Influence Mechanism of Sn on 2.7%Si-0.5%Al Non-oriented Silicon Steel

Effects of Sn on microstructure, texture and magnetic properties of 2.7%Si-0.5%Al non-oriented silicon steel in industrial production were studied by X-ray diffraction and electron backscattering diffraction. Furthermore, combining first-principles simulation with White–Coghlan model calculation, grain boundary segregation of Sn was also investigated. In Sn-0.05 steel, cold-rolled sheet showed more ingrain shear bands and intensity of textures weakened significantly. Addition of Sn obviously reduced intensity of {111}<112> and increased intensity of {114}<481>; strong {100}<120> and nearly Goss textures appeared in annealed sheet. P_1.5/50 decreased by 0.05W/kg, B₅₀ increased by 0.005 T, and stability of magnetic properties were obviously improved of Sn-0.05. In the unit grain boundary layer (1 Å⁻²), the excess solute concentration on the grain boundary layer of Sn corresponding to 20,000–30,000 appm was 0.16–0.22 and gradually decreased with temperature and increased with intragranular solute content. As a segregation element, during annealing process of hot-rolled band and cold-rolled sheet, Sn exerted a drag force on the grain boundaries, thus inhibiting the grain growth. {114}<481> and {100}<120> oriented grains could grow selectively and distribute evenly by virtue of their mobility and quantity advantage higher than {111}<112>, thus improving magnetic properties and stability of 2.7%Si-0.5%Al non-oriented silicon steel.