| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent a tip biting defect, contraction at a tail end in tailing off and doubling up of a tail end and a tip end by starting rolling as setting at least a first one of a most tip end plate thickness to a specified value or more, thinning a plate thickness after wound on a coiler or near a joining point to a below specified value and returning a thickness before a most tail end of a last slab departs a finish last stand to a specified value or more when a steel slab of product tensile strength/a finish plate thickness of a below specified value are joined and continuously rolled. SOLUTION: A finish rolling mill 14 of hot rolling line consists of plural stands, a normal flying plate thickness change function is arranged on each stand. When steel slabs having product tensile strength of <400 MPa and a finish plate thickness of <1.2 mm are joined at a hot rolling line and is continuously finish rolled, at least a first one of a most tip end of continuous rolling is set to a plate thickness of >=1.2 mm, rolling is started, then a plate thickness of <1.2 mm is produced with using a flying plate thickness change function after wound on a coiler or near a joining point, a plate thickness is returned to >=1.2 mm before a most tail end of a last one departs a last stand.</p> |
