JPS5739019A - Controlling method for sheet breadth in hot rolling process - Google Patents

Abstract

PURPOSE: To correct the shape of a slab having a part of greatly narrowed breadth, and to manufacture a steel sheet with uniformly shaped side edges, by reducing the edging roll gap just in front of the breadth narrowed part of the slab, by widening the edging roll gap at the breadth narrowed part, and then, by giving a horizontal reduction to the hereby formed swelling part of the slab.

CONSTITUTION: A slab 1 is fed in the arrowed direction to an edging roll 2 in order to apply an edging process to the slab 1; then, a broadside rolling process is applied to the slab 1 by a horizontal mill 3 in order to determine the breadth of the sheet on the run-out side of the mill 3. Hereupon, if there is a breadth narrowed part 8 as a result of a defect trimming process, etc., a defect trimming information input unit 6 determines a lacking amount of breadth of the slab 1 and a lacking amount of its thickness from the trimming depth (d). The unit 6 detects the longitudinal position of the defect trimmed part, that is the length l from the top end of the slab 1 to the defect trimmed position, for example, and inputs it to a defect trimming compensation arithmetic unit 5. The unit 5 determines the gap of edging rolls 2 and gives a command for adjusting the edging roll gap to an edging roll gap controller 4, which then adjusts the gap of the edging rolls 2. The edging roll gap is reduced just in front of the breadth narrowed part of the slab 1, and is widened at the breadth narrowed part; then, a horizontal reduction is given to the swelling part of the slab 1, and hereby, a steel sheet hardly having the breadth narrowed part as a whole is manufactured.

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