METHOD OF MAKING COLD-ROLLED ISOTROPIC ELECTRICAL STEEL Russian patent published in 2003 - IPC

FIELD: ferrous metallurgy; making cold-rolled isotropic electrical steel. SUBSTANCE: steel made according to proposed method includes the following components, %: silicon, up to 2; aluminum, 0.1-0.5; carbon, 0.015-0.065; phosphorus, 0.05-0.15; process includes two rolling cycles. Two-stage decarburizing annealing after first cold rolling cycle is performed at heating from first to second stage at rate 130-180 C/min. Second cold deformation cycle is performed by tension only, at specific tension of 1-4 kg/sq. mm. Final heat treatment is performed at temperature of 300-700 C. Heating from 1st to 2nd stage is performed at rate determined depending on content of carbon in steel by the following formula: V_1-2 =-1000 x [C] + 195, C/min, where V_1-2 is rate of heating from 1st to 2nd stage, C/min; -1000 is empirical coefficient, C/min/mas.%; [C] is content of carbon in steel, mas.%; 195 is empirical coefficient, C/min. Final heat treatment is performed at temperature determined by the following formula: T_final = 1000 x [A1] + 200, C, where T_final is temperature of final heat treatment, C; 1000 is empirical coefficient, C/mas. %; [A1] is content of aluminum in steel, mas.%; e00 is empirical coefficient, C. EFFECT: improved magnetic properties of steel. 3 cl, 1 tbl, 3 ex