US 4,582,112 AGranted

Weight-controlled casting of fully-killed steel ingots

AssigneeUnited States Steel Corporation

InventorJay O. Mack

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Abstract

In the ingot casting of killed-steel steels, insulative walled reservoirs known as hot-tops are employed at the top of the mold to maintain a source of molten steel which can feed the shrinkage cavity that forms during solidification of the ingot. Presently, these hot-tops are set to a predetermined height prior to the filling of the mold cavity. As a result of such controlled height pourings, variations in the volume of the mold cavity lead to significant losses in the ingot-to-product yield. To overcome such losses, the invention employs a floating hot-top. Rather than teeming to a prescribed height, the ingot is teemed to a prescribed weight and the floating hot-top is placed on the surface of the steel so teemed. Further pouring is delayed, at least until the hot top is welded to the surface by the freezing of the molten steel in contact therewith. Thereafter, the hollow center of hot-top is filled to provide a sufficient reservoir of molten metal for the resultant shrinkage cavity.

Claims3

Dependent claims

In the production of killed-steel ingots, wherein steel is teemed into a mold cavity to effect solidification therein, such solidification resulting in the formation of a shrinkage cavity in the upper central portion of the ingot, and a hot-top lined with a heat-loss preventive material is utilized so that the top portion of the ingot remains molten for a longer period than the main body of the ingot whereby said top portion may furnish a pool of molten steel to fill the shrinkage cavity in the main body portion below said hot-top,

the improvement for preventing loss of ingot-to-product yield, due to variations in the volumes of the mold cavity, which comprises,
(a) teeming a predetermined weight of steel into the mold, said weight being determined by the downstream weight requirements of the production line,
(b) placing an annular-shaped hot-top on the top surface of the steel in the mold, said hot-top having a density low enough so as to not appreciably displace molten steel beneath it and force such steel into the hollow center of the annular hot-top said hollow center having an internal volume greater than that required to fill the resulting shrinkage cavity,
(c) after the steel has frozen along the points where the bottom surface of said hot-top contacts the top surface of the steel, resuming the teeming of steel into the hot-top hollow center, in an amount sufficient to fill the shrinkage cavity below said hot-top.

1 more element

Dependencies are inferred from the claim text.