JP2016124098A - Surface coated cutting tool excellent in chipping resistance and wear resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface coated cutting tool of which a hard coated layer exhibits excellent chipping resistance and wear resistance in high-speed intermittent cutting conditions.SOLUTION: In a surface coated cutting tool coated with a lower layer of Ti compound layer and an upper layer of TiAlCN layer, such inclination angle number distributions that inclination angles of normals on {422} faces of crystal grain of the Ti compound layer having 1 μm or more and an average layer thickness of 50% or more of the total average layer thickness of the lower layer and crystal grain of the TiAlCN layer of the upper layer for the normal direction of a base body surface fall into the range of 0 to 10° are respectively 30% or more, a TiAlCN crystal grain of which an inclination angle of the normal on {422} face for the normal direction on the base body surface falls into the range of 0 to 10° exists on an area on the upper layer corresponding to the maximum width of the direction parallel to the base body surface of the crystal grain of the Ti compound layer and the crystal grains occupy an area of 50% or more for the total area of TiAlCN crystal grains of which an inclination angle of the normal on {422} face for the normal direction on the base body surface falls into the range of 0 to 10°.SELECTED DRAWING: Figure 1

Description

  The present invention provides an excellent hard coating layer even when cutting various steels and cast irons at high speed and under high-speed intermittent heavy cutting conditions in which intermittent and impactful high loads act on the cutting edge. The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool) that exhibits excellent chipping resistance and wear resistance and exhibits excellent cutting performance over a long period of time.

Conventionally, generally on the surface of a substrate (hereinafter collectively referred to as a tool substrate) composed of a tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet. ,
(A) The lower layer is a Ti carbide (hereinafter referred to as TiC) layer, a nitride (hereinafter also referred to as TiN) layer, a carbonitride (hereinafter referred to as TiCN) layer, a carbon oxide (hereinafter referred to as TiCO). And a Ti compound layer composed of one or more of a carbonitride oxide (hereinafter referred to as TiCNO) layer,
(B) an aluminum oxide layer (hereinafter, referred to as an Al ₂ O ₃ layer) having an α-type crystal structure in a state where the upper layer is chemically vapor-deposited;
There is known a coated tool formed by vapor-depositing a hard coating layer composed of (a) and (b).

However, the above-mentioned conventional coated tools exhibit excellent wear resistance in continuous cutting and intermittent cutting of various steels and cast irons, for example, but when this is used for high-speed intermittent cutting, a hard coating layer is used. Peeling and chipping are likely to occur, and the tool life is shortened.
In view of this, various types of coating tools in which the upper layer is improved have been proposed in order to suppress peeling and chipping of the hard coating layer.

For example, in Patent Document 1, a non-oxide film made of one or more of carbides, nitrides, and carbonitrides of Group 4a, 5a, and 6a metals in the periodic table is formed on the surface of a tool base, and α in the alumina coated tool having an oxide film was formed to a -al ₂ O ₃ as the main, the 4a of the periodic table between the non-oxide layer and the oxide film, 5a, oxides of 6a genus metal oxycarbide, acid An alumina-coated tool that forms a bonding layer having an fcc structure composed of a nitride or oxycarbonitride oxide-based single-layer film or multilayer film, and has a non-oxide film and a binder phase in an epitaxial relationship; Thus, there has been proposed a coated tool that increases the adhesion strength between the tool base and the alumina coating and improves the fracture resistance, peel resistance, and wear resistance.

Further, for example, in Patent Document 2, the surface of a tool base is made of nitride, carbide, carbonitride containing one or more metal elements, and two or more layers having different chemical compositions selected from these are included. In a cutting tool having a laminated hard coating, the composition of the outermost layer on the surface side is (V _u Ti _1-u ) (N _v C _1-v ), where 0.25 ≦ u ≦ 0.75, 0.6 ≦ v ≦ 1, and the composition of the second layer from the surface is (Al _x Ti _1-x ) (N _y C _1-y ), where 0.25 ≦ x ≦ 0.75, 0.6 ≦ y ≦ 1, the thickness of each layer is 0.4 μm or more, the thickness of the entire film is 0.8 to 50 μm, and each layer substantially has a rock salt type crystal structure, and The crystal structure of each layer is substantially epitaxially grown at the interface, improving the wear resistance and adhesion of the hard coating. Has been proposed.

JP-A-10-18039 JP 2001-181826 A

  In recent years, the performance of cutting machines has been remarkable. On the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting work. As a result, cutting speed has been further increased, high cutting depth, high feed, etc. There is a tendency for impact and intermittent high loads to act on the cutting edge due to intermittent heavy cutting, etc., but in the above-mentioned conventional coated tools, this is continuous cutting under normal conditions such as steel and cast iron. There is no problem when it is used for intermittent cutting, but especially when this is used under high-speed intermittent cutting conditions, the wear resistance of the hard coating layer is not sufficient, so the service life is reached in a relatively short time. is the current situation.

In view of the above, the inventors of the present invention, from the above-mentioned viewpoints, made Ti compound crystal grains constituting the lower layer formed on the surface of the tool substrate and a composite nitride of Ti and Al constituting the upper layer formed thereon. Or, intensive research to improve the chipping resistance and wear resistance of the hard coating layer as a whole by controlling the epitaxial relationship between the crystal grains of the composite carbonitride (hereinafter abbreviated as TiAlCN in some cases). Repeated.
as a result,
(1) Ti having an average layer thickness of 50% or more of the total average layer thickness of the lower layer, and having a crystal structure of NaCl-type face-centered cubic (hereinafter sometimes referred to simply as “cubic”) The crystal grains of the compound layer (preferably, the Ti carbonitride (hereinafter sometimes referred to as “TiCN”) layer) and the crystal grains of the TiAlCN layer constituting the upper layer are {422 }, When the frequency distribution of the inclination angle formed by the normal line to the normal direction of the substrate surface is measured, a frequency peak exists in the inclination angle division of 0 to 10 degrees with respect to the normal direction, and the division The inclination angle number distribution ratio of is 30% or more of the entire frequency,
(2) The crystal grains of a Ti compound layer (preferably a Ti carbonitride (TiCN) layer) having an average layer thickness of 50% or more of the total average layer thickness of the lower layer and having a cubic structure Of these, in the region of the upper layer corresponding to the maximum width in the direction parallel to the substrate surface of the crystal grains whose inclination angle formed by the normal direction of the substrate surface and the normal of {422} is 0 to 10 degrees, {422} TiAlCN crystal grains having an inclination angle of 0 to 10 degrees with the normal direction of the substrate surface and the normal direction of {422} are the same as the normal direction of the substrate surface. By forming 50% or more of the TiAlCN crystal grains having an inclination angle of 0 to 10 degrees, the formation ratio of the epitaxially grown crystal grains of the lower layer and the upper layer is increased, and the normal direction of the substrate surface and {422} The shape of crystal grains whose inclination angle is 0 to 10 degrees By increasing the ratio, the hardness and adhesion strength between the lower layer and the upper layer are improved, and the hard coating is applied even in high-speed intermittent cutting conditions where the cutting blade is subjected to intermittent and impactful high loads at high speed. It has been found that the layer has excellent adhesion strength and exhibits excellent chipping resistance and wear resistance.

The present invention has been made based on the above findings,
“(1) Hard coating comprising a lower layer and an upper layer on the surface of a tool base made of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh pressure sintered body In a surface-coated cutting tool in which a layer is formed,
(A) The lower layer has a total average layer thickness of 1 to 20 μm comprising one or more of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride layer. And one of them is a Ti compound layer having an average layer thickness of 1 μm or more and 50% or more of the total average layer thickness,
(B) The upper layer is a composite nitride or composite carbonitride layer of Ti and Al having an average layer thickness of 1 to 20 μm,
(C) the Ti and Al composite nitride or composite carbonitride layer,
Composition formula: (Ti _1-x Al _x ) (C _y N _1-y )
The average content ratio X _ave in the total amount of Ti and Al in Al and the average content ratio Y _ave in the total amount of C and N in C (where X _ave and Y _ave are atomic ratios) Satisfy 0.60 ≦ X _ave ≦ 0.95 and 0 ≦ Y _ave ≦ 0.005,
(D) Among the lower layers, the crystal grains of the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness have a crystal structure of NaCl type face centered cubic crystal, and Ti of the upper layer The crystal grains of the composite nitride or composite carbonitride layer of Al and Al have a crystal structure composed of a single phase of the NaCl type face centered cubic structure or a mixed phase of the NaCl type face centered cubic structure and a hexagonal structure,
(E) Ti and Al composite nitride or composite carbonitride having a crystal grain of a Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness of the lower layer and the cubic structure of the upper layer When the crystal orientation of each crystal grain of the physical layer is analyzed from the longitudinal cross-sectional direction using an electron beam backscattering diffractometer, the method of the {422} plane which is the crystal plane of the crystal grain with respect to the normal direction of the substrate surface The inclination angle formed by the line is measured, and among the measurement inclination angles, the measurement inclination angles within the range of 0 to 45 degrees with respect to the normal direction of the substrate surface are divided for each pitch of 0.25 degrees. When the frequencies existing in the section are counted, the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness of the lower layer and the composite nitriding of Ti and Al having the cubic structure of the upper layer In either the product or the composite carbonitride layer, 0 to With the highest peak is present in the tilt angle sections of the range of 0 degrees, the sum of the frequencies present in the range of the 0 to 10 degrees, indicates the percentage of more than 30% of the total power at the inclination angle frequency distribution,
(F) In the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness among the lower layers, the inclination angle of the normal of the {422} plane with respect to the normal direction of the substrate surface is 0 to 10 degrees. In the region of the upper layer corresponding to the maximum width of the crystal grains in the direction parallel to the substrate surface, the inclination angle of the normal of the {422} plane with respect to the normal direction of the substrate surface is in the range of 0 to 10 degrees. And a crystal grain of the Ti and Al composite nitride or composite carbonitride layer having the cubic crystal structure, and the crystal grain is normal to the {422} plane with respect to the normal direction of the substrate surface The Ti and Al composite nitride or composite carbonitride layer having a cubic structure having an inclination angle of 0 to 10 degrees occupies an area ratio of 50% or more of the entire crystal grain area. A surface-coated cutting tool.
(2) The surface-coated cutting tool according to (1), wherein the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness of the lower layer is a Ti carbonitride layer. .
(3) An outermost surface layer including at least an aluminum oxide layer having an average layer thickness of 1 to 25 μm is further formed on the surface of the upper layer composed of the composite nitride or composite carbonitride layer of Ti and Al. The surface-coated cutting tool according to (1) or (2), wherein "
It has the characteristics.

  Below, the structural layer of the hard coating layer of the coating tool of this invention is demonstrated in detail.

FIG. 1 shows a schematic diagram of the layer structure of the hard coating layer of the present invention. In FIG. 1, the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness of the lower layer is cubic. A TiCN layer having a crystal structure is formed, and an upper layer made of a TiAlCN layer is formed thereon.
As can be seen from FIG. 1, a crystal structure form in which crystal grains grow through the interface is observed at the interface between the upper layer and the lower layer.
In the present invention, “the crystal grains of the lower layer and the crystal grains of the upper layer are epitaxially grown in the normal direction of the {422} plane” refers to such a crystal structure form.

Lower layer (Ti compound layer):
Ti compound layers (eg, Ti carbide (TiC) layer, nitride (TiN) layer, carbonitride (TiCN) layer, carbonate (TiCO) layer and carbonitride oxide (TiCNO) layer) are basically Exists as a lower layer of the TiAlCN layer, and the hard coating layer has a high temperature strength due to its excellent high temperature strength. In addition, the hard coating layer adheres to both the tool base and the upper TiAlCN layer. It has the effect | action which maintains the adhesiveness with respect to a tool base | substrate. However, if the total average layer thickness is less than 1 μm, the above-mentioned effect cannot be sufficiently exerted. On the other hand, if the total average layer thickness exceeds 20 μm, the thermoplastic deformation is caused particularly in high-speed intermittent cutting with high heat generation. The total average layer thickness is determined to be 1 to 20 μm because it tends to occur and causes uneven wear.
Furthermore, in order to epitaxially grow the upper layer by taking over the {422} orientation of the lower layer and improve the adhesion strength of the hard coating layer, the lower layer has at least a cubic structure and an average layer thickness of 1 μm or more. And a Ti compound layer (for example, Ti carbide layer, nitride layer, carbonitride layer, carbonitride oxide layer) having an average layer thickness of 50% or more of the total average layer thickness of the lower layer. ) Crystal grains are required to have {422} orientation. In addition, when the average layer thickness of the Ti compound layer having {422} orientation is less than 1 μm or less than 50% of the total average layer thickness of the lower layer, the {422} orientation of the lower layer is inherited. The epitaxial growth of the upper layer becomes insufficient, and the adhesion strength cannot be improved together with the chipping resistance of the upper layer.

As the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness of the lower layer, it is preferable to form a TiCN layer made of TiCN crystal grains.
For example, a lower TiCN layer having {422} orientation is formed by using a normal chemical vapor deposition apparatus, for example,
Reaction gas composition (volume%): TiCl ₄ 2.0-2.5%, N ₂ 5-10%, CO 0-2%, CH ₃ CN 0.4-0.6%, balance H ₂ ,
Reaction atmosphere temperature: 750 to 800 ° C.
Reaction atmosphere pressure: 5 to 10 kPa,
It can form by carrying out chemical vapor deposition until it becomes target average layer thickness on the conditions of.

Upper layer (TiAlCN layer having a single crystal structure of cubic structure or a mixed crystal structure of cubic structure and hexagonal structure):
The upper layer of the hard coating layer of the present invention is a TiAlCN layer having a cubic single crystal structure having a mean layer thickness of 1 to 20 μm or a mixed crystal structure of a cubic structure and a hexagonal structure, which is chemically deposited.
Since the TiAlCN layer constituting the upper layer of the present invention has {422} orientation, it has high hardness and excellent wear resistance. However, if the average layer thickness is less than 1 μm, the layer thickness is thin. However, if the average layer thickness exceeds 20 μm, the crystal grains become coarse and chipping is likely to occur.
Therefore, the average layer thickness of the TiAlCN layer constituting the upper layer is determined to be 1 to 20 μm.
The upper layer may be a TiAlCN layer composed of a mixed phase of a cubic structure and a hexagonal structure as well as a cubic structure single layer.

When the TiAlCN layer constituting the upper layer of the present invention is expressed by a composition formula: (Ti _1-x Al _x ) (N _1-y C _y ), the average content ratio X of the total amount of Ti and Al in Al _The content ratio Y _ave (where X _ave and Y _ave are atomic ratios) in the total amount of C and N in _ave and C are 0.60 ≦ X _ave ≦ 0.95 and 0 ≦ Y _ave ≦, respectively. 0.005 is satisfied.
Here, when the average content ratio X _ave (atomic ratio) of Al is less than 0.60, the composite nitride or composite carbonitride layer of Ti and Al is inferior in hardness, so high-speed intermittent cutting of alloy steel or the like When it is used, the wear resistance is not sufficient. On the other hand, when the average content ratio _{Xave of} Al exceeds 0.95, the content ratio of Ti is relatively decreased, so that embrittlement is caused and chipping resistance is deteriorated.
Therefore, the average content ratio X _ave (atomic ratio) of Al is set to 0.60 ≦ X _ave ≦ 0.95.
Further, when the average content ratio (atomic ratio) Y _ave of the C component contained in the composite nitride or composite carbonitride layer is a minute amount in the range of 0 ≦ Y _ave ≦ 0.005, the upper layer and the lower layer As a result, the impact at the time of cutting is reduced by improving the lubricity, and as a result, the chipping resistance and chipping resistance of the composite nitride or composite carbonitride layer are improved. On the other hand, if the content ratio Y _ave of the C component is out of the range of 0 ≦ Y _ave ≦ 0.005, the toughness of the composite nitride or the composite carbonitride layer is lowered, so that the chipping resistance and chipping resistance are reduced. To do.
Therefore, the content ratio Y _ave (atomic ratio) of the C component is 0 ≦ Y _ave ≦ 0.005.

Tilt angle number distribution about {422} planes of crystal grains of the lower layer and the upper layer:
Electron beam backscattering with respect to the crystal orientation of individual crystal grains of the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness of the lower layer of the present invention and the TiAlCN layer having a cubic structure of the upper layer When analyzed from the longitudinal section direction using a diffractometer, the normal of the {422} plane which is the crystal plane of the crystal grain with respect to the normal of the tool base surface (direction perpendicular to the tool base surface in the cross-section polished surface) Measures the inclination angle formed by, and among the inclination angles, the inclination angle within the range of 0 to 45 degrees with respect to the normal direction is divided into pitches of 0.25 degrees and the frequency existing in each division The maximum peak is present in the inclination angle section within the range of 0 to 10 degrees, and the total of the frequencies existing within the range of 0 to 10 degrees is 30% of the entire frequency in the inclination angle frequency distribution. Inclination angle number distribution form with the above ratio It is necessary to show.
Here, in either the lower layer or the upper layer, if the inclination angle number distribution with respect to the {422} plane is out of the above range, the {422} plane orientation as the entire hard coating layer is lowered, and the hardness is reduced. Abrasion resistance is impaired by lowering.
Further, in order to promote the epitaxial growth of the lower layer and the upper layer in addition to the {422} plane orientation of each of the lower layer and the upper layer, a Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness In the region of the upper layer corresponding to the maximum width in the direction parallel to the substrate surface of the crystal grains whose inclination angle of the normal of the {422} plane with respect to the normal direction of the substrate surface is in the range of 0 to 10 degrees, There are crystal grains of the TiAlCN layer having the cubic structure in which the inclination angle of the normal of the {422} plane with respect to the normal direction of the substrate surface is in the range of 0 to 10 degrees, and the TiAlCN crystal grains are An area ratio of 50% or more of the total area of the crystal grains of the TiAlCN layer having the cubic structure in which the inclination angle of the normal of the {422} plane with respect to the normal direction of the substrate surface is in the range of 0 to 10 degrees. Need to occupy That.
That is, when the area ratio of the TiAlCN crystal grains epitaxially grown between the lower layer and the upper layer is less than 50% of the entire crystal grains of the TiAlCN layer having a cubic structure, the epitaxial growth is not sufficient. This is because the adhesion strength between the lower layer and the upper layer cannot be improved, and abnormal damage such as peeling tends to occur in high-speed intermittent cutting.
By promoting the epitaxial growth of grains having the {422} plane orientation of the lower layer and the {422} plane orientation of the upper layer as defined in the present invention, and the {422} plane orientation between the lower layer and the upper layer, The adhesion strength between the lower layer and the upper layer is improved, and the hardness of the entire hard coating layer is improved.
As a result, even when such a coated tool is used for, for example, high-speed intermittent cutting of alloy steel, the occurrence of chipping, peeling and the like is suppressed, and excellent wear resistance is exhibited.
FIG. 2 and FIG. 3 show an example of the inclination angle number distribution obtained for the lower layer and the upper layer of the present invention. FIG. 2 shows an average layer thickness of 50% or more of the total average layer thickness of the lower layer of the present invention. FIG. 3 is a graph obtained for the cubic TiAlCN crystal grains of the upper layer.

Outermost layer:
In the present invention, an oxide having an average layer thickness of 1 to 25 μm is formed on the surface of an upper layer composed of a TiAlCN layer having a cubic single-phase crystal structure or a cubic and hexagonal crystal structure having an average layer thickness of 1 to 20 μm. An outermost surface layer including at least an aluminum layer can be further formed.
The aluminum oxide layer of the outermost surface layer increases the high temperature hardness and heat resistance of the hard coating layer. However, if the average layer thickness of the outermost surface layer is less than 1 μm, the hard coating layer cannot be sufficiently provided with the above characteristics. If the average layer thickness exceeds 25 μm, the high heat generated during cutting and the intermittent and impactful high load acting on the cutting blade are likely to cause thermoplastic deformation causing uneven wear, which accelerates wear. Therefore, the average layer thickness is desirably 1 to 25 μm.

Deposition method:
The lower layer and the outermost layer of the present invention can be formed by, for example, a normal chemical vapor deposition method and apparatus.
For example, when forming a TiC layer, TiN layer, TiCN layer, etc. as a Ti compound layer having an average layer thickness of 1 μm or more and an average layer thickness of 50% or more of the total average layer thickness of the lower layer, Using chemical vapor deposition equipment
Reaction gas composition (volume%): TiCl ₄ 2-2.5%, N ₂ 5-10%, CO 0-2%, CH ₃ CN 0.4-0.6%, balance H ₂
Reaction atmosphere temperature: 750 to 800 ° C.
Reaction atmosphere pressure: 5 to 10 kPa,
By performing chemical vapor deposition until the target average layer thickness is reached under the above conditions, a TiC layer, a TiN layer, a TiCN layer, or the like having {422} plane orientation can be formed.
The upper layer can also be formed by a normal chemical vapor deposition method, but can also be formed by, for example, the following vapor deposition method.
That is, a gas group A composed of NH ₃ and H ₂ and a gas group B composed of TiCl ₄ , AlCl ₃ , NH ₃ , N ₂ , C ₂ H ₄ , and H ₂ are applied to a chemical vapor deposition reactor equipped with a tool base. The reaction gas composition on the surface of the tool base is controlled by adjusting the supply conditions of the gas group A and the gas group B, and the reaction atmosphere pressure is 2 to 5 kPa, the reaction atmosphere. By performing the thermal CVD method at a temperature of 700 to 900 ° C. for a predetermined time, a TiAlCN layer having a predetermined target layer thickness and target composition can be formed.

  The coated tool of the present invention has an average layer thickness of 50% or more of the total average layer thickness of the lower layer, and the normal of the {422} plane of the crystal grain of the Ti compound layer having a cubic structure and the substrate surface The tilt angle distribution with the tilt angle with the normal direction is 30% or more, and the TiAlCN crystal grains having the cubic structure of the upper layer also have the {422} plane. An inclination angle number distribution in which the inclination angle between the normal line of the substrate and the normal direction of the substrate surface is in the range of 0 to 10 degrees is 30% or more, and the average is 50% or more of the total average layer thickness of the lower layers. The tilt ratio between the area ratio of the {422} plane of the crystal grains of the Ti compound layer having a layer thickness and the cubic structure and the TiAlCN crystal grains of the upper layer epitaxially grown with respect to the normal direction of the substrate surface is 0 More than 50% of the entire TiAlCN crystal grains of -10 degrees As a result, the hardness of the lower layer and the upper layer is improved, and the adhesion strength between the lower layer and the upper layer is improved. As a result, the cutting blade is subjected to high loads at high speed and intermittently and shockingly. Even under high-speed intermittent cutting conditions, the hard coating layer exhibits excellent chipping resistance and also exhibits excellent wear resistance over a long period of use.

The schematic model of the layer structure of the hard coating layer of this invention is shown. 1 shows an example of a graph obtained for TiCN crystal grains having a cubic structure having an average layer thickness of 50% or more of the total average layer thickness of the lower layer in the distribution of inclination angle numbers obtained for the lower layer and the upper layer of the present invention. . An example of the graph calculated | required about the TiAlCN crystal grain of the cubic structure of the upper layer among the inclination angle number distribution calculated | required about the lower layer and the upper layer of this invention is shown.

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

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 at a predetermined temperature within a range of ˜1470 ° C. for 1 hour, and after sintering, manufacture tool bases A to C made of WC-base cemented carbide with ISO standard SEEN1203AFSN insert shape, respectively. did.

In addition, as raw material powders, all TiCN (mass ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, WC powder, Co powder 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,
First, under the formation conditions shown in Table 3, the lower layer shown in Table 7 is formed,
Next, the formation conditions A to J shown in Tables 5 and 6, that is, from the gas group A composed of NH ₃ and H ₂ , TiCl ₄ , AlCl ₃ , NH ₃ , N ₂ , C ₂ H ₄ , H ₂ As a gas group B and a gas supply method, the reaction gas composition (capacity% with respect to the total of the gas group A and the gas group B) is set to NH ₃ : 1.5 to 3.0% as the gas group A. , H ₂ : 50 to 75%, gas group B as TiCl ₄ : 0.1 to 0.15%, AlCl ₃ : 0.3 to 0.5%, N ₂ : 0 to 2%, C ₂ H ₄ : 0 to 0.05%, H ₂ : remaining, reaction atmosphere pressure: 2 to 5 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, the phase difference between gas supply A and gas supply B is 0.10 to 0.20 seconds, In the meantime, this invention coated tool 1-10 was produced by performing a thermal CVD method and forming an upper layer.
In addition, about this invention coated tools 8-10, the upper layer shown in Table 7 was formed on the formation conditions shown in Table 3.

For comparison purposes, the lower layers shown in Table 8 are formed on the surfaces of the tool bases A to D using the normal chemical vapor deposition apparatus under the formation conditions shown in Table 4, and Tables 5 and 6 show the results. A hard coating layer including at least a composite nitride or composite carbonitride layer of Ti and Al was formed by vapor deposition in the same manner as in the present invention coated tools 1 to 10 under the conditions shown and the target layer thickness (μm) shown in Table 8. .
In addition, about the comparison coating tools 8-10, the upper layer shown by Table 8 was formed on the formation conditions shown by Table 4 similarly to this invention coating tools 8-10.

  The cross sections in the direction perpendicular to the tool substrate of each constituent layer of the inventive coated tools 1 to 10 and comparative coated tools 1 to 10 were measured using a scanning electron microscope (magnification 5000 times), and 5 points in the observation field of view. The average layer thickness was measured and averaged to obtain the average layer thickness. As a result, the average layer thickness was substantially the same as the target layer thickness shown in Tables 7 and 8.

Also, the average content X _ave of Al TiAlCN layer of the upper layer, electron microprobe (Electron-Probe-Micro-Analyser : EPMA) using, in samples polished surface, an electron beam from the sample surface side Irradiation was performed, and the average content ratio _Xave of Al was determined from the average of 10 points of the analysis result of the obtained characteristic X-rays.
Moreover, about average content ratio _Yave of C, it calculated | required 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 content ratio Y _ave of C indicates the average value in the depth direction for the TiAlCN layer. 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 TiAlCN layer when the supply amount of C ₂ H ₄ is 0 is determined as an unavoidable C content ratio, and C ₂ H ₄ is intentionally determined. A value obtained by subtracting the unavoidable C content from the content (atom ratio) of the C component contained in the TiAlCN layer obtained when supplied was determined as Y _ave .

In addition, regarding the distribution of the inclination angle number of the hard coating layer, first, field emission is performed with the cross section of the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness of the lower layer as a polished surface. Set in a lens barrel of a scanning electron microscope, an electron beam with an acceleration voltage of 10 kV at an incident angle of 70 degrees and an irradiation current of 1 nA, a measurement range of 1 μm in the direction perpendicular to the tool substrate surface, and the tool substrate surface In the horizontal direction, the crystal grains having a cubic crystal structure existing in the measurement range are irradiated at intervals of 0.1 μm / step over a range of 50 μm, and a tool is used by using an electron beam backscatter diffraction image apparatus. The inclination angle formed by the normal of the {422} plane, which is the crystal plane of the crystal grain, is measured with respect to the normal of the base surface (the direction perpendicular to the tool base surface on the cross-section polished surface). The angle of measurement In addition to dividing the measured inclination angle within the range of 0 to 45 degrees into every 0.25 degree pitch, and calculating the inclination angle classification where the highest peak exists by counting the frequencies existing in each division The ratio of the frequency existing in the range of 0 to 10 degrees was determined.
Tables 7 and 8 show the results.

Next, with regard to the distribution of the number of inclination angles of the upper layer of the hard coating layer, it is set in a lens barrel of a field emission scanning electron microscope with the cross section of the upper layer being a polished surface, and 10 kV at an incident angle of 70 degrees. An electron beam with an acceleration voltage of 1 nA and an irradiation current of 1 nA, a measurement range of 0.5 μm in the direction perpendicular to the tool substrate surface, and a spacing of 0.1 μm / step over a range of 100 μm in the horizontal direction from the tool substrate surface Then, each crystal grain having a cubic crystal structure existing within the measurement range is irradiated, and the normal of the tool base surface (direction perpendicular to the tool base surface on the cross-section polished surface) is obtained using an electron backscatter diffraction image apparatus. In contrast, the inclination angle formed by the normal of the {422} plane, which is the crystal plane of the crystal grain, is measured, and based on the measurement result, the measurement inclination angle is in the range of 0 to 45 degrees. Measurement pitch is 0.25 degree pitch With partitioning, by aggregating the frequencies present in each segment, along with determining the tilt angle sections highest peak is present, to determine the percentage of power that exists in the range of 0 degrees.
Tables 7 and 8 show the results.

In addition, regarding the crystal grains of the Ti compound layer and the TiAlCN crystal grains of the upper layer having an average layer thickness of 50% or more of the total average layer thickness of the lower layer of the hard coating layer, individual crystals are obtained using a field emission scanning electron microscope. Analyzing the crystal orientation of the grains, measuring the inclination angle formed by the normal of the {422} plane of each crystal grain with respect to the normal of the tool substrate surface, and measuring an average layer of 50% or more of the total average layer thickness of the lower layer In the region of the upper layer corresponding to the maximum width of the crystal grain in the direction parallel to the substrate surface in the Ti compound layer having a thickness, the inclination angle of the normal of the {422} plane with respect to the normal direction of the substrate surface is 0-10. There is a crystal grain of a composite nitride or composite carbonitride layer of Ti and Al having the cubic structure within a range of degrees, and the crystal grain is a {422} plane with respect to the normal direction of the substrate surface The angle of inclination of the normal is in the range of 0-10 degrees It determines whether corresponding occupy an area percentage of 50% or more of crystal grains whole area of Ti and complex nitrides of Al or composite carbonitride layer having a cubic structure is within.
That is, for the inventive coated tools 1-10 and comparative coated tools 1-10, an average layer thickness of 50% or more of the total average layer thickness of the lower layer in the thickness direction of the lower layer from the interface between the upper layer and the lower layer. A measurement range (2.0 μm or more × 50 μm) of a cross-section polished surface of 1.0 μm in the thickness direction of the upper layer and 1.0 μm in the thickness direction of the upper layer and 50 μm in the direction parallel to the tool base surface. Set in a lens barrel of a field emission scanning electron microscope, and an electron beam with an acceleration voltage of 15 kV at an incident angle of 70 degrees on the polished surface is present in the measurement range of each polished surface with an irradiation current of 1 nA Irradiate each individual crystal grain having a cubic crystal lattice, and use an electron backscatter diffraction image apparatus to set a measurement area of 2.0 to 50 μm at a normal of the tool base surface at an interval of 0.1 μm / step. In contrast, the crystal plane of the crystal grain The inclination angle formed by the normal of the {422} plane is measured, and the maximum width in the direction parallel to the substrate surface of the crystal grains in the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness of the lower layer In the corresponding upper layer region, Ti and Al composite nitride or composite having the cubic structure in which the inclination angle of the normal of the {422} plane with respect to the normal direction of the substrate surface is in the range of 0 to 10 degrees The epitaxial relationship defined in the present invention is confirmed by the presence of crystal grains of the carbonitride layer, and the crystal grains are in the normal direction of the substrate surface in the measurement region of 2.0 to 50 μm. 50% or more of the total crystal grain area of the Ti and Al composite nitride or composite carbonitride layer having the cubic structure in which the inclination angle of the normal of the {422} plane is in the range of 0 to 10 degrees To occupy the area ratio of It determines whether or not specified in.
Further, the measurement by the electron backscattering analyzer confirmed that the lower layer was cubic, and that the TiAlCN of the upper layer was cubic or a mixture of cubic and hexagonal.
Tables 7 and 8 show these values.

  Next, the present coated tools 1 to 10 and the comparative coated tools 1 to 10 are described below in a state where the various coated tools are all clamped to a tool steel cutter tip portion having a cutter diameter of 125 mm by a fixing jig. The dry high-speed face milling, which is a kind of high-speed interrupted cutting of alloy steel, and a center-cut cutting test were performed, and the flank wear width of the cutting blade was measured. The results are shown in Table 9.

Tool substrate: Tungsten carbide-based cemented carbide, titanium carbonitride-based cermet,
Cutting test: dry high-speed face milling, center cutting,
Work material: JIS / SCM440 block material with a width of 100 mm and a length of 400 mm,
Rotational speed: 980 min ⁻¹
Cutting speed: 385 m / min,
Cutting depth: 1.5 mm,
Single-blade feed rate: 0.15 mm / tooth,
Cutting time: 8 minutes

As raw material powders, WC powder, TiC powder, ZrC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder and Co powder all 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 honing processing with an R of 0.07 mm. Tool bases E to G made of a WC-base cemented carbide having an insert shape of CNMG12041 were manufactured.

  In addition, as raw material powder, TiCN (mass ratio TiC / TiN = 50/50) powder, NbC powder, WC powder, Co powder, and Ni powder all 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 tool substrate H made of cermet was formed.

Next, a chemical vapor deposition apparatus is used on the surfaces of the tool bases E to G and the tool base H, and at least (Ti _{1) under the} conditions shown in Tables 3, 5 and 6 by the same method as in Example _{1. -x} Al _{x) (by} C _{y N 1-y)} layer is deposited formed at the target layer thickness of the hard coating layer containing was prepared present invention coated tool 11 to 20 shown in Table 12.
In addition, about this invention coated tools 18-20, the upper layer as shown in Table 12 was formed on the formation conditions shown in Table 3.

Further, for the purpose of comparison, a normal chemical vapor deposition apparatus was used on the surfaces of the tool bases E to G and the tool base H, and the conditions shown in Tables 4, 5 and 6 and the target layer thicknesses shown in Table 13 were used. Thus, comparative coated tools 11 to 20 shown in Table 13 were produced by vapor-depositing a hard coating layer in the same manner as the coated tool of the present invention.
In addition, similarly to this invention coated tool 18-20, about comparative coated tool 18-20, the upper layer shown in Table 13 was formed on the formation conditions shown in Table 4.

  The cross-section of each component layer of the present coated tool 11-20 and comparative coated tool 11-20 is measured using a scanning electron microscope (5000 times magnification), and the layer thicknesses at five points in the observation field are measured and averaged. As a result, the average layer thickness was found to be substantially the same as the target layer thickness shown in Tables 12 and 13.

The average Al content ratio X _ave and the average C content ratio Y _ave of the upper TiAlCN layer were determined in the same manner as in Example 1 using an electron beam microanalyzer (Electron-Probe-Micro-Analyzer: EPMA). .
In addition, regarding the tilt angle and the tilt angle number distribution formed by the normal of the {422} plane of the crystal grains having the cubic crystal structure of the lower layer and the upper layer of the hard coating layer with respect to the normal of the tool substrate surface, Determined in the same manner as in Example 1.
Further, the area ratio of the TiAlCN crystal grains in the upper layer epitaxially growing in the normal direction of the {422} plane of the crystal grains in the lower layer adjacent to each other through the interface is obtained in the same manner as in Example 1. It was.
Tables 12 and 13 show these values.

Next, the present invention coated tools 11 to 20 and comparative coated tools 11 to 20 are shown below in a state where all of 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 · S45C lengthwise equal 4 round grooved round bars,
Cutting speed: 390 m / min,
Cutting depth: 1.0 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,
Cutting depth: 1.5 mm,
Feed: 0.1 mm / rev,
Cutting time: 5 minutes,
(Normal cutting speed is 200 m / min),
Table 14 shows the results of the cutting test.

As the raw material powder, cBN powder, TiN powder, TiC powder, Al powder, and Al ₂ O ₃ powder each having an average particle diameter in the range of 0.5 to 4 μm are prepared. These raw material powders are shown in Table 15. After blending into the blended composition, wet mixing with a ball mill for 80 hours, drying, and press-molding into a green compact with a diameter of 50 mm × thickness: 1.5 mm at a pressure of 120 MPa, and then this green compact Is sintered in a vacuum atmosphere at a pressure of 1 Pa at a predetermined temperature in the range of 900 to 1300 ° C. for 60 minutes to obtain a presintered body for a cutting edge piece, and this presintered body is separately prepared. A normal ultra high pressure sintering apparatus in a state of being superposed on a support piece made of WC base cemented carbide having Co: 8 mass%, WC: remaining composition, and diameter: 50 mm × thickness: 2 mm Normal pressure: 4 Pa, temperature: prestressed at a predetermined temperature in the range of 1200 to 1400 ° C., holding time: 0.8 hours, and after sintering, the upper and lower surfaces are polished using a diamond grindstone, and the wire electric discharge machine Then, it is divided into predetermined dimensions, and Co: 5 mass%, TaC: 5 mass%, WC: remaining composition and shape of JIS standard CNGA120212 (thickness: 4.76 mm × inscribed circle diameter: 12.7 mm 80) Ti- having a composition consisting of Zr: 37.5%, Cu: 25%, Ti: the remainder in the brazing part (corner part) of the insert body made of WC-based cemented carbide with a diamond) After brazing using a brazing material of Zr-Cu alloy and processing the outer periphery to a predetermined dimension, the cutting edge is subjected to honing processing with a width of 0.13 mm and an angle of 25 °, and further subjected to final polishing to achieve ISO. Standard CNGA12 Tool substrate b having a 412 insert shape, The filtrate was produced, respectively.

Next, a lower layer shown in Table 16 is formed on the surface of these tool bases (a) and (b) using a chemical vapor deposition apparatus, under the formation conditions shown in Table 3, as in Example 1, Under the conditions shown in Table 6, the present invention coated tools 21 to 26 were produced by performing the thermal CVD method for a predetermined time to form the upper layer.
In addition, about this invention coated tools 25-26, the upper layer shown in Table 16 was formed on the formation conditions shown in Table 3.

For comparison purposes, the lower layers shown in Table 17 are formed on the surfaces of the tool bases (a) and (b) using the usual chemical vapor deposition apparatus under the formation conditions shown in Table 4, and Tables 5 and 6 are used. Comparative coating tools 21 to 26 were produced by forming the upper layer by performing the thermal CVD method for a predetermined time under the conditions shown in FIG.
In addition, about the comparison coating tools 25-26, the upper layer shown in Table 17 was formed on the formation conditions shown in Table 4.

  Moreover, the cross section of this invention coating tool 21-26 and the comparison coating tool 21-26 was measured using the scanning electron microscope, the layer thickness of five points in an observation visual field was measured, and it averaged and calculated | required the average layer thickness. .

The average Al content ratio X _ave and the average C content ratio Y _ave of the upper TiAlCN layer were determined in the same manner as Example 1 using an electron beam microanalyzer (Electron-Probe-Micro-Analyzer: EPMA). .
In addition, regarding the tilt angle and the tilt angle number distribution formed by the normal of the {422} plane of the crystal grains having the cubic crystal structure of the lower layer and the upper layer of the hard coating layer with respect to the normal of the tool substrate surface, Determined in the same manner as in Example 1.
Further, the area ratio of the TiAlCN crystal grains in the upper layer epitaxially growing in the normal direction of the {422} plane of the crystal grains in the lower layer adjacent to each other through the interface is obtained in the same manner as in Example 1. It was.
Tables 16 and 17 show these values.

Next, the present invention coated tools 21 to 26 and comparative coated tools 21 to 26 are shown below in a state where any of the various coated tools is screwed to the tip of the tool steel tool with a fixing jig. Then, a dry high-speed intermittent cutting test of carburized and hardened alloy steel was performed, and the flank wear width of the cutting edge was measured.
Work material: JIS · SCr420 (Hardness: HRC62) lengthwise equidistant four round bars with vertical grooves,
Cutting speed: 255 m / min,
Cutting depth: 0.10 mm,
Feed: 0.12 mm / rev,
Cutting time: 4 minutes
Table 18 shows the results of the cutting test.

From the results shown in Tables 7 to 9, 12 to 14, and 16 to 18, the coated tools 1 to 26 of the present invention show the {422} orientation of the lower layer adjacent through the interface and the {422} of the upper layer. } Epitaxial growth of TiAlCN crystal grains exhibiting orientation improves adhesion density at the interface, and at the same time, the hard coating layer has high hardness, resulting in high heat generation and intermittent / impact on the cutting edge. Even when used in high-speed intermittent cutting conditions where a high load is applied, the hard coating layer has excellent chipping resistance and excellent wear resistance over a long period of use.
On the other hand, in the comparative coated tools 1 to 26, in high-speed intermittent cutting, the service life is shortened in a relatively short time due to occurrence of abnormal damage such as chipping, chipping and peeling of the hard coating layer and a decrease in wear resistance. It is clear that

  The coated tool of the present invention has severe cutting conditions such as high-speed intermittent cutting in which high loads such as intermittent and impact loads are applied to the cutting blade as well as continuous cutting and intermittent cutting under normal conditions such as various steels and cast iron. Excellent chipping resistance and wear resistance can be exhibited even under low conditions, so that it is possible to satisfactorily respond to higher performance of cutting equipment, labor saving and energy saving of cutting, and lower costs. .

Claims (3)

A hard coating layer consisting of a lower layer and an upper layer is formed on the surface of the tool base made of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh-pressure sintered body. Surface coated cutting tools
(A) The lower layer has a total average layer thickness of 1 to 20 μm comprising one or more of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride layer. And one of them is a Ti compound layer having an average layer thickness of 1 μm or more and 50% or more of the total average layer thickness,
(B) The upper layer is a composite nitride or composite carbonitride layer of Ti and Al having an average layer thickness of 1 to 20 μm,
(C) the Ti and Al composite nitride or composite carbonitride layer,
Composition formula: (Ti _1-x Al _x ) (C _y N _1-y )
The average content ratio X _ave in the total amount of Ti and Al in Al and the average content ratio Y _ave in the total amount of C and N in C (where X _ave and Y _ave are atomic ratios) Satisfy 0.60 ≦ X _ave ≦ 0.95 and 0 ≦ Y _ave ≦ 0.005,
(D) Among the lower layers, the crystal grains of the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness have a crystal structure of NaCl type face centered cubic crystal, and Ti of the upper layer The crystal grains of the composite nitride or composite carbonitride layer of Al and Al have a crystal structure composed of a single phase of the NaCl type face centered cubic structure or a mixed phase of the NaCl type face centered cubic structure and a hexagonal structure,
(E) Ti and Al composite nitride or composite carbonitride having a crystal grain of a Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness of the lower layer and the cubic structure of the upper layer When the crystal orientation of each crystal grain of the physical layer is analyzed from the longitudinal cross-sectional direction using an electron beam backscattering diffractometer, the method of the {422} plane which is the crystal plane of the crystal grain with respect to the normal direction of the substrate surface The inclination angle formed by the line is measured, and among the measurement inclination angles, the measurement inclination angles within the range of 0 to 45 degrees with respect to the normal direction of the substrate surface are divided for each pitch of 0.25 degrees. When the frequencies existing in the section are counted, the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness of the lower layer and the composite nitriding of Ti and Al having the cubic structure of the upper layer In either the product or the composite carbonitride layer, 0 to With the highest peak is present in the tilt angle sections of the range of 0 degrees, the sum of the frequencies present in the range of the 0 to 10 degrees, it indicates the percentage of more than 30% of the total power at the inclination angle frequency distribution.
(F) In the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness among the lower layers, the inclination angle of the normal of the {422} plane with respect to the normal direction of the substrate surface is 0 to 10 degrees. In the region of the upper layer corresponding to the maximum width of the crystal grains in the direction parallel to the substrate surface, the inclination angle of the normal of the {422} plane with respect to the normal direction of the substrate surface is in the range of 0 to 10 degrees. And a crystal grain of the Ti and Al composite nitride or composite carbonitride layer having the cubic crystal structure, and the crystal grain is normal to the {422} plane with respect to the normal direction of the substrate surface The Ti and Al composite nitride or composite carbonitride layer having a cubic structure having an inclination angle of 0 to 10 degrees occupies an area ratio of 50% or more of the entire crystal grain area. A surface-coated cutting tool.   The surface-coated cutting tool according to claim 1, wherein the Ti compound layer having an average layer thickness of 50% or more of the total average layer thickness of the lower layer is a Ti carbonitride layer.   An uppermost surface layer including at least an aluminum oxide layer having an average layer thickness of 1 to 25 μm is further formed on the surface of the upper layer composed of the composite nitride or composite carbonitride layer of Ti and Al. The surface-coated cutting tool according to claim 1 or 2.