High-performance non-oriented silicon steel solid-solution and precipitation synergistically strengthened and preparation method thereof

Abstract

The application discloses a kind of high-performance non-oriented silicon steel of solid solution and precipitation synergistic strengthening and preparation method.The percentage of the chemical composition of the non-oriented silicon steel is as follows:Si 3.0~3.5wt%, Cu0.5~1.5wt%, Al1.1~1.5wt%, Mn1.0~1.5wt%, Ni1.0~2.0wt%, Cr0.6~1.0wt%, (C+N+S+O)≤0.01wt%, the rest is Fe and inevitable inclusion.The high-strength non-oriented silicon steel prepared by the application has a thickness of 0.10~0.5mm, and has high strength and high magnetic performance: magnetic induction intensity B 50 is 1.72~1.75T, P 1.0 / 400 is 11~17W / kg, P 1.0 / 1000 is 41~72W / kg, yield strength R p0.2 ≥750MPa, tensile strength R m ≥830MPa, elongation after fracture ≥7%.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology, specifically relating to a high-performance non-oriented silicon steel with synergistic strengthening by solid solution and precipitation, and its preparation method. Background Technology

[0002] Silicon steel is mainly used as the core of various electric motors, generators and transformers. In recent years, the rapid development of high-end manufacturing such as aerospace and new energy vehicles has put forward higher requirements for the speed of high-speed motors. The rotor speed is as high as tens of thousands or even hundreds of thousands of revolutions per minute. The existing rotor cores made of non-oriented silicon steel have low strength and cannot withstand the huge centrifugal force generated by high-speed rotation [Fan Lifeng, Qin Meimei, Yue Erbin, et al. Technical challenges of new energy vehicles to non-oriented silicon steel [J]. Materials Reports, 2021, 35(15): 15183-15188.][Pan Zhendong, Xiang Li, Zhang Chen, et al. Research progress of high-strength non-oriented electrical steel [J]. Mechanical Engineering Materials, 2014, 38(4): 7-14.]. Therefore, the strength requirement of silicon steel for high-speed drive motors is more than 200 MPa higher than that of traditional non-oriented silicon steel [Gong Jian, Luo Haiwen. Research and progress of high-strength non-oriented silicon steel sheets for drive motors of new energy vehicles [J]. Materials Engineering, 2015, 43(6): 102-112.].

[0003] For a long time, researchers have been dedicated to studying the strengthening methods of non-oriented silicon steel in order to achieve synergistic optimization of the material's mechanical and magnetic properties. The main strengthening mechanisms of non-oriented silicon steel include solid solution strengthening, dislocation and grain refinement strengthening, and precipitation strengthening. Solid solution strengthening research primarily involves adding solid solution strengthening elements such as Si, P, and Cr, but there is an upper limit to the improvement in material strength. Dislocation and grain refinement strengthening usually requires silicon steel to retain a small number of cold-deformed dislocations and small recrystallized grains, but while increasing strength, this leads to a significant increase in iron loss and is prone to anisotropy in magnetic properties. Precipitation strengthening mainly involves adding elements such as Nb, Ti, Cu, and V to control the formation of nano- or micron-sized precipitates in the material, but these precipitates significantly hinder magnetic domain movement, often deteriorating the magnetic properties of non-oriented silicon steel. Therefore, it is difficult to simultaneously achieve both mechanical and magnetic properties by using only one strengthening mechanism. How to achieve the synergistic effect of multiple strengthening mechanisms through the reasonable matching of alloying elements and their contents, and minimize the damage of alloying elements to magnetic properties while improving strength, is one of the key and difficult points in the research and development of high-strength, high-magnetic-induction, and low-iron-loss non-oriented silicon steel. Summary of the Invention

[0004] This invention discloses a high-performance non-oriented silicon steel with synergistic strengthening by solid solution and precipitation, and its preparation method, to solve any of the above-mentioned and other potential problems in the prior art.

[0005] To achieve the above objectives, the technical solution of the present invention is: a high-performance non-oriented silicon steel with synergistic strengthening by solid solution and precipitation, wherein the chemical composition of the non-oriented silicon steel is as follows (mass percentage): Si 3.0wt%~3.5wt%, Cu 0.5wt%~1.5wt%, Al 1.1wt%~1.5wt%, Mn 1.0wt%~1.5wt%, Ni 1.0wt%~2.0wt%, Cr 0.6wt%~1.0wt%, (C+N+S+O) ≤0.01wt%, and the remainder is Fe and unavoidable inclusions.

[0006] Furthermore, the Si / Cu ratio in the chemical composition of the non-oriented silicon steel is 2.5~4.5:1; the non-oriented silicon steel has nano-precipitates with a size of 2~10nm.

[0007] Another objective of this invention is to provide a method for preparing high-performance non-oriented silicon steel with synergistic strengthening through solid solution and precipitation, the method specifically comprising the following steps:

[0008] S1) Vacuum smelting: Raw materials with a purity of 99.99% or higher are weighed according to the design ratio and smelted in a vacuum environment to obtain non-oriented silicon steel molten steel;

[0009] S2) Casting, hot forging and hot rolling: S1) non-oriented silicon steel molten steel is cast into ingots, demolded and air-cooled, and after repeated upsetting and drawing, it is forged into square billets. After being heated to a certain temperature and held at that temperature, it is hot-rolled to obtain hot-rolled plates.

[0010] S3) Normalizing heat treatment: The hot-rolled sheet obtained in S2) is subjected to normalizing heat treatment to obtain a normalized sheet;

[0011] S4) Pickling and warm rolling: The normalized plate obtained in S2) is cleaned in hydrochloric acid, heated and then subjected to multiple warm rolling passes to obtain a rolled plate with a thickness of 0.1~0.5mm.

[0012] S5) Recrystallization annealing: The rolled plate obtained in S4) is subjected to recrystallization annealing under an inert atmosphere, and then rapidly cooled to obtain an annealed plate;

[0013] S6) Aging heat treatment: The annealed plate obtained in S5) is aged in an inert atmosphere and then rapidly cooled to obtain high-performance non-oriented silicon steel with synergistic strengthening of solution and precipitation.

[0014] Furthermore, S4) can also be: first heating and rolling the pickled normalized plate multiple times to a thickness of 0.5~0.7mm, and then cold rolling it at room temperature to a thickness of 0.1~0.5mm.

[0015] Furthermore, in S1), the vacuum smelting is carried out under vacuum conditions not exceeding 12 Pa for more than 45 minutes, and the smelting temperature is 1400~1600℃.

[0016] The forging method in S2) is mechanical free forging, and the forging temperature is 950~1150℃;

[0017] The heating temperature is 1000~1200℃, the holding time is 30~120min, the hot rolling thickness is 2~3mm, and the final rolling temperature is not lower than 850℃.

[0018] Furthermore, the normalizing heat treatment process in S3) has a temperature of 850~1050℃ and a normalizing time of 1~5min;

[0019] The hydrochloric acid concentration for pickling in S4 is 10-20%, the temperature for warm rolling is 300-400℃, and the holding time is 5-10 minutes.

[0020] Furthermore, the annealing temperature in S5) is 900~1100℃, the annealing time is 5~15min, followed by rapid cooling.

[0021] The aging temperature in S6 is 500~600℃, and the aging time is 2~16h.

[0022] Furthermore, the inert atmosphere in S5) and S6) is Ar.

[0023] Furthermore, the magnetic induction intensity B of the non-oriented silicon steel 50 The value is 1.72~1.75T, P 1.0 / 400 The concentration is 11~17 W / kg, P 1.0 / 1000 The yield strength is 41~72 W / kg, and the yield strength R is... p0.2 ≥750MPa, tensile strength R m ≥830MPa, elongation after fracture ≥7%.

[0024] A non-oriented silicon steel, which is prepared by the above-described preparation method.

[0025] The principle of this invention is as follows: Excessive Si and Cu in the composition will lead to a decrease in magnetic induction and an increase in rolling deformation resistance. The Si / Cu ratio is controlled at 2.5~4.5:1. (2) By adding Ni and Cu to form nanoscale precipitates, Ni can effectively promote the precipitation of Cu-rich nanophases and hinder the coarsening of precipitates. The size of the precipitates can be controlled at 2~10nm, which is smaller than the magnetic domain wall thickness (30~100nm), so precipitation strengthening can be achieved without significantly increasing iron loss. (3) Ni dissolved in the matrix and the added Mn and Cr elements form a solid solution strengthening effect. (4) Mn and Cr elements improve the texture of silicon steel while forming solid solution strengthening. The addition of Mn increases the (100) and (110) crystal planes that are beneficial to magnetic properties in the microstructure and reduces the (111) crystal plane that is detrimental to magnetic properties, thus significantly improving the magnetic properties. The addition of Cr can suppress the recovery of hot-rolled microstructure, increase the fraction of texture that is beneficial to magnetic properties after normalization, and improve the magnetic properties.

[0026] The beneficial effects of this invention are: due to the adoption of the above technical solution, the preparation process of this invention is simple, and the obtained high-performance non-oriented silicon steel strip with a thickness of 0.1~0.5mm, while achieving a yield strength of 750MPa or higher, also possesses excellent magnetic properties: magnetic induction intensity B 50 The value is 1.72~1.75T, P 1.0 / 400 It is 11~17W / kg; using As a comprehensive performance evaluation index, the evaluation indices of the three thickness specifications of high-performance non-oriented silicon steel strip of this invention are 112.8, 90.2, and 78.2, respectively. Compared with other solution-strengthened non-oriented silicon steels, the comprehensive performance is improved by 9% to 25%. The raw material cost of the high-performance non-oriented silicon steel of this invention is approximately 8700 to 9100 yuan / ton, and the same strength grade (R... p0.2 The raw material cost of other non-oriented silicon steel (≥700MPa grade) is about RMB 9300~10750 / ton. This invention has lower raw material cost and better comprehensive performance. Attached Figure Description

[0027] Figure 1 This is a flowchart of a method for preparing high-performance non-oriented silicon steel with synergistic strengthening through solid solution and precipitation, according to the present invention.

[0028] Figure 2 This is a schematic diagram of the metallographic microstructure of the aged strip in Example 1, prepared using the method of the present invention;

[0029] Figure 3 This is a schematic diagram of the metallographic microstructure of the aged strip in Example 2, prepared using the method of the present invention;

[0030] Figure 4This is a schematic diagram of the metallographic microstructure of the aged strip in Example 3, prepared using the method of the present invention;

[0031] Figure 5 This is a schematic diagram of the precipitated phase morphology of the aged strip in Example 1, prepared using the method of the present invention;

[0032] Figure 6 This is a schematic diagram of the tensile stress-strain curve of the medium-aged strip prepared using the method of the present invention. Detailed Implementation

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] like Figure 1 As shown, this invention discloses a method for preparing high-performance non-oriented silicon steel with synergistic strengthening through solid solution and precipitation. The method specifically includes the following steps:

[0035] S1) Vacuum smelting: Raw materials with a purity of 99.99% or higher are weighed according to the design ratio and smelted in a vacuum environment to obtain non-oriented silicon steel molten steel;

[0036] S2) Casting, hot forging and hot rolling: S1) non-oriented silicon steel molten steel is cast into ingots, demolded and air-cooled, and after repeated upsetting and drawing, it is forged into square billets. After being heated to a certain temperature and held at that temperature, it is hot-rolled to obtain hot-rolled plates.

[0037] S3) Normalizing heat treatment: The hot-rolled sheet obtained in S2) is subjected to normalizing heat treatment to obtain a normalized sheet;

[0038] S4) Pickling and warm rolling: The normalized plate obtained in S2) is cleaned in hydrochloric acid, heated and then subjected to multiple warm rolling passes to obtain a rolled plate with a thickness of 0.1~0.5 mm.

[0039] S5) Recrystallization annealing: The rolled plate obtained in S4) is subjected to recrystallization annealing under an inert atmosphere, and then rapidly cooled to obtain an annealed plate;

[0040] S6) Aging heat treatment: The annealed plate obtained in S5) is aged in an inert atmosphere and then rapidly cooled to obtain high-performance non-oriented silicon steel with synergistic strengthening of solution and precipitation.

[0041] Example 1: FeSi 3.4 Al 1.2 Mn 1.0 Ni 1.5 Cr 0.7 Cu 0.8 Non-oriented silicon steel

[0042] The specific steps are as follows:

[0043] (1) Vacuum smelting: Using raw materials with a purity of 99.99% or higher, the mixed raw materials were smelted in a vacuum induction furnace. Vacuum degassing was carried out for 45 min under a vacuum of 12 Pa, and the smelting temperature was 1530 ℃. Non-oriented silicon steel molten steel was obtained. Its composition by percentage is Si 3.4 wt%, Ni 1.5 wt%, Al 1.2 wt%, Mn 1.0 wt%, Cu 0.8 wt%, Cr 0.7 wt%, (C+N+S+O)≤0.01 wt%.

[0044] (2) Casting, hot forging and hot rolling: Molten non-oriented silicon steel is cast into ingots, demolded and air-cooled. Mechanical free forging is used, with a forging temperature of 1150 ℃, and repeated upsetting and drawing 10 times to forge the ingot into a square billet. The square billet is then heated to 1150 ℃ in the furnace and held for 60 min before being hot-rolled to a thickness of 2.5 mm with a reduction rate of 86% and a final rolling temperature of 950 ℃.

[0045] (3) Normalizing heat treatment: The hot-rolled plate was subjected to normalizing heat treatment at 950 °C and the normalizing time was controlled to be 3 min.

[0046] (4) Pickling and warm rolling: After cleaning the normalized plate in 15% hydrochloric acid, it is kept at 400 ℃ for 8 min and then warm rolled in multiple passes to 0.35 mm with a reduction rate of 86%. The plate is kept warm for 2 min between each pass.

[0047] (5) Recrystallization annealing: The 0.35 mm thick warm rolled plate was recrystallized and annealed under Ar atmosphere. The annealing temperature was 1000 ℃ and the annealing time was 10 min, followed by rapid cooling.

[0048] (6) Aging heat treatment: The annealed plate is aged under vacuum conditions at an aging temperature of 550 ℃ for 4 hours to allow the precipitated phases to fully precipitate. It is then rapidly cooled to obtain an aged strip of non-oriented silicon steel. A schematic diagram of the metallographic microstructure of the aged strip is shown below. Figure 2 As shown; schematic diagram of the precipitated phase morphology in aged strip material, as follows. Figure 5 As shown; the tensile stress-strain curve of the aged strip, as follows. Figure 6 As shown.

[0049] In the specific implementation process, when testing the performance of high-performance non-oriented silicon steel, the magnetic properties of a single sheet of non-oriented silicon steel are measured using an SST-50 testing device. Iron loss P 1.0 / 400 The total loss and iron loss P are measured at a magnetic polarization intensity of 1.0 T under an alternating magnetic field with a frequency of 400 Hz. 1.0 / 1000 The total loss is measured at 1.0 T for an alternating magnetic field with a frequency of 1000 Hz and a magnetic polarization intensity of 1.0 T. Magnetic induction B50 The magnetic polarization intensity is measured under a magnetic field strength of 5000 A / m.

[0050] In this embodiment of the invention, the tensile test was conducted at room temperature according to the national standard GB / T 228.1-2010.

[0051] The high-strength non-oriented silicon steel aging strip manufactured using the above process has excellent surface quality and a high magnetic induction intensity B of the finished product. 50 The iron loss value P is 1.75 ± 0.02 T. 1.0 / 400 It is 17.0 ± 0.3 W / kg; iron loss value P 1.0 / 1000 The yield strength is 71.8 ± 2.0 W / kg, and the yield strength R is... p0.2 The tensile strength is 760±4 MPa, and the tensile strength R is... m The strength was 860±17 MPa, and the elongation after fracture (A) was 8.3±0.6%.

[0052] Example 2: FeSi 3.5 Al 1.1 Mn 1.0 Ni 1.1 Cr 0.8 Cu 1.3 Non-oriented silicon steel

[0053] In this implementation example, a method for preparing high-performance non-oriented silicon steel with synergistic strengthening through solid solution and precipitation is described in the following steps:

[0054] (1) Vacuum smelting: Using raw materials with a purity of 99.99% or higher, the mixed raw materials were smelted in a vacuum induction furnace. Vacuum degassing was performed for 45 min under a vacuum of 12 Pa, and the smelting temperature was 1530 ℃. Non-oriented silicon steel molten steel was obtained. Its composition by percentage is Si 3.5 wt%, Ni 1.1 wt%, Al 1.1 wt%, Mn 1.0 wt%, Cu 1.3 wt%, Cr 0.8 wt%, (C+N+S+O)≤0.01 wt%.

[0055] (2) Casting, hot forging and hot rolling: Molten non-oriented silicon steel is cast into ingots, demolded and air-cooled. Mechanical free forging is used, with a forging temperature of 1150 ℃, and repeated upsetting and drawing 10 times to forge the ingot into a square billet. The square billet is then heated to 1150 ℃ in the furnace and held for 60 min before being hot-rolled to a thickness of 2.5 mm with a reduction rate of 86% and a final rolling temperature of 950 ℃.

[0056] (3) Normalizing heat treatment: The hot-rolled plate was subjected to normalizing heat treatment at 950 °C and the normalizing time was controlled to be 3 min.

[0057] (4) Pickling and warm rolling: After cleaning the normalized plate in 15% hydrochloric acid, it is kept at 400 ℃ for 8 min and warm rolled in multiple passes to 0.3 mm with a reduction rate of 88%. The plate is kept warm for 2 min between each pass.

[0058] (5) Recrystallization annealing: The 0.3 mm thick warm rolled plate was recrystallized and annealed under Ar atmosphere. The annealing temperature was 1000 ℃ and the annealing time was 10 min, followed by rapid cooling.

[0059] (6) Aging heat treatment: The annealed plate is aged under vacuum conditions at an aging temperature of 550 ℃ for 4 hours to allow the precipitated phases to fully precipitate. It is then rapidly cooled to obtain an aged strip of non-oriented silicon steel. A schematic diagram of the metallographic microstructure of the aged strip is shown below. Figure 3 As shown; the tensile stress-strain curve of the aged strip, as follows. Figure 6 As shown.

[0060] The high-strength non-oriented silicon steel aging strip manufactured using the above process has excellent surface quality and a high magnetic induction intensity B of the finished product. 50 The iron loss value P is 1.73 ± 0.01 T. 1.0 / 400 It is 14.5 ± 0.4 W / kg; iron loss value P 1.0 / 1000 The yield strength is 60.7 ± 2.1 W / kg, and the yield strength R is... p0.2 The tensile strength is 756±6 MPa, and the tensile strength R is... m The strength was 840±9 MPa, and the elongation after fracture (A) was 7.8±1.1%.

[0061] Example 3: FeSi 3.2 Al 1.1 Mn 1.3 Ni 1.5 Cr 0.6 Cu 1.2 Non-oriented silicon steel

[0062] In this implementation example, a method for preparing high-performance non-oriented silicon steel with synergistic strengthening through solid solution and precipitation is described in the following steps:

[0063] (1) Vacuum smelting: Using raw materials with a purity of 99.99% or higher, the mixed raw materials were smelted in a vacuum induction furnace. Vacuum degassing was performed for 45 min under a vacuum of 12 Pa, and the smelting temperature was 1530 ℃. Non-oriented silicon steel molten steel was obtained. Its composition by percentage is Si 3.2 wt%, Ni 1.5 wt%, Al 1.1 wt%, Mn 1.3 wt%, Cu 1.2 wt%, Cr 0.5 wt%, (C+N+S+O)≤0.01 wt%.

[0064] (2) Casting, forging and hot rolling: Molten non-oriented silicon steel is cast into ingots, demolded and air-cooled. Mechanical free forging is used, with a forging temperature of 1150 ℃, and repeated upsetting and drawing 10 times to forge the ingot into a square billet. The billet is then heated to 1150 ℃ in the furnace and held for 60 min before hot rolling to a thickness of 2.5 mm, with a reduction rate of 86%, and a final rolling temperature of 950 ℃.

[0065] (3) Normalizing heat treatment: The hot-rolled plate was subjected to normalizing heat treatment at 950 °C and the normalizing time was controlled to be 3 min.

[0066] (4) Pickling and warm rolling: After cleaning the normalized plate in 15% hydrochloric acid, it is kept at 400 ℃ for 8 min and warm rolled in multiple passes to 0.5 mm with a reduction rate of 80%. The plate is kept at 2 min between each pass and then cold rolled in multiple passes at room temperature to 0.2 mm with a reduction rate of 60%.

[0067] (5) Recrystallization annealing: The 0.2 mm thick warm rolled plate was recrystallized and annealed under Ar atmosphere. The annealing temperature was 1000 ℃ and the annealing time was 10 min, followed by rapid cooling.

[0068] (6) Aging heat treatment: The annealed plate is aged under vacuum conditions at an aging temperature of 550 ℃ for 4 hours to allow the precipitated phases to fully precipitate. It is then rapidly cooled to obtain an aged strip of non-oriented silicon steel. A schematic diagram of the metallographic microstructure of the aged strip is shown below. Figure 4 As shown; the tensile stress-strain curve of the aged strip, as follows. Figure 6 As shown.

[0069] The high-strength non-oriented silicon steel aging strip manufactured using the above process has excellent surface quality and a high magnetic induction intensity B of the finished product. 50 The iron loss value P is 1.73 ± 0.02 T. 1.0 / 400 It is 11.5 ± 0.3 W / kg; iron loss value P 1.0 / 1000 The yield strength is 43.4 ± 2.0 W / kg, and the yield strength R is... p0.2 The tensile strength is 750±18 MPa, and the tensile strength R is... m The strength was 830±6 MPa, and the elongation after fracture (A) was 7.5±0.9%.

[0070] The foregoing has provided a detailed description of a high-performance non-oriented silicon steel with synergistic strengthening through solid solution and precipitation, and its preparation method, as provided in the embodiments of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this application; furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

[0071] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The terms "comprising" and "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising / including but not limited to". "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error. The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of illustrating the general principles of this application and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0072] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0073] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0074] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application 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 application 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 this application should be within the protection scope of the appended claims.

[0075] There are three possibilities: A and B exist simultaneously, B exists alone, and so on. Additionally, the character " / " in this text generally indicates that the preceding and following objects have an "OR" relationship.

[0076] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application 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 application 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 this application should be within the protection scope of the appended claims.

Claims

1. A method for preparing high-performance non-oriented silicon steel with synergistic strengthening through solid solution and precipitation, characterized in that, The chemical composition (mass percentage) of high-performance non-oriented silicon steel with synergistic strengthening through solid solution and precipitation is as follows: Si 3.0 wt%~3.5 wt%, Cu 0.5 wt%~1.5 wt%, Al 1.1 wt%~1.5 wt%, Mn 1.0 wt%~1.5 wt%, Ni 1.0 wt%~2.0 wt%, Cr 0.6 wt%~1.0 wt%, (C+N+S+O) ≤0.01 wt%, with the remainder being Fe and unavoidable inclusions; The Si / Cu ratio in the chemical composition of the non-oriented silicon steel is 2.5~4.5:1; the non-oriented silicon steel has nano-precipitates with a size of 2~10 nm. The preparation method specifically includes the following steps: S1) Vacuum smelting: Raw materials with a purity of 99.99% or higher are weighed according to the design ratio and smelted in a vacuum environment to obtain non-oriented silicon steel molten steel; S2) Casting, hot forging and hot rolling: S1) non-oriented silicon steel molten steel is cast into ingots, demolded and air-cooled, and after repeated upsetting and drawing, it is forged into square billets. After being heated to a certain temperature and held at that temperature, it is hot-rolled to obtain hot-rolled plates. S3) Normalizing heat treatment: The hot-rolled sheet obtained in S2) is subjected to normalizing heat treatment to obtain a normalized sheet; S4) Pickling and warm rolling: After cleaning the normalized plate obtained in S3) in hydrochloric acid, it is heated and then subjected to multiple warm rolling passes to obtain a rolled plate with a thickness of 0.1~0.5 mm. S5) Recrystallization annealing: The rolled plate obtained in S4) is subjected to recrystallization annealing under an inert atmosphere, and then rapidly cooled to obtain an annealed plate; S6) Aging heat treatment: The annealed plate obtained in S5) is aged in an inert atmosphere and then rapidly cooled to obtain high-performance non-oriented silicon steel with synergistic strengthening of solution and precipitation. In S5), the annealing temperature is 900~1100 ℃, the annealing time is 5~15 min, and then rapid cooling is performed. The aging temperature in S6 is 500~600 ℃, and the aging time is 2~16 h.

2. The method for preparing high-performance non-oriented silicon steel with synergistic strengthening through solid solution and precipitation according to claim 1, characterized in that, S4) can also be: first heating and rolling the pickled normalized plate multiple times to a thickness of 0.5~0.7 mm, and then cold rolling it at room temperature to a thickness of 0.1~0.5 mm.

3. The method for preparing high-performance non-oriented silicon steel with synergistic strengthening through solid solution and precipitation according to claim 1, characterized in that, The vacuum smelting in S1) is carried out under vacuum conditions not exceeding 12 Pa for more than 45 minutes, and the smelting temperature is 1400~1600 ℃. The forging method in S2) is mechanical free forging, and the forging temperature is 950~1150 ℃; The heating temperature is 1000~1200 ℃, the holding time is 30~120 min, the hot rolling thickness is 2~3 mm, and the final rolling temperature is not lower than 850 ℃.

4. The method for preparing high-performance non-oriented silicon steel with synergistic strengthening by solid solution and precipitation according to claim 1, characterized in that, The normalizing heat treatment process in S3) is as follows: the temperature is 850~1050 ℃, and the normalizing time is 1~5 min; The hydrochloric acid concentration for pickling in S4 is 10-20%, the temperature for warm rolling is 300-400 ℃, and the holding time is 5-10 min.

5. The method for preparing high-performance non-oriented silicon steel with synergistic strengthening by solid solution and precipitation according to claim 1, characterized in that, The inert atmosphere in S5) and S6) is Ar.

6. The method for preparing high-performance non-oriented silicon steel with synergistic strengthening by solution treatment and precipitation according to claim 1, characterized in that, The magnetic induction intensity B of the non-oriented silicon steel 50 The values ​​are 1.72~1.75 T, P 1.0 / 400 The value is 11~17 W / kg, P 1.0 / 1000 The yield strength is 41~72 W / kg, and the yield strength R is... p0.2 ≥750 MPa, tensile strength R m ≥830 MPa, elongation after fracture ≥7%.

7. A non-oriented silicon steel, characterized in that, The non-oriented silicon steel is prepared by the method for preparing high-performance non-oriented silicon steel with synergistic strengthening of solid solution and precipitation as described in any one of claims 1-6.

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