EP3959346B1 - Commande en fonction de la vitesse de ligne d'un four pour le traitement thermique d'une feuille d'alliage d'aluminium - Google Patents

Commande en fonction de la vitesse de ligne d'un four pour le traitement thermique d'une feuille d'alliage d'aluminium Download PDF

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EP3959346B1
EP3959346B1 EP20717682.7A EP20717682A EP3959346B1 EP 3959346 B1 EP3959346 B1 EP 3959346B1 EP 20717682 A EP20717682 A EP 20717682A EP 3959346 B1 EP3959346 B1 EP 3959346B1
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Prior art keywords
zone
sheet
temperature
fan
furnace
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EP20717682.7A
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German (de)
English (en)
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EP3959346A1 (fr
Inventor
Johan Petrus Mariette Guido ARRAS
Jason P. LODZIK
Jamaal D. HARRIS
Christopher ELWELL
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Aluminium Duffel BV
Commonwealth Rolled Products Inc
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Alvance Aluminium Duffel BV
Commonwealth Rolled Products Inc
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/002—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working by rapid cooling or quenching; cooling agents used therefor
    • 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
    • C21D11/00—Process control or regulation for heat treatments
    • 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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
    • C22F1/047—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with magnesium as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
    • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
    • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
    • C22F1/053—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with zinc as the next major constituent

Definitions

  • the invention relates to a method for controlling continuous heat- treating and annealing of aluminum alloy sheet at final thickness continuously moving in a floating state substantially horizontally through a continuous convection floating furnace arranged to heat the moving aluminum sheet to a set peak metal temperature (T PMT ).
  • the controlling including controlling fan speeds and furnace air temperature to accommodate variations in line speed of the aluminum alloy sheet continuously moving in the floating state horizontally through the continuous convection floating furnace.
  • aluminum alloy designations and temper designations refer to the Aluminum Association designations in Aluminum Standards and Data and the Teal Sheets Registration Record Series as published by the Aluminum Association in 2018 and frequently updated, and well known to the persons skilled in the art.
  • the industrial scale automotive sheet production of the heat-treatable AlMgSi-alloy series also known as 6000-series aluminum alloys, typical examples include AA6005, AA6014, AA6016 and AA6022, comprises several discrete steps.
  • a rolling slab or ingot is subjected to semi-continuous direct chill (DC)-casting or electromagnetic casting (EMC-casting), also continuous casting like belt or roll casting can be applied.
  • the rolling slab or ingot may be preheated at about 500°C to 580°C for several hours for homogenization of the microstructure.
  • the rolling slab or ingot is hot rolled into hot rolled strip at a gauge of about 3 to 12 mm, the hot rolled strip is typically hot coiled and cooled down to ambient temperature.
  • the hot rolled strip is cold rolled to final gauge in several passes, optionally an intermediate anneal is applied prior to the cold rolling or during the cold rolling process, and at final gauge the strip is annealed to adjust the required material properties.
  • the solution heat treating can be done either in a continuous heat treating furnace or in a batch type furnace.
  • An economical attractive method of producing 6000-series aluminum sheet is by means of continuous solution heat treating at final gauge.
  • the strip material is rapidly cooled or quenched to ambient temperature, for example by means of forced air cooling or spray cooling systems.
  • the main alloying elements Mg and Si are dissolved, leading to a good formability, control of the yield strength and bake hardening behaviour, and brings the sheet material to a T4 temper.
  • 7000-series aluminum alloys are heat treatable aluminum alloys containing zinc as the predominate alloying ingredient other than aluminum.
  • 7000-series aluminum alloys are aluminum alloys having at least 2.0% Zn, and up to 10% Zn, with the zinc being the predominate alloying element other than aluminum.
  • the sheet product has been solution heat treated ("SHT") and cooled, artificially aged, after aging formed in a shaping operation to obtain a structural automotive component of predetermined shape, and subsequently assembled with one or more other metal parts to form an assembly forming a motor vehicle component, and subjected a paint-bake cycle.
  • SHT solution heat treated
  • US 2018/340246 A1 discloses a method for coiling a metal strip that is heat-treated in a furnace immediately before coiling and fed to a coiler at an outlet speed, and then coiled at the coiler at an elevated temperature.
  • the future outlet speed of the metal strip and the heat losses from the metal strip between the furnace and the coiler are calculated via predictive model and the furnace is controlled by the predictive model such that the metal strip is coiled at a pre-defined temperature within a maximum deviation of +/- 5 °C
  • Continuous annealing comprises continuously moving uncoiled non heat-treatable aluminum alloy sheet, for example AA5000 series aluminum sheets, in the direction of its length through a continuous annealing furnace and subsequently quenching the sheets after exiting the furnace.
  • uncoiled non heat-treatable aluminum alloy sheet for example AA5000 series aluminum sheets
  • Continuous solution heat treating also comprises continuously moving uncoiled heat-treatable aluminum alloy sheet, for example AA6000 sheet or AA7000 sheet, through a continuous heat treating furnace and subsequently quenching the sheets after exiting the furnace.
  • the alloy sheet can be hardened at room temperature (e.g., naturally aged) for a duration, hardened for a duration at a slightly elevated temperature (e.g., artificially aged or pre-aged), and/or otherwise further processed (e.g., cleaned, pretreated, coated, or otherwise processed).
  • the aluminum sheets are attached end to end in series and fed to the furnace.
  • a first coil of the aluminum sheet is unrolled to form a sheet and fed to the furnace to be processed and a subsequent coil of the aluminum sheet is unrolled to form the next sheet to be processed.
  • the leading end of this second sheet is attached in series to the trailing end of the previous sheet.
  • a continuous aluminum sheet is fed to the furnace.
  • the trailing edge of the sheet being processed is typically stopped to connect this trailing edge to the leading edge of the new sheet to be processed to form a joint.
  • the continuous heat treatment lines of the invention When used for continuous annealing the continuous heat treatment lines of the invention anneal the aluminum sheet so it is important to control peak metal temperature.
  • Solution heat treatment is similar to annealing, but it involves quenching, which is the rapid cooling of the alloy to preserve the distribution of the elements.
  • quenching is the rapid cooling of the alloy to preserve the distribution of the elements.
  • the continuous heat treatment lines heat the alloy to a temperature at which a particular constituent will enter into solid solution followed by cooling (quenching) at a rate fast enough to prevent the dissolved constituent from precipitating. Maintaining the desired peak metal temperature during heating in both of these processes is important to obtain a product having the desired properties.
  • Annealing and solution heat-treatment involve heating and cooling the sheet to specific temperatures and holding at those temperatures for specific durations of time.
  • the temperature-time profile of sheet can greatly affect the resulting strength and ductility of the final sheet product.
  • a continuous annealing line as well as a continuous solution heat treating line deviation of nominal line speed leads to process conditions in the heat treatment furnace and quench that might lead to non-conforming product characteristics.
  • temperature control of the set (target) peak metal temperature in a furnace for both annealing and solution heat treating is desired to be with a control accuracy of +/-3°C. or better.
  • peak metal temperature is the highest temperature that aluminum alloy achieves in the furnace of a continuous annealing line or a continuous solution heat treating line.
  • the furnace line needs to continue to run sheet through the furnace during deviation of nominal line speed to maintain the sheet being processed at the desired peak metal temperature for the desired time. If the sheet being processed merely stops in the furnace with no changes to heating by the furnace during the attaching then the sheet would overheat.
  • a first accumulator or looper upstream of the furnace provides a first buffer portion of the sheet to feed through the furnace to continue advancing a downstream portion of the aluminum sheet through the furnace while the attaching is being performed.
  • this first buffer resource is finite.
  • the sheet exiting from quenching is cut by shears (for example flying shears) to separate a product sheet from the remainder of the sheet upstream of the cut.
  • the portion of the sheet at the location of the cut is typically stopped during cutting.
  • the furnace line needs to continue to run sheet through the furnace during this attaching to maintain the sheet being processed at the desired peak metal temperature.
  • a second accumulator or looper downstream of the furnace provides sufficient space to accumulate a second buffer portion of the sheet received from quenching to continue advancing an upstream portion of the sheet through the furnace while the cutting is being performed.
  • this second buffer resource is finite.
  • the buffers permit the sheet to continue moving through the furnace at its desired line speed.
  • the target peak metal temperature for the target duration of the target peak metal temperature in the furnace can be maintained during the time permitted by the first and/or second buffer.
  • PMT peak metal temperature
  • PMT peak metal temperature
  • the present invention providing a method for continuously heating aluminum alloy sheet at final thickness in a continuous heat-treating furnace having an entry section and an exit section, wherein the heat treating furnace is a continuous convection floating furnace, comprising:
  • the zone air temperature set point (T zone,Set ) for a respective zone lies within a respective preset temperature range.
  • the line speed set point (v line,Set ) lies within a preset range for the speed of the aluminum alloy sheet.
  • the respective fan speed set points (v fan,Set ) lie within respective preset fan speed ranges.
  • the zone air temperature set point (T zone,Set ) for a respective zone lies within a respective preset temperature range.
  • furnace air temperature at normal undisrupted operation is above peak metal temperature to provide the driving force for heat transfer to heat the moving sheet.
  • the sheet achieves a peak metal temperature initially in a designated zone and maintains temperature in a range from the peak metal temperature to the soaking temperature T Soak which is the predetermined desired minimum temperature selected for annealing or solution heat treating, in subsequent downstream zones until it is cooled after exiting the furnace.
  • T Soak is lower than peak metal temperature (T PMT ).
  • the invention when line speed slows in the zone where peak metal temperature is initially achieved, and likewise the other zones of the furnace, the invention reduces the fan speed and reduces the furnace air temperature. Reducing fan speed while still keeping the moving aluminum sheet floating provide less hot air to the nozzles blowing hot air on the sheet to reduce convection heating of the advancing sheet. Reducing the furnace air temperature to a temperature closer to the peak metal temperature is achieved by admitting outside cooling air and / or reducing heating from the burner. This reducing of furnace air temperature reduces the temperature driving force to heat the advancing sheet. As a result, at the slower line speed the sheet will initially arrive at the desired peak metal temperature in the same zone as it initially did during normal operation or in an earlier upstream zone.
  • the control of the peak metal temperature by fan speed and furnace air temperature compensation maintains temperature typically within +/- 5°C, preferably +/- 2°C of target peak metal temperature for all decelerating, constant, or accelerating speed conditions.
  • the invention may control the sheet temperature by fan speed and furnace air temperature compensation, not only in one or more peak metal temperature zones, but also in additional zones of the furnace.
  • taking measurements in the method of the invention may further comprise:
  • the continuous measuring of the surface temperature of the sheet may be accomplished by an infrared temperature gun or other type of pyrometer, for instance, in the peak metal temperature zone and/or one or more additional zones.
  • the invention may employ a feedback loop with sheet surface temperature measurement(s) instead of, or in addition to, using a model to determine the metal temperature, e.g., peak metal temperature, for example a computer model based on monitoring and measuring fan speed and zone furnace air temperature to determine the heat transfer rate along with line speed measurement to determine the time the metal is exposed to those conditions.
  • FIG. 1 provides a schematic representation of the method in accordance with the invention and the continuous heat-treatment furnace used.
  • the continuous heat-treatment furnace (1) is arranged to transport and to heat-treat uncoiled aluminum sheet (2) moving in the direction of its length along direction of travel "T".
  • the aluminum sheet is uncoiled from coil (8).
  • the aluminum alloy sheet (2) at final gauge has a thickness in the range of 0.3 mm to 4.5 mm, preferably of 0.7 mm to 4.5 mm.
  • the sheet width is typically in the range of about 700 mm to 2700 mm.
  • FIG. 1 shows the aluminum sheet (2) moving through a first looper accumulator (12) upstream of the furnace (3).
  • FIG. 1 also shows a joiner (16) upstream of looper 12 and a shearing station (18) downstream of second looper accumulator (14).
  • the joiner (16) attaches a leading end of the roll (8) to the trailing end of the sheet (2).
  • joining may be by welding, e.g., by means of friction stir welding.
  • the moving aluminum sheet (2) is gradually heated up from room temperature (RT) to the set peak metal temperature (T PMT ) as it moves through the elongated heat treatment chamber (3) of the continuous heat-treatment furnace (1) having an entry portion (4) and an exit portion (5).
  • the moving aluminum sheet (2) is heated in the chamber (3) of the furnace (1) to the set peak metal temperature and soaked for a number of seconds (t SOAK ) in the chamber (3) of the furnace (1) at a temperature in the range from the set peak metal temperature to the soaking temperature T Soak which is the predetermined desired minimum temperature selected for annealing or solution heat treating.
  • T Soak is lower than peak metal temperature (T PMT ).
  • the moving or travelling aluminum sheet moves substantially horizontally in a floating state through the elongated heat treatment chamber (3) over a length of typically at least about 20 meters, preferably over at least 55 meters.
  • the moving aluminum sheet (2) On leaving the exit portion (5) the moving aluminum sheet (2) is rapidly cooled in the cooling section (6) to below about 150°C, e.g. to about room temperature.
  • the aluminum sheet (2) passes through a second looper accumulator (14) downstream of the furnace (3) and then proceeds to a shearing station (18).
  • the shearing station (18) cuts the heat treated aluminum sheet 2 into product sheets 20. For example, flying shears may cut the heat treated aluminum sheet 2 into product sheets 20.
  • FIG. 2 shows a schematic drawing of details of the first looper accumulator (12).
  • the first looper accumulator (12) has a series of rollers defining a path that can be expanded or contracted to accommodate a stoppage of the trailing end of the sheet (2) while the joiner attaches a leading end of the roll (8) to the trailing end of the sheet (2).
  • the second looper accumulator (14) would have the same or similar structure as the first looper accumulator (12) to accommodate the sheet (2) while a portion of sheet (2) downstream of the second looper accumulator (14) is stopped or slowed at the shearing station (18) while the shearing station (18) cuts the heat treated aluminum sheet (2) into the product sheets (20) and being recoiled into individual coils.
  • the continuous heat-treatment furnace (1) is a continuous convection floating furnace arranged to heat the moving aluminum sheet to a set peak metal temperature (T PMT ).
  • the furnace (1) has a series of contiguous zones (10) in its chamber (3) arranged to heat the moving sheet (2) such that during normal operation at least one zone (10) heats the moving sheet (2) to the set peak metal temperature (T PMT ).
  • FIG. 3 shows a schematic drawing of details of a zone (10) of the continuous convection floating furnace (1).
  • Each zone (10) has at least one fan (30) above the aluminum alloy sheet (2) and at least one fan (32) below the aluminum alloy sheet (2).
  • the fans (30), (32) blow recirculated hot furnace air into respective upper and lower nozzle header boxes (34), (36) which include and feed a respective plurality of nozzles which blow the recirculated hot furnace air onto the sheet (2).
  • the upper nozzle header box (34) blows the recirculated furnace air downwardly onto the sheet (2) to heat and stabilize the moving aluminum alloy sheet 2.
  • the lower nozzle header box (36) blows the recirculated furnace air upwardly onto the sheet 2 to heat, float and stabilize the moving aluminum alloy sheet (2) as it travels in direction of travel "T".
  • Each zone (10) typically has at least one convection heater, for example burner (40), above the sheet (2) and at least one burner (42) below the sheet (2).
  • the burners (40), (42) are fed by combustible gas, typically natural gas, lines (44), (46).
  • Each zone (10) also has at least one fresh air feed duct (50) above the sheet (2) and/or below the sheet (2) fed by fresh air intake conduit 51.
  • FIG. 3 illustrates gas firing burners with multiple air circulation fans. These burners are convective heaters. Preferably, gas firing burners with multiple air circulation fans perform the convective heating. However, various other convective heating means can be applied, e.g. resistance heating, in the continuous heat treatment furnace.
  • the moving aluminum sheet moves substantially horizontally through the elongated heat treatment chamber (3) of the continuous furnace over a length of at least about 20 meters, preferably at least 40 meters, and more preferably of at least about 55 meters.
  • a practical maximum length is about 125 meters, but the invention is not limited to this maximum length.
  • FIG. 4 schematically shows a portion of the upper nozzle header box (34) to illustrate nozzles (35) which discharge into the space within the elongated heat treatment chamber (3) of the furnace.
  • FIG. 5 schematically shows a portion of the lower nozzle header box (36) to illustrate nozzles (37) which discharge into the space within the elongated heat treatment chamber (3).
  • the hot-recirculating furnace air nozzles throughout the furnace length heat the strip and keep it afloat on an air cushion.
  • the strip is travelling in a floating state.
  • Such a furnace is also known as convection floating furnace.
  • the elimination of mechanical contact at elevated temperature in the heat-treatment furnace translates into a fault-free strip surface.
  • the continuous heat-treatment furnace can be modular in design; as such the furnace comprises several heating zones that use turbines (not shown) to generate an air channel consisting of top and bottom airflows.
  • the burners that heat the air preferably work with combustion pre-heated air.
  • the moving sheet (2) enters the entry section (4) at V line,Set at ambient temperature and is gradually heated-up while travelling through the continuous heat-treatment furnace to a pre-set heat treatment temperature in the temperature range of 350°C to 590°C, preferably 450°C to 590°C.
  • the average heat-up rate of the aluminum sheet is typically in a range of about 10-15°C/sec for an about 1 mm thick sheet material.
  • the strip temperature may reach the actual pre-set solution heat treatment temperature only far into the second-half of the furnace length or even near the end of the continuous heat-treatment furnace and it is actually soaked at the solution heat treatment temperature for a very short period of time, e.g. a few seconds.
  • the moving sheet leaves the heat-treatment furnace at the exit section (5) and is immediately quenched in the cooling section (6).
  • the soaking temperature T Soak is the predetermined desired minimum temperature selected for annealing or solution heat treating. By definition T Soak is lower than peak metal temperature (T PMT ).
  • the soaking time (t SOAK ) is the time the sheet is held at or above T Soak .
  • the soaking time (t SOAK ) of the moving aluminum sheet is at least one second, typically at least 5 seconds, more typically 5 to 30 seconds, for example 10 seconds.
  • aluminum sheet speed (also known as line speed) through the furnace is at least 3 meters/minute.
  • Typical aluminum sheet speed is about 20 to about 140 m/min.
  • the quenched and moving aluminum sheet is stretched up to about 0.7%, typically in a range of about 0.1% to 0.5%, by means of tension levelling.
  • the stretched and moving aluminum sheet is subsequently cleaned and provided with a coating, e.g., a passivation coating, or otherwise processed.
  • a pre-bake heat treatment heat-treats the stretched aluminum sheet having a passivation coating.
  • the pre-bake treatment increases in particular the paint-bake response of the AA6000-series aluminum sheet material.
  • this balance of properties and process economy has been improved by implementing a control mechanism and apparatus to maintain peak metal temperature in the furnace in the event of a reduction in line speed.
  • the invention controls heat treatment furnace based on the actual line speed.
  • the invention controls the speed of the top and bottom circulation fans and the zone temperature based upon line speed.
  • the top and bottom circulation fans in each zone circulate the air (controlling heat transfer) and floats the sheet through the furnace.
  • the zone temperatures are the furnace air temperatures of the zones of the convection floating furnace.
  • the convection floating furnace typically has more than one zone, for example 4 to 28 zones.
  • the zones are typically heated by burning natural gas or other combustible gas.
  • the fan speed and temperature have direct relation to the heat transfer coefficient (HTC) and line speed has a direct relation to the energy input to the strip over the furnace length.
  • HTC heat transfer coefficient
  • line speed has a direct relation to the energy input to the strip over the furnace length.
  • PMT peak metal temperature
  • time in the furnace will typically change when line speed changes, so maintaining the peak metal temperature and minimizing soak time changes is beneficial.
  • the inventive method for continuously heat-treating aluminum alloy sheet at final thickness in a continuous heat treating furnace having an entry section and an exit section, wherein the heat treating furnace is a continuous convection floating furnace, comprising
  • the measurements are taken for the first zone to achieve peak metal temperature and all the contiguous heat treatment zones in the furnace downstream of this peak metal temperature zone, more preferably all the contiguous heat treatment zones in the furnace, and the fan speeds and furnace air temperatures adjusted for the first zone to achieve peak metal temperature and all contiguous heat treatment zones in the furnace downstream of this peak metal temperature zone, more preferably all the contiguous heat treatment zones in the furnace.
  • the invention may control the sheet temperature by fan speed and furnace air temperature compensation, not only in one or more peak metal temperature zones, but also in additional zones of the furnace.
  • taking measurements in the method of the invention may further comprise:
  • Taking the measurements and adjusting fan speeds and furnace air temperature in all the contiguous heat treatment zones involves a method for continuously heat treating aluminum alloy sheet at final thickness in a continuous heat treating furnace having an entry section and an exit section, wherein the heat treating furnace is a continuous convection floating furnace, comprising:
  • the zone air temperature set point (T zone,Set ) for a respective zone lies within a respective preset temperature range.
  • the line speed set point (v line,Set ) lies within a preset range for the speed of the aluminum alloy sheet.
  • the respective fan speed set points (v fan,Set ) lie within respective preset fan speed ranges.
  • the zone air temperature set point (T zone,Set ) for a respective zone lies within a respective preset temperature range.
  • the values for "x" and "y” can be empirically determined by a user by running computer simulation furnace models that calculate the effect of varying the line speed on peak metal temperature. Then to validate these findings actual furnace trials can be conducted varying the line speed and sampling the products from these trials. Changes in product properties indicate the changes in PMT resulting from these line speed changes.
  • Parameters x, y for an actual furnace are measured empirically by measuring actual aluminum sheet temperatures with sensors over multiple furnace test runs at varying conditions of fan speed and zone temperature and time. To estimate temperature during normal operation the invention monitors and measures fan speed and zone furnace air temperature to determine the heat transfer rate. In addition, the invention monitors and measures line speed to determine the time the metal sheet is exposed to those conditions. Then an online computer model based upon these measurements uses this information in heat transfer equations to calculate a peak metal temperature. Heat transfer equations for convective heat transfer are known to those skilled in the art. See for example, Engineering Heat Transfer, M.M. Rathore, Jones & Bartlett Learning, 2d Ed. (2011 ); or Heat Transfer, J.P. Holman, McGraw-Hill, 10th ed. (2010 ).
  • PMT peak metal temperature
  • the model may be based on monitoring and measuring fan speed (rpm) and zone furnace air temperature to determine the heat transfer rate along with line speed measurement to determine the time the metal is exposed to those conditions
  • the continuous measuring of the surface temperature of the sheet may also be accomplished by an infrared temperature gun or other type of pyrometer, for instance, in the peak metal temperature zone and/or one or more additional zones.
  • the invention may employ a feedback loop with sheet surface temperature measurement(s) instead of, or in addition to, using a model to determine the metal temperature, e.g., peak metal temperature.
  • This control of fan speed and furnace air temperature according to equations (I) and (II) should be activated once the actual line speed differs from the line speed set point v line,Set by more than a settable tolerance, e.g., 0 to 10% deviation from line speed set point, typically 1% to 5% deviation from line speed set point.
  • Fan speed parameter x is user selectable per furnace zone (in machine parameters) based on empirical data as explained above. However, in general x is between 0.6 and 0.95, preferably 0.65 to 0.95, more preferably 0.75 to 0.95, and may be the same or different for each zone.
  • fans above and below the sheet There are fans above and below the sheet.
  • the fans above may be at a different rpm than the fans below.
  • the invention typically controls/adjusts the actual fan speed v fan,act rpm of both sets of fans by the same ratio relative to their respective fan speed set point v fan,Set .
  • the reduction of fan speed is limited by: Minimum fan speeds to maintain flotation of the sheet above furnace components to avoid damage, such as scratching, to the sheet, Maximum soaking time; and Minimum heating rates. This is generally no more than a 35% reduction in rpm, preferably no more than a 30 % reduction in rpm.
  • Furnace air temperature parameter y is user selectable per furnace zone (in machine parameters) based on empirical data as explained above. However, in general y is between 0 and 0.2, preferably 0 and 0.1, more preferably between 0.02 and 0.1, and may be the same or different for each zone.
  • furnace air temperature should be reduced no more than 10 °C, preferably no more than 5 °C, such that the inventive method can cool and heat up the furnace air in the same time period as the duration of the speed change.
  • Every zone (10) typically has at least one burner (two shown in FIG. 3 ) and at least one fresh air cooling intake (two shown in FIG. 3 ).
  • Every zone (10) typically has at least one burner (two shown in FIG. 3 ) and at least one fresh air cooling intake (two shown in FIG. 3 ).
  • the feed of combustible gas to the burner (40), (42) can be increased and / or the influx of air from the fresh air cooling intake (51) to the fresh air feed duct (50) can be adjusted.
  • the feed of combustible gas to the burner (40), (42) can be increased and / or the influx of air from the fresh air cooling intake can be decreased.
  • the feed of combustible gas to the burner (40), (42) can be decreased and / or the influx of air from the fresh air cooling intake can be increased.
  • the control of the peak metal temperature by means of fan speed and temperature compensation maintains temperature typically within +/- 5°C, preferably +/-3°C, more preferably +/- 2°C of target peak metal temperature for all decelerating, constant, or accelerating speed conditions.
  • FIG. 3 also schematically shows control scheme details of the zone (10) of the continuous convection floating furnace (1) that may be employed to implement this inventive method.
  • Each zone (10) also has at least one furnace air temperature sensor (52) in communication with a temperature controller (54).
  • the furnace air temperature sensors in the invention may be, for example, thermocouples.
  • the temperature controller (54) controlling the combustion gas feed valves (56) and the fresh air intake valves (58).
  • the line speed sensor (13) is also in communication with the temperature controller (54) and fan speed controllers (60), (62).
  • the line speed sensor (13) senses a change in the line speed of the sheet (2) it sends signals to the fan speed controller (60) and to the temperature controller (54) to control the respective speed of the fans (30), (32) and the furnace air temperature according to according to the above listed equation (I) and equation (II).
  • line speed sensor (13) senses a change in the line speed of the sheet (2) it sends at least one signal to the fan speed controller (60) to adjust the speeds of the respective fans (30), (32) according to equation (I). Also, when the line speed sensor (13) senses a change in the line speed of the sheet (2) it sends signals to the furnace air temperature controller (54) to control furnace air temperature according to equation (II).
  • the furnace air temperature is controlled by controlling the air intake valves (58) which admit cooling air and the combustion gas valves 56 which control feed of combustion gas to the burners (40), (42).
  • the method may further include taking measurements representative of heat transfer to the sheet as the sheet advances through the elongated heat treatment chamber of the furnace which comprises measuring line speed of the sheet through the elongated heat treatment chamber, measuring the fan speeds of fans above and below the moving sheet in each contiguous heat treatment zone and measuring the furnace air temperature in each contiguous heat treatment zone;
  • the sheet temperature estimates are sheet surface temperature estimates.
  • the method may further include taking measurements representative of heat transfer to the aluminum alloy sheet as the aluminum alloy sheet moves through the elongated heat treatment chamber of the furnace, which comprises from time to time taking measurements including speed of the aluminum alloy sheet through the elongated heat treatment chamber, speed of the fans above and below, and air temperature in each of the contiguous heat treatment zones,
  • a conventional process for producing aluminum alloy products in rolled form with solution heat treating includes the processing steps wherein an aluminum alloy body is cast, after which it is homogenized and then hot rolled to an intermediate gauge. Next, the aluminum alloy body may be cold rolled. Next it is solution heat treated and quenched, for example by means of water such as water quenching or water spray quenching.
  • Solution heat treating and quenching and the like, generally referred to herein as “solutionizing”, means heating an aluminum alloy body to a suitable temperature, generally above the solvus temperature, holding at that temperature long enough to allow soluble elements to enter into solid solution, and cooling rapidly enough to hold the elements in solid solution.
  • the process includes continuously moving uncoiled heat treatable aluminum alloy sheet in the direction of its length horizontally through the continuous heat treatment furnace arranged to heat the moving aluminum sheet to heat the product at a heating rate in the range of 2 to 200 °C./sec to a solution heat treating temperature of typically 350°C to 590°C, preferably 370°C to 590°C, more preferably 460°C to 580°C, or more preferably 500°C to 590°C, furthermore preferably 480°C to 580°C and soak the sheet at this temperature for a soaking time (t SOAK ).
  • t SOAK soaking time
  • T Soak is the predetermined desired minimum temperature selected for the solution heat treating.
  • T Soak is lower than peak metal temperature (T PMT ).
  • the soaking time (t SOAK ) is the time the sheet is held at or above T Soak .
  • the soaking time (t SOAK ) of the moving aluminum sheet is at least one second, for example at least 1 to at most 100 sec, typically at least 5 seconds, more typically 5 to 30 seconds, e.g., 10 seconds.
  • solution heat treating continuously moving uncoiled heat treatable AlMgSi aluminum alloy sheet also known as AA6000-series alloy sheet
  • the sheet is heated to and held (soaked) at solution heat treating temperature in a range of 500°C to 590°C, preferably 520°C to 580°C, to dissolve in particular Mg and Si.
  • the furnace being controlled according to the method of the invention.
  • the sheet exiting the furnace is quenched typically by quench water at a cooling rate in the range of 10 to 500 °C./sec to below a temperature of 150°C.
  • Typical AA6000 alloys treatable according to the invention include 6005, 6009, 6010, 6111, 6014, 6016, 6022, 6061, 6181, 6082, 6182, and various others.
  • Solution heat treating of AA6000 series alloy involves recovery in the upstream zone or zones in which the metal softens by rearranging the cold worked structure, recrystallization of the metal in the middle zone or zones, and grain growth in the metal in the downstream zone or zones of the furnace where the metal achieves and soaks at soaking temperature during which the small recrystallized grains will grow to the desired size.
  • solution heat treating continuously moving uncoiled heat treatable aluminum alloy sheet of AA7000-series alloy at final gauge the sheet is heated to and held at solution heat treating temperature commonly in a range of about 430°C to 560°C, preferably 450°C to 560°C.
  • solution heat treating temperature commonly in a range of about 430°C to 560°C, preferably 450°C to 560°C.
  • the solid solution formed at high temperature may be retained in a supersaturated state by cooling with sufficient rapidity to restrict the precipitation of the solute atoms as coarse, incoherent particles, typically by quench water at a cooling rate in the range of 10 to 500 °C./sec to below a temperature of 150°C.
  • the AA7000-series aluminum alloy has a Cu-content of less than 0.25% and is one of the following AA7000-series aluminum alloys, as defined by the Aluminum Association: 7003, 7004, 7204, 7005, 7108, 7108A, 7015, 7017, 7018, 7019, 7019A, 7020, 7021, 7024, 7025, 7028, 7030, 7031, 7033, 7035, 7035A, 7039, 7046, and 7046A.
  • the solution heat treatment temperature should be at least 370°C.
  • a preferred minimum temperature is 400°C, more preferably 430°C, furthermore preferably 450°C, and most preferably 470°C.
  • the solution heat-treatment temperature should not exceed 560°C.
  • a preferred maximum temperature is 545°C, and preferably not more than 530°C.
  • the AA7000-series aluminum alloy has a Cu-content of 0.25% or more and is one of the following AA7000-series aluminum alloys, as defined by the Aluminum Association: 7009, 7010, 7012, 7014, 7016, 7116, 7022, 7122, 7023, 7026, 7029, 7129, 7229, 7032, 7033, 7034, 7036, 7136, 7037, 7040, 7140, 7041, 7049, 7049A, 7149, 7249, 7349, 7449, 7050, 7050A, 7150, 7250, 7055, 7155, 7255, 7056, 7060, 7064, 7065, 7068, 7168, 7075, 7175, 7475, 7076, 7178, 7278, 7278A, 7081, 7181, 7085, 7185, 7090, 7093, 7095 and 7099.
  • the solution heat treatment temperature should be at least 400°C.
  • a preferred minimum temperature is 450°C, furthermore preferably 460°C, and most preferably 470°C.
  • the solution heat-treatment temperature should not exceed 560°C.
  • a preferred maximum temperature is 530°C, and preferably not more than 520°C.
  • the AA7000-series aluminum sheet may have Zn in the range of 2.0% to 10.0%, and preferably in the range of 3.0% to 9.0%.
  • the AA7000-series aluminum sheet may have Mg in the range of 1.0% to 3.0%.
  • the AA7000-series aluminum sheet may have Cu is the range of ⁇ 0.25%, preferably Cu in the range of 0.25% to 3.5%.
  • the AA7000-series aluminum sheet may further comprise
  • the AA7000-series aluminum sheet may have a recrystallized microstructure.
  • the AA7000-series aluminum alloy body may be optionally stretched a small amount (e.g., about 1-5%) for flatness, thermally treated (e.g. by natural ageing or artificial ageing) and optionally subjected to final treatment practices (e.g. a forming operation, paint-bake cycle in case of an automotive application).
  • thermally treated e.g. by natural ageing or artificial ageing
  • final treatment practices e.g. a forming operation, paint-bake cycle in case of an automotive application.
  • the method and apparatus of the invention can be applied to a broad range of heat-treatable aluminum alloys to be annealed or solution heat treated.
  • the invention may be employed with lower solution heat treatment temperatures, e.g., in the range of 460°C to 480°C.
  • the heat treatment process includes continuously moving uncoiled heat treatable aluminum alloy sheet in the direction of its length horizontally through a continuous annealing furnace arranged to heat the moving aluminum sheet to heat the product to a temperature in the range of 370°C to 560°C, more typically 480°C to 560°C, for a duration of 1 to at most 100 sec.
  • the moving aluminum sheet is rapidly cooled on leaving the furnace.
  • the cooling is typically by quench water at a cooling rate in the range of 10 to 500 °C./sec to below a temperature below 150°C.
  • Typical AA5000 alloys treatable according to the present invention include 5030, 5051, 5182, 5454, 5754, and various others.
  • FIG. 6 shows a chart illustrating the control of peak metal temperature (PMT) and line speed according to the present invention. This shows as aluminum alloy sheet material went through a speed reduction from 50 to 35 m/min PMT (°C) in a furnace the peak metal temperature varied an average +/- 1° C. The fan speed and air temperature were adjusted according to the invention.
  • PMT peak metal temperature

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Claims (17)

  1. Procédé pour chauffer en continu une tôle (2) en alliage d'aluminium à une épaisseur finale dans un four de traitement thermique en continu (1) ayant une section d'entrée (4) et une section de sortie (5), dans lequel le four de traitement thermique (1) est un four à zone flottante à convection continue (1), comprenant les étapes consistant à
    déplacer horizontalement en continu une tôle (2) en alliage d'aluminium non enroulée dans un état flottant dans un trajet le long d'une direction de sa longueur à travers une pluralité de zones de traitement thermique contiguës (10) d'une chambre de traitement thermique allongée (3) du four de traitement thermique en continu (1) agencée pour chauffer la tôle (2) d'aluminium en déplacement jusqu'à une température de métal de pointe de consigne (TPMT) dans la plage de températures de 350 °C à 590 °C ;
    dans lequel les zones de traitement thermique contiguës (10) ont des chauffages à convection à commande indépendante le long du trajet destinés à chauffer la tôle (2) en alliage d'aluminium et des ventilateurs à commande indépendante (30, 32) qui soufflent au-dessus et au-dessous de la tôle (2) en alliage d'aluminium le long du trajet pour guider la tôle (2) en alliage d'aluminium le long du trajet lorsque la tôle (2) en alliage d'aluminium se déplace horizontalement à travers la chambre de traitement thermique allongée,
    dans lequel l'une au moins desdites zones de traitement thermique contiguës (10) est une zone de température de métal de pointe (10) qui a une température de tôle en alliage d'aluminium cible qui est la température de métal de pointe de la tôle (2) en alliage d'aluminium dans la chambre de traitement thermique allongée ;
    prendre des mesures représentatives d'un transfert thermique à la tôle (2) en alliage d'aluminium lorsque la tôle (2) en alliage d'aluminium se déplace à travers la chambre de traitement thermique allongée, les mesures incluant une vitesse de la tôle (2) en alliage d'aluminium à travers la chambre de traitement thermique allongée, une vitesse des ventilateurs (30, 32) soufflant au-dessus et au-dessous de la tôle (2) en alliage d'aluminium, et une température d'air de four, et en option une température de surface de la tôle (2),
    dans lequel ladite étape consistant à prendre des mesures comprend :
    de mesurer en continu la vitesse linéaire de déplacement horizontal de la tôle (2) en alliage d'aluminium à travers le four (1) et de générer un signal de vitesse proportionnel à la vitesse linéaire mesurée réelle vline,act de la tôle (2) en alliage d'aluminium à travers le four (1), la vitesse linéaire de la tôle (2) en alliage d'aluminium à travers le four (1) ayant un point de consigne de vitesse linéaire (vline,Set),
    mesurer en continu les vitesses des ventilateurs de four (30, 32) au-dessus et au-dessous de la tôle (2) en alliage d'aluminium dans ladite zone de température de métal de pointe (10), les vitesses de ventilateurs des ventilateurs (30, 32) au-dessus et au-dessous de la tôle (2) en alliage d'aluminium ayant des point de consigne de vitesse de ventilateurs (vfan,Set) respectifs, le point de consigne de vitesse de ventilateurs des ventilateurs (30, 32) au-dessus de la tôle (2) en alliage d'aluminium pouvant être identique ou différent du point de consigne de vitesse de ventilateurs des ventilateurs (30, 32) au-dessous de la tôle (2) en alliage d'aluminium ;
    mesurer en continu la température d'air de four dans ladite zone de température de métal de pointe (10), la température d'air de four dans ladite zone de température de métal de pointe (10) ayant un point de consigne de température d'air de zone (Tzone,Set) ; et
    en option, mesurer en continu la température de surface de la tôle (2),
    dans lequel, pendant un fonctionnement normal, la vitesse linéaire réelle mesurée, les vitesses de ventilateur réelles mesurées dans ladite zone de température de métal de pointe (10), et la température d'air de four réelle mesurée dans ladite zone de température de métal de pointe (10), simultanément, sont respectivement dans les plages fixées au préalable pour le point de consigne de vitesse linéaire (vline,Set), les points de consigne de vitesse de ventilateurs (vfan,Set), et le point de consigne de température d'air de zone (Tzone,Set) dans ladite zone de température de métal de pointe (10) ;
    changer les vitesses de ventilateur et la température d'air de four dans ladite zone de température de métal de pointe (10), en réponse à la vitesse linéaire réelle mesurée vline,act et au point de consigne de vitesse linéaire vline,Set selon l'équation (I) et l'équation (II) : v fan , act = v line , act v line , Set x × v fan , Set
    Figure imgb0019
     T zone , act = v line , act v line , Set y × T zone , Set
    Figure imgb0020
    dans lequel :
    vline,act est la vitesse linéaire réelle mesurée, par exemple en m/min,
    vline,Set est le point de consigne de vitesse linéaire, par exemple en m/min,
    vfan,act et la vitesse de ventilateurs réelle en tpm dans la zone de température de métal de pointe (10),
    x est entre 0,6 et 0,95, de préférence de 0,65 à 0,95, de toute préférence de 0,75 à 0,95,
    vfan,Set est le point de consigne de vitesse de ventilateurs en tpm dans la zone de température de métal de pointe (10), le point de consigne de chaque ventilateur (30, 32) au-dessus de la tôle (2) en déplacement pouvant être identique ou différent du point de consigne de chaque ventilateur (30, 32) au-dessous de la tôle (2) en déplacement,
    Tzone,act est la température d'air de zone réelle dans la zone de température de métal de pointe (10),
    Tzone,Set est le point de consigne de température d'air de zone dans la zone de température de métal de pointe (10),
    y est entre 0 et 0,2, de préférence 0 et 0,1.
  2. Procédé selon la revendication 1, dans lequel une étape consistant à ajuster une vitesse de ventilateurs et une température d'air de four quand la vitesse linéaire est ajustée commande une température de métal de pointe dans la zone de température de métal de pointe de four (10) dans la plage de +/- 5 °C, de préférence de +/- 3 °C, de toute préférence de +/- 2 °C d'une température de métal de pointe cible de consigne (TPMT).
  3. Procédé selon la revendication 1 ou 2, dans lequel une température d'air de four réelle est réduite relativement à un point de consigne de température d'air de four à raison de pas plus de 10 °C, de préférence pas plus de 5 °C.
  4. Procédé selon l'une quelconque des revendications 1 à 3, qui inclut l'étape consistant à obtenir ladite au moins une mesure de température d'air de four avec au moins un capteur de température à l'intérieur du four (1).
  5. Procédé selon l'une quelconque des revendications 1 à 4, dans lequel la tôle (2) se déplace le long de la trajectoire à raison d'au moins trois mètres par minute.
  6. Procédé selon l'une quelconque des revendications 1 à 5, dans lequel la tôle (2) est à une température de métal de pointe pendant une durée de 1 seconde à 100 secondes.
  7. Procédé selon l'une quelconque des revendications 1 à 6, comprenant :
    au moins un contrôleur de vitesse de ventilateurs connecté à un capteur mesurant la vitesse linéaire et aux ventilateurs (30, 32) dans la zone de température de métal de pointe (10), ledit contrôleur de vitesse de ventilateurs commandant les ventilateurs pour changer une vitesse de ventilateurs respective de vfan,Set à vfan,act dans l'éventualité d'un changement de vline,act à une valeur différente de vline,Set ;
    au moins un contrôleur de brûleurs connecté au capteur mesurant la vitesse linéaire de la tôle (2) d'aluminium ; et
    au moins un contrôleur de température d'air de four connecté à un capteur de température mesurant la température de l'atmosphère de four, ledit contrôleur de température d'air de four commandant les brûleurs pour changer une température d'air de four de Tzone,Set à Tzone,act dans l'éventualité d'un changement de vline,act changeant à une valeur différente de vline,Set.
  8. Procédé selon l'une quelconque des revendications 1 à 7, dans lequel le four en continu (1) est chauffé à l'aide de moyens de chauffage par convection, de préférence de moyens d'allumage au gaz.
  9. Procédé selon l'une quelconque des revendications 1 à 8, dans lequel la température de métal de pointe est de 370 °C à 590 °C, de préférence de 460 °C à 580 °C, de toute préférence de 480 °C à 580 °C.
  10. Procédé selon l'une quelconque des revendications 1 à 9, dans lequel la tôle (2) en alliage d'aluminium est une tôle (2) en alliage d'aluminium AA6000 susceptible de traitement thermique et la température de métal de pointe de consigne (TPMT) est dans une plage de 480 °C à 590 °C, de préférence de 500 °C à 580 °C, pour dissoudre le Mg et le Si.
  11. Procédé selon l'une quelconque des revendications 1 à 10, dans lequel la tôle (2) en alliage d'aluminium est une tôle (2) en alliage d'aluminium AA7000 de susceptible de traitement thermique et la température de métal de pointe de consigne (TPMT) est dans une plage de 430 °C à 560 °C.
  12. Procédé selon l'une quelconque des revendications 1 à 11, dans lequel la tôle (2) en alliage d'aluminium est une tôle (2) en alliage d'aluminium AA7000 susceptible de traitement thermique et la température de métal de pointe de consigne (TPMT) est dans la plage de 460 °C à 480 °C.
  13. Procédé selon l'une quelconque des revendications 1 à 12, dans lequel le procédé recuit une tôle (2) en alliage d'aluminium série AA5000 non susceptible de traitement thermique,
    dans lequel une tôle (2) en alliage d'aluminium série AA5000 non susceptible de traitement thermique non enroulée en déplacement se déplace dans la direction de sa longueur à travers le four de traitement thermique en continu (1) agencé pour chauffer la tôle (2) d'aluminium en déplacement à une température de métal de pointe de consigne (TPMT) dans la plage de 350 °C à 560 °C, et
    dans lequel la tôle (2) d'aluminium en déplacement est rapidement refroidie depuis TPMT jusqu'à moins de 150°C environ en quittant le four (1).
  14. Procédé selon l'une quelconque des revendications 1 à 13, comprenant les étapes consistant à
    prendre des mesures représentatives d'un transfert thermique à la tôle (2) lorsque la tôle (2) avance à travers la chambre de traitement thermique allongée (3), l'étape comprenant de mesurer la vitesse linéaire de la tôle (2) à travers la chambre de traitement thermique allongée, de mesurer les vitesses de ventilateurs de ventilateurs (30, 32) au-dessus et au-dessous de la tôle (2) en déplacement dans chaque zone de traitement thermique contiguë (10), et de mesurer la température d'air de four dans chaque zone de traitement thermique contiguë (10) ;
    comparer les vitesses de ventilateurs mesurées à une plage de vitesses de ventilateurs fixée au préalable sous la forme de valeurs spécifiées ;
    comparer la température d'air de four mesurée à une plage de températures d'air de four fixée au préalable sous la forme de valeurs spécifiées ;
    fournir une pluralité de différents brûleurs à commande indépendante à différentes positions le long de la trajectoire, fournir une pluralité de différents ventilateurs à commande indépendante (30, 32) au-dessus et au-dessous de la tôle (2) d'aluminium en déplacement à différentes positions le long de la trajectoire ;
    générer une estimation de température de tôle en temps réel le long de la trajectoire, l'estimation de température de tôle étant établie sous la forme d'une fonction de la vitesse linéaire de tôle dans la chambre de traitement thermique allongée, de la température d'air de four dans chaque zone de traitement thermique contiguë (10), et de la vitesse de ventilateurs dans chaque zone de traitement thermique contiguë (10) ;
    ajuster l'estimation de température de tôle en réponse à un changement dans au moins un élément parmi la vitesse linéaire de tôle, la température d'air de four dans l'une au moins desdites zones de traitement thermique contiguës (10), et les vitesses de ventilateurs dans l'une au moins desdites zones de traitement thermique contiguës (10).
  15. Procédé selon la revendication 14, dans lequel les estimations de températures de tôle sont des estimations de températures de surface de tôle.
  16. Procédé selon l'une quelconque des revendications 1 à 15, dans lequel ladite étape consistant à prendre des mesures représentatives d'un transfert de chaleur à la tôle (2) en alliage d'aluminium lorsque la tôle (2) en alliage d'aluminium se déplace à travers la chambre de traitement thermique allongée, comprend de prendre de temps en temps des mesures incluant une vitesse de la tôle (2) en alliage d'aluminium à travers la chambre de traitement thermique allongée, une vitesse des ventilateurs (30, 32) au-dessus et au-dessous, et une température d'air dans chaque zone (10),
    générer une estimation de température de tôle en temps réel le long du trajet, l'estimation de température de tôle étant établie sous la forme d'une fonction d'une vitesse de la tôle (2) en alliage d'aluminium à travers la chambre de traitement thermique allongée, d'une vitesse des ventilateurs (30, 32) au-dessus et au-dessous, et d'une température d'air dans chaque zone (10) ; dans lequel ladite étape consistant à générer une estimation de température de tôle en temps réel le long du trajet comprend d'estimer la température de tôle en alliage d'aluminium dans la zone de température de métal de pointe (10) au point de consigne de vitesse linéaire vline,Set, et au point de consigne de vitesse de ventilateurs vfan,Set,
    ajuster l'estimation de température de tôle en réponse à un changement dans au moins un élément parmi la vitesse de tôle, la vitesse des ventilateurs (30, 32) au-dessus et au-dessous, et la température d'air dans chaque zone (10) ;
    comparer l'estimation de température de tôle à une distribution de température désirée pour déterminer des différences quelconques entre l'estimation de température de tôle et la distribution de température désirée, la distribution de température désirée incluant une pluralité de points de consigne de température pour la tôle (2) le long de la trajectoire, chaque point de consigne représentant une valeur cible ;
    pour chacun des brûleurs et des ventilateurs (30, 32), réguler un fonctionnement sous la forme d'une fonction des différences avec contrôleur de rétroaction à boucle fermée ; estimer, en temps réel, un profil de température de tôle le long de la trajectoire pour la tôle (2) sur la base de l'estimation de température de tôle et de la longueur de la tôle (2), et afficher visuellement une représentation en temps réel de l'estimation de la température de tôle et un temps de trempage.
  17. Procédé selon l'une quelconque des revendications 1 à 16, dans lequel ladite étape consistant à prendre des mesures comprend en outre :
    de mesurer en continu les vitesses des ventilateurs de four (30, 32) au-dessus et au-dessous de la tôle (2) en alliage d'aluminium dans une ou plusieurs zones additionnelles (10) desdites zones contiguës (10), lesdites zones additionnelles (10) étant en addition à ladite zone de température de métal de pointe (10), dans lequel, pour chaque zone additionnelle (10), les vitesses de ventilateurs des ventilateurs (30, 32) au-dessus et au-dessous de la tôle (2) en alliage d'aluminium ont des points de consigne de vitesses de ventilateurs (30, 32) respectifs, le point de consigne de vitesse de ventilateurs de chaque ventilateur (30,32) au-dessus de la tôle (2) en alliage d'aluminium pouvant être identique ou différent du point de consigne de vitesse de ventilateur de chaque ventilateur (30, 32) au-dessous de la tôle (2) en alliage d'aluminium ;
    mesurer en continu la température d'air de four dans chaque zone additionnelle (10), la température d'air de four dans chaque zone additionnelle (10) ayant un point de consigne de température d'air de zone (Tzone,Set) respectif ; et
    en option, mesurer en continu la température de surface de la tôle (2),
    dans lequel, pendant un fonctionnement normal, la vitesse linéaire réelle mesurée, les vitesses de ventilateurs réelles mesurées dans chaque zone additionnelle (10), et la température d'air de four réelle mesurée dans chaque zone additionnelle (10), simultanément, sont respectivement dans les plages fixées au préalable pour le point de consigne de vitesse linéaire (vline,Set), les point de consigne de vitesses de ventilateurs (vfan,Set), et le point de consigne de température d'air de zone (Tzone,Set) dans la zone additionnelle (10) ;
    changer respectivement les vitesses de ventilateurs et la température d'air de four dans chaque zone additionnelle (10), en réponse à la vitesse linéaire réelle mesurée vline,act et au point de consigne de vitesse linéaire vline,Set selon l'équation (I) et l'équation (II) : v fan , act = v line , act v line , Set x × v fan , Set
    Figure imgb0021
     T zone , act = v line , act v line , Set y × T zone , Set
    Figure imgb0022
    dans lequel :
    vline,act est la vitesse linéaire réelle mesurée, par exemple en m/min,
    vline,Set est le point de consigne de vitesse linéaire, par exemple en m/min,
    vfan,act est la vitesse de ventilateurs réelle en tpm dans la zone additionnelle (10),
    x est entre 0,6 et 0,95, de préférence de 0,65 à 0,95, de toute préférence de 0,75 à 0,95,
    vfan,Set est le point de consigne de vitesse de ventilateurs en tpm dans la zone additionnelle (10), le point de consigne des ventilateurs (30, 32) au-dessus de la tôle (2) en déplacement pouvant être identique ou différent du point de consigne des ventilateurs (30, 32) au-dessous de la tôle (2) en déplacement,
    Tzone,act est la température d'air de zone réelle dans la zone additionnelle (10) respective,
    Tzone,Set est le point de consigne de température d'air de zone dans la zone additionnelle (10) respective,
    y est entre 0 et 0,2, de préférence 0 et 0,1.
EP20717682.7A 2019-04-23 2020-04-15 Commande en fonction de la vitesse de ligne d'un four pour le traitement thermique d'une feuille d'alliage d'aluminium Active EP3959346B1 (fr)

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US5639418A (en) * 1996-03-25 1997-06-17 Surface Combustion, Inc. Strip floater furnace with closed loop recirculation
US6129258A (en) * 1999-02-16 2000-10-10 Seco/Warwick Corporation Muffle convection brazing and annealing system and method
WO2010049445A1 (fr) 2008-10-30 2010-05-06 Aleris Aluminum Duffel Bvba Composant structurel d'automobile de tôle d'alliage d'aluminium
CA2960321C (fr) 2014-09-12 2022-08-16 Aleris Aluminum Duffel Bvba Procede de recuit de materiau de feuille d'alliage d'aluminium
EP3006579B2 (fr) 2014-12-11 2022-06-01 Aleris Aluminum Duffel BVBA Procédé de traitement thermique en continu de matériau de feuille d'alliage d'aluminium de la série 7000
DE102017110273B4 (de) * 2017-05-11 2019-05-09 Ebner Industrieofenbau Gmbh Ofensystem mit Heißluftbeheizung
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