Iron loss of tertiary recrystallized silicon steel

Tertiary recrystallization was observed after cold-rolling and annealing of conventional silicon steels. The magnetic induction B/sub 8/ at 800 AA/m of tertiary recrystallized sheets about 75- mu m thick is as high as 1.97 T. Magnetic domain width in these sheets is greater than 1 mm; hence domain-refining techniques such as mechanical scratching and chemical etching are employed in order to reduce the iron loss. The iron loss of the sheet mechanically scratched under the application of a tensile stress of 4 kg/mm/sup 2/ is W17/50=0.42 W/kg and W13/50=0.19 W/kg. However, this domain-refining effect disappears after annealing for 30 min at 800 degrees C. On the other hand, domain refining by the chemical etching is effective against iron loss even if the sheets are annealed; the loss of a sheet 71- mu m thick under the application of a tensile stress of 4 kg/mm/sup 2/ is W17/50=0.35 W/kg and W13/50=0.17 W/kg. The iron loss of a chemically etched sheet with a thickness of 31 mu m is W17/50=0.21 W/kg and W13/50=0.13 W/kg. >