A method for preventing nozzle clogging and erosion of a slag line by independently applying an electric field to each zone
Patent Information
- Application Number
- CN202611488059.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-23
- Publication Date
- 2026-11-03
AI Technical Summary
Existing technologies cannot simultaneously and effectively prevent the formation of nodules on the inner wall of the submerged nozzle and the erosion of the slag line, resulting in a high risk of nozzle failure during continuous casting and affecting production safety and quality.
By adopting a method of applying electric fields independently in different zones, conductive rings are arranged on the upper and lower parts of the submersible nozzle body to form an upper repulsive electric field and a lower protective electric field. The electric field parameters of each zone are controlled by an independent power source to suppress the migration of inclusions and the erosion of protective slag.
This technology simultaneously prevents nodule formation and slag line erosion on the inner wall of the submerged nozzle, extends the service life of the nozzle, improves the quality of the cast billet and the stability of continuous casting production, and reduces the risk of shutdown.
Smart Images
Figure CN123024875A_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of continuous casting production technology in iron and steel metallurgy, and particularly relates to a method for preventing nodule formation and slag line erosion in an immersion nozzle by applying an electric field to different zones independently. Background Technology
[0002] In recent years, the service life and metallurgical performance of functional refractory materials for metallurgy (such as tundishes and steel ladles) have been continuously improving, placing higher demands on the service life of continuous casting nozzles. Submerged entry nozzles are key components connecting the mold and tundish in the continuous casting process, playing a crucial role in preventing secondary oxidation of molten steel. During casting, submerged entry nozzles mainly face two core problems: nodule formation on the inner wall and slag line erosion. Nodule formation on the inner wall can narrow or even completely block the steel flow channel, forcing casting to be interrupted and severely affecting the continuous casting operation rate and billet quality. Meanwhile, the slag line area of the nozzle, due to long-term chemical erosion and mechanical scouring, is prone to thinning or even perforation and steel leakage, seriously threatening production safety.
[0003] Nodule formation on the inner wall of the sprue is caused by the migration, deposition, and sintering of positively charged inclusions such as alumina in the molten steel. Traditional physical anti-clogging methods, such as argon purging, can alleviate blockage, but they easily lead to secondary defects such as slag entrapment and bubble entrainment. Studies have shown that during casting, the surface of the inner wall of the submerged nozzle carries a negative charge, while the alumina inclusions in the molten steel carry a positive charge. This electrostatic attraction causes the inclusions to migrate towards the inner wall of the nozzle, eventually forming a nodule layer. Existing technology applies a positive electric field to the inner wall of the submerged nozzle (i.e., the nozzle is the positive pole), utilizing the principle of repulsion to inhibit the migration and adhesion of inclusions to the inner wall.
[0004] Studies have shown that applying a positive electric field can reduce the thickness of the nodule layer on the inner wall of the nozzle by 20%–35%, significantly extending the continuous casting time. Furthermore, research indicates that applying a negative electric field to the refractory material of the slag line (i.e., with the nozzle as the negative electrode) can form a dense protective layer on the slag line surface, hindering the penetration and reaction of components such as CaO and SiO2 in the protective slag into the slag line area, thereby reducing the slag line erosion rate. However, in existing technologies, whether the nozzle is connected to the positive or negative electrode, it is impossible to simultaneously prevent nodule formation and slag line erosion, thus limiting the application of electric field control in submerged entry nozzles. Summary of the Invention
[0005] To address some or all of the technical problems existing in the prior art, this application provides a method for preventing nodule formation and slag line erosion by applying an electric field independently to different zones in an immersion nozzle.
[0006] This application provides a method for preventing nodule formation and slag line erosion in an immersion nozzle by applying an electric field to different zones independently, comprising the following steps: Step S1: An upper conductive ring and a lower conductive ring are respectively arranged along the axial direction on the outer wall of the immersion nozzle body made of conductive refractory material; an electrical isolation structure is set between the upper conductive ring and the lower conductive ring to block the current crossflow between the two electric fields. Step S2: Connect the upper conductive ring to the positive terminal of the first power source. Use the molten steel inside the tundish as the conductive medium. Combined with the cathode component inside the tundish, form an upper closed loop. Create a repulsive electric field on the inner wall of the submerged nozzle body to inhibit the migration and deposition of positively charged inclusions in the molten steel onto the inner wall of the submerged nozzle body. Step S3: Connect the lower conductive ring to the negative terminal of the second power supply. Use the protective slag layer inside the crystallizer as the conductive medium. Combined with the anode component set on the crystallizer side, form a lower closed circuit to suppress the penetration and erosion of the protective slag on the corresponding part of the refractory material of the submerged nozzle body. Step S4: The first power supply and the second power supply are electrically isolated from each other, and the electric field parameters of the two circuits are adjusted independently.
[0007] Preferably, the upper end of the submerged nozzle body is installed at the bottom outlet of the tundish, and the submerged nozzle body hangs downward with its lower end extending into the molten steel inside the crystallizer below the surface of the molten steel; the upper conductive sleeve is located axially below the bottom outlet of the tundish, and the lower conductive sleeve is located above the protective slag layer of the crystallizer.
[0008] Preferably, in step S1, an circumferential groove is formed at a corresponding position on the outer wall of the immersion nozzle body, and the upper conductive sleeve and the lower conductive sleeve are embedded in the circumferential groove.
[0009] Preferably, the gap between the fixed circumferential groove is filled with a high-temperature resistant insulating sealing material; the outer sides of the upper conductive ring and the lower conductive ring are covered with a fire-resistant protective layer, which covers the opening of the circumferential groove.
[0010] Preferably, the conductive sleeve is made of a high-temperature conductive material with a melting point ≥1300℃, including any one of platinum, nickel, molybdenum, or iron, and the thickness of the conductive sleeve is 5mm; wherein the upper conductive sleeve is located 30~55cm above the slag line in the immersion nozzle body area, and the lower conductive sleeve is located in the slag line area. The groove width of the circumferential groove is 1.5~2cm, and the groove depth is 1.2~1.7cm; the high-temperature insulating sealant is a high-temperature insulating sealant with a carbon content ≥12%; and the fire-resistant protective layer is fire-resistant cotton. As an alternative embodiment, a high-temperature wire with a diameter of 0.5~2mm can be uniformly wound inside the circumferential groove to replace the integral conductive sleeve.
[0011] Preferably, in step S1, the electrical isolation structure includes a pre-reserved axial physical distance between the upper and lower conductive sleeves, and a high-temperature insulating material coated on the outer wall of the immersion nozzle body in the distance area. The high-temperature insulating material can be an insulating ceramic layer, high-temperature refractory mortar, etc. Independent high-temperature wires are led out from the upper and lower conductive sleeves respectively, and ceramic protective sleeves are installed at the wire leads, which are respectively connected to independent power supply junction boxes; the two power supplies are completely electrically isolated and share a common ground.
[0012] Preferably, in step S2, the cathode component inside the tundish is a stopper rod, which is electrically connected to the negative terminal of the first power supply. An insulating sleeve is provided at the stopper rod's terminals to achieve electrical isolation between the circuit and the stopper rod control mechanism. As an alternative implementation, an independent graphite electrode can also be provided inside the tundish as the cathode component.
[0013] Preferably, in step S3, the anode component of the crystallizer is an independent graphite rod; the independent graphite rod is electrically connected to the positive terminal of the second power supply, and its lower end extends into the protective slag layer of the crystallizer during operation.
[0014] Preferably, the individual graphite rod is mounted on an independent support, and the independent support is equipped with a lifting and adjusting mechanism. The diameter of the individual graphite rod is 5~8cm and the length is 1~1.5m.
[0015] Preferably, the upper closed loop uses a DC electric field; the lower closed loop uses a DC electric field or a pulsed electric field. The output voltage is set to ≤36V, and the output current is controlled between 2A and 60A; when using a pulsed electric field, the pulse frequency is 1000Hz~50000Hz, the duty cycle is controlled between 40% and 70%, and the pulse parameters are matched with the viscosity-temperature characteristics of the protective slag.
[0016] Preferably, the method further includes a shielding protection step: annular electromagnetic shielding covers are respectively assembled around the upper and lower conductive rings, and the electromagnetic shielding covers are equipotentially connected to the corresponding conductive rings; the electromagnetic shielding cover includes a frame and a shielding layer. The frame consists of two semi-ring structures made of high-temperature resistant metal materials, such as molybdenum or tantalum; its inner diameter in its natural state is less than or equal to the outer diameter of the immersion nozzle body. The two semi-ring structures are tightly attached to the outer wall of the immersion nozzle body by radial clamping force generated by the snap-fit, forming a self-locking fixation through the combined action of friction and clamping force; the shielding layer consists of an outer molybdenum reflective layer, a middle ferrite material absorbing layer, and an inner high-temperature insulating ceramic coating. The thickness of the shielding cover itself is 1.5~3.0mm; the electromagnetic shielding cover extends 40mm axially above and below the corresponding conductive ring.
[0017] The method for preventing nodule formation and slag line erosion in immersion nozzles by applying independently zoned electric fields in this application has the following advantages and positive effects: By arranging two independent electric field circuits in the axial section of the submerged nozzle body, the upper positive electric field inhibits the deposition of inclusions on the inner wall, while the lower negative electric field resists the erosion of the nozzle outer wall by the protective slag. This solves the technical problem that existing technologies cannot simultaneously prevent nodule formation and resist protective slag erosion. It can achieve dual protection on the same nozzle component, effectively reducing the risk of casting stoppage caused by nozzle failure, extending the service life of the submerged nozzle body, improving the cleanliness of molten steel, and enhancing the quality of cast billets and the overall stability of continuous casting production. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for further understanding of the embodiments of this application and constitute a part of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the immersion nozzle with independently applied electric field in each zone, as described in this application. Figure 2 This is a schematic diagram of the arrangement of the conductive sleeve below the slag line in this application; Explanation of reference numerals in the attached figures: 1-First power source, 2-stopper rod, 3-intermediate ladle, 4-molten steel, 5-immersion nozzle body, 6-insulating ceramic layer, 7-crystallizer, 8-second power source, 9-independent graphite rod, 10-large ladle long nozzle, 11-upper conductive ring, 12-lower conductive ring, 13-crystallizer protective slag layer, 14-independent support. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0020] This embodiment uses an immersion nozzle made of MgO-C or ZrO2-C conductive refractory material as the implementation object. The entire continuous casting system is also equipped with a ladle long nozzle 10, which is a conventional upstream casting component for continuous casting.
[0021] The specific implementation process is as follows: Step S1: Preparation of partitioned conductive rings and setting up electrical isolation A submersible nozzle body 5, made of conductive refractory material, is machined with circumferential grooves at two different heights along the axial direction on its outer wall. The upper circumferential groove is located in the submersible nozzle body 5, corresponding to a position 30-55 cm above the slag line; the lower circumferential groove is located in the submersible nozzle body 5 corresponding to the slag line, with the lower edge of the groove at least 50 mm above the upper surface of the protective slag layer 13 of the crystallizer. The width of the circumferential grooves is controlled to be 1.5-2 cm, and the depth is controlled to be 1.2-1.7 cm. After the grooves are machined, dust and impurities inside the grooves are cleaned to ensure that the inner surface of the grooves is smooth and free of cracks.
[0022] An upper conductive ring 11 and a lower conductive ring 12 are prepared. The conductive rings are made of a high-temperature resistant conductive material with a melting point ≥1300℃, and can be any one of platinum, nickel, molybdenum, or iron. The thickness of a single conductive ring is 5mm. The two conductive rings are respectively embedded into the corresponding circumferential grooves. The groove gaps are filled with a high-temperature resistant insulating sealant with a carbon content ≥12% to fix the conductive rings and seal the grooves. Then, fire-resistant cotton is wrapped around the outside of the conductive rings as a fire-resistant protective layer. The fire-resistant protective layer completely covers the groove opening and isolates the conductive rings from the corrosion of high-temperature fumes and molten slag splashes. As an alternative implementation scheme in the field, a high-temperature wire with a diameter of 0.5~2mm can also be uniformly wound inside the circumferential groove to replace the integral conductive ring.
[0023] An electrical isolation structure is installed between the upper conductive ring 11 and the lower conductive ring 12: First, an axial physical distance of more than 10cm is reserved between the two conductive rings. Second, a high-temperature insulating ceramic layer 6 is coated on the outer wall of the immersion nozzle body 5 in this distance area. The current cross-flow between the two electric fields is blocked by the combined effect of the physical distance and the insulating coating. Independent high-temperature wires are led out from the upper conductive ring 11 and the lower conductive ring 12 respectively. Ceramic protective sleeves are installed at the wire exit points. The wires can be fixedly extended along the outer wall of the immersion nozzle body 5 to the top of the intermediate package 3 and connected to their respective independent power supply junction boxes. The two power supply systems are completely electrically isolated and only share a grounding terminal.
[0024] Before powering on, an insulation resistance test is performed to verify that the two zones of electric fields can be applied independently without interfering with each other, and there is no risk of short circuit.
[0025] Step S2: Construction of the upper closed loop The positive wire of the first power source 1 is connected to the upper conductive sleeve 11. The cathode component inside the tundish 3 uses the original stopper rod 2 from the continuous casting equipment. The negative wire of the first power source 1 is connected to the stopper rod 2. The terminals of the stopper rod 2 are fitted with insulating sleeves to ensure electrical isolation between the electric field circuit and the control mechanism of the stopper rod 2. This forms an upper closed loop, and the current path is: positive terminal of the first power source 1 → upper conductive sleeve 11 → upper part of the immersion nozzle body 5 → molten steel 4 inside the tundish 3 → stopper rod 2 → negative terminal of the first power source 1.
[0026] After energization, the upper circuit forms a repulsive positive electric field on the inner wall of the submersible nozzle body 5. Utilizing the principle of repulsion between like charges, this inhibits the migration and deposition of positively charged alumina inclusions in the molten steel onto the inner wall of the submersible nozzle body 5, thus delaying nodule formation. If the site conditions are not suitable for using the stopper rod 2 as the cathode, an independent graphite electrode can be separately installed inside the tundish 3 as the cathode component, connected to the negative terminal of the first power supply 1 to form a circuit.
[0027] Step S3: Construction of the lower closed loop The negative wire of the second power supply 8 is connected to the lower conductive sleeve 12. The anode component on the crystallizer 7 side is an independent graphite rod 9. The independent graphite rod 9 has a diameter of 5~8cm and a length of 0.8~1.2m. It is fixed to an independent bracket 14 by a clamp. The independent bracket 14 is equipped with an automatic lifting and adjustment mechanism and is installed above the crystallizer 7. The top of the independent graphite rod 9 is slotted to connect a high-temperature wire. The joint is coated with high-temperature refractory mortar for anti-oxidation protection. The other end of the wire is connected to the positive terminal of the second power supply 8.
[0028] During production operation, the height of the independent graphite rod 9 is adjusted by the lifting mechanism of the independent support 14, so that its lower end is stably inserted into the molten layer of the crystallizer protective slag layer 13. This forms a lower closed loop, and the current path is: positive terminal of the second power supply 8 → independent graphite rod 9 → crystallizer protective slag layer 13 → outer wall of the corresponding area of the submerged nozzle body 5 → lower conductive ring 12 → negative terminal of the second power supply 8.
[0029] After energization, the lower circuit forms a protective negative electric field in the area corresponding to the slag line of the submerged nozzle body 5, causing the protective slag to form a uniform and dense viscous protective layer on the outer wall of the nozzle, hindering the penetration of the protective slag components into the refractory material and reducing the slag line erosion rate. The lifting mechanism of the independent support 14 can adjust the insertion depth in real time according to the erosion rate of the independent graphite rod 9, ensuring that the independent graphite rod 9 is always in an effective working position; the independent graphite rod 9 can be quickly replaced during continuous casting intervals after wear.
[0030] Step S4: Independent adjustment of electric field parameters The first power supply 1 and the second power supply 8 are electrically isolated from each other and can independently adjust parameters such as voltage, current, and electric field type. The electric field strength and distribution are dynamically optimized according to process conditions such as steel grade, casting speed, and protective slag type. The output voltage of both circuits is controlled to ≤36V, and the output current is controlled between 2A and 60A.
[0031] The upper closed loop uses a DC electric field to continuously and stably output repulsive force, suppressing the adhesion of inclusions. The parameters of the upper electric field are adjusted based on the thickness of the nodule buildup on the inner wall of the submerged nozzle body 5 after casting. The lower closed loop can select either a DC electric field or a pulsed electric field according to the working conditions. When using a pulsed electric field, the pulse frequency is adjusted between 1000Hz and 50000Hz, and the duty cycle is controlled between 40% and 70% to match the pulse parameters with the viscosity-temperature characteristics of the protective slag, promoting the melting and lubrication of the protective slag and optimizing the film formation effect. The parameters of the lower electric field are adjusted based on the degree of slag line erosion suppression under the same working conditions.
[0032] Step S5, Shielding and Protection Steps As a preferred embodiment, annular electromagnetic shielding covers are respectively installed around the upper conductive ring 11 and the lower conductive ring 12 to further enhance the independence of the electric field, reduce interference from external electromagnetic stirring devices, and ensure the stability and accuracy of electric field control.
[0033] The electromagnetic shielding cover consists of two parts: an elastic frame and a composite shielding layer. The elastic frame is composed of two semi-ring structures made of high-temperature resistant metal materials such as molybdenum or tantalum. In its natural state, the inner diameter of the frame is 0.4 mm smaller than the outer diameter of the immersion nozzle body 5, forming an interference fit. The two semi-rings are closed by snap-fit. During installation, the radial clamping force generated by the elastic deformation tightly adheres to the outer wall of the immersion nozzle body 5. Self-locking is achieved through the combined action of friction and clamping force, eliminating the need for additional slots on the outer wall of the nozzle and avoiding weakening the structural strength of the nozzle.
[0034] The composite shielding layer is fixedly installed inside the frame and consists of three layers: an outer 0.3mm thick molybdenum reflective layer to reflect stray electric field energy; a middle 0.5mm thick ferrite absorption layer to absorb stray magnetic fields; and an inner 0.2mm thick high-temperature insulating ceramic coating to achieve electrical isolation between the shielding cover and the outer wall of the immersion nozzle body 5. The shielding cover itself has a thickness of 1.5~3.0mm; the electromagnetic shielding cover extends 40mm above and below the corresponding conductive ring in the axial direction. After installation, the upper shielding cover is connected to the upper conductive ring 11 at the same potential, and the lower shielding cover is connected to the lower conductive ring 12 at the same potential. That is, the upper shielding cover is connected to the positive terminal of the first power supply 1 along with the upper conductive ring 11, and the lower shielding cover is connected to the negative terminal of the second power supply 8 along with the lower conductive ring 12. This achieves electric field reflection and stray magnetic field absorption, blocks the mutual interference between the two sets of partitioned electric fields, and weakens the magnetic field interference brought by the external electromagnetic stirring device.
[0035] Most existing submerged nozzle electric field control technologies treat the entire nozzle as a single electrode, which can only apply a unipolar electric field. This cannot simultaneously meet the positive potential required for anti-nodulation on the inner wall of the submerged nozzle body 5 and the negative potential required for erosion resistance at the slag line. Furthermore, there is a lack of a complete set of solutions that can achieve independent electric fields in the same submerged nozzle body 5, with molten steel 4 and the crystallizer protective slag layer 13 as the conductive media of different circuits. This application fills the technical gap in the coordinated protection of zoned potentials in the continuous casting submerged nozzle body 5.
[0036] This application employs two independent electric field circuits arranged axially in the submerged nozzle body 5. The upper positive electric field inhibits the deposition of inclusions on the inner wall, while the lower negative electric field resists the erosion of the nozzle outer wall by the protective slag. This solves the technical problem that existing technologies cannot simultaneously address both the prevention of nodule formation and the resistance to slag erosion. It can achieve dual protection effects on the same nozzle component, effectively reducing the risk of casting stoppage caused by nozzle failure, extending the service life of the submerged nozzle body 5, improving the cleanliness of molten steel, and enhancing the quality of cast billets and the overall stability of continuous casting production.
[0037] This application relies on physical spacing and insulating coating to achieve electrical isolation. Combined with a snap-locking three-layer composite equipotential shielding structure, it can ensure that the upper and lower electric fields do not interfere with each other, while resisting magnetic field interference from external electromagnetic stirring devices. The entire device can be implemented by modifying existing continuous casting equipment. The electric field parameters can be flexibly adjusted according to steel grade, casting speed, and protective slag conditions, and the process adaptability is wide.
[0038] It should be noted that, unless otherwise expressly specified and limited, the term "connection" or its synonyms should be interpreted broadly in this document. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, expressions such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. At the same time, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In addition, the terms "front," "rear," "left," "right," "upper," and "lower" in this document refer to the placement states shown in the accompanying drawings.
[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.
Claims
1. A method for preventing nodule formation and slag line erosion in an immersion nozzle by independently applying electric fields to different zones, characterized in that, Includes the following steps: Step S1: An upper conductive ring (11) and a lower conductive ring (12) are respectively arranged along the axial direction on the outer wall of the immersion nozzle body (5) made of conductive refractory material; an electrical isolation structure is set between the upper conductive ring (11) and the lower conductive ring (12) to block the current crossflow between the two electric fields. Step S2: Connect the upper conductive ring (11) to the positive terminal of the first power supply (1), use the molten steel (4) inside the tundish (3) as the conductive medium, and form an upper closed loop with the cathode component inside the tundish (3) to form a repulsive electric field on the inner wall of the submerged nozzle body (5) to inhibit the migration and deposition of positively charged inclusions in the molten steel to the inner wall of the submerged nozzle body (5). Step S3: Connect the lower conductive ring (12) to the negative terminal of the second power supply (8), use the crystallizer protective slag layer (13) inside the crystallizer (7) as the conductive medium, and form a lower closed loop with the anode component set on the side of the crystallizer (7) to suppress the penetration and erosion of the protective slag on the refractory material of the corresponding part of the submerged nozzle body (5). Step S4: The first power supply (1) and the second power supply (8) are electrically isolated from each other, and the electric field parameters of the two circuits are adjusted independently.
2. The method for preventing nodulation and slag line erosion in an immersion nozzle by independently applying electric fields to different zones according to claim 1, characterized in that, The upper end of the submerged nozzle body (5) is installed at the bottom outlet of the tundish (3). The submerged nozzle body (5) is lowered and its lower end extends into the molten steel inside the crystallizer (7) below the surface of the molten steel. The upper conductive ring (11) is located axially below the bottom outlet of the tundish (3), and the lower conductive ring (12) is located above the protective slag layer (13) of the crystallizer.
3. The method for preventing nodulation and slag line erosion in an immersion nozzle by independently applying electric fields to different zones according to claim 1, characterized in that, In step S1, an circumferential groove is opened at the corresponding position on the outer wall of the immersion nozzle body (5), and the upper conductive ring (11) and the lower conductive ring (12) are embedded in the circumferential groove.
4. The method for preventing nodulation and slag line erosion in an immersion nozzle by independently applying electric fields to different zones, as described in claim 3, is characterized in that... The gap between the fixed circumferential groove is filled with a high-temperature resistant insulating sealing material; the outer sides of the upper conductive ring (11) and the lower conductive ring (12) are covered with a fire-resistant protective layer, which covers the opening of the circumferential groove.
5. The method for preventing nodulation and slag line erosion in an immersion nozzle by independently applying electric fields to different zones according to claim 1, characterized in that, In step S1, the electrical isolation structure includes the axial physical gap reserved between the upper conductive ring (11) and the lower conductive ring (12), and the insulating ceramic layer (6) coated on the outer wall of the immersion nozzle body (5) in the gap area.
6. The method for preventing nodulation and slag line erosion in an immersion nozzle by independently applying electric fields to different zones according to claim 1, characterized in that, In step S2, the cathode component inside the intermediate package (3) is a stopper rod (2), which is electrically connected to the negative terminal of the first power supply (1).
7. The method for preventing nodulation and slag line erosion in an immersion nozzle by independently applying electric fields to different zones according to claim 1, characterized in that, In step S3, the anode component of the crystallizer (7) is an independent graphite rod (9); the independent graphite rod (9) is electrically connected to the positive terminal of the second power supply (8), and its lower end extends into the interior of the protective slag layer (13) of the crystallizer in the working state.
8. The method for preventing nodulation and slag line erosion of an immersion nozzle by independently applying electric fields to different zones according to claim 7, characterized in that, The independent graphite rod (9) is mounted on an independent bracket (14), which is equipped with a lifting and adjusting mechanism.
9. The method for preventing nodulation and slag line erosion in an immersion nozzle by independently applying electric fields to different zones according to claim 1, characterized in that, The upper closed loop uses a DC electric field; the lower closed loop uses a DC electric field or a pulsed electric field.
10. The method for preventing nodulation and slag line erosion of an immersion nozzle by independently applying an electric field to different zones according to any one of claims 1 to 9, characterized in that, It also includes a shielding protection step: annular electromagnetic shielding covers are respectively assembled around the upper conductive ring (11) and the lower conductive ring (12), and the electromagnetic shielding covers are respectively connected to the corresponding conductive rings at the same potential; the electromagnetic shielding cover includes a skeleton and a shielding layer, the skeleton is a two-half-ring structure, and the two-half-ring structure is tightly attached to the outer wall of the immersion nozzle body (5) by the radial clamping force generated by the buckle; the shielding layer is composed of an outer layer of molybdenum metal reflective layer, a middle layer of ferrite material absorption layer and an inner layer of high temperature insulating ceramic coating.