High-temperature-resistant non-oriented silicon steel and preparation method thereof

Abstract

The invention particularly discloses high-temperature-resistant non-oriented silicon steel and a preparation method thereof, and relates to the technical field of steel smelting, and the high-temperature-resistant non-oriented silicon steel comprises the following chemical components in percentage by mass: 2.85-3.8% of Si, 1.52-2.5% of Al, 2.55-4.0% of Ni, 0.32-1.0% of Cu, 0.15-0.8% of Mn, and the balance of Fe and inevitable impurities. The preparation method comprises the steps of smelting, continuous casting, slab heating, hot rolling, normalizing treatment, coating of a special nano composite additive on the surface of strip steel, warm rolling and cold rolling, recrystallization annealing, aging treatment and coating of an insulating coating. According to the invention, through component design and a nano composite additive coating process, and in cooperation with the precipitation strengthening effect of a NiAl-Cu nanophase, the technical problems that high-silicon aluminum steel is easy to break during rolling, is easy to nodule during high-temperature annealing and is insufficient in high-temperature protective property are effectively solved; and a non-oriented silicon steel product with high strength, low iron loss, high magnetic induction and excellent high-temperature insulation stability is obtained.

Description

Technical Field

[0001] This invention relates to the field of iron and steel smelting technology, specifically to a high-temperature resistant non-oriented silicon steel and its preparation method. Background Technology

[0002] Non-oriented silicon steel, as the core soft magnetic material for motor and generator cores, directly determines the energy conversion efficiency, power density, and operational reliability of electromechanical equipment. Currently, global industry is rapidly developing towards green and efficient directions, placing unprecedented high-performance demands on motors, the core components driving various equipment: miniaturization, lightweighting, high speed, and high power density. This trend forces motors to operate under more demanding conditions, such as higher operating temperatures and stronger electromagnetic loads, posing a severe challenge to the comprehensive performance of its core material, non-oriented silicon steel. An ideal motor core material not only needs excellent soft magnetic properties such as low iron loss and high magnetic induction intensity at high frequencies to improve torque and efficiency, but also must possess sufficiently high mechanical strength to withstand the enormous centrifugal force generated by high-speed rotation, preventing core deformation. Simultaneously, its surface insulating coating must maintain stable and reliable insulation resistance under long-term high-temperature environments to prevent interlayer short circuits and ensure motor lifespan and safety. To meet the requirements of low iron loss magnetic performance, the industry-recognized effective approach is to increase the content of silicon (Si) and aluminum (Al). Si and Al can significantly increase the resistivity of steel, thereby effectively reducing eddy current losses. However, when the Si content exceeds 2.5% and the Al content exceeds 1.5%, the steel matrix exhibits severe processing brittleness due to the formation of ordered phases and increased grain boundary embrittlement. This brittleness easily leads to production accidents such as strip breakage and edge cracking during cold rolling deformation, resulting in low yield and an extremely narrow processing window. This poses a significant obstacle to the industrial continuous production of high-silicon-aluminum content non-oriented silicon steel. Besides the challenges in the rolling process, serious problems also exist in the subsequent annealing stage. To obtain coarse recrystallized grains to optimize magnetic properties, annealing temperatures are typically high (>850℃). At this high temperature, elements on the steel strip surface (especially high-content Si and Al) readily interact slightly with the furnace roll metal, causing "nodule" defects on the steel strip surface. These nodules not only scratch the strip surface, affecting its appearance, but also deteriorate the magnetic domain structure, leading to substandard iron loss and magnetic properties. Furthermore, they damage expensive furnace roll equipment, increasing maintenance costs and time. In terms of insulation performance, traditional non-oriented silicon steel often employs a two-layer system consisting of a chromate pretreatment coating and an organic-inorganic composite coating. Although this system performs well at room temperature, when the motor operates at 180°C or even higher temperatures for extended periods, the traditional organic resin component is prone to thermal degradation and pulverization, while the chromate coating may also undergo property changes due to moisture. Ultimately, this leads to a significant decrease in the interlayer resistance of the insulation coating system, a surge in the risk of insulation failure, and becomes the "Achilles' heel" for the long-term reliable operation of high-end motors.

[0003] In conclusion, the development of a novel high-temperature resistant non-oriented silicon steel and its preparation method has significant practical and strategic value. Summary of the Invention

[0004] The purpose of this invention is to provide a high-temperature resistant non-oriented silicon steel and its preparation method, so as to solve the problems of cold rolling difficulties, easy brittle fracture and low yield caused by poor plasticity and toughness of high silicon aluminum non-oriented silicon steel in the prior art; overcome the problem of easy adhesion to furnace rolls and surface nodule defects during high-temperature annealing; and at the same time improve the shortcomings of its insulating coating, such as easy failure and significant decrease in interlayer resistance under long-term high-temperature service environment.

[0005] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution: This invention relates to a high-temperature resistant non-oriented silicon steel, the chemical composition of which, by mass percentage, is: Si: 2.85~3.8%, Al: 1.52~2.5%, Ni: 2.55~4.0%, Cu: 0.32~1.0%, Mn: 0.15~0.8%, Ti: 0.0018~0.0030%, V: 0.0010~0.0025%, Sn: 0.04~0.07%, C≤0.0025%, N≤0.0025%, S≤0.0015%, with the remainder being Fe and unavoidable impurities.

[0006] Furthermore, a method for preparing high-temperature resistant non-oriented silicon steel includes the following steps: S1. Smelting and continuous casting: The raw materials are smelted in a vacuum induction furnace and then cast into slabs. S2. Slab heating: The slab is heated at high temperature and held at that temperature to ensure that the alloying elements are fully dissolved. S3. Hot rolling: Hot rolling a heated slab to produce a hot-rolled plate; S4. Normalizing treatment: The hot-rolled plate is subjected to normalizing treatment and rapid cooling; S5. Surface treatment: Coat the surface of the normalized strip with a layer of nano-composite additive and dry it; S6. Warm rolling and cold rolling: The coated strip steel is first warm rolled and then cold rolled to the finished thickness. S7. Recrystallization Annealing: Recrystallization annealing is performed on cold-rolled strip in a protective atmosphere; S8. Aging treatment: The annealed strip steel is subjected to low-temperature aging treatment to promote the precipitation of nano-phase. S9. Insulating coating application: Apply an insulating coating to the surface of the steel strip and cure it.

[0007] Further, the nanocomposite additives in step S5 include, by weight, 100 parts deionized water, 15 parts nano silica sol, 8 parts epoxy-modified waterborne acrylic emulsion, 3 parts flake sodium borosilicate, 1.5 parts nano yttrium oxide, 0.8 parts silane coupling agent, 0.1 parts defoamer, and 0.3 parts thickener.

[0008] Furthermore, the preparation method of the nanocomposite additive includes adding a thickener to deionized water and stirring at 300 rpm for 40 minutes; raising the temperature to 50°C, adding a silane coupling agent, and stirring at 200 rpm for 30 minutes for pre-hydrolysis; adding nano-silica sol and nano-yttrium oxide and stirring; adding an antifoaming agent and dispersing at high speed for 60 minutes, controlling the temperature not to exceed 45°C; adding epoxy-modified waterborne acrylic emulsion and flake sodium borosilicate, stirring for 45 minutes, maturing at normal pressure and room temperature for 12 hours, and filtering to obtain the nanocomposite additive.

[0009] Furthermore, in step S1, the vacuum degree of the vacuum induction furnace smelting is controlled at 10 Pa, the smelting temperature is 1500℃, and the refining time is 30 minutes; the thickness of the slab is 220 mm.

[0010] Furthermore, in step S2, the heating temperature of the slab is 1180-1200℃, and the total heating time is 300-360 minutes.

[0011] Furthermore, in step S3, the final rolling temperature of the hot rolling is 780-800℃, and the thickness of the hot-rolled plate is 2.0-2.5mm.

[0012] Furthermore, in step S4, the normalization temperature is 860-900℃, the holding time is 3-5 minutes, and the rapid cooling is water cooling.

[0013] Furthermore, in step S5, the dry film coating amount of the nanocomposite additive is 1.0-1.8 g / m², the drying temperature is 250-280℃, and the drying time is 50-60 seconds.

[0014] Further, in step S6, the rolling temperature of the warm rolling is 200-250℃, the intermediate thickness is 1.0mm, and the finished product thickness is 0.35mm; in step S7, the recrystallization annealing temperature is 840-875℃, the annealing speed is 125-135 m / min, the protective atmosphere is a nitrogen-hydrogen mixed atmosphere, and the dew point of the protective atmosphere is controlled between -30℃ and -15℃; in step S8, the aging treatment temperature is 300-400℃, and the holding time is 15-30 minutes; in step S9, the insulating coating includes a chromate-based primary coating and a heat-resistant epoxy resin secondary coating applied sequentially, with a curing temperature of 160-200℃; the film weight of the primary coating is 2-4 g / m², the film weight of the secondary coating is 4-6 g / m², and the curing temperature is 180℃.

[0015] The technical principle of this invention and its beneficial effects compared with the prior art are described as follows: This invention designs a specific composition system with Si, Al, Ni, and Cu as the core, supplemented by Mn, Ti, V, Sn, and ultra-low impurity elements. It utilizes Ni and Al to form nano-NiAl precipitates during aging treatment, and the synergistic effect of Cu inhibits phase coarsening, thereby achieving high-temperature precipitation strengthening in the matrix. Simultaneously, a novel temporary coating of nanocomposite additives is introduced after normalizing treatment and before cold rolling. This coating plays a lubricating and protective role in subsequent warm and cold rolling processes, effectively improving the rollability of high-silicon aluminum steel, preventing strip breakage, and being decomposed and removed by hydrogen during the annealing preheating stage, avoiding the problem of high-temperature annealing nodule formation. Finally, combined with a specific recrystallization annealing and aging treatment process, and a high-temperature resistant insulating coating system, a comprehensive performance breakthrough is achieved in non-oriented silicon steel, resulting in high strength, low iron loss, high magnetic induction, and excellent high-temperature insulation stability. Attached Figure Description

[0016] Figure 1 This is a microstructure diagram of the high-temperature resistant non-oriented silicon steel of Embodiment 1 of the present invention; Figure 2 This is a microstructure diagram of the high-temperature resistant non-oriented silicon steel of Comparative Example 4 of the present invention. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The concepts involved in this application will first be described with reference to the accompanying drawings. It should be noted that the following descriptions of various concepts are only for the purpose of making the content of this application easier to understand and do not constitute a limitation on the scope of protection of this application; furthermore, the embodiments and features in the embodiments of this application can be combined with each other unless otherwise specified. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] The chromate-based coating was purchased from Henkel as BONDERITE M-CR RC 6100 liquid chromate-treated coating; the heat-resistant epoxy resin coating was purchased from Henkel as LOCTITE ABLESTIK 144A high-temperature resistant epoxy resin.

[0020] This invention provides a high-temperature resistant non-oriented silicon steel, the chemical composition and functions of which are as follows: Si 2.85~3.8%: increases resistivity and reduces iron loss, but excessive Si leads to brittleness. Al 1.52~2.5%: forms NiAl precipitate with Ni, enhancing heat resistance; Ni 2.55~4.0%: forms nano-NiAl phase with Al, providing high-temperature precipitation enhancement; Cu 0.32~1.0%: precipitates synergistically with NiAl, suppressing phase coarsening and increasing interlayer resistivity; Mn 0.15~0.8%: solid solution strengthening, combined with S to avoid hot brittleness; Ti 0.0018~0.0030%, V 0.0010~0.0025%: forms carbonitride pinning grain boundaries; Sn 0.04~0.07%: segregated grain boundaries, optimizing {100} texture; Impurity control: C≤0.0025%, N≤0.0025%, S≤0.0015%, to prevent magnetic aging. Example 1

[0021] This embodiment provides a high-temperature resistant nano-precipitation reinforced non-oriented silicon steel. The chemical composition of the non-oriented silicon steel matrix, by mass percentage, includes: Si 3.80%, Al 2.50%, Ni 4.00%, Mn 0.50%, Cu 1.00%, Ti 0.0018%, V 0.0015%, Sn 0.07%, C 0.0018%, N 0.0020%, S 0.0010%, with the remainder being Fe and unavoidable impurities. The microstructure of this embodiment is shown in the figure below. Figure 1 As shown, by Figure 1It is evident that a uniform grain structure helps reduce the resistance to the movement of magnetic domain walls. No obvious cracks, pores, or abnormally grown grains appeared in the structure, proving that the nanocomposite additives effectively prevented brittle fracture during cold rolling, and the annealing process was smooth without any nodule defects caused by surface problems.

[0022] The preparation method of the high-temperature resistant non-oriented silicon steel includes the following steps: S101 uses industrial pure iron, metallic silicon, metallic aluminum, electrolytic nickel, metallic copper, metallic manganese, tin granules, and ferro-titanium and ferro-vanadium alloys with a purity of not less than 99.99% as raw materials, and smelts them in a vacuum induction furnace. The vacuum degree is controlled below 10Pa, the smelting temperature is 1550℃, and the refining time is 30 minutes to ensure that the alloy elements are fully homogenized. S102. The molten steel is poured into a continuous casting billet with a thickness of 220mm and the billet pulling speed is 1.2m / min; S103. The billet is fed into a walking beam furnace for heating at a temperature of 1200℃ for a total heating time of 360 minutes to ensure that the elements are fully dissolved. S104. After the heated slab is descaled by high-pressure water, it is subjected to hot continuous rolling. Three roughing passes and seven finishing passes are used, with the final rolling temperature controlled at 800℃, to roll it into a hot-rolled plate with a thickness of 2.0mm, and then coil it. S105. The obtained hot-rolled plate was normalized at 900℃ for 5 minutes and then water-cooled to room temperature to obtain a uniform microstructure with a grain size of about 90μm. S106, after normalizing, the surface of the strip steel is coated with nano-composite additives by roller coating, the dry film coating amount is controlled at 1.8g / m², and it is treated in a drying oven at 280℃ for 60 seconds. S107. The coated strip steel is warm rolled at 250°C to an intermediate thickness of 1.0 mm; it is then cold rolled again at room temperature to a final finished thickness of 0.35 mm. S108. The cold-rolled strip is subjected to recrystallization annealing. The annealing temperature is set to 875℃, the annealing speed is set to 125m / min, and the annealing atmosphere is a nitrogen-hydrogen mixed atmosphere. The dew point is controlled at -30℃; in particular, a low-temperature preheating section (300-600℃) is set in the annealing furnace, during which the H2 in the protective atmosphere can decompose and remove the organic components in the temporary coating.

[0023] S109. The annealed strip is aged at 400℃ for 30 minutes to promote the full precipitation of NiAl-Cu nanophase. S1010. Apply an insulating coating to the surface of the strip steel (chromate-based coating as the primary coating, film weight 3g / m²; heat-resistant epoxy resin coating as the secondary coating, film weight 5g / m²), and dry and cure at 180℃ for 2 minutes to obtain the finished high-temperature resistant non-oriented silicon steel.

[0024] The performance tests of the embodiments and comparative examples of this invention were all conducted in accordance with Chinese national standards (GB / T). Specifically, the room temperature tensile test was performed according to GB / T 228.1-2021, determining the yield strength (Rp0.2); magnetic properties ( The Epstein square circle method was used to determine the thermal insulation properties according to GB / T 3655-2008; the inter-sheet insulation resistance was evaluated by measuring the inter-sheet insulation resistance according to GB / T 2522-2017 after heat treatment at 180℃ for 48 hours; the pencil hardness of the coating was determined according to GB / T 6739-2006. All tests were conducted at room temperature (23±5℃) to ensure the accuracy and comparability of the results.

[0025] The non-oriented silicon steel product prepared in this embodiment, after testing, showed a yield strength Rp0.2 of 950 MPa and an iron loss of [missing information]. 32W / kg, magnetic induction It reaches 1.67T. After being placed at 180℃ for 48 hours, its insulation resistance is still greater than 20000Ω·mm² / piece, demonstrating excellent high-temperature mechanical properties, magnetic properties and thermal stability.

[0026] To address the challenges of brittle fracture during high-silicon aluminum steel rolling, nodule formation during high-temperature annealing, and insufficient protective properties of existing insulating coatings in high-temperature and high-humidity environments, this invention designs a nanocomposite additive, primarily used for surface treatment of hot-rolled plates after normalizing and before cold rolling. The nanocomposite additive comprises, by weight, 100 parts deionized water and 15 parts nano-silica sol (…). ), 8 parts GK-HY2509 epoxy-modified waterborne acrylic emulsion (solid content 40%), 3 parts flake sodium borosilicate (particle size ≤ 5μm), 1.5 parts nano yttrium oxide ( 0.8 parts silane coupling agent (KH-560), 0.1 parts polyether modified polysiloxane defoamer and 0.3 parts hydroxyethyl cellulose (thickener).

[0027] The preparation method of the nanocomposite additive includes: adding 0.3 parts of hydroxyethyl cellulose to deionized water at a stirring speed of 300 rpm for 40 minutes, raising the temperature of the reaction vessel to 50°C, adding silane coupling agent KH-560, stirring at 200 rpm for 30 minutes for pre-hydrolysis, adding nano silica sol and nano yttrium oxide powder and stirring, adding 0.1 parts of defoamer, dispersing at high speed for 60 minutes, controlling the temperature not to exceed 45°C during this period, adding GK-HY2509 epoxy-modified waterborne acrylic emulsion and flake sodium borosilicate, stirring for 45 minutes, maturing at normal pressure and room temperature for 12 hours, and filtering with a 200-mesh sieve to obtain the nanocomposite additive. Example 2

[0028] This embodiment provides a high-temperature resistant nano-precipitation reinforced non-oriented silicon steel. The chemical composition of the non-oriented silicon steel matrix, by mass percentage, includes: Si 2.85%, Al 1.52%, Ni 2.55%, Mn 0.15%, Cu 0.32%, Ti 0.0029%, V 0.0024%, Sn 0.04%, C 0.0024%, N 0.0024%, S 0.0014%, with the remainder being Fe and unavoidable impurities.

[0029] The preparation method of the high-temperature resistant non-oriented silicon steel includes the following steps: Raw materials and smelting steps are the same as in Example 1, smelting in a vacuum induction furnace at a smelting temperature of 1550℃; continuous casting steps are the same as in Example 1, casting into a 220mm thick continuous casting billet; billet heating temperature is 1180℃, total heating time is 300 minutes; hot rolling steps are the same as in Example 1, but the final rolling temperature is controlled at 780℃; normalizing treatment temperature is 860℃, holding time is 3 minutes, followed by water cooling; surface coating with nano-composite additives, dry film coating amount is controlled at 1.0 g / m², treated in a drying oven at 250℃ for 50 seconds; warm rolling and cold rolling steps are the same as in Example 1 S107; annealing temperature is set at 840℃, annealing speed is set at 135 m / min. Annealing atmosphere dew point is controlled at -15℃; aging treatment temperature is 300℃, holding time is 15 minutes; coating with insulating coating and curing steps are the same as in Example 1.

[0030] The non-oriented silicon steel product prepared in Example 2, after testing, has a yield strength Rp0.2 of 710 MPa and an iron loss of... 48 W / kg, magnetic induction The resistance is 1.58T. After being placed at 180℃ for 48 hours, its insulation resistance drops to 8500 Ω·mm² / piece. Example 3

[0031] In this embodiment, by adjusting the composition and process parameters, the chemical composition of the non-oriented silicon steel matrix includes, by mass percentage: Si 3.30%, Al 2.00%, Ni 3.20%, Mn 0.50%, Cu 0.65%, Ti 0.0022%, V 0.0018%, Sn 0.055%, C 0.0020%, N 0.0022%, S 0.0012%, with the remainder being Fe and unavoidable impurities.

[0032] The preparation method of the high-temperature resistant non-oriented silicon steel includes the following steps: the raw materials and smelting steps are the same as in Example 1; the continuous casting steps are the same as in Example 1; the billet heating temperature is 1190℃, and the total heating time is 330 minutes; the hot continuous rolling steps are the same as in Example 1, and the final rolling temperature is controlled at 790℃; the normalizing treatment temperature is 880℃, the holding time is 4 minutes, and water cooling is performed; the surface is coated with a nano-composite additive, the dry film coating amount is controlled at 1.5 g / m², and the surface is treated in a drying oven at 270℃ for 55 seconds; the warm rolling and cold rolling steps are the same as in Example 1; the annealing temperature is set at 860℃, and the annealing speed is set at 130 m / min. The annealing atmosphere dew point is controlled at -25℃; the aging treatment temperature is 350℃, and the holding time is 25 minutes; the coating of the insulating coating and the curing steps are the same as in Example 1.

[0033] The non-oriented silicon steel product prepared in Example 3, after testing, has a yield strength Rp0.2 of 820 MPa and an iron loss of... 39 W / kg, magnetic induction The resistance is 1.62T. After being placed at 180℃ for 48 hours, its insulation resistance is 15000 Ω·mm² / piece.

[0034] Comparative Example 1 The difference from Example 1 is that the silicon content was adjusted to 2.7%, while the other components and preparation process remained the same as in Example 1. The finished product, after testing, had a yield strength Rp0.2 of 810 MPa and an iron loss of... 45 W / kg, magnetic induction The resistance was 1.60T. After being placed at 180℃ for 48 hours, the insulation resistance was 12000 Ω·mm² / piece. The data shows that the decrease in silicon content leads to a decrease in resistivity, a significant increase in high-frequency iron loss, and a significant deterioration in strength and heat resistance, proving that the high silicon content in Example 1 is crucial to the overall performance.

[0035] Comparative Example 2 The difference from Example 1 is that nickel is not added; its content is 0%, and the missing element is made up by iron. Other components and preparation processes are the same as in Example 1. The resulting product, upon testing, showed a significant decrease in yield strength Rp0.2 to 650 MPa, but iron loss... The strength deteriorated to 52 W / kg. This indicates that the lack of nickel prevents the formation of the crucial NiAl nanoprecipitates, resulting in insufficient high-temperature strength. Simultaneously, the magnetic properties were severely degraded due to the imbalance in the composition system, proving that nickel is an indispensable component for simultaneously achieving high strength and high magnetic induction.

[0036] Comparative Example 3 The difference from Example 1 is that the aging treatment in step S109 is omitted; the cold-rolled strip is directly coated after recrystallization annealing. Everything else is the same as in Example 1. The resulting product showed a yield strength Rp0.2 reduced to 720 MPa, while its magnetic properties (iron loss and magnetic induction) were similar to those of Example 1. This result directly proves that the aging treatment is a key step in stimulating NiAl-Cu nanophase precipitation and achieving precipitation strengthening. Without this step, the product's strength advantage is lost, highlighting the indispensability of the complete process design of this invention.

[0037] Comparative Example 4 The difference from Example 1 is the absence of the nanocomposite additive coating and drying in step S106, where equal parts by weight are used. After normalizing, it is directly subjected to warm rolling and cold rolling. Everything else is the same as in Example 1. The prepared product, after testing, exhibits iron loss... 33W / kg, magnetic induction The yield was 1.65T, but multiple strip breaks occurred during cold rolling, resulting in increased surface scratches on the finished product. After annealing, localized furnace roll nodules appeared on the strip surface. The microstructure of this comparative example is shown in the figure below. Figure 2 As shown, by Figure 2 It can be seen that, Figure 2 The microstructure of the high-silicon aluminum steel exhibits obvious inhomogeneity. In contrast, the lack of lubrication and protection from nanocomposite additives in Comparative Example 4 exposes the inherent brittleness of the high-silicon aluminum steel during cold rolling deformation, resulting in multiple strip breaks and surface scratches. These macroscopic defects manifest as microcracks and uneven deformation in the microstructure. The lack of protective decomposition of additives in the annealing and preheating section means that the strip surface is in direct contact with the high-temperature furnace atmosphere and is prone to react with the furnace rolls, producing local furnace roll nodule marks.

[0038] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. A high-temperature resistant non-oriented silicon steel, characterized in that, Its chemical composition by mass percentage is as follows: Si: 2.85~3.8%, Al: 1.52~2.5%, Ni: 2.55~4.0%, Cu: 0.32~1.0%, Mn: 0.15~0.8%, Ti: 0.0018~0.0030%, V: 0.0010~0.0025%, Sn: 0.04~0.07%, C≤0.0025%, N≤0.0025%, S≤0.0015%, with the remainder being Fe and unavoidable impurities.

2. The method for preparing high-temperature resistant non-oriented silicon steel according to claim 1, characterized in that, Includes the following steps: S1. Smelting and continuous casting: The raw materials are smelted in a vacuum induction furnace and then cast into slabs. S2. Slab heating: The slab is heated at high temperature and held at that temperature to ensure that the alloying elements are fully dissolved. S3. Hot rolling: Hot rolling a heated slab to produce a hot-rolled plate; S4. Normalizing treatment: The hot-rolled plate is subjected to normalizing treatment and rapid cooling; S5. Surface treatment: Coat the surface of the normalized strip with a layer of nano-composite additive and dry it; S6. Warm rolling and cold rolling: The coated strip steel is first warm rolled and then cold rolled to the finished thickness. S7. Recrystallization Annealing: Recrystallization annealing is performed on cold-rolled strip in a protective atmosphere; S8. Aging treatment: The annealed strip steel is subjected to low-temperature aging treatment to promote the precipitation of nano-phase. S9. Insulating coating application: Apply an insulating coating to the surface of the steel strip and cure it.

3. The preparation method according to claim 2, characterized in that, The nanocomposite additives in step S5 include, by weight, 100 parts deionized water, 15 parts nano silica sol, 8 parts epoxy-modified waterborne acrylic emulsion, 3 parts flake sodium borosilicate, 1.5 parts nano yttrium oxide, 0.8 parts silane coupling agent, 0.1 parts defoamer, and 0.3 parts thickener.

4. The preparation method according to claim 3, characterized in that, The preparation method of the nanocomposite additive includes adding a thickener to deionized water and stirring at 300 rpm for 40 minutes; raising the temperature to 50°C, adding a silane coupling agent, and stirring at 200 rpm for 30 minutes for pre-hydrolysis; adding nano-silica sol and nano-yttrium oxide and stirring; adding an antifoaming agent and dispersing at high speed for 60 minutes, controlling the temperature not to exceed 45°C; adding epoxy-modified waterborne acrylic emulsion and flake sodium borosilicate, stirring for 45 minutes, maturing at normal pressure and room temperature for 12 hours, and filtering to obtain the nanocomposite additive.

5. The preparation method according to claim 2, characterized in that, In step S1, the vacuum degree of the vacuum induction furnace is controlled at 10 Pa, the smelting temperature is 1500℃, and the refining time is 30 minutes; the thickness of the slab is 220 mm.

6. The preparation method according to claim 2, characterized in that, In step S2, the heating temperature of the slab is 1180-1200℃, and the total heating time is 300-360 minutes.

7. The preparation method according to claim 2, characterized in that, In step S3, the final rolling temperature of the hot rolling is 780-800℃, and the thickness of the hot-rolled plate is 2.0-2.5mm.

8. The preparation method according to claim 2, characterized in that, In step S4, the normalization temperature is 860-900℃, the holding time is 3-5 minutes, and the rapid cooling is water cooling.

9. The preparation method according to claim 2, characterized in that, In step S5, the dry film coating amount of the nanocomposite additive is 1.0-1.8 g / m², the drying temperature is 250-280℃, and the drying time is 50-60 seconds.

10. The preparation method according to claim 2, characterized in that, In step S6, the rolling temperature of the warm rolling is 200-250℃, the intermediate thickness is 1.0mm, and the finished thickness is 0.35mm. In step S7, the recrystallization annealing temperature is 840-875℃, the annealing speed is 125-135 m / min, the protective atmosphere is a nitrogen-hydrogen mixed atmosphere, and the dew point of the protective atmosphere is controlled between -30℃ and -15℃. In step S8, the aging treatment temperature is 300-400℃, and the holding time is 15-30 minutes. In step S9, the insulating coating includes a chromate-based primary coating and a heat-resistant epoxy resin secondary coating applied sequentially, with a curing temperature of 160-200℃. The film weight of the primary coating is 2-4 g / m², the film weight of the secondary coating is 4-6 g / m², and the curing temperature is 180℃.

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