| 摘要 |
PURPOSE:To obtain continuous cast billet of excellent surface shape capable of no-care rolling, by electromagnetically agitating the cast piece unsolidified part within the range of 1.5mm directed to the inside of inside of cast piece from the surface of cast piece so that an upward flow at specified flow rate may be achieved. CONSTITUTION:The contact surface between a molten metal 6 and a solidified layer 3 of maximum 15mm directed from the surface of cast piece to the inside of cast piece, in a mold 1 having an electromagnetic coil 2 built in, i.e. the molten metal 6 on the solidification boundary is electromagnetically agitated by a known means so that the flow rate directed from the lower part to the upper part may be 0.3-1m/sec. Since the majority of inclusion existing in said range is caused to collide against mold powder 4 and absorbed to be cleaned, the inclusion, slag, air bubbles, etc. on the cast piece surface layer part may be decreased. If the flow rate is more than 1m/sec, the molten metal 6 pushes the powder 4 into inside, and if the flow is less than 0.3m/sec, no effect is expected. Thus, production of cast piece with extremely small surface defect may be realized. |
