A multi-zone composite electromagnetic braking device for slab continuous casting

Abstract

The application 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 the inner wide copper plate of a crystallizer, corresponds to the horizontal oblique jet flow of molten steel from a submerged nozzle and is arranged in a horizontal oblique downward direction; the second electromagnetic brake is arranged on the outer side of the inner wide copper plate of the crystallizer and is located below the first electromagnetic brake, corresponds to the downward return flow of molten steel and is symmetrically arranged on both sides of the center line of the crystallizer; and the third electromagnetic brake is arranged on the outer side of the inner wide copper plate of the crystallizer, is located above the first electromagnetic brake, corresponds to the upward return flow of molten steel and liquid surface fluctuation, is arranged in a horizontal direction and covers the width of the wide copper plate. The application solves a series of problems of the electromagnetic braking force of molten steel flow in the crystallizer, such as small action area, heavy equipment, inconvenient adjustment, high energy consumption and limited effect.

Description

TECHNICAL FIELD

[0001] The present application relates to slab continuous casting technology, more particularly, to a multi-zone composite electromagnetic braking device for slab continuous casting. BACKGROUND

[0002] High-grade automobile sheet, household appliance sheet, construction steel, electrical steel and the like have increasingly high requirements for the control of inclusions in steel. In the slab continuous casting process, the flow rate of molten steel flowing out of the submerged nozzle of the mould is often at the level of about 1 m / s, and the high-speed molten steel impacts the initial solidified shell of the narrow face of the mould, which on the one hand easily causes the initial shell to remelt and even causes a breakout accident, and on the other hand also promotes the solidification interface to capture inclusions to form steel defects in the solidified shell. After the molten steel flows out of the two side holes at the bottom of the submerged nozzle, it generally forms a "jet" that is inclined in a horizontally lower direction, and after colliding with the narrow face of the mould, it forms two large backflow zones, of which the upper backflow impacts the liquid surface to cause liquid surface fluctuation, which easily causes the covering of the protective slag on the surface of the molten steel to be rolled, and causes subsurface inclusions; the lower backflow has a greater penetration depth, often reaching several meters, which causes the non-metallic inclusions in the molten steel to flow to the deep part of the mould with the molten steel stream and be difficult to float, and finally forms internal inclusions. With the continuous increase of the modern continuous casting speed, this problem has a further deterioration trend. Therefore, how to reasonably control the flow field of the molten steel in the mould is the key to improving the quality and efficiency of slab continuous casting.

[0003] It has been proved that the electromagnetic brake EMBR (Electro Magnetic Brake) technology can slow down the flow rate of the molten steel in the crystallizer by inducing annular current through the interaction between the applied magnetic field and the flowing molten steel in the crystallizer, generating braking force opposite to the direction of the molten steel movement, so as to promote the full floating of the non-metallic oxide inclusions, protective slag, and stripped refractory material in the molten steel and adsorption on the protective slag layer on the top of the crystallizer pool, and finally removed, which is beneficial to improve the purity or cleanliness of the billet and avoid the occurrence of inclusions, slag inclusion, and hot cracking defects, and is an important tool indispensable for continuous casting of high-quality billets. In 1980, the first generation of regional type electromagnetic brake EMBR (+, -), i.e. local magnetic field electromagnetic brake technology, was jointly developed by ABB Company in Sweden and Kawasaki Steel Company in Japan, which can control the flow speed and direction of the molten steel flowing out of the submerged entry nozzle through the regional constant magnetic field arranged on the wide surface of the crystallizer and both sides of the submerged entry nozzle, reduce the scouring of the molten steel on the narrow surface billet shell, and inhibit the fluctuation of the liquid surface, thereby reducing the probability of slag entrapment and inclusion defects on the surface of the billet. However, due to the limited range of the magnetic field, there are problems such as insufficient braking effect, difficulty in inhibiting the fluctuation of the liquid surface, and inability to change the operating parameters. In 1991, the second generation of electromagnetic brake applying horizontal magnetic field covering the entire slab width was installed and experimented in Sollac Company in France and Hoogovens Company in the Netherlands, which is called EMBR Ruler or LMF (Level DC Magnetic Field) method. The horizontal magnetic field on the entire width of the crystallizer can obtain more stable electromagnetic braking effect and less sensitivity to different casting conditions. However, the electromagnetic brake device is greatly affected by the position. If the distance between the magnetic field position and the nozzle is slightly far or the angle of the nozzle outflow is slightly inappropriate, the braking effect will be affected, and even only the return flow is inhibited, and the fluctuation of the liquid surface is still not well controlled. The flow control crystallizer FC mold (Flow Control mold) is the third generation of electromagnetic brake device developed by Kawasaki Steel Company in Japan, which is composed of two horizontal magnetic fields covering the entire slab width, one of which is at the meniscus, and the other is oppositely applied below the submerged entry nozzle, which can simultaneously reduce the flow rate of the molten steel at the meniscus and the downward flow rate of the molten steel at the lower part of the crystallizer. Later, the FC mold II technology appeared, which can control the magnetic flux density of two sections through independent wiring and independent power supply, and the surface flow rate can be optimized through the control of the upper magnetic pole.

[0004] In the prior art, Japanese patent JP19870090634 fixes the electromagnet on the back plate at different positions by bolts, manually adjusts the position of the magnetic pole, and seeks the best electromagnetic braking effect area. Chinese patent CN97113854.0 divides the magnetic field of the electromagnetic brake into an upper magnetic field and a lower magnetic field to improve the calm state of the steel pool and reduce turbulence in the 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 provides a direct current electromagnetic coil and a hoof-shaped yoke above the crystallizer pool surface, slows down the impact of molten steel on the pool through left and right static magnetic fields, and suppresses pool fluctuations. Japanese patent JP20020067560 provides a magnetic pole and magnetic circuit design scheme for an electromagnetic braking device used in multi-stream continuous casting. International patent WO2002SE00030 arranges electromagnetic devices on the narrow edge of the crystallizer to electromagnetically brake the flow of molten steel near the narrow edge. Japanese patent JP20070298484 discloses an electromagnetic coil device that allows electromagnetic stirring or electromagnetic braking to selectively act on the molten steel. Chinese patent CN200980127917.5 symmetrically arranges at least two magnetic poles on the wide edge of the crystallizer and makes the magnetic poles form a certain angle (α1 or α2) with the median line. Chinese patent CN201610580291.5 relates to a vertical electromagnetic braking device arranged near the two side regions of the crystallizer to generate a stable braking magnetic field between the horizontal magnetic pole and the vertical magnetic pole.

[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, and the best can only reach 0.1-0.3T. Moreover, it mostly acts on the local area of the molten steel flow, and 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 electric energy is lost in Ohmic heat and cooling, and a lot of magnetic energy is lost in the structure space.

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

[0009] (4) The structure of the electromagnetic braking device is complex, and the weight is large due to the influence of the iron core. There are many difficulties or problems in installing it on the traditional vibrating crystallizer.

[0010] (5) The demand for energy sources such as power supply and cooling water is high due to the low conversion efficiency of the device.

[0011] Therefore, it is urgent to develop high-quality, efficient and low-consumption continuous casting technology, especially new electromagnetic braking technology for controlling and optimizing the flow state of molten steel in the crystallizer by electromagnetic field to further improve the continuous casting quality and efficiency, which has significant economic and social benefits, especially in today's emphasis on "green" and "low-carbon" development. SUMMARY

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

[0013] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

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

[0015] The first electromagnetic brake is arranged on the outer side of the wide copper plate in the crystallizer, corresponds to the horizontal oblique jet flow of the molten steel out of the submerged nozzle, and is arranged in a horizontal downward direction.

[0016] The second electromagnetic brake is arranged on the outer side of the wide copper plate in the crystallizer and is located below the first electromagnetic brake, corresponds to the downward flow of the molten steel, and is symmetrically arranged on both sides of the center line of the crystallizer.

[0017] The third electromagnetic brake is arranged on the outer side of the wide copper plate in the crystallizer and is located above the first electromagnetic brake, corresponds to the upward flow of the molten steel and the liquid level fluctuation, and is arranged in a horizontal direction covering 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 arranged on both sides of the vertical center line of the crystallizer, respectively.

[0019] The angle a between the symmetric center line of the left first electromagnetic brake mechanism and the right first electromagnetic brake mechanism and the vertical center line of the crystallizer is 60°-90°.

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

[0021] The angle β between the symmetric center line of the left second electromagnetic brake mechanism and the right second electromagnetic brake mechanism and the vertical center line of the crystallizer is 0°-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 each comprise a magnetic core, an electromagnetic coil, a power supply and a hydraulic cylinder.

[0023] The electromagnetic coil is wound on the magnetic core.

[0024] The power supply is connected with the electromagnetic coil.

[0025] The hydraulic cylinder adjusts the direction of the magnetic core to adjust the included angle α and the included 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 outside the wide copper plate.

[0028] The electromagnetic coil is wound on the magnetic core.

[0029] The power supply is connected with 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 an outer shell wrapped outside the outer surface of the inner core.

[0032] The inner core is made of high permeability material.

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

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

[0035] Preferably, the other compounds are oxides containing one or more of manganese, zinc, nickel and magnesium, or carbonate compounds containing one or more 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 brake device provided by the application has the following advantages:

[0039] 1) Compared with the traditional electromagnetic braking technology, the slab continuous casting multi-zone composite electromagnetic braking device has a large acting range, high electromagnetic conversion efficiency and 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 has light weight, strong adjustment capacity, low energy consumption and flexible and convenient use;

[0041] 3) Compared with the traditional electromagnetic braking technology, the slab continuous casting multi-zone composite electromagnetic braking device performs step-by-step and composite electromagnetic braking in the whole flow area of the molten steel in the crystallizer, the molten steel purification effect is more obvious, and defects such as inclusions, slag inclusions and hot cracking (cracks often occur and expand at inclusions) are avoided, thereby improving the continuous casting quality and efficiency. BRIEF DESCRIPTION OF DRAWINGS

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

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

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

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

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

[0047] In order to better understand the above technical solutions of the present application, the technical solutions of the present application will be further described below in combination with the drawings and examples.

[0048] As shown in Figure 1 and Figure 2 , the slab continuous casting multi-zone composite electromagnetic braking device provided by the present application matches the main flow path of the molten steel in the crystallizer, and along the molten steel flow direction, three electromagnetic brakes are arranged in the whole molten steel flow area, including a first electromagnetic brake, a second electromagnetic brake and a third electromagnetic brake.

[0049] The first electromagnetic brake is arranged outside the position of the wide face copper plate 2 in the crystallizer, corresponds to the horizontal oblique jet flow V1 (the angle with the vertical direction is α) out of the submerged lance 1, and is arranged in a horizontally downward direction.

[0050] The second electromagnetic brake is arranged outside the position of the wide copper plate 2 in the crystallizer, is below the first electromagnetic brake, corresponds to the downward flow V2 of the molten steel in the crystallizer (the angle with the vertical direction is β), and is arranged in a vertical and inclined 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, is above the first electromagnetic brake, corresponds to the upward flow V3 of the molten steel in the crystallizer and the fluctuation of the liquid surface, 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 to control the flow of the molten steel according to the actual situation, the purpose of effectively reducing the impact depth of the molten steel stock flow, inhibiting the fluctuation of the meniscus liquid level, and avoiding the occurrence of quality defects such as inclusions, slag entrapment, and cracks is achieved.

[0053] The braking magnetic field of each stage of electromagnetic brake, as shown in Figure 2 , the magnetic lines are from one side of the wide copper plate 2 of the crystallizer to the other side of the wide copper plate 2 of the crystallizer. As shown in Figure 3 , 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., to form multiple, independent, closed magnetic field loops; each braking magnetic field is a static magnetic field generated by passing direct current in the electromagnetic coil, and the size of the direct current or the magnetic field strength can be individually adjusted by the respective power supply; the installation position and angle of each electromagnetic brake can be adjusted online by the action of the hydraulic cylinder.

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

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

[0056] The left first electromagnetic brake mechanism is composed of an electromagnetic coil 111, a magnetic core 121, and a power supply 131, and the size of the direct current output by the power supply 131 can be adjusted. The magnetic core 121 is wound with the electromagnetic coil 111 outside, and the assembly of the magnetic core 121 and the electromagnetic coil 111 can adjust the angle size of the angle α1 through the 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 direct current outputted by the power supply 132 can be adjusted, the electromagnetic coil 112 is wound outside the magnetic core 122, and the assembly of the magnetic core 122 and the electromagnetic coil 112 can adjust the angle size of the included angle α2 through a hydraulic cylinder 142.

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

[0059] The jet flow velocities at the left second electromagnetic brake mechanism and the right second electromagnetic brake mechanism are V 21 and V 22 respectively, the included angles 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 are β1 and β2 respectively, and the angles of the included angles β1 and β2 are 0°-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 direct current outputted by the power supply 231 can be adjusted, the electromagnetic coil 211 is wound outside the magnetic core 221, and the assembly of the magnetic core 221 and the electromagnetic coil 211 can adjust the angle size of the included 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 direct current outputted by the power supply 232 can be adjusted, the electromagnetic coil 212 is wound outside the magnetic core 222, and the assembly of the magnetic core 222 and the electromagnetic coil 212 can adjust the angle size of the included angle β2 through a hydraulic cylinder 242.

[0062] The third electromagnetic brake corresponds to the upper return flow V3 and the liquid level fluctuation, is composed of an electromagnetic coil 310, a magnetic core 320 and a power supply 330, the direct current outputted by the power supply 330 can be adjusted, and the assembly of the magnetic core 320 and the electromagnetic coil 310 can adjust the size of the distance from the upper edge of the crystallizer, i.e. the vertical position L p .

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

[0064] The high-permeability material is soft magnetic ferrite, which is composed of iron oxide (Fe2O3) and other compounds containing one or several elements of manganese, zinc, nickel and magnesium. The ferrite raw material is processed into a magnetic core for electromagnetic brake through pressing, sintering, processing and assembling.

[0065] The other compound is an oxide containing one or several elements of manganese, zinc, nickel and magnesium or a carbonate compound containing one or several elements of manganese, zinc, nickel and magnesium.

[0066] The ferrite has high permeability and small specific gravity. Generally, the relative permeability of soft magnetic ferrite is mr=10000-30000, and the density is r=4.8-4.9×10 3 kg / m 3 The relative permeability of electromagnetic pure iron is mr=200-400, and the density is r=7.8×10 3 kg / m 3 Due to the improved magnetic permeability of the magnetic core, the electromagnetic conversion efficiency and the magnetic field strength of the electromagnetic brake can be improved by more than 30-50%, which significantly improves the effect of the electromagnetic brake. Due to the reduced specific gravity of the magnetic core, the weight of the brake device can be reduced by more than 30-50%, which helps the installation and fixation of the electromagnetic brake on the back plate of the crystallizer and reduces the load of the crystallizer vibration mechanism. Due to the use of high-permeability material for the magnetic core, the cross-sectional size of the magnetic core can be reduced by 30-50% under the condition of the same magnetic flux, which is beneficial to the design and arrangement of the electromagnetic brake in the limited space inside the crystallizer. At the same time, due to the enhanced gathering, restraining and shielding effect of the magnetic core with high permeability on the magnetic field generated by the brake coil, the influence of the brake magnetic field on the existing electrical signals such as temperature detection and liquid level detection in the crystallizer is weakened or even eliminated, which greatly alleviates the concerns and worries about the possible problems such as electromagnetic pollution and electromagnetic interference of the electromagnetic control flow device, and is beneficial to the promotion and application of the electromagnetic brake technology in the production site.

[0067] In addition, the hydraulic cylinder works through high-pressure oil, and the oil supply system is relatively complex and has certain environmental problems. In order to further save the internal space of the crystallizer, a large-thrust electric cylinder (or electric cylinder) with smaller size, simpler operation control and better energy saving and environmental protection can be considered to replace the hydraulic cylinder, so as to better realize real-time adjustment of the electromagnetic brake position and angle.

[0068] In slab continuous casting, after the molten steel comes out of the immersion nozzle 1 of the crystallizer, it first flows horizontally downwards. When it encounters the narrow face 6 of the crystallizer, it forms upper and lower reflux zones. The upper reflux impacts the liquid surface, causing the meniscus 4 to fluctuate up and down. Excessive fluctuation of the liquid surface can easily cause the protective slag to be rolled up, forming surface inclusions. If the lower reflux penetrates too deeply, non-metallic inclusions will not easily float to the surface and will remain inside the steel billet, eventually forming internal inclusions. In the horizontal flow region, the nozzle inclination angle θ is defined as the angle between the horizontal oblique jet 5 and the horizontal direction, generally θ = 5° to 30°. The velocity V1 and angle θ of the horizontal oblique jet are affected by various practical factors such as the design angle of the discharge holes 3 on both sides of the nozzle bottom, the billet pulling speed, and even inaccurate nozzle installation and positioning, the floating of ceramic nozzles in molten steel, and nozzle nodules. These factors may change at any time during the casting process. θ + α = 90°. Therefore, the braking current I1 of the first brake and the vertical angle α should be dynamically adjusted according to the actual situation to ensure that the direction of molten steel flow and the direction of magnetic lines of force are always perpendicular to each other, so as to maximize the braking effect of electromagnetic force on the flow of molten steel. It is even possible to avoid the complex, troublesome, and risky online adjustment or nozzle replacement work that was often required when this situation occurred before. Specifically, the current intensity I of the first brake coil on the left side is... 11 The angle α1 between the left first brake and the vertical direction can be adjusted via power supply 131, and the angle α1 between the left first brake and the vertical direction can be adjusted via the left hydraulic cylinder 141. The coil current intensity I of the right first brake... 12 The angle α2 between the right-side first brake and the vertical direction can be adjusted via power supply 132, and via right-side hydraulic cylinder 142. In the lower recirculation zone, due to the influence of the primary cooling effect of the crystallizer, the thickness of the solidified shell 7 increases further downwards, and the solid-liquid interface shape inside the crystallizer is "V". If the cooling conditions of the narrow copper plates 6 on both sides are asymmetrical, the thickness of the solidified shell 7 will be unequal. Furthermore, if the horizontal flow V1 is asymmetrical on the left and right (i.e., V... 11 ≠V 12 Or α1≠α2), the magnitude of the velocity V2 of the molten steel flowing downwards 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 asymmetrical and unequal, that is, V 21 ≠V 22 If β1≠β2, the impact depth of the molten steel streams on the left and right sides will be different, resulting in uneven distribution of inclusions and mass inside the final cast slab. This will affect the subsequent rolling process and the performance of the slab. Therefore, the current intensity I of the second brake coil on the left side... 21 The angle β1 between the left second brake and the vertical direction can be adjusted via power supply 231, and the coil current intensity I of the right second brake can be adjusted via the left hydraulic cylinder 241. 22The right second brake angle with the vertical direction β2 can be adjusted by the right hydraulic cylinder 242. In the region of the meniscus 4, due to the free meniscus generally in the horizontal up and down fluctuation state, and the liquid level height in different casting process is also frequently changed, therefore, the third brake is horizontally installed near the liquid surface position, referring to Figure 4 The installation position height (distance from the upper edge of the crystallizer) L p The coil current I3 can be adjusted by the power supply 330, and the first electromagnetic brake and the second electromagnetic brake are cooperated to realize accurate, sufficient, timely and reasonable electromagnetic braking for the liquid surface fluctuation.

[0069] The slab continuous casting multi-region composite electromagnetic brake device aims at the deficiencies of the existing electromagnetic brake technology, solves the problems of weak electromagnetic braking force, small action area, heavy equipment, inconvenient adjustment, high energy consumption and limited effect of the molten steel flow in the crystallizer, optimizes the control of the molten steel flow in the crystallizer, slows down the excessive impact and disturbance of the high-speed molten steel on the crystallizer pool, promotes the sufficient floating of inclusions in the molten steel, improves the cleanliness of the molten steel, avoids the defects of inclusions, slag inclusion and even solidification hot cracking, and helps to improve the slab continuous casting speed, surface quality and internal quality.

[0070] The present application sets multiple electromagnetic brake devices in different regions outside the wide surface of the crystallizer, adjusts and controls the strength, angle and position of the electromagnetic brake online, adopts a high-permeability composite structure magnetic core, performs partition, step-by-step, cooperative and composite electromagnetic braking on the whole process or whole flow area of the molten steel flow in the crystallizer, improves the electromagnetic braking effect, reduces the impact depth of the molten steel flow and the liquid surface fluctuation, promotes the floating and absorption of inclusions in the molten steel, improves the cleanliness of the molten steel, reduces the defects of inclusions, slag inclusion and even cracks, improves the slab production quality and efficiency, the device has high electromagnetic efficiency, flexible adjustment, no electromagnetic pollution, and is green, energy-saving, low-carbon and environmentally friendly, and is suitable for popularization and use in various high-speed continuous casting and thin slab continuous casting processes.

[0071] Example 1

[0072] In a certain high-speed continuous casting, for example, the casting speed is 1.8 m / min, the molten steel flow state on both sides of the nozzle is symmetrical, the nozzle inclination angle θ = 15°, then: the first brake, the first brake angle with the vertical direction α1 = α2 = 75° is adjusted by the hydraulic cylinders 141 and 142, the brake current I 11 131, U 12 132 makes the brake current I 11 = I 12 = 500 A; the second brake, the second brake angle with the vertical direction β1 = β2 = 10° is adjusted by the hydraulic cylinders 241 and 242, the brake current I 21231、U 22 232 make braking current I 21 = I 22 = 400 A; third brake, through hydraulic cylinder 341, 342 make third brake position height L p = 250 mm, through power supply U3 330 make braking current I3 = 300 A.

[0073] Example 2

[0074] If some water gap is abnormal, for example, the flow state of molten steel on both sides of the water gap is asymmetric, and it is judged that θ1 < θ2, V 11 < V 12 , V 21 < V 22 , then: the first brake, through hydraulic cylinder 141, 142 make the first brake angle α1 = 80°, α2 = 70° with the vertical direction, through power supply U 11 131, U 12 132 make braking current I 11 = 400 A, I 12 = 600 A; the second brake, through hydraulic cylinder 241, 242 make the second brake angle β1 = β2 = 10° with the vertical direction, through power supply U 21 231, U 22 232 make braking current I 21 = 350 A, I 22 = 400 A; the third brake, through hydraulic cylinder 341, 342 make the third brake position height L p = 250 mm, through power supply U3 330 make braking current I3 = 300 A, appropriately reduce the braking effect on the left flow, or / and, appropriately increase the braking effect on the right flow, which can achieve the purpose of continuing casting without online adjustment or replacing the water gap.

[0075] Example 3

[0076] If some liquid level fluctuation is abnormal, for example, the liquid level fluctuation is too large, the liquid level detection reaches 20, 30 mm or even larger, the liquid level slag entrapment tendency is high, and the molten steel flow on both left and right sides is basically symmetric, then: the first brake, through hydraulic cylinder 141, 142 make the first brake angle α1 = α2 = 75° with the vertical direction, through power supply U 11 131, U 12 132 make braking current I 11 = I 12 = 500 A; the second brake, through hydraulic cylinder 241, 242 make the second brake angle β1 = β2 = 5° with the vertical direction, through power supply U 21 231, U 22 232 make braking current I 21= I 22 = 400 A; the third brake is located at a height L p = 200 mm, the brake current I3= 500 A is generated by the power supply U3 330, the electromagnetic suppression of the liquid surface fluctuation is strengthened by increasing the third electromagnetic brake 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 speed of the molten steel to a certain extent and reduces the impact and disturbance of the upward flow on the free liquid surface, and these combined effects effectively reduce the liquid surface fluctuation and stabilize the continuous casting production and operation.

[0077] Those skilled in the art of the present technology should recognize that the above embodiments are only used to illustrate the present application, and are not used as a limitation of the present application, as long as the changes and modifications of the above described embodiments are within the scope of the spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A slab continuous casting multi-zone composite electromagnetic braking device, characterized by: The first electromagnetic brake, the second electromagnetic brake and the third electromagnetic brake are arranged on the outer side of the copper plate of the inner width of the crystallizer. The first electromagnetic brake is arranged in a horizontal and downward direction corresponding to the horizontal and oblique jet flow of the molten steel from the submerged nozzle. The second electromagnetic brake is arranged on the outer side of the copper plate of the inner width of the crystallizer and below the first electromagnetic brake, corresponding to the downward flow of the molten steel and symmetrically arranged on both sides of the center line of the crystallizer. The third electromagnetic brake is arranged on the outer side of the copper plate of the inner width of the crystallizer and above the first electromagnetic brake, corresponding to the upward flow of the molten steel and the liquid surface fluctuation, and arranged in a horizontal direction covering the width of the copper plate. The first electromagnetic brake includes a left first electromagnetic brake mechanism and a right first electromagnetic brake mechanism arranged on both sides of the vertical center line of the crystallizer. The angle α between the symmetric center line of the left first electromagnetic brake mechanism, the symmetric center line of the right first electromagnetic brake mechanism and the vertical center line of the crystallizer is 60°-90°. The second electromagnetic brake includes a left second electromagnetic brake mechanism and a right second electromagnetic brake mechanism arranged on both sides of the vertical center line of the crystallizer. The angle β between the symmetric center line of the left second electromagnetic brake mechanism, the symmetric center line of the right second electromagnetic brake mechanism and the vertical center line of the crystallizer is 5°-30°. 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. The electromagnetic coil is wound on 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 angles of the angles α and β.

2. The slab continuous casting multi-zone composite electromagnetic braking device according to claim 1, characterized in that: The third electromagnetic brake includes 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 copper plate of the inner width. The electromagnetic coil is wound on 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 electromagnetic brake and the upper edge of the crystallizer p .

3. The slab continuous casting multi-zone composite electromagnetic braking device according to claim 1 or 2, characterized in that: The magnetic core includes an inner core and an outer shell wrapped on the outer surface of the inner core. The inner core is made of high permeability material. The outer shell is made of electromagnetic pure iron.

4. The slab continuous casting multi-zone composite electromagnetic braking device according to claim 3, characterized in that: The high permeability material is soft magnetic ferrite, which is composed of iron oxide and other compounds containing one or more of manganese, zinc, nickel and magnesium. The other compounds are oxides containing one or more of manganese, zinc, nickel and magnesium or carbonate compounds containing one or more of manganese, zinc, nickel and magnesium.

5. The slab continuous casting multi-zone composite electromagnetic braking device according to claim 1, characterized in that: The hydraulic cylinder is an electric cylinder.

6. The slab continuous casting multi-zone composite electromagnetic braking device according to claim 2, characterized in that: The left hydraulic cylinder and the right hydraulic cylinder are electric cylinders.

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