METHOD OF MAKING COLD-ROLLED SEMIFINISHED ELECTRICAL STEEL Russian patent published in 2002 - IPC

FIELD: non-ferrous metallurgy; method of making cold-rolled semifinished electrical steel. SUBSTANCE: melted steel deoxidized slab is subjected to hot rolling, cold rolling and annealing; percentage of components is as follows: silicon, 0.01 to 1.6; aluminium, 0.02 to 0.5; carbon, no more than 0.07; manganese, 0.1 to 1.5; phosphorous, 0.01 to 0.20 and sulfur, no more than 0.025. Annealing of cold-rolled metal is performed in shielding gas atmosphere for 5.5 to 11 min at temperature according to the following relationship: K₁+K₂•Si±20^°C, where t is steel annealing temperature, ^°C; K₁= 600^°C% and K₂= 100^°C% are coefficients determined experimentally; Si is content of silicon in steel, mass-%. If necessary, hot-rolled strip is subjected after hot rolling (if required) to annealing at temperature of 820 to 950 C or cold-rolled steel is subjected after annealing to skin pass rolling at reduction of 2 to 8 %. EFFECT: improved electromagnetic properties of cold-rolled semifinished electrical steel. 3 cl, 2 tbl, 2 ex