| 摘要 |
PURPOSE:To eliminate central segregation by making a billet to regular crystal near the solidification completion point and subjecting the billet just before the completion of solidification to a large rate of reduction by means of screw-down rolls. CONSTITUTION:At least a pair of large screw-down rolls 5 are disposed near the solidification end 2c of the billet 2 and an electromagnetic stirrer 4 is provided near the upper side thereof. Dendrite settles and the regular crystal zone is formed near the crater end when the stirrer 4 is operated near the solidification point of the billet 2 in the stage when said billet is continuously cast. The billet 2 just before the solidifaction completion point is subjected to the large rate of reduction of >=3mm. by means of the screw-down rollers 5 in the state of sandwiching the regular crystal zone in the central part. Since the billet is subjected to the large reduction near te solidification point in the regular crystal state of the unsolidified part 2b, the central segregation of the billet 2 is effectively eliminated without generating the crack within the boundary face. |
