CONTINUOUS PICKLING TANK WITH MULTISTAGE SUBMERGED ROLL FOR STEEL SHEET

PROBLEM TO BE SOLVED: To enable continuous pickling in a good productivity even for types of steel kinds having a poor descaling property by installing plural submerged rolls in juxtaposition into a pickling tank, alternately vertically passing a strip in the tank and making the submerged rolls arranged on the rear surface side of the strip vertically movable by means of lifting devices. SOLUTION: Three or more pieces of the submerged rolls 3a to 3q juxtaposed in the transverse direction of the steel sheet 2 are disposed in the continuous pickling tank 1. At least one piece of the rolls 3b, 3d, 3f between the first and last submerged rolls 3a and 3q on the inlet side and outlet side of the steel sheet 2 are arranged on the rear surface side of the steel sheet 2 and are made vertically movable in an arrowmarked lifting direction f2 by means of the submerged roll lifting devices 6. At the time of continuously pickling the steel sheet 2 by passing the steel sheet into a pickling liquid 4 via deflector rolls 5, the steel sheet is passed alternately between the rolls 3a and 3q of the multistages and the submerged rolls 3b... on the rear surface side are vertically moved according to the descaling property, by which the pass line is elongated and contracted and the immersion time is adjusted without lowering a line speed.