METHOD FOR COOLING CONTINUOUSLY CAST BILLET

摘要

PURPOSE: A method for cooling continuously cast billet is provided to avoid generating heat cracks and to enhance the efficiency of a continuously casting process. CONSTITUTION: In case that a billet contains less than each 0.05% of adding elements except for C, Mn and Si, a hardenability index is obtained by a formula in which the hardenability index = ( 0.5444 * C(%) + 0.0008) * (3.3331 * Mn(%) + 1.0002) * (0.7 * Si(%) + 1). When the hardenability index is less than 0.55, the billet is cooled with water regardless of cooling water temperature. When more than 0.55 to 0.65, the billet is cooled with water in more than 48deg.C of the cooling water temperature. When more than 0.65, the billet is cooled with air. In case that the billet contains more than each 0.05% of adding elements except for Mn and Si, the billet is cooled with air.