A method of fabricating a low alloy steel ingot, the method including a) melting all or part of an electrode by a vacuum arc remelting method, the electrode, before melting, including iron and carbon, the melted portion of the electrode being collected in a crucible, thus forming a melt pool within the crucible; and b) solidifying the melt pool by heat exchange between the melt pool and a cooling fluid, the heat exchange applied serving to impose a mean solidification speed during step b) that is less than or equal to 45 μm/s and to obtain an ingot of low alloy steel.

A method of fabricating a low alloy steel ingot, the method including a) melting all or part of an electrode by a vacuum arc remelting method, the electrode, before melting, including iron and carbon, the melted portion of the electrode being collected in a crucible, thus forming a melt pool within the crucible; and b) solidifying the melt pool by heat exchange between the melt pool and a cooling fluid, the heat exchange applied serving to impose a mean solidification speed during step b) that is less than or equal to 45 μm/s and to obtain an ingot of low alloy steel.

The invention relates to a method for extracting metal from metal-containing raw material in a batch process by using a direct current electric arc furnace (100) having one or more than one top electrode (125) and at least one bottom electrode (115), wherein the method comprises the following steps: adding the metal-containing raw material to the furnace (100), thereby obtaining a loaded bath, moving the top electrode(s) (125) onto the raw material, heating the loaded bath in a heating step by applying direct current through the top electrode(s) to provide an arc to melt the raw material, thereby obtaining molten metal (202), wherein an average voltage during the heating step is from 20 V to 110 V, and forming solid metal from the molten metal (202). The invention further relates to a direct current electric arc furnace, a system comprising a direct current electric arc furnace, and a solid metal obtainable by the method.

A vacuum arc remelt apparatus comprising a crucible having a wall, said wall having an interior and an exterior opposite said interior; an electrode within the crucible proximate the interior; an ingot within the crucible and below the electrode, wherein said ingot includes a crown and shelf; and a vibration source at the exterior of the crucible proximate the crown and shelf.

A vacuum arc remelt apparatus comprising a crucible having a wall, said wall having an interior and an exterior opposite said interior; an electrode within the crucible proximate the interior; an ingot within the crucible and below the electrode, wherein said ingot includes a crown and shelf; and a vibration source at the exterior of the crucible proximate the crown and shelf.

A metal purifying method having: a local heating step of heating an aluminum-based molten metal in a first region on a molten metal surface of the aluminum-based molten metal; and a local low pressure step of lowering the pressure in a second region on the molten metal surface to a pressure lower than the pressure in the first region. The second region is different from the first region. This allows a specific element to be vaporized from the second region to purify the aluminum-based molten metal. The specific element is one or more of Zn, Mg, or Pb having a saturated vapor pressure higher than that of Al. This is effective not only in a purifying method for removing a specific element from an aluminum-based molten metal but also in a method of recovering a specific element, which can be a resource, from an aluminum-based molten metal.

A control system includes a vision system including an imaging device and a VAR monitoring system configured to determine a power adjustment phase of the VAR process based on the images from the vision system and a process parameter. The VAR monitoring system includes a vision analysis module configured to analyze the images from the vision system to detect a melt marker based on a remelt image process model, and a prediction module configured to predict an operational characteristic of the VAR process that is associated with the power adjustment relative to a melt marker location and a remelt prediction model. The VAR monitoring system is configured to initiate the power adjustment phase in response to the melt marker satisfying a predetermined melt marker condition, the operational characteristic of the VAR process satisfying a predetermined operational condition, or a combination thereof.

A control system includes a vision system including an imaging device and a VAR monitoring system configured to determine a power adjustment phase of the VAR process based on the images from the vision system and a process parameter. The VAR monitoring system includes a vision analysis module configured to analyze the images from the vision system to detect a melt marker based on a remelt image process model, and a prediction module configured to predict an operational characteristic of the VAR process that is associated with the power adjustment relative to a melt marker location and a remelt prediction model. The VAR monitoring system is configured to initiate the power adjustment phase in response to the melt marker satisfying a predetermined melt marker condition, the operational characteristic of the VAR process satisfying a predetermined operational condition, or a combination thereof.

An object of the present invention is to provide a Zr—Nb-based alloy material as a low-magnetic susceptibility alloy having a high corrosion resistance while maintaining a magnetic susceptibility equivalent to or less than the magnetic susceptibility of the biological alloy of the related art, a method for manufacturing the alloy material, and a Zr—Nb-based alloy product. The Zr—Nb-based alloy material according to the present invention includes, as a chemical composition, 3% by mass or more and 18% by mass or less of Nb, 12% by mass or less of Ti, 6% by mass or less of Cr, 6% by mass or less of Cu, 5% by mass or less of Bi, and a remainder consisting of Zr and unavoidable impurities, in which isothermal ω phase particles are dispersed and precipitated in β phase crystal grains of a parent phase.

The invention discloses a method about the integration of the metallurgical purification of metallic gadolinium and the preparation of gadolinium oxide nanoparticles (GONPs) by arc plasma. The method includes the metallurgical purification and the nanoparticle preparation. Firstly, the gadolinium ingot and a tungsten rod respectively act as an anode and a cathode. After the arc furnace is evacuated and then is filled with a working atmosphere, impurities in the gadolinium ingot are removed in the form of volatilization to obtain purified gadolinium by the first arc discharge. Whereafter, the purified gadolinium and the tungsten rod are used as the anode and cathode. After the arc furnace also is evacuated and then also is filled with a working atmosphere, GONPs are obtained from the inner wall of the arc furnace though the second arc discharge. The metallurgical purification of metallic gadolinium and the preparation of GONPs were integrated by arc plasma.