Preparation method of ultrathin non-oriented silicon steel strip

Abstract

The invention relates to a preparation method of an ultrathin non-oriented silicon steel strip, belongs to the technical field of non-oriented silicon steel, and solves at least one of the following problems in an existing preparation method and a product of the non-oriented silicon steel strip: the magnetic performance is difficult to reach a high standard, and the product quality is difficult to guarantee while the thickness is reduced; and the preparation process flow is relatively tedious. The preparation method comprises the following steps: S1, selecting a non-oriented silicon steel plate with the initial thickness of 0.15-0.35 mm as a base material; s2, the base metal is subjected to cold rolling at the room temperature, and a cold-rolled ultrathin strip with the final thickness ranging from 0.03 mm to 0.08 mm is obtained through multi-pass cold rolling; and S3, the cold-rolled ultrathin strip is annealed. The preparation method is easy to operate and short in technological process, and the obtained strip product is high in magnetic induction, low in iron loss, very thin in thickness and good in surface quality and mechanical property.

Description

Technical Field

[0001] The invention relates to the technical field of non-oriented silicon steel, and in particular to a method for preparing an ultra-thin non-oriented silicon steel strip. 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 bottlenecks and problems of the existing preparation methods mainly include: the magnetic properties are difficult to reach high standards, such as high magnetic induction (i.e., magnetic induction B 5000 >1.6T) and low iron loss (i.e., 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 a method for preparing ultra-thin non-oriented silicon steel strip, so as to solve at least one of the following problems existing in the existing methods for preparing non-oriented silicon steel strip and its products: (1) It is difficult to achieve high magnetic properties, such as high magnetic induction (i.e., magnetic induction B 5000 >1.60T) and low iron loss (i.e., P 1.0 / 400 <11W / kg、P 1.0 / 1000 <35W / kg); (2) It is difficult to reduce the thickness (0.03~0.08mm) 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 a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0007] S1. A non-oriented silicon steel sheet with an initial thickness t0 of 0.15 to 0.35 mm is selected as the base material. The average grain size of the base material is 50 to 180 μm. 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;

[0008] S2, cold rolling the base material at room temperature, the total deformation of cold rolling is 46% to 92%, wherein the deformation of the first cold rolling is controlled at 30% to 60%, the deformation of the second cold rolling is controlled at 20% to 40%, and the final thickness t is obtained by multiple cold rolling. f It is a cold-rolled ultra-thin strip of 0.03-0.08 mm;

[0009] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 700 to 1000° C. for a time of 10 to 60 minutes in an annealing atmosphere of hydrogen or a mixture of hydrogen and nitrogen.

[0010] Furthermore, the grain structure of the selected parent material is equiaxed.

[0011] Furthermore, the number of grain layers of the side structure of the base material is 1-3 layers, and at least 25% of the grains penetrate the thickness of the base material.

[0012] Furthermore, the initial texture type of the base material belongs to at least one of the following 12 situations: (1) λ-line + η-line texture; (2) λ-line + {115} <161> Texture; (3) η-line + {115} <161> Texture; (4) {115} <161> +γ-line texture; (5) Goss+Cube texture; (6) {115} <161> + Goss texture; (7) λ-line + η-line + γ-line texture; (8) λ-line + η-line + {115} <161> Texture; (9) Goss+Cube+{115} <161> Texture; (10) Goss+Cube+{115} <161> +γ-line texture; (11)λ-line +{115} <161> +{114} <481> +γ-line texture; (12)λ-line +{114} <481> +γ-line texture.

[0013] Furthermore, when the initial texture type of the base material belongs to at least one of the seven cases (1), (2), (3), (5), (6), (8), and (9), in step S1, the initial thickness t0 is 0.15 to 0.20 mm, and the average grain size is 80 to 100 μm; in step S2, the deformation amount of the first cold rolling is controlled at 40% to 50%, and the deformation amount of the second cold rolling is controlled at 20% to 25%; in step S3, the annealing temperature is 800 to 850°C, and the annealing time is 20 to 30 min.

[0014] Furthermore, when the initial texture type of the base material belongs to case (4) or (7), in step S1, the initial thickness t0 is 0.25-0.30 mm, and the average grain size is 100-130 μm; in step S2, the deformation amount of the first cold rolling is controlled at 40%-50%, and the deformation amount 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.

[0015] Furthermore, when the initial texture type of the base material belongs to case (10), in step S1, the initial thickness t0 is 0.25-0.35 mm, and the average grain size is 130-160 μm; in step S2, the deformation amount of the first cold rolling is controlled at 40%-60%, and the deformation amount 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.

[0016] Furthermore, when the initial texture type of the base material belongs to case (11) or (12), in step S1, the initial thickness t0 is 0.30-0.35 mm, and the average grain size is 130-160 μm; in step S2, the deformation amount of the first cold rolling is controlled at 50%-60%, and the deformation amount 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.

[0017] Furthermore, 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℃.

[0018] Further, in step S1, the texture strength level of each of the seven texture components is ≥ 2; and / or,

[0019] In step S3, the annealing atmosphere is a mixed gas of nitrogen and hydrogen, wherein the volume fraction of hydrogen in the mixed gas is V H2 ≥10%.

[0020] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0021] (1) The ultra-thin non-oriented silicon steel strip obtained by the preparation method provided by the present invention has high magnetic induction and low medium and high frequency iron loss, for example: 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.

[0022] (2) The preparation method provided by the present invention can obtain a strip product with a thickness of t f Very thin while ensuring good surface quality and excellent mechanical properties. For example, 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.

[0023] (3) 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.

[0024] (4) In the present invention, a suitable base material is selected from the perspective of texture, and an ultra-thin non-oriented silicon steel strip with excellent medium and high frequency magnetic properties is prepared through a suitable rolling process and an annealing process. Specifically, a non-oriented silicon steel plate with a characteristic initial structure is used as the base material, and the total deformation amount of the cold rolling process, the first cold rolling deformation amount, and the second cold rolling deformation amount are reasonably proportioned by controlling the ratio, and the appropriate annealing temperature and time and annealing atmosphere are selected, wherein each process of base material selection, cold rolling, and annealing is based on the previous process, and the process parameters are adapted to the base material, thereby solving at least one of the above-mentioned bottlenecks and problems existing in the existing preparation method. The strip product obtained by the preparation method of the present invention can meet the high standard magnetic property requirements, and can ensure the surface quality and mechanical properties of the product while being very thin.

[0025] (5) In some preferred embodiments, by selecting a base material with the following microscopic grain structure, for example, equiaxed grains, the side structure of the base material has 1-3 layers of grains, and at least 25% of the grains penetrate the thickness of the base material, it helps to further improve the magnetic induction and reduce the iron loss, improve the mechanical properties, and improve the isotropy and structural uniformity.

[0026] (6) In some preferred embodiments, selecting 12 base materials with characteristic initial structures from different combinations of 7 textures is beneficial to further improve magnetic properties, improve mechanical properties, and have better structural uniformity and surface quality. Based on these 12 characteristic initial structures, by selecting base materials with appropriate thickness and average grain size, and after carefully designed cold rolling and annealing processes, they can be transformed into high-quality ultra-thin non-oriented silicon steel strips with better magnetic properties.

[0027] (7) In some preferred embodiments, according to the different thickness ranges of the cold-rolled ultra-thin strip obtained by cold rolling, a more preferred annealing temperature is selected, and / or a certain amount (at least 10%) of hydrogen is controlled in the annealing atmosphere, which can further improve the magnetic properties, mechanical properties and surface quality of the ultra-thin non-oriented silicon steel strip, while maintaining the isotropy of the material, thereby better meeting the requirements of high efficiency, high speed, high power density and light weight.

[0028] 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

[0029] The drawings are only for the purpose of illustrating specific embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0030] Figure 1 A flow chart of the preparation method provided by the present invention;

[0031] Figure 2 These are actual photos of ultra-thin non-oriented silicon steel strip products prepared according to the embodiments of the present invention, (a) is Embodiment 1-1, (b) is Embodiment 1-2; and (c) is Embodiment 9-2. DETAILED DESCRIPTION

[0032] 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.

[0033] In the production process of ultra-thin non-oriented silicon steel, the selection of parent material, rolling process and annealing process are three key links, which have an impact on the magnetic properties, quality and mechanical properties of the final product. The existing preparation methods usually focus on the parameter adjustment of the process itself. The production process of ultra-thin non-oriented silicon steel strips encounters the following bottlenecks: it is difficult to meet the high-standard magnetic performance requirements, it is difficult to achieve a very thin thickness (0.03-0.08mm) while ensuring product quality, and the preparation process is relatively cumbersome. The inventors of the present invention found in their research that the micro-texture type of the parent material has a significant impact on the magnetic properties, but the existing technology rarely considers how to obtain high-quality ultra-thin non-oriented silicon steel strips with excellent magnetic properties from the perspective of micro-texture screening.

[0034] Based on this, on the one hand, the present invention provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0035] S1. A non-oriented silicon steel sheet with an initial thickness t0 of 0.15 to 0.35 mm is selected as the base material. The average grain size of the base material is 50 to 180 μm. 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;

[0036] S2, cold rolling the base material at room temperature, the total deformation of cold rolling is 46% to 92%, wherein the deformation of the first cold rolling is controlled at 30% to 60%, the deformation of the second cold rolling is controlled at 20% to 40%, and the final thickness t is obtained by multiple cold rolling. f It is a cold-rolled ultra-thin strip of 0.03-0.08 mm;

[0037] S3. Annealing the cold-rolled ultra-thin strip at a temperature of 700 to 1000° C. for a time of 10 to 60 minutes in an annealing atmosphere of hydrogen or a mixture of hydrogen and nitrogen.

[0038] 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.

[0039] The ultra-thin non-oriented silicon steel strip obtained by the preparation method 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.

[0040] The preparation method provided by the present invention can ensure that the surface quality of the prepared strip product is good and the mechanical properties are excellent while the thickness is very thin. For example, 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.

[0041] In the present invention, suitable base materials are selected from the perspective of texture, and ultra-thin non-oriented silicon steel strips with excellent medium and high frequency magnetic properties are prepared through suitable rolling and annealing processes; specifically, non-oriented silicon steel plates with characteristic initial structures are used as base materials, and 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 is controlled, and suitable annealing temperature and time and annealing atmosphere are selected, wherein each process of base material selection, cold rolling and annealing is based on the previous process, and the process parameters are adapted to the base material, thereby solving at least one of the above-mentioned bottlenecks and problems existing in the existing preparation methods. The strip products obtained by the preparation method of the present invention can meet the high-standard magnetic property requirements, and can ensure the surface quality and good mechanical properties of the products while being very thin.

[0042] 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.

[0043] 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.

[0044] 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%.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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%.

[0050] 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.

[0051] In some preferred embodiments, the initial texture type of the parent material belongs to at least one of the following 12 situations:

[0052] (1)λ-line +η-line texture;

[0053] (2)λ-line+{115} <161> Texture;

[0054] (3) η-line + {115} <161> Texture;

[0055] (4){115} <161> +γ-line texture;

[0056] (5) Goss+Cube texture;

[0057] (6){115} <161> +Goss texture;

[0058] (7)λ-line +η-line +γ-line texture;

[0059] (8)λ-line+η-line+{115} <161> Texture;

[0060] (9) Goss+Cube+{115} <161> Texture;

[0061] (10) Goss+Cube+{115} <161> +γ-line texture;

[0062] (11)λ-line+{115} <161> +{114} <481> +γ-line texture;

[0063] (12)λ-line+{114} <481> +γ-line texture.

[0064] 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.

[0065] 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:

[0066] a) When the initial texture type of the base material belongs to at least one of the seven cases (1), (2), (3), (5), (6), (8) and (9), in step S1, the initial thickness t0 is 0.15-0.20 mm, and the average grain size is 80-100 μm; in step S2, the deformation amount of the first cold rolling is controlled at 40%-50%, and the deformation amount 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.

[0067] b) When the initial texture type of the base material belongs to case (4) or (7), in step S1, the initial thickness t0 is 0.25-0.30 mm, and the average grain size is 100-130 μm; in step S2, the first cold rolling deformation is controlled at 40%-50%, and the second cold rolling deformation 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.

[0068] c) When the initial texture type of the base material belongs to case (10), in step S1, the initial thickness t0 is 0.25-0.35 mm, and the average grain size is 130-160 μm; in step S2, the first cold rolling deformation is controlled at 40%-60%, and the second cold rolling deformation 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.

[0069] d) When the initial texture type of the base material belongs to case (11) or (12), in step S1, the initial thickness t0 is 0.30-0.35 mm, and the average grain size is 130-160 μm; in step S2, the first cold rolling deformation is controlled at 50%-60%, and the second cold rolling deformation 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.

[0070] 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.

[0071] 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.

[0072] Preferably, in step S2, the strength level of the cold-rolled ultra-thin strip on the ODF cross-sectional view at φ2=45° is: <hk0>) texture ≥ α* line texture > γ-line (ND / / <111> ) texture, and the λ-line texture contains strong Cube ({001} <100> ) texture, Cube texture strength level ≥ 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.

[0073] 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.

[0074] 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%.

[0075] 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.

[0076] 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.

[0077] On the other hand, the present invention also provides an ultra-thin non-oriented silicon steel strip obtained by the preparation method as described above, wherein the thickness of the strip is t f 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;

[0078] 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%.

[0079] Compared with the prior art, the ultra-thin non-oriented silicon steel strip prepared by the preparation method 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.

[0080] 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.

[0081] In some preferred embodiments, 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.

[0082] Furthermore, when the strip is very thin (0.03-0.08 mm), 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.

[0083] In some preferred embodiments, the strip includes: a small-angle grain boundary of 2°≤α≤15° with a grain boundary ratio of 19.5% to 34.7%, and a large-angle grain boundary 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 R of the strip 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.

[0084] 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 grains and 1-2 layers of grains help to increase the consistency of the arrangement of magnetic domains inside the material, thereby improving the 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 movement, thereby optimizing the high-frequency characteristics of the strip.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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%.

[0089] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments and comparative examples.

[0090] (1) Example 1-1:

[0091] This embodiment provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0092] 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 λ-line texture intensity level is 4, and the η-line texture intensity level is 6;

[0093] 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;

[0094] S3, annealing the cold-rolled ultra-thin strip, annealing temperature 800 ° C, annealing time 30min, annealing atmosphere 40% hydrogen + 60% nitrogen, after annealing to obtain ultra-thin non-oriented silicon steel strip products, such as Figure 2 As shown in (a), the product has a flat plate shape, uniform thickness and good overall quality.

[0095] (2) Embodiment 1-2:

[0096] The difference between this embodiment and embodiment 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; in step S2, it is cold-rolled to 0.03 mm through 4 passes, and the total deformation is 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 embodiment 1-1. The ultra-thin non-oriented silicon steel strip product obtained in this embodiment is as follows: Figure 2 As shown in (b), the product has a flat plate shape, uniform thickness and good overall quality.

[0097] (3) Example 2-1:

[0098] This embodiment provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0099] 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;

[0100] 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;

[0101] 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 an ultra-thin non-oriented silicon steel strip product.

[0102] (4) Example 2-2:

[0103] The difference between this embodiment and embodiment 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 those of embodiment 2-1.

[0104] (5) Example 3-1:

[0105] This embodiment provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0106] 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;

[0107] 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;

[0108] 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 an ultra-thin non-oriented silicon steel strip product.

[0109] (6) Example 3-2:

[0110] The difference between this embodiment and embodiment 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 embodiment 3-1.

[0111] (7) Example 4-1:

[0112] This embodiment provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0113] 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;

[0114] 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;

[0115] 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 an ultra-thin non-oriented silicon steel strip product.

[0116] (8) Example 4-2:

[0117] The difference between this embodiment and embodiment 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 those of embodiment 4-1.

[0118] (9) Example 5-1:

[0119] This embodiment provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0120] 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;

[0121] 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;

[0122] 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 to obtain an ultra-thin non-oriented silicon steel strip product.

[0123] (10) Example 5-2:

[0124] The difference between this embodiment and embodiment 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 embodiment 5-1.

[0125] (11) Example 6-1:

[0126] This embodiment provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0127] 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 ODF intensity level of the texture is 2, and the ODF intensity level of the Goss texture is 4;

[0128] 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;

[0129] 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 an ultra-thin non-oriented silicon steel strip product.

[0130] (12) Example 6-2:

[0131] The difference between this embodiment and embodiment 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 those of embodiment 6-1.

[0132] (13) Example 7-1:

[0133] This embodiment provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0134] 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;

[0135] 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;

[0136] 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 an ultra-thin non-oriented silicon steel strip product.

[0137] (14) Example 7-2:

[0138] The difference between this embodiment and embodiment 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 those of embodiment 7-1.

[0139] (15) Example 8-1:

[0140] This embodiment provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0141] 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;

[0142] 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;

[0143] 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 an ultra-thin non-oriented silicon steel strip product.

[0144] (16) Example 8-2:

[0145] The difference between this embodiment and embodiment 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 embodiment 8-1.

[0146] (17) Example 9-1:

[0147] This embodiment provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0148] 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;

[0149] 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;

[0150] 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 an ultra-thin non-oriented silicon steel strip product.

[0151] (18) Example 9-2:

[0152] The difference between this embodiment and embodiment 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 embodiment 9-1. The ultra-thin non-oriented silicon steel strip product obtained in this embodiment is as follows Figure 2 As shown in (c), the product has a flat plate shape, uniform thickness and good overall quality.

[0153] (19) Example 9-3:

[0154] The difference between this embodiment and embodiment 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 embodiment 9-1.

[0155] (20) Example 9-4:

[0156] The difference between this embodiment and embodiment 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 embodiment 9-1.

[0157] (21) Example 9-5:

[0158] The difference between this embodiment and embodiment 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 embodiment 9-1.

[0159] (22) Example 9-6:

[0160] The difference between this embodiment and embodiment 9-1 is that: in step S1, a non-oriented silicon steel plate 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 those of embodiment 9-1.

[0161] (23) Example 9-7:

[0162] The difference between this embodiment and embodiment 9-1 is that: in step S1, a non-oriented silicon steel plate 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 those of embodiment 9-1.

[0163] (24) Embodiment 9-8:

[0164] The difference between this embodiment and embodiment 9-1 is that in step S3, the annealing temperature is 950°C; the remaining steps and parameters are similar to those of embodiment 9-1.

[0165] (25) Example 9-9:

[0166] The difference between this embodiment and embodiment 9-1 is that in step S3, the annealing time is 60 minutes; the remaining steps and parameters are similar to those of embodiment 9-1.

[0167] (26) Embodiments 9-10:

[0168] The difference between this embodiment and embodiment 9-1 is that in step S3, the annealing time is 10 minutes; the remaining steps and parameters are similar to those of embodiment 9-1.

[0169] (27) Example 10-1:

[0170] This embodiment provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0171] 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 intensity level 4, Cube texture with intensity level 4, {115} <161> The intensity level of the texture is 2, and the intensity level of the γ-ray texture is 2;

[0172] 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;

[0173] 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 to obtain an ultra-thin non-oriented silicon steel strip product.

[0174] (28) Example 10-2:

[0175] The difference between this embodiment and embodiment 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 embodiment 10-1.

[0176] (29) Example 11-1:

[0177] This embodiment provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0178] 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;

[0179] 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;

[0180] 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 to obtain an ultra-thin non-oriented silicon steel strip product.

[0181] (30) Example 11-2:

[0182] The difference between this embodiment and embodiment 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 those of embodiment 11-1.

[0183] (31) Example 12-1:

[0184] This embodiment provides a method for preparing an ultra-thin non-oriented silicon steel strip, comprising the following steps:

[0185] 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;

[0186] 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;

[0187] 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 an ultra-thin non-oriented silicon steel strip product.

[0188] (32) Example 12-2:

[0189] The difference between this embodiment and embodiment 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 embodiment 12-1.

[0190] Comparative Example 1:

[0191] The difference between this comparative example and 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 Example 9-1.

[0192] Comparative Example 2:

[0193] The difference between this comparative example and 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 Example 9-1.

[0194] Comparative Example 3:

[0195] The difference between this comparative example and 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 Example 9-1.

[0196] Comparative Example 4:

[0197] The difference between this comparative example and Example 9-1 is that in step S1, the base material thickness t0=0.35 mm; in step S2, the deformation amount of the first cold rolling is controlled at 65%; and the remaining steps and parameters are similar to those of Example 9-1.

[0198] Comparative Example 5:

[0199] The difference between this comparative example and 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 Example 9-1.

[0200] Comparative Example 6:

[0201] The difference between this comparative example and 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 Example 9-1.

[0202] Comparative Example 7:

[0203] The difference between this comparative example and Example 9-1 is that in step S3, the annealing temperature is 650°C; the remaining steps and parameters are similar to those of Example 9-1.

[0204] Comparative Example 8:

[0205] The difference between this comparative example and Example 9-1 is that in step S3, the annealing temperature is 1050°C; the remaining steps and parameters are similar to those of Example 9-1.

[0206] Comparative Example 9:

[0207] The difference between this comparative example and Example 9-1 is that in step S3, the annealing time is 8 minutes; the remaining steps and parameters are similar to those of Example 9-1.

[0208] Comparative Example 10:

[0209] The difference between this comparative example and Example 9-1 is that in step S3, the annealing time is 65 minutes; the remaining steps and parameters are similar to those of Example 9-1.

[0210] In order to more clearly show the parameter variables and magnetic properties test results of the above examples and comparative examples, see Table 1 and Table 2. In addition, Table 3 lists the microstructure and content, total average grain size and magnetic properties of the ultra-thin non-oriented silicon steel strips prepared in all examples.

[0211] It can be seen from Table 1 that the ultra-thin non-oriented silicon steel strip product obtained by the preparation method provided by the present invention has 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 1 1.0 / 400 ). Compared with Examples 9-3 to 9-10, Example 9-1 has better magnetic properties of the strip product obtained in Example 9-1 due to the use of more preferred parent materials and process parameters (such as the thickness of the parent material, the average grain size, the ratio of the deformation amount of the first and second passes in rolling, the annealing temperature and time). At the same time, the ultra-thin non-oriented silicon steel strip products obtained in all the above embodiments have good overall quality, flat plate shape, and no defects. The products obtained in the embodiments of the present invention have excellent mechanical properties. For example, the yield strength of the 0.08mm strip product is greater than 450MPa, and the tensile strength is greater than 500MPa; the yield strength of the 0.03mm strip product is greater than 350MPa, and the tensile strength is greater than 400MPa.

[0212] As can be seen from Table 2, 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 present invention. For example, B 5000 Decline, P 1.0 / 400 The processing performance and the quality of the obtained strip are also not as good as the product obtained in the embodiment of the present invention.

[0213] Table 1: Base materials, main process parameters and performance results of all examples

[0214]

[0215]

[0216]

[0217]

[0218] Table 2: Base materials, main process parameters and performance results of all comparative examples

[0219]

[0220]

[0221] Table 3: The strip products obtained in the examples include microstructure and content, overall average grain size and magnetic induction

[0222]

[0223]

[0224] 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. A method for preparing an ultra-thin non-oriented silicon steel strip, characterized in that: The following steps are involved: S1. A non-oriented silicon steel sheet with an initial thickness t0 of 0.15 to 0.35 mm is selected as a base material. The average grain size of the base material is 50 to 180 μm. 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; S2, cold rolling the base material at room temperature, the total deformation of the cold rolling is 46% to 92%, wherein the deformation of the first cold rolling is controlled at 30% to 60%, the deformation of the second cold rolling is controlled at 20% to 40%, and the final thickness t is obtained by multiple cold rolling. f It is a cold-rolled ultra-thin strip of 0.03-0.08 mm; S3, annealing the cold-rolled ultra-thin strip at a temperature of 700-1000° C. for a time of 10-60 min in an annealing atmosphere of hydrogen or a mixture of hydrogen and nitrogen.

2. The preparation method according to claim 1, characterized in that: The grain structure of the selected parent material is equiaxed grain.

3. The preparation method according to claim 1, characterized in that: The number of crystal grain layers of the side structure of the parent material is 1-3 layers, and at least 25% of the crystal grains penetrate the thickness of the parent material.

4. The preparation method according to claim 1, characterized in that: The initial texture type of the base material belongs to at least one of the following 12 situations: (1) λ-line + η-line texture; (2) λ-line + {115} <161> Texture; (3) η-line + {115} <161> Texture; (4) {115} <161> +γ-line texture; (5) Goss+Cube texture; (6) {115} <161> + Goss texture; (7) λ-line + η-line + γ-line texture; (8) λ-line + η-line + {115} <161> Texture; (9) Goss+Cube+{115} <161> Texture; (10) Goss+Cube+{115} <161> +γ-line texture; (11)λ-line +{115} <161> +{114} <481> +γ-line texture; (12)λ-line +{114} <481> +γ-line texture.

5. The preparation method according to claim 4, characterized in that: When the initial texture type of the base material belongs to at least one of the seven cases (1), (2), (3), (5), (6), (8), and (9), in step S1, the initial thickness t0 is 0.15 to 0.20 mm, and the average grain size is 80 to 100 μm; In step S2, the deformation amount of the first cold rolling is controlled at 40% to 50%, and the deformation amount of the second cold rolling is controlled at 20% to 25%; in step S3, the annealing temperature is 800 to 850°C, and the annealing time is 20 to 30 minutes.

6. The preparation method according to claim 4, characterized in that: When the initial texture type of the parent material belongs to case (4) or (7), in step S1, the initial thickness t0 is 0.25-0.30 mm, and the average grain size is 100-130 μm; In step S2, the deformation amount of the first cold rolling is controlled at 40% to 50%, and the deformation amount of the second cold rolling is controlled at 30% to 40%; in step S3, the annealing temperature is 850 to 950°C, and the annealing time is 10 to 30 minutes.

7. The preparation method according to claim 4, characterized in that: When the initial texture type of the base material belongs to case (10), in step S1, the initial thickness t0 is 0.25-0.35 mm, and the average grain size is 130-160 μm; in step S2, the deformation amount of the first cold rolling is controlled at 40%-60%, and the deformation amount 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.

8. The preparation method according to claim 4, characterized in that: When the initial texture type of the base material belongs to case (11) or (12), in step S1, the initial thickness t0 is 0.30-0.35 mm, and the average grain size is 130-160 μm; in step S2, the deformation amount of the first cold rolling is controlled at 50%-60%, and the deformation amount 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.

9. The preparation method according to claim 1, characterized in that: 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.

10. The preparation method according to claim 1, characterized in that: In step S1, the texture strength level of each of the seven texture components is ≥ 2; and / or, In step S3, the annealing atmosphere is a mixed gas of nitrogen and hydrogen, wherein the volume fraction of hydrogen in the mixed gas is V H2 ≥10%.

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