JPH058023A - Method for sealing sliding nozzle hole - Google Patents

Abstract

PURPOSE:To improve natural opening hole ratio of a nozzle by preventing flow-out of granular packing material packed into the sliding nozzle hole and formation of solidified layer due to invasion of molten steel at the time of receiving the molten steel. CONSTITUTION:A exposing surface 7A of the granular packing material 7 is covered with an aluminum plate 9. The aluminum plate 9 is softened and melted with latent heat at the time of receiving the molten steel and further, oxidized and hardened, and a coated layer intensely integrated with the surface of granular packing material, is formed. By this coated layer, the flow-out of granular packing material and the invasion of the molten steel at the time of receiving the molten steel are prevented and the natural opening hole is safely and surely executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sealing a sliding nozzle hole provided in a molten metal container, and more particularly to a sliding nozzle hole provided in a molten steel container or the like in order to prevent clogging of the nozzle hole. The present invention relates to improvement of a method of filling and sealing a filler.

[0002]

2. Description of the Related Art A sliding nozzle provided at the bottom of a molten steel container for adjusting the flow rate is composed of an upper nozzle 1, a fixed plate 2, a sliding plate 3 and a lower nozzle 4, as shown in FIG. By sliding the sliding board 3 hydraulically or electrically, the outflow of molten steel is adjusted or stopped.
In the figure, 5 is a nozzle receiving brick, and 6 is an iron skin of the container.

In such a sliding nozzle, when the molten steel penetrates into the nozzle hole at a relatively low temperature in the early stage of steel receiving, the molten steel solidifies in the hole and prevents the molten steel from flowing out.

For this reason, conventionally, a method has been adopted in which the filler 7 is filled into the nozzle holes of the upper nozzle 1 and the stationary platen to seal the nozzle holes and prevent molten steel from entering. This filling material 7
Flows out together with the molten steel when the nozzle is opened.

Conventionally, fillers to be filled in the nozzle holes in order to prevent the nozzle holes from being blocked in such sliding nozzles include silica sand, silica sand coated with carbon fine powder, and granular fillers such as chromium ore particles and carbon particles. Has been used.

However, with the granular filler filled in the sliding nozzle holes, the upper portion of the granular filler flows due to the initial molten steel flow when the molten steel is charged into the molten steel container.
Alternatively, there is a drawback that molten steel penetrates between particles of the granular filler to form a solidified layer. In particular, when the temperature is high and the residence time is long due to refining outside the furnace, the solidified layer forms a strong sintered layer, and even if the sliding nozzle is opened during molten steel pouring, it will not be broken by the molten steel static pressure, It becomes difficult to open naturally. In this case, it is necessary to open the holes in a dangerous work such as oxygen cleaning, which is extremely disadvantageous.

In order to deal with such a phenomenon, the applicant has filled the nozzle hole with a granular filler, and then the upper part of the filler is filled with a refractory material, a sludge (second powder) and an inorganic binder solution.
The method of coating in 8) of the figure was proposed (Japanese Patent Publication No. 57-33).
091).

A method is also known in which a solid plate (iron plate) is laid at a position in contact with the molten metal, and a granular refractory is filled in the lower part of the plate (JP-A-51-117127).

[0009]

[Problems to be Solved by the Invention] Japanese Patent Publication No. 57-3309
In the method described in Japanese Patent Publication No. 1, the inside of the container is usually 1000 to 12.
Since the ambient temperature is 00 ° C., there is a drawback that a complicated work is required to uniformly coat the surface of the granular filler with the sludge.

Further, according to the method described in Japanese Patent Laid-Open No. 51-117127, it is possible to surely treat the nozzle receiving brick and the upper nozzle when they are new at the initial stage of use, but after continuous use, the nozzle surface becomes uneven. Therefore, it is difficult to bring the iron plate into close contact with the granular refractory.

The present invention solves the above conventional problems,
Prevent the filler in the nozzle hole from flowing by molten steel when receiving steel. It suppresses the infiltration of molten steel into the filler-filled part. Even if the temperature of the molten steel becomes high and the residence time becomes long, the filler and the molten steel can smoothly flow out naturally when the nozzle is opened. An object is to provide a method for sealing a sliding nozzle hole.

[0012]

According to a first aspect of the present invention, there is provided a method of sealing a sliding nozzle hole, the method comprising filling a nozzle hole of a sliding nozzle with a granular filler and sealing the nozzle hole. It is characterized in that the upper surface of the material is covered with an aluminum plate or an aluminum alloy plate.

According to a second aspect of the present invention, there is provided a method for sealing a sliding nozzle hole, wherein the nozzle hole of the sliding nozzle is filled with a granular filler to seal the nozzle hole. Alternatively, it is characterized in that it is covered with a composite plate composed of an aluminum alloy and one or more selected from the group consisting of glass frit, orthoclase, silica and silica-alumina.

That is, as a result of intensive studies conducted by the present inventors in view of the above-mentioned state of the art, it was found that an excellent effect can be obtained by integrally providing an aluminum or aluminum alloy plate on the surface of the granular filler. Heading, completed the present invention.

The present invention will be described in detail below with reference to the drawings. In addition, although the case where it is applied to a molten steel container is described below, it goes without saying that the present invention is also applicable to other molten metal containers.

FIG. 1 is a sectional view showing an embodiment of the present invention. In FIG. 1, members having the same functions as those in FIG. 2 are designated by the same reference numerals.

In the sliding nozzle hole sealing method of the present invention, first, the nozzle hole of the sliding nozzle is filled with the granular filler 7. In this case, it is preferable that the filling layer exposed surface 7A of the granular filler 7 forms a flat surface together with the nozzle receiving brick 5. For this reason, as shown in the figure, the granular filler 7 is provided in the holes 2A of the stationary platen 2 and the holes 1 of the upper nozzle 1.
A, and further, it is filled in the recess 5A of the nozzle receiving brick 5 so that the upper surface 5B of the nozzle receiving brick and the filling layer exposed surface 7A of the granular filler 7 are flush with each other.

Next, an aluminum plate 9 or an aluminum alloy plate or the above composite plate is placed on this surface so as to cover at least the exposed surface 7A of the packed layer of the granular filler 7.

Among the aluminum plates or aluminum alloy plates used in the method of claim 1, the aluminum alloy of the aluminum alloy plate is Al-Si alloy or Al-Ca.
Examples include alloys. Further, the shape thereof may be any of a non-perforated plate shape, a multi-perforated plate shape, an extract band metal shape and the like. The size thereof may be an area (usually about 250 to 500 mm) that covers the entire exposed surface of the granular filler,
The thickness is preferably 0.5 to 7 mm. This thickness is 0.5
If it is less than mm, the strength is low and the material is easily deformed, resulting in poor sealing workability. On the other hand, when the thickness exceeds 7 mm, the solution of aluminum or aluminum alloy permeates to the deep part (lower part) of the granular filler layer, which is not preferable because it becomes an excessively thick integrated layer.

The aluminum plate or aluminum alloy plate covering the granular filler may be a single plate or a plurality of laminated plates.

In the composite plate used in the method of claim 2,
As the glass frit, an amorphous low-melting glass pulverized product (melting point 400 to 110) generally used for producing enamel is used.
A commercially available product can be used at 0 ° C. Further, glass powder such as borosilicate glass, phosphoric acid glass and soda glass having a softening point of 1000 ° C. or lower can be used.

Orthoclase is a rock-forming silicate mineral KAlSi ₂ O
Any potassium feldspar containing ₈ as a main component can be used as long as it is used in the pottery industry and the like.

As silica and silica-alumina, silica sand powder, silica stone powder, clay, wax stone powder, chamotte powder,
Mullite powder, alumina powder and the like can be used.

The above glass frit, orthoclase, silica, silica.
The material of alumina is selected by the molten steel temperature of the molten steel container,
It is appropriately selected according to other operating conditions such as residence time.

Among the aluminum or aluminum alloys constituting the composite plate used in the method of claim 2, the aluminum alloys include Al-Si alloys and Al-Ca alloys, which are plate-shaped and have a plurality of perforations. A plate shape, a plate shape having a plurality of claw protrusions, an extract band metal shape, or the like can be adopted.

The method for producing the composite plate used in claim 2 is not particularly limited. For example, an aluminum plate or an aluminum alloy plate may be sprayed or troweled with glass frit, silica or other sludge, and then dried. Alternatively, by casting and kneading a predetermined kneaded material together with one or more aluminum plates or aluminum alloy plates and drying, it is possible to easily obtain a composite plate that sufficiently withstands the sealing operation. In addition, in order to improve the strength of the composite plate, CMC as a binder was added to the slurry or the kneaded product.
(Carboxymethyl cellulose), PVA (polyvinyl alcohol), lignin sulfonic acid, etc. can also be added.

The size of such a composite plate is such that the entire surface of the exposed surface of the granular filler is covered (usually, the diameter is 250 to 500 m).
m)), and the thickness is preferably 2 to 50 mm. If the thickness is less than 2 mm, the strength is weak and the material is easily deformed, resulting in poor sealing workability. Further, if it exceeds 50 mm, it is too thick and the sealing workability is impaired. The thickness of the aluminum plate or aluminum alloy plate forming the composite plate is 0.
It is preferably 5 to 7 mm.

On the other hand, the granular filler used in the present invention is not particularly limited, and those conventionally used in this field can be used. For example, silica sand, chrome ore particles, alumina particles, zircon particles, carbon particles, etc., whose particle size is in the range of about 0.3 to 2.5 mm, and have a predetermined particle size distribution as necessary. It is possible to use those whose particle size has been adjusted.

By coating or impregnating the carbonaceous material with the above-mentioned granular filler, it is possible to suppress seizure between particles even when exposed to high temperature for a long time.

In the present invention, the granular filler used is 1
Not limited to species, two or more species may be used in combination. For example, a two-layer filling method may be adopted in which the lower part of the nozzle hole is filled with the granular filler having a low thermal conductivity and the upper part of the nozzle hole is filled with the hardly sinterable granular filler.

[0031]

When the aluminum plate or aluminum alloy plate covering the upper surface of the granular filler is sealed, the aluminum or aluminum alloy softens or melts due to the ambient temperature in the molten steel container and adheres to the surface of the granular filler. Further, aluminum is oxidized into aluminum oxide to form a coating layer that is firmly integrated with the granular filler. Similarly,
In the composite plate used in claim 2, after the sealing work is completed, the glass frit is softened and melted by the ambient temperature in the molten steel container,
Further, aluminum or an aluminum alloy is also softened and melted and adheres to the surface of the granular filler, and further, aluminum is oxidized to form aluminum oxide to form a strong integrated coating layer. Therefore, at the time of receiving steel, the coating layer prevents the granular filler from flowing out by the molten steel and suppresses the formation of the infiltration solidification layer of the molten steel.

On the other hand, at the time of pouring molten steel, by opening the nozzle, the natural pressure is rapidly opened by the molten steel static pressure.

[0033]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

Example 1 Silica sand (particle size 0.3 to 1.
7 mm) of granular filler (10 kg) was filled, and an aluminum plate (diameter 400 mm × thickness 5 mm) was coated on the upper portion thereof. The aluminum plate was softened and melted by the latent heat in the molten steel ladle, further oxidized and hardened, and the upper surface of the granular filler was integrated. In this sliding nozzle, when the molten steel residence time from the steel receiving to the start of pouring was 40 to 60 minutes, the natural open area ratio calculated by the following formula was 99%. The natural porosity of the conventional method using the silica sand granular filler alone without using an aluminum plate was 95%.

[0035]

[Equation 1]

Example 2 Instead of the aluminum plate, 50% by weight of glass frit and 50% by weight of silica powder and a perforated aluminum plate (thickness 2
mm) and a composite plate (thickness: 10 mm) was used. The composite plate was softened and melted by the latent heat in the molten steel ladle, and the upper surface of the granular filler was integrated. This sliding nozzle had a natural aperture ratio of 98.5% under the condition that RH treatment was performed for 20 to 25 minutes after receiving the molten steel.

Example 3 Instead of silica sand, zircon sand (particle size 0.1 to 0.5 mm)
Filled with the granular filler (15 kg), the aluminum plate with a plurality of claw protrusions (thickness: 1 m, instead of the aluminum plate)
m) The procedure of Example 1 was repeated except that a composite plate (thickness: 30 mm) sandwiching 30% by weight of glass frit and 70% by weight of orthoclase powder was used between the two sheets. Due to the latent heat in the molten steel ladle, the composite plate was softened and melted and further hardened, and the upper surface of the granular filler was integrated. This sliding nozzle had a natural open area ratio of 98% after a residence time of 60 to 90 minutes under the condition that RH treatment was performed for 20 to 25 minutes.

Example 4 Instead of silica sand, 70% by weight of silica sand (particle size 0.3 to 1.7 mm) and 30% by weight of chrome ore (particle size 0.3 to 1.2 mm)
20% by weight of glass frit and 80% by weight of alumina powder were filled between two aluminum plates with claw projections (thickness 2 mm) instead of the aluminum plate by filling the mixed granular filler (15 kg) with Sanda composite board (thickness 20m
Example 1 was repeated except that m) was used.
The latent heat of the molten steel ladle softens and melts the composite plate, further hardening it,
The upper surface of the granular filler was integrated. About this thing
After receiving the steel, the natural porosity was 99% after performing outside furnace refining at 1680 to 1700 ° C. for 20 to 25 minutes.

[0039]

As described above in detail, according to the sliding nozzle hole sealing method of the present invention, the flow of the filler during the steel receiving and the generation of the solidified layer due to the invasion of the molten steel are effectively suppressed. It has become possible to stably and surely secure the natural opening of the nozzle even after the refining process at a high temperature for a long time as well as the conventional casting.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a method for sealing sliding nozzle holes according to the present invention.

FIG. 2 is a sectional view showing a conventional method.

[Explanation of symbols]

1 Upper nozzle 2 fixed board 3 Sliding board 4 Lower nozzle 5 nozzle receiving bricks 7 Granular filler 9 Aluminum plate

Claims (2)

[Claims] 1. A method for filling a nozzle hole of a sliding nozzle with a granular filler to seal the nozzle hole,
A method for sealing a sliding nozzle hole, which comprises covering an upper surface of the granular filler with an aluminum plate or an aluminum alloy plate. 2. A method for filling a nozzle hole of a sliding nozzle with a granular filler to seal the nozzle hole,
A sliding nozzle characterized in that the upper surface of the granular filler is covered with a composite plate consisting of aluminum or an aluminum alloy and one or more selected from the group consisting of glass frit, orthoclase, silica and silica-alumina. Hole sealing method.