JPS59152065A - Diamond wheel for working hard fragile material - Google Patents

Abstract

PURPOSE:To obtain the captioned wheel which develops the superior performance in working fireresistive bricks, etc. and with which the amount of abrasion can be reduced and the service life can be prolonged by pulverizing a diamond sintered body synthesized at high temperature and high pressure and using said substance as grinding grains. CONSTITUTION:Since the tungsten-carbide layer in the conventional method can be removed in sintering a diamond sitered body at high temperature and high pressure, the problems that the strength of tungsten carbide is remarkably reduced at an excessively high temperature and the life of a high-pressure container is shortened at high pressure are eliminated. Therefore, temperature and pressure can be varied freely, and the part made of tungsten carbide can be replaced with diamond powder in a same apparatus, and the larger diamond sintered body can be synthesized. The granular diamond which is sharp and has a high strength can be obtained, and the amount of abrasion can be reduced, and the life can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diamond wheel for machining hard and brittle materials.

Recently, firebricks containing coarse-grained silicon carbide have been increasingly used to improve heat resistance.

Traditionally, when machining such bricks, the roughness is 30 to 60.
A diamond whetstone containing artificial diamond abrasive grains (
A diamond wheel (hereinafter simply referred to as a wheel) was used, which had a chip (hereinafter referred to as a chip) brazed to an alloy. However, since refractory crackers contain coarse grains of silicon carbide, the tips are subject to severe wear and are currently unable to demonstrate their full potential.

As a result of various studies and repeated experiments, the present inventors have found that performance can be significantly improved by increasing the size of diamond particles used in the chip. Judging from the experimental results, it was found that the appropriate size of the diamond particles is 2 mm to 2.5 mm.

However, synthetic diamonds of this size are difficult to obtain, and natural diamonds are too expensive. Moreover,
If natural diamond were to be used, apart from the cost, there would be a definite drawback that since it is a single crystal, it would have a well-developed crack surface, which would cause the tip to wear easily and the wheel life would not be extended as expected. I found out that there is.

On the other hand, artificial diamond fine powder is mixed with catalytic metals such as cobalt, iron, and nickel, and this is mixed under high temperature and high pressure (14
By sintering at a temperature of 00° C. or higher and 50 kbar or higher, a dense polycrystalline diamond sintered body can be easily obtained.

This sintered body was developed for the purpose of being used as cutting tools and diamond die tools, and for this reason, the shape of the sintered body is limited to disk-like or cylindrical shapes, and it is generally co-sintered with tungsten carbide. . Therefore, although this diamond sintered body has excellent performance as a tool due to the purpose-oriented development described above, it is difficult to apply it to a wide range of fields due to its limited shape and structure. be.

As part of expanding the uses of this diamond sintered body, the present inventors attempted to apply it to the chips of wheels for machining the aforementioned refractory bricks and the like. Then, I came up with the idea of crushing it and using it.

This invention was made based on the above-mentioned findings. That is, the present invention provides a method for processing hard and brittle materials that exhibits excellent performance by pulverizing a synthesized diamond sintered body under high temperature and high pressure and using this as granular diamond lumps as abrasive grains. It provides wheels.

In this invention, the diamond ring used as the abrasive grain is a pulverized diamond sintered body, but when the diamond sintered body is sintered under high temperature and high pressure, the conventional tungsten carbide layer is not required. It is. This is what the present inventors have discovered, and this has the following advantages.

In other words, in the conventional sintering method, the tungsten carbide and diamond powder are integrated, so the temperature and
There was a limit to sintering by varying the pressure. The first reason is that if the temperature is raised too high, the cobalt in the tungsten carbide will be absorbed by the diamond powder, resulting in a significant decrease in the strength of the tungsten carbide.

The second reason is that increasing the temperature and suppressing the movement of cobalt requires a significant increase in pressure, which shortens the life of the high-pressure vessel.

In this respect, the diamond sintered body for the diamond mass serving as the abrasive grain in the present invention may be sintered with only diamond powder. Therefore, there is no need to take any of the above problems into account, and the temperature and pressure can be changed quite freely. Furthermore, since the tungsten carbide portion can be replaced with diamond powder in the same device, it is possible to synthesize larger diamond sintered bodies.

By pulverizing such a diamond sintered body, it becomes sharp and strong granular polycrystalline diamond.

Therefore, the granular polycrystalline diamond ring obtained in this manner is crushed and then cut into pieces of, for example, 2 mm to 2 mm.
As shown in FIGS. 1 to 4, abrasive chips 1 were made using 5 mfi abrasive grains, and a plurality of these chips 1 were lined up and brazed to a steel base metal 2 to create a wheel 3. Then, the refractory bricks W were sent to this wheel 3 from the direction of arrow A using a trolley 4, and cut in the direction of arrow B while rotating the wheel 3.

As a result, the expected and satisfactory results as shown in FIGS. 8 and 9 were obtained.

In addition to the above-mentioned diamond wheels, 50~
Wheels made of No. 6 artificial diamonds (diameter 20
0) was also tested for comparison.

The workpiece material is anthracite firebrick, and the mechanical conditions are: wheel peripheral speed v = 850 m / rrfvr, depth of cut f =
1 mm, feed of the work material f = 200 mm/-, and T-mount cutting using cooling water.

The horizontal axis represents the amount of workpiece material ground, and the diamond layer (
If the vertical axis is the amount of wear with respect to the length (3 mm), then as shown in Fig. 8, a wheel using abrasive grains made from crushed sintered bodies exhibits extremely little wear. Also, when looking at this in terms of load, as shown in Figure 9, the net leg force is also small during fluctuations.

Therefore, when a crushed sintered body is used, it can be said that the wheel has a long life and low horsepower (good sharpness).

This is because the following characteristics of the chip I were utilized. In other words, materials sintered under high temperature and high pressure are fine powders (
It is a diamond aggregate of 1 to 10μ), and although each fine powder particle has a crystallographic face, since it is a polycrystalline body, the sintered body does not have a crystallographic face.

These results confirmed that the wheel is extremely suitable for grinding coarse refractories, alumina, ceramics, etc., and the wheel life is more than three times longer than conventional products.

By the way, when making a chip, diamond ring bodies made by crushing sintered diamond must be bonded using a bonding material, and high-temperature treatment is essential at this time.

However, it was found that during this high-temperature treatment, the surface of the diamond ring was partially graphitized, reducing the holding power of the diamond ring. Since the diamond particles used in this invention are sintered bodies of ultrafine particles of 1 to 10 μm in size, the ultrafine diamond particles on the surface of the crushed diamond mass begin to graphitize at a temperature of 700 to 800°C.

Therefore, the crushed polycrystalline diamond ring was subjected to foot marking such as plating to prevent graphitization.The method for applying metal coating is vapor phase plating (P
VD, CVD, etc.), wet plating (electroless plating), etc. are possible, but electroless plating is preferable from the viewpoint of productivity. Nickel, cobalt, or their alloys are preferred as coating materials due to their heat resistance and ease of coating, and the coating thickness is 1μ to avoid coating defects.
The above is preferable.

As a result, the temperature of the diamond ring was increased from 900°C to 10°C.
Graphitization could be completely prevented even if the temperature was raised to 00°C for a short time. Furthermore, by preventing graphitization, which is the only drawback of ultrafine diamond, it became possible to use a hard metal binder sintered at high temperatures, successfully extending the life of the tool.

The effect of the coating is specified as follows.ru0 b) Prevention of graphitization.

口）Improved adhesive strength with binding materials.

c) Strengthening of retention as a result of b) and mouth).

Furthermore, in order to further improve such coating effects, after wet plating, vapor phase plating of borides, carbides, nitrides, etc. of group metals such as ■, ■, and ■ group metals is used as the second layer. Preferably, this is done by the techniques PVD or CVD.

Therefore, an example of a method of applying a metal coating to electroless plating of a diamond ring will be described.

Diamond ring (particle size 1~3rnml → sensitization treatment (
Nippon Kanigen Co., Ltd., Pink Schumer (product name: 10x liquid, room temperature 5 minutes) → Washing with water → Activation treatment (Japan Kanigen Co., Ltd., Red Schumer (product name) 5x liquid, 5 minutes at room temperature)
→ Wash with water → N1 plating (Nippon Kanizen Co., Ltd., 5B-55 (product name) 60″C, 20 minutes) → Wash with water → Dry.

As explained above, the chip in the wheel for machining hard and brittle materials according to the present invention uses as abrasive grains obtained by pulverizing a diamond sintered body synthesized under high temperature and high pressure to form granular diamond rings. Because of this, it exhibits excellent performance and is easy to manufacture.

Next, the content of the present invention will be specifically explained with reference to Examples.

<Example 1> Average particle size: 1μ artificial diamond fine powder and average particle size:
Using 0.1μ cobalt powder as a raw material powder, cobalt powder = 8% by volume (hereinafter, % is % by volume) using the usual method.
and artificial diamond fine powder and unavoidable impurities: A mixed powder consisting of the remainder is mixed to form a compact, and this is heated at a temperature of 1
50C1'C1 High pressure sintering was performed under the conditions of pressure = 60 kb, holding time: 30 minutes, diameter = 15 mm, thickness: 10 mm.
A diamond sintered body was obtained, and this was crushed by an attritor to obtain a diamond ring having an average particle size of 2 mm. Then, using this diamond ring as an abrasive grain and using copper, tin, and iron as a binder in the same way as a normal chip, the temperature was 11) 0°C, the pressure crab was 3oo'gt, and the holding time was 5 minutes. A chip having a length of 30 mm, a width of 5 mm, and a thickness of 3 mm was produced by pressure sintering. Next, Figures 1 and 2
As shown in the figure, the above-mentioned grinding chips 1 were brazed to a steel base metal 2 at equal intervals along the circumferential direction to create a wheel 3 as described below, and the wheel 3 was subjected to a test.

Wheel shape: cup-shaped grinding wheel Number of chips installed: 12 pieces Wheel outer diameter: 200. .

As a test, the refractory bricks W were placed on a trolley 4 as shown in Figure 3.
Grinding was carried out under the following conditions by placing it on the machine and moving it in the direction of arrow A, and cutting the wheel 3 in the direction of arrow B as shown in FIG.

Wheel circumferential speed = 85 am 7 min Depth of cut: 1 Work material feed rate: 20 Oram/1 nit As a result of this test, it was confirmed that the amount of wear of the tip of the present invention was reduced by about % compared to the conventional tip. .

<Example 2> Average particle size: 2μ artificial diamond fine powder and average particle size:
Using 0.1μ nickel powder as a raw material powder, a mixed powder consisting of 28% nickel powder, artificial diamond fine powder, and the remainder of unavoidable impurities is mixed in the usual manner.
A compacted powder is heated to a temperature of 1450°C and a pressure of 60k.
Sintering was performed under conditions of b1 holding time: 60 minutes, diameter: 1
5, a diamond sintered body with a thickness of 210 mm was obtained, and this was crushed with a Ryotater to give an average particle size of 2.5 mm.
A diamond support of mm was obtained. Then, two inner nickel layers 05 are applied to this diamond support by electroless plating.
μ, outer layer: A multi-layer coating of 0.5μ cobalt layer is applied, and then the metal-coated diamond support is used as abrasive grains, and copper, tin, and iron are used as binders in the same way as with normal chips, and the temperature Pressure sintering was carried out under the conditions of: 900°C, 1 pressure 650°C and a holding time of about 1 minute to create a chip with a length of 01 nm and a width of 3% and a height of about 300 cm. As shown in Fig. 6, the chips used as the grinding chips 1' were brazed to a steel base metal 2' at equal intervals along the circumferential direction, and a wheel 3' as shown below was prepared and used for testing. did.

Wheel shape: Segment type Number of chips installed: 28 Wheel outer diameter: 400 mm As a test, refractory bricks W were placed on a trolley 4 as shown in Figure 7.
The specimen was moved in the direction of arrow A, and wet cutting was performed under the following conditions.

Wheel peripheral speed: 1380771/m depth of cut
As a result of this test, it was confirmed that the wear amount of the tip of the present invention was reduced to about 1/3 compared to the conventional tip.

<Example 3> Average particle size: 3μ artificial diamond fine powder and average particle size:
Using cobalt powder of 0.1μ and nickel powder of average particle size: 01μ as raw material powders, a mixture consisting of 5% cobalt powder, 3% nickel powder, artificial diamond fine powder, and the balance of unavoidable impurities is prepared in the usual manner. The powders are mixed to form a green compact, which is heated to a temperature of 1550°C and a pressure of 65.
Sintering was performed under the conditions of kb1 holding time = 40 minutes, diameter =
A diamond sintered body with a thickness of 15 mms: 10 mm was obtained, and this was crushed by a grinder to obtain a diamond-bearing body with an average particle size of 2 blades. Then, the same multilayer coating of nickel and cobalt as in Example 2 was applied to this diamond support, and on top of that, TiC: 1 μm was coated by PVD.
and then coat the metal and Ti in this way.
C composite coating applied! Diamond rings were used as abrasive grains, copper, tin and iron were used as binders in the same way as for ordinary chips, and pressure sintered at a temperature of 950°C, 1 pressure crab of 300'Yl', and a holding time of 10 minutes. A chip having a length of 30 mm, a width of 5.5 mm, and a thickness of 5 mm was prepared. Next, using this chip, a wheel similar to that in Example 1 was created and subjected to a test.

As a test, the same grinding as in Example 1 was performed under the following conditions.

Wheel circumferential speed: 1500m/Dark depth of cut: 5mm Work material feed rate: 500/Tensing test results confirmed that the wear resistance of the tip of the present invention was reduced by approximately % compared to the conventional tip. 0 <Test Example 4> Diamond fine powder: 1~10μ Cobalt: 5~・10vod% Sintering conditions for diamond sintered body Temperature: 1450~1650℃ Pressure crab 55kb~70kb Sintering time: 30 minutes Like this Under sintering conditions, diameter 15g, thickness 5-10
A round diamond ring was obtained, which was crushed by an attritor to obtain diamond particles having a size of 1 to 3 mm. The diamond particles were used as abrasive grains and used as a metal powder dispensing agent and sintered at high temperature under the following conditions to form a cup-shaped diamond chip having a length of 30 m'Rz 55u1 and a height of 3 mm.

Sintering conditions Temperature near 00℃ Pressure = 300 ~ 8:5 minutes during sintering The diamond chips made in this way are mounted on a steel base metal 2 as shown in the figure at equal intervals along its circumferential direction. Ta.

Shape of the wheel Two-cup type Diamond tips are installed in the number (N): 12 Diamond tips are installed in the position: Ioo distance from the center of rotation of the wheel.

Then, the wheel to which the diamond chip was attached was rotated at a circumferential speed of 8507 H/mM, and the refractory bricks were ground using a cart 4 as shown.

Wheel circumference M: V=+850 HH/m'vt Grinding speed: Depth of cut t2 UmmX Work material feed f2 2000/
As a result of the above tests, it was confirmed that the amount of wear of the wheels of the present invention was reduced to about 1/3 compared to conventional wheels.

<Test Example 5> Composition of diamond sintered body Artificial diamond fine powder: 1~10μ Nickel: 5~jOvoe% Sintering condition temperature of diamond sintered body: 145C1~1650℃ Pressure crab 55kb~70kb 'M during sintering: Under these sintering conditions for 30 minutes, a diameter of 15 grams and a thickness of 5 to 10
A diamond ring having a diameter of 1 mm was obtained, and the diamond ring was crushed by an attritor to obtain diamond particles having a size of 1 to 3 mm.

The diamond particles were then coated using a wet method.

Coating material 2N1,C.

Coating thickness: approx. 1μ After that, these diamond particles were used as abrasive grains and metal powder was used as a binder and sintered at high temperature under the following conditions, and the size was 40 mm in length and T) in thickness. 3mms width (X
) A 7 mm diamond chip 2 was formed O Sintering conditions Temperature near 00°C Pressure crab 3 They were installed at equal intervals along the direction.

Wheel shape: Segment type Number of chips installed: 28 Wheel outer diameter: 400 mm Then, the wheel with the diamond chips attached in this way was rotated, and using the cart 3 as shown in the figure, it was tested under the following conditions. Grinding of refractory bricks was carried out.

Wheel circumferential speed: 1580 m/Water depth of cut: 120 mm Work material feed rate: 500 H/min As a result of the above tests, the amount of wear of this diamond grinding wheel was reduced by about % compared to conventional ones. was confirmed.

[Brief explanation of the drawing]

Drawing G shows Embodiment-1 of the present invention. Figure 1 is a cross-sectional view of a cup-shaped wheel, Figure 2 is an enlarged partial plan view thereof, and Figure 3 is a schematic side view showing its usage condition. , FIG. 4 is a schematic plan view showing its use. Also,
Fig. 5 is a joint cross-sectional view of a segment type wheel, Fig. 6 is an enlarged perspective view of the segment, Fig. 7 is a schematic side view showing its usage state, and Figs. 8 and 9 are a conventional wheel and a wheel according to the present invention. It is a figure which shows the comparative example of the performance with a wheel. 1.1'... Chip, 2.2'... Steel base metal, 3.3'... Wheel, 4... Dolly,
W... Firebrick. Fig. 8 Machining #Hikari i Machining #Grinding l

Claims (3)

[Claims] (1) A diamond wheel for machining hard and brittle materials, characterized in that the abrasive grains are granular diamond rings obtained by crushing a diamond sintered body synthesized under high temperature and high pressure. (2) The diamond wheel for machining hard and brittle materials according to claim 1, wherein a metal plating coating layer is formed on the granular diamond ring body. (3) A coating layer of metal plating is formed on the granular diamond ring body, and a coating layer of non-oxide ceramics such as boride, carbide, 1[substance, etc.] is further formed on the granular diamond ring body. Diamond wheel for machining hard and brittle materials.