Electromagnetic induction heating apparatus, control method, and slab production line

Abstract

The application discloses an electromagnetic induction heating device, a control method and a slab production line. The device comprises an upper induction head and a lower induction head. The upper induction head and the lower induction head each comprise a shell, a coil, a controller, a first magnetic guide assembly, a second magnetic guide assembly and a third magnetic guide assembly arranged along the length direction of the coil in sequence. The first magnetic guide assembly and the third magnetic guide assembly each comprise a first magnetic guide body matched with the coil and a driving mechanism. The second magnetic guide assembly comprises a second magnetic guide body matched with the coil. The controller controls the first magnetic guide body to move up and down through the driving mechanism according to the temperature of the region on the slab to be heated corresponding to the first magnetic guide body and a target temperature, adjusts the gap between the first magnetic guide body and the slab to be heated, and further adjusts the heating temperature of the corresponding region of the slab to be heated, so as to realize the temperature uniformity in the width direction of the slab. The application improves the heating efficiency of the device and the temperature uniformity in the width direction of the slab.

Description

Technical Field

[0001] This invention belongs to the field of slab heating technology, and particularly relates to an electromagnetic induction heating device, a control method, and a slab production line. Background Technology

[0002] In the wave of green transformation in the steel industry, short-process steelmaking, with its numerous advantages such as high efficiency, energy saving, and environmental protection, is gradually becoming the mainstream trend in industry development. This trend has not only driven innovation in steel production processes but also brought new opportunities and challenges to the development of related supporting technologies, among which the application of induction heating technology in short-process steelmaking is particularly important. The core of short-process steelmaking lies in integrating the relatively independent and dispersed processes of smelting, casting, heating, and rolling in traditional steel manufacturing processes to achieve continuous steel production. This transformation makes the production process more compact and significantly improves production efficiency, while also placing higher demands on heating technology. Induction heating technology, with its unique advantages, perfectly meets the needs of short-process steelmaking. It can achieve rapid heating and precise control, with no oxidation or decarburization during the heating process; it offers high heating quality, is environmentally friendly, and has significant energy-saving and emission-reduction effects; it has fast heating speed and high efficiency; the equipment is small in size, saves space, and improves working conditions. These advantages have led to the widespread application of induction heating technology in short-process steelmaking, making it a key technological support for the development of short-process steelmaking.

[0003] In induction heating technology, transverse magnetic field heating and longitudinal magnetic field heating are two main heating methods. Compared to longitudinal magnetic field heating, transverse magnetic field heating has many significant advantages:

[0004] First, longitudinal magnetic field heating uses a coil in the form of a spiral tube. When the slab passes through the closed channel of the heater, an induced current is generated and it is heated. Since the closed channel of the longitudinal magnetic field has a fixed size, the deformation of the slab can easily damage the inductor. In contrast, transverse magnetic field heating includes induction heaters distributed vertically, with no other equipment or components on the left or right. This open channel structure avoids damage to the inductor caused by slab deformation (such as warping, deformation, or jumping) during longitudinal magnetic field heating, thereby greatly reducing the risk of equipment damage, reducing maintenance frequency, ensuring production continuity, and reducing labor intensity and production costs.

[0005] Secondly, during longitudinal magnetic field heating, the induced current on the slab forms a circulating current on the surface of the thick section. This results in a similar temperature distribution of the slab before and after heating (lower temperature at the edges and higher temperature in the center along the width), indicating that temperature non-uniformity still exists. Furthermore, when the slab thickness is thin, higher heating frequency is required to ensure heating efficiency, significantly increasing the investment cost of the heating equipment. Due to the magnetic field distribution characteristics of transverse magnetic field heating, heat can be transferred more evenly to all parts of the slab during the heating process, achieving more uniform slab heating, reducing performance differences caused by uneven heating, and improving product quality stability. Moreover, the frequency requirement is lower, and the equipment investment cost is significantly reduced.

[0006] Furthermore, transverse magnetic field heating allows for flexible adjustment of the position and arrangement of induction heaters according to different slab specifications and production needs, achieving optimal heating effects and meeting the requirements for temperature uniformity. This provides strong support for short-process steelmaking to produce steel of different specifications. However, despite the numerous advantages of transverse magnetic field heating, some problems still need to be addressed in the actual slab heating process, particularly regarding heating efficiency and temperature uniformity.

[0007] (1) Heating efficiency issues. Although transverse magnetic field heating improves heating efficiency to some extent compared to longitudinal magnetic field heating, there is still room for improvement when dealing with slabs of different materials, thicknesses, and widths. For example, for some high-strength, high-toughness steel slabs, due to their relatively poor thermal conductivity, transverse magnetic field heating is difficult to bring them to the ideal heating temperature in a short time, which affects production efficiency.

[0008] (2) Temperature uniformity issues. Although transverse magnetic field heating can achieve relatively uniform heating overall, temperature deviations may still occur in local areas, such as the edges and corners of the slab. This temperature non-uniformity may lead to dimensional deviations and inconsistent performance of the slab during subsequent rolling processes, affecting the quality of the final product.

[0009] In conclusion, the importance of induction heating technology under the trend of short-process steelmaking is self-evident, and transverse magnetic field heating plays a key role in short-process steelmaking due to its unique advantages. However, the problems of heating efficiency and temperature uniformity in the process of heating slabs by transverse magnetic field heating must be taken seriously and solved.

[0010] Patent document CN114981455A discloses a transverse magnetic field induction heating device. Symmetrical upper and lower transverse inductors are arranged on the upper and lower surfaces of a metal strip. Specifically, the transverse induction coil is designed with different shapes at both ends; one end is a trapezoidal semicircle. This unique end shape allows for better control of temperature uniformity across the strip width. However, because the magnetic field lines generated by the coil form a loop in the air, losses are extremely high, resulting in a significant reduction in heating efficiency.

[0011] Patent document CN111278182A discloses an alternating transverse and longitudinal magnetic induction heating system and method, which ensures temperature uniformity of different parts of the slab after heating by alternating the transverse and longitudinal magnetic fields. However, due to some inherent defects of the longitudinal magnetic field, such as the possibility of the equipment being damaged by the slab warping, and the difficulty in achieving good matching and satisfaction of the same set of equipment when it is necessary to produce slabs of various specifications, the combination of longitudinal and transverse magnetic fields brings greater complexity to the control of the entire heating production line, and the convenience and versatility of equipment maintenance and interchangeability are also insufficient.

[0012] Patent document CN117336909A discloses a device and method for improving the heating uniformity and heating efficiency of continuously cast and rolled slabs. By setting magnetic poles in the energized coil, the loss of magnetic field in the air is reduced. The temperature is controlled by adjusting the mutual misalignment of the front and rear coils and the misalignment of the upper and lower coils. This makes the entire device very complex and large, which brings great inconvenience to on-site operation, control and maintenance. In terms of temperature uniformity control, due to the strong magnetic pole concentration, it is very difficult to eliminate the temperature difference at the edge, and temperature uniformity is difficult to guarantee. Summary of the Invention

[0013] The purpose of this invention is to provide an electromagnetic induction heating device, a control method, and a slab production line to improve the heating efficiency of the heating device and the temperature uniformity in the width direction of the slab.

[0014] The present invention solves the above-mentioned technical problems through the following technical solution: an electromagnetic induction heating device, comprising an upper induction head and a lower induction head, wherein both the upper induction head and the lower induction head include a housing and a coil disposed within the housing;

[0015] Both the upper and lower sensing heads further include a controller, and a first magnetic conductive assembly, a second magnetic conductive assembly, and a third magnetic conductive assembly arranged sequentially along the length of the coil. The first and third magnetic conductive assemblies correspond to the two side edges of the blank to be heated, respectively, and the second magnetic conductive assembly corresponds to the middle of the blank to be heated. The first and third magnetic conductive assemblies each include a first magnetic conductor that cooperates with the coil and a driving mechanism for moving the first magnetic conductor. The second magnetic conductive assembly includes a second magnetic conductor that cooperates with the coil and is disposed on the outer casing.

[0016] The controller is used to control the movement of the first magnetic conductor through a drive mechanism based on the temperature of the area corresponding to the first magnetic conductor on the slab to be heated and the target temperature, thereby adjusting the gap between the first magnetic conductor and the slab to be heated, and thus adjusting the heating temperature of the area corresponding to the slab to be heated, so as to achieve temperature uniformity in the width direction of the slab.

[0017] Furthermore, the number of the first magnetic conductive component and the third magnetic conductive component are equal and there are multiple of each, and each first magnetic conductive component or each third magnetic conductive component corresponds to a region in the width direction of the slab to be heated.

[0018] Furthermore, grooves that mate with the coil are formed at the bottom of the first and second magnetic conductors, and the long side of the coil passes through the grooves of the first and second magnetic conductors.

[0019] Furthermore, when each long side cross section of the coil corresponds to a different groove of the first magnetic conductor and / or the second magnetic conductor, the first width is greater than or equal to twice the second width; wherein, the first width refers to the width of the magnetic conductor between two adjacent grooves of the first magnetic conductor and / or the second magnetic conductor, and the second width refers to the width of the outermost groove's outer wall of the magnetic conductor.

[0020] Furthermore, the drive mechanism includes a servo hydraulic cylinder, the piston rod of which passes through the housing and is connected to the first magnetic conductor.

[0021] Furthermore, the second magnetic conductor is disposed on the outer shell via a connecting assembly, the connecting assembly including an insulating bolt and an insulating block, one end of the insulating bolt being disposed on the second magnetic conductor and the other end being disposed on the outer shell, and the insulating block being located between the second magnetic conductor and the outer shell and sleeved on the insulating bolt.

[0022] Furthermore, a first potting layer is provided outside the coil, and a second potting layer is provided on the inner wall of the outer casing, with the first potting layer and the second potting layer forming an integral whole.

[0023] Preferably, a heat-insulating buffer layer is provided between the bottom of the first magnetic conductor and the second potting layer on the bottom surface of the outer casing.

[0024] Based on the same concept, the present invention provides a slab production line, wherein the production line is equipped with the electromagnetic induction heating equipment as described above.

[0025] Based on the same concept, the present invention provides a control method for the electromagnetic induction heating device as described above, comprising:

[0026] Before the slab enters the electromagnetic induction heating equipment, the detection temperature of each region in the width direction of the slab is obtained;

[0027] Calculate the temperature difference between each region based on the detected temperature and the target temperature of each region along the width of the slab.

[0028] The movement of the first magnetic conductor corresponding to each region is controlled according to the temperature difference of each region, and the gap between the first magnetic conductor and the slab is adjusted, thereby adjusting the heating temperature of that region and achieving temperature uniformity in the width direction of the slab.

[0029] Furthermore, for the first to N-M electromagnetic induction heating devices, the formula for calculating the target temperature of each region along the width of the slab is as follows:

[0030]

[0031] Among them, T j T represents the target temperature of the i-th region along the width direction of the slab. r T represents the temperature required for slab rolling. ej The temperature of the i-th region in the width direction of the slab at the entrance of the heating zone is represented by N, the number of electromagnetic induction heating devices is represented by M, and M < N.

[0032] For the N-M+1th to the Nth electromagnetic induction heating equipment, the formula for calculating the target temperature of each region along the width of the slab is as follows:

[0033]

[0034] Where, ΔT j This represents the natural heat dissipation temperature drop of the i-th region along the width of the slab from the entrance of the heating zone to the entrance of the rolling zone.

[0035] Beneficial effects

[0036] Compared with the prior art, the advantages of the present invention are as follows:

[0037] The electromagnetic induction heating device of this invention adopts a combination design of coil and magnetic conductor. The first magnetic conductor at both ends of the coil is movable. The gap between the first magnetic conductor and the slab is adjusted by adjusting the up and down movement of the first magnetic conductor through a drive mechanism, thereby adjusting the magnetic flux. The magnitude of the induced current on the slab is adjusted by controlling the magnetic flux, thereby adjusting the heating temperature of each area in the width direction of the slab. This achieves uniform temperature control throughout the width of the slab, improving product quality and yield. At the same time, since the first magnetic conductor is movable, the loss of magnetic lines of force is reduced, greatly improving heating efficiency, increasing energy utilization, and reducing heating costs.

[0038] Heating temperature can be controlled by adjusting the first magnetic conductor inside the upper and lower induction heads, avoiding the overall movement of the upper and lower induction heads, and eliminating the need for misalignment between adjacent electromagnetic induction heating devices on a production line. The structure is more compact, the control precision is higher, and the complexity is lower.

[0039] The first and second magnetic conductors are made of soft magnetic composite materials, which concentrates the magnetic field generated by the coil in the soft magnetic composite material with high relative permeability and low magnetic resistance. Compared with the case without magnetic conductors, the magnetic field loss of the present invention is greatly reduced, the magnetic field utilization rate is greatly improved, and the heating power consumption and cost are reduced. Attached Figure Description

[0040] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a cross-sectional view of the arrangement of the electromagnetic induction heating device and the first magnetic conductive component or the third magnetic conductive component in an embodiment of the present invention;

[0042] Figure 2 This is a cross-sectional view of the second magnetically conductive component in an embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of a rectangular coil formed using an O-shaped winding method in an embodiment of the present invention;

[0044] Figure 4 This is a schematic diagram of a rectangular coil formed using a figure-eight winding method in an embodiment of the present invention;

[0045] Figure 5 This is an embodiment of the present invention. Figure 3The diagram shows the cross-section of the long side of the rectangular coil corresponding to different grooves of the first magnetic conductor; where b represents the width of the first magnetic conductor between two adjacent grooves, a represents the width of the outer wall of the magnetic conductor of the outermost groove, e represents the distance between the coil and the first magnetic conductor, d represents the distance between the groove and the top surface of the first magnetic conductor, c represents the maximum stroke of the first magnetic conductor, and h1 represents the margin and is greater than 0.

[0046] Figure 6 This is an embodiment of the present invention. Figure 3 The diagram shows the cross-section of the long side of the rectangular coil corresponding to the same groove of the first magnetic conductor;

[0047] Figure 7 This is an embodiment of the present invention. Figure 4 The diagram shows the cross-section of the long side of the rectangular coil corresponding to different grooves of the first magnetic conductor, with both outer walls of the outermost groove being magnetic conductors.

[0048] Figure 8 This is an embodiment of the present invention. Figure 4 The diagram shows the cross-section of the long side of the rectangular coil corresponding to different grooves of the first magnetic conductor, with the outermost groove having a magnetic conductor on one side and no outer wall on the other side.

[0049] Figure 9 These are magnetic field lines paths with different matching forms between the coil and the first and second magnetic conductors in embodiments of the present invention;

[0050] Figure 10 These are the temperature curves of the slab before and after induction heating in this embodiment of the invention.

[0051] Figure 11 This is the temperature uniformity curve in the width direction of the slab in this embodiment of the invention.

[0052] Explanation of reference numerals in the attached drawings: 100-Upper induction head, 110-First magnetic conductor, 120-Outer shell, 121-Second potting layer, 122-Heat insulation buffer layer, 130-Coil, 131-First potting layer, 140-Servo hydraulic cylinder, 150-Hydraulic controller, 160-Second magnetic conductor, 161-Insulating bolt, 162-Insulating block, 200-Lower induction head, 300-Slab, 400-Transfer roller. Detailed Implementation

[0053] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] The technical solutions of this application will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0055] Example 1

[0056] like Figure 1 and Figure 2 As shown, the electromagnetic induction heating device provided in this embodiment of the invention includes an upper induction head 100 and a lower induction head 200. The upper induction head 100 and the lower induction head 200 are symmetrically arranged about the thickness center line of the slab 300 as the axis of symmetry. The width direction of the upper induction head 100 and the lower induction head 200 (i.e., the width direction of the coil 130) is consistent with the conveying direction of the slab 300, and the length direction of the upper induction head 100 and the lower induction head 200 (i.e., the length direction of the coil 130) is consistent with the width direction of the slab 300. Both the upper sensing head 100 and the lower sensing head 200 include a housing 120, a coil 130 disposed within the housing 120, a controller, and a first magnetic conductive assembly, a second magnetic conductive assembly, and a third magnetic conductive assembly arranged sequentially along the length of the coil 130. The first and third magnetic conductive assemblies correspond to the two sides of the slab, respectively, so that the first and third magnetic conductive assemblies and the coil 130 achieve induction heating of the two sides of the slab. The second magnetic conductive assembly corresponds to the middle of the slab, so that the second magnetic conductive assembly and the coil 130 achieve induction heating of the middle of the slab. The first and third magnetic conductive assemblies are located at both ends of the length of the coil 130 and each includes a first magnetic conductor 110 that cooperates with the coil 130 and a driving mechanism for driving the first magnetic conductor 110 to move up and down. The second magnetic conductive assembly is located in the middle of the length of the coil 130 and includes a second magnetic conductor 160 that cooperates with the coil 130 and is disposed on the housing 120.

[0057] The drive mechanisms of the first and third magnetic conductive components are electrically connected to the controller. Based on the temperature of the area on the slab to be heated corresponding to the first magnetic conductor 110 and the target temperature, the controller controls the first magnetic conductor 110 to move up and down via the drive mechanism, adjusting the gap between the first magnetic conductor 110 and the slab to be heated, thereby adjusting the heating temperature of the corresponding area of ​​the slab and achieving temperature uniformity in the width direction of the slab. During the up and down movement of the first magnetic conductor 110, it does not contact the outer casing 120 at its upper and lower limit positions.

[0058] In a specific embodiment of the present invention, the number of the first magnetic conductive component and the third magnetic conductive component are equal and there are multiple of each. Each first magnetic conductive component or each third magnetic conductive component corresponds to a region in the width direction of the slab to be heated.

[0059] The slab is divided into regions along its width. The middle region corresponds to the second magnetic conductor 160 of the second magnetic component, while the two outer regions correspond to the first and third magnetic components, respectively. When there are multiple first and third magnetic components, the outer regions are divided into multiple sub-regions, each corresponding to a first magnetic conductor 110 of either the first or third magnetic component. The more regions divided along the slab's width, the more first magnetic conductors 110 there are, resulting in more precise temperature control in each region and better temperature uniformity along the slab's width.

[0060] The first magnetic conductive assembly, the second magnetic conductive assembly, and the third magnetic conductive assembly are arranged along the length of the coil 130. The width of the blank is adapted to the inner length of the coil 130, that is, the length of the magnetic conductive body arranged on the coil 130 is adapted to the width of the blank. The first magnetic conductive body 110 on both sides of the coil 130 corresponds to the edge of the blank, and the second magnetic conductive body 160 in the middle of the coil 130 corresponds to the middle area of ​​the blank.

[0061] In a specific embodiment of the present invention, both the first magnetic conductor 110 and the second magnetic conductor 160 are made of soft magnetic composite material. Soft magnetic composite material has good magnetic permeability and high magnetic saturation. Most importantly, even under medium and high frequency operating conditions, its induced eddy currents are small and the heat generation is negligible, which can greatly simplify the cooling water circuit of the entire heating device. The magnetic conductors of this type of heating device do not require water cooling.

[0062] The first magnetic conductor 110 and the second magnetic conductor 160 are engaged with the coil 130 in the same way. In a specific embodiment of the present invention, grooves that engage with the coil 130 are provided at the bottom of the first magnetic conductor 110 and the second magnetic conductor 160, and the long side of the coil 130 passes through the grooves of the first magnetic conductor 110 and the second magnetic conductor 160.

[0063] In this embodiment, the coil 130 is formed by winding a copper tube. The coil 130 is rectangular in shape. A rectangular coil reduces the change in magnetic flux at the arc transition and ensures that the second magnetic conductor 160 and the first magnetic conductor 110 are consistent in shape. The coil 130 can be formed into a rectangular coil using an O-shaped winding method, such as... Figure 3 As shown; a rectangular coil can also be formed using a figure-eight winding method, such as... Figure 4 As shown. Figure 4 In this process, the left and right parts of a rectangular coil are connected in series using an 8-shaped winding method. After being connected in series, they share a shielding cover on the outside of the coil for magnetic shielding. At the same time, the magnetic fields generated by the left and right parts are in opposite directions.

[0064] Arranging magnetic conductors along the magnetic field lines generated by coil 130 serves to concentrate the magnetism. The more magnetic conductors arranged in the magnetic field loop, the smaller the magnetic field loss and the higher the energy utilization rate. Based on this, there are various matching methods between coil 130 and the first magnetic conductor 110 and the second magnetic conductor 160, such as... Figures 5 to 7 As shown.

[0065] for Figure 3 In the first embodiment of the rectangular coil shown, the two long sides of the coil 130 pass through two different grooves of the first magnetic conductor 110 and the second magnetic conductor 160, respectively. That is, the cross-sections of the two long sides of the coil 130 correspond to two different grooves of the first magnetic conductor 110 and the second magnetic conductor 160, respectively. Figure 5 As shown; in the second embodiment, the two long sides of the coil 130 pass through the same groove of the first magnetic conductor 110 and the second magnetic conductor 160, that is, the cross-sections of the two long sides of the coil 130 correspond to the same groove of the first magnetic conductor 110 and the second magnetic conductor 160, as shown. Figure 6 As shown.

[0066] for Figure 5 The matching configuration of coil 130 with the first magnetic conductor 110 and the second magnetic conductor 160 is shown in the figure below. Figure 9 As shown, due to the relatively larger arrangement of magnetic conductors along the magnetic field path, the magnetic field loss is relatively smaller, resulting in relatively higher efficiency. However, this structural form leads to a relatively smaller winding space for coil 130, fewer turns, and a relatively smaller number of magnetic field lines generated. For Figure 6 The matching configuration of coil 130 with the first magnetic conductor 110 and the second magnetic conductor 160 is shown in the figure below. Figure 9 As shown, the winding space of coil 130 is larger (compared to...). Figure 5 Compared to the matching form, coil 130 has the same number of layers, but more turns can be wound in a single layer. However, since there is no magnetic conductor in the inner ring of coil 130, there is an air path in the magnetic field line path, resulting in relatively large magnetic field loss.

[0067] for Figure 4 The rectangular coil shown has three long sides (the two middle long sides merged into one) that pass through three different grooves in the first magnetic conductor 110 and the second magnetic conductor 160. The outer walls on both sides of the two outermost grooves of the first magnetic conductor 110 and the second magnetic conductor 160 can both be magnetic materials (e.g., Figure 7 As shown), it can also have a magnetic conductor on one side and no outer wall on the other side (such as...). Figure 8 (As shown). Figure 8 In the middle, the width of the outermost groove is f, f is greater than or equal to 0, the main path of the magnetic field lines is in the inner ring of the coil 130, and the outer path is shielded by the outer shell 120.

[0068] for Figure 7 The matching configuration of coil 130 with the first magnetic conductor 110 and the second magnetic conductor 160 is shown in the figure below. Figure 9 As shown, due to the relatively larger arrangement of magnetic conductors along the magnetic field path, the magnetic field loss is relatively smaller, resulting in relatively higher efficiency. However, this structural form leads to a relatively smaller winding space for coil 130, fewer turns, and a relatively smaller number of magnetic field lines generated. For Figure 8 The matching configuration of coil 130 with the first magnetic conductor 110 and the second magnetic conductor 160 is shown in the figure below. Figure 9 As shown, the winding space of coil 130 is larger (compared to...). Figure 7 Compared to the matching form, coil 130 has the same number of layers, but a single layer can be wound with more turns. However, since there is no magnetic conductor on the outer ring of coil 130, there is an air path in the magnetic field line path, resulting in relatively large magnetic field loss.

[0069] When each long side cross section of coil 130 corresponds to a different groove in the first magnetic conductor 110 and / or the second magnetic conductor 160 (e.g. Figure 5 and Figure 7 As shown, the first width b is greater than or equal to twice the second width a; where the first width b refers to the width of the magnetic conductor between two adjacent grooves of the first magnetic conductor 110 and / or the second magnetic conductor 160, and the second width a refers to the width of the outermost groove's outer wall of the magnetic conductor (i.e., the width of the outer wall with the magnetic conductor as the outer wall of the groove, and this outer wall being the outermost wall surface). This dimensional constraint ensures that the magnetic lines of force in the middle of the coil 130 all pass through the magnetic conductor when they disperse to both sides, without entering the air, reducing the loss of the magnetic field in the air, improving the magnetic field utilization rate, and improving the heating efficiency.

[0070] To ensure the normal vertical movement of the first magnetic conductor 110, such as Figure 5 As shown, the distance c+h1 between the bottom surface of the coil 130 and the bottom surface of the first magnetic conductor 110 is greater than the maximum stroke c of the first magnetic conductor 110, and the distance c+h2 between the top surface of the first magnetic conductor 110 and the inner wall of the outer shell 120 is greater than the maximum stroke c of the first magnetic conductor 110. Here, h1 and h2 both represent margins and are greater than zero, which ensures that the magnetic lines of force generated by the coil 130 are better concentrated in the magnetic conductor, reducing the divergence and loss of the magnetic field.

[0071] The number of turns in coil 130 is greater than or equal to 2, and the number of layers in coil 130 is greater than or equal to 2. When coil 130 has multiple turns and multiple layers... Figures 5 to 8 The dimension from coil 130 to a certain point is the dimension from the side of coil 130 closest to that point to that point. For example, Figures 5 to 8In the above, when the coil 130 has two layers, c+h1 represents the distance between the bottom surface of the lower layer of the coil 130 and the bottom surface of the first magnetic conductor 110, rather than the distance between the bottom surface of the upper layer of the coil 130 and the bottom surface of the first magnetic conductor 110.

[0072] The drive mechanism is either hydraulically driven or electrically driven. When electrically driven, the drive mechanism includes a drive motor and a linear motion mechanism. The drive motor controls the linear motion mechanism to move linearly, thereby driving the first magnetic conductor 110 to move up and down. When hydraulically driven, the drive mechanism includes a servo hydraulic cylinder 140. The piston rod of the servo hydraulic cylinder 140 passes through the housing 120 and is connected to the first magnetic conductor 110. The controller is a hydraulic controller 150. To ensure smooth up-and-down movement of the first magnetic conductor 110, two servo hydraulic cylinders 140 are configured for each first magnetic conductor 110. The two servo hydraulic cylinders 140 are symmetrically arranged about the center line of the first magnetic conductor 110, and are synchronously controlled by the same hydraulic controller 150, ensuring that the first magnetic conductor 110 does not jam during up-and-down movement.

[0073] The displacement accuracy of the first magnetic conductor 110 controlled by hydraulic drive can reach 0.1mm, which has high control accuracy for strengthening and weakening the magnetic field, better temperature uniformity control effect, and improved control accuracy.

[0074] In a specific embodiment of the present invention, the second magnetic conductor 160 is disposed on the housing 120 via a connecting assembly, such as... Figure 2 As shown, the connecting assembly includes an insulating bolt 161 and an insulating block 162. One end of the insulating bolt 161 is disposed on the second magnetic conductor 160, and the other end is disposed on the outer casing 120. The insulating block 162 is located between the second magnetic conductor 160 and the outer casing 120 and is sleeved on the insulating bolt 161. The insulating bolt 161 is a non-magnetic, high-strength insulating bolt, and the insulating block 162 ensures that the second magnetic conductor 160 and the outer casing 120 do not directly contact each other.

[0075] In a specific embodiment of the present invention, a first potting layer 131 is provided outside the coil 130, and a second potting layer 121 is provided on the inner wall of the outer shell 120. The first potting layer 131 and the second potting layer 121 form an integral whole.

[0076] After the coil 130 is pre-formed, it forms an integral unit with the first potting layer 131. This integral unit, after assembly with the first magnetic conductor 110 and the second magnetic conductor 160, positions the coil 130 within the grooves of the first and second magnetic conductors 110 and 160. The first potting layer 131 encapsulates the coil 130 and maintains a certain thickness, ensuring insulation between the coil 130 and the first and second magnetic conductors 110 and 160. The thickness of the first potting layer 131 is related to the operating voltage of the electromagnetic induction heating device; the higher the operating voltage, the greater the thickness of the first potting layer 131. Simultaneously, the thickness of the first potting layer 131 closest to the first and second magnetic conductors 110 and 160 is less than the distance e between the coil 130 and the first and second magnetic conductors 110 and 160, ensuring smooth vertical movement of the first magnetic conductor 110.

[0077] The second potting layer 121 is disposed on the bottom and side surfaces of the outer casing 120 and forms an integral part with the first potting layer 131. To ensure the integrity of the potting layer and the outer casing 120, anchoring pins can be used to connect the second potting layer 121 and the outer casing 120, bearing the overall weight of the coil 130, the first potting layer 131, and the second potting layer 121. The first potting layer 131 and the second potting layer 121 are provided with a certain thickness to ensure structural strength. During the up-and-down movement of the first magnetic conductor 110, the first magnetic conductor 110 does not contact the second potting layer 121 on the bottom surface of the outer casing 120 at the lower limit position.

[0078] In a specific embodiment of the present invention, a heat-insulating buffer layer 122 is provided between the bottom of the first magnetic conductor 110 and the second potting layer 121 on the bottom surface of the outer shell 120. The heat-insulating buffer layer 122 is resistant to high temperature, which not only isolates the heat radiation of the heated slab, but also prevents the first magnetic conductor 110 from direct contact with the second potting layer 121 and from being damaged by mutual impact.

[0079] The slab production line provided in this embodiment of the invention is equipped with the electromagnetic induction heating equipment of this embodiment. Multiple electromagnetic induction heating devices are arranged along the conveying direction of the slab. The number of electromagnetic induction heating devices is determined according to the slab production capacity of the production line and the target temperature to be achieved. Each electromagnetic induction heating device is the same, ensuring interchangeability.

[0080] Example 2

[0081] During the continuous casting and forming process, heat is continuously dissipated from the slab. Furthermore, the heat dissipation rate at the edges and corners of the slab is greater than that at the center along the width direction. Before reaching the induction heating zone, the temperature along the width of the slab already shows a pattern of lower temperatures at the edges and higher temperatures at the center, as indicated by the temperature curve shown below. Figure 10As shown in the left figure, the temperatures of the AB segment on the left side of the slab width direction and the CD segment on the right side of the slab width direction are symmetrical. However, due to the different continuous casting processes and the different specifications of the slabs produced, the high and low temperature differences between the AB and CD segments are also different.

[0082] Even if the temperature of the slab is uniform along its width before it enters the induction heater, after being heated by an induction heater (without a moving magnetic conductor), the temperature of the slab will show a difference: the temperature is higher at both ends of the slab's width, while the temperature near the edges (towards the center) is lower. Figure 10 As shown in the right figure. This is because the inner coil length (excluding the dimensions of each turn and the gap between turns) is slightly larger than the width of the slab, resulting in an edge effect, which causes the edge temperature to be △T1 higher than the center temperature. Under the same heating power, and due to the different thicknesses of the slab, the degree of edge overheating also varies; the thinner the slab, the higher the edge overheating temperature.

[0083] In reality, because the temperature at the edges of the slab is too low when it enters the induction heater, the overall temperature of the slab increases after passing through the induction heater (for example, the temperature in the middle of the slab increases by ΔT2). The excessive temperature rise at the edges compensates for the low initial temperature, and when passing through multiple sets of induction heaters, the edge temperature may exceed the middle temperature. Furthermore, because there is a low-temperature zone near the center at the edges, uneven temperature distribution occurs across the entire width.

[0084] If the inner coil length is slightly less than the width of the slab, there will be no edge effect, and thus no situation where the edge temperature in the width direction of the slab exceeds the middle temperature. However, there will still be a low temperature zone near the center at the edge, which will also lead to uneven temperature in the entire width direction.

[0085] To address the aforementioned technical problems, this invention provides a control method for an electromagnetic induction heating device, applied to the electromagnetic induction heating device in Embodiment 1 of this invention. First magnetic conductors, movable vertically, are positioned at both ends of the coil along its length, while a fixed second magnetic conductor is positioned at the middle of the coil. The first magnetic conductors at both ends correspond to the two sides of the slab, and the second magnetic conductor in the middle corresponds to the middle of the slab. Induction heating of the slab's edges is achieved through the interaction of the first magnetic conductors and the coil, and similarly, induction heating of the slab's edges is achieved through the interaction of the second magnetic conductor and the coil. Since the first magnetic conductors can move vertically, the gap between the first magnetic conductor and the slab can be adjusted by controlling their vertical movement, thereby adjusting the heating temperature or heating rate of the slab's edges and achieving temperature uniformity along the width of the slab.

[0086] like Figure 10As shown in the right figure, when the length of the magnetic conductor arranged along the length of the coil is greater than the width of the slab, an edge effect occurs, resulting in a higher temperature at the outermost edge than in the middle, and a low-temperature zone appearing near the middle edge. When the length of the magnetic conductor arranged along the length of the coil is less than or equal to the width of the slab, there is no edge effect, but the phenomenon of a low-temperature zone near the middle edge still exists. Therefore, multiple first magnetic conductor components (corresponding to...) are used. Figure 10 The right figure shows the width of L1 and multiple second magnetic components (corresponding to...). Figure 10 (L2 width in the right figure) The first magnetic conductor of each first magnetic component or second magnetic component corresponds to a region on the edge of the slab width direction, realizing the individual adjustment of the heating temperature of the region, thereby achieving temperature uniformity throughout the width direction of the slab.

[0087] The control method includes the following steps:

[0088] Step S1: Before the slab enters the electromagnetic induction heating equipment, the detection temperature of each region in the width direction of the slab is obtained;

[0089] Step S2: Calculate the temperature difference between each region based on the detected temperature and target temperature of each region along the width of the slab;

[0090] Step S3: Control the movement of the first magnetic conductor corresponding to each region according to the temperature difference of each region, adjust the gap between the first magnetic conductor and the slab, and thus adjust the heating temperature of the region to achieve temperature uniformity in the width direction of the slab.

[0091] In step S1, a scanning temperature meter is used to detect the temperature along the entire width of the slab, i.e., to obtain the detected temperature of each region along the width of the slab. When the detected temperature of each region is lower than its target temperature, the first magnetic conductor in that region is controlled to move downward, reducing the gap between the first magnetic conductor and the slab, increasing the magnetic flux in that region, thereby increasing the magnitude of the induced current in that region, raising the heating temperature in that region, and increasing the temperature rise rate in that region. When the detected temperature of each region is higher than its target temperature, the first magnetic conductor in that region is controlled to move upward, increasing the gap between the first magnetic conductor and the slab, reducing the magnetic flux in that region, thereby reducing the magnitude of the induced current in that region, lowering the heating temperature in that region, and reducing the temperature rise rate in that region.

[0092] Before the slab enters each electromagnetic induction heating device, the temperature in the width direction of the slab is detected, and the corresponding electromagnetic induction heating device is controlled according to the temperature detection results until the last electromagnetic induction heating device, at which point the temperature in the width direction of the slab tends to be uniform.

[0093] For each electromagnetic induction heating device, the target temperature of each region along the width of the slab is equal to the sum of the first temperature and the second temperature of that region. The first temperature of each region is equal to the ratio of the difference between the required rolling temperature of the slab and the temperature at the entrance of the heating zone to that region to the number of electromagnetic induction heating devices. In other words, the difference between the required rolling temperature and the temperature at the entrance of the heating zone is evenly distributed among the electromagnetic induction heating devices for compensation. The second temperature of each region is equal to the ratio of the natural heat dissipation temperature drop from the entrance of the heating zone to the entrance of the rolling zone to the number of electromagnetic induction heating devices participating in the natural heat dissipation temperature drop compensation. In other words, the natural heat dissipation temperature drop from the entrance of the heating zone to the entrance of the rolling zone is evenly distributed among the electromagnetic induction heating devices participating in the natural heat dissipation temperature drop compensation.

[0094] There is a certain distance between the heating zone and the rolling zone. Heat exchange still occurs during the transfer of the slab from the heating zone to the rolling zone, resulting in uneven temperature distribution where the edges of the slab are cooler and the center is warmer. Therefore, it is necessary to compensate for the natural heat dissipation temperature drop during induction heating. The higher the slab temperature, the faster the heat dissipation rate and the greater the power consumption. To reduce energy consumption while compensating for the natural heat dissipation temperature drop, the first N-M electromagnetic induction heating devices do not participate in the natural heat dissipation temperature drop compensation; instead, the last M electromagnetic induction heating devices participate in the natural heat dissipation temperature drop compensation.

[0095] For the first to N-M electromagnetic induction heating devices, the formula for calculating the target temperature of each region along the width of the slab is as follows:

[0096]

[0097] Among them, T j T represents the target temperature of the i-th region along the width direction of the slab. r T represents the temperature required for slab rolling. ej The value represents the temperature of the i-th region in the width direction of the slab at the entrance of the heating zone, N represents the number of electromagnetic induction heating devices, and M represents the number of electromagnetic induction heating devices participating in the natural heat dissipation temperature drop compensation.

[0098] For the N-M+1th to the Nth electromagnetic induction heating equipment, the formula for calculating the target temperature of each region along the width of the slab is as follows:

[0099]

[0100] Where, ΔT j This represents the natural heat dissipation temperature drop of the i-th region along the width of the slab from the entrance of the heating zone to the entrance of the rolling zone.

[0101] Because heat dissipates quickly at the edges of the slab, the final compensation temperature at the edges is higher than that in the center, resulting in uneven temperature distribution across the slab's width. This invention addresses this by arranging vertically movable first magnetic conductors along the edges of the slab. By adjusting the movement of these first magnetic conductors according to the target and detection temperatures of each edge region, the heating temperature of each region can be adjusted, making the temperature across the entire width of the slab more uniform. This ensures that the slab remains at the optimal rolling temperature during the final rolling mill cycle. Figure 11 As shown.

[0102] The increased edge temperature after slab heating solves the problem of edge cracking during rolling, eliminating the need for edge trimming and greatly improving product quality and yield. Improved temperature uniformity across the slab width stabilizes the rolling process, ensuring consistent deformation throughout the slab and significantly enhancing product quality and consistency. Furthermore, the stability of the rolling process greatly extends the service life of the rolling equipment.

[0103] The above description only discloses specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or modifications that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An electromagnetic induction heating device, comprising an upper induction head and a lower induction head, wherein both the upper and lower induction heads include a housing and a coil disposed within the housing; characterized in that: Both the upper and lower sensing heads further include a controller, and a first magnetic conductive component, a second magnetic conductive component, and a third magnetic conductive component arranged sequentially along the length of the coil. The first magnetic conductive component and the third magnetic conductive component correspond to the two sides of the blank to be heated, respectively, and the second magnetic conductive component corresponds to the middle of the blank to be heated. Both the first and third magnetic conductive components include a first magnetic conductor that cooperates with the coil and can move up and down, and a driving mechanism that drives the first magnetic conductor to move up and down; the driving mechanism includes a servo hydraulic cylinder, and the piston rod of the servo hydraulic cylinder passes through the housing and is connected to the first magnetic conductor; The second magnetic conductive component includes components that cooperate with and are fixed to the coil. Place A second magnetic conductor is provided on the outer casing; the second magnetic conductor is provided on the outer casing via a connecting assembly, the connecting assembly including an insulating bolt and an insulating block, one end of the insulating bolt is provided on the second magnetic conductor, the other end is provided on the outer casing, and the insulating block is located between the second magnetic conductor and the outer casing and is sleeved on the insulating bolt; The controller is used to control the first magnetic conductor to move up and down through a drive mechanism based on the temperature of the area corresponding to the first magnetic conductor on the slab to be heated and the target temperature, thereby adjusting the gap between the first magnetic conductor and the slab to be heated, and thus adjusting the heating temperature of the area corresponding to the slab to be heated, so as to achieve temperature uniformity in the width direction of the slab.

2. The electromagnetic induction heating device according to claim 1, characterized in that: The number of the first magnetic conductive component and the third magnetic conductive component are equal and there are multiple of each. Each first magnetic conductive component or each third magnetic conductive component corresponds to a region in the width direction of the slab to be heated.

3. The electromagnetic induction heating device according to claim 1, characterized in that: A groove is formed at the bottom of the first and second magnetic conductors to cooperate with the coil, and the long side of the coil passes through the groove of the first and second magnetic conductors.

4. The electromagnetic induction heating device according to claim 3, characterized in that: When each long side cross section of the coil corresponds to a different groove of the first magnetic conductor and / or the second magnetic conductor, the first width is greater than or equal to twice the second width; wherein, the first width refers to the width of the magnetic conductor between two adjacent grooves of the first magnetic conductor and / or the second magnetic conductor, and the second width refers to the width of the outer wall of the magnetic conductor of the outermost groove.

5. The electromagnetic induction heating device according to any one of claims 1 to 4, characterized in that: A first potting layer is provided outside the coil, and a second potting layer is provided on the inner wall of the outer shell. The first potting layer and the second potting layer form an integral whole. A heat-insulating buffer layer is provided between the bottom of the first magnetic conductor and the second potting layer on the bottom surface of the outer shell.

6. A slab production line, characterized in that: The production line is equipped with an electromagnetic induction heating device as described in any one of claims 1 to 5.

7. A control method for the electromagnetic induction heating device as described in any one of claims 1 to 5, characterized in that, The control method includes: Before the slab enters the electromagnetic induction heating equipment, the detection temperature of each region in the width direction of the slab is obtained; Calculate the temperature difference between each region based on the detected temperature and the target temperature of each region along the width of the slab. The movement of the first magnetic conductor corresponding to each region is controlled according to the temperature difference of each region, and the gap between the first magnetic conductor and the slab is adjusted, thereby adjusting the heating temperature of that region and achieving temperature uniformity in the width direction of the slab.

8. The control method for the electromagnetic induction heating device according to claim 7, characterized in that, For the first to N-M electromagnetic induction heating devices, the formula for calculating the target temperature of each region along the width of the slab is as follows: ； in, This represents the target temperature of the i-th region along the width direction of the slab. This indicates the temperature required for slab rolling. The temperature of the i-th region in the width direction of the slab at the entrance of the heating zone is represented by N, the number of electromagnetic induction heating devices is represented by M, and M < N. For the N-M+1th to the Nth electromagnetic induction heating equipment, the formula for calculating the target temperature of each region along the width of the slab is as follows: ； in, This represents the natural heat dissipation temperature drop of the i-th region along the width of the slab from the entrance of the heating zone to the entrance of the rolling zone.

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