EP0344413B1 - Four pour le traitement thermique de pièces en fer et en acier - Google Patents

Four pour le traitement thermique de pièces en fer et en acier Download PDF

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Publication number
EP0344413B1
EP0344413B1 EP89104384A EP89104384A EP0344413B1 EP 0344413 B1 EP0344413 B1 EP 0344413B1 EP 89104384 A EP89104384 A EP 89104384A EP 89104384 A EP89104384 A EP 89104384A EP 0344413 B1 EP0344413 B1 EP 0344413B1
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EP
European Patent Office
Prior art keywords
heating
heating elements
furnace
heating chamber
batch
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.)
Revoked
Application number
EP89104384A
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German (de)
English (en)
Other versions
EP0344413A1 (fr
Inventor
Albert Fleiter
Wolfgang Dipl.-Ing. Peter
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.)
Ipsen International GmbH
Original Assignee
Ipsen International GmbH
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
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First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=6355503&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0344413(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Ipsen International GmbH filed Critical Ipsen International GmbH
Publication of EP0344413A1 publication Critical patent/EP0344413A1/fr
Application granted granted Critical
Publication of EP0344413B1 publication Critical patent/EP0344413B1/fr
Anticipated expiration legal-status Critical
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D7/00—Forming, maintaining, or circulating atmospheres in heating chambers
    • F27D7/04—Circulating atmospheres by mechanical means
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/767—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material with forced gas circulation; Reheating thereof
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/773—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material under reduced pressure or vacuum
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D11/00—Arrangement of elements for electric heating in or on furnaces
    • F27D11/02—Ohmic resistance heating

Definitions

  • the invention relates to a furnace for the heat treatment of batches of iron and steel parts with a furnace housing and a heating chamber arranged therein as well as electrically operated heating elements arranged in the heating chamber for heating the batch, the heating elements arranged vertically in the heating chamber being tubular and made of gas can be flowed through from top to bottom while heating.
  • Furnaces for the heat treatment of iron and steel parts which have heating elements arranged inside the heating chamber for heating the batch, which heating elements consist either of graphite or, for higher thermal stress, of molybdenum. These heating elements are usually attached to the inner wall of the heating chamber, the electrical connections of the heating elements being passed through the wall of the heating chamber.
  • the furnaces designed in this way are mainly operated as vacuum furnaces.
  • the furnace is evacuated for the duration of the batch heating.
  • the batch is therefore heated almost exclusively by the heat radiated by the heating elements.
  • the known furnace has a system for cooling gas flow, in which the batch can be flowed through in a targeted manner via several cooling gas openings in the heating chamber.
  • targeted cooling of certain areas of the batch can be carried out by only partially charging cooling gas openings.
  • the known furnace is charged in the vertical direction by moving the bottom loaded with the batch to the bottom of the furnace, the batch entering the heating chamber.
  • This known construction has the disadvantage of only a low heating rate in the lower temperature range, in which the heat transfer by radiation is still low. Convection can bring significant improvements in this temperature range, but the air circulating inside the heating chamber takes a long time to warm up on the heating elements and to transfer this heat convectively to the batch.
  • the small surface area of the heating elements made of solid material their radiation area is small.
  • the size of the radiation surface is proportional to the size of the amount of heat exchanged by radiation.
  • the heating elements continue to radiate heat even after the energy supply has ended, which delays the start of the subsequent cooling phase.
  • the invention has for its object to provide a furnace for the heat treatment of iron and steel parts, which allows rapid and uniform heating in any temperature range, which works with good efficiency and which allows a rapid temperature reduction in the cooling phase.
  • the heating elements are designed to be open towards the bottom.
  • An oven designed in this way has the advantage that rapid heating of the batch can be achieved both in the area of low temperature ( ⁇ 600 ° C) and in the area of pure radiant heat (> 600 ° C).
  • the gas under atmospheric or excess pressure is forced through the heating elements into the heating chamber in the lower temperature range, which results in very good convective heat transfer between the heating element and gas and thus a high outlet temperature of the gas.
  • the furnace is operated in the higher temperature range, the large specific surface area of the heating elements enables a strong emission of heat radiation.
  • the low wall thickness of the heating elements helps to lower the temperature at the start of the cooling phase. The invention therefore makes it possible to operate the furnace with greater efficiency both in the heating-up and in the cooling-down phase.
  • the heating element is arranged vertically in the heating chamber and flows through from top to bottom, the heating elements being open at least downwards.
  • the structural design of the furnace is particularly simple, the heating gas emerging from the heating elements reaching the lower region of the batch and leading there to a desired, preferred heating.
  • the heating elements may be advantageous to provide the heating elements with radial openings in order to also act on the charge in a targeted manner in the convective heating phase.
  • the heating elements are fastened at their upper end in the heating chamber, as a result of which they have only a small contact area with elements of the heating chamber, so that the heat generated by them is completely available for heating the heating gas or the batch.
  • a cylindrical heating chamber 2 constructed of heat-resistant materials is arranged in a container-shaped, primarily cylindrical furnace housing 1.
  • the heating chamber 2 like the furnace housing 1, is constructed in two parts, the lower part being formed by a heating chamber base 3 and a base 4 of the furnace housing 1.
  • a plurality of stove supports 5 are fastened, which, projecting through the heating chamber bottom 3, form a grate for receiving the batch 6 to be subjected to heat treatment.
  • the batch 6 stands on the hearth supports 5 within the heating chamber 2.
  • a plurality of axially extending, tubular heating elements 7 are arranged in the vicinity of the inner lateral surface of the heating chamber 2.
  • the heating elements 7 are cylindrical graphite tubes which are open both at the top and at the bottom. Depending on the area of application, heating elements made of molybdenum can also be used.
  • the heating elements 7 are attached at their upper end with the interposition of ceramic sleeves 8 on a cover 9 of the heating chamber 2.
  • the heating elements 7 can both be firmly seated in the ceramic sleeves 8 and can also be suspended in the ceramic sleeves by means of suitable collars, their vertical alignment then being effected by gravity.
  • a fan chamber 10 in which a wing of a fan 11 is arranged centrally, which is driven by a fan motor 12 fastened thereon.
  • a fan motor 12 Fastened thereon.
  • gas is sucked from the inside of the heating chamber 2 to the front side of the fan 11 and is conveyed radially outwards into the fan chamber 10, from where the gas flows through the ceramic sleeves 8 into the tubular heating elements 7 arrives.
  • the fan 11 is made of heat-resistant material and is shielded from the fan motor 12 by a suitable, heat-shielding wall 14.
  • a shield 15 is formed by the annular suction channel 13 of the cover 9.
  • the heating elements 7 are provided at their lower and upper ends with electrical connections 16, 17, via which an electrical current for heating the heating elements 7 is supplied.
  • the electrical connections 16, 17 are largely thermally decoupled from the components of the heating chamber 2 and the furnace housing 1, so that no undesired heat flows can occur here.
  • the heating elements 7 are open at the bottom and, as shown in the drawing, have additional lateral openings 18 aligned in the direction of the charge 6, the size, the position and the number of openings 18 being able to vary depending on the application. In any case, it is advantageous to bring the hot gas emerging from the heating elements 7 into the lower area of the batch, where experience has shown that the mass to be heated is greatest, which among other things. is caused by heat loss via the stove supports 5.
  • cooling gas openings 19 In the lateral surface and in the heating chamber base 3 there are a large number of cooling gas openings 19, through which cooling gas conveyed by a blower (not shown) reaches the interior of the heating chamber 2.
  • the cooling gas openings 19 in the form of nozzles are preferably oriented such that they blow on the batch 6 directly.
  • the cooling gas openings 19 can be combined in groups.
  • the drawing shows how a lower ring distributor 20 and an upper ring distributor 21 can be used to separately apply the cooling gas openings 19 located further down or higher.
  • the cooling gas is supplied to the lower ring distributor 20 and upper ring distributor 21 via respective connecting pieces 23, 24. Further cooling gas openings 19 are located at the bottom of the heating chamber 2.
  • the cooling gas supplied via a floor distributor 22 flows from them.
  • the oven described thus works with three cooling zones which can be acted upon independently of one another.
  • the heated cooling gas emerging from the interior of the cooling chamber 2 passes via the intake duct 13, the fan chamber 10 and in this case opened hatch openings 25 into the interior of the furnace housing 1 and from there via a suction nozzle 26 back to a heat exchanger.
  • the hatch openings 25 are located on the top of the fan chamber 10 and are only opened during the cooling phase, but remain closed during the heating phase of the furnace.
  • the oven works in the following way: When the bottom 4 is drained, the batch 6 is placed on the stove supports 5 and the bottom 4 is moved vertically from below against the furnace housing 1, as a result of which the batch 6 enters the interior of the heating chamber 2.
  • the bottom 4 is attached to the furnace housing 1 in a vacuum-tight manner by means of corresponding fastening elements.
  • the furnace is then evacuated and a protective gas, such as nitrogen or argon, is introduced.
  • the fan 11 is actuated via the fan motor 12 and the heating elements 7 are heated via the electrical connections 16, 17.
  • the pressure in the furnace housing 1 is between 500 and 2000 mbar.
  • the protective gas conveyed by the fan 11 passes through the fan chamber 10 into the heating elements 7, flows through them with convective heating and reaches the lower region of the heating chamber 2.
  • the hot gas rising within the heating chamber 2 flows through the batch, heats it up convectively and passes over the intake duct 13 back to the fan 11.
  • This convective heating phase is ended at a batch temperature of about 600 o C.
  • the fan 11 is stopped and the further heat transfer takes place almost exclusively via the radiant heat of the heating elements 7 transferred to the charge 6.
  • the interior of the furnace housing 1 is again evacuated so that the radiant heat of the heating elements 7 is not used for further heating of the protective gas must be used.
  • the heat transfer takes place exclusively by radiation, the size of this radiation being very dependent on the temperature of the heating elements 7, in addition to the size of the radiating surface.
  • the heat exchange during the heating phase taking place in a vacuum takes place with the same heating elements as the primarily convective heat transfer at the beginning of the heating.
  • the convective heat transfer in the low temperature range significantly accelerates the batch heating at the start of the heating phase.
  • the heating elements 7 are switched off.
  • the cooling circuit is then started, so that the cooling gas distributed via the ring distributors 20, 21 and the bottom distributor 22 flows into the interior of the heating chamber 2 via the cooling gas openings 19 and the batch 6 cools down.
  • this cooling can take place in a directed manner in order to achieve a specific material structure in the batch. Since the heating elements 7 are located in the region of the mouth of the cooling gas openings 19 let into the jacket of the heating chamber 2, the heating elements 7 are already strongly cooled immediately after the beginning of the cooling process, so that they can no longer emit any significant heat radiation.
  • the furnace housing 1 and base 4 are separated again, so that the base 4 can be lowered vertically to remove the batch 6.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Furnace Details (AREA)

Claims (7)

  1. Four pour le traitement thermique de charges composées de pièces en fer et en acier, comportant une enveloppe de four et une chambre de chauffe disposée à l'intérieur ainsi que des éléments chauffants disposés dans la chambre de chauffe et commandés électriquement pour le chauffage de la charge, les éléments chauffants, disposés verticalement dans la chambre de chauffe étant réalisés de forme tubulaire et pouvant être parcourus par du gaz s'écoulant du haut vers le bas en étant chauffé, caractérisé en ce que le éléments chauffants sont constitués en étant ouverts vers le bas.
  2. Four selon la revendication 1, caractérisé en ce que les éléments chauffants (7) sont munis d'ouvertures radiales (18).
  3. Four selon la revendication 1, caractérisé en ce que les éléments chauffants (7) sont fixés par leur extrémité supérieure dans la chambre de chauffe (2).
  4. Four selon la revendication 3, caractérisé en ce que les éléments chauffants (7) sont fixés avec intercalation de manchons en céramique (8).
  5. Four selon la revendication 1, caractérisé par un ventilateur (11) pour la circulation du gaz.
  6. Four selon la revendication 5, caractérisé par un canal d'aspiration annulaire (13) débouchant à la partie supérieure de la chambre de chauffe (2), ce canal menant d'autre part au ventilateur (11) et étant limité par un écran (15) disposé entre la chambre de chauffe (2) et le ventilateur (11).
  7. Four selon la revendication 1, caractérisé en ce que les éléments chauffants (7) se trouvent dans la zone de l'embouchure d'orifices de gaz de refroidissement (19) encastrés dans l'enveloppe de la chambre de chauffe (2).
EP89104384A 1988-05-31 1989-03-13 Four pour le traitement thermique de pièces en fer et en acier Revoked EP0344413B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3818471 1988-05-31
DE3818471A DE3818471A1 (de) 1988-05-31 1988-05-31 Ofen zur waermebehandlung von eisen- und stahlteilen

Publications (2)

Publication Number Publication Date
EP0344413A1 EP0344413A1 (fr) 1989-12-06
EP0344413B1 true EP0344413B1 (fr) 1993-05-12

Family

ID=6355503

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89104384A Revoked EP0344413B1 (fr) 1988-05-31 1989-03-13 Four pour le traitement thermique de pièces en fer et en acier

Country Status (3)

Country Link
US (1) US4970372A (fr)
EP (1) EP0344413B1 (fr)
DE (2) DE3818471A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023150814A1 (fr) 2022-02-09 2023-08-17 Ebner Industrieofenbau Gmbh Dispositif de chauffage

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2579561B2 (ja) * 1991-03-22 1997-02-05 東海カーボン株式会社 ＳｉＣウイスカーの製造装置
US5267257A (en) * 1991-08-14 1993-11-30 Grier-Jhawar-Mercer, Inc. Vacuum furnace with convection heating and cooling
DE4400326C2 (de) * 1994-01-07 2002-10-31 Ald Vacuum Techn Ag Vorrichtung zum Härten metallischer Werkstücke
US6080964A (en) * 1998-04-16 2000-06-27 Micafil Vakuumtechnik Ag Process for predrying a coil block containing at least one winding and solid insulation
DE10022788B4 (de) * 2000-05-10 2005-11-24 Kramer, Carl, Prof. Dr.-Ing. Heißgasventilator zum Einbau in einen Kammerofen
KR100988570B1 (ko) * 2003-04-10 2010-10-19 삼성전자주식회사 가열조리기
US7598477B2 (en) * 2005-02-07 2009-10-06 Guy Smith Vacuum muffle quench furnace
US7531769B2 (en) * 2006-06-13 2009-05-12 Guy Smith Carbon fiber composite muffle
EP2218998B1 (fr) * 2009-02-03 2012-12-19 Ipsen, Inc. Mécanisme d'étanchéité pour four de traitement à la chaleur sous vide

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0313889A1 (fr) * 1987-10-28 1989-05-03 Degussa Aktiengesellschaft Four sous vide pour le traitement à chaud de pièces métalliques

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE275586C (fr) * 1900-01-01
US845051A (en) * 1906-12-06 1907-02-26 Rolf Von Brockdorff Electric-resistance apparatus.
US1809227A (en) * 1926-03-11 1931-06-09 Thaddeus F Baily Metallic resistor element
FR2315541A1 (fr) * 1975-06-24 1977-01-21 Vide & Traitement Sa Four pour traitements thermiques ou thermochimiques a deux systemes de chauffage
DE2732133C2 (de) * 1977-07-15 1982-09-02 Linde Ag, 6200 Wiesbaden Elektroerhitzer
DE2839807C2 (de) * 1978-09-13 1986-04-17 Degussa Ag, 6000 Frankfurt Vakuumofen mit Gaskühleinrichtung
DE3735186C1 (de) * 1987-10-17 1988-09-15 Ulrich Wingens Vakuum-Kammerofen

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0313889A1 (fr) * 1987-10-28 1989-05-03 Degussa Aktiengesellschaft Four sous vide pour le traitement à chaud de pièces métalliques

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023150814A1 (fr) 2022-02-09 2023-08-17 Ebner Industrieofenbau Gmbh Dispositif de chauffage

Also Published As

Publication number Publication date
DE3818471A1 (de) 1989-12-21
US4970372A (en) 1990-11-13
EP0344413A1 (fr) 1989-12-06
DE58904311D1 (de) 1993-06-17

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