JP4844872B2 - Method for manufacturing a cutting throwaway tip made of surface-coated cermet that exhibits excellent chipping resistance with a hard coating layer in high-speed cutting of difficult-to-cut materials - Google Patents

Description

This invention is particularly difficult to cut, that is, the cutting of relatively high-viscosity and soft work materials such as stainless steel, high-manganese steel, and soft steel is accompanied by high heat generation. As a result, the work material In addition, the surface-coated cermet cutting throwaway tip (hereinafter referred to as the coated cutting tip) exhibits excellent chipping resistance even when performed under high-speed cutting conditions where the chip adhesion is further increased. It is related with the manufacturing method .

Conventionally, generally, for example, as illustrated in a schematic perspective view in FIG. 13, a tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet is used, and the center portion. A cermet base (hereinafter referred to collectively as a chip base) having a tool mounting bolt through hole (in the case where the mounting is performed by clamping with a clamp piece, the bolt through hole does not exist). ) On the entire rake face and flank face including the cutting edge ridge
(A -1 ) Ti carbide (hereinafter referred to as TiC) layer, nitride (hereinafter also referred to as TiN) layer, carbonitride (hereinafter referred to as TiCN), all formed by chemical vapor deposition as the lower layer ) Layer, carbon oxide (hereinafter referred to as TiCO) layer, and carbonitride oxide (hereinafter referred to as TiCNO) layer, and has an overall average layer thickness of 3 to 20 μm. Ti compound layer,
(A -2 ) As an upper layer, it has an average layer thickness of 1 to 15 μm, and an α-type crystal structure in the state of chemical vapor deposition,
Composition _{formula: (Al 1-Z Cr Z} ) 2 O 3, ( provided that an atomic ratio, Z: 0.01 to 0.1),
A composite oxide layer of Al and Cr satisfying the following (hereinafter simply referred to as a composite oxide layer),
A coated cutting tip formed by vapor-depositing a hard coating layer composed of ( a-1 ) and ( a-2 ) is known, and this coated cutting tip is, for example, continuous cutting of various types of steel and cast iron. In addition, the surface of the composite oxide layer that constitutes the upper layer of the hard coating layer may be subjected to a wet blast treatment for the purpose of improving the cutting performance and smoothed as necessary. Are known.

In general, in the above-mentioned coated cutting tip, 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 improved in strength of the layer itself. For the purpose of the above, it is formed by chemical vapor deposition at a medium temperature range of 700 to 950 ° C. using a mixed gas containing organic carbonitride as a reaction gas in a normal chemical vapor deposition apparatus, and has a vertically grown crystal structure It is also known to do so.
JP 52-66508 A Japanese Patent Laid-Open No. 6-8010

  In recent years, the performance of cutting equipment has been remarkable. On the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting, and along with this, cutting tends to be faster. In the cutting tip, there is no problem if this is used to cut work materials such as ordinary steel such as carbon steel and low alloy steel and ordinary cast iron such as gray cast iron under normal conditions. In particular, the work material has a relatively high viscosity, and cutting of difficult-to-cut materials such as soft stainless steel, high manganese steel, and even mild steel is accompanied by high heat generation, which further increases the adhesion resistance due to the work material. When performed under high-speed conditions that increase, since the hard coating layer does not have sufficient high-temperature strength, chipping (slight chipping) is likely to occur in the hard coating layer, resulting in a relatively short time. Used in The leads to life at present.

Therefore, the present inventors conducted research to improve the chipping resistance of the hard coating layer of the coated cutting tip from the above viewpoint,
(A-1) A composite oxide layer (hereinafter referred to as a conventional composite oxide layer) as an upper layer constituting the hard coating layer of the conventional coated cutting tip is, for example, a normal chemical vapor deposition apparatus.
Reaction gas composition: by _{volume%, AlCl 3: 2.3~4%,} CrCl 3: 0.04~0.26%, CO 2: 6~8%, HCl: 1.5~3%, H 2 S : 0.05~0.2%, H _2: remainder,
Reaction atmosphere temperature: 1020 to 1050 ° C.
Reaction atmosphere pressure: 6 to 10 kPa,
(Hereinafter referred to as normal conditions), but prior to the formation of the conventional composite oxide layer,
Reaction gas composition: by _{volume%, AlCl 3: 2.3~4%,} CrCl 3: 0.04~0.26%, CO 2: 6~8%, HCl: 1.5~3%, H 2 S : 0.05~0.2%, H _2: remainder,
Reaction atmosphere temperature: 750 to 900 ° C.
Reaction atmosphere pressure: 6 to 10 kPa,
On the surface of the Ti compound layer as the lower layer under the conditions
Composition _{formula: (Al 1-Z Cr Z} ) 2 O 3, ( provided that an atomic ratio, Z: 0.01 to 0.1),
A composite oxide nucleus of Al and Cr that satisfies the following conditions (hereinafter simply referred to as a composite oxide nucleus) is formed. In this case, the composite oxide nucleus has an average layer thickness of 20 to 200 nm (0.02 to 0.2 μm). The composite oxide core thin film is desirable, and subsequently, the mixed oxide core thin film is heated under a condition that the heating atmosphere is changed to a hydrogen atmosphere at a pressure of 3 to 13 kPa and the heating atmosphere temperature is increased to 1100 to 1200 ° C. As the upper layer of the hard coating layer with the heat treatment applied to the same conditions as the above normal conditions, that is,
Reaction gas composition: by _{volume%, AlCl 3: 2.3~4%,} CrCl 3: 0.04~0.26%, CO 2: 6~8%, HCl: 1.5~3%, H 2 S : 0.05~0.2%, H _2: remainder,
Reaction atmosphere temperature: 1020 to 1050 ° C.
Reaction atmosphere pressure: 6 to 10 kPa,
In the condition of
Also the composition _{formula: (Al 1-Z Cr Z} ) 2 O 3, ( provided that an atomic ratio, Z: 0.01 to 0.1),
When the composite oxide layer satisfying the above is formed, the resulting composite oxide layer deposited on the composite oxide core thin film (hereinafter referred to as a modified composite oxide layer) is α-type in the state of chemical vapor deposition. In addition, the high-temperature strength is further improved as compared with the conventional composite oxide layer, and the effect of improving the chipping resistance of the hard coating layer is exhibited.

(A-2) The modified complex oxide layer has the same crystal structure of the corundum hexagonal close-packed crystal as the above-described conventional complex oxide layer, that is, constituent atoms composed of Al, Cr, and oxygen exist at lattice points. Consist of crystal grains having a corundum type hexagonal close-packed crystal structure.

(A-3) About the conventional composite oxide layer constituting the upper layer of the hard coating layer of the conventional coated cutting tip and the modified composite oxide layer of (a-1),
Using a field emission scanning electron microscope, as shown in the schematic explanatory diagrams in FIGS. 1A and 1B, an electron beam is individually applied to each crystal grain having a hexagonal crystal lattice existing within the measurement range of the surface polished surface. Irradiation is performed to measure the inclination angle formed by the normal line of the (0001) plane that is the crystal plane of the crystal grain with respect to the normal line of the surface-polished surface. When the measured inclination angle within the range is divided for each pitch of 0.25 degrees and the inclination angle number distribution graph is formed by counting the frequencies existing in each division, the conventional composite oxide layer is As illustrated in FIG. 3, the distribution of measured inclination angles on the (0001) plane shows an unbiased inclination angle number distribution graph in the range of 0 to 45 degrees, whereas the modified composite oxide layer has As shown in FIG. 2, a sharp peak appears in the range of 0 to 10 degrees. To exhibit an oblique angle frequency distribution graph.

(A-4) When forming the modified composite oxide layer, the Cr content ratio in the layer and the average layer thickness of the heat-treated composite oxide core thin film were 1 to 10 atomic% and 20 to 200 nm, respectively, as described above. By doing this, the above sharp maximum peak in the inclination angle frequency distribution graph appears within the range of 0 to 10 degrees of the inclination angle section, and the total of the frequencies existing within the range of 0 to 10 degrees (this frequency total) And the height of the highest peak are proportional to each other), but the inclination angle number distribution graph occupies a ratio of 45% or more of the entire frequency in the inclination angle number distribution graph, and accordingly, the Cr content ratio in the layer If any of the average layer thicknesses of the heat-treated composite oxide core thin film deviates from the above range, the ratio of the tilt angle number in the range of 0 to 10 degrees in the tilt angle number distribution graph is less than 45%. There will be impossible to obtain desired high-temperature strength enhancing effect.

(B-1) The smoothness of the deposition surface of the modified composite oxide layer and the conventional composite oxide layer constituting the upper layer of the hard coating layer in the above-mentioned coated cutting tip is not fully satisfactory, and the above-mentioned deposition 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 sprayed on the surface by wet blasting as a spray abrasive to the total amount with water. When polished, both of the composite oxide layers are measured based on the compliant standard JIS B0601-1994 (the following surface roughness is all measured based on the compliant standard), and Ra: 0 When the smoothed surface of the composite oxide layer as a result has a surface roughness of Ra: 0.3 to 0.6 μm, a hard coating layer is obtained. Has a significant effect on improving chipping resistance. Never.

(B-2) On the other hand, as illustrated in a schematic perspective view in FIG. 11, on the entire rake face and flank face including the cutting edge ridge line portion of the modified composite oxide layer constituting the upper layer of the hard coating layer,
(B-2-1) First, as a lower layer, the reaction gas composition is in volume%,
TiCl ₄ : 0.2 to 10%,
CO ₂ : 0.1 to 10%,
Ar: 5 to 60%,
H ₂ : Remaining
And
Reaction atmosphere temperature: 800-1100 ° C.
Reaction atmosphere pressure: 4 to 70 kPa (30 to 525 torr),
And having an average layer thickness of 0.1 to 3 μm and a ratio of oxygen to Ti of 1.25 to 1.90 as measured by an Auger spectrometer,
Composition formula: TiO _W ,
In the case of
W: 1.25 to 1.90 in atomic ratio,
Forming a titanium oxide layer that satisfies
(B-2-2) Next, on the titanium oxide layer (lower layer), as an upper layer, the normal conditions, that is, the reaction gas composition in volume%,
TiCl ₄ : 0.2 to 10%,
N ₂ : 4-60%,
H ₂ : Remaining
And
Reaction atmosphere temperature: 800-1100 ° C.
Reaction atmosphere pressure: 4 to 90 kPa (30 to 675 torr),
When a TiN layer having an average layer thickness of 0.05 to 2 μm is formed under the conditions described above,
(B-2-3) At the time of forming the TiN layer (upper layer), oxygen in the titanium oxide layer constituting the lower layer diffuses and the upper layer (TiN layer) is constituted by a titanium oxynitride layer. However, in this case, the titanium oxide layer, which is the lower layer after the formation of the upper layer (the titanium oxynitride layer), has a ratio of oxygen measured by an Auger spectrometer at the center in the thickness direction. 1.2 to 1.7 atomic ratio to Ti,
Composition formula: TiO _x ,
In the case of
X: 1.2 to 1.7 in atomic ratio,
Titanium oxide layer that satisfies
(B-2-4) In addition, the upper layer composed of the titanium oxynitride layer was also measured at the center in the thickness direction with an Auger spectroscopic analyzer, and the ratio of diffused oxygen was the atomic ratio with respect to nitrogen (N). 0.01-0.4, i.e.
Composition formula: TiN _1-Y (O) _Y ,
(Where, (O) represents diffused oxygen from the titanium oxide layer as the lower layer when the upper layer is deposited ),
Y: 0.01 to 0.4 in atomic ratio
Titanium nitride oxide layer that satisfies

(B-3) With the titanium nitride oxide layer (upper layer) and the titanium oxide layer (lower layer) deposited and formed,
When a polishing liquid containing 15 to 60% by mass of Al ₂ O ₃ fine particles as a spraying abrasive in a ratio to the total amount of water is sprayed by wet blasting as in (b-1) above, the nitrogen The titanium oxide layer and the titanium oxide layer are pulverized and pulverized by the Al ₂ O ₃ fine particles, become titanium oxynitride fine particles and titanium oxide fine particles, and act as an abrasive in the presence of the Al ₂ O ₃ fine particles. As illustrated in the schematic perspective view, the surface of the modified composite oxide layer constituting the upper layer of the hard coating layer is polished, and as a result, the surface of the modified composite oxide layer after polishing is Ra. When the surface of the modified composite oxide layer is smoothed to a surface roughness of Ra: 0.2 μm or less, the surface of the hard coating layer is smoothed to a surface roughness of 0.2 μm or less. A significant improvement in chipping resistance appears To become.

(C-1) On the other hand, the hard coating layer is formed by being deposited on the surface of the chip substrate at a reaction temperature of about 1000 ° C. and cooled to room temperature by a chemical vapor deposition apparatus. In the process, since the thermal expansion coefficient of the hard coating layer is relatively larger than the thermal expansion coefficient of the chip substrate, tensile stress remains in the hard coating layer. Residual tensile stress in the layer acts to promote chipping in high-speed cutting.

(C-2) On the other hand, a single basic shape mark, for example, a single basic shape mark such as a circle, a triangle and a quadrangle, or a similar shape thereof, is used for either the rake face or the flank face of the coated cutting tip. As shown in a schematic perspective view of an embodiment in which the single basic shape mark is circular, for example, in FIGS. 4 to 10 using a laser beam over the entire surface of both surfaces, the single basic Either or both of the shape mark and the collective mark of the single basic shape mark are distributed (in this case, the examples shown in FIGS. 4 to 6 have a relatively thin hard coating layer, 8 and FIGS. 9 and 10 show the distribution mode when the layer thickness increases, and the single basic shape mark is exposed to any one of the constituent layers of the hard coating layer. Digging surface (In this case, the depth of the exposed surface of the single basic shape mark is individually adjusted in accordance with the layer thickness of the hard coating layer. When a laser beam irradiation pattern is formed at a depth corresponding to 5 to 20%), the residual stress of the hard coating layer is remarkably reduced. By the formation of the hard coating layer residual stress reduction pattern, In particular, the occurrence of chipping of the hard coating layer during high-speed cutting of difficult-to-cut materials is significantly suppressed.

(D) The modified composite oxide layer constituting the upper layer of the hard coating layer has a high temperature hardness and heat resistance that the composite oxide layer itself has, in addition to the conventional composite oxide layer. The surface of the modified composite oxide layer, which has higher high-temperature strength and is the upper layer of the hard coating layer, is smoothed to a surface roughness of Ra: 0.2 μm or less, and the residual stress of the hard coating layer is reduced. Since the chipping resistance of the hard coating layer is remarkably improved by the formation of the pattern, the coated cutting tip formed by vapor-depositing the hard coating layer having such a structure is capable of cutting difficult-to-cut materials by generating high heat. Even under high-speed conditions where the adhesion resistance is even higher, chipping does not occur in the hard coating layer, and excellent cutting performance will be exhibited over a long period of time.
The research results shown in (a) to (d) above were obtained.

This invention was made based on the above research results,
(1) On the entire surface of the rake face and the flank face including the cutting edge ridge line portion of the chip base composed of the WC base cemented carbide or TiCN base cermet,
(A -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 an overall average layer thickness of 3 to 20 μm ,
(A -2 ) As an upper layer, it has an average layer thickness of 1 to 15 μm, and
Composition _{formula: (Al 1-Z Cr Z} ) 2 O 3, ( provided that an atomic ratio, Z: 0.01 to 0.1),
And using a field emission scanning electron microscope, each crystal grain having a hexagonal crystal lattice existing within the measurement range of the surface polished surface is irradiated with an electron beam, and the normal to the surface polished surface is Then, the inclination angle formed by the normal line of the (0001) plane, which is the crystal plane of the crystal grain, is measured, and the measurement inclination angle within the range of 0 to 45 degrees out of the measurement inclination angles is 0.25 degrees. In the inclination angle number distribution graph formed by dividing each pitch and the frequency existing in each section, the highest peak exists in the inclination angle section within the range of 0 to 10 degrees, and the 0 to 10 degrees. A modified composite oxide layer showing a tilt angle number distribution graph in which the total number of frequencies existing in the range of 45% or more of the total frequency in the tilt angle number distribution graph,
The hard coating layer composed of ( a-1 ) and ( a-2 ) is formed by chemical vapor deposition,
(2) Next , on the entire surface of the modified composite oxide layer, which is the upper layer of the hard coating layer,
(B-1) The lower layer has an average layer thickness of 0.1 to 3 μm, and
Composition formula: TiO _x ,
, Measure the central part in the thickness direction with an Auger spectrometer,
X: 1.2 to 1.7 in atomic ratio,
Satisfying titanium oxide layer,
(B-2) The upper layer has an average layer thickness of 0.05 to 2 μm, and
Composition formula: TiN _1-Y (O) _Y ,
(However, (O) indicates the diffused oxygen from the Ti oxide layer, which is the lower layer when the upper layer is deposited ), and the central portion in the thickness direction is also measured with an Auger spectrometer. And
Y: 0.01 to 0.4 in atomic ratio
Satisfying titanium oxynitride layer,
In the state where the abrasive layer composed of (b-1) and (b-2) is formed by chemical vapor deposition,
( 3 ) 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,
Abrasive layer and the Al ₂ O ₃ by atomization of injection formed by grinding atomized pulverized titanium oxide fine pre pulverization oxynitride titanium particulate is injected abrasive above, coexistence of Al ₂ O ₃ fine as injection abrasive The rake face portion and the flank face portion including at least the cutting edge ridge line portion of the modified composite oxide layer constituting the upper layer of the hard coating layer are polished, and the surface roughness of these polished surfaces is set to Ra: 0. .2 μm or less,
( 4 ) Further, any one of the rake face and flank face of the polished surface of the modified composite oxide layer , or any of the single basic shape mark and the collective mark of the single basic shape mark over the entire surface of both surfaces. Or a hard covering layer residual stress reduction pattern in which the single basic shape mark is a dug-down surface in which any one of the constituent layers of the hard coating layer is exposed. Formed by beam irradiation,
The hard coating layer is characterized by a method of manufacturing a coated cutting tip that exhibits excellent wear resistance in high-speed cutting.

The reason why the hard coating layer, the abrasive material layer , and the Al ₂ O ₃ fine particles of the polishing liquid used in the wet blasting in the manufacturing method of the coated cutting chip of the present invention are numerically limited as described above will be described below.
( 1 ) Hard coating layer (a-1) Ti compound layer of lower layer The Ti compound layer itself has high-temperature strength, and the presence of the Ti compound layer makes the hard coating layer have high-temperature strength. And the modified composite oxide layer that is the upper layer firmly adhere to each other, and thus has an effect of improving the adhesion of the hard coating layer to the chip substrate, but when the total average layer thickness is less than 3 μm, If the total average layer thickness exceeds 20 μm, the high-speed cutting with high heat generation is likely to cause thermoplastic deformation, which causes uneven wear. Therefore, the total average layer thickness was determined to be 3 to 20 μm.

(A-2) Modified composite oxide layer of the upper layer In the modified composite oxide layer, Al as a constituent component thereof improves the high-temperature hardness and heat resistance of the layer, As described above, in the coexistence with the Cr component in the heat-treated composite oxide core thin film, the frequency distribution ratio existing in the range of 0 to 10 degrees in the inclination angle frequency distribution graph is increased, and this is extremely high at 45% or more. The distribution ratio has the effect of improving the high-temperature strength of the layer. In this case, if the Z value indicating the Cr content ratio is less than 0.01 by atomic ratio, the desired improvement effect cannot be ensured for the above-described action. On the other hand, if the Z value exceeds 0.1, the distribution ratio of the frequencies existing within the range of 0 to 10 degrees in the inclination angle frequency distribution graph becomes less than 45%, making it difficult to ensure the desired high-temperature strength. Therefore, the Z value is determined to be 0.01 to 0.1 It was.
In addition, as described above, the average layer thickness of the heat-treated composite oxide core thin film also affects the frequency distribution ratio existing in the range of 0 to 10 degrees in the gradient angle distribution graph of the modified composite oxide layer. If the average layer thickness is less than 20 nm, the distribution ratio of the frequencies existing within the range of 0 to 10 degrees in the inclination angle distribution graph cannot be made 45% or more, and as a result, the desired excellent high-temperature strength cannot be obtained. On the other hand, even if the average layer thickness exceeds 200 nm, the distribution ratio of the frequencies existing in the range of 0 to 10 degrees is less than 45%. Therefore, the average layer thickness is preferably 20 to 200 nm. .
Further, the modified composite oxide layer has excellent high temperature strength and heat resistance in addition to the excellent high temperature hardness and heat resistance of the composite oxide layer itself as described above, but the average layer thickness is less than 1 μm. If the above properties of the modified composite oxide layer are not sufficiently provided in the hard coating layer, on the other hand, if the average layer thickness exceeds 15 μm, thermoplastic deformation that causes uneven wear tends to occur. Since the wear is accelerated, the average layer thickness is determined to be 1 to 15 μm.

(B) Abrasive material layer As described above, the titanium oxynitride layer constituting the upper layer first forms a titanium oxide layer in which the oxygen ratio is 1.25 to 1.90 (W value) in terms of atomic ratio to Ti. Then, it is formed by depositing a TiN layer on the titanium oxide layer under normal conditions. Therefore, diffusion of oxygen from the titanium oxide layer during the formation of the TiN layer is indispensable. When the W value of the titanium oxide layer is less than 1.25, the diffusion reaction of oxygen into the TiN layer is drastically reduced, and the ratio of diffused oxygen (Y value) in the upper layer is 0.01 by atomic ratio. On the other hand, if the same W value exceeds 1.90, the ratio of diffused oxygen (Y value) in the upper layer will increase beyond 0.40 in terms of atomic ratio. The value is defined as 1.25 to 1.90 In this case, the oxygen ratio (X value) in the lower layer (titanium oxide layer) after forming the upper layer takes a value in the range of 1.2 to 1.7 in terms of atomic ratio, in other words, the upper layer. When the X value of the lower layer after formation satisfies 1.2 to 1.7, the Y value of the upper layer satisfies 0.01 to 0.40.
In this case, the X value of the lower layer and the Y value of the upper layer are set to 1.2 to 1.7 and 0.01 to 0.40, respectively. It is obtained from many test results that these abrasive layers are pulverized and atomized in a suitable state at the time of wet blasting, and exhibit an excellent polishing function sufficiently. Based on this. Therefore, if the X value and Y value are out of the range of 1.2 to 1.7 and 0.01 to 0.40, respectively, the pulverization and atomization at the time of wet blasting of the abrasive layer is not satisfactorily performed, which is excellent. The polishing function cannot be expected.
Further, the average layer thicknesses of the upper layer and the lower layer were set to 0.05 to 2 μm and 0.1 to 3 μm, respectively, when the average layer thickness was less than 0.05 μm and less than 0.1 μm. The ratio of the pulverized titanium oxide fine particles in the lower layer and the fine pulverized titanium oxynitride fine particles in the upper layer is too small to perform the polishing function sufficiently, while the average layer thickness is 2 μm and 3 μm, respectively. Even if it exceeds the range, the polishing function will rapidly decrease, and in any case, the surface of the composite oxide layer cannot be polished to a surface roughness of Ra: 0.2 μm or less. is there.

(C) The Al ₂ O ₃ fine of Al ₂ O ₃ fine fraction polishing liquid of the polishing liquid, pulverization oxynitride of pulverized titanium oxide fine and the upper layer of the lower layer of the abrasive layer during wet blasting Although it acts to polish the surface of the modified composite oxide layer in the state of coexisting with the titanium fine particles, even if the ratio is less than 15% by mass or more than 60% by mass in the total amount with water Since the polishing function is abruptly lowered, the ratio was determined to be 15 to 60% by mass.

In the coated cutting tip manufactured by the method of the present invention, the modified composite oxide layer constituting the upper layer of the hard coating layer has a conventional composite oxide in addition to the high temperature hardness and heat resistance of the composite oxide layer itself. The rake face portion and the flank face portion including at least the cutting edge ridge line portion of the modified composite oxide layer, which has a higher high-temperature strength than the oxide layer, and is an upper layer of the hard coating layer, are represented by Ra. : Hard coating layer residual stress reduction pattern formed by laser beam irradiation over the entire surface of either the rake face or the flank face or both of the polished face while being polished to a surface roughness of 0.2 μm or less Can significantly improve the chipping resistance of hard coatings, especially for high-viscosity cutting of soft, difficult-to-cut materials with relatively high viscosity such as stainless steel, high manganese steel, and mild steel. Case as well, without chipping in the hard coating layer, exhibits superior cutting performance over a long period of time, and makes it possible to further life extension of service life.

Next, the method for producing a coated cutting tip according to the present invention will be specifically described with reference to examples.

WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder, and Co powder all having an average particle diameter of 1 to 3 μm are prepared as raw material powders. These raw material powders were blended into the composition shown in Table 1, added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and pressed into a green compact with a predetermined shape at a pressure of 98 MPa. The green compact was vacuum sintered at a predetermined temperature in the range of 1370 to 1470 ° C. for 1 hour in a vacuum of 5 Pa. After sintering, the cutting edge portion was R: 0.07 mm honing By processing, chip bases A to F made of WC-based cemented carbide having a throwaway tip shape defined in ISO · CNMG12041 were manufactured.

In addition, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder, all having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and pressed into a compact at a pressure of 98 MPa. The green compact was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1540 ° C. for 1 hour, and after the sintering, the cutting edge portion was subjected to a honing process of R: 0.07 mm. TiCN base cermet chip bases a to f having a standard / CNMG12041 chip shape were formed.

Next, each of these chip bases A to F and chip 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. The Ti compound layer is deposited as a lower layer of the hard coating layer with the combinations and target layer thicknesses shown in Table 8 under the conditions shown in Table 4). After the composite oxide core thin film [shown as a core thin film in Tables 4 and 8] (a) to (h) is formed by vapor deposition with the combinations and target layer thicknesses shown in Table 8, the composite oxide core thin film is formed. Pressure: in a hydrogen atmosphere of 8 kPa, heat treatment was performed at 1150 ° C. under the condition of holding for a predetermined time within a range of 10 to 60 minutes, and in this state, combinations and targets shown in Table 8 under the same conditions as shown in Table 4 Modified composite oxide layer by layer thickness [Table 4, In shown in the reforming layer] The (A) ~ (H) is deposited formed as an upper layer of the hard coating layer,
(B) Next, a titanium oxide layer [TiO _W (1) to (6), which is a lower layer of the abrasive layer, is formed on the entire surface of the modified composite oxide layer constituting the upper layer of the hard coating layer. ] Is formed under the conditions shown in Table 6, and a titanium nitride layer (TiN layer), which is the upper layer, is vapor-deposited with the target layer thickness shown in Table 9 under the conditions shown in Table 6 as well. 9 is measured by an Auger spectroscopic analyzer to form an abrasive layer composed of a lower layer and an upper layer of the X value and the Y value shown in Table 9 (FIG. 9). 11),
(C) Subsequently, the coated cutting tip for forming the abrasive layer composed of the lower layer and the upper layer is subjected to wet blasting under the blasting conditions shown in Table 7 and in the combinations shown in Table 9, The rake face portion and the flank face portion including the cutting edge ridge line portion of the modified composite oxide layer were polished to the surface roughness shown in Table 7 in the state where the abrasive layer was present around the attachment hole. (See FIG. 12),
(D) Furthermore, using a laser beam irradiation apparatus, the hard coating layer for polishing the modified composite oxide layer surface,
Laser beam output: 10W
The shape of a single basic shape mark: a circle with a diameter of 0.8 mm,
Hard coating layer residual stress reduction pattern: any one of the implementation patterns shown in FIGS. 4 to 10 is applied in the combination shown in Table 9.
Depth of digging on the exposed surface of a single basic shape mark: the depth shown in Table 9 as a percentage of the total target layer thickness of the hard coating layer,
The coated cutting chips 1 to 13 of the present invention were manufactured by forming a hard coating layer residual stress reduction pattern under the conditions described above.

(A) For comparison purposes, as shown in Table 10, the Ti compound layer was formed by vapor deposition under the same conditions as the lower layers of the coated cutting chips 1 to 13 of the present invention, and further the conditions shown in Table 5 Then, a conventional composite oxide layer [shown as a conventional layer in Tables 5 and 10] as an upper layer is formed by vapor deposition with the combinations and target layer thicknesses shown in Table 10 (see FIG. 13).
(B) Subsequently, the cutting edge ridge line of the conventional composite oxide layer is formed by performing wet blasting under the blasting conditions shown in Table 7 and the combinations shown in Table 10 without forming the abrasive layer. The rake face and the flank face including the portion were polished to the same surface roughness as shown in Table 10, while the conventional coated cutting chips 1 to 13 were produced without forming the hard coating layer residual stress reducing pattern.

Next, field emission scanning is performed on each of the modified composite oxide layer and the conventional composite oxide layer constituting the upper layer of the hard coating layer of the present invention coated cutting chips 1 to 13 and the conventional coated cutting chips 1 to 13. An inclination angle number distribution graph was created using an electron microscope.
That is, the inclination angle number distribution graph is set in a lens barrel of a field emission scanning electron microscope in a state where the surfaces of the modified composite oxide layer and the conventional composite oxide layer are polished surfaces. Electron backscattering is performed by individually irradiating a crystal grain having a hexagonal crystal lattice existing within the measurement range of the surface-polished surface with an electron beam of 15 kV and an acceleration voltage of 15 kV on the surface with an irradiation current of 1 nA. Using a diffraction image apparatus, a 30 × 50 μm region at an interval of 0.1 μm / step is inclined with respect to the normal of the surface polished surface and the normal of the (0001) plane that is the crystal plane of the crystal grain An angle is measured, and based on this measurement result, among the measured inclination angles, a measurement inclination angle within a range of 0 to 45 degrees is divided for each pitch of 0.25 degrees and exists in each division. Created by counting the frequencies.

  In the gradient angle distribution graphs of the various modified complex oxide layers and the conventional complex oxide layers obtained as a result, the gradient angle segment in which the (0001) plane shows the highest peak, and the gradient within the range of 0 to 10 degrees. Tables 8 and 10 show the ratios of the number of tilt angles existing in the angle section to the number of tilt angles in the entire tilt angle distribution graph, respectively.

In the various inclination angle distribution graphs described above, as shown in Tables 8 and 10, each of the modified composite oxide layers of the coated cutting tip of the present invention has a measured inclination angle distribution of (0001) plane of 0 to 0. An inclination angle number distribution graph in which the highest peak appears in the inclination angle section within the range of 10 degrees and the ratio of the inclination angle numbers existing in the inclination angle section within the range of 0 to 10 degrees is 45% or more is shown. On the other hand, in the conventional composite oxide layer of the conventional coated cutting tip, the distribution of the measured inclination angle on the (0001) plane is unbiased within the range of 0 to 45 degrees, and the highest peak does not exist. The inclination angle number distribution graph in which the ratio of the inclination angle number existing in the inclination angle section within the range of 10 degrees is 30% or less was also shown.
FIG. 2 is a graph showing the inclination angle distribution of the modified composite oxide layer of the coated cutting tip 4 of the present invention, and FIG. 3 is a graph showing the inclination angle distribution of the conventional composite oxide layer of the conventional coated cutting tip 4. Is.

  Further, for the above-described coated cutting chips 1 to 13 of the present invention and the conventional coated cutting chips 1 to 13, the constituent layers of the hard coating layer were observed using an electron beam microanalyzer (EPMA) and an Auger spectroscopic analysis device (layer When the longitudinal section was observed), it was confirmed that the former consisted of a Ti compound layer and a modified composite oxide layer having substantially the same composition as the target composition. On the other hand, it was confirmed that both of the latter consisted of a Ti compound layer having the same composition as the target composition and a conventional composite oxide layer. Moreover, when the thickness of the constituent layer of the hard coating layer of these coated cutting tips was measured using a scanning electron microscope (same longitudinal section measurement), the average layer thickness (which is substantially the same as the target layer thickness) Average value of 5-point measurement) was shown.

Next, for the various coated cutting chips of the present invention coated cutting chips 1 to 13 and the conventional coated cutting chips 1 to 13 described above, all of them are screwed to the tip of the tool steel tool with a fixing jig,
Work material: JIS / SS400 round bar,
Cutting speed: 390 m / min,
Incision: 2.5mm,
Feed: 0.3mm / rev,
Dry high-speed continuous cutting test (normal cutting speed is 280 m / min) of mild steel under the following conditions (referred to as cutting condition A),
Work material: JIS / SUS405 lengthwise equidistant four round grooved round bars,
Cutting speed: 320 m / min,
Incision: 1.5mm,
Feed: 0.25mm / rev,
In a dry high-speed intermittent cutting test (normal cutting speed is 170 m / min) of stainless steel under the conditions (referred to as cutting condition B),
Work material: JIS · SCMnH1 lengthwise equidistant four round grooved round bars,
Cutting speed: 240 m / min,
Cutting depth: 2mm,
Feed: 0.2mm / rev,
The dry high-speed intermittent cutting test (normal cutting speed is 120 m / min) of high-manganese steel under the above conditions (referred to as cutting condition C). The cutting time until reaching 0.3 mm, which is regarded as a standard for the service life, was measured. The measurement results are shown in Table 11.

From the results shown in Tables 8 to 11, the coated cutting tips 1 to 13 of the present invention manufactured by the method of the present invention have the upper layer of the hard coating layer divided into the inclination angle sections within the range of 0 to 10 degrees. A modified composite oxidation showing a slope angle distribution graph in which the highest peak is present and the sum of the frequencies within the range of 0 to 10 degrees occupies 45% or more of the whole frequency in the slope angle distribution graph In addition to the excellent high temperature hardness and heat resistance of the modified composite oxide layer, the modified composite oxide layer has a further superior high temperature strength, and at least a cut of the modified composite oxide layer. The hard coating layer residual stress reducing pattern in which the rake face portion and the flank portion including the edge line portion are polished to a surface roughness of Ra: 0.2 μm or less, and the entire polished surface is irradiated with a laser beam. By Combined with the significant reduction in residual tensile stress in the hard coating layer, the cutting resistance of difficult-to-cut materials such as stainless steel, high manganese steel, and mild steel will be further increased by high heat generation. Even when performed under high speed conditions, the hard coating layer exhibits excellent cutting performance over a long period without occurrence of chipping, whereas the upper layer of the hard coating layer is within the range of 0 to 10 degrees. It is composed of a conventional composite oxide layer showing an inclination angle distribution graph in which the frequency distribution ratio is 30% or less, and the surface roughness of the conventional composite oxide layer is Ra: 0.3 to 0.6 μm. In the conventional coated cutting chips 1 to 13 in which the hard coating layer residual stress reduction pattern is not formed, chipping occurs in the hard coating layer in the above-described high-speed cutting of the difficult-to-cut material, which is relatively short. Useful life in time It is clear that lead to.

As described above, the coated cutting tip manufactured by the method of the present invention is not only difficult to perform high-speed cutting such as various low alloy steels and general steels such as carbon steel, and ordinary cast iron such as gray cast iron. Even when used for high-speed cutting of cutting materials, it exhibits excellent chipping resistance and exhibits excellent cutting performance over a long period of time. It can cope with energy saving and cost reduction sufficiently satisfactorily.

It is a schematic explanatory drawing which shows the measurement range of the inclination angle of the (0001) plane of the crystal grain in the complex oxide layer which comprises a hard coating layer. It is an inclination angle number distribution graph of the modified complex oxide layer constituting the hard coating layer of the present invention coated cutting tip 4. 4 is a graph showing the distribution of the number of inclination angles of a conventional composite oxide layer constituting a hard coating layer of a conventional coated cutting tip 4. It is a schematic perspective view which shows the Example of the hard coating layer residual stress reduction pattern formed by laser beam irradiation in this invention cutting chip manufactured by the method of this invention . It is a schematic perspective view which shows Examples other than FIG. 4 of the hard coating layer residual stress reduction pattern formed by laser beam irradiation in this invention cutting chip manufactured by the method of this invention . It is a schematic perspective view which shows Examples other than FIG.4, 5 of the hard coating layer residual stress reduction pattern formed by laser beam irradiation in this invention cutting chip manufactured by the method of this invention . It is a schematic perspective view which shows Examples other than FIGS. 4-6 of the hard coating layer residual stress reduction pattern formed by laser beam irradiation in this invention cutting chip manufactured by the method of this invention . It is a schematic perspective view which shows Examples other than FIGS. 4-7 of the hard coating layer residual stress reduction pattern formed by laser beam irradiation in this invention cutting chip manufactured by the method of this invention . It is a schematic perspective view which shows Examples other than FIGS. 4-8 of the hard coating layer residual stress reduction pattern formed by laser beam irradiation in this invention cutting chip manufactured by the method of this invention . It is a schematic perspective view which shows Examples other than FIGS. 4-9 of the hard coating layer residual stress reduction pattern formed by laser beam irradiation in this invention cutting chip manufactured by the method of this invention . It is the schematic perspective view which cut and showed a part of said abrasive | polishing material layer for the covering cutting chip after the abrasive | polishing material layer vapor deposition formation in the method of this invention . It is the schematic perspective view which showed the coated cutting chip after the wet blasting in the method of this invention by notching a part of hard coating layer . It is the general | schematic perspective view which notched and showed a part of hard coating layer the conventional coated cutting chip .

Claims (1)

( 1 ) On the entire rake face and flank face including the cutting edge ridge line portion of the cermet base composed of tungsten carbide base cemented carbide or titanium carbonitride base cermet,
(A -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 3 to 20 μm. A Ti compound layer having an overall average layer thickness,
(A -2 ) As an upper layer, it has an average layer thickness of 1 to 15 μm, and an α-type crystal structure in the state of chemical vapor deposition,
Composition _{formula: (Al 1-Z Cr Z} ) 2 O 3, ( provided that an atomic ratio, Z: 0.01 to 0.1),
And using a field emission scanning electron microscope, each crystal grain having a hexagonal crystal lattice existing within the measurement range of the surface polished surface is irradiated with an electron beam, and the normal to the surface polished surface is Then, the inclination angle formed by the normal line of the (0001) plane, which is the crystal plane of the crystal grain, is measured, and the measurement inclination angle within the range of 0 to 45 degrees out of the measurement inclination angles is 0.25 degrees. In the inclination angle number distribution graph formed by dividing each pitch and the frequency existing in each section, the highest peak exists in the inclination angle section within the range of 0 to 10 degrees, and the 0 to 10 degrees. A modified composite oxide layer of Al and Cr showing a tilt angle number distribution graph in which the total number of frequencies existing in the range occupies a ratio of 45% or more of the whole frequency in the tilt angle frequency distribution graph,
The hard coating layer composed of ( a-1 ) and ( a-2 ) is formed by chemical vapor deposition,
( 2 ) Next , on the entire surface of the modified composite oxide layer, which is the upper layer of the hard coating layer,
( B-1 ) The lower layer has an average layer thickness of 0.1 to 3 μm, and
Composition formula: TiO _x ,
, The central part in the thickness direction is measured with an Auger spectrometer, and the atomic ratio is
X: 1.2 to 1.7,
Satisfying titanium oxide layer,
(B-2) The upper layer has an average layer thickness of 0.05 to 2 μm, and
Composition formula: TiN _1-Y (O) _Y ,
(However, (O) indicates the diffused oxygen from the titanium oxide layer, which is the lower layer when the upper layer is formed by vapor deposition ). Similarly, the central portion in the thickness direction is measured with an Auger spectrometer. , Also in atomic ratio,
Y: 0.01 to 0.4
Satisfying titanium oxynitride layer,
In the state where the abrasive layer composed of (b-1) and (b-2) is formed by chemical vapor deposition,
( 3 ) In wet blasting, 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 as a spray abrasive.
In the coexistence of pulverized titanium oxide fine particles and pulverized titanium oxynitride fine particles obtained by pulverizing and atomizing the above-mentioned abrasive layer by spraying aluminum oxide fine particles that are spray abrasives, and the aluminum oxide fine particles as spray abrasives, The rake face portion and the flank face portion including at least the cutting edge ridge line portion of the modified composite oxide layer constituting the upper layer of the hard coating layer are polished, and the surface roughness of these polished surfaces is determined according to JIS / B0601-1994. Ra: 0.2 μm or less in the measurement based on
( 4 ) Further, any one of the rake face and flank face of the polished surface of the modified composite oxide layer, or any of the single basic shape mark and the collective mark of the single basic shape mark over the entire surface of both surfaces. Or a hard covering layer residual stress reduction pattern in which the single basic shape mark is a dug-down surface in which any one of the constituent layers of the hard coating layer is exposed. Forming beam irradiation,
A method for producing a surface-coated cermet cutting throwaway tip that exhibits excellent chipping resistance in a high-speed cutting of difficult-to-cut materials characterized by

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