Ultra-thin specification non-oriented silicon steel plate with ultrahigh magnetic induction and preparation method thereof

Abstract

The invention discloses an ultra-high magnetic induction ultra-thin specification non-oriented silicon steel plate and a preparation method thereof.The preparation method of the ultra-high magnetic induction ultra-thin specification non-oriented silicon steel plate comprises the steps of molten steel smelting, continuous casting, hot rolling, first-time cold rolling annealing, second-time cold rolling annealing, third-time cold rolling annealing and coating. The ultra-thin specification non-oriented silicon steel plate with ultrahigh magnetic induction comprises the following chemical components in percentage by mass: 0.5%-1.5% of Si, 0.10%-0.25% of Al, 0.15%-0.45% of Mn, 0.02%-0.11% of P, less than or equal to 0.002% of S, less than or equal to 0.002% of N, 0.001%-0.003% of C and the balance of iron and inevitable impurities. On the premise of low Si and Al alloy components, strong Goss and {001} lt are obtained in a finished plate through a three-time cold rolling method; 0vwgt, 0vwgt; the non-oriented silicon steel ultra-thin strip is excellent in texture and steel plate magnetic performance, ultrahigh in magnetic induction intensity and low in iron loss, and the problems that an existing non-oriented silicon steel ultra-thin strip is large in preparation process difficulty and low in magnetic performance are solved. And the magnetic performance and the rollability of the non-oriented silicon steel ultra-thin strip are effectively considered.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, and particularly relates to an ultra-thin non-oriented silicon steel plate with ultra-high magnetic induction and its preparation method. Background Technology

[0002] Non-oriented silicon steel is a core soft magnetic material for manufacturing the cores of motors, generators, and compressors, and its magnetic properties directly affect the energy efficiency of the equipment. With the rapid development of new energy vehicles, high-efficiency industrial motors, and renewable energy equipment, the market demand for the magnetic properties of non-oriented silicon steel is increasing to reduce equipment losses, improve power density, and meet energy efficiency standards. According to classical eddy current loss theory, eddy current loss is proportional to both the operating frequency and the square of the steel plate thickness. When the motor's operating frequency is in the high-frequency range, the eddy current loss of non-oriented silicon steel will increase significantly. Reducing the thickness of the non-oriented silicon steel can effectively reduce high-frequency iron losses. However, reducing the thickness means increasing the cold rolling reduction rate. The severe plastic deformation caused by large reductions in cold rolling leads to conditions unfavorable to magnetization. <uvw>The recrystallization texture is significantly enhanced, leading to a deterioration in magnetic properties. Therefore, the development of high-performance, ultra-thin non-oriented silicon steel sheets is of great significance for promoting technological progress in the non-oriented silicon steel industry and the high-quality development of the power and electronics industries.

[0003] Patent CN105803311A discloses a method for manufacturing high-strength non-oriented silicon steel for drive motors of new energy vehicles. This method uses thin-strip continuous casting technology to prepare the high-strength non-oriented silicon steel and adds trace elements such as Ni, Cr, and Sn to the composition. Although this method has a shorter process flow, it places higher demands on equipment, smelting, and each process, and the composition system is more complex, resulting in higher production costs.

[0004] Japanese patent JFE (JP2005-2272913) discloses a conventional process for producing high-strength non-oriented silicon steel. The main principle is to utilize the precipitation strengthening mechanism of elemental Cu. Cu (0.6~1.1%) is added during steelmaking, and the precipitation of Cu in the non-oriented silicon steel production process is well controlled, which improves strength while ensuring magnetic properties. However, the addition of Cu is prone to "copper brittleness", which may lead to unstable performance. There is still a long way to go before it can be industrialized.

[0005] Patent CN115522127B discloses an ultrathin non-oriented silicon steel and its manufacturing method, which uses normalizing and secondary cold rolling to obtain the ultrathin non-oriented silicon steel. The ultrathin non-oriented silicon steel prepared by this production method does not require a high Si content while possessing good magnetic properties, but it needs to maintain a relatively thin final hot-rolled thickness, placing high demands on the hot rolling equipment. At the same time, the production process retains the normalizing process after hot rolling, increasing the production flow of the ultrathin non-oriented silicon steel and reducing production efficiency. Summary of the Invention

[0006] To address some or all of the technical problems existing in the prior art, the present invention provides an ultra-thin non-oriented silicon steel sheet with high magnetic induction and a method for preparing the same.

[0007] The method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction of the present invention includes: steel smelting - continuous casting - hot rolling - first cold rolling annealing - second cold rolling annealing - third cold rolling annealing - coating. The chemical composition of the ultra-thin non-oriented silicon steel sheets with high magnetic induction is controlled by mass percentage as follows: Si: 0.5%~1.5%, Al: 0.10%~0.25%, Mn: 0.15%~0.45%, P: 0.02%~0.11%, S≤0.002%, N≤0.002%, C: 0.001%~0.003%, with the remainder being iron and unavoidable impurities. Steel smelting: The process of melting raw materials to obtain molten steel with the target element content; Continuous casting: casting molten steel into continuous casting billets of 200mm~250mm; Hot rolling: The billet is heated to 1100℃~1200℃ in a heating furnace, held for 1h~2h and then hot rolled to obtain a hot-rolled plate with a thickness of 2.0mm~2.8mm. First cold rolling annealing: The hot-rolled plate is pickled to remove the surface iron oxide scale, and then cold-rolled to a thickness of 0.5mm~0.6mm. It is then held at 850℃~900℃ for 2min~5min under a protective atmosphere to obtain the first annealed plate. Second cold rolling annealing: The first annealed plate is pickled to remove the surface iron oxide scale, and the cold rolling reduction rate is controlled at 5%~15%. The plate is then held at 850℃~900℃ for 2min~5min under a protective atmosphere to obtain the second annealed plate. Third cold rolling annealing: The hot-rolled plate is pickled to remove the surface iron oxide scale, and then cold-rolled to a thickness of 0.1mm~0.2mm. It is then held at 900℃~1000℃ for 2min~5min under a protective atmosphere to obtain the third annealed plate. Coating: Apply a coating to the third annealed plate.

[0008] Furthermore, in the above-mentioned method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction, the final rolling temperature is controlled at 850℃~900℃ during the hot rolling step.

[0009] Furthermore, in the above-mentioned method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction, in the first cold rolling annealing step, the protective atmosphere is a mixture of N2 and H2, wherein the volume percentage of H2 is 10%~50%.

[0010] Furthermore, in the above-mentioned method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction, in the second cold rolling annealing step, the protective atmosphere is a mixture of N2 and H2, wherein the volume percentage of H2 is 10%~50%.

[0011] Furthermore, in the above-mentioned method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction, the average grain size is controlled to be 0.6 mm to 1.0 mm in the second cold rolling annealing step.

[0012] Furthermore, in the above-mentioned method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction, in the third cold rolling annealing step, the protective atmosphere is a mixture of N2 and H2, wherein the volume percentage of H2 is 10%~50%.

[0013] In a second aspect of the invention, an ultra-thin non-oriented silicon steel sheet with high magnetic induction is provided, which is produced using a method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction.

[0014] The ultra-thin, non-oriented silicon steel sheet with high magnetic induction and its preparation method of the present invention have the following advantages and beneficial effects: Under the premise of low Si and Al alloy composition, the present invention obtains strong Goss and {001}<0vw> textures in the finished sheet through a three-stage cold rolling process. The steel sheet has excellent magnetic properties, with ultra-high magnetic induction and low iron loss, solving the problems of difficult preparation process and low magnetic properties of existing ultra-thin non-oriented silicon steel strips. It effectively balances the magnetic properties and rollability of ultra-thin non-oriented silicon steel strips. It requires no high-temperature normalizing furnace or the addition of precious metal elements such as Sb or Sn, and has low requirements for production equipment, enabling stable batch production in industrial production. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for further understanding of the embodiments of the present invention and constitute a part of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the microstructure of the secondary annealed plate in the preparation method of ultra-thin non-oriented silicon steel plate with high magnetic induction of the present invention. Figure 2 This is a grain orientation distribution diagram of the finished plate of the present invention; Figure 3 This is a macroscopic texture diagram of the finished product board of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0017] The method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction of the present invention includes: steel smelting - continuous casting - hot rolling - first cold rolling annealing - second cold rolling annealing - third cold rolling annealing - coating. The chemical composition of the ultra-thin non-oriented silicon steel sheets with high magnetic induction is controlled by mass percentage as follows: Si: 0.5%~1.5%, Al: 0.10%~0.25%, Mn: 0.15%~0.45%, P: 0.02%~0.11%, S≤0.002%, N≤0.002%, C: 0.001%~0.003%, with the remainder being iron and unavoidable impurities. C: An unavoidable impurity element in steel. Whether C exists in the form of solid solution or cementite, it will impair the magnetic properties of the steel plate. Therefore, the C content is controlled at 0.001%~0.003%.

[0018] Si: Increased Si content increases the strength of steel plates, reduces magnetic induction, and increases the brittleness of steel plates, which is not conducive to rolling and surface quality control of hot-rolled coils. Therefore, the Si content is kept low and controlled between 0.5% and 1.5%.

[0019] Mn: Mn is beneficial for increasing the resistivity of silicon steel and reducing iron loss. However, Mn can increase strength through solid solution strengthening, and excessively high strength is not conducive to subsequent rolling processes. Therefore, the Mn content should be controlled between 0.15% and 0.45%.

[0020] Al: Increasing the Al content increases the strength and magnetic induction of the steel plate, but excessive Al content can easily cause the molten steel to become sticky. Therefore, the Al content is controlled between 0.10% and 0.25%.

[0021] P: P is a solid solution strengthening element that can cause segregation, refine grains, increase strength, and improve texture. However, Fe3P segregation can make steel plates embrittled and reduce toughness. Therefore, the P content should be controlled between 0.02% and 0.11%.

[0022] N / S: N can form AlN inclusions with Al in steel, and S can form ductile MnS inclusions with Mn in steel, which can reduce hot brittleness, but will lead to the formation of banded structure in the strip, reduce the toughness and formability of the steel plate, and N / S has a great influence on magnetic properties. The N / S content should be controlled to ≤0.002%.

[0023] To reduce production costs, no precious metal elements such as Sn or Sb are added in this invention.

[0024] The magnetic induction intensity B50 of ultra-thin non-oriented silicon steel sheets is 1.80~1.86T, the iron loss P1.5 / 50 ≤ 2.8W / Kg, and the iron loss P1.0 / 400 ≤ 21.0W / Kg. Steel smelting: The process of melting raw materials to obtain molten steel with the target element content; Continuous casting: casting molten steel into continuous casting billets of 200mm~250mm; Hot rolling: The billet is heated to 1100℃~1200℃ in a heating furnace, held for 1h~2h and then hot rolled to obtain a hot rolled plate with a thickness of 2.0mm~2.8mm. When the hot rolled thickness is controlled at 2.0mm~2.8mm, the requirements for hot rolling equipment are lower, thereby reducing production costs. First cold rolling annealing: The hot-rolled plate is pickled to remove the surface iron oxide scale and cold rolled to a thickness of 0.5mm~0.6mm. It is then held at 850℃~900℃ for 2min~5min under a protective atmosphere to obtain the first annealed plate. After cold rolling with a large reduction rate and matching a higher annealing temperature, a significant thinning is achieved to obtain a fully recrystallized structure. Second cold rolling annealing: The first annealed plate is pickled to remove the surface iron oxide scale, and the cold rolling reduction rate is controlled at 5%~15%. The plate is then held at 850℃~900℃ for 2min~5min under a protective atmosphere to obtain the second annealed plate. Energy is stored through a small deformation. Because the energy stored during annealing is low, recrystallization is not likely to occur, but it is beneficial to obtain abnormally grown coarse grains through deformation-induced grain boundary migration. Third cold rolling annealing: The hot-rolled plate is pickled to remove the surface iron oxide scale, and then cold-rolled to a thickness of 0.1mm~0.2mm. It is then held at 900℃~1000℃ for 2min~5min under a protective atmosphere to obtain the third annealed plate. A moderate reduction rate in the third cold rolling process easily causes intragranular strain localization in the coarse grains of the second annealed plate, forming high-density shear bands, which promotes the {110} process. <001> The nucleation and growth of the recrystallization texture of {001}<0vw> are enhanced; on the other hand, such coarse grains accumulate less deformation storage energy during the three cold rolling processes, which suppresses the unfavorable {111} <uvw>The development of texture. Therefore, after final annealing, {110} can be significantly improved. <001> And {001}<0vw> are beneficial to texture and reduce {111} <uvw>Unfavorable texture, thus greatly enhancing magnetic induction; Coating: Apply a coating to the third annealed plate.

[0025] Furthermore, in the above-mentioned method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction, the final rolling temperature is controlled at 850℃~900℃ during the hot rolling step.

[0026] Furthermore, in the above-mentioned method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction, in the first cold rolling annealing step, the protective atmosphere is a mixture of N2 and H2, wherein the volume percentage of H2 is 10%~50%.

[0027] Furthermore, in the above-mentioned method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction, in the second cold rolling annealing step, the protective atmosphere is a mixture of N2 and H2, wherein the volume percentage of H2 is 10%~50%.

[0028] Furthermore, in the above-mentioned method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction, the average grain size is controlled to be 0.6 mm to 1.0 mm in the second cold rolling annealing step.

[0029] Furthermore, in the above-mentioned method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction, in the third cold rolling annealing step, the protective atmosphere is a mixture of N2 and H2, wherein the volume percentage of H2 is 10%~50%.

[0030] In a second aspect of the invention, an ultra-thin non-oriented silicon steel sheet with high magnetic induction is provided, which is produced using a method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction.

[0031] Example 1: Steel smelting: The raw materials are smelted to obtain molten steel with the following chemical composition controlled by mass percentage: Si: 1.3%, Al: 0.20%, Mn: 0.3%, P: 0.02%, S: 0.0015%, N: 0.0014%, C: 0.002%, with the remainder being iron and unavoidable impurities; Continuous casting: casting molten steel into a continuous casting billet with a thickness of 220mm; Hot rolling: The continuously cast billet is heated to 1150℃ and held for 1 hour before hot rolling to obtain a hot-rolled plate with a thickness of 2.5mm. First cold rolling annealing: The hot-rolled plate is pickled to remove the surface iron oxide scale, cold rolled to 0.55 mm, and held at 880℃ for 4 min in an atmosphere with a volume ratio of 10% H2 to obtain a first annealed plate; Second cold rolling annealing: After pickling the first annealed plate, it is cold rolled to a thickness of 0.50 mm, and held at 880°C for 4 min in an atmosphere of 10% H2 by volume to obtain a second annealed plate with an average grain size of 0.75 mm. Third cold rolling annealing: After pickling the second annealed plate, it is cold rolled to a final thickness of 0.1 mm; and held at 950°C for 4 min in an atmosphere with a volume ratio of 10% H2. Coating: The third annealed plate is coated with a coating to obtain a non-oriented silicon steel plate.

[0032] The magnetic properties of the above-mentioned non-oriented silicon steel sheet are: magnetic induction intensity B50=1.86T, iron loss P1.5 / 50≤2.4W / Kg, and iron loss P1.0 / 400≤11.0W / Kg.

[0033] Example 2: Steel smelting: The raw materials are smelted to obtain molten steel with the following chemical composition controlled by mass percentage: Si: 1.1%, Al: 0.15%, Mn: 0.35%, P: 0.02%, S: 0.0015%, N: 0.0015%, C: 0.002%, with the remainder being iron and unavoidable impurities; Continuous casting: casting molten steel into a continuous casting billet with a thickness of 230mm; Hot rolling: The continuously cast billet is heated to 1100℃ and held for 1 hour before hot rolling to obtain a hot-rolled plate with a thickness of 2.4 mm. First cold rolling annealing: The hot-rolled plate is pickled to remove the surface iron oxide scale, cold rolled to 0.54 mm, and held at 850℃ for 5 min in an atmosphere with a volume ratio of 25% H2 to obtain a first annealed plate; Second cold rolling annealing: After pickling the first annealed plate, it is cold rolled to a thickness of 0.50 mm, and held at 850°C for 5 min in an atmosphere of 25% H2 by volume to obtain a second annealed plate with an average grain size of 0.68 mm. Third cold rolling annealing: After pickling the second annealed plate, it is cold rolled to a final thickness of 0.1 mm; and held at 970°C for 4 min in an atmosphere with a volume ratio of 25% H2. Coating: The third annealed plate is coated with a coating to obtain a non-oriented silicon steel plate.

[0034] The magnetic properties of the above-mentioned non-oriented silicon steel sheet are: magnetic induction intensity B50=1.85T, iron loss P1.5 / 50≤2.5W / Kg, and iron loss P1.0 / 400≤12.2W / Kg.

[0035] Example 3: Steel smelting: The raw materials are smelted to obtain molten steel with the following chemical composition controlled by mass percentage: Si: 1.05%, Al: 0.16%, Mn: 0.35%, P: 0.015%, S: 0.0015%, N: 0.0015%, C: 0.002%, with the remainder being iron and unavoidable impurities; Continuous casting: casting molten steel into a continuous casting billet with a thickness of 210mm; Hot rolling: The continuously cast billet is heated to 1120℃ and held for 1.5 hours before hot rolling to obtain a hot-rolled plate with a thickness of 2.3 mm. First cold rolling annealing: The hot-rolled plate is pickled to remove the surface iron oxide scale, cold rolled to 0.56 mm, and held at 900℃ for 4 min in an atmosphere with a volume ratio of 20% H2 to obtain a first annealed plate; Second cold rolling annealing: After pickling the first annealed plate, it is cold rolled to a thickness of 0.2 mm, and held at 950°C for 4 min in an atmosphere with a volume ratio of 20% H2 to obtain a second annealed plate with an average grain size of 0.78 mm. Third cold rolling annealing: After pickling the second annealed plate, it is cold rolled to a final thickness of 0.2 mm; and held at 950°C for 4 min in an atmosphere with a volume ratio of 20% H2. Coating: The third annealed plate is coated with a coating to obtain a non-oriented silicon steel plate.

[0036] The magnetic properties of the above-mentioned non-oriented silicon steel sheet are: magnetic induction intensity B50=1.83T, iron loss P1.5 / 50≤2.6W / Kg, and iron loss P1.0 / 400≤19.6W / Kg.

[0037] Example 4: Steel smelting: The raw materials are smelted to obtain molten steel with the following chemical composition controlled by mass percentage: Si: 0.6%, Al: 0.14%, Mn: 0.30%, P: 0.016%, S: 0.0018%, N: 0.0018%, C: 0.0016%, with the remainder being iron and unavoidable impurities; Continuous casting: casting molten steel into a continuous casting billet with a thickness of 230mm; Hot rolling: The continuously cast billet is heated to 1120℃ and held for 1.5 hours before hot rolling to obtain a hot-rolled plate with a thickness of 2.6 mm. First cold rolling annealing: The hot-rolled plate is pickled to remove the surface iron oxide scale, cold rolled to 0.55 mm, and held at 860℃ for 4 min in an atmosphere with a volume ratio of 15% H2 to obtain a first annealed plate; Second cold rolling annealing: After pickling the first annealed plate, it is cold rolled to a thickness of 0.50 mm, and held at 860°C for 4 min in an atmosphere of 15% H2 by volume to obtain a second annealed plate with an average grain size of 0.70 mm. Third cold rolling annealing: After pickling the second annealed plate, it is cold rolled to a final thickness of 0.2 mm; and held at 970°C for 4 min in an atmosphere with a volume ratio of 15% H2. Coating: The third annealed plate is coated with a coating to obtain a non-oriented silicon steel plate.

[0038] The magnetic properties of the above-mentioned non-oriented silicon steel sheet are: magnetic induction intensity B50=1.82T, iron loss P1.5 / 50≤2.8W / Kg, and iron loss P1.0 / 400≤20.5W / Kg.

[0039] Comparative Example 1: Steel smelting: The raw materials are smelted to obtain molten steel with the following chemical composition controlled by mass percentage: Si: 1.1%, Al: 0.15%, Mn: 0.35%, P: 0.02%, S: 0.0015%, N: 0.0014%, C: 0.002%, with the remainder being iron and unavoidable impurities; Continuous casting: casting molten steel into a continuous casting billet with a thickness of 220mm; Hot rolling: The continuously cast billet is heated to 1110℃ and held for 1 hour before hot rolling to obtain a hot-rolled plate with a thickness of 2.5mm. Cold rolling: The hot-rolled plate is pickled to remove the surface iron oxide scale, and then cold-rolled to 0.1mm; Annealing: The cold-rolled sheet is annealed under a protective atmosphere; the protective atmosphere is a mixture of N2 and H2, wherein the volume percentage of H2 is 10%; the annealing temperature is 950℃ and the time is 4min. Coating: The third annealed plate is coated with a coating to obtain a non-oriented silicon steel plate.

[0040] The magnetic properties of the above-mentioned non-oriented silicon steel sheet are: magnetic induction intensity B50=1.76T, iron loss P1.5 / 50≤4.6W / Kg, iron loss P1.0 / 400≤23.2W / Kg.

[0041] The comparative example uses a single-stage cold rolling method. Because it does not employ a tertiary cold rolling process, the severe plastic deformation caused by the large reduction during cold rolling results in conditions unfavorable for magnetization {111}. <uvw>The recrystallization texture is significantly enhanced, which in turn leads to a sharp deterioration in magnetic properties.

[0042] Comparative Example 2: Steel smelting: The raw materials are smelted to obtain molten steel with the following chemical composition controlled by mass percentage: Si: 1.3%, Al: 0.20%, Mn: 0.30%, P: 0.02%, S: 0.0015%, N: 0.0014%, C: 0.002%, with the remainder being iron and unavoidable impurities; Continuous casting: casting molten steel into a continuous casting billet with a thickness of 220mm; Hot rolling: The continuously cast billet is heated to 1150℃ and held for 1 hour before hot rolling to obtain a hot-rolled plate with a thickness of 2.5mm. First cold rolling annealing: The hot-rolled plate is pickled to remove the surface iron oxide scale, cold rolled to 1.2 mm, and held at 870℃ for 4 min in an atmosphere with a volume ratio of 10% H2 to obtain a first annealed plate; Second cold rolling annealing: After pickling the first annealed plate, it is cold rolled to a thickness of 0.50 mm, and held at 870 °C for 4 min in an atmosphere with a volume ratio of 10% H2 to obtain a second annealed plate with an average grain size of 76 μm. Third cold rolling annealing: After pickling the second annealed plate, it is cold rolled to a final thickness of 0.1 mm; and held at 950°C for 4 min in an atmosphere with a volume ratio of 10% H2. Coating: The third annealed plate is coated with a coating to obtain a non-oriented silicon steel plate.

[0043] The magnetic properties of the above-mentioned non-oriented silicon steel sheet are: magnetic induction intensity B50=1.80T, iron loss P1.5 / 50≤3.1W / Kg, and iron loss P1.0 / 400≤15.4W / Kg.

[0044] As can be seen from the comparative example, when the amount of cold rolling reduction in the third stage is not within the set range, the average grain size of the secondary annealed plate is significantly reduced, and the magnetic properties of the final product plate are also deteriorated.

[0045] In summary, compared with the prior art, the ultra-thin non-oriented silicon steel sheet with high magnetic induction and its preparation method of the present invention have the following advantages and beneficial effects: This invention, under the premise of low Si and Al alloy composition, obtains strong Goss and {001}<0vw> textures in the finished plate through a three-stage cold rolling process. The steel plate exhibits excellent magnetic properties, with ultra-high magnetic induction and low iron loss, solving the problems of difficult manufacturing process and low magnetic properties of existing non-oriented silicon steel ultra-thin strips. It effectively balances the magnetic properties and rollability of non-oriented silicon steel ultra-thin strips. It requires no high-temperature normalizing furnace or the addition of precious metal elements such as Sb or Sn, and has low requirements for production equipment, enabling stable batch production in industrial production.

[0046] It should be noted that, unless otherwise expressly specified and limited, the term "connection" or its synonyms should be interpreted broadly in this document. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, expressions such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Meanwhile, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In addition, "front," "rear," "left," "right," "upper," and "lower" in this document refer to the placement states shown in the accompanying drawings.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.< / uvw> < / uvw> < / uvw> < / uvw>

Claims

1. A method for preparing ultra-thin, non-oriented silicon steel sheets with ultra-high magnetic induction, characterized in that, The method for preparing ultra-thin non-oriented silicon steel sheets with high magnetic induction includes: steel smelting - continuous casting - hot rolling - first cold rolling annealing - second cold rolling annealing - third cold rolling annealing - coating. The chemical composition of the ultra-thin non-oriented silicon steel sheets with high magnetic induction is controlled by mass percentage as follows: Si: 0.5%~1.5%, Al: 0.10%~0.25%, Mn: 0.15%~0.45%, P: 0.02%~0.11%, S≤0.002%, N≤0.002%, C: 0.001%~0.003%, with the remainder being iron and unavoidable impurities. Steel smelting: The process of melting raw materials to obtain molten steel with the target element content; Continuous casting: casting molten steel into continuous casting billets of 200mm~250mm; Hot rolling: The billet is heated to 1100℃~1200℃ in a heating furnace, held for 1h~2h and then hot rolled to obtain a hot-rolled plate with a thickness of 2.0mm~2.8mm. First cold rolling annealing: The hot-rolled plate is pickled to remove the surface iron oxide scale, and then cold-rolled to a thickness of 0.5mm~0.6mm. It is then held at 850℃~900℃ for 2min~5min under a protective atmosphere to obtain the first annealed plate. Second cold rolling annealing: The first annealed plate is pickled to remove the surface iron oxide scale, and the cold rolling reduction rate is controlled at 5%~15%. The plate is then held at 850℃~900℃ for 2min~5min under a protective atmosphere to obtain the second annealed plate. Third cold rolling annealing: The hot-rolled plate is pickled to remove the surface iron oxide scale, and then cold-rolled to a thickness of 0.1mm~0.2mm. It is then held at 900℃~1000℃ for 2min~5min under a protective atmosphere to obtain the third annealed plate. Coating: Apply a coating to the third annealed plate.

2. The method for preparing ultra-thin, non-oriented silicon steel sheets with high magnetic induction as described in claim 1, characterized in that, In the hot rolling process, the final rolling temperature is controlled at 850℃~900℃.

3. The method for preparing ultra-thin, non-oriented silicon steel sheets with high magnetic induction as described in claim 1, characterized in that, In the first cold rolling annealing step, a protective atmosphere of N2 and H2 is used, wherein the volume percentage of H2 is 10% to 50%.

4. The method for preparing ultra-thin, non-oriented silicon steel sheets with high magnetic induction as described in claim 1, characterized in that, In the second cold rolling annealing step, a protective atmosphere of N2 and H2 is used, wherein the volume percentage of H2 is 10% to 50%.

5. The method for preparing ultra-thin, non-oriented silicon steel sheets with high magnetic induction as described in claim 1, characterized in that, In the second cold rolling annealing step, the average grain size is controlled to be 0.6 mm to 1.0 mm.

6. The method for preparing ultra-thin, non-oriented silicon steel sheets with high magnetic induction as described in claim 1, characterized in that, In the third cold rolling annealing step, a protective atmosphere of N2 and H2 is used, wherein the volume percentage of H2 is 10% to 50%.

7. A type of ultra-thin, non-oriented silicon steel sheet with ultra-high magnetic induction, characterized in that, The ultra-high magnetic induction ultra-thin non-oriented silicon steel sheet is produced using the method for preparing ultra-high magnetic induction ultra-thin non-oriented silicon steel sheet as described in any one of claims 1 to 6.

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