JP6650108B2 - Surface coated cutting tool with excellent chipping and wear resistance - Google Patents

Description

  The present invention provides an excellent hard coating layer even when cutting various kinds of steel or cast iron at a high speed and under a high-speed intermittent heavy cutting condition in which a high load such as an intermittent or impact is applied to the cutting edge. The present invention relates to a surface-coated cutting tool (hereinafter, referred to as a coated tool) which exhibits excellent chipping resistance and wear resistance and exhibits excellent cutting performance over a long period of time.

2. Description of the Related Art Conventionally, generally, a substrate (hereinafter, these are collectively referred to as a tool substrate) formed of a tungsten carbide (hereinafter, referred to as WC) -based cemented carbide or a titanium cermet (hereinafter, referred to as TiCN) -based cermet is generally provided on a surface of the substrate. ,
(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, and a carbonate (hereinafter, referred to as TiCO). ) Layer, and a Ti compound layer comprising one or more of a carbon oxynitride (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 coating tool obtained by vapor-depositing a hard coating layer composed of the above (a) and (b).

However, the above-mentioned conventional coated tool exhibits excellent wear resistance in continuous cutting or interrupted cutting of various types of steel or cast iron, for example. There is a problem that peeling and chipping easily occur and the tool life is shortened.
Therefore, various kinds of coating tools in which the upper layer is improved in order to suppress peeling and chipping of the hard coating layer have been proposed.

For example, in Patent Document 1, a non-oxide film made of at least one of carbides, nitrides, and carbonitrides of metals belonging to Groups 4a, 5a, and 6a of the periodic table is formed on the surface of a tool base. 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 an oxide-based single-layer coating or a multilayer coating of nitride and oxycarbonitride, and has a non-oxide film and a bonding phase in an epitaxial relationship; By doing so, a coated tool has been proposed in which the adhesion strength between the tool base and the alumina coating is increased, and the fracture resistance, the peel resistance, and the wear resistance are improved.

In addition, for example, Patent Document 2 discloses that at least two layers having different chemical compositions selected from nitride, carbide, and carbonitride containing one or more metal elements are provided on the surface of a tool base. in the cutting tool having a laminated hard coating, the composition of the surface-side outermost layer _{(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 ), provided that 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 coating is 0.8 to 50 μm, and each of the layers substantially has a rock salt type crystal structure; and Since the crystal structure of each layer is substantially epitaxially grown at the interface, the wear resistance and adhesion of the hard coating are improved. It has been proposed that

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

  In recent years, the performance of cutting equipment has been remarkably improved. On the other hand, there is a strong demand for labor saving, energy saving, and lower cost for cutting, and with this, cutting has been further accelerated, and high cutting, high feed, etc. In cutting heavy cutting, etc., the cutting edge tends to receive a high impact and intermittent load.However, in the case of the above-mentioned conventional coated tool, this is required for continuous cutting under normal conditions such as steel or cast iron. There is no problem when used for cutting or intermittent cutting, but especially when used under high-speed intermittent cutting conditions, the wear resistance of the hard coating layer is not sufficient, and the service life can be shortened in a relatively short time is the current situation.

In view of the above, the present inventors have developed a Ti compound crystal grain constituting the lower layer formed on the surface of the tool base and a composite nitride of Ti and Al constituting the upper layer formed thereon. In addition, in order to control the epitaxial relationship between the composite carbonitride (hereinafter sometimes abbreviated as TiAlCN) and the crystal grains thereof, intensive research has been made to improve the chipping resistance and wear resistance of the entire hard coating layer. Was piled up.
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 NaCl-type face-centered cubic (hereinafter sometimes simply referred to as “cubic”) crystal structure. Regarding the crystal grains of the compound layer (preferably, a layer of Ti carbonitride (hereinafter sometimes referred to as “TiCN” in some cases)) and the crystal grains of the TiAlCN layer constituting the upper layer, ｛422 of each crystal grain When the frequency distribution of the inclination angle formed by the normal of｝ and the normal direction of the surface of the substrate is measured, the peak of the frequency is present in the inclination angle section of 0 to 10 degrees with respect to the normal direction, Is 30% or more of the whole frequency,
(2) 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 grain having an inclination angle of 0 to 10 degrees between the normal direction of the substrate surface and the normal of {422}, {422} There are TiAlCN crystal grains having an inclination angle of 0 to 10 degrees with respect to the normal direction of the substrate surface, and this crystal grain is different from the normal direction of the substrate surface by {422}. When the inclination angle is 50% or more of the TiAlCN crystal grains 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} Shape of crystal grains with a tilt angle of 0 to 10 degrees formed by the normal of By increasing the ratio, the hardness and the adhesion strength between the lower layer and the upper layer are improved, and even at high speed, high-speed intermittent cutting conditions where intermittent and impactful high loads act on the cutting edge It has been found that the layer has excellent adhesion strength and exhibits excellent chipping resistance and abrasion resistance.

The present invention has been made based on the above findings,
"(1) A hard coating comprising a lower layer and an upper layer on the surface of a tool substrate made of either a tungsten carbide-based cemented carbide, a titanium carbonitride-based cermet, or a cubic boron nitride-based ultrahigh-pressure sintered body. In a surface-coated cutting tool having a layer formed thereon,
(A) The lower layer has a total average layer thickness of 1 to 20 μm including one or more of a Ti carbide layer, a nitride layer, a carbonitride layer, a carbonate layer, and a carbonitride layer. And one of the layers 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 carbonitride layer of Ti and Al having an average layer thickness of 1 to 20 μm;
(C) forming a composite nitride or composite carbonitride layer of Ti and Al,
Composition formula: (Ti _1-x Al _x ) ( _{CyN 1-y} )
In this case, the average content ratio X _{ave of} Al in the total amount of Ti and Al and the average content ratio Y _ave of C in the total amount of C and N (where X _ave and Y _ave are atomic ratios) Satisfy 0.60 ≦ X _ave ≦ 0.95 and 0 ≦ Y _ave ≦ 0.005, respectively.
(D) In the lower layer, 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 NaCl-type face-centered cubic crystal structure, and the Ti of the upper layer has The crystal grains of the composite nitride or composite carbonitride layer of Al and Al have a crystal structure composed of a NaCl-type face-centered cubic structure single phase or a mixed phase of a NaCl-type face-centered cubic structure and a hexagonal structure,
(E) 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 a composite nitride or composite carbonitride of Ti and Al having the cubic structure of the upper layer When the crystal orientation of each crystal grain of the object layer is analyzed from the longitudinal section direction using an electron beam backscatter diffraction device, the method of {422} plane, which is the crystal plane of the crystal grain with respect to the normal direction of the substrate surface, is used. The inclination angles formed by the lines are measured, and among the measurement inclination angles, the measurement inclination angles that are within the range of 0 to 45 degrees with respect to the normal direction of the substrate surface are divided at intervals of 0.25 degrees. When the frequencies present in the sections are totaled, a composite nitride of Ti and Al having the cubic structure of 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 cubic structure of the upper layer is obtained. In the composite or composite carbonitride layer, 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 of the lower layer, the inclination angle of the normal line of the {422} plane with respect to the normal direction of the substrate surface is 0 to 10 degrees. Through the interface between the lower layer and the upper layer corresponding to the maximum width of the crystal grains in the direction parallel to the surface of the substrate within the range, the inclination angle of the normal line of the {422} plane with respect to the normal direction of the substrate surface is Crystal grains of the composite nitride or carbonitride layer of Ti and Al having the cubic structure within the range of 0 to 10 degrees are adjacent to each other , and the crystal grains are normal to the surface of the substrate. 50% of the total area of the crystal grains of the Ti and Al composite nitride or composite carbonitride layer having the cubic structure in which the inclination angle of the normal line of the {422} plane with respect to the direction is in the range of 0 to 10 degrees. A surface coated cutting tool occupying the above area ratio.
(2) The surface-coated cutting tool according to (1), wherein the Ti compound layer having an average thickness of 50% or more of the total average 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 made of the composite nitride or carbonitride layer of Ti and Al. The surface-coated cutting tool according to the above (1) or (2), wherein "
It is characterized by the following.

  Hereinafter, the constituent layers of the hard coating layer of the coated tool of the present invention will be described in detail.

FIG. 1 shows a schematic diagram of the layer structure of the hard coating layer of the present invention. In FIG. 1, a 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 morphology is observed at the interface between the upper layer and the lower layer, as if crystal grains were growing through the interface.
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):
A Ti compound layer (for example, a Ti carbide (TiC) layer, a nitride (TiN) layer, a carbonitride (TiCN) layer, a carbon oxide (TiCO) layer, and a carbonitride oxide (TiCNO) layer) is basically Is present as a lower layer of the TiAlCN layer. The excellent high-temperature strength of the hard coating layer allows the hard coating layer to have a high-temperature strength, and adheres to both the tool base and the TiAlCN layer of the upper layer. Has an effect of maintaining the adhesion to the tool base. However, if the total average layer thickness is less than 1 μm, the above effect cannot be sufficiently exerted. On the other hand, if the total average layer thickness exceeds 20 μm, thermoplastic deformation occurs particularly in high-speed interrupted cutting with high heat generation. The total average layer thickness was determined to be 1 to 20 μm, since it easily occurs and causes uneven wear.
Furthermore, in order to take over the {422} orientation of the lower layer and epitaxially grow the upper layer and improve the adhesion strength of the hard coating layer, the lower layer has at least a cubic structure, and has an average layer thickness of 1 μm or more. And a Ti compound layer (for example, a Ti carbide layer, a nitride layer, a carbonitride layer, and a carbonitride layer) having an average thickness of 50% or more of the total average thickness of the lower layer. )) Must have a {422} orientation. When the average thickness of the Ti compound layer having the {422} orientation is less than 1 μm or less than 50% of the total average 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 chipping resistance and the adhesion strength of the upper layer cannot be improved.

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 composed of TiCN crystal grains.
For example, the lower TiCN layer having the {422} orientation can be formed using a general 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%, remainder _H 2,
Reaction atmosphere temperature: 750-800 ° C.
Reaction atmosphere pressure: 5 to 10 kPa,
Under the conditions described above, by chemical vapor deposition until the target average layer thickness is reached.

Upper layer (TiAlCN layer having a cubic single-phase structure or a mixed-phase crystal structure of a cubic structure and a hexagonal structure):
The upper layer of the hard coating layer of the present invention comprises a chemical vapor deposited TiAlCN layer having a cubic single-phase structure having an average layer thickness of 1 to 20 μm or a mixed crystal structure of a cubic structure and a hexagonal structure.
Since the TiAlCN layer constituting the upper layer of the present invention has {422} orientation, it has high hardness and exhibits excellent wear resistance. However, when the average layer thickness is less than 1 μm, the layer thickness is small. When the wear resistance over a long period of use cannot be sufficiently ensured, on the other hand, when the average layer thickness exceeds 20 μm, the crystal grains become coarse and chipping easily occurs.
Therefore, the average layer thickness of the TiAlCN layer constituting the upper layer was determined to be 1 to 20 μm.
The upper layer may be a TiAlCN layer having a mixed phase of a cubic structure and a hexagonal structure as well as a single layer having a cubic structure.

When the TiAlCN layer constituting the upper layer of the present invention is represented by a composition formula: (Ti _1-x Al _x ) (N _1-y C _y ), the average content ratio X of Al to the total amount of Ti and Al _The content ratios Y _ave (where X _ave and Y _ave are both atomic ratios) of the total amount of C and N of _ave and C are 0.60 ≦ X _ave ≦ 0.95 and 0 ≦ Y _ave ≦ Satisfies 0.005.
If 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. , The abrasion resistance is not sufficient. On the other hand, when the average content ratio X _{ave of} Al exceeds 0.95, the content ratio of Ti relatively decreases, thereby causing embrittlement and deteriorating chipping resistance.
Therefore, the average Al content X _ave (atomic ratio) is set to 0.60 ≦ X _ave ≦ 0.95.
When the average content ratio (atomic ratio) Y _ave of the C component contained in the composite nitride or carbonitride layer is a trace amount in the range of 0 ≦ Y _ave ≦ 0.005, the upper layer and the lower layer The impact of cutting is alleviated by improving the adhesion of the steel and the lubricity, and as a result, the fracture resistance and chipping resistance of the composite nitride or composite carbonitride layer are improved. On the other hand, when the content ratio Y _ave of the C component deviates from the range of 0 ≦ Y _ave ≦ 0.005, the toughness of the composite nitride or carbonitride layer is reduced, so that the chipping resistance and chipping resistance are reduced. I do.
Therefore, the content ratio Y _ave (atomic ratio) of the C component is set to 0 ≦ Y _ave ≦ 0.005.

Number distribution of angle of inclination of {422} plane of crystal grains of lower layer and upper layer:
Electron beam back scattering of 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 to the {422} plane, which is the crystal plane of the crystal grain, with respect to the normal to the tool base surface (the direction perpendicular to the tool base surface in the polished cross section). Is measured, and among the inclination angles, the inclination angles within a range of 0 to 45 degrees with respect to the normal direction are divided at intervals of 0.25 degrees, and the frequencies existing in each division When the total of the frequencies in the inclination angle distribution within the range of 0 to 10 degrees has the highest peak, and the total of the frequencies existing in the range of 0 to 10 degrees is 30% of the total frequencies in the inclination angle number distribution, Number of tilt angle distribution forms with above ratio It is necessary to show.
Here, in either the lower layer or the upper layer, if the inclination angle number distribution for the {422} plane is out of the above range, the {422} plane orientation of the entire hard coating layer is reduced, and the hardness is reduced. The wear resistance is impaired by the decrease.
Furthermore, in order to promote the epitaxial growth of the lower layer and the upper layer in addition to the {422} plane orientation 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 is required. in a lower layer and an upper layer inclination angle of the normal of the {422} plane with respect to the normal direction of the substrate surface corresponding to the maximum width in a direction parallel to the grain of the substrate surface is in the range of 0 degrees the interface through the inclination angle of the normal of the {422} plane with respect to the normal direction of the substrate surface is present adjacent crystal grains of TiAlCN layer having a cubic crystal structure is in the range of 0 degrees And, the TiAlCN crystal grains have a tilt angle of the normal line of the {422} plane with respect to the normal direction of the substrate surface within the range of 0 to 10 degrees. 50% or more of the area Mel that there is a need.
That is, if the area ratio of the TiAlCN crystal grains epitaxially growing 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 easily occurs in high-speed interrupted cutting or the like.
By promoting the {422} plane orientation of the lower layer and the {422} plane orientation of the upper layer defined by the present invention, and further promoting the epitaxial growth of crystal grains having 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 hard coating layer as a whole is improved.
As a result, such a coated tool suppresses the occurrence of chipping, peeling, and the like even when subjected to, for example, high-speed interrupted cutting of an alloy steel, and exhibits excellent wear resistance.
2 and 3 show examples of the distribution of the number of inclination angles obtained for the lower layer and the upper layer of the present invention. FIG. 2 shows the 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 a cubic TiCN crystal grain having an upper layer, and FIG. 3 is a graph obtained for a cubic TiAlCN crystal grain of an upper layer.

Top layer:
The present invention relates to an oxidation method having an average layer thickness of 1 to 25 μm on the surface of an upper layer composed of a cubic single phase having an average layer thickness of 1 to 20 μm or a TiAlCN layer having a cubic and hexagonal mixed phase crystal structure. The outermost surface layer including at least the aluminum layer can be further coated.
The aluminum oxide layer as the outermost layer increases the high-temperature hardness and heat resistance of the hard coating layer, but if the average layer thickness of the outermost layer is less than 1 μm, the hard coating layer cannot have the above characteristics sufficiently. 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 edge tend to cause thermoplastic deformation, which causes uneven wear, and accelerate the wear. Therefore, the average layer thickness is desirably 1 to 25 μm.

Film formation method:
The lower layer and the outermost surface layer of the present invention can be formed by, for example, an ordinary chemical vapor deposition method and apparatus.
For example, when a TiC layer, a TiN layer, a TiCN layer, or the like is formed 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, usually, Using the chemical vapor deposition equipment of
Reaction gas composition (% by volume): TiCl ₄ 2 to 2.5%, N ₂ 5 to 10%, CO 0 to 2%, CH ₃ CN 0.4 to 0.6%, balance H ₂ ,
Reaction atmosphere temperature: 750-800 ° C.
Reaction atmosphere pressure: 5 to 10 kPa,
By performing chemical vapor deposition until the target average layer thickness is obtained under the conditions described above, a TiC layer, a TiN layer, a TiCN layer, and the like having a {422} plane orientation can be formed.
Also, the upper layer can be formed by a normal chemical vapor deposition method. For example, the upper layer can be formed by 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 were supplied to a chemical vapor deposition reactor equipped with a tool base. , Each of which is supplied from a separate gas supply pipe into the reaction apparatus, the composition of the reaction gas 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: 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 a 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 has a normal to the {422} plane of the crystal grains of the Ti compound layer having a cubic structure and the substrate surface. The tilt angle number distribution with respect to the normal direction is 0% to 10 °, the tilt angle number distribution is 30% or more, and the {422} plane of TiAlCN crystal grains having a cubic crystal structure in the upper layer is also provided. The inclination angle number distribution in which the inclination angle between the normal line of the substrate and the normal direction of the surface of the substrate is in the range of 0 to 10 degrees is 30% or more, and the average of the total average layer thickness of the lower layer is 50% or more. The inclination ratio between the area ratio of the {422} plane of the crystal grains of the Ti compound layer having the layer thickness and the cubic structure and the TiAlCN crystal grains of the epitaxially grown upper layer to the normal direction of the substrate surface is 0. At more than 50% of the whole TiAlCN grains which is -10 degrees As a result, the hardness of the lower layer and the upper layer is improved, and the bonding strength between the lower layer and the upper layer is improved. As a result, a high-speed, intermittent and impactful high load acts on the cutting edge. Even under high-speed intermittent cutting conditions, the hard coating layer exhibits excellent chipping resistance and exhibits excellent wear resistance over a long period of use.

FIG. 1 shows a schematic diagram of a layer structure of a hard coating layer of the present invention. FIG. 3 shows an example of a graph obtained for a cubic structure TiCN crystal grain having an average layer thickness of 50% or more of the total average layer thickness of the lower layer in the inclination angle number distribution obtained for the lower layer and the upper layer of the present invention. . FIG. 5 shows an example of a graph obtained for TiAlCN crystal grains having a cubic structure of the upper layer in the distribution of the number of inclination angles obtained for the lower layer and the upper layer of the present invention.

  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 each having an average particle diameter of 1 to 3 μm were prepared, and these raw material powders were mixed as shown in Table 1. After mixing with the composition, wax was added, and the mixture was ball-milled in acetone for 24 hours, dried under reduced pressure, and then pressed into a green compact having a predetermined shape at a pressure of 98 MPa. Vacuum sintering at a predetermined temperature in the range of １４1470 ° C. for 1 hour, and after sintering, manufacture WC-based cemented carbide tool bases A to C having insert shapes of ISO standard SEEN1203AFSN, respectively. did.

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

Next, using a chemical vapor deposition apparatus on the surface of these tool bases A to D,
First, under the formation conditions shown in Table 3, the lower layer shown in Table 7 was formed.
Next, the formation conditions A to J shown in Tables 5 and 6, that is, from the gas group A consisting of NH ₃ and H ₂ , and TiCl ₄ , AlCl ₃ , NH ₃ , N ₂ , C ₂ H ₄ , and H ₂ The reaction gas composition (volume% based on the total of the gas group A and the gas group B) as the gas group B and the method of supplying each gas is NH ₃ : 1.5 to 3.0% as the gas group A. , H ₂ : 50 to 75%, as gas group B: 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 : residual, 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, a phase difference of 0.10 to 0.20 seconds between gas supply A and gas supply B, In the meantime, the coated tools 1 to 10 of the present invention were produced by performing a thermal CVD method to form an upper layer.
For the coated tools 8 to 10 of the present invention, the outermost surface layer shown in Table 7 was formed under the forming conditions shown in Table 3.

For the purpose of comparison, the lower layer shown in Table 8 was formed on the surface of the tool bases A to D under the forming conditions shown in Table 4 using a normal chemical vapor deposition apparatus. Under the conditions shown and the target layer thickness (μm) shown in Table 8, a hard coating layer including at least a composite nitride or carbonitride layer of Ti and Al was formed by vapor deposition in the same manner as the coated tools 1 to 10 of the present invention. .
For the comparative coated tools 8 to 10, the upper layers shown in Table 8 were formed under the forming conditions shown in Table 4 in the same manner as the coated tools 8 to 10 of the present invention.

  The cross section of each of the constituent layers of the coated tools 1 to 10 of the present invention and the comparative coated tools 1 to 10 in the direction perpendicular to the tool base was measured using a scanning electron microscope (magnification 5000 times), and 5 points in the observation visual field were measured. Were measured and averaged to obtain an 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.

For the average Al content X _ave of the TiAlCN layer of the upper layer, the electron beam was irradiated from the sample surface side in a sample whose surface was polished using an electron-beam probe-micro-analyzer (EPMA). Irradiation was performed, and the average content ratio _Xave of Al was determined from the average of 10 points of the analysis results of the characteristic X-rays obtained.
In addition, the average C content Y _ave was determined by Secondary-Ion-Mass-Spectroscopy (SIMS). An ion beam was irradiated to a range of 70 μm × 70 μm from the sample surface side, and the concentration emitted in the depth direction was measured for components emitted by the sputtering action. The average C content Y _ave indicates the average value of the TiAlCN layer in the depth direction. However, the C content ratio excludes the unavoidable C content ratio that is included even if a gas containing C is not intentionally used 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 set to 0 is determined as the inevitable C content ratio, and C ₂ H ₄ is intentionally determined. The value obtained by subtracting the unavoidable C content from the content (atomic ratio) of the C component contained in the TiAlCN layer obtained when the material was supplied was determined as Y _ave .

Regarding the distribution of the number of inclination angles of the hard coating layer, first, the field emission was performed with the cross section of the Ti compound layer of the lower layer having an average layer thickness of 50% or more of the total average layer thickness used as the polished surface. Is set in the column of a scanning electron microscope, and an electron beam with an acceleration voltage of 10 kV and an irradiation current of 1 nA at an incident angle of 70 ° is 1 μm in a direction perpendicular to the surface of the tool base. In the horizontal direction, each crystal grain having a cubic crystal structure existing in the measurement range is irradiated at an interval of 0.1 μm / step over a range of 50 μm, and the tool is irradiated with a tool using an electron beam backscatter diffraction imager. An inclination angle formed by a normal to a {422} plane, which is a crystal plane of the crystal grain, with respect to a normal to the base surface (a direction perpendicular to the tool base surface in the cross-section polished surface) is measured, and based on the measurement result, And the measured inclination angle , The measured tilt angle in the range of 0 to 45 degrees is divided for each pitch of 0.25 degrees, and the frequencies present in each section are totaled to determine the tilt angle section where the highest peak exists. , And the ratio of frequencies existing in the range of 0 to 10 degrees was determined.
Tables 7 and 8 show the results.

Next, the distribution of the number of inclination angles of the upper layer of the hard coating layer was also set in a column 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 having an acceleration voltage of 1 nA was applied at an irradiation current of 0.5 μm in a direction perpendicular to the surface of the tool base, and an interval of 0.1 μm / step in a range of 100 μm in a direction horizontal to the surface of the tool base. Then, the individual grains having a cubic crystal structure existing in the measurement range are irradiated, and the normal line of the tool base surface (the direction perpendicular to the tool base surface in the cross-section polished surface) is irradiated using an electron backscatter diffraction imager. The inclination angle formed by the normal to the {422} plane, which is the crystal plane of the crystal grain, is measured, and based on the measurement result, the inclination angle is in the range of 0 to 45 degrees. Measurement inclination angle every 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.

Further, the crystal grains of the Ti compound layer having an average thickness of 50% or more of the total average thickness of the lower layer of the hard coating layer and the TiAlCN crystal grains of the upper layer are individually crystallized 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 the average layer thickness of 50% or more of the total average layer thickness of the lower layer Through the interface between the lower layer and the upper layer corresponding to the maximum width of the crystal grains in the direction parallel to the substrate surface in the Ti compound layer having a thickness, the normal of the {422} plane to the normal direction of the substrate surface Crystal grains of the Ti and Al composite nitride or composite carbonitride layer having a cubic structure having an inclination angle in the range of 0 to 10 degrees are present adjacent to each other , and the crystal grains are formed on the surface of the substrate. Of the normal to the {422} plane with respect to the normal Occupies at least 50% of the total area of the crystal grains of the composite nitride or composite carbonitride layer of Ti and Al having the cubic structure in the range of 0 to 10 degrees. Is determined.
That is, for the coated tools 1 to 10 of the present invention and the comparative coated tools 1 to 10, the 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 is set to Range of 1.0 μm in the thickness direction of the upper layer, and a measurement range (2.0 μm or more × 50 μm) of a polished cross section of 50 μm in a direction parallel to the surface of the tool base. An electron beam with an acceleration voltage of 15 kV and an irradiation current of 1 nA at an incident angle of 70 ° is set on the polished surface within a measurement range of each of the polished surfaces by being set in a column of a field emission scanning electron microscope. Each of the grains having a cubic crystal lattice is irradiated, and a measurement area of 2.0 or more × 50 μm is measured at an interval of 0.1 μm / step with an electron backscattering diffraction imager at a normal of the surface of the tool base. On the other hand, in the crystal plane of the crystal grain, The inclination angle formed by the normal line of the {422} plane was 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 was measured. Ti and Al having the cubic structure in which the inclination angle of the normal line of the {422} plane with respect to the normal direction of the substrate surface is in the range of 0 to 10 degrees through the corresponding interface between the lower layer and the upper layer. The presence of adjacent crystal grains of the composite nitride or carbonitride layer confirms the epitaxial relationship defined in the present invention, and the crystal grains are at least 2.0 × 50 μm in the measurement region. Of the Ti and Al composite nitride or composite carbonitride layer having the cubic structure, in which the inclination angle of the normal line of the {422} plane with respect to the normal direction of the substrate surface in the region is in the range of 0 to 10 degrees. Occupies 50% or more of the total area of crystal grains Seeking whether, determines prescribed in the present invention.
In addition, 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 coated tools 1 to 10 of the present invention and the comparative coated tools 1 to 10 were clamped with a fixing jig at the tip of a tool steel cutter having a cutter diameter of 125 mm. As shown below, dry high-speed face milling, which is a type of high-speed interrupted cutting of alloy steel, and a center-cut cutting test were performed, and the flank wear width of the cutting edge was measured. Table 9 shows the results.

Tool base: Tungsten carbide based cemented carbide, titanium carbonitride based cermet,
Cutting test: Dry high-speed face milling, center cut cutting,
Work material: JIS SCM440 block material of width 100mm, length 400mm,
Rotation speed: 980 min ^-1 ,
Cutting speed: 385 m / min,
Notch: 1.5 mm,
Feed amount per blade: 0.15 mm / blade
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 each having an average particle size of 1 to 3 μm are prepared. Compounded in the composition shown in Table 10, further added wax, mixed in a ball mill in acetone for 24 hours, dried under reduced pressure, and then pressed into a green compact of a predetermined shape at a pressure of 98 MPa, and this green compact was pressed. Vacuum sintering is performed at a predetermined temperature in the range of 1370 to 1470 ° C. for 1 hour in a vacuum of 5 Pa, and after sintering, the cutting edge is subjected to a honing process of R: 0.07 mm to obtain an ISO standard. Tool bases E to G made of a WC-based cemented carbide having an insert shape of CNMG120412 were manufactured, respectively.

  In addition, 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 as raw material powders, These raw material powders were blended according to the blending composition shown in Table 11, wet-mixed in a ball mill for 24 hours, dried, and then pressed into a green compact at a pressure of 98 MPa, and the green compact was compressed to a nitrogen pressure of 1.3 kPa. Sintering is performed in an atmosphere at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge is subjected to a honing process of R: 0.09 mm to form a TiCN base having an insert shape of ISO standard CNMG120412. A tool base H made of cermet was formed.

Next, on the surfaces of the tool bases E to G and the tool base H, at least (Ti ₁₎ was obtained by using a chemical vapor deposition apparatus in the same manner as in Example 1 under the conditions shown in Tables 3, 5 and 6. _-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.
For the coated tools 18 to 20 of the present invention, upper layers as shown in Table 12 were formed under the forming conditions shown in Table 3.

For the purpose of comparison, the surface of the tool bases E to G and the tool base H were similarly subjected to the conditions shown in Tables 4, 5 and 6 and the target layer thicknesses shown in Table 13 by using a normal chemical vapor deposition apparatus. Then, comparative coated tools 11 to 20 shown in Table 13 were produced by vapor-depositing and forming a hard coating layer in the same manner as the coated tool of the present invention.
In addition, similarly to the coated tools 18 to 20 of the present invention, for the comparative coated tools 18 to 20, the upper layers shown in Table 13 were formed under the forming conditions shown in Table 4.

  The cross sections of the constituent layers of the coated tools 11 to 20 of the present invention and the comparative coated tools 11 to 20 were measured by using a scanning electron microscope (magnification: 5000 times), and the layer thicknesses at five points in the observation visual field were measured and averaged. When the average layer thickness was obtained by using the above method, the average layer thickness was substantially the same as the target layer thickness shown in Tables 12 and 13.

The average Al content X _ave and the average C content Y _ave of the TiAlCN layer of the upper layer were determined in the same manner as in Example 1 using an electron beam microanalyzer (Electron-Probe-Micro-Analyser: EPMA). .
The inclination angle and the inclination angle number distribution formed by the normal line 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 line of the tool base surface are described. It was determined in the same manner as in Example 1.
Further, the area ratio of the TiAlCN crystal grains of the upper layer epitaxially growing in the normal direction of the {422} plane of the crystal grains of the lower layer adjacent to each other via the interface was obtained in the same manner as in Example 1. Was.
Tables 12 and 13 show these values.

Next, with the coated tools 11 to 20 of the present invention and the comparative coated tools 11 to 20 in the state where each of the various coated tools is screwed to the tip of the tool steel tool with a fixing jig, the following will be described. A dry high-speed intermittent cutting test of carbon steel and a wet high-speed intermittent cutting test of cast iron were performed, and the flank wear width of the cutting edge was measured in each case.
Cutting condition 1:
Work material: JIS S45C lengthwise round bar with four equally spaced longitudinal grooves,
Cutting speed: 390 m / min,
Cut: 1.0 mm,
Feed: 0.1 mm / rev,
Cutting time: 5 minutes,
(Normal cutting speed is 220m / min),
Cutting condition 2:
Work material: JIS FCD700 Four rods with longitudinal grooves at equal intervals in the longitudinal direction,
Cutting speed: 325 m / min,
Notch: 1.5 mm,
Feed: 0.1 mm / rev,
Cutting time: 5 minutes,
(Normal cutting speed is 200m / min),
Table 14 shows the results of the cutting test.

As raw material powders, 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. The mixture was blended into the composition, wet-mixed in a ball mill for 80 hours, dried, and then press-molded at a pressure of 120 MPa into a compact having a diameter of 50 mm × thickness: 1.5 mm. Is sintered in a vacuum atmosphere at a pressure of 1 Pa at a predetermined temperature within a range of 900 to 1300 ° C. for 60 minutes to prepare a pre-sintered body for a cutting blade. This pre-sintered body is prepared separately. An ordinary ultra-high pressure sintering apparatus in a state of being superposed on a WC-based cemented carbide support piece having a size of 50 mm × thickness: 2 mm, having the following composition: Co: 8 mass%, WC: remaining composition And normal pressure, 4 Pa, temperature: at a predetermined temperature in the range of 1200 to 1400 ° C., ultra-high pressure sintering under the condition of holding time: 0.8 hour, and after sintering, the upper and lower surfaces are polished using a diamond grindstone. WC: 5% by mass, TaC: 5% by mass, WC: Remaining composition and shape of JIS standard CNGA120412 (thickness: 4.76 mm x inscribed circle diameter: 12.7 mm In the brazing portion (corner portion) of the insert body made of a WC-based cemented carbide having a rhombus shape, Zr: 37.5%, Cu: 25%, and Ti: After brazing using a brazing material of a Zr-Cu alloy and processing the outer periphery to a predetermined size, the cutting edge portion is subjected to a honing process with a width of 0.13 mm and an angle of 25 °, and further subjected to finish polishing to obtain an ISO. Standard CNGA12 Tool substrate b having a 412 insert shape, The filtrate was produced, respectively.

Next, the lower layers shown in Table 16 were formed on the surfaces of these tool bases A and B using a chemical vapor deposition apparatus under the forming conditions shown in Table 3 in the same manner as in Example 1. The coated tools 21 to 26 of the present invention were produced by performing a thermal CVD method for a predetermined time under the conditions shown in Table 6 to form an upper layer.
In addition, about the coated tools 25-26 of this invention, the upper layer shown in Table 16 was formed on the formation conditions shown in Table 3.

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

  In addition, the cross sections of the coated tools 21 to 26 of the present invention and the comparative coated tools 21 to 26 were measured using a scanning electron microscope, and the layer thickness at five points in the observation visual field was measured and averaged to obtain an average layer thickness. .

The average Al content X _ave and the average C content Y _ave of the TiAlCN layer of the upper layer were determined in the same manner as in Example 1 using an electron-beam microanalyzer (Electron-Probe-Micro-Analyser: EPMA). .
The inclination angle and the inclination angle number distribution formed by the normal line 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 line of the tool base surface are described. It was determined in the same manner as in Example 1.
Further, the area ratio of the TiAlCN crystal grains of the upper layer epitaxially growing in the normal direction of the {422} plane of the crystal grains of the lower layer adjacent to each other via the interface was obtained in the same manner as in Example 1. Was.
Tables 16 and 17 show these values.

Next, the coated tools 21 to 26 of the present invention and the comparative coated tools 21 to 26 will be described below in a state where each of the various coated tools is screwed to the tip of a tool steel tool with a fixing jig. Then, a dry high-speed intermittent cutting test of a carburized and quenched alloy steel was performed, and the flank wear width of the cutting edge was measured.
Work material: JIS SCr420 (hardness: HRC62), four longitudinally grooved round bars at regular intervals in the longitudinal direction,
Cutting speed: 255 m / min,
Cut: 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 1-26 of the present invention showed that the crystal grains exhibiting the {422} orientation of the lower layer and the {422} of the upper layer adjacent to each other via the interface. ＴｉEpitaxial growth of TiAlCN crystal grains showing orientation improves the adhesion density at the interface and increases the hardness of the hard coating layer, resulting in high heat generation and intermittent / impact impact on the cutting edge. Even when used in high-speed intermittent cutting conditions in which a high load acts, the hard coating layer has excellent chipping resistance and exhibits excellent wear resistance over a long period of use.
On the other hand, in the comparative coated tools 1-26, in high-speed intermittent cutting, the occurrence of abnormal damage such as chipping, chipping, peeling, etc. of the hard coating layer, and a decrease in wear resistance resulted in a relatively short service life. It is clear that

  The coated tool of the present invention is not limited to continuous cutting and intermittent cutting under normal conditions such as various steels and cast irons, and severe cutting conditions such as high-speed intermittent cutting in which a high load such as intermittent / impact load acts on the cutting edge. Even under the condition, excellent chipping resistance and abrasion resistance are exhibited, so that it can sufficiently respond to high performance of cutting equipment, labor saving and energy saving of cutting work, and further cost reduction. .

Claims (3)

A hard coating layer consisting of a lower layer and an upper layer is formed on the surface of a tool base made of either a tungsten carbide-based cemented carbide, a titanium carbonitride-based cermet, or a 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 including one or more of a Ti carbide layer, a nitride layer, a carbonitride layer, a carbonate layer, and a carbonitride layer. And one of the layers 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 carbonitride layer of Ti and Al having an average layer thickness of 1 to 20 μm;
(C) forming a composite nitride or composite carbonitride layer of Ti and Al,
Composition formula: (Ti _1-x Al _x ) ( _{CyN 1-y} )
In this case, the average content ratio X _{ave of} Al in the total amount of Ti and Al and the average content ratio Y _ave of C in the total amount of C and N (where X _ave and Y _ave are atomic ratios) Satisfy 0.60 ≦ X _ave ≦ 0.95 and 0 ≦ Y _ave ≦ 0.005, respectively.
(D) In the lower layer, 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 NaCl-type face-centered cubic crystal structure, and the Ti of the upper layer has The crystal grains of the composite nitride or composite carbonitride layer of Al and Al have a crystal structure composed of a NaCl-type face-centered cubic structure single phase or a mixed phase of a NaCl-type face-centered cubic structure and a hexagonal structure,
(E) 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 a composite nitride or composite carbonitride of Ti and Al having the cubic structure of the upper layer When the crystal orientation of each crystal grain of the object layer is analyzed from the longitudinal section direction using an electron beam backscatter diffraction device, the method of {422} plane, which is the crystal plane of the crystal grain with respect to the normal direction of the substrate surface, is used. The inclination angles formed by the lines are measured, and among the measurement inclination angles, the measurement inclination angles that are within the range of 0 to 45 degrees with respect to the normal direction of the substrate surface are divided at intervals of 0.25 degrees. When the frequencies present in the sections are totaled, a composite nitride of Ti and Al having the cubic structure of 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 cubic structure of the upper layer is obtained. In the composite or composite carbonitride layer, 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 of the lower layer, the inclination angle of the normal line of the {422} plane with respect to the normal direction of the substrate surface is 0 to 10 degrees. Through the interface between the lower layer and the upper layer corresponding to the maximum width of the crystal grains in the direction parallel to the surface of the substrate within the range, the inclination angle of the normal line of the {422} plane with respect to the normal direction of the substrate surface is Crystal grains of the composite nitride or carbonitride layer of Ti and Al having the cubic structure within the range of 0 to 10 degrees are adjacent to each other , and the crystal grains are normal to the surface of the substrate. 50% of the total area of the crystal grains of the Ti and Al composite nitride or composite carbonitride layer having the cubic structure in which the inclination angle of the normal line of the {422} plane with respect to the direction is in the range of 0 to 10 degrees. A surface coated cutting tool occupying the above area ratio.   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 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 made of the composite nitride or composite carbonitride layer of Ti and Al. The surface-coated cutting tool according to claim 1 or 2, wherein