An annealing method for reducing the magnetic anisotropy of non-oriented silicon steel and product

Abstract

The application relates to an annealing method for weakening the magnetic anisotropy of non-oriented silicon steel and a product, and the method comprises the following steps: polishing the two ends and fixing the two ends on the two ends of a power supply; placing the fixed non-oriented silicon steel in a protective atmosphere; applying a pulse current with certain parameters to the non-oriented silicon steel through the power supply to anneal the non-oriented silicon steel, heating the non-oriented silicon steel to a certain temperature to perform high-temperature annealing for a period of time, and promoting the development of gamma texture and lambda texture of the non-oriented silicon steel; and air cooling the non-oriented silicon steel after the electric pulse high-temperature annealing to room temperature in the protective atmosphere. The electric pulse high-temperature annealing process shortens the annealing time of the non-oriented silicon steel, saves energy consumption, and improves the production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of electrical steel technology, specifically relating to an annealing method and product for reducing the magnetic anisotropy of non-oriented silicon steel. Background Technology

[0002] Cold-rolled non-oriented silicon steel is an important soft magnetic material for the cores of variable frequency motors, drive motors, and generators. Reducing its magnetic anisotropy is crucial. Motors, commonly used in industrial equipment, operate in a rotating state. Magnetic anisotropy represents the difference in magnetic properties of silicon steel in various directions, significantly impacting motor rotation and energy efficiency. If the non-oriented silicon steel used as the motor core has significant magnetic anisotropy, it will lead to uneven rotor stress, hindering high-speed, long-term motor operation, severely shortening motor life, and increasing maintenance costs. In recent years, motors have been developing towards automation and high speed, requiring motors with more uniform rotation and higher energy efficiency to meet future development demands. Therefore, there is a desire for non-oriented silicon steel with lower magnetic anisotropy.

[0003] Non-oriented silicon steel is a ferritic steel. Typically, the normal direction of the steel sheet is denoted by ND, the rolling direction by RD, and the transverse direction of the rolled sheet perpendicular to both ND and RD by TD. During recrystallization, due to grain nucleation and growth, the ferrite grains exhibit certain angles with each axis in the O-RD-TD-ND coordinate system. If a certain {hkl} plane of the grain is parallel to the rolling surface, a certain [unclear] plane on the {hkl} plane... <uvw>If the direction is parallel to the RD direction, then {hkl} can be used. <uvw>The orientation of a grain is expressed using the grain orientation. When a large number of grains in a polycrystalline material have the same or similar orientations, the polycrystalline material exhibits a texture phenomenon. In this case, the orientation of a representative grain can be used to represent the grain orientation. <uvw>This describes the texture of polycrystalline materials. The magnetic anisotropy of non-oriented silicon steel ultimately depends on the type and distribution of its texture. In commercially available non-oriented silicon steel, due to the presence of rolling texture, the finished sheet exhibits significant differences in magnetic properties between the rolling direction and the transverse direction, ultimately leading to substantial magnetic anisotropy. For silicon steel sheets used in stamping motor cores, planar magnetic isotropy is required for smooth motor rotation. Before leaving the factory, non-oriented silicon steel is required to have a transverse and longitudinal iron loss difference of ≤10%. Currently, the rejection rate of high-magnetic-induction non-oriented silicon steel produced by steel mills due to excessive magnetic anisotropy is approximately 3%. Because steel enterprises have a large production base, they ultimately generate a large amount of scrap steel, which does not meet the requirements for energy conservation and emission reduction in the steel industry.

[0004] Magnetocrystalline anisotropy is a property that exists on any {hkl} plane of an iron single crystal. <uvw>Directional magnetization energy consumption and <100> The difference in magnetization energy consumption between directions represents the energy consumed to reach the saturation magnetic induction intensity Bs under the action of an external magnetic field. h, k, l are crystal plane indices, and u, v, w are crystal direction indices. The average magnetocrystalline anisotropy values ​​of each {hkl} plane texture were calculated. The results show that the {111} plane texture (γ texture) has the highest magnetocrystalline anisotropy value, followed by {112} and {110}, with {100} (λ texture) having the lowest. This indicates that the λ texture has the best magnetic induction, while the γ texture is the worst. Summary of the Invention

[0005] To overcome the problem of high magnetic anisotropy of non-oriented silicon steel after traditional thermodynamic high-temperature annealing in existing technologies, this invention provides an annealing method and product for reducing the magnetic anisotropy of non-oriented silicon steel. It replaces traditional heat treatment annealing with electric pulse annealing, and reduces the magnetic anisotropy of non-oriented silicon steel by influencing the development of γ-texture and λ-texture in the transverse rolling direction, thereby solving the above-mentioned problems in the existing technology.

[0006] An annealing method for reducing the magnetic anisotropy of non-oriented silicon steel, the method comprising the steps of:

[0007] S1. After grinding both ends of the non-oriented silicon steel, it is fixed to both ends of the power supply;

[0008] S2. Place the fixed non-oriented silicon steel in a protective atmosphere;

[0009] S3. Annealing non-oriented silicon steel by applying a pulse current with certain parameters through a power supply, heating the non-oriented silicon steel to a certain temperature for a period of time to promote the increase of γ texture and λ texture of the non-oriented silicon steel.

[0010] S4. After high-temperature annealing by electric pulse, the non-oriented silicon steel is air-cooled to room temperature in a protective atmosphere.

[0011] In addition to the aspects and any possible implementations described above, a further implementation is provided, wherein the certain parameters include: pulse frequency of 500–2000 Hz, pulse width of 25–300 μs, duty cycle of 5–15%, pulse current direction at 0–90° to the rolling direction of the non-oriented silicon steel, and pulse current density of 40–100 A·mm. -2 .

[0012] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the pulse current frequency is 500Hz, the pulse width is 50µs, the current density is 50A / mm2, and a 240s current pulse high-temperature annealing process is performed.

[0013] In addition to the aspects described above and any possible implementation, a further implementation is provided in which the certain temperature is 750–1050°C and the holding time is 1–30 min.

[0014] In addition to the aspects described above and any possible implementation, an implementation is further provided in which the pulse current frequency is 1000Hz, the pulse width is 100µs, the current density is 60A / mm², and the duration is 150s.

[0015] The present invention also provides a non-oriented silicon steel, which is obtained by annealing. The microstructure of the non-oriented silicon steel is based on ferrite, with more γ texture in the rolling direction and more λ texture in the transverse direction.

[0016] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the chemical composition of the non-oriented silicon steel comprises, by mass percentage: C: 0.008–0.03%, Si: 1.80–3.20%, Mn: 0.05–0.50%, Al: 0.05–0.80%, P ≤ 0.050%, S ≤ 0.050%, with the remainder being Fe and unavoidable impurities.

[0017] As described above regarding the aspects and any possible implementations, a further implementation is provided, wherein the B of the non-oriented silicon steel... 50 The magnetic flux density is 1.55–1.73 T, and the magnetic anisotropy is 1–10%, of which B 50 The magnetic induction intensity value of non-oriented silicon steel under a magnetic field of 5000 A / m.

[0018] As described above regarding the aspects and any possible implementations, a further implementation is provided, wherein the P of the non-oriented silicon steel... 1.5 / 50 The iron loss is 2.5–4.5 W / kg, and the iron loss anisotropy is 1–10%, of which P 1.5 / 50 Tesla is the electrical energy consumed when a unit mass of non-oriented silicon steel is magnetized to a magnetic induction intensity of 1.5T under a 50Hz alternating magnetic field.

[0019] As described above regarding the aspects and any possible implementations, a further implementation is provided, wherein the P of the non-oriented silicon steel... 1.0 / 400 The iron loss is 25–35 W / kg, and the iron loss anisotropy is 1–10%, of which P 1.0 / 400 This refers to the electrical energy consumed when a unit mass of non-oriented silicon steel is magnetized to a magnetic induction intensity of 1.0T under a 400Hz alternating magnetic field.

[0020] Beneficial effects of the present invention

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention discloses an annealing method for weakly magnetically anisotropic non-oriented silicon steel. The method includes the following steps: grinding both ends and fixing them to the ends of a power source; placing the fixed non-oriented silicon steel in a protective atmosphere; annealing the non-oriented silicon steel by applying a pulsed current with certain parameters through the power source; heating the non-oriented silicon steel to a certain temperature for a period of time to promote the development of γ-texture and λ-texture; and air-cooling the non-oriented silicon steel after electrical pulse high-temperature annealing to room temperature in a protective atmosphere. This invention uses an electrical pulse high-temperature annealing process to shorten the annealing time of non-oriented silicon steel, save energy consumption, and improve production efficiency. Furthermore, electrical pulse treatment enables the steel plate to heat up rapidly at a heating rate of 300–500°C / min, shortening the heating time; under the same annealing temperature, electrical pulse promotes the development of the rolling-direction γ-texture and the transverse λ-texture, improving the uniformity of magnetic properties. This provides a new approach to reducing the magnetic anisotropy of non-oriented silicon steel, saving significant energy, reducing scrap rate, and meeting the green environmental protection requirements of steel enterprises. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the heat treatment process curves for Embodiment 1 and Comparative Example 2 of the present invention;

[0024] Figure 2 The heat treatment annealing and electric pulse annealing in Embodiment 1 and Comparative Example 2 of the present invention are B 50 Comparison diagram;

[0025] Figure 3 This is a flowchart of the method of the present invention. Detailed Implementation

[0026] To better understand the technical solution of this invention, the content of this invention includes, but is not limited to, the specific embodiments described below. Similar technologies and methods should be considered within the scope of protection of this invention. To make the technical problems to be solved, the technical solutions, and advantages of this invention clearer, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments.

[0027] It should be understood that the embodiments described in this invention are merely some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0028] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms "a," "the," and "the" as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0029] like Figure 3 As shown, the present invention provides an annealing method for reducing the magnetic anisotropy of non-oriented silicon steel, the method comprising the steps of:

[0030] S1. After grinding both ends of the non-oriented silicon steel, it is fixed to both ends of the power supply;

[0031] S2. Place the fixed non-oriented silicon steel in a protective atmosphere;

[0032] S3. Annealing non-oriented silicon steel by applying a pulse current with certain direction and parameters through a power source, so that the steel plate is heated rapidly at a heating rate of 300-500℃ / min.

[0033] S4. Heat the non-oriented silicon steel to a certain temperature and perform high-temperature annealing for a period of time to promote the increase of γ texture and λ texture of the non-oriented silicon steel;

[0034] S5. After high-temperature annealing by electric pulse, the non-oriented silicon steel is air-cooled to room temperature in a protective atmosphere.

[0035] Preferably, the specified parameters include: pulse frequency of 500–2000 Hz, pulse width of 25–300 μs, duty cycle of 5–15%, pulse current direction at 0–90° to the rolling direction of the non-oriented silicon steel, and pulse current density of 40–100 A·mm. -2 .

[0036] Preferably, the pulse current frequency is 500Hz, the pulse width is 50µs, and the current density is 50A / mm. 2 It undergoes a 240s current pulse high-temperature annealing process.

[0037] Preferably, the specific temperature is 750–1050℃, and the heat preservation time is 1–30 min.

[0038] Preferably, the pulse current has a frequency of 1000 Hz, a pulse width of 100 μs, and a current density of 60 A / mm². 2 Perform for 150 seconds.

[0039] Specifically, this invention employs current pulse annealing for high-temperature annealing. As a novel material microstructure modification technology, current pulse treatment significantly affects the microstructure, texture, magnetic properties, and mechanical properties of electrical steel. Under the same temperature conditions, current pulse annealing can promote the recrystallization process of non-oriented silicon steel, due to the roll-up γ-texture (…). <111> / / ND) is easily developed during recrystallization, thus ultimately increasing the strength of the γ texture and leading to a decrease in the rolling magnetic induction intensity. Experimental results show that pulsed annealing suppresses the transverse γ texture and develops the λ texture, resulting in an increase in the transverse magnetic induction intensity, which ultimately leads to a decrease in the difference between transverse and longitudinal iron losses, i.e., a decrease in magnetic anisotropy. The non-oriented silicon steel obtained by pulsed high-temperature annealing of the present invention has a magnetic anisotropy of 4.17% and an iron loss anisotropy of 12.97%; while the finished non-oriented silicon steel plate obtained by pulsed high-temperature annealing can reduce the magnetic anisotropy to 1.81% and the iron loss anisotropy to 3.9%.

[0040] This invention reduces the anisotropy of magnetic properties in non-oriented silicon steel by setting reasonable current parameters for the applied pulsed current, including current density, current direction, frequency, pulse width, and pulse time, through high-temperature annealing with electrical pulses. This affects the ratio of γ-texture to λ-texture in the transverse rolling direction, thereby reducing the magnetic anisotropy of the non-oriented silicon steel. The process of this invention is as follows:

[0041] (1) Fix the cold-rolled non-oriented silicon steel to both ends of the power supply and place it in a N2 protective atmosphere;

[0042] (2) High temperature annealing: High temperature annealing is carried out at 750-1050℃ for 1-30 minutes, and then air-cooled to room temperature.

[0043] In step (2), the high-temperature annealing of cold-rolled non-oriented silicon steel can be carried out by electric pulse treatment. During electric pulse treatment, the pulse frequency of the electric pulse is set to 500-2000Hz, the duty cycle is 5-15%, and the pulse current direction is 0-90° with the rolling direction. The temperature of the cold-rolled steel sheet under different current densities can be obtained from this. The non-oriented silicon steel is passed through an electric pulse with the above parameters, and the temperature rises under the action of the pulse current. The temperature of the non-oriented silicon steel is controlled by adjusting the electric pulse current density so that it can complete the corresponding heat treatment at the specified temperature. More γ texture is obtained in the rolling direction and more λ texture is obtained in the transverse direction, thereby reducing the magnetic property difference in the transverse rolling direction and reducing magnetic anisotropy.

[0044] As an embodiment of the present invention, the present invention also provides a non-oriented silicon steel finished plate prepared by the present invention, the microstructure of which is ferrite as the matrix, with more γ texture in the rolling direction and more λ texture in the transverse direction, B 50 The magnetic flux density is 1.55–1.73 T, the magnetic anisotropy is 1–10%, and the P value is... 1.5 / 50 The concentration is 2.5–4.5 W / kg, P 1.0 / 400 The iron loss is 25–35 W / kg, and the iron loss anisotropy is 1–10%.

[0045] The non-oriented silicon steel prepared by the above method according to the present invention mainly includes the following components by mass percentage: C: 0.008-0.03%, Si: 1.80-3.20%, Mn: 0.05-0.50%, Al: 0.05-0.80%, P≤0.050%, S≤0.050%, with the remainder being Fe and unavoidable impurities.

[0046] Unlike grain-oriented silicon steel, which requires two annealing processes to obtain the final product, non-oriented silicon steel only requires one annealing process to obtain the final finished sheet. Using electric pulse annealing instead of heat treatment annealing is easier to operate in the production of non-oriented silicon steel and has greater practical significance. Magnetic properties represent the ability of non-oriented silicon steel to conduct magnetism in a certain magnetization direction, while magnetic anisotropy represents the difference in magnetic properties of non-oriented silicon steel in the transverse rolling direction. Reducing magnetic anisotropy helps non-oriented silicon steel to have more uniform magnetic properties in different directions, which plays an important role in improving the stability of motor rotation and extending motor life. This invention aims to reduce the magnetic anisotropy of non-oriented silicon steel, which is more in line with the future development needs of non-oriented silicon steel. In this invention, the electric pulse annealing has higher basic parameters such as current density, frequency, and pulse width. This is to ensure that the pulse annealing temperature can be higher than the complete recrystallization temperature of non-oriented silicon steel, which helps to shorten the annealing time, improve the magnetic properties of the finished sheet, and reduce iron loss. The pulsed current of this invention can be applied at different angles along the rolling direction because the initial texture of cold-rolled non-oriented silicon steel differs in different directions, which affects the texture type and distribution after electrical pulse annealing. This invention uses electrical pulses to promote the transformation of high-resistance textures (such as cold-rolled Goss texture, λ texture, etc.) to low-resistance textures (such as recrystallized γ texture) in the current direction. In actual production, the electrical pulse annealing direction can be adjusted according to the rolling texture type to reduce magnetic anisotropy.

[0047] The principle of this invention is as follows: Electrical pulse annealing can promote the recrystallization process of non-oriented silicon steel. In the rolling direction, it promotes the development of γ-texture, sacrificing some rolling-direction magnetic properties; in the transverse direction, it promotes the development of λ-texture, improving transverse magnetic properties and ultimately reducing the difference in transverse rolling magnetic properties, thus reducing magnetic anisotropy. Furthermore, the interaction between the pulsed current and the self-induced pulsed magnetic field generates an electromagnetic contraction force within the metal. This force repeatedly compresses the metal, improving the uniformity of the annealed structure. Therefore, electrical pulse annealing affects the evolution of transverse rolling texture and promotes the uniform development of the structure, providing a structural guarantee for reducing the magnetic anisotropy of non-oriented silicon steel.

[0048] The following specific examples illustrate the methods used in the examples. Unless otherwise specified, the experimental methods described in the examples are conventional methods. Unless otherwise specified, the reagents and materials described are commercially available.

[0049] In this embodiment of the invention, the composition of the non-oriented silicon steel sample, by weight percentage, is: 0.011 wt% C, 0.050 wt% Cr, 1.985 wt% Si, 0.250 wt% Mn, 0.050 wt% Cu, 0.571 wt% Al, 0.005 wt% V, 0.005 wt% S, 0.04 wt% P, with the balance being Fe.

[0050] In this embodiment of the invention, a magnetic induction intensity and iron loss of the prepared non-oriented silicon steel finished plate were tested using a magnetic measuring instrument (MATS-3000M); the macroscopic texture was observed using an X-ray diffractometer (D8 Advanced X-ray diffractometer). Before the magnetic property testing, the edges were ground with an angle grinder; the XRD test samples were prepared according to standard metallographic methods: the surface of the non-oriented silicon steel perpendicular to the rolling direction was ground with 240-grit, 600-grit, 1000-grit, and 2000-grit sandpaper; and polished with water-soluble diamond polishing paste.

[0051] Example 1:

[0052] This embodiment describes the electro-pulse high-temperature annealing of 0.35mm high-grade non-oriented silicon steel. The specific steps are as follows:

[0053] Step 1: Grind both ends of the 300mm×30mm×0.35mm cold-rolled sample to ensure good contact with the power source;

[0054] Step 2: Place the silicon steel sheet in a N2 protective atmosphere;

[0055] Step 3: Set the pulse current parameters, determining the pulse current frequency to be 1000Hz, the pulse width to be 100µs, and the current density to be 60A / mm². 2 The material undergoes a 150-second pulsed high-temperature annealing process, during which the temperature of the sheet material reaches a maximum of 950℃. Figure 1 The electrical pulse annealing method shown;

[0056] Step 4: The non-oriented silicon steel after high-temperature annealing by electric pulse is air-cooled to room temperature in a protective atmosphere. The resulting finished plate has a transverse {100} texture percentage of 6.64% and a {111} texture percentage of 11.92%; the rolling direction {100} texture percentage is 2% and the {111} texture percentage is 17.21%. Rolling direction B 50 The transverse strength is 1.66T, the transverse strength is 1.62T, and the magnetic anisotropy is 1.81%. Rolling direction P 1.5 / 50 The iron loss is 4.18 W / kg, the transverse iron loss is 4.01 W / kg, and the iron loss anisotropy is 3.9%.

[0057] Comparative Example 2:

[0058] This comparative example demonstrates the conventional heat treatment process of high-temperature annealing for 0.35mm high-grade non-oriented silicon steel. The specific steps are as follows:

[0059] Step 1: Place the 300mm×30mm×0.35mm cold-rolled sample in a tube furnace and introduce N2 protective gas;

[0060] Step 2: Set the temperature of the tube furnace to 950℃ and perform a high-temperature annealing treatment for 150 seconds. Figure 1 The heat treatment annealing method is shown.

[0061] Step 3: The non-oriented silicon steel, after traditional high-temperature annealing, is air-cooled to room temperature in a protective atmosphere. The resulting finished plate has a transverse {100} texture percentage of 2.09% and a {111} texture percentage of 13.96%; a rolling direction {100} texture percentage of 4.2% and a {111} texture percentage of 16.08%. (Rolling direction B) 50 The transverse strength is 1.68T, the transverse strength is 1.61T, and the magnetic anisotropy is 4.17%. Rolling direction P 1.5 / 50 The iron loss is 3.73 W / kg, the transverse iron loss is 4.21 W / kg, and the iron loss anisotropy is 12.97%.

[0062] Figure 2 The experimental results are those obtained in Example 1 and Comparative Example 2. It can be observed that the rolling magnetic induction of the samples decreased after electrical pulse annealing, while the transverse magnetic induction increased. The overall change in magnetic properties of the electrical pulse annealed samples was smaller than that of the conventionally heat-treated annealed samples used in Comparative Example 2, indicating that the electrical pulse annealing used in this invention reduces the magnetic anisotropy of the non-oriented silicon steel.

[0063] Example 2:

[0064] This embodiment describes the electro-pulse high-temperature annealing of 0.35mm high-grade non-oriented silicon steel. The specific steps are as follows:

[0065] Step 1: Grind both ends of the 300mm×30mm×0.35mm cold-rolled sample to ensure good contact with the power source;

[0066] Step 2: Place the silicon steel sheet in a N2 protective atmosphere;

[0067] Step 3: Set the pulse current parameters, determining the pulse current frequency to be 500Hz, the pulse width to be 50µs, and the current density to be 50A / mm². 2 The plate undergoes a 240s current pulse high-temperature annealing treatment, during which the plate temperature rises to a maximum of 860℃.

[0068] Step 4: The non-oriented silicon steel after high-temperature annealing by electric pulse is air-cooled to room temperature in a protective atmosphere. The resulting finished plate has a transverse {100} texture percentage of 13.12% and a {111} texture percentage of 5.41%; and a rolling direction {100} texture percentage of 8.26% and a {111} texture percentage of 10.51%. Rolling direction B 50 The transverse torque is 1.68T, the transverse torque is 1.64T, and the magnetic anisotropy is 2.4%. Rolling direction P 1.5 / 50 The iron loss is 5.20 W / kg, the transverse iron loss is 4.94 W / kg, and the iron loss anisotropy is 5%.

[0069] This embodiment shows that by reducing the current density, frequency, and pulse width, the temperature reached by electrical pulse annealing can be lowered. A lower annealing temperature makes it easier to form recrystallization λ texture, which is beneficial to the improvement of magnetic induction. However, due to insufficient grain growth, iron loss will increase.

[0070] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.< / uvw> < / uvw> < / uvw> < / uvw>

Claims

1. An annealing method for reducing the magnetic anisotropy of non-oriented silicon steel, characterized in that, The method employs high-temperature electrical pulse annealing to reduce the anisotropy of the magnetic properties of non-oriented silicon steel, thereby influencing the ratio of γ-texture to λ-texture in the transverse rolling direction. Including the following steps: S1. After grinding both ends of the non-oriented silicon steel, it is fixed to both ends of the power supply; S2. Place the fixed non-oriented silicon steel in a protective atmosphere; S3. Annealing the non-oriented silicon steel by applying a pulsed current with certain parameters through a power supply, heating the non-oriented silicon steel to a certain temperature and performing high-temperature annealing for a period of time to promote the non-oriented silicon steel's... Texture and The texture is increased by pulse current parameters: pulse frequency 500-2000Hz, pulse width 25-300μs, duty cycle 5-15%, pulse current density 40-100A / mm², and pulse current direction at 0-90° to the rolling direction of the non-oriented silicon steel. The non-oriented silicon steel is heated to 750-1050℃ at a heating rate of 300-500℃ / min and held for 1-30min. The temperature of the non-oriented silicon steel is controlled to complete the corresponding heat treatment at the specified temperature, resulting in more γ texture in the rolling direction and more λ texture in the transverse direction. S4. After high-temperature annealing by electrical pulse, the non-oriented silicon steel is air-cooled to room temperature in a protective atmosphere. The chemical composition of the non-oriented silicon steel, by mass percentage, includes: C: 0.008-0.03%, Si: 1.80-3.20%, Mn: 0.05-0.50%, Al: 0.05-0.80%, P≤0.050%, S≤0.050%, with the remainder being Fe and unavoidable impurities.

2. The annealing method for reducing the magnetic anisotropy of non-oriented silicon steel according to claim 1, characterized in that, The pulse current has a frequency of 500Hz, a pulse width of 50µs, and a current density of 50A / mm. 2 It undergoes a 240s current pulse high-temperature annealing process.

3. The annealing method for reducing the magnetic anisotropy of non-oriented silicon steel according to claim 1, characterized in that, The pulse current has a frequency of 1000Hz, a pulse width of 100µs, and a current density of 60A / mm². 2 .

4. A non-oriented silicon steel, characterized in that, The non-oriented silicon steel is obtained by the annealing method according to any one of claims 1-3, wherein the microstructure of the non-oriented silicon steel is characterized by ferrite as the matrix and a relatively large amount of ferrite in the rolling direction. The texture has more horizontal aspects. Texture.

5. The non-oriented silicon steel according to claim 4, characterized in that, The non-oriented silicon steel B 50 The magnetic flux density is 1.55–1.73 T, and the magnetic anisotropy is 1–10%, of which B 50 The magnetic induction intensity value of non-oriented silicon steel under a magnetic field of 5000 A / m.

6. The non-oriented silicon steel according to claim 4, characterized in that, The P of the non-oriented silicon steel 1.5 / 50 The iron loss is 2.5–4.5 W / kg, and the iron loss anisotropy is 1–10%, of which P 1.5 / 50 Tesla is the electrical energy consumed when a unit mass of non-oriented silicon steel is magnetized to a magnetic induction intensity of 1.5T under a 50Hz alternating magnetic field.

7. The non-oriented silicon steel according to claim 4, characterized in that, The P of the non-oriented silicon steel 1.0 / 400 The iron loss is 25–35 W / kg, and the iron loss anisotropy is 1–10%, of which P 1.0 / 400 This refers to the electrical energy consumed when a unit mass of non-oriented silicon steel is magnetized to a magnetic induction intensity of 1.0T under a 400Hz alternating magnetic field.

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