Method for controlling solidification structure of high-grade non-oriented silicon steel based on pulse current

Abstract

A method for controlling a solidification structure of high-grade non-oriented silicon steel based on pulse current comprises the steps that a high-grade silicon steel alloy raw material is selected, and rare earth elements are added; molten steel is smelted in an electric arc furnace, and an online analysis instrument is used for monitoring components; in the re-continuous casting process, an adjustable pulse power supply is adopted, and the current frequency, amplitude and application time are optimized; utilizing a machine learning model to predict defects and automatically adjusting process parameters; an intelligent cooling system is adopted, and the surface defect risk is reduced by controlling the cooling speed and reducing thermal stress; then uniform heat treatment is carried out, and a layered heating technology is used to ensure that the internal structure is uniform; and then the casting blank is heated to the hot rolling temperature, then a gapless rolling technology is adopted for cold rolling of the hot-rolled plate, and after cold rolling, a nano coating technology is adopted for surface treatment. Through the nano coating technology, the corrosion resistance, the wear resistance and the oxidation resistance of the cold-rolled plate are remarkably improved, and the service life is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of controlling the solidification structure of high-grade non-oriented silicon steel, and in particular relates to a method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current. Background Art

[0002] Electrical steel is mainly divided into oriented and non-oriented silicon steel, among which non-oriented silicon steel is further divided into low-grade, medium-grade and high-grade silicon steel, and the grade is generally related to the Si content of the steel. Low-grade non-oriented silicon steel has phase change during the rolling process, so the requirements for the solidification structure of the ingot are not high. However, high-grade non-oriented silicon steel has no phase change, so the surface quality of the finished product will be affected by the solidification structure of the ingot. The higher the columnar crystal rate of the ingot, the greater the risk of corrugated defects on the surface of the high-grade non-oriented silicon steel. Therefore, in order to regulate the solidification structure of high-grade non-oriented silicon steel, a method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current is specially invented. Summary of the invention

[0003] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0004] In view of the problems of the above or existing methods for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current, the present invention is proposed.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: The embodiment of the present invention provides a method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current, comprising: selecting high-grade silicon steel alloy raw materials and adding rare earth elements; smelting molten steel in an electric arc furnace, controlling the chemical composition and temperature, and using an online analytical instrument to monitor the composition; in the continuous casting process, using an adjustable pulse power supply to optimize the current frequency, amplitude and application time; real-time monitoring of the solidification of the ingot, combining with a computer vision system to analyze the surface quality, using a machine learning model to predict defects and automatically adjust process parameters; then slowly taking out of the furnace, using an intelligent cooling system to control the cooling rate, reduce thermal stress, and reduce the risk of surface defects; then performing uniform heat treatment, using layered heating technology to ensure uniform internal structure; then heating the ingot to the hot rolling temperature, and then using a gapless rolling technology to cold-roll the hot-rolled plate, and using nano-coating technology for surface treatment after cold rolling.

[0006] As a preferred solution of the method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current described in the present invention, the silicon content of the high-grade silicon steel is 3.0%-4.5%, and the iron content is above 95%.

[0007] As a preferred solution of the method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current of the present invention, wherein: the high-grade silicon steel alloy raw material is selected and rare earth elements are added, including: During the smelting process, rare earth elements are added to the molten steel in the form of alloys. The temperature is controlled at 1500-1600°C when added to the molten steel, and the amount of rare earth elements added is 0.01%-0.5%.

[0008] As a preferred solution of the method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current described in the present invention, wherein: the molten steel is smelted in an electric arc furnace, the chemical composition and temperature are controlled, and the composition is monitored using an online analytical instrument, including: using a spectrometer to monitor the composition, real-time chemical composition analysis, including the content of carbon, silicon, manganese, phosphorus, sulfur and alloy elements, the sampling frequency is set to once per minute, the temperature and composition data are recorded in real time through a PLC system, and the operating parameters in the furnace are automatically adjusted according to the online analysis results.

[0009] As a preferred solution of the method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current described in the present invention, wherein: in the continuous casting process, an adjustable pulse power supply is used to optimize the current frequency, amplitude and application time, including: setting the current frequency to 300 Hz, the current amplitude to 600 A, applying current for 3 seconds at the initial application, standing for 17 seconds, observing the temperature and flow state, applying current for 5 seconds in the middle application, standing for 15 seconds, continuing to observe, and applying current for 10 seconds at the end of the application, standing for 10 seconds, and observing the solidification process.

[0010] As a preferred solution of the method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current described in the present invention, the method comprises: using a machine learning model to predict defects and automatically adjust process parameters, including: using a convolutional neural network to identify defect types, inputting real-time image data into a trained convolutional neural network, performing defect prediction, analyzing model output, and determining defect types and risk levels; if an increased risk of surface cracks is predicted, the system automatically reduces the current amplitude or adjusts the application time.

[0011] As a preferred solution of the method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to the present invention, wherein: the slow furnace discharge adopts an intelligent cooling system to control the cooling rate to reduce thermal stress and reduce the risk of surface defects, including: setting different cooling rates according to different stages of the billet: initial cooling 0-20s, controlling the cooling rate to 1°C / s, and rapidly reducing the billet surface temperature; In the middle stage of cooling, the cooling rate is controlled at 0.5°C / s for 20-60s to reduce thermal stress. In the late stage of cooling, the cooling rate is controlled at 0.2°C / s for more than 60s to further reduce the risk of surface defects. Ensure that the temperature of the ingot is reduced to below 600°C before demolding.

[0012] As a preferred solution of the method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to the present invention, wherein: the uniform heat treatment is then carried out, and the layered heating technology is used to ensure the uniformity of the internal structure, including: layered heating is carried out according to the height of the ingot, and is set to 3 layers: the heating temperature of the first layer is set to 900°C, and the holding time is 30 minutes; the heating temperature of the second layer is set to 850°C, and the holding time is 40 minutes; the heating temperature of the third layer is set to 800°C, and the holding time is 50 minutes.

[0013] As a preferred solution of the method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to the present invention, wherein: the ingot is heated to the hot rolling temperature, and then the hot-rolled plate is cold-rolled by adopting the gapless rolling technology, including: the hot rolling temperature is set at 1100-1300°C, the heating time is 30min-60min, the hot rolling equipment adopts a multi-pass hot rolling mill, the rolling speed is set at 1-5 m / min, the number of rolling passes is 4-6 times, and the plate thickness is checked after each rolling pass; the cold rolling temperature is maintained at 25-300°C, and the rolling speed is set at 3-8 m / min to ensure efficient cold rolling.

[0014] As a preferred embodiment of the method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to the present invention, the surface treatment using nano-coating technology after cold rolling comprises: using a spray gun to evenly spray the coating liquid on the surface of the plate at a spraying distance of 15-30 cm, immersing the plate in the coating liquid for a holding time of 1-5 min; placing the coated plate in a well-ventilated environment to dry naturally for 1-2 h, and then using an oven for thermal curing at a temperature set at 80-120°C for 30-60 min.

[0015] The beneficial effects of the present invention are as follows: the present invention significantly improves the corrosion resistance, wear resistance and oxidation resistance of the cold-rolled plate through nano-coating technology, and prolongs the service life. The coating treatment significantly improves the surface smoothness, reduces the friction coefficient, and reduces the wear in the subsequent processing process. After cleaning and surface treatment, the adhesion between the coating and the substrate is enhanced, ensuring the stability of the coating in various application environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them: Figure 1 A process flow chart of a method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current provided in an embodiment of the present invention.

[0017] Figure 2 A schematic diagram of the use of electric pulses in a method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current provided in an embodiment of the present invention.

[0018] Figure 3 A schematic diagram of electric pulse frequency and voltage of a method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current provided in an embodiment of the present invention.

[0019] Figure numerals: 1. Electric pulse equipment; 2. Crystallizer; 3. Ingot low magnification. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0021] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0023] Example 1 Reference Figure 1~Figure 3 , is an embodiment of the present invention, which provides a method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current, comprising: S1: Select high-grade silicon steel alloy raw materials and add rare earth elements.

[0024] Preferably, the silicon content of high-grade silicon steel is 3.0%-4.5%, and the iron content is above 95%. During the smelting process, rare earth elements are added to the molten steel in the form of alloys. When added to the molten steel, the temperature is controlled at 1500-1600°C, and the amount of rare earth elements added is 0.01%-0.5%.

[0025] Furthermore, if the molten steel is 1000kg, the addition amount is 0.1kg (0.01%) to 5kg (0.5%).

[0026] Slowly add the rare earth alloy into the molten steel to ensure uniform dispersion. It can be added in the form of ingots. At 1500-1600°C, add in batches to avoid drastic temperature fluctuations. Use a mechanical stirring device to keep the molten steel at 1500-1600°C for 5-10 minutes to promote the full reaction of the rare earth elements with the molten steel. Monitor the color and reaction status of the molten steel to ensure uniform distribution of alloy elements. After stirring is completed, take samples from the furnace for chemical composition analysis.

[0027] S2: Melt molten steel in an electric arc furnace, control chemical composition and temperature, and monitor composition using online analytical instruments.

[0028] Preferably, a spectrometer is used for composition monitoring and real-time chemical composition analysis, including the content of carbon, silicon, manganese, phosphorus, sulfur and alloy elements. The sampling frequency is set to once per minute, and the temperature and composition data are recorded in real time through the PLC system. According to the online analysis results, the operating parameters in the furnace are automatically adjusted.

[0029] Furthermore, based on real-time data, the PLC system automatically adjusts the furnace operating parameters (such as heating power and alloy element addition): If a certain element is too low, the PLC will automatically instruct to increase the amount of that element added; If an element exceeds the limit, the PLC will automatically instruct to reduce the furnace temperature or change the heating strategy.

[0030] The operator can view the composition and temperature changes of the molten steel in real time through the monitoring interface. If the composition exceeds the set range, the PLC system will issue an alarm to prompt the operator to take measures. Samples are taken from the molten steel every hour for laboratory analysis to verify the accuracy of the spectral analysis results.

[0031] S3: During the re-casting process, an adjustable pulse power supply is used to optimize the current frequency, amplitude and application time.

[0032] Preferably, the current frequency is set to 300 Hz, the current amplitude is 600 A, the current is applied for 3 seconds at the initial stage of application, and then allowed to stand for 17 seconds to observe the temperature and flow state, the current is applied for 5 seconds in the middle stage of application, and then allowed to stand for 15 seconds and continue to observe, and the current is applied for 10 seconds at the end of application, and then allowed to stand for 10 seconds to observe the coagulation process.

[0033] Furthermore, the molten steel is heated to 1500-1600°C to ensure that the alloy and rare earth elements have fully reacted. Apply initial pulse current: current parameter settings: frequency: 300 Hz, current amplitude: 600 A, application time: apply pulse current for 3 seconds, let it stand for 17 seconds after applying the current, do not apply current, observe the flow state and temperature changes of the molten steel, use an infrared thermometer to monitor the surface and internal temperature of the molten steel, record slight temperature fluctuations, observe the flow of the molten steel through a camera, and confirm whether the fluidity of the molten steel changes after the current is applied.

[0034] Apply pulse current in the mid-term stage, and apply mid-term pulse current: the current parameters remain unchanged: frequency: 300 Hz, current amplitude: 600 A, application time: apply pulse current for 5 seconds, standing time: stand for 15 seconds after applying current, continue to observe the temperature and flow state of the molten steel, monitor whether the temperature drops or rises significantly, record the correlation between temperature and solidification trend, observe the surface fluctuation and flow trend of the molten steel, and confirm the influence of pulse current on the flow state.

[0035] In the final stage, a pulse current is applied. The current parameters continue to remain unchanged: frequency: 300 Hz, current amplitude: 600 A, application time: apply pulse current for 10 seconds, standing time: stand for 10 seconds after applying the current. Focus on observing the solidification of the molten steel, monitor the rate of decrease of the surface temperature of the molten steel, pay special attention to the temperature gradient during the solidification process, observe whether the flow of the molten steel slows down, and record whether the surface of the molten steel begins to solidify to form a solid layer.

[0036] S4: Real-time monitoring of the solidification of the ingot, analysis of the surface quality in combination with a computer vision system, and use of a machine learning model to predict defects and automatically adjust process parameters.

[0037] Preferably, a convolutional neural network is used to identify defect types, real-time image data is input into a trained convolutional neural network, defect prediction is performed, and the model output is analyzed to determine the defect type and its risk level; if an increased risk of surface cracks is predicted, the system automatically reduces the current amplitude or adjusts the application time.

[0038] Furthermore, the camera collects high-resolution images of the billet surface in real time and sends the images to the computer for processing through a high-speed data transmission channel. The acquisition frequency is 30 frames per second to ensure that the image data can cover the entire surface of the billet. The collected images are preprocessed, including denoising, graying, contrast enhancement, etc., to improve the recognition accuracy of the CNN model. The running time of the preprocessing algorithm is controlled within 100 milliseconds to ensure the real-time processing of data. The preprocessed image data is input into the pre-trained CNN model, and the model hierarchy includes convolutional layers, pooling layers, fully connected layers, etc. The model matches the identified features with the trained defect library and classifies the defect types, including cracks: surface crack risk, pores: the possibility of pore formation during casting, scale: surface oxidation defect, corrugated defect: surface wavy corrugated defect, defect risk level assessment: risk assessment is performed for each type of defect, and the model outputs a risk value between 0-1 to indicate the severity of the defect.

[0039] Risk level: Low risk (<0.3): There are no obvious defects on the surface and the process remains unchanged; Medium risk (0.3-0.7): There are slight defects on the surface and the current parameters should be adjusted appropriately; High risk (>0.7): The surface defects are relatively serious and the process parameters need to be adjusted immediately.

[0040] Crack risk detection: If the CNN model predicts that the surface crack risk is greater than 0.7, the system triggers the adjustment mechanism to reduce the current amplitude: reduce the current amplitude from 600 A to 500 A, reduce energy input, and reduce thermal stress.

[0041] Adjust the current application time: adjust the current application time from 5 seconds to 3 seconds, and extend the standing time from 15 seconds to 20 seconds to allow the molten steel to gradually cool down and reduce the probability of cracks. The system will feed back the real-time image and defect detection results to the PLC control system. The PLC controller adjusts the frequency and application timing of the pulse power supply according to the risk level signal to optimize the solidification process of the ingot. The adjusted process parameters are applied in real time to the next pulse current application cycle to ensure the dynamic response of the process. Further image acquisition: After the process parameters are adjusted, continue to collect images of the ingot surface and input them into the CNN model for re-detection to confirm whether the defects have been alleviated. If the model detects that the crack risk drops below 0.3, the process adjustment stops; if the crack risk is still above 0.3, continue to adjust the process parameters until the risk drops to a safe range.

[0042] S5: Then slowly take it out of the furnace and use an intelligent cooling system to control the cooling speed, reduce thermal stress and reduce the risk of surface defects.

[0043] Preferably, different cooling rates are set according to different stages of the casting: Initial cooling 0-20s, control the cooling rate to 1°C / s, and quickly reduce the surface temperature of the ingot; Mid-term cooling for 20-60s, controlling the cooling rate to 0.5°C / s to reduce thermal stress; The post-cooling process lasted for more than 60 seconds, and the cooling rate was controlled at 0.2°C / s to further reduce the risk of surface defects; Ensure that the temperature of the ingot drops below 600°C before demoulding.

[0044] Furthermore, it is set to 1°C / s, and rapid cooling is achieved through the combination of high-pressure water spray and air cooling system.

[0045] Use temperature sensors to monitor the surface temperature of the ingot in real time to ensure that it quickly drops from 1200°C when it comes out of the furnace to below 1000°C. After the cooling system is started, the PLC controller controls the water flow rate and air volume of the cooling device based on the data fed back by the temperature sensor. Water spray rate: controlled at 30 L / min, the spray water temperature is 20°C, and the surface of the ingot is evenly covered through multiple nozzles. Wind speed of the air cooling system: set to 15 m / s to ensure a uniform cooling process. The initial cooling time is 0-20 seconds, and the surface temperature should drop from 1200°C to about 1000°C.

[0046] Set to 0.5°C / s to control the smoothness of cooling. The temperature target in the mid-term stage is to further reduce from 1000°C to 800°C. After the initial cooling, the PLC system reduces the spray intensity and the wind speed of the air cooling system according to the temperature sensor data. Water spray rate: reduced to 15 L / min, the spray water temperature remains unchanged, and the spraying continues evenly. Wind speed of the air cooling system: reduced to 10 m / s to ensure that the surface and internal temperature of the ingot drops evenly to prevent excessive thermal stress due to rapid cooling. The temperature should drop from 1000°C to 800°C within 20 to 60 seconds. The PLC system dynamically adjusts the cooling rate to ensure smooth cooling within the target temperature range.

[0047] Set to 0.2°C / s for gradual and gentle cooling. The target temperature in the later cooling stage is to further reduce from 800°C to below 600°C to ensure that the temperature meets the standard before demolding. After the mid-term cooling is completed, the PLC system further reduces the spray and air cooling intensity so that the billet can be cooled gradually and evenly in the later cooling. Water spray rate: reduced to 5 L / min, the water temperature remains at 20°C to ensure gentle cooling. Wind speed of the air cooling system: reduced to 5 m / s to maintain a stable cooling environment. The later cooling time is more than 60 seconds, and the temperature should be reduced from 800°C to below 600°C to ensure that the billet does not crack when demolding.

[0048] S6: Then a uniform heat treatment is carried out, using layered heating technology to ensure a uniform internal structure.

[0049] Preferably, heating is performed in layers according to the height of the casting, and is set to 3 layers: The first layer set the heating temperature to 900°C and the holding time to 30min; The second layer set the heating temperature to 850°C and the holding time to 40min; The heating temperature of the third layer was set to 800°C and the holding time was 50 min.

[0050] Furthermore, assuming that the total height of the ingot is 1200 mm, it is divided into three heating layers, each with a height of 400 mm, namely the first layer (0-400 mm), the second layer (400-800 mm) and the third layer (800-1200 mm).

[0051] In the bottom area of ​​the ingot (0-400 mm), the heating device is set to 900°C, and the heating speed of this area is adjusted by the multi-zone heating control device to make it heat up evenly. It is set to 5°C per minute to ensure a gradual rise from room temperature to 900°C to avoid excessive surface stress caused by too fast heating. After reaching 900°C, keep the temperature stable and keep it warm for 30 minutes to ensure that the temperature of this layer of ingot is uniform. The temperature of the bottom area of ​​the ingot is monitored in real time through the PLC system to ensure uniformity. The data fed back by the temperature sensor is displayed in real time. If the temperature deviation exceeds ±5°C, the PLC system automatically adjusts the power of the heating device to maintain the temperature within the target range.

[0052] The heating setting of the middle area (400-800 mm) is 850°C, and the multi-zone heating equipment is controlled by the PLC system to gradually heat this area to 850°C. It is set to 4°C per minute to slowly heat the middle area of ​​the ingot to ensure that the internal structure does not produce excessive stress during the heating process. After reaching 850°C, keep the temperature stable and keep it warm for 40 minutes to allow the heat to be evenly transferred to the inside of the ingot. The temperature sensor is installed in the middle of the ingot, and the temperature of this area is monitored in real time by the PLC system, and the data is also fed back to the controller. If the temperature deviation exceeds ±5°C, the system will automatically adjust the heater output power to ensure that the temperature of the middle layer is stable at 850°C.

[0053] The heating of the upper area (800-1200 mm) is set to 800°C, and the PLC system continues to control the heating equipment to slowly heat up this area. It is set to 3°C per minute to ensure that the top of the ingot is slowly heated to 800°C to avoid thermal stress concentration caused by too fast heating in the top area. After reaching 800°C, the temperature is kept stable and kept warm for 50 minutes to ensure that the heat is evenly transferred to the uppermost layer of the entire ingot. The temperature sensor installed in the top area monitors the temperature changes through the PLC system. If the temperature deviation exceeds ±5°C, the system automatically adjusts the heating intensity.

[0054] Ensure that the zone temperature is at 800°C for 50 minutes.

[0055] S7: The ingot is then heated to the hot rolling temperature, and then the hot-rolled plate is cold-rolled using the gapless rolling technology, and the surface is treated using the nano-coating technology after cold rolling.

[0056] Preferably, the hot rolling temperature is set at 1100-1300°C, the heating time is 30min-60min, the hot rolling equipment adopts a multi-pass hot rolling mill, the rolling speed is set at 1-5 m / min, the number of rolling is 4-6 passes, and the thickness of the plate is checked after each rolling; the cold rolling temperature is maintained at 25-300°C, and the rolling speed is set to 3-8 m / min to ensure efficient cold rolling. Use a spray gun to evenly spray the coating liquid on the surface of the plate, the spraying distance is 15-30cm, and the plate is immersed in the coating liquid for 1-5min; the coated plate is placed in a well-ventilated environment to dry naturally for 1-2h, and then used in an oven for heat curing, the temperature is set at 80-120°C, and the time is 30-60min.

[0057] Application Examples Apply a unidirectional pulse current to the molten steel in the crystallizer. Figure 1 , connect the high-frequency power supply 1 to the 380V three-wire four-phase power supply air switch, and connect it with 2~4 cables ≥10mm2; connect the output negative pole of the high-frequency power supply to the roller table 3 of the straightening machine with 2~4 cables ≥100mm2, and connect the output positive pole of the high-frequency power supply to the molten steel inserted in the crystallizer 2 with 2~4 cables ≥100mm2, and connect it to the electrode connector. The installation method is as follows: Figure 1 As shown; when working, bake the electrode to a red state, turn on the high-frequency power switch, insert the electrode into the crystallizer 10~400cm below the molten steel liquid level, and fix the electrode; after the rectifier, filter out the positive pulse current, retain the negative pulse current, and adjust the voltage to -30~0V. The voltage frequency diagram is shown in Figure 2 , adjust the current to 0~2000A, and the frequency to 1~100HZ. After the production is completed, turn off the high-frequency power switch and remove the electrode from the crystallizer.

[0058] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current, characterized in that: include: Select high-grade silicon steel alloy raw materials and add rare earth elements; Melt molten steel in an electric arc furnace, control chemical composition and temperature, and monitor composition using online analytical instruments; During the re-casting process, an adjustable pulse power supply is used to optimize the current frequency, amplitude and application time; Monitor the solidification of the ingot in real time, analyze the surface quality with a computer vision system, and use machine learning models to predict defects and automatically adjust process parameters; Then slowly take it out of the furnace, use an intelligent cooling system to control the cooling speed, reduce thermal stress and reduce the risk of surface defects; Then a uniform heat treatment is carried out, using a layered heating technique to ensure a uniform internal structure; The ingot is then heated to the hot rolling temperature, and then the hot-rolled plate is cold-rolled using gapless rolling technology. After cold rolling, nano-coating technology is used for surface treatment.

2. The method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to claim 1, characterized in that: The high-grade silicon steel contains 3.0%-4.5% silicon and more than 95% iron.

3. The method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to claim 1, characterized in that: The high-grade silicon steel alloy raw material is selected and rare earth elements are added, including: During the smelting process, rare earth elements are added to molten steel in the form of alloys. The temperature is controlled at 1500-1600°C when added to the molten steel, and the amount of rare earth elements added is 0.01%-0.5%.

4. The method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to claim 1, characterized in that: The molten steel is melted in an electric arc furnace, the chemical composition and temperature are controlled, and the composition is monitored using online analytical instruments, including: Use a spectrometer to monitor composition and conduct real-time chemical composition analysis, including the content of carbon, silicon, manganese, phosphorus, sulfur and alloy elements. The sampling frequency is set to once per minute. The temperature and composition data are recorded in real time through the PLC system. According to the online analysis results, the operating parameters in the furnace are automatically adjusted.

5. The method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to claim 1, characterized in that: In the continuous casting process, an adjustable pulse power supply is used to optimize the current frequency, amplitude and application time, including: Set the current frequency to 300 Hz and the current amplitude to 600 A. Apply current for 3 seconds at the initial stage of application, let stand for 17 seconds, and observe the temperature and flow state. Apply current for 5 seconds in the middle stage of application, let stand for 15 seconds, and continue to observe. Apply current for 10 seconds at the end of application, let stand for 10 seconds, and observe the solidification process.

6. The method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to claim 1, characterized in that: The method of using a machine learning model to predict defects and automatically adjust process parameters includes: Convolutional neural networks are used to identify defect types. Real-time image data is input into the trained convolutional neural network for defect prediction. The model output is analyzed to determine the defect type and its risk level. If an increased risk of surface cracks is predicted, the system automatically reduces the current amplitude or adjusts the application time.

7. The method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to claim 1, characterized in that: The slow furnace removal adopts an intelligent cooling system to control the cooling speed, reduce thermal stress and reduce the risk of surface defects, including: According to the different stages of the casting, different cooling rates are set: Initial cooling is 0-20s, and the cooling rate is controlled at 1℃ / s to quickly reduce the surface temperature of the casting; Mid-term cooling for 20-60s, controlling the cooling rate to 0.5℃ / s to reduce thermal stress; The subsequent cooling is more than 60s, and the cooling rate is controlled at 0.2℃ / s to further reduce the risk of surface defects; ensure that the temperature of the ingot is reduced to below 600℃ before demolding.

8. The method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to claim 1, characterized in that: The heat treatment is then carried out uniformly, using layered heating technology to ensure uniform internal structure, including: Heating is performed in layers according to the height of the ingot, and is set to 3 layers: The heating temperature of the first layer is set to 900°C and the holding time is 30 minutes; The second layer set the heating temperature to 850°C and the holding time to 40 minutes; The heating temperature of the third layer is set to 800°C and the holding time is 50 minutes.

9. The method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to claim 1, characterized in that: The casting is then heated to a hot rolling temperature, and then the hot-rolled sheet is cold-rolled using a gapless rolling technology, including: The hot rolling temperature is set at 1100-1300℃, the heating time is 30min-60min, the hot rolling equipment adopts a multi-pass hot rolling mill, the rolling speed is set at 1-5m / min, the number of rolling passes is 4-6, and the plate thickness is checked after each rolling pass; the cold rolling temperature is maintained at 25-300℃, and the rolling speed is set at 3-8m / min to ensure efficient cold rolling.

10. The method for controlling the solidification structure of high-grade non-oriented silicon steel based on pulse current according to claim 1, characterized in that: The surface treatment using nano coating technology after cold rolling includes: Use a spray gun to evenly spray the coating liquid on the surface of the board at a spraying distance of 15-30cm, immerse the board in the coating liquid for 1-5min; place the coated board in a well-ventilated environment to dry naturally for 1-2h, and then use an oven for heat curing at a temperature set at 80-120℃ for 30-60min.

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