A low core loss non-oriented silicon steel and a production method thereof

Abstract

This invention discloses a low-iron-loss non-oriented silicon steel and its production method, relating to the field of steel smelting technology. After the cold rolling process, the steel plate surface is laser shot-peened to create an activation state conducive to subsequent silicon diffusion. Surface cleaning removes oil, oxides, and residual impurities, providing a clean and stable reaction base for chemical vapor deposition (CVD) silicon diffusion. Subsequently, CVD silicon diffusion is performed in a silicon-containing atmosphere, enriching silicon on the steel plate surface and diffusing it into the matrix, forming a high-silicon gradient diffusion layer from the surface inwards. This increases the surface resistivity of the material, suppresses eddy current losses, and avoids excessively high overall silicon content that could affect processing performance. Finally, recrystallization annealing is performed under a DC magnetic field to improve the material's magnetic properties and reduce energy loss during magnetization. Through the above process combination, this invention achieves reduced iron loss and improved magnetic flux density while maintaining the processing performance of non-oriented silicon steel.

Description

Technical Field

[0001] This invention relates to the field of iron and steel smelting technology, specifically to a low-iron-loss non-oriented silicon steel and its production method. Background Technology

[0002] Currently, non-oriented silicon steel, as the core soft magnetic material for various motor cores, is facing increasingly stringent energy efficiency requirements from fields such as new energy vehicles and high-end intelligent manufacturing. However, existing manufacturing technologies still present many irreconcilable contradictions. Traditional processes typically rely on increasing the silicon content of the matrix to reduce iron loss, but this directly leads to a sharp deterioration in the material's plasticity, causing the risk of strip breakage during cold rolling and difficulties in subsequent lamination processing, severely restricting the yield and production efficiency of high-grade products.

[0003] Meanwhile, conventional silicon infiltration technology cannot solve the problem of weak interfacial bonding. Significant compositional abrupt changes and micro-cracks are easily formed between the infiltrated layer and the substrate. Under alternating magnetic fields, it not only fails to effectively block eddy currents, but also exacerbates core vibration and noise due to the mismatch of magnetostriction coefficients.

[0004] Furthermore, existing annealing processes lack effective means to control grain orientation. During recrystallization, grain growth is random, with a high proportion of grains in the less magnetizable direction, leading to increased resistance to magnetization reversal and severe energy dissipation. Material performance improvements have reached a bottleneck, making it difficult to simultaneously meet the comprehensive requirements of low iron loss, high magnetic induction, and good machinability, significantly limiting the design and application of high-performance motor cores. Summary of the Invention

[0005] The purpose of this invention is to provide a low-iron-loss non-oriented silicon steel and its production method, so as to solve the problems existing in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for producing low-iron-loss non-oriented silicon steel, comprising the following steps: (1) Laser shot peening is performed on the cold-rolled substrate; (2) The substrate after laser shot peening is then surface-cleaned; (3) The purified substrate is subjected to chemical vapor deposition silicon infiltration treatment in a silicon-containing atmosphere; (4) Under the assistance of a DC magnetic field, the substrate after silicon diffusion treatment is recrystallized and annealed to obtain low iron loss non-oriented silicon steel.

[0007] Furthermore, in step (1), the cold-rolled substrate is prepared from non-oriented silicon steel substrate through smelting, continuous casting, hot rolling, normalizing, pickling and one cold rolling.

[0008] Furthermore, the non-oriented silicon steel substrate comprises, by mass percentage: C≤0.0030%, Si 2.80%~3.50%, Als 0.50%~1.20%, Mn 0.20%~0.80%, S≤0.0020%, P≤0.020%, N≤0.0020%, Ti≤0.0020%, with the balance being Fe and unavoidable impurities.

[0009] Furthermore, the hot rolling process involves heating the slab produced by smelting and continuous casting of molten steel to 1080℃~1200℃ and holding it at that temperature before hot rolling to obtain a hot-rolled plate with a thickness of 2.0mm~2.5mm. The normalizing temperature is 850℃~970℃, the holding time is 2min~5min, and the plate is air-cooled to room temperature.

[0010] Furthermore, the cold rolling is performed using a single cold rolling method to achieve a finished product thickness of 0.20 mm to 0.35 mm.

[0011] Furthermore, the parameters for laser shot peening in step (1) are: laser wavelength of 1064 nm, pulse width of 10 ns to 20 ns, and power density of 3 GW / cm². 2 ~5 GW / cm 2 The overlap rate of the light spot is 50% to 70%, and deionized water is used as the constraint layer.

[0012] Furthermore, in step (2), surface purification is carried out by heating in a mixed protective atmosphere of hydrogen and nitrogen, with hydrogen accounting for 30% to 50% of the volume, heating temperature of 400℃ to 600℃, dew point controlled below -40℃, and heat preservation time of 3 min to 5 min.

[0013] Furthermore, in step (3), the chemical vapor deposition silicon infiltration process uses silane or silane as the silicon source gas and hydrogen as the carrier gas and dilution gas. The volumetric flow rate ratio of the silicon source gas to hydrogen is 1:5 to 1:10, and the flow rate of the mixed gas is 20 to 30 L / h. This flow rate range can maintain a stable flow field and silicon source partial pressure while ensuring that the reaction gas fully covers the substrate surface, avoiding flow field disturbance and increased energy consumption caused by excessive gas flow rate. The deposition temperature is 500℃ to 650℃, the deposition time is 2 to 16 min, and then the temperature is raised to 760 to 800℃ under an argon atmosphere and held for 4 to 7 h to form a high silicon gradient infiltration layer on the substrate surface. This gradient infiltration layer can significantly alleviate the abrupt change in silicon content between the surface and the substrate, improve the surface resistivity, suppress high-frequency eddy current loss, and avoid the overall silicon content being too high, which would lead to deterioration of the substrate plasticity.

[0014] Furthermore, in step (4), the recrystallization annealing process is carried out at a temperature of 950℃~1050℃ and a holding time of 60s~180s. The intensity of the DC magnetic field is 0.5~1.5T and the magnetic field direction is parallel to or perpendicular to the rolling direction.

[0015] Furthermore, this includes low-iron-loss non-oriented silicon steel prepared by the above method.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are: (1) After the cold rolling process is completed, the steel plate surface is treated by laser shot peening technology to make the substrate surface form an activated state that is conducive to the subsequent silicon diffusion reaction, thereby improving the surface layer’s ability to receive and diffuse silicon. Then, the oil, oxides and other residual impurities on the steel plate surface are removed by surface cleaning treatment to ensure that the substrate surface is clean and stable before silicon diffusion, providing a good reaction basis for subsequent chemical vapor deposition silicon diffusion. (2) In this invention, the purified substrate is subjected to chemical vapor deposition silicon infiltration treatment in a silicon-containing atmosphere, so that silicon elements are gradually enriched on the surface of the steel plate and diffuse into the interior of the substrate, forming a high silicon gradient infiltration layer from the surface to the interior. This gradient infiltration layer can alleviate the abrupt change in composition between the surface and the substrate, enhance the bonding stability between the silicon infiltration layer and the substrate, and improve the surface resistivity of the material and suppress eddy current loss, while avoiding the significant decrease in material processing plasticity caused by excessively high overall silicon content; (3) The present invention performs recrystallization annealing under the assistance of DC magnetic field. By applying an external magnetic field, the magnetic properties of the material can be improved, the energy loss during the magnetization process can be reduced, and thus the hysteresis loss can be reduced. At the same time, the surface high silicon region combined with the surface strengthening effect brought about by laser shot peening helps to reduce the additional loss during the operation of the iron core. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The test methods for various indicators of the low-iron-loss non-oriented silicon steel produced in the following embodiments are as follows: Magnetic property testing: Using the same specifications of the example and comparative sample, according to GB / T 3655-2008 "Method for measuring the magnetic properties of electrical steel sheets (strips) using Epstein squares", the iron loss value P1.5 / 50 under the condition of 50Hz frequency and magnetic flux density of 1.5T, and the magnetic induction intensity B50 under the condition of magnetic field strength of 5000A / m were tested.

[0019] Average grain size test: Samples of the same specifications from the example and comparative examples were ground, polished, and etched with nitric acid and alcohol. The microstructure was observed using a metallographic microscope, and the average grain size of the samples was statistically analyzed by the cross-section method.

[0020] Mechanical property testing: Take the same specifications of the example and comparative specimens, and test the tensile strength and elongation after fracture of the specimens in accordance with GB / T 228.1-2010 "Metallic materials - Tensile testing - Part 1: Test method at room temperature" to evaluate the processing and forming performance of the material.

[0021] Example 1 A low-iron-loss non-oriented silicon steel, the base material of which comprises, by weight percentage: C 0.0028%, Si 2.80%, Als 0.50%, Mn 0.20%, S 0.0018%, P 0.018%, N 0.0018%, Ti 0.0018%, with the balance being Fe and unavoidable impurities.

[0022] Its preparation method includes the following steps: (1) The molten steel substrate is smelted in a converter and refined in RH vacuum, and then continuously cast into a slab. The slab is heated to 1080℃ and held for heat treatment before hot rolling to obtain a hot-rolled plate with a thickness of 2.0 mm. (2) The hot-rolled plate is subjected to normalizing treatment at a temperature of 850°C and a holding time of 5 min, and then air-cooled to room temperature; (3) Pickling is performed on the normalized hot-rolled plate to remove the oxide scale, and then the plate is rolled to a finished thickness of 0.20 mm by one cold rolling process to obtain a cold-rolled substrate; (4) The cold-rolled substrate is subjected to laser shot peening with a laser wavelength of 1064 nm, a pulse width of 10 ns, and a power density of 3 GW / cm². 2 The light spot overlap rate is 50%, and deionized water is used as a constraint layer; (5) The substrate after laser shot peening is cleaned and heated in a mixed protective atmosphere of hydrogen and nitrogen, with hydrogen accounting for 30% of the volume, the heating temperature being 400℃, the dew point being controlled at -45℃, and the holding time being 5 min. (6) In a silicon-containing atmosphere, the purified substrate is subjected to chemical vapor deposition silicon infiltration treatment. Silane is used as the silicon source gas, and hydrogen is used as the carrier gas and dilution gas. The volume flow ratio of silicon source gas to hydrogen is 1:5, the flow rate of the mixed gas is 20L / h, the deposition temperature is 500℃, the deposition time is 2min, and then in an argon atmosphere, the temperature is raised to 760℃ and held for 4h. (7) Under the assistance of a DC magnetic field with an intensity of 0.5T and the direction of the magnetic field being parallel to the rolling direction, the substrate after silicon diffusion treatment is recrystallized and annealed to obtain low iron loss non-oriented silicon steel. The recrystallization annealing process is carried out at a temperature of 950℃ and a holding time of 180s.

[0023] Example 2 A low-iron-loss non-oriented silicon steel, the base material of which comprises, by weight percentage: C 0.0020%, Si 3.00%, Als 0.80%, Mn 0.40%, S 0.0010%, P 0.010%, N 0.0010%, Ti 0.0010%, with the balance being Fe and unavoidable impurities.

[0024] Its preparation method includes the following steps: (1) The molten steel substrate is smelted in a converter and refined in RH vacuum, and then continuously cast into a slab. The slab is heated to 1120℃ and held for heat treatment before hot rolling to obtain a hot-rolled plate with a thickness of 2.2 mm. (2) The hot-rolled plate is normalized at a temperature of 900°C for 3.5 min and then air-cooled to room temperature. (3) Pickling is performed on the normalized hot-rolled plate to remove the oxide scale, and then the plate is rolled to a finished thickness of 0.25 mm by one cold rolling process to obtain a cold-rolled substrate; (4) The cold-rolled substrate is subjected to laser shot peening with a laser wavelength of 1064 nm, a pulse width of 13 ns, and a power density of 3.5 GW / cm². 2 The light spot overlap rate is 55%, and deionized water is used as a constraint layer; (5) The substrate after laser shot peening is cleaned and heated in a mixed protective atmosphere of hydrogen and nitrogen, with hydrogen accounting for 35% of the volume, the heating temperature being 450℃, the dew point being controlled at -42℃, and the holding time being 4 min. (6) Under a silicon-containing atmosphere, the purified substrate is subjected to chemical vapor deposition silicon infiltration treatment. Ethylsilane is used as the silicon source gas, and hydrogen is used as the carrier gas and dilution gas. The volume flow ratio of silicon source gas to hydrogen is 1:6, and the flow rate of the mixed gas is 22L / h. The deposition temperature is 550℃, the deposition time is 5min, and then under an argon atmosphere, the temperature is raised to 770℃ and held for 5h. (7) Under the assistance of a DC magnetic field with an intensity of 0.8T and the direction of the magnetic field perpendicular to the rolling direction, the substrate after silicon diffusion treatment is recrystallized and annealed to obtain low iron loss non-oriented silicon steel. The recrystallization annealing process is carried out at a temperature of 980℃ and a holding time of 120 s.

[0025] Example 3 A low-iron-loss non-oriented silicon steel, the base material of which comprises, by weight percentage: C 0.0015%, Si 3.15%, Als 0.85%, Mn 0.50%, S 0.0012%, P 0.012%, N 0.0012%, Ti 0.0012%, with the balance being Fe and unavoidable impurities.

[0026] Its preparation method includes the following steps: (1) The molten steel substrate is smelted in a converter and refined in RH vacuum, and then continuously cast into a slab. The slab is heated to 1150℃ and held for heat treatment before hot rolling to obtain a hot-rolled plate with a thickness of 2.3 mm. (2) The hot-rolled plate is normalized at a temperature of 920°C for 3 minutes and then air-cooled to room temperature. (3) Pickling is performed on the normalized hot-rolled plate to remove the oxide scale, and then the plate is rolled to a finished thickness of 0.28 mm by one cold rolling process to obtain a cold-rolled substrate; (4) The cold-rolled substrate is subjected to laser shot peening with a laser wavelength of 1064 nm, a pulse width of 15 ns, and a power density of 4 GW / cm². 2 The light spot overlap rate is 60%, and deionized water is used as a constraint layer; (5) The substrate after laser shot peening is cleaned and heated in a mixed protective atmosphere of hydrogen and nitrogen, with hydrogen accounting for 40% of the volume, the heating temperature being 500℃, the dew point being controlled at -43℃, and the holding time being 4 min. (6) In a silicon-containing atmosphere, the purified substrate is subjected to chemical vapor deposition silicon infiltration treatment. Silane is used as the silicon source gas, and hydrogen is used as the carrier gas and dilution gas. The volume flow ratio of silicon source gas to hydrogen is 1:7, the flow rate of the mixed gas is 25L / h, the deposition temperature is 580℃, the deposition time is 10min, and then in an argon atmosphere, the temperature is raised to 780℃ and held for 6h. (7) Under the assistance of a DC magnetic field with a strength of 1T and the direction of the magnetic field parallel to the rolling direction, the substrate after silicon diffusion treatment is recrystallized and annealed to obtain low iron loss non-oriented silicon steel. The temperature of the recrystallization annealing process is 1000℃ and the holding time is 100 s.

[0027] Example 4 A low-iron-loss non-oriented silicon steel, the base material of which comprises, by weight percentage: C 0.0010%, Si 3.30%, Als 1.00%, Mn 0.60%, S 0.0015%, P 0.015%, N 0.0015%, Ti 0.0015%, with the balance being Fe and unavoidable impurities.

[0028] Its preparation method includes the following steps: (1) The molten steel substrate is smelted in a converter and refined in RH vacuum, and then continuously cast into a slab. The slab is heated to 1180℃ and held for heat treatment before hot rolling to obtain a hot-rolled plate with a thickness of 2.4 mm. (2) The hot-rolled plate is normalized at a temperature of 950°C for 2.5 min and then air-cooled to room temperature. (3) Pickling is performed on the normalized hot-rolled plate to remove the oxide scale, and then the plate is rolled to a finished thickness of 0.32 mm by one cold rolling process to obtain a cold-rolled substrate; (4) The cold-rolled substrate is subjected to laser shot peening with a laser wavelength of 1064 nm, a pulse width of 18 ns, and a power density of 4.5 GW / cm². 2 The light spot overlap rate is 65%, and deionized water is used as a constraint layer; (5) The substrate after laser shot peening is cleaned and heated in a mixed protective atmosphere of hydrogen and nitrogen, with hydrogen accounting for 45% of the volume, the heating temperature being 550℃, the dew point being controlled at -44℃, and the holding time being 3.5 min. (6) In a silicon-containing atmosphere, the purified substrate is subjected to chemical vapor deposition silicon infiltration treatment. Ethylsilane is used as silicon source gas, and hydrogen is used as carrier gas and dilution gas. The volume flow ratio of silicon source gas to hydrogen is 1:9, the flow rate of mixed gas is 28L / h, the deposition temperature is 620℃, the deposition time is 13min, and then in an argon atmosphere, the temperature is raised to 790℃ and held for 6.5h. (7) Under the assistance of a DC magnetic field with an intensity of 1.2T and the direction of the magnetic field perpendicular to the rolling direction, the substrate after silicon diffusion treatment is recrystallized and annealed to obtain low iron loss non-oriented silicon steel. The recrystallization annealing process is carried out at a temperature of 1020℃ and a holding time of 80s.

[0029] Example 5 A low-iron-loss non-oriented silicon steel, the base material of which comprises, by weight percentage: C 0.0010%, Si 3.50%, Als 1.20%, Mn 0.80%, S 0.0020%, P 0.020%, N 0.0020%, Ti 0.0020%, with the balance being Fe and unavoidable impurities.

[0030] Its preparation method includes the following steps: (1) The molten steel substrate is smelted in a converter and refined in RH vacuum, and then continuously cast into a slab. The slab is heated to 1200℃ and held for heat treatment before hot rolling to obtain a hot-rolled plate with a thickness of 2.5mm. (2) The hot-rolled plate is normalized at a temperature of 970°C for 2 minutes and then air-cooled to room temperature. (3) Pickling is performed on the normalized hot-rolled plate to remove the oxide scale, and then the plate is rolled to a finished thickness of 0.35 mm by one cold rolling process to obtain a cold-rolled substrate; (4) The cold-rolled substrate is subjected to laser shot peening with a laser wavelength of 1064 nm, a pulse width of 20 ns, and a power density of 5 GW / cm². 2 The light spot overlap rate is 70%, and deionized water is used as a constraint layer; (5) The substrate after laser shot peening is surface cleaned and heated in a mixed protective atmosphere of hydrogen and nitrogen, with hydrogen accounting for 50% of the volume, heating temperature of 600℃, dew point controlled at -41℃, and holding time of 3min. (6) In a silicon-containing atmosphere, the purified substrate is subjected to chemical vapor deposition silicon infiltration treatment. Silane is used as the silicon source gas, and hydrogen is used as the carrier gas and dilution gas. The volume flow ratio of silicon source gas to hydrogen is 1:10, the flow rate of the mixed gas is 30L / h, the deposition temperature is 650℃, the deposition time is 16min, and then in an argon atmosphere, the temperature is raised to 800℃ and held for 7h. (7) Under the assistance of a DC magnetic field with an intensity of 1.3 T and the direction of the magnetic field being parallel to the rolling direction, the substrate after silicon diffusion treatment is recrystallized and annealed to obtain low iron loss non-oriented silicon steel. The recrystallization annealing process is carried out at a temperature of 1050℃ and a holding time of 60s.

[0031] Comparative Example 1 The difference between Comparative Example 1 and Example 3 is that step (4) is omitted, and step (5) is changed to: directly cleaning the surface of the cold-rolled substrate; the remaining steps are the same as in Example 3.

[0032] Comparative Example 2 The difference between Comparative Example 2 and Example 3 is that step (6) is omitted, and step (7) is changed to: the substrate after laser shot peening is directly subjected to recrystallization annealing; the remaining steps are the same as in Example 3.

[0033] Comparative Example 3 The difference between Comparative Example 3 and Example 3 lies in step (7). Step (7) is changed to not applying a DC magnetic field and only performing conventional recrystallization annealing; the remaining steps are the same as in Example 3.

[0034] Comparative Example 4 The difference between Comparative Example 4 and Example 3 lies in step (6). Step (6) is changed to: chemical vapor deposition silicon infiltration treatment is performed on the purified substrate under a silicon-containing atmosphere. Silane is used as the silicon source gas, and hydrogen is used as the carrier gas and dilution gas. The volume flow ratio of silicon source gas to hydrogen is 1:7, the flow rate of the mixed gas is 25L / h, the deposition temperature is 580℃, and the deposition time is 10min. The remaining steps are the same as in Example 3.

[0035] Comparative Example 5 The difference between Comparative Example 5 and Example 3 is that the laser peening parameters in step (4) were adjusted, and the power density was set to 1 GW / cm². 2 (Below the lower limit of the claim), the spot overlap rate is set to 30%; the remaining steps are the same as in Example 3.

[0036] Example of effect Table 1 below presents the performance analysis results of low-iron-loss non-oriented silicon steels produced by Examples 1 to 5 and Comparative Examples 1 to 5 of the present invention.

[0037] Table 1 Comparison of experimental data from the examples and comparative examples reveals that (1) after the cold rolling process is completed, the present invention uses laser shot peening technology to treat the surface of the steel plate, so that the substrate surface forms an activated state that is conducive to the subsequent silicon diffusion reaction, thereby improving the surface layer's ability to receive and diffuse silicon elements; subsequently, surface cleaning treatment is used to remove oil stains, oxides and other residual impurities from the surface of the steel plate, ensuring that the substrate surface is clean and stable before silicon diffusion, providing a good reaction basis for subsequent chemical vapor deposition silicon diffusion. (2) In this invention, the purified substrate is subjected to chemical vapor deposition silicon infiltration treatment in a silicon-containing atmosphere, so that silicon elements are gradually enriched on the surface of the steel plate and diffuse into the interior of the substrate, forming a high silicon gradient infiltration layer from the surface to the interior. This gradient infiltration layer can alleviate the abrupt change in composition between the surface and the substrate, enhance the bonding stability between the silicon infiltration layer and the substrate, and improve the surface resistivity of the material and suppress eddy current loss, while avoiding the significant decrease in material processing plasticity caused by excessively high overall silicon content; (3) The present invention performs recrystallization annealing under the assistance of DC magnetic field. By applying an external magnetic field, the magnetic properties of the material can be improved, the energy loss during the magnetization process can be reduced, and thus the hysteresis loss can be reduced. At the same time, the surface high silicon region combined with the surface strengthening effect brought about by laser shot peening helps to reduce the additional loss during the operation of the iron core.

[0038] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for producing low-iron-loss non-oriented silicon steel, characterized in that, Includes the following steps: (1) Laser shot peening is performed on the cold-rolled substrate; (2) The substrate after laser shot peening is then surface-cleaned; (3) The purified substrate is subjected to chemical vapor deposition silicon infiltration treatment in a silicon-containing atmosphere; (4) Under the assistance of a DC magnetic field, the substrate after silicon diffusion treatment is recrystallized and annealed to obtain low iron loss non-oriented silicon steel.

2. The method for producing low-iron-loss non-oriented silicon steel according to claim 1, characterized in that, In step (1), the cold-rolled substrate is prepared from non-oriented silicon steel substrate through smelting, continuous casting, hot rolling, normalizing, pickling and one cold rolling.

3. The method for producing low-iron-loss non-oriented silicon steel according to claim 2, characterized in that, The non-oriented silicon steel substrate contains, by mass percentage: C≤0.0030%, Si 2.80%~3.50%, Als 0.50%~1.20%, Mn 0.20%~0.80%, S≤0.0020%, P≤0.020%, N≤0.0020%, Ti≤0.0020%, with the balance being Fe and unavoidable impurities.

4. The method for producing low-iron-loss non-oriented silicon steel according to claim 2, characterized in that, The hot rolling process involves heating slabs made from molten steel through smelting and continuous casting to 1080℃~1200℃ and holding them at that temperature before hot rolling to obtain hot-rolled plates with a thickness of 2.0mm~2.5mm. The normalizing temperature is 850℃~970℃, the holding time is 2min~5min, and the plates are then air-cooled to room temperature.

5. The method for producing low-iron-loss non-oriented silicon steel according to claim 2, characterized in that, The cold rolling process involves rolling the product to a thickness of 0.20 mm to 0.35 mm using a single cold rolling method.

6. The method for producing low-iron-loss non-oriented silicon steel according to claim 1, characterized in that, The parameters for laser shot peening in step (1) are: laser wavelength of 1064 nm, pulse width of 10 ns to 20 ns, and power density of 3 GW / cm². 2 ~5 GW / cm 2 The overlap rate of the light spot is 50% to 70%, and deionized water is used as the constraint layer.

7. The method for producing low-iron-loss non-oriented silicon steel according to claim 1, characterized in that, In step (2), surface purification is carried out by heating in a mixed protective atmosphere of hydrogen and nitrogen, with hydrogen accounting for 30% to 50% of the volume, heating temperature of 400℃ to 600℃, dew point controlled below -40℃, and heat preservation time of 3 min to 5 min.

8. The method for producing low-iron-loss non-oriented silicon steel according to claim 1, characterized in that, In step (3), the chemical vapor deposition silicon infiltration process uses silane or silane as the silicon source gas, and hydrogen as the carrier gas and dilution gas. The volume flow ratio of silicon source gas to hydrogen is 1:5 to 1:10, the flow rate of the mixed gas is 20 to 30 L / h, the deposition temperature is 500℃ to 650℃, the deposition time is 2 to 16 min, and then the temperature is raised to 760 to 800℃ under an argon atmosphere and held for 4 to 7 h.

9. The method for producing low-iron-loss non-oriented silicon steel according to claim 1, characterized in that, The recrystallization annealing process in step (4) is carried out at a temperature of 950℃ to 1050℃ and a holding time of 60s to 180s. The intensity of the DC magnetic field is 0.5 to 1.5T and the magnetic field direction is parallel to or perpendicular to the rolling direction.

10. A low-iron-loss non-oriented silicon steel, characterized in that, It is prepared by the production method described in any one of claims 1 to 9.

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