EP0953654A1 - Process and apparatus for gas carburising - Google Patents
Process and apparatus for gas carburising Download PDFInfo
- Publication number
- EP0953654A1 EP0953654A1 EP99108094A EP99108094A EP0953654A1 EP 0953654 A1 EP0953654 A1 EP 0953654A1 EP 99108094 A EP99108094 A EP 99108094A EP 99108094 A EP99108094 A EP 99108094A EP 0953654 A1 EP0953654 A1 EP 0953654A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- ethanol
- carbon dioxide
- atmosphere
- carburizing
- carbon
- 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
Links
- 238000000034 method Methods 0.000 title claims description 15
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 55
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 50
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 25
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 25
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 15
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 15
- 238000005255 carburizing Methods 0.000 claims description 20
- 230000015572 biosynthetic process Effects 0.000 claims description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 239000004215 Carbon black (E152) Substances 0.000 claims description 2
- 229930195733 hydrocarbon Natural products 0.000 claims description 2
- 150000002430 hydrocarbons Chemical class 0.000 claims description 2
- 238000005259 measurement Methods 0.000 claims description 2
- 238000005755 formation reaction Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 4
- 238000000889 atomisation Methods 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
- OSQPUMRCKZAIOZ-UHFFFAOYSA-N carbon dioxide;ethanol Chemical compound CCO.O=C=O OSQPUMRCKZAIOZ-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/20—Carburising
Definitions
- the invention relates to a method for carburizing metallic workpieces in a furnace at high temperatures and in an atmosphere containing CO and H 2 , in which the atmosphere is formed by reacting an oxygen-containing hydrocarbon medium, in particular an alcohol, with carbon dioxide.
- the invention proposes that the atmosphere is specially formed on the basis of ethanol and carbon dioxide and the arrival or Depletion of the atmosphere, i.e. the setting of a certain carbon level, by adjusting the stoichiometric ratio accordingly of ethanol and carbon dioxide.
- this primarily results in an atmosphere formation reaction in accordance with C 2 H 5 OH + CO 2 ---> 3 CO + 3 H 2 .
- the accumulation or reaction of the water and carbon dioxide produced in the carburizing process which is usually achieved by CH 4 or C 3 H 8 , is achieved according to the invention by adjusting the stoichiometric ratio of ethanol and carbon dioxide, because an excess of ethanol results in 2 C 2 H 5 OH + 1 CO 2 ---> CH 4 + 2 CO + 2 CO + 4 H 2 also a methane content in the product gas, which takes over the task of the enrichment gas, which is otherwise supplied independently.
- the preparation of an enrichment gas is therefore not necessary in the method according to the invention.
- an atmospheric gas with a CO to H 2 ratio of exactly 1: 1 is produced, which primarily serves to accelerate carburization.
- the ethanol-carbon dioxide system with regard to its reaction properties offers favorable conditions. It already reacts at about 800 ° C in the desired manner and ethanol and carbon dioxide can therefore - according a preferred process variant - for atmospheric formation without further measures directly into a carburizing furnace. A practice with a standalone atmosphere generator can still work in some Applications may be required.
- the system "ethanol and carbon dioxide” also results in a two-component system, that is comparatively easy to regulate.
- the procedure is such that the carbon level in the carburizing furnace is measured continuously and the adjustment of the stoichiometric ratio of ethanol and changing carbon dioxide according to the desired carbon level.
- Atmospheric formation one component is constantly fed into the system, and the other, depending on a carbon level measurement, supplied in a controlled manner becomes.
- a carburizing plant according to the invention is characterized in that the associated carburizing furnace for the purpose of atmosphere formation only an ethanol source (A) and a carbon dioxide source (C) served and therefore with this is connected, and that a measuring device (M) for measuring the carbon level is present in the furnace, which in turn has a quantity control unit in the ethanol feed line and / or the carbon dioxide feed line is connected.
- the invention is explained in more detail below in connection with the attached figure using an exemplary embodiment.
- the figure shows a system design according to the invention with regulated CO 2 supply.
- a carburizing furnace O is first to be coupled to an ethanol source A and to a carbon dioxide source C via suitable lines and actuators.
- the ethanol supply consists of an ethanol pump P and a line 1, which opens into a atomization unit V before reaching the carburizing furnace.
- a carbon dioxide feed line 2d likewise opens into the atomization unit.
- the carbon dioxide feed line 2d divides upstream of the atomization unit V into a parallel circuit section with two lines 2b and 2c, in each of which there is an actuator - S1 and S2 - for quantity control.
- the parallel connection is connected to the CO 2 source C via a line section 2a and a main valve H.
- the carburizing furnace O is equipped with a measuring device M for measuring the carbon level in its interior.
- the measuring device M in turn is connected to a control device S, which in turn acts on the actuator S2 in the bypass line 2c of the parallel connection.
- a procedure according to the invention of this system consists in that the starting media ethanol and carbon dioxide are introduced in certain basic quantities into the furnace O which is at a temperature and which are determined by suitable adjustment of the pumping power of the ethanol pump P and of the actuator S1.
- the feed quantities are to be set so that one mole of ethanol comes to one mole of CO 2 , with an excess of ethanol generally being provided in the variant shown.
- an atmosphere containing essentially 1: 1 CO and H 2 is formed from these starting media, the carbon level of which is determined by the measuring device M, for example an oxygen probe or a C-flow probe. Since in the described case, in principle an excess of ethanol is used, a relatively high C level arises in the basic setting of the system.
- the correspondingly programmed control device S triggers the opening of the actuator S2 and thus increases the CO 2 supply. As a result, the C level drops until, when a lower limit to be defined is reached, actuator S2 is closed again. In this way, a relatively simple, extremely efficient, C-level controlled carburizing atmosphere is obtained.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Treating Waste Gases (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren zur Aufkohlung metallischer Werkstücke in einem Ofen unter hohen Temperaturen und in einer CO und H2 enthaltenden Atmosphäre, bei dem die Atmosphäre durch Umsetzung eines sauerstoffhaltigen Kohlenwasserstoffmediums, insbesondere eines Alkohols, mit Kohlendioxid gebildet wird.The invention relates to a method for carburizing metallic workpieces in a furnace at high temperatures and in an atmosphere containing CO and H 2 , in which the atmosphere is formed by reacting an oxygen-containing hydrocarbon medium, in particular an alcohol, with carbon dioxide.
Es ist aus der DE-PS 43 40 060 ein Verfahren zur Aufkohlung metallischer Werkstücke in einem Ofen unter hohen Temperaturen und in einer CO und H2 enthaltenden Atmosphäre bekannt, bei dem die Atmosphäre zumindest zu Beginn der Aufkohlung auf der Basis eines dem Ofen zugeführten Alkohols und Kohlendioxid gebildet wird, wobei zusätzlich auch ein Anreicherungsmittel zur Einstellung eines bestimmten Kohlenstoffpegels und teilweise auch zur Atmosphärenbildung einzubringen ist. Mit diesem Verfahren kann eine stickstofffreie Aufkohlungsatmosphäre mit einem CO-zu-H2-Verhältnisses von etwa 1:1 und damit sehr guten Aufkohlungseigenschaften erzielt werden. Nachteilig bei diesem Verfahren sind die relativ komplizierten Regel- oder Steuerprozesse für die drei zugehörigen Medien, worin auch die Problemstellung der vorliegenden Erfindung bestand.It is known from DE-PS 43 40 060 a method for carburizing metallic workpieces in a furnace at high temperatures and in an atmosphere containing CO and H 2 , in which the atmosphere, at least at the beginning of carburizing, is based on an alcohol supplied to the furnace and carbon dioxide is formed, an enrichment agent for adjusting a certain carbon level and sometimes also for atmospheric formation also having to be introduced. With this process, a nitrogen-free carburizing atmosphere with a CO to H 2 ratio of about 1: 1 and thus very good carburizing properties can be achieved. A disadvantage of this method is the relatively complicated regulation or control processes for the three associated media, which was also the problem with the present invention.
Zur Lösung dieses Problems wird erfindungsgemäß vorgeschlagen, daß die Atmosphäre auf der Basis speziell von Äthanol und Kohlendioxid gebildet wird und die An- oder Abreichetung der Atmosphäre, also die Einstellung eines bestimmten Kohlenstoffpegels, durch entsprechende Verstellung des stöchiometrischen Verhältnisses von Äthanol und Kohlendioxid erzielt wird.To solve this problem, the invention proposes that the atmosphere is specially formed on the basis of ethanol and carbon dioxide and the arrival or Depletion of the atmosphere, i.e. the setting of a certain carbon level, by adjusting the stoichiometric ratio accordingly of ethanol and carbon dioxide.
Erfindungsgemäß ergibt sich somit in erster Linie eine Atmosphärenbildungsreaktion
gemäß
Es wird also eine Atmosphäre mit einem CO-zu-H2-Verhältnis von 1:1 erzielt, also dem für Aufkohlungen optimalen Verhältnis, das eine maximale Kohlenstoffübergangszahl ß zur Folge hat. An atmosphere with a CO to H 2 ratio of 1: 1 is thus achieved, that is to say the optimum ratio for carburization, which results in a maximum carbon transition number β.
Die üblicherweise durch CH4 oder C3H8 erreichte Anreicherung bzw. Abreaktion des
beim Aufkohlungsprozeß entstehenden Wassers und Kohlendioxids wird erfindungsgemäß
durch Verstellung des stöchiometrischen Verhältnisses von Äthanol und Kohlendioxid
erreicht, denn bei einem Überangebot von Äthanol entsteht gemäß
Hinzu kommt, daß das Äthanol-Kohlendioxid-System hinsichtlich seiner Reaktionseigenschaften günstige Verhältnisse bietet. Es reagiert nämlich bereits bei etwa 800°C in gewünschter Weise und Äthanol und Kohlendioxid können daher - gemäß einer bevorzugten Verfahrensvariante - zur Atmosphärenbildung ohne weitere Maßnahmen direkt in einen Aufkohlungsofen eingebracht werden. Eine Verfahrensweise mit einem eigenständigen Atmosphären-Generator kann jedoch dennoch in einigen Einsatzfällen erforderlich sein.In addition, the ethanol-carbon dioxide system with regard to its reaction properties offers favorable conditions. It already reacts at about 800 ° C in the desired manner and ethanol and carbon dioxide can therefore - according a preferred process variant - for atmospheric formation without further measures directly into a carburizing furnace. A practice with a standalone atmosphere generator can still work in some Applications may be required.
Mit dem System "Äthanol und Kohlendioxid" ergibt sich ferner ein Zweikomponentensystem, das vergleichsweise einfach regelbar ist. In einer vorteilhaften Ausgestaltung wird derart verfahren, daß der Kohlenstoffpegel im Aufkohlungsofen fortlaufend gemessen wird und die Verstellung des stöchiometrischen Verhältnisses von Äthanol und Kohlendioxid entsprechend dem gewünschten Kohlenstoffpegel verändert wird. Insbesondere ist es vorteilhaft, wenn bei der Ausgestaltung der erfindungsgemäßen Atmosphärenbildung immer eine Komponente konstant in die Anlage gespeist wird, und die andere, abhängig von einer Kohlenstoffpegelmessung, geregelt zugeleitet wird.The system "ethanol and carbon dioxide" also results in a two-component system, that is comparatively easy to regulate. In an advantageous embodiment The procedure is such that the carbon level in the carburizing furnace is measured continuously and the adjustment of the stoichiometric ratio of ethanol and changing carbon dioxide according to the desired carbon level. In particular, it is advantageous if in the configuration of the invention Atmospheric formation, one component is constantly fed into the system, and the other, depending on a carbon level measurement, supplied in a controlled manner becomes.
Eine Aufkohlungsanlage gemäß der Erfindung ist dadurch gekennzeichnet, daß der zugehörige Aufkohlungsofen zum Zweck der Atmosphärenbildung sich ausschließlich einer Äthanolquelle (A) und einer Kohlendioxidquelle (C) bedient und demzufolge mit diesen verbunden ist, und daß ein Meßgerät (M) zur Messung des Kohlenstoffpegels im Ofen vorhanden ist, das seinerseits mit einer Mengensteuereinheit in der Äthanolzuleitung und/oder der Kohlendioxidzuleitung verbunden ist.A carburizing plant according to the invention is characterized in that the associated carburizing furnace for the purpose of atmosphere formation only an ethanol source (A) and a carbon dioxide source (C) served and therefore with this is connected, and that a measuring device (M) for measuring the carbon level is present in the furnace, which in turn has a quantity control unit in the ethanol feed line and / or the carbon dioxide feed line is connected.
Im folgenden wird die Erfindung in Verbindung mit der anliegenden Figur anhand eines Ausführungsbeispiels näher erläutert. Die Figur zeigt eine Anlagengestaltung gemäß der Erfindung mit geregelter CO2-Zuführung.The invention is explained in more detail below in connection with the attached figure using an exemplary embodiment. The figure shows a system design according to the invention with regulated CO 2 supply.
Ein Aufkohlungsofen O ist zunächst mit einer Äthanolquelle A und mit einer Kohlendioxidquelle
C über geeignete Leitungen und Stellglieder zu koppeln. Im gezeigten
Fall besteht die Äthanolversorgung aus einer Äthanolpumpe P und einer Leitung 1,
die vor Erreichen des Aufkohlungsofens in eine Verdüsungseinheit V einmündet.
Ebenso in die Verdüsungseinheit mündet eine Kohlendioxidzuleitung 2d. Die Kohlendioxidzuleitung
2d teilt sich stromaufwärts der Verdüsungseinheit V in einen Parallelschaltungsabschnitt
mit zwei Leitungen 2b und 2c auf, in denen jeweils ein Stellglied -
S1 und S2 - zur Mengenregelung vorhanden ist. Schließlich ist die Parallelschaltung
über einen Leitungsabschnitt 2a und ein Hauptventil H mit der CO2-Quelle C verbunden.
Ferner ist ein Flußmengenmesser FIC im Leitungsabschnitt 2a vorhanden. Darüber
hinaus ist der Aufkohlungsofen O mit einem Meßgerät M zur Messung des Kohlenstoffpegels
in seinem Innenraum ausgestattet. Das Meßgerät M wiederum ist mit
einem Steuergerät S verbunden, das seinerseits auf das Stellglied S2 in der Bypassleitung
2c der Parallelschaltung einwirkt.A carburizing furnace O is first to be coupled to an ethanol source A and to a carbon dioxide source C via suitable lines and actuators. In the case shown, the ethanol supply consists of an ethanol pump P and a
Eine erfindungsgemäße Verfahrensweise dieser Anlage besteht darin, daß in den auf Temperatur befindlichen Ofen O die Ausgangsmedien Äthanol und Kohlendioxid in bestimmten Basisquantitäten eingeleitet werden, die durch geeignete Einstellung der Pumpleistung der Äthanolpumpe P sowie des Stellglieds S1 festgelegt werden. Grundsätzlich sind die Zuleitungsmengen etwa so einzustellen, daß ein Mol Äthanol auf ein Mol CO2 kommt, wobei in der gezeigten Variante grundsätzlich ein Äthanolüberschuß vorzusehen ist. Im Ofen bei über 800°C entsteht aus diesen Ausgangsmedien eine, im wesentlichen im Verhältnis 1:1 CO und H2 enthaltende, Atmosphäre, deren Kohlenstoffpegel durch das Meßgerät M, beispielsweise eine Sauerstoffsonde oder eine C-Strom-Sonde, ermittelt wird. Da im beschriebenen Fall im Grundsatz mit einem Äthanolüberschuß gefahren wird, entsteht ein relativ hoher C-Pegel in der Grundeinstellung der Anlage. Wird daher vom Meßgerät ein den gewünschten C-Pegel übersteigender Wert ermittelt, so wird durch das entsprechend programmierte Steuergerät S das Öffnen des Stellglieds S2 ausgelöst, und damit die CO2-Zufuhr erhöht. In der Folge sinkt der C-Pegel bis, bei Erreichen einer festzulegenden Untergrenze, das Stellglied S2 wieder geschlossen wird. Auf diese Weise wird eine relativ einfache, extrem effiziente, C-Pegel-geregelte Aufkohlungsatmosphäre erhalten.A procedure according to the invention of this system consists in that the starting media ethanol and carbon dioxide are introduced in certain basic quantities into the furnace O which is at a temperature and which are determined by suitable adjustment of the pumping power of the ethanol pump P and of the actuator S1. Basically, the feed quantities are to be set so that one mole of ethanol comes to one mole of CO 2 , with an excess of ethanol generally being provided in the variant shown. In the furnace at more than 800 ° C, an atmosphere containing essentially 1: 1 CO and H 2 is formed from these starting media, the carbon level of which is determined by the measuring device M, for example an oxygen probe or a C-flow probe. Since in the described case, in principle an excess of ethanol is used, a relatively high C level arises in the basic setting of the system. If a value exceeding the desired C level is therefore determined by the measuring device, the correspondingly programmed control device S triggers the opening of the actuator S2 and thus increases the CO 2 supply. As a result, the C level drops until, when a lower limit to be defined is reached, actuator S2 is closed again. In this way, a relatively simple, extremely efficient, C-level controlled carburizing atmosphere is obtained.
Claims (5)
bei dem die Atmosphäre durch Reaktion eines sauerstoffhaltigen Kohlenwasserstoffmediums, insbesondere eines Alkohols, mit Kohlendioxid gebildet wird, dadurch gekennzeichnet, daß die Atmosphäre speziell auf der Basis von Äthanol und Kohlendioxid gebildet wird und die An- bzw. Abreicherung der Atmosphäre, also die Einstellung eines bestimmten Kohlenstoffpegels, durch entsprechende Verstellung des stöchiometrischen Verhältnisses von Äthanol und Kohlendioxid erzielt wird.Process for carburizing metallic workpieces in a furnace at high temperatures and in an atmosphere containing CO and H 2 ,
in which the atmosphere is formed by reaction of an oxygen-containing hydrocarbon medium, in particular an alcohol, with carbon dioxide, characterized in that the atmosphere is specifically formed on the basis of ethanol and carbon dioxide and the enrichment or depletion of the atmosphere, i.e. the setting of a certain one Carbon level, is achieved by adjusting the stoichiometric ratio of ethanol and carbon dioxide.
daß ein Meßgerät (M) zur Messung des Kohlenstoffpegels im Ofen vorhanden ist, das seinerseits mit einer Mengensteuereinheit in der Äthanolzuleitung und/oder der Kohlendioxidzuleitung verbunden ist.Carburizing plant, characterized in that the associated carburizing furnace uses only an ethanol source (A) and a carbon dioxide source (C) for the purpose of atmospheric formation and is consequently connected to them, and
that a measuring device (M) for measuring the carbon level is present in the furnace, which in turn is connected to a quantity control unit in the ethanol supply line and / or the carbon dioxide supply line.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19819042A DE19819042A1 (en) | 1998-04-28 | 1998-04-28 | Process and plant for gas carburizing |
| DE19819042 | 1998-04-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0953654A1 true EP0953654A1 (en) | 1999-11-03 |
| EP0953654B1 EP0953654B1 (en) | 2003-09-17 |
Family
ID=7866092
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP99108094A Expired - Lifetime EP0953654B1 (en) | 1998-04-28 | 1999-04-23 | Process and apparatus for gas carburising |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0953654B1 (en) |
| AT (1) | ATE250153T1 (en) |
| DE (2) | DE19819042A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2939448A1 (en) * | 2008-12-09 | 2010-06-11 | Air Liquide | PROCESS FOR PRODUCING A GAS ATMOSPHERE FOR PROCESSING METALS |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0040094A1 (en) * | 1980-05-12 | 1981-11-18 | Air Products And Chemicals, Inc. | Carburizing process utilizing atmospheres generated from nitrogen-ethanol based mixtures |
| DE3224607A1 (en) * | 1982-07-01 | 1984-01-05 | Linde Ag, 6200 Wiesbaden | Method for the case-hardening and neutral-carburising annealing of metal workpieces |
| US4950334A (en) * | 1986-08-12 | 1990-08-21 | Mitsubishi Jidosha Kogyo Kabushiki Kaisha | Gas carburizing method and apparatus |
| DE4340060C1 (en) * | 1993-11-24 | 1995-04-20 | Linde Ag | Process for gas carburising |
| EP0859068A1 (en) * | 1997-02-18 | 1998-08-19 | Dowa Mining Co., Ltd. | Method and apparatus for controlling the atmosphere in a heat treatment furnace |
-
1998
- 1998-04-28 DE DE19819042A patent/DE19819042A1/en not_active Withdrawn
-
1999
- 1999-04-23 DE DE59906984T patent/DE59906984D1/en not_active Expired - Fee Related
- 1999-04-23 EP EP99108094A patent/EP0953654B1/en not_active Expired - Lifetime
- 1999-04-23 AT AT99108094T patent/ATE250153T1/en not_active IP Right Cessation
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0040094A1 (en) * | 1980-05-12 | 1981-11-18 | Air Products And Chemicals, Inc. | Carburizing process utilizing atmospheres generated from nitrogen-ethanol based mixtures |
| DE3224607A1 (en) * | 1982-07-01 | 1984-01-05 | Linde Ag, 6200 Wiesbaden | Method for the case-hardening and neutral-carburising annealing of metal workpieces |
| US4950334A (en) * | 1986-08-12 | 1990-08-21 | Mitsubishi Jidosha Kogyo Kabushiki Kaisha | Gas carburizing method and apparatus |
| DE4340060C1 (en) * | 1993-11-24 | 1995-04-20 | Linde Ag | Process for gas carburising |
| EP0859068A1 (en) * | 1997-02-18 | 1998-08-19 | Dowa Mining Co., Ltd. | Method and apparatus for controlling the atmosphere in a heat treatment furnace |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2939448A1 (en) * | 2008-12-09 | 2010-06-11 | Air Liquide | PROCESS FOR PRODUCING A GAS ATMOSPHERE FOR PROCESSING METALS |
| WO2010066979A1 (en) * | 2008-12-09 | 2010-06-17 | L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude | Method for producing a gaseous atmosphere for treating metals |
| US8679264B2 (en) | 2008-12-09 | 2014-03-25 | L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude | Method for producing a gaseous atmosphere for treating metals |
Also Published As
| Publication number | Publication date |
|---|---|
| ATE250153T1 (en) | 2003-10-15 |
| EP0953654B1 (en) | 2003-09-17 |
| DE19819042A1 (en) | 1999-11-04 |
| DE59906984D1 (en) | 2003-10-23 |
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