Deformation heterogeneity and its effect on the recrystallisation texture of non-oriented electrical steel

Non-oriented electrical steel (NOES) is the most commonly used material for the manufacturing of soft magnetic cores for electric motors. The magnetic properties of the steel lamination, which have a significant effect on the energy efficiency of electric motors, are highly dependent on the microstructure and crystallographic texture of the steel. The final microstructure and texture of the NOES are closely related to the thermomechanical processing history of the material, especially the deformed microstructure and texture before final annealing. This is because both nucleation and grain growth during recrystallisation are determined by the microstructure/substructure and texture of the material after cold deformation. During cold rolling, the plastic deformation does not occur in a homogeneous manner in metals, which usually leads to heterogeneous deformation substructures, including shear bands, deformation bands, transition bands, etc., which play a crucial role in determining the final microstructure and texture. In this paper, the formation of deformation heterogeneity during cold rolling of NOES and its effect on the subsequent recrystallisation are investigated using electron backscatter diffraction (EBSD) techniques. The relationships between the deformation substructures and the recrystallisation texture are discussed.