Roller-type electromagnetic stirring device and method with braking function

Abstract

The present invention discloses a roller-type electromagnetic stirring device and method with a braking function. The roller-type electromagnetic stirring device comprises a traveling roller, a brake roller, and a connecting base. The two ends of the brake roller are connected to the first end of the traveling roller via the connecting base. The traveling roller comprises an iron core, a traveling coil, and a roller sleeve. The traveling coil is wound around the iron core and generates a traveling magnetic field when energized. The brake roller comprises an outer cylinder, an iron core, an arc-shaped enclosure, and an end cap. The ends of the arc-shaped enclosure are sealed to the end cap to form a hollow cylinder. The iron core is fixedly mounted within the hollow cylinder and perpendicular to the outer cylinder. The iron core has a waist-shaped cross-section and is wound around the iron core. The brake coil generates a braking magnetic field perpendicular to the traveling magnetic field when energized. The traveling roller generates a lateral thrust to stir the unsolidified liquid core within the ingot. The brake roller generates a longitudinal braking force to buffer the combined impact of the molten steel circulation caused by the lateral thrust of the two traveling rollers, promoting thorough mixing of the molten steel, floating inclusions, and preventing slag entrainment.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgical equipment and electromagnetic stirring, and in particular to a roller-type electromagnetic stirring device and method with a braking function. Background Art

[0002] Thin slab continuous casting and rolling technology has been promoted and applied worldwide due to its advantages such as a short process flow, short production cycle, low energy consumption, high yield rate, and uniform performance. During the thin slab continuous casting process, problems such as corrugated defects on the slab surface and low continuous casting efficiency often occur. Continuous casting practice has shown that if the equiaxed grain rate of the slab can be increased to above 45%, the corrugated defects can be basically eliminated. However, conventional processes such as reducing the casting superheat, weakening the cooling, changing the phase change range of the rolled steel during rolling, or adding manganese components, etc., are difficult to effectively increase the equiaxed grain rate of the slab to achieve the purpose of improving corrugated defects. Moreover, the addition of alloy components increases production costs and lacks a competitive advantage.

[0003] In recent years, installing roller electromagnetic stirring in the second cooling roller array in the casting zone, especially using roller electromagnetic stirring with a traveling wave magnetic field that can generate transverse electromagnetic thrust to suppress the growth of columnar crystals in slab continuous casting and solve corrugated defects has become a focus of attention at home and abroad, and has been applied to varying degrees in the continuous casting production of steel grades with a large tendency to solidify columnar crystals, such as stainless steel and silicon steel.

[0004] However, in thin slab continuous casting, it is difficult to play a stirring role using conventional roller electromagnetic stirring technology. However, the thin slab continuous casting machine has a short process, fast casting speed, and short solidification end point. Therefore, in order for the electromagnetic roller to play a stirring role, the installation position must be at the front of the secondary cooling zone, such as Figure 1 As shown, the rollers 8 for providing electromagnetic stirring need to be installed close to the crystallizer 7. Only then will there be enough unsolidified liquid core in the billet 5 to be stirred and flowed by the magnetic field generated by the rollers 8. However, the rollers 8 are installed too far forward in the secondary cooling zone. The lateral electromagnetic thrust they generate causes rapid and large circulation of the molten steel, which can easily cause liquid level fluctuations below the crystallizer 7 and deflection of the cross-section of the billet, resulting in more serious billet quality problems such as slag coiling and liquid level fluctuations.

[0005] Patent CN108500228B discloses a method for controlling the flow field of a slab continuous casting mold. This method uses an electromagnetic stirring device and an electromagnetic braking device to control the flow field of the slab continuous casting mold. Electromagnetic stirring devices are located in the upper regions on both sides of the mold's wide surface, while electromagnetic braking devices are located in the lower regions on both sides of the mold's wide surface. The upper and lower electromagnetic braking devices are independent and separately arranged. The upper electromagnetic stirring device stirs the molten steel, and the lower electromagnetic braking device adjusts and controls the circulation velocity of the stirring, thereby adjusting and controlling the flow velocity of the molten steel. However, the electromagnetic stirring and braking devices in this structure are separately arranged, resulting in limited braking effect. Furthermore, this structure requires more installation space, making retrofitting into existing equipment difficult.

[0006] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art. Summary of the Invention

[0007] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a roller-type electromagnetic stirring device with a braking function. A brake roller is arranged between two waving rollers. The waving roller generates a lateral thrust to stir the unsolidified liquid core in the ingot. The brake roller located in the middle generates a longitudinal braking force to buffer the larger lateral thrust generated by the superposition of the waving rollers on both sides, thereby avoiding large or too fast circulation of molten steel to disturb the liquid surface at the crystallizer and prevent slag rolling.

[0008] In order to achieve the above-mentioned object, the present invention provides a roller-type electromagnetic stirring device with a braking function, comprising a traveling roller, a brake roller and a connecting seat, wherein both ends of the traveling roller are rotatably connected to the connecting seat, and both ends of the brake roller are respectively fixedly connected to the connecting seat at the first end of the traveling roller;

[0009] The traveling wave roller includes a traveling wave roller core, a traveling wave coil and a roller sleeve. The traveling wave coil is wound on the traveling wave roller core. The roller sleeve is sleeved on the outside of the traveling wave coil to seal the traveling wave coil. The traveling wave roller core is fixedly connected to the connecting seat. The roller sleeve is rotatably connected to the connecting seat. When the traveling wave coil is energized, a traveling wave magnetic field is generated.

[0010] The brake roller includes an outer cylinder, an arc-shaped enclosure, a brake roller core and an end cover. The two ends of the outer cylinder are respectively fixedly connected to the connecting seats at the first ends of the two traveling wave rollers. The arc-shaped enclosure is semicircular. The two arc-shaped enclosures are sealed and connected to form a hollow cylinder. The two ends of the arc-shaped enclosure are respectively sealed and connected to the end covers. A gap is left between the outer surface of the hollow cylinder and the inner surface of the outer cylinder. The brake roller core is fixedly installed in the hollow cylinder and is perpendicular to the axial direction of the outer cylinder. The cross-section of the brake roller core is waist-shaped. A brake coil is wound on the brake roller core. When the brake coil is energized, a braking magnetic field perpendicular to the traveling wave magnetic field is generated.

[0011] Furthermore, the brake roller further includes an insulating baffle, the inner surface of the arc-shaped enclosure plate is inscribed in the insulating baffle, and the insulating baffle is sleeved on the outer surface of the brake coil.

[0012] Furthermore, the brake roller also includes a threaded connecting rod, and one end of the brake roller iron core is provided with a threaded hole corresponding to the threaded connecting rod. The arc-shaped enclosure and the insulating baffle located at one end of the threaded hole of the brake roller iron core are both provided with through holes. The first end of the threaded connecting rod passes through the through holes on the arc-shaped enclosure and the insulating baffle and is threadedly connected to the threaded hole of the brake roller iron core, and the threaded connecting rod is threadedly connected to the nut from the second end.

[0013] Furthermore, a countersunk hole is provided on the outer periphery of the through hole of the arc-shaped enclosure plate, and a waterproof coating is filled in the countersunk hole. A clamping groove is provided on the inner surface of the outer cylinder, and a special-shaped key is clamped in the clamping groove. A V-shaped groove is provided at one end of the special-shaped key, and the second end of the threaded connecting rod is clamped in the V-shaped groove (211).

[0014] Furthermore, a threading hole is provided on the threaded connecting rod, and both ends of the brake coil are led out to the gap between the outer cylinder and the arc-shaped enclosure through the threading hole, and the threading hole is filled with waterproof material for sealing.

[0015] Furthermore, a circular groove corresponding to the arc-shaped enclosure plate is opened on the inner side of the end cover, an O-ring is installed in the circular groove, and both ends of the arc-shaped enclosure plate are respectively clamped in the circular groove.

[0016] Furthermore, the length of the brake roller is 1 / 3 to 2 / 3 of the length of the traveling roller.

[0017] Furthermore, the connecting seat includes a bearing seat, a bearing is nested and installed in the bearing seat, the open end of the bearing seat is sealed and connected to the bearing cover, the diameters at both ends of the traveling wave roller iron core are smaller than the middle diameter, the two ends of the traveling wave roller iron core are respectively fixedly connected to the bearing cover, and a mechanical sealing device is provided at the small diameters at both ends of the traveling wave roller iron core, and the roller sleeve is connected to the bearing through the mechanical sealing device.

[0018] Furthermore, an outlet box is fixedly connected to a connecting seat on the end of the traveling wave roller away from the brake roller, and a cooling water pipe connector and a power supply connector are provided in the outlet box. The cooling water pipe connector is connected to the roller sleeve to cool the traveling wave coil, and the traveling wave coil is connected to an external power supply through the power supply connector.

[0019] Based on a general inventive concept, the present invention also provides a method for using a roller-type electromagnetic stirring device with a braking function, wherein the roller-type electromagnetic stirring devices with a braking function are installed in pairs in the secondary cooling zone of the ingot, and any pair of the roller-type electromagnetic stirring devices with a braking function are symmetrically installed near the upper and lower surfaces of the ingot, and at least two pairs of the roller-type electromagnetic stirring devices with a braking function are arranged in the secondary cooling zone, wherein at least one pair of the roller-type electromagnetic stirring devices with a braking function are arranged at one end close to the crystallizer, and at the same time, at least one pair of the roller-type electromagnetic stirring devices with a braking function are arranged at one end away from the crystallizer.

[0020] The above solution of the present invention has the following beneficial effects:

[0021] The roller-type electromagnetic stirring device with braking function provided by the present invention adopts the method of separating the conventional electromagnetic stirring rollers at both ends and arranging a brake roller in the middle of the two waving rollers. The waving rollers at both ends respectively generate transverse electromagnetic forces parallel to the wide surface of the ingot, thereby promoting the stirring of the unsolidified liquid core in the second cooling zone of the ingot to form two small circulations. The two small circulations will be superimposed in the middle of the wide surface of the ingot, resulting in too fast a circulation speed in the middle; at this time, the brake roller located in the middle will generate a longitudinal electromagnetic force parallel to the wide surface of the ingot, which can produce a deceleration and braking effect on the excessively fast circulation speed of the liquid core in the middle of the wide surface of the ingot, and control the circulation speed in the middle within an appropriate range. On the one hand, it avoids the flow drum impacting too deeply, causing disturbance of the liquid surface at the crystallizer, and prevents serious quality problems such as slag rolling. This also provides a guarantee for the electromagnetic stirring roller to be installed close to the crystallizer. The closer the electromagnetic roller is to the crystallizer, the earlier the high-temperature molten steel coming out of the crystallizer can be dissipated, preventing the formation of columnar crystals.

[0022] The surface of the continuous casting ingot is sprayed with cooling water, and the ingot surface is in contact with air, which facilitates heat dissipation. However, if the temperature of the unsolidified molten steel in the center of the ingot is not controlled by electromagnetic flow to force the hot molten steel to flow near the surface, it will only be transferred from the inside to the outer surface through heat conduction, and the heat transfer rate is very slow. As a result, the molten steel originally flowing through the electromagnetic stirring roller near the crystallizer stops exchanging heat with the outer surface after exceeding the flow control range of the electromagnetic stirring roller. This causes the core temperature to be much higher than the surface, forming a large temperature gradient and generating secondary columnar crystals. Therefore, it is necessary to add electromagnetic stirring rods far away from the crystallizer (≤2 meters). The electromagnetic stirring rods at the near and far ends of the crystallizer will overlap in the middle to form two closed circulations. The circulation speed near the middle will be further increased. At this time, the brake roller provides a braking force perpendicular to the ingot, which can disperse the concentrated intermediate circulation, enhance the uniform distribution of components and heat in the molten steel, and prevent slag inclusions from being too deep to be removed, causing serious quality problems.

[0023] The present invention creatively combines the brake roller structure with the conventional electromagnetic roller, which has great advantages in effectively controlling the circulation speed of the liquid core of the casting, heat dissipation uniformity, liquid surface disturbance control, etc. Moreover, the roller-type electromagnetic stirring device with a braking function of the present invention is basically consistent with the size and shape of the conventional electromagnetic stirring roller, which is convenient for direct upgrading and transformation of existing continuous casting production equipment.

[0024] Other beneficial effects of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of electromagnetic stirring in the secondary cooling zone of the slab in the prior art;

[0026] Figure 2 This is a schematic diagram of the installation of a roller-type electromagnetic stirring device with a braking function according to the present invention;

[0027] Figure 3 This is a cross-sectional view of the overall structure of the roller-type electromagnetic stirring device with a braking function of the present invention;

[0028] Figure 4 This is a schematic diagram of the internal structure of the brake roller of the present invention;

[0029] Figure 5 This is an exploded view of the internal structure of the brake roller of the present invention;

[0030] Figure 6 This is a schematic structural diagram of the outer cylinder of the brake roller of the present invention;

[0031] Figure 7 This is a schematic diagram of the special-shaped key structure of the brake roller of the present invention;

[0032] Figure 8 This is a schematic diagram of the structure of the arc-shaped enclosure plate of the brake roller of the present invention;

[0033] Figure 9 This is a schematic structural diagram of the threaded connecting rod of the brake roller of the present invention;

[0034] Figure 10 This is a side view of the roller-type electromagnetic stirring device with a braking function of the present invention when it is installed and used;

[0035] Figure 11 Schematic diagram of the circulation of molten steel stirred by the roller-type electromagnetic stirring device of the present invention;

[0036] Figure 12 for Figure 11 Cross-sectional view along the cc direction (schematic diagram of electromagnetic force);

[0037] Figure 13 for Figure 12 Side view of the structure (electromagnetic force schematic).

[0038] [Description of Reference Numerals]

[0039] 1-Wave roller; 11-Wave roller core; 12-Wave coil; 13-Roller sleeve; 2-Brake roller; 20-Outer cylinder; 201-Card slot; 21-Special-shaped key; 211-V-groove; 22-Nut; 23-Threaded connecting rod; 24-Waterproof coating; 25-Curved enclosure; 26-Insulating enclosure; 27-Brake roller core; 28-End cover; 29-O-ring; 3-Connecting seat; 31-Bearing seat; 32-Bearing; 33-Bearing cover; 4-Outlet box; 5-Casting billet; 6-Sprue; 7-Crystallizer; 8-Through roller; A-Roller stirring device with braking function; B-Clamping roller. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The various specific technical features and embodiments described in the specific embodiments can be combined in any suitable manner unless there is any contradiction. For example, different embodiments can be formed by combining different specific technical features / embodiments. In order to avoid unnecessary repetition, the various possible combinations of the various specific technical features / embodiments in the present invention will not be described separately.

[0041] It should be noted that the terms "setting" and "connecting" should be understood in a broad sense. For example, they can be directly set, installed, or connected, or they can be indirectly set or connected through a central component or a central structural part. In addition, the orientations or positional relationships indicated by "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. in the present invention are based on the orientations or positional relationships shown in the drawings or the conventional placement state or usage state. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the structural parts, features, devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the present invention.

[0042] Example 1

[0043] like Figures 2 to 9 As shown, the present invention provides a roller-type electromagnetic stirring device with a braking function, comprising a traveling roller 1, a brake roller 2 and a connecting seat 3, wherein the two ends of the traveling roller 1 are respectively rotatably connected to a connecting seat 3, and the two ends of the brake roller 2 are respectively fixedly connected to the connecting seat 3 at the first end of the traveling roller 1, that is, the two ends of the two traveling rollers 1 are both rotatably connected to the connecting seat 3, and the connecting seats 3 of the two traveling rollers 1 near one end of the brake roller 2 are both fixedly connected to the brake roller 2, forming a roller-type electromagnetic stirring structure with a braking function of a traveling roller-brake roller-traveling roller.

[0044] Key references to the structure of the traveling roller 1 Figure 3 , including a traveling wave roller core 11, a traveling wave coil 12 and a roller sleeve 13. The traveling wave coil 12 is wound on the traveling wave roller core 11, and the roller sleeve 13 is sleeved on the outside of the traveling wave coil 12. The two ends of the roller sleeve 13 are mechanically sealed to facilitate sealing, protection and cooling of the traveling wave coil 12. Preferably, the outer surface of the roller sleeve 13 is processed with grooves to prevent slag accumulation during operation. The traveling wave roller core 11 is rotatably connected to the connecting seat 3, wherein the traveling wave coil 12 generates a traveling wave magnetic field when energized. The traveling wave magnetic field will generate a lateral thrust parallel to the wide surface of the billet 5, pushing the liquid core of the billet 5 to circulate. The two traveling wave rollers 1 are respectively arranged at the two ends of the brake roller 2, which will form two circulating stirrings in the liquid core of the billet 5.

[0045] Specifically, the connecting seat 3 includes a bearing seat 31, which defines a cavity. A bearing 32 is nested within the cavity of the bearing seat 31. The open end of the cavity of the bearing seat 31 is sealed and connected to a bearing cap 33, which seals the interior of the bearing seat 31, protects and lubricates the bearing 32, and constrains the position of the bearing 32. The diameters of the two ends of the traveling roller core 11 are smaller than the diameter of the middle winding portion. The two ends of the traveling roller core 11 are fixedly connected to the bearing caps 33. Mechanical seals are provided at the smaller diameters of the two ends of the traveling roller core 11, and the roller sleeve 13 is connected to the bearing 32 via the mechanical seals. In other words, the mechanical seals are provided at the two ends of the traveling roller core 11, and the two ends of each mechanical seal are fixedly connected to the corresponding roller sleeve 13 and the bearing 32. The mechanical seals can seal the bearing 32 and both ends of the roller sleeve 13, while also enabling the roller sleeve 13 to rotate on the connecting seat 3 via the bearing 32. The connecting seat 3 is used to support the traveling roller 1 and reduce the friction between the roller sleeve 13 of the traveling roller 1 and the casting billet 5 to prevent the traveling roller from being damaged.

[0046] The structure of brake roller 2 is mainly referenced Figures 4 to 9, which includes an outer cylinder 20, an arc-shaped enclosure 25, a brake roller core 27, and an end cap 28. The two ends of the outer cylinder 20 are respectively fixedly connected to the connecting seat 3 located at the first end of the traveling roller 1. The arc-shaped enclosure 25 is semicircular, and the two arc-shaped enclosures 25 are sealed together to form a hollow cylinder. The hollow cylinder is installed inside the outer cylinder 20 and is parallel to the axial direction of the outer cylinder 20. A gap is left between the outer surface of the hollow cylinder and the inner surface of the outer cylinder 20 to facilitate the passage of cooling medium and wires through the gap. The two ends of the arc-shaped enclosure 25 are respectively sealed together with the inner side of the end cap 28. Specifically, in this embodiment, a circular groove corresponding to the hollow cylinder formed by the arc-shaped enclosure 25 is opened on the inner side of the end cap 28. An O-ring is installed in the circular groove. The two ends of the arc-shaped enclosure 25 are respectively clamped in the circular groove to be fixed and form a seal. The place where the two arc-shaped enclosures 25 abut is sealed by providing a sealing ring or applying a sealing paint, etc., which is not specifically limited here. The curved enclosure 25 and end cap 28 are sealed together to form a sealed hollow cylinder. The brake roller core 27 and brake coil are secured within this hollow cylinder, effectively isolating and protecting the brake coil and brake roller core 27. The brake roller core 27 is perpendicular to the axis of the outer cylinder 20 and has a waist-shaped cross-section. The brake coil is wound around the brake roller core 27. The waist-shaped shape of the brake roller core 27, with semicircular ends and a rectangular center, has one side of the middle rectangle parallel to the ingot 5. This allows the brake roller core 27 to be closer to the ingot 5, and the area of ​​the brake roller core 27 closest to the ingot 5 is larger. The magnetic flux generated by the brake coil primarily emanates from one end of the brake roller core 27, passing through the ingot 5 to reach the brake roller 2 on the other side. The closer proximity of the brake roller cores 27 on opposite sides and the larger contact area minimizes magnetic flux loss in the air, resulting in a more effective magnetic braking effect. In this embodiment, the upper and lower edges of the brake roller core 27 are chamfered to accommodate more coil windings and facilitate installation. The brake roller core 27 is oriented perpendicular to the spindle 11. When the brake coil is energized, it generates a braking magnetic field perpendicular to the traveling magnetic field. This braking magnetic field generates a longitudinal thrust parallel to the wide surface of the ingot 5, braking the central portion of the wide surface of the ingot 5 where circulation velocity is higher, thus preventing excessively high circulation velocity in the central portion.

[0047] Furthermore, the brake roller 2 also includes an insulating baffle 26 and a threaded connecting rod 23. The inner surface of the arc-shaped enclosure 25 is inscribed inwardly with the insulating baffle 26. The insulating baffle 26 can be approximately semicircular. The two insulating baffles 26 form an approximately cylindrical shape and are inscribed inwardly with the inner surface of the arc-shaped enclosure 25. At the same time, the insulating baffle 26 is sleeved on the outer surface of the brake coil to insulate and protect the brake coil to prevent leakage accidents. In other embodiments, the insulating baffle 26 can also be set to other structures such as an integral type.

[0048] The overall structure of the brake roller 2 is installed and fixed with key references Figures 4-5One end of the brake roller core 27 has a threaded hole corresponding to the threaded connecting rod 23. The curved enclosure 25 and insulating baffle 26 located at one end of the threaded hole in the core 27 each have through-holes. The first end of the threaded connecting rod 23 passes through the through-holes in the curved enclosure 25 and insulating baffle 26 and is threadedly connected to the threaded hole in the core for securement. Furthermore, a countersunk hole is defined around the through-hole in the curved enclosure 25. The second end of the threaded connecting rod 23 is threadedly connected to a nut 22. Once secured, the nut 22 is seated in the countersunk hole in the curved enclosure 25. After the nut 22 is secured, the countersunk hole is filled with a waterproof coating for sealing. At the same time, a card groove 201 is provided on the inner surface of the outer cylinder 20, and a special-shaped key 21 is clamped in the card groove 201. A V-shaped groove 211 is provided at one end of the special-shaped key 21. The groove direction of the V-shaped groove 211 is perpendicular to the threaded connecting rod 23. After the threaded connecting rod 23 is fixed to the nut 22, the upper end of the protruding threaded connecting rod 23 will protrude from the surface of the nut 22. The upper end of the protruding threaded connecting rod 23 is just clamped in the V-shaped groove 211, which is used to constrain the threaded connecting rod 23 from axial movement inside the outer cylinder 20, thereby realizing the overall fixation of the brake roller core 27, the insulating baffle 26 and the outer cylinder 20. The structure is simple and maximizes the utilization of the internal space of the outer cylinder 20.

[0049] In this embodiment, the length of the brake roller 2 is 1 / 3 to 2 / 3 of the length of the traveling roller 1. In this embodiment, the length of the brake roller 2 is preferably 2 / 3 of the length of the traveling roller 1. The brake roller 2 is mainly used to brake the liquid core circulation of the casting slab 5 generated by the traveling roller 1. It is not necessary to form a very wide braking magnetic field. Under the premise of ensuring the braking effect, the length of the brake roller 2 can be appropriately reduced, which simplifies the structure, saves layout space, and reduces power consumption.

[0050] In the brake roller 2, a threading hole is provided on the threaded connecting rod 23. The two end terminals of the brake coil of the brake roller 2 are led out into the gap between the outer cylinder 20 and the arc-shaped enclosure 25 through the threading hole, and then pass through the gap to the outside of the outer cylinder 20 and connect to the external power supply for power supply. The threading hole on the threaded connecting rod 23 is filled with waterproof material for sealing to prevent water leakage.

[0051] In this embodiment, a terminal box 4 is fixedly connected to the connection base 3 on the end of the undulating roller 1 facing away from the brake roller 2. In other words, both undulating rollers 1 are provided with a terminal box 4 on the end facing away from the brake roller 2. The terminal box 4 houses cooling water and power connections. Grooves are defined at the smaller diameters of the undulating roller core 11 at both ends. Mechanical seals fit over and cover the grooves at both ends of the undulating roller core 11. Cooling water from the cooling water connections flows through the grooves into the roller sleeve 13, cooling the undulating coil 12 within the sleeve 13. The cooling water then flows out from the other end of the undulating roller 1, through the gap formed in the brake roller 1, and finally out of the second undulating roller 2. The undulating coil 12 is connected to an external power source via the power connection in the terminal box 4.

[0052] Preferably, the traveling wave roller core 11 is formed of silicon steel laminations, a groove structure is opened on the surface of the traveling wave roller core 11, and the traveling wave coil 12 is routed through the groove structure on the traveling wave roller core 11.

[0053] Example 2

[0054] This embodiment provides a method for using a roller-type electromagnetic stirring device with a braking function. Figures 10-13 Roller electromagnetic stirring devices A with braking functions are installed in pairs in the secondary cooling zone of the slab 5. Each pair of roller electromagnetic stirring devices A with braking functions is symmetrically installed near the upper and lower surfaces of the slab 5. At least two pairs of roller electromagnetic stirring devices A with braking functions are installed in the secondary cooling zone of the slab 5, wherein at least one pair of roller electromagnetic stirring devices A with braking functions is installed at the end near the crystallizer 7, and at least one pair of roller electromagnetic stirring devices A with braking functions is installed at the end away from the crystallizer 7. In this embodiment, preferably, three pairs (a total of six) of roller electromagnetic stirring devices A with braking functions are symmetrically installed. The six roller electromagnetic stirring devices A with braking functions replace the clamping rollers B on the thin slab continuous casting machine, wherein two pairs of roller electromagnetic stirring devices A with braking functions are located adjacent to and below the crystallizer 7, and the other pair of roller electromagnetic stirring devices A with braking functions is located at the end away from the crystallizer 7. Specifically, in this embodiment, the roller electromagnetic stirring devices A with braking functions located at the end away from the crystallizer 7 are 1.5 meters away from the crystallizer.

[0055] Since the surface of the continuous casting billet is sprayed with cooling water and the surface of the billet 5 is in contact with the air, heat can be easily dissipated. However, if the temperature of the unsolidified molten steel in the middle of the billet 5 is not controlled by electromagnetic flow to force the hot molten steel to flow near the surface, the heat transfer rate is very slow. As a result, the molten steel that originally flowed through the electromagnetic stirring roller near the crystallizer 7 stops exchanging heat with the outer surface after exceeding the flow control range of the electromagnetic roller, causing the core temperature to be much higher than the surface, thereby forming a large temperature gradient difference and generating secondary columnar crystals. Therefore, it is necessary to add an electromagnetic stirring rod far away from the crystallizer (within 2 meters).

[0056] The specific working principle of the roller type electromagnetic stirring device with braking function provided by the present invention is as follows: Figures 11-13As shown, a brake roller 2 is provided between the two wavy rollers 1, and the wavy rollers 1 at both ends generate transverse electromagnetic forces F1 and F2 parallel to the wide surface of the ingot, respectively. The transverse electromagnetic forces F1 and F2 push the unsolidified liquid core of the secondary cooling zone of the ingot 5 to stir and form two small circulations. The two small circulations will be superimposed in the middle of the wide surface of the ingot 5, resulting in an excessively fast circulation speed in the middle. At the same time, there is a water inlet 6 above the crystallizer 7. The molten steel flowing out of the water inlet 6 flows downward, which will further accelerate the circulation speed in the middle near the crystallizer 7. At this time, the brake roller 2 located in the middle will generate a longitudinal electromagnetic force F3 parallel to the wide surface of the ingot. The direction of the force of F3 is opposite to the flow direction of the molten steel, which can produce a deceleration and braking effect on the excessive circulation speed of the liquid core in the middle of the wide surface of the ingot, and control the circulation speed in the middle within an appropriate range. On the one hand, it avoids the flow drum from impacting too deeply, causing disturbance of the liquid surface at the crystallizer 7, and preventing serious quality problems such as slag rolling. This also provides a guarantee for the electromagnetic stirring roller to be installed close to the crystallizer. The closer the electromagnetic stirring roller is to the crystallizer 7, the sooner the high-temperature molten steel coming out of the crystallizer can be dissipated, preventing the formation of columnar crystals.

[0057] At the same time, the two electromagnetic stirring rods at the near and far ends of the crystallizer 7 will overlap in the middle to form two closed circulations, among which the circulation speed near the middle will be further superimposed and accelerated. At this time, the brake roller 2 provides a braking force F3, which can disperse the concentrated middle circulation, enhance the uniform dispersion of components and heat in the molten steel, and avoid the slag inclusion impact being too deep to be removed, causing serious quality problems.

[0058] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A roller type electromagnetic stirring device with a braking function, characterized in that: It comprises a traveling roller (1), a brake roller (2) and a connecting seat (3), wherein both ends of the traveling roller (1) are rotatably connected to the connecting seat (3), and both ends of the brake roller (2) are fixedly connected to the connecting seat (3) at the first end of the traveling roller (1); The traveling wave roller (1) comprises a traveling wave roller core (11), a traveling wave coil (12) and a roller sleeve (13); the traveling wave coil (12) is wound on the traveling wave roller core (11); the roller sleeve (13) is sleeved on the outside of the traveling wave coil (12) to seal the traveling wave coil (12); the traveling wave roller core (11) is fixedly connected to the connecting seat (3); the roller sleeve (13) is rotatably connected to the connecting seat (3); and the traveling wave coil (12) generates a traveling wave magnetic field when energized; The brake roller (2) comprises an outer cylinder (20), an arc-shaped enclosure (25), a brake roller core (27) and an end cover (28), the two ends of the outer cylinder (20) are respectively fixedly connected to the connecting seats (3) of the first ends of the two traveling wave rollers (1), the arc-shaped enclosure (25) is semicircular, and the two arc-shaped enclosures (25) are sealed and connected to form a hollow cylinder, the two ends of the arc-shaped enclosure (25) are respectively sealed and connected to the end cover (28), a gap is left between the outer surface of the hollow cylinder and the inner surface of the outer cylinder (20), the brake roller core (27) is fixedly installed in the hollow cylinder and is perpendicular to the axial direction of the outer cylinder (20), the cross section of the brake roller core (27) is waist-shaped, and a brake coil is wound on the brake roller core (27), and the brake coil generates a brake magnetic field perpendicular to the traveling wave magnetic field when energized; The brake roller (2) further includes an insulating baffle (26), the inner surface of the arc-shaped enclosure (25) is inscribed in the insulating baffle (26), and the insulating baffle (26) is sleeved on the outer surface of the brake coil; The brake roller (2) further includes a threaded connecting rod (23), one end of the brake roller core (27) is provided with a threaded hole corresponding to the threaded connecting rod (23), and the arc-shaped enclosure (25) and the insulating baffle (26) located at one end of the threaded hole of the brake roller core (27) are both provided with through holes, the first end of the threaded connecting rod (23) passes through the through holes on the arc-shaped enclosure (25) and the insulating baffle (26) and is threadedly connected to the threaded hole of the brake roller core (27), and the threaded connecting rod (23) is threadedly connected to the nut (22) from the second end; A countersunk hole is provided on the outer periphery of the through hole of the arc-shaped enclosing plate (25), and a waterproof coating (24) is filled in the countersunk hole. A clamping groove (201) is provided on the inner surface of the outer cylinder (20), and a special-shaped key (21) is clamped in the clamping groove (201). A V-shaped groove (211) is provided at one end of the special-shaped key (21), and a second end of the threaded connecting rod (23) is clamped in the V-shaped groove (211). The connecting seat (3) includes a bearing seat (31), a bearing (32) is nested and installed in the bearing seat (31), the open end of the bearing seat (31) is sealed and connected to the bearing cover (33), the diameters of the two ends of the traveling wave roller iron core (11) are smaller than the middle diameter, the two ends of the traveling wave roller iron core (11) are fixedly connected to the bearing cover (33), and the small diameters of the two ends of the traveling wave roller iron core (11) are sleeved with mechanical sealing devices, and the roller sleeve (13) is connected to the bearing (32) through the mechanical sealing device; An outlet box (4) is fixedly connected to a connecting seat (3) at one end of the traveling wave roller (1) away from the brake roller (2). A cooling water pipe joint and a power supply joint are provided in the outlet box (4). The cooling water pipe joint is connected to the roller sleeve (13) to cool the traveling wave coil (12). The traveling wave coil (12) is connected to an external power supply via the power supply joint.

2. The roller type electromagnetic stirring device with braking function according to claim 1, characterized in that: The threaded connecting rod (23) is provided with a threading hole, through which the two ends of the brake coil are led out to the gap between the outer cylinder (20) and the arc-shaped enclosure plate (25), and the threading hole is filled with a waterproof material for sealing.

3. The roller type electromagnetic stirring device with braking function according to claim 1, characterized in that: A circular groove corresponding to the arc-shaped enclosure plate (25) is provided on the inner side of the end cover (28), an O-ring (29) is installed in the circular groove, and both ends of the arc-shaped enclosure plate (25) are respectively clamped in the circular groove.

4. The roller type electromagnetic stirring device with braking function according to claim 1, characterized in that: The length of the brake roller (2) is 1 / 3 to 2 / 3 of the length of the traveling roller (1).

5. A method for using the roller-type electromagnetic stirring device with a braking function according to any one of claims 1 to 4, characterized in that: The roller electromagnetic stirring devices (A) with a braking function are installed in pairs in the secondary cooling zone of the ingot (5), and any pair of the roller electromagnetic stirring devices (A) with a braking function are symmetrically installed near the upper and lower surfaces of the ingot (5). At least two pairs of the roller electromagnetic stirring devices (A) with a braking function are arranged in the secondary cooling zone, wherein at least one pair of the roller electromagnetic stirring devices (A) with a braking function is arranged at one end close to the crystallizer (7), and at the same time, at least one pair of the roller electromagnetic stirring devices (A) with a braking function is arranged at one end away from the crystallizer (7).

Images