JPS6120659A - Discharge device for molten metal - Google Patents

Abstract

PURPOSE:To assure the initial opening of a passage hole for a molten metal and the prevention of clogging during casting by providing plural gas supply holes having different sized and communicating with the passage hole to a molten metal passage to a fixe plate consisting of dense refractories and disposing porous refractories to the gas supply side. CONSTITUTION:The upper stationary plate 2 of a discharge device for the molten metal is formed of the dense refractories and a gas supply body 12 is fitted to the center of the body 11. Plural small holes 18, 19 having respectively 0.4- 1.0mm. and 0.1-0.4mm. diameters are alternately provided to the body 12. A pressure equalizing zone 15 is formed between the porous refractories 14 on the outside periphery and a gas introducing hole 16. A large amt. of an inert gas is supplied through the holes 18 into the hole 13 to apply strong stirring force to the molten metal in said hole in the initial opening stage. A proper amt. of the gas is supplied through the holes 19 during casting to prevent the clogging of the hole 13 and to float and remove non-metallic inclusions. The initial opening of the passage hole for the molten metal is thus made easy and the solidification of the molten metal in the passage hole and the sticking of the non-metallic inclusions are surely prevented during casting.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a molten metal discharge device that is attached to the bottom of a ladle or tundish when molten metal is cast.

[Technical background of the invention and its problems] When casting molten steel by the continuous casting method, the molten metal has a fixed plate and a sliding plate in the nozzle at the bottom of the ladle or tundish that accommodates the molten steel. By installing a discharge device and sliding a slide plate relative to a fixed plate, the passage hole for molten steel is opened and closed, and the flow of molten steel is adjusted. For example, when this molten metal discharge device is attached to the upper nozzle at the bottom of the tundish, the upper nozzle will prevent the molten metal from solidifying in the molten metal passage hole of the upper fixed plate when starting to supply molten metal to the mold, and will prevent the molten metal from solidifying during casting. Inert gas is supplied from the upper fixed plate into the molten steel for the purpose of solidifying the metal, preventing the adhesion of non-metallic inclusions (oxides), and removing the oxides by floating them to the top of the molten metal. ing.

Conventionally, a porous refractory was provided on the inner surface of the passage hole of the L fixed plate in order to supply gas during molten steel from the upper fixed plate. However, the gas supplied through the porous refractory has a small bubble diameter, and the stirring force of the molten steel at the time of initial opening is small, so it cannot be said that blockage of the passage hole can be reliably prevented. Furthermore, since it is porous, it has a disadvantage of poor corrosion resistance.

Therefore, in order to eliminate these drawbacks, the upper fixed plate is made of a dense and large material with a small hole of 0.1 to 1.0 mm in diameter or 0.1 to 1 mm in width. It has been proposed to provide slits of 0.0 cm and supply gas into the molten steel through these gas supply holes.

Incidentally, the amount of gas supplied varies depending on the purpose of blowing the gas. For example, for the initial opening of the upper nozzle and upper fixed plate, 1
While a strong stirring force with a gas flow rate of about 00 to 501/l1in is required, it is necessary to use a strong stirring force of 5 to 151/l1in to prevent the passage hole from clogging during casting and to remove nonmetallic inclusions.
It has been confirmed that a gas flow rate of n is effective.

For this reason, if the main purpose is to open the initial opening, it is necessary to supply gas with stirring power, for example, the diameter (or width) is 0.
．． Small holes (or slits) of 4 to 1.0 m+a are provided, and gas is supplied at a flow rate of 100 to 1501/111n. However, during casting, the stoichiometric amount of gas is adjusted to 5 to 151/cm in order to prevent the passage holes from clogging and to remove non-metallic inclusions.
It is necessary to reduce it to 1 inch. If the gas flow rate is reduced in this way, molten metal may enter the gas supply hole and block the gas equalization zone, making it impossible to supply gas, or even causing an accident where molten metal leaks to the outside through the gas introduction hole. Something happened.

On the other hand, if the main purpose is to prevent the passage hole from clogging during casting and remove non-metallic inclusions, for example, a small hole (or slit) with a diameter (or width) of 0.1 to 0.4 mm may be provided. However, if such a relatively small gas supply hole is provided, it is not possible to reliably obtain the strong stirring force required for the initial opening at the time of starting the supply of molten metal to the mold.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and has the following objects: - to ensure the initial opening of the joint hole and the prevention of blockage of the passage hole during casting, the floating removal of non-metallic inclusions, and the removal of molten metal. The object of the present invention is to provide a molten metal discharge device that can effectively prevent accidents such as leakage of molten metal to the outside.

[Summary of the Invention] The molten metal discharging device of the present invention has a fixed plate made of a dense and large-sized material, and has two or more different sizes for supplying gas into the molten metal passage hole inside the fixed plate. It is characterized in that a plurality of gas supply holes are provided and a porous refractory is provided at least on the gas supply side of the relatively large gas supply hole.

According to such a molten metal discharge device, a large amount of gas is discharged from a relatively large gas supply hole (for example, a small hole having a diameter of 0.4 to 1.0 mm or a slit having a width of 0.4 to 1.0 mm). can be supplied to provide a strong stirring force to the molten metal, thereby facilitating the initial opening of the passage hole. In addition, by supplying an appropriate amount of gas through a relatively small gas supply hole (for example, a small hole with a diameter of 0.1 to 0.4 am or a slit with a diameter of 0.1 to 0.4 a + m), it is possible to It is possible to ensure prevention of clogging of the passage hole and floating removal of non-metallic inclusions. Furthermore, since the porous refractory is provided at least on the gas supply side of the relatively large gas supply hole, molten metal will not leak to the outside even if the gas flow rate is reduced.

In addition, in the present invention, the air permeability of the porous refractory is determined by the air permeability and the shape (particularly the thickness), but it is sufficient that l O (1-2001/win) is supplied from the gas supply hole, and there are no particular limitations. Not done.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, a molten metal discharge device (sliding nozzle) 5 consisting of an upper fixed plate 2, a sliding plate 3, and a lower fixed plate 4 is attached below an upper nozzle 1 fixed to the bottom of a tundish (not shown). . The lower fixed plate 4
An immersion nozzle 6 is attached below the mold, and the lower end of the immersion nozzle 6 is immersed in the molten steel 8 in the mold 7.

The upper fixed platen 2 constituting the molten metal discharging device 5 has a structure as shown in FIG. That is, a gas supply body 12 made of a dense refractory is fitted into the center of the upper stationary plate main body 11 made of a dense refractory, and the inside thereof serves as a passage hole 13 for molten metal. A porous refractory 14 is fitted to the lower outer periphery of the gas supply body 12, and a gas pressure equalization zone 15 is formed between the porous refractory 14 and the upper fixed plate body 11. Further, the main body 11 is provided with a gas introduction hole 16 that communicates a part of the gas pressure equalizing zone 15 with the outside, and a gas introduction pipe 17 is connected to the gas introduction hole 16. Furthermore, the gas supply body 12 includes a porous refractory material 14.
and the passage hole 13, a plurality of relatively large small holes 18 having a diameter of 0.4 to 1.0 mm, and 0.1 to 0.
．． A plurality of relatively small holes 19 with a diameter of 4 am
, . . . are provided alternately in four stages.

According to the molten metal discharging device 5, gas can be supplied at a flow rate of 100 to 1501/win from the relatively large small holes 18, . , the initial opening of the passage hole can be facilitated. Also, during casting, relatively small holes 19,
It is possible to supply an appropriate amount of gas at a flow rate of 5 to 151/win from . Furthermore, after the initial opening, if the gas supply amount is reduced, the relatively large small hole 19. ... Molten steel enters inside, but small holes 19,
Since the porous refractory 14 is provided on the gas equalization zone 15 side, molten metal will not leak to the outside.

In addition, in the above embodiment, the small holes 18, . . . , 19, .
The small holes 18,..., 19,...
The arrangement on the inner surface of the passage hole may be as shown in FIG. 3(a) or (b), for example.

In addition, in the second embodiment, small holes 18, . . .
..., 19, ... were used, but as shown in Figure 4, 0
．． A relatively large slit 20, . . . having a width of 0.1 to 0.4 mm and a relatively small slit 21, . . . having a width of 0.1 to 0.4 mm may be closed.

Furthermore, in the above embodiment, the small holes 18, . . . , 19, .
The porous refractory 14 was provided on the entire surface of the gas pressure equalizing zone 15 side, but as shown in FIG. Even if , . . . are provided, the same effects as in the above embodiment can be obtained.

[Effects of the Invention] As detailed above, according to the molten metal discharge device of the present invention,
It facilitates the initial opening of the passage hole for molten metal, reliably prevents solidification of the molten metal and adhesion of non-metallic inclusions within the passage hole during casting, and prevents leakage accidents of molten metal during casting, making it safe. It has remarkable effects such as improving sexual performance.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing how the molten metal discharge device is used in the embodiment of the present invention, FIG. 2 is a cross-sectional view of the upper fixed plate constituting the molten metal discharge device in the embodiment of the present invention, and FIG. a) and (b) are side views showing the arrangement of small holes in the upper fixed plate constituting the molten metal discharge device in other embodiments of the present invention, and FIGS. 4 and 5 are respectively It is a sectional view of the upper stationary plate which constitutes the molten metal discharge device in still another example of the present invention. 1... Upper nozzle, 2 Upper fixed plate, 3... Slide plate, 4... Lower fixed plate, 5... Molten metal discharge device (sliding nozzle), 6... Immersion nozzle, 7...・Mold, 8... Molten steel, 11... Upper fixed plate body, 12
...Gas supply body, 13... Passing hole, 14.22...
- Porous refractory, 15... Gas equalization zone, 16... Gas introduction hole, 17... Gas introduction pipe, 18.19... Small hole, 2o, 21... Slit. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2

Claims (2)

[Claims] (1) A molten metal discharge device having a fixed plate attached to a nozzle at the bottom of a container containing molten metal, and a sliding plate that opens and closes a passage hole for molten metal by sliding with respect to the fixed plate, The fixed plate is formed of a dense refractory, and the fixed plate is provided with a plurality of gas supply holes having two or more different sizes for supplying gas into the molten metal passage holes, and at least relatively A molten metal discharge device characterized in that a porous refractory is provided on the gas supply side of a large gas supply hole. (2) A relatively large gas supply hole is a small hole with a diameter of 0.4 to 1.0 mm or a slit with a width of 0.4 to 1.0 mm, and a relatively small gas supply hole is a small hole with a diameter of 0.4 to 1.0 mm. 4m
The molten metal discharge device according to claim 1, wherein the molten metal discharge device is a small hole having a diameter of m or a slit having a width of 0.1 to 0.4 mm.