Silicon steel coil annealing furnace and control method thereof

Abstract

The invention belongs to the technical field of silicon steel processing, and discloses a silicon steel coil annealing furnace and a control method thereof, by accurately controlling the heating power of each part and optimizing the flow path of protective gas, the protective gas can be preheated to avoid the formation of local cold spots, and the production efficiency is improved. Heat of the lower end and the outer side of the silicon steel coil can be efficiently transmitted to the upper end and the inner side of the silicon steel coil through airflow, and therefore the temperature deviation between the upper end and the lower end and between the inner side and the outer side of the silicon steel coil is reduced; the problems that a traditional annealing furnace is uneven in temperature distribution and local cold points are formed are effectively solved, and the annealing furnace has the advantages of improving the temperature uniformity of the silicon steel coil, achieving accurate temperature control, improving the annealing effect and improving the quality and performance of the silicon steel coil.

Description

Technical Field

[0001] The present application relates to the technical field of silicon steel processing, and in particular to a silicon steel coil annealing furnace and a control method thereof. Background Art

[0002] Silicon steel coil is an important industrial material, widely used in the fields of electricity, electronics, etc. In order to improve the performance of silicon steel coil, it is usually necessary to anneal it. Generally, a steel coil annealing furnace is used for annealing.

[0003] The traditional steel coil annealing furnace includes a furnace table, a furnace bottom plate, an inner cover and a heating cover. The top of the furnace table and the inner wall of the heating cover are both provided with heaters. When in use, the furnace bottom plate is first placed on the top of the furnace table, and then the silicon steel coil is placed on the furnace bottom plate. Then the inner cover is hoisted to the furnace table to cover the silicon steel coil in the inner cover, and then the heating cover is covered outside the inner cover. Finally, the heaters at the furnace table and the heating cover are started. The heater at the heating cover heats the inner cover by thermal radiation, and the inner cover heats the silicon steel coil by thermal radiation and air convection. The furnace bottom plate transfers the heat energy of the heater at the furnace table to the bottom of the silicon steel coil to heat the silicon steel coil. During the heating process, the protective gas is usually input from the middle of the furnace table, and the protective gas enters the inner cover through the through hole located in the center of the furnace bottom plate.

[0004] However, this traditional steel coil annealing furnace has some significant defects. First, since the heat source is located at the bottom and around the silicon steel coil, the heat source distribution is uneven, resulting in uneven temperature distribution of the silicon steel coil, such as uneven top and bottom temperatures, and uneven inside and outside temperatures. This uneven temperature distribution will directly affect the annealing effect, thereby affecting the final performance of the silicon steel coil. Secondly, the temperature of the protective gas input from the middle of the furnace is relatively low, resulting in cold spots in the silicon steel coil near the protective gas input port, further aggravating the uneven temperature of the silicon steel coil. These problems will not only affect the annealing quality, but may also cause stress inside the silicon steel coil, affecting its subsequent performance.

[0005] In addition, the temperature control system of traditional annealing furnaces is usually relatively simple, generally controlling all heaters uniformly (i.e., the power of all heaters is adjusted synchronously), making it difficult to accurately control the temperature of each part of the silicon steel coil. This makes it difficult for operators to adjust annealing parameters according to silicon steel coils of different specifications and requirements, limiting the flexibility and adaptability of the annealing process. At the same time, due to the lack of effective temperature monitoring and feedback mechanisms, it is difficult to promptly detect and correct temperature anomalies during the annealing process, increasing the risk of product quality fluctuations.

[0006] In view of the above problems, the existing technology needs to be improved. It is necessary to develop an annealing furnace that can improve the temperature uniformity of silicon steel coils and equip it with a corresponding control method to achieve more accurate and flexible temperature control, thereby significantly improving the annealing effect and improving the quality and performance of silicon steel coils. Summary of the invention

[0007] The purpose of the present application is to provide a silicon steel coil annealing furnace and a control method thereof, which can improve the temperature uniformity of the silicon steel coil, achieve precise temperature control, improve the annealing effect, and improve the quality and performance of the silicon steel coil.

[0008] In a first aspect, the present application provides a silicon steel coil annealing furnace, comprising a furnace platform, a furnace bottom plate, an inner cover, a heating cover and a host computer, wherein the furnace bottom plate is placed on the top of the furnace platform and is used to support the silicon steel coil, the inner cover is used to cover the silicon steel coil inside, and the heating cover is used to cover the inner cover inside; the silicon steel coil annealing furnace also includes a temperature sensor group; The top of the furnace is provided with a plurality of first annular heaters which are arranged concentrically and spaced from the inside to the outside, and the heating power of each of the first annular heaters can be adjusted independently; the inner side of the heating cover is provided with a plurality of second annular heaters which are spaced from top to bottom, and the heating power of each of the second annular heaters can be adjusted independently; The furnace table is provided with an air intake structure and an exhaust structure, and the furnace bottom plate is provided with a first through port and a flow guiding structure. The air intake structure, the flow guiding structure, the first through port, the exhaust structure and the inner cover are used to cooperate to guide the protective gas to form an airflow, so that the airflow first flows from the inside to the outside along the furnace bottom plate, then flows upward along the gap between the silicon steel coil and the inner cover, then flows into the inner hole of the silicon steel coil from the upper side of the silicon steel coil, and finally flows out from the lower end of the inner hole of the silicon steel coil; The temperature sensor group is used to detect the temperature of the upper end, lower end, inner side and outer side of the silicon steel coil; The host computer is used to adjust the heating power of each of the first annular heaters and each of the second annular heaters according to the temperature measurement results of the temperature sensor group to reduce the temperature deviation between the upper end and the lower end and between the inner side and the outer side of the silicon steel coil.

[0009] This silicon steel coil annealing furnace can preheat the protective gas to avoid the formation of local cold spots by precisely controlling the heating power of each part and optimizing the flow path of the protective gas, and can use the airflow to more efficiently transfer the heat from the lower end and outer side of the silicon steel coil to the upper end and inner side of the silicon steel coil, thereby reducing the temperature deviation between the upper and lower ends and between the inner and outer sides of the silicon steel coil; it effectively solves the problems of uneven temperature distribution and the formation of local cold spots in traditional annealing furnaces, and has the advantages of improving the temperature uniformity of silicon steel coils, achieving precise temperature control, improving annealing effects, and improving the quality and performance of silicon steel coils.

[0010] Preferably, the air intake structure is used to guide the protective gas provided by the external air supply system to the top middle of the furnace table; The guide structure is used to guide the protective gas flowing out from the middle of the top of the furnace platform to flow along the furnace bottom plate to the edge of the furnace bottom plate and then flow out to the gap between the silicon steel coil and the inner cover; The first through port is arranged at the center of the furnace bottom plate, the exhaust structure comprises an exhaust passage connected to the top center of the furnace platform, and the first through port is used to connect the inner hole of the silicon steel coil and the exhaust passage.

[0011] This gas flow path design solves the problem caused by the shielding gas directly entering the inner hole of the silicon steel coil from the center of the furnace bottom plate in the traditional annealing furnace. The new flow path allows the shielding gas to fully contact the furnace bottom plate and the outer surface of the silicon steel coil first, which is conducive to preheating the shielding gas and uniformly heating the silicon steel coil. At the same time, the flow of shielding gas from the outside to the inside of the silicon steel coil helps to reduce the temperature difference between the inside and outside of the silicon steel coil and improve temperature uniformity. In addition, the gas maintains full contact with the silicon steel coil during the entire flow process, which can better protect the surface of the silicon steel coil and prevent oxidation.

[0012] Preferably, the air intake structure includes a first annular air groove opened in the middle of the top of the furnace table and an air intake channel connected to the first annular air groove, and the air intake channel is used to connect with an external air supply system to input the protective gas provided by the external air supply system into the first annular air groove.

[0013] The air intake structure can improve the uniformity of the shielding gas input, thereby improving the temperature uniformity of the silicon steel coil.

[0014] Preferably, the guide structure includes a second annular air groove and at least one guide channel, the second annular air groove is opened in the middle of the bottom of the furnace bottom plate opposite to the first annular air groove, the guide channel is arranged at the bottom or inside of the furnace bottom plate, one end of the guide channel is connected to the second annular air groove, and the other end extends to the edge of the furnace bottom plate and is connected to the top edge of the furnace bottom plate.

[0015] Preferably, a downwardly protruding positioning ring is provided at the bottom edge of the furnace bottom plate, the inner diameter of the positioning ring is the same as the outer diameter of the top of the furnace platform, and the positioning ring is used to be inserted into the top of the furnace platform to position the furnace bottom plate.

[0016] Preferably, the inner cover comprises a cylinder wall and a cover body arranged at the upper end of the cylinder wall, and the upper and lower positions of the cover body are adjustable.

[0017] Preferably, a heat-conducting pressure plate is provided in the cover body, and the heat-conducting pressure plate is used to abut against the upper end of the silicon steel coil to transfer the heat of the inner cover to the upper end of the silicon steel coil.

[0018] Preferably, the heat-conducting pressure plate and the top wall of the cover body form an air cavity, a second through port is provided in the middle of the heat-conducting pressure plate, and a plurality of air vents are provided at the edge of the heat-conducting pressure plate, the second through port is used to connect the air cavity and the inner hole of the silicon steel coil, and the air vents are used to connect the air cavity and the gap between the cylinder wall and the silicon steel coil.

[0019] In a second aspect, the present application provides a control method, which is applied to the host computer in the silicon steel coil annealing furnace described above, comprising the steps of: A1. Obtain the temperatures of the upper end, lower end, inner side and outer side of the silicon steel coil measured by the temperature sensor group; A2. Calculate the temperature difference between the upper and lower ends of the silicon steel coil, recorded as the axial temperature difference; and calculate the temperature difference between the inner and outer temperatures of the silicon steel coil, recorded as the radial temperature difference; A3. Adjust the heating power of each first annular heater and each second annular heater according to the axial temperature difference and the radial temperature difference to reduce the temperature deviation between the upper end and the lower end and between the inner side and the outer side of the silicon steel coil.

[0020] Preferably, step A3 comprises: A301. Obtain the reference baseline line power of the first annular heater according to the axial temperature difference; the line power is the heating power of the first annular heater per unit length, and the reference baseline line power is the reference baseline value of the line power; A302. Obtaining a reference power of the second annular heater according to the radial temperature difference; A303. Based on the reference baseline power, adjusting the line power of each of the first annular heaters according to the radial temperature difference, and calculating the target power of each of the first annular heaters according to the adjusted line power; A304. Based on the reference power, the power of each of the second annular heaters is adjusted according to the axial temperature difference to obtain a target power of each of the second annular heaters; A305. Adjust the heating power of each of the first annular heaters and each of the second annular heaters to the corresponding target power.

[0021] Beneficial effects: The silicon steel coil annealing furnace and control method provided in the present application can preheat the protective gas to avoid the formation of local cold spots by accurately controlling the heating power of each part and optimizing the flow path of the protective gas, and can use the airflow to more efficiently transfer the heat from the lower end and outer side of the silicon steel coil to the upper end and inner side of the silicon steel coil, thereby reducing the temperature deviation between the upper and lower ends and between the inner and outer sides of the silicon steel coil; it effectively solves the problems of uneven temperature distribution and the formation of local cold spots in traditional annealing furnaces, and has the advantages of improving the temperature uniformity of silicon steel coils, achieving precise temperature control, improving annealing effects, and improving the quality and performance of silicon steel coils. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of a silicon steel coil annealing furnace provided in an embodiment of the present application.

[0023] Figure 2 This is a top view of the stove.

[0024] Figure 3 It is a three-dimensional diagram of a furnace bottom plate, in which the bottom of the furnace bottom plate is placed upward.

[0025] Figure 4 It is a three-dimensional diagram of the furnace bottom plate, in which the top of the furnace bottom plate is placed upward.

[0026] Figure 5 It is a schematic diagram of the structure of the inner cover.

[0027] Figure 6 A flow chart of a control method provided in an embodiment of the present application.

[0028] Figure 7 This is the line power regulation schematic diagram of the first ring heater.

[0029] Figure 8 This is the power regulation schematic diagram of the second ring heater.

[0030] Explanation of reference numerals: 1. furnace table; 101. air intake structure; 102. exhaust structure; 103. exhaust channel; 104. first annular air groove; 105. air intake channel; 106. first mounting groove; 2. furnace bottom plate; 201. first through port; 202. flow guide structure; 203. second annular air groove; 204. flow guide channel; 205. third annular air groove; 206. air outlet; 207. positioning ring; 208. first positioning groove; 3. inner cover; 301. cylinder wall; 302. cover; 303. heat-conducting pressure plate; 304. air cavity; 305. second through port; 306. air vent; 307. second positioning groove; 4. heating cover; 5. upper computer; 6. temperature sensor group; 7. first annular heater; 8. second annular heater; 90. silicon steel coil. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0032] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0033] During the annealing process of silicon steel coils, temperature uniformity is critical to product quality. Traditional steel coil annealing furnaces have uneven heat source distribution, which leads to uneven temperature during the annealing process of silicon steel coils. Specifically, since the heaters are mainly located at the bottom and around the silicon steel coils, there are obvious differences in the upper and lower temperatures and the internal and external temperatures of the silicon steel coils. In addition, the low-temperature protective gas input from the middle of the furnace will form a cold spot near the input port, further exacerbating the temperature unevenness. This problem of uneven temperature distribution directly affects the annealing effect, thereby reducing the overall quality and performance of the silicon steel coils.

[0034] Therefore, solving the problems of uneven temperature and formation of local cold spots during the annealing process of silicon steel coils is of great significance for improving the quality and performance of silicon steel coils.

[0035] To do this, please refer to Figure 1-Figure 5 In some embodiments of the present application, a silicon steel coil annealing furnace comprises a furnace platform 1, a furnace bottom plate 2, an inner cover 3, a heating cover 4 and a host computer 5, wherein the furnace bottom plate 2 is placed on the top of the furnace platform 1 and is used to support the silicon steel coil 90, the inner cover 3 is used to cover the silicon steel coil 90 inside, and the heating cover 4 is used to cover the inner cover 3 inside; the silicon steel coil annealing furnace also comprises a temperature sensor group 6; The top of the furnace 1 is provided with a plurality of first annular heaters 7 which are arranged concentrically and spaced from the inside to the outside, and the heating power of each first annular heater 7 can be adjusted independently; the inner side of the heating cover 4 is provided with a plurality of second annular heaters 8 which are spaced from top to bottom, and the heating power of each second annular heater 8 can be adjusted independently; The furnace table 1 is provided with an air intake structure 101 and an exhaust structure 102, and the furnace bottom plate 2 is provided with a first through port 201 and a guide structure 202. The air intake structure 101, the guide structure 202, the first through port 201, the exhaust structure 102 and the inner cover 3 are used to cooperate and guide the protective gas to form an airflow, so that the airflow first flows from the inside to the outside along the furnace bottom plate 2, then flows upward along the gap between the silicon steel coil 90 and the inner cover 3, then flows into the inner hole of the silicon steel coil 90 from the upper side of the silicon steel coil 90, and finally flows out from the lower end of the inner hole of the silicon steel coil 90 (the airflow direction refers to Figure 1 direction indicated by the arrow in the figure); The temperature sensor group 6 is used to detect the temperature of the upper end, lower end, inner side and outer side of the silicon steel coil 90; The host computer 5 is used to adjust the heating power of each first annular heater 7 and each second annular heater 8 according to the temperature measurement result of the temperature sensor group 6 to reduce the temperature deviation between the upper end and the lower end and between the inner side and the outer side of the silicon steel coil 90 (the temperature deviation refers to the absolute value of the temperature difference).

[0036] This silicon steel coil annealing furnace can preheat the protective gas to avoid the formation of local cold spots by precisely controlling the heating power of each part and optimizing the protective gas flow path, and can use the airflow to more efficiently transfer the heat from the lower end and outer side of the silicon steel coil 90 to the upper end and inner side of the silicon steel coil 90, thereby reducing the temperature deviation between the upper and lower ends and between the inner and outer sides of the silicon steel coil 90; it effectively solves the problems of uneven temperature distribution and the formation of local cold spots in traditional annealing furnaces, and has the advantages of improving the temperature uniformity of the silicon steel coil 90, achieving precise temperature control, improving the annealing effect, and improving the quality and performance of the silicon steel coil 90.

[0037] The first annular heater 7 refers to a heating device which is concentrically arranged and spaced apart from the inside to the outside on the top of the furnace table 1, and can be implemented by a resistance wire heater or an infrared heater.

[0038] The second annular heaters 8 refer to heating devices arranged from top to bottom at intervals inside the heating cover 4, and can be implemented by resistance wire heaters or infrared heaters. The second annular heaters 8 have the same structural dimensions and heating performance.

[0039] The temperature sensor group 6 refers to a set of sensors for detecting the temperatures of different positions of the silicon steel coil 90 , which may be implemented by thermocouples or infrared thermometers.

[0040] The core innovation of this application is the use of multiple independently adjustable power annular heaters combined with an optimized airflow path design. By arranging multiple annular heaters on the top of the furnace 1 and the inner side of the heating hood 4, the temperature of each part of the silicon steel coil 90 is accurately controlled. At the same time, by designing a specific airflow path, the problem of cold spots forming near the protective gas inlet is solved. This design can not only significantly improve the temperature uniformity of the silicon steel coil 90, but also avoid the formation of local cold spots, thereby greatly improving the annealing effect and product quality.

[0041] Specifically, the airflow first flows along the furnace bottom plate 2 to absorb the heat of the furnace bottom plate 2 to reduce the temperature deviation between the upper and lower ends of the silicon steel coil 90 and preheat the airflow to avoid the formation of local cold spots. The airflow flows upward on the outside of the silicon steel coil 90 to absorb the heat of the outside of the silicon steel coil 90 to reduce the temperature deviation between the inside and outside of the silicon steel coil 90 and further increase the airflow temperature. When the airflow flows through the upper and inner sides of the silicon steel coil 90, the high-temperature airflow can increase the heating efficiency of the upper and inner sides of the silicon steel coil 90, thereby further reducing the temperature deviation between the upper and lower ends and between the inside and outside of the silicon steel coil 90; therefore, the temperature uniformity of the silicon steel coil 90 is effectively improved and the formation of local cold spots is avoided.

[0042] Among them, lifting ears can be provided on the inner cover 3 and the heating cover 4 to facilitate the lifting of the inner cover 3 and the heating cover 4.

[0043] Specifically, see Figure 1 , the air intake structure 101 is used to guide the protective gas provided by the external air supply system to the top middle part of the furnace table 1; The flow guide structure 202 is used to guide the protective gas flowing out from the middle of the top of the furnace platform 1 to flow along the furnace bottom plate 2 to the edge of the furnace bottom plate 2 and flow out to the gap between the silicon steel coil 90 and the inner cover 3; The first through opening 201 is disposed at the center of the furnace bottom plate 2 . The exhaust structure 102 includes an exhaust passage 103 connected to the top center of the furnace platform 1 . The first through opening 201 is used to connect the inner hole of the silicon steel coil 90 and the exhaust passage 103 .

[0044] This gas flow path design solves the problem caused by the shielding gas directly entering the inner hole of the silicon steel coil 90 from the center of the furnace bottom plate 2 in the traditional annealing furnace. The new flow path allows the shielding gas to fully contact the furnace bottom plate 2 and the outer surface of the silicon steel coil 90 first, which is conducive to preheating the shielding gas and uniformly heating the silicon steel coil 90. At the same time, the flow of the shielding gas from the outside to the inside of the silicon steel coil 90 helps to reduce the temperature difference between the inside and outside of the silicon steel coil 90 and improve the temperature uniformity. In addition, the shielding gas maintains full contact with the silicon steel coil 90 during the entire flow process, which can better protect the surface of the silicon steel coil 90 and prevent oxidation.

[0045] The size of the first through hole 201 can also be adjusted according to specific needs. Generally, the diameter of the first through hole 201 can be designed to be slightly smaller than the inner diameter of the silicon steel coil 90 to ensure that the protective gas can fully contact the inner surface of the silicon steel coil 90.

[0046] The exhaust channel 103 in the exhaust structure 102 can be designed as a separate pipe or a channel opened in the furnace 1, and its diameter can be adjusted according to the required exhaust volume. By adjusting the size and shape of the exhaust channel 103, the flow rate of the protective gas in the silicon steel coil 90 can be controlled, thereby optimizing the heat exchange effect. In fact, a flow regulating valve can also be set at the exhaust channel 103 to adjust the flow rate of the protective gas in the silicon steel coil 90.

[0047] In some embodiments, see Figure 1 , Figure 2 The air intake structure 101 includes a first annular air groove 104 opened in the middle of the top of the furnace table 1 and an air intake channel 105 connected to the first annular air groove 104. The air intake channel 105 is used to connect with an external air supply system to input the protective gas provided by the external air supply system into the first annular air groove 104.

[0048] By adopting this air intake structure 101, the protective gas can be evenly distributed in the first annular gas groove 104 before entering the inner cover 3, avoiding the problem of local cold spots that may be caused by direct input from a single point. The annular design ensures the uniform distribution of the protective gas on the top of the entire furnace 1, which not only improves the uniformity of the distribution of the protective gas, but also helps to improve the overall heating uniformity of the silicon steel coil 90. Specifically, when the protective gas is input into the first annular gas groove 104 through the air intake channel 105, the protective gas will quickly diffuse and evenly distribute in the first annular gas groove 104. Due to the design of the first annular gas groove 104, the pressure of the protective gas remains basically consistent throughout the first annular gas groove 104, which ensures that the flow rate of the gas released from the first annular gas groove 104 to the top of the furnace 1 is basically equal in all directions. This uniform gas distribution is crucial to maintaining the stability of the temperature field in the furnace, and can effectively reduce the formation of local hot and cold spots.

[0049] The first annular gas groove 104 can be designed to be circular, elliptical or polygonal in shape to adapt to different furnace 1 structures, wherein a circular shape is preferred. The air inlet channel 105 can be a single independent pipeline or an independent channel opened in the furnace 1, or can be a plurality of independent branch pipelines or a plurality of branch channels opened in the furnace 1 to ensure that the protective gas can be uniformly input into the first annular gas groove 104. The connection position of the air inlet channel 105 and the first annular gas groove 104 can be set at the bottom or side of the first annular gas groove 104, and the specific position can be determined according to actual needs and installation convenience.

[0050] In some embodiments, see Figure 1 , Figure 3 and Figure 4 The guide structure 202 includes a second annular air groove 203 and at least one guide channel 204. The second annular air groove 203 is opened in the middle of the bottom of the furnace bottom plate 2, facing the first annular air groove 104. The guide channel 204 is set at the bottom or inside of the furnace bottom plate 2. One end of the guide channel 204 is connected to the second annular air groove 203, and the other end extends to the edge of the furnace bottom plate 2 and is connected to the top edge of the furnace bottom plate 2.

[0051] This design achieves uniform distribution of the protective gas through the ingenious cooperation of the second annular gas groove 203 and the guide channel 204, thereby improving the temperature uniformity and annealing effect of the silicon steel coil 90 during the annealing process. Specifically, the second annular gas groove 203 is opened in the middle of the bottom of the furnace bottom plate 2, facing the position of the first annular gas groove 104. This design ensures that the protective gas can enter the second annular gas groove 203 evenly from the first annular gas groove 104. The shape of the second annular gas groove 203 can be circular, elliptical or polygonal, preferably circular.

[0052] Among them, it is preferred that a plurality of guide channels 204 are provided (4 to 12 can be provided, but not limited thereto), and these guide channels 204 are evenly arranged around the first through port 201 to improve the uniformity of distribution of the shielding gas. The cross section of each guide channel 204 can be circular, square or other shapes, and its diameter or width can be set according to actual needs. Each guide channel 204 can be a straight channel, an arc channel, a spiral channel or other curved channel (the curved channel can increase the flow path of the shielding gas, thereby improving the preheating effect).

[0053] In actual application, the protective gas first enters the second annular gas groove 203 from the first annular gas groove 104. Due to the design of the second annular gas groove 203, the protective gas can be initially evenly distributed before entering the guide channel 204. Then, the protective gas flows evenly to the edge of the furnace bottom plate 2 through multiple guide channels 204. In this process, the protective gas fully contacts the furnace bottom plate 2, absorbs heat and distributes it evenly. Finally, the protective gas flows out from the top edge of the furnace bottom plate 2, forming a uniform airflow that wraps the entire silicon steel coil 90.

[0054] In some embodiments, see Figure 3 , Figure 4 The guide structure 202 also includes a third annular air groove 205 arranged on the bottom edge of the furnace bottom plate 2 and a plurality of air outlet holes 206 evenly distributed on the edge of the furnace bottom plate 2. One end of the air outlet hole 206 is connected to the top of the furnace bottom plate 2, and the other end is connected to the third annular air groove 205.

[0055] The protective gas first flows into the third annular gas groove 205 from each guide channel 204, and forms a uniformly distributed pressure in the third annular gas groove 205, and then flows out evenly from each outlet hole 206 to the top edge of the furnace bottom plate 2, further improving the uniformity of airflow distribution, thereby improving heating uniformity.

[0056] The two ends of the air outlet 206 may be designed to be trumpet-shaped to reduce airflow resistance and disperse the airflow, so that the protective gas can flow out from the top edge of the furnace bottom plate 2 more easily.

[0057] In some possible implementations, see Figure 3 A downwardly protruding positioning ring 207 is provided at the bottom edge of the furnace bottom plate 2 , and the inner diameter of the positioning ring 207 is the same as the outer diameter of the top of the furnace platform 1 . The positioning ring 207 is used to be inserted into the top of the furnace platform 1 to position the furnace bottom plate 2 .

[0058] In this way, the furnace bottom plate 2 can be accurately positioned on the furnace table 1 so that the first annular air groove 104 and the second annular air groove 203 are aligned.

[0059] The positioning ring 207 can be a continuous annular structure or a discontinuous structure composed of multiple segments. The height of the positioning ring 207 can be designed according to actual needs, and can usually be set to 10 mm-50 mm. The positioning ring 207 can be fixed to the furnace bottom plate 2 by welding, bolt connection or integral molding.

[0060] Furthermore, the inner side surface of the positioning ring 207 and the top edge of the furnace table 1 can be provided with mutually matching guiding inclined surfaces to reduce the difficulty of inserting the positioning ring 207 into the top of the furnace table 1 .

[0061] The positioning structure of the present application not only solves the problem of inaccurate positioning between the furnace bottom plate 2 and the furnace table 1, but also brings a series of technical effects. First, it ensures the precise alignment of the first annular gas groove 104 and the second annular gas groove 203, improves the uniformity of the distribution of the protective gas, and thus improves the annealing quality of the silicon steel coil 90. Secondly, the stable position of the furnace bottom plate helps to maintain the uniformity of heating of the silicon steel coil 90, reducing the risk of local overheating or underheating. Finally, the simplified installation process improves production efficiency and reduces the possibility of human operation errors.

[0062] Furthermore, at least one first positioning groove 208 may be provided on the top of the furnace bottom plate 2 , and the first positioning groove 208 is used to install a temperature sensor for detecting the temperature of the lower end of the silicon steel coil 90 to prevent the temperature sensor from being crushed by the silicon steel coil 90 .

[0063] In some preferred embodiments, see Figure 1 and Figure 2The top of the furnace 1 is provided with a plurality of first mounting grooves 106, which correspond to the first annular heaters 7 one by one, and each first annular heater 7 is respectively arranged in the corresponding first mounting groove 106, so that the first annular heater 7 does not protrude from the top of the furnace 1. Thus, the furnace bottom plate 2 is stably supported on the top of the furnace 1, and the furnace bottom plate 2 is prevented from being deformed due to excessive force locally.

[0064] Preferably, see Figure 1 , Figure 5 The inner cover 3 includes a cylinder wall 301 and a cover 302 arranged at the upper end of the cylinder wall 301, and the upper and lower positions of the cover 302 are adjustable.

[0065] This design allows the height of the cover 302 to be adjusted according to the different sizes of silicon steel coils 90, so as to better adapt to the silicon steel coils 90 of different heights, and improve the applicability and flexibility of the annealing furnace. When the cover 302 is adjusted to a suitable height, the cover 302 can be as close to the upper end of the silicon steel coil 90 as possible, which can not only improve the heating efficiency of the upper side of the silicon steel coil 90, but also optimize the flow path of the protective gas. The protective gas can be more evenly distributed around the silicon steel coil 90, reducing heat loss and further improving heating uniformity.

[0066] The adjustability of the cover 302 can be achieved in a variety of ways. For example, a plurality of vertically arranged slots can be provided on the inner side of the cylinder wall 301, and a protrusion that matches the slot can be provided on the edge of the cover 302, and the position of the cover 302 can be adjusted by inserting the protrusion into the slots of different heights. Another way is to provide a retractable support structure between the cylinder wall 301 and the cover 302, such as a hydraulic cylinder or a cylinder, and adjust the height of the cover by controlling the extension and contraction of the support structure. A threaded adjustment mechanism can also be used, in which a threaded hole is provided on the cylinder wall 301, and a screw that matches the hole is provided on the edge of the cover 302, and the height of the cover 302 is adjusted by rotating the screw; or, an internal thread is provided on one of the upper end of the cylinder wall 301 and the lower end of the cover 302, and an external thread is provided on the other, and the internal thread and the external thread are meshed, and the upper and lower position adjustment of the cover 302 can be achieved by rotating the cover 302.

[0067] In addition, in order to further improve the heating efficiency and uniformity, a reflective coating can be provided inside the cover 302 to enhance the heat radiation effect. At the same time, a sealing ring is provided at the connection between the cover 302 and the cylinder wall 301 to prevent heat loss and protection gas leakage.

[0068] Further, see Figure 1 , Figure 5 A heat-conducting pressure plate 303 may be provided in the cover body 302 , and the heat-conducting pressure plate 303 is used to abut against the upper end of the silicon steel coil 90 to transfer the heat of the inner cover 3 to the upper end of the silicon steel coil 90 .

[0069] This design solves the problem of insufficient heating of the upper end of the silicon steel coil 90 in the conventional annealing furnace, and improves the uniformity of heating of the entire silicon steel coil 90. The heat-conducting pressure plate 303, as a heat transfer medium, significantly improves the heating effect of the upper end of the silicon steel coil 90, and helps to achieve a more uniform and high-quality annealing process.

[0070] The heat-conducting pressure plate 303 can be made of a variety of materials, such as high thermal conductivity metal materials such as copper, aluminum or their alloys, or specially treated ceramic materials. The shape of the heat-conducting pressure plate 303 can be flat, arc-shaped or other shapes that can fit the upper end of the silicon steel coil 90.

[0071] Further, see Figure 1 , Figure 5 The heat-conducting pressure plate 303 and the top wall of the cover body 302 form an air cavity 304, a second through port 305 is provided in the middle of the heat-conducting pressure plate 303, and a plurality of air vents 306 are provided at the edge of the heat-conducting pressure plate 303. The second through port 305 is used to connect the air cavity 304 and the inner hole of the silicon steel coil 90, and the air vents 306 are used to connect the air cavity 304 and the gap between the cylinder wall 301 and the silicon steel coil 90.

[0072] The second through opening 305 allows gas to enter the inner hole of the silicon steel coil 90, while the multiple vent holes 306 on the edge ensure that the gas can evenly flow into the air cavity 304. This air flow distribution method can effectively improve the temperature uniformity of the silicon steel coil 90 during the annealing process, thereby improving the annealing quality.

[0073] The vent holes 306 may be evenly distributed on the edge of the heat-conducting pressure plate 303 , and the number of the vent holes 306 may be determined according to the diameter of the silicon steel coil 90 and the required air flow rate.

[0074] Furthermore, feathers may be provided on the upper surface of the heat conductive pressure plate 303 to improve the heat exchange efficiency between the heat conductive pressure plate 303 and the airflow, thereby improving the heating efficiency of the top of the silicon steel coil 90 and further reducing the temperature deviation between the upper and lower ends of the silicon steel coil 90 .

[0075] In addition, a second positioning groove 307 may be provided on the lower surface of the heat-conducting pressure plate 303 , and the second positioning groove 307 is used to install a temperature sensor for detecting the temperature of the upper end of the silicon steel coil 90 to prevent the heat-conducting pressure plate 303 from crushing the temperature sensor.

[0076] It should be noted that the temperature sensor group 6 includes at least one temperature sensor for detecting the temperature of the upper end of the silicon steel coil 90, at least one temperature sensor for detecting the temperature of the lower end of the silicon steel coil 90, at least one temperature sensor for detecting the temperature of the inner side of the silicon steel coil 90 (mounted on the inner side of the silicon steel coil 90), and at least one temperature sensor for detecting the temperature of the outer side of the silicon steel coil 90 (mounted on the outer side of the silicon steel coil 90). When there are multiple temperature sensors for detecting the temperature of the upper end of the silicon steel coil 90, multiple second positioning grooves 307 are correspondingly provided, and when there are multiple temperature sensors for detecting the temperature of the lower end of the silicon steel coil 90, multiple first positioning grooves 208 are correspondingly provided.

[0077] refer to Figure 6 The present application provides a control method, which is applied to the upper computer 5 in the silicon steel coil annealing furnace mentioned above, and comprises the steps of: A1. Obtain the temperature of the upper end, lower end, inner side and outer side of the silicon steel coil 90 measured by the temperature sensor group 6; A2. Calculate the temperature difference between the upper and lower ends of the silicon steel coil 90, recorded as the axial temperature difference; and calculate the temperature difference between the inner and outer temperatures of the silicon steel coil 90, recorded as the radial temperature difference; A3. Adjust the heating power of each first annular heater 7 and each second annular heater 8 according to the axial temperature difference and the radial temperature difference to reduce the temperature deviation between the upper end and the lower end and between the inner side and the outer side of the silicon steel coil 90.

[0078] Compared with the traditional fixed heating method, this dynamic adjustment method can better adapt to silicon steel coils 90 of different specifications and states, and improve the flexibility and adaptability of the annealing process. By reducing the temperature deviation, the annealing quality of the silicon steel coil 90 can be effectively improved, and its magnetic and mechanical properties can be improved, thereby improving product quality.

[0079] When a plurality of temperature sensors are disposed on a certain side of the silicon steel coil 90 , the average value of the temperature measurement results of all the temperature sensors on the same side may be calculated as the temperature of the corresponding side.

[0080] Among them, assuming that the upper end temperature is T1, the lower end temperature is T2, and the axial temperature difference is Tz, then Tz=T1-T2; assuming that the inner temperature is T3, the outer temperature is T4, and the radial temperature difference is Tr, then Tr=T3-T4.

[0081] In some embodiments, step A3 comprises: A301. Obtain the reference baseline power of the first annular heater 7 according to the axial temperature difference; the line power is the heating power of the first annular heater 7 per unit length, and the reference baseline power is the reference reference value of the line power; A302. Obtain the reference power of the second annular heater 8 according to the radial temperature difference; A303. Based on the reference baseline power, the line power of each first annular heater 7 is adjusted according to the radial temperature difference, and the target power of each first annular heater 7 is calculated according to the adjusted line power; A304. Based on the reference power, the power of each second annular heater 8 is adjusted according to the axial temperature difference to obtain the target power of each second annular heater 8; A305. Adjust the heating power of each first annular heater 7 and each second annular heater 8 to the corresponding target power.

[0082] By precisely adjusting the power of heaters at different positions, the problem of uneven temperature during the annealing of silicon steel coils is effectively solved. This method considers the axial and radial temperature differences respectively, introduces the concepts of reference power and line power, and adopts a step-by-step adjustment method to achieve precise control of the temperature of the silicon steel coil 90 degrees above and below and inside and outside.

[0083] Among them, in step A301, a preset corresponding relationship or algorithm is used to determine the reference baseline power. For example, the reference baseline power corresponding to different axial temperature differences can be preset (the optimal baseline power can be determined through experiments as the reference baseline power), forming a reference baseline power query table, and in actual applications, the corresponding reference baseline power can be obtained by querying the reference baseline power query table according to the actual axial temperature difference; or, the optimal baseline power under different axial temperature differences can be determined through experiments, and then a reference baseline power calculation formula can be generated by fitting, and in actual applications, the actual axial temperature difference can be substituted into the reference baseline power calculation formula to calculate the corresponding reference baseline power.

[0084] Among them, in step A302, a preset corresponding relationship or algorithm is used to determine the reference benchmark power. For example, the reference benchmark powers corresponding to different radial temperature differences can be preset (the optimal benchmark power can be determined through experiments as the reference benchmark power) to form a reference benchmark power query table. In actual applications, the corresponding reference benchmark power can be obtained by querying the reference benchmark power query table according to the actual radial temperature difference; or, the optimal benchmark power under different axial temperature differences can be determined through experiments, and then a reference benchmark power calculation formula can be generated by fitting. In actual applications, the actual radial temperature difference is substituted into the reference benchmark power calculation formula to calculate the corresponding reference benchmark power.

[0085] Wherein, step A303 includes: B1. Calculate the temperature change rate of the silicon steel coil 90 from the inside to the outside in the radial direction according to the radial temperature difference and the radial thickness of the silicon steel coil 90 (ie, the difference between the outer diameter and the inner diameter), which is recorded as the radial temperature change rate; B2. The rate of change of the line power from the inside to the outside along the top of the furnace 1 is calculated according to the radial temperature change rate, which is recorded as the radial line power change rate; the positive and negative of the radial line power change rate is opposite to the positive and negative of the radial temperature change rate; B3. Calculate the adjusted line power of each first annular heater 7 according to the radial line power change rate, the radial position of each first annular heater 7 (the distance from the center circle line of the first annular heater 7 to the central axis of the furnace 1, which is equal to the radius of the center circle line of the first annular heater 7) and the reference baseline line power; from inside to outside, the adjusted line power of each first annular heater 7 changes according to the radial line power change rate; B4. Calculate the target power of each first ring-shaped heater 7 according to the adjusted line power of each first ring-shaped heater 7 and the length of each first ring-shaped heater 7 .

[0086] Specifically, in step B1, assuming that the radial thickness is R and the radial temperature change rate is Vr, then Vr=Tr / R.

[0087] Furthermore, in step B2, assuming that the radial line power change rate is Wr, Wr can be calculated using the following formula: Wr=-k*Vr, where k is a positive proportional parameter.

[0088] Further, refer to Figure 7 , P0 in the figure is the reference baseline line power, straight line L1 is a straight line with a slope equal to the radial line power change rate Wr, L2 is a straight line with a constant line power of P0, and the radial position corresponding to the intersection of L1 and L2 is the midpoint of the radial position of the first annular heater 7 (equal to the average of the radial position r1 of the innermost first annular heater 7 and the radial position rn of the outermost first annular heater 7, and n is the total number of first annular heaters 7), r1 to rn are the radial positions of each first annular heater 7, and P1 to Pn are the line power values ​​of the points corresponding to r1 to rn on the straight line L1 (P1 to Pn can be calculated based on the straight line L1 and r1 to rn), as the adjusted line power of each first annular heater 7.

[0089] Thus, in step B3, a straight line L1 is determined according to P0, r1 and rn, wherein the slope of the straight line L1 is Wr, and it passes through the point ((r1+rn) / 2, P0), and then the ordinate values ​​(which are line power) of the points whose abscissas are r1 to rn on the straight line L1 are calculated as the adjusted line power of each first annular heater 7. By adopting this method to adjust the line power, the heating line power of the lower end of the silicon steel coil 90 along the radial direction can be gradually changed while ensuring that the deviation between the total heating power of the lower end of the silicon steel coil 90 and the reference total heating power when all the first annular heaters 7 work at P0 is small, so as to effectively reduce the temperature deviation between the inner and outer sides; for example, when the radial temperature difference is negative (the inner temperature is generally lower than the outer temperature, so the radial temperature difference is usually negative), the line power of each first annular heater 7 gradually decreases from the inner to the outer side in the radial direction, so that the heating speed of the inner side is increased and the heating speed of the outer side is reduced, thereby reducing the temperature deviation between the inner and outer sides on the basis of ensuring the stability of the total heating power of the lower end.

[0090] Furthermore, in step B4, the target power of each first annular heater 7 is calculated according to the following formula: Wi_r=Pi*li, i=1, 2, …, n; wherein Wi_r is the target power of the i-th first annular heater 7, Pi is the adjusted line power of the i-th first annular heater 7, and li is the length of the i-th first annular heater 7 (equal to the circumference of its central circular ring line).

[0091] Wherein, step A304 includes: C1. Calculate the temperature change rate of the silicon steel coil 90 from top to bottom based on the axial temperature difference and the height of the silicon steel coil 90, and record it as the axial temperature change rate; C2. The power change rate of the second annular heater 8 from top to bottom is calculated according to the axial temperature change rate, which is recorded as the axial power change rate; the positive and negative of the axial power change rate is opposite to the positive and negative of the axial temperature change rate; C3. Calculate the target power of each second annular heater 8 according to the axial power change rate, the axial position of each second annular heater 8 and the reference base power; from top to bottom, the target power of each second annular heater 8 changes according to the axial power change rate.

[0092] Specifically, in step C1, assuming that the height of the silicon steel coil 90 is H and the axial temperature change rate is Vz, then Vz=Tz / H.

[0093] Furthermore, in step C2, assuming that the axial power change rate is Wz, Wz can be calculated using the following formula: Wz=-K*Vz, where K is a positive proportional parameter.

[0094] Further, refer to Figure 8, the top of the silicon steel coil 90 is the axial position zero point, the axial position is positive when it is downward and negative when it is upward, the second annular heater 8 with a non-negative axial position is taken as an effective heater, and the second annular heater 8 with a negative axial position is taken as an invalid heater, and the invalid heater does not work (that is, the heating power is 0); in the figure, W0 is the reference reference power, the straight line L3 is a straight line with a slope equal to the axial power change rate Wz, L4 is a straight line with a constant heating power of W0, and the axial position corresponding to the intersection of L3 and L4 is the midpoint of the axial position of the effective heater (equal to the average value of the axial position h1 of the uppermost effective heater and the axial position hm of the lowermost effective heater, m is the total number of effective heaters), h1 to hm are the axial positions of each effective heater, respectively, W1_2 to Wm_2 are the heating power values ​​of the points corresponding to h1 to hm on the straight line L3 (W1_2 to Wm_2 can be calculated based on the straight line L3 and h1 to hm), as the target power of each effective heater.

[0095] Therefore, in step C3, each second annular heater 8 is divided into an effective heater and an ineffective heater according to the height H of the silicon steel coil 90 (a second annular heater 8 with a height higher than H is an ineffective heater, and a second annular heater 8 with a height not higher than H is an effective heater, and the height of the second annular heater 8 refers to the vertical distance from the central circular ring line of the second annular heater 8 to the top of the furnace bottom plate 2); the target power of the ineffective heater is set to 0, and the height of each effective heater is subtracted from the height H to obtain the axial position of each effective heater; Determine straight line L3 based on W0, h1 and hm, where the slope of straight line L3 is Wz and it passes through the point ((h1+hm) / 2, W0), and then calculate the vertical coordinate values ​​(heating power) of the points with horizontal coordinates h1 to hm on straight line L3 as the target power of each effective heater.

[0096] By adopting this method to adjust the target power, it is possible to ensure that the total heating power of the outside of the silicon steel coil 90 is the same as the reference total heating power when all effective heaters work at W0, and the heating power of the outside of the silicon steel coil 90 along the axial direction is gradually changed to effectively reduce the temperature deviation between the upper and lower ends; for example, when the axial temperature difference is negative (the upper end temperature is generally lower than the lower end temperature, so the axial temperature difference is usually negative), from top to bottom, the heating power of each effective heater gradually decreases, so that the heating speed of the upper end is increased and the heating speed of the lower end is reduced, thereby ensuring that the total heating power of the outside is stable and reducing the temperature deviation between the upper and lower ends.

[0097] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0098] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A silicon steel coil annealing furnace, comprising a furnace table (1), a furnace bottom plate (2), an inner cover (3), a heating cover (4) and an upper computer (5), wherein the furnace bottom plate (2) is placed on the top of the furnace table (1) and is used to support a silicon steel coil (90), the inner cover (3) is used to cover the silicon steel coil (90) on the inner side, and the heating cover (4) is used to cover the inner cover (3) on the inner side; characterized in that: The silicon steel coil annealing furnace further comprises a temperature sensor group (6); The top of the furnace (1) is provided with a plurality of first annular heaters (7) which are arranged concentrically and spaced apart from the inside to the outside, and the heating power of each of the first annular heaters (7) can be adjusted independently; the inner side of the heating cover (4) is provided with a plurality of second annular heaters (8) which are spaced apart from the top to the bottom, and the heating power of each of the second annular heaters (8) can be adjusted independently; The furnace table (1) is provided with an air intake structure (101) and an exhaust structure (102); the furnace bottom plate (2) is provided with a first through port (201) and a flow guide structure (202); the air intake structure (101), the flow guide structure (202), the first through port (201), the exhaust structure (102) and the inner cover (3) are used to cooperate and guide the protective gas to form an airflow, so that the airflow first flows from the inside to the outside along the furnace bottom plate (2), then flows upward along the gap between the silicon steel coil (90) and the inner cover (3), then flows from the upper side of the silicon steel coil (90) into the inner hole of the silicon steel coil (90), and finally flows out from the lower end of the inner hole of the silicon steel coil (90); The temperature sensor group (6) is used to detect the temperatures of the upper end, the lower end, the inner side and the outer side of the silicon steel coil (90); The host computer (5) is used to adjust the heating power of each of the first annular heaters (7) and each of the second annular heaters (8) according to the temperature measurement result of the temperature sensor group (6), so as to reduce the temperature deviation between the upper end and the lower end and between the inner side and the outer side of the silicon steel coil (90).

2. The silicon steel coil annealing furnace according to claim 1, characterized in that: The air intake structure (101) is used to guide the protective gas provided by the external air supply system to the middle of the top of the furnace table (1); The guide structure (202) is used to guide the protective gas flowing out from the middle of the top of the furnace platform (1) to flow along the furnace bottom plate (2) to the edge of the furnace bottom plate (2) and out to the gap between the silicon steel coil (90) and the inner cover (3); The first through opening (201) is arranged at the center of the furnace bottom plate (2), the exhaust structure (102) comprises an exhaust passage (103) connected to the top center of the furnace platform (1), and the first through opening (201) is used to connect the inner hole of the silicon steel coil (90) and the exhaust passage (103).

3. The silicon steel coil annealing furnace according to claim 2, characterized in that: The air intake structure (101) comprises a first annular air groove (104) provided in the middle of the top of the furnace table (1) and an air intake channel (105) connected to the first annular air groove (104); the air intake channel (105) is used to connect to an external air supply system so as to input the protective gas provided by the external air supply system into the first annular air groove (104).

4. The silicon steel coil annealing furnace according to claim 3, characterized in that: The guide structure (202) comprises a second annular air groove (203) and at least one guide channel (204); the second annular air groove (203) is provided at a position in the middle of the bottom of the furnace bottom plate (2) directly opposite to the first annular air groove (104); the guide channel (204) is provided at the bottom of or inside the furnace bottom plate (2); one end of the guide channel (204) is connected to the second annular air groove (203), and the other end extends to the edge of the furnace bottom plate (2) and is connected to the top edge of the furnace bottom plate (2).

5. The silicon steel coil annealing furnace according to claim 4, characterized in that: A downwardly protruding positioning ring is provided at the bottom edge of the furnace bottom plate (2); the inner diameter of the positioning ring is the same as the outer diameter of the top of the furnace platform (1); the positioning ring is used to be inserted into the top of the furnace platform (1) to position the furnace bottom plate (2).

6. The silicon steel coil annealing furnace according to claim 1, characterized in that: The inner cover (3) comprises a cylinder wall (301) and a cover body (302) arranged at the upper end of the cylinder wall (301); the upper and lower positions of the cover body (302) are adjustable.

7. The silicon steel coil annealing furnace according to claim 6, characterized in that: A heat-conducting pressure plate (303) is arranged inside the cover body (302), and the heat-conducting pressure plate (303) is used to abut against the upper end of the silicon steel coil (90) so as to transfer the heat of the inner cover (3) to the upper end of the silicon steel coil (90).

8. The silicon steel coil annealing furnace according to claim 7, characterized in that: The heat-conducting pressure plate (303) and the top wall of the cover body (302) form an air cavity (304); a second through port (305) is provided in the middle of the heat-conducting pressure plate (303); a plurality of air vents (306) are provided at the edge of the heat-conducting pressure plate (303); the second through port (305) is used to connect the air cavity (304) and the inner hole of the silicon steel coil (90); and the air vents (306) are used to connect the air cavity (304) and the gap between the cylinder wall (301) and the silicon steel coil (90).

9. A control method, characterized in that: The host computer (5) used in the silicon steel coil annealing furnace according to any one of claims 1 to 8 comprises the following steps: A1. Obtaining the temperatures of the upper end, lower end, inner side and outer side of the silicon steel coil (90) measured by the temperature sensor group (6); A2. Calculate the temperature difference between the upper end temperature and the lower end temperature of the silicon steel coil (90), recorded as the axial temperature difference; and calculate the temperature difference between the inner side temperature and the outer side temperature of the silicon steel coil (90), recorded as the radial temperature difference; A3. Adjust the heating power of each first annular heater (7) and each second annular heater (8) according to the axial temperature difference and the radial temperature difference to reduce the temperature deviation between the upper end and the lower end and between the inner side and the outer side of the silicon steel coil (90).

10. The control method according to claim 9, characterized in that: Step A3 includes: A301. Obtain the reference baseline line power of the first annular heater (7) according to the axial temperature difference; the line power is the heating power of the first annular heater (7) per unit length, and the reference baseline line power is the reference baseline value of the line power; A302. Obtaining a reference power of the second annular heater (8) according to the radial temperature difference; A303. Based on the reference baseline power, adjust the line power of each of the first annular heaters (7) according to the radial temperature difference, and calculate the target power of each of the first annular heaters (7) according to the adjusted line power; A304. On the basis of the reference power, adjusting the power of each of the second annular heaters (8) according to the axial temperature difference to obtain a target power of each of the second annular heaters (8); A305. Adjust the heating power of each of the first annular heaters (7) and each of the second annular heaters (8) to the corresponding target power.

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