METHOD OF PRODUCING COLD-ROLLED ULTRALOW-SILICON ELECTRIC STEEL APPROPRIATE IN SWITCHING OFF MAGNETIC CONDUIT ELEMENTS Russian patent published in 1998 - IPC

FIELD: steelmaking. SUBSTANCE: invention relates to producing cold-rolled stock with high electromagnetic properties 0.5-1.1 mm thick which is designed to be applied when switching off magnetic conduit elements and having no rolling edges, chips, and other malformations from steel containing (in wt %): carbon, no higher than 0.1; manganese, 0.2-0.6; silicon, at most 0.04; phosphorus, at most 0.15; common admixtures including sulfur, chromium, nickel, copper, titanium, and nitrogen, not specified; and iron, the balance. Process involves annealing in continuously assemblies. According to invention, hot-rolled sheets 1.8-7 mm thick and characterized by rolling end temperature higher than Ar₃ and wound at temperature no higher than 620 C are subjected to etching and cold rolling with 70-80% reduction to final thickness. Cold-rolled sheets are degreased, washed out, and annealed in protective atmosphere at 590-650 C for 180-600 s, heating to annealing temperature being conducted with rate 8-16 C/s and cooling with uncontrolled rate to ambient temperature. When needed, heat treatment is followed by pinch rolling with 2.4-3.2% reduction. EFFECT: improved electromagnetic properties. 2 cl, 4 tbl