JP3723403B2 - Method and apparatus for sealing molten metal flow - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for sealing an injected molten metal flow when injecting molten metal from an injection nozzle arranged at the bottom of a container containing molten metal into a container for receiving molten metal arranged below the injection nozzle, and It relates to the device.
[0002]
[Prior art]
Conventionally, when molten metal is injected from a container to a container (for example, a ladle to a ladle, a ladle to a tundish, etc.) via an injection nozzle, the molten metal comes into contact with the outside air, and the molten metal is oxidized at that time. Incorporation of components such as moisture and nitrogen in the atmosphere may cause fluctuations in the molten metal component, making it impossible to produce a molten metal having a predetermined metal component.
[0003]
As methods for improving the above problems, there are methods proposed in, for example, Japanese Patent Laid-Open Nos. 63-235053 and 62-81253.
[0004]
In Japanese Patent Laid-Open No. 63-235053, in order to suppress the oxidation of the molten metal injected from the ladle into the tundish, the molten metal injected into the tundish through the molten metal injection nozzle is injected into the tundish. In the method, the cylindrical member is immersed in a region including the molten metal injection portion of the molten metal surface in the tundish, and a gas that does not react with the molten metal is supplied to a region surrounded by the cylindrical member at the upper surface of the molten metal, and this gas There has been proposed a molten metal injection method in which a molten metal outflow portion of the molten metal injection nozzle is positioned in a supply region to inject molten metal in a ladle.
[0005]
Further, Japanese Patent Laid-Open No. 62-81253 discloses that the ladles are poured into the tundish in order to more effectively prevent the sorption of nitrogen from the ambient atmosphere of the molten steel poured into the tundish. A sealing method for preventing nitrogen absorption from the ambient atmosphere of molten steel, in which a molten steel flow injected from the nozzle tip at the bottom of the ladle is partitioned from the external atmosphere, and an inert gas is present in the molten steel flow near the surface of the molten steel in the tundish There has been proposed a method of sealing the molten molten steel flow.
[0006]
[Problems to be solved by the invention]
However, in the specific example proposed in Japanese Patent Laid-Open No. 63-235053, the upper end of the cylindrical member is opened, and a gas supply pipe is inserted into the cylindrical member from the upper end, and an argon gas which is an inert gas from the distal end. Is blown toward the molten metal surface. For this reason, there is a concern about air contamination from the upper end opening, and there is a concern that oxidation of the molten metal is not necessarily performed because the air is not sufficiently blocked. On the other hand, even if the upper end opening is closed, the upper part in the cylindrical member becomes negative pressure due to the gas entrained in the molten metal injected into the tundish in order to keep the molten metal level constant, and from the gap etc. There is concern about the oxidation of the molten metal. Thus, the proposed sealing method cannot reliably produce a molten metal having a desired cleanliness.
[0007]
In the method proposed in Japanese Patent Laid-Open No. 62-81253, as shown in FIG. 4, a molten steel flow 23 injected from the nozzle tip 22 of the ladle bottom 21 is divided into a lid (Jinkasa) 24, a seal hat (intermediate). (Cylinder) 25, an injection pipe (seal pipe) 26, and an inert gas guide pipe 27, which is partitioned from the external atmosphere by a sealing device 28, and in the vicinity of the surface of the molten steel in the tundish in the partition, An active gas is sprayed. However, in this method, the upper part in the sealing device 28 becomes a negative pressure due to the bubbles 29 of the inert gas entrained in the molten metal injected into the tundish in order to keep the molten metal level constant. As shown in FIG. 4 together, there is an intrusion of the atmosphere from the joint gap between the portion (Jinkasa) 24, the seal hat (intermediate cylinder) 25, and the injection pipe (seal pipe) 26, as indicated by the broken arrow B. There is concern about the oxidation of Thus, even with this proposed sealing method, it is impossible to reliably produce a molten metal having a desired cleanliness. Reference numeral 30 denotes an inert gas outlet.
[0008]
On the other hand, in Japanese Patent Laid-Open No. 6-344098, as a method for solving the problem of the above-mentioned Japanese Patent Laid-Open No. 62-81253, an inert gas is injected from an inert gas blowing port installed on the outer periphery of the lower nozzle. There has been proposed a method of sealing an injected molten steel flow in which the blown inert gas is blown as a swirling flow and spirally wound around the injected molten steel flow.
[0009]
However, in the method proposed in Japanese Patent Laid-Open No. 6-344098, the inert gas that has been blown is spirally wound around the molten molten steel flow, and although the cleanliness of the molten molten steel flow from the nozzle can be expected, the inert gas In this method, the upper part of the sealing device is blocked by bubbles of inert gas entrained in the molten metal injected into the tundish in order to keep the molten metal surface constant. There is concern about oxidation of the molten metal due to the negative pressure and the intrusion of air through gaps.
[0010]
The present invention has been made to solve the above-mentioned problems, and its purpose is to prevent the intrusion of air into the sealing device as much as possible, and to manufacture a molten metal having a desired cleanliness assuredly. The present invention provides a method and an apparatus for sealing an obtained molten metal flow.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a method for sealing a molten metal flow according to the present invention receives molten metal disposed below an injection nozzle from an injection nozzle disposed at the bottom of a container containing molten metal. A method for sealing a molten metal flow when pouring molten metal into a container, wherein a lid is attached to the outer periphery of the injection nozzle, and a cylindrical member is provided on the lid so as to surround the outer periphery of the molten melt flow At the same time, an inert gas outlet is provided in a ring shape on the upper side wall of the cylindrical member, and the inert gas from the inert gas outlet is ejected toward the lid ceiling in the cylindrical member.
[0012]
In said structure, while providing a cylindrical member so that the outer periphery of an injection | melting molten metal flow may be bent, an inert gas jet nozzle is provided in the ring shape at the upper side wall of the cylindrical member, and it is from the inert gas jet nozzle. Since the inert gas is jetted toward the lid ceiling in the cylindrical member, a part of the inert gas flow that collided with the lid ceiling flows along the inner surface of the cylindrical member, thereby the cylindrical member. Intrusion of air into the interior can be prevented, and a molten metal having a desired cleanliness can be produced reliably.
[0013]
The injection molten metal flow sealing device according to the present invention injects molten metal from an injection nozzle arranged at the bottom of a container containing molten metal into a container for receiving molten metal arranged below the injection nozzle. An injection molten metal flow sealing device for performing an injection, comprising: a lid portion attached to the injection nozzle; a seal pipe provided in a hot water receiving opening of a hot water receiving container; provided on the seal pipe and inactive A ring-shaped inert gas ejection portion having a gas ejection port facing upward, and an intermediate cylinder provided between the lid portion and the inert gas ejection portion. In this case, the ring-shaped inert gas ejection portion may be formed as an integral ring. However, in consideration of ease of production, a plurality of linear or arc-shaped nozzles are configured in a ring shape. It may be.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view of an injection melt flow sealing device according to the present invention, in which a is an overall sectional view and b is an enlarged sectional view of an inert gas ejection portion.
[0015]
The sealing device 1 is provided between the bottom of the pouring vessel (ladder) 2 and the hot water receiving vessel (tundish) 3 so as to surround the pouring flow 5 from the injection nozzle 4. The structure of the apparatus 1 is provided in close contact with the lid 6 attached to the injection nozzle 4, the seal pipe 8 provided in the hot water receiving opening 7 of the hot water receiving container 3, and the seal pipe 8. A ring-shaped inert gas ejection portion 10 having an inert gas ejection port 9 facing upward, and an intermediate cylinder 11 provided between the lid portion 6 and the inert gas ejection portion 10. It is prepared for.
[0016]
In the sealing device 1 configured as described above, the inert gas ejection port 9 of the inert gas ejection part 10 is formed upward, so that the inert gas ejected from the inert gas ejection port 9 is formed. flow (indicated by arrow a in FIG. 1), the lid portion 6 collides with the ceiling first, then, part flows along the intermediate tubular member 11 the inner surface of the lid portion 6 ceiling, others from central lid portion 6 ceiling Flow toward the injection nozzle 4. Further, when the molten metal in the pouring vessel 2 is poured into the hot water receiving vessel 3 through the pouring nozzle 4, the other flow is along the outer periphery of the pouring nozzle 4 and the pouring flow 5. Will flow.
[0017]
In the seal device 1 of the injection melt flow, the inert gas from the inert gas nozzle 10 is ejected toward the upper collide with the lid portion 6 ceiling, lid part of the inert gas stream A 6 Since it flows along the inner surface of the intermediate cylinder 11 from the ceiling, the vicinity of the inner side of the intermediate cylinder 11 is unlikely to become negative pressure, thereby preventing air from entering the seal device 1 and ensuring that it is desired. It is possible to produce a molten metal having a cleanliness of
[0018]
【Example】
[Example 1]
The above injection molten metal flow sealing device 1 was installed between a ladle and a tundish to perform continuous casting of molten low carbon steel. For comparison, an inert gas blowing pipe was provided instead of the inert gas jetting part 10 and the jet outlet was directed toward the molten steel surface of the tundish, and the same low carbon steel molten steel was continuously cast. In this casting, argon gas was used as an inert gas, the nitrogen gas concentration in the vicinity of the molten steel surface in the seal pipe 8 was measured, and the sealing properties of the method of the present invention and the comparative method were investigated. The survey results are shown in FIG. As is clear from FIG. 2, the method for sealing the molten metal flow according to the present invention has a nitrogen gas concentration in the vicinity of the molten steel surface in the seal pipe 8 at any inert gas flow rate as compared with the comparative method. It can be significantly reduced and is found to be useful for preventing air intrusion.
[0019]
In addition, during the above-described continuous casting, each of the [N] concentration in the molten steel in the pouring vessel and the [N] concentration in the molten steel in the receiving vessel at the end of casting were measured. The measurement results are shown in FIG. As is clear from FIG. 3, the molten metal flow sealing method according to the present invention is more molten steel at the time of receiving hot water than [N] concentration in the molten steel in any pouring vessel compared to the comparative method. It can be seen that there is no increase in the medium [N] concentration, which is useful for preventing air intrusion and is excellent as a method for cleaning molten steel.
[0020]
【The invention's effect】
As described above, according to the injection molten metal flow sealing method and apparatus according to the present invention, the intrusion of air into the sealing apparatus can be prevented, and a molten metal having a desired cleanliness can be manufactured reliably. .
[Brief description of the drawings]
FIG. 1 is an explanatory view of an injection molten metal flow sealing device according to the present invention, in which a is an overall cross-sectional view and b is an enlarged cross-sectional view of an inert gas ejection portion.
FIG. 2 is a graph showing the relationship between the nitrogen gas concentration inside the seal pipe and the inert gas flow rate in the example.
FIG. 3 is a graph showing the relationship between the [N] concentration in the molten steel in the pouring vessel and the [N] concentration in the molten steel in the receiving vessel in the example.
FIG. 4 is a cross-sectional view of a conventional sealing device for molten metal flow.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1: Sealing device 2: Pouring container 3: Hot water receiving container 4: Injection nozzle 5: Pouring flow 6: Lid part 7: Hot water opening 8: Seal pipe 9: Inert gas outlet 10: Inert gas ejection part 11: Intermediate cylinder A: Inert gas flow

Claims (3)

A method for sealing an injected molten metal flow when injecting molten metal from an injection nozzle disposed at the bottom of a container containing molten metal into a container for receiving molten metal disposed below the injection nozzle, A lid is attached to the outer periphery of the injection nozzle, and a cylindrical member is provided on the lid so as to surround the outer periphery of the molten metal flow, and an inert gas outlet is provided in a ring shape on the upper side wall of the cylindrical member. A method for sealing an injected molten metal flow, characterized in that an inert gas from the inert gas outlet is ejected toward the ceiling of the lid in the cylindrical member. An injection molten metal flow sealing device for injecting molten metal from an injection nozzle disposed at the bottom of a container containing molten metal into a container for receiving molten metal disposed below the injection nozzle, Ring-shaped inert gas provided with a lid attached to the injection nozzle, a seal pipe provided in the hot water receiving opening of the hot water receiving container, and provided on the seal pipe with an inert gas outlet facing upward An injection molten metal flow sealing device comprising: a gas ejection portion; and an intermediate cylinder provided between the lid portion and the inert gas ejection portion.   The apparatus for sealing an injected molten metal flow according to claim 2, wherein the ring-shaped inert gas ejection portion is constituted by a plurality of linear or arc-shaped nozzles.

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