METHOD AND APPARATUS FOR PRODUCING THICK-WALLED HOLLOW BILLET

摘要

PURPOSE:To make possible the continuous casting of a thick-walled hollow billet without defects by covering the part of a water-cooled core upper than the casting surface with a refractory heat insulating material to lower the solidification initiation points on the water-cooled core side so as to position the same on the casting surface of a water-cooled metallic mold lower than the refractory heat insulating material. CONSTITUTION:A molten metal 15 is supplied into the spacing between the water-cooled casting mold 10 and the water-cooled core 1 and a receiving base 12 is so lowered as to maintain the solidification initiation points P1 and P2 in the positions shown in the figure. The point P2 is forcibly pushed down onto the casting surface 1a by the refractory heat insulating material 2 and the lowermost point 15a of the sump is brought to the position near the casting surface 1a of the water-cooled core 1 by the combination of the cooling from the mold 10 and the cooling from the core 1 positioned relatively below. The substantial sump depth is therefore the depth shown by a code H1 and the substantial sump depth H1 which the cause for the cracking arising from shrinkage on solidification is extremely diminished. The thorough prevention of the cracking is thus made possible.