JP2006231423A - Surface coated cermet cutting tool with hard coating layer exerting excellent chipping resistance in high-speed intermittent cutting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cermet cutting tool with a hard coating layer exerting excellent chipping resistance in high-speed intermittent cutting. <P>SOLUTION: This cutting tool has the hard coating layer formed on a surface of a tool base body. The hard coating layer is constituted of the following (a) to (d) layers: (a) a TiN layer having an average layer thickness of 0.1 to 2 μm as a base adhesive layer, (b) a TiCN layer having an average layer thickness of 3 to 20 μm as a lower layer, (c) a Ti compound layer composed of one or more layers of a TiC layer, a TiN layer, a TiCO layer and a TiCNO layer and having a total average layer thickness of 0.1 to 3 μm as an intermediate layer, and (d) a Al<SB>2</SB>O<SB>3</SB>layer having an average layer thickness of 1 to 15 μm as an upper layer. A modified TiCN layer showing a specific inclination angle frequency distribution graph as the lower layer of the (b) is constituted by interposing a modified WC layer having an average layer thickness of 0.1 to 2 μm and having vertical direction feathery growing structures by an observation by a transmission type electron microscope between the base adhesive layer of the (a) and the lower layer of the (b). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a surface-coated cermet cutting tool (hereinafter referred to as a coated cermet tool) that exhibits excellent chipping resistance with a hard coating layer, particularly in high-speed intermittent cutting of steel or cast iron.

Conventionally, generally on the surface of a substrate (hereinafter collectively referred to as a tool substrate) composed of a tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet. ,
(A) a titanium nitride (hereinafter referred to as TiN) layer formed by chemical vapor deposition having an average layer thickness of 0.1 to 2 μm as a base adhesion layer;
(B) As a lower layer, a chemical vapor deposited titanium carbonitride (hereinafter referred to as TiCN) layer having an average layer thickness of 3 to 20 μm,
(C) Ti carbide (hereinafter referred to as TiC) layer, nitride (hereinafter also referred to as TiN) layer, carbonate (hereinafter referred to as TiCO) layer formed by chemical vapor deposition, all as an intermediate layer, and Ti compound layer composed of one or more layers of carbonitride oxide (hereinafter referred to as TiCNO) and having a total average layer thickness of 0.1 to 3 μm,
(D) As an upper layer, a chemical vapor deposited aluminum oxide (hereinafter referred to as Al ₂ O ₃ ) layer having an average layer thickness of 1 to 15 μm,
A coated cermet tool formed by forming a hard coating layer composed of (a) to (d) above is known, and this coated cermet tool is used for continuous cutting and intermittent cutting of various steels and cast irons, for example. It is also known that
Japanese Unexamined Patent Publication No. 6-31503

In recent years, the performance of cutting machines has been remarkable. On the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting work, and along with this, cutting work tends to be further accelerated. For coated cermet tools, there is no problem when this is used for continuous cutting and interrupted cutting under normal conditions such as steel and cast iron. When it is used for high-speed interrupted cutting that is repeatedly subjected to mechanical impact at a very short pitch, the hard coating layer constituting this has high temperature strength due to the TiCN layer of the lower layer, high temperature hardness due to the Al ₂ O ₃ layer of the upper layer, and Although it has heat resistance, the TiCN layer has insufficient high-temperature strength, so it cannot respond satisfactorily to mechanical impacts. As a result, the hard coating layer has no chipping. Since the grayed (minute chipping) tends to occur, at present, leading to a relatively short time service life.

In view of the above, the inventors of the present invention focused on the TiCN layer, which is the lower layer, in order to improve the chipping resistance of the hard coating layer of the above coated cermet tool. ,
(A) When forming the hard coating layer of the above coated cermet tool with a normal chemical vapor deposition apparatus, after forming the TiN layer of the base adhesion layer as a constituent layer under normal conditions, With a vapor deposition device,
Reaction gas composition - by _{volume%, WF 6: 0.04~0.4%,} CH 3 CN: 0.04~0.4% :, H 2: 40~80%, Ar: the remaining,
Reaction atmosphere temperature: 920-1050 ° C.
Reaction atmosphere pressure: 5 to 30 kPa,
When a tungsten carbide (hereinafter referred to as WC) layer is formed with an average layer thickness of 0.1 to 2 μm under the above conditions, the resulting WC layer (hereinafter referred to as “modified WC layer”) is a transmission electron microscope. As shown in FIG. 1, the transmission electron microscope (magnification: 5) shows the modified WC layer constituting the hard coating layer of the coated cermet tool 4 of the present invention in the example. 1), the upper side of FIG. 1 is the surface side and the lower side is the tool base side], and has a vertical feather-like growth structure.

(B) When a TiCN layer is formed by chemical vapor deposition as a lower layer under a normal condition on the modified WC layer having the vertical feather-like growth structure, the resulting TiCN layer (hereinafter, “modified TiCN”) is formed. Layer ”) is a history action of the modified WC layer interposed as a modified layer, and is a chemical vapor deposition as a lower layer under the same normal conditions on the TiN layer which is a base adhesion layer in the conventional hard coating layer. Compared to the formed TiCN layer (hereinafter referred to as “conventional TiCN layer”), it has a higher high-temperature strength and superior mechanical impact resistance. The coated cermet tool comprising the Al ₂ O ₃ layer as the layer and the modified TiCN layer as the lower layer has excellent chipping resistance even in high-speed intermittent cutting with a severe mechanical impact. Demonstrate and long-term It exhibits a superior wear resistance Te.

(C) Using the field emission scanning electron microscope, the conventional TiCN layer and the modified TiCN layer are within the measurement range of the surface polished surface as shown in the schematic explanatory diagrams of FIGS. 2 (a) and 2 (b). An electron beam is irradiated to each of the crystal grains having a cubic crystal lattice, and an inclination angle formed by a normal of the {112} plane that is a crystal plane of the crystal grain is set with respect to a normal of the surface polished surface. Measured and divided the measured inclination angle within the range of 0 to 45 degrees among the measured inclination angles for each pitch of 0.25 degrees, and the number of inclination angles obtained by totalizing the frequencies existing in each section When a distribution graph is created, the conventional TiCN layer shows an unbiased inclination angle number distribution graph within the range of the measured inclination angle of the {112} plane within the range of 0 to 45 degrees as illustrated in FIG. On the other hand, the modified TiCN layer has 0 to 0 as illustrated in FIG. The highest peak exists in the inclination angle section within the range of 0 degrees, and the total of the frequencies existing in the range of 0 to 10 degrees accounts for 50% or more of the total degrees in the inclination angle frequency distribution graph. Show the angle distribution graph.

(C) The modified TiCN layer as the lower layer is formed by chemical vapor deposition on the modified WC layer having the vertical feather-like growth structure formed as the modified layer as described above. Even if any of the conditions for forming the modified WC layer deviates from the above condition range, the modified WC layer having a vertical feather-like growth structure cannot be formed, and in this case, the range of 0 to 10 degrees. An inclination angle number distribution graph in which the highest peak exists in the inclination angle section and the total of the frequencies existing in the range of 0 to 10 degrees occupies 50% or more of the entire frequency in the inclination angle distribution graph. That is, it is impossible to form a modified TiCN layer having excellent high-temperature strength.
The research results shown in (a) to (c) above were obtained.

The present invention has been made based on the above research results, and on the surface of a tool base composed of a WC-based cemented carbide or TiCN-based cermet,
(A) TiN layer formed by chemical vapor deposition having an average layer thickness of 0.1 to 2 μm as a base adhesion layer,
(B) TiCN layer formed by chemical vapor deposition having an average layer thickness of 3 to 20 μm as a lower layer;
(C) Ti having a total average layer thickness of 0.1 to 3 μm, which is formed of one or more of a TiC layer, a TiN layer, a TiCO layer, and a TiCNO layer, all formed by chemical vapor deposition as an intermediate layer Compound layer,
(D) Al ₂ O ₃ layer formed by chemical vapor deposition having an average layer thickness of 1 to 15 μm as an upper layer,
In the surface-coated cermet cutting tool formed by forming the hard coating layer composed of (a) to (d) above,
Between the base adhesion layer of the above (a) and the lower layer of the above (b), it has an average layer thickness of 0.1 to 2 [mu] m, and has a longitudinal feather shape by observing the longitudinal sectional structure with a transmission electron microscope. A modified WC layer formed by chemical vapor deposition having a growth structure;
And a TiCN layer as a lower layer of (b) above,
Using a field emission scanning electron microscope, each crystal grain having a cubic crystal lattice existing within the measurement range of the surface polished surface is irradiated with an electron beam, and the crystal grain is normal to the surface polished surface. The tilt angle formed by the normal of the {112} plane, which is the crystal plane, is measured, and, among the measured tilt angles, the measured tilt angles within the range of 0 to 45 degrees are classified for each pitch of 0.25 degrees. In addition, in the inclination angle number distribution graph obtained by summing up the frequencies existing in each section, the highest peak exists in the inclination angle section within the range of 0 to 10 degrees and also exists within the range of 0 to 10 degrees. A modified TiCN layer showing a tilt angle frequency distribution graph in which the total frequency to be accounted for 50% or more of the total frequency in the tilt angle frequency distribution graph,
It is characterized by a coated cermet tool that exhibits excellent chipping resistance with a hard coating layer in high-speed intermittent cutting.

Next, the reason why the average layer thickness of the hard coating layer of the coated cermet tool of the present invention is limited as described above will be described below.
(A) TiN layer (base adhesion layer)
The TiN layer has a function of improving the adhesion of the hard coating layer to the surface of the tool substrate, as an underlying adhesion layer, firmly adhering to both the tool substrate and the modified WC layer. If the thickness is less than 0.1 μm, the desired adhesion improving effect cannot be obtained. On the other hand, the average layer thickness is determined to be 0.1 to 2 μm because an average layer thickness of 2 μm is sufficient.

(B) Modified WC layer (modified layer)
The modified WC layer is firmly adhered to both the TiN layer as the underlying adhesion layer and the modified TiCN layer of the lower layer, improving the adhesion of the hard coating layer to the tool substrate surface, as described above. The longitudinal feather-like growth structure that it has has a significant history effect on the properties of the TiCN layer as a lower layer deposited under normal conditions. As a result, the deposited TiCN layer is modified. It has excellent high-temperature strength, that is, the highest peak exists in the inclination angle section within the range of 0 to 10 degrees, and the sum of the frequencies existing in the range of 0 to 10 degrees is the inclination angle number distribution. In the graph, it has an action to show an inclination angle frequency distribution graph occupying a ratio of 50% or more of the entire frequency, but if the average layer thickness is less than 0.1 μm, a desired effect cannot be obtained in the action, On the other hand, if the average layer thickness exceeds 2 μm, this part may act as an embrittlement layer, which causes chipping. Therefore, the average layer thickness is set to 0.1 to 2 μm. .

(C) Modified TiCN layer (lower layer)
As described above, by forming the modified WC layer under the above-described deposition conditions, a vertical feather-like growth structure is provided, and by the hysteresis action by the vertical feather-like growth structure of the modified WC layer, vapor deposition is formed on this. The TiCN layer is modified so that the highest peak of the measured tilt angle appears in the tilt angle section range of 0 to 10 degrees, and the total ratio of the frequencies existing in the tilt angle section of 0 to 10 degrees is An inclination angle number distribution graph showing 50% or more of the entire frequency in the inclination angle number distribution graph is shown, and as a result, the high temperature strength is further improved. However, if the average layer thickness is less than 3 μm, it is desirable. The hard coating layer cannot be provided with excellent high-temperature strength. On the other hand, when the average layer thickness exceeds 20 μm, thermoplastic deformation that causes uneven wear tends to occur, and wear is accelerated. Therefore, the average layer thickness was determined to be 3 to 20 μm.

(D) Ti compound layer (intermediate layer)
The Ti compound layer mainly adheres firmly to both the modified TiCN layer as the lower layer and the Al ₂ O ₃ layer as the upper layer, and thus has an effect of contributing to improved adhesion of the hard coating layer to the tool substrate. However, if the total average layer thickness is less than 0.1 μm, the desired effect of improving the adhesion cannot be obtained. On the other hand, the total average layer thickness is sufficient because the total average layer thickness is 3 μm. Was determined to be 0.1 to 3 μm.

(E) Al ₂ O ₃ layer (upper layer)
The Al ₂ O ₃ layer has excellent high-temperature hardness and heat resistance, and contributes to improving the wear resistance of the hard coating layer. However, if the average layer thickness is less than 1 μm, the hard coating layer has sufficient wear resistance. On the other hand, if the average layer thickness exceeds 15 μm and becomes too thick, chipping tends to occur. Therefore, the average layer thickness is set to 1 to 15 μm.

  In addition, for the purpose of identification before and after the use of the cutting tool, a TiN layer having a golden color tone may be vapor-deposited as necessary as the outermost surface layer of the hard coating layer, but the average layer thickness in this case is It may be 0.1 to 1 μm, and if the thickness is less than 0.1 μm, a sufficient discrimination effect cannot be obtained, while the discrimination effect by the TiN layer is sufficient for an average layer thickness of up to 1 μm.

  The coated cermet tool according to the present invention has excellent high-temperature strength with the modified TiCN layer constituting the lower layer of the hard coating layer even in high-speed intermittent cutting such as steel and cast iron with extremely high mechanical and thermal shock. Since it exhibits chipping resistance, the hard coating layer exhibits excellent wear resistance without occurrence of chipping.

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

WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder, and Co powder all having an average particle diameter of 1 to 3 μm are prepared as raw material powders. These raw material powders were blended into the composition shown in Table 1, added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and pressed into a green compact with a predetermined shape at a pressure of 98 MPa. The green compact was vacuum sintered at a predetermined temperature in the range of 1370 to 1470 ° C. for 1 hour in a vacuum of 5 Pa. After sintering, the cutting edge portion was R: 0.07 mm honing By performing the processing, tool bases A to F made of a WC-base cemented carbide having a throwaway tip shape specified in ISO · CNMG120408 were manufactured.

Further, as raw material powders, TiCN (mass ratio, TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC, all having an average particle diameter of 0.5 to 2 μm. Prepare powder, Co powder, and Ni powder, blend these raw material powders into the composition shown in Table 2, wet mix with a ball mill for 24 hours, dry, and press-mold into a green compact at 98 MPa pressure The green compact is sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1540 ° C. for 1 hour, and after sintering, the cutting edge portion is subjected to a honing process of R: 0.07 mm. Tool bases a to f made of TiCN-based cermet having a chip shape conforming to ISO standards / CNMG 120212 were formed.

Next, on the surface of these tool bases A to F and tool bases a to f, using a normal chemical vapor deposition apparatus, the conditions shown in Table 3 and the target layer thickness shown in Table 5 are used as the base adhesion layer. The modified WC layers (a) to (m), which are modified layers, under the conditions shown in Tables 3 and 4 and the combinations and target layer thicknesses shown in Table 5; A TiCN layer as a lower layer is formed by vapor deposition, and this is used as a modified TiCN layer. Then, under the conditions shown in Table 3, the Ti compound as the intermediate layer and the Al ₂ O ₃ layer as the upper layer are also shown in Table 5. The coated cermet tools 1 to 13 of the present invention were produced by vapor deposition with the combination shown in FIG.

For comparison purposes, Table 3 shows the TiN layer that is the base adhesion layer of the hard coating layer and the TiCN layer that is the lower layer (conventional TiCN layer) with the combinations and target layer thicknesses shown in Table 6. Vapor deposition is performed under the conditions shown in Table 3, and the Ti compound as the intermediate layer and the Al ₂ O ₃ layer as the upper layer are also vapor-deposited with the combination shown in Table 6 and with the target layer thickness. Thus, conventionally coated cermet tools 1 to 13 were produced.

Next, an inclination angle number distribution graph was prepared for each of the modified TiCN layer and the conventional TiCN layer constituting the hard coating layer of the above-described coated cermet tool of the present invention and the conventional coated cermet tool using a field emission scanning electron microscope. .
That is, the tilt angle number distribution graph is set in a lens barrel of a field emission scanning electron microscope with the surfaces of the modified TiCN layer and the conventional TiCN layer being polished surfaces, and 70 ° on the polished surface. An electron backscatter diffraction imaging apparatus is irradiated by irradiating an electron beam with an acceleration voltage of 15 kV at an incident angle of 1 nA with an irradiation current of 1 nA on each crystal grain having a cubic crystal lattice existing within the measurement range of the polished surface. Using a 30 × 50 μm region at an interval of 0.1 μm / step, the inclination angle formed by the normal of the {112} plane, which is the crystal plane of the crystal grain, is measured with respect to the normal of the polished surface. Based on this measurement result, among the measured tilt angles, the measured tilt angles within the range of 0 to 45 degrees are divided for each pitch of 0.25 degrees, and the frequencies existing in each section are tabulated. Created by.

  In the gradient angle distribution graphs of the various modified TiCN layers and the conventional TiCN layers obtained as a result, the {112} plane has the highest peak, and the tilt angle within the range of 0 to 10 degrees. Tables 5 and 6 show the ratios of the existing inclination angle numbers to the inclination angle number distribution graph as a whole.

In each of the above-mentioned various inclination angle number distribution graphs, as shown in Tables 5 and 6, each of the modified TiCN layers of the coated cermet tool of the present invention has a measured inclination angle distribution on the {112} plane of 0 to 10 degrees. In contrast to the slope angle distribution graph, the highest peak appears in the slope angle section within the range of 0 and the ratio of the slope angle numbers existing in the slope angle section within the range of 0 to 10 degrees is 50% or more. In the conventional TiCN layer of the conventional coated cermet tool, the distribution of the measured inclination angle of the {112} plane is unbiased within the range of 0 to 45 degrees, the highest peak does not exist, and the range of 0 to 10 degrees. The inclination angle number distribution graph in which the ratio of the inclination angle numbers existing in the inclination angle section is 30% or less was also shown.
FIG. 3 is a graph showing the distribution of inclination angle numbers of the modified TiCN layer of the coated cermet tool 4 of the present invention, and FIG. 4 is a graph showing the distribution of inclination angle numbers of the conventional TiCN layer of the conventional coated cermet tool 2.

Further, with respect to the above-described coated cermet tools 1 to 13 of the present invention, when the longitudinal section of the modified WC layer, which is a constituent layer of the hard coating layer, was measured using a transmission electron microscope, the modified WC layer was Also showed longitudinal feather-like growth tissue.
Further, regarding the above-described coated cermet tools 1 to 13 and the conventional coated cermet tools 1 to 13, the constituent layers of these hard coating layers are observed using an electron beam microanalyzer (EPMA) and an Auger spectroscopic analyzer ( As a result of observing the longitudinal section of the layer, it was confirmed that each constituent layer had substantially the same composition as the target composition. Furthermore, when the thickness of the constituent layer of the hard coating layer of these coated cermet tools was measured using a scanning electron microscope (similarly longitudinal section measurement), the average layer thickness was substantially the same as the target layer thickness ( Average value of 5-point measurement) was shown.

Next, in the state where each of the various coated cermet tools is screwed to the tip of the tool steel tool with a fixing jig, the present coated cermet tools 1 to 13 and the conventional coated cermet tools 1 to 13 are as follows.
Work material: JIS · SCr420H lengthwise equidistant 4 round bars with vertical grooves,
Cutting speed: 420 m / min,
Cutting depth: 1.2mm,
Feed: 0.23mm / rev,
Cutting time: 10 minutes,
Dry high-speed intermittent cutting test (normal cutting speed is 200 m / min) of alloy steel under the above conditions (cutting condition A),
Work material: JIS · S45C lengthwise equal 4 round grooved round bars,
Cutting speed: 380 m / min,
Cutting depth: 1.2mm,
Feed: 0.22mm / rev,
Cutting time: 10 minutes,
Dry high-speed intermittent cutting test of carbon steel under the conditions (cutting condition B) (normal cutting speed is 200 m / min),
Work material: JIS / FCD450 lengthwise equidistant round bars with 4 vertical grooves,
Cutting speed: 420 m / min,
Incision: 1.5mm,
Feed: 0.32mm / rev,
Cutting time: 10 minutes,
The dry high-speed intermittent cutting test (normal cutting speed is 200 m / min) of ductile cast iron under the above conditions (cutting condition C), and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Table 7.

  From the results shown in Tables 5 to 7, in the coated cermet tools 1 to 13 of the present invention, the lower layer of the hard coating layer is the history action of the modified WC layer that is the modified layer, and the inclination of the {112} plane An inclination angle distribution graph showing the highest peak in the inclination angle section within the angle range of 0 to 10 degrees, and the total ratio of the frequencies existing in the inclination angle section range of 0 to 10 degrees occupying 50% or more. Since the modified TiCN layer has excellent high-temperature strength and excellent chipping resistance even in high-speed intermittent cutting of steel or cast iron, which is composed of the modified TiCN layer shown in FIG. While the occurrence of chipping at the blade is remarkably suppressed and excellent wear resistance is exhibited, the lower layer of the hard coating layer is unbiased when the distribution of measured inclination angles on the {112} plane is within the range of 0 to 45 degrees. A few minutes of tilt angle without the highest peak In the conventional coated cermet tools 1 to 13 composed of the conventional TiCN layer shown in the graph, the mechanical impact resistance of the hard coating layer is insufficient in high-speed intermittent cutting, so chipping occurs at the cutting edge. It is clear that the service life is reached in a relatively short time.

  As described above, the coated cermet tool of the present invention has excellent chipping resistance not only for continuous cutting and interrupted cutting under normal conditions such as various steels and cast iron, but also for high-speed interrupted cutting particularly requiring high-temperature strength. Since it exhibits excellent cutting performance over a long period of time, 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.

It is a longitudinal cross-section structure | tissue photograph (longitudinal feather-like growth structure | tissue photograph) by the transmission electron microscope (magnification: 50,000 times) of the modified WC layer which comprises the hard coating layer of this invention coated cermet tool 4. FIG. It is a schematic explanatory drawing which shows the measurement range of the inclination angle of the {112} plane of the crystal grain in the various TiCN layers which comprise a hard coating layer. It is an inclination angle number distribution graph of the {112} plane of the modified TiCN layer constituting the lower layer of the hard coating layer of the coated cermet tool 4 of the present invention. It is the inclination angle number distribution graph of the {112} plane of the conventional TiCN which comprises the lower layer of the hard coating layer of the conventional coating cermet tool 2. FIG.

Claims (1)

On the surface of the tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) a titanium nitride layer formed by chemical vapor deposition having an average layer thickness of 0.1 to 2 μm as a base adhesion layer;
(B) a titanium carbonitride layer formed by chemical vapor deposition having an average layer thickness of 3 to 20 μm as a lower layer;
(C) As an intermediate layer, all consist of one or more of Ti carbide layer, nitride layer, carbonate layer, and carbonitride layer formed by chemical vapor deposition, and a total of 0.1 to 3 μm A Ti compound layer having an average layer thickness;
(D) As an upper layer, an aluminum oxide layer formed by chemical vapor deposition having an average layer thickness of 1 to 15 μm,
In the surface-coated cermet cutting tool formed by forming the hard coating layer composed of (a) to (d) above,
Between the base adhesion layer of the above (a) and the lower layer of the above (b), it has an average layer thickness of 0.1 to 2 [mu] m, and has a longitudinal feather shape by observing the longitudinal sectional structure with a transmission electron microscope. Modified tungsten carbide layer formed by chemical vapor deposition having a growth structure,
Is interposed as a modified layer, the titanium carbonitride layer as the lower layer of (b),
Using a field emission scanning electron microscope, each crystal grain having a cubic crystal lattice existing within the measurement range of the surface polished surface is irradiated with an electron beam, and the crystal grain is normal to the surface polished surface. The tilt angle formed by the normal of the {112} plane, which is the crystal plane, is measured, and, among the measured tilt angles, the measured tilt angles within the range of 0 to 45 degrees are classified for each pitch of 0.25 degrees. In addition, in the inclination angle number distribution graph obtained by summing up the frequencies existing in each section, the highest peak exists in the inclination angle section within the range of 0 to 10 degrees and also exists within the range of 0 to 10 degrees. A modified titanium carbonitride layer showing an inclination angle distribution graph in which the total frequency to be accounted for 50% or more of the entire frequency in the inclination angle distribution graph,
A surface-coated cermet cutting tool that exhibits excellent chipping resistance with a hard coating layer in high-speed intermittent cutting.

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