A kind of high magnetic induction non-oriented high-silicon steel ultra-thin strip, its preparation method and application

Abstract

The present invention relates to a high magnetic induction non-oriented high-silicon steel ultra-thin strip, a preparation method and an application thereof, belonging to the technical field of non-oriented silicon steel, and solving at least one of the following problems existing in the preparation method and products of existing non-oriented high-silicon steel thin strips: it is difficult to achieve high magnetic induction and low iron loss while maintaining isotropic magnetic properties; it is difficult to make the material very thin while obtaining isotropic high magnetic induction and excellent comprehensive magnetic properties; the process route is complex, the environmental pollution is serious, and the cost is relatively high. A preparation method of a high magnetic induction non-oriented high-silicon steel ultra-thin strip includes: S1. Warm rolling: Warm-rolling a cast thin plate of high-silicon steel into a warm-rolled plate, annealing, oil quenching and pickling to obtain an annealed warm-rolled plate; S2. Cold rolling: Cold-rolling the annealed warm-rolled plate into a cold-rolled plate with a thickness ≤ 0.1 mm and annealing. The process route of the present invention is relatively simple, the cost is low, and it is environmentally friendly, and it can produce a non-oriented high-silicon steel ultra-thin strip with ultra-thin thickness, isotropic high magnetic induction and excellent comprehensive magnetic properties.

Description

Technical Field

[0001] The present invention relates to the technical field of non-oriented silicon steel, and particularly to a non-oriented high-silicon steel ultra-thin strip with high magnetic induction, a preparation method thereof, and an application thereof. Background Art

[0002] Non-oriented high-silicon steel thin strips have broad application prospects in high-end motors used at medium and high frequencies. Along with the requirements for miniaturization, lightweight design, and high efficiency of iron cores, it is necessary to improve the magnetic properties of high-silicon steel thin strips and further reduce their thickness.

[0003] The existing preparation methods of high-silicon steel thin strips mainly include: traditional rolling method, non-traditional rolling methods (such as chemical vapor deposition method, spray forming method, powder rolling method). However, these preparation methods and the obtained high-silicon steel thin strips have the following problems: According to existing research, in most cases, it is difficult to meet the following magnetic property requirements: that is, while ensuring a small degree of anisotropy, obtaining high magnetic induction (such as B 50 reaching above 1.6) and low iron loss (such as P 1.0 / 400 less than 15 W / kg). High-silicon steel thin strips are prone to anisotropy during the preparation process, that is, the magnetic properties are different in different directions. Controlling this difference within a small range and simultaneously meeting the requirements of high magnetic induction and low iron loss is a technical challenge. It is difficult for the traditional rolling method to prepare high-silicon steel ultra-thin strips that meet the above magnetic property requirements; only a small part of the non-traditional rolling methods can approach the above magnetic property requirements, but there are problems such as complex process routes (such as powder rolling method), thickness limitation (such as spray forming method), environmental pollution, and high cost (such as chemical vapor deposition method).

[0004] In summary, for non-oriented high-silicon steel ultra-thin strips, it is necessary to develop a relatively simple, low-cost, environmentally friendly processing technology that can obtain high magnetic induction and excellent comprehensive magnetic properties. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide a non-oriented high-silicon steel ultra-thin strip with high magnetic induction, a preparation method thereof, and an application thereof, so as to solve at least one of the following problems existing in the existing preparation methods of non-oriented high-silicon steel thin strips and their products: (1) It is difficult to achieve high magnetic induction (B 50 > 1.6 T) and low iron loss (P 1.0 / 400 < 15 W / kg) while maintaining isotropic magnetic properties; (2) It is difficult to achieve a very thin material (for example: thickness ≤ 0.1 mm) while obtaining isotropic high magnetic induction and excellent comprehensive magnetic properties; (3) Complex process route, environmental pollution, and high cost.

[0006] The object of the present invention is achieved by the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing an ultra-thin strip of high-magnetic-induction non-oriented high-silicon steel, comprising the following steps:

[0008] S1. Warm rolling: Preheat a high-silicon steel casting thin plate with a thickness H 0 of 1 - 3 mm to a temperature T 1 = 780 - 850 °C, and warm roll it into a warm-rolled plate with a thickness H 1 of 0.5 - 0.7 mm. The temperature range of warm rolling is set to 600 - 750 °C;

[0009] Anneal the warm-rolled plate. The annealing temperature T 2 = 800 - 900 °C, and the annealing time t 2 = 15 - 25 min. After annealing, perform oil quenching and pickling to obtain an annealed warm-rolled plate;

[0010] S2. Cold rolling: Preheat the annealed warm-rolled plate to a temperature T 3 = 290 - 310 °C, and cold roll it into a cold-rolled plate with a thickness H 2 ≤ 0.1 mm. The temperature range of cold rolling is set to room temperature - 250 °C;

[0011] Anneal the cold-rolled plate. The annealing temperature T 4 = 800 - 900 °C, and the annealing time t 4 = 45 - 90 min to obtain an ultra-thin strip of high-magnetic-induction non-oriented high-silicon steel.

[0012] Furthermore, in step S1, the total reduction ratio R a of the warm rolling is 50 - 70%, the number of rolling passes M is 2 - 4 passes, and the reduction ratio R a1 to R aM of each pass is controlled within 20% - 35%.

[0013] Furthermore, in step S2, the total reduction ratio R b of the cold rolling is 80 - 92%, the number of rolling passes N is 3 - 5 passes, and the reduction ratio R b1 to R bN of each pass is controlled within 15 - 40%.

[0014] Furthermore, in step S2, the reduction ratio R b1 of the first pass of cold rolling is controlled within 35 - 40%, and the reduction ratio R b2 to R bN of the subsequent passes is controlled within 15 - 38%.

[0015] Furthermore, in step S1, the annealing time t 2 = 18 - 22 min; and / or, in step S2, the annealing time t 4 = 50 - 70 min.

[0016] Further, T 2 =T 4 =820~880℃;and / or, T 1 =780~820℃;and / or, T 3 =295~305℃.

[0017] Further, in step S2, before annealing, the annealing furnace is heated to T 4 , and then put in the cold rolled sheet.

[0018] Further, in step S1, the preheating to temperature T 1 After insulation, insulation time t 1 = 20 to 40 min; and / or, in step S2, the preheating to temperature T 3 After insulation, insulation time t 3 =5~10min.

[0019] In a second aspect, the present invention further provides a high magnetic induction non-oriented high silicon steel ultra-thin strip obtained by the preparation method described in the first aspect, wherein the thickness of the high magnetic induction non-oriented high silicon steel ultra-thin strip is ≤0.1 mm, and the magnetic induction B 50 ≥1.62T, iron loss P 1.0 / 400 <15W / kg, vertical and horizontal difference of magnetic induction S 1 The absolute value of the iron loss is less than 2.0%, and the longitudinal and transverse difference of iron loss is S 2 The absolute value is less than 2.0%.

[0020] The present invention also provides the use of the high magnetic induction non-oriented high silicon steel ultra-thin strip obtained by the preparation method as described in the first aspect or the high magnetic induction non-oriented high silicon steel ultra-thin strip as described in the second aspect in a motor.

[0021] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0022] (1) The preparation method provided by the present invention eliminates the hot rolling process, has a simple process route, low cost, and is environmentally friendly, and can produce ultra-thin, isotropic, high magnetic induction, and excellent comprehensive magnetic properties of non-oriented high silicon steel ultra-thin strips; through the tacit cooperation of warm rolling and cold rolling, the plasticization is gradually enhanced to improve the processing performance, and a high magnetic induction non-oriented high silicon steel ultra-thin strip with a thickness of ≤0.1mm is successfully produced; through the reasonable ratio of warm rolling and cold rolling reduction rates, combined with the design of rolling process and annealing system, under the condition of ensuring good processing performance, the unfavorable γ line (plate normal ND / / <111> ) texture formation, obtaining uniform and appropriately sized grain structure, and reducing magnetic anisotropy, so that the obtained high silicon steel ultra-thin strip can exhibit high magnetic induction and low iron loss in all directions, that is, to achieve high magnetic induction B while ensuring that the absolute value of the difference between the iron loss and the longitudinal and transverse directions of the magnetic induction is less than 2%.50 ≥1.62T, low iron loss P 1.0 / 400 <15 W / kg. Specifically, through warm rolling reduction ratio (rolling from 1 - 3 mm to 0.5 - 0.7 mm) to ensure a relatively high cold rolling reduction ratio can be achieved subsequently, and through a large cold rolling reduction ratio (rolling from 0.5 - 0.7 mm to 0.1 mm and below), the adverse γ - fiber texture after cold rolling annealing can be effectively suppressed; through a carefully designed warm rolling process and warm rolling annealing system, such as controlling the pre - heating temperature T 1 before warm rolling, the warm rolling temperature range, the annealing temperature T 2 after warm rolling, and the annealing time t 2 as well as rapid oil quenching and rapid cooling after annealing, while ensuring workability, the adverse γ - fiber texture can be suppressed, and a uniform and moderately grown grain structure can be obtained, providing a good foundation for achieving high magnetic induction, low iron loss, and isotropy of the final product; through a carefully designed cold rolling process and cold rolling annealing system, such as controlling the pre - heating temperature T 3 before cold rolling and the cold rolling temperature range, as well as the annealing temperature T 4 after cold rolling and the annealing time t 4 , the adverse γ - fiber texture can be suppressed, and a uniform and appropriately sized grain structure can be obtained, thereby improving magnetic induction and reducing iron loss while ensuring a very small degree of anisotropy.

[0023] (2) In some preferred embodiments, during warm rolling, by selecting an appropriate total reduction ratio, number of rolling passes, and controlling the reduction ratio of each pass within a suitable range, while ensuring the workability of the material, the isotropy of the material can be further improved and the formation of adverse γ - fiber texture can be reduced, which is also beneficial for obtaining a coarser and more uniform and moderately grown grain, thus providing a better foundation for improving the anisotropic magnetic properties of the final product.

[0024] (3) In some preferred embodiments, during cold rolling, by selecting an appropriate total reduction ratio, number of rolling passes, and controlling the reduction ratio of each pass within a suitable range, while ensuring the workability of the material, the isotropy of the material can be further improved and the formation of adverse γ - fiber texture can be reduced, which is also beneficial for obtaining a more uniform and appropriately sized grain, thereby further improving the anisotropic magnetic properties of the final product.

[0025] (4) In some preferred embodiments, after warm rolling and cold rolling, by selecting a more appropriate annealing temperature and annealing time (e.g., T 2 = T 4 = 820 - 880 °C, t 2 = 18 - 22 min, t 4= 50 - 70 min), which is beneficial to further reduce the formation of unfavorable γ - fiber texture and obtain a more uniform and appropriately sized grain structure, thereby further improving the magnetic properties of the final product and reducing the anisotropy of magnetic properties. Before warm rolling and cold rolling, by selecting a more appropriate preheating temperature (such as T 1 = 780 - 820 °C; T 3 = 295 - 305 °C) and controlling the holding time after reaching the preheating temperature (such as t 1 = 20 - 40 min, t 3 = 5 - 10 min), it is beneficial to improve the processability, reduce the number of rolling passes, improve the processing efficiency, and further improve the magnetic anisotropy of the product while ensuring the product quality.

[0026] (5) In some preferred embodiments, before annealing after cold rolling, first heat the annealing furnace to a preset temperature T 4 , and then put in the cold - rolled sheet, which can reduce the release of stored energy during the heating process of the cold - rolled sheet, is beneficial to suppressing the γ - fiber recrystallization texture, and helps to further improve the overall magnetic properties.

[0027] (6) The preparation method of the present invention can obtain ultra - thin non - oriented high - silicon steel sheets with a thickness ≤ 0.1 mm, which have excellent performance in magnetic properties, such as high magnetic induction, low iron loss, and low anisotropy degree, and have broad application prospects, especially in the field of manufacturing motor cores that require lightweight, miniaturization, and high efficiency.

[0028] In the present invention, the above - mentioned technical solutions can also be combined with each other to achieve more preferred combination schemes. Other features and advantages of the present invention will be described in the following description, and some advantages can be made obvious from the description, or understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained from the content specifically pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings are only for the purpose of showing specific embodiments and are not considered as limiting the present invention. Throughout the drawings, the same reference numerals represent the same components.

[0030] Figure 1 is the microstructure and texture diagram of the non - oriented high - silicon steel ultra - thin strip prepared in Example 1 of the present invention, where (a) is the microstructure diagram and (b) is the texture diagram;

[0031] Figure 2 is the microstructure and texture diagram of the non - oriented high - silicon steel ultra - thin strip prepared in Example 2 of the present invention, where (a) is the microstructure diagram and (b) is the texture diagram;

[0032] Figure 3Microstructure and texture diagrams of the high-silicon steel thin strip prepared in Comparative Example 3, where (a) is the microstructure diagram and (b) is the texture diagram;

[0033] Figure 4 Microstructure and texture diagrams of the high-silicon steel thin strip prepared in Comparative Example 6, where (a) is the microstructure diagram and (b) is the texture diagram. Specific Embodiments

[0034] The following will specifically describe the preferred embodiments of the present invention with reference to the accompanying drawings. The accompanying drawings form a part of this application and are used together with the embodiments of the present invention to explain the principles of the present invention, rather than to limit the scope of the present invention.

[0035] To solve the problem of the brittleness of high-silicon steel, the gradually plasticizing technology developed in recent years, that is, the three-step rolling method of "hot rolling - warm rolling - cold rolling" plus a reasonable heat treatment process, can be used to prepare thin-gauge high-silicon steel thin strips. Compared with chemical vapor deposition, spray forming, and powder rolling methods, this technology has the advantages of energy conservation, environmental protection, simpler process, and lower cost. However, the current gradually plasticizing technology has the following technical bottlenecks: it is difficult to achieve high magnetic induction (B 50 > 1.6 T) and low iron loss (P 1.0 / 400 < 15 W / kg) in ultra-thin high-silicon steel materials while maintaining isotropic magnetic properties. The "ultra-thin" in the present invention refers to a thickness specification ≤ 0.1 mm. The applicant found in the research that the main reason for the above bottleneck is that the process design of the existing gradually plasticizing technology is unreasonable, making it difficult to obtain a uniform microstructure and optimized texture while reducing the thickness, resulting in the inability to obtain isotropic high magnetic induction and high-silicon steel ultra-thin strips with excellent comprehensive magnetic properties.

[0036] Based on this, on the one hand, the present invention provides a method for preparing an ultra-thin strip of high-magnetic-induction non-oriented high-silicon steel, comprising the following steps:

[0037] S1. Warm rolling: Preheat a high-silicon steel cast thin plate with a thickness H 0 of 1 - 3 mm to a temperature T 1 = 780 - 850 °C, and warm roll it into a warm-rolled plate with a thickness H 1 of 0.5 - 0.7 mm. The temperature range of warm rolling is set to 600 - 750 °C;

[0038] Anneal the warm-rolled plate, with the annealing temperature T 2 = 800 - 900 °C and the annealing time t 2 = 15 - 25 min. After annealing, oil quench and pickling to obtain an annealed warm-rolled plate;

[0039] S2. Cold rolling: Preheat the annealed warm-rolled plate to a temperature T 3 = 290 - 310 °C, and cold roll it into a thickness H2 For cold-rolled sheets with a thickness of ≤0.1 mm, the cold-rolling temperature range is set at room temperature to 250°C;

[0040] The cold rolled sheet is annealed at a temperature T 4 =800~900℃, annealing time t 4 = 45 ~ 90min, to obtain a high magnetic induction non-oriented high silicon steel ultra-thin strip.

[0041] Compared with the prior art, the preparation method provided by the present invention omits the hot rolling process, has a simple process route, low cost and is environmentally friendly; through the tacit cooperation of warm rolling and cold rolling, the plasticization is gradually enhanced to improve the processing performance, and a high magnetic induction non-oriented high silicon steel ultra-thin strip with a thickness of ≤0.1mm is successfully prepared; through the reasonable ratio of warm rolling and cold rolling reduction rates, combined with the design of rolling process and annealing system, the unfavorable γ line (plate normal ND / / ) is effectively suppressed while ensuring good processing performance. <111> ) texture formation, obtaining uniform and appropriately sized grain structure, and reducing magnetic anisotropy, so that the obtained high silicon steel ultra-thin strip can exhibit high magnetic induction and low iron loss in all directions, that is, to achieve high magnetic induction B while ensuring that the absolute value of the difference between the iron loss and the longitudinal and transverse directions of the magnetic induction is less than 2%. 50 ≥1.62T, low iron loss P 1.0 / 400 <15W / kg. Specifically, the warm rolling reduction rate (from 1 to 3 mm to 0.5 to 0.7 mm) is used to ensure that a higher cold rolling reduction rate can be achieved in the subsequent process, and a larger cold rolling reduction rate (from 0.5 to 0.7 mm to 0.1 mm and below) is used to effectively suppress the unfavorable γ-line texture after cold rolling annealing; through the carefully designed warm rolling process and post-warm rolling annealing system, such as controlling the preheating temperature T before warm rolling 1 , warm rolling temperature range, annealing temperature after warm rolling T 2 , annealing time t 2 And oil quenching and rapid cooling after annealing can suppress the unfavorable γ-line texture and obtain uniform and moderately grown grain structure, which provides a good foundation for achieving high magnetic induction, low iron loss and isotropy of the final product; through carefully designed cold rolling process and post-cold rolling annealing system, such as controlling the preheating temperature T before cold rolling 3 and cold rolling temperature range, and annealing temperature after cold rolling T 4 , annealing time t 4 , which can suppress the unfavorable γ-ray texture and obtain a uniform and appropriately sized grain structure, thereby improving the magnetic induction and reducing the iron loss while ensuring a small degree of anisotropy.

[0042] Specifically, in step S1, the initial thickness H of the high silicon steel casting sheet is 0 The thickness range is 1 to 3 mm. This thickness range is suitable for direct warm rolling without the need for hot rolling to reduce the thickness, thereby further simplifying the processing steps and reducing energy consumption.

[0043] Specifically, in step S1, the high-silicon steel cast thin sheet is first preheated to temperature T 1 = 780 - 850 °C. Before warm rolling, preheating the thin sheet to a suitable temperature (30 - 100 °C higher than the upper limit of the warm rolling temperature range) can make the warm rolling process easier to carry out, improve the processing performance, reduce defects, make the material deform more uniformly during warm rolling, help obtain a more uniform microstructure, improve the magnetic property isotropy, be conducive to controlling the deformation mechanism of the material, thereby suppressing the formation of unfavorable γ-fiber texture, and can promote a certain degree of recovery of the material during warm rolling, providing a good foundation for forming a uniform grain structure subsequently, and thus improving the anisotropic magnetic properties of the material. Preferably, T 1 = 780 - 820 °C; Exemplarily, T 1 = 790 °C, 800 °C, 810 °C.

[0044] Specifically, in step S1, by controlling the total reduction ratio of warm rolling (rolling from 1 - 3 mm to 0.5 - 0.7 mm, that is, the total reduction ratio R a is 30% - 83%), it is beneficial to ensure a higher reduction ratio can be achieved during the subsequent cold rolling process, which not only helps reduce the magnetic property anisotropy, thereby providing similar magnetic properties in all directions, but also can suppress the formation of unfavorable γ-fiber texture and obtain a more uniform grain structure, all of which contribute to improving the comprehensive magnetic properties of the material.

[0045] Specifically, in step S1, by controlling the warm rolling temperature range and setting it to 600 - 750 °C, the formation of unfavorable γ-fiber texture can be suppressed, and obtaining a more uniform and moderately grown grain structure can be promoted. The specific principle is: since γ-fiber grain nucleation mostly occurs at grain boundaries or inside the γ-fiber deformed structure, within the above-mentioned suitable warm rolling temperature range, it helps to form a uniform and moderately grown grain structure. The moderately grown grain structure can reduce the number of grain boundaries, make the deformed structure more uniform, reduce the nucleation and preferred growth of γ-fiber grains inside the deformed structure, thereby ensuring that there is no significant γ-fiber texture in the texture of the warm rolled sheet, providing a good foundation for suppressing the γ-fiber texture in the subsequent cold rolled annealed sheet. Exemplarily, the warm rolling temperature range can be set to 625 - 750 °C, 650 - 750 °C, 675 - 750 °C, 700 - 750 °C, 725 - 750 °C.

[0046] Specifically, in step S1, by controlling the annealing regime after warm rolling, that is, setting the annealing temperature T 2 = 800 - 900 °C and the annealing time t 2 = 15 - 25 min, it can promote the obtaining of a relatively coarse grain structure, provide better processing performance for the subsequent cold rolling and a better foundation for the subsequent texture control of the structure. The specific principle is: using the above-mentioned T 2 and t with a synergistic effect2 so that the annealed warm-rolled sheet obtains a uniform and appropriately sized grain structure, suppressing the nucleation of fine γ-line grains at grain boundaries and within grains during subsequent cold rolling and annealing processes, which is beneficial for forming a grain structure with optimized texture, uniform and moderately grown grains. For magnetic materials, a uniform and moderately grown grain structure helps reduce the pinning of magnetic domain walls, improve magnetic induction, reduce iron loss, and does not cause differences in magnetic properties in different directions of silicon steel sheets. Preferably, T 2 = 820 - 880 °C, t 2 = 18 - 22 min. Exemplarily, T 2 = 830 °C, 840 °C, 850 °C, 860 °C, 870 °C, t 2 = 19 min, 20 min, 21 min.

[0047] Specifically, in step S1, after annealing, rapid cooling by oil quenching can effectively suppress the formation of partial ordered phase B2 and inhibit the transformation of B2 phase to DO 3 phase, thereby improving the subsequent cold rolling plasticity and providing better processing performance for subsequent cold rolling. Preferably, the quenching oil used for oil quenching includes at least one of rapid bright quenching oil and environmentally friendly water-soluble quenching liquid.

[0048] It can be understood that the annealed warm-rolled sheet obtained in step S1 is pickled to remove surface oxides and make the surface clean.

[0049] Specifically, in step S2, the pickled annealed warm-rolled sheet is preheated to T 3 = 290 - 310 °C. By preheating the annealed warm-rolled sheet to a suitable temperature (40 - 60 °C higher than the upper limit of the cold rolling temperature range) before cold rolling, it helps improve processing performance, improve the uniformity of the microstructure, and reduce the formation of unfavorable γ-line texture. The specific principle is as follows: an appropriate preheating temperature can reduce the deformation resistance of the material, making the cold rolling process easier to carry out, increase the plasticity of the material, reduce the risk of cracks and fractures during cold rolling, and improve processing performance; an appropriate preheating temperature helps promote thermal equilibrium within the material and reduce microstructure non-uniformity caused by temperature non-uniformity; an appropriate preheating temperature helps break the deformed microstructure that may promote the formation of γ-line texture, thereby reducing the formation of unfavorable texture. Preferably, T 3 = 295 - 305 °C; Exemplarily, T 3 = 298 °C, 300 °C, 302 °C.

[0050] Specifically, in step S2, by controlling the total reduction ratio of cold rolling (rolling from 0.5 - 0.7 mm to 0.1 mm and below, i.e., the total reduction ratio R b≥80%), that is, adopting a larger cold rolling reduction ratio helps to promote the formation of specific textures, such as the α*({h,1,1}<1 / h,1,2>) texture. Due to the competitive relationship between textures, promoting the formation of one texture will naturally inhibit the development of another texture, thereby suppressing the formation of the unfavorable γ-fiber texture. The texture characteristics at this time also help to reduce the magnetic anisotropy of the material, and while reducing the iron loss, the magnetic induction in all directions is uniformly improved.

[0051] Specifically, in step S2, by controlling the temperature range of cold rolling to be set as room temperature to 250 °C, while improving the processing performance, it is beneficial to inhibit the formation of the unfavorable γ-fiber texture and promote the obtaining of a more uniform grain structure. The specific principle is as follows: Warm rolling with temperature reduces the deformation resistance and work hardening of the material, enabling the thinner warm-rolled sheet to withstand greater deformation without fracture, and can reach the required thickness reduction in fewer passes, improving production efficiency; because after the warm rolling annealing process in step S1, it is a relatively coarse grain that is uniform and moderately grown, adopting the above cold rolling temperature range can promote the formation of a shear band with a suitable ratio during the rolling process of silicon steel. The shear band can undergo dominant shear band η-line nucleation during subsequent annealing, thereby forming a η-line (<001> / / RD) texture with a suitable ratio. Here, the suitable ratio can improve the magnetic properties (i.e., high magnetic induction and low iron loss) while ensuring a small degree of magnetic anisotropy. Exemplarily, the cold rolling temperature range can be set as 50 - 250 °C, 100 - 250 °C, 150 - 250 °C, 200 - 250 °C.

[0052] Specifically, in step S2, by controlling the annealing system after cold rolling, that is, setting the annealing temperature T 4 = 800 - 900 °C and the annealing time t 4 = 45 - 90 min, it can inhibit the formation of the unfavorable γ-fiber texture after annealing, and help to obtain a more uniform and appropriately sized grain structure, improve the magnetic properties in all directions, and enhance the plasticity of the final product. The specific principle is as follows: Adopting the above synergistic T 4 and t 4 , helps to reduce the nucleation inside the γ-fiber deformed grains caused by cold rolling, helps to reduce the nucleation advantage at the grain boundaries, thereby reducing the formation of the γ-fiber texture; by adopting a suitable T 4 and t 4, it is possible to adjust the grain growth rate, allow grains to nucleate uniformly inside the material, reduce the preferential growth of specific grain orientations, thereby forming a uniform and appropriately sized grain structure, and suppressing the γ - fiber texture and obtaining a uniform and appropriately sized grain structure contribute to improving the magnetic properties of the material and reducing the anisotropy of magnetic properties; at the same time, an appropriate annealing regime helps to release the internal stress accumulated during the cold rolling process, reduce stress - concentrated areas, and the uniform grain structure and reduced internal stress contribute to improving the plasticity of the obtained strip, making it easier to deform during further processing and forming, reducing the risk of cracks and fractures during actual application, and improving the yield rate and reliability. Preferably, T 4 = 820 - 880 °C and the annealing time t 4 = 50 - 70 min. Exemplarily, T 4 = 830 °C, 840 °C, 850 °C, 860 °C, 870 °C, and t 4 = 55 min, 60 min, 65 min.

[0053] In some preferred embodiments, in step S1, the total reduction ratio R a of warm rolling is 50 - 70%, the number of rolling passes M is 2 - 4 passes, and the reduction ratio R a1 to R aM of each pass is controlled within 20% - 35%. During warm rolling, by selecting an appropriate total reduction ratio and number of rolling passes and controlling the reduction ratio of each pass within an appropriate range, while ensuring the workability of the material, the isotropy of the material can be further improved and the formation of unfavorable γ - fiber texture can be reduced, which is also beneficial to obtaining a more uniform and moderately grown coarser grain, thus providing a better basis for improving the anisotropic magnetic properties of the final product. Exemplarily, the total reduction ratio R a of warm rolling is 55%, 60%, 65%, and the number of warm - rolling passes is 2 passes, 3 passes, 4 passes.

[0054] In some preferred embodiments, in step S2, the total reduction ratio R b of cold rolling is 80 - 92%, the number of rolling passes N is 3 - 5 passes, and the reduction ratio R b1 to R bN of each pass is controlled within 15 - 40%. During cold rolling, by selecting an appropriate total reduction ratio and number of rolling passes and controlling the reduction ratio of each pass within an appropriate range, while ensuring the workability of the material, the isotropy of the material can be further improved and the formation of unfavorable γ - fiber texture can be reduced, which is also beneficial to obtaining a more uniform and appropriately sized grain, thereby further improving the anisotropic magnetic properties of the final product. More preferably, the total reduction ratio R b of cold rolling is 83 - 90%. Exemplarily, the total reduction ratio R bare 84%, 85%, 86%, 87%, 88%, 89%; the number of cold rolling passes N is 3 passes, 4 passes, 5 passes.

[0055] In some preferred embodiments, the reduction ratio R of the first cold rolling pass b1 is controlled at 35-40%, and the reduction ratio R of the subsequent passes b2 to R bN is controlled at 15-38%. With such settings, the following advantages are achieved: (1) Improving processing performance: A relatively high reduction ratio in the first pass can quickly reduce the thickness of the material. As cold rolling progresses in the first pass, the temperature decreases, and at the same time, the material undergoes work hardening. Reducing the reduction ratio in subsequent passes helps to adapt to the increased deformation resistance due to hardening and maintain the smooth progress of the processing; (2) Improving the overall magnetic properties: It is related to the temperature range during rolling. A larger deformation in the first pass can promote the formation of favorable textures, while a smaller reduction ratio in subsequent passes helps to inhibit the development of unfavorable γ-fiber textures, contributing to obtaining a uniform and moderately grown grain structure, thereby optimizing the overall magnetic properties, increasing the magnetic induction and reducing the iron loss, and ensuring that the magnetic property differences in all directions of the material are small. Exemplarily, the reduction ratio R of the first cold rolling pass b1 is controlled at 36%, 37%, 38%, 39%, and the reduction ratio R of the subsequent passes b2 to R bN is controlled at 18%, 20%, 25%, 30%, 35%. In a possible design, the reduction ratio R of the subsequent passes b2 to R bN decreases sequentially.

[0056] In some preferred embodiments, in step S2, before annealing, the annealing furnace is first heated to T 4 , and then the cold-rolled sheet is placed in it; since the annealing furnace has been pre-heated to T 4 , the cold-rolled sheet can quickly reach the required temperature T 4 after being placed, reducing the release of stored energy during the heating process of the cold-rolled sheet. Because once the stored energy decreases, it will enhance the unfavorable γ-fiber texture and weaken the favorable texture; therefore, quickly heating the cold-rolled sheet to the annealing temperature T 4 is beneficial to inhibiting the γ-fiber recrystallization texture, thereby contributing to improving the overall magnetic properties.

[0057] In some preferred embodiments, in step S1, after preheating to the temperature T 1 , keep it warm, and the holding time t 1 = 20-40 min; in step S2, after preheating to the temperature T 3 , keep it warm, and the holding time t 3= 5 - 10 min. Using the above appropriate holding time is beneficial to improving the processing performance of subsequent warm rolling and cold rolling, and also helps to optimize the microstructure, reduce the adverse γ - fiber texture, improve the grain uniformity, and thus helps to improve the magnetic properties of the material in all directions (increase the magnetic induction and reduce the iron loss).

[0058] In some preferred embodiments, during the warm rolling in step S1, the temperature is raised to T between passes by reheating in a furnace 1 and held for 1 - 2 min to ensure that the warm rolling temperature is within the set range, which is beneficial to the smooth progress of processing and also beneficial to the control of the microstructure and the optimization of the texture.

[0059] It should be noted that during the cold rolling in step S2, when the cold rolling temperature range is set as room temperature - 250 °C, there is no need to reheat in a furnace between passes, which improves the efficiency; in some possible designs, when the lower limit of the cold rolling temperature range is higher than room temperature, such as set as 50 - 250 °C, 100 - 250 °C, 150 - 250 °C, 200 - 250 °C, the temperature is raised to T between passes by reheating in a furnace 3 , but there is no need for holding.

[0060] Preferably, in steps S1 and S2, the "annealing" is carried out under the protection of an inert gas; more preferably, the pre - heating before warm rolling and the pre - heating before cold rolling are also carried out under the protection of an inert gas. Exemplarily, the inert gas is nitrogen.

[0061] In a second aspect, the present invention also provides a high - magnetic - induction non - oriented high - silicon steel ultra - thin strip obtained by using the preparation method as described above. The thickness H of the high - magnetic - induction non - oriented high - silicon steel ultra - thin strip 2 ≤0.1 mm, the magnetic induction B 50 ≥1.62 T, the iron loss P 1.0 / 400 <15 W / kg, the absolute value of the longitudinal - transverse difference S of the magnetic induction 1 <2.0%, and the absolute value of the longitudinal - transverse difference S of the iron loss 2 <2.0%.

[0062] Exemplarily, the thickness of the high - magnetic - induction non - oriented high - silicon steel ultra - thin strip is 0.08 mm, 0.06 mm, 0.05 mm, 0.04 mm, 0.03 mm.

[0063] In some possible designs, the chemical composition of the high - magnetic - induction non - oriented high - silicon steel ultra - thin strip by weight percentage includes: Si: 5.5% - 6.6%, C ≤ 0.02%, Mn ≤ 0.04%, N ≤ 0.004%, P ≤ 0.01%, S ≤ 0.005%, and the rest is Fe and unavoidable impurities.

[0064] The present invention also provides the application of the high magnetic induction non-oriented high silicon steel ultra-thin strip obtained by the preparation method as described in the first aspect or the high magnetic induction non-oriented high silicon steel ultra-thin strip as described in the second aspect in an electric motor; for example: the application in the iron core of an electric motor.

[0065] The technical solution of the present invention will be further described in detail below in conjunction with specific examples and comparative examples.

[0066] Example 1:

[0067] This example provides a preparation method of a high magnetic induction non-oriented high silicon steel ultra-thin strip. The chemical composition of the high magnetic induction non-oriented high silicon steel ultra-thin strip includes, by weight percentage: Si: 6.2%, C: 0.018%, Mn: 0.015%, N: 0.0038%, P: 0.006%, S: 0.004%, and the rest is Fe and unavoidable impurities. The preparation method includes the following steps:

[0068] S1. Warm rolling: Preheat a high silicon steel casting thin plate with a thickness of 1.5 mm to T 1 = 800 °C and keep it warm for 30 min, then warm roll it into a warm rolled plate with a thickness of 0.6 mm. Among them, the warm rolling temperature range is set to 600 - 750 °C, the total reduction ratio is 60%, the number of rolling passes is 3 passes, the reduction ratio R a1 of the first pass, the reduction ratio R a2 of the second pass, and the reduction ratio R a3 of the third pass are 33%, 25% and 20% respectively. When the strip exit temperature detected between passes is lower than 600 °C, reheat it to 800 °C in the furnace, keep it warm for 1.5 min and then continue rolling until it is rolled to 0.6 mm;

[0069] Anneal the warm rolled plate at T 2 = 850 °C, the annealing time t 2 = 20 min. After annealing, perform oil quenching and rapid cooling in the rapid bright quenching oil 7101 (produced by Yingji Lubrication Technology Co., Ltd.), and pickling to obtain an annealed warm rolled plate;

[0070] Among them, the main steps of pickling include: First, clean the surface of the warm rolled plate after oil quenching to remove impurities such as oil stains and dust to ensure the pickling effect. Subsequently, immerse the cleaned warm rolled plate in a hydrochloric acid aqueous solution with a concentration of about 20% for pickling treatment, and set the pickling time to 10 minutes. After pickling, rinse it with clean water to remove the residual acid solution and dissolved products on the surface to prevent the acidic residues from corroding the silicon steel. Finally, dry the warm rolled plate, clean it with anhydrous ethanol and store it in a container equipped with a desiccant to maintain its surface quality and prevent oxidation;

[0071] S2. Cold rolling: Preheat the annealed warm rolled plate after pickling to T 3After holding at 300°C for 7 minutes, it was cold-rolled into a cold-rolled sheet with a thickness of 0.09 mm. Among them, the temperature range of cold rolling was set from room temperature to 250°C, the total reduction ratio was 85%, the number of rolling passes was 4 passes, and the reduction ratio R b1 in the first pass was 40%, the reduction ratio R b2 in the second pass was 38%, and the reduction ratios R b3 and R b4 in the third and fourth passes were both 36%;

[0072] The cold-rolled sheet was annealed at T 4 = 850°C for an annealing time t 4 = 60 minutes to obtain an ultra-thin strip of high magnetic induction non-oriented high-silicon steel.

[0073] The microstructure texture of the ultra-thin strip of non-oriented high-silicon steel obtained in this example is as Figure 1 shown. From Figure 1 (a), the grains marked in blue are {111} (i.e., γ-line) grains. It can be seen that the proportion of unfavorable γ-line grains in this example is relatively low. In terms of grain size, there is no phenomenon of abnormal grain growth (i.e., the size of individual grains exceeds 10 times the average grain size), and the structure is relatively uniform. The same information can be obtained from Figure (1)b. The triangle of the inverse pole figure has a lower intensity at {111}, proving that the proportion of {111} grains is relatively small. Based on the uniform and moderately grown grain structure and the relatively low proportion of unfavorable γ-line grains, the magnetic properties of this example are as follows: the longitudinal magnetic induction B 50 = 1.656 T, the difference S 1 between the longitudinal and transverse magnetic inductions = -0.7%; the longitudinal iron loss P 1.0 / 400 = 12.7 W / kg, the difference S 2 between the longitudinal and transverse iron losses = -1.5%; where, S 1 = (longitudinal magnetic induction B 50 - transverse magnetic induction B 50 ) / longitudinal magnetic induction B 50 , S 2 = (longitudinal iron loss P 1.0 / 400 - transverse iron loss P 1.0 / 400 ) / longitudinal iron loss P 1.0 / 400 . Thus, it can be seen that this example can obtain an ultra-thin high-silicon steel sheet with a thickness ≤ 0.1 mm, which has excellent performance in magnetic properties, such as high magnetic induction, low iron loss, and low anisotropy degree, and has broad application prospects, especially in the field of manufacturing motor cores that require lightweight, miniaturization, and high efficiency.

[0074] Example 2

[0075] The difference between this embodiment and Embodiment 1 is as follows: In step S1, a high-silicon steel cast thin sheet with a thickness of 2.0 mm is warm-rolled into a warm-rolled sheet with a thickness of 0.6 mm. The total reduction ratio is 70%, the number of rolling passes is 4 passes, and the reduction ratio R a1 in the first pass is 35%, and the reduction ratios R a2 , R a3 , and R a4 in the second to fourth passes are 27%, 21%, and 20% respectively. The remaining steps and parameters are the same as those in Embodiment 1.

[0076] The microstructure texture of the non-oriented high-silicon steel ultra-thin strip obtained in this embodiment is as Figure 2 shown. From Figure 2 (a), the grains marked in blue are {111} (i.e., γ-line) grains. It can be seen that the proportion of unfavorable γ-line grains in this embodiment is relatively low. In terms of grain size, there is no phenomenon of abnormal grain growth (i.e., the size of individual grains exceeds 10 times the average grain size), and the structure is relatively uniform. The same information can be obtained from Figure (2)b. The triangle of the inverse pole figure has a lower intensity at {111}, proving that the proportion of {111} grains is relatively small.

[0077] Embodiment 3

[0078] The difference between this embodiment and Embodiment 1 is as follows: In step S1, a high-silicon steel cast thin sheet with a thickness of 1.0 mm is warm-rolled into a warm-rolled sheet with a thickness of 0.6 mm. The total reduction ratio is 40%, the number of rolling passes is 2 passes, and the reduction ratios R a1 , R a2 in the first and second passes are 25% and 20% respectively. The remaining steps and parameters are the same as those in Embodiment 1.

[0079] Embodiment 4

[0080] The difference between this embodiment and Embodiment 1 is as follows: In step S1, a high-silicon steel cast thin sheet with a thickness of 1.2 mm is warm-rolled into a warm-rolled sheet with a thickness of 0.6 mm. The total reduction ratio is 50%, the number of rolling passes is 2 passes, and the reduction ratio R a1 in the first pass is 30%, and the reduction ratio R a2 in the second pass is 28.6%. The remaining steps and parameters are the same as those in Embodiment 1.

[0081] Embodiment 5

[0082] The difference between this embodiment and Embodiment 1 is as follows: In step S1, the warm-rolling temperature range is set to 650 - 750 °C. When the strip exit temperature detected between passes is lower than 650 °C, it is reheated in the furnace. The remaining steps and parameters are the same as those in Embodiment 1.

[0083] Embodiment 6

[0084] The difference between this embodiment and Embodiment 1 lies in that: in step S1, the warm rolling temperature range is set to 700-750 °C. When the strip outlet temperature detected between passes is lower than 700 °C, it is reheated in the furnace. The remaining steps and parameters are the same as those in Embodiment 1.

[0085] Embodiment 7

[0086] The difference between this embodiment and Embodiment 1 lies in that: in step S1, the warm rolled plate is annealed at T 2 = 820 °C for an annealing time t 2 = 22 min, and after annealing, it is rapidly cooled by oil quenching in the environmentally friendly water-soluble quenching liquid 7201 (produced by Yingji Lubrication Technology). The remaining steps and parameters are the same as those in Embodiment 1.

[0087] Embodiment 8

[0088] The difference between this embodiment and Embodiment 1 lies in that: in step S1, the warm rolled plate is annealed at T 2 = 880 °C for an annealing time t 2 = 18 min. The remaining steps and parameters are the same as those in Embodiment 1.

[0089] Embodiment 9

[0090] The difference between this embodiment and Embodiment 1 lies in that: in step S1, the warm rolled plate is annealed at T 2 = 800 °C for an annealing time t 2 = 25 min. The remaining steps and parameters are the same as those in Embodiment 1.

[0091] Embodiment 10

[0092] The difference between this embodiment and Embodiment 1 lies in that: in step S1, the warm rolled plate is annealed at T 2 = 900 °C for an annealing time t 2 = 15 min. The remaining steps and parameters are the same as those in Embodiment 1.

[0093] Embodiment 11

[0094] The difference between this embodiment and Embodiment 1 lies in that: in step S2, a cold rolled plate with a thickness of 0.1 mm is produced by cold rolling, the total reduction ratio is 83%, the number of rolling passes is 4 passes, the reduction ratio R b1 in the first pass is 40%, and the reduction ratios R b2 , R b3 and R b4 in the second to fourth passes are 38%, 36% and 28.6% in sequence. The remaining steps and parameters are the same as those in Embodiment 1.

[0095] Embodiment 12

[0096] The difference between this embodiment and Embodiment 1 is as follows: In step S2, a cold-rolled sheet with a thickness of 0.06 mm is produced by cold rolling. The total reduction ratio is 90%, the number of rolling passes is 5, and the reduction ratios R b1 ~R b5 are 40%, 38%, 36%, 35% and 34% in sequence. The remaining steps and parameters are the same as those in Embodiment 1.

[0097] Embodiment 13

[0098] The difference between this embodiment and Embodiment 1 is as follows: In step S1, a high-silicon steel cast thin sheet with a thickness of 1.5 mm is warm-rolled into a warm-rolled sheet with a thickness of 0.5 mm. The total reduction ratio is 67%, the number of rolling passes is 4, and the reduction ratios R a1 ~R a4 are 33.3%, 25%, 20% and 16.7% in sequence; in step S2, a cold-rolled sheet with a thickness of 0.04 mm is produced by cold rolling. The total reduction ratio is 92%, the number of rolling passes is 5, and the reduction ratio R b1 in the first pass is 40%, and the reduction ratios R b2 ~R b5 from the second pass to the fifth pass are all 38%. The remaining steps and parameters are the same as those in Embodiment 1.

[0099] Embodiment 14

[0100] The difference between this embodiment and Embodiment 1 is as follows: In step S1, a high-silicon steel cast thin sheet with a thickness of 1.5 mm is warm-rolled into a warm-rolled sheet with a thickness of 0.5 mm. The total reduction ratio is 67%, the number of rolling passes is 4, and the reduction ratios R a1 ~R a4 are 30%, 25%, 20% and 20% in sequence; in step S2, a cold-rolled sheet with a thickness of 0.1 mm is produced by cold rolling. The total reduction ratio is 80%, the number of rolling passes is 4, and the reduction ratio R b1 in the first pass is 40%, the reduction ratio R b2 in the second pass is 38%, the reduction ratio R b3 in the third pass is 30%, and the reduction ratio R b4 in the fourth pass is 23%. The remaining steps and parameters are the same as those in Embodiment 1.

[0101] Embodiment 15

[0102] The difference between this embodiment and Embodiment 1 is as follows: In step S2, the temperature range of cold rolling is set to 100 - 250 °C. When the strip outlet temperature detected between passes is lower than 100 °C, it is reheated in the furnace. The remaining steps and parameters are the same as those in Embodiment 1.

[0103] Embodiment 16

[0104] The difference between this embodiment and Embodiment 1 lies in that: in step S2, the temperature range of cold rolling is set to 150 - 250°C. When the strip outlet temperature detected between passes is lower than 150°C, it is reheated in the furnace. The remaining steps and parameters are the same as those in Embodiment 1.

[0105] Embodiment 17

[0106] The difference between this embodiment and Embodiment 1 lies in that: in step S2, the cold-rolled plate is annealed at T 4 = 820°C, and the annealing time t 4 = 70 min. The remaining steps and parameters are the same as those in Embodiment 1.

[0107] Embodiment 18

[0108] The difference between this embodiment and Embodiment 1 lies in that: in step S2, the cold-rolled plate is annealed at T 4 = 880°C, and the annealing time t 4 = 50 min. The remaining steps and parameters are the same as those in Embodiment 1.

[0109] Embodiment 19

[0110] The difference between this embodiment and Embodiment 1 lies in that: in step S2, the cold-rolled plate is annealed at T 4 = 800°C, and the annealing time t 4 = 90 min. The remaining steps and parameters are the same as those in Embodiment 1.

[0111] Embodiment 20

[0112] The difference between this embodiment and Embodiment 1 lies in that: in step S2, the cold-rolled plate is annealed at T 4 = 900°C, and the annealing time t 4 = 45 min. The remaining steps and parameters are the same as those in Embodiment 1.

[0113] Embodiment 21

[0114] The difference between this embodiment and Embodiment 1 lies in that: before annealing in step S2, the cold-rolled plate is placed in an annealing furnace, and then the annealing furnace is heated to the annealing temperature T 4 = 850°C. The remaining steps and parameters are the same as those in Embodiment 1.

[0115] Comparative Example 1

[0116] The difference between this comparative example and Embodiment 1 lies in that: in step S1, a high-silicon steel casting thin plate with a thickness of 2.5 mm is hot-rolled into a hot-rolled plate with a thickness of 0.35 mm, the total reduction ratio is 86%, the number of rolling passes is 4 passes, and the reduction ratios R a1 、R a2 、Ra3 Both are 40%, and the reduction ratio R in the fourth pass a4 is 35%. In step S2, a cold-rolled sheet with a thickness of 0.09 mm is produced by cold rolling. The total reduction ratio is 74%, the number of rolling passes is 4, and the reduction ratio R in the first pass b1 is 40%, the reduction ratio R in the second pass b2 is 25%, the reduction ratio R in the third pass b3 is 25%, and the reduction ratio R in the fourth pass b4 is 23%. The remaining steps and parameters are the same as those in Example 1.

[0117] In Comparative Example 1, since the reasonable ratio of the total reduction ratios of warm rolling and cold rolling provided by the present invention is not adopted (that is, warm rolling from 1 - 3 mm to 0.5 - 0.7 mm and cold rolling from 0.5 - 0.7 mm to 0.1 mm or less), the magnetic properties and workability are inferior to those of the present invention. Specifically, the magnetic induction B 50 is lower, and the absolute value of the magnetic induction difference S 1 between the longitudinal and transverse directions is larger, that is, the degree of anisotropy is larger.

[0118] Comparative Example 2

[0119] The difference between this comparative example and Example 1 is that in step S1, a high-silicon steel cast thin sheet with a thickness of 1.0 mm is warm-rolled into a warm-rolled sheet with a thickness of 0.8 mm. The total reduction ratio is 20%, the number of rolling passes is 1, and the reduction ratio R a1 is 20%. In step S2, a cold-rolled sheet with a thickness of 0.09 mm is produced by cold rolling. The total reduction ratio is 89%, the number of rolling passes is 5, and the reduction ratio R in the first pass b1 is 40%, the reduction ratio R in the second pass b2 is 35%, the reduction ratio R in the third pass b3 is 35%, the reduction ratio R in the fourth pass b4 is 35%, and the reduction ratio R in the fifth pass b5 is 31%. The remaining steps and parameters are the same as those in Example 1.

[0120] In Comparative Example 2, since the appropriate range of the total reduction ratio of warm rolling provided by the present invention is not adopted (that is, warm rolling from 1 - 3 mm to 0.5 - 0.7 mm), the magnetic properties and workability are inferior to those of the present invention. Specifically, the magnetic induction B 50 is lower, the iron loss P 1.0 / 400 is on the high side, and the absolute value of the magnetic induction difference S 1 between the longitudinal and transverse directions increases, that is, the degree of anisotropy is larger.

[0121] Comparative Example 3

[0122] The difference between this comparative example and Example 1 is as follows: in step S1, the warm rolling temperature range is set to 500 - 590 °C. When the strip outlet temperature detected between passes is lower than 500 °C, it is reheated to 590 °C in the furnace. The remaining steps and parameters are the same as those in Example 1.

[0123] Since Comparative Example 3 does not adopt the preferred range of the warm rolling temperature provided by the present invention (i.e., 600 - 750 °C), its magnetic properties and processing performance are inferior to those of the present invention. Specifically, the magnetic induction B 50 is lower, and the iron loss P 1.0 / 400 is higher. Moreover, the absolute value of the magnetic induction difference S 1 between the longitudinal and transverse directions is larger, that is, the degree of anisotropy is larger.

[0124] The microstructure texture of the non-oriented high-silicon steel ultra-thin strip obtained in Comparative Example 3 is as Figure 3 shown. From Figure 3 (a), the blue-marked grains are {111} (i.e., γ-line) grains. It can be seen that in this comparative example, the proportion of unfavorable γ-line grains is relatively high. In terms of grain size, there are more small-sized grains, and the tissue uniformity is inferior to that of the embodiment of the present invention. The above points are all not conducive to reducing iron loss. The same information can be obtained from Figure (3)b. The triangle of the inverse pole figure has a higher intensity at {111}, proving that the proportion of {111} grains is relatively large.

[0125] Comparative Example 4

[0126] The difference between this comparative example and Example 1 is as follows: in step S1, the warm rolled plate is annealed at T 2 = 780 °C. The remaining steps and parameters are the same as those in Example 1.

[0127] Since Comparative Example 4 does not adopt the preferred range of the annealing temperature after warm rolling provided by the present invention (i.e., T 2 = 800 - 900 °C), its magnetic properties and processing performance are inferior to those of the present invention. Specifically, the magnetic induction B 50 is lower, and the iron loss P 1.0 / 400 is on the high side. Moreover, the absolute value of the magnetic induction difference S 1 between the longitudinal and transverse directions is larger, that is, the degree of anisotropy is larger.

[0128] Comparative Example 5

[0129] The difference between this comparative example and Example 1 is as follows: in step S1, the warm rolled plate is annealed at T 2 = 920 °C. The remaining steps and parameters are the same as those in Example 1.

[0130] Since Comparative Example 5 does not adopt the preferred range of the annealing temperature after warm rolling provided by the present invention (i.e., T 2 = 800 - 900 °C), its magnetic properties and processing performance are inferior to those of the present invention. Specifically, the magnetic induction B50 is lower, the iron loss P 1.0 / 400 is on the high side, and the magnetic induction difference S between the longitudinal and transverse directions 1 has a larger absolute value, that is, the degree of anisotropy is larger.

[0131] Comparative Example 6

[0132] The difference between this comparative example and Example 1 is that: in step S1, a high-silicon steel casting sheet with a thickness of 1.5 mm is warm-rolled into a warm-rolled sheet with a thickness of 0.3 mm, and the total reduction ratio is 80%. The reduction ratio R of the first pass a1 is 40%, and the reduction ratio R of the second pass a2 is 33.3%. The reduction ratios R of the third and fourth passes a3 and R a4 are both 30%; in step S2, it is cold-rolled into a cold-rolled sheet with a thickness of 0.1 mm, the total reduction ratio is 67%, and the number of rolling passes is 3. The reduction ratio R of the first pass b1 is 40%, the reduction ratio R of the second pass b2 is 28%, and the reduction ratio R of the third pass b3 is 23%. The remaining steps and parameters are the same as those in Example 1.

[0133] Since Comparative Example 6 does not adopt the preferred range of the total cold-rolling reduction ratio provided by the present invention (that is, rolling from 0.5 - 0.7 mm to ≤0.1 mm, and the total reduction ratio ≥80%), its magnetic properties and processing properties are inferior to those of the present invention. Specifically, the magnetic induction B 50 is lower, and the absolute value of the magnetic induction difference S between the longitudinal and transverse directions 1 is larger, that is, the degree of anisotropy is larger.

[0134] The microstructure texture of the non-oriented high-silicon steel ultra-thin strip obtained in Comparative Example 6 is as shown in Figure 4 . From Figure 4 (a), the blue-marked grains are {111} (i.e., γ-line) grains. It can be seen that in this comparative example, the proportion of unfavorable γ-line grains is relatively high; the same information can be obtained from Figure (4)b. The triangle of the inverse pole figure has a higher intensity at {111}, proving that the proportion of {111} grains is relatively large.

[0135] Comparative Example 7

[0136] The difference between this comparative example and Example 1 is that: in step S2, the cold-rolling temperature is set at room temperature. The remaining steps and parameters are the same as those in Example 1.

[0137] Since Comparative Example 7 does not adopt the warm cold-rolling temperature range provided by the present invention (that is, room temperature - 250°C), its processing performance is inferior to that of the present invention. Specifically, edge cracking occurs in the strip during the rolling process.

[0138] Comparative Example 8

[0139] The difference between this comparative example and Example 1 is that: in step S2, the cold-rolled sheet is annealed at T 4 = 780 °C. The remaining steps and parameters are the same as those in Example 1.

[0140] In Comparative Example 8, since the preferred range of the annealing temperature after cold rolling provided by the present invention is not adopted (i.e., T 4 = 800 - 900 °C), the magnetic properties and workability are inferior to those of the present invention. Specifically, the magnetic induction B 50 is on the low side, the iron loss P 1.0 / 400 is relatively high, and the absolute value of the difference in magnetic induction between the longitudinal and transverse directions S 1 is larger, that is, the degree of anisotropy is larger.

[0141] Comparative Example 9

[0142] The difference between this comparative example and Example 1 is that: in step S2, the cold-rolled sheet is annealed at T 4 = 920 °C. The remaining steps and parameters are the same as those in Example 1.

[0143] In Comparative Example 9, since the preferred range of the annealing temperature after cold rolling provided by the present invention is not adopted (i.e., T 4 = 800 - 900 °C), the magnetic properties and workability are inferior to those of the present invention. Specifically, the magnetic induction B 50 is relatively low, the iron loss P 1.0 / 400 is on the high side, and the absolute values of the difference in magnetic induction between the longitudinal and transverse directions S 1 and the difference in iron loss S 2 are larger, that is, the degree of anisotropy is larger.

[0144] Comparative Example 10

[0145] The difference between this comparative example and Example 1 is that: the warm-rolled annealed sheet is not subjected to oil quenching treatment, and the remaining steps and parameters are the same as those in Example 1.

[0146] In Comparative Example 10, since the preferred operation steps provided by the present invention are not adopted (i.e., oil quenching after annealing in step S1), the workability is inferior to that of the present invention. Specifically, it breaks during the rolling process.

[0147] In order to more clearly show the parameter variables and performance test results of the above examples and comparative examples, refer to Table 1 and Table 2. As can be seen from Table 1 and Figure 1-2 it can be seen that Examples 1 - 21, by adopting the preparation method provided by the present invention, while ensuring good workability, effectively suppress the formation of unfavorable γ - fiber (plate normal ND / / <111>) texture, obtain uniform and appropriately sized grain structures, and achieve high magnetic induction B 50 ≥ 1.62 T and low iron loss P1.0 / 400 <15 W / kg, so that the obtained ultra-thin high-silicon steel strip can exhibit excellent magnetic properties in all directions, and has good processability. The obtained non-oriented high-silicon steel strip is not only very thin in thickness, but also has no defects such as cracking, and the overall quality is good.

[0148] From Table 2 and Figure 3-4 It can be seen that, in contrast, the anisotropy degree of Comparative Examples 1-10 is relatively large, the magnetic induction is relatively high, and the overall magnetic properties are inferior to those of the present invention. Moreover, the processability of some comparative examples is poor, and even edge cracking and fracture phenomena occur. And the unfavorable γ-ray texture accounts for a relatively large proportion in the microstructure, and the grain tissue uniformity is inferior to that of the present invention. Thus, it can be seen that due to the failure to adopt the preferred process steps and parameters provided by the present invention, the overall magnetic properties, processability, and product quality of Comparative Examples 1-10 have declined.

[0149] Table 1: Specific process parameters and performance results in the preparation methods of Examples 1-21

[0150]

[0151]

[0152]

[0153] Table 2: Specific process parameters and performance results in the preparation methods of Comparative Examples 1-10

[0154]

[0155]

[0156] The above is only the preferred specific implementation manners of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a high magnetic induction non-oriented high silicon steel ultra-thin strip, characterized in that: The following steps are involved: S1, warm rolling: preheat the high silicon steel cast sheet with a thickness H0 of 1 to 3 mm to a temperature T1 = 780 to 850 ° C, and warm roll it into a warm rolled sheet with a thickness H1 of 0.5 to 0.7 mm. The temperature range of warm rolling is set to 725 to 750 ° C. The temperature is returned to the furnace between passes and heated to T1 for 1 to 2 minutes to ensure that the warm rolling temperature is within the set range; The total reduction rate R of the warm rolling a 50-70%; The warm rolled sheet is annealed at an annealing temperature of T2 = 820-880°C and an annealing time of t2 = 15-25 min. After annealing, the sheet is oil quenched and pickled to obtain an annealed warm rolled sheet. After annealing, the sheet is rapidly cooled by oil quenching to effectively inhibit the formation of a partially ordered phase B2 and inhibit the transformation of the B2 phase to the DO3 phase, thereby improving the subsequent cold rolling plasticity. S2, cold rolling: preheat the annealed warm-rolled sheet to a temperature of T3 = 290-310°C, and cold-roll the sheet to a thickness of H2 ≤ 0.1 mm. The cold rolling temperature range is set at 100-250°C, and the sheet is returned to the furnace between passes and heated to T3, but no insulation is required; the total reduction rate R of the cold rolling is b 80-92%; The cold-rolled sheet is annealed at an annealing temperature of T4 = 820-880°C. Before annealing, the annealing furnace is first heated to T4, and then the cold-rolled sheet is placed therein. The annealing time is t4 = 45-90 minutes, and a high magnetic induction non-oriented high silicon steel ultra-thin strip is obtained. The thickness of the high magnetic induction non-oriented high silicon steel ultra-thin strip is ≤0.1mm, and the magnetic induction B 50 ≥1.62T, iron loss P 1.0 / 400 <15W / kg, the absolute value of the longitudinal and transverse difference of magnetic induction S1 is <2.0%, and the absolute value of the longitudinal and transverse difference of iron loss S2 is <2.0%; where S1 = (longitudinal magnetic induction B 50 - Transverse magnetic induction B 50 ) / longitudinal magnetic induction B 50 , S2=(longitudinal iron loss P 1.0 / 400 - Transverse iron loss P 1.0 / 400 ) / longitudinal iron loss P 1.0 / 400 .

2. The preparation method according to claim 1, characterized in that: In step S1, the rolling pass number M is 2 to 4, and the reduction rate R of each pass is a1 To R aM Controlled between 20% and 35%.

3. The preparation method according to claim 1, characterized in that: In step S2, the rolling pass number N is 3 to 5, and the reduction rate R of each pass is b1 To R bN Controlled between 15 and 40%.

4. The preparation method according to claim 3, characterized in that: In step S2, the first pass reduction rate R of the cold rolling is b1 Controlled at 35-40%, the subsequent pass reduction rate R b2 To R bN Controlled between 15 and 38%.

5. The preparation method according to claim 1, characterized in that: In step S1, the annealing time t2=18-22 min; and / or, in step S2, the annealing time t4=50-70 min.

6. The preparation method according to claim 1, characterized in that: T1 = 780-820°C; and / or, T3 = 295-305°C.

7. The preparation method according to claim 1, characterized in that: In step S1, the preheating to temperature T1 is followed by heat preservation, and the heat preservation time t1 is 20 to 40 minutes; and / or, in step S2, the preheating to temperature T3 is followed by heat preservation, and the heat preservation time t3 is 5 to 10 minutes.

8. An ultra-thin strip of high magnetic induction non-oriented high silicon steel obtained by the preparation method as described in any one of claims 1 to 7.

9. Use of the high magnetic induction non-oriented high silicon steel ultra-thin strip obtained by the preparation method according to any one of claims 1 to 7 or the high magnetic induction non-oriented high silicon steel ultra-thin strip according to claim 8 in a motor.

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