Effect of Hot Band Grain Size on the Texture Evolution of 2%Si Non-Oriented Steel During Final Annealing

Industrial rough bar samples of 2%Si were hot rolled in a pilot reversing mill at different finishing temperatures. Hot rolled bands 2.3 mm in thickness were cold rolled to 0.50 mm and final annealed at different temperatures under H₂-N₂ atmosphere. To study the effect of hot band annealing, some samples were annealed at 1030 °C before cold rolling. Crystallographic texture and grain size (GS) were measured at the different processing steps. Magnetic properties were measured after final annealing. The results have shown that in case of finishing reversible hot rolling, hot band annealing may not result in benefit for magnetic properties due to the effect of static recrystallization between passes that already generates coarse hot band structure. Hot band GS has strong effect on final structure and magnetic properties. The increase of hot band GS has a beneficial effect on texture and magnetic polarization J₅₀ due to the increase of eta fiber fraction. However, large initial GS may result in smaller GS after final annealing due to intensive nucleation in shear bands on recrystallization. On further grain growth, the fraction of eta fiber grains tend to decrease, resulting in simultaneous decrease of J₅₀ and core loss.