JP2006334754A - Surface coated cermet cutting tool with hard coated layer exhibiting excellent chipping resistance in high speed deep cutting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cermet cutting tool a hard coated layer of which exhibits excellent chipping resistance in high speed deep cutting. <P>SOLUTION: This coated cermet tool is constituted by vapor-depositing the hard covered layer (a) a lower part layer of which is constituted of a Ti compound layer having total average layer thickness of 3 to 20 μm and (b) an upper part layer of which is constituted of a deposited α type Al<SB>2</SB>O<SB>3</SB>layer having average layer thickness of 3.5 to 11 μm, the deposited α type Al<SB>2</SB>O<SB>3</SB>layer is made into a three layer laminated structure made of a first unit layer and a second unit layer respectively having average layer thickness of 1.5 to 5 μm and an intermediate layer interposed between the first unit layer and the second unit layer and it is constituted of the deposited α type Al<SB>2</SB>O<SB>3</SB>layer an inclination of which made by a normal of a surface (0001) which is a crystal surface of crystal grains shows an inclination frequency distribution graph by irradiating each of the crystal grains having a hexagonal crystal lattice existing in a measured range of a polishing surface in parallel with the tool base body surface with an electron beam by using a field emission type scanning electronic microscope. <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 general, the Ti compound layer and vapor-deposited α-type Al ₂ O ₃ layer constituting the hard coating layer of the above coated cermet tool have a granular crystal structure, and the TiCN layer constituting the Ti compound layer is For the purpose of improving its own strength, it is formed by chemical vapor deposition in a medium temperature range of 700 to 950 ° C using a mixed gas containing organic carbonitrides as a reaction gas in a normal chemical vapor deposition apparatus, and vertically grown. It is also known to have a crystal structure.
Japanese Unexamined Patent Publication No. 6-31503 Japanese Patent Laid-Open No. 6-8010

In recent years, the performance of cutting equipment has been remarkable. On the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting work. Further, cutting speed is further increased, and heavy cutting such as high cutting and high feed. Although there is a tendency that cutting under conditions is strongly demanded, in the above-mentioned conventional coated cermet tool, there is no problem when it is used for continuous cutting and intermittent cutting under normal conditions such as steel and cast iron. Especially when this is used under high-speed heavy cutting conditions, wear progresses rapidly because the high-temperature hardness and high-temperature strength of the vapor-deposited α-type Al ₂ O ₃ layer that constitutes the hard coating layer is insufficient. In addition, chipping is likely to occur, and further chipping is more likely to occur due to the thickening of the deposited α-type Al ₂ O ₃ layer, so that the service life is reached in a relatively short time.

In view of the above, the present inventors paid attention to a coated cermet tool in which the vapor-deposited α-type Al ₂ O ₃ layer constitutes the upper layer of the hard coating layer, and particularly the vapor-deposited α-type Al ₂ O 3. As a result of research to improve chipping resistance of _three layers,
(A) The vapor-deposited α-type Al ₂ O ₃ layer as a hard coating layer of the above-described conventional coated cermet tool is generally used in 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,
1 (a), (b) and FIG. 1 using the field emission scanning electron microscope for the deposited α-type Al ₂ O ₃ layer formed under the normal conditions. 2 (a) and (b), as schematically shown in the drawing, each crystal grain having a hexagonal crystal lattice existing within the measurement range of the polished surface parallel to the tool substrate surface is irradiated with an electron beam, 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. Of the measured inclination angles, 0 to 45 degrees and 45 to 90 degrees, respectively. As shown in FIGS. 5 and 6, when the measured inclination angle within the range is divided into pitches of 0.25 degrees, and an inclination angle number distribution graph is created by summing up the frequencies existing in each division. , (0001) plane measured tilt angle distribution is 0 to 45 degrees and 45 to 90 degrees An unbiased inclination angle number distribution graph within the range of.

(B) On the other hand, the α-type Al ₂ O ₃ layer was similarly used with a normal chemical vapor deposition apparatus,
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 deposited α-type Al ₂ O ₃ layer formed was similarly measured using a field emission scanning electron microscope, as shown in FIGS. 1 (a) and 1 (b), within the measurement range of a polished surface parallel to the tool substrate surface. Each of the crystal grains having a hexagonal crystal lattice existing in the substrate is irradiated with an electron beam, and the inclination angle formed by the normal line of the (0001) plane that is the crystal plane of the crystal grain is made relative to the normal line of the 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 shown in the distribution graph, as illustrated in FIG. A sharp maximum peak appears at a specific position in the oblique section. 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 sharp maximum peak appears. While the position changes within the range of 0 to 10 degrees of the inclination angle section, the total of the frequencies existing within the range of 0 to 10 degrees is a ratio of 45 to 65% of the total degrees in the inclination angle frequency distribution graph. The deposited α-type Al ₂ O ₃ layer in which the highest peak of the tilt angle section appears in the range of 0 to 10 degrees in the resulting tilt angle number distribution graph is the deposited α-type Al of the above-mentioned normal conditions. Compared to the ₂ O ₃ layer, it has relatively high temperature strength.

(C) Furthermore, the vapor-deposited α-type Al ₂ O ₃ layer was similarly used with 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: 750 to 900 ° C.
Reaction atmosphere pressure: 20-30 kPa,
2 formed under the relatively low temperature and high pressure conditions (reaction gas composition is the same as the above normal conditions), the deposited α-type Al ₂ O ₃ layer formed as a result is also shown in FIG. As shown in (a) and (b), each crystal grain having a hexagonal crystal lattice existing in the measurement range of the polishing surface parallel to the tool base surface is irradiated with an electron beam, 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, and the measurement inclination angle within the range of 45 to 90 degrees out of the measurement inclination angles is set to 0. .When divided into 25-degree pitches and represented by an inclination angle number distribution graph in which the frequencies existing in each area are aggregated, as shown in FIG. The highest peak appears and the test results show that When the atmospheric pressure is changed within the range of 20 to 30 kPa as described above, the position at which the sharpest peak appears changes within the range of 75 to 85 degrees of the inclination angle section, and the 75 to 85 degrees The sum of the frequencies existing in the range occupies a ratio of 45 to 65% of the entire frequency in the tilt angle frequency distribution graph, and the tilt angle falls within the range of 75 to 85 degrees in the resulting tilt angle frequency distribution graph. The vapor-deposited α-type Al ₂ O ₃ layer in which the highest peak of the section appears has a relatively high high-temperature hardness as compared with the vapor-deposited α-type Al ₂ O ₃ layer formed under normal conditions.

(D) The vapor deposition α-type Al ₂ O ₃ layer under the reaction gas composition adjustment conditions in (b) above is the first unit layer, and the vapor deposition α-type Al ₂ O ₃ layer under the low-temperature and high-pressure conditions in (c) above is the second unit layer. The vapor deposition α-type Al ₂ O ₃ layer under the normal conditions (a) is used as an intermediate layer, and the average thickness of each of the first unit layer and the second unit layer is set to 1.5 to 5 μm. The intermediate layer is interposed between the layer and the second unit layer to form a three-layer structure, and the deposited α-type Al ₂ O ₃ layer having an overall average layer thickness of 3.5 to 11 μm, and the lower layer is a Ti compound layer A coated cermet tool configured as an upper layer of a hard coating layer made of a material having excellent high-temperature hardness and high-temperature strength, particularly in a state in which the maximum layer thickness is increased to 11 μm, high-speed heavy cutting conditions Even when the cutting process is performed with the upper layer of the hard coating layer, the distribution of the measured inclination angle of the (0001) plane is the same. Hard coating layer compared to conventional coated cermet tools composed of vapor-deposited α-type Al ₂ O ₃ layers showing unbiased gradient angle distribution graphs in the range of 0 to 45 degrees and 45 to 90 degrees, respectively In addition, there is no need for chipping and the wear resistance is improved over a long period of time.
The research results shown in (a) to (d) 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 vapor-deposited α-type Al ₂ O ₃ layer whose upper layer has an average layer thickness of 3.5 to 11 μm;
In the coated cermet tool formed by vapor-depositing the hard coating layer composed of (a) and (b) above,

The aluminum oxide layer includes a first unit layer having an average layer thickness of 1.5 to 5 μm, a second unit layer having an average layer thickness of 1.5 to 5 μm, a first unit layer and a second unit layer, A crystal grain having a hexagonal crystal lattice existing in a measurement range of a polished surface parallel to the tool substrate surface using a field emission scanning electron microscope, and having a three-layer laminated structure including an intermediate layer interposed therebetween Individually irradiated with an electron beam, 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. The first unit layer is 0 to 45 degrees, the second unit layer is 45 to 90 degrees, and the intermediate layer is divided into 0 to 90 degrees for each inclination angle of 0.25 degrees. In addition, the inclination angle frequency distribution graph is formed by counting the frequencies existing in each category. When it appears in
(A) In the first unit layer, the highest peak exists in the inclination angle section in the range of 0 to 10 degrees, and the total of the frequencies existing in the range of 0 to 10 degrees is an inclination angle number distribution graph. The inclination angle frequency distribution graph which occupies the ratio of 45-65% of the whole frequency in is shown,
(B) In the second unit layer, the highest peak exists in the inclination angle section in the range of 75 to 85 degrees, and the total of the frequencies existing in the range of 75 to 85 degrees is an inclination angle number distribution graph. Showing an inclination angle frequency distribution graph occupying a proportion of 45 to 65% of the entire frequency in
(C) The intermediate layer has an inclination angle number distribution graph in which no peak exists over the entire measurement inclination angle section in the range of 0 to 90 degrees, and the distribution of the measurement inclination angle is unbiased.
The hard coating layer is characterized by a coated cermet 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) Lower layer (Ti compound layer)
The Ti compound layer basically exists as the lower layer of the vapor deposition α-type Al ₂ O ₃ layer of the upper layer, and in addition to allowing the hard coating layer to have high temperature strength due to its excellent high temperature strength, The tool substrate and the deposited α-type Al ₂ O ₃ layer are firmly adhered to each other, and thus have an effect of improving the adhesion of the hard coating layer to the tool substrate. However, when the average layer thickness is less than 3 μm, On the other hand, when the average layer thickness exceeds 20 μm, it becomes easy to cause thermoplastic deformation particularly in high-speed cutting with high heat generation, which causes uneven wear. The average layer thickness was determined to be 3-20 μm.

(B) Upper layer (first unit layer, second unit layer and intermediate layer)
As described above, the highest peak position of the measured inclination angle in each of the inclination angle number distribution graphs of the first and second unit layers is changed by changing the reaction atmosphere pressure in the chemical vapor deposition apparatus. Accordingly, when the reaction atmosphere pressure is 5 to 8 kpa in the first unit layer and 20 to 30 kPa in the second unit layer, the highest peak is 0 to 10 degrees in the first unit layer and the second unit layer. In this case, it appears in the inclination angle section in the range of 75 to 85 degrees, and the total of the frequencies existing in the range of 0 to 10 degrees and 75 to 85 degrees is the total of the degrees in the inclination angle number distribution graph in any case. An inclination angle number distribution graph occupying a ratio of 45 to 65% is shown. Therefore, even if the reaction atmosphere pressure deviates from the above range, However, the maximum peak position of the measured tilt angle is out of the range of 0 to 10 degrees and 75 to 85 degrees, respectively. In such a case, the first unit layer has the desired excellent high temperature. If it is the strength and further the second unit layer, it cannot have high temperature hardness.
In addition, in order to provide the upper layer with sufficient properties of the first and second unit layers, that is, high temperature strength and high temperature hardness, and uniformly throughout the entire layer thickness, the average of each of the unit layers It is necessary to make the layer thickness 1.5 to 5 μm. However, even when the average thickness of the first unit layer and the second unit layer is set in such a numerical range, the dominant crystal growth direction is obtained in each of the first unit layer and the second unit layer. Due to the difference, the interface (boundary region) between the first unit layer and the second unit layer is likely to be distorted due to the disorder of the growth direction, and the adhesion between the first unit layer and the second unit layer. May lead to a decline. Therefore, an internal layer having a strain relaxation action is interposed between the first unit layer and the second unit layer, thereby generating internal stress generated at the interface (boundary region) between the first unit layer and the second unit layer. Therefore, the internal strain generated in the first unit layer and the second unit layer or the internal strain generated in the entire upper layer is reduced.

As the intermediate layer, the first unit layer and the second unit layer should not be greatly different in crystal growth direction, so that the vapor deposition formed by the chemical vapor deposition under the normal conditions as described above. An α-type Al ₂ O ₃ layer can be used. By using a vapor-deposited α-type Al ₂ O ₃ layer formed by chemical vapor deposition under normal conditions as an intermediate layer, the internal stress generated between the first unit layer and the second unit layer is suppressed, and the first unit layer and the second unit are suppressed. The adhesion between the layers can be sufficiently secured, and the upper layer as a whole can form a high-quality, sound upper layer with extremely low internal stress and internal strain. An upper layer having both high-temperature hardness and a good balance can be obtained.
As the thickness of the intermediate layer, a minimum thickness that can exert a strain relaxation effect between the first unit layer and the second unit layer is required. On the other hand, if the thickness is too thick, the entire upper layer is required. Since the required high-temperature strength and high-temperature hardness that are required cannot be ensured in a well-balanced manner, the average layer thickness of the intermediate layer is preferably 0.5 to 1.0 μm.
Moreover, when the average layer thickness of the entire upper layer (deposited α-type Al ₂ O ₃ layer) composed of a three-layer structure of the first unit layer, the second unit layer, and the intermediate layer was less than 3.5 μm, this was excellent. The characteristics cannot be fully exhibited over a long period of time. On the other hand, if the average layer thickness exceeds 11 μm, chipping (small chipping) is likely to occur at the cutting edge, so the overall average The layer thickness was determined to be 3.5 to 11 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 capable of performing the above-described vapor deposition α-type Al even when cutting various steels and cast irons at high speeds and under heavy cutting conditions such as high cutting and high feed with high mechanical impact. ₂ O ₃ layer has low internal strain, excellent adhesion, and excellent high-temperature strength and high-temperature hardness. This makes it possible to further extend the life.

  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 4 and 5), the Ti compound layer having the target layer thickness shown in Tables 4 and 5 is deposited as the lower layer of the hard coating layer.
(B) Next, the reaction gas composition: volume%, AlCl ₃ : 7.4%, CO ₂ : 0.3%, HCl: 2.5%, H ₂ S: 0.7%, Ar: 30%, H ₂ : Remaining
Reaction atmosphere temperature: 1020 ° C.
Reaction atmosphere pressure: a predetermined pressure within a range of 5 to 8 kPa,
The first unit layer under the reaction gas composition adjustment conditions of
(C) Furthermore, the reaction gas composition: volume%, AlCl ₃ : 2.2%, CO ₂ : 5%, HCl: 2%, H ₂ S: 0.15%, H ₂ : the rest,
Reaction atmosphere temperature: 850 ° C.
Reaction atmosphere pressure: a predetermined pressure in the range of 20-30 kPa,
The second unit layer under low temperature and high pressure conditions of

(D) Reaction gas composition: volume%, AlCl ₃ : 1.5%, CO ₂ : 6.5%, HCl: 2.0%, H ₂ S: 0.25%, H ₂ : remaining,
Reaction atmosphere temperature: 1000 ° C.,
Reaction atmosphere pressure: 10 kPa,
Middle layer in normal conditions,
Were coated with the target layer thicknesses shown in Tables 4 and 5, respectively, to produce the coated cermet tools 1 to 13 of the present invention.

For the purpose of comparison, the formation of a vapor-deposited α-type Al ₂ O ₃ layer that constitutes the upper layer of the hard coating layer,
Reaction gas composition: volume%, AlCl ₃ : 2.2%, CO ₂ : 5%, HCl: 2%, H ₂ S: 0.15%, H ₂ : remaining,
Reaction atmosphere temperature: 1020 ° C.
Reaction atmosphere pressure: a predetermined pressure in the range of 6 to 13 kPa,
The conventional coated cermet tools 1 to 13 were produced under the same conditions as those of the present invention coated cermet tools 1 to 13 except that the target layer thicknesses shown in Tables 6 and 7 were used.

Next, the first and second unit layers and the intermediate layer 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 constituting the upper layer of the conventional coated cermet tool 1-13. With respect to the Al ₂ O ₃ layer, an inclination angle number distribution graph was prepared using a field emission scanning electron microscope.
That is, the above-mentioned inclination angle number distribution graph shows that the first unit layer, the second unit layer, and the intermediate layer of the upper layers of the above-described coated cermet tools 1 to 13 of the present invention are polished surfaces that are parallel to the tool base surface. In this state, each polishing surface is set in a lens barrel of a field emission scanning electron microscope, and an electron beam with an acceleration voltage of 15 kV at an incident angle of 70 degrees is applied to the polishing surface with an irradiation current of 1 nA. Irradiate each crystal grain having a hexagonal crystal lattice existing in the range, and use an electron backscatter diffraction image apparatus to make a region of 30 × 50 μm normal to the polished surface at an interval of 0.1 μm / step. On the other hand, the inclination angle formed by the normal line of the (0001) plane, which is the crystal plane of the crystal grain, is measured. Based on the measurement result, the first unit layer of the measurement inclination angle is 0-45. The second unit layer Was created by dividing the measured inclination angle within the range of 0 to 90 degrees for each of the above-mentioned intermediate layers into pitches of 0.25 degrees and counting the frequencies existing in each section. .
As for the conventional coated cermet tools 1 to 13 deposited α-type the Al ₂ O ₃ layer of, by observing the tool substrate parallel to the surface optionally polished surface under the same conditions to prepare a tilt angle frequency distribution graph in the same conditions .

In the inclination angle number distribution graphs of the various deposited α-type Al ₂ O ₃ layers obtained as a result, as shown in Tables 4 to 7, the first and the first layers constituting the upper layers of the coated cermet tools 1 to 13 of the present invention are shown. Each of the second unit layers has a distribution of measured inclination angles on the (0001) plane within the range of 0 to 10 degrees for the first unit layer and 75 to 85 degrees for the second unit layer. An inclination angle distribution graph in which the highest peak appears is shown. On the other hand, the intermediate layer of the coated cermet tools 1 to 13 of the present invention and the deposited α-type Al ₂ O ₃ layer of the conventional coated cermet tools 1 to 13 have a measured inclination angle distribution on the (0001) plane of 0 to 90 degrees. The inclination angle number distribution graph in which the highest peak is not present in any range is shown.
Tables 4 to 7 show the total inclinations existing in the inclination angle sections in the range of 0 to 10 degrees and 75 to 85 degrees in the inclination angle number distribution graphs of the various deposited α-type Al ₂ O ₃ layers. The ratio of the number of angles to the entire gradient number distribution graph is shown.
3 is an inclination angle number distribution graph of the first unit layer constituting the upper layer of the coated cermet tool 1 of the present invention, FIG. 4 is an inclination angle number distribution graph of the second unit layer, and FIGS. the inclination angle frequency distribution graph, respectively showing the inclination angle segment of 0 to 45 degrees and 45-90 degrees coated cermet constituting the upper layer of the tool 1 deposited α-type the Al ₂ O ₃ 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: JIS-S50C
Cutting speed: 350 m / min. ,
Cutting depth: 2.0 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 0.2 mm / rev.),
Work material: JIS-SCM440,
Cutting speed: 400 m / min. ,
Incision: 4.0 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 8 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: JIS-FC300
Cutting speed: 500 m / min. ,
Cutting depth: 4.5 mm,
Feed: 0.3 mm / rev. ,
Cutting time: 7 minutes,
The dry continuous high-speed, high-cut cutting test (normal cutting speed and cutting is 250 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 8.

From the results shown in Tables 4 to 8, each of the coated cermet tools 1 to 13 of the present invention has a three-layer laminated structure in which the upper layer of the hard coating layer is a first unit layer, a second unit layer, and an intermediate layer, Each of the first and second unit layers has an inclination angle number distribution graph of (0001) plane within the range of 0 to 10 degrees for the first unit layer and 75 to 85 degrees for the second unit layer. The highest peak is shown in the corner section, and the distribution of the measured inclination angle on the (0001) plane is unbiased within the range of 0 to 90 degrees, and there is no highest peak between the first unit layer and the second unit layer. Since the intermediate layer showing the inclination angle number distribution graph is interposed, the internal stress and internal strain of the upper layer are extremely small, and the adhesiveness is excellent, and a good quality upper layer can be formed, and The upper layer has excellent high temperature strength and hardness. From Rukoto, the cutting of steel and cast iron, be carried out in a high speed, and high mechanical shock accompanied by Nau fast heavy cutting conditions, without chipping, exhibit excellent wear resistance. On the other hand, the entire upper layer of the hard coating layer has an inclination angle number distribution graph in which the distribution of measured inclination angles on the (0001) plane is unbiased within the range of 0 to 45 degrees and 45 to 90 degrees, and the highest peak does not exist. In the conventional coated cermet tools 1 to 13 composed of the vapor-deposited α-type Al ₂ O ₃ layer shown, all of the high-speed heavy cutting conditions were caused by the lack of high-temperature strength and high-temperature hardness of the vapor-deposited α-type Al ₂ O ₃ layer. Then, it is clear that chipping occurs in the hard coating layer 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.

It is a schematic diagram illustrating a measurement range of the inclination angle of the case of measuring the crystal grains in the first unit layer deposition α type the Al ₂ O ₃ layer constituting the upper layer of the hard coating layer (0001) plane. Is a schematic diagram illustrating a measurement range of the inclination angle of the case of measuring the crystal grains in the second unit layer deposition α type the Al ₂ O ₃ layer constituting the upper layer of the hard coating layer (0001) plane. It is an inclination angle number distribution graph of the (0001) plane of the first unit layer constituting the upper layer of the hard coating layer of the coated cermet tool 1 of the present invention. It is an inclination angle number distribution graph of the (0001) plane of the 2nd unit layer which constitutes the upper layer of the hard covering layer of the present covering cermet tool 1. The inclination angle frequency distribution graph showing the tilt angle sections of 0 to 45 degrees of conventional coated cermet deposited α-type constituting the hard layer of the tool 1 Al ₂ O ₃ layer (0001) plane. The inclination angle frequency distribution graph showing the tilt angle sections of 45 to 90 degrees prior coated cermet deposited α-type constituting the hard layer of the tool 1 Al ₂ O ₃ 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) an aluminum oxide layer in which the upper layer has an α-type crystal structure in the state of chemical vapor deposition and has an overall average layer thickness of 3.5 to 11 μm;
In the surface-coated cermet cutting tool formed by vapor-depositing the hard coating layer composed of (a) and (b) above,
The aluminum oxide layer includes a first unit layer having an average layer thickness of 1.5 to 5 μm, a second unit layer having an average layer thickness of 1.5 to 5 μm, a first unit layer and a second unit layer, A crystal grain having a hexagonal crystal lattice existing in a measurement range of a polished surface parallel to the tool substrate surface using a field emission scanning electron microscope, and having a three-layer laminated structure including an intermediate layer interposed therebetween Individually irradiated with an electron beam, 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. The first unit layer is 0 to 45 degrees, the second unit layer is 45 to 90 degrees, and the intermediate layer is divided into 0 to 90 degrees for each inclination angle of 0.25 degrees. In addition, the inclination angle frequency distribution graph is formed by counting the frequencies existing in each category. When it appears in
(A) In the first unit layer, the highest peak exists in the inclination angle section in the range of 0 to 10 degrees, and the total of the frequencies existing in the range of 0 to 10 degrees is an inclination angle number distribution graph. The inclination angle frequency distribution graph which occupies the ratio of 45-65% of the whole frequency in is shown,
(B) In the second unit layer, the highest peak exists in the inclination angle section in the range of 75 to 85 degrees, and the total of the frequencies existing in the range of 75 to 85 degrees is an inclination angle number distribution graph. Showing an inclination angle frequency distribution graph occupying a proportion of 45 to 65% of the entire frequency in
(C) The intermediate layer shows a gradient angle distribution graph in which there is no peak over the entire measurement gradient segment in the range of 0 to 90 degrees, and the distribution of measurement gradients is unbiased.
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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