Goss texture regulation and control method for oriented silicon steel

Abstract

The invention relates to an oriented silicon steel Goss texture regulation and control method. The method comprises the steps of steelmaking, continuous casting, hot rolling, normalizing, cold rolling, primary recrystallization annealing and secondary recrystallization annealing. Wherein the reduction rate of each pass of cold rolling is 30%-40%; the temperature of the primary recrystallization annealing plate is controlled to be 800-830 DEG C, and the time is 3-6 minutes; and the temperature of the secondary recrystallization annealing plate is controlled to be 900-1150 DEG C, and the time is 0.25-4 hours. Compared with the prior art, the method has the beneficial effects that the proportion of Goss seeds in a primary recrystallization structure after primary recrystallization annealing and the orientation environment of crystal grains around the Goss seeds are regulated and controlled by controlling the cold rolling process and the primary recrystallization annealing process, so that the Goss crystal grains rapidly grow in the secondary recrystallization process of secondary recrystallization annealing, and the yield of the Goss crystal grains is improved. The magnetic induction intensity B800 of the oriented silicon steel with the thickness specification of 0.20 mm can reach 1.85-1.95 T, and the magnetic induction intensity B800 of the oriented silicon steel with the thickness specification of 0.18 mm can reach 1.92-1.98 T.

Description

Technical Field

[0001] The invention relates to the technical field of metal materials, and in particular to a method for controlling the Goss texture of oriented silicon steel. Background Art

[0002] Oriented silicon steel is one of the important functional materials in the electrical industry. Its magnetic properties directly affect the efficiency and performance of equipment such as motors, transformers and generators. The sharp Goss texture is a direct factor in the excellent magnetic properties of oriented silicon steel.

[0003] The production of oriented silicon steel involves processes such as steelmaking, continuous casting, hot rolling, normalizing, cold rolling, primary recrystallization annealing and secondary recrystallization annealing. The texture type in the silicon steel undergoes multiple changes from hot rolling to secondary recrystallization annealing, from the typical rolling texture of hot rolling and cold rolling to the annealing texture of primary recrystallization annealing. Finally, in the secondary recrystallization annealing stage, inhibitors and other factors are used to allow Goss grains to swallow up other oriented grains and grow.

[0004] The origin of Goss grains is related to the surface structure of hot-rolled plates. They are retained in situ after normalization. After cold rolling with a large deformation of 80%-92%, Goss grains are finely dispersed and appear in the middle of the deformation zone of the center layer of the cold-rolled plate. The first recrystallization annealing process can retain 1-5% of Goss grains. Under the action of secondary recrystallization annealing and inhibitors, Goss grains swallow up other grains and grow rapidly. Current academic research shows that Goss grains are more likely to swallow up γ textures and α* textures such as {114}(841) and {113}(631) and grow rapidly, while competing with brass {110}(112) and other near-Goss textures. Without discussing the role of inhibitors, mainstream academics believe that adjusting the ratio of γ texture and α* texture in carbon annealing is conducive to obtaining high-sharp Goss texture.

[0005] The present invention allows Goss grains to obtain greater growth dynamics driving force by regulating the proportion of primary recrystallized Goss grains and the orientation of grains around the Goss grains, so that they can quickly swallow up surrounding grains and grow rapidly, thereby obtaining a high-sharp Goss texture in the oriented silicon steel product. Summary of the invention

[0006] The present invention provides a method for regulating the Goss texture of oriented silicon steel. By controlling the cold rolling process and the primary recrystallization annealing process, the proportion of Goss seeds in the primary recrystallization structure after the primary recrystallization annealing and the orientation environment of the grains around the Goss seeds are regulated, so that the Goss grains grow rapidly during the secondary recrystallization annealing and secondary recrystallization process, thereby obtaining a finished oriented silicon steel product with a high sharp Goss texture and improving the magnetic properties of the oriented silicon steel.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for controlling Goss texture of oriented silicon steel comprises steelmaking, continuous casting, hot rolling, normalizing, cold rolling, primary recrystallization annealing and secondary recrystallization annealing; wherein the reduction rate of each cold rolling pass is 30% to 40%; primary recrystallization annealing is performed in a nitrogen atmosphere, during which the plate temperature is controlled at 800 to 830°C for 3 to 6 minutes; secondary recrystallization annealing is performed after the steel plate is cooled to room temperature, during which the plate temperature is controlled at 900 to 1150°C for 0.25 to 4 hours.

[0009] After steelmaking, continuous casting, hot rolling and normalizing, the oriented silicon steel obtains a normalized plate with a thickness of 2.0 to 2.6 mm.

[0010] The normalized plate is cold rolled to 0.18-0.27 mm, and the cold rolling passes are adjusted to 4-7 passes according to the thickness, with a reduction rate of 30%-40% for each pass. Under this cold rolling process, a strong deformation structure and strong α and γ textures are obtained.

[0011] The grain size of the primary recrystallization structure after primary recrystallization annealing is 35±5μm, the Goss seed texture accounts for 0.4% to 1%, and there is α around the Goss grains. * and γ texture wrapping.

[0012] After secondary recrystallization annealing, the product is cooled to room temperature. Under this process, the Goss grains grow fully, the secondary recrystallization grain size is 30 to 50 mm, the grain boundaries are smooth, and there are no defects such as island crystals.

[0013] Table 1 shows the cold rolling process parameters corresponding to some thickness specifications of the present invention

[0014] Table 1 Cold rolling process table for different thicknesses

[0015] Serial number Thickness(mm) path Pass reduction rate 1 0.27 4-5 35％-40％ 2 0.23 4-6 35％-40％ 3 0.20 5-7 30％-35％ 4 0.18 5-7 30％-35％

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention discloses a method for regulating Goss texture of oriented silicon steel. By controlling the cold rolling process and the primary recrystallization annealing process, the proportion of Goss seeds in the primary recrystallization structure after the primary recrystallization annealing and the orientation environment of the grains around the Goss seeds are regulated, so that the Goss grains grow rapidly during the secondary recrystallization annealing and secondary recrystallization process, and then a high-sharp Goss texture oriented silicon steel product is obtained to improve the magnetic properties of the oriented silicon steel. The magnetic induction intensity B of the oriented silicon steel with a thickness of 0.20 mm is 800 Up to 1.85-1.95T, 0.18mm thickness specification oriented silicon steel magnetic induction intensity B800 It can reach 1.92-1.98T. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the EBSD test data map of the cold-rolled structure after hot-rolling process regulation in Example 1 of the present invention.

[0019] Figure 2 This is the EBSD test data map of the primary recrystallization structure after the primary recrystallization annealing process is regulated in Example 1 of the present invention.

[0020] Figure 3 This is the EBSD data map of the finished plate and the industrial plate after secondary recrystallization annealing in Example 1 of the present invention.

[0021] Figure 4 This is the ODF spectrum of the finished plate after secondary recrystallization annealing in Example 2 of the present invention. DETAILED DESCRIPTION

[0022] The specific implementation modes of the present invention are further described below in conjunction with examples. The following examples are used to specifically illustrate the contents of the present invention. These examples are only general descriptions of the contents of the present invention and do not limit the contents of the present invention.

[0023] Embodiment 1:

[0024] The oriented silicon steel industrial normalized plate was used as the initial plate for 6 passes of cold rolling, from 2.3 mm to 0.18 mm, with a total reduction of 92.17%. The pass reduction rates were 34.95%, 34.96%, 34.99%, 34.98%, 35.00% and 32.58%, respectively. The cold rolled structure was shown in the attached figure. Figure 1 As shown in the figure, the texture types are α and γ, among which the rotational cubic texture intensity reaches 20, and the γ orientation line texture intensity is 4-5. The cold rolled sheet is subjected to primary recrystallization annealing in nitrogen atmosphere at 820℃ / 3min. The primary recrystallization structure is shown in the attached figure. Figure 2 As shown, the grain size is 35.54 μm and the texture type is α * and γ textures, of which Goss texture accounts for 0.62%. The Goss grains and surrounding grains are enlarged in the selected area, and it can be seen that the Goss grains are composed of α * The texture and the γ textures such as {111}(112) provide a good initial growth condition for the Goss grains. The secondary recrystallization annealing temperature is 1200℃ / 4h, which provides a good dynamic driving force for the growth of the Goss grains during the secondary recrystallization process to obtain a high-sharp Goss structure with a final grain size of 35-50mm. The Goss structure finally obtained by the present invention is as shown in the attached figure. Figure 3As shown in the figure (left side of the dotted line), the Goss orientation in the grain is accurate and sharp, the texture strength reaches 190, the grain boundaries between the grains are smooth, the orientation is sharp, and B 800 is 1.931T. Compared with industry products (attached Figure 3 The grain boundary is not smooth, there are a lot of island crystals inside the grains, the sharpness of the Goss grains is low, and the near-Goss texture grows into island crystals. 800 It is 1.916T.

[0025] Embodiment 2:

[0026] Oriented silicon steel industrial normalized plate was used as the initial plate for 6 cold rollings, from 2.2mm to 0.20mm, with a total reduction of 90.91%, and the pass reduction rates were 34.34%, 34.26%, 34.86%, 33.31%, 30.46% and 30.31% respectively, of which the rotational cubic texture strength reached 31, and the γ-oriented line texture strength was 4-5. The primary recrystallization annealing was carried out at 820℃ / 3min in a nitrogen atmosphere, with a grain size of 25μm and a Goss grain ratio of 0.47%. After the secondary recrystallization annealing at 1200℃ / 4h, the final grain size was 40-50mm, the Goss texture was sharp, and the strength reached 300 (attached Figure 4 ), B 800 It is 1.913T.

Claims

1. A method for controlling Goss texture of oriented silicon steel, characterized in that: It includes steelmaking, continuous casting, hot rolling, normalizing, cold rolling, primary recrystallization annealing and secondary recrystallization annealing; wherein the reduction rate of each cold rolling pass is 30% to 40%; during the primary recrystallization annealing, the plate temperature is controlled at 800 to 830°C for 3 to 6 minutes; during the secondary recrystallization annealing, the plate temperature is controlled at 900 to 1150°C for 0.25 to 4 hours.

2. The method for controlling Goss texture of oriented silicon steel according to claim 1, characterized in that: The thickness of the normalized plate after normalization is 2.0 to 2.6 mm.

3. A method for controlling Goss texture of oriented silicon steel according to claim 1 or 2, characterized in that: The normalized plate is cold rolled to a diameter of 0.18 to 0.27 mm, and the number of cold rolling passes is 4 to 7.

4. The method for controlling Goss texture of oriented silicon steel according to claim 1, characterized in that: The grain size of the primary recrystallization structure after the primary recrystallization annealing is 35±5 μm, the Goss seed texture accounts for 0.4% to 1%, and there is α * and γ texture wrapping.

5. The method for controlling Goss texture of oriented silicon steel according to claim 1, characterized in that: The secondary recrystallization grain size after the secondary recrystallization annealing is 30-50 mm, the grain boundary is smooth, and there is no island crystal defect.

6. The method for controlling Goss texture of oriented silicon steel according to claim 1, characterized in that: The primary recrystallization annealing was performed in a nitrogen atmosphere.

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