EP1281786A1 - Anti-corrosion treatment - Google Patents

Anti-corrosion treatment Download PDF

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Publication number
EP1281786A1
EP1281786A1 EP02291943A EP02291943A EP1281786A1 EP 1281786 A1 EP1281786 A1 EP 1281786A1 EP 02291943 A EP02291943 A EP 02291943A EP 02291943 A EP02291943 A EP 02291943A EP 1281786 A1 EP1281786 A1 EP 1281786A1
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EP
European Patent Office
Prior art keywords
steel
surface portion
coating
contact
metal
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.)
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Application number
EP02291943A
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German (de)
French (fr)
Inventor
François P. LeCoester
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.)
Sogefi Suspensions SA
Original Assignee
Allevard Rejna Autosuspensions SA
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Filing date
Publication date
Application filed by Allevard Rejna Autosuspensions SA filed Critical Allevard Rejna Autosuspensions SA
Publication of EP1281786A1 publication Critical patent/EP1281786A1/en
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
    • C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
    • C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
    • C23F13/08—Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
    • C23F13/12—Electrodes characterised by the material
    • C23F13/14—Material for sacrificial anodes
    • 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
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
    • C23C4/131—Wire arc spraying

Definitions

  • the present invention relates to an anti-corrosion treatment method as well as a use of this process to protect an area sensitive of a suspension device for motor vehicles.
  • the material placed at the anode is generally used in the form of a metal insert fixed to the sensitive area of one of the parts by gluing, riveting, crimping ...
  • the object of the present invention is to solve these problems techniques.
  • This object is achieved, according to the invention, by means of a method of treatment of at least a surface portion of a first part of a system consisting of a first part and a second steel part which are intended to be in dynamic contact in a contact zone dynamics formed by at least said surface portion of the first part and a surface portion of the second part, by the fact that performs the prior cleaning of at least said portion of the surface of said first part, an electric arc is created between two metallic wires to produce a liquid metal, said liquid metal is projected at least on said surface portion of said first part so as to produce a anodic coating for cathodic protection of the steel of which said second part, said anodic coating having a potential electrochemical weaker than that of the constituent steel of said second room.
  • the anodic coating has a lower electrochemical potential than that of the constituent steel of said second part regardless of the electrolyte present in the area of contact.
  • electrochemical potential of the anodic coating of the first part is smaller than that of the steel making up the second part.
  • electrical continuity, forming the protection of the system appears in the presence of moisture as soon as direct contact between the two parts of the system takes place.
  • said coating anodic has a lower electrochemical potential than the most small electrochemical potential of the two constituent steels of said first and second parts in dynamic contact.
  • a layer of phosphating and painting at least on said anodic coating of said second piece.
  • any other surface treatment aimed at protecting and covering the anodic coating of said second part can be envisaged, such as for example galvanizing.
  • said layer of paint is applied by cataphoresis.
  • said coating anodic has a roughness (Ra) greater than 25 ⁇ m.
  • said metal is projected liquid by means of a compressed air flow.
  • the two metal wires are made of the same metal or two different metals chosen from the zinc, aluminum or one of their alloys.
  • the prior cleaning of said portion of surface of said first part is made by sandblasting.
  • said first part has at least on the portion of surface intended to be treated by projection of a metal liquid, a surface condition suitable for good attachment of the deposit metallic.
  • the surface is cleaned of all impurities and its surface condition presents an uneven relief conducive to the creation of connections between the deposited metallic coating and the steel of the first room.
  • a layer of phosphating and painting on the first piece at least on the portion of surface which forms with the surface portion of the second part the dynamic contact area.
  • the liquid metal is projected onto the first part before any phosphating, painting, galvanizing and / or assembling the two parts of the system.
  • Another subject of the invention is a use of the defined method above to protect from corrosion at least the end turn of a spring each forming with a lower cup and / or upper one first and second pieces of steel in dynamic contact in a suspension device for vehicle.
  • the cup forms the first part of the system which is coated with metal spray, while the spring forms the second part presenting the protection cathodic induced by said anodic coating.
  • the protective coating is obtained according to the invention by electrothermal projection using a torch supplied with air compressed or neutral gas.
  • the protection of the second part is ensured, in a first time, mechanically by the surface finishing layers (in particular, the phosphate and paint layer), then in a second time, after destruction of these layers following mutual abrasion of two parts in contact, by cathodic protection resulting from coupling galvanic which is established between the second exposed part and the deposit metal of the first part placed in cathode position.
  • the surface finishing layers in particular, the phosphate and paint layer
  • the protective metallic coating has a very roughness pronounced favorable to wedging and non-sliding of the parts in contact, despite the intense friction generated between the two parts.
  • the two parts remain in contact well wedged, despite the high friction existing between the spring and the cup.
  • the high roughness of the metallic coating caused by the type of deposit chosen ensures, when said coating is initially covered with a layer of phosphating and paint, a exposure of the first piece prior to that of the second piece coated with a layer of phosphating and paint only.
  • this protective metallic coating applied under liquid form has, after cooling, a high adhesion to steel, which gives it a stronger hold on the part.
  • FIG. 1 represents an embodiment of the method of the invention applied to the anti-corrosion treatment of a piece P of steel, materialized here by a flat wall.
  • the part has a surface portion S intended to come in dynamic contact with another steel part not shown in a contact area.
  • the surface portion S must therefore be treated to protect the subsequent assembly of the two parts from corrosion.
  • the surface portion S is cleaned beforehand or pickled, and is then placed opposite a torch T intended for the electrothermal projection of a protective metallic coating.
  • the surface portion S is optionally sanded to improve adhesion protective coating.
  • the surface portion S is delimited so as to encompass the surface intended for the contact of the part P with another part.
  • the torch T comprises a housing B in which are fixed two metal wires F 1 , F 2 , brought to an electrical potential and forming electrodes.
  • the wires F 1 , F 2 are displaced longitudinally in sheaths G 1 , G 2 and their respective ends protrude outside the housing B at the center of a deflector D.
  • the two sheaths G 1 , G 2 are maintained in a precise spatial orientation with respect to each other by means of an adjustable spacer E.
  • the optimal inclination ⁇ between the wires F 1 , F 2 is between 25 ° and 35 °.
  • an electric arc is created between the ends of the metal wires F 1 , F 2 to bring their temperature to values between 4000 ° C and 5000 ° C.
  • the metals constituting each of the wires are in the molten state during the entire projection phase.
  • a flow of compressed air A or neutral gas is injected in the space included inside the housing B, between the sheaths G 1 , G 2 and the spacer E, a flow of compressed air A or neutral gas is injected producing a flow of gas entraining the metal droplets liquid at speeds between 100 and 200 m / s. This flow is intended to project the liquid metal at high temperature against the surface portion S to be treated.
  • the wires F 1 , F 2 are consumed and it is necessary to advance them inside the sheaths at predetermined speeds.
  • composition of the filler metal is chosen according to the formula of the steel making up part P and that of the other part intended to come into contact with him.
  • the filler metal which forms the protective coating itself results from the mixture in the liquid state of the metals of the wires F 1 , F 2 .
  • the two wires can be made from the same metal or with two different metals.
  • These metals are chosen from zinc, aluminum or an alloy of these.
  • M coating has a roughness with a value (Ra) greater than 25 ⁇ m, which limits any subsequent untimely movement of the part P relative to the other parts in contact.
  • the steel part P on which the anodic coating has been deposited can further be processed using a range of "multimaterial" phosphating capable of reacting effectively with steel constituting part P, zinc and aluminum from the deposit.
  • This range of phosphating contains, for example to increase its effectiveness, SiF6 fluorides capable of complexing with aluminum, which, when in solution, is poisonous for the phosphating bath.
  • FIGS 2A and 2B show partial sectional views a suspension device for a vehicle.
  • This device includes in particular a lower cup C in steel on which the turn end of a hardened steel spring R comes into bearing contact in a contact zone Z.
  • the cup C is itself assembled, by example by welding, to a shock absorber tube (not shown) to form a strut.
  • FIG. 2A represents the turn of the spring R and the cup lower C treated by the method of the invention in the initial state.
  • the whorl of the spring R consists of a section of hardened steel 1a and a layer of phosphating and paint 2a which initially covers preferably all the steel 1a, in any case at least the portion of Sa surface which corresponds to the surface in contact with the cup lower C.
  • the cup C has a thickness of steel 1b, a coating anodic protector M and a layer of phosphating and paint or of galvanization 2b at least on a portion of surface Sb which corresponds to the surface in contact with the spring R.
  • the spring R like the lower and upper cups, and more particularly the lower cup C are, in service, the seat of abrasion phenomena linked to the respective contacts and friction of the spring R on the cups in a dynamic contact zone Z.
  • the coatings of these parts, whether organic or metallic are fairly quickly damaged and climatic variations initiate corrosion phenomena leading in particular to the appearance of rust red.
  • the contact zone Z evolves during the wear of the different coatings of parts R and C, for each of the parts, it is better to do these, and in particular, metallic deposition, on a respective surface larger than that defining the contact initial (before wear) between the two parts R and C.
  • the coatings, especially the finishing coatings are carried out on the entire part to be treated.
  • the coating M being metallic and therefore a good conductor electric, it is thus established, by contact between the spring R and the cup C, a continuous electrical connection with the steel 1a of the spring R.
  • an electrochemical medium is formed in situ in presence of moisture, debris and / or foreign bodies, favored by the aging and degradation of the layers 2a of the spring R and 2b of the cup C.
  • the contact zone Z between the spring R and the coating M of the cup C then becomes the seat of a coupling phenomenon galvanic.
  • the electrochemical potential of the coating M of the cup C being lower than that of steel 1a of spring R, it is the metal of coating M of the cup C which is attacked as a priority. This attack selective thus preserves the steel 1a of the spring R from corrosion, the steel 1b remaining protected by sufficient covering of the coating M which is partially consumable.
  • Another variant of the process of the invention consists in apply the protective anodic coating on the coil (s) spring terminals.
  • the implementation of the thermal spraying of the coating is performed after a shot peening operation allowing benefit from the good state of cleanliness and responsiveness of the surface finish of the spring.
  • the spring is placed on a presentation in the form of a carousel comprising a sandblasting station and a electric arc projection station.
  • the sandblasting operation can be suppressed if the surface finish induced by shot blasting is sufficient to give a sufficient level of adhesion of the deposit on the spring.
  • the anodic coating protector must be placed only on the terminal coil and not on the intermediate turns. To do this, a mask is placed between the coil terminal to be treated and the remaining part of the spring. The springs are oriented on the presentation machine and the jet of molten metal is directed on the side of the terminal turn by means of a robotic arm.
  • the mask is made of a material resistant to both temperature of the molten metal and the impact of the projection of the metal jet and can integrate an internal cooling circuit.
  • the electric arc projection precedes the finishing operation of surface which must use a range of phosphating "Multimaterial" compatible with the presence of zinc or aluminum on the spring.
  • the spring can be coated by cataphoresis or by powdering.
  • FIGS 3A and 3B show partial sectional views a suspension device for a vehicle.
  • This device includes in particular a lower cup C in steel on which the turn end of a hardened steel spring R comes into bearing contact in a contact zone Z formed by the portions of facing surfaces, Sa and Sb respectively, of the spring R and of the cup C.
  • the cup C is itself assembled, for example by welding, to a tube shock absorber (not shown) to form a strut.
  • FIG. 3A represents the lower cup C and the turn of the spring R treated by the method of the invention in the initial state.
  • the cup C consists of a thickness of steel for stamping 1b and a at least 2b phosphating and painting or galvanizing layer on the surface portion Sb.
  • the coil of the spring R has a section of steel 1a, a anodic protective coating M and a layer of phosphating and paint 2a, at least on the surface portion Sa.
  • the coating M being metallic, it establishes by contact an electrical continuity between the steel 1b of the cup C and the anodic coating M of the spring R.
  • the area contact Z between the cup C and the metal layer M deposited on the spring R is the seat of a phenomenon of galvanic coupling.
  • the electrochemical potential of the coating M of the spring R being lower than that of the steel 1b of the cup C, it is the metal of coating M of the spring R which is attacked as a priority. This attack selective protects steel 1b from cup C from corrosion, steel 1a from spring R being protected by a sufficient covering of coating M.
  • a final variant of the process finally consists in depositing a protective anodic coating on each of the parts to be protected, the galvanic coupling only established when the wear of one of the metal coatings will be complete.
  • a protective anodic coating on each of the parts to be protected, the galvanic coupling only established when the wear of one of the metal coatings will be complete.
  • Each of these coatings anodic can also be covered with a topcoat type phosphating and painting or galvanizing.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Prevention Of Electric Corrosion (AREA)

Abstract

A method for the anti-corrosion treatment of a surface (S), of a first component (P) of a system made up of this first piece and a second steel component which are destined to be in contact in a zone formed by at least a part of the surface of the first component and a part of the surface of the second component, consists of: (a) firstly cleaning the surface on the first component; (b) creating an electric arc between two metal wires (F1, F2) to produce a liquid metal; (c) projecting this liquid metal onto the surface of the first component to produce an anodic coating (M) for the cathodic protection of the steel of the second component. An Independent claim is also included for the utilization of this method for the anti-corrosion protection of at least a part of the surface of a lower and/or upper surface of a dish and/or one or more turns at the end of a spring forming the first and second steel components in dynamic contact in a vehicle suspension device.

Description

La présente invention concerne un procédé de traitement anti-corrosion ainsi qu'une utilisation de ce procédé pour protéger une zone sensible d'un dispositif de suspension pour véhicules automobiles.The present invention relates to an anti-corrosion treatment method as well as a use of this process to protect an area sensitive of a suspension device for motor vehicles.

De manière générale, lorsque deux pièces en acier sont en contact dynamique permanent ou intermittent, leur zone respective de liaison est le siège de phénomènes d'abrasion liés principalement aux frottements mutuels. Lorsque ces pièces présentent un revêtement de surface (peinture organique ou couche de galvanisation), ce dernier est rapidement endommagé et l'exposition aux variations climatiques et en particulier aux intempéries initie la corrosion et accélère ses effets comme l'apparition de rouille.Generally, when two pieces of steel are in permanent or intermittent dynamic contact, their respective area of bond is the seat of abrasion phenomena mainly linked to mutual friction. When these parts have a coating of surface (organic paint or galvanizing layer), the latter is rapidly damaged and exposure to climatic variations and particular to bad weather initiates corrosion and accelerates its effects as the appearance of rust.

Pour combattre ces phénomènes, une solution consiste à interposer entre ces pièces un matériau métallique (zinc, aluminium...) apte à jouer un rôle d'anode consommable à l'égard de l'acier constitutif d'une des deux pièces en contact ou simultanément à l'égard des deux aciers constitutifs desdites deux pièces. Ce mode de protection nécessite l'établissement d'une continuité électrique entre l'acier à protéger et le matériau consommable ainsi que la présence d'un électrolyte. La continuité électrique apparaít dès lors que l'acier et le matériau consommable préalablement revêtus, sont mis à nu et entrent en contact direct suite à la destruction des revêtements de finition, en particulier par abrasion mutuelle des pièces en contact dynamique. Conjointement, un milieu conducteur, constitué de débris et de corps étrangers provenant des phénomènes de projection, forme en présence d'humidité, l'électrolyte nécessaire au fonctionnement de la pile électrochimique.One solution to combat these phenomena is to interpose between these parts a metallic material (zinc, aluminum ...) able to play the role of a consumable anode with respect to the constituent steel of one of the two parts in contact or simultaneously with respect to the two steels constituting said two parts. This protection mode requires establishing electrical continuity between the steel to be protected and the consumable material as well as the presence of an electrolyte. The electrical continuity appears when steel and material consumable previously coated, are exposed and come into contact direct following the destruction of the finish coatings, in particular by mutual abrasion of parts in dynamic contact. Together, a conductive medium, consisting of debris and foreign bodies from projection phenomena, forms in the presence of moisture, the electrolyte necessary for the operation of the electrochemical cell.

Le matériau placé à l'anode est généralement mis en oeuvre sous forme d'un insert métallique fixé sur la zone sensible de l'une des pièces par collage, rivetage, sertissage...The material placed at the anode is generally used in the form of a metal insert fixed to the sensitive area of one of the parts by gluing, riveting, crimping ...

Cependant, compte tenu de l'importance des efforts exercés par les pièces l'une envers l'autre, en particulier dans une jambe de force de suspension, il s'avère que cette fixation n'est pas suffisamment fiable.However, given the importance of the efforts exerted by the pieces towards each other, in particular in a strut suspension, it turns out that this attachment is not sufficiently reliable.

Il en résulte que l'effet de pile escompté ne se produit pas de façon efficace et que la protection cathodique des pièces n'est pas assurée de façon satisfaisante.As a result, the expected stack effect does not occur from effectively and that the cathodic protection of the parts is not satisfactorily ensured.

La présente invention a pour but de résoudre ces problèmes techniques. The object of the present invention is to solve these problems techniques.

Ce but est atteint, selon l'invention, au moyen d'un procédé de traitement d'au moins une portion de surface d'une première pièce d'un système constitué d'une première pièce et d'une seconde pièce en aciers qui sont destinées à être en contact dynamique dans une zone de contact dynamique formée par au moins ladite portion de surface de la première pièce et une portion de surface de la seconde pièce, par le fait qu'on effectue le nettoyage préalable d'au moins ladite portion de surface de ladite première pièce, on crée un arc électrique entre deux fils métalliques pour produire un métal liquide, on projette ledit métal liquide au moins sur ladite portion de surface de ladite première pièce de façon à réaliser un revêtement anodique pour la protection cathodique de l'acier constitutif de ladite seconde pièce, ledit revêtement anodique présentant un potentiel électrochimique plus faible que celui de l'acier constitutif de ladite seconde pièce.This object is achieved, according to the invention, by means of a method of treatment of at least a surface portion of a first part of a system consisting of a first part and a second steel part which are intended to be in dynamic contact in a contact zone dynamics formed by at least said surface portion of the first part and a surface portion of the second part, by the fact that performs the prior cleaning of at least said portion of the surface of said first part, an electric arc is created between two metallic wires to produce a liquid metal, said liquid metal is projected at least on said surface portion of said first part so as to produce a anodic coating for cathodic protection of the steel of which said second part, said anodic coating having a potential electrochemical weaker than that of the constituent steel of said second room.

Avantageusement, le revêtement anodique présente un potentiel électrochimique plus faible que celui de l'acier constitutif de ladite seconde pièce quel que soit l'électrolyte en présence dans la zone de contact.Advantageously, the anodic coating has a lower electrochemical potential than that of the constituent steel of said second part regardless of the electrolyte present in the area of contact.

Ainsi, quel que soit l'électrolyte considéré, c'est-à-dire, quels que soient les débris et les corps étrangers projetés sur le système, le potentiel électrochimique du revêtement anodique de la première pièce est plus petit que celui de l'acier constitutif de la seconde pièce. En conséquence, une continuité électrique, formant la protection du système, apparaít en présence d'humidité dès qu'un contact direct entre les deux pièces du système a lieu.Thus, whatever the electrolyte considered, that is to say, which whatever debris and foreign objects are projected onto the system, electrochemical potential of the anodic coating of the first part is smaller than that of the steel making up the second part. In consequence, electrical continuity, forming the protection of the system, appears in the presence of moisture as soon as direct contact between the two parts of the system takes place.

Selon une caractéristique avantageuse, ledit revêtement anodique présente un potentiel électrochimique plus faible que le plus petit potentiel électrochimique des deux aciers constitutifs desdites première et seconde pièces en contact dynamique.According to an advantageous characteristic, said coating anodic has a lower electrochemical potential than the most small electrochemical potential of the two constituent steels of said first and second parts in dynamic contact.

Selon une autre variante, on applique une couche de phosphatation et de peinture au moins sur ledit revêtement anodique de ladite seconde pièce.According to another variant, a layer of phosphating and painting at least on said anodic coating of said second piece.

En fait, tout autre traitement de surface visant à protéger et recouvrir le revêtement anodique de ladite seconde pièce peut être envisagé, comme par exemple une galvanisation. In fact, any other surface treatment aimed at protecting and covering the anodic coating of said second part can be envisaged, such as for example galvanizing.

De préférence, ladite couche de peinture est appliquée par cataphorèse.Preferably, said layer of paint is applied by cataphoresis.

Selon une caractéristique avantageuse, ledit revêtement anodique présente une rugosité (Ra) supérieure à 25 µm.According to an advantageous characteristic, said coating anodic has a roughness (Ra) greater than 25 µm.

Selon une caractéristique avantageuse, on projette ledit métal liquide au moyen d'un flux d'air comprimé.According to an advantageous characteristic, said metal is projected liquid by means of a compressed air flow.

Selon une autre caractéristique, les deux fils métalliques sont constitués d'un même métal ou de deux métaux différents choisis parmi le zinc, l'aluminium ou un de leurs alliages.According to another characteristic, the two metal wires are made of the same metal or two different metals chosen from the zinc, aluminum or one of their alloys.

De préférence, le nettoyage préalable de ladite portion de surface de ladite première pièce est effectué par sablage.Preferably, the prior cleaning of said portion of surface of said first part is made by sandblasting.

En conséquence, ladite première pièce présente au moins sur la portion de surface destinée à être traitée par projection d'un métal liquide, un état de surface adéquat au bon accrochage du dépôt métallique. En particulier, la surface est nettoyée de toute impureté et son état de surface présente un relief accidenté propice à la création de liaisons entre le revêtement métallique déposé et l'acier de la première pièce.Consequently, said first part has at least on the portion of surface intended to be treated by projection of a metal liquid, a surface condition suitable for good attachment of the deposit metallic. In particular, the surface is cleaned of all impurities and its surface condition presents an uneven relief conducive to the creation of connections between the deposited metallic coating and the steel of the first room.

Selon une autre variante, on applique une couche de phosphatation et de peinture sur la première pièce au moins sur la portion de surface qui forme avec la portion de surface de la seconde pièce la zone de contact dynamique.According to another variant, a layer of phosphating and painting on the first piece at least on the portion of surface which forms with the surface portion of the second part the dynamic contact area.

Selon une autre caractéristique, on projette le métal liquide sur la première pièce avant toute opération de phosphatation, de peinture, de galvanisation et/ou d'assemblage des deux pièces du système.According to another characteristic, the liquid metal is projected onto the first part before any phosphating, painting, galvanizing and / or assembling the two parts of the system.

Un autre objet de l'invention est une utilisation du procédé défini ci-dessus pour protéger de la corrosion au moins la spire d'extrémité d'un ressort formant chacun avec une coupelle inférieure et/ou supérieure l'une des première et seconde pièces d'acier en contact dynamique dans un dispositif de suspension pour véhicule.Another subject of the invention is a use of the defined method above to protect from corrosion at least the end turn of a spring each forming with a lower cup and / or upper one first and second pieces of steel in dynamic contact in a suspension device for vehicle.

De préférence et pour des commodités de réalisation des différents traitements sur chacune des deux pièces, la coupelle forme la première pièce du système qui est revêtue par projection métallique, tandis que le ressort forme la seconde pièce présentant la protection cathodique induite par ledit revêtement anodique. Preferably and for convenience of making different treatments on each of the two parts, the cup forms the first part of the system which is coated with metal spray, while the spring forms the second part presenting the protection cathodic induced by said anodic coating.

Le revêtement protecteur est obtenu selon l'invention par projection électrothermique en utilisant une torche alimentée avec de l'air comprimé ou un gaz neutre.The protective coating is obtained according to the invention by electrothermal projection using a torch supplied with air compressed or neutral gas.

La protection de la seconde pièce est assurée, dans un premier temps, mécaniquement par les couches superficielles de finition (en particulier, la couche de phosphatation et peinture), puis dans un second temps, après destruction de ces couches suite à l'abrasion mutuelle des deux pièces en contact, par protection cathodique résultant du couplage galvanique qui s'établit entre la seconde pièce mise à nu et le dépôt métallique de la première pièce placé en position de cathode.The protection of the second part is ensured, in a first time, mechanically by the surface finishing layers (in particular, the phosphate and paint layer), then in a second time, after destruction of these layers following mutual abrasion of two parts in contact, by cathodic protection resulting from coupling galvanic which is established between the second exposed part and the deposit metal of the first part placed in cathode position.

En fait, dès que l'acier constitutif de la seconde pièce apparaít dans la zone de contact entre les deux pièces, suite à l'attaque des couches de finition, cet acier vient en contact avec le dépôt métallique de la première pièce ; il s'ensuit la naissance d'une continuité électrique entre les deux pièces qui permet de protéger la seconde pièce.In fact, as soon as the steel constituting the second part appears in the contact area between the two rooms, following the attack by finishing layers, this steel comes into contact with the metallic deposit of the first room; it follows the birth of an electrical continuity between the two pieces which protects the second piece.

Le revêtement métallique protecteur présente une rugosité très prononcée favorable au calage et au non-glissement des pièces en contact, malgré le frottement intense engendré entre les deux pièces. En particulier, dans le cas d'un dispositif de suspension type MacPherson, les deux pièces restent en contact bien calé, malgré le frottement important existant entre le ressort et la coupelle. Par ailleurs, la forte rugosité du revêtement métallique entraíné par le type de dépôt choisi (dépôt sous forme de projection de métal liquide), assure, lorsque ledit revêtement est recouvert initialement d'une couche de phosphatation et de peinture, une mise à nu de la première pièce antérieure à celle de la seconde pièce revêtue d'une couche de phosphatation et de peinture uniquement.The protective metallic coating has a very roughness pronounced favorable to wedging and non-sliding of the parts in contact, despite the intense friction generated between the two parts. In particular, in the case of a MacPherson type suspension device, the two parts remain in contact well wedged, despite the high friction existing between the spring and the cup. Furthermore, the high roughness of the metallic coating caused by the type of deposit chosen (deposit under projection of liquid metal), ensures, when said coating is initially covered with a layer of phosphating and paint, a exposure of the first piece prior to that of the second piece coated with a layer of phosphating and paint only.

En outre, ce revêtement métallique protecteur appliqué sous forme liquide possède, après refroidissement, une adhérence élevée à l'acier, ce qui lui assure une tenue renforcée sur la pièce.In addition, this protective metallic coating applied under liquid form has, after cooling, a high adhesion to steel, which gives it a stronger hold on the part.

L'invention sera mieux comprise à la lecture de la description qui va suivre en référence aux dessins annexés, sur lesquels :

  • la figure 1 représente une vue schématique d'un mode de mise en oeuvre du procédé de l'invention ;
  • les figures 2A et 2B représentent des vues schématiques en coupe de pièces traitées par une première variante du procédé de l'invention respectivement avant et après abrasion des couches superficielles de finition.
  • les figures 3A et 3B représentent des vues en coupe de pièces traitées par une seconde variante du procédé de l'invention, respectivement avant et après abrasion des couches superficielles de finition.
The invention will be better understood on reading the description which will follow with reference to the appended drawings, in which:
  • FIG. 1 represents a schematic view of an embodiment of the method of the invention;
  • Figures 2A and 2B show schematic sectional views of parts treated by a first variant of the method of the invention respectively before and after abrasion of the surface finishing layers.
  • Figures 3A and 3B show sectional views of parts treated by a second variant of the method of the invention, respectively before and after abrasion of the surface finishing layers.

La figure 1 représente un mode de mise en oeuvre du procédé de l'invention appliqué au traitement anti-corrosion d'une pièce P en acier, matérialisée ici par une paroi plane.FIG. 1 represents an embodiment of the method of the invention applied to the anti-corrosion treatment of a piece P of steel, materialized here by a flat wall.

La pièce présente une portion de surface S destinée à venir en contact dynamique avec une autre pièce en acier non représentée dans une zone de contact. La portion de surface S doit donc être traitée pour protéger de la corrosion l'assemblage ultérieur des deux pièces.The part has a surface portion S intended to come in dynamic contact with another steel part not shown in a contact area. The surface portion S must therefore be treated to protect the subsequent assembly of the two parts from corrosion.

A cet effet, la portion de surface S est préalablement nettoyée ou décapée, et est ensuite disposée en regard d'une torche T destinée à la projection électrothermique d'un revêtement métallique protecteur. La portion de surface S est éventuellement sablée pour améliorer l'adhérence du revêtement protecteur.To this end, the surface portion S is cleaned beforehand or pickled, and is then placed opposite a torch T intended for the electrothermal projection of a protective metallic coating. The surface portion S is optionally sanded to improve adhesion protective coating.

La portion de surface S est délimitée de façon à englober la surface destinée au contact de la pièce P avec une autre pièce.The surface portion S is delimited so as to encompass the surface intended for the contact of the part P with another part.

La torche T comporte un boítier B dans lequel sont fixés deux fils métalliques F1, F2, portés à un potentiel électrique et formant électrodes. Les fils F1, F2 sont déplacés longitudinalement dans des gaines G1, G2 et leurs extrémités respectives font saillie à l'extérieur du boítier B au centre d'un déflecteur D.The torch T comprises a housing B in which are fixed two metal wires F 1 , F 2 , brought to an electrical potential and forming electrodes. The wires F 1 , F 2 are displaced longitudinally in sheaths G 1 , G 2 and their respective ends protrude outside the housing B at the center of a deflector D.

Les deux gaines G1, G2 sont maintenues dans une orientation spatiale précise l'une par rapport à l'autre au moyen d'une entretoise réglable E. L'inclinaison optimale α entre les fils F1, F2 est comprise entre 25° et 35°.The two sheaths G 1 , G 2 are maintained in a precise spatial orientation with respect to each other by means of an adjustable spacer E. The optimal inclination α between the wires F 1 , F 2 is between 25 ° and 35 °.

Selon l'invention, on crée un arc électrique entre les extrémités des fils métalliques F1, F2 pour porter leur température à des valeurs comprises entre 4000°C et 5000°C. Les métaux constituant chacun des fils sont à l'état de fusion pendant toute la phase de projection.According to the invention, an electric arc is created between the ends of the metal wires F 1 , F 2 to bring their temperature to values between 4000 ° C and 5000 ° C. The metals constituting each of the wires are in the molten state during the entire projection phase.

Dans l'espace compris à l'intérieur du boítier B, entre les gaines G1, G2 et l'entretoise E, est injecté un débit d'air comprimé A ou de gaz neutre produisant un flux de gaz entraínant les gouttelettes de métal liquide à des vitesses comprises entre 100 et 200 m/s. Ce flux est destiné à projeter le métal liquide à haute température contre la portion de surface S à traiter.In the space included inside the housing B, between the sheaths G 1 , G 2 and the spacer E, a flow of compressed air A or neutral gas is injected producing a flow of gas entraining the metal droplets liquid at speeds between 100 and 200 m / s. This flow is intended to project the liquid metal at high temperature against the surface portion S to be treated.

Au fur et à mesure que le métal d'apport M s'accumule sur la zone S, les fils F1, F2 sont consommés et il est nécessaire de les faire avancer à l'intérieur des gaines à des vitesses prédéterminées.As the filler metal M accumulates on the zone S, the wires F 1 , F 2 are consumed and it is necessary to advance them inside the sheaths at predetermined speeds.

La composition du métal d'apport est choisie en fonction de la formule de l'acier constitutif de la pièce P et de celui de l'autre pièce destinée à venir à son contact.The composition of the filler metal is chosen according to the formula of the steel making up part P and that of the other part intended to come into contact with him.

Le métal d'apport qui forme le revêtement protecteur résulte lui-même du mélange à l'état liquide des métaux des fils F1, F2.The filler metal which forms the protective coating itself results from the mixture in the liquid state of the metals of the wires F 1 , F 2 .

Les deux fils peuvent être réalisés avec un même métal ou avec deux métaux différents.The two wires can be made from the same metal or with two different metals.

Ces métaux sont choisis parmi le zinc, l'aluminium ou un alliage de ces derniers.These metals are chosen from zinc, aluminum or an alloy of these.

Le choix des sections relatives et des vitesses d'avance des deux fils permet aussi d'ajuster les proportions des différents éléments métalliques dans le mélange projeté et donc dans le revêtement anodique M.The choice of relative sections and feed rates of two wires also allows you to adjust the proportions of the different elements metallic in the sprayed mixture and therefore in the anodic coating Mr.

Lorsque l'épaisseur du revêtement M atteint la valeur recherchée, la projection de métal est arrêtée et la pièce P est acheminée vers un poste de soudage, et/ou un poste de galvanisation, et/ou un atelier de traitement de surface par phosphatation et peinture avant d'être mise en contact contre une autre pièce par assemblage. Le revêtement M présente une rugosité dont la valeur (Ra) est supérieure à 25 µm, ce qui limite tout déplacement intempestif ultérieur de la pièce P par rapport aux autres pièces en contact.When the thickness of the coating M reaches the value metal projection is stopped and part P is routed to a welding station, and / or a galvanizing station, and / or a surface treatment workshop by phosphating and painting before being brought into contact against another part by assembly. M coating has a roughness with a value (Ra) greater than 25 µm, which limits any subsequent untimely movement of the part P relative to the other parts in contact.

La pièce P en acier sur laquelle le revêtement anodique à été déposé, peut en outre être traitée au moyen d'une gamme de phosphatation « multimatériaux » apte à réagir efficacement avec l'acier constitutif de la pièce P, le zinc et l'aluminium provenant du dépôt. Cette gamme de phosphatation contient, par exemple pour en augmenter son efficacité, des fluorures SiF6 aptes à se complexer avec l'aluminium, qui, lorsqu'il est en solution, est un poison pour le bain de phosphatation.The steel part P on which the anodic coating has been deposited, can further be processed using a range of "multimaterial" phosphating capable of reacting effectively with steel constituting part P, zinc and aluminum from the deposit. This range of phosphating contains, for example to increase its effectiveness, SiF6 fluorides capable of complexing with aluminum, which, when in solution, is poisonous for the phosphating bath.

Les figures 2A et 2B représentent des vues partielles en coupe d'un dispositif de suspension pour véhicule. Ce dispositif comprend notamment une coupelle inférieure C en acier sur laquelle la spire d'extrémité d'un ressort R en acier trempé vient en contact d'appui dans une zone de contact Z. La coupelle C est elle-même assemblée, par exemple par soudure, à un tube d'amortisseur (non représenté) pour former une jambe de force.Figures 2A and 2B show partial sectional views a suspension device for a vehicle. This device includes in particular a lower cup C in steel on which the turn end of a hardened steel spring R comes into bearing contact in a contact zone Z. The cup C is itself assembled, by example by welding, to a shock absorber tube (not shown) to form a strut.

La figure 2A représente la spire du ressort R et la coupelle inférieure C traitée par le procédé de l'invention dans l'état initial. La spire du ressort R est constituée d'une section d'acier trempé 1a et d'une couche de phosphatation et de peinture 2a qui recouvre initialement préférentiellement tout l'acier 1a, en tous les cas au moins la portion de surface Sa qui correspond à la surface au contact avec la coupelle inférieure C.FIG. 2A represents the turn of the spring R and the cup lower C treated by the method of the invention in the initial state. The whorl of the spring R consists of a section of hardened steel 1a and a layer of phosphating and paint 2a which initially covers preferably all the steel 1a, in any case at least the portion of Sa surface which corresponds to the surface in contact with the cup lower C.

La coupelle C possède une épaisseur d'acier 1b, un revêtement protecteur anodique M et une couche de phosphatation et de peinture ou de galvanisation 2b au moins sur une portion de surface Sb qui correspond à la surface au contact avec le ressort R.The cup C has a thickness of steel 1b, a coating anodic protector M and a layer of phosphating and paint or of galvanization 2b at least on a portion of surface Sb which corresponds to the surface in contact with the spring R.

Le ressort R comme les coupelles inférieure et supérieure, et plus particulièrement la coupelle inférieure C sont, en service, le siège de phénomènes d'abrasion liés aux contacts et aux frottements respectifs du ressort R sur les coupelles dans une zone de contact dynamique Z. Les revêtements de ces pièces, qu'ils soient organiques ou métalliques sont assez rapidement endommagés et les variations climatiques initient des phénomènes de corrosion conduisant notamment à l'apparition de rouille rouge.The spring R like the lower and upper cups, and more particularly the lower cup C are, in service, the seat of abrasion phenomena linked to the respective contacts and friction of the spring R on the cups in a dynamic contact zone Z. The coatings of these parts, whether organic or metallic are fairly quickly damaged and climatic variations initiate corrosion phenomena leading in particular to the appearance of rust red.

En conséquence, dans ce mode de réalisation, après usure d'une partie de la couche 2a du ressort R et de la couche 2b de la coupelle C, comme représenté sur la figure 2B, l'acier 1a de la spire se trouve en contact direct avec le revêtement anodique M dans la zone de contact dynamique Z formée par le contact, entre la coupelle C et le ressort R, des deux portions de surfaces Sa et Sb.Consequently, in this embodiment, after wear part of layer 2a of spring R and layer 2b of spring cup C, as shown in FIG. 2B, the steel 1a of the coil is found in direct contact with the anode coating M in the area of dynamic contact Z formed by the contact, between the cup C and the spring R, of the two portions of surfaces Sa and Sb.

La zone de contact Z évoluant au cours de l'usure des différents revêtements des pièces R et C, pour chacune des pièces, il est préférable de faire ces derniers, et en particulier, le dépôt métallique, sur une surface respective plus importante que celle définissant le contact initial (avant usure) entre les deux pièces R et C. Pour s'assurer que la zone de contact est bien revêtue, les revêtements, en particulier les revêtements de finition, sont effectués sur l'ensemble de la pièce à traiter.The contact zone Z evolves during the wear of the different coatings of parts R and C, for each of the parts, it is better to do these, and in particular, metallic deposition, on a respective surface larger than that defining the contact initial (before wear) between the two parts R and C. To ensure that the contact area is well coated, the coatings, especially the finishing coatings are carried out on the entire part to be treated.

Le revêtement M étant métallique et donc bon conducteur électrique, il s'établit ainsi, par contact entre le ressort R et la coupelle C, une liaison électrique continue avec l'acier 1a du ressort R.The coating M being metallic and therefore a good conductor electric, it is thus established, by contact between the spring R and the cup C, a continuous electrical connection with the steel 1a of the spring R.

Par ailleurs, un milieu électrochimique se forme in situ en présence d'humidité, de débris et/ou de corps étrangers, favorisé par le vieillissement et la dégradation des couches 2a du ressort R et 2b de la coupelle C. La zone de contact Z entre le ressort R et le revêtement M de la coupelle C devient alors le siège d'un phénomène de couplage galvanique.Furthermore, an electrochemical medium is formed in situ in presence of moisture, debris and / or foreign bodies, favored by the aging and degradation of the layers 2a of the spring R and 2b of the cup C. The contact zone Z between the spring R and the coating M of the cup C then becomes the seat of a coupling phenomenon galvanic.

Le potentiel électrochimique du revêtement M de la coupelle C étant inférieur à celui de l'acier 1a du ressort R, c'est le métal du revêtement M de la coupelle C qui est attaqué en priorité. Cette attaque sélective préserve ainsi l'acier 1a du ressort R de la corrosion, l'acier 1b restant quant à lui protégé par un recouvrement suffisant du revêtement M qui est partiellement consommable.The electrochemical potential of the coating M of the cup C being lower than that of steel 1a of spring R, it is the metal of coating M of the cup C which is attacked as a priority. This attack selective thus preserves the steel 1a of the spring R from corrosion, the steel 1b remaining protected by sufficient covering of the coating M which is partially consumable.

Une autre variante du procédé de l'invention consiste à appliquer le revêtement anodique protecteur sur la ou les spires terminales du ressort.Another variant of the process of the invention consists in apply the protective anodic coating on the coil (s) spring terminals.

La mise en oeuvre de la projection thermique du revêtement est effectuée après une opération de grenaillage du ressort permettant de bénéficier du bon état de propreté et de réactivité de l'état de surface du ressort.The implementation of the thermal spraying of the coating is performed after a shot peening operation allowing benefit from the good state of cleanliness and responsiveness of the surface finish of the spring.

Une fois grenaillé, le ressort est déposé sur une machine de présentation en forme de carrousel comportant un poste de sablage et un poste de projection à l'arc électrique. L'opération de sablage peut être supprimée si l'état de surface induit par le grenaillage suffit à conférer un niveau d'adhérence suffisant du dépôt sur le ressort.Once shot blasted, the spring is placed on a presentation in the form of a carousel comprising a sandblasting station and a electric arc projection station. The sandblasting operation can be suppressed if the surface finish induced by shot blasting is sufficient to give a sufficient level of adhesion of the deposit on the spring.

Pour des raisons d'esthétique, le revêtement anodique protecteur doit être déposé uniquement sur la spire terminale et non sur les spires intermédiaires. Pour ce faire, un masque est placé entre la spire terminale à traiter et la partie restante du ressort. Les ressorts sont orientés sur la machine de présentation et le jet de métal fondu est dirigé sur le flanc de la spire terminale au moyen d'un bras robotisé. For aesthetic reasons, the anodic coating protector must be placed only on the terminal coil and not on the intermediate turns. To do this, a mask is placed between the coil terminal to be treated and the remaining part of the spring. The springs are oriented on the presentation machine and the jet of molten metal is directed on the side of the terminal turn by means of a robotic arm.

Le masque est fabriqué dans un matériau résistant à la fois à la température du métal fondu et au choc de la projection du jet de métal et peut intégrer un circuit de refroidissement interne.The mask is made of a material resistant to both temperature of the molten metal and the impact of the projection of the metal jet and can integrate an internal cooling circuit.

La projection à l'arc électrique précède l'opération de finition de surface qui doit mettre en oeuvre une gamme de phosphatation « multimatériaux» compatible avec la présence de zinc ou d'aluminium sur le ressort. Le ressort peut être revêtu par cataphorèse ou par poudrage.The electric arc projection precedes the finishing operation of surface which must use a range of phosphating "Multimaterial" compatible with the presence of zinc or aluminum on the spring. The spring can be coated by cataphoresis or by powdering.

Les figures 3A et 3B représentent des vues partieiles en coupe d'un dispositif de suspension pour véhicule. Ce dispositif comprend notamment une coupelle inférieure C en acier sur laquelle la spire d'extrémité d'un ressort R en acier trempé vient en contact d'appui dans une zone de contact Z formée par les portions de surfaces en regard, respectivement Sa et Sb, du ressort R et de la coupelle C. La coupelle C est elle-même assemblée, par exemple par soudure, à un tube d'amortisseur (non représenté) pour former une jambe de force.Figures 3A and 3B show partial sectional views a suspension device for a vehicle. This device includes in particular a lower cup C in steel on which the turn end of a hardened steel spring R comes into bearing contact in a contact zone Z formed by the portions of facing surfaces, Sa and Sb respectively, of the spring R and of the cup C. The cup C is itself assembled, for example by welding, to a tube shock absorber (not shown) to form a strut.

La figure 3A représente la coupelle inférieure C et la spire du ressort R traitée par le procédé de l'invention dans l'état initial. La coupelle C est constituée d'une épaisseur d'acier pour emboutissage 1b et d'une couche de phosphatation et de peinture ou de galvanisation 2b au moins sur la portion de surface Sb.FIG. 3A represents the lower cup C and the turn of the spring R treated by the method of the invention in the initial state. The cup C consists of a thickness of steel for stamping 1b and a at least 2b phosphating and painting or galvanizing layer on the surface portion Sb.

La spire du ressort R possède une section d'acier 1a, un revêtement protecteur anodique M et une couche de phosphatation et de peinture 2a, au moins sur la portion de surface Sa.The coil of the spring R has a section of steel 1a, a anodic protective coating M and a layer of phosphating and paint 2a, at least on the surface portion Sa.

Dans cet autre mode de réalisation, après usure d'une partie de la couche 2a du ressort R et de la couche 2b de la coupelle C, comme représenté sur la figure 3B, l'acier 1b de la coupelle C se trouve en contact direct avec le revêtement anodique M du ressort R dans la zone de contact Z.In this other embodiment, after wear of part of layer 2a of spring R and layer 2b of cup C, as shown in Figure 3B, the steel 1b of the cup C is in contact direct with the anode coating M of the spring R in the area of contact Z.

Comme dans le mode de réalisation précité, le revêtement M étant métallique, il s'établit par contact une continuité électrique entre l'acier 1b de la coupelle C et le revêtement anodique M du ressort R.As in the aforementioned embodiment, the coating M being metallic, it establishes by contact an electrical continuity between the steel 1b of the cup C and the anodic coating M of the spring R.

En présence d'un cataplasme conducteur se formant en présence d'humidité et composé de débris et de corps étrangers, la zone de contact Z entre la coupelle C et la couche métallique M déposée sur le ressort R est le siège d'un phénomène de couplage galvanique. In the presence of a conductive poultice forming in presence of moisture and composed of debris and foreign bodies, the area contact Z between the cup C and the metal layer M deposited on the spring R is the seat of a phenomenon of galvanic coupling.

Le potentiel électrochimique du revêtement M du ressort R étant inférieur à celui de l'acier 1b de la coupelle C, c'est le métal du revêtement M du ressort R qui est attaqué en priorité. Cette attaque sélective préserve l'acier 1b de la coupelle C de la corrosion, l'acier 1a du ressort R étant protégé par un recouvrement suffisant de revêtement M.The electrochemical potential of the coating M of the spring R being lower than that of the steel 1b of the cup C, it is the metal of coating M of the spring R which is attacked as a priority. This attack selective protects steel 1b from cup C from corrosion, steel 1a from spring R being protected by a sufficient covering of coating M.

Une dernière variante du procédé consiste enfin à déposer un revêtement anodique protecteur sur chacune des pièces à protéger, le couplage galvanique ne s'établissant que lorsque l'usure d'un des revêtements métalliques sera complète. Chacun de ces revêtements anodiques peut en outre être recouvert par une couche de finition de type phosphatation et peinture ou galvanisation.A final variant of the process finally consists in depositing a protective anodic coating on each of the parts to be protected, the galvanic coupling only established when the wear of one of the metal coatings will be complete. Each of these coatings anodic can also be covered with a topcoat type phosphating and painting or galvanizing.

Claims (13)

Procédé de traitement anti-corrosion d'au moins une portion de surface (S ; Sa ; Sb) d'une première pièce (P ; R ; C) d'un système constitué d'une première pièce (P ; R ; C) et d'une seconde pièce (P ; C ; R) en aciers (1a, 1b) qui sont destinées à être en contact dans une zone de contact (Z) formée par au moins ladite portion de surface (S ; Sa ; Sb) de la première pièce (P ; R ; C) et une portion de surface (Sb ; Sa) de ladite seconde pièce (P ; C ; R),
   caractérisé en ce qu'on effectue le nettoyage préalable d'au moins ladite portion de surface (S ; Sa ; Sb) qui se trouve sur la première pièce (P ; R ; C), on crée un arc électrique entre deux fils métalliques (F1, F2) pour produire un métal liquide, on projette ledit métal liquide au moins sur ladite portion de surface (S ; Sa ; Sb) de la première pièce (P ; R ; C) de façon à réaliser un revêtement anodique (M) pour la protection cathodique de l'acier (1a ; 1b) constitutif de la seconde pièce (P ; C ; R), ledit revêtement anodique présentant un potentiel électrochimique plus faible que celui de l'acier (1b; 1a) constitutif de ladite seconde pièce (P ; C ; R).Method for anti-corrosion treatment of at least a surface portion (S; Sa; Sb) of a first part (P; R; C) of a system consisting of a first part (P; R; C) and a second piece (P; C; R) of steels (1a, 1b) which are intended to be in contact in a contact zone (Z) formed by at least said surface portion (S; Sa; Sb) of the first part (P; R; C) and a surface portion (Sb; Sa) of said second part (P; C; R),
characterized in that the prior cleaning of at least said surface portion (S; Sa; Sb) which is on the first part (P; R; C) is carried out, an electric arc is created between two metal wires ( F 1 , F 2 ) to produce a liquid metal, said liquid metal is projected at least on said surface portion (S; Sa; Sb) of the first part (P; R; C) so as to produce an anodic coating ( M) for cathodic protection of the steel (1a; 1b) constituting the second part (P; C; R), said anodic coating having a lower electrochemical potential than that of the steel (1b; 1a) constituting said second part (P; C; R). Procédé selon la revendication précédente, caractérisé en ce que ledit revêtement anodique présente un potentiel électrochimique plus faible que celui de l'acier (16 ; 1a) constitutif de ladite seconde pièce (P ; C ; R) quel que soit l'électrolyte en présence dans la zone de contact (Z).Method according to the preceding claim, characterized in that said anodic coating has a lower electrochemical potential than that of the steel (16; 1a) constituting said second part (P; C; R) whatever the electrolyte present in the contact area (Z). Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que ledit revêtement anodique présente un potentiel électrochimique plus faible que le plus petit potentiel électrochimique des deux aciers (1a ; 1b) constitutifs desdites première et seconde pièces (P ; R ; C) en contact.Method according to any one of the preceding claims, characterized in that said anode coating has a lower electrochemical potential than the smallest electrochemical potential of the two steels (1a; 1b) constituting said first and second parts (P; R; C) in touch. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce qu'on applique une couche de phosphatation et de peinture (2a ; 2b) au moins sur ledit revêtement anodique (M) de ladite seconde pièce (P ; C ; R).Method according to any one of the preceding claims, characterized in that a layer of phosphating and paint (2a; 2b) is applied at least to said anodic coating (M) of said second part (P; C; R). Procédé selon la revendication précédente, caractérisé en ce que ladite couche de phosphatation est obtenue par une gamme de phosphatation « multimatériaux » compatible avec le métal dudit revêtement anodique (M) déposé sur ladite première pièce (P ; R ; C).Method according to the preceding claim, characterized in that said phosphating layer is obtained by a range of "multimaterial" phosphating compatible with the metal of said anode coating (M) deposited on said first part (P; R; C). Procédé selon la revendication précédente, caractérisé en ce que ladite gamme de phosphatation « multimatériaux » comporte des fluorures.Method according to the preceding claim, characterized in that the said range of "multimaterial" phosphates comprises fluorides. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que ledit revêtement anodique (M) présente une rugosité (Ra) supérieure à 25 µm.Method according to any one of the preceding claims, characterized in that the said anodic coating (M) has a roughness (Ra) greater than 25 µm. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que ladite couche de peinture (2a, 2b) est appliquée par cataphorèse.Method according to any one of the preceding claims, characterized in that the said layer of paint (2a, 2b) is applied by cataphoresis. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce qu'on projette ledit métal liquide au moyen d'un flux d'air comprimé (A).Method according to any one of the preceding claims, characterized in that the said liquid metal is projected by means of a flow of compressed air (A). Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que les deux fils métalliques (F1, F2) sont constitués d'un même métal ou de deux métaux différents choisis parmi le zinc, l'aluminium ou un de leurs alliages.Method according to any one of the preceding claims, characterized in that the two metal wires (F 1 , F 2 ) consist of the same metal or of two different metals chosen from zinc, aluminum or one of their alloys . Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que ledit nettoyage préalable de ladite portion de surface (S) de ladite première pièce (P ; R ; C) est effectué par sablage.Method according to any one of the preceding claims, characterized in that said preliminary cleaning of said surface portion (S) of said first part (P; R; C) is carried out by sandblasting. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce qu'on projette le métal liquide sur la ladite portion de surface (S ; Sa ; Sb) avant toute opération de phosphatation de peinture, et/ou de galvanisation et/ou d'assemblage des pièces (P ; R ; C).Method according to any one of the preceding claims, characterized in that the liquid metal is projected onto the said surface portion (S; Sa; Sb) before any paint phosphating, and / or galvanizing and / or d '' assembly of parts (P; R; C). Utilisation du procédé selon l'une quelconque des revendications précédentes pour protéger de la corrosion au moins une portion de surface (Sb) d'une coupelle (C) inférieure et/ou supérieure, et/ou la ou les spire(s) d'extrémité d'un ressort (R) formant respectivement les première et seconde pièces d'acier en contact dynamique dans un dispositif de suspension de véhicule.Use of the method according to any one of previous claims to protect against corrosion at least one surface portion (Sb) of a lower and / or upper cup (C), and / or the end turn (s) of a spring (R) respectively forming the first and second pieces of steel in dynamic contact in a vehicle suspension device.
EP02291943A 2001-08-02 2002-08-01 Anti-corrosion treatment Withdrawn EP1281786A1 (en)

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FR0110402A FR2828213B1 (en) 2001-08-02 2001-08-02 ANTI-CORROSION TREATMENT PROCESS
FR0110402 2001-08-02

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US7341533B2 (en) * 2003-10-24 2008-03-11 General Motors Corporation CVT housing having wear-resistant bore

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JPS6075367A (en) * 1983-09-30 1985-04-27 Nippon Steel Corp Production of automobile
JPS60138080A (en) * 1983-12-26 1985-07-22 Toyota Motor Corp Rust preventive treatment of spring steel
EP0445353A1 (en) * 1990-01-30 1991-09-11 Air Products And Chemicals, Inc. Electric arc spraying of reactive metals
JPH0633293A (en) * 1992-07-14 1994-02-08 Nippon Steel Corp Manufacture of corrosion resistant spring for hanging
EP0872577A1 (en) * 1997-04-14 1998-10-21 Allevard Process for the cathodic protection of a suspension device
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JPS6075367A (en) * 1983-09-30 1985-04-27 Nippon Steel Corp Production of automobile
JPS60138080A (en) * 1983-12-26 1985-07-22 Toyota Motor Corp Rust preventive treatment of spring steel
EP0445353A1 (en) * 1990-01-30 1991-09-11 Air Products And Chemicals, Inc. Electric arc spraying of reactive metals
JPH0633293A (en) * 1992-07-14 1994-02-08 Nippon Steel Corp Manufacture of corrosion resistant spring for hanging
EP0872577A1 (en) * 1997-04-14 1998-10-21 Allevard Process for the cathodic protection of a suspension device
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7341533B2 (en) * 2003-10-24 2008-03-11 General Motors Corporation CVT housing having wear-resistant bore

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FR2828213B1 (en) 2004-04-02

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