EP0738785B1 - Process and apparatus for adjusting the carbon monoxide concentration of a furnace atmosphere for carburizing or nitrocarburizing of metallic parts - Google Patents
Process and apparatus for adjusting the carbon monoxide concentration of a furnace atmosphere for carburizing or nitrocarburizing of metallic parts Download PDFInfo
- Publication number
- EP0738785B1 EP0738785B1 EP96101732A EP96101732A EP0738785B1 EP 0738785 B1 EP0738785 B1 EP 0738785B1 EP 96101732 A EP96101732 A EP 96101732A EP 96101732 A EP96101732 A EP 96101732A EP 0738785 B1 EP0738785 B1 EP 0738785B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- content
- furnace
- furnace atmosphere
- atmosphere
- carburizing
- 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
- 238000000034 method Methods 0.000 title claims abstract description 35
- 229910002091 carbon monoxide Inorganic materials 0.000 title claims description 5
- 238000005255 carburizing Methods 0.000 title description 7
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title 1
- 238000005256 carbonitriding Methods 0.000 claims abstract description 9
- 230000001105 regulatory effect Effects 0.000 claims abstract description 7
- 229930195733 hydrocarbon Natural products 0.000 claims abstract description 4
- 150000002430 hydrocarbons Chemical class 0.000 claims abstract description 4
- 239000004215 Carbon black (E152) Substances 0.000 claims abstract description 3
- 239000000203 mixture Substances 0.000 claims abstract description 3
- 239000002184 metal Substances 0.000 claims abstract 2
- 229910052751 metal Inorganic materials 0.000 claims abstract 2
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 24
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 11
- 239000000126 substance Substances 0.000 claims description 8
- 229910021529 ammonia Inorganic materials 0.000 claims description 5
- 239000000446 fuel Substances 0.000 claims description 5
- 239000007800 oxidant agent Substances 0.000 claims description 4
- 230000001590 oxidative effect Effects 0.000 claims description 2
- 229910000069 nitrogen hydride Inorganic materials 0.000 claims 1
- 239000000463 material Substances 0.000 abstract 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 6
- 239000004071 soot Substances 0.000 description 6
- 239000007789 gas Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000005755 formation reaction Methods 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000001681 protective effect Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000003958 fumigation Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000003345 natural gas Substances 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 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
- C23C8/22—Carburising of ferrous surfaces
Definitions
- the invention relates to a method for controlling the CO content of a furnace atmosphere for carburizing and carbonitriding metallic workpieces in a furnace, the furnace atmosphere by directly feeding a mixture of an oxidizing agent, eg. B. air, and a hydrocarbon-containing fuel and optionally ammonia (NH 3 ) generated in the furnace, the CO content of the furnace atmosphere is determined and compared with a freely definable value for the CO content.
- an oxidizing agent eg. B. air
- NH 3 optionally ammonia
- the invention further relates to an apparatus for performing this method.
- the required carburizing atmosphere is generated either in separate inert gas generators (endogas) or by feeding nitrogen with methanol into the furnace.
- the furnace has a relatively stable CO value, which in the first case results from the setting of the protective gas generator and the fuel used in the protective gas generator, and in the second case from the percentage of methanol fed into the furnace.
- a third variant is direct gassing with hydrocarbons and an oxidizing gas component, such as. B. air or CO 2 .
- liquid or gaseous fuels are mixed with the oxidizing agent and fed into the furnace.
- the CO content required for the carburization is generated in the furnace by direct reaction of the fuel with the oxygen of the oxidizing agent.
- natural gas-air fumigation is currently the most widespread. This is due to the high availability and low price of natural gas.
- JP-A-57 177 969 describes a method for regulating the carbon potential the furnace atmosphere is known, in which the determination of the Carbon potential via the determination of the oxygen partial pressure and the determination of the CO partial pressure.
- carbon potential can be obtained from a Enrichment gas can be added to the furnace atmosphere in a separate tank. The dependence of the soot formation on the CO content of the furnace atmosphere is not to be inferred from this publication.
- the invention has for its object to provide a control for the CO content of the furnace atmosphere, the continuous operation without sooting in carburizing and carbonitriding furnaces even at low carburizing temperatures ( ⁇ 870 ° C) and also in the presence of ammonia (carbonitriding) Furnace chamber guaranteed.
- the task of continuous and trouble-free operation with a regulated CO content is achieved in that when a freely adjustable minimum CO content is reached, methanol or CO 2 is added to the furnace atmosphere as a CO-forming substance.
- the methanol fed into the furnace atmosphere becomes after the reaction CH 3 OH ⁇ CO + 2H 2 split (at furnace temperatures ⁇ 800 ° C), whereby the CO content in the furnace atmosphere rises again above the set minimum CO content.
- An alternative CO-forming substance is CO 2 .
- a CO content of around 12% has been found to be the minimum CO content in the furnace atmosphere emphasized that falling below this value is a strong one Soot formation and, moreover, the furnace atmosphere no longer is precisely controllable.
- As a range for the minimum and the upper CO content there is a range between about 12% and 15% CO in the furnace atmosphere proven to be particularly suitable. Because below a CO content of 15%, the course of the CO decrease is very flat, an increase is sufficient of the CO content by adding the CO generator up to this limit of about 15% off the process for a long time with a CO content above to drive the minimum limit. In addition, this narrow range has As a result, only a little CO generator is used to increase the CO content must be kept, which in turn keeps the cost of the process low can be.
- the device for performing the described method has one Furnace chamber and a CO analyzer arranged in the furnace chamber for Determine the CO content in the furnace atmosphere and one programmable CO controller to - depending on the CO content in the Furnace atmosphere - a valve and a pump for feeding to control a CO-forming substance stored in a tank.
- the valve and the pump will stop when the set minimum is reached CO content switched to passage or operation. When the set one is reached The upper limit of the CO content is closed again and the pump turned off.
- the diagram in FIG. 1 shows the course of the CO content during a carbonitriding process.
- the CO content drops sharply in the course of the process.
- the curve of the CO content curve runs very flat below 15% CO.
- Below the 12% line shown as the minimum CO content limit the too low CO content in the furnace atmosphere causes the furnace to soot quickly.
- the furnace atmosphere becomes a CO-forming substance, e.g. B. added methanol, which due to the high process temperature after the reaction CH 3 OH ⁇ CO + 2H 2 is split. Due to this CO formation due to the splitting of methanol, the CO content in the furnace atmosphere rises very quickly, which is illustrated by the steep rise in the CO curve in FIG. 1.
- a freely adjustable upper limit is reached - 15% in FIG. 1 - the methanol supply is switched off again, so that the CO content in the furnace atmosphere decreases again as a result of the continuously ongoing process.
- Fig. 2 is the structure of a device for performing the method described above.
- a CO analyzer 1 the CO content of the furnace atmosphere in a furnace chamber 2 is determined.
- the control unit also has a programmable CO controller 3, which freely adjustable values for the upper and lower CO content entered can be.
- the CO controller 3 activates via the control path shown in dashed lines Valve 4 and a pump 5 as soon as a comparison of the CO analyzer 1 determined CO content with the entered in the CO controller 3 minimal CO content has shown that this reaches the minimum CO content has been.
- the pump 5 controlled by the CO controller 3 then conveys the CO generator from a tank 6 through the passage valve 4 in the Furnace chamber 2.
- the CO generator is as above described split, causing the CO content in the furnace atmosphere again increases. If the continuous adjustment of the determined by the CO analyzer 1 CO content in the furnace atmosphere with those stored in the CO controller 3 Values indicate that the entered upper CO content is reached has been, the valve 4 are closed via the CO controller 3 and the pump 5 turned off again.
Landscapes
- 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)
- Furnace Details (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren zur Regelung des CO-Gehaltes einer Ofenatmosphäre zum Aufkohlen und Carbonitrieren metallischer Werkstücke in einem Ofen, wobei die Ofenatmosphäre durch direkte Einspeisung eines Gemisches aus einem Oxidationsmittel, z. B. Luft, und einem kohlenwasserstoffhaltigen Brennstoff sowie gegebenenfalls Ammoniak (NH3) in dem Ofen erzeugt wird der CO-Gehalt der Ofenatmosphäre bestimmt und mit einem frei vorgebbaren Wert für den CO-Gehalt verglichen wird.The invention relates to a method for controlling the CO content of a furnace atmosphere for carburizing and carbonitriding metallic workpieces in a furnace, the furnace atmosphere by directly feeding a mixture of an oxidizing agent, eg. B. air, and a hydrocarbon-containing fuel and optionally ammonia (NH 3 ) generated in the furnace, the CO content of the furnace atmosphere is determined and compared with a freely definable value for the CO content.
Die Erfindung betrifft ferner eine Vorrichtung zur Durchführung dieses Verfahrens.The invention further relates to an apparatus for performing this method.
Bei den Aufkohlungs- oder Carbonitrierverfahren wird die benötigte aufkohlende Atmosphäre entweder in separaten Schutzgasgeneratoren (Endogas) oder durch die Einspeisung von Stickstoff mit Methanol in den Ofen erzeugt. Bei beiden Verfahren der Schutzgaserzeugung ergibt sich im Ofen ein relativ stabiler CO-Wert, der sich im ersten Fall durch die Einstellung des Schutzgasgenerators und dem verwendeten Brennstoff des Schutzgasgenerators und im zweiten Fall durch den prozentualen Anteil an in den Ofen eingespeistem Methanol ergibt. Eine dritte Variante ist die Direktbegasung mit Kohlenwasserstoffen und einem oxydierenden Gasbestandteil, wie z. B. Luft oder CO2. Bei dieser Technik werden flüssige oder gasförmige Brennstoffe mit dem Oxidationsmittel gemischt und in den Ofen geleitet. Hierbei wird der für die Aufkohlung benötigte CO-Anteil im Ofen durch direkte Reaktion des Brennstoffes mit dem Sauerstoff des Oxidationsmittels erzeugt. Von diesen Direktbegasungsverfahren besitzt die Erdgas-Luft-Begasung zur Zeit die größte Verbreitung. Dies hängt mit der hohen Verfügbarkeit und dem günstigen Preis von Erdgas zusammen.In the carburizing or carbonitriding processes, the required carburizing atmosphere is generated either in separate inert gas generators (endogas) or by feeding nitrogen with methanol into the furnace. In both methods of protective gas production, the furnace has a relatively stable CO value, which in the first case results from the setting of the protective gas generator and the fuel used in the protective gas generator, and in the second case from the percentage of methanol fed into the furnace. A third variant is direct gassing with hydrocarbons and an oxidizing gas component, such as. B. air or CO 2 . With this technique, liquid or gaseous fuels are mixed with the oxidizing agent and fed into the furnace. The CO content required for the carburization is generated in the furnace by direct reaction of the fuel with the oxygen of the oxidizing agent. Of these direct fumigation methods, natural gas-air fumigation is currently the most widespread. This is due to the high availability and low price of natural gas.
Die Umsetzung des Erdgases im Ofen mit dem Luftsauerstoff findet hierbei
gemäß der Gleichung
Beim vollständigen Umsatz des Methans im Ofen mit dem Luftsauerstoff ergibt sich somit ein maximaler CO-Gehalt in der Ofenatmosphäre von 20,5 Vol.-%. Dieser hohe CO-Anteil wird nur unter idealen Bedingungen (sehr hohe Ofentemperatur) erreicht.When the methane is completely converted in the furnace with the atmospheric oxygen there is thus a maximum CO content in the furnace atmosphere of 20.5% by volume. This high CO content is only achieved under ideal conditions (very high furnace temperature) reached.
Bei niedrigen Ofentemperaturen, insbesondere unterhalb von ca. 870°C ist die oben angegebene Reaktion sehr langsam und der Umsatz des Methans in CO entsprechend gering.At low furnace temperatures, especially below approx. 870 ° C, the Reaction given above very slowly and the conversion of methane into CO accordingly low.
Außerdem wird die oben angeführte CO-Bildungsreaktion noch durch die Anwesenheit von Ammoniak (nötig für das Carbonitrieren) behindert.In addition, the above-mentioned CO formation reaction is still caused by the presence hindered by ammonia (necessary for carbonitriding).
Geringe CO-Gehalte bewirken, daß die Kohlenstoffübertragung abnimmt und die Ofenatmosphäre für die Aufkohlung bzw. das Carbonitrieren kaum noch zu regeln ist und der Ofen außerdem sehr schnell verrußt. Das Verrußen des Ofens hat wiederum Produktionsstillstände zur Folge, da zur Beseitigung der Verrußungen der Ofen stillgelegt und ausgebrannt werden muß.Low CO levels cause the carbon transfer to decrease and the furnace atmosphere for carburizing or carbonitriding hardly increases is regulated and the stove also soot very quickly. The sooting of the The furnace in turn results in production downtimes because the removal of the Soot must be shut down and burned out.
Aus der JP-A-57 177 969 ist ein Verfahren zur Regelung des Kohlenstoff-Potentials der Ofenatmosphäre bekannt, bei dem die Bestimmung des Kohlenstoff-Potentials über die Bestimmung des Sauerstoff-Partialdruckes sowie die Bestimmung des CO-Partialdruckes erfolgt. Zur Regelung des Kohlenstoff-Potentials kann bei diesem bekannten Verfahren aus einem separaten Tank ein Anreicherungsgas der Ofenatmosphäre zugegeben werden. Die Abhängigkeit der Rußbildung vom CO-Gehalt der Ofenatmosphäre ist dieser Druckschrift nicht zu entnehmen.JP-A-57 177 969 describes a method for regulating the carbon potential the furnace atmosphere is known, in which the determination of the Carbon potential via the determination of the oxygen partial pressure and the determination of the CO partial pressure. To regulate the In this known method, carbon potential can be obtained from a Enrichment gas can be added to the furnace atmosphere in a separate tank. The dependence of the soot formation on the CO content of the furnace atmosphere is not to be inferred from this publication.
Der Erfindung liegt die Aufgabe zugrunde, eine Regelung für den CO-Gehalt der Ofenatmosphäre zu schaffen, die bei Aufkohlungs- und Carbonitrieröfen auch bei niedrigen Aufkohlungstemperaturen (≤ 870°C) und auch bei Vorhandensein von Ammoniak (Carbonitrieren) einen kontinuierlichen Betrieb ohne Verrußung der Ofenkammer gewährleistet.The invention has for its object to provide a control for the CO content of the furnace atmosphere, the continuous operation without sooting in carburizing and carbonitriding furnaces even at low carburizing temperatures (≤ 870 ° C) and also in the presence of ammonia (carbonitriding) Furnace chamber guaranteed.
Die Aufgabe des kontinuierlichen und störungsfreien Betriebes bei einem geregelten CO-Gehalt wird dadurch gelöst, daß bei Erreichen eines frei einstellbaren minimalen CO-Gehaltes der Ofenatmosphäre als CO-bildender Stoff Methanol oder CO2 zugeführt wird.The task of continuous and trouble-free operation with a regulated CO content is achieved in that when a freely adjustable minimum CO content is reached, methanol or CO 2 is added to the furnace atmosphere as a CO-forming substance.
Das in die Ofenatmosphäre eingespeiste Methanol wird nach der Reaktion
Ein alternativer CO bildender Stoff ist CO2.An alternative CO-forming substance is CO 2 .
Um die jeweils zuzugebende Menge des CO bildenden Stoffs gering und das Verfahren kostengünstig zu halten, kann zusätzlich ein oberer Wert für den CO-Gehalt eingestellt werden, bei dessen Erreichen die Zugabe des CO-Bildners wieder abgestellt wird, bis der CO-Gehalt im Laufe des Verfahrens wieder auf den minimalen CO-Gehalt abgesunken ist.In order to reduce the amount of CO-forming substance to be added and that Keeping the process inexpensive can also be a top value for the CO content can be set, when reached the addition of the CO generator is turned off again until the CO content returns during the process has dropped to the minimum CO content.
Ein CO-Gehalt von etwa 12 % hat sich als minimaler CO-Gehalt in der Ofenatmosphäre herausgestellt, da ein Unterschreiten dieses Wertes eine starke Rußbildung zur Folge hat und darüber hinaus die Ofenatmosphäre nicht mehr exakt regelbar ist. Als Bandbreite für den minimalen und den oberen CO-Gehalt hat sich eine Bandbreite zwischen etwa 12 % und 15 % CO in der Ofenatmosphäre als besonders geeignet erwiesen. Da unterhalb eines CO-Gehaltes von 15 % der Verlauf der CO-Abnahme sehr flach verläuft, reicht ein Anheben des CO-Gehaltes durch die Zugabe des CO-Bildners bis zu dieser Grenze von etwa 15 % aus, um den Prozeß für längere Zeit mit einem CO-Gehalt oberhalb der Minimalgrenze zu fahren. Darüber hinaus hat diese enge Bandbreite zur Folge, daß nur wenig CO-Bildner zum Anheben des CO-Gehaltes verwendet werden muß, wodurch wiederum die Kosten des Verfahrens niedrig gehalten werden können.A CO content of around 12% has been found to be the minimum CO content in the furnace atmosphere emphasized that falling below this value is a strong one Soot formation and, moreover, the furnace atmosphere no longer is precisely controllable. As a range for the minimum and the upper CO content there is a range between about 12% and 15% CO in the furnace atmosphere proven to be particularly suitable. Because below a CO content of 15%, the course of the CO decrease is very flat, an increase is sufficient of the CO content by adding the CO generator up to this limit of about 15% off the process for a long time with a CO content above to drive the minimum limit. In addition, this narrow range has As a result, only a little CO generator is used to increase the CO content must be kept, which in turn keeps the cost of the process low can be.
Die Vorrichtung zur Durchführung des beschriebenen Verfahrens weist eine Ofenkammer und einen in der Ofenkammer angeordneten CO-Analysator zum Bestimmen des CO-Gehaltes in der Ofenatmosphäre sowie einen programmierbaren CO-Regler auf, um - in Abhängigkeit des CO-Gehaltes in der Ofenatmosphäre - ein Ventil sowie eine Pumpe zum Zuführen eines in einem Tank bevorrateten CO-bildenden Stoffes anzusteuern. Das Ventil und die Pumpe werden bei Erreichen des eingestellten minimalen CO-Gehaltes auf Durchlaß bzw. Betrieb geschaltet. Bei Erreichen der eingestellten oberen Grenze des CO-Gehaltes wird das Ventil wieder geschlossen und die Pumpe abgeschaltet.The device for performing the described method has one Furnace chamber and a CO analyzer arranged in the furnace chamber for Determine the CO content in the furnace atmosphere and one programmable CO controller to - depending on the CO content in the Furnace atmosphere - a valve and a pump for feeding to control a CO-forming substance stored in a tank. The valve and the pump will stop when the set minimum is reached CO content switched to passage or operation. When the set one is reached The upper limit of the CO content is closed again and the pump turned off.
Weitere Einzelheiten und Vorteile ergeben sich aus der nachfolgenden Beschreibung der zugehörigen Zeichnungen, in denen das erfindungsgemäße Verfahren sowie eine Vorrichtung zur Durchführung dieses Verfahrens schematisch dargestellt ist. In den Zeichnungen zeigen:
- Fig. 1
- ein Diagramm über den Verlauf des CO-Gehaltes in der Ofenatmosphäre bei dem erfindungsgemäßen Verfahren und
- Fig. 2
- eine schematische Darstellung einer Vorrichtung zur Durchführung des erfindungsgemäßen Verfahrens.
- Fig. 1
- a diagram of the course of the CO content in the furnace atmosphere in the inventive method and
- Fig. 2
- is a schematic representation of an apparatus for performing the method according to the invention.
In dem in Fig. 1 dargestellten Diagramm ist der Verlauf des CO-Gehaltes während
eines Carbonitrierverfahrens dargestellt. Durch die Zugabe von Ammoniak
zur Ofenatmosphäre sinkt der CO-Gehalt im Verlauf des Prozesses
stark ab. Wie aus Fig. 1 ersichtlich, verläuft die Kurve des CO-Gehalt-Verlaufes
unterhalb von 15 % CO sehr flach. Unterhalb der als minimale CO-Gehalt-Grenze
dargestellten 12 %-Linie verursacht der zu geringe CO-Gehalt in der
Ofenatmosphäre ein schnelles Verrußen des Ofens. Beim Erreichen dieser unteren
Grenze wird der Ofenatmosphäre ein CO bildender Stoff, z. B. Methanol
zugegeben, welches infolge der hohen Prozeßtemperatur nach der Reaktion
Aus Fig. 1 ist ersichtlich, daß schon das geringfügige Anheben des CO-Gehaltes von 12 % auf 15 % für einen längeren Zeitraum einen störungsfreien Ablauf des Prozesses oberhalb der Rußgrenze ermöglicht, da der Verlauf der CO-Kurve unterhalb von 15 % sehr flach ist.From Fig. 1 it can be seen that even the slight increase in the CO content a trouble-free process from 12% to 15% for a longer period of the process above the soot limit, because the course of the CO curve below 15% is very flat.
In Fig. 2 ist schematisch der Aufbau einer Vorrichtung zur Durchführung des
voranstehend beschriebenen Verfahrens dargestellt. Mittels eines CO-Analysators
1 wird der CO-Gehalt der Ofenatmosphäre in einer Ofenkammer 2 ermittelt.
Die Regeleinheit weist ferner einen programmierbaren CO-Regler 3 auf,
welchem frei einstellbare Werte für den oberen und unteren CO-Gehalt eingegeben
werden können.In Fig. 2 is the structure of a device for performing the
method described above. Using a
Über die gestrichelt dargestellte Regelstrecke steuert der CO-Regler 3 ein
Ventil 4 und eine Pumpe 5 an, sobald ein Abgleich des vom
CO-Analysator 1 ermittelten CO-Gehaltes mit dem im CO-Regler 3 eingegebenen
minimalen CO-Gehalt ergeben hat, daß dieser minimale CO-Gehalt erreicht
worden ist.The
Die von dem CO-Regler 3 angesteuerte Pumpe 5 fördert daraufhin den CO-Bildner
aus einem Tank 6 durch das auf Durchlaß geschaltete Ventil 4 in die
Ofenkammer 2. In der Ofenkammer 2 wird der CO-Bildner wie voranstehend
beschrieben gespalten, wodurch der CO-Gehalt in der Ofenatmosphäre wieder
ansteigt. Wenn der fortlaufende Abgleich des von dem CO-Analysator 1 ermittelten
CO-Gehaltes in der Ofenatmosphäre mit den in dem CO-Regler 3 gespeicherten
Werten ergibt, daß der eingegebene obere CO-Gehalt erreicht
worden ist, werden über den CO-Regler 3 das Ventil 4 geschlossen und
die Pumpe 5 wieder abgestellt.The
Der voranstehend beschriebene Prozeß beginnt von neuem, sobald CO-Analysator
1 und CO-Regler 3 ein erneutes Erreichen des eingestellten minimalen
CO-Gehaltes ermitteln.The process described above begins again as soon as the
Mit einem solchermaßen geregelten Verfahren wird einerseits gewährleistet, daß der CO-Gehalt der Ofenatmosphäre niemals unter den eingestellten, eine starke Verrußung des Ofens bewirkenden minimalen CO-Gehalt absinkt und andererseits nur soviel CO-Bildner der Ofenatmosphäre zugeführt wird, wie dies für einen kostengünstigen und störungsfreien Betrieb des Verfahrens notwendig ist. With such a regulated process, on the one hand, it is guaranteed that the CO content of the furnace atmosphere is never below the set one strong sooting of the furnace causes minimal CO content and decreases on the other hand, only as much CO former is added to the furnace atmosphere as this for an inexpensive and trouble-free operation of the method necessary is.
- 11
- CO-AnalysatorCO analyzer
- 22nd
- OfenkammerFurnace chamber
- 33rd
- CO-ReglerCO regulator
- 44th
- VentilValve
- 55
- Pumpepump
- 66
- Tanktank
Claims (5)
- Method for regulating the CO content of a furnace atmosphere for carburising and carbonitriding metal workpieces in a furnace, wherein the furnace atmosphere is produced by direct supply to the furnace of a mixture of an oxidant, e.g. air, and a hydrocarbon-containing fuel as well as if necessary ammonia (NH3), and the CO content of the furnace atmosphere is determined and compared with a freely presettable value for the CO content, characterised in that, on reaching a freely adjustable minimum CO content of the furnace atmosphere, methanol or CO2 is supplied as the CO-forming substance.
- Method according to claim 1, characterised in that the furnace atmosphere is supplied with the CO-forming substance until a freely adjustable upper CO content is achieved.
- Method according to claim 1 or 2, characterised in that the minimum CO content is about 12% CO.
- Method according to claim 2, characterised in that the regulated bandwidth of CO content is between about 12% and about 15% CO.
- Apparatus for carrying out the method according to any of claims 1 to 4 with a furnace chamber (2) and a CO analyser (1) arranged in the furnace chamber (2) for determining the CO content in the furnace atmosphere, characterised by a programmable CO regulator (3) for driving a valve (4) as well as a pump (5) for supplying a CO-forming substance starting from a tank (6) as a function of the CO content in the furnace atmosphere
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19514932A DE19514932A1 (en) | 1995-04-22 | 1995-04-22 | Method and device for regulating the CO content of an oven atmosphere for carburizing and carbonitriding metallic workpieces |
| DE19514932 | 1995-04-22 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0738785A1 EP0738785A1 (en) | 1996-10-23 |
| EP0738785B1 true EP0738785B1 (en) | 1999-03-31 |
Family
ID=7760177
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP96101732A Expired - Lifetime EP0738785B1 (en) | 1995-04-22 | 1996-02-07 | Process and apparatus for adjusting the carbon monoxide concentration of a furnace atmosphere for carburizing or nitrocarburizing of metallic parts |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US5741371A (en) |
| EP (1) | EP0738785B1 (en) |
| JP (1) | JPH08296028A (en) |
| CN (1) | CN1136330C (en) |
| AT (1) | ATE178366T1 (en) |
| CA (1) | CA2174409C (en) |
| DE (2) | DE19514932A1 (en) |
| ES (1) | ES2129897T3 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3409236B2 (en) * | 1997-02-18 | 2003-05-26 | 同和鉱業株式会社 | Atmosphere control method of heat treatment furnace |
| DE19940370C2 (en) * | 1999-08-25 | 2001-07-12 | Messer Griesheim Gmbh | Process for nitrocarburizing metallic workpieces |
| US6635121B2 (en) * | 2000-02-04 | 2003-10-21 | American Air Liquide, Inc. | Method and apparatus for controlling the decarburization of steel components in a furnace |
| JP3884326B2 (en) * | 2002-05-22 | 2007-02-21 | 大陽日酸株式会社 | Carburizing atmosphere gas generator and method |
| EP2360287B1 (en) * | 2005-12-08 | 2013-08-07 | NTN Corporation | Method of gas carbonitriding, process for producing machine part and machine part |
| CN103589987B (en) * | 2013-12-06 | 2016-01-20 | 龙工（上海）精工液压有限公司 | A kind of thermal treatment process of ram pump transmission shaft |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH628092A5 (en) * | 1978-03-21 | 1982-02-15 | Ipsen Ind Int Gmbh | METHOD AND DEVICE FOR REGULATING THE CARBON LEVEL OF A CHEMICALLY REACTIVE GAS MIXTURE. |
| GB2044804A (en) * | 1979-03-16 | 1980-10-22 | Boc Ltd | Heat treatment method |
| JPS57177969A (en) * | 1981-04-23 | 1982-11-01 | Chugai Ro Kogyo Kaisha Ltd | Controlling method for carbon potential in furnace |
| US5133813A (en) * | 1990-07-03 | 1992-07-28 | Tokyo Heat Treating Company Ltd. | Gas-carburizing process and apparatus |
-
1995
- 1995-04-22 DE DE19514932A patent/DE19514932A1/en not_active Withdrawn
-
1996
- 1996-02-07 DE DE59601530T patent/DE59601530D1/en not_active Expired - Lifetime
- 1996-02-07 ES ES96101732T patent/ES2129897T3/en not_active Expired - Lifetime
- 1996-02-07 EP EP96101732A patent/EP0738785B1/en not_active Expired - Lifetime
- 1996-02-07 AT AT96101732T patent/ATE178366T1/en active
- 1996-04-04 JP JP8108500A patent/JPH08296028A/en active Pending
- 1996-04-11 CN CNB961045396A patent/CN1136330C/en not_active Expired - Fee Related
- 1996-04-17 CA CA002174409A patent/CA2174409C/en not_active Expired - Fee Related
- 1996-04-22 US US08/637,328 patent/US5741371A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08296028A (en) | 1996-11-12 |
| CA2174409A1 (en) | 1996-10-23 |
| US5741371A (en) | 1998-04-21 |
| CN1136330C (en) | 2004-01-28 |
| ES2129897T3 (en) | 1999-06-16 |
| CA2174409C (en) | 2009-06-23 |
| DE59601530D1 (en) | 1999-05-06 |
| ATE178366T1 (en) | 1999-04-15 |
| CN1136597A (en) | 1996-11-27 |
| DE19514932A1 (en) | 1996-10-24 |
| EP0738785A1 (en) | 1996-10-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0049530B1 (en) | Method and device for carbonizing metallic pieces | |
| DE2450879A1 (en) | METHOD FOR HEAT TREATMENT OF FERROUS METALS | |
| EP2302081B1 (en) | Method and device for preparing process gases for the thermal treatment of metallic materials/workpieces in industrial ovens | |
| DE102008029001B3 (en) | Method and device for the heat treatment of metallic materials | |
| EP0738785B1 (en) | Process and apparatus for adjusting the carbon monoxide concentration of a furnace atmosphere for carburizing or nitrocarburizing of metallic parts | |
| DE4212307C2 (en) | Process for the production of a protective or reaction gas for the heat treatment of metals | |
| DE4400391A1 (en) | Process to avoid edge oxidation when carburizing steels | |
| EP2878684A2 (en) | Method for controlling the decarbonisation potential of a metal melt containing carbon during an oxygen/inert gas blowing and vacuum treatment | |
| EP0031034B1 (en) | Process for the adjustable carburizing or heating in a protective gas of steel work pieces | |
| EP2627795A1 (en) | Method and arrangement for carburizing and carbonitriding metallic materials | |
| DE3149212A1 (en) | METHOD FOR ADJUSTING OVEN ATMOSPHERES | |
| DE3406792A1 (en) | METHOD AND DEVICE FOR GLOWING METAL PARTS | |
| DE2408984C3 (en) | Process for producing defined nitriding layers on iron and iron alloys in an oxygen-containing gas atmosphere and arrangement for producing and keeping constant the starting gas mixtures required for this | |
| DE19610722B4 (en) | Process for the preparation of protective or reaction gases for the heat treatment of metals | |
| DE19651878C2 (en) | Process for the production of a protective or reaction gas for the heat treatment of metals | |
| EP4065889B1 (en) | Combustion of the co in secondary metallurgical exhaust gas, with calorific value control and volume flow control | |
| DE10221605A1 (en) | Method and device for the heat treatment of metallic workpieces | |
| DE3534104C2 (en) | ||
| EP1673483A1 (en) | Method for heat-treating iron-containing materials | |
| DE3228892A1 (en) | METHOD AND DEVICE FOR CARBONING | |
| DE3224607A1 (en) | Method for the case-hardening and neutral-carburising annealing of metal workpieces | |
| EP1456422B1 (en) | Method for avoiding adhesions and scratches during recrystallization annealing of cold rolled strips | |
| DE3002463A1 (en) | Nitriding of steel in stream of ammonia gas - where control of ammonia concn. in gas mixt. leaving nitriding container ensures min. consumption of ammonia | |
| DE280966C (en) | ||
| DE19509614A1 (en) | Controlling nitriding value of nitriding and nitrocarburisation atmos |
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 CH DE ES FR GB IT LI |
|
| 17P | Request for examination filed |
Effective date: 19960907 |
|
| RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: IPSEN INTERNATIONAL GMBH |
|
| 17Q | First examination report despatched |
Effective date: 19970611 |
|
| GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
| GRAG | Despatch of communication of intention to grant |
Free format text: ORIGINAL CODE: EPIDOS AGRA |
|
| GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
| GRAH | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOS IGRA |
|
| GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
| AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT CH DE ES FR GB IT LI |
|
| REF | Corresponds to: |
Ref document number: 178366 Country of ref document: AT Date of ref document: 19990415 Kind code of ref document: T |
|
| REG | Reference to a national code |
Ref country code: CH Ref legal event code: EP |
|
| REG | Reference to a national code |
Ref country code: CH Ref legal event code: NV Representative=s name: E. BLUM & CO. PATENTANWAELTE |
|
| ET | Fr: translation filed | ||
| REF | Corresponds to: |
Ref document number: 59601530 Country of ref document: DE Date of ref document: 19990506 |
|
| GBT | Gb: translation of ep patent filed (gb section 77(6)(a)/1977) |
Effective date: 19990416 |
|
| ITF | It: translation for a ep patent filed | ||
| REG | Reference to a national code |
Ref country code: ES Ref legal event code: FG2A Ref document number: 2129897 Country of ref document: ES Kind code of ref document: T3 |
|
| 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 | ||
| REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
| REG | Reference to a national code |
Ref country code: CH Ref legal event code: PFA Owner name: IPSEN INTERNATIONAL GMBH Free format text: IPSEN INTERNATIONAL GMBH#FLUTSTRASSE 78#47533 KLEVE (DE) -TRANSFER TO- IPSEN INTERNATIONAL GMBH#FLUTSTRASSE 78#47533 KLEVE (DE) |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: CH Payment date: 20140218 Year of fee payment: 19 Ref country code: DE Payment date: 20140219 Year of fee payment: 19 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: AT Payment date: 20140212 Year of fee payment: 19 Ref country code: IT Payment date: 20140227 Year of fee payment: 19 Ref country code: FR Payment date: 20140219 Year of fee payment: 19 Ref country code: ES Payment date: 20140226 Year of fee payment: 19 |
|
| PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20140218 Year of fee payment: 19 |
|
| REG | Reference to a national code |
Ref country code: DE Ref legal event code: R119 Ref document number: 59601530 Country of ref document: DE |
|
| REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
| REG | Reference to a national code |
Ref country code: AT Ref legal event code: MM01 Ref document number: 178366 Country of ref document: AT Kind code of ref document: T Effective date: 20150207 |
|
| GBPC | Gb: european patent ceased through non-payment of renewal fee |
Effective date: 20150207 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: CH Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150228 Ref country code: LI Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150228 |
|
| REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST Effective date: 20151030 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: AT Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150207 |
|
| 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: 20150207 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150207 Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150901 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150302 |
|
| REG | Reference to a national code |
Ref country code: ES Ref legal event code: FD2A Effective date: 20160329 |
|
| PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: ES Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20150208 |