A control system for a vacuum arc remelting (VAR) process for a metal includes a direct current (DC) power source, a ram drive, voltage drip short sensor, and a controller, which includes a processor. The drip short sensor may be configured to measure a drip short frequency of the electric arc over a period of time. The controller is configured to determine a real time arc gap length between the electrode tip and the melt pool based on a correlation between the drip short frequency and arc gap length. The controller is further configured to control power input to the electrode by the DC power supply by determining an input power level to input to the electrode based on the real time arc gap length, the input power level configured to generate a desired arc gap length, by the DC power supply, at the input power level.

The invention provides a calculation method for operating resistance in a dual-electrode DC electric-smelting furnace for magnesium, including the following steps of: calculating a raw material resistance: simplifying a raw material model as an electrode-centered cylindrical model, determining an electric-field strength of each point in an electric field generated by a raw material layer around an electrode in the cylindrical model, calculating a raw material voltage between two electrodes according to the electric-field strength of each point in the electric field, and further obtaining the raw material resistance between the two electrodes; calculating an electric arc-resistance relation model: determining a relation between an actual electric arc length and a distance from the electrode to a surface of a smelting pool, and calculating a relation between an electric arc voltage and the actual electric arc length, namely the electric arc-resistance relation model; and calculating a smelting pool resistance, namely the sum in series of the smelting pool resistance of the two electrodes.

The invention provides a calculation method for operating resistance in a dual-electrode DC electric-smelting furnace for magnesium, including the following steps of: calculating a raw material resistance: simplifying a raw material model as an electrode-centered cylindrical model, determining an electric-field strength of each point in an electric field generated by a raw material layer around an electrode in the cylindrical model, calculating a raw material voltage between two electrodes according to the electric-field strength of each point in the electric field, and further obtaining the raw material resistance between the two electrodes; calculating an electric arc-resistance relation model: determining a relation between an actual electric arc length and a distance from the electrode to a surface of a smelting pool, and calculating a relation between an electric arc voltage and the actual electric arc length, namely the electric arc-resistance relation model; and calculating a smelting pool resistance, namely the sum in series of the smelting pool resistance of the two electrodes.

An inline thermal treatment system for thermally treating a continuous product includes a gas supply system configured to supply a first gas flow and a power source configured to supply power. The system includes a plasma torch configured to receive the first gas flow from the gas supply system and power from the power source to form a plasma arc, wherein the plasma arc heats a portion of the continuous product disposed near the plasma arc.

An inline thermal treatment system for thermally treating a continuous product includes a gas supply system configured to supply a first gas flow and a power source configured to supply power. The system includes a plasma torch configured to receive the first gas flow from the gas supply system and power from the power source to form a plasma arc, wherein the plasma arc heats a portion of the continuous product disposed near the plasma arc.

The present invention provides an electric furnace including: a cylindrical furnace wall; a furnace cover that is provided at an upper end of the furnace wall; and a furnace bottom that is provided at a lower end of the furnace wall and includes a deep bottom portion and a shallow bottom portion as a region having a height of 150 mm to 500 mm from a deepest point of the deep bottom portion, in which a slag pouring port into which molten slag or a solidified slag lump is capable of being poured from a slag transport container directly or through a tilting trough is provided, the slag pouring port overlaps the shallow bottom portion in a plan view, and the area ratio of the shallow bottom portion to the furnace bottom in a plan view is 5% to 40%.

The present invention provides an electric furnace including: a cylindrical furnace wall; a furnace cover that is provided at an upper end of the furnace wall; and a furnace bottom that is provided at a lower end of the furnace wall and includes a deep bottom portion and a shallow bottom portion as a region having a height of 150 mm to 500 mm from a deepest point of the deep bottom portion, in which a slag pouring port into which molten slag or a solidified slag lump is capable of being poured from a slag transport container directly or through a tilting trough is provided, the slag pouring port overlaps the shallow bottom portion in a plan view, and the area ratio of the shallow bottom portion to the furnace bottom in a plan view is 5% to 40%.

A metallurgical furnace including a vessel, in turn having a lower shell for containing the metal bath, the metal bath being composed of molten metal and an overlying layer of slag, wherein the lower shell is tiltingly supported and is provided with a deslagging opening for evacuating the slag and with a tapping opening for tapping the molten metal, and an upper shell removably positioned on the lower shell and provided with at least one inlet opening for feeding, through the same, charge material in the solid state or in the molten state, a closing roof for the upper closing of the vessel, wherein the closing roof is removably positioned on the upper shell and is provided with a passage opening for the passage, through the same, of at least one electrode and at least one charge opening for feeding, through the same, charge material in the solid state, wherein at least one of the inlet openings, the passage opening, the charge opening is closed or can be associated with a closing element of the removable type, and wherein the lower shell has a diameter D and the vessel has an overall height H ranging from 0.70 D to 1.25 D, preferably ranging from 0.70 D to 0.80 D if the furnace is used as an electric arc furnace and from 0.80 D to 1.25 D if the furnace is used as a converter.

A metallurgical furnace including a vessel, in turn having a lower shell for containing the metal bath, the metal bath being composed of molten metal and an overlying layer of slag, wherein the lower shell is tiltingly supported and is provided with a deslagging opening for evacuating the slag and with a tapping opening for tapping the molten metal, and an upper shell removably positioned on the lower shell and provided with at least one inlet opening for feeding, through the same, charge material in the solid state or in the molten state, a closing roof for the upper closing of the vessel, wherein the closing roof is removably positioned on the upper shell and is provided with a passage opening for the passage, through the same, of at least one electrode and at least one charge opening for feeding, through the same, charge material in the solid state, wherein at least one of the inlet openings, the passage opening, the charge opening is closed or can be associated with a closing element of the removable type, and wherein the lower shell has a diameter D and the vessel has an overall height H ranging from 0.70 D to 1.25 D, preferably ranging from 0.70 D to 0.80 D if the furnace is used as an electric arc furnace and from 0.80 D to 1.25 D if the furnace is used as a converter.

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.