0.23 mm thick high permeability grain oriented Si-steel

We have developed a 0.23 mm thick high permeability grain oriented silicon steel (Hi-B) using AlN and MnS as grain growth inhibitors through the one stage cold rolling process. When the sheet thickness decreases, the secondary recrystallization tends to become unstable. We have successfully stabilized the secondary recrystallization of the thinner material by adding such alloying elements as tin and others. Magnetic properties of the newly-developed 0.23 mm thick Hi-B were superior to those of any other commercial grain oriented silicon steels. The core loss at 50 Hz of 0.23 mm Hi-B was about 0.66 W/kg at 1.5T and about 0.92 W/kg at 1.7T. Model transformer tests showed 0.23 mm thick Hi-B had excellent performance characteristics, especially when its surface was irradiated in cross rolling direction by laser. The relative economic value of 0.23 mm thick Hi-B as the material for transformers was estimated to be very high.