Ultrathin non-oriented silicon steel strip and preparation method thereof

Abstract

The invention relates to an ultrathin non-oriented silicon steel strip and a preparation method thereof, and belongs to the technical field of non-oriented silicon steel. At least one of the following problems existing in an existing ultrathin non-oriented silicon steel strip and a preparation method thereof is solved: the magnetic performance is difficult to reach a high standard, the product quality is difficult to guarantee while the thickness is reduced, and the preparation process is relatively tedious. The invention relates to an ultrathin non-oriented silicon steel strip, the thickness tf of the strip is less than or equal to 0.10 mm, and the texture type comprises a higher content of lambda-line ({001} lt; hk0gt; hk0gt; ), [eta]-line ({0kl} lt; 100 gt; ), lt; 115gt, 115gt; / / ND, and low-content gamma-line (ND / / lt; 111gt, 111gt; and texturing. According to the ultrathin non-oriented silicon steel strip and the preparation method thereof, high magnetic induction, low iron loss, ultrathin thickness and good mechanical property and surface quality are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of non-oriented silicon steel, and in particular to an ultra-thin non-oriented silicon steel strip and a preparation method thereof. Background Art

[0002] Ultra-thin non-oriented silicon steel usually refers to iron-silicon alloy strips with a thickness of 0.10 mm or less, which are mainly used in medium and high frequency conditions of 400 Hz and above. As an excellent soft magnetic material, it is widely used in core materials in power electronics, military industry, new energy vehicles and other fields. In order to meet the needs of high efficiency, high speed, high power density and lightweight, it is required to have the characteristics of low loss in medium and high frequency, high magnetic induction and ultra-thinness.

[0003] At present, the preparation methods of non-oriented silicon steel strip mainly include the following: traditional process (smelting-hot rolling-normalizing-cold rolling-annealing-coating), twin-roll continuous casting, plane flow casting, etc. However, the existing preparation methods and the silicon steel strip products obtained therefrom have the following bottlenecks and problems: it is difficult to achieve high standards for magnetic properties, such as high magnetic induction (magnetic induction B 5000 >1.6T) and low iron loss (P 1.0 / 400 <11W / kg,P 1.0 / 1000 <35W / kg), it is difficult to reduce the thickness (such as 0.03~0.08mm) while ensuring the product quality, and the preparation process is relatively complicated. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide an ultra-thin non-oriented silicon steel strip and a method for preparing the same, so as to solve at least one of the following problems existing in the existing non-oriented silicon steel strip products and methods for preparing the same: (1) It is difficult to achieve high magnetic properties, such as high magnetic induction (magnetic induction B 5000 >1.6T) and low iron loss (P 1.0 / 400 <11W / kg,P 1.0 / 1000 <35W / kg); (2) It is difficult to reduce the thickness while ensuring product quality; (3) The preparation process is relatively complicated.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] The present invention provides an ultra-thin non-oriented silicon steel strip, the thickness of which is t f ≤0.10 mm, the texture type of the tape includes a high content of λ-lines ({001} <hk0>), η-line ({0kl} <100> ), <115> / / NDThese three textures, as well as the lower content of γ-rays (ND / / <111> )Texture;

[0007] Among them, the λ-line ({001} <hk0>) texture content is 10.8% to 25.8%, η-line ({0kl} <100> ) Texture content is 13.2% to 50.5%, <115> / / ND texture content is 31.4% to 52.8%; γ-ray (ND / / <111> )Texture content is 12.9% to 19.9%.

[0008] Furthermore, the number of grain layers of the side structure of the strip is 1-2 layers, and the grain structure of the strip is equiaxed grains.

[0009] Furthermore, the total average grain size of the strip is 27 μm to 74 μm; wherein the λ-line ({001} <hk0>), η-line ({0kl} <100> ), <115> / / ND The average grain size of any of the three textures is ≥ the total average grain size, γ-line (ND / / <111> )The average grain size of the texture is ≤ the overall average grain size.

[0010] Furthermore, the λ-line ({001} <hk0>) texture includes Cube({001} <100> )、{001} <110> , {001} <120> The three orientation components; and / or,

[0011] η-line ({0kl} <100> ) textures include Goss ({011} <100> ), {210} <001> These two orientation components.

[0012] Furthermore, the thickness of the strip t f 0.03mm~0.08mm; when 0.03mm≤t f <0.05mm, the yield strength of the strip R e ≥350MPa, tensile strength R m ≥400Mpa; when 0.05mm≤t f ≤0.08mm, yield strength of strip R e ≥450MPa, tensile strength R m ≥500Mpa.

[0013] Furthermore, the magnetic properties of the strip in all directions can reach: magnetic induction intensity B 5000 ≥1.66T, iron loss P 1.0 / 400 <10.8W / kg,P 1.0 / 1000 <22.7W / kg.

[0014] Furthermore, the λ-line ({001} <hk0>) texture content is 15.0% to 25.8%, η-line ({0kl} <100> ) Texture content is 32.1% to 50.5%, <115> / / ND texture content is 39.9% to 51.4%; γ-ray (ND / / <111> ) Texture content is 12.9% to 18.4%;

[0015] The magnetic induction intensity B of the strip in all directions 5000 ≥1.73T.

[0016] Furthermore, the strip includes: small-angle grain boundaries of 2°≤α≤15° accounting for 19.5% to 34.7% of the grain boundaries, and large-angle grain boundaries of α>45° accounting for 18.9% to 33.4% of the grain boundaries; α is the orientation difference between adjacent grains.

[0017] The present invention also provides a method for preparing the ultra-thin non-oriented silicon steel strip as described above, comprising the following steps:

[0018] S1, select the initial thickness t 0 The non-oriented silicon steel sheet with a thickness of 0.15 to 0.35 mm is used as the base material, and the average grain size of the base material is 50 to 180 μm;

[0019] S2, cold rolling the base material at room temperature, and cold rolling the base material for multiple passes to obtain the final thickness t f Cold-rolled ultra-thin strip ≤0.1mm;

[0020] S3. Annealing the cold-rolled ultra-thin strip.

[0021] Further, in step S2, the cold-rolled ultra-thin strip is 2 =45° ODF cross-section intensity level: λ-line ({001} <hk0>) texture ≥ α* line texture > γ-line (ND / / <111> ) texture, and the λ-line texture contains strong Cube ({001} <100> ) texture, the strength level of Cube texture is ≥2.

[0022] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0023] (1) The ultra-thin non-oriented silicon steel strip provided by the present invention has high magnetic induction and low iron loss in medium and high frequencies, such as magnetic properties in all directions can reach: B 5000 ≥1.66T, B for most examples 5000 Can reach above 1.70, P 1.0 / 400 <10.8W / kg,P 1.0 / 1000 <22.7W / kg, the above excellent magnetic properties are attributed to its specific texture characteristics, which include: a relatively high and appropriate content of λ-line ({001} <hk0>) and η-line ({0kl} <100> ), <115> / / ND these three textures, and γ-line (ND / / <111> ) texture content is low, especially, <115> / / ND This specific crystal orientation has a positive effect on magnetic properties. The strip includes 31.4% to 52.8% <115> / / ND texture is beneficial to improving its magnetic properties.

[0024] (2) In some preferred embodiments, the thickness of the strip product provided by the present invention can be very thin (0.03-0.08 mm), while the product quality is good and the mechanical properties are excellent. For example, when 0.03 mm ≤ t f <0.05mm, the yield strength R of the strip e ≥350MPa, tensile strength R m ≥400Mpa; when 0.05mm≤t f ≤0.08mm, the yield strength of the strip R e ≥450MPa, tensile strength R m ≥500Mpa.

[0025] (3) In some preferred embodiments, the strip of the present invention has specific microscopic grain characteristics: the number of side grain layers is 1-2 layers, and the grain structure is equiaxed crystals, which helps to further improve the magnetic properties of the strip and achieve high magnetic induction and low iron loss in all directions.

[0026] (4) In some preferred embodiments, when the strip of the present invention has a specific microstructure, such as λ-line, η-line, <115> / / NDThe average grain size of any of the three favorable textures is greater than or equal to the total average grain size, while the average grain size of the unfavorable γ-line texture is less than or equal to the total average grain size, and the total average grain size is within the preferred range, which is beneficial to improving the magnetic properties, for example, further improving the magnetic induction.

[0027] (5) In some preferred embodiments, when the favorable texture in the tape of the present invention, such as λ-line ({001} <hk0>), η-line ({0kl} <100> ) each include specific oriented components, their magnetic properties can be optimized and the magnetic induction can be further improved.

[0028] (6) In some preferred embodiments, when the favorable textures in the tape of the present invention, such as λ-line, η-line, <115> / / When the ND content is within a more preferred range and the unfavorable γ-line texture is controlled within a certain lower range, it is helpful to further improve the magnetic properties of the strip and achieve high magnetic induction and low iron loss. For example, the magnetic induction intensity B of the strip in each direction can be 5000 ≥1.73T.

[0029] (7) In some preferred embodiments, by controlling the proportion of grain boundaries with different phase differences in the strip to meet certain preferred conditions (including: small-angle grain boundaries of 2°≤α≤15° with a grain boundary proportion of 19.5% to 34.7%, and large-angle grain boundaries of α>45° with a grain boundary proportion of 18.9% to 33.4%), a strip with better mechanical properties can be obtained.

[0030] (8) The preparation method provided by the present invention is simple to operate and has a short process flow. As an economical and efficient method, it is suitable for manufacturing ultra-thin non-oriented silicon steel strips.

[0031] (9) In the preparation method of the present invention, by controlling the micro-texture strength level of the cold-rolled ultra-thin strip, it is helpful to obtain a strip product with a higher strength favorable texture and a lower strength unfavorable texture, thereby optimizing its magnetic properties and further improving the magnetic induction.

[0032] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0034] Figure 1 These are actual photos of ultra-thin non-oriented silicon steel strips according to the embodiments of the present invention, (a) is Embodiment 1-1, (b) is Embodiment 1-2, and (c) is Embodiment 9-2;

[0035] Figure 2 The present invention provides a flow chart of the preparation method. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0037] Existing silicon steel strip products have at least one of the following problems: their magnetic properties often fail to meet high-end standards; it is difficult to achieve extremely thin thickness while maintaining quality and mechanical properties; and the existing preparation process is relatively complex. These problems limit the performance of silicon steel strip in applications that pursue high efficiency, high speed, high power density, and lightweight.

[0038] Based on this, in the first aspect, the present invention provides an ultra-thin non-oriented silicon steel strip, the thickness of the strip is t f ≤0.10 mm, the texture type of the strip includes a relatively high content of λ-lines ({001} <hk0>), η-line ({0kl} <100> ), <115> / / NDThese three textures, as well as the lower content of γ-rays (ND / / <111> )Texture;

[0039] Among them, the λ-line ({001} <hk0>) texture content is 10.8% to 25.8%, η-line ({0kl} <100> ) Texture content is 13.2% to 50.5%, <115> / / ND texture content is 31.4% to 52.8%; γ-ray (ND / / <111> )Texture content is 12.9% to 19.9%.

[0040] Compared with the prior art, the ultra-thin non-oriented silicon steel strip provided by the present invention has high magnetic induction and low medium and high frequency iron loss, for example: 5000 ≥1.66T, B for most examples 5000 Can reach above 1.70, P 1.0 / 400 <10.8W / kg,P 1.0 / 1000 <22.7W / kg, the above excellent magnetic properties are attributed to its specific texture characteristics, including: a relatively high and appropriate content of λ-line ({001} <hk0>) and η-line ({0kl} <100> ), <115> / / ND these three textures, and γ-line (ND / / <111> ) texture content is low, especially, <115> / / ND This specific texture has a positive effect on magnetic properties. The strip includes 31.4% to 52.8% <115> / / ND texture is beneficial to improving its magnetic properties.

[0041] Based on the above-mentioned specific texture characteristics, the magnetic properties of the strip provided by the present invention in each direction can reach: magnetic induction intensity B 5000 ≥1.66T, iron loss P 1.0 / 400 <10.8W / kg,P 1.0 / 1000 <22.7W / kg.

[0042] Preferably, the λ-line ({001} <hk0>) texture content is 15.0% to 25.8%, η-line ({0kl} <100> ) Texture content is 32.1% to 50.5%, <115> / / ND texture content is 39.9% to 51.4%; γ-ray (ND / / <111> ) texture content is 12.9% to 18.4%; Based on the preferred content of the above-mentioned specific texture, the magnetic induction intensity B of the strip in each direction 5000 ≥1.73T. When the strip includes favorable textures such as λ-line, η-line, <115> / / When the ND content is within the above preferred range and the unfavorable γ-line texture is controlled within a certain lower range, it helps to further improve the magnetic properties of the strip and achieve higher magnetic induction and low iron loss.

[0043] Furthermore, the thickness of the strip of the present invention can be thinner, that is, the thickness of the strip is t f It is 0.03mm~0.08mm.

[0044] Furthermore, when the strip is very thin, it also has high mechanical properties; for example, when 0.03 mm ≤ t f <0.05mm, the yield strength R of the strip e ≥350MPa, tensile strength R m ≥400Mpa; when 0.05mm≤t f ≤0.08mm, the yield strength of the strip R e ≥450MPa, tensile strength R m ≥500Mpa.

[0045] Preferably, the strip includes: small-angle grain boundaries of 2°≤α≤15° with a grain boundary ratio of 19.5% to 34.7%, and large-angle grain boundaries of α>45° with a grain boundary ratio of 18.9% to 33.4%; α is the orientation difference between adjacent grains. When the proportion of grain boundaries with different phase differences in the strip meets the above preferred conditions, a strip with better mechanical properties can be obtained. For example, when 0.03mm≤t f ≤0.05mm, the yield strength of the strip R e ≥380MPa, tensile strength R m ≥440Mpa; when 0.05mm≤t f ≤0.08mm, the yield strength of the strip R e >450MPa, tensile strength R m ≥530Mpa. Based on the above-mentioned preferred conditions for the grain boundary ratio, as the grain boundary ratio increases, it is beneficial to obtain a higher strength strip.

[0046] Preferably, the side structure of the strip has 1-2 layers of grains, and the grain structure of the strip is equiaxed. This microstructure helps to further improve the magnetic properties of the strip and achieve high magnetic induction and low iron loss in all directions. Specifically, (1) Improve magnetic induction: equiaxed grain structure and 1-2 layers of grains help to increase the consistency of arrangement of magnetic domains inside the material, thereby improving magnetic induction (magnetic flux density), so that the strip can conduct magnetic flux more effectively during magnetization; (2) Reduce iron loss: equiaxed grain structure and 1-2 layers of grains help to reduce iron loss caused by domain wall oscillation, thereby optimizing the high-frequency characteristics of the strip.

[0047] Preferably, the total average grain size of the strip is 27 μm to 74 μm; wherein the λ-line ({001} <hk0>), η-line ({0kl} <100> ), <115> / / ND The average grain size of any of the three textures is ≥ the total average grain size. The γ-line (ND / / <111> ) The average grain size of the texture is ≤ the total average grain size. When the strip of the present invention has a specific microstructure texture, such as λ-line, η-line, <115> / / NDThe average grain size of any of the three favorable textures is greater than or equal to the total average grain size, while the average grain size of the unfavorable γ-line texture is less than or equal to the total average grain size, and the total average grain size is within the preferred range, which is beneficial to improving the magnetic properties, further improving the magnetic induction, and also helping to reduce iron loss.

[0048] Furthermore, when the total average grain size of the strip is 27 μm to 74 μm, as the total average grain size decreases, it is beneficial to obtain a strip with higher strength.

[0049] Preferably, the λ-line ({001} <hk0>) texture includes Cube({001} <100> )、{001} <110> , {001} <120> These three orientation components; and / or, the η-line ({0kl} <100> ) textures include Goss ({011} <100> ), {210} <001> These two oriented components. When the favorable texture such as λ-line ({001} <hk0>), η-line ({0kl} <100> ) each include a specific orientation component, the magnetic properties can be optimized and the magnetic induction can be further improved. Specifically, when favorable textures such as λ-line and η-line include the above-mentioned specific orientation components, the movement resistance of the magnetic domain wall can be reduced, making the magnetization process smoother, thereby improving the magnetic induction, and a more regular magnetic domain structure can be formed. This regular magnetic domain structure helps to reduce the chaos and mutual interference of the magnetic domain wall, thereby reducing iron loss.

[0050] In some possible designs, the chemical composition of the strip includes, by mass percentage: Si: 2.0-3.5%, Al: 0.2-1.0%, Mn: 0.05-0.5%, and the rest is Fe and unavoidable impurities; wherein the sum of the Si and Al element contents satisfies 2.5%≤{[Si]+[Al]}≤4.5%.

[0051] In a second aspect, the present invention further provides a method for preparing the ultra-thin non-oriented silicon steel strip as described in the first aspect, comprising the following steps:

[0052] S1, select the initial thickness t 0 A non-oriented silicon steel sheet with a thickness of 0.15 to 0.35 mm is used as a base material, and the average grain size of the base material is 50 to 180 μm;

[0053] S2, cold rolling the base material at room temperature to obtain a final thickness t through multiple cold rolling passes. f Cold-rolled ultra-thin strip ≤0.1mm;

[0054] S3, annealing the cold-rolled ultra-thin strip.

[0055] Compared with the prior art, the preparation method provided by the present invention is simple to operate and has a short process flow. As an economical and efficient method, it is suitable for manufacturing ultra-thin non-oriented silicon steel strips.

[0056] Preferably, in step S1, the initial texture type of the base material includes λ-line ({001} <hk0>), η-line ({0kl} <100> )、Cube({001} <100> )、Goss({011} <100> ), {115} <161> 、{114} <481> ,γ-ray(ND / / <111> )At least two of the seven texture components.

[0057] In some preferred embodiments, in step S2, the final thickness t f Preferably, the total deformation of cold rolling is 46% to 92%, wherein the deformation of the first cold rolling is controlled at 30% to 60%, and the deformation of the second cold rolling is controlled at 20% to 40%.

[0058] Preferably, in step S3, the annealing temperature is 700-1000° C., the annealing time is 10-60 min, and the annealing atmosphere is hydrogen or a mixture of hydrogen and nitrogen.

[0059] Based on the preparation method of the present invention, further by screening a base material with a specific microtexture, and / or selecting appropriate rolling process parameters and / or controlling annealing process parameters, it is beneficial to prepare an ultra-thin non-oriented silicon steel strip with excellent magnetic properties; specifically, by at least one of the following preferred methods: (a) using a non-oriented silicon steel plate with a characteristic initial structure as the base material, (b) controlling the reasonable ratio of the total deformation amount of the cold rolling process, the first cold rolling deformation amount and the second cold rolling deformation amount, (c) selecting a suitable annealing temperature and time as well as an annealing atmosphere, it is helpful to improve the magnetic induction and reduce the medium and high frequency iron loss, obtain higher mechanical properties and improve the surface quality.

[0060] Preferably, in step S2, the cold-rolled ultra-thin strip is 2 =45° ODF cross-section intensity level: λ-line ({001} <hk0>) texture ≥ α* line texture > γ-line (ND / / <111> ) texture, and the λ-line texture contains strong Cube ({001} <100> ) texture, the strength level of Cube texture is ≥ 2. By controlling the micro texture strength level of the cold-rolled ultra-thin strip, it is helpful to obtain a strip product with a higher strength favorable texture and a lower strength unfavorable texture, thereby optimizing its magnetic properties and further improving the magnetic induction.

[0061] It should be noted that in step S1, (1) the thickness of the selected base material is between 0.15 and 0.35 mm. This thickness range can adapt to different cold rolling mills and process requirements, providing flexibility for production. (2) The average grain size is 50 to 180 μm, which can ensure that the base material can form a shear band after a certain cold rolling deformation. The formation of the shear band increases the nucleation probability of the easily magnetized grains, promotes grain refinement and increases dislocation density, which helps to improve the magnetic properties and mechanical properties of the material. (3) Selecting a base material with a suitable initial texture type can ensure that it can obtain a good "precursor" after the cold rolling deformation process, which helps to improve the magnetic properties, mechanical properties, and organizational uniformity.

[0062] It can be understood that in step S2, the thinner the base material, the fewer rolling passes are used, but the rolling ratio of the first two passes remains almost unchanged, that is, rolling according to the preferred pass ratio of controlling the deformation of the first cold rolling pass at 30% to 60% and the deformation of the second cold rolling pass at 20% to 40% can improve the magnetic properties, improve the mechanical properties, improve the isotropy of the material, and optimize the uniformity of the microstructure; specifically, (1) improving the magnetic properties: a larger deformation of the first pass helps to form a nucleus that is conducive to the easy magnetization texture and to form a favorable environment for the recovery and recrystallization of the nucleus, while a smaller deformation of the second pass helps to adjust the storage energy distribution. A reasonable deformation ratio (1) Improve mechanical properties: The appropriate deformation ratio is conducive to the reasonable distribution of storage energy in the steel strip during cold rolling, and provides conditions for the formation of a reasonable grain structure for annealing treatment. The grain size is small and evenly distributed, which can improve the yield strength and tensile strength of the steel strip. (2) Improve isotropy and organizational uniformity: A reasonable rolling ratio promotes the formation of more linear textures, which helps to reduce the anisotropy of the material, so that the steel strip has low anisotropy in the longitudinal and transverse directions.

[0063] Exemplarily, the deformation amount of the first cold rolling is 35%, 40%, 45%, 50%, and 55%; the deformation amount of the second cold rolling is controlled at 23%, 25%, 27%, 30%, 33%, 35%, and 38%.

[0064] It can be understood that in the production process of ultra-thin non-oriented silicon steel strip, annealing process is one of the key steps, which has a significant impact on the evolution of grain structure and texture. In step S3, by selecting a suitable annealing temperature (e.g., 700-1000°C) and annealing time (e.g., 10-60 minutes), and using an annealing atmosphere containing hydrogen, it is beneficial to improve magnetic properties, mechanical properties, isotropy and surface quality. Specifically, (1) improving magnetic properties: adopting the above-mentioned suitable annealing temperature and annealing time can improve grain structure and texture, form grain structure and texture that are beneficial to magnetic properties, thereby improving magnetic induction and reducing iron loss; (2) improving mechanical properties: adopting the above-mentioned suitable annealing process parameters can ensure that the material undergoes uniform recrystallization during the annealing process, optimize the grain size and shape, and improve the mechanical properties of the material; (3) improving isotropy and surface quality: adopting the above-mentioned suitable annealing process parameters can help reduce the anisotropy of the steel strip, making the magnetic properties and mechanical properties more consistent in different directions. The annealing atmosphere containing hydrogen can reduce the oxidation of the steel strip surface, maintain the chemical composition of the material and improve the surface quality.

[0065] Exemplarily, the annealing temperature is 750°C, 775°C, 800°C, 825°C, 850°C, 875°C, 900°C, 925°C, 950°C, 975°C, and the annealing time is 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min.

[0066] Exemplarily, in step S3, a multifunctional heat treatment furnace is used for annealing, which facilitates the adjustment of annealing temperature, annealing time and annealing atmosphere. Ultra-thin strips with excellent performance can be obtained by adjusting the annealing process.

[0067] Specifically, in step S1, the grain structure of the selected parent material is equiaxed crystal. Equiaxed crystal means that the grains in the material are roughly the same size in all directions and have no obvious directional characteristics. This organizational morphology has the following advantages in the preparation of ultra-thin non-oriented silicon steel: improving magnetic induction and reducing iron loss, improving processability, and enhancing isotropy.

[0068] Preferably, the side structure of the parent material has 1-3 layers of grains, and at least 25% of the grains penetrate the thickness of the parent material (i.e., the number of grains that penetrate the thickness of the parent material accounts for ≥ 25%) to ensure that the average grain size reaches half of the entire thickness of the parent material or more. Exemplarily, the side structure of the parent material may include 1 layer, 2 layers, and 3 layers, or 1 layer and 2 layers, or 1 layer and 3 layers; the number of grains in one layer may account for 30%, 40%, 50%, 60%, 70%, 80%, or 90%.

[0069] It can be understood that the selected base material has 1-3 layers of grains and at least 25% of the grains penetrate the thickness of the base material, which has the following benefits in terms of improving magnetic induction and reducing iron loss: 1) Improving magnetic induction: The penetration characteristics of the grains help to form a continuous magnetic flux path, reduce magnetic resistance, and thus improve the magnetic induction intensity of the material; 2) Reducing iron loss: Larger grain size and fewer grain boundaries can reduce grain boundary scattering, reduce losses during the magnetization process, and thus reduce iron loss; 3) Improving isotropy: The penetration of grains in the thickness direction helps to reduce the anisotropy of the material, improve the performance consistency of the steel strip, and also help to improve the formation of favorable textures in subsequent cold rolling and the uniformity of the structure after annealing.

[0070] In some preferred embodiments, the initial texture type of the parent material belongs to at least one of the following 12 situations:

[0071] (1)λ-line +η-line texture;

[0072] (2)λ-line+{115} <161> Texture;

[0073] (3) η-line + {115} <161> Texture;

[0074] (4){115} <161> +γ-line texture;

[0075] (5) Goss+Cube texture;

[0076] (6){115} <161> +Goss texture;

[0077] (7)λ-line +η-line +γ-line texture;

[0078] (8)λ-line+η-line+{115} <161> Texture;

[0079] (9) Goss+Cube+{115} <161> Texture;

[0080] (10) Goss+Cube+{115} <161> +γ-line texture;

[0081] (11)λ-line+{115} <161> +{114} <481> +γ-line texture;

[0082] (12)λ-line+{114} <481> +γ-line texture.

[0083] The inventors of the present invention have found in their research that the use of the above 12 kinds of base materials with characteristic initial structures is conducive to further improving the magnetic properties and mechanical properties, and also has better structural uniformity and surface quality.

[0084] Further preferably, based on these 12 characteristic initial structures, by selecting a base material with a suitable thickness and average grain size, and after a carefully designed cold rolling and annealing process, it can be transformed into a high-quality ultra-thin non-oriented silicon steel strip with excellent magnetic properties. The following are some preferred implementations:

[0085] a) When the initial texture type of the base material belongs to at least one of the following seven situations (1), (2), (3), (5), (6), (8), and (9), in step S1, the initial thickness t 0 The thickness of the steel sheet is 0.15-0.20 mm, and the average grain size is 80-100 μm; in step S2, the deformation of the first cold rolling is controlled at 40%-50%, and the deformation of the second cold rolling is controlled at 20%-25%; in step S3, the annealing temperature is 800-850° C., and the annealing time is 20-30 min.

[0086] b) When the initial texture type of the base material belongs to case (4) or (7), in step S1, the initial thickness t 0 The thickness of the steel sheet is 0.25-0.30 mm, and the average grain size is 100-130 μm; in step S2, the deformation of the first cold rolling is controlled at 40%-50%, and the deformation of the second cold rolling is controlled at 30%-40%; in step S3, the annealing temperature is 850-950°C, and the annealing time is 10-30 min. More preferably, the annealing temperature is 900-950°C.

[0087] c) When the initial texture type of the base material belongs to case (10), in step S1, the initial thickness t 0 The thickness of the steel sheet is 0.25-0.35 mm, and the average grain size is 130-160 μm; in step S2, the deformation of the first cold rolling is controlled at 40%-60%, and the deformation of the second cold rolling is controlled at 30%-40%; in step S3, the annealing temperature is 850-1000°C, and the annealing time is 10-30 min. More preferably, the annealing temperature is 900-950°C.

[0088] d) When the initial texture type of the base material belongs to case (11) or (12), in step S1, the initial thickness t 0 The thickness of the steel sheet is 0.30-0.35 mm, and the average grain size is 130-160 μm; in step S2, the deformation of the first cold rolling is controlled at 50%-60%, and the deformation of the second cold rolling is controlled at 30%-40%; in step S3, the annealing temperature is 850-1000°C, and the annealing time is 10-20 min. More preferably, the annealing temperature is 900-950°C.

[0089] It should be noted that for cold-rolled ultra-thin strips of different thicknesses, using the appropriate annealing temperature is beneficial to further improve the magnetic properties, mechanical properties, and product quality. In some preferred embodiments, when the final thickness of the cold-rolled ultra-thin strip is t f At 0.03mm≤t f <0.05mm, the annealing temperature is 800~1000℃; or, when the final thickness of the cold-rolled ultra-thin strip is t f At 0.05mm≤t f Under the condition of ≤0.08mm, the annealing temperature is 700-900°C.

[0090] It should be noted that in step S1, the intensity level of each of the seven texture components, as expressed by ODF (Orientation Distribution Function), is ≥ 2, which indicates that these specific texture components are dominant in the material, so that the dominant texture can be used to achieve excellent magnetic properties as well as to ensure mechanical properties and product quality.

[0091] Exemplarily, in step S3, the annealing atmosphere is a mixed gas of nitrogen and hydrogen. Preferably, the volume fraction of hydrogen in the mixed gas is V H2 ≥10%. By controlling the annealing atmosphere to contain a certain amount of hydrogen (at least 10%), the magnetic properties, mechanical properties and surface quality of ultra-thin non-oriented silicon steel strip can be further improved, while maintaining the isotropy of the material, better meeting the needs of high efficiency, high speed, high power density and lightweight.

[0092] More preferably, in the hydrogen-nitrogen mixed annealing atmosphere, the hydrogen content (i.e., volume fraction) is 10% to 40%, which can achieve a relatively ideal annealing effect while ensuring safety, easy operation, and reducing costs, thereby producing high-quality ultra-thin non-oriented silicon steel strips with excellent magnetic properties. Exemplarily, the hydrogen content (i.e., volume fraction) is 15%, 20%, 25%, 30%, and 35%.

[0093] It should be noted that in step S1, an insulating coating is provided on the surface of the base material, which can not only prevent interlayer short circuits, maintain the stability of magnetic properties, and protect the surface of the material, but also help to maintain the flatness of the material during the cold rolling process, and also help to form a more uniform temperature distribution during the annealing process, thereby improving the heat treatment effect.

[0094] It should be noted that in step S2, a multi-roll mill is used for cold rolling. During the rolling process, front and rear tensions are applied to the strip between the rollers to keep the strip flat and wrinkle-free, thereby improving the strip quality and maintaining the integrity of the insulating coating on the strip surface.

[0095] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments and comparative examples.

[0096] The present invention provides some embodiments of the ultra-thin non-oriented silicon steel strip product, namely, Embodiment 1-1 to Embodiment 12-2, see Table 1:

[0097] Table 1: Microstructure characteristics and content, overall average grain size and magnetic induction of all examples

[0098]

[0099]

[0100] The present invention also provides a preparation example of the above embodiment, see Table 2, specifically including:

[0101] (1) Preparation example of embodiment 1-1:

[0102] This preparation example provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0103] S1. A non-oriented silicon steel sheet with a thickness of 0.20 mm is selected as the base material. The average grain size of the base material is 80 μm. The initial texture type of the base material is λ-line ({001} <hk0>)+η-line({0kl} <100> ), the intensity level of the λ-line texture is 4, and the intensity level of the η-line texture is 6;

[0104] S2, cold rolling the base material at room temperature, cold rolling to 0.08 mm through 3 passes, obtaining a cold-rolled ultra-thin strip, the total deformation of cold rolling is 60%, wherein the deformation of the first cold rolling is controlled at 45%, the deformation of the second cold rolling is controlled at 25%, and finally cold rolling to 0.08 mm through one pass; during the rolling process, applying front and rear tensions to the strip between the rollers;

[0105] S3, annealing the cold-rolled ultra-thin strip at a temperature of 800°C for 30 minutes in an annealing atmosphere of 40% hydrogen + 60% nitrogen to obtain the ultra-thin non-oriented silicon steel strip product of Example 1-1, such as Figure 1 As shown in (a), the product has a flat plate shape, uniform thickness and good overall quality.

[0106] (2) Preparation example of embodiment 1-2:

[0107] The difference between this preparation example and the preparation example of Example 1-1 is that in step S1, a non-oriented silicon steel sheet with a thickness of 0.15 mm is selected as the base material, and in step S2, it is cold-rolled to 0.03 mm through 4 passes, with a total deformation of 80%; in step S3, the annealing temperature is 850°C and the annealing time is 20 min. The remaining steps and parameters are similar to those of the preparation example of Example 1-1. This preparation example obtains the ultra-thin non-oriented silicon steel strip product of Example 1-2, such as Figure 1 As shown in (b), the product has a flat plate shape, uniform thickness and good overall quality.

[0108] (3) Preparation example of embodiment 2-1:

[0109] This preparation example provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0110] S1. A non-oriented silicon steel sheet with a thickness of 0.20 mm is selected as the base material. The average grain size of the base material is 85 μm. The initial texture type of the base material is λ-line + {115} <161> Texture, the intensity level of λ-line texture is 4, {115} <161> The intensity level of the texture is 2;

[0111] S2, cold rolling the base material at room temperature, cold rolling to 0.08 mm in two passes, obtaining a cold-rolled ultra-thin strip, wherein the total deformation of the cold rolling is 60%, wherein the deformation of the first cold rolling pass is controlled at 50%, and the deformation of the second cold rolling pass is controlled at 20%; during the rolling process, applying front and rear tensions to the strip between the rollers;

[0112] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 800° C. for 20 min in an annealing atmosphere of 40% hydrogen + 60% nitrogen to obtain the ultra-thin non-oriented silicon steel strip product of Example 2-1.

[0113] (4) Preparation example of embodiment 2-2:

[0114] The difference between this preparation example and the preparation example of Example 2-1 is that: in step S1, a non-oriented silicon steel sheet with a thickness of 0.15 mm is selected as the base material, in step S2, after 5 passes of cold rolling to 0.03 mm, the total deformation is 80%, and the deformation of the first pass of cold rolling is controlled at 40%; in step S3, the annealing temperature is 850°C and the annealing time is 30 minutes. The remaining steps and parameters are similar to the preparation example of Example 2-1.

[0115] (5) Preparation example of embodiment 3-1:

[0116] This preparation example provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0117] S1. A non-oriented silicon steel sheet with a thickness of 0.20 mm is selected as the base material. The average grain size of the base material is 90 μm. The initial texture type of the base material is η-line + {115} <161> Texture, the strength level of η-line texture is 6, {115} <161> The intensity level of the texture is 2;

[0118] S2, cold rolling the base material at room temperature, cold rolling to 0.08 mm through three passes, obtaining a cold-rolled ultra-thin strip, the total deformation of the cold rolling is 60%, wherein the deformation of the first cold rolling pass is controlled at 45%, and the deformation of the second cold rolling pass is controlled at 23%; during the rolling process, applying front and rear tensions to the strip between the rollers;

[0119] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 825° C. for 25 min in an annealing atmosphere of 40% hydrogen + 60% nitrogen to obtain the ultra-thin non-oriented silicon steel strip product of Example 3-1.

[0120] (6) Preparation example of embodiment 3-2:

[0121] The difference between this preparation example and the preparation example of Example 3-1 is that in step S1, a non-oriented silicon steel sheet with a thickness of 0.15 mm is selected as the base material, and in step S2, it is cold-rolled to 0.03 mm through 4 passes, and the total deformation is 80%. The remaining steps and parameters are similar to those of the preparation example of Example 3-1.

[0122] (7) Preparation example of embodiment 4-1:

[0123] This preparation example provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0124] S1. A non-oriented silicon steel sheet with a thickness of 0.25 mm is selected as the base material. The average grain size of the base material is 100 μm, and the initial texture type of the base material is {115} <161> +γ-line texture, {115} <161> The intensity level of the texture is 2, the intensity level of the γ-ray texture is 2;

[0125] S2, cold rolling the base material at room temperature, cold rolling to 0.08 mm through three passes, obtaining a cold-rolled ultra-thin strip, wherein the total deformation of the cold rolling is 68%, wherein the deformation of the first cold rolling pass is controlled at 40%, and the deformation of the second cold rolling pass is controlled at 30%; during the rolling process, applying front and rear tensions to the strip between the rollers;

[0126] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 950° C. for 10 min in an annealing atmosphere of 30% hydrogen + 70% nitrogen to obtain the ultra-thin non-oriented silicon steel strip product of Example 4-1.

[0127] (8) Preparation example of embodiment 4-2:

[0128] The difference between this preparation example and the preparation example of Example 4-1 is that: in step S1, the average grain size of the base material is 130 μm, in step S2, after 5 passes of cold rolling to 0.03 mm, the total deformation of cold rolling is 88%, wherein the deformation of the first pass of cold rolling is controlled at 50%, and the deformation of the second pass of cold rolling is controlled at 40%; in step S3, the annealing temperature is 900°C, and the annealing time is 30 min. The remaining steps and parameters are similar to the preparation example of Example 4-1.

[0129] (9) Preparation example of embodiment 5-1:

[0130] This preparation example provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0131] S1. A non-oriented silicon steel sheet with a thickness of 0.20 mm is selected as a base material, the average grain size of the base material is 95 μm, the initial texture type of the base material is Goss+Cube texture, the strength level of the Goss texture is 4, and the strength level of the Cube texture is 4;

[0132] S2, cold rolling the base material at room temperature, cold rolling to 0.08 mm through three passes, obtaining a cold-rolled ultra-thin strip, wherein the total deformation of the cold rolling is 60%, wherein the deformation of the first cold rolling pass is controlled at 45%, and the deformation of the second cold rolling pass is controlled at 25%; during the rolling process, applying front and rear tensions to the strip between the rollers;

[0133] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 800° C. for 30 min in an annealing atmosphere of 20% hydrogen + 80% nitrogen. After annealing, the ultra-thin non-oriented silicon steel strip product of Example 5-1 is obtained.

[0134] (10) Preparation example of embodiment 5-2:

[0135] The difference between this preparation example and the preparation example of Example 5-1 is that: in step S1, a non-oriented silicon steel sheet with a thickness of 0.15 mm is selected as the base material, in step S2, it is cold-rolled to 0.03 mm through 3 passes, and the total deformation of the cold rolling is 80%, wherein the deformation of the first cold rolling pass is controlled at 50%; in step S3, the annealing temperature is 850°C, and the annealing time is 20 min. The remaining steps and parameters are similar to those of the preparation example of Example 5-1.

[0136] (11) Preparation example of Example 6-1:

[0137] This preparation example provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0138] S1. A non-oriented silicon steel sheet with a thickness of 0.20 mm is selected as the base material. The average grain size of the base material is 80 μm, and the initial texture type of the base material is {115} <161> + Goss texture, {115} <161> The intensity level of the texture is 2, and the intensity level of the Goss texture is 4;

[0139] S2, cold rolling the base material at room temperature, cold rolling to 0.08 mm through three passes, obtaining a cold-rolled ultra-thin strip, wherein the total deformation of the cold rolling is 60%, wherein the deformation of the first cold rolling pass is controlled at 40%, and the deformation of the second cold rolling pass is controlled at 20%; during the rolling process, applying front and rear tensions to the strip between the rollers;

[0140] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 850° C. for 20 min in an annealing atmosphere of 40% hydrogen + 60% nitrogen to obtain the ultra-thin non-oriented silicon steel strip product of Example 6-1.

[0141] (12) Preparation example of Example 6-2:

[0142] The difference between this preparation example and the preparation example of Example 6-1 is that: in step S1, the average grain size of the base material is 100 μm, in step S2, after 4 cold rollings to 0.03 mm, the total deformation is 85%, wherein the deformation of the first cold rolling is controlled at 50%, and the deformation of the second cold rolling is controlled at 25%; in step S3, the annealing temperature is 800°C, and the annealing time is 30 min. The remaining steps and parameters are similar to the preparation example of Example 6-1.

[0143] (13) Preparation example of Example 7-1:

[0144] This preparation example provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0145] S1. A non-oriented silicon steel sheet with a thickness of 0.30 mm is selected as a base material, the average grain size of the base material is 110 μm, the initial texture type of the base material is λ-line + η-line + γ-line texture, the strength level of the λ-line texture is 4, the strength level of the η-line texture is 5, and the strength level of the γ-line texture is 2;

[0146] S2, cold rolling the base material at room temperature, cold rolling to 0.08 mm through three passes, obtaining a cold-rolled ultra-thin strip, the total deformation of the cold rolling is 73%, wherein the deformation of the first cold rolling pass is controlled at 45%, and the deformation of the second cold rolling pass is controlled at 35%; during the rolling process, applying front and rear tensions to the strip between the rollers;

[0147] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 925° C. for 20 min in an annealing atmosphere of 40% hydrogen + 60% nitrogen to obtain the ultra-thin non-oriented silicon steel strip product of Example 7-1.

[0148] (14) Preparation example of Example 7-2:

[0149] The difference between this preparation example and the preparation example of Example 7-1 is that: in step S1, the average grain size of the base material is 120 μm, in step S2, after 4 passes of cold rolling to 0.03 mm, the total deformation is 90%, wherein the deformation of the first pass of cold rolling is controlled at 50%; in step S3, the annealing temperature is 850°C, and the annealing atmosphere is 10% hydrogen + 90% nitrogen. The remaining steps and parameters are similar to the preparation example of Example 7-1.

[0150] (15) Preparation example of Example 8-1:

[0151] This preparation example provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0152] S1. A non-oriented silicon steel sheet with a thickness of 0.20 mm is selected as the base material. The average grain size of the base material is 100 μm. The initial texture type of the base material is λ-line + η-line + {115} <161> Texture, the intensity level of λ-line texture is 4, the intensity level of η-line texture is 6, and the intensity level of {115} <161> The intensity level of the texture is 2;

[0153] S2, cold rolling the base material at room temperature, cold rolling to 0.08 mm in two passes, obtaining a cold-rolled ultra-thin strip, wherein the total deformation of the cold rolling is 60%, wherein the deformation of the first cold rolling pass is controlled at 50%, and the deformation of the second cold rolling pass is controlled at 20%; during the rolling process, applying front and rear tensions to the strip between the rollers;

[0154] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 800° C. for 20 min in an annealing atmosphere of 40% hydrogen + 60% nitrogen. After annealing, the ultra-thin non-oriented silicon steel strip product of Example 8-1 is obtained.

[0155] (16) Preparation example of Example 8-2:

[0156] The difference between this preparation example and the preparation example of Example 8-1 is that: in step S1, a non-oriented silicon steel sheet with a thickness of 0.15 mm is selected as the base material, in step S2, it is cold-rolled to 0.03 mm through 4 passes, and the total deformation is 80%, wherein the deformation of the first cold rolling pass is controlled at 40%; in step S3, the annealing temperature is 850°C, and the annealing time is 30 min. The remaining steps and parameters are similar to those of the preparation example of Example 8-1.

[0157] (17) Preparation example of Example 9-1:

[0158] This preparation example provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0159] S1. A non-oriented silicon steel sheet with a thickness of 0.20 mm is selected as the base material. The average grain size of the base material is 90 μm. The initial texture type of the base material is Goss+Cube+{115} <161> Texture, Goss texture strength level is 4, Cube texture strength level is 4, {115} <161> The intensity level of the texture is 2;

[0160] S2, cold rolling the base material at room temperature, cold rolling to 0.08 mm through 4 passes, obtaining a cold-rolled ultra-thin strip, the total deformation of cold rolling is 60%, wherein the deformation of the first cold rolling pass is controlled at 45%, and the deformation of the second cold rolling pass is controlled at 25%; during the rolling process, applying front and rear tensions to the strip between the rollers;

[0161] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 800° C. for 20 min in an annealing atmosphere of 40% hydrogen + 60% nitrogen. After annealing, the ultra-thin non-oriented silicon steel strip product of Example 9-1 is obtained.

[0162] (18) Preparation example of Example 9-2:

[0163] The difference between this preparation example and the preparation example of Example 9-1 is that: in step S1, a non-oriented silicon steel sheet with a thickness of 0.15 mm is selected as the base material; in step S2, it is cold-rolled to 0.03 mm through 4 passes, and the total deformation is 80%, wherein the deformation of the first cold rolling pass is controlled at 40%, and the deformation of the second cold rolling pass is controlled at 20%; in step S3, the annealing temperature is 850°C, and the annealing time is 30 minutes. The remaining steps and parameters are similar to those of the preparation example of Example 9-1. This preparation example obtains the ultra-thin non-oriented silicon steel strip product of Example 9-2, such as Figure 1 As shown in (c), the product has a flat plate shape, uniform thickness and good overall quality.

[0164] (19) Preparation example of Example 9-3:

[0165] The difference between this preparation example and the preparation example of Example 9-1 is that in step S1, the average grain size of the base material is 50 μm; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0166] (20) Preparation example of Example 9-4:

[0167] The difference between this preparation example and the preparation example of Example 9-1 is that in step S1, the average grain size of the base material is 180 μm; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0168] (21) Preparation example of Example 9-5:

[0169] The difference between this preparation example and the preparation example of Example 9-1 is that in step S2, the deformation amount of the first cold rolling is controlled at 30%; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0170] (22) Preparation example of Example 9-6:

[0171] The difference between this preparation example and the preparation example of Example 9-1 is that in step S1, a non-oriented silicon steel sheet with a thickness of 0.35 mm is selected as the base material; in step S2, the total deformation amount is 77%, and the deformation amount of the first cold rolling is controlled at 60%; the remaining steps and parameters are similar to the preparation example of Example 9-1.

[0172] (23) Preparation example of Example 9-7:

[0173] The difference between this preparation example and the preparation example of Example 9-1 is that in step S1, a non-oriented silicon steel sheet with a thickness of 0.35 mm is selected as the base material; in step S2, the total deformation amount is 77%, and the second cold rolling deformation amount is controlled at 40%; the remaining steps and parameters are similar to the preparation example of Example 9-1.

[0174] (24) Preparation example of embodiment 9-8:

[0175] The difference between this preparation example and the preparation example of Example 9-1 is that in step S3, the annealing temperature is 950° C.; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0176] (25) Preparation example of Example 9-9:

[0177] The difference between this preparation example and the preparation example of Example 9-1 is that in step S3, the annealing time is 60 minutes; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0178] (26) Preparation examples of Examples 9-10:

[0179] The difference between this preparation example and the preparation example of Example 9-1 is that in step S3, the annealing time is 10 minutes; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0180] (27) Preparation example of Example 10-1:

[0181] This preparation example provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0182] S1. A non-oriented silicon steel sheet with a thickness of 0.35 mm is selected as the base material. The average grain size of the base material is 130 μm. The initial texture type of the base material is Goss+Cube+{115} <161> +γ-line texture, Goss texture with an intensity level of 4, Cube texture with an intensity level of 4, {115} <161> The intensity level of the texture is 2, and the intensity level of the γ-ray texture is 2;

[0183] S2, cold rolling the base material at room temperature, cold rolling to 0.08 mm through three passes, obtaining a cold-rolled ultra-thin strip, the total deformation of the cold rolling is 77%, wherein the deformation of the first cold rolling pass is controlled at 60%, and the deformation of the second cold rolling pass is controlled at 40%; during the rolling process, applying front and rear tensions to the strip between the rollers;

[0184] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 900° C. for 30 min in an annealing atmosphere of 40% hydrogen + 60% nitrogen. After annealing, the ultra-thin non-oriented silicon steel strip product of Example 10-1 is obtained.

[0185] (28) Preparation example of Example 10-2:

[0186] The difference between this preparation example and the preparation example of Example 10-1 is that: in step S1, a non-oriented silicon steel sheet with a thickness of 0.25 mm is selected as the base material, and the average grain size of the base material is 160 μm; in step S2, after 4 cold rollings to 0.03 mm, the total deformation is 88%, wherein the deformation of the first cold rolling is controlled at 40%, and the deformation of the second cold rolling is controlled at 30%; in step S3, the annealing temperature is 950°C, and the annealing time is 10 min. The remaining steps and parameters are similar to those of the preparation example of Example 10-1.

[0187] (29) Preparation example of Example 11-1:

[0188] This preparation example provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0189] S1. A non-oriented silicon steel sheet with a thickness of 0.35 mm is selected as the base material. The average grain size of the base material is 130 μm. The initial texture type of the base material is λ-line + {115} <161> +{114} <481> +γ-line texture, the intensity level of λ-line texture is 4, {115} <161> The texture strength level is 2, {114} <481> The intensity level of the texture is 4, and the intensity level of the γ-ray texture is 4;

[0190] S2, cold rolling the base material at room temperature, cold rolling to 0.08 mm through three passes, obtaining a cold-rolled ultra-thin strip, the total deformation of the cold rolling is 77%, wherein the deformation of the first cold rolling pass is controlled at 60%, and the deformation of the second cold rolling pass is controlled at 40%; during the rolling process, applying front and rear tensions to the strip between the rollers;

[0191] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 900° C. for 20 min in an annealing atmosphere of 40% hydrogen + 60% nitrogen. After annealing, the ultra-thin non-oriented silicon steel strip product of Example 11-1 is obtained.

[0192] (30) Preparation example of Example 11-2:

[0193] The difference between this preparation example and the preparation example of Example 11-1 is that: in step S1, the average grain size of the base material is 160 μm, in step S2, after 5 passes of cold rolling to 0.03 mm, the total deformation is 92%, wherein the deformation of the first pass of cold rolling is controlled at 50%, and the deformation of the second pass of cold rolling is controlled at 30%; in step S3, the annealing temperature is 1000° C., and the annealing atmosphere is 10% hydrogen + 90% nitrogen. The remaining steps and parameters are similar to the preparation example of Example 11-1.

[0194] (31) Preparation example of Example 12-1:

[0195] This preparation example provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0196] S1. A non-oriented silicon steel sheet with a thickness of 0.30 mm is selected as the base material. The average grain size of the base material is 140 μm. The initial texture type of the base material is λ-line + {114} <481> +γ-line texture, the intensity level of λ-line texture is 4, {114} <481> The intensity level of the texture is 2, and the intensity level of the γ-ray texture is 4;

[0197] S2, cold rolling the base material at room temperature, cold rolling to 0.08 mm through three passes, obtaining a cold-rolled ultra-thin strip, the total deformation of the cold rolling is 73%, wherein the deformation of the first cold rolling pass is controlled at 55%, and the deformation of the second cold rolling pass is controlled at 35%; during the rolling process, applying front and rear tensions to the strip between the rollers;

[0198] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 950° C. for 15 min in an annealing atmosphere of 40% hydrogen + 60% nitrogen to obtain the ultra-thin non-oriented silicon steel strip product of Example 12-1.

[0199] (32) Preparation example of Example 12-2:

[0200] The difference between this preparation example and the preparation example of Example 12-1 is that in step S1, the average grain size of the base material is 150 μm, in step S2, it is cold rolled to 0.03 mm after 5 passes, and the total deformation is 90%, and in step S3, the annealing temperature is 850°C; the remaining steps and parameters are similar to those of the preparation example of Example 12-1.

[0201] Comparative Example 1:

[0202] The difference between this comparative example and the preparation example of Example 9-1 is that in step S1, the average grain size of the base material is 40 μm; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0203] Comparative Example 2:

[0204] The difference between this comparative example and the preparation example of Example 9-1 is that in step S1, the average grain size of the base material is 200 μm; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0205] Comparative Example 3:

[0206] The difference between this comparative example and the preparation example of Example 9-1 is that in step S2, the deformation amount of the first cold rolling is controlled at 25%; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0207] Comparative Example 4:

[0208] The difference between this comparative example and the preparation example of Example 9-1 is that in step S1, the base material thickness t 0 =0.35mm; in step S2, the deformation of the first cold rolling is controlled at 65%; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0209] Comparative Example 5:

[0210] The difference between this comparative example and the preparation example of Example 9-1 is that in step S2, the deformation amount of the second cold rolling is controlled at 15%; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0211] Comparative Example 6:

[0212] The difference between this comparative example and the preparation example of Example 9-1 is that in step S2, the deformation amount of the second cold rolling is controlled at 45%; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0213] Comparative Example 7:

[0214] The difference between this comparative example and the preparation example of Example 9-1 is that in step S3, the annealing temperature is 650° C.; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0215] Comparative Example 8:

[0216] The difference between this comparative example and the preparation example of Example 9-1 is that in step S3, the annealing temperature is 1050°C; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0217] Comparative Example 9:

[0218] The difference between this comparative example and the preparation example of Example 9-1 is that in step S3, the annealing time is 8 minutes; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0219] Comparative Example 10:

[0220] The difference between this comparative example and the preparation example of Example 9-1 is that in step S3, the annealing time is 65 minutes; the remaining steps and parameters are similar to those of the preparation example of Example 9-1.

[0221] In order to more clearly show the parameter variables and performance test results of the preparation examples of all the above embodiments and all the comparative examples, see Table 2 and Table 3. As can be seen from Table 2, the corresponding preparation examples of the above embodiments adopt the preparation method provided by the present invention to obtain ultra-thin non-oriented silicon steel strip products with high magnetic induction and low medium and high frequency iron loss, and the magnetic induction intensity B 5000 All can reach 1.66T and above, most B 5000 Can reach above 1.70, medium frequency iron loss P 1.0 / 400 Can be controlled below 10.8W / kg, most P 1.0 / 400 Can be controlled below 10.0W / kg, high frequency iron loss P 1.0 / 1000 It can be controlled below 22.7W / kg (since 0.08mm strips are more often used in the medium frequency field, the key parameters P are listed in Table 2. 1.0 / 400 ). Compared with the preparation examples of Examples 9-3 to 9-10, the magnetic properties of the strip product obtained in the preparation example of Example 9-1 are better due to the use of more preferred base materials and process parameters (such as the thickness of the base material, the average grain size, the ratio of the deformation amount of the first pass and the second pass in rolling, the annealing temperature and time).

[0222] As can be seen from Table 3, since Comparative Examples 1-10 do not adopt the appropriate range of the base material and process parameters in the preparation method provided by the present invention, the overall magnetic properties of Comparative Examples 1-10 are not as good as those of the preparation examples listed in Table 2. For example, B 5000 Decline, P 1.0 / 400 The processing performance and quality of the obtained strip are also not as good as the products obtained in the preparation examples listed in Table 2 (i.e., the strip products in the corresponding embodiments).

[0223] In addition, the products obtained from all the preparation examples in Table 2, i.e., the strip products in the corresponding embodiments, have good overall quality, flat plate shape, no defects, and excellent mechanical properties. For example, the yield strength of the 0.08 mm strip product is greater than 450 MPa, and the tensile strength is greater than 500 MPa; the yield strength of the 0.03 mm strip product is greater than 350 MPa, and the tensile strength is greater than 400 MPa.

[0224] Table 2: Base materials, main process parameters and performance results of all preparation examples

[0225]

[0226]

[0227]

[0228] Table 3: Base materials, main process parameters and performance results of all comparative examples

[0229]

[0230] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. An ultra-thin non-oriented silicon steel strip, characterized in that: The thickness of the strip is t f ≤0.10 mm, the texture type of the strip includes a relatively high content of λ-lines ({001} <hk0>), η-line ({0kl} <100> ), <115> / / NDThese three textures, as well as the lower content of γ-rays (ND / / <111> )Texture;< / hk0> Among them, the λ-line ({001} <hk0> ) texture content is 10.8% to 25.8%, η-line ({0kl} <100> ) Texture content is 13.2% to 50.5%, <115> / / ND texture content is 31.4% to 52.8%; γ-ray (ND / / <111> )Texture content is 12.9% to 19.9%.< / hk0> 2. The ultra-thin non-oriented silicon steel strip according to claim 1, characterized in that: The number of grain layers of the side structure of the strip is 1-2 layers, and the grain structure of the strip is equiaxed grains.

3. The ultra-thin non-oriented silicon steel strip according to claim 1, characterized in that: The total average grain size of the strip is 27 μm to 74 μm; wherein the λ-line ({001} <hk0> ), η-line ({0kl} <100> ), <115> / / ND The average grain size of any of the three textures is ≥ the total average grain size. The γ-line (ND / / <111> )The average grain size of the texture is ≤ the overall average grain size.< / hk0> 4. The ultra-thin non-oriented silicon steel strip according to claim 1, characterized in that: The λ-line ({001} <hk0> ) texture includes Cube({001} <100> )、{001} <110> 、{001} <120> The three orientation components; and / or,< / hk0> The n-line ({0k1} <100> ) textures include Goss ({011} <100> ), {210} <001> These two orientation components.

5. The ultra-thin non-oriented silicon steel strip according to claim 1, characterized in that: The thickness of the strip is t f 0.03mm~0.08mm; when 0.03mm≤t f <0.05mm, the yield strength R of the strip e ≥350MPa, tensile strength R m ≥400Mpa; when 0.05mm≤t f ≤0.08mm, the yield strength of the strip R e ≥450MPa, tensile strength R m ≥500Mpa.

6. The ultra-thin non-oriented silicon steel strip according to claim 1, characterized in that: The magnetic properties of the strip in each direction can reach: magnetic induction intensity B 5000 ≥1.66T, iron loss P 1.0 / 400 <10.8W / kg,P 1.0 / 1000 <22.7W / kg.

7. The ultra-thin non-oriented silicon steel strip according to claim 1, characterized in that: The λ-line ({001} <hk0> ) texture content is 15.0% to 25.8%, η-line ({0kl} <100> ) Texture content is 32.1% to 50.5%, <115> / / ND texture content is 39.9% to 51.4%; γ-ray (ND / / <111> ) Texture content is 12.9% to 18.4%;< / hk0> The magnetic induction intensity B of the strip in each direction 5000 ≥1.73T.

8. The ultra-thin non-oriented silicon steel strip according to claim 1, characterized in that: The strip includes: small-angle grain boundaries of 2°≤α≤15° with a grain boundary ratio of 19.5% to 34.7%, and large-angle grain boundaries of α>45° with a grain boundary ratio of 18.9% to 33.4%. α is the orientation difference between adjacent grains.

9. The method for preparing an ultra-thin non-oriented silicon steel strip according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Selecting a non-oriented silicon steel sheet with an initial thickness t0 of 0.15-0.35 mm as a base material, wherein the average grain size of the base material is 50-180 μm; S2, cold rolling the base material at room temperature to obtain a final thickness t through multiple cold rolling passes. f Cold-rolled ultra-thin strip ≤0.1mm; S3, annealing the cold-rolled ultra-thin strip.

10. The preparation method according to claim 9, characterized in that: In step S2, the strength level of the cold-rolled ultra-thin strip on the ODF cross-sectional view at φ2=45° is: λ-line ({001} <hk0> ) texture ≥ α* line texture > γ-line (ND / / <111> ) texture, and the λ-line texture contains strong Cube ({001} <100> ) texture, the strength level of Cube texture is ≥2.< / hk0>

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