| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the development of flaw etc., after rolling caused by powder entrapped into molten steel with boiling and improve the quality by surely detecting the development of the boiling on the molten steel surface in a mold for a continuous caster. SOLUTION: The molten steel surface level in the mold for continuous casting is measured and the distribution of amplitudes of frequency component in the measured values is used and the ratio r=y1 /y2 of the average value (y1 ) of the amplitudes of the frequency component in a low frequency zone and the average value (y2 ) of the amplitudes of the frequency component in a high frequency zone, is calculated. A boiling index (b) is obtd. from the relational expression b=(1-r)×100. In the case of executing this boiling index (b) to a preset threshold value (br ) for a fixed time or larger, it is judged to develop the boiling and reversely, in the case of being less than this value for a fixed time or longer, it is judged to develop no boiling to detect the boiling.
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