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An electric arc furnace is a system that heats charged material by means of an electric arc. Image File history File links No higher resolution available. ... Electricity arcs between the power rail and electrical pickup shoe on a London Underground train An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, similar to the instant spark, resulting from a current flowing through normally nonconductive media such as air. ...

Arc furnaces range in size from small units of approximately one ton capacity (used in foundries for producing cast iron products) up to about 400 ton units used for secondary steelmaking. Arc furnaces used in research laboratories and by dentists may have a capacity of only a few dozen grams. Temperatures inside an electric arc furnace can rise to 1,800 degrees Celsius. A furnace is a device for heating air or any other fluid. ... Look up ton in Wiktionary, the free dictionary. ... A foundry is a factory which produces castings of metal, both ferrous and non-ferrous. ... Cast iron usually refers to grey cast iron, but can mean any of a group of iron-based alloys containing more than 2% carbon (alloys with less carbon are carbon steel by definition). ... Steelmaking is the second step in producing steel from iron ore. ... A Dentist and Dental Assistant perform surgery on a patient. ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ...

History

Steel mill with two arc furnaces

The first electric arc furnaces were developed by Paul Héroult, of France, with a commercial plant established in the United States in 1907. Initially "electric steel" was a specialty product for such uses as machine tools and spring steel. Arc furnaces were also used to prepare calcium carbide for use in carbide lamps. Image File history File links Size of this preview: 800 × 448 pixelsFull resolution (825 × 462 pixel, file size: 95 KB, MIME type: image/jpeg) The Finkl steel mill on Cortland Author: paytonc @ Flickr File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to... Image File history File links Size of this preview: 800 × 448 pixelsFull resolution (825 × 462 pixel, file size: 95 KB, MIME type: image/jpeg) The Finkl steel mill on Cortland Author: paytonc @ Flickr File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to... The French scientist Paul (Louis-Toussaint) Héroult (1863-1914) was the inventor of the aluminium electrolysis and of the electric steel furnace. ... Year 1907 (MCMVII) was a common year starting on Tuesday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Monday of the 13-day-slower Julian calendar). ... A machine tool is a powered mechanical device, typically used to fabricate metal components of machines by the selective removal of metal. ... Martensite, named after the German metallurgist Adolf Martens, is a class of hard minerals occurring as lathe- or plate-shaped crystals. ... Calcium carbide is a chemical compound with the chemical formula CaC2. ... Lit carbide lamp Carbide lamp on a bicycle Carbide lamps (acetylene lamps) are simple lamps that produce and burn acetylene (C2H2) gas produced by reacting calcium carbide (CaC2) with water. ...

In the 19th century, a number of men had employed an electric arc to melt iron. Sir Humphry Davy conducted an experimental demonstration in 1810; welding was investigated by Pepys in 1815; Pinchon attempted to create an electrothermic furnace in 1853; and, in 1878 - 79, Sir William Siemens took out patents for electric furnaces of the arc type. The Stessano electric furnace is an arc type furnace that usually rotates to mix the bath. The Girod furnace is similar to the Héroult furnace. Alternative meaning: Nineteenth Century (periodical) (18th century — 19th century — 20th century — more centuries) As a means of recording the passage of time, the 19th century was that century which lasted from 1801-1900 in the sense of the Gregorian calendar. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Standard atomic weight 55. ... Sir Humphry Davy, 1st Baronet, FRS (17 December 1778 – 29 May 1829) was an esteemed British chemist and physicist. ... 1810 was a common year starting on Monday (see link for calendar). ... April 5-12: Mount Tambora explodes, changing climate. ... 1853 was a common year starting on Saturday (see link for calendar). ... 1878 (MDCCCLXXVIII) was a common year starting on Tuesday (see link for calendar). ... 1879 (MDCCCLXXIX) was a common year starting on Wednesday (see link for calendar). ... Wilhelm Siemens Carl Wilhelm Siemens (en: Charles William Siemens) (April 4, 1823 – November 19, 1883) was a German engineer. ... A patent is a set of exclusive rights granted by a state to a patentee for a fixed period of time in exchange for a disclosure of an invention. ...

Different from the arc type of electrothermic furnace is the induction type furnace. The Kjellin furnace and the Röchling-Rodenhauser furnace are two. The Grönwall furnace produced steel at Trollhattan, in Scandinavia. An induction furnace is an electrical furnace in which the heat is applied by induction heating of a conductive medium (usually a metal) in a crucible around which magnetic coils are wound. ... Waterfalls in Trollhättan Trollhättan is a Municipality in Västra Götaland County, in western Sweden. ... Scandinavia is a historical and geographical region centered on the Scandinavian Peninsula in Northern Europe and includes the three kingdoms of Denmark, Norway and Sweden. ...

While EAFs were widely used in World War II for production of alloy steels, it was only afterwards that electric steelmaking began to expand. The low capital cost for a mini-mill - around US$140-200 per ton of annual installed capacity, compared with US$1,000 per ton of annual installed capacity for an integrated steel mill - allowed mills to be quickly set up in war-ravaged Europe, and also allowed them to successfully compete with the big United States steelmakers, such as Bethlehem Steel and U.S. Steel, for low-cost, carbon steel 'long products' (structural steel, rod and bar, wire and fasteners) in the U.S. market. When Nucor - now one of the largest steel producers in the U.S.^{[citation needed]} - decided to enter the long products market in 1969, they chose to start up a mini-mill, with an EAF as its steelmaking furnace, soon followed by other manufacturers. Whilst Nucor expanded rapidly up and down the Eastern U.S., the companies that followed them into mini-mill operations concentrated on local markets for long products, where the use of an EAF allowed the plants to be flexible with production, according to local demand. This pattern was also followed in countries around the world, with EAF steel production primarily used for long products, while integrated mills, using blast furnaces and basic oxygen furnaces, cornered the markets for flat products - sheet steel and plate. In 1987, Nucor made the decision to expand into the flat products market, still using the EAF production route. The fact that an EAF uses scrap steel as feedstock, instead of raw iron, has impacted on the quality of the flat product made from EAF steel, because of the limited amount of control over the impurities that are contained within the scrap. A steel mill at the turn of the century in Pittsburgh, Pennsylvania A steel mill (British English and Australian English steelworks) is an industrial plant for the manufacture of steel. ... Look up ton in Wiktionary, the free dictionary. ... A steel mill at the turn of the century in Pittsburgh, Pennsylvania A steel mill (British English and Australian English steelworks) is an industrial plant for the manufacture of steel. ... Bethlehem Steel Corporations flagship manufacturing facility in Bethlehem, Pennsylvania, in the United States. ... The United States Steel Corporation NYSE: X is an integrated steel producer with major production operations in the United States and Central Europe. ... Carbon steel, also called plain carbon steel, is a metal alloy, a combination of two elements, iron and carbon, where other elements are present in quantities too small to affect the properties. ... Structural steel is steel construction material, a profile, formed with a specific shape and certain standards of chemical composition and strength. ... This article or section does not adequately cite its references or sources. ... A fastener is a hardware device that mechanically joins or affixes two or more objects together. ... Nucor Corporation (NYSE: NUE) is one of the largest steel producers in the United States, and the largest of the mini-mill operators (those using electric arc furnaces to melt scrap steel, as opposed to companies using traditional blast furnace technology). ... Blast furnace in Sestao, Spain. ... The basic oxygen furnace is the place within a foundry where molten iron from the blast furnace is changed into liquid steel. ... Sheets of stainless steel cover the Chrysler Building Thin sheets of gold leaf Sheet metal is simply metal formed into thin and flat pieces. ... Plate has several meanings: A plate electrode in a vacuum tube. ...

Construction

An electric arc furnace used for steelmaking consists of a refractory-lined vessel, usually water-cooled in larger sizes, covered with a retractable roof, and through which one or more graphite electrodes enter the furnace. The furnace is primarily split into three sections: the shell, which consists of the sidewalls and lower steel 'bowl'; the hearth, which consists of the refractory that lines the lower bowl; and the roof, which may be refractory-lined or water-cooled, and can be shaped as a section of a sphere, or as a frustum (conical section). The roof also supports the refractory delta in its centre, through which one or more graphite electrodes enter. The hearth may be hemispherical in shape, or in an eccentric bottom tapping furnace (see below), the hearth has the shape of a halved egg. In modern meltshops, the furnace is often raised off the ground floor, so that ladles and slag pots can easily be manoeuvered under either end of the furnace. Separate to the furnace structure is the electrode support and electrical system, and the tilting platform on which the furnace rests. Two configurations are possible: the electrode supports and the roof tilt with the furnace, or are fixed to the raised platform. The term refractory can refer to multiple things: A refractory clergyman is one who refused to swear an oath to the French Revolution-era French state under the Civil Constitution of the Clergy. ... Graphite (named by Abraham Gottlob Werner in 1789 from the Greek γραφειν (graphein): to draw/write, for its use in pencils) is one of the allotropes of carbon. ... An electrode is an electrical conductor used to make contact with a metallic part of a circuit (e. ... A sphere is a perfectly symmetrical geometrical object. ... A frustum is the portion of a solid â€“ normally a cone or pyramid â€“ which lies between two parallel planes cutting the solid. ... Graphite (named by Abraham Gottlob Werner in 1789 from the Greek γραφειν (graphein): to draw/write, for its use in pencils) is one of the allotropes of carbon. ... LADLE ...

A typical alternating current furnace has three electrodes. Electrodes are round in section, and typically in segments with threaded couplings, so that as the electrodes wear, new segments can be added. The arc forms between the charged material and the electrode, and the charge is heated both by current passing through the charge and by the radiant energy evolved by the arc. The electrodes are automatically raised and lowered by a positioning system, which may use either electric winch hoists or hydraulic cylinders. The regulating system maintains an approximately constant current and power input during the melting of the charge, even though scrap may move under the electrodes while it melts. The mast arms holding the electrodes carry heavy busbars, which may be hollow water-cooled copper pipes, used to convey current to the electrode holders. Modern systems use 'hot arms', where the whole arm carries the current, increasing efficiency. These can be made from copper-clad steel or aluminium. Since the electrodes move up and down automatically for regulation of the arc, and are raised to allow removal of the furnace roof, heavy water-cooled cables connect the bus tubes/arms with the transformer located adjacent to the furnace. To protect the transformer from the heat of the furnace, it is installed in a vault. City lights viewed in a motion blurred exposure. ... Three-phase power transformer which is the sole transfer point for electricity to a suburban shopping mall in Canada. ... Modern self-tailing winch on a sailing boat. ... This page is a candidate for speedy deletion. ... 1500 amp busbars within a power distribution rack for a large building A busbar (often pronounced buzz bar) refers in electrical power distribution to thick strips of Copper or other material that conduct electricity around a switchboard or distribution board. ... General Name, Symbol, Number copper, Cu, 29 Chemical series transition metals Group, Period, Block 11, 4, d Appearance metallic pinkish red Standard atomic weight 63. ... General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Standard atomic weight 26. ... A cable is two or more wires or optical fibers bound together, typically in a common protective jacket or sheath. ... Three-phase pole-mounted step-down transformer. ...

The furnace is built on a tilting platform so that the liquid steel can be poured into another vessel for transport in the steel making process. The operation of tilting the furnace to pour off molten steel is called "tapping". Originally, all steelmaking furnaces had a tapping spout closed with refractory that washed out when the furnace was tilted, but often modern furnaces have an eccentric bottom tap-hole (EBT) to reduce inclusion of nitrogen and slag in the liquid steel, with the taphole set in the 'nose' of the egg-shaped hearth. Modern plants may have two shells with a single set of electrodes that can be transferred between the two; one shell preheats scrap while the other shell is utilised for meltdown. Other DC-based furnaces have a similar arrangement, but have electrodes for each shell and one set of electronics. Eccentric is from the Greek for out of the centre, as opposed to concentric, in the centre. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... Slag is also an early play by David Hare. ...

A mid-sized modern steelmaking furnace would have a transformer rated about 60,000,000 volt-amperes (60 MVA), with a secondary voltage between 400 and 900 volts and a secondary current in excess of 44,000 amperes. In a modern shop such a furnace would be expected to produce a quantity of 80 metric tonnes of liquid steel in approximately 60 minutes from charging with cold scrap to tapping the furnace. In comparison, basic oxygen furnaces can have a capacity of 150-300 tonnes per batch, or 'heat', and can produce a heat in 30-40 minutes. Enormous variations exist in furnace design details and operations, depending on the end product and local conditions, as well as ongoing research to improve furnace efficiency - the largest furnace (in terms of tapping weight and transformer rating) is in Turkey, with a tap weight of 350 metric tonnes and a transformer of 350 MVA. Three-phase pole-mounted step-down transformer. ... The basic oxygen furnace is the place within a foundry where molten iron from the blast furnace is changed into liquid steel. ...

To produce a ton of steel in an electric arc furnace requires on the close order of 400 kilowatt-hours per short ton of electrical energy, or about 440kWh per metric tonne; the theoretical minimum amount of energy required to melt a tonne of scrap steel is 300kWh (melting point 1520°C/2768°F). Electric arc steelmaking is only economical where there is a plentiful supply of electric power, with a well-developed electrical grid. The kilowatt-hour (symbol: kW·h) is a unit for measuring energy. ... The short ton is a unit of mass equal to 907. ... A tonne (also called metric ton) is a non-SI unit of mass, accepted for use with SI, defined as: 1 tonne = 103 kg (= 106 g). ...

Operation

• Scrap metal is delivered to a scrap bay, located next to the melt shop. Scrap generally comes in two main grades: shred (scrap light enough to have been passed through a shredder) and heavy melt (large slabs and beams), along with some direct reduced iron (DRI) or pig iron for chemical balance. Some furnaces, however, melt almost 100% DRI.

• The scrap is loaded into large buckets called baskets, with 'clamshell' doors for a base. Care is taken to layer the scrap in the basket to ensure good furnace operation; heavy melt is placed on top of a light layer of protective shred, on top of which is placed more shred. These layers should be present in the furnace after charging. After loading, the basket may pass to a scrap pre-heater, which uses hot furnace off-gases to heat the scrap and recover energy to increase plant overall efficiency.

• The scrap basket is then taken to the melt shop, the roof is swung off the furnace, and the furnace is charged with scrap from the basket. Charging is one of the more dangerous operations for the EAF operators. There is a lot of energy generated by multiple tonnes of falling metal; any liquid metal in the furnace is often displaced upwards and outwards by the solid scrap, and the grease and dust that coats the scrap is ignited if the furnace is hot, resulting in a fireball erupting out of the top of the furnace and the slag door. In some twin-shell furnaces, the scrap is charged into the second shell while the first is being melted down, and pre-heated with off-gas from the active shell. Other operations are continuous charging - pre-heating scrap on a conveyor belt, which then discharges the scrap into the furnace proper, or charging the scrap from a shaft set above the furnace, with off-gases directed through the shaft. Yet other furnaces can be charged with hot (molten) metal from other operations.

• After charging, the roof is swung back over the furnace and meltdown commences. The electrodes are lowered onto the scrap, an arc is struck and the electrodes are then set to bore into the layer of shred at the top of the furnace. Lower voltages are selected for this first part of the operation to protect the roof and walls from excessive heat and damage from the arcs. Once the electrodes have reached the heavy melt at the base of the furnace and the arcs are shielded by the scrap, the voltage can be increased and the electrodes raised slightly, lengthening the arcs and increasing power to the melt. This enables a molten pool to form more rapidly, reducing tap-to-tap times. In more modern furnaces, oxygen is also lanced into the scrap, combusting or cutting the steel and burning out carbon, and sometimes chemical heat is provided by wall-mounted oxy-fuel burners. Both processes accelerate scrap meltdown.

• An important part of steelmaking is the formation of slag, which floats on the surface of the molten steel. Slag usually consists of metal oxides, and acts as a destination for oxidised impurities, as a thermal blanket (stopping excessive heat loss) and helping to reduce erosion of the refractory lining. For a furnace with basic refractories, which includes most carbon steel-producing furnaces, the usual slag formers are calcium oxide (CaO, in the form of burnt lime) and magnesium oxide (MgO, in the form of dolomite and magnesite). These slag formers are either charged with the scrap, or blown into the furnace during meltdown. Later in the heat, carbon (in the form of coke) is lanced into this slag layer, partially combusting to form carbon monoxide gas, which then causes the slag to foam, allowing greater thermal efficiency, and better arc stability and electrical efficiency. The slag blanket also covers the arcs, prevents damage to the furnace roof and sidewalls from radiant heat.

• Once flat bath conditions are reached, i.e. the scrap has been completely melted down, often another bucket of scrap is charged into the furnace and melted down. After the second charge is completely melted, refining operations take place to check and correct the steel chemistry and superheat the melt above its freezing temperature in preparation for tapping. More slag formers are introduced and more oxygen is lanced into the bath, burning out impurities such as silicon, sulphur, phosphorus, aluminium, manganese and calcium and removing their oxides to the slag. Metals that have a poorer affinity for oxygen than iron, such as nickel and copper, cannot be removed through oxidation and must be controlled through scrap chemistry alone, such as introducing the direct reduced iron and pig iron mentioned earlier. A foaming slag is maintained throughout, and often overflows the furnace to pour out of the slag door into the slag pit. Temperature sampling and chemical sampling (in the form of a 'chill' - a small, solidified sample of the steel) take place via automatic lances.

• Once the temperature and chemistry are correct, the steel is tapped out into a preheated ladle through tilting the furnace. As soon as slag is detected during tapping the furnace is rapidly tilted back towards the deslagging side, minimising slag entering the ladle. During tapping some alloy additions are introduced into the metal stream. Often, a few tonnes of liquid steel and slag is left in the furnace in order to form a 'hot heel', which helps preheat the next charge of scrap and accelerate its meltdown. During and after tapping, the furnace is 'turned around': the slag door is cleaned of solidified slag, repairs may take place, and electrodes are inspected for damage or lengthened through the addition of new segments; the taphole is filled with sand at the completion of tapping. For a 90-tonne, medium-power furnace, the whole process will usually take about 60-70 minutes from the tapping of one heat to the tapping of the next (the tap-to-tap time).

A breakers yard in the UK, showing cars stacked on a metal grid to make it easier to find and remove usable parts. ... Direct reduced iron is an ore concentrate produced from iron ore powder by use of large quantities of natural gas. ... Pig iron is raw iron, the immediate product of smelting iron ore with coke and limestone in a blast furnace. ... Potential energy is the energy that is by virtue of the relative positions (configurations) of the objects within a physical system. ... Look up grease in Wiktionary, the free dictionary. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ... Slag is also an early play by David Hare. ... An oxide is a chemical compound containing an oxygen atom and other elements. ... The term refractory can refer to multiple things: A refractory clergyman is one who refused to swear an oath to the French Revolution-era French state under the Civil Constitution of the Clergy. ... Acids and bases: Acid-base reaction pH Self-ionization of water Buffer solutions Systematic naming Acid-base extraction Acidity function Proton affinity Acids: Strong acids Weak acids Superacids Lewis acids Mineral acids Organic acids Bases: Strong bases Weak bases Superbases Lewis bases Organic bases edit In chemistry, a base is... Carbon steel, also called plain carbon steel, is a metal alloy, a combination of two elements, iron and carbon, where other elements are present in quantities too small to affect the properties. ... Calcium oxide (CaO), commonly known as lime, quicklime or burnt lime, is a widely used chemical compound. ... This article or section does not adequately cite its references or sources. ... Magnesium oxide, or magnesia, is a white solid mineral that occurs naturally as periclase and is a source of magnesium. ... Dolomite crystals from Touissite, Morocco Dolomite is the name of both a carbonate rock and a mineral consisting of calcium magnesium carbonate (formula: CaMg(CO3)2) found in crystals. ... Magnesite is magnesium carbonate, MgCO3. ... Coke Coke is a solid carbonaceous material derived from destructive distillation of low-ash, low-sulfur bituminous coal. ... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ... Sea foam on the beach. ... The thermal efficiency () is a dimensionless performance measure of a thermal device such as an internal combustion engine, a boiler, or a furnace, for example. ... The efficiency of an entity (a device, component, or system) in electronics and electrical engineering is defined as useful power output divided by the total electrical power consumed (a fractional expression). ... It has been suggested that Silicons ranking be merged into this article or section. ... For the chemical element see: sulfur. ... General Name, Symbol, Number phosphorus, P, 15 Chemical series nonmetals Group, Period, Block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ... General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Standard atomic weight 26. ... General Name, Symbol, Number manganese, Mn, 25 Chemical series transition metals Group, Period, Block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... General Name, Symbol, Number calcium, Ca, 20 Chemical series alkaline earth metals Group, Period, Block 2, 4, s Appearance silvery white Standard atomic weight 40. ... General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10, 4, d Appearance lustrous, metallic and silvery with a gold tinge Standard atomic weight 58. ... General Name, Symbol, Number copper, Cu, 29 Chemical series transition metals Group, Period, Block 11, 4, d Appearance metallic pinkish red Standard atomic weight 63. ... The most fundamental reactions in chemistry are the redox processes. ...

Advantages of electric arc furnace for steelmaking

The precise control of chemistry and temperature encouraged use of electric arc furnaces during World War II for production of steel for shell casings. Today steelmaking arc furnaces produce many grades of steel, from concrete reinforcing bars and common merchant-quality standard channels, bars, and flats to special bar quality grades used for the automotive and oil industry. Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... A M4 Carbine just after firing, with an ejected case in mid-air The article titled casing is a disambiguation page. ... Concrete being poured, raked and vibrated into place in residential construction in Toronto, Ontario, Canada. ... A tied rebar beam cage. ...

A typical steelmaking arc furnace is the source of steel for a mini-mill, which may make bars or strip product. The steelmaking arc furnace is generally charged with scrap steel, though if hot metal from a blast furnace or direct-reduced iron is available economically, these can also be used for steelmaking. A steel mill at the turn of the century in Pittsburgh, Pennsylvania A steel mill (British English and Australian English steelworks) is an industrial plant for the manufacture of steel. ... Blast furnace in Sestao, Spain. ...

Environmental issues

Although the modern electric arc furnace is a highly efficient recycler of steel scrap, operation of an arc furnace shop can have adverse environmental effects. Much of the capital cost of a new installation will be devoted to systems intended to reduce these effects, which include: A breakers yard in the UK, showing cars stacked on a metal grid to make it easier to find and remove usable parts. ...

• High sound levels
• Dust and off-gas production
• Slag production
• Cooling water demand
• Heavy truck traffic for scrap, materials handling, and products
• Environmental effects of electricity generation

Because of the very dynamic quality of the arc furnace load, power systems may require technical measures to maintain the quality of power for other customers; flicker and harmonic distortion are common side-effects of arc furnace operation on a power system. Slag is also an early play by David Hare. ...

Other electric arc furnaces

For steelmaking, direct current (DC) arc furnaces are used, with a single electrode in the roof and the current return through a conductive bottom lining or conductive pins in the base. The advantage of DC is lower electrode consumption per ton of steel produced, since only one electrode is used, as well as less electrical harmonics and other similar problems. However, the size of DC arc furnaces is limited by the available electrodes and maximum allowable voltage. Maintenance of the conductive furnace hearth is a bottleneck in extended operation of a DC arc furnace. Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ...

In a steel plant, a ladle furnace can be used to maintain the temperature of liquid steel during processing after tapping from the scrap-melting furnace. This also allows the molten steel to be kept ready for use in the event of a delay later in the steelmaking process. The ladle furnace consists of only the refractory roof and electrode system of a scrap-melting furnace, but it has no need for a tilting mechanism or scrap charging.

Electric arc furnaces are also used for production of non-ferrous alloys, and for production of phosphorus. Furnaces for these services are physically different from steel-making furnaces and may operate on a continuous, rather than batch, basis. Continuous process furnaces may also use paste-type (Soderberg) electrodes to prevent interruptions due to electrode changes. Such furnaces are usually known as submerged arc furnaces, because the electrode tips are buried in the slag/charge, and arcing occurs through the slag, between the matte and the electrode. A steelmaking arc furnace, by comparison, arcs in the open. The key is the electrical resistance, which is what generates the heat required: the resistance in a steelmaking furnace is the atmosphere, while in a submerged arc furnace, the slag or charge forms the resistance. The liquid metal formed in either furnace is too conductive to form an effective heat-generating resistance. An alloy is a homogeneous mixture of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. ... General Name, Symbol, Number phosphorus, P, 15 Chemical series nonmetals Group, Period, Block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ... Matte refers to the following: the surface surrounding a framed picture, between the picture itself and the frame; usually made from coloured card a surface with a non-glossy finish (also matt or mat) a filmmaking technique a smelted sulfide material in extractive metallurgy a form of the name Matthew... Electrical resistance is a measure of the degree to which an electrical component opposes the passage of current. ...

Amateurs have constructed a variety of arc furnaces, often based on electric arc welding kits contained by silical blocks or flower pots. Though crude, these simple furnaces are capable of melting a wide range of materials and creating calcium carbide etc. Calcium carbide is a chemical compound with the chemical formula CaC2. ...

References

• H. W. Beaty (ed), "Standard Handbook for Electrical Engineers,11th Ed.", McGraw Hill, New York 1978, ISBN 0-07-020974-X
• J.A.T. Jones, B. Bowman, P.A. Lefrank, Electric Furnace Steelmaking, in The Making, Shaping and Treating of Steel, R.J. Fruehan, Editor. 1998, The AISE Steel Foundation: Pittsburgh. p. 525-660.

External links

• Recognition of first foundry as historical site
• Home made small scale arc furnace using a welder (Caution with experiments!)
• Electric Arc Furnace module at steeluniversity.org, including a fully interactive simulation