JP6602672B2 - Coated tool - Google Patents

Description

  The present invention relates to a coated tool.

  Coated tools are widely used for cutting of steel, cast iron, stainless steel, heat-resistant alloys and the like. For example, a coated tool in which a TiN layer or a TiAlN layer is formed on the surface of a base material such as cemented carbide, cermet, or cBN sintered body is widely used.

  As a conventional technique of a coated tool, a coated tool described in Patent Document 1 is known. The coated tool described in Patent Document 1 includes a substrate including hard particles and a binder phase, and a coating. Concavities and convexities are formed on the surface of the hard particles in contact with the coating. The surface roughness Rz of the rake face of the substrate is 1.0 μm or more and 30 μm or less.

  Moreover, the coating tool described in patent document 2 is known as a prior art of a coating tool. The coated tool described in Patent Document 2 includes a base material made of WC-base cemented carbide, cermet, ceramics, high-speed steel, and the like, and a coating formed on the surface of the base material. The coating contains a nitride, oxide, carbide, carbonitride, or boride of an alloy composed of a group IVa, Va, VIa group metal element and two or more elements selected from Al and Si. The coating is formed by physical vapor deposition so as to have a particle size of 50 nm or less.

JP 2012-157915 A Japanese Patent No. 3341328

  In the coated cutting tool disclosed in Patent Document 1, since hard particles protrude locally from the surface of the substrate, when cutting is performed with high-speed machining and high-efficiency machining, There was a problem that peeling occurred.

  The coated tool disclosed in Patent Document 2 includes a coating composed of fine particles, and when the cutting edge of the coated tool and the work material are abraded during cutting, the particles constituting the coating fall off. For this reason, the coated tool disclosed in Patent Document 2 has a problem of poor wear resistance.

  In recent years, the speeding up and efficiency of cutting have become remarkable, and since the load is applied to the coated tool more than before, the tool life tends to be reduced.

  The present invention has been made to solve such a problem, and an object thereof is to provide a long-life coated tool having excellent wear resistance, peeling resistance and fracture resistance.

  The present inventor has studied the extension of the life of the coated tool from the above viewpoint and completed the present invention. ADVANTAGE OF THE INVENTION According to this invention, the long-life coated tool which has the outstanding abrasion resistance, peeling resistance, and chipping resistance can be provided.

The gist of the present invention is as follows.
[1] A coated tool comprising a substrate and a coating layer formed on the surface of the substrate,
The substrate includes a plurality of hard particles and a binder phase that binds the plurality of hard particles,
The coating layer includes one or more compound layers,
The compound layer includes at least one metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Al, and Si, and C, N, O, and B. A layer of a compound comprising at least one nonmetallic element selected from the group consisting of:
The coated tool whose B / A value calculated | required by the following procedures (1)-(6) is 0.2-0.5.
(1) A cross section perpendicular to the surface of the substrate is extracted by a reference length S in a direction parallel to the surface of the substrate.
(2) In the extracted cross section, the total area A of the cross section of the hard particles in contact with the coating layer is obtained.
(3) At the boundary surface between the coating layer and the base material, the first boundary portion D1 at the deepest position among the plurality of boundary portions formed between the hard particles adjacent to each other, and 2 The second boundary portion D2 at the deepest position is determined.
(4) A line segment L passing through the first boundary portion D1 and the second boundary portion D2 is drawn.
(5) The total area B of the cross section which exists in the coating layer side rather than the said line segment L among the cross sections of the said hard particle which is in contact with the said coating layer is calculated | required.
(6) The value of B / A is obtained.

[2] The coated tool according to [1], wherein the reference length S is at least five times the average particle size of the hard particles.

[3] The coating layer includes a plurality of particles,
The particle size d50 when the cumulative frequency based on the number of the plurality of particles contained in the coating layer is 50% is 0.1 μm or more and 0.2 μm or less,
The coated tool according to [1] or [2], wherein the particle size d80 when the cumulative frequency based on the number of the plurality of particles contained in the coating layer is 80% is 0.25 μm or more and 0.45 μm or less.

[4] The coated tool according to any one of [1] to [3], wherein an average thickness of the coating layer is 0.6 μm or more and 15 μm or less.

[5] The coated tool according to any one of [1] to [4], wherein the hard particles included in the base material have an average particle diameter of 0.3 μm or more and 5 μm or less.

  The hard particles contained in the base material are at least one metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, and C, N, O and B The coated tool according to any one of [1] to [5], which is a particle of a compound containing at least one nonmetallic element selected from the group consisting of:

The figure for demonstrating the total area A of the cross section of the hard particle which touches a coating layer, and the total area B of the cross section of the hard particle from the line segment L to the coating layer side. The figure for demonstrating the total area A of the cross section of the hard particle which touches a coating layer, and the total area B of the cross section of the hard particle from the line segment L to the coating layer side. The figure for demonstrating the total area A of the cross section of the hard particle which touches a coating layer, and the total area B of the cross section of the hard particle from the line segment L to the coating layer side. The schematic diagram of a cross section perpendicular | vertical to the surface of a base material. The schematic diagram of a cross section perpendicular | vertical to the surface of a base material. The schematic diagram of a cross section perpendicular | vertical to the surface of a base material.

<Coated tool>
The coated tool of the present invention includes a substrate and a coating layer formed on the surface of the substrate. The coated tool is, for example, a milling insert or a turning insert, a drill, or an end mill.

<Base material>
The base material of the present invention is not particularly limited as long as it is used as a base material for a coated tool. Specific examples of the substrate include cemented carbide and cermet. Among these, it is preferable that the base material is a cemented carbide excellent in wear resistance and fracture resistance.

  The base material of the present invention includes hard particles and a binder phase that binds the hard particles. The hard particles are selected from the group consisting of at least one metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, and C, N, O and B It is a compound composed of at least one nonmetallic element.

<Particle size of hard particles>
The particle diameter of the hard particles of the present invention is defined as the diameter (equivalent circle diameter) of a circle having an area equal to the area of the cross section of the hard particles in a cross section perpendicular to the surface of the substrate.

<Average particle size of hard particles>
The average particle size of the hard particles of the present invention is defined as a value obtained by dividing the sum of the particle sizes of a plurality of hard particles by the number of the hard particles.
The average particle size of the hard particles is, for example, the sum of the particle sizes of the hard particles existing in the cross section when the photograph of the cross section perpendicular to the surface of the substrate is viewed. It can be determined by dividing by a number. At this time, the number of hard particles present in the cross section is preferably 5 or more, and more preferably 10 or more.

  When the average particle size of the hard particles is less than 0.3 μm, the fracture resistance of the tool tends to be reduced. When the average particle size of the hard particles exceeds 5 μm, the wear resistance of the tool tends to decrease. Therefore, the average particle diameter of the hard particles is preferably 0.3 μm or more and 5 μm or less.

FIG. 1 shows an example of a cross-sectional polished surface perpendicular to the surface of the substrate.
As shown in FIG. 1, a coating layer is formed on the surface of the substrate. The substrate includes a plurality of hard particles and a binder phase that binds the plurality of hard particles. Some of the plurality of hard particles contained in the substrate are in contact with the coating layer. A plurality of boundary portions are formed between the hard particles adjacent to each other on the boundary surface between the coating layer and the substrate.

  FIG. 2 is a schematic view of a cross section perpendicular to the surface of the substrate. Hereinafter, with reference to FIG. 1 and FIG. 2, a method for obtaining the B / A value, which is a feature of the coated tool of the present invention, will be described.

(1) First, a vertical section on the surface of the substrate is extracted by a reference length S in a direction parallel to the surface of the substrate. The reference length S is preferably at least 5 times the average particle size of the hard particles.

(2) Next, in the cross section extracted by the reference length S, the total area A of the cross section of the hard particles in contact with the coating layer is obtained. The total area A of the cross section of the hard particles can be determined by, for example, commercially available image processing software.

(3) The first boundary portion D1 at the deepest position among the plurality of boundary portions formed between adjacent hard particles at the boundary surface between the coating layer and the base material, and the second deepest The second boundary portion D2 at the position is determined. “Deep” here means, for example, the lower side of FIG. 2 and means the direction from the coating layer toward the substrate. The first boundary part D1 and the second boundary part D2 may be located at the same depth.

(4) A line segment L passing through the first boundary portion D1 and the second boundary portion D2 is drawn.

(5) In the cross section extracted by the reference length S, the total area B of the cross section above the line segment L among the cross sections of the hard particles in contact with the coating layer is obtained. The total area B of the cross section above the line segment L can be obtained by, for example, commercially available image processing software.

(6) The value of B / A is obtained.

  B / A is 0.2 or more and less than 0.5. When B / A is less than 0.2, the anchor effect between the base material and the coating layer is lowered, so that the adhesion between the base material and the coating layer is lowered. When B / A is 0.5 or more, since the area of the convex portion of the hard particle is large, abnormal damage may occur in the coated tool.

  In the present invention, the reference length S is preferably at least 5 times the average particle size of the hard particles. When the reference length S is less than 5 times the average particle diameter of the hard particles, the number of hard particles included in the range of the reference length S is small, so that the measurement error increases.

  The coated tool of the present invention is characterized in that the value of B / A is 0.2 or more and less than 0.5. It is not necessary that the B / A value is 0.2 or more and less than 0.5 on the entire surface of the tool. . For example, in the cross section of the screw hole for attaching the insert, the value of B / A does not have to be 0.2 or more and less than 0.5. This is because the screw hole is not a part involved in cutting. Specifically, it is preferable that the value of B / A is 0.2 or more and less than 0.5 in a cross section of 60% or more of a part involved in cutting. More preferably, the B / A value is 0.2 or more and less than 0.5 in a cross section of 70% or more, and more preferably, the B / A value is 0.2 or more and 0.5 in a cross section of 80% or more. Is less than. When the B / A value is 0.2 or more and less than 0.5 in a cross section of 80% or more of the part involved in cutting, very good cutting performance can be obtained.

  For example, when 5 cross-sections are inspected, when the above relationship is satisfied in 4 cross-sections (4 visual fields out of 5 fields), it can be said that the above relationship is satisfied in 80% of cross-sections. It is preferable that the number of cross sections to be inspected is large, but if at least 5 cross sections are inspected, a predetermined correlation between the value of B / A and the cutting performance can be obtained.

<Coating layer>
The coating layer of the present invention includes one or more compound layers. The compound layer includes at least one metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Y, Al, and Si, and C, N, O, and B. It is a layer of a compound containing at least one nonmetallic element selected from the group consisting of: Such a compound layer is preferable because of its excellent wear resistance. More preferably, the compound layer has a structure in which a plurality of layers having different compositions are alternately laminated.

  The average thickness of the entire coating layer of the present invention is preferably 0.6 μm or more and 15 μm or less. When the average thickness of the entire coating layer is less than 0.6 μm, the wear resistance tends to decrease. When the average thickness of the entire coating layer exceeds 15 μm, the chipping resistance tends to decrease.

  The thickness of the coating layer is observed by using an optical microscope, a scanning electron microscope (SEM), a field emission scanning electron microscope (FE-SEM), a transmission electron microscope (TEM), etc. Can be measured.

  In addition, the thickness of each layer of a coating layer can be measured in the vicinity of the position of 50 micrometers toward the center part of a coating tool from the blade edge of the surface facing a metal evaporation source. The thickness of each layer of the coating layer can be measured at three or more locations in each layer. Thickness average values measured at three or more locations of each layer can be used as representative values of the thickness of each layer.

  The composition of each layer can be measured using an energy dispersive X-ray spectrometer (EDS) attached to an electron microscope such as SEM, FE-SEM, or TEM, or a wavelength dispersive X-ray spectrometer (WDS). .

<Particle size of particles contained in coating layer>
The coating layer of the present invention has a crystal structure and includes a plurality of particles (crystal particles). The particle size of the particles contained in the coating layer can be measured by the following procedure.
First, a cross section perpendicular to the surface of the substrate is polished. The polished cross-sectional structure is observed using an electron microscope or the like.
Next, in the observed cross section, a line segment parallel to the surface of the substrate is drawn so as to cross a plurality of particles contained in the coating layer. At this time, the length of the line segment cut by the grain boundary is the particle size of the particle. In other words, the length of the line segment cut by the outer edge of each particle is defined as the particle size of the particle.

  The particle size of the particles traversed by the line segment is measured. From the measurement result of the particle size, a graph of the cumulative frequency of particles contained in the coating layer can be created. In this graph, the horizontal axis represents the particle size (μm), and the vertical axis represents the number-based cumulative frequency (%). The total number of particles traversed by the line segment corresponds to a cumulative frequency of 100%. From this graph, it is possible to know how much of particles that are less than a certain particle size (or more than a certain particle size) occupy on a number basis among all particles that are crossed by a line segment.

  The particle diameter d50 at which the cumulative frequency based on the number of particles contained in the coating layer is 50% is preferably 0.1 μm or more and 0.2 μm or less. The particle diameter d80 at which the cumulative frequency based on the number of particles contained in the coating layer is 80% is preferably 0.25 μm or more and 0.45 μm or less. When the particle diameter d50 at which the cumulative frequency of particles is 50% is less than 0.1 μm, there are many fine particles, and thus the wear resistance of the coating layer tends to be reduced. When the particle diameter d50 at which the cumulative frequency of particles is 50% exceeds 0.2 μm, the peel resistance of the coating layer tends to be reduced. When the particle diameter d80 at which the cumulative frequency of particles is 80% is less than 0.25 μm, the coating layer has a uniform and fine structure, and thus the wear resistance of the coating layer tends to be reduced. When the particle diameter d80 at which the cumulative frequency of particles is 80% exceeds 0.45 μm, the peel resistance and fracture resistance of the coating layer tend to decrease.

In order to obtain the particle size of the particles of the coating layer, the section of the coated tool is mirror-polished and the structure of the polished section is observed. This cross section is perpendicular to the surface of the substrate.
In order to determine the particle size of the particles of the coating layer, for example, a cross section near the surface of the coating layer may be observed, but a cross section near the interface between the coating layer and the substrate may be observed.

Examples of the method of mirror polishing the coating layer include a method of polishing using diamond paste or colloidal silica, ion milling, and the like.
The cross-section polished surface excluding droplets having a diameter of 100 nm or more can be observed using an electron beam backscatter diffraction (EBSD) method using FE-SEM or the like. Observation is performed for each field of view by selecting a plurality of fields of view on the polished surface. The particles of the coating layer existing in each visual field are color-coded (mapped) for each crystal orientation so that the particles of the coating layer can be visually confirmed. Take a mapped image. A straight line parallel to the surface of the substrate having a predetermined length is drawn on the coating layer of the photographed mapping image, and the particle diameter of each particle traversed by the straight line is measured.
In addition, on the cross-section polished surface of the coating layer, a droplet having a diameter of 100 nm or more and a cross-sectional structure other than the droplet can be easily distinguished. When the cross-section polished surface is observed, voids having a thickness of several nanometers to several tens of nanometers are formed around the droplets. Therefore, in the coating layer, a droplet having a diameter of 100 nm or more and a cross-sectional polished surface other than the droplet can be easily distinguished.

  In order to determine the particle size of the hard particles contained in the substrate, the cross-section polished surface of the coated tool is observed. Specifically, an arbitrary cross section of the coated tool is mirror-polished, and the structure of the polished cross section is observed.

Examples of the method of mirror polishing the substrate include a method of polishing using diamond paste or colloidal silica, ion milling, and the like.
The cross-section polished surface can be observed using an EBSD method such as FE-SEM. Observation is performed for each field of view by selecting a plurality of fields of view on the polished surface. The hard particles of the substrate existing in each visual field are color-coded (mapped) for each crystal orientation so that the hard particles of the substrate can be visually confirmed. Take a mapped image. Next, the photographed mapping image is analyzed using commercially available image analysis software. From this analysis result, the diameter of a circle having an area equal to the area of the cross section of the hard particles contained in the substrate is obtained. This diameter is calculated | required as a particle size of the hard particle | grains of a base material. The particle diameters of all hard particles present in the photographed mapping image are obtained. The average value of these particle sizes is determined.

  In order to obtain the total area A of the cross section of the hard particles in contact with the coating layer, the cross-section polished surface of the coated tool is observed. In order to obtain the total area B of the cross section above the line segment L, the cross-section polished surface of the coated tool is observed.

  Specifically, a value five times the average particle diameter of the hard particles of the base material is obtained, and this value is determined as the reference length S. Using a FE-SEM or the like, a reflected electron image of the cross-section polished surface near the interface between the base material and the coating layer is taken. A reflected electron image of the photographed cross-section polished surface is extracted by a reference length S in a direction parallel to the surface of the substrate. The captured backscattered electron image is analyzed using commercially available image analysis software. From this analysis result, the total area A of the cross section of the hard particles in contact with the coating layer is obtained (see FIG. 1B). Next, a plurality of boundary portions formed by the hard particles adjacent to each other are determined on the boundary surface between the coating layer and the substrate. Among the plurality of boundary portions, the first boundary portion D1 at the deepest position and the second boundary portion D2 at the second deepest position are determined. A line segment L passing through the first boundary portion D1 and the second boundary portion D2 is drawn (see FIG. 1A). Using a commercially available image analysis software, among the cross sections of the hard particles in contact with the coating layer, the total area B of the cross section on the coating layer side (upward) from the line segment L is obtained (see FIG. 1C). . From the total area A and the total area B determined as described above, the value of B / A can be calculated.

  The particle diameter of the particles of the coating layer and the particle diameter of the hard particles of the substrate can be measured using, for example, EBSD. EBSD can be preferably used because the grain boundaries of the particles can be clearly observed. The EBSD is preferably set so that a boundary having a step size of 0.01 μm, a measurement range of 2 μm × 2 μm, and an orientation difference of 5 ° or more is regarded as a grain boundary.

  Next, the manufacturing method of the coated tool of this invention is demonstrated using a specific example. In addition, the manufacturing method of the coated tool of this invention is not restrict | limited especially as long as the structure of the said coated tool can be achieved.

  For example, in the method for manufacturing a coated tool of the present invention, a tool-shaped base material including hard particles and a binder phase that binds the hard particles is prepared. Subsequently, honing is performed on the base material using a brush or the like. The surface of the substrate may be a sintered skin surface, but is preferably a ground surface subjected to grinding. When the surface of a base material is a grinding surface, the surface of a base material becomes smoother.

Next, as a first step, dry shot blasting is performed on the substrate with low projection energy. Thereby, irregularities are formed at the grain boundaries of the hard particles. For example, the dry shot blasting conditions are a projection angle of 30 to 90 ° with respect to the surface of the coating layer, a projection pressure of 0.02 to 0.05 MPa, and a treatment time of 2 to 5 minutes. The average particle size of the projection material for dry shot blasting is preferably 80 to 100 μm. The material of the projection material is preferably, for example, Al ₂ O ₃ or ZrO ₂ .

In the first step, dry shot blasting is performed on the substrate with low projection energy. After the first step, as a second step, dry shot blasting is performed on the substrate with high projection energy. Thereby, unevenness | corrugation can be formed in the surface of a hard particle. For example, the dry shot blasting conditions are a projection angle of 30 to 90 ° with respect to the surface of the coating layer, a projection pressure of 0.1 to 0.3 MPa, and a treatment time of 10 to 30 seconds. The processing time of the second step may be shorter than the processing time of the first step. The average particle size of the projection material for dry shot blasting is preferably 120 to 150 μm. The material of the projection material is preferably, for example, Al ₂ O ₃ or ZrO ₂ .

  Next, as a third step, a fragile layer generated on the substrate by dry shot blasting is removed by ion bombardment. By removing the fragile layer, the adhesion between the substrate and the coating layer can be improved.

The ion bombardment process is performed, for example, according to the following procedure.
A substrate is introduced into the reaction vessel.
The substrate is heated to a temperature of 200 to 800 ° C. with a heater in the reaction vessel.
After heating the substrate, Ar gas is introduced into the reaction vessel.
The inside of the reaction vessel is adjusted to an Ar gas atmosphere with a pressure of 3.0 Pa to 7.0 Pa.
Ion bombardment treatment is performed under the condition of a bias voltage of −300 V to −600 V applied to the substrate.

  After the ion bombardment treatment is performed on the substrate surface as described above, a coating layer can be formed on the substrate by physical vapor deposition. Examples of the physical vapor deposition method include an arc ion plating method, an ion plating method, a sputtering method, and an ion mixing method. Among these, the arc ion plating method is more preferable because of excellent adhesion between the base material and the coating layer.

  The coated tool of this invention can also be manufactured with the following method, for example.

  A base material is put in a reaction vessel of an arc ion plating apparatus. Nitrogen gas as a raw material for the coating layer is introduced into the reaction vessel. The atmosphere in the reaction vessel is a nitrogen atmosphere. Subsequently, the pressure in the reaction vessel is set to 2 to 5 Pa. The substrate is heated to a temperature of 400 to 800 ° C. with an in-furnace heater. A coating layer is formed on the surface of the base material under the conditions of a bias voltage of −150 to −50 V applied to the base material and an arc current of 100 to 180 A.

[The invention's effect]
The coated tool of the present invention is excellent in wear resistance, peel resistance and fracture resistance, and has an effect that the tool life is longer than that in the prior art.

  As a base material, an ISO standard SEKN1203AGTN insert-shaped cemented carbide equivalent to P20 was prepared. A dry shot blasting treatment was performed on the base materials of Invention Products 1 to 10 and Comparative Product 9 under the conditions shown in Table 1.

  Next, a metal evaporation source having a coating layer composition shown in Table 3 was placed in the reaction vessel of the arc ion plating apparatus. The prepared base material was fixed to the fixture of the turntable in the reaction vessel.

Then, it was evacuated until the pressure in the reaction vessel became a vacuum of 5.0 × 10 ⁻³ Pa or less. After evacuation, the substrate was heated with a heater in the reaction vessel until the temperature of the substrate reached 500 ° C. After heating, Ar gas was introduced into the reaction vessel so that the pressure in the reaction vessel was 5.0 Pa. Next, ion bombardment treatment was performed on the base material under the conditions shown in Table 2.

After the ion bombardment treatment, the inventive products 1, 3 to 10 and the comparative products 1 to 10 were evacuated until the pressure in the reaction vessel became a vacuum of 5.0 × 10 ⁻³ Pa or less. After evacuation, nitrogen gas was introduced into the reaction vessel to create a nitrogen gas atmosphere at a pressure of 2.7 Pa. A bias voltage of −50 V was applied to the substrate, and the metal evaporation source was evaporated by arc discharge with an arc current of 150 A to form a coating layer. After forming the coating layer, the heater was turned off, and the sample was taken out from the reaction vessel after the sample temperature became 100 ° C. or lower.

After the ion bombardment treatment, the invention 2 was evacuated until the pressure in the reaction vessel became a vacuum of 5.0 × 10 ⁻³ Pa or less. After evacuation, nitrogen gas and methane gas were introduced into the reaction vessel and mixed so that the partial pressure ratio of nitrogen gas and methane gas at a pressure of 2.7 Pa was nitrogen gas: methane gas = 1: 1. A bias voltage of −50 V was applied to the base material, and the metal evaporation source was evaporated by arc discharge with an arc current of 150 A to form a coating layer. After forming the coating layer, the heater was turned off, and the sample was taken out from the reaction vessel after the sample temperature became 100 ° C. or lower.

  The average thickness of each layer included in the coating layer of the obtained sample was measured using SEM. Specifically, the cross section of the sample facing the metal evaporation source was mirror-polished with diamond paste. The cross section of the polished sample was observed using SEM. In the cross section of the observed sample, the thickness of the coating layer was measured at five locations. The average value of the thickness of the coating layer measured in five places was calculated. The composition of the coating layer of the sample was measured in the reaction vessel of the arc ion plating apparatus used for manufacturing each sample. Specifically, the cross section of the sample facing the metal evaporation source was measured using EDS. These measurement results are shown in Table 3.

  After measuring the average thickness of the coating layer, the cross-section polished surface of the coated tool was observed by the EBSD method using FE-SEM, and the average particle size of the hard particles of the substrate was determined. The EBSD was set such that a boundary having a step size of 0.01 μm, a measurement range of 2 μm × 2 μm, and an orientation difference of 5 ° or more was regarded as a grain boundary. Next, a value five times the average particle size of the hard particles of the base material was determined, and this value was determined as the reference length S. Using a FE-SEM, a backscattered electron image of the cross-section polished surface at the interface between the base material and the coating layer in the range including the reference length S was taken. Using a commercially available image analysis software, the total area A and the total area B of the hard particles in contact with the coating layer were determined from the photographed reflected electron image. Table 4 shows the average particle size and B / A of the hard particles of the substrate.

  Then, the structure | tissue which remove | eliminated the droplet of diameter 100nm or more from the cross-section grinding | polishing surface of the coating layer was observed by the EBSD method by FE-SEM, and the particle size of the particle | grains of the coating layer was calculated | required. The EBSD was set such that a boundary having a step size of 0.01 μm, a measurement range of 2 μm × 2 μm, and an orientation difference of 5 ° or more was regarded as a grain boundary. The cumulative frequency of the number of particles in the coating layer with respect to the average particle size of the particles in the coating layer was determined when the total number of particles in the coating layer observed was 100%. Average particle diameters at which the cumulative frequency was 50% and 80% were determined. Table 5 shows the average particle diameter at which the cumulative frequency becomes 50% and 80%.

  From Tables 4 and 5, Inventions 1 to 10 are particles in which the B / A relating to the hard particles of the base material is in the range of 0.2 or more and less than 0.5, and the cumulative frequency of the particles of the coating layer is 50%. It can be seen that the diameter is in the range of 0.1 μm or more and 0.2 μm or less, and the particle diameter at which the cumulative frequency of particles in the coating layer is 80% is in the range of 0.25 μm or more and 0.45 μm or less.

  Using the obtained sample, face milling was performed under the following test conditions 1 and 2, and peeling resistance, wear resistance, and fracture resistance were evaluated.

[Test condition 1]
Work material: FCD600,
Work material shape: 50 mm × 200 mm × 150 mm rectangular parallelepiped (however, face milling is performed on a 105 mm × 200 mm surface),
Cutting speed: 150 m / min,
Feed: 0.2mm / tooth,
Cutting depth: 2.0 mm
Cutting width: 46 mm
Coolant: Not used (dry processing)
Effective cutter diameter: φ80mm,
Evaluation item: The peeled area when the processing length was 2.0 m was confirmed.

Table 6 shows the peeled area when the processing length in Test Condition 1 is 2.0 m.

  From Table 6, it was confirmed that the inventive product had a smaller peeled area of the coating layer than the comparative product. From the above results, it was confirmed that the inventive product is superior in peel resistance to the comparative product.

[Test condition 2]
Work material: S45C,
Work material shape: 105 mm × 200 mm × 60 mm cuboid (however, six holes with a diameter of 30 mm are drilled on the 105 mm × 200 mm surface of the cuboid to be face milled),
Cutting speed: 250 m / min,
Feed: 0.1 mm / tooth,
Cutting depth: 2.0 mm
Cutting width: 50 mm
Coolant: Not used (dry processing)
Effective cutter diameter: φ125mm,
Evaluation item: When the sample was missing or when the maximum flank wear width of the sample reached 0.2 mm, the tool life was measured, and the machining length up to the tool life was measured.

Table 7 shows the machining lengths up to the tool life under test condition 2.

  As shown in Table 7, it can be seen that the invention products have normal wear in all the samples, and the fracture resistance is superior to the comparative products. When the invention product is compared with a comparative product in which the damage form is normal wear, the processing length of the invention product is 5.1 m or more, and the processing length is longer than 4.0 m of the comparison product. From this result, it can be seen that the inventive product has a longer tool life than the comparative product.

  As a base material, an ISO standard SEKN1203AGTN insert-shaped cermet was prepared. Dry shot blasting was performed on the base materials of Invention Products 11 and 12 and Comparative Product 11 under the conditions shown in Table 8.

  Next, a metal evaporation source having a coating layer composition shown in Table 10 was placed in the reaction vessel of the arc ion plating apparatus. The prepared base material was fixed to the fixture of the turntable in the reaction vessel.

Then, it evacuated until the pressure in reaction container was set to the vacuum of 5.0 * 10 < ^-3 > Pa or less. After evacuation, the substrate was heated with a heater in the reaction vessel until the temperature of the substrate reached 500 ° C. After heating, Ar gas was introduced so that the pressure in the reaction vessel was 5.0 Pa. Next, ion bombardment treatment was performed on the base material under the conditions shown in Table 9.

The obtained sample was evacuated after the ion bombardment treatment until the pressure in the reaction vessel became a vacuum of 5.0 × 10 ⁻³ Pa or less. After evacuation, nitrogen gas was introduced into the reaction vessel to create a nitrogen gas atmosphere at a pressure of 2.7 Pa. A bias voltage of −50 V was applied to the substrate, and the metal evaporation source was evaporated by arc discharge with an arc current of 150 A to form a coating layer on the surface of the substrate. After forming the coating layer, the heater was turned off, and the sample was taken out from the reaction vessel after the sample temperature became 100 ° C. or lower.

  The average thickness of each layer included in the coating layer of the obtained sample was measured. Specifically, the cross section of the sample facing the metal evaporation source was mirror-polished with diamond paste. The polished cross section was observed using SEM. In the observed cross section, the thickness of the coating layer was measured at five locations. The average value of the thickness of the coating layer measured in five places was calculated. Moreover, the composition of the coating layer of the obtained sample was measured. Specifically, the cross section of the sample facing the metal evaporation source was measured using EDS. These measurement results are shown in Table 10.

  After measuring the average thickness of the coating layer, the cross-section polished surface of the coated tool was observed by the EBSD method using FE-SEM, and the average particle size of the hard particles of the substrate was determined. The EBSD was set such that a boundary having a step size of 0.01 μm, a measurement range of 2 μm × 2 μm, and an orientation difference of 5 ° or more was regarded as a grain boundary. Next, a value five times the average particle size of the hard particles of the base material was determined, and this value was determined as the reference length S. Using a FE-SEM, a reflected electron image of the cross-section polished surface at the interface between the base material and the coating layer in a range including a length equal to or greater than the reference length S was taken. Using a commercially available image analysis software, the total area A and the total area B of the hard particles in contact with the coating layer were determined from the photographed reflected electron image. Table 11 shows the average particle size and B / A of the hard particles of the substrate.

  Then, the structure | tissue which removed the droplet of diameter 100nm or more from the cross-section grinding | polishing surface of the coating layer was observed by the EBSD method by FE-SEM, and the particle size of the particle | grains of the coating layer was calculated | required. The EBSD was set such that a boundary having a step size of 0.01 μm, a measurement range of 2 μm × 2 μm, and an orientation difference of 5 ° or more was regarded as a grain boundary. The cumulative frequency of the number of particles in the coating layer with respect to the average particle size of the particles in the coating layer was determined when the total number of particles in the coating layer observed was 100%. Average particle diameters at which the cumulative frequency was 50% and 80% were obtained. Table 12 shows the average particle diameters with cumulative frequencies of 50% and 80%.

  From Table 11 and Table 12, invention products 11 and 12 are particles in which the B / A relating to the hard particles of the base material is in the range of 0.2 or more and less than 0.5, and the cumulative frequency of the particles of the coating layer is 50%. It can be seen that the diameter is in the range of 0.1 μm or more and 0.2 μm or less, and the particle diameter at which the cumulative frequency of particles in the coating layer is 80% is in the range of 0.25 μm or more and 0.45 μm or less.

  Using the obtained sample, face milling was performed in the same manner as in Example 1 under test conditions 1 and 2. Peel resistance was evaluated under test condition 1, and wear resistance and fracture resistance were evaluated under test condition 2.

  Table 13 shows the peeled area when the processing length is 2.0 m under Test Condition 1.

  From Table 13, it was confirmed that the inventive product had a smaller peeled area of the coating layer than the comparative product. From the above results, it was confirmed that the inventive product is superior in peel resistance to the comparative product.

  Table 14 shows the machining lengths up to the tool life under Test Condition 2.

  As shown in Table 14, it can be seen that the invention products are normally worn in all samples, and have better fracture resistance than the comparative products. When the invention product is compared with a comparative product whose damage form is normal wear, it can be seen that the processing length of the invention product is 4.9 m or more, which is longer than the comparison product of 3.9 m. From this result, it can be seen that the inventive product has a longer tool life than the comparative product.

  The coated tool of the present invention is excellent in wear resistance, peel resistance and chipping resistance, and has a longer life than conventional tools, and therefore has high industrial applicability.

Claims (7)

A coated tool comprising a substrate and a coating layer formed on the surface of the substrate,
The substrate includes a plurality of hard particles and a binder phase that binds the plurality of hard particles,
The coating layer includes one or more compound layers,
The compound layer is a layer of a compound containing Ti and N,
The average thickness of the coating layer is 0.6 μm or more and 8.0 μm or less,
A coated tool having a B / A value determined by the following procedures (1) to (6) of 0.27 or more and less than 0.5 in a cross section of 60% or more of a part involved in cutting .
(1) A cross section perpendicular to the surface of the substrate is extracted in a direction parallel to the surface of the substrate by a reference length S that is 5 times or more the average particle diameter of the hard particles.
(2) In the extracted cross section, the total area A of the cross section of the hard particles in contact with the coating layer is obtained.
(3) At the boundary surface between the coating layer and the base material, the first boundary portion D1 at the deepest position among the plurality of boundary portions formed between the hard particles adjacent to each other, and 2 The second boundary portion D2 at the deepest position is determined.
(4) A line segment L passing through the first boundary portion D1 and the second boundary portion D2 is drawn.
(5) The total area B of the cross section which exists in the coating layer side rather than the said line segment L among the cross sections of the said hard particle which is in contact with the said coating layer is calculated | required.
(6) The value of B / A is obtained. The coating layer includes a plurality of particles,
The particle size d50 when the cumulative frequency based on the number of the plurality of particles contained in the coating layer is 50% is 0.1 μm or more and 0.2 μm or less,
The coated tool according to claim 1, wherein the particle size d80 when the cumulative frequency based on the number of the plurality of particles contained in the coating layer is 80% is 0.25 µm or more and 0.45 µm or less.   The coated tool according to claim 1 or 2, wherein an average particle diameter of the hard particles contained in the substrate is 0.3 µm or more and 5 µm or less.   The hard particles contained in the base material are at least one metal element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W, and C, N, O and B The coated tool according to any one of claims 1 to 3, wherein the coated tool is a particle of a compound containing at least one nonmetallic element selected from the group consisting of: The coated tool according to any one of claims 1 to 4, wherein the part involved in the cutting is a part other than a screw hole of the coated tool. The coated tool according to any one of claims 1 to 5, wherein a value of B / A is 0.27 or more and less than 0.5 in a cross-section of 70% or more of a portion involved in the cutting. . The coated tool according to any one of claims 1 to 5, wherein a value of B / A is not less than 0.27 and less than 0.5 in a cross section of 80% or more of a portion involved in the cutting. .