JPH01178352A - Method for continuously casting slab - Google Patents

Abstract

PURPOSE:To enable continuous casting without lowering the productivity of narrow width slab with the min. reconstruction of equipment by arranging two tundish nozzles and separately one more tundish nozzle at near the center side in the adjoining three strands of the narrow width molds. CONSTITUTION:The tundish nozzles 3a and 4a arranged at span (l) for using at the time of casting with two strands of wide width molds are used as they are. At the same time, among the narrow width twin molds 7 and 8 for four strands, for example, the narrow width mold 8B at one end of the mold 8 is stopped and the tundish nozzle 3b is used, and as the adjoining narrow width molds 7A, 7B and the other side narrow width mold 8A are poured, the continuous casting can be executed without changing the length L of the tundish. As need of the reconstruction is only arrangement of the tundish nozzle 5b, the reconstruction cost can be lowered.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for continuous casting of slabs, and more specifically, to a method for continuously casting slabs, and more specifically, to a method for continuously casting slabs, which reduces productivity when pouring into a narrow mold defined by partitioning a wide mold. The present invention relates to a continuous slab casting method that allows for minimal modification of equipment.

<Prior art> In a conventional two-strand slab continuous caster, the molten steel 2 in the tundish l has a length as shown in Fig. 3.
The slab is poured by immersing two tandem nozzles 3a and 4a, which are spaced apart from each other by a distance l on the left and right, and immersion nozzles 5 and 6, which are respectively attached below, into the center of molds 7 and 8. 9 and 10 are continuously cast.

By the way, in continuous slab casting, it is required to produce slabs having various widths such as wide slabs and narrow slabs. For example, the following method is used to switch from a wide slab to a narrow slab.

(I) A method of continuously casting narrow convergence slabs using a two-strand mold.

In this method, a pair of short side walls sandwiched between opposing long side walls is reduced to a desired width, and a narrow slab is cast using two strands as they are.

(2) Continuous casting method in which short walls are placed in a wide mold.

In this method, a pair of short side walls and a partition short side wall are sandwiched between opposing long side walls to define a narrow mold, and the number of strands is increased to cast a narrow slab.

<Problems to be Solved by the Invention> The method (1) above is easy to operate and is the most commonly used method, but as shown in Figure 3, a pair of widely set molds are used. When casting with the pair of short side walls 7a of 7 and the short side wall 8a of mold 8 narrowed, the pair of short sides 7a and 8a are moved toward the center centering on the immersion nozzles 5 and 6 to achieve the desired width. Shrink it to and cast it with systland.

In the case of this method, for example, in a mold that can cast slabs up to a width of about 2300 tm, the short side wall is reduced to 10
There is a problem in that when a slab of about 00 seconds is cast, the productivity of the slab is extremely reduced.

In order to solve the above-mentioned problem of reduced productivity, the so-called twin casting method has been proposed, in which continuous casting is performed using the partition short side walls described above (2). As shown in FIG. 4, this method consists of narrow twin molds 7 and 8, which are defined by inserting partition short side walls 7b and 8b between a pair of wide mold short side walls 7a and 8a, respectively. This allows for continuous casting as four strands while ensuring productivity.

In this case, tundish nozzles 3a, 3b and 4a are installed in tundish 1 to pour the melt into twin molds 7 and 8 that constitute four strands.

4b and an immersion nozzle 5a installed directly below it.

5b, 6a, and 6b must be located at the center of each narrow mold in order to equalize the pouring supply.

If you try to use the span l of tundish nozzles 3 and 4 without changing the span l of tundish nozzles 3 and 4 in continuous casting using the two-strand wide mold 7.8 shown in Fig. 3, and install the remaining two tundish nozzles in tundish 1, It becomes necessary to increase the span of the tundish nozzles at both ends, and the existing long tundish nozzle cannot be used, so the length of the tundish nozzle must be increased. In order to increase the length of the tanditsu to the desired length L + α, it is necessary to newly install the tanditsu including incidental equipment, or to modify the tanditush and the device for repairing the kundish, which results in a large amount of cost. There is.

The problem can be solved by moving the mold closer to the center of the tundish, but this requires major modification of the continuous casting machine, which is not practical.

For example, the technology related to twin casting is disclosed in Japanese Unexamined Patent Application Publication No. 1983.
Although it is disclosed in Publication No. 151142, if one of the two strands is cast in a narrow twin mold and the other is cast in a wide mold as shown in Figure 1 of the same publication, it is the same as the above case and the existing two It is impossible to implement this without changing the span 2 of the tundish nozzles 3 and 4 of the strand, and the above-mentioned problems cannot be solved.

The present invention solves the above conventional problems and improves productivity by using a twin mold in which a partition plate is inserted into a wide mold while maintaining the length of the existing tundish and the span 2 of the tundish nozzle in the two-strand method. It is an object of the present invention to provide a method for continuous casting of slabs that does not cause dropping and can minimize modification of equipment.

Means for Solving the Problems> The configuration of the present invention for achieving the above object will be explained based on FIGS. 1 and 2. 3a, 4
The above-mentioned wide mold 7 in a wide slab continuous casting machine in which melt is poured into two strand wide molds 7 and 8 from a.
and a pair of short side walls 7a and 8a and a pair of partition short side walls 7b and 8b are sandwiched between the opposing long side walls 7c and the long side wall 8c of 8, respectively, to form a 4-strand narrow mold 7A, 7B, 8A, and 8B, and the two above-mentioned narrow molds 7A, 7B, and 8A are formed in the narrow molds of three adjacent strands except mold 8B at one end among the four strands of narrow molds 7A, 7B, and 8A, and 8B. Molten metal is poured from the tundish nozzles 3a, 4a and another tundish nozzle 3b separately arranged near the center of the tundish 1.

Function> Since the present invention has the above-mentioned configuration, the tundish nozzles 3a and 4a (see Fig. 3), which are disposed apart from the span 2 used when casting a two-strand wide mold, can be If you use it as is, you can also use Tanditshu 1.
For example, among the narrow twin molds 7 and 8 of 4 strands from another tundish nozzle 3b separately arranged on the center side of the
and adjacent narrow molds 7A, 7B and 8A.
Since the molten metal is poured into the tundish, continuous casting can be performed without changing the length of the tundish. Since the only thing that requires modification is the provision of the tundish nozzle 5b, the cost of modification can be reduced.

In addition, since it is possible to produce narrow slabs with three strands whose drawing speed is relatively high compared to the production of wide slabs with two strands whose drawing speed is low, continuous casting can be performed without reducing productivity.

Although FIGS. 1 and 2 show the case of continuous casting of narrow slabs having the same width, there is no problem in carrying out casting with the widths of each strand being changed.

<Example> Hereinafter, the present invention will be described with reference to an example shown in FIGS. 1 and 2. Tundane insulator 1 has a span suitable for casting a two-strand wide slab. Holding the tundish nozzles 3a and 4a, the narrow mold 7A
and 8A. Further, a separate tundish nozzle 3b is disposed near the center of the tundish I so as to correspond to the center of the narrow mold 7B.

On the other hand, a pair of short side walls 7a and 8 are provided between the opposing long side walls 7c and 8c of the wide molds 7 and 8, respectively.
A narrow mold 7A of 4 strands is made by sandwiching the inner partition short side walls 7b and 8b.

7B, 8A, and 8B are defined.

The tundish nozzles 2 in the tundish 1 are immersed nozzles 5a respectively attached from the adjacent tundish nozzles 3a, 3b and 4a.

The molten metal is poured into narrow molds 7A, 7B and 8A through 5b and 6a to cast narrow slabs 9a, 9b and 10a. In this case, the narrow mold 8B at one end is out of the length range of the tundish, so it is stopped and not used.

As a result of the continuous casting method of narrow slabs as described above,
In a continuous casting machine capable of casting a wide slab of 2800 m wide, a narrow slab of 800 to 1000 m wide could be continuously cast without reducing productivity by making a small modification by simply installing a tundish nozzle 5b.

When switching from narrow slab casting to wide slab casting, after the narrow slab casting is completed, the tundish nozzle 3b of the tundish 1 is closed with a refractory, and then the tundish 1 is changed to the state shown in FIG. The molten steel 2 inside is passed through the tundish nozzles 3a, 4a and the immersion nozzles 5a, 6a installed below them to the partition walls 7b, 8.
It is sufficient to cast in wide molds 7 and 8 without b.

<Effects of the Invention> Since the present invention is a method as described above, it is possible to achieve the effect that narrow slabs can be continuously cast without reducing productivity with minimal modification of equipment.

4. Brief explanation of the drawings.

1 and 2 are a cross-sectional view and a perspective view showing an embodiment of the present invention, FIG. 3 is a cross-sectional view showing a conventional example of wide slab casting, and FIG. 4 is a conventional example of narrow slab casting. FIG.

1...Tanditshu, 2...molten steel, 3.4...Tanditshu nozzle, 5.6...Immersion nozzle, 7.8...mold, 9.10...Slab.

Patent applicant: Kawasaki Steel Corporation Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] In a wide slab continuous casting machine in which melt is poured into a two-strand wide mold from two tundish nozzles arranged in a tundish, a pair of short side walls and a partition are provided between the opposing long side walls of the wide mold. Hold the short side wall 4
A narrow mold of strands is defined, and the two tundish nozzles and the center side of the tundish are connected to the narrow mold of three adjacent strands except for one end of the narrow mold of the four strands. A continuous slab casting method characterized by pouring metal from another tundish nozzle installed nearby.