EP2773789B1 - Carbonitriding method having a final nitridation step during temperature decrease - Google Patents
Carbonitriding method having a final nitridation step during temperature decrease 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
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- 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
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
- C23C8/24—Nitriding
- C23C8/26—Nitriding of ferrous surfaces
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
- C23C8/34—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases more than one element being applied in more than one step
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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
- C23C8/80—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
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.The present invention relates to a process for carbonitriding steel parts, including, but not limited to, parts used in the manufacture of motor vehicles. In particular the invention also applies to parts used in the manufacture of agricultural machinery, machine tool, or parts in the aeronautical field.
On connaît du document
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.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.
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.In order to achieve this object, it is proposed according to the invention a carbonitriding process of steel parts, especially parts used in the manufacture of motor vehicles, according to claim 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.Indeed, according to a finding that is already part of the invention, it was observed that it was possible to start the quenching from a temperature lower than the carburizing temperature. A lowering of temperature during the last nitriding step therefore makes it possible to perform this under conditions more favorable to good nitriding.
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.According to an advantageous version of the invention, the final nitriding step comprises a temperature step. The last nitriding step is thus carried out under optimal conditions.
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.Preferably, during the initial nitriding phase the temperature rise is carried out with a reduced temperature gradient compared to the simple temperature rise phase. Thus, without increasing the duration of the treatment, 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.
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.Other features and advantages of the invention will become apparent on reading the following description of various nonlimiting particular embodiments of the low pressure carbonitriding process according to the invention, with reference to the 3 appended figures which are diagrams. schematics illustrating the various steps of the method according to the invention according to different embodiments.
En référence à la
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.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. In practice 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.
Dans l'exemple de réalisation de la
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.In a manner known per se, the initial nitriding phase comprises injection phases of a nitriding gas such as alternating ammonia with diffusion phases.
Selon un deuxième mode de réalisation de la phase de nitruration initiale, illustré par la
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.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.
Selon un troisième mode de réalisation de la phase de nitruration initiale, illustré à l'aide de la
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.Whatever the embodiment used for the initial nitriding phase, the process then comprises n alternating cementation phases with nitriding phases. In a manner known per se, the carburizing and nitriding steps comprise alternating treatment gas injection phases with diffusion phases not shown in the figures. In the figure, the diagram has been interrupted between the nitriding step N1 and the last cementation step Cn. At the end of this last cementation step Cn, the process comprises a final nitriding step Nn accompanied by a descent of temperature immediately before T quenching.
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.According to a first embodiment of the last nitriding step Nn, illustrated by a dashed line in the figure, the temperature is lowered continuously to a temperature within the optimum temperature range for all nitriding. remaining high enough to allow efficient quenching. In the example illustrated, the final temperature before quenching is 840 ° C. In practice results satisfactory are obtained for a final temperature before quenching between 900 ° C and 800 ° C. It has been found that this limited descent of temperature decreases the stress on the parts during quenching.
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.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. As for the initial nitriding phase, the final nitriding step preferably comprises alternating nitriding gas injection phases with diffusion phases.
Selon un second mode de réalisation de la dernière étape de nitruration Nn, illustré à la
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.In practice, 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.
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.It will be noted that because of the increased efficiency of the nitriding phases according to the invention it is possible to replace at least one nitriding step between two carburizing steps by a simple diffusion step. Such a step is shorter than a nitriding step so that the total duration of the treatment is shortened.
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.Naturally, the invention is not limited to the embodiments described and variations can be made without departing from the scope of the invention as defined by the claims. In particular, the initial rise in temperature can be carried out according to a constant gradient as illustrated by a dashed line in the 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.It will be noted that because of the increased efficiency of the nitriding phases according to the invention it is possible to replace at least one nitriding step between two carburizing steps by a simple diffusion step. Such a step is shorter than a nitriding step so that the total duration of the treatment is shortened.
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.Naturally, the invention is not limited to the embodiments described and variations can be made without departing from the scope of the invention as defined by the claims. In particular, the initial rise in temperature can be carried out according to a constant gradient as illustrated by a dashed line in the figure.
Claims (6)
- Method for carbonitriding steel parts, in particular parts entering into the production of motor vehicles, having alternate cementation (C1-Cn) and nitridation (N1-Nn-1) steps at a constant temperature, preceded by a temperature increasing step, and followed by a soaking step (T), characterised in that it has a final nitridation step (Nn) accompanied by a fall in temperature immediately before the soaking (T), in that the fall in temperature is achieved up to a temperature of between 900°C and 800°C, in that the fall in temperature is achieved with a temperature gradient of between 10°C/min and 1°C/min and in that the temperature increasing step comprises one single temperature increasing phase (M) followed by an initial nitridation phase (Ni) with a continued increase in temperature and the initial nitridation phase (Ni) is carried out from a temperature of between 700°C and 750°C, and up to a temperature of between 860°C and 1000°C.
- Carbonitriding method according to claim 1, characterised in that the final nitridation step has a temperature bearing (Nn2).
- Carbonitriding method according to claim 1, characterised in that during the initial nitridation phase (N1), the increase in temperature is achieved with a reduced temperature gradient with respect to the single temperature increasing phase (M).
- Carbonitriding method according to claim 3, characterised in that the initial nitridation phase (N1) has a temperature bearing (Ni2-Ni3).
- Carbonitriding method according to claim 3, characterised in that the initial nitridation phase (N1) is immediately followed by a first cementation step (C1).
- Carbonitriding method according to claim 1, characterised in that the initial nitridation phase (N1) is carried out with a temperature gradient of between 3.5°C/min and 10°C/min.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1159878A FR2981949B1 (en) | 2011-10-31 | 2011-10-31 | PROCESS FOR CARBONITURING AT FINAL NITRIDATION STEP DURING TEMPERATURE DESCENT |
PCT/EP2012/069890 WO2013064337A1 (en) | 2011-10-31 | 2012-10-08 | Carbonitriding method having a final nitridation step during temperature decrease |
Publications (2)
Publication Number | Publication Date |
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EP2773789A1 EP2773789A1 (en) | 2014-09-10 |
EP2773789B1 true EP2773789B1 (en) | 2019-02-20 |
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EP12772768.3A Active EP2773789B1 (en) | 2011-10-31 | 2012-10-08 | Carbonitriding method having a final nitridation step during temperature decrease |
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Country | Link |
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US (1) | US9938615B2 (en) |
EP (1) | EP2773789B1 (en) |
JP (1) | JP6138810B2 (en) |
KR (1) | KR101945005B1 (en) |
CN (1) | CN103958720B (en) |
BR (1) | BR112014010316A2 (en) |
FR (1) | FR2981949B1 (en) |
IN (1) | IN2014CN03955A (en) |
MX (1) | MX357137B (en) |
WO (1) | WO2013064337A1 (en) |
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FR3028530B1 (en) * | 2014-11-14 | 2020-10-23 | Peugeot Citroen Automobiles Sa | PROCESS AND PLANT FOR CARBONITRURING STEEL PART (S) UNDER LOW PRESSURE AND HIGH TEMPERATURE |
KR20220074308A (en) | 2020-11-27 | 2022-06-03 | 시흥시 | Manufacturing method of functional Nelumbinis semen tea |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1454998A1 (en) * | 2001-12-13 | 2004-09-08 | Koyo Thermo Systems Co., Ltd. | Vacuum carbo-nitriding method |
Family Cites Families (6)
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FR1159878A (en) | 1956-10-17 | 1958-07-03 | Winch particularly intended to be mounted on a motor vehicle | |
US5273585A (en) * | 1990-03-27 | 1993-12-28 | Mazda Motor Corporation | Heat-treating apparatus |
JP2006002194A (en) * | 2004-06-16 | 2006-01-05 | Nsk Ltd | Method for manufacturing shaft |
JP4655528B2 (en) * | 2004-07-12 | 2011-03-23 | 日産自動車株式会社 | Manufacturing method of high-strength machine structure parts and high-strength machine structure parts |
FR2884523B1 (en) * | 2005-04-19 | 2008-01-11 | Const Mecaniques Sa Et | LOW PRESSURE CARBONITRUTING PROCESS AND FURNACE |
DE102010028165A1 (en) * | 2010-04-23 | 2011-10-27 | Robert Bosch Gmbh | Process for the carbonitriding of metallic components |
-
2011
- 2011-10-31 FR FR1159878A patent/FR2981949B1/en not_active Expired - Fee Related
-
2012
- 2012-10-08 MX MX2014005221A patent/MX357137B/en active IP Right Grant
- 2012-10-08 US US14/354,393 patent/US9938615B2/en active Active
- 2012-10-08 WO PCT/EP2012/069890 patent/WO2013064337A1/en active Application Filing
- 2012-10-08 CN CN201280053988.7A patent/CN103958720B/en active Active
- 2012-10-08 KR KR1020147015027A patent/KR101945005B1/en active IP Right Grant
- 2012-10-08 JP JP2014539275A patent/JP6138810B2/en active Active
- 2012-10-08 IN IN3955CHN2014 patent/IN2014CN03955A/en unknown
- 2012-10-08 EP EP12772768.3A patent/EP2773789B1/en active Active
- 2012-10-08 BR BR112014010316A patent/BR112014010316A2/en active Search and Examination
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1454998A1 (en) * | 2001-12-13 | 2004-09-08 | Koyo Thermo Systems Co., Ltd. | Vacuum carbo-nitriding method |
Also Published As
Publication number | Publication date |
---|---|
IN2014CN03955A (en) | 2015-10-23 |
EP2773789A1 (en) | 2014-09-10 |
JP2014532810A (en) | 2014-12-08 |
JP6138810B2 (en) | 2017-05-31 |
MX357137B (en) | 2018-06-27 |
KR20140101750A (en) | 2014-08-20 |
US20140290800A1 (en) | 2014-10-02 |
MX2014005221A (en) | 2015-03-09 |
US9938615B2 (en) | 2018-04-10 |
KR101945005B1 (en) | 2019-02-01 |
BR112014010316A2 (en) | 2017-05-02 |
FR2981949A1 (en) | 2013-05-03 |
WO2013064337A1 (en) | 2013-05-10 |
FR2981949B1 (en) | 2013-11-08 |
CN103958720A (en) | 2014-07-30 |
CN103958720B (en) | 2016-05-18 |
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