A flow field control device and method for slab continuous casting crystallizer

Abstract

A flow field control device and method for a slab continuous casting crystallizer includes: a traveling wave magnetic field generator arranged on the upper part of both sides of the wide face of the slab continuous casting crystallizer, near the lower part of the molten steel meniscus to the upper edge of the submerged entry nozzle outlet, wherein the electromagnetic force generated by the traveling wave magnetic field generator is parallel to the wide face of the slab; DC static magnetic field generators are respectively arranged on the lower part of both sides of the wide face of the slab continuous casting crystallizer and on the molten steel streams on both sides of the submerged entry nozzle, wherein the two static magnetic field generators are perpendicular to the wide face of the slab and the magnetic field directions are opposite; several temperature measuring points and corresponding temperature measuring elements are arranged at intervals along the height direction on the two narrow face crystallizer copper plates of the slab continuous casting crystallizer, wherein at least one temperature measuring point on each of the two narrow face crystallizer copper plates is less than 100 mm away from the upper edge of the narrow face crystallizer copper plate; the distance from each temperature measuring point to the surface of the crystallizer copper plate is the same; and a controller, wherein the traveling wave magnetic field generator, the static magnetic field generator, and the temperature measuring elements are electrically connected to the controller.

Description

Technical Field

[0001] This invention relates to continuous casting technology, and in particular to a flow field control device and method for slab continuous casting crystallizer. Background Technology

[0002] The crystallizer is the heart of continuous casting, and the flow state of the molten steel within it directly determines the final quality of the continuously cast product. During production, technical means are typically employed to optimize and control the molten steel flow field within the crystallizer, preventing phenomena such as slag entrapment, liquid level fluctuations, and excessively deep steel flow impact.

[0003] In production, additional technical means are needed to optimize and control the flow field of the crystallizer. Generally, the methods for optimizing the flow field of the crystallizer can be divided into two types: passive and active.

[0004] Passive systems are mainly achieved through optimizations such as submersible nozzle structure and tilt angle.

[0005] Active methods primarily achieve this through the application of external fields, such as electromagnetic vortex nozzles, electromagnetic stirring in the crystallizer, and electromagnetic braking. Electromagnetic stirring uses electromagnetic force to cause the molten steel to rotate. The rotating molten steel acts as a scouring agent at the solidification front, carrying away inclusions and bubbles and promoting their flotation and removal, ultimately improving the surface quality of the continuously cast billet. Electromagnetic braking, on the other hand, applies a static magnetic field to the flowing molten steel, using the induced Lorentz force to reduce its absolute flow velocity. When the static magnetic field acts below the nozzle, it can reduce the impact depth of the molten steel, which is beneficial for the flotation of inclusions and bubbles; when the static magnetic field acts on the meniscus, it can stabilize the liquid surface fluctuations and reduce slag entrainment.

[0006] In the actual production process of slab continuous casting, the flow field inside the crystallizer is extremely complex and constantly changes throughout the entire casting process. For example, flow deviation often occurs during continuous casting, meaning that there is a significant difference in the flow velocity of the molten steel on both sides of the nozzle, resulting in an asymmetry where one side has a faster flow velocity and the other side has a slower flow velocity. Similarly, localized excessively high flow velocities or eddies can easily occur near the meniscus. Electromagnetic stirring or electromagnetic braking, as technical means to optimize and control the flow field of the crystallizer, has been widely used in actual production. However, extensive production practice shows that using a single electromagnetic technology cannot adapt to improving the flow field of the crystallizer under complex operating conditions such as changes in casting speed; more advanced flow field control devices and methods are needed.

[0007] In recent years, flow field control methods employing two magnetic fields simultaneously have emerged, such as Chinese patents CN201080019323 and CN201080019325, which use a lower braking and upper stirring method. However, the magnetic yokes of the two devices in this patent are interconnected, meaning that the lower electromagnetic braking magnetic field, once activated, will also generate a magnetic field in the upper stirrer. Furthermore, the biggest drawback of this method is that the lower static magnetic field easily interferes with the traveling wave magnetic field of the upper electromagnetic stirring. Analyzing the principle of electromagnetic stirring, it can be seen that the upper moving magnetic field drives the molten steel to rotate horizontally, but the static magnetic field component transmitted from the lower static magnetic field to the upper stirrer actually hinders the movement of the molten steel; these two aspects are clearly contradictory.

[0008] Chinese patent ZL201710107017.0 discloses a method for controlling the flow field in a slab continuous casting mold. This method employs an electromagnetic stirring device and an electromagnetic braking device to control the flow field in the slab continuous casting mold. The electromagnetic stirring device is positioned in the upper region on both sides of the wide face of the mold, while the electromagnetic braking device is positioned in the lower region on both sides of the wide face of the mold. The upper and lower electromagnetic braking devices are independent of each other. The upper electromagnetic stirring device is installed between the upper edge of the nozzle outlet and the meniscus, while the lower electromagnetic braking device is a regional braking device located below the nozzle outlet on both sides, acting on the area through which the nozzle outflow stream flows between the nozzle and the narrow face of the mold. The upper and lower electromagnetic braking devices are powered by two separate power supplies, and the current intensity is controlled independently. The upper electromagnetic stirring device uses a traveling wave magnetic field, and the magnetic field on both sides of the wide face of the mold drives the molten steel to move horizontally relative to each other. By employing electromagnetic stirring and braking devices, and utilizing different magnetic field forms, electromagnetic force magnitudes, and application locations, the patent precisely controls the application of electromagnetic force according to the specific conditions during continuous casting, thereby achieving a superior flow field and improving billet quality. However, the patent does not provide specific methods for online adjustment of electromagnetic parameters or a corresponding flow field detection device, which affects its practical application in actual production operations. Summary of the Invention

[0009] The purpose of this invention is to provide a flow field control device and method for slab continuous casting crystallizer, which can apply electromagnetic fields to different positions of the crystallizer flow field in a targeted manner according to the real-time state of the crystallizer flow field and dynamically adjust the electromagnetic parameters, thereby maximizing the improvement of the crystallizer flow field and improving the surface quality of the continuously cast slab.

[0010] To achieve the above objectives, the technical solution of the present invention is as follows:

[0011] Besides factors such as steel purity, pouring temperature, casting speed, cooling intensity, and argon flow rate, the surface quality of continuously cast billets is significantly influenced by the use of electromagnetic stirring / electromagnetic braking. A crucial function of electromagnetic stirring / electromagnetic braking within the crystallizer is to alter the flow rate and direction of the molten steel through electromagnetic force. This improves the uniformity of the solidified shell, reduces the likelihood of inclusions and bubbles being trapped at the solidification front, promotes their buoyancy, and ultimately improves surface quality. Simultaneously, the electromagnetic force also leads to more uniform steel temperature and can appropriately increase the equiaxed crystal ratio. Therefore, electromagnetic flow control technology has become a key core technology for high-quality, high-efficiency production of slab continuously cast billets.

[0012] In the continuous casting process of slabs, molten steel enters the continuous casting mold through a submerged entry nozzle. After impacting the narrow face of the mold, the molten steel flows in both upward and downward directions, forming two circulating flows within the mold. The size and local velocity of these two circulating flows have a crucial impact on slab quality. Generally, a stable and moderate flow velocity distribution is beneficial to production, but it is difficult to detect and control in real time during actual production, especially since flow deviation often occurs during casting. Therefore, based on the aforementioned characteristics of the flow field in the mold, different forms of electromagnetic flow control technology can be used in different areas to artificially control the flow velocity of the molten steel using electromagnetic force, thereby forming an ideal flow field distribution. This invention utilizes different magnetic field forms, electromagnetic force magnitudes, and application locations to dynamically and precisely control electromagnetic parameters according to the specific conditions of the continuous casting process, thereby obtaining a superior flow field state and improving slab quality.

[0013] Specifically, the slab continuous casting crystallizer flow field control device of the present invention includes:

[0014] A traveling wave magnetic field generator is arranged on both sides of the upper part of the wide face of the slab continuous casting crystallizer, near the lower part of the molten steel meniscus to the upper edge of the submerged nozzle outlet. The electromagnetic force generated by the traveling wave magnetic field generator is parallel to the wide face of the slab.

[0015] DC static magnetic field generators are arranged on the lower part of both sides of the wide face of the slab continuous casting crystallizer and on the steel flow streams on both sides of the submerged entry nozzle. The two static magnetic field generators are perpendicular to the wide face of the slab continuous casting crystallizer and have opposite magnetic field directions.

[0016] On the two narrow-faced mold copper plates of the slab continuous casting mold, several temperature measuring points and corresponding temperature measuring elements are set at intervals along the height direction. At least one temperature measuring point on each of the two narrow-faced mold copper plates is less than 100mm away from the upper edge of the narrow-faced mold copper plate. The distance from each temperature measuring point to the working surface of the narrow-faced mold copper plate is the same.

[0017] The controller is electrically connected to the traveling wave magnetic field generator, the static magnetic field generator, and the temperature measuring element.

[0018] The present invention also provides a method for controlling the flow field in a slab continuous casting crystallizer, which includes the following steps:

[0019] 1) A traveling wave magnetic field is arranged on both sides of the upper part of the slab continuous casting crystallizer, near the lower part of the molten steel meniscus to the upper edge of the nozzle outlet. The electromagnetic force generated by the traveling wave magnetic field is parallel to the slab wide surface, causing the molten steel to flow horizontally in opposite directions near the two wide surfaces of the slab. The magnetic induction intensity of the traveling wave magnetic field can be adjusted according to the process requirements.

[0020] 2) DC static magnetic fields are respectively arranged on the steel flow streams on both sides of the lower submerged entry nozzle on both sides of the wide face of the slab continuous casting crystallizer. The two static magnetic fields are perpendicular to the wide face of the slab and the magnetic field directions are opposite. The magnetic induction intensity of the DC static magnetic field can be adjusted according to the process requirements.

[0021] 3) On the two narrow-faced crystallizer copper plates on the left and right sides of the slab continuous casting crystallizer, several temperature measuring points are set at intervals along the height direction. At least one temperature measuring point on each of the two narrow-faced crystallizer copper plates is less than 100mm away from the upper edge of the crystallizer copper plate. The distance from each temperature measuring point to the working surface of the narrow-faced crystallizer copper plate is the same.

[0022] 4) Determine the flow state of molten steel inside the crystallizer based on the real-time temperature readings at the temperature measuring points on the two narrow-faced copper plates.

[0023] Retrieve the real-time liquid level control height from the production process. Retrieve the real-time temperature detection values ​​corresponding to the temperature measuring points closest to the molten steel surface on the copper plates of the two narrow-faced crystallizers. Calculate the difference between the maximum and minimum temperature detection values ​​obtained within at least one minute. Detect and calculate two temperature differences on the two narrow-faced crystallizer copper plates, denoted as ΔT1 and ΔT2. Compare and select the maximum value, denoted as Tmax, in °C. Based on the value of Tmax, control the electromagnetic stirring parameters of the crystallizer, setting the electromagnetic stirring ampere-turns A to satisfy:

[0024] A = A0 × (1 - Tmax / 100)

[0025] A: Ampere-turns on the electromagnetic stirring coil, which is the value of the number of turns of the coil on each coil of the electromagnetic stirrer multiplied by the current;

[0026] A0: Baseline value, between 10,000 and 14,000;

[0027] The Tmax value is checked and recalculated every minute at least once. If the Tmax value changes by no more than 10%, the set value A remains unchanged. If the Tmax value changes by more than 10%, the value A is recalculated and recalculated.

[0028] 5) Determine the flow state of molten steel inside the crystallizer based on the location of the temperature measuring point corresponding to the maximum temperature detection value on the copper plates of the two narrow-faced crystallizers.

[0029] The temperature readings from each measuring point on the copper plates of the two narrow-faced crystallizers are recorded respectively. The distance L from the measuring point corresponding to the maximum temperature reading to the upper edge of the copper plate of the narrow-faced crystallizer is subtracted to obtain the distance difference ΔL1 (in mm). Based on the magnitude of ΔL1, the electromagnetic braking parameters are controlled, and the electromagnetic braking static magnetic field B is set to satisfy:

[0030] B = B0 × (1 + ΔL1 / 100), unit: Gauss;

[0031] B0: Static magnetic field reference value, between 1900 and 2300;

[0032] Every minute or so, the ΔL2 value is recalculated. If the difference between the ΔL2 and ΔL1 values ​​does not exceed 10%, the set value B remains unchanged. If the fluctuation between the ΔL2 and ΔL1 values ​​exceeds 10%, the value B is recalculated and set until the difference between the two ΔL values ​​does not exceed 10%.

[0033] Preferably, the straight-line distance between each temperature measuring point is 10–40 mm.

[0034] Preferably, in step 4), the Tmax value is detected and calculated again every 5 minutes.

[0035] Preferably, in step 5), the ΔL value is detected and calculated again every 5 minutes.

[0036] Existing technologies cannot directly detect the flow state of high-temperature molten steel inside the crystallizer, making it difficult to achieve dynamic control of the electromagnetic stirring and electromagnetic braking parameters of the crystallizer.

[0037] This invention is based on high-precision, high-density real-time temperature detection on the narrow surface of the copper plate in the crystallizer, which can indirectly reflect the flow state of molten steel in the crystallizer (such as flow deviation).

[0038] like Figure 5 As shown, the curves formed by the temperature detection values ​​of each temperature measuring point on the two narrow-face copper plates of the slab continuous casting mold each have a maximum temperature detection value. During production, the positions of the temperature measuring points corresponding to the maximum temperature detection values ​​on the two narrow-face copper plates may differ. When the position of the temperature measuring point corresponding to the maximum temperature detection value on one side of the narrow-face copper plate is higher than that on the other side, it indicates that the molten steel is biased towards that side, that is, there is a flow deviation of molten steel on both sides of the nozzle inside the mold.

[0039] The causes of flow deviation are multifaceted, such as nozzle blockage or bulging. This invention addresses this by installing an electromagnetic brake at the bottom of the crystallizer. On one hand, this reduces the impact depth of the molten steel flow; on the other hand, the molten steel, under the influence of the electromagnetic braking force, rises back to the meniscus of the crystallizer, further enhancing the upward reverse flow. Simultaneously, by adjusting the electromagnetic brake parameters, the flow velocity of the upward reverse flow of molten steel within the crystallizer can be adjusted, further optimizing the flow field and improving flow deviation.

[0040] See Figure 6 During the production process, the temperature at each temperature measuring point fluctuates continuously over time.

[0041] The temperature readings at various measuring points on the copper plate of the narrow-faced crystallizer are monitored. The measuring point with the highest temperature reading corresponds to the meniscus of the molten steel (where the molten steel temperature is highest). When the position of the measuring point with the highest temperature reading changes significantly, it indicates that the molten steel level fluctuates considerably.

[0042] When electromagnetic stirring drives molten steel to rotate using electromagnetic force, it inevitably increases the flow velocity of the molten steel near the meniscus, causing greater fluctuations in the molten steel surface. Therefore, by appropriately adjusting the electromagnetic stirring parameters based on the actual changes in the temperature measurement point where the maximum temperature is detected, the fluctuations in the molten steel surface can be reduced.

[0043] In summary, based on the above-mentioned temperature detection information and data analysis, the electromagnetic stirring and electromagnetic braking parameters can be controlled in a targeted manner, ultimately achieving the goal of optimizing the flow field in the crystallizer.

[0044] The beneficial effects of this invention are:

[0045] The flow state of molten steel in the crystallizer directly determines the final surface quality of the continuously cast billet. When the impact depth of the molten steel is too deep, the inclusions in the molten steel cannot float up sufficiently and are captured by the solidified billet shell. When the meniscus fluctuates violently, defects such as slag entrapment are easily caused.

[0046] The use of electromagnetic flow control technology to improve the flow field in slab continuous casting molds has been validated in production, and electromagnetic stirring technology for molds has been widely applied in major steel mills across China. However, due to the complex and variable nature of actual production conditions, using a single, stable electromagnetic parameter is insufficient to meet the demands of high-quality and high-efficiency continuous casting production. In particular, the specific flow state of molten steel cannot be monitored in real time during production, which makes controlling the electromagnetic stirring and braking parameters of the mold extremely difficult. Typically, in actual production, the electromagnetic stirring parameters of the mold remain essentially constant, hindering further improvements in the final product quality.

[0047] This invention indirectly senses the flow state of molten steel in the crystallizer by using high-precision dynamic online detection of the temperature of the copper plate in the crystallizer. This allows for the provision of relatively accurate dynamic electromagnetic control methods for different real-time flow field conditions, effectively improving the flow field state in the crystallizer, achieving a better electromagnetic flow control effect, and ultimately obtaining high-quality continuously cast billets. Attached Figure Description

[0048] Figure 1 This is a front view of an embodiment of the slab continuous casting crystallizer flow field control device of the present invention;

[0049] Figure 2 This is a schematic diagram of the temperature measuring points on the copper plate of the narrow-face crystallizer in an embodiment of the present invention;

[0050] Figure 3 This is a perspective view of an embodiment of the present invention;

[0051] Figure 4 This is a top view of an embodiment of the present invention;

[0052] Figure 5 A graph showing the temperature measured at each temperature measurement point;

[0053] Figure 6 To detect the temperature change over time. Detailed Implementation

[0054] See Figure 1 , Figure 2 The slab continuous casting crystallizer flow field control device of the present invention includes:

[0055] A traveling wave magnetic field generator 3 is arranged between the upper part of the two wide-face crystallizer copper plates 101 of the slab continuous casting crystallizer 1, near the lower part of the molten steel meniscus, and the upper edge of the submerged nozzle 2 outlet 201. The electromagnetic force generated by the traveling wave magnetic field generator 3 is parallel to the wide face of the slab.

[0056] DC static magnetic field generators 4 are arranged on the lower part of both sides of the wide face of the slab continuous casting crystallizer 1 and on the steel flow streams 10 and 20 on both sides of the submerged entry nozzle 2. The two static magnetic field generators 4 are perpendicular to the wide face of the slab and have opposite magnetic field directions.

[0057] On the two narrow-faced crystallizer copper plates 102 of the slab continuous casting crystallizer 1, several temperature measuring points 5 and corresponding temperature measuring elements are set at intervals along the height direction. Furthermore, at least one temperature measuring point on each of the two narrow-faced crystallizer copper plates 101 is less than 100mm away from the upper edge of the narrow-faced crystallizer copper plate 102. The distance between each temperature measuring point and the working surface of the narrow-faced crystallizer copper plate is the same.

[0058] The controller (not shown in the figure) is electrically connected to the traveling wave magnetic field generator, the static magnetic field generator, and the temperature measuring element.

[0059] Example 1

[0060] Production conditions: continuous casting speed 1.6 m / s, width 1450 mm, thickness 250 mm; steel grade: IF steel plate; nozzle insertion depth (distance from the meniscus to the top edge of the nozzle) 210 mm. To address these conditions, 30 temperature measuring points are evenly spaced on the narrow copper plates of the two crystallizers, with a spacing of 12.5 mm between the measuring points. A traveling wave magnetic field stirrer is arranged at the top of the crystallizer, and two DC static magnetic fields are arranged at the bottom of the crystallizer. Using the device and method of this invention, the electromagnetic stirring and electromagnetic braking parameters can be dynamically adjusted online in real time according to the dynamic changes in the temperature of the narrow copper plates during production.

[0061] The parameters for the upper electromagnetic stirring are set as follows:

[0062] 1) Retrieve the real-time temperature readings from the two narrow-faced crystallizer copper plates, specifically from the points Pa and Pb closest to the molten steel surface. Based on these readings, calculate the difference between the maximum and minimum temperature readings on the two narrow-faced crystallizer copper plates within 2 minutes, denoted as ΔT1 and ΔT2. Compare the values ​​of ΔT1 and ΔT2, and record the largest difference as Tmax1. Calculate the stirring current ampere-turns A1 as follows:

[0063] A1 = 12000 × (1 - Tmax1 / 100)

[0064] After 5 minutes, Tmax2 is calculated again. If the change in Tmax2 compared to Tmax1 is within 10%, the stirring current setting remains unchanged. After another 5 minutes, Tmax3 is calculated again. If the change in Tmax3 compared to Tmax1 exceeds 10%, the electromagnetic stirring current ampere-turns A3 is recalculated as follows:

[0065] A3 = 12000 × (1 - Tmax3 / 100)

[0066] The above-mentioned electromagnetic stirring parameter adjustment process continues until production ends;

[0067] 2) Setting parameters for the lower electromagnetic brake

[0068] The distances from the upper edge of the copper plate of the two narrow-faced crystallizers to the maximum temperature readings of each plate are subtracted to obtain the distance difference ΔL1 (mm). Based on the magnitude of ΔL1, the electromagnetic braking parameters are controlled, and the electromagnetic braking static magnetic field is set to satisfy the following:

[0069] B1 = 2000 × (1 + ΔL1 / 100);

[0070] Where B: Electromagnetic braking static magnetic field, unit Gauss.

[0071] After 5 minutes, the ΔL2 value is checked and calculated again. If the change between ΔL2 and ΔL1 is no more than 10%, the set value B remains unchanged. After another 5 minutes, the ΔL3 value is checked and calculated again. If the change between ΔL3 and ΔL1 is more than 10%, the value B3 is recalculated and set to:

[0072] B3 = 2000 × (1 + ΔL3 / 100);

[0073] The above-mentioned electromagnetic braking parameter adjustment process continues until production ends.

[0074] By dynamically controlling the parameters of the two electromagnetic fields mentioned above online, high-quality continuous casting billets can be obtained.

[0075] Example 2

[0076] Production conditions: continuous casting speed 1.4m / s, width 1650mm, thickness 230mm; steel grade: IF steel plate, nozzle insertion depth (i.e., distance from the meniscus to the upper edge of the nozzle) is 190mm.

[0077] To address these operating conditions, 30 temperature measuring points are evenly spaced on the copper plates of the two narrow-faced crystallizers, with a spacing of 12.5 mm between the measuring points. A traveling wave magnetic field stirrer is arranged at the top of the crystallizer, and two DC static magnetic fields are arranged at the bottom of the crystallizer. Using the device and method of this invention, the electromagnetic stirring and electromagnetic braking parameters can be dynamically adjusted online in real time according to the dynamic changes in the temperature of the copper plates of the narrow-faced crystallizers during the production process.

[0078] The parameters for the upper electromagnetic stirring are set as follows:

[0079] 1) The liquid level control height corresponds to the nearest temperature measurement points Pa and Pb. Based on the temperature changes of Pa and Pb over time, calculate the maximum temperature measured on the copper plates of the two narrow-faced crystallizers within 5 minutes, subtracting the minimum temperature measured, and record these as ΔT1 and ΔT2. Compare the values ​​of ΔT1 and ΔT2, and select the maximum value as Tmax1. Calculate the stirring current ampere-turns A1 as follows:

[0080] A1 = 11000 × (1 - Tmax1 / 100)

[0081] After 5 minutes, Tmax2 is calculated again. If the change in Tmax2 compared to Tmax1 is within 10%, the stirring current setting remains unchanged. After another 5 minutes, Tmax3 is calculated again. If the change in Tmax3 compared to Tmax1 exceeds 10%, the electromagnetic stirring current ampere-turns A3 is recalculated as follows:

[0082] A3 = 11000 × (1 - Tmax3 / 100)

[0083] The above-mentioned electromagnetic stirring parameter adjustment process continues until production ends;

[0084] 2) Setting parameters for the lower electromagnetic brake

[0085] The distances from the measuring points corresponding to the maximum temperature values ​​of the copper plates in the two narrow-faced crystallizers to the upper edge of the copper plates are read and subtracted to obtain the distance difference ΔL1 (mm); based on the magnitude of ΔL1, the electromagnetic braking parameters are controlled, and the electromagnetic braking static magnetic field is set to satisfy:

[0086] B1 = 2100 × (1 + ΔL1 / 100);

[0087] Where B: Electromagnetic braking static magnetic field, unit Gauss.

[0088] After 5 minutes, the ΔL2 value is checked and calculated again. If the change between ΔL2 and ΔL1 is no more than 10%, the set value B remains unchanged. After another 5 minutes, the ΔL3 value is checked and calculated again. If the change between ΔL3 and ΔL1 is more than 10%, the value B3 is recalculated and set to:

[0089] B3 = 2100 × (1 + ΔL3 / 100);

[0090] The above-mentioned electromagnetic braking parameter adjustment process continues until production ends.

[0091] By dynamically controlling the parameters of the two electromagnetic fields mentioned above online, high-quality continuous casting billets can be obtained.

[0092] With users' increasing demands for steel product quality, and enterprises' own inherent requirements for efficient production, higher demands are being placed on the control of the flow field in slab crystallizers. The multi-magnetic field flow control device and method for crystallizers designed in this invention are flexible and controllable, with low difficulty in actual processing, manufacturing, and implementation. The equipment is easy to install and replace, and is expected to have a wide range of applications.

Claims

1. A method for controlling the flow field in a slab continuous casting mold, characterized in that, Includes the following steps: 1) A traveling wave magnetic field is arranged on both sides of the upper part of the slab continuous casting crystallizer, near the lower part of the molten steel meniscus to the upper edge of the nozzle outlet. The electromagnetic force generated by the traveling wave magnetic field is parallel to the slab wide surface, causing the molten steel to flow horizontally in opposite directions near the two wide surfaces of the slab. The magnetic induction intensity of the traveling wave magnetic field can be adjusted according to the process requirements. 2) DC static magnetic fields are respectively arranged on the steel flow streams on both sides of the lower submerged entry nozzle on both sides of the wide face of the slab continuous casting crystallizer. The two static magnetic fields are perpendicular to the wide face of the slab and the magnetic field directions are opposite. The magnetic induction intensity of the DC static magnetic field can be adjusted according to the process requirements. 3) On the two narrow-faced crystallizer copper plates on the left and right sides of the slab continuous casting crystallizer, several temperature measuring points are set at intervals along the height direction. At least one temperature measuring point on each of the two narrow-faced crystallizer copper plates is less than 100mm away from the upper edge of the crystallizer copper plate. The distance from each temperature measuring point to the working surface of the narrow-faced crystallizer copper plate is the same. 4) Determine the flow state of molten steel inside the crystallizer based on the real-time temperature readings at the temperature measuring points on the two narrow-faced copper plates. Retrieve the real-time liquid level control height from the production process. Retrieve the real-time temperature detection values ​​corresponding to the temperature measuring points closest to the molten steel surface on the copper plates of the two narrow-faced crystallizers. Calculate the difference between the maximum and minimum temperature detection values ​​obtained within at least one minute. Detect and calculate two temperature differences on the two narrow-faced crystallizer copper plates, denoted as ΔT1 and ΔT2. Compare and select the maximum value, denoted as Tmax, in °C. Based on the value of Tmax, control the electromagnetic stirring parameters of the crystallizer, setting the electromagnetic stirring ampere-turns A to satisfy: A = A0 × (1 - Tmax / 100) A: Ampere-turns on the electromagnetic stirring coil, which is the value of the number of turns of the coil on each coil of the electromagnetic stirrer multiplied by the current; A0: Baseline value, between 10,000 and 14,000; The Tmax value is recalculated every minute at least once. If the Tmax value changes by no more than 10%, the set value A remains unchanged. If the Tmax value changes by more than 10%, the A value will be recalculated and set. 5) Determine the flow state of molten steel inside the crystallizer based on the location of the temperature measuring point corresponding to the maximum temperature detection value on the copper plates of the two narrow-faced crystallizers. The temperature readings from each measuring point on the copper plates of the two narrow-faced crystallizers are recorded respectively. The distance L from the measuring point corresponding to the maximum temperature reading to the upper edge of the copper plate of the narrow-faced crystallizer is subtracted to obtain the distance difference ΔL1 (in mm). Based on the magnitude of ΔL1, the electromagnetic braking parameters are controlled, and the electromagnetic braking static magnetic field B is set to satisfy: B = B0 × (1 + ΔL1 / 100), unit: Gauss; B0: Static magnetic field reference value, between 1900 and 2300; Every minute or so, the ΔL2 value is recalculated. If the difference between the ΔL2 and ΔL1 values ​​does not exceed 10%, the set value B remains unchanged. If the fluctuation between the ΔL2 and ΔL1 values ​​exceeds 10%, the value B is recalculated and set until the difference between the two ΔL values ​​does not exceed 10%.

2. The method for controlling the flow field in a slab continuous casting crystallizer as described in claim 1, characterized in that, The straight-line distance between each temperature measuring point is 10–40 mm.

3. The method for controlling the flow field in a slab continuous casting crystallizer as described in claim 1 or 2, characterized in that, In step 4), the Tmax value is detected and calculated again every 5 minutes.

4. The method for controlling the flow field in a slab continuous casting mold as described in claim 1 or 2, characterized in that, In step 5), the ΔL value is checked and calculated again every 5 minutes.

5. The method for controlling the flow field in a slab continuous casting crystallizer as described in claim 3, characterized in that, In step 5), the ΔL value is checked and calculated again every 5 minutes.

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