Abstract: Certain embodiments of a melting and casting apparatus comprising includes a melting hearth; a refining hearth fluidly communicating with the melting hearth; a receiving receptacle fluidly communicating with the refining hearth, the receiving receptacle including a first outflow region defining a first molten material pathway, and a second outflow region defining a second molten material pathway; and at least one melting power source oriented to direct energy toward the receiving receptacle and regulate a direction of flow of molten material along the first molten material pathway and the second molten material pathway. Methods for casting a metallic material also are disclosed.

Abstract: Disclosed is a continuous rapid solidification apparatus, which includes a cooling roll configured to cool a molten metal supplied to an outer circumference surface thereof; a crucible configured to supply the cooling roll with the molten metal; and two or more molten metal supplies configured to melt raw material metal and alternately supply the crucible with the molten metal.

Abstract: A method and a device for producing ingots from metal or metal alloy. The method and the device are suitable for producing ingots from nickel, titanium, vanadium, niobium, tantalum, zirconium, hafnium, or alloys thereof and alloys of the metals in continuous casting methods. The device has an ingot chamber, which is suitable for receiving multiple cast ingots and for allowing the ingots to cool in the ingot chamber. For this purpose, the ingots are arranged in the ingot chamber in a horizontally movable manner on ingot tube section.

Abstract: A method of operating an electric arc furnace containing a furnace shell having a tapping hole, a plurality of electrodes, and a rotating apparatus that rotates the furnace shell around a vertical axis relative to the electrodes, the method contains a charging step of opening an opening-and-closing door of a scrap bucket containing a metal material and falling the metal material into the furnace shell in which the furnace shell is rotated by the rotating apparatus until a direction of a line connecting a center of the furnace shell to a center of the tapping hole intersects an extension direction of a seam at a closing side of the opening-and-closing door, the opening-and-closing door is opened in this positional relationship to charge the metal material.

Abstract: A method for continuous thin strip casting comprises: introducing molten steel through a long nozzle into a tundish from a ladle, the tundish is one strand tundish, and the molten steel flows below a weir, then passes a first dam and enters a channel with an induction heating device, and the heated molten steel then flows out from an outlet at the other side of the tundish to a nozzle also with an induction heating device for casting. The distances between the weirs of the tundish and the channel have optimal distance ranges. The present invention can improve the casting stability and the quality of the casting strip.

Abstract: Provided are a method and apparatus for refining titanium scraps and sponge titanium, which can remove oxygen from a melt by supplying a deoxidizing gas to the surface of the melt in order to refine titanium scraps and sponge titanium. The method for refining titanium scraps and sponge titanium comprises supplying hydrogen ions and electrons in plasma to a titanium melt to remove oxygen from the titanium melt surface having an oxide layer formed thereon. In addition, the apparatus comprises: a vacuum chamber; a crucible located in the vacuum chamber and configured to perform melting by the magnetic field of an induction coil in a state in which a melt and the inner wall of the crucible; a calcium gas supply means configured to supply calcium gas from the bottom of the crucible to the space between the inner wall of the crucible and the melt.

Abstract: An article composed of sintered particles is produced by depositing ligand-containing particles on a substrate, then scanning the substrate with an electron beam that generates sufficient surface and subsurface heating to substantially eliminate the ligands and melt or sinter the particles into a cohesive film with superior charge carrier properties. The particles are sintered or melted together to form a polycrystalline layer that is substantially ligand-free to form, for example, a film such as a continuous polycrystalline film. The scanning operation is conducted so as to heat treat a controllably localized region at and below a surface of the particles by selecting a rate of deposited energy at the region to exceed a rate of conduction away from the substrate.

Abstract: Provided is a method for producing a platinum group-based alloy capable of producing a sound molten ingot of a platinum group-based alloy in a large amount.

Abstract: Provided is a device for titanium continuous casting (1) capable, even when continuously casting large diameter titanium ingots or titanium alloy ingots, of suppressing component segregation thereof. The device for titanium continuous casting (1) comprises: a mold (3) having an upper section having a circular upper opening (3a) for pouring in molten metal (6), and a bottom section having a lower opening for continuously drawing ingots (11); and a plurality of plasma torches (4, 5) to heat the molten metal in the mold (3) from the upper opening (3a) side. The plurality of plasma torches (4, 5) are disposed so that the amount of heat input to the molten metal (6) present in the outer circumference enclosing the center of the upper opening (3a) is greater than the amount of heat input to the molten metal (6) present in the center of the upper opening (3a).

Abstract: A casting system and method. The casting system can include an energy source and a hearth, which can have a tapered cavity. The tapered cavity can have a first end portion and a second end portion, and the tapered cavity can narrow between the first and second end portions. Further, the tapered cavity can have an inlet at the first end portion that defines an inlet capacity, and one or more outlets at the second end portion that define an outlet capacity. Where the cavity has a single outlet, the outlet capacity can be less than the inlet capacity. Where the cavity has multiple outlets, the combined outlet capacity can match the inlet capacity. Further, the cross-sectional area of the tapered cavity near the inlet can be similar to the cross-sectional area of the inlet.

Abstract: A casting system and method. The casting system can include an energy source and a hearth, which can have a tapered cavity. The tapered cavity can have a first end portion and a second end portion, and the tapered cavity can narrow between the first and second end portions. Further, the tapered cavity can have an inlet at the first end portion that defines an inlet capacity, and one or more outlets at the second end portion that define an outlet capacity. Where the cavity has a single outlet, the outlet capacity can be less than the inlet capacity. Where the cavity has multiple outlets, the combined outlet capacity can match the inlet capacity. Further, the cross-sectional area of the tapered cavity near the inlet can be similar to the cross-sectional area of the inlet.

Abstract: A system for applying a target track material to an x-ray tube target includes a controller configured to direct a beam of energy toward an x-ray tube target, and direct a solid stock material toward the beam of energy to cause the solid stock material to melt and deposit as a melted material on the x-ray tube target.

Abstract: A casting system and method. The casting system can include an energy source and a hearth, which can have a tapered cavity. The tapered cavity can have a first end portion and a second end portion, and the tapered cavity can narrow between the first and second end portions. Further, the tapered cavity can have an inlet at the first end portion that defines an inlet capacity, and one or more outlets at the second end portion that define an outlet capacity. Where the cavity has a single outlet, the outlet capacity can be less than the inlet capacity. Where the cavity has multiple outlets, the combined outlet capacity can match the inlet capacity. Further, the cross-sectional area of the tapered cavity near the inlet can be similar to the cross-sectional area of the inlet.

Abstract: The continuous casting device according to the present invention enables at least some of a plurality of hearths (3) to be converted between being hearths (13) used for titanium, which are used during the continuous casting of titanium ingots, and being hearths (23) used for titanium alloy, which are used during the continuous casting of titanium alloy ingots. The number of hearths (23) used for titanium alloy is greater than the number of hearths (13) used for titanium. Also, the total capacity of the hearths (23) used for titanium alloy is greater than the total capacity of the hearths (13) used for titanium. Thus, titanium ingots and titanium alloy ingots can each be continuously cast by means of a single piece of equipment.

Abstract: The present invention is a method for manufacturing a titanium ingot (30), the method being characterized by comprising: a step of melting a titanium alloy for a predetermined time by cold crucible induction melting (CCIM); a step of supplying molten titanium (6) to a cold hearth (10), and separating high density inclusions (HDIs)(8) by precipitation in the cold hearth (10) while spraying a plasma jet or an electron beam onto the bath surface of the molten titanium (6); and a step of supplying a molten titanium starting material from which the HDIs (8) are separated by precipitation to a mold (20) to obtain the titanium ingot.

Abstract: A system and method for producing a metallic ingot using, for example, a VAR furnace, includes a primary crucible receiving a melted metal from a source of metal and collecting the melted metal to for a pool of melted metal, the primary crucible including an overflow lip, a secondary crucible receiving the melted metal from the overflow lip of the primary crucible, the secondary crucible being smaller than and electrically isolated from the primary crucible, and a withdrawal device withdrawing the molten metal, solidified by cooling, from the secondary crucible in the form of solidified ingots, wherein the solidified ingots have a smaller diameter than a diameter of the source of metal. A cutting device periodically cuts the withdrawn solidified ingots as they are withdrawn from the secondary crucible.

Abstract: Apparatus (300, 400) for laying an elongate member such as a pipe (306) or a rail (472). Material carried by the apparatus is smelted in a furnace (340) and fed to a casting head (342) by which the elongate member is continuously cast. The so cast elongate member is then laid by the apparatus, as it travels on the ground surface.

Abstract: The present invention provides an electron-beam furnace and a melting method that, in producing an ingot by melting a metal with an electron beam, can suppress the contamination of new impurities in the ingot production, are less likely to again result in inclusion of once evaporated impurities from a molten metal pool within a hearth or a mold, and can be improved in utilization rate. The electron-beam furnace for melting a refractory metal includes a feeder unit for raw materials, a melting unit for raw materials, which is connected to the feeder unit for raw materials and, at the same time, is defined by a furnace wall and a ceiling wall, and includes at least a hearth, a water-cooled mold, and an electron gun, and an evacuation unit for exhaust gas connected to the melting unit for raw materials.

Abstract: A method and apparatus for optimizing melting of titanium for processing into ingots or end products. The apparatus provides a main hearth, a plurality of optional refining hearths, and a plurality of casting molds or direct molds whereby direct arc electrodes melt the titanium in the main hearth while plasma torches melt the titanium in the refining chambers and/or adjacent the molds. Each of the direct arc electrodes and plasma torches is extendable and retractable into the melting environment and moveable in a circular pivoting or side to side linear motion.

Abstract: A method and apparatus for optimizing melting of titanium for processing into ingots or end products. The apparatus provides a main hearth, a plurality of optional refining hearths, and a plurality of casting molds or direct molds whereby direct arc electrodes melt the titanium in the main hearth while plasma torches melt the titanium in the refining chambers and/or adjacent the molds. Each of the direct arc electrodes and plasma torches is extendable and retractable into the melting environment and moveable in a circular pivoting or side to side linear motion.

Abstract: An apparatus (10) and a method for reducing inclusions, shrinkage blowholes, porosity and segregation in metal castings during the casting process, and for improving the grain structure, mechanical properties and yield of ingots and other castings. The apparatus (10) comprises: At least one electrode (14) for forming a moving electric arc (16) over the upper surface (18) of a metallic casting (12) being cast and a stand (20) for suspending the electric arc electrode (14) over the upper surface (18) of the metallic casting (12) during or after pouring and a second electrode (24) attachable to a metallic surface (26) of the mold (28) being used for casting, for completion of an electric circuit (30) including the electric arc (16) and electronic controls (32) connected between the apparatus (10) and a power supply (34).

Abstract: A method and apparatus for optimizing melting of titanium for processing into ingots or end products. The apparatus provides a main hearth, a plurality of optional refining hearths, and a plurality of casting molds or direct molds whereby direct arc electrodes melt the titanium in the main hearth while plasma torches melt the titanium in the refining chambers and/or adjacent the molds. Each of the direct arc electrodes and plasma torches is extendable and retractable into the melting environment and moveable in a circular pivoting or side to side linear motion.

Abstract: A method of making an article includes forming a molten material by melting at least a portion of a mass of a metal and an alloy. The method further includes forming the article by solidifying at least a portion of the molten material within a mold, and contacting the article with plasma during formation of the article. A method for making an article also is disclosed wherein a molten material is formed by melting at least a portion of a mass of one of a metal and an alloy, the molten material is collected within a mold, and at least a portion of the molten material is magnetohydrodynamically stirred within the mold.

Abstract: The present invention relates to a method and apparatus for preparing a metal or metal-alloy product for a casting process—wherein the product is brought into a partly solidified (semi-solidified) state before casting—in which the product contains crystallization nuclei uniformly distributed throughout its volume. The method involves introducing an amount of a chosen alloy (in pulverized form) and an amount of a chosen melt, which is at a temperature above the liquefaction temperature of the alloy, into a crystallization vessel, which is heated to below the liquefaction temperature of the alloy, and mixing the melt and the alloy together in the crystallization vessel by means of electrical and/or magnetic forces to create the desired product.

Abstract: A method for hearthless processing of a solid metallic material consisting essentially of titanium or other metal or alloy thereof which includes providing a solid metal block having a processing surface and a base surface and consisting essentially of titanium or a metal, forming a pool of molten metal on the processing surface of the solid metal block provided in step, adding the metallic material to be processed to the pool of molten metal formed in step, and melting the metallic material to be processed, and removing metallic material melted in step from the pool of molten metal.

Abstract: A maraging steel for use as a mold steel is disclosed. In general, the use of maraging steels in molds is limited by the fact that the martensitic microstructure is not stable at temperatures above 480° C. The precipitate hardening maraging type steel according to the invention contains titanium, molybdenum, cobalt, chromium and nickel and has, in addition to high strength, good ductility, small thermal expansion coefficient and good thermal conductivity, a significantly better thermal stability than other maraging steels, which makes it suitable for use as a mold material particularly in pressure casting.

Abstract: A method for hearthless processing of a solid metallic material consisting essentially of titanium or other metal or alloy thereof which includes providing a solid metal block having a processing surface and a base surface and consisting essentially of titanium or a metal, forming a pool of molten metal on the processing surface of the solid metal block provided in step, adding the metallic material to be processed to the pool of molten metal formed in step, and melting the metallic material to be processed, and removing metallic material melted in step from the pool of molten metal.

Abstract: The present invention concerns a welding mold for butt welding two metal parts by casting a molten filler metal in an imprint defined by a mold. At least one of the components of the mould includes a spacer member shaped and sized so that it can be engaged in a gap between the two parts only if the latter have a mutual separation at least equal to a specific mutual separation, so as to allow the mutual assembly of the components of the mold around the parts to be welded only on this condition. Applications include the welding of railway rails, concrete reinforcing rods and metal bars.

Abstract: A consumable billet for melting and casting a metal matrix composite component is made of a consolidated powder metal matrix composite having a titanium or titanium alloy matrix reinforced with particles. The preferred billet is a blended and sintered powder metal composite billet incorporating titanium carbide or titanium boride into a Ti--6Al--4V alloy.

Abstract: The invention concerns a method for heating a metal melt, in particular molten steel covered with a casting powder, introduced via a submerged outlet into an ingot mould of a continuous casting plant. In order to ensure uniform heat dissipation over the ingot mould and constant frictional forces between the latter and the casting shell, the heat energy is introduced at given points into the surface of the melt bath and the heat energy point on the surface of the melt bath is brought to a predetermined line.

Abstract: Method and apparatus for casting metal strip in which molten metal is introduced between a pair of parallel casting rollers (16) via a tundish (18) and metal delivery nozzle (19b). Casting rollers (16) are cooled so that shells solidify on the moving roller surfaces and are brought together at the nip between them to produce a solidified strip product (20) at the roller outlet. A casting pool is established by pouring a first batch of molten metal at a relatively high temperature above the liquidus temperature of molten metal through the delivery nozzle (19b) and is thereafter maintained by pouring through the delivery nozzle (19b) a second batch of molten metal at a relatively lower temperature. The bottom of the tundish (18) is formed with a well (26) to hold the first batch of molten metal and there is heating means (8) to heat the metal in the well (26).

Abstract: This invention aims at casting a large silicon crystal grain-containing ingot (14) by melting a silicon material (20) by scanning the same with an electron beam, and gradually cooling molten silicon (5) thus obtained. A method of casting a crystalline silicon ingot by electron beam melting, involves of the steps of melting a silicon material (20) by scanning the same with an electron beam, cooling the outer lower surface of molten silicon (5) thus produced while increasing the temperature of the molten silicon (5) suitably so as to generate crystals thereof, and gradually precipitating a crystalline silicon ingot (14) by the weight of itself in accordance with the generation of the crystals.

Abstract: In the disclosed embodiments, vacuum casting of metal ingots is effected by melting metal in a hearth, directing molten metal from the hearth through a hearth outlet to one of a series of mold segments positioned on the periphery of a rotatable drum, and directing an energy beam from an electron gun or plasma gun toward the surface of the molten metal being poured into the mold segment to control solidification of the ingot. After the mold segment has been filled, the drum is indexed to position an adjacent mold segment beneath the hearth outlet. The energy beam is directed toward the surface of the completed ingot in the adjacent segment as well as toward the mold segment being filled to form a smooth surface on the solidified ingot.

Abstract: A method and apparatus for casting a molten metallic material in ingot form are provided wherein the molten metallic material is transported to the ingot mold and an upper surface temperature and temperature distribution of the molten metal pool in the casting mold are measured by an imaging radiometer which is disposed external to a vacuum chamber enclosing the ingot mold, and is disposed to view the ingot pool surface through a sight port. At least one electron beam gun is employed to direct a stream of electrons at the ingot pool surface, the intensity of which is selectively modulated and the impingement of the stream of electrons is simultaneously selectively positioned in order to maintain a desired preselected mold pool surface temperature and temperature distribution thereby yielding a preselected metallurgical structure in the solidified ingot.

Abstract: An apparatus and method for forming round wire from non-round wire has: a heat extracting drum having a semi-circular channel formed in and entirely around its outer circumferential surface; a feed device for directing a precursor wire into the channel; and a heater for melting the precursor wire in the channel. The wire is typically flat and is stood up on edge, perpendicular to the surface of the drum, melted with the heater, solidified and removed. The surface tension and wetting characteristics of the liquid metal cause it to "bead up", forming a near round wire when solidified.

Abstract: There is provided a method of producing a refractory metal or refractory metal-based alloy material by electron beam cold hearth remelting which comprises melting and casting a meltable electrode, characterized in that the electrode used for electron beam cold hearth remelting is made by enveloping a material of refractory metal or refractory metal-based alloy to be melted with an enclosure formed from a metallic material having a higher vapor pressure than said particular refractory metal or from a metallic material which includes component or components having a higher vapor pressure than said particular refractory metal. The evaporation loss of the alloy component or components of the refractory metal-based alloy is compensated for with said metallic material or component(s) of the enclosure or otherwise any metallic material or component(s) of the enclosure provides at least a partial addition of the alloy component or components of the refractory metal-based alloy.

Abstract: In the representative embodiment described in the specification, an electron beam furnace has an evacuation system which maintains the interior of the furnace at a pressure in the range from about 50 microns Hg to 300 microns Hg. The relatively high pressure reduces degassing time from a cold start, suppresses volatilization of constituents of metal being refined, and causes volatilized metal to condense in powder form on a condensing screen. A vibrator assists in removing the powder from the condensing screen. The electron beam gun has a series of compartments which are individually evacuated to maintain the pressure in the compartment containing the cathode at a level less than about 1 micron Hg.

Abstract: The pool to be filamented is liquefied by heating in a crucible. A disk having an edge immersed in the molten pool rotates at high velocity and drives the pool outwards in the form of a ribbon which breaks up into pieces forming the required particles. The portion of the pool in contact with the disk is constantly replenished and, owing to the use of heating means, has sufficient fluidity to satisfy the conditions for extraction, the molten pool being continuously moved horizontally with respect to the disk.

Abstract: A ceramic core molding composition, which includes alumina fibers, zircon, and fumed silica in an amorphous silica base, reduces shrinkage and shrinkage stresses during the core production process. Cores produced utilizing the disclosed composition and method exhibit an improved resistancce to macrocracking over conventionally produced cores.

Abstract: In the embodiments described in the specification, continuous casting of ingots is carried out by transferring molten metal from a hearth to a mold through one or more flow channels which provide flow paths having a shallow angle to the horizontal and which terminates adjacent to the surface of the molten metal in the mold so that the vertical velocity component of the stream of molten metal flowing into the mold is minimal and the horizontal velocity component is low. In one form, the hearth surrounds the mold, providing four shallow-angle flow channels uniformly spaced around the periphery of the mold to avoid unilateral introduction of the molten material into the mold.

Abstract: A method of producing monolithic metal blanks by freezing-on techniques resides in that the surface of a liquid metal melt is heated with the formation of a variable temperature field, defined by the temperature gradient between heating zones and cooling zones. The lines of equal temperatures constitute isotherms. The heating zones are disposed so that the isotherms having a temperature close to the crystallization temperature T.sub.c repeat the shape of the cross-section of the blank to be produced. A dummy bar is immersed equidistantly to the isotherm with the temperature of crystallization T.sub.c. Subsequent drawing out of the dummy bar from the melt with a linear speed defined by the rate of crystallization results in the formation of the blank.

Abstract: The present invention is directed to a method and the associated apparatus for producing rapidly solidified materials by spill chilling. The feed stock can include any of a variety of materials including a high melting point and reactive materials, as well as conventional iron, aluminum, copper and transition base commercially available alloys. A support surface is provided for the solid feed material. Means are provided for both globally and locally heating the feed material. The heating means can include resistant heaters, induction heaters, arcs, electron beam and plasma heaters. A focused energy source such as an electron beam, a laser beam, ion beam or an electric arc can be provided for locally heating the material. The molten feed material is spill chilled onto a moving chill surface. The moving chill surface can be in the form of a continuous belt or the rim of a rotating wheel.

Abstract: In the representative embodiment described in the specification, continuous casting of fine-grain ingots is effected by supplying molten metal to a mold in which the metal is solidified and an ingot is withdrawn downwardly and controlling the temperature in the central region of the molten metal above the ingot at a level at which small crystallites of metal are formed, but large quantities of solid material are not formed. The desired temperature level may be maintained by visual observation of the surface of the metal or pyrometric detection of the temperature of the surface and control of a directional energy input device such as an electron beam gun or a plasma torch to supply sufficient energy to maintain the desired temperature level.

Abstract: The process for producing a metal billet or slab which is substantially homogeneous, fine grained and free of freezing or chemical segregation, which comprises fusing the metal, e.g. titanium or a titanium alloy, by an intense heat source, e.g. a plasma torch, to provide a small molten pool of metal within a charge of the metal, which can be scrap metal such as scrap titanium or a mixture of titanium alloy scrap, master alloy and titanium sponge. The charge of metal, preferably contained in a mold car, is traversed in a substantially horizontal plane with respect to the heat source, thereby causing the small molten pool of metal to also traverse within the metal charge, and continually melting fresh charge metal adjacent to its leading edge and causing rapid freezing of the metal adjacent to the trailing edge of the small molten pool of metal as the melted charge moves away from the heat source.

Abstract: A method of producing a composite nuclear fuel cladding lined with a liner of high purity zirconium characterized in that a raw material of zirconium sponge disposed in a hearth cavity is irradiated with an electron beam while controlling an amount of heat per unit volume (w.sec/mm.sup.3) according to an oxygen removal rate of the raw material determined by oxygen concentration of the raw material and a target oxygen concentration of an ingot for a liner to be refined, and zircaloy cladding is lined with the liner. The hearth cavity has a preferable shape in which the ratio of the cavity surface to the cavity volume is 0.20 mm.sup.-1 or larger.

Abstract: Metal particles are remelted in a fusion zone by electron beam bombardment and formed in a continuous casting mould. Furthermore,(a) the metal particles are evenly distributed over the horizontally positioned floor of a fusion ladle,(b) the metal particles are joined together into a plate-shaped structure by means of the electron beam, whereafter(c) the floor of the fusion ladle is moved into a position inclined in relation to the horizontal,(d) the electron beam is guided upwards over the sloping, plate-shaped particle structure so that this is firstly preheated and fused directly thereafter, while(e) the molten metal running over the lower part of the floor is simultaneously kept liquid by electron beam bombardment, whereafter(f) the electron beam is guided back downwards over the sloping floor of the fusion ladle, and(g) the floor of the fusion ladle is returned to the horizontal starting position and is once again charged with metal particles according to feature (a).

Abstract: Tantalum or niobium in the form of powder or pieces containing volatile impurities, e.g. sodiothermic tantalum powder, is first converted into crude cast metal by plasma melting and then the crude cast metal is refined by electron beam melting.

Abstract: A method is described for continuously casting an ingot of a metal alloy of the type having a substantial liquidus-solidus temperature range so that the ingot will have a "smooth" surface free of hot-tears. A succession of substantially equal volume quantities of the molten alloy is poured into a continuous casting mold at a pressure of less than about 10.sup.-3 Torr. The quantity of each pour is sufficient to cover the entire cross section of the mold by flow under the influence of gravity and each quantity is allowed to substantially solidify between pours to form successive axial increments which make up the ingot. Each increment is allowed to cool for at least about 30 seconds between pours to form a sufficiently solid side-wall to prevent hot-tears.

Abstract: A high-purity metal member is produced by charging raw material such as sponge zirconium into a cavity of a mold such as a hearth under a vacuum atmosphere; irradiating the material with electron beams to melt it at a limited area of the cavity while forming a molten metal pool and irradiating the pool with the electron beam thereby elevate the molten metal pool to evaporate away impurities therein; and shifting the mold relative to the electron beams to provide a high-purity metal member. The metal pool is limited in its size and irradiated high energy density electron beams so that the temperature is raised whereby the impurities are easily evaporated away. The mold may have an annular cavity. In case of high-purity sleeve formation, the electron beams are irradiated onto the raw material while rotating the mold so that melting and solidification appear in a circumferential direction to be repeated. The impurities are repeatedly exposed to the electron beams.

Abstract: The raw material in a raw material feeding apparatus of a melting cast installation is supplied, through a guide cylinder vertically mounted inside a furnace wall, towards a melting pot of a casting apparatus. A plurality of plasma arc torches, for heating the raw material, are positioned on the upper rotatable half of said furnace wall and are radially arranged around the axis of said guide cylinder with front ends thereof directed individually towards said melting pot. The raw material feeding apparatus may consist of a rotatable cylindrical drum laid substantially horizontally and a helical compartment wall to define a raw material path inside said cylindrical drum. A cylindrical limiter may be vertically mounted, inside said guide cylinder, for vertical movement so as to form an adjustable annular path for raw material between said limiter and the internal surface of said guide cylinder.