| 摘要 |
PROBLEM TO BE SOLVED: To effectively prevent development of breakout by predicting a sign of the breakout with a remarkable accuracy in comparison with the conventional method. SOLUTION: In thermocouple lines disposed in two steps at the upper and the lower parts in the width direction of a mold for continuous casting, when detecting rapid change in the temperature within a time (t1) satisfying the following formula (1) between the mutually adjacent thermocouples in the adjacent three points of the thermocouples at the upper step and also, when developing the rapid change of the temperature within a time (t2) satisfying the following formula (2) to the lower step thermocouple just below the thermocouple firstly detecting the rapid change in the upper step three point thermocouples, the casting speed is reduced. W.tanθmin/(αmax.Vc)<=t1<=W.tanθmax/(αmin.Vc)...(1), H/(αmax.Vc)<=t2<=H/(αmin.Vc)...(2). Wherein, W: The distance (mm) between the mutually adjacent thermocouples, H: The distance (mm) between the thermocouples at the upper and the lower steps, Vc: Casting speed (m/min),αmin andαmax: The minimum and the maximum propagation speed rates to the casting speed of the above break line respectively andθmin andθmax: The minimum and the maximum propagation angles ( deg.) in the above break line, respectively.
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