METHOD FOR PREVENTING SURFACE CRACK OF CONTINUOUSLY CAST SLAB

摘要

PROBLEM TO BE SOLVED: To provide a method for preventing surface cracks in slabs where, even in the case of steels comprising large quantities of elements such as Nb, V, Al, B and N, even if each slab after casting is carried to a hot rolling stage as the following stage as being high temperature without performing surface inspection and surface grooming, steel products free from surface defects caused by the surface cracks of each slab can be produced. SOLUTION: In continuously cast slabs 13, 13a, only the surface layer of each slab is cooled from the temperature range of an Ar3transformation point or above to the temperature range of an Ar1transformation point or below at a cooling velocity of≥300°C/s, and thereafter, the surface temperature of each continuously cast slab is again heat-recuperated to the temperature range of an Ar3transformation point or above. COPYRIGHT: (C)2007,JPO&INPIT