Wagstaff, Inc.

Alcan International Limited

Wagstaff Engineering, Inc.

Robert B Wagstaff

David Alan Salee

Frank E Wagstaff

Richard J Collins

David A Fort

Hans Fischer

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. Initially, at the circumferential outline of the cross sectional area circumscribed by the surface in the first cross sectional plane of the cavity, the casting surface directs each of the layers into the series of second cross sectional planes at relatively peripherally outwardly inclined angles to the axis. Then the surface allows the layer to assume second cross sectional areas whose cross sectional dimensions undergo continual enlargement peripherally outwardly of the axis, so that the thermal contraction forces arising in the layer can counterbalance the splaying forces while the layer freeforms with the other layers into a body of metal at one of the second cross sectional planes of the cavity.

Casting of molten metal in an open ended mold cavity

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.

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.

Direct cooled annular mold

In direct cooling an ingot emerging from a mold, two sets 136 and 142 of liquid coolant streams are discharged onto the ingot from an annulus 62 circumposed about the lower end opening 72 of the mold. One set of streams, 136, is discharged downwardly at 22.5 degrees to the axis 12 of the mold, and the other, 142, is discharged downwardly at 45 degrees to the axis of the mold. The two sets are staggered to one another circumferentially of the mold, and because of the high angle of incidence of the 45 degree set to the axis of the mold, substantial portions of the 45 degree streams rebound from the surface of the ingot at their points 144 of impact with the ingot, and mushroom into corolla-like masses of air borne liquid coolant spray 146 lying crosswise the paths of the 22.5 degree streams, which in turn entrain the spray and impact the successive layers 138 of coolant therebelow with the spray. To aid in the entrainment, the respective streams are spaced apart from one another so closely that the respective pairs of adjacent corolla-like masses of spray actually shoot up 'interaction fountains' 148 of spray directly in the paths of the 22.5 degree streams of coolant. The effect is to widen the bands 135 of turbulence in the layers 138 of coolant; and the bands may even be widened to the extent of eliminating the laminar flow regime 137 in each layer. The height 133 of the bands is also commonly raised.

Direct cooled metal casting process and apparatus

The apparatus includes a first chamber disposed about the mold cavity and defined by a top, a bottom, and walls extending between the top and bottom at the inner and outer peripheries of the first chamber. A liquid coolant is supplied under pressure to the first chamber through an inlet. A step is formed adjacent one of the corners between the top and bottom .and the inner peripheral wall of the first chamber, a circumferential groove is formed in the outer peripheral wall of the step, and an elastomeric sealing ring is sealingly engaged with the mouth of the groove to define a second chamber in the groove. Meanwhile, the shoulder of the step is spaced apart from the other corner of the first chamber, and a series of holes is formed in the shoulder to permit the coolant to pass into the second chamber at a reduced pressure. A passage then discharges the reduced pressure coolant onto a body of metal emerging from the discharge end opening of the cavity.

Direct cooled metal casting apparatus

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. A graphite casting ring may be circumposed about the inner periphery of the case, to form a liner for the upper end portion of the cavity; and a refractory top ring may be circumposed about the upper end opening of the cavity, to form a hot top for the ring.

Annular metal casting unit

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. Where the liquid coolant discharge means take the form of a liquid coolant box, the housing 22, 24 of which defines the table, and the casting unit is upwardly inserted in the box, at an aperture 26 in the bottom, and abutted with the top of the chamber 14, a device 17 is provided for sensing leakage between the casting unit and the top of the chamber. The leakage is discharged in a passage 140 passing through one of the mullions to the bottom of the casting unit.

Metal casting unit

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. Pressurized gas is forced into the coolant flow through a body 72 of solid but porous, gas-permeable material that is incorporated into the wall 60 of the second passage at a surface thereof which extends generally parallel to the flow of coolant in the second passage. In this way, the coolant is amended to discharge through the first passage 14 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.

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Veradale, WA, United States of America

Robert B Wagstaff