JPH0576654U - Tundish equipment for continuous casting - Google Patents

Abstract

(57) [Summary] [Purpose] Molten steels with different compositions are cast while continuing casting. Reduce the component mixing section. Keep the molten steel head constant. [Structure] The inside of the tundish 10 is partitioned by a partition wall 20 into a dipping nozzle side and a molten steel receiving side. A gap 21 is provided below the partition wall 20. The tundish 10 is provided with a lid 30 that hermetically seals the space on the molten steel receiving side except the gap 21. When casting molten steel having different components, the space on the molten steel receiving side is hermetically sealed, and an inert gas is pressed into the space to move the molten steel on the molten steel receiving side to the dipping nozzle side. After sufficiently reducing the molten steel on the molten steel receiving side, the molten steel having different components is supplied to the molten steel receiving side.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a continuous casting tundish device capable of continuously casting molten steel having different components without stopping casting.

[0002]

[Prior Art]

 As is well known, continuous casting allows endless continuous casting by continuously supplying the molten steel into the tundish if the molten steel has the same composition. However, recently, the needs have diversified, and it is rather rare to continuously cast the same molten steel for a long time, and the chances of casting molten steel with different compositions little by little one after another have increased. In that case, the switching of molten steel has been performed by the following methods.

Casting is completed and casting is started again. The tundish is emptied during casting and the casting is suspended. During this time, a jig for connecting the cast pieces and a separation plate for preventing molten steel from mixing are set in the mold, and the casting is restarted. Continuously cast molten steel with different components.

[0004]

[Problems to be solved by the device]

 In this method, the characteristics of continuous casting are destroyed, resulting in a large loss of time. With this method, the quality of continuous casting is maintained for the time being, but some time loss is unavoidable. Moreover, when the tundish is emptied, the molten steel head in the tundish lowers, so it is necessary to fully open the sliding gate. Extreme movement of the sliding gate causes the inclusion of adhering inclusions due to vibration, which causes deterioration of the quality of the slab. This method completely preserves the characteristics of continuous casting. However, a large proportion of the component mixing part occurs, and by scrapping this part later, a large yield loss occurs.

The object of the present invention is to enable the switching of molten steel while continuing casting, to make the component mixing section much smaller than before, and without the risk of quality deterioration due to extreme movement of the sliding gate. An object is to provide a tundish device for continuous casting.

[0006]

[Means for Solving the Problems]

 The tundish device for continuous casting according to the present invention comprises a tundish in which molten steel is supplied from above one end and a submerged nozzle is projected below the other end, and the submerged nozzle side is left inside the mendish leaving a lower end. And a molten steel receiving side, and a lid body that hermetically seals the space on the molten steel receiving side in the tundish leaving the lower part of the partition wall openable and capable of opening and closing the molten steel receiving part, and the molten steel receiving side. And an inert gas pressure acquisition stage connected to the side space.

[0007]

[Action]

 When switching the molten steel, first stop the pouring of the molten steel into the molten steel injection side in the tundish, and close the molten steel receiving portion of the lid. Then, as the molten steel in the tundish is discharged to the mold, the inert gas is injected into the molten steel receiving side. As a result, the molten steel on the molten steel receiving side moves under the partition wall and moves to the immersion nozzle side. In this way, the molten steel head on the immersion nozzle side is kept constant, and only the molten steel head on the molten steel receiving side is lowered. When the molten steel head on the molten steel receiving side is sufficiently lowered, the pressurization of the inert gas is stopped, the molten steel receiving portion of the lid is opened, and molten steel having different components is injected from there to the molten steel receiving side. From the above, it is possible to switch the molten steel while continuing the casting while making the component mixing section as small as possible. Further, the molten steel head on the immersion nozzle side can be kept constant during the switching operation.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional side view showing an example of a tundish device for continuous casting according to the present invention, and FIG. 2 is a schematic view showing a molten steel switching operation stepwise.

The tundish 10 is supplied with the molten steel A in the ladle 50 from above one end, and the molten steel A is poured into the mold 60 by the immersion nozzle 11 protruding downward from the bottom surface of the other end. The immersion nozzle 11 is inserted into the molten steel A inside the mold 60, and the pouring speed of the molten metal into the mold 20 is adjusted by the sliding gate 12.

A vertical partition wall 20 is provided in the tundish 10. The partition wall 20 partitions the inside of the tundish 10 into a dipping nozzle side and a molten steel receiving side, and a minute gap 21 is formed between the tundish 10 and the bottom surface of the tundish so as not to hinder the flow of the molten steel A. The space in the tundish 10 on the side of the immersion nozzle needs to include the space directly above the tundish 10, but it is desirable to make it as narrow as possible in order to make the component mixing part accompanying the switching of molten steel small.

A space on the molten steel receiving side in the tundish 10 is hermetically sealed by a lid 30 except for a gap 21 below the partition wall 20. A molten steel receiving portion 31 is opened in the lid body 30 to receive the molten steel A in the ladle 50. The molten steel receiving portion 31 is opened and closed by a retractable airtight lid 32. The lid 30 is connected to a gas source thereof via a pressurizing pump 41 by a pipe 40 in order to pressurize an inert gas such as Ar into the space on the molten steel receiving side.

When switching the molten steel, first, as shown in FIG. 2A, the injection of the molten steel A into the tundish 10 is stopped and the airtight lid 32 is closed. In this state, the molten steel A remaining in the space on the immersion nozzle side in the tundish 10 is injected into the mold 60, and the head of the mold 60 is lowered. Therefore, at the same time as closing the airtight lid 32, an inert gas such as Ar is press-fitted into the space on the molten steel receiving side through the gas pipe 40 to immerse the molten steel A on the molten steel receiving side from the gap 21 below the partition wall 20. Move to the nozzle side.

By this operation, as shown in FIG. 2B, the molten steel head on the immersion nozzle side is kept constant and only the molten steel head on the molten steel receiving side is lowered. During this time, the injection of the molten steel A into the mold 60 is continued. Then, as shown in FIGS. 2C and 2D, when the molten steel head on the molten steel receiving side falls close to the level of the gap 21, the pressurization of the inert gas is stopped, the airtight lid 32 is opened, and the components are closed. Start to inject the next molten steel B with a different temperature into the molten steel receiving side.

Thus, the molten steel can be switched without stopping the casting into the mold 60. While the molten steel A remaining in the tundish 10 at the time of starting the supply of the molten steel B is discharged from the tundish 10, the components are mixed or the amount of the molten steel is small, so that the composition of the slab is small. The mixing section can be kept small. Further, since the molten steel head on the immersion nozzle side is kept constant throughout the entire period of switching the molten steel, the sliding gate 12 is prevented from extreme movement, which has a great effect on quality.

Further, if the partition wall 20 is moved up and down or the clearance 21 is provided with an up-and-down type opening / closing wall so as to be able to close the clearance 21, the residual steel and a large amount of inclusions and the like It is possible to more reliably prevent the mixing of slag and the mixing of molten steel having different components when the casting is restarted.

[0017]

[Effect of the device]

 As is clear from the above description, the continuous casting tundish device of the present invention can perform switching of molten steel without stopping casting, thereby eliminating time loss associated with switching and improving casting efficiency. In addition, since the molten steel mixing at the time of switching the molten steel is suppressed and the component mixing portion is reduced, the yield reduction due to the discarding of the component mixing portion is suppressed. In addition, the sudden movement of the sliding gate due to the deterioration of the molten steel head is eliminated, and the quality of the slab is improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing an example of a tundish device for continuous casting according to the present invention.

FIG. 2 is a schematic diagram showing a molten steel switching operation step by step.

[Explanation of symbols]

 10 Tundish 11 Immersion Nozzle 20 Partition Wall 21 Gap 30 Lid 31 Molten Steel Receiving Section 32 Airtight Lid 40 Gas Pipe 50 Ladle 60 Mold A, B Molten Steel

Claims (1)

[Scope of utility model registration request] 1. A tundish in which molten steel is supplied from above one end and a dipping nozzle is projected below the other end,
A partition wall for partitioning the inside of the tundish into the immersion nozzle side and the molten steel receiving side while leaving the lower end portion, and a space below the partition wall for sealing the molten steel receiving side in the tundish in an airtight manner,
A tundish apparatus for continuous casting, comprising: a lid body capable of opening and closing a molten steel receiving portion; and an inert gas press-fitting means connected to the space on the molten steel receiving side.