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EP4488608A1 - Four de préchauffage pour galvanisation à chaud en continu - Google Patents

Four de préchauffage pour galvanisation à chaud en continu Download PDF

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Publication number
EP4488608A1
EP4488608A1 EP23183522.4A EP23183522A EP4488608A1 EP 4488608 A1 EP4488608 A1 EP 4488608A1 EP 23183522 A EP23183522 A EP 23183522A EP 4488608 A1 EP4488608 A1 EP 4488608A1
Authority
EP
European Patent Office
Prior art keywords
section
fumes
strip
furnace
metal strip
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP23183522.4A
Other languages
German (de)
English (en)
Inventor
Michel Dubois
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
John Cockerill SA
Original Assignee
John Cockerill SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by John Cockerill SA filed Critical John Cockerill SA
Priority to EP23183522.4A priority Critical patent/EP4488608A1/fr
Priority to PCT/EP2024/063768 priority patent/WO2025008106A1/fr
Publication of EP4488608A1 publication Critical patent/EP4488608A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
    • C23C2/003—Apparatus
    • 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
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • 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
    • 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
    • C21D9/60—Continuous furnaces for strip or wire with induction heating
    • 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
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
    • C23C2/0222—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating in a reactive atmosphere, e.g. oxidising 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
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
    • C23C2/0224—Two or more thermal pretreatments
    • 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
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/06—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated
    • F27B9/062—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated electrically heated
    • F27B9/067—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity heated without contact between combustion gases and charge; electrically heated electrically heated heated by induction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/28—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity for treating continuous lengths of work
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/10—Arrangements for using waste heat

Definitions

  • the present invention relates to a heating process used in continuous hot dip coating lines, such as galvanizing lines, of cold rolled steel strips.
  • the invention also concerns the industrial installation for carrying out the heating process.
  • the coating process consisting in dipping a metal strip in a bath of molten metal is well-known and used all over the world, especially in the case of galvanization.
  • the steel strips Before coating, the steel strips have to be heated in a furnace, on the one hand, to reach at least the temperature of the liquid metal and on the other hand, to induce the recrystallization of the cold rolled sheets as well as to reduce the surface oxide that inhibits a good wetting in the bath and an improved adhesion of the coating on the strip.
  • DFF direct fired furnace
  • This technology has however some strict requirements because the flames are in direct contact with the strip and so may oxidize it, as the burners are directly located inside the furnace. Therefore, such a furnace is usually divided in two sections, as illustrated in Figure 1 , where a standard design used by many manufacturers is represented.
  • the first section is the pre-heating zone 3, also named "post-combustion chamber", that is located on the entry side of the furnace.
  • the second section is strictly speaking the direct fired furnace 4, in which the strip 2 is heated before coating.
  • the metal strip 2 running continuously is pre-heated to approximately 200-300°C, with the aid of the exhaust gases 9 from the direct fired furnace in the second section 4.
  • This first section 3 receives some additional air to burn the residual CO and H 2 in order to ensure a complete combustion of the exhaust gases 9 and finally have fumes with about 2 to 5% O 2 at the stack.
  • the gas radiates to the strip 2 and heats it, but the strip 2 should not reach a temperature higher than 300-350°C, and preferably higher than 300°C, due to excess oxygen, in order to avoid its oxidation.
  • the second section 4 uses an under-stoichiometric combustion to reach a wall temperature up to 1250-1350°C for heating the strip 2 before coating. Again, to avoid strip oxidation, the oxygen content of the gas in contact with the steel strip 2 must be low, and typically below 0.1 %, as soon as the temperature of strip 2 is over 250°C. Therefore, in the second section 4, the combustion being done with under-stoichiometry conditions, CO and H 2 in the fumes remain in a range typically between 2 and 6%. Standard target strip temperatures are typically between 620 and 730°C at the outlet of the DFF operating in under-stoichiometric conditions.
  • a direct fired furnace can be horizontal or vertical. Usually vertical implementation is preferred especially for high production rates. It has the advantage to avoid support rolls that need to be water cooled, which in turn induces a significant reduction in thermal efficiency but also induces a risk of scratches on the strip. It is also known that the height of such a furnace from the inlet (or entrance of the strip) to the rolls at the top is between 10 and 30 meters.
  • the two vertical sections 3, 4 are height linked by a horizontal section 5 as illustrated in Figure 1 .
  • the first section 3 corresponds to the upleg, that is the section where the strip 2 is running up
  • the second section 4 corresponds to the downleg, that is the section where the strip 2 is running down.
  • deflecting rolls 7 typically two, as illustrated in Figure 1 , due to layout constraints
  • the horizontal section 5 is a section separated from the first and the second vertical sections 3, 4, that is cooled and operating in non-oxidizing atmosphere. Narrow openings are then provided to let the strip 2 go through.
  • a special by-pass piping 6 is installed between the first and the second vertical sections 3, 4, so that the fumes 9 go from the direct fired furnace 4 to the post-combustion chamber 3.
  • the fumes 9 are then exiting the first section 3 through a duct provided for waste gases at a temperature comprised between 800 and 1000°C (not shown).
  • the three different sections above are connected with narrow sections or airlocks 10 to avoid that the horizontal section 5 reaches a too high temperature.
  • document FR 2 369 349 A discloses the classical technique for a vertical strip heating furnace including vertical direct fired heating chambers, as described above.
  • Document US 11,193,182 B2 discloses a method for heat-treating a metal strip, where the metal strip is continuously pre-heated in a pre-heating zone with the aid of hot inert gas and subsequently undergoes further heat treatment in a direct fired furnace in a reducing and/or oxidizing atmosphere.
  • This document proposes a solution consisting in the use of an induction heating provided before entry in the DFF.
  • the induction heating is provided in a supplementary vertical section located between the pre-heating zone and the DFF section.
  • This installation requires substantial modifications with respect to existing lines, as hot waste gases produced in the DFF section exchange heat in a heat recovery system comprising two successive heat exchangers and a boiler.
  • the second heat exchanger heats the inert gas used for pre-heating the pre-heating zone of the furnace. At no time there is direct contact of the strip in the pre-heating section with hot waste gases.
  • the present invention aims to provide a solution intended to overcome the drawbacks of prior art.
  • the invention aims to improve the productivity of a line containing a furnace, while keeping mostly unchanged the design of an existing system for hot-dip coating including an annealing furnace, particularly the pass line of the strip therein.
  • a further goal of the present invention is to increase the line productivity and consequently to decrease its cost, especially in the case of producing strips having a thickness greater than 2mm, for example 6mm.
  • the invention aims at providing very reactive heating in an existing standard furnace while requiring minimal modifications of an existing line, essentially without increasing the total furnace height.
  • the present invention relates also in particular to an improvement of the heating capacity while keeping the existing furnace length as well as the constraints related with gas composition necessary to avoid strip oxidation.
  • a first aspect of the present invention relates to an industrial installation for continuous hot dip coating, such as a galvanizing installation, comprising, upstream of a molten metal bath, a furnace having :
  • the installation is further limited by at least one of the following characteristics or a suitable combination thereof:
  • Another aspect of the present invention relates to a method for improving the line productivity in a continuous hot dip coating installation, comprising an installation with a furnace according with the features described above, wherein the method presents at least the following successive steps:
  • the method is further limited by at least one of the following characteristics or a suitable combination thereof:
  • the present invention relates to a continuous hot dip coating installation 1 such as a galvanizing installation, as illustrated in Figures 2A and 2B , comprising an electric heating system 11, such as an induction heating, which is located in a specific manner, either vertical or horizontal. Indeed, the choice of the location of this electric system 11 depends on several parameters. As explained above, the invention aims at taking advantage of e.g. using induction heating in an existing standard furnace with minimal modifications of the existing line and without increasing the total furnace height.
  • the galvanizing installation successively comprises a first section 3 and a second section 4, linked by an intermediary section 5 which is perpendicular to the first and the second sections 3, 4.
  • These three sections 3, 4, 5 are separated by sealing means 10, allowing to keep separate different atmospheres and temperatures in each section.
  • the first and the second sections 3, 4 are vertical and the intermediary section 5 is horizontal.
  • the strip 2 is pre-heated until maximum 350°C, preferably between 250 and 300°C, using hot fumes extracted from section 4 in order to recover as much heat as possible.
  • the intermediary section 5, located between the first section 3 and the second section 4, comprises at least two deflector rolls 7 to change the direction of the running strip 2.
  • the deflector rolls 7 define a pass line for the travelling strip and intermediary section 5 is the pass chamber.
  • the intermediary section 5 is a L-shaped box comprising two legs, a first leg 51 in the prolongation of the first section 3 and a second leg 52, which is perpendicular to the first leg 51.
  • the first leg 51 is vertical and the second leg 52 is horizontal.
  • the first leg 51 comprises the electric heating system 11.
  • the electric heating system has preferably a power of minimum 1MW. It allows to heat the pre-heated metal strip 2 until maximum 700°C, preferably between 400°C-600°C.
  • the intermediary section 5 is a horizontal box perpendicular to the first and the second sections 3, 4, just like in prior art.
  • the electric heating 11 is integrated in the horizontal box between the two deflector rolls 7.
  • the second section 4 comprises a direct fired furnace to heat the steel strip 2 before performing the coating.
  • this second section 4 is vertical.
  • the strip 2 is heated until 780°C but preferably between 620°C and 730°C.
  • the heating is realized with under-stoichiometric conditions in order to avoid oxidizing of the steel strip 2.
  • the installation 1 comprises a fumes pipe 6 between the direct fired furnace of the second section 4 and the top of the first section 3.
  • the first section 3 is heated with the aid of the exhaust gases 9 which are extracted/deflected from the direct fired furnace to obtain a post combustion of the fumes to pre-heat the metal strip 2.
  • the first section 3 can advantageously receive some additional air (not shown) to burn residual CO and H2 in the furnace so that to ensure a complete combustion of the exhaust gases 9.
  • the fumes contain about 2 to 5% O 2 .
  • the gas radiates to the strip 2 to heat it, but the strip 2 cannot reach a temperature higher than 300-350°C (preferably below 300°C) due to the excess oxygen, in order to avoid its oxidation.
  • the installation 1 comprises a narrow path 12 to inject some N 2 (or similar oxygen-free gas like for example fumes from the furnace that will be cooled in the top of the first section 3) at the location of the sealing means 10, in order to counterbalance the buoyancy effect of the fumes 9.
  • N 2 can also be injected from the intermediate section 5 to the second section 4 at the location of the sealing means 10, in order to prevent contamination of the non-oxidizing intermediate section 5 by the fumes generated by combustion in the direct fired furnace.
  • induction heating using the longitudinal flux technology is suitable especially when the total length of the furnace is defined.
  • the space required for an induction section is small versus a total available heating power that can reach more than 4MW.
  • the benefit would be limited because the strip 2 is expected to exit first section 3 at maximum 300°C-350°C, a temperature where the risk of strip oxidation is very high due to O 2 content.
  • the inventors have thus found that the best location for installing the induction heating is between the post-combustion chamber 3 and the direct fired furnace 4.
  • the challenge to meet is that the construction should be designed to resist to a very high gas temperature, more than 1100°C. Therefore, an objective would be to locate the induction heating 11 within the intermediary section 5.
  • the implementation of an induction furnace in the horizontal part between the two deflecting rolls would require an excellent tension control at that location due to the catenary effect of the strip in relation with the small opening of such an induction furnace, typically 80 to 200mm and preferably 100 to 150mm.
  • the present invention solves the above problems by providing a specific intermediary section 5 which receives the two deflecting rolls 7 as well as the electric system 11.
  • fumes 9 from the direct fired furnace 4 can be extracted/deflected toward the post-combustion section 3.
  • a dedicated seal is provided, consisting in a narrow path 12 where some N2 is injected to counter-balance the buoyancy effect. This means that the induction heating 11 can be kept reasonably “cold” because the environment temperature is kept in the range of 300-600°C.
  • the furnace for a hot dip coating line of the present invention is very different of the installation disclosed in US 11,193,182 B2 .
  • the strip is heated in a pre-heating zone by convection and circulation of an inert gas, which is itself heated through a complex heat recovery system fed by the hot fumes produced in the DFF section.
  • This installation thus requires substantial modification of existing lines.
  • the strip temperature at the exit of the induction section is as high as 500°C.
  • the embodiments according to the present invention totally avoid this potential problem as well as an expensive implementation and maintenance of heat exchangers and blowers.
  • the present invention ensures energy savings and further line productivity increase especially for thick strips, combined with the high reactivity of the induction heating system, while keeping the strip in contact with oxidizing fumes below 300°C in the preheating section as it should be the case.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Combustion & Propulsion (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
EP23183522.4A 2023-07-05 2023-07-05 Four de préchauffage pour galvanisation à chaud en continu Withdrawn EP4488608A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP23183522.4A EP4488608A1 (fr) 2023-07-05 2023-07-05 Four de préchauffage pour galvanisation à chaud en continu
PCT/EP2024/063768 WO2025008106A1 (fr) 2023-07-05 2024-05-17 Dispositif pour améliorer la productivité d'une ligne industrielle avec un four

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP23183522.4A EP4488608A1 (fr) 2023-07-05 2023-07-05 Four de préchauffage pour galvanisation à chaud en continu

Publications (1)

Publication Number Publication Date
EP4488608A1 true EP4488608A1 (fr) 2025-01-08

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EP23183522.4A Withdrawn EP4488608A1 (fr) 2023-07-05 2023-07-05 Four de préchauffage pour galvanisation à chaud en continu

Country Status (2)

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EP (1) EP4488608A1 (fr)
WO (1) WO2025008106A1 (fr)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2369349A1 (fr) 1976-10-27 1978-05-26 Nippon Steel Corp Fours verticaux de chauffage a flamme directe pour bandes metalliques
US20190119777A1 (en) * 2016-04-15 2019-04-25 Andritz Technology And Asset Management Gmbh Method and Furnace Installation for Heat Treating Metal Strip

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2369349A1 (fr) 1976-10-27 1978-05-26 Nippon Steel Corp Fours verticaux de chauffage a flamme directe pour bandes metalliques
US4165964A (en) * 1976-10-27 1979-08-28 Nippon Steel Corporation Vertical direct fired strip heating furnaces
US20190119777A1 (en) * 2016-04-15 2019-04-25 Andritz Technology And Asset Management Gmbh Method and Furnace Installation for Heat Treating Metal Strip
US11193182B2 (en) 2016-04-15 2021-12-07 Andritz Technology And Asset Management Gmbh Method and furnace installation for heat treating metal strip

Also Published As

Publication number Publication date
WO2025008106A1 (fr) 2025-01-09

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