NON-ORIENTED SILICON STEEL SHEET AND METHOD

摘要

A non-oriented silicon steel sheet having a low core loss contains Si in an amount of about 2.5 - 5.0 wt% and S restricted to about 0.003 wt% or less and inclusions; the volume ratio of those inclusions having a particle size of about 4 .mu.m or higher to the total volume of inclusions is about 5 - 60 %, and the volume ratio of inclusions having a particle size less than about 1 .mu.m to the total volume of inclusions is about 1 - 15 %; when the sheet contains Mn in an amount of about 0.4 - 1.5%, and the volume ratio of particles less than 1 .mu.m is about 1 - 5 %, the silicon steel sheet also has a low rotation core loss. The method of manufacturing comprises controlling the change of a cooling speed to about 5.degree.C/s2 or less in the cooling process of such steel sheet in a finish annealing.