Abstract: A method and apparatus is disclosed for casting a composite ingot made of metals that are susceptible to surface oxide formation when molten. The method involves co-casting at least two metal layers from at least two molten metal pools formed within a direct chill casting apparatus. During the casting operation, movement of metal oxide formed on the upper surface of at least one of the pools towards an edge of the pool is restrained by an oxide skimmer positioned close to an edge of the pool above an external surface or metal-metal interface of the ingot. The apparatus provides a DC caster with at least one oxide skimmer that operates in this manner.

Abstract: A method of casting a metal ingot with a microstructure that facilitates further working, such as hot and cold rolling. The metal is cast in a direct chill casting mold, or the equivalent, that directs a spray of coolant liquid onto the outer surface of the ingot to achieve rapid cooling. The coolant is removed from the surface at a location where the emerging embryonic ingot is still not completely solid, such that the latent heat of solidification and the sensible heat of the molten core raises the temperature of the adjacent solid shell to a convergence temperature that is above a transition temperature for in-situ homogenization of the metal. A further conventional homogenization step is then not required. The invention also relates to the heat-treatment of such ingots prior to hot working.

Abstract: A method and apparatus are described for the casting of a composite metal ingot having two or more separately formed layers of one or more alloys. An open ended annular mould is provided having a divider wall dividing a feed end of the mould into at least two separate feed chambers. For each pair of adjacent feed chambers, a first alloy stream is fed through one of the pair of feed chambers into the mould and a second alloy stream is fed through another of the feed chambers. A self-supporting surface is generated on the surface of the first alloy stream and the second alloy stream is contacted with the first stream. By carefully selecting conditions and positions where the alloy streams meet, a composite metal ingot is formed in which the alloy layers are mutually attached with a substantially continuous metallurgical bond.

Abstract: A method of casting a metal ingot with a microstructure that facilitates further working, such as hot and cold rolling. The metal is cast in a direct chill casting mold, or the equivalent, that directs a spray of coolant liquid onto the outer surface of the ingot to achieve rapid cooling. The coolant is removed from the surface at a location where the emerging embryonic ingot is still not completely solid, such that the latent heat of solidification and the sensible heat of the molten core raises the temperature of the adjacent solid shell to a convergence temperature that is above a transition temperature for in-situ homogenization of the metal. A further conventional homogenization step is then not required. The invention also relates to the heat-treatment of such ingots prior to hot working.

Abstract: A method and apparatus is disclosed for casting metals in a DC mold to form an ingot or product having at least two layers formed by sequential solidification. The apparatus has at least one cooled divider wall at the entry end portion of the mold to divide the entry end portion into at least two feed chambers. Metal is fed to the chambers to form an inner layer and at least one outer layer. The divider wall has a metal-contacting surface for contacting the metal for the at least one outer layer, the surface being arranged at an angle sloping away from the metal for the outer layer in a downward direction. The angle is larger at the center of the divider wall compared to the angle adjacent to each longitudinal end thereof. The apparatus is suitable for co-casting metals having similar coefficients of contraction to minimize problems of adhesion between the layers of a resulting ingot or rolled products produced therefrom.

Abstract: A method and apparatus are described for the casting of a composite metal ingot having two or more separately formed layers of one or more alloys. An open ended annular mould is provided having a divider wall dividing a feed end of the mould into at least two separate feed chambers. For each pair of adjacent feed chambers, a first alloy stream is fed through one of the pair of feed chambers into the mould and a second alloy stream is fed through another of the feed chambers. A self-supporting surface is generated on the surface of the first alloy stream and the second alloy stream is contacted with the first stream. By carefully selecting conditions and positions where the alloy streams meet, a composite metal ingot is formed in which the alloy layers are mutually attached with a substantially continuous metallurgical bond.

Abstract: Apparatus and method of co-casting metal ingots in direct-chill casting apparatus. The apparatus and method employs at least one divider (divider member or divider wall) that separates a casting mold into two or more chambers for receiving molten metal that is combined into a single ingot. The divider may be moved, angled and/or flexed during casting to produce ingots that are designed primarily for rolling into thin plate or sheet. The ingot has at least one outer layer that is thicker adjacent to the side (width) edges than in the center, and/or thicker adjacent to the butt or head regions. This compensates for wiping of the outer layer from the ingot core during rolling. Also, the divider may be outwardly bowed outwardly towards one of the mold walls during the casting run.

Abstract: When a body of startup material has been interposed in the cavity between the starter block and a first cross sectional plane of the cavity transverse the axis thereof, the starter block has commenced reciprocating along the axis, and the body of startup material has commenced reciprocating in tandem with it, through a series of second cross sectional planes, layers of molten metal are successively superimposed on the body of startup material adjacent the first cross sectional plane of the cavity, and the layers promptly distend relatively peripherally outwardly from the axis under the inherent splaying forces therein. The invention confines the relatively peripheral outward distention of the layers with a casting surface which is peripherally outwardly flared about the axis of the cavity.

Abstract: When the starter block commences reciprocating along the axis of an open ended mold cavity, with a body of start up material in tandem with it, successive layers of molten metal are relatively superimposed on the body of start up material, and layers thereof are confined to a first cross sectional area of the cavity but permitted to distend relatively peripherally outwardly from the circumferential outline of the first cross sectional area at relatively peripherally outwardly inclined angles to the axis while thermal contraction forces are generated in the respective layers and the magnitude of the forces is controlled so that the thermal contraction forces counterbalance the splaying forces in the respective layers and confer a free-formed circumferential outline on the resulting body of metal as it becomes form-sustaining.

Abstract: When the starter block commences reciprocating along the axis of an open ended mold cavity, with a body of start up material in tandem with it, successive layers of molten metal are relatively superimposed on the body of start up material, and layers thereof are confined to a first cross sectional area of the cavity but permitted to distend relatively peripherally outwardly from the circumferential outline of the first cross sectional area at relatively peripherally outwardly inclined angles to the axis while thermal contraction forces are generated in the respective layers and the magnitude of the forces is controlled so that the thermal contraction forces counterbalance the splaying forces in the respective layers and confer a free-formed circumferential outline on the resulting body of metal as it becomes form-sustaining.

Abstract: The mold has a first chamber defined by a pair of inner and outer peripheral walls circumposed about the axis of the cavity and spaced apart from one another transverse the axis. The first chamber has oppositely disposed end walls that extend transverse the axis and an inlet for the supply of liquid coolant under pressure. The inner peripheral wall has a step which projects into the first chamber. The step has a first surface that extends transverse the axis and a second surface that extends parallel to the axis and coterminates with the first surface to form a corner. A second chamber is formed in the inner peripheral wall at the step. A series of holes open into the first chamber at one of the surfaces of the step to permit coolant to discharge into the second chamber at a reduced pressure. A passage opening discharges the reduced pressure coolant onto a body of metal emerging from the discharge end opening of the cavity.