JPH07164133A - Sliding nozzle for molten steel vessel - Google Patents

Abstract

PURPOSE:To prevent the entrapment of the air into molten steel caused by sucking the air from gap between nozzle plates, in a sliding nozzle arranged at the bottom part of a molten metal vessel. CONSTITUTION:At the bottom part of the molten steel vessel 1, an upper side fixing nozzle plate 21, an intermediate side sliding nozzle plate 22 and a lower side fixing nozzle plate 23 having a penetrating hole for forming a molten steel passage in each nozzle plate, are arranged by piling up to form the sliding nozzle 2 enabling the formation of the molten steel flowing passage 24. Then seal material for sealing the inner part of the molten steel flowing passage 24 from the outside is interposed between the fixing nozzle plates 21, 23 and the sliding nozzle plate 22 so as to surround the penetrating hole for forming the molten steel flowing passage at least at the time of flowing down the molten steel. By this constitution, the air contamination in the molten steel can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding nozzle for a molten steel container which is used to control the amount of molten steel in a molten steel container such as a ladle or a tundish.

[0002]

2. Description of the Related Art As a sliding nozzle used for controlling the flow down or flow down amount of molten steel in a molten steel container such as a ladle or a tundish, for example, as shown in FIG. The upper fixed nozzle plate 21 provided at the bottom of the molten steel container 1, the middle sliding nozzle plate 22 provided below the upper fixed nozzle plate 21, and the lower fixed nozzle plate 23 provided below the upper fixed nozzle plate 21 are stacked.
There is a sliding nozzle 2 having a structure in which a molten steel flow path 24 is formed by a molten steel flow path forming through hole formed in each nozzle plate 21, 22, 23.
Lower nozzle 3 and long nozzle 4 provided in the lower part of 3
Through tundish (when supplying molten steel in ladle) and mold (when supplying molten steel in tundish)
The molten steel 5 is made to flow down inside.

Further, as the sliding nozzle 2,
In addition to the above-mentioned three nozzle plates 21, 22, 23, there are also two nozzle plates.

The nozzle plates 21, 22, and 23 of the sliding nozzle 2 are made of high alumina, alumina carbon, magnesia, which are excellent in high temperature characteristics.
Refractory materials such as magchrome, spinel, and zirconia are used ("Third Edition Iron and Steel Handbook, Vol.
Steelmaking ”October 15, 1979 Issued by The Iron and Steel Institute of Japan, pages 634-635, 795-796
page).

By controlling the flow of the molten steel 5 or the amount of flow of the molten steel 5 by the sliding nozzle 2 as described above, compared with the case of using a conventional stopper of the elevation type,
Problems such as cracking and melting of the stopper head and poor fitting with the nozzle are solved, and the safety of the molten steel 5 injection work is greatly improved.

On the other hand, such a sliding nozzle 2
Then, the high temperature molten steel 5 passes through the molten steel flow passage 24, but a gap may occur between the nozzle plates 21, 22, 23, and when the molten steel 5 passes through the sliding nozzle 2, the molten steel flow passage 24 Since the inside of the molten steel becomes negative pressure, outside air may be sucked into the molten steel flow path 24 through the gap generated between the nozzle plates 21, 22, and 23, and the air is entrained in the molten steel and However, there is a problem that the amount of impurities may increase.

Therefore, in order to solve the problem of the suction of air into the molten steel flow path 24, the sliding nozzle 2 may be sucked by a vacuum pump to be in a depressurized state. Since there is a problem that equipment becomes expensive and maintenance after installation becomes complicated, it is possible to prevent intake of air into the molten steel flow path 24 by a simple and low-cost means. It was a challenge.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and includes a fixed nozzle plate having a through hole for forming a molten steel flow path at the bottom of a molten steel container, and a through hole for forming a molten steel flow path. In a sliding nozzle of a molten steel container in which sliding nozzle plates having holes are stacked, air is sucked into the molten steel flow path through the gap formed between the nozzle plates, and air is entrained in the molten steel It is an object of the present invention to prevent an increase in the amount of impurities in the device at low cost.

[0009]

A sliding nozzle for a molten steel container according to the present invention comprises a fixed nozzle plate having a through hole for forming a molten steel flow path and a sliding nozzle having a through hole for forming a molten steel flow path at the bottom of the molten steel container. In a sliding nozzle in which moving nozzle plates are provided in an overlapping manner, a sealing material is provided between the fixed nozzle plate and the sliding nozzle plate to seal at least the inside of the molten steel flow passage from the outside when the molten steel flows down. It is characterized by that.

In the embodiment of the sliding nozzle of the molten steel container according to the present invention, the fixed nozzle plate and the sliding nozzle plate are provided with sealing material fixing grooves, and the sealing material fixed by the sealing material fixing groove is used for the molten steel. It is possible to have a structure in which the inside of the molten steel flow path is sealed from the outside by surrounding the flow path forming through hole, and in the same embodiment, the thermal expansion coefficient of the sealing material is larger than the thermal expansion coefficient of the nozzle plate. It is also possible to adopt a configuration in which

In the sliding nozzle of the molten steel container according to the present invention, the molten steel container includes a ladle and a tundish, but is not particularly limited.

As the material of the fixed nozzle plate and the sliding nozzle plate, refractory materials such as high alumina, alumina carbon, magnesia, magcro, spinel, and zirconia can be used. It is desirable to select it appropriately according to the circumstances.

Further, it is desirable to use a heat-resistant material having a thermal expansion coefficient larger than that of the nozzle plate as the sealing material. That is, by using a seal material made of a heat-resistant material having a larger coefficient of thermal expansion than the nozzle plate, the slide plate can be easily slid before the molten steel starts to flow, and the molten steel starts to flow and the temperature rises. This is because the amount of thermal expansion of the sealing material is larger than the amount of thermal expansion of the nozzle plates at this time, so that the sealing property with respect to the gap formed between the nozzle plates is further improved.

As such a sealing material, for example, graphite (graphite, graphite) can be used.

FIG. 2 shows an upper fixed nozzle plate 21 which constitutes the sliding nozzle 2 of the molten steel container according to the present invention.
FIG. 4 is a bottom view of the nozzle plate 21 and a plan view of the lower fixed nozzle plate 23. FIG.
3a is provided, and this molten steel flow path forming through hole 2 is provided.
As shown in FIG. 4, rightward U around 1a and 23a
The seal material fixing grooves 21b and 23b having a U-shape are made of a high alumina material, and the seal material 25 made of graphite (graphite) is made into a U shape in the rightward U-shaped seal material fixing grooves 21b and 23b. It is fixed along the letter shape.

FIG. 3 is a plan view and a bottom view of the middle sliding nozzle plate 22 constituting the sliding nozzle 2 of the molten steel container according to the present invention, in which the molten steel flow passage is formed in the portion on the right side of the center. And a through hole 22a for forming the molten steel flow path, and as shown in FIG. A sealing material 25 made of graphite (graphite) is fixed along the U-shape in the sealing material fixing groove 22b.

FIG. 5 shows the upper fixed nozzle plate 21.
FIG. 3 is a plan explanatory view of the sliding nozzle 2 in which the middle sliding nozzle plate 22 and the lower fixed nozzle plate 23 are overlapped with each other.
Molten steel flow path forming through holes 21a, 23 formed in Nos. 1 and 23
It shows a state in which a and the molten steel flow path forming through hole 22a formed in the sliding nozzle plate 22 are displaced from each other and the flow of molten steel is blocked.

Next, for example, when the molten steel is flowed down from the ladle to the tundish or from the tundish to the mold, the inner sliding nozzle plate 22 is moved to the left in the figure as shown in FIG. The through holes 21a, 22a and 23a for forming molten steel flow paths are made to coincide with each other (in the case of the maximum opening amount), or the through holes 21a, 23a and the through holes 22a are moved.
And are partially matched (when the opening amount, that is, the amount of molten steel flowing down is adjusted), the molten steel flow path 24 having the required opening amount is formed.

At this time, when the molten steel flows down, the inside of the molten steel flow passage 24 becomes a negative pressure. Therefore, in the conventional case, the inside of the molten steel flow passage 24 is exposed from the gap between the nozzle plates 21, 22, and 23. However, in the case of the present embodiment, since the seal material 25 is continuously formed around the through holes 21a, 22a, and 23a, the nozzle plate 21 is not formed. Even if a gap is formed between the molten steel, the molten steel, the outside air is not sucked into the molten steel flow path 24, so that the air is not entrained in the molten steel. Air pollution is avoided.

Further, since the nozzle plates 21, 22, 23 are made of high alumina and the sealing material 25 is made of graphite, which has a larger thermal expansion amount than the alumina,
When the molten steel flows down and reaches a high temperature state, the seal material 25 thermally expands more than the nozzle plates 21, 22, 23. Therefore, when the inner sliding nozzle plate 22 slides, that is, when the sliding temperature is low, the sliding movement occurs. Moving nozzle plate 22
Has a small sliding resistance, and the sealing material 25 is more thermally expanded at a high temperature and the sealing property is further improved.

In the above embodiment, the case where the sliding nozzle 2 is composed of the three nozzle plates 21, 22 and 23 has been described, but the present invention is not limited to this.

[0022]

In the sliding nozzle of the molten steel container according to the present invention, a seal material is interposed between the fixed nozzle plate and the sliding nozzle plate to seal the inside of the molten steel flow passage from the outside at least when the molten steel flows down. Because of the configuration, when a negative pressure is generated in the molten steel flow passage when the molten steel is flowing, even if a gap is formed between the nozzle plates, air is sucked into the molten steel flow passage through the gap. It is possible to prevent the air from being entrapped in the molten steel and to reduce the air pollution of the molten steel.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing a structural example of a sliding nozzle provided at the bottom of a molten steel container.

FIG. 2 is a bottom view of an upper fixed nozzle plate and a plan view of a lower fixed nozzle plate.

FIG. 3 is a plan view and a bottom view of a middle sliding nozzle plate.

FIG. 4 is a cross-sectional explanatory view of a portion in which the sealing material is fixed in a sealing material fixing groove formed in the nozzle plate.

FIG. 5 is a plan view of a sliding nozzle in a nozzle closed state in which an upper fixed nozzle plate, a middle sliding nozzle plate, and a lower fixed nozzle plate are overlapped with each other.

FIG. 6 is an explanatory plan view of the sliding nozzle in a nozzle open state in which the molten steel passage forming through holes formed in the nozzle plate are aligned with each other.

[Explanation of symbols]

 1 Molten Steel Container 2 Sliding Nozzle 5 Molten Steel 21 Upper Fixed Nozzle Plate 21a Molten Steel Flow Channel Forming Through Hole 21b Seal Material Fixing Groove 22 Middle Sliding Nozzle Plate 22a Molten Steel Flow Channel Forming Through Hole 22b Sealing Material Fixing Groove 23 Bottom Side fixed nozzle plate 23a Molten steel flow path forming through hole 23b Seal material fixing groove 24 Molten steel flow path 25 Seal material

Claims (3)

[Claims] 1. A sliding nozzle for a molten steel container, wherein a fixed nozzle plate having a through hole for forming a molten steel flow path and a sliding nozzle plate having a through hole for forming a molten steel flow path are provided at the bottom of the molten steel container in an overlapping manner. A sliding nozzle for a molten steel container, wherein a sealing material is provided between the fixed nozzle plate and the sliding nozzle plate to seal the inside of the molten steel flow passage from the outside at least when the molten steel flows down. 2. A fixed nozzle plate and a sliding nozzle plate are provided with a groove for fixing a sealing material, and a sealing material fixed by the groove for fixing a sealing material surrounds a through hole for forming a molten steel channel to form a molten steel channel. The sliding nozzle for a molten steel container according to claim 1, wherein the inside is sealed from the outside. 3. The sliding nozzle for a molten steel container according to claim 1, wherein the sealing material has a coefficient of thermal expansion larger than that of the nozzle plate.