CN201211558Y - An electromagnetic braking device for controlling the flow of molten metal in a continuous casting mold - Google Patents

Abstract

An electromagnetic braking device for controlling the flow of molten metal in a continuous casting mold. The device is composed of a magnetic core, an excitation coil and a magnetic pole half-surrounding the side wall of the mold. In terms of height, it simultaneously covers the surface area of the molten metal near the narrow surface of the mold and the impact point area of the outlet flow. By applying current to the excitation coil, a static magnetic field is generated between the two pairs of magnetic poles, and the mold is simultaneously controlled by this static magnetic field. The inner metal liquid flows on the surface of the metal liquid near the narrow surface of the crystallizer and the flow in the impact point area of the outlet flow. The utility model has the advantages: it can simultaneously effectively suppress the slag roll on the surface of the molten metal near the narrow surface of the crystallizer and the impact depth of the molten metal flowing out of the nozzle, and promote the floating and removal of heterogeneous substances such as inclusions and air bubbles at the front of the metal solidification shell, and at the same time It also weakens the degree of influence on the electromagnetic braking effect when the nozzle immersion depth and nozzle outlet angle change, and the form is simple, the structure is small, and the volume and weight are greatly reduced compared with the full-width first-stage and full-width two-stage electromagnetic brake devices. consumption.

Description

An electromagnetic braking device for controlling the flow of molten metal in a continuous casting mold

technical field

The utility model belongs to the technical field of continuous casting, in particular to an electromagnetic braking device for controlling the flow of molten metal in a continuous casting crystallizer.

Background technique

In the usual continuous casting process of molten metal, the molten metal enters the mold through the nozzle, and the molten metal flowing out of the nozzle has a certain impact velocity, on the one hand, it causes the disturbance of the surface of the molten metal in the mold, and it is easy to displace the surface of the molten metal The slag liquid is brought into the molten metal to pollute the molten steel, especially in the area near the narrow surface of the mold. On the other hand, it causes an impact on the narrow surface of the crystallizer, which makes the metal solidification shell at this place thinner, and at the same time makes the inclusions, bubbles and other heterogeneous substances in the molten metal immerse into the deeper part of the mold, making it difficult to float up and It is captured by the front edge of the metal solidification shell, which affects the cleanliness of the metal billet and causes defects. In order to solve this kind of problem, an electromagnetic brake composed of iron core, magnetic pole and excitation coil is usually applied to the mold to form a static magnetic field in the mold, so that the flowing molten metal is subjected to the flow of molten metal when passing through the static magnetic field. The electromagnetic force in the opposite direction is used to restrain the flow of molten metal in the mold.

In the prior art, electromagnetic brakes in the form of a static magnetic field mainly include a regional electromagnetic brake device, a full-width one-stage electromagnetic brake device, and a full-width two-stage electromagnetic brake (also called FC-Mold). The structural feature of the regional electromagnetic braking device is that two pairs of independent block magnetic poles are arranged in the nozzle outlet area on both sides of the submerged nozzle of the crystallizer in the opposite direction of the magnetic poles. Excitation coils are respectively wound on the two magnetic poles on one side of the wide surface of the crystallizer, and the two magnetic poles are connected together through the magnetic core. This electromagnetic braking device suppresses the flow of molten metal flowing out of the submerged nozzle through the generated regional stable magnetic field. However, due to the limited area of action, the flow state of the entire mold cannot be effectively controlled, the braking effect is low, and it is easy to cause other defects such as channels. The full-width one-stage electromagnetic braking device is composed of a closed magnetic core surrounding the mold and a pair of strip-shaped magnetic poles wound around the excitation coil and covering the entire width of the mold. The magnetic poles are arranged at the lower part of the submerged nozzle. The characteristic is that the size and weight of the magnetic core and the magnetic pole are relatively large. The electromagnetic braking device can brake the flow of molten metal in the entire width direction in the crystallizer, and effectively suppress the impact depth of the molten metal flowing out of the nozzle. However, it is easy to cause upward backflow of the molten metal, especially when the distance between the magnetic pole position and the nozzle and the outlet flow angle of the nozzle do not match, it is easy to cause fluctuations on the surface of the molten metal in the mold, and aggravate the slag entrainment in the narrow area of the mold. At present, the full-width one-stage electromagnetic braking device is mainly used for thin slab continuous casting steel casting. Due to the high casting speed of thin slab continuous casting, the fluctuation of the molten metal surface in the narrow area of the crystallizer is aggravated, which affects the braking effect and easily causes surface slag entrainment. . Moreover, for large slab continuous steel casting, due to the large width of the slab, the magnetic core, coil and magnetic pole of the electromagnetic brake increase accordingly, and the volume of the device is relatively large. The full-width two-stage electromagnetic brake device is composed of two pairs of strip-shaped magnetic poles covering the entire width of the mold. One magnetic pole is located at the lower part of the submerged nozzle, and the other is located at the surface area of the molten metal in the mold, generating a stable and constant magnetic field with opposite magnetic flux. . On the wide side of the crystallizer, the upper and lower full-width magnetic poles are connected to form a semi-closed magnetic core circuit. The electromagnetic braking device can simultaneously reduce the impact depth of molten metal flowing out of the nozzle in the crystallizer and the flow on the surface of the molten metal, and has better braking effect. The device is mainly used for continuous casting of large slabs to suppress the flow rate of molten steel on the surface of the molten metal and the downward flow rate of the descending stream in the crystallizer. Due to the application of two magnetic fields, the reverse flow caused by the controlled flow of the lower part is suppressed, which has a more effective and reasonable flow state of molten steel than the full-width single-strip electromagnetic brake. However, due to the addition of a section of magnetic poles and coils to this electromagnetic brake device, the volume and weight of the device are relatively large.

Utility model content

In view of the above characteristics of the existing electromagnetic braking device, especially the full-width one-stage electromagnetic braking device for thin slab continuous casting, it cannot effectively suppress the fluctuation of the molten metal surface in the area near the narrow surface of the mold, and it is easy to cause surface slag entrainment, and large The full-width two-stage electromagnetic braking device for slab continuous casting has the characteristics of large volume and weight. The utility model provides an electromagnetic braking device for controlling the flow of molten metal in a continuous casting crystallizer.

Based on the characteristics that the main affected area of the molten metal flowing out of the nozzle is located in the surface area of the molten metal near the narrow surface of the crystallizer and the impact area of the narrow surface of the crystallizer outflow from the nozzle, the utility model deflects the magnetic pole to the narrow surface area of the mold Arrangement, with a pair of magnetic poles simultaneously covering the surface area of the molten metal near the narrow surface of the mold and the impact area of the nozzle outlet, and the two pairs of magnetic poles opposite to each other on both sides of the wide surface of the mold are connected by a magnetic core that half surrounds the narrow surface of the mold together. The technical scheme adopted is as follows:

The electromagnetic braking device of the utility model is composed of two and a half magnetic cores surrounding the side walls of the crystallizer, excitation coils and magnetic poles. The magnetic poles are arranged in the vicinity of the narrow face of the bias mold. In the height direction, the top of the magnetic pole is located within the range from 50mm up to 800mm down from the molten steel surface of the mold; The surface area of the molten metal near the narrow surface of the mold and the impact point area of the nozzle outlet are covered simultaneously. By applying current to the field coil, a static magnetic field is generated between the two pairs of magnetic poles. Through the static magnetic field generated between the pair of magnetic poles, the flow of the molten metal in the mold on the surface of the molten metal near the narrow surface of the mold and the flow of the nozzle outflow impact point area are simultaneously controlled.

The excitation coils of the electromagnetic braking device can be arranged in two ways: one way is that two sets of excitation coils are respectively arranged in the center of the magnetic core and on the narrow side of the crystallizer. Another way is that the four sets of exciting coils are respectively arranged in the magnetic pole area of the magnetic core, and are respectively located on one side of the wide surface of the crystallizer.

Two connection methods can be used between the magnetic core and the magnetic pole of the electromagnetic braking device. One way is gap active connection. This method enables the magnetic pole to move horizontally in the direction of the wide surface of the mold, and freely adjusts the distance between it and the nozzle, so that the magnetic pole can still be arranged near the narrow surface of the mold when the width of the mold is adjusted. Another way is the overall connection method, that is, the magnetic core and the magnetic pole are integrated. This method adjusts the distance between it and the nozzle by moving the whole horizontally in the direction of the width of the crystallizer, so that when the width of the mold is adjusted The magnetic poles can still be arranged close to the narrow faces of the mould.

The excitation coil of the electromagnetic braking device can be a water-cooled copper coil or a superconducting material coil. When a water-cooled copper coil is used, a static magnetic field with a magnetic induction intensity of 0.1T-1.2T can be generated; when a superconducting material coil is used, a magnetic induction intensity of 0.1T～5.0T static magnetic field.

The electromagnetic braking device of the utility model, through a pair of magnetic poles simultaneously covering the surface area of the molten metal near the narrow surface of the crystallizer and the impact area of the outlet flow, overcomes the fact that the electromagnetic braking device of the whole width cannot effectively restrain the narrow surface area of the mold Fluctuations on the surface of the molten metal can easily cause the disadvantages of slag on the surface. At the same time, it also weakens the degree of influence on the electromagnetic braking effect when the nozzle immersion depth and nozzle outlet angle change, and can effectively suppress the molten metal surface on the narrow side of the mold at the same time. The impact depth of slag entrainment and liquid metal flowing out of the nozzle promotes the floating and removal of heterogeneous substances such as inclusions and air bubbles at the front of the metal solidification shell. At the same time, due to the use of two semi-annular magnet structures, the form is simple, the structure is small, and the volume and weight are greatly reduced compared with the full-width one-stage and full-width two-stage electromagnetic brake devices, which can save energy and reduce consumption.

Description of drawings:

Fig. 1 is a structural schematic diagram of the electromagnetic brake device of the present invention, wherein the exciting coils are respectively arranged at the central part of the magnetic core and located at the narrow side of the crystallizer;

Fig. 2 is a structural schematic diagram of another arrangement of excitation coils of the electromagnetic braking device of the present invention, that is, four sets of excitation coils are respectively arranged in the magnetic pole area of the magnetic core, and are respectively located on the wide side of the crystallizer. The connection between the magnetic pole and the magnetic core is an integral connection;

Fig. 3 is a schematic diagram of another way of connecting the magnetic pole and the magnetic core of the electromagnetic braking device of the present invention, that is, the connection mode of the magnetic pole and the magnetic core is a gap type movable connection;

Fig. 4 is a schematic diagram of the implementation effect of the electromagnetic braking device of the present utility model;

In the figure: 1 crystallizer, 2 magnetic core, 3 excitation coil, 4 magnetic pole, 5 molten metal near the narrow surface of the mold, 6 nozzle.

Detailed ways

example 1:

As shown in Figure 1, the electromagnetic braking device of the present invention is composed of a magnetic core 2, an excitation coil 3, and a magnetic pole 4 that are half-surrounded on the side wall of the crystallizer 1. 4 Cover the surface area of the molten metal 5 near the narrow surface of the crystallizer 1 and the impact point area of the outlet 6 at the same time in height, and apply a current to the excitation coil 3 to generate a static magnetic field between the two pairs of magnetic poles 4. This embodiment The two sets of excitation coils 3 are respectively arranged at the center of the magnetic core 2, on the side of the narrow side of the crystallizer.

For a mold with a cross-sectional size of 1400×230mm, a nozzle immersion depth of 150mm, and a nozzle side hole inclination angle of -15 degrees, the magnetic pole of the electromagnetic brake should be placed near the narrow surface of the continuous casting mold. In the height direction, the top of the magnetic pole is located within the range from 50mm up to 300mm down from the molten steel surface of the mold; in the width direction, the magnetic pole is located within the range of 150mm from the side wall of the mold. That is, the cross-sectional size of the magnetic pole is 150×300mm, so that the magnetic pole simultaneously covers the surface area of the molten metal near the narrow surface of the mold and the impact point area of the outlet flow. The magnetic core and the magnetic poles are integrally connected. When the excitation coil adopts a water-cooled copper coil, after applying a current to generate a 0.3T static magnetic field, for the continuous casting condition with a casting speed of 2.0m/min, the flow velocity of the molten steel surface area and the flow velocity of the nozzle outlet impact area can be significantly reduced. As shown in Figure 4.

Example 2:

According to the magnetic pole, magnetic core and excitation coil layout scheme of the electromagnetic brake shown in Figure 3, the connection mode of the magnetic pole and the magnetic core is connected. For a mold with a cross-sectional size of 1400×230mm, a nozzle immersion depth of 150mm, and a nozzle side hole inclination angle of -15 degrees, the electromagnetic brake magnetic pole is placed near the narrow surface of the continuous casting mold. In the height direction, the top of the magnetic pole is located within the range from 50mm up to 500mm down from the molten steel surface of the mold; in the width direction, the magnetic pole is located within the range of 180mm inward from the side wall of the mold. That is, the cross-sectional size of the magnetic pole is 180×500mm, so that the magnetic pole simultaneously covers the surface area of the molten metal near the narrow surface of the mold and the impact point area of the outlet flow. When the width of the narrow side of the mold is adjusted during the continuous casting process, and the width of the slab is reduced from 1400mm to 1100mm, the magnetic pole of the electromagnetic brake can move 150mm to the center of the mold, so that the magnetic pole still controls the liquid steel surface near the narrow side of the mold. The flow of molten steel near the impact point of the nozzle outlet. When the excitation coil adopts a superconducting material coil, after applying a current to generate a static magnetic field of 1.5T, it can also significantly reduce the flow velocity of the molten steel surface area and the impact area of the nozzle outlet for the continuous casting condition of the casting speed of 5.0m/min. flow rate.

Example 3:

The structure of the device is the same as Example 1, the difference is that for a mold with a cross-sectional size of 1400×230mm, a nozzle immersion depth of 150mm, and a nozzle side hole inclination angle of -15 degrees, the magnetic pole of the electromagnetic brake is placed near the narrow surface of the continuous casting mold. In the height direction, the top of the magnetic pole is located within the range from 50mm up to 800mm down from the molten steel surface of the mold; in the width direction, the magnetic pole is located within the range of 400mm from the side wall of the mold. That is, the cross-sectional size of the magnetic pole is 400×800mm, so that the magnetic pole simultaneously covers the surface area of the molten metal near the narrow surface of the mold and the impact point area of the outlet flow. The magnetic core and the magnetic poles are integrally connected.

Claims (4)

1, a kind of mobile electro-magnetic braking device of continuous cast crystallizer inner metal liquid of controlling, it is characterized in that this device is around in the magnetic core of crystallizer sidewall by semi-ring, magnet exciting coil and magnetic pole are formed, magnetic pole is arranged in the leptoprosopy zone of deflection crystallizer, magnetic pole in height covers the shock point zone that near the crystallizer leptoprosopy molten metal surf zone and the mouth of a river go out stream simultaneously, by magnet exciting coil is applied electric current, between two pairs of magnetic poles, produce magnetostatic field, go out to flow flowing of shock point zone with the mouth of a river by near the surface of this magnetostatic field while crystallization control device inner metal liquid molten metal crystallizer leptoprosopy is mobile.

2, the mobile electro-magnetic braking device of control continuous cast crystallizer inner metal liquid as claimed in claim 1, it is characterized in that described magnet exciting coil be arranged as two groups of magnet exciting coils be arranged in respectively magnetic core the centre, be positioned at leptoprosopy one side of crystallizer, or be the pole regions that four groups of magnet exciting coils are arranged in magnetic core respectively, lay respectively at wide one side of crystallizer.

3, the mobile electro-magnetic braking device of control continuous cast crystallizer inner metal liquid as claimed in claim 1, the clearance-type that is connected to that it is characterized in that described magnetic core and magnetic pole flexibly connects, and magnetic pole moves in magnetic core, regulates position of magnetic pole, or be whole the connection, magnetic core and magnetic pole are as a whole.

4, the mobile electro-magnetic braking device of control continuous cast crystallizer inner metal liquid as claimed in claim 1, it is characterized in that described magnet exciting coil is the water-cooled copper coil, producing magnetic induction intensity is the magnetostatic field of 0.1T～1.2T, or be the superconductor coil, producing magnetic induction intensity is the magnetostatic field of 0.1T～5.0T.

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