Newly developed grain-oriented Si-steel with thinner gauges

A new inhibitor system of MnSe and AlN incorporating Sb has exhibited a strong inhibition effect, i.e.strong suppression of normal grain growth in 3% silicon steel. The texture of primary recrystallized grains was considerably improved by (1) rapid step cooling after the intermediate-annealing, (2) dynamic aging during second cold-rolling, and (3) retarded primary recrystallization owing to Sb addition. This improvement resulted in highly aligned secondary recrystallization within average mis-orientation angle less than 3° from the ideal (110)[001]. Finished material showed much improved magnetic properties: The iron loss of 0.27 mm thick material, domain-refined with grooves formed in the sheet surface, was less than 0.80 W/kg at 1.7T,50Hz. Model transformer experiments exhibited 12% lower iron loss with the improved material than conventional one.