DE19509614A1 - Controlling nitriding value of nitriding and nitrocarburisation atmos - Google Patents

Controlling nitriding value of nitriding and nitrocarburisation atmos

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Publication number
DE19509614A1
DE19509614A1 DE1995109614 DE19509614A DE19509614A1 DE 19509614 A1 DE19509614 A1 DE 19509614A1 DE 1995109614 DE1995109614 DE 1995109614 DE 19509614 A DE19509614 A DE 19509614A DE 19509614 A1 DE19509614 A1 DE 19509614A1
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DE
Germany
Prior art keywords
nitriding
regulation
ammonia
atmospheres
nitrocarburizing
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.)
Withdrawn
Application number
DE1995109614
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German (de)
Inventor
Hans Ruediger Dr Ing Hoffmann
Karl-Helmut Dipl Ing Weissohn
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Individual filed Critical Individual
Priority to DE1995109614 priority Critical patent/DE19509614A1/en
Publication of DE19509614A1 publication Critical patent/DE19509614A1/en
Withdrawn legal-status Critical Current

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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
    • C23C8/28—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
    • 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
    • C23C8/24—Nitriding

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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)

Abstract

Method for controlling the specific nitriding value or other equivalent specific value of nitriding and nitrocarburising atmospheres comprises using ammonia dissociation gas and flow controllers whereby a constant total amt. of ammonia is fed to the furnace simultaneously directly and via an ammonia predissociation unit. In the control of nitrocarburisation atmospheres, CO and CO2 may be added simultaneously as separate gases for carbon transfer, esp. where the total CO + CO2 input is held constant, and partic. where the ratio of total CO + CO2 to total NH3 input is held constant at between 2-10%.

Description

Die Regelung der Nitrierkennzahl, des Ammoniakspaltgrades oder einzelner Gaskomponenten von Nitrier- bzw. Nitrocarbu­ rieratmosphären während eines Nitrier- bzw. Nitrocarburier­ prozesses unter Verwendung von bereits vorgespaltenem Ammo­ niak ist bekannt. Üblicherweise wird dabei dem Ofen alternativ entweder ungespaltener oder bereits vorgespalte­ ner Ammoniak zugeführt. Eine derartige Regelung galt bisher durchaus als ausreichend, obwohl bei diesem Regelungsvorgang deutliche Regelschwankungen kaum vermieden werden können. Ein langsames Auf- und Zuregeln von ungespaltenem bzw. vor­ gespaltenem Ammoniak über Mengendurchflußregler, sodaß gleichzeitig sowohl ungespaltener wie auch vorgespaltener Ammoniak in den Ofenraum eingeleitet wird, reduziert die Regelschwankungen.The regulation of the nitriding index, the degree of ammonia splitting or individual gas components of nitriding or nitrocarbu atmosphere during a nitriding or nitrocarburizing process using pre-split ammo niak is known. Usually the oven alternatively either unsplit or already split added ammonia. Such a regulation has previously applied quite sufficient, although in this regulatory process significant control fluctuations can hardly be avoided. A slow opening and closing of unsplit or before split ammonia over mass flow controller, so that both unsplit and pre-split at the same time Introducing ammonia into the furnace chamber reduces the Control fluctuations.

Für eine Weiterverarbeitung der Regelergebnisse ist es vor­ teilhaft, wenn die maximalen Einzelmengen an ungespaltenem und vorgespaltenem Ammoniak nicht unabhängig voneinander vorgegeben werden, sondern wenn sie in einer festen Bezie­ hung zueinander stehen. Hierbei hat sich wiederum als vor­ teilhaft erwiesen, wenn die Summe der jeweiligen Einzelmen­ gen - das heißt die Ammoniakmenge, die dem Ofen ungespalten zugeführt wird, als auch die Ammoniakmenge, die zunächst durch eine Vorspalteinrichtung geleitet und dann erst dem Ofen zugeführt wird, - über einen bestimmten Zeitraum hinweg einen konstanten Wert beibehält. Wird zum Beispiel nach einer gewissen Regeldauer als Ereignis festgestellt, daß überwiegend oder ausschließlich ungespaltener Ammoniak zuge­ geben wurde, um einen bestimmten Vorgabewert zu erreichen, dann kann dies nach bestimmten Gesichtspunkten zu einer Anhebung des Vorgabewertes für die Gesamtmenge benutzt wer­ den. Umgekehrt kann die Gesamtmenge reduziert und damit Ammoniak eingespart werden, wenn zur Aufrechterhaltung des Regelwertes über einen gewissen Zeitraum hinweg überwiegend vorgespaltener Ammoniak der Ofenanlage zugeführt wurde. Dabei ist allerdings zu berücksichtigen, daß aus Sicher­ heitsgründen und somit Anlagen-abhängig gewisse minimale Gesamtmengen nicht unterschritten werden dürfen.It is planned for further processing of the rule results partial if the maximum individual amounts of uncleaved and pre-split ammonia are not independent of each other be specified, but if they are in a fixed relationship hung to each other. This, in turn, has proven to be proven in part if the sum of the respective individual men gen - that is the amount of ammonia that is not split in the furnace is fed, as well as the amount of ammonia that initially passed through a pre-splitting device and only then Furnace is fed - over a certain period of time maintains a constant value. For example, after a certain rule duration as an event that predominantly or exclusively undissolved ammonia was given to achieve a certain default value then this can lead to a certain point of view Raising the default value for the total quantity used the. Conversely, the total amount can be reduced and thus Ammonia can be saved when maintaining the Rule values predominantly over a certain period of time pre-split ammonia was fed to the furnace. However, it must be taken into account that for sure safety reasons and thus certain minimum depending on the system Total quantities must not be undercut.

Bisher war es nicht möglich, die Wirkung des Kohlenstoffein­ flusses beim Nitrocarburieren gleichzeitig und dabei auch unabhängig von der Wirkung des Stickstoffeinflusses zu steu­ ern bzw. sogar zu regeln. Dies wird erfindungsgemäß dadurch ermöglicht, daß dem Nitrocarburierprozeß über Durchflußmen­ genregler gleichzeitig sowohl Kohlenmonoxid als auch Kohlen­ dioxid zugeführt werden. Durch eine geeignete Mischung bei­ der Komponenten kann jeder beliebige Vorgabewert für eine Carburierkennzahl oder Kohlenstoffaktivität vorgegeben wer­ den und zwar unabhängig von der Nitrierkennzahl oder einer anderen äquivalenten Kenngröße. Auch in diesem Fall hat es sich für die Weiterverarbeitung der Regelergebnisse als vor­ teilhaft erwiesen, wenn die Summe der dem Ofen zugeführten Gesamtmenge an Kohlenmonoxid plus Kohlendioxid zumindest für eine gewisse Dauer konstant gehalten wird. Desgleichen erwies es sich für die Prozeßsteuerung als vorteilhaft, wenn die Gesamtmenge an Kohlenmonoxid plus Kohlendioxid während jedes Zeitpunktes des Nitrocarburierprozesses zur Gesamt­ menge Ammoniak in einem festen Verhältnis steht. Verhältnis­ werte zwischen 2 und 10% von der zugeführten Ammoniakmenge sind als besonders zweckmäßig anzusehen.So far it has not been possible to control the effect of carbon flows with nitrocarburizing at the same time and also too tax independent of the effect of nitrogen influence or even to regulate. This is according to the invention allows the nitrocarburizing process to flow through regulator both carbon monoxide and carbon at the same time dioxide are added. With a suitable mixture The components can have any default value for a Carburier key figure or carbon activity specified regardless of the nitriding index or one other equivalent parameter. In this case too opting for further processing of the rule results as before Proven partially if the sum of the fed to the furnace Total amount of carbon monoxide plus carbon dioxide at least for a certain duration is kept constant. The same it proved to be advantageous for process control if the total amount of carbon monoxide plus carbon dioxide during every point in the nitrocarburizing process to the total amount of ammonia is in a fixed ratio. Ratio values between 2 and 10% of the amount of ammonia supplied are particularly useful.

Claims (5)

1. Eine Regelung der Nitrierkennzahl oder einer anderen äquivalenten Kenngröße von Nitrier- und Nitrocarburierat­ mosphären unter Verwendung von Ammoniakspaltgas und Mengen­ durchflußreglern dadurch gekennzeichnet, daß während der Regelung die Gesamtmenge an Ammoniak, die dem Ofen gleich­ zeitig direkt und über eine Vorspalteinrichtung zugeführt wird, konstant gehalten wird.1. A regulation of the nitriding index or another equivalent parameter of nitriding and nitrocarburierate atmospheres using ammonia cracking gas and flow regulators characterized in that during the regulation the total amount of ammonia which is simultaneously fed to the furnace directly and via a pre-splitting device is constant is held. 2. Eine Regelung von Nitrocarburieratmosphären dadurch gekennzeichnet, daß gleichzeitig sowohl Kohlenmonoxid als auch Kohlendioxid als Einzelgase für die Kohlenstoffübertra­ gung verwendet werden.2. A regulation of nitrocarburizing atmospheres characterized in that both carbon monoxide and also carbon dioxide as single gases for carbon transmission be used. 3. Eine Regelung von Nitrocarburieratmosphären gemäß Ansprü­ chen 1 und 2 dadurch gekennzeichnet, daß die Carburierkenn­ zahl oder eine andere äquivalente Kenngröße einer Nitrocar­ burieratmosphäre durch entsprechende Dosierung von Kohlenmonoxid und -dioxid unter Verwendung von Massendurch­ flußreglern geregelt wird; und zwar derart, daß die Summe der zugegebenen Gesamtmenge Kohlenmonoxid plus Kohlendioxid konstant gehalten wird.3. A regulation of nitrocarburizing atmospheres according to claims chen 1 and 2, characterized in that the carburizing number or another equivalent parameter of a nitrocar burier atmosphere by appropriate dosing of Carbon monoxide and dioxide using bulk river regulators is regulated; in such a way that the sum the total amount of carbon monoxide added plus carbon dioxide is kept constant. 4. Eine Regelung von Nitrocarburieratmosphären gemäß Ansprü­ chen 1 bis 3 dadurch gekennzeichnet, daß das Verhältnis der Gesamtmenge Kohlenmonoxid plus Kohlendioxid im Vergleich zur Gesamtmenge Ammoniak bei einem Wert zwischen 2 und 10% kon­ stant gehalten wird.4. A regulation of nitrocarburizing atmospheres according to claims chen 1 to 3, characterized in that the ratio of Total amount of carbon monoxide plus carbon dioxide compared to Total amount of ammonia at a value between 2 and 10% con is kept constant. 5. Eine Regelung von Nitrier- bzw. Nitrocarburieratmosphären gemäß Ansprüchen 1 bis 4 dadurch gekennzeichnet, daß im Ver­ lauf eines Nitrier- oder Nitrocarburierprozesses die genann­ ten Gesamtmengen gemäß Ansprüchen 1 und 3 sowie das Mengen­ verhältnis gemäß Anspruch 4 nach Vorgabe oder nach ereignisabhängigen Gesichtspunkten verändert werden.5. A regulation of nitriding or nitrocarburizing atmospheres according to claims 1 to 4, characterized in that in ver run a nitriding or nitrocarburizing process called total amounts according to claims 1 and 3 and the amounts ratio according to claim 4 as specified or event-related aspects are changed.
DE1995109614 1995-03-21 1995-03-21 Controlling nitriding value of nitriding and nitrocarburisation atmos Withdrawn DE19509614A1 (en)

Priority Applications (1)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19652125C1 (en) * 1996-12-14 1998-04-30 Volker Dipl Ing Leverkus Nitriding or carbonitriding atmosphere regulation
EP1122330A1 (en) * 2000-02-04 2001-08-08 Ipsen International GmbH Process and use of an apparatus for nitrocarburizing of metallic parts

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19652125C1 (en) * 1996-12-14 1998-04-30 Volker Dipl Ing Leverkus Nitriding or carbonitriding atmosphere regulation
EP1122330A1 (en) * 2000-02-04 2001-08-08 Ipsen International GmbH Process and use of an apparatus for nitrocarburizing of metallic parts
US6406560B1 (en) 2000-02-04 2002-06-18 Ipsen International Gmbh Method for the thermal treatment of metal

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