Cube oriented 3% Si-1% Mn soft magnetic steel sheets with fine grain structure

A process to produce cube oriented 3% Si-1% Mn steel sheets with a fine grain structure is introduced. The process consists of a conventional double stage cold-rolling and a decarburizing stack anneal with SiO₂-containing reactive separators for steels with an approximated chemistry of 3% Si-1% Mn-0.05% C. An almost complete decarburization is caused by a thermo-chemical reaction between stacked steel sheets and the separator under a reduced pressure at elevated temperatures. During this process, development of the cube texture, {100}⟨001⟩, takes place. Although the final grain size is as small as 0.4 mm in diameter, area coverage by the cube oriented grains reaches more than 90%. The magnetization at 800 A/m, B₈, in rolling and transverse directions amounts to 1.88 T, and the material exhibits a surprisingly low core loss of 1.2 W/kg or less at 1.7 T and 50 Hz