JPS6284866A - Nozzle plate brick and its production - Google Patents

Abstract

PURPOSE:To obtain a uncalcined nozzle plate brick having a smooth sliding surface with ease of production by molding a brick molding having a metallic hoop for reinforcement in a molding tool tightly contacting the sliding surface of the molting with a smooth mold stool. CONSTITUTION:The metallic hoop 6 for reinforcement is mounted to the inside surface of a metallic flask 2 of a molding tool 1 and thereafter a brick forming material of, for example, high alumina-graphite is packed into a molding cavity 4 and is then press-molded by a pressing plate 5. The resultant molding 9 is extruded to the outside of the mold 1 by a bottom plate 3 while the hoop 6 is held mounted to the outside peripheral surface thereof to obtain the nozzle brick molding A having a through-hole 10 for outflow of a molten steel. The molding A is cured in a drying furnace while the smooth surface is held in tight contact with the mold stool 11. The uncalcined nozzle plate brick having the smooth surface is thus obtd. with ease of production.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Application The present invention is directed to receiving, pouring, and
The present invention relates to a slide or 0-tally opening/closing nozzle plate brick used in continuous casting, etc., and a method for manufacturing the same.

As shown in Figure 5, the main parts of the conventionally known nozzle system of this type are two nozzle plates stacked one above the other, one of which is a nozzle plate. By sliding the nozzle plates back and forth relative to the other nozzle plate or by pivoting them around a vertical axis, the through holes for the molten steel discharge formed in these nozzle plates can be opened to coincide with each other. 9, the I/CG is configured to immediately respond to a mismatched interruption. The shape of the slide opening/closing type is shown in FIG. 6, and the rotary opening/closing type is shown in FIG. 7. In Figures 5 to 7, φ
υ is the nozzle plate, the trowel is the through hole for molten steel outflow, and Q is the sliding surface of the nozzle plate.

Although this conventional nozzle system is useful, the nozzle plate brick is a fired product and contains carbon and carbon-containing materials, requiring reduction firing.

Specifically, silicon carbide sheath K brick molded bodies are packed together with coke please, sealed and fired. Therefore, there was a problem in that the actual number of unpacked shells was low, and the firing cost was several times higher than in the case where firing in a sheath furnace was not required.

We are also strongly promoting cost reduction at the site of use.
Rather than replacing the nozzle plate with a new one for each batch of molten steel pouring, the goal is to use the nozzle plate several times or more, and when replacing the upper and lower nozzle plates, the nozzle device is disassembled. Since the nozzle plate brick K has cracks as shown in Figure 8 running in all directions from the through hole for molten steel outflow, a steel plate was installed around the outer periphery of the nozzle plate brick to prevent it from shattering when removed. However, this hoop needs to be shrink-fitted, which is a complicated and costly process.

Furthermore, the sliding surface of the nozzle plate brick requires
Since the allowable range for waviness and unevenness is 20 μm or less, the sliding surface was wet-surface ground using a Thai 177 grindstone, etc., which not only required a large amount of money and time, but also caused damage to the bones in the nozzle plate brick. The large coarse grains in the material were ground and exposed in rows on the sliding surface as shown in Figure 9, which had the disadvantage of coming into contact with and reacting with the molten steel. The purpose is to suppress wetting and reaction with molten steel and slag). In Figure 9, phosphorus is the coarse aggregate.

As a result of repeated research in order to eliminate the drawbacks of the above-mentioned prior art, the present inventors have found that in the field of nozzle-rate bricks, the molding surface of bricks containing graphite, especially MfO-C unburnt bricks, is as smooth as a mirror surface. As it is, it is extremely slippery and dangerous to handle, so we focused on the fact that an anti-slip agent (mainly resin) is applied to the nozzle plate without grinding the slippery molded surface. With the idea of using it as a moving surface, the desired surface of the unburnt brick is placed in close contact with a smooth surface plate without warping, distortion, or waviness, preferably coated with a thin layer of mold release agent such as silicone, and then cured. The inventors have discovered that, by doing so, it is possible to obtain an unfired nozzle plate brick having a sliding surface as smooth as the surface of the surface plate, and have completed the present invention.

That is, the present invention provides (1) a metal hoop for reinforcing bricks in the mold during brick molding, and an unfired slide or 0-tally opening/closing nozzle with the hoop attached to the outer circumferential surface; A nozzle plate brick, characterized in that a molded body of the brick is molded in a state in which the sliding surface of the brick is brought into close contact with a surface plate having a smooth surface, and ■ a mold. A brick molding material and a metal hoop for reinforcing the brick are loaded, the brick is formed, and the brick molded body with the metal hoop for reinforcement is placed on the outer circumferential surface of the resulting brick, and its sliding surface is placed on a smooth surface plate. The present invention relates to a method for producing a nozzle plate brick, which is characterized in that a sliding or rotary opening/closing type nozzle plate brick is obtained from the unfired brick molded body by closely contacting the molded brick with the molded body of the unfired brick.

Materials that can be particularly advantageously applied in the present invention include oxides,
It is desirable that carbon and carbon-containing substances, especially graphite, be included in addition to carbides.

In one aspect of the invention relating to the method, a brick-molding material;
For example, clay made of mullite, sintered alumina, graphite, and phenol resin as a high alumina-graphite molding material is filled into a press mold and molded under high pressure, and after molding, it is removed from the mold. The plate brick molded body is placed with its sliding surface in close contact with the smooth surface of a surface plate, and the surface plate is placed in a drying oven and dried at about 200"C for about 20 hours to form a nozzle plate brick. The resulting product does not require grinding of the sliding surfaces, but in some cases, a liquid containing graphite suspended in lubricating oil may be applied to the sliding surfaces of two nozzle plate bricks to improve the sliding surface of the bricks. A post-processing process may be added in which the surfaces are overlapped and manually rubbed together.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.

Example 1 A mold, for example a press mold as shown in FIG.
) is formed by a mold frame (2) and a vertically movable bottom plate (3) fitted to the frame (2).
), with the pressure plate (5) raised and removed, the brick reinforcement gold J! ]! hoop (6) made of, for example, steel plate
, insert the core bale (7) into the hole (3a) of the bottom plate (3), and place it in the molded cow pit (4). In FIG. 1, (8) is a nest that holds down the hoop (6).

Table 1 Raw materials Particle size Mixing ratio Mullite 1.5-2.5M 15% Sintered alumina 1m or less 20% 0,5 ff or less 30% # 0.074 fl or less 20%
Graphite 0.074ff or less
8% carbon black 28μm or less
2% josia kaolin
5% phenol resin (shiriru type)
After 6% and the raw materials and compounding ratios shown in Table 1 above were molded using a roller mold, the resulting clay was placed in the mold as required. Pressure plate (
5) Pressure mold at a pressure of about 1000 x 9/d. After the molding is completed, the bottom plate (3) is pushed up and the molded body (9) is extruded out of the mold (1), and a nozzle plate is provided with a reinforcing hoop (6) around the periphery and has a through hole for flowing out the molten steel. After a mold release agent such as silicone resin is thinly sprayed on the surface of a steel surface plate whose distortion such as ridges and irregularities is less than 10 μm per 1 m, a mold release agent such as silicone resin is applied. The surface of the nozzle plate brick molded body thus obtained, which will become the sliding surface, is brought into close contact with the surface of the surface plate (see FIG. 2).

Next, this surface plate C11J and the nozzle plate brick molded body were placed in a batch type drying oven, and the temperature was raised from room temperature to about 200°C in about 20 hours, and then heated for about 20 hours under the increased temperature and humidity.
Time to cure.

The sliding surface of the product after cooling was extremely smooth.

When the product according to Example 1 was put to practical use in pouring in a ladle, it withstood several charges.

After use, the product was disassembled from the point where it was used and the sliding surfaces were observed, and it was found that there was little corrosion by molten steel, indicating the superiority of the graphite material. The cut surface of the product is as shown schematically in Figure 3. Since the oxide aggregate does not appear on the surface, it has poor wettability with molten steel and therefore does not react with molten steel, so it is expensive. Shows corrosion resistance.

Example 2 Table 2 Raw material Particle size Mixing ratio Sintered matanesia cleaning force -1,0-2,5ff 20%
(#p098% or more) 〃 1 or less 50% 0.074fl
20% or less Graphite 0.0741 or less 10% Phenol resin (reel type)
External 4% A magnesia-graphite clay having the raw materials and compounding ratio shown in Table 2 above is prepared in the same manner as in Example 1, and molded in the same manner as in Example 1 to produce a product.

The obtained product had extremely good sliding behavior, and when it was put to practical use in an actual furnace (tandash), it had sufficient durability for one-time use.

The product according to the second embodiment is economical as it costs a fraction of the cost of the conventional product described above.

The manner of use of the products of Examples 1 and 2 is shown in Figure 4. In Figure 4, the same reference numerals as in Figures 1 to 2 indicate the same parts, and the upper nozzle plate brick The molded body is fixed, and the lower nozzle plate brick molded body can slide in the left and right directions in the figure. 03 indicates the upper nozzle, and α→ indicates the lower nozzle.

As described above, according to the present invention, the steps of reduction firing, shrink fitting of brick reinforcement tools, and sliding surface grinding can be omitted, and therefore the time required to manufacture nozzle plate bricks is shorter than that of the conventional method. The cost of the fired product is almost equal to that of the original product, resulting in a significant reduction in production costs.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view showing the state of press forming of a product as an example of the method of the present invention, and Fig. 2 shows a state in which a molded nozzle plate brick is placed on a surface plate according to the method of the present invention. An elevational view, FIG. 3 is a sectional view schematically showing the state of aggregate of the product of the present invention, and FIG. 4 is a longitudinal sectional view showing an example of use of the product of the present invention. Figure 5 is a cross-sectional view of the nozzle plate brick combination;
Figure 6 is a sketch of a sliding type nozzle plate brick, Figure 7 is a diagram of a rotary type nozzle plate brick, and Figure 8 is the state of cracks after use of a conventional nozzle plate brick. FIG. 9 is an enlarged sectional view of a conventional nozzle plate brick sliding surface. (1) is the mold during press molding (2) is the mold frame (3) is the bottom plate (4) is the molding element sepity (5) is the pressure plate (6) is the hoop (7) is the core rod
(8) is the nest (9) is the molded body αQ is the through hole θ℃ is the surface plate (2) is the oxide aggregate C
Q is nozzle plate brick molded body (and above)

Claims (2)

[Claims] (1) A metal hoop for reinforcing the brick is installed in the mold during brick molding, and the hoop is attached to the outer circumferential surface of the unfired slide or rotary opening/closing nozzle plate brick. 1. A nozzle plate brick, characterized in that a molded body of the brick is cured while the sliding surface of the brick is in close contact with a surface plate having a smooth surface. (2) Load a brick molding material and a metal hoop for reinforcing the brick into a mold, mold the brick, and place the molded brick with the metal hoop for reinforcement on the outer peripheral surface of the resulting brick with its sliding surface facing up. 1. A method for producing a nozzle plate brick, which comprises curing the unfired brick molded body by bringing it into close contact with a smooth surface plate to obtain a sliding or rotary opening/closing type nozzle plate brick.