PRODUCTION OF CONTINUOUS CASTING BILLET HAVING NO SEMI-MACRO SEGREGATION

摘要

PURPOSE:To prevent bulging to be generated in a billet and to produce the billet having no semi-macro segregation, in the stage of producing the billet by a continuous casting method, by rolling down lightly the specific position of a solidus phase line under a specific draft. CONSTITUTION:Rolling rolls 7 are set at =450mm. inter-roll pitch, and are installed in at least 2m range from the crater end 6 of a solidus phase line 2 toward the upper stream side. Then a billet 4 is lightly rolled down by as much as the volumetric shrinkage thereof as the solidification of the solid-liquid coexistence phase existing in said range progresses, thereby preventing the flow of the molten steel having a high solute concn. in the solid-liquid coexistence phase. The draft by the rolls 7 is 0.5mm./m.