JP2007216362A - Surface coated cermet-made cutting tool including 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-made cutting tool including a hard coating layer exhibiting excellent chipping resistance in cutting difficult-to-cut material. <P>SOLUTION: In this surface coated cermet-made cutting tool, the hard coating layer is formed on the surface of a tool base. The hard coating layer includes: a lower layer formed of Ti compound layer 3 to 20 μm; an inter-layer contact layer formed of a contact α-type Al<SB>2</SB>O<SB>3</SB>layer 0.1 to 1.9 μm; and an upper layer formed of a reformed α-type Al<SB>2</SB>O<SB>3</SB>layer 6 to 20 μm. The above upper layer and the inter-layer contact layer are formed of α-type Al<SB>2</SB>O<SB>3</SB>layer. 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 ranges of 30 to 45 degrees and 75 to 90 degrees, and the total of frequencies existing in the inclination angle sections occupies 50% or more of the whole frequency, and also 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 usually has an average layer thickness of 1 to 15 μm, an average layer thickness of 20 μm or less in a thickened state, and an aluminum oxide layer (hereinafter referred to as an α-type crystal structure in a state of chemical vapor deposition) , Conventionally α-type Al ₂ O ₃ layer)
A coated cermet tool formed by vapor-depositing the hard coating layer constituted by (a) and (b) above is known, and this coated cermet tool is used for cutting various general steels and ordinary cast irons, for example. It is well known that

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 use of FA for cutting machines has been remarkable. On the other hand, there has been a strong demand for labor saving and energy saving and further cost reduction for cutting work. There is a tendency to require a cutting tool having a cutting force, that is, a cutting tool capable of cutting as many kinds of work materials as possible with one kind of cutting tool. There is no problem when it is used for cutting ordinary steel such as steel and carbon steel, and ordinary cast iron such as gray cast iron, but this is especially useful for cutting difficult-to-cut materials such as mild steel, stainless steel, and high manganese steel. When used for, the difficult-to-cut material itself has a high viscosity and also has a high adhesiveness 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. What coupled with, it is assumed high cutting resistance, whereas the high temperature strength of the conventional α type the Al ₂ O ₃ layer constituting the hard coating layer is not sufficient to withstand this, chipping (fine result in cutting edge 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 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 was adjusted to a reaction gas composition different from the reaction gas composition under the above normal conditions, and the pressure was set to be relatively high compared to the reaction atmosphere pressure under the above normal conditions. When formed under the conditions, the resulting α-type Al ₂ O ₃ layer was polished in parallel with the tool base surface using a field emission scanning electron microscope, as shown in FIGS. A crystal grain having a hexagonal crystal lattice existing in the measurement range of the plane is irradiated with an electron beam, and the normal line of the (0001) plane that is the crystal plane of the crystal grain is normal to the normal plane of the polished plane Is measured, and the measured inclination angles within the range of 0 to 45 degrees out of the measured inclination angles are divided into pitches of 0.25 degrees, and the frequencies existing in each division are tabulated. Is shown in FIG. 3. As shown, a sharp maximum peak appears at a specific position in the tilt angle section, and according to the test results, at least one of the above-mentioned α-type Al ₂ O ₃ layer formation conditions, that is, the above reaction gas composition and reaction atmosphere conditions. If any of the conditions is changed within the above range, the position where the sharpest peak appears changes within the range of 30 to 45 degrees of the tilt angle section and exists within the range of 30 to 45 degrees. The total number of frequencies to occupy is 50% or more of the total frequency in the inclination angle frequency distribution graph, and the maximum peak of the inclination angle section is in the range of 30 to 45 degrees in the inclination angle frequency distribution graph as a result. The appearing α-type Al ₂ O ₃ layer (hereinafter referred to as a modified α-type Al ₂ O ₃ layer) has a higher high-temperature strength than the conventional α-type Al ₂ O ₃ layer formed under the above normal conditions. It must be a thing.

(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) 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 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.

(E) Therefore, the modified α type having the above excellent high temperature strength in a state where the upper layer has an average layer thickness of 6 to 20 μm equivalent to the layer thickness of the conventional α type Al ₂ O ₃ layer. The above-mentioned close contact α-type Al ₂ O ₃ layer, which is composed of an Al ₂ O ₃ layer and is extremely tightly bonded to both of the upper layer and the lower Ti compound layer, is 0.1 to 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 with an average layer thickness of 1.9 μm, and the surface roughness of these polished surfaces is increased. The coated cermet tool with Ra: 0.2 μm or less improves the high-temperature strength of the hard coating layer and improves the upper layer α even when cutting a difficult-to-cut material in which high cutting resistance is applied to the cutting edge. since the mold the Al ₂ O ₃ layer to mount an excellent surface smoothness, excellent resistance to Exhibits mappings properties, it exhibits a superior wear resistance over a long period.
The research results (a) to (e) have been obtained.

This invention was made based on the above research results, and on the surface of the tool base,
(1) As a lower layer, a Ti compound layer composed of 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,
(2) As an interlayer adhesion layer between the lower layer and the upper layer described below, a polished surface parallel to the tool base surface is obtained using a field emission scanning electron microscope having an α-type crystal structure in the state of chemical vapor deposition. 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;
(3) 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 base 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 angle number distribution graph and having an average layer thickness of 6 to 20 μm;
The hard coating layer composed of the above (1) to (3) is formed by vapor deposition,
Furthermore, on the entire surface of the modified α-type Al ₂ O ₃ layer, which 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, 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.
Further, if the average layer thickness is less than 6 μm, a sufficient service life cannot be secured for the cutting tool. On the other hand, if the average layer thickness exceeds 20 μm, chipping is likely to occur in cutting of difficult-to-cut materials. Therefore, the average layer thickness was determined to be 6 to 20 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.
Further, 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, this is chipping in cutting difficult-to-cut materials. The average layer thickness is determined to be 0.1 to 1.9 μm because it causes generation.

(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.

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. The contact 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 is extremely firmly adhered to both of them, and the modified By polishing the surface of the α-type Al ₂ O ₃ layer to a surface roughness of Ra: 0.2 μm or less, stainless steel, high-manganese steel, and even mild steel that have particularly high chip viscosity and are easily welded to the tool surface Even when cutting difficult-to-cut materials (work materials) such as the above, chipping of the hard coating layer is remarkably suppressed and wear is suppressed by the excellent high-temperature strength and smooth surface roughness of the hard coating layer. The effect is also demonstrated, and as a result, the long-term excellent resistance It will show wear properties.

  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,
The adhesion α-type Al ₂ O ₃ layer is formed by vapor deposition at the target layer thickness shown in Table 5 under the conditions
(C) Furthermore, reaction gas composition: volume%, AlCl ₃ : 6%, CO ₂ : 1.4%, HCl: 1%, SF ₆ : 0.09%, C ₂ H ₄ : 0.17, H ₂ : the rest,
Reaction atmosphere temperature: 1000 ° C.
Reaction atmosphere pressure: a predetermined pressure in the range of 20-30 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, 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,
Under the normal conditions, and with a target layer thickness as shown in Table 7, an interlayer adhesion layer is formed between the conventional α-type Al ₂ O ₃ layer and the lower Ti compound layer as shown in Table 7. Conventionally, coated cermet tools 1 to 13 were manufactured under the same conditions except that the formation of the abrasive layer and the surface polishing treatment by wet blasting were not performed.

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 8 and 9, respectively, the modified α-type Al ₂ O ₃ layers of the coated cermet tools 1 to 13 of the present invention. 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 8 and 9 also 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 a graph showing the distribution of the number of inclination angles of the modified α-type Al ₂ O ₃ layer (upper layer) of the coated cermet tool 2 according to the present invention, and FIG. 4 is a contact α-type Al ₂ O ₃ layer (interlayer adhesion) of the tool. 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 2, respectively. It is.

  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 above-described coated cermet tools 1 to 13 of the present invention and the various coated cermet tools 1 to 13 of the present invention, all of them are clamped and clamped to the tip of the tool steel tool by a bolt or a clamp piece. ,
Work material: JIS / SUS430 round bar,
Cutting speed: 330 m / min. ,
Cutting depth: 1mm,
Feed: 0.25 mm / rev. ,
Dry continuous cutting test of stainless steel under the conditions (cutting condition A),
Work material: JIS / SMn443H round bar,
Cutting speed: 290 m / min. ,
Cutting depth: 1mm,
Feed: 0.3 mm / rev. ,
Dry continuous cutting test of high manganese steel under the conditions (cutting condition B),
Work material: JIS / SS490, 4 longitudinally spaced round bars
Cutting speed: 300 m / min. ,
Cutting depth: 2mm,
Feed: 0.3 mm / rev. ,
A dry intermittent cutting test of mild steel under the above conditions (referred to as cutting condition C), and in any cutting test, the flank wear width of the cutting blade reaches 0.3 mm, which is generally regarded as a guide for the service life of cutting tools. The cutting time until was measured. The measurement results are shown in Table 10.

From the results shown in Tables 5 to 10, all of the coated cermet tools 1 to 13 of the present invention are (0001) plane inclination angle number distribution graphs, and the 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, the adhesive α-type Al ₂ O ₃ layer has excellent high temperature strength, while the adhesive α-type Al ₂ O ₃ layer exhibits excellent adhesion, and further includes a rake line including at least the cutting edge ridge portion of the modified α-type Al ₂ O ₃ layer. Surface roughness of the surface portion and the flank portion is Ra: 0.2 μm or less Combined with the fact that it is polished and the effect of suppressing the progress of wear is exerted, the chipping at the cutting edge is remarkably suppressed, especially in cutting of difficult-to-cut materials where high cutting resistance is applied to the cutting edge. While the wear resistance is shown over a long period of time, the upper layer of the hard coating layer has an unbiased distribution of measured inclination angles on the (0001) plane within the range of 0 to 45 degrees and 45 to 90 degrees. The conventional coated cermet tool which shows a gradient angle distribution graph in which the highest peak does not exist, is composed of a conventional α-type Al ₂ O ₃ layer with low surface smoothness, and has no intervening formation of the adhesive α-type Al ₂ O ₃ layer In Nos. 1 to 13, it is clear that chipping occurs in the hard coating layer when cutting difficult-to-cut materials due to insufficient strength of 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 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.

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 2. 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 2. 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 2. 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 2.

Claims (1)

On the surface of the tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(1) As a lower layer, it 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) As an interlayer adhesion layer between the lower layer and the upper layer described below, a polished surface parallel to the tool base surface is obtained using a field emission scanning electron microscope having an α-type crystal structure in the state of chemical vapor deposition. 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 aluminum oxide layer showing an inclination angle number distribution graph and having an average layer thickness of 0.1 to 1.9 μm;
(3) As an upper layer, a hexagonal crystal lattice having an α-type crystal structure in a chemical vapor deposited state and existing in a measurement range of a polished surface parallel to the tool base 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. A modified α-type aluminum oxide layer showing an inclination angle number distribution graph and having an average layer thickness of 6 to 20 μm;
The hard coating layer composed of the above (1) to (3) is deposited,
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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