ELECTROMAGNETIC STIRRING METHOD OF MOLTEN STEEL IN CONTINUOUS CASTING

摘要

PURPOSE:To provide good solidified structure to a billet in the stage of drawing the billet contg. a specific amt. of carbon by stirring the unsolidified part thereof in the casting direction under specific conditions by an electromagnetic stirrer in the position where said part has a specific thickness. CONSTITUTION:An electromagnetic stirrer is provided in the drawing position where the thickness of the unsolidified part of a billet consisting of a middle carbon steel contg. 0.15-0.45% carbon with respect to the entire thickness in the thickness direction thereof attains 15-25% in the stage of casting continuously said billet. The unsolidified part is stirred in the casting direction by said device in such a way that the product of the magnetic flux density (unit: gauss) at the boundary between the unsoldified part and the solidified part and the stirring time [the ratio between the effective length (mm.) of stirring with the electromagnetic stirrer/the drawing speed (m/min) of the billet in minute] attains 1,650- 2,000gauss/min with respect to the square of the drawing speed of the billet. The unsolidified part is stirred in the drawing position where the thickness thereof is 15-45% in the case of a high carbon steel contg. >=0.7% carbon.