EP0254703A1 - Process and apparatus for electroplating zinc on a steel strip - Google Patents

Process and apparatus for electroplating zinc on a steel strip Download PDF

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Publication number
EP0254703A1
EP0254703A1 EP87870098A EP87870098A EP0254703A1 EP 0254703 A1 EP0254703 A1 EP 0254703A1 EP 87870098 A EP87870098 A EP 87870098A EP 87870098 A EP87870098 A EP 87870098A EP 0254703 A1 EP0254703 A1 EP 0254703A1
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EP
European Patent Office
Prior art keywords
strip
anodes
electrolyte
drum
installation according
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EP87870098A
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German (de)
French (fr)
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EP0254703B1 (en
Inventor
Joseph Labye
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Delloye-Matthieu Toleries SA
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Delloye-Matthieu Toleries SA
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D7/00—Electroplating characterised by the article coated
    • C25D7/06—Wires; Strips; Foils
    • C25D7/0614—Strips or foils

Definitions

  • the invention relates to an electrogalvanizing process and installation for obtaining on a steel strip a deposit of zinc with a compact monooriented crystal structure.
  • the qualities of the electrogalvanized sheets depend on the morphology of the zinc coating, which itself depends on the composition of the electrolytic fluid, the dynamic conditions of the electrolytic fluid, the density of the current applied and the type of electrolytic cell used.
  • this device does not make it possible to obtain a deposit of zinc with a compact mono-oriented crystal structure. This is due to the fact that not only is the electrolyte flow not unidirectional, but also because the distribution of electric current between anodes and cathode is not uniform.
  • the causes of this non-uniformity are as follows: - heterogeneity of the anodes; - electrical resistance of the steel strip; - variable oxygen content of the electrolytic liquid, and - variations in the position of the anodes.
  • the anodes consist of a cast lead-silver alloy body with a copper core.
  • the connection between the copper and the alloy is not always perfect, so that the resistance to the passage of current may differ from one anode to another;
  • the resistance of the steel strip varies throughout it, so that the current passing through the lowest placed anode meets a greater resistance than that passing through the highest placed anode.
  • Oxygen is released in large quantities on the anodes.
  • the oxygen concentration in the electrolyte increases from the lowest anode to the highest anode and there are therefore different conditions for the current to flow from one anode to another.
  • the position of the anodes is obviously variable from one to the other.
  • US Pat. No. 3,900,383 discloses an electrogalvanizing drum provided with several conductive segments insulated from one another. These segments are arranged so as to be in electrical contact with a metal strip immersed in an electrolytic bath. A switch connects the segments one after the other to a source of electric current, so that only the segments of the drum which are fully in contact with the strip are supplied with current. This drum prevents the formation of electric arcs between the strip and the drum.
  • This switch can also be made up of independent cathodes connected to anodes by electrical sources, so as to allow the passage of different electrical currents between cathodes and anodes.
  • electrogalvanizing current can be, for example, gradually increased.
  • This device also makes it possible to obtain a current flow which increases first and then decreases in the electrolytic cell.
  • This known device does not make it possible to obtain in all points the same density of electrolysis current as well as to obtain on the strip a deposit of zinc with a compact mono-oriented structure.
  • the device and the method according to the invention aim to remedy the aforementioned drawbacks.
  • the process according to the invention in which a steel strip acting as a cathode is passed in front of a series of anodes, while a charged electrolyte current is circulated between the cathode and the anodes of zinc, is characterized in that each anode is supplied independently of the others with electric current and in that the voltage of each anode is adjusted to pass a given quantity of electric current through each anode to obtain, from each of these anodes, the same density of the electrolysis current at all points.
  • the flow of electrolyte circulating between the strip and the anodes is adjusted so as to obtain a determined relative speed of the electrolyte relative to the strip, in order to obtain a deposit on the strip.
  • zinc with compact mono-oriented structure is adjusted so as to obtain a determined relative speed of the electrolyte relative to the strip, in order to obtain a deposit on the strip.
  • the electrogalvanizing installation according to the invention for continuously coating a steel strip with a zinc deposit which comprises, as is known, an insulating drum around which the strip serving cathode, while in front of the strip and separated from it by a continuous flow of electrolyte containing zinc, is a series of anodes placed one next to the other and mounted at the end of branches of an electric circuit delivering in each of them a direct current, is characterized in that said circuit branches are branched into a number of branches, equal to that of the anodes, each branch containing an individual assembly each comprising a current rectifier and an independent voltage adjustment device, making it possible to obtain that the current delivered in each branch corresponds to the same current density in each of the branches respectively comprising an anode and a corresponding portion of the steel strip which moves in front she.
  • the anodes are distributed around the circumference of the drum and surrounded by an external envelope so as to constitute around the drum two channels symmetrical with respect to a vertical plane passing through the axis of the drum , these channels being traversed by an electrolyte containing zinc, the supply of electrolyte being made by an upper end of one of the channels, and the discharge of the spent electrolyte, by the end of the other.
  • a preferred embodiment of the installation according to the invention is an installation in which below the drum is located, between the two lower ends of the two symmetrical channels, a vane rotor driven by a motor.
  • FIG. 1 we see in cross section a drum 1 of insulating material, freely rotating about its horizontal axis.
  • the steel strip 2 delivered by a roller 3 and returned to a roller 4 in an arrangement which makes it possible to hold the strip 2 stretched around the drum 1.
  • the strip 2 closes the rectifier circuit 9 by its brain 2 brain and the roller assembly 11, and the rectifier circuit 10 by its brain 2 ⁇ and the roller assembly 12.
  • the lower part of the drum 1 is surrounded of an envelope 13 forming around the drum 1 a pair of channels 14 and 15 joined at their lower part. At the meeting point of the two channels 14 and 15 opens a pipe 16 for supplying the system with electrolyte.
  • the electrolyte flows according to the arrows F1, F2.
  • each group of anodes 5, 6, supposed to have eight anodes is supplied by a current of 10,000 amperes
  • a current of 1250 amps one would expect that, in each of the branches of the circuit, leading to any anode 5 ⁇ , 6 ⁇ , circulates a current of 1250 amps.
  • the currents flowing in the different branches present, compared to the average value of 1250 amperes, percentage deviations indicated in the second line of Table I below, the first line of this table containing the enumeration of the various anodes input 1E, 2E, etc ..., and various output anodes 1S, 2S, etc ...
  • each of the anodes 5 ⁇ and 6 ⁇ being mounted in a branch of the circuit 17 containing an independent current source 18, adjusted individually to obtain in each electrolysis cell the same current density, this is that is to say that in each branch 17 of the circuit will circulate a current of the same intensity, of 1250 amperes for example.
  • the various anodes 5 ⁇ and 6 ⁇ are separated from each other by a layer of insulating material 27. The voltage of each anode is adjusted so as to allow the passage of a determined quantity of electric current through each anode to obtain from each of them the same density of electrolysis current at all points.
  • this rotor 19 comprises symmetrical radial vanes 22, the distance between the ends of the vanes 22 and the periphery of the drum 1 being the same as the distance from the anodes 5 ⁇ , 6 ⁇ to this drum 1.
  • the function of this rotor 19 is to provide the electrolyte which descends along one of the channels, for example 15, with additional energy for raising the electrolyte in the other channel, either here 14, the blades 22 being designed to distribute this additional energy uniformly over the entire width of the channel and guarantee a homogeneous circulation of the electrolyte downstream of the rotor 19, thereby creating symmetrical flow conditions (see arrows F and F ⁇ in Figure 3) with respect to a vertical plane passing through the axis of the drum 1.
  • the lower ends of the channels 14, 15 are limited, on the side opposite that of the drum 1, by deflecting surfaces or ramps 23, 24 whose extreme edge, such as 25 in FIGS. 4 and 5, extends parallel to the axis 20 of the rotor 19 and over the same length as the latter.
  • This edge 25 can advantageously be wavy (FIG. 6).
  • the arrangement of these ramps 23, 24 is still symmetrical with respect to the vertical plane passing through the axis 20 of the rotor 19 and through the axis of the drum 1, so that the operation of the device is the same, regardless of the direction of rotation of the drum 1.
  • the speed of flow of the liquid downstream of these can be increased or decreased.
  • ramp or the converging nozzles 26 can be mounted on the left side of the drum 1 rather than on the right side of the drum as shown in FIGS. 2 and 3.
  • the rotor 19 intervenes to uniformly distribute the additional positive or negative energy which must be communicated to the electrolyte to guarantee a relative speed uniformly distributed downstream of the rotor 19, to satisfy, according to the tape running speed and the current density, under the conditions of a zinc deposit of the compact mono-oriented type.
  • the process according to the invention therefore consists: to obtain the same density of the electrolysis current at all points by means of an independent supply of each anode 5 ⁇ , 6 ⁇ with electric current, and by adjusting the voltage of each anode and - To adjust the relative speed of the fluid with respect to the strip 2 to produce compact mono-oriented crystal structures.
  • the relative speed of the fluid with respect to the strip 2 can be modified: - by changing the electrolyte flow in the passages 14, 15, that is to say by changing the speed of rotation of the pump 28 (see Figures 2 and 3) bringing the electrolyte through the conduit 29 and the ramp or the nozzle converge 26 in the cell and / or - by changing the running speed of the steel strip 2, that is to say by changing the speed of the motor 30 driving in rotation a drum 31 on which the steel strip 2 is wound up (see figure 3).

Abstract

The steel strip (2) acts as a cathode facing a series of anodes (5, 6), while a stream of electrolyte carrying zinc is circulated between the cathode and the anodes (5', 6'). Each anode (5', 6') is fed independently of the others and the quantity of current passing through each anode (5', 6') is adjusted to obtain, from each of them, the same electrolysis current density at all points, in order to obtain on the strip (2) a zinc deposit of a compact, monooriented crystalline structure. The invention also relates to an apparatus for applying this process. <IMAGE>

Description

L'invention concerne un procédé et une installation d'électrozingage pour obtenir sur une bande d'acier un dépôt de zinc à structure cristalline mono­orientée compacte.The invention relates to an electrogalvanizing process and installation for obtaining on a steel strip a deposit of zinc with a compact monooriented crystal structure.

L'industrie, notamment l'industrie automobile, fait usage de quantités de plus en plus grandes de tôles d'acier électrozinguées.The industry, in particular the automobile industry, is making use of increasingly large quantities of galvanized steel sheets.

Les qualités des tôles électrozinguées dépendent de la morphologie du revêtement de zinc, laquelle dépend elle-même de la composition du fluide électrolytique, des conditions dynamiques du fluide électrolytique, de la densité du courant appliqué et du type de cellule électrolytique utilisé.The qualities of the electrogalvanized sheets depend on the morphology of the zinc coating, which itself depends on the composition of the electrolytic fluid, the dynamic conditions of the electrolytic fluid, the density of the current applied and the type of electrolytic cell used.

C'est de cette morphologie que dépendent principalement les qualités de résistance à la corrosion de ces tôles. Il est particulièrement intéressant de réaliser des structures cristallines mono-orientées compactes du dépôt de zinc.It is mainly on this morphology that the corrosion resistance qualities of these sheets depend. It is particularly interesting to produce compact mono-oriented crystal structures of the zinc deposit.

Il est connu de procéder à l'electrozingage d'une bande d'acier au moyen d'un appareillage comprenant essentiellement un tambour rotatif de matière isolante autour duquel est entraînée la bande d'acier à électrozinguer, une série d'anodes disposées périphériquement autour d'une partie du tambour et un flot d'électrolyte (contenant le zinc, sous forme de sel) créé entre ces anodes et la bande d'acier jouant le rôle de cathode. Dans ce dispositif connu, les anodes sont disposées côte à côte et montées en parallèle.It is known to electro-galvanize a steel strip by means of an apparatus essentially comprising a rotating drum of insulating material around which the steel strip to be electro-galvanized is driven, a series of anodes disposed peripherally around of a part of the drum and a flow of electrolyte (containing zinc, in the form of salt) created between these anodes and the steel strip playing the role of cathode. In this known device, the anodes are arranged side by side and mounted in parallel.

On a constaté que ce dispositif ne permet pas d'obtenir un dépôt de zinc à structure cristalline mono-­orientée compacte. Ceci provient du fait que non seulement le flot d'électrolyte n'est pas unidirectionnel, mais aussi du fait que la répartition du courant électrique entre anodes et cathode n'est pas uniforme. Les causes de cette non-uniformité sont les suivantes:
- hétérogénéité des anodes;
- résistance electrique de la bande d'acier;
- teneur variable en oxygène du liquide électrolytique, et
- variations dans la position des anodes.It has been found that this device does not make it possible to obtain a deposit of zinc with a compact mono-oriented crystal structure. This is due to the fact that not only is the electrolyte flow not unidirectional, but also because the distribution of electric current between anodes and cathode is not uniform. The causes of this non-uniformity are as follows:
- heterogeneity of the anodes;
- electrical resistance of the steel strip;
- variable oxygen content of the electrolytic liquid, and
- variations in the position of the anodes.

Les anodes sont constituées d'un corps coulé en alliage plomb-argent avec une âme de cuivre. La liaison entre le cuivre et l'alliage n'est pas toujours parfaite, de sorte que la résistance au passage du courant peut différer d'une anode à l'autre;The anodes consist of a cast lead-silver alloy body with a copper core. The connection between the copper and the alloy is not always perfect, so that the resistance to the passage of current may differ from one anode to another;

La résistance de la bande d'acier varie tout au long de celle-ci, de sorte que le courant passant par l'anode placée le plus bas rencontre une résistance plus grande que celui qui passe par l'anode placée le plus haut.The resistance of the steel strip varies throughout it, so that the current passing through the lowest placed anode meets a greater resistance than that passing through the highest placed anode.

De l'oxygène se dégage en grandes quantités sur les anodes. La concentration en oxygène dans l'électrolyte augmente de l'anode placée le plus bas à l'anode placée le plus haut et il y a donc des conditions différentes de passage du courant d'une anode à l'autre.Oxygen is released in large quantities on the anodes. The oxygen concentration in the electrolyte increases from the lowest anode to the highest anode and there are therefore different conditions for the current to flow from one anode to another.

La position des anodes est evidemment variable de l'une à l'autre.The position of the anodes is obviously variable from one to the other.

Quel que soit le débit du flot d'électrolyte et la manière dont celui-ci est produit entre la tôle d'acier constituant la cathode et la série d'anodes, il y aura donc inévitablement une variation des conditions de dépôt du zinc sur la bande, d'une anode à l'autre.Whatever the flow rate of the electrolyte flow and the way in which this is produced between the steel sheet constituting the cathode and the series of anodes, there will therefore inevitably be a variation in the conditions of deposition of zinc on the strip, from one anode to another.

On connaît par le brevet US 3.900.383 un tambour d'électrozingage muni de plusieurs segments conducteurs isolés l'un de l'autre. Ces segments sont disposés de manière à être en contact électrique avec une bande métallique immergée dans un bain électrolytique. Un commutateur relie les segments l'un après l'autre à une source de courant électrique, de sorte que seuls les segments du tambour qui sont entièrement en contact avec la bande sont alimentés en courant. Ce tambour permet d'éviter la formation d'arcs électriques entre la bande et le tambour.US Pat. No. 3,900,383 discloses an electrogalvanizing drum provided with several conductive segments insulated from one another. These segments are arranged so as to be in electrical contact with a metal strip immersed in an electrolytic bath. A switch connects the segments one after the other to a source of electric current, so that only the segments of the drum which are fully in contact with the strip are supplied with current. This drum prevents the formation of electric arcs between the strip and the drum.

Ce commutateur peut également être constitué de cathodes indépendantes reliées à des anodes par des sources électriques, de manière à permettre le passage de courants électriques différents entre cathodes et anodes.This switch can also be made up of independent cathodes connected to anodes by electrical sources, so as to allow the passage of different electrical currents between cathodes and anodes.

Ainsi le courant d'électrozingage peut être, par exemple, progressivement augmenté.Thus the electrogalvanizing current can be, for example, gradually increased.

Ce dispositif permet également d'obtenir un flux de courant d'abord croissant et ensuite décroissant dans la cellule électrolytique.This device also makes it possible to obtain a current flow which increases first and then decreases in the electrolytic cell.

Ce dispositif connu ne permet pas d'obtenir en tous points une même densité de courant d'electrolyse ainsi que d'obtenir sur la bande un dépôt de zinc à structure mono-orientée compacte.This known device does not make it possible to obtain in all points the same density of electrolysis current as well as to obtain on the strip a deposit of zinc with a compact mono-oriented structure.

Le dispositif et le procédé suivant l'invention visent à remédier aux inconvénients précités.The device and the method according to the invention aim to remedy the aforementioned drawbacks.

Le procédé suivant l'invention, dans lequel on fait défiler une bande d'acier jouant le rôle de cathode en face d'une série d'anodes, tandis qu'on fait circuler entre la cathode et les anodes un courant d'électrolyte chargé de zinc, se caractérise en ce qu'on alimente chaque anode indépendamment des autres en courant électrique et en ce qu'on règle la tension de chaque anode pour faire passer une quantité de courant électrique déterminée à travers chaque anode pour obtenir, à partir de chacune de ces anodes, une même densité du courant d'électrolyse en tous points.The process according to the invention, in which a steel strip acting as a cathode is passed in front of a series of anodes, while a charged electrolyte current is circulated between the cathode and the anodes of zinc, is characterized in that each anode is supplied independently of the others with electric current and in that the voltage of each anode is adjusted to pass a given quantity of electric current through each anode to obtain, from each of these anodes, the same density of the electrolysis current at all points.

Dans une forme avantageuse du procédé suivant l'invention, on règle le flot d'électrolyte circulant entre la bande et les anodes de manière à obtenir une vitesse relative déterminée de l'électrolyte par rapport à la bande, pour obtenir sur la bande un dépôt de zinc à structure mono-orientée compacte.In an advantageous form of the process according to the invention, the flow of electrolyte circulating between the strip and the anodes is adjusted so as to obtain a determined relative speed of the electrolyte relative to the strip, in order to obtain a deposit on the strip. zinc with compact mono-oriented structure.

L'installation d'électrozingage suivant l'invention pour revêtir en continu une bande d'acier d'un dépôt de zinc et qui comprend, comme il est connu, un tambour isolant autour duquel passe la bande servant de cathode, tandis qu'en face de la bande et séparées de celle-ci par un flot continu d'électrolyte contenant du zinc, se trouve une série d'anodes placées les unes à côté des autres et montées à l'extrémité de branches d'un circuit électrique débitant dans chacune d'elles un courant continu, est caractérisée en ce que lesdites branches de circuit sont ramifiées en un nombre de branches, égal à celui des anodes, chaque branche contenant un ensemble individuel comprenant chacun un redresseur de courant et un dispositif indépendant de réglage de la tension, permettant d'obtenir que le courant débité dans chaque branche corresponde à une même densité de courant dans chacune des branches comprenant respectivement une anode et une portion correspondante de la bande d'acier qui se déplace devant elle.The electrogalvanizing installation according to the invention for continuously coating a steel strip with a zinc deposit and which comprises, as is known, an insulating drum around which the strip serving cathode, while in front of the strip and separated from it by a continuous flow of electrolyte containing zinc, is a series of anodes placed one next to the other and mounted at the end of branches of an electric circuit delivering in each of them a direct current, is characterized in that said circuit branches are branched into a number of branches, equal to that of the anodes, each branch containing an individual assembly each comprising a current rectifier and an independent voltage adjustment device, making it possible to obtain that the current delivered in each branch corresponds to the same current density in each of the branches respectively comprising an anode and a corresponding portion of the steel strip which moves in front she.

Dans une forme de réalisation particulière de l'installation, les anodes sont réparties autour de la circonférence du tambour et entourées par une enveloppe extérieure en sorte de constituer autour du tambour deux canaux symétriques par rapport à un plan vertical passant par l'axe du tambour, ces canaux étant traversés par un électrolyte contenant du zinc, l'alimentation en électrolyte se faisant par une extrémité supérieure de l'un des canaux, et l'évacuation de l'électrolyte usé, par l'extrémité de l'autre.In a particular embodiment of the installation, the anodes are distributed around the circumference of the drum and surrounded by an external envelope so as to constitute around the drum two channels symmetrical with respect to a vertical plane passing through the axis of the drum , these channels being traversed by an electrolyte containing zinc, the supply of electrolyte being made by an upper end of one of the channels, and the discharge of the spent electrolyte, by the end of the other.

Une forme de réalisation préférée de l'installation suivant l'invention est une installation dans laquelle en dessous du tambour se trouve, entre les deux extrémités inférieures des deux canaux symétriques, un rotor à aubes entraîné par un moteur.A preferred embodiment of the installation according to the invention is an installation in which below the drum is located, between the two lower ends of the two symmetrical channels, a vane rotor driven by a motor.

Les dessins joints au présent mémoire font mieux comprendre l'invention.The drawings attached to this memo do better understand the invention.

On y voit en

  • - figure 1, représentés schématiquement, les traits essentiels d'une installation connue;
  • - figure 2, une vue schématique d'une installation suivant l'invention;
  • - figure 3, une vue analogue à celle de la figure 2, modifiée suivant un développement de l'invention, dans une forme de réalisation préférée;
  • - figure 4, le détail d'un rotor à aubes et de rampes qui lui sont associées, et
  • - figures 5 et 6, en perspective, des formes de rampes.
We see in
  • - Figure 1, shown schematically, the essential features of a known installation;
  • - Figure 2, a schematic view of an installation according to the invention;
  • - Figure 3, a view similar to that of Figure 2, modified according to a development of the invention, in a preferred embodiment;
  • - Figure 4, the detail of a vane rotor and ramps associated with it, and
  • - Figures 5 and 6, in perspective, forms of ramps.

A la figure 1, on voit en coupe transversale un tambour 1 en matière isolante, tournant librement autour de son axe horizontal. Autour du tambour 1 se trouve la bande d'acier 2 débitée par un rouleau 3 et renvoyée sur un rouleau 4 dans une disposition qui permet de tenir la bande 2 tendue autour du tambour 1. En face du tambour 1, à sa partie inférieure, se trouvent, disposés de part et d'autre et répartis périphériquement de la même façon, deux groupes d'anodes accolées 5 et 6. Ces anodes sont alimentées respectivement par des circuits 7 et 8 de courant continu, dont les sources sont indiquées par 9 et 10. La bande 2 ferme le circuit du redresseur 9 par son brain 2ʹ et l'ensemble de rouleaux 11, et le circuit du redresseur 10 par son brain 2ʺ et l'ensemble de rouleaux 12. La partie inférieure du tambour 1 est entourée d'une enveloppe 13 formant autour du tambour 1 une paire de canaux 14 et 15 réunis à leur partie inférieure. Au point de rencontre des deux canaux 14 et 15 débouche un tuyau 16 d'alimentation du système en électrolyte. L'électrolyte s'écoule suivant les flèches F₁, F₂.In Figure 1, we see in cross section a drum 1 of insulating material, freely rotating about its horizontal axis. Around the drum 1 is the steel strip 2 delivered by a roller 3 and returned to a roller 4 in an arrangement which makes it possible to hold the strip 2 stretched around the drum 1. In front of the drum 1, at its lower part, are located, arranged on either side and distributed peripherally in the same way, two groups of contiguous anodes 5 and 6. These anodes are supplied respectively by DC circuits 7 and 8, the sources of which are indicated by 9 and 10. The strip 2 closes the rectifier circuit 9 by its brain 2 brain and the roller assembly 11, and the rectifier circuit 10 by its brain 2ʺ and the roller assembly 12. The lower part of the drum 1 is surrounded of an envelope 13 forming around the drum 1 a pair of channels 14 and 15 joined at their lower part. At the meeting point of the two channels 14 and 15 opens a pipe 16 for supplying the system with electrolyte. The electrolyte flows according to the arrows F₁, F₂.

Comme les électrodes de l'ensemble d'entrée 5 et de l'ensemble de sortie 6 sont alimentées en parallèle, on se trouve confronté avec les problèmes évoqués dans l'introduction de description. C'est dire qu'il est impossible d'obtenir partout la même densité de courant et, par conséquent, qu'il est exclu de réaliser sur la bande d'acier un dépôt de zinc à structure cristalline mono-orientée compacte.As the electrodes of the input assembly 5 and the output assembly 6 are supplied in parallel, we are faced with the problems mentioned in the introduction to the description. This means that it is impossible to obtain the same current density everywhere and, consequently, that it is excluded to carry out on the steel strip a deposit of zinc with a compact mono-oriented crystal structure.

Si, par exemple, chaque groupe d'anodes 5, 6, supposé comporter huit anodes, est alimenté par un courant de 10.000 ampères, on pourrait s'attendre à ce que, dans chacune des branches du circuit, aboutissant à une anode quelconque 5ʹ, 6ʹ, circule un courant de 1250 ampères. On trouve cependant que les courants circulant dans les différentes branches présentent, par rapport à la valeur moyenne de 1250 ampères, des écarts en pourcentage indiqués à la deuxième ligne du Tableau I suivant, la première ligne de ce tableau contenant l'énumération des diverses anodes d'entrée 1E, 2E, etc..., et des diverses anodes de sortie 1S, 2S, etc...

Figure imgb0001
If, for example, each group of anodes 5, 6, supposed to have eight anodes, is supplied by a current of 10,000 amperes, one would expect that, in each of the branches of the circuit, leading to any anode 5ʹ , 6ʹ, circulates a current of 1250 amps. However, it is found that the currents flowing in the different branches present, compared to the average value of 1250 amperes, percentage deviations indicated in the second line of Table I below, the first line of this table containing the enumeration of the various anodes input 1E, 2E, etc ..., and various output anodes 1S, 2S, etc ...
Figure imgb0001

Il est évidemment impossible de faire varier le débit du fluide électrolytique au droit de chaque anode, pour réaliser ainsi une densité de courant partout la même. C'est donc sur le circuit électrique, suivant l'invention, que l'on doit agir pour obtenir une densité de courant uniforme.It is obviously impossible to vary the flow rate of the electrolytic fluid at the level of each anode, thereby achieving a current density everywhere the same. It is therefore on the electrical circuit, according to the invention, that action must be taken to obtain a uniform current density.

Dans l'installation suivant l'invention, dont le principe est représenté sur la figure 2, on voit qu'au lieu de deux groupes d'anodes accolées 5 et 6, on prévoit dans les passages 14 et 15, une série d'anodes 5ʹ et 6ʹ séparées les unes des autres, chacune des anodes 5ʹ et 6ʹ étant montée dans une branche du circuit 17 contenant une source de courant indépendante 18, réglée individuellement pour obtenir dans chaque cellule d'électrolyse la même densité de courant, c'est-à-dire que dans chaque branche 17 du circuit circulera un courant d'une même intensité, de 1250 ampères par exemple. Les diverses anodes 5ʹ et 6ʹ sont séparées l'une de l'autre par une couche de matière isolante 27. La tension de chaque anode est réglée de manière à permettre le passage d'une quantité déterminée de courant électrique à travers chaque anode pour obtenir à partir de chacune d'elles une même densité de courant d'électrolyse en tous points.In the installation according to the invention, the principle of which is shown in FIG. 2, it can be seen that instead of two groups of contiguous anodes 5 and 6, a series of anodes is provided in passages 14 and 15 5ʹ and 6ʹ separated from each other, each of the anodes 5ʹ and 6ʹ being mounted in a branch of the circuit 17 containing an independent current source 18, adjusted individually to obtain in each electrolysis cell the same current density, this is that is to say that in each branch 17 of the circuit will circulate a current of the same intensity, of 1250 amperes for example. The various anodes 5ʹ and 6ʹ are separated from each other by a layer of insulating material 27. The voltage of each anode is adjusted so as to allow the passage of a determined quantity of electric current through each anode to obtain from each of them the same density of electrolysis current at all points.

Il est connu que lorsqu'on réalise des structures cristallines mono-orientées compactes, il existe entre la densité de courant i et le nombre de Reynolds Re caractérisant l'écoulement du fluide par rapport à la bande d'acier 2, une relation i = f(Re) et plus précisément une relation de proportionnalité
i=KcRe 0,7
dans laquelle K est une constante dépendant de divers facteurs, notamment du type de morphologie à obtenir et de la forme géométrique des cellules, tandis que c désigne la concentration en zinc de l'électrolyte. Le nombre de Reynolds est égal à

Figure imgb0002
où Vr est la vitesse relative du fluide par rapport à la bande 2; D est le diamètre hydraulique équivalent du conduit à travers lequel passe le fluide électrolytique et ν est la viscosité cinématique de ce fluide.It is known that when compact mono-oriented crystal structures are produced, there exists between the current density i and the Reynolds number R e characterizing the flow of the fluid relative to the steel strip 2, a relation i = f (R e ) and more precisely a proportionality relation
i = KcR e 0.7
in which K is a constant depending on various factors, in particular the type of morphology to be obtained and of the geometric shape of the cells, while c denotes the zinc concentration of the electrolyte. Reynolds number is equal to
Figure imgb0002
 where V r is the relative speed of the fluid with respect to the strip 2; D is the equivalent hydraulic diameter of the conduit through which the electrolytic fluid passes and ν is the kinematic viscosity of this fluid.

On a évidemment:

Figure imgb0003
où Q est le débit du fluide électrolytique et S est la section du conduit de passage du fluide. Cette section est égale au produit de la longueur du tambour 1 et de la distance entre une anode quelconque 5ʹ, 6ʹ et la bande d'acier 2; le signe ± est à choisir suivant le sens d'écoulement du fluide par rapport au sens du défilement de la bande 2. Ce défilement a lieu à une vitesse indiquée par VD.We obviously have:
Figure imgb0003
 where Q is the flow rate of the electrolytic fluid and S is the cross section of the fluid passage duct. This section is equal to the product of the length of the drum 1 and the distance between any anode 5ʹ, 6ʹ and the steel strip 2; the sign ± is to be chosen according to the direction of flow of the fluid with respect to the direction of travel of the strip 2. This travel takes place at a speed indicated by V D.

On a donc en définitive une relation de la forme i = f(Q) qui montre que, toutes choses étant égales par ailleurs, on pourra agir sur la grandeur du débit Q pour obtenir une structure cristalline mono-orientée compacte déterminée.There is therefore ultimately a relation of the form i = f (Q) which shows that, all other things being equal, we can act on the magnitude of the flow rate Q to obtain a determined compact mono-oriented crystal structure.

Pour que la condition i = Kc(Re)-0,7 soit partout satisfaite, il est indispensable que le sens de l'écoulement du flot d'électrolyte autour de la bande servant de cathode soit partout le même, et que la vitesse relative de ce flot par rapport à la bande 2 soit aussi partout la même.So that the condition i = Kc (R e ) -0.7 is everywhere satisfied, it is essential that the direction of flow of the electrolyte flow around the strip serving as the cathode is everywhere the same, and that the relative speed of this flow with respect to the strip 2 is also everywhere the same.

Dans une installation telle que celle de la figure 2 où il y a, de part et d'autre du tambour 1, chaque fois un canal pour l'électrolyte, il faut donc que l'un de ces canaux, 14, par exemple, soit alimenté en électrolyte à sa partie supérieure et que l'électrolyte usé s'échappe de l'autre canal 15 par son extrémité supérieure. Cependant, sauf dispositions spéciales les conditions d'écoulement dans le second canal pourraient ne pas être égales à celles qui règnent dans le premier. Pour parer à cet inconvénient, on peut réaliser le système suivant la figure 3 où l'on voit qu'en dessous du tambour 1, entre les extrémités inférieures des canaux 14, 15, on a installé un rotor 19 à aubes 22. Ce rotor dont l'arbre 20 est entraîné en bout par un moteur 21 à vitesse variable (voir figure 4) comporte des aubes radiales symétriques 22, la distance entre les extrémités des aubes 22 et le pourtour du tambour 1 étant la même que la distance des anodes 5ʹ, 6ʹ à ce tambour 1. La fonction de ce rotor 19 est d'apporter à l'électrolyte qui descend suivant l'un des canaux, par exemple 15, une énergie supplémentaire pour faire remonter l'électrolyte dans l'autre canal, soit ici 14, les aubes 22 étant conçues pour distribuer cette énergie supplémentaire de façon uniforme sur toute la largeur du canal et garantir une circulation homogène de l'électrolyte en aval du rotor 19, en créant ainsi des conditions d'écoulement symétriques (voir flèches F et Fʺ à la figure 3) par rapport à un plan vertical passant par l'axe du tambour 1. Les extrémités inférieures des canaux 14, 15 sont limitées, du côté opposé à celui du tambour 1, par des surfaces déflectrices ou rampes 23,24 dont l'arête extrême, telle que 25 sur les figures 4 et 5, s'étend parallèlement à l'axe 20 du rotor 19 et sur la même longueur que celui-ci. Cette arête 25 peut être avantageusement ondulée (figure 6). La disposition de ces rampes 23, 24 est encore symétrique par rapport au plan vertical passant par l'axe 20 du rotor 19 et par l'axe du tambour 1, afin que le fonctionnement du dispo­sitif soit le même, quel que soit le sens de rotation du tambour 1. Suivant le sens d'inclinaison de la surface limite 23ʹ, 24ʹdes rampes 23, 24, on peut augmenter ou diminuer la vitesse d'écoulement du liquide en aval de celles-ci.In an installation such as that of FIG. 2 where there is, on either side of the drum 1, each time a channel for the electrolyte, it is therefore necessary that one of these channels, 14, for example, is supplied with electrolyte at its upper part and the spent electrolyte escapes from the other channel 15 through its upper end. However, unless there are special provisions, the flow conditions in the second channel may not be equal to those prevailing in the first. To overcome this drawback, the system can be produced according to FIG. 3 where it can be seen that below the drum 1, between the lower ends of the channels 14, 15, a rotor 19 with blades 22 has been installed. This rotor whose shaft 20 is driven at the end by a variable speed motor 21 (see FIG. 4) comprises symmetrical radial vanes 22, the distance between the ends of the vanes 22 and the periphery of the drum 1 being the same as the distance from the anodes 5ʹ, 6ʹ to this drum 1. The function of this rotor 19 is to provide the electrolyte which descends along one of the channels, for example 15, with additional energy for raising the electrolyte in the other channel, either here 14, the blades 22 being designed to distribute this additional energy uniformly over the entire width of the channel and guarantee a homogeneous circulation of the electrolyte downstream of the rotor 19, thereby creating symmetrical flow conditions (see arrows F and Fʺ in Figure 3) with respect to a vertical plane passing through the axis of the drum 1. The lower ends of the channels 14, 15 are limited, on the side opposite that of the drum 1, by deflecting surfaces or ramps 23, 24 whose extreme edge, such as 25 in FIGS. 4 and 5, extends parallel to the axis 20 of the rotor 19 and over the same length as the latter. This edge 25 can advantageously be wavy (FIG. 6). The arrangement of these ramps 23, 24 is still symmetrical with respect to the vertical plane passing through the axis 20 of the rotor 19 and through the axis of the drum 1, so that the operation of the device is the same, regardless of the direction of rotation of the drum 1. Depending on the direction of inclination of the limit surface 23ʹ, 24ʹ of the ramps 23, 24, the speed of flow of the liquid downstream of these can be increased or decreased.

Bien qu'il soit possible de donner à l'électrolyte un sens d'écoulement identique au sens de rotation du tambour 1, des études expérimentales ont montré qu'il est avantageux, pour avoir un dépôt convenable, de donner à l'électrolyte un sens d'écoulement inverse (voir flèches F et Fʺ à la figure 3) du sens de rotation du tambour 1 (flèche Fʹ), condition qui est réalisée par exemple sur la figure 3. Il s'est avéré également que, contrairement à ce qui a été dit plus haut, il peut être avantageux d'injecter de l'électrolyte dans les canaux à l'aide d'une rampe ou d'ajutages convergents (26, figures 2 et 3), répartis sur la longueur du tambour 1, afin de donner au liquide une vitesse supérieure à la vitesse de déplacement ou défilement de la bande 2 jouant le rôle de cathode.Although it is possible to give the electrolyte a flow direction identical to the direction of rotation of the drum 1, experimental studies have shown that it is advantageous, in order to have a suitable deposit, to give the electrolyte a reverse flow direction (see arrows F and Fʺ in FIG. 3) of the direction of rotation of the drum 1 (arrow Fʹ), a condition which is achieved for example in FIG. 3. It has also been found that, unlike this which has been said above, it may be advantageous to inject electrolyte into the channels using a ramp or converging nozzles (26, FIGS. 2 and 3), distributed over the length of the drum 1 , in order to give the liquid a speed greater than the speed of movement or movement of the strip 2 playing the role of cathode.

Il est évident que la rampe ou les ajutages convergents 26 peuvent être montés du côté gauche du tambour 1 plutôt que du côté droit du tambour comme montré aux figures 2 et 3.It is obvious that the ramp or the converging nozzles 26 can be mounted on the left side of the drum 1 rather than on the right side of the drum as shown in FIGS. 2 and 3.

Enfin, l'expérience a montré aussi que l'on doit, dans certaines conditions qui sont fonctions de la largeur de la bande 2 et de sa vitesse de défilement, faire tourner le rotor 19 dans le sens contraire à celui de l'écoulement du liquide dans les canaux 14, 15.Finally, experience has also shown that it is necessary, under certain conditions which are a function of the width of the strip 2 and of its running speed, to rotate the rotor 19 in the opposite direction to that of the flow of the liquid in channels 14, 15.

Dans l'un et l'autre cas, le rotor 19 intervient pour répartir uniformément l'énergie supplémentaire positive ou négative qu'il faut communiquer à l'électrolyte pour garantir une vitesse relative uniformément répartie en aval du rotor 19, pour satisfaire, suivant la vitesse de défilement de la bande et la densité de courant, aux conditions d'un dépôt de zinc du type mono-orienté compact.In both cases, the rotor 19 intervenes to uniformly distribute the additional positive or negative energy which must be communicated to the electrolyte to guarantee a relative speed uniformly distributed downstream of the rotor 19, to satisfy, according to the tape running speed and the current density, under the conditions of a zinc deposit of the compact mono-oriented type.

Le procédé suivant l'invention consiste donc:
- à obtenir une même densité du courant d'électrolyse en tous points grâce à une alimentation indépendante de chaque anode 5ʹ, 6ʹ en courant électrique, et au réglage de la tension de chaque anode et
- à régler la vitesse relative du fluide par rapport à la bande 2 pour réaliser des structures cristallines mono-orientées compactes.The process according to the invention therefore consists:
to obtain the same density of the electrolysis current at all points by means of an independent supply of each anode 5ʹ, 6ʹ with electric current, and by adjusting the voltage of each anode and
- To adjust the relative speed of the fluid with respect to the strip 2 to produce compact mono-oriented crystal structures.

La vitesse relative du fluide par rapport à la bande 2 peut être modifiée:
- en changeant le débit d'électrolyte dans les passages 14, 15, c'est-à-dire en changeant la vitesse de rota­tion de la pompe 28 (voir figures 2 et 3) amenant l'électrolyte par le conduit 29 et la rampe ou l'aju­tage convergent 26 dans la cellule et/ou
- en changeant la vitesse de défilement de la bande d'acier 2, c'est-à-dire en changeant la vitesse du moteur 30 entraînant en rotation un tambour 31 sur lequel vient s'enrouler la bande d'acier 2 (voir figure 3).The relative speed of the fluid with respect to the strip 2 can be modified:
- by changing the electrolyte flow in the passages 14, 15, that is to say by changing the speed of rotation of the pump 28 (see Figures 2 and 3) bringing the electrolyte through the conduit 29 and the ramp or the nozzle converge 26 in the cell and / or
- by changing the running speed of the steel strip 2, that is to say by changing the speed of the motor 30 driving in rotation a drum 31 on which the steel strip 2 is wound up (see figure 3).

Claims (18)

1. Procédé d'électrozingage d'une bande d'acier (2), dans lequel on fait défiler une bande d'acier (2) jouant le rôle de cathode en face d'une série d'anodes (5, 6), tandis qu'on fait circuler entre la cathode et les anodes (5ʹ, 6ʹ) un flot d'élec­trolyte chargé de zinc, caractérisé en ce qu'on alimente chaque anode (5ʹ,6ʹ), indépendamment des autres anodes, en courant électrique, et en ce qu'on règle la tension de chaque anode pour faire passer une quantité de courant électrique détermin­née à travers chaque anode (5ʹ 6ʹ) pour obtenir, à partir de chacune de ces anodes (5ʹ, 6ʹ), une même densité du courant d'électrolyse en tous points.1. Method for electrogalvanizing a steel strip (2), in which a steel strip (2) is passed, acting as a cathode in front of a series of anodes (5, 6), while a flow of zinc-charged electrolyte is circulated between the cathode and the anodes (5ʹ, 6ʹ), characterized in that each anode (5ʹ, 6ʹ) is supplied with electric current independently of the other anodes, and in that we regulate the voltage of each anode to pass a given quantity of electric current through each anode (5ʹ 6ʹ) to obtain, from each of these anodes (5ʹ, 6ʹ), the same current density electrolysis at all points. 2. Procédé suivant la revendication 1, caractérisé en ce qu'on règle le débit de l'électrolyte circulant entre la bande (2) et les anodes (5ʹ, 6ʹ) de manière à obtenir une vitesse relative déterminée de l'électrolyte par rapport à la bande (2) pour obtenir sur la bande (2) un dépôt de zinc à structure mono-orientée compacte.2. Method according to claim 1, characterized in that the flow rate of the electrolyte circulating between the strip (2) and the anodes (5ʹ, 6ʹ) is adjusted so as to obtain a determined relative speed of the electrolyte relative to to the strip (2) to obtain on the strip (2) a deposit of zinc with a compact mono-oriented structure. 3. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce qu'on règle la vitesse de défilement de la bande (2) en face des anodes (5ʹ, 6ʹ) de manière à obtenir une vitesse relative déterminée de l'électrolyte par rapport à la bande pour obtenir sur la bande un dépôt de zinc à structure mono-orientée compacte.3. Method according to any one of the preceding claims, characterized in that the running speed of the strip (2) opposite the anodes (5ʹ, 6ʹ) so as to obtain a determined relative speed of the electrolyte relative to the strip to obtain on the strip a deposit of zinc with a compact mono-oriented structure . 4. Installation d'électrozingage pour revêtir en continu une bande d'acier (2) d'un dépôt de zinc, et qui comprend un tambour isolant (1) autour duquel passe, en l'entraînant, la bande (2) servant de cathode, tandis qu'en face de la bande (2) et séparées de celle-ci par un flot continu d'électrolyte contenant du zinc, se trouve une série d'anodes (5, 6), placées les unes (5ʹ, 6ʹ) à côté des autres (5ʹ et 6ʹ) et montées à l'extrémité de branches d'un circuit électrique (7, 8) débitant dans chacune d'elles un courant continu, caractérisée en ce que lesdites branches de circuit (7, 8) sont ramifiées en un nombre de branches (17), égal à celui des anodes (5ʹ, 6ʹ), chaque branche (17) contenant un ensemble individuel (18) comprenant chacun un redresseur de courant et un dispositif indépendant de réglage de la tension, permettant d'obtenir que le courant débité dans chaque branche (17) corresponde à une même densité de courant dans chacune des branches comprenant respectivement une anode (5ʹ, 6ʹ) et une portion correspondante de la bande d'acier (2) qui se déplace devant elle.4. Electrogalvanizing installation for continuously coating a steel strip (2) with a deposit of zinc, and which comprises an insulating drum (1) around which passes, by entraining, the strip (2) serving cathode, while opposite the strip (2) and separated from it by a continuous stream of electrolyte containing zinc, is a series of anodes (5, 6), placed one (5ʹ, 6ʹ ) next to the others (5ʹ and 6ʹ) and mounted at the end of branches of an electrical circuit (7, 8) delivering in each of them a direct current, characterized in that said circuit branches (7, 8 ) are branched into a number of branches (17), equal to that of the anodes (5ʹ, 6ʹ), each branch (17) containing an individual assembly (18) each comprising a current rectifier and an independent device for adjusting the voltage , making it possible to obtain that the current delivered in each branch (17) corresponds to the same current density in each of the branches respectively comprising an anode (5ʹ , 6ʹ) and a corresponding portion of the steel strip (2) which moves in front of it. 5. Installation suivant la revendication 4 caractérisée en ce que les anodes (5ʹ, 6ʹ) sont séparées l'une de l'autre par une couche de matière isolante (27).5. Installation according to claim 4 characterized in that the anodes (5ʹ, 6ʹ) are separated from each other by a layer of insulating material (27). 6. Installation suivant la revendication 4, caractérisée en ce que les anodes (5ʹ, 6ʹ) sont réparties autour de la circonférence du tambour (1) et entourées par une enveloppe extérieure (13) en sorte de constituer autour du tambour (1) deux canaux (14, 15) symétriques par rapport à un plan vertical passant par l'axe du tambour (1), ces canaux étant traversés par un électrolyte contenant du zinc, l'alimentation en électrolyte se faisant par une extrémité supérieure de l'un (14) des canaux, et l'évacuation de l'électrolyte usé par l'extrémité de l'autre canal (15).6. Installation according to claim 4, characterized in that the anodes (5ʹ, 6ʹ) are distributed around the circumference of the drum (1) and surrounded by an outer envelope (13) so as to constitute around the drum (1) two channels (14, 15) symmetrical with respect to a vertical plane passing through the axis of the drum (1), these channels being traversed by an electrolyte containing zinc, the supply of electrolyte being carried out by an upper end of one (14) of the channels, and the discharge of the used electrolyte through the end of the other channel (15). 7. Installation suivant la revendication 6, caractérisée en ce qu'en dessous du tambour (1) se trouve, entre les deux extrémités inférieures des deux canaux symétriques (14, 15), un rotor (19) à aubes (22) entraîné par un moteur (21).7. Installation according to claim 6, characterized in that below the drum (1) is located between the two lower ends of the two symmetrical channels (14, 15), a rotor (19) with blades (22) driven by a motor (21). 8. Installation suivant la revendication 7, caractérisée en ce que les extrémités inférieures des canaux (14, 15) sont limitées d'un côté par le tambour (1) et de l'autre côté par des rampes (23, 24).8. Installation according to claim 7, characterized in that the lower ends of the channels (14, 15) are limited on one side by the drum (1) and on the other side by ramps (23, 24). 9. Installation suivant la revendication 8, caractérisée en ce que l'arête limite (25) des rampes (23, 24), située du côté le plus voisin du rotor (19), est ondulée.9. Installation according to claim 8, characterized in that the limit edge (25) of the ramps (23, 24), located on the side closest to the rotor (19), is wavy. 10. Installation suivant la revendication 7, caractérisée en ce que les aubes (22) du rotor (19) sont radiales.10. Installation according to claim 7, characterized in that the blades (22) of the rotor (19) are radial. 11. Installation suivant la revendication 7, caractérisée en ce que les extrémités des aubes (22) se trouvent à même distance du pourtour du tambour (1) que les surfaces des anodes (5ʹ, 6ʹ) orientées vers le tambour (1).11. Installation according to claim 7, characterized in that the ends of the blades (22) are at the same distance from the periphery of the drum (1) as the surfaces of the anodes (5ʹ, 6ʹ) oriented towards the drum (1). 12. Installation suivant la revendication 6, caractérisée en ce que l'alimentation des canaux (14, 15) se fait par injection d'électrolyte dans ces canaux au moyen de rampes ou d'ajutages convergents (26).12. Installation according to claim 6, characterized in that the supply of the channels (14, 15) is by injection of electrolyte in these channels by means of converging ramps or nozzles (26). 13. Installation suivant l'une quelconque des revendications 4 à 12, caractérisée en ce que la bande (2) jouant le rôle de cathode est entraînée dans le même sens que celui de l'écoulement de l'électrolyte le long de la bande (2).13. Installation according to any one of claims 4 to 12, characterized in that the strip (2) playing the role of cathode is driven in the same direction as that of the flow of the electrolyte along the strip ( 2). 14. Installation suivant l'une des revendication 6 à 12, caractérisée en ce que la bande (2) jouant le rôle de cathode est entraînée dans le sens opposé à celui de l'écoulement de l'électrolyte le long de la bande (2).14. Installation according to one of claims 6 to 12, characterized in that the strip (2) playing the role of cathode is driven in the opposite direction to that of the flow of the electrolyte along the strip (2 ). 15. Installation suivant l'une quelconque des revendications 7 à 14, caractérisée en ce que le rotor (19) tourne dans le même sens que le tambour (1).15. Installation according to any one of claims 7 to 14, characterized in that the rotor (19) rotates in the same direction as the drum (1). 16. Installation suivant l'une quelconque des revendications 7 à 14, caractérisée en ce que le rotor (19) tourne en sens opposé à celui du tambour (1).16. Installation according to any one of claims 7 to 14, characterized in that the rotor (19) rotates in the opposite direction to that of the drum (1). 17. Installation suivant l'une quelconque des revendications 4 à 16, caractérisée en ce qu'une pompe (28) à débit variable amène le flot continu d'électrolyte contenant du zinc à passer entre la bande (2) et les anodes (5ʹ, 6ʹ), de manière à obtenir une vitesse relative déterminée de l'électrolyte par rapport à la bande (2).17. Installation according to any one of claims 4 to 16, characterized in that a pump (28) with variable flow causes the continuous flow of electrolyte containing zinc to pass between the strip (2) and the anodes (5ʹ , 6ʹ), so as to obtain a determined relative speed of the electrolyte relative to the strip (2). 18. Installation suivant l'une quelconque des revendications 4 à 16, caractérisée en ce qu'un moteur (30) à vitesse variable entraîne la bande (2), de manière à obtenir une vitesse relative déterminée de l'électrolyte par rapport à la bande (2).18. Installation according to any one of claims 4 to 16, characterized in that a variable speed motor (30) drives the strip (2), so as to obtain a determined relative speed of the electrolyte relative to the band (2).
EP87870098A 1986-07-17 1987-07-13 Process and apparatus for electroplating zinc on a steel strip Expired - Lifetime EP0254703B1 (en)

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LU86520A LU86520A1 (en) 1986-07-17 1986-07-17 PROCESS FOR THE CONTINUOUS ELECTROZINGING OF A STEEL SHEET ELECTROLYTICALLY
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EP0875605A2 (en) * 1997-04-25 1998-11-04 Sms Schloemann-Siemag Aktiengesellschaft Arrangement for the electrogalvanic metal coating of strips
FR2765597A1 (en) * 1997-07-02 1999-01-08 Kvaerner Metals Clecim Installation for the electrolytic plating of metal strip and an anode for such installation
US5944965A (en) * 1992-07-01 1999-08-31 Gould Electronics Inc. Method and apparatus for sequentially metalizing polymeric films and products made thereby

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US4500400A (en) * 1983-10-07 1985-02-19 Kawasaki Steel Corporation Counter flow device for electroplating apparatus

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0425354A1 (en) * 1989-10-27 1991-05-02 Sollac Process and apparatus for electroplating a metallic strip
FR2653787A1 (en) * 1989-10-27 1991-05-03 Lorraine Laminage INSTALLATION AND METHOD FOR ELECTROLYTIC COATING OF A METAL STRIP.
US5188720A (en) * 1989-10-27 1993-02-23 Sollac Installation and process for electrolytic coating of a metal strip
US5944965A (en) * 1992-07-01 1999-08-31 Gould Electronics Inc. Method and apparatus for sequentially metalizing polymeric films and products made thereby
US6224722B1 (en) 1992-07-01 2001-05-01 Gould Electronics Inc. Method and apparatus for sequentially metalizing polymeric films and products made thereby
EP0867529A1 (en) * 1997-03-26 1998-09-30 Gould Electronics Inc. A method and apparatus for sequentially metalizing polymeric films and products made thereby
EP0875605A2 (en) * 1997-04-25 1998-11-04 Sms Schloemann-Siemag Aktiengesellschaft Arrangement for the electrogalvanic metal coating of strips
EP0875605A3 (en) * 1997-04-25 1998-12-09 Sms Schloemann-Siemag Aktiengesellschaft Arrangement for the electrogalvanic metal coating of strips
FR2765597A1 (en) * 1997-07-02 1999-01-08 Kvaerner Metals Clecim Installation for the electrolytic plating of metal strip and an anode for such installation
US6024846A (en) * 1997-07-02 2000-02-15 Kvaerner Metals Clecim Installation for electrolytic coating of metallic bands and anode for such an installation

Also Published As

Publication number Publication date
ATE67529T1 (en) 1991-10-15
EP0254703B1 (en) 1991-09-18
DE3773075D1 (en) 1991-10-24
LU86520A1 (en) 1988-02-02
ES2026947T3 (en) 1992-05-16
GR3003356T3 (en) 1993-02-17

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