EP1122331A1 - Process of nitriding and/or carbonitriding of high-alloyed steel - Google Patents
Process of nitriding and/or carbonitriding of high-alloyed steel Download PDFInfo
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- EP1122331A1 EP1122331A1 EP00102359A EP00102359A EP1122331A1 EP 1122331 A1 EP1122331 A1 EP 1122331A1 EP 00102359 A EP00102359 A EP 00102359A EP 00102359 A EP00102359 A EP 00102359A EP 1122331 A1 EP1122331 A1 EP 1122331A1
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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
- C23C8/08—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
- C23C8/26—Nitriding of ferrous surfaces
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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
- C23C8/34—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 more than one step
Definitions
- the invention relates to a method for heat treatment of metallic Workpieces, especially for nitriding or nitrocarburizing alloyed Ferrous materials, such as higher alloy steels.
- the invention further relates on the use of a device for performing such a method.
- thermochemical heat treatment To create defined workpiece properties, such as a high one Wear resistance or sufficient corrosion resistance metallic workpieces are subjected to a thermochemical heat treatment.
- the result of the heat treatment is, for example, nitriding or nitrocarburizing Enriching the edge layer of the workpieces with nitrogen and / or Carbon in order to achieve the required mechanical and to impart chemical properties on the surface and in the edge area.
- the surface layer is enriched with nitrogen by the ammonia (NH 3 ) contained in a reaction gas at temperatures of generally over 500 ° C under the catalytic effect of the surface of the workpieces to be nitrided breaks down into nitrogen (N) and hydrogen (H).
- the ammonia molecule is adsorbed and gradually degraded on the workpiece surface, releasing the required nitrogen in atomic form and making it available for solution in iron and for the formation of iron nitride (Fe x N).
- the surface layer is simultaneously enriched with carbon.
- Atomic carbon (C) diffuses in an analogous manner through the workpiece surface into the boundary layer.
- the surface layer which, in addition to hexagonal ⁇ -nitride (Fe 2-3 N), also face-centered cubic ⁇ '-nitride (Fe 4 N) and also nitrides of nitride-forming alloy elements, such as chromium, molybdenum, manganese, titanium, niobium, tungsten, vanadium or aluminum nitride.
- the invention has for its object to provide a method for the heat treatment of metallic workpieces, in which a largely uniform nitriding layer can be achieved even with workpieces consisting of higher alloyed iron materials.
- Such a procedure embraces the surprising finding that a largely uniform nitriding layer can be achieved if the Workpieces before the actual heat treatment in process step d, for example, nitriding or nitrocarburizing, initially only in one ammonia-containing gas atmosphere warmed and then in an additional one Gas atmosphere containing oxidizing agent to the treatment temperature,
- the nitriding temperature, heated and then for a certain Duration may be kept at this temperature with the result that possibly in the case of high-alloy materials, existing passive layers are eliminated or something that be converted into a uniform diffusion of nitrogen into the Material is favored.
- the temperature at which in each Process steps is heated, and the length of time for which the workpieces in the respective gas atmospheres are based on the Composition of the reaction gas and the material to be treated Workpieces and the desired treatment success.
- the ratio of the amounts of ammonia and the oxidizing agent in the gas atmosphere is expediently between 1: 1 and 5: 1 if air is used as the oxidizing agent and between 1: 0.1 and 1: 1 if carbon dioxide, water vapor or nitrogen dioxide Oxidizing agents are used.
- a particularly advantageous procedure is also given when the Time period when the workpieces are kept in an ammonia or Ammonia and the carbon-donating gas atmosphere in Dependence on the desired thickness of the surface layer to be enriched is chosen.
- Procedural management may also be useful as carbon donor substance carbon dioxide, carbon monoxide or Hydrocarbons can be used individually or as a mixture.
- the workpieces in one reducing or neutral gas atmosphere for example from an endogas or nitrogen, or in a liquid quenching medium Room temperature can be cooled to an economically beneficial Ensure procedure.
- the first workpiece sample shown in FIG. 1 was preheated to a temperature of approximately 450 ° C. in an endogas-containing gas atmosphere and then in a reaction gas consisting of 50 vol.% Ammonia (NH 3 ) and 50 vol.% Endogas the nitriding temperature of approx. 580 ° C warmed. After approximately 240 minutes, during which the workpiece sample was exposed to the gas atmosphere at this temperature, the workpiece sample was cooled to room temperature in an endogenous gas atmosphere.
- a reaction gas consisting of 50 vol.% Ammonia (NH 3 ) and 50 vol.% Endogas the nitriding temperature of approx. 580 ° C warmed.
- the second workpiece sample shown in Fig. 2 was first preheated in an ammonia-containing gas atmosphere to a temperature of about 450 ° C and then in an ammonia-containing reaction gas, the air as an oxidizing agent in a ratio of 3.5 (ammonia): 1 (air ) was added, heated to the nitriding temperature of approx. 580 ° C. The workpiece sample was then held at this temperature and in this gas atmosphere for a period of about 1.5 hours. The gas atmosphere was then exchanged and the workpiece sample was exposed at 580 ° C.
- the comparison of the micrographs shown in the drawing shows that the 1, structure of the first produced by conventional nitriding Workpiece sample in the range from 0 ⁇ m to 40 ⁇ m from the edge uneven nitriding layer, while that after the last Methodically generated nitriding layer of the second workpiece sample is evenly formed.
- Iron materials such as stainless steels
- their high corrosion resistance is inextricably linked to surface passivation, on proportionate achieve better treatment results in a simple way.
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- Engineering & Computer Science (AREA)
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- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren zur Wärmebehandlung metallischer Werkstücke, insbesondere zum Nitrieren oder Nitrocarburieren von legierten Eisenwerkstoffen, wie höher legierten Stählen. Die Erfindung bezieht sich ferner auf die Verwendung einer Vorrichtung zur Durchführung eines solchen Verfahrens.The invention relates to a method for heat treatment of metallic Workpieces, especially for nitriding or nitrocarburizing alloyed Ferrous materials, such as higher alloy steels. The invention further relates on the use of a device for performing such a method.
Zum Erzeugen von definierten Werkstückeigenschaften, wie etwa einer hohen Verschleißfestigkeit oder ausreichender Korrosionsbeständigkeit, werden metallische Werkstücke einer thermochemischen Wärmebehandlung unterzogen. Das Ergebnis der Wärmebehandlung ist etwa beim Nitrieren oder Nitrocarburieren die Anreicherung der Randschicht der Werkstücke mit Stickstoff und/oder Kohlenstoff, um hierdurch den Werkstücken die geforderten mechanischen und chemischen Eigenschaften an der Oberfläche und im Randbereich zu verleihen.To create defined workpiece properties, such as a high one Wear resistance or sufficient corrosion resistance metallic workpieces are subjected to a thermochemical heat treatment. The result of the heat treatment is, for example, nitriding or nitrocarburizing Enriching the edge layer of the workpieces with nitrogen and / or Carbon in order to achieve the required mechanical and to impart chemical properties on the surface and in the edge area.
Beim Nitrieren, zum Beispiel in einer ammoniakhaltigen Gasatmosphäre, erfolgt die Anreicherung der Randschicht mit Stickstoff dadurch, dass der in einem Reaktionsgas enthaltene Ammoniak (NH3) bei Temperaturen von in der Regel über 500 °C unter der katalytischen Wirkung der Oberfläche der zu nitrierenden Werkstücke in Stickstoff (N) und Wasserstoff (H) zerfällt. Hierbei wird an der Werkstückoberfläche das Ammoniakmolekül adsorbiert und stufenweise abgebaut, wodurch der benötigte Stickstoff in atomarer Form freigesetzt wird und zur Lösung im Eisen sowie zur Bildung von Eisennitrid (FexN) zur Verfügung steht. Beim Nitrocarburieren findet darüber hinaus eine gleichzeitige Anreicherung der Randschicht mit Kohlenstoff statt. Atomarer Kohlenstoff (C) diffundiert dabei in analoger Weise durch die Werkstückoberfläche in die Randschicht ein.In nitriding, for example in an ammonia-containing gas atmosphere, the surface layer is enriched with nitrogen by the ammonia (NH 3 ) contained in a reaction gas at temperatures of generally over 500 ° C under the catalytic effect of the surface of the workpieces to be nitrided breaks down into nitrogen (N) and hydrogen (H). The ammonia molecule is adsorbed and gradually degraded on the workpiece surface, releasing the required nitrogen in atomic form and making it available for solution in iron and for the formation of iron nitride (Fe x N). With nitrocarburizing, the surface layer is simultaneously enriched with carbon. Atomic carbon (C) diffuses in an analogous manner through the workpiece surface into the boundary layer.
Von besonderer Bedeutung hinsichtlich der geforderten Eigenschaften der behandelten Werkstücke ist im Allgemeinen die Randschicht, die neben hexagonalem ε-Nitrid (Fe2-3N) auch kubisch-flächenzentriertes γ'-Nitrid (Fe4N) und darüber hinaus Nitride von nitridbildenden Legierungselementen, wie zum Beispiel Chrom-, Molybdän-, Mangan-, Titan-, Niob- Wolfram-, Vanadium- oder Aluminiumnitrid, aufweisen kann.Of particular importance with regard to the required properties of the treated workpieces is the surface layer which, in addition to hexagonal ε-nitride (Fe 2-3 N), also face-centered cubic γ'-nitride (Fe 4 N) and also nitrides of nitride-forming alloy elements, such as chromium, molybdenum, manganese, titanium, niobium, tungsten, vanadium or aluminum nitride.
Vor allem bei chrom- und/oder nickellegierten Eisenwerkstoffen treten mit zunehmendem Gehalt der Legierungselemente verstärkt Passivierungserscheinungen auf, die sich zum Beispiel in einer lokal unterschiedlichen Härteannahme, der sogenannten Weichfleckigkeit, zeigen. Die Passivierung erschwert den zuvor geschilderten Stickstoffübergang aus der Gasphase in den Werkstoff mit der Folge, dass das Nitrier- bzw. Nitrocarburierergebnis nachhaltig beeinträchtigt wird.Especially with chrome and / or nickel alloyed iron materials increasing content of the alloy elements increased Passivation phenomena that occur, for example, in a local show different hardness acceptance, the so-called soft spots. The Passivation complicates the previously described nitrogen transfer from the Gas phase in the material with the result that the nitriding or Nitrocarburizing result is permanently impaired.
Im Stand der Technik sind daher eine Reihe von Verfahrensweisen bekannt, um den Oberflächenzustand von Werkstücken im Hinblick auf ein verbessertes Nitrier-bzw. Nitrocarburierergebnis zu beeinflussen. So wird beispielsweise schon in einer Artikelserie von Sidan, H: Nitrieren von rost- und säurebeständigen Stählen, Technische Rundschau (1966) 24 S. 913 ff., Technische Rundschau (1966) 28 S. 3 - 7, Technische Rundschau (1966) 42 S. 33 - 37 und 45 aufgezeigt, dass eine zufriedenstellende Nitrierung höherlegierter und damit zur Passivierung neigender Eisenwerkstoffe eine Zerstörung der Passivschicht voraussetzt. Weitere bekannte Maßnahmen sind zum Beispiel die Voroxidation oder das Oxinitrieren. Bei letzterem wird einem Reaktionsgas ein Sauerstoffträger zugesetzt, wodurch sich eine äußere Oxidation der behandelten Werkstücke ergibt. In Abhängigkeit von der Zusammensetzung des verwendeten Reaktionsgases bilden sich dabei im weiteren Verlauf des Nitrierens Fe3O4-Schichten, die für Stickstoff durchlässig sind und zu einer Zerstörung etwaiger Passivschichten führen. Die Nutzung der aktivierenden Wirkung oxidierender Gase auf die Stickstoffaufnahme höherlegierter Eisenwerkstoffe, wie etwa nichtrostende Stähle, schildern zum Beispiel Spies et al. in ihrem Artikel: Gasoxinitrieren hochlegierter Stähle, HTM 52 (1997) 6, S. 342 - 349. Dagegen schlagen Stiles et al. in ihrem Aufsatz: Beschleunigung des Gasnitrierprozesses durch eine Vorbehandlung in der reaktiven Gasphase, HTM 53 (1998) 4, S. 211 bis 219 vor, hochchromhaltige Stähle unter Sauerstoffausschluss in einer reduzierenden Atmosphäre aufzuheizen.A number of methods are therefore known in the prior art in order to determine the surface condition of workpieces with a view to an improved nitriding or. To influence nitrocarburizing result. For example, in a series of articles by Sidan, H: Nitriding of rust and acid-resistant steels, Technische Rundschau (1966) 24 pp. 913 ff., Technische Rundschau (1966) 28 pp. 3 - 7, Technische Rundschau (1966) 42 Pp. 33 - 37 and 45 show that satisfactory nitriding of higher-alloyed iron materials that tend to passivate requires destruction of the passive layer. Other known measures include preoxidation or oxynitriding. In the latter, an oxygen carrier is added to a reaction gas, which results in an external oxidation of the treated workpieces. Depending on the composition of the reaction gas used, Fe 3 O 4 layers are formed in the further course of the nitriding, which are permeable to nitrogen and lead to the destruction of any passive layers. The use of the activating effect of oxidizing gases on the nitrogen absorption of higher alloyed iron materials, such as stainless steels, is described, for example, by Spies et al. in their article: Gas oxynitriding of high-alloy steels, HTM 52 (1997) 6, pp. 342 - 349. Stiles et al. in her essay: Accelerating the gas nitriding process by pretreatment in the reactive gas phase, HTM 53 (1998) 4, pp. 211 to 219, before heating high-chromium steels with the exclusion of oxygen in a reducing atmosphere.
Nachteilig bei all diesen Maßnahmen ist allerdings, dass entweder die durch Nitrieren oder Nitrocarburieren erzeugte Nitrierschicht sich als nicht oder zumindest nicht ausreichend gleichmäßig erweist oder dass Bedingungen zur Bildung der Nitrierschicht erforderlich sind, die in technischer Hinsicht nicht oder nur mit hohem Aufwand zu realisieren sind.The disadvantage of all these measures, however, is that either the through Nitriding or nitrocarburizing produced nitriding layer as not or at least not sufficiently uniform or that conditions for Formation of the nitride layer is required, which is not technically or can only be realized with great effort.
Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren zur Wärmebehandlung metallischer Werkstücke zu schaffen, bei dem sich auch bei aus höherlegierten Eisenwerkstoffen bestehenden Werkstücken eine weitgehend gleichmäßige Nitrierschicht erzielen lässt.The invention has for its object to provide a method for the heat treatment of metallic workpieces, in which a largely uniform nitriding layer can be achieved even with workpieces consisting of higher alloyed iron materials.
Diese Aufgabe ist bei einem Verfahren der eingangs genannten Art
erfindungsgemäß durch folgende Verfahrensschritte gelöst :
Ein solches Verfahren macht sich die überraschende Erkenntnis zu Eigen, dass sich eine weitgehend gleichmäßige Nitrierschicht dann erreichen lässt, wenn die Werkstücke vor der eigentlichen Wärmebehandlung im Verfahrensschritt d, beispielshalber Nitrieren oder Nitrocarburieren, zunächst nur in einer ammoniakhaltigen Gasatmosphäre angewärmt und dann in einer zusätzlich ein Oxidationsmittel enthaltenden Gasatmosphäre auf die Behandlungstemperatur, beispielsweise die Nitriertemperatur, erwärmt und anschließend für eine gewisse Dauer bei dieser Temperatur gehalten werden mit der Folge, dass möglicherweise bei hochlegierten Werkstoffen vorhandene Passivschichten beseitigt oder so umgewandelt werden, dass eine gleichmäßige Diffusion des Stickstoffs in den Werkstoff begünstigt wird. Die Temperatur, auf die in den jeweiligen Verfahrensschritten erwärmt wird, und die Zeitdauer für die die Werkstücke in den jeweiligen Gasatmosphären gehalten werden, richten sich dabei nach der Zusammensetzung des Reaktionsgases und dem Werkstoff der zu behandelnden Werkstücke sowie dem angestrebten Behandlungserfolg.Such a procedure embraces the surprising finding that a largely uniform nitriding layer can be achieved if the Workpieces before the actual heat treatment in process step d, for example, nitriding or nitrocarburizing, initially only in one ammonia-containing gas atmosphere warmed and then in an additional one Gas atmosphere containing oxidizing agent to the treatment temperature, For example, the nitriding temperature, heated and then for a certain Duration may be kept at this temperature with the result that possibly in the case of high-alloy materials, existing passive layers are eliminated or something that be converted into a uniform diffusion of nitrogen into the Material is favored. The temperature at which in each Process steps is heated, and the length of time for which the workpieces in the respective gas atmospheres are based on the Composition of the reaction gas and the material to be treated Workpieces and the desired treatment success.
Als besonderes vorteilhaft hat sich herausgestellt, als Oxidationsmittel Luft, Kohlendioxid (CO2), Wasserdampf (H2O)D oder Stickstoffdioxid (N2O) zuzusetzen. Zweckmäßigerweise beträgt dabei das Verhältnis der Mengen von Ammoniak und dem Oxidationsmittel in der Gasatmosphäre zwischen 1 : 1 und 5 : 1, wenn Luft als Oxidationsmittel eingesetzt wird, und zwischen 1 : 0,1 und 1 : 1, wenn Kohlendioxid, Wasserdampf oder Stickstoffdioxid als Oxidationsmittel eingesetzt werden.It has been found to be particularly advantageous to add air, carbon dioxide (CO 2 ), water vapor (H 2 O) D or nitrogen dioxide (N 2 O) as the oxidizing agent. The ratio of the amounts of ammonia and the oxidizing agent in the gas atmosphere is expediently between 1: 1 and 5: 1 if air is used as the oxidizing agent and between 1: 0.1 and 1: 1 if carbon dioxide, water vapor or nitrogen dioxide Oxidizing agents are used.
Eine besonders vorteilhafte Verfahrensführung ist ferner dann gegeben, wenn die Zeitdauer beim fortgesetzten Halten der Werkstücke in einer Ammoniak bzw. Ammoniak und den kohlenstoffabgebenden Stoff enthaltenden Gasatmosphäre in Abhängigkeit von der angestrebten Dicke der anzureichernden Randschicht gewählt wird.A particularly advantageous procedure is also given when the Time period when the workpieces are kept in an ammonia or Ammonia and the carbon-donating gas atmosphere in Dependence on the desired thickness of the surface layer to be enriched is chosen.
Im Hinblick auf eine den geforderten Werkstückeigenschaften entsprechende Verfahrensführung kann es außerdem zweckdienlich sein, dass als kohlenstoffabgebender Stoff Kohlendioxid, Kohlenmonooxid oder Kohlenwasserstoffe einzeln oder als Gemisch eingesetzt werden. Mit der Erfindung wird außerdem vorgeschlagen, dass die Werkstücke in einer reduzierenden oder neutralen Gasatmosphäre, beispielsweise aus einem Endogas oder Stickstoff bestehend, oder in einem flüssigen Abschreckmedium auf Raumtemperatur abgekühlt werden, um eine in wirtschaftlicher Hinsicht günstige Verfahrensweise sicherzustellen.With regard to the workpiece properties required Procedural management may also be useful as carbon donor substance carbon dioxide, carbon monoxide or Hydrocarbons can be used individually or as a mixture. With the Invention is also proposed that the workpieces in one reducing or neutral gas atmosphere, for example from an endogas or nitrogen, or in a liquid quenching medium Room temperature can be cooled to an economically beneficial Ensure procedure.
Schließlich wird die Verwendung einer Vorrichtung zur Durchführung eines solchen Verfahrens vorgeschlagen, die aus einem Wärmebehandlungsofen mit einem beheizbaren, gasdichten Innenraum zum Nitrieren oder Nitrocarburieren von metallischen Werkstücken und mit einer Einrichtung zum dosierten Zugeben von Ammoniak, einem kohlenstoffabgebenden Stoff und einem Oxidationsmittel besteht.Finally, the use of a device for performing a proposed such a method using a heat treatment furnace a heatable, gas-tight interior for nitriding or nitrocarburizing of metallic workpieces and with a device for metered addition of ammonia, a carbon donor and an oxidizer consists.
Einzelheiten und weitere Vorteile der Gegenstände der vorliegenden Erfindung ergeben sich aus der nachfolgenden Beschreibung eines bevorzugten Ausführungsbeispieles. In der zugehörigen Zeichnung veranschaulichen im Einzelnen:
- Fig. 1
- ein das Gefüge einer Werkstückprobe nach einer konventionellen Nitrierbehandlung zeigendes Schliffbild und
- Fig. 2
- ein Fig. 1 entsprechendes Schliffbild einer nach dem erfindungsgemäßen Verfahren behandelten Werkstückprobe.
- Fig. 1
- a micrograph showing the structure of a workpiece sample after a conventional nitriding treatment and
- Fig. 2
- a micrograph corresponding to FIG. 1 of a workpiece sample treated by the method according to the invention.
In den Fig. 1 und 2 ist das sich nach metallographischer Prüfung bei 200facher Vergrößerung ergebende Ergebnis zweier nitrierter Werkstückproben dargestellt. Zur vergleichenden Analyse der Gleichmäßigkeit der erzeugten Nitrierschichten wurden die beiden identischen Werkstückproben der Stahlsorte X 30 Cr 13 (Werkstoff-Nr. 1.4028) in einer ammoniakhaltigen Gasatmosphäre eines Kammerofens, dessen Ofenraum zuvor bei Raumtemperatur mit einem Endogas gespült wurde, bei einer Nitriertemperatur von ca. 580 °C nitriert.1 and 2, this is 200 times after metallographic examination Result of the enlargement of two nitrided workpiece samples. For a comparative analysis of the uniformity of the nitriding layers produced the two identical workpiece samples of steel grade X 30 Cr 13 (Material no. 1.4028) in an ammonia-containing gas atmosphere Chamber furnace, the furnace chamber of which was previously at room temperature with an endogas was rinsed, nitrided at a nitriding temperature of approx. 580 ° C.
Die in Fig. 1 gezeigte erste Werkstückprobe wurde hierbei zunächst in einer endogashaltigen Gasatmosphäre auf eine Temperatur von ca. 450 °C vorgewärmt und anschließend in einem aus 50 Vol.-% Ammoniak (NH3) und 50 Vol.-% Endogas bestehenden Reaktionsgas auf die Nitriertemperatur von ca. 580 °C erwärmt. Nach ca. 240 min, während denen die Werkstückprobe bei dieser Temperatur der Gasatmosphäre ausgesetzt war, wurde die Werkstückprobe in einer endogashaltigen Gasatmosphäre auf Raumtemperatur abgekühlt.The first workpiece sample shown in FIG. 1 was preheated to a temperature of approximately 450 ° C. in an endogas-containing gas atmosphere and then in a reaction gas consisting of 50 vol.% Ammonia (NH 3 ) and 50 vol.% Endogas the nitriding temperature of approx. 580 ° C warmed. After approximately 240 minutes, during which the workpiece sample was exposed to the gas atmosphere at this temperature, the workpiece sample was cooled to room temperature in an endogenous gas atmosphere.
Im Vergleich hierzu wurde die in Fig. 2 dargestellte zweite Werkstückprobe zunächst in einer ammoniakhaltigen Gasatmosphäre auf eine Temperatur von ca. 450 °C vorgewärmt und anschließend in einem ammoniakhaltigen Reaktionsgas, dem Luft als Oxidationsmittel im Verhältnis 3,5 (Ammoniak) : 1 (Luft) zugesetzt war, auf die Nitriertemperatur von ca. 580 °C erwärmt. Bei dieser Temperatur und in dieser Gasatmosphäre wurde die Werkstückprobe sodann für eine Dauer von ca. 1,5 h gehalten. Danach wurde die Gasatmosphäre ausgetauscht und die Werkstückprobe bei 580 °C einem Reaktionsgas mit der Zusammensetzung 50 Vol.-% Ammoniak (NH3) und 50 Vol.-% Endogas für ca. 4 h ausgesetzt, um die angestrebte Nitriertiefe von ca. 80 µm zu erreichen. Zum Schluss wurde die zweite Werkstückprobe dann ebenfalls in einer endogashaltigen Gasatmosphäre auf Raumtemperatur abgekühlt.In comparison, the second workpiece sample shown in Fig. 2 was first preheated in an ammonia-containing gas atmosphere to a temperature of about 450 ° C and then in an ammonia-containing reaction gas, the air as an oxidizing agent in a ratio of 3.5 (ammonia): 1 (air ) was added, heated to the nitriding temperature of approx. 580 ° C. The workpiece sample was then held at this temperature and in this gas atmosphere for a period of about 1.5 hours. The gas atmosphere was then exchanged and the workpiece sample was exposed at 580 ° C. to a reaction gas with the composition 50% by volume of ammonia (NH 3 ) and 50% by volume of endogas for about 4 hours in order to achieve the desired nitriding depth of about 80 µm to reach. Finally, the second workpiece sample was also cooled to room temperature in an endogas-containing gas atmosphere.
Die Gegenüberstellung der in der Zeichnung gezeigten Schliffbilder zeigt, dass das in Fig. 1 dargestellte, durch herkömmliches Nitrieren erzeugte Gefüge der ersten Werkstückprobe im Bereich von 0 µm bis 40 µm Abstand vom Rand eine ungleichmäßige Nitrierschicht aufweist, während die nach der letztgeschilderten Verfahrensweise erzeugte Nitrierschicht der zweiten Werkstückprobe weitgehend gleichmäßig ausgebildet ist.The comparison of the micrographs shown in the drawing shows that the 1, structure of the first produced by conventional nitriding Workpiece sample in the range from 0 µm to 40 µm from the edge uneven nitriding layer, while that after the last Methodically generated nitriding layer of the second workpiece sample is evenly formed.
Mithin lassen sich im zuletzt dargestellten Fall bei höherlegierten Eisenwerkstoffen, etwa nichtrostende Stähle, deren hohe Korrosionsbeständigkeit untrennbar mit einer Oberflächenpassivierung verbunden ist, auf verhältnismäßig einfache Art und Weise bessere Behandlungsergebnisse erzielen.Thus, in the last case, higher alloys can be used Iron materials, such as stainless steels, their high corrosion resistance is inextricably linked to surface passivation, on proportionate achieve better treatment results in a simple way.
Claims (7)
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Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP00102359A EP1122331B1 (en) | 2000-02-04 | 2000-02-04 | Process of nitriding and/or carbonitriding of high-alloyed steel |
DE50001540T DE50001540D1 (en) | 2000-02-04 | 2000-02-04 | Process for nitriding and / or nitrocarburizing higher alloy steels |
AT00102359T ATE235581T1 (en) | 2000-02-04 | 2000-02-04 | METHOD FOR NITRIDING AND/OR NITROCARBURIZING HIGHER ALLOY STEEL |
US09/562,695 US6328819B1 (en) | 2000-02-04 | 2000-04-28 | Method and use of an apparatus for the thermal treatment, in particular nitriding treatment, of metal workpieces |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP00102359A EP1122331B1 (en) | 2000-02-04 | 2000-02-04 | Process of nitriding and/or carbonitriding of high-alloyed steel |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1122331A1 true EP1122331A1 (en) | 2001-08-08 |
EP1122331B1 EP1122331B1 (en) | 2003-03-26 |
Family
ID=8167773
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP00102359A Expired - Lifetime EP1122331B1 (en) | 2000-02-04 | 2000-02-04 | Process of nitriding and/or carbonitriding of high-alloyed steel |
Country Status (4)
Country | Link |
---|---|
US (1) | US6328819B1 (en) |
EP (1) | EP1122331B1 (en) |
AT (1) | ATE235581T1 (en) |
DE (1) | DE50001540D1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014002120A1 (en) * | 2012-06-26 | 2014-01-03 | Cavina Fulvio Fabrizio | Process and plant for the anti-oxidising surface treatment of steel parts |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
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US6929757B2 (en) * | 2003-08-25 | 2005-08-16 | General Motors Corporation | Oxidation-resistant magnetorheological fluid |
US7622197B2 (en) * | 2006-11-20 | 2009-11-24 | Ferroxy-Aled, Llc | Seasoned ferrous cookware |
ITMI20110366A1 (en) * | 2011-03-10 | 2012-09-11 | Sol Spa | PROCEDURE FOR STEEL TREATMENT. |
RU2519356C2 (en) * | 2012-05-24 | 2014-06-10 | Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Московский автомобильно-дорожный государственный технический университет (МАДИ)" | Method of cyclic gas nitration of steel dies for hot forming |
DE102013226090A1 (en) | 2013-12-16 | 2015-06-18 | Robert Bosch Gmbh | Process for gas nitrocarburizing |
DE102013226091A1 (en) | 2013-12-16 | 2015-06-18 | Robert Bosch Gmbh | Cylinder drum of a hydrostatic axial piston machine with a wear protection layer |
DE102016221891A1 (en) | 2016-11-08 | 2018-05-09 | Robert Bosch Gmbh | Process for the heat treatment of a high-alloy steel workpiece |
JP6930738B2 (en) * | 2018-08-03 | 2021-09-01 | 錦見鋳造株式会社 | How to make cookware |
CN114174550A (en) | 2019-08-23 | 2022-03-11 | 医乐世医疗技术皮诺公司 | Hardfacing for dental implants |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DD119822A1 (en) * | 1975-06-20 | 1976-05-12 | ||
US4131492A (en) * | 1976-04-08 | 1978-12-26 | Nissan Motor Company, Ltd. | Steel article having a nitrided and partly oxidized surface and method for producing same |
US4496401A (en) * | 1981-10-15 | 1985-01-29 | Lucas Industries | Corrosion resistant steel components and method of manufacture thereof |
GB2153855A (en) * | 1984-01-27 | 1985-08-29 | Procedyne Corp | Stainless steel case hardening process |
EP0655512A1 (en) * | 1993-11-18 | 1995-05-31 | Ipsen Industries International Gesellschaft Mit Beschränkter Haftung | Method for producing unitary oxidic layers on metallic substrates and apparatus for carrying out the process |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1351234A (en) * | 1970-07-21 | 1974-04-24 | Nissan Motor | Process for forming a soft nitride layer in a metal surface |
FR2524006B1 (en) * | 1982-03-23 | 1985-10-11 | Air Liquide | PROCESS FOR THE SURFACE CURING OF METAL PARTS |
US5037491A (en) * | 1986-02-28 | 1991-08-06 | Fox Patrick L | Shallow case hardening and corrosion inhibition process |
DE3718240C1 (en) * | 1987-05-30 | 1988-01-14 | Ewald Schwing | Process for the heat treatment of metallic workpieces in a gas-flowed fluidized bed |
-
2000
- 2000-02-04 EP EP00102359A patent/EP1122331B1/en not_active Expired - Lifetime
- 2000-02-04 DE DE50001540T patent/DE50001540D1/en not_active Expired - Lifetime
- 2000-02-04 AT AT00102359T patent/ATE235581T1/en active
- 2000-04-28 US US09/562,695 patent/US6328819B1/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DD119822A1 (en) * | 1975-06-20 | 1976-05-12 | ||
US4131492A (en) * | 1976-04-08 | 1978-12-26 | Nissan Motor Company, Ltd. | Steel article having a nitrided and partly oxidized surface and method for producing same |
US4496401A (en) * | 1981-10-15 | 1985-01-29 | Lucas Industries | Corrosion resistant steel components and method of manufacture thereof |
GB2153855A (en) * | 1984-01-27 | 1985-08-29 | Procedyne Corp | Stainless steel case hardening process |
EP0655512A1 (en) * | 1993-11-18 | 1995-05-31 | Ipsen Industries International Gesellschaft Mit Beschränkter Haftung | Method for producing unitary oxidic layers on metallic substrates and apparatus for carrying out the process |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014002120A1 (en) * | 2012-06-26 | 2014-01-03 | Cavina Fulvio Fabrizio | Process and plant for the anti-oxidising surface treatment of steel parts |
Also Published As
Publication number | Publication date |
---|---|
US6328819B1 (en) | 2001-12-11 |
ATE235581T1 (en) | 2003-04-15 |
EP1122331B1 (en) | 2003-03-26 |
DE50001540D1 (en) | 2003-04-30 |
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