EP2881493B1 - Process for the nitrocarburization of a deep drawn article or a bent pressed article made of austenitic stainless steel - Google Patents

Process for the nitrocarburization of a deep drawn article or a bent pressed article made of austenitic stainless steel Download PDF

Info

Publication number
EP2881493B1
EP2881493B1 EP13196075.9A EP13196075A EP2881493B1 EP 2881493 B1 EP2881493 B1 EP 2881493B1 EP 13196075 A EP13196075 A EP 13196075A EP 2881493 B1 EP2881493 B1 EP 2881493B1
Authority
EP
European Patent Office
Prior art keywords
article
gas mixture
process step
nitrogen
rich phase
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.)
Active
Application number
EP13196075.9A
Other languages
German (de)
French (fr)
Other versions
EP2881493A1 (en
Inventor
Cord-Hinrich Bremer
Rolf Lange
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.)
Hubert Stueken & Co KG GmbH
Original Assignee
Hubert Stueken & Co KG GmbH
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.)
Filing date
Publication date
Application filed by Hubert Stueken & Co KG GmbH filed Critical Hubert Stueken & Co KG GmbH
Priority to PL13196075T priority Critical patent/PL2881493T3/en
Priority to EP13196075.9A priority patent/EP2881493B1/en
Priority to US14/557,592 priority patent/US9738964B2/en
Priority to CN201410734836.4A priority patent/CN104694873B/en
Publication of EP2881493A1 publication Critical patent/EP2881493A1/en
Application granted granted Critical
Publication of EP2881493B1 publication Critical patent/EP2881493B1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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
    • C23C8/32—Carbo-nitriding of ferrous surfaces
    • 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
    • C23C8/02—Pretreatment of the material to be coated
    • 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
    • C23C8/10—Oxidising
    • 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
    • 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
    • C23C8/80—After-treatment

Definitions

  • the invention relates to a process for nitrocarburizing a thermoformed article or a stamped article made of austenitic stainless steel with a wall thickness which is at least partially suitable for such articles.
  • Nitrocarburizing is a process for surface hardening of metals, in which the metal to be hardened is enriched in its edge region with carbon and nitrogen. It has long been established in the art, which is why it does not require a separate documentary evidence at this point.
  • filigree articles are used in the most diverse areas of technology, such as bearing covers in gearboxes, valve seats in ABS systems or as sample carriers for hazardous substances in high-precision measurements where they are exposed to extreme mechanical, thermal and chemical stresses.
  • the demand for high hardness corrosion resistant materials is therefore correspondingly high.
  • edge layers produced in this way do not form a peripherally closed structure. Rather, these edge layers are highly rugged and have a plurality of edge layer penetrating channels in which there is direct contact between the environment and the uncured core portion of the thermoformed article. Likewise, the edge region produced in this way has numerous defects and coarse-grained particles. Due to this heterogeneous design, both the hardness of the surface layer and its corrosion properties are subject to such high fluctuations that an industrial application is possible only to a very limited extent.
  • the EP 0 588 458 discloses in this context a method for nitriding an austenitic metal.
  • the metal is exposed to a fluorine-containing gas.
  • Fluorine-containing gases are highly corrosive due to their reactivity and, as a result, aggressively affect the surface of the metal. While with it caused surface removal is even desirable for articles with high wall thickness due to a corresponding material wealth, it can not be compensated for thin-walled thermoforming articles or stamped and bent articles and leads in part to the irreversible destruction of the surface of the article.
  • thermoforming and stamping bending articles With the invention, a method with mild conditions is proposed in an advantageous manner, which are tailored to the specifics of thin-walled thermoforming and stamping bending articles.
  • the article is introduced into an oven for carrying out the method. It has been shown that in particular oxygen and water residues interfere with the surface hardening. To exclude these disturbing factors, the article is heated to a temperature which is above the boiling point of water. Essential here is a temperature of 100 ° C to 140 ° C, more preferably 120 ° C.
  • the oxygen-containing atmosphere in the furnace is replaced in accordance with the invention by a first gas mixture.
  • the furnace therefore advantageously has gas inlets and gas outlets.
  • the furnace may be provided to flood the furnace with an inert gas before the introduction of the first gas mixture.
  • the oxygen displacement is accelerated in an advantageous manner and a possibly existing hazard potential, resulting from the contact of the oxygen-containing normal atmosphere with the first gas mixture, lowered.
  • the inert gas it is preferable to use known chemically unreactive gases such as, in particular, nitrogen or argon.
  • Stainless steels include, among others, chromium as an alloying constituent. Upon contact with atmospheric oxygen, a passivating and corrosion-resistant chromium (III) oxide layer is formed on the surface of the material.
  • the first gas mixture has reducing properties in order to avoid further oxidation of the chromium.
  • this gas mixture already initiated the depassivation of the surface.
  • the first gas mixture is H 2 and N 2 . It has been found that this gas mixture, in particular in conjunction with the mild temperature of the first process step, exerts a particularly mild and advantageous effect on the chromium oxide layer without adversely altering the morphology of the surface of the filigree steel articles.
  • the oxygen concentration is measured continuously or at intervals by means of a sensor.
  • a control unit connected to the sensor checks the actual value here continuously or at intervals with a freely selectable desired value and releases the oven in the case of an identity between actual and desired value for a second method step.
  • the inventive method is thereby greatly simplified in an advantageous manner and minimizes in this way possible user-side sources of error.
  • a second method step in which the thermoforming or stamped bent article is heated to the target temperature, the second temperature, for the surface hardening.
  • the second temperature is chosen so that it is well below the recrystallization temperature of strongly cold-worked iron alloys (680 ° C). A possible change in the morphology of the surface is thereby effectively prevented, whereby the formation of a homogeneous surface layer is promoted.
  • the second temperature is 450 ° C to 550 ° C, and more preferably 500 ° C.
  • the heating phase serves in particular the careful and complete depassivation of the chromium oxide layer.
  • the heating rate in a certain temperature range between 0.5 and 1 ° C / min, more preferably between 0.5 and 0.7 ° C / min and more preferably 0.5 ° C / min.
  • the temperature range in which this low heating rate is selected is preferably 420 ° C to 550 ° C, more preferably 450 ° C to 500 ° C, and most preferably 480 ° C to 500 ° C.
  • the first gas mixture is replaced by a second gas mixture in the second method step. It has been found that mild depassivation of the thin-walled deep-drawn parts during the heating phase to the second temperature by a gas mixture consisting of a hydrogen-containing gas, a nitrogen-containing gas and a carbon-containing gas. Particularly in connection with the low heating rate, a particularly slow and therefore mild and readily controllable depassivation of the chromium oxide layer can be achieved.
  • the article is treated with additives which selectively or completely dissolve the passive layer.
  • additives which selectively or completely dissolve the passive layer.
  • it means salt compounds and / or organic substances and acid generators, which are applied in solid or liquid form to the product or in the oven.
  • the application is preferably carried out either before the article is placed in the oven or during the second process step.
  • solid and / or liquids are used, which in Compound with the reaction gases form acidic reaction products that would give a pH ⁇ 7 when introduced into water.
  • the application of the substances directly on or in the article surface has proved to be particularly advantageous. As a result, local depassivation processes, which initiate and promote uniform depassivation earlier, occur even at low temperatures.
  • carbon oxides saturated and unsaturated hydrocarbons
  • Particularly preferred here is the use of carbon oxides, in particular carbon monoxide.
  • ammonia and nitrogen oxides can be added to the second gas mixture. Particularly preferred here is the use of ammonia.
  • the temperature is measured continuously or at intervals by means of a sensor.
  • the control unit connected to the sensor checks the actual value here continuously or at intervals with a freely selectable setpoint value for the second temperature and releases the oven in the case of an identity between the actual and setpoint values for a third method step.
  • the inventive method is thereby greatly simplified in an advantageous manner and minimizes in this way possible user-side sources of error.
  • a third method step is provided in which the article is kept constant at the second temperature.
  • the third process step is in this context the nitrocarburizing of the thin-walled article and leads by carburizing and nitriding of the edge region of the steel article to form a hardened surface layer.
  • the second temperature advantageously allows a careful construction of the hardened surface layer.
  • the diffusion of the carbon and nitrogen in the edge region of the deep-drawn part takes place slowly at these temperatures, is therefore well controlled and causes the Structure of a homogeneous surface layer.
  • the method according to the invention promotes, in particular, the formation of a boundary layer which consists of a carbon-rich phase closer to the core and an outer nitrogen-rich phase. Too high a temperature is to be avoided in any case, as it comes to the formation of irregular layers and the formation of carbide and / or nitride particles due to the high diffusion rate and the high kinetic energy of the molecules involved.
  • the second gas mixture is used for nitrocarburizing the thermoforming article.
  • the second gas mixture causes, especially in conjunction with the mild temperature, a particularly gentle and controlled construction of the boundary layer according to the invention, formed from a carbon-rich and a nitrogen-rich phase.
  • ammonia promotes the formation of a particularly homogeneous nitrogen-rich phase.
  • the individual concentrations of the gas components are measured continuously or at intervals by means of respective sensors.
  • the control unit connected to the sensors checks the respective actual values continuously or at intervals with freely selectable desired values for the respective concentration of the gas component and compensates for changes within a fault tolerance continuously or at intervals.
  • the process control is advantageously simplified and allows the provision of constant process conditions, which is for the construction of a homogeneous carbon-rich surface layer of crucial importance.
  • the layer thickness of the carbon-rich surface layer can be adjusted over the gassing time.
  • a period of 2 to 20 hours is required to generate a 5 to 35 .mu.m thick edge layer.
  • control unit which provides for Time recording on a corresponding device has, after an arbitrary Nitrocarbur istszeit a free oven for the fourth step.
  • the inventive method is thereby greatly simplified in an advantageous manner and minimizes in this way possible user-side sources of error.
  • a fourth method step is provided in which the deep-drawn part is cooled to a third temperature. It is provided here, the deep-drawn part to a temperature of 50 ° C to 80 ° C and more preferably cool to 60 ° C.
  • the choice of atmosphere in the cooled is crucial for the formation of a homogeneous surface layer. It is therefore provided according to the invention to replace the second gas mixture by a third gas mixture.
  • the choice of a slightly reducing gas mixture is considered advantageous.
  • the third gas mixture of H 2 and N 2 .
  • the composition of the third gas mixture advantageously consists of 5% to 25% H 2 and 75% to 95% N 2 , more preferably 5% to 10% H 2 and 90% to 95% N 2 and especially preferably 5% H 2 and 95% N 2 . It has been found that the inventive cooling of the thin-walled deep-drawn part effectively prevents escape of both the carbon and the nitrogen from the hardened surface layer and promotes the inclusion of both components in dissolved form.
  • the invention relates to a nitrocarburized thermoforming article made of austenitic stainless steel with a standard for thermoforming articles, at least partially low wall thickness.
  • thermoformed article with thin wall thickness By means of the method according to the invention, it is now possible for the first time to harden a thermoformed article with thin wall thickness in an industrially reproducible manner and in excellent quality.
  • the deep-drawing article according to the invention has a soft or depending on the cold deformation cold-strengthened elastic core and a hard edge layer on.
  • the edge layer is free of defects and / or particles, circumferentially completely closed and has a substantially planar surface.
  • the thin-walled thermoforming article according to the invention has mechanical properties of unprecedented quality.
  • the corrosion and abrasion resistance of the thermoforming article in the inventive way better than that of the starting material.
  • the surface layer consists of an outer nitrogen-rich phase and a carbon-rich phase located between the core and the nitrogen-rich phase.
  • the carbon-rich phase in this case has a hardness of 700 to 1000 HV0.025 and a layer thickness of 2.5 to 15 microns.
  • the nitrogen-rich phase however, has a hardness of 1000 to 1400 HV0.025 and a layer thickness of 2.5 to 20 microns.
  • a hardness gradient is advantageously formed from the soft core to the harder carbon-rich phase to the even harder nitrogen-rich phase.
  • the material is thereby advantageously flexible in its core region and cured in its edge region. Characterized in that a two-phase edge layer is formed with different hardness, also the edge layer has an increased flexibility with simultaneous enormous hardness.

Description

Die Erfindung betrifft ein Verfahren zur Nitrocarburierung eines Tiefziehartikels oder eines Stanzbiegetartikels aus austenitischem nichtrostendem Edelstahl mit einer wenigstens bereichsweise für solche Artikel üblichen geringen Wandstärke.The invention relates to a process for nitrocarburizing a thermoformed article or a stamped article made of austenitic stainless steel with a wall thickness which is at least partially suitable for such articles.

Die Nitrocarburierung ist ein Verfahren zur Randschichthärtung von Metallen, bei dem das zu härtende Metall in seinem Randbereich mit Kohlenstoff und Stickstoff angereichert wird. Es ist im Stand der Technik seit langem etabliert, weshalb es eines gesonderten druckschriftlichen Nachweises an dieser Stelle nicht bedarf.Nitrocarburizing is a process for surface hardening of metals, in which the metal to be hardened is enriched in its edge region with carbon and nitrogen. It has long been established in the art, which is why it does not require a separate documentary evidence at this point.

Bei Tiefziehtartikeln und Stanzbiegeteilen im Sinne der Erfindung liegen übliche geringe Wandstärken unterhalb von 2000 µm. Solche Edelstahlartikel werden aus sehr dünnen Blechen durch Zugdruckumformen oder Stanzbiegen hergestellt und nehmen mitunter sehr filigrane Strukturen an. Je nach verwendetem Verfahren können Artikel mit variierender oder konstanter Wandstärke hergestellt werden, wodurch diese dann wenigstens bereichsweise oder in Gänze eine Wandstärke von weniger als 2000 µm aufweisen.In the case of thermoformed articles and stamped and bent parts in the sense of the invention, conventional low wall thicknesses are below 2000 μm. Such stainless steel articles are made of very thin sheets by tensile or compression bending and sometimes take on very filigree structures. Depending on the method used, articles with varying or constant wall thickness can be produced, whereby they then have a wall thickness of less than 2000 μm, at least in regions or as a whole.

Diese filigranen Artikel werden in den unterschiedlichsten Bereichen der Technik wie z.B. als Lagerabdeckung in Getrieben, Ventilsitze in ABS-Systemen oder als Probenträger für Gefahrstoffe bei Hochpräzisionsmessungen eingesetzt und sind dort extremen mechanischen, thermischen und chemischen Belastungen ausgesetzt. Der Bedarf an korrosionsbeständigen Materialien mit hoher Härte ist daher dementsprechend hoch.These filigree articles are used in the most diverse areas of technology, such as bearing covers in gearboxes, valve seats in ABS systems or as sample carriers for hazardous substances in high-precision measurements where they are exposed to extreme mechanical, thermal and chemical stresses. The demand for high hardness corrosion resistant materials is therefore correspondingly high.

Die Qualität solcher gehärteten Artikel, insbesondere bei Teilen, die ein hohes Verhältnis von Länge zu Durchmesser besitzen (Aspektverhältnis), lässt allerdings bislang sowohl hinsichtlich der mechanischen Beständigkeit als auch der Korrosionsbeständigkeit zu wünschen übrig. Wendet man aus dem Stand der Technik bekannte und etablierte Verfahren zur Randschichthärtung auf Artikel mit sehr dünner Wandstärke an, so lassen sich keine industriell reproduzierbaren und den Qualitätsansprüchen genügende Randschichten herstellen.However, the quality of such cured articles, especially parts having a high length to diameter ratio (aspect ratio), leaves much to be desired in terms of both mechanical resistance and corrosion resistance. If one applies known and established methods for surface hardening on articles with very thin wall thickness from the prior art, then no industrially reproducible and quality claims sufficient edge layers can be produced.

Elektronenmikroskopische und metallographische Untersuchungen von Querschnitten nitrocarburierter Tiefziehartikel haben ergeben, dass auf diese Weise hergestellte Randschichten keine umlaufend geschlossene Struktur ausbilden. Vielmehr sind diese Randschichten stark zerklüftet und weisen eine Vielzahl von die Randschicht durchdringende Kanäle auf, in denen ein direkter Kontakt zwischen der Umgebung und dem ungehärteten Kernbereich des Tiefziehartikels besteht. Ebenso weist der auf diese Art hergestellte Randbereich zahlreiche Defektstellen und grobkörnige Partikel auf. Aufgrund dieser heterogenen Ausbildung unterliegen sowohl die Härte der Randschicht als auch deren Korrosionseigenschaften so hohen Schwankungen, dass eine industrielle Anwendung nur stark eingeschränkt möglich ist.Electron-microscopic and metallographic investigations of cross-sections of nitrocarburized thermoforming articles have shown that edge layers produced in this way do not form a peripherally closed structure. Rather, these edge layers are highly rugged and have a plurality of edge layer penetrating channels in which there is direct contact between the environment and the uncured core portion of the thermoformed article. Likewise, the edge region produced in this way has numerous defects and coarse-grained particles. Due to this heterogeneous design, both the hardness of the surface layer and its corrosion properties are subject to such high fluctuations that an industrial application is possible only to a very limited extent.

Der Grund für diese Ergebnisse ist vor allem in den zum Teil extremen Behandlungsbedingungen der etablierten Verfahren zu suchen.The reason for these results is to be found above all in the sometimes extreme treatment conditions of the established methods.

So zeigt Die DE 44 42 382 C1 ein Verfahren zur Nitrocarburierung eines nichtrostenden Stahlartikels, bei dem besagter Stahlartikel in einem Schmelzalkalibad behandelt wird. Eine solch aggressive Art der Behandlung führt bei filigranen Artikeln im Sinne der Erfindung aufgrund der geringen Wandstärke zu zum Teil erheblichen Korrosionserscheinungen, was eine in hohem Maße inhomogene Randschicht zur Folge hat. Darüber hinaus hat es sich gezeigt, dass Flüssigkeitsbehandlungen bei filigranen Tiefziehartikeln aufgrund einer unvollständigen Oberflächenbenetzung zu unbefriedigenden Ergebnissen führen.So shows the DE 44 42 382 C1 a method of nitrocarburizing a stainless steel article, wherein said steel article is treated in a melt alkali bath. Such an aggressive type of treatment leads to filigree articles in the context of the invention due to the small wall thickness sometimes severe corrosion phenomena, which has a highly inhomogeneous edge layer result. In addition, it has been found that fluid treatments in filigree thermoformed articles result in unsatisfactory results due to incomplete surface wetting.

Die EP 0 588 458 offenbart in diesem Zusammenhang ein Verfahren zur Nitridierung eines austenitischen Metalls. Hier wird das Metall mit einem fluorhaltigen Gas beaufschlagt. Fluorhaltige Gase sind aufgrund ihrer Reaktionsfreudigkeit hochkorrosiv und wirken infolgedessen aggressiv auf die Oberfläche des Metalls ein. Während der damit bewirkte Oberflächenabtrag bei Artikeln mit hoher Wandstärke infolge eines entsprechenden Materialreichtums sogar erwünscht ist, kann er bei dünnwandigen Tiefziehartikeln oder Stanzbiegeartikeln nicht kompensiert werden und führt teilweise zur irreversiblen Zerstörung der Oberfläche des Artikels. Darüber hinaus stellen die dort eingesetzten Gase aufgrund ihrer hohen Giftigkeit, ihrer hohen Korrosivität und ihrer stark umweltgefährdenden Eigenschaften enorme Ansprüche an den zu verwendenden Reaktor, die Lagerung und die Arbeitssicherheit.The EP 0 588 458 discloses in this context a method for nitriding an austenitic metal. Here, the metal is exposed to a fluorine-containing gas. Fluorine-containing gases are highly corrosive due to their reactivity and, as a result, aggressively affect the surface of the metal. While with it caused surface removal is even desirable for articles with high wall thickness due to a corresponding material wealth, it can not be compensated for thin-walled thermoforming articles or stamped and bent articles and leads in part to the irreversible destruction of the surface of the article. In addition, because of their high toxicity, their high corrosiveness and their highly environmentally hazardous properties, the gases used there place enormous demands on the reactor to be used, storage and occupational safety.

Es ist daher die Aufgabe der Erfindung ein wirksames Verfahren zur Nitrocarburierung von dünnwandigen tiefgezogenen oder stanzgebogenen Edelstahlartikeln bereitzustellen.It is therefore the object of the invention to provide an effective method for nitrocarburizing thin-walled deep-drawn or stamped bent stainless steel articles.

Zur Lösung dieser Aufgabe wird eine Erfindung mit den Merkmalen gemäß Anspruch 1 vorgeschlagen. Weitere Vorteile und Merkmale ergeben sich aus den Unteransprüchen.To solve this problem, an invention with the features of claim 1 is proposed. Further advantages and features emerge from the subclaims.

Mit der Erfindung wird in vorteilhafterweise ein Verfahren mit milden Bedingungen vorgeschlagen, welche auf die Besonderheiten von dünnwandigen Tiefzieh- und Stanzbiegeartikeln abgestimmt sind.With the invention, a method with mild conditions is proposed in an advantageous manner, which are tailored to the specifics of thin-walled thermoforming and stamping bending articles.

In erfindungsgemäßer Weise wird der Artikel zur Durchführung des Verfahrens in einen Ofen eingebracht. Es hat sich gezeigt, dass insbesondere Sauerstoff- und Wasserreste die Randschichthärtung stören. Zum Ausschluss dieser Störfaktoren wird der Artikel auf eine Temperatur erwärmt, die oberhalb des Siedepunktes von Wasser liegt. Wesentlich ist hierbei eine Temperatur von 100 °C bis 140 °C, besonders bevorzugt 120 °C.In accordance with the invention, the article is introduced into an oven for carrying out the method. It has been shown that in particular oxygen and water residues interfere with the surface hardening. To exclude these disturbing factors, the article is heated to a temperature which is above the boiling point of water. Essential here is a temperature of 100 ° C to 140 ° C, more preferably 120 ° C.

Darüber hinaus wird die sich im Ofen befindliche sauerstoffhaltige Atmosphäre in erfindungsgemäßer Weise durch ein erstes Gasgemisch ersetzt. Der Ofen verfügt daher in vorteilhafterweise über Gaseinlässe und Gasauslässe.In addition, the oxygen-containing atmosphere in the furnace is replaced in accordance with the invention by a first gas mixture. The furnace therefore advantageously has gas inlets and gas outlets.

Gemäß einer bevorzugten Verfahrensführung kann es vorgesehen sein, den Ofen vor der Einleitung des ersten Gasgemisches mit einem Inertgas zu fluten. Die Sauerstoffverdrängung wird hierbei in vorteilhafter Weise beschleunigt und ein möglicherweise bestehendes Gefahrenpotential, resultierend aus dem Kontakt der sauerstoffhaltigen Normalatmosphäre mit dem ersten Gasgemisch, gesenkt. Als Inertgas werden bevorzugterweise bekannte chemisch unreaktive Gase wie insbesondere Stickstoff oder Argon verwendet.According to a preferred process control, it may be provided to flood the furnace with an inert gas before the introduction of the first gas mixture. In this case, the oxygen displacement is accelerated in an advantageous manner and a possibly existing hazard potential, resulting from the contact of the oxygen-containing normal atmosphere with the first gas mixture, lowered. As the inert gas, it is preferable to use known chemically unreactive gases such as, in particular, nitrogen or argon.

Nichtrostende Edelstähle beinhalten unter anderem Chrom als Legierungsbestandteil. An der Materialoberfläche bildet sich durch den Kontakt mit Luftsauerstoff eine passivierende und korrosionsbeständige Chrom-(III)-Oxidschicht aus.Stainless steels include, among others, chromium as an alloying constituent. Upon contact with atmospheric oxygen, a passivating and corrosion-resistant chromium (III) oxide layer is formed on the surface of the material.

Bei Verfahren zur Randschichthärtung, insbesondere der Nitrocarburierung, ist es von enormer Bedeutung, diese passivierende Chrom-Oxidschicht zu entfernen bzw. zu depassivieren, um eine homogene Diffusion des Kohlenstoffs und des Stickstoffs in den Randbereich des Edelstahls zu ermöglichen. Ist dies durch mangelnde Depassivierung nicht gewährleistet, ist die Eindiffusion in Bereichen mit intakter Chrom-Oxidschicht gehemmt und es kommt in der Konsequenz zu einer inhomogenen Härteverteilung der resultierenden Randschicht. Darüber hinaus fördert eine mangelnde Depassivierung in Bereichen mit intakter Chrom-Oxidschicht die Ausbildung von Defektstellen im Randbereich. Diese Defektstellen führen in der Konsequenz zu einer unerwünschten, verminderten Verschleißbeständigkeit und beeinträchtigen die Korrosionsbeständigkeit des Stahls.In the case of surface hardening processes, in particular nitrocarburization, it is of enormous importance to remove or depassivate this passivating chromium oxide layer in order to allow homogeneous diffusion of the carbon and nitrogen into the edge region of the stainless steel. If this is not ensured by a lack of depassivation, the diffusion into regions with an intact chromium oxide layer is inhibited and, as a consequence, an inhomogeneous hardness distribution of the resulting surface layer occurs. In addition, a lack of depassivation in areas with intact chromium oxide layer promotes the formation of defects in the edge area. As a consequence, these defects result in undesirable, reduced wear resistance and impair the corrosion resistance of the steel.

Das erste Gasgemisch hat daher gemäß einem Merkmal der Erfindung reduzierende Eigenschaften, um eine weitere Oxidation des Chroms zu vermeiden. Darüber hinaus wird mit dieser Gasmischung bereits die Depassivierung der Oberfläche eingeleitet. Gemäß einem Merkmal der Erfindung besteht das erste Gasgemisch aus H2 und N2. Es hat sich gezeigt, dass dieses Gasgemisch insbesondere in Verbindung mit der milden Temperatur des ersten Verfahrensschrittes eine besonders milde und vorteilhafte Wirkung auf die Chromoxidschicht ausübt, ohne die Morphologie der Oberfläche der filigranen Stahlartikel nachteilig zu verändern.Thus, according to one feature of the invention, the first gas mixture has reducing properties in order to avoid further oxidation of the chromium. In addition, this gas mixture already initiated the depassivation of the surface. According to one feature of the invention, the first gas mixture is H 2 and N 2 . It has been found that this gas mixture, in particular in conjunction with the mild temperature of the first process step, exerts a particularly mild and advantageous effect on the chromium oxide layer without adversely altering the morphology of the surface of the filigree steel articles.

Gemäß einem bevorzugten Merkmal der Erfindung wird die Sauerstoffkonzentration mittels eines Sensors stetig oder intervallweise gemessen. Eine mit dem Sensor verbundene Steuerungseinheit überprüft den Ist-Wert hierbei stetig oder intervallweise mit einem frei wählbaren Soll-Wert und gibt den Ofen im Falle einer Identität zwischen Ist-und Soll-Wert für einen zweiten Verfahrensschritt frei. Das erfindungsgemäße Verfahren ist hierdurch in vorteilhafterweise stark vereinfacht und minimiert auf diese Weise mögliche benutzerseitige Fehlerquellen.According to a preferred feature of the invention, the oxygen concentration is measured continuously or at intervals by means of a sensor. A control unit connected to the sensor checks the actual value here continuously or at intervals with a freely selectable desired value and releases the oven in the case of an identity between actual and desired value for a second method step. The inventive method is thereby greatly simplified in an advantageous manner and minimizes in this way possible user-side sources of error.

Erfindungsgemäß ist ein zweiter Verfahrensschritt vorgesehen, in welchem der Tiefzieh- oder Stanzbiegeartikel auf die Zieltemperatur, die zweite Temperatur, für die Randschichthärtung erwärmt wird. Die zweite Temperatur ist so gewählt, dass diese deutlich unterhalb der Rekristallisationstemperatur von stark kaltverformten Eisenlegierungen (680 °C) liegt. Eine mögliche Änderung der Morphologie der Oberfläche ist hierbei wirkungsvoll unterbunden, wodurch die Ausbildung einer homogenen Randschicht gefördert wird. Die zweite Temperatur liegt bei 450 °C bis 550 °C und besonders bevorzugt bei 500 °C. Die Aufheizphase dient hierbei insbesondere der behutsamen und vollständigen Depassivierung der Chromoxidschicht.According to the invention, a second method step is provided, in which the thermoforming or stamped bent article is heated to the target temperature, the second temperature, for the surface hardening. The second temperature is chosen so that it is well below the recrystallization temperature of strongly cold-worked iron alloys (680 ° C). A possible change in the morphology of the surface is thereby effectively prevented, whereby the formation of a homogeneous surface layer is promoted. The second temperature is 450 ° C to 550 ° C, and more preferably 500 ° C. The heating phase serves in particular the careful and complete depassivation of the chromium oxide layer.

Es ist vorteilhaft, die Aufheizrate wenigstens in bestimmten Temperaturbereichen möglichst niedrig zu wählen, um eine gleichmäßige Depassivierung zur gewährleisten. Der Anmelder hat in diesem Zusammenhang herausgefunden, dass die Qualität der resultierenden Randschicht von dünnwandigen Tiefziehteilen in besonderer Weise unter einer hohen Aufheizrate leidet. Bevorzugterweise beträgt die Aufheizrate in einem bestimmten Temperaturbereich zwischen 0,5 und 1 °C/min, weiter bevorzugt zwischen 0,5 und 0,7 °C/min und besonders bevorzugt 0,5 °C/min. Der Temperaturbereich in dem diese niedrige Aufheizrate gewählt wird, beträgt bevorzugterweise 420 °C bis 550 °C, weiter bevorzugt 450 °C bis 500 °C und besonders bevorzugt 480 °C bis 500 °C.It is advantageous to select the heating rate as low as possible, at least in certain temperature ranges, in order to ensure uniform depassivation. The Applicant has found in this context that the quality of the resulting edge layer of thin-walled deep-drawn parts suffers in a special way under a high heating rate. Preferably, the heating rate in a certain temperature range between 0.5 and 1 ° C / min, more preferably between 0.5 and 0.7 ° C / min and more preferably 0.5 ° C / min. The temperature range in which this low heating rate is selected is preferably 420 ° C to 550 ° C, more preferably 450 ° C to 500 ° C, and most preferably 480 ° C to 500 ° C.

Gemäß einem Merkmal der Erfindung wird das erste Gasgemisch im zweiten Verfahrensschritt durch ein zweites Gasgemisch ersetzt. Es hat sich hierbei herausgestellt, dass eine milde Depassivierung der dünnwandigen Tiefziehteile während der Aufheizphase auf die zweite Temperatur durch ein Gasgemisch bestehend aus einem wasserstoffhaltigen Gas, einem stickstoffhaltigen Gas sowie einem kohlenstoffhaltigen Gas erfolgt. Insbesondere in Verbindung mit der niedrigen Aufheizrate kann bevorzugterweise eine besonders langsame und daher milde und gut steuerbare Depassivierung der Chromoxidschicht erreicht werden.According to a feature of the invention, the first gas mixture is replaced by a second gas mixture in the second method step. It has been found that mild depassivation of the thin-walled deep-drawn parts during the heating phase to the second temperature by a gas mixture consisting of a hydrogen-containing gas, a nitrogen-containing gas and a carbon-containing gas. Particularly in connection with the low heating rate, a particularly slow and therefore mild and readily controllable depassivation of the chromium oxide layer can be achieved.

Gemäß einem bevorzugten Merkmal der Erfindung wird der Artikel mit Zusätzen behandelt, die die Passivschicht selektiv oder in Gänze auflösen. Insbesondere sind damit Salzverbindungen und/oder organische Stoffe und Säurebildner gemeint, die in fester oder flüssiger Form auf der Ware oder im Ofen appliziert werden. Die Applikation erfolgt hierbei bevorzugt entweder vor Verbringung des Artikels in den Ofen oder während des zweiten Verfahrensschritts. Hierfür werden Feststoff und/oder Flüssigkeiten verwendet, die in Verbindung mit den Reaktionsgasen saure Reaktionsprodukte bilden, die bei Einleitung in Wasser einen pH-Wert < 7 ergeben würden. Als besonders vorteilhaft hat sich dabei die Applizierung der Stoffe direkt auf oder in der Artikeloberfläche erwiesen. Hierdurch entstehen bereits bei niedrigen Temperaturen lokale Depassivierungsvorgänge, die eine gleichmäßige Depassivierung früher einleiten und fördern.According to a preferred feature of the invention, the article is treated with additives which selectively or completely dissolve the passive layer. In particular, it means salt compounds and / or organic substances and acid generators, which are applied in solid or liquid form to the product or in the oven. The application is preferably carried out either before the article is placed in the oven or during the second process step. For this purpose, solid and / or liquids are used, which in Compound with the reaction gases form acidic reaction products that would give a pH <7 when introduced into water. The application of the substances directly on or in the article surface has proved to be particularly advantageous. As a result, local depassivation processes, which initiate and promote uniform depassivation earlier, occur even at low temperatures.

Als kohlenstoffhaltige Komponente können dem zweiten Gasgemisch Kohlenstoffoxide, gesättigte und ungesättigte Kohlenwasserstoffe beigefügt werden. Besonders bevorzugt ist hierbei der Einsatz von Kohlenstoffoxiden, wie insbesondere Kohlenstoffmonoxid.As the carbonaceous component, carbon oxides, saturated and unsaturated hydrocarbons can be added to the second gas mixture. Particularly preferred here is the use of carbon oxides, in particular carbon monoxide.

Als stickstoffhaltige Komponente können dem zweiten Gasgemisch elementarer Stickstoff, Ammoniak und Stickoxide beigefügt werden. Besonders bevorzugt ist hierbei der Einsatz von Ammoniak.As the nitrogen-containing component elementary nitrogen, ammonia and nitrogen oxides can be added to the second gas mixture. Particularly preferred here is the use of ammonia.

Es hat sich darüber hinaus herausgestellt, dass der Einsatz von elementarem Wasserstoff als Bestandteil des zweiten Gasgemisches zur Ausbildung besonders homogener Randschichten führt.It has also been found that the use of elemental hydrogen as part of the second gas mixture leads to the formation of particularly homogeneous surface layers.

Gemäß einem bevorzugten Merkmal der Erfindung wird die Temperatur mittels eines Sensors stetig oder intervallweise gemessen. Die mit dem Sensor verbundene Steuerungseinheit überprüft den Ist-Wert hierbei stetig oder intervallweise mit einem frei wählbaren Soll-Wert für die zweite Temperatur und gibt den Ofen im Falle einer Identität zwischen Ist- und Soll-Wert für einen dritten Verfahrensschritt frei. Das erfindungsgemäße Verfahren ist hierdurch in vorteilhafterweise stark vereinfacht und minimiert auf diese Weise mögliche benutzerseitige Fehlerquellen.According to a preferred feature of the invention, the temperature is measured continuously or at intervals by means of a sensor. The control unit connected to the sensor checks the actual value here continuously or at intervals with a freely selectable setpoint value for the second temperature and releases the oven in the case of an identity between the actual and setpoint values for a third method step. The inventive method is thereby greatly simplified in an advantageous manner and minimizes in this way possible user-side sources of error.

Erfindungsgemäß ist ein dritter Verfahrensschritt vorgesehen, bei dem der Artikel konstant auf der zweiten Temperatur gehalten wird. Der dritte Verfahrensschritt dient in diesem Zusammenhang der Nitrocarburierung des dünnwandigen Artikels und führt durch Aufkohlung und Aufstickung des Randbereiches des Stahlartikels zur Ausbildung einer gehärteten Randschicht. Es hat sich gezeigt, dass die zweite Temperatur in vorteilhafterweise einen behutsamen Aufbau der gehärteten Randschicht ermöglicht. Die Diffusion des Kohlenstoffes und des Stickstoffes in den Randbereich des Tiefziehteils erfolgt bei diesen Temperaturen langsam, ist infolgedessen gut steuerbar und bewirkt den Aufbau einer homogenen Randschicht. Durch die erfindungsgemäße Verfahrensführung wird insbesondere der Aufbau einer Randschicht gefördert, die aus einer näher am Kern gelegenen kohlenstoffreichen Phase und einer äußeren stickstoffreichen Phase besteht. Eine zu hohe Temperatur ist in jedem Fall zu vermeiden, da es infolge der hohen Diffusionsgeschwindigkeit und der hohen kinetischen Energie der beteiligten Moleküle zur Ausbildung unregelmäßiger Schichten und zur Bildung von Carbid- und/oder Nitrid-Partikeln kommt.According to the invention, a third method step is provided in which the article is kept constant at the second temperature. The third process step is in this context the nitrocarburizing of the thin-walled article and leads by carburizing and nitriding of the edge region of the steel article to form a hardened surface layer. It has been found that the second temperature advantageously allows a careful construction of the hardened surface layer. The diffusion of the carbon and nitrogen in the edge region of the deep-drawn part takes place slowly at these temperatures, is therefore well controlled and causes the Structure of a homogeneous surface layer. The method according to the invention promotes, in particular, the formation of a boundary layer which consists of a carbon-rich phase closer to the core and an outer nitrogen-rich phase. Too high a temperature is to be avoided in any case, as it comes to the formation of irregular layers and the formation of carbide and / or nitride particles due to the high diffusion rate and the high kinetic energy of the molecules involved.

In erfindungsgemäße Weise wird das zweite Gasgemisch zur Nitrocarburierung des Tiefziehartikels verwendet. Das zweite Gasgemisch bewirkt, insbesondere in Verbindung mit der milden Temperatur, einen besonders schonenden und kontrollierten Aufbau der erfindungsgemäßen, aus einer kohlenstoffreichen und einer stickstoffreichen Phase gebildeten, Randschicht.In accordance with the invention, the second gas mixture is used for nitrocarburizing the thermoforming article. The second gas mixture causes, especially in conjunction with the mild temperature, a particularly gentle and controlled construction of the boundary layer according to the invention, formed from a carbon-rich and a nitrogen-rich phase.

Es hat sich herausgestellt, dass insbesondere der Einsatz von Kohlenstoffmonoxid bei diesem Verfahren zu einer besonders homogenen kohlenstoffreichen Phase führt.It has been found that in particular the use of carbon monoxide in this process leads to a particularly homogeneous carbon-rich phase.

Desweiteren hat sich herausgestellt, dass die Verwendung von Ammoniak die Ausbildung einer besonders homogenen stickstoffreichen Phase fördert.Furthermore, it has been found that the use of ammonia promotes the formation of a particularly homogeneous nitrogen-rich phase.

Gemäß einem bevorzugten Merkmal der Erfindung werden die einzelnen Konzentrationen der Gaskomponenten mittels jeweiliger Sensoren stetig oder intervallweise gemessen. Die mit den Sensoren verbundene Steuerungseinheit überprüft die jeweiligen Ist-Werte hierbei stetig oder intervallweise mit frei wählbaren Soll-Werten für die jeweilige Konzentration der Gaskomponente und gleicht Änderungen innerhalb einer Fehlertoleranz stetig oder intervallweise aus. Auf diese Weise ist die Verfahrensführung in vorteilhafter Weise vereinfacht und erlaubt die Bereitstellung konstanter Verfahrensbedingungen, was für den Aufbau einer homogenen kohlenstoffreichen Randschicht von entscheidender Bedeutung ist.According to a preferred feature of the invention, the individual concentrations of the gas components are measured continuously or at intervals by means of respective sensors. The control unit connected to the sensors checks the respective actual values continuously or at intervals with freely selectable desired values for the respective concentration of the gas component and compensates for changes within a fault tolerance continuously or at intervals. In this way, the process control is advantageously simplified and allows the provision of constant process conditions, which is for the construction of a homogeneous carbon-rich surface layer of crucial importance.

Die Schichtdicke der kohlenstoffreichen Randschicht ist hierbei über die Begasungsdauer einstellbar. In vorteilhafter Weise wird zur Generierung einer 5 bis 35 µm dicken Randschicht ein Zeitraum von 2 bis 20 Stunden benötigt.The layer thickness of the carbon-rich surface layer can be adjusted over the gassing time. Advantageously, a period of 2 to 20 hours is required to generate a 5 to 35 .mu.m thick edge layer.

Gemäß einem bevorzugten Merkmal der Erfindung gibt die Steuereinheit, welche zur Zeiterfassung über eine entsprechende Vorrichtung verfügt, nach Ablauf einer frei wählbaren Nitrocarburierungszeit den Ofen für den vierten Verfahrensschritt frei. Das erfindungsgemäße Verfahren ist hierdurch in vorteilhafterweise stark vereinfacht und minimiert auf diese Weise mögliche benutzerseitige Fehlerquellen.According to a preferred feature of the invention, the control unit which provides for Time recording on a corresponding device has, after an arbitrary Nitrocarburierungszeit a free oven for the fourth step. The inventive method is thereby greatly simplified in an advantageous manner and minimizes in this way possible user-side sources of error.

Erfindungsgemäß ist ein vierter Verfahrensschritt vorgesehen, bei dem das Tiefziehteil auf eine dritte Temperatur abgekühlt wird. Es ist hierbei vorgesehen, das Tiefziehteil auf eine Temperatur von 50 °C bis 80 °C und besonders bevorzugt 60 °C abzukühlen.According to the invention, a fourth method step is provided in which the deep-drawn part is cooled to a third temperature. It is provided here, the deep-drawn part to a temperature of 50 ° C to 80 ° C and more preferably cool to 60 ° C.

Es hat sich hierbei herausgestellt, dass die Wahl der Atmosphäre in der abgekühlt wird für die Ausbildung einer homogenen Randschicht von entscheidender Bedeutung ist. Es ist daher gemäß der Erfindung vorgesehen, das zweite Gasgemisch durch ein drittes Gasgemisch zu ersetzen. Insbesondere die Wahl eines leicht reduzierend wirkenden Gasgemisches wird als vorteilhaft angesehen. Gemäß einer Ausgestaltung der Erfindung besteht das dritte Gasgemisch aus H2 und N2. Um ein schwaches Reduktionspotential zu gewährleisten, besteht die Zusammensetzung des dritten Gasgemisches vorteilhafterweise aus 5 % bis 25 % H2 und 75 % bis 95 % N2, weiter bevorzugt 5 % bis 10 % H2 und 90 % bis 95 % N2 und besonders bevorzugt 5 % H2 und 95 % N2. Es hat sich gezeigt, dass das erfindungsgemäße Abkühlen des dünnwandigen Tiefziehteils ein Entweichen sowohl des Kohlenstoffs als auch des Stickstoffs aus der gehärteten Randschicht wirkungsvoll unterbindet und den Einschluss beider Komponenten in gelöster Form fördert.It has been found that the choice of atmosphere in the cooled is crucial for the formation of a homogeneous surface layer. It is therefore provided according to the invention to replace the second gas mixture by a third gas mixture. In particular, the choice of a slightly reducing gas mixture is considered advantageous. According to one embodiment of the invention, the third gas mixture of H 2 and N 2 . To ensure a low reduction potential, the composition of the third gas mixture advantageously consists of 5% to 25% H 2 and 75% to 95% N 2 , more preferably 5% to 10% H 2 and 90% to 95% N 2 and especially preferably 5% H 2 and 95% N 2 . It has been found that the inventive cooling of the thin-walled deep-drawn part effectively prevents escape of both the carbon and the nitrogen from the hardened surface layer and promotes the inclusion of both components in dissolved form.

Des Weiteren betrifft die Erfindung einen nitrocarburierten Tiefziehartikel aus austenitischem nichtrostendem Edelstahl mit einer für Tiefziehartikeln üblichen, wenigstens bereichsweise geringen Wandstärke.Furthermore, the invention relates to a nitrocarburized thermoforming article made of austenitic stainless steel with a standard for thermoforming articles, at least partially low wall thickness.

Mittels des erfindungsgemäßen Verfahrens ist es nun erstmals möglich, einen Tiefziehartikel mit dünner Wandstärke industriell reproduzierbar und in exzellenter Qualität zu härten.By means of the method according to the invention, it is now possible for the first time to harden a thermoformed article with thin wall thickness in an industrially reproducible manner and in excellent quality.

Der erfindungsgemäße Tiefziehartikel weist einen weichen bzw. je nach Kaltverformung kaltverfestigteren elastischen Kern und eine harte Randschicht auf.The deep-drawing article according to the invention has a soft or depending on the cold deformation cold-strengthened elastic core and a hard edge layer on.

Gemäß einem erfindungswesentlichen Merkmal ist die Randschicht frei von Defektstellen und/oder Partikeln, umlaufend vollständig geschlossen und weist eine im Wesentlichen plan ausgebildet Oberfläche auf.According to a feature essential to the invention, the edge layer is free of defects and / or particles, circumferentially completely closed and has a substantially planar surface.

Der erfindungsgemäße dünnwandige Tiefziehartikel weist infolgedessen mechanische Eigenschaften bisher unerreichter Qualität auf.As a result, the thin-walled thermoforming article according to the invention has mechanical properties of unprecedented quality.

So sind die Korrosions- und die Abriebbeständigkeit des Tiefziehartikels in erfindungsgemäßer Weise besser als die des Ausgangsproduktes. Ermöglicht wird dies durch den erfindungsgemäßen Aufbau der Randschicht. Die Randschicht besteht aus einer äußeren stickstoffreichen Phase und einer zwischen Kern und stickstoffreicher Phase angeordneten kohlenstoffreichen Phase. Die kohlenstoffreiche Phase weist hierbei eine Härte von 700 bis 1000 HV0,025 und eine Schichtdicke von 2,5 bis 15 µm auf. Die stickstoffreiche Phase hingegen weist eine Härte von 1000 bis 1400 HV0,025 und eine Schichtdicke von 2,5 bis 20 µm auf.Thus, the corrosion and abrasion resistance of the thermoforming article in the inventive way better than that of the starting material. This is made possible by the structure according to the invention of the surface layer. The surface layer consists of an outer nitrogen-rich phase and a carbon-rich phase located between the core and the nitrogen-rich phase. The carbon-rich phase in this case has a hardness of 700 to 1000 HV0.025 and a layer thickness of 2.5 to 15 microns. The nitrogen-rich phase, however, has a hardness of 1000 to 1400 HV0.025 and a layer thickness of 2.5 to 20 microns.

Auf diese Weise wird in vorteilhafter Weise ein Härtegradient ausgehend vom weichen Kern zur härteren kohlenstoffreichen Phase zur noch härteren stickstoffreichen Phase gebildet. Das Material ist hierdurch in vorteilhafter Weise in seinem Kernbereich flexibel und in seinem Randbereich gehärtet. Dadurch, dass eine zweiphasige Randschicht mit unterschiedlicher Härte ausgebildet ist, weist auch die Randschicht eine erhöhte Flexibilität bei gleichzeitiger enormer Härte auf.In this way, a hardness gradient is advantageously formed from the soft core to the harder carbon-rich phase to the even harder nitrogen-rich phase. The material is thereby advantageously flexible in its core region and cured in its edge region. Characterized in that a two-phase edge layer is formed with different hardness, also the edge layer has an increased flexibility with simultaneous enormous hardness.

Claims (6)

  1. A method for the thin-wall nitrocarburization of a deep-drawn article or a punched-bent article made of austenitic stainless steel,
    in which the article, which comprises a wall thickness in at least some areas of less than 2000 µm, is introduced into a furnace in a first process step and heated up to a first temperature comprised between 100°C and 140°C,
    wherein an oxygen-bearing atmosphere which is present in the furnace will be replaced by a first gas mixture, wherein the first gas mixture consists of H2 and N2,
    and in which the article is heated up to a second temperature comprised between 450°C and 550°C in a second process step,
    wherein the first gas mixture will be replaced by a second gas mixture, wherein the second gas mixture consists of H2, a nitrogen-bearing gas of the group comprising elementary nitrogen, ammonia and nitrogen oxides and of a carbon-bearing gas of the group comprising carbon oxides, saturated hydrocarbons and unsaturated hydrocarbons,
    and in which the article is maintained at the second temperature in a third process step,
    wherein the article will be treated with the second gas mixture,
    and in which the article is cooled down to a third temperature comprised between 50°C and 80°C in a fourth process step,
    wherein the second gas mixture will be replaced by a third gas mixture, wherein the third gas mixture consists of H2 and N2.
  2. A method according to claim 1, characterized in that the residual oxygen content will be measured by means of a sensor during the first process step and if a freely selectable residual oxygen value is achieved, the second process step will be automatically initiated.
  3. A method according to one of the preceding claims, characterized in that if the second temperature is reached, the third process step will be automatically initiated.
  4. A method according to one of the preceding claims, characterized in that the article will be treated with at least one depassivating salt compound.
  5. A method according to one of the preceding claims, characterized in that after the expiry of a freely selectable treatment period, the fourth process step will be automatically initiated.
  6. A nitrocarburized deep drawn article made of austenitic stainless steel and nitrocarburized by a method according to one of the claims 1 through 5,
    comprising a small wall thickness of less than 2000 µm in at least some areas, which wall thickness is usual for deep drawn articles,
    a core
    as well as an edge layer,
    wherein the edge layer is harder than the core and
    wherein the edge layer is free of defect sites and/or particles, is circumferentially closed and comprises an essentially flat surface,
    and wherein the edge layer is formed by an outer nitrogen rich phase and a carbon rich phase arranged between the core and the nitrogen rich phase,
    and wherein the abrasion resistance of the edge layer is higher than the one of the starting material,
    wherein the carbon rich phase comprises a hardness comprised between 700 and 1000 HV0,025 and a layer thickness comprised between 2.5 and 15 µm,
    and wherein the nitrogen rich phase comprises a hardness comprised between 1000 and 1400 HV0,025 and a layer thickness comprised between 2.5 and 20 µm.
EP13196075.9A 2013-12-06 2013-12-06 Process for the nitrocarburization of a deep drawn article or a bent pressed article made of austenitic stainless steel Active EP2881493B1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
PL13196075T PL2881493T3 (en) 2013-12-06 2013-12-06 Process for the nitrocarburization of a deep drawn article or a bent pressed article made of austenitic stainless steel
EP13196075.9A EP2881493B1 (en) 2013-12-06 2013-12-06 Process for the nitrocarburization of a deep drawn article or a bent pressed article made of austenitic stainless steel
US14/557,592 US9738964B2 (en) 2013-12-06 2014-12-02 Method for the nitro carburization of a deep-drawn part or a stamped-bent part made of austenitic stainless steel
CN201410734836.4A CN104694873B (en) 2013-12-06 2014-12-04 Method for carrying out nitro carburizing to the deep-draw part made of austenitic stainless steel or punching press bending member

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP13196075.9A EP2881493B1 (en) 2013-12-06 2013-12-06 Process for the nitrocarburization of a deep drawn article or a bent pressed article made of austenitic stainless steel

Publications (2)

Publication Number Publication Date
EP2881493A1 EP2881493A1 (en) 2015-06-10
EP2881493B1 true EP2881493B1 (en) 2016-08-24

Family

ID=49724509

Family Applications (1)

Application Number Title Priority Date Filing Date
EP13196075.9A Active EP2881493B1 (en) 2013-12-06 2013-12-06 Process for the nitrocarburization of a deep drawn article or a bent pressed article made of austenitic stainless steel

Country Status (4)

Country Link
US (1) US9738964B2 (en)
EP (1) EP2881493B1 (en)
CN (1) CN104694873B (en)
PL (1) PL2881493T3 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11926880B2 (en) * 2021-04-21 2024-03-12 General Electric Company Fabrication method for a component having magnetic and non-magnetic dual phases

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2633076B2 (en) * 1990-10-04 1997-07-23 大同ほくさん株式会社 Hard austenitic stainless steel screw and its manufacturing method
DE3933053C1 (en) 1989-10-04 1990-05-03 Degussa Ag, 6000 Frankfurt, De
TW237484B (en) * 1992-09-16 1995-01-01 Daido Oxygen
FR2713205B1 (en) 1993-11-29 1997-01-03 Gene Stull Spray distributor cap.
EP0678589B1 (en) 1994-04-18 1999-07-14 Daido Hoxan Inc. Method of carburizing austenitic metal
US6093303A (en) 1998-08-12 2000-07-25 Swagelok Company Low temperature case hardening processes
US6547888B1 (en) * 2000-01-28 2003-04-15 Swagelok Company Modified low temperature case hardening processes
JP2001330038A (en) 2000-03-17 2001-11-30 Nsk Ltd Rolling supporting device
JP3961390B2 (en) * 2002-10-04 2007-08-22 エア・ウォーター株式会社 Surface carbonitrided stainless steel parts with excellent wear resistance and manufacturing method thereof
JP4295350B1 (en) * 2008-09-17 2009-07-15 エア・ウォーター株式会社 Method of using heat treatment furnace, heat treatment method and heat treatment furnace
DE102009056875B4 (en) * 2009-12-03 2013-07-11 Bosch Mahle Turbo Systems Gmbh & Co. Kg Bearing housing, charging device and method for surface treatment of a bearing housing
US8696830B2 (en) 2010-07-21 2014-04-15 Kenneth H. Moyer Stainless steel carburization process
EP2627795A1 (en) * 2010-10-11 2013-08-21 Ipsen International GmbH Method and arrangement for carburizing and carbonitriding metallic materials
FR2980804B1 (en) * 2011-09-30 2014-06-27 Areva Np PROCESS FOR MAKING A LOW CARBON AUSTENITIC STAINLESS STEEL MIXTURE OF A WEAR AND CORROSION RESISTANT SHEATH FOR CORRESPONDING NUCLEAR REACTOR, SHEATH AND CLUSTER

Also Published As

Publication number Publication date
CN104694873B (en) 2018-03-16
CN104694873A (en) 2015-06-10
EP2881493A1 (en) 2015-06-10
US20150159262A1 (en) 2015-06-11
US9738964B2 (en) 2017-08-22
PL2881493T3 (en) 2017-02-28

Similar Documents

Publication Publication Date Title
DE69933687T2 (en) SELECTIVE HARDENING AT LOW TEMPERATURE
EP1865088B1 (en) Method for tempering stainless steel and fused salt for performing the method
DE4033706C2 (en)
DE2658174A1 (en) PROCESS FOR NITRIFIED MARTENSITIC STEELS
DE102014103742B4 (en) METHOD FOR PRODUCING A FERRITIC STAINLESS STEEL PRODUCT
EP2872787A1 (en) Rolling bearing element, in particular rolling bearing ring
EP2881492B1 (en) Method for carburising metal deep drawn article or a bent pressed article made of austenitic stainless steel
EP2024527A2 (en) Method for hardening running surfaces of roller bearing components
CH666288A5 (en) STEEL DIE, METHOD FOR THE PRODUCTION AND USE THEREOF.
EP2881493B1 (en) Process for the nitrocarburization of a deep drawn article or a bent pressed article made of austenitic stainless steel
DE4400391A1 (en) Process to avoid edge oxidation when carburizing steels
DE1621265C3 (en) Process for surface hardening of titanium or titanium alloys
DE2605177C2 (en) Method for manufacturing a bearing part
DE102016208485A1 (en) Process for the production of sliding bearing composite materials, sliding bearing composite material and sliding element made of such sliding bearing composite materials
EP2055801B1 (en) Method for hardening stainless steel surfaces on workpieces and fused salt for performing the method
DE102015204656A1 (en) Layer formation for rolling bearing components
DE3537658C2 (en)
DE3804824C2 (en)
DE3219071A1 (en) Process for plating titanium with a hard layer
DE2149835A1 (en) Process to improve the fatigue strength and wear resistance, the sliding properties and the corrosion resistance of workpiece surfaces made of iron and steel
WO2010009718A2 (en) Component made of an unalloyed or low-alloy steel, method for protecting said components against coke deposition or metal dusting
DE3827141C1 (en) Process for alitising objects of austenitic steel or nickel-based alloys
DE1771388C3 (en) Process for the manufacture of metal parts exposed to frictional stress
DE60217344T2 (en) METHOD FOR SCRUBBING STEEL BY MEANS OF COMPRESSED AIR
DE1262731B (en) Process for the production of case-hardened workpieces

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

17P Request for examination filed

Effective date: 20150311

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

17Q First examination report despatched

Effective date: 20151210

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

INTG Intention to grant announced

Effective date: 20160517

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: AT

Ref legal event code: REF

Ref document number: 823176

Country of ref document: AT

Kind code of ref document: T

Effective date: 20160915

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: LANGUAGE OF EP DOCUMENT: GERMAN

REG Reference to a national code

Ref country code: CH

Ref legal event code: NV

Representative=s name: E. BLUM AND CO. AG PATENT- UND MARKENANWAELTE , CH

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 502013004148

Country of ref document: DE

REG Reference to a national code

Ref country code: NL

Ref legal event code: FP

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 4

REG Reference to a national code

Ref country code: LT

Ref legal event code: MG4D

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: RS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: HR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: NO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20161124

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 FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20161125

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20161226

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 502013004148

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: SM

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20161231

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20161124

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

Effective date: 20170526

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

REG Reference to a national code

Ref country code: IE

Ref legal event code: MM4A

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20161206

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20161206

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 5

REG Reference to a national code

Ref country code: DE

Ref legal event code: R082

Ref document number: 502013004148

Country of ref document: DE

Representative=s name: BRINKMANN & PARTNER PATENTANWAELTE PARTNERSCHA, DE

Ref country code: DE

Ref legal event code: R082

Ref document number: 502013004148

Country of ref document: DE

Representative=s name: RAUSCH WANISCHECK-BERGMANN BRINKMANN PARTNERSC, DE

Ref country code: BE

Ref legal event code: MM

Effective date: 20161231

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO

Effective date: 20131206

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: MK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20160824

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: PL

Payment date: 20221124

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 20221213

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20230227

Year of fee payment: 10

P01 Opt-out of the competence of the unified patent court (upc) registered

Effective date: 20230523

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20231220

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20231220

Year of fee payment: 11

Ref country code: IT

Payment date: 20231228

Year of fee payment: 11

Ref country code: FR

Payment date: 20231221

Year of fee payment: 11

Ref country code: CZ

Payment date: 20231127

Year of fee payment: 11

Ref country code: AT

Payment date: 20231221

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: PL

Payment date: 20231123

Year of fee payment: 11