comprising a coating comprising a second coating and a substrate, wherein the first coating is composed of α-type aluminum oxide and has a residual stress of less than 0.2 GPa The second film is a group consisting of at least one element selected from the group consisting of group IVa elements, group Va elements, group VIa elements, Al and Si of the periodic table, and carbon, nitrogen, oxygen and boron. There is a surface-coated cutting tool characterized in that it is composed of at least one selected from the above and has a compressive residual stress (see, for example, Patent Document 1). However, this surface-coated cutting tool has a problem that the adhesion between the coating and the substrate is poor.

JP 2006-192531 A

In recent years, a long life of a coated tool is demanded in severe cutting conditions such as severe cutting conditions such as high speed and high feed and high hardness of a work material in cutting. The present invention has been made under such circumstances, and an object of the present invention is to provide a coated tool that achieves a long service life in cutting processing with severe processing conditions such as high-speed processing, high-feed processing, and processing of difficult-to-cut materials.

Adhesion between the substrate and the coating is a very important factor that affects the performance of the coated tool. The inventor studied the influence of the residual stress on the adhesion between the base material and the coating, and more than the compressive residual stress σ _bCo of the base material obtained by the X-ray stress measurement using Co-Kα rays. The knowledge that the adhesiveness of a base material and a film improves when the compression residual stress (sigma) _bCr of the base material obtained by the X-ray-stress measurement using a Cr-K alpha ray was enlarged was acquired.

That is, the coated tool of the present invention comprises a substrate and a film coated on the surface thereof, and the compression residual stress σ _bCr of the substrate obtained by X-ray stress measurement using Cr—Kα rays is Co— This is a coated tool that is larger than the compressive residual stress σ _bCo of the base material obtained by X-ray stress measurement using Kα rays.

Specific examples of the base material for the coated tool of the present invention include sintered alloys, Si ₃ N ₄ ceramics, Al ₂ O ₃ ceramics, cBN sintered bodies, and diamond sintered bodies. Of these, sintered alloys are preferable because they are excellent in fracture resistance and wear resistance. Among them, cermets and WC-based cemented carbides are more preferable, and among them, WC-based cemented carbides are more preferable.

In the present invention, the residual stress is an internal stress remaining in the coating and the substrate, and is a concept including both compressive residual stress and tensile residual stress. In the present invention, the compressive residual stress is represented by a numerical value “−” (minus). In the present invention, a large compressive residual stress means that the absolute value of the compressive residual stress is large. Conversely, in the present invention, the small compressive residual stress means that the absolute value of the compressive residual stress is small. In the present invention, the tensile residual stress is represented by a numerical value “+” (plus).

σ：残留応力
Ｅ：ヤング率
ν：ポアソン比
θ₀：標準ブラッグ角
2θ：回折線の回折角度
Ψ：試料面法線と回折面法線のなす角

ここで、（数２）におけるＫは応力定数と呼ばれ、測定材料と測定波長によって決まる定数である。測定値（Ψ，2θ）から2θ-sin²Ψ図を書き、最小二乗法で勾配∂(2θ)/∂(sin²Ψ)を求め、Ｋを乗ずれば残留応力σが求められる。なお、Ｘ線出力（電圧、電流）は測定材料に応じて適宜調整するとよい。 The residual stress σ of the substrate and the coating of the present invention can be calculated from (Equation 1) of the 2θ-sin ² Ψ method using an X-ray stress measuring device.

σ: Residual stress E: Young's modulus ν: Poisson's ratio θ ₀ : Standard Bragg angle
2θ: Diffraction angle of diffraction line Ψ: Angle between sample surface normal and diffraction surface normal

Here, K in (Equation 2) is called a stress constant and is a constant determined by the measurement material and the measurement wavelength. A 2θ-sin ² Ψ diagram is written from the measured values (Ψ, 2θ), the gradient ∂ (2θ) / ∂ (sin ² Ψ) is obtained by the least square method, and the residual stress σ is obtained by multiplying by K. Note that the X-ray output (voltage, current) may be appropriately adjusted according to the measurement material.

The penetration depth of X-rays varies depending on the wavelength of X-rays used for X-ray stress measurement. The shorter the X-ray wavelength, the deeper the X-ray penetration depth, and the longer the X-ray wavelength, the shallower the X-ray penetration depth. Therefore, among the Cu-Kα ray having a wavelength of 1.54056Å, the Co-Kα ray having a wavelength of 1.78897Å, and the Cr-Kα ray having a wavelength of 2.28897Å, the Cu-Kα ray is the deepest inside. Residual stress can be measured, the residual stress in the Co-Kα line shallower than the Cu-Kα line can be measured, and the residual stress in the Cr-Kα line shallower than the Co-Kα line can be measured. The residual stress obtained by X-ray stress measurement is an average value of residual stress up to the penetration depth of X-rays.

When the residual stress of the base material of the present invention is measured using the Co-Kα ray and the Cr-Kα ray, the Cr-Kα ray is used rather than the compressive residual stress σ _bCo obtained using the Co-Kα ray. The obtained compressive residual stress σ _bCr is larger (| σ _bCr |> | σ _bCo |). This means that the compressive residual stress in the shallow interior of the substrate is greater than the compressive residual stress in the deep interior of the substrate. When σ _bCr is larger than σ _bCo (| σ _bCr |> | σ _bCo |), the adhesion between the coating and the substrate is improved. Conversely, when σ _bCr is _{equal to} or less than σ _bCo (| σ _bCr | ≦ | σ _bCo |), the adhesion between the coating film and the substrate decreases. In addition, although compressive residual stress (sigma) _bCu using the Cu-K (alpha) ray was measured about the base material of this invention, (sigma) _bCu did not have big influence on the adhesiveness of a film and a base material.

The residual stress of the WC-based cemented carbide base material can be obtained by measuring the residual stress of WC which is the main component. The residual stress of the cBN sintered compact substrate can be obtained by measuring the residual stress of cBN which is the main component. The residual stress of the Si ₃ N ₄ based ceramic substrate can be obtained by measuring the residual stress of Si ₃ N _{4 as} the main component. For cubic films such as TiAlN films, TiSiN films, CrAlN films, etc. whose physical properties (Poisson's ratio, Young's modulus, etc.) are not known, the physical properties of cubic TiN (Poisson's ratio, Young's modulus, etc.) Substituted.

As a method for imparting compressive residual stress to the base material of the present invention, glass beads having an average particle size of 50 to 200 μm are projected on the base material surface for 30 to 60 seconds on the base material surface before coating using a shot blasting device. The method of providing compressive residual stress can be mentioned.

As another method for imparting compressive residual stress to the substrate of the present invention, the substrate bias voltage is set to 0.6 kV in an inert gas atmosphere such as Ar, Kr, and Xe with respect to the substrate before coating using a PVD apparatus. Examples of the high energy pulse ion bombardment treatment described above can be given. The ion bombardment treatment in which ions such as inert gas and metal collide with the surface of the substrate has an effect of removing foreign substances on the surface of the substrate. In addition to the effect of cleaning the substrate surface, the ion bombardment treatment has an effect of applying compressive residual stress in the vicinity of the surface of the substrate. In the conventional method of using a DC potential for the substrate bias voltage, the substrate bias voltage is lowered to the minus side (by increasing the absolute value of the substrate bias voltage) to increase the compressive residual stress near the surface of the substrate. However, since the compressive residual stress is relieved by the annealing effect due to the temperature rise of the base material, a large compressive residual stress cannot be applied in the vicinity of the surface of the base material. However, when the pulse ion bombardment process using the pulse potential as the substrate bias voltage is performed as in the present invention, the substrate bias voltage is reduced to the minus side (even if the absolute value of the substrate bias voltage is increased). Since the temperature rise of the base material can be suppressed, a large compressive residual stress can be applied in the vicinity of the surface of the base material.

The coating of the present invention is a compound layer composed of at least one of the periodic table 4a, 5a, and 6a group elements, Al, Si, Y, and B and at least one of C, N, and O. The coating of the present invention improves wear resistance. Specifically, the coating of the present invention includes TiN, TiC, TiCN, (Ti, Al) N, (Cr, Al, Si) N, (Cr, Al) N, (Al, Zr) N, (Ti, Al , Si) N, (Ti, Cr, Al, Si) N, and the like. The film of the present invention may be either a single-layer film consisting of one layer or a multilayer film consisting of two or more layers. Among the multilayer films, one or more thin films having different compositions and having a thickness of 1 to 100 nm are alternately laminated. It may be a membrane.

The residual stress of the coating of the present invention was measured using Cr-Kα, Co-Kα, and Cu-Kα rays, and the compressive residual stress σ of the coating obtained by X-ray stress measurement using Cr-Kα rays _cCr, Co-Kα ray X-ray stress measurement by the resultant substrate compressive residual stress sigma _CCO using, Cu-K [alpha line X-ray stress measurement by the resultant of the base compressive residual stress sigma _CCU of using when the greatest compressive residual stress was sigma _bmax a medium, when the residual stress sigma _Bcr of the base material of the present invention, sigma _BCO, the smallest compressive residual stress in a sigma _BCU was sigma _cmin, sigma _bmax is sigma _cmin Is smaller than (| σ _bmax | <| σ _cmin |), because the adhesion between the coating and the substrate is further excellent. Among them, it is _preferable that σ _cCu is smaller than σ _cCo (| σ _cCu | <| σ _cCo |) because the adhesion between the coating and the substrate is further excellent.

As a method for producing the coating film of the present invention, a substrate is put in a commercially available arc ion plating apparatus (hereinafter referred to as AIP apparatus), and the surface of the substrate is subjected to ion bombardment treatment. To 923 K, acetylene (C ₂ H ₂ ), methane (CH ₄ ), nitrogen, oxygen or a mixed gas thereof is introduced as a reaction gas, and the arc discharge is performed with the pressure in the AIP apparatus set to 1 to 6 Pa. An example is a method in which an arc current is set to 100 to 150 A, a base material bias voltage (DC potential) is set to −80 to −180 V, and the base material surface is coated with a film. In order to make the residual stress distribution of the coating a desired value, the substrate bias voltage may be gradually lowered to the minus side from the start of coating.

The covering member of the present invention is excellent in wear resistance, chipping resistance and adhesion resistance. When the covering member of the present invention is used as a cutting tool, an effect that the tool life is extended is obtained. In particular, it is highly effective in cutting with severe processing conditions such as high-speed machining, high-feed machining, and machining of a hard material.

As a base material, a JIS standard SDKN1203AETN-shaped K20 equivalent WC-based cemented carbide insert was prepared. For Inventions 1, 2, and 5, glass beads having an average particle diameter of 100 μm were projected on the surface of the base material before coating for 30 to 60 seconds as shown in Table 1 using a shot blasting apparatus.

The base materials of invention products 1, 2, and 5 subjected to shot blast treatment and base materials of untreated invention products 3 and 4 and comparative products 1 to 6 were washed with acetone. The substrate after acetone cleaning was placed in an AIP apparatus, and bombardment treatment shown in Table 2 was performed. At this time, Invention 3 is subjected to Ar pulse ion bombardment treatment with a substrate bias voltage of 1 kV. Invention product 4 performs Kr pulse ion bombardment treatment with a substrate bias voltage of 1 kV. Conventional Ar ion bombardment treatment using a direct current potential is performed on the base materials other than the invention products 3 and 4. After performing these bombardment treatments, the temperature inside the AIP apparatus was raised by a heater until the temperature in the AIP apparatus reached 873 K, and the first layer and then the second layer were coated from the substrate side under the conditions shown in Table 2. The arrow of the substrate bias voltage indicates that the coating of the film starts from the voltage on the left side of the arrow, and the substrate bias voltage is gradually adjusted so as to become the voltage on the right side of the arrow at the end of the coating.

About the film thickness of the film coat | covered on the surface of the base material, each sample was cut | disconnected, the cross section was mirror-finished, and the obtained specular cross section was observed and measured with the optical microscope or the scanning electron microscope. About the composition of the film, a mirror-like cross section was measured using EPMA attached to a scanning electron microscope. These results are shown in Table 3.

[Residual stress measurement]
The residual stress of WC, which is the main component of the WC-based cemented carbide base material, was measured using a PSPC micro-part stress measuring device manufactured by Rigaku Corporation.

[Measurement condition]
(1) Measuring device: PSPC micro-part stress measuring device manufactured by Rigaku Corporation (2) X-ray source: Cu, Co, Cr
(3) X-ray output: voltage 30 kV, current 20 mA
(4) Collimator: φ2mm
(5) Incident angle: 0 °, 17 °, 24 °, 30 °, 35 °, 40 °

For the WC-based cemented carbide substrate, if the X-ray source is Cu, the WC (211) plane is measured, so the measurement angle is 2θ: 117.3 °. If the X-ray source is Co, WC ( 112) The measurement angle 2θ is 123.5 ° for measuring the plane, and if the X-ray source is Cr, the measurement angle 2θ is 135.7 ° for measurement on the WC (102) plane. The stress constant was calculated from the physical property values of WC, and the values are shown in Table 4.

The residual stress of the coating was measured using a PSPC micro-part stress measuring device manufactured by Rigaku Corporation.

[Measurement condition]
(1) Measuring device: PSPC micro-part stress measuring device manufactured by Rigaku Corporation (2) X-ray source: Cu, Co, Cr
(3) X-ray output: voltage 30 kV, current 30 mA
(4) Collimator: φ2mm
(5) Incident angle: 0 °, 17 °, 24 °, 30 °, 35 °, 40 °

With respect to the coating, if the X-ray source is Cu, the angle at which the diffraction line intensity is highest among 2θ: 131 to 151 ° is set as the measurement angle 2θ in order to measure the coating (511) plane, and the X-ray source is Co Then, in order to measure the coating (331) plane, the angle at which the diffraction line intensity is highest in 2θ: 123 to 143 ° is the measurement angle 2θ, and if the X-ray source is Cr, the coating (222) plane In order to perform measurement, the angle at which the diffraction line intensity is highest among the measurement angles 2θ: 128 to 148 ° is defined as the measurement angle 2θ. Since there is no existing physical property data for coatings other than the TiN film, the physical property value of TiN was used instead. The stress constant was calculated from the physical property values of TiN, and the values are shown in Table 5.

Table 6 shows the residual stress of the base material and the residual stress of the coating obtained from the above stress constants and measured values (Ψ, 2θ).

[Adhesion evaluation test]
An indentation method in which a Rockwell indenter (diamond indenter with a radius of curvature of 0.2 mm at the tip) is pushed into the sample surface to examine the peeled state of the coating, and a scratch test method using a scratch tester manufactured by CSM Instruments (a radius of curvature at the tip of 0.2 mm) The adhesion between the coating and the substrate was evaluated.

As shown in Table 7, in the indentation method using the Rockwell indenter, peeling of the film is not seen in the inventive product, but peeling of the coating is seen in the comparative product. In the scratch test, the load at which the inventive film peels is 140 N or more, but the load at which the comparative film peels is 80 N or less. From the above results, it can be seen that the inventive product has better adhesion between the coating and the substrate than the comparative product.

[Cutting test]
Using the coated cemented carbide tools of the inventive products 1 to 5 and the comparative products 1 to 6, the work material: Daikin Special Steel Co., Ltd. plastic mold steel NAK80, cutting speed: 150 m / min, cutting depth: 2. A dry milling test was performed under the conditions of 0 mm, feed: 0.15 mm / tooth. The tool life was estimated based on the flank wear amount VB = 0.30 mm. When the flank wear amount VB did not reach 0.3 mm by the cutting length 6 m, the flank wear amount VB at the cutting length 6 m was measured. These results are shown in Table 8.

As shown in Table 8, the inventive products 1 to 5 are not damaged even when the cutting length is 6 m, the flank wear amount VB is 0.18 mm or less, and have excellent wear resistance and fracture resistance. Have. On the other hand, the comparative products 1, 2, 5 and 6 have a flank wear amount VB of 0.24 mm or more at a cutting length of 6 m. Moreover, the comparative products 3 and 4 had a defect at the cutting length of 6 m.

As a base material, an insert made of cBN sintered body having a JIS standard CNGA120408 shape was prepared. For Invention Products 6 and 7, glass beads having an average particle size of 100 μm were projected on the surface of the base material before coating by a shot blasting device as shown in Table 9 for 45 to 60 seconds.

The base materials of the invention products 6 and 7 subjected to the shot blast treatment and the base materials of the untreated invention product 8 and the comparative products 7 and 8 were washed with acetone. The substrate after acetone cleaning was placed in an AIP apparatus, and bombardment treatment shown in Table 10 was performed. At this time, Invention Product 8 is subjected to Ar pulse ion bombardment treatment with a substrate bias voltage of 1 kV. For base materials other than the invention product 8, conventional Ar ion bombardment treatment using a DC potential is performed. After performing these bombardment treatments, the temperature inside the AIP apparatus was raised by a heater until the temperature in the AIP apparatus reached 873 K, and the first layer and then the second layer were coated from the substrate side under the conditions shown in Table 10. The arrow of the substrate bias voltage indicates that the coating of the film starts from the voltage on the left side of the arrow, and the substrate bias voltage is gradually adjusted so as to become the voltage on the right side of the arrow at the end of the coating.

About the film thickness of the film coat | covered on the surface of the base material, each sample was cut | disconnected, the cross section was mirror-finished, and the obtained specular cross section was observed and measured with the optical microscope or the scanning electron microscope. About the composition of the film, a mirror-like cross section was measured using EPMA attached to a scanning electron microscope. These results are shown in Table 11.

[Residual stress measurement]
The residual stress of cBN, which is the main component of the cBN sintered compact substrate, was measured using a PSPC micro-part stress measuring device manufactured by Rigaku Corporation.

[Measurement condition]
(1) Measuring device: PSPC micro-part stress measuring device manufactured by Rigaku Corporation (2) X-ray source: Cu, Co, Cr
(3) X-ray output: voltage 40 kV, current 30 mA
(4) Collimator: φ2mm
(5) Incident angle: 0 °, 17 °, 24 °, 30 °, 35 °, 40 °

For the cBN sintered compact substrate, if the X-ray source is Cu, the cBN (331) plane is measured, so the measurement angle is 2θ: 136.4 °, and if the X-ray source is Co, cBN (311 ) To measure the surface, the measurement angle 2θ was 110.3 °, and when the X-ray source was Cr, the measurement angle 2θ was 127.1 ° to measure on the cBN (220) surface. The stress constant was calculated from the physical property values of cBN, and the values are shown in Table 12.

The residual stress of the film was measured under the same conditions as in Example 1 using a PSPC micro-part stress measuring device manufactured by Rigaku Corporation. Table 13 shows the residual stress of the base material and the residual stress of the coating film determined from the above stress constants and measured values (Ψ, 2θ).

[Adhesion evaluation test]
An indentation method in which a Rockwell indenter (diamond indenter with a radius of curvature of 0.2 mm at the tip) is pushed into the sample surface to examine the peeled state of the coating, and a scratch test method using a scratch tester manufactured by CSM Instruments (a radius of curvature at the tip of 0.2 mm) The adhesion between the coating and the substrate was evaluated.

As shown in Table 14, in the indentation method using the Rockwell indenter, the peel-off of the film is not seen in the inventive product, but the peel-off of the film is seen in the comparative product. In the scratch test, the load at which the inventive film peels is 110 N or more, but the load at which the comparative film peels is 80 N or less. From the above results, it can be seen that the inventive product has better adhesion between the coating and the substrate than the comparative product.

[Cutting test]
Using the coated cBN sintered body tools of invention products 6 to 8 and comparative products 7 and 8, work material: SCM415H (carburized product), cutting speed: 250 m / min, cutting: 0.25 mm, feed: 0. A dry continuous turning test of up to 20 minutes was performed under the condition of 10 mm / rev. The tool life was defined as the tool life when the crater wear on the rake face reached the cutting edge. Table 15 shows the tool life and the damage state of the invention and comparative products.

As shown in Table 15, the invention products 6 and 8 are normally worn up to a cutting time of 20 minutes, the invention product 7 is normally worn up to a cutting time of 15 minutes, and the comparative product is peeled off at a cutting time of 10 minutes or less Was

As a base material, a JIS standard CNMA120408-shaped Si ₃ N ₄ ceramic insert was prepared and washed with acetone. The substrate after acetone cleaning was placed in an AIP apparatus, and bombardment treatment shown in Table 16 was performed. At this time, Invention Product 9 is subjected to Kr pulse ion bombardment treatment with a substrate bias voltage of 1 kV. Invention product 10 is subjected to Ar pulse ion bombardment treatment with a substrate bias voltage of 1.2 kV. Invention product 10 is subjected to Kr pulse ion bombardment treatment with a substrate bias voltage of 1.5 kV. The base materials of comparative products 9 and 10 are subjected to conventional Ar ion bombardment treatment using a direct current potential. After performing these bombardment treatments, the temperature inside the AIP apparatus was raised by a heater until the temperature in the AIP apparatus reached 873 K, and the first layer and then the second layer were coated from the substrate side under the conditions shown in Table 16. Comparative products 9 and 10 are coated with a film using a pulse potential as a substrate bias voltage, and Invention products 9 to 11 are coated with a film using a DC potential as a substrate bias voltage. The arrow of the substrate bias voltage indicates that the coating of the coating starts from the voltage on the left side of the arrow, and the substrate bias voltage is gradually adjusted so as to become the voltage on the right side of the arrow at the end of coating.

About the film thickness of the film coat | covered on the surface of the base material, each sample was cut | disconnected, the cross section was mirror-finished, and the obtained specular cross section was observed and measured with the optical microscope or the scanning electron microscope. About the composition of the film, a mirror-like cross section was measured using EPMA attached to a scanning electron microscope. These results are shown in Table 17.

[Residual stress measurement]
Using Rigaku PSPC miniature unit stress measuring device was measured residual stress the Si ₃ N ₄ as the main component the Si ₃ N ₄ based ceramic substrate.

[Measurement condition]
(1) Measuring device: PSPC micro-part stress measuring device manufactured by Rigaku Corporation (2) X-ray source: Cu, Co, Cr
(3) X-ray output: voltage 40 kV, current 30 mA
(4) Collimator: φ2mm
(5) Incident angle: 0 °, 17 °, 24 °, 30 °, 35 °, 40 °

For the cBN sintered body substrate, if the X-ray source is Cu, the measurement angle 2θ is 117.0 ° in order to measure the Si ₃ N ₄ (441) plane, and if the X-ray source is Co, In order to measure the Si ₃ N ₄ (611) plane, the measurement angle 2θ is 140.9 °. When the X-ray source is Cr, the measurement angle 2θ is 131 to measure on the Si ₃ N ₄ (212) plane. .5 °. The stress constant was calculated from the physical property values of cBN, and the values are shown in Table 18.

The residual stress of the film was measured under the same conditions as in Example 1 using a PSPC micro-part stress measuring device manufactured by Rigaku Corporation. Table 19 shows the residual stress of the base material and the residual stress of the coating film determined from the above stress constants and measured values (Ψ, 2θ).

[Adhesion evaluation test]
An indentation method in which a Rockwell indenter (diamond indenter with a radius of curvature of 0.2 mm at the tip) is pushed into the sample surface to examine the peeled state of the coating, and a scratch test method using a scratch tester manufactured by CSM Instruments (a radius of curvature at the tip of 0.2 mm) The adhesion between the coating and the substrate was evaluated.

As shown in Table 20, in the indentation method using the Rockwell indenter, peeling of the film is not seen in the inventive product, but peeling of the coating is seen in the comparative product. In the scratch test, the load at which the inventive film peels is 110 N or more, but the load at which the comparative film peels is 75 N or less. From the above results, it can be seen that the inventive product has better adhesion between the coating and the substrate than the comparative product.

[Cutting test]
Using the coated Si ₃ N ₄ ceramic tools of Inventions 9 to 11 and Comparative Products 9 and 10, work material: FCD250 (with black skin), cutting speed: 800 m / min, cutting: 1.5-2. A dry continuous turning test up to a cutting length of 2000 m was performed under the conditions of 0 mm, feed: 0.60 mm / rev. The tool life was estimated based on the flank wear amount VB = 0.50 mm. The results of the cutting test are shown in Table 21.

As shown in Table 21, invention products 9 to 11 have a flank wear amount VB at a cutting length of 2000 m of 0.36 mm or less and can be cut, but comparative products 9 and 10 have a flank wear amount VB at a cutting length of 2000 m. It was 0.60 mm or more, and was judged to be a lifetime.

Claims (2)

The compressive residual stress σ _bCr of the base material obtained by X-ray stress measurement using a Cr—Kα ray _consisting of a base material and a film coated on the surface thereof is measured by X-ray stress using Co—Kα ray. A coated tool larger than the compressive residual stress σ _bCo of the base material obtained by Cr-K [alpha line X-ray stress compressive residual stress sigma _Bcr obtained substrate by the measurements, compressive residual stress of the base material obtained by the X-ray stress measurement using Co-K [alpha line sigma _BCO and Cu- The largest compressive residual stress σ _bmax of the base material among the compressive residual stress σ _bCu of the base material obtained by the X-ray stress measurement using the Kα ray is obtained by the X-ray stress measurement using the Cr—Kα ray. compressive residual stress sigma _cCr coating, compression coating obtained by X-ray stress measurement using the compressive residual stress sigma _CCO and Cu-K [alpha line resulting coating by X-ray stress measurement using Co-K [alpha line The coated tool according to claim 1, which is smaller than the compressive residual stress σ _cmin of the base material that is the smallest among the residual stress σ _cCu .