CN115194107B - Multi-stage independent adjustable composite magnetic field device and method for controlling metal liquid flow - Google Patents

Abstract

The invention belongs to the technical field of continuous casting, and particularly relates to a multi-stage independently adjustable composite magnetic field device and method for controlling molten metal to flow. The multi-stage independently adjustable composite magnetic field device can meet the requirement of metal liquid flow control in the area between the surface of the molten metal and the jet impact point of the narrow surface of the crystallizer in the height direction of the crystallizer, and can reduce the influence of technological parameter changes such as the blank drawing speed, the jet angle of the molten metal, the depth of a submerged nozzle and the like on the metal liquid flow control effect. Comprises three parts: a vertical electromagnetic stirring device, a horizontal electromagnetic stirring device and a jet type electromagnetic braking device; the three parts independently adjust the current intensity according to different casting conditions, and the flow of the molten metal in the slab continuous casting crystallizer is controlled in a partitioning way.

Description

Multi-segment independently adjustable composite magnetic field device and method for controlling molten metal flow

technical field

The invention belongs to the technical field of continuous casting, and in particular relates to a multi-stage independently adjustable composite magnetic field device and method for controlling the flow of molten metal.

Background technique

As the reactor in the last link of the continuous casting production process, the mold has a direct impact on the final quality of the cast slab. However, as the production capacity of the continuous casting machine increases gradually, the casting speed increases continuously. After the molten metal flows into the mold through the submerged nozzle, it impacts towards the narrow surface of the mold at a relatively high speed. Due to the increase of the casting speed, the turbulent flow of the molten metal at the outlet of the nozzle is severe, which leads to the aggravation of the meniscus fluctuation and the irregular flow of the molten metal in the mold, which in turn causes the backflow of the molten metal in the mold and the deviation of the outlet flow of the nozzle. In addition, the flow of molten metal out of the nozzle under the high turbulence state also causes the solidified slab shell formed near the narrow surface of the mold to be thinned and pierced, which in turn causes uneven thickness distribution of the solidified slab shell, inclusions under the skin of the continuous casting slab, and casting slab Negative effects such as surface defects.

In order to solve such problems, technicians install electromagnetic braking devices or electromagnetic stirring devices on both sides of the wide surface of the continuous casting mold to form an electromagnetic field in the mold, and the electromagnetic force generated by the electromagnetic field can inhibit or strengthen the flow of molten metal, thereby Improve the flow state of the metal liquid in the crystallizer, prevent surface slag entrainment, and promote surface slag melting.

In recent years, a variety of electromagnetic braking devices have emerged in China. For example, the Chinese patent No. 200810011104.7 discloses a vertical electromagnetic braking device. Wide surface area, so that the stable magnetic field generated by the vertical strip magnetic pole can cover the impact area of the outlet flow and the area near the meniscus, thereby inhibiting the impact of the molten steel from the nozzle on the narrow surface of the mold and reducing the backflow impact intensity. Stabilize the free liquid surface flow of the crystallizer, and reduce the probability of defects such as slag entrainment and slag inclusion. However, when the width of the mold is large, the coverage width of the steady magnetic field generated by the vertical strip magnetic pole of this electromagnetic braking device in the width direction of the mold is limited, resulting in the weakening of the magnetic field effect at the central area of the mold width , cannot effectively control the impact depth of the reflowed molten steel under the central area of the mold, and is not conducive to the floating and removal of heterogeneous substances such as inclusions and bubbles.

The Chinese patent No. 201610580291.5 also discloses a vertical electromagnetic brake device, which adds two pairs of vertical strip magnetic poles to the wide surface area near the narrow surface of the crystallizer on the basis of the full-width one-stage electromagnetic brake device. The vertical strip magnetic poles are embedded and connected with the horizontal magnetic poles. With the help of the excitation coil and the power control system of the full-width electromagnetic brake device, the vertical stable magnetic field generated by it can cover the jet impact area, the meniscus area and the crystallizer. The reflow area is used to make up for the defect of insufficient braking of the area-type and full-width one-stage electromagnetic braking device on the reflow area on the crystallizer. At the same time, the horizontal stable magnetic field generated by the horizontal magnetic pole is close to the electromagnetic braking effect of the full-width first-stage and full-width second-stage electromagnetic brake devices, which can effectively control the flow of molten steel in the reflow area under the mold. However, the connection mode between the vertical strip magnetic poles and the horizontal magnetic poles of this electromagnetic braking device is an embedded connection, and the magnetic field strength generated between the vertical strip magnetic poles is limited by the magnetic field strength of the horizontal magnetic poles. When the horizontal magnetic poles When the generated magnetic field strength is weak, the magnetic field strength generated between the vertical strip magnetic poles decays significantly along the height direction of the mold, so it is not conducive to improving the braking effect of the vertical strip magnetic poles.

The Chinese patent No. 201910032306.8 discloses an independently adjustable combined electromagnetic braking device, which arranges two pairs of vertical strip magnetic poles and a pair of horizontal magnetic poles on both sides of the wide surface of the crystallizer. The horizontal magnetic poles are separately configured by the horizontal excitation coil. The vertical strip magnetic poles are separately configured by the vertical excitation coils, the horizontal magnetic poles and the vertical strip magnetic poles are not connected to each other, and the magnetic field strength generated between the vertical strip magnetic poles is not limited to the magnetic field strength of the horizontal magnetic poles, which can be determined according to the crystallization The current intensity is independently adjusted according to the actual flow of molten metal in the device. However, the horizontal magnetic poles of this type of electromagnetic braking device cannot be freely adjusted in the height direction of the mold, resulting in limited coverage of the stable magnetic field generated by the horizontal magnetic poles in the height direction of the mold. When the process parameters such as the outflow angle of the submerged nozzle and the impact depth change, the horizontal magnetic pole cannot maintain a good matching state with the process parameters, which will significantly reduce the braking effect of the horizontal magnetic pole.

Subsequently, electromagnetic devices with the combined effect of DC magnetic field and AC magnetic field have appeared in China. For example, the Chinese patent No. 201080019323.5 discloses a composite electromagnetic device, which is respectively installed on the wide surface area of the crystallizer on the upper and lower sides of the submerged nozzle. The electromagnetic stirring device and the full-width electromagnetic braking device are arranged. Under the joint action of the upper end electromagnetic stirring device and the lower end full-width electromagnetic braking device, this kind of composite electromagnetic device can realize partitioned control of the molten metal in different areas in the crystallizer. Flow, the AC magnetic field generated by the upper electromagnetic stirring device can strengthen the flow of molten metal in the upper area of the mold and maintain the activity of the molten metal surface, and the DC magnetic field generated by the full-width electromagnetic brake device at the lower end can reduce the penetration of molten metal on the molten pool in the lower part of the mold Penetration depth, maintaining the floating rate of inclusions, bubbles and other heterogeneous substances. However, this kind of composite electromagnetic device is connected by a yoke between the electromagnetic stirring device arranged on the upper and lower sides of the submerged nozzle and the full-width electromagnetic braking device. The alternating magnetic field generated by the electromagnetic stirring device and the full-width electromagnetic braking device The generated DC magnetic fields interfere with each other, which will significantly reduce the current control effect of the composite magnetic field at the yoke connection.

The Chinese patent No. 201710107017.0 also discloses a composite electromagnetic device. Under the joint action of the electromagnetic stirring device and the regional electromagnetic brake device, the strip-shaped traveling magnetic field generated by the upper electromagnetic stirrer and the lower regional electromagnetic device The DC stable magnetic field generated by the electromagnetic brake can control the flow of molten metal in different regions of the mold in a partitioned manner. The upper electromagnetic stirring device and the lower regional electromagnetic braking device of this composite electromagnetic device have independent power supply systems, which can independently control their respective electromagnetic strengths according to the actual flow of molten metal in the crystallizer. However, the strip-shaped traveling-wave magnetic field generated by the upper electromagnetic stirring device and the DC steady magnetic field generated by the lower regional electromagnetic braking device have limited coverage in the height direction of the mold, which will reduce the flow rate between the upper and lower recirculation areas of the mold and the jet flow. The flow control effect of the metal liquid in the impact zone leads to insufficient mixing of the solute and temperature inside the slab, which is not conducive to the improvement of the quality of the slab center.

Contents of the invention

The present invention is aimed at the defects of the prior art, and it aims at the problems of the existing electromagnetic devices, especially the problem that the regional magnetic poles of the regional electromagnetic braking device cannot effectively control the flow of molten metal in the lower recirculation zone in the crystallizer. The problem that the horizontal strip magnetic poles of the full-width two-stage electromagnetic brake device cannot be adjusted freely in the direction of the mold height, and the upper horizontal bar magnetic pole of the full-width two-stage electromagnetic brake device causes the problem that the surface flow rate of the molten metal is too low , the problem that the vertical bar-shaped magnetic poles arranged separately by the vertical electromagnetic braking device have a weak braking effect on the flow of molten metal in the central area of the mold, and the electromagnetic stirring device arranged separately from the composite electromagnetic device and the regional electromagnetic braking device are relatively weak. In order to solve the problem that the braking effect of molten metal flow in the upper and lower reflow areas of the crystallizer is relatively weak, the present invention proposes a multi-segment independently adjustable composite magnetic field device and method for controlling the flow of molten metal.

To achieve the above object, the present invention adopts the following technical solutions:

The multi-stage independently adjustable composite magnetic field device that controls the flow of molten metal includes three parts: vertical electromagnetic stirring device, horizontal electromagnetic stirring device, and jet electromagnetic braking device; the three parts independently adjust their respective current strengths according to different casting conditions. Partitioned control of molten metal flow in the slab continuous casting mold.

Further, the vertical electromagnetic stirring device includes a vertical stirring magnetic pole, a stirring iron core and a stirring coil, the stirring coil is set outside the stirring iron core, and the outer end of the stirring iron core is equipped with a stirring magnetic pole, and the three form an integrated structure ; two groups of them are symmetrically arranged on the wide or narrow surface of the crystallizer; the traveling wave magnetic field generated by the vertical electromagnetic stirring device can drive the molten metal in the jet impact area to the meniscus area for relative motion (wherein the jet impact area It is the area where the metal jet flows out from the side hole of the submerged nozzle. The meniscus area is the area where the molten metal at the upper end of the crystallizer is in contact with the wall of the mold and bends. The upper backflow area is where the metal jet flowing out of the side hole of the submerged nozzle impacts to the crystal The area where upward reflux occurs behind the narrow side wall of the crystallizer); when the vertical electromagnetic stirring device is installed on the wide surface of the crystallizer, three stirring iron cores are arranged inside each vertical stirring magnetic pole; the vertical electromagnetic stirring device is installed on the crystallizer For narrow surfaces, six stirring iron cores are arranged inside each vertical stirring pole.

Further, the horizontal electromagnetic stirring device includes a horizontal stirring magnetic pole, a stirring iron core and a stirring coil, the stirring coil is set outside the stirring iron core, and the outer end of the stirring iron core is equipped with a stirring magnetic pole, and the three form an integrated structure; and Three stirring iron cores are arranged on the inside of each horizontal stirring magnetic pole, and each stirring iron core is equipped with a stirring coil; the horizontal electromagnetic stirring devices are arranged in groups of two and symmetrically arranged on the wide surface of the crystallizer and on both sides of the molten metal; The traveling wave magnetic field generated by the horizontal electromagnetic stirring device on both sides of the wide surface of the crystallizer can drive the molten metal in the magnetic field area to move relatively horizontally.

Further, the jet-type electromagnetic brake device includes an integrated structure composed of rectangular magnetic poles, yokes and excitation coils, and the jet-type electromagnetic brake devices are arranged in groups of two by two, symmetrically arranged on the wide surface of the crystallizer and the outlet of the submerged nozzle. On both sides of the molten metal flow area; the jet-type electromagnetic braking device adopts the form of a steady DC magnetic field, and the jet-type electromagnetic braking device excites on both sides of the wide surface of the mold to generate a steady direct current perpendicular to the wide surface of the slab mold The magnetic field can directly drive the molten metal in the jet flow area at the exit of the submerged nozzle to move relative to each other; the rectangular magnetic poles correspond to the magnetic yoke, and excitation coils are arranged on the outside of the rectangular magnetic poles, and the outer surface of the excitation coil is connected to the inner surface of the magnetic yoke and the crystallizer. External surface clearance fit.

Furthermore, the upper surface of the vertical stirring magnetic pole of the vertical electromagnetic stirring device is 5-150 mm higher than the surface of the molten metal, and the thickness of the vertical stirring magnetic pole along the width direction of the crystallizer is 50-400 mm. The thickness of the magnetic pole along the height direction of the crystallizer is 150-1000mm, the electromagnetic stirring frequency of the vertical stirring magnetic pole is 0.01-10Hz, and the AC power supply of the stirring coil is 0.01-6000A;

When the vertical electromagnetic stirring device is located on the wide surface of the crystallizer, the vertical stirring magnetic pole can rotate freely in the height direction of the crystallizer, and the rotation angle is between -60°～60°. The outer surface of the vertical stirring magnetic pole is in contact with the crystal The distance L1 between the narrow surfaces of the crystallizer is 0-200 mm, and the distance L2 between the inner surfaces of the vertical stirring magnetic poles on the same side of the wide surface of the crystallizer is 500-1500 mm.

When the vertical electromagnetic stirring device is located on the narrow side of the mold, the inner surface of the stirring iron core of the vertical electromagnetic stirring device is 0-200mm away from the narrow side of the mold; The minimum distance ratio between the surface and the upper surface of the rectangular magnetic pole of the jet-type electromagnetic braking device is greater than 0.5, and the minimum distance between the lower surface of the vertical stirring magnetic pole and the upper surface of the rectangular magnetic pole is greater than 50mm.

Furthermore, the upper surface of the horizontal stirring magnetic pole of the horizontal electromagnetic stirring device is 5-150mm higher than the surface of the molten metal, the thickness of the horizontal stirring magnetic pole along the width direction of the crystallizer is 50-500mm, and the horizontal stirring magnetic pole is 50-500mm along the width direction of the mold. The thickness of the magnetic pole in the height direction is 50-500mm, the distance L3 between the outer surface of the horizontal stirring magnetic pole and the narrow surface of the crystallizer is 150-400mm, the electromagnetic stirring frequency of the horizontal stirring magnetic pole is 0.01-10Hz, and the AC power supply of the stirring coil is 0.01- 6000A.

Furthermore, the rectangular magnetic poles of the jet-type electromagnetic braking device can freely rotate in the width direction of the crystallizer, and the rotation angle is between -60° and 60°. The minimum distance between them is 50-300mm, the magnetic pole thickness of the rectangular magnetic poles along the mold height direction is 10-1000mm, the magnetic pole thickness of the rectangular magnetic poles along the mold width direction is 50-400mm, and the rectangular magnetic poles are stable The magnetic induction intensity of the constant magnetic field is 0.01-3T.

Further, the vertical electromagnetic stirring device can be freely selected in combination with the horizontal electromagnetic stirring device and the jet electromagnetic braking device in the width direction or height direction of the crystallizer.

Further, when the pulling speed is high, the operation of the vertical type electromagnetic stirring device, the horizontal type electromagnetic stirring device and the jet type electromagnetic braking device decelerates the flow of the molten metal controlled respectively; The operation mode of the device and the horizontal electromagnetic stirring device is opposite to that of high casting speed, and is used to increase the flow rate of the molten metal controlled by each.

A multi-segment independently adjustable composite magnetic field method for controlling the flow of molten metal, including:

Step 1. During the continuous casting process, the molten metal enters the crystallizer through the submerged nozzle, and the molten metal flowing out from the outlet of the submerged nozzle hits the narrow surface of the mold to form an upper backflow and a lower backflow;

Step 2. Connect the three-phase low-frequency power supply to the vertical type electromagnetic stirring device and the horizontal type electromagnetic stirring device, and connect the DC power supply to the jet type electromagnetic braking device at the same time to form a vertical traveling wave magnetic field, a horizontal traveling wave magnetic field and Steady and constant DC magnetic field; the vertical traveling wave magnetic field generated by the vertical electromagnetic stirring device can drive the metal liquid in the jet impact area to the meniscus area for relative motion, and at the same time, it can inhibit the bending of the upper backflow metal liquid near the narrow surface of the crystallizer. The impact of the moon surface and the metal liquid surface; the horizontal traveling wave magnetic field generated by the horizontal electromagnetic stirring device can keep the meniscus and the attached slag layer active on the metal liquid surface while driving the metal liquid in the free surface area of the mold to move horizontally At the same time, it can prevent the molten slag from solidifying to form a slag ring when the flow rate of the molten metal on the liquid surface on the crystallizer is too low; the steady DC magnetic field generated by the jet-type electromagnetic brake device drives the molten metal in the jet flow area at the exit of the submerged nozzle. While moving, it can reduce the penetration depth of the downflow molten metal into the molten pool of the mold, and promote the floating and removal of non-metallic inclusions, bubbles and other heterogeneous substances entrained by the molten metal in the central area of the mold.

Compared with the prior art, the present invention has beneficial effects.

1. The multi-stage independently adjustable composite magnetic field device of the present invention is composed of a vertical type electromagnetic stirring device, a horizontal type electromagnetic stirring device and a jet type electromagnetic braking device. Each electromagnetic device is not connected to each other and is independent of each other. The electromagnetic stirring frequency and current intensity of each system are individually adjusted for different casting conditions.

2. The multi-segment independently adjustable composite magnetic field device of the present invention can strengthen the flexible control of the composite electromagnetic device, wherein the vertical traveling wave magnetic field generated by the vertical electromagnetic stirring device can cover the meniscus area, the jet impact area and the crystallizer There are three key areas in the upper backflow area. The horizontal traveling wave magnetic field generated by the horizontal electromagnetic stirring device can cover the surface of the molten metal and the entrance area of the submerged nozzle. The steady DC magnetic field generated by the jet-type electromagnetic brake device can cover the jet flow at the outlet of the submerged nozzle. The flow area and the lower reflow area of the crystallizer, so as to realize the divisional control of the flow of molten metal in the crystallizer.

3. The multi-segment independently adjustable composite magnetic field device of the present invention can meet the flow control requirements of the metal liquid in the area between the surface of the molten metal and the jet impact point on the narrow surface of the mold in the height direction of the mold, and at the same time reduce the casting speed and metal The influence of process parameters such as liquid jet angle and submerged nozzle depth on the effect of metal liquid flow control.

4. The multi-segment independently adjustable composite magnetic field device of the present invention can flexibly adjust the form, position and arrangement angle of the vertical electromagnetic stirring device and the jet electromagnetic braking device according to the flow of molten metal at the outlet of the submerged nozzle, so as to ensure more effective The multi-segment independently adjustable composite magnetic field device can fully play the role of controlling the flow of molten metal in the crystallizer.

5. The vertical traveling wave magnetic field and the steady DC magnetic field generated by the excitation of the multi-segment independently adjustable composite magnetic field device of the present invention can improve the deflection of the jet flow at the exit of the submerged nozzle to both sides of the wide surface of the crystallizer, and the blockage or bias of the submerged nozzle. .

6. The multi-segment independently adjustable composite magnetic field device of the present invention is suitable for different casting speeds of slabs. The horizontal electromagnetic stirring device arranged in the width direction of the mold and the jet type electromagnetic brake device arranged in the direction of the height of the mold The vertical electromagnetic stirring device is used in conjunction with each other. Under the high-speed process conditions, the flow of molten metal at the meniscus on the side of the mold that is easy to induce slag entrainment on the surface of the molten metal is controlled by increasing the current intensity of the vertical stirring magnetic pole. The current intensity of the horizontal stirring magnetic pole and the rectangular magnetic pole can maintain a certain flow rate and heat exchange capacity on the surface of the molten metal, thereby improving the ability of the mold slag to absorb inclusions, so as to obtain a good comprehensive effect of electromagnetic braking.

7. The multi-segment independently adjustable composite magnetic field device of the present invention can avoid the mutual interference of the low-frequency alternating magnetic field generated by the vertical electromagnetic stirring device and the horizontal electromagnetic stirring device and the steady DC magnetic field generated by the jet-type electromagnetic brake device, so as to facilitate The working stability of the multi-segment independently adjustable composite magnetic field device.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the following expressions.

Figure 1 is a three-dimensional schematic diagram of a multi-segment independently adjustable composite magnetic field device in which the vertical electromagnetic stirring device of the present invention is located in the vertical direction of the wide surface of the crystallizer, and the jet-type electromagnetic braking device is located in the direction of -25° angle on the wide surface of the mold.

Figure 2 is a three-dimensional schematic diagram of a multi-segment independently adjustable composite magnetic field device in which the vertical electromagnetic stirring device of the present invention is located in the vertical direction of the narrow surface of the crystallizer, and the jet-type electromagnetic braking device is located in the wide surface of the mold at an angle of -25°.

Fig. 3 is a schematic diagram of the magnetic pole layout of the multi-stage independently adjustable composite magnetic field device of the vertical electromagnetic stirring device of the present invention located in the vertical direction of the wide surface of the crystallizer.

Fig. 4 is a schematic diagram of the magnetic pole layout of the multi-stage independently adjustable composite magnetic field device of the vertical electromagnetic stirring device of the present invention located in the vertical direction of the narrow surface of the crystallizer.

Figure 5 shows that under the multi-segment independently adjustable composite magnetic field device in Figure 1, a current of 800A is applied to the horizontal electromagnetic stirring device, and the stirring frequency is 5Hz; a current of 500A is applied to the vertical electromagnetic stirring device, and the stirring frequency is 5Hz; When the current is 300A, the magnetic field distribution diagram of the center plane of the mold thickness along the height direction of the mold.

Figure 6 shows that under the multi-segment independently adjustable composite magnetic field device in Figure 1, a current of 600A is applied to the horizontal electromagnetic stirring device, and the stirring frequency is 5Hz; a current of 500A is applied to the vertical electromagnetic stirring device, and the stirring frequency is 5Hz; When the current is 300A, the Lorentz force distribution diagram on the horizontal section along the width direction of the mold at a position 65mm below the molten metal surface.

In the figure, 1—submerged nozzle, 2—mold, 3—surface of molten metal, 4—vertical stirring pole, 5—horizontal stirring pole, 6—stirring core, 7—stirring coil, 8—rectangular magnetic pole, 9 – Field coil.

Detailed ways

The multi-segment independently adjustable composite magnetic field device arranges a vertical electromagnetic stirring device in the height direction of the mold, and a horizontal electromagnetic stirring device and a jet electromagnetic braking device in the width direction of the mold, so that the vertical operation generated Wave AC magnetic field, horizontal traveling wave AC magnetic field and steady DC magnetic field can cover the four key areas of meniscus area, jet impact area, mold upper reflow area and lower reflow area, realizing partitioned control of molten metal flow in the mold. The multi-stage independently adjustable composite magnetic field device is less affected by the change of electromagnetic parameters and process parameters. Among them, the vertical electromagnetic stirring device, the horizontal electromagnetic stirring device and the jet electromagnetic braking device are powered independently, and can be independent according to different casting conditions. Adjust the current intensity of each system. The vertical traveling wave AC magnetic field generated by the vertical electromagnetic stirring device can flexibly control the impact of the upper and backflow metal liquid on the meniscus near the narrow surface of the crystallizer, and the horizontal traveling wave AC magnetic field generated by the horizontal electromagnetic stirring device can maintain the meniscus And the activity of the slag layer attached to the metal liquid surface, to avoid the formation of slag rings caused by solidification of molten slag when the flow rate of molten metal on the liquid surface of the mold is too low. The steady DC magnetic field generated by the jet-type electromagnetic braking device can suppress the impact of the metal jet at the exit of the nozzle on the narrow surface of the crystallizer, and at the same time reduce the penetration depth of the downflow metal liquid into the mold pool, avoiding the flow rate of the downflow metal liquid When it is too fast, it will be more difficult for heterogeneous substances such as non-metallic inclusions and bubbles entrained in the molten metal in the central area of the mold to float up.

As shown in Figures 1-6, the specific embodiment: a multi-segment independently adjustable composite magnetic field device and method for controlling the flow of molten metal in the crystallizer 2, adopting a vertical type electromagnetic stirring device, a horizontal type electromagnetic stirring device and a jet type The electromagnetic brake device controls the flow of molten metal in the slab continuous casting mold in a partitioned manner. The vertical stirring magnetic pole 4, the stirring iron core 6 and the stirring coil 7 constitute a vertical electromagnetic stirring device, which is arranged in the recirculation area, the jet impact area and the meniscus area on both sides of the wide or narrow side of the crystallizer 2. The horizontal stirring magnetic pole 5, the stirring iron core 6 and the stirring coil 7 form a horizontal electromagnetic stirring device, which is arranged in the area of the molten metal surface 3 on both sides of the wide surface of the crystallizer 2. The rectangular magnetic pole 8, the magnetic yoke and the excitation coil 9 constitute a jet type electromagnetic braking device, which is arranged in the flow area of the molten metal at the outlet of the submerged nozzle on both sides of the wide surface of the crystallizer 2. The vertical electromagnetic stirring device, the horizontal electromagnetic stirring device and the jet electromagnetic braking device are not connected to each other, and each has an independent power supply system, which can independently adjust the current intensity of each system according to the flow state of the metal liquid in the crystallizer 2 to realize partitioned control The molten metal flows in the crystallizer 2 .

The multi-stage independently adjustable composite magnetic field device includes a vertical electromagnetic stirring device, a horizontal electromagnetic stirring device and two jet electromagnetic braking devices or two vertical electromagnetic stirring devices, a horizontal electromagnetic stirring device and two A jet type electromagnetic braking device.

The vertical electromagnetic stirring device includes two forms. The traveling wave magnetic field generated by the two vertical electromagnetic stirring devices on both sides of the narrow or wide surface of the crystallizer 2 can drive the jet impact area to the meniscus area for the molten metal to move. relative movement.

The first type of vertical electromagnetic stirring device is located on both sides of the wide surface of the crystallizer 2, and is equipped with four vertical stirring magnetic poles 4, and each vertical stirring magnetic pole 4 is equipped with three stirring iron cores 6 inside, each stirring iron core 6 is equipped with a stirring coil 7, and two vertical stirring magnetic poles 4 arranged face to face form a vertical electromagnetic stirring device.

The second type of vertical electromagnetic stirring device is located on both sides of the narrow surface of the crystallizer 2, and is equipped with two vertical stirring magnetic poles 4, which constitute a vertical electromagnetic stirring device, and each vertical stirring magnetic pole 4 is equipped with six inner sides. A stirring iron core 6, each stirring iron core 6 is equipped with a stirring coil 7.

The traveling wave magnetic field generated by the horizontal electromagnetic stirring device on both sides of the wide surface of the crystallizer 2 can drive the molten metal in the magnetic field area to move relatively horizontally.

The horizontal electromagnetic stirring device is equipped with two horizontal stirring magnetic poles 5, which are arranged face to face on both sides of the wide surface of the crystallizer 2, and each horizontal stirring magnetic pole 5 is equipped with three stirring iron cores 6 inside, and each stirring iron core 6 is A stirring coil 7 is provided.

The jet-type electromagnetic braking device adopts the form of a constant DC magnetic field, and the jet-type electromagnetic braking device is excited on both sides of the wide surface of the crystallizer 2 to generate a stable and constant DC magnetic field perpendicular to the wide surface of the slab mold 2, which can directly drive the submerged nozzle 1 The molten metal in the flow area of the exit jet is in relative motion.

The rectangular magnetic poles 8 of the jet-type electromagnetic braking device correspond to the magnetic yoke, and the outer surfaces of the rectangular magnetic poles 8 are equipped with excitation coils 9 , and the outer surfaces of the excitation coils 9 are in clearance fit with the inner surface of the magnetic yoke and the outer surface of the crystallizer 2 .

The jet-type electromagnetic braking device is equipped with four rectangular magnetic poles 8, two rectangular magnetic poles 8 located on the same side of the wide surface of the crystallizer 2 form a jet-type electromagnetic braking device, and two rectangular magnetic poles 8 located on the other side of the wide surface of the mold 2 The magnetic pole 8 constitutes another jet-type electromagnetic braking device, and the two jet-type electromagnetic braking devices are arranged face to face.

The upper surface of the vertical stirring magnetic pole 4 of the two vertical electromagnetic stirring devices is 5-150 mm higher than the surface 3 of the molten metal, and the thickness of the vertical stirring magnetic pole 4 along the width direction of the crystallizer 2 is 50-400 mm. The magnetic pole thickness of the magnetic pole 4 along the height direction of the crystallizer 2 is 150-1000mm, the electromagnetic stirring frequency of the vertical stirring magnetic pole 4 is 0.01-10Hz, and the AC power supply of the stirring coil 7 is 0.01-6000A.

The vertical stirring magnetic pole 4 of the first type of vertical electromagnetic stirring device can freely rotate in the height direction of the crystallizer 2, and the rotation angle is between -60°～60°. The outer surface of the vertical stirring magnetic pole 4 is in contact with the crystallizer 2 The distance L1 between the narrow surfaces is 0-200mm, and the distance L2 between the inner surfaces of the vertical stirring magnetic poles 4 located on the same side of the wide surface of the crystallizer 2 is 500-1500mm.

In the second type of vertical electromagnetic stirring device, the inner surface of the stirring iron core 6 is 0-200 mm away from the narrow surface of the crystallizer.

The ratio of the minimum distance between the magnetic pole thickness of the vertical stirring magnetic pole 4 along the height direction of the crystallizer 2 and the surface 3 of the molten metal to the upper surface of the rectangular magnetic pole 8 of the jet type electromagnetic brake device is greater than 0.5, and the lower surface of the vertical stirring magnetic pole 4 is in the same direction as the rectangular magnetic pole 8. The minimum distance between the upper surfaces of the magnetic poles 8 is greater than 50 mm.

The upper surface of the horizontal stirring magnetic pole 5 of the horizontal electromagnetic stirring device is 5 ^to 150mm higher than the surface 3 of the molten metal, the thickness of the horizontal stirring magnetic pole 5 along the width direction of the crystallizer 2 is 50 to 500mm, and the horizontal stirring magnetic pole 5 is along the direction of the crystallizer 2. The thickness of the magnetic pole in the height direction is 50-500 mm, the distance L3 between the outer surface of the horizontal stirring magnetic pole 5 and the narrow surface of the crystallizer 2 is 150-400 mm, the electromagnetic stirring frequency of the horizontal stirring magnetic pole 5 is 0.01-10 Hz, and the alternating current of the stirring coil 7 The power supply is 0.01～6000A.

The rectangular magnetic pole 8 of the jet type electromagnetic braking device can freely rotate in the width direction of the crystallizer 2, and the rotation angle is between -60° and 60°. The upper surface of the rectangular magnetic pole 8 and the lower surface of the submerged nozzle 1 bottom The minimum distance is 50-300mm, the magnetic pole thickness of the rectangular magnetic pole 8 along the height direction of the crystallizer 2 is 10-1000mm, the magnetic pole thickness of the rectangular magnetic pole 8 along the width direction of the mold 2 is 50-400mm, and the stable magnetic field between the rectangular magnetic poles 8 The magnetic induction intensity is 0.01~3T.

The multi-segment independently adjustable composite magnetic field device of the present invention can be freely adjusted according to the width change of the crystallizer 2, wherein the vertical electromagnetic stirring device can be freely selected in the width direction or height direction of the crystallizer 2 and the horizontal electromagnetic stirring device, jet The combined position of the type electromagnetic brake device is used to realize the divisional control of the molten metal flow in the crystallizer 2.

The multi-stage independently adjustable composite magnetic field device and method of the present invention can adjust the operating modes of the vertical electromagnetic stirring device, the horizontal electromagnetic stirring device and the jet electromagnetic braking device in real time on-line by means of the power supply phase according to different casting conditions, so as to It is beneficial to flexibly control the flow of molten metal in the crystallizer 2, especially near the meniscus. When the casting speed is high, the operation of the vertical electromagnetic stirring device, the horizontal electromagnetic stirring device and the jet electromagnetic braking device can control the vicinity of the meniscus, the vicinity of the entrance of the submerged nozzle 1 on the surface of the molten metal, and the outlet of the submerged nozzle 1. The purpose of decelerating the flow of the molten metal is to reduce the fluctuation of the meniscus near the narrow surface of the mold 2 and reduce the risk of eddies, thereby helping to reduce the entrainment of mold slag in high-speed continuous casting. At low casting speed, the operation modes of vertical electromagnetic stirring device and horizontal electromagnetic stirring device are opposite to those at high casting speed. The solidification length of the billet shell improves the cleaning effect on the solidification front, thereby helping to reduce the inclusions, air bubbles and meniscus freezing on the surface and subcutaneous.

A multi-segment independently adjustable composite magnetic field method for controlling the flow of molten metal in a crystallizer 2, using a multi-segment independently adjustable composite magnetic field device for controlling the flow of molten metal in the mold 2 in a partitioned manner, comprising the following steps:

Step 1, during the continuous casting process, the molten metal enters the crystallizer 2 through the submerged nozzle 1, and the molten metal flowing out from the outlet of the submerged nozzle 1 hits the narrow surface of the mold 2 to form an upper backflow and a lower backflow;

Step 2, connect the three-phase low-frequency power supply to the vertical type electromagnetic stirring device and the horizontal type electromagnetic stirring device, and connect the DC power supply to the jet type electromagnetic braking device at the same time, which can respectively form a vertical traveling wave magnetic field, a horizontal traveling wave magnetic field and Steady DC magnetic field. The vertical traveling wave magnetic field generated by the vertical electromagnetic stirring device drives the relative movement of the metal liquid from the jet impact area to the meniscus area, and at the same time, it can inhibit the impact of the upper backflow metal liquid on the meniscus and the metal near the narrow surface of the crystallizer 2. The impact of the liquid surface. The horizontal traveling wave magnetic field generated by the horizontal electromagnetic stirring device drives the molten metal in the free surface area of the mold 2 to move relatively horizontally, while maintaining the activity of the meniscus and the slag layer attached to the molten metal surface, thereby preventing the crystallizer from 2. When the flow rate of molten metal on the upper liquid surface is too low, the molten slag solidifies to form a slag circle. The steady DC magnetic field generated by the jet-type electromagnetic braking device drives the molten metal in the jet flow area at the outlet of the submerged nozzle 1 to make relative motion, and at the same time, it can reduce the penetration depth of the molten metal from the downflow to the molten pool of the mold 2, and promote the crystallizer. 2 Floating and removal of heterogeneous substances such as non-metallic inclusions and bubbles entrained in the molten metal in the central area.

Example:

Example 1

This implementation adopts the multi-stage independently adjustable composite magnetic field device as shown in Figure 1, wherein the horizontal stirring magnetic pole 4 of the horizontal electromagnetic stirring device has a magnetic pole thickness of 390mm along the width direction of the crystallizer 2, and a magnetic pole thickness along the height direction of the crystallizer 2 The vertical stirring magnetic pole 4 of the vertical type electromagnetic stirring device has a magnetic pole thickness of 390 mm along the height direction of the crystallizer 2, and the magnetic pole thickness along the width direction of the crystallizer 2 is 100 mm. The rectangular magnetic pole 7 of the jet type electromagnetic braking device is along the The thickness of the magnetic poles in the height direction of the mold 2 is 90 mm, the thickness of the magnetic poles in the width direction of the mold 2 is 350 mm, the cross-sectional size of the mold 2 is 1060 mm × 100 mm, and the central plane of the thickness of the mold 2 is along the magnetic field in the height direction of the mold 2 Distribution.

A multi-stage independently adjustable compound magnetic field method for controlling the flow of molten metal in a mold 2, using a multi-stage independently adjustable composite magnetic field device for controlling the flow of molten metal in the mold 2, comprising the following steps:

Step 1, during the continuous casting process, the molten metal enters the crystallizer 2 through the submerged nozzle 1, and the molten metal flowing out from the outlet of the submerged nozzle 1 hits the narrow surface of the mold 2 to form an upper backflow and a lower backflow;

Step 2: After passing in a current of 800A to the horizontal electromagnetic stirring device of the multi-segment independently adjustable composite magnetic field device, passing in a current of 500A to the vertical electromagnetic stirring device, and passing in a current of 300A to the jet type electromagnetic braking device, the vertical type The electromagnetic stirring device and the horizontal electromagnetic stirring device generate a vertical traveling wave magnetic field and a horizontal traveling wave magnetic field respectively, and the jet type electromagnetic braking device generates a steady DC magnetic field.

It can be seen from Figure 5 that when the multi-segment independently adjustable composite magnetic field device is connected to the three-phase low-frequency power supply and DC power supply, the vertical traveling wave magnetic field generated by the vertical electromagnetic stirring device can cover the jet impact area, meniscus area and crystallization area. Three key areas of the upper reflow zone of the crystallizer 2, thereby effectively controlling the direct impact of the upper reflow metal liquid on the meniscus near the narrow surface of the crystallizer 2. The horizontal traveling wave magnetic field generated by the horizontal electromagnetic stirring device can cover the molten metal surface 3 and the area near the entrance of the submerged nozzle 1, which not only maintains the activity of the meniscus and the molten metal surface 3 attached slag layer, but also avoids the solidification of molten metal A slag ring is formed. The steady DC magnetic field generated by the jet-type electromagnetic braking device can directly cover the metal jet flow area at the outlet of the submerged nozzle 1, preferentially suppressing the impact of the metal liquid at the outlet of the submerged nozzle 1 on the narrow surface of the crystallizer, and reducing the impact of the downflow metal liquid on the crystallization The penetration depth of the molten pool of the crystallizer 2, thereby promoting the floating removal of non-metallic inclusions, bubbles and other heterogeneous substances entrained in the molten metal in the central area of the crystallizer 2.

Since the vertical type electromagnetic stirring device, the horizontal type electromagnetic stirring device and the jet type electromagnetic braking device are not connected to each other and each has an independent power supply system, it is more flexible in controlling the flow of molten metal in the key area of the crystallizer 2, The current intensity of each system can be adjusted independently according to different casting conditions.

Example 2.

This implementation adopts the multi-stage independently adjustable composite magnetic field device as shown in Figure 1, wherein the horizontal stirring magnetic pole 4 of the horizontal electromagnetic stirring device has a magnetic pole thickness of 390mm along the width direction of the crystallizer 2, and a magnetic pole thickness along the height direction of the crystallizer 2 The vertical stirring magnetic pole 4 of the vertical type electromagnetic stirring device has a magnetic pole thickness of 390 mm along the height direction of the crystallizer 2, and the magnetic pole thickness along the width direction of the crystallizer 2 is 100 mm. The rectangular magnetic pole 7 of the jet type electromagnetic braking device is along the The thickness of the magnetic poles in the height direction of the mold 2 is 90mm, the thickness of the magnetic poles in the width direction of the mold 2 is 350mm, the cross-sectional size of the mold 2 is 1060mm×100mm, and the surface 3 of the liquid metal of the mold 2 is along the width direction of the mold 2 Lorentz force distribution diagram.

A multi-stage independently adjustable compound magnetic field method for controlling the flow of molten metal in a mold 2, using a multi-stage independently adjustable composite magnetic field device for controlling the flow of molten metal in the mold 2, comprising the following steps:

Step 1, during the continuous casting process, the molten metal enters the crystallizer 2 through the submerged nozzle 1, and the molten metal flowing out from the outlet of the submerged nozzle 1 hits the narrow surface of the mold 2 to form an upper backflow and a lower backflow;

Step 2. When the multi-segment independently adjustable composite magnetic field device is running, the current intensity of the horizontal electromagnetic stirring device, vertical electromagnetic stirring device and jet-type electromagnetic braking device can be adjusted independently, and the multi-segment independently adjustable composite magnetic field The horizontal electromagnetic stirring device of the device is fed with a current of 600A, the vertical electromagnetic stirring device is fed with a current of 500A, and the jet type electromagnetic braking device is fed with a current of 300A. The type traveling wave magnetic field and the horizontal traveling wave magnetic field, and the jet type electromagnetic braking device produces a steady DC magnetic field.

It can be seen from Fig. 6 that the Lorentz force on the horizontal section 3 along the width direction of the mold 2 at a position 65 mm below the molten metal surface of the mold 2 is in a vortex distribution, which can drive the metal on the surface 3 of the molten metal and the area near the entrance of the submerged nozzle 1. The fluid moves horizontally. It can be seen that the Lorentz force generated by the horizontal electromagnetic stirring device can maintain the activity of the attached slag layer on the meniscus and the molten metal surface 3 while increasing the flow velocity of the molten metal surface 3 and the area near the entrance of the submerged nozzle 1 , improve the melting conditions of the mold slag, and then prevent the slag from solidifying to form a slag ring.

The multi-segment independently adjustable composite magnetic field device adopts vertical electromagnetic stirring device, horizontal electromagnetic braking device and jet electromagnetic braking device, so that the composite magnetic field generated by it can more effectively partition and control the molten metal in the mold Flow, while the multi-segment independently adjustable composite magnetic field device uses different magnetic field forms, electromagnetic force magnitudes and action positions to precisely control the composite magnetic field, thereby obtaining high-quality metal liquid flow state and improving the quality of casting slabs.

It can be understood that the above specific descriptions of the present invention are only used to illustrate the present invention and are not limited to the technical solutions described in the embodiments of the present invention. Those of ordinary skill in the art should understand that the present invention can still be modified or Equivalent replacements to achieve the same technical effect; as long as they meet the needs of use, they are all within the protection scope of the present invention.

Claims (6)

1. The utility model provides a multistage position independently adjustable compound magnetic field device that control molten metal flows which characterized in that: comprises three parts: a vertical electromagnetic stirring device, a horizontal electromagnetic stirring device and a jet type electromagnetic braking device; the three parts independently adjust the current intensity according to different casting conditions, and the flow of the molten metal in the slab continuous casting crystallizer is controlled in a partitioning way;

the vertical electromagnetic stirring device comprises a vertical stirring magnetic pole, a stirring iron core and a stirring coil, wherein the stirring coil is sleeved outside the stirring iron core, the stirring magnetic pole is arranged at the outer end part of the stirring iron core, and the vertical stirring magnetic pole, the stirring iron core and the stirring coil form an integrated structure; two of the two groups are combined into a group, symmetrically arranged on the wide surface or the narrow surface of the crystallizer; the traveling wave magnetic field generated by the vertical electromagnetic stirring device can drive the jet impact area to the molten metal in the meniscus area to do relative motion; when the vertical electromagnetic stirring device is arranged on the wide surface of the crystallizer, three stirring iron cores are arranged on the inner side of each vertical stirring magnetic pole; when the vertical electromagnetic stirring device is arranged on the narrow surface of the crystallizer, six stirring iron cores are arranged on the inner side of each vertical stirring magnetic pole;

the horizontal electromagnetic stirring device comprises a horizontal stirring magnetic pole, a stirring iron core and a stirring coil, wherein the stirring coil is sleeved outside the stirring iron core, the stirring magnetic pole is arranged at the outer end part of the stirring iron core, and the horizontal stirring magnetic pole, the stirring iron core and the stirring coil form an integrated structure; three stirring iron cores are arranged on the inner side of each horizontal stirring magnetic pole, and each stirring iron core is provided with a stirring coil; the horizontal electromagnetic stirring devices are arranged on the wide surface of the crystallizer and on two sides of molten metal in a pair by pair mode; the traveling wave magnetic field generated by the horizontal electromagnetic stirring device on the two sides of the wide surface of the crystallizer can drive the molten metal in the magnetic field area to do relative horizontal movement;

the jet-type electromagnetic braking device comprises an integrated structure formed by rectangular magnetic poles, magnetic yokes and exciting coils, wherein the jet-type electromagnetic braking devices are arranged on two sides of a molten metal flowing area of a wide surface of a crystallizer and an immersed nozzle outlet in a symmetrical mode; the jet type electromagnetic braking device adopts a stable constant direct current magnetic field form, and the jet type electromagnetic braking device is excited at two sides of the wide surface of the crystallizer to generate a stable constant direct current magnetic field perpendicular to the wide surface of the slab crystallizer so as to directly drive molten metal in a jet flow flowing area at an outlet of the submerged nozzle to perform relative motion; the rectangular magnetic poles and the magnetic yokes correspond to each other, exciting coils are arranged on the outer sides of the rectangular magnetic poles, and the outer surfaces of the exciting coils are in clearance fit with the inner surfaces of the magnetic yokes and the outer surfaces of the crystallizers;

the upper surface of the vertical stirring magnetic pole of the vertical electromagnetic stirring device is 5-150 mm higher than the surface of the molten metal, the electromagnetic stirring frequency of the vertical stirring magnetic pole is 0.01-10 Hz, and the alternating current power supply of the stirring coil is 0.01-6000A;

when the vertical electromagnetic stirring device is positioned on the wide surface of the crystallizer, the vertical stirring magnetic pole can freely rotate in the height direction of the crystallizer, the rotation angle is between-60 degrees and 60 degrees, the distance L1 between the outer surface of the vertical stirring magnetic pole and the narrow surface of the crystallizer is 0-200 mm, and the distance L2 between the inner surfaces of the vertical stirring magnetic poles positioned on the same side of the wide surface of the crystallizer is 500-1500 mm;

the height of the upper surface of the horizontal stirring magnetic pole of the horizontal electromagnetic stirring device, which is higher than the surface of the molten metal, is 5-150 mm;

the distance L3 between the outer surface of the horizontal stirring magnetic pole and the narrow surface of the crystallizer is 150-400 mm, the electromagnetic stirring frequency of the horizontal stirring magnetic pole is 0.01-10 Hz, and the alternating current power supply of the stirring coil is 0.01-6000A;

the rectangular magnetic pole of the jet-type electromagnetic braking device can freely rotate in the width direction of the crystallizer, the rotation angle is between-60 degrees and 60 degrees, the minimum distance between the upper surface of the rectangular magnetic pole and the lower surface of the bottom of the immersed nozzle is 50-300 mm,

the magnetic induction intensity of the steady magnetic field between the rectangular magnetic poles is 0.01-3T;

the vertical electromagnetic stirring device can freely select the combination arrangement position of the horizontal electromagnetic stirring device and the jet-type electromagnetic braking device in the width direction or the height direction of the crystallizer.

2. The multi-stage independently adjustable composite magnetic field device for controlling the flow of molten metal according to claim 1, wherein: the thickness of the vertical stirring magnetic pole along the width direction of the crystallizer is 50-400 mm, and the thickness of the vertical stirring magnetic pole along the height direction of the crystallizer is 150-1000 mm.

3. The multi-stage independently adjustable composite magnetic field device for controlling the flow of molten metal according to claim 2, wherein: the magnetic pole thickness of the horizontal stirring magnetic pole along the width direction of the crystallizer is 50-500 mm, and the magnetic pole thickness of the horizontal stirring magnetic pole along the height direction of the crystallizer is 50-500 mm.

4. A multi-stage independently adjustable composite magnetic field device for controlling molten metal flow according to claim 3, wherein: the magnetic pole thickness of the rectangular magnetic pole along the height direction of the crystallizer is 10-1000 mm, and the magnetic pole thickness of the rectangular magnetic pole along the width direction of the crystallizer is 50-400 mm.

5. The multi-stage independently adjustable composite magnetic field device for controlling the flow of molten metal according to claim 1, wherein: at high pulling speed, the running of the vertical electromagnetic stirring device, the horizontal electromagnetic stirring device and the jet electromagnetic braking device decelerates the flow of the metal liquid which is controlled by the vertical electromagnetic stirring device, the horizontal electromagnetic stirring device and the jet electromagnetic braking device; at low pull rates, the operation modes of the vertical electromagnetic stirring device and the horizontal electromagnetic stirring device are opposite to those of the high pull rates, so that the flow rates of the metal liquid controlled by the vertical electromagnetic stirring device and the horizontal electromagnetic stirring device are improved.

6. A multi-stage independently adjustable composite magnetic field method for controlling the flow of molten metal, characterized in that the multi-stage independently adjustable composite magnetic field device for controlling the flow of molten metal according to any one of claims 1 to 5 comprises the following steps:

in the continuous casting process, molten metal enters a crystallizer through a submerged nozzle, and the molten metal flowing out of an outlet of the submerged nozzle is impacted to a narrow surface of the crystallizer to form an upper reflux and a lower reflux;

step 2, connecting the vertical type electromagnetic stirring device and the horizontal type electromagnetic stirring device to a three-phase low-frequency power supply, and connecting the jet type electromagnetic braking device to a direct-current power supply to form a vertical traveling wave magnetic field, a horizontal traveling wave magnetic field and a steady direct-current magnetic field respectively; the vertical traveling wave magnetic field generated by the vertical electromagnetic stirring device can inhibit the upward backflow of the molten metal from impacting the meniscus and the molten metal level near the narrow surface of the crystallizer while driving the jet impact area to make relative movement to the molten metal in the meniscus area; the horizontal traveling wave magnetic field generated by the horizontal electromagnetic stirring device drives the molten metal in the free surface area of the crystallizer to do relative horizontal movement, and can keep the activity of the meniscus and the molten metal surface attached slag layer, so that slag solidification is avoided to form a slag ring when the flow rate of the molten metal on the liquid surface of the crystallizer is too low; the stable direct current magnetic field generated by the jet electromagnetic braking device drives the molten metal in the jet flow flowing area of the outlet of the immersion nozzle to move relatively, so that the penetration depth of the molten metal flowing back downwards to a molten pool of the crystallizer can be reduced, and the floating removal of nonmetallic inclusion and bubbles entrained by the molten metal in the central area of the crystallizer is promoted.

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