Disclosed in this application are a large-sized high-Nb superalloy ingot and a smelting process thereof. The smelting process includes: vacuum induction melting to prepare a plurality of vacuum induction melting ingots with the same composition which are used for preparing electroslag electrodes with the same number as the vacuum induction melting ingots for use in electroslag remelting, preparing a consumable electrode from the prepared consumable electroslag electrodes, and performing vacuum consumable arc remelting for a plurality of times by using the consumable electroslag electrodes as raw material. A large-sized high-Nb superalloy ingot having a weight of 15 tons or above and a diameter of 800 mm or above can be prepared from such process.

Disclosed in this application are a large-sized high-Nb superalloy ingot and a smelting process thereof. The smelting process includes: vacuum induction melting to prepare a plurality of vacuum induction melting ingots with the same composition which are used for preparing electroslag electrodes with the same number as the vacuum induction melting ingots for use in electroslag remelting, preparing a consumable electrode from the prepared consumable electroslag electrodes, and performing vacuum consumable arc remelting for a plurality of times by using the consumable electroslag electrodes as raw material. A large-sized high-Nb superalloy ingot having a weight of 15 tons or above and a diameter of 800 mm or above can be prepared from such process.

Disclosed in this application are a large-sized high-Nb superalloy ingot and a smelting process thereof. The smelting process includes: vacuum induction melting to prepare a plurality of vacuum induction melting ingots with the same composition which are used for preparing electroslag electrodes with the same number as the vacuum induction melting ingots for use in electroslag remelting, preparing a consumable electrode from the prepared consumable electroslag electrodes, and performing vacuum consumable arc remelting for a plurality of times by using the consumable electroslag electrodes as raw material. A large-sized high-Nb superalloy ingot having a weight of 15 tons or above and a diameter of 800 mm or above can be prepared from such process.

Disclosed in this application are a large-sized high-Nb superalloy ingot and a smelting process thereof. The smelting process includes: vacuum induction melting to prepare a plurality of vacuum induction melting ingots with the same composition which are used for preparing electroslag electrodes with the same number as the vacuum induction melting ingots for use in electroslag remelting, preparing a consumable electrode from the prepared consumable electroslag electrodes, and performing vacuum consumable arc remelting for a plurality of times by using the consumable electroslag electrodes as raw material. A large-sized high-Nb superalloy ingot having a weight of 15 tons or above and a diameter of 800 mm or above can be prepared from such process.

Method and means for suppressing discoloration during thermal treatment of a product of a magnesium containing aluminium alloy, the alloy contains in wt. % Mg: 0.45-12.0, with a preferred range of 0.45-6.0 wt %. The product, being either an extrusion billet, a sheet ingot, a cast product, or a forged product is heated to a temperature T where it is prone to surface discoloration and oxidation, wherein during the thermal treatment it is exposed to a suppressing atmosphere comprising 0.5-5.0% CO.sub.2 gas with a preference for 0.5-1.5% CO.sub.2 gas.

FIG. 3 to be published with the abstract

The present invention relates to a method (1) of producing a metal superalloy (10) comprising the steps of providing a charge of metal materials (2); melting said charge of metal materials (2) in an electric-arc furnace (3) to obtain a first melt (3A) of said charge of metal materials (2); solidifying (5) said first melt (3A) to obtain first ingots (5A); melting said first ingots (5A) in a V.I.D.P. furnace (6) to obtain a second melt (6A); solidifying (7) said second melt (6A) to obtain second ingots (7A); melting said second ingots (7A) in a V.A.R. furnace (8) to obtain a third melt (8A); solidifying (9) said third melt (8A) to obtain a metal superalloy (10). The method (1) is characterized in that the charge of metal materials (2) has a weight amount ranging from forty to sixty tons, and it includes a step of carrying out an A.O.D. treatment (4) on said first melt (3A) to obtain a decarburized and refined first melt (4A); said melting in the V.I.D.P. furnace (6) and said melting in the V.A.R. furnace (8) are carried out sequentially on said first melt (4A) resulting from said A.O.D. treatment (4).

The present invention relates to a method (1) of producing a metal superalloy (10) comprising the steps of providing a charge of metal materials (2); melting said charge of metal materials (2) in an electric-arc furnace (3) to obtain a first melt (3A) of said charge of metal materials (2); solidifying (5) said first melt (3A) to obtain first ingots (5A); melting said first ingots (5A) in a V.I.D.P. furnace (6) to obtain a second melt (6A); solidifying (7) said second melt (6A) to obtain second ingots (7A); melting said second ingots (7A) in a V.A.R. furnace (8) to obtain a third melt (8A); solidifying (9) said third melt (8A) to obtain a metal superalloy (10). The method (1) is characterized in that the charge of metal materials (2) has a weight amount ranging from forty to sixty tons, and it includes a step of carrying out an A.O.D. treatment (4) on said first melt (3A) to obtain a decarburized and refined first melt (4A); said melting in the V.I.D.P. furnace (6) and said melting in the V.A.R. furnace (8) are carried out sequentially on said first melt (4A) resulting from said A.O.D. treatment (4).

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 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.

[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.