EP0037143A1 - Hot dip coating process - Google Patents

Hot dip coating process Download PDF

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Publication number
EP0037143A1
EP0037143A1 EP81200313A EP81200313A EP0037143A1 EP 0037143 A1 EP0037143 A1 EP 0037143A1 EP 81200313 A EP81200313 A EP 81200313A EP 81200313 A EP81200313 A EP 81200313A EP 0037143 A1 EP0037143 A1 EP 0037143A1
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EP
European Patent Office
Prior art keywords
zinc
bath
metal
aluminum
layer
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Granted
Application number
EP81200313A
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German (de)
French (fr)
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EP0037143B1 (en
Inventor
Jacques Pelerin
Dimitri Coutsouradis
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Centre de Recherches Metallurgiques CRM ASBL
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Centre de Recherches Metallurgiques CRM ASBL
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Priority claimed from BE6/47114A external-priority patent/BE882430A/en
Priority claimed from BE6/47184A external-priority patent/BE883725A/en
Priority claimed from BE6/47183A external-priority patent/BE883724A/en
Application filed by Centre de Recherches Metallurgiques CRM ASBL filed Critical Centre de Recherches Metallurgiques CRM ASBL
Publication of EP0037143A1 publication Critical patent/EP0037143A1/en
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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
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • 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
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/06—Zinc or cadmium or alloys based thereon
    • 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
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/12—Aluminium or alloys based thereon

Definitions

  • the present invention relates to a method of hot coating a material of any shape, but preferably in the form of tube or steel sheets.
  • the process which is the subject of the present description is applicable in all cases where a molten metal bath is used to form a coating on a product as defined above, and this, as well within the framework of the coating. . hot to order, only during continuous processes.
  • the installations constructed for the implementation of these solutions generally comprise a tank separated into two parts by a transverse partition, provided in its lower part, with means to allow the passage from one side to the other of the partition, of the material. treat. It is thus normal to find at the bottom of the tank, over its entire base section, a lead bath of height greater than the passage means arranged in the partition, and on either side of this same partition, supernatant on the lead bath, a bath of almost pure zinc and a bath of Zn alloys about 10% Al.
  • the sheet to be treated penetrates on one side of the transverse partition, passes successively into the bath of unalloyed zinc which floats on lead and then in the lead bath and, after passing to the other side of the partition, exits through the bath of Zn-Al alloy, which gives the desired coating layer.
  • This method is mainly applied in the case of Zn - 10% Al alloys, that is to say coating baths for which the temperatures of use are close to those of traditional galvanizing baths, because the melting temperatures materials constituting the two baths on either side of the partition are almost identical.
  • the use of this type of process in the case of Zn alloys with a high Al content, in particular in the case of alloys having a melting point higher than that of traditional galvanizing baths, located around 440 - 460 ° C, is impossible
  • the process which is the subject of the present invention makes it possible to avoid the aforementioned defect, and this, by acting at the level of the heating means of the tank containing the coating bath of the treated product.
  • the hot coating process is essentially characterized in that the product to be treated is immersed in at least two metal baths whose temperatures are different.
  • a first variant of the process of the invention consists in using, as metal baths, baths of molten metal. It should be understood that all of the metals mentioned below are understood to be accompanied by the usual impurities inherent and inevitable in their methods of preparation.
  • a second variant in carrying out the process of the invention consists in using, as metal baths on the one hand, a bath composed of an almost pure or weakly alloyed metal, then in a later stage, a bath composed of an alloy of the aforementioned metal, with one or more other metals.
  • a third alternative embodiment of the process of the invention consists in using a lead bath, followed in a later stage, by a zinc alloy bath with one or more metals.
  • a fourth embodiment of the process to which the invention relates consists in using a metal bath of Zn, followed in a later stage, by a bath of zinc alloy with one or more metals (for example Zn + Al ), soaking in a lead bath which can however be inserted directly after the first bath.
  • a metal bath of Zn followed in a later stage, by a bath of zinc alloy with one or more metals (for example Zn + Al ), soaking in a lead bath which can however be inserted directly after the first bath.
  • This fourth variant proves to be particularly advantageous in the case where we are dealing with semi-quenched steels, quenched or weakly alloyed with silicon. It had in fact been found that in the case of these steels, the conventional galvanization process led to the appearance of excess thicknesses on the metal, a matt gray appearance of the deposit, poor adhesion and inequalities in the formation of the substrates. intermetallic layers, which could lead to the disposal of galvanized parts.
  • the product to be treated which may be hot, is immersed in a first bath of molten zinc for a time t, then subsequently in another molten bath composed of zinc alloys, for a duration t 'advantageously not less than t.
  • the first bath can be zinc or zinc-aluminum
  • the second can also be molten zinc-aluminum (an intermediate dip in molten lead can also be considered).
  • the duration of the passage of the steel in the first bath is advantageously less than 3 minutes, while that of the passage in the second bath is advantageously less than 20 minutes.
  • the multilayer coating produced has a multi-phase metallic outer layer composed of phases enriched in at least two different metals, the number of phases enriched in a given metal being advantageously greater than one.
  • intermetallic layers containing in particular iron or be made of a specific metal (hereinafter called M 1 ), while the polyphase surface layer comprises metal M 1 , thus that one or more other metals (hereinafter called M 2 ... M n ) forming with M 1 and / or between them the different phases mentioned above.
  • the immersion relating to the intermetallic layer or layers may lead to deposition of the said layer by electrolytic means.
  • bringing the substrate into contact with the metal layer M 1 and / or bringing the outer polyphase layer into contact with the immediately underlying layer is effected by deposit in molten form. of the metal M 1 or of the polyphase layer, the melting of the deposited material preferably being carried out immediately at the time of deposition, under a neutral and preferably inert atmosphere (Ar), for example by means of a plasma torch.
  • a neutral and preferably inert atmosphere Ar

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Coating With Molten Metal (AREA)

Abstract

1. Hot dip coating process for products of any shape made of killed, semi-killed or silicon steel in which the said products are dipped into an initial bath made up basically of zinc or a first zinc-aluminium alloy and then into a second bath comprising basically a second zinc-aluminium alloy, the aforementioned first and second baths being at different temperatures, and which is characterized by the fact that at least one of the baths of zinc-aluminium alloy has an aluminium content of between 3 % and 10 % and at least one of the elements Sb, Ce, Mg, La and Sn is added to it in an amount not exceeding 0.5 % by weight.

Description

La présente invention a trait à un procédé de revêtement à chaud d'un matériau de forme quelconque, mais se présentant de préférence sous forme de tube ou de tôles en acier.The present invention relates to a method of hot coating a material of any shape, but preferably in the form of tube or steel sheets.

Le procédé, objet de la présente description, est d'application dans tous les cas où l'on emploie un bain métallique fondu pour former un revêtement sur un produit tel que défini plus haut, et ce, aussi bien dans le cadre du revête- . ment à chaud à façon, qu'au cours de processus continus.The process which is the subject of the present description is applicable in all cases where a molten metal bath is used to form a coating on a product as defined above, and this, as well within the framework of the coating. . hot to order, only during continuous processes.

Toutefois, dans le but de montrer plus clairement l'intérêt de l'invention dont il est question, notre description sera axée sur le revêtement par trempé de tôles ou de tubes d' acier dans des bains de zinc et d'alliages Zn-Al, et cela uniquement à titre d'exemple et sans que cela soit restrictif à ce type d'application.,However, in order to show more clearly the advantage of the invention in question, our description will focus on the dip coating of steel sheets or tubes in baths of zinc and Zn-Al alloys , and this only by way of example and without this being restrictive to this type of application.,

Les processus usuels de revêtement par trempé tels que la galvanisation au trempé d'un laminé, par exemple une tôle ou un tube en acier, se déroulent ordinairement en deux phases, à savoir :

  • - une phase,dite de préparation, qui consiste à débarraser la surface de la tôle ou du tube de tout ce qui pourrait nuire à l'obtention d'un produit galvanisé satisfaisant, par exemple graisse, cambouis, poussières, etc..., ce qui se fait généralement par une opération de dégraissage suivie d'un rinçage, d'un décapage, d'un nouveau rinçage et d'un fluxage (sec ou humide). Dans la majorité des processus continus, dans le cas des tôles, cette opération est réalisée en faisant passer le produit considéré dans une enceinte où règne une atmosphère gazeuse, essentiellement réductrice.
  • - une phase qui consiste à tremper le matériau ainsi préparé dans un bain de zinc liquide à une température le plus souvent comprise entre 440°C et 460°C, pendant une durée appropriée.
The usual dip coating processes such as dip galvanizing of a laminate, for example a steel sheet or tube, usually take place in two phases, namely:
  • - a so-called preparation phase, which consists in ridding the surface of the sheet or tube of anything that could be detrimental to obtaining a satisfactory galvanized product, for example grease, sludge, dust, etc., which is generally done by a degreasing operation followed by rinsing, pickling, rinsing again and fluxing (dry or wet). In the majority of continuous processes, in the case of sheets, this operation is carried out by passing the product under consideration into an enclosure in which there is a gaseous, essentially reducing, atmosphere.
  • - A phase which consists in dipping the material thus prepared in a bath of liquid zinc at a temperature usually between 440 ° C and 460 ° C, for an appropriate period.

Les opérations dont il est question ci-dessus ayant trait au dégraissage, décapage et fluxage, ont' été surtout élaborées pour des installations de revêtement à chaud au trempé dans lesquelles le bain métallique liquide est composé de zinc pratiquement pur, à l'exception des impuretés habituelles.The operations referred to above relating to the degreasing, pickling and fluxing have 'been especially developed for coating systems Hot dip in which the liquid metal bath is composed of almost pure zinc, with the exception of usual impurities.

Ces dernières années, on a assisté au développement de revête- mentsau trempé, composés d'alliages Zn-Al et autres ..., qui ont connu un succès certain dû au fait qu'ils présentent un certain nombres d'avantages non négligeables au point de vue de la résistance à la corrosion, par rapport au revêtement au trempé dans le zinc ou d'autres métaux non alliés.In recent years, we have witnessed the development of hardened coatings, composed of Zn-Al alloys and others ..., which have known a certain success due to the fact that they have a certain number of significant advantages in from the point of view of corrosion resistance, compared to coating by dipping in zinc or other unalloyed metals.

Dans le cas d'une préparation de surface utilisée dans la galvanisation à façon conventionnelle, ou la galvanisation de tubes ou de tôles dans des bains de galvanisation traditionnels et caractérisée par un dégraissage, un décapage et un fluxage, des problèmes majeurs apparaissent au niveau de défauts (manques,...) dans le revêtement de galvanisation, et ce de par la présence d'additifs au bain de revêtement, tels que l'A1, ... Ceux-ci sont dus principalement à une réaction entre les agents fluxants et les éléments d'addition au bain métallique de revêtement et en particulier l'Al.In the case of a surface preparation used in conventional galvanizing, or the galvanizing of tubes or sheets in traditional galvanizing baths and characterized by degreasing, pickling and fluxing, major problems appear at the level of defects (gaps, ...) in the galvanizing coating, and this by the presence of additives to the coating bath, such as A1, ... These are mainly due to a reaction between the fluxing agents and the additives to the metallic coating bath and in particular Al.

La mise en oeuvre de revêtements à base d'alliages de Zn, Al et autres a nécessité la conception de nouvelles lignes de traitements sous atmosphères fort élaborées ou du moins, la transformation coûteuse de lignes existantes, de manière à obtenir une préparation de surface adaptée aux nouveaux alliages de revêtement mis en oeuvre. Ces nouveaux bains métalliques d'alliages nécessitent une préparation de surface plus poussée que dans le cas d'une galvanisation classique et notamment en imposant une contrainte plus sévère, par exemple dans le cas de points de rosée plus bas.The use of coatings based on Zn, Al and other alloys necessitated the design of new lines of treatment in very sophisticated atmospheres or at least the costly transformation of existing lines, so as to obtain a suitable surface preparation. to the new coating alloys used. These new metal alloy baths require more extensive surface preparation than in the case of conventional galvanization and in particular by imposing a more severe stress, for example in the case of lower dew points.

Un type de solution préconisé par plusieurs sociétés dont la NIPPON KOKAN K.K., et ce dans le cadre du revêtement Zn-Al consiste à faire passer la tôle fluxée dans un premier bain de Zn,puis dans un bain de plomb, puis seulement dans un bain liquide de Zn-Al, de manière à former un revêtement en , alliagesde Zn-Al désiré.One type of solution recommended by several companies including NIPPON KOKAN KK, and this within the framework of the Zn-Al coating consists in passing the fluxed sheet in a first bath of Zn, then in a lead bath, then only in a bath Zn-Al liquid, so as to form a coating of the desired Zn-Al alloys.

Les installations construites pour la mise en oeuvre de ces solutions comprennent généralement une cuve séparée en deux parties par une cloison transversale, pourvue dans sa partie inférieure, de moyens pour permettre le passage d'un côté à l'autre de la cloison, du matériau à traiter. C'est ainsi qu' il est normal de trouver au fond de la cuve, sur toute sa section de base, un bain de plomb de hauteur supérieure aux moyens de passage aménagés dans la cloison, et de part et d'autre de cette même cloison, surnageant sur le bain de plomb, un bain de zinc presque pur et un bain d'alliages Zn environ 10 % Al. La tôle à traiter pénètre d'un côté de la cloison transversale, passe successivement dans le bain de zinc non allié qui flotte sur le plomb puis dans le bain de plomb et, après passage de l'autre côté de la cloison, ressort à travers le bain d'alliage Zn-Al, qui donne la couche de revêtement désirée.The installations constructed for the implementation of these solutions generally comprise a tank separated into two parts by a transverse partition, provided in its lower part, with means to allow the passage from one side to the other of the partition, of the material. treat. It is thus normal to find at the bottom of the tank, over its entire base section, a lead bath of height greater than the passage means arranged in the partition, and on either side of this same partition, supernatant on the lead bath, a bath of almost pure zinc and a bath of Zn alloys about 10% Al. The sheet to be treated penetrates on one side of the transverse partition, passes successively into the bath of unalloyed zinc which floats on lead and then in the lead bath and, after passing to the other side of the partition, exits through the bath of Zn-Al alloy, which gives the desired coating layer.

Cette méthode est essentiellement appliquée dans le cas d' alliages Zn - 10 % Al, c'est-à-dire de bains de revêtement pour lesquels les températures d'utilisation sont proches de celles de bains de galvanisation traditionnels, car les températures de fusion des matériaux constituant les deux bains de part et d'autre de la cloison sont presque identiques. Toutefois, l'utilisation de ce type de procédé, dans le cas d'alliages de Zn à hauteur teneur en Al, notamment dans le cas d'alliages ayant un point de fusion supérieur à celui des bains de galvanisation traditionnels, situés aux alentours de 440 - 460°C, est impossibleThis method is mainly applied in the case of Zn - 10% Al alloys, that is to say coating baths for which the temperatures of use are close to those of traditional galvanizing baths, because the melting temperatures materials constituting the two baths on either side of the partition are almost identical. However, the use of this type of process, in the case of Zn alloys with a high Al content, in particular in the case of alloys having a melting point higher than that of traditional galvanizing baths, located around 440 - 460 ° C, is impossible

Le procédé, objet de la présente invention, permet d'éviter le défaut susmentionné, et ce, en agissant au niveau des moyens de chauffage de la cuve contenant le bain de revêtement du produit traité.The process which is the subject of the present invention makes it possible to avoid the aforementioned defect, and this, by acting at the level of the heating means of the tank containing the coating bath of the treated product.

Le procédé de revêtement à chaud, objet de la présente invention, est essentiellement caractérisé en ce que le produit à traiter est immergé dans au moins deux bains métalliques dont les températures sont différentes.The hot coating process, object of the present invention, is essentially characterized in that the product to be treated is immersed in at least two metal baths whose temperatures are different.

Une première variante du procédé de l'invention consiste à utiliser en tant que bains métalliques, des bains de métal fondu. Il doit être entendu que tous les métaux cités ci-après sont compris comme accompagnés des impuretés usuelles inhérentes et inévitables à leurs modes de préparation.A first variant of the process of the invention consists in using, as metal baths, baths of molten metal. It should be understood that all of the metals mentioned below are understood to be accompanied by the usual impurities inherent and inevitable in their methods of preparation.

Une deuxième variante dans La réalisation du procédé de l' invention, consiste à utiliser en tant que bains métalliques d'une part, un bain composé d'un métal presque pur ou faiblement allié, puis dans un stade ultérieur, un bain composé d'un alliage du métal précité, avec un ou plusieurs autres métaux.A second variant in carrying out the process of the invention consists in using, as metal baths on the one hand, a bath composed of an almost pure or weakly alloyed metal, then in a later stage, a bath composed of an alloy of the aforementioned metal, with one or more other metals.

Une troisième variante de réalisation du procédé de l'invention consiste à utiliser un bain de plomb, suivi dans un stade ultérieur, par un bain d'alliage de zinc avec un ou plusieurs métaux.A third alternative embodiment of the process of the invention consists in using a lead bath, followed in a later stage, by a zinc alloy bath with one or more metals.

Un quatrième mode de mise en oeuvre du procédé sur lequel porte l'invention, consiste à utiliser un bain métallique de Zn, suivi dans un stade ultérieur, par un bain d'alliage de zinc avec un ou plusieurs métaux (par exemple Zn + Al),un trempage dans un bain de plomb pouvant toutefois être intercalé directement après le premier bain.A fourth embodiment of the process to which the invention relates, consists in using a metal bath of Zn, followed in a later stage, by a bath of zinc alloy with one or more metals (for example Zn + Al ), soaking in a lead bath which can however be inserted directly after the first bath.

Cette quatrième variante s'avère particulièrement intéressante dans le cas où l'on a affaire à des aciers semi-calmés, calmés ou faiblement alliés au silicium. On avait en effet constaté que dans le cas de ces aciers, le procédé classique de galvanisation conduisait à l'apparition de sur- épaisseurs sur le métal, un aspect gris mat du dépôt, une faible adhérence et des inégalités dans la formation des sous-couches intermétalliques, ce qui pouvait conduire à la mise au rebut des pièces galvanisées.This fourth variant proves to be particularly advantageous in the case where we are dealing with semi-quenched steels, quenched or weakly alloyed with silicon. It had in fact been found that in the case of these steels, the conventional galvanization process led to the appearance of excess thicknesses on the metal, a matt gray appearance of the deposit, poor adhesion and inequalities in the formation of the substrates. intermetallic layers, which could lead to the disposal of galvanized parts.

Dans le cadre de cette quatrième variante, le produit à traiter, lequel peut être chaud, est immergé dans un premier bain de zinc en fusion pendant un temps t, puis ultérieurement dans un autre bain de fusion composé d'alliages de zinc, pendant une durée t' avantageusement non inférieure à t.In the context of this fourth variant, the product to be treated, which may be hot, is immersed in a first bath of molten zinc for a time t, then subsequently in another molten bath composed of zinc alloys, for a duration t 'advantageously not less than t.

Le premier bain peut être du zinc ou du zinc-aluminium, le second peut être également du zinc-aluminium en fusion (un trempage intercalaire dans du plomb fondu peut également être envisagé). La durée du passage de l'acier dans le premier bain est avantageusement inférieure à 3 minutes, tandis que celle du passage dans le second bain est avantageusement inférieure à 20 minutes.The first bath can be zinc or zinc-aluminum, the second can also be molten zinc-aluminum (an intermediate dip in molten lead can also be considered). The duration of the passage of the steel in the first bath is advantageously less than 3 minutes, while that of the passage in the second bath is advantageously less than 20 minutes.

Toujours pour ces aciers semi-calmés, calmés ou alliés au silicium, différentes compositions pour les bains métalliques sont à considérer comme intéressantes parmi lesquelles on peut citer pour le zinc :

Figure imgb0001
Still for these semi-calm steels, calm or alloyed with silicon, different compositions for metallic baths are to be considered as interesting among which we can cite for zinc:
Figure imgb0001

Suivant encore une série d'autres variantes intéressantes du procédé de l'invention, on peut également apporter une autre solution aux problèmes posés par le revêtement métalliques d'aciers spéciaux, par exemple les aciers au Si et surtout il permet de minimiser l'influence de la qualité de la préparation de la surface à traiter tout en permettant d'obtenir des revêtements d'épaisseur constante et d'adhérence satisfaisante, par opposition au revêtement en une couche à base d'alliagesde Zn-Al qui demande une préparation de surface fort poussée.According to yet a series of other interesting variants of the process of the invention, it is also possible to provide another solution to the problems posed by the metallic coating of special steels, for example Si steels and above all it makes it possible to minimize the influence. the quality of the preparation of the surface to be treated while making it possible to obtain coatings of constant thickness and satisfactory adhesion, as opposed to coating with a layer based on Zn-Al alloys which requires surface preparation strong push.

Suivant la caractéristique générique de cette dernière variante, le revêtement multicouche réalisé, présente une couche extérieure métallique polyphasée composée de phases enrichies en au moins deux métaux différents, le nombre de phases enriches en un métal déterminé étant avantageusement supérieur à un.According to the generic characteristic of this latter variant, the multilayer coating produced has a multi-phase metallic outer layer composed of phases enriched in at least two different metals, the number of phases enriched in a given metal being advantageously greater than one.

Entre le substrat et la couche extérieure, peuvent se trouver une ou plusieurs couches intermétalliques contenant notamment du fer ou être constituées d'un métal déterminé (ci-après appelé M1), tandis que la couche superficielle polyphasée comporte du métal M1, ainsi que un ou plusieurs autres métaux (ci-après appelés M2 ... Mn) formant avec M1 et/ou entre eux les différentes phases susindiquées.Between the substrate and the outer layer, there may be one or more intermetallic layers containing in particular iron or be made of a specific metal (hereinafter called M 1 ), while the polyphase surface layer comprises metal M 1 , thus that one or more other metals (hereinafter called M 2 ... M n ) forming with M 1 and / or between them the different phases mentioned above.

Plusieurs variantes intéressantes peuvent être citées à l'intérieur de la caractéristique générique susindiquée. On peut citer, pris isolément, ou suivant leurs combinaisons possibles. :

  • - le métal M, est constitué de zinc ou d'aluminium,
  • - la couche multiphase est constituée essentiellement de deux métaux, les autres n'intervenant pas pour plus de 5 % globalement,
  • - le métal M1 est du zinc et la couche polyphasée est constituée en majeure partie de zinc - aluminium,
  • - le substrat est recouvert de composés intermétalliques Fe-zn et/ou de zinc, tandis que la couche polyphasée comporte au moins une phase enrichie en Zn et au moins une phase enrichie en Al,
  • - le substrat est recouvert de zinc avec de 0,05 % à 0,4 % d'Al et de Pb (en quantité inférieure à 2 %),
  • - la couche polyphasée est composée de zinc avec de 3 % à 10 % d'Al, et peut contenir au plus 0,5 % globalement des éléments ci-après : Sb - Ce - Mg - La - Sn,
  • - la couche polyphasée est composée de zinc avec de l'aluminium et du magnésium, chacun de ces deux derniers éléments ne dépassant pas 10 %,
  • - la couche polyphasée est composée de zinc avec de 20 % à 80 % d'aluminium (de préférence de 50 % à 60 %), et peut contenir également jusqu'à 3 % de magnésium et jusqu'à 3 % de silicium.
Several interesting variants can be cited within the generic characteristic mentioned above. We can cite, taken in isolation, or according to their possible combinations. :
  • - the metal M, consists of zinc or aluminum,
  • - the multiphase layer consists essentially of two metals, the others accounting for no more than 5% overall,
  • - the metal M 1 is zinc and the polyphase layer consists mainly of zinc - aluminum,
  • the substrate is covered with intermetallic compounds Fe-zn and / or zinc, while the polyphase layer comprises at least one phase enriched in Z n and at least one phase enriched in Al,
  • - the substrate is covered with zinc with 0.05% to 0.4% Al and Pb (in an amount less than 2%),
  • the polyphase layer is composed of zinc with 3% to 10% of Al, and may contain at most 0.5% overall of the following elements: Sb - Ce - Mg - La - Sn,
  • - the polyphase layer is composed of zinc with aluminum and magnesium, each of the latter two elements not exceeding 10%,
  • - the multiphase layer is made of zinc with from 2 to 0% 8 0% aluminum (preferably from 50% to 60%), and may also contain up to 3% magnesium and up to 3% silicon .

Suivant les variantes dont la caractéristique générique a été .ci-dessus mentionnée, l'immersion relative à la ou aux couches intermétalliques peut conduire à un dépôt de la dite couche par voie électrolytique.According to the variants, the generic characteristic of which has been mentioned above, the immersion relating to the intermetallic layer or layers may lead to deposition of the said layer by electrolytic means.

Il ne sort toutefois pas du domaine relatif à ces variantes, que la mise en contact du substrat avec la couche de métal M1 et/ou la mise en contact de la couche extérieure polyphasée avec la couche immédiatement sousjacente se fait par dépôt sous forme fondue du métal M1 ou de la couche polyphasée, la fusion du matériau déposé étant réalisée de préférence immédiatement au moment du dépôt, sous atmosphère neutre et de préférence inerte (Ar), par exemple au moyen d'une torche plasma.However, it does not depart from the field relating to these variants, that bringing the substrate into contact with the metal layer M 1 and / or bringing the outer polyphase layer into contact with the immediately underlying layer is effected by deposit in molten form. of the metal M 1 or of the polyphase layer, the melting of the deposited material preferably being carried out immediately at the time of deposition, under a neutral and preferably inert atmosphere (Ar), for example by means of a plasma torch.

L'application des procédés repris à la description ci-dessus peut se faire, soit de façon continue, soit pièce par pièce.The application of the processes mentioned in the description above can be done either continuously or piece by piece.

Claims (14)

1. Procédé de revêtement à chaud d'un matériau de forme quelconque, mais se présentant de préférence sous forme de tube ou de tôle en acier, caractérisé en ce que le produit à traiter est immergé dans au moins deux bains métalliques dont les températures sont différentes.1. A method of hot coating a material of any shape, but preferably in the form of a tube or steel sheet, characterized in that the product to be treated is immersed in at least two metal baths whose temperatures are different. 2. Procédé suivant la revendication 1, caractérisé en ce qu'il consiste à utiliser un bain de plomb, suivi dans un stade ultérieur, par un bain d'alliage de zinc avec un ou plusieurs métaux.2. Method according to claim 1, characterized in that it consists in using a lead bath, followed in a later stage, by a zinc alloy bath with one or more metals. 3. Procédé suivant l'une ou l'autre des revendications 1 et 2, caractérisé en ce qu'il consiste à utiliser un bain métallique de Zn, suivi dans un stade ultérieur, par un bain d' alliage de zinc avec un ou plusieurs métaux.3. Method according to either of claims 1 and 2, characterized in that it consists in using a metal bath of Zn, followed in a later stage, by a bath of zinc alloy with one or more metals. 4. Procédé suivant une ou plusieurs des revendications 1 à 3, caractérisé en ce qu'il consiste à faire passer le produit à traiter au travers de trois bains métalliques contenus dans un même dispositif pourvu de moyens adéquats, ces bains étant composés respectivement dans l'ordre de progression du produit à traiter, de zinc, de plomb et d'un alliage de zinc et d'aluminium.4. Method according to one or more of claims 1 to 3, characterized in that it consists in passing the product to be treated through three metal baths contained in the same device provided with adequate means, these baths being composed respectively in the order of progress of the product to be treated, zinc, lead and a zinc and aluminum alloy. 5. Procédé suivant la revendication 1, caractérisé en ce que lorsque le second bain contient du zinc, le temps de séjour de la tôle d'acier dans le second bain n'est pas inférieure à son temps de séjour dans le premier bain.5. Method according to claim 1, characterized in that when the second bath contains zinc, the residence time of the steel sheet in the second bath is not less than its residence time in the first bath. 6. Procédé suivant la revendication 5, caractérisé en ce que le premier bain est du zinc ou du zinc-aluminium et le second est du zinc-aluminium pouvant être toutefois précédé d'un bain intercalaire dans du plomb fondu.6. Method according to claim 5, characterized in that the first bath is zinc or zinc-aluminum and the second is zinc-aluminum which can however be preceded by an intermediate bath in molten lead. 7. Procédé suivant l'une ou l'autre des revendications 3 à 6, caractérisé en ce que le bain d'alliage de zinc vérifie les relations ci-après :
Figure imgb0002
 7. Method according to either of claims 3 to 6, characterized in that the zinc alloy bath checks the following relationships:
Figure imgb0002
 8. Procédé suivant l'une ou l'autre des revendications 3 à 6, caractérisé en ce que le bain d'alliage de zinc vérifie les relations ci-après :
Figure imgb0003
 8. Method according to either of claims 3 to 6, characterized in that the zinc alloy bath checks the following relationships:
Figure imgb0003
 9. Procédé suivant l'une ou l'autre des revendications 3 à 6, caractérisé en ce que le bain d'alliage de zinc vérifie les relations ci-après :
Figure imgb0004
 9. Process according to either of Claims 3 to 6, characterized in that the zinc alloy bath checks the following relationships:
Figure imgb0004
 10. Procédé suivant l'une ou l'autre des revendications 1 à 9, caractérisé en ce qu'entre le substrat (en acier) et la couche extérieure se trouvent soit une ou plusieurs couches intermétalliques contenant du fer, soit un métal déterminé (M1), tandis que la couche superficielle polyphasée contient du métal M1, ainsi qu'un ou plusieurs autres métaux (M2... Mn) formant avec le métal M1 ou entre eux, les différentes phases susmentionnées.10. A method according to any one of claims 1 to 9, characterized in that between the substrate (steel) and the outer layer are either one or more intermetallic layers containing iron, or a specific metal ( M 1 ), while the polyphase surface layer contains metal M 1 , as well as one or more other metals (M 2 ... M n ) forming with the metal M 1 or between them, the different phases mentioned above. 11. Procédé suivant la revendication 10, caractérisé en ce que le métal M1 est du zinc ou de l'aluminium et la couche polyphasée composée en majeure partie de zinc-aluminium.11. Method according to claim 10, characterized in that the metal M 1 is zinc or aluminum and the polyphase layer composed mainly of zinc-aluminum. 12. Procédé suivant l'une ou l'autre des revendications 10 et 11, caractérisé en ce que la couche multiphase est constituée essentiellement de deux métaux, les autres n'intervenant pas pour plus de 5 % globalement.1 2 . Process according to either of Claims 10 and 11, characterized in that the multiphase layer consists essentially of two metals, the others not intervening for more than 5% overall. 13. Procédé suivant l'une ou l'autre des revendications 10 à 12, caractérisé en ce que les composés intermétalliques sont composés de Fe-Zn et/ou de zinc, tandis que la couche polyphasée comporte au moins une phase enrichie en zinc et au moins une phase enrichie en aluminium.13. Method according to either of claims 10 to 12, characterized in that the intermetallic compounds are composed of Fe-Zn and / or of zinc, while the polyphase layer comprises at least one phase enriched in zinc and at least one phase enriched with aluminum. 14. Procédé suivant l'une ou l'autre des revendications 10 à 13, caractérisé en ce que la couche polyphasée est composée de zinc vérifiant l'une ou l'autre des revendications 7 à 9.14. Method according to either of claims 10 to 13, characterized in that the polyphase layer is composed of zinc verifying one or the other of claims 7 to 9.
EP81200313A 1980-03-25 1981-03-20 Hot dip coating process Expired EP0037143B1 (en)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
BE6/47114A BE882430A (en) 1980-03-25 1980-03-25 HOT COATING PROCESS
BE47114 1980-03-25
BE6/47184A BE883725A (en) 1980-06-09 1980-06-09 PROTECTION METHOD BY MULTI-LAYERED MULTI-LAYER METAL COATINGS
BE47183 1980-06-09
BE6/47183A BE883724A (en) 1980-06-09 1980-06-09 PROCESS FOR HOT COATING OF SILICON STEELS
BE47184 1980-06-09

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Cited By (12)

* Cited by examiner, † Cited by third party
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EP0097487A2 (en) * 1982-06-17 1984-01-04 Uss Engineers And Consultants, Inc. Method of producing corrosion-resistant coatings on ferrous-base articles
EP0106021A2 (en) * 1982-06-23 1984-04-25 Bethlehem Steel Corporation Ferrous product having an alloy coating thereon of aluminium-zinc-magnesium-silicon, and method
FR2548216A1 (en) * 1983-06-28 1985-01-04 Fical Fils Cables Acier Lens SUPER-CORROSION RESISTANT COATED STEEL WIRE
FR2554831A1 (en) * 1983-11-15 1985-05-17 Thomson Csf Process for depositing a protective coating on metal articles
EP0148740A1 (en) * 1983-12-22 1985-07-17 CENTRE DE RECHERCHES METALLURGIQUES CENTRUM VOOR RESEARCH IN DE METALLURGIE Association sans but lucratif Method for hot coating and bath composition therefor
EP0337402A1 (en) * 1988-04-14 1989-10-18 Nippon Galvanizing Co., Ltd. High adhesion molten aluminum-zinc alloy plating process
GB2224041A (en) * 1988-09-02 1990-04-25 Verdun Hildreth Farnsworth Galvanising bath
EP0427389A1 (en) * 1989-11-06 1991-05-15 Dana Corporation Method of treating a ferrous component for subsequent metallurgical bonding to cast aluminum
ES2038885A1 (en) * 1990-04-13 1993-08-01 Centre Rech Metallurgique Process for the continuous dip coating of a steel strip
EP0647725A1 (en) * 1993-10-08 1995-04-12 Shinko Kosen Kogyo Kabushiki Kaisha Steel wire coated with Fe-Zn-A1 alloy and method for producing the same
WO2001055469A1 (en) * 2000-01-28 2001-08-02 Thyssenkrupp Stahl Ag Method for producing a steel strip which is provided with a zinc coating and zinc-coated steel strip
EP1225246A1 (en) * 1999-08-09 2002-07-24 Nippon Steel Corporation Zn-Al-Mg-Si ALLOY PLATED STEEL PRODUCT HAVING EXCELLENT CORROSION RESISTANCE AND METHOD FOR PREPARING THE SAME

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Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0097487A2 (en) * 1982-06-17 1984-01-04 Uss Engineers And Consultants, Inc. Method of producing corrosion-resistant coatings on ferrous-base articles
EP0097487A3 (en) * 1982-06-17 1984-09-12 Uss Engineers And Consultants, Inc. Method of producing corrosion-resistant coatings on ferrous-base articles
EP0106021A2 (en) * 1982-06-23 1984-04-25 Bethlehem Steel Corporation Ferrous product having an alloy coating thereon of aluminium-zinc-magnesium-silicon, and method
EP0106021A3 (en) * 1982-06-23 1984-09-12 Bethlehem Steel Corporation Ferrous product having an alloy coating thereon of aluminium-zinc-magnesium-silicon, and method
US4605598A (en) * 1983-06-28 1986-08-12 Fils Et Cables D'acier De Lens (Fical) Steel wire having superposed coatings resisting corrosion
FR2548216A1 (en) * 1983-06-28 1985-01-04 Fical Fils Cables Acier Lens SUPER-CORROSION RESISTANT COATED STEEL WIRE
EP0132424A1 (en) * 1983-06-28 1985-01-30 TREFILUNION Société Anonyme Corrosion-resistant steel wire
FR2554831A1 (en) * 1983-11-15 1985-05-17 Thomson Csf Process for depositing a protective coating on metal articles
EP0148740A1 (en) * 1983-12-22 1985-07-17 CENTRE DE RECHERCHES METALLURGIQUES CENTRUM VOOR RESEARCH IN DE METALLURGIE Association sans but lucratif Method for hot coating and bath composition therefor
EP0337402A1 (en) * 1988-04-14 1989-10-18 Nippon Galvanizing Co., Ltd. High adhesion molten aluminum-zinc alloy plating process
US5096666A (en) * 1988-09-02 1992-03-17 Farnsworth Verdun H Rare earth and aluminium containing galvanizing bath and method
GB2224041A (en) * 1988-09-02 1990-04-25 Verdun Hildreth Farnsworth Galvanising bath
EP0427389A1 (en) * 1989-11-06 1991-05-15 Dana Corporation Method of treating a ferrous component for subsequent metallurgical bonding to cast aluminum
ES2038885A1 (en) * 1990-04-13 1993-08-01 Centre Rech Metallurgique Process for the continuous dip coating of a steel strip
EP0647725A1 (en) * 1993-10-08 1995-04-12 Shinko Kosen Kogyo Kabushiki Kaisha Steel wire coated with Fe-Zn-A1 alloy and method for producing the same
EP1225246A1 (en) * 1999-08-09 2002-07-24 Nippon Steel Corporation Zn-Al-Mg-Si ALLOY PLATED STEEL PRODUCT HAVING EXCELLENT CORROSION RESISTANCE AND METHOD FOR PREPARING THE SAME
EP1225246A4 (en) * 1999-08-09 2005-02-09 Nippon Steel Corp Zn-Al-Mg-Si ALLOY PLATED STEEL PRODUCT HAVING EXCELLENT CORROSION RESISTANCE AND METHOD FOR PREPARING THE SAME
CN100334250C (en) * 1999-08-09 2007-08-29 新日本制铁株式会社 Zn-Al-Mg-Si alloy plated steel product having excellent corrosion resistance and method for preparing the same
WO2001055469A1 (en) * 2000-01-28 2001-08-02 Thyssenkrupp Stahl Ag Method for producing a steel strip which is provided with a zinc coating and zinc-coated steel strip

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