EP0897017B1 - Tower furnace for heat treatment of metal strips - Google Patents

Tower furnace for heat treatment of metal strips Download PDF

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Publication number
EP0897017B1
EP0897017B1 EP98890147A EP98890147A EP0897017B1 EP 0897017 B1 EP0897017 B1 EP 0897017B1 EP 98890147 A EP98890147 A EP 98890147A EP 98890147 A EP98890147 A EP 98890147A EP 0897017 B1 EP0897017 B1 EP 0897017B1
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EP
European Patent Office
Prior art keywords
muffle
furnace
heat treatment
metal strips
plug
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 - Lifetime
Application number
EP98890147A
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German (de)
French (fr)
Other versions
EP0897017A1 (en
Inventor
Peter Helmut Dipl.-Ing. Ebner
Heribert Dipl.-Ing. Lochner
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Individual
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Individual
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Publication date
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Publication of EP0897017A1 publication Critical patent/EP0897017A1/en
Application granted granted Critical
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0043—Muffle furnaces; Retort furnaces
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/66—Tower-type furnaces

Definitions

  • the invention relates to a tower furnace for the heat treatment of metal strips with the belt running through the entire furnace height Muffle.
  • Metal strips in particular made of Cr-Ni steel or Cr steel, have hitherto been continuously bright annealed in so-called door furnaces, the heat treatment taking place under a protective gas consisting of H 2 or H 2 / N 2 mixture.
  • the strip is heated by radiation in a muffle heated on the outside and subsequently cooled in a cooling system. Both gas burners and electrical resistance heating elements can be used to heat the muffle.
  • the furnace temperature is due to the material used Limited muffle.
  • the strip heating is therefore from the muffle counter temperature dependent and runs according to one of the emission factors of the band and the muffle certain function.
  • the muffle length results from the tear length of the used Material, d. H. that the weight of the muffle leads to their destruction can.
  • the furnace In order to bring the strip temperature close to the maximum muffle temperature, it is known to make the furnace divided.
  • the strip is preheated in a lower, usually gas-heated, furnace provided with a glow muffle and then passes through a muffle-free, electrically heated furnace arranged above it, which can be operated at higher temperatures. Since part of the oven is designed to be muffle, there is an extended rinsing time. H 2 operation results in higher energy losses on the outer wall of the oven. Compared to air or smoke gases, the heat transfer in the insulating bodies, for. B. masonry or ceramic wool, significantly increased by H 2 . Since two stoves arranged one above the other are provided, there is a reduction in the heating performance of the entire stove at the flange points of the two stoves, apart from the increased construction costs.
  • the invention has for its object a tower furnace of the aforementioned To create the way in which the desired strip end temperature is reached without the Exceeding the tear length of the muffle and without the band heating due to colder Oven parts delayed.
  • the invention solves this problem in that an insulated plug with electrical Heating is inserted into the top of the muffle, whereas one is preferably under the plug gas-heated preheating room.
  • the furnace can be brightly glowed even after a long interruption in production with a normal addition of H 2 .
  • the energy losses are negligible due to the slightly reduced temperature of the muffle outer wall in the plug area.
  • this lowering of the temperature there is at the same time an increase in the strength of the material, which in turn allows the muffle to be lengthened, with no risk that the tear length of the muffle will be exceeded.
  • the drawing shows an exemplary embodiment of a tower furnace schematically in longitudinal section.

Abstract

The tower furnace for heat treatment of metal strips (6) incorporates a muffle (3) which extends over the entire furnace height. An isolated plug (1) with an electric heating element (2) is inserted into the top section of the muffle, while below the plug there is a preferably gas heated preliminary heating space (4) for the strip.

Description

Die Erfindung bezieht sich auf einen Turmofen zur Wärmebehandlung von Metallbändem mit sich über die ganze Ofenhöhe erstreckender, vom Band durchlaufener Muffel.The invention relates to a tower furnace for the heat treatment of metal strips with the belt running through the entire furnace height Muffle.

Metallbänder, insbesondere aus Cr-Ni-Stahl bzw. Cr-Stahl, werden bisher in sogenannten Turmöfen kontinuierlich blankgeglüht, wobei die Wärmebehandlung unter Schutzgas, bestehend aus H2 bzw. H2/N2-Gemisch erfolgt. Das Band wird in einer auf der Außenseite beheizten Glühmuffel durch Strahlung erwärmt und nachfolgend in einem Kühlsystem abgekühlt Zur Beheizung der Muffel können sowohl Gasbrenner als auch elektrische Widerstandsheizelemente herangezogen werden.Metal strips, in particular made of Cr-Ni steel or Cr steel, have hitherto been continuously bright annealed in so-called door furnaces, the heat treatment taking place under a protective gas consisting of H 2 or H 2 / N 2 mixture. The strip is heated by radiation in a muffle heated on the outside and subsequently cooled in a cooling system. Both gas burners and electrical resistance heating elements can be used to heat the muffle.

Es ist auch eine Erwärmung des Bandes in einem elektrisch beheizten Ofen ohne Muffel bekannt. Dabei besteht aber der Nachteil, daß sich bis zum Erreichen einer einwandfrei blankgeglühten Bandoberfläche bei Produktionsunterbrechungen eine lange Spülzeit mit hohem Wasserstoffverbrauch während des Spül- und Produktionsbetriebes ergibt.There is also heating of the belt in an electrically heated oven without Muffle known. However, there is the disadvantage that until a perfectly bright annealed strip surface during production interruptions a long Flushing time with high hydrogen consumption during flushing and production operations results.

Um einen möglichst hohen Materialdurchsatz zu erreichen, wird mit maximal möglicher Ofentemperatur geglüht Die Ofentemperatur ist jedoch durch den Werkstoff der eingesetzten Muffel begrenzt. Die Banderwärmung ist also von der Muffelgegentemperatur abhängig und verläuft nach einer von den Emissionsfaktoren des Bandes und der Muffel bestimmten Funktion. Die Muffellänge ergibt sich aus der Reißlänge des verwendeten Werkstoffes, d. h. daß das Eigengewicht der Muffel zu deren Zerstörung führen kann.In order to achieve the highest possible material throughput, the maximum possible Furnace temperature annealed However, the furnace temperature is due to the material used Limited muffle. The strip heating is therefore from the muffle counter temperature dependent and runs according to one of the emission factors of the band and the muffle certain function. The muffle length results from the tear length of the used Material, d. H. that the weight of the muffle leads to their destruction can.

Um die Bandtemperatur in die Nähe der Muffel-Maximaltemperatur zu bringen, ist es bekannt, den Ofen geteilt auszuführen. Dabei wird in einem unteren, mit einer Glühmuffel versehenen meist gasbeheizten Ofen das Band vorgewärmt und durchläuft dann einen darüber angeordneten muffellosen elektrisch beheizten Ofen, der mit höheren Temperaturen gefahren werden kann. Da ein Teil des Ofens muffellos ausgeführt ist, ergibt sich wieder eine verlängerte Spülzeit Durch den H2-Betrieb sind höhere Energieverluste der Außenwand des Ofens gegeben. Gegenüber Luft- oder Rauchgasen wird der Wärmedurchgang in den Isolierkörpern, z. B. Mauerung oder keramische Wolle, durch H2 deutlich erhöht. Da zwei übereinander angeordnete Öfen vorgesehen sind, ergibt sich an den Flanschstellen der beiden Öfen eine Verminderung der Erwärmungsleistung des Gesamtofens, abgesehen von den erhöhten Baukosten.In order to bring the strip temperature close to the maximum muffle temperature, it is known to make the furnace divided. The strip is preheated in a lower, usually gas-heated, furnace provided with a glow muffle and then passes through a muffle-free, electrically heated furnace arranged above it, which can be operated at higher temperatures. Since part of the oven is designed to be muffle, there is an extended rinsing time. H 2 operation results in higher energy losses on the outer wall of the oven. Compared to air or smoke gases, the heat transfer in the insulating bodies, for. B. masonry or ceramic wool, significantly increased by H 2 . Since two stoves arranged one above the other are provided, there is a reduction in the heating performance of the entire stove at the flange points of the two stoves, apart from the increased construction costs.

Der Erfindung liegt die Aufgabe zugrunde, einen Turmofen der eingangs geschilderten Art zu schaffen, bei dem die gewünschte Bandendtemperatur erreicht wird, ohne die Reißlänge der Muffel zu überschreiten und ohne die Banderwärmung durch kältere Ofenteile zu verzögem.The invention has for its object a tower furnace of the aforementioned To create the way in which the desired strip end temperature is reached without the Exceeding the tear length of the muffle and without the band heating due to colder Oven parts delayed.

Die Erfindung löst diese Aufgabe dadurch, daß ein isolierter Stopfen mit elektrischer Heizung oben in die Muffel eingesetzt ist, wogegen sich unter dem Stopfen ein vorzugsweise gasbeheizter Vorwärmraum befindet.The invention solves this problem in that an insulated plug with electrical Heating is inserted into the top of the muffle, whereas one is preferably under the plug gas-heated preheating room.

Da der isolierte Stopfen in seinem Volumen wesentlich kleiner als ein muffelloser Ofen ist, ergibt sich auch nach längerer Produktionsunterbrechung bereits kurzfristig bei normaler Zugabemenge von H2 die Blankglühfähigkeit des Ofens. Die Energieverluste sind auf Grund der im Stopfenbereich geringfügig abgesenkten Temperatur der Muffelaußenwand vernachlässigbar. Durch diese Temperaturabsenkung ist aber gleichzeitig eine Festigkeitserhöhung des Materials gegeben, die wiederum eine Verlängerung der Muffel erlaubt, wobei keine Gefahr besteht, daß die Reißlänge der Muffel überschritten wird. Since the volume of the insulated stopper is significantly smaller than that of a muffle-free furnace, the furnace can be brightly glowed even after a long interruption in production with a normal addition of H 2 . The energy losses are negligible due to the slightly reduced temperature of the muffle outer wall in the plug area. As a result of this lowering of the temperature, there is at the same time an increase in the strength of the material, which in turn allows the muffle to be lengthened, with no risk that the tear length of the muffle will be exceeded.

Die Zeichnung zeigt als Ausführungsbeispiel einen Turmofen schematisch im Längsschnitt.The drawing shows an exemplary embodiment of a tower furnace schematically in longitudinal section.

We ersichtlich, ist ein isolierter Stopfen 1 mit elektrischer Heizung 2 oben in die sich über die ganze Ofenhöhe erstreckende Muffel 3 eingesetzt. Unter den Stopfen 1 befindet sich ein Vorwärmraum 4, wobei dort die Muffel von außen durch den Freiraum 4a gasbeheizt ist Mit 5 ist die Außenisolation bezeichnet We ersichtlich, durchläuft das zur Wärmebehandlung vorgesehene Band 6 die ganze Ofenlänge.We can see an insulated plug 1 with an electric heater 2 in the top Muffle 3 extending over the entire furnace height is used. Located under the stopper 1 a preheating room 4, where the muffle from the outside through the free space 4a is heated by gas. 5 indicates the external insulation. We see that it goes through Belt 6 provided for heat treatment the entire length of the furnace.

Claims (1)

  1. A tower furnace for heat treatment of metal strips, comprising a muffle (3) which extends up the entire height of the furnace and through which the strip (6) runs, characterised in that an insulated plug (1) with electric heating (2) is inserted into the top of the muffle (3) and a preferably gasheated preheating chamber (4) is situated under the plug (1).
EP98890147A 1997-06-10 1998-05-20 Tower furnace for heat treatment of metal strips Expired - Lifetime EP0897017B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AT0099997A AT405055B (en) 1997-06-10 1997-06-10 TOWER STOVES FOR THE HEAT TREATMENT OF METAL STRIPS
AT99997 1997-06-10
AT999/97 1997-06-10

Publications (2)

Publication Number Publication Date
EP0897017A1 EP0897017A1 (en) 1999-02-17
EP0897017B1 true EP0897017B1 (en) 2001-10-31

Family

ID=3504621

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98890147A Expired - Lifetime EP0897017B1 (en) 1997-06-10 1998-05-20 Tower furnace for heat treatment of metal strips

Country Status (8)

Country Link
US (1) US6031206A (en)
EP (1) EP0897017B1 (en)
JP (1) JP4077930B2 (en)
KR (1) KR19990006771A (en)
AT (2) AT405055B (en)
DE (1) DE59801932D1 (en)
ES (1) ES2167060T3 (en)
TW (1) TW410239B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT408452B (en) * 2000-06-29 2001-12-27 Ebner Peter Dipl Ing TOWER STOVES FOR THE HEAT TREATMENT OF METAL STRIPS
AT507670B1 (en) * 2009-07-03 2010-07-15 Ebner Ind Ofenbau TOWER FOR THE HEAT TREATMENT OF A METAL STRIP
JP5550924B2 (en) * 2010-01-26 2014-07-16 光洋サーモシステム株式会社 Continuously heated muffle furnace

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE652552C (en) * 1937-11-02 Siemens Schuckertwerke Akt Ges Tower furnace with a gas-tight inner jacket surrounding the drawn-through material
US2104886A (en) * 1934-04-30 1938-01-11 Firm Heraeus Vacuumschmelze Ag Electrically heated annealing furnace
FR836893A (en) * 1937-04-20 1939-01-27 Roechlingsche Eisen & Stahl White annealing furnace
US3823003A (en) * 1970-04-14 1974-07-09 Dow Chemical Co Preparation of metals
US4299565A (en) * 1977-07-25 1981-11-10 Kawasaki Steel Corporation Heating furnace
US4229163A (en) * 1977-07-25 1980-10-21 Kawasaki Steel Corporation Heating furnace
JPS5811493B2 (en) * 1978-12-29 1983-03-03 新日本製鐵株式会社 Continuous annealing equipment for cold rolled steel strip
EP0181830B1 (en) * 1984-11-08 1991-06-12 Mitsubishi Jukogyo Kabushiki Kaisha Method and apparatus for heating a strip of metallic material in a continuous annealing furnace
JPS61157641A (en) * 1984-12-28 1986-07-17 Chugai Ro Kogyo Kaisha Ltd Continuous annealing furnace for metallic strip
WO1987000555A1 (en) * 1985-07-18 1987-01-29 Nippon Kokan Kabushiki Kaisha Continuous strip steel processing line having direct firing furnace
US5609785A (en) * 1992-10-05 1997-03-11 Acon Finland Oy Ltd. Method and apparatus for improving the performance of a heating furnace for metal slabs
JP2815086B2 (en) * 1994-02-21 1998-10-27 住友金属工業株式会社 Vertical continuous annealing furnace for steel strip
JP3356864B2 (en) * 1994-03-31 2002-12-16 中外炉工業株式会社 Heating zone of vertical continuous bright annealing furnace for steel strip
JPH08260059A (en) * 1995-03-17 1996-10-08 Nippon Steel Corp Continuous annealing furnace excellent in atmosphere control ability
NL1002856C2 (en) * 1996-04-12 1997-10-15 Thermtec B V Vertical annealing furnace for a belt treatment installation.

Also Published As

Publication number Publication date
JP4077930B2 (en) 2008-04-23
DE59801932D1 (en) 2001-12-06
ATE207973T1 (en) 2001-11-15
ATA99997A (en) 1998-09-15
US6031206A (en) 2000-02-29
ES2167060T3 (en) 2002-05-01
AT405055B (en) 1999-05-25
EP0897017A1 (en) 1999-02-17
JPH1150156A (en) 1999-02-23
KR19990006771A (en) 1999-01-25
TW410239B (en) 2000-11-01

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