| 摘要 |
PURPOSE: A method for manufacturing a low-carbon sulfur-containing free-cutting steel slab is provided to secure billet surface quality after steel sheet rolling by reducing the generation of bubble-type hole defects under the superficial layer of the slab. CONSTITUTION: Molten steel, which comprises C: 0.03~0.15wt%, Mn: 0.70~1.60wt%, P: 0.05~0.10wt%, S: 0.2~0.5wt%, Al: 0.1wt% or less, [H]: 7ppm, and Fe and other inevitable impurities, is prepared. The molten steel is continuously casted using a continuous casting machine comprising a mold EMS(Electric Magnet Stirrer). The casted slab has a tensile strength of 35~55kg/mm^2 and hole defects less than 5 under the surface layer.
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