EP0331929A1 - Method for producing a protective atmosphere for heat treating ferrous and non-ferrous metals - Google Patents

Method for producing a protective atmosphere for heat treating ferrous and non-ferrous metals Download PDF

Info

Publication number
EP0331929A1
EP0331929A1 EP89102430A EP89102430A EP0331929A1 EP 0331929 A1 EP0331929 A1 EP 0331929A1 EP 89102430 A EP89102430 A EP 89102430A EP 89102430 A EP89102430 A EP 89102430A EP 0331929 A1 EP0331929 A1 EP 0331929A1
Authority
EP
European Patent Office
Prior art keywords
combustion
gas
protective gas
ferrous
producing
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.)
Granted
Application number
EP89102430A
Other languages
German (de)
French (fr)
Other versions
EP0331929B1 (en
Inventor
Gottfried Dipl.-Ing. Böhm
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.)
Messer Griesheim GmbH
Original Assignee
Messer Griesheim 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
Application filed by Messer Griesheim GmbH filed Critical Messer Griesheim GmbH
Priority to AT89102430T priority Critical patent/ATE78877T1/en
Publication of EP0331929A1 publication Critical patent/EP0331929A1/en
Application granted granted Critical
Publication of EP0331929B1 publication Critical patent/EP0331929B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • C21D1/76—Adjusting the composition of the atmosphere

Definitions

  • the invention relates to a method for producing a protective gas for the heat treatment of iron and non-ferrous metals, in which a hydrocarbon-containing fuel gas is burned with air in a jacket jet tube and reacted with vaporized methanol without a catalyst, according to the preamble of claim 1.
  • Protective gas for the heat treatment of metals is conventionally produced in generators by burning combustion gases containing hydrocarbons. This type of production is very complex. A cheaper alternative is the reaction in jacket pipes, which is carried out with the help of catalysts.
  • Sheathed jet pipes are used in industrial furnace construction to heat heat treatment systems with artificial atmospheres. They can be heated with gas or electrically.
  • a jacket jet pipe consists essentially of three pipes, namely the outer jacket pipe for heating the furnace chamber, the inner or combustion pipe in which the combustion takes place and the gas supply pipe to the combustion chamber in the combustion pipe.
  • a substoichiometric combustion in the jacket jet pipe would result in reducing components in the exhaust gas (protective gas), but would lead to sooting and to the burning of the pipes.
  • Another way of generating protective gas is to spray nitrogen-methanol mixtures into the annealing furnace. At temperatures above 750 ° C, the methanol decomposes according to the equation CH3 OH ⁇ 2H2 + CO.
  • a carburizing agent such as propane or natural gas can also be added to this cracked gas.
  • This type of protective gas production is very inexpensive, but it requires an externally heated annealing furnace with operating temperatures above 750 ° C.
  • the invention has for its object to provide a method which enables the production of protective gas by burning a hydrocarbon-containing fuel gas in a jacket jet tube even in those cases in which a substoichiometric combustion at furnace temperatures below 750 ° C is required and no external heat is supplied.
  • the invention is based on the knowledge that it is possible to feed a nitrogen-methanol mixture in a sufficient quantity into the combustion chamber of a jacket jet pipe operated with a stoichiometric ratio of ⁇ equal to or close to 1, on the one hand to obtain a desired protective gas atmosphere without on the other hand Oven temperature of 750 ° C is required.
  • the jacket jet In the case of stoichiometric combustion, on the other hand, the jacket jet always has temperatures above 750 ° C.
  • the advantages of the method according to the invention lie above all in the annealing of non-ferrous metal, because it offers an inexpensive alternative to protective gas generated by the generator and to hydrogen-nitrogen mixtures.
  • the method according to the invention is also suitable for bright annealing steel, but drying must be carried out afterwards.
  • a jacket jet is shown in a very simplified form, in which natural gas is burned with air to generate protective gas.
  • the natural gas is supplied through a gas supply pipe 1, which is surrounded concentrically by the combustion pipe 2.
  • the combustion air flows through the combustion tube 2 and forms the flame 4 with the natural gas in the combustion chamber 3.
  • the fuel tube 2 is surrounded concentrically on all sides by the jacket tube 5, but leaves the outlet from the fuel tube 2 free.
  • the flue gases therefore flow back outside the combustion tube 2 and leave the jacket jet pipe through the nozzle 6 as a protective gas, which reaches the furnace directly at high temperature.
  • a nitrogen-methanol mixture is sprayed into the combustion chamber 3.
  • the amount of nitrogen-methanol is measured so that the combustion temperature in combustion chamber 3 does not drop below 750 ° C.
  • the methanol could also be pumped into the jacket tube in pure form and sprayed into the combustion chamber 3.
  • the combustion temperature in combustion chamber 3 is approximately 850 ° C.
  • this shielding gas for example, copper can be bright annealed.

Abstract

Protective gas for the heat treatment of metals is frequently produced in generators. This type of production is expensive. It is simpler for producing a protective gas to burn a hydrocarbon- containing fuel gas such as natural gas or propane in a jacketed jet tube. This is not possible, however, if the combustion is to be less than stoichiometric, that is to say a sooty endothermic gas is to be produced with an external heat supply. In order to allow the production of protective gas nevertheless in such cases, the combustion is carried out stoichiometrically and a mixture of nitrogen and methanol is sprayed into the combustion chamber (3). In this case, the combustion temperature should not fall below 750 DEG C. <IMAGE>

Description

Die Erfindung betrifft ein Verfahren zur Herstellung eines Schutzgases für die Wärmebehandlung von Eisen und Nichteisenmetallen, bei dem ein kohlenwasserstoff­haltiges Brenngas in einem Mantelstrahlrohr mit Luft verbrannt und mit verdampften Methanol ohne Katalysator zur Reaktion gebracht wird, nach dem Oberbegriff des Anspruches 1.The invention relates to a method for producing a protective gas for the heat treatment of iron and non-ferrous metals, in which a hydrocarbon-containing fuel gas is burned with air in a jacket jet tube and reacted with vaporized methanol without a catalyst, according to the preamble of claim 1.

Die Herstellung von Schutzgas für die Wärmebehandlung von Metallen erfolgt herkömmlich in Generatoren durch Verbrennung kohlenwasserstoffhaltiger Brenngase. Diese Herstellungsart ist sehr aufwendig. Eine kostengünstigere Alternative bietet die Reaktion in Mantelstrahlrohren, die mit Hilfe von Katalysatoren durchgeführt wird.Protective gas for the heat treatment of metals is conventionally produced in generators by burning combustion gases containing hydrocarbons. This type of production is very complex. A cheaper alternative is the reaction in jacket pipes, which is carried out with the help of catalysts.

Diese Alternative erfordert bei unterstöchiometrischer Verbrennung zur Herstellung von Endogas die Verbrennung unter äußerer Wärmezufuhr.In the case of substoichiometric combustion for the production of endogas, this alternative requires combustion with external heat input.

Mantelstrahlrohre dienen im Industrieofenbau zur Behei­zung von Warmbehandlungsanlagen mit künstlichen Atmosphären. Sie können mit Gas oder elektrisch beheizt werden. Ein Mantelstrahlrohr besteht im wesentlichen aus drei Rohren, nämlich dem äußeren Mantelrohr zur Be­heizung des Ofenraumes, dem Innen- oder Brennrohr, in dem die Verbrennung stattfindet und dem Gaszuleitungsrohr zum Verbrennungsraum im Brennrohr. Eine unterstöchiome­trische Verbrennung im Mantelstrahlrohr ergäbe zwar reduzierende Bestandteile im Abgas (Schutzgas), würde aber zu Verrußungen und zum Durchbrennen der Rohre führen. Eine weitere Möglichkeit zur Schutzgaserzeugung ist das Einsprühen von Stickstoff-Methanolgemischen in den Glüh­ofen. Bei Temperaturen oberhalb 750°C zersetzt sich das Methanol hierbei nach der Gleichung
CH₃ OH → 2H₂ + CO.Sheathed jet pipes are used in industrial furnace construction to heat heat treatment systems with artificial atmospheres. They can be heated with gas or electrically. A jacket jet pipe consists essentially of three pipes, namely the outer jacket pipe for heating the furnace chamber, the inner or combustion pipe in which the combustion takes place and the gas supply pipe to the combustion chamber in the combustion pipe. A substoichiometric combustion in the jacket jet pipe would result in reducing components in the exhaust gas (protective gas), but would lead to sooting and to the burning of the pipes. Another way of generating protective gas is to spray nitrogen-methanol mixtures into the annealing furnace. At temperatures above 750 ° C, the methanol decomposes according to the equation
CH₃ OH → 2H₂ + CO.

Insbesondere zum Aufkohlen kann diesem Spaltgas noch ein Aufkohlungsmittel wie Propan oder Erdgas zugemischt wer­den. Diese Art der Schutzgaserzeugung ist zwar sehr preis­wert, setzt aber einen fremdbeheizten Glühofen mit Be­triebstemperaturen oberhalb 750°C voraus. Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren zu schaffen, welches die Schutzgasherstellung durch Verbrennung eines kohlenwasserstoffhaltigen Brenngases in einem Mantelstrahl­rohr auch in solchen Fällen ermöglicht, in denen an sich eine unterstöchiometrische Verbrennung bei Ofentemperatu­ren unterhalb 750°C erforderlich ist und keine äußere Wärmezufuhr erfolgt.In particular for carburizing, a carburizing agent such as propane or natural gas can also be added to this cracked gas. This type of protective gas production is very inexpensive, but it requires an externally heated annealing furnace with operating temperatures above 750 ° C. The invention has for its object to provide a method which enables the production of protective gas by burning a hydrocarbon-containing fuel gas in a jacket jet tube even in those cases in which a substoichiometric combustion at furnace temperatures below 750 ° C is required and no external heat is supplied.

Insbesondere gilt dies für Buntmetallöfen, bei denen der Einsatz von reduzierenden Wasserstoff-Stickstoff-­Gemischen zu teuer ist.This applies in particular to non-ferrous metal furnaces where the use of reducing hydrogen-nitrogen mixtures is too expensive.

Ausgehend von dem im Oberbegriff des Anspruches 1 be­rücksichtigten Stand der Technik ist diese Aufgabe er­findungsgemäß gelöst mit den im kennzeichnenden Teil des Anspruches 1 angegebenen Merkmalen.Starting from the prior art taken into account in the preamble of claim 1, this object is achieved according to the invention with the features specified in the characterizing part of claim 1.

Vorteilhafte Weiterbildungen sind in den Unteransprüchen angegeben.Advantageous further developments are specified in the subclaims.

Die Erfindung beruht auf der Erkenntnis, daß es möglich ist, in den Verbrennungsraum eines mit einem stöchio­metrischen Verhältnis von χ gleich oder nahe 1 be­triebenen Mantelstrahlrohres ein Stickstoff-Methanolge­misch in genügend großer Menge einzuspeisen, um einer­seits eine gewünschte Schutzgasatmosphäre zu erhalten, ohne daß andererseits eine Ofentemperatur von 750°C erforderlich wird. Im Mantelstrahlrohr herrschen bei stöchiometrischer Verbrennung dagegen immer Temperaturen über 750°C.The invention is based on the knowledge that it is possible to feed a nitrogen-methanol mixture in a sufficient quantity into the combustion chamber of a jacket jet pipe operated with a stoichiometric ratio of χ equal to or close to 1, on the one hand to obtain a desired protective gas atmosphere without on the other hand Oven temperature of 750 ° C is required. In the case of stoichiometric combustion, on the other hand, the jacket jet always has temperatures above 750 ° C.

Die Vorteile des erfindungsgemäßen Verfahrens liegen vor allem beim Glühen von Buntmetall, weil es eine kostengünstige Alternative zu generatorerzeugtem Schutz­gas und zu Wasserstoff-Stickstoff-Gemischen bietet. Das erfindungsgemäße Verfahren eignet sich auch zum Blankglühen von Stahl, allerdings muß hierbei eine Trocknung nachgeschaltet werden.The advantages of the method according to the invention lie above all in the annealing of non-ferrous metal, because it offers an inexpensive alternative to protective gas generated by the generator and to hydrogen-nitrogen mixtures. The method according to the invention is also suitable for bright annealing steel, but drying must be carried out afterwards.

Ein Ausführungsbeispiel der Erfindung soll anhand der beigefügten Zeichnung erläutert werden.An embodiment of the invention will be explained with reference to the accompanying drawings.

In der Zeichnung ist in sehr vereinfachter Form ein Mantelstrahlrohr dargestellt, in welchem Erdgas mit Luft zur Schutzgaserzeugung verbrannt wird.In the drawing, a jacket jet is shown in a very simplified form, in which natural gas is burned with air to generate protective gas.

Das Erdgas wird durch ein Gaszuleitungsrohr 1 zugeführt, welches konzentrisch vom Brennrohr 2 umgeben ist. Durch das Brennrohr 2 strömt die Verbrennungsluft, welche mit dem Erdgas im Vebrennungsraum 3 die Flamme 4 bildet. Hierbei ist ein stöchiometrisches Brennstoff-Luft-­Verhältnis von χ = 1 eingestellt. Das Brennrohr 2 wird konzentrisch vom Mantelrohr 5 allseitig umgeben, läßt aber den Austritt aus dem Brennrohr 2 frei. Die Rauch­gase strömen daher außerhalb des Brennrohres 2 zurück und verlassen das Mantelstrahlrohr durch den Stutzen 6 als Schutzgas, welches direkt mit hoher Temperatur in den Ofen gelangt.The natural gas is supplied through a gas supply pipe 1, which is surrounded concentrically by the combustion pipe 2. The combustion air flows through the combustion tube 2 and forms the flame 4 with the natural gas in the combustion chamber 3. Here, a stoichiometric fuel-air ratio of χ = 1 is set. The fuel tube 2 is surrounded concentrically on all sides by the jacket tube 5, but leaves the outlet from the fuel tube 2 free. The flue gases therefore flow back outside the combustion tube 2 and leave the jacket jet pipe through the nozzle 6 as a protective gas, which reaches the furnace directly at high temperature.

Erfindungsgemäß wird ein Stickstoff-Methanolgemisch in den Verbrennungsraum 3 eingesprüht. Hierzu dient das Sprührohr 7, welches innerhalb des Brennrohres 2 parallel zum Gaszuleitungsrohr 1 angeordnet ist und kurz vor dem Verbrennungsraum 3 mündet. Die Stickstoff-Methanolmenge wird dabei so bemessen, daß die Verbrennungstemperatur im Verbrennungsraum 3 nicht unter 750°C sinkt. Das Methanol könnte auch in reiner Form mittels einer Pumpe in das Mantelstrahlrohr gefördert und in den Verbrennungs­raum 3 gesprüht werden. Eine ausreichend feine Verteilung des Methanols läßt sich hierbei jedoch nur schwer errei­chen, weshalb die Zufuhr eines Stickstoff-Methanol-Ge­misches bei weitem vorzuziehen ist.According to the invention, a nitrogen-methanol mixture is sprayed into the combustion chamber 3. The spray tube 7, which is arranged inside the combustion tube 2 parallel to the gas supply tube 1 and opens shortly before the combustion chamber 3, serves this purpose. The amount of nitrogen-methanol is measured so that the combustion temperature in combustion chamber 3 does not drop below 750 ° C. The methanol could also be pumped into the jacket tube in pure form and sprayed into the combustion chamber 3. However, it is difficult to achieve a sufficiently fine distribution of the methanol, which is why the addition of a nitrogen-methanol mixture is far preferable.

Nachfolgend ein Zahlenbeispiel:
4m³/h Erdgas der Zusammensetzung 81,3% CH₄, 14,4% N₂, 3,5% Cn/Hm und 0,8% CO₂ werden mit 33,52 m³/h Luft in dem in der Zeichnung dargestellten Mantelstrahlrohr ver­brannt. Hierbei entstehen 37,452 m³/h Abgas, bestehend aus 3,628 m³/h CO₂, 6,848 m³/h H₂O und 26,976 m³N₂.Below is a numerical example:
4m³ / h natural gas of the composition 81.3% CH₄, 14.4% N₂, 3.5% Cn / Hm and 0.8% CO₂ are burned with 33.52 m³ / h air in the jacket pipe shown in the drawing. This creates 37.452 m³ / h exhaust gas, consisting of 3.628 m³ / h CO₂, 6.848 m³ / h H₂O and 26.976 m³N₂.

Die Verbrennungstemperatur im Verbrennungsraum 3 be­trägt hierbei ca. 850°C.The combustion temperature in combustion chamber 3 is approximately 850 ° C.

Erfindungsgemäß werden durch das Sprührohr 7 4 l/h Methanol mit 4m³/h N₂ in den Verbrennungsraum 3 einge­sprüht. Hierbei zersetzt sich das Methanol zu H₂ und CO. Der Wasserstoff reagiert gleichzeitig gemäß der Wasser­gasreaktion H₂ + CO₂ ⇄ H₂O + CO mit dem Verbrennungs­produkt CO₂, so daß schließlich 37m³/h Abgas mit folgen­der Zusammensetzung in Vol.% erhalten wird: 7,2% CO₂ 9,1% H₂ 5,0% CO 14,5% H₂O 64,2% N₂ According to the invention, 4 l / h of methanol with 4 m 3 / h of N 2 are sprayed into the combustion chamber 3 through the spray tube 7. Here, the methanol decomposes to H₂ and CO. The hydrogen reacts simultaneously with the water gas reaction H₂ + CO₂ ⇄ H₂O + CO with the combustion product CO₂, so that 37m³ / h exhaust gas with the following composition in volume% is finally obtained: 7.2% CO₂ 9.1% H₂ 5.0% CO 14.5% H₂O 64.2% N₂

Dieses Gas wird mit 100m³/h Stickstoff vermischt. Dieser Stickstoff wird flüssig in die Kühlstrecke eingesprüht, um die Temperatur zu senken. Es ergibt sich zum Glühen eine Schutzgasatmosphäre mit folgender Zusammensetzung: 1,9% CO₂ 2,5% H₂ 1,4% CO 3,9% H₂O 90,3% N₂ This gas is mixed with 100m³ / h nitrogen. This nitrogen is sprayed into the cooling section in liquid form in order to lower the temperature. A protective gas atmosphere with the following composition results for the annealing: 1.9% CO₂ 2.5% H₂ 1.4% CO 3.9% H₂O 90.3% N₂

Mit diesem Schutzgas kann beispielsweise Kupfer blankge­glüht werden.With this shielding gas, for example, copper can be bright annealed.

Claims (3)

1. Verfahren zur Herstellung eines Schutzgases für die Wärmebehandlung von Eisen und Nichteisenmetallen, bei dem ein kohlenwasserstoffhaltiges Brenngas in einem Mantelstrahlrohr mit Luft verbrannt, mit verdampftem Methanol ohne Katalysator zur Reaktion gebracht und das auf diese Weise gebildete Abgas für die Erzeugung des Schutzgases verwendet wird,
dadurch gekennzeichnet,
daß ein Gemisch aus Stickstoff und Methanol in den Verbrennungsraum (3) des Mantelstrahlrohres einge­sprüht wird.1. A process for producing a protective gas for the heat treatment of iron and non-ferrous metals, in which a hydrocarbon-containing fuel gas is burned with air in a jacket jet tube, reacted with evaporated methanol without a catalyst and the exhaust gas thus formed is used for the production of the protective gas,
characterized,
that a mixture of nitrogen and methanol is sprayed into the combustion chamber (3) of the jacket jet. 2. Verfahren nach Anspruch 1,
dadurch gekennzeichnet,
daß eine Verbrennungstemperatur von 750°C im Mantel­strahlrohr nicht unterschritten wird.2. The method according to claim 1,
characterized,
that the combustion temperature in the jacket jet pipe does not fall below 750 ° C. 3. Verfahren nach Anspruch 1 oder 2,
dadurch gekennzeichnet,
daß die Verbrennung des kohlenwasserstoffhaltigen Brenngases bei einem stöchiometrischen Verhältnis von χ = 1 erfolgt.3. The method according to claim 1 or 2,
characterized,
that the combustion of the hydrocarbon-containing fuel gas takes place at a stoichiometric ratio of χ = 1.
EP89102430A 1988-03-11 1989-02-13 Method for producing a protective atmosphere for heat treating ferrous and non-ferrous metals Expired - Lifetime EP0331929B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89102430T ATE78877T1 (en) 1988-03-11 1989-02-13 PROCESS FOR THE PREPARATION OF A SHIELD GAS FOR THE HEAT TREATMENT OF FERROUS AND NON-FERROUS METALS.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3808146 1988-03-11
DE3808146A DE3808146A1 (en) 1988-03-11 1988-03-11 METHOD FOR PRODUCING A PROTECTIVE GAS FOR THE HEAT TREATMENT OF IRON AND NON-FERROUS METALS

Publications (2)

Publication Number Publication Date
EP0331929A1 true EP0331929A1 (en) 1989-09-13
EP0331929B1 EP0331929B1 (en) 1992-07-29

Family

ID=6349493

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89102430A Expired - Lifetime EP0331929B1 (en) 1988-03-11 1989-02-13 Method for producing a protective atmosphere for heat treating ferrous and non-ferrous metals

Country Status (3)

Country Link
EP (1) EP0331929B1 (en)
AT (1) ATE78877T1 (en)
DE (1) DE3808146A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103805759A (en) * 2012-11-01 2014-05-21 财团法人金属工业研究发展中心 Furnace gas generating device for small heat treatment furnace

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4308803A1 (en) * 1993-03-19 1994-09-22 Leybold Durferrit Gmbh Process and appliance for producing a carbon-containing gaseous treatment atmosphere
DE19536706A1 (en) * 1995-10-02 1997-04-03 Lbe Beheizungseinrichtungen Jacketed radiant heating tube e.g. for industrial furnace

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1106787B (en) * 1956-04-26 1961-05-18 Renault Device for feeding a group of heat treatment furnaces for metals with protective gas from vapors of organic liquids which are enriched with nitrogen
US4139375A (en) * 1978-02-06 1979-02-13 Union Carbide Corporation Process for sintering powder metal parts
EP0049488A1 (en) * 1980-10-04 1982-04-14 Linde Aktiengesellschaft Method of and apparatus for decarburizing or neutrally annealing metal workpieces
DE3104280A1 (en) * 1981-02-07 1982-08-12 Daimler-Benz Ag, 7000 Stuttgart Process for generating protective gas from the off-gas of furnaces heated by radiant tubes
GB2145503A (en) * 1983-08-24 1985-03-27 Golding Ivor Lawrence Sydney Process of producing protective atmosphere in heat treatment furnaces and ovens
DE3422608A1 (en) * 1984-06-18 1985-12-19 Linde Ag, 6200 Wiesbaden Process and apparatus for producing a gas atmosphere containing carbon monoxide and hydrogen

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1106787B (en) * 1956-04-26 1961-05-18 Renault Device for feeding a group of heat treatment furnaces for metals with protective gas from vapors of organic liquids which are enriched with nitrogen
US4139375A (en) * 1978-02-06 1979-02-13 Union Carbide Corporation Process for sintering powder metal parts
EP0049488A1 (en) * 1980-10-04 1982-04-14 Linde Aktiengesellschaft Method of and apparatus for decarburizing or neutrally annealing metal workpieces
DE3104280A1 (en) * 1981-02-07 1982-08-12 Daimler-Benz Ag, 7000 Stuttgart Process for generating protective gas from the off-gas of furnaces heated by radiant tubes
GB2145503A (en) * 1983-08-24 1985-03-27 Golding Ivor Lawrence Sydney Process of producing protective atmosphere in heat treatment furnaces and ovens
DE3422608A1 (en) * 1984-06-18 1985-12-19 Linde Ag, 6200 Wiesbaden Process and apparatus for producing a gas atmosphere containing carbon monoxide and hydrogen

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103805759A (en) * 2012-11-01 2014-05-21 财团法人金属工业研究发展中心 Furnace gas generating device for small heat treatment furnace
CN103805759B (en) * 2012-11-01 2016-01-20 财团法人金属工业研究发展中心 Furnace gas generating device for small heat treatment furnace

Also Published As

Publication number Publication date
EP0331929B1 (en) 1992-07-29
ATE78877T1 (en) 1992-08-15
DE3808146A1 (en) 1989-09-21

Similar Documents

Publication Publication Date Title
DE1433735B1 (en) Process for achieving a furnace atmosphere with which an oxidation-free heat treatment of workpieces made of steel can be carried out while at the same time influencing the carbon content
EP0331929B1 (en) Method for producing a protective atmosphere for heat treating ferrous and non-ferrous metals
EP0261461B1 (en) Method and apparatus for heat treating metal work pieces
EP0430313B1 (en) Method and device for producing a protective atmosphere
EP0703994B1 (en) Method and device for the heat treatment of workpieces
EP0049488B1 (en) Method of and apparatus for decarburizing or neutrally annealing metal workpieces
DE3422608C2 (en)
EP0794263B1 (en) Method for producing a protective atmosphere for heat treatment furnace and heat treatment apparatus
DE632935C (en) Process and device for surface carbonization of iron and steel
DE4308803A1 (en) Process and appliance for producing a carbon-containing gaseous treatment atmosphere
DE2419997C2 (en) Method and device for producing hardenable or wear-resistant surface layers of steel parts in an annealing furnace
DE2822048C2 (en) Plant for the generation of treatment gas for the treatment of metallic objects
DE10012051A1 (en) Process for recovering heat in high temperature processes comprises reacting in a reformer a partial stream of gaseous or liquid fuel with a partial stream of hot combustion gases in an endothermic gasification reaction to form a fuel gas
EP0364709B1 (en) Method of producing a gas-annealing atmosphere in a heat-treating device
DE3231699C2 (en) Method and device for producing a blackening or bluish oxide layer on the surface of iron-containing parts produced by powder metallurgy
DE641596C (en) Process for the production of mixtures of nitrogen and hydrogen that are practically free of oxygen and nitrogen oxide
DE14196C (en) Innovations in the creation of a rust-proof cover on objects made of iron and steel together with the ovens used for them
DE365893C (en) Process for the oxidation of tin
EP0096104A1 (en) Process for producing a gas atmosphere that contains nitrogen and hydrogen
DE2524177A1 (en) Hot reducing gas prodn. for ore redn. - esp. by plasma heating of steel making off-gases
DE868437C (en) The use of coke oven gas or similar gas as heating gas for industrial furnaces, e.g. B. Siemens-Martin-OEfen
DE19618277A1 (en) Highly reactive gas production at low pressure and temperature for diverse surface treatments or chemical reactions
DE19707470A1 (en) Process for generating treatment gas for the heat treatment of metallic goods
DE10051203A1 (en) Production of a treatment gas containing carbon monoxide and hydrogen used for heat treating metallic material comprises heating a gas mixture containing oxygen and nitrogen
DE3224607A1 (en) Method for the case-hardening and neutral-carburising annealing of metal workpieces

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT FR GB IT

17P Request for examination filed

Effective date: 19900219

17Q First examination report despatched

Effective date: 19910806

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT FR GB IT

REF Corresponds to:

Ref document number: 78877

Country of ref document: AT

Date of ref document: 19920815

Kind code of ref document: T

ITF It: translation for a ep patent filed

Owner name: DE DOMINICIS & MAYER S.

ET Fr: translation filed
GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19950203

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19950210

Year of fee payment: 7

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 19950214

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19960213

Ref country code: AT

Effective date: 19960213

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19960213

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19961031

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20050213