A partitioned control device and method for a twenty-roller rolling mill

Abstract

The application discloses a kind of twenty-roller mill partition control electric device and method, belong to extremely thin strip processing technical field, including rack, first intermediate roll, second intermediate roll and clamping plate, first intermediate roll and second intermediate roll contact, rack is provided with work roll, work roll and first intermediate roll contact, strip is arranged between clamping plate, work roll and strip, first intermediate roll front end is provided with positive power connector, first intermediate roll rear end is provided with negative power connector, negative power connector is connected with rolling mill connector, and flexible sleeve ring is arranged in junction. The application adopts the above-mentioned twenty-roller mill partition control electric device and method, solves the technical problems that existing twenty-roller mill cannot be electrified rolling, current transmission is discontinuous, insulation is unreliable, and cannot be partitioned control electricity, realizes accurate rolling under the condition of multi-field coupling, improves the product quality of difficult deformation metal extremely thin strip, and expands the application range of twenty-roller mill.

Description

Technical Field

[0001] This invention relates to the field of ultra-thin strip processing technology, and in particular to a zoned electrical control device and method for a 20-roll mill. Background Technology

[0002] The 20-roll mill is a highly efficient multi-roll cold rolling mill characterized by its small work roll diameter, large reduction per pass, and excellent shape control capabilities. It is widely used for rolling ultra-thin strip products. Furthermore, the 20-roll mill possesses powerful shape control capabilities, enabling precise thickness and shape adjustments through a hydraulic servo system, ensuring the flatness and thickness consistency of the finished product. With its high rigidity, excellent shape control, and adaptability, the 20-roll mill has become an indispensable piece of equipment in modern steel production, playing a particularly important role in the production of high-precision ultra-thin strip.

[0003] Electroplastic rolling is an advanced metal forming technology that combines electroplasticity with traditional rolling processes. Its core principle is to pass a high-density current through the metal material during or just before rolling deformation. The interaction between the current and the material produces a series of unique physical effects, significantly altering the material's deformation behavior and microstructure evolution. The advantages of this technology stem from the fundamental change in the deformation process caused by electroplasticity, greatly enhancing the material's formability and processing limits, and effectively improving product microstructure and properties. Specifically, directly passing an electric current through the strip during rolling produces significant electroplasticity and resistance heating effects, effectively reducing the material's deformation resistance and improving plastic flowability, making it particularly suitable for high-strength, high-hardness, or low-plasticity, difficult-to-deform materials.

[0004] However, existing 20-roll mills are mainly used for traditional cold rolling of single metal or alloy strips and do not yet have the capability to roll strips under energized conditions. This lack of capability limits the application expansion of 20-roll mills in the field of material processing. Currently, some multi-roll mills or special rolling equipment have attempted to introduce current-assisted rolling processes, but 20-roll mills have not yet integrated related functions in terms of structural design, insulation treatment, current introduction and control, etc. Furthermore, the coupling of the first intermediate roll of the 20-roll mill is insufficient during transmission, making it impossible to achieve the rolling process under electro-mechanical-thermal multi-field coupling. At the same time, when rolling Invar alloys, the Invar alloy itself has significant work hardening, high deformation resistance, and poor thermal conductivity, so it is very easy to have uneven transverse stress distribution during the rolling process, resulting in strip shape defects such as transverse curling and wavy edges. Summary of the Invention

[0005] The purpose of this invention is to provide a zoned power control device and method for a 20-roll mill, which solves the technical problems of existing 20-roll mills being unable to roll under power, having discontinuous current transmission, unreliable insulation, and being unable to control power in zones. This invention enables precise rolling under multi-field coupling, improves the product quality of difficult-to-deform ultra-thin metal strips, and expands the application range of 20-roll mills.

[0006] To achieve the above objectives, the present invention provides a zoned power control device for a 20-roll mill, comprising a frame, a first intermediate roll, a second intermediate roll, and clamping plates. The first intermediate roll, the second intermediate roll, and the clamping plates are all connected to the frame. The outer surface of the first intermediate roll is in contact with the outer surface of the second intermediate roll. A work roll is provided on the frame, and the outer surface of the work roll is in contact with the outer surface of the first intermediate roll. A strip is provided between the clamping plates, and the outer surface of the work roll is in contact with the strip. A positive power connector is provided at the front end of the first intermediate roll, and a negative power connector is provided at the rear end of the first intermediate roll. The negative power connector is connected to the mill joint, and a flexible collar is provided at the connection point.

[0007] Preferably, the first intermediate roll has a fluid chamber inside, a first interface is provided on the side wall of the fluid chamber, a fluid inlet channel is provided inside the first intermediate roll, the first interface is connected to one end of the fluid inlet channel, a fluid inlet is provided on the side wall of the mill joint, the other end of the fluid inlet channel is connected to the fluid inlet, a second interface is provided on the side wall of the fluid chamber, a fluid discharge channel is provided inside the first intermediate roll, the second interface is connected to one end of the fluid discharge channel, a fluid outlet is provided on the side wall of the mill joint, and the other end of the fluid discharge channel is connected to the fluid outlet.

[0008] Preferably, a leakage detection sensor is provided between adjacent fluid chambers. The leakage detection sensor is used to ensure that the three fluid chambers do not communicate with each other and to maintain the independent and controllable resistance of each section.

[0009] Preferably, a connecting pipe is connected to the fluid inlet, and a fluid interface and a gas interface are respectively provided at the other end of the connecting pipe. The fluid interface is used to introduce a conductive medium, and the gas interface is used to introduce a protective gas.

[0010] Preferably, the flexible collar includes a flexible conductive layer disposed on the outer surface of the first intermediate roller, and a conductive busbar is disposed outside the flexible conductive layer. The conductive busbar is used to avoid current concentration and ensure the continuity of current transmission. An insulating layer is disposed outside the conductive busbar, and the insulating layer is used to maintain insulation and prevent power leakage.

[0011] Preferably, an insulating tube is provided on the outer side of the second intermediate roller, and an insulating cavity is formed between the insulating tube and the second intermediate roller, and protective gas is introduced into the insulating cavity.

[0012] Preferably, an insulating shell is provided on the outside of the clamping plate, an air passage is provided inside the insulating shell, and air holes are provided on the outer surface of the insulating shell. The air passage is connected to the air holes, and protective gas is introduced into the air passage and ejected through the air holes to form an upper and lower convection air film.

[0013] A method for zoned power control of a 20-roll mill includes the following steps: S1: Install the fluid partition control first intermediate roll and the ordinary first intermediate roll diagonally at the first intermediate roll installation position of the twenty-roll mill, assemble the flexible collar, the second intermediate roll and the clamping plate, and connect the conductive medium conveying pipeline and the protective gas conveying pipeline. S2: Inject conductive medium into the three fluid access channels respectively, set the initial capacity of each fluid chamber according to the current-capacity calibration curve, and introduce protective gas into the insulation chamber and ventilation channel to perform system insulation and leakage detection; S3: The control system independently adjusts the capacity of the conductive medium in each fluid chamber and performs calibration to maintain the stability of the current in each zone; S4: Continuously monitor insulation status, dielectric circulation status and current stability, and promptly handle inter-section liquid penetration and abnormal current fluctuations. S5: First, introduce protective gas into each fluid chamber to purge the conductive medium, gradually reduce the current to zero, then disconnect the power supply, purge the residual medium, and clean the equipment.

[0014] Preferably, in S3, when the current is increased, the injection pump is controlled to replenish the conductive medium to the target fluid chamber; when the current is decreased, protective gas is introduced into the target fluid chamber to push out the conductive medium.

[0015] Preferably, in S4, when inter-segment fluid leakage is detected, the injection of conductive medium into the fluid chamber is immediately stopped, and protective gas is introduced to purge the conductive medium before resealing and calibration; when current fluctuation is detected, the fit of the flexible collar is checked and the capacity of the conductive medium and the pressure of the protective gas are adjusted.

[0016] Therefore, this invention employs the aforementioned zonal power control device and method for a 20-roll mill to solve the technical problems of existing 20-roll mills, such as inability to perform energized rolling, discontinuous current transmission, unreliable insulation, and inability to perform zonal power control. It achieves precise rolling under multi-field coupling, improves the product quality of extremely thin strips of difficult-to-deform metals, and expands the application range of the 20-roll mill. Through the design of three independent fluid access channels, by adjusting the capacity of the conductive medium in each fluid chamber and changing the solution resistance of the corresponding area, independent zonal control of the axial current of the work rolls is achieved. Power supply can be differentiated according to the transverse deformation characteristics of the strip, effectively solving the problem of uneven transverse stress during the rolling of difficult-to-deform materials, significantly improving strip shape quality, and reducing scrap rate. The three-layer composite structure of the flexible collar solves the problem of current interruption caused by poor joint contact. The full-circumference conductive current collection design avoids local overheating and improves the continuity and stability of current transmission. The use of an insulating tube sleeve combined with the insulation of the second intermediate roll protected by protective gas, the clamp insulation of the protective gas convection film, and the outer layer insulation of the flexible collar effectively prevents current leakage and protects the safety of the rolling mill equipment.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the 20-roll mill zoned power control device in this invention; Figure 2 This refers to the positional relationship between the insulating shell and the strip in this invention; Figure 3 This is a schematic diagram of the internal structure of the first intermediate roller in this invention; Figure 4 This is a schematic diagram of the specific structure of the connecting pipe in this invention; Figure 5 This is a schematic diagram of the specific structure of the flexible collar in this invention; Figure 6 This is a schematic diagram of the specific structure of the insulating shell in this invention.

[0019] Figure Labels 1. Frame; 2. First intermediate roll; 3. Second intermediate roll; 4. Clamping plate; 5. Work roll; 6. Strip; 7. Positive power connector; 8. Negative power connector; 9. Flexible collar; 10. Fluid chamber; 11. First interface; 12. Fluid inlet channel; 13. Fluid inlet; 14. Second interface; 15. Fluid outlet channel; 16. Fluid outlet; 17. Leakage detection sensor; 18. Connecting pipe; 19. Fluid interface; 20. Gas interface; 21. Flexible conductive layer; 22. Conductive busbar layer; 23. Insulating layer; 24. Insulating tube; 25. Insulating shell; 26. Ventilation channel; 27. Air hole. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] like Figure 1 and Figure 2 As shown, a 20-roll mill zoned electrical control device includes a frame 1, first intermediate rolls 2, second intermediate rolls 3, and clamping plates 4. There are four first intermediate rolls 2, diagonally arranged at the first intermediate roll 2 mounting positions on the mill. One pair is equipped with the fluid zoned electrical control first intermediate rolls 2 provided by this invention, and the other pair is equipped with ordinary first intermediate rolls 2. There are six second intermediate rolls 3, installed at the second intermediate roll 3 mounting positions on the mill, with the outer surface of the second intermediate rolls 3 in contact with the outer surface of the first intermediate rolls 2. Two work rolls 5 are mounted on the frame 1, with the outer surface of the work rolls 5 in contact with the outer surface of the first intermediate rolls 2. Each work roll 5 corresponds to two first intermediate rolls 2 and three second intermediate rolls 3. Clamping plates 4 are installed on the left and right sides of the frame 1, guiding strip 6 between the two clamping plates 4, with the outer surface of the work rolls 5 in contact with the surface of the strip 6.

[0023] The front end of the first intermediate roll 2 is provided with a positive power connector 7, which is connected to a positive power source. The rear end of the first intermediate roll 2 is provided with a negative power connector 8, which is connected to the mill joint, and a flexible collar 9 is fitted at the connection point.

[0024] The first intermediate roller 2 is the core load-bearing component of the zoned power control system. Its structural design directly affects the stability of current transmission, the control accuracy, and the equipment's resistance to wear during long-term operation.

[0025] like Figure 3As shown, the first intermediate roll 2 has a hollow structure, with three independent fluid chambers 10 arranged axially in the central region. Each fluid chamber 10 has an equal length, and the total length covers the effective rolling width of the work roll 5. The inner wall of the fluid chamber 10 has a first interface 11. The interior of the first intermediate roll 2 has three independent fluid inlet channels 12. The first interface 11 is connected to one end of the fluid inlet channel 12. The side wall of the mill joint has three fluid inlets 13. One end of the fluid inlet 13 is connected to the other end of the fluid inlet channel 12. The inner wall of the fluid chamber 10 away from the first interface 11 has a second interface 14. The interior of the first intermediate roll 2 has a one-way discharge channel. All three second interfaces 14 are connected to the fluid discharge channel 15. The side wall of the mill joint has a fluid outlet 16. The other end of the fluid discharge channel 15 is connected to the fluid outlet 16.

[0026] Each fluid chamber 10 has its first interface 11 independently controlled, while the second interface 14 of each fluid chamber 10 merges into a common fluid discharge channel 15, facilitating unified collection and circulation of the solution. This structure simplifies outlet-side sealing and piping layout while ensuring independent control of each zone.

[0027] The base material of the first intermediate roller 2 is made of a high-strength, highly conductive alloy material to withstand mechanical loads while also meeting conductivity requirements. Since most conductive media are corrosive, all inner wall surfaces in contact with the conductive media must be coated with a corrosion-resistant and wear-resistant coating, preferably a ceramic composite coating, to prevent resistance drift and particulate contamination caused by electrochemical corrosion. Insulating bushings are installed between the three fluid chambers 10 to achieve electrical isolation and prevent crosstalk between different sections of current.

[0028] Leak detection sensors are installed between adjacent fluid chambers 10. Leak detection sensors 17 are used to monitor the solution cross-contamination in real time to ensure that the three fluid chambers 10 do not cross-contact each other and maintain the independent and controllable resistance of each zone.

[0029] like Figure 4 As shown, the fluid inlet 13 has an internal thread at one end away from the fluid access channel 12, and the connecting pipe 18 has an external thread that matches the internal thread at one end. One end of the connecting pipe 18 is inserted into the fluid inlet 13 and is fixed by the external thread and the internal thread engaging. The other end of the connecting pipe 18 is provided with a fluid interface 19 and a gas interface 20. The fluid interface 19 is connected to a conductive medium tank via an injection pump and is used to introduce a conductive medium, preferably a NaCl solution. The gas interface 20 is connected to a protective gas source via a gas pressure valve and is used to introduce a protective gas, preferably argon.

[0030] like Figure 5As shown, the flexible collar 9 is an annular structure, and its inner diameter matches the diameter of the rear end of the first intermediate roll 2. It is tightly fitted with an interference fit at the connection between the first intermediate roll 2 and the mill joint. The flexible collar 9 adopts a three-layer composite structure, consisting of a flexible conductive layer 21, a conductive current-collecting layer 22, and an insulating layer 23 from the inside out.

[0031] Flexible conductive layer 21: It is in close contact with the surface of the first intermediate roller 2 and is made of flexible material, specifically conductive silicone.

[0032] Conductive bus layer 22: Covers the outside of the flexible conductive layer 21 and adopts a full-circumferential copper layer structure. Specifically, oxygen-free copper is selected and the surface of the copper layer is tin-plated to prevent copper oxidation. Copper has excellent conductivity. The full-circumferential design can ensure smooth conductive contact without dead corners. It can collect and divide the current transmitted from the flexible conductive layer 21 to avoid current concentration that could lead to local overheating, while ensuring the continuity of current transmission.

[0033] Insulation layer 23: Covers the outside of the conductive busbar layer 22 and is made of silicone rubber. Its core function is to ensure that the first working roll 5 is kept insulated from other parts of the twenty-roll mill when it is energized, to prevent current leakage to the main body of the mill, to avoid damage to the electrical and transmission components of the mill system, to ensure the safe operation of the equipment, and at the same time to prevent external debris and oil from entering the inside of the collar and affecting the conductivity.

[0034] The second intermediate roller 3 is fitted with an insulating tube 24. Preferably, the insulating tube 24 is made of high-purity quartz glass with a wall thickness of 1.5-2.0 mm, an inner diameter that is 0.8-1.0 mm larger than the outer diameter of the second intermediate roller 3, and a length that is consistent with the working section length of the second intermediate roller 3.

[0035] Both ends of the insulating tube 24 are sealed to the journal of the second intermediate roller 3 via fluororubber sealing end caps, forming a sealed insulating cavity between the insulating tube 24 and the second intermediate roller 3. Argon gas is used as a protective gas inside the insulating cavity to achieve gas insulation.

[0036] like Figure 6 As shown, an insulating shell 25 is fitted onto the outer side of the clamping plate 4. An air passage 26 is machined inside the insulating shell 25, and multiple air holes 27 are evenly distributed on the inner surface of the insulating shell 25 in a matrix arrangement. The air passage 26 is connected to the air holes 27. Argon gas is introduced into the air passage 26 and ejected through the air holes 27, forming an upward and downward convection gas film between the upper and lower clamping plates 4. This maintains a non-contact insulation between the clamping plate 4 and the strip 6, preventing current leakage through the clamping plate 4.

[0037] The present invention provides a zoned electrical control device for a 20-roll mill, which is equipped with a control system. The control system is electrically connected to the injection pump, gas pressure valve and leakage detection sensor 17 of each fluid inlet channel 12, and is used to independently adjust the capacity of NaCl solution in each fluid chamber 10.

[0038] Based on the above-mentioned zonal power control device for a 20-roll mill, the present invention provides a zonal power control method for a 20-roll mill, specifically including the following steps: S1. Preliminary preparation and equipment installation: Install the fluid zone control electric first intermediate roll 2 at the upper left and lower right first intermediate roll 2 installation positions of the 20-roll mill, and install the ordinary first intermediate roll 2 at the upper right and lower left.

[0039] The flexible collar 9 is tightly fitted at the connection between the rear end of the first intermediate roll 2 and the mill joint to ensure that the flexible conductive layer 21 is completely in contact with the roll surface without gaps.

[0040] An insulating tube 24 is fitted onto the outside of the second intermediate roller 3, a sealed end cap is installed, and an argon gas pipeline is connected.

[0041] An insulating shell 25 is fitted onto the clamping plate 4 and connected to an argon gas pipeline.

[0042] Connect the NaCl solution injection line, the NaCl solution return line, and the argon gas delivery line, and connect the leak detection sensor 17 to the control system.

[0043] S2. Medium Injection and Initial Parameter Setting: Start the injection pump and inject NaCl solution into the three fluid chambers 10 through the independent fluid inlet channel 12. Set the initial solution capacity of the left, middle, and right fluid chambers 10 according to the pre-calibrated current-capacity curve.

[0044] Open the argon valve and introduce argon gas into the insulation cavity of the second intermediate roller 3 and the ventilation channel 26 of the clamping plate 4.

[0045] Start the leakage detection sensor 17 and run it for a period of time to confirm that there is no cross-contamination or leakage in the three fluid chambers 10. Use a megohmmeter to test the insulation resistance of each insulating component.

[0046] S3. Precise Control of Zoned Current: The control system uses a PID algorithm to independently adjust the NaCl solution volume in each fluid chamber 10, achieving closed-loop control of the zoned current. When it is necessary to increase the current in a certain section, the control system sends a command to open the solenoid valve of the corresponding fluid interface 19, and controls the injection pump to replenish NaCl solution to the target fluid chamber 10, thereby increasing the effective conductive cross-sectional area, reducing the regional resistance, and thus increasing the current in that section.

[0047] When it is necessary to reduce the current in a certain section, the control system sends a command to introduce argon gas into the target fluid chamber 10, push the solution to the fluid discharge channel 15, and enter the common return chamber for recovery, thereby reducing the effective conductive cross-sectional area, increasing the area resistance, and thus reducing the current in that section.

[0048] The control system collects current signals from each zone and signals from the leakage detection sensor 17 in real time, and fine-tunes the solution injection volume and argon pressure in real time according to the preset current-capacity calibration curve.

[0049] S4. Real-time maintenance during the rolling process: Continuously monitor argon pressure and flow rate to ensure normal argon flow and reliable insulation in the insulation cavity and ventilation channel 26.

[0050] The NaCl solution is collected uniformly through the common fluid discharge channel 15, filtered, and reused. The solution concentration is tested periodically.

[0051] When the leakage detection sensor 17 detects inter-section liquid cross-contamination, the injection of conductive medium into the fluid chamber 10 is immediately stopped, the gas interface 20 is switched to introduce argon gas to purge the solution, and then the machine is stopped to replace the insulating bushing and re-seal and calibrate.

[0052] When a current fluctuation is detected, immediately check the fit of the flexible collar 9. If it is loose, reinstall it. At the same time, adjust the solution capacity and argon pressure of the corresponding fluid chamber 10 until the current returns to stability.

[0053] S5. Rolling End and Shutdown: After rolling is completed, argon gas is first introduced into all fluid chambers 10 to purge the NaCl solution, and the machine is run for a period of time.

[0054] Gradually reduce the power supply output current until the current is zero, then disconnect the positive and negative power connectors 8.

[0055] Close the argon valve and solution delivery system, purge all pipelines with argon gas, and remove any residual medium.

[0056] Disassemble the flexible collar 9 and the quartz insulating tube 24, clean the oil and impurities on the surface, and check for any damage.

[0057] Record the current parameters, plate shape data, and equipment operating status of each zone during this rolling process, and then complete the shutdown.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A zoned power control device for a 20-roll mill, characterized in that: The machine includes a frame, a first intermediate roll, a second intermediate roll, and a clamping plate. The first intermediate roll, the second intermediate roll, and the clamping plate are all connected to the frame. The outer surface of the first intermediate roll is in contact with the outer surface of the second intermediate roll. A work roll is provided on the frame, and the outer surface of the work roll is in contact with the outer surface of the first intermediate roll. A strip is provided between the clamping plates, and the outer surface of the work roll is in contact with the strip. A positive power connector is provided at the front end of the first intermediate roll, and a negative power connector is provided at the rear end of the first intermediate roll. The negative power connector is connected to the mill joint, and a flexible collar is provided at the connection.

2. The zonal electrical control device for a 20-roll mill according to claim 1, characterized in that: The first intermediate roll has a fluid chamber inside, and a first interface is provided on the side wall of the fluid chamber. The first intermediate roll has a fluid inlet channel inside, and the first interface is connected to one end of the fluid inlet channel. The side wall of the mill joint has a fluid inlet, and the other end of the fluid inlet channel is connected to the fluid inlet. The side wall of the fluid chamber has a second interface, and the first intermediate roll has a fluid outlet channel inside, and the second interface is connected to one end of the fluid outlet channel. The side wall of the mill joint has a fluid outlet, and the other end of the fluid outlet channel is connected to the fluid outlet.

3. The partitioned power control device for a 20-roll mill according to claim 2, characterized in that: A leak detection sensor is provided between adjacent fluid chambers. The leak detection sensor is used to ensure that the three fluid chambers do not communicate with each other and to maintain the independent and controllable resistance of each section.

4. The zonal power control device for a 20-roll mill according to claim 3, characterized in that: A connecting pipe is connected to the fluid inlet, and a fluid interface and a gas interface are respectively provided at the other end of the connecting pipe. The fluid interface is used to introduce a conductive medium, and the gas interface is used to introduce a protective gas.

5. The zonal electrical control device for a 20-roll mill according to claim 4, characterized in that: The flexible collar includes a flexible conductive layer disposed on the outer surface of the first intermediate roller. A conductive busbar is disposed outside the flexible conductive layer to avoid current concentration and ensure continuous current transmission. An insulating layer is disposed outside the conductive busbar to maintain insulation and prevent power leakage.

6. The zonal power control device for a 20-roll mill according to claim 5, characterized in that: An insulating tube is provided on the outside of the second intermediate roller, and an insulating cavity is formed between the insulating tube and the second intermediate roller. Protective gas is introduced into the insulating cavity.

7. The zonal power control device for a 20-roll mill according to claim 6, characterized in that: An insulating shell is provided on the outside of the clamping plate. An air passage is provided inside the insulating shell. An air hole is provided on the outer surface of the insulating shell. The air passage is connected to the air hole. Protective gas is introduced into the air passage and ejected through the air hole to form an upper and lower convection air film.

8. A method for zoned power control of a 20-roll mill, based on the device described in claim 7, characterized in that, Includes the following steps: S1: Install the fluid partition control first intermediate roll and the ordinary first intermediate roll diagonally at the first intermediate roll installation position of the twenty-roll mill, assemble the flexible collar, the second intermediate roll and the clamping plate, and connect the conductive medium conveying pipeline and the protective gas conveying pipeline. S2: Inject conductive medium into the three fluid access channels respectively, set the initial capacity of each fluid chamber according to the current-capacity calibration curve, and introduce protective gas into the insulation chamber and ventilation channel to perform system insulation and leakage detection; S3: The control system independently adjusts the capacity of the conductive medium in each fluid chamber and performs calibration to maintain the stability of the current in each zone; S4: Continuously monitor insulation status, dielectric circulation status and current stability, and promptly handle inter-section liquid penetration and abnormal current fluctuations. S5: First, introduce protective gas into each fluid chamber to purge the conductive medium, gradually reduce the current to zero, then disconnect the power supply, purge the residual medium, and clean the equipment.

9. A method for zoned power control of a 20-roll mill according to claim 8, characterized in that: In step S3, when the current is increased, the injection pump is controlled to replenish the conductive medium to the target fluid chamber; when the current is decreased, protective gas is introduced into the target fluid chamber to push out the conductive medium.

10. A method for zoned power control of a 20-roll mill according to claim 9, characterized in that: In step S4, when inter-segment fluid leakage is detected, the injection of conductive medium into the fluid chamber is immediately stopped, and protective gas is introduced to purge the conductive medium before resealing and calibration. When current fluctuation is detected, the fit of the flexible collar is checked and the capacity of the conductive medium and the pressure of the protective gas are adjusted.

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