Production of high silicon steel for electrical applications by thermomechanical processing

The objective of this work is to investigate a method by which high silicon alloys containing up to 6.5% Si can be processed by rolling applying hot–cold working techniques. Alloys with 4.5 and 6.3% Si were cast, hot and cold rolled using an adequate scheme. A final thickness of 1 mm after hot rolling and 0.4 mm after cold rolling was obtained. After hot rolling a heterogeneous microstructure is observed over the sheet thickness: shear bands in the surface and a central zone with elongated grains. The recrystallisation is strongly retarded at low temperature and specifically in the high Si steel probably because of ordering. The microstructure of the cold rolled material is similar to the hot rolled microstructure, due to the lack of recrystallisation. After annealing for 2 h at 900 °C secondary recrystallisation is observed and texture is weakened.