EP3237648B1 - Method for surface treatment of a steel component by nitriding or nitrocarburising, oxidising and then impregnating - Google Patents

Method for surface treatment of a steel component by nitriding or nitrocarburising, oxidising and then impregnating Download PDF

Info

Publication number
EP3237648B1
EP3237648B1 EP15821125.0A EP15821125A EP3237648B1 EP 3237648 B1 EP3237648 B1 EP 3237648B1 EP 15821125 A EP15821125 A EP 15821125A EP 3237648 B1 EP3237648 B1 EP 3237648B1
Authority
EP
European Patent Office
Prior art keywords
carried out
nitriding
minutes
impregnation
treatment
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
EP15821125.0A
Other languages
German (de)
French (fr)
Other versions
EP3237648A1 (en
Inventor
Pierre-Louis MAGDINIER
Marie-Noëlle DESBOUCHE-JANNY
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.)
Hydromecanique et Frottement SAS
Original Assignee
HEF SAS
Hydromecanique et Frottement SAS
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 HEF SAS, Hydromecanique et Frottement SAS filed Critical HEF SAS
Priority to PL15821125T priority Critical patent/PL3237648T3/en
Priority to SI201531209T priority patent/SI3237648T1/en
Publication of EP3237648A1 publication Critical patent/EP3237648A1/en
Application granted granted Critical
Publication of EP3237648B1 publication Critical patent/EP3237648B1/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
    • C23C8/80—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/06—Surface hardening
    • 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
    • C23C8/34—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
    • C23C8/40—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 liquids, e.g. salt baths, liquid suspensions
    • C23C8/58—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 liquids, e.g. salt baths, liquid suspensions more than one element being applied in more than one step

Definitions

  • the invention relates to a method of surface treatment of a piece of ferrous metal, in practice made of alloyed steel or not, having good resistance to corrosion by virtue of an impregnation treatment and a piece of steel having a high resistance to wear and corrosion which is dry to the touch.
  • the invention applies to all types of mechanical parts intended to provide a mechanical function in service and having to have a high hardness, a long resistance to corrosion and wear. This is for example the case of many parts used in the automotive or aeronautical field.
  • nitriding and nitrocarburizing are thermochemical treatments of nitrogen supply (nitrogen and carbon respectively) by combination-diffusion: there is formed on the surface a combination layer formed of iron nitrides (there are several possible phases), under which nitrogen is present by diffusion.
  • the Applicant has itself proposed treatment methods aimed at obtaining even better corrosion resistance.
  • oxidizing so as to obtain a nitrided layer comprising a deep and compact sublayer and a surface layer of well controlled porosity and finally to the deposition of a polymer of thickness between 3 and 20 ⁇ m, made of fluoroethylene-propylene (FEP) ), or even polytetrafluoroethylene (PTFE), or even polymers or copolymers of fluorinated or silicone polyurethanes, or polyamides-polyimides.
  • FEP fluoroethylene-propylene
  • PTFE polytetrafluoroethylene
  • BS salt spray
  • the parts are preferably nitrided in baths of molten salts based on cyanate ions then oxidized and finally impregnated with a hydrophobic wax.
  • Nitriding followed by oxidation leads to the formation of a layer consisting of a compact deep sub-layer and a surface layer whose porosity is well controlled.
  • the impregnation wax is an organic compound with a high molecular weight of between 500 and 10,000 and of surface tension, in the liquid state, of between 10 and 73 mN / m.
  • the contact angle between the solid phase and the surface layer and the wax in the liquid state is between 0 and 75 degrees.
  • the wax is chosen from natural waxes, synthetic polyethylene, polypropylene, polyesters, fluorinated waxes or modified petroleum residues.
  • This solution simultaneously improves the corrosion resistance and friction properties of ferrous metal parts.
  • the parts thus treated have good corrosion resistance in standard salt spray combined with good friction properties.
  • the patent EP - 0 560 641 describes a process for phosphating steel parts to improve the resistance to corrosion and wear, making it possible to obtain specific surface characteristics resulting from a phosphating treatment preceded by a nitriding operation in a bath of molten salts containing sulfur species, from a nitriding operation in a bath of molten salts followed by a conventional sulfurization treatment, or from a metal deposit followed by a conventional sulfurization operation.
  • the corrosion resistance values of the parts thus treated, after exposure to salt spray are of the order of 900 to 1200 hours.
  • the patent EP - 1,180,552 relates to a method of surface treatment of mechanical parts subjected to both wear and corrosion by having a roughness conducive to good lubrication and according to which nitriding is carried out by immersion between 500 ° C and 700 ° C parts in a nitriding bath of molten salts containing alkaline cyanates and carbonates in precise ranges but free of species sulfur, then an oxidation is carried out in an aqueous oxidizing solution below 200 ° C.
  • the document WO2012 / 146839 targeted a nitriding treatment leading to an appropriate roughness without requiring a finishing treatment; he described a bath of molten salts for nitriding mechanical steel parts having specific contents of alkali metal chloride, alkali metal carbonate, alkali metal cyanate and cyanide ions.
  • the corrosion resistance measured in salt spray was between 240 and 650 hours.
  • finishing treatment deposit of a varnish or of a wax, or phosphating treatment
  • nitriding or nitrocarburizing treatment oxidation of mechanical parts made of ferrous material
  • certain finishing treatments result in the fact that the surface of the parts thus treated tends to transfer a little oil onto the surfaces with which it can come into contact and tends to collect dust. the surrounding environment; this is hardly compatible with an additional step such as overmolding.
  • the object of the invention is to remedy these drawbacks in a simple, safe, efficient and rational manner, while achieving very high levels of resistance to corrosion and to wear, better than with baths. current impregnation.
  • the impregnation in a bath in accordance with the invention leads to a substantial improvement in corrosion resistance compared to a conventional bath, based on oils, acids and ethanol.
  • the parts are dry to the touch (this is understood to mean the absence of oil transfer to an antagonistic surface), hence the absence of tendency to pick up surrounding dust and the ability to undergo post-treatment such as overmolding.
  • a part according to the invention obtained by the process of the invention, namely a steel part having a high resistance to wear and corrosion, comprising a combination layer. at least 8 micrometers, a layer of oxides of thickness between 0.1 and 3 micrometers and an impregnation layer which is dry to the touch.
  • ambient temperature does not designate a precise temperature but the fact that the treatment is done without temperature control (it is therefore neither necessary to heat the bath nor to cool it), and that it can be do at the temperature induced by the environment, even if it varies in proportions that can be significant during the year, for example between 15 ° C and 50 ° C.
  • the nitriding / nitrocarburizing step is carried out so that the thickness of the combination layer obtained is at least 10 micrometers.
  • the synthetic phenolic additive is a compound of formula C 15 H 24 0.
  • the impregnation bath further comprises at least one additive chosen from the group consisting of calcium or sodium sulfonate, phosphites, diphenylamines, zinc dithiophosphate, nitrites, phosphoramides.
  • the content of such additives is advantageously at most equal to 5%.
  • the bath is preferably formed from 90% +/- 0.5% by weight of solvent, 10% +/- 0.5% by weight of paraffin oils and between 0.01% and not more of 1% +/- 0.1% of synthetic phenolic additive of formula C 15 H 24 O.
  • the impregnation is carried out by soaking for a period of approximately 15 minutes.
  • This soaking step is advantageously followed by a natural or accelerated drying operation by steaming.
  • the nitriding / nitrocarburizing step is carried out in a bath of molten salts containing from 14% to 44% by weight of alkaline cyanates at a temperature of 550 ° C to 650 ° C for at least 45 minutes; preferably, this nitriding / nitrocarburizing bath contains from 14% to 18% by weight of alkaline cyanates.
  • this treatment is carried out at a temperature of 590 ° C for 90 minutes to 100 minutes; according to a variant, also advantageous, the nitriding / nitrocarburizing treatment in salt baths melted is carried out at a temperature of 630 ° C for about 45 minutes to 50 minutes.
  • the nitriding / nitrocarburizing step is carried out in a gaseous medium between 500 ° C and 600 ° C containing ammonia.
  • the nitriding / nitrocarburizing step is carried out in an ionic medium (plasma) in a medium comprising at least nitrogen and hydrogen under reduced pressure.
  • the oxidation step is carried out in a bath of molten salts containing carbonates, nitrates and alkali hydroxides.
  • the molten oxidation salt bath contains alkaline nitrates, alkali carbonates and alkali hydroxides.
  • the oxidation step is carried out at a temperature of 430 ° C to 470 ° C for 15 to 20 minutes.
  • the oxidation is carried out in an aqueous bath containing alkali hydroxides, alkaline nitrates and alkaline nitrites.
  • the oxidation step it is advantageous for the oxidation step to be carried out at a temperature of 110 ° C to 130 ° C for 15 to 20 minutes.
  • the oxidation step is carried out in a gaseous medium mainly consisting of water vapor, at a temperature of 450 ° C. to 550 ° C. for 30 to 120 minutes.
  • these tests were carried out by combining several types of nitriding or nitrocarburizing treatments, known per se, several types of oxidation treatment, known per se, and several types of impregnation. These tests were carried out on ferrous metal parts with smooth areas and sharp edges. More particularly, tests were carried out on grooved axes in annealed and rectified XC45 steel, having a smooth bearing and a threaded bearing.
  • NITRU1 to NITRU3 treatments in molten salt baths.
  • EP - 1,180,552 with: * the NITRU1 treatment located in the preferred low temperature range and the preferred average treatment time (from 45 minutes to 50 minutes), * the NITRU2 treatment located in the same preferred low temperature range but with the maximum treatment time (outside the preferred zone, ie from 90 minutes to 100 minutes) and * the NITRU3 treatment located in the preferred high temperature range with the preferred average treatment time (45 minutes to 50 minutes).
  • the parameters of these treatments are summarized in the table below.
  • the NITRU1 treatment results in a combination layer of thickness less than 8 micrometers
  • the NITRU2 and NITRU3 treatments result in a layer whose thickness exceeds this threshold, and is preferably even at least 10 micrometers. In practice, it seems unnecessary to seek to exceed 25 micrometers, so that an effective range for the thickness of the layer appears to be 10 to 25 micrometers.
  • these three treatments correspond to a treatment in a bath of molten salts containing from 14% to 44% by weight of alkaline cyanates (preferably from 14% to 18%) at a temperature of 550 ° C to 650 ° C (preferably from 590 ° C to 630 ° C) for at least 45 minutes (it does not seem useful to exceed 120 minutes, even 90 minutes).
  • NITRU4 a gaseous medium
  • NITRU5 a conventional treatment in ionic medium (plasma), NITRU5 (targeting a thickness of combination layer of at least 8 ⁇ m and advantageously between 10 and 25 ⁇ m).
  • the NITRU4 treatment in a gaseous medium was carried out in an oven between approximately 500 and 600 ° C. under a controlled atmosphere comprising ammonia.
  • the processing time has been established to guarantee a combination layer thickness of at least 8 micrometers, preferably greater than 10 micrometers.
  • the NITRU5 treatment it was carried out in an ionic medium (plasma) in a mixture comprising at least nitrogen and hydrogen, under reduced pressure (that is to say under a pressure below atmospheric pressure , typically less than 0.1 atmosphere).
  • the processing time has also been established to guarantee a combination layer thickness of at least 8 micrometers, preferably at least 10 micrometers.
  • the thickness of the treatment layer indicated does not take into account the diffusion layer (for nitrogen as well as for carbon).
  • Oxidations Ox1 and Ox2 correspond substantially, respectively, to the oxidation in salt bath and to the aqueous oxidation of the document EP1180552 cited above, while the nitrocarburizing (NITRU5) and Ox3 oxidation treatment parameters, in an ionized medium, correspond substantially to Example 9 of the document EP0497663 .
  • the oxidations were carried out so as to obtain oxidation layers of thickness between 0.1 and 3 micrometers.
  • impregnation treatment 1 did not induce dimensional variation.
  • the surface of the parts was dry to the touch; this implies that, on the one hand, the surface of these parts does not tend to collect dust and that, on the other hand, these parts are compatible with an after-treatment such as overmolding.
  • NITRU 1 NITRU 2 NITRU 3 NITRU 4 NITRU 5 Treatment 1 Ox1 + Imp2 96h 360h 912h 792h 384h 72h Treatment 2 Ox1 + lmp1 96h 960h 1368h 1368h 1008h 576h Treatment 3 Ox2 + lmp2 96h 312h 576h 792h 504h 72h Treatment 4 Ox2 + lmp1 96h 360h 1056h 1056h 720h 360h Treatment 5 Ox3 + lmp2 96h 192h 456h 552h 312h 24h Treatment 6 Ox3 + lmp1 96h 264h 888h 792h 552h 72h Treatment 7 Ox0 + Imp2 96h 96h 456h 384h 48h 48h Treatment 8 Ox0 + Imp1 96h 120h 504h 624h 360h 336h
  • the oxidation-impregnation treatment does not matter when there is no nitriding / nitrocarburizing (the corrosion resistance remains at 96 h, in the first column).
  • the increase in corrosion resistance is at least of the order of 200 hours.
  • the new impregnation results in an increase in the corrosion resistance of the order of 300 hours; in the case of NITRU5 combined with oxidation in an ionic liquid medium (oxidation 1 - treatments 1 and 2), the increase is even of the order of 500 hours.
  • the improvement in corrosion resistance is, for type 2 and 3 oxidations (treatments 3 to 6) of at least 250 hours for the NITRU3 treatment and even 450 hours for the treatment NITRU2. With type 2 oxidation (treatments 3 and 4) corrosion resistance exceeding the threshold of 1000 hours is obtained.
  • the impregnation bath 1 has a surprising synergistic effect with the nitriding / nitrocarburizing treatments NITRU2 and NITRU3 provided that the nitriding / nitrocarburizing is followed by a type 1 or 2 oxidation. , an optimum seems to be obtained when the oxidation treatment is type 1.
  • the particular composition of the impregnation bath considered in the tests falls into a more general composition, namely a bath formed of at least 70% by weight, to within 1%, of a solvent formed of a mixture of hydrocarbons formed from a cut of C9 to C17 alkanes, from 10% to 30% by weight, to within 1%, of at least one paraffin oil composed of a cut of C16 to C32 alkanes and of minus an additive of the synthetic phenolic additive type at a concentration of between 0.01% and 3% by weight, at room temperature.
  • the solvent content is preferably between 80% and 90% by weight; likewise, the content of paraffin oil is preferably between 10% and 20% by weight.
  • the cut of alkanes in the solvent is preferably from C9 to C14.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Chemical Treatment Of Metals (AREA)

Description

L'invention concerne un procédé de traitement superficiel d'une pièce en métal ferreux, en pratique en acier allié ou non, ayant une bonne tenue à la corrosion grâce à un traitement d'imprégnation et une pièce en acier ayant une résistance élevée à l'usure et à la corrosion qui est sèche au toucher.The invention relates to a method of surface treatment of a piece of ferrous metal, in practice made of alloyed steel or not, having good resistance to corrosion by virtue of an impregnation treatment and a piece of steel having a high resistance to wear and corrosion which is dry to the touch.

Plus généralement, l'invention s'applique à tout type de pièces mécaniques destinées à assurer en service une fonction mécanique et devant avoir une dureté importante, une longue résistance à la corrosion et à l'usure. C'est par exemple le cas de nombreuses pièces utilisées dans le domaine de l'automobile ou de l'aéronautique.More generally, the invention applies to all types of mechanical parts intended to provide a mechanical function in service and having to have a high hardness, a long resistance to corrosion and wear. This is for example the case of many parts used in the automotive or aeronautical field.

Pour améliorer la tenue à la corrosion de pièces mécaniques en acier, divers traitements ont été proposés, qui comportent une étape de nitruration ou de nitrocarburation (en bains de sels fondus, ou en milieu gazeux), parfois suivie d'une étape d'oxydation et/ou du dépôt d'une couche de finition. Il est rappelé que la nitruration et la nitrocarburation sont des traitements thermochimiques d'apport d'azote (respectivement d'azote et de carbone) par combinaison-diffusion : il se forme en surface une couche de combinaison formée de nitrures de fer (il existe plusieurs phases possibles), sous laquelle l'azote est présent par diffusion.To improve the corrosion resistance of mechanical steel parts, various treatments have been proposed, which include a nitriding or nitrocarburizing step (in molten salt baths, or in a gaseous medium), sometimes followed by an oxidation step. and / or depositing a top coat. It is recalled that nitriding and nitrocarburizing are thermochemical treatments of nitrogen supply (nitrogen and carbon respectively) by combination-diffusion: there is formed on the surface a combination layer formed of iron nitrides (there are several possible phases), under which nitrogen is present by diffusion.

Ainsi, le document EP- 0 053 521 a proposé, principalement pour des axes de piston dont on cherchait à améliorer la tenue à la corrosion et/ou le coefficient de frottement, un traitement de nitrocarburation adapté à former une couche de phase Epsilon et un traitement de finition consistant à recouvrir la couche en phase Epsilon d'une couche de finition formée d'une résine (le document mentionne une gamme très variée, englobant les résines acryliques, les alkydes, les esters maléiques, les époxy, les formaldéhydes, les phénoliques, le butyral-polyvinyle, les chlorures polyvinyle, les polyamides, les poly-imides, les polyuréthanes, les silicones, les éthers polyvinyle et les urée-formaldéhydes, avantageusement chargés en additifs choisis parmi les phosphates et les chromates de zinc (pour améliorer la résistance à la corrosion), et/ou du silicone, des cires, des poly-tétra-fluoro-éthylènes, du di-sulfite de molybdène, du graphite ou du stéarate de zinc (pour réduire le coefficient de frottement). Il n'y a pas de résultat précis ; il est simplement mentionné qu'un bon exemple est un système de résines acryliques/époxide/amino, contenant du chromate ou du stéarate de zinc ou une cire.So the document EP- 0 053 521 has proposed, mainly for piston pins of which it was sought to improve the resistance to corrosion and / or the coefficient of friction, a nitrocarburizing treatment suitable for forming an Epsilon phase layer and a finishing treatment consisting in covering the layer with Epsilon phase of a finishing layer formed of a resin (the document mentions a very varied range, including acrylic resins, alkyds, maleic esters, epoxies, formaldehydes, phenolics, butyral-polyvinyl, chlorides polyvinyl, polyamides, polyimides, polyurethanes, silicones, polyvinyl ethers and urea-formaldehydes, advantageously loaded with additives chosen from phosphates and zinc chromates (to improve resistance to corrosion), and / or silicone, waxes, poly-tetra-fluoro-ethylenes, molybdenum di-sulfite, graphite or zinc stearate (to reduce the coefficient of friction). There is no specific result; it is simply mentioned that a good example is a system of acrylic / epoxy / amino resins, containing chromate or zinc stearate or a wax.

Quant au document EP - 0 122 762 , il décrit un procédé de fabrication de pièces d'acier résistant à la corrosion, comprenant des étapes de nitruration (en phase Epsilon, comme précédemment), puis d'oxydation par voie gazeuse, puis d'application de matière cireuse (Castrol V425) contenant des hydrocarbures aliphatiques et des savons métalliques du groupe 2a, de préférence des savons au calcium et/ou au baryum. La tenue à la corrosion en brouillard salin a été de l'ordre de 250 heures.As for the document EP - 0 122 762 , it describes a method of manufacturing corrosion-resistant steel parts, comprising nitriding steps (in the Epsilon phase, as before), then gaseous oxidation, then application of waxy material (Castrol V425) containing aliphatic hydrocarbons and group 2a metallic soaps, preferably calcium and / or barium soaps. The corrosion resistance in salt spray was of the order of 250 hours.

La Demanderesse a elle-même proposé des procédés de traitements visant à obtenir des tenues encore meilleures à la corrosion.The Applicant has itself proposed treatment methods aimed at obtaining even better corrosion resistance.

Dans le document EP - 0 497 663 , elle a proposé un procédé consistant à soumettre des pièces en métal ferreux à une nitruration, typiquement en un bain de sels fondus constitué de cyanates et de sodium, potassium et lithium, puis à une oxydation en bains de sels fondus ou dans une atmosphère ionisante oxydante, en sorte d'obtenir une couche nitrurée comprenant une sous-couche profonde et compacte et une couche superficielle de porosité bien contrôlée et enfin au dépôt d'un polymère d'épaisseur comprise entre 3 et 20 µm, en fluoroéthylène-propylène (FEP), voire en polytetrafluoroéthylène, (PTFE), voire en polymères ou copolymères de polyuréthanes fluorés ou siliconés, ou en polyamides-polyimides. Avec ce procédé, des essais ont montré que la résistance à la corrosion était améliorée en permettant d'obtenir une exposition au brouillard salin (BS) pouvant aller de 500 à 1000 heures environ sans qu'apparaisse une manifestation de corrosion.In the document EP - 0 497 663 , it proposed a method consisting in subjecting ferrous metal parts to nitriding, typically in a bath of molten salts consisting of cyanates and of sodium, potassium and lithium, then to an oxidation in baths of molten salts or in an ionizing atmosphere. oxidizing, so as to obtain a nitrided layer comprising a deep and compact sublayer and a surface layer of well controlled porosity and finally to the deposition of a polymer of thickness between 3 and 20 μm, made of fluoroethylene-propylene (FEP) ), or even polytetrafluoroethylene (PTFE), or even polymers or copolymers of fluorinated or silicone polyurethanes, or polyamides-polyimides. With this process, tests have shown that the corrosion resistance is improved by making it possible to obtain exposure to salt spray (BS) which can range from 500 to 1000 hours approximately without any appearance of corrosion appearing.

Ensuite, par le document EP - 0 524 037 , il a été proposé un procédé de traitement selon lequel les pièces sont nitrurées de préférence en bains de sels fondus à base d'ions cyanates puis oxydées et enfin imprégnées d'une cire hydrophobe. La nitruration suivie de l'oxydation conduit à la formation d'une couche constituée d'une sous-couche profonde compacte et d'une couche superficielle dont la porosité est bien contrôlée. La cire d'imprégnation est un composé organique à haut poids moléculaire compris entre 500 et 10000 et de tension superficielle, à l'état liquide, comprise entre 10 et 73 mN/m. L'angle de contact entre la phase solide et la couche superficielle et la cire à l'état liquide, est compris entre 0 et 75 degrés. Plus précisément, la cire est choisie parmi les cires naturelles, les cires synthétiques polyéthylènes, polypropylènes, polyesters, fluorés ou bien résidus pétroliers modifiés. Cette solution permet d'améliorer simultanément la résistance à la corrosion et les propriétés de friction des pièces en métal ferreux. Les pièces ainsi traitées ont une bonne résistance à la corrosion en brouillard salin normalisé combinée à de bonnes propriétés de friction.Then by the document EP - 0 524 037 , a treatment method has been proposed according to which the parts are preferably nitrided in baths of molten salts based on cyanate ions then oxidized and finally impregnated with a hydrophobic wax. Nitriding followed by oxidation leads to the formation of a layer consisting of a compact deep sub-layer and a surface layer whose porosity is well controlled. The impregnation wax is an organic compound with a high molecular weight of between 500 and 10,000 and of surface tension, in the liquid state, of between 10 and 73 mN / m. The contact angle between the solid phase and the surface layer and the wax in the liquid state is between 0 and 75 degrees. More specifically, the wax is chosen from natural waxes, synthetic polyethylene, polypropylene, polyesters, fluorinated waxes or modified petroleum residues. This solution simultaneously improves the corrosion resistance and friction properties of ferrous metal parts. The parts thus treated have good corrosion resistance in standard salt spray combined with good friction properties.

Le brevet EP - 0 560 641 décrit un procédé de phosphatation de pièces en acier pour améliorer la résistance à la corrosion et à l'usure permettant d'obtenir des caractéristiques spécifiques de surface résultant d'un traitement de phosphatation précédé d'une opération de nitruration dans un bain de sels fondus contenant des espèces soufrées, d'une opération de nitruration dans un bain de sels fondus suivie d'un traitement classique de sulfuration, ou d'un dépôt de métal suivi d'une opération classique de sulfuration. Les valeurs de résistance à la corrosion des pièces ainsi traitées, après exposition au brouillard salin, sont de l'ordre de 900 à 1200 heures.The patent EP - 0 560 641 describes a process for phosphating steel parts to improve the resistance to corrosion and wear, making it possible to obtain specific surface characteristics resulting from a phosphating treatment preceded by a nitriding operation in a bath of molten salts containing sulfur species, from a nitriding operation in a bath of molten salts followed by a conventional sulfurization treatment, or from a metal deposit followed by a conventional sulfurization operation. The corrosion resistance values of the parts thus treated, after exposure to salt spray, are of the order of 900 to 1200 hours.

Le brevet EP - 1 180 552 concerne un procédé de traitement superficiel de pièces mécaniques soumises à la fois à l'usure et à la corrosion en ayant une rugosité propice à une bonne lubrification et selon lequel une nitruration est mise en œuvre par immersion entre 500°C et 700°C des pièces dans un bain de nitruration de sels fondus contenant des cyanates et carbonates alcalins dans des gammes précises mais exempt d'espèces soufrées, puis une oxydation est mise en œuvre dans une solution aqueuse oxydante en dessous de 200°C.The patent EP - 1,180,552 relates to a method of surface treatment of mechanical parts subjected to both wear and corrosion by having a roughness conducive to good lubrication and according to which nitriding is carried out by immersion between 500 ° C and 700 ° C parts in a nitriding bath of molten salts containing alkaline cyanates and carbonates in precise ranges but free of species sulfur, then an oxidation is carried out in an aqueous oxidizing solution below 200 ° C.

Le document WO2012/146839 a visé un traitement de nitruration conduisant à une rugosité appropriée sans nécessiter de traitement de finition ; il a décrit un bain de sels fondus pour la nitruration de pièces mécaniques en acier présentant des teneurs spécifiques en chlorure de métal alcalin, en carbonate de métal alcalin, en cyanate de métal alcalin et en ions cyanures. La résistance à la corrosion mesurée en brouillard salin a été comprise entre 240 et 650 heures.The document WO2012 / 146839 targeted a nitriding treatment leading to an appropriate roughness without requiring a finishing treatment; he described a bath of molten salts for nitriding mechanical steel parts having specific contents of alkali metal chloride, alkali metal carbonate, alkali metal cyanate and cyanide ions. The corrosion resistance measured in salt spray was between 240 and 650 hours.

Il est à noter que le fait d'ajouter un traitement de finition (dépôt d'un vernis ou d'une cire, ou traitement de phosphatation) à un traitement de nitruration ou de nitrocarburation puis d'oxydation de pièces mécaniques en matériau ferreux permet souvent d'améliorer la résistance à la corrosion, mais en impliquant généralement une surcote compliquant l'obtention, en fin de traitement, des cotes dimensionnelles souhaitées. A titre subsidiaire, il a été constaté que certains traitements de finition se traduisent par le fait que la surface des pièces ainsi traitées tend à transférer un peu d'huile sur les surfaces avec lesquelles elle peut venir en contact et a tendance à capter la poussière du milieu environnant ; cela est difficilement compatible avec une étape complémentaire telle qu'un surmoulage.It should be noted that the fact of adding a finishing treatment (deposit of a varnish or of a wax, or phosphating treatment) to a nitriding or nitrocarburizing treatment then of oxidation of mechanical parts made of ferrous material allows often to improve the resistance to corrosion, but generally involving an additional cost, making it difficult to obtain the desired dimensional dimensions at the end of the treatment. In the alternative, it has been found that certain finishing treatments result in the fact that the surface of the parts thus treated tends to transfer a little oil onto the surfaces with which it can come into contact and tends to collect dust. the surrounding environment; this is hardly compatible with an additional step such as overmolding.

L'invention s'est fixée pour but de remédier à ces inconvénients de manière simple, sure, efficace et rationnelle, tout en atteignant des niveaux très élevés de résistance à la corrosion ainsi qu'à l'usure, meilleurs qu'avec les bains d'imprégnation actuels.The object of the invention is to remedy these drawbacks in a simple, safe, efficient and rational manner, while achieving very high levels of resistance to corrosion and to wear, better than with baths. current impregnation.

Pour résoudre un tel problème, il a été conçu et mis au point un procédé de traitement superficiel d'une pièce mécanique en acier pour lui conférer une résistance élevée à l'usure et à la corrosion comportant :

  • une étape de nitruration ou de nitrocarburation adaptée à former une couche de combinaison d'au moins 8 micromètres d'épaisseur formée de nitrures de fer de phases ε et/ou γ',
  • une étape d'oxydation adaptée à générer une couche d'oxydes d'épaisseur comprise entre 0.1 micromètre et 3 micromètres et
  • une étape d'imprégnation par trempage dans un bain d'imprégnation pendant au moins 5 minutes, ce bain étant formé d'au moins 70% en poids, à 1% près, d'un solvant formé d'un mélange d'hydrocarbures formé d'une coupe d'alcanes de C9 à C17, de 10% à 30% en poids, à 1% près, d'au moins une huile de paraffine composée d'une coupe d'alcanes C16 à C32 et d'au moins un additif du type additif phénolique de synthèse à une concentration comprise entre 0.01% et 3% en poids, à 0.1% près, à la température ambiante.
To solve such a problem, a method of surface treatment of a mechanical steel part has been designed and developed to give it a high resistance to wear and corrosion comprising:
  • a nitriding or nitrocarburizing step suitable for forming a combination layer at least 8 micrometers thick formed of iron nitrides of phases ε and / or γ ',
  • an oxidation step suitable for generating an oxide layer of thickness between 0.1 micrometer and 3 micrometers and
  • an impregnation step by soaking in an impregnation bath for at least 5 minutes, this bath being formed of at least 70% by weight, to within 1%, of a solvent formed from a mixture of hydrocarbons formed a cut of C9 to C17 alkanes, from 10% to 30% by weight, to within 1%, of at least one paraffin oil composed of a cut of C16 to C32 alkanes and of at least an additive of the synthetic phenolic additive type at a concentration of between 0.01% and 3% by weight, to the nearest 0.1%, at room temperature.

Il est apparu que, sous réserve que la nitruration ou la nitrocarburation et l'oxydation aient été effectuées de manière suffisamment efficace pour former les couches définies ci-dessus, l'imprégnation dans un bain conforme à l'invention conduit à une amélioration substantielle de la résistance à la corrosion par rapport à un bain classique, à base d'huiles, d'acides et d'éthanol. En outre il a été constaté que, après le traitement d'imprégnation, les pièces sont sèches au toucher (on entend par là l'absence de transfert d'huile sur une surface antagoniste), d'où l'absence de tendance à capter la poussière environnante et l'aptitude à subir un post-traitement tel qu'un surmoulage.It appeared that, provided that the nitriding or the nitrocarburization and the oxidation were carried out sufficiently effectively to form the layers defined above, the impregnation in a bath in accordance with the invention leads to a substantial improvement in corrosion resistance compared to a conventional bath, based on oils, acids and ethanol. In addition, it has been observed that, after the impregnation treatment, the parts are dry to the touch (this is understood to mean the absence of oil transfer to an antagonistic surface), hence the absence of tendency to pick up surrounding dust and the ability to undergo post-treatment such as overmolding.

C'est ainsi qu'on peut reconnaître une pièce conforme à l'invention, obtenue par le procédé de l'invention, à savoir une pièce en acier ayant une résistance élevée à l'usure et à la corrosion, comportant une couche de combinaison d'au moins 8 micromètres, une couche d'oxydes d'épaisseur comprise entre 0.1 et 3 micromètres et une couche d'imprégnation qui est sèche au toucher.This is how we can recognize a part according to the invention, obtained by the process of the invention, namely a steel part having a high resistance to wear and corrosion, comprising a combination layer. at least 8 micrometers, a layer of oxides of thickness between 0.1 and 3 micrometers and an impregnation layer which is dry to the touch.

La notion de température ambiante ne désigne pas une température précise mais le fait que le traitement se fait sans contrôle de la température (il n'est donc nécessaire ni de chauffer le bain ni de le refroidir), et qu'elle peut se faire à la température induite par l'environnement, même si elle varie dans des proportions pouvant être importantes au cours de l'année, par exemple entre 15°C et 50°C.The concept of ambient temperature does not designate a precise temperature but the fact that the treatment is done without temperature control (it is therefore neither necessary to heat the bath nor to cool it), and that it can be do at the temperature induced by the environment, even if it varies in proportions that can be significant during the year, for example between 15 ° C and 50 ° C.

De manière préférée, l'étape de nitruration/nitrocarburation est conduite de manière à ce que l'épaisseur de la couche de combinaison obtenue est d'au moins 10 micromètres.Preferably, the nitriding / nitrocarburizing step is carried out so that the thickness of the combination layer obtained is at least 10 micrometers.

De manière avantageuse, l'additif phénolique de synthèse est un composé de formule C15H240.Advantageously, the synthetic phenolic additive is a compound of formula C 15 H 24 0.

De manière également avantageuse, le bain d'imprégnation comporte en outre au moins un additif choisi dans le groupe constitué par le sulfonate de calcium ou de sodium, les phosphites, les diphénylamines, le dithiophosphate de zinc, les nitrites, les phosphoramides. La teneur en de tels additifs est avantageusement au plus égale à 5%.Also advantageously, the impregnation bath further comprises at least one additive chosen from the group consisting of calcium or sodium sulfonate, phosphites, diphenylamines, zinc dithiophosphate, nitrites, phosphoramides. The content of such additives is advantageously at most equal to 5%.

Plus particulièrement, le bain est, de manière préférée, formé de 90%+/-0,5% en poids de solvant, 10% +/-0,5% en poids d'huiles de paraffine et entre 0.01% et pas plus de 1%+/-0.1% d'additif phénolique de synthèse de formule C15H24O.More particularly, the bath is preferably formed from 90% +/- 0.5% by weight of solvent, 10% +/- 0.5% by weight of paraffin oils and between 0.01% and not more of 1% +/- 0.1% of synthetic phenolic additive of formula C 15 H 24 O.

De manière avantageuse, l'imprégnation s'effectue par trempage pendant une durée d'environ 15 minutes.Advantageously, the impregnation is carried out by soaking for a period of approximately 15 minutes.

Cette étape de trempage est avantageusement suivie d'une opération de séchage naturel ou accéléré par étuvage.This soaking step is advantageously followed by a natural or accelerated drying operation by steaming.

Selon une première option avantageuse, l'étape de nitruration/nitrocarburation est effectuée en un bain de sels fondus contenant de 14% à 44% en poids de cyanates alcalins à une température de 550°C à 650°C pendant au moins 45 minutes ; de préférence, ce bain de nitruration/nitrocarburation contient de 14% à 18% en poids de cyanates alcalins. De manière avantageuse, ce traitement est effectué à une température de 590°C pendant 90 minutes à 100 minutes ; selon une variante, également avantageuse, le traitement de nitruration/nitrocarburation en bains de sels fondus est effectué à une température de 630°C pendant environ 45 minutes à 50 minutes.According to a first advantageous option, the nitriding / nitrocarburizing step is carried out in a bath of molten salts containing from 14% to 44% by weight of alkaline cyanates at a temperature of 550 ° C to 650 ° C for at least 45 minutes; preferably, this nitriding / nitrocarburizing bath contains from 14% to 18% by weight of alkaline cyanates. Advantageously, this treatment is carried out at a temperature of 590 ° C for 90 minutes to 100 minutes; according to a variant, also advantageous, the nitriding / nitrocarburizing treatment in salt baths melted is carried out at a temperature of 630 ° C for about 45 minutes to 50 minutes.

Selon une seconde option avantageuse, l'étape de nitruration/nitrocarburation est effectuée en un milieu gazeux entre 500°C et 600°C contenant de l'ammoniac.According to a second advantageous option, the nitriding / nitrocarburizing step is carried out in a gaseous medium between 500 ° C and 600 ° C containing ammonia.

Selon une troisième option avantageuse, l'étape de nitruration/nitrocarburation est effectuée en milieu ionique (plasma) dans un milieu comprenant au moins de l'azote et de l'hydrogène sous pression réduite.According to a third advantageous option, the nitriding / nitrocarburizing step is carried out in an ionic medium (plasma) in a medium comprising at least nitrogen and hydrogen under reduced pressure.

De manière avantageuse, l'étape d'oxydation est effectuée dans un bain de sels fondus contenant des carbonates, des nitrates et des hydroxydes alcalins.Advantageously, the oxidation step is carried out in a bath of molten salts containing carbonates, nitrates and alkali hydroxides.

Selon une option particulièrement intéressante, le bain de sels fondus d'oxydation contient des nitrates alcalins, des carbonates alcalins et des hydroxydes alcalins. Dans ce cas, il est avantageux que l'étape d'oxydation soit réalisée à une température de 430°C à 470°C pendant de 15 à 20 minutes.According to a particularly interesting option, the molten oxidation salt bath contains alkaline nitrates, alkali carbonates and alkali hydroxides. In this case, it is advantageous that the oxidation step is carried out at a temperature of 430 ° C to 470 ° C for 15 to 20 minutes.

Selon une autre option intéressante, l'oxydation est conduite dans un bain aqueux contenant des hydroxydes alcalins, des nitrates alcalins et des nitrites alcalins. Dans ce cas, il est avantageux que l'étape d'oxydation soit réalisée à une température de 110°C à 130°C pendant de 15 à 20 minutes.According to another interesting option, the oxidation is carried out in an aqueous bath containing alkali hydroxides, alkaline nitrates and alkaline nitrites. In this case, it is advantageous for the oxidation step to be carried out at a temperature of 110 ° C to 130 ° C for 15 to 20 minutes.

En variante, l'étape d'oxydation est effectuée en un milieu gazeux majoritairement constitué de vapeur d'eau, à une température de 450°C à 550°C pendant de 30 à 120 minutes.As a variant, the oxidation step is carried out in a gaseous medium mainly consisting of water vapor, at a temperature of 450 ° C. to 550 ° C. for 30 to 120 minutes.

Ces diverses préférences ressortent de divers essais qui ont été effectués, à titre d'exemple illustratif non limitatif.These various preferences emerge from various tests which have been carried out, by way of nonlimiting illustrative example.

Plus précisément, ces essais ont été effectués en combinant plusieurs types de traitements de nitruration ou nitrocarburation, connus en soi, plusieurs types de traitement d'oxydation, connus en soi, et plusieurs types d'imprégnation. Ces essais ont été effectués sur des pièces en métal ferreux présentant des zones lisses et des arêtes vives. Plus particulièrement, des essais ont été effectués sur des axes cannelés en acier XC45 recuit et rectifié, présentant une portée lisse et une portée filetée.More specifically, these tests were carried out by combining several types of nitriding or nitrocarburizing treatments, known per se, several types of oxidation treatment, known per se, and several types of impregnation. These tests were carried out on ferrous metal parts with smooth areas and sharp edges. More particularly, tests were carried out on grooved axes in annealed and rectified XC45 steel, having a smooth bearing and a threaded bearing.

Au total, cinq traitements de nitruration ou de nitrocarburation ont été testés. Trois de ces traitements sont des traitements en bains de sels fondus, NITRU1 à NITRU3, qui correspondent à des exemples de nitrocarburation conformes au traitement de nitrocarburation enseigné par le document EP - 1 180 552 avec :
* le traitement NITRU1 situé en fourchette basse de température préférée et le temps moyen préféré de traitement (de 45 minutes à 50 minutes),
* le traitement NITRU2 situé en cette même fourchette basse de température préférée mais avec le temps de traitement maximum (en dehors de la zone préférée, soit de 90 minutes à 100 minutes) et
* le traitement NITRU3 situé en fourchette haute de température préférée avec le temps moyen préféré de traitement (45 minutes à 50 minutes). Les paramètres de ces traitements sont récapitulés dans le tableau ci-dessous. Teneur en CN- en % (en poids) Teneur en CNO- en % (en poids) Température (en °C) Temps de traitement(en minutes) Epaisseur de couche de traitement (en micromètres) NITRU 1 1 à 3 14 à 18 590 >=45 <8 NITRU 2 1 à 3 14 à 18 590 >= 90 >8 NITRU 3 1 à 3 14 à 18 630 >= 45 >8 A total of five nitriding or nitrocarburizing treatments were tested. Three of these treatments are treatments in molten salt baths, NITRU1 to NITRU3, which correspond to examples of nitrocarburization in accordance with the nitrocarburization treatment taught by the document. EP - 1,180,552 with:
* the NITRU1 treatment located in the preferred low temperature range and the preferred average treatment time (from 45 minutes to 50 minutes),
* the NITRU2 treatment located in the same preferred low temperature range but with the maximum treatment time (outside the preferred zone, ie from 90 minutes to 100 minutes) and
* the NITRU3 treatment located in the preferred high temperature range with the preferred average treatment time (45 minutes to 50 minutes). The parameters of these treatments are summarized in the table below. CN content - in% (by weight) NOC content - in% (by weight) Temperature (in ° C) Processing time (in minutes) Treatment layer thickness (in micrometers) NITRU 1 1 to 3 14 to 18 590 > = 45 <8 NITRU 2 1 to 3 14 to 18 590 > = 90 > 8 NITRU 3 1 to 3 14 to 18 630 > = 45 > 8

Plus généralement, on peut noter que le traitement NITRU1 conduit à une couche de combinaison d'épaisseur inférieure à 8 micromètres, tandis que les traitements NITRU2 et NITRU3 conduisent à une couche dont l'épaisseur dépasse ce seuil, et soit même de préférence d'au moins 10 micromètres. Il semble inutile, en pratique, de chercher à dépasser 25 micromètres, de sorte qu'une plage efficace pour l'épaisseur de la couche semble être de 10 à 25 micromètres.More generally, it can be noted that the NITRU1 treatment results in a combination layer of thickness less than 8 micrometers, while the NITRU2 and NITRU3 treatments result in a layer whose thickness exceeds this threshold, and is preferably even at least 10 micrometers. In practice, it seems unnecessary to seek to exceed 25 micrometers, so that an effective range for the thickness of the layer appears to be 10 to 25 micrometers.

De manière générale, ces trois traitements correspondent à un traitement en un bain de sels fondus contenant de 14% à 44% en poids de cyanates alcalins (de préférence de 14% à 18%) à une température de 550°C à 650°C (de préférence, de 590°C à 630°C) pendant au moins 45 minutes (il ne semble pas utile de dépasser 120 minutes, voire 90 minutes).Generally, these three treatments correspond to a treatment in a bath of molten salts containing from 14% to 44% by weight of alkaline cyanates (preferably from 14% to 18%) at a temperature of 550 ° C to 650 ° C (preferably from 590 ° C to 630 ° C) for at least 45 minutes (it does not seem useful to exceed 120 minutes, even 90 minutes).

Un autre de ces traitements est un traitement classique en milieu gazeux, NITRU4 (en visant une épaisseur de couche de combinaison d'au moins 8 µm et avantageusement comprise entre 10 et 25 µm), et un autre de ces traitements est un traitement classique en milieu ionique (plasma), NITRU5 (en visant une épaisseur de couche de combinaison d'au moins 8 µm et avantageusement comprise entre 10 et 25 µm).Another of these treatments is a conventional treatment in a gaseous medium, NITRU4 (by targeting a thickness of combination layer of at least 8 μm and advantageously between 10 and 25 μm), and another of these treatments is a conventional treatment in ionic medium (plasma), NITRU5 (targeting a thickness of combination layer of at least 8 μm and advantageously between 10 and 25 μm).

Plus précisément, le traitement NITRU4 en milieu gazeux a été effectué dans un four entre environ 500 et 600°C sous atmosphère contrôlée comprenant de l'ammoniac. Le temps de traitement a été établi pour garantir une épaisseur de couche de combinaison d'au moins 8 micromètres, de préférence supérieure à 10 micromètres.More specifically, the NITRU4 treatment in a gaseous medium was carried out in an oven between approximately 500 and 600 ° C. under a controlled atmosphere comprising ammonia. The processing time has been established to guarantee a combination layer thickness of at least 8 micrometers, preferably greater than 10 micrometers.

Quant au traitement NITRU5, il a été effectué en milieu ionique (plasma) dans un mélange comprenant au moins de l'azote et de l'hydrogène, sous pression réduite (c'est-à-dire sous une pression inférieure à la pression atmosphérique, typiquement moins de 0.1 atmosphère). Le temps de traitement a également été établi pour garantir une épaisseur de couche de combinaison d'au moins 8 micromètres, de préférence d'au moins 10 micromètres.As for the NITRU5 treatment, it was carried out in an ionic medium (plasma) in a mixture comprising at least nitrogen and hydrogen, under reduced pressure (that is to say under a pressure below atmospheric pressure , typically less than 0.1 atmosphere). The processing time has also been established to guarantee a combination layer thickness of at least 8 micrometers, preferably at least 10 micrometers.

Dans ce qui précède, l'épaisseur de couche de traitement indiquée ne tient pas compte de la couche de diffusion (pour l'azote ainsi que pour le carbone).In the above, the thickness of the treatment layer indicated does not take into account the diffusion layer (for nitrogen as well as for carbon).

Selon ces divers traitements de nitruration/nitrocarburation, on a obtenu différentes couches de combinaison :

  • soit des nitrures en phase ε (Fe2-3N), soit des nitrures en phases ε et Y' (Fe2-3N + Fe4N) avec les bains de sels NITRU1 à NITRU3,
  • des nitrures en phases ε et Y' (Fe2-3N + Fe4N) avec le traitement en phase gazeuse NITRU4,
  • des nitrures en phases ε et Y' (Fe2-3N + Fe4N) avec le traitement en phase plasma NITRU5.
According to these various nitriding / nitrocarburizing treatments, different layers of combination were obtained:
  • either nitrides in phase ε (Fe 2-3 N), or nitrides in phases ε and Y '(Fe 2-3 N + Fe 4 N) with the salt baths NITRU1 to NITRU3,
  • nitrides in phases ε and Y '(Fe 2-3 N + Fe 4 N) with the treatment in the gas phase NITRU4,
  • nitrides in phases ε and Y '(Fe 2-3 N + Fe 4 N) with the treatment in plasma phase NITRU5.

Seuls les traitements NITRU2 à NITRU5 ont abouti à des épaisseurs de couche de combinaison d'au moins 8 micromètres, avantageusement entre 10 et 25 micromètres.Only the NITRU2 to NITRU5 treatments resulted in thicknesses of the combination layer of at least 8 micrometers, advantageously between 10 and 25 micrometers.

Pour chacun des 5 traitements de nitruration NITRU1 à NITRU5, trois types de traitements d'oxydation ont été mis en œuvre :

  1. 1) Oxydation « type 1 » (ou Ox1), c'est-à-dire en milieu liquide ionique contenant du NaNO3 (entre 35 et 40% en poids), des carbonates (de Li, de K, de Na) (entre 15 et 20% en poids), du NaOH (entre 40 et 45% en poids) - température de 450°C - temps de traitement de 15 minutes.
  2. 2) Oxydation « type 2 » (ou Ox2, c'est-à-dire en milieu aqueux contenant du KOH (entre 80% et 85% en poids, du NaNO3 (entre 10% et 15% en poids et du NaNO2 (entre 1 et 6% en poids - température de 120°C - temps de traitement de 15 minutes.
  3. 3) Oxydation « type 3 » (ou Ox3) en milieu gazeux (traitement en vapeur d'eau) - température de 500°C - temps de traitement de 60 minutes.
For each of the 5 nitriding treatments NITRU1 to NITRU5, three types of oxidation treatments have been implemented:
  1. 1) “Type 1” (or Ox1) oxidation, that is to say in an ionic liquid medium containing NaNO3 (between 35 and 40% by weight), carbonates (of Li, K, Na) (between 15 and 20% by weight), NaOH (between 40 and 45% by weight) - temperature of 450 ° C - treatment time of 15 minutes.
  2. 2) "Type 2" oxidation (or Ox2, that is to say in an aqueous medium containing KOH (between 80% and 85% by weight, NaNO3 (between 10% and 15% by weight and NaNO2 (between 1 and 6% by weight - temperature of 120 ° C - treatment time of 15 minutes.
  3. 3) “Type 3” (or Ox3) oxidation in a gaseous medium (water vapor treatment) - temperature of 500 ° C - treatment time of 60 minutes.

Les oxydations Ox1 et Ox2 correspondent sensiblement, respectivement, à l'oxydation en bain de sel et à l'oxydation aqueuse du document EP1180552 précité, alors que les paramètres de traitements de nitrocarburation (NITRU5) et d'oxydation Ox3, en milieu ionisé, correspondent sensiblement à l'exemple 9 du document EP0497663 .Oxidations Ox1 and Ox2 correspond substantially, respectively, to the oxidation in salt bath and to the aqueous oxidation of the document EP1180552 cited above, while the nitrocarburizing (NITRU5) and Ox3 oxidation treatment parameters, in an ionized medium, correspond substantially to Example 9 of the document EP0497663 .

Les oxydations ont été effectuées en sorte d'obtenir des couches d'oxydation d'épaisseur comprises entre 0.1 et 3 micromètres.The oxidations were carried out so as to obtain oxidation layers of thickness between 0.1 and 3 micrometers.

Enfin, après l'opération d'oxydation, deux types d'imprégnation ont été réalisés :

  1. 1) une imprégnation nouvelle dite « imprégnation 1» (ou Imp1) dans un bain contenant principalement un solvant (90%+/-0.5% en poids) formé d'un mélange d'hydrocarbures composé d'une coupe d'alcanes de C9 à C17, 10% +/-0.5% en poids d'une huile de paraffine composée d'une coupe d'alcanes C16 à C32 et entre 0.1% et 1% +/-0.1% d'un additif phénolique de synthèse de formule C15H24O. Cette imprégnation a été réalisée par trempage pendant environ 15 minutes d'immersion, suivie d'un séchage naturel ou accéléré par étuvage.
  2. 2) Une imprégnation classique dite « imprégnation 2 » (ou Imp2), dans un bain contenant principalement des huiles (entre 60 et 85% en poids), des acides (entre 6 et 15% en poids) et de l'éthanol (entre 1 et 5% en poids). Cette imprégnation a été réalisée par trempage pendant environ 15 minutes d'immersion, suivi d'un séchage naturel ou accéléré par étuvage.
Finally, after the oxidation operation, two types of impregnation were carried out:
  1. 1) a new impregnation known as “impregnation 1” (or Imp1) in a bath containing mainly a solvent (90% +/- 0.5% by weight) formed of a mixture of hydrocarbons composed of a cut of C9 alkanes at C17, 10% +/- 0.5% by weight of a paraffin oil composed of a cut of alkanes C16 to C32 and between 0.1% and 1% +/- 0.1% of a synthetic phenolic additive of formula C 15 H 24 O. This impregnation was carried out by soaking for about 15 minutes of immersion, followed by natural or accelerated drying by steaming.
  2. 2) A conventional impregnation known as “impregnation 2” (or Imp2), in a bath containing mainly oils (between 60 and 85% by weight), acids (between 6 and 15% by weight) and ethanol (between 1 and 5% by weight). This impregnation was carried out by soaking for approximately 15 minutes of immersion, followed by natural or accelerated drying by steaming.

En combinant les types d'oxydation et les types d'imprégnation, on a défini 8 traitements, notés 1 à 8, conformément au tableau suivant (on y désigne une absence d'oxydation par « Ox0 »). Type d'oxydation Type d'imprégnation Traitement 1 Ox1 Imp2 Traitement 2 Ox1 Imp1 Traitement 3 Ox2 Imp2 Traitement 4 Ox2 Imp1 Traitement 5 Ox3 Imp2 Traitement 6 Ox3 Imp1 Traitement 7 Sans oxydation (Ox0) Imp2 Traitement 8 Sans oxydation (Ox0) Imp1 By combining the types of oxidation and the types of impregnation, 8 treatments have been defined, denoted 1 to 8, in accordance with the following table (there is an absence of oxidation by "Ox0"). Type of oxidation Type of impregnation Treatment 1 Ox1 Imp2 Treatment 2 Ox1 Imp1 Treatment 3 Ox2 Imp2 Treatment 4 Ox2 Imp1 Treatment 5 Ox3 Imp2 Treatment 6 Ox3 Imp1 Treatment 7 Without oxidation (Ox0) Imp2 Treatment 8 Without oxidation (Ox0) Imp1

Des échantillons ont été préparés en combinant ces traitements 1 à 8 avec les traitements de nitruration/nitrocarburation précités. Des essais de tenue à la corrosion ont été effectués selon la norme ISO 9227 (2006) en brouillard salin. Les résultats sont résumés dans le tableau ci-dessous. Pour chaque essai, un minimum de 10 pièces a été testé. Le temps (indiqué en heures) correspond à une absence totale de trace de corrosion sur 100% des pièces.Samples were prepared by combining these treatments 1 to 8 with the aforementioned nitriding / nitrocarburizing treatments. Corrosion resistance tests have been carried out according to ISO 9227 (2006) in salt spray. The results are summarized in the table below. For each test, a minimum of 10 pieces was tested. The time (indicated in hours) corresponds to a total absence of any trace of corrosion on 100% of the parts.

Il est apparu que le traitement d'imprégnation 1 n'induisait pas de variation dimensionnelle. De surcroît, la surface des pièces était sèche au toucher ; cela implique que, d'une part, la surface de ces pièces n'a pas tendance à capter la poussière et que, d'autre part, ces pièces sont compatibles avec un post-traitement tel qu'un surmoulage. Sans Nitruration NITRU 1 NITRU 2 NITRU 3 NITRU 4 NITRU 5 Traitement 1 Ox1+Imp2 96h 360h 912h 792h 384h 72h Traitement 2 Ox1+lmp1 96h 960h 1368h 1368h 1008h 576h Traitement 3 Ox2+lmp2 96h 312h 576h 792h 504h 72h Traitement 4 Ox2+lmp1 96h 360h 1056h 1056h 720h 360h Traitement 5 Ox3+lmp2 96h 192h 456h 552h 312h 24h Traitement 6 Ox3+lmp1 96h 264h 888h 792h 552h 72h Traitement 7 Ox0+Imp2 96h 96h 456h 384h 48h 48h Traitement 8 Ox0+Imp1 96h 120h 504h 624h 360h 336h It appeared that the impregnation treatment 1 did not induce dimensional variation. In addition, the surface of the parts was dry to the touch; this implies that, on the one hand, the surface of these parts does not tend to collect dust and that, on the other hand, these parts are compatible with an after-treatment such as overmolding. Without Nitriding NITRU 1 NITRU 2 NITRU 3 NITRU 4 NITRU 5 Treatment 1 Ox1 + Imp2 96h 360h 912h 792h 384h 72h Treatment 2 Ox1 + lmp1 96h 960h 1368h 1368h 1008h 576h Treatment 3 Ox2 + lmp2 96h 312h 576h 792h 504h 72h Treatment 4 Ox2 + lmp1 96h 360h 1056h 1056h 720h 360h Treatment 5 Ox3 + lmp2 96h 192h 456h 552h 312h 24h Treatment 6 Ox3 + lmp1 96h 264h 888h 792h 552h 72h Treatment 7 Ox0 + Imp2 96h 96h 456h 384h 48h 48h Treatment 8 Ox0 + Imp1 96h 120h 504h 624h 360h 336h

Il ressort tout d'abord de ce tableau que le traitement nouveau d'imprégnation (imprégnation 1 - traitements pairs) apporte une amélioration sensible par rapport au cas d'une imprégnation classique (imprégnation 2 - traitements impairs).It first appears from this table that the new impregnation treatment (impregnation 1 - even treatments) brings a significant improvement compared to the case of a classic impregnation (impregnation 2 - odd treatments).

On peut noter que le traitement d'oxydation-imprégnation importe peu lorsqu'il n'y a pas de nitruration/nitrocarburation (la résistance à la corrosion reste à 96h, dans la première colonne).It can be noted that the oxidation-impregnation treatment does not matter when there is no nitriding / nitrocarburizing (the corrosion resistance remains at 96 h, in the first column).

Quant au traitement NITRU5, il tend à montrer que le traitement d'imprégnation 2 (classique) aboutit à une résistance à la corrosion inférieure au cas sans aucune nitruration.As for the NITRU5 treatment, it tends to show that the impregnation treatment 2 (conventional) results in a lower corrosion resistance than in the case without any nitriding.

L'intérêt de l'imprégnation de type 1 est notamment visible dans le cas de la nitrocarburation NITRU5 puisque, avec le cas de l'oxydation 3 (en milieu gazeux - traitements 5 et 6), l'amélioration est de l'ordre d'un triplement de la tenue à la corrosion (augmentation d'une cinquantaine d'heures) par rapport au cas d'une imprégnation classique ; il s'agit pourtant du cas où l'oxydation a un effet particulièrement négatif.The advantage of type 1 impregnation is particularly visible in the case of nitrocarburization NITRU5 since, with the case of oxidation 3 (in gaseous medium - treatments 5 and 6), the improvement is of the order of '' a threefold increase in corrosion resistance (increase of around fifty hours) compared to the case of conventional impregnation; however, this is the case where oxidation has a particularly negative effect.

Dans tous les autres cas NITRU5, l'augmentation de tenue à la corrosion est d'au moins de l'ordre de 200 heures. Ainsi, dans le cas de la NITRU5 combinée avec l'oxydation en milieu aqueux (oxydation 2 - traitements 3 et 4) ou en l'absence d'oxydation (traitements 7 et 8), l'imprégnation nouvelle aboutit à une augmentation de la tenue à la corrosion de l'ordre de 300 heures ; dans le cas de la NITRU5 combinée avec l'oxydation en milieu liquide ionique (oxydation 1 - traitements 1 et 2), l'augmentation est même de l'ordre de 500 heures.In all other NITRU5 cases, the increase in corrosion resistance is at least of the order of 200 hours. Thus, in the case of NITRU5 combined with oxidation in an aqueous medium (oxidation 2 - treatments 3 and 4) or in the absence of oxidation (treatments 7 and 8), the new impregnation results in an increase in the corrosion resistance of the order of 300 hours; in the case of NITRU5 combined with oxidation in an ionic liquid medium (oxidation 1 - treatments 1 and 2), the increase is even of the order of 500 hours.

En ce qui concerne le traitement NITRU1, on peut noter que l'effet bénéfique de l'imprégnation nouvelle existe mais est modéré, y compris en pourcentage, par rapport à l'imprégnation classique (traitements 3 à 8, même si les tenues à la corrosion, en valeur absolue, sont meilleures qu'avec NITRU5). Toutefois, on peut noter une augmentation très importante, de 600 heures, dans le cas d'une oxydation en milieu ionique (traitements 1 et 2), avec une tenue à la corrosion qui approche du seuil de 1000 heures. On croit pouvoir en déduire que la condition d'une couche de combinaison d'au moins 8 micromètres d'épaisseur peut être abaissé dans le cas d'une oxydation de type 1.With regard to the NITRU1 treatment, it can be noted that the beneficial effect of the new impregnation exists but is moderate, including in percentage, compared to the conventional impregnation (treatments 3 to 8, even if the outfits to the corrosion, in absolute value, are better than with NITRU5). However, we can note a very significant increase, of 600 hours, in the case of oxidation in an ionic medium (treatments 1 and 2), with corrosion resistance approaching the threshold of 1000 hours. It is believed to be able to deduce therefrom that the condition of a combination layer at least 8 micrometers thick can be lowered in the case of a type 1 oxidation.

Si l'on considère maintenant le traitement NITRU4, il conduit au même commentaire que le traitement NITRU5 en l'absence d'oxydation (traitements 7 et 8). Par contre on constate une augmentation d'au moins 200 heures de la tenue à la corrosion dans le cas des oxydations de type 2 (en milieu aqueux - traitements 3 et 4) et de type 3 (en milieu gazeux - traitements 5 et 6). On observe toutefois une augmentation tout à fait remarquable dans le cas d'une oxydation de type 1 (oxydation en milieu ionique à haute température - traitements 1 et 2), puisque la tenue à la corrosion est améliorée de près de 600 heures en dépassant le seuil de 1000 heures.If we now consider the NITRU4 treatment, it leads to the same comment as the NITRU5 treatment in the absence of oxidation (treatments 7 and 8). On the other hand, there is an increase of at least 200 hours in the corrosion resistance in the case of type 2 oxidations (in aqueous medium - treatments 3 and 4) and of type 3 (in gaseous medium - treatments 5 and 6) . However, there is a quite remarkable increase in the case of type 1 oxidation (oxidation in ionic medium at high temperature - treatments 1 and 2), since the corrosion resistance is improved by almost 600 hours by exceeding the threshold of 1000 hours.

Si l'on considère maintenant les traitements de nitruration/nitrocarburation en bains de sels fondus dans lesquels on a pris soin d'obtenir une couche de combinaison d'au moins 8 micromètres d'épaisseur (voire 10 micromètres), on constate que l'imprégnation nouvelle conduit à des niveaux particulièrement élevés de la tenue à la corrosion.If we now consider the nitriding / nitrocarburizing treatments in molten salt baths in which care has been taken to obtain a combination layer at least 8 micrometers thick (or even 10 micrometers), it can be seen that the new impregnation leads to particularly high levels of corrosion resistance.

Dans le cas d'une absence d'oxydation, l'imprégnation nouvelle apporte une amélioration, surtout significative dans le cas de NITRU3.In the case of an absence of oxidation, the new impregnation brings an improvement, especially significant in the case of NITRU3.

En présence d'une oxydation, l'amélioration de la tenue à la corrosion est, pour les oxydations de type 2 et 3 (traitements 3 à 6) d'au moins 250 heures pour le traitement NITRU3 et même de 450 heures pour le traitement NITRU2. Avec le type d'oxydation de type 2 (traitements 3 et 4) on obtient des tenues à la corrosion dépassant le seuil de 1000 heures.In the presence of an oxidation, the improvement in corrosion resistance is, for type 2 and 3 oxidations (treatments 3 to 6) of at least 250 hours for the NITRU3 treatment and even 450 hours for the treatment NITRU2. With type 2 oxidation (treatments 3 and 4) corrosion resistance exceeding the threshold of 1000 hours is obtained.

Avec l'oxydation de type 1 (traitements 1 et 2), l'augmentation apportée par l'imprégnation nouvelle est étonnamment élevée, puisqu'elle est de 456 heures pour NITRU2 et même de 576h pour NITRU3 pour atteindre un seuil particulièrement élevé, de l'ordre de 1370h.With type 1 oxidation (treatments 1 and 2), the increase brought by the new impregnation is surprisingly high, since it is 456 hours for NITRU2 and even 576h for NITRU3 to reach a particularly high threshold, around 1370h.

Ainsi, il apparaît que :

  • l'imprégnation nouvelle apporte une amélioration de la tenue à la corrosion par rapport à une imprégnation classique, quels que soient les traitements de nitruration/nitrocarburation et d'oxydation,
  • Cette amélioration est particulièrement notable et conduit à des valeurs de tenue à la corrosion particulièrement élevées pour les traitements de nitrocarburation en bains de sels conduisant à une couche de combinaison d'au moins 8 micromètres (NITRU2 et NITRU3), de préférence entre 10 et 25 micromètres,
  • Cette amélioration est particulièrement notable et conduit à des valeurs de tenue à la corrosion particulièrement élevées pour les nitrocarburations en bains de sels (NITRU1 à NITRU3) ou en phase gazeuse (NITRU4) dans le cas d'une oxydation en bains de sels fondus (type 1),
  • Cette amélioration aboutit à des niveaux particulièrement élevés de tenue à la corrosion en combinant les nitrocarburations en bains de sels conduisant à une couche d'au moins 8 micromètres d'épaisseur (NITRU2 et NITRU3) et une oxydation de type 1 ou 2, surtout dans le cas d'une oxydation en bains de sels (type 1).
Thus, it appears that:
  • the new impregnation brings an improvement in the corrosion resistance compared to a conventional impregnation, whatever the nitriding / nitrocarburizing and oxidation treatments,
  • This improvement is particularly notable and leads to particularly high corrosion resistance values for nitrocarburizing treatments in salt baths leading to a combination layer of at least 8 micrometers (NITRU2 and NITRU3), preferably between 10 and 25 micrometers,
  • This improvement is particularly noticeable and leads to particularly high corrosion resistance values for nitrocarburations in salt baths (NITRU1 to NITRU3) or in the gas phase (NITRU4) in the case of oxidation in molten salt baths (type 1),
  • This improvement results in particularly high levels of corrosion resistance by combining nitrocarburations in salt baths leading to a layer at least 8 micrometers thick (NITRU2 and NITRU3) and a type 1 or 2 oxidation, especially in the case of oxidation in salt baths (type 1).

Les résultats ci-dessus ont été mesurés sur des zones lisses des échantillons.The above results were measured on smooth areas of the samples.

Des mesures sur des zones présentant des aspérités (des zones filetées en l'occurrence) ont également montré que les meilleurs résultats sont obtenus avec les traitements d'oxydation en milieu liquide 1 et 2, combinés avec une imprégnation de type 1 et avec une nitrocarburation en bains de sels conduisant à des couches de combinaison d'au moins 8 micromètres, NITRU2 et NITRU3.Measurements on areas with roughness (threaded areas in this case) have also shown that the best results are obtained with oxidation treatments in liquid medium 1 and 2, combined with type 1 impregnation and with nitrocarburization. in salt baths leading to combination layers of at least 8 micrometers, NITRU2 and NITRU3.

Alors que l'imprégnation nouvelle aboutit à des résultats excellents, équivalents pour NITRU2 et NITRU3, avec les oxydations en milieu liquide, sur des surfaces lisses, il semble que, sur les zones non lisses, l'imprégnation nouvelle donne de très bons résultats pour ces deux mêmes types de nitrocarburation, un peu meilleurs avec NITRU3 qu'avec NITRU2.While the new impregnation leads to excellent results, equivalent for NITRU2 and NITRU3, with oxidations in liquid medium, on smooth surfaces, it seems that, on the non-smooth areas, the new impregnation gives very good results for these same two types of nitrocarburizing, a little better with NITRU3 than with NITRU2.

En résumé, les résultats ci-dessus montrent que le bain d'imprégnation 1 présente un effet surprenant de synergie avec les traitements de nitruration/nitrocarburation NITRU2 et NITRU3 sous réserve que la nitruration/nitrocarburation soit suivie d'une oxydation de type 1 ou 2, un optimum semblant être obtenu lorsque le traitement d'oxydation est de type 1.In summary, the above results show that the impregnation bath 1 has a surprising synergistic effect with the nitriding / nitrocarburizing treatments NITRU2 and NITRU3 provided that the nitriding / nitrocarburizing is followed by a type 1 or 2 oxidation. , an optimum seems to be obtained when the oxidation treatment is type 1.

L'ampleur des augmentations de résistance à la corrosion constatées pour la combinaison du bain d'imprégnation 1 avec les traitements de nitruration/nitrocarburation en bains de sels fondus aboutissant à des couches de combinaison de plus de 8 micromètres d'épaisseur (NITRU2 et NITRU3) et le traitement d'oxydation 1 en bain de sels fondus traduit l'existence d'une synergie surprenante entre ces trois types de traitement qui reste incomprise.The scale of the increases in corrosion resistance observed for the combination of impregnation bath 1 with nitriding / nitrocarburizing treatments in molten salt baths resulting in combination layers of more than 8 micrometers thick (NITRU2 and NITRU3 ) and the oxidation treatment 1 in a bath of molten salts reflects the existence of a surprising synergy between these three types of treatment which remains misunderstood.

La composition particulière du bain d'imprégnation considérée dans les essais rentre dans une composition plus générale, à savoir un bain formé d'au moins 70% en poids, à 1% près, d'un solvant formé d'un mélange d'hydrocarbures formé d'une coupe d'alcanes de C9 à C17, de 10% à 30% en poids, à 1% près, d'au moins une huile de paraffine composée d'une coupe d'alcanes C16 à C32 et d'au moins un additif du type additif phénolique de synthèse à une concentration comprise entre 0.01% et 3% en poids, à la température ambiante.The particular composition of the impregnation bath considered in the tests falls into a more general composition, namely a bath formed of at least 70% by weight, to within 1%, of a solvent formed of a mixture of hydrocarbons formed from a cut of C9 to C17 alkanes, from 10% to 30% by weight, to within 1%, of at least one paraffin oil composed of a cut of C16 to C32 alkanes and of minus an additive of the synthetic phenolic additive type at a concentration of between 0.01% and 3% by weight, at room temperature.

La teneur en solvant est de préférence comprise entre 80% et 90% en poids ; de même, la teneur en huile de paraffine est de préférence comprise entre 10% et 20% en poids. La coupe d'alcanes du solvant est de préférence de C9 à C14.The solvent content is preferably between 80% and 90% by weight; likewise, the content of paraffin oil is preferably between 10% and 20% by weight. The cut of alkanes in the solvent is preferably from C9 to C14.

Les résultats précités ont été obtenus sur la base d'échantillons d'acier XC45, mais il est à la portée de l'homme de métier d'adapter les paramètres de traitement en fonction du matériau utilisé, et suivre ainsi l'enseignement précité.The aforementioned results were obtained on the basis of XC45 steel samples, but it is within the reach of the skilled person to adapt the processing parameters according to the material used, and thus follow the above teaching.

Claims (25)

  1. A method of surface treatment of a steel part to give it a high resistance to wear and to corrosion comprising
    * a step of nitriding or of nitrocarburizing adapted to form a combination layer of at least 8 micrometers thickness formed of iron nitrides of ε and/or γ' phases,
    * an oxidizing step adapted to generate a layer of oxides of thickness comprised between 0.1 and 3 micrometers and
    * a step of impregnating by steeping in an impregnation bath for at least 5 minutes, said bath being formed of at least 70% by weight, to the nearest 1%, of a solvent formed of a mixture of hydrocarbons formed of a set of alkanes from C9 to C17, of 10% to 30% by weight, to the nearest 1%, of at least one paraffin oil composed of a set of alkanes from C16 to C32 and of at least one additive of synthetic phenolic additive type at a concentration comprised between 0.01% and 3% by weight, to the nearest 0.1%, at ambient temperature.
  2. A method according to claim 1, characterized in that the synthetic phenolic additive is a compound of formula C15H24O.
  3. A method according to claim 2, characterized in that the impregnation bath is formed of 90%+/-0.5% by weight of solvent, 10% +/-0.5% by weight of paraffin oils and less than 1%+/-0.1%, of synthetic phenolic additive of formula C15H24O.
  4. A method according to any one of claims 1 to 3, characterized in that the impregnation bath further comprises at least one additive chosen from the group constituted by calcium or sodium sulfonate, phosphites, diphenylamines, zinc dithiophosphate, nitrites, phosphoramides.
  5. A method according to any one of claims 1 to 4, characterized in that the steeping operation is followed by an operation of natural drying or drying that is accelerated by baking.
  6. A method according to any one of claims 1 to 5, characterized in that the nitriding or nitrocarburizing step is carried out in a bath of molten salts containing from 14% to 44% by weight of alkali metal cyanates at a temperature of 550°C to 650°C for at least 45 minutes.
  7. A method according to claim 6, characterized in that the nitriding/nitrocarburizing bath contains from 14% to 18% by weight of alkali cyanates
  8. A method according to claim 6 or claim 7 characterized in that the nitriding/nitrocarburizing treatment is carried out at a temperature of 590°C for 90 minutes to 100 minutes.
  9. A method according to claim 6 or claim 7 characterized in that the nitriding/nitrocarburizing treatment is carried out at a temperature of 630°C for approximately 45 minutes to 50 minutes.
  10. A method according to any one of claims 1 to 5, characterized in that the nitrocarburizing step is carried out in a gaseous medium between 500°C and 600°C containing ammonia.
  11. A method according to any one of claims 1 to 5, characterized in that the nitriding or nitrocarburizing step is carried out in an ionic medium forming a plasma, comprising at least nitrogen and hydrogen at low pressure.
  12. A method according to any one of claims 1 to 11, characterized in that the nitriding or nitrocarburizing step is carried out so as to form a combination layer of thickness at least 10 micrometers.
  13. A method according to any one of claims 1 to 12, characterized in that the oxidizing step is carried out in a bath of molten salts which contains alkali metal nitrates, alkali carbonates and alkali hydroxides.
  14. A method according to claim 13, characterized in that the oxidizing step is carried out at a temperature of 430°C to 470°C for 15 to 20 minutes.
  15. A method according to any one of claims 1 to 12, characterized in that the oxidizing step is carried out in an aqueous bath which contains alkali hydroxides, alkali nitrates and alkali nitrites.
  16. A method according to claim 15, characterized in that the oxidizing step is carried out at a temperature of 110°C to 130°C for 15 to 20 minutes.
  17. A method according to any one of claims 1 to 12, characterized in that the oxidizing step is carried out in a gaseous medium for the most part constituted by water vapor, at a temperature of 450° to 550° for 30 to 120 minutes.
  18. A steel part having a high resistance to wear and to corrosion obtained by the method of any one of claims 1 to 17, comprising a combination layer of at least 8 micrometers, a layer of oxides of thickness comprised between 0.1 and 3 micrometers and an impregnation layer which is dry to the touch.
  19. A steel part according to claim 18, characterized in that the combination layer is formed of iron nitrides of ε and/or γ' phases.
  20. A steel part according to claim 18 or 19, characterized in that the combination layer has a thickness of at least 10 µm.
  21. A steel part according to claim 20, characterized in that the combination layer has a thickness comprised between 10 µm and 25 µm.
  22. A steel part according to any one of claims 18 to 21, characterized in that the impregnation layer comprises at least one paraffin oil composed of a set of alkanes from C16 to C32.
  23. A steel part according to any one of claims 18 to 22, characterized in that the impregnation layer comprises at least one synthetic phenolic additive.
  24. A steel part according to claim 23, characterized in that the synthetic phenolic additive is a compound of formula C15H24O.
  25. A steel part according to any one of claims 18 to 24, characterized in that the impregnation layer further comprises at least one additive chosen from the group constituted by calcium or sodium sulfonate, phosphites, diphenylamines, zinc dithiophosphate, nitrites, phosphoramides.
EP15821125.0A 2014-12-23 2015-12-15 Method for surface treatment of a steel component by nitriding or nitrocarburising, oxidising and then impregnating Active EP3237648B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PL15821125T PL3237648T3 (en) 2014-12-23 2015-12-15 Method for surface treatment of a steel component by nitriding or nitrocarburising, oxidising and then impregnating
SI201531209T SI3237648T1 (en) 2014-12-23 2015-12-15 Method for surface treatment of a steel component by nitriding or nitrocarburising, oxidising and then impregnating

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR1463252A FR3030578B1 (en) 2014-12-23 2014-12-23 PROCESS FOR SUPERFICIAL TREATMENT OF A STEEL PART BY NITRURATION OR NITROCARBURING, OXIDATION THEN IMPREGNATION
PCT/FR2015/053511 WO2016102813A1 (en) 2014-12-23 2015-12-15 Method for surface treatment of a steel component by nitriding or nitrocarburising, oxidising and then impregnating

Publications (2)

Publication Number Publication Date
EP3237648A1 EP3237648A1 (en) 2017-11-01
EP3237648B1 true EP3237648B1 (en) 2020-03-18

Family

ID=52684489

Family Applications (1)

Application Number Title Priority Date Filing Date
EP15821125.0A Active EP3237648B1 (en) 2014-12-23 2015-12-15 Method for surface treatment of a steel component by nitriding or nitrocarburising, oxidising and then impregnating

Country Status (24)

Country Link
US (1) US10774414B2 (en)
EP (1) EP3237648B1 (en)
JP (1) JP6608450B2 (en)
KR (1) KR102455917B1 (en)
CN (1) CN107109617B (en)
AU (1) AU2015370805B2 (en)
BR (1) BR112017011508B1 (en)
CA (1) CA2968630C (en)
DK (1) DK3237648T3 (en)
ES (1) ES2785599T3 (en)
FR (1) FR3030578B1 (en)
HU (1) HUE049293T2 (en)
MX (1) MX2017008334A (en)
MY (1) MY188711A (en)
PH (1) PH12017500936A1 (en)
PL (1) PL3237648T3 (en)
PT (1) PT3237648T (en)
RU (1) RU2696992C2 (en)
SG (1) SG11201704798RA (en)
SI (1) SI3237648T1 (en)
TN (1) TN2017000216A1 (en)
TW (1) TWI683036B (en)
WO (1) WO2016102813A1 (en)
ZA (1) ZA201704730B (en)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108359785B (en) * 2018-03-19 2019-12-17 盐城工学院 Strengthening and toughening treatment method for W6Mo5Cr4V2 high-speed steel broach
CN110423977B (en) * 2019-09-05 2021-06-18 合肥工业大学 Gas nitriding method for aluminum material by taking chemical iron-immersion plating as pretreatment
FR3105262B1 (en) * 2019-12-24 2022-04-15 Hydromecanique & Frottement Process and installation for treating a ferrous metal part
RU2736289C1 (en) * 2020-03-05 2020-11-13 Федеральное государственное бюджетное образовательное учреждение высшего образования "Ростовский государственный университет путей сообщения" (ФГБОУ ВО РГУПС) Method of nitriding parts from alloyed steels
RU2737796C1 (en) * 2020-03-05 2020-12-03 Федеральное государственное бюджетное образовательное учреждение высшего образования "Ростовский государственный университет путей сообщения" (ФГБОУ ВО РГУПС) Compound composition for nitriding parts from alloyed steels
CN111423817A (en) * 2020-05-28 2020-07-17 眉山市三泰铁路车辆配件有限公司 Special gas QPQ coupling agent for cast iron product and preparation method thereof
US11590485B2 (en) 2021-01-13 2023-02-28 Saudi Arabian Oil Company Process for modifying a hydroprocessing catalyst
CN112935737A (en) * 2021-03-25 2021-06-11 上齿集团有限公司 Novel spiral bevel gear dry cutting method
FR3141702A1 (en) * 2022-11-07 2024-05-10 Hydromecanique Et Frottement Impregnation liquid, treatment method with such an impregnation liquid, and treated part obtained

Family Cites Families (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55125267A (en) * 1979-03-22 1980-09-26 Kawasaki Heavy Ind Ltd Surface treating method of improving abrasion resistance and corrosion resistance of iron and steel
JPS57141464A (en) * 1980-12-03 1982-09-01 Lucas Industries Ltd Metal member working method
BR8107846A (en) 1980-12-03 1982-09-08 Lucas Industries Ltd STEEL METAL COMPONENT
DE3277585D1 (en) * 1981-09-05 1987-12-10 Lucas Ind Plc Coated metal substrate and method of coating a metal substrate
ZA827448B (en) * 1981-10-15 1983-08-31 Lucas Ind Plc Corrosion resistant steel components and method of manufacture thereof
JPS5977138A (en) * 1982-10-26 1984-05-02 Aisin Chem Co Ltd Friction material for vehicle
GB8310102D0 (en) 1983-04-14 1983-05-18 Lucas Ind Plc Corrosion resistant steel components
JPH0257735A (en) * 1988-08-19 1990-02-27 Toyoda Gosei Co Ltd Vibration preventing rubber
DE4027011A1 (en) * 1990-08-27 1992-03-05 Degussa METHOD FOR IMPROVING THE CORROSION RESISTANCE OF NITROCARBURATED COMPONENTS MADE OF IRON MATERIALS
FR2672059B1 (en) * 1991-01-30 1995-04-28 Stephanois Rech Mec PROCESS FOR PROVIDING FERROUS METAL PARTS, NITRIDATED THEN OXIDIZED, EXCELLENT CORROSION RESISTANCE WHILE MAINTAINING THE ACQUIRED FRICTION PROPERTIES.
KR100215252B1 (en) * 1991-07-16 1999-08-16 쥐. 엘 뽈띠 Ferrous metal parts with simultaneously improved corrosion resistance and friction properties
FR2679258B1 (en) * 1991-07-16 1993-11-19 Centre Stephanois Recherc Meca PROCESS FOR TREATING FERROUS METAL PARTS TO SIMULTANEOUSLY IMPROVE CORROSION RESISTANCE AND FRICTION PROPERTIES THEREOF.
FR2688517B1 (en) 1992-03-10 1994-06-03 Stephanois Rech PROCESS FOR THE PHOSPHATION OF STEEL PARTS, TO IMPROVE THEIR CORROSION AND WEAR RESISTANCES.
JPH083721A (en) * 1994-06-13 1996-01-09 Kayaba Ind Co Ltd Surface treatment of piston rod
US5714015A (en) * 1996-04-22 1998-02-03 Frantz Manufacturing Ferritic nitrocarburization process for steel balls
JP2001323939A (en) * 2000-05-18 2001-11-22 Nsk Ltd Rolling bearing
FR2812888B1 (en) 2000-08-14 2003-09-05 Stephanois Rech Mec PROCESS FOR THE SURFACE TREATMENT OF MECHANICAL PARTS SUBJECT TO BOTH WEAR AND CORROSION
JP4998654B2 (en) * 2001-01-31 2012-08-15 日立オートモティブシステムズ株式会社 Method of gas soft nitriding treatment of steel members
RU2230824C2 (en) * 2002-04-09 2004-06-20 Общество с ограниченной ответственностью "Борец" Method of chemicothermal treatment of a material on the base of iron alloy, the material on the base of iron alloy and a component of a block of an immersion centrifugal pump
RU2230825C2 (en) * 2002-08-30 2004-06-20 Общество с ограниченной ответственностью "Борец" Method of chemicothermal treatment of a material on the base of powder alloys of iron and a component of a block of an immersion centrifugal pump
FR2972459B1 (en) 2011-03-11 2013-04-12 Hydromecanique & Frottement FOUNDED SALT BATHS FOR NITRIDING STEEL MECHANICAL PARTS, AND METHOD FOR IMPLEMENTING THE SAME

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Also Published As

Publication number Publication date
BR112017011508A2 (en) 2018-02-27
HUE049293T2 (en) 2020-09-28
FR3030578A1 (en) 2016-06-24
WO2016102813A1 (en) 2016-06-30
TWI683036B (en) 2020-01-21
PT3237648T (en) 2020-05-27
PH12017500936B1 (en) 2017-11-20
RU2017126188A3 (en) 2019-06-07
RU2017126188A (en) 2019-01-24
US10774414B2 (en) 2020-09-15
TW201631183A (en) 2016-09-01
JP2018502220A (en) 2018-01-25
KR20170097736A (en) 2017-08-28
SG11201704798RA (en) 2017-07-28
ZA201704730B (en) 2018-05-30
AU2015370805A1 (en) 2017-08-10
PL3237648T3 (en) 2020-08-24
RU2696992C2 (en) 2019-08-08
MX2017008334A (en) 2018-04-24
CA2968630A1 (en) 2016-06-30
FR3030578B1 (en) 2017-02-10
PH12017500936A1 (en) 2017-11-20
EP3237648A1 (en) 2017-11-01
MY188711A (en) 2021-12-24
CN107109617A (en) 2017-08-29
JP6608450B2 (en) 2019-11-20
DK3237648T3 (en) 2020-05-11
ES2785599T3 (en) 2020-10-07
US20170349997A1 (en) 2017-12-07
CA2968630C (en) 2019-08-27
CN107109617B (en) 2020-01-14
BR112017011508B1 (en) 2021-08-10
KR102455917B1 (en) 2022-10-17
SI3237648T1 (en) 2020-09-30
AU2015370805B2 (en) 2020-10-15
TN2017000216A1 (en) 2018-10-19

Similar Documents

Publication Publication Date Title
EP3237648B1 (en) Method for surface treatment of a steel component by nitriding or nitrocarburising, oxidising and then impregnating
FR2731232A1 (en) METHOD OF TREATING FERROUS SURFACES SUBJECTED TO HIGH FRICTIONAL SOLLICITATIONS
EP2683845B1 (en) Salt bath for nitriding of steel workpieces and its related production method
EP0524037B1 (en) Treatment process for iron components to improve simultaneously their corrosion resistance and their friction properties
WO2013117759A1 (en) Method for anodizing parts made of an aluminum alloy
EP0497663B2 (en) Method of manufacturing corrosion resistant steel components and keeping their friction properties by nitriding and then oxidizing them
EP3056583A1 (en) Method for manufacturing a part made of nitrided low-alloy steel
EP1180552B1 (en) Method for surface treatment of mechanical pieces subjected to wear and corrosion
WO2006111661A1 (en) Pair of guiding element of which on is made of a specific steel leading to improved anti-seizing performances
WO2021130460A1 (en) Method for treating a part made of ferrous metal, and part made of ferrous metal
FR3141702A1 (en) Impregnation liquid, treatment method with such an impregnation liquid, and treated part obtained
FR3077303A1 (en) ANODIZATION METHOD AND SYSTEM THEREOF
JP2005163071A (en) Hard carbon film, and method for manufacturing the same
JP2005246468A (en) Covering tool for warm and hot working excellent in lubricant adhesiveness and seizure resistance

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

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

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20170717

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

DAX Request for extension of the european patent (deleted)
RAV Requested validation state of the european patent: fee paid

Extension state: MA

Effective date: 20170721

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: GRANT OF PATENT IS INTENDED

INTG Intention to grant announced

Effective date: 20190329

GRAJ Information related to disapproval of communication of intention to grant by the applicant or resumption of examination proceedings by the epo deleted

Free format text: ORIGINAL CODE: EPIDOSDIGR1

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

INTC Intention to grant announced (deleted)
RIN1 Information on inventor provided before grant (corrected)

Inventor name: MAGDINIER, PIERRE-LOUIS

Inventor name: DESBOUCHE-JANNY, MARIE-NOELLE

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: GRANT OF PATENT IS INTENDED

INTG Intention to grant announced

Effective date: 20191011

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE PATENT HAS BEEN GRANTED

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: DE

Ref legal event code: R096

Ref document number: 602015049103

Country of ref document: DE

REG Reference to a national code

Ref country code: AT

Ref legal event code: REF

Ref document number: 1245991

Country of ref document: AT

Kind code of ref document: T

Effective date: 20200415

Ref country code: IE

Ref legal event code: FG4D

Free format text: LANGUAGE OF EP DOCUMENT: FRENCH

REG Reference to a national code

Ref country code: DK

Ref legal event code: T3

Effective date: 20200506

REG Reference to a national code

Ref country code: FI

Ref legal event code: FGE

REG Reference to a national code

Ref country code: PT

Ref legal event code: SC4A

Ref document number: 3237648

Country of ref document: PT

Date of ref document: 20200527

Kind code of ref document: T

Free format text: AVAILABILITY OF NATIONAL TRANSLATION

Effective date: 20200519

REG Reference to a national code

Ref country code: NL

Ref legal event code: FP

REG Reference to a national code

Ref country code: SE

Ref legal event code: TRGR

REG Reference to a national code

Ref country code: NO

Ref legal event code: T2

Effective date: 20200318

REG Reference to a national code

Ref country code: EE

Ref legal event code: FG4A

Ref document number: E019216

Country of ref document: EE

Effective date: 20200430

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

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: 20200318

REG Reference to a national code

Ref country code: SK

Ref legal event code: T3

Ref document number: E 34260

Country of ref document: SK

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

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: 20200318

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: 20200318

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: 20200619

REG Reference to a national code

Ref country code: LT

Ref legal event code: MG4D

REG Reference to a national code

Ref country code: HU

Ref legal event code: AG4A

Ref document number: E049293

Country of ref document: HU

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2785599

Country of ref document: ES

Kind code of ref document: T3

Effective date: 20201007

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

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: 20200318

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: 20200318

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: 20200718

REG Reference to a national code

Ref country code: AT

Ref legal event code: UEP

Ref document number: 1245991

Country of ref document: AT

Kind code of ref document: T

Effective date: 20200318

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 602015049103

Country of ref document: DE

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: 20201221

REG Reference to a national code

Ref country code: HU

Ref legal event code: HC9C

Owner name: H.E.F., FR

VS25 Lapsed in a validation state [announced via postgrant information from nat. office to epo]

Ref country code: MA

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: 20200318

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: 20200318

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: 20201215

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: 20200318

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: 20200318

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

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: 20200318

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: 20200318

REG Reference to a national code

Ref country code: HU

Ref legal event code: HC9C

Owner name: H.E.F., FR

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

Effective date: 20230515

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

Ref country code: NL

Payment date: 20231122

Year of fee payment: 9

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

Ref country code: SK

Payment date: 20231124

Year of fee payment: 9

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

Ref country code: GB

Payment date: 20231113

Year of fee payment: 9

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

Ref country code: TR

Payment date: 20231130

Year of fee payment: 9

Ref country code: SI

Payment date: 20231121

Year of fee payment: 9

Ref country code: SE

Payment date: 20231123

Year of fee payment: 9

Ref country code: RO

Payment date: 20231127

Year of fee payment: 9

Ref country code: PT

Payment date: 20231117

Year of fee payment: 9

Ref country code: NO

Payment date: 20231128

Year of fee payment: 9

Ref country code: IT

Payment date: 20231122

Year of fee payment: 9

Ref country code: IE

Payment date: 20231122

Year of fee payment: 9

Ref country code: HU

Payment date: 20231130

Year of fee payment: 9

Ref country code: FR

Payment date: 20231227

Year of fee payment: 9

Ref country code: FI

Payment date: 20231120

Year of fee payment: 9

Ref country code: EE

Payment date: 20231122

Year of fee payment: 9

Ref country code: DK

Payment date: 20231129

Year of fee payment: 9

Ref country code: DE

Payment date: 20231122

Year of fee payment: 9

Ref country code: CZ

Payment date: 20231122

Year of fee payment: 9

Ref country code: BG

Payment date: 20231130

Year of fee payment: 9

Ref country code: AT

Payment date: 20231122

Year of fee payment: 9

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

Ref country code: PL

Payment date: 20231201

Year of fee payment: 9

Ref country code: BE

Payment date: 20231121

Year of fee payment: 9

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

Ref country code: ES

Payment date: 20240111

Year of fee payment: 9

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

Ref country code: CH

Payment date: 20240102

Year of fee payment: 9