KR960007626B1 - Electromagnetic braking apparatus for continuous casting mold - Google Patents

Abstract

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Description

Electromagnetic Breaking Device of Continuous Casting Mold

1 and 2 show an electromagnetic braking apparatus of a conventional continuous casting mold, and FIG. 1 is a partially broken perspective view of the electromagnetic braking apparatus.

2 is a plan view of the electromagnetic braking device with the cooling box and the width changing device omitted for easier understanding.

3 is a plan view showing an electromagnetic braking device according to the present invention.

4 is a cross-sectional view showing an electromagnetic braking device along line IV-IV of FIG.

* Explanation of symbols for main parts of the drawings

1: mold 2: side wall

3: single wall 4: width changing device

5: cooling box 6: support frame

7: core 8: coil

9: Vibration Table 10: Electromagnet

11: cooling water pipe 13: iron core for forming the magnetic path

The present invention relates to an electromagnetic braking device for controlling molten steel flowing down in a mold by applying an electro-static magnetic field to the molten steel injected into the mold from the immersed nozzle in continuous casting of the molten steel. .

The method of controlling the molten steel flowing down in the mold by applying a static electromagnetic field to the molten steel injected into the mold is to accumulate inclusions in the case of continuous casting of a killed steel, particularly a low carbon Al killed steel at high speed. It is effective in preventing excessive entrapment, curling of powders and bubbles.

The electromagnetic braking device used in this method is disclosed in Japanese Patent Publication Nos. 90-20349 and 90-284750, and generally has a structure shown in FIGS. 1 and 2. The mold 1 having a spherical cross section has a wide side wall 2 and a narrow end wall 3. The electromagnet 10 is disposed along each side wall 2 and has a core 7 and a coil 8 wound around the core 7. A magnetic path forming iron core 13 is connected to an end of the core 7, and the magnetic path forming iron core 13 extends so as to surround the mold 1 so that the side wall of the mold 1 Construct an electromagnet device that applies a static electromagnetic field in the direction of crossing 2). The electromagnet device is mounted on a support frame 6 arranged on the vibration table 9. The keeper frame 6 further supports a width change device 4 for changing the width of the mold by moving the cooling box 5 for cooling the mold 1 and the end wall 3 of the mold. The iron core 13 for shaping has a reduced thickness at the interference portion with these components in order to avoid interference with the width changing device 4 and the support frame 6. Furthermore, in order to avoid interference with the cooling water pipe 11 connected to the cooling box, the corner portion of the iron core 13 for forming the path is cut. In addition, in order to extend the magnetic core forming iron core 13 to surround the mold and the electromagnet, the cooling box 5 is provided with an opening through which the magnetic core forming iron core 13 penetrates.

The electromagnet device should reduce the magnetoresistance of the magnetic core to form the magnetic field to effectively generate the electrostatic field. For this purpose, it is preferable that the iron core for forming the magnetic path has a large cross-sectional area. However, the magnetic braking core of the conventional electromagnetic braking device has a reduced cross-sectional area in order to avoid interference with other components such as support frames, width changing devices, cooling water pipes, etc. No magnetic flux density of about 2000-5000 gauss can be generated at this location. Here, the reason for limiting the magnetic flux density to 2000-5000 gauss to effectively generate the electrostatic field is as follows.

The stronger the magnetic field, the more effectively the molten metal flow discharged from the injection nozzle can be broken and the effect of the inclusions and bubbles floating off the molten metal to separate and improve the quality of the cast. In practice, however, the flotation and separation effects of inclusions and bubbles are saturated when the magnetic flux density exceeds 5000 gauss, and even when a magnetic flux density of 5000 gauss or more is applied, a significant effect of improving the slab cannot be obtained. For this reason (1) large bubbles and inclusions causing product defects can be separated from the molten metal at magnetic flux densities of up to 5000 gauss. (2) Small inclusions usually do not cause product defects and have a small buoyancy, so they are not suspended simply by applying braking to molten metals. On the other hand, if the magnetic flux density is 2000 Gauss or less, the braking effect is small and the large inclusions and the bubbles are not sufficiently floating, so that the effect of improving the slab is small. therefore. The magnetic flux density actually used ranges from 2000 to 5000 gauss.

In addition, when an electromagnetic device capable of generating the magnetic flux density by using a magnetic core having a portion having a reduced cross-sectional area is installed, the weight of the magnetic core is increased, so that the size of the supporting frame also increases. do. In addition, motors for cranes and vibrators in connection with vibrators and continuous casting molds should have increased capabilities. Moreover, another problem arises that the flow of the cooling medium in the cooling box is disturbed because the iron core for forming the large ruler extends through the cooling box.

Accordingly, it is an object of the present invention to provide a continuous casting mold electromagnetic braking device capable of generating a magnetic flux density of about 2000-5000 gauss at the center of the mold without increasing the weight of the continuous casting mold.

An electromagnetic braking device of a continuous casting mold according to the present invention includes a mold having a spherical cross section having a large side wall and a small short wall; An electromagnet composed of a core disposed in connection with the sidewall of the mold and a coil wound around the core and applying a magnetic field in a direction crossing the sidewall of the mold; It consists of a width changing means for changing the width of the mold and a cooling box for cooling the mold, extending to enclose the mold and the electromagnet and connected to the core of the electromagnet to form the path of the electromagnet.

The core may be integrally connected to the support frame or may be detachably connected.

The support frame is preferably made of ferromagnetic material. In addition, the support frame preferably has a cross-sectional area sufficient to generate a magnetic flux density of about 2000-5000 gauss at the center of the mold.

The coil is wound around the core over the gap between the side wall and the support frame.

Since the support frame supporting the width changing means also serves as an iron core for forming magnetic paths of the electromagnet, the conventional iron core for forming magnetic paths is unnecessary. As a result, the spatial constraints are reduced, so that the weight of the continuous casting mold is not significant, the cross-sectional area of the support frame can be increased, and the size of the electromagnet can be increased, so that the magnetic flux density of 2000-5000 gauss at the center of the mold can be increased. May be generated.

In addition, the capacity of the vibrator and the crane can be reduced. Moreover, the flow of the cooling medium in the cooling box is not disturbed.

An electromagnetic braking device according to the present invention will be described with reference to FIG. 3 and FIG.

The spherical cross-section mold 1 includes a wide side wall 2 and a narrow end wall 3. The electromagnet 10 is arranged in connection with the side wall 2 and has a core 7 and a coil 8 wrapped around the core 7. The support frame 6 is arranged on the vibration table 9 and moves the cooling box 5 for cooling the mold 1 and the end wall 3 of the mold to change the width of the mold 4. I support it. The end of the core 7 is integrally or detachably connected to the support frame, and the coil 8 is also wound around the core 7 over the gap between the side wall 2 and the support frame 6. In addition, the support frame 6 extends to surround the mold 1 and the electromagnet 10, and is made of ferromagnetic material. The support frame 6 has a cross-sectional area sufficient to generate a magnetic flux density of about 2000-5000 gauss at the center of the mold.

In the above structure, since the magnetic core forming core is not installed and the support frame 6 can also be a magnetic core for forming the magnetic path, the space occupied by the magnetic core for forming the magnetic path can be reduced by that, so that the continuous casting including the electromagnet is performed. The mold is reduced in weight. therefore. The capacity of the electromagnet 10 can be increased and, accordingly, the braking function performed by this electromagnet can be increased, and the flow of the molten steel can be controlled arbitrarily.

Claims (5)

A spherical cross-section mold 1 having a large side wall 2 and a small short wall 3, a core 7 arranged in connection with the side wall 2 of the mold and a coil wound around the core ( And an electromagnet 10 for applying a magnetic field in a direction crossing the sidewall of the mold, a width changing means 4 for changing the width of the mold, and a cooling box 5 for cooling the mold. A continuous casting mold made of a support frame (6) in an electromagnetic braking device, wherein the support frame (6) extends to surround the mold (1) and the electromagnet (10) and is connected to a core of the electromagnet to An electromagnetic braking device of a continuous casting mold, characterized in that it forms a magnetic path and said support frame is made of ferromagnetic material. 2. An electromagnetic braking device according to claim 1, wherein the core (7) is a continuous casting mold integrally connected with the support frame (6). The method of claim 1. The core (7) is an electromagnetic braking device of a continuous casting mold detachably connected to the support frame (6). The electromagnetic braking device according to claim 1, wherein the support frame (6) has a cross-sectional area sufficient to generate a magnetic flux density of 2000-5000 gauss at the center of the mold (1). 2. The apparatus of claim 1, wherein the coil (8) is wound around the core (7) over the entire gap between the side wall (2) and the support frame (6).