JPH0742489B2 - Abrasion resistant parts with tool or hard head made of composite sintered material - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a composite sintered material having a hard head.

More specifically, the present invention relates to a small cross section having a hard head such as a diamond sintered body or a high-pressure phase boron nitride sintered body, and a supporting portion made of cemented carbide integrally formed with the head. Of the composite sintered material.

The composite sintered material having a small cross section, which is the subject of the present invention, can be used as a material for a high-performance small-diameter drill or a head portion of a dot printer.

2. Description of the Related Art Drills made of cemented carbide are widely used for drilling metal and non-metal materials. In particular, cemented carbide drills with a diameter of about 1 mm or thinner are used for drilling printed circuit boards, which are in rapid demand in recent years. It is expected that the degree of integration of printed circuit boards will increase in the future, and the use rate of smaller diameter drills will increase accordingly.

On the other hand, various materials are used for printed circuit boards,
Mainly used is a reinforced resin obtained by impregnating glass fiber with an epoxy resin, which is generally called a glass epoxy substrate.

Drilling of such a printed circuit board is usually performed with a high-rigidity drill at a rotational speed of 50,000 to 60,000 rpm, but the glass fiber contained in the circuit board causes the cemented carbide tool to wear very quickly, and generally With 3000 to 5000 hits (hits are the number of holes drilled), a carbide drill reaches its end of life. These drill machines are equipped with an automatic tool changer, which automatically replaces the drill when it reaches the end of its useful life. However, as the degree of integration of printed circuit boards increases as described above, the time for this automatic tool change is also a problem in order to improve production efficiency.
There is a strong demand to extend the drill life and reduce the number of tool changes, that is, the change time.

Considering the characteristics of printed circuit boards, there is a strong demand for further improvement in heat resistance and other functions, and such board materials can be actually manufactured, but in general, such high-performance materials are difficult to manufacture. Due to grinding, the life of conventional ultra-hard drills becomes extremely short, and it is the actual situation that this kind of substrate material cannot be put to practical use.

Furthermore, it is desired to increase the rotation speed of the drill to make even more efficient drilling for ordinary glass-epoxy substrates, but this is also the case with conventional cemented carbide drills, where the life is sharply increased with increasing cutting speed. However, it is impossible to achieve high efficiency by increasing the rotation speed of the drill.

On the other hand, sintered diamond tools, whose usage has been increasing rapidly in recent years, have dramatically higher hardness than cemented carbide tools and have excellent wear resistance, which makes them extremely useful in cutting such reinforced resins. Demonstrate high performance.

However, as shown in FIG. 1, the sintered diamond material currently on the market has a shape in which a sintered diamond layer 11 is bonded to a support portion 12 of cemented carbide at 14 portions.

When a drill is produced using this composite sintered body 13, the composite sintered body 13 is attached to the tip of the shank 15 as shown in FIG.
There is no choice but to fix it by some method.

However, for example, the diameter of the drill used for printed circuit boards is generally smaller than about 1 mm, and in some cases it is about 0.1 mm. Joined part by cutting edge grinding
It deviates from 16, and a good drill cannot be manufactured.
In particular, sintered diamond is difficult to grind, has a high grinding resistance, and is insufficient in strength at the level of ordinary silver brazing.
Electron beam welding, for example, is considered as a joining method with high joining strength, but if electron beam welding is implemented, the manufacturing process of the drill will be complicated and the cost will be high, and it will be possible to respond to the recent rapid increase in demand for high-performance drills. There wasn't.

On the other hand, when the support portion is described, the strength of the support portion is very important especially in the case of a product having a small diameter. As described above, the degree of integration of printed circuit boards has been increasing in recent years, and it can be considered that this phenomenon will accelerate in the future. That is, the diameter of the through-hole plated hole is gradually reduced. In the future, the amount of drills with small diameters of 0.1 mmφ or 0.3 mmφ will increase in the production of printed circuit boards. At this time, a particular problem is breakage of the drill, and if it breaks before the end of its life due to wear of the cutting edge, there is no point in using an expensive sintered diamond drill. If the support portion is made of a soft material or a material having low rigidity to avoid breakage, there is a problem that the support portion is easily bent and there is no straight hole. There is also a problem of wear of the supporting portion due to cutting chips.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention aims to solve the above-mentioned problems of the prior art, and more specifically, a small-diameter composite having a hard head and a support having high strength and transverse rupture strength. An object of the present invention is to provide a sintered material, which enables easy production of a drill or the like having excellent machinability, wear resistance and rigidity and having a long life.

A further object of the present invention is to provide a long-life drill at a low price, which enables easy and high-performance drilling of a difficult-to-cut substrate such as a glass epoxy substrate.

A further object of the present invention is to provide a small-diameter composite sintered material as an intermediate product that can easily manufacture an elongated member such as a head of a dot printer that requires an ultra-hard tip.

More specifically, the purpose of the present invention is
It is to improve the wear resistance and rigidity of the supporting portion of the composite sintered material disclosed in 59-120218.

Means for Solving the Problems In order to achieve the above object, according to the present invention, a hard sintered portion containing 50% or more of either or both of diamond powder or high-pressure phase boron nitride powder, and the hard sintered portion. A composite sintered material comprising a support part made of a cemented carbide that is joined to the hard sintered part at one end, wherein the hard sintered part and the support part are joined by the hard sintering. Formed in the sintering process of the joint; and further, the diameter or equivalent diameter of the composite sintered material is 3 mm or less; the axial length of the hard sintered portion is 0.3 to 2 mm; The axial length of the supporting portion is 5 times the axial length of the hard sintered portion.
The supporting portion is made of a cemented carbide in which a carbide containing WC as a main component is bound by an iron-group metal, the average grain size of the carbide in the cemented carbide is 3 μm or less, and the amount of bound metal is A composite sintered material having a hard head is provided, which is characterized by being 7% by weight or more.

The average particle size of the diamond powder or the high-pressure phase boron nitride powder is preferably 30 μm or less, and a diamond or high-pressure phase boron nitride sintered body having a particle size within this range can provide a composite sintered material having excellent wear resistance and rigidity.

However, when making chips for cutting tools using diamond powder, if diamond powder with an average particle size of more than 10 μm is used as a raw material, the cutting edge of the cutting tool obtained by processing this composite sintered material will have a sharp edge. The hard sintered part is preferably made of diamond having a diameter of 10 μm or less or high-pressure phase boron nitride, because it cannot be formed into a compact shape and therefore does not have high performance.

When the hard sintered part is sintered with diamond powder as the main component, the diamond powder alone or 70
% Of diamond and the balance is sintered with a binder containing Fe, Co or Ni as a main component. A preferable example of such a hard sintered part is a sintered body of 70% or more diamond and WC-5 to 15% Co.

When powder of diamond alone is used as the material of the hard sintered portion, the infiltrant adjoining the binder component or diamond powder in the support material at the time of sintering of the hard sintered portion is hard burned. Sintering of the hard sintered part is achieved by infiltration into the binder material powder.

When the hard sintered part is mainly composed of high-pressure phase boron nitride powder, high-pressure phase boron nitride powder alone or 50% or more high-pressure phase boron nitride powder in 4a, 5a, 6a group carbides, nitrides, carbonitrides And sintered by adding aluminum and / or silicon as a binder. The powder of high-pressure phase boron nitride alone is infiltrated from the infiltrant placed adjacent to it to achieve sintering. Here, the high-pressure phase boron nitride is
It means cubic boron nitride and wurtzite boron nitride.

Next, the support part will be explained.Because the cemented carbide containing WC as the main component has not only high rigidity but also high wear resistance, and because it is a high-strength industrial material with high wear resistance. Also in the present invention, a cemented carbide containing WC as a main component is adopted for the supporting portion.

TiC and TaC contained in the cemented carbide for steel cutting are not effective in the case of the support portion of the present invention because they do not serve to improve the wear resistance and rather reduce the strength. However, a small amount of TaC or Cr ₃ C _{2 of} a few percent or less, which is effective in suppressing the grain growth of WC during sintering.
And VC are particularly effective for obtaining fine WC-based cemented carbide. Further, Co is most preferable as the binding metal, and Ni is
Are next preferred.

According to a preferred embodiment of the present invention, the grain size of the carbide in the cemented carbide forming the support is 2 μm or less, and the amount of binding metal is 12% by weight or more.

Further, according to one aspect of the present invention, the hard sintered portion and the support portion are joined together via an intermediate joining layer having a thickness of 0.5 mm or less.

As the intermediate bonding layer, a high-pressure phase boron nitride of less than 70% and the balance being one of Ti, Zr, and Hf carbides, nitrides, carbonitrides, or borides of Group 4a of the Periodic Table, or a mixture thereof or mutual mutual. It is preferable to use a solid solution compound as a main component and a material containing Al and / or Si in an amount of 0.1% by weight or more.

As described above, in the present invention, it is important that the joint between the hard sintered portion and the support portion is formed when the hard sintered portion is sintered. Therefore, at the time of hot pressing (sintering treatment) of the hard sintered portion, it is necessary to place the material powder of the hard sintered portion on the material of the supporting portion and perform hot pressing. At this time,
The material forming the supporting portion may be solid cemented carbide that has already been sintered, or may be powder of cemented carbide material.

Next, dimensional features of the composite sintered material cylindrical body of the present invention will be described.

The cross section of the composite sintered material of the present invention needs to have a diameter of 3 mm or less or an equivalent diameter. A composite sintered material with a diameter of more than 3 mm is not suitable as a material for drilling holes for printed circuit boards. Further, even if it is used after grinding, the grinding allowance is large and it is uneconomical. Here, the equivalent diameter means a value converted into the diameter of a circle having the same cross-sectional area.

Moreover, the axial length of the hard sintered portion is in the range of 0.3 to 2 mm. If it is less than 0.3 mm, the cutting edge cannot be formed when it is used as the tip of the drill, and if it exceeds 2 mm, it is uneconomical because it uses a large amount of expensive diamond powder etc. The risk increases.

Further, the length of the supporting portion of the composite sintered material of the present invention needs to be 5 times or more the length of the hard sintered portion. When making a drill, it is necessary to secure the cutting edge length of the drill and to bury the end in the shank. Therefore, as mentioned above, a supporting portion having a length 5 times or more the length of the hard sintered portion is required. Becomes A circular shape is generally desirable as the cross-sectional shape of the composite sintered material,
There are flat drills as well as drills, and the shape is not limited to a circular shape and may be a square shape. This is determined by manufacturing difficulty and the shape of the final product.

Function The present invention is as described above in Japanese Patent Application No. 59-120218 and Japanese Patent Application No.
This is an improvement of the supporting portion of the composite sintered material disclosed in No. 59-120219. That is, as described above, in the composite sintered material of the present invention, the axial length of the support portion is 5 times or more the length of the hard sintered portion. Therefore, when used as a drill, there is a risk of breakage or bending of the support portion, and it is necessary to consider wear due to high-speed rotation. It has succeeded in providing a long-life drill that is free from bending. Therefore, the improvement of the support portion according to the present invention and its operation will be described in detail below.

First, one feature of the composite sintered material of the present invention is that the joint between the hard sintered portion and the support portion is formed in the sintering process of the hard sintered portion. As a result, the diamond or the high-pressure phase type boron nitride is exposed to a stable high temperature and ultrahigh pressure during manufacturing of the support part. Sintering of WC-Co is usually performed under vacuum at a temperature of 1300 to 1500 ° C, while sintering of diamond or high pressure phase type boron nitride is at the same temperature, but under ultra high pressure of 40,000 to 50,000 atm. Made in. Therefore, WC-Co is affected by this ultra-high pressure regardless of whether a pre-sintered one is used or whether it is simultaneously sintered with the hard part.

In order to manufacture the composite sintered material of the present invention, it is easier to use a pre-sintered support part. Therefore, the present inventor found the following phenomenon when exposing various kinds of sintered WC-Co alloys to the above conditions.

Generally, the mechanical properties of WC-Co alloys are determined by Co% and WC grain size. By the way, when the grain size of the WC crystal is 3 μm or more, the WC crystal is destroyed by ultra-high pressure processing, and its mechanical properties are significantly changed, which makes it difficult to manufacture a supporting portion having constant mechanical properties. . Therefore, the average grain size of the WC crystals of the cemented carbide of the supporting portion is set to 3 μm or less.

However, under the sintering conditions of diamond or high-pressure phase boron nitride, the WC crystal has an extremely good wettability with the liquid phase Co, so that the liquid phase Co penetrates and is destroyed in the destroyed WC crystal.
It has been confirmed by experiments by the inventors of the present invention that the mechanical properties of WC are not necessarily deteriorated because Co is bound to Co.

For example, according to the conventional technical knowledge, in the case of a WC-Co alloy having an average grain size of 1 μm or less, it was considered that the presence of a small amount of large WC crystals would cause the large WC crystals to be the starting point of fracture and reduce the strength. However, according to the experiments performed by the present inventors, the strength after the treatment may be increased due to the ultrahigh pressure. The phenomenon of such strength increase depends on the content of the binding metal in the cemented carbide. According to experiments conducted by the present inventors, this increase in strength is caused by the fact that large WC crystals are destroyed by ultra-high pressure application during the sintering of diamond or high-pressure phase boron nitride, and a bond metal penetrates between the destroyed WC crystals. It is thought that this is to combine these.

On the other hand, if the ultra-high pressure is completely hydrostatically applied, there is no problem, but in reality, industrial production is devised so that the pressurization approaches hydrostatic pressure. Therefore, it can be considered that the cemented carbide under ultrahigh pressure is subjected to an unreasonable deformation. For example, considering a WC-Co alloy as an example, if the content of Co is large, the alloy can follow the deformation, but if it is small, defects such as fine cracks or holes can occur in the most deformed part. There is a nature.

After applying ultra high pressure and high temperature heating to alloys with various Co contents, the transverse rupture strength was measured. When the Co content was 7% or less by weight, the transverse rupture strength value was higher than that before the ultra high pressure high temperature treatment. To fall,
It has been found that if it exceeds 12%, it will rather improve.

When the content is 7% or less, it is considered that the WC crystal was destroyed by the ultrahigh pressure, and Co could not follow this, resulting in a defect. 12%
The reason why the transverse rupture strength is improved in the above cases is considered as follows.

The origin of fracture of WC-Co alloy is coarse WC crystal as described above,
It is said that there are vacancies and foreign phases. Since it is observed with a microscope before and after the treatment that there is no foreign phase, it is out of the question. The coarse WC crystal is as described above. Voids are pores of several μm to several hundreds μm, but it can be easily inferred from the example of HIP that they are crushed by external pressure or filled with Co. It is considered that this tendency is further promoted because the treatment temperature is the same in the case of HIP and the manufacturing process of the composite sintered material of the present invention, and the pressure is higher by one digit or more in the case of the present invention.

With a WC-Co alloy having a Co% higher than 12%, for example 20%, the increase in transverse rupture strength was as large as 30% or more. As a result of examining the cause of the high increase rate of the transverse rupture strength, the following was found.

That is, the Co phase of WC-Co usually has an FCC structure, and when the carbon content of the alloy is low, nearly 10% of W is solid-dissolved, but the composition is generally close to that of pure Co. Therefore, in general, a WC-Co cemented carbide having a high Co content is easily deformed, and therefore, when strained, it is plastically deformed, and a so-called strain-stress curve has a gently horizontal shape. If this curve does not have a lying shape and rises linearly, the strength will increase. From this point of view, when the Co phase after the treatment under the conditions of high temperature and ultra high pressure was examined, it was found that W was in solid solution at about 15%, and it was found that the Co phase was not easily deformed. It was. The reason for this is considered as follows.

That is, the Co phase that precipitates from the Co-W-C ternary eutectic at that eutectic temperature contains about 20% W. During normal cooling after sintering, W precipitates from the ternary eutectic on the WC phase. However, in the manufacturing process of the composite sintered material of the present invention, after the sintering of the hard portion is completed, the heating power source is first turned off to cool and then the pressure is released. Ie W
When it is attempting to precipitate from the Co phase, it is still under ultra-high pressure, and under such ultra-high pressure, the diffusion rate in the solid is remarkably reduced, and the precipitation on the WC phase is prevented. This can be understood from the fact that the Co phase in the WC-Co cemented carbide of the support portion of the composite sintered material of the present invention is a solid solution of a large amount of W. Therefore, in the present invention, the WC cemented carbide containing a high content of the binding metal in a range that cannot be normally used due to its deformation is used as the supporting portion.

That is, according to the present invention, the average particle size of the carbide in the cemented carbide forming the support portion is 3 μm or less, and the amount of the binding metal is 7% by weight or more.

Further, according to a preferred embodiment of the present invention, the grain size of the carbide in the cemented carbide forming the support portion is 2 μm or less, and the amount of binding metal is 12% by weight or more.

Hereinafter, the present invention will be described with reference to examples.

Example FIGS. 3 (a) and 3 (b) of the accompanying drawings respectively show the appearance of the composite sintered material of the present invention.

The composite sintered material cylindrical body 23 shown in FIG. 3 (a) is a hard sintered portion.
The hard sintered portion 21 and the support portion 22 are integrally joined in the sintering process of the hard sintered portion 21.

On the other hand, in the composite sintered material cylindrical body 23 shown in FIG. 3 (b),
The hard sintered part 21 and the support part 22 have an intermediate bonding layer between them.
It is joined with 24 interposed.

Next, a method for manufacturing the composite sintered material cylindrical body of the present invention will be described.

As described in detail in Japanese Patent Application No. 59-120219 filed by the present applicant, the present inventors first hot-press a composite material block having a large cross-sectional area to manufacture a composite sintered body block, and discharge this. By cutting into a rod-shaped body having a small cross section by wire cutting, it has succeeded in providing a composite sintered material having a small diameter, an elongated shape, and a hard head.

That is, in the method described in Japanese Patent Application No. 59-120219,
Bonding a first material layer for a hard sintered body containing 50% or more of diamond powder or high-pressure phase boron nitride powder, and a hard sintered body of the first material in a sintering process of the first material layer And the second material layer to be stacked are placed in the same hot press container in the pressing direction, and hot pressed under high temperature and high pressure to sinter the first material layer and at the same time to obtain the obtained hard-baked material. The composite is bonded to the second material layer side to form a composite material block having a layer of a hard sintered body having a predetermined thickness, and the composite material block is cut in the material layer thickness direction by a discharge wire cutting method. Then, two or more elongated composite rod-shaped bodies each having a hard sintered body on its head are cut out.

When this composite material is hot pressed and sintered, according to the present invention, the axial length of the composite material block should be 3 times, preferably 2 times or less than its equivalent diameter. When hot pressing a composite material block with an axial length exceeding 3 times, the pressure distribution in the composite material block becomes irregular,
This is because bending or the like occurs.

A method of cutting out the composite material cylindrical body shown in FIG. 3 will be described. The composite sintered body block 33 obtained by hot pressing as described above has a diamond sintered body layer 31 having a thickness of 1 mm and a cemented carbide layer 32 bonded thereto as shown in FIG. 4 (a). When the intermediate bonding layer is included, the diamond sintered body layer 31 and the cemented carbide layer 32 are bonded via the intermediate bonding layer 34 as shown in FIG. 4 (b). In the illustrated example, a cylindrical composite sintered body block is shown, but it goes without saying that the composite sintered body block may be a cylindrical body or a prismatic body.

As shown in FIG. 5, these composite sintered body blocks were cut into rod-shaped bodies having a cross-section with an equivalent diameter of 3 mm or less in the direction coaxial with the composite sintered body blocks by a discharge wire cutting method to form a third rod.
A composite rod having a hard head as shown in FIGS. (A) and (b) is cut.

In this discharge wire cutting method, a high voltage is applied between the wire and the composite sintered body block, and the wire is run in a tensioned state to cut the block, and the details of the method are described in, for example, U.S. Patent No. 4,103,137. See issue.

Hereinafter, specific production examples of the composite sintered material having a hard sintered body on the head of the present invention will be described.

Production Example 1 WC-12% Co cemented carbide ring with outer diameter 18mm, inner diameter 14mm, height 15mm, WC-12% Co cemented carbide column block with outer diameter 14mm, height 12mm, outer diameter 14mm, thickness Prepared a mixed powder consisting of a 0.5 mm thick WC-12% Co cemented carbide disc, 85% diamond powder with a particle size of 0.5 μm, and the balance WC-15% Co cemented carbide powder with a particle size of 0.5 μm or less. .

Insert the cemented carbide column block into the inner diameter of the cemented carbide ring, and fill the recess of 14 mm in diameter and 3 mm in depth formed by the inner surface of the cemented carbide ring and the upper surface of the cemented carbide column block with the mixed diamond powder. Post-pressurize the height of the mixed powder to 1.
After making it 5 mm and covering it with a cemented carbide disc, it was placed in an ultra-high pressure sintering apparatus and sintered under conditions of a pressure of 55 kb and a temperature of 1370 ° C. for 15 minutes. After cooling, decompressing and removing the upper cemented carbide disk of the enclosed container removed by grinding, a sintered diamond layer with a thickness of 1 mm was formed on the upper surface of the cemented carbide support with a height of 12 mm and formed around it. A composite block was obtained in which the cemented carbide ring was also bonded to the support and the sintered diamond layer.

As shown in FIG. 5, this composite block is mounted on an electric discharge wire cutting machine, and electric discharge wire cutting is performed.
A round bar with a diameter of 1 mm and a length of 13 mm from the axial direction of the composite block, the support part is made of WC-12% Co cemented carbide with an average grain size of 2 μm, and a 1 mm long sintered diamond layer is firmly formed on one end I got a cylinder.

Production Example 2 18 mm outer diameter and 18 mm inner diameter made of WC-12% Co cemented carbide
14mm, height 20mm ring, outer diameter 14mm, height 18mm WC-
_{1% Cr 3 C 2 -20%} Co cylinder block, an outer diameter of 14 mm, 1mm thick
Disk and 90% diamond powder with a particle size of 3 μm and the rest
Mixed powder consisting of Co powder, high-pressure phase boron nitride having a particle size of 3 μm (hereinafter cubic boron nitride is abbreviated as CBN) powder 60%
Then, a mixed powder having a composition of which the balance is (TiN-10% by weight A1) was prepared.

The CBN mixed powder dissolved in a solvent is applied to the upper surface of a cemented carbide column block to a thickness of 50 μm, and then the solvent is removed by heating, and the cemented carbide column block that has undergone this treatment is processed into a cemented carbide ring inner diameter. Inserted in.

Next, after filling the diamond mixed powder in the recess formed by the inner surface of the cemented carbide ring and the upper surface of the cemented carbide columnar block coated with CBN mixed powder, pressure molding to a thickness of 1 m
After forming a diamond mixed powder layer of m, the lid was covered with a cemented carbide disc.

Next, this container was placed in an ultra-high pressure sintering machine, and the pressure was 55 kb,
After sintering at a temperature of 1400 ° C. for 10 minutes, the container was taken out by cooling and reducing the pressure. When the upper cemented carbide disk of the container is ground away, a 0.5 mm thick sintered diamond layer is bonded to the upper surface of a 18 mm high cemented carbide support through a 25 μm thick sintered CBN layer, A composite block was obtained in which the cemented carbide ring was bonded to the support and the sintered diamond layer.

This composite block is mounted on a discharge wire cutting and processing machine, and by discharge wire cutting, a round bar with a diameter of 0.3 mm and a length of 18.5 mm is used from the axial direction of the composite, and the average particle size of the support is 0.7 μ
fine WC-1% of m Cr ₃ C ₂ consists -20% Co cemented carbide,
A 0.5 mm long sintered diamond layer is 25μ thick at one end.
As a result, a cylindrical body was obtained which was joined and formed through the sintered CBN interface layer of m.

Production Example 3 WC-0.5% VC-13% Co cemented carbide with a diameter of 20m on the upper surface
m, cylindrical block with an outer diameter of 24 mm and height of 25 mm with a circular recess of 3 mm, outer diameter of 20 mm, thickness of 0.5 mm WC-12% Co cemented carbide disc and diamond powder with a particle size of 0.5 μm A diamond mixed powder consisting of WC-15% Co cemented carbide powder with a particle size of 80% and the remainder of 0.5 μm or less was prepared.

This diamond mixed powder was filled in the recess in the upper surface of the cemented carbide column block and then pressed to form a diamond mixed powder layer having a height of 2.3 mm. Next, after covering with a cemented carbide disc on this, place it in the ultra-high pressure sintering equipment, pressure 55 kb, temperature
Sintered at 1400 ° C for 15 minutes.

After sintering, take out the enclosed container and grind off the cemented carbide lid on the top surface to have a sintered diamond layer with a thickness of 1.5 mm in the circular recess on the top surface, which is a composite block firmly bonded to the surrounding alloy container. was gotten.

This composite block was mounted on an electric discharge wire cutting machine, and by discharge wire cutting, a round bar with a diameter of 2 mm and a length of 23.5 mm was used from the axial direction of the composite block, and the support part had an average grain size of 0.7 μm WC-0.5% VC- A cylindrical body made of 13% Co cemented carbide and having a 1.5 mm long sintered diamond layer fixedly formed on one end thereof was obtained.

Production Example 4 WC-12% Co cemented carbide ring with an outer diameter of 18 mm, an inner diameter of 14 mm, and a height of 15 mm, an outer diameter of 14 mm, a cylindrical block of WC-2% TaC-16% Co alloy with a height of 12 mm, and an outer diameter of 14 mm , 0.5 mm thick WC-12
% Co Cemented Carbide Disc, CBN85% with 3μm grain size and the balance TiN
After mixing _0.82 powder and Al powder in a weight ratio of 80:20,
After heat treatment at 000 ° C. for 30 minutes in a vacuum furnace, a CBN mixed powder consisting of powder pulverized to 0.3 μm was prepared.

Diameter formed by the inner surface of the cemented carbide ring and the upper surface of the cylinder block by inserting the cylinder block into the inner diameter of the cemented carbide ring
The CBN mixed powder was filled in a recess having a depth of 14 mm and a depth of 3 mm and pressed to form a CBN mixed powder layer having a height of 1.7 mm. Then, cover with a cemented carbide disc and cover, place the entire cemented carbide container in the ultra-high pressure sintering device, then pressure 50 kb, temperature 1250 ℃
And sintered for 20 minutes.

After sintering, take out the cemented carbide container and grind off the WC-12% Co cemented carbide lid on the top surface to form a 1 mm thick sintered CBN layer on the top surface of the support part with a height of 12 mm. A composite block with a cemented carbide ring bonded to the support and the sintered CBN layer was obtained.

This composite block was mounted on an electric discharge wire cutting machine, and by electric discharge wire cutting, a square bar with a side of 1 mm and a length of 13 mm from the axial direction of the composite block was used to support WC-2% TaC-16 with an average grain size of 1 μm. % Sl alloy was obtained, and a long rectangular rod with a 1 mm long sintered CBN adhered to one end was obtained.

Production Example 5 WC-12% Co cemented carbide ring with outer diameter 40mm, inner diameter 36mm, height 40mm, WC-12% Co cemented carbide column block with outer diameter 36mm, height 34mm, outer diameter 36mm, thickness 0.5 A WC-12% Co cemented carbide disc having a diameter of 3 mm, a CBN powder having a composition of 60% by volume of a CBN powder having a particle diameter of 3 μm and a balance (TiN-10 wt% Al) was prepared.

First, the CBN mixed powder is pressure-molded into a disc having a diameter of 36 mm and a thickness of 2.5 mm, and the cemented carbide ring, the CBN molded body, the cemented carbide column block, and the CBN molded body are inserted into the inner diameter of the cemented carbide ring from the bottom. Then, the cemented carbide discs were laminated in this order, and the entire set container was placed in an ultrahigh pressure sintering apparatus and sintered at a pressure of 40 kb and a temperature of 1200 ° C. for 20 minutes.

After taking out after sintering and grinding and removing the upper and lower cemented carbide lids, a sintered CBN layer with a diameter of 36 mm and a thickness of 1.5 mm is fixedly formed on the upper and lower surfaces of the cemented carbide column block with a height of 34 mm. A composite block covered with an alloy ring was obtained.

Next, this composite block was mounted on an electric discharge wire cutting machine, and by a discharge wire cutting, from the axial direction of the composite block, a 2.5 mm diameter and 37 mm long round bar was used to form a sintered CBN layer of 1.5 mm length at both ends. Was adhered and formed.

This round bar is further cut at the center in the length direction and cut into two parts. The round bar has a diameter of 2.5 mm and a length of 18 mm. The supporting part is made of WC-12% Co cemented carbide and has a length of 1.5 mm at one end A rod-shaped body on which the CBN layer was firmly formed was obtained.

In the present specification,% is shown as volume percent unless otherwise specified.

Application Example An example in which the composite sintered material of the present invention is applied to a drill is shown in FIG.

As shown in FIG. 6 (a), a hole 26 having a circular cross section and a diameter substantially the same as that of the composite sintered material is formed at the tip of the shank 25 of the drill. One end of the supporting portion of the composite sintered material 23 of the present invention is pushed into this hole 26 and fixed. At this time, a brazing material may be dropped into the hole 26 and then brazing.

As shown in FIG. 6 (a), the composite sintered material 23 fixed to the shank was bladed to obtain a drill as shown in FIG. 6 (b). The drill manufactured by using the composite sintered material of the present invention does not include a complicated joint portion by electron beam welding, and has a strong and robust structure as a whole. Therefore, it is possible to perform highly efficient drilling even for a high-performance printed circuit board such as a glass epoxy substrate.

Furthermore, since the cross section of the composite sintered material of the present invention is cut into an arbitrary shape, when the cross section is circular, when it is pushed into the hole drilled at the tip of the shank of the drill as shown in FIG. 6 (a). Also, it can be installed without requiring special processing, and the cutting allowance for cutting the cutting edge is small, making it economical.

EFFECTS OF THE INVENTION As described above, the present invention improves the strength and flexural strength by improving the composition of the supporting portion in the composite sintered materials described in Japanese Patent Application No. 59-120218 and Japanese Patent Application No. 59-120219. It succeeded in providing a strong support. That is, the applicant has disclosed in Japanese Patent Application No. 59-120218 a composite sintered material for a drill having a long life, which realizes easy and high-performance drilling of a difficult-to-cut substrate such as a glass epoxy substrate. Further, by improving the support portion, wear resistance and rigidity are improved, and a long-life drill or the like can be easily manufactured even under severe use conditions such as high-speed rotation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the structure of a prior art composite diamond sintered body. FIG. 2 shows a drill in which a composite sintered body of the prior art is fixed to the cutting edge. 3 (a) and 3 (b) respectively show a composite sintered material cylinder according to an embodiment of the present invention. 4 (a) and 4 (b) are perspective views of the composite sintered material block before cutting out the composite sintered material columnar body of the present invention. FIG. 5 shows a position where a cylindrical body having a small cross section is cut out from the composite material block. FIG. 6 (a) shows the composite sintered material cylindrical body of the present invention fixed to the shank of the drill, and FIG. 6 (b) shows the drill thus obtained. (Main reference number) 11 …… Sintered diamond layer of conventional diamond tool,
12 …… Cemented Carbide Support, 13 …… Conventional Composite Sintered Diamond Tip, 15 …… Shank, 21 …… Hard Sintered Part of Composite Sintered Material of the Present Invention, 22 …… Support, 23 …… Composite sintered material of the present invention, 24 …… Intermediate joint, 31 …… Hard sintered portion of composite material block, 32 …… Support portion, 33 …… Composite material block, 34 …… Intermediate joint,

Claims (3)

[Claims] 1. A hard sintered part (21) containing 50% or more of either or both of diamond powder and high-pressure phase boron nitride powder, and a support part (1) joined to one end of the hard sintered part (21). 22) and a tool made of a composite sintered material (23) composed of and a wear-resistant component having a hard head, the hard sintered part (21) and the support part (22) are joined together by hard sintering. It was formed during the sintering process of the part (21), the composite sintered material (23) has a diameter or equivalent diameter of 3 mm or less, and the hard sintered part (21) has an axial length of 0.3 to 2 mm. The axial length of the supporting portion (22) is 5 times or more the axial length of the hard sintered portion (21), and the supporting portion (22) is made of a carbide containing WC as an iron group metal. Made of cemented carbide, the average grain size of carbides in this cemented carbide is 3 μm or less, and the bonding metal is Co. Not less than%, diamond powder or average particle size of the high-pressure phase boron nitride powder is 10μm or less, abrasion resistant component with a tool or a hard head, characterized in that the hard sintered section (21). 2. A tool according to claim 1, wherein the grain size of carbides in the cemented carbide is 2 μm or less, and the amount of binding metal is 12% by weight or more, or wear resistance having a hard head. Sex parts. 3. The method according to claim 1 or 2, wherein the hard sintered part (21) and the supporting part (22) are bonded to each other through an intermediate bonding layer having a thickness of 0.5 mm or less. Abrasion resistant component having the described tool or hard head.