A primary recrystallization annealing method for 0.08mm ultra-thin oriented silicon steel strip

Abstract

This invention relates to a method for preparing ultrathin oriented silicon steel strip, comprising the following steps: selecting a 0.27mm thick, high-magnetic-induction oriented silicon steel sheet without a base layer as the initial base material, and removing its surface insulation layer and oxide layer; rolling the treated base material to 0.08mm using precision cold rolling to obtain a cold-rolled hard ultrathin oriented silicon steel strip; subjecting the obtained cold-rolled hard ultrathin oriented silicon steel strip to initial recrystallization annealing in a vacuum environment at a temperature of 900℃~960℃ and a holding time of 1min~30min; subsequently, removing the sample from the heating zone for air cooling. The ultrathin oriented silicon steel strip of this invention achieves a larger average grain size, lower grain boundary density, and a Goss texture and {210}... <001> A texture-dominant, advantageous texture structure that effectively suppresses {123} <301> This invention addresses unfavorable textures, thereby significantly improving soft magnetic properties. By establishing an annealing condition coupling process window suitable for 0.08mm ultrathin oriented silicon steel strips, the invention achieves synergistic optimization of grain size, texture structure, and soft magnetic properties.

Description

Technical Field

[0001] This invention belongs to the field of electrical steel manufacturing, heat treatment and soft magnetic property control technology, specifically relating to a method for preparing ultra-thin oriented silicon steel strips of 0.08mm, achieving synergistic optimization of grain size, texture structure and magnetic properties. Background Technology

[0002] Grain-oriented silicon steel is an important soft magnetic functional material, widely used in high-efficiency motors, transformers, and high-frequency electromagnetic devices. Compared with conventionally thick grain-oriented silicon steel, ultra-thin materials have a natural advantage in reducing eddy current losses. However, their recrystallization kinetics, grain boundary migration behavior, and texture evolution after high-reduction-rate cold rolling are more complex. For 0.08mm grade materials, their high specific surface area and unique deformation energy storage distribution make the effects of annealing temperature and holding time more sensitive to the final microstructure and properties. If the annealing temperature is too low, recrystallization will be insufficient, resulting in fine grains and high grain boundary density, which can easily lead to enhanced magnetic domain wall pinning and increased coercivity. If the annealing temperature is too high or the holding time is too long, it may cause undesirable texture abnormal growth, texture diffusion, or even over-annealing, leading to a decrease in magnetic properties. Therefore, it is necessary to establish a primary recrystallization annealing process window suitable for 0.08mm ultra-thin grain-oriented silicon steel strips to obtain a microstructure with both low coercivity and high magnetic induction intensity. However, existing research largely focuses on the annealing process design of conventional thickness grain-oriented silicon steel materials, lacking systematic studies on the primary recrystallization behavior and the synergistic control of annealing temperature and holding time for 0.08mm diameter materials. Current technologies often employ multi-stage cold rolling or multi-level annealing processes, which are complex and lack stability, making it difficult to achieve synergistic optimization of grain size, texture, and magnetic properties while maintaining process simplification. Therefore, it is necessary to propose a primary recrystallization annealing process and preparation method for ultrathin grain-oriented silicon steel strips to clarify the coupled influence of annealing temperature and holding time on microstructure and magnetic properties, thereby obtaining stable and excellent soft magnetic properties. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing 0.08mm ultrathin oriented silicon steel strip. By synergistically controlling the initial base material, cold rolling thinning and primary recrystallization annealing process, an ultrathin oriented silicon steel strip with a large average grain size, a high proportion of favorable texture and excellent soft magnetic properties can be obtained.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing an ultrathin oriented silicon steel strip includes the following steps: S1. Select a 0.27mm thick high magnetic induction oriented silicon steel finished plate without a bottom layer as the initial base material, and remove its surface insulation layer and oxide layer. S2. The base material processed in step S1 is rolled to 0.08mm by precision cold rolling to obtain cold-rolled hard state ultra-thin oriented silicon steel strip; S3. The cold-rolled hard ultra-thin oriented silicon steel strip obtained in step S2 is subjected to initial recrystallization annealing in a vacuum environment. The annealing temperature is 900℃~960℃ and the holding time is 1min~30min. S4. After the heat preservation is completed, remove the sample from the heating zone and air cool it.

[0005] Further optimization involves using commercially available 0.27mm high-magnetic-induction oriented silicon steel Hi-B finished sheets without a bottom layer in step S1 as the initial base material. The initial base material undergoes pickling to thoroughly remove the surface insulation layer and oxide layer. The pickling step specifically involves placing the base material in an 18% hydrochloric acid (HCl) pickling solution and pickling it at 70℃~90℃, with slight stirring to accelerate the peeling of the surface insulation layer and oxide layer. After pickling, the base material is thoroughly rinsed with deionized water and then dried to obtain a clean base material suitable for subsequent precision cold rolling.

[0006] Further optimization is achieved by including the following chemical composition of the initial parent material by mass percentage: Si 3.0661%, Mn 0.1012%, Al 0.0034%, P 0.0179%, Sn 0.0488%, C < 0.005%, S < 0.005%, with the balance being Fe and unavoidable impurities.

[0007] Further optimization involves using a 20-roll precision cold rolling mill in step S2 to directly roll the 0.27mm base material to 0.08mm, achieving a total cold rolling reduction of 70% to obtain a cold-rolled hard-state sample. The working roll diameter of the mill is Φ30mm, and the surface roughness Ra of the working rolls is controlled at 0.3μm to ensure thickness control and surface quality during ultra-thin strip rolling. The rolling speed is controlled at 80m / min, which facilitates precise shape control under laboratory or pilot-scale conditions and helps prevent strip breakage. During rolling, mineral oil-based fully synthetic rolling oil is used for cooling and lubrication, with a flow rate controlled at 800L / min to reduce the friction coefficient and promptly remove deformation heat. Simultaneously, a pre-tension of 150–250MPa and a post-tension of 180–280MPa are applied, with the post-tension higher than the pre-tension, to improve the stable operation and centering performance of the strip in the roll gap. By controlling the above cold rolling parameters, the surface integrity, thickness accuracy, and consistency of the subsequent initial recrystallization treatment of 0.08mm ultrathin oriented silicon steel strip can be effectively guaranteed.

[0008] Further optimization is achieved by ensuring that the vacuum level of the vacuum environment described in step S3 is greater than 10. -3In the vacuum tube furnace environment of Pa, the annealing temperature in step S3 is selected from any one of 900℃, 930℃ or 960℃, and the holding time is selected from any one of 1min, 5min, 15min or 30min.

[0009] Further optimization was made, with the initial recrystallization annealing temperature in step S3 set at 960℃ and the holding time at 15 min.

[0010] Further optimization, after the initial recrystallization annealing in step S3, yields an ultrathin oriented silicon steel strip with an average grain size of 43 μm to 44 μm, and a Goss texture volume fraction of 30% to 40%, {210} <001> The texture volume fraction is 45%–50%, {123} <301> The texture volume fraction is no higher than 10%.

[0011] Further optimization, the Goss texture and {210} <001> The total volume fraction of the texture is not less than 80%.

[0012] Further optimization is achieved by ensuring that the saturation magnetic induction intensity of the obtained ultrathin oriented silicon steel strip after the initial recrystallization annealing in step S3 is not less than 1.95T and the coercivity is not higher than 31.08A / m.

[0013] On the other hand, the present invention also provides an ultrathin oriented silicon steel strip prepared by the above method, wherein the ultrathin oriented silicon steel strip has a thickness of 0.08 mm and has the following characteristics: <001> / / A favorable texture system based on RD.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: Firstly, using commercial Hi-B high magnetic induction oriented silicon steel finished sheets as the base material, its original high orientation degree structure is fully utilized to provide a favorable precursor for the inheritance of Goss texture in the subsequent large reduction rate cold rolling and primary recrystallization process; Secondly, the preparation route of directly cold rolling from 0.27mm to 0.08mm has a clear process flow, strong operability, and is suitable for forming ultrathin precursors for primary recrystallization research and application. Third, in vacuum conditions greater than 10 -3 Temperature-time coupled annealing at 900℃~960℃ for 1min~30min was carried out in Pa environment, followed by rapid air cooling after annealing, which helped to suppress surface oxidation of the sample and effectively freeze the microstructure and texture state after annealing. Fourth, the preferred process of holding at 960℃ for 15 minutes can significantly improve grain boundary mobility, increase the average grain size and reduce grain boundary density, thereby weakening the magnetic domain wall pinning effect and reducing coercivity. Fifth, the optimized process can promote Goss texture and {210} <001> Texture is dominant and significantly suppresses {123} <301> This method addresses unfavorable textures and achieves synergistic optimization of grain size, texture composition, and orientation sharpness. The process is simple and reproducible, significantly reducing coercivity while maintaining high magnetic induction intensity, providing an effective technical approach for the stable fabrication of ultrathin oriented silicon steel strips.

[0015] Sixth, this invention does not only regulate a single Goss texture, but constructs a system based on Goss texture and {210} <001> Dual benefits based on texture <001> / / RD easily magnetizable texture system. Since both types of textures share the common characteristic of being easily magnetizable along the rolling direction, a synergistically dominant advantageous texture cluster can be formed under the preferred annealing process of this invention. Results show that as the annealing temperature increases from 900℃ to 960℃, the Goss texture and {210}... <001> The overall texture integral increased from 56.8% to 83.7%, while {123} <301> Texture and {111} <110> The overall texture integral decreased from 39.58% to 8.55%, indicating that the present invention achieves a texture purification process that combines beneficial texture enhancement with detrimental texture attenuation, thereby significantly improving the magnetic induction intensity of the material along the rolling direction and reducing coercivity. Attached Figure Description

[0016] To more clearly illustrate the technical solutions involved in the embodiments of the present invention or the prior art, the accompanying drawings included in the description of the embodiments or the prior art will be briefly introduced below. It should be noted that these drawings only show some specific embodiments recorded in the present invention and do not cover all possible implementations.

[0017] Figure 1 This is a process flow diagram for the preparation of the ultrathin oriented silicon steel strip of the present invention.

[0018] Figure 2 The graph shows the effect of different annealing temperatures and holding times on the saturation magnetic induction intensity in Examples 1-12.

[0019] Figure 3 The graph shows the effect of different annealing temperatures and holding times on coercivity in Examples 1-12.

[0020] Figure 4 The diagram shows the typical texture component distribution of Examples 1-3 at different annealing temperatures.

[0021] Figure 5 The graph shows the change in the volume fraction of the favorable texture component in Examples 1-3 at different annealing temperatures.

[0022] Figure 6 The graph shows the changes in the volume fraction of unfavorable texture components at different annealing temperatures for Examples 1-3. Detailed Implementation

[0023] The technical solution of the present invention will now be described in detail and comprehensively. It should be noted that the embodiments described are only a part of the present invention and do not cover all embodiments. Furthermore, all other embodiments that can be obtained by those skilled in the art based on the embodiments provided by the present invention without creative effort should also fall within the protection scope of the present invention. In the following embodiments, unless otherwise specified, the instruments and materials used are commercially available.

[0024] The method for preparing ultrathin oriented silicon steel strip of the present invention selects commercially available 0.27mm high-magnetic-induction oriented silicon steel Hi-B finished plate without a bottom layer as the initial base material. The surface insulation layer and oxide layer are thoroughly removed by pickling. Subsequently, the base material is directly rolled to 0.08mm using a 20-roll precision cold rolling mill with a reduction rate of 70%, obtaining a cold-rolled hard state 0.08mm ultrathin oriented silicon steel strip. The obtained sample is then placed in a vacuum with a degree greater than 10... -3 The initial recrystallization annealing is performed in a vacuum tube furnace at a temperature of 900℃, 930℃, or 960℃, with holding times of 1 min, 5 min, 15 min, or 30 min. After holding, the material is immediately removed from the heating zone and air-cooled to freeze the high-temperature microstructure and texture. Preferably, the annealing process involves holding at 960℃ for 15 min. The preparation process of this invention can be summarized as follows: commercial high-magnetic-induction oriented silicon steel Hi-B base material → pickling to remove the insulating and oxide layers → 20-roll precision cold rolling to thin to 0.08 mm → vacuum initial recrystallization annealing (900℃~960℃) → air-cooled freezing microstructure.

[0025] Through the above process steps, the material achieves a larger grain size and favorable texture structure after initial recrystallization, thereby optimizing its magnetic properties. After this optimized process, the average grain size of the material is approximately 43.5 μm, and the Goss texture volume fraction is approximately 35.9%, {210} <001> The texture volume fraction is approximately 47.8%, {123} <301> The texture volume fraction drops to approximately 8%, forming a texture based on <001> / / A favorable texture system dominated by RD; the material's saturation magnetic induction intensity reaches 1.95T, and the coercivity is reduced to 31.08A / m.

[0026] The following is a further explanation with reference to specific embodiments: Example 1

[0027] A method for preparing an ultrathin oriented silicon steel strip includes the following steps: S1. Commercially available 0.27 mm high-magnetic-induction oriented silicon steel Hi-B sheet without a bottom layer was selected as the initial base material. Its chemical composition, by mass percentage, is: Si 3.0661%, Mn 0.1012%, Al 0.0034%, P 0.0179%, Sn 0.0488%, C < 0.005%, S < 0.005%, with the balance being Fe. The initial base material was thoroughly pickled to remove the surface insulation layer and oxide layer. The pickling step specifically involved placing the base material in an 18% hydrochloric acid (HCl) pickling solution and pickling it at 70°C with slight stirring to accelerate the peeling of the surface insulation layer and oxide layer. After pickling, the material was thoroughly rinsed with deionized water and then dried to obtain a clean base material suitable for subsequent precision cold rolling.

[0028] S2. The base material processed in step S1 is precision cold-rolled and thinned using a 20-roll precision cold rolling mill, directly rolling the 0.27mm base material to 0.08mm, with a total cold rolling reduction rate of 70%, obtaining a cold-rolled hard sample. The working roll diameter of the mill is Φ30mm, and the surface roughness Ra of the working roll is controlled at 0.3μm to ensure thickness control and surface quality during ultra-thin strip rolling. The rolling speed is controlled at 80m / min, which is beneficial for precise control of the strip shape under laboratory or pilot-scale conditions and helps prevent strip breakage. During the rolling process, mineral oil-based fully synthetic rolling oil is used for cooling and lubrication, with a flow rate controlled at 800L / min to reduce the coefficient of friction and remove deformation heat in time; at the same time, a front tension of 150MPa and a back tension of 180MPa are applied, with the back tension being higher than the front tension, to improve the stable operation and centering performance of the strip in the roll gap. By controlling the above cold rolling parameters, the surface integrity, thickness accuracy, and consistency of subsequent initial recrystallization treatment of 0.08mm ultrathin oriented silicon steel strip can be effectively guaranteed. S3. The cold-rolled hard-state ultra-thin oriented silicon steel strip obtained in step S2 is subjected to a vacuum degree greater than 10. -3 The initial recrystallization annealing was carried out in a vacuum tube furnace environment at 900℃ for 15 minutes. S4. After the heat treatment is completed, immediately remove the sample from the constant-temperature heating zone of the vacuum tube furnace, allowing it to quickly escape the predetermined annealing temperature field, and allow it to cool naturally in air at room temperature until the sample temperature drops to room temperature. During the removal process, it is preferable to use high-temperature resistant clamps to transfer the sample, and maintain the sample in a single layer, flat, and dispersed position to avoid differences in cooling rates caused by sample stacking, edge warping, or local contact. The purpose of this step is twofold: firstly, to promptly freeze the recrystallized grain morphology and grain boundary distribution formed during the high-temperature annealing stage, inhibiting further grain coarsening or abnormal growth during cooling; secondly, to maintain the Goss texture and {210} formed at high temperature. <001> This process ensures favorable texture advantages and avoids secondary texture evolution, orientation diffusion, or the resurgence of unfavorable texture components during cooling. After this step, the sample can better maintain the microstructure and texture characteristics of the final annealed state, providing a guarantee for obtaining a larger average grain size, lower grain boundary density, higher orientation sharpness, and excellent soft magnetic properties. Example 2

[0029] A method for preparing an ultrathin oriented silicon steel strip includes the following steps: S1. Commercially available 0.27 mm high-magnetic-induction oriented silicon steel Hi-B sheet without a bottom layer was selected as the initial base material. Its chemical composition, by mass percentage, is: Si 3.0661%, Mn 0.1012%, Al 0.0034%, P 0.0179%, Sn 0.0488%, C < 0.005%, S < 0.005%, with the balance being Fe. The initial base material was thoroughly pickled to remove the surface insulation layer and oxide layer. The pickling step specifically involved placing the base material in an 18% hydrochloric acid (HCl) pickling solution and pickling it at 80°C with slight stirring to accelerate the peeling of the surface insulation layer and oxide layer. After pickling, it was thoroughly rinsed with deionized water and then dried to obtain a clean base material suitable for subsequent precision cold rolling.

[0030] S2. The base material processed in step S1 is precision cold-rolled and thinned using a 20-roll precision cold rolling mill, directly rolling the 0.27mm base material to 0.08mm, with a total cold rolling reduction rate of 70%, obtaining a cold-rolled hard sample. The working roll diameter of the mill used is Φ30mm, and the surface roughness Ra of the working roll is controlled at 0.3μm to ensure thickness control and surface quality during ultra-thin strip rolling. The rolling speed is controlled at 80m / min, which is beneficial for precise control of the strip shape under laboratory or pilot-scale conditions and helps prevent strip breakage. During the rolling process, mineral oil-based fully synthetic rolling oil is used for cooling and lubrication, with a flow rate controlled at 800L / min to reduce the coefficient of friction and remove deformation heat in time; at the same time, a front tension of 200MPa and a back tension of 230MPa are applied, with the back tension being higher than the front tension, to improve the stable operation and centering performance of the strip in the roll gap. By controlling the above cold rolling parameters, the surface integrity, thickness accuracy, and consistency of subsequent initial recrystallization treatment of 0.08mm ultrathin oriented silicon steel strip can be effectively guaranteed. S3. The cold-rolled hard-state ultra-thin oriented silicon steel strip obtained in step S2 is subjected to a vacuum degree greater than 10. -3 The initial recrystallization annealing was carried out in a vacuum tube furnace environment at Pa, with an annealing temperature of 930℃ and a holding time of 15min. S4. After the heat preservation is completed, the sample is removed from the heating zone and air-cooled to effectively freeze the microstructure and texture under high temperature conditions, so as to obtain a 0.08mm ultrathin oriented silicon steel strip with synergistic optimization of grain size, texture composition and orientation sharpness. Example 3

[0031] A method for preparing an ultrathin oriented silicon steel strip includes the following steps: S1. Commercially available 0.27 mm high-magnetic-induction oriented silicon steel Hi-B sheet without a bottom layer was selected as the initial base material. Its chemical composition, by mass percentage, is: Si 3.0661%, Mn 0.1012%, Al 0.0034%, P 0.0179%, Sn 0.0488%, C < 0.005%, S < 0.005%, with the balance being Fe. The initial base material was thoroughly pickled to remove the surface insulation layer and oxide layer. The pickling step specifically involved placing the base material in an 18% hydrochloric acid (HCl) pickling solution and pickling it at 90°C with slight stirring to accelerate the peeling of the surface insulation layer and oxide layer. After pickling, it was thoroughly rinsed with deionized water and then dried to obtain a clean base material suitable for subsequent precision cold rolling.

[0032] S2. The base material processed in step S1 is precision cold-rolled and thinned using a 20-roll precision cold rolling mill, directly rolling the 0.27mm base material to 0.08mm, with a total cold rolling reduction rate of 70%, obtaining a cold-rolled hard sample. The working roll diameter of the mill used is Φ30mm, and the surface roughness Ra of the working roll is controlled at 0.3μm to ensure thickness control and surface quality during ultra-thin strip rolling. The rolling speed is controlled at 80m / min, which is beneficial for precise control of the strip shape under laboratory or pilot-scale conditions and helps prevent strip breakage. During the rolling process, mineral oil-based fully synthetic rolling oil is used for cooling and lubrication, with a flow rate controlled at 800L / min to reduce the coefficient of friction and remove deformation heat in time; at the same time, a front tension of 250MPa and a back tension of 280MPa are applied, with the back tension being higher than the front tension, to improve the stable operation and centering performance of the strip in the roll gap. By controlling the above cold rolling parameters, the surface integrity, thickness accuracy, and consistency of subsequent initial recrystallization treatment of 0.08mm ultrathin oriented silicon steel strip can be effectively guaranteed. S3. The cold-rolled hard-state ultra-thin oriented silicon steel strip obtained in step S2 is subjected to a vacuum degree greater than 10. -3 The initial recrystallization annealing was carried out in a vacuum tube furnace environment at 960℃ for 15 minutes. S4. After the heat preservation is completed, the sample is removed from the heating zone and air-cooled to effectively freeze the microstructure and texture under high temperature conditions, so as to obtain a 0.08mm ultrathin oriented silicon steel strip with synergistic optimization of grain size, texture composition and orientation sharpness. Example 4

[0033] The preparation method steps in this embodiment are the same as those in Embodiment 1, except that the heat preservation time in step S3 is 1 minute. Example 5

[0034] The preparation method steps in this embodiment are the same as those in Example 1, except that the heat preservation time in step S3 is 5 minutes. Example 6

[0035] The preparation method steps in this embodiment are the same as those in Example 1, except that the heat preservation time in step S3 is 30 min. Example 7

[0036] The preparation method steps in this embodiment are the same as those in Embodiment 2, except that the heat preservation time in step S3 is 1 minute. Example 8

[0037] The preparation method steps in this embodiment are the same as those in Embodiment 2, except that the heat preservation time in step S3 is 5 minutes. Example 9

[0038] The preparation method steps in this embodiment are the same as those in Embodiment 2, except that the heat preservation time in step S3 is 30 min. Example 10

[0039] The preparation method steps in this embodiment are the same as those in Example 3, except that the heat preservation time in step S3 is 1 minute. Example 11

[0040] The preparation method steps in this embodiment are the same as those in Example 3, except that the heat preservation time in step S3 is 5 minutes. Example 12

[0041] The preparation method steps in this embodiment are the same as those in Example 3, except that the heat preservation time in step S3 is 30 min.

[0042] The magnetic properties of the samples obtained in Examples 1 to 12 above were tested. The magnetic properties were tested using a vibrating sample magnetometer (VSM), the sample size was 10 mm × 8 mm × 0.08 mm, and the test temperature was room temperature. The microstructure analysis was performed using a scanning electron microscope equipped with an electron backscatter diffraction (EBSD) system, the accelerating voltage was 20 kV, and the scanning step size was 1.5 μm.

[0043] The results show that at 900℃, the saturation magnetic induction intensity of the sample is approximately 1.927T~1.936T, and the coercivity is approximately 42.67A / m~47.98A / m; at 930℃, the saturation magnetic induction intensity is approximately 1.920T~1.939T, and the coercivity is approximately 38.24A / m~46.09A / m; at 960℃, the saturation magnetic induction intensity is approximately 1.928T~1.950T, and the coercivity is approximately 31.08A / m~39.36A / m. Comprehensive comparison indicates that the performance is optimal when the sample is held at 960℃ for 15 minutes. Figure 2 , 3 As shown.

[0044] In Example 3, the average grain size of the material was approximately 43.5 μm, and the grain size was inversely proportional to the coercivity. Texture analysis showed that under these conditions, the Goss texture volume fraction was approximately 35.9%, {210} <001> The texture volume fraction is approximately 47.8%, while the unfavorable {123} <301> The texture volume fraction decreased to about 8%, indicating that high-temperature annealing promoted the purification and expansion of favorable textures.

[0045] Examples 3 and 10-12 involved holding the material at 960℃ for 15 min, 1 min, 5 min, and 30 min, respectively. The results showed that while the overall grain size increased with prolonged holding time, the magnetic properties did not increase monotonically. At 15 min, the sample achieved the lowest coercivity of 31.08 A / m and the highest saturation magnetic induction of 1.95 T. When the holding time was extended to 30 min, although the grains continued to grow, the magnetic induction decreased and the coercivity rebounded due to over-annealing, a decrease in Goss orientation sharpness, and an increase in stray orientation. Comparative analysis indicated that annealing at 900℃ or 930℃ resulted in a higher grain boundary density and stronger domain wall pinning effect due to insufficient recrystallization driving force or limited grain growth, thus maintaining a higher level of coercivity. In contrast, the preferred annealing process of the present invention, which involves holding at 960°C for 15 minutes, can effectively promote grain boundary migration and moderate grain growth, while maintaining favorable texture dominance, thereby obtaining the lowest coercivity and the highest saturation magnetic induction intensity.

[0046] The magnetic properties of Examples 1-12 under different annealing processes are shown in Table 1, and the typical texture volume ratio of Examples 1-3 under different temperature annealing processes is shown in Table 2.

[0047] Table 1 Magnetic properties under different annealing processes

[0048] Table 2 Typical texture volume percentage under different annealing temperatures

[0049] Table 2 shows that as the annealing temperature increases from 900℃ to 960℃, the favorable and unfavorable textures in the material exhibit a clear inverse evolution pattern. Among them, the Goss texture and {210}... <001> All textures belong to <001> / / RD easily magnetizable texture can be evaluated as a favorable texture component in this invention; {123} <301> Texture and {111} <110> Texture can be considered an unfavorable texture component. Statistical results show that at 900℃, 930℃, and 960℃, the overall scores of favorable textures were 56.8%, 70.5%, and 83.7%, respectively, showing a continuous upward trend; correspondingly, the overall scores of unfavorable textures were 39.58%, 29.2%, and 8.55%, respectively, showing a significant downward trend. Especially at 960℃, the Goss texture and {210} <001> The texture structure shifted from a competitive relationship in the mid-temperature stage to a cooperative dominant relationship, while {123} <301> The fact that unfavorable textures are significantly suppressed indicates that the preferred annealing process of the present invention can achieve the clustering of favorable textures and the purification of unfavorable textures, thereby providing a texture basis for obtaining excellent soft magnetic properties.

[0050] The technical solutions of this invention are not limited to the specific embodiments described above. Any technical modifications, alterations, substitutions, and variations made to the technical solutions of this invention without departing from the spirit and scope of the claims are within the protection scope of this invention.

Claims

1. A method for preparing ultrathin oriented silicon steel strip, characterized in that, Includes the following steps: S1. Select a 0.27mm thick high magnetic induction oriented silicon steel finished plate without a bottom layer as the initial base material, and pickle it to remove the surface insulation layer and oxide layer. S2. The base material processed in step S1 is rolled to 0.08mm by precision cold rolling to obtain cold-rolled hard state ultra-thin oriented silicon steel strip; S3. The cold-rolled hard ultra-thin oriented silicon steel strip obtained in step S2 is subjected to initial recrystallization annealing in a vacuum environment. The annealing temperature is 900℃~960℃ and the holding time is 1min~30min. S4. After the heat preservation is completed, remove the sample from the heating zone and air cool it.

2. The preparation method according to claim 1, characterized in that, The initial base material mentioned in step S1 is a commercial 0.27mm high magnetic induction oriented silicon steel Hi-B finished plate without a bottom layer; the pickling operation is specifically as follows: the base material is placed in a 18% hydrochloric acid (HCl) pickling solution and pickled at 70℃~90℃ with slight stirring. After pickling, it is rinsed thoroughly with deionized water and then dried.

3. The preparation method according to claim 2, characterized in that, The chemical composition of the initial parent material, by mass percentage, includes: Si 3.0661%, Mn 0.1012%, Al 0.0034%, P 0.0179%, Sn 0.0488%, C < 0.005%, S < 0.005%, with the balance being Fe and unavoidable impurities.

4. The preparation method according to claim 1, characterized in that, The precision cold rolling in step S2 is a 20-roll precision cold rolling with a rolling reduction rate of 70%. The working roll diameter of the cold rolling mill is Φ30mm, the surface roughness Ra of the working roll is controlled at 0.3μm, the rolling speed is controlled at 80m / min, and mineral oil-based fully synthetic rolling oil is used for cooling and lubrication during the rolling process with a flow rate controlled at 800L / min. At the same time, a front tension of 150-250MPa and a back tension of 180-280MPa are applied, with the back tension being higher than the front tension.

5. The preparation method according to claim 1, characterized in that, The vacuum level of the vacuum environment described in step S3 is greater than 10. -3 In the vacuum tube furnace environment of Pa, the annealing temperature in step S3 is selected from any one of 900℃, 930℃ or 960℃, and the holding time is selected from any one of 1min, 5min, 15min or 30min.

6. The preparation method according to claim 1, characterized in that, In step S3, the initial recrystallization annealing temperature is 960℃ and the holding time is 15min.

7. The preparation method according to claim 1, characterized in that, After the initial recrystallization annealing described in step S3, the average grain size of the resulting ultrathin oriented silicon steel strip is 43 μm to 44 μm, and the Goss texture volume fraction is 30% to 40%, {210} <001> The texture volume fraction is 45%–50%, {123} <301> The texture volume fraction is no higher than 10%.

8. The preparation method according to claim 7, characterized in that, The Goss texture and {210} <001> The total volume fraction of the texture is not less than 80%.

9. The preparation method according to claim 1, characterized in that, After the initial recrystallization annealing described in step S3, the saturation magnetic induction intensity of the obtained ultrathin oriented silicon steel strip is not less than 1.95T and the coercivity is not higher than 31.08A / m.

10. The ultrathin oriented silicon steel strip prepared by the method according to any one of claims 1 to 9, characterized in that, The ultra-thin oriented silicon steel strip has a thickness of 0.08 mm and has the following properties: <001> / / A favorable texture system based on RD.

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