Abstract: A method for casting dental metals with a casting apparatus including a hermetically sealed casting chamber in which an arc electrode is located above, a crucible made of an electrically conductive material is positioned below the arc electrode, and a mold provided with a closed vent is disposed below the crucible, the method including by positioning a dental metal ingot on the crucible, evacuating the casting chamber to vacuum, feeding a small amount of an inert gas at such a pressure as to induce arc discharge all over the upper surface of the ingot, thereby melting the ingot placed on the crucible by arc discharge from the arc electrode, pouring the thus obtained molten metal into a mold through its inlet, and immediately feeding an additional amount of the inert gas into the casting chamber to increase its internal pressure to a level suitable for casting. Also the additional amount of the inert gas is rapidly fed into the casting chamber through a gas tank in the vicinity of the casting chamber.

Abstract: A method for casting dental metals with a casting apparatus including a melting chamber in which there are located an arc electrode above and a crucible formed of an electrically conductive material positioned below the arc electrode, and a mold chamber divided from the melting chamber by a partition wall having a through-hole at a position below the crucible and housing a mold box receiving a mold provided with an extending open vent positioned below the through-hole, the melting chamber communicating hermetically with the mold chamber through the mold, which is characterized by positioning a dental metal ingot on the crucible, vacuumizing the melting and mold chambers, feeding a small amount of an inert gas into the melting chamber at such a pressure as to induce arc discharge all over the upper surface of the ingot, thereby melting the ingot placed on the crucible by arc discharge from the arc electrode, pouring the thus obtained molten metal into the mold through its inlet, and immediately feeding an addi

Abstract: Zirconium or hafnium tubeshells, billets and channel sheets are produced by plasma arc melting the metal to form a liquid metal pool. The pool is poured into a mold to form a near net shape. The near net shape is reduced to final size while maintaining the metal temperature below the alpha-beta transition temperature throughout the size reducing step.

Abstract: A method and electrode assembly for use in consumable electrode arc melting of metals and alloys, particularly titanium and titanium-base alloys. The method includes forming an assembly including an electrode of the metal or alloy to be melted. An elongated ring, which is of metal or alloy construction, has one end connected to one end surface of the electrode and another end connected to an electrode holder, which is connected to a source of electrical potential. The ring has an outside diameter less than the outside diameter of the electrode to form an annular marginal area on the end surface of the electrode. This annular marginal area is defined by the ring and the periphery of the end surface of the electrode. This assembly is positioned within a cooled mold of conductive material, which mold is also connected to a source of electrical potential.

Abstract: A process for bonding a mixture of substances together. The process includes the steps of forming a mixture of substances; heating the mixture of substances until the mixture is molten; pouring the molten mixture of substances into a mold; and forming a magnetic field around the mold.

Abstract: A method of improving an arc spray process for making metal matrix composite monotapes by providing an AC power supply and individually controlled wire feeds to promote even melting of the wires particularly wires formed of metals and alloys having high temperature melting points.

Abstract: An apparatus for preparing metallic radioactive waste material for storage is disclosed. The radioactive waste material is placed in a radiation shielded enclosure. The waste material is then melted with a plasma torch and cast into a plurality of successive horizontal layers in a mold to form a radioactive ingot in the shape of a spent nuclear fuel rod storage canister. The apparatus comprises a radiation shielded enclosure having an opening adapted for receiving a conventional transfer cask within which radioactive waste material is transferred to the apparatus. A plasma torch is mounted within the enclosure. A mold is also received within the enclosure for receiving the melted waste material and cooling it to form an ingot. The enclosure is preferably constructed in at least two parts to enable easy transport of the apparatus from one nuclear site to another.

Abstract: The bottom of a solid metal charge melts to fill a form below the charge. During melting, usually, the metal that enters the form remains continuous with an unused solid part of the charge. After cooling, the formed metal is removed together with the unused part of the charge--and usually with the form too. They are separated later or in a different operation, and another charge is positioned immediately for melting into another form, so the useful duty cycle is very high. A preferred form of the invention uses an upper melting chamber and a lower forming chamber, separated by a horizontal wall but communicating by an aperture through the wall. The charge and form are placed against the wall from below to block the aperture. The charge preferably extends up through the aperture into or toward the melting chamber, where an arc electrode or other heater melts the top of the charge, particularly near its center.

Abstract: The method consists in that a flat work in an initial position is oriented horizontally between cooled mold beams. Plasma torches are arranged in line across the parallel side edges so that the anode spots of the extreme torches are confined by said edges of the work. By supplying a plasma forming gas and electric current to the plasma torches the work is heated with the formation of a metal pool which extends across the work from edge to edge. By relatively moving the work and the plasma torches in a horizontal plane and along the edges of the work movement of the metal pool over the surface thereof is effected and thereby a remelted layer as thick as the pool is deep, is obtained. The apparatus for carrying out the method comprises a sealed chamber containing a mold having two beams arranged in a horizontal plane and being parallel to one another.

Abstract: A paint or coating composition which contains only pure Ziroconium containing compounds, and a small amount of NH.sub.4 (OH).sub.2 and acid is applied to the vertical walls of a vacuum arc furnace Copper crucible to form a stable, substantially uniform, coating thereon. The Zirconium coating composition of the present invention is free of Aluminum and Aluminum compounds and consists essentially of Zirconium Oxide suspended in a water-based Zirconyl Nitrate gel, to which small amounts of base and acid have been sequentially added. This coating eliminates the introduction of spurious impurities into the surface of the zirconium ingot formed during vacuum are melting of a zirconium compact.

Abstract: A process for the introduction of metal elements in a plasma-state into metal melts where the additive element is brought to the plasma state and, by means of an inert carrying gas, is caused to spread in the fluid mass of the metal melt. The additive element is brought to the plasma state by using an electric arc.

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: Metal material is melted by moving the magnetic flux of electromagnets virtually perpendicular to an arc column to apply Lorentz force to the arc column and the metal material so that the arc column can move over the metal material surface. The movement direction and speed of the arc column are determined by detecting the arc voltage of the arc column. Feed back control is performed by comparing the obtained detection data with preset data so that optimum control is performed, and the molten metal is poured into a casting mold.

Abstract: An apparatus and method is disclosed which is adapted to consolidate and melt reactive metallic materials, and to produce a "first ingot" which is suitable for subsequent evaluation and qualification under existing specifications for such materials in the aerospace industry. The apparatus comprises an enclosed heating chamber adapted to be substantially evacuated of air, and a hearth is positioned within the chamber for supporting the metallic material to be melted. Also, a plasma arc torch is mounted to the heating chamber, which is operable in the transfer arc mode wherein an arc extends from the rear electrode of the torch to the hearth. The rear electrode of the torch is of elongate tubular configuration, which permits a major portion of the length of the arc to be located within the torch itself, which permits the torch to deliver a high level of power in the vacuum environment within the heating chamber.

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.

Abstract: A method of producing sound metal castings, particularly of reactive metals, by striking an electrical arc in a gap defined by adjacent end faces of opposed elongate electrodes, wherein the electrodes are mounted for rotation about longitudinal axes that are parallel and offset with respect to each other, realizing substantially complete overlapping of the adjacent end faces during rotation of the electrodes to cause uniform depletion of same, and wherein the metal droplets derived at the gap are maintained in a fully molten condition until they have been cast into an adjacent mold.

Abstract: An arc furnace and investment casting apparatus includes a copper base with an integrally formed crucible having a passage therethrough. A vacuum chamber is positioned on the top of the copper crucible with a non-consumable cathode projecting into the chamber to effect melting of metal placed in the crucible. A vacuum chamber is also suspended beneath the crucible for support of a mold to receive molten metal flowing through the passage.

Abstract: A method for casting material melted by arc discharge and an arc melting apparatus useful with a precision casting machine, the invention is practiced by initiation of an arc discharge at an arc current lower than the steady state current normally used for arc melting, thereby to prevent starting shock. Current level is subsequently increased in a rapid and regular manner to a steady state current for melting in a stable manner the material which is to be cast. The apparatus of the invention includes a small and compact arc power source provided with apparatus for controlling the arc current which is applied to the material to be melted. When utilized with a precision casting apparatus, the invention improves the manufacture of artificial teeth, accessories, industrial mechanical parts and the like.

Abstract: A method for rotary refining and casting comprising the remelting of an alloy electrode suspended within an essentially cylindrical mold wherein said electrode and said mold are both rotated about their coincident axes of symmetry; heating the tip of said electrode to a sufficiently high temperature to cause melting, with the metal droplets formed at said tip of said electrode descending into said mold under the combined effect of gravitational and centrifugal forces, wherein said droplets form a liquid pool, the free surface of said pool assuming the configuration of a paraboloid of revolution about said axis of rotation, resulting in a shallow pool with high surface area; said pool progressively solidifying into a fine-grain ingot exhibiting high homogeneity and cleanliness; the energy for melting said tip of said electrode and for maintaining said pool molten provided by converting electrical energy to thermal energy at a gap maintained between said electrode and said molten pool.

Abstract: A method of controlling relative movement between an ingot and a mold consists of monitoring the level of the metal pool in the mold by measuring the voltage between the ingot and a mold section disposed above the metal pool, in contact with the bath of molten slag and insulated electrically from the ingot and from the ingot-forming mold section; comparing an instantaneous value of said voltage with a predetermined value and varying the relative speed of the ingot and the mold depending on a signal proportional to the difference between the instantaneous and the predetermined values of said voltage so that the predetermined level of the metal pool is restored.

Abstract: A method of casting high melting point metal such as refractory metals into ngots to provide substantially improved strength and density. A quantity of high melting point metal is placed in an arc area of a furnace having a "T" shaped vacuum chamber with a pair of opposing electrodes which generate an arc to cause droplets of the metal to melt from the heat thereby generated. The droplets fall into a mold positioned to receive the droplets and shaped to form the desired ingot. The method includes an additional step of further heating the droplets as they fall into the mold with a plasma arc gun mounted inside the furnace. The gun is directed to impinge its heat torch to control the rate of solidification such that a small pool of the liquid phase is maintained on the ingot. The last step comprises solidifying the molten metal in the ingot by controlling the plasma arc gun and the heat generated from it.