WO2017073787A1 - Surface-coated cutting tool, and production method therefor - Google Patents

Abstract

In this coated tool, a hard coating layer (2) includes at least a layer (3) of a composite nitride or composite carbonitride represented by the compositional formula (Cr_1-xAl_x)(C_yN_1-y), or a layer (3) of a composite nitride or composite carbonitride represented by the compositional formula (Ti_1-α-βAl_αMe_β)(C_γN_1-γ). Crystal grains which form the layer (3) of the composite nitride or composite carbonitride include crystal grains which have an NaCl-type face-centered cubic structure. Crystal grains having an average crystal grain orientation spread (GOS) of at least 2˚ among the crystal grains having the NaCl-type face-centered cubic structure account for at least 40% by area ratio of the total area of the layer (3) of the composite nitride or composite carbonitride.

Description

Surface-coated cutting tool and manufacturing method thereof

The present invention has high heat generation such as carbon steel, alloy steel, cast iron and the like, and has high chipping resistance with a hard coating layer in high-speed intermittent cutting processing in which an impact load is applied to the cutting edge. The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool) that exhibits excellent wear resistance over a long period of use and a method for producing the surface-coated cutting tool.
The present application is based on Japanese Patent Application Nos. 2015-214522 and 2015-214528 filed in Japan on October 30, 2015, and Japanese Patent Application No. 2016-212416 filed in Japan on October 28, 2016. Claim the right and use it here.

Conventionally, generally composed of tungsten carbide (hereinafter referred to as WC) based cemented carbide, titanium carbonitride (hereinafter referred to as TiCN) based cermet or cubic boron nitride (hereinafter referred to as cBN) based ultra high pressure sintered body A coated tool in which a Cr—Al-based or Ti—Al-based composite nitride layer is coated as a hard coating layer on the surface of a tool base (hereinafter collectively referred to as a tool base) by physical vapor deposition. These are known and are known to exhibit excellent wear resistance.
However, the above-mentioned coated tools coated with the conventional Cr-Al or Ti-Al composite nitride layer have relatively high wear resistance, but abnormalities such as chipping when used under high-speed interrupted cutting conditions. Various proposals for improvement of the hard coating layer have been made because of easy wear.

For example, Patent Document 1 discloses a hard coating composed of a lower layer, an intermediate layer, and an upper layer on the surface of a tool base in order to improve chipping resistance and wear resistance in high-speed intermittent cutting such as stainless steel and Ti alloy. The lower layer has a predetermined average layer thickness, and includes a Ti _1-X Al _X N layer, a Ti _1-X Al _X C layer, a Ti _1-X Al _X CN layer (X is Al The content ratio (atomic ratio) of 0.65 ≦ X ≦ 0.95) is composed of a TiAl compound having a cubic structure consisting of one or more layers, and the intermediate layer has a predetermined average layer thickness. And a Cr _1-Y Al _Y N layer, a Cr _1-Y Al _Y C layer, a Cr _1-Y Al _Y CN layer (Y is the Al content (atomic ratio), and 0.60 ≦ Y ≦ 0.90) CrAl having a cubic structure consisting of one or more layers Composed of objects, improving the upper layer, by configuring in Al ₂ O ₃ having a predetermined average thickness, to improve the adhesion strength of the lower layer and the upper layer, thereby, the chipping resistance and abrasion resistance It has been proposed to let

Patent Document 2 discloses that a lower layer, an intermediate layer, and an upper layer are formed on the surface of a tool base in order to improve chipping resistance and wear resistance in high-speed intermittent cutting of a heat-resistant alloy such as precipitation hardened stainless steel and Inconel. And a lower layer is a Ti _1-X Al _X N layer, a Ti _1-X Al _X C layer, a Ti _1-X Al _X CN layer (X is Al The atomic ratio is 0.65 ≦ X ≦ 0.95) and is composed of a Ti compound having a cubic crystal structure consisting of one layer or two or more layers, and the intermediate layer is a predetermined single layer average layer Thick Cr _1-Y Al _Y N layer, Cr _1-Y Al _Y C layer, Cr _1-Y Al _Y CN layer (Y represents the Al content and represents the atomic ratio, 0.60 ≦ Y ≦ 0. 90) having a cubic crystal structure consisting of one or more layers. constituted by r compound, by the upper layer composed of Al ₂ O ₃ with an average layer thickness with a predetermined pore size and pore density micro pores of, improves the adhesion strength of the lower layer and the upper layer The upper layer is made of an Al ₂ O ₃ layer having micropores having a predetermined pore diameter and pore density, thereby reducing mechanical and thermal shocks, thereby improving chipping resistance and wear resistance. It has been proposed.

Further, in Patent Document 3, in order to improve the fracture resistance of the hard coating layer in heavy cutting of steel or cast iron in which a high load acts on the cutting edge, (Al _1-X Cr _X ) N (where X is an atomic ratio, X = 0.3 to 0.6) is provided with a hard coating layer, and the normal of the {100} plane with respect to the normal of the surface polished surface of the tool substrate In the inclination angle frequency distribution graph created by measuring the inclination angle formed by, the highest peak exists in the inclination angle section of 30 to 40 degrees, the total frequency is 60% or more of the whole, and the surface polished surface In the constituent atomic shared lattice distribution graph created by measuring the inclination angle formed by the normal of the {112} plane with respect to the normal of Σ3, the highest peak exists at Σ3, and the distribution ratio is 50% or more of the whole By forming the crystal orientation and constituent atomic shared lattice distribution form (Al _{1-X Cr X)} to improve the high temperature strength of the _N layer, has been, it has been proposed to improve the fracture resistance of the hard coating layer in the heavy cutting.

Patent Document 4 discloses a surface-coated cutting tool including a tool base and a hard coating layer formed on the base, and the hard coating layer includes one or both of Al and Cr. A compound composed of at least one element selected from the group consisting of Group 4a, 5a, 6a group elements and Si, and at least one element selected from the group consisting of carbon, nitrogen, oxygen and boron And chlorine are disclosed to dramatically improve the wear resistance and oxidation resistance of the hard coating layer.

Further, for example, Patent Document 5 discloses that the value of the Al content ratio x is 0. by performing chemical vapor deposition in a temperature range of 650 to 900 ° C. in a mixed reaction gas of TiCl ₄ , AlCl ₃ , and NH ₃ . It is described that a (Ti _1-x Al _x ) N layer having a thickness of 65 to 0.95 can be formed by vapor deposition. In this document, an Al ₂ O layer is further formed on the (Ti _1-x Al _x ) N layer. _The formation of a (Ti _1-x Al _x ) N layer with the aim of covering _three layers and thereby increasing the thermal insulation effect, with the value of x increased from 0.65 to 0.95, There is no disclosure up to what point it has on cutting performance.

Further, in Patent Document 6, a TiCN layer and an Al ₂ O ₃ layer are used as inner layers, and a cubic crystal structure (Ti _1-x) including a cubic crystal structure or a hexagonal crystal structure is formed thereon by chemical vapor deposition. Al _x ) N layer (where x is 0.65 to 0.9) is coated as an outer layer, and by applying compressive stress of 100 to 1100 MPa to the outer layer, the heat resistance and fatigue strength of the coated tool are improved. It has been proposed to do.

Japanese Unexamined Patent Publication No. 2014-208394 (A) Japanese Unexamined Patent Publication No. 2014-198362 (A) Japanese Unexamined Patent Publication No. 2009-56539 (A) Japanese Unexamined Patent Publication No. 2006-82207 (A) Japan Special Table 2011-516722 Publication (A) Japanese National Table 2011-513594 (A)

In recent years, there has been a strong demand for energy saving and energy saving in cutting, and along with this, cutting tends to be faster and more efficient, and the coated tool has even more chipping resistance, chipping resistance, Abnormal damage resistance such as peel resistance is required, and excellent wear resistance over long-term use is required.
However, the coated tools described in Patent Documents 1 and 2 improve the adhesion strength between the lower layer and the upper layer by interposing and forming a CrAl compound and a Cr compound as an intermediate layer of the hard coating layer. Although the chipping property is improved, the strength and hardness of the CrAl compound and the Cr compound itself are not sufficient, so that when used for high-speed intermittent cutting, the chipping resistance and wear resistance are sufficient. I can't say that.
In the coated tool described in Patent Document 3, the Cr content ratio of the hard coating layer made of (Al _1-X Cr _X ) N is adjusted, and the crystal orientation and constituent atomic shared lattice point distribution are adjusted. By controlling the form, the strength of the hard coating layer can be improved, and as a result, the chipping resistance and chipping resistance can be improved, but the strength of the (Al _1-X Cr _X ) N layer Since the hardness is not sufficient, excellent chipping resistance and wear resistance cannot be exhibited over a long period of use, and there is a problem that the tool life is short in high-speed intermittent cutting of alloy steel.
Further, the coated tool described in Patent Document 4 is intended to improve wear resistance and oxidation resistance, but it is resistant to chipping under cutting conditions such as high-speed interrupted cutting. There was a problem that the sex was not enough.
In addition, for the (Ti _1-x Al _x ) N layer formed by chemical vapor deposition described in Patent Document 5, the Al content ratio x can be increased and a cubic structure can be formed. Therefore, although a hard coating layer having a predetermined hardness and excellent wear resistance can be obtained, there is a problem that the toughness is inferior.
Furthermore, although the coated tool described in Patent Document 6 has a predetermined hardness and excellent wear resistance, it is inferior in toughness, so when it is used for high-speed intermittent cutting of alloy steel, etc. However, there is a problem that abnormal damage such as chipping, chipping and peeling is likely to occur, and it cannot be said that satisfactory cutting performance is exhibited.
Therefore, with high heat generation such as carbon steel, alloy steel, cast iron, etc., high-speed intermittent cutting with impact load on the cutting blade, chipping resistance with excellent hard coating layer, excellent wear resistance There is a need for a coated tool having both

In view of the above, the present inventors have at least a composite nitride or composite carbonitride of Cr and Al (hereinafter referred to as “(Cr, Al) (C, N)” or “(Cr _1-x Al _x ) (which may be represented by (C _y N _1-y ))), and a coated nitride or composite carbonitride of at least Ti and Al (hereinafter, Chipping resistance of a coated tool provided with a hard coating layer containing “(Ti, Al) (C, N)” or “(Ti _1−α Al _α ) (may be represented by C _γ N _1−γ )” As a result of intensive studies to improve the wear resistance and wear resistance, the following findings were obtained.

That is, it includes at least one conventional (Cr _1−x Al _x ) (C _y N _1−y ) layer or (Ti _1−α Al _α ) (C _γ N _1−γ ) layer and has a predetermined The hard coating layer having an average layer thickness of (Cr _1−x Al _x ) (C _y N _1−y ) layer or (Ti _1−α Al _α ) (C _γ N _1−γ ) layer is a tool. When it is formed in a columnar shape in the vertical direction on the substrate, it has high wear resistance. On the other hand, as the anisotropy of the (Cr _1−x Al _x ) (C _y N _1−y ) layer or (Ti _1−α Al _α ) (C _γ N _1−γ ) layer increases, (Cr _{1 -X} Al _x ) (C _y N _1-y ) layer or (Ti _1-α Al _α ) (C _γ N _1-γ ) layer has decreased toughness, resulting in chipping resistance and chipping resistance. As a result, the wear resistance could not be exhibited over a long period of use, and the tool life was not satisfactory.
Accordingly, the present inventors, constituting the hard layer _{(Cr 1-x Al x)} (C y N 1-y) layer, _{and, (Ti 1-α Al α} ) (C γ N 1-γ) As a result of intensive research on the layers, it was found that the (Cr _1-x Al _x ) (C _y N _1-y ) layer and the (Ti _1-α Al _α ) (C _γ N _1-γ ) layer have Si, Zr, B (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) layer containing a kind of element selected from V, Cr and the like (hereinafter referred to as “Me”) is NaCl type. Including crystal grains having a face-centered cubic structure (hereinafter, sometimes simply referred to as “cubic structure”), and the average orientation difference within the crystal grains of the crystal grains having the cubic structure is at least 2 degrees. Through a new concept, we succeeded in producing strain in the crystal grains having a cubic structure and increasing both hardness and toughness. _Fruit, in _{(Cr 1-x Al x)} (C y N 1-y) layer, found a novel finding that can with chipping resistance of the hard coating layer to improve the wear resistance, also, (Ti _{In the 1-α-β} Al _α Me _β ) (C _γ N _1-γ ) layer, a novel finding has been found that the chipping resistance and fracture resistance of the hard coating layer can be improved.

In particular,
(1) The hard coating layer includes at least a composite nitride or composite carbonitride layer of Cr and Al, and the layer has a composition formula: (Cr _1−x Al _x ) (C _y N _{1 − y} ), in particular, the average content ratio x _avg in the total amount of Cr and Al in Al and the average content ratio y _avg in the total amount of C and N in C (where x _avg and y _avg are either Also satisfy 0.70 ≦ x _avg ≦ 0.95 and 0 ≦ y _avg ≦ 0.005, respectively, and have a cubic structure in the crystal grains constituting the composite nitride or composite carbonitride layer. When the crystal orientation of the crystal grain is analyzed from the longitudinal cross-sectional direction using an electron beam backscattering diffractometer, and the average orientation difference within the crystal grain is obtained, the average orientation within the crystal grain The crystal grains showing the difference of 2 degrees or more are 40 in terms of the area ratio of the composite nitride or composite carbonitride layer. The presence or causes a distortion in the crystal grains having a cubic structure, as compared with the conventional hard coating _{layer, (Cr 1-x Al x} ) Hardness of (C _{y N 1-y)} layer and toughness As a result, it has been found that wear resistance is improved together with chipping resistance,
(2) The hard coating layer is a composite nitride or composite carbonitride layer of Ti, Al, and Me (where Me is a kind of element selected from Si, Zr, B, V, and Cr). In particular, when represented by the composition formula: (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ), the average content ratio α _avg in the total amount of Ti, Al and Me in Al And the average content ratio β _avg in the total amount of Ti, Al, and Me in Me and the average content ratio γ _avg in the total amount of C and N in C (where α _avg , β _avg , and γ _avg are all atomic ratios) ) Satisfy 0.60 ≦ α _avg , 0.005 ≦ β _avg ≦ 0.10, 0 ≦ γ _avg ≦ 0.005, 0.605 ≦ α _avg + β _avg ≦ 0.95, respectively. Cubic structure in the crystal grains constituting the oxide or composite carbonitride layer When the crystal orientation of the crystal grain is analyzed from the longitudinal cross-sectional direction using an electron beam backscattering diffractometer, and the average orientation difference within the crystal grain is obtained, the average orientation within the crystal grain Crystal grains having a difference of 2 degrees or more are present in the composite nitride or composite carbonitride layer in an area ratio of 40% or more, causing distortion in the crystal grains having a cubic structure, and in the conventional hard coating layer. In comparison, the hardness and toughness of the (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) layer are increased, and as a result, chipping resistance and fracture resistance are improved. It has been found that it exhibits excellent wear resistance.

The (Cr _1−x Al _x ) (C _y N _1−y ) layer and the (Ti _1−α−β Al _α Me _β ) (C _γ N _1−γ ) layer configured as described above are For example, the film can be formed by the following chemical vapor deposition method in which the reaction gas composition is periodically changed on the tool substrate surface.

(1) Regarding the (Cr _1-x Al _x ) (C _y N _1-y ) Layer The chemical vapor deposition reactor used includes a gas group A composed of NH ₃ and H ₂ , CrCl ₃ , AlCl ₃ , Al (CH ₃ ) A gas group B composed of ₃ , N ₂ and H ₂ is supplied into the reactor from the separate gas supply pipes, and the supply of the gas group A and the gas group B into the reactor is, for example, at a constant cycle. In such a time interval, the gas is supplied so that the gas flows for a time shorter than the period, and the gas supply of the gas group A and the gas group B has a phase difference shorter than the gas supply time. The reaction gas composition on the surface can be changed temporally with (a) gas group A, (b) mixed gas of gas group A and gas group B, and (c) gas group B. Incidentally, in the present invention, it is not necessary to introduce a long exhaust process intended for strict gas replacement. Therefore, as the gas supply method, for example, the gas supply port is rotated, the tool base is rotated, or the tool base is reciprocated to change the reaction gas composition on the tool base surface. (B) a mixed gas of the gas group A and the gas group B, and (c) a mixed gas mainly of the gas group B.
The reaction gas composition (volume% with respect to the total of the gas group A and the gas group B) on the surface of the tool base is, for example, NH ₃ : 2.0 to 3.0% and H ₂ : 65 to 75 as the gas group A. %, AlCl ₃ : 0.6 to 0.9% as gas group B, CrCl ₃ : 0.2 to 0.3%, Al (CH ₃ ) ₃ : 0 to 0.5%, N ₂ : 12.5 ∼15.0%, H ₂ : remaining, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 750 to 900 ° C, supply cycle 1 to 5 seconds, gas supply time per cycle 0.15 to By performing the thermal CVD method for a predetermined time with a phase difference of 0.10 to 0.20 seconds for the supply of the gas group A and the gas group B for 0.25 seconds, (Cr _1-x Al _x ) (C _y N _1-y ) layer is formed.

Then, as described above, by supplying the gas group A and the gas group B so that there is a difference in the time for the gas group B to reach the surface of the tool base, local compositional unevenness in the crystal grains, dislocations and point defects are introduced. Local distortion of the crystal lattice is formed, resulting in improved hardness, resulting in improved wear resistance, especially high-speed interrupting of alloy steel etc. with intermittent and impact loads on the cutting edge It has been found that even when subjected to cutting, the hard coating layer can exhibit excellent cutting performance over a long period of use.

(2) (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) Layer The chemical vapor deposition reactor used includes a gas group A composed of NH ₃ and H ₂ , TiCl ₄ , Al ( A gas group B consisting of CH ₃ ) ₃ , AlCl ₃ , MeCl _n (Me chloride), N ₂ , and H ₂ is supplied into the reactor through a separate gas supply pipe. The supply into the reactor is, for example, such that the gas flows at a constant cycle time interval for a time shorter than the cycle, and the gas supply for the gas group A and the gas group B is more than the gas supply time. The reaction gas composition on the surface of the tool base is changed to gas group A (first reaction gas), gas mixture of gas group A and gas group B (second reaction gas), gas group B so that a phase difference of a short time occurs. (Third reaction gas) and time can be changed. Incidentally, in the present invention, it is not necessary to introduce a long exhaust process intended for strict gas replacement. Therefore, as a gas supply method, for example, the gas supply port is rotated, the tool base is rotated, the tool base is reciprocated, the reaction gas composition on the surface of the tool base is changed to the gas group A as the main. The gas mixture (first reaction gas), the gas mixture of gas group A and gas group B (second reaction gas), and the gas mixture mainly consisting of gas group B (third reaction gas) can be changed over time. It can be realized.
The reaction gas composition (volume% with respect to the total of the gas group A and the gas group B) on the surface of the tool base is, for example, NH ₃ : 2.0 to 3.0% and H ₂ : 65 to 75 as the gas group A. %, As gas group B, AlCl ₃ : 0.6 to 0.9%, TiCl ₄ : 0.2 to 0.3%, MeCl _n (Me chloride): 0.1 to 0.2%, Al ( CH ₃ ) ₃ : 0 to 0.5%, N ₂ : 12.5 to 15.0%, H ₂ : remaining, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 700 to 900 ° C, Supply period 1 to 5 seconds, gas supply time per cycle 0.15 to 0.25 seconds, phase difference 0.10 to 0.20 seconds of supply of gas group A and gas group B, predetermined time, thermal CVD by performing law, to deposit a predetermined target layer thickness of _{(Ti 1-α-β Al} α Me β) (C γ N 1-γ) layer The

Then, as described above, by supplying the gas group A and the gas group B so that there is a difference in the time for the gas group B to reach the surface of the tool base, local compositional unevenness in the crystal grains, dislocations and point defects are introduced. It has been found that local distortion of the crystal lattice is formed, and as a result, the toughness is dramatically improved. As a result, especially when used for high-speed intermittent cutting of alloy steel, etc., where the chipping resistance and chipping resistance are improved, and the intermittent and impact loads are applied to the cutting edge, It has been found that excellent cutting performance can be exhibited over use.

The present invention has been made based on the above findings,
“(1) Surface coating in which a hard coating layer is formed on the surface of a tool base made of any of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, and cubic boron nitride-based ultrahigh-pressure sintered body In cutting tools,
(A) The hard coating layer is a composite nitride or composite carbonitride layer of Cr and Al having an average layer thickness of 1 to 20 μm, or Ti, Al and Me (where Me is Si, Zr, B, V , A compound nitride of at least one element selected from Cr) or a composite carbonitride layer,
(B) The composite nitride or composite carbonitride layer includes at least a composite nitride or composite carbonitride phase having a NaCl-type face-centered cubic structure,
(C) The crystal orientation of the crystal grains of the composite nitride or the composite carbonitride having a NaCl-type face-centered cubic structure among the crystal grains constituting the composite nitride or the composite carbonitride layer is determined by electron beam backscattering. When analyzing from the longitudinal section direction using a diffractometer and obtaining the average orientation difference within each crystal grain, the crystal grains exhibiting an average orientation difference within the crystal grain of 2 degrees or more are complex nitride or composite carbon. A surface-coated cutting tool characterized by being present in an area ratio of 40% or more with respect to the total area of the nitride layer.
(2) The composite nitride or composite carbonitride layer is a composite nitride or composite carbonitride layer of Cr and Al, the composition of which is
Composition formula: (Cr _1-x Al _x ) (C _y N _1-y )
In the composite nitride or composite carbonitride layer, the average content ratio x _avg in the total amount of Cr and Al in Al and the average content ratio y _avg in the total amount of C and N in C (where x _avg and y _avg are both atomic ratios) satisfying 0.70 ≦ x _avg ≦ 0.95 and 0 ≦ y _avg ≦ 0.005, respectively. tool.
(3) The composite nitride or composite carbonitride layer is composed of Ti, Al, and Me (where Me is a kind of element selected from Si, Zr, B, V, and Cr). A carbonitride layer, the composition of which is
When represented by the composition formula: (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ), it occupies the total amount of Ti, Al and Me in the composite nitride or composite carbonitride layer. The average content ratio α _avg , the average content ratio β _avg in the total amount of Me Ti, Al and Me, and the average content ratio γ _avg in the total amount of C and N in C (where α _avg , β _avg , γ _avg Are atomic ratios) of 0.60 ≦ α _avg , 0.005 ≦ β _avg ≦ 0.10, 0 ≦ γ _avg ≦ 0.005, 0.605 ≦ α _avg + β _avg ≦ 0.95, respectively. The surface-coated cutting tool according to (1), wherein the surface-coated cutting tool is satisfied.
(4) The composite nitride or composite carbonitride layer is composed of a single phase of composite nitride or composite carbonitride having a NaCl-type face-centered cubic structure. (1) to (3) The surface coating cutting tool in any one.
(5) The composite nitride or composite carbonitride layer includes at least 70 area% or more of a composite nitride or composite carbonitride phase having a NaCl-type face-centered cubic structure. The surface-coated cutting tool according to any one of (3).
(6) Between the tool base and the composite nitride or composite carbonitride layer, one of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride oxide layer or The surface-coated cutting tool according to any one of (1) to (5), wherein a lower layer is formed of two or more Ti compound layers and has a total average layer thickness of 0.1 to 20 μm.
(7) An upper layer including at least an aluminum oxide layer is formed on the composite nitride or composite carbonitride layer with a total average layer thickness of 1 to 25 μm. (1) to (6) The surface-coated cutting tool according to any one of 1).
(8) The composite nitride or the composite carbonitride layer is formed by a chemical vapor deposition method containing at least trimethylaluminum as a reaction gas component, according to any one of (1) to (7) Method for manufacturing a surface-coated cutting tool. "
It has the characteristics.
The “inside crystal grain average orientation difference” means a GOS (Grain Orientation Spread) value described later.

In the surface-coated cutting tool which is an embodiment of the present invention (hereinafter referred to as “the surface-coated cutting tool of the present invention” or “the cutting tool of the present invention”), the surface-coated cutting provided with a hard coating layer on the surface of the tool base. In the tool, the hard coating layer includes at least a composite nitride or composite carbonitride layer of Cr and Al having an average layer thickness of 1 to 20 μm, and has a composition formula: (Cr _1-x Al _x ) (C _y N _1-y ) In particular, the average content ratio x _avg in the total amount of Cr and Al in Al and the average content ratio y _avg in the total amount of C and N in C (where x _avg and y _avg are both (Atomic ratio) satisfy 0.70 ≦ x _avg ≦ 0.95 and 0 ≦ y _avg ≦ 0.005, respectively, and the crystal grains constituting the composite nitride or composite carbonitride layer are NaCl-type faces. There are those having a centered cubic structure, and the crystal orientation of the crystal grains When analyzing from the longitudinal cross-section direction using a side-scattering diffractometer and determining the average orientation difference within each crystal grain, the crystal grains exhibiting an average orientation difference within the crystal grain of 2 degrees or more are complex nitride or composite The presence of 40% or more by area ratio with respect to the entire carbonitride layer causes distortion in the crystal grains having a cubic structure, thereby improving the hardness and toughness of the crystal grains. As a result, chipping resistance is improved. The effect of improving the wear resistance without damaging is exhibited, and the cutting performance superior to the conventional hard coating layer is exhibited over a long period of use, and the life of the coated tool is extended.
In the surface-coated cutting tool in which a hard coating layer is provided on the surface of the tool base, the hard coating layer includes at least a composite nitride or composite carbonitride layer of Ti, Al, and Me having an average layer thickness of 1 to 20 μm. In particular, when represented by the composition formula: (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ), in particular, the Ti of the composite nitride or the composite carbonitride layer is composed of Ti, Al, and Me. The average content ratio α _avg in the total amount and the average content ratio β _avg in the total amount of Ti, Al and Me in Me and the average content ratio γ _avg in the total amount of C and N in C (where α _avg , β _avg and γ _avg are atomic ratios) of 0.60 ≦ α _avg , 0.005 ≦ β _avg ≦ 0.10, 0 ≦ γ _avg ≦ 0.005, 0.605 ≦ α _avg + β _avg ≦, respectively. 0.95 is satisfied. The crystal grains constituting the composite carbonitride layer have a cubic structure, and the crystal orientation of the crystal grains is analyzed from the longitudinal cross-sectional direction using an electron beam backscattering diffractometer. When the average orientation difference within the crystal grains is determined, the crystal grains having an average orientation difference within the crystal grains of 2 degrees or more are present in an area ratio of 40% or more with respect to the entire composite nitride or composite carbonitride layer. Since distortion occurs in the crystal grains having a cubic crystal structure, the hardness and toughness of the crystal grains are improved. As a result, the effect of improving the chipping resistance without impairing the wear resistance is exhibited. Compared with the conventional hard coating layer, it exhibits excellent cutting performance over a long period of use, and the length of the coated tool is improved. Life expectancy is achieved.

The present invention coated tool has a Cr-Al composite nitride or composite carbonitride layer, or a Ti-Al and Me composite nitride or composite carbonitride layer of NaCl type face-centered cubic structure (cubic). The schematic explanatory drawing of the measuring method of the crystal grain average orientation difference of a crystal grain is shown. The cross section of the composite nitride or composite carbonitride of Cr and Al, or the composite nitride or composite carbonitride layer of Ti, Al, and Me which comprises the hard coating layer which the surface coating cutting tool of this invention has is typically FIG. In the cross section of the composite nitride layer or composite carbonitride layer of Cr and Al constituting the hard coating layer of the coated tool of the present invention, within the crystal grains of individual crystal grains having a NaCl-type face-centered cubic structure (cubic crystal) An example of the histogram which shows the area ratio of a mean orientation difference (GOS) is shown. The vertical dotted line in the histogram indicates a boundary line having an average misorientation within the grain of 2 °, and the bar on the right side of the vertical dotted line in the figure has an average misorientation within the grain of 2 ° or more. The thing is shown. The same applies to FIGS. 4 to 6 below. In the cross section of the composite nitride layer or composite carbonitride layer of Cr and Al constituting the hard coating layer of the comparative coated tool, within the crystal grains of individual crystal grains having a NaCl type face centered cubic structure (cubic crystal) An example of the histogram about the area ratio of a mean orientation difference (GOS) is shown. In the cross section of the composite nitride layer or composite carbonitride layer of Ti, Al, and Me constituting the hard coating layer of the coated tool of the present invention corresponding to an embodiment of the present invention, a NaCl type face-centered cubic structure (cubic crystal) ) Shows an example of a histogram showing the area ratio of the average orientation difference (GOS value) in crystal grains of individual crystal grains having. Each of the cross-sections of the composite nitride layer or composite carbonitride layer of Ti, Al and Me constituting the hard coating layer of the comparative coated tool which is a comparative coated tool has an NaCl type face-centered cubic structure (cubic crystal). 2 shows an example of a histogram of the area ratio of average orientation difference (GOS value) in crystal grains of the crystal grains.

The form for implementing this invention is demonstrated below.

Average layer thickness of the composite nitride or composite carbonitride layer constituting the hard coating layer:
The hard coating layer of the present invention comprises a chemical vapor deposited composition formula: (Cr _1-x Al _x ) (C _y N _1-y ) Cr and Al composite nitride or composite carbonitride layer, or At least one of a composite nitride or composite carbonitride layer of Ti, Al, and Me represented by the composition formula: (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) Including. This composite nitride or composite carbonitride layer has high temperature hardness and excellent wear resistance, but the effect is particularly remarkable when the average layer thickness is 1 to 20 μm. The reason is that if the average layer thickness is less than 1 μm, the layer thickness is so thin that sufficient wear resistance over a long period of time cannot be secured, while if the average layer thickness exceeds 20 μm, the composite The crystal grains of the nitride or composite carbonitride layer are easily coarsened, and chipping is likely to occur. Therefore, the average layer thickness is set to 1 to 20 μm.

Composition of composite nitride or composite carbonitride layer constituting hard coating layer:
(1) When the composite nitride or composite carbonitride layer of Cr and Al of the present invention is expressed by a composition formula: (Cr _1-x Al _x ) (C _y N _1-y ), the Cr and Al of Al The average content ratio x _avg in the total amount and the average content ratio y _avg in the total amount of C and N in C (where x _avg and y _avg are atomic ratios) are respectively 0.70 ≦ x _avg ≦ It is preferable to control to satisfy 0.95 and 0 ≦ y _avg ≦ 0.005.
The reason is that when the average content ratio x _avg of Al is less than 0.70, the high-temperature hardness of the composite nitride or composite carbonitride layer of Cr and Al is not sufficient, and the oxidation resistance is also inferior, When subjected to high-speed intermittent cutting of alloy steel or the like, the wear resistance is not sufficient. On the other hand, if the average content ratio x _{avg of} Al exceeds 0.95, the average content ratio of Cr relatively decreases, leading to embrittlement and chipping resistance. Therefore, the average Al content ratio x _avg was determined to be 0.70 ≦ x _avg ≦ 0.95.
Further, when the average content ratio (atomic ratio) y _avg of the C component contained in the composite nitride or composite carbonitride layer is a minute amount in the range of 0 ≦ y _avg ≦ 0.005, the composite nitride or composite carbon The adhesion between the nitride layer and the tool substrate or the lower layer is improved, and the impact during cutting is reduced by improving the lubricity. As a result, the fracture resistance of the composite nitride or the composite carbonitride layer and Chipping resistance is improved. On the other hand, if the average content ratio y of the component C deviates from the range of 0 ≦ y _avg ≦ 0.005, the toughness of the composite nitride or composite carbonitride layer is lowered, so that the chipping resistance and chipping resistance are reduced. Therefore, it is not preferable. Therefore, the average content ratio y _avg of the C component was set to 0 ≦ y _avg ≦ 0.005.
(2) When the composite nitride or composite carbonitride layer of Ti, Al, and Me of the present invention is represented by a composition formula: (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) ( However, Me is a kind of element selected from Si, Zr, B, V, and Cr), the average content ratio α _avg in the total amount of Ti, Al, and Me of Al, and of Ti, Al, and Me of Me The average content ratio β _avg in the total amount and the average content ratio γ _avg in the total amount of C and N in C ₍ where α _avg , β _avg , and γ _avg are atomic ratios) are 0.60 ≦ It is preferable to control so that α _avg , 0.005 ≦ β _avg ≦ 0.10, 0 ≦ γ _avg ≦ 0.005, 0.605 ≦ α _avg + β _avg ≦ 0.95.
The reason is that when the average Al content ratio α _avg is less than 0.60, the composite nitride or composite carbonitride layer of Ti and Al and Me is inferior in hardness, so it is suitable for high-speed intermittent cutting of alloy steel and the like. If provided, the wear resistance is not sufficient.
Further, when the average content ratio β _{avg of} Me is less than 0.005, the composite nitride of Ti and Al and Me or the composite carbonitride layer 2 is inferior in hardness, so that it can be used for high-speed intermittent cutting of alloy steel and the like. In such a case, the wear resistance is not sufficient. On the other hand, if it exceeds 0.10, the segregation of Me to the grain boundaries, etc., the toughness of the composite nitride or composite carbonitride layer of Ti, Al, and Me will decrease, and it will be subjected to high-speed intermittent cutting of alloy steel etc. The chipping resistance is not sufficient. Therefore, the average content ratio β _avg of Me was defined as 0.005 ≦ β _avg ≦ 0.10.
On the other hand, if the sum α _avg + β _avg of the average content ratio α _{avg of} Al and the average content ratio β _{avg of} Me is less than 0.605, the hardness of the composite nitride or composite carbonitride layer of Ti, Al, and Me Therefore, when it is subjected to high-speed intermittent cutting of alloy steel or the like, the wear resistance is not sufficient, and if it exceeds 0.95, the Ti content is relatively reduced, leading to embrittlement. , Chipping resistance is reduced. Therefore, the sum α _avg + β _avg of the average content ratio α _{avg of} Al and the average content ratio β _{avg of} Me was determined as 0.605 ≦ α _avg + β _avg ≦ 0.95.
Here, as a specific component of Me, a kind of element selected from Si, Zr, B, V, and Cr is used.
When the Si component or the B component is used so that β _avg is 0.005 or more as Me, the hardness of the composite nitride or composite carbonitride layer is improved, so that the wear resistance is improved. The Zr component has the effect of strengthening the grain boundaries, and the V component improves toughness, so that the chipping resistance is further improved, and the Cr component improves oxidation resistance. The tool life is expected to be even longer. However, in any component, when the average content ratio β _avg exceeds 0.10, the average content ratio of the Al component and the Ti component is relatively decreased, so that the wear resistance or chipping resistance tends to decrease. Therefore, it must be avoided that the average content ratio of β _avg exceeds 0.10.
Further, when the average content ratio (atomic ratio) γ _avg of C contained in the composite nitride or composite carbonitride layer is a small amount in the range of 0 ≦ γ _avg ≦ 0.005, the composite nitride or composite carbonitride The adhesion between the material layer and the tool base or the lower layer is improved and the lubricity is improved to reduce the impact during cutting. As a result, the fracture resistance and resistance of the composite nitride or composite carbonitride layer are reduced. Chipping property is improved. On the other hand, if the average content ratio γ _{avg of} C deviates from the range of 0 ≦ γ _avg ≦ 0.005, the toughness of the composite nitride or composite carbonitride layer decreases, so the chipping resistance and chipping resistance decrease on the contrary. Therefore, it is not preferable. Therefore, the average content ratio γ _avg of C was determined as 0 ≦ γ _avg ≦ 0.005.

Intra-grain average orientation difference (GOS value) of individual crystal grains having a NaCl-type face-centered cubic structure constituting the composite nitride or composite carbonitride layer:
In the present invention, an electron beam backscatter diffractometer is used to determine the average orientation difference in cubic Cr and Al composite nitride or composite carbonitride crystal grains, and cubic Ti, Al and Me. The average orientation difference within the crystal grains of the composite nitride or composite carbonitride crystal grains is determined.
Specifically, the surface polished surface was analyzed at intervals of 0.1 μm from the direction perpendicular to the surface of the composite nitride or composite carbonitride layer, and as shown in FIG. 1, adjacent measurement points P (hereinafter, “ If there is a misorientation of 5 degrees or more between them (also referred to as “pixel”), this is defined as a grain boundary B. A region surrounded by the grain boundary B is defined as one crystal grain. However, a single pixel P having an orientation difference of 5 degrees or more with all adjacent pixels P is not a crystal grain, and a case where two or more pixels are connected is handled as a crystal grain.
Then, the orientation difference between a certain pixel P in a crystal grain having a cubic crystal structure and all other pixels in the same crystal grain is calculated, and this is obtained as the orientation difference in the crystal grain, and is averaged. Things are defined as GOS (Grain Orientation Spread) values. A schematic diagram is shown in FIG. The GOS value is described in, for example, the document “The Journal of the Japan Society of Mechanical Engineers (A) 71: 712 (2005-12) Paper No. 05-0367 1722-1728”.
In the present invention, “in-grain average orientation difference” means the GOS value. When the GOS value is expressed by a mathematical expression, the number of pixels in the same crystal grain is n, the numbers assigned to different pixels P in the same crystal grain are i and j (where 1 ≦ i, j ≦ n), pixel When the crystal orientation difference obtained from the crystal orientation at i and the crystal orientation at pixel j is α _{ij (i ≠ j)} ,

Can be expressed as
The average orientation difference and GOS value within a crystal grain are numerical values obtained by calculating the orientation difference between a certain pixel P in the crystal grain and all other pixels in the same crystal grain and averaging the values. In other words, a large numerical value is obtained when there are many continuous orientation changes in the crystal grains.

In-grain average orientation difference (GOS value) is within a measurement range of 25 × 25 μm using an electron beam backscattering diffractometer on the surface polished surface from a direction perpendicular to the surface of the composite nitride or composite carbonitride layer. The number of pixels belonging to a crystal grain having a cubic structure constituting the composite nitride or composite carbonitride layer is determined at intervals of 0.1 μm / step, and the total number of pixels belonging to the crystal grain is determined. By dividing the average misorientation at 1 degree intervals, and summing up the pixel P of the crystal grains whose average misorientation within the grain is included in the range of the value and dividing by the total number of pixels, It can be obtained by creating a histogram showing the area ratio.
3 to 6 show examples of histograms created in this way.

(1) Regarding the Cr and Al Composite Nitride or Composite Carbonitride Layer of the Present Invention FIG. 3 shows the crystal grains having the cubic structure of the Cr and Al composite nitride or composite carbonitride layer of the present invention. FIG. 3 is an example of a histogram of the average misorientation within a crystal grain. As shown in FIG. 3, the crystal grain having an average misorientation (GOS) value of 2 degrees or more is mixed with Cr and Al. It can be seen that the area proportion of the total area of the product or composite carbonitride layer is 40% or more.
FIG. 4 is an example of a histogram of average orientation difference within a crystal grain obtained for a crystal grain having a cubic structure of a conventional Cr and Al composite nitride or composite carbonitride layer. In FIG. The area ratio of the crystal grains having a mean grain orientation difference (GOS) value of 2 degrees or more to the total area of the composite nitride or composite carbonitride layer of Cr and Al is less than 40%.
As described above, the crystal grains having a cubic structure constituting the composite nitride or composite carbonitride layer of Cr and Al of the present invention have a large variation in crystal orientation in the crystal grains as compared with the conventional one. Therefore, an increase in strain in the crystal grains contributes to improvement in hardness and toughness and improvement in wear resistance.
A coated tool in which a hard coating layer including at least a (Cr _1-x Al _x ) (C _y N _1-y ) layer having an in _- grain average orientation difference is formed on the surface of a tool base is accompanied by high heat generation. At the same time, it exhibits excellent chipping resistance and wear resistance by high-speed intermittent cutting of alloy steel or the like in which an impact load is applied to the cutting edge.
However, when the area ratio of the crystal grains showing the average orientation difference in the crystal grains of 2 degrees or more to the total area of the composite nitride or composite carbonitride layer of Cr and Al is less than 40%, Since the effect of improving the hardness and toughness due to the internal strain of the grains is not sufficient, the crystal grains having a cubic structure in which the average misorientation within the grains is 2 degrees or more are composed of a composite nitride or composite carbonitride layer of Cr and Al The area ratio of the total area is 40% or more.
The area ratio of crystal grains having an average orientation difference within the crystal grains of 2 degrees or more with respect to the area of the preferred composite nitride or composite carbonitride layer is 45 to 70%. The area ratio of the crystal grains having an average orientation difference within the crystal grains of 2 degrees or more with respect to the area of the more preferable composite nitride or composite carbonitride layer is 50 to 65%.

(2) About Ti, Al and Me Composite Nitride or Composite Carbonitride Layer of the Present Invention FIG. 5 has a cubic structure of the Ti, Al and Me composite nitride or composite carbonitride layer of the present invention. FIG. 5 is an example of a histogram of the average orientation difference within a crystal grain obtained for a crystal grain. As shown in FIG. 5, a crystal grain having an average orientation difference within a crystal grain (GOS) value of 2 degrees or more is Ti. It can be seen that the area ratio in the total area of the composite nitride or composite carbonitride layer of Al and Me is 40% or more.
FIG. 6 is an example of a histogram of average orientation difference in crystal grains obtained for crystal grains having a cubic structure of a composite nitride or composite carbonitride layer of Ti, Al, and Me of the comparative tool. , The area ratio of the crystal grains having a mean grain orientation difference (GOS) value of 2 degrees or more to the total area of the composite nitride or composite carbonitride layer of Ti, Al, and Me is less than 40%. is there.
Thus, the crystal grains having a cubic structure constituting the composite nitride or composite carbonitride layer of Ti, Al, and Me of the present invention have a variation in crystal orientation within the crystal grains as compared with the conventional one. Therefore, an increase in strain within the crystal grains contributes to improvement in hardness and toughness.
A coated tool in which a hard coating layer including at least a (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) layer having an average orientation difference in crystal grains is coated on a tool base surface, It exhibits excellent chipping resistance and wear resistance in high-speed intermittent cutting of alloy steel and the like that cause high heat generation and an impact load on the cutting edge.
However, when the area ratio of the crystal grains having an average orientation difference within the crystal grains of 2 degrees or more to the total area of the composite nitride or composite carbonitride layer of Ti, Al, and Me is less than 40% Since the effect of improving the hardness and toughness due to the internal strain of the crystal grains is not sufficient, the crystal grains having a cubic structure in which the average orientation difference in the grains is 2 degrees or more are Ti, Al and Me composite nitride or composite The area ratio in the total area of the carbonitride layer is 40% or more.
Thus, the crystal grains constituting the composite nitride or composite carbonitride layer of Al, Ti and Me of the surface-coated cutting tool of the present invention are compared with the crystal grains constituting the conventional TiAlN layer, Since the crystal orientation varies greatly within the crystal grains, that is, there is distortion, this contributes to the improvement of hardness and toughness.
The area ratio of crystal grains having an average orientation difference within the crystal grains of 2 degrees or more with respect to the area of the preferred composite nitride or composite carbonitride layer is 45 to 70%. The area ratio of the crystal grains having an average orientation difference within the crystal grains of 2 degrees or more with respect to the area of the more preferable composite nitride or composite carbonitride layer is 50 to 65%.

Crystal structure of hard coating layer:
(1) Cr and Al composite nitride or composite carbonitride layer of the present invention Cr and Al composite nitride or composite carbonitride layer is a composite nitride of Cr and Al having a NaCl-type face-centered cubic structure. In the case of a single phase of a product or a composite carbonitride, particularly excellent chipping resistance and wear resistance are exhibited.
In addition, even when the composite nitride or composite carbonitride layer of Cr and Al is not a NaCl type face-centered cubic structure single phase, the electron beam is used for the composite nitride or composite carbonitride layer of Cr and Al. Using a backscatter diffractometer, analysis is performed at intervals of 0.1 μm from the longitudinal cross-sectional direction, the width is 10 μm, the vertical measurement is performed from the vertical cross-sectional direction within the measurement range of the film thickness, and the composite nitride or The total number of pixels belonging to the crystal grains having a cubic structure constituting the composite carbonitride layer is obtained, and the composite nitride or composite is determined according to the ratio to the total number of measured pixels in the measurement with respect to the hard coating layer in the five fields of view. When the area ratio of the NaCl type face centered cubic crystal grains constituting the carbonitride layer was determined, and the area ratio of the NaCl type face centered cubic crystal grains was less than 70% by area, wear resistance was obtained. There is a tendency to decline When this area ratio is 70% by area or more, excellent chipping resistance and wear resistance are exhibited. Therefore, a Cr-Al composite nitride or composite carbonitride having an NaCl type face-centered cubic structure. The proportion of the physical phase is desirably 70 area% or more.
(2) Ti, Al, and Me composite nitride or composite carbonitride layer of the present invention When the hard coating layer has a cubic structure single phase, particularly excellent wear resistance is exhibited.
Further, even when the hard coating layer is not a cubic structure single phase, the hard coating layer is analyzed at an interval of 0.1 μm from the longitudinal cross-sectional direction using an electron beam backscattering diffractometer, and the width is 10 μm. The measurement from the longitudinal cross-sectional direction within the measurement range of the film thickness is carried out in five fields of view, and the total number of pixels belonging to the crystal grains having a cubic structure constituting the composite nitride or composite carbonitride layer is obtained, When the area ratio of the crystal grains having the cubic structure constituting the composite nitride or composite carbonitride layer was determined by the ratio to the total number of pixels measured in the hard coating layer in five fields of view, the cubic crystal When the area ratio of the crystal grains having a structure is less than 70%, a tendency to decrease the wear resistance is observed. On the other hand, when the area ratio is 70% or more, excellent chipping resistance and wear resistance are observed. From the fact that The phase of Ti, Al and Me composite nitride or composite carbonitride having a tetragonal structure is desirably 70 area% or more.

Lower layer and upper layer:
The composite nitride or composite carbonitride layer of Cr and Al of the present invention and the composite nitride or composite carbonitride layer of Ti, Al, and Me of the present invention alone have a sufficient effect. A lower part having a total average layer thickness of 0.1 to 20 μm, comprising one or more Ti compound layers of a carbide layer, a nitride layer, a carbonitride layer, a carbonate layer, and a carbonitride layer. When the layers are provided and / or when the upper layer including at least the aluminum oxide layer is provided with a total average layer thickness of 1 to 25 μm, combined with the effects of these layers, the characteristics are further improved. Can be created. When providing a lower layer made of one or two or more Ti compound layers of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride oxide layer, the total average layer of the lower layer If the thickness is less than 0.1 μm, the effect of the lower layer is not sufficiently achieved. On the other hand, if it exceeds 20 μm, the crystal grains are likely to be coarsened and chipping is likely to occur. Moreover, if the total average layer thickness of the upper layer including the aluminum oxide layer is less than 1 μm, the effect of the upper layer is not sufficiently achieved. .

A cross section of a composite nitride or composite carbonitride layer of Cr and Al or a composite nitride or composite carbonitride layer of Ti, Al, and Me constituting the hard coating layer of the surface-coated cutting tool of the present invention A diagrammatic representation is shown in FIG.

Next, the coated tool of the present invention will be specifically described with reference to examples.
As an example, a coated tool using a WC-based cemented carbide or TiCN-based cermet as a tool base will be described, but the same applies when a cubic boron nitride-based ultra-high pressure sintered body is used as the tool base.

As raw material powders, WC powder, TiC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder and Co powder all having an average particle diameter of 1 to 3 μm are prepared, and these raw material powders are blended as shown in Table 1. Blended into the composition, added with wax, mixed in a ball mill in acetone for 24 hours, dried under reduced pressure, pressed into a compact of a predetermined shape at a pressure of 98 MPa, and the compact was 1370 in a vacuum of 5 Pa. Vacuum sintered under the condition of holding for 1 hour at a predetermined temperature in the range of ~ 1470 ° C, and after sintering, manufacture tool bodies A to C made of WC-base cemented carbide with ISO standard SEEN1203AFSN insert shape, respectively. did.

In addition, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, WC powder, Co powder, all having an average particle diameter of 0.5 to 2 μm. And Ni powder are prepared, these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and then pressed into a compact at a pressure of 98 MPa. The body was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, a tool base D made of TiCN-based cermet having an ISO standard SEEN1203AFSN insert shape was produced.

Next, a chemical vapor deposition apparatus is used on the surfaces of these tool bases A to D,
Formation conditions A to J shown in Tables 4 and 5, that is, a gas group A composed of NH ₃ and H ₂ , a gas group B composed of CrCl ₃ , AlCl ₃ , N ₂ , and H ₂ , and supply of each gas As a method, the reaction gas composition (capacity% with respect to the total of the gas group A and the gas group B) is set as NH ₃ : 2.0 to 3.0%, H ₂ : 65 to 75% as the gas group A, and the gas group. As B, AlCl ₃ : 0.6 to 0.9%, CrCl ₃ : 0.2 to 0.3%, Al (CH ₃ ) ₃ : 0 to 0.5%, N ₂ : 12.5 to 15.0 %, H ₂ : remaining, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 700 to 900 ° C., supply cycle 3 to 4 seconds, gas supply time per cycle 0.15 to 0.25 seconds The phase difference between the supply of the gas group A and the gas group B is 0.10 to 0.20 seconds, A CVD method is performed, and crystal grains having a cubic structure in which the average orientation difference in crystal grains shown in Table 7 is 2 degrees or more are present in the area ratio shown in Table 7, and have the target layer thickness shown in Table 7 The coated tools 1 to 15 of the present invention were manufactured by forming a hard coating layer including a (Cr _1-x Al _x ) (C _y N _1-y ) layer.
For the coated tools 6 to 13 of the present invention, the lower layer shown in Table 6 and / or the upper layer shown in Table 7 were formed under the formation conditions shown in Table 3.

For comparison purposes, at least the surfaces of the tool bases A to D were subjected to the conditions shown in Tables 4 and 5 and the target layer thickness (μm) shown in Table 8, at least as in the present coated tools 1 to 15. A hard coating layer including a composite nitride or composite carbonitride layer of Cr and Al was deposited. At this time, a comparison is made by forming a hard coating layer so that the reaction gas composition on the surface of the tool base does not change with time during the film formation process of the (Cr _1-x Al _x ) (C _y N _1-y ) layer. Coated tools 1-13 were produced.
Similar to the coated tools 6 to 13 of the present invention, the comparative coated tools 6 to 13 are formed with the lower layer shown in Table 6 and / or the upper layer shown in Table 8 under the forming conditions shown in Table 3. did.

For reference, the (Cr _1-x Al _x ) (C _y N _1-y ) layer of the reference example is formed on the surfaces of the tool base B and the tool base C by arc ion plating using a conventional physical vapor deposition apparatus. The reference coated tools 14 and 15 shown in Table 8 were produced by vapor-depositing with a target layer thickness.
The arc ion plating conditions used for the vapor deposition in the reference example are as follows.
(A) The tool bases B and C are ultrasonically washed in acetone and dried, and the outer periphery is positioned at a predetermined distance in the radial direction from the central axis on the rotary table in the arc ion plating apparatus. In addition, an Al—Cr alloy having a predetermined composition is arranged as a cathode electrode (evaporation source),
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 10 ⁻² Pa or less, the inside of the apparatus is heated to 500 ° C. with a heater, and then the tool base that rotates while rotating on the rotary table is set to −1000 V. A DC bias voltage is applied and a current of 200 A is passed between a cathode electrode and an anode electrode made of an Al—Cr alloy to generate an arc discharge, thereby generating Al and Cr ions in the apparatus, thereby providing a tool base. Clean the surface with bombard,
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 4 Pa, a DC bias voltage of −50 V is applied to the tool base that rotates while rotating on the rotary table, and A current of 120 A is passed between the cathode electrode (evaporation source) made of the Al—Cr alloy and the anode electrode to generate an arc discharge, and the target composition and target layer shown in Table 8 are formed on the surface of the tool base. A thick (Cr _1-x Al _x ) (C _y N _1-y ) layer was formed by vapor deposition to produce reference coated tools 14 and 15.

In addition, the cross sections in the direction perpendicular to the tool base of the constituent layers of the coated tools 1 to 15 of the present invention, the comparative coated tools 1 to 13 and the reference coated tools 14 and 15 are measured using a scanning electron microscope (5000 magnifications). When the average layer thickness was obtained by measuring and averaging the five layer thicknesses in the observation field, all showed the same average layer thickness as the target layer thicknesses shown in Tables 6 to 8. .

For the average Al content ratio x _avg of the composite nitride or composite carbonitride layer, an electron beam sample is used in a sample whose surface is polished using an electron-beam-microanalyzer (EPMA). Irradiation was performed from the surface side, and an average Al content ratio x _avg of Al was determined from an average of 10 points of the analysis results of the obtained characteristic X-rays. The average C content ratio y was determined by secondary ion mass spectrometry (Secondary-Ion-Mass- Spectroscopy: SIMS). The ion beam was irradiated in the range of 70 μm × 70 μm from the sample surface side, and the concentration in the depth direction was measured for the components emitted by the sputtering action. The average C content ratio y _avg indicates an average value in the depth direction of the composite nitride or composite carbonitride layer of Cr and Al. However, the content ratio of C excludes the inevitable content ratio of C that is included without intentionally using a gas containing C as a gas raw material. Specifically, the content ratio (atomic ratio) of the C component contained in the composite nitride or composite carbonitride layer when the supply amount of Al (CH ₃ ) ₃ is 0 is determined as the inevitable C content ratio. , The inevitable C content is subtracted from the C component content (atomic ratio) contained in the composite nitride or composite carbonitride layer obtained when Al (CH ₃ ) ₃ is intentionally supplied. The value was determined as _yavg .

In addition, the crystal orientation of each crystal grain having a cubic structure constituting the composite nitride or composite carbonitride layer of Cr and Al is analyzed from the longitudinal cross-sectional direction using an electron beam backscatter diffractometer, and adjacent pixels are analyzed. If there is a misorientation of 5 degrees or more between them, this is the grain boundary, and the region surrounded by the grain boundary is one crystal grain. One pixel in the crystal grain and all other pixels in the same crystal grain The difference in orientation within the grain is calculated between 0 degree and less than 1 degree, 1 degree and less than 2 degree, 2 degree and less than 3 degree, 3 degree and less than 4 degree, and so on. The range of 10 degrees was divided and mapped every 1 degree. From the mapping diagram, the area ratio of the crystal grains having an average orientation difference in the crystal grains of 2 degrees or more to the entire composite nitride or composite carbonitride layer of Cr and Al was obtained.
FIG. 3 shows an example of a histogram of the average orientation difference in crystal grains measured for the coated tool 2 of the present invention, and FIG. 4 shows an example of a histogram of the average orientation difference in crystal grains measured for the comparative coating tool 12. Show.
Furthermore, the composite nitride or composite carbonitride layer of Cr and Al was analyzed at intervals of 0.1 μm from the longitudinal cross-section direction using an electron beam backscattering diffractometer, the width was 10 μm, and the length was within the measurement range of the film thickness. The measurement from the longitudinal cross-sectional direction is performed in five fields of view, and the total number of pixels belonging to the crystal grains having the cubic structure constituting the composite nitride or composite carbonitride layer is obtained. Depending on the ratio to the number of measurement pixels, the crystal grains of the NaCl type face-centered cubic structure constituting the composite nitride or composite carbonitride layer are formed in the longitudinal section of the composite nitride or composite carbonitride layer of Cr and Al. The area ratio (area%) was calculated.
Tables 7 and 8 show these results.

Next, the coated tools 1 to 15 according to the present invention, the comparative coated tools 1 to 13 and the reference coated tool are used in the state where each of the various coated tools is clamped to the tool steel cutter tip portion having a cutter diameter of 125 mm by a fixing jig. For 14 and 15, the following dry dry high-speed face milling, which is a kind of high-speed intermittent cutting of carbon steel, and a center-cut cutting test were performed, and the flank wear width of the cutting edge was measured.
Tool substrate: Tungsten carbide-based cemented carbide, titanium carbonitride-based cermet,
Cutting test: dry high-speed face milling, center cutting,
Work material: Block material of JIS / S55C width 100mm, length 400mm,
Rotational speed: 815 min ⁻¹
Cutting speed: 320 m / min,
Cutting depth: 1.0 mm,
Single blade feed: 0.1 mm / tooth,
Cutting time: 8 minutes
The results are shown in Table 9.

As raw material powders, WC powder, TiC powder, ZrC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder and Co powder each having an average particle diameter of 1 to 3 μm are prepared. Compounded in the formulation shown in Table 10, added with wax, ball mill mixed in acetone for 24 hours, dried under reduced pressure, press-molded into a green compact of a predetermined shape at a pressure of 98 MPa. In a 5 Pa vacuum, vacuum sintering is performed at a predetermined temperature within a range of 1370 to 1470 ° C. for 1 hour, and after sintering, the cutting edge is subjected to a honing process of R: 0.07 mm. Tool bases α to γ made of WC-base cemented carbide having the insert shape of CNMG120212 were manufactured.

In addition, as raw material powders, TiCN (TiC / TiN = 50/50 by mass ratio) powder, NbC powder, WC powder, Co powder, and Ni powder each having an average particle diameter of 0.5 to 2 μm are prepared, These raw material powders were blended into the composition shown in Table 11, wet mixed with a ball mill for 24 hours, dried, and then pressed into a green compact at a pressure of 98 MPa. Sintered in an atmosphere at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge part is subjected to a honing process of R: 0.09 mm so that the TiCN base has an insert shape of ISO standard / CNMG120212 A cermet tool substrate δ was formed.

Next, a chemical vapor deposition apparatus is used on the surfaces of these tool bases α to γ and tool base δ, and at least (Cr _1-x Al) under the conditions shown in Tables 4 and 5 by the same method as in Example 1. _The coated tools 16 to 30 according to the present invention shown in Table 12 were manufactured by vapor-depositing a hard coating layer containing _x ) (C _y N _1-y ) layer at a target layer thickness.
For the coated tools 19 to 28 of the present invention, the lower layer shown in Table 12 and / or the upper layer shown in Table 13 were formed under the formation conditions shown in Table 3.

Also, for comparison purposes, the coated tool of the present invention was similarly used on the surfaces of the tool bases α to γ and the tool base δ, using chemical vapor deposition equipment, with the conditions shown in Tables 4 and 5 and the target layer thicknesses shown in Table 14. Comparative coating tools 16 to 28 shown in Table 14 were produced by vapor-depositing a hard coating layer in the same manner as described above.
As with the coated tools 19 to 28 of the present invention, the comparative coated tools 19 to 28 are formed with the lower layer shown in Table 12 and / or the upper layer shown in Table 14 under the forming conditions shown in Table 3. did.

For reference, the (Cr _1-x Al _x ) (C _y N _1-y ) layer of the reference example is formed on the surfaces of the tool base β and the tool base γ by arc ion plating using a conventional physical vapor deposition apparatus. The reference coating tools 29 and 30 shown in Table 14 were manufactured by vapor-depositing with a target layer thickness.
In addition, the conditions similar to the conditions shown in Example 1 were used for the conditions of arc ion plating.

Further, the cross-sections of the constituent layers of the inventive coated tools 16 to 30, the comparative coated tools 16 to 28 and the reference coated tools 29 and 30 were measured using a scanning electron microscope (magnification 5000 times), and 5 in the observation field of view. When the average layer thickness was obtained by measuring the layer thickness at the points, the average layer thickness was substantially the same as the target layer thickness shown in Tables 12 to 14.

In addition, the crystal orientation of each crystal grain having a cubic structure constituting the composite nitride or composite carbonitride layer of Cr and Al is analyzed from the longitudinal cross-sectional direction using an electron beam backscatter diffractometer. The difference in direction is 0 degree or more, less than 1 degree, 1 degree or more, less than 2 degree, 2 degree or more, less than 3 degree, 3 degree or more, less than 4 degree, and so on. did. From the mapping diagram, the area ratio of the crystal grains having the average orientation difference in crystal grains and the orientation difference in crystal grains of 2 degrees or more to the entire composite nitride or composite carbonitride layer of Cr and Al was obtained.
Further, the ratio of the area of the crystal grains of the NaCl-type face-centered cubic structure constituting the composite nitride or composite carbonitride layer of Cr and Al to the longitudinal section of the composite nitride or composite carbonitride layer of Cr and Al The results of obtaining (area%) are shown in Table 13 and Table 14.

Next, in the state where all the various coated tools are screwed to the tip of the tool steel tool with a fixing jig, the coated tools 16 to 30 of the present invention, the comparative coated tools 16 to 28, the reference coated tool 29, For 30, a dry high-speed intermittent cutting test of carbon steel and a wet high-speed intermittent cutting test of ductile cast iron shown below were carried out, and the flank wear width of the cutting edge was measured.
Cutting condition 1:
Work material: JIS / S55C lengthwise equidistant round bars with 4 vertical grooves,
Cutting speed: 345 m / min,
Cutting depth: 2.0 mm
Feed: 0.1 mm / rev,
Cutting time: 5 minutes
(Normal cutting speed is 220 m / min),
Cutting condition 2:
Work material: JIS / FCD700 lengthwise equal length 4 round bar with round groove,
Cutting speed: 325 m / min,
Incision: 1.5mm,
Feed: 0.1 mm / rev,
Cutting time: 5 minutes
(Normal cutting speed is 180 m / min),
Table 15 shows the results of the cutting test.

From the results shown in Tables 9 and 15, the coated tool according to the present invention has a predetermined intragranular average within the crystal grains having a cubic structure constituting the composite nitride or composite carbonitride layer of Cr and Al. The presence of misorientation improves hardness due to crystal grain distortion and improves toughness while maintaining high wear resistance. Moreover, even when used for high-speed intermittent cutting where intermittent and impactful high loads act on the cutting edge, it has excellent chipping resistance and chipping resistance, resulting in excellent wear resistance over a long period of use. It is clear that it will work.

On the other hand, in the crystal grains having a cubic structure constituting the composite nitride of Cr and Al or the composite carbonitride layer constituting the hard coating layer, there is no predetermined intra-grain average orientation difference. The comparative coated tools 1 to 13, 16 to 28 and the reference coated tools 14, 15, 29 and 30 are used for high-speed intermittent cutting with high heat generation and intermittent / impact high loads acting on the cutting edge. It is clear that the life is shortened in a short time due to occurrence of chipping, chipping or the like.

As raw material powders, WC powder, TiC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder and Co powder all having an average particle diameter of 1 to 3 μm are prepared, and these raw material powders are blended as shown in Table 16. Blended into the composition, added with wax, mixed in a ball mill in acetone for 24 hours, dried under reduced pressure, pressed into a compact of a predetermined shape at a pressure of 98 MPa, and the compact was 1370 in a vacuum of 5 Pa. WC-based cemented carbide tool bases E to G with ISO standard SEEN1203AFSN insert shape after vacuum sintering under the condition of holding for 1 hour at a predetermined temperature within the range of ~ 1470 ° C. did.

In addition, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, WC powder, Co powder all having an average particle diameter of 0.5 to 2 μm. And Ni powder are prepared, these raw material powders are blended in the blending composition shown in Table 17, wet mixed by a ball mill for 24 hours, dried, and then pressed into a compact at a pressure of 98 MPa. The body was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, a tool base H made of TiCN-based cermet having an ISO standard SEEN1203AFSN insert shape was produced.

Next, a chemical vapor deposition apparatus is used on the surfaces of these tool bases E to H, and the formation conditions shown in Tables 19 and 20, that is, a gas group A composed of NH ₃ and H ₂ , TiCl ₄ , Al (CH ₃ ) ₃ , AlCl ₃ , MeCl _n (however, any one of SiCl ₄ , ZrCl ₄ , BCl ₃ , VCl ₄ , CrCl ₂ ), a gas group B consisting of N ₂ , H ₂ , and a method for supplying each gas As the gas group A, the reaction gas composition (capacity% with respect to the total of the gas group A and the gas group B) is NH ₃ : 2.0 to 3.0%, H ₂ : 65 to 75%, the gas group B AlCl ₃ : 0.6 to 0.9%, TiCl ₄ : 0.2 to 0.3%, Al (CH ₃ ) ₃ : 0 to 0.5%, MeCl _n (however, SiCl ₄ , ZrCl ₄ , BCl ₃ , VCl ₄ , CrC l ₂ ): 0.1 to 0.2%, N ₂ : 12.5 to 15.0%, H ₂ : remaining, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature : 700 to 900 ° C., supply cycle 1 to 5 seconds, gas supply time per cycle 0.15 to 0.25 seconds, phase difference between gas group A and gas group B supply 0.10 to 0.20 seconds Then, the thermal CVD method is performed for a predetermined time, and the crystal grains having a cubic structure in which the average misorientation within the crystal grains shown in Table 22 is 2 degrees or more are present in the area ratio shown in Table 22 and shown in Table 22 The coated tools 31 to 45 of the present invention were manufactured by forming a hard coating layer composed of a (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) layer having a target layer thickness.
For the inventive coated tools 36 to 43, the lower layer shown in Table 21 and / or the upper layer shown in Table 22 were formed under the formation conditions shown in Table 18.

For comparison purposes, at least on the surfaces of the tool bases E to H, at the conditions shown in Tables 19 and 20 and the target layer thickness (μm) shown in Table 23, at least as in the coated tools 31 to 45 of the present invention. A hard coating layer including a composite nitride or composite carbonitride layer of Ti and Al was deposited. At this time, the hard coating layer is formed so that the reaction gas composition on the surface of the tool base does not change with time during the film formation process of the (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ ) layer. Thus, comparative coated tools 31 to 45 were produced.
Similar to the coated tools 36 to 43 of the present invention, the comparative coated tools 36 to 43 are formed with the lower layer shown in Table 21 and / or the upper layer shown in Table 23 under the forming conditions shown in Table 18. did.

Further, the cross-sections of the constituent layers of the inventive coated tools 31 to 45 and comparative coated tools 31 to 45 in the direction perpendicular to the tool substrate were measured using a scanning electron microscope (with a magnification of 5000 times), and within the observation field of view. When the average layer thickness was obtained by measuring and averaging the five layer thicknesses, all showed an average layer thickness substantially the same as the target layer thickness shown in Table 21 to Table 23.

The average Al content ratio and the average Me content ratio of the composite nitride or composite carbonitride layer were determined using an electron beam microanalyzer (Electron-Probe-Micro-Analyzer: EPMA) in a sample whose surface was polished. A line was irradiated from the sample surface side, and an average Al content ratio α _{avg of} Al and an average content ratio β _avg of Me were obtained from an average of 10 points of the analysis result of the obtained characteristic X-ray. The average C content γ _avg was determined by secondary ion mass spectrometry (Secondary-Ion-Mass-Spectroscopy: SIMS). The ion beam was irradiated in the range of 70 μm × 70 μm from the sample surface side, and the concentration in the depth direction was measured for the components emitted by the sputtering action. The average C content ratio γ _avg represents an average value in the depth direction of the composite nitride or composite carbonitride layer of Ti, Al, and Me. However, the content ratio of C excludes the inevitable content ratio of C that is included without intentionally using a gas containing C as a gas raw material. Specifically, the content ratio (atomic ratio) of the C component contained in the composite nitride or composite carbonitride layer when the supply amount of Al (CH ₃ ) ₃ is 0 is determined as the inevitable C content ratio. , The inevitable C content is subtracted from the C component content (atomic ratio) contained in the composite nitride or composite carbonitride layer obtained when Al (CH ₃ ) ₃ is intentionally supplied. The value was determined as γ _avg .

Furthermore, the crystal orientation of each crystal grain having a cubic structure constituting the composite nitride or composite carbonitride layer of Ti, Al, and Me is analyzed from the longitudinal cross-section direction using an electron beam backscatter diffraction apparatus, If there is an orientation difference of 5 degrees or more between the pixels to be used as a grain boundary, and the region surrounded by the grain boundary is a single crystal grain, one pixel in the crystal grain and all the other in the same crystal grain The crystal grain orientation difference is calculated between the pixels, and the crystal grain orientation difference is 0 degree or more and less than 1 degree, 1 degree or more and less than 2 degree, 2 degree or more and less than 3 degree, 3 degree or more and less than 4 degree, and so on. The range of 0 to 10 degrees was divided and mapped every 1 degree. From the mapping diagram, the area ratio of the crystal grains having an average orientation difference within the crystal grains of 2 degrees or more to the entire composite nitride or composite carbonitride layer of Ti, Al, and Me was obtained. The results are shown in Table 22 and Table 23.
FIG. 5 shows an example of a histogram of the average orientation difference in crystal grains measured for the coated tool of the present invention, and FIG. 6 shows an example of a histogram of the average orientation difference in crystal grains measured for the comparative coated tool.

Next, the coated tools 31 to 45 of the present invention and the comparative coated tools 31 to 45 in the state where each of the various coated tools is clamped to the tip of a cutter made of tool steel having a cutter diameter of 125 mm by a fixing jig will be described below. The dry high-speed face milling, which is a kind of high-speed intermittent cutting of carbon steel, and a center-cut cutting test were performed, and the flank wear width of the cutting edge was measured. The results are shown in Table 24.

Tool substrate: Tungsten carbide-based cemented carbide, titanium carbonitride-based cermet,
Cutting test: dry high-speed face milling, center cutting,
Work material: Block material of JIS / S55C width 100mm, length 400mm,
Rotational speed: 815 min ⁻¹
Cutting speed: 320 m / min,
Cutting depth: 1.5 mm,
Single blade feed: 0.1 mm / tooth,
Cutting time: 8 minutes

Using the same raw material powder as in Example 2, mixing with the same composition (see Table 10 and Table 11), and using the same manufacturing method (see paragraphs 0052 and 0053), an ISO standard CNMG120212 insert shape was formed. Tool bases α to γ made of WC base cemented carbide and tool base δ made of TiCN base cermet were produced, respectively.

Next, on the surfaces of these tool bases α to γ and tool base δ, at least (Ti _1-α−) is obtained under the conditions shown in Tables 19 and 20 by the same method as in Example 3 using a chemical vapor deposition apparatus. _The coated tools 46 to 60 of the present invention shown in Table 26 were manufactured by vapor-depositing a hard coating layer including a _β Al _α Me _β ) (C _γ N _1-γ ) layer with a target layer thickness.
For the inventive coated tools 49 to 58, the lower layer shown in Table 25 and / or the upper layer shown in Table 26 were formed under the formation conditions shown in Table 18.

Also, for comparison purposes, the coated tool of the present invention was used under the conditions shown in Tables 19 and 20 and the target layer thicknesses shown in Table 27 using chemical vapor deposition devices on the surfaces of the tool bases α to γ and the tool base δ. Comparative coating tools 46 to 60 shown in Table 27 were manufactured by vapor-depositing a hard coating layer in the same manner as described above.
Similar to the coated tools 49 to 58 of the present invention, the comparative coated tools 49 to 58 are formed with the lower layer shown in Table 25 and / or the upper layer shown in Table 27 under the forming conditions shown in Table 18. did.

Further, the cross-section of each constituent layer of the coated tool 46 to 60 of the present invention and the comparative coated tool 46 to 60 is measured using a scanning electron microscope (magnification 5000 times), and the layer thickness at five points in the observation field is measured. When the average layer thickness was obtained on average, all showed the average layer thickness substantially the same as the target layer thickness shown in Tables 25 to 27.
For the hard coating layers of the inventive coated tools 46 to 60 and comparative coated tools 46 to 60, the average Al content ratio α _avg , the average Me content ratio β _{The avg} , the average C content ratio γ _avg , and the area ratio of the cubic crystal phase in the crystal grains were determined.

Furthermore, the crystal orientation of each crystal grain having a cubic structure constituting a composite nitride or composite carbonitride layer of Ti and Al is analyzed from the longitudinal cross-sectional direction using an electron beam backscatter diffraction apparatus, The difference in direction is 0 degree or more, less than 1 degree, 1 degree or more, less than 2 degree, 2 degree or more, less than 3 degree, 3 degree or more, less than 4 degree, and so on. did. From the mapping diagram, the area ratio of the crystal grains having the average orientation difference in the crystal grains and the orientation difference in the crystal grains of 2 degrees or more to the entire composite nitride or composite carbonitride layer of Ti, Al, and Me was obtained. The results are shown in Table 26 and Table 27.

Next, the coated tools 46 to 60 of the present invention and the comparative coated tools 46 to 60 are shown below in a state where all the various coated tools are screwed to the tip of the tool steel tool with a fixing jig. A dry high-speed intermittent cutting test for carbon steel and a wet high-speed intermittent cutting test for cast iron were performed, and the flank wear width of the cutting edge was measured for both.
Cutting condition 1:
Work material: JIS / S55C lengthwise equidistant round bars with 4 vertical grooves,
Cutting speed: 355 m / min,
Cutting depth: 2.0 mm
Feed: 0.12 mm / rev,
Cutting time: 5 minutes
(Normal cutting speed is 220 m / min),
Cutting condition 2:
Work material: JIS / FCD700 lengthwise equal length 4 round bar with round groove,
Cutting speed: 335 m / min,
Incision: 1.5mm,
Feed: 0.12 mm / rev,
Cutting time: 5 minutes
(Normal cutting speed is 180 m / min),
Table 28 shows the results of the cutting test.

From the results shown in Tables 24 and 28, the coated tool of the present invention has a crystal structure having a cubic structure constituting a composite nitride or composite carbonitride layer of Al, Ti and Me constituting the hard coating layer. In this case, the presence of a predetermined difference in the average orientation within the crystal grains improves the toughness while maintaining high wear resistance due to the distortion of the crystal grains. Moreover, even when used for high-speed intermittent cutting where intermittent and impactful high loads act on the cutting edge, it has excellent chipping resistance and chipping resistance, resulting in excellent wear resistance over a long period of use. It is clear that it will work.

On the other hand, there is a predetermined intra-grain average orientation difference in the crystal grains having a cubic structure constituting the composite nitride of Al, Ti, and Me or the composite carbonitride layer constituting the hard coating layer. The comparative coated tools 31 to 45 and 46 to 60 which are not used are accompanied by high heat generation, and when used for high-speed intermittent cutting in which intermittent and impact high loads act on the cutting edge, chipping, chipping, etc. occur. It is clear that the lifetime is reached in a short time.

As described above, the coated tool of the present invention can be used not only for high-speed intermittent cutting of carbon steel, alloy steel, cast iron, etc., but also as a coated tool for various work materials, and for long-term use. Since it exhibits excellent chipping resistance and wear resistance, it can satisfactorily respond to higher performance of cutting equipment, labor saving and energy saving of cutting, and cost reduction.

DESCRIPTION OF SYMBOLS 1 Tool base | substrate 2 Hard coating layer 3 Composite nitride or composite carbonitride layer B Grain boundary P Measuring point (pixel)

Claims (8)

1. In a surface-coated cutting tool in which a hard coating layer is formed on the surface of a tool base composed of any of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, and cubic boron nitride-based ultrahigh pressure sintered body,
   (A) The hard coating layer is a composite nitride or composite carbonitride layer of Cr and Al having an average layer thickness of 1 to 20 μm, or Ti, Al and Me (where Me is Si, Zr, B, V , A compound nitride of at least one element selected from Cr) or a composite carbonitride layer,
   (B) The composite nitride or composite carbonitride layer includes at least a composite nitride or composite carbonitride phase having a NaCl-type face-centered cubic structure,
   (C) The crystal orientation of the crystal grains of the composite nitride or the composite carbonitride having a NaCl-type face-centered cubic structure among the crystal grains constituting the composite nitride or the composite carbonitride layer is determined by electron beam backscattering. When analyzing from the longitudinal section direction using a diffractometer and obtaining the average orientation difference within each crystal grain, the crystal grains exhibiting an average orientation difference within the crystal grain of 2 degrees or more are complex nitride or composite carbon. A surface-coated cutting tool characterized by being present in an area ratio of 40% or more with respect to the total area of the nitride layer.
2. The composite nitride or composite carbonitride layer is a composite nitride or composite carbonitride layer of Cr and Al, the composition of which is
   Composition formula: (Cr _1-x Al _x ) (C _y N _1-y )
   In the composite nitride or composite carbonitride layer, the average content ratio x _avg in the total amount of Cr and Al in Al and the average content ratio y _avg in the total amount of C and N in C (where x _2. The surface-coated cutting according to claim 1, wherein _avg and y _avg are both atomic ratios) satisfying 0.70 ≦ x _avg ≦ 0.95 and 0 ≦ y _avg ≦ 0.005, respectively. tool.
3. The composite nitride or composite carbonitride layer is composed of Ti, Al, and Me (where Me is a kind of element selected from Si, Zr, B, V, and Cr) or a composite carbonitride. Layer, the composition of which
   Composition formula: (Ti _1-α-β Al _α Me _β ) (C _γ N _1-γ )
   In the composite nitride or composite carbonitride layer, the average content ratio α _avg in the total amount of Ti, Al, and Me of Al, the average content ratio β _avg in the total amount of Me Ti, Al, and Me And the average content ratio γ _avg (where α _avg , β _avg , and γ _avg are atomic ratios) of the total amount of C and N in C and C are 0.60 ≦ α _avg and 0.005 ≦ β _avg , respectively. The surface-coated cutting tool according to claim 1, wherein ≦ 0.10, 0 ≦ γ _avg ≦ 0.005, 0.605 ≦ α _avg + β _avg ≦ 0.95 is satisfied.
4. The composite nitride or composite carbonitride layer is composed of a single phase of composite nitride or composite carbonitride having a NaCl type face-centered cubic structure. The surface-coated cutting tool described.
5. The composite nitride or composite carbonitride layer includes at least 70 area% or more of a composite nitride or composite carbonitride phase having a NaCl-type face-centered cubic structure. The surface-coated cutting tool according to claim 1.
6. Between the tool substrate and the composite nitride or composite carbonitride layer, one or more of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride layer The surface-coated cutting tool according to any one of claims 1 to 5, wherein a lower layer is formed of the Ti compound layer and has a total average layer thickness of 0.1 to 20 µm.
7. 7. The upper layer including at least an aluminum oxide layer is formed on the composite nitride or composite carbonitride layer with a total average layer thickness of 1 to 25 μm. The surface-coated cutting tool according to Item.
8. The surface coating according to any one of claims 1 to 7, wherein the composite nitride or the composite carbonitride layer is formed by a chemical vapor deposition method containing at least trimethylaluminum as a reaction gas component. Cutting tool manufacturing method.

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