Study on the Recrystallization Behavior and Texture Evolution of 0.5 mm Electromagnetic Pure Iron Cold-Rolled Strip

The control of recrystallization in submillimeter-gauge electromagnetic pure iron strips is critical for developing high-sensitivity electromagnetic devices, yet the microstructure–property relationship during annealing remains poorly understood. This study systematically investigates the recrystallization topology, texture evolution, and their direct links to the electromagnetic properties in an industrially produced 0.5 mm thick DT4 electromagnetic pure iron cold-rolled strip (80% reduction) during annealing at 900 °C. By combining EBSD, XRD, and VSM, we found that recrystallization initiates at shear bands after 7 s and completes within 25 s, yielding equiaxed grains with an average size of 27.5 μm. Prolonged annealing to 180 s led to grain coarsening to 64 μm. Concurrently, the fraction of low-angle grain boundaries decreased dramatically from 69.6% to 9.09%. The recrystallization texture, dominated by oriented nucleation at shear bands, showed a stable γ-fiber component (~20% volume fraction) and a significantly attenuated α-fiber component (decreasing from 66.3% to 21.5%). The Goss texture ({110}<001>) increased notably from 0.54% to 14.0%, attributable to grain boundary energy minimization in the later stages. Recrystallization kinetics obeyed the JMAK model X_rex = 1 − exp (−2.29 × 10⁻⁸ t^6.434). Crucially, the completed recrystallization process reduced the coercivity (Hc) by 78.5% and increased the magnetic induction B₁₀₀₀₀ by 0.045T. These findings elucidate the recrystallization mechanism and establish a quantitative microstructure–property correlation, providing a theoretical foundation for optimizing industrial annealing processes for thin-gauge electromagnetic pure iron strips.