JP2019084671A - Surface-coated cutting tool having hard coating layer exerting excellent chipping resistance and wear resistance - Google Patents

Abstract

To provide a surface-coated cutting tool exerting excellent chipping resistance and wear resistance over a long term use even in the case of using for the high-speed intermittent cutting or the like of an alloy steel and the like.SOLUTION: An objective surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool substrate is characterized in that (a) the hard coating layer includes at least a Ti-Al composite carbonitroxide layer having an average layer thickness of 3.0-20.0 μm; (b) the Ti-Al composite carbonitroxide layer includes crystal grains having an NaCl type face-centered cubic structure; and (c) the above carbonitroxide layer satisfies 0.60≤x≤0.95, 0.010≤y≤0.050 and 0.060≤z≤0.100 when representing the composition of the layer by a compositional formula: (TiAl)(CNO).SELECTED DRAWING: Figure 1

Description

  The present invention is a high-speed interrupted cutting process in which an impactive load acts on the cutting edge while generating high heat such as alloy steel, and the hard coating layer has excellent chipping resistance and wear resistance. The present invention relates to a surface-coated cutting tool (hereinafter sometimes referred to as a coated tool) that exhibits excellent cutting performance over long-term use.

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 ultrahigh-pressure sintered body is generally used. There is a coated tool in which a Ti—Al-based composite nitride layer is coated by PVD or CVD as a hard coating layer on the surface of the tool base (hereinafter referred to as generically referred to as tool base). It is known to exhibit excellent wear resistance.
However, although the coated tool on which the conventional Ti-Al composite nitride layer or composite carbonitride layer is formed is relatively excellent in wear resistance, it is abnormal such as chipping when used under high speed interrupted cutting conditions. Various proposals have been made for the improvement of the hard coating layer, since it is prone to wear and tear.

For example, in Patent Document 1, the surface of a cutting tool substrate made of cemented carbide, cermet or cBN-based ultrahigh-pressure sintered body,
Composition formula: (Al _1-x Ti _x ) N (x is 0.40 to 0.60), surface-coated cutting tool formed by vapor deposition of composite nitride layer having an average layer thickness of 1 to 10 μm, the following (a), A surface-coated cutting tool has been proposed which exhibits excellent fracture resistance in high-speed heavy cutting by vapor deposition of a hard coating layer composed of a composite nitride layer satisfying (b).
(A) With regard to the inclination angle formed by the crystal orientation <111> of the crystal grains with respect to the normal direction of the surface polishing surface, the measured inclination angle within the range of 0 to 55 degrees with respect to the normal direction is a pitch of 0.25 degree When dividing the frequency into each division and totaling the frequency present in each division, the area ratio of crystal grains in which crystal orientation <111> exists in the inclination angle division within the range of 0 to 15 degrees is 50% of the total crystal grain area (B) The ratio of small angle grain boundaries where the angle between adjacent crystal grains forming the grain boundaries is more than 0 ° and not more than 15 ° is 50% or more of the total grain boundaries

  Further, in Patent Document 2, when the diffraction intensity of the (111) plane in the X-ray diffraction of the coating layer is I (111) and the diffraction intensity of the (200) plane is I (200), I (200) / I A surface-coated end mill has been proposed in which the value of (111) is 2.0 or less, and on the above-mentioned coating layer, a composite nitroxide of Ti and Al is further coated.

  In addition, Patent Document 3 proposes a coated cutting tool in which the coating layer contains a refractory layer containing a plurality of subphase groups including aluminum oxynitride or composite aluminum oxynitride and alumina or composite alumina. .

JP 2008-264890 A Unexamined-Japanese-Patent No. 9-291353 gazette JP, 2015-47690, A

In recent years, there is a strong demand for labor saving and energy saving in cutting processing, and along with this, cutting processing tends to be faster and more efficient, and the coated tools are more resistant to chipping, chipping, While the abnormal damage resistance such as peeling resistance is required, excellent wear resistance is required over a long period of use.
However, the coated tools proposed in Patent Documents 1 to 3 are resistant to chipping and wear in high speed interrupted cutting in which an impactive load acts on the cutting edge while generating high heat such as alloy steel. It is not yet sufficient, and it can not be said that it has a satisfactory tool life.

  Therefore, the present invention solves the above-mentioned problems and provides a coated tool exhibiting excellent chipping resistance and wear resistance over long-term use even when subjected to high-speed interrupted cutting of alloy steel or the like. With the goal.

  The inventor of the present invention aims to improve the chipping resistance and wear resistance of a coated tool provided with a hard coating layer including at least a composite carbonitride layer of Ti and Al (sometimes expressed as TiAlCN) on a tool substrate. In particular, the present inventors diligently studied how positive addition of a trace amount of O not only to the surface of the hard coating layer but also to the thickness direction affects the improvement of the chipping resistance and the abrasion resistance.

That is, although the TiAlCN film obtained by adding a small amount of C to the TiAlN film has a lattice distortion due to the addition of C compared to the TiAlN film, the hardness is improved. In addition, if a predetermined distribution of a trace amount of O is given in the thickness direction of the coating, the oxidation resistance of the TiAlCN coating itself is improved, and the chipping resistance and the wear resistance in high speed interrupted cutting are more enhanced. Further improvement was found (hereinafter, a layer in which O is positively added to TiAlCN may be referred to as "TiAlCNO layer").
In Patent Document 2, when oxygen is contained in the outermost layer Ti / Al composite nitride or carbonitride, the coefficient of friction can be reduced and the tool life can be improved by the reduction of cutting heat, Zr, It is possible to improve the oxidation resistance by replacing one or more components of Hf, Y, Si, W, and Cr in the range of 0.05 to 60 at% with respect to Ti, respectively. Although described, the former does not mention improvement in oxidation resistance, and does not disclose even a guideline for the amount of oxygen to be contained, and the latter shows improvement in oxidation resistance against Ti. In addition, it is described that it is brought about by replacement of Zr etc., and in any case that TiAlCNO is formed in any part of the normal direction of the tool substrate surface by the active addition of a trace amount of O. Oxidation resistance are those which do not even suggest the knowledge to improve I.

The present invention was made based on the above findings, and
“(1) Surface coated cutting in which hard coating layer is provided on the surface of a tool base made of tungsten carbide base cemented carbide, titanium carbonitride base cermet or cubic boron nitride base ultrahigh pressure sintered body In the tool
(A) The hard coating layer at least includes a composite carbon oxynitride layer of Ti and Al having an average layer thickness of 3.0 to 20.0 μm,
(B) The composite carbonitrid oxide layer of Ti and Al includes grains having a face-centered cubic structure of NaCl type,
(C) Composition The composition of the composite oxycarbonitride layer of the Ti and Al _{formula: (Ti 1-x Al x} ) (C y N 1-y-z O z) when expressed in, Al Ti and Al The average content ratio x in the total amount of C, the average content ratio y in the total amount of C, N and O in C, and the average content ratio z in the total amount of C, N and O in O (where x, x, and y and z each satisfy an atomic ratio of 0.60 ≦ x ≦ 0.95, 0.010 ≦ y ≦ 0.050, 0.060 ≦ z ≦ 0.100.
A surface coated cutting tool characterized in that.
(2) The composite carbonitrid oxide layer of Ti and Al is characterized in that the ratio of grains of Ti and Al composite carbonitrid oxide having a face-centered cubic structure of NaCl type is 60 area% or more. The surface-coated cutting tool according to (1).
(3) Ti adjacent to and immediately below the composite carbonitride oxide layer of Ti and Al, Ti of an average layer thickness of 0.05 to 1.00 μm different in composition from the composite carbonitride oxide layer of Ti and Al And a lower layer of complex carbon-nitric oxide of aluminum,
The composition of the composite oxycarbonitride lower layer composition _{formula: (Ti 1-s Al s} ) when expressed in _{(C t N 1-t-} u O u), the mean occupying the total amount of Ti and Al in the Al The content ratio s, the average content ratio t in the total amount of C, N and O in C, and the average content ratio u in the total amount of C, N and O in O (however, all of s, t and u are The atomic ratio) satisfies 0.00 <s <x, 0.000 <t ≦ 0.050, and 0.000 <u ≦ 0.100, respectively.
The surface-coated cutting tool according to (1) or (2), characterized in that
(4) It consists of one or more layers of a carbide layer, a nitride layer, a carbonitride layer, a carbon oxide layer, and a carbon oxynitride layer of Ti adjacent to and immediately above the tool substrate, The surface-coated cutting tool according to any one of (1) to (3), which has a Ti compound layer of 0.1 to 20.0 μm as a total average layer thickness.
(5) A method comprising at least a layer having an aluminum oxide layer having an average layer thickness of 1.0 to 25.0 μm on the composite carbonitriding oxide layer of Ti and Al. The surface-coated cutting tool according to any one of 4).
(6) The composite carbonitrid oxide layer of Ti and Al is bisected in the layer thickness direction, the average content ratio of O in the tool substrate side region is z _a , and the average content ratio of O in the tool surface side region is The surface-coated cutting tool according to (1) to (4), wherein z _a <z _b, where z _b (where both z _a and z _b are atomic ratios).
(7) In the composite carbonitriding oxide layer of Ti and Al, the content ratio of O to C, N and O in the total amount of the layer continuously extends from the tool base toward the tool surface in the layer thickness direction of the layer. The surface-coated cutting tool according to (6), which is characterized in that it increases. "
It is.

The present invention relates to a surface-coated cutting tool in which a hard coating layer is provided on the surface of a tool substrate, the hard coating layer comprising at least a TiAlCNO layer having an average layer thickness of 3.0 to 20.0 μm. _{formula: (Ti} 1-x _{Al x)} when expressed in _{(C y N 1-y-} z O z), the average content x occupying the total amount of Ti and Al of Al, C and C, N and O The average content ratio y in the total amount and the average content ratio z in the total amount of C, N and O of O (where each of x, y and z is an atomic ratio) are each 0.60 ≦ x 0.95, 0.010 ≦ y ≦ 0.050, and 0.060 ≦ z ≦ 0.100. That is, by actively adding a small amount of O, the hard coating layer including the TiAlCNO layer is enhanced in hardness and oxidation resistance, and even when subjected to high-speed interrupted cutting of alloy steel, etc. The coated tool of the invention has excellent chipping resistance and exhibits excellent wear resistance over long-term use.
Further, by setting the area ratio of crystal grains having a face-centered cubic structure of NaCl type in the TiAlCNO layer to 60 area% or more, the hardness of the hard coating layer is improved, and more excellent wear resistance is exhibited. .
Furthermore, when the TiAlCNO layer is equally divided in the layer thickness direction, the average content ratio of O in the tool substrate side region is z _a and the average content ratio of the tool surface side region is z _b , z _a <z _b To be satisfied. That is, the active addition of a small amount of O to the TiAlCN layer and the distribution that the O average content ratio of the tool surface side area is higher than the tool base side area makes the tool surface side of the TiAlCNO layer during cutting work An oxide layer is likely to be formed in the region, and the oxide layer serves as a protective layer to improve chipping resistance and chipping resistance and to exhibit excellent chipping resistance.
In addition, by providing a TiAlCNO layer different in composition from the TiAlCNO layer adjacent to the tool base side as a lower layer, the adhesion strength with the hard coating layer is improved and the chipping resistance is further improved. .

It is an example of the schematic diagram of the hard coating layer which concerns on this invention, and the layer in () is provided as needed. It is another example of the schematic diagram of the hard coating layer which concerns on this invention, and the TiAlCNO layer from which the average content rate of oxygen differs in a tool base side and a tool surface side is included, The layer in () is provided as needed. It is a thing.

  The present invention is described in detail below. In addition, when a numerical range is expressed with "-" in this specification and a claim, the range includes the numerical value of an upper limit and a lower limit.

Average layer thickness of TiAlCNO layer:
Hard layer of the present invention, the composition _formula: including at least a TiAlCNO layers represented by _{(Ti 1-x Al x)} (C y N 1-y-z O z). The TiAlCNO layer has high hardness and excellent chipping resistance and abrasion resistance, but the effect is particularly exhibited when the average layer thickness is 3.0 to 20.0 μm. This is because if the average layer thickness is less than 3.0 μm, the wear resistance over a long period of use can not be sufficiently secured because the layer thickness is thin, while if the average layer thickness exceeds 20.0 μm, TiAlCNO The crystal grains of the layer tend to be coarsened and chipping tends to occur.
Therefore, the average layer thickness was determined to be 3.0 to 20.0 μm. More preferably, it is 5.0-15.0 micrometers.

Average composition of TiAlCNO layer:
The composition of the TiAlCNO layer in the present invention is
The average content ratio (hereinafter referred to as “average content ratio of Al”) x in the total content of Ti and Al of Al is
The average content ratio of C to C, N and O in the total amount (hereinafter referred to as “average content ratio of C”) y,
The average content ratio of C to O, the total content of N and O (hereinafter referred to as “the average content ratio of O”) z,
In order to satisfy 0.60 ≦ x ≦ 0.95, 0.010 ≦ y ≦ 0.050, 0.060 ≦ z ≦ 0.100 (where x, y and z are all atomic ratios), respectively. Determined.
The reason is as follows.
When the average content ratio x of Al is less than 0.60, the hardness of the TiAlCNO layer is inferior, and therefore, when it is subjected to high speed intermittent cutting of alloy steel or the like, the wear resistance is not sufficient. If it exceeds 95, the average content of Ti relatively decreases, so embrittlement tends to occur, and the chipping resistance decreases. Therefore, 0.60 ≦ x ≦ 0.95, but more preferably 0.70 ≦ x ≦ 0.90.
Further, the reason why the average content ratio y of C is set to 0.010 ≦ y ≦ 0.050 is because hardness can be improved while maintaining the chipping resistance in the above-mentioned range.
Furthermore, if the average content ratio z of O is less than 0.060, the oxidation resistance is not sufficiently imparted, and if it exceeds 0.100, segregation of the oxide occurs, which is not preferable because the chipping resistance is lowered. .

Area fraction of individual grains with face-centered cubic structure of NaCl type in TiAlCNO layer:
The area ratio of crystal grains having a face-centered cubic structure of the NaCl type in the TiAlCNO layer is preferably 60 area% or more. As a result, the area ratio of crystal grains having a face-centered cubic structure of NaCl type, which is high hardness, becomes relatively high compared to crystal grains of hexagonal crystal structure, and an effect of improving the hardness can be obtained. The area ratio is more preferably 75 area% or more.

Average content ratio of O on the tool substrate side and the tool surface side in the TiAlCNO layer:
In the TiAlCNO layer, in a region obtained by dividing the layer into two in the layer thickness direction, when an average content ratio of O in the tool substrate side region is z _a and an average content ratio of O in the tool surface side region is z _b , z _{By being a} <z _b , an oxide is easily formed in the tool surface side area at the time of cutting, and this oxide serves as a protective layer to improve chipping resistance and chipping resistance. That is, if z _b is smaller than z _a , the formation of the oxide on the tool base side region increases, and the adhesion strength between the TiAlCNO layer and the tool base can not be secured, and the chipping resistance is impaired. The change in the layer thickness direction of the content ratio of O will be described later.
Incidentally, _{z b,} it is desirable that 0.100 _{<z b} ≦ 0.150.

A composite carbonitrided lower layer of Ti and Al different in composition from the TiAlCNO layer and the TiAlCNO layer provided immediately below the TiAlCNO layer:
In the present invention, the lower layer adjacent to and adjacent to the TiAlCNO layer may be a composite carbonitrided lower layer of Ti and Al having a different composition from that of the TiAlCNO layer (hereinafter referred to as “lower TiAlCNO layer”. You may provide "a lower layer."
By providing this lower TiAlCNO layer, it is possible to reliably exhibit better chipping resistance and wear resistance over long-term use.
Here, the composition of the lower TiAlCNO layer is
The average content ratio (hereinafter referred to as “average content ratio of Al”) s in total content of Ti and Al of Al is
The average content ratio of C to C, N and O in the total amount (hereinafter referred to as “average content ratio of C”) t
The average content ratio of C, N and O in the total amount of O (hereinafter referred to as “average content ratio of O”) u is
In each case, 0.00 <s <x, 0.000 <t ≦ 0.050, 0.000 <u ≦ 0.100 (where s, t and u are all atomic ratios) are determined to be satisfied.
The reason is as follows.
By containing Al, the hardness is improved while maintaining the chipping resistance, and when it is smaller than x, the adhesion between the TiAlCNO layer and the lower layer on the tool substrate or the tool substrate is improved, and the peel resistance is improved. . On the other hand, if it is larger than x, the adhesion strength is lowered and the peel resistance is lowered.
In addition, the hardness can be improved by containing C, because the average content ratio t of C is set to 0.000 <t ≦ 0.050, and the average content ratio is in the range of 0.050 or less If it is, it is because hardness can be improved maintaining chipping resistance. Furthermore, when O is contained, the chipping resistance is improved, but when the average content ratio u exceeds 0.100, segregation of the oxide occurs, which is not preferable because the chipping resistance is lowered.
Furthermore, when the layer thickness of the lower TiAlCNO layer is 0.05 to 1.00 μm, the adhesion strength between the TiAlCNO layer and the surface of the tool base is improved, and the chipping resistance is improved. If the thickness is less than 0.05 μm, the effect of the lower TiAlCNO layer can not be sufficiently exhibited. If the thickness is more than 1.00 μm, the adhesion strength with the TiAlCNO layer is reduced, and the chipping resistance is reduced. It was defined as 00 μm.

Change in the layer thickness direction of the O content in the TiAlCNO layer:
The content of O in the TiAlCNO layer is preferably continuously increased in the layer thickness direction from the tool substrate side to the tool surface side. If it is continuously increased, an oxide is more likely to be formed on the tool surface side, and this oxide layer becomes a protective layer to further improve chipping resistance and chipping resistance.
Here, in the present invention, to continuously increase means to measure the content ratio of O every 0.5 μm in the layer thickness direction from immediately above the tool base to the tool surface, and use that value using the least squares method. When linear approximation is performed, it means that a straight line with a positive inclination is obtained in the layer thickness direction from the tool base side toward the tool surface side.

Next, conditions for forming the TiAlCNO layer and the lower TiAlCNO layer of the present invention are, for example, as follows.
Reactive gas composition (% below is% by volume to the total of the gas group A and the gas group B combined)
Gas group A: NH ₃ : 2.0 to 6.0%, H ₂ : 65.0 to 75.0%
Gas group B: AlCl ₃ : 0.6 to 0.9%, TiCl ₄ : 0.2 to 0.3%, CO: 0.5 to 1.0%, N ₂ : 0.0 to 10.0% , H ₂ : the rest,
Reaction atmosphere pressure: 4.5 to 5.0 kPa
Reaction atmosphere temperature: 700 to 900 ° C.
Supply cycle 1.0 to 5.0 seconds Gas supply time per cycle 0.15 to 0.25 seconds Phase difference between the supply of the gas group A and the gas group B 0.10 to 0.20 seconds Addition of CO as a component of B is a feature for producing the coated tool according to the present invention. This CO gas is a source of C and O of the TiAlCNO layer. Incidentally, as a source of C and O, it can also be used CO ₂ gas.
The conditions for forming the lower TiAlCNO layer provided immediately below the TiAlCNO layer of the present invention are as follows, for example.
Reactive gas composition (% below is% by volume to the total of the gas group A and the gas group B)
Gas group A: NH ₃ : 2.0 to 6.0%, H ₂ : 65.0 to 75.0%
Gas group B: AlCl ₃ : 0.2 to 0.5%, TiCl ₄ : 0.3 to 0.5%, CO: 0.0 to 1.0%, C ₂ H ₄ : 0.0 to ₄ . _{0%, N 2: 0.0~10.0%} , H 2: remainder, reaction atmosphere pressure: 4.5～5.0KPa
Reaction atmosphere temperature: 700 to 900 ° C.
Supply cycle 1.0 to 5.0 seconds Gas supply time per cycle 0.15 to 0.25 seconds Phase difference between supply of gas group A and gas group B 0.10 to 0.20 seconds

Further, the conditions for forming a TiAlCNO layer having different average contents of oxygen on the tool base side and the tool surface side of the present invention are as follows, for example. In addition,% of reaction gas composition is volume% with respect to the whole which set gas group A and gas group B together.
1. Tool substrate side area Gas group A: NH ₃ : 2.0 to 5.0%, H ₂ : 65.0 to 75.0%
Gas group B: AlCl ₃ : 0.6 to 0.9%, TiCl ₄ : 0.2 to 0.3%, CO ₂ : 0.0 to 0.6%, N ₂ : 0.0 to 10.0 %, H ₂ : Remaining reaction pressure: 4.5 to 5.0 kPa
Reaction atmosphere temperature: 700 to 900 ° C.
Supply cycle: 1.0 to 5.0 seconds Gas supply time per cycle: 0.15 to 0.25 seconds Phase difference between supply of the gas group A and the gas group B: 0.10 to 0.20 seconds 2. Tool surface area Gas group A: NH ₃ : 2.0 to 5.0%, H ₂ : 65.0 to 75.0%
Gas group B: AlCl ₃ : 0.6 to 0.9%, TiCl ₄ : 0.2 to 0.3%, CO ₂ : 0.7 to 1.0%, N ₂ : 0.0 to 10.0 %, H ₂ : Remaining reaction pressure: 4.5 to 5.0 kPa
Reaction atmosphere temperature: 700 to 900 ° C.
Supply cycle: 1.0 to 5.0 seconds Gas supply time per cycle: 0.15 to 0.25 seconds Phase difference between supply of the gas group A and the gas group B: 0.10 to 0.20 seconds 3. Continuous increase in the content of O in the layer thickness direction from the tool substrate side toward the tool surface side The content ratio of O in the TiAlCNO layer is continuously from the tool substrate side toward the tool surface in the layer thickness direction In order to increase the film formation, film formation is performed while continuously increasing the ratio of CO ₂ gas from the start of film formation to the end of film formation.

Other layers:
The present invention has sufficient chipping resistance and wear resistance by providing the TiAlCNO layer as a hard covering layer, and a lower TiAlCNO layer having a composition different from that of the TiAlCNO layer, but a carbide layer of Ti, a nitride layer, A tool substrate comprising a lower layer comprising a Ti compound layer comprising one or more layers of a carbonitride layer, a carbon oxide layer and a carbon oxynitride layer and having a total average layer thickness of 0.1 to 20.0 μm And / or when at least an aluminum oxide layer is provided as a top layer on the TiAlCNO layer with a total average layer thickness of 1.0 to 25.0 μm (with z _a <z _b Together with the effects exhibited by these layers, at times except for some time, it is possible to exert even better abrasion resistance and thermal stability.
Here, when the total average layer thickness of the lower layer is less than 0.1 μm, the effect of the lower layer is not sufficiently exhibited. On the other hand, when it exceeds 20.0 μm, the crystal grains of the lower layer are easily coarsened and chipping occurs It becomes easy to do. Also, if the total average layer thickness of the upper layer including the aluminum oxide layer is less than 1.0 μm, the effect of the upper layer is not sufficiently exhibited, while if it exceeds 25.0 μm, the crystal grains of the upper layer are easily coarsened. , Prone to chipping.

  The coating tool of this invention WHEREIN: The schematic diagram which laminated | stacked the said each layer is shown in FIG.

  Moreover, in this invention coated tool, the schematic diagram which laminated | stacked the layer from which oxygen concentration differs by the tool base | substrate side and surface area | region side is shown in FIG.

EXAMPLES The coated tool of the present invention will be specifically described by way of examples.
In the following examples, the case where WC-based cemented carbide or TiCN-based cermet is used as a tool substrate is described, but the same applies to the case where a cBN-based ultra-high pressure sintered body is used as a tool substrate.

Example 1
As raw material powders, WC powders, TiC powders, TaC powders, NbC powders, Cr ₃ C ₂ powders and Co powders each having an average particle diameter of 1 to 3 μm are prepared, and these raw material powders are compounded as shown in Table 1 Add to the composition, add a wax, mix in a ball mill in acetone for 24 hours, dry under reduced pressure, press-mold into a green compact of a predetermined shape at a pressure of 98 MPa, and press the green compact in a vacuum of 5 Pa 1370 Vacuum sintered under the condition of holding for 1 hour at a predetermined temperature in the range of 1470 ° C, and after sintering, manufacture tool substrates A to C made of WC base cemented carbide with insert shape of ISO standard SEEN 1203 AFSN respectively did.

Also, as raw material powders, TiCN powder (TiC / TiN = 50/50 by mass ratio), Mo ₂ C powder, ZrC powder, NbC powder, WC powder, Co powder each having an average particle diameter of 0.5 to 2 μm. And Ni powder are prepared, these raw material powders are compounded into 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, this green compact The body was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, a tool base D made of a TiCN-based cermet having an insert shape of ISO standard SEEN 1203 AFSN was produced.

Next, a TiAlCNO layer was formed on the surfaces of these tool bases A to D using a CVD apparatus.
The film formation conditions by CVD are as follows.
The forming conditions A to G shown in Table 4 and Table 5, that is, a gas group A consisting of NH ₃ and H ₂ , a gas group B consisting of AlCl ₃ , TiCl ₄ , CO, N ₂ , H ₂ , and each gas The reaction gas composition (volume% of the total of the gas group A and the gas group B combined as a whole), NH ₃ as gas group A: 2.0 to 6.0%, H ₂ : 65.0 to 75 .0%, AlCl ₃ as gas group B: 0.6 to 0.9%, TiCl ₄ : 0.2 to 0.3%, CO: 0.5 to 1.0%, N ₂ : 0.0 to 10.0%, H ₂ : Remaining, Reaction atmosphere pressure: 4.5 to 5.0 kPa, Reaction atmosphere temperature: 700 to 900 ° C., Supply cycle 1.0 to 5.0 seconds, Gas supply time per cycle 0 And the phase difference between the supply of gas group A and gas group B is 0.10 to 0.20 seconds. Time, was CVD.
The present invention having an average layer thickness shown in Table 7, an average content ratio of Al, an average content ratio x, s, C, an average content ratio y, t, O of z, u by forming a TiAlCNO layer under the above conditions Coated tools 1 to 12 were manufactured.
Moreover, about this invention coated tools 4-9, film-forming of the lower TiAlCNO layer was performed on formation conditions H-J shown by Table 4, Table 5 before the said TiAlCNO layer formation. The lower TiAlCNO layer is formed, for example, of a gas group A consisting of NH ₃ and H ₂ , a gas group B consisting of AlCl ₃ , TiCl ₄ , CO, N ₂ , H ₂ , and reaction gases as a method of supplying each gas. The composition (% by volume based on the total of the gas group A and the gas group B) is NH ₃ as gas group A: 2.0 to 6.0%, H ₂ : 65.0 to 75.0%, gas group B As AlCl ₃ : 0.2 to 0.5%, TiCl ₄ : 0.3 to 0.5%, CO: 0.0 to 1.0%, C ₂ H ₄ : 0.0 to 4.0%, N ₂ : 0.0 to 10.0%, H ₂ : remaining, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 700 to 900 ° C., supply cycle 1.0 to 5.0 seconds, 1 Gas supply time per cycle 0.15 to 0.25 seconds, phase difference of supply of gas group A and gas group B 0.1 It is obtained by forming a film for a predetermined time with 0 to 0.20 seconds.
In the coated tools 6 to 11 of the present invention, the lower layer and / or the upper layer shown in Table 6 were formed under the forming conditions shown in Table 3.

Further, for the purpose of comparison, by forming a film by CVD under the forming conditions A ′ to G ′ shown in Table 4 and Table 5 on the surfaces of the tool substrates A to D, the average layer thickness shown in Table 8 is obtained. Then, a hard coating layer including at least a TiAlCNO layer was vapor deposited to produce a comparative coated tool. Note that by using _C 2 _{H 4} gas instead of CO gas for E'～G', to form a TiAlCN layer. However, since the presence of oxygen is not completely denied, TiAlCNO may be present, and in Table 8, it is described as "TiAlCNO layer".
Further, as with the coated tools 4 to 9 of the present invention, with respect to the comparative coated tools 4 to 9, under the forming conditions H 'to J' shown in Tables 4 to 5, film formation of the lower TiAlCNO layer before forming the TiAlCNO layer Did.
In the same manner as the coated tools 6 to 11 of the present invention, for the comparative coated tools 6 to 11, the lower layer and / or the upper layer shown in Table 6 were formed under the forming conditions shown in Table 3.

  The average layer thickness is determined by using a scanning electron microscope to select a suitable cross-section (longitudinal cross-section) of the constituent layers of the present invention coated tools 1 to 12 and comparative coated tools 1 to 12 in the direction perpendicular to the tool substrate. ) Was selected and observed, and the layer thicknesses at five points in the observation field of view were measured and averaged.

The average content ratio x and s of Al in the TiAlCNO layer is irradiated with an electron beam from the sample longitudinal cross-section side in a sample whose longitudinal cross-section is polished using an electron-probe-micro-analyzer (EPMA) using an electron-probe-micro-analyzer (EPMA). From the 10-point average of the analysis results of the obtained characteristic X-ray, the average content ratio x, s of Al was determined.
About the average content rate y and t of C, it calculated | required by secondary ion mass spectrometry (Secondary-Ion-Mass-Spectroscopy: SIMS). The ion beam was irradiated from the sample surface side to a range of 70 μm × 70 μm, and concentration measurement in the depth direction was performed on the component released by the sputtering action. The average content ratio y, t of C indicates the average value in the depth direction for the TiAlCNO layer and the lower TiAlCNO layer.
However, the average content ratio of C excludes the inevitable content ratio of C which is included even if the gas containing C is intentionally not used as the gas raw material.
With regard to the average content ratios z and u of O, in samples obtained by polishing sample cross sections using Auger Electron Spectroscopy (AES), electron beams are applied to each layer from the longitudinal cross section side to obtain Auger electron obtained. The average content ratio z, u of O was determined from the analysis results of.
Tables 7 and 8 show the values of x, y, z, s, t and u obtained above (x, y, z, s, t and u are all atomic ratios).

  In addition, the area ratio of crystal grains having a face-centered cubic structure of NaCl type in the TiAlCNO layer is 100 μm, the film thickness is 100 μm in the longitudinal cross sectional direction (the direction perpendicular to the longitudinal cross section (parallel to the tool substrate surface)) The direction is a range of sufficient length in the film thickness measurement range, the vertical cross section of the TiAlCNO layer is polished, and an acceleration of 15 kV is applied to the polished surface at an incident angle of 70 degrees using an electron beam backscattering diffraction imager. It was determined by analyzing the crystal structure of each crystal grain based on an electron beam backscattering diffraction image obtained by irradiating an electron beam at an interval of 0.01 μm with an electron beam of voltage of 1 nA at an irradiation current of 1 nA. The results are shown in Tables 7 and 8.

  Next, in a state in which the above various coated tools are clamped by a fixing jig to a tool steel cutter tip having a cutter diameter of 125 mm, the coated tools according to the present invention 1 to 12 and comparative coated tools 1 to 12 will be described below. The dry-type high-speed face milling cutter, which is a type of high-speed interrupted cutting of alloy steel, and a center-cut cutting test are conducted to measure the flank wear width of the cutting edge.

Tool base: WC base cemented carbide, TiCN base cermet,
Cutting test: dry high-speed face milling, center cut cutting,
Work material: JIS · SCM 440 block material of width 100 mm, length 400 mm,
Speed of rotation: 764 min ^-1 ,
Cutting speed: 300 m / min,
Notch: 3.0 mm,
Single blade feed amount: 0.30 mm / blade,
Cutting time: 8 minutes,
(Normal cutting speed: 150 to 200 m / min)
Table 9 shows the results.

Example 2
Prepare WC powder, TiC powder, ZrC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder and Co powder all having an average particle diameter of 1 to 3 μm as raw material powders, Add the wax to the formulation shown in Table 10, add wax, ball mill mix in acetone for 24 hours, dry under reduced pressure, press-form into a green compact of a specified shape with a pressure of 98 MPa, and press this green compact Vacuum sintering under the conditions of 1370 to 1470 ° C. for 1 hour in a vacuum of 5 Pa, and after sintering, apply honing of R: 0.07 mm to the cutting edge to achieve ISO standard Tool substrates α to γ made of WC-based cemented carbide with an insert shape of CNMG 120 412 were manufactured, respectively.

  In addition, as raw material powders, TiCN powder (TiC / TiN = 50/50 by mass ratio), NbC powder, WC powder, Co powder, and Ni powder each having an average particle diameter of 0.5 to 2 μm are prepared, These raw material powders are compounded into the 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 this green compact is subjected to nitrogen of 1.3 kPa Sintered in an atmosphere at a temperature of 1500 ° C. for 1 hour, and after sintering, apply a honing process of R: 0.09 mm to the cutting edge portion to obtain a TiCN group having an insert shape of ISO standard / CNMG 120 412. A tool base δ made of cermet was formed.

Next, using a CVD apparatus on the surfaces of these tool bases α to γ and tool base δ, forming conditions A to G shown in Table 4 and Table 5, that is, a gas group A consisting of NH ₃ and H ₂ and A gas group B consisting of AlCl ₃ , TiCl ₄ , CO, N ₂ and H ₂ , and a reaction gas composition (volume% of the total of the gas group A and the gas group B combined) as a method of supplying each gas, NH ₃ as gas group A: 2.0 to 6.0%, H ₂ : 65.0 to 75.0%, AlCl ₃ as gas group B: 0.6 to 0.9%, TiCl ₄ : 0.2 0.3 0.3%, CO: 0.5 to 1.0%, N ₂ : 0.0 to 10.0%, H ₂ : Remaining, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 700 to 900 ° C., supply cycle 1.0 to 5.0 seconds, gas supply time 0.15 to one cycle .25 seconds, as the phase difference 0.10-0.20 seconds of the feed gas group A and the gas group B, a predetermined time, were CVD.
The present invention having an average layer thickness shown in Table 13, an average content ratio of Al, an average content ratio of y, c, and an average content ratio of y, t, O of z, u by forming a TiAlCNO layer under the above conditions Coated tools 13 to 24 were manufactured.
Further, for the coated tools 16 to 21 of the present invention, the lower TiAlCNO layer was formed under the forming conditions H to J shown in Table 4 and Table 5 before forming the TiAlCNO layer as in Example 1.
With respect to the coated tools 18 to 23 of the present invention, the lower layer and / or the upper layer shown in Table 12 were formed under the forming conditions shown in Table 3.

Further, for the purpose of comparison, the coated tool according to the present invention is also provided on the surface of the tool base α to γ and the tool base δ using a CVD apparatus under the conditions shown in Tables 4 and 5 and the average layer thicknesses shown in Table 14 Similarly, comparative coated tools 13 to 24 shown in Table 14 were produced by vapor deposition of a hard coated layer.
Further, as in the case of the coated tools 16 to 21 of the present invention, with respect to the comparative coated tools 16 to 21, under the forming conditions H 'to J' shown in Tables 4 to 5, the film formation of the lower TiAlCNO layer before forming the TiAlCNO layer Did.
The lower layer and / or the upper layer shown in Table 12 were formed under the forming conditions shown in Tables 3 to 5 for the comparative coated tools 18 to 23 similarly to the coated tools 18 to 23 of the present invention.

  The average layer thickness was determined by observing the cross sections of the respective constituent layers of the coated tools 13 to 24 of the present invention and the comparative coated tools 13 to 24 using a scanning electron microscope (magnification: 5000), and five layer thicknesses in the observation field of view Was measured and averaged.

  Further, as in Example 1, with respect to the TiAlCNO layer and the lower TiAlCNO layer of the coated tools of the present invention 13 to 24 and the comparative coated tools 13 to 24, the average content ratio of Al x, s and C average content ratio y, t The average content ratio z and u of O was measured, and the area ratio of crystal grains having a face-centered cubic structure of NaCl type in the TiAlCNO layer was determined. The results are shown in Tables 13 and 14.

Next, all the coated tools are screwed to the tip of a tool steel tool with a fixing jig, and the coated tools 13 to 24 of the present invention and the comparative coated tools 13 to 24 are shown below. Wet high-speed intermittent cutting tests of carbon steel and cast iron were conducted, and both measured the flank wear width of the cutting edge.
Cutting condition 1:
Tool base: WC base cemented carbide, TiCN base cermet,
Work material: JIS · S55C in the longitudinal direction equally spaced four vertical grooved round bar,
Cutting speed: 330 m / min,
Notch: 2.0 mm,
Feeding: 0.2 mm / rev,
Cutting time: 5 minutes,
(Normal cutting speed is 220m / min),
Cutting condition 2:
Tool base: WC base cemented carbide, TiCN base cermet,
Work material: JIS · FCD 600 longitudinal direction equally spaced four vertical grooved round bar,
Cutting speed: 300 m / min,
Notch: 2.0 mm,
Feeding: 0.2 mm / rev,
Cutting time: 5 minutes,
(Normal cutting speed is 180m / min),
Table 15 shows the results of the cutting test.

Example 3
A CVD apparatus is used on the surfaces of the tool substrates A to D shown in Tables 1 and 2, and under the forming conditions K to N shown in Tables 16 and 17, K1 to M1, that is, NH ₃ and H ₂ Gas group A and gas group B consisting of AlCl ₃ , TiCl ₄ , CO ₂ , N ₂ and H ₂ , and reaction gas composition (% for gas group A and gas group B together as a method for supplying each gas As a gas group A, NH ₃ : 2.5 to 5.0%, H ₂ : 68.0 to 75.0%, and as a gas group B, AlCl ₃ : 0.7 to 0.9) %, TiCl ₄ : 0.2 to 0.3%, CO ₂ : 0.0 to 0.6%, N ₂ : 0.0 to 5.0%, H ₂ : remaining, reaction atmosphere pressure: 4.5 ~ 5.0 kPa, reaction atmosphere temperature: 700 to 900 ° C, supply cycle 1.0 to 3.0 seconds, 1 cycle equivalent The phase difference between the supply of gas group A and gas group B is 0.10 to 0.15 second, and film formation of the tool substrate side area is performed by CVD for a predetermined time. went. Next, in formation symbols K to N indicating formation conditions shown in Tables 16 and 17, K2 to M2, that is, a gas group A consisting of NH ₃ and H ₂ , AlCl ₃ , TiCl ₄ , CO ₂ , N _2, gas group consisting of _{H 2} B, and, as a method of supplying each gas, a reaction gas composition (% is% by volume relative to total combined gas group a and gas group _B), NH 3: 2.5~ 5.0%, H ₂ : 68.0 to 75.0%, AlCl ₃ as gas group B: 0.7 to 0.9%, TiCl ₄ : 0.2 to 0.3%, CO ₂ : 0. 7 to 0.8%, N ₂ : 0.0 to 5.0%, H ₂ : remaining, reaction atmosphere pressure: 4.5 to 5.0 kPa, reaction atmosphere temperature: 700 to 900 ° C., supply cycle 1.0 ~ 3.0 seconds, gas supply time per cycle 0.15 to 0.20 seconds, gas group A and gas group B The film thickness of the tool surface side area was formed by CVD for a predetermined time with a phase difference of 0.10 to 0.15 seconds for the supply of.
In addition, under the forming conditions N shown in Tables 16 and 17, the CO ₂ gas ratio is continuously increased (monotonous increase function is increased) from the film formation start time to the film formation end time, and the layer thickness direction of the TiAlCNO layer Film formation was performed so that the content ratio of O continuously increased from the tool substrate side region toward the tool surface region side (for details, see Tables 16 and 17).
Further, for the coated tools 29 and 30 of the present invention, the lower TiAlCNO layer was formed under the forming conditions H and J shown in Table 4 and Table 5 before forming the TiAlCNO layer as in Example 1.
The lower layers shown in Table 18 were formed under the forming conditions shown in Table 3 for the coated tools 28 to 30 of the present invention.
The present invention having an average layer thickness shown in Table 19, an average content ratio of Al, an average content ratio x of s, C and an average content ratio z of u of t, O by forming a TiAlCNO layer under the above conditions Coated tools 25-30 were manufactured.

Also, for comparison purpose, film formation is performed on the surfaces of the tool substrates A to D by using the CVD apparatus under the forming conditions K ′ to N ′ shown in Table 16 and Table 17 as well, as shown in Table 20. Comparative coated tools 25 to 30 shown in Table 20 were produced by vapor deposition of a hard coated layer in the same manner as the coated tool of the present invention at an average layer thickness.
Further, as in the case of the coated tools 29 and 30 of the present invention, for the comparative coated tools 29 and 30, under the forming conditions H 'and J' shown in Tables 4 to 5, the film formation of the lower TiAlCNO layer before forming the TiAlCNO layer Did.
In the same manner as the coated tools 28 to 30 of the present invention, the lower layers shown in Table 18 were formed under the forming conditions shown in Table 3 for the comparative coated tools 29 to 30 (the lower layer for the comparative coated tool 28) Not provided).

  The average layer thickness is obtained by observing the cross sections of the respective constituent layers of the coated tools 25 to 30 of the present invention and the comparative coated tools 25 to 30 using a scanning electron microscope (magnification: 5000) Was measured and averaged.

In addition, the average content ratio x of Al, the average content ratio y of s and C, the average content ratio z of u of t, and O of the TiAlCNO layer of the coated tools 25 to 30 according to the present invention and the comparative coated tools 25 to 30 are measured. The area ratio of crystal grains having a face-centered cubic structure of NaCl type in the TiAlCNO layer was determined in the same manner as in Examples 1 and 2. Furthermore, the presence or absence of a change in the layer thickness direction of the average content ratio z _a , z _b value of O and the content ratio of O was measured on the tool substrate side and the tool surface side. The results are shown in Tables 19 and 20.

  Next, in a state in which the various coated tools are clamped by a fixing jig to a tool steel cutter tip having a cutter diameter of 125 mm, the coated tools according to the present invention 1 to 4 and 25 to 30 and comparative coated tools 1 to 4 And about 25-30, the dry-type high-speed face milling machine which is 1 type of high-speed interrupted cutting of cast iron shown below, a center cut cutting processing test was implemented, and the flank wear width of the cutting edge was measured. In addition, for the coated tools 25-28 of the present invention and the comparative coated tools 25-28, dry type high speed face milling machine which is a kind of high speed interrupted cutting of alloy steel shown below, center cut cutting processing test is carried out The wear width was measured.

Cutting condition 1:
Tool base: WC base cemented carbide, TiCN base cermet,
Cutting test: dry high-speed face milling, center cut cutting,
Work material: JIS · FCD 600 block material of width 100mm, length 400mm,
Speed of rotation: 764 min ^-1 ,
Cutting speed: 300 m / min,
Notch: 2.0 mm,
Single-edge feed: 0.20 mm / blade,
Cutting time: 8 minutes,
(Normal cutting speed: 180 to 220 m / min)
Cutting condition 2:
Tool base: WC base cemented carbide, TiCN base cermet,
Cutting test: dry high-speed face milling, center cut cutting,
Work material: JIS · SCM 440 block material of width 100 mm, length 400 mm,
Rotation speed: 802 min ⁻¹ ,
Cutting speed: 315 m / min,
Notch: 3.0 mm,
Single-edge feed: 0.20 mm / blade,
Cutting time: 8 minutes,
(Normal cutting speed: 150 to 200 m / min)
Table 21 shows the results.

  From the results shown in Table 9, Table 15, and Table 21, the coated tool of the present invention contains grains having a face-centered cubic structure of the NaCl type in the TiAlCNO layer, and the average content of predetermined Al, average content of C High hardness and high oxidation resistance due to having an average content ratio of O and O. As a result, high speed interrupted cutting with high heat generation and intermittent high impact acting on the cutting edge. Even when used in processing, it exhibits excellent wear resistance over long-term use without chipping and breakage.

  On the other hand, in the TiAlCNO layer, a comparative coated tool which does not satisfy the predetermined average content ratio of Al, the average content ratio of C, and the average content ratio of O in abnormal cutting such as chipping in high speed interrupted cutting It is obvious that the life is reached in a short time by the generation or progress of wear.

  As described above, the coated tool of the present invention can be used not only as a high-speed interrupted cutting of alloy steel but also as a coated tool for various work materials, and exhibits excellent cutting performance over long-term use. Therefore, it is possible to cope with the demand for high performance of the cutting device, labor saving and energy saving of the cutting process, and cost reduction.

Claims (7)

In a surface-coated cutting tool in which a hard coating layer is provided 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,
(A) The hard coating layer at least includes a composite carbon oxynitride layer of Ti and Al having an average layer thickness of 3.0 to 20.0 μm,
(B) The composite carbonitrid oxide layer of Ti and Al includes grains having a face-centered cubic structure of NaCl type,
(C) Composition The composition of the composite oxycarbonitride layer of the Ti and Al _{formula: (Ti 1-x Al x} ) (C y N 1-y-z O z) when expressed in, Al Ti and Al The average content ratio x in the total amount of C, the average content ratio y in the total amount of C, N and O in C, and the average content ratio z in the total amount of C, N and O in O (where x, x, and y and z each satisfy an atomic ratio of 0.60 ≦ x ≦ 0.95, 0.010 ≦ y ≦ 0.050, 0.060 ≦ z ≦ 0.100.
A surface coated cutting tool characterized in that.   The composite oxycarbonitride layer of Ti and Al is characterized in that the ratio of grains of Ti and Al complex oxycarbonitride having a face-centered cubic structure of NaCl type is 60 area% or more. The surface-coated cutting tool according to 1. Adjacent to and immediately below the composite carbonitride oxide layer of Ti and Al, the composite carbonitride oxide layer of Ti and Al has an average layer thickness of 0.05 to 1.00 μm of Ti and Al different in composition. Having a composite carbon-nitrogen oxide lower layer,
The composition of the composite oxycarbonitride lower layer composition _{formula: (Ti 1-s Al s} ) when expressed in _{(C t N 1-t-} u O u), the mean occupying the total amount of Ti and Al in the Al The content ratio s, the average content ratio t in the total amount of C, N and O in C, and the average content ratio u in the total amount of C, N and O in O (however, all of s, t and u are The atomic ratio) satisfies 0.00 <s <x, 0.000 <t ≦ 0.050, and 0.000 <u ≦ 0.100, respectively.
The surface-coated cutting tool according to claim 1 or 2, characterized in that   Adjacent to and immediately above the tool substrate, one or more of a carbide layer, a nitride layer, a carbonitride layer, a carbon oxide layer, and a carbon oxynitride layer of Ti, and a total average layer The surface-coated cutting tool according to any one of claims 1 to 3, characterized by having a Ti compound layer of 0.1 to 20.0 μm in thickness.   The method according to any one of claims 1 to 4, further comprising at least a layer having an aluminum oxide layer having an average layer thickness of 1.0 to 25.0 μm on the composite carbonitride oxide layer of Ti and Al. The surface-coated cutting tool according to claim 1. The composite carbon oxynitride layer of Ti and Al is bisected in the layer thickness direction, the average content ratio of O in the tool substrate side region is z _a , and the average content ratio of O in the tool surface side region is z _b ( The surface-coated cutting tool according to any one of claims 1 to 4, wherein z _a <z _b , where z _a and z _b both represent atomic ratios). In the composite carbon oxynitride layer of Ti and Al, the content ratio of O to the total amount of C, N and O continuously increases from the tool base toward the tool surface in the layer thickness direction of the layer. The surface coated cutting tool according to claim 6, characterized in that:

Images