LOW CORE LOSS-HIGH PERMEABILITY NON-ORIENTED SILICON STEELS   

Sebastião C. Paolinelli*, Marco A. da Cunha*

Alloy purity and crystallographic texture control can contribute to reduce core loss without the undesirable effects of increasing Si+Al content on the physical properties and cold workability.

This work discusses texture development and shows the importance of the structure prior to the cold rolling process on the texture and grain size obtained after final annealing, where recrystallization and grain growth take place. It also discusses the importance of boundary mobility on texture development and on grain growth in the final annealing. Rapid grain growth allows shorter time exposure of the steel to the annealing atmosphere and reduces the detrimental effects of nitration and oxidation.

The development described allowed successful industrial production of new low core loss-high permeability grades as E100-50, with core loss lower than 2.30 W/kg at the thickness of 0.50 mm and E100-35, with maximum core loss 1.95 W/kg at 0.35 mm, both with B₅₀ close to 1.70T.