STEEL-STRIP PRODUCTION METHOD, AND STEEL STRIP

A steel-strip production method according to the present invention is characterized in that a hot-dip-plated steel strip and a cold-rolled steel strip are produced by using a production apparatus 1 having a continuous annealing furnace 2, a snout 6 connected to the continuous annealing furnace 2, a contact-type seal plate device 10 and a noncontact-type seal roll device 20 that are arranged on the entry side of the snout 6 along the transfer direction of a steel strip S in this order, a hot-dip-plating tank 5 that is movable, and an in-tank immersion sink roll 31 configured to turn the path direction of the steel strip S after passing through the snout 6; and the production apparatus 1 includes a hot-dip-plated steel strip production unit configured to produce a hot-dip-plated steel strip by bringing the steel strip S continuously annealed in the continuous annealing furnace 2 into a hot-dip-plating tank 5, and a cold-rolled steel strip production unit configured to produce a cold-rolled steel strip by transferring the steel strip S continuously annealed in the continuous annealing furnace 2 without causing the steel strip S to pass through the hot-dip-plating tank 5, using a deflector roll arranged at the position of the in-tank immersion sink roll 31, the production apparatus 1 being capable of switching between the hot-dip-plated steel strip production unit and the cold-rolled steel strip production unit.