WO2001014611A1 - Method for nitro-carburization of metal workpieces - Google Patents

Method for nitro-carburization of metal workpieces Download PDF

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Publication number
WO2001014611A1
WO2001014611A1 PCT/EP2000/007576 EP0007576W WO0114611A1 WO 2001014611 A1 WO2001014611 A1 WO 2001014611A1 EP 0007576 W EP0007576 W EP 0007576W WO 0114611 A1 WO0114611 A1 WO 0114611A1
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treatment
gas
carbon
temperature
carbon dioxide
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PCT/EP2000/007576
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German (de)
French (fr)
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Hans-Peter Schmidt
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Messer Griesheim Gmbh
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Priority to AT00962293T priority Critical patent/ATE257865T1/en
Priority to DE50005043T priority patent/DE50005043D1/en
Priority to EP00962293A priority patent/EP1230415B1/en
Priority to PL00353217A priority patent/PL195105B1/en
Publication of WO2001014611A1 publication Critical patent/WO2001014611A1/en

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    • 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
    • C23C8/28—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 more than one element being applied in one step
    • C23C8/30—Carbo-nitriding

Definitions

  • the invention relates to a method for nitrocarburizing metallic workpieces by treating the workpieces in a treatment atmosphere containing nitrogen, carbon monoxide and hydrogen at a treatment temperature in a treatment room, carbon dioxide being used as the carbon donor to generate the treatment atmosphere.
  • the nitrogen donor is basically ammonia (NH 3 ), while various gas mixtures such as air-hydrocarbon mixtures (endogas and exogas) and carbon dioxide are used as carbon donors. In the nitriding furnace, these gases react with the hydrogen present, with stationary carbon, nitrogen and oxygen activity depending on the thermal and chemical conditions.
  • the atomic nitrogen produced during ammonia splitting reacts particularly easily with the metal to form nitrides when it comes into contact with metal surfaces (hereinafter referred to as (N) a d).
  • Different nitride phases can form in connection with iron.
  • nitride phases in the form of so-called ⁇ -nitride (F ⁇ 2-3N) and ⁇ '-nitride (F ⁇ 4N) or mixtures of these nitrides, for example, are preferred with regard to high hardness and wear resistance.
  • the reactions taking place during the nitride formation of Fe-containing metals can be described schematically using the following chemical equations:
  • the carbon dissolved in the nitride affects morphology, compactness, pore hem and adhesion of the connection layer and its corrosion and Wear resistance.
  • the type and extent of nitride formation is significantly influenced by the carbon activity in the nitriding atmosphere. The carbon activity in turn depends on the one used
  • Carbon donor It drops in the order of propane, endogas, exogas and carbon dioxide. Since the composition of the gas phase in the nitriding furnace thus has a significant influence on the result of the nitrocarburization, it is advantageous if it can be set within as wide a range as possible.
  • the carbon dioxide contents are usually between 4 and 10% by volume.
  • the carbon dioxide is metered directly into the furnace chamber of the nitriding furnace, where it partially reacts with hydrogen according to the following reaction equation:
  • a carbon activity (a c, B ), which is adapted to the prevailing conditions, settles down and can be defined according to the Boudouard reaction:
  • K B denotes the constant of the Boudouard equilibrium.
  • the maximum carbon activity is 1, which corresponds to the activity of pure graphite.
  • K N nitriding index
  • the known method is characterized in that the NH 3 gas throughput is kept constant and only the operating point of the pre-splitter in which the NH 3 split gas is generated is regulated.
  • a high nitriding index requires a high ammonia content in the nitriding furnace, which in turn results in a high residual ammonia content in the furnace exhaust gas, which leaves the furnace unused.
  • Substance such as methanol is fed into the furnace space.
  • the CO-forming components such as methanol or CO 2 are thus fed directly into the treatment room.
  • carburizing or carbonitriding this is effective due to the high temperatures involved, but not at the usual, relatively low nitriding temperatures of max. 580 ° C.
  • methanol does not cleave stoichiometrically, but undesirable cleavage products such as CH 4 and other higher hydrocarbons, CO 2 , aldehydes, ketones, etc. are formed, some of which are toxic and corrosive when condensed.
  • the cleavage of the methanol strongly depends on the conditions in the boiler room and on the surface of the batch, so that the desired furnace gas composition cannot be reproduced. This also has the consequence that soot deposits on the batch material and the boiler room surface due to uncontrolled cracking reactions or undesired carbides are formed.
  • the invention is therefore based on the object of modifying the known method for nitrocarburizing metallic workpieces using carbon dioxide as a carbon donor so that the type and extent of nitride formation can be adjusted within a wide range.
  • a carbon dioxide-containing gas stream is introduced into a reactor upstream of the treatment room and is modified therein by reaction with a hydrogen donor at a reaction temperature above the treatment temperature to give a carbonization gas which has a higher carbon activity than the carbon dioxide-containing gas stream at the treatment temperature.
  • the gas stream containing carbon dioxide is fed to a reactor, modified therein in the direction of a higher carbon activity and then introduced into the treatment room as carbonizing gas.
  • the modification is based on a

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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)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)
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Abstract

The invention relates to a known method for nitro-carburization of metal workpieces, whereby the workpieces are treated in a treatment chamber with a treatment atmosphere containing nitrogen, carbon monoxide and hydrogen at treatment temperature, whereby carbon dioxide is used as carbon contributor to generate the treatment atmosphere. The invention aims at modifying said method so as to be able to regulate as much as possible the type and volume of nitride formation. To this end, a gas flow (1; 21) containing carbon dioxide is introduced into a reactor (4; 24) connected upstream from the treatment chamber (6; 27) and modified therein into a carburizing gas (5; 25) by reaction with a hydrogen contributor (2; 22) at a reaction temperature above treatment temperature, said gas having a higher carbon activity at treatment temperature than the gas flow (1; 21) containing carbon dioxide.

Description

Verfahren für die Nitrocarburierung metallischer WerkstückeProcess for nitrocarburizing metallic workpieces
Die Erfindung betrifft ein Verfahren zum Nitrocarburieren metallischer Werkstücke, indem die Werkstücke in einer Stickstoff, Kohlenmonoxid und Wasserstoff enthaltenden Behandlungsatmosphäre bei einer Behandlungstemperatur in einem Behandlungsraum behandelt werden, wobei zur Erzeugung der Behandlungsatmosphäre Kohlendioxid als Kohlenstoffspender eingesetzt wird.The invention relates to a method for nitrocarburizing metallic workpieces by treating the workpieces in a treatment atmosphere containing nitrogen, carbon monoxide and hydrogen at a treatment temperature in a treatment room, carbon dioxide being used as the carbon donor to generate the treatment atmosphere.
Zum Nitrocarburieren von metallischen Werkstücken kommen verschiedene Gasgemische zum Einsatz. Stickstoffspender ist dabei grundsätzlich Ammoniak (NH3), während als Kohlenstoffspender verschiedene Gasgemische wie beispielsweise Luft- Kohlenwasserstoff-Gemische (Endogas und Exogas) sowie Kohlendioxid zum Einsatz kommen. Im Nitrierofen reagieren diese Gase mit vorhandenem Wasserstoff, wobei sich je nach thermischen und chemischen Bedingungen eine stationäre Kohlenstoff-, Stickstoff und Sauerstoffaktivität einstellt.Various gas mixtures are used to nitrocarburize metallic workpieces. The nitrogen donor is basically ammonia (NH 3 ), while various gas mixtures such as air-hydrocarbon mixtures (endogas and exogas) and carbon dioxide are used as carbon donors. In the nitriding furnace, these gases react with the hydrogen present, with stationary carbon, nitrogen and oxygen activity depending on the thermal and chemical conditions.
Der bei der Ammoniakspaltung entstehende atomare Stickstoff reagiert bei Kontakt mit Metalloberflächen (im folgenden als (N)ad bezeichnet) besonders leicht mit dem Metall unter Bildung von Nitriden. In Verbindung mit Eisen können sich unterschiedliche Nitrid-Phasen bilden. Bei Stählen werden im Hinblick auf eine hohe Härte und Verschleißfestigkeit beispielsweise Nitrid-Phasen in Form von sogenanntem ε-Nitrid (Fβ2-3N) und γ'-Nitrid (Fβ4N) oder Gemische dieser Nitride bevorzugt. Die bei der Nitridbildung von Fe-haltigen Metallen ablaufenden Reaktionen lassen sich schematisch anhand folgender chemischer Gleichungen beschreiben:The atomic nitrogen produced during ammonia splitting reacts particularly easily with the metal to form nitrides when it comes into contact with metal surfaces (hereinafter referred to as (N) a d). Different nitride phases can form in connection with iron. In the case of steels, nitride phases in the form of so-called ε-nitride (Fβ2-3N) and γ'-nitride (Fβ4N) or mixtures of these nitrides, for example, are preferred with regard to high hardness and wear resistance. The reactions taking place during the nitride formation of Fe-containing metals can be described schematically using the following chemical equations:
(1) NH3 = (N)ad + 1 ,5 H2 (1) NH 3 = (N) ad + 1.5 H 2
(2a) (N)ad + 4 Fe = Fe4N (γ'-Nitrid)(2a) (N) ad + 4 Fe = Fe 4 N (γ'-nitride)
(2b) (N)ad + 2-3 Fe = Fe2-3N (ε-Nitrid)(2b) (N) a d + 2-3 Fe = Fe 2-3 N (ε-nitride)
Der im Nitrid gelöste Kohlenstoff wirkt sich auf Morphologie, Kompaktheit, Porensaum und Haftung der Verbindungsschicht und deren Korrosions- und Verschleißbeständigkeit aus. Darüberhinaus hat es sich gezeigt, daß Art und Umfang der Nitridbildung durch die Kohlenstoffaktivität in der Nitrieratmosphäre wesentlich beeinflußt wird. Die Kohlenstoffaktivität wiederum hängt von dem eingesetztenThe carbon dissolved in the nitride affects morphology, compactness, pore hem and adhesion of the connection layer and its corrosion and Wear resistance. In addition, it has been shown that the type and extent of nitride formation is significantly influenced by the carbon activity in the nitriding atmosphere. The carbon activity in turn depends on the one used
Kohlenstoffspender ab. Sie fällt in der Reihenfolge Propan, Endogas, Exogas und Kohlendioxid ab. Da die Zusammensetzung der Gasphase im Nitrierofen somit wesentlichen Einfluß auf das Ergebnis der Nitrocarbuherung hat, ist es günstig, wenn diese in möglichst weiten Bereichen einstellbar ist.Carbon donor. It drops in the order of propane, endogas, exogas and carbon dioxide. Since the composition of the gas phase in the nitriding furnace thus has a significant influence on the result of the nitrocarburization, it is advantageous if it can be set within as wide a range as possible.
Bei den bekannten Gasgemischen liegen die Kohlendioxidgehalte üblicherweise zwischen 4 und 10 Vol.-%. Das Kohlendioxid wird direkt in den Ofenraum des Nitrierofens dosiert und reagiert dort teilweise mit Wasserstoff nach folgender Reaktionsgleichung:In the known gas mixtures, the carbon dioxide contents are usually between 4 and 10% by volume. The carbon dioxide is metered directly into the furnace chamber of the nitriding furnace, where it partially reacts with hydrogen according to the following reaction equation:
(3) Cθ2+H2=CO+H2θ(3) Cθ2 + H2 = CO + H2θ
Üblicherweise wird der Nitrierofen permanent mit Frischgas durchströmt, so daß sich in der Gasphase kein chemisches Gleichgewicht einstellt. Es ergibt sich dadurch eine stationäre Kohlenstoffaktivität (ac,B), die im wesentlichen von konkreten Gegebenheiten im Nitrierofen, wie etwa der Oberfläche der zu behandelnden Werkstücke, der Nitriertemperatur, der Gaszusammensetzung und demNormally, fresh gas flows through the nitriding furnace permanently, so that no chemical equilibrium is established in the gas phase. This results in a stationary carbon activity (a c , B), which essentially depends on specific conditions in the nitriding furnace, such as the surface of the workpieces to be treated, the nitriding temperature, the gas composition and the
Gasvolumenstrom abhängt und die von außen kaum zu regeln ist. Es pendelt sich somit eine den vorherrschenden Gegebenheiten angepaßte Kohlenstoffaktivität (ac,B) ein, die nach der Boudouard-Reaktion definiert werden kann:Gas volume flow depends and which can hardly be regulated from the outside. A carbon activity (a c, B ), which is adapted to the prevailing conditions, settles down and can be defined according to the Boudouard reaction:
2 CO = C+ CO22 CO = C + CO2
Figure imgf000004_0001
Figure imgf000004_0001
KB bezeichnet dabei die Konstante des Boudouard-Gleichgewichts. Beim Einspeisen von Kohlendioxid direkt in den Nitrierofen stellt sich eine Kohlenstoffaktivität von maximal 1 ein, was einer Aktivität von reinem Graphit entspricht. Unter diesen Bedingungen kann die Bildung von ε-Nitrid (Fe2-3N) aber nur durch eine hohe Nitrierkennzahl (KN) von größer 1 realisiert werden. Im Hinblick hierauf ist auf die DE-C1 197 19 225 zu verweisen, aus der ein Verfahren für die Regelung der Nitrierkennzahl einer Nitrier- bzw. Nitrocarburieratmosphäre in einer Ofenanlage bei Einsatz von NH3 als Stickstoffquelle bekannt ist. Das bekannte Verfahren zeichnet sich dadurch aus, dass der NH3-Gasdurchsatz konstant gehalten wird, und lediglich der Arbeitspunkt des Vorspalters, in dem das NH3-Spaltgas erzeugt wird, geregelt wird. Eine hohe Nitrierkennzahl erfordert einen hohen Ammoniakgehalt im Nitrierofen, was wiederum einen hohen Rest-Ammoniakgehalt im Ofenabgas zur Folge hat, das ungenutzt den Ofen verläßt.K B denotes the constant of the Boudouard equilibrium. When carbon dioxide is fed directly into the nitriding furnace, the maximum carbon activity is 1, which corresponds to the activity of pure graphite. Under these conditions, the formation of ε-nitride (Fe 2-3 N) can only be achieved by a high nitriding index (K N ) of greater than 1. With regard to this, reference is made to DE-C1 197 19 225, from which a method for regulating the nitriding index of a nitriding or nitrocarburizing atmosphere in a furnace system when using NH 3 as a nitrogen source is known. The known method is characterized in that the NH 3 gas throughput is kept constant and only the operating point of the pre-splitter in which the NH 3 split gas is generated is regulated. A high nitriding index requires a high ammonia content in the nitriding furnace, which in turn results in a high residual ammonia content in the furnace exhaust gas, which leaves the furnace unused.
Dieser Effekt stellt sich auch bei dem in der DE-A1 42 29 803 vorgeschlagenen Verfahren ein, wonach die Nitrierkennzahl für die Kontrolle einer Nitrier- bzw. Nitrocarburieratmosphäre eingesetzt wird, wobei die Nitrierkennzahl durch Messung des O2-Gehalts der Atmosphäre unter Einsatz einer O2-Sonde ermittelt wird.This effect also occurs in the process proposed in DE-A1 42 29 803, according to which the nitriding index is used to control a nitriding or nitrocarburizing atmosphere, the nitriding index being measured by measuring the O 2 content of the atmosphere using an O 2 probe is determined.
In der DE-A1 195 14 932 wird zur Erzeugung einer Carbonitrier- Atmosphäre vorgeschlagen, dem Ofen Kohlenwasserstoffe und eine oxidierende Komponente, wie Luft oder CO2, und Ammoniak direkt zuzuführen. Um einen geregelten, möglichst hohen CO-Gehalt in der Carbonitrier-Atmosphäre zu erreichen, wird der CO-Gehalt gemessen und bei Erreichen einer vorgegebenen Untergrenze eine CO-bildendeIn DE-A1 195 14 932 to generate a carbonitriding atmosphere it is proposed to supply the furnace with hydrocarbons and an oxidizing component, such as air or CO 2 , and ammonia. In order to achieve a regulated, as high as possible CO content in the carbonitriding atmosphere, the CO content is measured and, when a predetermined lower limit is reached, a CO-forming
Substanz, wie Methanol, in den Ofenraum eingespeist. Bei diesem Verfahren werden die CO-bildenden Komponenten wie Methanol oder CO2 somit direkt in den Behandlungsraum eingespeist. Beim Aufkohlen oder Carbonitrieren ist dies aufgrund der dabei herrschenden hohen Temperaturen effektiv, jedoch nicht bei den üblichen, relativ niedrigen Nitriertemperaturen von max. 580°C. Bei diesen niedrigeren Temperaturen spaltet Methanol nicht stöchiometrisch, sondern es bilden sich unerwünschte Spaltprodukte wie CH4 und andere höhere Kohlenwasserstoffe, CO2, Aldehyde, Ketone usw, die teilweise giftig und bei Kondensation ätzend sind. Zudem hängt die Spaltung des Methanols stark von den Gegebenheiten des Heizraumes und von der Chargenoberfläche ab, so dass die Reproduzierbarkeit der gewünschten Ofengaszusammensetzung nicht gegeben ist. Dies hat weiterhin zur Folge, dass sich durch unkontrollierten Spaltreaktionen Ruß auf dem Chargenmaterial und der Heizraumoberfläche abscheidet oder unerwünschte Carbide gebildet. Der Erfindung liegt daher die Aufgabe zugrunde, das bekannte Verfahren zum Nitrocarburieren metallischer Werkstücke unter Einsatz von Kohlendioxid als Kohlenstoffspender so zu modifizieren, daß Art und Umfang der Nitridbildung in weitem Rahmen einstellbar sind.Substance such as methanol is fed into the furnace space. In this process, the CO-forming components such as methanol or CO 2 are thus fed directly into the treatment room. When carburizing or carbonitriding, this is effective due to the high temperatures involved, but not at the usual, relatively low nitriding temperatures of max. 580 ° C. At these lower temperatures, methanol does not cleave stoichiometrically, but undesirable cleavage products such as CH 4 and other higher hydrocarbons, CO 2 , aldehydes, ketones, etc. are formed, some of which are toxic and corrosive when condensed. In addition, the cleavage of the methanol strongly depends on the conditions in the boiler room and on the surface of the batch, so that the desired furnace gas composition cannot be reproduced. This also has the consequence that soot deposits on the batch material and the boiler room surface due to uncontrolled cracking reactions or undesired carbides are formed. The invention is therefore based on the object of modifying the known method for nitrocarburizing metallic workpieces using carbon dioxide as a carbon donor so that the type and extent of nitride formation can be adjusted within a wide range.
Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß ein Kohlendioxid-haltiger Gasstrom in einen dem Behandlungsraum vorgeschalteten Reaktor eingeleitet und darin durch Reaktion mit einem Wasserstoffspender bei einer Reaktionstemperatur oberhalb der Behandlungstemperatur zu einem Kohlungsgas modifiziert wird, das eine im Vergleich zum Kohlendioxid-haltigen Gasstrom höhere Kohlenstoffaktivität bei der Behandlungstemperatur aufweist.This object is achieved in that a carbon dioxide-containing gas stream is introduced into a reactor upstream of the treatment room and is modified therein by reaction with a hydrogen donor at a reaction temperature above the treatment temperature to give a carbonization gas which has a higher carbon activity than the carbon dioxide-containing gas stream at the treatment temperature.
Der Kohlendioxid-haltige Gasstrom wird erfindungsgemäß einem Reaktor zugeführt, darin in Richtung einer höheren Kohlenstoffaktivität modifiziert und anschließend als Kohlungsgas in den Behandlungsraum eingeleitet. Die Modifizierung beruht auf einer According to the invention, the gas stream containing carbon dioxide is fed to a reactor, modified therein in the direction of a higher carbon activity and then introduced into the treatment room as carbonizing gas. The modification is based on a

Claims

Patentansprüche claims
1. Verfahren zum Nitrocarburieren metallischer Werkstücke, indem die Werkstücke in einer Stickstoff, Kohlenmonoxid und Wasserstoff enthaltenden1. Process for nitrocarburizing metallic workpieces by placing the workpieces in a containing nitrogen, carbon monoxide and hydrogen
Behandlungsatmosphäre bei einer Behandlungstemperatur in einem Behandlungsraum behandelt werden, wobei zur Erzeugung der Behandlungsatmosphäre Kohlendioxid als Kohlenstoffspender eingesetzt wird, dadurch gekennzeichnet, daß ein Kohlendioxid-haltiger Gasstrom (1 ; 21) in einen dem Behandlungsraum (6; 27) vorgeschalteten Reaktor (4; 24) eingeleitet und darin durch Reaktion mit einem Wasserstoffspender (2; 22) bei einer Reaktionstemperatur oberhalb der Behandlungstemperatur zu einem Kohlungsgas (5; 25) modifiziert wird, das eine im Vergleich zum Kohlendioxid-haltigen Gasstrom (1 ; 21) höhere Kohlenstoffaktivität bei der Behandlungstemperatur aufweist.Treatment atmosphere are treated at a treatment temperature in a treatment room, carbon dioxide being used as a carbon donor to generate the treatment atmosphere, characterized in that a gas stream (1; 21) containing carbon dioxide is introduced into a reactor (4; 24) upstream of the treatment room (6; 27) ) is introduced and modified therein by reaction with a hydrogen donor (2; 22) at a reaction temperature above the treatment temperature to give a carburizing gas (5; 25) which has a higher carbon activity at the treatment temperature than the gas stream containing carbon dioxide (1; 21) having.
2. Verfahren nach Anspruch 1 , dadurch gekennzeichnet, daß als Wasserstoffspender ein Kohlenwasserstoff-haltiges Fluid (2) eingesetzt wird.2. The method according to claim 1, characterized in that a hydrocarbon-containing fluid (2) is used as the hydrogen donor.
3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß als Wasserstoffspender Erdas, Propan oder Methan (2) eingesetzt wird.3. The method according to claim 1 or 2, characterized in that Erdas, propane or methane (2) is used as hydrogen donor.
4. Verfahren nach Anspruch 1 , dadurch gekennzeichnet, daß als Wasserstoffspender Ammoniak (22) eingesetzt wird.4. The method according to claim 1, characterized in that ammonia (22) is used as the hydrogen donor.
5. Verfahren nach Anspruch 4, dadurch gekennzeichnet, daß als Reaktor ein Spaltgerät (24) für Ammoniak eingesetzt wird.5. The method according to claim 4, characterized in that a splitting device (24) for ammonia is used as the reactor.
6. Verfahren nach Anspruch 4 oder 5, dadurch gekennzeichnet, daß dem Kohlungsgas (5; 25) vor Einleitung in den Behandlungsraum (6; 27) Feuchtigkeit entzogen wird.6. The method according to claim 4 or 5, characterized in that the carbonization gas (5; 25) moisture is removed before introduction into the treatment room (6; 27).
7. Verfahren nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß eine Regelung (9; 30) für die Kohlenstoffaktivität im Behandlungsraum (6; 27) vorgesehen ist, bei der als Stellgröße die Zufuhrrate eines den Wasserstoffspender (2; 22) enthaltenden Teilstromes dient.7. The method according to any one of claims 1 to 6, characterized in that a control (9; 30) for the carbon activity in the treatment room (6; 27) is provided in which the feed rate of a partial stream containing the hydrogen donor (2; 22) serves as the manipulated variable.
8. Verfahren nach Anspruch 7, dadurch gekennzeichnet, daß die Regelung (9; 30) für die Kohlenstoffaktivität eine Messung der Sauerstoffaktivität (8; 29) und/oder der8. The method according to claim 7, characterized in that the control (9; 30) for the carbon activity a measurement of the oxygen activity (8; 29) and / or
Kohlenmonoxidkonzentration im Behandlungsraum (6; 27) umfaßt.Carbon monoxide concentration in the treatment room (6; 27).
9. Verfahren nach einem der Ansprüche 7 oder 8, dadurch gekennzeichnet, daß dem Kohlendioxid-haltigen Gasstrom (1 ; 21), dem Kohlungsgas (5; 25) und/oder dem Teilstrom für den Wasserstoffspender (2; 22) ein Verdünnungsgas (3; 23) beigemischt wird.9. The method according to any one of claims 7 or 8, characterized in that the carbon dioxide-containing gas stream (1; 21), the carburizing gas (5; 25) and / or the partial stream for the hydrogen donor (2; 22) is a diluent gas (3rd ; 23) is added.
10.Verfahren nach einem der Ansprüche 1 bis 9, dadurch gekennzeichnet, daß das Kohlungsgas (25) vor Einleitung in den Behandlungsraum (27) auf eine Temperatur im Bereich der Behandlungstemperatur abgekühlt wird.10.The method according to any one of claims 1 to 9, characterized in that the carburizing gas (25) is cooled to a temperature in the region of the treatment temperature before being introduced into the treatment room (27).
11.Verfahren nach einem der Ansprüche 1 bis 9, dadurch gekennzeichnet, daß das Kohlungsgas (5) bei Einleitung in den Behandlungsraum (6) eine Temperatur im Bereich der Reaktionstemperatur aufweist.11. The method according to any one of claims 1 to 9, characterized in that the carbonizing gas (5) has a temperature in the region of the reaction temperature when introduced into the treatment room (6).
12.Verfahren nach einem der Ansprüche 1 bis 11 , dadurch gekennzeichnet, daß die Behandlungstemperatur im Bereich zwischen 500 °C und 700 °C liegt.12.The method according to any one of claims 1 to 11, characterized in that the treatment temperature is in the range between 500 ° C and 700 ° C.
13.Verfahren nach einem der Ansprüche 1 bis 12, dadurch gekennzeichnet, daß die Reaktionstemperatur im Bereich zwischen 800 und 1150 °C liegt. 13.The method according to any one of claims 1 to 12, characterized in that the reaction temperature is in the range between 800 and 1150 ° C.
PCT/EP2000/007576 1999-08-25 2000-08-04 Method for nitro-carburization of metal workpieces WO2001014611A1 (en)

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Application Number Priority Date Filing Date Title
AT00962293T ATE257865T1 (en) 1999-08-25 2000-08-04 PROCESS FOR NITROCARBURIZING METALLIC WORKPIECES
DE50005043T DE50005043D1 (en) 1999-08-25 2000-08-04 METHOD FOR NITROCARBURING METAL WORKPIECES
EP00962293A EP1230415B1 (en) 1999-08-25 2000-08-04 Method for nitro-carburization of metal workpieces
PL00353217A PL195105B1 (en) 1999-08-25 2000-08-04 Method for nitro-carburization of metal workpieces

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DE19940370A DE19940370C2 (en) 1999-08-25 1999-08-25 Process for nitrocarburizing metallic workpieces
DE19940370.8 1999-08-25

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PL353217A1 (en) 2003-11-03
DE19940370C2 (en) 2001-07-12
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EP1230415A1 (en) 2002-08-14
DE19940370A1 (en) 2001-03-01
ES2214316T3 (en) 2004-09-16
DE50005043D1 (en) 2004-02-19

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