Conventional grain-oriented silicon steel (GO) relies on AlN/MnS-type inhibitors and long purification anneals, which increase alloy design complexity, energy consumption and cost. This study establishes a dislocation-loop-induced secondary recrystallization route in Fe-3 wt.% Si grain-oriented silicon steel produced by twin-roll strip casting with rare-earth Y microalloying. Steels containing 0, 0.05 and 0.1 wt.% Y were cold-rolled to 0.30 mm and subjected to primary and secondary recrystallization annealing. Electron backscatter diffraction (EBSD) reveals that 0.05 wt.% Y promotes {100}-oriented columnar solidification grains and strengthens the surface {111}⟨110⟩/{111}⟨112⟩ γ-fiber after rolling, increasing shear-band density and Goss nucleation sites while refining the primary-recrystallized matrix. Transmission electron microscopy shows abundant, thermally stable ⟨100⟩ dislocation loops (~50–100 nm) in Y-containing steels, rather than the commonly reported 1/2⟨111⟩ loops. These ⟨100⟩ loops act as effective grain-boundary pinning centers, suppressing normal grain growth and triggering abnormal Goss growth during high-temperature annealing. The 0.05 wt.% Y steel attains a secondary-recrystallization fraction of ~70%, with B₈ = 1.71 T and P_1.7/₅₀ = 2.81 W·kg⁻¹, whereas the Y-free alloy exhibits only normal grain growth and a weak Goss texture; excessive Y (0.1 wt.%) over-suppresses boundary mobility. The strong Y–vacancy affinity rationalizes the formation, thermal stability and potential recyclability of ⟨100⟩ loops, providing an inhibitor-free, energy-efficient pathway for manufacturing high-performance grain-oriented silicon steel.

The effect of warm-rolling on the microstructure, texture, and magnetic properties of ultra-low carbon yttrium (Y) -doped grain-oriented (Y-GO) Fe-3%Si steel as-cast strips were systematically investigated. Rare-earth Y atoms interact with dislocation-solute complexes to induce dynamic strain aging (DSA), which effectively promotes the formation of various shear bands during warm-rolling at 450 °C. Intensive and coarse shear bands were found in the warm-rolled specimens, providing additional nucleation sites for recrystallization. Meanwhile, the reduction in critical shear stress during warm rolling activates more slip systems, facilitates uniform deformation, and ultimately weakens the texture intensity. The grain size of the intermediate-annealed and primary-annealed specimens after warm rolling was significantly refined, indicating that the improved microstructure enhances secondary recrystallization. These results suggest that an optimal microstructure and texture in strip-cast yttrium-doped Fe-3%Si steel can be achieved through warm rolling, leading to an increase in magnetic induction B8 from 1.71 T to 1.81 T.