JP3140175B2 - Gas supply device for ladle bottom blow plug - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for supplying gas to a ladle bottom blow plug used in ladle refining or casting of molten steel.

[0002]

2. Description of the Related Art In recent years, as the quality of molten steel for steel has become stricter, there has been an increasing demand for purification at the molten steel stage. In order to purify molten steel, a secondary ladle refining technique for molten steel that has been refined in a steelmaking furnace such as a converter or an electric furnace is essential, so that the molten steel in the ladle is homogenized or nonmetallic inclusions float. The technique of bottom-blown stirring gas for the purpose of separation is widely and generally employed.

For example, Japanese Patent Publication No. 60-56577 discloses a vacuum ladle degassing apparatus for installing a ladle with a porous plug in a vacuum vessel and degassing and refining molten steel in the ladle. Attach a bracket to one of the end of the gas supply pipe connected to the porous plug and fixed to the ladle and the end of the gas introduction pipe fixed to the vacuum vessel, and attach the bracket to the other end. There is disclosed a gas supply connector of a vacuum ladle degassing apparatus in which a cylinder is mounted and an elastic means is interposed in one or both of the bracket and the cylinder to elastically join the bracket and the cylinder.

In the prior art disclosed in the above publication, when degassing and refining molten steel in a ladle installed in a vacuum vessel, gas is blown from a bottom blow plug to stir the molten steel. This is a process, and there is only one gas supply pipe system for supplying gas to the ladle bottom blow plug. For this reason, there was only one connection between the gas supply pipe and the gas introduction pipe connected to one bottom blow plug provided on the ladle and fixed to the ladle.

[0005] As described above, in the conventional ladle refining and casting, the stirring process of molten steel by blowing gas from the ladle bottom blow plug is only one station, so two different connections are made to one bottom blow plug. Did not need to have a department.

[0006]

By the way, as the demand for cleaning at the molten steel stage increases with the stricting of the quality of molten steel for steel, stirring of molten steel by blowing gas from a bottom blow plug provided in a ladle is performed. There is a need to perform processing not only in one station but also in two stations.

[0007] For example, a ladle containing molten steel is placed in a vacuum-sealed container, and while vacuum degassing is performed, gas is bubbled from a bottom blow plug to clean the molten steel. Next, there is a need to inject gas into a tundish while processing molten steel by gas bubbling from a bottom blow plug of the ladle on a ladle holding turner for continuous casting. However, in the case of a porous plug commonly used as a bottom blow plug for a ladle, the gas is stopped once with molten steel in the ladle, and when the back pressure of the plug inside the piping is removed, the molten steel will be in the hole of the porous plug. The plugs are liable to be clogged.

When the molten steel in the ladle is once discharged to stop the gas without cleaning the porous plug and the molten steel is to be treated in the two stations, when the porous plug is reopened, the gas flows due to plug clogging. Not many cases. For this reason, although there is a need to perform bubbling processing by two stations using a ladle bottom blow plug, processing at one station has been forced.

The present invention has been made in view of the above circumstances, and performs external refining of molten steel by blowing gas from a bottom blow plug of a ladle in two different stations. An object of the present invention is to provide a gas supply device to a ladle bottom blow plug that can perform stable bubbling treatment of molten steel without causing clogging.

[0010]

As described above, the necessity of performing gas bubbling from a bottom blow plug of a ladle for performing external refining of molten steel at a plurality of stations has increased. In particular, when gas is bubbled from the bottom-blown plug in a vacuum-sealed vessel for vacuum refining, and when gas is bubbled from the bottom-blown plug to molten steel in the ladle under atmospheric pressure on a ladle holding turner for continuous casting. Therefore, it is often difficult to make the mechanism and the position of the connecting portion between the gas supply pipe fixed to the ladle and the gas introduction pipe not fixed to the ladle uniform. For this reason, it has become necessary to branch the gas supply pipe fixed to the ladle into a plurality of systems from the middle, and to provide a plurality of connecting portions.

That is, the connection between the gas supply pipe fixed to the ladle and the gas introduction pipe not fixed to the ladle, which is connected to the bottom blow plug installed in the vacuum sealed container, is movable by hydraulic pressure or the like. It is difficult to provide a mechanism from the viewpoint of sealing properties and heat measures. For this reason, it is desirable to use a connector that can be automatically attached and detached by a vertical pressing mechanism using the weight of the ladle.

On the other hand, a mechanism for moving the connecting portion in the atmosphere in the horizontal direction by driving a cylinder by hydraulic pressure or the like to attach and detach the connecting portion is often preferable in terms of installation of equipment and maintenance. In addition, when bubbling from the ladle bottom blow plug is performed multiple times at multiple stations, it is necessary to stably suppress clogging of the bottom blow plug when gas supply from the gas supply pipe is interrupted. Become.

According to the present invention, gas bubbling from a bottom blow plug of a ladle can be freely performed at a plurality of stations under vacuum and atmospheric pressure. The results of various studies on a gas supply device for a ladle bottom blown plug that can prevent clogging have been obtained, and the gist thereof is as follows.

According to the present invention , in a gas supply device attached to a ladle provided with a bottom blow plug, a gas supply pipe connected to the bottom blow plug and fixed to the ladle is branched into a plurality of systems on the way. At least one check valve is disposed on each of the plurality of branch pipes, and one end of each of the branch pipes has a substantially vertical connection end.
And the other side is arranged as a connection end in a substantially horizontal direction at a position suitable for connection with a corresponding gas introduction pipe. It is a gas supply device.

The present invention also provides a ladle having a bottom-blown plug.
In the gas supply device attached to the
Connect the gas supply pipe connected to the lag and fixed to the ladle
Branch into multiple systems, and place them on the branch piping of these multiple systems.
With disposing the one check valve at least, respectively, the one side of the connection end of each branch pipe is connected end to be used in a vacuum sealed container, the other side is connected to be used in the atmosphere End and
Position suitable for connection with the corresponding gas introduction pipe
A gas supply device to be that collected by the pan bottom blown plug wherein Rukoto such be placed.

Further, the present invention provides a housing provided with a bottom blow plug.
In the gas supply device attached to the pan,
Connect the gas supply pipe connected to the plug and fixed to the ladle
Branch into multiple systems, and
Respectively at least with disposing the one check valve, one side of the connecting end portion of the respective branch pipes are connected end in the substantially vertical direction for use in a vacuum sealed container, the other The side is used as a connection end in a substantially horizontal direction for use in the atmosphere.
Arrange them at suitable positions for connection with the corresponding gas introduction pipes.
Rukoto such Te is a gas supply device to be that collected by the pan bottom blown plug characterized.

[0017]

In order to provide different connection ends to the gas supply pipe fixed to the ladle and connected to the bottom blow plug provided on the ladle, the gas supply pipe is branched into a plurality of systems on the way. Since the positions of the connection end portions of these multiple branch pipes are arranged at positions suitable for connection with the corresponding gas introduction pipes, the molten steel in the ladle at multiple stations with different gas supply mechanisms and positions is provided. Bubbling can be performed with good workability without trouble such as gas leakage.

Further, since at least one check valve is provided on each branch pipe of the plurality of systems, when the gas supply from the gas introduction pipe is interrupted, the check valve prevents the gas from flowing backward.
The back pressure of the blow plug is maintained. As a result, since the molten steel in the ladle can be prevented from entering the blow plug, plug clogging is eliminated and gas blowing can be reliably restarted. This enables bubbling of molten steel in the ladle at multiple stations.

Preferably, one of the connection ends of the plurality of branch pipes is a connection end in a substantially vertical direction, and the other side is a connection end in a substantially horizontal direction. When bubbling the inner molten steel in a vacuum sealed container, or when bubbling in the atmosphere,
Molten steel bubbling processing at a plurality of stations can be easily performed.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a bottom blow plug 2 provided at the bottom of a ladle 1.
The gas supply pipe 3 connected to the ladle 1 and fixed to the ladle 1 is branched into two systems on the way, and two check valves 4 are respectively arranged in series on these two system branch pipes 3a and 3b. is there. Of the branch pipes 3a and 3b, the connection end 5 of one of the branch pipes 3a is fixedly arranged at a position near the lower portion of the outer wall of the ladle 1,
The connection end 7 of the other branch pipe 3b is fixedly arranged at a position near the upper part of the outer wall of the ladle 1.

The connection end 5 of the branch pipe 3a is connected to the vertical connection end 6 of the gas introduction pipe 17a by moving in the vertical direction, and the connection end of the branch pipe 3b is The connection is made by moving the horizontal connection end 8 connected to the introduction pipe 17b (in this case, a hose) in the horizontal direction. That is, when the connection end portion 5 on the branch pipe 3a side fixed to the ladle 1 and the connection end portion 6 on the gas introduction pipe 17a side are attached and detached, the connection end portion 5 is raised and lowered by moving the ladle 1 vertically. It is performed by moving. Needless to say, gas leaks are sealed when joined by connecting a heat-resistant packing (not shown) between the connection ends 5 and 6.

When the connection end 7 of the branch pipe 3b fixed to the ladle 1 is connected to or detached from the connection end 8 of the gas introduction pipe 17b by connecting or detaching, the connection end 8 is connected to the horizontal drive shaft. 9 by a drive cylinder 13 to approach or separate in the horizontal direction. It is the same to secure the seal by interposing a seal packing (not shown) between the connection ends 7 and 9.

FIG. 2 shows that the ladle 1 containing the molten steel 10 is placed in a vacuum sealed container 11 composed of a closed container body 11a and a lid 11b, and is evacuated by a vacuum pump (not shown) through an exhaust duct 11c. A case is shown in which gas is degassed under vacuum and gas bubbling is performed. For vacuum degassing, first cover 11
b, the ladle 1 containing the molten steel 10 is suspended by a crane (not shown) in the closed vessel main body 11a, and the supporting shaft 19 provided on the outer wall of the ladle 1 is set on the set table 18 in the closed vessel main body 11a.
Is set on the ladle 1, and the branch pipe 3a is fixed to the ladle 1.
As the connection end portion 5, joined by moderate pressing force in the vertical direction from the upper to the connection end 6 through a heat seal (not shown) of a fixed to the closed container body 11 a gas introduction pipe 17a The connection is made without gas leakage.

While the molten steel 10 in the ladle 1 is degassed in the vacuum sealed container 11, Ar gas is supplied from the gas supply pipe 3, and the molten steel 10 is stirred by gas bubbling from the bottom blow plug 2. Degassing of molten steel 10 is promoted. During the degassing process, the inside of the vacuum sealed container 11 becomes hot, but the connection ends 5, 6
Is made of steel, and only heat-resistant packing for sealing is interposed between the two, so that Ar gas can be supplied in a stable state.

When the vacuum degassing process is completed, the gas introduction pipe 17
interrupting the supply of the Ar gas from a can, the back pressure of the bottom blowing plug 2 because back flow of gas is prevented by the check valve 4 arranged in two not a One series respectively to the branch pipes 3a and 3b is held Thus, intrusion of molten steel 10 into plug 2 is prevented.
After removing the lid 11b After returning the vacuum enclosure 11 to the atmospheric pressure, that the ladle 1 the sealed container body 11 in a readily detached from the lifting vertically by a crane connection end 5 and 6 it can.

FIG. 3 shows that a ladle 1 containing molten steel subjected to vacuum degassing is placed on a tundish of a continuous casting apparatus, and then poured into a tundish 14 while gas bubbling from a bottom blow plug 2. In this case, a slab 16 is cast by casting the slab. In the continuous casting, first, a support shaft 19 provided on the outer wall of the ladle 1 is placed on a ladle support device 12 provided on a ladle holding turner (not shown) and supported. The connection end 8 is fixed to the ladle 1 and is located near the upper part of the outer wall. The connection end 8 is operated under the atmospheric pressure by the drive cylinder 13 to be advanced in the horizontal direction via the horizontal drive shaft and securely joined. Let it. Since a sealing packing is interposed between the connection ends 7 and 8, the connection can be made airtight.

When the connection between the connection ends 7 and 8 is completed, Ar gas introduced from the gas introduction pipe 17b is supplied to the bottom blow plug 2 through the branch pipe 3b, and the molten steel in the ladle 1 is supplied.
As described above, the slab 16 is manufactured by bubbling 10 and injecting it into the tundish 14 while floating the inclusions, and then casting the tundish 14 into the mold 15. When the injection of molten steel in ladle 1 is completed, Ar from gas introduction pipe 17b
The Although stops the supply of the gas backflow of gas is prevented by the check valve 4 arranged in series One not a two respective branch pipes 3a and 3b are the same as described above. afterwards,
The drive cylinder 13 is driven to retract the connection end 8 to be separated from the connection end 7, and the ladle 1 is lifted by a crane and carried out.

Table 1 shows a case where one check valve is used for each of two gas supply pipes to the bottom blow plug according to the apparatus of the present invention, an example of the present invention where two check valves are used, and one system. The situation of the 2nd and 3rd time bubbling success rate from the bottom blow plug in the conventional example which does not use a check valve in a gas supply pipe is shown.

[0029]

[Table 1]

As shown in Table 1, the bubbling success rate of the example of the present invention using the check valve is higher than that of the conventional example not using the check valve, particularly when two check valves are used in series. It can be seen that the success rate of has significantly improved. This is nothing less than the effectiveness of multiple uses of the check valve.

[0031]

As described above, according to the present invention, the gas to the bottom-blowing bubbling plug of the ladle is supplied from a plurality of different connection ends arranged at positions suitable for connection with the gas introduction pipe. Further, since the check valve can suppress the infiltration of molten steel into the bottom blow plug when the gas supply is interrupted, molten steel bubbling can be performed at a plurality of stations having different gas supply mechanisms and positions.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an apparatus of the present invention.

FIG. 2 is a schematic explanatory view when the device of the present invention is used in a vacuum.

FIG. 3 is a schematic explanatory view when the device of the present invention is used in the atmosphere.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Ladle 2 Bottom blow plug 3 Gas supply pipe 3a Branch pipe 3b Branch pipe 4 Check valve 5 Vertical connection end on branch pipe side 6 Vertical connection end on gas introduction pipe side 7 Horizontal connection on branch pipe side End 8 Horizontal connection end on gas introduction pipe side 9 Horizontal drive shaft 10 Molten steel 11 Vacuum sealed container 11a Sealed container body 11b Cover 11c Exhaust duct 12 Ladle support device 13 Drive cylinder 14 Tundish 15 Mold 16 Cast piece 17 Gas inlet pipe 18 Set table 19 Support shaft

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B22D 1/00 C21C 7/072 C21C 7/10

Claims (3)

(57) [Claims] 1. A gas supply device attached to a ladle having a bottom blow plug, wherein a gas supply pipe connected to the bottom blow plug and fixed to the ladle is branched into a plurality of systems on the way, At least one check valve is disposed on each of the branch pipes of the plurality of systems, and one end of the connection end of each branch pipe is a connection end in a substantially vertical direction,
A gas supply device for a ladle bottom blow plug, wherein the other side is disposed as a connection end in a substantially horizontal direction at a position suitable for connection with a corresponding gas introduction pipe. 2. A ladder provided with a bottom-blowing plug.
Connected to the bottom blow plug
And the gas supply pipe fixed to the ladle is divided into multiple
At least on each of these multiple branch pipes.
With disposing the one check valve, said one side of the connection end of each branch pipe is connected end to be used in a vacuum sealed container, the other side is provided as connecting end for use in air
Corresponding gas inlet tube and a gas supply device to the pan bottom blown plug preparative you characterized Do <br/> isosamples placed in a suitable position in connection. 3. A ladle provided with a bottom-blowing plug and attached to a ladle.
Connected to the bottom blow plug
And the gas supply pipe fixed to the ladle is divided into multiple
At least on each of these multiple branch pipes.
One check valve is provided, and one end of the connection end of each branch pipe is substantially vertically used in a vacuum sealed container.
A connection end in the direction, the other side is real for use in air
Quasi-qualitatively as the connection ends in the horizontal direction,
Scan inlet pipe and the gas supply device to be that collected by the pan bottom blown plug wherein an disposed in a suitable position Rukoto connection.