CONTINUOUS CAST SLAB OF ALUMINUM-KILLED STEEL AND PRODUCING METHOD THEREFOR

摘要

PPROBLEM TO BE SOLVED: To further surely solve such problem caused by alumina cluster as a nozzle-clogging etc., when a continuous cast slab of aluminum-killed steel is produced. PSOLUTION: When the steel slab is produced by continuously casting after adding REM into the molten steel deoxidized with Al, the addition of the REM is performed by using Fe-Si-REM alloy containing ≤30 mass% REM and having ≤10mm grain size at ≤25g/min/ton of the molten steel of additional speed. In the steel slab produced in such way, as the number ratio of oxide-base inclusion of 1-10μm grain size interposed in the steel slab, the oxide-base inclusion of 0.5-15 mass% REM oxide concentration is ≥30%, the oxide-base inclusion exceeding 15 mass% REM oxide concentration is 10% and the rest is the oxide-base inclusion of 0.5 mass% REM oxide concentration. PCOPYRIGHT: (C)2008,JPO&INPIT