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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]

• Low-finishing-temperature hot rolling and batch annealing result in large grains. • Prior large grains lead to desirable recrystallization microstructure and texture. • A potential processing method to improve magnetic properties is proposed. The grain size prior to cold rolling plays an important role in the microstructural, textural evolution and magnetic properties of non-oriented silicon steel sheets. In this work, we proposed a new way to obtain large grain size before cold rolling and applied it to a 1.0 wt% Si-0.2 wt% Al non-oriented silicon steel, i.e., appropriate low-finishing-temperature hot rolling combined with batch annealing. The grain growth process during batch annealing was investigated using a quasi in-situ electron backscattered diffraction (EBSD) technique. It was demonstrated that significant grain growth took place through a strain-induced boundary migration mechanism. Then a large number of in-grain shear bands were formed in the cold rolled microstructure and could provide nucleation sites for Goss ({1 1 0} 〈0 0 1〉) and λ-fiber (〈0 0 1〉//ND) recrystallized grains, thus resulting in a coarse-grained and homogeneous recrystallization microstructure with weakened γ-fiber (〈1 1 1〉//ND) texture, strengthened Goss and λ-fiber texture. Consequently, superior magnetic properties (B 50 = 1.763 T, P 1.5/50 = 4.30 W/kg) were obtained. For comparison, the conventional processing route without batch annealing was also investigated. A small-grained and inhomogeneous recrystallization microstructure with pronounced γ-fiber texture was produced in the finally annealed sheet, which could significantly deteriorate both the magnetic induction and iron loss. This work provided a new way to enlarge the grains in hot rolled sheets by low temperature batch annealing instead of the conventional high temperature normalization. Thus a new processing route to fabricate low silicon non-oriented electrical steels with high permeability and low iron loss was established. [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]