METHOD AND APPARATUS FOR STRONG WIDTHHREDUCING ROLLING

摘要

PURPOSE:To restrict the thickness reduction at the middle part of the rolled material, and to improve the yield, by employing the slab possessing a convex section, and by installing new horizontal roll before and behind the vertical roll for carrying out the widfh-reducing rolling. CONSTITUTION:When the tip of slab 3 is to be rolled, if the circumferential speed of broadside rolling rolls 4, 5, is made quicker than the circumferential speed of the vertical roll 1, the middle part advances quicker than the edge part of the slab, and the fish tail of the slab edge is reduced. Besides, an elongation is caused in the lateral middle part, so that the generation of dog-bone is prevented. Next, when the tail end of the slab 3 is to be rolled, if the circumferential speed of broadside rolling rolls 4, 5, is made slower than the circumferential speed o the vertical roll 1, a tension is generated between the broadside rolling roll 5 and the vertical roll 1, and an elongation toward the lateral roll 5 middle part is caused, so that the fish tail is reduced. During the normal rolling pass, the circumferential speeds of broadside rolling rolls 4, 5, and the vertical roll 1 are made indentical. In case of the tandem edging mill, the boradside rolling roll 5 installed only behind the vertical roll 1 can serve satisfactorily.