US20220213574A1 - Processing line for the continuous processing of metal strips having a dual purpose of producing strips that are annealed and dip-coated or not coated, and corresponding cooling tower and method for switching from one configuration to the other - Google Patents

Processing line for the continuous processing of metal strips having a dual purpose of producing strips that are annealed and dip-coated or not coated, and corresponding cooling tower and method for switching from one configuration to the other Download PDF

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US20220213574A1
US20220213574A1 US17/606,363 US202017606363A US2022213574A1 US 20220213574 A1 US20220213574 A1 US 20220213574A1 US 202017606363 A US202017606363 A US 202017606363A US 2022213574 A1 US2022213574 A1 US 2022213574A1
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cooling
configuration
strips
coated
annealed
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Michel Clin
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Fives Stein SA
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Fives Stein SA
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C21D9/573—Continuous furnaces for strip or wire with cooling
    • C21D9/5735—Details
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0273—Final recrystallisation annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/62—Quenching devices
    • C21D1/63—Quenching devices for bath quenching
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/68—Temporary coatings or embedding materials applied before or during heat treatment
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/0062—Heat-treating apparatus with a cooling or quenching zone
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C21D9/561—Continuous furnaces for strip or wire with a controlled atmosphere or vacuum
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C21D9/573—Continuous furnaces for strip or wire with cooling
    • 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
    • C23C2/0034—Details related to elements immersed in bath
    • C23C2/00342—Moving elements, e.g. pumps or mixers
    • C23C2/00344—Means for moving substrates, e.g. immersed rollers or immersed bearings
    • 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
    • C23C2/0035—Means for continuously moving substrate through, into or out of the bath
    • 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
    • C23C2/0038—Apparatus characterised by the pre-treatment chambers located immediately upstream of the bath or occurring locally before the dipping process
    • 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
    • C23C2/0038—Apparatus characterised by the pre-treatment chambers located immediately upstream of the bath or occurring locally before the dipping process
    • C23C2/004—Snouts
    • 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
    • C23C2/26—After-treatment
    • C23C2/261—After-treatment in a gas atmosphere, e.g. inert or reducing atmosphere
    • 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
    • C23C2/26—After-treatment
    • C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
    • 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
    • C23C2/26—After-treatment
    • C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
    • C23C2/29—Cooling or quenching
    • 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
    • C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
    • C23C2/36—Elongated material
    • C23C2/40—Plates; Strips

Definitions

  • the invention relates to the field of production lines for coils of metal strips having a dual purpose of producing either strips that are annealed and dip-coated or strips that are annealed only, that is to say, uncoated.
  • the coating can be of any type, based on zinc, aluminum, a mixture of zinc and aluminum, or any other component. More specifically, the invention relates to devices and methods that make it possible to give a line a dual purpose, with an operation in annealing-only mode or in annealing, then coating mode, with easy switching from one operating mode to the other.
  • the steel strip is generally cooled to a temperature below 200° C., typically of approximately 150° C., in a cooling section, before it leaves the furnace, in order to avoid the problems of oxidation of the strip in the open air that would result from leaving the strip at too high a temperature.
  • the final cooling section refers to the cooling section that has just been described.
  • the strip In the coated mode, it is necessary to bring the strip to a temperature close to that of the coating bath before it is immersed therein. This temperature varies according to the type of coating produced. It is for example 460° C. for galvanizing, but it is always much higher than the temperature of 150° C. targeted at the end of cooling in annealing mode.
  • the strip On leaving the coating bath, the strip is in the open air. It can then undergo a heat treatment modifying the quality of the coating (galvannealing) before a step of air cooling followed by water cooling to bring it to a temperature close to ambient temperature.
  • the final cooling section refers to the last cooling section upstream of the coating bath, in the direction of travel of the strip.
  • the design of the final cooling section of an annealing line does not make it possible to prolong the maintenance of the strip at temperature before starting the cooling.
  • the start of cooling of the strip necessarily begins as soon as the latter enters the final cooling section.
  • the cooling rate of the strip is imposed by the concerned metallurgical structure.
  • the cooling of the strip can be completed long before the end of the final cooling section.
  • the end of the final cooling section When in coating mode, it may then be necessary to keep the end of the final cooling section at a sufficient temperature before the strip enters the coating bath, for example at 460° C. Indeed, if the strip is too cold when it arrives in the coating bath, the bath will cool (since the power that can be installed on a coating tank is limited) and will therefore generate mattes that will cause problems with the coating quality or with the management of the temperature of the bath. In addition, by being kept at temperature, the final cooling section increases the hold time. The final cooling section must therefore comprise heating means allowing this.
  • the present invention provides a solution to the problem of using the same equipment, the final cooling section when it is present, in annealing mode and in coated mode.
  • the present invention also minimizes problems caused by the presence of said final cooling section, which is always necessary in annealing mode, but which is not necessary in certain configurations in coated mode.
  • CAL mode to denote an operation of the line in annealing mode only, without metallic coating during quenching
  • CGL mode to denote an operation of the line in annealing and coating mode during quenching, independent of the nature of the coating.
  • CAL is the acronym commonly used to denote an annealing line (for “Continuous Annealing Line”)
  • CGL is the acronym used to designate a galvanizing line (for “Continuous Galvanizing Line”).
  • Document JP2004346359 is known, which discloses a cooling tower used in a non-oxidizing atmosphere. The document does not disclose a cooling section designed to operate with both line configurations, that is to say, also in air.
  • Document EP0072874 describes an installation with a dual configuration for manufacturing cold-rolled steel sheets and hot-coated galvanized steel sheets, which comprises, arranged successively in series, a heating zone, an equalization zone, a primary cooling zone, an overaging zone, with the possibility of controlled cooling, hot-dip galvanizing means, intermediate cooling means, a secondary cooling zone, hardening rolling means, and chemical treatment means.
  • the strip does not pass through the cooling tower, which is circumvented by means of a bypass to directly connect the overaging zone and the secondary cooling zone.
  • EP3181709 describes a solution allowing the switch from a CGL mode to a CAL mode and vice versa. It mainly consists in having devices placed at the exit from the furnace, upstream of the coating bath, to ensure the sealing of the furnace in CAL mode, when the bath is removed and the bottom roll of the bath is replaced, instead, by a deflector roll.
  • This solution does not address the technical problems mentioned above, since the final cooling section of the furnace must be dimensioned to allow cooling of the strip to approximately 150° C. in CAL mode.
  • EP1325163 describes a combined steel treatment line with a bypass installation for the coating zone and the cooling tower allowing the switch from a CGL mode to a CAL mode and vice versa.
  • the bypass installation makes it possible to transfer the strip from the annealing furnace to the water tank placed at the outlet of the cooling tower without it being exposed to the ambient air.
  • the bypass installation is placed above the galvanizing pot and the bath area equipment. This solution is not fully satisfactory, in particular because it complicates the arrangement of the line and it does not make it possible to benefit from the air cooling means of the cooling tower in annealing mode.
  • the invention makes it possible to address these technical problems with a dual-use CAL/CGL line that does not significantly modify the thermal cycle of the steel grade targeted in CAL mode and in CGL mode, while allowing optimized use of the cooling equipment.
  • These two aspects are obtained by allowing the cooling equipment installed in the cooling tower to operate in different modes, oxidizing or reducing for the strip depending on the coolant used, allowing the capacity of the final cooling section in the furnace to be reduced, or even allowing it to be eliminated.
  • a cooling tower for a continuous treatment line for metal strips having a dual purpose, which has a configuration for producing strips that are annealed and dip-coated and a configuration for producing strips that are annealed and not coated.
  • the tower according to the first aspect of the invention is designed to operate in both line configurations. It comprises blowing means for cooling the strip selectively under a non-oxidizing atmosphere in the configuration for uncoated annealed strips and under air in the configuration for annealed and coated strips.
  • the tower according to the first aspect of the invention can further comprise cooling sections connected together to form a sealed cooling tunnel.
  • the sealed cooling tunnel may further be formed by connecting tunnels interposed between two cooling sections and/or other elements.
  • the sealed tunnel can extend only on the rising strand, or on the rising strand and on the descending strand.
  • the tower according to the first aspect of the invention may further comprise, in the direction of travel of the strip, in the configuration for producing uncoated annealed strips, means for sampling a non-oxidizing atmosphere present at the strip upstream of the blowing means, means for recirculating and cooling said sampled atmosphere, the blowing means being arranged to blow the sampled, cooled and recirculated atmosphere.
  • a continuous treatment line for metal strips having a dual purpose, which has a configuration for producing strips that are annealed and dip-coated and a configuration for producing strips that are annealed and not coated.
  • the line comprises, successively in the direction of travel of the strip, an immersion tunnel, a bath area provided with equipment in said configuration for producing strips that are annealed and dip-coated in a metal alloy, and a cooling tower having a rising strand and a descending strand.
  • the bath area is removable and can be replaced by a box designed to provide a sealed fluid connection between the immersion tunnel and the cooling tower.
  • the cooling line according to the third aspect of the invention does not have a final cooling section.
  • a method for switching from one configuration to another of a treatment line for the continuous treatment of metal strips having a dual comprising the steps of the method for switching from said configuration to said other configuration of a cooling tower according to the second aspect of the invention, or one or more of its improvements, and further comprising the following steps:
  • FIG. 1 is a schematic view of a dual-use CAL and CGL line, in CGL mode, according to the state of the art
  • FIG. 2 is a schematic view of the end of a dual-use CAL and CGL line, in CGL mode according to one embodiment of the invention
  • FIG. 3 is a schematic view of the end of the dual-use CAL and CGL line of FIG. 2 , but in CAL mode,
  • FIG. 4 is a schematic view of the end of a dual-use CAL and CGL line, in CGL mode according to a second embodiment of the invention
  • FIG. 5 is a schematic view of the end of the dual-use CAL and CGL line of FIG. 4 , but in CAL mode,
  • FIG. 7 is a schematic view of a cooling section, in top view, according to another embodiment of the invention.
  • FIG. 8 is a schematic view of the end of a dual-use CAL and CGL line, in CGL mode according to another embodiment of the invention.
  • variants of the invention comprise only a selection of the features that are described, provided that this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art.
  • This selection comprises at least one preferably functional feature without structural details, or with only a portion of the structural details if this portion alone is sufficient to confer a technical advantage or to differentiate the invention from the prior art.
  • FIG. 1 schematically shows a portion of an annealing and galvanizing line according to the state of the art. It is shown in CGL mode, the devices that allow switching to CAL mode not being shown.
  • mechanical equipment located at the line inlet such as unwinders, welder, accumulator, etc.
  • that placed at the line outlet such as accumulator, shears, rewinders, etc.
  • installation equipment that is not useful for understanding the invention is neither described nor shown in the drawings, such as surface preparation equipment (stripping, degreasing, rinsing, etc.) placed upstream of the furnace, or a phosphating section placed at the exit from the furnace.
  • the heating, maintaining and cooling sections are represented very schematically in the drawings by rectangles. They may comprise several chambers, each of which may have different heating or cooling means, for example with heating by direct flames, by radiation or by induction and cooling by blowing a cooling gas, by spraying a liquid that may or may not be oxidizing, or by using a mixture of gas and liquid. Finally, most of the equipment necessary for conveying the strip is neither described nor shown, such as deflector rollers, strip traction rollers, strip guide rollers, etc.
  • the line portion shown in FIG. 1 comprises, in the direction of travel of the strip:
  • FIG. 2 One embodiment of the invention is shown schematically in FIG. 2 , the line being in CGL mode.
  • the capacity of this line is identical to that of the line shown in FIG. 1 , in particular in terms of the maximum running speed of the strip and of the reference format for the strip.
  • the overaging section 6 is similar to that of FIG. 1 , that is to say, for a given strip format, it allows the same residence time of the strip at the same maintenance temperature.
  • the final cooling section 7 is greatly reduced compared to the state of the art, only one strip pass being retained.
  • strip pass the present description refers to a vertical path of the strip, here from the bottom to the top.
  • the final cooling section 7 may be absent, the cooling of the strip being carried out only in the cooling tower, and, if necessary, downstream thereof.
  • the cooling tower 14 comprises means on the rising strand for cooling the rising strand.
  • Each of the cooling means may be a cooling section 30 , as shown in FIG. 2 .
  • the four cooling sections 30 can be sealingly connected to one another so as to obtain a sealed cooling tunnel 31 .
  • the cooling means can comprise other cooling means.
  • the cooling sections 30 can be arranged on the lower part of the rising strand, the other cooling means being on the upper part.
  • the cooling sections 30 can be connected to one another in a sealed manner by means of connecting tunnels 38 (not shown) interposed between two cooling sections.
  • the connecting tunnels interposed between two cooling sections also make up the sealed cooling tunnel 31 .
  • a plenum 40 supplies gas to the cooling sections 30 .
  • a fan 41 is arranged on the connecting pipe between the plenum 40 and a cooling section 30 so as to adjust the cooling capacity of the cooling section separately from the other cooling sections.
  • another flow rate regulator such as a valve, can be installed on this connecting pipe in addition to or as a replacement for the fan 41 .
  • a fan 43 and a heat exchanger 44 are arranged at the intake of the plenum 40 , the latter being in the open air. The heat exchanger makes it possible to keep the cooling gas at the desired temperature at the inlet of the cooling sections by means of a heat transfer fluid, for example water. As we will see below, this exchanger 43 is particularly useful when the line is operating in CAL mode.
  • the coolant that circulates in the plenum 40 , the cooling sections 30 and the sealed cooling tunnel 31 is air. Since the strip is coated, there is no problem of oxidation of the strip.
  • a sealing airlock 13 is connected, directly or indirectly via a connecting tunnel, in a sealed manner to the last cooling section 30 in the direction of travel of the strip. Since this airlock is useful in CAL operation, it will be described below. It can be kept open in CGL mode.
  • the equipment for the bath area is in place.
  • This equipment in particular comprises the tank containing the coating bath 12 , the bath mechanics (in particular a bottom roll 12 a ), and the machine 13 for squeezing the strip at the outlet of the bath.
  • a galvannealing section 15 comprising a heating zone 15 a followed by a holding zone 15 b is placed downstream of the squeezing machine and upstream of the cooling sections 30 . This galvannealing section is removable to be taken offline when not in use.
  • the shoe 11 at the end of the immersion tunnel 10 plunges into the bath and provides a hydraulic seal, preventing the atmosphere of the furnace from escaping.
  • the submerged part of the shoe is “soiled” by residues from the bath. It is thus advantageous to have a removable shoe so as to remove it when switching to CAL mode in order to be connected to the immersion tunnel.
  • FIG. 3 illustrates the line shown in FIG. 2 after it has been modified for operation in CAL mode.
  • the equipment in the bath area has been removed.
  • a box 70 provides a sealed connection and fluid continuity between the immersion tunnel 10 and the first cooling section 30 of the rising strand of the cooling tower 14 , or the galvannealing section 15 if the latter is present because it is not removable. In this case, the galvannealing section must be impermeable.
  • the sealing system 10 a of the immersion tunnel is kept open.
  • the box 70 comprises a deflector roll 71 arranged substantially in place of the bottom roll 12 a of the bath mechanics.
  • the airlock 13 is kept closed in order to limit the gas leakage rate, correspondingly reducing the operating cost of the line.
  • the sealed box 70 and the cooling sections 30 are thus maintained under a protective atmosphere, which does not oxidize the strip, as in the furnace.
  • the intake of the fan 43 is connected to the box 70 by means of a pipe 45 .
  • This protective gas is thus recirculated by being sucked in at the box 70 , led to the plenum 40 via the pipe 45 .
  • the heat exchanger 44 placed at the inlet of the plenum 40 makes it possible to discharge the calories taken from the strip.
  • the recirculated gas is thus brought back to a suitable temperature before again being projected onto the strip.
  • the installation comprises devices, not shown, making it possible to quickly purge the equipment when switching from a CAL to a CGL operating mode and vice versa.
  • Purging makes it possible to replace the air with a non-oxidizing atmosphere, and vice versa, in particular in the immersion tunnel, the box 70 , the cooling sections 30 , the tunnel 31 , the plenum 40 and the connecting pipes.
  • the strip is stopped.
  • the chamber 10 a of the immersion tunnel is closed so as to limit the leakage of the atmosphere from the furnace during line conversion operations.
  • the shoe 11 of the immersion tunnel is removed, and the squeezing machine 13 , the bath mechanics and its bottom roll 12 a and the bath 12 are removed.
  • the galvannealing section 15 is taken offline.
  • the strip is cut.
  • the waterproof box 70 and the deflector roll 71 are installed in place of the bath equipment.
  • the two ends of the strip are welded together.
  • the sealed connections between the box 70 and the immersion tunnel 10 on the one hand, and the first cooling section 30 on the other hand, are made.
  • the connecting pipe 45 is connected to the box 70 and to the intake of the fan 43 .
  • the airlock 13 located at the outlet of the rising strand of the strip in the cooling tower is closed and brought online.
  • the box 70 , the tunnel 31 , the plenum 40 and the connecting pipes are purged with cooling gas until the oxygen content in this equipment drops to the target value.
  • the airlock 10 a of the immersion tunnel is open.
  • the strip is re-energized and set in motion again.
  • the strip is stopped.
  • the airlock 10 a of the immersion tunnel is closed.
  • the airlock 13 located at the outlet of the rising strand of the strip in the cooling tower is open.
  • the cooling gas used in CAL mode is purged with air.
  • the strip is cut and each end of the strip is removed from the box 70 .
  • the connecting pipe 45 between the box 70 and the plenum 40 is disconnected.
  • the sealed box 70 and the deflector roll 71 are moved.
  • the shoe 11 of the immersion tunnel, the bath 12 , the bath mechanics and the squeezing machine 13 are installed.
  • the galvannealing section 15 is brought online.
  • the two ends of the strip are welded together.
  • the shoe 11 is immersed in the bath 12 , the airlock 10 a is open, the strip is energized and then running. Note that the chronology of operations to start production is the same as that used when changing baths and bath equipment.
  • FIG. 4 Another embodiment of the invention is shown schematically in FIG. 4 , the line being in CGL mode.
  • the configuration of the cooling tower 14 is similar to that of FIG. 1 .
  • the fan 44 and the heat exchanger 43 that were placed at the inlet of the plenum 40 in the previous example are replaced by fans 41 and heat exchangers 42 placed on the connecting pipes between the plenum 40 and the cooling sections 30 .
  • the intake of the plenum 40 is in the open air in CGL mode, the valve 63 being open.
  • a second plenum 50 is placed at the outlet of the cooling sections 30 .
  • Each cooling section is connected to the second plenum 50 by a pipe comprising an exhauster 51 .
  • a pipe 60 comprising a valve 62 connects the two plenums 40 and 50 .
  • the vent hole of the plenum 50 is in the open air in CGL mode, the valve 61 being open and the valve 62 being closed so that there is no flow in the pipe 60 .
  • the second plenum 50 collects the cooling gas after exchange with the strip. This is of great interest in CAL mode, as we will see below.
  • FIG. 5 the line shown in FIG. 4 has been configured in CAL mode.
  • the equipment of the bath area has been removed and replaced by the box 70 and its deflector roll 71 .
  • the valve 63 at the intake of the plenum 40 is closed as well as the valve 61 at the vent hole of the plenum 50 .
  • the box 70 and the tunnel 31 are maintained in a non-oxidizing atmosphere.
  • the valve 62 on the pipe 60 is opened so that cooling gas is recirculated.
  • FIG. 7 schematically illustrates another embodiment of the invention comprising a recirculation loop 49 per cooling section 30 .
  • a non-oxidizing gas is recirculated in the circuit 49 by means of a fan 41 , the two valves 46 being open and the two valves 47 , 48 being closed, the exchanger 42 making it possible to discharge the calories extracted from the strip by a heat transfer fluid.
  • the recirculation circuit is closed by means of the two valves 46 ; the two valves 47 and 48 for venting the circuit are open. The strip B is thus cooled with non-recirculated air.
  • a tunnel 36 provides a sealed connection between the cooling sections 30 of the descending strand and those of the rising strand.
  • one or more cooling sections 30 sealingly connected to one another so as to obtain a sealed cooling tunnel 32 are placed on the horizontal connecting strand between the rising strand and the descending strand of the cooling tower.
  • a connecting tunnel 33 connects these cooling sections 30 with those of the rising strand.
  • the descending strand also comprises a set of cooling sections 30 sealingly connected to one another so as to obtain a sealed cooling tunnel 34 .
  • All of the cooling means of the descending strand of the tower can be cooling sections 30 . If not all of them are, the cooling sections 30 are arranged on the upper part of the descending strand, the other units being on the lower part.
  • a tunnel 35 provides a sealed connection between the cooling sections 30 of the descending strand and those of the horizontal connecting strand between the rising strand and the descending strand.
  • the cooling sections 30 are supplied by at least two plenums 40 and the cooling gas is collected by at least two plenums 50 after blowing on the strip.
  • one plenum 40 a serves the cooling sections of the rising strand and a second plenum 40 b serves the cooling sections of the descending strand, any cooling sections of the horizontal strand being connected to the first or to the second plenum.
  • one plenum 50 a collects the cooling gas coming from the cooling sections of the rising strand and a second plenum 50 b collects that coming from the cooling sections of the descending strand, any cooling sections of the horizontal strand being connected to the first or to the second plenum.
  • the fluid used in the cooling sections 30 can be a mixture of a gas and a sprayed liquid, for example water in CGL mode and a non-oxidizing liquid for the strip in CAL mode.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Coating With Molten Metal (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
US17/606,363 2019-04-29 2020-04-28 Processing line for the continuous processing of metal strips having a dual purpose of producing strips that are annealed and dip-coated or not coated, and corresponding cooling tower and method for switching from one configuration to the other Pending US20220213574A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR1904505A FR3095452A1 (fr) 2019-04-29 2019-04-29 Ligne de traitement en continu de bandes métalliques à double usage
FRFR1904505 2019-04-29
PCT/FR2020/050720 WO2020221977A1 (fr) 2019-04-29 2020-04-28 Ligne de traitement en continu de bandes métalliques à double usage de production de bandes recuites et revêtues au trempé ou non revêtues, tour de refroidissement et procédé de passage d'une configuration à l'autre correspondants

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US (1) US20220213574A1 (ko)
EP (1) EP3963116A1 (ko)
JP (1) JP2022532862A (ko)
KR (1) KR20220002536A (ko)
CN (1) CN113811627A (ko)
FR (1) FR3095452A1 (ko)
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US4408561A (en) * 1981-08-24 1983-10-11 Nippon Steel Corporation Dual-purpose plant for producing cold rolled steel sheet and hot-dip galvanized steel sheet
EP0072874B1 (en) * 1981-08-25 1985-05-29 Nippon Steel Corporation Dual-purpose plant for producing cold rolled steel sheet and hot-dip galvanized steel sheet
JP2002088414A (ja) 2000-09-13 2002-03-27 Nippon Steel Corp 連続焼鈍及び溶融メッキ兼用設備
JP4728494B2 (ja) * 2001-03-13 2011-07-20 新日本製鐵株式会社 連続焼鈍および溶融メッキ兼用設備
JP2004346359A (ja) * 2003-05-21 2004-12-09 Nisshin Steel Co Ltd 冷延鋼帯の製造装置および製造方法
BE1017086A3 (fr) * 2006-03-29 2008-02-05 Ct Rech Metallurgiques Asbl Procede de recuit et preparation en continu d'une bande en acier a haute resistance en vue de sa galvanisation au trempe.
JP4427527B2 (ja) * 2006-07-20 2010-03-10 三菱日立製鉄機械株式会社 表面処理鋼板製造設備
JP5058769B2 (ja) * 2007-01-09 2012-10-24 新日本製鐵株式会社 化成処理性に優れた高強度冷延鋼板の製造方法および製造設備
FR2919876B1 (fr) * 2007-08-10 2009-10-09 Siemens Vai Metals Tech Sas Ligne combinee de recuit et de galvanisation et procede de transformation d'une ligne de recuit continu en une telle ligne combinee
DE102008005259B4 (de) * 2008-01-18 2011-12-08 Carl Kramer Verfahren zur Energieeinsparung bei Wärmebehandlungsanlagen mit durch Heizteil und Kühlteil bewegtem Gut
CN201512572U (zh) * 2009-10-22 2010-06-23 中国钢研科技集团有限公司 钢带连续热镀锌及连续退火两用炉
CN201873735U (zh) * 2010-11-24 2011-06-22 佛山市高明基业冷轧钢板有限公司 一种具有连续热镀锌和连续退火功能的机组
WO2013187042A1 (ja) * 2012-06-13 2013-12-19 Ｊｆｅスチール株式会社 鋼帯の連続焼鈍方法および溶融亜鉛めっき鋼帯の製造方法
JP6450109B2 (ja) 2014-08-11 2019-01-09 Ｊｆｅスチール株式会社 鋼帯の製造装置

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WO2020221977A1 (fr) 2020-11-05
EP3963116A1 (fr) 2022-03-09
KR20220002536A (ko) 2022-01-06
CN113811627A (zh) 2021-12-17
JP2022532862A (ja) 2022-07-20

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