JPS61112604A - Method of molding refractory sheet - 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 [Field of commercial application] This invention relates to a method for press forming thin plates of refractories, such as thin plates having a thickness of 1 to 40 mm.

[Conventional technology and its problems]

Traditionally, casting methods,
Vibratory casting, vibrating press overflow, and -shaft press injection molding methods are used, but in the case of casting, ultrafine powder is added to the particle size surface, which is necessary to develop thixotropic properties, that is, fluidity by imparting vibration. The advantage of increasing the amount of bonds is 1.
Since all parts are received, there is a problem with the quality of the step products, and furthermore, there is a
f! ! ! Due to the severe drop in productivity due to lack of strength during handling until commercialization, the minimum thickness for production was around 10B◇! The vibratory press method has the disadvantages of poor quality due to insufficient filling of the molded body due to extremely low molding pressure, and decreased productivity due to difficulty in handling due to lack of strength of the molded body. My shoulders are cold.

In addition, the conventional uniaxial press forming method using hydraulic pressure is desirable because it has good productivity and allows the adoption of conventional manufacturing methods, but it is not good when the uniformity of the formed object is less than 40 rnA in thickness. , and a large flat area on 200×200WNAu? 'iIt was practically impossible to manufacture.

The reason is as follows. In other words, when press pressure is applied, the filling condition of the clay is 2 L on average in 11 seconds.

Even if a force of 50/- or more is actually consumed at the tip of the grain where stress is concentrated, the grain collapses,
A field with a very high filling rate /-1f occurs locally, and conversely there are places around it where only a small amount of pressure is applied, so if it is made into a product, the strength at that place will be weak and it will become a defective part. This causes cracks to form.

It is necessary for the Rokumasu large-sized material to have uniform strength at all locations, and in order to satisfy this requirement, it is necessary to apply uniform forming pressure to the entire pounded soil.

In addition, when the compaction thickness is thick (approximately 15 times or more of the maximum grain size in the mixed soil), grain movement is observed in the direction of closest packing due to multiple pressurizations. Although it is small, when the molding thickness is thin, the movement of coarse grains is small and the pressure consumption in the coarse grain area is large.This indicates that the pressure distribution around the coarse grains is uneven. This is an unavoidable phenomenon when the press face plate is flat.Therefore, it has conventionally been almost impossible to form a thin plate into an even shape using a uniaxial press.

Conventionally, the rubber press method (isostatic press method or isostatic press method) is a well-known method for obtaining uniformly textured compacts, and is used for molding micro-dense ceramics, small-sized or special-shaped products, etc. It is widely used in This principle of ε is an application of Pascal's law to powder molding, and the powder is filled into an elastic container with low deformation resistance, such as rubber, and gastric fluid pressure is applied in a pressurizer. In addition, the powder is molded through rubber with a pressure equal to the hydraulic pressure on the entire surface to obtain a molded product with a uniform structure.

However, this °method is a general K h9. There are problems in that the forming efficiency is low and the productivity is very low as it requires processing of the molded and fired bodies, and for the same reason, the rubber press method is inappropriate for manufacturing large thin planar shapes.

[-Problem that the invention seeks to solve]

This invention solves the problems of conventional refractory materials such as thin rice ffi and cedar, namely, differences in strength depending on the location of the product due to uneven molding pressure distribution, poor quality, poor seatability, and products with a thickness of 101 or less. By solving problems such as the inability to obtain molded products and the difficulty in manufacturing large flat areas, we can produce high-quality, uniform, and large-sized fire-resistant thin plates using shaft press molding without reducing productivity. A molding method for manufacturing is provided.

[Means for solving problems]

The present invention is an application of the excellent feature of the rubber press method, in which powder and granules can be formed into a uniform structure, to uniaxial press molding. When forming mixed wire or further granulated mixed soil using a loading port, a plate-shaped layer of rubber or the like is placed on both the upper and lower surfaces of the wire filled into the press molding frame so as to cover almost the entire surface of the gravel. An elastic body is inserted and uniaxial press molding is performed. Note that the thickness of the molded body is 30
In the case of a thin plate with a thickness of less than 100 mm, the above-mentioned elastic body is inserted on only one side of the line, either the upper or lower surface, and nibless molding is performed.

[Effect]

FIG. 1 is a longitudinal sectional view of the inside of the press forming frame showing a conceptual diagram of the method of the present invention, and shows the side frame of the single press frame, the bottom plate of the double press frame,
Reference numeral 6 denotes the inserted elastic body, the 4-piece molding frame filled with clay, and the 5-piece lower plate.

That is, a predetermined amount of the dough 4 is poured into the upper part of the lower plate 5, and the elastic body 3 is inserted into the upper surface of the mixture, and then the upper plate 2 and the lower plate 5 are
When uniaxially pressurized at high pressure, the elastic body 3 deforms uniformly in all directions even when the coarse particles in the mixed soil do not move, so the entire mixed soil is press-formed with uniform pressure and a uniform structure is formed. You will gain a body.

It is preferable that the gap between the elastic body 6 and the vertical frame 1 be close to zero by rubbing together, and the material of the elastic body can be soft rubber, hard rubber, etc., but one with a large elastic limit is effective. Soft rubber is most suitable from the viewpoint of durability and durability.

If the thickness of the elastic body is thin (less than 1 W@), damage to the periphery of the elastic body will increase due to repeated use, and the phenomenon of uneven pressure may occur due to insufficient deformation in the thickness direction when applying pressure. This is not preferable because the effect of uniform pressure molding by using a body is reduced. Moreover, if the thickness exceeds 20 m, although the effect of inserting the elastic body is good, the productivity is poor and it is uneconomical.

Therefore, the thickness of the elastic body to be inserted should be 1 to 1 in the case of a soft rubber plate.
20RIl is suitable.

In addition, in order to reduce the entrapment of coarse particles into the elastic body during knife pressure, and to take out the molded body at a high yield without breaking it,
By inserting paper, vinyl paper, cloth, etc. between the elastic body and the clay, the molding and removal operations can be completed more quickly.

This invention exhibits a more effective effect in forming thin plates, and when the forming thickness exceeds 40x, the movement of coarse grains is observed, albeit gradually. There is a tendency for the difference between methods to decrease.

On the other hand, the relationship between the molded thickness and the uniformity of the molded body is greatly influenced by the molded flat area, and in this invention, two
Uniform molding is particularly effective when the flat area is 00 x 200 m or more.

The clay used in this invention is a type of grain or powder of general refractory materials such as silicon, mullite, alumina, chromium, magnesia, zircon, zirconia, silicon carbide, nitrogen (L'silicon, etc.) or 281 or more. A commonly used organic or inorganic binder, moisture, etc. are added to the mixture and the particle size is adjusted, and the mixture is kneaded or granulated to obtain a clay for molding.

〔Example〕

An actual example will be explained in detail below.

Example 1゜Maximum grain 2.0, cumulative grain size 0.044B or less, 20%, 0
．． 297am or less 65%, 0.1- or less 65%, 1.4
Grains consisting of 85% of 1tnJU/! 'Adjustment? To the mullite raw material (mullite value 98.5%), 1.0% @1 binder binder and 2.5% water were added, and the mixture was kneaded for 60 minutes with a universal mixer to form a kneaded soil. I got it. Molding area 3
0[]X30 (lr-1 molding thickness each t'L5 tt
A soft rubber plate having a thickness of 2 mm and 5B was inserted into both the upper surface and the lower surface, only the upper surface, and only the lower surface, and molding was carried out at a molding pressure of 1500/6 nm, 10 wpn, 40 mm, and a molding pressure of 1500/6 I.

In addition, in order to confirm the structure of the compact by location, the compact was fired at 1480°C in a tunnel kiln and divided into 5 equal parts vertically and horizontally in a 60 x 60 square, and from the 25 sections, 5 samples were taken from the same location for each compact. The bending strength was measured. The results are shown in Table 1.

As shown in Table 1, in the case of the conventional method without a rubber plate, the bending strength varies greatly from place to place, and there are very weak parts. And the difference is larger for rods with thinner molding thickness. On the other hand, in the case of products molded by the method of this invention, the variation in bending strength from place to place is very small, regardless of the molding thickness, rubber plate thickness, and rubber plate insertion conditions, and the average value of bending strength is Also, compared to the conventional method, it is slightly larger or larger.

Example 2 Maximum grain size is 20 cm, cumulative grain size is 0.074-30 cm or less, 0.
297 and below 55%, 1. Oa+ or less 80chi, 1.41
To a silicon carbide raw material whose particle size has been adjusted to be 8 or more and 20%, phenolic resin binder (outer layer), metal silicon powder (outer layer), metal silicon powder (outer layer), 5 g. Got the top. With a molding area of 300x300a+s+, a molding surface of J6F, 10m+, and a molding pressure of 1500/,
Molding was carried out by inserting soft rubber plates with a thickness of 5 cm on both the top and bottom surfaces, only on the top surface, or only on the bottom surface.

In order to confirm the structure of the molded product by location, 60% of the book was packed in a tunnel kiln at 1480°C and fired by reduction firing.
The molded body was divided into 5 equal parts vertically and horizontally at a ×60 angle, and from among the 25 pieces, 5 samples were taken from the same location for each molded body, and the bending strength was measured. The results are shown in Table 2.

As shown in Table 2, in the case of the conventional method without a rubber plate, as in the case of Example 1, the bending strength varies greatly depending on the location, and the difference becomes larger as the molding thickness becomes thinner. On the other hand, in the case of products formed by the method of the present invention, there is little variation in bending strength at different locations, almost regardless of the molding thickness and temporary rubber insertion conditions, and the average value of bending strength is also lower than that of the conventional method. Although it is slightly, it is increasing.

〔Effect of the invention〕

As described above, this invention makes it possible to form a large size N with a uniform structure, and compared to conventional methods, all parts of the product are uniform and of good quality. Thin plates can be manufactured with high productivity.

In particular, as shown in the example, in the conventional method, depending on the location of a piece of music, there are parts where the Yaro is very weak.
This part affects the overall quality and makes the product unusable. However, with the method of this invention, the variation in bending strength depending on the location is very small, and the bending strength is very small. The maximum/J% value is also almost the same as the average value of the conventional method.

Furthermore, we were able to obtain a product with a thickness of 10 mm or less, which was almost impossible to mold using conventional methods.

Furthermore, the effects of the method of this invention are to be fully investigated. In Example 2, the pressure distribution on the mixing soil surface with a molding thickness of 51 and a molding pressure of 1500 yurob was changed to a maximum pressure of 1600'C9/
-Measured using pressure-sensitive paper. FIG. 2 is a schematic diagram showing the pressure distribution on the soil surface, where (a) shows the case of the present invention, and (h) shows the case of the conventional method. In the figure, the pressure of the black part is 130 C1'/- or more, and the light black part is 500 C1'/- or more.
The nominal fF pressurized at a pressure of ~1600 kg/6 I is shown, and the white part indicates a part that is under only a low pressure of 500 kg/6 I or less. As a result, when molding is performed using the method of this invention, the entire surface becomes 1300'9/- as shown in Figure (a).
Although the knife-edge pressure is applied with the above pressure, if the rubber plate of the conventional method is not used (as shown in Figure b1, the coarse grain part is 130
On the other hand, the fine powder part is under only a low pressure while it is under a pressure of 0 kg/- or more. In addition, according to Oh + I Chico's invented method, which shows that there is a large pressure difference depending on the location, the entire surface of the drilled soil is evenly pressurized, and after forming, the plate has a uniform structure and is a thin plate of good quality. This was also confirmed by the above-mentioned test.

[Brief explanation of the drawing]

Figure 11 is a vertical cross-sectional view of a circle of a press forming frame showing a conceptual diagram of the present invention, Figure 2 is a schematic diagram showing the pressure distribution on a line when press pressure is applied, and Figure (a) shows the method of the present invention. Figure (b) shows the case using the conventional molding method. In Fig. 1, 1...Side frame, 2...Top plate, 6...Elastic body, 4...
...Practice ±5...Bottom board.

Claims (1)

[Claims] In the case of press-forming a clay made by adding a binder to a refractory raw material whose particle size has been adjusted, a plate-shaped elastic body is placed on both the upper and lower surfaces of the clay filled in the press-forming frame, or on either the upper or lower surface. A method for forming fire-resistant thin plates by inserting and uniaxial press forming.