METHOD FOR ON-LINE JUDGING SURFACE QUALITY OF CAST SLAB AND STEEL SLAB IN CONTINUOUS CASTING AND BLOOMING AND JUDGING INSTRUMENT

摘要

PROBLEM TO BE SOLVED: To drastically reduce the loss in the yield by keeping a scarfing amount for a steel slab to a minimum and to further improve the surface quality of the cast slab. ;SOLUTION: In a continuous casting process, in which molten steel 2 in a tundish 3 is poured into a mold 4 and the cast slab 5 is drawn out from the lower part of the mold 4 to form the cast slab into a bending shape and also, this cast slab is straightened with pinch rolls 6 and after being in a horizontal state, the cast slab is cut off and the cut-off cast slab 5 (B) is dipped into the cooling water 12 in a cooling water vessel 11 to fine the structure on the surface layer part of the cast slab, at the time of beforehand on-line judging the surface quality of the steel slab 15 after blooming in the stage of the cast slab 5 (B) after water cooling, the cast slab temp. before straightening with the pinch rolls 6, the water temp. in the water vessel before water-cooling the cast slab and the cast slab temp. before water-cooling, are continuously recorded. A tracking arrangement is executed and the surface quality of the cast slab 15 after blooming in the stage of the cast slab 5 (B) after water-cooling, is beforehand judged from each heat history in the unit of cast slab through a surface quality on-line judging means 28.;COPYRIGHT: (C)1999,JPO