Slab continuous casting multi-zone composite electromagnetic braking device

Abstract

The invention discloses a slab continuous casting multi-zone composite electromagnetic braking device which comprises a first electromagnetic brake, a second electromagnetic brake and a third electromagnetic brake. The first electromagnetic brake is arranged on the outer side of a wide-surface copper plate in the crystallizer, corresponds to a horizontal oblique jet flow of molten steel discharged from the submersed nozzle, and is arranged in a horizontal oblique downward direction; the second electromagnetic brakes are arranged on the outer side of a wide-surface copper plate in the crystallizer, are positioned below the first electromagnetic brake, correspond to underwater backflow of molten steel, and are symmetrically arranged on the two sides of the center line of the crystallizer; the third electromagnetic brake is arranged on the outer side of a wide-face copper plate in the crystallizer, located above the first electromagnetic brake, corresponding to molten steel upper backflow and liquid level fluctuation, arranged in the horizontal direction and covers the width of the wide-face copper plate. A series of problems of low electromagnetic braking force, small action area, heavy equipment, inconvenience in adjustment, high energy consumption, limited effect and the like of molten steel flowing in the crystallizer are solved.

Description

Technical Field

[0001] The invention relates to a slab continuous casting technology, and more specifically to a slab continuous casting multi-zone composite electromagnetic braking device. Background Art

[0002] High-grade automobile plates, home appliance plates, construction steel, electrical steel, etc. have increasingly higher requirements for the control of inclusion content in steel. In the slab continuous casting process, the flow rate of the molten steel flowing out of the crystallizer's submerged nozzle can often reach about 1m / s. The high-speed molten steel impacts the initial solidified shell of the narrow surface of the crystallizer. On the one hand, it is easy to remelt the initial shell and even cause leakage accidents. On the other hand, it will also cause the solidification interface to capture inclusions in the solidified shell to form steel defects. After the molten steel flows out from the holes on both sides of the bottom of the nozzle, it generally tilts in the horizontal downward direction. After hitting the narrow surface of the crystallizer, it forms two large upper and lower reflux areas. Among them, the upper reflux impacts the liquid surface to cause liquid surface fluctuations, which easily causes the protective slag covered on the steel surface to roll up, causing subcutaneous inclusions; the lower reflux has a greater penetration depth, often reaching several meters, which makes it difficult for non-metallic inclusions in the molten steel to float up with the molten steel to the depth of the crystallizer, and finally forms internal inclusions. With the continuous increase in modern continuous casting speed, this problem has a tendency to further deteriorate. Therefore, how to reasonably control the flow field of molten steel in the crystallizer is the key to improving the quality and efficiency of slab continuous casting.

[0003] Practice has proved that the electromagnetic brake EMBR technology induces a circular current through the action of an external magnetic field and the flowing molten steel in the crystallizer, generating a braking force in the opposite direction of the movement of the molten steel, thereby slowing down the flow rate of the molten steel in the crystallizer. It can promote common 10-100μm or even larger non-metallic oxide inclusions, entrapped protective slag, peeling refractory materials, etc. to fully float in the molten steel and be adsorbed on the protective slag layer on the top of the crystallizer molten pool and finally be removed, which is beneficial to improve the purity or cleanliness of the steel billet and avoid defects such as inclusions, slag inclusions, hot cracking, etc. It is an indispensable and important tool for continuous casting production of high-quality billets. In 1980, ABB of Sweden and Kawasaki Steel of Japan jointly developed the first generation of regional electromagnetic brake device EMBR (+, -), that is, local magnetic field electromagnetic braking technology. By setting a regional constant magnetic field on the wide side of the crystallizer and on both sides of the submerged water nozzle, the flow speed and direction of the molten steel flowing out of the submerged water nozzle are controlled, the erosion of the narrow surface billet shell by the molten steel is reduced, and the fluctuation of the liquid level is suppressed, thereby reducing the probability of slag rolls and inclusion defects on the surface of the ingot. However, due to the limited range of action of the magnetic field, there are problems such as insufficient braking effect, difficulty in suppressing liquid level fluctuations, and inability to change operating parameters. In 1991, the second generation of electromagnetic brakes using a horizontal magnetic field covering the entire width of the slab were installed and tested at Sollac in France and Hoogovens in the Netherlands. This method, called EMBR Ruler or LMF (Level DC Magnetic Field), can achieve a more stable electromagnetic braking effect with less sensitivity to different casting conditions. However, the electromagnetic brake is greatly affected by position. If the magnetic field is slightly far from the water outlet or the water outlet outflow angle is slightly inappropriate, the braking effect will be affected, and even only the downward reflux will be suppressed, while the liquid level fluctuation is still difficult to control. The flow control mold (FC mold) is the third generation electromagnetic brake device developed by Kawasaki Steel Corporation of Japan. It consists of two horizontal magnetic fields covering the entire width of the slab. One magnetic field is at the meniscus, and the other magnetic field is applied oppositely below the immersed nozzle. It can simultaneously reduce the flow rate of the molten steel at the meniscus and the downward flow rate of the molten steel at the bottom of the crystallizer. Later, the FC mold II technology appeared, which controlled the two sections of magnetic flux density separately through independent wiring and independent power supply. The surface flow rate can be optimized by controlling the upper magnetic pole.

[0004] Among the existing patent applications, Japanese patent JP19870090634 uses bolts to fix the electromagnets at different positions on the back plate, manually adjusts the position of the magnetic poles, and seeks the electromagnetic braking action area with the best effect. Chinese patent CN97113854.0 divides the magnetic field of electromagnetic braking into an upper magnetic field and a lower magnetic field to improve the calm state of the molten steel pool and reduce the turbulence in the molten steel pool. Chinese patent CN98801009.7 independently controls the current supplied to the electromagnetic coils of the upper and lower electromagnets to facilitate changing the braking strength of the upper and lower magnetic fields. Chinese patent CN01254464.7 sets a DC electromagnetic coil and a horseshoe yoke above the liquid level of the crystallizer molten pool, and through the left and right static magnetic fields, it slows down the impact of molten steel on the molten pool and suppresses the fluctuation of the molten pool. Japanese patent JP20020067560 provides a magnetic pole and magnetic circuit design scheme for an electromagnetic brake device used in multi-stream continuous casting. International patent WO2002SE00030 arranges an electromagnetic device on the narrow side of the crystallizer to electromagnetically brake the flow of molten steel near the narrow side. Japanese patent JP20070298484 discloses an electromagnetic coil device that allows electromagnetic stirring or electromagnetic braking to selectively act on molten steel. Chinese patent CN200980127917.5 symmetrically arranges at least two magnetic poles on the wide side of the crystallizer, and makes the magnetic poles form a certain angle (α1 or α2) with the mid-vertical line. Chinese patent CN201610580291.5 involves a vertical electromagnetic braking device, which is arranged near the two side areas of the crystallizer to generate a steady-state braking magnetic field between the horizontal magnetic poles and the vertical magnetic poles.

[0005] It can be seen that the existing electromagnetic braking technology has the following shortcomings:

[0006] (1) The magnetic field strength is not high enough. Generally, the better ones can only reach 0.1 to 0.3 T, and they mostly act on the local area where the molten steel flows. The electromagnetic braking force is relatively insufficient and the final metallurgical effect is limited.

[0007] (2) The energy conversion efficiency is low. Due to the magnetic core, a lot of electrical energy is lost in ohmic heat and its cooling, and a lot of magnetic energy is lost in the structural space.

[0008] (3) The adjustment and use are not convenient and flexible enough. Since most magnetic poles are fixed mechanically, the position and angle cannot be adjusted online. At best, only the braking current can be adjusted.

[0009] (4) The electromagnetic brake device has a complex structure and the iron core has a large weight, so there are many difficulties or problems in installing it on a traditional vibrating crystallizer.

[0010] (5) It is closely related to the low conversion efficiency of the device and has a high demand for energy media such as power supply and cooling water.

[0011] Therefore, actively developing high-quality, efficient and low-consumption continuous casting technology, especially the new electromagnetic braking technology that uses electromagnetic fields to control and optimize the flow state of molten steel in the crystallizer to further improve the quality and efficiency of continuous casting, has significant economic and social benefits. It is not only important but also very urgent, especially today when we continue to emphasize "green" and "low-carbon" development. Summary of the invention

[0012] In view of the defects existing in the prior art, the purpose of the present invention is to provide a slab continuous casting multi-zone composite electromagnetic braking device to solve a series of problems such as weak electromagnetic braking force of molten steel flow in the crystallizer, small effective area, heavy equipment, inconvenient adjustment, high energy consumption and limited effect.

[0013] To achieve the above object, the present invention adopts the following technical solution:

[0014] A slab continuous casting multi-zone composite electromagnetic brake device comprises a first electromagnetic brake, a second electromagnetic brake and a third electromagnetic brake;

[0015] The first electromagnetic brake is arranged on the outside of the wide copper plate in the crystallizer, corresponding to the horizontal oblique jet of molten steel coming out of the submerged nozzle, and arranged in a horizontal oblique downward direction;

[0016] The second electromagnetic brake is arranged on the outer side of the wide copper plate in the crystallizer and below the first electromagnetic brake, corresponding to the reflux of molten steel, and symmetrically arranged on both sides of the center line of the crystallizer;

[0017] The third electromagnetic brake is arranged on the outside of the wide copper plate in the crystallizer and above the first electromagnetic brake, corresponding to the upward reflux of molten steel and the fluctuation of liquid level, and is arranged in a horizontal direction to cover the width of the wide copper plate.

[0018] Preferably, the first electromagnetic brake comprises a left first electromagnetic brake mechanism and a right first electromagnetic brake mechanism respectively arranged on both sides of the vertical center line of the crystallizer;

[0019] An included angle α between the symmetry center lines of the left first electromagnetic brake mechanism and the right first electromagnetic brake mechanism and the vertical center line of the crystallizer is 60° to 90°.

[0020] Preferably, the second electromagnetic brake comprises a left second electromagnetic brake mechanism and a right second electromagnetic brake mechanism respectively arranged on both sides of the vertical center line of the crystallizer;

[0021] An included angle β between the symmetry center lines of the left second electromagnetic brake mechanism and the right second electromagnetic brake mechanism and the vertical center line of the crystallizer is 0° to 30°.

[0022] Preferably, the left first electromagnetic brake mechanism, the right first electromagnetic brake mechanism, the left second electromagnetic brake mechanism, and the right second electromagnetic brake mechanism all include a magnetic core, an electromagnetic coil, a power supply, and a hydraulic cylinder;

[0023] The electromagnetic coil is wound around the magnetic core;

[0024] The power supply is connected to the electromagnetic coil;

[0025] The hydraulic cylinder adjusts the direction of the magnetic core to adjust the angle α and the angle β.

[0026] Preferably, the third electromagnetic brake comprises a magnetic core, an electromagnetic coil, a power supply, a left hydraulic cylinder and a right hydraulic cylinder;

[0027] The magnetic core is horizontally arranged on the outer side of the wide copper plate;

[0028] The electromagnetic coil is wound around the magnetic core;

[0029] The power supply is connected to the electromagnetic coil;

[0030] The left hydraulic cylinder is arranged at the left end of the magnetic core, and the right hydraulic cylinder is arranged at the right end of the magnetic core, so as to adjust the vertical distance L between the third brake and the upper edge of the crystallizer. p .

[0031] Preferably, the magnetic core of the first electromagnetic brake, the second electromagnetic brake and the third electromagnetic brake comprises an inner core and a shell covering the outer surface of the inner core;

[0032] The inner core is made of a high magnetic permeability material;

[0033] The shell is made of electromagnetic pure iron.

[0034] Preferably, the high magnetic permeability material is a soft magnetic ferrite composed of iron oxide and other compounds containing one or more elements of manganese, zinc, nickel and magnesium.

[0035] Preferably, the other compound is an oxide containing one or more elements of manganese, zinc, nickel and magnesium, or a carbonate compound containing one or more elements of manganese, zinc, nickel and magnesium.

[0036] Preferably, the hydraulic cylinder is an electric cylinder.

[0037] Preferably, the left hydraulic cylinder and the right hydraulic cylinder are electric cylinders.

[0038] The slab continuous casting multi-zone composite electromagnetic braking device provided by the present invention has the following beneficial effects:

[0039] 1) Compared with the traditional electromagnetic braking technology, the slab continuous casting multi-zone composite electromagnetic braking device of the present invention has a large action range, high electromagnetic conversion efficiency, and a strong braking magnetic field, and is particularly suitable for use in high-speed continuous casting;

[0040] 2) Compared with the traditional electromagnetic braking technology, the slab continuous casting multi-zone composite electromagnetic braking device of the present invention has light weight, strong adjustment ability, low energy consumption, and is flexible and convenient to use;

[0041] 3) Compared with the traditional electromagnetic braking technology, the multi-zone composite electromagnetic braking device for slab continuous casting of the present invention performs step-by-step and composite electromagnetic braking on the entire flow area of ​​molten steel in the crystallizer, and the molten steel purification effect is more obvious, avoiding defects such as inclusions, slag inclusions, and thermal cracks (cracks often initiate and expand at inclusions), thereby improving the continuous casting quality and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the flow of molten steel in the crystallizer;

[0043] Figure 2 It is a structural schematic diagram of the slab continuous casting multi-zone composite electromagnetic braking device of the present invention;

[0044] Figure 3 It is a schematic diagram of the arrangement of magnetic poles in the slab continuous casting multi-zone composite electromagnetic braking device of the present invention;

[0045] Figure 4 It is a three-dimensional schematic diagram of the magnetic core in the slab continuous casting multi-zone composite electromagnetic braking device of the present invention;

[0046] Figure 5 It is a schematic cross-sectional view of a magnetic core in a slab continuous casting multi-zone composite electromagnetic braking device of the present invention. DETAILED DESCRIPTION

[0047] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0048] Combination Figure 1 and Figure 2 As shown, a slab continuous casting multi-zone composite electromagnetic brake device provided by the present invention matches the main flow path of molten steel in the crystallizer. Along the flow direction of the molten steel, in the entire flow area of ​​the molten steel, three-level electromagnetic brakes are arranged in different areas, including a first electromagnetic brake, a second electromagnetic brake and a third electromagnetic brake.

[0049] The first electromagnetic brake is arranged outside the wide copper plate 2 in the crystallizer, corresponding to the horizontal oblique jet V1 coming out of the immersion nozzle 1 (the angle with the vertical direction is α), and is arranged in a horizontal oblique downward direction.

[0050] The second electromagnetic brake is arranged outside the wide copper plate 2 in the crystallizer and below the first electromagnetic brake, corresponding to the downward flow of molten steel in the crystallizer, i.e., the downward reflux V2 (the angle with the vertical direction is β), and is arranged in a vertically oblique direction to the middle.

[0051] The third electromagnetic brake is arranged outside the position of the fluctuating liquid surface, i.e., the meniscus 4, in the crystallizer, and is located above the first electromagnetic brake, corresponding to the upward flow of molten steel in the crystallizer, i.e., the upward reflux V3 and the liquid surface fluctuation, and is arranged in a horizontal direction, covering the width of the wide copper plate 2.

[0052] By arranging the braking force of the three-stage electromagnetic brake, the flow process of the molten steel is controlled step by step and coordinated in the entire flow basin according to the actual situation, so as to comprehensively achieve the purpose of effectively reducing the impact depth of the molten steel flow, suppressing the meniscus liquid level fluctuation, and avoiding the occurrence of quality defects such as inclusions / slag rolls / cracks.

[0053] The braking magnetic field of each level of electromagnetic brake is Figure 2 As shown, the magnetic force lines are from the wide copper plate 2 on one side of the crystallizer through the molten steel 5 to the wide copper plate 2 on the other side of the crystallizer. Figure 3 As shown, it includes one side magnetic core, one side magnetic pole 121 (N pole), one side wide copper plate 2, molten steel 5, the other side wide copper plate 2, the other side magnetic pole 121 (S pole), the other side magnetic core, etc., forming multiple, independent, closed magnetic field loops; each braking magnetic field is a static magnetic field generated by passing direct current through the electromagnetic coil, and the magnitude of the direct current or the magnetic field strength can be adjusted separately through their respective power supplies; the installation position and angle of each electromagnetic brake can be adjusted online through the action of the hydraulic cylinder.

[0054] The first electromagnetic brake corresponds to the horizontal oblique jet V1 coming out of the submerged water inlet 1, and comprises a left first electromagnetic brake mechanism and a right first electromagnetic brake mechanism respectively arranged on both sides of the vertical center line of the crystallizer.

[0055] The jet velocities at the left first electromagnetic brake mechanism and the right first electromagnetic brake mechanism are V 11 、V 12 The included angles between the symmetry center lines of the left first electromagnetic braking mechanism and the right first electromagnetic braking mechanism and the vertical center line of the crystallizer are α1 and α2 respectively, and the angles of the included angles α1 and α2 are 60° to 90°.

[0056] The left first electromagnetic brake mechanism is composed of an electromagnetic coil 111, a magnetic core 121, and a power supply 131. The DC current output by the power supply 131 can be adjusted. The electromagnetic coil 111 is wound around the magnetic core 121. The assembly of the magnetic core 121 and the electromagnetic coil 111 can adjust the angle α1 through a hydraulic cylinder 141.

[0057] The right first electromagnetic brake mechanism is composed of an electromagnetic coil 112, a magnetic core 122, and a power supply 132. The DC current output by the power supply 132 can be adjusted. The electromagnetic coil 112 is wound around the magnetic core 122. The assembly of the magnetic core 122 and the electromagnetic coil 112 can adjust the angle α2 through a hydraulic cylinder 142.

[0058] The second electromagnetic brake corresponds to the lower reflux V2, and comprises a left second electromagnetic brake mechanism and a right second electromagnetic brake mechanism respectively arranged on both sides of the vertical center line of the crystallizer.

[0059] The jet velocities at the left second electromagnetic brake mechanism and the right second electromagnetic brake mechanism are V 21 、V 22 The included angles between the symmetry center lines of the left second electromagnetic braking mechanism and the right second electromagnetic braking mechanism and the vertical center line of the crystallizer are β1 and β2 respectively, and the angles of the included angles β1 and β2 are 0° to 30°.

[0060] The left second electromagnetic brake mechanism is composed of an electromagnetic coil 211, a magnetic core 221, and a power supply 231. The DC current output by the power supply 231 can be adjusted. The electromagnetic coil 211 is wound around the magnetic core 221. The assembly of the magnetic core 221 and the electromagnetic coil 211 can adjust the angle β1 through a hydraulic cylinder 241.

[0061] The right second electromagnetic brake mechanism is composed of an electromagnetic coil 212, a magnetic core 222, and a power supply 232. The DC current output by the power supply 232 can be adjusted. The electromagnetic coil 212 is wound around the magnetic core 222. The assembly of the magnetic core 222 and the electromagnetic coil 212 can adjust the angle β2 through a hydraulic cylinder 242.

[0062] The third electromagnetic brake corresponds to the upper reflux V3 and the liquid level fluctuation, and is composed of an electromagnetic coil 310, a magnetic core 320, and a power supply 330. The DC current output by the power supply 330 can be adjusted. The components of the magnetic core 320 and the electromagnetic coil 310 can be adjusted to a distance from the upper edge of the crystallizer, i.e., a vertical position L, through left and right hydraulic cylinders 341 and 342. p size.

[0063] like Figure 4 and Figure 5 As shown, in order to further improve the electromagnetic conversion efficiency and braking efficiency, the magnetic core includes an inner core 22 and an outer shell 21 covering the outer surface of the inner core 22. The outer shell 21 is mainly used to ensure the overall strength of the magnetic core, and the inner core 22 is used to ensure the magnetic conductivity of the magnetic core. The inner core 22 is made of high magnetic conductivity material, and the outer shell 21 is made of electromagnetic pure iron.

[0064] High magnetic permeability material is soft magnetic ferrite, which is composed of iron oxide (Fe2O3) and other compounds containing one or more elements of manganese, zinc, nickel and magnesium. The ferrite raw material is made into a magnetic core for electromagnetic brakes through pressing, sintering, processing and assembly.

[0065] Other compounds are oxides containing one or more elements among manganese, zinc, nickel and magnesium, or carbonate compounds containing one or more elements among manganese, zinc, nickel and magnesium.

[0066] The magnetic permeability of ferrite is very high and the specific gravity is small. Generally, the relative magnetic permeability of soft ferrite is mr = 10000 ~ 30000, and the density is r = 4.8 ~ 4.9 × 10 3 kg / m 3 , while the relative magnetic permeability of electromagnetic pure iron is mr = 200 ~ 400, and the density is r = 7.8 × 10 3 kg / m 3 . Due to the improvement of the magnetic conductivity of the magnetic core, the electromagnetic conversion efficiency and magnetic field strength of the electromagnetic brake can be increased by more than 30-50%, which significantly improves the effect of electromagnetic braking. Due to the reduction in the specific gravity of the magnetic core, the weight of the brake device can be reduced by more than 30-50%, which is helpful for its installation and fixation on the back plate of the crystallizer, and also reduces the load of the crystallizer vibration mechanism. Since the magnetic core is made of high magnetic permeability material, the cross-sectional size of the magnetic core can be reduced by 30-50% under the condition of the same magnetic flux, which is conducive to the design and arrangement of the electromagnetic brake in the already quite limited space inside the crystallizer; at the same time, due to the high magnetic permeability of the magnetic core on the magnetic field generated by the brake coil, the magnetic field of the brake is strengthened. The influence of the electrical signals such as temperature detection and liquid level detection that already exist in the crystallizer is weakened or even eliminated, which greatly alleviates people's various concerns and worries about the electromagnetic flow control device that may exist, such as electromagnetic pollution, electromagnetic interference, etc., and is conducive to the promotion and application of electromagnetic braking technology in the production site.

[0067] In addition, the hydraulic cylinder works with high-pressure oil, which has a complex oil supply system and certain environmental issues. In order to further save the internal space of the crystallizer, the hydraulic cylinder can also be replaced by a large-thrust electric cylinder (or electric cylinder) with a smaller size, simpler operation and control, and more energy-saving and environmentally friendly, so as to better realize the real-time adjustment of the electromagnetic brake position and angle.

[0068] During slab continuous casting, after the molten steel comes out of the submerged water inlet 1 of the crystallizer, it first flows horizontally and obliquely downward, and hits the narrow surface 6 of the crystallizer to form upper and lower reflux zones. The upper reflux impacts the liquid surface, causing the meniscus 4 to fluctuate up and down. If the liquid surface fluctuates too much, it is easy to cause the protective slag to roll and form surface slag inclusions. The penetration depth of the lower reflux is too large, resulting in non-metallic inclusions not being easy to float up and staying inside the billet, eventually forming internal inclusions. In the horizontal flow area, the nozzle inclination angle θ is defined as the angle between the horizontal oblique jet 5 and the horizontal direction, generally θ = 5° ~ 30°, the speed V1 and angle θ of the horizontal oblique jet are affected by the design angle of the discharge holes 3 on both sides of the bottom of the nozzle, the billet drawing speed, and even the nozzle installation positioning inaccurate, the floating of the ceramic nozzle in the molten steel, the nozzle nodule and other practical factors, and may change at any time during the casting process, θ + α = 90°, therefore, the braking current I1 and the vertical angle α of the first brake should be dynamically adjusted according to the actual situation, so that the flow direction of the molten steel and the direction of the magnetic line of force are always in a vertical intersection state, so as to maximize the braking effect of the electromagnetic force on the flow of the molten steel, and even do not need to perform complex, troublesome and risky online adjustment or nozzle replacement operations on the nozzle as in the past. Specifically, the current intensity I1 of the first brake coil on the left side 11 The power supply 131 can be used to adjust the angle α1 between the left first brake and the vertical direction, and the left hydraulic cylinder 141 can be used to adjust the coil current intensity I of the right first brake. 12 The angle α2 between the first brake on the right and the vertical direction can be adjusted by the power supply 132. The angle α2 between the first brake on the right and the vertical direction can be adjusted by the hydraulic cylinder 142 on the right. In the lower reflow zone, due to the influence of the primary cooling of the crystallizer, the thickness of the solidified shell 7 increases as it goes downward, and the solid-liquid interface in the crystallizer is in a "V" shape. If the cooling conditions of the narrow copper plates 6 on both sides are asymmetric, the thickness of the solidified shell 7 is not equal. In addition, if the horizontal flow V1 is asymmetric on the left and right (i.e., V 11 ≠V 12 or α1≠α2), the velocity V2 of the molten steel flowing downward along the front edge of the solidification interface on the left and right sides and the angle β with the vertical direction must also be asymmetric and unequal, that is, V 21 ≠V 22 Or β1≠β2, resulting in different impact depths of the steel liquid streams on the left and right sides, causing uneven inclusions and mass distribution inside the final ingot, affecting the subsequent rolling process and the performance of the slab. Therefore, the current intensity I 21 The power supply 231 can be used to adjust the angle β1 between the left second brake and the vertical direction, and the left hydraulic cylinder 241 can be used to adjust the coil current intensity I 22The angle β2 between the second brake on the right and the vertical direction can be adjusted by the power supply 232. The angle β2 between the second brake on the right and the vertical direction can be adjusted by the hydraulic cylinder on the right 242. In the meniscus 4 area, since the free meniscus generally fluctuates horizontally up and down, and the liquid level height during different casting processes also changes frequently, the third brake is horizontally installed near the liquid level. Figure 4 , the installation position height (distance from the upper edge of the crystallizer) L p Online adjustment can be performed through the joint action of the left hydraulic cylinder 341 and the right hydraulic cylinder 342, and the coil current I3 can be adjusted through the power supply 330, which cooperates with the first electromagnetic brake and the second electromagnetic brake to achieve accurate, sufficient, timely and reasonable electromagnetic braking of liquid level fluctuations.

[0069] The slab continuous casting multi-zone composite electromagnetic braking device of the present invention aims at the shortcomings of the existing electromagnetic braking technology and solves a series of problems such as weak electromagnetic braking force of molten steel flow in the crystallizer, small action area, heavy equipment, inconvenient adjustment, high energy consumption, and limited effect. The purpose is to optimize the control of the flow state of molten steel in the crystallizer, reduce the excessive impact and disturbance of high-speed molten steel on the crystallizer molten pool, promote the full floating of inclusions in the molten steel, improve the cleanliness of molten steel, avoid defects such as inclusions, slag inclusions and even solidification hot cracking, and help to improve the slab continuous casting speed, surface quality and internal quality.

[0070] The present invention arranges a plurality of electromagnetic braking devices in different areas outside the wide surface of the crystallizer, adjusts and controls the intensity, angle and position of the electromagnetic braking online, adopts a high magnetic permeability composite structure magnetic core, and performs zoned, step-by-step, coordinated and composite electromagnetic braking on the entire process or the entire flow basin of molten steel in the crystallizer, thereby improving the electromagnetic braking effect, reducing the impact depth of molten steel streams and liquid level fluctuations, promoting the floating and absorption of inclusions in molten steel, improving the cleanliness of molten steel, reducing defects such as inclusions, slag inclusions and even cracks, and improving the quality and efficiency of slab production. The device has high electromagnetic efficiency, flexible adjustment, no (little) electromagnetic pollution, and is green, energy-saving, low-carbon and environmentally friendly, and is suitable for promotion and use in various high-speed continuous casting, thin slab continuous casting and other processes.

[0071] Example 1

[0072] In a high-speed continuous casting, for example, the billet drawing speed is 1.8 m / min, the flow state of molten steel on both sides of the nozzle is symmetrical, and the nozzle inclination angle θ = 15°, then: the first brake, through the hydraulic cylinders 141, 142, makes the first brake and the vertical direction include an angle α1 = α2 = 75°, through the power supply U 11 131.U 12 132 makes the braking current I 11 =I 12 =500A; the second brake, through the hydraulic cylinders 241, 242, makes the angle between the second brake and the vertical direction β1=β2=10°, through the power supply U 21231.U 22 232 makes the braking current I 21 =I 22 =400A; the third brake, through the hydraulic cylinders 341, 342 to make the third brake position height L p =250mm, and the braking current I3=300A ​​is made through the power supply U3330.

[0073] Example 2

[0074] There is an abnormality in a nozzle, for example, the flow state of molten steel on both sides of the nozzle is asymmetric. It is judged that θ1<θ2, V 11 <V 12 , V 21 <V 22 , then: the first brake, through the hydraulic cylinders 141, 142, makes the first brake and the vertical direction angle α1 = 80°, α2 = 70°, through the power supply U 11 131.U 12 132 makes the braking current I 11 =400A, I 12 =600A; the second brake, through the hydraulic cylinders 241, 242, makes the angle between the second brake and the vertical direction β1 = β2 = 10°, through the power supply U 21 231.U 22 232 makes the braking current I 21 =350A, I 22 =400A; the third brake, through the hydraulic cylinders 341, 342 to make the third brake position height L p =250mm, and the braking current I3=300A ​​is set through the power supply U3330, which appropriately reduces the braking effect on the left flow, or / and appropriately increases the braking effect on the right flow, so as to achieve the purpose of continuing casting without adjusting or replacing the water nozzle online.

[0075] Example 3

[0076] If the liquid level fluctuates abnormally, for example, the liquid level fluctuates too much, the liquid level detection reaches 20, 30 mm or even larger, the liquid level has a high tendency to roll slag, and the molten steel flows on the left and right sides are basically symmetrical, then: the first brake, through the hydraulic cylinders 141, 142, makes the first brake and the vertical direction angle α1=α2=75°, through the power supply U 11 131.U 12 132 makes the braking current I 11 =I 12 =500A; the second brake, through the hydraulic cylinders 241, 242, makes the second brake and the vertical direction angle β1 = β2 = 5°, through the power supply U 21 231.U 22 232 makes the braking current I 21=I 22 =400A; the third brake, through the hydraulic cylinders 341, 342 to make the third brake position height L p =200mm, and the braking current I3=500A is made through the power supply U3330. The electromagnetic suppression of liquid level fluctuation is strengthened by increasing the third electromagnetic braking current and raising the position of the third electromagnetic brake. In addition, the existence of the first electromagnetic brake and the second electromagnetic brake, especially the first electromagnetic brake, also slows down the flow rate of molten steel and reduces the impact and disturbance of the upper backflow on the free liquid surface to a certain extent. These combined effects effectively reduce the liquid level fluctuation and stabilize the continuous casting production and operation.

[0077] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A slab continuous casting multi-zone composite electromagnetic brake device, characterized in that: comprising a first electromagnetic brake, a second electromagnetic brake and a third electromagnetic brake; The first electromagnetic brake is arranged on the outside of the wide copper plate in the crystallizer, corresponding to the horizontal oblique jet of molten steel coming out of the submerged nozzle, and arranged in a horizontal oblique downward direction; The second electromagnetic brake is arranged on the outer side of the wide copper plate in the crystallizer and below the first electromagnetic brake, corresponding to the molten steel reflux, and symmetrically arranged on both sides of the center line of the crystallizer; The third electromagnetic brake is arranged on the outside of the wide copper plate in the crystallizer and above the first electromagnetic brake, corresponding to the upward reflux of molten steel and the fluctuation of liquid level, and is arranged in a horizontal direction to cover the width of the wide copper plate.

2. The slab continuous casting multi-zone composite electromagnetic brake device according to claim 1, characterized in that: The first electromagnetic brake comprises a left first electromagnetic brake mechanism and a right first electromagnetic brake mechanism respectively arranged on both sides of the vertical center line of the crystallizer; An included angle α between the symmetry center lines of the left first electromagnetic brake mechanism and the right first electromagnetic brake mechanism and the vertical center line of the crystallizer is 60° to 90°.

3. The slab continuous casting multi-zone composite electromagnetic brake device according to claim 2, characterized in that: The second electromagnetic brake comprises a left second electromagnetic brake mechanism and a right second electromagnetic brake mechanism respectively arranged on both sides of the vertical center line of the crystallizer; An included angle β between the symmetry center lines of the left second electromagnetic brake mechanism and the right second electromagnetic brake mechanism and the vertical center line of the crystallizer is 0° to 30°.

4. The slab continuous casting multi-zone composite electromagnetic brake device according to claim 3, characterized in that: The first left electromagnetic brake mechanism, the first right electromagnetic brake mechanism, the second left electromagnetic brake mechanism, and the second right electromagnetic brake mechanism all include a magnetic core, an electromagnetic coil, a power supply, and a hydraulic cylinder; The electromagnetic coil is wound around the magnetic core; The power supply is connected to the electromagnetic coil; The hydraulic cylinder adjusts the direction of the magnetic core to adjust the angle α and the angle β.

5. The slab continuous casting multi-zone composite electromagnetic brake device according to claim 3, characterized in that: The third electromagnetic brake comprises a magnetic core, an electromagnetic coil, a power supply, a left hydraulic cylinder and a right hydraulic cylinder; The magnetic core is horizontally arranged on the outer side of the wide copper plate; The electromagnetic coil is wound around the magnetic core; The power supply is connected to the electromagnetic coil; The left hydraulic cylinder is arranged at the left end of the magnetic core, and the right hydraulic cylinder is arranged at the right end of the magnetic core, so as to adjust the vertical distance L between the third brake and the upper edge of the crystallizer. p .

6. The slab continuous casting multi-zone composite electromagnetic brake device according to claim 4 or 5, characterized in that: The magnetic core comprises an inner core and a shell covering the outer surface of the inner core; The inner core is made of a high magnetic permeability material; The shell is made of electromagnetic pure iron.

7. The slab continuous casting multi-zone composite electromagnetic brake device according to claim 6, characterized in that: The high magnetic permeability material is a soft magnetic ferrite, which is composed of iron oxide and other compounds containing one or more elements of manganese, zinc, nickel and magnesium.

8. The slab continuous casting multi-zone composite electromagnetic brake device according to claim 7, characterized in that: The other compounds are oxides containing one or more elements among manganese, zinc, nickel and magnesium, or carbonate compounds containing one or more elements among manganese, zinc, nickel and magnesium.

9. The slab continuous casting multi-zone composite electromagnetic brake device according to claim 4, characterized in that: The hydraulic cylinder is an electric cylinder.

10. The slab continuous casting multi-zone composite electromagnetic brake device according to claim 5, characterized in that: The left hydraulic cylinder and the right hydraulic cylinder are electric cylinders.

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