JP2021139594A - Method for producing refractory block, and refractory block - Google Patents

Abstract

To provide a method for producing a refractory block capable of smoothing the surface of a refractory block.SOLUTION: Refractory raw material 9 put into a container 1 is vibrated by a vibration device, and the refractory raw material 9 in the container 1 is deaerated. The deaerated refractory raw material 9 is charged from the container 1 into a flask 2 having an input port 8 for raw material at the side or bottom. In the flask 2, the refractory raw material 9 is charged from the bottom to top substantially under no-vibration.SELECTED DRAWING: Figure 3

Description

The present invention relates to a method for manufacturing a refractory block and a refractory block.

Conventionally, there has been known a method for manufacturing a refractory block in which a refractory raw material, which is an amorphous refractory, is poured into a mold to manufacture a refractory block, which is a standard refractory. The refractory raw material hardens in the mold to form a refractory block. After curing, the refractory block is removed. This refractory block manufacturing method is characterized in that it is possible to manufacture a free-form integrated refractory block that cannot be formed by brickwork.

As the mold, a mold, a wooden mold, a styrofoam mold, a resin mold, or the like (a mold made of a resin block) is used. Compared to Styrofoam molds, molds, wooden molds, and resin molds have a relatively smooth surface, so the advantage is that the surface of refractory blocks manufactured using molds, wooden molds, and resin molds is also smooth. There is. On the other hand, when manufacturing a refractory block having a reverse taper or a complicated shape, it is necessary to use a split mold, so that there is a drawback that the seam of the split mold is transferred to the refractory block.

Since the Styrofoam mold can be unframed by breaking the mold, it can be integrated even with a reverse taper or a complicated shape, and there is an advantage that the seam of the mold is not transferred to the refractory block. On the other hand, since the surface of the mold is rough, the surface of the refractory block is also rough.

On the other hand, when pouring the refractory raw material into the mold, the refractory raw material is poured while vibrating the mold with a vibration table, or a rod-shaped vibrator is inserted into the refractory raw material poured into the mold to vibrate the refractory raw material. (See, for example, Patent Document 1). In this way, by vibrating the refractory raw material in the mold and degassing the refractory raw material in the mold (removing air bubbles in the refractory raw material), uneven bubble marks on the surface of the refractory block. Can be prevented and the surface of the refractory block can be smoothed.

Jikkenhei 3-84107 Gazette

The smoothness of the surface of the refractory block affects the quality of the products manufactured using the refractory block. For example, in the case of a refractory block for tundish (pouring nozzle), if the inner surface of the pouring nozzle is smooth, the flow of molten metal flowing on the inner surface is stable, and it is manufactured by a casting machine downstream of the pouring nozzle. Products are of high quality.

In order to smooth the surface of the refractory block, it is conceivable to use a mold for the mold and vibrate the refractory raw material filled in the mold with a vibrating device. However, even in this way, there is a limit to smoothing the surface of the refractory block.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for manufacturing a refractory block and a refractory block capable of smoothing the surface of the refractory block.

In order to solve the above problems, in one aspect of the present invention, the refractory raw material put into the container is vibrated by a vibrating device to degas the refractory raw material in the container, and the degassed refractory raw material is used. This is a method for manufacturing a refractory block in which a refractory block having a raw material input port on the side or bottom of a container is filled from the bottom to the top of the mold with substantially no vibration.

In another aspect of the present invention, in a method for manufacturing a refractory block in which a refractory raw material is poured into a mold, a mold in which at least a part of the mold is made of a foam and a resin layer is coated on the mold body is used. This is a method for manufacturing a refractory block.

In still another aspect of the present invention, in a refractory block having a surface in contact with molten metal, there are no bubbles of 1 mm or more on the surface, and the arithmetic mean roughness (Ra) of the surface roughness curve is 5 μm or less. It is a refractory block.

According to the present invention, the surface of the refractory block can be smoothed, and the product manufactured by using the refractory block can be of high quality.

It is a figure which shows the refractory block manufacturing apparatus used in the refractory block manufacturing method of 1st Embodiment of this invention. It is sectional drawing of the formwork. It is a process drawing of the manufacturing method of the refractory block of the 1st Embodiment of this invention. 6 is a graph showing the effect of the arithmetic mean roughness (Ra) on the surface of the formwork on the number of bubbles generated on the surface of the refractory block. It is a graph which shows the influence which the filling rate of a refractory raw material has on the number of bubbles generated on the surface of a refractory block. It is a figure which shows the refractory block (the pouring nozzle) manufactured by the manufacturing method of the refractory block. It is a process drawing of the manufacturing method of the refractory block of the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can be embodied in various forms and is not limited to the embodiments described herein. The present embodiment is provided with the intention of allowing those skilled in the art to fully understand the invention by adequately disclosing the specification.
(First Embodiment)

FIG. 1 shows a refractory block manufacturing apparatus used in the refractory block manufacturing method of the first embodiment of the present invention. 1 is a container, 2 is a formwork, 3 is a passage, 4 is a cock, and 5 is a vibration table as a vibrating device.

The container 1 has a cylindrical shape. An input port 1a for a refractory raw material is provided in the upper part of the container 1. A discharge port 1b for a refractory raw material is provided at the bottom of the container 1.

The formwork 2 has a shape suitable for forming a refractory block. The mold 2 includes an inner mold 2a which is a core and an outer mold 2b. The outer surface of the inner mold 2a is formed in a taper whose outer diameter narrows downward. The inner surface of the outer mold 2b is formed in a taper whose inner diameter narrows downward. The shape of the formwork 2 can be appropriately changed according to the shape of the refractory block. As shown in FIG. 6, the refractory block of the present embodiment is a pouring nozzle 7 for tundish. The surface of the inner mold 2a is transferred to the inner surface 7a of the pouring nozzle 7 through which the molten metal flows.

As shown in FIG. 2, as the inner mold 2a, a mold in which a resin layer 2a2 is coated on a mold body 2a1 made of foam such as hard urethane foam, polypropylene foam, phenol foam, and styrofoam is used. The resin layer 2a2 is formed by applying a coating agent to the mold body 2a1 by spraying or the like. Before applying the coating agent, the filling may be applied to the mold body 2a1. The coating agent may be applied to the mold body 2a1 in one layer, or may be applied in two or more layers. Further, in order to improve the smoothness of the applied coating, a polishing step may be added. For example, when coating a rigid urethane foam, a polyester putty for sealing can be applied to the first layer, and a urethane paint can be applied to the second layer as a coating agent. An unsaturated polyester resin that does not have the effect of dissolving the resin can be applied.

The arithmetic mean roughness (Ra) of the surface roughness curve of the inner mold 2a is 5 μm or less. By coating the resin layer 2a2 on the mold body 2a1 made of foam, an inner mold 2a having an arithmetic mean roughness (Ra) of a roughness curve of 5 μm or less can be obtained. The arithmetic mean roughness of the roughness curve is specified in JIS B0601-2013. The method and procedure for evaluating the surface texture are specified in JIS B0633-2001. A stylus type surface roughness measuring instrument is used as the measuring instrument. If the resin layer 2a2 is coated on the mold body 2a1 of the rigid urethane foam, the arithmetic mean roughness (Ra) can be further reduced as compared with the case where the resin layer is coated on the expanded polystyrene. Therefore, it is preferable to coat the mold body 2a1 of the rigid urethane foam with the resin layer 2a2.

For the outer mold 2b, a mold in which one or more of a mold, a wooden mold, a resin mold, and a foam mold (Styrofoam mold, etc.) are used is used depending on the required surface performance.

As shown in FIG. 1, a charging port 8 is provided on the side or bottom of the mold 2. The input port 8 is preferably provided at a portion of 1/2 or less of the height h of the mold 2.

The container 1 and the formwork 2 communicate with each other by the passage 3 (the container side passage 3a and the formwork side passage 3b). The passage 3 is provided with a cock 4 as an opening / closing means for opening / closing the passage 3. When the cock 4 is opened, the refractory raw material of the container 1 can be moved to the mold 2. When the cock 4 is closed, the movement of the refractory raw material is prevented.

The vibration table 5 vibrates the container 1 with a vibration intensity of, for example, 0.5 G to 1 G. Instead of the vibrating table 5, or in addition to the vibrating table 5, a rod-shaped vibrator inserted into the refractory raw material may be used.

A method for manufacturing the refractory block of the present embodiment will be described with reference to FIG. As shown in FIG. 3A, first, the cock 4 is closed, and the refractory raw material 9 is charged into the inlet 1a of the container 1 while vibrating the container 1 by the vibration table 5 (see FIG. 1).

The refractory raw material 9 is made by kneading a castable and a solution as in the conventional case. The castable is mainly composed of refractory aggregate and fine powder, and also contains a binder and a dispersant. As the solution, water, colloidal silica solution, or the like can be used. A hardening modifier may be added to adjust the pot life of the refractory raw material. As the refractory aggregate, fine powder, binder, dispersant, and hardening modifier, those used in the conventional castable for pouring can be used.

When the refractory raw material 9 is charged from the inlet 1a of the container 1, the refractory raw material 9 entrains air, and bubbles 11 are generated in the refractory raw material 9. The refractory raw material 9 in the container 1 is vibrated by the vibration table 5 to degas the refractory raw material 9 (remove air bubbles 11 in the refractory raw material 9).

Next, as shown in FIG. 3B, the cock 4 is opened, the container 1 and the mold 2 are communicated with each other, and the refractory raw material 9 in the container 1 is transferred from the container 1 to the mold 2 from below the mold 2. Fill upwards. When the refractory raw material 9 is filled in the mold 2, the vibration table 5 is stopped to put the mold 2 in a vibration-free state.

Depending on the shape of the mold 2, a partial flow of the refractory raw material 9 or a horizontal flow may occur. The refractory raw material 9 may be filled from the bottom to the top of the mold 2 as a whole. Further, in order to improve the fluidity of the refractory raw material 9 in the mold 2, the mold 2 may be subjected to a micro-vibration having a strength smaller than the vibration strength when the container 1 is vibrated. The "substantially vibration-free" of the present invention also includes such micro-vibration.

When the refractory raw material 9 is filled from the upper part of the mold 2, the refractory raw material 9 entrains air. As shown in FIG. 3B, this can be prevented by filling the refractory raw material 9 from below to above the mold 2. Further, by filling the mold 2 with the refractory raw material 9 substantially without vibration, it is possible to prevent the fine bubbles contained in the refractory raw material 9 from gathering and generating large bubbles.

As shown in FIG. 3B, when the refractory raw material 9 is filled into the mold 2 from below to above against gravity, the mold 2 and the refractory raw material 9 are caught by the refractory aggregate or the mold 2. An air film may be formed between the refractory material 9 and the refractory material 9, and uneven bubble marks may be generated on the surface of the manufactured refractory block 7. In the present embodiment, the arithmetic mean roughness (Ra) of the surface roughness curve of the mold 2 is set to 5 μm or less, and the filling speed of the refractory raw material 9 in the height direction of the mold 2 is 100 mm / min to 1000 mm / min. By setting to, it is possible to prevent the mold 2 from being caught by the refractory aggregate and the formation of an air film between the mold 2 and the refractory raw material 9. In setting the filling speed of the refractory raw material 9, the refractory raw material 9 in the container 1 is pressurized (for example, a weight is placed on the entire upper end surface of the refractory raw material 9) to adjust the filling speed.

FIG. 4 shows the result of examining the influence of the arithmetic mean roughness (Ra) on the surface of the mold 2 on the number of bubbles generated on the surface of the refractory block 7. The pouring nozzle 7 shown in FIG. 6 is used for the refractory block 7, and the number of bubbles of 1 mm or more generated on the inner surface 7a of the pouring nozzle 7 is counted. The filling rate is 150 mm / min. As shown in FIG. 4, when Ra is 6 to 10 μm, the larger the Ra, the larger the number of bubbles. When Ra is 5 μm or less, bubbles of 1 mm or more are not generated on the surface of the refractory block 7. Since the surface of the mold 2 is transferred to the surface of the refractory block 7, the smaller the Ra of the mold 2, the better, but the manufacturing of the mold 2 becomes difficult. The optimum Ra of the mold 2 is 5 μm or less, preferably 2 μm or less.

FIG. 5 shows the result of examining the influence of the filling speed of the refractory raw material 9 on the number of bubbles generated on the surface of the refractory block 7 when the mold 2 having Ra of 2 μm is used. Similar to FIG. 4, the refractory block 7 uses the pouring nozzle 7 shown in FIG. 6 to count the number of bubbles of 1 mm or more generated on the inner surface 7a of the pouring nozzle 7. As shown in FIG. 5, when the filling rate is less than 100 mm / min, bubbles of 1 mm or more are generated. When the filling speed is 100 mm / min or more, bubbles of 1 mm or more are not generated. Even if the filling rate exceeds 250 mm / min, bubbles of 1 mm or more are not generated. The faster the filling rate, the heavier the weight needs to be. The optimum filling speed is 150 mm / min to 250 mm / min.

As shown in FIG. 3, when the filling of the refractory raw material 9 into the mold 2 is completed, the cock 4 is closed, and the refractory raw material 9 is cured and cured in the mold 2 as in the conventional case.

After the refractory block 7 is cured, the refractory block 7 is fired to burn out the mold 2. The mold 2 may be shrunk and removed by heating. In addition, the formwork 2 may be destroyed. The "burnout" of the present invention also includes "heating / shrinkage" and "destruction". After the formwork 2 is burnt down, the refractory material filled in the formwork side passage 3b (see FIG. 1) is cut off.

In the present embodiment, the formwork 2 is not burnt down and the formwork 2 is not reused. When the mold 2 is reused, it is necessary to apply a mold release agent such as oil to the surface of the mold 2. As a result of the experiment, it was found that when the mold release agent was applied to the mold 2, the wettability was deteriorated due to the water repellency of the mold release agent, and bubbles were generated on the surface of the refractory block 7. This can be prevented by burning the mold 2 without applying a release agent to the mold 2.

FIG. 6 shows a pouring nozzle 7 which is a refractory block manufactured through the above steps. FIG. 6A is a plan view of the pouring nozzle 7, and FIG. 6B is a vertical cross-sectional view of the pouring nozzle 7. Molten metal flows on the inner surface 7a of the pouring nozzle 7. The surface of the inner mold 2a is transferred to the inner surface 7a of the pouring nozzle 7. There are no bubbles of 1 mm or more on the inner surface 7a of the obtained pouring nozzle 7, and the arithmetic mean roughness (Ra) of the roughness curve of 7a on the inner surface of the pouring nozzle 7 is 5 μm, preferably 4 μm or less. be. The arithmetic mean roughness of the roughness curve is specified in JIS B0601-2013. The method and procedure for evaluating the surface texture are specified in JIS B0633-2001. A stylus type surface roughness measuring instrument is used as the measuring instrument.
(Second Embodiment)

FIG. 7 is a schematic view of a method for manufacturing a refractory block according to a second embodiment of the present invention. The mold 2 has substantially the same configuration as the mold 2 shown in FIG. 1 except that the input port 12 is provided on the upper portion of the mold 2. Therefore, the same reference numerals are given to explain the description. Omit. In the second embodiment, the refractory raw material 9 is charged from the charging port 12 at the upper part of the mold 2 while vibrating the mold 2 with a vibration table or the like or without vibration. After the refractory raw material 9 is cured, the refractory block 7 is fired to burn out the mold 2.

In the second embodiment, although bubbles of 1 mm or more may be generated on the surface of the refractory block 7, since the surface of the mold 2 is transferred to the surface of the refractory block 7, the refractory block 7 is used. The surface of the can be smoothed.

In the first and second embodiments, the example in which the pouring nozzle 7 is manufactured as the refractory block 7 has been described. However, as the refractory block 7, a crucible such as a hot metal flowing from a blast furnace and a converter Distributors such as distributors through which molten steel flows from a furnace or ladle, tundish or crucible for storing molten metal, and the like may be manufactured.

Using the manufacturing apparatus shown in FIG. 1, the pouring nozzle 7 shown in FIG. 6 was manufactured according to the manufacturing method of the first embodiment. The particle size composition of the castable refractory aggregate and fine powder is 10% for 1 mm or more and 90% for less than 1 mm. The chemical composition of the castable refractory aggregate and fine powder is 40% _{SiO 2 and} 50% _{ZrO 2.}

The arithmetic mean roughness (Ra) of the surface of the inner mold 2a was 0.5 to 1.5 μm, and the filling speed of the refractory raw material 9 in the height direction of the mold 2 was 150 mm / min. There were no bubbles of 1 mm or more on the inner surface 7a of the pouring nozzle 7. The surface of the inner mold 2a is transferred to the inner surface 7a of the pouring nozzle 7, and although there is a slight increase in surface roughness due to the particle size composition of the refractory material, the arithmetic mean of the inner surface 7a of the pouring nozzle 7 The roughness (Ra) was 1 to 2.5 μm.

1 ... Container 2 ... Formwork 2a1 ... Formwork body 2a2 ... Resin layer 5 ... Vibration table (vibration device)
7 ... Pouring nozzle (refractory block)
8 ... Formwork inlet 9 ... Refractory raw material

Claims (8)

The refractory raw material put into the container is vibrated by a vibrating device to degas the refractory raw material in the container.
A method for manufacturing a refractory block in which a degassed refractory raw material is filled from a container into a mold having a raw material input port on the side or bottom from the bottom to the top of the mold with substantially no vibration. The method for manufacturing a refractory block according to claim 1, wherein a formwork in which a resin layer is coated on a formwork body made of foam at least a part of the formwork is used. The method for manufacturing a refractory block according to claim 1 or 2, wherein the filling speed of the refractory raw material in the height direction of the mold is set to 100 mm / min to 1000 mm / min. In the method of manufacturing a refractory block in which a refractory raw material is poured into a mold,
A method for manufacturing a refractory block, which comprises using a formwork in which a resin layer is coated on a formwork body made of foam at least a part of the formwork. The method for manufacturing a refractory block according to claim 2 or 4, wherein the formwork is burnt down. The refractory according to any one of claims 2, 4 or 5, wherein the arithmetic mean roughness (Ra) of the surface roughness curve of the mold coated with the resin layer is 5 μm or less. How to make a block. In a refractory block with a surface in contact with molten metal
There are no bubbles of 1 mm or more on the surface,
A refractory block having an arithmetic mean roughness (Ra) of the surface roughness curve of 5 μm or less. The refractory block according to claim 7, wherein the refractory block is a hot water pouring nozzle for tundish.

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