PROCESS FOR THE PRODUCTION OF GRAIN ORIENTED MAGNETIC STEEL SHEETS HAVING IMPROVED REMAGNETIZATION LOSSES

摘要

The invention relates to a process for the production or grain oriented magnetic steel sheets having a finished strip thickness in the range of 0.1 mm to 0.5 mm from slabs having the alloy composition set forth in claim 1. The invention is characterized in that in addition to manganese and copper the slabs have an increased sulphur content and a reduced aluminium content; prior to hot rolling the slabs are heated to a reduced temperature and maintained for a sufficiently long period at such temperature, which is lower than the solution temperature of the manganese sulphides and higher than the solution temperature of the copper sulphides; the slabs are then if necessary first hot roughed and then finish rolled with a reduced final rolling temperature, preferably in the range of 900.degree.C to 980.degree.C, to the final thickness of the hot strip, whereafter hot strip annealing is performed, preferably in the range of 950.degree.C to 1100.degree.C. Single or two-stage cold rolling to the finished strip thickness, known recrystallizing annealing with simultaneous decarburization, the application of a separating agent, high temperature annealing and final annealing with an insulating coating result in grain oriented magnetic steel sheets. In comparison with the prior art (RGO and HGO), these sheets (TGO) have improved remagnetization losses for the same magnetic induction. Figure 4 is intended for the .