JP2003266159A - Electromagnetic stirrer and method for continuous casting - Google Patents

Abstract

(57) [Summary] [PROBLEMS] An electromagnetic coil can be replaced during casting.
Moreover, the present invention provides an electromagnetic stirring device and a magnetic stirring method for continuous casting that can move in the longitudinal direction of a slab. SOLUTION: 1 or 2 is added to molten steel in a slab of a continuous casting machine.
In the electromagnetic stirrer for continuous casting which stirs the molten steel by applying the moving magnetic field generated by the above-described electromagnetic coil, the electromagnetic coil may be constituted by a pair of U-shaped electromagnetic coils provided on the outer periphery of the cast piece. Characteristic electromagnetic stirrer for continuous casting. Preferably, there is provided means for moving the electromagnetic coil in a longitudinal direction of the slab.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting electromagnetic stirrer and a method for stirring molten steel in a mold of a continuous casting machine.

[0002]

2. Description of the Related Art Conventionally, in order to obtain a slab having excellent surface quality by positively levitating and removing non-metallic inclusions and gas contained in molten steel injected into a mold of a continuous casting machine. , A method of electromagnetically stirring molten steel in a mold is known,
For example, it is disclosed in Japanese Patent Laid-Open No. 50-23337. FIG. 1 is a diagram showing a conventional electromagnetic stirrer for continuous casting. The molten steel in the tundish of FIG. 1 is poured into the mold 1 from the lower part of the tundish and cast into a cast piece 2.

Two electromagnetic coils 3 are installed on the outer periphery of the cast piece 2 in the lower part of the mold 1 in the solidification process, and the molten steel 4 inside the cast piece 2 is placed.
Is stirred by a rotating magnetic field generated by the electromagnetic coil 3. By stirring molten steel 4, non-metallic inclusions and gas in molten steel 4 float, and by removing these, internal cracking and segregation of the cast piece can be prevented. In order to effectively apply a stirring force to the molten steel 4 by this electromagnetic stirrer, the electromagnetic coil 3 needs to be as close as possible to the slab 2, so that the conventional electromagnetic coil 3 has a ring shape surrounding the slab 2. It had been.

FIG. 2 is a sectional view of a conventional ring-shaped electromagnetic coil. A conventional continuous casting electromagnetic coil 3 is shown in FIG.
Since the slab 2 passes through the inside during casting because of the ring shape as shown in FIG. 3, it was not possible to replace the electromagnetic coil 3 during casting. Further, since the optimum position of the electromagnetic coil 3 in the longitudinal direction of the slab 2 differs depending on the casting conditions, it is preferable to install the electromagnetic coil 3 in the optimum position. In the case of moving the guide roll 5 for the slab 2 or the dummy bar installed on the lower surface of the slab 2 as an obstacle, it is necessary to replace these guide rolls 5 together with the electromagnetic coil. It was

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the prior art as described above, the electromagnetic coil can be exchanged during casting, and the continuous casting can move in the longitudinal direction of the cast piece. An object of the present invention is to provide an electromagnetic stirring device and a method for electromagnetic stirring.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides an electromagnetic stirrer for continuous casting and a method for electromagnetic stirrer, in which the electromagnetic coil can be replaced during casting and the electromagnetic coil can be moved in the longitudinal direction of the slab. The gist is the following contents as described in the claims.

(1) In a continuous casting electromagnetic stirrer for stirring a molten steel by applying a moving magnetic field generated by one or more electromagnetic coils to the molten steel in a slab of a continuous casting machine, the electromagnetic coil is An electromagnetic stirrer for continuous casting, comprising a pair of U-shaped electromagnetic coils provided on the outer periphery of the slab. (2) The electromagnetic stirrer for continuous casting according to (1), which has a means for moving the electromagnetic coil in the longitudinal direction of the slab.

(3) An electromagnetic stirring method using the electromagnetic stirring device for continuous casting according to (1), wherein the electromagnetic coil is retracted in the thickness direction or the width direction of the slab to thereby reduce the electromagnetic force during casting. An electromagnetic stirring method characterized in that a coil is replaced. (4) An electromagnetic stirring method using the electromagnetic stirring device for continuous casting according to (2), wherein the electromagnetic coil is moved to a position corresponding to a casting condition in a longitudinal direction of the cast slab, An electromagnetic stirring method, wherein a moving magnetic field is applied to molten steel to stir the molten steel.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an electromagnetic stirring apparatus and an electromagnetic stirring method according to the present invention will be described in detail with reference to FIGS. (First Embodiment) FIG. 3 is a cross-sectional view of an electromagnetic stirrer using an electromagnetic coil retracting in the thickness direction of a cast piece according to the present invention, as seen from the longitudinal direction of the cast piece. A pair of U-shaped electromagnetic coils consisting of an A electromagnetic coil 6 and a B electromagnetic coil 7 are installed on the outer periphery of the slab 2. In the conventional ring-shaped electromagnetic coil, the electromagnetic coil could not be replaced during casting, but the U-shaped A electromagnetic coil 6 and B electromagnetic coil 7 of the present invention were used.
Since the electromagnetic coil can be retracted in the thickness direction of the slab, the electromagnetic coil can be replaced even during casting.

The A electromagnetic coil 6 and the B electromagnetic coil 7
To generate a moving magnetic field at A
8, −W9, X10 are generated, and currents are applied to the B electromagnetic coils 7 so as to generate magnetic pole phases −V11, W12, −X13. As a result, a rotating magnetic field acts on the slab 2 and the molten steel 4 inside the slab 2 can be stirred by the action of this rotating magnetic field. FIG. 4 is a cross-sectional view of the slab viewed from the longitudinal direction when the electromagnetic coil in the electromagnetic stirrer of the present invention is at the retracted position. A electromagnetic coil 6
It is understood that the electromagnetic coils 6 and 7 can be exchanged even during casting by supporting the B electromagnetic coil 7 and the B electromagnetic coil 7 on the retracting guide 14 and retracting them in the thickness direction of the slab.

(Second Embodiment) FIG. 5 is a bird's-eye view of an electromagnetic stirrer using an electromagnetic coil retracting in the width direction of a cast piece according to the present invention. A electromagnetic coil 6 and B on the outer periphery of the slab 2.
A pair of U-shaped electromagnetic coils composed of the electromagnetic coil 7 is installed. In the conventional ring-shaped electromagnetic coil, it was not possible to replace the electromagnetic coil during casting, but the U-shaped A magnetic coil 6 and B electromagnetic coil 7 of the present invention have the width direction of the slab 2 as shown in FIG. The electromagnetic coil can be replaced even during casting because it can be evacuated.

In order to retract the A electromagnetic coil 6 and the B electromagnetic coil 7, a retracting guide 14 is provided, and the electromagnetic coils are moved by the casting direction rails 15 and 16 in the longitudinal direction of the slab to set the casting conditions. By placing the A electromagnetic coil 6 and the B electromagnetic coil 7 close to the slab 2 at the optimum position according to the above conditions, the guide roller 5 of the slab or the dummy bar can be avoided and the optimum electromagnetic stirring position suitable for the operating conditions can be obtained. The electromagnetic stirrer can be operated at.

[0013]

INDUSTRIAL APPLICABILITY As described above, the electromagnetic stirrer and the electromagnetic stirrer according to the present invention allow the electromagnetic coil to be replaced during casting, and the electromagnetic coil can be moved in the longitudinal direction of the slab for continuous casting. By providing an apparatus and a magnetic stirring method, the industrially useful remarkable effects are achieved.

[Brief description of drawings]

FIG. 1 is a view showing a conventional electromagnetic stirrer for continuous casting.

FIG. 2 is a cross-sectional view of a conventional ring-shaped electromagnetic coil.

FIG. 3 is a cross-sectional view of an electromagnetic stirrer using an electromagnetic coil that retracts in the thickness direction of the slab according to the present invention, as seen from the longitudinal direction of the slab.

FIG. 4 is a cross-sectional view of the slab viewed from the longitudinal direction when the electromagnetic coil in the electromagnetic stirrer of the present invention is in the retracted position.

FIG. 5 is a bird's-eye view of an electromagnetic stirrer using an electromagnetic coil that retracts in the width direction of a slab according to the present invention.

[Explanation of symbols]

1: Mold 2: Slab 3: Electromagnetic stirrer 4: Molten steel 5: Guide roller 6: A electromagnetic coil (thickness direction or width direction of slab) 7: B electromagnetic coil (thickness direction or width direction of slab) 8: Magnetic pole V 9: Magnetic pole-W 10: Magnetic pole X 11: Magnetic pole-V 12: Magnetic pole W 13: Magnetic pole-X 14: Evacuation guide 15, 16: Rails for casting direction

Claims (4)

[Claims] 1. A molten steel in a slab of a continuous casting machine, 1 or 2
In the continuous casting electromagnetic stirring device for stirring the molten steel by applying a moving magnetic field generated by the above electromagnetic coil, the electromagnetic coil is composed of a pair of U-shaped electromagnetic coils provided on the outer periphery of the cast piece. A characteristic electromagnetic stirrer for continuous casting. 2. The electromagnetic stirrer for continuous casting according to claim 1, further comprising means for moving the electromagnetic coil in a longitudinal direction of the slab. 3. An electromagnetic stirring method using the electromagnetic stirring device for continuous casting according to claim 1, wherein the electromagnetic coil is retracted in a thickness direction or a width direction of a cast piece during the casting. A method of electromagnetic stirring, characterized in that: 4. An electromagnetic stirring method using the electromagnetic stirrer for continuous casting according to claim 2, wherein the electromagnetic coil is moved to a position in accordance with a casting condition in the longitudinal direction of the cast piece. An electromagnetic stirring method, wherein a moving magnetic field is applied to the molten steel inside to stir the molten steel.