JP2001259804A - Sealing method for poured molten metal stream and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device for poured molten metal stream in which the invasion of the air into the sealing device is prevented as much as possible and the molten metal having desired cleanliness can surely be produced. SOLUTION: In the sealing device 1 for poured molten metal stream when the molten metal poured into a vessel 3 for receiving the molten metal disposed at the lower part of a pouring nozzle 4 from the pouring nozzle 4 disposed at the bottom part of the vessel 2 for holding the molten metal, this sealing device 1 is provided with a helmet part 6 fitted to the pouring nozzle 4, a seal pipe 8 arranged at the opening part 7 for receiving the molten metal in the vessel 3 for receiving the molten metal, an annular inert gas spouting part 10 arranged on the seal pipe 8 and having an inert gas spouting hole 9 toward the upper part and an intermediate cylindrical body 11 arranged between the helmet part 6 and the inert gas spouting part 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for pouring molten metal from a pouring nozzle disposed at the bottom of a container for accommodating molten metal into a container for receiving molten metal disposed below the pouring nozzle. The present invention relates to a method and an apparatus for sealing a flow of a molten metal.

[0002]

2. Description of the Related Art Conventionally, when molten metal is injected from a container to a container (eg, a ladle to a ladle, a ladle to a tundish, etc.) through an injection nozzle, the molten metal comes into contact with the outside air. Oxidation of the molten metal and incorporation of components such as moisture and nitrogen in the atmosphere may cause variation in the molten metal component, making it impossible to produce a molten metal of a predetermined metal component.

As a method for solving the above problems, for example, Japanese Patent Application Laid-Open Nos. 63-235053 and
There is a method proposed in Japanese Patent Publication No. 2-81253.

Japanese Patent Application Laid-Open No. 63-235053 discloses that a molten metal in a ladle is injected into a tundish through a molten metal injection nozzle in order to suppress oxidation of the molten metal injected from the ladle into the tundish. In the method for injecting a molten metal, a cylindrical member is immersed in a region including a molten metal injection portion of a molten metal surface in a tundish, and a gas that does not react with the molten metal is supplied to a region surrounded by the cylindrical member on the upper surface of the molten metal. There has been proposed a method for injecting a molten metal in which a molten metal outflow portion of the molten metal injection nozzle is positioned in the gas supply region and the molten metal in the ladle is injected.

Japanese Patent Application Laid-Open No. 62-81253 discloses that a ladle is changed from a ladle to a tundish in order to more effectively prevent nitriding of molten steel injected from a ladle (ladle) into the tundish from the surrounding atmosphere. A sealing method for preventing nitrogen absorption from the surrounding atmosphere of molten steel to be injected, wherein the molten steel flow injected from the nozzle tip at the bottom of the ladle is partitioned from an external atmosphere, and the molten steel flow is formed near the surface of molten steel in a tundish. A method of sealing an injected molten steel stream by blowing an inert gas has been proposed.

[0006]

However, in a specific example proposed in Japanese Patent Application 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. Argon gas, which is an inert gas, is blown from the tip toward the molten metal surface. For this reason,
There is a concern that the air may be mixed in from the upper end opening, and that the air may not always be sufficiently shut off and the molten metal may be oxidized. On the other hand, even if the upper end opening is closed, the upper part in the cylindrical member becomes a negative pressure due to the gas entangled in the molten metal injected into the tundish in order to maintain the level of the molten metal at a constant level. There is a risk of oxidation of the molten metal due to the intrusion of the atmosphere. Thus, the proposed sealing method cannot reliably produce a molten metal having a desired cleanliness.

In the method proposed in Japanese Patent Application Laid-Open No. 62-81253, as shown in FIG. 4, a molten steel flow 23 injected from a nozzle tip 22 of a ladle bottom 21 is covered by a lid (a kinkasa) 24 and a seal. A seal device 28 composed of a hat (intermediate cylinder) 25, an injection pipe (seal pipe) 26, and an inert gas guide pipe 27 separates from the external atmosphere, and the molten steel flows near the surface of the molten steel in the tundish in that section. 23 is blown with an inert gas. However, in this method, the upper portion of the sealing device 28 becomes negative pressure due to the bubble 29 of the inert gas which is caught in the molten metal injected into the tundish in order to maintain the level of the molten metal. As shown in FIG. 4, the atmosphere enters as shown in FIG. Oxidation is a concern. Thus, even with this proposed sealing method, a molten metal having a desired cleanliness cannot be reliably produced. In addition, 3
0 is an inert gas ejection port.

On the other hand, Japanese Patent Application Laid-Open No. 6-344098 discloses a method for solving the problem of Japanese Patent Application Laid-Open No. 62-81253, in which an inert gas is injected from an inert gas injection port installed on the outer periphery of a lower nozzle. There has been proposed a method for sealing an injected molten steel flow, in which the injected molten steel flow is blown in as a swirling flow, and the injected inert gas is spirally wound around the injected molten steel flow.

However, Japanese Patent Application Laid-Open No. 6-34409 describes
According to the method proposed in Japanese Patent Publication No. 8 (1996), the cleanness of the injected molten steel flow from the nozzle can be expected in that the injected inert gas is spirally wound around the injected molten steel flow, but the injection of the inert gas is directed downward. In this method, even in this method, the upper part of the sealing device becomes negative pressure due to the inert gas bubbles caught in the molten metal injected into the tundish in order to maintain the level of the molten metal, and the gaps and the like are reduced. There is concern about oxidation of the molten metal due to intrusion of air from the atmosphere.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to prevent the intrusion of the atmosphere into a sealing device as much as possible and to ensure that a molten metal having a desired cleanliness is obtained. It is intended to provide a method and an apparatus for sealing a flow of an infused molten metal, which can produce the same.

[0011]

In order to achieve the above-mentioned object, a method for sealing a molten metal flow according to the present invention is described in which a method for sealing a molten metal flow from an injection nozzle disposed at the bottom of a container containing molten metal to a position below the injection nozzle. What is claimed is: 1. A method for sealing a molten metal flow when a molten metal is poured into a container for receiving a placed molten metal, comprising: A cylindrical member is provided so as to be bent, and an inert gas ejection port is provided in a ring shape on an upper side wall of the cylindrical member, and inert gas from the inert gas ejection port is supplied to a ceiling of a jinkasa portion in the cylindrical member. It is to squirt toward.

In the above configuration, the cylindrical member is provided so as to bend the outer periphery of the flow of the molten metal, and the inert gas injection port is provided in the upper side wall of the cylindrical member in a ring shape. Since the inert gas from the outlet is ejected toward the ceiling of the jinkasa portion in the cylindrical member, a part of the inert gas flow that has collided with the ceiling of the jinkasa portion flows along the inner surface of the cylindrical member. The entry of the atmosphere into the tubular member can be prevented, and a molten metal having a desired cleanliness can be reliably produced.

Further, according to the present invention, there is provided a sealing apparatus for a molten metal flow, wherein the molten metal is melted from an injection nozzle arranged at the bottom of a container for accommodating the molten metal to a container for receiving the molten metal arranged below the injection nozzle. A seal device for a molten metal flow when metal is injected, which is provided on a seal pipe provided at a hot water receiving opening of a hot water receiving container, a seal pipe attached to the injection nozzle, and a seal pipe, In addition, it comprises a ring-shaped inert gas ejection section having an inert gas ejection port facing upward, and an intermediate cylinder provided between the jinkasa section and the inert gas ejection section. In this case, the ring-shaped inert gas ejection portion may be formed as an integral ring, but in consideration of ease of manufacture, a plurality of linear or arc-shaped nozzles are formed in a ring shape. It may be.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view of a sealing device for a molten metal flow 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 part.

The sealing device 1 is provided between the bottom of the pouring vessel (ladle) 2 and the hot water receiving vessel (tandish) 3 so as to surround the pouring flow 5 from the injection nozzle 4.
Further, the structure of the apparatus 1 is such that a cap section 6 attached to the injection nozzle 4, a seal pipe 8 provided in the hot water receiving opening 7 of the hot water receiving container 3, and a seal pipe 8 provided in close contact with the seal pipe 8. A ring-shaped inert gas ejection portion 10 having an inert gas ejection port 9 facing upward, an intermediate cylinder 11 provided between the kinkasa portion 6 and the inert gas ejection portion 10,
It is provided with.

In the sealing device 1 configured as described above, since the inert gas ejection port 9 of the inert gas ejection section 10 is formed upward, the gas is ejected from the inert gas ejection port 9. Inert gas flow (indicated by arrow A in FIG. 1)
Firstly collide with the ceiling of the Jinkasa portion 6, and then a part flows from the ceiling of the Jinkasa portion 6 along the inner surface of the intermediate cylinder 11, and the other flows from the ceiling of the Jinkasa portion 6 toward the injection nozzle 4 in the center. Further, when the molten metal in the pouring vessel 2 is poured into the pouring vessel 3 through the pouring nozzle 4, the other flow flows along the outer periphery of the pouring nozzle 4 and the pouring stream 5. Will flow.

In the above-described sealing device 1 for molten metal flow, the inert gas from the inert gas jetting section 10 is jetted upward and collides with the ceiling of the jinkasa section 6, and a part of the inert gas stream A is removed. Since it is made to flow along the inner surface of the intermediate cylinder 11 from the ceiling of the kinkasa 6, it is difficult for negative pressure to occur near the inside of the intermediate cylinder 11, thereby preventing the intrusion of the atmosphere into the sealing device 1, Molten metal having a desired cleanliness can be reliably produced.

[0018]

[Example 1] The above-described sealing device 1 for molten metal flow was equipped between a ladle and a tundish to continuously cast low carbon steel molten steel. For comparison, the same low carbon steel molten steel was continuously cast by installing an inert gas injection pipe instead of the inert gas injection part 10 with the injection port facing the molten steel surface of the tundish. In this casting, an argon gas was used as an inert gas, and the nitrogen gas concentration near 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. FIG. 2 shows the result of the investigation. FIG.
As is clear from the comparison, the method of sealing the molten metal flow according to the present invention significantly reduces the nitrogen gas concentration near the molten steel surface in the seal pipe 8 at any inert gas flow rate as compared with the comparative method. And is useful in preventing atmospheric intrusion.

In the above continuous casting, 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. FIG. 3 shows the measurement results. As is clear from FIG. 3, the method for sealing the molten metal flow according to the present invention is more effective than the comparative method for the [N] concentration in the molten steel in any of the pouring vessels at the time of receiving molten metal. It can be seen that there is no increase in the concentration of medium [N], which is useful for preventing intrusion into the atmosphere, and is excellent as a method for cleaning molten steel.

[0020]

As described above, according to the method and apparatus for sealing a molten metal flow according to the present invention, it is possible to prevent the intrusion of the atmosphere into the sealing apparatus and to reliably remove molten metal having a desired cleanliness. Can be manufactured.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view of a molten metal 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 part.

FIG. 2 is a graph showing the relationship between the nitrogen gas concentration inside a seal pipe and the flow rate of an inert gas in an example.

FIG. 3 is a graph showing the relationship between the [N] concentration in molten steel in a pouring vessel and the [N] concentration in molten steel in a receiving vessel in an example.

FIG. 4 is a cross-sectional view of a conventional sealing device for molten metal flow.

[Explanation of symbols]

1: Sealing device 2: Pouring container
3: Hot water container 4: Injection nozzle 5: Pouring flow
6: Jinkasa 7: Hot water opening 8: Seal pipe
9: Inert gas spout 10: Inert gas spout 11: Intermediate cylinder
A: Inert gas flow

Claims (3)

[Claims] 1. A method for sealing a molten metal flow when pouring molten metal from a pouring nozzle disposed at the bottom of a container accommodating molten metal to a container receiving molten metal disposed below the pouring nozzle. A jig portion is attached to the outer periphery of the injection nozzle, and a cylindrical member is provided on the girder portion so as to bend the outer periphery of the molten metal flow, and a ring-shaped inactive member is formed on an upper side wall of the cylindrical member. A method for sealing a molten metal flow, comprising: providing a gas outlet, and injecting an inert gas from the inert gas outlet toward a ceiling of a jinkasa portion in a tubular member. 2. A device for sealing a molten metal flow when pouring molten metal from a pouring nozzle arranged at the bottom of a container for accommodating molten metal into a container for receiving molten metal disposed below the pouring nozzle. Wherein a cap section attached to the injection nozzle, a seal pipe provided at a hot water receiving opening of the hot water receiving vessel, and an inert gas ejection port provided on the seal pipe and facing upward. A sealing device for a molten metal flow, comprising: a ring-shaped inert gas jetting portion; and an intermediate cylinder provided between the jinkasa portion and the inert gas jetting portion. 3. The ring-shaped inert gas ejection portion is constituted by a plurality of straight or circular nozzles.
The sealing device for molten metal flow according to claim 1.