Eddy current protection system of channel-type induction heating tundish

Abstract

An eddy current protection system of a channel-type induction heating tundish, comprising the channel-type induction heating tundish, an induction heating module, an eddy current protection module, a cooling module, a detection module, a structure parameter acquisition module and a protection control module, wherein the channel-type induction heating tundish comprises quasi-circular through holes (5) for induction heaters to pass through and eddy current partition slots (6). The system can block a large reactive eddy current generated on a tundish shell and induction heater shells in the induction heating process, reduce the heat of the shells, avoid severe eddy current heating that reduces the working intensity and structural strength of the tundish, determine the specific arrangement position of a temperature sensor and an adjusting method of the eddy current protection system, effectively utilize cooling energy to avoid energy waste, and test the device operation safety in time.

Description

An eddy current protection system for channel-type induction heating tundish Technical Field

[0001] The invention relates to the technical field of continuous casting tundish metallurgy, in particular to an eddy current protection system for a channel-type induction heating tundish. Background Art

[0002] The superheat of the molten steel in the tundish is one of the key process parameters for ensuring continuous casting output and ingot quality. Low superheat and constant temperature casting not only increases casting speed, reduces breakouts, and improves the internal and external quality of the ingot, but also reduces tapping temperatures and increases the life of the furnace lining. In production, the most widely used method is tundish channel induction heating. The working principle of tundish channel electromagnetic induction heating is based on the principle of electromagnetic induction.

[0003] Chinese Patent Publication No.: CN219093621U discloses a continuous casting induction heating tundish, which includes a casting area, an impact zone, a left channel and a right channel, wherein the left channel connects the casting area and the impact zone on the left side, and the left channel forms a length L1; the right channel connects the casting area and the impact zone on the right side, and the right channel forms a length L2, L1=L2, or L1≠L2; the left channel and the right channel form an eight-shaped structure open to the casting area, and external heat sources are respectively arranged around the left channel and the right channel. The invention provides an external heat source around the left and right channels to compensate for the heat loss during the continuous casting process, thereby achieving low superheat constant temperature casting during the continuous casting process. At the same time, the molten steel flowing through the channel is pinched to squeeze out inclusions and oxygen in the molten steel, thereby improving the surface and internal quality of the continuous casting billet. The coil is arranged horizontally below the channel, which not only helps to reduce the dead zone ratio, improve the flow consistency of the billet, and improve the surface quality, but also helps to compensate for the heat loss of the tundish, improve the temperature consistency, and improve the internal quality of the billet and the stability of the final product. It can be seen that the above technical solution completes the heating of the tundish by designing the tundish structure, but cannot block the large reactive eddy currents generated on the tundish shell and the induction heater shell during the induction heating process, nor can it determine the adjustment method of the eddy current protection system according to the actual temperature of the induction heating tundish detected, the actual cooling air volume and coolant flow of the cooling module, and the actual working current and current frequency of the induction heating module. It cannot ensure the working intensity and structural strength of the tundish continuous casting, resulting in a waste of cooling energy.

[0004] Summary of the Invention

[0005] To this end, the present invention provides an eddy current protection system for a channel-type induction heating tundish, which is used to overcome the problem in the prior art that the tundish shell and the induction heater protection tube are heated due to reactive eddy currents generated during electromagnetic heating, resulting in a decrease in the strength of the tundish overheating structure.

[0006] To achieve the above objectives, the present invention provides an eddy current protection system for a channel-type induction heating tundish, comprising:

[0007] A channel-type induction heating tundish comprising an injection zone, a casting zone, and a steel flow channel connecting the injection zone and the casting zone, wherein the tundish shell is provided with a quasi-circular through-hole for passage of the induction heater, an eddy current isolating groove extending through the quasi-circular through-hole to the edge of the tundish shell, and an insulating material gasket filled in the eddy current isolating groove, wherein the eddy current isolating groove and the quasi-circular through-hole are both provided between the injection zone and the casting zone;

[0008] an induction heating module connected to the channel-type induction heating tundish and having an axis of its induction heater coil passing through the quasi-circular through-hole, for heating the molten steel in the steel flow channel through a magnetic field generated by the induction heater coil in an alternating current;

[0009] An eddy current protection module is connected to the induction heating module and includes a protection tube arranged outside the induction heater coil, and an open groove is opened on the side of the protection tube and penetrates the surface of the protection tube;

[0010] a cooling module connected to the induction heating module, comprising an air cooling unit for cooling the heat radiation of the high-temperature molten steel and a liquid cooling unit for cooling the eddy current heat of the induction heater coil and its core;

[0011] a detection module connected to the channel-type induction heating tundish, the induction heating module, and the eddy current protection module, and configured to obtain the temperature of the tundish shell, the temperature of the protection cylinder, the actual operating parameters of the induction heater, and the actual operating parameters of the cooling module;

[0012] a structural parameter acquisition module for acquiring the ambient temperature of the channel-type induction heating tundish, the specific heat capacity of the coolant of the liquid cooling unit, the cross-sectional area of ​​the coolant channel of the liquid cooling unit, the inner diameter of the steel flow channel, and the electrical parameters of the induction heater;

[0013] a protection control module, connected to the detection module, the cooling module, and the structural parameter acquisition module, respectively, for determining the eddy current distribution and the total Joule heat on the protective cylinder and the tundish shell according to the structural and physical parameters of the induction heater, the tundish shell, and the protective cylinder, determining the operating parameters of the induction heater and the cooling module according to the total Joule heat, and adjusting the operating parameters of the cooling module and the induction heater according to the difference between the temperature measurement value detected by the detection module and the preset value;

[0014] The operating parameters of the cooling module include the cooling air volume and the flow rate of the coolant of the air cooling unit, and the operating parameters of the induction heater include the heating current size and current frequency of the induction heater coil.

[0015] Furthermore, the protection control module establishes an electromagnetic field model and an eddy current distribution model according to the structure and physical parameters of the eddy current protection system to calculate the total amount of Joule heat on the protection cylinder, the tundish shell and the air cooling unit of the induction heating module at various working currents and current frequencies;

[0016] The protection control module determines the temperature distribution on the protection tube and the tundish shell when thermally balanced according to the total Joule heat of the protection tube and the tundish shell to determine the arrangement position of the temperature sensor of the detection module.

[0017] Furthermore, the protection control module determines the cooling air volume and coolant flow rate according to the operating current and current frequency of the induction heating module, and determines the adjustment mode of the eddy current protection system according to the actually detected cooling air volume and coolant flow rate;

[0018] The adjustment method includes adjusting the working current, current frequency, cooling air volume, and coolant flow of the induction heating module.

[0019] Furthermore, the arrangement positions of the temperature sensors include the highest temperature position on the tundish shell, the lowest temperature position on the tundish shell, and the highest temperature position on the protective tube;

[0020] The highest temperature position is the center position of the preset circular area on the surface of the structure corresponding to the maximum Joule heat weight corresponding to the total Joule heat calculated in the preset circular area, and the lowest temperature position is the center position of the preset circular area on the surface of the structure corresponding to the minimum Joule heat weight corresponding to the total Joule heat calculated in the preset circular area;

[0021] The radius of the preset circular area is not less than 10 cm.

[0022] Furthermore, the protection control module determines an adjustment mode for the working parameters of the induction heater according to the unit temperature rise value of the highest temperature position on the tundish shell actually detected;

[0023] If the unit temperature rise value is higher than the preset temperature rise value, the protection control module determines to reduce the heating current of the induction heater or reduce the current frequency of the induction heater.

[0024] Furthermore, the protection control module determines an adjustment range of the working parameters of the induction heater according to a difference between the actually detected temperature at the highest temperature position on the tundish shell and the temperature at the lowest temperature position on the tundish shell;

[0025] The difference is inversely proportional to the adjustment amplitude of the operating parameter.

[0026] Furthermore, the protection control module calculates the eddy current heating temperature rise value of the molten steel according to the unit temperature rise value of the outer bottom surface of the tundish shell in the casting area, and determines the required temperature rise adjustment value of the molten steel according to the eddy current heating temperature rise value of the molten steel.

[0027] Furthermore, the protection control module establishes an electromagnetic field model and an eddy current distribution model according to the structure and physical parameters of the eddy current protection system, including:

[0028] A three-dimensional equivalent model of the tundish shell is established based on the structural positional relationship and dimensional data of each part of the tundish shell, and an equivalent induced electromagnetic field model and eddy current distribution model of the tundish are established based on the material conductivity of each part of the tundish shell, the specific arrangement position of the induction heater on the tundish shell, the number of coil turns, the operating current, and the current frequency;

[0029] A three-dimensional equivalent model of the protective tube is established based on the structural position relationship and dimensional data of the protective tube, and an equivalent induced electromagnetic field model and eddy current distribution model of the protective tube are established based on the material conductivity of the protective tube and the specific layout position, number of coil turns, working current and current frequency of the induction heater on the protective tube.

[0030] Furthermore, the operating parameter adjustment range includes a current adjustment amount ΔI and a frequency adjustment amount Δf;

[0031] If you choose to adjust the heating current of the induction heater, the current adjustment amount ΔI is determined by the following formula:

[0032] Where, I is the working current value of the induction heater before adjustment, S is the bottom area of ​​the tundish shell, L is the T is the straight-line distance between the highest temperature position on the tundish shell and the lowest temperature position on the tundish shell, ΔT is the difference between the highest temperature position and the lowest temperature position on the tundish shell, Th is the ambient temperature;

[0033] If you choose to adjust the current frequency of the induction heater, the frequency adjustment amount Δf is determined by the following formula:

[0034] Where f is the current frequency value of the induction heater before adjustment, S is the bottom area of ​​the tundish shell, and λ is the frequency conversion coefficient, 1≤λ≤1.3.

[0035] Furthermore, the required temperature rise adjustment value is the temperature value of the molten steel flowing into the casting area through the heated flow steel channel of the induction heater. The required temperature rise adjustment value T q Determined by the following formula: T q =T Q -T w ;

[0036] Where, T Q is the required temperature of the molten steel flowing out of the casting area, T wk is the unit temperature rise value of the outer bottom surface of the tundish shell, T w =T wk ×η, η is the conductivity conversion coefficient.

[0037] Compared with the prior art, the beneficial effect of the present invention lies in that, by providing eddy current isolation grooves on the tundish shell and the induction heater shell and filling insulating material gaskets in the eddy current isolation grooves, the present invention can block the large reactive eddy currents generated on the tundish shell and the induction heater shell during the induction heating process, reduce the heat generation of the shell, and avoid the eddy current heat generation from seriously reducing the working strength and structural strength of the tundish. In addition, by providing flange structures at both ends of the eddy current isolation grooves for fastening, the structural stability of the tundish shell is effectively improved, and the structural strength of the tundish is further effectively guaranteed.

[0038] Furthermore, the eddy current protection system of the present invention adopts the channel-type induction heating tundish structure of the present invention and detects, calculates and monitors various parameters during the operation of the tundish. On the one hand, it can perform eddy current isolation treatment on the tundish shell, thereby avoiding the generation of large eddy current circulation in the tundish shell and reducing the heat generation of the tundish shell; on the other hand, the present invention establishes an electromagnetic field model and an eddy current distribution model according to the structure and physical parameters of the eddy current protection system to calculate the total Joule heat of the protective cylinder of the induction heating module, the tundish shell and the air cooling unit under various working currents and current frequencies, and determines the layout position of the temperature sensor, thereby improving the protection and warning efficiency of the eddy current protection system and effectively ensuring the working intensity and structural strength of the tundish continuous casting.

[0039] Furthermore, the eddy current protection system of the present invention determines the specific layout position of the temperature sensor and determines the adjustment method of the eddy current protection system according to the detected actual temperature of the induction heating ladle, the actual cooling air volume and coolant flow of the cooling module, and the actual working current and current frequency of the induction heating module, thereby effectively utilizing cooling energy to avoid energy waste, and at the same time being able to timely detect the safety of equipment operation, thereby enhancing the structural stability of the ladle.

[0040] Furthermore, the present invention can determine a method for adjusting the operating parameters of the induction heater based on the unit temperature rise value of the highest temperature position actually detected on the tundish shell. Since the highest temperature position on the tundish shell can reflect the maximum impact of the eddy current effect on the tundish, the eddy current tolerance of the tundish can be accurately judged in a timely manner by the unit temperature rise value of the highest temperature position on the tundish shell, and corresponding adjustments can be taken in a timely manner.

[0041] Furthermore, the present invention determines the adjustment range of the operating parameters of the induction heater based on the difference between the temperature at the highest temperature position on the tundish shell and the temperature at the lowest temperature position on the tundish shell that are actually detected. Since the difference between the temperature at the highest temperature position on the tundish shell and the temperature at the lowest temperature position on the tundish shell can represent the heat exchange capability of the tundish shell itself and its ability to withstand the temperature of the molten steel heated by the induction heater, determining the adjustment range of the operating parameters of the induction heater based on the difference can, on the one hand, maximize the normal operation of the tundish, and on the other hand, reduce the waste of electric energy of the induction heater and improve energy utilization efficiency by accurately calculating the adjustment range of the operating parameters.

[0042] Furthermore, the present invention characterizes the temperature rise of the molten steel in the casting area caused by eddy current heating in the casting area, i.e., the eddy current heating temperature rise value of the molten steel, by the unit temperature rise value detected by the temperature sensor arranged on the bottom surface of the tundish shell, thereby judging the required temperature rise value of the molten steel heated by the induction heater, which can improve the heating efficiency of the induction heater, maximize the use of eddy currents, and achieve the effect of saving energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] FIG1 is a schematic diagram of a channel-type induction heating tundish according to an embodiment of the present invention;

[0044] FIG2 is a schematic structural diagram of the eddy current isolation groove of the channel-type induction heating tundish according to an embodiment of the present invention;

[0045] FIG3 is a structural block diagram of an eddy current protection system according to an embodiment of the present invention;

[0046] FIG4 is a schematic diagram of a cooling module according to an embodiment of the present invention;

[0047] FIG5 is a schematic diagram of eddy current distribution of a protective tube without grooves according to an embodiment of the present invention;

[0048] FIG6 is a schematic diagram of eddy current distribution in a protective tube with open slots according to an embodiment of the present invention;

[0049] FIG7 is a schematic diagram of eddy current distribution of a tundish shell without eddy current isolation grooves according to an embodiment of the present invention;

[0050] FIG8 is a schematic diagram of eddy current distribution of a tundish shell provided with eddy current isolation grooves according to an embodiment of the present invention;

[0051] FIG9 is a schematic diagram of the side structure of an induction heater according to an embodiment of the present invention;

[0052] Among them: 1, injection area; 2, casting area; 3, steel flow channel; 4, induction heater; 5, quasi-circular through hole; 6, eddy current isolation groove; 7, insulating material gasket; 8, flange end; 9, induction heater coil; 10, protective tube; 11, open groove; 12, non-steel bearing area; 13, the highest temperature position on the protective tube; 14, protective tube opening flange; 15, insulating connecting bolts; 16, upper air duct; 17, lower air duct; 18, inverted U-shaped upper iron core; 19, rectangular cylindrical yoke; 20, bottom surface of the ladle shell; 21, side wall; 22, the highest temperature position on the ladle shell; 23, the lowest temperature position on the ladle shell. DETAILED DESCRIPTION

[0053] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0054] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0055] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside", and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0056] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0057] Please refer to Figures 1 and 2, Figure 1 is a schematic diagram of a channel-type induction heating tundish according to an embodiment of the present invention, and Figure 2 is a structural schematic diagram of an eddy current isolation groove of a channel-type induction heating tundish according to an embodiment of the present invention. An embodiment of the present invention provides a channel-type induction heating tundish, comprising an injection area 1, a casting area 2, a steel flow channel 3, a non-steel-bearing area 12, a quasi-circular through hole 5, an eddy current isolation groove 6 and an insulating material gasket 7. The injection area 1, the casting area 2 and the non-steel-bearing area 12 are separated by the side wall of the tundish.

[0058] The tundish shell is provided with a quasi-circular through hole 5 for the induction heater 4 to pass through, an eddy current isolation groove 6 that penetrates the quasi-circular through hole 5 and extends to the edge of the tundish shell, and an insulating material gasket 7 filled in the eddy current isolation groove 6;

[0059] Continuing to refer to FIG1 and FIG2 , the eddy current isolation groove 6 and the quasi-circular through hole 5 are both provided in the non-steel-bearing area 12 between the injection area 1 and the casting area 2, and the steel flow channel 3 passes through the non-steel-bearing area 12. Preferably, the voids in the non-steel-bearing area 12 are filled with insulating refractory material.

[0060] Specifically, the insulating material gasket 7 can be made of ceramic, quartz, or other insulating high-temperature compounds. The heat-resistant temperature of the insulating material is not lower than the heat-resistant temperature of the tundish shell. The width of the eddy current isolation groove 6 is between 10mm and 30mm.

[0061] Specifically, the tundish shell is provided with a main seam flange connection portion for fastening and connecting the insulating material gasket 7 and the two sides of the eddy current isolation groove 6. The main seam flange connection portion includes two flange ends 8 located on both sides of the eddy current isolation groove and connecting bolts for connecting the two flange ends.

[0062] Wherein, the material of the connecting bolts is insulating material.

[0063] Specifically, the cross-sectional shape of the steel flow channel 3 is circular, and the inner diameter of the steel flow channel 3 is 85 mm to 175 mm.

[0064] In practice, when designing the inner diameter of the steel flow channel, it is considered that the molten steel flows from the injection area through the steel flow channel into the casting area. If the inner diameter of the steel flow channel is too small, the molten steel circulation efficiency will be too low. If the inner diameter of the steel flow channel is too large, the resistance value of the molten steel in the channel will be reduced and it will not be effectively heated by the induction heater. The inner diameter of the steel flow channel is set to between 85mm and 175mm, which not only ensures the circulation efficiency of the molten steel in the channel, but also ensures that the resistance value of the molten steel in the channel is within the effective heating range of the induction heater.

[0065] Specifically, the bottom shell material of the tundish shell has an electrical conductivity of less than 15 MS / m to reduce reactive eddy currents in the tundish shell. Bottom shell materials include stainless steel and non-magnetic manganese steel with electrical conductivities of 1 to 15 MS / m. For example, in Figure 2 , the bottom surface 20 of the tundish shell is made of a material with an electrical conductivity of less than 15 MS / m. Preferably, the sidewalls 21 of the tundish shell near the eddy current isolation slots 6 are also made of a material with an electrical conductivity of less than 15 MS / m to better block reactive eddy currents.

[0066] In a specific embodiment, as shown in Figures 1 and 2, the tundish used is an eight-shaped structure using two induction heaters 4. The injection area 1 is used to pour molten steel. The molten steel enters the casting area 2 through the symmetrically arranged flow channels 3 and is heated by the induction heater 4 set at the position of the circular through hole 5 in the flow channels 3.

[0067] It's understood that the operating principle of channel-type electromagnetic induction heating is based on the principle of electromagnetic induction. When a medium-frequency current is fed into the induction heater coil, the alternating current establishes a primary magnetic flux in the closed magnetic circuit of the heater core. This alternating magnetic flux generates an induced potential in the molten steel within the flow channel connected to the core windings. Because the molten steel flowing through the flow channel is conductive, an induced current forms within it. This induced current generates Joule heat in the molten steel, thereby achieving the desired insulation and heating effect. This induced potential, and thus induced current, is generated within all conductive metals connected to the core windings. This induced potential is not only generated within the molten steel, but also within other conductive metal components or structural elements connected to the core windings, such as the tundish shell, the induction heater protective tube, and the cooling duct. Eddy current heating of the tundish's structural components can reduce operating intensity, thereby impacting equipment safety. Therefore, in this embodiment, the tundish shell is grooved to block the large reactive eddy currents generated on the tundish shell and the induction heater shell during induction heating, reduce the heat generation of the shell, and avoid the eddy current heat generation from seriously reducing the working strength and structural strength of the tundish. In addition, by arranging flange structures at both ends of the eddy current isolation groove for fastening, the structural stability of the tundish shell is effectively improved, and the structural strength of the tundish is further effectively guaranteed.

[0068] Please refer to Figures 1, 2, 3 and 9, which are structural block diagrams of an eddy current protection system according to an embodiment of the present invention. The embodiment of the present invention provides an eddy current protection system for a channel-type induction heating tundish, comprising:

[0069] A channel-type induction heating tundish comprises an injection zone 1, a casting zone 2, and a steel flow channel 3 connecting the injection zone and the casting zone. The tundish shell is provided with a substantially circular through-hole 5 for passage of the induction heater, an eddy current isolation groove 6 extending through the substantially circular through-hole 5 to the edge of the tundish shell, and an insulating material gasket 7 filled in the eddy current isolation groove 6. The eddy current isolation groove 6 and the substantially circular through-hole 5 are both provided between the injection zone 1 and the casting zone 2.

[0070] an induction heating module connected to the channel-type induction heating tundish and having an axis of its induction heater coil 9 passing through the quasi-circular through-hole 5, for heating the molten steel in the steel flow channel 3 through the magnetic field generated by the induction heater coil 9 in the alternating current;

[0071] An eddy current protection module is connected to the induction heating module and includes a protection tube 10 disposed outside the induction heater coil, with an open groove 11 penetrating the surface of the protection tube being provided on the side of the protection tube 10;

[0072] a cooling module connected to the induction heating module, comprising an air cooling unit for cooling the heat radiation of the high-temperature molten steel and a liquid cooling unit for cooling the eddy current heat of the induction heater coil and its core;

[0073] a detection module connected to the channel-type induction heating tundish, the induction heating module, and the eddy current protection module, and configured to obtain the temperature of the tundish shell, the temperature of the protection cylinder 10, the actual operating parameters of the induction heater 4, and the actual operating parameters of the cooling module;

[0074] a structural parameter acquisition module for acquiring the ambient temperature of the channel-type induction heating tundish, the specific heat capacity of the coolant of the liquid cooling unit, the cross-sectional area of ​​the coolant channel of the liquid cooling unit, the inner diameter of the steel flow channel 3, and the electrical parameters of the induction heater 4;

[0075] a protection control module, connected to the detection module, the cooling module, and the structural parameter acquisition module, respectively, for determining the eddy current distribution and the total Joule heat on the protective cylinder and the tundish shell according to the structural and physical parameters of the induction heater 4, the tundish shell, and the protective cylinder 10, determining the operating parameters of the induction heater and the cooling module according to the total Joule heat, and adjusting the operating parameters of the cooling module and the induction heater according to the difference between the temperature measurement value detected by the detection module and the preset value;

[0076] The operating parameters of the cooling module include the cooling air volume and the flow rate of the coolant of the air cooling unit, and the operating parameters of the induction heater include the heating current size and current frequency of the induction heater coil.

[0077] In one embodiment, the channel-type induction heating tundish further comprises:

[0078] a non-steel-bearing zone 12, which is arranged between the injection zone 1 and the casting zone 2. The injection zone 1, the casting zone 2 and the non-steel-bearing zone 12 are separated by the wall of the tundish shell, and the non-steel-bearing zone 12 does not carry molten steel;

[0079] The quasi-circular through hole 5 , the eddy current isolation groove 6 and the induction heating module are all arranged in the non-steel-bearing area 12 , and the steel flow channel 3 passes through the non-steel-bearing area.

[0080] Specifically, the protection tube 10 includes a protection tube shell, a fire-resistant insulation material filled between the protection tube shell and the induction heater coil, and an insulation material filled in the open slot 11;

[0081] The slot size of the opening slot 11 is 10 mm to 30 mm.

[0082] In one embodiment, as shown in Figure 9, the induction heater of the induction heating module consists of two parts, including: a movable inverted U-shaped upper core 18 and a rectangular prism yoke 19 fixed to the bottom of the intermediate shell. The movable inverted U-shaped upper core 18 is composed of a cylindrical core that passes through the induction coil and a rectangular prism core connected to the upper end of the cylindrical core, and the induction coil is wound around the outside of the cylindrical core. The movable inverted U-shaped upper core 18 passes through the circular through hole 5 in the intermediate shell and is combined with the rectangular prism yoke 19 fixed to the bottom of the intermediate shell to form a complete induction heater with a closed magnetic circuit.

[0083] It is understandable that the iron core for winding the induction coil adopts a cylindrical design, which has the following advantages: the solenoid coil wound on the cylindrical iron core has no corners, thereby maximizing the space utilization of the coil, which is conducive to increasing the number of turns of the coil and increasing the magnetic conductivity area of ​​the iron core, thereby increasing the induced magnetic flux in the closed iron core; it is conducive to reducing the volume of the inductor, reducing the space occupied in the ladle, and reducing or even not reducing the original steel-bearing capacity of the ladle, which is particularly important for adding a channel-type induction heater to the existing ladle; the pressure loss of the cooling medium through the coil is greatly reduced and the residence time is also greatly shortened, which is conducive to improving the cooling effect of the liquid cooling unit and also conducive to reducing the capacity and volume of the cooling module; the induction heater coil has no corners, which causes little damage to the insulation of the induction heater coil, which is conducive to improving the insulation grade and service life; reducing the difficulty of coil production, which is conducive to improving production quality, efficiency and reducing costs; and it is conducive to reducing the maintenance workload of the steel plant.

[0084] In one embodiment, as shown in FIG9 , the induction heater in the eddy current protection module is provided with a protective tube 10, and the open groove 11 is located on the side of the cylindrical iron core of the induction heater close to the flow steel channel. The open groove 11 runs through the upper and lower ends of the protective tube, and the upper end of the protective tube 10 at 1 / 5 to 1 / 4 of the total length is half-cut off, leaving a gap to connect with the upper air duct of the induction heater.

[0085] It is understandable that the movable inverted U-shaped upper iron core 18 passes through the protective tube 10 and is installed on the quasi-circular through hole 5, and is combined with the rectangular cylindrical yoke 19 fixed to the bottom of the package to form a closed magnetic circuit. Therefore, the induction heater coil is placed in the middle of the protective tube 10, and the protective tube 10 plays a good protective role for the coil of the induction heater. By providing an open groove 11 that passes through the upper and lower ends of the protective tube on the protective tube 10, and filling the groove and the space between the induction coil and the inner wall of the protective tube 10 with insulating refractory material, the groove destroys the closed structure of the protective tube and the eddy current circuit on the protective tube. The present invention uses an insulating ceramic spacer placed in the middle of the protective tube opening groove 11 and reinforces the structure through the protective tube opening flange 14 and insulating connecting bolts 15, which can take into account both reducing eddy currents and ensuring structural strength.

[0086] Please refer to Figures 5 and 6. The grayscale of the arrows in Figure 5 indicates that the Joule heat generated per unit area of ​​the protective tube side wall is 700kJA / m 2 Up to 1000kJA / m 2 The grayscale of the arrows in Figure 6, from light to dark, indicates that the Joule heat generated per unit area of ​​the protective tube side wall is 400kJA / m 2 Up to 100kJA / m 2It can be seen that after the opening slots 11 are set on the protective tube 10, the protective tube 10 is affected by the magnetic field of the induction heater, and the large reactive eddy current generated is blocked by the opening slots 11, which reduces the heating of the protective tube (the Joule heat generated is reduced from 1000kJA / m 2 Reduced to a maximum of 400kJA / m 2 ), thereby reducing the temperature of the protective tube.

[0087] In one embodiment, as shown in FIG2 , the width of the eddy current isolating groove provided at the bottom of the intermediate shell is between 10 mm and 30 mm, and the intermediate shell is provided with a main seam flange connection portion for fastening and connecting an insulating material gasket 7 and the two sides of the eddy current isolating groove 6. The main seam flange connection portion includes two flange ends located on both sides of the eddy current isolating groove 6 and connecting bolts for connecting the two flange ends. The material of the connecting bolts is an insulating material, including tetrafluoroethylene, polyimide, silicon carbide, and alumina.

[0088] Preferably, the quasi-circular through hole 5 and the connection between the quasi-circular through hole 5 and the eddy current isolation groove 6 are rounded by R60-100mm, the cross-section of the flow steel channel is circular, and the inner diameter of the flow steel channel is 85mm-175mm;

[0089] Preferably, the electrical conductivity of the bottom shell material of the tundish shell is lower than 15MS / m to reduce the reactive eddy current of the tundish shell and the protective cylinder; the bottom shell material includes stainless steel and non-magnetic manganese steel with an electrical conductivity of 1-15MS / m.

[0090] It can be understood that, referring to FIG7 and FIG8 , FIG7 is a schematic diagram of eddy current distribution of a tundish shell without eddy current barrier grooves according to an embodiment of the present invention, and FIG8 is a schematic diagram of eddy current distribution of a tundish shell with eddy current barrier grooves according to an embodiment of the present invention. It can be seen that, in the implementation in which the eddy current barrier grooves are not provided on the tundish shell, the tundish shell is affected by the magnetic field of the induction heater, generating large reactive eddy currents. After the eddy current barrier grooves are provided on the tundish shell, most of the eddy currents are blocked by the eddy current barrier grooves, reducing the heat generation of the shell, thereby lowering the shell temperature.

[0091] However, since the eddy current isolation groove is provided on the tundish shell, the structural strength of the tundish shell is reduced. Therefore, the eddy current isolation groove position is tightened and reinforced. At this time, if ordinary metal bolts are used for tightening and reinforcing, the tundish shell will continue to be affected by the induction heater to generate large reactive eddy currents. Therefore, the bolts used for tightening and reinforcing are selected from insulating materials.

[0092] In one embodiment, the ambient temperature of the channel-type induction heating tundish, the specific heat capacity of the coolant of the liquid-cooling unit, the cross-sectional area of ​​the coolant channel of the liquid-cooling unit, the inner diameter of the steel flow channel, and the electrical parameters of the induction heater are obtained through a structural parameter acquisition module, and the temperature of the tundish shell, the temperature of the protective cylinder, the actual working parameters of the induction heater, and the actual working parameters of the cooling module are obtained using a detection module; it can be known that the electrical parameters include rated voltage, rated current, and current frequency; the working parameters of the induction heater include heating time and heater power consumption; the working parameters of the cooling module include upwind air volume, downwind air volume, and coolant temperature; the actual working parameters refer to the measured values ​​actually detected.

[0093] Specifically, the protection control module uses the above parameters to determine the layout positions of the temperature sensors on the protection tube and the tundish shell, as well as the eddy current distribution and the total Joule heat on the protection tube and the tundish shell, and determines the working parameters of the induction heater and the cooling module according to the total Joule heat, and adjusts the working parameters of the cooling module and the induction heater according to the difference between the temperature measurement value of the detection module and the preset value.

[0094] In one embodiment, the protection control module establishes an electromagnetic field model and an eddy current distribution model based on the structure and physical parameters of the eddy current protection system to calculate the total amount of Joule heat on the protection cylinder, the tundish shell, and the air cooling unit of the induction heating module at various working currents and current frequencies;

[0095] The protection control module determines the temperature distribution on the protection tube and the tundish shell when thermally balanced according to the total Joule heat of the protection tube and the tundish shell to determine the arrangement position of the temperature sensor of the detection module.

[0096] Specifically, the protection control module establishes an electromagnetic field model and an eddy current distribution model according to the structure and physical parameters of the eddy current protection system, including:

[0097] A three-dimensional equivalent model of the tundish shell is established based on the structural positional relationship and dimensional data of each part of the tundish shell, and an equivalent induced electromagnetic field model and eddy current distribution model of the tundish are established based on the material conductivity of each part of the tundish shell, the specific arrangement position of the induction heater on the tundish shell, the number of coil turns, the operating current, and the current frequency;

[0098] A three-dimensional equivalent model of the protective tube is established based on the structural position relationship and dimensional data of the protective tube, and an equivalent induced electromagnetic field model and eddy current distribution model of the protective tube are established based on the material conductivity of the protective tube and the specific layout position, number of coil turns, working current and current frequency of the induction heater on the protective tube.

[0099] In practice, a three-dimensional equivalent model of the tundish shell was constructed using Maxwell 3D Design, based on the structural positional relationships of the various components of the tundish shell (particularly the location and width of the eddy current isolation slots on the bottom of the tundish shell). The conductivity of the bottom shell material was set to below 15 MS / m (the conductivity of the eddy current isolation slots was set to 0), simulating the structure and physical properties of the tundish shell in a real environment.

[0100] Based on the specific layout of the induction heater on the tundish shell, the number of coil turns, the operating current, and the current frequency, an equivalent induced electromagnetic field was established on the three-dimensional equivalent model of the tundish shell using Maxwell. This simulated the eddy currents generated by the induction heater in a real environment to form an eddy current distribution model. The Joule heat generated by the eddy current effect was further determined. It can be understood that the thermal balance of the tundish includes eddy current heating of the tundish shell, contact heat transfer between the tundish and the molten steel, and heat exchange between the tundish and the environment.

[0101] Based on the structure and position of the protective tube (including the position and width of the slots on the side of the protective tube that penetrate the surface of the protective tube), a three-dimensional equivalent model of the protective tube was created using Maxwell 3D Design. The conductivity of the protective tube material was set to below 15MS / m (the conductivity of the slots was set to 0) to simulate the structure and physical properties of the protective tube in a real environment.

[0102] According to the number of coil turns, working current and current frequency of the induction heater in the protective tube, Maxwell is used to arrange an equivalent induced electromagnetic field on the three-dimensional equivalent model of the protective tube to simulate the eddy current situation generated by the protective tube under the influence of the induction heater in a real environment to form an eddy current distribution model, and further derive the amount of Joule heat generated by the eddy current effect. It can be understood that the thermal balance of the protective tube includes the eddy current heating of the protective tube, the heat transfer of the induction coil and the heat exchange of the cooling module.

[0103] It is understandable that in an actual production environment, directly measuring the temperature of each part of the tundish shell by shutting down the cooling system of the tundish to obtain the amount of Joule heat generated by each part will cause the tundish shell to overheat, resulting in equipment damage and serious safety problems, and it is difficult to accurately find the layout position of the temperature sensor; the present invention establishes an electromagnetic field model based on the structure and physical parameters of the eddy current protection system, which can accurately determine the specific layout position of the temperature sensor, without the need to test the actual casting equipment, saving costs, easy implementation and high safety.

[0104] Specifically, the temperature sensor is arranged at a maximum temperature position on the tundish shell, a minimum temperature position on the tundish shell, and a maximum temperature position on the protective tube. The maximum temperature position refers to the center position of a predetermined circular area on the surface of the structure corresponding to the maximum Joule heat weight value corresponding to the total Joule heat calculated in the predetermined circular area. The minimum temperature position refers to the center position of a predetermined circular area on the surface of the structure corresponding to the minimum Joule heat weight value corresponding to the total Joule heat calculated in the predetermined circular area. Preferably, the radius of the predetermined circular area is not less than 10 cm. It is understood that the radius of the predetermined circular area is not less than 10 cm to take into account the heat conduction effect and the temperature sensor detection area. Those skilled in the art should understand that the actual arrangement position of the temperature sensor is the exterior of the tundish shell, and the corresponding detection positions of the temperature sensor are set to the aforementioned maximum temperature position on the tundish shell, minimum temperature position on the tundish shell, and maximum temperature position on the protective tube.

[0105] Referring to Figures 8 and 6 , the temperature sensor placement selected for this embodiment is shown. Based on the eddy current distribution model, the figure shows the highest temperature location 22 on the bottom of the tundish shell, the lowest temperature location 23 on the bottom of the tundish shell, and the highest temperature location 13 on the protective tube. These locations are where the eddy current effect is strongest in the tundish shell and protective tube, resulting in the most severe heat generation. Therefore, these locations are selected as the temperature sensor placement locations. It will be appreciated that, due to the symmetrical layout of the tundish shell in this embodiment, the highest temperature locations are also symmetrically distributed, and this will not be further described here.

[0106] The temperature distribution on the tundish shell and the protective cylinder is uneven. Excessive temperature differences at different positions on the tundish shell will reduce the structural stability of the tundish shell. Randomly placed temperature sensors cannot objectively and correctly reflect the working status of the tundish and its induction heater. In order to obtain temperature parameters that can better reflect the working status of the tundish shell and the maximum temperature difference, the present invention selects the position of the temperature extreme value to arrange the temperature sensor, which can accurately determine the critical value of the working equipment in induction heating and improve the monitoring sensitivity of the system working temperature.

[0107] In one embodiment, referring to FIG4 and FIG9 , the cooling module includes an air cooling unit for cooling the heat radiation of the high-temperature molten steel and a liquid cooling unit for cooling the eddy current heat of the induction heater coil and its core;

[0108] Specifically, the air cooling unit is arranged around the outside of the inverted U-shaped upper iron core to cool the inverted U-shaped upper iron core by cold air, wherein the cold air flows from the upper air duct 16 to the lower air duct 17; the liquid cooling unit is arranged inside the cylindrical iron core on which the induction heating coil is wound on the inverted U-shaped upper iron core to cool the induction heating coil by coolant, wherein the cooling liquid path is shown in Figure 4.

[0109] Specifically, the protection control module determines the cooling air volume and coolant flow rate according to the operating current and current frequency of the induction heating module, and determines the adjustment mode of the eddy current protection system according to the actually detected cooling air volume and coolant flow rate;

[0110] The adjustment method includes adjusting the working current, current frequency, cooling air volume, and coolant flow of the induction heating module.

[0111] In one embodiment, the eddy current protection system is set up and adjusted as follows:

[0112] S1: An electromagnetic field model is established based on the structural and physical parameters of the induction heater, molten steel, tundish shell, protective tube, and air ducts (upper and lower ducts). The eddy current distribution and total Joule heat on the protective tube, tundish shell, and upper duct are calculated under different heating currents and frequencies of the induction heater.

[0113] S2: Based on the total Joule heat of the air duct and protective tube, calculate the cooling air volume required to remove the total Joule heat at various ambient temperatures;

[0114] S3: The air cooling module is set to the cooling air volume calculated in step S2, and the temperature distribution and the highest temperature position on the protective tube and the tundish shell at thermal equilibrium are calculated based on the total Joule heat of the protective tube and the air duct;

[0115] S4: The locations of the maximum temperature distribution on the protective tube and tundish shell are calculated according to step S3, and temperature sensors are placed for temperature monitoring. Under the premise that the induction heater uses the corresponding heating current, current frequency, total cooling air volume, and ambient temperature, the actual maximum temperature on the protective tube and tundish shell is measured.

[0116] S5: Compare the calculated and measured values ​​corresponding to the maximum temperature in steps S3 and S4 to verify the accuracy of the calculation model. The temperature distribution results calculated by the model must be close to the actual measured results. Adjust the model's heat dissipation coefficient until the calculation model's accuracy meets the scenario requirements and can be used to calculate temperature distribution under different heating parameters.

[0117] S6: storing the results of the temperature calculation and measurement in the model that meets the accuracy requirements in steps S1-S5, and forming a database of the relationship between the maximum temperature of the protective tube, the upper air duct, and the tundish shell under heating parameters and cooling air volume.

[0118] S7: During the use of the induction heating ladle, the protection control module can firstly reasonably select the cooling air volume according to the heating current and current frequency, so as to avoid energy waste caused by too large an air volume and no cooling effect caused by too small an air volume; secondly, under the premise of reasonable cooling air volume, the actual measured temperature is monitored and compared with the database temperature to avoid excessively high maximum temperature, which may cause sparks and damage to sensors and other equipment.

[0119] It is understandable that the induction heater is placed in the surrounding of high-temperature molten steel. In addition to the heat radiation of the high-temperature molten steel to the heater, there is also eddy current heat generated by the heater coil and the iron core. As mentioned above, the heat radiation of the high-temperature molten steel is mainly cooled by high-speed cooling air, while the eddy current heat of the coil and the iron core is mainly cooled by the coolant. In the present invention, the amount of coolant is designed according to the eddy current heat of the highest iron core and coil of the heater to ensure that the temperature rise of the inlet and outlet water does not exceed 40 degrees. And the eddy current protection system can automatically force the setting of the coolant to start first before the electrical parameters of the induction heater are given. After the electrical parameters of the induction heater are turned off, the coolant can be turned off 15 minutes later to avoid the heater burning out in the state without water cooling protection.

[0120] In implementation, in step S1, Maxwell software is used to calculate the eddy current distribution and the total Joule heat on the protective cylinder, the tundish shell and the air duct under different heating currents and current frequencies.

[0121] In step S2, the calculation formula for the total Joule heat is: Q j =C1·V1·ρ1·T 1Δ ·t

[0122] Among them, Q j is the total amount of Joule heat that needs to be taken away by the cooling working fluid gas; C1 is the specific heat capacity of the cooling working fluid gas; ρ1 is the cooling working fluid gas density; V1 is the cooling working fluid gas flow rate; C 1Δ The temperature rise of the cooling medium gas; t is the equipment operation time;

[0123] The formula for calculating the amount of coolant required to remove the Joule heat of the coil and core is: Q c =C2·V2·S·(T out -T in )·t

[0124] Among them, Q c is the eddy current heat of the coil and core; C2 is the specific heat capacity of the coolant; V2 is the coolant flow rate; S is the cross-sectional area of ​​the coolant channel; T out Out is the coolant outlet temperature; T in In is the coolant inlet temperature.

[0125] Specifically, in this embodiment, the air volume at the inlet and outlet of the air duct is actually monitored. When an abnormal situation occurs, such as: the air duct is blocked, and the outlet air volume is significantly reduced by less than 50% compared with the inlet air volume, the heating current of the induction heater is forced to be reduced or the induction heater is shut down to ensure the safe operation of the sensor, and the monitoring system alarms and reminds the processing.

[0126] Specifically, the protection control module determines the adjustment mode of the working parameters of the induction heater according to the unit temperature rise value of the highest temperature position on the tundish shell actually detected;

[0127] The protection control module is provided with a preset temperature rise value, and the temperature value of the tundish shell is collected by the temperature sensor to monitor the temperature change of the tundish shell (the temperature sensor has been set at least at the highest temperature position and the lowest temperature position of the tundish shell);

[0128] If the detected unit temperature rise value is higher than the preset temperature rise value, the protection control module determines to reduce the heating current of the induction heater or reduce the current frequency of the induction heater.

[0129] In implementation, the unit temperature rise value refers to the temperature rise value per unit time (temperature decrease is a negative value). The preset temperature rise value is determined based on the thermal stress and thermal fatigue tolerance of the tundish shell material, temperature change and volume change rate. Preferably, the preset temperature rise value is between 30°C and 200°C.

[0130] In one embodiment, if the actually detected unit temperature rise value is higher than the preset temperature rise value, it is determined that the working efficiency of the induction heater needs to be reduced, including reducing the heating current of the induction heater or reducing the current frequency of the induction heater. Preferably, the heating current of the induction heater is first reduced, which can effectively reduce the heating power of the induction heater and has energy-saving advantages.

[0131] Specifically, the protection control module determines the adjustment range of the working parameters of the induction heater according to the difference between the temperature at the highest temperature position on the tundish shell and the temperature at the lowest temperature position on the tundish shell that are actually detected;

[0132] The difference is inversely proportional to the adjustment amplitude of the working parameter. It can be understood that the difference is a positive number.

[0133] In one embodiment, the temperature of the highest temperature position on the tundish shell actually detected is set to T 10 The temperature at the lowest temperature position on the tundish shell is T 20 , the difference is ΔT=T 10 -T 20 , the adjustment range of the working parameters of the induction heater includes the current adjustment amount ΔI and the frequency adjustment amount Δf;

[0134] If you choose to adjust the heating current of the induction heater, the current adjustment amount ΔI is determined by the following formula:

[0135] Where, I is the working current value of the induction heater before adjustment, S is the bottom area of ​​the tundish shell, L is the T is the straight-line distance between the highest temperature position on the tundish shell and the lowest temperature position on the tundish shell, ΔT is the difference between the highest temperature position and the lowest temperature position on the tundish shell, T h is the ambient temperature.

[0136] If you choose to adjust the current frequency of the induction heater, the frequency adjustment amount Δf is determined by the following formula:

[0137] Where f is the current frequency value of the induction heater before adjustment, S is the bottom area of ​​the tundish shell, L is the T is the straight-line distance between the highest temperature position on the tundish shell and the lowest temperature position on the tundish shell, ΔT is the difference between the highest temperature position and the lowest temperature position on the tundish shell, T h is the ambient temperature, λ is the frequency conversion coefficient, generally, 1≤λ≤1.3, preferably, λ=1.1.

[0138] Those skilled in the art will appreciate that when reducing the heating current of the induction heater or reducing the current frequency of the induction heater, the current adjustment amount ΔI and the frequency adjustment amount Δf obtained by the above calculations both refer to reduction amounts.

[0139] The present invention determines the adjustment range of the operating parameters of the induction heater based on the difference between the temperature at the highest temperature position on the tundish shell and the temperature at the lowest temperature position on the tundish shell that are actually detected. Since the difference between the temperature at the highest temperature position on the tundish shell and the temperature at the lowest temperature position on the tundish shell can represent the heat exchange capability of the tundish shell itself and its ability to withstand the temperature of molten steel heated by the induction heater, determining the adjustment range of the operating parameters of the induction heater based on the difference can, on the one hand, maximize the normal operation of the tundish, and, on the other hand, reduce the waste of electric energy of the induction heater and improve energy utilization efficiency by accurately calculating the adjustment range of the operating parameters.

[0140] Specifically, the protection control module calculates the eddy current heating temperature rise value of the molten steel according to the unit temperature rise value of the outer bottom surface of the ladle shell in the casting area, and determines the required temperature rise adjustment value of the molten steel according to the eddy current heating temperature rise value of the molten steel.

[0141] In one embodiment, after the molten steel flows out of the steel flow channel, it is still affected by the electromagnetic field of the induction heater and heated by the eddy current effect. Therefore, the temperature of the molten steel heated by the induction heater through the steel flow channel does not need to reach the temperature of the molten steel flowing out of the final casting zone outlet. The unit temperature rise value detected by the temperature sensor arranged on the bottom surface of the tundish shell represents the temperature rise of the molten steel in the casting zone caused by eddy current heating in the casting zone, that is, the temperature rise value of the molten steel eddy current heating, thereby determining the required temperature rise value of the molten steel heated by the induction heater. At this time, the total temperature rise value of the molten steel is composed of the temperature rise value of the molten steel eddy current heating and the temperature rise value of the direct heating of the induction heater, which is expressed by the following formula:

[0142] T v =T w +T f , T v is the total temperature rise, T w is the temperature rise value of molten steel eddy current heating, T f is the direct heating temperature rise value of the induction heater;

[0143] In practice, the unit temperature rise value T of the outer bottom surface of the tundish shell is obtained by the temperature sensor. wk (If there are multiple temperature sensors on the bottom surface, take the average value) Calculate T w , the calculation formula is as follows:

[0144] T w =T wk ×η, η is the conductivity conversion coefficient, which is empirical data and can be calculated in the electromagnetic field model and eddy current distribution model through the actual conductivity of molten steel and the conductivity of the tundish shell, as well as the temperature rise value of the molten steel eddy current heating and the temperature rise value of the bottom surface of the tundish shell.

[0145] Therefore, the required temperature increase adjustment value T q Determined by the following formula: T q =T Q -T w ;

[0146] Where, T Q The required temperature of the molten steel flowing out of the casting area outlet (required temperature rise value), the required temperature rise adjustment value T q is the temperature of the molten steel flowing into the casting zone through the heated steel flow channel of the induction heater, that is, the actual heating target temperature of the molten steel in the steel flow channel, T q Can guide the working parameter setting of the induction heater. Generally, keep T Q Selecting a lower temperature within the required range of the temperature of the molten steel flowing out of the casting zone outlet can improve the heating efficiency of the induction heater and achieve a better energy saving effect.

[0147] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. An eddy current protection system for a channel-type induction heating tundish, characterized in that: include: A channel-type induction heating tundish comprising an injection zone, a casting zone, and a steel flow channel connecting the injection zone and the casting zone, wherein the tundish shell is provided with a quasi-circular through-hole for passage of the induction heater, an eddy current isolating groove extending through the quasi-circular through-hole to the edge of the tundish shell, and an insulating material gasket filled in the eddy current isolating groove, wherein the eddy current isolating groove and the quasi-circular through-hole are both provided between the injection zone and the casting zone; an induction heating module connected to the channel-type induction heating tundish and having an axis of its induction heater coil passing through the quasi-circular through-hole, for heating the molten steel in the steel flow channel through a magnetic field generated by the induction heater coil in an alternating current; An eddy current protection module is connected to the induction heating module and includes a protection tube arranged outside the induction heater coil, and an open groove is opened on the side of the protection tube and penetrates the surface of the protection tube; a cooling module connected to the induction heating module, comprising an air cooling unit for cooling the heat radiation of the high-temperature molten steel and a liquid cooling unit for cooling the eddy current heat of the induction heater coil and its core; a detection module connected to the channel-type induction heating tundish, the induction heating module, and the eddy current protection module, and configured to obtain the temperature of the tundish shell, the temperature of the protection cylinder, the actual operating parameters of the induction heater, and the actual operating parameters of the cooling module; a structural parameter acquisition module for acquiring the ambient temperature of the channel-type induction heating tundish, the specific heat capacity of the coolant of the liquid cooling unit, the cross-sectional area of the coolant channel of the liquid cooling unit, the inner diameter of the steel flow channel, and the electrical parameters of the induction heater; a protection control module, connected to the detection module, the cooling module, and the structural parameter acquisition module, respectively, for determining the eddy current distribution and the total Joule heat on the protective cylinder and the tundish shell according to the structural and physical parameters of the induction heater, the tundish shell, and the protective cylinder, determining the operating parameters of the induction heater and the cooling module according to the total Joule heat, and adjusting the operating parameters of the cooling module and the induction heater according to the difference between the temperature measurement value detected by the detection module and the preset value; The operating parameters of the cooling module include the cooling air volume and the flow rate of the coolant of the air cooling unit, and the operating parameters of the induction heater include the heating current size and current frequency of the induction heater coil.

2. The eddy current protection system according to claim 1, characterized in that: The protection control module establishes an electromagnetic field model and an eddy current distribution model according to the structure and physical parameters of the eddy current protection system to calculate the total amount of Joule heat on the protection cylinder, the tundish shell and the air cooling unit of the induction heating module at various working currents and current frequencies; The protection control module determines the temperature distribution on the protection tube and the tundish shell when thermally balanced according to the total Joule heat of the protection tube and the tundish shell to determine the arrangement position of the temperature sensor of the detection module.

3. The eddy current protection system according to claim 1, characterized in that: The protection control module determines the cooling air volume and coolant flow rate according to the operating current and current frequency of the induction heating module, and determines the adjustment method of the eddy current protection system according to the actually detected cooling air volume and coolant flow rate; The adjustment method includes adjusting the working current, current frequency, cooling air volume, and coolant flow of the induction heating module.

4. The eddy current protection system according to claim 2, characterized in that: The arrangement positions of the temperature sensors include the highest temperature position on the tundish shell, the lowest temperature position on the tundish shell, and the highest temperature position on the protective tube; The highest temperature position is the center position of the preset circular area on the surface of the structure corresponding to the maximum Joule heat weight corresponding to the total Joule heat calculated in the preset circular area, and the lowest temperature position is the center position of the preset circular area on the surface of the structure corresponding to the minimum Joule heat weight corresponding to the total Joule heat calculated in the preset circular area; The radius of the preset circular area is not less than 10 cm.

5. The eddy current protection system according to claim 4, characterized in that: The protection control module determines the adjustment mode of the working parameters of the induction heater according to the unit temperature rise value of the highest temperature position on the tundish shell actually detected; If the unit temperature rise value is higher than the preset temperature rise value, the protection control module determines to reduce the heating current of the induction heater or reduce the current frequency of the induction heater.

6. The eddy current protection system according to claim 5, characterized in that: The protection control module determines the adjustment range of the working parameters of the induction heater according to the difference between the temperature at the highest temperature position on the tundish shell and the temperature at the lowest temperature position on the tundish shell that are actually detected; The difference is inversely proportional to the adjustment amplitude of the operating parameter.

7. The eddy current protection system according to claim 3, characterized in that: The protection control module calculates the molten steel eddy current heating temperature rise value according to the unit temperature rise value of the outer bottom surface of the tundish shell in the casting area, and determines the required temperature rise adjustment value of the molten steel according to the molten steel eddy current heating temperature rise value.

8. The eddy current protection system according to claim 2, characterized in that: The protection control module establishes an electromagnetic field model and an eddy current distribution model according to the structure and physical parameters of the eddy current protection system, including: A three-dimensional equivalent model of the tundish shell is established based on the structural positional relationship and dimensional data of each part of the tundish shell, and an equivalent induced electromagnetic field model and eddy current distribution model of the tundish are established based on the material conductivity of each part of the tundish shell, the specific arrangement position of the induction heater on the tundish shell, the number of coil turns, the operating current, and the current frequency; A three-dimensional equivalent model of the protective tube is established based on the structural position relationship and dimensional data of the protective tube, and an equivalent induced electromagnetic field model and eddy current distribution model of the protective tube are established based on the material conductivity of the protective tube and the specific layout position, number of coil turns, working current and current frequency of the induction heater on the protective tube.

9. The eddy current protection system according to claim 6, characterized in that: The operating parameter adjustment range includes a current adjustment amount ΔI and a frequency adjustment amount Δf; If you choose to adjust the heating current of the induction heater, the current adjustment amount ΔI is determined by the following formula: Where, I is the working current value of the induction heater before adjustment, S is the bottom area of the tundish shell, L is the T is the straight-line distance between the highest temperature position on the tundish shell and the lowest temperature position on the tundish shell, ΔT is the difference between the highest temperature position and the lowest temperature position on the tundish shell, T h is the ambient temperature; If you choose to adjust the current frequency of the induction heater, the frequency adjustment amount Δf is determined by the following formula: Where f is the current frequency value of the induction heater before adjustment, S is the bottom area of the tundish shell, and λ is the frequency conversion coefficient, 1≤λ≤1.

3.

10. The eddy current protection system according to claim 7, characterized in that: The required temperature rise adjustment value is the temperature value of the molten steel flowing into the casting area through the heated flow steel channel of the induction heater. The required temperature rise adjustment value T q Determined by the following formula: T q =T Q -T w ; Where, T Q is the required temperature of the molten steel flowing out of the casting area, T wk is the unit temperature rise value of the outer bottom surface of the tundish shell, T w =T wk ×η, η is the conductivity conversion coefficient.

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