METHOD FOR MANUFACTURING HOT STRIP

摘要

PURPOSE: A method for manufacturing hot strip is provided which not only improves control accuracy of a top end part of the hot strip, but also improves actual yield in the cold rolling process by properly controlling cooling process of the hot strip. CONSTITUTION: The method for manufacturing hot strip comprises the steps of setting target finishing delivery temperature (FDT), target coiling temperature (CT) and target threading velocity (v); obtaining an air cooling temperature drop (CTair) using the set target finishing delivery temperature and target threading velocity; obtaining a target strip temperature (MTt) at the middle of run out table using the measured finishing delivery temperature (AFDT) and the obtained air cooling temperature drop; obtaining a water cooling total temperature drop (TN) using the obtained target strip temperature and the target coiling temperature; obtaining water cooling temperature drop (TWi) for respective cooling banks positioned in feedforward control region; sequentially adding up the obtained water cooling temperature drop values for the respective cooling banks from the cooling bank in the rearmost side of the feedforward control region to cooling banks at the front side of the feedforward control region; obtaining a water injection starting cooling bank in which the added value of the respective cooling banks is the same as or more than the water cooling total temperature drop; starting cooling of the hot strip by injecting cooling water onto the hot strip through the water injection starting cooling bank when the top end of the hot strip passes through the obtained water injection starting cooling bank; and cooling the hot strip by an ordinary manner from a time point when the hot strip is coiled on a down coiler.