A ROLLING PROCESS FOR THE PREPARATION OF GRAIN ORIENTED ELECTRICAL STEEL SHEET USING LOW TEMPERATURE REHEATING METHOD

摘要

Grain oriented electrical steel sheet is produced through a low temperature (1200°C) reheating method. The sheet is rolled to its final thickness through a two-stage rolling process comprising hot rolling, intermediate annealing followed by warm rolling, while the cold rolling is restricted to only 5% for imparting surface finish. First rolling stage is hot rolling comprising of 4 passes while the second stage is essentially warm rolling comprising of 2 passes. The volume fraction of austenite phase at each pass of hot rolling, deformation at each pass, temperature a t each pass, inter-pass time and cooling rate are strictly controlled to obtain sharp Goss texture component in the surface and sub-surface of the sheet. These Goss oriented grains will grow selectively to abnormally large Goss grains of size 10-15mm during secondary recrystallization annealing, which would impart good soft magnetic properties to the sheet for use in core of electrical transformers.