JP2006159397A - 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: In the surface-coated cermet cutting tool, the hard coating layer is composed of (a) a first adhesive joint layer comprising TiN layer or the like (b) a high-temperature reinforcing layer comprising (Ti, Zr) CN layer satisfying a specific composition formula, (c) a second adhesive joint layer comprising TiCO layer or the like, and (d) a high-temperature reinforcing layer comprising Al<SB>2</SB>O<SB>3</SB>layer on the surface of a tool base substance. The high-temperature reinforcing layer among the hard coating layers is composed of a modified high-temperature reinforcing layer comprising (Ti, Zr) CN layer showing peculiar distribution graph when calculating the distribution of constitutive atoms covalent lattice points by a specified method using a field emission type scanning electron microscope. <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) As a first layer, a chemical vapor deposition formed titanium nitride (hereinafter referred to as TiN) layer and titanium carbonitride (hereinafter referred to as TiCN) layer, or a laminate of both layers, and A first adhesive bonding layer having an average layer thickness of 0.1 to 1 μm;
(B) The second layer is formed by chemical vapor deposition,
Composition formula: (Ti _1-X Zr _X ) CN (wherein X is 0.02 to 0.15 in atomic ratio),
A high-temperature strengthening layer comprising a composite carbonitride of Ti and Zr satisfying the following [hereinafter referred to as (Ti, Zr) CN] layer and having an average layer thickness of 2.5 to 15 μm
(C) As the third layer, either a titanium carbonate (hereinafter referred to as TiCO) layer formed by chemical vapor deposition or a titanium carbonitride oxide (hereinafter referred to as TiCNO) layer, or a laminate of both layers is formed. And a second adhesive bonding layer having an average layer thickness of 0.1 to 1 μm,
(D) As a fourth layer, a high-temperature hard layer comprising an aluminum oxide (hereinafter referred to as Al ₂ O ₃ ) layer formed by chemical vapor deposition and 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
JP 2001-11632 A

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 used for high-speed intermittent cutting in which mechanical impact is repeatedly applied at an extremely short pitch, the hard coating layer constituting this has high-temperature hardness and heat resistance due to the fourth Al ₂ O ₃ layer, The high temperature strength of the second layer of (Ti, Zr) CN due to the high temperature strengthening layer is insufficient, so that it cannot respond satisfactorily to the mechanical shock. As a result, the hard coating layer has Chi Since the ring (small 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 have (Ti, Zr) CN as a second high-temperature strengthening layer in order to improve the chipping resistance of the hard coating layer of the coated cermet tool. Layer, that is, excellent heat resistance due to the inclusion of the Zr component, relatively high high-temperature strength due to the inclusion of the Ti component, and as schematically shown in FIG. 1A, Ti, Zr, carbon, Focus on a (Ti, Zr) CN layer having a crystal structure of NaCl-type face-centered cubic crystal in which constituent atoms of nitrogen and nitrogen are present (FIG. 1 (b) shows a state cut by the (011) plane) As a result of research,
(A) A (Ti, Zr) CN layer (hereinafter referred to as a conventional (Ti, Zr) CN layer) which is a second high-temperature strengthened layer (hereinafter referred to as a conventional high-temperature strengthened layer) constituting a hard coating layer of a conventional coated cermet tool For example, in a normal chemical vapor deposition apparatus,
Reaction gas composition: by _{volume%, TiCl 4: 1~5%,} ZrCl 4: 0.1~1%, CH 3 CN: 0.6~5%, N 2: 25~45%, H 2: remainder,
Reaction atmosphere temperature: 750-980 ° C.
Reaction atmosphere pressure: 2.7 to 13.5 kPa,
It is formed by vapor deposition under the conditions (called normal conditions).
Reaction gas composition: by _{volume%, TiCl 4: 20~30%,} ZrCl 4: 0.5~4%, CH 3 CN: 5~10%, CH 4: 0.5~5%, N 2: 35~ 50%, H ₂ : remaining,
Reaction atmosphere temperature: 1000 to 1050 ° C.
Reaction atmosphere pressure: 6-20 kPa,
In other words, in the reaction gas composition, TiCl ₄ and CH ₃ CN are relatively high and CH ₄ gas is newly added to further increase the ambient temperature. When vapor deposition is performed under (reactive gas composition adjustment high temperature conditions), the (Ti, Zr) CN layer (hereinafter referred to as a modified (Ti, Zr) CN layer) formed under the resultant reaction gas composition adjustment high temperature conditions has a high temperature strength. Is further improved and has excellent mechanical impact resistance, the coated cermet tool in which the second layer of the hard coating layer is composed of the modified (Ti, Zr) CN layer is particularly suitable. The hard coating layer exhibits excellent chipping resistance even in high-speed intermittent cutting with severe mechanical impact, and exhibits excellent wear resistance over a long period of time.

(B) About the conventional (Ti, Zr) CN layer and the modified (Ti, Zr) CN layer of (a), which constitute the second layer of the hard coating layer of the conventional coated cermet tool,
Using a field emission scanning electron microscope, as illustrated in the schematic explanatory diagrams in FIGS. 2A and 2B, each crystal grain existing within the measurement range of the surface polished surface is irradiated with an electron beam, 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, with respect to the normal line of the surface polished surface (FIG. 2A shows (001) of the crystal planes. When the tilt angle of the surface is 0 degree and the tilt angle of the (011) plane is 45 degrees, the tilt angle of the (001) plane is 45 degrees and the tilt angle of the (011) plane is 0 degree. In this case, the crystal grains are composed of Ti, Zr, carbon, and nitrogen at lattice points as described above. It has a NaCl-type face-centered cubic crystal structure in which each atom exists, and based on the measured tilt angle obtained as a result. A 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 an interface between adjacent crystal grains is calculated, and the constituent atomic shared lattice points are calculated. A constitutive atom shared lattice point form in which there are N lattice points that do not share constituent atoms in between (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, and each ΣN + 1 is represented by ΣN + 1 When a constituent atomic shared lattice point distribution graph showing the distribution ratio occupying the whole (however, the upper limit is set to 28 in relation to the frequency) is created, the highest peak exists in Σ3 in any (Ti, Zr) CN layer However, the conventional (Ti, Zr) CN layer, as illustrated in FIG. 4, shows a relatively low constituent atom shared lattice point distribution graph in which the distribution ratio of Σ3 is 30% or less. Quality (Ti, Zr) CN layer , As illustrated in FIG. 3, the distribution ratio of Σ3 showed extremely high atom sharing lattice point distribution graph of 60-80%, the distribution ratio of the high Σ3 is, TiCl ₄ and _CH 3 CN constituting the reaction gas And the CH ₄ content and the atmospheric reaction temperature.

(C) The modified (Ti, Zr) CN layer is higher than the conventional (Ti, Zr) CN layer in addition to the high temperature strength and heat resistance of the (Ti, Zr) CN itself. Since it has high-temperature strength, the coated cermet tool formed by vapor deposition as a high-temperature reinforcing layer (hereinafter also referred to as a modified high-temperature reinforcing layer) constituting the second layer of the hard coating layer is the fourth high-temperature hard layer. Combined with the excellent high-temperature hardness and heat resistance of the Al ₂ O ₃ layer that constitutes the material, especially when intermittent cutting is performed under high-speed cutting conditions, and further, intermittent cutting is performed with high cutting depth and high feed, etc. Even when used in heavy cutting conditions, the chipping resistance of the hard coating layer is superior to that of the conventional coated cermet tool formed by vapor deposition of the conventional (Ti, Zr) CN layer. To come out.
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) First adhesion formed by chemical vapor deposition, either TiN layer or TiCN layer, or a laminate of both layers, and having an average layer thickness of 0.1 to 1 μm. The bonding layer (b) is formed by chemical vapor deposition as the second layer,
Composition formula: (Ti _1-X Zr _X ) CN (wherein X is 0.02 to 0.15 in atomic ratio),
A high-temperature strengthening layer comprising a (Ti, Zr) CN layer satisfying the following conditions and having an average layer thickness of 2.5 to 15 μm:
(C) as a third layer, a second adhesion bonding layer comprising either a TiCO layer and a TiCNO layer formed by chemical vapor deposition, or a laminate of both layers, and having an average layer thickness of 0.1 to 1 μm;
(D) As the fourth layer, a high-temperature hard layer comprising an Al ₂ O ₃ layer formed by chemical vapor deposition and 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,
The high-temperature strengthening layer, which is the second layer of the hard coating layers, is also formed by chemical vapor deposition, and has the composition formula: (Ti _1-X Zr _X ) CN (wherein X is 0.02 to 0.00 in terms of atomic ratio). 15), and further having an average layer thickness of 2.5 to 15 μm,
Using a field emission scanning electron microscope, each crystal grain existing within the measurement range of the surface polished surface is irradiated with an electron beam, and the crystal plane of the crystal grain is normal to the surface polished surface ( The inclination angle formed by the normal lines of the (001) plane and the (011) plane is measured. In this case, the crystal grains are NaCl-type face-centered cubes each having a constituent atom composed of Ti, Zr, carbon, and nitrogen at lattice points. A lattice in which each of the constituent atoms shares one constituent atom between the crystal grains at the interface between adjacent crystal grains based on the measured tilt angle obtained as a result of the crystal structure The distribution of the points (constituent atom shared lattice points) is calculated, and there are N lattice points that do not share the constituent atoms between the constituent atom shared lattice points (N is an even number of 2 or more in the crystal structure of the NaCl type face centered cubic crystal). ΣN is the existing configuration of atomic atom lattice points. In the constituent atom sharing lattice distribution graph showing the distribution ratio of each ΣN + 1 in the entire ΣN + 1 (however, the upper limit value is 28 due to the frequency), the highest peak exists in Σ3, A modified high-temperature strengthened layer comprising a modified (Ti, Zr) CN layer showing a constituent atom shared lattice point distribution graph in which the distribution ratio of Σ3 to the entire ΣN + 1 is 60 to 80%;
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 constituent layers of the hard coating layer of the coated cermet tool of the present invention are numerically limited as described above will be described below.
(A) First adhesion bonding layer The TiN layer and the TiCN layer constituting the first adhesion bonding layer are firmly bonded to both the tool base and the modified (Ti, Zr) CN layer as the second layer, Therefore, although it has the effect | action which contributes to the tight bondability improvement with respect to the tool base | substrate of a hard coating layer, if the average layer thickness is less than 0.1 micrometer, desired outstanding close bondability cannot be ensured, but close contact bondability Can be sufficiently secured with an average layer thickness of 1 μm, the average layer thickness was determined to be 0.1 to 1 μm.

(B) Modified high-temperature strengthened layer The distribution ratio of Σ3 in the constituent atomic shared lattice distribution graph of the modified (Ti, Zr) CN layer constituting the modified high-temperature strengthened layer that is the second layer of the hard coating layer is as described above. As shown in FIG. _4, the TiCl ₄ and CH ₃ CN constituting the reaction gas, the content of CH ₄ and the atmospheric reaction temperature can be adjusted to 60 to 80%. In this case, the distribution ratio of Σ3 is 60%. If the ratio is less than 1, it is not possible to ensure the excellent high-temperature strength improvement effect that does not cause chipping in the hard coating layer in the high-speed intermittent cutting process. Therefore, the higher the distribution ratio of Σ3, the better, but the distribution ratio of Σ3 Since it is difficult to form a layer exceeding 80%, the distribution ratio of Σ3 is set to 60 to 80%. As described above, the modified (Ti, Zr) CN layer has a further superior high-temperature strength in addition to the high-temperature strength and heat resistance of (Ti, Zr) CN itself as described above. If the average layer thickness is less than 2.5 μm, the desired excellent high-temperature strength improvement effect cannot be sufficiently provided to the hard coating layer. On the other hand, if the average layer thickness exceeds 15 μm, the thermoplasticity causes uneven wear. Since deformation tends to occur and wear accelerates, the average layer thickness is set to 2.5 to 15 μm.
Further, as described above, the Zr component in the modified (Ti, Zr) CN layer has an effect of improving heat resistance and suppressing softening in a high-temperature atmosphere during cutting. If the value is an atomic ratio occupying the total amount of Ti and less than 0.02, the desired heat resistance improvement effect cannot be obtained. On the other hand, if the X value exceeds 0.15, the high temperature strength tends to decrease. Therefore, the X value indicating the content ratio of Zr was determined to be 0.02 to 0.15.

(C) Second adhesion bonding layer The TiCO layer and the TiCNO layer constituting the second adhesion bonding layer are either a modified (Ti, Zr) CN layer that is a _second layer or an Al ₂ O ₃ layer that is a high-temperature hard layer. In addition, it has an effect of improving the tight bondability of the hard coating layer to the tool substrate, and if the average layer thickness is less than 0.1 μm, the desired excellent close bondability is ensured. On the other hand, since the tight adhesion can be sufficiently secured with an average layer thickness of 1 μm, the average layer thickness was determined to be 0.1 to 1 μm.

(D) High-temperature hard layer The Al ₂ O ₃ layer constituting the high-temperature hard layer has excellent high-temperature hardness and heat resistance, and contributes to improving the wear resistance of the hard coating layer, but the average layer thickness is less than 1 μm. In this case, the hard coating layer cannot exhibit sufficient wear resistance. On the other hand, if the average layer thickness exceeds 15 μm, chipping is likely to occur. It was determined to be 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, but the average layer thickness in this case may be 0.1 to 1 μm, This is because 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 with an average layer thickness of up to 1 μm.

  The coated cermet tool of the present invention is a modified (Ti, Zr) CN layer (modified high-temperature strengthened layer) that is the second 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. However, it has excellent high-temperature strength and exhibits excellent chipping resistance, and thus exhibits excellent wear resistance over a long period of time without occurrence of chipping in the hard coating layer.

  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 defined in ISO · CNMG12041 were manufactured.

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 the sintering, the cutting edge portion was subjected to a honing process of R: 0.07 mm. Tool bases a to f made of TiCN-based cermet having a standard / CNMG12041 chip shape were formed.

Next, a normal chemical vapor deposition apparatus is used on the surfaces of the tool bases A to F and the tool bases a to f, and first, a first adhesive bonding layer made of either a TiN layer or a TiCN layer, or a laminate of both. Are formed under the conditions shown in Table 3 with the target layer thickness shown in Table 5, and then the modified (Ti, Zr) CN layer (modified high-temperature strengthened layer) is formed under the conditions shown in Table 4. Then, a second adhesion bonding layer composed of one or both of a TiCO layer and a TiCNO layer is formed under the conditions shown in Table 3, and the target layer thickness shown in Table 5 is formed. Then, the coated cermet tools 1 to 13 of the present invention are formed by vapor-depositing the Al ₂ O ₃ layer (high-temperature hard layer) with the target layer thickness shown in Table 5 under the same conditions as shown in Table 3. Each was manufactured.

For comparison purposes, as shown in Table 6, a conventional hard coating layer (Ti, Zr) in which the second layer of the hard coating layer is formed by vapor deposition under the conditions shown in Table 4 and with the target layer thicknesses shown in Table 6. Conventionally coated cermet tools 1 to 13 are manufactured by vapor-depositing a first adhesive bonding layer, a second adhesive bonding layer, and an Al ₂ O ₃ layer (high-temperature hard layer) under the same conditions except for the CN layer. did.

Subsequently, the modified (Ti, Zr) CN layer and the conventional (Ti, Zr) CN layer constituting the hard coating layer of the above-described coated cermet tool of the present invention and the conventional coated cermet tool are examined using a field emission scanning electron microscope. Each component atom shared lattice distribution graph was created.
That is, the constituent atomic shared lattice point distribution graph shows a mirror of a field emission scanning electron microscope in a state where the surfaces of the modified (Ti, Zr) CN layer and the conventional (Ti, Zr) CN layer are polished surfaces. An electron beam with an acceleration voltage of 15 kV at an incident angle of 70 degrees is applied to the polished surface with an irradiation current of 1 nA to each crystal grain existing within the measurement range of the surface polished surface. Using a backscatter diffraction image apparatus, a (001) plane and a (011) plane that are crystal planes of the crystal grains with respect to the normal line of the surface-polished surface in a 30 × 50 μm region at an interval of 0.1 μm / step. The inclination angle formed by the normal of the surface is measured, and based on the measurement inclination angle obtained as a result, each of the constituent atoms is one constituent atom between the crystal grains at the interface between adjacent crystal grains. Shared lattice points (constituent atom shared lattice points The constituent atomic shared lattice in which there are N lattice points that do not share constituent atoms between the constituent atomic shared lattice points (N is an even number of 2 or more in the crystal structure of the NaCl type face centered cubic crystal) When the point form is expressed as ΣN + 1, it is created by calculating the distribution ratio of each ΣN + 1 to the entire ΣN + 1 (however, the upper limit value is 28 due to the frequency).

  In the constituent atomic shared lattice distribution graphs of the various modified (Ti, Zr) CN layers and conventional (Ti, Zr) CN layers obtained as a result, the entire ΣN + 1 (N is all even numbers in the range of 2 to 28). Table 7 shows the distribution ratio of Σ3.

In the above-mentioned various constituent atomic share lattice point distribution graphs, as shown in Table 7, all of the modified (Ti, Zr) CN layers of the coated cermet tool of the present invention have a distribution ratio of 60 to 80% of Σ3. In contrast to a certain constituent atomic shared lattice distribution graph, the conventional (Ti, Zr) CN layer of the conventional coated cermet tool shows a constituent atomic shared lattice distribution graph in which the distribution ratio of Σ3 is 30% or less. It was a thing.
FIG. 3 is a graph showing the distribution of constituent atomic lattice points of the modified (Ti, Zr) CN layer of the coated cermet tool 1 of the present invention, and FIG. 4 is a graph of the conventional (Ti, Zr) CN layer of the conventional coated cermet tool 1. The constituent atom shared lattice point distribution graphs are respectively shown.

  Further, for the above-described coated cermet tools 1 to 13 and the conventional coated cermet tools 1 to 13, the constituent layers of the hard coating layer were observed using an electron beam microanalyzer (EPMA) and an Auger spectroscopic analysis device (layer When the longitudinal section was observed), it was confirmed that both the former and the latter had substantially the same composition as the target composition. Moreover, when the thickness of the constituent layer of the hard coating layer of these coated cermet tools was measured using a scanning electron microscope (same longitudinal section measurement), the average layer thickness (substantially the same as the target layer thickness) The 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 / SS330 lengthwise equidistant 4 round bars with flutes,
Cutting speed: 440 m / min,
Incision: 1.5mm,
Feed: 0.25mm / rev,
Cutting time: 10 minutes,
Dry high-speed intermittent cutting test (normal cutting speed is 220 m / min) of mild steel under the above conditions (cutting condition A),
Work material: JIS / SUS303 lengthwise equidistant four round grooved round bars,
Cutting speed: 420 m / min,
Cutting depth: 1.3 mm,
Feed: 0.20mm / rev,
Cutting time: 10 minutes,
Dry high-speed intermittent cutting test of stainless steel under the above conditions (cutting condition B) (normal cutting speed is 200 m / min),
Work material: JIS / S10C lengthwise equidistant round bars with 4 vertical grooves,
Cutting speed: 420 m / min,
Cutting depth: 2.0 mm
Feed: 0.28mm / rev,
Cutting time: 10 minutes,
The dry high-speed intermittent cutting test (normal cutting speed is 220 m / min) of carbon steel 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, all of the coated cermet tools 1 to 13 of the present invention are constituent atomic shared lattice point distribution graphs in which the second layer configuration of the hard coating layer is 60 to 80% of Σ3 distribution ratio. The modified (Ti, Zr) CN layer has excellent high-temperature strength even in high-speed intermittent cutting of various steels, which are composed of the modified (Ti, Zr) CN layer shown and have extremely high mechanical impact. Since it exhibits chipping resistance, the occurrence of chipping in the hard coating layer is remarkably suppressed and excellent wear resistance is exhibited, whereas the second layer of the hard coating layer has a Σ3 distribution ratio of 30% or less. In the conventional coated cermet tools 1 to 13 composed of the conventional (Ti, Zr) CN layer showing the constituent atomic shared lattice point distribution graph, the mechanical impact resistance of the hard coating layer is insufficient with high-speed intermittent cutting. To be hard It is clear that chipping occurs in the covering layer and the service life is reached in a relatively short time.

  As described above, the coated cermet tool of the present invention has a hard coating layer 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 that requires particularly high high-temperature strength. Because it shows excellent chipping resistance and exhibits excellent cutting performance over a long period of time, it can sufficiently satisfy the high performance of cutting equipment, labor saving and energy saving of cutting work, and further cost reduction. Is.

It is a schematic diagram which shows the crystal structure of the NaCl type face centered cubic crystal which the (Ti, Zr) CN layer which comprises the 2nd layer of a hard coating layer has. It is a schematic explanatory drawing which shows the measurement aspect of the inclination angle of the (001) plane of a crystal grain and the (011) plane in the (Ti, Zr) CN layer which comprises the 2nd layer of a hard coating layer. 4 is a constituent atomic shared lattice point distribution graph of a modified (Ti, Zr) CN layer constituting the second layer of the hard coating layer of the coated cermet tool 1 of the present invention. 4 is a constituent atomic shared lattice point distribution graph of a conventional (Ti, Zr) CN layer constituting the second layer of the hard coating layer of the conventional coated cermet tool 1.

Claims (1)

On the surface of the tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) As the first layer, a first adhesion having an average layer thickness of 0.1 to 1 μm, which is composed of any one of a titanium nitride layer and a titanium carbonitride layer formed by chemical vapor deposition, or a laminate of both layers. Bonding layer,
(B) The second layer is formed by chemical vapor deposition,
Composition formula: (Ti _1-X Zr _X ) CN (wherein X is 0.02 to 0.15 in atomic ratio),
A high-temperature strengthened layer comprising a composite carbonitride layer of Ti and Zr satisfying the following conditions and having an average layer thickness of 2.5 to 15 μm
(C) As the third layer, the first layer is composed of either a titanium carbonate layer formed by chemical vapor deposition or a titanium carbonitride oxide layer, or a laminate of both layers, and has an average layer thickness of 0.1 to 1 μm. 2 adhesive bonding layers,
(D) As the fourth layer, a high-temperature hard layer comprising an aluminum oxide layer formed by chemical vapor deposition and 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,
The high-temperature strengthening layer, which is the second layer of the hard coating layers, is also formed by chemical vapor deposition, and has the composition formula: (Ti _1-X Zr _X ) CN (wherein X is 0.02 to 0.00 in terms of atomic ratio). 15), and further having an average layer thickness of 2.5 to 15 μm,
Using a field emission scanning electron microscope, each crystal grain existing within the measurement range of the surface polished surface is irradiated with an electron beam, and the crystal plane of the crystal grain is normal to the surface polished surface ( The inclination angle formed by the normal lines of the (001) plane and the (011) plane is measured. In this case, the crystal grains are NaCl-type face-centered cubes each having a constituent atom composed of Ti, Zr, carbon, and nitrogen at lattice points. A lattice in which each of the constituent atoms shares one constituent atom between the crystal grains at the interface between adjacent crystal grains based on the measured tilt angle obtained as a result of the crystal structure The distribution of the points (constituent atom shared lattice points) is calculated, and there are N lattice points that do not share the constituent atoms between the constituent atom shared lattice points (N is an even number of 2 or more in the crystal structure of the NaCl type face centered cubic crystal). The existing constituent atomic shared lattice point form is ΣN 1 in the constituent atom sharing lattice distribution graph showing the distribution ratio of each ΣN + 1 in the entire ΣN + 1 (however, the upper limit is 28 due to the frequency), and Σ3 has the highest peak, and A modified high-temperature strengthened layer composed of a composite carbonitride layer of Ti and Zr showing a constituent atom shared lattice point distribution graph in which the distribution ratio of Σ3 to the entire ΣN + 1 is 60 to 80%,
A surface-coated cermet cutting tool that exhibits excellent chipping resistance with a hard coating layer in high-speed intermittent cutting characterized by comprising

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