Abstract: A method of removing heat from molten metal in which the metal is caused to flow freely within a gaseous media or vacuum over a body disposed within the metal stream such that any tendency for the metal to solidify during its passage is effective on the surface of said body against which the solidifying metal contracts into intimate contact therewith. The body may be forcibly cooled, e.g. by water. Accordingly, since the liquid metal is not enveloped by a channel or pipe, the solidifying shell tends to shrink on to the body, no gap is created, and this much higher heat transfer coefficients between the shell, the liquid metal, and the cooling body are achieved.

Abstract: In accordance with a new method of casting electrode grids for electric lead storage batteries in a mold, premature solidifying of the melt is prevented before the end of the mold filling period by an additional heating pulse applied to the melt during the mold filling process, as well as by the use of a good heat conducting mold material. The cooling down to the unmolding temperature is also accelerated. Because of the short dwell time of the lead within the mold, there simultaneously results a short machine cycling period. The separate pulse heating of the melt is preferably carried out by an induction heating apparatus, the alternating field of the inductor located within the mold walls producing heat through eddy current production within the molten molded body.

Abstract: A device for casting a metal in the pasty phase in a continuous casting mold comprises a vertical conduit disposed upstream of the mold and provided externally with cooling means a distributor member disposed substantially at the inlet of the conduit to deflect the metal flowing from a casting nozzle towards the inner surface of the vertical conduit which may be extended by a tubular element penetrating into the mold and an inlet section for the conduit at least the inner surface of which is formed by refractory material, the distributor member being disposed in the inlet section. The device may have an injector for injecting a gaseous agent into the vertical conduit below the distributor member, and a further device for causing the metal to rotate in the inlet section.

Abstract: Molten metal is poured in an open top basin that communicates via a sprue with a cavity or expendable pattern in a mold to fill the cavity and partially fill the basin. After the casting metal has solidified through the gating that connects the sprue to the cavity, a tapered heat transfer member is introduced into the molten metal in the basin. A cooling medium is passed through the heat transfer member to extract heat from the metal in the basin and correspondingly cool the metal casting, thereby decreasing the cooling period prior to shakeout.

Abstract: A method of forming a fine grained equiaxed casting by melting metal and removing most of the superheat of the molten metal. The molten metal is placed in a mold and optionally subjected to turbulence whereupon it solidifies to form the casting of the desired microstructure.

Abstract: A method of casting is provided in which a rheocast deposit is formed by atomizing a stream of molten metal or metal alloy by subjecting the stream of molten metal or metal alloy to relatively cold gas directed at the stream, and directing the resultant spray of metal droplets at a collector. The deposit is provided with a rheocast type structure by extracting heat from the metal droplets such that the material deposited at the collector includes solid phase particles in a liquid phase which, upon solidification, forms a microstructure characterized by a fine network of microsegregate at the grain boundaries or coring across the grains and which, above the solidus region of the said metal or metal alloy, exhibits thixotropic properties. The rheocast deposit may be thixotropically deformed either during or after deposition.

Abstract: A static casting method for a hollow cast product using a mold with bottom comprising a top lid, a core and an outer mold section, the core being attached to the top lid and disposed inside the outer mold section. The outer mold section includes a lateral mold section and a lower mold section. The lateral mold section is formed at its inner peripheral wall portion with a composite cooling section by stacking chiller blocks and interposing therebetween refractory sands and at its outer wall portion with refractory sands. Cooling pipes include first and second pipes. A first pipe extends longitudinally through the refractory sands at the outer wall portion and a second pipe extends longitudinally through the inner wall portion in contact with at least a part of each of the chiller blocks, the first and second pipes being connected at their lower portions through the bend portion. The chiller blocks are cooled by water flowing in the second pipes. The entire casting cavity is first filled with molten metal.

Abstract: In order to obtain a desired metal structure in a metal or alloy part having discontinuous portions, the metal or alloy part to be treated is inserted into a mold having a simple outer surface configuration. Thereafter the metal or alloy part to be treated is heated together with the mold.

Abstract: The .alpha.-stabilizing element, e.g. P, and the .gamma.-stabilizing element, e.g. Mn, do not segregate at an identical site of a casting. Castings are cooled at a rate of 40.degree. C./min or less in a temperature range of the peritectic reaction and/or the Ar.sub.4 transformation, thereby condensing P and Mn into .delta. and .gamma. phases, respectively.

Abstract: A method of forming a fine grained equiaxed ingot by melting metal and placing it in a mold having a restriction at the entrance disposed to solidify the metal in the entrance to the mold prior to complete solidification of the metal in the mold such that a shrinkage void is formed below the entrance to the mold. The ingot is then hot isostatically pressed (HIPped) to fully densify the ingot and eliminate the shrinkage void.

Abstract: The invention provides an arrangement for producing solid metal with fine solidification structure from liquid metal including the steps of transferring liquid metal with a minimum flow through a hollow carrier; the minimum bulk velocity of the metal through the carrier being 50 cm/sec.

Abstract: An improved mold includes an upper mold section having a primary distribution system which is connected with a furnace and a lower mold section which is withdrawn from the furnace on a chill plate. A baffle plate is supported from the primary distribution system. The lower mold section includes a secondary distribution system which is connected in fluid communication with the primary distribution system at separable joints. The secondary distribution system is connected in fluid communication with article molds which are disposed in an annular array. During pouring of molten metal, reaction forces are transmitted to the chill plate from the pour cup through a support post and baffle plate. Once the article molds have been filled with molten metal, the chill plate is lowered. The primary distribution system which is connected to the furnace, remains stationary.

Abstract: This invention relates to cast iron and more particularly to the improvement in the toughness and abrasive resistance of white cast iron along with a significant increase in tensile strength. More specifically, the present invention relates to a new white cast iron composition and a process for producing such cast iron having improved toughness, ductility and tensile strength while retaining desirable abrasive resistance through modification of the carbide morphology.

Abstract: A process for casting molten metallic material having a solidification ra of temperatures, especially alloys containing more than 80% aluminium, involves simultaneously stirring and cooling the molten material to a temperature between 0.degree. C. and 75.degree. C. above the liquidus temperature of the metallic material using hollow heat transfer rods (9) extending across a duct (4), down which the material is caused to flow. The material is then caused to solidify with a substantially non-dendritic microstructure by rapidly cooling it in a continuous casting machine. The solidified bar so produced may then be reheated at a steady rate to a point between its liquidus and solidus temperature until it contains between 30% and 70% by volume solids content but can still be maneuvered without losing its shape. It may then, with a minimum of delay, be rapidly formed into a solid article of any desired shape by, for example, casting in a pressure casting machine.

Abstract: An apparatus is provided for electromagnetically coiling a molten material into a longitudinally extending casting defining a longitudinal axis thereof. The casting has a desired cross section extending perpendicular to the longitudinal axis. At least one portion of the outer peripheral surface of the casting extends transversely of the longitudinal axis and has a small radius of curvature. The apparatus includes an inductor extending transversely about the molten material for providing an electromagnetic containment force field acting on the outer peripheral surface of the molten material to form the desired cross section. The improvement comprises a device for turning the electromagnetic containment force field about the longitudinal axis to cause a corresponding turn of the transverse cross section of the molten material about the longitudinal axis.

Abstract: An improved method of casting an article decreases the time required to cast the article without affecting the quality of the article. When a directionally solidified (DS) casting is made, molten metal is poured into a mold cavity. One end of the mold cavity is exposed to a chill plate which initiates solidification of the molten metal. As the metal solidifies, a dendritic structure grows upwardly into the mold cavity. Molten metal is disposed in the interstices of the uppermost portions of dendritic structure. As the metal in the mold cavity cools, the molten metal in the interstices solidifies and the dendritic structure, including a region containing some molten metal in the interstices, continues to grow upwardly toward the upper end of the mold cavity. The directional solidification of the metal in the mold cavity is promoted by slowly withdrawing the mold from a furnace as the molten metal solidifies.

Abstract: A molten metal treatment apparatus comprising a passage of predetermined size and length for receiving superheated molten metal from a source thereof, and for supplying the molten metal for subsequent casting; a gas inlet and a control valve for controlling the velocity of the molten metal through the passage by exposing the molten metal to a source of pressurized gas; a cooling jacket at least partially surrounding the passage for controlling the temperature of the molten metal within the passage between predetermined upper and lower limits for forming a thin solidified shell having a molten metal core within the passage; the combination of the velocity of molten metal and the temperature of the molten metal within the passage for allowing dendrites to grow into the molten core from the solidified shell, and for breaking off portions of the dendrites and entraining them in the molten metal thereby producing a solids content within the molten metal for subsequent casting.

Abstract: A process for preparing a slurry structured metal composition comprising degenerate dendritic solid particles contained within a lower melting matrix composition, the process comprising vigorously agitating at a given shear rate molten metal as it is solidified. Greatly improved processing efficiencies result if the shear and solidification rates are adjusted so that the ratio of the shear rate to the solidification rate is maintained at a value ranging from 2.times.10.sup.3 to 8.times.10.sup.3.

Abstract: Method and apparatus for producing a fine-grain ingot are disclosed. A feedstock stick is melted to produce a series of fully molten drops which falls on the upper surface of an ingot being formed, to cover a portion thereof which is substantially less than the ingot's total upper surface. The mold is moved laterally with respect to the feedstock stick at a rate which is high enough so that the molten metal impinges upon different portions of the ingot's upper surface but which is low enough to prevent a substantial centrifugally outward flow of the metal impinging on the upper surface of the ingot. The molten metal melt rate is so selected that the impact region on the ingot's upper surface is at or below the solidus temperature of the alloy and above a temperature at which metallurgical bonding with the successive impinging metal can occur.

Abstract: A process for casting a material comprising a coolant application device comprising a fluidized bed cooling system. A control system for the fluidized bed cooling system determines the most upstream position at which the fluidized bed contacts the material being cast. The control system is adapted to adjust the pressure differential between the gas used to fluidized the bed of particles and an opposing gas flow. The casting system may be a continuous or semi-continuous one and preferably employs an electromagnetic mold.

Abstract: A mold structure for casting large metallic parts such as ingots so as to avoid the formation of the "shrinkage pipe" which normally develops on the exposed top surface of such castings during their solidification comprises a cap for placement on a mold which includes a diaphragm having a front surface located to intercept radiation emitted from the top surface of the cooling metal mass and to re-emit radiation back thereto, and a reflector for returning radiation emitted from the back surface of the diaphragm such as an infrared reflector or a stack of baffles. The cap may include a cooler for cooling the reflective surface and suitable ports which allow the interior of the mold and cap to be evacuated. Portions of the mold adjacent its open top may be provided with insulation to prevent heat loss from the metal by conduction. A heater for providing make-up heat to the top surface of the metal mass may also be included in the structure.

Abstract: The present invention provides a new and improved method of making an improved turbine engine component having an annular array of airfoils connected wth inner and outer shrouds. The airfoils are cast separately from the shrouds to enable the airfoils and shrouds to be made from either the same or different materials. The airfoils advantageously have an elongated columnar grain structure with grain boundaries extending parallel to the leading and trailing edges of the airfoils. The inner and outer shrouds are formed of a plurality of arcuate sections which also may have an elongated columnar grain structure. The ends of the arcuate shroud sections are interconnected in such an orientation that the grain boundaries extend circumferentially around the circular shrouds to minimize the extent to which ends of the grains are exposed. In another embodiment of the invention, each of the arcuate shroud sections is formed of a single crystal.

Abstract: In a method for forming shaped articles from molten metallic material the melt is caused to flow from a holding vessel therefor through a refractory duct having at least one static thermally-conducting element extending transversely within the duct so dimensioned and located to both cool and stir by shear the melt flowing therethrough. The melt is cooled to a temperature within its freezing range, if it is an alloy, or at its freezing point, if it is a metal, and is stirred to precipitate a solid phase as fragmented dendrites. The cooled and stirred metal outflow from the duct is cast into shaped articles. The invention has one specific application in producing the precipitating solid phase as non-degenerate micro-crystalline particles.

Abstract: In the manufacturing of a shell for a cast iron rolling mill roll, heating the chill prior to casting so that the chill at the time pouring commences is in the approximate range of 300.degree. to 600.degree. F. in order to decrease the cooling rate of the metal after it passes through the solidus at a rate slower than normal to allow sufficient time through a critical temperature zone for the super-saturated solution to precipitate complex compounds in the solid solution phase. The present invention relates to a high alloy metal chemistry such as employed in the manufacture of a high chromium shell for a rolling mill roll whereby after solidification the cooling rate is decreased and controlled to allow a sufficient time through a critical temperature zone for the super-saturated solution to precipitate complex compounds in the solid solution phase.

Abstract: Production of boron-containing steel slabs free from surface defects by continuous casting, particularly prevention of the slab surface crackings by cooling the slab with a specific cooling rate through the temperature range from the melting point to 900.degree. C. so as to prevent boron-containing compounds such as BN from precipitating along the austenite grain boundary. Great advantage over the conventional art is that boron-containing molten steels which could not be continuously cast can be successfully continuously cast into slabs free from surface defects.

Abstract: Die castings are made from metal compositions that are fully liquid or as a preferred embodiment contain between about 10 and 85 weight percent degenerate dendrites. The composition is injected into the cavity of a die at a mean die temperature which is as near to ambient temperature as possible and usually less than about 400.degree. F. The die is formed of a material having a thermal diffusivity of at least about 0.5 cm.sup.2 /sec. The castings are ejected and the die surface is sprayed with a liquid to bring the die surface temperature back to the mean die temperature or below in the shortest possible time. The time between injection and ejection is less than about 1 minute and the time between ejection and spraying is less than about 30 seconds.

Abstract: A metal casting system including novel process and apparatus wherein the shape of the casting is defined by a thin thermal degrading film supported by a particulate bed. A pattern having the shape of the desired casting is surrounded by the tight fitting film with one end of the pattern exposed. A particulate bed is tightly packed about the film-surrounded pattern. A reduced fluid pressure is established within the particulate bed relative to the pattern so that the surrounding film is tightly held by atmospheric pressure against the particulate bed and slightly released from the pattern. The pattern is removed from the surrounding film and leaves therein a cavity bounded by the film with the shape of the desired casting. The cavity is filled with molten metal for forming the desired casting simultaneously with the vaporization of the film. The present metal casting system is especially useful for the casting of cylindrical shapes using unique molds and a novel flask is provided for such a casting process.

Abstract: A process for forming metal compositions containing in situ composites. A metal composition is heated to a liquid and then solidified by being directed into a cooling zone. The metal in the small volume at or near the liquid-solid interface is heated to achieve a high temperature gradient between the solid and liquid metal while not exceeding an average temperature in the liquid which degrades the container for the liquid metal. The metal fed into the small volume can be either a liquid or a solid.

Abstract: Energy efficient reheating furnaces and soaking pits having essentially zero thermal inertia are disclosed.The furnace comprises an evacuate chamber having a workpiece support, an envelope having a highly infrared reflective interior surface bounding the chamber, and a workpiece heating means comprising electric leads and contacts for heating the workpiece by electrical resistance and/or a cryogenically cooled induction coil located outside of the envelope for heating the workpiece by eddy current dissipation. A workpiece on the support is thermally isolated since convective heat losses are eliminated, conductive heat losses minimized, and radiative heat losses limited to about 10 percent or less of the workpiece's black body radiative flux. Since radiation emitted by the workpiece does not reach the induction coil, the design allows the application of cryogenic-superconductivity technology which eliminates eddy current losses in the coil.

Abstract: A mold for casting metals is provided with a roughened surface so that, on first contact of the mold with the melt, heat transfer is controlled in such a way that the melt comes into contact only with the peaks of the projections on the mold surface and an air gap is formed between the melt and the valleys on the surface. The pattern of roughness on the mold surface comprises a uniform arrangement of pyramidal or blunted-cone shaped projections. Neighboring projections are spaced a distance d of 0.05 to 1 mm apart and have a height h of 0.1d<h<d. The pyramid or blunted con surfaces satisfy the condition of 0.05<.function./d.sup.2 <0.5. A process which does not involve deformation is preferred for producing the rough pattern, for example, a photochemical etching process. The molds are suitable for many casting processes, in particular for continuous D.C. ingot or strip casting with moving molds and caterpillar track type mold belts.

Abstract: A segmented mold assembly is utilized to cast a turbine engine component having a relatively heavy hub from which relatively light vanes project. The mold assembly includes a plurality of sections which are formed of a ceramic mold material and are interconnected at flange joints. The mold sections are advantageously formed by repetitively dipping patterns in a slurry of liquid ceramic mold material to form wet coatings on the patterns. These wet coatings are dried and separated from the patterns to form the mold sections. The mold sections which are used to cast the vanes retard the removal of heat from the vanes to provide time for the hub to solidify. This can be accomplished by using relatively thick walled mold sections to form the mold cavities in which vanes are cast and relatively thin walled mold sections to form the cavity in which the hub is cast.

Abstract: A method of continuously casting metal ingots is provided comprising the steps of introducing molten metal into an open-ended mold, applying a liquid cooling medium to the mold to effectuate at least partial solidication of the molten metal in the mold and advancing an ingot from the mold, with the ingot having the peripheral portion, at least, solidifed while applying liquid cooling medium to the exterior surface of the emerging ingot. The improvement of the present invention comprises retarding the cooling effect of the liquid cooling medium by mixing a gas with the medium to be applied to the ingot surface prior to application of the medium to the ingot surface, whereupon the gas forms a layer of gaseous insulation between the medium and the ingot surface upon application of the medium to the ingot surface.

Abstract: Tubular metal articles are produced by centrifugal casting in a rotary metal mold lined by centrifugally distributing a quantity of a dry finely particulate free flowing refractory material on the active mold surface with the quantity being in excess of that required for the lining, densifying the layer by rotating the mold at a rate such that the refractory layer is subjected to centrifugal force adequate to establish an equivalent specific gravity of at least 7.5, determined by multiplying the actual specific gravity of the refractory material by the number of gravities of centrifugal force, contouring the densified layer and removing the excess refractory material, rotating the mold at the casting rate and then introducing the molten metal for casting while continuing to rotate the mold at least that rate. Articles so cast have relatively smooth outer surfaces which require only finish machining.

Abstract: Method and apparatus for casting a metal article in a mold at least as long as the article, utilizing a cooled mold of elongated form having top and bottom portions. The method includes the steps of introducing molten metal from a source through the bottom portion of the mold, flowing molten metal into the mold so as to form a solidifying casting shell which during casting occupies at least 40% of the cross-sectional mold area and has a molten core, and flowing molten metal from the source through the core towards the mold top.

Abstract: A mould assembly for casting molten metal which comprises a book mould, the upper parts of the walls of the upwardly open cavity of which are lined with hot top lining material and wherein extending across the width of the cavity there are one or more bridges of hot top lining material maintaining the hop top lining material along the longer walls of the cavity in contact with those longer walls.

Abstract: In the production of aluminum ingots by the direct chill casting process, in which the conventional chilled mold is equipped with a thermally insulated "hot top," smooth surfaced ingots are produced under conditions obtained by correlating of the length of the chilled mold, the casting rate and the head of molten metal in the hot top. Preferably the values of chilled mold length and metalostatic head are selected so as to be tolerant of some variation of metalostatic head which is difficult to avoid in the simultaneous operation of a large number of molds under level pour conditions.

Abstract: This process for manufacturing spheroidal graphite cast iron pipes by centrifugal casting has the feature that the rate of the cooling of the liquid iron just centrifugally cast in a tubular layer is increased from a zone of the layer spaced away from the mould to the free inner surface of this tubular layer while the cooling of the liquid iron in the vicinity of the surface of the mould is slowed down.

Abstract: A method of producing castings comprising the steps of: pouring moulds with inoculated cast iron containing, by weight per cent: carbon 3.6-3.8, silicon 2.8-3.2, manganese up to 0.4, magnesium not more than 0.01, at a melt temperature ranging from 1420.degree. to 1450.degree. C, and subsequently cooling the cast iron. The thickness of walls of the castings is chosen so that the initial cooling rate is 10.degree.-14.degree. C/sec with a preset heat conductivity.

Abstract: A metallic alloy is cast in a mold to produce a solid body by unidirectional solidification. The alloy, initially in a molten state, is cast into a mold and is completely and progressively cooled in the mold while a unidirectional thermal gradient superimposed thereon parallel to a direction determined by the configuration of the mold (predetermined direction) until a metastable equilibrium is reached in which the entire body of the melt is in a super-cooled state as a homogeneous liquid. The equilibrium is then broken to cause solidification of the alloy and the formation of dendritic crystals with their principal axes parallel to the thermal gradient substantially instantly and without noticeable advance of a solidification front across the melt.

Abstract: The mold is preheated to a temperature above the maximum local casting temperature prior to casting of the melt and is also cooled to obtain a variation of temperatures throughout the mold. The resulting temperature gradient of the mold is intended to maintain the heat content per unit volume in the unsolidified melt portions greater than in the adjacent solidified melt portions to compensate for the latent heat of solidification in the melt and thus avoid shrinkholes and blowholes.

Abstract: A method for casting steel ingots in molds is provided wherein the upper surface of the ingot is caused to solidify before the interior of the ingot is solidified in order to provide an improved ingot having sound and homogeneous material over all the surfaces of the ingot and a good distribution of segregates throughout the cross section of the ingot. In the improved method, the surface temperature of the upper surface of the ingots is maintained at or near the liquidus temperature of the steel being casted for at least 10 seconds after casting so that the upper surface of the ingot remains fluid to allow slag inclusions to float to the upper surface of the ingot. The upper surface of the ingot is then solidified between 10 seconds and 2 minutes after casting by lowering the surface temperature of the ingot to a temperature at or near the solidus temperature of the steel so that the upper surface of the ingot solidifies before the interior of the ingot is solidified.

Abstract: A method of manufacturing a brake drum having a plurality of axially spaced, circumferentially extending ribs provided on the exterior surface thereof. The method includes casting molten grey iron into a mold cavity formed by a plurality of axially split external mold segments spaced radially outward from an internal mold member, spacing the radially inward portions of the interfacing lateral edge surfaces of the external mold segments to form a flash base free of white iron metal at the parting line between adjacent external mold segments and, after cooling the molten iron and removing the mold members, grinding away at least a portion of the flash metal formed between the interfacing lateral edge surfaces of the external mold segments radially outward of the flash base to provide an axially extending ridge free of white iron and traversing the axially spaced ribs.

Abstract: Aluminum is produced from low-grade aluminum alloys by melting an Al-X alloy wherein X has a higher specific weight than aluminum and forms an eutectic mixture rich in aluminum, the starting melt being on the side of the eutectic mixture rich in aluminum, and radially cooling the melt from the inside to the outside while under the effect of centrifugal force.

Abstract: A method of making a more economical and reliable treating agent for use in late metal treatment when pouring metal castings. The treating agent is defined as an essentially homogeneous solid cast block preferably containing alloying ingredients to nodulize or inoculant ferrous metal. Each block is designed to present a generally uniform reaction surface to molten metal to be treated. This is obtained by casting the block to a shape which snugly fits a prepared basin in the mold gating system over which the molten metal to be treated must flow, or to cast the block in an annular configuration through which the molten metal must flow. The latter block has contoured inner surfaces which maintain a generally constant reactive surface as the block is consumed. These blocks are preferably prepared by simultaneously casting a large number in closely nested relation.

Abstract: A method of manufacturing a cast ferrous metal die wherein an initial die of non-ferrous metal is cast in a mould against a basic metal pattern having a melting point substantially not less than that of the non-ferrous casting metal, the basic metal pattern being preheated and coated with refractory material and the non-ferrous casting metal is cast against the preheated and coated basic pattern in a supercooled condition to minimise thermal shock and heat transference between the casting metal and basic pattern, and forming a further corresponding pattern of refractory material in the initial die, and then using the pattern of refractory material in a mould for casting a cast ferrous metal die from said refractory pattern, the cast ferrous metal die so obtained being of corresponding accuracy to the basic metal pattern.

Abstract: Method and apparatus for casting a metal article in a mold at least as long as the article, utilizing a cooled mold of elongated form having top and bottom portions. The method includes the steps of introducing molten metal from a source through the bottom portion of the mold, flowing molten metal into the mold so as to form a solidifying casting shell which .Iadd.a .Iaddend.during casting occupies at least 40% of the cross-sectional mold area and .Iadd.a .Iaddend.has a molten core, and flowing molten metal from the source through the core towards the mold top .Iadd.at a filling rate, dependent on the mold cross sectional area, such that the product produced will have a relatively fine grained structure throughout the cross-section thereof.Iaddend..

Abstract: Tubular metal articles are produced by centrifugal casting in a rotary metal mold lined by centrifugally distributing a quantity of a dry finely particulate free flowing refractory material on the active mold surface with the quantity being in excess of that required for the lining, densifying the layer by rotating the mold at a rate such that the refractory layer is subjected to centrifugal force adequate to establish an equivalent specific gravity of at least 7.5, determined by multiplying the actual specific gravity of the refractory material by the number of gravities of centrifugal force, contouring the densified layer and removing the excess refractory material, rotating the mold at the casting rate and then introducing the molten metal for casting while continuing to rotate the mold at least that rate. Articles so cast have relatively smooth outer surfaces which require only finish machining.