EP2773789B1 - Procede de carbonitruration a etape de nitruration finale pendant une descente de temperature - Google Patents
Procede de carbonitruration a etape de nitruration finale pendant une descente de temperature Download PDFInfo
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- EP2773789B1 EP2773789B1 EP12772768.3A EP12772768A EP2773789B1 EP 2773789 B1 EP2773789 B1 EP 2773789B1 EP 12772768 A EP12772768 A EP 12772768A EP 2773789 B1 EP2773789 B1 EP 2773789B1
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- temperature
- phase
- nitriding
- initial
- nitridation
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- 238000000034 method Methods 0.000 title claims description 18
- 238000005256 carbonitriding Methods 0.000 title claims description 11
- 230000007423 decrease Effects 0.000 title description 2
- 229910000831 Steel Inorganic materials 0.000 claims description 8
- 239000010959 steel Substances 0.000 claims description 8
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 238000002791 soaking Methods 0.000 claims 2
- 238000005121 nitriding Methods 0.000 description 38
- 238000010791 quenching Methods 0.000 description 8
- 230000000171 quenching effect Effects 0.000 description 8
- 238000005255 carburizing Methods 0.000 description 7
- 238000009792 diffusion process Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/28—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases more than one element being applied in one step
- C23C8/30—Carbo-nitriding
- C23C8/32—Carbo-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
- C23C8/02—Pretreatment of the material to be coated
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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
- C23C8/20—Carburising
- C23C8/22—Carburising 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
- C23C8/06—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
-
- 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 present invention relates to a process for carbonitriding steel parts, including, but not limited to, parts used in the manufacture of motor vehicles.
- the invention also applies to parts used in the manufacture of agricultural machinery, machine tool, or parts in the aeronautical field.
- the object of the invention is to improve the process of the aforementioned document, that is to say to improve the quality of the parts obtained, preferably with a reduction of the treatment time.
- the final nitriding step comprises a temperature step.
- the last nitriding step is thus carried out under optimal conditions.
- the temperature rise is carried out with a reduced temperature gradient compared to the simple temperature rise phase.
- the nitrogen enrichment which is carried out under favorable conditions for good nitriding is increased so that it is possible to shorten or eliminate one of the subsequent nitriding steps and thus reduce the total treatment time.
- the method according to the invention comprises a first step of temperature rise comprising a first phase M of simple temperature rise, illustrated by a line in continuous line, from the ambient temperature to a point at a temperature of 700 ° C. , denoted Ni1 in the figure.
- the phase simple rise in temperature can be carried out up to a temperature of between 700 ° C. and 750 ° C., and has a duration of between 10 min and 90 min, that is to say that the simple rise in temperature is carried out with a temperature gradient of between 8 ° C / min and 75 ° C / min.
- the process then comprises an initial nitriding phase Ni with continuation of the temperature rise step up to a temperature of 940 ° C. in the example illustrated.
- the temperature of 940 ° C corresponds to a compromise between a temperature of 860 ° C which allows a treatment of better quality and a temperature of 1000 ° C which allows for faster processing.
- the rise in temperature continues on a regular basis but with a temperature gradient of between 3.5 ° C./min and 16 ° C./min less than the temperature gradient during the simple temperature rise.
- the duration of the initial nitriding phase is between 15 minutes and 45 minutes, depending on the amount of nitrogen that it is desired to set in this initial step and the composition of the steel to be treated.
- the initial nitriding phase comprises injection phases of a nitriding gas such as alternating ammonia with diffusion phases.
- the rise in temperature continues with the same temperature gradient as during the simple rise in temperature to a point at a temperature between 750 ° C and 850 ° C, here 800 ° C, denoted Ni2 in the figure.
- the temperature is then maintained according to a plateau until a moment noted Ni3 on the figure 2 from which a high temperature rise is performed to reach the carburizing temperature.
- the temperature of the bearing is chosen in a manner known per se to perform the initial nitriding phase under optimal conditions given the composition of the parts to be treated. Note in this connection that because of the bearing, the final temperature rise can be performed very rapidly, for example 80 ° C / min at 100 ° C / min without subjecting the parts to unacceptable constraints.
- the rise in temperature continues from point Ni1 with a lower temperature gradient than in the first embodiment, preferably in a range of 2 ° C / min to 8 ° C / min, up to Ni4 moment, corresponding here to a temperature of 850 ° C, from which a high temperature rise is performed to reach the carburizing temperature, according to a gradient similar to that of the second embodiment.
- the process then comprises n alternating cementation phases with nitriding phases.
- the carburizing and nitriding steps comprise alternating treatment gas injection phases with diffusion phases not shown in the figures.
- the diagram has been interrupted between the nitriding step N1 and the last cementation step Cn.
- the process comprises a final nitriding step Nn accompanied by a descent of temperature immediately before T quenching.
- the temperature is lowered continuously to a temperature within the optimum temperature range for all nitriding. remaining high enough to allow efficient quenching.
- the final temperature before quenching is 840 ° C.
- this limited descent of temperature decreases the stress on the parts during quenching.
- the final nitriding step has a duration of preferably between 15 min and 60 min, which corresponds to a temperature gradient of between 10 ° C / min and 1 ° C / min.
- the final nitriding step preferably comprises alternating nitriding gas injection phases with diffusion phases.
- the descent of temperature is first of all carried out in a strong way, with a gradient as strong as possible without generating undue stresses in the steel, up to the optimum nitriding temperature for the steel being treated, noted Nn1 in the figure, here 840 ° C, then the temperature is maintained at a plateau until the beginning of quenching.
- the method according to the invention can be implemented by combining any one of the embodiments of the initial nitriding phase with any of the embodiments of the final nitriding phase.
- the initial rise in temperature can be carried out according to a constant gradient as illustrated by a dashed line in the figure.
- the initial rise in temperature can be carried out according to a constant gradient as illustrated by a dashed line in the figure.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Heat Treatment Of Articles (AREA)
Description
- La présente invention revendique la priorité de la demande française
1159878 déposée le 31 octobre 2011 - La présente invention concerne un procédé de carbonitruration de pièces en acier, notamment bien que non exclusivement, des pièces entrant dans la fabrication de véhicules automobiles. En particulier l'invention s'applique également à des pièces entrant dans la fabrication de machines agricoles, de machine-outil, ou à des pièces dans le domaine aéronautique.
- On connaît du document
EP 1885904 , un procédé de carbonitruration de pièces en acier comportant des étapes alternées de cémentation et de nitruration à température constante, précédées d'une étape de montée en température et d'une étape d'égalisation en température, et suivies d'une étape de trempe. En variante il est proposé d'injecter un gaz de nitruration pendant l'étape de montée en température et/ou pendant l'étape d'égalisation en température, à partir d'une température de 800°C. - Le but de l'invention est d'améliorer le procédé du document précité, c'est-à-dire d'améliorer la qualité des pièces obtenues, de préférence avec une réduction du temps de traitement.
- En vue de la réalisation de ce but, on propose selon l'invention un procédé de carbonitruration de pièces en acier, notamment des pièces entrant dans la fabrication de véhicules automobiles, conforme à la revendication 1.
- En effet, selon une constatation qui fait déjà partie de l'invention, il a été observé qu'il était possible de démarrer la trempe à partir d'une température plus basse que la température de cémentation. Une descente de température pendant la dernière étape de nitruration permet donc d'effectuer celle-ci dans des conditions plus favorables à une bonne nitruration.
- Selon une version avantageuse de l'invention, l'étape de nitruration finale comporte un palier de température. On effectue ainsi la dernière étape de nitruration dans des conditions optimales.
- De préférence, pendant la phase de nitruration initiale la montée en température est effectuée avec un gradient de température réduit par rapport à la phase de montée en température simple. Ainsi, sans augmenter la durée du traitement on augmente l'enrichissement en azote qui est effectué dans des conditions favorables à une bonne nitruration de sorte qu'il est possible de raccourcir ou de supprimer l'une des étapes de nitruration ultérieure et de réduire ainsi le temps de traitement total.
- D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture de la description qui suit de différents modes de mise en oeuvre particuliers non limitatifs du procédé de carbonitruration basse pression selon l'invention, en référence aux 3 figures annexées qui sont des diagrammes schématiques illustrant les différentes étapes du procédé selon l'invention selon différents variantes de réalisation.
- En référence à la
figure 1 , le procédé selon l'invention comporte une première étape de montée en température comprenant une première phase M de montée en température simple, illustrée par une droite en trait continu, depuis la température ambiante jusqu'à un point à une température de 700°C, noté Ni1 sur la figure. En fonction de la composition de l'acier à traiter, la phase de montée en température simple peut être effectuée jusqu'à une température comprise entre 700°C et 750°C, et a une durée comprise entre 10 min et 90 min c'est-à-dire que la montée en température simple est effectuée avec un gradient de température compris entre 8°C/min et 75°C/min. - Le procédé comporte ensuite une phase de nitruration initiale Ni avec poursuite de l'étape de montée en température jusqu'à une température de 940°C dans l'exemple illustré. En pratique la température de 940°C correspond à un compromis entre une température de 860°C qui permet de réaliser un traitement de meilleure qualité et une température de 1000°C qui permet de réaliser un traitement plus rapide.
- Dans l'exemple de réalisation de la
figure 1 , correspondant à un premier mode de réalisation de la phase de nitruration initiale, la montée en température se poursuit de façon régulière mais avec un gradient de température compris entre 3,5°C/min et 16°C/min inférieur au gradient de température pendant la montée en température simple. La durée de la phase de nitruration initiale est comprise entre 15 min et 45 min, en fonction de la quantité d'azote que l'on souhaite fixer dans cette étape initiale et de la composition de l'acier à traiter. - De façon connue en soi la phase de nitruration initiale comporte des phases d'injection d'un gaz nitrurant tel que de l'ammoniac alternées avec des phases de diffusion.
- Selon un deuxième mode de réalisation de la phase de nitruration initiale, illustré par la
figure 2 , la montée en température se poursuit avec le même gradient de température que pendant la montée en température simple jusqu'à un point à une température comprise entre 750°C et 850°C, ici 800°C, noté Ni2 sur la figure. La température est alors maintenue selon un palier jusqu'à un instant noté Ni3 sur lafigure 2 à partir duquel une montée en température forte est réalisée pour atteindre la température de cémentation. - La température du palier est choisie de façon connue en soi pour réaliser la phase de nitruration initiale dans des conditions optimales compte tenu de la composition des pièces à traiter. On notera à ce propos qu'en raison du palier, la montée en température finale peut s'effectuer de façon très rapide, par exemple 80°C/min à 100°C/min sans soumettre les pièces à des contraintes inacceptables.
- Selon un troisième mode de réalisation de la phase de nitruration initiale, illustré à l'aide de la
figure 3 , la montée en température se poursuit à partir du point Ni1 avec un gradient de température plus faible que dans le premier mode de réalisation, de préférence compris dans une plage de 2°C/min à 8°C/min, jusqu'à un instant noté Ni4, correspondant ici à une température de 850°C, à partir duquel une montée en température forte est réalisée pour atteindre la température de cémentation, selon un gradient analogue à celui du deuxième mode de réalisation. - Quel que soit le mode de réalisation utilisé pour la phase de nitruration initiale, le procédé comporte ensuite n phases de cémentation alternées avec des phases de nitruration. De façon connue en soi les étapes de cémentation et de nitruration comprennent des phases d'injection d'un gaz de traitement alternées avec des phases de diffusion non représentées sur les figures. Sur la figure, le diagramme a été interrompu entre l'étape de nitruration N1 et la dernière étape de cémentation Cn. À l'issue de cette dernière étape de cémentation Cn, le procédé comporte une étape de nitruration finale Nn accompagnée d'une descente de température immédiatement avant la trempe T.
- Selon un premier mode de réalisation de la dernière étape de nitruration Nn, illustré par un trait en tirets courts sur la figure, la descente de température est effectuée de façon continue jusqu'à une température comprise dans la plage de température optimale pour la nitruration tout en restant suffisamment élevée pour permettre une trempe efficace. Dans l'exemple illustré la température finale avant la trempe est de 840°C. En pratique des résultats satisfaisants sont obtenus pour une température finale avant la trempe comprise entre 900°C et 800°C. Il a été constaté que cette descente limitée de température diminue la contrainte sur les pièces lors de la trempe.
- L'étape de nitruration finale à une durée de préférence comprise entre 15 min et 60 min, ce qui correspond à un gradient de température compris entre 10°C/min et 1°C/min. Comme pour la phase de nitruration initiale, l'étape de nitruration finale comporte de préférence des phases d'injection d'un gaz nitrurant alternées avec des phases de diffusion.
- Selon un second mode de réalisation de la dernière étape de nitruration Nn, illustré à la
figure 2 , la descente de température est tout d'abord effectuée de façon forte, avec un gradient aussi fort que possible sans engendrer des contraintes indues dans l'acier, jusqu'à la température de nitruration optimale pour l'acier en cours de traitement, notée Nn1 sur la figure, ici 840°C, puis la température est maintenue à un palier jusqu'au début de la trempe. - En pratique le procédé selon l'invention peut être mis en oeuvre en combinant l'un quelconque des modes de réalisation de la phase de nitruration initiale avec l'un quelconque des modes de réalisation de la phase de nitruration finale.
- On remarquera qu'en raison de l'efficacité accrue des phases de nitruration selon l'invention il est possible de remplacer au moins une étape de nitruration comprise entre deux étapes de cémentation par une étape de diffusion simple. Une telle étape est plus courte qu'une étape de nitruration de sorte que la durée totale du traitement est raccourcie.
- Bien entendu l'invention n'est pas limitée aux modes de mise en oeuvre décrits et on peut y apporter des variantes de réalisation sans sortir du cadre de l'invention telle que définie par les revendications. En particulier la montée en température initiale peut-être effectuée selon un gradient constant comme illustré par un trait en pointillés sur la figure.
- On remarquera qu'en raison de l'efficacité accrue des phases de nitruration selon l'invention il est possible de remplacer au moins une étape de nitruration comprise entre deux étapes de cémentation par une étape de diffusion simple. Une telle étape est plus courte qu'une étape de nitruration de sorte que la durée totale du traitement est raccourcie.
- Bien entendu l'invention n'est pas limitée aux modes de mise en oeuvre décrits et on peut y apporter des variantes de réalisation sans sortir du cadre de l'invention telle que définie par les revendications. En particulier la montée en température initiale peut-être effectuée selon un gradient constant comme illustré par un trait en pointillés sur la figure.
Claims (6)
- Procédé de carbonitruration de pièces en acier, notamment des pièces entrant dans la fabrication de véhicules automobiles, comportant des étapes alternées de cémentation (C1-Cn) et de nitruration (N1-Nn-1) à température constante, précédées d'une étape de montée en température, et suivies d'une étape de trempe (T), caractérisé en ce qu'il comporte une étape de nitruration finale (Nn) accompagnée d'une descente de température immédiatement avant la trempe (T), en ce que la descente de température est effectuée jusqu'à une température comprise entre 900°C et 800°C, en ce que la descente de température est effectuée avec un gradient de température compris entre 10°C/min et 1°C/min et en ce que l'étape de montée en température comprend une phase de montée en température simple (M) suivie d'une phase de nitruration initiale (Ni) avec poursuite de la montée en température et la phase de nitruration initiale (Ni) est réalisée à partir d'une température comprise entre 700°C et 750°C, et jusqu'à une température comprise entre 860°C et 1000°C.
- Procédé de carbonitruration selon la revendication 1, caractérisé en ce que l'étape de nitruration finale comporte un palier de température (Nn2).
- Procédé de carbonitruration selon la revendication 1, caractérisé en ce que pendant la phase de nitruration initiale (N1) la montée en température est effectuée avec un gradient de température réduit par rapport à la phase de montée en température simple (M).
- Procédé de carbonitruration selon la revendication 3, caractérisé en ce que la phase de nitruration initiale (Ni) comporte un palier de température (Ni2-Ni3).
- Procédé de carbonitruration selon la revendication 3, caractérisé en ce que la phase de nitruration initiale (N1) est immédiatement suivie d'une première étape de cémentation (C1).
- Procédé de carbonitruration selon la revendication 1, caractérisé en ce que la phase de nitruration initiale (N1) est effectuée avec un gradient de température compris entre 3,5°C/min et 10°C/min.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1159878A FR2981949B1 (fr) | 2011-10-31 | 2011-10-31 | Procede de carbonitruration a etape de nitruration finale pendant une descente de temperature |
PCT/EP2012/069890 WO2013064337A1 (fr) | 2011-10-31 | 2012-10-08 | Procede de carbonitruration a etape de nitruration finale pendant une descente de temperature |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2773789A1 EP2773789A1 (fr) | 2014-09-10 |
EP2773789B1 true EP2773789B1 (fr) | 2019-02-20 |
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EP12772768.3A Active EP2773789B1 (fr) | 2011-10-31 | 2012-10-08 | Procede de carbonitruration a etape de nitruration finale pendant une descente de temperature |
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Country | Link |
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US (1) | US9938615B2 (fr) |
EP (1) | EP2773789B1 (fr) |
JP (1) | JP6138810B2 (fr) |
KR (1) | KR101945005B1 (fr) |
CN (1) | CN103958720B (fr) |
BR (1) | BR112014010316A2 (fr) |
FR (1) | FR2981949B1 (fr) |
IN (1) | IN2014CN03955A (fr) |
MX (1) | MX357137B (fr) |
WO (1) | WO2013064337A1 (fr) |
Families Citing this family (2)
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FR3028530B1 (fr) * | 2014-11-14 | 2020-10-23 | Peugeot Citroen Automobiles Sa | Procede et installation de carbonitruration de piece(s) en acier sous basse pression et haute temperature |
KR20220074308A (ko) | 2020-11-27 | 2022-06-03 | 시흥시 | 연자육 차 제조방법 |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1454998A1 (fr) * | 2001-12-13 | 2004-09-08 | Koyo Thermo Systems Co., Ltd. | Procede de carbonitruration sous vide |
Family Cites Families (6)
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FR1159878A (fr) | 1956-10-17 | 1958-07-03 | Treuil destiné particulièrement à être monté sur un véhicule automobile | |
US5273585A (en) * | 1990-03-27 | 1993-12-28 | Mazda Motor Corporation | Heat-treating apparatus |
JP2006002194A (ja) * | 2004-06-16 | 2006-01-05 | Nsk Ltd | 軸の製造方法 |
JP4655528B2 (ja) * | 2004-07-12 | 2011-03-23 | 日産自動車株式会社 | 高強度機械構造用部品の製造方法、および高強度機械構造用部品 |
FR2884523B1 (fr) * | 2005-04-19 | 2008-01-11 | Const Mecaniques Sa Et | Procede et four de carbonitruration a basse pression |
DE102010028165A1 (de) * | 2010-04-23 | 2011-10-27 | Robert Bosch Gmbh | Verfahren zur Carbonitrierung von metallischen Bauteilen |
-
2011
- 2011-10-31 FR FR1159878A patent/FR2981949B1/fr not_active Expired - Fee Related
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2012
- 2012-10-08 EP EP12772768.3A patent/EP2773789B1/fr active Active
- 2012-10-08 US US14/354,393 patent/US9938615B2/en active Active
- 2012-10-08 IN IN3955CHN2014 patent/IN2014CN03955A/en unknown
- 2012-10-08 WO PCT/EP2012/069890 patent/WO2013064337A1/fr active Application Filing
- 2012-10-08 CN CN201280053988.7A patent/CN103958720B/zh active Active
- 2012-10-08 JP JP2014539275A patent/JP6138810B2/ja active Active
- 2012-10-08 MX MX2014005221A patent/MX357137B/es active IP Right Grant
- 2012-10-08 KR KR1020147015027A patent/KR101945005B1/ko active IP Right Grant
- 2012-10-08 BR BR112014010316A patent/BR112014010316A2/pt active Search and Examination
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
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EP1454998A1 (fr) * | 2001-12-13 | 2004-09-08 | Koyo Thermo Systems Co., Ltd. | Procede de carbonitruration sous vide |
Also Published As
Publication number | Publication date |
---|---|
MX2014005221A (es) | 2015-03-09 |
WO2013064337A1 (fr) | 2013-05-10 |
CN103958720B (zh) | 2016-05-18 |
US9938615B2 (en) | 2018-04-10 |
KR101945005B1 (ko) | 2019-02-01 |
JP6138810B2 (ja) | 2017-05-31 |
EP2773789A1 (fr) | 2014-09-10 |
CN103958720A (zh) | 2014-07-30 |
FR2981949A1 (fr) | 2013-05-03 |
BR112014010316A2 (pt) | 2017-05-02 |
IN2014CN03955A (fr) | 2015-10-23 |
FR2981949B1 (fr) | 2013-11-08 |
US20140290800A1 (en) | 2014-10-02 |
KR20140101750A (ko) | 2014-08-20 |
JP2014532810A (ja) | 2014-12-08 |
MX357137B (es) | 2018-06-27 |
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