JP3374599B2 - Hard wear-resistant composite coated cutting tool - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved hard sintered body cutting tool comprising a sintered body containing high-pressure phase boron nitride, particularly cubic boron nitride (hereinafter, CBN) as a main component. In particular, the present invention relates to a cutting tool having a composite coating formed of a hard wear resistant layer having excellent strength and wear resistance.

[0002]

2. Description of the Related Art High-pressure phase boron nitride is a material having the second highest hardness after diamond, and a sintered body of this high-pressure phase boron nitride has a low reactivity with a metal, so that a cutting tool for a metal, particularly an iron-based material, is used. Is used as. The high-pressure phase type boron nitride sintered body is made by sintering high-pressure phase type boron nitride particles at high temperature and high pressure using a binder (sintering aid), but it can be roughly classified into the following two types. it can. (1) Those containing 20 to 80% by volume of high-pressure phase type boron nitride crystal particles and using Ti carbide, nitride, or carbonitride as a sintering material (eg, JP-A-53-77811) (2) High pressure Contains 70% by volume of phase-type crystal grains and uses Al as a binder.
And those using Co metal (eg, Japanese Examined Patent Publication No. 52-43846)

These high-pressure phase boron nitride sintered bodies have hardness,
Since it is excellent in physical properties such as strength and thermal conductivity, it is used as a cutting tool for various steels. For example, type
The boron nitride sintered body of (1) has a Vickers hardness of 2,800 to 3,700.
It has excellent wear resistance and is used for cutting hardened steel. The high-pressure phase type boron nitride sintered body of type (2) has a Vickers hardness of 3,500 to 4,300 and is excellent in wear resistance and fracture resistance, so that it is used for cutting cast iron and high speed steel. However, due to the severer cutting conditions such as higher cutting speed and higher efficiency, it can be said that the above high-pressure phase boron nitride sintered body alone has sufficient heat resistance, wear resistance, and fracture resistance. The current situation is that they are gone.

In order to improve the wear resistance of the high-pressure phase boron nitride sintered body, a method of coating various wear-resistant layers such as TiN on the high-pressure phase boron nitride sintered body has been proposed (eg, special Kaisho
61-183187, JP-A-1-96083, JP-A 1-9
No. 6084, Japanese Patent Publication No. 2-44790), these known coated high-pressure phase boron nitride sintered body tools, the hardness of the wear-resistant layer,
Due to insufficient fracture resistance and crater abrasion resistance, cutting tools with a practically long service life have not yet been obtained. In particular, when cutting a hard-to-cut material such as hardened steel, lack of hardness, fracture resistance and crater wear resistance of the wear resistant layer is fatal, and the effect of improving wear resistance by coating does not appear. In addition, for cemented carbide, TiN, (Ti, Al) N, TiCN, A
A tool coated with l ₂ O ₃ or the like has also been proposed, but when the cutting temperature becomes high, the inside of the base material is significantly elastically plastically deformed, and easily peels or breaks.

[0005]

The object of the present invention is to obtain high hardness (several times of cemented carbide) and high strength of a high-pressure phase type boron nitride sintered body and excellent wear resistance of a hard wear resistant layer. When used in an ideal cutting tool that also has, for example, hardened steel cutting or cast iron rough cutting, the tool life is significantly longer than that of conventional tools, there is little variation in chipping, and a stable and durable hard tool is used. It is to provide a cutting tool having a composite coating including a wear layer.

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to a hard sintered body containing 20% by volume or more of high-pressure phase boron nitride, and in particular, a surface of a hard sintered body made of a CBN sintered body having excellent fracture resistance. 1) (Ti, Al) N layer, 2) has a structure in which a TiN layer and an AlN layer are repeatedly laminated, and has a cubic X-ray diffraction pattern as a whole, Superlattice laminated compound layer with a layer thickness of 0.2 nm to 20 nm (hereinafter, superlattice laminated compound layer of TiN and AlN) 3) At least two TiN layers and AlN layers are provided, and each layer has a grain size of 1 nm to Laminated film layer consisting of ultra-fine particles of 50 nm (hereinafter referred to as TiN
And at least one first hard wear-resistant layer selected from the group consisting of AlN ultrafine particle laminated film layers) and an Al ₂ O ₃ layer or A formed on the outer side thereof.
a _second multilayer film composed of two or more layers of l ₂ O ₃ and TiCN
A hard wear resistant layer composite coated cutting tool having a hard wear resistant layer.

FIG. 1 and FIG. 2 are conceptual cross-sectional views of various examples of cutting tools having a composite coating made of a hard wear-resistant layer according to the present invention, in which (1) is a hard sintered body base. 2 is a first hard wear-resistant layer, 3 is a second hard wear-resistant layer, and 4 and 5 are intermediate layers and surface layers which are provided as necessary.

The first and second hard wear resistant layers 2 and 3 can be formed by a PVD method such as an ion plating method or a CVD method such as a plasma CVD method. These methods are CB
While maintaining the wear resistance and fracture resistance of the N sintered body and the adhesion strength between the hard sintered body base material and the hard wear resistant layer at a high level,
It can be formed on a hard sintered body substrate.

Hard sintered body substrate (1) and hard wear resistant layer
Between (2) and (3), it is preferable to provide at least one intermediate layer 4 having a film thickness of 0.05 to 5 μm. The intermediate layer 4 is a nitride of a group 4a, 5a or 6a element of the periodic table,
It is preferably made of a material selected from the group consisting of carbides, oxides and solid solutions thereof, especially TiC, Ti
N, TiCN and TiCNO are preferred. Further, the surface layer 5 can be made of TiN, for example.

The hard wear resistant layer composite coated cutting tool of the present invention specifically means a tip, a drill, an end mill, etc., but is not particularly limited thereto. It has been confirmed that the hard wear resistant composite coating tool of the present invention has markedly improved cutting performance and tool life.

The tool according to the present invention can be preferably used, for example, in the following processing. Cutting of high hardness hard-to-cut materials such as carburized materials and die steels In this case, since the flank of the hard sintered body substrate (1) is dominated by mechanical wear, With (Ti, Al) N layer, TiN, which has excellent hardness and chipping resistance, which is effective in suppressing wear.
An ultrafine particle laminated film layer with AlN or a superlattice laminated compound layer with TiN and AlN is formed. On the other hand, the rake face of the hard sintered body has a large thermal wear rate, so that it suppresses crater wear. It is suitable to form an Al ₂ O ₃ layer having excellent effective thermal stability.

It is not preferable from the viewpoint of chipping resistance to coat the cutting flank of cast iron or mild steel with a single layer of Al ₂ O ₃ as the second hard wear-resistant layer. Since the static and dynamic stress loads on the hard wear-resistant layer during cutting are slight, Al ₂ O ₃ can be used on the flank face without defects. Therefore, when pursuing production efficiency, the flank may be covered with Al ₂ O ₃ . On the other hand, it is preferable to coat the rake face of the hard sintered body substrate in the same manner as.

Intermittent Cutting The flank of the hard sintered body base material is preferably coated with (Ti, Al) N, an ultrafine particle laminated film layer of TiN and AlN, or a superlattice laminated compound layer of TiN and AlN. In particular, the ultrafine particle laminated film layer of TiN and AlN has excellent chipping resistance because crack propagation can be suppressed at the interface by laminating nanometer-order fine particles to a thickness of the nonameter order. Is the best. On the other hand, the rake face of the hard sintered body substrate is liable to cause defects when the Al ₂ O ₃ layer is covered with a single layer like the one described above. Therefore, two or more layers of Al ₂ O ₃ and TiCN are laminated alternately. By coating with a film, it is possible to suppress the coarse grain structure of the hard wear-resistant layer and to combine the crater wear resistance and the fracture resistance.

That is, by changing the type and combination of hard wear resistant layers to be coated on the hard sintered body base material according to the type of work material, the optimum hard wear resistant layer composite coated cutting tool can be obtained. . The present invention has been made clear as a result of extensive research on various hard wear-resistant layers and various properties of high-pressure phase boron nitride sintered bodies. It is demonstrated by using it as a base material, and is based on an idea that is fundamentally different from the concept of the conventional coated cemented carbide tool.

[0015]

[Function] Generally, the hardness of the thin film is easily influenced by the base material,
The effect becomes more remarkable as the thickness of the thin film becomes thinner. In the present invention, among the existing substances, a high-pressure phase boron nitride sintered body (Hv = 2,800-
By using a hard sintered body substrate consisting of 5,000),
When the coating layer cannot follow the elasto-plastic deformation of the base material, which has been a big problem in the case of the coated cemented carbide tool using the conventional WC-based cemented carbide (Hv = 1,800) as the base material, It is possible to suppress peeling, and since the high-pressure phase boron nitride sintered body substrate exerts the effect of maintaining the high hardness of the hard wear-resistant layer even under high-temperature conditions during cutting, high-pressure phase boron nitride firing The wear resistance of the bound tool can be significantly improved.

In the present invention, the hard wear-resistant layer having excellent adhesion to the base material is formed by using the ion plating method or the plasma CVD method. The hardness of the hard wear-resistant layer is significantly increased due to the restraint at the interface with. That is, by using the high-pressure phase type boron nitride sintered body as the base material, the high hardness property of the hard wear resistant layer is further improved and excellent wear resistance is exhibited.

By coating a hard wear-resistant layer on at least the surface of a tool having a high-pressure phase type boron nitride sintered body as a base material, at least at a portion involved in cutting, high strength and high strength of the high-pressure phase type boron nitride sintered body can be obtained. The fracture resistance and the excellent wear resistance of the hard wear resistant layer are exposed to each other, and the wear resistance and the fracture resistance are remarkably improved, and as a result, the cutting performance and the tool life are significantly extended. In fact, the hard wear resistant layer composite coated cutting tool of the present invention has a longer service life than known ones, less variation due to chipping, and can be used stably.

The (Ti, Al) N used in the present invention can be produced by the method described in JP-A-2-194159. Ti
A superlattice laminated compound layer having a structure in which an N layer and an AlN layer are repeatedly laminated, having a cubic X-ray diffraction pattern as a whole, and each layer having a layer thickness of 0.2 nm to 20 nm −
It can be produced by the method described in Japanese Patent No. 3432. TiN layer
It has at least two AlN layers and each layer has a grain size of 1 nm to
An ultrafine particle laminated film of 50 nm can be produced by the method described in Japanese Patent Application No. 6-248503. Al ₂ O ₃ , TiC, TiN, TiCN
The layers of TiCNO and TiCNO can be produced in the usual way.

The hard wear-resistant layer has excellent properties such as hardness, oxidation resistance, chipping resistance, and resistance to work material. It has been found that the composite coating of the hard wear-resistant layer on the bonded body significantly improves the cutting performance, wear resistance, and fracture resistance as compared with the case where the hard wear-resistant layer is coated by a single layer.

When the total thickness of the hard wear resistant layer is less than 0.5 μm, the wear resistance is hardly improved. If the total thickness of the hard wear-resistant layer covering the flank exceeds 10 μm,
The characteristics due to the use of the hard sintered body substrate made of high-pressure phase boron nitride are lost, the mechanical characteristics of the hard wear-resistant layer itself become dominant, and the hard wear-resistant layer tends to be damaged. Further, the effect of residual stress in the hard wear-resistant layer becomes remarkable, cracks occur in the hard wear-resistant layer, the adhesion to the base material deteriorates, and peeling easily occurs. In the case of a hard wear-resistant layer coated on the rake face, thermal wear is dominant rather than mechanical wear unlike the case of the flank, so the total thickness of the hard wear-resistant layer should be within 15 μm. .

The intermediate layer serves to improve the adhesion between the hard wear-resistant layer and the base material, but in addition to this, there is an intermediate property between the hard wear-resistant layer and the base material having greatly different characteristics. By providing the intermediate layer, it is expected that the effect of reducing the residual stress of the film can be expected by controlling the change of the characteristics stepwise. Metal can be used as the intermediate layer in terms of relaxation of residual stress, but it has significantly lower hardness than the hard sintered body substrate and hard wear-resistant layer, and since it is rich in ductility and malleability, it promotes elasto-plastic deformation. , Causes deterioration of wear resistance. If the thickness of the intermediate layer is less than 0.05 μm, the adhesion is not improved, and conversely 5 μm.
Even if it exceeds m, no improvement in adhesion is observed. Therefore, from the viewpoint of characteristics and productivity, the thickness of the intermediate layer is 0.05 μm to 5 μm.
It is preferably in the range of m.

The thickness of the surface layer formed on the uppermost hard abrasion resistant layer is preferably 0.05 μm or more and 5 μm or less. This surface layer is provided for the purpose of determining the used corner, and is not intended to improve the wear resistance of the hard wear resistant layer composite coated cutting tool. If the thickness of this surface layer is less than 0.05 μm, it is difficult to determine the used corner, and if it exceeds 5 μm, it is not appropriate from the viewpoint of productivity.

The substrate can be selected from the above two types of high pressure type boron nitride sintered bodies. Preferred high-pressure phase type boron nitride sintered bodies are the following (1) and (2). (1) A CBN sintered body obtained by sintering 30 to 90% by volume of CBN powder and the rest of the binder powder at ultrahigh pressure (4 GPa or more).
The remaining binder powder is a binder composed of aluminum and at least one selected from the group consisting of nitrides, carbides, borides, oxides and solid solutions of the elements of Groups 4a, 5a and 6a of the Periodic Table. (And inevitable impurities). Among the CBN sintered bodies of this type (1), 50 to 95% by weight of TiC, TiN, TiCN, (TiM) is used as the binder powder.
At least one selected from the group consisting of C, (TiM) N and (TiM) CN (where M is a transition metal selected from the elements of groups 4a, 5a and 6a of the periodic table excluding Ti) ) And 5 to 50% by weight of aluminum and / or an aluminum compound (and inevitable impurities), a CBN sintered body is preferred because of improved wear resistance and strength.

(2) A sintered body obtained by ultra-high pressure sintering (4 GPa) of 40 to 95% by volume of CBN powder and the rest of the binder powder.
The remaining binder powder contains a binder (and inevitable impurities) composed of aluminum and / or an aluminum compound and at least one selected from the group consisting of TiN, Co, Ni, WC, TiC and solid solutions thereof. preferable. High-pressure phase type boron nitride sintered body obtained by high-pressure sintering (eg, US Pat. No. 4,110,184) at a pressure of 0.05 to 4 GPa using a hot pressing method, a HIP method, a plasma sintering method, a piston-cylinder device, etc. (1) The hard wear-resistant layer composite-coated cutting tool of the present invention, which is obtained by compound-coating the hard wear-resistant layer on the base material of (2) and (2), also exhibits excellent performance.

The type (1) CBN sintered body itself is known, and its characteristics and manufacturing method are described in detail in JP-A-53-7781. The type (2) CBN sintered body may be the binder described in Japanese Patent Publication No. 52-43846, to which TiN is added. By adding TiN, the adhesion with the hard wear resistant layer is improved.

In the CBN sintered body of type (1), the binder is selected from the group consisting of nitrides, carbides, borides, oxides of group 4a, 5a and 6a elements of the periodic table and solid solutions thereof. And at least one aluminum and / or aluminum compound in an amount of 5 to 50% by weight,
These react with CBN during sintering under high temperature and high pressure, and a compound such as aluminum boride (AlB ₂ ), aluminum nitride (AlN) is generated at the interface between the CBN particles and the binder, thereby binding between the particles. The strength is increased, and the hardness, toughness and strength of the sintered body are improved. In particular, when TiN and / or TiC is used as the binder, the z values of TiNz and TiCz are deviated from the stoichiometric ratio to obtain 0.5 ≦ z ≦ 0.85, respectively.
By increasing the amount of free titanium by setting 0.65 ≦ z ≦ 0.85, the reaction between CBN and the binder is promoted, and
A CBN sintered body having good wear characteristics and strength due to reaction products such as AlB ₂ , AlN and TiB ₂ can be obtained. Here, the z values of TiNz and TiCz are 0.5 ≦ z ≦ 0.85,
0.65 ≤ z ≤ 0.85 is defined as the z value of 0.5 and less than 0.65 makes the powder filling operation difficult due to the heat generated by the oxidation reaction, and when it exceeds 0.85, the reactivity between CBN and the binder is stoichiometric. This is because there is almost no difference from the case of using the theoretical ratio of TiN and TiC.

As a binder for a type (1) CBN sintered body
TiNz (0.5 ≦ z ≦ 0.85) and / or TiCz (0.65 ≦
z ≦ 0.85), aluminum and / or aluminum compound and C are contained when the amount of aluminum and / or aluminum compound in the binder is less than 5% by weight.
Since the reaction with BN is insufficient, the holding power of CBN by the binder becomes weak. On the contrary, if it exceeds 40% by weight, AlB ₂ , AlN,
Although the amount of reaction products such as TiB ₂ increases, the retention of CBN increases, but the relative content of CBN, which is superior to AlB ₂ and AlN in hardness and mechanical strength, decreases, and wear resistance significantly decreases. .

Therefore, conventionally, when a type (1) CBN sintered body is used as a cutting tool, the composition of the binder powder is 60 to 80% by weight of TiNz (0.5≤z≤0.85) and / or
Alternatively, TiCz (0.65 ≦ z ≦ 0.85) and 20 to 40% by weight of aluminum and / or an aluminum compound (and inevitable impurities) are considered to be optimal. However, in the composite high hardness material for tools of the present invention, by coating a hard wear resistant layer having excellent wear resistance, it is possible to impart excellent wear resistance to a CBN sintered body having poor wear resistance. The characteristics required for a CBN sintered body as a base material of a hard wear resistant layer composite coated cutting tool are higher strength than wear resistance, and high strength is an important factor.

That is, according to the present invention, by coating the hard wear-resistant layer according to the present invention, although it has sufficient toughness, it has a defect in wear resistance. A CBN sintered body using a binder containing a large amount of aluminum and / or an aluminum compound, which has not been used for cutting, can be an ideal hard wear resistant layer composite coated cutting tool having both fracture resistance and wear resistance. That is what made it clear.

In particular, in the type (1) CBN sintered body, the binder is 50 to 80% by weight of TiNz (0.5≤z≤0.85),
A hard wear resistant layer composite coated cutting tool consisting of 20 to 50% by weight of aluminum and / or aluminum compound (and unavoidable impurities) and having a transverse rupture strength (measured according to JIS standard) of 110 Kgf / mm ² or more. The effect becomes remarkable, and ordinary CBN sintered body tools and conventional wear resistant layer coated CB
It is possible to realize a tool life sufficiently satisfying a practical level even in the strong interrupted cutting of high hardness hardened steel, which could not be cut by the N sintered body tool.

TiNz (0.5 ≤ z ≤ 0.8) is used as the binder.
5) and / or TiCz (0.65 ≦ z ≦ 0.85), when the amount of aluminum and / or the aluminum compound exceeds 50% by weight, the hardness and strength of the CBN sintered body become insufficient, and the hard resistance of the present invention increases. It is not suitable as a base material for a wear layer composite coated cutting tool.

In the type (2) CBN sintered body, a CBN sintered body having a transverse rupture strength of 105 Kgf / mm ² or more can be manufactured by using CBN powder having an average particle size of 3 μm or less as a starting material. By coating this high toughness CBN sintered body substrate with the hard heat-resistant coating of the present invention, a high hardness which cannot be cut by a normal CBN sintered body tool or a conventional wear resistant layer-coated CBN sintered body tool. It is possible to realize a tool life sufficiently satisfying a practical level even in the strong interrupted cutting of hardened steel.

[0033]

EXAMPLES Examples of the present invention will be described below. However, the following examples are illustrative of the present invention and the present invention is not limited to the following examples.

Example 1 A binder powder was obtained by mixing a binder having TiN _0.7 and Al in a ratio of 80:20 (weight ratio) using a cemented carbide pot and a ball. Next, the binder and CBN powder were mixed in a volume ratio of 40:60, filled in a Mo container, and sintered at a pressure of 5.2 GPa and a temperature of 1,750 K for 15 minutes. The transverse rupture strength of the obtained sintered body measured by the method described in JIS standard is 1
It was 05 Kgf / mm ² .

SNGN 120408 type chips were made from this sintered body.
(ISO standard), covered with TiCN of the intermediate layer by the ion plating method, and then with (Ti, Al) N, TiN
A superlattice laminated compound of AlN and an ultrafine particle laminated film of TiN and AlN are respectively formed, and Al _{2 is formed} by a plasma CVD method.
A multilayer film in which two or more layers of O ₃ or Al ₂ O ₃ and TiCNO were laminated was coated, and finally, a surface layer made of TiCNO was coated by 5 μm by the plasma CVD method. In the case of covering only the rake face, the flank face was covered with a mask thin plate made of molybdenum, and the film was formed with only the rake face exposed or adjusted by polishing.

The evaluation is made of a hardened steel with hardness HRC63 (SUJ2
Material) round bar, cutting speed 150m / min, depth of cut 0.2
Dry cutting was performed at m, feed of 0.1 mm / revolution, and flank wear amount of each chip, crater wear amount, and time to fracture were measured 25 minutes after the start of cutting. The layer thickness of each hard wear-resistant layer is the same as the fracture surface of the hard wear-resistant layer composite coated cutting tool.
It was observed by EM and measured. The flank wear amount was measured using a stereoscopic microscope. The amount of crater wear was measured using a laser microscope and a surface roughness meter. For comparison, a CBN sintered body cutting tool not coated with a hard wear resistant layer,
A hard wear resistant layer-coated cutting tool in which the hard wear resistant layer was coated with a single layer was also measured. The results are shown in [Table 1] to [Table 3].

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

The following can be understood from the results of [Table 1] to [Table 3]. 1) In cutting hardened steel (SUJ2 material), the hard wear resistant layer composite coated cutting tool according to the present invention is superior to the conventional CBN sintered body tool and the cutting tool coated with a single hard wear resistant layer. It shows wear resistance. 2) The flank is coated with (Ti, Al) N, a superlattice laminated compound layer of TiN and AlN or an ultrafine particle laminated film layer of TiN and AlN, and the rake face is covered with an Al ₂ O ₃ layer or Al ₂ O ₃ The hard wear resistant layer composite cutting tool according to the present invention, which is coated with a multilayer film in which two or more layers of TiCN and TiCN are laminated, is excellent. 3) The hard wear resistant layer composite cutting tools of sample numbers 7, 8, 11 to 13, 16, 17, 22 to 27 are excellent.

4) From Sample Nos. 15 to 18, it was found that no improvement in wear resistance was observed when the total thickness of the hard wear-resistant layer coated on the rake face was less than 0.5 μm, and peeling occurred when it exceeded 15 μm. The total thickness of the hard wear-resistant layer coated on the flank is 0.5μ
It can be seen that when the thickness is less than m, no improvement in wear resistance is observed, and when the thickness exceeds 10 μm, peeling occurs. Therefore, the total thickness of the hard wear-resistant layer is suitably 0.5 to 15 μm for the rake face and 0.5 to 10 μm for the flank face. 5) From Sample Nos. 9 to 14, it can be seen that when the thickness of the intermediate layer is less than 0.03 μm, the effect of improving the adhesive strength is not observed, and conversely, when it exceeds 5 μm, the adhesiveness is not improved.

Example 2 Using various hard wear resistant layer composite coated cutting tools similar to those in Example 1, the outer circumference of the FC300 material round bar with hardness HB170 was cut at a cutting speed of 500 m / min, a cut of 0.25 mm and a feed of 0.15 mm /. Dry cutting was performed by rotation, and the flank wear amount and crater wear amount when the cutting distance of each chip was 10 km were measured. In addition, the cutting distance at the time of reaching the defect was measured. For comparison, the same measurement was carried out on a CBN sintered body tool not coated with a hard wear resistant layer. The results are shown in [Table 4].

[0043]

[Table 4]

From the results of [Table 4], cast iron (FC300 material)
It is understood that, in the cutting of No. 3, the hard wear resistant layer composite coated cutting tool according to the present invention exhibits better wear resistance than the conventional CBN sintered body tool and the cutting tool having the hard wear resistant layer as a single layer. In addition, as in Example 1, the flank (Ti, Al)
N, TiN and AlN superlattice laminated compound layer or TiN and Al
An ultrafine particle laminated film layer with N is coated, and Al ₂ O ₃ is applied to the rake face.
It can be seen that the hard wear-resistant layer composite cutting tool of the present invention coated with a layer or a multilayer film in which two or more layers of Al ₂ O ₃ and TiCN are laminated is excellent (Sample Nos. 1 to 3). In addition, Example 1
Unlike the cutting of the hardened steel of No. 2, in the cutting of the cast iron used in Example 2, even if the flank face was coated with a single layer of Al ₂ O ₃ as the second hard wear-resistant layer, there was no loss or peeling. , It was revealed that it could be sufficiently utilized (Sample No. 1).

Example 3 Binder powder in which the ratio of Co, Al, WC and TiN was set to the ratio of 43: 30: 25: 2 (weight ratio) was mixed using a cemented carbide pot and ball, and binder powder was prepared. Got This binder and CBN
The powder and the powder were mixed in a volume ratio of 12:88, filled in a Mo container, and sintered at a pressure of 5.2 GPa and a temperature of 1750 K for 15 minutes. The bending strength of the obtained sintered body was 100 Kgf / mm ² .
(Measured by the method described in JIS standard). SN this sintered body
A GN120408 (ISO standard) type chip was processed, and a (Ti, Al) N, a superlattice laminated compound of TiN and AlN or an ultrafine particle laminated body of TiN and AlN was formed into a film by an ion plating method. After that, by plasma CVD method, Al ₂ O ₃ or Al
A multilayer film in which two or more layers of ₂ O ₃ and TiCN were laminated was coated. 2.5 μm for each sample by the ion plating method.
m of TiN layer is deposited and plasma CVD method is used.
A surface layer of a TiCN layer having a thickness of μm was formed.

Using each hard wear-resistant coated cutting tool, the hardness H was carburized and quenched with V-shaped grooves at 6 locations on the outer circumference.
Cutting speed of 150m / min around the outer circumference of RC60 SCM-415 material,
Dry cutting was performed with a depth of cut of 0.2 mm and a feed of 0.1 mm / revolution, and the flank wear amount and crater wear amount of each hard wear resistant layer-coated cutting tool at the time of impact of 50,000 times were measured. Further, the number of impacts until each hard wear resistant layer-coated cutting tool was damaged was measured. For comparison, the same measurement was performed on a CBN sintered body cutting tool without coating of a hard wear resistant layer (CBN sintered body base material used for a hard wear resistant layer composite coated cutting tool). The results are shown in [Table 5] and [Table 6].

[0047]

[Table 5]

[0048]

[Table 6]

From the results of [Table 5] and [Table 6], the carburized material (S
In the intermittent cutting of CM-415 material, the hard wear resistant layer composite coated cutting tool according to the present invention has significantly better wear resistance than the conventional CBN sintered body tool and the cutting tool coated with a single hard wear resistant layer. You can see that Also, on the flank (T
i, Al) N, superlattice laminated compound of TiN and AlN, TiN and A
coated with an ultrafine particle laminate of 1N and Al ₂ O ₃ on the rake face
A hard wear-resistant layer composite cutting tool (Sample Nos. 13 to 15) which is coated with a multilayer film in which two or more layers of TiCN and TiCN are alternately laminated to suppress coarse-grained grain structure is excellent. Wear resistant composite cutting tools are excellent.

Example 4 The same substrate as in Example 2 was coated with an intermediate layer of TiN to a thickness of 2.5 μm by the ion plating method, and then each hard wear resistant layer was subjected to the ion plating method and / or plasma CV.
A hard wear resistant layer composite coated cutting tool coated by the D method was manufactured. Using the tool obtained, FCD550 with hardness HB160
Wet cutting the outer periphery of the black skin material (automotive parts) at a cutting speed of 250 m / min, a depth of cut of 2 mm, and a feed of 0.25 mm / revolution, and the number of passes until the hard wear-resistant layer composite coated cutting tool is damaged (one work material) Per one cutting) was measured. For comparison, the same measurement was performed on a CBN sintered body cutting tool not coated with a hard wear resistant layer (CBN sintered body base material for a hard wear resistant layer composite coated cutting tool). The results are shown in [Table 7].

[0051]

[Table 7]

From the results of [Table 7], in rough cutting of FCD550 black skin material, the hard wear resistant layer composite coated cutting tool of the present invention is more effective than the conventional CBN tool or the hard wear resistant layer coated single layer cutting tool. It can be seen that also shows extremely excellent wear resistance.
In particular, a hard wear resistant composite cutting tool with a flank face coated with a superlattice laminate compound of TiN and AlN and a rake face coated with a multilayer film in which two or more layers of Al ₂ O ₃ and TiCN are alternately laminated (sample The number 6) is excellent.

Example 5 A cutting tool having a composite hard wear-resistant layer similar to the sample 26 of Example 1 was prepared, but the CBN sintered body of the base material had the CBN content (volume%) shown in [Table 8]. And the binder composition (wt%). Cutting speed using SKD11 of hardness HRC60 having four U-shaped grooves on the outer periphery as the work material 1
Dry cutting was carried out at 50 m / min, incision 0.15 mm, and feed 0.1 mm / revolution, and the defect rate (number of samples: 5) after cutting for 5 minutes was measured. The results are shown in [Table 8] and [Table 9].

[0054]

[Table 8]

[0055]

[Table 9]

Similar to the hard wear resistant layer composite coated cutting tools of Examples 1 to 4, this embodiment is also significantly more remarkable than the conventional CBN sintered body tool and the cutting tool coated with the hard wear resistant layer as a single layer. It can be seen that it shows excellent wear resistance, but [Table 8]
The results of [Table 9] further indicate that a high-strength, high-toughness base material was developed as a dedicated base material for a hard wear resistant layer composite cutting tool,
A hard wear-resistant layer which is further excellent in fracture resistance and wear resistance and can be stably used over a long life (with little variation with respect to fracture) by compositely coating the hard wear-resistant layer according to the present invention It reveals that a composite coated cutting tool can be developed.

[0057]

As described above, the hard wear resistant layer composite coated cutting tool of the present invention is a high pressure type boron nitride sintered body substrate having excellent strength, hardness and fracture resistance, particularly a CBN sintered body substrate. By coating a hard wear resistant layer with excellent wear resistance with good adhesion, it has both fracture resistance and wear resistance, has a significantly longer life than conventional cutting tools, and is applicable to a wide range of applications. It has possible cutting performance.

[Brief description of drawings]

FIG. 1 is a conceptual cross-sectional view of an example of a cutting tool having a composite coating of a hard wear resistant layer of the present invention.

FIG. 2 is a conceptual cross-sectional view of another embodiment of the cutting tool of the present invention.

[Reference code]

1 Hard Sintered Body Substrate 2 First Hard Wear-Resistant Layer 3 Second Hard Wear-Resistant Layer 4 Intermediate Layer 5 Surface Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-24606 (JP, A) JP-A-5-337703 (JP, A) JP-A-7-3432 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B23B 27/14 C04B 35/583 C23C 14/06

Claims (10)

(57) [Claims] 1. A 1) (Ti, Al) N layer, and 2) a TiN layer are provided at a location related to cutting of the surface of a hard sintered body substrate (1) containing 20 vol% or more of high-pressure phase type boron nitride. Superlattice compound layer having a structure in which an AlN layer is repeatedly laminated and having a cubic X-ray diffraction pattern as a whole, and the layer thickness of each layer is 0.2 nm to 20 nm, 3) TiN layer and AlN And at least two layers, each layer consisting of ultrafine particles having a particle size of 1 nm to 50 nm, and each layer having a thickness of 1 nm to
First hard wear-resistant coating layer selected from the group consisting of laminated film layers having a thickness of 60 nm
(2) and has an Al ₂ O ₃ layer or an Al ₂ O ₃ layer on at least a part of the outside.
A hard wear-resistant layer composite-coated cutting tool having a second hard wear-resistant coating layer (3) comprising a multilayer film in which two or more layers of O ₃ and TiCN are laminated. 2. The first hard wear-resistant coating layer (2) and the second hard portion are the portions involved in the cutting of the portion corresponding to the rake face of the hard sintered body substrate containing 20 vol% or more of high-pressure phase type boron nitride. The hard wear resistant layer composite coated cutting tool according to claim 1, wherein the hard wear resistant layer composite coated cutting tool has a wear resistant coating layer (3), and a portion corresponding to a flank has only the first hard wear resistant coating layer (2). 3. A film thickness of 0.05 to 5 μm on at least a part of an interface between a hard sintered body substrate (1) containing 20 vol% or more of high-pressure phase type boron nitride and a hard wear resistant layer (2: 3). TiN, TiC, TiC
The hard wear resistant layer composite coated cutting tool according to claim 1 or 2, further comprising an intermediate layer (4) made of at least one selected from the group consisting of N and TiCNO. 4. At least one selected from the group consisting of 0.1 μm to 5 μm of TiC, TiN, TiCN and TiCNO on at least part of the outer surface of the hard wear resistant layer (2: 3).
A hard wear resistant layer composite coated cutting tool according to any one of claims 1 to 3 having a seed surface layer (5). 5. A hard sintered body substrate (1) containing high-pressure phase type boron nitride in an amount of 20% by volume or more, comprising a cubic type boron nitride powder and / or wurtzite type boron nitride in an amount of 30 to 90% by volume and the balance of It is a sintered body substrate obtained by high-pressure sintering with a binder powder, wherein the binder powder is a nitride, a carbide, a boride, an oxide of a group 4a, 5a, or 6a element of the periodic table, and a solid solution thereof. A hard wear resistant layer composite coated tool according to any one of claims 1 to 4, which is composed of at least one selected from the group consisting of and aluminum and / or an aluminum compound (and inevitable impurities). . 6. The high-pressure phase type boron nitride is cubic boron nitride, and the binder powder is 50 to 95% by weight of TiC and / or Ti.
N and / or TiCN and / or TiCNO and / or (TiM) C and / or (TiM) N and /
Or at least one selected from the group consisting of (TiM) CN and / or (TiM) CNO (where M is
Is a transition metal selected from elements of groups 4a, 5a and 6a of the periodic table excluding Ti) and 5 to 50% by weight of aluminum and / or an aluminum compound.
A hard wear layer composite coated cutting tool according to. 7. TiNz (0.
5 ≤ z ≤ 0.85), 20 to 50% by weight of aluminum and / or aluminum compound, and unavoidable impurities, and the bending strength (measured by JIS standard) is 110 Kgf / mm ²
The hard wear resistant layer composite coated cutting tool according to claim 6, which is the above. 8. A TiCz (0.
65 ≦ z ≦ 0.85), 20 to 50% by weight of aluminum and / or aluminum compound, and unavoidable impurities, and the transverse rupture strength (measured by JIS standard) is 105 Kgf / mm ²
The hard wear resistant layer composite coated cutting tool according to claim 6, which is the above. 9. A hard sintered body substrate (1) containing high-pressure phase type boron nitride in an amount of 20% by volume or more comprises a cubic boron nitride powder and / or a wurtzite type boron nitride 45 to 95% by volume and a binder powder. Is a sintered compact base material obtained by high-pressure sintering of
5. At least one selected from the group consisting of Co, Ni, WC, TiN, TiC and solid solutions thereof, and aluminum and / or an aluminum compound (and inevitable impurities). A hard wear resistant layer composite coated tool according to item. 10. The hard according to claim 9, wherein the high-pressure phase type boron nitride is cubic type boron nitride, the average particle size is 3 μm or less, and the transverse rupture strength (measured according to JIS standard) is 105 Kgf / mm ² or more. Wear resistant layer composite coated tool.