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EP0063711B1 - Elektrode für Lichtbogenöfen und deren Verwendung - Google Patents

Elektrode für Lichtbogenöfen und deren Verwendung Download PDF

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Publication number
EP0063711B1
EP0063711B1 EP82102771A EP82102771A EP0063711B1 EP 0063711 B1 EP0063711 B1 EP 0063711B1 EP 82102771 A EP82102771 A EP 82102771A EP 82102771 A EP82102771 A EP 82102771A EP 0063711 B1 EP0063711 B1 EP 0063711B1
Authority
EP
European Patent Office
Prior art keywords
electrode according
several
electrode
bottom portion
carbon material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP82102771A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0063711A1 (de
Inventor
Dieter H. Dr. Dipl.-Chem. Zöllner
Inge Dr. Dipl.-Chem. Lauterbach-Dammler
Franz Schieber
Friedrich Rittmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Arc Technologies Systems Ltd
Original Assignee
Arc Technologies Systems Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Arc Technologies Systems Ltd filed Critical Arc Technologies Systems Ltd
Priority to AT82102771T priority Critical patent/ATE15120T1/de
Publication of EP0063711A1 publication Critical patent/EP0063711A1/de
Application granted granted Critical
Publication of EP0063711B1 publication Critical patent/EP0063711B1/de
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/06—Electrodes
    • H05B7/08—Electrodes non-consumable
    • H05B7/085—Electrodes non-consumable mainly consisting of carbon
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/10—Mountings, supports, terminals or arrangements for feeding or guiding electrodes
    • H05B7/101—Mountings, supports or terminals at head of electrode, i.e. at the end remote from the arc

Definitions

  • the invention relates to an electrode for arc furnaces made of an upper section made of metal and an edible lower section made of carbon material, which have a substantially cylindrical shape and are connected to one another by a screw nipple or the like or else directly, the upper section having a liquid cooling device has a flow channel and a return channel and the upper section can preferably be protected in its lower area by a high-temperature-resistant coating, and their use.
  • Arc furnaces for the production of electrical steel, copper, corundum, cobalt, silicon etc. have so far been operated with graphite electrodes as current-carrying elements.
  • An electrode string is usually composed of a plurality of graphite units which are connected to one another by screw connections or the like. Three electrode strands are often used as current-carrying elements per furnace for these electrothermal high-temperature melting processes.
  • electrodes for electric arc furnaces have been described in DE-A-1 565 751, which consist of an upper metallic head piece, a lower metallic head piece, both electrical conductors connecting to one another, a ceramic mass including these conductors and the lower head piece, and one lower head piece consist of replaceable attached electrode tip.
  • a liquid-cooled electrode is also known from DE-A-2 845 367, which has a cylindrical clamping part fastened to the electrode support arm, a metallic cooling system fastened to it and guiding the electrode current and carrying a threaded part at the free end for screwing on the electrode tip, and a tubular heat shield , which contains the cooling system in the area exposed to the furnace atmosphere at a distance and in a fixed spatial association therewith.
  • EP-A-12 573 discloses a combination electrode in which the laterally external metallic contact of the metal shaft is mounted in an insulating manner with respect to the internal metallic cooling system.
  • a ceramic coating secured with hooks is provided, which extends to approximately the height of the screw nipple connection with which a carbon part is attached.
  • the invention is therefore based on the object of providing an electrode for arc furnaces of the type mentioned at the outset, in which the metal shaft and carbon material are matched to one another in such a way that the electrode can be operated in a manner which is less susceptible to faults.
  • this is intended to reduce electrode downtime and simplify the manufacturing process for the carbon parts that form the lower section of the electrode.
  • This object is achieved by creating an electrode of the type mentioned at the outset, which is characterized in that the lower section is formed from fine-grained, high-strength, highly graphitic carbon material with a bulk density of at least 1.70 g / cm 3 .
  • the lower section is connected to the upper section of metal generally by a nipple made of metal such as cast iron or copper, but preferably graphite.
  • a nipple made of metal such as cast iron or copper, but preferably graphite.
  • another type of fastening with the upper section made of metal can also be selected, if necessary.
  • This is provided with a liquid cooling device, which is usually formed from at least one flow and one return channel. With its inlet channel, the cooling device preferably also reaches the upper outer region of the nipple, which is particularly preferred. Alternatively, it is also possible to flow through the nipple with the cooling system itself, if necessary.
  • the upper section extends over 40 to 80%, preferably 60 to 80%, of the total length of the electrode.
  • the advantages of the invention are achieved when the lower section is formed from fine-grained, high-strength, highly graphitic carbon material with a bulk density of at least 1.70 g / cm 3 , particularly advantageous results are obtained with bulk densities in the range from 1.75 to 1 , 92 g / cm 3 reached. The use of the latter carbon materials is therefore particularly favorable.
  • the carbon material which forms the lower section of the electrode according to the invention can have a specific electrical resistance of less than 6 ⁇ mm 2 / m.
  • the carbon material has a thermal conductivity of more than 200 W / mK.
  • the fine-grained, high-strength, highly graphitic carbon material forming the lower section can advantageously be chosen such that the bending strength is more than 15 N / mm 2 .
  • An electrode of the type mentioned at the outset is therefore particularly advantageous in which the lower section made of fine-grained, highly graphitic carbon material has a bulk density of 1.75 to 1.92 g / cm 3 , a specific electrical resistance of: 5 6 Q mm 2 / m, has a thermal conductivity of> 200 W / mK and a flexural strength of more than 15 N / mm 2 .
  • carbon material with a maximum grain size of 1 to 3 mm is used with particular advantage.
  • the carbon material used in the lower section of the electrode according to the invention can be produced particularly cheaply from high-quality premium coke using binding and impregnating agents.
  • particularly good lower sections are obtained at a graphitization temperature above 2900 ° C.
  • the diameter of the lower section is smaller than that of the upper section made of metal and also smaller than that of full graphite electrodes for a given load.
  • the diameter of the lower section is advantageously in the range from 150 to 500 mm.
  • the lower section has a threaded box on one end face and a threaded pin on the other end face. It is hereby possible to connect the lower section directly to the upper section made of metal without an intermediate nipple and also to screw the remainder of the previously used lower section onto the underside of the new lower section.
  • the lower section has a central bore of 20 to 50 mm in diameter, which is similar to hollow electrodes but better, but not continuous, through.
  • the lateral surface of the lower section can also advantageously be unprocessed.
  • the electrodes can have a smaller dimension than conventional electrodes.
  • the electrodes have considerable shock resistance and greater resistance to side erosion.
  • the carbon electrode parts can be pressed, annealed, impregnated and graphitized more easily than is the case with larger dimensioned electrodes.
  • the electrode according to the invention can advantageously be used for the production of non-ferrous metals, such as copper and cobalt, but also for the production of corundum, silicon, etc.
  • the electrode is preferred for the production of electrical steel.
  • the electrode according to the invention is particularly suitable for the production of electrical steel in the so-called “high power” or “ultra high power” range at current intensities of 40 to 80 KA, the diameter of the lower section then being in the range of approximately 400 to 600 mm Find.
  • a particularly preferred current load for the electrodes according to the invention is in the range from 50 to 75 KA for the aforementioned diameters of the carbon part.
  • An embodiment of an electrode according to the invention is shown in longitudinal section in the figure, but the invention is not limited to this.
  • the cooling medium usually water
  • the cooling medium also enters a chamber within the screw nipple 1, the z. B. is made of cast iron.
  • the upper section 5 made of metal here consists of an upper area of larger diameter and a lower-lying area of smaller diameter, which is drawn into the screw nipple 1, which is the connection to the lower section 6 made of carbon material, which is made of fine-grained, high-strength, highly graphitic carbon material with a bulk density of at least 1.70 g / cm 3 is formed.
  • the high-temperature-resistant coating 4 is formed from a number of individual molded parts, which can be carried on a bearing 7.
  • the high-temperature-resistant insulation 4 is adjoined here by an electrically conductive intermediate layer 11, which is delimited inwards by the inner metal shaft or its section of smaller diameter 12 which is drawn inwards.
  • bores can also be provided through which inserted pins ensure a good fit of the high-temperature-resistant molded parts via a spring.
  • Current can be supplied to the electrode via the jaws 18.
  • the object of the invention is not limited to the construction shown in the figure. So z. B. particularly advantageous in the context of the invention constructions that have deviations from the electrode type shown in the figure.
  • the metal shaft has an essentially constant diameter. Rings made of high temperature resistant material - preferably graphite - can be screwed onto these.
  • the cooling system can preferably be designed in such a way that the cooling medium flows around the nipple in its upper outer region, but this does not enter the nipple itself.
  • An electrically conductive intermediate layer is not always provided in such constructions.
  • the carbon material of the edible lower section is formed from fine-grained, high-strength, highly graphitic carbon material with a bulk density of at least 1.7 g / cm 3 .
  • An electrode was used, the upper section of which was made of copper and which was cooled with water via a system of flow and return channels.
  • the copper shaft which was inside the furnace atmosphere, was protected by a high temperature resistant coating.
  • the lower section was screwed to the metal shaft via a graphite nipple.
  • the lower section had a smaller diameter than the upper section, which was approximately 350 mm.
  • the specific electrical resistance was 5.1 ⁇ mm 2 / m.
  • the electrode had a central bore of 30 mm in diameter.
  • Three electrodes were inserted into an oven with a capacity of 50 t, in which piece of scrap was used as the input material.
  • the furnace was operated with three phases with a maximum phase current of 50 KA at a voltage of 490 V.
  • the flectrode according to the invention could be used in continuous operation, with a graphite consumption of 3.1 kg / t liquid steel.

Landscapes

  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Physics & Mathematics (AREA)
  • Discharge Heating (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Furnace Details (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
  • Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
  • Fats And Perfumes (AREA)
  • Resistance Heating (AREA)
  • Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Conductive Materials (AREA)
  • Ceramic Products (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
EP82102771A 1981-04-23 1982-04-01 Elektrode für Lichtbogenöfen und deren Verwendung Expired EP0063711B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82102771T ATE15120T1 (de) 1981-04-23 1982-04-01 Elektrode fuer lichtbogenoefen und deren verwendung.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19813116221 DE3116221A1 (de) 1981-04-23 1981-04-23 Elektrode fuer lichtbogenoefen und deren verwendung
DE3116221 1981-04-23

Publications (2)

Publication Number Publication Date
EP0063711A1 EP0063711A1 (de) 1982-11-03
EP0063711B1 true EP0063711B1 (de) 1985-08-21

Family

ID=6130709

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82102771A Expired EP0063711B1 (de) 1981-04-23 1982-04-01 Elektrode für Lichtbogenöfen und deren Verwendung

Country Status (18)

Country Link
EP (1) EP0063711B1 (no)
JP (1) JPS5894794A (no)
AT (1) ATE15120T1 (no)
AU (1) AU8219982A (no)
BR (1) BR8202309A (no)
DD (1) DD202362A5 (no)
DE (2) DE3116221A1 (no)
DK (1) DK181782A (no)
ES (1) ES511792A0 (no)
FI (1) FI821029L (no)
GB (1) GB2097638A (no)
GR (1) GR75550B (no)
HU (1) HU186006B (no)
NO (1) NO820908L (no)
PL (1) PL236124A1 (no)
PT (1) PT74764B (no)
TR (1) TR21231A (no)
ZA (1) ZA822054B (no)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH655128A5 (de) * 1983-01-28 1986-03-27 Von Roll Ag Stromleitende elektrode fuer metallurgische oefen.
DE3316366C2 (de) * 1983-05-05 1985-10-17 Mannesmann AG, 4000 Düsseldorf Ofengefäß für einen Gleichstrom-Lichtbogenofen
IT1288858B1 (it) * 1996-02-29 1998-09-25 Danieli Off Mecc Dispositivo adattatore per elettrodi, con funzione di reattanza ausiliaria, in un forno elettrico ad arco.

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE268660C (no) *
SE337435B (no) * 1965-07-13 1971-08-09 J Oestberg
FR2176546A1 (en) * 1972-03-23 1973-11-02 Siderurgie Fse Inst Rech Composite furnace electrode - esp for steel prodn
CA1074381A (en) * 1978-05-09 1980-03-25 Otto E. Prenn Composite electrode with non-consumable upper section
DE2725537A1 (de) * 1977-06-06 1978-12-14 Korf Stahl Elektrode fuer lichtbogenoefen
DE2845367C2 (de) * 1978-10-18 1981-01-22 Korf & Fuchs Syst Tech FlUssigkeitsgekühlte Halterung für die Spitze einer Elektrode eines Lichtbogenschmelzofens
US4287381A (en) * 1978-12-19 1981-09-01 British Steel Corporation Electric arc furnace electrodes

Also Published As

Publication number Publication date
ES8400644A1 (es) 1983-11-01
FI821029A7 (fi) 1982-10-24
GB2097638A (en) 1982-11-03
NO820908L (no) 1982-10-25
PT74764A (de) 1982-05-01
ES511792A0 (es) 1983-11-01
ATE15120T1 (de) 1985-09-15
DE3265539D1 (en) 1985-09-26
EP0063711A1 (de) 1982-11-03
DE3116221A1 (de) 1982-11-11
DD202362A5 (de) 1983-09-07
PL236124A1 (no) 1982-12-06
BR8202309A (pt) 1983-04-05
HU186006B (en) 1985-05-28
FI821029L (fi) 1982-10-24
PT74764B (de) 1983-11-15
FI821029A0 (fi) 1982-03-24
DK181782A (da) 1982-10-24
TR21231A (tr) 1984-02-06
AU8219982A (en) 1982-11-25
ZA822054B (en) 1983-03-30
JPS5894794A (ja) 1983-06-06
GR75550B (no) 1984-07-27

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