Method of and apparatus for continuously or semi-continuously casting

Abstract

A method of continuously or semi-continuously casting an ingot of rectangular cross section in a vertical open-ended direct chill mold having a coolant passageway, wherein a flow of coolant is circulated and discharged from the bottom of the mold, and molten metal poured into the mold is solidified by applying the discharged flow of coolant directly to the peripheral surface of the metal emerging from the bottom of the mold. The method comprises a step of preventing a direct contact of the poured molten metal with an upper part of inner walls of the mold and controlling the cooling of the molten metal by the flow of coolant circulating in the passageway via the inner walls. The above step comprises interposing heat-insulating sheets between the upper part of the inner walls of the mold and the peripheral surface of the poured molten metal within the mold. The heat-insulating sheets are each dimensioned to satisfy predetermined formulas according to casting speed, mold size and other casting conditions such that a central portion of the sheet extends downwardly into the mold to a greater extend than the end portions thereof. An apparatus to practice the above method is also disclosed. The apparatus comprises the heat-insulating sheets which cover an upper part of inner walls of the mold and dimensioned and positioned according to the casting conditions.