JPS58213676A - Diamond sintered body for tool and manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Currently, a sintered body in which diamond □ content is 70% by volume or more and diamond particles are bonded to each other is sold, and is used for cutting non-ferrous metals, plastics, hexaramic, dressers, etc.
Used as drill bits and wire drawing dies. In particular, when these diamond sintered bodies are used as dies for cutting nonferrous metals or drawing wire rods such as copper wire, their performance is extremely excellent. However, at present, there is no diamond sintered body that has satisfactory performance for drawing drill bits and wires with high hardness, such as brass-plated high carbon steel wires. The present invention relates to a diamond sintered body that can also be used to draw drill bits and highly hard wire rods.

First, in order to investigate the reasons why commercially available diamond sintered bodies do not show satisfactory performance when used as drill bits, we investigated the following: particle size of 1 μm or less, particle size of 80 to 60 μm, particle size of 80 to 1
Andesite was cut using three types of 00 μm diamond sintered bodies. As a result, diamond sintered bodies with a particle size of 1 μm or less do not break at the cutting edge.

However, there was a lot of wear. On the other hand, a sintered body with a particle size of diamond particles of 80 to 60 μm and a diamond particle size of 80 to ioo μm
The cutting edge of both sintered bodies was damaged in the initial stage. The reason for this can be inferred as follows. As shown in FIG. 1, the strength of the diamond sintered body decreases as the grain size increases. Fine-grained diamond sintered bodies have high transverse rupture strength and excellent toughness, so the cutting edge is difficult to break, but since each particle is held by a small diamond skeleton, the bonding force between the individual particles is weak. Therefore, individual particles tend to fall off during cutting, which is thought to result in poor wear resistance. On the other hand, coarse-grained diamond sintered bodies are held by a large skeleton, and the bonding force between individual diamond particles is strong, so although they have excellent wear resistance,
Since the skeleton part is large, once a crack occurs, it is likely to propagate easily and cause the cutting edge to break. A diamond sintered body that can be used for these purposes must have excellent wear resistance and high toughness.

The present inventors continued intensive research in order to develop a diamond sintered body with excellent wear resistance and toughness.

As a result, diamond particles with a particle size of lO~100 μm are combined with ultrafine diamond particles of 1 μm or less and WC of 1 μm or less or with the same crystal structure (Mo, W).
A sintered body using a binder containing C and iron group metals, or a trace amount of boron or boride, has the good wear resistance of a coarse-grained diamond sintered body and the high toughness of an ultra-fine-grained diamond sintered body. It turned out that it has the following characteristics.

In order to find the optimal composition of the above-mentioned materials, the present inventors
Diamond sintered bodies with different coarse diamond particle sizes and content, and the content of diamond particles of 1 μm or less contained in the binder were produced as prototypes, and evaluated by cutting andesite. The results are shown in FIGS. 2 and 3. In the figure, 1 indicates normal wear, and 2 indicates the area where the cutting edge is damaged. If the coarse diamond grain size is 10 μm or less, the wear resistance will decrease. If the coarse diamond particle size exceeds 100 μm, cracks will occur within the diamond particles during sintering, and it is thought that the cutting edge will break through these cracks and the amount of wear will increase. The content of coarse diamond particles is 50 to 8 by volume.
5% is good. If the content of coarse diamond particles is less than 50%, the amount of binder containing fine diamond particles increases, resulting in a decrease in wear resistance. On the other hand, if the content of coarse diamond exceeds 85%, the toughness decreases because the coarse diamonds bond together.

The particle size of the fine diamond particles in the binder is preferably 1 μm or less. The particle size of fine diamond particles is 111Tn.
The thickness is preferably 0.5 μm or less. When the particle size of fine diamond particles exceeds 1 μm, toughness decreases.

The content of fine diamond particles in the binder is 60% by volume.
~9096 is preferred. If the content of fine diamond particles is less than 60%, the wear resistance of the binder phase decreases, the binder phase wears out early, and coarse diamond particles fall off. On the other hand, the content of fine diamond particles is 9096
If the value exceeds 1μ, the binder becomes brittle, or the content of wc- or (Mo, W)C, which has the same crystal structure as this, decreases. Diamond grains of n or less grow and the toughness decreases.

In particular, in the sintered body of the present invention, the weight of the sintered body is 0.00'5 to 0.
．． When containing 15% boron or boride, the performance is further improved. Usually, diamond particles are sintered under ultra-high pressure and high temperature by the phenomenon of diamond dissolution and precipitation using a catalyst such as an iron group metal. When boron or boron compounds are added, borides of iron group metals are produced, which lowers the melting point and increases the melt deposition rate. □As a result, bonding parts between diamond particles (diamond skeleton parts) grow, and the retention of diamond particles. It can be assumed that the power has improved. If the content of boron or boride is less than 0.00596, the formation of the diamond skeleton portion is slow. On the other hand, if the boron or boride content exceeds 0.15%, a large amount of boron will enter the diamond skeleton, reducing the strength of the diamond skeleton.

Furthermore, the sintered body of the present invention can be used not only for rock cutting or excavation purposes, but also for drawing highly hard wire rods.

For example, when a brass-plated steel wire is drawn using a commercially available diamond sintered body, the diamond grain size is 80~
In the case of a 60μm sintered body, the diamond skeleton part breaks off and damages the inner surface of the die, which has a major impact on the lifespan. On the other hand, in the case of a sintered body having a diamond grain size of 2 to 6 μm, the diamond grains fall off and damage the inner surface of the die, leading to the end of its life. Furthermore, in a diamond sintered body with a diameter of 1 μm or less, several diamond particles fall off as a group, causing scratches on the inner surface of the die.

When a wire with high hardness (for example, a brass-plated steel wire) is drawn using the sintered body of the present invention, there are few scratches on the surface of the wire and the wire has a long life.

The reason why the sintered body of the present invention has excellent performance is presumed as follows. In other words, since the binder of the sintered body used in the present invention is made up of fine particles of 11 m or less in size, it does not form skeletons between large diamond particles, and the inner surface of the die is pulled due to chipping or falling off of the diamond skeletons, resulting in deep large diamond particles. Does not cause any damage. In addition, diamond particles are bonded with diamond particles of 1 μm or less contained in the binder, and WC, which has the same crystal structure as this (Mo , W) C, and iron group metals (Fe aNi*Co
) and diamond have a good affinity, so it is thought that diamond particles do not fall off. Furthermore, the binder contains diamond particles with a fine particle size of 1 μm or less, and the binder has excellent wear resistance, so that the binder does not wear abnormally during wire drawing. When the sintered body of the present invention is processed into a die, the wear resistance of the bonded part is excellent, but it is inferior to coarse diamond particles of 10μ or more, so the bonded part is slightly more durable than coarse diamond particles.
It becomes depressed. When wire is drawn in this state, the load applied to the diamond part increases, but the load applied to the binder decreases, so the fine diamond particles in the joint part fall off in clusters. Without a doubt,
It is unlikely to damage the inner surface of the die.

The diamond raw material powder used for the sintered body of the present invention is 10
These are diamond particles with a diameter of 1 μm or more, and micron powder with a diameter of 1 μm or less, preferably 0.5 μm or less. Either synthetic diamond or natural diamond may be used.

This diamond powder and cage or (Mo, W)C
and Fe *Co sNi iron group metal powder or a powder obtained by adding boron or boride thereto are uniformly mixed using a means such as a ball mill. This iron group metal may be infiltrated during sintering without being mixed in advance. Or (Mo, W), as in the previous application of the present inventors (Japanese Patent Application No. 52-51881), there is a penalty for mixing pots and balls during ball milling.
A diamond powder is prepared using a sintered body of a carbide of C and an iron group metal, and at the same time as the diamond powder is ground in a ball mill, a fine powder of a sintered body of a sintered body of (Mo, W)C and an iron group metal is mixed in from a pot and ball. There is a way.

The mixed i-powder is placed in an ultra-high pressure device and sintered under conditions where the diamond is stable. At this time, it is necessary to sinter at a temperature higher than the temperature at which a eutectic liquid phase appears between the iron group metal and the compound such as carbide used.

Although the ratio of compounds such as carbides and iron group metals that serve as binding materials for diamond in the sintered body cannot be unambiguously determined, it is necessary that the amount is at least sufficient for the compound to exist as a solid during sintering. For example, when WC is used as a compound and Co is used as a binding metal, the quantitative ratio of WC and Co needs to include 50% or more by weight of the former.

When using the sintered body of the present invention as a drilling tool, in order to further improve the toughness of the diamond sintered body, the sintered body of the present invention may be bonded to a support such as cemented carbide during ultra-high pressure sintering. is also possible.

When the diamond sintered body of the present invention is used to draw a high-strength wire rod, high pressure is generated on the inner surface of the sintered diamond die, but when the diamond sintered body has a small outer diameter and a thin wall thickness, The diamond sintered body may crack in the vertical direction.

In such a case, it is possible to prevent vertical cracking during wire drawing by surrounding the outer periphery of the diamond sintered body with a support such as a cemented carbide and applying preload from the outer periphery of the diamond sintered body.

In addition to drilling tools and dies, the sintered body of the present invention can also be used as cutting tools and dressers.

This will be explained in detail below using examples.

Example 1 Synthetic diamond powder with a particle size of 0.5 μ and WC and Co
The powder was ground and mixed using a pot and ball made of WC-Co cemented carbide. The composition of the obtained mixed powder was 80% by volume of fine diamond with an average particle size of 0.3 μm, WCl2
% by volume, and Co8% by volume. This mixed powder and particle size 2
Diamond powder with a diameter of 0 to 80 μm in a volume ratio of 75:2
5. This finished powder was packed in a container made of Mo, and first a pressure of 55 Kb was applied using an ultra-high pressure device, and then heated to 1450° C. and held for 30 minutes.

When the sintered body was taken out and its structure was observed, it was found that diamond particles of 20 to 30 microns were bonded via a binder containing ultrafine diamond particles. Next, this sintered body was processed to create a cutting tool with a compressive strength of 1500KF/α.
2 andesite using a mold cutter at a speed of 207 minutes and a depth of cut of 1.
Cutting was carried out for 1 hour at a feed rate of 0.4 mm. For comparison, a commercially available diamond sintered tool bit for drilling tools was also prepared and tested at the same time. A photograph after the test is shown in Figure 4.

The sintered body of the present invention in alb) has no chipping at the cutting edge and is slightly worn, whereas the sintered body for commercially available excavation tools in c) and d) has a large chipping at the cutting edge.

Example 2 A binder powder shown in Table 1 was prepared. The fine diamond particles used were those with a diameter of 0.8 μm.

Table 2 shows this binder and diamond particles with a particle size of 5 μm or more.
A finished powder was prepared by mixing in the proportions shown below.

After sintering these finished powders in the same manner as in Example 1,
A cutting tool was prepared, and granite was cut using a shaper at a speed of 80 m/min, depth of cut of 1 m, and feed rate of 0.8 jIx for 120 minutes. The results are also shown in Table 2.

Example 3 Diamond particles with an average particle size of 0.5 μm and WCe Co
and boron powder were pulverized and mixed using a pot and pole made of WC-Co cemented carbide. The composition of the obtained mixed powder was 81% by volume of fine diamond with an average particle size of 0.8μ, WCI
The content was 0% by volume, 9% by volume of Co, and 1.0% by volume of boron. This mixed powder was mixed with 228 diamond particles having a particle size of 30 to 40 μm to prepare a finished powder. When the boron content was measured, it was 0.igs% by weight.

This finished powder was sintered in the same manner as in Example 1.

Using these sintered bodies, a core pit consisting of eight teeth with an outer diameter of 50 IIL1/L was created, and andesite was excavated at a speed of 20 m/min. For comparison, a core pit of the above-mentioned sintered body containing no boron and a commercially available diamond sintered body for use in drilling tools was also prepared and subjected to an excavation test.

As a result, the boron-containing sintered body of the present invention was still usable even after 20 m excavation. Furthermore, the sintered body containing no boron could be excavated for 20 m. On the other hand, the cutting edge of a commercially available core pit for drilling tools broke off after 6 m of excavation and became unusable.

Example 4 Diamond powder with an average particle size of 0.3 μm and WC powder were mixed in a volume of 9=1. This mixed powder and particle size 80-40
A finished powder was prepared by mixing diamond particles of μm 2 at a ratio of 1:3, and the powder was filled into a container made of cemented carbide. A Co plate was placed on top of the powder and sintered in an ultra-high pressure and high temperature device.

When the sintered body was taken out and observed, it was found that c.
o penetrated uniformly and sintered the diamond particles. Using this sintered body, a die with an inner diameter of 0.25 M was created, and a brass-plated steel wire was drawn at a wire speed of 800 m/min. For comparison, a commercially available diamond sintered die consisting of diamond particles of 80 to 40 microns was also prepared and tested. As a result, the sintered body of the present invention was able to draw 5.3 tons of wire, whereas the commercially available sintered diamond die was able to draw 2 tons of wire.
Example 5 Diamond particles having a particle size of 4θ to 60 μm and the binder powder prepared in Example 8 were mixed in a ratio of 4=1. This powder was filled into a container made of Mo, and then sintered in the same manner as in Example 8. This sintered body was taken out, a dresser was made, and a SiC-based grindstone was dressed 200 times.

For comparison, a commercially available sintered body dresser made of diamond particles with a particle size of 40 to 60 μm was also prepared and subjected to similar tests.

As a result, the flank wear rlj of the sintered body of the present invention is o, ai
mx, whereas the dresser of the commercially available diamond sintered body was 0.58M.

[Brief explanation of drawings]

Figure 1 shows the strength (transverse rupture strength) of a diamond sintered body.
This shows the relationship between diamond grain size and diamond particle size. Second
The figure shows the particle size of coarse diamond particles and rock cutting performance in the sintered body of the present invention. FIG. 3 is a graph showing the content of coarse diamond and rock cutting performance in the sintered body of the present invention. Figure 4 (8) and 8) are scanning electron micrographs of the cutting edge of the sintered body of the present invention after rock cutting, magnified 30 times and 500 times, and Figures 5 (--(B) These are scanning electron micrographs of the cutting edge of a diamond sintered body for tools after rock cutting, magnified 80 times and 500 times. Figure 2 on the left - 419 - Figure 3 Coarse-grained diamond content (volume %)
. Figure 5 (A) x Oυ Procedural Amendment Written on March 8, 1980 Kazuo Wakasugi, Commissioner of the Patent Office 1. Indication of the case 1987 Patent Application No. 95104 2. Name of the invention Diamond sintered body for tools and its manufacturing method 3, and its relationship to the case of the person making the amendment Patent applicant address 5-15 Kitahama, Higashi-ku, Osaka Name (21
3) President of Sumitomo Electric Industries, Ltd. Tetsube Yojo 4.1 Agent address: Within Sumitomo Electric Industries, Ltd., 1-1-3 Shimaya, Konohana-ku, Osaka (telephone: Osaka 461-1031) 6. In the specification subject to amendment Detailed Description of the Invention Column 7, Contents of Amendment (1) On page 15, line 9 of the specification, "Speed 207 minutes" is corrected to "Speed 20 m/min." (2) Same book, same page, lines 12-13, ra, b) J is corrected to ``Figure 4 (A), (B) J. (3) Same book, same page, line 13, rc), d) J is changed to ``Figure 4 (A), (B) J. Figure 5 (C)) and (B) are corrected to J. (4) Table 2 on page 17 of the circular is corrected to the next page.

Claims (1)

[Claims] (1) Coarse diamond particles with a particle size of 10 μm or more and 100 μm or less occupy 50 to 8596 by volume, and the remainder is 1 μm.
The following ultra-fine diamond particles with a capacity of 60 to 90
% and 1 μm or less of WC or a binder composed of (Mo, W) C having the same crystal structure as this and an iron group metal. (2) Coarse diamond particles with a particle size of 10 μm or more and 100 μm or less account for 50 to 8096 by volume, and the remainder is 60 to 90% by volume of ultrafine diamond particles of 1 μm or less, which is 1 μm.
WC of less than m or having the same crystal structure (Mo
, W) 0.005 to 0.00% by weight of C and iron group metals.
A diamond sintered body for tools, characterized in that it contains 1596' boron or/and boride. (3) WC used as a part of the binder in the sintered body according to claim (1) or (2), or the ratio of (Mo, W) C and iron group metal having the same crystal structure. A diamond sintered body for tools, characterized by having a higher carbide content than that corresponding to the eutectic composition of the diamond. (Diamond powder of 400 to 100 μm, ultrafine diamond powder of 1 μm or less, diamond powder of 1 μm or less, or a mixed powder of (Mo, W) having the same crystal structure as this (Mo, W) and iron group metal powder was prepared and processed in an ultra-high pressure and high temperature apparatus. It is characterized by hot pressing under high temperature and high pressure where the diamond is stable.Coarse diamonds of 10-100μm account for 50-8596 in volume, and the remainder is fine-grained diamonds of 1μm or less in volume of 60-9096. and has a crystal structure of 1 μm or less or the same crystal structure as this (Mo, W)
A method for manufacturing a diamond sintered body for tools made of a binder made of C and an iron group metal. (5) Create diamond powder of 10 to 100 μm, ultrafine diamond powder of 1 μm or less, WC of 1 μm or less, or a mixed powder of C + boron or boride and iron group metal having the same crystal structure (Mo mW), Coarse diamond particles of 10 to 100 μm account for 50 to 85% of the volume, and the remainder is ultrafine diamond of 1 μm or less, which is characterized by hot pressing under high temperature and high pressure using an ultra-high pressure and high temperature equipment to stabilize the diamond. Particles by volume 6
0 to gθ% and 1 μm or less WC or a binder composed of (Mo + W)C having the same crystal structure, an iron group metal, and boron or/and boride, containing boron or/and boride. The amount is 0.0 of the sintered body by weight.
05 to 0.15% of a diamond sintered body for tools. (6) 10-100μm diamond powder, 1μm
A mixed powder of the following ultrafine diamond powder, WC of 1 μm or less, or (Mo, W)C having the same crystal structure is created, and a type of iron group metal is placed on top of this mixed powder.
Or, after placing two or more alloy plates, use an ultra-high pressure and high temperature device using a solid pressure medium to produce a liquid phase of one or more alloys of iron group metals under high temperature and high pressure where diamond is stable. 10 to 100μ characterized in that the diamond particles are sintered by infiltrating the powder into the mixed powder.
50 to 85% by volume of coarse diamond particles of 1 μm or less, the remainder being 60 to 90% by volume of ultrafine diamond particles of 1 μm or less and WC of 1 μm or less or (Mo)W having the same crystal structure. ) A method for producing a diamond sintered body for tools, which is made of a binder made of c and an iron group metal. (7) Create a diamond powder of 10 to 100 μm, ultrafine diamond powder of 1 μm or less, WC of 1 μm or less, or a mixed powder of (Mo, W)C and boron or boride having the same crystal structure, and mix this. After placing an alloy plate of one or more iron group metals on the powder,
Using an ultra-high pressure and high temperature device using a solid pressure medium, diamond particles are produced by infiltrating a liquid phase of an alloy of one or more iron group metals into a mixed powder under high temperature and pressure conditions at which diamond is stable. Coarse diamond particles of io ~ 100 μm, characterized by sintering, have a capacity of 50
~85%, and the remainder is 60~90% by volume of ultrafine diamond particles of 1 μm or less and WC of 1 μη or less or (Mo, W)C having the same crystal structure as this, iron group metals, and boron or/ A method for producing a diamond sintered body for tools, the sintered body comprising a binder made of a boron and a boron, the content of boron and/or boride being 0.005 to 0.1596 by weight. (8) Claims Nos. (4), (5), (6), (7)
WC used as a part of the binder-forming powder in the manufacturing method described in section ) or having the same crystal structure as this (Mo
, W) Using a mixed powder in which the ratio of C and iron group metal is higher than that corresponding to the eutectic composition, ultrafine diamond grains are produced at a temperature higher than the eutectic formation temperature of carbide and iron group metal. A method for producing a diamond sintered body for tools, characterized by sintering while suppressing growth.