JP2015033758A - Surface-coated cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-coated cutting tool excellent in pitching resistance and wear resistance.SOLUTION: A surface-coated cutting tool of this invention is characterized in that (a) a hard coating layer comprises a compound nitride layer of Al and Cr, and the content ratio of Cr in the total content of Al and Cr is 0.2 to 0.5 (atomic ratio); (b) the hard coating layer has a mixed composition of granular crystal grains having an average diameter of 0.2-1 μm and fine crystal grains having that of 0.08 μm or less in a range from the blade edge on a flank of the surface-coated cutting tool to a position separated therefrom by 100 μm, and the crystal grain diameter length percentage of the fine crystal grain having a grain size less than 0.1 μm accounts for 10-50% of the mixed composition; and (c) in the interface between the hard coating layer and a tool substrate in a range from the blade edge on the flank of the surface-coated cutting tool to the position separated therefrom by 100 μm, the crystal grain diameter length percentage accounted for by the grain having a size of 0.15 μm or less is 20% or less, and further preferably, crack occupancy is 0.3 to 1.0, 80% or more of the whole crack is retained inside the hard coating layer, and the crack penetrates the hard coating layer having a large crystal size.

Description

  The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool) that exhibits excellent chipping resistance and wear resistance in a hard coating layer when cutting difficult-to-cut materials such as stainless steel.

  In general, for coated tools, throwaway inserts that are detachably attached to the tip of the cutting tool for turning and planing of various steel and cast iron materials, drilling of the work material, etc. There are also drills used in the above, solid type end mills used for chamfering, grooving, shoulder processing, etc. of the work material, and the same as the solid type end mills with the throwaway tip attached detachably Slow-away end mill tools that perform cutting work are known.

For example, as shown in Patent Document 1, as a coated tool, a composite nitride of Al and Cr is formed on the surface of a base (hereinafter referred to as a tool base) made of tungsten carbide (hereinafter referred to as WC) based cemented carbide. A coating tool formed by vapor-depositing a hard coating layer composed of a layer [hereinafter referred to as (Al, Cr) N] is known. In such a conventional coating tool, the (Al, Cr) Since the Cr) N layer has excellent high-temperature hardness, heat resistance, high-temperature strength, high-temperature oxidation resistance, etc., it is known to exhibit excellent cutting performance.
In the conventional coated tool, for example, as shown in FIG. 1, the tool base is loaded into an arc ion plating apparatus which is a kind of physical vapor deposition apparatus, and the tool base is heated to 500 ° C. with a heater. In the heated state, arc discharge is generated under the condition of current: 90 A between the anode electrode and the cathode electrode on which an Al—Cr alloy having a predetermined composition is set, and at the same time, nitrogen gas is introduced into the apparatus as a reaction gas. Then, the reaction atmosphere is 2 Pa, while the (Al, Cr) N layer is formed on the surface of the tool base by vapor deposition under the condition that a bias voltage of −100 V is applied to the tool base. It is also known that it can.

By the way, in the coated tool, various proposals have been made for the structure of the hard coating layer in order to improve its cutting performance, particularly chipping resistance, wear resistance, and the like.
For example, Patent Document 2 discloses that the coating layer is made of columnar crystals as a coating tool that improves chipping resistance by suppressing chipping of the coating layer on the rake face, and improves wear resistance on the flank face. The coating layer thickness at the rake face is smaller than the coating layer thickness at the flank face, and the average crystal width of the upper layer region on the coating layer surface side is larger than the average crystal width of the lower layer region on the coating layer substrate side. The ratio of the thickness of the upper layer region to the coating layer thickness at the rake face is smaller than the ratio of the thickness of the upper layer region to the coating layer thickness at the flank face, and the average crystal width of the columnar crystals at the rake face Describes a coated tool (end mill) that is smaller than the average crystal width of the columnar crystals at the flank face.
Further, for example, Patent Document 3 discloses a coating tool formed on a substrate as a coating tool having a coating having both wear resistance and toughness and excellent adhesion to the substrate. One coating layer, the first coating layer includes a fine structure region and a coarse structure region, and the fine structure region has an average crystal grain size of a compound constituting it of 10 to 200 nm, and An average compressive stress which is present in a range of 50% or more of the total thickness of the first coating layer from the surface side of one coating layer and is a stress in a range of −4 GPa to −2 GPa. The first coating layer has a stress distribution in the thickness direction, and has two or more maximum values or minimum values in the stress distribution, and these maximum values or minimum values are on the surface side in the thickness direction. Coated tools with higher compressive stress It is.

Japanese Patent No. 3969230 JP 2008-296290 A JP2011-67883A

In recent years, the performance of cutting devices has been dramatically improved, while on the other hand, there has been a strong demand for labor saving, energy saving, and cost reduction for cutting, and as a result, cutting has been performed under more severe cutting conditions. It is coming.
The above conventional coated tools can improve chipping resistance, chipping resistance, and wear resistance to some extent, but if this is used for more severe cutting such as stainless steel, chipping is likely to occur. Or, wear and wear increase, and due to this, the service life is reached in a relatively short time.

  Therefore, the present inventors have provided a hard coating layer in order to provide a coated tool that has excellent chipping resistance as well as wear resistance in cutting processing of stainless steel and the like, and exhibits excellent cutting performance over a long period of use. As a result of earnest research on the crystal structure of the following, the following knowledge was obtained.

  Conventionally, as a means for forming a hard coating layer, a CVD method, a PVD method, or the like is generally employed as a means for forming a coated tool. For example, an arc ion plating method (hereinafter referred to as a PVD method) When the hard coating layer made of (Al, Cr) N is formed by the AIP method), as shown in Patent Document 1, the tool base is inserted into the apparatus and a predetermined bias voltage is applied. At the same time, an arc discharge is generated between the anode electrode and the Al—Cr alloy target having a predetermined composition while the apparatus is heated to a predetermined temperature, and simultaneously nitrogen gas is introduced into the apparatus as a reaction gas, and a predetermined pressure is applied. A hard coating layer was formed by vapor deposition in the reaction atmosphere (see FIG. 1).

  The inventors applied a magnetic field between the tool base and the target when forming the hard coating layer made of (Al, Cr) N by the conventional AIP method, and measured the influence of the magnetic field on the structure of the hard coating layer. As a result of investigation and investigation, it is possible to adjust the grain size, formation region, and distribution of crystal grains constituting the hard coating layer by performing the formation of the hard coating layer by the AIP method in a magnetic field having a predetermined strength. The hard coating layer within 100 μm from the cutting edge of the hard coating layer is configured as a mixed structure of granular crystal grains having a predetermined average grain size and fine crystal grains, and the crystal grain size of the crystal grains of 0.15 μm or less The length ratio is also set to 20% or less, or further, the crack occupancy rate of continuous cracks formed at the corner portion at the end of the cutting edge is adjusted to 0.3 to 1.0, and 80% or more of the number was present only in the hard coating layer, and such a hard coating layer was provided by penetrating a hard coating layer having a large crystal grain size from one end to the other end of the continuous crack. It has been found that the coated tool exhibits excellent chipping resistance and wear resistance in cutting of stainless steel and the like, and exhibits excellent cutting performance over a long period of use.

This invention has been made based on the above findings,
“(1) In a coated tool in which a hard coating layer having an average layer thickness of 2 to 10 μm is vapor-deposited on the surface of a tool base composed of a tungsten carbide-based cemented carbide,
(A) The hard coating layer is composed of a composite nitride layer of Al and Cr, and the content ratio of Cr in the total amount of Al and Cr in the layer is 0.2 to 0.5 (however, atomic ratio) And
(B) In the range from the cutting edge on the flank of the above coated tool to a position 100 μm away, the hard coating layer is composed of granular crystal grains having an average grain diameter of 0.2 to 1 μm and fine crystals having an average grain diameter of 0.08 μm or less. The crystal grain size ratio of fine crystal grains having a grain size of less than 0.1 μm occupies 10 to 50% of the above-mentioned mixed structure,
(C) At the interface between the tool base and the hard coating layer in the range from the cutting edge on the flank face of the coated tool to a position 100 μm away, the crystal grain size length ratio occupied by crystal grains having a grain size of 0.15 μm or less is 20 Coated tool characterized by being less than or equal to%.
(2) When the cutting edge angle of the coated tool is α degrees, and the occupation angle of the continuous crack formed in the hard coating layer at the corner portion of the cutting edge within the angle range of the α degrees is β degrees, The covering tool according to (1), wherein the crack occupation ratio β / α is 0.3 to 1.0.
(3) The number of continuous cracks of 80% or more of the total number of the above-mentioned continuous cracks exists only in the hard coating layer without penetrating the hard coating layer outermost surface and the interface between the tool base and the hard coating layer, And from one end part of the continuous crack to the other end part, the crystal grain size length ratio occupied by crystal grains having a grain size of 0.1 μm or more penetrates a hard coating layer of 80% or more. The coated tool according to (2).
(4) A method of manufacturing a surface-coated cutting tool in which a hard coating layer having an average layer thickness of 2 to 10 μm is formed on the surface of a tool base composed of a tungsten carbide-based cemented carbide, comprising an anode electrode, Al A base charging step of charging a tool base made of a tungsten carbide-based cemented carbide alloy into an arc ion plating apparatus including a target made of a Cr alloy and a magnetic force generation source provided on the back side of the target; A vapor deposition step of vapor-depositing and forming a hard coating layer composed of a composite nitride layer of Al and Cr on the tool base, the vapor deposition step comprising a gas introduction step of introducing nitrogen gas into the arc ion plating apparatus; An application step of applying a magnetic field having an integrated magnetic force within a range of 45 to 100 mT × mm by the magnetic force generation source between the target and the tool base; A discharge process for generating an arc discharge between the target and the anode electrode while applying a bias voltage to the tool base; and a rotation and revolution process for rotating and revolving the tool base in the arc ion plating apparatus. And when the tool base is closest to the target, the tool base is supported so that a part or all of the flank of the tool base and the surface of the target on the tool base side are horizontal. The method for producing a coated tool according to any one of (1) to (3), wherein: "
It has the characteristics.

Next, the coated tool of the present invention will be described in detail.
(A) Type of hard coating layer, average layer thickness:
The hard coating layer of the present invention is composed of a composite nitride layer of Al and Cr ((Al, Cr) N layer).
In the (Al, Cr) N layer, the Al component improves the high temperature hardness and heat resistance, the Cr component improves the high temperature strength, and the high temperature oxidation resistance is improved by the coexistence of Cr and Al. It is already well known as a hard coating layer having excellent hardness, heat resistance, high temperature strength and high temperature oxidation resistance.
In the (Al, Cr) N layer of the present invention, if the Cr content ratio (atomic ratio, the same applies hereinafter) in the total amount with Al is less than 0.2, it is difficult to ensure high temperature strength during cutting. On the other hand, when the Cr content ratio (atomic ratio) in the total amount with Al exceeds 0.5, the Al content ratio is relatively reduced, resulting in a decrease in high-temperature hardness and a decrease in heat resistance. As a result, wear resistance deteriorates due to the occurrence of uneven wear, the occurrence of thermoplastic deformation, etc., so the Cr content (atomic ratio) in the total amount with Al is 0.2 to 0.5. It is necessary to be.
In addition, if the average thickness of the hard coating layer made of the (Al, Cr) N layer is less than 2 μm, excellent wear resistance cannot be exhibited over a long period of time, resulting in a short tool life. When the average layer thickness exceeds 10 μm, chipping is likely to occur at the blade edge portion, so the average layer thickness needs to be 2 to 10 μm.
In the present invention, the average layer thickness was measured as follows. A section on the flank side is cut out from the tool base blade edge, and the section is observed with an SEM. The distance from the interface between the tool base and the hard coating layer to the surface of the hard coating layer was measured at any five locations, and the average value was taken as the average layer thickness.

(B) Layer structure of hard coating layer composed of (Al, Cr) N layer:
In the present invention, in the range from the cutting edge on the flank to a position 100 μm away, the hard coating layer is composed of granular crystal grains having an average grain diameter of 0.2 to 1 μm and fine crystal grains having an average grain diameter of 0.08 μm or less. The crystal grain length ratio of fine crystal grains composed of a mixed structure and having a particle diameter of less than 0.1 μm occupies 10 to 50% of the mixed structure.
In addition, at the interface between the tool base and the hard coating layer, the crystal grain length ratio occupied by crystal grains having a grain size of 0.15 μm or less is set to 20% or less.
In addition, as shown in FIG. 3, the “blade edge” in the present invention is “the portion closest to the tip of the linear cutting blade excluding the conical portion of the corner portion at the tip of the cutting blade”. Define that there is.
Further, the “granular crystal” herein means crystal grains having an aspect ratio of 1 or more and 6 or less and a grain size of 0.1 μm or more. “Fine crystals” means crystal grains having an aspect ratio of 1 or more and 6 or less and a grain size of less than 0.1 μm. The aspect ratio is calculated as the ratio of the length of the longest diameter (long side) to the diameter (short side) perpendicular to the crystal grain cross section, with the long side as the numerator and the short side as the denominator.
In addition, “the crystal grain size length ratio of fine crystal grains having a grain size of less than 0.1 μm” means that the grain size of a plurality of crystal grains is measured and the grain size relative to the sum of all the measured crystal grain lengths is The ratio of the sum of crystal grain lengths of less than 0.1 μm is indicated, and “the ratio of crystal grain length occupied by crystal grains having a grain size of 0.15 μm or less” is the measurement of the grain size of a plurality of crystal grains. , The ratio of the sum of crystal grain lengths with a grain size of 0.15 μm or less to the sum of all measured crystal grain lengths.

The layer structure of the hard coating layer of the present invention will be described in detail below.
In the present invention, in the range from the cutting edge on the flank to a position 100 μm away, the hard coating layer is mainly composed of granular crystal grains having an average grain diameter of 0.2 to 1 μm and fine crystals having an average grain diameter of 0.08 μm or less. A hard coating layer is formed as a mixed structure with grains, but the compression formed in the hard coating layer when the crystal grain length ratio of fine crystal grains having a grain size of less than 0.1 μm is less than 10% in the mixed structure. Since the stress value becomes small, the wear resistance of the hard coating layer is lowered. On the other hand, if the crystal grain length ratio of fine crystal grains having a grain size of less than 0.1 μm exceeds 50% in the mixed structure, the hard coating layer Since the value of the compressive stress formed in the layer becomes too large and chipping is likely to occur at the time of cutting, the crystal grain size ratio of fine crystal grains having a grain size of less than 0.1 μm in the mixed structure is 10 to 50%.
The crystal grain length ratio of the granular crystal grains having a grain size of 0.1 μm or more needs to be present at a ratio of 50 to 90%. If it exceeds 90%, the compressive stress value becomes small and the hardness becomes too small, and the wear resistance of the hard coating layer decreases. On the other hand, if it is less than 50%, the compressive stress value becomes large and the hardness is low. Becomes too large and chipping is likely to occur at the time of cutting. Therefore, the crystal grain length ratio of the granular crystal grains having a grain size of 0.1 μm or more in the mixed structure needs to be 50 to 90%. is there.
In addition, when the average grain size of the granular crystal grains exceeds 1 μm, the value of the compressive stress formed in the hard coating layer is reduced, so that the wear resistance of the hard coating layer is reduced. It is necessary to set the upper limit of the diameter to 1 μm.

In addition, at the interface between the tool base and the hard coating layer, the crystal grain length ratio occupied by crystal grains having a grain size of 0.15 μm or less needs to be 20% or less.
Here, the crystal grains of the hard coating layer at the interface between the tool base and the hard coating layer are the crystal grains formed in the region of 0.5 μm thickness from the interface between the tool base and the hard coating layer in the hard coating layer. means.
In the present invention, the distribution of the crystal grains of 0.15 μm or less was determined as described above in order to ensure sufficient wear resistance with the hard coating layer coated on the blade edge and to suppress the occurrence of chipping. If the crystal grain length ratio of crystal grains having a grain size of 0.15 μm or less exceeds 20%, the compressive residual stress in the hard coating layer increases, and chipping is performed in cutting difficult-to-cut materials such as stainless steel. It is because it becomes easy to generate.
In the present invention, the measurement of the crystal grain size of the hard coating layer on the flank and the calculation of the average crystal grain size were performed as follows.
A section on the flank side is cut out from the tool base blade edge, and the section is observed with an SEM. Crystal grains formed in a region having a depth of 0.5 μm from the surface of the hard coating layer, crystal grains formed in a region having a thickness of 0.5 μm from the interface between the tool base and the hard coating layer in the hard coating layer, and A straight line is drawn in parallel with the tool base surface at the crystal grains present in the intermediate region between the hard coating layer surface and the tool base surface, and the distance between the crystal grain boundaries is defined as the grain size. The position where a straight line is drawn parallel to the surface of the tool base is the position where the longest crystal grain size is obtained in each crystal grain. In each region, the average of the flank upper cutting edge, and the crystal existing within a range of 10 μm in width at a total of nine positions, three positions on the flank face, 50 μm away from the cutting edge, and 100 μm away from the cutting edge. Measure crystal grain size. In measuring a particle diameter of 10 μm in width, measurement data of 5 μm on the blade edge side and 5 μm on the opposite side to the blade edge were used centering on each measurement point. However, at the position of the cutting edge on the flank, the measurement was performed within a range of 10 μm in width of 5 μm on the side of the cutting edge and 5 μm on the opposite side to the cutting edge, with a position 5 μm away from the cutting edge. The average value of crystal grains having a grain size of 0.1 μm or more in all nine regions is defined as “average grain diameter of granular crystal grains”. The average value of crystal grains having a grain size of less than 0.1 μm is defined as “average grain size of fine crystal grains”.
Moreover, the measuring method of the crystal grain size length ratio occupied by crystal grains having a grain size of less than 0.1 μm is the crystal grain size measured at the three interfaces, three surfaces, and three intermediate regions where the particle size was measured. All measured data of are used. The sum of crystal grain sizes with a grain size of less than 0.1 μm with respect to the sum of all measured crystal grain sizes was defined as “the ratio of crystal grain length occupied by fine crystal grains”.
Moreover, the measurement method of the crystal grain size length ratio occupied by crystal grains having a grain size of 0.15 μm or less at the interface uses all measurement data at the three interfaces where the grain size is measured. The sum of the crystal grain sizes with a grain size of 0.15 μm or less relative to the sum of the measured total crystal grain sizes was defined as “the ratio of the crystal grain length occupied by the crystal grains with a grain size of 0.15 μm or less”.

Further, in the present invention, as shown in FIG. 4, the cutting edge angle of the coated tool is α degrees, and the occupation angle of the continuous cracks formed in the hard coating layer within the angle range of the α degrees is β degrees. In this case, the corner crack occupation ratio β / α at the tip of the cutting edge is preferably 0.3 to 1.0, and more preferably β / α is 0.3 to 0.9.
The reason is as follows.
When a hard coating layer is formed on the surface of a tool base using an arc ion plating apparatus (AIP apparatus), compressive residual stress is accumulated in the layer, and particularly in a layer having a large crystal grain size, Compressive residual stress concentrates on the grain boundary and tends to be the origin of cracks.
However, according to the present invention, since cracks are formed in advance in the hard coating layer at the corner portion at the tip of the cutting edge, the concentration of residual stress is reduced. A reduction in cutting performance can be suppressed.
However, when β / α is less than 0.3, the effect of suppressing the concentration of compressive residual stress cannot be expected, so β / α is set to 0.3 or more.
From the viewpoint of the effect of suppressing the concentration of compressive residual stress, it is not necessary to provide an upper limit to the value of β / α (that is, β / α is 0.3 to 1.0), but the value of β / α is 1. The closer to 0, the easier the interface peeling at the hard coating layer / tool base interface occurs, so the value of β / α is preferably 0.3 to 0.9.

Here, the crack and crack occupation rate in the present invention are defined as follows.
First, the crack in this invention means the crack formed in the hard coating layer containing the corner part of a cutting-blade front-end | tip. This crack can be confirmed by observing a cross-sectional SEM photograph of the coated tool, for example, at a magnification of 10,000 times. The crack in the present invention means a crack having a width of 30 nm or more. The point where the width of the crack tapers at the end and the width of the crack is less than 30 nm is defined as the end of the crack.
In addition, as shown in FIG. 4, the crack occupancy rate in the present invention is centered on the intersection of the flank normal passing through the cutting edge A on the flank and the normal of the rake face passing through the cutting edge B on the rake face. , The angle formed by AOB is referred to as the blade edge angle α (degrees).
Further, for continuous cracks formed in the hard coating layer at the corner portion at the tip of the cutting edge, when a line in contact with the end portions C and D of one continuous crack is drawn from the center O, C—O The angle formed by -D is defined as the occupied angle β (degrees) of the continuous crack. However, when a crack crosses the extension line of OA or OB, the intersections of the extension line and the crack are C and D, respectively. When there are a plurality of cracks in the hard coating layer at the corner portion at the tip of the cutting edge, a continuous crack showing the maximum occupation angle is used.
The value of (occupation angle β of continuous crack) / (blade edge angle α) is defined as the crack occupancy rate.
In the coated tool of the present invention, the hard coating layer composed of the (Al, Cr) N layer has a mixed structure of granular crystal grains and fine crystal grains, and the crystal grain length ratio of the fine crystal grains is 10 to 50%. In addition, at the interface from the cutting edge on the flank to a position 100 μm away, the crystal grain length ratio occupied by the crystal grains having a grain size of 0.15 μm or less is set to 20% or less, so β / α is 0.3 to 1.
At the same time, 80% or more of the continuous cracks are present only in the hard coating layer without penetrating the outermost surface of the hard coating layer and the interface between the tool base and the hard coating layer. As a result, the compressive residual stress in the hard coating layer is relieved, thereby improving the strength of the hard coating layer at the cutting edge. If the number of cracks of 20% or more of the continuous cracks penetrates the outermost surface of the hard coating layer, not only the hard coating layer is likely to be chipped but also the hard coating layer is peeled off or self-destructed. Occur. On the other hand, when the number of cracks of 20% or more of the continuous cracks penetrates the interface between the tool base and the hard coating layer, the adhesion at the interface between the tool base and the hard coating layer is reduced, and cutting is performed. Chipping and peeling easily occur during processing.
Furthermore, the compressive residual stress is reduced from one end portion of the continuous crack to the other end portion through the hard coating layer having a crystal grain size length ratio of 80% or more occupied by crystal grains having a grain size of 0.15 μm or more. By releasing / relaxing the compressive residual stress at the crystal grain boundaries of the crystal grains having a grain size of 0.1 μm or more which tend to concentrate and become the starting point of cracking, the occurrence of chipping during cutting can be suppressed.

(C) Vapor deposition of hard coating layer The hard coating layer of the present invention uses an arc ion plating apparatus (AIP apparatus) as shown in FIGS. While maintaining the temperature at C, the tool substrate is rotated and revolved in the AIP apparatus, and vapor deposition is performed while applying a predetermined magnetic field (integrated magnetic force is 45 to 100 mT x mm) between the center of the target surface and the tool substrate closest to the target. Can be formed.
For example, one of the AIP devices is provided with a cathode electrode made of a Ti electrode for substrate cleaning, and the other is provided with a target (cathode electrode) made of a 70 at% Al-30 at% Cr alloy,
First, a tool substrate made of tungsten carbide (WC) -based cemented carbide is cleaned and dried, mounted on a rotary table in an AIP apparatus, and 100 A between the Ti electrode and the anode electrode for cleaning the substrate in vacuum. An arc discharge is generated, and the tool base surface is bombarded while applying a bias voltage of −1000 V to the tool base,
Next, a magnetic field having an integrated magnetic force of 45 to 100 mT × mm from the surface center of the Al—Cr alloy target to the tool base closest to the target is applied,
Next, nitrogen gas is introduced into the apparatus as a reaction gas to achieve an atmospheric pressure of 9.3 Pa, the temperature of the tool base is maintained at 370 to 450 ° C., and a bias voltage of −50 V is applied to the tool base while Al—Cr A 100 A arc discharge is generated between the alloy target (cathode electrode) and the anode electrode, and when the tool base is closest to the target, a part or all of the flank and the target surface are horizontal. By vapor deposition while supporting and rotating on the substrate, a hard coating layer composed of the (Al, Cr) N layer having the layer structure of the present invention and compressive residual stress can be formed by vapor deposition.
The magnetic field is applied between the Al—Cr alloy target and the tool base, for example, by installing an electromagnetic coil or permanent magnet as a magnetic field generation source around the cathode, or permanently in the center of the AIP apparatus. The magnetic field can be formed by any means such as disposing a magnet.
Here, the integrated magnetic force in the present invention is calculated by the following calculation method.
With a magnetometer, the magnetic flux density is measured at intervals of 10 mm on a straight line from the center of the Al—Cr alloy target to the position of the tool base. The magnetic flux density is expressed in units of mT (millitesla), and the distance from the target surface to the position of the tool base is expressed in units of mm (millimeters). Furthermore, when the distance from the target surface to the position of the tool base is the horizontal axis and the magnetic flux density is represented by a graph of the vertical axis, a value corresponding to the area is defined as an integrated magnetic force (mT × mm).
Here, the position of the tool base is the position closest to the Al—Cr alloy target. Note that the magnetic flux density may be measured in a state where a magnetic field is formed, not in a discharge, for example, in a state where the magnetic field is not discharged under atmospheric pressure.

  The coated tool of the present invention includes a hard coated layer composed of an (Al, Cr) N layer, and further has a granular crystal having an average particle diameter of 0.2 to 1 μm in a range up to a position 100 μm away from the cutting edge on the flank. A mixed structure of grains and fine crystal grains having an average grain size of 0.08 μm or less, and the crystal grain length ratio of the fine crystal grains occupies 10 to 50% of the mixed structure, At the interface of the hard coating layer, the crystal grain size length ratio occupied by crystal grains having a grain size of 0.15 μm or less is 20% or less, and the crack occupation ratio β / α is 0.3 to 1.0, A crystal in which 80% or more of the continuous cracks are present only in the hard coating layer and from one end to the other end of the continuous crack is occupied by crystal grains having a grain size of 0.1 μm or more. It penetrates a hard coating layer with a particle size length ratio of 80% or more. From, in cutting of difficult-to-cut materials such as stainless steel, excellent chipping resistance, exhibit wear resistance, is to exhibit excellent cutting performance over a long period of use.

The schematic explanatory drawing of the conventional AIP apparatus is shown. The schematic explanatory drawing of the AIP apparatus for producing the covering tool of this invention is shown, (a) is a top view, (b) shows a side view. The longitudinal cross-sectional schematic explanatory drawing of the coating tool of this invention is shown. The schematic explanatory drawing for demonstrating the relationship between the blade edge | tip angle (alpha) of the covering tool of this invention, the occupation angle (beta) of a continuous crack, and a crack occupation rate is shown. The schematic diagram explaining the crystal grain diameter in the site | part which the one end part of the continuous crack of this invention penetrates from the other end part is shown.

  Next, the coated tool of the present invention will be specifically described with reference to examples.

As raw material powders, medium coarse WC powder having an average particle diameter of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, ZrC of 1.2 μm Powder, 2.3 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C [by mass ratio, TiC / WC = 50/50] powder, and 1 .8 μm Co powder was prepared, each of these raw material powders was blended in the blending composition shown in Table 5, and then added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and then pressed into a predetermined shape at a pressure of 100 MPa. Extruded and pressed into various types of green compacts, and these green compacts were heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a temperature increase rate of 7 ° C./min in a 6 Pa vacuum atmosphere. Conditions for furnace cooling after holding at this temperature for 1 hour Sintered to form a round tool sintered body for forming a tool base having a diameter of 10 mm, and further, from the round bar sintered body, the diameter x length of the cutting edge portion is 6 mm x 13 mm by grinding. The tool base (end mill) 1 to 3 made of a WC-based cemented carbide having a two-blade ball shape with a twist angle of 30 degrees, and the diameter of the cutting edge portion × length is 10 mm × 22 mm. Tool bases (end mills) 4 to 5 made of a WC-base cemented carbide having a square shape were manufactured.

(A) Each of the tool bases 1 to 5 described above is ultrasonically cleaned in acetone and dried, at a position spaced apart from the central axis on the rotary table of the AIP apparatus shown in FIG. 2 by a predetermined distance in the radial direction. Attached along the outer periphery, a Ti cathode electrode for bombard cleaning is arranged on one side of the AIP apparatus, and a target (cathode electrode) made of a 70 at% Al-30 at% Cr alloy is arranged on the other side,
(B) First, the tool base is heated to 500 ° C. with a heater while the inside of the apparatus is evacuated and kept in vacuum, and then a DC bias voltage of −1000 V is applied to the tool base that rotates while rotating on the rotary table. And an arc discharge is caused by flowing a current of 100 A between the Ti cathode electrode and the anode electrode, thereby bombarding the surface of the tool substrate,
(C) Next, various magnetic fields are applied so that the integrated magnetic force from the center of the surface of the Al—Cr alloy target to the tool base is in the range of 45 to 100 mT × mm.
Here, a method of calculating the integrated magnetic force will be described below. With a magnetometer, the magnetic flux density is measured at intervals of 10 mm on a straight line from the center of the Al—Cr alloy target to the position of the tool base. The magnetic flux density is expressed in units of mT (millitesla), and the distance from the target surface to the position of the tool base is expressed in units of mm (millimeters). Furthermore, when the distance from the target surface to the position of the tool base is the horizontal axis and the magnetic flux density is represented by a graph of the vertical axis, a value corresponding to the area is defined as an integrated magnetic force (mT × mm). Here, the position of the tool base is the position closest to the Al—Cr alloy target. The magnetic flux density was measured in a state in which a magnetic field was formed and not discharged in advance under atmospheric pressure.
(D) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 9.3 Pa, and the temperature of the tool base rotating while rotating on the rotary table is within a range of 370 to 450 ° C. And a DC bias voltage of −50 V is applied, and a current of 100 A is passed between the Al—Cr alloy target and the anode electrode to generate an arc discharge. By vapor-depositing a hard coating layer comprising an (Al, Cr) N layer of the indicated composition and target average layer thickness,
Surface coated end mills 1 to 5 (hereinafter referred to as the present invention 1 to 5) as the coated tools of the present invention were produced, respectively.
In the AIP apparatus shown in FIG. 2, when the tool base is closest to the Al—Cr alloy target, it is mounted and supported so that a part or all of the flank and the Al—Cr alloy target surface are horizontal. .

Comparative Example 1:
For the purpose of comparison, the condition of (c) in Example 1 was changed (that is, the integrated magnetic force from the center of the surface of the Al—Cr alloy target to the tool substrate was outside the range of 45 to 100 mT × mm), and ( The surface-coated end mill 1 as a comparative-coated tool was changed under the same conditions as in Example 1 except that the conditions of d) were changed (that is, the tool substrate was maintained at a temperature of less than 370 ° C. or higher than 450 ° C.). To 5 (hereinafter referred to as Comparative Examples 1 to 5), respectively. Furthermore, the content ratio of Cr in the total amount of Al and Cr in the coating layer from Example 1 is out of the range of 0.2 to 0.5 (however, the atomic ratio), or the average layer thickness of the coating layer is 2 Surface-coated end mills 6 to 10 (hereinafter referred to as Comparative Examples 6 to 10) outside the range of 10 μm were manufactured.

About this invention 1-5 produced above, in the range from the cutting edge on the flank to a position 100 μm away, the average layer thickness and crystal grain size of the hard coating layer in the longitudinal section are measured, and the average grain size of the fine crystal grains Calculate the diameter, the average grain size of the granular crystal grains, the crystal grain size length ratio of the fine crystal grains, and the crystal grain size length ratio of 0.15 μm or less, all of which are crystal grains having an aspect ratio of 1 to 6 It was confirmed. The aspect ratio is calculated as the ratio of the length of the longest diameter (long side) to the diameter (short side) perpendicular to the crystal grain cross section, with the long side as the numerator and the short side as the denominator.
Moreover, when the crystal grain length ratio of the fine crystal grains in the hard coating layer in the range from the blade edge to 100 μm was measured, it was confirmed that the fine crystal grains accounted for 10 to 50% in the mixed structure. .
Furthermore, when the crystal grain length ratio of the crystal grains having a grain size of 0.15 μm or less at the interface between the tool base and the hard coating layer in the range up to 100 μm away from the cutting edge was measured, it was confirmed that it was 20% or less. did.
On the other hand, when Comparative Examples 1 to 10 were observed and measured in the same manner as in the present invention, except for the surface coated end mill (Comparative Examples 9 and 10) where the average thickness of the coating layer was outside the range of 2 to 10 μm, The crystal grain length ratio of the crystal grains is outside the range of 10 to 50% in the mixed structure, or the crystal grain length ratio of the crystal grains having a grain size of 0.15 μm or less at the interface between the tool base and the hard coating layer is measured. As a result, it was 20% or more.
Tables 2 and 3 show the values measured and calculated above.

More specifically, the measurement method of the average layer thickness, the measurement method of the crystal grain size, and the measurement method of the crystal grain length ratio are as follows.
After polishing the cross section of the flank, including the corner portion at the tip of the coated tool, the cross section is observed with an SEM.
The distance from the interface between the tool base and the hard coating layer to the surface of the hard coating layer was measured at five locations, and the average value was taken as the average layer thickness. It should be noted that the measurement points are any five locations from the cutting edge on the flank to the position 100 μm away from the cutting edge on the flank.
Crystal grains formed in a region having a depth of 0.5 μm from the surface of the hard coating layer, and crystal grains formed in a region having a thickness of 0.5 μm from the interface between the tool substrate and the hard coating layer in the hard coating layer A straight line is drawn in parallel with the tool base surface in the crystal grains existing in the intermediate region between the hard coating layer surface and the tool base surface, and the distance between the crystal grain boundaries is defined as the grain size. In each region, the average of the flank upper cutting edge, and the crystal existing within a range of 10 μm in width at a total of nine positions, three positions on the flank face, 50 μm away from the cutting edge, and 100 μm away from the cutting edge. Measure crystal grain size. In measuring a particle diameter of 10 μm in width, measurement data of 5 μm on the blade edge side and 5 μm on the opposite side to the blade edge were used centering on each measurement point. However, at the position of the cutting edge on the flank, the measurement was performed within a range of 10 μm in width of 5 μm on the side of the cutting edge and 5 μm on the opposite side to the cutting edge, with a position 5 μm away from the cutting edge. The average value of crystal grains having a grain size of 0.1 μm or more in all nine regions is defined as “average grain diameter of granular crystal grains”. The average value of crystal grains having a grain size of less than 0.1 μm is defined as “average grain size of fine crystal grains”.
Moreover, the measuring method of the crystal grain size length ratio occupied by crystal grains having a grain size of less than 0.1 μm is the crystal grain size measured at the three interfaces, three surfaces, and three intermediate regions where the particle size was measured. All measured data of are used. The sum of the crystal grain sizes having a grain size of less than 0.1 μm with respect to the sum of the measured total crystal grain sizes was defined as “the ratio of crystal grain length occupied by crystal grains having a grain size of less than 0.1 μm”.
Moreover, the measurement method of the crystal grain size length ratio occupied by crystal grains having a grain size of 0.15 μm or less at the interface uses all measurement data at the three interfaces where the grain size is measured. The sum of the crystal grain sizes with a grain size of 0.15 μm or less relative to the sum of the measured total crystal grain sizes was defined as “the ratio of the crystal grain length occupied by the crystal grains with a grain size of 0.15 μm or less”.

Furthermore, while measuring the blade edge angle α of the present invention 1-5 and Comparative Examples 1-10, the occupation angle β of the continuous crack in the hard coating layer at the corner portion at the tip of the cutting edge was measured, and the crack occupation ratio β / The value of α was calculated.
In addition, what percentage of the total number of continuous cracks is present only in the hard coating layer without penetrating the hard coating layer outermost surface and the interface between the tool base and the hard coating layer. Further, the ratio of the crystal grain size length occupied by the crystal grains having a grain size of 0.1 μm or more at the part penetrating from one end to the other end of the continuous crack was measured.
Tables 2 and 3 show these values.
More specifically, the measurement method of the cutting edge angle α and the occupying angle β of the continuous crack is as follows.
Of the SEM images observed for measuring the crystal grain size, a cross-sectional SEM image of the tip of the cutting edge is used. The measurement conditions used were an observation magnification of 10,000 times and an acceleration voltage of 3 kV. FIG. 4 shows a cross-sectional SEM image (a) and a schematic diagram (b) of the cutting edge tip of the present invention 2. This will be described with reference to FIG. The cutting edge on the flank is A, and the cutting edge on the rake face is B. The perpendicular of the flank passing through A and the perpendicular of the rake face passing through B are drawn, and the intersection of both perpendiculars is set as the center O. The blade edge angle α (degrees) is an angle formed by AOB.
Further, regarding the continuous crack formed in the hard coating layer at the corner portion at the tip of the cutting edge, when the crack is projected from the center O, the point closest to the perpendicular of the flank passing through A is defined as C, and B Let D be the point closest to the normal of the rake face passing through. The occupying angle β (degrees) of continuous cracks is an angle formed by C-O-D. When there are a plurality of cracks in the hard coating layer at the corner portion at the tip of the cutting edge, the value calculated by the continuous crack showing the maximum value is defined as the occupation angle β of the continuous crack.
The value of (occupation angle β of continuous crack) / (blade edge angle α) is defined as the crack occupancy rate.
Furthermore, the ratio of the number of cracks existing only inside the hard coating layer, and the measurement of the ratio of the crystal grain size length occupied by the crystal grains having a grain size of 0.1 μm or more in the part penetrating from one end to the other end of the continuous crack More specifically, the law is as follows.
After polishing the cross section of the corner portion at the tip of the cutting edge, the cross section is observed with an SEM. Observe five or more cross-sections with different sites for the same sample. The observation conditions are: observation magnification: 10000 times, acceleration voltage: 3 kV. Of the total number of continuous cracks present in the hard coating layer at the corner at the tip of the cutting edge in each cross-section, the number of continuous cracks existing only in the hard coating layer without penetrating the surface of the hard coating layer and the tool substrate. The ratio of the sum of the total number is defined as the ratio of the number of cracks existing only inside the hard coating layer.
Further, in each cross section, the continuous crack having the maximum occupation angle β is used as a representative of the continuous crack in each cross section, and the particle diameter is 0.1 μm or more in the part penetrating from one end to the other end of the continuous crack. The crystal grain length ratio of crystal grains is measured. First, in each cross section, the length of the continuous crack is measured. The length of the hard coating layer exposed in the voids caused by the continuous cracks having the maximum occupied angle β is measured between C and D on the hard coating layer surface side and the tool substrate side, and the average value is continuously measured. The average value in each cross section is calculated as the crack length.
In addition, for crystal grains formed in the region of the hard coating layer exposed in the voids caused by continuous cracks, the linear distance between crystal grain boundaries in the direction parallel to the tool base surface is defined as the grain size. At the corner portion at the tip of the cutting edge, a curve drawn at a position equidistant from the point (contact point) in contact with the tangent on the surface of the tool base to the hard coating layer surface side in the direction perpendicular to the tangent is parallel to the tool base surface. . The position where the curve is drawn parallel to the surface of the tool base is the position where the longest crystal grain size is obtained in each crystal grain. Measure the particle size in the region of the hard coating layer surface side and the region of the tool base side in C to D of continuous cracks, respectively, and calculate the average value of the sum of the crystal grain sizes of 0.1 μm or more in each region, Furthermore, the average value in each cross section is calculated. The portion where the average value of the sum of the crystal grain sizes of each cross section having a grain size of 0.1 μm or more occupies the length of the average continuous crack in each cross section from one end to the other end of the continuous crack Is defined as the ratio of the crystal grain size length occupied by crystal grains having a grain size of 0.1 μm or more.
FIG. 5 is a schematic diagram for explaining the crystal grain size in a portion penetrating from one end portion of the continuous crack to the other end portion.

Next, among the end mills of the present invention 1-5 and Comparative Examples 1-10,
About this invention 1-3 and Comparative Examples 1-3, 6-8,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Rotational speed: 16000 min. ^-1 ,
Lateral cut: 2.0 mm,
Longitudinal cut: 0.3 mm,
Feed rate (per blade): 0.06 mm / tooth,
Cutting length: 340m,
A stainless steel groove cutting test was conducted under the above conditions (referred to as cutting condition A),
Moreover, about this invention 4, 5 and comparative examples 4, 5, 9, and 10,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 plate,
Rotational speed: 3200 min. ^-1 ,
Lateral cut: 10 mm,
Longitudinal cut: 1 mm,
Feed rate (per tooth): 0.07 mm / tooth,
Cutting length: 90m,
Conducting a groove cutting test of stainless steel under the conditions (referred to as cutting condition B)
In any groove cutting test, the flank wear width of the cutting edge was measured.
The measurement results are shown in Table 4.

WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder and Co powder all having an average particle diameter of 1 to 3 μm are prepared as raw material powders. These raw material powders are blended into the composition shown in Table 1, wet mixed by a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. Medium temperature: Sintered at 1400 ° C for 1 hour. After sintering, insert edge shape of ISO standard, SNGA120408 by applying honing of R: 0.03 to the cutting edge and further polishing. Tool bases 6 to 10 made of WC-base cemented carbide having

Next, the surfaces of these tool bases (inserts) 6 to 10 are ultrasonically cleaned in acetone and dried, and then inserted into the AIP apparatus shown in FIG. 2 under the same conditions as in Example 1 above. By forming a hard coating layer composed of an (Al, Cr) N layer having the composition shown in Table 6 and a target average layer thickness,
The coated carbide inserts of the present invention (hereinafter referred to as the present inventions 6 to 10) as the coated tools of the present invention were produced.

Comparative Example 2:
For comparison purposes, the tool base (inserts) 6 to 10 are composed of (Al, Cr) N layers having the compositions and target average layer thicknesses shown in Table 7 under the same conditions as in Comparative Example 1. By forming a hard coating layer,
Comparative example coated carbide inserts (hereinafter referred to as Comparative Examples 11 to 20) as comparative example coated tools were produced, respectively.

About this invention 6-10 produced above, the average layer thickness and crystal grain diameter of the hard coating layer of the longitudinal section in the range to the position away from the cutting edge on the flank 100 μm are measured, and the average grain diameter of the fine crystal grains The average grain size of the granular crystal grains, the crystal grain size length ratio of the fine crystal grains, and the crystal grain size length ratio of 0.15 μm or less are calculated, and all are crystal grains having an aspect ratio of 1 to 6 confirmed. The aspect ratio is calculated as the ratio of the length of the longest diameter (long side) to the diameter (short side) perpendicular to the crystal grain cross section, with the long side as the numerator and the short side as the denominator.
Moreover, when the crystal grain length ratio of the fine crystal grains in the hard coating layer was measured, it was confirmed that the crystal grain length ratio of the fine crystal grains occupied 10 to 50% in the mixed structure.
Furthermore, when the crystal grain length ratio occupied by the crystal grains having a grain size of 0.15 μm or less at the interface between the tool base and the hard coating layer was measured, it was also confirmed that it was 20% or less.
On the other hand, when Comparative Examples 11 to 20 were observed and measured in the same manner as in the present invention, the average thickness of the coating layer was fine except for the surface-coated inserts (Comparative Examples 19 and 20) outside the range of 2 to 10 μm. The crystal grain length ratio of the crystal grains is outside the range of 10 to 50% in the mixed structure, or the crystal grain length ratio of the crystal grains having a grain size of 0.15 μm or less at the interface between the tool base and the hard coating layer is measured. As a result, it was 20% or more.
Further, for the present inventions 6 to 10 and Comparative Examples 11 to 20, the values of the blade edge angle α, the continuous crack occupying angle β, and the crack occupying ratio β / α were also measured and calculated.
Furthermore, what percentage of the total number of continuous cracks is present only in the hard coating layer without penetrating the outermost surface of the hard coating layer and the interface between the tool base and the hard coating layer. Further, the ratio of the crystal grain size length occupied by the crystal grains having a grain size of 0.1 μm or more at the part penetrating from one end to the other end of the continuous crack was measured.
Tables 6 and 7 show the values measured and calculated above.

Next, in the state where all of the coated inserts of the present inventions 6 to 10 and Comparative Examples 11 to 20 are screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / SCM440 round bar,
Cutting speed: 100 m / min. ,
Incision: 1.5mm,
Feed: 0.3 mm / rev. ,
Cutting time: 3 minutes
A dry continuous cutting test of alloy steel (chromium molybdenum steel) under the above conditions (referred to as cutting condition C) was performed, and the flank wear width of the cutting edge was measured.
The measurement results are shown in Table 8.

From the results shown in Tables 4 and 8, the coated tool of the present invention has an average particle size of 0. 0 in the range where the hard coating layer composed of the (Al, Cr) N layer is located 100 μm away from the cutting edge on the flank. Having a mixed structure of 2-1 μm granular crystal grains and fine crystal grains having an average grain size of 0.08 μm or less, and the crystal grain length ratio of the fine crystal grains accounts for 10 to 50% of the mixed structure; At the interface between the tool base and the hard coating layer, the ratio of the crystal grain size length occupied by the crystal grains having a grain size of 0.15 μm or less is 20% or less. The continuous crack of 80% or more of the total number of continuous cracks exists only in the hard coating layer, and the particle size of one end to the other end of the continuous crack is 0. The ratio of crystal grain length occupied by crystal grains of 1 μm or more is 80% or more Therefore, it exhibits excellent chipping resistance and wear resistance in cutting of difficult-to-cut materials such as stainless steel.
On the other hand, it is apparent that the comparative coated tool in which the structure of the hard coating layer is outside the range defined in the present invention reaches the service life in a relatively short time due to occurrence of chipping or a decrease in wear resistance.

As described above, the coated tool of the present invention exhibits excellent cutting performance over a long period when subjected to cutting of difficult-to-cut materials such as stainless steel. It can fully satisfy the labor-saving and energy-saving of cutting and cost reduction.

Claims (4)

In a surface-coated cutting tool in which a hard coating layer having an average layer thickness of 2 to 10 μm is vapor-deposited on the surface of a tool base composed of a tungsten carbide-based cemented carbide,
(A) The hard coating layer is composed of a composite nitride layer of Al and Cr, and the content ratio of Cr in the total amount of Al and Cr in the layer is 0.2 to 0.5 (however, atomic ratio) And
(B) In the range from the cutting edge on the flank of the surface-coated cutting tool to a position 100 μm away, the hard coating layer has granular crystal grains having an average grain size of 0.2 to 1 μm and an average grain size of 0.08 μm or less. It has a mixed structure with fine crystal grains, and the crystal grain length ratio of the fine crystal grains with a grain size of less than 0.1 μm accounts for 10 to 50% of the mixed structure,
(C) At the interface between the tool base and the hard coating layer in the range from the cutting edge on the flank of the surface-coated cutting tool to a position 100 μm away, the crystal grain size ratio occupied by crystal grains having a grain size of 0.15 μm or less Is a surface-coated cutting tool characterized by being 20% or less.   When the edge angle of the surface-coated cutting tool is α degrees, and the occupation angle of continuous cracks formed in the hard coating layer at the corner portion of the cutting edge tip within the angle range of the α degrees is β degrees, The surface-coated cutting tool according to claim 1, wherein a crack occupancy ratio β / α is 0.3 to 1.0.   The number of continuous cracks of 80% or more of the total number of continuous cracks exists only in the hard coating layer without penetrating the hard coating layer outermost surface and the interface between the tool base and the hard coating layer, and 3. The hard coating layer having a crystal grain length ratio of 80% or more of crystal grains having a grain size of 0.1 μm or more penetrates from one end to the other end of the continuous crack. The surface-coated cutting tool described. A surface-coated cutting tool manufacturing method in which a hard coating layer having an average layer thickness of 2 to 10 μm is vapor-deposited on the surface of a tool base composed of a tungsten carbide-based cemented carbide alloy, comprising an anode electrode and an Al—Cr alloy A base body loading step in which a tool base body made of a tungsten carbide-based cemented carbide is placed in an arc ion plating apparatus including a target consisting of the above and a magnetic force generation source provided on the back side of the target; and the tool base body A vapor deposition step of vapor-depositing and forming a hard coating layer composed of a composite nitride layer of Al and Cr, the vapor deposition step comprising: a gas introduction step of introducing nitrogen gas into the arc ion plating apparatus; and the target An application step of applying a magnetic field having an integrated magnetic force within a range of 45 to 100 mT × mm by the magnetic force generation source between the tool base and the tool base; A discharge step for generating an arc discharge between the target and the anode electrode while applying a bias voltage to the target, and a rotation and revolution step for rotating and revolving the tool base in the arc ion plating apparatus. When the tool base is closest to the target, the tool base is supported such that a part or all of the flank of the tool base and the surface of the target on the tool base side are horizontal. The method for manufacturing a surface-coated cutting tool according to any one of claims 1 to 3.