| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide secondary cooling technology in continuous casting, allowing prevention of occurrence of a surface crack of a slab caused by supercooling even if casting speed is increased. <P>SOLUTION: In this secondary cooling method in the continuous casting, the surface of the slab having surface oxide scales and the mold powder remainder is cooled by water jetted from a cooling nozzle in the whole or a part of secondary cooling of the slab in the continuous casting for casting steel material. At least one of an average droplet diameter and an average water temperature of the jetted water is set to a state in which a slab surface temperature is higher than an MHF (Minimum Heat Flux) point that is a temperature point at which film boiling changes to transition boiling, in the cooling by the cooling nozzle. For example, the average droplet diameter of the water jetted from the cooling nozzle is set to be 200 μm or below. Alternatively, the average droplet diameter of the water jetted from the cooling nozzle is set to be 200 μm or above, and the water temperature is set to be 50°C or above. <P>COPYRIGHT: (C)2012,JPO&INPIT |
