EP4299785A1 - Dispositif et procédé pour un soufflage sous humidité controlée après l'application d'une couche sur un produit plat en acier - Google Patents

Dispositif et procédé pour un soufflage sous humidité controlée après l'application d'une couche sur un produit plat en acier Download PDF

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Publication number
EP4299785A1
EP4299785A1 EP23164714.0A EP23164714A EP4299785A1 EP 4299785 A1 EP4299785 A1 EP 4299785A1 EP 23164714 A EP23164714 A EP 23164714A EP 4299785 A1 EP4299785 A1 EP 4299785A1
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EP
European Patent Office
Prior art keywords
gas
stripping
stripping gas
flat steel
dew point
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EP23164714.0A
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German (de)
English (en)
Inventor
Christian Pfob
Johann Strutzenberger
Christian Karl Riener
Harald Unger
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Voestalpine Stahl GmbH
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Voestalpine Stahl GmbH
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Priority claimed from EP22182311.5A external-priority patent/EP4299784A1/fr
Priority claimed from EP22182309.9A external-priority patent/EP4299783A1/fr
Application filed by Voestalpine Stahl GmbH filed Critical Voestalpine Stahl GmbH
Publication of EP4299785A1 publication Critical patent/EP4299785A1/fr
Pending legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/003—Apparatus
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
    • C23C2/06—Zinc or cadmium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/14—Removing excess of molten coatings; Controlling or regulating the coating thickness
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/14—Removing excess of molten coatings; Controlling or regulating the coating thickness
    • C23C2/16—Removing excess of molten coatings; Controlling or regulating the coating thickness using fluids under pressure, e.g. air knives
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/14—Removing excess of molten coatings; Controlling or regulating the coating thickness
    • C23C2/16—Removing excess of molten coatings; Controlling or regulating the coating thickness using fluids under pressure, e.g. air knives
    • C23C2/18—Removing excess of molten coatings from elongated material
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/14—Removing excess of molten coatings; Controlling or regulating the coating thickness
    • C23C2/16—Removing excess of molten coatings; Controlling or regulating the coating thickness using fluids under pressure, e.g. air knives
    • C23C2/18—Removing excess of molten coatings from elongated material
    • C23C2/20—Strips; Plates
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/50—Controlling or regulating the coating processes
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/50—Controlling or regulating the coating processes
    • C23C2/51—Computer-controlled implementation
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/50—Controlling or regulating the coating processes
    • C23C2/52—Controlling or regulating the coating processes with means for measuring or sensing
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/50—Controlling or regulating the coating processes
    • C23C2/52—Controlling or regulating the coating processes with means for measuring or sensing
    • C23C2/525—Speed of the substrate

Definitions

  • the present invention relates to a device with which flat steel products in a melt pool can be coated with a layer based on zinc (Zn) or zinc-aluminum-magnesium (ZnAlMg), for example as a protective coating, and can be blown off in a controlled manner on the exit side of the melt pool. This is also about a corresponding procedure.
  • Zn zinc
  • ZnAlMg zinc-aluminum-magnesium
  • flat steel products 100 such as steel strips or steel sheets, are coated with a zinc (Zn) or ZnAlMg alloy to improve corrosion resistance.
  • Zn zinc
  • ZnAlMg alloy zinc alloy melt pool 11
  • this usually happens by introducing the flat steel product 100 from a furnace into a zinc alloy melt pool 11, as in Fig. 1 indicated using an exemplary device 150.
  • it is typically introduced into the bath 11 on the input side E through a trunk 12 with an inert atmosphere.
  • the flat steel product 100 is deflected by one or more (zinc bath) rollers 13 and moved upwards out of the bath 11 on the exit side A.
  • the alloy melt film adhering to the front and back of the flat steel product 100 is stripped (also blowing off) with a gas jet from the gas nozzles 15 of a stripping nozzle device to the target thickness (in the micrometer range) or to the target surface area (in g/m 2 ). called) and the flat steel product 100 is then placed in a cooling area 16 transferred.
  • This continuous process is generally called hot-dip coating.
  • the flat steel product 100 can then be rolled treated by subjecting it to a skin pass process step and/or a bending-stretching process.
  • the flat steel product 100 can be chemically treated.
  • Flat steel products 100 e.g. in the form of steel strips
  • Oiling can be done, for example, using an oiling machine.
  • a freshly hot-dip coated flat steel product 100 can have surface defects or defects, depending on the alloy composition and the specific process control.
  • zinc vapor can form, which can have a negative influence on the surface of the hot-dip coated flat steel product 100.
  • the process of blowing off on the exit side A of the melt pool 11 also has an influence on the surface quality.
  • Patent EP0172682B1 from Armco Inc. issued in 1985 was registered, it is about the reduction or avoidance of oxygen in the area of the stripping nozzle and in the area of the steel strip emerging from the zinc bath and about the control of zinc vapor in connection with the hot-dip coating of an iron-based metal strip.
  • an oxygen-reduced atmosphere is provided in an enclosed area in which the stripping nozzle is also located, instead of the ambient air that is normally present. Since zinc would evaporate heavily in this atmosphere, a small proportion of water vapor must be added to the oxygen-reduced atmosphere.
  • the enclosed area sits directly above the melt pool surface and thus forms a hermetically enclosed space.
  • the oxygen-reduced atmosphere in this room is intended to improve the stripping process and the small proportion of water is intended to prevent the formation of zinc vapor on the surface of the immersion bath.
  • the moisture content in the hermetically enclosed space is adjusted so that zinc vapor cannot form.
  • a wide slot nozzle is used to blow air, gas or steam against the zinc-coated strip for stripping purposes.
  • the nozzle slot is larger in the area of the belt edges than in the area of the middle of the belt in order to take into account the fact that the belt can have a curved shape on the exit side of the bath.
  • the main problems here are often surface defects in the ZnAlMg layer.
  • “marble effect”, “toothpick” or “beach pattern” defects can form on the ZnAlMg layer. or slag formation may occur.
  • There are patents e.g EP20130826634 AM/JMMaigne ; JP20080256208 NSSMC/ Oohashi et al. ), which attempt to remedy similar surface defects (gloss effects or displaced oxide skins) by means other than the present invention (reducing the Oz content in the area around the stripping nozzle).
  • Similar surface defects can also occur under certain circumstances in Zn layers that contain an Al content (the Al content can, for example, be less than 1% by weight).
  • the task now is to provide a device and a method for being able to coat flat steel products with a ZnAlMg layer or a ZnAl layer, which have a particularly durable and robust protective effect in terms of corrosion, with the surface of this layer coating being particularly homogeneous and without There should be marbling (without “marbel effect”) and/or toothpick errors (without “toothpick”).
  • marbling without “marbel effect”
  • toothpick errors without “toothpick”.
  • the device and the method should consume as little energy as possible, be inexpensive to operate and be robust in use.
  • a corresponding device which uses a continuous (hot-dipping) process and which allows a flat steel product to be provided with a metallic ZnAlMg layer or a ZnAl layer, which can serve, for example, as a (protective) coating .
  • This layer is intended to protect both sides of the steel substrate of the flat steel product from external influences.
  • the corresponding immersion bath is referred to as a zinc alloy melt bath (or zinc melt bath for short), whereby the term zinc alloy melt bath is intended to include both a melt bath which contains mostly zinc (Zn) and a small admixture of aluminum (Al) (e.g. less than 1% by weight, as well as a melt pool containing a ZnAlMg alloy.
  • the layer to be applied on both sides is also referred to here as a Zn-containing (protective) layer.
  • the moisture content of the stripping gas can be defined for at least some of the embodiments for the device and the corresponding method by the volume fraction (here called condition B1), which is in the range between 200ppm and 43700ppm.
  • the volume fraction is in the range 500ppm to 9980ppm in at least some of the embodiments.
  • the moisture content of the stripping gas can be defined for at least some of the embodiments for the device and the corresponding method by a dew point (here called condition B2) which is greater than -39°C and less than +30°C.
  • condition B2 a dew point which is greater than -39°C and less than +30°C.
  • the dew point of the stripping gas is in the parameter range - 29 ° C to + 7 ° C in at least some of the embodiments.
  • conditions B1 and B2 define areas that largely overlap. Deviations may only occur in the marginal values due to rounding sizes.
  • the moisture content of the stripping gas can be defined for at least some of the embodiments for the device and the corresponding method by using a mixture of dry gas and gaseous water vapor, which is controlled and changed so that it is always unsaturated (whereby also In this alternative approach, condition B1 and/or B2 is/are fulfilled).
  • the unsaturated stripping gas always only contains water in the vapor phase.
  • a stripping gas is used whose proportion (moisture content) of gaseous water vapor is kept so low that the stripping gas is unsaturated in relation to the water vapor content. This means that the instantaneous dew point of the stripping gas is always smaller than the instantaneous temperature of the stripping gas. This statement regarding the unsaturated state also applies to changing gas pressure and/or changing temperature of the stripping gas.
  • the unsaturated stripping gas can also be defined for all embodiments by being considered unsaturated as long as it only contains superheated water vapor.
  • the stripping gas In the unsaturated state, the stripping gas is a homogeneous, single-phase mixture containing only a gaseous (no solid or liquid) phase. In the unsaturated state, the stripping gas has a relative humidity that is less than 100%.
  • the dew point upper limit of +30°C - which corresponds to a volume fraction of 43700 ppm of water in the stripping gas - is defined in order to prevent the condensation of water when the stripping gas ejected from the stripping nozzle is mixed with the ambient gas (or the ambient air ) in the area around the wiper nozzle.
  • the corresponding method and the device are based on specifying the moisture content required at the point of impact of the stripping jet on the flat steel product in a controlled manner in such a way that marbling and/or toothpick errors are avoided.
  • the formation of condensate must be avoided.
  • the moisture content i.e. the water vapor content
  • the moisture content is controlled by monitoring the current dew point of the stripping gas and keeping it within a suitably predetermined parameter window (condition B2).
  • condition B2 the moisture content
  • Condensing water would have a negative impact on the stripping process and the surface quality of the galvanized strip.
  • a controller or control unit of the device can implement a moisture adjustment protocol in order to be able to react appropriately to changes in the current moisture content and to ensure compliance with conditions B1 and/or B2.
  • the moisture content required in each case is provided directly via the stripping gas.
  • the stripping gas serves as a carrier or transport medium for the very small amount of water vapor required here.
  • a steam gas stream is introduced into the dry stripping gas, here called dry gas stream, in order to mix the dry gas and the steam gas stream.
  • the dry gas stream preferably comprises nitrogen or consists of nitrogen. In all embodiments, the dry gas stream can also contain another inert gas instead of nitrogen.
  • the moisture content of the stripping gas can be determined, for example, with a moisture sensor (e.g. a thermal or capacitive dew point sensor), which is arranged between the feed point for the gaseous water vapor and the nozzle opening of the stripping nozzle, can be measured and, in further possible embodiments, also regulated.
  • a moisture sensor e.g. a thermal or capacitive dew point sensor
  • All embodiments involve the application of a Zn-containing (protective) layer to a flat steel product, the layer thickness of this layer should correspond to a target thickness (according to a corresponding specification).
  • This layer is created by passing the flat steel product through a zinc alloy melt bath and blowing off the controlled “moistened” stripping gas on the exit side of the bath using a stripping nozzle device which comprises at least one gas nozzle per side of the flat steel product.
  • marbling and/or toothpick defects do not occur under certain environmental conditions. This can be the case, for example if the ambient air is sufficiently humid (e.g. when the air humidity is high in summer). The ambient air is sucked in by the stripping gas that emerges from the nozzles and is swirled with the stripping gas. The occurrence of such surface defects also depends on numerous other parameters (such as the bath temperature). At low bath temperatures, the tendency to form surface defects can increase even when the ambient air humidity is high. If - according to the invention - you ensure a suitable moisture content of the stripping gas itself, then hot-dip coating and blow-off are largely independent of the currently prevailing and uncontrollable environmental conditions. This means that hot-dip coating and blowing becomes more robust against external influences.
  • all embodiments include at least one means (e.g. implemented as a hardware device) for determining gas moisture or the moisture content in or on the stripping nozzle device in order to determine (e.g. measure) the gas moisture before or as the stripping gas exits (in the direction of the front or back of the flat steel product).
  • at least one means e.g. implemented as a hardware device for determining gas moisture or the moisture content in or on the stripping nozzle device in order to determine (e.g. measure) the gas moisture before or as the stripping gas exits (in the direction of the front or back of the flat steel product).
  • This means for determining gas moisture is preferably located. of the moisture content, or a sensor of these means, in a gas supply line at a location that is in the flow direction at a point after the dry gas stream and the water vapor gas stream have been merged/mixed.
  • this means can be used to determine gas moisture or of the moisture content, or a sensor of this device, is located in or on the gas nozzle.
  • this means can be used to determine gas moisture or of the moisture content, or a sensor of this device, are located in a gas supply line and in the gas nozzle.
  • the method is characterized in all or at least some of the embodiments in that the ZnAlMg layer or the ZnAl layer is applied to both sides of a flat steel product according to a target specification by passing the flat steel product through a zinc alloy melt bath (ZnAl; ZnAlMg). moves and on its output side stripping gas exits through a nozzle lip gap of at least one gas nozzle towards the front and through a nozzle lip gap of at least one gas nozzle towards the back of the flat steel product in order to blow off the layers on both sides in accordance with the target specification.
  • ZnAl zinc alloy melt bath
  • the ambient air humidity in the area of the device can optionally also be determined in at least some of the embodiments. Since the device or the method sucks in ambient air when blowing off (as already mentioned), more precise adjustments to the gas humidity (moisture content) of the stripping gas can be made taking into account the currently existing ambient air humidity. If, for example, the current ambient air humidity is particularly low, the gas humidity of the stripping gas is usually very important in order to reliably avoid surface defects. In “humid” environmental conditions, it is not always absolutely necessary to add water vapor to the stripping gas in order to reliably avoid the formation of marbling and/or toothpick defects.
  • the gas moisture (moisture content) of the stripping gas is adjusted/adjusted through the use of a steam device by providing a correspondingly large flow rate of the steam gas stream to the actual flow rate of the dry gas stream provided and combining/mixing it with the dry gas stream. That is, in these embodiments, the flow rate of the steam gas stream is actively adjusted to the actual flow rate of the dry gas stream provided (called control or regulation of the steam gas stream source).
  • the dry gas flow can be reduced if the steam gas flow is increased (and vice versa).
  • the gas moisture (moisture content) of the stripping gas is adjusted/adjusted by adjusting both the flow rate of the dry gas stream and the flow rate of the water vapor gas stream. This can be done, for example, using controllable gas valves in a dry gas supply and in a steam gas supply. Or the delivery quantity of the dry gas stream source and the steam gas stream source is controlled or regulated.
  • the gas humidity (moisture content) of the stripping gas can be adjusted/adjusted by a mixing valve in the area where the two gas streams come together to adjust one or both flow rates.
  • the close range of the device is defined in at least some of the embodiments as a volume in a range of 1 m 3 to 10 m 3 .
  • the environment of the device is defined in at least part of the embodiments as a volume that is larger than 10 m 3 .
  • the device or the stripping nozzle system can include an automatic support control which is designed to automatically adjust the flow rate of the (stripping) gas in order to keep the target thickness of the layers to be applied essentially constant.
  • the automatic circulation control is preferably designed so that it is able to compensate for fluctuations in one or more system parameters and process parameters.
  • the unavoidable impurities of the alloys are in a range that is significantly smaller than 1 percent by weight (wt.%), preferably the sum of all unavoidable impurities is less than 0.5 percent by weight.
  • a surface can be produced that shows no or negligibly low marbling and no or negligibly low toothpick defects.
  • the gas humidity (moisture content) of the stripping gas can be kept substantially constant or adjusted (e.g. if the humidity in the vicinity or in the surroundings of the device changes) in order to produce consistent layers (that are within the specified specification). receive.
  • the stripping nozzle device can optionally be followed by a belt stabilization device, which serves to automatically stabilize the movement of the flat steel product.
  • a cooling surface or a cooling area can optionally be provided on or in the stripping nozzle device in order to remove excess water vapor if it occurs despite all measures to provide a controlled area for condensation.
  • An outlet can also be provided in this area so that condensate can be drained from time to time.
  • the cooling surface or cooling area should always be cooler than the current dew point temperature of the stripping gas.
  • a device for condensing excess water vapor can also be used in the supply line for the water vapor gas.
  • the flat steel product can be subjected to an annealing or tempering step in a zinc alloy melt bath at a temperature of approximately 765 ° C (or at a lower or higher temperature) before hot-dip coating.
  • the flat steel product may be cold-rolled after hot-dip coating (for example, using smooth cold rolls and/or using skin-pass rolls with a specific roughness).
  • the steel strip can be subjected to a bending-stretching process in-line in addition to the tempering process or alone in order to increase the flatness of the steel strip.
  • the flat steel product in strip form for example as deep-drawing steel, mild steel, structural steel, steel of a higher-strength steel type, can each be cleaned in strip form in a so-called pretreatment or pre-cleaning in the continuous hot-dip galvanizing system by means of a combined dipping/brushing/electrolytic cleaning of rolling oil and rolling abrasion, rinsed with water and dried.
  • the cleaned, dried flat steel product in strip form then enters the annealing furnace of a continuous hot-dip coating, where it is preheated, heated and brought to the annealing temperature under protective gas.
  • the flat steel product in strip form is cooled to a strip immersion temperature and dipped into the ZnMgAl alloy melt pool. After the bath exits, the flat steel product in strip form is adjusted to the desired layer thickness using the stripping gas at the stripping nozzles according to the embodiments described and claimed here. In a subsequent cooling tower, the zinc alloy melt is solidified on the steel strip.
  • the flat steel product can be re-rolled in strip form in-line (the continuous hot-dip galvanizing plant) in a skin pass stand and a specified roughness can be imprinted.
  • the flat steel product in strip form can be coated with anti-corrosion and forming oil in an oiling machine and finally wound up on the reel.
  • the steel product which is in the form of a wound steel strip, can be coated with a paint in a strip coating system after being wound on the reel.
  • the flat steel product in strip form is subjected to a chemical post-treatment with an organic/inorganic passivation layer using a coater after bending-stretching-straightening and/or tempering (coating device) coated and then dried. Then the flat steel product 100 is inspected for surface defects and wound on the reel if no marbling or toothpick defects were found.
  • All embodiments may include a PC or other computer to automatically control the moisture content of the stripping gas and/or to manually operate the stripping gas within a dew point window.
  • the moisture content of gases can be described in different ways. It is common to specify the dew point in °C, to specify the mass fraction of water per volume of the gas in g/m 3 (also called absolute humidity) and to specify the volume fraction in ppm (parts per million parts, also ppm V).
  • the dew point describes the temperature at which water vapor in a gas (here in the stripping gas AG) begins to condense. When the dew point temperature is reached, the gas can no longer absorb additional water vapor, ie the gas is saturated with water vapor.
  • frost point can be used at temperatures that are below 0 °C. However, we use the term dew point throughout (even at negative temperatures).
  • Pure nitrogen gas which is used as stripping gas AG for blowing off, typically has a temperature of 10 to 30°C. However, the nitrogen gas can also be heated before blowing off (eg to temperatures in the range 50 to over 200 ° C). Warm stripping gas AG can absorb more water vapor, so the dew point can be higher. In cold stripping gas AG the situation is reversed. In addition, stripping gas AG can absorb less water vapor under high pressure than at lower gas pressure. Furthermore, it should be noted that the condensation of the water vapor usually occurs in the lines and components (eg in the nozzles 15) of the gas-carrying system.
  • the moisture content of the stripping gas AG is preferably defined by setting a minimum dew point TP min .
  • a maximum dew point TP max can also be set, which is + 30 ° C (which corresponds to approximately 43700 ppm H 2 O in the stripping gas AG).
  • the temperature difference ⁇ T can preferably be at least 5°C and particularly preferably at least 10°C.
  • TP defines the instantaneous dew point in the stripping gas stream AG and T AG defines the instantaneous temperature of the stripping gas stream AG.
  • a temperature difference ⁇ T for example, the fact can be taken into account that when the pressure of the stripping gas AG increases, the tendency for the water vapor content to condense increases.
  • a temperature difference ⁇ T which is to be understood as a kind of safety margin, it can be ensured that condensation does not form even if the pressure of the stripping gas AG increases slightly.
  • the safety margin also prevents condensation in the stripping gas AG from occurring due to fluctuations in the control of the water vapor gas added.
  • the dew point TP of the stripping gas AG is therefore set to values in the range -39 ° C ⁇ TP ⁇ 18 ° or preferably to values in the range - 29 ° C ⁇ TP ⁇ + 7 °C to be set.
  • a device 150 (see for example Fig. 2 ), which is used to apply a layer 10 (see Fig. 4 ) is designed on the front V and back R of a strip-shaped flat steel product 100.
  • the components of the immersion bath 11 are not shown here (it will be shown on Fig. 1 Reference, which shows exemplary components).
  • the exit side of the immersion bath 11 is in Fig. 2 marked by the letter A.
  • the flat steel product 100 is moved vertically upwards in the direction of the directional arrow B.
  • the stripping nozzle device 14 comprises at least one gas nozzle 15 for blowing off the front side V and at least one gas nozzle 15 for blowing off the back side R of the flat steel product 100.
  • the stripping nozzle device 14 only includes a gas nozzle 15 for blowing off the front side V.
  • the gas nozzle 15 for blowing off the back side R is designed accordingly.
  • two stripping nozzle devices 14 are provided, which comprise opposing nozzles 15.
  • the layers 10 on both sides V, R are produced by passing the flat steel product 100 from an input side E to an output side A through a zinc melt bath 11 (see e.g Fig. 1 ) and is blown off with (stripping) gas AG on the output side A by means of the stripping nozzle device 14.
  • the purpose of the stripping nozzle device 14 is to strip off the excess (still liquid) ZnMgAl layers or ZnAl layers (layers 10) on the flat steel product 100 in a controlled manner with the (stripping) gas AG after exiting the bath 11.
  • the specification defines, for example, the target thickness or the edition per side V, R), and that no marbling and/or no toothpick errors occur. In some of the embodiments, for example, it may be about avoiding these “errors” when environmental conditions change in the production area (e.g. in the factory hall). go. Even if the ambient air humidity f UG should change in the wider surroundings of the device 150 (e.g. in the factory hall) or in the immediate vicinity, the device 150 and the method according to the invention can ensure that no marbling and/or toothpick stains occur. Errors occur/occur and that the layers 10 can continue to be produced according to specification.
  • the target surface support (coverage per belt side) can be in the range from 20 to 200 g/m 2 and particularly preferably in the range from 30 to 160 g/m 2 .
  • the stripping nozzle device 14 comprises at least one gas nozzle 15 per side V, R (eg two gas nozzles 15 that face each other, as in Fig. 3 and 4 indicated).
  • Nm 3 stands for standard cubic meters.
  • a standard cubic meter is the amount of a stripping gas AG contained in a volume of one cubic meter. This applies at a temperature of 0 degrees Celsius and a pressure of 1.01325 bar.
  • dry gas TG is understood here to mean an inert gas that has a dew point that is approximately -70°C and below. This corresponds to a water vapor content of approx. 5 ppm and below.
  • the dry gas TG therefore has a very low residual moisture (also called traces of moisture) in a range that is common for industrial gases.
  • the dry gas TG used here can, for example, correspond to the specifications of the “Specification for Industrial nitrogen”, British Standard BS 4366:1993.
  • the water content of the gaseous Nitrogen dry gas TG (cf. paragraph 8) is set at a maximum of 10/10 6 , which corresponds to 10ppm.
  • the dry gas TG should have a residual moisture that is less than 10 ppm and which is preferably less than 5 ppm.
  • the device 150 includes a dry gas supply or dry gas source 18 (see Fig. 2 ).
  • a dry gas supply or dry gas source 18 for example, a gas tank, a gas bottle or a gas line (which comes, for example, directly from the gas supplier or from an air separation apparatus that works, for example, according to the Linde process) can serve as a source 18.
  • the device 150 can, for example, also have two dry gas supplies or dry gas sources 18 (see Fig. 3 ), one of the sources 18 being assigned to a stripping nozzle device 14.
  • the device 150 can also include, for example, a dry gas supply or dry gas source 18, which feeds both stripping nozzle devices 14.
  • the device 150 includes at least one steam device or source 50 (see Fig. 2 ).
  • an evaporator or a gas humidifier for example using ultrasonic atomization, can serve as source 50.
  • this water vapor device or source 50 is fluidly connected to the gas nozzle 15, as in Fig. 2 indicated.
  • the source 50 is connected to a dry gas supply (line) 21 via a water vapor gas supply (line) 22.
  • the two gas supply lines 21, 22 are fluidly connected to one another in a T-shaped area 19.
  • the dry gas stream is represented by an arrow TG and the water vapor gas stream by an arrow WG.
  • one or more steam generator(s) is/are preferably used as steam device(s) or source(s) 50, which is/are designed as a pure steam generator, which produces gaseous water vapor WG from purified or highly purified water , or generate a water vapor gas stream WG.
  • the steam device 50 can preferably comprise a pure steam generator and, for example, a valve that can regulate the steam gas flow WG through the line 22.
  • the pure steam generator and/or the valve can in all embodiments be connected to a control of the device 150 and/or to the device for determining the gas moisture 20 or 26 (not shown).
  • the water vapor gas stream WG can also come from condensate recovery.
  • the device 150 can, for example, also have two steam devices or sources 50 (see Fig. 3 ), one of the sources 50 being assigned to a stripping nozzle device 14.
  • the gas streams TG and WG are combined and mixed.
  • the gas mixture that is created is referred to here as stripping gas AG.
  • the stripping gas AG flows from the area 19 through the gas nozzle 14 in the direction of the front V or back R of the flat steel product 100.
  • the stripping gas AG which exits through a (gas) nozzle lip gap 17 of the respective gas nozzle 14, is in Fig. 2 and 3 symbolized by three parallel arrows.
  • a mixing chamber can be provided in all embodiments in order to mix the gases TG, WG.
  • the air humidity f UG in the close area and/or in the surroundings of the device can be continuously or from time to time 150 can be determined (e.g. by direct or indirect measurement) in order to be able to adjust the moisture content of the stripping gas AG accordingly if the ambient conditions change.
  • this adaptation to the environmental conditions is optional.
  • a water vapor gas stream WG can only be supplied to the stripping gas AG in all embodiments if the Ambient conditions themselves should not be sufficient (e.g. if the ambient air is too dry) to avoid these errors.
  • the device 150 can comprise at least one device 20, which is designed and arranged accordingly to determine the moisture content in the stripping nozzle device 14.
  • the device 20 is designed to determine the current moisture content of the stripping gas AG (eg in the form of signals or measured values that contain information about the current dew point TP and / or the moisture content in ppm or as absolute or relative humidity).
  • the device 20 comprises two sensors 23, 24, both of which protrude into a gas line 25.
  • the device 20 comprises a combined or integrated sensor 23/24, which projects into the respective gas line 25.
  • the moisture content of the stripping gas AG can be determined additionally or alternatively before or as the stripping gas AG exits in the direction of the front V and/or back R of the flat steel product 100.
  • the sensor 23 can be, for example, a humidity sensor and the sensor 24 can be a temperature sensor. Both sensors 23, 24 are connected to a module 26 of the device 20 via lines KV3, KV4.
  • combined or integrated sensors can also be used that measure the moisture content and the temperature T AG of AG.
  • Fig. 3 An embodiment is shown in which a combined or integrated sensor 23/24 is provided for each stripping nozzle device 14. The corresponding communications line is designated KV5.
  • sensors can also be used which, for example, measure the pressure dew point as well as the absolute moisture content f and temperature T AG of the gas AG.
  • Digital and/or analog sensors can be used in all embodiments.
  • a dew point measuring device can also serve as device 20.
  • Suitable humidity sensors include sensors that are based on the principle of absorbing electromagnetic waves (microwave absorption sensors) or that detect a change in the dielectric constant (capacitive sensors).
  • microwave absorption sensors sensors that are based on the principle of absorbing electromagnetic waves
  • capacitor sensors detect a change in the dielectric constant
  • An example is a polymer sensor that is designed to measure moisture in gases in the temperature range of interest here.
  • the moisture content of the stripping gas AG can also be determined and processed in all embodiments by measuring the volume fraction in ppm (also ppm V).
  • a measuring cell with a moisture sensor eg a sensor that adsorbs the moisture in the gas AG and then breaks it down electrolytically
  • a moisture sensor eg a sensor that adsorbs the moisture in the gas AG and then breaks it down electrolytically
  • the relationship between the dew point temperature in °C and the volume fraction in ppm is not linear, but is exponential (see also equation (1)).
  • the present context is based on the following estimates/approximations, as shown in Table 1.
  • the absolute humidity f (in g/m 3 ) of gases and thus also the absolute humidity f UG of the ambient air used here are also temperature-dependent.
  • the dew point in °C and the volume fraction of H 2 0 in ppm are independent of temperature and apply regardless of the gas type).
  • the dew point in °C and the volume fraction of H 2 O in ppm are preferably used here.
  • the stripping gas AG is a dry nitrogen gas, with a dew point TP between - 77 ° C and - 72 ° C and with a moisture content that is between 1.8ppm and 3.8ppm.
  • a nitrogen gas meets the requirements of the previously mentioned British Standard, as the residual moisture is less than 10ppm.
  • sample numbers 53 to 74 Only for the examples with sample numbers 53 to 74 does any strong marbling no longer occur. This significant reduction in severe marbling is achieved by adding a small proportion of the water vapor gas WG with at least 208ppm (sample number 53) and up to 9978ppm (sample number 74) to the dry nitrogen gas TG.
  • the dew point of the stripping gas AG for sample numbers 53 to 74 is between - 39°C (sample number 53) and + 7°C (sample number 74).
  • a condition B1 can be derived from this, as follows:
  • the stripping gas AG should always have a moisture content, or a proportion of the gaseous water vapor WG, that is greater than 200ppm and less than 43700ppm is.
  • the lower limit of 200ppm results from the test results shown in Table 1 (208ppm rounded down to 200ppm), the upper limit of 43700ppm ensures that there is no condensation of water in the area around the wiper nozzle, as already mentioned above.
  • a condition B2 can also be derived from this, as follows:
  • the stripping gas AG should always have a dew point TP that is greater than - 39°C and less than + 30°C.
  • the lower limit of -39°C results from the test results shown in Table 1, the upper limit of +30°C ensures that there is no condensation of water in the area around the wiper nozzle.
  • sample numbers 58 to 74 Only for the examples with sample numbers 58 to 74 does marbling no longer occur (with the exception of sample number 59). This significant reduction in marbling is achieved by adding a small proportion of the water vapor gas WG with at least 552ppm (sample number 58) and up to 9978ppm (sample number 74) to the dry nitrogen gas TG.
  • the dew point of the stripping gas AG for sample numbers 58 to 74 is between - 29°C (sample number 58) and + 7°C (sample number 74).
  • a further preferred condition B1 can be derived from this, as follows:
  • the stripping gas AG should always have a moisture content, or a proportion of the gaseous water vapor WG, which is in the range 500ppm to 9980ppm, with these ppm details being rounded down or up.
  • the preferred condition B2 can also be derived from this, as follows:
  • the stripping gas AG should always have a dew point TP that is in the range between -29°C and +7°C.
  • condition B2.1 the respective dew point TP of the stripping gas AG is below the current temperature T AG of Stripping gas AG.
  • This condition (TP ⁇ T AG ). is referred to here as condition B2.1.
  • condition B2.1 has the advantage that it is independent of the temperature T AG of the stripping gas AG. If, for example, the stripping gas AG has a temperature T AG of 27°C, then in order to fulfill condition B2.1 the dew point TP of the stripping gas AG must be below + 27°C.
  • the preferred condition B2.1 can also be defined as follows: between the temperature T AG of the stripping gas AG and the dew point TP of the stripping gas AG there should always be an optional safety margin ⁇ T, as follows: TP ⁇ T AG - ⁇ T.
  • the dew point TP of the stripping gas AG should be below + 17 ° C if the temperature T AG of the stripping gas AG is, for example, 27 ° C.
  • This condition B2.1 also applies when the gas pressure and/or the temperature T AG of the stripping gas AG changes.
  • the additional condition B3 can also be defined, which specifies that the stripping gas AG is a gas that is in an unsaturated state.
  • This condition B3 also applies when the gas pressure and/or the temperature T AG of the stripping gas AG changes.
  • Condition B3 is considered an additional condition that can be met in all embodiments in addition to conditions B1 and/or B2 and/or B2.1.
  • the determination/measurement/monitoring of the air humidity f UG of the environment or the close area and/or the air temperature T L can, as already described, be carried out directly or indirectly in all embodiments.
  • Indirect measurement here includes, among other things, measuring the air temperature T L and the relative humidity r and calculating/deriving the absolute local humidity f UG from this.
  • the current flow rate of the stripping gas AG can be adjusted automatically in a known manner (for example in terms of control technology through an automatic support control of the device 150) in order to keep the target thickness or the support per side of the layers 10 to be applied essentially constant, if one or more of the system parameters and/or process parameters change should.
  • the supplied amount of water vapor gas stream WG must then be adjusted accordingly to ensure that the stripping gas AG corresponds to the conditions B1, B2, B2.1, B3 of the invention in terms of moisture content.
  • Fig. 4 also shows the nozzle distance (defined parallel to the y-axis) between the nozzles 15 and the respective strip side (front V, back R) of the flat steel product 100, as well as the thickness (defined parallel to the x-axis) of the nozzle lip gap 17 (called the height of the nozzle opening ).
  • the nozzle lip gap 17 serves as a gas outlet gap of the stripping nozzle device 14.
  • the thickness of the flat steel product 100 and the two layers 10 are shown exaggerated in order to be able to show schematically in the spatial area X that the thickness of the layers 10 is reduced by blowing off with the stripping gas AG.
  • the gas jet emerging from the nozzle 14 acts together with gravity (if the flat steel product 100 is pulled vertically upwards from the bath 11, as for example in Fig. 2 and 3 shown) exerts a shearing force on the still liquid layer 10. Due to the shear force, the thickness of the layers 10 is reduced by blowing off with the stripping gas AG.
  • the equations that describe the dynamic flow behavior of the gas AG on the flat steel product 100 are very complex. This is due, among other things, to the fact that in the gas jet that emerges through the nozzle lip gap 17 of the nozzle 15, areas with laminar and turbulent flow patterns form on the layer 10 of the flat steel product 100. In addition, the gas jet sucks in ambient air, which is swirled with the stripping gas AG (which is why it may not be necessary to add water vapor gas WG to the dry gas TG if the ambient air humidity f UG is high).
  • a stripping gas stream AG is generated which contains a very small but sufficiently high amount of water vapor in order to avoid the formation of surface defects and defects in the layers 10.
  • the device 150 and the method work particularly reliably within these (value) ranges.
  • a corresponding gas nozzle 15 has a length (called nozzle width) perpendicular to the plane of the drawing Figures 2 , 3 and 4 (parallel to the z-axis in Fig. 4 ).
  • the nozzle 15 preferably has an active nozzle width that corresponds at least to the bandwidth of the strip-shaped flat steel product 100.
  • the bandwidth of the strip-shaped flat steel product 100 can be, for example, in the range from 500 to 2500 mm, preferably between 800 and 1800 mm and particularly preferably in the range from 1159 mm to 1614 mm.
  • the active nozzle width also increases accordingly.
  • the nozzles are positioned at a variable vertical distance from the zinc bath surface. This distance is commonly referred to as the nozzle height. This distance is set primarily depending on the speed of the belt passing through and/or the zinc layer coating to be adjusted.
  • the nozzle height can be between 230 and 500mm in all embodiments, for example.
  • All embodiments of the device 150 may include an optional controller 250, as in Fig. 3 indicated schematically and by way of example.
  • this controller 250 can be designed as a computer-based automation and control unit and can include a human-machine interface, a computer and a database.
  • the controller 250 if present, can be connected to the means or devices for determining gas moisture 20 via communication connections KV1, KV2.
  • the controller 250 can be part of the overall system control of the device 150 in all embodiments, or it can be connected to the overall system control in all embodiments.
  • the controller 250 can in all embodiments have one or more analog and/or digital inputs to provide information about the currently prevailing environmental conditions (e.g. the current air temperature T L and/or the (absolute) humidity f UG of the environment or the close range). Based on this information, the controller 250 can, for example, reduce or increase (or even switch off) the addition of the water vapor gas stream WG in order to continue to produce layers 10 with trouble-free surfaces in the device 150.
  • the controller 250 can, for example, reduce or increase (or even switch off) the addition of the water vapor gas stream WG in order to continue to produce layers 10 with trouble-free surfaces in the device 150.
  • the controller 250 may include communication links that allow the controller 250 to reduce or increase the flow of the water vapor gas stream WG and/or reduce or increase the flow of the dry gas stream TG.
  • the controller 250 can adapt a mixing valve in the area of the merging 19 of the two gas streams TG, WG to the situation via communication connections, for example.
  • the suction of dry ambient air can lead to the formation of marbling on layer 10. This is where the invention can come into play by switching on or automatically increasing the moisture content in the stripping gas AG.
  • a cold-rolled flat steel product 100 in strip form namely cold-rolled deep-drawing steel in strip form, is cleaned of rolling oil and rolling debris in a pretreatment in the continuous hot-dip coating system by means of a combined dipping/brushing/electrolytic cleaning and rinsed with water in at least some of the embodiments and dried.
  • the cleaned, dried flat steel product 100 in strip form enters an annealing furnace of the continuous hot-dip coating system, where it is preheated by means of a directly fired furnace (DFF) heated and brought to an annealing temperature of 820°C in a radiant tube furnace under protective gas at a dew point of -40°C.
  • DFF directly fired furnace
  • the flat steel product 100 in strip form is cooled to the strip immersion temperature of 450 ° C and immersed in the 430 ° C warm ZnMgAl alloy melt pool 11 for 3s.
  • the flat steel product 100 in strip form is applied to the stripping nozzles 15 of the stripping nozzle device 14 with dry stripping gas AG with a dew point of minus 73 ° C or 3 ppm HzO content to a predetermined target layer thickness of ZM90 (45 g/m 2 per side V, R).
  • the stripping nozzles 15 have a nozzle lip gap of 1.0 mm (called the height of the nozzle opening) and are at a horizontal distance (parallel to the y-axis of the Fig. 4 ) of 6 mm on both sides to the flat steel product 100 positioned in strip form.
  • a connected cooling tower 16 see Fig. 1
  • the zinc alloy melt is solidified on the flat steel product 100.
  • the flat steel product 100 is then re-rolled in strip form in a skin pass stand and a roughness of 1.4 ⁇ m is imprinted.
  • the flat steel product 100 in strip form is coated with corrosion protection and forming oil in an oiling machine with 1.0 g/m 2 per side V, R and finally wound up on the reel .
  • the flat steel product 100 can be unwound in strip form, the defective area can be eliminated and the strip can then be wound up again.
  • a cold-rolled flat steel product 100 in strip form namely a cold-rolled deep-drawing steel in strip form, is cleaned of rolling oil and rolling abrasion as part of an in-line pretreatment of the continuous hot-dip coating system by means of a combined dipping/brushing/electrolytic cleaning, rinsed with water and dried.
  • the cleaned, dried flat steel product 100 in strip form enters an annealing oven of the continuous hot-dip coating system, is preheated, heated using a directly fired oven (DFF) and in the radiant tube oven under inert gas at a dew point of -40°C to the annealing temperature of 820°C brought.
  • DFF directly fired oven
  • the flat steel product 100 in strip form is cooled to the strip immersion temperature of the ZnMgAl alloy melt bath 11 of 450 ° C and immersed in the 430 ° C warm ZnMgAl alloy bath 11 for 3s.
  • the flat steel product 100 in strip form is applied to the stripping nozzles 15 with moistened nitrogen (after adding gaseous HzO vapor, as described and claimed here, to 310 ppm or -35 ° C dew point) the target layer thickness of ZM90 (45 g/m 2 per side).
  • the stripping nozzles 15 have a nozzle lip gap of 1.0 mm (height of the nozzle opening) and are at a horizontal distance (parallel to the y-axis of the Fig. 4 ) positioned 6 mm on both sides of the flat steel product 100.
  • a connected cooling tower 16 see Fig. 1
  • the zinc alloy melt is solidified on the flat steel product 100.
  • the flat steel product 100 is then re-rolled in a skin pass stand and a roughness Ra of 1.4 ⁇ m is imprinted.
  • the flat steel product 100 After inspection for surface defects, during which the presence of marbling is determined, the flat steel product 100 is coated with anti-corrosion and forming oil in-line (in a continuous hot-dip coating system) with an oiling machine at 1.0 g / m 2 per side and finally on the reel wound up.
  • the flat steel product 100 can be unwound in strip form, the defective area can be eliminated and the strip can then be wound up again.
  • a cold-rolled deep-drawing steel in strip form is cleaned of rolling oil and rolling abrasion in-line in the pretreatment of the continuous hot-dip coating system by means of a combined dipping/brushing/electrolytic cleaning, rinsed with water and dried.
  • the cleaned, dried flat steel product 100 in strip form enters an annealing oven of the continuous hot-dip coating system, is preheated, heated using a directly fired oven (DFF) and brought to the annealing temperature of 820°C in the jet tube oven under protective gas at a dew point of -40°C.
  • DFF directly fired oven
  • the flat steel product 100 in strip form is cooled to the strip immersion temperature of the ZnMgAl alloy melt pool 11 of 450 ° C and warmed to 430 ° C for 3s ZnMgAl alloy bath 11 dipped.
  • the flat steel product 100 in strip form is applied to the stripping nozzles 15 with moistened nitrogen (after adding gaseous H 2 O vapor, to 552 ppm or -29 ° C dew point) the target layer thickness of ZM90 (45 g / m 2 per page).
  • the stripping nozzles 15 have a nozzle lip gap of 1.0 mm (height of the nozzle opening) and are at a horizontal distance (parallel to the y-axis of the Fig. 4 ) positioned 6 mm on both sides of the flat steel product 100.
  • a connected cooling tower 16 see Fig. 1
  • the zinc alloy melt is solidified on the flat steel product 100.
  • the flat steel product 100 is then re-rolled in a skin pass stand and a roughness of 1.4 ⁇ m is imposed. After inspection for surface defects, during which neither marbling nor toothpick defects are detected, the flat steel product 100 is coated in-line with an oiling machine with 1.0 g/m 2 per side with anti-corrosion and forming oil and finally wound up on the reel.
  • a higher-strength cold-rolled flat steel product 100 in strip form is cleaned of rolling oil and rolling abrasion in the pretreatment of the continuous hot-dip coating system by means of a combined dipping/brushing/electrolytic cleaning, rinsed with water and dried.
  • the cleaned, dried flat steel product 100 enters an annealing oven of the continuous hot-dip coating system, is preheated, heated using a directly fired oven (DFF) and brought to the annealing temperature of 800 ° C in the jet tube oven under inert gas at a dew point of -50 ° C.
  • DFF directly fired oven
  • the flat steel product 100 in strip form is cooled to the strip immersion temperature of the ZnMgAl alloy melt bath 11 of 490 ° C and immersed in the 430 ° C warm ZnMgAl alloy bath 11 for 5s.
  • the flat steel product 100 in strip form is applied to the stripping nozzles 15 with moistened nitrogen (after adding gaseous H 2 O vapor, to 3065 ppm or - 9 ° C dew point) the target layer thickness of ZM90 (45 g / m 2 per page).
  • the stripping nozzles 15 have a nozzle lip gap of 1.0 mm (height of the nozzle opening) and are at a horizontal distance (parallel to the y-axis of the Fig. 4 ) of 7.6 mm on both sides to the flat steel product 100 positioned.
  • a connected cooling tower 16 see Fig. 1
  • the zinc alloy melt is solidified on the flat steel product 100.
  • the flat steel product 100 is then re-rolled in a skin pass stand and a roughness of 1.3 ⁇ m is imposed. After inspection for surface defects, during which neither marbling nor toothpick defects are detected, the flat steel product 100 is coated in-line with an oiling machine with 0.8 g/m 2 per side with anti-corrosion and forming oil and finally wound up on the reel.
  • a structural steel is cleaned as a cold-rolled flat steel product 100 in strip form in the pretreatment of the continuous hot-dip coating system by means of a combined dipping/brushing/electrolytic cleaning of rolling oil and rolling abrasion, rinsed with water and dried.
  • the cleaned, dried flat steel product 100 enters an annealing oven of the continuous hot-dip coating system, is preheated, heated using a directly fired oven (DFF) and brought to the annealing temperature of 730 ° C in the jet tube oven under inert gas at a dew point of -45 ° C.
  • DFF directly fired oven
  • the flat steel product 100 in strip form is cooled to the strip immersion temperature of the ZnMgAl alloy melt bath 11 of 465 ° C and immersed in the 455 ° C warm ZnMgAl alloy bath 11 for 4 s.
  • the flat steel product 100 in strip form is applied to the stripping nozzles 15 with dry nitrogen (without admixing gaseous H 2 O vapor; 3ppm or -75 ° C dew point) to the target layer thickness of ZM120 (60 g / m 2 per page).
  • the stripping nozzles 15 have a nozzle lip gap of 1.0 mm (called the height of the nozzle opening) and are at a horizontal distance (parallel to the y-axis of the Fig. 4 ) of 7.7 mm on both sides to the flat steel product 100 positioned.
  • a connected cooling tower 16 see Fig. 1
  • the zinc alloy melt is solidified on the flat steel product 100.
  • the flat steel product 100 is then made flat in a bending-stretching machine and re-rolled in a skin pass stand and a roughness of 1.4 ⁇ m is imposed. After inspecting for surface defects, neither If marbling or toothpick defects are found, the flat steel product 100 is wound up on the reel.
  • the steel strip 100 is then coated with a lacquer in a continuous strip coating system.
  • a structural steel is cleaned as a cold-rolled flat steel product 100 in strip form in the pretreatment of a continuous hot-dip coating system by means of a combined dipping/brushing/electrolytic cleaning of rolling oil and rolling abrasion, rinsed with water and dried.
  • the cleaned, dried flat steel product 100 in strip form enters an annealing furnace of the continuous hot-dip coating system, is preheated, heated using a directly fired furnace (DFF) and brought to the annealing temperature of 730°C in the jet tube furnace under protective gas at a dew point of -45°C.
  • DFF directly fired furnace
  • the flat steel product 100 in strip form is cooled to the strip immersion temperature of the ZnMgAl alloy melt bath 11 of 465 ° C and immersed in the 455 ° C warm ZnMgAl alloy bath 11 for 4 s.
  • the flat steel product 100 in strip form is applied to the stripping nozzles 15 with moistened nitrogen (after adding gaseous H 2 O vapor to 1470 ppm or -18 ° C dew point) the target layer thickness of ZM120 (60 g / m 2 per page).
  • the stripping nozzles 15 have a nozzle lip gap of 1.0 mm (called the height of the nozzle opening) and are at a horizontal distance (parallel to the y-axis of the Fig. 4 ) of 7.7 mm on both sides to the flat steel product 100 positioned.
  • a connected cooling tower 16 see Fig. 1
  • the zinc alloy melt is solidified on the flat steel product 100.
  • the flat steel product 100 is then flattened in a bending-stretching machine and re-rolled in a skin pass stand, imparting a roughness of 1.4 ⁇ m. After inspection for surface defects, in which neither marbling nor toothpick defects are detected, the flat steel product 100 is wound up on the reel.
  • the steel strip 100 is then coated with a lacquer in a continuous strip coating system.
  • a structural steel is used as a cold-rolled flat steel product 100 in strip form in the pretreatment of a continuous Hot-dip coating system cleaned of rolling oil and rolling debris using a combined dipping/brushing/electrolytic cleaning, rinsed with water and dried.
  • the cleaned, dried flat steel product 100 enters an annealing oven of the continuous hot-dip coating system, is preheated, heated using a directly fired oven (DFF) and brought to the annealing temperature of 730 ° C in the jet tube oven under inert gas at a dew point of -45 ° C.
  • DFF directly fired oven
  • the flat steel product 100 in strip form is cooled to the strip immersion temperature of the ZnMgAl alloy melt bath 11 of 465 ° C and immersed in the 455 ° C warm ZnMgAl alloy bath 11 for 4 s.
  • the flat steel product 100 in strip form is applied to the stripping nozzles 15 with moistened nitrogen (after adding gaseous H 2 O vapor to 5230 ppm or - 2 ° C dew point) the target layer thickness of ZM120 (60 g / m 2 per page).
  • the stripping nozzles 15 have a nozzle lip gap of 1.0 mm (height of the nozzle opening) and are at a horizontal distance (parallel to the y-axis of the Fig. 4 ) of 7.7 mm on both sides to the flat steel product 100 positioned.
  • a connected cooling tower 16 see Fig. 1
  • the zinc alloy melt is solidified on the flat steel product 100.
  • the flat steel product 100 is then flattened in a bending-stretching machine and re-rolled in a skin pass stand, imparting a roughness of 1.4 ⁇ m. After inspecting for surface defects in which neither marbling nor toothpick defects are detected, the steel strip 100 is wound up on the reel.
  • the steel strip 100 is then coated with a lacquer in a continuous strip coating system.
  • a mild steel is cleaned as a cold-rolled flat steel product 100 in strip form in the pretreatment of a continuous hot-dip coating system by means of a combined dipping/brushing/electrolytic cleaning of rolling oil and rolling abrasion, rinsed with water and dried.
  • the cleaned, dried flat steel product 100 in strip form enters an annealing oven of the continuous hot-dip coating system, is preheated, heated using a directly fired oven (DFF) and placed in the jet tube oven under protective gas at a dew point of -50 ° C Annealing temperature of 720 ° C brought.
  • DFF directly fired oven
  • the flat steel product 100 in strip form is cooled to the strip immersion temperature of the ZnMgAl alloy melt bath 11 of 460 ° C and immersed in the 455 ° C warm ZnMgAl alloy bath 11 for 3s.
  • the flat steel product 100 in strip form is applied to the stripping nozzles 15 with dry nitrogen (without admixing gaseous H 2 O vapor; 3ppm or - 74 ° C dew point) to the target layer thickness of ZM90 (45 g / m 2 per page).
  • the stripping nozzles 15 have a nozzle lip gap of 1.2 mm (called the height of the nozzle opening) and are at a horizontal distance (parallel to the y-axis of the Fig. 4 ) positioned 10 mm on both sides of the flat steel product 100.
  • a connected cooling tower 16 see Fig. 1
  • the zinc alloy melt is solidified on the flat steel product 100.
  • the flat steel product 100 is then made flat in a bending-stretching machine and re-rolled in a skin pass stand, thereby imparting a roughness of 1.0 ⁇ m.
  • an organic/inorganic passivation layer is applied using a coater (coating device) and dried.
  • the steel strip 100 After inspecting for surface defects, which reveals marbling and toothpick defects, the steel strip 100 is wound on the reel. In a further step, for example in a so-called inspection line, the flat steel product 100 can be unwound in strip form, the defective area can be eliminated and the strip can then be wound up again.
  • a mild steel is cleaned as a cold-rolled flat steel product 100 in strip form in the pretreatment of a continuous hot-dip coating system by means of a combined dipping/brushing/electrolytic cleaning of rolling oil and rolling abrasion, rinsed with water and dried.
  • the cleaned, dried flat steel product 100 enters an annealing oven of the continuous hot-dip coating system, is preheated, heated using a directly fired oven (DFF) and brought to the annealing temperature of 760 ° C in the jet tube oven under inert gas at a dew point of -50 ° C.
  • DFF directly fired oven
  • the flat steel product 100 in strip form is brought to the strip immersion temperature of the ZnMgAl alloy melt pool 11 cooled from 460 ° C and immersed in the 455 ° C warm ZnMgAl alloy bath 11 for 4s.
  • the flat steel product 100 in strip form is applied to the stripping nozzles 15 with moistened nitrogen (after adding gaseous HzO vapor to 9980 ppm or + 7 ° C dew point) the target layer thickness of, for example, ZM120 (60 g / m 2 per side ) set.
  • the stripping nozzles 15 have a nozzle lip gap of 1.2 mm (called the height of the nozzle opening) and are at a horizontal distance (parallel to the y-axis of the Fig. 4 ) positioned 10 mm on both sides of the flat steel product 100.
  • a connected cooling tower 16 see Fig. 1
  • the zinc alloy melt is solidified on the flat steel product 100.
  • the flat steel product 100 is then made flat in a bending-stretching machine. After inspection for surface defects, in which neither marbling nor toothpick defects are detected, the steel strip 100 is wound up on the reel.
  • the steel strip 100 is then coated with a lacquer in a continuous strip coating system.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Computer Hardware Design (AREA)
  • Coating With Molten Metal (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
EP23164714.0A 2022-06-30 2023-03-28 Dispositif et procédé pour un soufflage sous humidité controlée après l'application d'une couche sur un produit plat en acier Pending EP4299785A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP22182311.5A EP4299784A1 (fr) 2022-06-30 2022-06-30 Procédé et dispositif d'application d'une couche sur un produit plat en acier
EP22182309.9A EP4299783A1 (fr) 2022-06-30 2022-06-30 Dispositif et procédé d'application d'une couche sur un produit plat en acier

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EP4299785A1 true EP4299785A1 (fr) 2024-01-03

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1521405A1 (de) 1951-01-28 1969-08-21 Nat Steel Corp Verfahren zur Herstellung von UEberzuegen
DE2033847A1 (en) 1970-07-02 1972-01-05 Thyssen Huette Ag Galvanised strip prodn - using slotted nozzle for layer thickness control
DE2709551A1 (de) * 1977-03-04 1978-09-07 Inland Steel Co Mit zink-aluminium-legierungen beschichtete eisenmetallgegenstaende sowie mittel und verfahren zu ihrer herstellung
EP0172682A1 (fr) * 1984-07-30 1986-02-26 Armco Inc. Procédé pour contrôler la vapeur de zinc dans un procédé de finition lors d'un procédé de galvanisation de bandes d'acier
DE3933244C1 (en) * 1989-10-05 1990-06-13 Hoesch Stahl Ag, 4600 Dortmund, De Continuous zinc coating appts. for coating metal strip - comprises melt alloy bath covered with hood having hydrogen, steam and inert gas atmos. and control system
JP2008256208A (ja) 2007-03-30 2008-10-23 Volvo Construction Equipment Ab 建設装備用油圧回路
WO2014033153A1 (fr) 2012-09-03 2014-03-06 Voestalpine Stahl Gmbh Procédé de dépôt d'un revêtement protecteur sur un produit plat en acier et produit plat en acier doté d'un revêtement protecteur correspondant
JP2020100886A (ja) 2018-12-25 2020-07-02 日本製鉄株式会社 連続溶融金属めっき方法及び連続溶融金属めっき装置

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1521405A1 (de) 1951-01-28 1969-08-21 Nat Steel Corp Verfahren zur Herstellung von UEberzuegen
DE2033847A1 (en) 1970-07-02 1972-01-05 Thyssen Huette Ag Galvanised strip prodn - using slotted nozzle for layer thickness control
DE2709551A1 (de) * 1977-03-04 1978-09-07 Inland Steel Co Mit zink-aluminium-legierungen beschichtete eisenmetallgegenstaende sowie mittel und verfahren zu ihrer herstellung
EP0172682A1 (fr) * 1984-07-30 1986-02-26 Armco Inc. Procédé pour contrôler la vapeur de zinc dans un procédé de finition lors d'un procédé de galvanisation de bandes d'acier
EP0172682B1 (fr) 1984-07-30 1989-02-01 Armco Inc. Procédé pour contrôler la vapeur de zinc dans un procédé de finition lors d'un procédé de galvanisation de bandes d'acier
DE3933244C1 (en) * 1989-10-05 1990-06-13 Hoesch Stahl Ag, 4600 Dortmund, De Continuous zinc coating appts. for coating metal strip - comprises melt alloy bath covered with hood having hydrogen, steam and inert gas atmos. and control system
JP2008256208A (ja) 2007-03-30 2008-10-23 Volvo Construction Equipment Ab 建設装備用油圧回路
WO2014033153A1 (fr) 2012-09-03 2014-03-06 Voestalpine Stahl Gmbh Procédé de dépôt d'un revêtement protecteur sur un produit plat en acier et produit plat en acier doté d'un revêtement protecteur correspondant
JP2020100886A (ja) 2018-12-25 2020-07-02 日本製鉄株式会社 連続溶融金属めっき方法及び連続溶融金属めっき装置

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
C.V. TUD.H. WOOD: "Wall Pressure and Shear Stress Measurements Beneath an Impinging Jet", EXPERIMENTAL THERMAL AND FLUID SCIENCE, vol. 13, November 1996 (1996-11-01), pages 364 - 373
M. DUBOIS: "AISTech 2019-Proceedings of the Iron & Steel Conference", 2019, ASSOCIATION FOR IRON & STEEL TECHNOLOGY, article "Minimization of the N2 Dilution When Wiping in Air"

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