Method and means for continuously contact-coating one side only of a ferrous base metal strip with a molten coating metal

The invention relates to an installation for the metallic coating of the strips, on one side, with a liquid metal contained in a tank ·, allowing a uniformization of the deposited material and an adequate protection of the uncoated part.

There are known installations of metallic coating of the strips on one side and that move continuously, formed of a basin, in which there is a melting of the material to be deposited. The metal strip is passed between guide rollers, to be directed to the level of the metal bath with which it comes into contact. Due to the phenomenon of audibility that arises between the metal bands subjected to the coating operation and the surface of the metal bath, a meniscus is formed, which allows a continuous contact between the moving metal band and the surface of the molten metal, which is trained to cover the metal band face. subjected to roofing operation.

These installations have the disadvantage, on the one hand, that they cannot make a uniform metal coating, and 'on the other hand, iiu..can achieve the protection of the uncoated metal face against its oxidation' â-depuhertior d'e metal.

72 394 . ......... '' 'J_fThere are also known installations for coating only one part of the metal strips, using a liquid metal in spray form. The liquid metal, from a container, is directed to the sprayers in a closed chamber. Below the sprayed metal jet is directed a metal strip, which is covered by the sprayed metal. After the tape has been covered, it is still passed between rollers, in order to make the layer of material deposited.

These plants have the disadvantage that they have low productivity.

¹⁵ Also, there are known coating installations, formed by some rollers, which direct the metal strip through a bath with itopirt metal, after which the respective strip is directed towards an aggregate of ²⁰ Heating. After the tape has the proper temperature, it is directed again to the molten metal bath and then to: a hood above the metal bath.₂₅ melted. In the .respect hood the band is passed through some reels, after which it is given, already towards; another bath with molten metal, for example, zinc. In the metal bath, molten is kept by some rollers, in order to steal the respective coating, after the tape, · ',,. ·, · LEI PRICE 14.89 with a certain layer of zinc deposited on both sides, (leaves the metal bath.

These installations have the disadvantage that they cannot make metal coatings on one side of the strips.

The installation according to the invention removes the aforementioned disadvantages, in that, for the purpose of making a metal coating, on one side of the strip, a strip which, on the uncoated surface, must remain free of splashes of metal deposited or oxidized, is formed, in the first embodiment, from a basin, which contains a metallic melt whose surface comes in contact only with a face of the metal strip subjected to the coating operation, operation that takes place inside a hood, (provided with some connections, to introduce a protective atmosphere both inside the respective hood and in a space created between the rollers of a sealing device, this device is inside the hood , with a view to directing the metal strip to other rollers, in order to come into contact with the surface of the liquid coating metal, and subsequently, the metal strip, covered on one side with liquid metal, it is directed to a device for uniformizing the deposited layer, after this -band has left the coating installation, an installation which, in another constructive variant, is composed of the same component elements as the coating installation from the first embodiment, at its own - additionally provided a cooling room, on which some heat exchangers were fixed to cool the gases and to be directed to the surfaces of the metal strip so that this tape had a low temperature, when it came into contact with the surrounding atmosphere, after leaving the roofing installation, installation in another embodiment, has the cooling chamber provided with an outlet mouth located below the level of a cooling fluid, located in a tank, and for the evacuation of the resulting gases there was provided a tubing, which has a flap and connections for introducing the protective atmosphere inside the coating plant, this coating installation was also provided with electrochemical cleaning devices of the metal strip, formed from a roller in contact with both a current source and the metal strip subjected to the cleaning operation, a strip which is also in contact with an Acadian cleaning environment, connected to the power source.

Further examples of embodiments of the invention are given below, and in connection with FIG. 1 ... 19, which represents:

FIG. 1, section in vertical plane through the tank of the installation and schematic representation4 that of the component elements of that pipeline from the first embodiment;

FIG. 2, cross section according to plane I-I, according to fig. 1, through the installation;

FIG. 3, section, on a larger scale, by the detail A of fig. i;

FIG. 4, cross-section, on an enlarged scale, by the detail A of fig. 3, which illustrates the type of meniscus that may occur if used (aluminum as molten metal coating;

FIG. 5, longitudinal section through basin and schematic representation of the component elements of the installation, in another embodiment;

FIG. 6, the partial cross section through the sealing block and the third roller, shown in fig. 5 ;

FIG. 7, a cross-section through the basin and a schematic representation of the component elements, illustrating the coating installation shown in fig. 1 or 5, without using the sealing block;

FIG. 8, cross-section through the basin and schematic representation of the component elements of the installation, in another embodiment;

- fig, 9, Cross section and schematic representation of the device for cleaning the metal strip;

- fig, 10, cross-section and schematic representation of the component elements of the cleaning device, in another constructive variant;

FIG. 11, schematic representation of the metal strip cleaning device, in another embodiment;

FIG. 12, cross section through the installation, in> another embodiment;

FIG. 13, cross section through the installation and through the cooling chamber, in another embodiment;

FIG. 14, section (transverse through the installation and through the cooling chamber, in another embodiment;

~~ fig. 15, cross section through the installation and concerning the cooling chamber, in another embodiment;

FIG. 16, vertical section through the roofing installation, in another constructive variant, which the entire coating and finishing technological operation is carried out in a protective environment;

FIG. 17, vertical section through the tank and schematic presentation of the component elements of the installation of fig. 8, in which jets are used, to uniformize the adhered metal on the surface of the strip; .

FIG. 18, section through the roofing installation, to which a uniformization device is used, in another embodiment;

FIG. 19, partial view, in horizontal plane, of the installation of fig. 18.

The installation according to the invention, shown in FIG. 1, requires the use of a conventional strip 1, which was previously prepared for the technological coating process. For example, tape 1 can be cleaned in a non-oxidizing preheater, chilled and cooled in a protective atmosphere, at high temperatures. The precise nature of the preparation steps of the tape 1 does not impose any restrictions, as long as the tape 1 is at a correct temperature and its surfaces are cleaned with an acid solution and are not oxidized.

The coating installation, as shown in fig. 1, comprises a covering tub 2, which contains a molten metal bath 3. By this bath 3, more precisely, in contact with this bath 3, the iron-based metal strip 1 is passed, which is to be covered on one from its faces with the metal cover 3. The coating process is carried out under a hood B, provided with an extension a, which enters the metal bath 3 and with another extension b, where the coating layer is uniformized. Connections 4 and 5 for the introduction of the protective gas are fixed on the hood B.

The hood B consists of a front wall 6, a rear wall 7, some side walls 8 and a top cover 9. As shown in FIG. 1 and 2, the front wall 6, the rear wall 7 and the two side walls 8 extend downwards and into the molten metal bath, forming the extension of a. The front wall 6 has a U-shaped slot c to allow the exit of the strip 1 inside the hood B, after this strip 1 has passed through a sealing device C and between guide rollers 10 and 11. The slot The output will have such a width as to allow the passage of a larger range of bands 1 as a width, bands 1 formed of metal based on iron, should be only one-sided.

The metal strip 1 passes through the sealing device C, formed by some rollers 12, 13, 14 and 15. The rollers 13 and 15 are in contact with some supports 16, between which there is a space d, in connection with the connection 4. From the sealing device C, the tape 1 passes to the guide wheel 10 and, from here 'to the roll 11 »located above the liquid metal 3, so as not to loosen a contact between the face of the strip 1 and a surface of the molten metal 3. From the roll 11 , lane 1. passes through the outlet slot c. to another roll 17 and, from here ·, changes its direction, to exit the molten metal bath 3, trolling through a uniforming device of the deposited metal layer D. The rolls 10, 11 and 17 are supported in a manner - suitable by some conventional means, not figured. / <

On the front wall 6 of the hood B. A housing 18 is fixed, in which a graphite block 19 is inserted, which has the function of closing at the top most of the exit slot c. The graphite block 19 is free to open. move up or down inside the housing 18, remaining permanently with the top or underside of the metal strip 1.

It is very important that a protective atmosphere is provided inside the hood · B, so that the surfaces of the strips 1 remain clean and without oxidation before being coated. For this purpose, the hood B was provided with the inlet nozzle 5, through which a protective, non-oxidizing gas is introduced inside the hood B. Any suitable protective gas, non-oxidizing, suitable, such as, nitrogen, inert gas or other similar gases , can be used. The non-oxidizing atmosphere at the bottom of the hood B must be maintained at a slightly higher pressure than the surrounding atmospheric pressure on the outside of the hood B, which is oxidizing and must not penetrate inside this hood B through slot c and through spaces f and g, according to FIG. 2, closed by the sealing graphite block 19. Similarly, it is preferable to provide the inlet connection 4 for the non-oxidizing atmosphere between the pair of rollers 12—13 and 14—15 of the sealing device C. It is preferable that the non-oxidizing atmosphere in space d be at a slightly higher pressure. than the pressure inside the hood E and higher than the pressure inside the extension b. By this, the non-oxidizing atmosphere inside the extension b cannot be contaminated, even during the shutdown of the installation. Because the pressure of the non-oxidizing atmosphere inside the space d is higher than the pressure of the surrounding atmosphere, it will prevent the contamination of the atmosphere inside the extension b. Finally »the covered part of the strip 1 will be finished with the uniformization device D, formed by a nozzle 20 and a reel 21. The nozzle 20 may move vertically, taking several positions, denoted by a dashed line h, to achieve a uniform layer pc a surface at the hen 1, due to a pressure of a fluid coming out through the nozzle 20.

During operation, the metal strip 1 is inserted between the rollers 12-13,14-15, 10, 11 and 17 and moves in one direction j. On the surface of the molten metal bath 3 a lift can be formed, which will determine its contact with the egg face to the metal strips 1, surface tension and the wetting characteristics of the coating metal will form. which will keep you continuously and will cover the respective surface. Due to this k-shirt, a continuous counting of only one face can be made on the tape 1, without the need to steal the tape 1 in the metal bath 3. After the tape 1 leaves the roll 17, it will have an uncoated face. 1 and a face i, covered with a certain coating.

In order to render the coverage phenomenon more clearly, the thickness of the strip 1, the distance between the rollers 11 and 17 from the surface of the metal bath 3 and the height of the menu 'k have been oversized. The distance between the surface and the strip 1, to be covered, compared to the surface as the metal bath 3, will allow the formation and maintenance of the covering meniscus k, to some extent, depending on the coating metal used, by the surface tension, as well as by the wetting characteristics of its bond. Good results were obtained with the majority of the coating metals, when this distance was maintained at about 17.3 mm.

It is preferable that the roller 11 be placed slightly higher than the surface of the molten metal bath 3 and than the roller 17. And in this case, the height difference was oversized, for clearances. A difference in actual height from about 3.17 mm to about 6.35 mm is preferable. The purpose of this spherical height difference to ensure this roll against touching or depositing the molten metal of the coating 3 on the roll 11, is disposed at the bottom of the hood B and is therefore not visible to the operator performing the coating operation.

The nozzle 20 may be located below or even on the center line of the roll 17. In the tub where the center line of the roll 17 is below, the jet nozzle 20 may be positioned depending on the diameter of the roll 17 and the speed of the strip 1. It is important so that this nozzle 20 does not direct an atmosphere contaminated by the slot as the hood B or which can destroy the meniscus k. The jet nozzle 20 may be disposed above the roller 17, as shown by dashed lines h. In order to ensure a correct finishing jet, it is important that the cross section of the strip 1 remains rectangular.

For this purpose, it is preferable that the positioning roller 21 be provided on the opposite side with a dia., For directing the fluid jet, similar to the nozzle 20. There have also been fixed holes in the vessel 1, in connection with a 'eondudțdr 22. .between .meijgfnile of band 1 and anetals, liquid' 3; j is formed uh menise m towards the inside of the surface, ea liquid metal .Ș;_;so / as. .is shown in FIG. 4:

. Insatiation, according to the invention ^ in another reddish-reddish; shown in · fig; · 5, it is made up of dih 'iseofeleași' dletaertte '^ cdm8 speakers as the installation of the first embodiment, in particular that a roll 23 was placed outside the hood B, between rolls 11 and 17. Roll 23 will be provided with a suitable support, not shown, and is so arranged as to deflect that part of the strip 1 which lies between the rollers 11 and 17 slightly towards the metal bath 3. This arrangement will allow rollers 11 and 17 to be slightly raised from the surface of the metal bath 3, to prevent the deposition of molten metal on these rolls 11 and

17. The roller 23 will be located at a distance slightly smaller than the width of the strip 1 to be drawn, in order to cover it with the covering metal 3. Oa and in the case of the installation of the first construction variant, represented in fig. 1 ... 3, the installation in this embodiment has a sealing system C, located at the entrance of the metal strip 1, also consisting of two pairs of sealing rollers 12-13, 14-15. The four walls of the hood B, respectively the front wall · 6, [the rear wall 7 and the two side walls 8, are inserted with the lower part in the metal bath 3. In order to maintain a constant temperature in the molten metal roof covering 3 is inserted. an electrical resistor 24, supplied by the conductor 22, which also has the role of electrode.

in FIG. 7 is shown a section similar to the section in fig. 2 and can be considered as being made by a transverse plane near the front wall 7 of the hood B. In contrast to the section in fig. 2, the casing 18 and the graphite block 19 are no longer seen in the section in fig. 7. The tri c, formed in the front wall 6, was lowered to a position just above the strip 1, in order to reduce the hole through which the web 1 leaves the hood B. In the examples in fig. 1 and 5, the graphite block 19, which has the role of gasket, and the housing 18 can be removed. The penetration of the oxidizing atmosphere through the slot c can be stopped, due to maintaining a high urea pressure of the non-oxidizing atmosphere inside the hood B.

The sealing system E, in another constructive variant, according to fig. 6 is formed by a block 25, at the end of which a roller 26 is inserted.

The coating installation, in another constructive variant, shown in fig. 8, is also formed of a tank 2, which contains a certain amount of metal melts 3. ..- This installation is provided with a sling F, placed above the surface of the liquid metal 3. - The hood-F can be integrated into the slopes beyond the hood; Does it have any idea of ​​being connected to this through tight joints? ·. . r '

The hood F, at the side of the entrance, is provided with a sealing device, sealed with pairs of sealing rollers 2728 and 29-30. For the introduction of the atmosphere (non-oxidizing in the space of the sealing device and inside the hood F, there are provided connections 31, fixed in a lid 32 of the hood F. The hood F of jnai was provided with walls 33, 34 and 35, which penetrate into the liquid metal 3. The metal strip 1 passes between the pairs of rollers 27-28 and 29-30 of the sealing device towards a drive roll 36, to be directed to another roll 37, to bring the surface to this part 1, to be covered. , near the surface of it of the molten metal bath 3. The roller 37 then directs the strip 1, coated on one side i, outside the molten metal bath 3 and, through an outlet port n of the lid 32, the strip 1 leave the installation.

The hood F, as described, was provided with the inlet connection 31, through which a non-oxidizing atmosphere is introduced, an atmosphere which is maintained inside the hood F at a pressure slightly higher than the atmospheric pressure, which contains oxygen, atmospheric pressure that will not be able to enter through outlet no. The sealing device and the respective connection 31 can serve for the same purpose the sealing device C, together with egg dose 4 from the installation of the first embodiment. in the case of the installation shown in fig. 8, inside the hood F was introduced and the nozzle 20, to direct a flow of fluid over the surface. of the strip 1. The jet leaving the nozzle 20 pies was made of the same non-oxidized gases as the gases inside the hood F.

During the operation, unlike the installation of the first embodiment, the coating and uniformization operations are carried out inside the hood F and in its protective, non-oxidizing atmosphere. The metal strip 1, inserted in the installation, as shown in Fig. 8, is moved in the direction of the arrow j and forms on the surface of the molten metal bath a small box, the cane will have a result forming a meniscus o, .of which the surface take tape 1. comes into contact with the surface of the molten metal bath 3, it will be covered by continuous contact with the liquid metal 3 when it passes under the roll 37. The supporting elements, not shown, inside the hood F for the rollers 36 and 37 and for the nozzle. they are of known construction. When the metal strip 1 passes, towards the exit port, it will be covered on the one side and not covered on the other side L. The covered part will be finished by means of the jet made by the nozzle 20, it can be flossed in any position, only provided that it does not destroy the meniscus o, formed on the surface of the molten metal bath 3. If the technological process requires the nozzle 20 to be disposed above the roller 37, at a certain distance, as this affects the transverse shape of the strip 1, then an additional roller, identical to the roller 21, described in the first embodiment, may be provided for to maintain in cross-section the cross-section of tape 1 throughout the finishing operation.

In the case of this embodiment as well as the embodiments described below, the metal strip 1 will come into contact with the atmosphere of the environment, while it is still at a sufficiently high temperature, giving rise to the formation of a film. visible of the oxide on the uncoated part 1 thereof. For small exposure times, the visible oxide film will be in the form of layers or zinc oxide films, the film adjacent to the metal base being, first of all, the iron oxide, FeO, followed by a tetraoxide film. iron, Fe₃O «, and finally a layer of iron trioxide. If the temperature of the band 1, when exposed to an oxidizing atmosphere, is less than about 570 ° C, the iron oxide layer, FeO, will not form, this temperature is specific to the case when the molten metal of the coating 3 is zinc. When the molten metal of coating 3 is aluminum, the temperature of the strip will normally exceed 570 ° C, when a layer of flue-FeO oxide will form.

The visible oxide coating can be removed by means of an acidic cleaning process, as mentioned above. Through this cleaning process, in the arid solution, as opposed to the original, only the purely chemical dissolution -a film 'of oxide formed is sought. Oxide films dissolve at different speeds. Dissolution of iron tetraoxide film - Fe₃A'. - it is made at a controlled speed, because this oxide dissolves very slowly. Porous zinc oxide films can be removed by penetrating the aidb solution and directly attacking the metal base of the band 1. The oxide removal rate can be increased either by changing the rate of the chemical reaction, by raising the temperature of the acid solution, when the rate of increase is increased. chemical reaction, either by increasing the acid concentration of the cleaning solution. Also, the removal rate of the oxide can be achieved by means of an electric current. This increases the dissolution of the metal base and the local surface, by shaking, as a urine for hydrogen generation.

Cleaning with an acid solution of a metal strip based on iron 1, covered on one side i, offers a unique problem;

in that it is desirable to remove 2 - c. 12351, thesis the oxide film on the uncoated part 1 of this strip 1, simultaneously with the minimal damage of the coated part i.

'Acidic solution cleaning involves a large number of interdependent variables, which almost always lead to an infinite number of combinations of these variables. For cleaning with acid solution on one side of the metal strip 1, linear relationships between these variables will be established.

The basic variables of the cleaning process in acid solution include the acid used, the acid concentration, the acid temperature, the elotrode-band distance, the holding time of the bath in the bath and the density of the current used. In order to minimize the damage to the coated part and the strip 1, a dilute acid solution is preferred, generally taking a volume of 1% commercial acid or less. The type of acid used will be determined based on its effectiveness, cost and availability, pollution control requirements and ventilation possibilities. Sulfuric, phosphoric, hydrochloric acid and nitric acid may be used for this purpose. Sulfuric acid and phosphoric acid are somewhat more active, and sulfuric acid is preferred not only because of its effectiveness, but also because of its easier procurement possibilities.

The temperature of the acid solution will be kept at a low value, below about 38 ° C, if it is due to reduce the staining or corrosion of the metal covered part · or, better, of the metal strip I. The distance between the electrode and the band 1 will be as small as possible, to increase the efficiency of the dry cleaning process. However, the distance between the electrode and the metal tape will be determined so as to avoid contact with the electrode band, the time of i.merSession of the tape 1 in the cleaning bath will also be reduced, so that the time required for removing the film from the oxide to be as small as possible. From a practical point of view, the banding time of the band will be determined according to the size of the tank with arid solution and the speed of action on the band 1. For the practical realization of the cleaning process, a minimum current density was chosen at the electrode and of 31.3, 62.6 A / cm².

Increasing the current density above the set value will directly lead only to unnecessary current consumption.

The cleaning device G, shown in fig. 9, is formed by a pan 38, which contains a dilute arid solution 39. The metal band ........ 1, with the face covered and the face uncoated 1, is directed around a roller 40 , supported inside the arid solution bath 39, by means of a conventional report, not shown. A block 41, of a metal to be consumed during the cleaning operation, for example, of zinc, is disposed in the propeller As the uncoated part of the metal strip 1 and is held in this position, by means of a suitable support, not shown. The consumable metal block 41 is electrically connected to the metal band 1, via a conductor 42, directly connected to the roller 40. The rate of attack of the metal band, although not increased, the rapid generation of hydrogen on the uncoated side 1 of the metal band 1 helps to agitate the oxide on this side 1. Hydrogen is also generated in the consumable metal block 41 and increases, to help stir the oxide from the uncoated side 1. The consumable metal block 41 may also be made of magnesium or aluminum.

For the practical case, both 0.5% sulfuric acid, 0.5% sulfuric acid and rhyde were used to form the arid solution in bath 39 and this bath 39 was maintained at a temperature of 3.9 ° C. Tape 1 was coated on Part I with zinc and had a zinc oxide coating on the face. 1, oxide strip formed as a result of the exit of the strip 1 from a protective atmosphere inside the air treatment words, at a temperature of the strip of about 480 ° C, the consumable medial block 41, of zinc, was used and maintained at a distance of about 3.2 mm from the metal strip 1 or, better said, from the shaft and onto it. The oxide layer on face 1 was removed in about 3 s with no obvious scratches on the other side and zinc coated.

The cleaning device H, in another embodiment, represented in fig. 10, it is also composed of a sheet 38, which contains a diluted arid solution bath 39. The band 1 is determined to pass around an undamaged roller 43 and next to an electrode 44, which is disposed near the uncoated part 1 of the band 1. The electrode 44 and the band 1, between the roller 43, are connected to a current source 45, by means of the electric conductors 46 and 47.

It has been established that - instead of connecting the conductor 47 from the power source 45 and to the outlet 43, the pipe requires a slip contact. It can directly use the melted coating bath 3, ₍to transmit the electric current to the metal strip 1, in order to eliminate the danger of deteriorating its surface, as shown in fig. 1. In this box, the electric conductor 22, from the power source

-15, may be connected to the vessel 2 with the covering metal 3, when this vessel 2 is made of metal. Also, the conductor 22, as shown in FIG. 5, it can be connected to the electrode 24 inserted in the bath 3.

The device H, of the second embodiment, according to fig. 10, has more efficiency than the device shown in fig. 9. The solution of the iron ion, located below the oxide layer, is accelerated due to the presence of hydrogen which contributes to the stirring of the oxide on the metal band 1, the current source 45 may be an alternating current source or a current source. continuously, although the alternating current source is preferred, due to the pulsations of the current they have the role of increasing the speed of the cleaning process in acid solution. Electrode 44 may be of any suitable material, material that is conductive and non-attacking or, better said, does not seem to be attacked by the dilute acid solution inside the vessel 38. Stainless steel has the best qualities. Other materials, such as platinum or lead, can also be used to make the electrode 44.

In a practical embodiment, the acid solution bath 39 was formed from 0.5¾ sulfuric acid, maintained at a temperature of about 32 ° C. The current source 45 used was a DC generator, which generated a current of about 110 A, and the band 1 constituted the cathode. The electrode 44, the anode, was made of stainless steel. The metal strip 1 had an oxide film on the part 1, formed at the exit of the strip 1 from the non-oxidizing protective atmosphere of the coating device in the air, at a strip temperature of about 480 ° C. The oxide film was removed in less than 6 s, with rapid hydrogen deposition, both on electrode 44 and on surface 1 of strip 1. There was no staining of the zinc coating layer on the coated side and the strip 1, for immersion times in the cleaning bath 39 less than 4 s. Traces of staining and attacking the zinc coating layer appeared. , for 6 s immersion times. Stainless steel electrode 44 was disposed at a distance of approx.

12.7 mm from part 1 of strip 1 not covered.

In another embodiment, the dilute acid solution bath 39 contained 0.5% sulfuric acid, maintained at about 27 ° C, and the electrode 44 was again made of stainless steel. The strip 1 was coated with zinc on the i side and an oxide film on the strip 1, formed due to the exit of the strip 1 towards the protective atmosphere inside the device 'in the surrounding atmosphere, at a temperature of the strip 1 of about 480 ° C. As a current source 45, an AC source was used, which generated an alternating current of approximately 9 A. Electrode 44 was maintained approximately at a distance of 25.4 mm from the uncoated surface 1 of the band 1. In these conditions, the oxide film was removed in about 2 s. No deletion or staining of the zinc coating layer on the coated side of the strip 1 was observed.

The coating device I, in another constructive variant, according to ig. 11 is formed by a roller 48, over which the metal strip passes 1. Instead of a bath of dilute acid solution a sponge 49 is used, soaked with dilute arid solution. The sponge 49 is fixed to a support 50, which can be made of stainless steel or other suitable material and which is not attacked or damaged by the dilute acid solution used. The sponge 49 and its bracket 50 are connected to a power source 51, via a conductor 52. The band 1 is also connected to the power source 51, via an electrical conductor 53 and the roller 48. The power source 51 it can be either an AC power source or a DC power source. In the support 50 of the sponge 49 there is provided an inlet connection 54 which can be performed soaking the sponge 49 with the dilute acid solution. Care must be taken, in this embodiment, for a replacement of the sponge 49 to be done at the optimum time, as a result of the wear of its surface or as a result of the accumulation of oxide particles soaked in it and which cause the scratch of the strip 1.

All cleaning procedures with diluted acid solutions, described above, must be followed by known wash and drying steps, suitable to limit the attack of the acid solution on both sides of the strip 1. Suitable dilute acids, other than those used in the aforementioned examples , can be used, and the selection of the preferred dilute acid depends on the particularities of the process and the possibilities. The diluted acid used may normally include additives, such as different inhibitors, antifoam agents and other known agents.

The acid cleaning, washing and drying steps should be eliminated if the metal strip 1, coated on one side, is maintained in a protective, non-oxidizing atmosphere, until it reaches a temperature, low enough temperature, to. prevent the formation of a visible oxide film on its uncoated side 1.. ,;

The installation, according to the invention, in another embodiment, shown in fig. 12, is composed of the same component elements as the installations of the first construction variants, to which was provided, in addition, a cooling chamber 55, fixed on the lid 32 of the hood F, near the outlet orifice n. The cooling chamber 55 is provided with an outlet port p and is of such length that during the time that the strip 1 passes through the interior of this chamber 55, until the exit p, it will be cooled to a temperature of about 148 ° C, respectively, at the temperature at which no visible oxide layer will be produced on the part I of the strip 1. The cooling chamber 55 will be filled with a non-oxidized atmosphere, which will be introduced through the outlet hole n of the hood F. If necessary, for the introduction of a non-oxidizing atmosphere inside the cooling chamber 55, an inlet connection 56 is provided. A portion of the lid 32, below the cooling chamber 55, which includes the outlet port n can be removed. Except for keeping the tape 1 coated in a protective atmosphere, until it has been cooled sufficiently, to prevent the formation of the visible oxide film on the uncoated face 1, the operation of this constructive variant is identical to that shown in FIG. 8.

The length of the cooling chamber 55, necessary to maintain the tape 1 covered in a protective atmosphere, until it reaches a temperature at which the visible oxide film will not form on its uncoated face 1, can be reduced by providing a means for increasing the speed of the coating. band cooling 1.

In order to increase the time that the tape 1 passes through the interior of the chamber 55, rollers 57 and 58 have been provided, among which the metallic tape 1 passes. These rolls 57 and 58 cause a reduction of its temperature, thus allowing a reduction of the length of the cooling chamber 55. Ga and in the preceding case, the portion of the lid 32, which is adjacent to the cooling chamber 55 and which includes the hole n, can be removed.

The installation according to the invention, shown in fig. 14. 'consists of the same component elements as the installation in fig. 12, to which was added, in addition, a connection 59, through which a suitable protective atmosphere can be introduced inside the cooling chamber 55 if this protective atmosphere 'is required.

On the Vertical walls of the wheelhouse * 'ă'-not provided - its holes,⁵ in connection with the ctl My pipelines 60 and some changes by the eâlddra^;The 6th gift incorporates the results of the ice / similar. Protective atmosphere, cool. In the heat exchangers it is reintroduced into the cooling chamber 55, by means of nozzles 62, which determine the pressure direction of this protective atmosphere directly on the metal band 1. The provision of two diametrically opposed jets will ensure the configuration of the cross section of the band 1. The heat exchangers 61 will allow to shorten the height of the cooling chamber 55, compared to the height of the chamber 55, shown in fig. 12, because the cooling of the band, in this case, will become much more intense.

The installation, according to the invention, in another embodiment, shown in FIG. 15, each consisting of. the same elements as the installation in fig. 14, with the exception that, instead of the cooling chamber 55, a hood 63 is provided, inside which is a roller 64 over which passes the metal strip 1, to be directed to an outlet mouth t. Inside the hood 63, on its output branch, a stop 65 is provided, which has a passage opening u.

The outlet mouth t is located below the level of a cooling medium 66 for example water, located in a basin 67. Inside the basin 67 there is another guide roller 68, Inside the hood 63, the metal strip passes through the roller. 64 and exits the hood 63 directly in the cooling medium 66. The strip 1 is guided through the inside of the cooling medium and is evacuated outside it by means of the roller 68. Near the outlet mouth t, the hood 63 is connected to the outlet pipe 69, provided with a shut-off valve 70. By means of connections 71 and a diaphragm 72, which constitutes a graduated nozzle, the protective atmosphere can be introduced inside the hood. 63 and the discharge of water vapor, resulting in the immersion of the strip 1 in the cooling environment 66. The stop 65 has the role of limiting, as far as possible, the penetration of the water vapor in the hood 63, the non-oxidized, protective atmosphere, inside the hood 63 comes from the hood F, through the hole n.

In all the embodiments, shown in fig. 12 ... 14, the protective atmosphere inside the cooling chamber 33 must be maintained at a sufficient pressure to prevent the oxidizing atmosphere from entering the outside environment.

The installation, according to the invention, in another embodiment, according to fig. 16, as opposed to -Installations from the other streams of art, is. provided with guide rollers 73, and -74, to increase the contact between the strip 1 and the surface of the metal bath 3.

j, Duza 20. is <a3amțatâeî in rihferiQrPl - 'hotei · Fi) dar.-de. aşnmAÎ "TD_?_îhri.ț <6 <.. ny;, 4fecte'iorma, ®ieni ^ şulțyi^; depeaducere- & a, u · o 'dutâp ^ fi ^ ațfe.'țH ^ / ifVPpe.văIî to maintain the surface of the metal strip 1 in proper position.

The operation of the installation, presented in this embodiment, is identical to that of the embodiment shown in fig. 5, and panda 1 will be provided with a covered part and a non-covered face 1. The installation in this embodiment differs from the coating installation in fig. 5, first of all, by the fact that both the coating operation and the uniformization operation of the layer deposited with the aid of a fluid jet were carried out inside the hood F and in its protective atmosphere, thus elimi nating the need for the building block. seal 19, provided at the installation shown in fig. 5. The other side covered with the strip 1 may pass through the outlet n in the surrounding atmosphere, after the strip 1 will be subjected to an adequate cleaning with acidic solution, washed and dried, steps similar to those described above.

. in relation to the concrete working conditions, the roller 74 can be removed. In this case, the installation will be similar to the one shown in fig. 1, but with the distinction that both the coating stage and the finishing stage are executed inside the same F hood.

The installation, according to the invention, in another embodiment, according to fig. 17, is provided, in addition, to the installation in fig. 8, with a hole v, so dimensioned, so that a nozzle 75 can be inserted therein, which has a^!n end k is located inside the hood F, and another end x is outside the hood F. The hole v may be provided with a closing flap 76, the pipe stays on the top of the nozzle 75, when this nozzle 75 is placed inside hood F. When the nozzle 75 is withdrawn, the flap 76 closes the v-hole, to prevent the oxidizing atmosphere from entering this v-hole. The v-hole may be provided with a sealing gasket, not configured, or any other sealing means, to prevent contamination of the protective atmosphere inside the hood F by the surrounding oxidizing atmosphere, which may pass through the v-hole and on the outside. near the nozzle 75. If the hole v has dimensions very close to the peripheral dimensions of the nozzle 75, such sealing means can be avoided, by performing an overpressure inside the hood FV, This modification to the installation of fig. 17 can be applied to any of the embodiments described above, which have the nozzle 20 disposed on the back of the hood F. This arrangement greatly facilitates the periodic cleaning operation._t the respective nozzles, '20 and '75, which one can; ν_>()· ..,. Ί je ····. · F! - ί 'V¹⁸ deposit sprayed metal on the front and the strip 1.

The installation, in another embodiment, according to fig. 18 and 19, is composed of the same component elements, as the coating installation shown in fig. 8, in particular that, near the orifice n, on the cover 32, there are fixed side walls 77, joined by a single front wall 78, to form an open space y, in which it penetrates, at the bottom, the end of the nozzle 75 to achieve, by means of a suitable jet, a uniformization of the metal layer deposited on the surface and of the metal strip 1, for this strip 1 to come into contact with the surrounding atmosphere. Any drop of metal or any formed metal stain will be energetically blown from the uncoated side of the metal strip 1. Where the environmental conditions differ, a roof can be arranged transversely on the sides of the side walls 77. Such a roof will be provided with a slot through which tape 1 can move. The roof or top cover will eliminate any unwanted drive currents that can be created or can be created by the finishing operation. The wall system 77 and 78 must create an opening, on the same side of the uncoated face 1 of the strip 1, to allow the removal of the drops or stains of the metal covering on this uncoated face 1 of the tape 1.

In all the coating facilities described above, the temperature of the metal bath 3 will depend on the coating metal used. The bath must be maintained at a sufficient temperature to ensure that the coating metal will be and will remain molten throughout the finishing operation, the operation performed by. the fluid jet directed through the nozzle 20 or 75, in the case of known processes, of immersion coating, whereby the strip to be coated on both sides is immersed in the bath, and in the case of coating processes on one side of a metal strip. according to the present invention, it does not depend on the metal strip used, 'to print the molten metal bath of the coating a significant amount of heat. Bath temperature, in. practically, it will be the same, both in the case of good coverage on one side, but in the case of coatings on both sides and it will be kept, as far as possible, constant, in order to minimize the formation of slag. . · 'In all the examples described above, and in particular in the case of those using the nrenise o or k, it must be maintained;^!Constantly an adequate level of the bath, for this purpose, a pneumatic displacement chamber or a pneumatic displacement system can be used, for precise adjustment of the level of the Bath, the system itself is known.

OS can use; also, a means for aultimate control of the bath level.

The irietalic coating bath 3 can be heated by any cifUrcised cooling system, including the use of electric rZzlstlVe electrodes. induction heating ', immersion of heating tubes and other similar processes. The volume of the melted metal bath can be much smaller as it is used in typical immersion coating processes on both sides. Because, in accordance with the present invention, the band-bath contact 3 is much lower, the rate of dissolution of the material of the band 1, in comparison with the molten metal flow required to add the bath, will be such that the bath will laugh. the iron is saturated and the slag formation will be eliminated or diminished. This, in turn, will lead to a flawless coating layer. For this reason, it is preferable that she and the pile 2 with the molten metal of the cover 3 be lined with a suitable ceramic material.

The tape will be sufficiently high to allow proper adhesion of the molten metal onto it, but at the same time, the temperature of the tape should not be so high that an excess alloy made between the base metal appears. and the metal that acts as a coating.

In all cases, a protective atmosphere should be maintained in the lower part of the hotel B and F. Any suitable heoxidizing atmosphere, including a ^ δΐύΐ Saif rin inert gas, may be used in this step. The non-oxidizing atmosphere inside the hotel B must be sufficient pressure to deflate & feel the taste of the rust and irritate the surface, through the hole. h'otelor fi and F should be mentioned Î Î ΐϊή riivdl dOîĂp'âfÎtbil oii od_;. admfiGibiȚ .peniiu 'to proceed, -dffe itteoperire, known. This reef is' Țuâcțîie 'dfe tempera de tip de ferir' Î'șî'de'pfS'ce'îifui'de dih hydrogen - the atmosphere of preiufeare to bensaii-k irri - all the examples of re-rises described previously, rolls 37, 73 and 74 / -dispriserift-; âppo0ere &,; Șuppaietei ea · baii. of half-life topopil · -Ș can. · be seen, - by._; preferenceLfefș o-supitaiât'ă ·, d <p? e laugh-p'ptpa ^ şa âȘ · efe ipătrafifet ^ uf 1ΦΗ>. 8

This will facilitate the removal of any metal film from these rollers, as a result of the clamping. the woven fabrics · 37, 73 and 74, dispdfeb irripririrOpirircă baths of molten metal 3, can be used, so I can find the streams that are used are easily separated from the surface of the Bath. This will make the cleaning operation easier.

tBfciltoâfe'â of a preferred OxemplU Or Uria of coiribinatil dd devices depends on the rigid restrictions and the number of factors that determine a high quality coverage. These factors depend on the equipment available, the coating metal used, the desired characteristics for the final product covered on a single part and so on. For example, in those embodiments described above, wherein the jet finishing is completed by introducing a non-oxidizing atmosphere inside the hood, for example the installation of FIG. 8, superior technical effects are obtained, such as, making a surface it baths the coating metal 3 very good, even at very low speeds, reduction of defects caused by slag, 0 superior finishing of the deposited metal sheet and so on. .

In an exemplary embodiment, as shown by Ouni, Figs. 18 and 19 use a non-oxidizing gas finishing jet, the tiara is disposed outside the chamber, but before band 1 comes into contact with atmospheric air. In the case of this embodiment, · the possibility of fine metal droplet accumulations in the F hood is reduced and the metal droplets that could be deposited on the uncoated face 1 of the metal strip 1 are eliminated. On the other hand, the non-flush gas used in jet finishing is not available to create a positive pressure on the air.

in the case of the coating installation shown in fig. 1, the atmospheric air is used for the finishing. The finishing operation is carried out easily, without aggravating the problems related to metal deposits. Gas consumption with non-oxidized action 'is also reduced.

Embodiment examples that use a 'Single roll 37 are caraeterizdte' through a conateuottva simplicity, -which on the sticks^: a reduction in the ferries between 'baridâufKtetali'GS 1 and fndftîfe®^;,Js '= ethyl'^; the purpose of avoiding the making of the beast in the bath of the apheoptrite. In this case, the teftsIt 'iCtordătă · tf me lYifitâî • âiteft ipip''âtodffitfî^! 'fe (' dd '^ - nd' IWipî'if · rolidi '· cKfâe-efiiSfifiîizafeit a fioiiâ' rofehfî jîI Î7 rbâTiz ^ zâ fiSSSSafeă »du aeri a 'fa' the network india riaîâ J'M fig. lb. millet 1'doIțÎcI, through the formation of mehwwni

If, it will lead to a slight loss of meniscus. A closer contact with k - metal tape 1 will cause the iron to dissolve from the tape 1 which passes into the metal melting bath 3. The coating dc installation where ε-two rollers 17 and 23 are provided is more complex and imposes certain restrictions on to the profile of the builder 1.

The coating installation provided with three rollers 37, 73 and 74, as shown in fig. 5 and 16, sum up all the technical effects realized in the school.

A metal band 1 on the basis of iron, about 700 mm in size, was coated on one side with zinc, useful for an installation like the one shown in FIG. 1. At a strip speed of 12.2 m / min, the temperature of the strip 1 at the entrance to the hood B was 47O ... 465 ° C, and the bath temperature was 465 ° C.

A protective, non-oxidizing, nitrogen-based atmosphere was introduced into the hood B with a flow rate of 70Ό m³/ H. At dew point 10 a dew point of 12 ° C was recorded, together with less than 120 ppm oxygen.

The hole of the nozzle 20, where the jctuil is directed, had a diameter of 0.76 mm and air was used at a pressure of 0.063 kgf / cm². The nozzle was maintained at a height of approximately 147-mm above the level of the metal tubing 3 and was directed upwards at an angle of about 2 or 3 °. The roller 17 had a diameter of 310 mm. The nozzle 20 was kept at a distance of about 4.76 mm from the lacquered part of the metal strip 1.

As a result of the aforementioned working method, a single-layer zinc layer was made on the metal strip 1 on an iron base, which has a coating weight of 0.916 g / cm².

The samples subjected to the adhesion tests behaved accordingly. The uncoated part 1 of the strip 1 was provided with a fine oxide film.

In another embodiment, an iron-based metal band 1, approximately 700 mm in size, has been coated with aluminum egg, using the installation shown in FIG. 1. ha «speed of band 1 of 4.5 m / min, this was introduced in the hood B at a temperature of band 1 of about 710 ° C. Melted metal bath 3. had a temperature that was maintained at 685 ° G.

A protective atmosphere, non-oxidized, nitrogen-based, was introduced into the hood B at a flow rate of 300 m³/ H. At roll 10, a weight of nine of 12.2 ° C was recorded, together with less than 100 ppm of oxygen. ">

The nozzle nozzle 20 had a diameter of .0762, whereby air was directed to a pre22 suction of 0.052 kgf / cm². The nozzle nozzle 20 was kept at a height of about 101.6 mm. The nozzle nozzle 20 was maintained at a distance between 3.17 and 4.70 mm from the covered part of the metal strip 1. The respective nozzle was maintained at a distance of approximately

101.6 mm above the e-level of the metal bath 3 and was directed upwards at an angle of about 10 °. The roller 10 had a diameter of 304 mm.

Following the coating process, the metal strip 1 was provided on the part I with a layer of aluminum, striped having a weight of about 0.915 g / cm². The samples subjected to conventional test tests have confirmed that the coating has adequate adhesion.

The installation, according to the invention, has the following advantages:

- allows a uniform and uniform coating to be made on one side of the metal strip;

- has a low consumption of protective gases;

- does not allow the formation of oxide layers or material deposits on the uncoated surface of the metal strip.