| 摘要 |
PURPOSE:To completely prevent generation of surface flaws on slab ends by heating both lateral sides of a hot slab before and/or after drawing down the hot slab in the lateral direction. CONSTITUTION:A slab is heated so that lateral sides are at a temp. higher by a prescribed temp. than that in the lateral central part in the case of heating before width sizing. The slab is heated so that a temp. distribution in the lateral direction is uniform in the case of heating after sizing. For a heating method, any heating means of high-frequency or burner heating, etc., is usable; it is desirable to use a direct fire reducing gas burner heating method using reducing gas containing CO, or H2, etc., and having an air ratio not higher than a prescribed value. A hot slab of medium carbon steel is drafted by an edging press P and is rolled by rough rolling mill group 3 and a finish rolling mill group 4 to obtain a steel strip. The slab is heated by direct fire reducing burner 5 or 6 installed in the inlet or outlet side of the press machine P and then a steel strip is obtained by hot rolling stage. Hence, the yield and productivity of the hot rolling stage are improved. |
