| 摘要 |
PROBLEM TO BE SOLVED: To restrain generation of surface imperfection on a casting piece such as an oscillation mark, surface fold and the like by applying a proper high frequency wave electromagnetic field to a meniscus portion from its side face. SOLUTION: A water cooling type oscillation mold 5 having a vertical direction slit 6 on its wall is used, and an electromagnetic coil 3 is arranged at the outer periphery of the mold. With this arrangement, a casting piece is pulled out to downwards while applying a high frequency electromagnetic field, which satisfies a following formula, in succession or intermittently against a casting time to a meniscus portion of a moten metal 7 in the casting mold. 0.0060+0.00057δ<=B1 <=0.0330+0.0014δ(B1 : flux of magnetic induction density (Tesla) in a vertical direction in an air-cored time at a position equivalent to a meniscus,δ=1,000×2/((ω×σ×μ)}<1/2> ," provided thatδ: surface skin depth (mm) of a molten metal,ω: an angular frequency wave number (Hz) of the magnetic field,σ: permeability (H/m) of the molten steel,μ: electric conductivity (l/Ωm) of the molten steel). However, a method to apply NS stage only is excluded.
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