EP0331929B1 - 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 PDFInfo
- Publication number
- EP0331929B1 EP0331929B1 EP89102430A EP89102430A EP0331929B1 EP 0331929 B1 EP0331929 B1 EP 0331929B1 EP 89102430 A EP89102430 A EP 89102430A EP 89102430 A EP89102430 A EP 89102430A EP 0331929 B1 EP0331929 B1 EP 0331929B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- combustion
- gas
- protective gas
- methanol
- 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.)
- Expired - Lifetime
Links
- 230000001681 protective effect Effects 0.000 title claims abstract description 17
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 7
- 239000002184 metal Substances 0.000 title claims abstract description 7
- 238000004519 manufacturing process Methods 0.000 title abstract description 8
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 title description 3
- -1 ferrous metals Chemical class 0.000 title description 3
- 238000002485 combustion reaction Methods 0.000 claims abstract description 32
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 30
- 239000007789 gas Substances 0.000 claims abstract description 29
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 13
- 239000000203 mixture Substances 0.000 claims abstract description 11
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 6
- 239000002737 fuel gas Substances 0.000 claims abstract description 4
- 150000002739 metals Chemical class 0.000 claims abstract description 3
- 238000000034 method Methods 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 4
- 229930195733 hydrocarbon Natural products 0.000 claims description 4
- 150000002430 hydrocarbons Chemical class 0.000 claims description 4
- 239000004215 Carbon black (E152) Substances 0.000 claims description 3
- 239000003054 catalyst Substances 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims description 2
- 238000005507 spraying Methods 0.000 claims 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 abstract description 13
- 239000003345 natural gas Substances 0.000 abstract description 6
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 abstract description 4
- 239000001294 propane Substances 0.000 abstract description 2
- LBPGGVGNNLPHBO-UHFFFAOYSA-N [N].OC Chemical compound [N].OC LBPGGVGNNLPHBO-UHFFFAOYSA-N 0.000 description 5
- 238000000137 annealing Methods 0.000 description 5
- 239000000446 fuel Substances 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 238000005255 carburizing Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000000567 combustion gas Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 150000002829 nitrogen Chemical class 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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.
- 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.
- Mantle jet tubes 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 pipes burning.
- 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 CH3DH ⁇ 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.
- From DE-A-3 422 608 it is also known to produce a protective gas from nitrogen and methanol with the aid of a jacket jet pipe, by decomposing the methanol in a space heated by the jet pipe and shielded from the furnace atmosphere and together with the nitrogen is passed into the furnace interior.
- the jet pipe is heated electrically or by burning a fuel.
- the invention has for its object to provide a method which enables the production of inert gas by combustion of a hydrocarbon-containing fuel gas in a jacket jet tube even in those cases in which no external heat is supplied.
- the invention is based on the knowledge that it is possible to feed a nitrogen-methanol mixture in sufficient quantity into the combustion chamber of a jacket jet tube 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.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Coating By Spraying Or Casting (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren zur Herstellung eines Schutzgases für die Wärmebehandlung von Eisen und Nichteisenmetallen.The invention relates to a method for producing a protective gas for the heat treatment of iron and non-ferrous metals.
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.
Mantelstrahlrohe 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
CH₃DH → 2H₂ + CO.
Mantle jet tubes 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 pipes burning. 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
CH₃DH → 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. Aus der DE-A-3 422 608 ist es ferner bekannt ein Schutzgas aus Stickstoff und Methanol mit Hilfe eines Mantelstrahlrohres herzustellen, indem das Methanol in einem vom Strahlrohr erhitzten und gegen die Ofenatmosphäre abgeschirmten Raum zersetzt und zusammen mit dem Stickstoff in den Ofeninnenraum geleitet wird. Das Strahlrohr wird hierbei elektrisch oder durch Verbrennen eines Brennstoffes beheizt.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. From DE-A-3 422 608 it is also known to produce a protective gas from nitrogen and methanol with the aid of a jacket jet pipe, by decomposing the methanol in a space heated by the jet pipe and shielded from the furnace atmosphere and together with the nitrogen is passed into the furnace interior. The jet pipe is heated electrically or by burning a fuel.
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 keine äußere Wärmezufuhr erfolgt.The invention has for its object to provide a method which enables the production of inert gas by combustion of a hydrocarbon-containing fuel gas in a jacket jet tube even in those cases in which 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.
Das oben genannte Problem wird durch die Merkmale des Anspruchs 1 gelöst. Bevorzugte Lösungen sind in den abhängigen Ansprüchen 2 und 3 offenbart.The above problem is solved by the features of claim 1. Preferred solutions are disclosed in
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 sufficient quantity into the combustion chamber of a jacket jet tube 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
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
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 m³/h N₂.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 produces 37.452 m³ / h exhaust gas, consisting of 3.628 m³ / h CO₂, 6.848 m³ / h H₂O and 26.976 m³ / h N₂.
Die Verbrennungstemperatur im Verbrennungsraum 3 beträgt hierbei ca. 850°C.The combustion temperature in
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
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)
characterised in that
the combustion temperature does not fall below 750°C in the jacketed jet pipe.
characterised in that
the combustion of the hydrocarbon-containing fuel gas takes place in a stoichiometric ratio of χ = 1.
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 EP0331929A1 (en) | 1989-09-13 |
| EP0331929B1 true 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) |
Families Citing this family (3)
| 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 |
| TW201418476A (en) * | 2012-11-01 | 2014-05-16 | Metal Ind Res & Dev Ct | Furnace gas generation apparatus used in small heat treatment furnace |
Family Cites Families (6)
| 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 |
| DE3037643A1 (en) * | 1980-10-04 | 1982-05-13 | Linde Ag, 6200 Wiesbaden | METHOD AND DEVICE FOR THE DECOLARIZING OR COAL-NEUTRAL GLOWING OF METAL PARTS |
| DE3104280C2 (en) * | 1981-02-07 | 1982-10-21 | Daimler-Benz Ag, 7000 Stuttgart | Process for generating protective gas from the exhaust gas from radiant tube-heated ovens |
| GB2145503B (en) * | 1983-08-24 | 1987-03-11 | 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 |
-
1988
- 1988-03-11 DE DE3808146A patent/DE3808146A1/en not_active Withdrawn
-
1989
- 1989-02-13 EP EP89102430A patent/EP0331929B1/en not_active Expired - Lifetime
- 1989-02-13 AT AT89102430T patent/ATE78877T1/en active
Also Published As
| Publication number | Publication date |
|---|---|
| DE3808146A1 (en) | 1989-09-21 |
| ATE78877T1 (en) | 1992-08-15 |
| EP0331929A1 (en) | 1989-09-13 |
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