(19)
(11)EP 3 225 705 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
04.11.2020 Bulletin 2020/45

(21)Application number: 15862866.9

(22)Date of filing:  01.09.2015
(51)International Patent Classification (IPC): 
C21D 9/573(2006.01)
C21D 1/63(2006.01)
C21D 1/18(2006.01)
(86)International application number:
PCT/JP2015/004432
(87)International publication number:
WO 2016/084283 (02.06.2016 Gazette  2016/22)

(54)

METHOD FOR MANUFACTURING METAL PLATES AND QUENCHING DEVICE

VERFAHREN ZUR HERSTELLUNG VON METALLPLATTEN UND ABSCHRECKVORRICHTUNG

PROCÉDÉ DE FABRICATION DE TÔLES MÉTALLIQUES ET DISPOSITIF DE TREMPE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 28.11.2014 JP 2014240836

(43)Date of publication of application:
04.10.2017 Bulletin 2017/40

(73)Proprietor: JFE Steel Corporation
Tokyo 100-0011 (JP)

(72)Inventors:
  • YOSHIMOTO, Soshi
    Tokyo 100-0011 (JP)
  • MIYAKE, Masaru
    Tokyo 100-0011 (JP)
  • TAKEDA, Gentaro
    Tokyo 100-0011 (JP)

(74)Representative: Haseltine Lake Kempner LLP 
Bürkleinstrasse 10
80538 München
80538 München (DE)


(56)References cited: : 
GB-A- 1 148 912
JP-A- S59 153 843
JP-B1- S5 218 124
JP-A- H04 289 130
JP-B1- S 462 733
JP-B1- S5 218 124
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Technical Field



    [0001] The present invention relates to a method for manufacturing a metal sheet in such a manner that shape defects caused in the metal sheet during rapid quenching are suppressed using a continuous annealing line for performing heating, soaking, cooling, and reheating while the metal sheet is being continuously fed and also relates to a rapid quenching unit.

    Background Art



    [0002] In the manufacture of metal sheets including steel sheets, properties are adjusted in such a manner that phase transformation is induced by cooling the metal sheets in a continuous annealing line after heating. In recent years, high-tensile strength steel sheets have been increasingly used in the automotive industry for the purpose of achieving the weight reduction and crash safety of automobiles. In order to respond to such a demand trend, the importance of rapid cooling techniques advantageous in manufacturing high-tensile strength steel sheets is growing. A water quenching method having the highest cooling rate is generally a way to rapidly cool a steel sheet in such a manner that cooling water is applied to the steel sheet from quenching nozzles placed in water at the same time that the heated steel sheet is immersed in water. In this method, there is a problem in that shape defects are caused in a metal sheet by out-of-plane deformation including camber and wavy deformation.

    [0003] Patent Literature 1 proposes a technique in which bridle rolls are provided upstream and downstream of a rapid quenching section as tension-changing means capable of changing the tension of a steel sheet subjected to a rapid quenching step for the purpose of reducing the wavy deformation of a metal sheet that occurs during rapid quenching in a continuous annealing furnace.

    [0004] Patent Literature 2 proposes a technique in which, in consideration of the fact that shape defects are caused because compressive thermal stress is generated in lateral directions of a metal sheet at a quenching start temperature (cooling start temperature) and therefore the metal sheet buckles, out-of-plane deformation is reduced in such a manner that both sides of the metal sheet are pinched at a region having the compressive stress generated in the lateral directions of the metal sheet by cooling or another region close thereto. Patent Literature 3 discloses the coexistence of bridle rolls and jet headers into a quenching bath of a continuous quench and annealing line for a steel sheet.

    Citation List


    Patent Literature



    [0005] 

    PTL 1: Japanese Unexamined Patent Application Publication No. 2011-184773

    PTL 2: Japanese Unexamined Patent Application Publication No. 2003-277833

    PTL 3: Japanese Patent JP S 5218124 B1


    Summary of Invention


    Technical Problem



    [0006] However, the technique proposed in Patent Literature 1 may possibly cause the fracture of a steel sheet because high tension is applied to the steel sheet with high temperature. Furthermore, a large thermal crown is caused in the bridle rolls which are placed upstream of the rapid quenching section and which are brought into contact with the steel sheet with high temperature. The bridle rolls are brought into contact with the steel sheet unevenly in the lateral directions of the bridle rolls. As a result, there is a problem in that the steel sheet buckles or flaws and therefore the shape of the steel sheet cannot be improved.

    [0007] As a result of verifying the technique proposed in Patent Literature 2, it has become clear that the effect of correcting a shape is small.

    [0008] The present invention has been made to solve the above problem. It is an object of the present invention to provide a method for manufacturing a metal sheet and a rapid quenching unit, the method and the rapid quenching unit being capable of effectively suppressing shape defects caused in the metal sheet during rapid quenching. Solution to Problem

    [0009] The inventors have performed intensive investigations to solve the above problem and, as a result, have obtained findings below. In a method for manufacturing a metal sheet, microstructure control inducing martensite transformation in the metal sheet during rapid cooling is used in some cases. The occurrence of martensite transformation causes the volume expansion of a microstructure and therefore a complicated, uneven irregular shape is formed. A high-tensile strength steel sheet having a martensite microstructure becomes out of shape because the highest stress acts in the steel sheet in the vicinity from the Ms temperature at which transformation expansion occurs during thermal shrinkage to the Mf temperature during rapid quenching. As used herein, the term "Ms temperature" refers to the temperature at which martensite transformation starts and the term "Mf temperature" refers to the temperature at which martensite transformation finishes.

    [0010] The inventors have devised a method for manufacturing a metal sheet according to the features of claim 1 and a rapid quenching unit according to the features of claim 3 on the basis of these findings.
    1. [1] In a method for manufacturing a metal sheet using a continuous annealing line including a rapid quenching unit for cooling the metal sheet by immersing the metal sheet in a liquid, the metal sheet in rapid quenching is pinched between a pair of pinch rolls placed in the liquid in the range where the temperature of the metal sheet is from (TMs + 150) (°C) to (TMf - 150) (°C), TMs (°C) is a Ms temperature at which the martensite transformation of the metal sheet starts, TMf (°C) is a Mf temperature at which the martensite transformation thereof finishes.
    2. [2] In the method for manufacturing the metal sheet specified in Item [1], the pinch position of each pinch roll is set on the basis of a feed rate, a thickness, and a quenching start temperature of the metal sheet.
    3. [3] In the method for manufacturing the metal sheet specified in Item [1] or [2], a distance d (mm) from a water surface to a rotation center of the pinch roll is given by a formula below.

      TMs (°C) is the Ms temperature of the metal sheet,

      TMf (°C) is Mf temperature of the metal sheet,

      v (m/s) is the threading speed,

      t (mm) is a thickness of the metal sheet,

      T (°C) is a quenching start temperature, and

      d (mm) is the distance from the water surface to the rotation center of each pinch roll.

    4. [4] In the method for manufacturing the metal sheet specified in any one of Items [1] to [3], the rapid quenching unit includes water ejecting devices for ejecting cooling water to the front surface and back surface of the metal sheet and a pair of the pinch rolls pinch the metal sheet placed between the metal sheet and the water ejecting devices.
    5. [5] A rapid quenching unit for cooling a high-temperature metal sheet by immersing the metal sheet in a liquid includes a pair of pinch rolls. Supposing that the Ms temperature of the metal sheet is TMs (°C) and the Mf temperature thereof is TMf (°C), the pinch rolls pinch the metal sheet in the range where the temperature of the metal sheet is from (TMs + 150) (°C) to (TMf - 150) (°C) .
    6. [6] The rapid quenching unit specified in Item [5] includes water ejecting devices for ejecting cooling water to the front surface and back surface of the metal sheet. The pinch rolls are placed between the metal sheet and the water ejecting devices.

    Advantageous Effects of Invention



    [0011] In accordance with a method for manufacturing a metal sheet and a rapid quenching unit according to the present invention, shape defects caused in the metal sheet during rapid quenching can be effectively suppressed.

    Brief Description of Drawings



    [0012] 

    [Fig. 1] Fig. 1 is an illustration of a rapid quenching unit according to an embodiment of the present invention.

    [Fig. 2] Fig. 2 is a graph showing the relationship between the position of the rotation center of a pinch roll and the camber of a steel sheet after the pinch roll passed in an example.

    [Fig. 3] Fig. 3 is an illustration showing the camber used in Fig. 2.

    [Fig. 4] Fig. 4 is a graph showing the relationship between the feed rate v (m/s) of a steel sheet and the distance d (mm) from the water surface to the rotation center of a pinch roll.


    Description of Embodiments



    [0013] Embodiments of the present invention are described below with reference to the attached drawings.

    [0014] Fig. 1 is an illustration of a rapid quenching unit according to an embodiment of the present invention. The rapid quenching unit is used in a cooling line placed on the delivery side of a soaking zone of a continuous annealing furnace. In Fig. 1, a pair of seal rolls 3 placed at an outlet of the soaking zone of the continuous annealing furnace is shown. The rapid quenching unit includes a water tank 1 filled with water 2 (liquid); water ejecting devices 4, placed in the water tank 1, for applying cooling water to a metal sheet 5 to cool the metal sheet 5 to the water temperature; and a sink roll 6 which immerses the metal sheet 5 in the water tank 1 and which changes the transport direction of the metal sheet 5.

    [0015] The water ejecting devices 4 are partly placed in the water tank 1. The water ejecting devices 4 are arranged on the front side and back side of the metal sheet 5 with a predetermined spaced therebetween. The water ejecting devices 4, which are arranged on the front and back sides thereof, each include nozzles 4a extending in a lateral direction of the metal sheet 5. The nozzles 4a are arranged in the transport direction of the metal sheet 5. The water ejecting devices 4 eject cooling water from the nozzles 4a to the metal sheet 5 to rapidly cool the metal sheet 5.

    [0016] The metal sheet 5 that is below the water surface is thermally shrunk by rapidly cooling the metal sheet 5 with cooling water. In particular, when the temperature of the metal sheet 5 is reduced to the Mf temperature that is the temperature at which martensite transformation finishes from the Ms temperature that is the temperature at which martensite transformation starts, rapid thermal shrinkage and transformation expansion occur in the metal sheet 5 together to maximize the stress acting in the metal sheet 5 and the metal sheet 5 becomes out of shape.

    [0017] Therefore, in the present invention, supposing that the Ms temperature of the metal sheet is TMs (°C) and the Mf temperature thereof is TMf (°C), pinch rolls 7 pinching the metal sheet 5 in rapid quenching are placed below the water surface in the range where the temperature of the metal sheet 5 is from (TMs + 150) (°C) to (TMf - 150) (°C). In particular, a pair of the pinch rolls 7 are placed in spaces between the metal sheet 5 and the nozzles 4a of the water ejecting devices 4 so as to pinch both sides of the metal sheet 5. The reason why the position of each pinch roll 7 is in a region from the Ms temperature plus 150°C to the Mf temperature minus 150°C is that the camber was sufficiently reduced in this range in an example described below with reference to Fig. 4.

    [0018] The Ms temperature and the Mf temperature can be calculated from the composition of the metal sheet 5.

    [0019] A pair of the pinch rolls 7 are preferably placed such that the center axes thereof are misaligned in the transport direction of the metal sheet 5. Placing the pinch rolls 7 such that the center axes thereof are misaligned enables the pinching force of the metal sheet 5 to be increased, thereby enabling the shape correction force to be increased.

    [0020] The preferred position of each pinch roll 7 is preferably set on the basis of the sheet feed rate v (m/s), the sheet thickness t (mm), and the quenching start temperature T (°C). Supposing that the cooling rate is 1,500/t (°C/s), the position from the water surface that the temperature of the metal sheet 5 is (TMs + 150) (°C) can be given by Formula (1). Incidentally, the cooling rate is a value determined depending on the sheet thickness or the like. When the sheet thickness is 1 mm, the cooling rate is 1,000/t to 2,000/t (°C/s). Therefore, in the present invention, the cooling rate is 1,500/t (°C/s), which is an intermediate value. The cooling rate can be appropriately set depending on the sheet thickness and the like.
    [Math. 2]



    [0021] Likewise, the position from the water surface that the temperature of the metal sheet 5 is (TMf - 150) (°C) can be given by Formula (2).
    [Math. 3]



    [0022] Thus, the distance d (mm) from the water surface to the rotation center of each pinch roll 7 is preferably given by Formula (3).
    [Math. 4]



    [0023] The rotation center of the pinch roll 7 corresponds to the pinch position of the metal sheet 5 pinched between the pinch rolls 7. Referring to Fig. 1, the two pinch rolls 7, which pinch the metal sheet 5, are placed so as to be misaligned in the transport direction of the metal sheet 5. The position of each pinch roll 7 preferably satisfies the above-mentioned range.

    [0024] In the present invention, since the pinch rolls 7, which can pinch the metal sheet 5, are placed below the water surface in the range where the temperature of the metal sheet 5 is from the Ms temperature to the Mf temperature, the shape of the metal sheet 5 can be effectively corrected in such a manner that the metal sheet 5 is pinched at a position at which the highest stress acts in the metal sheet 5.

    [0025] As described above, the present invention is intended to reduce a complicated, uneven irregular shape that is caused when martensite transformation occurs during the rapid cooling of a steel sheet to expand the volume of a microstructure. The present invention is preferably applied to a method for manufacturing a high-strength cold-rolled steel sheet (Haiten).

    [0026] In particular, the present invention is preferably applied to a method for manufacturing a steel sheet with a tensile strength of 580 MPa or more. The upper limit of the tensile strength is not particularly limited and is, for example, 1,600 MPa or less. An example of the composition of the high-strength cold-rolled steel sheet is as follows: C is 0.04% to 0.220%, Si is 0.01% to 2.00%, Mn is 0.80% to 2.80%, P is 0.001% to 0.090%, S is 0.0001% to 0.0050%, and sol. Al is 0.005% to 0.065% on a mass basis, the remainder being Fe and inevitable impurities. At least one or more of Cr, Mo, Nb, V, Ni, Cu, and Ti are 0.5% or less as required. B and/or Sb is 0.01% or less as required.

    EXAMPLE



    [0027] A high-tensile strength cold-rolled steel sheet having a thickness of 1.0 mm, a width of 1,000 mm, and a tensile strength of about 1,470 MPa was manufactured at a feed rate of 1.0 m/s using a rapid quenching unit shown in Fig. 1. The quenching start temperature T of the steel sheet is 740°C, the quenching finish temperature thereof is 50°C, the Ms temperature TMs thereof is 350°C, and the Mf temperature TMf thereof is 250°C.

    [0028] Fig. 2 shows the relationship between the distance from the water surface to the rotation center of each pinch roll and the camber of the steel sheet after the roll passed. Fig. 3 shows the definition of the camber. In particular, the camber was defined as the highest position when the steel sheet was placed on the horizontal.

    [0029] In Fig. 2, the horizontal axis represents the distance from the water surface of a water tank 1 to the pinch roll 7 and the vertical axis represents the camber of the steel sheet. The steel sheet is pinched between the pinch rolls 7 at a position which is 200 mm to 400 mm below the water surface and at which the temperature of the steel sheet is from the Ms temperature to the vicinity of the Mf temperature, whereby the camber is reduced to 10 mm or less.

    [0030] In order to investigate the influence of the feed rate of a steel sheet, high-tensile strength cold-rolled steel sheets having a thickness of 1.0 mm, a width of 1,000 mm, and a tensile strength of about 1,470 MPa were manufactured at a feed rate of 1.0 m/s, 1.5 m/s, or 2.0 m/s using the rapid quenching unit shown in Fig. 1. The quenching start temperature is 740°C, the quenching finish temperature is 50°C, the Ms temperature TMs is 350°C, and the Mf temperature TMf is 250°C.

    [0031] Fig. 4 is a graph showing the relationship between the feed rate v (m/s) of each steel sheet and the distance d (mm) from the water surface to the rotation center of each roll. In a combination of the feed rate v (m/s) of the steel sheet and the distance d (mm) from the water surface to the rotation center of the roll, the camber of the steel sheet was measured. A camber of less than 10 mm was rated "○" and a camber of 10 mm or more was rated "×".

    [0032] When the relationship between the Ms temperature TMs of a steel sheet, the Mf temperature TMf thereof, the feed rate v (m/s) thereof, the thickness t (mm) thereof, the quenching start temperature T (°C) thereof, and the distance d (mm) from the water surface to each pinch roll 7 was in the range vt(T - TMs - 150)/1.5 ≤ d ≤ vt(T - TMf + 150)/1.5, a good result was obtained.

    [0033] In this embodiment, an apparatus for water-cooling a steel sheet has been exemplified. The present invention is not necessarily limited to this. The technical concept of the present invention is broad, can be used to cool all metal sheets other than steel sheets, and can be applied to all rapid quenching units other than water-cooling units.

    Reference Signs List



    [0034] 
    1
    Water tank
    2
    Water
    3
    Seal rolls
    4
    Water ejecting devices
    4a Nozzles
    5
    Metal sheet
    6
    Sink roll
    7
    Pinch rolls



    Claims

    1. A method for manufacturing a metal sheet (5) using a continuous annealing line including a rapid quenching unit for cooling the metal sheet by immersing the metal sheet in a liquid (2), wherein the metal sheet in rapid quenching is pinched between a pair of pinch rolls (7) placed in the liquid (2) in a range where a temperature of the metal sheet is from (TMs + 150) (°C) to (TMf - 150) (°C),
    TMs (°C) is a Ms temperature at which the martensite transformation of the metal sheet starts,
    TMf (°C) is a Mf temperature at which the martensite transformation thereof finishes; characterised in that:
    the rapid quenching unit includes water ejecting devices (4) for ejecting cooling water to a front surface and back surface of the metal sheet (5) and a pair of the pinch rolls (7) pinch the metal sheet said pinch rolls are placed between the metal sheet and the water ejecting devices for correcting the shape of the metal sheet (5).
     
    2. The method for manufacturing the metal sheet according to Claim 1, wherein a pinch position of the pair of pinch rolls is set on the basis of a threading speed, a thickness, and a quenching start temperature of the metal sheet, such that a distance d (mm) from a surface of the liquid (2) to a rotation center of each pinch roll (7) is given by the following formula:

    TMs (°C) is the Ms temperature of the metal sheet,

    TMf (°C) is Mf temperature of the metal sheet,

    v (m/s) is the threading speed of the metal sheet,

    t (mm) is a thickness of the metal sheet,

    T (°C) is a quenching start temperature, and

    d (mm) is the distance from the surface of the liquid to the rotation center of each pinch roll.


     
    3. A rapid quenching unit for cooling a high-temperature metal sheet (5) by immersing the metal sheet in a liquid, comprising a pair of pinch rolls (7), wherein the pinch rolls pinch the metal sheet in the range where the temperature of the metal sheet is from (TMs + 150) (°C) to (TMf - 150) (°C),
    TMs (°C) is a Ms temperature of the metal sheet, and
    TMf (°C) is a Mf temperature thereof; characterised in that:
    the rapid quenching unit includes water ejecting devices (4) for ejecting cooling water to a front surface and back surface of the metal sheet (5) and the pair of pinch rolls (7) are placed between the metal sheet and the water ejecting devices (4) for correcting the shape of the metal sheet (5).
     


    Ansprüche

    1. Verfahren zum Herstellen eines Metallblechs (5) unter Benutzung eine Durchlaufglühlinie, die eine Schnellabschreckeinheit zum Kühlen des Metallblechs durch Eintauchen des Metallblechs in eine Flüssigkeit (2) enthält, wobei das Metallblech beim Schnellabschrecken zwischen ein Paar Klemmrollen (7), die in der Flüssigkeit (2) angeordnet sind, in einem Bereich eingeklemmt wird, in dem eine Temperatur des Metallblechs von (TMs + 150) (°C) bis (TMf - 150) (°C) reicht,
    wobei TMs (°C) eine Ms-Temperatur ist, auf der die Martensitumwandlung des Metallblechs beginnt,
    wobei TMf (°C) eine Mf-Temperatur ist, auf der die Martensitumwandlung davon abschließt; dadurch gekennzeichnet, dass:
    die Schnellabschreckeinheit Wasserausstoßvorrichtungen (4) zum Ausstoßen von Kühlwasser zu einer Vorderfläche und Rückfläche des Metallblechs (5) enthält und ein Paar Klammrollen (7) das Metallblech einklemmen, wobei die Klemmrollen zwischen dem Metallblech und den Wasserausstoßvorrichtungen zum Korrigieren der Form des Metallblechs (5) angeordnet sind.
     
    2. Verfahren zum Herstellen eines Metallblechs nach Anspruch 1, wobei eine Klemmposition des Paars Klemmrollen derart basierend auf einer Einziehgeschwindigkeit, einer Stärke und einer Abschreckstarttemperatur des Metallblechs eingestellt wird, dass ein Abstand d (mm) von einer Oberfläche der Flüssigkeit (2) zu einem Drehzentrum jeder Klemmrolle (7) durch die folgende Formel gegeben ist:

    wobei TMs (°C) die Ms-Temperatur des Metallblechs ist,

    TMf (°C) die Mf-Temperatur des Metallblechs ist,

    v (m/s) die Einziehgeschwindigkeit des Metallblechs ist,

    t (mm) eine Stärke des Metallblechs ist,

    T (°C) eine Abschreckstarttemperatur ist, und

    d (mm) der Abstand von der Oberfläche der Flüssigkeit zum Drehzentrum jeder Klemmrolle ist.


     
    3. Schnellabschreckeinheit zum Kühlen eines Hochtemperaturmetallblechs (5) durch Eintauchen des Metallblechs in eine Flüssigkeit, umfassend ein Paar Klemmrollen (7), wobei die Klemmrollen das Metallblech in dem Bereich einklemmen, in dem die Temperatur des Metallblechs von (TMs + 150) (°C) bis (TMf - 150) (°C) reicht,
    wobei TMs (°C) eine Ms-Temperatur des Metallblechs ist, und
    wobei TMf (°C) eine Mf-Temperatur davon ist; dadurch gekennzeichnet, dass:
    die Schnellabschreckeinheit Wasserausstoßvorrichtungen (4) zum Ausstoßen von Kühlwasser zu einer Vorderfläche und Rückfläche des Metallblechs (5) enthält und das Paar Klammrollen (7) zwischen dem Metallblech und den Wasserausstoßvorrichtungen (4) zum Korrigieren der Form des Metallblechs (5) angeordnet ist.
     


    Revendications

    1. Procédé de fabrication d'une tôle métallique (5) à l'aide d'une ligne de recuit en continu comprenant une unité de trempe rapide pour refroidir la tôle métallique en immergeant la tôle métallique dans un liquide (2), dans lequel la tôle métallique en cours de trempe rapide est pincée entre une paire de rouleaux de pincement (7) placés dans le liquide (2) dans une plage où une température de la tôle métallique est de (TMs + 150) (°C) à (TMf - 150) (°C),
    TMs (°C) est une température Ms à laquelle commence la transformation martensitique de la tôle métallique,
    TMf (°C) est une température Mf à laquelle se termine la transformation martensitique de celle-ci ; caractérisé en ce que
    l'unité de trempe rapide comprend des dispositifs d'éjection d'eau (4) pour éjecter de l'eau de refroidissement vers une surface avant et une surface arrière de la tôle métallique (5) et une paire de rouleaux de pincement (7) pincent la tôle métallique, lesdits rouleaux de pincement étant placés entre la tôle métallique et les dispositifs d'éjection d'eau pour corriger la forme de la tôle métallique (5) .
     
    2. Procédé de fabrication de la tôle métallique selon la revendication 1, dans lequel une position de pincement de la paire de rouleaux de pincement est réglée sur la base d'une vitesse d'insertion, d'une épaisseur et d'une température de début de trempe de la tôle métallique, de sorte qu'une distance d (mm) d'une surface du liquide (2) à un centre de rotation de chaque rouleau de pincement (7) est donnée par la formule suivante :

    TMs (°C) est la température Ms de la tôle métallique,

    TMf (°C) est la température Mf de la tôle métallique,

    v (m/s) est la vitesse d'insertion de la tôle métallique,

    t (mm) est une épaisseur de la tôle métallique,

    T (°C) est une température de commencement de trempe, et

    d (mm) est la distance de la surface du liquide au centre de rotation de chaque rouleau de pincement.


     
    3. Unité de trempe rapide pour refroidir une tôle métallique haute température (5) en immergeant la tôle métallique dans un liquide, comprenant une paire de rouleaux de pincement (7), dans laquelle les rouleaux de pincement pincent la tôle métallique dans la plage où la température de la tôle métallique est de (TMs + 150) (°C) à (TMf - 150) (°C),
    TMs (°C) est une température Ms de la tôle métallique, et
    TMf (°C) est une température Mf de celle-ci ; caractérisée en ce que
    l'unité de trempe rapide comprend des dispositifs d'éjection d'eau (4) pour éjecter de l'eau de refroidissement vers une surface avant et une surface arrière de la tôle métallique (5) et une paire de rouleaux de pincement (7) sont placés entre la tôle métallique et les dispositifs d'éjection d'eau (4) pour corriger la forme de la tôle métallique (5).
     




    Drawing











    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description