JP5939508B2 - A surface-coated cutting tool that exhibits excellent chipping resistance with a hard coating layer in high-speed intermittent cutting - Google Patents

Description

  The present invention is a surface-coated cutting tool that exhibits high chipping resistance with a hard coating layer in high-speed intermittent cutting with high heat generation of alloy steel and the like, and an impact load acting on the cutting edge (hereinafter referred to as “chip coating”). , Referred to as a coated tool).

Conventionally, generally composed of tungsten carbide (hereinafter referred to as WC) based cemented carbide, titanium carbonitride (hereinafter referred to as TiCN) based cermet or cubic boron nitride (hereinafter referred to as cBN) based ultra high pressure sintered body There is known a coated tool in which a Ti—Al based composite nitride layer is formed by physical vapor deposition on a surface of a substrate (hereinafter collectively referred to as a substrate) as a hard coating layer. It is known that it exhibits excellent wear resistance.
However, although the above-mentioned conventional coated tool coated with a Ti-Al based composite nitride layer is relatively excellent in wear resistance, it tends to cause abnormal wear such as chipping when used under high-speed intermittent cutting conditions. Therefore, various proposals for improving the hard coating layer have been made.

For example, Patent Document 1 discloses a composite nitride layer satisfying the composition formula (Ti _1-X Al _X ) N (wherein X is 0.40 to 0.60 in atomic ratio) on the substrate surface. When the crystal orientation analysis by EBSD is performed on the layer, the area ratio of the crystal grains having the crystal orientation <100> in the range of 0 to 15 degrees from the normal direction of the surface polished surface is 50% or more. The area ratio of crystal grains having a crystal orientation <100> within a range of 15 degrees centered on the highest peak existing within a range of 0 to 45 degrees with respect to an arbitrary orientation orthogonal to the normal line of the polished surface is 50. %, A coated tool coated with a hard coating layer composed of a composite nitride layer of Ti and Al showing biaxial crystal orientation has been proposed. This coated tool has excellent resistance to heavy cutting. It is said to exhibit deficiency.

Patent Document 2 discloses that a normal of the {100} plane is applied to the normal of the surface polished surface by applying a bipolar pulse bias to the surface of the substrate and depositing it at a film forming temperature of 750 to 850 ° C. In the inclination angle frequency distribution graph created by measuring the inclination angle formed by, the highest peak is present in the inclination angle section of 30 to 40 degrees, the total frequency is 60% or more of the whole, and the surface polished surface In the constituent atomic shared lattice distribution graph created by measuring the inclination angle formed by the normal of the {112} plane with respect to the normal of Σ3, the highest peak exists at Σ3, and the distribution ratio is 50% or more of the whole A coated tool having a hard coating layer composed of a (Ti _1-X Al _X ) N (X = 0.4 to 0.6) layer is proposed, and this coated tool was excellent in heavy cutting. It is said to exhibit flaw resistance.
However, since the coating tools shown in Patent Documents 1 and 2 form a hard coating layer by physical vapor deposition, the Al content ratio X cannot be increased to 0.6 or more, and the cutting performance is further improved. It is hoped that.

From such a viewpoint, a technique for increasing the Al content ratio X to about 0.9 by forming a hard coating layer by chemical vapor deposition has also been proposed.
For example, Patent Document 3 discloses that the value of the Al content ratio X is 0.65 by performing chemical vapor deposition in a temperature range of 650 to 900 ° C. in a mixed reaction gas of TiCl ₄ , AlCl ₃ , and NH _3. Although it is described that a (Ti _1-X Al _X ) N layer having a thickness of 0.95 can be formed, this document further describes an Al ₂ O ₃ layer on the (Ti _1-X Al _X ) N layer. Therefore, the cutting performance is improved by forming the (Ti _1-X Al _X ) N layer in which the value of X is increased from 0.65 to 0.95. There is no disclosure up to the point of how this will be affected.

For example, in Patent Document 4, chemical vapor deposition without using plasma at a temperature of 700 to 900 ° C. in a mixed reaction gas of TiCl ₄ , AlCl ₃ , NH ₃ , and N ₂ H ₄ , the content ratio X of Al Although it is described that a hard coating layer composed of a cubic (Ti _1-X Al _X ) N layer having a value of 0.75 to 0.93 can be formed, as in Patent Document 3, There is no disclosure about the applicability of.

In Patent Document 5, for the purpose of improving film adhesion and film hardness, at least one layer of the coating layer is a titanium aluminum nitride film (for example, the aluminum content in the film is 0.3 to 60.0% by mass). In this case, the titanium aluminum nitride film is coated with a titanium halide gas, an aluminum halide gas, and an NH ₃ gas at least. The titanium nitride film is formed into a cubic structure and a tensile residual stress is formed by a thermal CVD method using a source gas, and the X-ray diffraction intensity of the titanium aluminum nitride film is (111) plane or A coated tool that is maximized in the (311) plane has been proposed.

JP 2008-100320 A JP 2008-307615 A Special table 2011-516722 gazette US Pat. No. 7,767,320 JP 2001-341008 A

In recent years, there has been a strong demand for energy saving and energy saving in cutting, and along with this, cutting tends to be faster and more efficient, and the coated tool has even more chipping resistance, chipping resistance, Abnormal damage resistance such as peel resistance is required, and excellent wear resistance over long-term use is required.
However, in the coated tools described in Patent Documents 1 and 2, a hard coating layer made of a (Ti _1-X Al _X ) N layer is formed by physical vapor deposition to increase the Al content X in the film. Therefore, for example, when it is subjected to high-speed intermittent cutting of alloy steel, it cannot be said that the chipping resistance is sufficient.

On the other hand, for the (Ti _1-X Al _X ) N layer formed by the chemical vapor deposition method described in Patent Documents 3 and 4, the Al content X can be increased, and a cubic structure is formed. Therefore, although a hard coating layer having a predetermined hardness and excellent wear resistance can be obtained, the adhesion strength with the substrate is not sufficient and the toughness is inferior. When used as a coated tool for cutting, abnormal damage such as chipping, chipping and peeling tends to occur, and it cannot be said that satisfactory cutting performance is exhibited.

  Furthermore, when the coated tool described in Patent Document 5 is used for continuous cutting of carbon steel, it exhibits a certain degree of adhesion and wear resistance. When used for high-speed interrupted cutting of alloy steel or the like on which a heavy load acts, it is impossible to exhibit satisfactory cutting performance over a long period of use due to occurrence of chipping, chipping, peeling, and the like.

  Therefore, the present invention provides a coated tool that exhibits excellent chipping resistance and excellent wear resistance over a long period of use even when subjected to high-speed intermittent cutting of alloy steel, etc. It is intended to do.

From the above-mentioned viewpoint, the present inventors have made a hard coating made of a composite carbonitride of Ti and Al (hereinafter sometimes referred to as “(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 formed by chemical vapor deposition, the following knowledge was obtained.

Tungsten carbide-based cemented carbide (hereinafter referred to as “WC-based cemented carbide”), titanium carbonitride-based cermet (hereinafter referred to as “TiCN-based cermet”), or cubic boron nitride-based ultrahigh pressure sintered body (hereinafter referred to as “TiCN-based cemented carbide”) , Such as a thermal CVD method in which trimethylaluminum (Al (CH ₃ ) ₃ ) is contained as a reactive gas component on the surface of a substrate composed of any one of “cBN-based ultra-high pressure sintered body”. by vapor deposition, as a hard coating layer, the cubic _{(Ti 1-X} Al _X) of the structure (C _{Y N 1-Y)} layer (where, X, Y is an atomic ratio, 0.55 ≦ X ≦ 0 .95, 0.0005 ≦ Y ≦ 0.005), and by adjusting the film forming conditions during vapor deposition, the hard coating layer is crystallized using an electron beam backscatter diffractometer. When analyzing the orientation, When the inclination angle formed by the normal of the {111} plane of the crystal grain with respect to the line direction is measured and the frequency of the measurement inclination angle within the range of 0 to 45 degrees is counted, the inclination within the range of 2 to 12 degrees The highest peak exists in the corner section, and the total frequency within the range of 2 to 12 degrees indicates a ratio of 45% or more of the entire frequency in the inclination angle frequency distribution, and the hard coating layer adheres to the substrate. It has been found that the property is improved and the chipping resistance is improved.

Furthermore, the present inventors have described the crystal planes of crystal grains in the hard coating layer comprising the above (Ti _1-X Al _X ) (C _Y N _1-Y ) layer formed by chemical vapor deposition such as thermal CVD. When the inclination angle formed by the normal lines of the (001) plane and the (011) plane is measured to obtain a constituent atom shared lattice point distribution graph, the distribution ratio of Σ3 in the entire ΣN + 1 on the substrate interface side is reduced ( On the other hand, by increasing the distribution ratio of Σ3 in the entire ΣN + 1 on the surface side of the coating layer (50% or more), the distribution ratio of Σ3 is small on the substrate interface side, and apparently crystals Since the grain size is a fine crystal structure, the coating layer has excellent adhesion, and on the surface side of the coating layer, the distribution ratio of Σ3 is high and the high temperature strength is excellent, so the adhesion of the hard coating layer is improved. Also suitable for high temperature strength To is achieved, it is more of chipping resistance can be improved.

  Therefore, when the coated tool having the hard coating layer as described above is used for, for example, high-speed intermittent cutting of alloy steel, the occurrence of chipping, chipping, peeling, etc. can be suppressed, and it is excellent over a long period of use. The wear resistance can be exhibited.

This invention was made based on the above research results,
“(1) Hard with an average layer thickness of 1 to 20 μm on the surface of a substrate composed of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet or cubic boron nitride-based ultrahigh pressure sintered body A surface-coated cutting tool coated with a coating layer,
(A) the hard coating layer is made of a composite carbonitride layer of Ti and Al stand-cubic structure, the average composition,
_{Formula: (Ti 1-X Al X} ) (C Y N 1-Y)
In this case, the Al content ratio X and the C content ratio Y (where X and Y are atomic ratios) satisfy 0.55 ≦ X ≦ 0.95 and 0.0005 ≦ Y ≦ 0.005, respectively. Satisfied,
(B) For the Ti and Al composite carbonitride layer, the crystal orientation of each crystal grain was analyzed from the longitudinal cross-sectional direction of the Ti and Al composite carbonitride layer using an electron beam backscattering diffractometer. In this case, the inclination angle formed by the normal line of the {111} plane, which is the crystal plane of the crystal grain, with respect to the normal direction of the substrate surface is measured, and 0 to 45 degrees with respect to the normal direction among the measurement inclination angles. When the measured inclination angle within the range is divided for each pitch of 0.25 degrees and the frequencies existing in each division are tabulated, the highest peak is present in the inclination angle division within the range of 2 to 12 degrees, The sum of the frequencies existing within the range of 2 to 12 degrees indicates a ratio of 45% or more of the entire frequencies in the inclination angle frequency distribution,
(C) About the composite carbonitride layer of Ti and Al, using a field emission scanning electron microscope, irradiate each crystal grain existing in the measurement range of the longitudinal section with an electron beam to obtain a normal to the substrate surface. On the other hand, the inclination angle formed by the normal lines of the (001) plane and (011) plane which are crystal planes of the crystal grains is measured. In this case, the crystal grains are composed of Ti, Al, carbon and nitrogen at lattice points. Each of the constituent atoms has a crystal structure of an NaCl type face centered cubic crystal in which each constituent atom exists, and at the interface between adjacent crystal grains based on the measurement tilt angle obtained as a result. The distribution of lattice points (constituent atom shared lattice points) that share one constituent atom between each other is calculated, and N lattice points that do not share constituent atoms between the constituent atom shared lattice points (N is a NaCl type face center) Due to the cubic crystal structure, it will be an even number of 2 or more) In the constituent atom shared lattice point distribution graph showing the distribution ratio of each ΣN + 1 in the whole ΣN + 1 (however, the upper limit value of N is 28 in relation to the frequency) In the range of 0.1 to 0.5 μm from the substrate interface to the inside of the coating layer, the distribution ratio of Σ3 to the entire ΣN + 1 is 20% or less, and from the coating layer surface to 50% of the average thickness of the coating layer A surface-coated cutting tool characterized by showing a constituent atomic shared lattice point distribution graph in which the distribution ratio of Σ3 to the entire ΣN + 1 in the corresponding range is 50% or more and the highest peak exists in Σ3.
(2) the hard coating layer, at least, the manufacturing method of the surface-coated cutting tool according to (1), characterized in that the deposition by chemical vapor deposition containing trimethyl aluminum as a reaction gas component. "
It has the characteristics.

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

The average composition of the cubic composite carbonitride layer of Ti and _{Al ((Ti 1-X Al} X) (C Y N 1-Y) layer):
In the above (Ti _1-X Al _X ) (C _Y N _1-Y ) layer, if the Al content ratio X (atomic ratio) is less than 0.55, the high temperature hardness is insufficient and the wear resistance is reduced. On the other hand, when the value of X (atomic ratio) exceeds 0.95, the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer itself is caused by a decrease in the relative Ti content. Therefore, the value of X (atomic ratio) needs to be 0.55 or more and 0.95 or less.
In the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer, the C component has the effect of improving the hardness, while the N component has the effect of improving the high temperature strength. When the Y content ratio (atomic ratio) is less than 0.0005, high hardness cannot be obtained. On the other hand, when Y (atomic ratio) exceeds 0.005, the high-temperature strength decreases. The ratio was determined to be 0.0005 or more and 0.005 or less.
When the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer having the above composition is formed by the PVD method, the crystal structure is a hexagonal crystal. Since the film is formed by the method, the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer having the above composition can be obtained while maintaining the cubic structure, and the film hardness is reduced. There is no.

Ti and Al cubic carbonitride layer ((Ti _1-X Al _X ) (C _Y N _1-Y ) layer) tilt angle number distribution about {111} plane:
For the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer of the present invention, when the crystal orientation of each crystal grain is analyzed from the longitudinal section direction using an electron beam backscattering diffractometer, An inclination angle (see FIGS. 1A and 1B) formed by a normal line of the {111} plane which is a crystal plane of the crystal grain with respect to a normal line of the substrate surface (a direction perpendicular to the substrate surface in the cross-section polished surface). Measured, and the measured inclination angles within the range of 0 to 45 degrees with respect to the normal direction among the measured inclination angles were divided into pitches of 0.25 degrees, and the frequencies existing in each division were tabulated. When the highest peak exists in the inclination angle section within the range of 2 to 12 degrees, the total of the frequencies existing within the range of 2 to 12 degrees is a ratio of 45% or more of the entire frequencies in the inclination angle distribution. Ti and Al composite charcoal in the case of showing an inclination angle number distribution form Hard layer made of oxide layer has a high hardness while maintaining the cubic structure, moreover, improve the adhesion between the substrate of the hard coating layer by the above-described inclination angle frequency distribution form.
Therefore, even when such a coated tool is used for, for example, high-speed intermittent cutting of alloy steel, the occurrence of chipping, chipping, peeling and the like is suppressed, and excellent wear resistance is exhibited.

  However, if the average thickness of the hard coating layer is less than 1 μm, sufficient wear resistance over a long period of time cannot be secured. On the other hand, if the average thickness exceeds 20 μm, high heat generation occurs. The high-speed interrupted cutting with a tendency to cause thermoplastic deformation, which causes uneven wear. Therefore, the total average layer thickness is set to 1 to 20 μm, preferably 1 to 10 μm.

Further, in this invention, described above for _{(Ti 1-X Al X)} (C Y N 1-Y) layer, crystal grains with a field emission scanning electron microscope, exists within the measurement range of a longitudinal section of the hard coating layer Individually irradiated with an electron beam, the inclination angles formed by the normal lines of the (001) plane and the (011) plane, which are crystal planes of the crystal grains, with respect to the normal line of the substrate surface (FIG. 2 (a), ( In this case, the crystal grains have a NaCl-type face-centered cubic crystal structure in which constituent atoms composed of Ti, Al, carbon, and nitrogen are present at lattice points. Based on the measured tilt angle, distribution of lattice points (constituent atom shared lattice points) in which each of the constituent atoms shares one constituent atom between the crystal grains at the interface between adjacent crystal grains is determined. The case where the constituent atoms are not shared between the constituent atomic shared lattice points is calculated. Constituent atomic shared lattice point form where N points (N is an even number of 2 or more in the crystal structure of NaCl type face-centered cubic crystal) is represented by ΣN + 1, and each ΣN + 1 is an entire ΣN + 1 (however, depending on the frequency) When the constituent atomic shared lattice point distribution graph showing the distribution ratio in the upper limit of N is 28), the entire ΣN + 1 of Σ3 in the range of 0.1 to 0.5 μm from the substrate interface to the inside of the coating layer is obtained. On the other hand, in the range corresponding to 50% of the average layer thickness of the coating layer from the surface of the coating layer, the distribution peak occupies the highest peak in Σ3 and the distribution ratio of Σ3 in the entire ΣN + 1 The constituent atom shared lattice point distribution graph which is 50% or more is shown.
FIGS. 4A and 4B show an example of a constituent atomic shared lattice point distribution graph created for the coated tool of the present invention, and FIG. 4A shows a constituent atomic shared lattice created for the substrate interface side of the hard coating layer. A point distribution graph and (b) show a constituent atom shared lattice point distribution graph created on the surface side of the hard coating layer.
Therefore, the coated tool of the present invention has a small distribution ratio of Σ3 on the substrate interface side, and apparently has a fine crystalline structure, so that the coating layer has excellent adhesion, and on the coating layer surface side, Since the distribution ratio of Σ3 is high, it has excellent high-temperature strength, so it is accompanied by high heat generation, and chipping resistance that is even better in high-speed intermittent cutting of alloy steel and the like that impacts the cutting blade. It exhibits excellent wear resistance over the long-term use without occurrence of abnormal damage such as chipping, chipping and peeling.

_{(Ti 1-X Al X)} (C Y N 1-Y) layer of the present invention, i.e., measuring the angle of inclination is normal of a crystal plane of the crystal grain relative to the normal direction of the substrate surface {111} plane In this case, the highest peak is present in the inclination angle section within the range of 2 to 12 degrees, and the total of the frequencies existing within the range of 2 to 12 degrees is a ratio of 45% or more of the entire frequency. A cubic (Ti _1-X Al _X ) (C _Y N _1-Y ) layer showing an angular number distribution, and the distribution ratio of Σ3 is 20% or less on the substrate interface side. On the surface side of the layer, the formation of a cubic (Ti _1-X Al _X ) (C _Y N _1-Y ) layer showing a constituent atom shared lattice point distribution graph in which the distribution ratio of Σ3 is 50% or more is For example, it can be performed by the following two-stage vapor deposition method.
≪First stage≫
That is, the reaction gas composition (volume%) by the usual chemical vapor deposition method:
_{TiCl 4 0.5~1.5%, Al (CH} 3) 3 0~2%,
AlCl ₃ 6-10%, NH ₃ 13-15%,
N ₂ 6-7%, C ₂ H ₄ 0-1%,
Ar 0-10% H ₂ remaining,
Reaction atmosphere temperature: 700 to 900 ° C.
Reaction atmosphere pressure: 4-5 kPa,
After vapor deposition under the conditions
≪Second stage≫
Reaction gas composition (volume%):
_{TiCl 4 0.5~1.5%, Al (CH} 3) 3 3~5%,
AlCl ₃ 6-10%, NH ₃ 10-12%,
N ₂ 6-7%, C ₂ H ₄ 0-1%,
Ar 0-10% H ₂ remaining,
Reaction atmosphere temperature: 700 to 900 ° C.
Reaction atmosphere pressure: 2-3 kPa,
The conditions of 0.55 ≦ X ≦ 0.95 and 0.0005 ≦ Y ≦ 0.005 (where X and Y are atomic ratios) are satisfied, and In the inclination angle number distribution obtained by measuring the inclination angle formed by the normal of the {111} plane with respect to the line direction, the highest peak exists in the inclination angle section within the range of 2 to 12 degrees, and the 2 to 12 degrees The ratio of the distribution of the number of inclination angles existing in the range is 45% or more, the distribution ratio of Σ3 on the substrate interface side is 20% or less, and the distribution ratio of Σ3 on the coating layer surface side is 50% or more. it is possible to form a cubic structure of _{(Ti 1-X} Al _X) hard coating layer consisting of (C _{Y N 1-Y)} layer.

The coated tool of the present invention is obtained by, for example, (Ti _1-X Al _X ) (C) having a cubic structure by chemical vapor deposition such as thermal CVD containing trimethylaluminum (Al (CH ₃ ) ₃ ) as a reaction gas component. _Y N _1-Y ) layer is formed as a hard coating layer, and the hard coating layer has an inclination angle distribution obtained by measuring the inclination angle formed by the normal of the {111} plane of the crystal grains with respect to the normal direction of the substrate surface. In addition, the highest peak exists in the inclination angle section within the range of 2 to 12 degrees, the total of the frequency ratios within the range of 2 to 12 degrees is 45% or more of the entire frequency, An alloy in which the distribution ratio of Σ3 on the substrate interface side is 20% or less and the distribution ratio of Σ3 on the surface side of the coating layer is 50% or more. For high-speed intermittent cutting of steel Even when it is used, it exhibits excellent wear resistance over a long period of use without causing abnormal damage such as chipping, chipping or peeling.

(A), (b) constitutes the hard coating layer _{(Ti 1-X} Al _X) normal to the (C _{Y N 1-Y)} is a crystal plane of the crystal grains in the layer {111} plane, the substrate It is a schematic explanatory drawing which shows the measurement range of the inclination angle made with respect to the normal line of a surface. (A), (b) is the crystal structure of the NaCl type face centered cubic crystal of the (Ti, Al) (C _Y N _1-Y ) layer constituting the hard coating layer, (001) plane, (011) plane FIG. It is an example of the inclination angle number distribution graph of the {111} plane created about the composite carbonitride of Ti and Al of this invention coated tool. (A), (b) is an example of the constituent atom sharing lattice distribution graph created for the composite carbonitride layer of Ti and Al of the coated tool of the present invention, and (a) shows constituent atom sharing on the substrate interface side. A lattice point distribution graph and (b) show a constituent atom shared lattice point distribution graph on the surface side of the coating layer.

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

As raw material powders, WC powder, TiC powder, ZrC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder all having an average particle diameter of 1 to 3 μm were prepared. Then, after adding wax, ball mill mixing in acetone for 24 hours, drying under reduced pressure, press-molding into a green compact of a predetermined shape at a pressure of 98 MPa. Substrates A to D made of WC-base cemented carbide having an ISO standard SEEN1203AFSN insert shape after vacuum sintering under vacuum at a predetermined temperature in the range of 1370 to 1470 ° C. for 1 hour. Were manufactured respectively.

In addition, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder, all having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and pressed into a compact at a pressure of 98 MPa. The green compact was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1540 ° C. for 1 hour, and after sintering, a substrate made of TiCN-based cermet having an insert shape of ISO standard SEEN1203AFSN d was produced.

Next, on the surfaces of the tool bases A to D and the tool bases a to d, (Ti _1-X Al _X ) (C _Y ) of the present invention is used under the conditions shown in Table 3 using a normal chemical vapor deposition apparatus. The present invention coated tools 1 to 10 shown in Table 5 were manufactured by vapor-depositing N _{1 -Y} ) layers at a target layer thickness.

Further, for the purpose of comparison, similarly to the surface of the tool bases A to D and the tool bases a to d, an ordinary chemical vapor deposition apparatus was used, and under the conditions shown in Table 4, (Ti _1-X Al _X ) of the comparative example. Comparative example-coated tools 1 to 8 shown in Table 6 were manufactured by vapor-depositing (C _Y N _1-Y ) layers at a target layer thickness.

For reference, the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer of the reference example is applied to the surfaces of the tool base A and the tool base a by arc ion plating using a conventional physical vapor deposition apparatus. Were formed by vapor deposition with a target layer thickness to produce reference example coated tools 9 and 10 shown in Table 6.
The conditions for arc ion plating are as follows.
(A) The tool bases A and a are ultrasonically cleaned in acetone and dried, and in the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table in the arc ion plating apparatus. Along with this, an Al-Ti alloy having a predetermined composition is arranged as a cathode electrode (evaporation source),
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 10 ⁻² Pa or less, the inside of the apparatus is heated to 500 ° C. with a heater, and then the tool base that rotates while rotating on the rotary table is −1000 V. A DC bias voltage is applied, and a current of 200 A is passed between a cathode electrode and an anode electrode made of an Al—Ti alloy to generate an arc discharge, thereby generating Al and Ti ions in the apparatus, thereby providing a tool base. Clean the surface with bombard,
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 4 Pa, a DC bias voltage of −50 V is applied to the tool base that rotates while rotating on the rotary table, and A current of 120 A is passed between the cathode electrode (evaporation source) made of the Al—Ti alloy and the anode electrode to generate arc discharge, and the target average composition and target shown in Table 6 are formed on the surface of the tool base. the average layer thickness of _{(Ti 1-X Al X)} (C Y N 1-Y) layer and the vapor deposited,
Reference Example Coated tools 9, 10 were produced.

Moreover, the cross section of each component layer of this invention coated tool 1-10, comparative example coated tool 1-8, and reference example coated tool 9,10 is measured using a scanning electron microscope, and five layers in an observation visual field When the thickness was measured and averaged to determine the average layer thickness, both showed the average layer thickness substantially the same as the target average layer thickness shown in Tables 5 and 6.
Next, with respect to the hard coating layers of the above-mentioned coated tools 1 to 10 of the present invention, the average Al content ratio X, the average C content ratio Y of the hard coating layer, and the inclination formed by the normal of the {111} plane with respect to the normal direction of the substrate surface The ratio (α) of the frequency existing in the range of 2 to 12 degrees in the inclination angle frequency distribution for the corners was measured.
Further, the distribution ratio (β) of Σ3 occupying the entire ΣN + 1 on the substrate interface side (that is, in the range of 0.1 to 0.5 μm from the substrate interface to the inside of the coating layer), the coating layer surface side (that is, coating from the coating layer surface) The distribution ratio (γ) of Σ3 in the entire ΣN + 1 in a range corresponding to 50% of the average layer thickness) was measured.
FIG. 3 shows an example of a {111} plane inclination angle number distribution graph measured for the coated tool of the present invention.
4 (a) and 4 (b) show examples of constituent atomic shared lattice point distribution graphs measured for the coated tool of the present invention.

The specific measurement methods for each of the above are as follows.
The average Al content ratio X and the average C content ratio Y of the hard coating layer were determined by secondary ion mass spectrometry (SIMS, Secondary-Ion-Mass-Spectroscope). The ion beam was irradiated in the range of 70 μm × 70 μm from the sample surface side, and the concentration in the depth direction was measured for the components emitted by the sputtering action. The average Al content ratio X and the average C content ratio Y indicate average values in the depth direction.

In addition, regarding the inclination angle number distribution of the hard coating layer, the column of the field emission scanning electron microscope with the cross section of the hard coating layer made of a composite carbonitride layer of Ti and Al having a cubic structure as a polished surface Each crystal grain having a cubic crystal lattice existing in the measurement range of the cross-sectional polished surface is irradiated with an electron beam with an acceleration voltage of 15 kV at an incident angle of 70 degrees on the polished surface with an irradiation current of 1 nA. Irradiate and use the electron backscatter diffraction imaging apparatus, the normal surface of the substrate surface (with respect to the substrate surface on the cross-section polished surface) at a spacing of 0.1 μm / step with respect to the tool substrate and a length of 100 μm in the horizontal direction. (In the vertical direction), the inclination angle formed by the normal of the {111} plane that is the crystal plane of the crystal grain is measured, and based on the measurement result, 0 to 45 degrees of the measurement inclination angle. The measured tilt angle within the range is 0.25 While dividing into pitches of degrees, the frequencies (α) existing in the range of 2 to 12 degrees were obtained by counting the frequencies existing in each section.

In addition, the constituent atomic shared lattice point distributions on the substrate interface side and the coating layer surface side of the hard coating layer were measured as follows. First, for the substrate interface side, with respect to the normal of the substrate surface in the range of 0.1 to 0.5 μm from the substrate interface of the hard coating layer to the inside of the coating layer (direction perpendicular to the substrate surface on the cross-section polished surface), The inclination angle formed by the normal lines of the (001) plane and the (011) plane, which are the crystal planes of the crystal grains, is measured, and based on the measurement tilt angles obtained as a result, at the interface between adjacent crystal grains, A distribution of lattice points (constituent atom shared lattice points) in which each of the constituent atoms shares one constituent atom among the crystal grains is calculated, and lattice points that do not share constituent atoms between the constituent atom shared lattice points are calculated. When the constituent atomic shared lattice point form of N pieces (N is an even number of 2 or more in the crystal structure of the NaCl type face centered cubic crystal) is represented by ΣN + 1, each ΣN + 1 is an entire ΣN + 1 (however, depending on the frequency) Distribution with an upper limit of 28) By calculating the ratio, a constituent atom shared lattice point distribution graph was created, and the distribution ratio (β) of Σ3 in the entire ΣN + 1 was determined.
Similarly, on the surface side of the coating layer, the distribution ratio (γ) of Σ3 in the cross-sectional polished surface in a range corresponding to 50% of the average layer thickness of the coating layer from the surface of the coating layer was determined.

As for the crystal structure of the hard coating layer, when X-ray diffraction is performed using an X-ray diffractometer and Cu—Kα ray as a radiation source, JCPDS00-038-1420 cubic TiN and JCPDS00-046-1200 cubic crystal A diffraction peak appears between the diffraction angles of the same crystal plane shown in each of AlN (for example, 36.66 to 38.53 °, 43.59 to 44.77 °, 61.81 to 65.18 °). Investigated by confirming.
Table 5 shows the results.

Then, for each of the comparative example coated tools 1 to 8 and the reference example coated tools 9 and 10, as in the present invention coated tools 1 to 10, the average Al content ratio X, the average C content ratio Y of the hard coating layer, The ratio (α) of the frequency existing in the range of 2 to 12 degrees in the tilt angle number distribution with respect to the tilt angle formed by the normal of the {111} plane relative to the normal direction of the substrate surface, the substrate interface side, the coating layer surface side The distribution ratios (β) and (γ) of Σ3 in the entire ΣN + 1 in were measured.
Further, the crystal structure of the hard coating layer was also investigated in the same manner as in the present coated tools 1 to 10.
Table 6 shows the results.

Next, the present coated tools 1 to 10, the comparative coated tools 1 to 8 and the reference in the state where each of the various coated tools is clamped to the tip of the cutter made of tool steel having a cutter diameter of 125 mm by a fixing jig. Example The coated tools 9 and 10 were subjected to the following dry high-speed face milling and center-cut cutting test, which is a kind of high-speed intermittent cutting of alloy steel, and the flank wear width of the cutting edge was measured.
Work material: Block material of JIS / SCM440 width 100mm, length 400mm
Rotational speed: 930 min ⁻¹
Cutting speed: 365 m / min,
Cutting depth: 1.2 mm,
Single blade feed amount: 0.12 mm / tooth,
Cutting time: 8 minutes,
Table 7 shows the results of the cutting test.

As the raw material powder, cBN powder, TiN powder, TiCN powder, TiC powder, Al powder, and Al ₂ O ₃ powder each having an average particle diameter in the range of 0.5 to 4 μm were prepared. The mixture is blended in the composition shown in FIG. 1, wet mixed with a ball mill for 80 hours, dried, and then pressed into a green compact having a diameter of 50 mm × thickness: 1.5 mm under a pressure of 120 MPa. The green compact is sintered in a vacuum atmosphere at a pressure of 1 Pa at a predetermined temperature within a range of 900 to 1300 ° C. for 60 minutes to obtain a presintered body for a cutting edge piece. In addition, Co: 8% by mass, WC: remaining composition, and diameter: 50 mm × thickness: 2 mm, superposed on a WC-based cemented carbide support piece with a normal super-high pressure Insert into the sintering machine and under normal conditions Pressure: 4 GPa, temperature: 1200 ° C. to 1400 ° C. at a predetermined temperature holding time: 0.8 hour sintering, and after sintering, the upper and lower surfaces are polished using a diamond grindstone, and wire discharge It is divided into predetermined dimensions by a processing apparatus, and further Co: 5 mass%, TaC: 5 mass%, WC: remaining composition and shape of JIS standard CNGA12041 (thickness: 4.76 mm × inscribed circle diameter: 12. The brazing part (corner part) of the WC-based cemented carbide insert body having a 7 mm 80 ° rhombus) has a composition consisting of Zr: 37.5%, Cu: 25%, Ti: the rest in mass%. After brazing using a brazing material of Ti-Zr-Cu alloy and having a predetermined dimension, the cutting edge is subjected to honing with a width of 0.13 mm and an angle of 25 °, followed by finishing polishing. ISO standard The tool substrate (a) to (k) two having the insert shape of NGA120412 were produced, respectively.

Then, these tool substrate i ~ the surface of the two, using a conventional chemical vapor deposition apparatus under the conditions shown in Table _{3, (Ti 1-X Al} X) of the present invention (C _{Y N 1-Y)} layer The present invention coated tools 11 to 15 shown in Table 9 were manufactured by vapor-depositing with a target layer thickness.

For the purpose of comparison, the same tool substrate i ~ the surface of the two, using a conventional chemical vapor deposition apparatus under the conditions shown in Table _{4, (Ti 1-X Al} X) of Comparative Example (C _{Y N 1- The} comparative example-coated tools 11 to 14 shown in Table 10 were manufactured by vapor-depositing the _Y ) layer with a target layer thickness.

For reference, the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer of the reference example is formed on the surface of the tool base A by a conventional physical vapor deposition device and arc ion plating with a target layer thickness. The reference example coated tool 15 shown in Table 10 was manufactured by vapor deposition.
The arc ion plating conditions are the same as the conditions shown in Example 1, and the target average composition and target average layer thickness (Ti _1-X shown in Table 10) are formed on the surface of the tool base. An Al _X ) (C _Y N _1-Y ) layer was formed by vapor deposition to produce a reference example coated tool 15.

Moreover, the cross section of each component layer of this invention coated tool 11-15, comparative example coated tool 11-14, and reference example coated tool 15 is measured using a scanning electron microscope, and the layer thickness of five points in an observation visual field is measured. When the average layer thickness was measured and averaged, both average layer thicknesses substantially the same as the target average layer thicknesses shown in Table 9 and Table 10 were obtained.
Next, with respect to the hard coating layers of the above-described coated tools 11 to 15 of the present invention, the average Al content ratio X, the average C content ratio Y of the hard coating layer, and the inclination formed by the normal of the {111} plane with respect to the normal direction of the substrate surface The ratio (α) of the frequency existing within the angle range of 2 to 12 degrees, the distribution ratio (β) of Σ3 occupying the entire ΣN + 1 in the constituent atomic shared lattice point distribution graph on the substrate interface side and the coating layer surface side, (γ The crystal structure was measured using the same method as that shown in Example 1.
Table 9 shows the results.

Then, the comparative coated tools 11 to 14 and the reference coated tool 15 were each made in the same manner as the coated tools 11 to 15 of the present invention, with the average Al content ratio X, the average C content ratio Y, and the substrate surface of the hard coating layer. In the constituent atomic shared lattice point distribution graph on the substrate interface side and the coating layer surface side, the ratio (α) of the power existing in the range of the inclination angle of 2 to 12 degrees formed by the normal of the {111} plane with respect to the normal direction of The distribution ratio (β), (γ) and crystal structure of Σ3 in the entire ΣN + 1 were measured using the same method as that shown in Example 1.
Table 10 shows the results.

Next, in the state where each of the above various coated tools is screwed to the tip of the tool steel tool with a fixing jig, the present coated tools 11 to 15, the comparative coated tools 11 to 14, and the reference coated samples The tool 15 was subjected to the following dry high-speed intermittent cutting test of carburized and quenched alloy steel, and the flank wear width of the cutting edge was measured.
Work material: JIS SCM415 (Hardness: HRC62) lengthwise equidistant four round grooved round bars,
Cutting speed: 230 m / min,
Cutting depth: 0.15mm,
Feed: 0.15mm / rev,
Cutting time: 4 minutes
Table 11 shows the results of the cutting test.

From the results shown in Tables 5 to 7 and Tables 9 to 11, in the present invention coated tools 1 to 15, a (Ti _1-X Al _X ) (C _Y N _1-Y ) layer having a cubic structure is formed, The value of α occupying the entire inclination angle number distribution is 45% or more, the distribution ratio β of Σ3 on the substrate interface side is 20% or less, and the distribution ratio γ3 of Σ3 on the substrate interface side is 50% or more. Excellent chipping and wear resistance due to high-speed intermittent cutting.
On the other hand, all of the comparative example coated tools 1 to 8, 11 to 14 and the reference example coated tools 9, 10, and 15 not only cause abnormal damage such as chipping, chipping, and peeling on the hard coating layer. It is clear that the service life is reached in a relatively short time.

As described above, the coated tool of the present invention can be used not only for high-speed intermittent cutting of alloy steel but also as a coated tool for various work materials, and has excellent chipping resistance over a long period of use. Since it exhibits wear resistance, it can sufficiently satisfy the high performance of the cutting device, the labor saving and energy saving of the cutting work, and the cost reduction.

Claims (2)

A hard coating layer with an average layer thickness of 1 to 20 μm is coated on the surface of a substrate made of tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultrahigh pressure sintered body. A surface-coated cutting tool,
(A) the hard coating layer is made of a composite carbonitride layer of Ti and Al stand-cubic structure, the average composition,
_{Formula: (Ti 1-X Al X} ) (C Y N 1-Y)
In this case, the Al content ratio X and the C content ratio Y (where X and Y are atomic ratios) satisfy 0.55 ≦ X ≦ 0.95 and 0.0005 ≦ Y ≦ 0.005, respectively. Satisfied,
(B) For the Ti and Al composite carbonitride layer, the crystal orientation of each crystal grain was analyzed from the longitudinal cross-sectional direction of the Ti and Al composite carbonitride layer using an electron beam backscattering diffractometer. In this case, the inclination angle formed by the normal line of the {111} plane, which is the crystal plane of the crystal grain, with respect to the normal direction of the substrate surface is measured, and 0 to 45 degrees with respect to the normal direction among the measurement inclination angles. When the measured inclination angle within the range is divided for each pitch of 0.25 degrees and the frequencies existing in each division are tabulated, the highest peak is present in the inclination angle division within the range of 2 to 12 degrees, The sum of the frequencies existing within the range of 2 to 12 degrees indicates a ratio of 45% or more of the entire frequencies in the inclination angle frequency distribution,
(C) About the composite carbonitride layer of Ti and Al, using a field emission scanning electron microscope, irradiate each crystal grain existing in the measurement range of the longitudinal section with an electron beam to obtain a normal to the substrate surface. On the other hand, the inclination angle formed by the normal lines of the (001) plane and (011) plane which are crystal planes of the crystal grains is measured. In this case, the crystal grains are composed of Ti, Al, carbon and nitrogen at lattice points. Each of the constituent atoms has a crystal structure of an NaCl type face centered cubic crystal in which each constituent atom exists, and at the interface between adjacent crystal grains based on the measurement tilt angle obtained as a result. The distribution of lattice points (constituent atom shared lattice points) that share one constituent atom between each other is calculated, and N lattice points that do not share constituent atoms between the constituent atom shared lattice points (N is a NaCl type face center) Due to the cubic crystal structure, it will be an even number of 2 or more) In the constituent atom shared lattice point distribution graph showing the distribution ratio of each ΣN + 1 in the whole ΣN + 1 (however, the upper limit value of N is 28 in relation to the frequency) In the range of 0.1 to 0.5 μm from the substrate interface to the inside of the coating layer, the distribution ratio of Σ3 to the entire ΣN + 1 is 20% or less, and from the coating layer surface to 50% of the average thickness of the coating layer A surface-coated cutting tool characterized by showing a constituent atomic shared lattice point distribution graph in which the distribution ratio of Σ3 to the entire ΣN + 1 in the corresponding range is 50% or more and the highest peak exists in Σ3. The hard coating layer, at least, the manufacturing method of the surface-coated cutting tool according to claim 1, characterized in that the deposition by chemical vapor deposition containing trimethyl aluminum as a reaction gas component.