JPH04305349A - Method for preventing sliding nozzle from closing - Google Patents

Abstract

PURPOSE:To prevent a nozzle from closing and to surely open naturally by providing an air hole at the stop zone of the nozzle inner wall or the lower plate, exhausting inert gas from the air hole before opening the nozzle and bubbling gas in the nozzle. CONSTITUTION:An air hole is set on the nozzle inner wall or the stop zone of a lower plate 9 on a sliding nozzle provided on the outlet of steel of a tundish or a pot, etc. Gas is bubbled in the nozzle by exhausting inert gas from the air hole before opening the nozzle. Therefore, the nozzle is prevented from closing by solidifying the molten metal and the natural hole opening is executed surely even if the sliding nozzle is in the closed state for the long time. Therefore, the oxygen hole opening can be omitted, and the reduction of the steel quality caused by the mixture of the interleaved matter of oxide or nitride, etc., is not generated, and the safety operation can be attained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing clogging of a sliding nozzle provided at a tap opening of a tundish, ladle, etc.

0002

2. Description of the Related Art If a sliding nozzle is left closed for a long period of time, the molten metal will solidify and become clogged, making it impossible to dispense the melt when the opening is opened. This is especially true for steel types with high viscosity. In order to prevent this problem, the closed nozzle is filled with fillers such as silica sand, granulated iron, whiskers, etc., so that the holes open naturally under the static pressure of the molten metal, but the fillers may sinter. In some cases, a strong sintered layer is formed and pores cannot be opened naturally, and in this case, oxygen cleaning is used to open the pores.

0003

[Problems to be Solved by the Invention] Among the conventional pore-forming methods mentioned above, natural pore-forming lacks reliability, and oxygen pore-forming produces nitrides and oxides containing nitrogen and oxygen, which impairs the quality of steel. There is a problem in that it causes a decline. The present invention is designed to prevent the sliding nozzle from clogging due to solidification of the molten metal, that is, to eliminate the need to open oxygen holes.

0004

[Means for Solving the Problem] To solve this problem, the present invention bubbles an inert gas such as Ar gas within a sliding nozzle. That is, in order to prevent clogging of the sliding nozzle due to solidification of molten metal, the present invention provides a hole in the stop zone of the inner wall of the nozzle or the lower plate, and releases an inert gas such as Ar gas from the hole before opening the nozzle. It is designed to perform bubbling.

[0005]

[Operation] The molten metal in the nozzle is stirred by gas bubbling, preventing solidification. Inert gas has an extremely low specific gravity compared to molten metal, and after bubbling, it floats and disperses. The gas used during gas bubbling is approximately 70 to 80 N, to the extent that no splashing of the molten metal occurs.
1/min.

[0006]

[Embodiment] Fig. 1 shows a sliding nozzle installed in a tundish 1.
A tuyere 2, an upper nozzle 3, and an upper plate 4 made of refractory bricks are vertically connected to each other. A sliding metal frame 5 is disposed below the sliding metal frame 5, and is configured to reciprocate in the left-right direction in the figure from a hydraulic cylinder 6 via a bell crank-shaped lever 7 and a rod 8.

The sliding metal frame 5 is further provided with a lower plate 9, an intermediate nozzle 10, and a lower nozzle 11 arranged vertically, and a long nozzle 12 leading to a mold (not shown) is arranged below the lower nozzle 11. has been done. The lower plate 9 is shown in Figure 2.
As shown in FIG. 2, a porous ring 13 connected to a coupler 15 is provided on the lower side, and has pores 14 opening upward from the porous ring 13 to the stop zone.

As shown in FIG. 1, when the sliding nozzle is closed and the tundish is filled with molten steel, Ar gas flows from the coupler 15 through the porous ring 13 and through the pores 14 above the stop zone. It is released into the nozzle hole. Then, the molten steel in the nozzle hole is stirred by bubbling. After bubbling as described above continues for several minutes, the sliding metal frame 5 is moved to the right in FIG. 1 by the hydraulic cylinder 6 and fully opened, allowing the molten steel to flow out through natural openings.

In the embodiment described above, the gas is emitted from the stop zone of the lower plate 9, but in another embodiment, the inner wall of at least one of the tuyere 2, the upper nozzle 3 and the upper plate 4 is released. A pore is provided in the pores, and immediately before or until the nozzle is opened,
Gas is released.

0010

[Effects of the Invention] According to the present invention, even if the sliding nozzle is kept closed for a long time due to variations in operation, it is possible to prevent the nozzle from clogging due to solidification of molten metal and ensure natural opening. Since oxygen pores are not required, there is no deterioration in the quality of steel due to the inclusion of inclusions such as oxides and nitrides, and safe work can be ensured.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of a sliding nozzle provided in a tundish.

FIG. 2 shows an enlarged sectional view of the lower plate of the sliding nozzle shown in FIG. 1;

[Explanation of sign]

2 tuyere
3 Upper nozzle 4 Upper plate
5 Sliding metal frame 9
Lower plate 1
0 Middle nozzle 11 Lower nozzle
12 Long nozzle 13 Porous ring
14 Stomata 15 Coupler

Claims (1)

[Claims] [Claim 1] In a sliding nozzle installed at a tap opening of a tundish, a ladle, etc., pores are provided in the stop zone of the inner wall of the nozzle or the lower plate, and an inert gas is released from the pores before opening the nozzle. A method for preventing clogging of a sliding nozzle, characterized by performing gas bubbling within the nozzle.