METHOD OF PRODUCTION OF COLD-ROLLED STRIP Russian patent published in 2004 - IPC

FIELD: metallurgy; production of rolled steel; production of strip and sheet steels.

SUBSTANCE: proposed method includes hot rolling, pickling, cold rolling with emulsion, recrystallization annealing in bell-type furnace at stepped heating and control of composition of shielding medium. After cold rolling before annealing, material is kept for 8-24 h. Heating of rolls in bell-type furnace is started after cold blowing of under-muffle space with shielding medium for 2-3 hours. Annealing is performed at two intermediate delays at temperature of 560 C and 650 C. Sublimation and emulsion decomposition products are removed continuously from beginning of heating till intermediate delay at temperature of 650 C by delivery of shielding medium containing 4-7% of hydrogen and 93-96% of nitrogen at flow rate equal to flow rate of shielding medium at cold blowing. Infiltration of shielding medium from under-muffle space is effected continuously through sand lock from beginning of cold blowing till completion of cooling of annealed rolls under muffle at flow rate of shielding medium of 0.4-0.5 of flow rate during cold and hot blowing cycles.

EFFECT: improved quality of cold-rolled strip; reduced consumption of heat carriers; increased productivity.

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