A method is disclosed for smelting low nitrogen steel using a dual-shell electric furnace having two furnace shells and an arc power system for alternatively electrically heating the furnace shells in which one of the two furnace shells is respectively sequentially subjected to electric heating, feeding, sealing of a molten pool and blowing of a combustion medium and oxygen to initiate smelting; when the temperature of molten steel in the furnace shell subjected to electric heating reaches a target temperature, initiating electric heating of the other furnace shell. The method can shorten the smelting period and improve the throughput of a production line of an electric furnace to efficiently meet the market requirements for low nitrogen steel while reducing the emission of environmental pollutants associated with known processes.

A treatment method of molten steel capable of preventing metal components in molten steel from being reoxidized by reacting with oxides in molten slag, inhibiting occurrence of inclusions, and reducing nitrogen in the molten steel. The treatment method of molten steel in which a potential difference is applied between the molten steel and the molten slag by using a direct-current power supply and through two electrodes which are a negative electrode being an electrode in contact with the molten steel and a positive electrode being another electrode in contact with only the molten slag is characterized by including: a deoxidation step of deoxidizing the molten steel by adding a deoxidizing agent to the molten steel; and a step of applying the potential difference after the deoxidation step. Also, a steel production method by which the obtained molten steel is cast after components thereof are adjusted.

To produce manganese containing ferroalloy for steel production, an agglomeration mixture is produced which comprises chromite ore concentrate and manganese ore fines with a grain size smaller than 6-9 mm. The mixture is agglomerated to produce green agglomeration products, such as pellets or other types of agglomerates. The green agglomeration products are sintered in a steel belt sintering furnace to produce either sinter or sintered pellets. The sinter or sintered pellets are smelted in a submerged arc furnace to produce manganese and chromium containing ferroalloy. The ferroalloy produced by the method comprises 6.0-35 w-% manganese and 31-54 w-% chromium.

An electrode includes a network of compressed interconnected nanostructured carbon particles such as carbon nanotubes. Some nanostructured carbon particles of the network are in electrical contact with adjacent nanostructured carbon particles. Electrodes may be used in various devices, such as capacitors, electric arc furnaces, batteries, etc. A method of producing an electrode includes confining a mass of nanostructured carbon particles and densifying the confined mass of nanostructured carbon particles to form a cohesive body with sufficient contacts between adjacent nanostructured carbon particles to provide an electrical path between at least two remote points of the cohesive body. The electrodes may be sintered to induce covalent bonding between the nanostructured carbon particles at contact points to further enhance the mechanical and electrical properties of the electrodes.

At least one measurement value of a measurement variable characterizing the operating state of each of a plurality of system components that influence the operating conditions of an arc furnace is detected and compared to a respective currently permissible threshold value for the measurement variable. A maximum power that can be supplied to the arc furnace within a time window while satisfying all currently permissible threshold values is determined based on the result of the comparison.

The metallurgical furnace comprises a closed vessel enclosing a reducing atmosphere. The vessel comprises at least one electrode providing energy to a burden. The burden comprises a body of molten metal having an upper surface. A carbon injecting lance, in an operational position thereof, extends from an inlet end thereof outside the vessel through a port in the vessel to an outlet end thereof inside the vessel where the lance terminates below the upper surface. The inlet end is connected to a source of carbon. The lance being movable between the operational position and a retracted position wherein the outlet end is outside the vessel. The furnace further comprises a gastight enclosure for the lance when in the retracted position. The enclosure locates on the vessel in gastight manner and over the port and maintains the reducing atmosphere in the vessel.

A molten pig iron manufacturing method using a fixed-type DC electric furnace, wherein an auxiliary raw material is supplied to the fixed-type DC electric furnace and molten pig iron having a C concentration of 2 to 4 mass % at a temperature of 1400 C. to 1550 C. is tapped from a tap hole in a state in which a solid iron source is present in the furnace inner peripheral wall space and in a state in which the solid iron source is not present in the upper electrode facing space.

A method for producing a high purity high carbon molten chrome product from chrome and carbon bearing material, said method comprising the steps of: (a) continuously introducing chrome compacts directly into an electric melter; (b) heating and melting the chrome compacts in the electric melter at a temperature of between about 1300 C. to about 1700 C. to form high carbon molten chrome; (c) preventing oxidation of the high carbon molten chrome via minimization of the ingress of oxygen containing gas in said heating step; (d) carburizing the high carbon molten chrome to form high carbon molten metallized chrome; (e) purifying the high carbon molten metallized chrome by reducing silicon oxides to silicon and desulfurizing the high carbon molten metallized chrome to produce the high purity high carbon molten chrome product; and (f) discharging the high purity high carbon molten chrome product from the electric melter.

The invention provides a maraging steel production method in which an oxide is added during an Mg oxide formation step, the production method including: the Mg oxide formation step in which Mg is added to molten steel and MgO is formed in the molten steel, during primary melting; a consumable electrode production step in which, after the Mg oxide formation step, the molten steel is solidified and a consumable electrode having residual MgO is obtained; and a vacuum arc re-melting step in which the consumable electrode is used and vacuum arc re-melting is performed.

In an electric arc furnace system for making steel, a method and structure (1) for eliminating teeming hang-ups and ensuring temperature homogeneity in a ladle which teems into an ingot mold by gas purging at all possible steps under both atmospheric and vacuum conditions, and (2) for preventing non-metallic inclusions from appearing in the final product by deflecting the granular material in the teeming ladle well block away from the ingot mold by a heat resistant but combustible deflector just prior to entry of the teeming stream into the ingot mold.