JP2007168029A - Surface coated cermet-made cutting tool having hard coating layer exhibiting excellent chipping resistance in high-speed cutting material hard to cut - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cermet-made cutting tool having a hard coating layer exhibiting excellent chipping resistance in high-speed cutting material hard to cut. <P>SOLUTION: In this surface coated cermet-made tool, on the surface of a tool base, a hard coating layer is formed. The hard coating layer includes: a lower layer, which is a Ti compound layer 3 to 20 μm; an interlayer contact layer, which is a contact α type Al<SB>2</SB>O<SB>3</SB>layer 0.1 to 1.9 μm; and an upper layer, which is a modified α type Al<SB>2</SB>O<SB>3</SB>1.5 to 5.9 μm. An inclination angle frequency distribution graph is created by measuring an angle of inclination made by a normal of a face, which is a crystalline plane of a crystal grain using a field emission scanning electron microscope. The upper layer and the interlayer contact layer are formed by α type Al<SB>2</SB>O<SB>3</SB>layer, which has the highest peak in sections of inclination angle ranging from 30 to 45 degrees and ranging from 75 to 90 and shows an inclination angle frequency distribution graph in which the total frequency present in the inclination angle sections occupies the ratio of 50% or more of the entire frequency. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  This invention has a high viscosity, and has a high adhesion to the hard coating layer on the surface of the cutting tool during cutting. As a result, mild steel, stainless steel, and high manganese steel that have extremely high cutting resistance. This is a surface-coated cermet cutting tool (hereinafter referred to as a coated cermet tool) that exhibits excellent chipping resistance with a hard coating layer in high-speed cutting of difficult-to-cut materials, and exhibits excellent wear resistance over a long period of time. It is.

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 having a total average layer thickness of 3 to 20 μm, including one or two or more of a layer and a carbonitride oxide (hereinafter referred to as TiCNO) layer,
(B) The upper layer has an average layer thickness of 1 to 15 μm and has an α-type crystal structure in a state of chemical vapor deposition (hereinafter referred to as a conventional α-type Al ₂ O ₃ layer),
A coated cermet tool formed by vapor-depositing a hard coating layer composed of (a) and (b) above is known, and this coated cermet tool is used for cutting various steels and cast irons, for example. Is well known.

Further, in the above-described coated cermet tool, the constituent layer of the hard coating layer generally has a granular crystal structure, and further, the TiCN layer constituting the Ti compound layer as the lower layer is intended to improve the strength of the layer itself. In a normal chemical vapor deposition apparatus, a gas mixture containing organic carbonitrides is used as a reaction gas, and it is formed by chemical vapor deposition at an intermediate temperature range of 700 to 950 ° C. so that it has a vertically grown crystal structure. It is also known to do.
Japanese Unexamined Patent Publication No. 6-31503 Japanese Patent Laid-Open No. 6-8010

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. In coated cermet tools, there is no problem when used for high-speed cutting of general steel such as low alloy steel and carbon steel, and ordinary cast iron such as gray cast iron. When used for high-speed cutting of difficult-to-cut materials such as high-manganese steel, the difficult-to-cut material itself has a high viscosity and has high adhesion to the hard coating layer on the surface of the cutting tool during cutting. The tendency, combined with the further increase due to the high heat generated during high-speed cutting, has extremely high cutting resistance, while the high-temperature strength of the conventional α-type Al ₂ O ₃ layer that constitutes the hard coating layer can withstand this. As a result, chipping (slight chipping) is likely to occur in the cutting edge portion, and the service life is reached in a relatively short time due to this.

In view of the above, the present inventors have focused on the conventional coated cermet tool in which the conventional α-type Al ₂ O ₃ layer constitutes the upper layer of the hard coating layer, and in particular, the conventional α-type Al ₂ O ₃ layer result to conducted research promote chipping resistance improving,
(A) The conventional α-type Al ₂ O ₃ layer as 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 conventional α-type Al ₂ O ₃ layer formed under the normal conditions is formed using a field emission scanning electron microscope, and is shown in FIGS. 1 (a), 1 (b) and FIG. 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. When the measured inclination angle within the range is divided for each pitch of 0.25 degrees, and an inclination angle number distribution graph is created by summing up the frequencies existing in each division, FIG. 45 degrees) and FIG. 6 (measurement tilt angle: 45 to 90 degrees), The distribution of the measured inclination angle of the (0001) plane should be an unbiased inclination angle number distribution graph regardless of the range of 0 to 45 degrees and 45 to 90 degrees.

(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:% by volume, AlCl ₃ : 3 to 10%, CO ₂ : 0.5 to 3%, HCl: 0.3 to 3%, SF ₆ : 0.01 to 0.2%, C ₂ H _{4: 0.01~0.3%,} H _2: remainder,
Reaction atmosphere temperature: 950 to 1050 ° C.
Reaction atmosphere pressure: 20-30 kPa,
In other words, the reaction gas composition is adjusted to a reaction gas composition different from the reaction gas composition under the normal conditions described above, and in comparison with the temperature and pressure of the reaction atmosphere under the normal conditions. When formed under the conditions of low temperature and high pressure, the α-type Al ₂ O ₃ layer formed as a result of the same was obtained using the field emission scanning electron microscope, as shown in FIGS. 1 (a) and 1 (b). The crystal grains having a hexagonal crystal lattice existing in the measurement range of the polished surface parallel to the electron beam are irradiated with an electron beam, and are the crystal planes of the crystal grains with respect to the normal line of the polished surface (0001) The tilt angle formed by the normal of the surface is measured, 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. When represented by a graph showing the distribution of the number of tilt angles In this case, as illustrated in FIG. 3, a sharp maximum peak appears at a specific position of the tilt angle section. According to the test results, the formation conditions of the α-type Al ₂ O ₃ layer, that is, the reaction gas composition and When at least one of the reaction atmosphere conditions is changed within the above range, the position at which the sharpest peak appears changes within the range of 30 to 45 degrees of the tilt angle section, and the above 30 to The total of the frequencies existing in the 45 degree range occupies a ratio of 50% or more of the entire frequency in the inclination angle frequency distribution graph, and in the resulting inclination angle frequency distribution graph, it is in the range of 30 to 45 degrees. The α-type Al ₂ O ₃ layer (hereinafter referred to as a modified α-type Al ₂ O ₃ layer) in which the highest peak of the tilt angle section appears is compared with the conventional α-type Al ₂ O ₃ layer formed under the above normal conditions, Excellent high temperature strength It must be something.

(C) Furthermore, using 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,
When the α type the Al ₂ O ₃ layer at conditions to form with an average layer thickness of 0.1～1.9Myuemu, the result formed α-type Al ₂ O ₃ layer is also has a α-type crystal structure, Using a field emission scanning electron microscope, as shown in FIGS. 2A and 2B, each crystal grain having a hexagonal crystal lattice, which is also present in the measurement range of the polished surface parallel to the tool substrate surface, is used. By irradiating 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. FIG. 4 shows an example of a tilt angle distribution graph in which the measured tilt angles within a range of degrees are divided into pitches of 0.25 degrees and the frequencies existing in each section are tabulated. A sharp peak appears at a specific position in the slope angle section. When the reaction atmosphere temperature and pressure are changed within the range of 750 to 900 ° C. and 20 to 30 kPa as described above, the position at which the sharpest peak appears changes within the range of 75 to 90 degrees of the inclination angle section. At the same time, the sum of the frequencies existing within the range of 75 to 90 degrees occupies a ratio of 50% or more of the entire frequencies in the inclination angle distribution graph, and 75 to 90 in the inclination angle distribution graph as a result. The Al ₂ O ₃ layer (hereinafter referred to as the adhesion α-type Al ₂ O ₃ layer) in which the highest peak of the tilt angle section appears in the range of degrees is the above-mentioned modified α-type Al ₂ O ₃ layer (upper layer) and Ti It must have the property of adhering remarkably firmly to any of the compound layers (lower layers).

(D) Therefore, after the upper layer is specified to have a relatively thin average layer thickness of 1.5 to 5.9 μm, the modified α-type Al ₂ O ₃ layer having excellent high-temperature strength as described in (b) above. And the adhesion α-type Al ₂ O ₃ layer of the above (c), which is extremely firmly adhered to both of the upper layer and the lower Ti compound layer, is 0.1 to 1.9 μm. The coated cermet tool formed by vapor-depositing a hard coating layer having a structure having an average layer thickness on the surface of the tool base is also used in the high-speed cutting of the above difficult-to-cut material with extremely high cutting resistance. Chipping does not occur in the layer, and as a result, excellent wear resistance is exhibited over a long period of time.
The research results (a) to (d) have been obtained.

This invention was made based on the above research results, and on the surface of the tool base,
(A) As a lower layer, a Ti compound layer comprising one or more of a TiC layer, a TiN layer, a TiCN layer, a TiCO layer, and a TiCNO layer, and having a total average layer thickness of 3 to 20 μm,
(B) As an interlayer adhesion layer between the lower layer and the upper layer described below, a polishing surface having an α-type crystal structure in the state of chemical vapor deposition and parallel to the tool substrate surface using a field emission scanning electron microscope Inclination made by irradiating an electron beam to each crystal grain having a hexagonal crystal lattice existing in the range and a normal line of the (0001) plane being the crystal plane of the crystal grain with respect to the normal line of the polished surface An angle is measured, and the measured inclination angle within the range of 45 to 90 degrees is divided into 0.25 degree pitches among the measured inclination angles, and the degrees existing in each division are totaled. In the angle distribution graph,
The highest peak exists in the inclination angle section in the range of 75 to 90 degrees, and the total of the frequencies existing in the range of 75 to 90 degrees represents a ratio of 50% or more of the entire degrees in the inclination angle frequency distribution graph. A close contact α-type Al ₂ O ₃ layer showing an inclination angle number distribution graph and having an average layer thickness of 0.1 to 1.9 μm;
(C) As an upper layer, a hexagonal crystal having an α-type crystal structure in the state of chemical vapor deposition and existing in a measurement range of a polished surface parallel to the tool substrate surface using a field emission scanning electron microscope By irradiating each crystal grain having a crystal lattice 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. In the inclination angle number distribution graph formed by totaling the frequencies existing in each division, while dividing the measurement inclination angle in the range of 0 to 45 degrees among the inclination angles for each pitch of 0.25 degrees,
The highest peak exists in the inclination angle section within the range of 30 to 45 degrees, and the total of the frequencies existing within the range of 30 to 45 degrees represents a ratio of 50% or more of the entire degrees in the inclination angle frequency distribution graph. A modified α-type Al ₂ O ₃ layer showing an occupying inclination number distribution graph and having an average layer thickness of 1.5 to 5.9 μm;
It is characterized by a coated cermet tool that exhibits excellent chipping resistance in high-speed cutting of difficult-to-cut materials formed by vapor-depositing the hard coating layer composed of (a) to (c) above. is there.

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 a lower layer of the modified α-type Al ₂ O ₃ layer, which is the upper layer, and allows the hard coating layer to have high temperature strength by its excellent high temperature strength. In addition, it firmly adheres to both the tool base and the close contact α-type Al ₂ O ₃ layer, and thus has an effect of improving the adhesion of the hard coating layer to the tool base, but if the total average layer thickness is less than 3 μm When the total average layer thickness exceeds 20 μm, the high-speed cutting of difficult-to-cut materials with high heat generation is likely to cause thermoplastic deformation, which is uneven wear. Therefore, the total average layer thickness was determined to be 3 to 20 μm.

(B) modified α type the Al ₂ O ₃ layer (upper layer)
As described above, the maximum peak position and the frequency distribution ratio of the measured inclination angle in the inclination angle number distribution graph of the modified α-type Al ₂ O ₃ layer are at least one of the reaction gas composition and the reaction atmosphere conditions. Although it changes by changing within the above range, according to the test results, the highest peak appears in the inclination angle section within the range of 30 to 45 degrees and the frequency existing within the range of 30 to 45 degrees. In addition to the excellent high-temperature hardness and heat resistance of α-type Al ₂ O ₃ itself, when the inclination angle distribution graph occupies 50% or more of the total frequency in the inclination angle distribution graph It will have excellent high temperature strength.
If the average layer thickness is less than 1.5 μm, the hard coating layer cannot be sufficiently provided with the above characteristics. On the other hand, if the average layer thickness exceeds 5.9 μm, high-speed cutting of difficult-to-cut materials is possible. Since chipping is likely to occur during processing, the average layer thickness is set to 1.5 to 5.9 μm.

(C) Adhesive α-type Al ₂ O ₃ layer (interlayer adhesion layer)
As described above, the maximum peak position and the frequency distribution ratio of the measured inclination angle in the inclination angle number distribution graph of the contact α-type Al ₂ O ₃ layer are the reaction atmosphere temperature and pressure in the chemical vapor deposition apparatus as described above, 750 to 900 ° C. However, according to the test results, the highest peak appears in the inclination angle section in the range of 75 to 90 degrees, and exists in the range of 75 to 90 degrees. summing the power is to indicate an inclination angle frequency distribution graph in a proportion of 50% or more of the total power at the inclination angle frequency distribution graph, the above upper layer (reformed α-type the Al ₂ O ₃ layer) and a lower layer For any of the (Ti compounds), excellent adhesion is exhibited.
On the other hand, if the average layer thickness is less than 0.1 μm, the desired excellent adhesion cannot be ensured. On the other hand, if the average layer thickness exceeds 1.9 μm, chipping is required for high-speed cutting of difficult-to-cut materials. Therefore, the average layer thickness was determined to be 0.1 to 1.9 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 the thickness is less than 0.1 μm, a sufficient discrimination effect cannot be obtained, while the discrimination effect by the TiN layer is sufficient for an average layer thickness of up to 1 μm.

In the coated cermet tool of the present invention, the modified α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer is excellent in addition to the excellent high-temperature hardness and heat resistance of the α-type Al ₂ O ₃ itself. Since the adhesive α-type Al ₂ O ₃ layer having high-temperature strength and interposed between the modified α-type Al ₂ O ₃ layer and the Ti compound layer adheres very firmly to both, the cutting resistance Even in high-speed cutting of difficult-to-cut materials, the hard coating layer exhibits excellent wear resistance without occurrence of chipping, and the service life can be further extended.

  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 was blended in the blending composition shown in Table 1, and then added with wax, mixed in a ball mill for 24 hours in acetone, dried under reduced pressure, and then 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.

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

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, reaction gas composition: volume%, AlCl ₃ : 2.2%, CO ₂ : 5%, HCl: 2%, H ₂ S: 0.15%, H ₂ : remaining,
Reaction atmosphere temperature: 850 ° C.
Reaction atmosphere pressure: a predetermined pressure in the range of 20-30 kPa,
With the target layer thicknesses shown in Tables 4 and 5 under the conditions described above, an adhesion α-type Al ₂ O ₃ layer is formed by vapor deposition.
(C) Furthermore, the reaction gas composition: volume%, AlCl ₃ : 4%, CO ₂ : 1.5%, HCl: 2%, SF ₆ : 0.1%, C ₂ H ₄ : 0.15%, H ₂ : Remaining
Reaction atmosphere temperature: 1000 ° C.
Reaction atmosphere pressure: a predetermined pressure in the range of 20-30 kPa,
The coated cermet tools 1 to 13 of the present invention were manufactured by depositing a modified α-type Al ₂ O ₃ layer as an upper layer, with the target layer thicknesses shown in Tables 4 and 5 under the same conditions.

For comparison purposes, the formation of the conventional α-type Al ₂ O ₃ layer, which is 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,
Of the conventional α-type Al ₂ O ₃ layer and the lower Ti compound layer, as shown in Tables 6 and 7, respectively. Conventionally coated cermet tools 1 to 13 were manufactured under the same conditions except that no interlayer adhesion layer was formed therebetween.

Subsequently, the modified α-type Al ₂ O ₃ layer and the conventional α-type Al ₂ O ₃ 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 conventional coated cermet tool 1-13, for adhesion α type the Al ₂ O ₃ layer of the invention described above coated cermet tools 1 to 13, using a field emission scanning electron microscope, were prepared, respectively the inclination angle frequency distribution graph.
That is, the inclination angle number distribution graph shows the electric field in a state where the surfaces parallel to the tool base surface are polished surfaces for the various α-type Al ₂ O ₃ layers of the above-described coated cermet tools 1 to 13 of the present invention. A hexagon set in the barrel of an emission scanning electron microscope and having an electron beam with an acceleration voltage of 15 kV at an incident angle of 70 degrees on the polished surface at an irradiation current of 1 nA and within the measurement range of each polished surface. Each crystal grain having a crystal lattice is irradiated, and an electron backscatter diffraction image apparatus is used, and the crystal grain is 30 × 50 μm at a spacing of 0.1 μm / step with respect to the normal of the polished surface. The tilt angle formed by the normal line of the (0001) plane, which is the crystal plane, is measured, and based on the measurement result, of the measured tilt angle, the modified α-type Al ₂ O ₃ layer is 0 to 45 degrees. , One in the contact α type the Al ₂ O ₃ layer The converting mechanism divides the measured tilt angle within a range of 45 to 90 degrees for each pitch of 0.25 degrees, was created by aggregating the frequencies present in each segment.
In addition, for the conventional α-type Al ₂ O ₃ layers of the conventional coated cermet tools 1 to 13, an arbitrary polished surface parallel to the tool base surface is observed under the same conditions, and an inclination angle number distribution graph is displayed under the same conditions. Created.

In the inclination angle number distribution graphs of the various α-type Al ₂ O ₃ layers obtained as a result, as shown in Tables 4 to 7, modified α-type Al ₂ O ₃ layers of the coated cermet tools 1 to 13 of the present invention, respectively. And the close contact α-type Al ₂ O ₃ layer, in which the distribution of the measured inclination angle on the (0001) plane is 30 to 45 degrees in the former and 75 to 90 degrees in the latter, and the inclination in which the highest peak appears in the inclination angle section. In contrast to the angle distribution graph, the conventional α-type Al ₂ O ₃ layer of the conventional coated cermet tools 1 to 13 has a distribution of measured inclination angles on the (0001) plane of 0 to 45 degrees and 45 to 90 degrees. An inclination angle number distribution graph that is unbiased within the range and does not have the highest peak is shown.
Tables 4 to 7 show the total inclination angles existing in the inclination angle sections in the range of 30 to 45 degrees and 75 to 90 degrees in the inclination angle number distribution graphs of the various α-type Al ₂ O ₃ layers. The ratio of the number to the whole angle distribution graph is shown.
3 is an inclination angle number distribution graph of the modified α-type Al ₂ O ₃ layer (upper layer) of the coated cermet tool 5 of the present invention, and FIG. 4 is the same contact α-type Al ₂ O ₃ layer (interlayer adhesion layer). 5 and 6 are inclination angle distribution graphs showing inclination angle sections of 0 to 45 degrees and 45 to 90 degrees of the conventional α-type Al ₂ O ₃ layer of the conventional coated cermet tool 6, respectively. .

  Moreover, when the thickness of the constituent layer of the hard coating layer of the present 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 / SUS316L lengthwise equidistant four round grooved round bars,
Cutting speed: 330 m / min. ,
Incision: 1.5mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes
Dry intermittent high-speed cutting test (normal cutting speed 150 m / min.) Of stainless steel under the following conditions (referred to as cutting conditions A),
Work material: JIS / SS400 lengthwise equidistant 4 round bars with flutes,
Cutting speed: 450 m / min. ,
Cutting depth: 1mm,
Feed: 0.25 mm / rev. ,
Cutting time: 5 minutes
Dry interrupted high-speed cutting test (normal cutting speed is 200 m / min.) Of mild steel under the following conditions (referred to as cutting conditions B),
Work material: JIS / SCMnH1 round bar,
Cutting speed: 430 m / min. ,
Incision: 1.5mm,
Feed: 0.3 mm / rev. ,
Cutting time: 5 minutes
The dry continuous high-speed cutting test (normal cutting speed is 250 m / min.) Of high manganese steel under the above conditions (referred to as 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 8.

From the results shown in Tables 4 to 8, the coated cermet tools 1 to 13 of the present invention are all (0001) plane inclination angle number distribution graphs, and modified α-type Al ₂ O ₃ which is the upper layer of the hard coating layer. The layer is inclined at an angle in the range of 30 to 45 degrees, and the contact α-type Al ₂ O ₃ layer interposed between the upper and lower Ti compound layers is in the range of 75 to 90 degrees. Each of the inclination angle sections shows the highest peak, and the frequency distribution ratio in each of the inclination angle sections shows 50% or more. As a result, the modified α-type Al ₂ O ₃ layer has excellent high-temperature hardness and heat resistance. In addition, it has excellent high-temperature strength, while the adhesion α-type Al ₂ O ₃ layer exhibits excellent adhesion, so that no chipping occurs even at high-speed cutting of difficult-to-cut materials with extremely high cutting resistance. Hard coating, while showing excellent wear resistance The conventional α-type Al in which the upper layer of the layer shows an inclination angle distribution graph in which the distribution of the measured inclination angle of 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 consists ₂ O ₃ layer, and in the contact α type the Al ₂ O ₃ layer prior coated cermet tools 1 to 13 with no intervening formation are all due to insufficient strength of the hard coating layer, high-speed cutting of difficult-to-cut materials It is clear that chipping occurs in the hard coating layer during processing, and the service life is reached in a relatively short time.

  As described above, the coated cermet tool of the present invention has high viscosity in addition to high-speed cutting such as various types of steel and cast iron, and has a high viscosity with respect to the hard coating layer on the surface of the cutting tool at the time of cutting. Even with high-speed cutting of difficult-to-cut materials such as mild steel, stainless steel, and high-manganese steel, which have high adhesion and high cutting resistance as a result, it exhibits excellent wear resistance without chipping. Since it exhibits excellent cutting performance, it can sufficiently satisfy the high performance of the cutting device, the labor saving and energy saving of the cutting work, and the cost reduction.

It is a schematic diagram illustrating a measurement range of the inclination angle of 0 to 45 degrees when measuring the crystal grain of the various α-type the Al ₂ O ₃ layer constituting the hard coating layer (0001) plane. It is a schematic diagram illustrating a measurement range of the inclination angle of 45 to 90 degrees when measuring the crystal grain of the various α-type the Al ₂ O ₃ layer constituting the hard coating layer (0001) plane. The inclination angle frequency distribution graph showing the tilt angle sections of 0 to 45 degrees of the modified α type the Al ₂ O ₃ layer constituting the upper layer of the hard coating layer of the present invention coated cermet tool 5. The inclination angle frequency distribution graph showing the tilt angle sections of 45 to 90 degrees of the contact α type the Al ₂ O ₃ layer constituting the interlayer adhesion layer of the hard coating layer of the present invention coated cermet tool 5. The inclination angle frequency distribution graph showing the tilt angle sections of 0 to 45 degrees of conventional α form the Al ₂ O ₃ layer constituting the upper layer of the hard coating layer of the conventional coated cermet tool 6. The inclination angle frequency distribution graph showing the tilt angle sections of 45 to 90 degrees to the conventional coated cermet conventional α type the Al ₂ O ₃ layer constituting the hard coating layer of the tool 6.

Claims (1)

On the surface of the tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(A) As a lower layer, it consists of one or more of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer, and carbonitride oxide layer, and a total average of 3 to 20 μm A Ti compound layer having a layer thickness,
(B) As an interlayer adhesion layer between the lower layer and the upper layer described below, a polishing surface having an α-type crystal structure in the state of chemical vapor deposition and parallel to the tool substrate surface using a field emission scanning electron microscope Inclination made by irradiating an electron beam to each crystal grain having a hexagonal crystal lattice existing in the range and a normal line of the (0001) plane being the crystal plane of the crystal grain with respect to the normal line of the polished surface An angle is measured, and the measured inclination angle within the range of 45 to 90 degrees is divided into 0.25 degree pitches among the measured inclination angles, and the degrees existing in each division are totaled. In the angle distribution graph,
The highest peak exists in the inclination angle section in the range of 75 to 90 degrees, and the total of the frequencies existing in the range of 75 to 90 degrees represents a ratio of 50% or more of the entire degrees in the inclination angle frequency distribution graph. An α-type aluminum oxide layer showing an inclination angle number distribution graph and having an average layer thickness of 0.1 to 1.9 μm;
(C) As an upper layer, a hexagonal crystal lattice having an α-type crystal structure in a chemically vapor-deposited state and existing in a measurement range of a polished surface parallel to the tool substrate surface using a field emission scanning electron microscope And measuring the inclination angle formed by the normal line of the (0001) plane, which is the crystal plane of the crystal grain, with respect to the normal line of the polished surface. In the inclination angle number distribution graph formed by dividing the measured inclination angles in the range of 0 to 45 degrees for each pitch of 0.25 degrees and totaling the frequencies existing in each section,
The highest peak exists in the inclination angle section within the range of 30 to 45 degrees, and the total of the frequencies existing within the range of 30 to 45 degrees represents a ratio of 50% or more of the entire degrees in the inclination angle frequency distribution graph. An α-type aluminum oxide layer showing an occupying angle number distribution graph and having an average layer thickness of 1.5 to 5.9 μm;
A surface-coated cermet cutting tool that exhibits excellent chipping resistance in high-speed cutting of difficult-to-cut materials formed by vapor-depositing the hard coating layer composed of (a) to (c) above.

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