A method for eliminating corrugation defects of high-grade non-oriented silicon steel produced by CSP process

Abstract

This invention belongs to the field of non-oriented silicon steel technology and discloses a method for eliminating corrugation defects in high-grade non-oriented silicon steel produced by the CSP process. The method includes the following steps: 1) smelting steel to obtain steel with the target composition; 2) continuous casting to form a billet, controlling the superheat of the molten steel in the tundish and the continuous casting speed, and setting up electromagnetic stirring in the secondary cooling zone, controlling the current and frequency of the electromagnetic stirring; 3) heating the billet and hot rolling to obtain a hot-rolled plate; 4) the hot-rolled plate undergoes subsequent processes such as coiling, pickling, normalizing, cold rolling, annealing, and coating to obtain the high-grade non-oriented silicon steel finished product. Based on a comprehensive consideration of the CSP production line equipment capabilities, this invention significantly improves the equiaxed crystal ratio of the billet through electromagnetic stirring in the secondary cooling zone and optimization of the superheat of the molten steel in the tundish and the continuous casting speed, thereby eliminating corrugation defects on the surface of the finished product, while ensuring that no slag inclusions appear on the surface of the finished product, resulting in good manufacturability.

Description

Technical Field

[0001] This invention belongs to the field of non-oriented silicon steel technology, specifically relating to a method for eliminating corrugation defects in high-grade non-oriented silicon steel produced by the CSP process. Background Technology

[0002] High-grade non-oriented electrical steel, due to its excellent properties such as low core loss and low magnetostriction, is widely used in the manufacture of cores for large motors and drive motors for electric vehicles, and is a soft magnetic alloy with a large consumption volume in the machinery and electrical industries. Currently, the production of high-grade non-oriented silicon steel mostly adopts the traditional thick slab process, and the CSP (compact strip production) process is rarely used. Because the CSP process for producing electrical steel offers advantages such as good as-cast microstructure, fine and uniform hot-rolled microstructure, uniform temperature, good sheet shape, energy saving, and high yield, the application of CSP production lines for the production of high-grade non-oriented silicon steel has a very broad prospect.

[0003] In China, the CSP process for producing electrical steel has been rapidly promoted and developed. However, the production of non-oriented silicon steel products is still concentrated on low and medium grades, and has not yet involved high-grade non-oriented silicon steel. This is because when the silicon content of cold-rolled non-oriented silicon steel is >1.7% and the carbon content is ≤0.01%, the presence of large amounts of Si and Al shrinks the γ phase region. There is no phase transformation in the material during the entire thermal history process, which leads to the columnar crystals being easily coarsened during continuous casting. The surface of the finished product often shows uneven corrugated defects along the rolling direction. These defects reduce the lamination factor, worsen the magnetic properties and interlayer resistance of the insulating film, and increase noise when assembled into iron cores, directly affecting the performance and lifespan of motors or transformers.

[0004] Regarding methods for eliminating corrugated defects in high-grade non-oriented silicon steel produced using the CSP process, the relevant research is as follows:

[0005] In their paper "Texture Analysis of Corrugation Defects in High-Grade Non-Oriented Silicon Steel Produced by CSP Process" published in December 2015, Rong Zhe et al. studied the generation mechanism of corrugation defects in high-grade non-oriented electrical steel produced by the CSP process. They used EBSD technology to detect and analyze the texture of samples from the hot rolling and normalizing processes. They proposed that a large number of strip-shaped rotating cubic variable fibers in the central layer of the hot-rolled plate are the root cause of corrugation defects in the final product. Normalizing can reduce corrugation defects, but cannot completely eliminate them.

[0006] Patent CN111961980A discloses a method for producing thin-gauge, high-grade non-oriented silicon steel using a CSP (Continuous Processing) process. Through composition and process design, especially strict control over the ratio of Si, Al, and Mn content, it ensures that the (Si+Al) content remains within the range of 1.8% to 2.8%, with multiple phase transformations occurring during billet cooling, homogenization, and rolling. This effectively improves the microstructure of the hot-rolled sheet and eliminates corrugation defects. The mechanism for eliminating corrugation defects still relies on multiple phase transformations. However, high-grade non-oriented silicon steel often has a (Si+Al) content exceeding 3%, making it impossible to improve the microstructure of the hot-rolled sheet through phase transformations.

[0007] Patent CN111719078A discloses a method for producing non-oriented silicon steel to eliminate corrugated defects. First, the composition is optimized, and a suitable process route is adopted, particularly decarburization annealing in a bell-type furnace. Utilizing the temperature gradient inside and outside the steel coil and the decarburization channel, a grain structure growing along the thickness direction is formed, vertically cutting off the original columnar crystalline deformation structure along the rolling direction, thus obtaining a more uniform ferrite structure and eliminating corrugated defects. However, bell-type furnace annealing has a long production cycle and suffers from problems such as uneven structure and magnetic properties at the beginning and end of the process.

[0008] Patent CN114250420A discloses a method for producing high-grade non-oriented silicon steel 50BW350 using bell-type intermediate annealing. Through special chemical design, Sb element is added, and the electromagnetic properties are improved by optimizing the product's structure and microstructure. The Si content is appropriately reduced, and the Mn content is increased. The influence of coarse fiber structure from hot rolling is eliminated by a secondary cold rolling method, resulting in a high-grade non-oriented silicon steel product without surface corrugation defects. However, bell-type furnace intermediate annealing and secondary cold rolling also have the problems of long process flow and high cost.

[0009] Patent CN111531138A discloses a method for producing non-oriented electrical steel through continuous casting and rolling of thin slabs. This method controls the size of columnar crystals in the slab during continuous casting, then controls the reduction during hot rolling and finish rolling, and employs a high finishing temperature to allow the hot-rolled slab microstructure to undergo sufficient dynamic recrystallization, breaking down the columnar crystals. Combined with high-temperature coiling, this results in a more uniform, coarser-grained hot-rolled recrystallized microstructure, avoiding corrugated defects caused by incomplete recrystallization and resulting fibrous structures. However, for high-grade non-oriented silicon steel with high (Si+Al) content, since CSP lacks the large reduction deformation during rough rolling at high temperatures, relying solely on the large reduction deformation during finish rolling and high-temperature coiling cannot achieve the fully dynamic recrystallization driving force required for hot rolling. Furthermore, high-temperature coiling also presents challenges such as difficulties in subsequent pickling.

[0010] The above literature and patents address the corrugation defects of high-grade non-oriented silicon steel in the CSP process by optimizing the process from aspects such as composition control, phase transformation, normalization, bell-type furnace annealing, and secondary cold rolling. However, they all have certain limitations, cannot completely eliminate corrugation defects, and have high production costs or may bring other new problems. Summary of the Invention

[0011] The technical problem to be solved by this invention is to address the shortcomings of existing technologies by improving a method for eliminating corrugated defects in the production of high-grade non-oriented silicon steel using the CSP process. Based on a comprehensive consideration of the CSP production line equipment capabilities, this invention significantly improves the equiaxed crystal ratio of the billet by using electromagnetic stirring in the secondary cooling zone and optimizing the superheat of the molten steel in the tundish and the continuous casting speed, thereby eliminating corrugated defects on the surface of the finished product. At the same time, it ensures that no slag inclusions appear on the surface of the finished product, resulting in good manufacturability.

[0012] To address the technical problem proposed in this invention, this invention provides a method for eliminating corrugated defects in high-grade non-oriented silicon steel produced by the CSP process, comprising the following steps:

[0013] 1) Steel smelting: Molten iron is pretreated and desulfurized, then enters the converter for smelting, and then undergoes vacuum decarburization and alloying to obtain molten steel with the target composition;

[0014] 2) Continuous casting billet: Molten steel enters the crystallizer through the tundish and initially solidifies. The billet with liquid core is pulled out of the crystallizer and enters the secondary cooling zone to continue cooling and solidification until it is completely solidified to form a billet.

[0015] 3) Billet heating and hot rolling: The billet is homogenized and kept warm in the tunnel furnace, and then enters the hot rolling mill for hot rolling to obtain hot rolled plate;

[0016] 4) Subsequent processes: After hot-rolled plates are coiled, pickled, normalized, and then cold-rolled to the finished thickness, they are annealed and coated to obtain high-grade non-oriented silicon steel finished products.

[0017] In the above scheme, the weight percentage content of Si in the high-grade non-oriented silicon steel is 2-4%, and the weight percentage content of Als is 0.1-1.5%.

[0018] In the above scheme, the superheat ΔT of the molten steel in the tundish satisfies the following formula:

[0019] (Si%+5Als%)×100≤ΔT≤(2Si%+5Als%)×200

[0020] In the formula, ΔT is the superheat of molten steel in the tundish, in °C; Si% is the weight percentage content of Si in the steel; and Als% is the weight percentage content of Als in the steel.

[0021] In the above scheme, the second cooling zone is equipped with a roller electromagnetic stirrer for electromagnetic stirring.

[0022] Furthermore, the electromagnetic stirring is installed in at least one of the three fan-shaped sections 1-3 of the secondary cooling zone.

[0023] Furthermore, the number of coil turns of the roller electromagnetic stirrer is 100-300 turns.

[0024] Furthermore, the current I of the electromagnetic stirring satisfies the following formula:

[0025] I≥500-(Si%+0.5Als%)×2000

[0026] In the formula, I is the electromagnetic stirring current, in A; Si% is the weight percentage content of Si in the steel; Als% is the weight percentage content of Als in the steel.

[0027] Furthermore, the frequency f of the electromagnetic stirring satisfies the following formula:

[0028] 10-(Si%+2Als%)×100≤f≤20-(Si%+2Als%)×100

[0029] In the formula, f is the electromagnetic stirring frequency in Hz; Si% is the weight percentage content of Si in the steel, and Als% is the weight percentage content of Als in the steel.

[0030] In the above scheme, the casting speed V of the continuous casting satisfies the following formula:

[0031] 7-(Si%+0.5Als%)×100≤V≤9-(Si%+0.5Als%)×100

[0032] In the formula, V is the continuous casting speed, in m / min; Si% is the weight percentage content of Si in the steel; Als% is the weight percentage content of Als in the steel.

[0033] In the above scheme, when the billet with liquid core passes through the electromagnetic stirring area of ​​the secondary cooling zone, the length of the liquid core inside the billet is 4-5m, and the thickness of the solidified billet shell is 15-25mm.

[0034] In the above scheme, the thickness of the billet is 60-90mm, and the equiaxed crystal ratio of the billet is ≥50%.

[0035] In the above scheme, the homogenization temperature of the billet in the tunnel furnace is 950-1150℃, and the holding time is ≥30min.

[0036] In the above scheme, the finishing rolling temperature of the hot continuous rolling is 800-950℃, and the thickness of the hot-rolled plate is 1-2mm.

[0037] In the above scheme, the winding temperature is 600-750℃.

[0038] In the above scheme, the pickling temperature is 60-80℃ and the pickling time is 30-60s.

[0039] In the above scheme, the normalization temperature is 820-1020℃, and the normalization soaking time is 45-75s.

[0040] In the above scheme, the cold rolling is carried out in a single cold rolling process.

[0041] In the above scheme, the thickness of the finished product is 0.2-0.5mm.

[0042] In the above scheme, the annealing is carried out in a mixed atmosphere of H2 and N2, the annealing temperature is 900-1050℃, and the annealing soaking time is 30-60s.

[0043] The technical concept of this invention is as follows:

[0044] The root cause of corrugated defects is the well-developed columnar crystals in the cast billet. Due to the high silicon and aluminum content, no phase transformation occurs during hot rolling, so these defects cannot be completely eliminated by large-reduction hot rolling, high-temperature normalization, and annealing. Ultimately, this affects the product stacking factor and worsens magnetic anisotropy. In this case, electromagnetic stirring is the most suitable method. Because high-grade alloys have a higher content of nucleating elements in the molten steel, the electromagnetic stirring effect of high-grade steel is significantly better than that of medium-grade steel. Silicon and aluminum elements, as the main crystallization nuclei during solidification, promote the formation of equiaxed crystals during continuous casting. That is, the higher the silicon and aluminum content, the easier it is for equiaxed crystal nuclei to grow, and the more obvious the electromagnetic stirring effect.

[0045] According to the principle of electromagnetic stirring, for electromagnetic stirring in the secondary cooling zone to achieve good results, the billet must have a certain liquid core thickness after passing through the stirring section. Under the action of electromagnetic thrust, the molten steel is stirred and dendrites are broken, and the molten steel undergoes secondary crystallization, thereby obtaining a high equiaxed crystal ratio.

[0046] The surface magnetic field of the electromagnetic stirrer has the greatest impact on electromagnetic thrust, and this surface magnetic field is directly proportional to the number of coil turns. Due to space constraints and to reduce electromagnetic power, the number of coil turns is controlled to a certain extent. Therefore, increasing the current intensity is the most effective way to increase electromagnetic thrust. However, excessively high electromagnetic stirring current will increase the stirrer's capacitance, raising costs and power consumption. Therefore, considering both the quality and economic efficiency of slab electromagnetic stirring, the current intensity should be appropriately increased to achieve maximum electromagnetic thrust with minimal electromagnetic power. In this invention, the electromagnetic stirring current I is set to I≥500-(Si%+0.5Als%)×2000, which can make the equiaxed crystal ratio of the cast slab ≥50%.

[0047] Increasing the frequency increases the electromagnetic thrust, but on the other hand, it also increases the magnetic field attenuation coefficient, thus decreasing the electromagnetic thrust. Therefore, the change in electromagnetic thrust with frequency is not monotonic, but has a maximum value. Simultaneously, increasing the frequency also increases the induced voltage, thereby increasing the electromagnetic power; this change is not a simple linear relationship. Therefore, this invention sets the electromagnetic stirring frequency f to 10 - (Si%+2Als%)×100 ≤ f ≤ 20 - (Si%+2Als%)×100 to obtain the maximum electromagnetic thrust.

[0048] As the continuous casting speed increases, the temperature gradient and solidification rate within the solidification two-phase region of the billet decrease, the undercooling at the solid-liquid interface decreases, the primary dendrite spacing of the billet increases, the transformation from columnar crystals to equiaxed crystals occurs earlier, and the equiaxed crystal ratio increases. Appropriately increasing the casting speed can improve the equiaxed crystal ratio at the center of the non-oriented silicon steel billet. Therefore, this invention sets the continuous casting speed V to V≥7-(Si%+0.5Als%)×100. Simultaneously, with the increase in casting speed, the fluctuation value of the liquid surface in the crystallizer becomes higher, the slag-gold surface becomes more active, and the liquid slag becomes more abundant. At this time, the four walls of the crystallizer have a good lubrication effect, and the probability of slag entrapment also increases. When the casting speed is too high, the crystallizer is not sufficiently lubricated, the fluidity of the crystallizer protective slag is poor, and the billet shell does not have enough time to solidify to the required thickness, easily leading to steel leakage accidents. Therefore, this invention sets the maximum casting speed V≤9-(Si%+0.5Als%)×100.

[0049] Under high-temperature conditions during tundish casting, the superheat of the molten steel inside the billet shell is relatively high. Fine equiaxed crystals falling from the billet shell are quickly melted by the molten steel, unable to nucleate and continue growing into equiaxed grains. At this point, the solidification end of the billet is prolonged, easily causing fluctuations in the liquid level of the crystallizer and resulting in surface defects such as slag inclusions. Therefore, reducing the superheat of the molten steel in continuous casting helps to limit the growth of columnar crystals during solidification and increase the nucleation and growth area of ​​equiaxed crystals. However, excessively low superheat can easily lead to nozzle clogging, causing accidents that prevent continuous casting. Therefore, this invention controls the superheat ΔT of the molten steel in the tundish to: (Si%+5Als%)×100≤ΔT≤(2Si%+5Als%)×200.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] Based on a comprehensive consideration of the CSP production line equipment capabilities, this invention sets up electromagnetic stirring in the secondary cooling zone, controls the current and frequency of the electromagnetic stirring, and combines this with the optimization of the tundish molten steel superheat and continuous casting speed. This can significantly improve the equiaxed crystal ratio of the billet, making the equiaxed crystal ratio of the billet ≥50%, thereby eliminating corrugation defects on the surface of the finished product, while ensuring that no slag inclusion defects appear on the surface of the finished product, resulting in good manufacturability. Detailed Implementation

[0052] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0053] In the following examples, the chemical composition and weight percentage content of the high-grade non-oriented silicon steel are shown in Table 1, with the balance being Fe and unavoidable inclusions.

[0054] Table 1. Chemical composition and weight percentage of steel

[0055] Example 1 0.0021 0.0012 0.0015 0.0015 0.02 0.0015 3.05 1.15 0.52 Example 2 0.0016 0.0009 0.0017 0.0019 0.01 0.0021 2.25 0.56 0.27

[0056] Example 1 and Comparative Example 1

[0057] A method for eliminating corrugated defects in high-grade non-oriented silicon steel produced by the CSP process includes the following steps:

[0058] 1) Steel smelting: Molten iron is pretreated and desulfurized, then enters the converter for smelting, and then undergoes vacuum decarburization and alloying to obtain molten steel with the target composition;

[0059] 2) Continuous casting billet: Molten steel enters the crystallizer through the tundish and initially solidifies. The billet with liquid core is pulled out from the crystallizer and enters the secondary cooling zone to continue cooling until it is completely solidified to form a billet with a thickness of 70mm.

[0060] A roller-type electromagnetic stirrer is installed in the secondary cooling zone for electromagnetic stirring. When the billet with liquid core passes through the electromagnetic stirring area of ​​the secondary cooling zone, the liquid core length and billet shell thickness of the billet are shown in Table 2.

[0061] Based on the weight percentage content of Si and Als in the steel, Si% = 3.05% and Als% = 1.15%, the superheat ΔT of the molten steel in the tundish is calculated to be 8.8-23.7℃, the continuous casting speed V is 3.37-5.37m / min, the electromagnetic stirring current I ≥ 427.5A, and the frequency f is 4.65-14.65Hz.

[0062] 3) Billet heating and hot rolling: The billet is homogenized and held at 1020℃ in a tunnel furnace for 35 minutes. Then it enters the seven-stand hot rolling mill for hot rolling. The finishing rolling temperature is 870℃ to obtain a hot rolled plate with a thickness of 2mm.

[0063] 4) Subsequent processes: The hot-rolled sheet is coiled at 680℃, pickled at 72℃ for 43s, normalized at 900℃ for 56s, and then cold-rolled to a finished thickness of 0.3mm. It is then annealed in a mixed atmosphere of H2:N2 = 1:4 at a temperature of 960℃ for 35s. Finally, a coating is applied to obtain a high-grade non-oriented silicon steel finished product.

[0064] Table 2 Main Process Parameters

[0065]

[0066]

[0067] Table 3 Properties of Cast Billets and Finished Products

[0068] Example 1-1 52 No corrugations, no slag inclusions / Examples 1-2 59 No corrugations, no slag inclusions / Examples 1-3 54 No corrugations, no slag inclusions / Examples 1-4 65 No corrugations, no slag inclusions / Examples 1-5 61 No corrugations, no slag inclusions / Comparative Example 1-1 42 It has corrugated structure, with a height of 30μm. The electric stirring current is too low Comparative Examples 1-2 37 It has corrugated structure and a height of 36μm. The electric stirring frequency is too low. Comparative Examples 1-3 33 It has corrugated structure and a height of 42μm. The electric stirring frequency is too high. Comparative Examples 1-4 38 It has corrugated structure and a height of 38μm. Low continuous casting speed Comparative Examples 1-5 Steel leakage, no billet formed Steel leakage, no finished product obtained. The continuous casting speed is too high. Comparative Examples 1-6 40 It has corrugations, a height of 43μm, and slag inclusions. The intermediate bread was overheated.

[0069] Example 2 and Comparative Example 2

[0070] A method for eliminating corrugated defects in high-grade non-oriented silicon steel produced by the CSP process includes the following steps:

[0071] 1) Steel smelting: Molten iron is pretreated and desulfurized, then enters the converter for smelting, and then undergoes vacuum decarburization and alloying to obtain molten steel with the target composition;

[0072] 2) Continuous casting billet: Molten steel enters the crystallizer through the tundish and initially solidifies. The billet with liquid core is pulled out from the crystallizer and enters the secondary cooling zone to continue cooling until it is completely solidified to form a billet with a thickness of 75mm.

[0073] A roller-type electromagnetic stirrer is installed in the secondary cooling zone for electromagnetic stirring. When the billet with liquid core passes through the electromagnetic stirring area of ​​the secondary cooling zone, the liquid core length and billet shell thickness of the billet are shown in Table 2.

[0074] Based on the weight percentage content of Si and Als in the steel, Si% = 2.25% and Als% = 0.56%, the superheat ΔT of the molten steel in the tundish is calculated to be 5.05-14.6℃, the continuous casting speed V is 4.47-6.47m / min, the electromagnetic stirring current I ≥ 449.4A, and the frequency f is 6.63-16.63Hz.

[0075] 3) Billet heating and hot rolling: The billet is homogenized and held at a temperature of 975℃ in a tunnel furnace for 43 minutes. Then it enters the seven-stand hot rolling mill for hot rolling. The finishing rolling temperature is 912℃ to obtain a hot-rolled plate with a thickness of 1.8mm.

[0076] 4) Subsequent processes: The hot-rolled sheet is coiled at 712℃, pickled at 75℃ for 55s, normalized at 900℃ for 62s, and then cold-rolled to a finished thickness of 0.35mm. It is then annealed in a mixed atmosphere of H2:N2 = 1:4 at a temperature of 990℃ for 35s. Finally, a coating is applied to obtain a high-grade non-oriented silicon steel finished product.

[0077] Table 2 Main Process Parameters

[0078]

[0079] Table 3 Properties of Cast Billets and Finished Products

[0080]

[0081]

[0082] As can be seen from the above embodiments and comparative examples, by setting up electromagnetic stirring in the secondary cooling zone, controlling the current and frequency of electromagnetic stirring, and combining it with the optimization of the superheat of molten steel in the tundish and the continuous casting speed, the equiaxed crystal ratio of the billet can be significantly improved, making the equiaxed crystal ratio of the billet ≥50%, thereby eliminating corrugation defects on the surface of the finished product, and ensuring that no slag inclusion defects appear on the surface of the finished product.

[0083] The above embodiments are merely examples for clear illustration and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations, and any obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for eliminating corrugated defects in high-grade non-oriented silicon steel produced by the CSP process, characterized in that, Includes the following steps: 1) Steelmaking to obtain high-grade non-oriented silicon steel with the target composition, wherein the weight percentage content of Si is 2-4% and the weight percentage content of Als is 0.1-1.5%; 2) Molten steel enters the crystallizer through the tundish and initially solidifies. The billet with liquid core is pulled out from the crystallizer and enters the secondary cooling zone to continue cooling until it is completely solidified and forms a billet. The superheat ΔT of molten steel in the tundish satisfies the formula: (Si%+5Als%)×100≤ΔT≤(2Si%+5Als%)×200; The casting speed V in continuous casting satisfies the formula: 7-(Si%+0.5Als%)×100≤V≤9-(Si%+0.5Als%)×100; The secondary cooling zone is equipped with an electromagnetic stirrer. The current I and frequency f of the electromagnetic stirrer satisfy the following formula: I≥500-(Si%+0.5Als%)×2000; 10-(Si%+2Als%)×100≤f≤20-(Si%+2Als%)×100; In the formula, ΔT is the superheat of molten steel in the tundish, in °C; V is the continuous casting speed, in m / min; I is the electromagnetic stirring current, in A; f is the electromagnetic stirring frequency, in Hz; Si% is the weight percentage content of Si in the steel; Als% is the weight percentage content of Als in the steel. 3) Heating the billet and hot rolling it continuously to obtain hot-rolled plates; 4) After hot-rolled plates are coiled, pickled, normalized, and then cold-rolled to the finished thickness, they are annealed and coated to obtain high-grade non-oriented silicon steel finished products.

2. The method for eliminating corrugated defects in high-grade non-oriented silicon steel produced by the CSP process according to claim 1, characterized in that, The electromagnetic stirring is installed in at least one of the three fan-shaped sections of the secondary cooling zone.

3. The method for eliminating corrugated defects in high-grade non-oriented silicon steel produced by the CSP process according to claim 1, characterized in that, The electromagnetic stirring uses a roller electromagnetic stirrer, and the number of coil turns of the roller electromagnetic stirrer is 100-300.

4. The method for eliminating corrugated defects in high-grade non-oriented silicon steel produced by the CSP process according to claim 1, characterized in that, When the billet with liquid core passes through the electromagnetic stirring zone of the secondary cooling zone, the length of the liquid core inside the billet is 4-5m, and the thickness of the solidified billet shell is 15-25mm.

5. The method for eliminating corrugated defects in high-grade non-oriented silicon steel produced by the CSP process according to claim 1, characterized in that, The thickness of the cast billet is 60-90mm, and the equiaxed crystal ratio of the cast billet is ≥50%.

6. The method for eliminating corrugated defects in high-grade non-oriented silicon steel produced by the CSP process according to claim 1, characterized in that, The thickness of the hot-rolled plate is 1-2 mm.

7. The method for eliminating corrugated defects in high-grade non-oriented silicon steel produced by the CSP process according to claim 1, characterized in that, The thickness of the finished product is 0.2-0.5 mm.

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