Electromagnetic induction heating equipment, control method and slab production line

Abstract

The invention discloses electromagnetic induction heating equipment, a control method and a slab production line, the equipment comprises an upper inductive head and a lower inductive head, the upper inductive head and the lower inductive head each comprise a shell, a coil, a controller, and a first magnetic conductive assembly, a second magnetic conductive assembly and a third magnetic conductive assembly which are sequentially arranged along the length direction of the coil, each of the first magnetic conductive assembly and the third magnetic conductive assembly comprises a first magnetizer matched with the coil and a driving mechanism; the second magnetic conductive assembly comprises a second magnetizer matched with the coil; the controller controls the first magnetizer to move up and down through the driving mechanism according to the area temperature, corresponding to the first magnetizer, on the to-be-heated plate blank and the target temperature, the gap between the first magnetizer and the to-be-heated plate blank is adjusted, then the heating temperature of the area corresponding to the to-be-heated plate blank is adjusted, and temperature uniformity in the width direction of the plate blank is achieved. The heating efficiency of the equipment and the temperature uniformity in the width direction of the plate blank are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of slab heating, and in particular relates to an electromagnetic induction heating device, a control method and a slab production line. Background Art

[0002] In the tide of green transformation of the steel industry, short-process steelmaking is gradually becoming the mainstream trend of industry development with its many advantages such as high efficiency, energy saving and environmental protection. The rise of this trend has not only promoted the innovation of steel production technology, but also brought new opportunities and challenges to the development of related supporting technologies. Among them, the application of induction heating technology in short-process steelmaking is particularly important. The core of short-process steelmaking is to integrate the relatively independent and scattered smelting, casting, heating, rolling and other processes in the traditional steel manufacturing process to achieve continuous production of steel. This change makes the production process more compact and greatly improves production efficiency, but also puts higher requirements on heating technology. With its unique advantages, induction heating technology perfectly meets the needs of short-process steelmaking. It can achieve rapid heating and precise control, and there is no oxidation and decarbonization during the heating process; the heating quality is high, green and environmentally friendly, the energy saving and emission reduction effect is significant, the heating speed is fast, the efficiency is high, the equipment is small, space-saving, and the working conditions can be improved. These advantages have made induction heating technology widely used in short-process steelmaking and become a key technical support for promoting the development of short-process steelmaking.

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

[0004] Firstly, the longitudinal magnetic field heating adopts 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 the slab is heated. Since the closed channel size of the longitudinal magnetic field is fixed, the deformation of the slab can easily damage the sensor. The transverse magnetic field heating includes induction heaters distributed up and down, with no other equipment or components on the left and right. This open channel structure avoids damage to the sensor caused by deformation of the slab (such as warping, deformation, and jumping) during longitudinal magnetic field heating, thereby greatly reducing the risk of equipment damage, reducing the frequency of maintenance, ensuring production continuity, and reducing labor intensity and production costs.

[0005] Secondly, when heating with a longitudinal magnetic field, the induced current on the slab forms a circulation on the surface of the thickness section. On the one hand, this causes the temperature distribution of the slab before and after entering the heater to be similar (the temperature at the edge in the width direction is low, and the temperature in the middle is high), and the temperature non-uniformity still exists. On the other hand, when the thickness of the slab is thin, while ensuring the heating efficiency, higher requirements are put forward for the heating frequency, which also greatly increases the investment cost of the heating equipment. Due to the magnetic field distribution characteristics of transverse magnetic field heating, heat can be more evenly transferred to various parts of the slab during the heating process, achieving more uniform heating of the slab, reducing the performance differences of the slab caused by uneven heating, and improving the stability of product quality; and the requirements for frequency are low, and the equipment investment cost is also greatly reduced.

[0006] In addition, transverse magnetic field heating also facilitates flexible adjustment of the position and arrangement of induction heaters according to different slab specifications and production requirements to achieve the best heating effect and meet the requirements of heating temperature uniformity, providing strong support for the short-process steelmaking to produce steel of different specifications. However, despite the many advantages of transverse magnetic field heating, there are still some problems that need to be solved in the actual process of heating slabs, especially in terms of heating efficiency and temperature uniformity:

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

[0008] (2) Temperature uniformity. 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 cause dimensional deviations and inconsistent performance of the slab during the subsequent rolling process, affecting the quality of the final product.

[0009] In summary, under the trend of short-process steelmaking, the importance of induction heating technology is self-evident, and transverse magnetic field heating plays a key role in short-process steelmaking with its unique advantages. But at the same time, 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] The patent document with publication number CN114981455A provides a transverse magnetic field induction heating device, in which symmetrical upper and lower transverse inductors are arranged on the upper and lower surfaces of the metal strip, respectively. Specifically, the transverse induction coil used is designed as a structure with different shapes at both ends, one end is a trapezoidal semicircle, and by using this unique end shape, the temperature uniformity in the width direction of the plate can be better controlled. However, since the magnetic lines of force generated by the coil all form a loop in the air, the loss is extremely large, and thus the heating efficiency is greatly reduced.

[0011] The patent document with publication number CN111278182A provides an induction heating system and heating method with alternating transverse and longitudinal magnetic fields, which ensures the temperature uniformity of each part of the slab after heating by alternating the arrangement of transverse and longitudinal magnetic fields. However, due to some inherent defects of the longitudinal magnetic field, for example, the equipment may be damaged due to the warping of the slab, and when it is necessary to meet the production of slabs of various specifications, it is difficult for the same set of equipment to achieve good matching and satisfaction. In addition, the combination of longitudinal and transverse magnetic field equipment 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] The patent document with publication number CN117336909A provides a device and method for improving the heating uniformity and heating efficiency of continuous casting and rolling slabs. By arranging magnetic poles in the energized coils, the loss of magnetic field in the air is reduced, and 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 structure of the entire equipment very complicated and large, which brings great inconvenience to on-site operation, control, maintenance and other aspects. In terms of temperature uniformity control, due to the strong magnetic concentration of the magnetic poles, it is extremely difficult to eliminate the temperature difference at the edge, and temperature uniformity is difficult to ensure. Summary of the invention

[0013] The object of the present 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 technical problems through the following technical solutions: an electromagnetic induction heating device, comprising an upper induction head and a lower induction head, wherein the upper induction head and the lower induction head both comprise a shell and a coil disposed in the shell;

[0015] The upper induction head and the lower induction head both further include a controller, and a first magnetic conductive component, a second magnetic conductive component and a third magnetic conductive component sequentially arranged along the length direction of the coil, the first magnetic conductive component and the third magnetic conductive component respectively correspond to the two side edges of the slab to be heated, and the second magnetic conductive component corresponds to the middle part of the slab to be heated; the first magnetic conductive component and the third magnetic conductive component both include a first magnetic conductive body matched with the coil and a driving mechanism for driving the first magnetic conductive body to move; the second magnetic conductive component includes a second magnetic conductive body matched with the coil and arranged on the housing;

[0016] The controller is used to control the movement of the first magnet through a driving mechanism according to the temperature of the area corresponding to the first magnet on the slab to be heated and the target temperature, so as to adjust the gap between the first magnet and the slab to be heated, and then adjust 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 components and the third magnetic conductive components is equal and both are multiple, and each first magnetic conductive component or each third magnetic conductive component corresponds to an area in the width direction of the slab to be heated.

[0018] Furthermore, a groove cooperating with the coil is provided at the bottom of the first magnetic conductor and the second magnetic conductor, and a long side of the coil passes through the grooves of the first magnetic conductor and the second magnetic conductor.

[0019] Further, when each long side cross-section of the coil corresponds to different grooves 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.

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

[0021] Furthermore, the second magnetic conductor is arranged on the outer shell through a connecting component, and the connecting component includes an insulating bolt and an insulating block, one end of the insulating bolt is arranged on the second magnetic conductor, and the other end is arranged on the outer shell, and the insulating block is located between the second magnetic conductor and the outer shell and is 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 shell, and the first potting layer and the second potting layer form a 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 shell.

[0024] Based on the same concept, the present invention provides a slab production line, on which the electromagnetic induction heating device as described above is provided.

[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 area in the width direction of the slab is obtained;

[0027] Calculate the temperature difference of each area according to the detected temperature of each area in the width direction of the slab and the target temperature of each area;

[0028] According to the temperature difference of each area, the movement of the first magnetic conductor corresponding to the area is controlled, the gap between the first magnetic conductor and the slab is adjusted, and then the heating temperature of the area is adjusted to achieve temperature uniformity in the width direction of the slab.

[0029] Furthermore, for the first to the N-M electromagnetic induction heating devices, the target temperature of each area in the slab width direction is calculated as follows:

[0030]

[0031] Among them, T j represents the target temperature of the ith region in the slab width direction, T r Indicates the temperature required for slab rolling, T ej represents the temperature of the ith area in the width direction of the slab at the entrance of the heating zone, N represents the number of electromagnetic induction heating devices, M represents the number of electromagnetic induction heating devices participating in the natural heat dissipation temperature drop compensation, M<N;

[0032] For the N-M+1th to Nth electromagnetic induction heating equipment, the calculation formula for the target temperature of each area in the slab width direction is:

[0033]

[0034] Where, ΔT j It represents the natural heat dissipation temperature drop of the i-th zone in the width direction 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:

[0037] The electromagnetic induction heating equipment of the present invention adopts a combined design of a coil and a magnetizer. The first magnetizers at both ends of the coil in the length direction are movably arranged. The gap between the first magnetizer and the slab is adjusted by adjusting the up and down movement of the first magnetizer through a driving mechanism, thereby adjusting the magnetic flux. 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, thereby achieving uniform temperature control over the entire width direction of the slab, thereby improving product quality and yield rate. At the same time, since the first magnetizer is movably installed, the loss of magnetic lines of force is reduced, the heating efficiency is greatly improved, the utilization rate of electric energy is improved, and the heating cost is reduced.

[0038] The heating temperature can be controlled by adjusting the first magnetic conductors in the upper induction head and the lower induction head, avoiding the overall movement of the upper induction head and the lower induction head, and eliminating the need for mutual misalignment of two adjacent electromagnetic induction heating devices on a production line. The structure is more compact, the control accuracy is higher, and the complexity is lower.

[0039] The first magnetic conductor and the second magnetic conductor are made of soft magnetic composite materials, so that the magnetic field generated by the coil is concentrated in the soft magnetic composite material with high relative magnetic 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 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 is a cross-sectional view of a second magnetic conductive component in an embodiment of the present invention;

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

[0044] Figure 4 Schematic diagram of a rectangular coil formed by a figure-8 winding method in an embodiment of the present invention;

[0045] Figure 5 In the embodiment of the present invention Figure 3The schematic diagram of the cross section of the long side of the rectangular coil shown corresponds to different grooves of the first magnetizer; wherein b represents the width of the first magnetizer between two adjacent grooves, a represents the width of the outer wall of the magnetizer of the outermost groove, e represents the distance between the coil and the first magnetizer, d represents the distance between the groove and the top surface of the first magnetizer, c represents the maximum stroke of the first magnetizer, and h1 represents the margin and is greater than 0;

[0046] Figure 6 In the embodiment of the present invention Figure 3 The cross section of the long side of the rectangular coil shown corresponds to a schematic diagram of the same groove of the first magnetic conductor;

[0047] Figure 7 In the embodiment of the present invention Figure 4 A schematic diagram showing that the cross section of the long side of the rectangular coil corresponds to different grooves of the first magnetic conductor and the outer walls of both sides of the outermost groove are both magnetic conductors;

[0048] Figure 8 In the embodiment of the present invention Figure 4 The schematic diagram of the cross section of the long side of the rectangular coil shown corresponds to different grooves of the first magnetic conductor and one side of the outermost groove has an outer wall of the magnetic conductor and the other side has no outer wall;

[0049] Fig. 9 are magnetic force line paths of different matching forms of the coil and the first magnetic conductor and the second magnetic conductor in the embodiment of the present invention;

[0050] Fig.10 is the temperature curve during the slab conveying process before and after induction heating in the embodiment of the present invention;

[0051] Fig.11 It is the temperature uniformity curve in the width direction of the slab in the embodiment of the present invention.

[0052] Explanation of the accompanying drawings: 100 - upper induction head, 110 - first magnetic conductor, 120 - shell, 121 - second potting layer, 122 - thermal 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 - conveying roller. DETAILED DESCRIPTION

[0053] The following is a clear and complete description of the technical solutions in the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0055] Embodiment 1

[0056] like Figure 1 and Figure 2 As shown, the electromagnetic induction heating equipment provided by the embodiment of the present 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 with the thickness center line of the slab 300 as the symmetry axis. 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. The upper induction head 100 and the lower induction head 200 both include a shell 120, a coil 130 disposed in the shell 120, a controller, and a first magnetic conductive component, a second magnetic conductive component, and a third magnetic conductive component sequentially disposed along the length direction of the coil 130. The first magnetic conductive component and the third magnetic conductive component correspond to the two side edges of the slab, respectively, that is, the induction heating of the two side edges of the slab is achieved through the first magnetic conductive component and the third magnetic conductive component and the coil 130, and the second magnetic conductive component corresponds to the middle part of the slab, that is, the induction heating of the middle part of the slab is achieved through the second magnetic conductive component and the coil 130; the first magnetic conductive component and the third magnetic conductive component are respectively located at both ends of the coil 130 in the length direction and both include a first magnetic conductive body 110 cooperating with the coil 130 and a driving mechanism for driving the first magnetic conductive body 110 to move up and down; the second magnetic conductive component is located in the middle part of the coil 130 in the length direction and includes a second magnetic conductive body 160 cooperating with the coil 130 and disposed on the shell 120.

[0057] The driving mechanism of the first magnetic conductive component and the third magnetic conductive component is electrically connected to the controller. The controller controls the first magnetic conductive body 110 to move up and down through the driving mechanism according to the temperature of the area corresponding to the first magnetic conductive body 110 on the slab to be heated and the target temperature, adjusts the gap between the first magnetic conductive body 110 and the slab to be heated, and then adjusts the heating temperature of the area corresponding to the slab to be heated to achieve temperature uniformity in the width direction of the slab. During the up and down movement of the first magnetic conductive body 110, the first magnetic conductive body 110 does not contact the housing 120 at the upper and lower limit positions.

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

[0059] The regions are divided along the width direction of the slab, the middle region in the width direction of the slab corresponds to the second magnetic conductor 160 of the second magnetic conductor assembly, and the two side regions in the width direction of the slab correspond to the first magnetic conductor assembly and the third magnetic conductor assembly respectively; when there are multiple first magnetic conductor assemblies and multiple third magnetic conductor assemblies, the two side regions are divided into multiple sub-regions, each of which corresponds to a first magnetic conductor 110 of the first magnetic conductor assembly or the third magnetic conductor assembly. The more regions are divided on both sides in the width direction of the slab, the more first magnetic conductors 110 are, the more accurate the heating temperature control of each region is, and the better the temperature uniformity effect in the width direction of the slab is.

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

[0061] In a specific embodiment of the present invention, the first magnetic conductor 110 and the second magnetic conductor 160 are both made of soft magnetic composite materials. The soft magnetic composite materials have good magnetic conductivity and high magnetic saturation. Most importantly, even under medium and high frequency conditions, the induced eddy current is small and the heat generation is minimal, which can greatly simplify the cooling water circuit of the entire heating device. The magnetic conductor of the heating device with this structure does not need water cooling.

[0062] The first magnetizer 110 and the second magnetizer 160 cooperate with the coil 130 in the same manner. In a specific embodiment of the present invention, grooves cooperating with the coil 130 are provided at the bottom of the first magnetizer 110 and the second magnetizer 160, and the long sides of the coil 130 pass through the grooves of the first magnetizer 110 and the second magnetizer 160.

[0063] In this embodiment, the coil 130 is formed by winding a copper tube. The shape of the coil 130 is rectangular. The rectangular coil can reduce the change of the magnetic flux at the transition point of the arc and ensure that the second magnetic conductor 160 and the first magnetic conductor 110 are consistent in appearance. The coil 130 can be formed into a rectangular coil by an O-shaped winding method, such as Figure 3 As shown; the 8-shaped winding method can also be used to form a rectangular coil, such as Figure 4 shown. Figure 4 In the embodiment, the left and right parts of the rectangular coil are connected in series by adopting the figure-8 winding method. After the connection in series, a shielding cover is shared 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] The arrangement of the magnetic conductor on the path of the magnetic force lines generated by the coil 130 will play a role in magnetic concentration. The more magnetic conductors are arranged on the magnetic force line loop, the smaller the magnetic field loss is and the higher the energy utilization rate is. Based on this, there are many ways to match the coil 130 with the first magnetic conductor 110 and the second magnetic conductor 160, such as Figures 5 to 7 shown.

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

[0066] for Figure 5 The matching form of the coil 130, the first magnetic conductor 110 and the second magnetic conductor 160 is shown as follows: Fig. 9 As shown, since there are relatively more magnetic conductors arranged on the path of the magnetic lines of force, the magnetic field loss is relatively small, so the efficiency is relatively higher, but this structural form will result in a relatively small winding space for the coil 130, a small number of turns, and relatively few magnetic lines of force. Figure 6 The matching form of the coil 130, the first magnetic conductor 110 and the second magnetic conductor 160 is shown as follows: Fig. 9 As shown, the winding space of the coil 130 is larger (compared to Figure 5 Compared with the matching form, the number of layers of the coil 130 is the same, but the number of turns of a single layer can be wound more), however, since there is no magnetic conductor in the inner circle of the coil 130, there is an air path in the magnetic field line path, and the magnetic field loss is relatively large.

[0067] for Figure 4 The rectangular coil shown in FIG. 1 has three long sides (the two middle long sides are combined into one) of the coil 130 respectively passing through three different grooves of the first magnetic conductor 110 and the second magnetic conductor 160. The outer walls of the two outermost grooves of the first magnetic conductor 110 and the second magnetic conductor 160 can be both magnetic conductors (such as Figure 7 As shown), one side may be a magnetic conductor and the other side may have no outer wall (as shown Figure 8 shown). Figure 8 In the embodiment, the width of the outermost groove is f, f is greater than or equal to 0, the main path of the magnetic lines of force is in the inner ring of the coil 130, and the outer path is shielded by the shell 120.

[0068] for Figure 7 The matching form of the coil 130, the first magnetic conductor 110 and the second magnetic conductor 160 is shown as follows: Fig. 9 As shown, since there are relatively more magnetic conductors arranged on the path of the magnetic lines of force, the magnetic field loss is relatively small, so the efficiency is relatively higher, but this structural form will result in a relatively small winding space for the coil 130, a small number of turns, and relatively few magnetic lines of force. Figure 8 The matching form of the coil 130, the first magnetic conductor 110 and the second magnetic conductor 160 is shown as follows: Fig. 9 As shown, the winding space of the coil 130 is larger (compared to Figure 7 Compared with the matching form, the number of layers of the coil 130 is the same, but the number of turns of a single layer can be wound more), however, since there is no magnetic conductor in the outer ring of the coil 130, there is an air path in the magnetic field line path, and the magnetic field loss is relatively large.

[0069] When each long side cross section of the coil 130 corresponds to a different groove (such as Figure 5 and Figure 7 ), the first width b is greater than or equal to twice the second width a; wherein the first width b refers to the width of the magnetizer between two adjacent grooves of the first magnetizer 110 and / or the second magnetizer 160, and the second width a refers to the width of the magnetizer outer wall of the outermost groove (i.e., the width of the outer wall with the magnetizer as the outer wall of the groove, and the outer wall is the outermost wall surface). This size restriction ensures that the magnetic lines of force in the middle of the coil 130 all pass through the magnetizer when they are dispersed to both sides, and do not enter the air, thereby reducing the loss of the magnetic field in the air, improving the utilization rate of the magnetic field, and improving the heating efficiency.

[0070] In order to ensure the normal up and down movement of the first magnetic conductor 110, Figure 5 As shown, the distance c+h1 between the bottom surface of the coil 130 and the bottom surface of the first magnetizer 110 is greater than the maximum stroke c of the first magnetizer 110, and the distance c+h2 between the top surface of the first magnetizer 110 and the inner wall of the shell 120 is greater than the maximum stroke c of the first magnetizer 110, wherein h1 and h2 both represent margins and are greater than zero, ensuring that the magnetic lines of force generated by the coil 130 are better concentrated in the magnetizer, reducing the divergence and loss of the magnetic field.

[0071] The number of turns of the coil 130 is greater than or equal to 2, and the number of layers of the coil 130 is greater than or equal to 2. When the coil 130 has multiple turns and multiple layers, Figures 5 to 8 The dimension of the coil 130 to a certain location is the dimension from the side of the coil 130 closest to the location to the location. Figures 5 to 8In the figure, 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 driving mechanism adopts hydraulic drive or electric control drive. When electric control drive is adopted, the driving mechanism includes a driving motor and a linear motion mechanism. The linear motion mechanism is controlled by the driving motor to move linearly, thereby driving the first magnet 110 to move up and down. When hydraulic drive is adopted, the driving 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 magnet 110. The controller is a hydraulic controller 150. In order to ensure the smooth movement of the first magnet 110 in the up and down process, two servo hydraulic cylinders 140 are configured for a single first magnet 110. The two servo hydraulic cylinders 140 are symmetrically arranged about the center line of the first magnet 110, and the two servo hydraulic cylinders 140 are synchronously controlled by the same hydraulic controller 150, ensuring that the first magnet 110 is not blocked in the up and down movement process.

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

[0074] In a specific embodiment of the present invention, the second magnetic conductor 160 is disposed on the housing 120 through a connecting assembly. Figure 2 As shown, the connection 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 housing 120. The insulating block 162 is located between the second magnetic conductor 160 and the housing 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 is not in direct contact with the housing 120.

[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 housing 120 . The first potting layer 131 and the second potting layer 121 form a whole.

[0076] After the coil 130 is prefabricated, it forms a whole with the first potting layer 131. After the whole is assembled with the first magnet 110 and the second magnet 160, the coil 130 is located in the groove of the first magnet 110 and the second magnet 160. The first potting layer 131 wraps the coil 130 and maintains a certain thickness, which ensures the insulation between the coil 130 and the first magnet 110 and the second magnet 160. The thickness of the first potting layer 131 is related to the working voltage of the electromagnetic induction heating device. The higher the working voltage, the greater the thickness of the first potting layer 131. At the same time, the thickness of the first potting layer 131 close to the first magnet 110 and the second magnet 160 is smaller than the distance e between the coil 130 and the first magnet 110 and the second magnet 160, ensuring the smooth up and down movement of the first magnet 110.

[0077] The second potting layer 121 is arranged on the bottom and side of the housing 120, and forms a whole with the first potting layer 131. In order to ensure the integrity of the potting layer and the housing 120, the second potting layer 121 and the housing 120 can be connected by anchoring nails to bear the overall weight of the coil 130 and the first potting layer 131 and the second potting layer 121. The first potting layer 131 and the second potting layer 121 have 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 housing 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 magnetizer 110 and the second potting layer 121 on the bottom surface of the housing 120. The heat insulating buffer layer 122 is resistant to high temperatures, and not only isolates the heat radiation of the heated slab, but also prevents the first magnetizer 110 and the second potting layer 121 from direct contact, collision and damage.

[0079] The slab production line provided by the embodiment of the present invention is provided with the electromagnetic induction heating device according to the embodiment of the present invention. A plurality of electromagnetic induction heating devices are arranged along the conveying direction of the slabs. 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 identical, thereby ensuring interchangeability.

[0080] Embodiment 2

[0081] The continuous casting slab is constantly dissipating heat during the casting and conveying process. The heat dissipation rate at the corners of the slab is greater than that at the center of the slab in the width direction. Before reaching the induction heating zone, the temperature of the slab in the width direction is low at the edge and high at the center. The temperature curve is as follows: Fig.10The temperature of the AB section on the left side of the slab width direction and the CD section on the right side of the slab width direction are symmetrical, and due to the different continuous casting processes and the different specifications of the slabs produced, the high and low temperature differences between the AB section and the CD section are also different.

[0082] Before the slab enters the induction heater, even if the temperature in the width direction is the same, after being heated by an induction heater (without a movable magnetic conductor), the temperature of the slab will be high at both sides of the slab width direction, while the temperature near the edge (towards the center) will be low. Fig.10 As shown in the right figure. This is because the inner coil length (excluding the gap between each turn and the gap between turns) of the coil is slightly larger than the width of the slab, resulting in an edge effect, which causes the edge temperature to be higher than the middle temperature by △T1. Under the same heating power, and due to the different slab thicknesses, the edge temperature is also different. The thinner the slab, the higher the edge overheating temperature.

[0083] In actual situations, when the slab enters the induction heater, the temperature of the edge of the slab is actually too low. After passing through the induction heater, the overall temperature of the slab increases (for example, the temperature of the middle of the slab increases by △T2). The excessive temperature rise of the edge will compensate for the low temperature of the incoming material, and when passing through multiple sets of induction heaters, the temperature of the edge will exceed the temperature of the middle. In addition, since there is a low temperature area near the center of the edge, the temperature in the entire width direction will be uneven.

[0084] If the inner turn length of the coil is slightly smaller than the width of the slab, there will be no edge effect, and the edge temperature in the width direction of the slab will not exceed the middle temperature. However, there will still be a low temperature zone near the center of the edge, which will also cause uneven temperature in the entire width direction.

[0085] In order to solve the above technical problems, the present invention provides a control method for electromagnetic induction heating equipment, which is applied to the electromagnetic induction heating equipment in the first embodiment of the present invention, wherein a first magnetic conductor that can move up and down is arranged at both ends of the coil in the length direction, and a fixed second magnetic conductor is arranged in the middle of the coil in the length direction, 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, and the induction heating of the edge of the slab is achieved by the cooperation of the first magnetic conductor and the coil, and the induction heating of the edge of the slab is achieved by the cooperation of the second magnetic conductor and the coil. Since the first magnetic conductor can move up and down, the gap between the first magnetic conductor and the slab can be adjusted by controlling the up and down movement of the first magnetic conductor, thereby adjusting the heating temperature or heating rate of the edge of the slab, and achieving temperature uniformity in the width direction of the slab.

[0086] like Fig.10As shown in the right figure, when the length of the magnetic conductor arranged along the length direction of the coil is greater than the width of the slab, an edge effect will occur, causing the temperature at the edge to be higher than the temperature in the middle, and a low temperature zone will appear at the edge near the middle; when the length of the magnetic conductor arranged along the length direction 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 at the edge near the middle still exists. Therefore, multiple first magnetic conductor components (corresponding to Fig.10 L1 width in the right figure) and multiple second magnetic conductive components (corresponding to Fig.10 L2 width in the right figure), the first magnetic conductor of each first magnetic conductive component or the first magnetic conductive body of the second magnetic conductive component corresponds to an area on the edge of the slab in the width direction, so as to achieve individual adjustment of the heating temperature of the area, thereby achieving temperature uniformity in the entire width direction of the slab.

[0087] The control method comprises the following steps:

[0088] Step S1: before the slab enters the electromagnetic induction heating equipment, the detected temperature of each area in the width direction of the slab is obtained;

[0089] Step S2: calculating the temperature difference of each area according to the detected temperature of each area in the width direction of the slab and the target temperature of each area;

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

[0091] In step S1, a scanning thermometer is used to detect the temperature of the entire width direction of the slab, that is, to obtain the detected temperature of each area in the width direction of the slab. When the detected temperature of each area is lower than its target temperature, the first magnetizer of the area is controlled to move downward, the gap between the first magnetizer and the slab is reduced, and the magnetic flux of the area is increased, thereby increasing the induced current of the area, increasing the heating temperature of the area, and increasing the temperature rise rate of the area; when the detected temperature of each area is higher than its target temperature, the first magnetizer of the area is controlled to move upward, the gap between the first magnetizer and the slab is increased, and the magnetic flux of the area is reduced, thereby reducing the induced current of the area, reducing the heating temperature of the area, and reducing the temperature rise rate of the area.

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

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

[0094] There is a certain distance between the heating zone and the rolling zone. There is still heat exchange during the transfer of the slab from the heating zone to the rolling zone. The heat exchange over this distance will still cause uneven temperature with low temperature at the edge and high temperature in the middle of the slab. Therefore, it is necessary to compensate for the natural heat dissipation temperature drop during induction heating. The higher the temperature of the slab, the faster the heat dissipation rate and the more electricity is consumed. In order to reduce energy consumption while achieving natural heat dissipation temperature drop compensation, the first N-M electromagnetic induction heating devices do not participate in the natural heat dissipation temperature drop compensation, and the last M electromagnetic induction heating devices are used to participate in the natural heat dissipation temperature drop compensation.

[0095] For the 1st to N-Mth electromagnetic induction heating equipment, the calculation formula for the target temperature of each area in the slab width direction is:

[0096]

[0097] Among them, T j represents the target temperature of the ith region in the slab width direction, T r Indicates the temperature required for slab rolling, T ej represents the temperature of the i-th area 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 natural heat dissipation temperature drop compensation.

[0098] For the N-M+1th to Nth electromagnetic induction heating equipment, the calculation formula for the target temperature of each area in the slab width direction is:

[0099]

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

[0101] Since the edge of the slab dissipates heat quickly, the final compensation temperature of the edge of the slab is higher than that of the middle of the slab, resulting in uneven temperature in the width direction of the slab. The present invention arranges a first magnetic conductor that can move up and down corresponding to the edge of the slab, and adjusts the movement of the first magnetic conductor corresponding to each area according to the target temperature and detection temperature of each area of ​​the edge, so as to adjust the heating temperature of each area, so that the temperature of the entire width direction of the slab tends to be consistent, thereby making the slab still at the optimal rolling temperature when rolling in the last group of rolling mills, such as Fig.11 shown.

[0102] The increase in edge temperature after slab heating solves the problem of edge cracking during the rolling process, eliminating the trimming process and greatly improving product quality and yield rate. The improvement in temperature uniformity in the width direction of the slab stabilizes the rolling process, and the deformation of the slab at various locations tends to be consistent when it is rolled, greatly improving product quality and consistency. The stability of the rolling process also greatly increases the service life of the rolling equipment.

[0103] What is disclosed above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or modifications within the technical scope disclosed in the present invention, which should be included in the protection scope of the present invention.

Claims

1. An electromagnetic induction heating device, comprising an upper induction head and a lower induction head, wherein the upper induction head and the lower induction head each comprise a housing and a coil disposed in the housing; characterized in that: The upper induction head and the lower induction head both further include a controller, and a first magnetic conductive component, a second magnetic conductive component and a third magnetic conductive component sequentially arranged along the length direction of the coil, the first magnetic conductive component and the third magnetic conductive component respectively correspond to the two side edges of the slab to be heated, and the second magnetic conductive component corresponds to the middle part of the slab to be heated; the first magnetic conductive component and the third magnetic conductive component both include a first magnetic conductive body matched with the coil and a driving mechanism for driving the first magnetic conductive body to move; the second magnetic conductive component includes a second magnetic conductive body matched with the coil and arranged on the housing; The controller is used to control the movement of the first magnet through a driving mechanism according to the temperature of the area corresponding to the first magnet on the slab to be heated and the target temperature, so as to adjust the gap between the first magnet and the slab to be heated, and then adjust 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 components and the third magnetic conductive components are equal and both are multiple, and each first magnetic conductive component or each third magnetic conductive component corresponds to an area 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 matching with the coil is provided at the bottom of the first magnetic conductor and the second magnetic conductor, and the long side of the coil passes through the grooves of the first magnetic conductor and the second magnetic conductor.

4. The electromagnetic induction heating device according to claim 3, characterized in that: When each long side cross-section of the coil corresponds to different grooves 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 magnetic conductor outer wall of the outermost groove.

5. The electromagnetic induction heating device according to claim 1, characterized in that: The driving mechanism comprises a servo hydraulic cylinder, a piston rod of which passes through a housing and is connected to the first magnetic conductor.

6. The electromagnetic induction heating device according to claim 1, characterized in that: The second magnetic conductor is arranged on the outer shell through a connecting component, and the connecting component includes an insulating bolt and an insulating block. One end of the insulating bolt is arranged on the second magnetic conductor, and the other end is arranged on the outer shell. The insulating block is located between the second magnetic conductor and the outer shell and is sleeved on the insulating bolt.

7. The electromagnetic induction heating device according to any one of claims 1 to 6, 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 shell, wherein the first potting layer and the second potting layer form a whole; 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 shell.

8. A slab production line, characterized in that: The production line is provided with the electromagnetic induction heating device according to any one of claims 1 to 7.

9. A control method for the electromagnetic induction heating device according to any one of claims 1 to 7, characterized in that: The control method comprises: Before the slab enters the electromagnetic induction heating equipment, the detection temperature of each area in the width direction of the slab is obtained; Calculate the temperature difference of each area according to the detected temperature of each area in the width direction of the slab and the target temperature of each area; According to the temperature difference of each area, the movement of the first magnetic conductor corresponding to the area is controlled, the gap between the first magnetic conductor and the slab is adjusted, and then the heating temperature of the area is adjusted to achieve temperature uniformity in the width direction of the slab.

10. The control method of the electromagnetic induction heating device according to claim 9, characterized in that: For the 1st to N-Mth electromagnetic induction heating equipment, the calculation formula for the target temperature of each area in the slab width direction is: Among them, T j represents the target temperature of the ith region in the slab width direction, T r Indicates the temperature required for slab rolling, T ej represents the temperature of the ith area in the width direction of the slab at the entrance of the heating zone, N represents the number of electromagnetic induction heating devices, M represents the number of electromagnetic induction heating devices participating in the natural heat dissipation temperature drop compensation, M<N; For the N-M+1th to Nth electromagnetic induction heating equipment, the calculation formula for the target temperature of each area in the slab width direction is: Where, ΔT j It represents the natural heat dissipation temperature drop of the i-th zone in the width direction of the slab from the entrance of the heating zone to the entrance of the rolling zone.

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