Arc Steel Furnace

In the designation of an arc steel furnace, as a rule, its capacity in tons is present (for example, DSP-12). The range of furnaces varies from 1 to 400 tons . Particleboard temperatures can reach 1800 ° C.

An arc steel-smelting furnace (DSP) consists of a melting bath (working space), an arc power regulator and auxiliary technological mechanisms that allow opening (closing) the furnace arch, collect slag and release molten metal.

The power of the electric arc is regulated by a software-adaptive controller, which, with the help of the drive, moves the electrodes in a vertical plane. Known electric arc regulators with an electromechanical drive, which, due to their inertia, are not widely used and are now almost completely supplanted by electro-hydraulic controllers.

As a rule, a chipboard has individual power supply through the so-called “furnace” transformer connected to a high-voltage power line. The power of the transformer can reach 300 MVA. Its secondary voltage is in the range from 50 to 300 V (in modern furnaces up to 1200 V), and the primary voltage is from 6 to 35 kV (for high-power furnaces up to 110 kV). Secondary voltage is regulated by means of a step switch, which maintains its functionality also in the melting mode.

Steel is melted in the working space of the furnace, which is bounded from above by a dome-shaped arch, from below and from the sides, respectively, by a spherical hearth and walls, the casing of which is lined with refractory material from the inside. The removable vault may be composed of refractory bricks resting on a support ring, or, like the walls of the furnace, may be made of water-cooled panels. Through three holes symmetrically located in the arch, conductive graphite electrodes are introduced into the working space, which can be moved up and down using special mechanisms. The furnace is usually powered by a three-phase electric current, and there are also direct current furnaces. A modern powerful arc furnace is mainly used as a unit for melting the mixture and producing a liquid intermediate, which is further processed to the required chemical composition.

For the first time in the world, the possibility of using an arc for melting metals was shown by V.V. Petrov in 1803. Petrov showed that with the help of such an arc one can not only melt metals, but also reduce them from oxides by heating them in the presence of carbonaceous reducing agents. In addition, he managed to obtain the welding of metals in an electric arc.

In 1810, Sir Humphrey Davy conducted an experimental demonstration of arc burning. In 1853, Pichon tried to build an electrothermal furnace. In the years 1878-79, Sir Wilhelm Siemens received a patent for an electric arc furnace. In 1899, the first direct-acting arc furnace was built by Eru .

Although particleboard was used during World War II to produce steel alloys, it became widespread only after its completion.

Smelting in chipboard, after inspecting the furnace and repairing the affected areas of the lining (refueling), begins with filling the charge . In modern furnaces, the mixture is loaded from above using a loading bucket (basket). To protect the hearth from impacts in large pieces of the mixture, small scrap is loaded onto the bottom of the tub. For early slag formation, 2-3% of the mass of the metal charge is introduced into the filling. After filling, the electrodes are lowered into the furnace, the high-voltage switch is turned on and the melting period begins. At this stage, a breakdown of the electrodes is possible (in case of poor conductivity between the electrode and the charge, the electric arc disappears and the electrode abuts against a non-conductive piece of the charge). The control of the power output is carried out by changing the position of the electrodes (length of the electric arc ) or voltage on the electrodes. After a period of melting in the furnace, a layer of metal and slag is formed . Slag is downloaded through the slag notch (working window), constantly sitting slag-forming, throughout the entire period of melting, in order to remove phosphorus from the melt. The slag is foamed with carbon-containing materials to close the arcs, for its better downloadability and reduce the loss of metal.

Finished steel and slag are discharged into the steel ladle through the steel outlet and the chute by tilting the working space (or, if the furnace is equipped with a bottom outlet instead of the chute, then through it). The working window, closed by a shutter, is designed to monitor the progress of melting (measuring the temperature of the metal and sampling the chemical composition of the metal). Also, the working window can be used to supply slag-forming and alloying materials (on small furnaces). On modern heavy-duty furnaces, the supply of slag-forming during melting is carried out through a special hole in the arch of the conveyor feed. Carbonaceous materials for foaming slag are fed into the furnace either in portions through the arch or are injected by injection burners with a stream of compressed air. Before the release and during the release, alloying and deoxidizing agents are added to the steel ladle, and slag-forming materials are also added when cutting off furnace slag.

The use of electric energy (electric current), the ability to melt a charge (scrap) of almost any composition, precise control of the temperature of the metal and its chemical composition prompted the industry to use chipboard during the Second World War for the production of alloy steel, high-quality casting and, as a result, weapon parts and ammunition . Today, arc steel-smelting furnaces produce various grades of steels and cast irons, and can also be a source of raw materials (intermediate) for ACP and CCM .

High local overheating under the electrodes; the difficulty of mixing and averaging the chemical composition of steel; significant amount of combustion products and noise during operation.

The main tasks of automated control of the smelting process are:

1. Centralized control of the technological process and operation of the furnace with the issuance of information about registration and signaling deviations from the set values.
2. Process control.
3. Energy management, ensuring maximum use of the furnace power.
4. Support operations management.
5. Collection and selection of information with the issuance of the necessary documentation.
6. Monitoring the operation of equipment with alarm and fault reporting ^[1] .

• Electron beam melting
• Electric resistance furnace
• Induction crucible furnace
• Muffle furnace
• Blast furnace
• Open hearth furnace
• AKP (Bucket-Furnace Unit)
• Caster

• Svenchansky A. D., Smelyansky M. Ya. Electric industrial furnaces. - M .: 1970.
• Lebedev I.A.,. Electric furnace // Brockhaus and Efron Encyclopedic Dictionary : in 86 volumes (82 volumes and 4 additional). - SPb. , 1890-1907.
• Linchevsky B.V., Sobolevsky A.L., Kalmenev A.A. Metallurgy of ferrous metals. - M .: 1986.
• Sapko A.I. Executive mechanisms of power regulators of electric arc furnaces. M., Energy, 1969. - 128 p.