JP2019177424A - Surface-coated cutting tool the hard coating layer of which exhibits excellent oxidation resistance and deposition resistance - Google Patents

Abstract

To provide a coated tool which exhibits excellent chipping resistance and wearing resistance even when used for cutting heat-resistant alloy or the like.SOLUTION: A coated tool is provided with a coating layer with an average layer thickness of 1-20 μm in the base material, where the layer contains crystal grains of NaCl type face-centered cubic structure by 0.60≤x≤0.95, 0≤y≤0.0050 when expressed in (TiAl)(CN), and where, in the inclination angle count distribution with those of inclination angles of normal lines of a {112} face which are in a range of 0-45 degrees with respect to a normal direction of the tool body surface divided into 0.25-degree pitches, and with the number of angles present in each division summed up, a maximum peak is present in a division within a range of 0-10 degrees to have a total number of angles within this range by 35% or more, an average particle width of the crystal grains by 0.1-2.0 μm, an average aspect ratio by 2-10, and a difference between an average of x maximal values and minimal values by 0.03-0.25 in an orientation where periodical composition changes are expressed by <001> of the grains.SELECTED DRAWING: Figure 1

Description

  In the high-speed intermittent cutting of a heat-resistant alloy that is accompanied by high heat generation and an impact load acts on the cutting edge, the hard coating layer has excellent oxidation resistance and welding resistance. The present invention relates to a surface-coated cutting tool (hereinafter, sometimes referred to as a coated tool) that exhibits excellent cutting performance throughout the use of the tool.

Conventionally, tungsten carbide (hereinafter referred to as WC) based cemented carbide, titanium carbonitride (hereinafter referred to as TiCN) based cermet, or cubic boron nitride (hereinafter referred to as cBN) based super high pressure sintered body. There is a coated tool in which a Ti—Al-based composite nitride layer is formed on a surface of a tool substrate (hereinafter collectively referred to as a tool substrate) by a vapor deposition method as a hard coating layer. It is known to exhibit wear.
However, the conventional coated tool with the Ti-Al composite nitride layer is relatively excellent in wear resistance, but it is prone to abnormal wear when used under high-speed intermittent cutting conditions. Various proposals for improving the coating layer have been made.

For example, in Patent Document 1, (a) (Ti _1-x Al _x ) (C _y N _1-y ) (0.60 ≦ x ≦ 0.95, 0 ≦ ₁ ) having an average layer thickness of 1 to 20 μm on a tool base. y ≦ 0.005), and (b) when the crystal orientation of the crystal grains having the NaCl-type face-centered cubic structure in the hard coating layer is analyzed from the longitudinal sectional direction, the tool substrate The inclination angle within the range of 0 to 45 degrees out of the inclination angles formed by the normal lines of the {100} planes of the crystal grains with respect to the normal direction of the surface is divided for each pitch of 0.25 degrees, In the tilt angle number distribution obtained by counting the frequencies existing in each section, the highest peak exists in the tilt angle section within the range of 0 to 10 degrees and also exists in the range of 0 to 10 degrees. The total power is 35% or more of the total power in the tilt angle distribution, and (c) in the normal direction In addition, there is a periodic composition change in the crystal grains, and the difference Δx between the average of the maximum value and the minimum value of x is 0.03 to 0.25, and the period is 3 to 100 nm. The tool is listed.

Further, for example, in Patent Document 2, (a) (Ti _1-x Al _x ) (C _y N _1-y ) (0.60 ≦ x ≦ 0.95) having an average layer thickness of 1 to 20 μm on a tool base, (0 ≦ y ≦ 0.005), and (b) when the crystal orientation of the crystal grains having the NaCl-type face-centered cubic structure in the hard coating layer is analyzed from the longitudinal sectional direction, Of the inclination angles formed by the normal of the {110} plane with respect to the normal direction of the tool base surface, the inclination angles within the range of 0 to 45 degrees are divided into 0.25 degree pitches and exist in each section. When calculating the inclination angle frequency distribution by counting the frequencies, the highest peak exists in the inclination angle section in the range of 0 to 10 degrees, and the total of the frequencies existing in the range of 0 to 10 degrees is the inclination. 35% or more of the entire frequency in the angular frequency distribution, and the average grain width W of the crystal grains is 0.1 to (C) A periodic composition change exists in the crystal grains along the normal direction of the tool base surface, Is 4 to 150 nm, and a coated tool is described in which the difference Δx between the average of the maximum value and the average of the minimum value of x is 0.03 to 0.25.

Further, for example, in Patent Document 3, (a) (Ti _1-x Al _x ) (C _y N _1-y ) (0.60 ≦ x ≦ 0.95) having an average layer thickness of 1 to 20 μm on the tool base is disclosed. (0 ≦ y ≦ 0.005), and (b) when the crystal orientation of the crystal grains having the NaCl-type face-centered cubic structure in the hard coating layer is analyzed from the longitudinal sectional direction, An inclination angle formed by a normal line of the {111} plane of the crystal grain with respect to a normal direction of the tool base surface is measured, and an inclination angle within a range of 0 to 45 degrees with respect to the normal direction is included in the inclination angle. When the slope angle distribution within a range of 0 to 10 degrees exists when the slope angle distribution is obtained by summing up the frequencies existing in each section by dividing each pitch of 0.25 degrees, the above-mentioned peak is present, The sum of the frequencies existing within the range of 0 to 10 degrees is 45% of the total frequencies in the tilt angle frequency distribution. (C) having a columnar structure with an average particle width W of 0.1 to 2.0 μm and an average aspect ratio A of 2 to 10;
(D) A periodic composition change exists along one of the equivalent crystal orientations represented by <001> of the crystal grains, and the difference between the average of the maximum value and the average of the minimum values of the x A coated tool is described in which Δx is 0.03 to 0.25.

In addition, for example, Patent Document 4 discloses that a wear protection coating having a thickness of 3 to 25 μm has a chemistry of 0.70 ≦ x <1, 0 ≦ y <0.25, and 0.75 ≦ z <1.15. It has a stoichiometric coefficient, at least one of _{Ti 1-x Al x C y} N z layer thickness in the range of 1.5～17Myuemu, the _{Ti 1-x Al x C y} N z layer is 150nm Ti _1-x Al _x C _y N _z having a layered structure including a plurality of layers having the following thicknesses, wherein the plurality of layers have the same crystal structure and alternately different stoichiometric ratios of Ti and Al A coated tool is described that is formed in periodically alternating regions of the layer, wherein the Ti _1-x Al _x C _y N _z layer has a face-centered cubic crystal structure of 90 vol% or more.

JP, 2015-193071, A JP 2006-30319 A Japanese Patent Laid-Open No. 2006-64485 Special table 2017-508632 gazette

In recent years, there has been a strong demand for labor saving and energy saving in cutting, and along with this, cutting tends to further increase in speed and efficiency. Further, the coated tool is required to further improve abnormal damage resistance such as chipping resistance, chipping resistance, and peel resistance, and to have excellent wear resistance over a long period of use.
The coated tools described in Patent Documents 1 to 4 have excellent chipping resistance and wear resistance when subjected to high-speed intermittent cutting such as alloy steel, but have low thermal conductivity and high high-temperature strength. When cutting a heat-resistant alloy, which is a material that easily causes work hardening and is a highly difficult-to-cut material, there is a case where a sufficient tool life is not given.
Therefore, the technical problem to be solved by the present invention, that is, the object of the present invention is to provide excellent resistance to long-term use even when used for cutting highly difficult-to-cut materials such as heat-resistant alloys where the cutting edge becomes high in temperature. An object of the present invention is to provide a coated tool that exhibits chipping and wear resistance.

The present inventors present a composite nitride or composite carbonitride of Ti and Al (hereinafter sometimes referred to as “TiAlCN” or “(Ti _1-x Al _x ) (C _y N _1-y )”). As a result of intensive studies to improve the chipping resistance and wear resistance of the coated tool including the hard coating layer including the following, the following knowledge was obtained.
That is, when the orientation of the {112} plane is increased as the plane orientation of the TiAlCN layer constituting the hard coating layer, the resistance to wear, the toughness, and the wear resistance against high heat generated during cutting are improved in a balanced manner. We have discovered the surprising fact that wear resistance and fracture resistance are improved even when used in high-speed intermittent cutting of heat-resistant alloys.

The present invention has been made based on the above findings,
“(1) A surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool base made of any of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh-pressure sintered body In
(A) The hard coating layer includes at least a composite nitride layer or composite carbonitride layer of Ti and Al having an average layer thickness of 1.0 to 20.0 μm, and the composite nitride layer or the composite carbonitride layer Is represented by the composition formula: (Ti _1-x Al _x ) (C _y N _1-y ), it occupies the total amount of Ti and Al in the composite nitride layer or the composite carbonitride layer. The average content ratio x _avg , and the average content ratio y _avg (where x _avg and y _avg are atomic ratios) in the total amount of C and N in C of the composite nitride layer or the composite carbonitride layer are Satisfying 0.60 ≦ x _avg ≦ 0.95 and 0 ≦ y _avg ≦ 0.0050, respectively.
(B) The composite nitride layer or the composite carbonitride layer includes at least crystal grains of a composite nitride or composite carbonitride having a NaCl-type face-centered cubic structure,
(C) With respect to the composite nitride layer or the composite carbonitride layer, an electron beam backscattering diffractometer is used to change the crystal orientation of the crystal grains in the longitudinal section direction of the composite nitride layer or the composite carbonitride layer. The inclination angle formed by the normal of the {112} plane, which is the crystal plane of the crystal grain, is measured with respect to the normal direction of the surface of the tool base, and the surface of the tool base out of the inclination angles In the inclination angle number distribution obtained by dividing the inclination angle within the range of 0 to 45 degrees with respect to the normal direction of each for each pitch of 0.25 degrees and totaling the frequencies existing in each division The highest peak exists 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 35% or more of the entire degrees in the inclination angle frequency distribution. ,
(D) When the composite nitride layer or the composite carbonitride layer is observed from the longitudinal sectional direction, the average grain width W of the crystal grains is 0.1 to 2.0 μm, and the average aspect ratio A is 2.0 to It has a columnar structure of 10.0, and a periodic composition change of Ti and Al in the crystal grain exists along one of the equivalent crystal orientations represented by <001> of the crystal grain And the difference of the average of the maximum of the said content rate of Al and the average of minimum is 0.03-0.25, The surface coating tool characterized by the above-mentioned.
(2) The periodic composition change of Ti and Al in the crystal grain exists along one of the equivalent crystal orientations represented by <001> of the crystal grain, and the period in the orientation is 3 to 100 nm. The surface-coated tool according to (1), wherein the amount of change in the content ratio of Al is 0.01 or less in a plane perpendicular to the orientation.
(3) The lattice constant a of the crystal grains is 0.05a _TiN + 0.95a _AlN ≦ a ≦ 0.40a _TiN + 0. With respect to the lattice constant a _TiN of cubic _TiN and the lattice constant a _AlN of cubic AlN. 60a _AlN is satisfy | _filled , The surface coating tool as described in said (1) or (2) characterized by the above-mentioned.
(4) The composite nitride layer or the composite carbonitride layer is composed only of Ti and Al composite nitrides or crystal grains of the composite carbonitride having a NaCl-type face-centered cubic structure. The surface-coated tool according to any one of (1) to (3).
(5) Between the tool base and the hard coating layer, a Ti carbide layer, a nitride layer, a carbonate layer, and a carbon dioxide layer, or one or more Ti compound layers, The surface-coated tool according to any one of (1) to (4), wherein a lower layer having a total average layer thickness of 0.1 to 20.0 μm is present.

  The coated tool of the present invention improves the orientation of the {112} plane, thereby exhibiting a good balance between wear resistance and toughness and wear resistance against high heat generated during cutting, and cutting a heat-resistant alloy that is a highly difficult-to-cut material. Even if it is used, it has an excellent effect of improving wear resistance and fracture resistance.

It is a film | membrane structure schematic diagram which represented typically the cross section of the hard coating layer of this invention coated tool, and a dimension does not follow the magnitude | size of an actual structure | tissue. Measured for the TiAlCN layer constituting the hard coating layer of the coated tool of the present invention, the NaCl type face-centered cubic structure grains measured with respect to the normal of the tool base surface (in the direction perpendicular to the tool base surface on the cross-section polished surface) It is the graph shown about this invention coated tool 5 mentioned later as an example of inclination angle number distribution which the normal line of {112} surface makes. Regarding the TiAlCN layer constituting the hard coating layer of the coated tool of the present invention, in the crystal grains having a NaCl-type face-centered cubic structure in which a periodic composition change of Ti and Al exists, the composition change is less than that of the crystal grains. FIG. 6 is a diagram schematically showing that a composition change in a plane that exists along one of the equivalent crystal orientations represented by 001> and is orthogonal to the orientation is small.

  Next, the hard coating layer of the coated tool of the present invention will be described in more detail.

1. Average layer thickness of the composite nitride layer or composite carbonitride layer (TiAlCN layer) constituting the hard coating layer:
The hard coating layer included in the surface-coated cutting tool of the present invention is a composite nitride layer or composite carbonitride of Ti and Al represented by the composition formula: (Ti _1-x Al _x ) (C _y N _1-y ). Including at least a layer. This composite nitride layer or composite carbonitride layer has high hardness and excellent wear resistance, but the effect is particularly remarkable when the average layer thickness is 1.0 to 20.0 μm. . The reason is that if the average layer thickness is less than 1.0 μm, the average layer thickness is so thin that the wear resistance cannot be sufficiently secured over a long period of use, while the average layer thickness exceeds 20.0 μm, This is because the crystal grains of the composite nitride layer or composite carbonitride layer of Ti and Al are likely to be coarsened and chipping is likely to occur.

2. Composition of the TiAlCN layer constituting the hard coating layer:
The TiAlCN layer constituting the hard coating layer of the surface-coated cutting tool of the present invention has an average content ratio x _avg in the total amount of Ti and Al in Al and an average content ratio y _avg in the total amount of C and N in C (However, x _avg and y _avg are both atomic ratios) are controlled so as to satisfy 0.60 ≦ x _avg ≦ 0.95 and 0 ≦ y _avg ≦ 0.0050, respectively.
The reason for this is that if the average Al content x _avg is less than 0.60, the TiAlAl TiAlCN layer is inferior in hardness, so when it is subjected to high-speed intermittent cutting of a heat-resistant alloy or the like, it has wear resistance. On the other hand, if the average Al content ratio x _avg exceeds 0.95, the Ti content ratio is relatively reduced, leading to embrittlement and lowering of chipping resistance. Further, when the average content ratio y _avg of C is a very small amount in the range of 0 ≦ y _avg ≦ 0.0050, the adhesion between the TiAlCN layer and the tool substrate or the lower layer is improved, and the lubricity is improved. As a result, the impact during cutting is relieved, and as a result, the fracture resistance and chipping resistance of the TiAlCN layer are improved. On the other hand, if the average content ratio y _{avg of the} component C departs from the range of 0 ≦ y _avg ≦ 0.0050, the toughness of the TiAlCN layer is lowered, so that the chipping resistance and chipping resistance are adversely impaired.

3. The crystal grain of the NaCl type face centered cubic structure in the TiAlCN layer If the crystal grain of the NaCl type face centered cubic structure is not contained in the TiAlCN layer, the object of the present invention cannot be achieved. In order to achieve this object, in the longitudinal section (cross section perpendicular to the surface of the tool substrate), the area ratio occupied by the crystal grains of the NaCl type face centered cubic structure is 60% or more, preferably 80% or more, more preferably All the crystal grains (area ratio is 100%) are preferably NaCl-type face-centered cubic structures.

4). Tilt angle distribution of {112} plane of crystal grains having NaCl type face centered cubic structure in the TiAlCN layer:
In the present invention, with respect to the TiAlCN layer, the crystal orientation of crystal grains is analyzed from the longitudinal section direction (normal direction of the tool base surface) using an electron beam backscattering diffractometer, and the crystal with respect to the normal direction of the tool base surface is analyzed. The inclination angle formed by the normal of the {112} plane of the grain is measured, and the inclination angle in the range of 0 to 45 degrees with respect to the normal direction is included in each inclination angle of 0.25 degrees. When the slope angle distribution is obtained by summing up the frequencies existing in each section and obtaining the tilt angle distribution, the highest peak exists in the tilt angle distribution in the range of 0 to 10 degrees, and the frequencies existing in the range of 0 to 10 degrees The total indicates a ratio of 35% or more of the frequency distribution in the tilt angle distribution.
Here, FIG. 2 shows an example of an inclination angle number distribution measured for the coated tool of the present invention. That is, as can be seen from FIG. 2, the inclination angle number distribution has the highest peak in the inclination angle section in the range of 0 to 10 degrees, and the sum of the frequencies existing in the range of 0 to 10 degrees is the inclination. It is a ratio of 35% or more of the whole frequency in the angular frequency distribution.
That is, the coated tool of the present invention has a relatively high orientation in the normal direction of the {112} plane in the TiAlCN layer, and has the highest peak in the tilt angle section within the range of 0 to 10 degrees in the tilt angle number distribution. And the sum of the frequencies existing in the range of 0 to 10 degrees is 35% or more, preferably 40% or more, more preferably 45% or more of the entire frequencies in the inclination angle frequency distribution, Improved wear resistance, toughness, and improved wear resistance against high heat generated during cutting can be exhibited in a well-balanced manner to improve wear resistance and fracture resistance when used for cutting heat-resistant alloys that are highly difficult-to-cut materials.

5. In a crystal grain having a NaCl-type face-centered cubic structure, one of the average grain width W, average aspect ratio A, and equivalent crystal orientation represented by <001> when viewed from the longitudinal section direction Difference in periodic compositional change of Ti and Al along the azimuth and average of maximum and minimum of Al content ratio:
In the present invention, the average grain size width W of the columnar crystals is 0.1 to 2.0 μm and the average aspect ratio A is 2.0 to 2.0 when observed from the longitudinal section direction in the crystal grains having the NaCl type cubic structure. It is desirable to satisfy 10.0. In this way, the crystal grains having the NaCl type cubic structure become columnar crystals of a predetermined shape and exhibit excellent wear resistance. The reason for setting this numerical range is that the average particle width W is less than 0.1 μm, the wear resistance may be reduced, and if it exceeds 2.0 μm, the toughness may be reduced. When the aspect ratio A is less than 2, it may be difficult to form a periodic distribution of the composition to be described later in the crystal grains having the NaCl-type cubic structure. This is because it may be difficult.
Further, there is a periodic composition change of Ti and Al along one of the equivalent crystal orientations represented by <001>, and the difference between the average of the maximum value and the minimum value of the Al content ratio is 0. 0.03 to 0.25 is preferable. That is, when there is a periodic composition change between Ti and Al in the crystal grains, distortion occurs in the crystal grains and the hardness is improved. When the average difference between the maximum value and the minimum value of the Al content ratio (x) is less than 0.03, the distortion is small and there is no sufficient improvement in hardness. If it becomes too large, lattice defects become large and the hardness decreases.

6). In the crystal grains of the NaCl type face-centered cubic structure, the periodic composition change period of Ti and Al along one of the equivalent crystal orientations represented by <001> is in a plane orthogonal to the orientation. In Al content ratio of:
As described above, a change in the periodic content ratio of Ti and Al exists along one of the equivalent crystal orientations represented by <001>, and the period of this change is 3 to 100 nm. desirable. If the period is less than 3 nm, the toughness may decrease, and if it exceeds 100 nm, improvement in hardness may not be expected. Further, the amount of change in Al content (difference between the maximum value and the minimum value) in the direction perpendicular to the direction in which this periodic change exists (that is, the plane having this direction as the normal direction) is 0.01. The following is desirable. If the period and the Al content change, sufficient hardness and fracture resistance can be further improved.
In addition, the schematic diagram which shows this periodic composition change is shown as FIG.

Presence or absence of periodic change in Al content ratio, difference between maximum and minimum values of periodic change, period width,
In addition, the change in the content of the surface perpendicular to the direction in which the periodic change occurs can be determined by observing a minute region of the composite nitride layer or the composite carbonitride layer using a transmission electron microscope (magnification 200000 times). Confirm existence. For example, using energy dispersive X-ray spectroscopy (EDS), surface analysis is performed on a 400 nm × 400 nm region in a cross section (longitudinal cross section) perpendicular to the surface of the tool substrate, and a cubic crystal having a NaCl type face-centered cubic structure is obtained. When a change in color shading is seen in the crystal grains, periodic compositional changes of Ti and Al in TiAlCN exist in the cubic crystal grains. Then, by performing electron beam analysis on the crystal grain, the periodic composition change occurs in one of the equivalent crystal orientations represented by <001> of the crystal grain having the NaCl type face centered cubic structure. And the magnification is set so that a composition change of about 10 cycles from the light and shade is included in the measurement range based on the result of the surface analysis along the direction. A line analysis by EDS is performed in the range of 5 cycles along the normal direction, the difference between the average value of the maximum value and the minimum value of the periodic change in the Al content ratio x is obtained, and further, the 5 cycles The average interval between the maximum values is obtained as the period of periodic composition change of Ti and Al. Then, surface analysis by EDS is also performed on the direction orthogonal to the direction.

7). Lattice constant a of crystal grains of NaCl type face centered cubic structure:
When the TiAlN layer was subjected to an X-ray diffraction test using an X-ray diffractometer and a Cu-Kα ray as a radiation source, the lattice constant a of the crystal grains of the NaCl type face centered cubic structure was obtained. The lattice constant a of cubic TiN (JCPDS00-038-1420) is 0 with respect to the lattice constant aTiN: 4.24173Å of cubic _TiN (JCPDS00-046-1200) and the lattice constant a _{AlN of} 4.0450Å. .05a _TiN + 0.95a _AlN ≤a ≤0.40a _TiN + 0.60a When satisfying the relationship of _AlN , the TiAlN layer has excellent wear resistance by exhibiting higher hardness and high thermal conductivity. In addition, it has excellent thermal shock resistance. Here, the lower limit value 0.05a _TiN + 0.95a _AlN of the above formula is 4.055Å, and the upper limit value 0.40a _TiN + 0.60a _AlN is 4.124Å.

8). Lower layer:
The hard coating layer including the TiAlCN layer of the present invention alone has a sufficient effect, but one or two or more layers of Ti carbide layer, nitride layer, carbonate layer and carbonitride oxide layer are included. When a lower layer made of a compound layer and having a total average layer thickness of 0.1 to 20.0 μm is provided, more excellent characteristics are exhibited in combination with the effects of these layers. However, when a lower layer composed of one or two or more Ti compound layers of Ti carbide layer, nitride layer, carbonate layer and carbonitride layer is provided, the total average layer thickness of the lower layer is 0. When the thickness is less than 1 μm, the effect of the lower layer is not sufficiently achieved. On the other hand, when the thickness exceeds 20.0 μm, the crystal grains are likely to be coarsened and chipping is likely to occur.

9. Upper layer: Ti carbide layer, nitride layer, carbonitride layer, carbonate layer and carbonitride oxide layer, consisting of one or more Ti compound layers, and a total of 0.1 to 20.0 μm It is preferable to provide an upper layer having an average layer thickness because more excellent characteristics are exhibited. Here, if the total average layer thickness is less than 0.1 μm, the effect of providing the upper layer is not sufficiently exhibited, while if it exceeds 20 μm, chipping tends to occur.

10. Deposition method (conditions)
In the TiAlCN layer of the present invention, the reaction gas for forming the TiAlCN layer is formed on the tool base or the lower layer, which is at least one of the Ti carbide layer, nitride layer, carbonate layer and carbonitride layer, under predetermined conditions. To obtain the film. As a method for controlling the tilt angle of the TiAlCN layer, for example, a TiCN layer having an average layer thickness of 1.5 to 3.5 μm is formed as a base layer for forming the TiAlCN layer.
For example,% representing gas composition is volume%,
(1) Underlayer (TiCN layer)
Reaction _{gas: CH 3 CN: 0.4~0.8%,} TiCl 4: 2.0~3.5%, N 2: 20.0~30.0%, H 2: remainder Pressure of reaction atmosphere: 7. 0 kPa
Reaction atmosphere temperature: 800-870 ° C
(2) TiAlCN layer gas group A: NH ₃ : 0.8 to 1.6%, H ₂ : 35.0 to 40.0%
Gas group B: AlCl ₃ : 0.5 to 0.7%, Al (CH ₃ ) ₃ : 0.00 to 0.08%, TiCl ₄ : 0.1 to 0.3%, N ₂ : 0.0 ˜10.0%, H ₂ : remaining (% in gas group A and gas group B is relative to the sum of gas group A and gas group B gas)
Reaction atmosphere pressure: 4.5 to 5.0 kPa
Reaction atmosphere temperature: 700-900 ° C
Here, the gas group A and the gas group B are separated and supplied in the space in the reaction vessel of the thermal CVD apparatus until just before the film formation object, and the gas group A and the gas just before the film formation object. Allow Group B to mix and react. This is effective for uniformly forming gas species having high reaction activity over the film forming region, and detailed technical contents are disclosed in, for example, Japanese Patent Application Laid-Open No. 2015-131984.

Next, examples will be described.
Here, as a specific example of the coated tool of the present invention, a tool base applied to an insert cutting tool using a WC-based ultrahigh-pressure sintered body will be described. As a tool base, TiCN-based cermet, cBN-based ultrahigh-pressure sintered The same applies to the case where the body is used, and the same applies when applied to a drill or an end mill.

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. After vacuum sintering at a predetermined temperature within a range of ˜1470 ° C. for 1 hour, after sintering, tool bases A to C made of WC-based cemented carbide having an insert shape of SEMT13T3AGSN made by Mitsubishi Materials Corp. Each was manufactured.

Next, a base layer (TiCN layer) and a TiAlCN layer were formed on the surfaces of the tool bases A to C by CVD using a CVD apparatus, and the inventive coated tools 1 to 10 shown in Table 6 were obtained.
The film formation conditions are as described in Tables 2 and 3, and are generally as follows.
(1) Underlayer (TiCN layer)
_{CH 3 CN: 0.4~0.8%, TiCl} 4: 2.0~3.5%, N 2: 20.0~30.0%, H 2: remainder Pressure of reaction atmosphere: 7.0 kPa
Reaction atmosphere temperature: 800-870 ° C
(2) TiAlCN layer gas group A: NH ₃ : 0.8 to 1.6%, H ₂ : 35.0 to 40.0%
Gas group B: AlCl ₃ : 0.5 to 0.7%, Al (CH ₃ ) ₃ : 0.00 to 0.08%, TiCl ₄ : 0.1 to 0.3%, N ₂ : 0.0 ~10.0%, _{H 2:} remainder pressure of reaction atmosphere: 4.5～5.0KPa
Reaction atmosphere temperature: 700-900 ° C
The gas group A and the gas group B are separated and supplied in the space inside the reaction vessel of the thermal CVD apparatus until just before the film formation object, and the gas group A and the gas group B are just before the film formation object. A mixture and a reaction were used, and those described in JP-A-2015-131984 were used.
In the coated tools of the present invention, only the lower layer shown in Table 5 or the lower layer and the upper layer were formed according to the film forming conditions shown in Table 4 for 1 to 10 of the present invention.

For comparison purposes, a hard coating layer including a TiAlCN layer shown in Table 6 is formed by vapor deposition on the surfaces of the tool bases A to C according to the conditions shown in Tables 2 and 3 for comparative coating. Tools 1-10 were manufactured.
In addition, about the comparison coating tools 1-10, according to the formation conditions shown in Table 4, only the lower layer shown in Table 5, or the lower layer and the upper layer were formed.

For the hard coating layers of the inventive coated tools 1 to 10 and the comparative coated tools 1 to 10, the average Al content ratio x and the average C content ratio y were calculated using the method described above. In addition, in each inclination angle number distribution formed by the normal of the {112} plane with respect to the normal of the substrate surface, it is confirmed whether the maximum peak of the inclination angle exists at 0 to 10 degrees, and the inclination angle is The ratio of the frequency existing within the range of 0 to 10 degrees was determined. Further, the presence / absence of a period along the equivalent orientation represented by <001> of the composition change of Ti and Al, the difference between the average of the maximum value and the average of the minimum value of the Al content ratio, the period width, The change in the Al content ratio in the plane perpendicular to the orientation was also measured. In addition, the ratio of crystal grains having NaCl-type face-centered cubic structure, the lattice constants of TiN and AlN having NaCl-type face-centered cubic structure, and present at the grain boundaries of columnar crystals having NaCl-type face-centered cubic structure The area ratio of crystal grains having a fine particle diameter was measured.
The average layer thickness was determined by observing the longitudinal section of each constituent layer using a scanning electron microscope (5000 times magnification), and measuring and averaging the five layer thicknesses within the observation field.
These results are summarized in Table 6. In addition, although not described in Table 6, it is confirmed that the area ratio of the NaCl type face centered cubic structure is 60% or more in any of the invention coated tools 1 to 10 and the comparative coated tools 1 to 10. .

Subsequently, with respect to the inventive coated tools 1 to 10 and comparative coated tools 1 to 10, both are heat-resistant alloy, Ni-19Cr-, in a state of being clamped by a fixing jig at the tip of a cutter made of tool steel having a cutter diameter of 125 mm. A wet face milling and center-cut cutting test of the age-hardened material of 19Fe-3Mo-0.9Ti-0.5Al-5.1 (Nb + Ta) alloy was performed, and the flank wear width of the cutting edge was measured.
Cutting test: wet face milling, center-cut cutting work material: heat-resistant alloy Block material rotation speed of width 100 mm, length 400 mm: 153 min ⁻¹
Cutting speed: 60 m / min
Cutting depth: 1.0mm
Single blade feed amount: 0.15 mm / blade cutting time: 8 minutes Table 7 shows the results of the cutting test. In addition, about the comparison coated tools 1-10, since it reached the lifetime due to chipping generation | occurrence | production, the time until it reaches a lifetime is shown.

From the results shown in Table 7, the inventive coated tools 1-10 are
(A) The hard coating layer has an average layer thickness of 1.0 to 20.0 μm: (Ti _1-x Al _x ) (C _y N _1-y ), X _avg and Y _avg are 0 satisfy _{.60 ≦ X avg ≦ 0.95,0 ≦ Y} avg ≦ 0.0050,
(B) including a crystal grain of composite nitride or composite carbonitride having a NaCl-type face-centered cubic structure;
(C) The inclination angle formed by the normal line of the {112} plane that is the crystal plane of the crystal grain is measured, and the inclination angle is within a range of 0 to 45 degrees with respect to the normal direction of the surface of the tool base. In the inclination angle distribution obtained by dividing the inclination angle at 0.25 degree pitch and counting the frequencies existing in each division, it is the highest in the inclination angle division within the range of 0 to 10 degrees. The sum of the frequencies existing within the range of 0 to 10 degrees is 35% or more of the entire frequencies in the tilt angle frequency distribution, with the presence of the peak,
(D) The crystal grains have a columnar structure having an average grain width W of 0.1 to 2.0 μm and an average aspect ratio A of 2.0 to 10.0, and Ti and Al in the crystal grains A periodic composition change exists along one of the equivalent crystal orientations represented by <001> of the crystal grains, and the difference between the average of the maximum value and the average of the minimum value of the Al content is 0. .03-0.25,
Satisfying this, there is no occurrence of chipping in high-speed continuous cutting of heat-resistant alloys that are difficult to cut, and exhibits excellent cutting performance over a long period of time.
On the other hand, the comparative coated tools 1 to 10 that do not satisfy the provisions of the present invention have chipping in high-speed continuous cutting of heat-resistant alloys that are difficult to cut, and have reached the service life in a short time.

  As described above, the coated tool of the present invention can be used as a coated tool for high-speed interrupted cutting even in high-speed interrupted cutting of a heat-resistant alloy, and exhibits excellent wear resistance over a long period of time. Therefore, it is possible to sufficiently satisfy the demand for higher performance of the cutting device, labor saving and energy saving of the cutting work, and further cost reduction.

Claims (5)

In a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool base composed of any of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh-pressure sintered body,
(A) The hard coating layer includes at least a composite nitride layer or composite carbonitride layer of Ti and Al having an average layer thickness of 1.0 to 20.0 μm, and the composite nitride layer or the composite carbonitride layer Is represented by the composition formula: (Ti _1-x Al _x ) (C _y N _1-y ), it occupies the total amount of Ti and Al in the composite nitride layer or the composite carbonitride layer. The average content ratio x _avg , and the average content ratio y _avg (where x _avg and y _avg are atomic ratios) in the total amount of C and N in C of the composite nitride layer or the composite carbonitride layer are Satisfying 0.60 ≦ x _avg ≦ 0.95 and 0 ≦ y _avg ≦ 0.0050, respectively.
(B) The composite nitride layer or the composite carbonitride layer includes at least crystal grains of a composite nitride or composite carbonitride having a NaCl-type face-centered cubic structure,
(C) With respect to the composite nitride layer or the composite carbonitride layer, an electron beam backscattering diffractometer is used to change the crystal orientation of the crystal grains in the longitudinal section direction of the composite nitride layer or the composite carbonitride layer. The inclination angle formed by the normal of the {112} plane, which is the crystal plane of the crystal grain, is measured with respect to the normal direction of the surface of the tool base, and the surface of the tool base out of the inclination angles In the inclination angle number distribution obtained by dividing the inclination angle within the range of 0 to 45 degrees with respect to the normal direction of each for each pitch of 0.25 degrees and totaling the frequencies existing in each division The highest peak exists 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 35% or more of the entire degrees in the inclination angle frequency distribution. ,
(D) When the composite nitride layer or the composite carbonitride layer is observed from the longitudinal sectional direction, the average grain width W of the crystal grains is 0.1 to 2.0 μm, and the average aspect ratio A is 2.0 to It has a columnar structure of 10.0, and a periodic composition change of Ti and Al in the crystal grains exists along one of the equivalent crystal orientations represented by <001> of the crystal grains And the difference of the average of the maximum value of the said content rate of Al and the average of minimum value is 0.03-0.25, The surface coating tool characterized by the above-mentioned.   A periodic composition change of Ti and Al in the crystal grains exists along one orientation of the equivalent crystal orientation represented by <001> of the crystal grains, and the period in the orientation is 3 to 100 nm, 2. The surface-coated tool according to claim 1, wherein the amount of change in the content ratio of Al is 0.01 or less in a plane perpendicular to the orientation. The lattice constant a of the crystal grains is 0.05a _TiN + 0.95a _AlN ≦ a ≦ 0.40a _TiN + 0.60a _AlN with respect to the lattice constant a _TiN of cubic _TiN and the lattice constant a _AlN of cubic _AlN . The surface-coated tool according to claim 1, wherein the surface-coated tool is satisfied.   The composite nitride layer or the composite carbonitride layer is made of only Ti or Al composite nitride or the composite carbonitride crystal grains having a NaCl-type face-centered cubic structure. The surface covering tool in any one of 1-3.   It consists of one or two or more Ti compound layers of Ti carbide layer, nitride layer, carbonate layer and carbonitride layer between the tool base and the hard coating layer, The surface-coated tool according to any one of claims 1 to 4, wherein a lower layer having a total average layer thickness of 20.0 µm is present.

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