The invention discloses a cold rolling method for high-magnetic-induction grain-oriented
silicon steel in the extremely thin specification. The method comprises steps as follows: (1) the thickness before rolling ranges from 2.0 mm to 2.5 mm, and normalization
pickling is performed; (2) the primary cold rolling method is adopted, and continuous reversible seven-pass cold rolling is performed: (2.1) rough-surface working rolls are adopted for the first five passes, and fine-surface working rolls are adopted for the last two passes; (2.2) the
reduction rate of each pass is controlled, the
reduction rate of the
first pass ranges from 30% to 45%, the
reduction rate of the last pass ranges from 18% to 31%, and the reduction rates of the rest passes range from 24% to 42%; (2.3) technological
lubrication and cooling are performed through
emulsion spraying; the plate temperature in the first three passes is controlled to gradually increased to 200-230 DEG C; the temperature is reduced for rolling in the fourth pass; the plate temperature in the subsequent passes is controlled to be 60-80 DEG C; (2.4) automatic plate
shape control is performed; (2.5) the rolling force in each pass is controlled to range from 250 T to 520 T; the unit tension on the entrance side of each pass is controlled to range from 2 kg / mm<2> to 20 kg / mm<2>, and the unit tension on the
exit side of the pass is controlled to range from 15 kg / mm<2> to 30 kg / mm<2>; (2.6) the product thickness after rolling ranges from 0.15 mm to 0.2 mm; (3) subsequent procedures are conducted conventionally. With the method, the production efficiency of the high-end
silicon steel in the extremely thin specification is substantially increased, and products are free of plate shape quality defects and are high in surface quality.