JPH11347697A - Molten metal braking device and continuous casting method - Google Patents

Abstract

(57) [Problem] With the conventional technology, it is not possible to freely set the strength of the static magnetic field in the direction facing the short side mold of the continuous casting mold and apply sufficient braking force to molten steel. SOLUTION: A pair of long side molds 2 arranged to face each other
On the back side of each of the pair of long-side molds 21, 21 in the continuous casting mold 20 having 1, 21 and the short-side molds 22, 22, four pairs of electromagnets 11a to 11d are juxtaposed in the short-side mold facing direction, The eight electromagnets 11a to 11d have magnetic poles 14a to 14d on both ends in the short side mold facing direction, respectively, facing the long side mold facing direction, and the 16 magnetic poles 14a to 14d are arranged in the short side mold facing direction. The molten metal braking device 10 is arranged so that different poles are located on both sides of the immersion position of the immersion nozzle 30 in the continuous casting mold 20 and different poles are positioned in the long-side mold facing direction. As a result, static magnetic fields B _{1a to} B _1d and B _{2a to} B _2d that are opposite to each other in the long side mold facing direction are formed with the immersion position of the immersion nozzle 30 in the continuous casting mold 20 in the short side mold facing direction. Is done.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal braking device for a continuous casting mold and a continuous casting method capable of improving the internal quality of a continuous casting slab.

[0002]

2. Description of the Related Art Generally, in the following description, molten metal is used.
Take molten steel as an example. In the continuous casting of (1), molten steel contained in a tundish is injected into a continuous casting mold via an immersion nozzle.

[0003] In particular, in continuous casting of a flat cast piece such as a slab, a continuous casting mold having a pair of long-side molds and a short-side mold arranged opposite to each other is provided with a so-called two-hole nozzle in a direction opposite to the short-side mold. Inject molten steel in two directions. At this time, the thickness distribution of the unsolidified portion in the slab width direction becomes non-uniform due to the flow of the injected molten steel. For this reason, it has been conventionally known that problems such as uneven center segregation in the slab width direction and an increase in the depth at which nonmetallic inclusions penetrate in the slab drawing direction occur.

Therefore, conventionally, in order to control the flow of molten steel inside the continuous casting mold, mainly the flow of molten steel in the direction opposite to the short side mold, a static magnetic field generator is provided on the back side of each of the pair of long side molds. An electromagnet is placed, and a molten steel having conductivity is injected while forming a static magnetic field between a pair of long side molds, so that the flowing molten steel is controlled by the Lorentz force generated by the so-called Fleming's left-hand rule. 2. Description of the Related Art A technique for reducing the flow velocity of molten steel by applying power is known.

By the way, the static magnetic field formed by the electromagnet exhibits a mountain-shaped distribution which becomes maximum in the central part and attenuates from the central part toward the end in the longitudinal direction. Further, in order to prevent interference with other equipment, the electromagnet arranged in the above technique has to be installed at substantially the same length as the long side mold length in the short side mold facing direction. Therefore, the end of the electromagnet is arranged adjacent to the short side mold, and the strength of the static magnetic field in the vicinity of the short side mold, that is, both ends in the slab width direction is reduced, and the braking force against the flowing molten steel is reduced. It will drop in some parts. Therefore, in the vicinity of the short side mold, a sufficient braking force cannot be applied, and the descending flow velocity of the molten steel increases.

FIG. 5 is an explanatory view of an example of a slab-shaped continuous cast slab 1 obtained by such a continuous casting method. FIG. 5 (a) is a cross-sectional view of the continuous cast slab 1 during casting. 5 (b) is a perspective view showing a longitudinal sectional view of the continuous cast slab 1 during casting, and FIG. 5 (c) is a perspective view schematically showing the state of occurrence of center segregation of the continuous cast slab 1. FIG.

As described above, when sufficient braking force cannot be obtained in the vicinity of the short side mold and the descending flow velocity of the molten steel increases, FIG.
As (a), in the continuous casting slab 1, the solidification proceeds in the region A ranging from both ends e of the distance L ₁ ~L _2, compared to the clotting progress in the area B of the widthwise central portion Become slow. For this reason, as shown in FIG. 5B, the width distribution of the final solidification position is W-shaped (hereinafter, referred to as “W
Type crater end CE ". ), So Fig. 5 (c)
As shown in (1), the degree of center segregation becomes non-uniform in the width direction, and the degree of center segregation at both ends 2 in the width direction where solidification is delayed is deteriorated.

To solve such a problem, a number of methods have been proposed for improving the strength distribution in the width direction of the static magnetic field in the continuous casting mold by reinforcing the strength of the static magnetic field near the short side mold. .

For example, in Japanese Patent Application Laid-Open No. 4-319052, a main coil and an auxiliary coil are provided by sharing an iron core constituting an electromagnet, and a static magnetic field is generated over the entire width of the long side mold by energizing the main coil. In addition, there is disclosed a molten steel braking device that superimposes a static magnetic field in the vicinity of the short side mold by energizing the auxiliary coil to reinforce the strength of the static magnetic field in the vicinity of the short side mold.

In Japanese Patent Application Laid-Open No. 4-344858, an electromagnet having a substantially groove-shaped iron core is arranged on the back side of a long-side mold so that a static magnetic field near the short-side mold is reduced to a static magnetic field at the center. A molten steel braking device that strengthens the steel by 1.2 to 3.0 times is disclosed.

In Japanese Patent Application Laid-Open No. 5-96349, two magnetic field generating coils are provided on the back side of the long side mold and near the short side mold, and the long side mold is opposed to the two short side molds. A molten steel braking device that generates a static magnetic field in the same direction is disclosed.

Japanese Patent Application Laid-Open No. 6-71400 discloses that an electromagnetic coil divided into four parts in a direction opposite to a short-side mold is arranged near a meniscus in the casting direction, and both an alternating current and a direct current are applied to the long side. A molten steel braking device that generates a static magnetic field in a mold facing direction is disclosed.

Japanese Patent Application Laid-Open Nos. 9-262650 and 9-262651 disclose a pair of iron cores arranged to face each other with a continuous casting mold interposed therebetween, and a plurality of iron cores branched from the iron cores and arranged in parallel in the short-side mold opposite direction. A molten steel braking device having a magnetic pole and a coil wound around each magnetic pole has been proposed.

Furthermore, Japanese Patent Publication No. 7-45093 discloses that a movable iron core divided into a plurality of parts in a casting slab pouring direction and a short side mold facing direction is used, and each movable iron core is separated from the slab by an independent drive mechanism. By arranging it to be able to go back and forth,
A molten steel braking device that obtains a desired static magnetic field distribution in a direction opposite to the short side mold has been proposed.

[0015]

However, according to any of these prior arts, a desired static magnetic field distribution can be obtained by freely setting the strength of the static magnetic field in the direction opposite to the short side mold of the continuous casting mold. As a result, a sufficient braking force cannot be applied to the molten steel.

That is, in the molten steel braking device disclosed in Japanese Patent Application Laid-Open No. 4-319052, the main coil is wound around the entire area of one iron core, and the auxiliary coils are wound around both ends. As shown in FIG. 3 of Japanese Unexamined Patent Publication No. 4-319052, the static magnetic field distribution obtained by the main coil is strongly reflected. Therefore, even with this technique, a sharp decrease in the static magnetic field strength, particularly on the outermost end side in the direction facing the short side mold, cannot be eliminated, and a sufficient braking force cannot be obtained near the short side mold.

In the molten steel braking device disclosed in Japanese Patent Application Laid-Open No. 4-344858, FIG.
As shown in (1), since a substantially groove-shaped iron core is used as the electromagnet, the distribution of the static magnetic field intensity is determined by the shape of the iron core. For this reason, the static magnetic field intensity distribution in the direction opposite to the short side mold cannot be freely controlled, and depending on the casting width, a sufficient braking force cannot be applied near the short side mold.

In a molten steel braking device disclosed in Japanese Patent Application Laid-Open No. 5-96349, as shown in FIG. 1 of Japanese Patent Application Laid-Open No. 5-96349, an electromagnet pair is arranged only near each of two short-side molds. Therefore, it is not possible to freely control the static magnetic field intensity on the central portion side in the direction facing the short side mold. Therefore, the braking force on the central portion side is insufficient.

The static magnetic field obtained by the molten steel braking device disclosed in JP-A-6-71400 is disclosed in JP-A-6-71400.
As shown in FIGS. 1 (a) and 1 (b) of JP-A No. 400, in the two regions on the left and right sides of the immersion nozzle immersion position in the short side mold facing direction, the directions are opposite to each other. Therefore, between the static magnetic fields formed in the opposite direction, a position where the static magnetic field intensity becomes zero is inevitably generated, and it is not possible to obtain a sufficient braking force in the short-side mold facing direction. I will.

As shown in FIG. 4 of Japanese Patent Application Laid-Open No. 9-262650, the static magnetic field obtained by the molten steel braking device disclosed in Japanese Patent Application Laid-Open Nos. 9-262650 and 9-262651 Since the magnetic poles have different polarities, they are formed in opposite directions between the opposing magnetic poles. for that reason,
Inevitably, a number of positions where the static magnetic field strength becomes zero occur in the short-side mold facing direction, and it becomes impossible to obtain a sufficient braking force in the short-side mold facing direction.

Further, in the molten steel braking device disclosed in Japanese Patent Publication No. 7-45093, a movable iron core is arranged together with a main iron core as an auxiliary iron core.
As in the case of the molten steel braking device disclosed in Japanese Patent Application Laid-Open No. H10-209, the obtained static magnetic field distribution strongly reflects the static magnetic field distribution obtained by the main coil, and a sufficient braking force cannot be obtained near the short side mold. Further, the need for an iron core advance / retreat drive device complicates the device, resulting in a decrease in maintainability and an increase in equipment costs.

As described above, none of these conventional molten steel braking devices can provide a sufficient braking force to molten steel injected from the immersion nozzle in two directions opposite to the short side mold. The downflow near the side mold cannot be sufficiently damped. For this reason, a uniform downward flow cannot be obtained in the slab width direction, and the unsolidified portion thickness of the slab during casting becomes uneven in the width direction, and the penetration depth of nonmetallic inclusions increases. There's a problem.

Further, in these conventional molten steel braking devices,
If the width of the continuous casting slab is changed during casting by changing the facing distance of the short side mold of the continuous casting mold, it is even more difficult to provide a desired static magnetic field distribution.

FIG. 6 is a graph showing an example of the distribution of the static magnetic field strength formed by these conventional molten steel braking devices in the short side mold facing direction. That is, as shown in the graph in FIG. 6, according to these conventional molten steel brake, the maximum value D of the static magnetic field strength in only the fixed position C in the width direction, for example, the maximum value D ₁ ~ minimum D ₂ It is possible to arbitrarily change the range.

However, since the fixed position C is always fixed even when the casting width, that is, the position of the short side mold with respect to the long side mold is changed, the static position C in the short side mold facing direction corresponding to the change of the casting width. The magnetic field distribution cannot be changed.
Therefore, in the graph shown in FIG. 6, for example, the position of the short side mold with respect to the long side mold is changed from the fixed position C to the changed position D.
When it is changed to, the descending flow velocity of the molten steel in the vicinity of the short side mold cannot be sufficiently reduced, and the resulting continuous cast slab has an uneven unsolidified portion thickness in the width direction.

Here, an object of the present invention is to obtain a desired static magnetic field distribution by freely setting the intensity of the static magnetic field in the direction of facing the short side mold of the continuous casting mold, and thereby to obtain a sufficient braking force on the molten steel. The present invention is to provide a molten metal braking device and a continuous casting method that can provide the following.

It is another object of the present invention to obtain a desired static magnetic field distribution with a relatively simple and inexpensive structure even when the facing distance of the short side mold is changed, thereby obtaining a desired static magnetic field distribution in the vicinity of the short side mold. An object of the present invention is to provide a molten metal braking device and a continuous casting method capable of giving a sufficient braking force to molten steel.

[0028]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a continuous casting mold having a pair of a long side mold and a short side mold which are arranged to face each other. On the back side of each of the pair of long-side molds, a pair of electromagnets are placed on the back side of each of the pair of long-side molds so as to form static magnetic fields opposite to each other in the direction opposite to the long side mold with the immersion position of the immersion nozzle in the mold as a boundary. A molten metal braking device, comprising a plurality of sets arranged side by side.

In the present invention, each of the plurality of electromagnets has a magnetic pole directed toward the long-side mold facing direction at both ends with respect to the short-side mold facing direction, and the plurality of magnetic poles are arranged in the short-side mold facing direction. It is exemplified that the electrodes are arranged such that the different poles are located on both sides of the immersion position of the immersion nozzle and the different poles are positioned in the long-side mold facing direction.

From another viewpoint, the present invention relates to a continuous casting mold having a pair of long-side molds and a short-side mold arranged opposite to each other, and a pair of electromagnets is provided on the back side of each of the pair of long-side molds. A plurality of sets are arranged side by side with respect to the short side mold facing direction, and a plurality of electromagnets each have a magnetic pole directed to the long side mold facing direction at both ends with respect to the short side mold facing direction,
A plurality of magnetic poles are arranged such that different poles are located on both sides with respect to the immersion position of the immersion nozzle with respect to the short side mold facing direction and different poles are located with respect to the long side mold facing direction. It is a metal braking device. With this molten metal braking device, static magnetic fields that are opposite to each other in the long-side mold facing direction are formed with respect to the immersion position of the immersion nozzle in the continuous casting mold in the short-side mold facing direction.

In the molten metal braking device according to the present invention, the plurality of magnetic poles may be arranged in a range including the moving range of the short side mold relative to the long side mold in the short side mold facing direction. Even when the facing distance of the mold is changed, it is desirable to provide sufficient braking force to the molten steel in the vicinity of the short side mold.

Further, from another viewpoint, the present invention relates to a continuous casting mold having a pair of long-side molds and short-side molds which are arranged opposite to each other, on the back side of each of the long-side molds, in the direction opposite to the short-side mold. A plurality of pairs of electromagnets are arranged in parallel, and the plurality of pairs of electromagnets are opposed to each other in the long side mold facing direction with respect to the short side mold facing direction, with the immersion position of the immersion nozzle in the continuous casting mold as a boundary. A continuous casting method characterized by injecting molten metal from an immersion nozzle in two directions substantially parallel to the opposite direction of the short-side mold while forming a static magnetic field.

In the continuous casting method according to the present invention described above, the intensity of the static magnetic field formed by each of the plurality of pairs of electromagnets can be controlled independently of each other. Desirable for application in the mold facing direction.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a molten metal braking device and a continuous casting method according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a molten steel braking device 10 of the present embodiment,
It is a perspective view which shows a partly simplified. As shown in FIG.
The molten steel braking device 10 of the present embodiment is provided in a continuous casting mold 20. Hereinafter, the continuous casting mold 20 and the molten steel braking device 10 will be described separately.

[Continuous Casting Mold 20] The continuous casting mold 20 has an upper portion and a lower portion formed by a pair of long side molds 21 and 21 arranged to face each other and a pair of short side molds 22 and 22 arranged to face each other. Both are formed in a rectangular parallelepiped shape that is open.

The long side mold 21 and the short side mold 22 are both
It is formed in a plate shape by a copper plate having a water cooling mechanism (not shown) inside. In the present embodiment, the opposed long side mold 2
The distance between 1, 21 ie the casting thickness is 235 mm.

A plane facing the inside of the long side mold 21 and the end face of the short side mold 22 on the long side mold 21 side are in contact with each other. In the space defined by 22 and below, two discharge holes 30a, 30a provided in the lower part of the immersion nozzle 30 provided at the bottom of the Injected towards.

The short-side molds 22, 22 are movably arranged in the direction indicated by the white arrow in the drawing with respect to the long-side molds 21, 21 by a known driving mechanism (not shown). Thus, it is possible to change the width of the continuous cast slab to be cast during casting. In this embodiment, the width change during casting is from 1600 mm to 2300 mm.
Within the range. In addition, since this casting width changing technique is well known, the description of the drive mechanism and the like of the short side mold 22 will be described.
Omitted.

(Molten Steel Braking Apparatus 10) The molten steel braking apparatus 10 of this embodiment includes four pairs of electromagnets 11a to 11d arranged on the back sides of the long side molds 21, 21, respectively.

The electromagnets 11a to 11d of the present embodiment are provided with four iron cores 12a arranged side by side in the direction opposite to the short side mold.
12b, 12c, 12d, and coils 13a, 13b, 13c, 13d mounted on both ends of each of the iron cores 12a to 12d.

Each of the iron cores 12a to 12d has a groove-shaped horizontal cross-sectional shape, and has coils 13a to 13d mounted on both ends thereof, and has a long-side mold facing direction at both ends with respect to the short-side mold facing direction. The magnetic poles 14a, 14b, 14c, 14d are formed. Although not shown, an energizing device is provided for each of the coils 13a to 13d mounted on each of the iron cores 12a to 12d so that the energizing amounts to the coils 13a to 13d can be controlled independently of each other. Is composed.

The iron core 12a is provided with two magnetic poles 14 with respect to the center position of the continuous casting mold 20 in the short side mold facing direction, that is, the immersion position of the immersion nozzle 30 in the short side mold facing direction.
a and 14a are arranged so as to be symmetrical.

The iron core 12b is arranged at a predetermined distance outside the iron core 12a such that the two magnetic poles 14b, 14b are symmetrical with respect to the immersion position of the immersion nozzle 30 in the direction facing the short side mold. You.

The iron core 12c is arranged outside the iron core 12b by a predetermined distance so that the two magnetic poles 14c, 14c are symmetrical with respect to the immersion position of the immersion nozzle 30 in the short side mold facing direction. You.

Further, the iron core 12d is separated from the iron core 12c by a predetermined distance so that the two magnetic poles 14d, 14d are symmetrical with respect to the immersion position of the immersion nozzle 30 in the direction facing the short side mold. Be placed.

The two magnetic poles 14a of each of the iron cores 12a to 12d
~ 14d, immersion nozzle in the short side mold facing direction
Magnetic poles 14a arranged on one side with respect to 30 immersion positions
14d is magnetized to the N pole and the magnetic pole 14a arranged on the other side
-14d are magnetized to the south pole. Further, the magnetic poles disposed at positions facing each other in the long-side mold facing direction with the continuous casting mold 20 interposed therebetween are magnetized to have different polarities.

Thus, the molten steel braking device 10 of the present embodiment
According to FIG. 1, as shown by a broken line in FIG.
The static magnetic fields B _1a , B _1b , B
_1c , B _1d and static magnetic fields B _2a , B _2b , B _2c , B _2d can be generated.

The iron core 12a is arranged near the immersion position of the immersion nozzle 30 in the direction of facing the short side mold. In addition, the iron core 12d is, with respect to the short-side mold facing direction,
It is provided in a range including the entire moving range with respect to the long side mold 21 of 22. In this manner, the iron cores 12a to 12d are juxtaposed in the direction in which the short-side mold 22 moves with respect to the long-side mold 21 in the short-side mold facing direction.

Thus, in this embodiment, the electromagnet
The 11a ～11D, between the oppositely disposed long sides molds 21 and 21, opposite of the static magnetic field _{B 1a ~B 1d, B 2a ~B} 2d is generated together.

The molten steel braking device 10 of the continuous casting mold 20 in the present embodiment is configured as described above. Next, a situation in which continuous casting is performed while operating the molten steel braking device 10,
explain.

In the molten steel braking device 10 of the present embodiment, the center position of the continuous casting mold 20 with respect to the short side mold facing direction is symmetrical, and the magnetic poles 14a to 14d arranged side by side in the short side mold facing direction are used to oppose each other. While generating static magnetic fields B _{1a to} B _1d , B _{2a to} B _2d in opposite directions between the long side molds 21, 21, the immersion nozzle 30 outputs a magnetic field B 2 a substantially parallel to the short side mold facing direction.
Inject molten steel in the direction. After that, continuous casting is performed by a known continuous casting technique.

At this time, the magnetic force generated by the magnetic poles 14a to 14d is appropriately adjusted by controlling the amount of current to the coils 13a to 13d independently of each other. Thus, the static magnetic field B _1a .about.B _1d in the short-side mold opposite direction, the intensity distribution of the B _2a .about.B _2d, it is possible to freely adjust. Therefore, a desired static magnetic field distribution can be obtained in the short-side mold facing direction, whereby a sufficient braking force can be applied to the molten steel.

Since the directions of the static magnetic fields B _{1a to} B _1d and B _{2a to} B _2d formed by the molten steel braking device 10 of the present embodiment are opposite to each other, the directions of the continuous casting mold 20 with respect to the short side mold facing direction. In the vicinity of the center position, a part where the static magnetic field is zero will be formed, but the immersion nozzle 30 is immersed in this part and the molten steel is injected in the direction opposite to the short side mold, so that the molten steel in this area There is almost no need to control the flow of water.

Further, according to the molten steel braking device 10 of the present embodiment, as the width of the continuous casting stand to be cast, that is, the facing distance of the short side molds 22, is changed, the inside of the continuous casting mold 20 is changed. Even when the flow condition of molten steel changes, the amount of electricity to each of the coils 13a to 13d is controlled independently of each other, so that the intensity distribution of the static magnetic field in the short-side mold facing direction can be freely adjusted, The braking force against the flow can be varied with respect to the short side mold facing direction. Therefore, a static magnetic field having a desired intensity distribution can always be given even if the facing distance between the short side molds 22, 22 is changed.

FIG. 2 is a graph showing an example of the distribution of the static magnetic field strength applied between the long side molds 21 by the molten steel braking device 10 of the present embodiment in the short side mold facing direction. That is, according to the molten steel braking device 10 of the present embodiment,
As shown in the graph of FIG. 2, even if the installation positions of the short side molds 22, 22 were changed, the short side molds 22, 22 were mounted on the cores 12a to 12d at positions corresponding to the short side molds 22, 22, following the change. Coil 13a
To control the amount of power to 13d. Thereby, the short side mold 2
The strength of the static magnetic field in the vicinity of 2, 22 can be set large, and a static magnetic field distribution in the mold width direction corresponding to a change in the casting width can be obtained.

As a result, a uniform molten steel descending velocity in the width direction can be obtained regardless of the fluctuation of the slab width.
The distribution of the unsolidified thickness in the width direction is made uniform. For this reason, the crater end CE is flattened in the width direction, the distribution in the width direction of the center segregation level and the penetration depth of the nonmetallic inclusions is made uniform, and the internal quality is improved.

According to the molten steel braking device 10 of the present embodiment, the iron cores 12a to 12d and the coils 13a to
13d and the electromagnets 11a to 11d having
Since a desired static magnetic field distribution can be obtained in the direction opposite to the short side mold, an electromagnet having a complicated configuration as disclosed in the above-described related art is not required.

[0059]

EXAMPLES Further, examples of the molten metal braking device and the continuous casting method according to the present invention will be described more specifically.

Using the molten steel braking device 10 of this embodiment shown in FIG. 1, casting was performed while generating static magnetic fields B _{1a to} B _1d and B _{2a to} B _2d in the direction opposite to the long side mold. ). In this embodiment, the casting width is changed under the conditions shown in Table 1, and the magnetic poles 14b at positions corresponding to the short side molds 22, 22 corresponding to the width are set.
, 14c, 14d generate static magnetic fields B _1b , B _2b , B _1c , B
The intensities of _2c , B _1d , and B _2d were set to be 1.5 times the intensity of the other magnetic poles. The magnetic poles 14d outside the positions corresponding to the short side molds 22, 22 were not energized, and no static magnetic fields B _1d , B _2d were generated.

On the other hand, as a comparative example, as shown in Table 1, the intensity of the static magnetic field of the magnetic pole 13c was set to be 1.5 times as high as that of the other magnetic poles, and the conditions for applying the magnetic field were fixed. Then, the casting width was changed.

[0062]

[Table 1]

As described above, with respect to the slab manufactured according to the example, the evaluation result of the width distribution of the center segregation level in the width direction is shown as
FIG. 3 shows a graph. On the other hand, also in the comparative example, the evaluation results are shown in a graph in FIG. The center segregation score was obtained from the result of rank evaluation by visual inspection after polishing the entire cross section of the slab and etching with a 5% by weight-HNO ₃ aqueous solution. 3 and 4 indicate that the casting width is 1600 mm, and Δ indicates that the casting width is 19 mm.
00 mm, and □ indicates 2300 mm.

From the graph shown in FIG. 3, according to the embodiment,
It can be seen that even when the casting width changes, the variation in the distribution of the center segregation in the width direction is significantly suppressed. On the other hand, according to the comparative example, as described above, the static magnetic field strength can be increased near the short side mold 22, but since the position of the magnetic pole 14c is fixed, as shown in the graph of FIG. , Casting width 16
When the short-side mold 22 changes from 00 mm to 2300 mm and moves away from the position where the static magnetic field intensity has the maximum value, the molten steel descending flow velocity in the vicinity of the short-side mold 22 cannot be sufficiently reduced,
As a result, the level of center segregation near the short side in the slab width direction deteriorates.

[0065]

[Modification] In the embodiment and the example, the case where the molten metal is molten steel has been described as an example. However, the present invention is not limited to such an embodiment, and the present invention is not limited to the molten metal having conductivity other than molten steel. Applicable.

Further, in the embodiment and the example, as shown in FIG. 1, a total of eight electromagnets 11a to 11d have a total of 16 magnetic poles 14a to 14d, and a total of 16 magnetic poles 14a to 14d are The north pole and the south pole are respectively located on both sides of the immersion position of the immersion nozzle 30 and the
Although the case where the poles and the S poles are arranged so as to be located is taken as an example, the present invention is not limited to such an aspect. That is, it is sufficient that static magnetic fields that are opposite to each other in the long-side mold facing direction can be formed with respect to the immersion position of the immersion nozzle in the continuous casting mold in the short-side mold facing direction.
The arrangement of 14a to 14d is not limited.

In the embodiment and the example, the case where four pairs of electromagnets 11a to 11d are arranged is taken as an example.
The present invention is not limited to such an embodiment. Similar effects can be obtained when two or more sets of a pair of electromagnets are arranged. The number of the pair of electromagnets may be determined as appropriate in consideration of the controllability of the distribution of the static magnetic field strength in the short-side mold facing direction, the manufacturing cost, and the like.

[0068]

As described above in detail, according to the present invention, the desired static magnetic field distribution can be obtained by freely setting the strength of the static magnetic field in the short casting mold facing direction of the continuous casting mold. A sufficient braking force can be given to molten steel.

Further, according to the present invention, with a relatively simple configuration, even when the facing distance of the short side mold is changed, a desired static magnetic field distribution can be obtained, whereby the molten steel in the vicinity of the short side mold can be obtained. Can provide a sufficient braking force.

Thus, the unsolidified thickness of the slab during casting can be flattened in the width direction, and the center segregation can be made uniform in the width direction. The significance of the present invention having such effects is remarkable.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a partially simplified molten steel braking device according to an embodiment.

FIG. 2 is a graph showing an example of a distribution of a static magnetic field intensity applied between long side molds in a direction opposite to a short side mold by the molten steel braking device of the embodiment.

FIG. 3 is a graph showing the results of Examples.

FIG. 4 is a graph showing a result of a comparative example.

FIG. 5 is an explanatory view of an example of a slab-shaped continuous cast slab obtained by a continuous casting method. FIG. 5 (a) is a perspective view showing a cross section of the continuous cast slab during casting, and FIG. FIG. 5B is a perspective view showing a longitudinal sectional view of the continuous cast slab during casting, and FIG. 5C is a perspective view schematically showing the state of occurrence of central segregation of the continuous cast slab.

FIG. 6 is a graph showing an example of the distribution of the static magnetic field intensity applied between the long side molds according to the conventional technique in the short side mold facing direction.

[Explanation of symbols]

10 Molten metal braking device 11a to 11d Electromagnet 12a to 12d Iron core 13a to 13d Coil 14a to 14d Magnetic pole 20 Continuous casting mold 21 Long side mold 22 Short side mold 30 Immersion nozzle B _{1a to} B _1d , B _{2a to} B _2d Static magnetic field

Claims (4)

[Claims] 1. A long-side mold having a pair of a long-side mold and a short-side mold arranged opposite to each other, and a long-side mold located at a boundary of an immersion nozzle of the continuous mold in the short-side mold facing direction with respect to a facing direction of the short-side mold. Molten metal, in which a plurality of pairs of electromagnets are arranged side by side with respect to the short side mold facing direction on the back side of each of the pair of long side molds so as to form static magnetic fields opposite to each other in the facing direction. Braking device. 2. A plurality of pairs of electromagnets are arranged on the back side of each of the pair of long-side molds in the continuous casting mold having a pair of long-side molds and short-side molds arranged to face each other in the short-side mold facing direction. The plurality of electromagnets,
Each has a magnetic pole directed toward the long-side mold facing direction at both ends with respect to the short-side mold facing direction, and a plurality of the magnetic poles,
It is arranged such that different poles are located on both sides with respect to the immersion position of the immersion nozzle in the continuous casting mold with respect to the short side mold facing direction and different poles are located with respect to the long side mold facing direction. And the molten metal braking device. 3. The molten metal braking device according to claim 2, wherein the plurality of magnetic poles are arranged in a range including a moving range of the short side mold with respect to the long side mold with respect to the short side mold facing direction. 4. A continuous casting mold having a pair of long-side molds and a short-side mold arranged to face each other, and a plurality of electromagnet pairs are juxtaposed in the short-side mold facing direction on the back side of each of the long-side molds. In advance, by a plurality of such electromagnet pairs,
From the immersion nozzle to the short-side mold facing direction, while forming static magnetic fields opposite to each other in the long-side mold facing direction with respect to the immersion position of the immersion nozzle in the continuous casting mold with respect to the short-side mold facing direction. A continuous casting method characterized by injecting molten metal in two directions substantially parallel to the above.