METHOD FOR JUDGING QUALITY OF CONTINUOUSLY CAST SLAB

摘要

PROBLEM TO BE SOLVED: To enable judging whether a cast slab can be rolled or not based on the produced quantity of Al oxide before hot rolling by grasping the producing quantity of Al oxide from lowering quantity of Al concn. in molten steel and grading the quality based on this produced quantity of Al oxide. SOLUTION: At the time of casting the cast slab 5 by pouring the molten steel 3 into a tundish 2 from a ladle 1 and successively, pouring the molten steel 3 into a mold 4 from the tundish 2, a free oxygen measuring sensor 6 is arranged into the molten steel 3 in the tundish 2 and the free oxygen value in the molten steel 3 is introduced to a computing element 7 and also, the molten steel temp. is introduced to always calculate the Al concn. in the molten steel 3. On the other hand, judgement of the quality grading the quality based on the produced quantity of Al oxide is executed by collating the lowering quantity of Al concn. from a correlation between the lowering quantity of Al concn. from the Al concn. in the molten steel 3 and the produced quantity of Al oxide beforehand introduced in the computing element 7. In such a way, since the suitable grading of the quality according to the quality can be executed and the judgement of the quality of the continuously cast slab 5 can accurately be executed, the defective quality in a consumer can be prevented.