OPERATION OF EQUIPMENT FOR PRODUCING COLD-ROLLED STEEL SHEET AND PLATED STEEL SHEET

PURPOSE:To quicken the switching of a cold-rolled steel sheet producing stage to a plate steel sheet producing stage and to remarkably reduce the stopping time of the line by using a vapor-deposition plating device on the overageing chamber delivery side of a continuous heat-treating furnace for steel sheet. CONSTITUTION:A first vapor-deposition chamber 3 and a second vapor-deposition chamber 4 are provided in succession to the overageing chamber 2 of the continuous heat-treating furnace and respectively in opposition to both sides of a delivered steel sheet 1, and the chambers 2 and 3 and the chambers 3 and 4 are respectively connected by vacuum devices 5 and 6. The steel sheet 1 leaving the chamber 2 is introduced into the chamber 3 via the device 5. In this process, the atmosphere of the steel sheet 1 is depressurized to a specified vacuum, one side of the steel sheet 1 is vapor-deposition plated in the chamber 3, the steel sheet 1 is then introduced into the chamber 4 via the device 6, and the other side is vapor- deposition plated. The atmosphere of the steel sheet 1 is returned to atmospheric pressure while the steel sheet 1 is passed through a vacuum device 7, and the steel sheet 1 is dipped in a water tank 8 and cooled. Meanwhile, when a cold-rolled steel sheet is produced, the chambers 3 and 4 are not used, the operation of the chamber 3 and/or chamber 4 is turned on or off, and both-sides or one-side plated steel sheet producing stage can be easily switched to the cold-rolled steel sheet producing stage or vice versa.