| 摘要 |
A tundish receiving molten metal and a cooled, closed-end mold are moved relatively apart so that the mold forms a solidified shell of a casting such as a billet, for example, molten metal flowing through the solidified shell to the mold. At least a portion of the closed end or plug of the mold is heated at least during a preheating period to limit or eliminate the formation of a solidifying metal membrane on at least a portion of the closed end. A lubricant and/or a seal may be introduced between an axial wall structure of the mold and the mold plug, and at least a portion of the mold is oscillated relatively to the shell in the mold during casting. The plug in one position thereof may occupy a forward or starting position in the end portion of axial wall structure nearest the tundish. In addition to preheating the tundish before receiving molten metal for flow therethrough, at least a portion of the plug is heated in its forward position during the preheating operation. The axial wall structure may be heated in the preheating operation to remove any condensation from the interior thereof. Thereafter, the near end face of the axial wall structure is abutted against a flange of the tundish prior to the flow of metal through the tundish to the mold. This retraction of the plug produces, with the axial wall structure coacting with the plug, a mold having a variable effective mold cavity.
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