JP2007196355A - Surface coated cermet cutting tool having hard coating layer exhibiting excellent chipping resistance in cutting difficult-to-cut material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cermet cutting tool having a hard coating layer exhibiting excellent chipping resistance in cutting difficult-to-cut material. <P>SOLUTION: This cutting tool is a surface coated cermet tool formed by depositing the hard coating layer including: a lower layer formed of a Ti compound layer with an average layer thickness ranging from 3 to 20 μm; and an upper layer formed of a reformed α-type Al<SB>2</SB>O<SB>3</SB>layer with an average layer thickness ranging from 6 to 20 μm on the surface of a tool base. In the tool, as a reinforcement layer, an α-type Al<SB>2</SB>O<SB>3</SB>layer is interposed between the lower layer and the upper layer of the tool. In the case of measuring an angle of inclination made by a normal of (0001) face, which is a crystal plane of a crystal grain, using a field emission type scanning electron microscope to create an inclination angle frequency distribution graph, the α-type Al<SB>2</SB>O<SB>3</SB>layer shows an inclination angle frequency distribution graph in which the highest peak exists in an inclination angle section within the range of 75 to 90 degrees, and the total of frequencies existing in the range of 75 to 90 degrees occupies 50% or more of the whole frequency, and has an average layer thickness ranging from 0.1 to 1.9 μm. Further, the surface roughness of the reformed α-type Al<SB>2</SB>O<SB>3</SB>layer is set to Ra: 0.2 μm or less. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  This invention has a high viscosity and has high adhesion to the hard coating layer on the surface of the cutting tool during cutting. As a result, soft steel, stainless steel, and high manganese steel that have high cutting resistance The present invention relates to a surface-coated cermet cutting tool (hereinafter referred to as a coated cermet tool) that exhibits excellent chipping resistance in hard-cutting materials and exhibits excellent wear resistance over a long period of time. .

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 α-type crystal structure in the state of chemical vapor deposition, and using a field emission scanning electron microscope, as shown schematically in FIG. 2, is a polished surface parallel to the tool base surface. Each of the crystal grains having a hexagonal crystal lattice existing within the measurement range is irradiated with an electron beam, and the normal line of the (0001) plane that is the crystal plane of the crystal grain is relative to the normal line of the polished surface. Measure the inclination angle to be made, divide the measurement inclination angle within the range of 0-45 degrees out of the measurement inclination angle for each pitch of 0.25 degree, and totalize the frequency existing in each division In the inclination angle number distribution graph, as shown in FIG. 4, the highest peak exists in the inclination angle section in the range of 0 to 15 degrees, and the sum of the frequencies existing in the range of 0 to 15 degrees is as follows. , Accounting for 50% or more of the total frequency in the slope angle distribution graph Shows an inclination angle frequency distribution graph, and an aluminum oxide layer having an average layer thickness of 6 to 20 .mu.m (hereinafter, referred to as modified α type the Al ₂ O ₃ layer),
A coated cermet tool formed by vapor-depositing a hard coating layer composed of the above (a) and (b) is known, and this coated cermet tool has the modified α-type Al ₂ O ₃ layer formed of α-type Al. ₂ O ₃ itself has excellent high-temperature hardness and heat resistance, as well as excellent high-temperature strength, so it has excellent resistance when used for cutting of various general steels and ordinary cast iron, for example. It is known that it exhibits chipping properties and exhibits excellent cutting performance over a long period of time.

In general, the modified α-type Al ₂ O ₃ layer constituting the hard coating layer of the above coated cermet tool uses a normal chemical vapor deposition apparatus,
Reaction gas composition: by _{volume%, AlCl 3: 1~5%,} CO 2: 0.1~2%, HCl: 0.3~3%, H 2 S: 0.5~1%, Ar: 20~ 35%, H ₂ : remaining,
Reaction atmosphere temperature: 1050 to 1100 ° C.
Reaction atmosphere pressure: 6 to 10 kPa,
It is also known that vapor deposition is performed under the following conditions.
Furthermore, the Ti compound layer and the modified α-type Al ₂ O ₃ layer that also constitute the hard coating layer have a granular crystal structure, and the TiCN layer that constitutes the Ti compound layer is intended to improve the strength of the layer itself. In a normal chemical vapor deposition apparatus, a mixed gas containing organic carbonitride is used as a reaction gas, and it is formed by chemical vapor deposition at a medium temperature range of 700 to 950 ° C. so that it has a vertically grown crystal structure. It is also known to do.
JP-A-2005-205586 Japanese Patent Laid-Open No. 6-8010

In recent years, the use of FA for cutting machines 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. However, in the conventional coated cermet tool described above, there is a tendency to require a cutting tool that can cut as many kinds of work materials as possible with one kind of cutting tool. There is no problem when it is used for cutting general steel such as low alloy steel and carbon steel, and ordinary cast iron such as gray cast iron, but this is especially suitable for difficult-to-cut materials such as mild steel, stainless steel, and high manganese steel. When used for cutting, the difficult-to-cut material itself has a high viscosity and also has high adhesion to the hard coating layer on the surface of the cutting tool during cutting, and this tendency increases due to the high heat generated during cutting. This Coupled with I, it becomes having high cutting resistance, whereas the high temperature strength of the modified α type the Al ₂ O ₃ layer constituting the hard coating layer is not sufficient to withstand this, chipping result the cutting edge portion (Slight chipping) is likely to occur, and due to this, the service life is reached in a relatively short time.

In view of the above, the present inventors focused on the coated cermet tool in which the modified α-type Al ₂ O ₃ layer constitutes the upper layer of the hard coating layer, and in particular, the modified α-type Al As a result of research to improve chipping resistance of ₂ O ₃ layer,
(A) Between the Ti compound layer (lower layer) and the modified α-type Al ₂ O ₃ layer (upper layer) constituting the hard coating layer of the conventional coated cermet tool, 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 an aluminum oxide (hereinafter referred to as Al ₂ O ₃ ) layer is formed with an average layer thickness of 0.1 to 1.9 μm under the conditions of the above, the resulting Al ₂ O ₃ layer has the same α-type crystal structure. Using a field emission scanning electron microscope, as shown in FIGS. 1 (a) and 1 (b), it has a hexagonal crystal lattice that is also present in the measurement range of the polished surface parallel to the tool substrate surface. Each crystal grain is irradiated with an electron beam, an inclination angle formed by a normal line of the (0001) plane that is a crystal plane of the crystal grain is measured with respect to the normal line of the polished surface, When the measured inclination angle in the range of 45 to 90 degrees is divided into pitches of 0.25 degrees and the frequency existing in each of the divisions is represented by an inclination angle number distribution graph, FIG. As shown in Fig. 4, a sharp peak appears at a specific position in the tilt angle section, and According to the results, when the reaction atmosphere pressure in the chemical vapor deposition apparatus is changed within the range of 20 to 30 kPa as described above, the position where the sharpest peak appears changes within the range of 75 to 90 degrees of the inclination angle section. In addition, 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 75 in the inclination angle distribution graph as a result. An Al ₂ O ₃ layer (hereinafter referred to as a reinforced α-type Al ₂ O ₃ layer) in which the highest peak of the tilt angle section appears in the range of 90 degrees is referred to as the above-mentioned modified α-type Al ₂ O ₃ layer (upper layer). Since the modified α-type Al ₂ O ₃ layer is sufficiently reinforced between the Ti compound layers (lower layers) and contributes to the improvement of the high-temperature strength thereof, cutting of the above difficult-to-cut materials having high cutting resistance. Also in the processing, the modified α-type Al ₂ Occurrence of chipping in the O ₃ layer is suppressed, and as a result, the coated cermet tool exhibits excellent wear resistance over a long period of time.

(B) On the other hand, the modified α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer of the above-described coated cermet tool has a relatively rough deposition surface. Therefore, an average layer thickness of 0.1 to 2.5 μm is used on the entire surface of the modified α-type Al ₂ O ₃ layer using a normal chemical vapor deposition apparatus under normal conditions, for example, the conditions shown in Table 3. Two or more alternating layers of titanium nitride (hereinafter referred to as TiN) layers and titanium carbonitride (hereinafter referred to as TiCN) layers having a thickness of 0.4 to 5 μm are deposited and formed,
When a polishing liquid containing 15 to 60% by mass of aluminum oxide fine particles (hereinafter referred to as Al ₂ O ₃ fine particles) is injected as a polishing material by wet blasting as a proportion of the total amount with water, the above TiN Alternating layers of two or more layers of layers and TiCN layers (hereinafter referred to as TiN abrasive layer and TiCN abrasive layer, respectively, these are shown as TiN / TiCN abrasive layer) are pulverized by the Al ₂ O ₃ fine particles. Atomized into TiN fine particles and TiCN fine particles, acts as an abrasive in the presence of the Al ₂ O ₃ fine particles, and polishes the surface of the modified α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer As a result, the surface of the modified α-type Al ₂ O ₃ layer after polishing was measured based on the compliant standard JIS B0601-1994 (the following surface roughness is all measured values based on the compliant standard) Indicate) Ra: now be smoothed to a surface roughness of less than 0.2 [mu] m, the surface of the a top layer modification α type the Al ₂ O ₃ layer is Ra: smoothing surface roughness of not more than 0.2 [mu] m When the above-described coated cermet tool is used to cut a difficult-to-cut material, the progress of wear of the modified α-type Al ₂ O ₃ layer is suppressed by smoothing the surface roughness, As a result, the life of the tool can be further extended.
In this case, the TiN / TiCN abrasive layer is not formed on the surface of the modified α-type Al ₂ O ₃ layer. Even if the polishing liquid containing 15 to 60% by mass of Al ₂ O ₃ fine particles is directly sprayed and polished, the surface of the modified α-type Al ₂ O ₃ layer has Ra: 0. A coated cermet tool that is polished only to a surface roughness of 3 to 0.6 μm, and that the resulting surface roughness is an upper layer of a modified α-type Al ₂ O ₃ layer with Ra: 0.3 to 0.6 μm However, when cutting difficult-to-cut materials, sufficient wear-inhibiting effect due to surface smoothing cannot be demonstrated, and satisfactory life span cannot be extended.

(C) As described above, the reinforced α-type Al ₂ O ₃ layer is between the modified α-type Al ₂ O ₃ layer (upper layer) and the Ti compound layer (lower layer), and the modified α-type The Al ₂ O ₃ layer is sufficiently reinforced and contributes to the improvement of the high temperature strength thereof. Further, the rake face portion and the flank portion including at least the cutting edge ridge line portion of the modified α-type Al ₂ O ₃ layer are polished. These coated cermet tools having a polished surface with a surface roughness of Ra: 0.2 μm or less improve the high-temperature strength of the hard coating layer even when cutting difficult-to-cut materials in which high cutting resistance is applied to the cutting edge. And since the modified α-type Al ₂ O ₃ layer of the upper layer has excellent surface smoothness, it exhibits excellent chipping resistance and exhibits excellent wear resistance over a long period of time. thing.
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,
(1) 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 a total average layer thickness of 3 to 20 μm,
(2) The upper layer irradiates an electron beam to each crystal grain having a hexagonal crystal lattice existing in a measurement range of a polished surface parallel to the tool base surface using a field emission scanning electron microscope, The inclination angle formed by the normal line of the (0001) plane that is the crystal plane of the crystal grain is measured with respect to the normal line of the polished surface, and the measurement inclination in the range of 0 to 45 degrees out of the measurement inclination angle In the inclination angle distribution graph obtained by dividing the angle for each pitch of 0.25 degrees and counting the frequencies existing in each section, the highest peak exists in the inclination angle section within the range of 0 to 15 degrees. In addition, an inclination angle number distribution graph in which the sum of the frequencies existing in the range of 0 to 15 degrees occupies a ratio of 50% or more of the entire degrees in the inclination angle number distribution graph is shown, and an average layer thickness of 6 to 20 μm A modified α-type Al ₂ O ₃ layer having
In the coated cermet tool formed by vapor-depositing the hard coating layer composed of (1) and (2) above,
(A) A field emission scanning electron microscope is used as a reinforcing layer between the Ti compound layer as the lower layer and the modified α-type Al ₂ O ₃ layer as the upper layer, and is parallel to the tool base surface. The crystal grains having a hexagonal crystal lattice existing within the measurement range of the polished surface are irradiated with an electron beam, and the method of the (0001) plane that is the crystal plane of the crystal grains with respect to the normal line of the polished surface Measure the tilt angle formed by the line, and divide the measured tilt angle within the range of 45-90 degrees out of the measured tilt angle by pitch of 0.25 degrees, and count the frequency existing in each section In the inclination angle number 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. Reinforced 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,
Intervene,
(B) Furthermore, on the entire surface of the modified α-type Al ₂ O ₃ layer that is the upper layer of the hard coating layer,
Each is composed of two or more alternating layers of TiN abrasive layer having an average layer thickness of 0.1 to 2.5 μm and TiCN abrasive layer, and TiN having an overall average layer thickness of 0.4 to 5 μm / With the TiCN abrasive layer deposited and formed,
In wet blasting, as a spraying abrasive, a polishing liquid containing 15 to 60% by mass of Al ₂ O ₃ fine particles in a proportion of the total amount with water is sprayed,
Modification of the upper layer of the hard coating layer in the presence of pulverized TiN fine particles and pulverized TiCN fine particles by wet blasting of the TiN / TiCN abrasive layer and Al ₂ O ₃ fine particles as a spray abrasive The rake face portion and the flank face portion including at least the cutting edge ridge line portion of the α-type Al ₂ O ₃ layer are polished, and the surface roughness of these polished surfaces is Ra: 0.2 μm or less.
It is characterized by a coated cermet tool that exhibits excellent chipping resistance in a hard coating layer when cutting difficult-to-cut materials.

The reason why the hard coating layer of the coated cermet tool of the present invention, the abrasive layer, and the Al ₂ O ₃ fine particles of the polishing liquid used in wet blasting are numerically limited as described above will be described below.
(A) Hard coating layer (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, and allows the hard coating layer to have high-temperature strength by its excellent high-temperature strength. And the reinforcing α-type Al ₂ O ₃ layer firmly adhere to each other, and thus have an effect of improving the adhesion of the hard coating layer to the tool substrate. However, when the total average layer thickness is less than 3 μm, On the other hand, if the total average layer thickness exceeds 20 μm, thermoplastic deformation tends to occur and this causes uneven wear. Therefore, the total average layer thickness is set to 3 to 20 μm. It was.

(B) modified α type the Al ₂ O ₃ layer (upper layer)
The maximum peak position of the measured inclination angle in the inclination angle number distribution graph of the modified α-type Al ₂ O ₃ layer is changed by changing the reaction atmosphere pressure in the chemical vapor deposition apparatus. When the reaction atmosphere pressure is 6 to 10 kPa, the highest peak appears in the inclination angle section within the range of 0 to 15 degrees, and the total of the frequencies existing within the range of 0 to 15 degrees is the inclination angle. An inclination angle number distribution graph occupying a ratio of 50% or more of the entire frequency in the number distribution graph is shown. Therefore, even if the reaction atmosphere pressure is out of the range, it is out of the range. However, the highest peak of the measured tilt angle does not appear within the range of 0 to 15 degrees, and in such a case, the desired excellent high-temperature strength cannot be provided.
The modified α-type Al ₂ O ₃ layer also has high-temperature strength in addition to the excellent high-temperature hardness and heat resistance of the α-type Al ₂ O ₃ itself, but the average layer thickness is 6 μm. If the average layer thickness is less than 20 μm, chipping is likely to occur in cutting of difficult-to-cut materials. Was determined to be 6 to 20 μm.

(C) Reinforced α-type Al ₂ O ₃ layer (reinforcing layer)
As described above, the highest peak position of the measured inclination angle in the inclination angle number distribution graph of the reinforced α-type Al ₂ O ₃ layer changes by changing the reaction atmosphere pressure in the chemical vapor deposition apparatus, but according to the test results, When the reaction atmosphere pressure in the above deposition conditions is 20 to 30 kPa, the maximum peak appears in the tilt 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 is The inclination angle number distribution graph occupies a ratio of 50% or more of the entire frequency in the inclination angle number distribution graph. Therefore, even if the reaction atmosphere pressure is out of the range, it is high. Even if it deviates, the maximum peak of the measured inclination angle does not appear within the range of 75 to 90 degrees, and in this case, the desired excellent reinforcing action cannot be exhibited. It is a thing.
If the average layer thickness is less than 0.1 μm, the reinforcing action on the modified α-type Al ₂ O ₃ layer is insufficient. On the other hand, if the average layer thickness exceeds 1.9 μm, this is difficult to cut. In this cutting process, chipping occurs, so the average layer thickness is set to 0.1 to 1.9 μm.

(B) TiN / TiCN abrasive material layer As described above, the TiN / TiCN abrasive material layer is pulverized and atomized by Al ₂ O ₃ fine particles blended in the polishing liquid as an injection abrasive material during wet blasting, and TiN fine particles and TiCN fine particles It acts as an abrasive in the coexistence with the Al ₂ O ₃ fine particles, and polishes the surface of the modified α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer. If the average layer thickness of the material layer is less than 0.1 μm, or if the overall average layer thickness of the TiN / TiCN abrasive layer is less than 0.4 μm, the pulverized TiN fine particles and the pulverized TiCN fine particles at the time of wet blasting When the ratio is too small, the polishing function cannot be sufficiently exhibited. On the other hand, the average layer thickness of each abrasive layer exceeds 2.5 μm, or the total average layer thickness of the TiN / TiCN abrasive layer is 5 μm. When or beyond, in unbalanced and Al ₂ O ₃ fine formulated as injection abrasive in the polishing liquid, too many relatively become Again polishing function is rapidly reduced, in any case In addition, the average layer thickness of each abrasive layer is 0.1 to 2.5 μm because the surface of the α-type Al ₂ O ₃ layer cannot be polished to a surface roughness of Ra: 0.2 μm or less. The total average layer thickness was determined to be 0.4 to 5 μm.

(C) The Al ₂ O ₃ fine of Al ₂ O ₃ fine polishing liquid of the polishing liquid, in a state where at the time of wet blast coexists with pulverized TiN / TiCN fine of TiN / TiCN abrasive layer, reforming α-type Al ₂ Although it has an action of polishing the surface of the O ₃ layer, the polishing function will be drastically lowered even if the ratio is less than 15% by mass or more than 60% by mass with respect to the total amount with water. Therefore, the ratio was determined to be 15 to 60% by mass.

Coated cermet tool of the present invention, the reinforcing α-type Al ₂ O ₃ layer is interposed between the reforming α type the Al ₂ O ₃ layer and the Ti compound layer, reforming constituting the upper layer of the hard coating layer The α-type Al ₂ O ₃ layer is sufficiently reinforced and contributes to improving the high-temperature strength of the α-type Al ₂ O ₃ layer. Further, the surface of the modified α-type Al ₂ O ₃ layer is polished to a surface roughness of Ra: 0.2 μm or less. Therefore, even if cutting of difficult-to-cut materials (work materials) such as stainless steel, high manganese steel, and mild steel, which has a high chip viscosity and is easy to weld to the tool surface, The excellent high-temperature strength and smooth surface roughness significantly suppress the occurrence of chipping in the hard coating layer, and also exerts the effect of suppressing wear, resulting in excellent wear resistance over a long period of time. is there.

  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, a tool base made of a WC-based cemented carbide having a throwaway tip shape defined as CNMG12041 in the ISO standard in the form of having a tool mounting bolt through hole in the center. Each of the bodies A to F was produced.

Further, as raw material powders, TiCN (mass ratio, TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC, all having an average particle diameter of 0.5 to 2 μm. Prepare powder, Co powder, and Ni powder, blend these raw material powders into the composition shown in Table 2, wet mix with a ball mill for 24 hours, dry, and press-mold into a green compact at 98 MPa pressure The green compact is sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1540 ° C. for 1 hour, and after sintering, the cutting edge portion is subjected to a honing process of R: 0.07 mm. Made of TiCN-based cermet with a throwaway tip shape that is defined as CNMN12041 in the ISO standard, with no holes attached to the tool body by clamping with clamp pieces To form a tool substrate a~f.

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), the Ti compound layer having the target layer thickness shown in Table 5 is vapor-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,
A reinforced α-type Al ₂ O ₃ layer is formed by vapor deposition at the target layer thickness shown in Table 5 under the conditions of
(C) Furthermore, the reaction gas composition: volume%, AlCl ₃ : 2.2%, CO ₂ : 1.5%, HCl: 2%, H ₂ S: 0.75%, Ar: 26.5%, H ₂ : Remaining
Reaction atmosphere temperature: 1070 ° C.
Reaction atmosphere pressure: a predetermined pressure within a range of 6 to 10 kPa,
The modified α-type Al ₂ O ₃ layer is also formed by vapor deposition with the target layer thickness shown in Table 5 under the same conditions as above,
(D) Further, a TiN / TiCN abrasive material layer is formed by vapor deposition with a target layer thickness shown in Table 6 under the same conditions shown in Table 3.
Subsequently, wet blasting is performed under the blasting conditions shown in Table 4 and in the combinations shown in Table 6, and for the tool bases A to F, the TiN / In the state where the TiCN abrasive layer is left without being removed, and for the tool bases a to f, the TiN / TiCN abrasive layer on the clamp piece abutting surface portion (the center portion of the rake face) is not removed. In the remaining state, the rake face and the flank face including the cutting edge ridge line portion of the modified α-type Al ₂ O ₃ layer (upper layer) are polished to the surface roughness shown in Table 6 to cover the present invention. Cermet tools 1 to 13 were produced, respectively.

For comparison purposes, as shown in Table 7, a reinforced α-type Al ₂ O _{3 is provided} between the modified α-type Al ₂ O ₃ layer as the upper layer of the hard coating layer and the Ti compound layer as the lower layer. Conventionally coated cermet tools 1 to 13 were manufactured under the same conditions except that the layer was not formed and the formation of the TiN / TiCN abrasive layer and the surface polishing treatment by wet blasting were not performed.

Subsequently, the modified α-type Al ₂ O ₃ layer constituting the upper layer of the hard coating layer of the present invention coated cermet tool 1-13 and the conventional coated cermet tool 1-13, and the present invention coated cermet tool 1-1 With respect to the 13 reinforced α-type Al ₂ O ₃ layers, inclination angle number distribution graphs were respectively prepared using a field emission scanning electron microscope.
That is, the inclination angle number distribution graph shows the modified α-type Al ₂ O ₃ layer of the present invention coated cermet tools 1 to 13 and the conventional coated cermet tools 1 to 13 and the reinforcement of the present coated cermet tools 1 to 13. The α-type Al ₂ O ₃ layer is set in a lens barrel of a field emission scanning electron microscope with each surface parallel to the surface of the tool base being a polished surface, and incident on the polished surface at an incident angle of 70 degrees. An electron backscatter diffraction image apparatus is used to irradiate an electron beam having an acceleration voltage of 15 kV with an irradiation current of 1 nA on each crystal grain having a hexagonal crystal lattice existing within the measurement range of each polished 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 at an interval of 0.1 μm / step in a region of × 50 μm. Based on before Among the measurement inclination angle, the 0-45 degrees for reforming α type the Al ₂ O ₃ layer, the measurement inclination angle is in the range of 45 to 90 degrees for the reinforcement α type the Al ₂ O ₃ layer 0.25 This was created by dividing the pitch for each degree and counting the frequencies existing in each division.

In the gradient angle distribution graphs of the various modified α-type Al ₂ O ₃ layers and reinforced α-type Al ₂ O ₃ layers obtained as a result, as shown in Tables 8 and 9, respectively, the coated cermet tools 1 to 1 of the present invention are used. 13 and the modified α-type Al ₂ O ₃ layer of the conventional coated cermet tools 1 to 13, 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 15 degrees, respectively. An inclination angle number distribution graph is shown. On the other hand, in the reinforcing α-type Al ₂ O ₃ layer of the coated cermet tools 1 to 13 of the present invention, an inclination angle number distribution graph in which the highest peak appears in the inclination angle section within the range of 75 to 90 degrees. Was shown.
Tables 8 and 9 show the ranges of 0 to 15 degrees and 75 to 90 degrees in the inclination angle number distribution graphs of the various modified α-type Al ₂ O ₃ layers and reinforced α-type Al ₂ O ₃ layers, respectively. The ratio of the total number of tilt angles existing in the tilt angle section to the entire tilt angle distribution graph is shown.
3 is an inclination angle distribution graph of the reinforcing α-type Al ₂ O ₃ layer of the coated cermet tool 2 of the present invention, and FIG. 4 is an inclination angle distribution graph of the modified α-type Al ₂ O ₃ layer of the tool. It is shown.

  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, with respect to the various coated cermet tools of the present invention coated cermet tools 1 to 13 and the conventional coated cermet tools 1 to 13, all are clamped and clamped to the tip of the tool steel tool by a bolt or a clamp piece so,
Work material: JIS / SUS316 round bar,
Cutting speed: 330 m / min. ,
Cutting depth: 2mm,
Feed: 0.2 mm / rev. ,
Dry continuous cutting test of stainless steel under the conditions (cutting condition A),
Work material: JIS / SS300 lengthwise equidistant four round grooved round bars,
Cutting speed: 310 m / min. ,
Incision: 2.5mm,
Feed: 0.4 mm / rev. ,
Dry intermittent cutting test of mild steel under the conditions (cutting condition B),
Work material: JIS-SMn433H, 4 longitudinally spaced round bars with equal intervals in the length direction,
Cutting speed: 320 m / min. ,
Incision: 2.5mm,
Feed: 0.35 mm / rev. ,
A dry intermittent cutting test of high-manganese steel under the above conditions (referred to as cutting condition C), and the flank wear width of the cutting edge in any cutting test is generally 0.3 mm, which is generally regarded as a guide for the service life of cutting tools. The cutting time up to was measured. The measurement results are shown in Table 10.

From the results shown in Tables 5 to 10, each of the coated cermet tools 1 to 13 of the present invention is between the Ti compound layer that is the lower layer of the hard coating layer and the modified α-type Al ₂ O ₃ layer that is the upper layer. The intervening reinforced α-type Al ₂ O ₃ layer shows the highest peak in the inclination angle section within the range of 75 to 90 degrees in the inclination angle number distribution graph of the (0001) plane, and this action makes the modified α type the Al ₂ O ₃ layer is sufficiently reinforced now with more excellent high temperature strength, furthermore, the rake face portion and flank portions including at least the cutting edge line portion of the reforming α type the Al ₂ O ₃ layer Combined with the fact that the surface is polished to a surface roughness of Ra: 0.2 μm or less and the effect of suppressing the progress of wear is exerted, especially in cutting of difficult-to-cut materials in which high cutting resistance is applied to the cutting edge, Chipping at the blade is remarkably suppressed, and excellent wear resistance is achieved for a long time. Whereas shown over, without intervening formation of the reinforcing α type the Al ₂ O ₃ layer to the hard coating layer, and conventional upper layer is constituted by a surface smoothness of less reformed α-type the Al ₂ O ₃ layer In the coated cermet tools 1 to 13, since the high temperature strength of the hard coating layer is insufficient in cutting difficult-to-cut materials, chipping is performed on the cutting edge portion together with the upper layer having low surface smoothness. It is clear that the service life is reached in a relatively short time.

  As described above, the coated cermet tool of the present invention is not only for cutting various general steels and ordinary cast iron, but also has a high viscosity, and the hard coating layer on the surface of the cutting tool at the time of cutting. Even when cutting difficult-to-cut materials such as mild steel, stainless steel, and high manganese steel, which have high cutting resistance, it has 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 cutting, and the cost reduction.

Is a schematic diagram illustrating a measurement range of the inclination angle in the case of measuring the crystal grains (0001) plane in the reinforcement α type the Al ₂ O ₃ layer constituting the hard layer of the present invention coated cermet tool. It is a schematic explanatory drawing which shows the measurement range of the inclination angle in the case of measuring the (0001) plane of the crystal grain in the modified α-type Al ₂ O ₃ layer constituting the hard coating layer. The inclination angle frequency distribution graph showing the tilt angle sections of 45 to 90 degrees to the present invention coated cermet reinforced α type constituting the hard layer of the tool 2 Al ₂ O ₃ layer. 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 hard layer of the present invention coated cermet tool 2.

Claims (1)

On the surface of the tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(1) The lower layer is composed of one or more of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer, and carbonitride layer, and a total average of 3 to 20 μm A Ti compound layer having a layer thickness,
(2) A hexagonal crystal lattice in which the upper layer has an α-type crystal structure in the state of chemical vapor deposition and exists within 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, 0 to 15 An inclination angle in which the highest peak exists in the inclination angle section within the range of degrees, and the total of the frequencies existing within the range of 0 to 15 degrees accounts for 50% or more of the entire degrees in the inclination angle frequency distribution graph Shows a number distribution graph and average layer thickness of 6-20 μm Modified α-type aluminum oxide layer having
In the surface-coated cermet cutting tool formed by vapor-depositing the hard coating layer composed of (1) and (2) above,
(A) Between the Ti compound layer as the lower layer and the modified α-type aluminum oxide layer as the upper layer, as a reinforcing layer, it has an α-type crystal structure in the same chemical vapor deposition state, and is a field emission type Using a scanning electron microscope, 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, and the normal to the polished surface is The tilt angle formed by the normal line of the (0001) plane, which is the crystal plane of the crystal grain, is measured, and the measured tilt angle within the range of 45 to 90 degrees out of the measured tilt angles is set every pitch of 0.25 degrees. In the slope angle distribution graph, which is divided and counts the frequencies existing in each section,
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. Reinforced 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,
Intervene,
(B) Furthermore, on the entire surface of the modified α-type aluminum oxide layer which is the upper layer of the hard coating layer,
Abrasive material having an overall average layer thickness of 0.4 to 5 μm, which is composed of two or more alternating layers of titanium nitride layers and titanium carbonitride layers having an average layer thickness of 0.1 to 2.5 μm. With the layer deposited,
In wet blasting, as a spraying abrasive, a polishing liquid containing 15 to 60% by mass of aluminum oxide fine particles in a proportion of the total amount with water is sprayed,
Modified α-type constituting the upper layer of the hard coating layer in the presence of the ground titanium nitride fine particles and ground titanium carbonitride fine particles by wet blasting of the abrasive layer and the aluminum oxide fine particles as the spray abrasive The rake face portion and the flank face portion including at least the cutting edge ridge line portion of the aluminum oxide layer are polished, and the surface roughness of these polished surfaces is measured based on the compliant standard JIS B0601-1994, Ra: 0.2 μm or less And
A surface-coated cermet cutting tool that exhibits excellent chipping resistance with a hard coating layer in cutting difficult-to-cut materials characterized by

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