A method for preparing a silicon steel laminated composite plate with excellent magnetic properties
By alternately stacking 1%Si and 3%Si non-oriented silicon steel and performing hot rolling composite, large deformation cold rolling and recrystallization annealing, the problem of balancing high magnetic properties and high mechanical properties of non-oriented silicon steel was solved, and a silicon steel layered composite plate with excellent magnetic properties and high strength was prepared, which is suitable for the high-performance material requirements of new energy vehicle motors and other applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI INST OF TECH
- Filing Date
- 2026-03-11
- Publication Date
- 2026-06-09
AI Technical Summary
Existing non-oriented silicon steels struggle to achieve both high magnetic properties and high mechanical properties, especially in the preparation of thin-gauge composite plates where cold rolling is difficult and mechanical properties are insufficient.
Alternating stacking of 1%Si non-oriented silicon steel and 3%Si non-oriented silicon steel, followed by hot rolling and large deformation cold rolling, and recrystallization annealing at 650℃, optimizes the microstructure and texture, forming a silicon steel layered composite plate with high magnetic induction and high strength.
Thin-gauge silicon steel layered composite plates with a thickness of ≤0.70mm were prepared, with a magnetic induction of 1.704~1.71T and a yield strength of 367~400MPa, achieving an excellent match between high magnetic properties and high mechanical properties, which is suitable for fields such as new energy vehicle motors.
Smart Images
Figure CN122164747A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of non-oriented silicon steel production technology, and in particular to a method for preparing a silicon steel layered composite plate with excellent magnetic properties. Background Technology
[0002] Non-oriented silicon steel is the core material for the cores of electrical equipment such as motors and transformers, and its performance directly determines the energy efficiency level of these devices. With the rapid development of new energy vehicles, high-efficiency industrial motors, and other fields, there are dual requirements for non-oriented silicon steel: high magnetic properties (high magnetic induction, low iron loss) and high mechanical properties (high strength).
[0003] However, non-oriented silicon steel with a single silicon content struggles to achieve both of these performance characteristics. 1% Si non-oriented silicon steel is a low-silicon alloy steel with good plasticity and processing properties, and excellent mechanical properties, but its magnetic properties are poor, particularly in reducing iron loss and improving magnetic permeability. With the increasing demand for higher-performance power equipment, the application of 1% Si non-oriented silicon steel in the domestic market is gradually being challenged by high-silicon content silicon steel. 3.0% Si non-oriented silicon steel is a high-silicon alloy steel with excellent magnetic properties, higher magnetic permeability, and lower iron loss, making it suitable for high-frequency applications. However, its mechanical properties are relatively poor; the increased silicon content leads to increased brittleness, limiting its use in applications with high mechanical stress. Cold rolling is difficult, and its yield strength is low, making it difficult to meet the requirements of certain high-stress applications.
[0004] Therefore, developing a method for preparing thin-gauge, high-magnetic-performance, and high-strength silicon steel layered composite plates has significant industrial application value. Summary of the Invention
[0005] The purpose of this invention is to overcome the above-mentioned defects. In view of the problems that it is difficult for non-oriented silicon steel with a single silicon content in the prior art to take into account both magnetic and mechanical properties, and that it is difficult for existing composite plate technology to prepare thin-gauge (below 0.70mm) high-silicon / low-silicon composite plates, this invention provides a method for preparing silicon steel layered composite plates with excellent comprehensive performance, as well as silicon steel layered composite plates prepared by this method.
[0006] To achieve the above objectives, this invention proposes a method for preparing a layered composite plate of silicon steel with superior magnetic properties. This method involves hot-rolling 1% Si non-oriented silicon steel with superior mechanical properties and 3% Si non-oriented silicon steel with high magnetic permeability, complementing the advantages of the two materials to obtain a layered metal composite material with higher mechanical and magnetic properties. The magnetic properties of the composite material are mainly controlled by the recrystallization grain size and recrystallization texture. Cold rolling and annealing processes are key steps in determining the microstructure and texture of the steel strip. The method of this invention optimizes the microstructure and texture strength of the non-oriented silicon steel through cold rolling and annealing processes while ensuring magnetic properties, helping to solve the current problem of strength limitations for non-oriented silicon steel used in new energy vehicle motors and improving resource utilization.
[0007] The preparation method includes the following steps: S1: Alternately stack 1%Si non-oriented silicon steel sheets and 3%Si non-oriented silicon steel sheets, with the 3%Si non-oriented silicon steel sheet on the outermost side, to form a layered stack; S2: Vacuum sealing process is performed on the layered stack; S3: The layered stacked body after vacuum sealing is hot rolled together at a temperature of 780℃~850℃ and a total reduction rate of 75%~85% to obtain a hot rolled composite plate. S4: The hot-rolled composite plate is cold-rolled with a cold rolling reduction rate of 50%~75% to obtain a cold-rolled composite plate; S5: The cold-rolled composite plate is subjected to recrystallization annealing at a temperature of 600℃~700℃ and a holding time of 60 minutes to obtain a silicon steel layered composite plate with a magnetic induction greater than 1.70T and a yield strength greater than 360MPa.
[0008] Furthermore, in the layered stack, the 1.0% Si non-oriented silicon steel plate and the 3.0% Si non-oriented silicon steel plate have the same length, width and thickness, and the total number of layers in the layered stack formed by the alternating stacking of the two is an odd number of layers, and the number of layers of the 3% non-oriented silicon steel layer is one more than the number of layers of the 1% non-oriented silicon steel layer.
[0009] Furthermore, in step S2, the vacuum sealing process specifically involves placing the layered stacked body into a 304 stainless steel square tube with a boron nitride coating on the inner wall, inserting 304 stainless steel plugs into both ends of the square tube, welding and sealing it, then evacuating to 1 Pa and filling it with argon gas for protection.
[0010] Furthermore, the specific process of the hot-rolled composite is as follows: heating at 800℃ for 1 hour, performing two rolling passes, with a total reduction rate of 80%, to obtain a hot-rolled composite plate with a thickness of 2.0~2.1mm.
[0011] Furthermore, in step S4, the thickness of the cold-rolled composite plate is 0.60~0.70mm.
[0012] Furthermore, the hot rolling temperature is 800℃, the total hot rolling reduction rate is 80%, the cold rolling reduction rate is 70%, and the annealing temperature is 650℃.
[0013] The present invention also proposes a silicon steel layered composite plate with excellent magnetic properties, which is prepared by the above-mentioned method for preparing silicon steel layered composite plate with excellent magnetic properties. The thickness of the silicon steel layered composite plate is 0.70 mm or less, the magnetic induction is 1.704~1.71T, and the yield strength is 367~400MPa.
[0014] The technical solution of this invention is based on the following principles and discoveries: First, this invention employs an odd-numbered stacking structure design with "high silicon on the outside," placing the high-silicon layer (3% Si non-oriented silicon steel) on the outer side. This directly ensures excellent magnetic properties. The 3% Si high-silicon layer has high permeability and low iron loss, with magnetic flux mainly flowing through the surface high-silicon region. This fully utilizes the excellent soft magnetic properties of the high-silicon steel, giving the composite plate high magnetic induction. Although this increases the difficulty of hot-rolling composite, it creates favorable conditions for subsequent cold rolling. During hot-rolling composite, the 3% Si high-silicon layer on the outside undergoes greater plastic deformation, resulting in a certain degree of refinement and homogenization of its microstructure. Simultaneously, it forms a metallurgical bond with the mechanically strong low-silicon layer (1% Si non-oriented silicon steel), improving the plasticity of the high-silicon layer and enabling it to withstand subsequent large-deformation cold rolling. The use of a symmetrical multi-layer structure reduces plate warping and internal stress. The odd-numbered layer stacking ensures that the composite plate is symmetrical from top to bottom, with high-silicon layers on both sides. This results in uniform stress distribution during hot rolling, cold rolling, and annealing, leading to a straight plate shape and uniform and stable magnetic properties.
[0015] Secondly, this process employs a two-step large deformation rolling strategy: hot rolling followed by cold rolling. Hot rolling utilizes an 80% high-pressure reduction rate, thinning the initially thin slab to 2.0-2.1 mm in a single composite process, while simultaneously achieving a strong metallurgical bond between the high and low silicon steel interfaces, ensuring the overall formation of the composite plate. Cold rolling uses a 70% high-pressure reduction rate, further thinning the composite plate to a minimum thickness of 0.60-0.70 mm. This process also introduces large deformation energy storage, providing sufficient nucleation driving force for subsequent recrystallization annealing, effectively controlling grain size and texture, ultimately resulting in a thin-gauge layered composite plate with both high magnetic induction and high strength. The mechanism of these two large deformation steps is as follows: the large deformation of hot rolling establishes the initial deformation structure and substructure for the high-silicon layer, resulting in a moderate degree of work hardening; the large deformation of cold rolling further accumulates deformation energy storage, providing driving force for subsequent recrystallization annealing, while simultaneously promoting the formation of a favorable texture (λ-fiber texture).
[0016] Finally, this invention employs a medium-temperature recrystallization annealing at 650℃ for 60 minutes. This temperature precisely overlaps with the recrystallization temperatures of 1.0% Si and 3.0% Si materials. At this temperature, the high-density dislocations and deformation energy introduced by cold rolling provide sufficient driving force for recrystallization, ensuring complete recrystallization of both the high-silicon and low-silicon layers: For the 3% Si high-silicon surface layer: sufficient recrystallization and moderate grain growth are beneficial for forming strong Gaussian and cubic textures, significantly improving magnetic permeability and magnetic induction, and reducing iron loss. For the 1% Si low-silicon core layer: after recrystallization, the grains are refined and uniform, without abnormal growth, maintaining high yield strength and processing performance. Simultaneously, 650℃ avoids excessive diffusion of interface elements, blurred layered structures, and deterioration of magnetic properties caused by excessively high temperatures, and also avoids incomplete recrystallization, high residual stress, and low magnetic properties caused by excessively low temperatures. By precisely annealing at 650℃, texture optimization, controllable grain size, and interface stability are achieved, ultimately endowing the silicon steel layered composite plate with excellent magnetic and mechanical properties.
[0017] Through the synergistic effect of the above-mentioned technical features, thin-gauge silicon steel layered composite plates with a thickness of ≤0.70mm were successfully prepared, with a magnetic induction of 1.704~1.71T and a yield strength of 367~400MPa, achieving an excellent match between high magnetic properties and high mechanical properties.
[0018] Compared with the prior art, the advantages of the present invention are: This invention successfully prepared thin-gauge silicon steel layered composite plates with a thickness of 0.60~0.70mm by alternately stacking 1%Si non-oriented silicon steel plates and 3%Si non-oriented silicon steel plates, with the high silicon layer located on the outermost side, and combining hot rolling composite, large deformation cold rolling and recrystallization annealing processes, thus overcoming the problem of cold rolling cracking of the high silicon layer.
[0019] The silicon steel layered composite plate prepared by this invention has a magnetic induction of 1.704~1.71T and a yield strength of 367~400MPa, achieving an excellent match between high magnetic properties and high mechanical properties, which is superior to single silicon steel materials.
[0020] The method of this invention is simple and easy to industrialize, and can be applied to fields with high requirements for material performance, such as new energy vehicle motors.
[0021] This invention involves hot-rolling a composite of 1% and 3% non-oriented silicon steel sheets to obtain a layered silicon steel composite plate. Subsequent cold rolling, with a higher cold rolling reduction rate, results in greater plastic deformation and more pronounced grain rearrangement, ultimately leading to texture enhancement. Finally, an annealing process is used to obtain a suitable average grain size and good λ-fiber texture, increasing the beneficial texture content of the 1% non-oriented silicon steel and the strength of the 3% non-oriented silicon steel, resulting in excellent magnetic and mechanical properties.
[0022] The method of this invention can achieve a dense interface between high-silicon and low-silicon layers with fewer defects and high bonding strength, effectively improving the interlayer deformation coordination. During cold rolling, it can significantly suppress cracking of the high-silicon layer and achieve precise control of microstructure and texture. It is more suitable for the stable preparation of thin-gauge, high-precision composite plates with good dimensional uniformity and high yield. The resulting silicon steel layered composite material can simultaneously achieve excellent magnetic properties and high strength. The process is simple, highly controllable, and more suitable for industrial mass production. Attached Figure Description
[0023] Figure 1 This is a process flow diagram for preparing a silicon steel layered composite plate with excellent magnetic properties, as proposed in an embodiment of the present invention.
[0024] Figure 2 Microstructure diagram of the finished hot-rolled layered composite plate prepared in step S3 of the method in this embodiment.
[0025] Figure 3 The macroscopic texture diagram of the finished hot-rolled layered composite plate prepared in step S3 of this embodiment: a is the high-silicon layer; b is the low-silicon layer.
[0026] Figure 4 Microstructure diagram of the finished cold-rolled layered composite plate prepared in step S4 of the method in this embodiment.
[0027] Figure 5 Macroscopic texture diagram of the finished cold-rolled layered composite plate prepared in step S4 of this embodiment: a is the high-silicon layer; b is the low-silicon layer.
[0028] Figure 6 Microstructure of the finished annealed layered composite plate prepared in step S5 of this embodiment.
[0029] Figure 7 Macroscopic texture diagram of the finished annealed layered composite plate prepared in step S5 of this embodiment: a is the high silicon layer; b is the low silicon layer.
[0030] Figure 8 The following are microstructure images of samples with different cold rolling reduction rates in Comparative Example 1: (a) is the microstructure image of the sample with a cold rolling reduction rate of 30%, (b) is the microstructure image of the sample with a cold rolling reduction rate of 50%, and (c) is the microstructure image of the sample with a cold rolling reduction rate of 70%.
[0031] Figure 9 Macroscopic texture diagrams of samples with different cold rolling reduction rates in Comparative Example 1: (a) CR30%-H, (b) CR50%-H, and (c) CR70%-H are high-silicon layers; (d) CR30%-L, (e) CR50%-L, and (f) CR70%-L are low-silicon layers.
[0032] Figure 10 The following are microstructure images of samples with different hot rolling reduction rates in Comparative Example 2: (a) is the microstructure image of the sample with a hot rolling temperature of 950℃ and a total reduction rate of 90%, and (b) is the microstructure image of the sample with a hot rolling temperature of 800℃ and a total reduction rate of 80%.
[0033] Figure 11 The macroscopic texture diagrams of samples with different hot rolling reduction rates in Comparative Example 2 are as follows: (a) is the HR950℃-90%-H high silicon layer, (b) is the HR950℃-90%-L low silicon layer, (c) is the HR800℃-80%-H high silicon layer, and (d) is the HR800℃-80%-L low silicon layer. Detailed Implementation
[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be further described below.
[0035] This embodiment proposes a method for preparing a silicon steel layered composite plate with excellent magnetic properties, such as... Figure 1 As shown, the method includes the following steps: S1: Alternately stack 1%Si non-oriented silicon steel sheets and 3%Si non-oriented silicon steel sheets, with the 3%Si non-oriented silicon steel sheet on the outermost side, to form a layered stack; The specific implementation method for this step is as follows: S1.1 Layer Design The total number of layers in the layered stack formed by alternating layers of 1% and 3% non-oriented silicon steel is an odd number, with the 3% non-oriented silicon steel layer having one more layer than the 1% non-oriented silicon steel layer and being located on the outermost side. In this embodiment, the total number of layers in the layered stack formed by 1% and 3% non-oriented silicon steel is designed to be 21, with 11 layers of 3% non-oriented silicon steel and 10 layers of 1% non-oriented silicon steel.
[0036] S1.2 Selection of Board Material The selected 1.0% Si non-oriented silicon steel sheets and 3.0% Si non-oriented silicon steel sheets must have the same length, width, and thickness. In this embodiment, the length, width, and thickness of the 1% non-oriented silicon steel sheet and the 3% non-oriented silicon steel sheet are 60.0 mm, 45.0 mm, and 0.5 mm, respectively.
[0037] S1.3 Surface Treatment The surfaces of the selected 1% and 3% non-oriented silicon steel sheets were polished to remove oxides, oil stains and other impurities. Then they were rinsed with alcohol. After cleaning, the 1% and 3% non-oriented silicon steel sheets were placed in acetone and ultrasonically cleaned for 2 minutes. Then they were rinsed with alcohol and dried at room temperature.
[0038] In this embodiment, it is preferable to use a wire brush to polish the surfaces of 1% non-oriented silicon steel sheets and 3% non-oriented silicon steel sheets to remove impurities such as oxides and oil stains.
[0039] S1.4 Stacking Surface-treated 1% non-oriented silicon steel sheets and 3% non-oriented silicon steel sheets are alternately stacked to form a layered stack, with the outermost layer being 3% non-oriented silicon steel sheet.
[0040] S2: Vacuum sealing of the layered stack; The specific implementation method for this step is as follows: S2.1 package The layered stack is placed in a 304 stainless steel square tube with a boron nitride coating on the inner wall, and 304 stainless steel square plugs are inserted into both ends of the square tube. In this embodiment, the preferred inner diameter of the square tube is 100.0×45.0×11.0mm, the wall thickness is 2mm, and the size of the block is 20.0×45.0×11.0mm. The square tube is used to constrain the position of the layered stack formed by the stacked 1% non-oriented silicon steel sheet and the 3% non-oriented silicon steel sheet, thereby avoiding the problem of misalignment between the 1% non-oriented silicon steel sheet and the 3% non-oriented silicon steel sheet during the hot rolling composite in the subsequent step S3. In addition, the boron nitride coating is applied to the wall of the square tube to facilitate the separation of the square tube and the layered stack in the subsequent step S3.
[0041] S2.2 Vacuum treatment Argon gas was used as a protective gas. Argon arc welding was used to seal the square block and square tube, leaving a small hole with a diameter of 1 mm. A vacuum pump was used to vacuum the square tube through the small hole to achieve a vacuum degree of 1 Pa. Then, argon gas was introduced into the square tube through the reserved small hole. Finally, the small hole was sealed to form a sample.
[0042] S3: The vacuum-treated layered stacked sample is hot-rolled and composited at a temperature of 800℃ and a total reduction rate of 80% to obtain a hot-rolled composite plate. S3.1 Hot-rolled composite: Heated at 800℃ for 1 hour, rolled in 2 passes with a total reduction of 80%, and then allowed to cool naturally in air.
[0043] S3.2 Removal of the outer shell: The square tubes and blocks used to encapsulate the layered stacked body sample are removed by mechanical processing to obtain a hot-rolled layered composite plate with 1% non-oriented silicon steel and 3% non-oriented silicon steel, and the thickness of the hot-rolled layered composite plate is 2.0~2.1mm.
[0044] S4: The hot-rolled layered composite plate is cold-rolled with a cold rolling reduction rate of 70% to obtain a cold-rolled layered composite plate with a thickness of 0.60~0.70mm.
[0045] S5: The cold-rolled layered composite plate is subjected to recrystallization annealing at a temperature of 650℃ for 60 minutes, and then cooled in air to obtain an annealed layered composite plate, namely a silicon steel layered composite plate with a magnetic induction greater than 1.70T and a yield strength greater than 360MPa.
[0046] The performance of the silicon steel layered composite plate was tested, and the results are as follows: Thickness: 0.60~0.70mm; Magnetic induction: 1.704~1.71T; Yield strength: 367~400MPa.
[0047] Figure 2 The microstructure of the finished hot-rolled layered composite plate obtained after hot rolling in step S3 above is shown.
[0048] Figure 3 The macroscopic texture diagram of the finished hot-rolled layered composite plate obtained after hot rolling in step S3 above is shown: (a) is a high silicon layer, i.e., a 3% non-oriented silicon steel layer; (b) is a low silicon layer, i.e., a 1% non-oriented silicon steel layer.
[0049] Figure 4 The microstructure of the finished cold-rolled layered composite plate obtained after cold rolling in step S4 above is shown.
[0050] Figure 5 The macroscopic texture diagram of the finished cold-rolled layered composite plate obtained after cold rolling in step S4 above is shown: (a) is the high-silicon layer; (b) is the low-silicon layer.
[0051] Figure 6 The microstructure of the finished annealed layered composite plate obtained after recrystallization annealing in step S5 above is shown.
[0052] Figure 7 The macroscopic texture diagram of the finished annealed layered composite plate obtained after recrystallization annealing in step S5 above is shown: (a) is the high silicon layer; (b) is the low silicon layer.
[0053] Observing the microscopic tissue diagrams and macroscopic texture diagrams above, it can be seen that the silicon steel layered composite plate prepared by the method of the example has good interlayer bonding and forms a favorable texture after annealing.
[0054] Comparative Example 1: Comparison of different cold rolling reduction rates 1) Sample preparation: The composite plate was prepared according to steps S1 to S5 of the embodiment, except that the cold rolling reduction rate in step S4 was 30%, 50%, and 70% respectively (labeled as CR30%, CR50%, and CR70%).
[0055] 2) Texture Analysis: The texture of composite plate samples obtained by different cold rolling reduction rates was analyzed, and the results are as follows: Figure 8 Microscopic tissue images and Figure 9 The macroscopic texture diagram is shown (summary ODF diagram of cold-rolled steel): Figure 8 In the diagram, (a) shows the microstructure of the sample with a cold rolling reduction of 30%, (b) shows the microstructure of the sample with a cold rolling reduction of 50%, and (c) shows the microstructure of the sample with a cold rolling reduction of 70%. Figure 9 In the middle: (a) is CR30%-H, that is, a high silicon layer with a cold rolling reduction rate of 30%; (b) is CR50%-H, that is, a high silicon layer with a cold rolling reduction rate of 50%; (c) is CR70%-H, that is, a high silicon layer with a cold rolling reduction rate of 70%; (d) is CR30%-L, that is, a low silicon layer with a cold rolling reduction rate of 30%; (e) is CR50%-L, that is, a low silicon layer with a cold rolling reduction rate of 50%; (f) is CR70%-L, that is, a low silicon layer with a cold rolling reduction rate of 70%.
[0056] As can be seen from the figure, in the high-silicon layer (H), the texture evolution exhibits a significant compression rate dependence: CR30%-H with {111} <112> Orientation is dominant, with an orientation density of 38.1, which is a direct result of the preferential activation of the main slip system in the early stage of cold rolling; as the reduction rate increases to 70%, the dominant position is completely lost. (CR50%-H {111}) <110> Orientation becomes dominant, and {223} appears simultaneously. <110> Orientation peaks indicate that the secondary slip system is beginning to activate, resulting in a richer texture type; {001} in CR70%-H <100> Orientation replaces the {111} series as the dominant type, with an orientation density of 32.1, becoming the core texture of CR70%-H, and is consistent with {001} in Figure (c). <100> / {001} <110> The strong peaks in the orientation correspond perfectly. This quantitative change reveals that during the high-silicon layer's cold rolling at high reduction rates, the texture undergoes a crucial transformation from a "non-magnetizable orientation" to a "magnetizable orientation," providing an important initial texture foundation for the improvement of magnetic properties during subsequent annealing. The low-silicon layer (L) exhibits stronger texture stability: {111} <112> Fiber texture remains dominant, accompanied by {001} <110> and {223} <110> With the enhancement of secondary orientations, the texture distribution becomes more uniform. It is evident that when the cold rolling reduction rate is below 50%, the deformation energy storage is insufficient, and the magnetic properties after annealing cannot reach above 1.70T; the best comprehensive performance can be obtained when the cold rolling reduction rate is 70%, with both magnetic induction and strength reaching the target values; when the cold rolling reduction rate is above 75%, microcracks appear in the composite plate, and the forming quality decreases.
[0057] Comparative Example 2: Comparison of different hot-rolling parameters 1) Sample preparation: The composite plate was prepared according to steps S1 to S5 of the embodiment, except that the following hot rolling parameters were used to prepare the sample during the hot rolling process in step S3: HR950℃-90%: Hot rolling temperature 950℃, total reduction rate 90%, other steps are the same as in the example; HR800℃-80%: Same as the example (hot rolling temperature 800℃, total reduction rate 80%).
[0058] 2) Organization and texture analysis: such as Figure 10 The microstructure of the composite plate under two hot-rolling parameters is shown. Figure 11 It demonstrates its textural features.
[0059] Figure 10 In the image: (a) is a microstructure of a sample hot-rolled at 950℃ with a total reduction of 90%; (b) is a microstructure of a sample hot-rolled at 800℃ with a total reduction of 80%. Figure 11In the diagram, (a) represents HR950℃-90%-H, which means a high silicon layer with a hot rolling temperature of 950℃ and a total reduction rate of 90%; (b) represents HR950℃-90%-L, which means a low silicon layer with a hot rolling temperature of 950℃ and a total reduction rate of 90%; (c) represents HR800℃-80%-H, which means a high silicon layer with a hot rolling temperature of 800℃ and a total reduction rate of 80%; and (d) represents HR800℃-80%-L, which means a low silicon layer with a hot rolling temperature of 800℃ and a total reduction rate of 80%.
[0060] As can be seen from the figure: At a hot rolling temperature of 950℃ and a total reduction rate of 90%, the grains undergo a dynamic recrystallization process at high temperatures, resulting in grain refinement and a more uniform distribution of textures in different layers. Furthermore, the high temperature promotes the diffusion of silicon, causing the composition and crystal structure of the high-silicon layer and the low-silicon layer to gradually become more consistent.
[0061] At a hot rolling temperature of 800℃ and a total reduction rate of 80%, the texture strength of the high-silicon layer is at {223}. <110> The texture strength of the low-silicon layer is at {111} <120> The two are clearly distinguishable, maintaining the pre-set differences between layers.
[0062] When the hot rolling temperature is too low (<780℃), a strong metallurgical bond cannot be achieved between the layers; when the hot rolling temperature is too high (>850℃) and the reduction rate is too large, the element diffusion is excessive, the composition between the layers tends to be uniform, which destroys the layered structure of "high silicon surface layer and low silicon core layer" and leads to a decrease in magnetic properties; hot rolling at 800℃ and a reduction rate of 80% can effectively control the degree of element diffusion while ensuring sufficient metallurgical bond between the layers, laying a good foundation for subsequent cold rolling and annealing.
[0063] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.
Claims
1. A method for preparing a silicon steel layered composite plate with excellent magnetic properties, characterized in that, Includes the following steps: S1: Alternately stack 1%Si non-oriented silicon steel sheets and 3%Si non-oriented silicon steel sheets, with the 3%Si non-oriented silicon steel sheet on the outermost side, to form a layered stack; S2: Vacuum sealing process is performed on the layered stack; S3: The layered stacked body after vacuum sealing is hot rolled together at a temperature of 780℃~850℃ and a total reduction rate of 75%~85% to obtain a hot rolled composite plate. S4: The hot-rolled composite plate is cold-rolled with a cold rolling reduction rate of 50%~75% to obtain a cold-rolled composite plate; S5: The cold-rolled composite plate is subjected to recrystallization annealing at a temperature of 600℃~700℃ and a holding time of 60 minutes to obtain a silicon steel layered composite plate with a magnetic induction greater than 1.70T and a yield strength greater than 360MPa.
2. The method for preparing the silicon steel layered composite plate with excellent magnetic properties according to claim 1, characterized in that, In the layered stack, the 1%Si non-oriented silicon steel sheet and the 3%Si non-oriented silicon steel sheet have the same length, width and thickness. The total number of layers in the layered stack formed by the alternating stacking of the two is an odd number of layers, and the number of layers of the 3% non-oriented silicon steel layer is one more than the number of layers of the 1% non-oriented silicon steel layer.
3. The method for preparing the silicon steel layered composite plate with excellent magnetic properties according to claim 1, characterized in that, In step S2, the vacuum sealing process specifically involves placing the layered stacked body into a 304 stainless steel square tube with a boron nitride coating on the inner wall, inserting 304 stainless steel plugs into both ends of the square tube, welding and sealing it, then evacuating to 1 Pa and filling it with argon gas for protection.
4. The method for preparing the silicon steel layered composite plate with excellent magnetic properties according to claim 1, characterized in that, The specific process of hot-rolled composite is as follows: heating at 800℃ for 1 hour, performing two rolling passes, with a total reduction rate of 80%, to obtain a hot-rolled composite plate with a thickness of 2.0~2.1mm.
5. The method for preparing the silicon steel layered composite plate with excellent magnetic properties according to claim 1, characterized in that, In step S4, the thickness of the cold-rolled composite plate is 0.60~0.70mm.
6. The method for preparing the silicon steel layered composite plate with excellent magnetic properties according to claim 1, characterized in that, The hot rolling temperature is 800℃, the total hot rolling reduction rate is 80%, the cold rolling reduction rate is 70%, and the annealing temperature is 650℃.
7. A silicon steel layered composite plate with excellent magnetic properties, prepared by the preparation method according to any one of claims 1-6, characterized in that, The thickness of the silicon steel layered composite plate is 0.70 mm or less, the magnetic induction is 1.704~1.71T, and the yield strength is 367~400MPa.