JP2017159423A - Surface coated cutting tool having excellent chipping resistance and wear resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface coated cutting tool having excellent chipping resistance and wear resistance.SOLUTION: A hard coating layer includes at least an AlCrSiNiZrN layer, and the layer comprises a main phase, and a CrSi-rich particle and a NiZr-rich particle which are dispersed in the main phase. When each composition is represented by a composition formula: (AlCrSiNiZr)N(herein, all of α, β, γ, δ, and x represent an atomic ratio), α, β, γ, δ, and x in each of the main phase, the CrSi-rich particle, and the NiZr-rich particle respectively satisfy a required value, and an area ratio of the CrSi-rich particle, of which a major axis occupied in a longitudinal section of the hard coating layer is equal to or longer than 100nm, is 0.5 to 5 area%, and an area ratio of the NiZr-rich particle is 0.3 to 3 area%.SELECTED DRAWING: Figure 2

Description

  The present invention shows excellent chipping resistance and wear resistance with a hard coating layer in the intermittent cutting of hardened materials such as hardened steel in which intermittent and impact high loads act on the cutting edge. The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool) that exhibits excellent cutting performance.

Conventionally, for example, as shown in Patent Document 1, a composition formula: (Al _1-xy Cr _x Si _y ) (N _1-z C _z ) (however, 0.3 ≦ x ≦ 0.7, 0 ≦ y ≦ 0.1, 0 ≦ z ≦ 0.3), and a composite carbonitride layer or composite nitride layer having an average layer thickness of 0.5 to 8.0 μm In the surface-coated cutting tool in which a hard coating is formed, the hard coating contains particles in which 90 atomic% or more of the constituent elements are metal elements, and the particles have a cross-sectional major axis of 0.05 to 1.0 μm and are hard. The film is dispersed and distributed at a longitudinal cross-sectional area ratio of 3 to 20%, and among the particles, the constituent element contains 50 atomic% or more of Al, the aspect ratio of the vertical cross-sectional shape is 2.0 or more, and the cross-sectional major axis is The vertical cross-sectional area ratio of particles whose acute angle with the substrate surface is 45 ° or less is A%, and other particles are longitudinally cut. A coated tool that satisfies 0.3 ≦ A / (A + B) when the surface area ratio is B% and exhibits excellent chipping resistance and wear resistance in face milling of carbon steel, alloy tool steel, etc. It has been known.

  Further, as shown in Patent Document 2, surface-coated cutting in which a hard coating layer made of a composite nitride layer of Al and Cr having a layer thickness of at least 0.5 to 10 μm is formed on the surface of a tool base. In the tool, pores and particles (droplets) are dispersed and distributed in the composite nitride layer of Al and Cr, and the area ratio of the pores in any cross section of the composite nitride layer of Al and Cr and the above The occupied area ratio of the particles (droplets) is 0.5 to 1 area% and 2 to 4 area%, respectively, and among the particles (droplets), the composite nitride layer of Al and Cr Al-rich particles (droplets) having an Al content ratio higher than the average Al content are all particles in any cross-section of the composite nitride layer of Al and Cr ( Droplet) account for more than 20 area% of the area, carbon steel, in high-speed cutting, such as alloy tool steel, excellent chipping resistance, the coating tool is known to exhibit wear resistance.

Furthermore, Patent Document 3, as a target for the hard coating formed _has a composition represented by _{Cr 1-x-y-z} Al x [Ni 1-a Zr a] y M z ( where, M is At least one element selected from Ti, Nb, Si, B, W and V, 0.5 ≦ x ≦ 0.8, 0.01 ≦ y ≦ 0.35, 0 ≦ z ≦ 0.2, 51 ≦ x + y + z <1, 0.2 ≦ a ≦ 0.5), and a target having a relative density of 95% or more has been proposed, and includes a nitride, carbide or carbonitride formed using this target. It is known that a coated tool provided with a hard coating is excellent in wear resistance and adhesion.

JP 2013-56954 A JP 2012-166333 A JP 2008-238336 A

In recent years, there has been a strong demand for energy saving and energy saving in cutting, and along with this, coated tools have come to be used under more severe conditions, in order to improve chipping resistance, wear resistance, etc. The performance of the coated tool has been improved by the methods shown in Patent Documents 1 to 3, particularly in the cutting of a high hardness material in which intermittent and impact high loads act on the cutting edge. However, it cannot be said that the development of a coated tool having both characteristics of chipping resistance and wear resistance has been sufficiently developed.
For example, in the coated tool shown in Patent Document 1, 90 atomic percent or more of the elements constituting the particles contained in the hard coating are metal elements, and 50 atomic percent or more of the constituent elements are contained in Al. Therefore, the particle composition is Al-rich, the melting point is low, and the welding resistance is inferior, so that the chipping resistance is not sufficient.
Moreover, in the coated tool shown by patent document 2, the space | gap is formed in the lower part of the particle (droplet) which exists in a hard membrane | film | coat, and when the high load acts because the space | gap exists. There is a problem that the strength of the film is weak, for example, the occurrence of chipping due to the propagation and propagation of cracks in the voids.
Furthermore, the coated tool shown in Patent Document 3 is a Cr-Al-Ni-N-based hard coating, in which a part of Ni is replaced with Zr and Si as an optional component is included, thereby improving adhesion and It is intended to improve wear resistance, but when this coated tool is subjected to intermittent cutting of a hard material that is subjected to intermittent and shocking high loads on the cutting edge, chipping resistance and It was not possible to achieve both wear resistance.

  Therefore, the present invention provides excellent resistance even when subjected to intermittent cutting (for example, milling) of a hard material such as hardened steel in which intermittent and shocking high loads act on the cutting edge. An object of the present invention is to provide a coated tool that exhibits chipping and wear resistance.

  From the above-mentioned viewpoint, the present inventors have provided a hard coating layer capable of achieving both chipping resistance and wear resistance in intermittent cutting of a high-hardness material in which intermittent and impactful high loads act on the cutting edge. As a result of earnest research on the layer structure, the following findings were obtained.

  That is, in a coated tool in which a hard coating layer composed of a composite nitride layer of Al, Cr, Si, Ni, and Zr is coated on the surface of the tool base, the inside of the composite nitride layer of Al, Cr, Si, Ni, and Zr Two kinds of particles having different component systems, specifically, a CrSi rich particle and a NiZr rich particle coexist, and the two kinds of particles occupying the composite nitride layer of Al, Cr, Si, Ni and Zr. It was found that the composite nitride layer of Al, Cr, Si, Ni, and Zr exhibits excellent hardness and strength as well as welding resistance by setting the area ratio of the particules to a specific range.

The hard coating layer made of a composite nitride layer of Al, Cr, Si, Ni, and Zr can be formed on the surface of a tool base made of a tungsten carbide base cemented carbide by physical vapor deposition.
In the present invention, for example, an arc ion plating (hereinafter referred to as “AIP”) apparatus whose outline is shown in FIG. 3 is used for film formation. By controlling the strength and the magnitude of the arc current, CrSi-rich particles and NiZr-rich particles having a predetermined area ratio can be coexistingly generated in the composite nitride layer of Al, Cr, Si, Ni, and Zr.
The CrSi-rich particles having a predetermined area ratio existing in the composite nitride layer of Al, Cr, Si, Ni, and Zr contribute to the improvement of chipping resistance of the layer during cutting, and the layer It has been found that NiZr-rich particles having a predetermined area ratio existing therein contribute to improvement in lubricity.

As a result, the coated tool of the present invention in which the hard coating layer composed of the composite nitride layer of Al, Cr, Si, Ni, and Zr is formed has a high load in which intermittent and impact high loads act on the cutting edge. It exhibits excellent welding resistance, chipping resistance and wear resistance in intermittent cutting of a hard material, and exhibits excellent cutting performance over a long period of use.

The present invention has been made based on the above findings,
In a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool base made of any of tungsten carbide-based cemented carbide, TiCN-based cermet, cubic boron nitride sintered body, and high-speed tool steel,
(A) The hard coating layer includes at least a composite nitride layer of Al, Cr, Si, Ni, and Zr. The composite nitride layer includes a main phase and CrSi-rich particles dispersed and distributed in the main phase. NiZr rich particles, the composition of the main phase, CrSi rich particles and NiZr rich particles,
Composition formula: (Al1- [ _{alpha]-[beta]-[gamma]-[delta]} Cr [ _alpha] Si [ _beta] Ni [ _gamma] Zr [ _delta] ) _{1- xNx}
(Where α, β, γ, δ, and x all represent atomic ratios),
(B) The main phase is 0.15 ≦ α ≦ 0.30, 0.01 ≦ β ≦ 0.15, 0.001 ≦ γ ≦ 0.02, 0.001 ≦ δ ≦ 0.02, 45 ≦ x ≦ 0.60 is satisfied,
(C) The CrSi rich particles are 0.25 ≦ α ≦ 0.65, 0.15 ≦ β ≦ 0.50, 0 ≦ γ ≦ 0.02, 0 ≦ δ ≦ 0.02, 0.05 ≦ x. ≦ 0.35 is satisfied,
(D) The NiZr rich particles are 0 ≦ α ≦ 0.05, 0.10 ≦ β ≦ 0.25, 0.20 ≦ γ ≦ 0.40, 0.30 ≦ δ ≦ 0.45, 0.10. ≦ x ≦ 0.35 is satisfied,
(E) The occupation area ratio of the CrSi-rich particles having a major axis of 100 nm or more in the longitudinal section of the hard coating layer is 0.5 area% or more and 5 area% or less, and the longitudinal section of the hard coating layer is A surface-coated cutting tool characterized in that an occupied area ratio of the NiZr-rich particles having a major axis of 100 nm or more is 0.3 area% or more and 3 area% or less. "
It has the characteristics.

  The present invention will be described in detail below.

Hard coating layer:
As shown in the schematic diagram of FIG. 1, the hard coating layer includes at least a composite nitride layer of Al, Cr, Si, Ni, and Zr (hereinafter, referred to as “AlCrSiNiZrN”), and the layer includes the layer shown in FIG. 2) or a partially enlarged view of FIG. 2A, the main phase, and CrSi rich particles and NiZr rich particles dispersed and distributed in the main phase.

Main phase of AlCrSiNiZrN layer:
The main phase of the AlCrSiNiZrN layer is
Composition formula: (Al1- [ _{alpha]-[beta]-[gamma]-[delta]} Cr [ _alpha] Si [ _beta] Ni [ _gamma] Zr [ _delta] ) _{1- xNx}
(Where α, β, γ, δ, and x all represent atomic ratios), the constituent Al component improves high-temperature hardness and heat resistance, and the Cr component improves high-temperature strength. The Si component improves oxidation resistance. Further, the coexistence of Al and Cr has the effect of improving the high temperature oxidation resistance. Furthermore, the Ni component improves the lubricity of the layer, and the Zr component has the effect of increasing the hardness of the layer.
In the main phase, when the content ratio α of Cr in the total amount of Al, Cr, Si, Ni, and Zr is less than 0.15 (where α is an atomic ratio), the Al content is relatively high. Therefore, in milling cutting of work materials with high weldability, it is not possible to secure weld resistance to the work material and chips, and the high-temperature strength also decreases, resulting in welding and chipping. It becomes easy. On the other hand, when the content ratio α of Cr in the total amount of Al, Cr, Si, Ni and Zr exceeds 0.30, the melting point of the target material becomes high when the hard coating layer is formed by the AIP apparatus, As a result, the CrSi rich particles that are generated as a secondary matter also have a high Cr concentration and a relatively high melting point. For this reason, the shape of the CrSi-rich particles is close to a sphere, and a particle shape having a major axis of 100 nm or more is not formed, leaving a void below the particles. And this space | gap tends to become a starting point of the crack at the time of cutting, and it becomes easy to generate | occur | produce chipping.
Therefore, the content ratio α of Cr in the total amount of Al, Cr, Si, Ni, and Zr is 0.15 ≦ α ≦ 0.30.

  In addition, when the content ratio β of Si in the total amount of Al, Cr, Si, Ni, and Zr is less than 0.01, the effect of improving the oxidation resistance is small, and the Cr content ratio is relatively high. Has a high melting point and little effect of improving chipping resistance. On the other hand, if the content ratio β of Si in the total amount of Al, Cr, Si, Ni, and Zr exceeds 0.15, the high-temperature toughness and high-temperature strength of the main phase decrease, so Al, Cr, Si, and Ni The content ratio β of Si in the total amount of Zr is 0.01 ≦ β ≦ 0.15.

  Further, when the content ratio γ of Ni in the total amount of Al, Cr, Si, Ni, and Zr is less than 0.001, the effect of improving the lubricity of the main phase is small, while Al, Cr, Si, Ni, and Zr are less effective. When the content ratio γ of Ni in the total amount exceeds 0.02, the wear resistance is reduced by reducing the hardness of the main phase, so Ni in the total amount of Al, Cr, Si, Ni and Zr. Is set to 0.001 ≦ γ ≦ 0.02.

  Furthermore, when the content ratio δ of Zr in the total amount of Al, Cr, Si, Ni, and Zr is less than 0.001, there is little effect of increasing the hardness of the main phase, while Al, Cr, Si, Ni, and Zr are less effective. When the content ratio δ of Zr in the total amount exceeds 0.02, chipping resistance is lowered. Therefore, the content ratio δ of Zr in the total amount of Al, Cr, Si, Ni, and Zr is 0.001 ≦ Let γ ≦ 0.02.

  In the main phase composed of composite nitride, the content ratio x of the N component with respect to the total amount of the components constituting the main phase is not limited to the stoichiometric ratio of 0.50, and an effect equivalent to this is obtained. The range of 0.45 ≦ x ≦ 0.60, which is a range to be measured, may be used.

The layer thickness of the hard coating layer is not particularly limited in the present invention, but if the layer thickness of the hard coating layer is less than 0.5 μm, sufficient wear resistance cannot be exhibited over a long period of time, On the other hand, if it exceeds 10.0 μm, the compressive residual stress accumulated in the hard coating layer becomes large, so that chipping is likely to occur at the cutting edge in the initial stage of cutting, and the hard coating layer itself may be self-destructed. There is.
Therefore, the thickness of the hard coating layer is desirably 0.5 μm or more and 8.0 μm or less.

CrSi-rich particles and NiZr-rich particles in the hard coating layer:
In the hard coating layer, CrSi rich particles and NiZr rich particles (see FIGS. 2A and 2B) dispersed and distributed in the main phase are formed.
The generation of CrSi-rich particles and NiZr-rich particles is performed by using the AIP apparatus shown in FIG. 3 to deposit the hard coating layer, in particular, the magnetic flux density applied to the target and the arc current. By controlling, each particle can have a desired composition, and among the particles present in the hard coating layer, the area ratio of each particle having a major axis of 100 nm or more in the longitudinal section of the hard coating layer Can be set to a desired value.

CrSi rich particles:
CrSi-rich particles are dispersed and distributed in the main phase, improving the high temperature strength of the hard coating layer during cutting, and as a result, improving chipping resistance during cutting.
The composition of the CrSi rich particles
Composition formula: (Al1- [ _{alpha]-[beta]-[gamma]-[delta]} Cr [ _alpha] Si [ _beta] Ni [ _gamma] Zr [ _delta] ) _{1- xNx}
(Α, β, γ, δ, and x all represent atomic ratios), the composition of the CrSi rich particles is 0.25 ≦ α ≦ 0.65, 0.15 ≦ β ≦ 0.50, If it is outside the range of 0 ≦ γ ≦ 0.02, 0 ≦ δ ≦ 0.02, 0.05 ≦ x ≦ 0.35, in the intermittent cutting of hard materials such as hardened steel, Since it becomes impossible to ensure high temperature strength against the powder, chipping is likely to occur.
If the Cr content ratio α is less than 0.25, sufficient strength cannot be obtained with respect to the main phase, and the effect of improving chipping resistance exhibited when dispersed in the main phase becomes small. On the other hand, when the content ratio of Cr exceeds 0.65, the particles are almost spherical and voids are likely to remain under the particles, which tends to be the starting point of cracks, and chipping is likely to occur.
When the Si content ratio β is less than 0.15, the oxidation resistance of the particles decreases, and when it exceeds 0.50, the high-temperature toughness of the particles decreases, and the particles themselves become starting points of cracks.
When the content ratio of Ni and Zr exceeds 0.02, the strength of the particles themselves is lowered, and the chipping resistance obtained by dispersing the CrSi rich particles cannot be sufficiently exhibited.
When the content x of N is less than 0.05, the affinity with the main phase is lowered, and the interface between the particles and the main phase becomes the starting point of cracks. When the content exceeds 0.35, the effect as a CrSi rich particle is obtained. Is not demonstrated.

NiZr rich particles:
NiZr-rich particles are dispersed and distributed in the main phase, improving the lubricity of the hard coating layer and, as a result, improving the wear resistance.
The composition of NiZr rich particles
Composition formula: (Al1- [ _{alpha]-[beta]-[gamma]-[delta]} Cr [ _alpha] Si [ _beta] Ni [ _gamma] Zr [ _delta] ) _{1- xNx}
(Α, β, γ, δ, and x all represent atomic ratios), the composition of the NiZr rich particles is 0 ≦ α ≦ 0.05, 0.10 ≦ β ≦ 0.25, 0. If it is out of the range of 20 ≦ γ ≦ 0.40, 0.30 ≦ δ ≦ 0.45, 0.10 ≦ x ≦ 0.35, the wear resistance improving effect is lowered.
When the Ni content ratio γ is less than 0.20, the lubricity as NiZr-rich particles is not exhibited. On the other hand, when the Ni content ratio γ exceeds 0.40, the hardness of the particles is reduced and these particles are dispersed. This reduces the hardness of the entire film and reduces the wear resistance.
When the content ratio δ of Zr is less than 0.30, the hardness of the particles decreases, the particle part is easily damaged locally, and becomes a starting point of damage to the entire film. On the other hand, when the content ratio of Zr exceeds 0.045, the shape of the particles is relatively close to a sphere, and voids are likely to remain under the particles, which tends to be the starting point of cracks, and chipping is likely to occur.
When the Cr content ratio α exceeds 0.05, the hardness of the particles is relatively lowered and the wear resistance is lowered.
When the Si content ratio β is less than 0.10, the oxidation resistance of the particles is not exhibited. When the Si content ratio β exceeds 0.25, the toughness is lowered, and the particle portion tends to be a starting point of damage, and chipping is likely to occur.
When the content x of N is less than 0.10, the affinity with the main phase is lowered, and the interface between the particle and the main phase becomes the starting point of cracks. When the content exceeds 0.35, the effect as NiZr rich particles is obtained. Is not demonstrated.

The composition of CrSi-rich particles and NiZr-rich particles dispersed and distributed in the main phase can be measured using a scanning electron microscope-energy dispersive X-ray spectroscopic analysis (SEM-EDS).

In the present invention, the hard coating layer includes at least an AlCrSiNiZrN layer, and the hard coating layer is excellent by configuring the layer with a main phase and CrSi rich particles and NiZr rich particles dispersed and distributed in the main phase. Although it has welding resistance, chipping resistance, and wear resistance, the characteristics of the hard coating layer are affected by the area ratio of CrSi-rich particles and NiZr-rich particles present in the hard coating layer. It is important to maintain the area ratio of the particles in the coating layer within an appropriate range.
The hard coating layer of the present invention is mainly deposited by using an AIP apparatus and under controlled film forming conditions (particularly, the strength of magnetic flux density applied to the target and the magnitude of arc current). At the same time as the phase is formed, CrSi-rich particles and NiZr-rich particles are distributed and formed in the main phase.
When the longitudinal section of the hard coating layer is observed, the particles are formed as a flat shape having a diameter in a direction substantially parallel to the tool base surface. When the aspect ratio is measured from the ratio of the major axis to the minor axis and the average is obtained, it is 2 or more.
When the aspect ratio of the particles is less than 2, the particle shape is nearly spherical and voids are likely to be generated under the particles, and these voids are likely to become the starting point of cracks and cause chipping.
Among the above particles, the presence of particles having a major axis of 100 nm or more affects the characteristics of the hard coating layer. Therefore, the CrSi-rich particles having a major axis of 100 nm or more occupy the vertical section of the hard coating layer. The ratio is 0.5 area% or more and 5 area% or less, and for the NiZr rich particles, the area ratio in the longitudinal section of the hard coating layer is 0.3 area% or more and 3 area% or less.
If the area ratio of CrSi rich particles is less than 0.5 area%, sufficient chipping resistance cannot be exhibited. On the other hand, when the area ratio of the CrSi rich particles exceeds 5 area%, the hardness of the entire film is reduced.
Moreover, when the area ratio of NiZr rich particles is less than 0.3 area%, sufficient lubricity cannot be exhibited. On the other hand, when the area ratio of the NiZr-rich particles exceeds 3 area%, the hardness of the entire film is lowered and the wear resistance is lowered.

The major axis of the particle means the longest diameter measured with respect to the cross-sectional shape of the particle in the cross section of the hard coating layer perpendicular to the surface of the base. In the present invention, the major axis of almost all particles is parallel to the surface of the tool base. Therefore, the maximum particle length measured in the direction parallel to the tool base surface is called the major axis, and the maximum length of the particles perpendicular to the major axis direction is called the minor axis.
The aspect ratio is a value of major axis / minor axis, and the average aspect ratio is a value obtained by measuring the aspect ratio at a plurality of locations and averaging the measured values.

In the coated tool of the present invention, the hard coating layer includes at least an AlCrSiNiZrN layer, and the layer is composed of a main phase, and CrSi-rich particles and NiZr-rich particles dispersed and distributed in the main phase. Composition formula: (Al _{1-α-β-γ-δ} Cr _α Si _β Ni _γ Zr _δ ) _1-x N _x (where α, β, γ, δ, x are atomic ratios) Main phase is 0.15 ≦ α ≦ 0.30, 0.01 ≦ β ≦ 0.15, 0.001 ≦ γ ≦ 0.02, 0.001 ≦ γ ≦ 0.02, 0.45 ≦ x ≦ 0.60, CrSi rich particles are 0.25 ≦ α ≦ 0.65, 0.15 ≦ β ≦ 0.50, 0 ≦ γ ≦ 0.02, 0 ≦ δ ≦ 0.02. 0.05 ≦ x ≦ 0.35, and NiZr rich particles satisfy 0 ≦ α ≦ 0.05, 0.1 A hard coating layer having a composition satisfying 0 ≦ β ≦ 0.25, 0.20 ≦ γ ≦ 0.40, 0.30 ≦ δ ≦ 0.45, and 0.10 ≦ x ≦ 0.35 The occupied area ratio of CrSi-rich particles having a major axis of 100 nm or more in the longitudinal section of is 0.5 area% or more and 5 area% or less, and the occupied area ratio of NiZr-rich particles is 0.3 area% or more and 3 area%. Since it is the following, the hard coating layer of this invention is excellent in welding resistance, chipping resistance, and abrasion resistance.
Therefore, when the coated tool of the present invention is used for intermittent cutting of a hard material with a high load acting intermittently and shockingly on the cutting edge, it has excellent chipping resistance and wear resistance over a long period of use. Demonstrate.

The schematic longitudinal cross-sectional schematic diagram of the hard coating layer of this invention coated tool is shown. (A) shows the TEM image of the hard coating layer of this invention coated tool, (b) shows the elements on larger scale of (a). The schematic explanatory drawing of the arc ion plating apparatus which forms the hard coating layer of this invention coated tool is shown, (a) is a top view, (b) shows a side view.

Next, the coated tool of the present invention will be specifically described with reference to examples.
In the following examples, the case where the coated tool of the present invention is used in milling will be described, but this does not exclude the use of turning, drilling, and the like.
Although the case where a WC-based cemented carbide is used as a tool base will be described, the same applies to the case where a TiCN-based cermet, a cubic boron nitride sintered body, and a high-speed tool steel are used as a tool base.
In the following examples, the case where the hard coating layer is a single layer of the AlCrSiNiZrN layer will be described. However, as the hard coating layer, it is sufficient that there is at least one AlCrSiNiZrN layer. For example, the presence of other layers such as a TiAlN layer and an AlCrCN layer is not excluded. Even if a layer other than the AlCrSiNiZrN layer is present, the operational effects of the present invention are not impaired.

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 1, 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. The green compacts were press-molded, and these green compacts were heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of temperature increase of 7 ° C./min in a 6 Pa vacuum atmosphere. After holding at temperature for 1 hour, sintering under furnace cooling conditions Then, a round sintered body for forming a tool base having a diameter of 8 mm is formed, and further, the diameter x length of the cutting edge portion is 6 mm x 13 mm and twisted by grinding from the round bar sintered body. WC-base cemented carbide tool bases (end mills) A to E each having a two-blade ball shape with an angle of 30 degrees were manufactured.

  Next, these tool bases A to E are charged into the AIP apparatus shown in FIG. 3 and subjected to Ti bombardment. Then, using a target having a predetermined component composition, a predetermined layer is formed under the film formation conditions shown in Table 2. The present coated tools 1 to 10 made of the main phase of the component composition shown in Table 3 and the CrSi rich particles and NiZr rich particles of the component composition shown in Table 4 were produced by vapor-depositing a thick hard coating layer.

For the hard coating layers of the inventive coated tools 1 to 10, the structure observation and composition analysis of the cross section of the hard coating layer perpendicular to the surface of the tool substrate were performed, and the transmission electron microscope-energy dispersive X-ray spectroscopic analysis (TEM-EDS) was performed. Used.
The observation range of the coated tool of the present invention is 20 μm in the direction parallel to the surface of the tool substrate, and element mapping with a spatial resolution of 0.01 μm or less is performed on the cross section of the hard coating layer, the main phase of the coated hard coating layer and the CrSi rich The composition of the particles and the NiZr rich particles was measured at a plurality of locations and confirmed to be within the range defined by the present invention.
Moreover, the area ratio which CrSi rich particle and NiZr rich particle occupy in a hard coating layer cross section calculated | required with the following method. That is, in the TEM-EDS mapping image obtained by photographing each particle, the boundary between the particle and the main phase is distinguished using the mapping image obtained by analyzing the nitrogen amount, and the outer periphery of the particle having a major axis of 100 nm or more is selected and surrounded. The obtained area was calculated using image analysis software (for example, Adobe photoshop), and was calculated as the area ratio of particles in the cross section of the hard coating layer in the measurement region.
Next, the maximum length of the CrSi-rich particles and NiZr-rich particles in the direction parallel to the tool base surface is measured as the major axis, and the maximum length in the direction perpendicular to the major axis direction is measured as the minor axis. The average aspect ratio of the particles was calculated by calculating the aspect ratio (major axis / minor axis) of the particles, measuring the aspect ratio in a plurality of regions, and averaging these values.
Tables 3 and 4 show these measured values and calculated values, respectively.

  Next, for the purpose of comparison, Ti bombarding is performed on the surfaces of the tool bases A to E using the AIP apparatus, and then using the targets having a predetermined component composition, the film forming conditions shown in Table 5 are: By forming various hard coating layers by vapor deposition, comparative coated tools 1 to 10 composed of the main phase of the component composition shown in Table 6 and the CrSi rich particles and NiZr rich particles of the component composition shown in Table 7 were produced.

As for the comparative coated tools 1 to 10, the cross section is observed by TEM-EDS, and the composition of the main phase constituting the hard coating layer by the point analysis in the hard coating layer cross section, and the composition when particles are present. In addition, the area ratio of particles in the cross section of the hard coating layer and the average aspect ratio of the particles were calculated.
Tables 6 and 7 show these values, respectively.

Moreover, the layer thickness of the hard coating layer of this invention coated tool 1-10 and comparative coated tool 1-10 was measured using the scanning electron microscope (SEM).
Tables 3 and 6 show these values.

Next, a milling cutting test was performed on the present coated tools 1 to 10 and comparative coated tools 1 to 10 under the following conditions, and the flank wear width of the cutting edge was measured.
Work material: Block material of JIS / SKH51 (HRC64)
Rotational speed: 5400 / min. ,
Cutting speed: 100 m / min. ,
Cutting depth: ae 0.2mm, ap 2.0mm
Feed (per blade): 0.05mm / tooth,
Cutting fluid: air blow,
Cutting length: 20 m
Table 8 shows the results of the cutting test and the presence or absence of chipping.

From the results shown in Tables 3, 4, 6, 7, and 8, the coated tools 1 to 10 of the present invention have a CrSi-rich particle having a predetermined composition together with a main phase having a predetermined composition in a hard coating layer composed of an AlCrSiNiZrN layer. In addition, the presence of NiZr-rich particles at a predetermined area ratio showed excellent chipping resistance and wear resistance in intermittent cutting of a high hardness material in which intermittent and impact high loads act on the cutting edge.
In contrast, the comparative coated tools 1 to 10 are
Although particles are formed in the hard coating layer, they are outside the range defined by the present invention, and thus cannot be said to be excellent in both chipping resistance and wear resistance.

  The coated tool of the present invention exhibits excellent chipping resistance and wear resistance in intermittent cutting of hard materials such as hardened steel, and can extend the service life. Of course, it is also possible to use it in cutting of a cutting material or cutting under other conditions.

Claims (1)

In a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool base made of any of tungsten carbide-based cemented carbide, TiCN-based cermet, cubic boron nitride sintered body, and high-speed tool steel,
(A) The hard coating layer includes at least a composite nitride layer of Al, Cr, Si, Ni, and Zr. The composite nitride layer includes a main phase and CrSi-rich particles dispersed and distributed in the main phase. NiZr rich particles, the composition of the main phase, CrSi rich particles and NiZr rich particles,
Composition formula: (Al1- [ _{alpha]-[beta]-[gamma]-[delta]} Cr [ _alpha] Si [ _beta] Ni [ _gamma] Zr [ _delta] ) _{1- xNx}
(Where α, β, γ, δ, and x all represent atomic ratios),
(B) The main phase is 0.15 ≦ α ≦ 0.30, 0.01 ≦ β ≦ 0.15, 0.001 ≦ γ ≦ 0.02, 0.001 ≦ δ ≦ 0.02, 45 ≦ x ≦ 0.60 is satisfied,
(C) The CrSi rich particles are 0.25 ≦ α ≦ 0.65, 0.15 ≦ β ≦ 0.50, 0 ≦ γ ≦ 0.02, 0 ≦ δ ≦ 0.02, 0.05 ≦ x. ≦ 0.35 is satisfied,
(D) The NiZr rich particles are 0 ≦ α ≦ 0.05, 0.10 ≦ β ≦ 0.25, 0.20 ≦ γ ≦ 0.40, 0.30 ≦ δ ≦ 0.45, 0.10. ≦ x ≦ 0.35 is satisfied,
(E) The occupation area ratio of the CrSi-rich particles having a major axis of 100 nm or more in the longitudinal section of the hard coating layer is 0.5 area% or more and 5 area% or less, and the longitudinal section of the hard coating layer is A surface-coated cutting tool characterized in that an occupied area ratio of the NiZr-rich particles having a major axis of 100 nm or more is 0.3 area% or more and 3 area% or less.