A method for producing a metal ingot by using an electron-beam melting furnace including an electron gun capable of controlling a radiation position of an electron beam, and a hearth that accumulates a molten metal of a metal raw material, in which, in a downstream region between an upstream region in which the metal raw material is supplied onto the surface of the molten metal and a first side wall, an irradiation line is disposed so as to block a lip portion and so that two end portions are positioned in the vicinity of the side wall of the hearth. A first electron beam is radiated onto the surface of the molten metal along the irradiation line, and the first electron beam is radiated along the irradiation line. By this means, the surface temperature (T2) of the molten metal along the irradiation line is made higher than the average surface temperature (T0) of the entire surface of the molten metal in the hearth, and a molten metal flow from the irradiation line toward upstream that is a direction toward the opposite side to the first side wall is formed in an outer layer of the molten metal.

A metallurgical system for producing metals and metal alloys includes a fluid cooled mixing cold hearth having a melting cavity configured to hold a raw material for melting into a molten metal, and a mechanical drive configured to mount and move the mixing cold hearth for mixing the raw material. The system also includes a heat source configured to heat the raw material in the melting cavity, and a heat removal system configured to provide adjustable insulation for the molten metal. The mixing cold hearth can be configured as a removal element of an assembly of interchangeable mixing cold hearths, with each mixing cold hearth of the assembly configured for melting a specific category of raw materials. A process includes the steps of providing the mixing cold hearth, feeding the raw material into the melting cavity, heating the raw material, and moving the mixing cold hearth during the heating step.

[Problem]

To provide a method for producing a metal ingot, which makes it possible to inhibit impurities contained in molten metal in a hearth from being mixed into the ingot.

[Solution]

A method for producing a metal ingot by using an electron-beam melting furnace having an electron gun and a hearth that accumulates a molten metal of a metal raw material, wherein the metal raw material is supplied to the position on a supply line disposed along a second side wall of the hearth that accumulates the molten metal of the metal raw material. A first electron beam is radiated along a first irradiation line that is disposed along the supply line and is closer to a central part of the hearth relative to the supply line on the surface of the molten metal. By this means, a surface temperature (T2) of the molten metal at the first irradiation line is made higher than an average surface temperature (T0) of the entire surface of the molten metal in the hearth, and in an outer layer of the molten metal, a first molten metal flow is formed from the first irradiation line toward the supply line.

[Problem]

To provide a method for producing a metal ingot, which makes it possible to inhibit impurities contained in molten metal in a hearth from being mixed into the ingot.

[Solution]

A method for producing a metal ingot by using an electron-beam melting furnace having an electron gun and a hearth that accumulates a molten metal of a metal raw material, wherein the metal raw material is supplied to the position on a supply line disposed along a second side wall of the hearth that accumulates the molten metal of the metal raw material. A first electron beam is radiated along a first irradiation line that is disposed along the supply line and is closer to a central part of the hearth relative to the supply line on the surface of the molten metal. By this means, a surface temperature (T2) of the molten metal at the first irradiation line is made higher than an average surface temperature (T0) of the entire surface of the molten metal in the hearth, and in an outer layer of the molten metal, a first molten metal flow is formed from the first irradiation line toward the supply line.

A tantalum or tantalum alloy which contains pure or substantially pure tantalum and at least one metal element selected from the group consisting of Ru, Rh, Pd, Os, Ir, Pt, Mo, W and Re to form a tantalum alloy that is resistant to aqueous corrosion. The invention also relates to the process of preparing the tantalum alloy.

A tantalum or tantalum alloy which contains pure or substantially pure tantalum and at least one metal element selected from the group consisting of Ru, Rh, Pd, Os, Ir, Pt, Mo, W and Re to form a tantalum alloy that is resistant to aqueous corrosion. The invention also relates to the process of preparing the tantalum alloy.

Disclosed is an AMS process using a water-leachable alloy that reacts with water and dissolves, and a porous metal manufactured using the same. An AMS precursor including element groups that are selected in consideration of the relationship of heat of mixing with the water-leachable alloy composition to be subjected to the AMS process is immersed in the alloy melt, thus manufacturing a bi-continuous structure alloy. The bi-continuous structure alloy is subjected to dealloying using water, thus manufacturing the porous metal. The water-leachable alloy is a Ca-based alloy having high reactivity to water and high oxidation resistance at high temperatures, and a dealloying process thereof is performed using only pure water, unlike a conventional dealloying process performed using a toxic etching solution of a strong acid/strong base. The metal porous body has high elongation, a large surface area, and low thermal conductivity.

Disclosed is an AMS process using a water-leachable alloy that reacts with water and dissolves, and a porous metal manufactured using the same. An AMS precursor including element groups that are selected in consideration of the relationship of heat of mixing with the water-leachable alloy composition to be subjected to the AMS process is immersed in the alloy melt, thus manufacturing a bi-continuous structure alloy. The bi-continuous structure alloy is subjected to dealloying using water, thus manufacturing the porous metal. The water-leachable alloy is a Ca-based alloy having high reactivity to water and high oxidation resistance at high temperatures, and a dealloying process thereof is performed using only pure water, unlike a conventional dealloying process performed using a toxic etching solution of a strong acid/strong base. The metal porous body has high elongation, a large surface area, and low thermal conductivity.

In various embodiments, a metal alloy resistant to aqueous corrosion consists essentially of or consists of niobium with additions of tungsten, molybdenum, and one or both of ruthenium and palladium.

A method of vacuum arc remelting an ingot provided in a crucible assembly having an electrode includes generating a rotating magnetic field normal to a longitudinal axis of the ingot and localized to an arc region during remelting. The rotating magnetic field interacts with a melting current to produce a rotating arc directed radially outward.