PROCESS FOR THE PRODUCTION OF GRAIN-ORIENTED MAGNETIC SHEET STARTING FROM THIN SLAB

摘要

Process for the production of grain-oriented magnetic sheets, wherein a slab made of steel having a thickness of =100 mm, containing Si in the range comprised between 2.5 and 3.5% by weight, is subjected to a thermo-mechanical cycle comprising the following operations: ° optional first heating to a temperature T1 no higher than 1250°C ° first rough hot-rolling, in a first rough hot rolling mill, to a temperature T2 comprised between 900 and 1200°C, the reduction ratio (% Rid) applied to the first rough hot-rolling being adjusted so as to be: - of at least 80%, in the absence of a subsequent heating to a temperature T3 - determined by the following relationship % Rid=80 (T3 -T2)/5, in the presence of a subsequent heating to a temperature T3 ° optional second heating to a temperature T3 > T2 ° second finishing hot-rolling, in a second finishing hot rolling mill, to a temperature T4 < T3 to a thickness of the rolled section comprised in the range of 1.5 mm - 3.0 mm ° cold-rolling, in one or more stages, with optional intermediate annealing, wherein in the last stage a cold reduction ratio no lower than 60% is applied ° primary recrystallisation annealing, optionally in a decarburizing atmosphere ° secondary recrystallisation annealing. Subject of the invention is also the grain-oriented magnetic sheet obtainable from this process.