JP2006334756A - Surface coated cermet cutting tool whose hard coating layer exhibits excellent chipping resistance in high-speed and deep cutting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cermet cutting tool whose hard coating layer exhibits excellent chipping resistance in high-speed and deep cutting. <P>SOLUTION: This coated cermet cutting tool is constructed by forming the hard coating layer on the surface of a tool base by vapor deposition. The hard coating layer is composed of (a) a lower layer, which is a Ti compound layer having the total average layer thickness ranging from 3 to 20 μm and (b) an upper layer, which is composed of a first unit layer and a second unit layer and has an alternately stacking structure having total average layer thickness ranging from 6 to 30 μm. In the coated cermet tool, the first unit layer is formed of a deposition α-type Al<SB>2</SB>O<SB>3</SB>layer, and the second unit layer is formed of a Ti compound layer. The alternately stacking structure is constructed by alternately stacking the first unit layer and the second unit layer respectively having the average layer thickness ranging from 1.5 to 5 μm in at least four layers or more. The first unit layer is constructed of the deposition α-type Al<SB>2</SB>O<SB>3</SB>layer showing a specified inclination angle frequency distribution graph. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

In the present invention, particularly in a state in which an aluminum oxide layer (hereinafter referred to as an Al ₂ O ₃ layer) that is a constituent layer of a hard coating layer is thickened, various kinds of cutting work such as steel and cast iron can be performed at high speed. Even under heavy cutting conditions such as high cutting and high feed with high mechanical impact, the hard coating layer exhibits excellent chipping resistance, and therefore, no chipping (small chipping) occurs, and long-term The present invention relates to a surface-coated cermet cutting tool (hereinafter referred to as a coated cermet tool) that exhibits excellent wear resistance.

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) The lower layer is a Ti carbide (hereinafter referred to as TiC) layer, a nitride (hereinafter also referred to as TiN) layer, a carbonitride (hereinafter referred to as TiCN) layer, a carbon oxide (hereinafter referred to as TiCO). A Ti compound layer consisting of one or two or more layers of carbonitride oxide (hereinafter referred to as TiCNO) layers and having an overall average layer thickness of 3 to 20 μm,
(B) An aluminum oxide layer having an average layer thickness of 1 to 12 μm and having an α-type crystal structure in a state of chemical vapor deposition (hereinafter referred to as vapor deposition α-type Al) ₂ O ₃ layer)
There is known a coated cermet tool formed by vapor-depositing a hard coating layer composed of (a) and (b) above, and this coated cermet tool can be used for continuous cutting and intermittent cutting of various steels and cast irons, for example. It is well known to be used.
In the above coated cermet tool, the upper layer of (b) is not formed by the vapor-deposited α-type Al ₂ O ₃ layer alone, but the vapor-deposited α-type Al ₂ O ₃ layer and Ti compound layer (for example, Ti Nitride (hereinafter referred to as TiN) layer, carbide (hereinafter referred to as TiC) layer, carbonitride (hereinafter referred to as TiCN) layer, carbonitride oxide (hereinafter referred to as TiCNO) layer, nitride oxide ( In the following, a device for improving the adhesion, hardness, and wear resistance of the hard coating layer has also been made by forming an alternate laminated structure of a layer of TiNO) and a carbonate (hereinafter referred to as TiCO) layer. .

Since the vapor-deposited α-type Al ₂ O ₃ layer and the Ti compound layer both have predetermined hardness and strength, the vapor-deposited α-type Al ₂ O ₃ layer and the Ti compound layer are provided with an upper layer composed of an alternating laminated structure. It is well known that these conventional coated cermet tools formed by vapor-depositing a hard coating layer are used for continuous cutting and intermittent cutting of, for example, various types of steel and cast iron.

In general, the Ti compound layer and vapor-deposited α-type Al ₂ O ₃ layer constituting the hard coating layer of the above-mentioned coated cermet tool have a granular crystal structure, and further, the TiN, TiCO, TiCNO constituting the Ti compound layer It is also known that each layer is formed by chemical vapor deposition with a normal chemical vapor deposition apparatus by selecting a reaction gas and reaction conditions according to the type of Ti compound to be formed.
Japanese Unexamined Patent Publication No. 6-31503 Japanese Patent Laid-Open No. 6-8010 JP-A-1-252306 Japanese National Publication No. 4-504085

In recent years, the performance of cutting machines has been remarkably improved. On the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting work. Accordingly, the vapor deposited α-type Al ₂ O ₃ layer has a maximum thickness of 20 μm. Although it is necessary to increase the thickness of the film and the cutting process is further accelerated, there is a tendency to strongly demand cutting work under heavy cutting conditions such as high cutting and high feed, but in the conventional coated cermet tool described above, There is no problem when this is used for continuous cutting and interrupted cutting under normal conditions such as steel and cast iron, but especially when this is used under high speed heavy cutting conditions, vapor deposition that constitutes a hard coating layer. Since the high-temperature hardness and high-temperature strength of the α-type Al ₂ O ₃ layer are insufficient, wear progresses rapidly and chipping easily occurs, and the thick film of the vapor-deposited α-type Al ₂ O ₃ layer Chipping is one step higher Since the more likely to occur, at present, leading to a relatively short time service life.

In view of the above, the inventors of the present invention have an upper layer of an alternately laminated structure in which the upper layer of the hard coating layer is formed by alternately laminating four or more of vapor-deposited α-type Al ₂ O ₃ layers and Ti compound layers. Paying attention to the formed conventional coated cermet tool, as a result of conducting research to improve the chipping resistance of the vapor-deposited α-type Al ₂ O ₃ layer, particularly the upper layer of the hard coating layer,
(A) The vapor-deposited α-type Al ₂ O ₃ layer in the hard coating layer of the conventional coated cermet tool is generally a normal chemical vapor deposition apparatus.
Reaction gas composition: by _{volume%, AlCl 3: 1~5%,} CO 2: 3~7%, HCl: 0.3~3%, H 2 S: 0.02~0.4%, H 2: remainder ,
Reaction atmosphere temperature: 950-1100 ° C.
Reaction atmosphere pressure: 6-13 kPa,
The evaporated α-type Al ₂ O ₃ layer (hereinafter referred to as a vapor-deposited α-type Al ₂ O ₃ standard layer) formed under the normal conditions is subjected to a field emission scanning electron microscope. 1 (a) and 1 (b), the crystal grains having a hexagonal crystal lattice existing within the measurement range of the surface polished surface are irradiated with an electron beam, and the surface The inclination angle formed by the normal line of the (0001) plane, which is the crystal plane of the crystal grain, is measured with respect to the normal line of the polished surface, and the measurement inclination is in the range of 0 to 45 degrees of the measurement inclination angle. When the angle is divided for each pitch of 0.25 degrees and a tilt angle number distribution graph is created by summing up the frequencies existing in each section, as shown in FIG. 3, the measured tilt of the (0001) plane An inclination angle number distribution graph that is unbiased within an angle distribution range of 0 to 45 degrees is shown. A.

(B) On the other hand, the vapor-deposited α-type Al ₂ O ₃ layer was similarly used with a normal chemical vapor deposition device,

Reaction gas composition: volume%, AlCl ₃ : 6 to 10%, CO ₂ : 0.1 to 1%, HCl: 0.3 to 3%, H ₂ S: 0.5 to 1%, Ar: 10 to 10% 35%, H ₂ : remaining,
Reaction atmosphere temperature: 1000 to 1050 ° C.
Reaction atmosphere pressure: 5 to 8 kPa,
If the reaction gas composition is adjusted to the reaction gas composition different from the reaction gas composition of the above normal conditions (the temperature and pressure of the reaction atmosphere are the same as the above normal conditions), this result is obtained. The formed deposited α-type Al ₂ O ₃ layer (hereinafter referred to as a deposited α-type Al ₂ O ₃ modified layer) is shown in FIGS. 1A and 1B using a field emission scanning electron microscope. As described above, each crystal grain having a hexagonal crystal lattice existing within the measurement range of the surface polished surface is irradiated with an electron beam, and is a crystal plane of the crystal grain with respect to the normal line of the surface polished surface (0001 ) Measure the tilt angle formed by the normal of the surface, and 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 exist in each section In the case of the inclination angle frequency distribution graph, which is a summary of the frequencies to be As exemplified above, a sharp maximum peak appears at a specific position of the tilt angle section, and according to the test results, when the reaction atmosphere pressure in the chemical vapor deposition apparatus is changed within the range of 5 to 8 kPa as described above, The position at which the sharpest peak appears changes within the range of 0 to 10 degrees of the inclination angle section, and the total of the frequencies existing within the range of 0 to 10 degrees is 45 of the entire degrees in the inclination angle frequency distribution graph. The modified layer in which the highest peak of the inclination angle section appears in the range of 0 to 10 degrees in the inclination angle number distribution graph of the resulting inclination angle distribution graph is the above-mentioned vapor deposition α type formed under the normal conditions Compared to the Al ₂ O ₃ standard layer, it has a relatively good high temperature strength, although it has a decrease in high temperature hardness.

(C) In an upper layer of a hard coating layer of a conventional coated cermet tool, that is, an upper layer having an alternately laminated structure in which four or more vapor-deposited α-type Al ₂ O ₃ standard layers and Ti compound layers are alternately laminated, Type Al ₂ O ₃ layer is replaced with the above-mentioned vapor deposition α-type Al ₂ O ₃ standard layer formed under normal conditions in (a), and vapor deposition α-type Al ₂ O ₃ modification under reaction gas composition adjustment conditions in (b) above Then, the deposited α-type Al ₂ O ₃ modified layer and the Ti compound layer alternately laminated thereon are made into an alternately laminated structure of four or more layers with an average layer thickness of 1.5 to 5 μm. And the covering cermet tool which constitutes the upper layer which made the total average layer thickness 6-30 micrometers as the upper layer of the hard covering layer whose lower layer consists of a Ti compound layer, the upper layer which has the above-mentioned alternate lamination structure, It has excellent high temperature hardness and high strength along with excellent adhesion From becoming manner, especially in a state of being thickened in 30μm in maximum layer thickness, high speed even if the cutting heavy cutting conditions, alternately laminated with the vapor deposition α-type Al ₂ O ₃ standard layer and the Ti compound layer Compared to the conventional coated cermet tool, the hard coating layer exhibits excellent wear resistance over a long period of time without the occurrence of chipping.
The research results shown in (a) to (c) above were obtained.

This invention was made based on the above research results, and on the surface of the tool base,
(A) a Ti compound layer in which the lower layer is composed of one or more of a TiC layer, a TiN layer, a TiCN layer, a TiCO layer, and a TiCNO layer, and has an overall average layer thickness of 3 to 20 μm,

(B) a first unit layer and a second unit layer, wherein the upper layer has an alternately laminated structure of the first unit layer and the second unit layer, and has an overall average layer thickness of 6 to 30 μm;
In the surface-coated cermet cutting tool formed by vapor-depositing the hard coating layer composed of (a) and (b) above,
The first unit layer is composed of an α-type aluminum oxide layer having an α-type crystal structure in the state of chemical vapor deposition, and the second unit layer is composed of a Ti carbide layer, a nitride layer, and a carbonitride layer. The Ti compound layer is composed of one or more of the carbonate layer and the carbonitride oxide layer, and the first unit layer and the second unit layer have an average layer thickness of 1.5 to 5 μm, respectively. And the alternate stacked structure including the first unit layer and the second unit layer is configured by alternately stacking at least four or more of the first unit layer and the second unit layer. Using an emission scanning electron microscope, each crystal grain having a hexagonal crystal lattice existing within the measurement range of the surface polished surface of the tool base is irradiated with an electron beam, and the normal of the surface polished surface is The inclination formed by the normal of the (0001) plane that is the crystal plane of the crystal grain Inclination obtained by measuring the angle and dividing the measurement inclination angle within the range of 0 to 45 degrees of the measurement inclination angles for each pitch of 0.25 degrees and totaling the frequencies existing in each division When expressed in the angle distribution graph,
The first unit layer has the highest peak in the inclination angle section within the range of 0 to 10 degrees, and the total of the frequencies existing in the range of 0 to 10 degrees is the entire frequency in the inclination angle number distribution graph. Showing an inclination angle number distribution graph occupying a ratio of 45 to 65% of

The hard coating layer characterized by the above is characterized by a surface-coated cermet cutting tool that exhibits excellent chipping resistance in high-speed heavy cutting.

The reason why the numerical values of the constituent layers of the hard coating layer of the coated cermet tool of the present invention are limited as described above will be described below.
(A) Ti compound layer (lower layer)
The Ti compound layer basically exists as the first unit layer and the second unit lower layer constituting the upper layer of the alternately laminated structure, and the hard coating layer has the high temperature strength due to its excellent high temperature strength. In addition to the above, the tool base and the first unit layer and the second unit layer constituting the upper layer are firmly adhered to each other, thereby contributing to the improvement of the adhesion of the hard coating layer to the tool base. If the average layer thickness is less than 3 μm, the above-mentioned effect cannot be fully exerted. On the other hand, if the average layer thickness exceeds 20 μm, thermoplastic deformation is likely to occur particularly in high-speed cutting with high heat generation. Since this causes uneven wear, the average layer thickness was determined to be 3 to 20 μm.

(B) First and second unit layers (upper layer)
As described above, the highest peak position of the measured inclination angle in the inclination angle number distribution graph of the first unit layer (deposited α-type Al ₂ O ₃ modified layer) represents the reaction atmosphere pressure in the chemical vapor deposition apparatus as described above. When it is changed within the range of 8 kPa, it changes within the range of 0 to 10 degrees of the inclination angle section, and the total of the frequencies existing within the range of 0 to 10 degrees is the total frequency in the inclination angle frequency distribution graph. An inclination angle number distribution graph occupying a ratio of 45 to 65% is shown (in this case, even if the reaction atmosphere pressure is adjusted, a frequency ratio of 65% or more cannot be occupied). The maximum peak position of the measured inclination angle is out of the range of 0 to 10 degrees regardless of whether the reaction atmosphere pressure is out of the range or low, and the corresponding inclination is angle The ratio of the frequencies existing in the range of 0 to 10 degrees in the number distribution graph is also less than 45% of the entire frequencies, and the desired excellent high-temperature strength cannot be ensured.
In addition, the upper layer has sufficient characteristics of the first unit layer (deposited α-type Al ₂ O ₃ modified layer) and the second unit layer (alternately laminated Ti compound layers), that is, high temperature strength and high temperature hardness. In addition, the first unit layer (deposited α-type Al ₂ O ₃ modified layer) and the second unit layer (alternately laminated Ti compound layers) are alternately laminated over the entire layer thickness. In order to ensure the adhesion of the structure, it is necessary to make the average layer thickness of each unit layer 1.5 to 5 μm to form an alternating laminated structure of four or more layers, and therefore the average layer thickness is within the above range. If the number of alternating layers is less than 4 or less, at least one of the above characteristics is deteriorated, and the desired excellent high temperature strength, high temperature hardness and adhesion are balanced. Cannot be well equipped.
Furthermore, if the average layer thickness of the entire upper layer is less than 6 μm, the excellent characteristics of this cannot be fully exerted over a long period of time, while if the average layer thickness exceeds 30 μm, Since chipping (slight chipping) is likely to occur in the blade portion, the overall average layer thickness was determined to be 6 to 30 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 the outermost surface layer of the hard coating layer as necessary, but the average layer thickness in this case is It may be 0.1 to 1 μm, and if it 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 of the present invention is a state in which the upper layer of the hard coating layer is made thick, and various steels and cast irons are cut at a high speed with high mechanical impact and high cutting. The first unit layer (deposited α-type Al ₂ O ₃ modified layer) has excellent high-temperature strength and a predetermined high-temperature hardness, and the second unit layer (alternately laminated) (Ti compound layer) ensures the adhesion of the alternating layered structure of the upper layer, so that the hard coating layer has excellent wear resistance without occurrence of chipping, and the service life can be further extended. Is.

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

As raw material powders, WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, and Co powder each having an average particle diameter of 1 to 3 μm are prepared. The raw material powder is blended in the blending composition shown in Table 1, added with wax, ball mill mixed in acetone for 24 hours, dried under reduced pressure, and press-molded into a green compact of a predetermined shape at a pressure of 98 MPa. The green compact is vacuum-sintered in a vacuum of 5 Pa at a predetermined temperature within a range of 1370 to 1470 ° C. for 1 hour. After sintering, the cutting edge is subjected to a honing process of R: 0.07 mm. Thus, tool bases A to F made of a WC-based cemented carbide having a throwaway tip shape specified in ISO · CNMG120408 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.

Then, each of these tool bases A to F and tool bases a to f is charged into a normal chemical vapor deposition apparatus,
(A) First, Table 3 (l-TiCN in Table 3 indicates the conditions for forming a TiCN layer having a vertically elongated crystal structure described in JP-A-6-8010, and the other conditions are ordinary granularity. Under the conditions shown in Table 5 and 6), the Ti compound layer having the target layer thickness shown in Tables 5 and 6 is deposited as a lower layer of the hard coating layer.
(B) Next, on the conditions shown in Table 4, the vapor-deposited α-type Al ₂ O ₃ modified layer (a ) To (j) are formed by vapor deposition,
(C) Further, Ti compound layers (1) to (8), which are the second unit layers, are vapor-deposited under the conditions shown in Table 3 with the combinations shown in Tables 5 and 6, the target layer thickness, and the number of alternating layers. The coated cermet tools 1 to 13 of the present invention were produced.

For the purpose of comparison, the vapor deposition α-type Al ₂ O ₃ layer, which is the upper layer of the hard coating layer, is used as the formation condition of the vapor deposition α-type Al ₂ O ₃ standard layers (1) to (8) shown in Table 4 ( As described above, the formation conditions of the standard layers (1) to (8) are the same as the formation conditions of the vapor deposition α-type Al ₂ O ₃ layer), and the combinations and target layer thicknesses shown in Tables 7 and 8 are used. Except for forming, conventionally coated cermet tools 1 to 13 were produced under the same conditions as those of the present invention coated cermet tools 1 to 13, respectively.

Next, the first and second unit layers constituting the upper layer of the hard coating layer of the above-described coated cermet tool 1-13 of the present invention, and the vapor deposition α-type Al ₂ O constituting the upper layer of the conventional coated cermet tool 1-13. _{For each of the three} standard layers, a tilt angle number distribution graph was prepared using a field emission scanning electron microscope.
That is, the gradient angle distribution graph shows the field emission type in the state where each surface is a polished surface for the first unit layer and the second unit layer of the upper layer of the coated cermet tools 1 to 13 of the present invention. A hexagonal crystal that is set in a scanning electron microscope column and exists in the measurement range of each surface polished surface with an electron beam with an acceleration voltage of 15 kV at an incident angle of 70 degrees and an irradiation current of 1 nA on the polished surface. Each crystal grain having a crystal lattice is irradiated, and an electron backscatter diffraction image apparatus is used, and a region of 30 × 50 μm is spaced at a spacing of 0.1 μm / step with respect to the normal of the polished surface. The inclination angle formed by the normal line of the (0001) plane which is the crystal plane is measured, and based on this measurement result, the measurement inclination angle within the range of 0 to 45 degrees of the measurement inclination angle is 0.25 degrees. If divided into different pitches, It was created by aggregating the frequencies present in each segment.
In addition, the vapor-deposited α-type Al ₂ O ₃ standard layer (corresponding to any one of the standard layers (1) to (8) as described above) of the conventional coated cermet tools 1 to 13 has the same surface polished surface. Observed and created a tilt angle number distribution graph under the same conditions.

In the gradient angle distribution graphs of the various deposited α-type Al ₂ O ₃ layers obtained as a result, as shown in Tables 5 to 8, the first unit constituting the upper layer of the coated cermet tool 1 to 13 of the present invention. The layer (deposited α-type Al ₂ O ₃ modified layer) is an inclination angle number distribution graph in which the distribution of the measured inclination angle of the (0001) plane shows the highest peak in the inclination angle section within the range of 0 to 10 degrees, respectively. On the other hand, the deposited α-type Al ₂ O ₃ standard layer of the conventional coated cermet tools 1 to 13 is unbiased and has the highest peak within the range of the measured inclination angle of the (0001) plane in the range of 0 to 45 degrees. It was a graph showing the distribution of the number of tilt angles in which there is no.
Tables 5 to 8 show the inclination angles of all the inclination angles existing in the inclination angle sections in the range of 0 to 10 degrees in the inclination angle number distribution graphs of the various deposited α-type Al ₂ O ₃ layers. The percentage of the entire number distribution graph is shown.
2 is an inclination angle number distribution graph of the first unit layer (deposited α-type Al ₂ O ₃ modified layer) constituting the upper layer of the coated cermet tool 1 of the present invention, and FIG. the inclination angle frequency distribution graph showing the tilt angle sections of 0 to 45 degrees of deposition α-type Al ₂ O ₃ standard layer constituting the upper layer.

  Moreover, when the thickness of the constituent layer of the hard coating layer of the present invention coated cermet tools 1 to 13 and the conventional coated cermet tools 1 to 13 obtained as a result was measured using a scanning electron microscope (longitudinal section measurement) , Each showed an average layer thickness (average value of 5-point measurement) substantially the same as the target layer thickness.

Next, for the various coated cermet tools of the present invention coated cermet tool 1-13 and the conventional coated cermet tool 1-13, all of them are screwed with a fixing jig to the tip of the tool steel tool,
Work material: S58C
Cutting speed: 400 m / min. ,
Cutting depth: 1.0 mm,
Feed: 0.4 mm / rev. ,
Cutting time: 7 minutes,
Dry continuous high-speed high-feed cutting test of carbon steel under the following conditions (referred to as cutting condition A) (normal cutting speed and feed are 200 m / min. And 0.20 mm / rev.),
Work material: SCM440,
Cutting speed: 400 m / min. ,
Cutting depth: 3.0 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 6 minutes,
In a dry interrupted high-speed high-cutting test of the alloy steel under the conditions (cutting condition B) (normal cutting speed and cutting is 200 m / min. And 1.5 mm),
Work material: FC300
Cutting speed: 500 m / min. ,
Cutting depth: 3.5 mm,
Feed: 0.45 mm / rev. ,
Cutting time: 5 minutes,
The dry continuous high-speed, high-cut cutting test (normal cutting speed and cutting is 200 m / min. And 1.5 mm) of cast iron under the above conditions (referred to as cutting condition C). The width was measured. The measurement results are shown in Table 9.

From the results shown in Tables 5 to 9, in the coated cermet tools 1 to 13 of the present invention, the upper layer of the hard coating layer has an alternately laminated structure of first and second unit layers, and the first unit layer The (deposited α-type Al ₂ O ₃ modified layer) showed the highest peak in the inclination angle section in the range of 0 to 10 degrees in the inclination angle number distribution graph of the (0001) plane, and as a result, it was relatively excellent. Since the second unit layer (Ti compound layer) has high-temperature strength and the adhesiveness of the upper layer of the alternately laminated structure is secured, in the state where the thickness of the upper layer is increased, Even when cast iron is machined at high speed and under high-speed heavy cutting conditions with high mechanical impact, it exhibits excellent wear resistance without occurrence of chipping. The deposited α-type Al ₂ O ₃ layer has a distribution of measured inclination angles on the (0001) plane within the range of 0 to 45 degrees. In the conventional coated cermet tools 1 to 13 composed of vapor-deposited α-type Al ₂ O ₃ standard layers showing an inclination angle number distribution graph that is unbiased and does not have the highest peak, all of the vapor-deposited α-type Al ₂ O ₃ layers It is clear that chipping occurs in the hard coating layer under high-speed heavy cutting conditions due to the lack of high-temperature strength, and the service life is reached in a relatively short time.

  As described above, the coated cermet tool of the present invention is excellent in that there is no chipping in the hard coating layer even in continuous cutting and intermittent cutting under normal conditions such as various steels and cast iron, especially in high-speed heavy cutting. High wear resistance and excellent cutting performance over a long period of time can be fully satisfied with the high performance of cutting equipment, labor saving and energy saving of cutting, and cost reduction It is.

Is a schematic explanatory view showing the measurement range of the inclination angle in the case of measuring the crystal grains (0001) plane of the first unit layer constituting the upper layer (deposited α-type Al ₂ O ₃ modified layer) of the hard coating layer . The inclination angle frequency distribution graph of the present invention coated cermet tool 1 first unit layer constituting the upper layer of the hard coating layer of (deposited α-type Al ₂ O ₃ modified layer) (0001) plane. The inclination angle frequency distribution graph showing the tilt angle sections of 0 to 45 degrees of the conventional coated cermet tool 1 deposited α-type constituting the hard layer Al ₂ O ₃ standard layer (0001) plane.

Claims (1)

On the surface of the tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) The lower layer is composed of one or more of a Ti carbide layer, a nitride layer, a carbonitride layer, a carbonate layer, and a carbonitride layer, and has an overall average of 3 to 20 μm. A Ti compound layer having a layer thickness,
(B) a first unit layer and a second unit layer, wherein the upper layer has an alternately laminated structure of the first unit layer and the second unit layer, and has an overall average layer thickness of 6 to 30 μm;
In the surface-coated cermet cutting tool formed by vapor-depositing the hard coating layer composed of (a) and (b) above,
The first unit layer is composed of an α-type aluminum oxide layer having an α-type crystal structure in the state of chemical vapor deposition, and the second unit layer is composed of a Ti carbide layer, a nitride layer, and a carbonitride layer. And a Ti compound layer composed of one or more of a carbon oxide layer and a carbonitride oxide layer, and the first unit layer and the second unit layer each have an average layer thickness of 1.5 to 5 μm. And the alternate stacked structure including the first unit layer and the second unit layer is configured by alternately stacking at least four or more of the first unit layer and the second unit layer. Using an emission scanning electron microscope, each crystal grain having a hexagonal crystal lattice existing within the measurement range of the surface polished surface of the tool base is irradiated with an electron beam, and the normal of the surface polished surface is The inclination formed by the normal of the (0001) plane that is the crystal plane of the crystal grain Inclination obtained by measuring the angle and dividing the measurement inclination angle within the range of 0 to 45 degrees of the measurement inclination angles for each pitch of 0.25 degrees and counting the frequencies existing in each division When expressed in the angle distribution graph,
The first unit layer has the highest peak in the inclination angle section in the range of 0 to 10 degrees, and the total frequency existing in the range of 0 to 10 degrees is the entire frequency in the inclination angle number distribution graph. Showing an inclination angle number distribution graph occupying a ratio of 45 to 65% of

A surface-coated cermet cutting tool that features a hard coating layer that exhibits excellent chipping resistance in high-speed heavy cutting.

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