Abstract: As a reversal of previous practice, the annular body of the mold in the unit has an annular case at the bottom thereof, rather than at the top thereof. The case is relatively thick axially of the mold, so as to form the greater portion of the axial length of the mold body at the outer periphery thereof; and at the top thereof, the case has an annular plate thereon, which forms a pair of flanges that overhang the case and enable the metal casting unit to be lowered into an aperture of a casting table from above, and supported on top of the table at the flanges. Meanwhile, the case defines the lower end opening of the mold cavity, and the outlet for liquid coolant that is discharged onto the molten metal body as it emerges from the unit. Commonly, the case is monolithic, and also has an annular sump at the top thereof which is covered by the plate to form a chamber for the coolant in the sump.

Abstract: A casting unit 6 consists of a monolithic body which is annular in shape and has an annular flange 72 outturned about the axis and monolithically outstanding on the body at the outer periphery, a set of lugs 110 angularly spaced about the axis on the lower end portion of the body and monolithically outstanding in the aperture, and a circumferential groove 114 about the outer periphery of the body in the upper end portion, with mullions 20 monolithically upstanding therein, adjacent the outer periphery of the groove, to form ports 112.The groove is interconnected with the cavity 108 in the lower end portion of the body at the aperture; and passages, 126, 140, a graphite ring 16, and whatever else is required, are added to complete the unit 6 before it is supported in an aperture in a metal casting table 2, having liquid coolant discharge means 14 circumposed thereabout and a stool to support molten metal after being mated with the lugs.

Abstract: A body of partially solidified metal emerging as ingot from the exit end 10 of an open ended mold 2, is direct cooled by charging liquid coolant into an annular retention chamber 32 circumposed about the exit end opening of the mold in the body thereof, and discharging the coolant from the chamber onto the surface of the ingot through a first passage 14 opening into the exit end of the mold and communicating with the chamber at an opening 50 therein. At times, such as in the butt-forming stage, a second passage 46 is formed in the chamber which is serially interconnected with the first passage 14 at the chamber opening 50 and operable to deliver the chamber coolant to the first passage at an increased rate of flow, relative to the rate at which the coolant was charged into the chamber.

Abstract: A body of partially solidified metal emerging as ingot from the exit end of an open-ended mold, is direct cooled by discharging liquid coolant onto the surface of the ingot through a passage of the mold opening into the exit end of the mold at an aperture therein; and at times, such as in the butt-forming stage, by the added step of forcing pressurized gas into the coolant through a body of solid but porous, gas-permeable material incorporated into the wall of the passage at a surface thereof which extends generally parallel to the flow of coolant in the passage and coterminates with the exit end of the mold at the aperture to form an edge thereof. When the gas is added, the coolant discharges through the aperture in a discontinuous liquid phase in which it is laden with bubbles of undissolved gas that will alter the heat transfer characteristics of the coolant on the surface of the ingot to vary the rate at which heat is lost therefrom.

Abstract: The mold is equipped with a casting ring 6 which is formed by clamping together four generally rectilinear wall segments 8 that are, first, arranged like the sides of a picture frame about the rabbet 52 of a rectangular case 10, and then abutted together, sash-like, at their mitered ends 80, to form a ring, the casting surface 9 of which will produce the rectangular cross-sectional outline common to sheet ingot or the like, when molten metal is fed through the ring. The clamping action is produced by a set of screws 94 at the corners 10' of the case, and after the ring 6 is clamped about a pair of spaced, axially opposing lips 54 and 60 on the case and an annular plate 14 thereabove, the plate 14 is clamped to the top of the case, to secure the ring in place and seal the axial ends of the ring against fluid flow thereacross.

Abstract: Close control of the direct cooling rate is achieved by bubbling a substantially insoluble gas into the curtain-forming coolant as it is about to discharge onto the emerging ingot. The resulting bubble-entrained curtain of coolant experiences an increased velocity, and the increase is not accompanied by a reduction in the thermal conductivity of the coolant. Instead, the bubble-entrained coolant appears to have a scrubbing effect on the metal, which breaks up any film and reduces the tendency for film boiling to occur at the surface of the metal, thus allowing the process to operate at the more desirable level of nucleate boiling, if desired. This in turn makes it possible to regulate the cooling rate by selective use of the bubbling effect, including turning the effect on and off to allow film boiling to occur when desired, such as in the butt forming stage of the casting operation.

Abstract: One end opening of an open ended mold cavity has a diameter smaller than the peripheral wall of the cavity and a molten metal mass is introduced to the cavity by continuously filling the one end opening with the mass so that the molten metal splays about the inner peripheral edge of the opening to assume a cross-section between the ends of the cavity having a divergent/convergent outline, the intermediate continuum of which between the planes of maximum divergence and minimum convergence thereof, has a peripheral outline corresponding generally to the outline of the cavity at the peripheral wall thereof. A graphite or graphite-like ring is circumposed about the axis of the cavity in the peripheral wall thereof to form a solid but fluid permeable wall section that is disposed to define the peripheral outline of the intermediate continuum of the metallic mass.

Abstract: One or more top-opening mold cavity defining members are supported in the chamber of a coolant box adapted for the flow of liquid coolant therethrough about the members. Each member is supported in a telescoping assembly in which the top opening of the member is co-axial with an opening in the top of the chamber to enable molten metal to be introduced to the cavity of the member through the respective top openings of the chamber and the member. Moreover, each member has a greater outer peripheral diameter transverse the axis than the top opening of the chamber, and is engaged with the top of the chamber about the opening thereof in a first horizontal plane of the box. The member is also engaged with the defining surfaces of the chamber in a second horizontal plane of the box spaced below the aforesaid first horizontal plane of the box by a vertical gap.

Abstract: The mold comprises a generally rectangularly shaped, machine duplicatable band which is monolithically circumferentially continuous and inherently convexly bowed on the relatively longer and shorter sides thereof, so that it forms crowns on the opposing side walls of the ingot operatively formed therein. The bow in the relatively longer sides of the band has an inherent deflection adapted to form a crown intermediate between that adapted to compensate for shrinkage during the butt forming stage of the casting operation, and that adapted to compensate for shrinkage when the casting operation is conducted at operating speed.