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Herein, four kinds of initial Goss textures with different deviation angles (0°, 5°, 10°, and 15°) are obtained by controlling the included angles between the longitudinal directions of rectangular cutting specimens and the initial rolling direction of the raw material. Then, 0.05 mm thick grain‐oriented silicon steels are fabricated by cold rolling and primary recrystallization annealing. Effects of initial textures on the microstructure and texture evolutions and magnetic properties are investigated in detail. Compared with sharp {111}<112> in the cold rolling sheet with initial exact Goss, the deviated Goss favors the formation of strong {111}<112> + weak {h11}<1/h 1 2> textures. After annealing, sharp {210}<001> + medium {110}<001> textures develop as a result of the small initial deviation, while larger initial deviations contribute to the {310}<001> texture. In addition, the average grain sizes are also related to recrystallization textures. Consequently, the distinct recrystallization microstructures and textures result in the differences of magnetic properties. [ABSTRACT FROM AUTHOR]

0.05–0.15 mm-thick ultra-thin grain-oriented silicon steel sheets were successfully produced by a novel processing route including strip casting, hot rolling, normalizing, two-stage cold rolling with intermediate annealing, primary recrystallization annealing and secondary recrystallization annealing. The evolutions of microstructure, texture and inhibitor along the processing were briefly investigated. The results showed that the initial Goss orientation originated due to the heterogenous nucleation of δ-ferrite grains during solidification. Because of the lack of shear deformation, only a few Goss grains were observed in the hot rolled sheet. After the first cold rolling and intermediate annealing, Goss texture was enhanced and distributed in the whole thickness. A small number of Goss grains having a high fraction of high energy boundaries exhibited in the primary recrystallization annealed sheet. A large number of fine and dispersed MnS and AlN and a few co-precipitates MnS and AlN with the size range of 10–70 nm were also observed. Interestingly, a well-developed secondary recrystallization microstructure characterized by 10–60 mm grains and a sharp Goss texture were finally produced in the 0.05–0.15 mm-thick ultra-thin sheets. A magnetic induction B 8 of 1.72–1.84 T was obtained. Another new finding was that a few {2 3 0}〈0 0 1〉 and {2 1 0}〈1 2 7〉 grains also can grow up abnormally because of the high fraction of high energy boundaries and the size and number advantage, respectively. These non-Goss grains finally deteriorated the magnetic properties of the ultra-thin sheets. In addition, low surface energies of {hk0} planes may also contribute to the abnormal growth of Goss, {2 3 0}〈0 0 1〉 and {2 1 0}〈1 2 7〉 grains. [ABSTRACT FROM AUTHOR]

In this work, a 0.71 wt%Si+0.44 wt%Al as-cast strip was produced by novel twin-roll casting. Some as-cast samples were respectively reheated and hot rolled at different temperatures in order to obtain different microstructure prior to cold rolling and annealing. The effects of the hot rolled microstructure on microstructure, texture evolution and magnetic properties were investigated in detail. A coarse deformed microstructure with λ-fiber texture was formed after hot rolling at 850–1050 °C, finally leading to an inhomogeneous recrystallization microstructure with strong λ-fiber, Goss and extremely weak γ-fiber texture. By contrast, a fine transformed microstructure was formed after hot rolling at 1150–1250 °C, finally leading to a fine and homogeneous recrystallization microstructure with stronger α-fiber, γ-fiber and much weaker λ-fiber texture. It should be noted that both the magnetic induction and core loss non-monotonically decreased or increased according to the hot rolling temperature. The unfavorable α-fiber and γ-fiber textures in the annealed sheets were much weaker than those of the conventional products regardless of the hot rolling temperature, thus contributing to a much higher magnetic induction. However, the average grain size in the annealed sheets was much lower than those of the conventional products regardless of the hot rolling temperature, thus leading to a higher core loss except the case of 1050 °C. Hence, it is underscored that better integrated magnetic properties than those of the conventional products can be obtained by optimizing the hot rolled microstructure to produce final desirable recrystallization microstructure and texture. [ABSTRACT FROM AUTHOR]

A 0.27 mm-thick grain-oriented silicon steel sheet with extra-low carbon was successfully produced by a novel processing route including strip casting, normalizing, two-stage cold rolling with an intermediate annealing, primary annealing, and secondary recrystallization annealing. The evolutions of microstructure and texture along the whole processing route were investigated with a special emphasis on the effects of two-stage cold rolling schedule. It was found that Goss orientation originated in the first cold rolling due to shear banding and relatively strong Goss texture evolved through the whole thickness after intermediate annealing. This is significantly different from the results in conventional process in which the origin of Goss texture is in the hot rolling stage and Goss texture only develops below the sheet surface. Besides, it was found that cold rolling schedule had significant influences on microstructure homogeneity, evolution of λ-fiber texture in primary annealed state and, thus, on secondary recrystallization. In case of appropriate cold rolling schedule, a homogeneous microstructure with Goss texture, relatively strong γ-fiber texture and medium α-fiber texture was observed in the primary annealed strip. Although Goss texture in primary annealed state was much weaker than that in two-stage route in conventional process, a perfect secondary recrystallization microstructure was produced and the magnetic induction B was as high as 1.85 T. By contrast, when the cold rolling schedule was inappropriate, the primary annealed strips exhibited inhomogeneous microstructure, together with weak γ-fiber texture, medium α-fiber and λ-fiber texture. Finally, the sheets showed incomplete secondary recrystallization microstructure in which a large number of fine grains still existed. [ABSTRACT FROM AUTHOR]

A 0.23 mm thick grain-oriented silicon steel sheet was successfully produced based on strip casting and two-stage cold rolling route. The evolutions of microstructure and texture along the complete processing route were briefly investigated. It was shown that the as-cast strip was composed of coarse ferrite grains and martensite, and the texture was mainly characterized by strong {001} $\langle 0vw\rangle $ texture. Goss texture was absent in the hot-rolled strip, which was distinct from the well accepted results that Goss texture had its origin during hot rolling. After the cycle of the first-stage cold rolling, an intermediate annealing, the second-stage cold rolling, and a primary annealing, the strip exhibited a fully recrystallized microstructure with a weak \alpha $ -fiber texture and a relatively strong \gamma $ -fiber texture. Goss texture was not observed through the thickness of the primary annealed strip. This was significantly different from the previous results that Goss texture was the most populous component in the primary recrystallization texture of two-stage route in conventional process. After secondary recrystalization annealing, the magnetic induction of the sheet was as high as 1.84 T. [ABSTRACT FROM AUTHOR]

Secondary recrystallization is responsible for the sharp Goss texture ({110}<001>) of grain-oriented electrical steels. Many investigations have focused on establishing the relations between the sharpness of final Goss textures and primary recrystallization textures measured by the X-ray diffraction. However, the contributions of micro-texture characteristics to secondary recrystallization have not yet been well understood. Here, we report that the grain colonies composed of grains with similar orientations in the primary recrystallization matrix had a particular role on the development of secondary recrystallization via an original tracking experiment. We observe that the γ-grain (<111>//normal direction, ND) colonies facilitate the retention of primary recrystallization matrix grains (≤25µm) having 20-45° disorientation with {110}<001> and relatively large difference in the associated frequency with precise Goss orientation and that having deviation angle of 15°, promoting the abnormal growth of low-deviation-angle Goss grains especially after the onset of secondary recrystallization and leading to sharp final Goss texture. By contrast, the abnormal growth of high-deviation-angle Goss grains may be also promoted after the initiation of secondary recrystallization in case of randomly-distributed γ-grains in primary recrystallization matrix and thus resulted in deteriorated magnetic properties. In this way, we reveal the role of grain colony on secondary recrystallization and the underlying mechanism for the effect of primary recrystallization textures on the sharpness of final Goss texture. We also observe that the formation of grain colonies is mainly related to the initial solidification microstructure, processing route as well as the deformation and recrystallization features of γ-grains. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• Ultra-thin sheets were produced based on primary recrystallization. • Dependence of texture evolution on initial Goss orientation was clarified. • Different cold rolled and recrystallization textures evolved in Hi-B and CGO. • Mechanism of recrystallization of typical texture was investigated. • Relationships of iron loss upon grain size, texture and thickness were clarified. Based on cold rolling and primary recrystallization method, 0.05–0.15 mm-thick ultra-thin grain-oriented silicon steel sheets were successfully produced by utilizing the high induction (Hi-B) and common grain-oriented (CGO) silicon steels as raw materials, respectively. Thus, the effects of sharpness of initial Goss texture on the evolutions of microstructure, texture and magnetic property were investigated in detail. For Hi-B steel, 'smooth' microstructures were formed in the cold-rolled sheets, and the textures evolved along the following path: exact {1 1 0}〈0 0 1〉 → {2 3 0}〈0 0 1〉 → {1 1 1}〈1 1 2〉. By contrast, significant deformation bands or shear bands were observed in the CGO steel, and the textures developed along the following path: deviated {1 1 0}〈0 0 1〉 → {2 1 0}〈0 0 1〉 → {1 1 1}〈1 1 2〉. After annealing, inhomogeneous microstructures containing some clusters with large grains (∼2–4 mm) and fine equiaxed grains appeared in the Hi-B steel and the associated texture evolution with increasing cold rolling reduction followed the path: {1 1 0}〈0 0 1〉 → {2 3 0}〈0 0 1〉 → {2 1 0}〈0 0 1〉. Unlike the Hi-B steel, relatively fine and uniform equiaxed recrystallization grains were produced in the final CGO steel, and the texture evolved along the route: {2 1 0}〈0 0 1〉 → {6 1 0}〈0 0 1〉. Consequently, further research focusing on the recrystallization mechanism was studied. The results showed that {1 1 0}〈0 0 1〉 and {2 1 0}〈0 0 1〉 developed into the predominated components due to oriented growth and oriented nucleation respectively in the 0.05 mm-thick Hi-B sheet, while {1 0 0}〈0 0 1〉 became the main texture with the aid of oriented nucleation advantage in the CGO sheet. In addition, more attention was paid on the magnetic properties of the ultra-thin sheets, and the results showed that heavy cold rolling reduction as well as low annealing temperature contributed to better magnetic induction. Furthermore, the separated iron loss components were obtained to clarify the relationships between the iron loss and grain size, texture and thickness. [ABSTRACT FROM AUTHOR]

• Effect of two-stage cold rolling route on microstructure and texture was studied. • Low-reduction cold rolling and intermediate annealing resulted in coarse grains. • γ-Fiber was weakened while λ-fiber and Goss texture were enhanced in final sheet. • Increasing grain size prior to cold rolling led to improved magnetic properties. The 0.5 mm-thick Fe-0.9 wt%Si-0.3 wt%Al non-oriented electrical steel sheets were successfully produced with one-stage and two-stage cold rolling methods. The comparative investigations were conducted on the relationships between the processing routes, microstructures, textures and magnetic properties. This study mainly focused on how to increase the grain sizes prior to cold rolling and its influences on subsequent microstructure and texture evolution. The results showed that the fine microstructure prior to final cold rolling led to the pronounced γ-fiber texture, fine recrystallized grains and deteriorated magnetic properties after final annealing. Nevertheless, by introducing a low-reduction cold rolling and intermediate annealing, coarse grains could be generated prior to the final cold rolling. When the cold rolling reduction was 11%, a relatively homogeneous microstructure composed of fully coarse grains was produced. The increased grain sizes promoted the generation of dense shear bands during final cold rolling, which served as the nucleation sites for λ-grains and Goss grains. This resulted in the improved magnetic properties due to the weakened γ-fiber texture, strengthened λ-fiber texture and Goss texture and increased grain sizes in the final annealed sheets. This work provided a new way to improve the magnetic properties of non-oriented electrical steels by controlling the grain sizes prior to final cold rolling. [ABSTRACT FROM AUTHOR]

The microstructure and texture evolution along the processing was investigated with a particular focus on the secondary recrystallization behavior in a 0.23 mm-thick twin-roll cast grain-oriented electrical steel. A striking feature is that Goss orientation originated during twin-roll casting as a result of shear deformation and it was further enhanced during hot rolling and normalizing. After primary recrystallization annealing, a homogeneous microstructure associated with a sharp γ-fiber texture was produced. During secondary recrystallization annealing, the γ-fiber texture was first strengthened and weakened with increasing temperature prior to the onset of secondary recrystallization. Goss grains always exhibited more 20–45° misoriented boundaries than the matrix. The matrix was quite stable during secondary recrystallization with the aid of dense inhibitors. Finally, a complete secondary recrystallization microstructure consisting of large Goss grains was produced. The grain boundary characteristics distribution indicated that the high energy model was responsible for the abnormal growth of Goss grains under the present conditions. [ABSTRACT FROM AUTHOR]

A 0.1 mm-thick grain-oriented silicon steel sheet was successfully produced using strip casting and three-stage cold rolling method. The microstructure, texture and inhibitor evolution during the processing was briefly analyzed. It was found that Goss texture was absent in the hot rolled sheet because of the lack of shear deformation. After normalizing, a large number of dispersed MnS precipitates with the size range of 15–90 nm were produced. During first cold rolling, dense shear bands were generated in the deformed ferrite grains, resulting in the intense Goss texture after first intermediate annealing. The microstructure was further refined and homogenized during the subsequent cold rolling and annealing processes. After primary recrystallization annealing, a homogeneous microstructure consisting of fine and equiaxed grains was produced while the associated texture was characterized by a strong γ-fiber texture. Finally, a complete secondary recrystallization microstructure consisting of entirely large Goss grains was produced. The magnetic induction B 8 and iron loss P 10/400 was 1.79 T and 6.9 W/kg, respectively. [ABSTRACT FROM AUTHOR]