Patent ID: 10590509

Abstract:
A method for continuously annealing a steel strip includes annealing the steel strip in a vertical annealing furnace, an atmosphere in the furnace being separated by a partition disposed within a space spanning from the heating zone to the soaking zone. An atmosphere gas is supplied from an outside of the furnace into the furnace to form a furnace gas that is discharged from a steel strip entrance at a lower portion of the heating zone, a part of the furnace gas is sucked and discharged into a refiner including a deoxygenator and a dehumidifier such that oxygen and moisture in the part of the furnace gas are removed to form a gas having a lowered dew point, and the gas having a lowered dew point is returned into the furnace. The method further includes controlling a temperature of the steel strip passing through the partition to a range of 550° C. to 700° C.