JP2556562Y2 - Pipe stopper for continuous casting tundish - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe stopper for a continuous casting tundish, and more particularly to a pipe stopper which can easily stop and restart the flow of molten steel from a tundish nozzle.

[0002]

2. Description of the Related Art FIG. 9 shows a conventional general steel making process.
In the steel making process of FIG. 9, when the type of steel changes,
After the casting is completed, the tundish 2 serving as a tray for distributing molten steel from the ladle 4 to the plurality of molds 6 is drained and cooled once, and the refractory constructed inside the steel shell of the tundish 2 After repairing No. 8 and setting the sliding nozzle 10, the tundish 2 was burned with a burner 12 to about 1200 °.
C is preheated, the next molten metal 14 is injected, and casting is restarted. In this case, the shortest time from the end of casting to the restart is about 24 hours. FIG. 10 shows a hot recycling method that has been recently studied. In this method, after the casting is completed, the tundish 2 is moved in a hot state without cooling so as not to disturb the work, a sequencer (linking material) 18 is set during that time, and then the tundish 2 is moved again to the original position. And restart casting again,
This method is intended to reduce the heat loss of refractories and molten steel and to omit the maintenance work of the tundish 2.

As a method of controlling the flow rate of the molten metal from the tundish, a sliding nozzle plate method of controlling a nozzle opening area by a nozzle plate 20 capable of sliding as shown in FIG. 11 or a nozzle as shown in FIG. There are an open injection method in which the flow rate is determined only by the hole diameter and the molten steel height (static pressure), and an upper stopper method. However, in the sliding nozzle plate method and the open injection method, it is necessary to stop pouring with a small amount of molten steel remaining in the tundish nozzle so that the slag does not enter the mold. Because
Sliding nozzle plate method and open injection method
It cannot be used in the hot recycling method as shown in FIG.

[0004]

[Problems to be Solved by the Invention] The conventional hot recycling method has the following problems. I. In the case of an iron stopper, it is necessary to stop pouring with a small amount of molten metal remaining in the tundish nozzle so that the slag does not enter the mold, and the stopper head solidifies with the residual metal, making it impossible to reopen the nozzle . B. If a stopper made of refractory material is used, it is possible to reopen the nozzle.However, it is almost impossible to raise the stopper with human power, which is not desirable in terms of safety. , Which increases costs.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pipe for a continuously cast tundish which can reopen a tundish nozzle, does not require pulling up, can safely and efficiently mount a pipe stopper, and does not involve dangerous work. It is to provide a stopper.

The present invention for achieving the above object is as follows. A tapered portion having a tapered outer diameter surface that rubs with the nozzle inner diameter surface of the tundish, a thick pipe portion connected at one end to the large diameter end of the tapered portion, and at the other end of the thick pipe portion A thin pipe portion having a smaller thickness than the thick pipe portion and a thick pipe portion or an inner periphery of the thin pipe portion are provided at positions radially opposed to each other, and are mutually opposed in a pipe stopper axial direction. A slit stopper for continuous casting tundish, comprising: a slit structure portion comprising two plates provided at intervals and parallel to each other.

[0007]

In order to prevent the slag from flowing into the mold, the taper of the pipe stopper is inserted into the nozzle with a small amount of molten metal remaining at the bottom of the tundish, and the outflow of molten steel is stopped.
At this time, the thick pipe portion comes into contact with the remaining hot water in the tundish, but the heat retained by the remaining hot water cannot melt the thick pipe portion, so that casting can be stopped. In this case, if the pipe is thin over the entire length, the remaining hot water melts the pipe stopper and casting cannot be stopped. However, in the present invention, since the lower portion is a thick pipe, casting can be stopped.

The next new molten steel is poured from the ladle. Before the level of molten metal rises to reach the thin-walled pipe, and further rises to the top of the thin-walled pipe, the thin-walled pipe is melted by the retained heat of the molten metal and the molten metal below the uppermost slag layer is cast. It flows into the inside, and eventually the thick-walled pipe and all the tapered parts are melted. In this case, if the pipe is thick over the entire length, the level of pouring will rise to the top of the pipe before the pipe melts, and slag will flow into the mold from the upstream of the pipe. Since only the lower portion has a thick pipe portion, casting can be resumed without inflow of slag. Also, in the pipe stopper method of the present invention, the pipe stopper is not pulled up and the pipe stopper is melted, so that no hydraulic device is required and no dangerous work is involved. In addition, at the time of mounting, the pipes are provided at positions inside the thick pipe section or the thin pipe section radially opposite to each other, and are spaced apart from each other in the pipe stopper axial direction and parallel to each other. Since the mounting structure can be detachably inserted into the slit structure since it has the slit structure composed of two plates, the pipe stopper can be safely mounted on the tundish in a high temperature state.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to FIGS. 1 to 3, a pipe stopper 24 for a continuous casting tundish according to an embodiment of the present invention.
(Hereinafter, simply referred to as a pipe stopper) is made of metal and has a tapered portion 26, a thick pipe portion 28, and a thin pipe portion 30.
And consisting of

The tapered portion 26 has a tapered outer diameter surface having a shape and a size that rubs with the nozzle inner diameter surface of the tundish, and can be manufactured from a commercially available steel reducer. The thick pipe portion 28 is welded at one end to the large-diameter end of the tapered portion 26 and can be manufactured from a commercially available thick steel pipe. The thickness is set to a thickness that will not melt even with a steel type having a high molten steel temperature due to the retained heat of the remaining molten metal.
Thick pipes are suitable for use. In addition, the length is set to be larger than the depth of the normal remaining hot water, for example, 200 mm.

The thin pipe portion 30 is welded at one end to the other end of the thick pipe portion 28 (the end opposite to the side connected to the tapered portion), and can be manufactured from a commercially available thin steel pipe. The thickness is such that even when pouring a steel type having a low molten steel temperature, when the pouring level rises, the molten steel easily melts within a predetermined time due to the retained heat of the molten steel, for example, 1.6 mm.
Heavy steel pipes are suitable for use. Further, the length is appropriately increased so that the rising molten metal level does not reach the upper end of the pipe before the thin pipe portion is melted, and is, for example, 100 mm.

Regarding the selection of the pipe wall thickness, FIGS.
This will be described in more detail with reference to FIG. FIG. 4 shows a state in which the casting is stopped by inserting the pipe stopper 24 into the nozzle 32 of the tundish 2, and FIG.
4 shows that molten steel has started to flow into the mold.

[0013] As shown in FIG.
In the case of a steel stopper having a high molten steel temperature, a pipe stopper made of a thin-walled pipe having a thickness of mm may elute the pipe early, and slag flows into the nozzle together with the molten steel. on the other hand,
In the case of a B type steel having a low molten steel temperature, a pipe stopper composed of a thick pipe having a thickness of 5.5 mm over its entire length has a disadvantage that the elution time of the pipe is delayed and slag flows in from the opening of the pipe. The embodiment of the present invention is a pipe stopper for a two-stage thick pipe in which both problems are corrected. That is, even in the case of the A steel type having a high molten steel temperature, the presence of the thick pipe portion 28 prevents early pipe elution, and also in the case of the B steel type having a low molten steel temperature, the inflow of the thin pipe portion 30 is prevented. You.

The pipe stopper 24 further has a slit structure 34 as shown in FIGS. The slit structure part 34 is desirably provided in the thick pipe part 28 (the thin pipe part 30 may be used). The slit structure 34 includes an arm 4 that supports the pipe stopper 24.
2 which are provided at radially opposed portions of the inner periphery of the thick pipe portion 28 and are provided at intervals in the axial direction of the pipe stopper and in parallel with each other. Plates 36 and 38 are provided.
The slit between the two plates 36, 38 is open in the circumferential direction.

The slit structure portion 34 is provided with the pipe stopper 2
When mounting 4 on the tundish nozzle 32, the arm 42 of the mounting tool 40 is inserted into the slit and used to support the pipe stopper 24. That is, FIGS.
As shown in FIG. 7, after the arm 42 is engaged with the slit to support the pipe stopper 24 and is mounted on the tundish nozzle 32, the mounting tool 40 is turned in the direction of the arrow in FIG. Remove and put on the attachment 40
Remove only.

Next, the operation will be described. When the casting is finished, the pipe stopper 24 is mounted on the tundish nozzle 32 using the mounting tool 40. The tundish 2 is shifted laterally from above the mold, and the partition plate and the joint plate are placed in the mold. Next, the tundish 2 is moved laterally, returned to the mold, and poured into the tundish 2 from a ladle. When the molten steel rises to the middle of the thin stopper portion 30, the pipe stopper 24 elutes, and the casting is restarted. At this time, since the elution portion is below the slag portion, no slag flows into the mold. Eventually, the entire pipe stopper 24 melts. Therefore, there is no need to raise the pipe stopper. In this case, the tundish cycle time from the end of casting to the restart is about 8 minutes at the shortest. This hot recycling method has the advantages that the casting end-restart time can be greatly reduced and that the oil or gas for preheating can be largely saved because the tundish is not once cooled.

[0017]

According to the present invention, the following effects are obtained because the pipe stopper has the thick pipe, the thin pipe, and the slit structure. I. Casting can be completed and restarted without inflow of slag.In restarting, the entire pipe stopper is melted by the retained heat of the molten steel poured, so the pipe stopper solidifies with the residual metal and restarts the nozzle. There is no phenomenon that makes the mouth impossible. B. Since the pipe stopper is melted without being pulled up, a hydraulic device for pulling up the pipe stopper and dangerous work of pulling up can be eliminated. C. The slit structure consists of two plates provided at intervals in the axial direction of the pipe stopper and parallel to each other, so that the mounting tool can be inserted in a detachable manner and the pipe can be inserted into the tundish in a hot state. The stopper can be mounted safely without being affected by high temperatures.

[Brief description of the drawings]

FIG. 1 is a perspective view of a pipe stopper for a continuous casting tundish according to an embodiment of the present invention.

FIG. 2 is a sectional view of the pipe stopper of FIG. 1;

3 is a plan view of the pipe stopper of FIG. 2 as viewed from the thin pipe portion side in the axial direction.

FIG. 4 is a sectional view showing a state in which a pipe stopper is mounted on a tundish nozzle.

FIG. 5 is a cross-sectional view showing a state where a pipe stopper has started to elute.

FIG. 6 is a partial cross-sectional view showing a state where the wearing tool is engaged with the slit structure.

FIG. 7 is a plan view of the slit structure and the mounting device of FIG. 6;

FIG. 8 is an operation comparison diagram of the pipe stopper of the present invention and an imaginary pipe stopper which is thin and thick over its entire length.

FIG. 9 is a process chart of a conventional steelmaking method.

FIG. 10 is a process chart of the hot recycling method.

FIG. 11 is a partial sectional view near a tundish nozzle of a sliding nozzle plate method.

FIG. 12 is a partial cross-sectional view near the tundish nozzle of the open injection method.

[Explanation of symbols]

 2 Tundish 24 Pipe stopper 26 Taper part 28 Thick pipe part 30 Thin pipe part 32 Tundish nozzle 34 Slit structure part 36 Plate 38 Plate 40 Fitting

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) The creator, Tsugio Shimono 5-9, Yonbancho, Chiyoda-ku, Tokyo Topy Industries Co., Ltd. (72) The creator Kazunori Tomita 5-9, Yonbancho, Chiyoda-ku, Tokyo Industrial shares In-house (72) Inventor Satoshi Kato 5-9, Yonbancho, Chiyoda-ku, Tokyo Topy Industries Co., Ltd. (72) Inventor Noriyuki Watanabe 5-9, Yonbancho, Chiyoda-ku, Tokyo Topy Industries Co., Ltd. (56) Reference Document JP-A-63-40651 (JP, A) Japanese Utility Model Application Sho-54-155913 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A tapered portion having a tapered outer diameter surface that rubs with a nozzle inner diameter surface of a tundish; a thick pipe portion connected at one end to a large diameter end of the tapered portion; A thin pipe portion connected to the other end of the portion and having a smaller thickness than the thick pipe portion; and a pipe provided at a position radially opposed to the inner periphery of the thick pipe portion or the thin pipe portion. And a slit structure portion comprising two plates provided at intervals in the stopper axial direction and parallel to each other, and a pipe stopper for a continuous casting tundish.