A method for manufacturing a thin-gauge grain-oriented electrical steel sheet having excellent permeability

Abstract

The present application provides a manufacturing method of thin gauge oriented electrical steel sheet with excellent plate permeability, comprising the following steps: hot rolling heated billet; annealing the hot rolled sheet; cold rolling the annealed sheet to target thickness; decarburization annealing the cold rolled sheet; coating release agent and drying and coiling; secondary spraying release agent on the end face of the steel coil; high temperature annealing for secondary recrystallization of the obtained sheet; flat annealing and coating insulation coating; wherein, during the coating of release agent and drying and coiling, the thickness of the release agent is controlled to be 10-15 g / m 2 , and the coiling tension range is controlled to be 50-100 N / m 2 during the coiling process.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an oriented electrical steel sheet, and more specifically, to a method for manufacturing a thin-gauge (0.15-0.23 mm) oriented electrical steel sheet with excellent through-sheet properties. Background Technology

[0002] Electrical steel sheets are generally divided into grain-oriented electrical steel sheets and non-oriented electrical steel sheets. Among them, grain-oriented electrical steel sheets contain about 3% silicon and have a grain orientation of (110)

[001] crystal texture. They have excellent magnetic properties along the rolling direction and can be used as core materials for transformers, engines, generators and other electronic equipment.

[0003] The conventional production process of electrical steel sheets is as follows: ironmaking → steelmaking → hot rolling → pickling and normalizing → cold rolling → decarburization annealing → nitriding → isolation coating → high-temperature annealing → insulating coating → final annealing → finished product shearing → packaging. Among them, the isolation coating applied before high-temperature annealing has two main functions: (1) reacting with the silica on the surface of the steel sheet to produce the bottom layer of magnesium silicate glass film; (2) acting as an isolation agent to prevent the adhesion between layers during high-temperature annealing. The current mainstream production process uses magnesium oxide as the main insulating coating. A certain proportion of water and magnesium oxide powder are stirred in a mixing tank to form a uniform suspension. The coating is applied to the surface of the strip steel by a coating roller and then quickly dried to form a uniform powder coating on the surface of the strip steel. The strip steel is then rolled up to form a decarburized annealed steel coil.

[0004] The drawback of the above production process is that, due to the surface tension of the magnesium oxide coating liquid, the coating liquid at the edges shrinks towards the center before drying on the strip, resulting in an edge shrinkage effect at the very edge of the strip. This means that after drying, the outermost 1-3 mm of the strip is not covered by powder coating. The lack of powder coating coverage creates a lack of isolation, making the strip highly susceptible to layer-to-layer adhesion after high-temperature annealing. Adhesive strip is prone to edge cracking during subsequent uncoiling processes, and may even break directly on the uncoiler or be uncoilable and scrapped. The thinner the strip and the higher its silicon content, the more severe the adhesion phenomenon, and the worse the sheet permeability after high-temperature annealing. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the above-mentioned deficiencies of the prior art and provide a manufacturing method for an electrical steel sheet with excellent through-plate properties that can effectively avoid adhesion between the outermost layers of the strip during high-temperature annealing.

[0006] The technical problem it aims to solve can be addressed through the following technical solutions.

[0007] A method for manufacturing a thin-gauge oriented electrical steel sheet with excellent through-sheet properties includes the following steps: hot-rolling a heated steel billet; annealing the hot-rolled steel sheet; cold-rolling the annealed steel sheet to a target thickness; decarburizing and annealing the cold-rolled steel sheet; coating with a release agent and drying and coiling; performing a secondary spraying of the release agent on the end face of the steel coil; subjecting the resulting steel sheet to high-temperature annealing for secondary recrystallization; performing leveling annealing and coating with an insulating coating;

[0008] Its characteristic is that, when coating and drying the release agent, the thickness of the release agent is controlled at 10-15 g / m. 2 During the winding process, the winding tension is controlled within the range of 50-100 N / m. 2 .

[0009] As a further improvement to this technical solution, the volume ratio k of the release agent after coiling is controlled to be 0.05–0.15; the formula for calculating the volume ratio k is as follows:

[0010] k=m / (Π(R 2 -r 2 )×w×ρ 硅钢 )

[0011] Where m is the weighing weight of the coiled steel, Π is a constant, R is the outer diameter of the coiled steel, r is the inner diameter of the coiled steel, w is the strip width, and ρ is the density of silicon steel, taken as 7.85 kg / dm³. 3 .

[0012] As a further improvement to this technical solution, the separating agent is composed of the following components: 75-94.5% magnesium oxide powder, 5-20% calcium oxide powder, and 0.5-5% antimony sulfate. Furthermore, the particle size of the magnesium oxide powder and calcium oxide powder is between 1 μm and 10 μm.

[0013] As a further improvement to this technical solution, the steel plate to be coated contains 2.0–4.5 wt% silicon. Furthermore, the steel plate to be coated also contains 0.035–0.120 wt% C, 0.05–0.20 wt% Mn, 0.002–0.012 wt% S, 0.015–0.035 wt% Als, 0.001–0.010 wt% N, and the balance being Fe and unavoidable impurities.

[0014] In a preferred embodiment of the present invention, before hot rolling, the steel billet is heated in a temperature range below 1380°C and hot-rolled to obtain a hot-rolled steel plate of 2.0 to 3.0 mm; then hot-rolled annealing is performed at 1000 to 1150°C, followed by pickling and cold rolling to obtain a cold-rolled steel plate of 0.15 to 0.35 mm thickness; then decarburization annealing is performed in a humid atmosphere containing hydrogen and nitrogen at a temperature range of 800 to 900°C to obtain a steel plate.

[0015] In another preferred embodiment of the present invention, when the obtained steel plate is subjected to high-temperature annealing for secondary recrystallization, the annealing temperature is raised to above 1100°C in a mixed atmosphere of nitrogen and hydrogen, and after the secondary recrystallization is completed, it is uniformly heated at above 1150°C for at least 20 hours in a reducing atmosphere with a hydrogen content of above 50%.

[0016] As a further improvement to this technical solution, a secondary spraying of the release agent is carried out using an atomized electrostatic spraying method. This causes the atomized release agent coating particles to acquire a negative charge in a DC high-voltage electric field, and under the action of the electrostatic field, they flow directionally towards the exposed edge of the strip steel on the end face of the positively charged decarburized annealed steel coil, neutralizing and depositing into a uniform and firmly adhered thin film.

[0017] Furthermore, the electrostatic spraying method includes a spray gun connected to a compressed air control system. The spray gun is connected to the negative terminal of a high-frequency, high-voltage direct current source, while the steel coil is connected to the positive terminal. The paint is fed into the spray gun via compressed air and atomized within the gun using the pressure of another stream of compressed air. The atomized paint particles enter an electromagnetic field, acquire a negative charge, and then fly directionally to the positively charged end face of the steel coil. Further, the compressed air control system controls the output compressed air pressure to be 0.1–1 MPa; the output DC voltage to be 8–12 V; the operating current to be 50–200 mA; and the distance between the spray gun and the end face of the steel coil to be 10–50 cm.

[0018] Preferably, during the second spraying, the ratio of release agent to water is 1:5 to 1:10.

[0019] The manufacturing method using the above-mentioned technical solution provides a method for manufacturing grain-oriented electrical steel sheets that differs from previous methods. Based on the conventional grain-oriented electrical steel sheet manufacturing process, a release agent is applied a second time to the end face of the steel coil after decarburization annealing to cover the exposed parts at the outermost edge of the steel coil. High-temperature annealing is then performed to allow the second-applied release agent to react with the exposed parts at the outermost edge of the strip to form a glass film underlayer. This avoids adhesion between the layers at the outermost edge of the strip during high-temperature annealing, resulting in an electrical steel sheet with excellent through-sheet properties. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the apparatus for performing electrostatic spraying in this invention.

[0021] In the diagram: 1—Compressed air control system, 2—High-frequency high-voltage electrostatic generator, 3—Spray gun, 4—Separating agent paint tank, 5—Negatively charged paint particles, 6—Steel coil support, 7—Decarburized annealed steel coil. Detailed Implementation

[0022] The present invention provides a method for manufacturing thin-gauge grain-oriented electrical steel sheets with excellent through-sheet properties. This method is a further improvement on the conventional manufacturing process of grain-oriented electrical steel sheets and includes the following steps: manufacturing a steel billet; reheating the steel billet; hot rolling the reheated steel billet; annealing the hot-rolled steel billet; cold rolling the annealed steel sheet to adjust the steel sheet to the target thickness; decarburizing and annealing the cold-rolled steel sheet; coating with a release agent and drying and coiling; performing a second spraying of the release agent on the end face of the steel coil; performing a second recrystallization high-temperature annealing on the obtained steel sheet; performing leveling annealing and coating with an insulating coating.

[0023] This invention does not limit the composition of the initial steel billet, but ideally the steel sheet to be coated contains 2.0–4.5 wt% silicon. More preferably, the steel billet contains Si: 2.0–4.5 wt%, C: 0.035–0.120 wt%, Mn: 0.05–0.20 wt%, S: 0.002–0.012 wt%, Als: 0.015–0.035 wt%, N: 0.001–0.010 wt%, with the balance being Fe and unavoidable impurities.

[0024] The design considerations for controlling the Si content range are as follows: Si increases the resistance of the steel plate, which is very effective in reducing eddy current loss. If the Si content is below 2.0wt%, the eddy current loss of the finished product cannot be effectively reduced, while if the Si content is above 4.5wt%, the rollability of the steel plate deteriorates.

[0025] The design considerations for controlling the C content range are as follows: The C content needs to match the Si content to ensure that the reheated billet and plate obtain an appropriate proportion of austenitic phase (γ phase). Increasing the proportion of γ phase can utilize phase transformation rolling to obtain a finer hot-rolled microstructure and reduce (100) <011> The strength of the texture is unfavorable, and fine grains should be prevented. Since the solid solubility of nitrogen in the γ phase is 10 times greater than that in the α phase, increasing the proportion of the γ phase can also ensure that a large amount of fine AlN is obtained during rapid cooling after annealing of hot-rolled steel sheets. This is beneficial for the initial grains to be fine and uniform, and promotes the development of secondary recrystallization.

[0026] The design considerations for controlling Mn and S content ranges are primarily aimed at improving hot-rolling manufacturability. Due to S grain boundary segregation, hot brittleness easily occurs in hot-rolled billets when the Mn / S ratio is too low. To improve hot workability, the Mn / S ratio is controlled between 2.5 and 3.5, because Mn significantly reduces the solid solubility of S and forms compounds. Furthermore, Mn is easily oxidized in decarburizing annealing atmospheres, thus affecting the formation of the underlying layer. High S content easily leads to line crystal formation and makes S removal difficult during final high-temperature annealing. In addition, Mn and S can also generate MnS, an inhibitor required for secondary recrystallization.

[0027] The design considerations for controlling the Al and N content ranges are as follows: Al and N are the main inhibitory elements of AlN in high-magnetic-induction grain-oriented silicon steel. In order to obtain a moderate inhibitory force, it is necessary to precisely control the range of Al and N in the billet, and adjust the size and distribution of AlN to ensure that the Gaussian nuclei with good orientation undergo perfect secondary recrystallization, thereby obtaining excellent magnetic properties.

[0028] The steel billet is reheated at a temperature below 1380℃ and hot-rolled to obtain a hot-rolled steel sheet with a thickness of 2.0–3.0 mm. It is then hot-rolled and annealed at 1000–1150℃, followed by pickling and cold rolling to obtain a cold-rolled steel sheet with a thickness of 0.15–0.35 mm. Next, it undergoes decarburization annealing at approximately 800–900℃ in a humid atmosphere containing hydrogen and nitrogen to obtain a decarburized annealed steel sheet. The decarburized annealed steel sheet is coated with a conventional release agent using coating rollers and then dried and coiled.

[0029] Based on the above steps, the key innovation of this invention lies in controlling the thickness of the release agent and the winding tension of the decarburized annealed coil to maintain the release agent's volume ratio within a certain range, thus preparing a specialized release agent coating for electrostatic spraying. The end face of the decarburized annealed coil is then coated with the release agent a second time using an atomized electrostatic spraying method. The atomized release agent coating particles acquire a negative charge in a DC high-voltage electric field and, under the influence of the electrostatic field, flow directionally towards the exposed edge of the positively charged decarburized annealed coil strip, neutralizing and depositing into a uniform and firmly adhered thin film. This provides full coverage of the exposed charged metal portions of the coil end face that are not covered with release agent powder due to edge shrinkage. The portions already covered with release agent remain uncharged due to the insulating effect of the release agent, preventing repeated spraying and avoiding any adverse effects on the coil quality.

[0030] Furthermore, the following process conditions are controlled:

[0031] (1) The thickness of the conventional release agent applied by the coating machine to the decarburized annealed steel coil is controlled at 10-15 g / m. 2 .

[0032] (2) During the decarburized annealed steel coil winding process, the winding tension should be controlled within the range of 50-100 N / m. 2 .

[0033] (3) By controlling the thickness of the release agent and the winding tension, the volume ratio k of the release agent after winding is controlled to be 0.05~0.15. The formula for calculating the volume ratio k is as follows:

[0034] k=m / (Π(R 2 -r 2 )×w×ρ 硅钢 )

[0035] Where m is the weighing weight of the coiled steel, Π is a constant, R is the outer diameter of the coiled steel, r is the inner diameter of the coiled steel, w is the strip width, and ρ is the density of silicon steel, taken as 7.85 kg / dm³. 3 .

[0036] Adjustments are made according to the formula for calculating the product ratio k of the produced steel coils. When the calculated product ratio is <0.05, the product ratio of the subsequent produced steel coils can be increased by increasing the coiling tension or reducing the thickness of the release agent. Conversely, the adjustment is made in the opposite direction.

[0037] (4) such as Figure 1 As shown, the apparatus for implementing the above electrostatic spraying method includes: a compressed air control system 1, a high-frequency high-voltage electrostatic generator 2, a spray gun with a nozzle 3, and a release agent / coating tank 4. A high-frequency, high-voltage direct current is applied through the spray gun 3 to create a strong electromagnetic field around the end face of the steel coil (i.e., the decarburized annealed steel coil 7 in the figure) (the spray gun is connected to the negative pole, and the steel coil to the positive pole). The coating material is delivered to the spray gun from the pressure tank by compressed air. Inside the spray gun, it is atomized by the pressure of another stream of compressed air. The atomized coating particles enter the electromagnetic field and acquire a negative charge, forming coating particles 5 to be negatively charged. These particles then directionally fly to the positively charged end face of the steel coil, exposing the exposed metal surface; that is, in... Figure 1 The left end face of the decarburized annealed steel coil 7, which is placed on the steel coil support 6, is sprayed.

[0038] (5) In the above electrostatic spraying method, the compressed air control system controls the output compressed air pressure to be 0.1 to 1 MPa. If the pressure is too low, the release agent coating cannot be atomized; if the pressure is too high, the electric field will be destroyed, and the control will be unstable.

[0039] (6) In the above electrostatic spraying method, the input voltage of electrostatic spraying is 220V AC, the output DC voltage is 8-12V, and the working current is generally 50-200mA.

[0040] (7) In the above electrostatic spraying method, the distance between the spray gun and the end face of the steel coil directly affects the electric field strength, and the distance range is 10 to 50 cm.

[0041] (8) In the above electrostatic spraying method, the mass ratio of release agent to water is between 1:5 and 1:10.

[0042] In the above electrostatic spraying method, the mass percentage of each component of the release agent is: magnesium oxide powder 75-94.5%, calcium oxide powder 5-20%, and antimony sulfate 0.5-5%.

[0043] The innovation of this invention lies in the addition of a certain proportion of calcium oxide and antimony sulfate to the electrostatic spraying release agent compared to conventional release agents. The high calcium oxide content increases the hydration rate of magnesium oxide, resulting in strong water absorption. If conventional release agents are used for full-surface coating, moisture in the steel coil cannot be removed during high-temperature annealing, necessitating minimizing the amount of calcium oxide. However, when applied as a secondary spraying of the edge release agent on the strip end face, it does not affect moisture removal from the steel coil, resulting in a thicker magnesium silicate underlayer pinning structure at the edge, providing better isolation and reducing the rate of adhesion. Antimony is a surface-active and segregating element, capable of segregating on free surfaces and at grain boundaries. Adding antimony sulfate to the edge release agent can, on the one hand, improve the stability of the glass film and reduce the rate of adhesion; on the other hand, it suppresses the secondary grain size at the edge, reducing the hardness and brittleness of the strip at the edge after high-temperature annealing. Even if adhesion occurs, the adhesion points are easily detached during uncoiling, preventing it from extending into the middle of the strip and causing significant impact.

[0044] (9) In the above electrostatic spraying method, the particle size of magnesium oxide powder and calcium oxide powder is between 1 μm and 10 μm. The appropriate particle size ensures that the release agent can enter the gap between the layers on the end face of the steel plate and be deposited.

[0045] (10) The above-mentioned high-temperature annealing can be carried out using the conventional high-temperature annealing process of oriented electrical steel, which includes raising the annealing temperature to above 1100°C in a mixed atmosphere of nitrogen and hydrogen, and after completing the secondary recrystallization, uniformly heating at above 1150°C for at least 20 hours in a reducing atmosphere with a hydrogen content of above 50%.

[0046] (11) Finally, the unreacted components remaining on the surface of the high-temperature annealed steel sheet are removed by acid solution, and then a conventional insulating coating containing phosphate and colloidal silica is applied and hot stretching and flattening annealing is performed to obtain an oriented electrical steel sheet with through-plate performance.

[0047] The specific embodiments of the present invention will be further described in detail below through specific examples.

[0048] A steel billet containing 3.35 wt% Si, 0.046 wt% C, 0.11 wt% Mn, 0.005 wt% S, 0.030 wt% Al, 0.0065 wt% N, with the balance being Fe and unavoidable impurities, was reheated at 1215 °C, then hot-rolled and annealed at 1150 °C and pickled. It was subsequently rolled to 0.22 mm using a single-stand mill. Decarburization annealing was performed at 850 °C in a humid nitrogen and hydrogen atmosphere at 60 °C, followed by MgO coating and drying before coiling. The release agent volume ratio k after coiling was controlled to be 0.09–0.10. The release agent was a mixture of 90% magnesium oxide, 8% calcium oxide, and 2% antimony sulfate by mass percentage. The release agent was applied twice to the end faces of the steel coil using an electrostatic spraying device as shown in the attached diagram. After spraying, the steel coils are heated to 1200℃ in a ring furnace under a 25% N2 + 75% H2 atmosphere, and then held at that temperature for 24 hours under a 100% H2 atmosphere before cooling. After high-temperature annealing, the surface of the steel sheet is treated, then uncoiled in a hot stretching unit, coated with an insulating coating, and leveled and annealed to obtain the finished product.

[0049] In Table 1 below, numbers 1-10 are examples, and numbers 11-20 are comparative examples.

[0050] Table 1:

[0051]

[0052]

[0053] As shown in Table 1, Examples 1 to 10, which employ the method described in this invention, effectively prevent steel coil adhesion. However, in Comparative Examples 11 to 15, adhesion may occur on the uncoated end face when only one end face is coated. Furthermore, adhesion cannot be effectively prevented when the particle size in Comparative Example 16 is not up to standard, when the magnesium oxide ratio in Comparative Example 17 is too high, or when the voltage strength or coating distance in Comparative Examples 18 to 20 does not meet the requirements, resulting in a poor coating effect.

[0054] This invention provides a method for manufacturing thin-gauge grain-oriented electrical steel sheets, differing from conventional methods. Based on conventional grain-oriented electrical steel sheet manufacturing processes, a secondary atomized electrostatic isolating agent is applied to the end face of the steel coil after decarburization annealing. This precisely covers the exposed charged metal areas at the outermost edge of the coil. High-temperature annealing then allows the secondary isolating agent to react with the strip steel, forming a glass film underlayer. This effectively isolates direct contact between layers at the strip steel edges, preventing adhesion during high-temperature annealing that could affect subsequent uncoiling processes. Considering the excellent through-sheet properties of the steel sheets manufactured using this method, this invention has broad application prospects.

[0055] Although the preferred embodiments of the invention have been described and illustrated above, it should not be construed as limiting the invention to these embodiments. Those skilled in the art will understand that various modifications and variations can be made within the scope described above without departing from the spirit and scope defined by the claims.

Claims

1. A method for manufacturing a thin-gauge oriented electrical steel sheet with excellent through-sheet properties, comprising the following steps: hot-rolling a heated steel billet; annealing a hot-rolled steel sheet; cold-rolling an annealed steel sheet to a target thickness; decarburizing and annealing a cold-rolled steel sheet; coating with a release agent and drying and coiling; performing a secondary spraying of the release agent on the end face of the steel coil; subjecting the resulting steel sheet to high-temperature annealing for secondary recrystallization; performing leveling annealing and coating with an insulating coating; Its features are, When applying the release agent and drying and winding, the release agent thickness should be controlled at 10-15 g / m. 2 During the winding process, the winding tension is controlled within the range of 50-100 N / m. 2 The separating agent, by mass percentage, comprises the following components: 75-94.5% magnesium oxide powder, 5-20% calcium oxide powder, and 0.5-5% antimony sulfate. The release agent is applied in a second coat using an atomized electrostatic spraying method. The volume ratio k of the release agent after coiling is controlled to be 0.05–0.15; the formula for calculating the volume ratio k is as follows: k=m / (Π(R 2 -r 2 )×w×ρ 硅钢 ); Where m is the weighing weight of the coiled steel, Π is a constant, R is the outer diameter of the coiled steel, r is the inner diameter of the coiled steel, w is the strip width, and ρ 硅钢 The density of silicon steel is taken as 7.85 kg / dm³. 3 .

2. The method for manufacturing a thin-gauge oriented electrical steel sheet with excellent through-sheet properties according to claim 1, characterized in that, The particle size of magnesium oxide powder and calcium oxide powder is between 1μm and 10μm.

3. The method for manufacturing a thin-gauge oriented electrical steel sheet with excellent through-sheet properties according to claim 1, characterized in that, The steel plate to be coated contains 2.0 to 4.5 wt% silicon.

4. The method for manufacturing a thin-gauge oriented electrical steel sheet with excellent through-sheet properties according to claim 3, characterized in that, The steel plate to be coated also contains 0.035–0.120 wt% C, 0.05–0.20 wt% Mn, 0.002–0.012 wt% S, 0.015–0.035 wt% Als, 0.001–0.010 wt% N, and the balance Fe and unavoidable impurities.

5. The method for manufacturing a thin-gauge oriented electrical steel sheet with excellent through-sheet properties according to claim 1, characterized in that, Before hot rolling, the steel billet is heated in a temperature range below 1380℃ and hot-rolled to obtain a hot-rolled steel plate of 2.0 to 3.0 mm; then it is hot-rolled and annealed at 1000 to 1150℃, and then pickled and cold-rolled to obtain a cold-rolled steel plate of 0.15 to 0.35 mm thickness; then it is decarburized and annealed in a humid atmosphere containing hydrogen and nitrogen at a temperature range of 800 to 900℃ to obtain a steel plate.

6. The method for manufacturing a thin-gauge oriented electrical steel sheet with excellent through-sheet properties according to claim 1 or 5, characterized in that, When the obtained steel sheet is subjected to high-temperature annealing for secondary recrystallization, the annealing temperature is raised to above 1100°C in a mixed atmosphere of nitrogen and hydrogen, and after the secondary recrystallization is completed, it is uniformly heated at above 1150°C for at least 20 hours in a reducing atmosphere with a hydrogen content of more than 50%.

7. The method for manufacturing a thin-gauge oriented electrical steel sheet with excellent through-sheet properties according to claim 1, characterized in that, A second spraying of the release agent is performed, causing the atomized release agent coating particles to acquire a negative charge in a DC high-voltage electric field. Under the influence of the electrostatic field, they flow directionally towards the exposed edge of the strip steel on the end face of the decarburized annealed steel coil, neutralizing and depositing into a uniform and firmly adhered film.

8. The method for manufacturing a thin-gauge oriented electrical steel sheet with excellent through-sheet properties according to claim 7, characterized in that, The electrostatic spraying method includes a spray gun connected to a compressed air control system. The spray gun is connected to the negative terminal of a high-frequency, high-voltage direct current, and the steel coil is connected to the positive terminal. The paint is sent to the spray gun by compressed air and atomized in the spray gun with the help of another compressed air pressure. The atomized paint particles enter the electromagnetic field, become negatively charged, and then fly directionally to the positively charged end face of the steel coil.

9. The method for manufacturing a thin-gauge oriented electrical steel sheet with excellent through-sheet properties according to claim 8, characterized in that, The compressed air control system controls the output compressed air pressure to be 0.1-1 MPa; the output DC voltage to be 8-12V; the operating current to be 50-200mA; and the distance between the spray gun and the end face of the steel coil to be 10-50cm.

10. The method for manufacturing a thin-gauge oriented electrical steel sheet with excellent through-sheet properties according to claim 7, characterized in that, When applying the second coat, the ratio of release agent to water should be 1:5 to 1:10.

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