An induction heating tundish for continuous casting of steel and its control method

Abstract

The present invention relates to the technical field of induction heating of continuous casting tundishes, in particular to a steel continuous casting induction heating tundish and its control method, which includes a receiving chamber and a pouring chamber. The receiving chamber and the pouring chamber are connected by at least two induction heating channels. At least one induction heating device is arranged in the induction heating channel. The induction heating device includes a closed-loop iron core and at least two coils wound around the closed-loop iron core in combination. The combined winding mode of the coils is such that the axes of at least two coils are perpendicular to each other, aiming to solve the technical problems in the prior art that the induction heating equipment of the tundish causes erosion of the bottom refractory material at the channel outlet, easily increases the amount of inclusions in the molten steel, and shortens the service life of the tundish.

Description

Technical Field

[0001] The present invention relates to the technical field of continuous casting tundish induction heating, in particular to a steel continuous casting induction heating tundish and its control method. Background Art

[0002] As a metallurgical container connecting the upstream and downstream in the metallurgical continuous casting process, the traditional functions of the tundish are flow diversion, pressure reduction, continuous casting, and protection. With the progress of continuous casting technology, the metallurgical functions of the tundish are not only limited to being a traditional molten steel container, but further require the tundish to achieve metallurgical functions such as heat preservation, refining, inclusion removal, and precise temperature control. The stable temperature of the molten steel in the tundish is the premise for realizing the continuous casting constant temperature and constant casting speed process. However, during the casting process, there is inevitably a certain degree of heat loss between the ladle and the tundish, and the temperature continuously decreases as the casting progresses. In order to compensate for the heat loss of the molten steel, the currently mainly applied tundish heating technology in China is the channel type electromagnetic induction heating technology.

[0003] The principle of the channel type electromagnetic induction heating tundish is that after a single-phase power frequency alternating current is applied to the coil of the induction heating device, an alternating magnetic flux will be generated in the molten steel forming a closed conductive loop, further generating an induced current inside the molten steel, and then generating Joule heat to promote the temperature rise of the molten steel. The non-contact electromagnetic induction tundish heating technology can not only effectively compensate for the temperature drop of the molten steel in the tundish, but also has a certain refining and purification function, which can effectively reduce the amount of non-metallic inclusions and oxygen content. In the general form of the channel type induction heating tundish, the channel is buried at the bottom of the tundish. In recent years' research and applications, it has been found that the electromagnetic force will change the flow form of the molten steel. Under the application of conventional induction heating equipment, burying the channel at the bottom of the tundish will cause the molten steel at the channel outlet to have a downward flow and scour the refractory material at the bottom of the tundish, which will not only increase the amount of exogenous inclusions in the molten steel, be unfavorable for improving the cleanliness of the molten steel, but also affect the service life of the tundish and increase production costs. Summary of the Invention

[0004] The purpose of the present invention is to provide a steel continuous casting induction heating tundish and its control method, which are used to solve the technical problems in the prior art that the induction heating equipment of the tundish causes the channel outlet to scour the refractory material at the bottom, easily increases the amount of inclusions in the molten steel, and shortens the service life of the tundish.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A steel continuous casting induction heating tundish includes a receiving chamber and a pouring chamber. The receiving chamber and the pouring chamber are connected by at least two induction heating channels. At least one induction heating device is arranged in the induction heating channel. The induction heating device includes a closed-loop iron core and at least two coils wound around the closed-loop iron core in combination.

[0007] Further, the combined winding method of the coils is such that the axes of at least two coils are perpendicular to each other.

[0008] Further, the number of the induction heating channels is two, and an induction heating device is arranged on each induction heating channel.

[0009] Further, the coil includes a first coil horizontally wound around a closed-loop iron core and a second coil vertically wound around the closed-loop iron core, and the total number of turns of the two coils is higher than the number of turns of the coil required for the induction heating device to operate at the highest load.

[0010] Further, the currents accessed by the coils are in the same direction, have the same magnitude, and are connected to the same power supply.

[0011] Further, the number of turns of the first coil accessed is greater than the number of turns of the second coil accessed, and the number of turns of the first coil accessed is not less than λ1 times the number of turns of the second coil accessed, where λ1 ranges from 1.4 to 1.5.

[0012] Further, the ratio of the number of turns of the first coil (42) accessed to the number of turns of the second coil (43) accessed is determined by the ratio of the thermal buoyancy F b to the inertial force F i , that is, as follows:

[0013]

[0014] where λ1 ranges from 1.1 to 1.2, λ2 ranges from 0.6 to 0.7, N1 and N2 are the number of turns of the first coil (42) accessed and the number of turns of the second coil (43) accessed respectively; where the number of turns of N2 is not less than 100 turns; where generally ranges between 0.2 and 0.5, if is less than 0.2 or greater than 0.5, then the number of turns is set according to the value at 0.2 or 0.5, that is, when is less than 0.2, then the number of turns is set to 0.2; when is greater than 0.5, then the number of turns is set to 0.5.

[0015] Further, the ratio of the thermal buoyancy to the inertial force is as follows:

[0016]

[0017] where β is the coefficient of thermal expansion of the molten steel, g is the acceleration due to gravity, ΔT is the temperature difference between the incoming flow of the molten steel and the molten steel already existing in the tundish, u is the characteristic flow velocity of the molten steel in the tundish, and l is the characteristic length of the tundish;

[0018] where the calculation method of the characteristic length l of the tundish is:

[0019]

[0020] In the above formula, h is the vertical distance between the outlet of the induction heating channel and the outlet of the pouring chamber in the pouring chamber.

[0021] Among them, the characteristic flow velocity of the molten steel in the tundish is calculated by the following formula:

[0022]

[0023] Among them, n is the number of outlets of the pouring chamber, S is the cross-sectional area of the continuous casting billet, v is the drawing speed of the continuous casting billet, ρ1 is the density of the continuous casting billet, m is the number of induction heating channels, D is the inner diameter of the induction heating channel, and ρ2 is the density of the molten steel.

[0024] A control method for an induction heating tundish for continuous casting of steel, adopting the above-mentioned induction heating tundish, includes the following steps:

[0025] S1: At the initial stage of molten steel pouring or when the superheat is high, the induction heating device does not need to be turned on. When the molten steel temperature is lower than the set threshold value, the induction heating device is turned on;

[0026] S2: Determine the specific values of N1 and N2 through formula (1), and connect the number of turns of the first coil (42) and the second coil (43) according to the specific values of N1 and N2;

[0027] S3: Connect the power supply to make the first coil (42) and the second coil (43) energized. By setting the ratio of the number of turns of the first coil (42) and the second coil (43), the electromagnetic force that is large at the top and small at the bottom in the induction heating channel (3) is adjusted to the electromagnetic force that is small at the top and large at the bottom, and then the flow form of the molten steel at the outlet of the induction heating channel (3) is adjusted from the downward flow to the upward flow;

[0028] S4: At the end of pouring, when the molten steel is lower than the induction heating channel (3), turn off the induction heating device.

[0029] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0030] (1). Without changing the structure of the tundish body, by setting an induction heating device, the alternating magnetic flux generated after the coil is energized generates Joule heat, thereby increasing the temperature of the molten steel in the induction heating channel, and further realizing the compensation for the temperature drop of the molten steel;

[0031] (2) Without changing the structure of the tundish body, by setting up an induction heating device, while ensuring the heating efficiency, by setting a horizontally wound first coil, a vertically wound second coil, and regulating the access turn ratio of the combined coils, the electromagnetic force that is larger at the top and smaller at the bottom in the induction heating channel is regulated to be smaller at the top and larger at the bottom. Specifically, the first coil is horizontally wound, and its heating efficiency is lower than that of the vertically wound second coil, but the magnetic field it generates can adjust the flow pattern of the molten steel in the induction heating channel. The second coil is vertically wound. In addition to cooperating with the first coil to heat the molten steel in the induction heating channel, it also works together with the first coil to adjust the flow pattern of the molten steel in the induction heating channel. The magnetic field generated by the synergistic effect of the two can change the electromagnetic force in the induction heating channel, thereby changing the flow form of the molten steel at the outlet of the induction heating channel. By setting the turn ratio of the access between the first coil and the second coil, the downward flow that is common when the molten steel flows out in the prior art is adjusted to an upward flow, prolonging the residence time of the molten steel, avoiding the erosion of the working layer refractory at the bottom of the receiving chamber of the tundish when the molten steel flows out, thereby reducing production costs, and at the same time increasing the probability of inclusion floating up and removal, improving the cleanliness of the molten steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic structural diagram of the continuous casting induction heating tundish of the present invention;

[0033] Figure 2 is a schematic structural diagram of the induction heating device with a combined coil of the present invention;

[0034] Figure 3 is a schematic diagram of the electromagnetic force in the channel when only the second coil is turned on;

[0035] Figure 4 is a schematic diagram of the electromagnetic force in the channel when the combined coil of the present invention is used;

[0036] Figure 5 is a schematic diagram of the flow direction of the molten steel at the outlet of the channel when only the second coil is turned on;

[0037] Figure 6 is a schematic diagram of the flow direction of the molten steel at the outlet of the channel when the combined coil of the present invention is used.

[0038] In the figure, 1, receiving chamber; 2, pouring chamber; 21, pouring chamber outlet; 3, induction heating channel; 4, induction heating device; 41, iron core; 42, first coil; 43, second coil. DETAILED DESCRIPTION OF THE INVENTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] The accompanying drawings are only for illustrative purposes and cannot be construed as a limitation of this patent;

[0041] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0042] When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0043] In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0044] In addition, in the description of the present application, unless otherwise specified, "a plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after. The following further elaborates on the present invention with reference to the accompanying drawings and embodiments.

[0045] To solve the limitations of the prior art, this embodiment provides a technical solution. The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0046] The present invention provides a steel continuous casting induction heating tundish. See the attached Figure 1, including a receiving chamber 1 for receiving incoming molten steel and a pouring chamber 2 for pouring molten steel. The receiving chamber 1 and the pouring chamber 2 are connected by at least two induction heating channels 3. During pouring, the molten steel flows from the pouring chamber 2 into the receiving chamber 1 through the induction heating channels 3. The number of induction heating channels 3 can be two or more. The connection point of the induction heating channel 3 and the receiving chamber 1 is located at the lower part of the receiving chamber 1. The induction heating channel 3 is used to connect the receiving chamber 1 and the pouring chamber 2 and serves as the main area for heating the molten steel. Specifically, at least one induction heating device 4 is provided in the induction heating channel 3. The induction heating device 4 includes at least one closed-loop iron core 41 and at least two coils wound around the closed-loop iron core 41 in combination. The shape of the iron core 41 can be square, circular or other shapes. The combined winding method of the coils is that the axes of at least two coils are perpendicular to each other. See attached Figure 2 , specifically, the coil includes a first coil 42 horizontally wound around the closed-loop iron core 41 and a second coil 43 vertically wound around the closed-loop iron core 41. That is, the axis of the wound first coil 42 is in the horizontal direction, and the axis of the wound second coil 43 is in the vertical direction. The total number of turns of the two coils is higher than the number of turns of the coil required for the induction heating device 4 to operate at the highest load. The first coil 42 and the second coil 43 are connected in series and have the same winding direction. The current connected to the coils is in the same direction, with the same magnitude and is connected to the same power supply.

[0047] It should be noted that when multiple induction heating devices 4 are provided, the currents connected to the coils of adjacent two induction heating devices are in the opposite direction. Through the above settings, the leakage magnetic field of adjacent induction heating devices can be utilized to the greatest extent. Secondly, there are two induction heating devices. The second coils 43 of the two induction heating devices 4 are arranged adjacent to each other. The vertically arranged second coil mainly plays the function of electromagnetic induction heating. Arranging the second coils 43 of the two electromagnetic induction heating devices 4 adjacent to each other can greatly improve the synergistic effect between the induction heating devices 4 and comprehensively utilize the leakage magnetic field.

[0048] The number of turns of the first coil 42 connected is greater than the number of turns of the second coil 43 connected. Here, the number of turns connected is the number of turns of the coil selected for actual power-on operation. The ratio of the number of turns of the first coil 42 connected to the number of turns of the second coil 43 connected is determined by the ratio of the thermal buoyancy F b and the inertial force F i , that is, as follows:

[0049]

[0050] Among them, the value of λ1 ranges from 1.1 to 1.2, the value of λ2 ranges from 0.6 to 0.7, and N1 and N2 are the number of turns of the first coil 42 connected and the number of turns of the second coil 43 connected respectively. Among them, the number of turns of N1 is not less than 100 turns. Among them generally ranges between 0.2 and 0.5. If If the value is less than 0.2 or greater than 0.5, the number of turns is set based on the value at 0.2 or 0.5. That is, when the value is less than 0.2, the number of turns is set to 0.2; when the value is greater than 0.5, the number of turns is set to 0.5.

[0051] After calculating the ratio of N1 and N2 through the above formula, calculate N2 turns based on the value of N1 turns. It should be noted that when the N2 value calculated through the above formula has a decimal place, the rounding algorithm or the rounding method can be used for rounding. Since the difference in the number of turns between the rounding algorithm and the rounding algorithm is one or two turns, it will not have a great impact on the synergistic effect. For example, the value of 100.5 is rounded to 100 and rounded to 101 after rounding.

[0052] The ratio of the thermal buoyancy and the inertial force is as follows:

[0053]

[0054] Among them, β is the coefficient of thermal expansion of the molten steel, g is the acceleration due to gravity, ΔT is the temperature difference between the incoming molten steel and the molten steel already existing in the tundish, u is the characteristic flow velocity of the molten steel in the tundish, and l is the characteristic length of the tundish.

[0055] Among them, the calculation method of the characteristic length l of the tundish is:

[0056]

[0057] In the above formula, h is the vertical distance between the outlet of the induction heating channel and the outlet of the pouring chamber in the pouring chamber. When there are no ribs or dams in the pouring chamber, that is, a trough-shaped pouring chamber formed by five planes is used. Secondly, in order to better apply the theory proposed in this application, a creative design is made for the characteristic length l of the tundish in this application. Specifically, for those with ribs or dams, when the number in the embodiments of the present invention does not exceed 3, the value of h is corrected.

[0058] Among them, the characteristic flow velocity u of the molten steel in the tundish is calculated by the following formula:

[0059]

[0060] Among them, n is the number of outlets 21 of the pouring chamber, S is the cross-sectional area of the billet, v is the casting speed of the billet, ρ1 is the density of the billet, m is the number of induction heating channels, D is the inner diameter of the induction heating channel, and ρ2 is the density of the molten steel.

[0061] The heating efficiency of the vertically arranged second coil 43 is high, but it will cause the magnetic induction intensity B distribution on the wall of the pouring zone to be small at the upper and lower parts, resulting in the electromagnetic force at the outlet of the channel being downward. While the horizontally placed first coil 42 can make the magnetic induction intensity B at the lower part of the wall of the pouring zone large and the upper part small, and then the electromagnetic force is upward. However, the utilization rate of electromagnetic induction heating when placed horizontally is slightly lower. The wall of the pouring zone is located at the outlet of the induction heating channel 3 in the pouring chamber 2. Therefore, combining the effects of both, an upward electromagnetic force is required, and at the same time, the low heating efficiency can be alleviated. But at the same time, there will be corresponding technical problems, that is, how to set the first coil 42 and the second coil 43 so that the flow field and heating efficiency in the pouring zone meet the design requirements. The magnetic fields generated by the two coils have a synergistic relationship and are not simply superimposed. For the above reasons, the present invention proposes the above control formula to meet the requirements of the pouring process for the flow field.

[0062] When the number of induction heating channels 3 is two and both are provided with induction heating devices, there is a problem of mutual influence between the induction heating devices, resulting in a decrease in the power utilization rate of the electromagnetic induction heating device. Based on the above problems, the present invention proposes a corresponding setting method to reduce the influence between the two electromagnetic induction heating devices and improve the power utilization rate of the two electromagnetic induction heating devices.

[0063]

[0064] In the formula, α is the opening angle of the receiving chamber 1 facing the two induction heating channels 3 in the pouring chamber 2, λ3 is the correction coefficient, which takes a value of 3.1 - 3.9 in the embodiment of the present invention, D is the inner diameter of the induction heating channel, r is the wall thickness of the induction heating channel, L is the length of the induction heating channel, s is the distance between the induction heating devices 4 on the two induction heating channels, P1 is the power applied by one induction heating device, P2 is the power applied by the other induction heating device, and P0 is the standard applied power, and its value can be selected according to the specific steel type and process. In the embodiment of the present invention, it takes a value of 4 - 6 kw.

[0065] The present invention also discloses a control method for an induction heating tundish for continuous casting of steel, including the following steps:

[0066] S1: In the initial stage of steel pouring or when the superheat is high, the induction heating device 4 does not need to be turned on. When the temperature of the molten steel is lower than the set threshold, the induction heating device 4 is turned on.

[0067] It should be noted that the set threshold here is set by technicians according to the steel type and pouring process requirements.

[0068] S2: Determine the specific values of N1 and N2 through formula (1), and connect the number of turns of the first coil 42 and the second coil 43 according to the specific values of N1 and N2.

[0069] S3: Turn on the power supply to energize the first coil 42 and the second coil 43. By setting the ratio of the first coil 42 and the second coil 43 and the ratio of the number of turns of the first coil 42 and the second coil 43 connected, under the combined synergistic effect of the combined coil, the electromagnetic force that is large at the top and small at the bottom in the induction heating channel 3 is regulated into an electromagnetic force that is small at the top and large at the bottom, and then the flow form of the molten steel at the outlet of the induction heating channel 3 is adjusted from a downward flow to an upward flow.

[0070] S4: At the end of pouring, when the molten steel is lower than the induction heating channel 3, turn off the induction heating device.

[0071] Examples 1 - 4

[0072] A continuous casting induction heating tundish for steel, comprising a receiving chamber 1 and a pouring chamber 2. The receiving chamber 1 and the pouring chamber 2 are connected by two induction heating channels 3. An induction heating device 4 is provided on each induction heating channel 3. The induction heating device 4 includes a closed-loop iron core 41 and two coils. The two coils are respectively the first coil 42 horizontally wound around the iron core 41 and the second coil 43 vertically wound around the iron core 41. The differences in Examples 1 - 4 are as follows: In Examples 1 - 7, the respective parameter data are collected to calculate the thermal buoyancy F b and the inertial force F i ratio. According to formula (1), the ratio of the number of turns N1 of the first coil 42 connected to the number of turns N2 of the second coil 43 connected is determined, and then the number of turns N1 of the first coil 42 connected and the number of turns N2 of the second coil 43 connected are obtained.

[0073] In Examples 1 - 4, the value of λ1 is 1.2 and the value of λ2 is 0.6

[0074] Comparative Example 1

[0075] The difference from Example 1 is that Comparative Example 1 only sets the first coil 42 and the number of turns connected is the same as that of the first coil 42 in Example 1, and the power applied to the first coil 42 is the same as that in Example 1.

[0076] Comparative Example 2

[0077] The difference from Example 1 is that Comparative Example 2 only sets the second coil 43 and the number of turns connected is the same as that of the first coil 43 in Example 1, and the power applied to the second coil 43 is the same as that in Example 1.

[0078] Comparative Example 3

[0079] The difference from Example 1 is that in Comparative Example 3, the number of turns N2 of the second coil 43 is set to 25, and the power applied is the same as that in Example 1.

[0080] Comparative Example 4

[0081] The difference from Example 1 is that in Comparative Example 4, the number of turns N2 of the second coil 43 is set to 40, and the applied power is the same as that in Example 1.

[0082] Test the heating efficiency, flow field in the pouring area, and inclusion removal rate of Examples 1-4 and Comparative Examples 1-4. The basis for the inclusion removal rate is obtained by observing the number of inclusions in a 20X20μm area when the first coil 42 and the second coil 43 are not set. The data is shown in Table 1.

[0083] Table 1 Test results of Examples 1-4 and Comparative Examples 1-4

[0084]

[0085] It should be noted that the upward flow is the flow direction of the molten steel after flowing through the induction heating channel 3. When the flow direction is upward and the angle is greater than 5°, it is an upward flow; when the flow direction is downward and the angle is greater than 5°, it is a downward flow; when the flow direction is between ±5°, it is a horizontal flow.

[0086] From the comparison of the detection data of the above Examples 1-4, it can be seen that when Examples 1-4 all adopt the combined coil, by using the formula (1) disclosed in the technical solution of the present invention to determine and set the proportion of the number of turns of the combined coil connected, while ensuring the heating efficiency, the flow field in the pouring area is controlled and the cleanliness of the molten steel is improved, increasing the probability of floating and removing inclusions.

[0087] From the comparison of the detection data of the above Example 1 and Comparative Examples 1-4, it can be seen that when only the first coil 42 is used in Comparative Example 1, an upward flow can be generated, but the heating effect on the molten steel is greatly weakened, resulting in a significantly lower inclusion removal rate; in Comparative Example 2, only the second coil 43 is used, which can increase the superheat of the molten steel and the heating efficiency is relatively high, but due to the generation of a downward flow, the inclusion removal rate decreases significantly; in Comparative Example 3, since the number of turns of the second coil 43 is set less, the superheat of the molten steel is reduced, making the inclusion removal rate smaller than that of Examples 1-4; in Comparative Example 4, due to the generation of a horizontal flow, the inclusion removal rate is reduced to a certain extent.

[0088] From the above examples and comparative examples, it can be seen that without changing the structure of the tundish body, by adopting the technical solution of the present invention, the temperature of the molten steel in the induction heating channel can still be increased, thereby realizing the compensation for the temperature drop of the molten steel. At the same time, while ensuring the heating efficiency, by adjusting the proportion of the combined coil, the flow form of the molten steel at the outlet of the induction heating channel is changed. The magnetic field generated by the synergistic effect of the combined coil can change the electromagnetic force in the induction heating channel. See the appendix Figure 3 and 4 Comparing, it can be seen that the molten steel is adjusted from a downward flow to an upward flow. See the appendixFigure 5 and 6 It can be seen that by extending the residence time of the molten steel, the erosion of the refractory material of the working layer at the bottom of the tundish by the molten steel can be avoided, the production cost can be reduced, and at the same time, the probability of inclusion floating up and removal can be increased, and the cleanliness of the molten steel can be improved.

[0089] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0090] The foregoing is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A steel continuous casting induction heating tundish, characterized in that It includes a receiving chamber (1) and a pouring chamber (2), and the receiving chamber (1) and the pouring chamber (2) are connected by at least two induction heating channels (3). At least one induction heating device (4) is provided in the induction heating channel (3). The induction heating device (4) includes a closed-loop iron core (41) and at least two coils wound around the closed-loop iron core (41) in combination; The coils include a first coil (42) horizontally wound around the closed-loop iron core (41) and a second coil (43) vertically wound around the closed-loop iron core (41). The total number of turns of the two coils is higher than the number of turns of the coil required for the induction heating device (4) to operate at its maximum load; The ratio of the number of turns of the first coil (42) connected to the number of turns of the second coil (43) connected is determined by the ratio of the thermal buoyancy to the inertial force as follows: Formula (1); Among them, the value taken takes values from 1.1 to 1.2, takes values from 0.6 to 0.7, N1 and N2 are the number of turns connected to the first coil (42) and the second coil (43) respectively; among which the number of turns of N2 is not less than 100 turns; among which is generally in the range of 0.2 - 0.

5. If the value of is less than 0.2 or greater than 0.5, then the number of turns is set with the value at 0.2 or 0.5, that is, when the value of is less than 0.2, then the number of turns is set with 0.2; when the value of is greater than 0.5, then the number of turns is set with 0.5; The ratio of thermal buoyancy to inertial force is as follows: Formula (2); wherein, is the coefficient of thermal expansion of the molten steel, is the acceleration due to gravity, is the temperature difference between the incoming molten steel and the molten steel already existing in the tundish, is the characteristic flow velocity of the tundish molten steel, is the characteristic length of the tundish; Among them, the characteristic length of the tundish is calculated as follows: Formula (3); In the above formula is the vertical distance between the outlet of the induction heating channel and the outlet of the pouring chamber in the pouring chamber; The characteristic flow velocity of the molten steel in the tundish is calculated by the following formula: Formula (4); Among them, is the number of pouring chamber outlets, is the cross-sectional area of the billet, is the drawing speed of the billet, is the density of the billet, is the number of induction heating channels, is the inner diameter of the induction heating channel, is the density of the molten steel.

2. A steel continuous casting induction heating tundish according to claim 1, characterized in that, The combined winding method of the coils is such that the axes of at least two coils are perpendicular to each other.

3. A steel continuous casting induction heating tundish according to claim 2, characterized in that, The number of the induction heating channels (3) is two, and one induction heating device (4) is provided on each induction heating channel (3).

4. A continuous casting induction heating tundish for steel according to claim 3, characterized in that, The currents connected to the coils are in the same direction, have the same magnitude, and are connected to the same power supply.

5. A continuous casting induction heating tundish for steel according to claim 4, characterized in that, The number of turns of the first coil (42) connected is greater than the number of turns of the second coil (43) connected.

6. A control method for an induction heating tundish for continuous casting of steel, based on an induction heating tundish for continuous casting of steel according to any one of the above claims 1-5, characterized in that S1: At the initial stage of molten steel pouring or when the superheat is high, the induction heating device does not need to be turned on. When the molten steel temperature is lower than the set threshold, the induction heating device is turned on; S2: Determine the specific values of N1 and N2 through formula (1), and connect the number of turns of the first coil (42) and the second coil (43) according to the specific values of N1 and N2; S3: Connect the power supply to energize the first coil (42) and the second coil (43). By setting the ratio of the number of turns of the first coil (42) and the second coil (43) connected, the electromagnetic force that is large at the top and small at the bottom in the induction heating channel (3) is adjusted to an electromagnetic force that is small at the top and large at the bottom, and then the flow form of the molten steel at the outlet of the induction heating channel (3) is adjusted from a downward flow to an upward flow; S4: At the end of pouring, when the molten steel is lower than the induction heating channel (3), turn off the induction heating device.

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