EP0080932B1 - Method and device for the controlled cooling of sheets - Google Patents

Method and device for the controlled cooling of sheets Download PDF

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Publication number
EP0080932B1
EP0080932B1 EP19820402134 EP82402134A EP0080932B1 EP 0080932 B1 EP0080932 B1 EP 0080932B1 EP 19820402134 EP19820402134 EP 19820402134 EP 82402134 A EP82402134 A EP 82402134A EP 0080932 B1 EP0080932 B1 EP 0080932B1
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EP
European Patent Office
Prior art keywords
temperature
cooling
cooling fluid
theoretical
case
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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.)
Expired
Application number
EP19820402134
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German (de)
French (fr)
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EP0080932A1 (en
Inventor
Stéphane Viannay
Jack Sebbah
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USINOR SA
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Union Siderurgique du Nord et de lEst de France SA USINOR
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Publication of EP0080932A1 publication Critical patent/EP0080932A1/en
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/62—Quenching devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
    • B21B45/0203—Cooling
    • B21B45/0209—Cooling devices, e.g. using gaseous coolants
    • B21B45/0215—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes
    • B21B45/0218—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes for strips, sheets, or plates

Definitions

  • the present invention relates to a process for carrying out the controlled cooling of sheets in order to obtain a perfectly defined crystalline structure of the metal composing it.
  • a method of cooling sheets coming out of rolling mills is known in particular, making it possible to reach high cooling rates with a view to treating sheets of substantial thickness without prohibitively increasing the powers involved. This method and the machine for its implementation are described in FR-A-2 223 096.
  • the heated sheet metal plate is presented horizontally at the entrance to an enclosure in which it is driven in a uniform translational movement by means of rollers.
  • a water blade of constant height and driven by a high speed circulates on both sides of the plate to dissipate the heat from the sheet.
  • each surface element of the metal is in contact, inside the enclosure, with a mass of fluid regularly renewed.
  • the corresponding heat flux exchanged between the plate and the water is higher the higher the flow speed of the water; it is possible thanks to this process to extract a heat flux of the order of 3 x 10 6 W / m 2 .
  • This value corresponds to the core cooling rate of 30 ° C / s of a 30 mm thick plate.
  • the cooling rates achievable according to the process described in the aforementioned patent application appear to be entirely compatible for carrying out, for example, the martensitic quenching of a steel sheet at manganese carbon containing approximately 0.17% carbon and 1/4% manganese, with no other alloying element. It goes without saying that the application of this same treatment to steels containing small amounts of additions, for example, molybdenum, nickel or boron whose presence has the effect of increasing the quenchability, will also produce a structure martensitic.
  • the process defined in the aforementioned patent application does not make it possible to directly obtain the desired final structure of a metal, for example of a steel of given composition.
  • the cooling operation generally results in the martensitic quenching of the metal and an tempering operation, characterized for steel by maintaining a suitable duration at a temperature below 710 ° C., must follow the operation of cooling.
  • studies relating to cooling transformations show that the cooling rate determines the structure of a steel of given composition.
  • Certain phases, in particular bainite, or mixture of phases, bainite and perlite with very fine grains, characterized by good mechanical properties of toughness and ductility, can be sought in the case of suitable grades of steel.
  • the object of the invention is therefore to provide a method and a cooling machine of the aforementioned type, making it possible to adjust and control the cooling rate of the sheet metal plates according to values determined as a function of the desired structures.
  • the subject of the invention is a method for controlling the cooling of a sheet in order to give it a predetermined crystal structure, according to which the sheet to be cooled is passed through an enclosure containing a mass of cooling fluid. regularly renewed, the flow rate of which is adjusted and the temperature of which is measured, characterized in that, as a function of the thickness of the sheet and the desired cooling rate, a theoretical heat flux is determined which must be exchanged between the sheet and the coolant; a theoretical flow speed of the fluid on the sheet is calculated as a function of the temperature of arrival of the cooling fluid and of the theoretical heat flow; the flow rate of the cooling fluid is adjusted as a function of the calculated theoretical speed; a theoretical temperature of the cooling fluid is determined, as a function of the heat flux; this theoretical temperature is compared with the measured temperature, and the inlet temperature of the cooling fluid is regulated as a function of this theoretical temperature.
  • the invention also relates to an installation for implementing the method defined above, said installation comprising a machine composed of an enclosure comprising means for circulating a cooling fluid which moves roughly parallel to the sheet metal, a cooling tank, means for injecting the cooling fluid contained in the tank inside said enclosure and means for discharging the cooling fluid after it has passed through the cooling enclosure, a device for controlling the cooling fluid flow rate and a device for measuring the temperature of the cooling fluid, characterized in that it comprises a member for calculating the theoretical heat flux and a member for calculating the theoretical speed, connected to the calculating member of the theoretical heat flow and to the temperature measurement device, a device for regulating the temperature of the coolant introduced into the girdle, comprising two inputs connected respectively to the device for measuring the temperature of the coolant and to a device providing a theoretical value of the temperature of the coolant, and an output connected to at least one solenoid valve inserted in a circuit d cold water supply to said cooling tank.
  • the invention comprises means for regulating the pressure of the fluid inside the enclosure.
  • the installation shown in FIG. includes a cooling machine 1, a cooling tank 2, and a control and regulation device 3.
  • the cooling machine 1 is of the general type described in patent application n ° 2 223 096.
  • This machine consists of a series of support and guide rollers 4a, 4b to 8a, 8b.
  • the essential elements of the machine arranged symmetrically on either side of the mean plane of the sheet will be designated by the same reference numerals assigned with index a for the upper elements and b for the lower elements.
  • the machine comprises a casing or metal container 9 which extends between the guide rollers 10a, 10b, and surrounds these rolls 11a, 11b.
  • the flat walls 10a, 10b are substantially parallel and are separated by an interval greater than the thickness of the sheet, so as to delimit with the latter two chambers or channels 12a, 12b with a thickness c.
  • Water circulation means comprise at least one supply conduit 13a, 13b, 14a, 14b extending for example over the entire length of the rollers 5 a, 5 b, 7 a, 7 b and at least one exhaust duct 15 a , 15 b , 16 a , 16 b , 17 a , 17 b also extending over the entire length of the rollers 4 a , 4 b , 6 8 , 6 b and 8 a , 8 b .
  • the cooling tank 2 contains the cooling water; on its flanks are provided orifices 18, 19 to allow the exit of the cooling water intended for the machine 1 and water inlet orifices 20, 21 to recover the water which returns from the cooling machine .
  • the orifices 18 and 19 of water outlet of the tray 2 are connected to the supply conduits 13a, 13b, 14a, 14b of the machine through conduits 23a, 23b through feed pumps 24a, B.
  • the water inlet orifices 20, 21 of tank 2 are connected to the discharge conduits 15 a , 15 b , 16 a , 16 b , 17 a , 17 b by conduits 25a, 25 b through electro -Vannes 26a, 26 b.
  • a solenoid valve 27 mounted on line 28 ensures the supply of cold water to the tank.
  • the command and control device 3 essentially consists of a computer which can be of the digital, analog or hybrid type, the latter type being suitable for carrying out processing on both digital and analog quantities.
  • the control and regulating device 3 shown is of hybrid type, it assures the control and regulation of the flow pumps 24a, 24b and solenoid valves 26a, 26b and 27. It is connected by its inputs 1 1 1 2 to a display table 29 of the set values R relating to the desired cooling speed and e relating to the thickness of the sheet metal entering the cooling machine.
  • the setpoints R and e are transmitted in binary coded form to the inputs I 1 and I 2 of the device 3.
  • the input 1 3 is connected to a sensor 30 of the atmospheric pressure P °.
  • Outputs 1 4 and 1 5 transmit the control commands 24a and pump 24b.
  • the inlet 1 6 receives, from a thermometric probe 32 disposed inside the tank 2, the value of the temperature of the coolant.
  • This temperature value is received in the form of an analog signal and in the form of a binary word of several bits.
  • the outputs I 7 to I 9 provide the respective controls for the solenoid valves 27, 26 b and 26a.
  • the input I 10 receives the value of the relative pressure P of the water at the input of enclosure 9 of the machine and transmitted by a pressure sensor 33.
  • This device comprises a member 34 for calculating the value of the heat flux ⁇ exchanged between the sheet metal T and the cooling water, a member 35 for calculating the speed of the cooling fluid necessary to cool the sheet metal under the desired conditions , a member 36 for controlling the flow rate of the pumps 24 a and 24 b , a member 37 for regulating the temperature of the water in the tank 2 and a member 38 for regulating the pressure inside the enclosure 9 cooling.
  • the member 34 is constituted by a programmable read only memory which contains a table A 1 giving the values of the heat flux ⁇ corresponding to different set values R and e.
  • This table A 1 can be determined from a theoretical calculation taking into account the thickness c of the cooling water sheet circulating above and below the sheet to be cooled, and the boundary thermal conditions, in particular the heat flow exchanged on the surface of the sheet. These calculations involving the heat equations, lead to complicated formulas and it is preferable to build the table A 1 directly from tests carried out on several sheet thicknesses and for different cooling rates.
  • the member 35 is also constituted by a programmable read only memory which contains a table A 2 giving the values of the cooling rate corresponding to the different values of thermal flux stored in the memory of the member 34 and to different temperature values 0 of cooling water.
  • This table A 2 is determined from the relation which links the heat flow 0 exchanged, to the flow speed of the cooling water and which is given by the formula: where ⁇ ( ⁇ ) is a coefficient which only depends on the temperature of the cooling water.
  • the member 36 is also constituted by a programmable read-only memory which contains in memory a table A 3 giving the values of the flow rate of the pumps as a function of the values of the speed of the cooling water read in the memory of the member 35.
  • the unit 35 also contains a digital-analog converter, not shown, connected to the output of its memory, necessary for delivering the analog signals for controlling the pumps 24a and 24b.
  • the memory member 34 is connected by its two addressing inputs to it inputs and 1 2 of the device 3 and by its output, on the one hand, to a memory addressing input of the member 35 and , on the other hand, at the input of a multiplication circuit 39 located in the regulating member 37.
  • the memory of the member 35 is connected on its second addressing input to the input 1 6 of the device 3 receiving the binary word transmitted by the temperature probe 32.
  • the output of the member 35 is connected to the addressing input of the memory of the member 36 and the output of the member 36 is connected to the outputs 1 4 and 1 5 of the computer 3.
  • the temperature of the cooling water must naturally be between these two values.
  • 0 M and 0 m are determined from formula (I) for the respective values of ⁇ 0 and ⁇ c and for values V of the speed of the water blade, knowing that the speed V of the blade must be higher than a critical speed V c for the coolant to fill the enclosure.
  • This critical speed corresponds to a dynamic pressure, expressed in water height, equal to the thickness of the tunnel.
  • the circuit 39 for multiplication by a constant is constituted in a known manner by a digital / analog converter composed of a network of resistance cells (R, 2R) in ⁇ whose supply voltage is varied as a function of the value of the constant q.
  • the summing circuit 43 is connected by an input to the output of the circuit 39 and by its other input to the cursor of the potentiometer 40.
  • the summing circuit 44 is connected by an input to the output of the circuit 43 and by its other input to the cursor of the potentiometer 41.
  • the subtraction circuit 45 is connected by an input to the output of the circuit 43 and by its other input to the cursor of potentiometer 42.
  • the comparator 46 has two inputs, one is connected to the input terminal 1 6 of the device 3 to receive the analog signal transmitted by the temperature probe 32 and the other is connected to the output of the circuit 44.
  • the comparator 47 also has two inputs, one is connected to the input terminal 1 6 of the device 30 to receive the analog signal transmitted by the temperature probe 32, the other is connected to the output of the circuit 45.
  • the outputs of the comparators 46 and 47 are connected to two respective inputs of the member 50.
  • the regulating member 38 consists of the potentiometer 51, the summing circuit 52 and the comparator 53.
  • the circuit 52 has two inputs, one of which is connected to the terminal 1 3 of the member 3 and the other is connected to potentiometer cursor 51.
  • Comparator 53 also has two inputs, one is connected to the output of circuit 52 and the other is connected to the input terminal I 10 of the device 3. The output of the comparator 53 is connected to the output terminals 1 8 and I 9 of the device 3.
  • Fig. 2 also show the devices for displaying the reference values R and e of the display panel 29.
  • These devices are constituted by analog digital encoders 54 and 55 whose parallel outputs are connected respectively to the input terminals I 1 and I 2 of the device 3.
  • These coders can consist of simple switch registers whose state represents for example the binary-coded decimal value of the set value.
  • the atmospheric pressure sensor 30 connected to terminal 1 3 of the device 3 and the pressure sensor 33 connected to terminal I 10 .
  • the operation of the cooling installation is as follows.
  • the operator has the manufacturing data which are the thickness e of the sheet and the cooling rate R corresponding to the desired structures of the metal. These two data are displayed on the switch registers 55 and 54 of the display panel 29. They are introduced on the input terminals I 1 and I 2 of the command and regulation device 3 in the direction of the addressing inputs. of the memory of the member 34.
  • the regulating device 37 regulates the temperature of the water in the tank 2.
  • the operating temperature relative to the cooling water is determined by the summing circuit 43 and the multiplication circuit by a constant 39.
  • the circuit 39 delivers an output quantity q ⁇ ⁇ which is proportional to the quantity ⁇ of the heat flux exchanged between the sheet metal plate and the cooling water.
  • This quantity q - 0 is added to the aforementioned constant p displayed inside the calculating member 37 on the potentiometer 40.
  • the permitted limits for variation of the temperature 0f are displayed on the potentiometers 41 and 42, the potentiometer 41 delivering a value + ⁇ and the potentiometer 42 delivering a value - ⁇ .
  • the value + ⁇ is added to the operating temperature ⁇ f in the summing circuit 44 which outputs a value ⁇ f + ⁇ .
  • This theoretical value ⁇ f + ⁇ is compared with the temperature of the water measured in the tank 2, by the comparator 46, the output of which controls the control member 50 of the water supply solenoid valve 27 when the 0 temperature of the measured water is higher than the calculated value ⁇ f + ⁇ .
  • the subtraction circuit 45 subtracts from the calculated value ⁇ , the value - ⁇ transmitted by the potentiometer 42.
  • the result 0f - ⁇ obtained is compared to the value ⁇ of the water measured in the tank 2 to l using comparator 47 to close the solenoid valve 27 when the measured water temperature is lower than the calculated value ⁇ f - ⁇ .
  • the regulation circuit 38 makes it possible to act against the pressure losses which take place in the return circuit and which are due to the reduction in the rate of injection of the cooling water by the pumps.
  • the summation circuit 52 adds the value of the atmospheric pressure Po sensed by the pressure sensor 30 to a value e displayed on the potentiometer 51 and transmits the result of the summation Po + ⁇ to the input of the comparator 53 which compares this value at the pressure value P measured by the pressure sensor 33 inside the cooling enclosure 9.
  • the comparator 53 When the pressure P appears for the comparator 53 greater than the pressure Po + e, the latter controls the opening of the electro -return valves 26a, 26b . By cons if the pressure P is equal to or less than the pressure Po + ⁇ the comparator 53 controls the closing of the solenoid valves 26a and back 26b, so as to increase the pressure P within the enclosure cooling.
  • the temperature regulation device keeps the water in the tank at a constant temperature, which allows firstly, to maintain at a constant level the heat flow exchanged between the sheet and the cooling water and secondly, to keep the vapor pressure in the siphon formed by the discharge conduits 16a, 17a at a constant level, thus avoiding the defusing of the latter and the flow of water through the ends of the machine.

Description

La présente invention concerne un procédé pour effectuer le refroidissement contrôlé de tôles en vue d'obtenir une structure cristalline parfaitement définie du métal la composant.The present invention relates to a process for carrying out the controlled cooling of sheets in order to obtain a perfectly defined crystalline structure of the metal composing it.

Elle concerne également une installation pour la mise en oeuvre de ce procédé.It also relates to an installation for the implementation of this process.

On connaît notamment un procédé de refroidissement de tôles sortant de laminoirs permettant d'atteindre des vitesses de refroidissement élevées en vue de traiter des tôles d'épaisseur importante sans pour autant augmenter de façon prohibitive les puissances mises en jeu. Ce procédé et la machine pour sa mise en oeuvre sont décrits dans FR-A-2 223 096.A method of cooling sheets coming out of rolling mills is known in particular, making it possible to reach high cooling rates with a view to treating sheets of substantial thickness without prohibitively increasing the powers involved. This method and the machine for its implementation are described in FR-A-2 223 096.

Selon ce procédé, dès la fin du laminage, la plaque de tôle chauffée est présentée horizontalement à l'entrée d'une enceinte dans laquelle elle est entraînée d'un mouvement uniforme de translation au moyen de rouleaux. Simultanément, une lame d'eau de hauteur constante et animée d'une grande vitesse circule sur les deux faces de la plaque pour dissiper la chaleur de la tôle.According to this process, at the end of the rolling, the heated sheet metal plate is presented horizontally at the entrance to an enclosure in which it is driven in a uniform translational movement by means of rollers. Simultaneously, a water blade of constant height and driven by a high speed circulates on both sides of the plate to dissipate the heat from the sheet.

Ainsi, chaque élément de surface du métal est en contact, à l'intérieur de l'enceinte, avec une masse de fluide régulièrement renouvelée. Le flux thermique correspondant échangé entre la plaque et l'eau est d'autant plus élevé que la vitesse d'écoulement de l'eau est plus grande ; il est possible grâce à ce procédé d'extraire un flux thermique de l'ordre de 3 x 106 W/m2. Cette valeur correspond à la vitesse de refroidissement à coeur de 30 °C/s d'une plaque épaisse de 30 mm. D'après les études et expériences faites par la Demanderesse, les vitesses de refroidissement réalisables selon le procédé décrit dans la demande de brevet précité, apparaissent tout à fait compatibles pour réaliser, par exemple, la trempe martensitique d'une tôle d'acier au carbone manganèse contenant environ 0,17 % de carbone et 1/4 % de manganèse, sans autre élément d'alliage. Il va de soi que l'application de ce même traitement à des aciers contenant des faibles quantités d'additions, par exemple, de molybdène, de nickel ou de bore dont la présence a pour effet d'augmenter la trempabilité, produira également une structure martensitique.Thus, each surface element of the metal is in contact, inside the enclosure, with a mass of fluid regularly renewed. The corresponding heat flux exchanged between the plate and the water is higher the higher the flow speed of the water; it is possible thanks to this process to extract a heat flux of the order of 3 x 10 6 W / m 2 . This value corresponds to the core cooling rate of 30 ° C / s of a 30 mm thick plate. According to the studies and experiments made by the Applicant, the cooling rates achievable according to the process described in the aforementioned patent application, appear to be entirely compatible for carrying out, for example, the martensitic quenching of a steel sheet at manganese carbon containing approximately 0.17% carbon and 1/4% manganese, with no other alloying element. It goes without saying that the application of this same treatment to steels containing small amounts of additions, for example, molybdenum, nickel or boron whose presence has the effect of increasing the quenchability, will also produce a structure martensitic.

Toutefois, le procédé défini dans la demande de brevet précitée ne permet pas d'obtenir directement la structure finale désirée d'un métal, par exemple d'un acier de composition donnée. En effet, l'opération de refroidissement se traduit généralement par la trempe martensitique du métal et une opération de revenu, caractérisée pour l'acier par un maintien de durée convenable à une température inférieure à 710 °C, doit succéder à l'opération de refroidissement. Or, les études relatives aux transformations en refroidissement montrent que la vitesse de refroidissement détermine la structure d'un acier de composition donnée. Certaines phases, notamment bainite, ou mélange de phases, bainite et perlite à grains très fins, caractérisées par de bonnes propriétés mécaniques de ténacité et de ductilité, peuvent être recherchées dans le cas de nuances convenables d'acier.However, the process defined in the aforementioned patent application does not make it possible to directly obtain the desired final structure of a metal, for example of a steel of given composition. Indeed, the cooling operation generally results in the martensitic quenching of the metal and an tempering operation, characterized for steel by maintaining a suitable duration at a temperature below 710 ° C., must follow the operation of cooling. However, studies relating to cooling transformations show that the cooling rate determines the structure of a steel of given composition. Certain phases, in particular bainite, or mixture of phases, bainite and perlite with very fine grains, characterized by good mechanical properties of toughness and ductility, can be sought in the case of suitable grades of steel.

Ainsi, dans la mesure où il serait possible de maîtriser avec précision la vitesse de refroidissement des plaques de tôles, le refroidissement accéléré à vitesse choisie pourrait se substituer pour des compositions bien définies du métal, au traitement de trempe et permettrait de produire directement les structures de métal recherchées sans pratiquer d'opération de revenu supplémentaire.Thus, insofar as it would be possible to precisely control the cooling rate of the sheet plates, accelerated cooling at a chosen speed could replace, for well defined metal compositions, the quenching treatment and would allow the structures to be produced directly. of metal sought without practicing an additional income transaction.

L'invention a donc pour but de fournir un procédé et une machine de refroidissement du type précité, permettant de régler et maîtriser la vitesse de refroidissement des plaques de tôle suivant des valeurs déterminées en fonction des structures souhaitées.The object of the invention is therefore to provide a method and a cooling machine of the aforementioned type, making it possible to adjust and control the cooling rate of the sheet metal plates according to values determined as a function of the desired structures.

A cet effet, l'invention a pour objet un procédé pour contrôler le refroidissement d'une tôle en vue de lui conférer une structure cristalline prédéterminée, suivant lequel on fait passer la tôle à refroidir à travers une enceinte contenant une masse de fluide de refroidissement régulièrement renouvelée, dont on règle le débit et dont on mesure la température, caractérisé en ce que, en fonction de l'épaisseur de la tôle et de la vitesse de refroidissement désirée, on détermine un flux thermique théorique devant être échangé entre la tôle et le fluide de refroidissement ; on calcule une vitesse d'écoulement théorique du fluide sur la tôle en fonction de la température d'arrivée du fluide de refroidissement et du flux thermique théorique ; on règle le débit du fluide de refroidissement en fonction de la vitesse théorique calculée ; on détermine une température théorique du fluide de refroidissement, en fonction du flux thermique ; on compare cette température théorique à la température mesurée, et l'on effectue une régulation de la température d'arrivée du fluide de refroidissement en fonction de cette température théorique.To this end, the subject of the invention is a method for controlling the cooling of a sheet in order to give it a predetermined crystal structure, according to which the sheet to be cooled is passed through an enclosure containing a mass of cooling fluid. regularly renewed, the flow rate of which is adjusted and the temperature of which is measured, characterized in that, as a function of the thickness of the sheet and the desired cooling rate, a theoretical heat flux is determined which must be exchanged between the sheet and the coolant; a theoretical flow speed of the fluid on the sheet is calculated as a function of the temperature of arrival of the cooling fluid and of the theoretical heat flow; the flow rate of the cooling fluid is adjusted as a function of the calculated theoretical speed; a theoretical temperature of the cooling fluid is determined, as a function of the heat flux; this theoretical temperature is compared with the measured temperature, and the inlet temperature of the cooling fluid is regulated as a function of this theoretical temperature.

L'invention a aussi pour objet une installation pour la mise en oeuvre du procédé défini ci-dessus, ladite installation comprenant une machine composée d'une enceinte comportant des moyens pour faire circuler un fluide de refroidissement qui se déplace à peu près parallèlement à la tôle, un bac de refroidissement, des moyens pour injecter le fluide de refroidissement contenu dans le bac à l'intérieur de ladite enceinte et des moyens pour évacuer le fluide de refroidissement après son parcours dans l'enceinte de refroidissement, un dispositif de commande du débit du fluide de refroidissement et un dispositif de mesure de la température du fluide de refroidissement, caractérisée en ce qu'elle comprend un organe de calcul du flux thermique théorique et un organe de calcul de la vitesse théorique, relié à l'organe de calcul du flux thermique théorique et au dispositif de mesure de la température, un dispositif de régulation de la température du fluide de refroidissement introduit dans l'enceinte, comportant deux entrées reliées respectivement au dispositif de mesure de la température du fluide de refroidissement et à un dispositif fournissant une valeur théorique de la température du fluide de refroidissement, et une sortie reliée à au moins une électro-vanne insérée dans un circuit d'alimentation en eau froide dudit bac de refroidissement.The invention also relates to an installation for implementing the method defined above, said installation comprising a machine composed of an enclosure comprising means for circulating a cooling fluid which moves roughly parallel to the sheet metal, a cooling tank, means for injecting the cooling fluid contained in the tank inside said enclosure and means for discharging the cooling fluid after it has passed through the cooling enclosure, a device for controlling the cooling fluid flow rate and a device for measuring the temperature of the cooling fluid, characterized in that it comprises a member for calculating the theoretical heat flux and a member for calculating the theoretical speed, connected to the calculating member of the theoretical heat flow and to the temperature measurement device, a device for regulating the temperature of the coolant introduced into the girdle, comprising two inputs connected respectively to the device for measuring the temperature of the coolant and to a device providing a theoretical value of the temperature of the coolant, and an output connected to at least one solenoid valve inserted in a circuit d cold water supply to said cooling tank.

Suivant une autre caractéristique, l'invention comprend des moyens de régulation de la pression du fluide à l'intérieur de l'enceinte.According to another characteristic, the invention comprises means for regulating the pressure of the fluid inside the enclosure.

D'autres caractéristiques et avantages de l'invention apparaîtront au cours de la description qui va suivre faite en regard des dessins annexés, donnés uniquement à titre d'exemple et dans lesquels :

  • la Figure 1 représente l'installation pour effectuer le refroidissement contrôlé des tôles ; et
  • la Figure 2 représente un mode de réalisation des moyens de commande et de régulation suivant l'invention.
Other characteristics and advantages of the invention will become apparent during the description which follows, given with reference to the appended drawings, given solely by way of example and in which:
  • Figure 1 shows the installation for carrying out the controlled cooling of the sheets; and
  • Figure 2 shows an embodiment of the control and regulation means according to the invention.

L'installation représentée à la Fig. comprend une machine de refroidissement 1, un bac de refroidissement 2, ainsi qu'un dispositif de commande et de régulation 3.The installation shown in FIG. includes a cooling machine 1, a cooling tank 2, and a control and regulation device 3.

La machine de refroidissement 1 est du type général décrit dans la demande de brevet n° 2 223 096. Cette machine est constituée d'une série de rouleaux de support et de guidage 4a, 4b jusqu'à 8a, 8b. D'une façon générale les éléments essentiels de la machine, disposés symétriquement de part et d'autre du plan moyen de la tôle seront désignés par les mêmes références numériques affectées d'indice a pour les éléments supérieurs et b pour les éléments inférieurs.The cooling machine 1 is of the general type described in patent application n ° 2 223 096. This machine consists of a series of support and guide rollers 4a, 4b to 8a, 8b. In general, the essential elements of the machine, arranged symmetrically on either side of the mean plane of the sheet will be designated by the same reference numerals assigned with index a for the upper elements and b for the lower elements.

La machine comprend une enveloppe ou enceinte métallique 9 qui s'étend entre les rouleaux de guidage en 10a, 10b, et entoure ces rouleaux en 11a, 11b. Les parois planes 10a, 10b sont à peu près parallèles et sont séparées par un intervalle supérieur à l'épaisseur de la tôle, de façon à délimiter avec cette dernière deux chambres ou canaux 12a, 12b d'épaisseur c. Des moyens de circulation d'eau comprennent au moins un conduit d'alimentation 13a, 13b, 14a, 14b s'étendant par exemple sur toute la longueur des rouleaux 5a, 5b, 7a, 7b et au moins un conduit d'évacuation 15a, 15b, 16a, 16b, 17a, 17b s'étendant également sur toute la longueur des rouleaux 4a, 4b, 68, 6b et 8a, 8b.The machine comprises a casing or metal container 9 which extends between the guide rollers 10a, 10b, and surrounds these rolls 11a, 11b. The flat walls 10a, 10b are substantially parallel and are separated by an interval greater than the thickness of the sheet, so as to delimit with the latter two chambers or channels 12a, 12b with a thickness c. Water circulation means comprise at least one supply conduit 13a, 13b, 14a, 14b extending for example over the entire length of the rollers 5 a, 5 b, 7 a, 7 b and at least one exhaust duct 15 a , 15 b , 16 a , 16 b , 17 a , 17 b also extending over the entire length of the rollers 4 a , 4 b , 6 8 , 6 b and 8 a , 8 b .

Le bac de refroidissement 2 contient l'eau de refroidissement ; sur ses flancs sont ménagés des orifices 18, 19 pour permettre la sortie de l'eau de refroidissement à destination de la machine 1 et des orifices d'entrée d'eau 20, 21 pour récupérer l'eau qui revient de la machine de refroidissement.The cooling tank 2 contains the cooling water; on its flanks are provided orifices 18, 19 to allow the exit of the cooling water intended for the machine 1 and water inlet orifices 20, 21 to recover the water which returns from the cooling machine .

Il comporte également sur sa partie supérieure un orifice de trop plein 22.It also has on its upper part an overflow orifice 22.

Les orifices 18 et 19 de sortie d'eau du bac 2 sont reliés aux conduits d'alimentation 13a, 13b, 14a, 14b de la machine par des conduits 23a, 23b par l'intermédiaire de pompes d'alimentation 24a, 24b. Les orifices d'entrée d'eau 20, 21 du bac 2 sont reliés aux conduits d'évacuation 15a, 15b, 16a, 16b, 17a, 17b par des conduits 25a, 25b au travers d'électro-vannes 26a, 26b. Une électro-vanne 27 montée sur la conduite 28 assure l'alimentation en eau froide du bac.The orifices 18 and 19 of water outlet of the tray 2 are connected to the supply conduits 13a, 13b, 14a, 14b of the machine through conduits 23a, 23b through feed pumps 24a, B. The water inlet orifices 20, 21 of tank 2 are connected to the discharge conduits 15 a , 15 b , 16 a , 16 b , 17 a , 17 b by conduits 25a, 25 b through electro -Vannes 26a, 26 b. A solenoid valve 27 mounted on line 28 ensures the supply of cold water to the tank.

Le dispositif de commande et de régulation 3 est constitué essentiellement par un calculateur qui peut être de type numérique, analogique ou hybride, ce dernier type étant adapté pour effectuer des traitements à la fois sur des grandeurs numériques et analogiques.The command and control device 3 essentially consists of a computer which can be of the digital, analog or hybrid type, the latter type being suitable for carrying out processing on both digital and analog quantities.

Le dispositif de commande et de régulation 3 représenté est de type hybride, il assure la commande et la régulation du débit des pompes 24a, 24b et des électro-vannes 26a, 26b et 27. Il est relié par ses entrées 11, 12 à un tableau d'affichage 29 des valeurs de consigne R relative à la vitesse de refroidissement recherchée et e relative à l'épaisseur de la tôle entrant dans la machine de refroidissement. Les valeurs de consigne R et e sont transmises selon une forme codée binaire aux entrées I1 et I2 du dispositif 3. L'entrée 13 est reliée à un capteur 30 de la pression atmosphérique P°. Les sorties 14 et 15 transmettent les ordres de commande aux pompes 24a et 24b. L'entrée 16 reçoit, d'une sonde thermométrique 32 disposée à l'intérieur du bac 2, la valeur de la température du liquide de refroidissement. Cette valeur de température est reçue sous la forme d'un signal analogique et sous la forme d'un mot binaire de plusieurs bits. Les sorties I7 à I9 assurent les commandes respectives des électro-vannes 27, 26b et 26a. Enfin, l'entrée I10 reçoit la valeur de la pression P relative de l'eau à l'entrée de l'enceinte 9 de la machine et transmise par un capteur de pression 33.The control and regulating device 3 shown is of hybrid type, it assures the control and regulation of the flow pumps 24a, 24b and solenoid valves 26a, 26b and 27. It is connected by its inputs 1 1 1 2 to a display table 29 of the set values R relating to the desired cooling speed and e relating to the thickness of the sheet metal entering the cooling machine. The setpoints R and e are transmitted in binary coded form to the inputs I 1 and I 2 of the device 3. The input 1 3 is connected to a sensor 30 of the atmospheric pressure P °. Outputs 1 4 and 1 5 transmit the control commands 24a and pump 24b. The inlet 1 6 receives, from a thermometric probe 32 disposed inside the tank 2, the value of the temperature of the coolant. This temperature value is received in the form of an analog signal and in the form of a binary word of several bits. The outputs I 7 to I 9 provide the respective controls for the solenoid valves 27, 26 b and 26a. Finally, the input I 10 receives the value of the relative pressure P of the water at the input of enclosure 9 of the machine and transmitted by a pressure sensor 33.

Les détails de réalisation du dispositif 3 de commande et de régulation sont représentés à la Fig. 2. Ce dispositif comprend un organe 34 de calcul de la valeur du flux thermique Ø échangé entre la tôle T et l'eau de refroidissement, un organe 35 de calcul de la vitesse du fluide de refroidissement nécessaire pour refroidir la tôle dans les conditions souhaitées, un organe 36 de commande du débit des pompes 24a et 24b, un organe 37 de régulation de la température de l'eau dans le bac 2 et un organe 38 de régulation de la pression à l'intérieur de l'enceinte 9 de refroidissement.The construction details of the control and regulation device 3 are shown in FIG. 2. This device comprises a member 34 for calculating the value of the heat flux Ø exchanged between the sheet metal T and the cooling water, a member 35 for calculating the speed of the cooling fluid necessary to cool the sheet metal under the desired conditions , a member 36 for controlling the flow rate of the pumps 24 a and 24 b , a member 37 for regulating the temperature of the water in the tank 2 and a member 38 for regulating the pressure inside the enclosure 9 cooling.

L'organe 34 est constitué par une mémoire morte programmable qui contient une table A1 donnant les valeurs du flux thermique Ø correspondant à différentes valeurs de consigne R et e. Cette table A1 peut être déterminée à partir d'un calcul théorique prenant en considération l'épaisseur c de la lame d'eau de refroidissement circulant au-dessus et en dessous de la tôle à refroidir, et les conditions thermiques aux limites, notamment le flux de chaleur échangé à la surface de la tôle. Ces calculs faisant intervenir les équations de la chaleur, aboutissent à des formules compliquées et il est préférable de construire la table A1 directement à partir d'essais pratiqués sur plusieurs épaisseurs de tôle et pour des vitesses de refroidissement différentes.The member 34 is constituted by a programmable read only memory which contains a table A 1 giving the values of the heat flux Ø corresponding to different set values R and e. This table A 1 can be determined from a theoretical calculation taking into account the thickness c of the cooling water sheet circulating above and below the sheet to be cooled, and the boundary thermal conditions, in particular the heat flow exchanged on the surface of the sheet. These calculations involving the heat equations, lead to complicated formulas and it is preferable to build the table A 1 directly from tests carried out on several sheet thicknesses and for different cooling rates.

L'organe 35 est également constitué par une mémoire morte programmable qui contient une table A2 donnant les valeurs de la vitesse de refroidissement correspondant aux différentes valeurs de flux thermique mémorisées dans la mémoire de l'organe 34 et à différentes valeurs de température 0 de l'eau de refroidissement. Cette table A2 est déterminée à partir de la relation qui lie le flux thermique 0 échangé, à la vitesse d'écoulement de l'eau de refroidissement et qui est donnée par la formule :

Figure imgb0001
où α(θ) est un coefficient qui ne dépend que de la température de l'eau de refroidissement.The member 35 is also constituted by a programmable read only memory which contains a table A 2 giving the values of the cooling rate corresponding to the different values of thermal flux stored in the memory of the member 34 and to different temperature values 0 of cooling water. This table A 2 is determined from the relation which links the heat flow 0 exchanged, to the flow speed of the cooling water and which is given by the formula:
Figure imgb0001
 where α (θ) is a coefficient which only depends on the temperature of the cooling water.

Cette formule a été obtenue à partir d'essais qui ont permis d'établir une relation entre des nombres caractéristiques de l'échange thermique et de l'écoulement.This formula was obtained from tests which made it possible to establish a relationship between numbers characteristic of heat exchange and flow.

L'organe 36 est également constitué par une mémoire morte programmable qui contient en mémoire une table A3 donnant les valeurs du débit des pompes en fonction des valeurs de la vitesse de l'eau de refroidissement lue dans la mémoire de l'organe 35.The member 36 is also constituted by a programmable read-only memory which contains in memory a table A 3 giving the values of the flow rate of the pumps as a function of the values of the speed of the cooling water read in the memory of the member 35.

Cette table peut facilement être construite à partir des caractéristiques techniques des pompes. L'organe 35 contient également un convertisseur numérique-analogique, non représenté, relié à la sortie de sa mémoire, nécessaire pour délivrer les signaux analogiques de commande des pompes 24a et 24b.This table can easily be constructed from the technical characteristics of the pumps. The unit 35 also contains a digital-analog converter, not shown, connected to the output of its memory, necessary for delivering the analog signals for controlling the pumps 24a and 24b.

La mémoire de l'organe 34 est connectée par ses deux entrées d'adressage aux entrées Il et 12 du dispositif 3 et par sa sortie, d'une part, à une entrée d'adressage de la mémoire de l'organe 35 et, d'autre part, à l'entrée d'un circuit 39 de multiplication situé dans l'organe de régulation 37. La mémoire de l'organe 35 est reliée sur sa deuxième entrée d'adressage à l'entrée 16 du dispositif 3 recevant le mot binaire transmis par la sonde thermométrique 32.The memory member 34 is connected by its two addressing inputs to it inputs and 1 2 of the device 3 and by its output, on the one hand, to a memory addressing input of the member 35 and , on the other hand, at the input of a multiplication circuit 39 located in the regulating member 37. The memory of the member 35 is connected on its second addressing input to the input 1 6 of the device 3 receiving the binary word transmitted by the temperature probe 32.

La sortie de l'organe 35 est reliée à l'entrée d'adressage de la mémoire de l'organe 36 et la sortie de l'organe 36 est connectée aux sorties 14 et 15 du calculateur 3.The output of the member 35 is connected to the addressing input of the memory of the member 36 and the output of the member 36 is connected to the outputs 1 4 and 1 5 of the computer 3.

L'organe de régulation 37 est constitué par le circuit de multiplication par une constante q, des potentiomètres 40, 41 et 42 utilisés respectivement pour l'affichage d'une constante p et des fourchettes + Δθ et - Δθ de régulation de la température de l'eau contenue dans le bac 2. Il est constitué également de circuits de sommation 43 et 44, d'un circuit de soustraction 45, de comparateurs 46 et 47 et d'un organe 50 de commande de l'électro-vanne d'apport d'eau 27. Les constantes p et q sont définies à partir des caractéristiques de l'installation par les formules suivantes :

Figure imgb0002
et
Figure imgb0003
où

  • 00 représente la température minimum de l'eau industrielle utilisée en tant que fluide de refroidissement.
  • 6c est la valeur critique de la température de l'eau de refroidissement correspondant à la tension de vapeur p = po - u1.
  • po étant la pression atmosphérique et u1 la hauteur des siphons formés par les conduits supérieurs d'évacuation (15a, 16a, 17a) de la machine.
The regulating member 37 is constituted by the multiplication circuit by a constant q, potentiometers 40, 41 and 42 used respectively for the display of a constant p and the ranges + Δθ and - Δθ for regulating the temperature of the water contained in the tank 2. It also consists of summing circuits 43 and 44, a subtraction circuit 45, comparators 46 and 47 and a member 50 for controlling the solenoid valve of water supply 27. The constants p and q are defined from the characteristics of the installation by the following formulas:
Figure imgb0002
 and
Figure imgb0003
 or
  • 0 0 represents the minimum temperature of industrial water used as a cooling fluid.
  • 6 c is the critical value of the cooling water temperature corresponding to the vapor pressure p = p o - u 1 .
  • p o being the atmospheric pressure and u 1 the height of the siphons formed by the upper discharge conduits (15a, 16a, 17a) of the machine.

Pendant l'opération de refroidissement la température de l'eau de refroidissement doit naturellement être comprise entre ces deux valeurs. During the cooling operation, the temperature of the cooling water must naturally be between these two values.

0M et 0m sont déterminés à partir de la formule (I) pour les valeurs respectives de θ0 et θc et pour des valeurs V de vitesse de la lame d'eau correspondantes, sachant que la vitesse V de la lame doit être supérieure à une vitesse critique Vc pour que le fluide de refroidissement remplisse l'enceinte. Cette vitesse critique correspond à une pression dynamique, exprimée en hauteur d'eau, égale à l'épaisseur du tunnel.0 M and 0 m are determined from formula (I) for the respective values of θ 0 and θ c and for values V of the speed of the water blade, knowing that the speed V of the blade must be higher than a critical speed V c for the coolant to fill the enclosure. This critical speed corresponds to a dynamic pressure, expressed in water height, equal to the thickness of the tunnel.

Le circuit 39 de multiplication par une constante est constitué de façon connue par un convertisseur numérique/analogique composé d'un réseau de cellules de résistances (R, 2R) en π dont on fait varier la tension d'alimentation en fonction de la valeur de la constante q.The circuit 39 for multiplication by a constant is constituted in a known manner by a digital / analog converter composed of a network of resistance cells (R, 2R) in π whose supply voltage is varied as a function of the value of the constant q.

Le circuit de sommation 43 est connecté par une entrée à la sortie du circuit 39 et par son autre entrée au curseur du potentiomètre 40.The summing circuit 43 is connected by an input to the output of the circuit 39 and by its other input to the cursor of the potentiometer 40.

Le circuit de sommation 44 est connecté par une entrée à la sortie du circuit 43 et par son autre entrée au curseur du potentiomètre 41. Le circuit de soustraction 45 est connecté par une entrée à la sortie du circuit 43 et par son autre entrée au curseur du potentiomètre 42.The summing circuit 44 is connected by an input to the output of the circuit 43 and by its other input to the cursor of the potentiometer 41. The subtraction circuit 45 is connected by an input to the output of the circuit 43 and by its other input to the cursor of potentiometer 42.

Le comparateur 46 a deux entrées, l'une est reliée à la borne d'entrée 16 du dispositif 3 pour recevoir le signal analogique transmis par la sonde thermométrique 32 et l'autre est reliée à la sortie du circuit 44. Le comparateur 47 a également deux entrées, l'une est reliée à la borne d'entrée 16 du dispositif 30 pour recevoir le signal analogique transmis par la sonde thermométrique 32, l'autre est reliée à la sortie du circuit 45. Les sorties des comparateurs 46 et 47 sont reliées à deux entrées respectives de l'organe 50.The comparator 46 has two inputs, one is connected to the input terminal 1 6 of the device 3 to receive the analog signal transmitted by the temperature probe 32 and the other is connected to the output of the circuit 44. The comparator 47 also has two inputs, one is connected to the input terminal 1 6 of the device 30 to receive the analog signal transmitted by the temperature probe 32, the other is connected to the output of the circuit 45. The outputs of the comparators 46 and 47 are connected to two respective inputs of the member 50.

L'organe de régulation 38 est constitué du potentiomètre 51, du circuit de sommation 52 et du comparateur 53. Le circuit 52 a deux entrées dont l'une est connectée à la borne 13 de l'organe 3 et l'autre est connectée au curseur de potentiomètre 51.The regulating member 38 consists of the potentiometer 51, the summing circuit 52 and the comparator 53. The circuit 52 has two inputs, one of which is connected to the terminal 1 3 of the member 3 and the other is connected to potentiometer cursor 51.

Le comparateur 53 a également deux entrées, l'une est reliée à la sortie du circuit 52 et l'autre est reliée à la borne d'entrée I10 du dispositif 3. La sortie du comparateur 53 est connectée aux bornes de sortie 18 et I9 du dispositif 3.Comparator 53 also has two inputs, one is connected to the output of circuit 52 and the other is connected to the input terminal I 10 of the device 3. The output of the comparator 53 is connected to the output terminals 1 8 and I 9 of the device 3.

Sur la Fig. 2 figurent également les dispositifs d'affichage des valeurs de consigne R et e du tableau d'affichage 29. Ces dispositifs sont constitués par des codeurs analogiques numériques 54 et 55 dont les sorties parallèles sont connectées respectivement aux bornes d'entrée I1 et I2 du dispositif 3. Ces codeurs peuvent être constitués par de simples registres d'interrupteurs dont l'état représente par exemple la valeur décimale codée en binaire de la valeur de consigne. On a également fait figurer sur la Fig. 2 le capteur de pression atmosphérique 30 relié à la borne 13 du dispositif 3 et le capteur de pression 33 relié à la borne I10.In Fig. 2 also show the devices for displaying the reference values R and e of the display panel 29. These devices are constituted by analog digital encoders 54 and 55 whose parallel outputs are connected respectively to the input terminals I 1 and I 2 of the device 3. These coders can consist of simple switch registers whose state represents for example the binary-coded decimal value of the set value. Also shown in FIG. 2 the atmospheric pressure sensor 30 connected to terminal 1 3 of the device 3 and the pressure sensor 33 connected to terminal I 10 .

Le fonctionnement de l'installation de refroidissement est le suivant. L'opérateur dispose des données de fabrication qui sont l'épaisseur e de la tôle et la vitesse de refroidissement R correspondant aux structures recherchées du métal. Ces deux données sont affichées sur les registres d'interrupteurs 55 et 54 du panneau d'affichage 29. Elles sont introduites sur les bornes d'entrée I1 et I2 du dispositif de commande et de régulation 3 en direction des entrées d'adressage de la mémoire de l'organe 34. Ces grandeurs d'entrée e et R adressent le contenu d'une zone de la mémoire de l'organe de calcul 34 dans laquelle se trouve la grandeur 0 correspondante du flux thermique théorique échangé entre la plaque de tôle et l'eau de refroidissement, suivant la relation 0 = A1 (R, e).The operation of the cooling installation is as follows. The operator has the manufacturing data which are the thickness e of the sheet and the cooling rate R corresponding to the desired structures of the metal. These two data are displayed on the switch registers 55 and 54 of the display panel 29. They are introduced on the input terminals I 1 and I 2 of the command and regulation device 3 in the direction of the addressing inputs. of the memory of the member 34. These input quantities e and R address the content of an area of the memory of the calculation member 34 in which the corresponding quantity 0 of the theoretical heat flux exchanged between the plate is located. of sheet metal and cooling water, according to the relation 0 = A 1 (R, e).

L'organe de calcul 35 détermine la vitesse V = A2 (0, 0) de la lame d'eau circulant sur la plaque de tôle, en fonction du flux thermique calculé précédemment par l'organe 34, et de la température régnant dans le bac 2. Ce calcul est effectué par adressage de la mémoire de l'organe 34 par les valeurs binaires de 0 et 0 transmises respectivement par l'organe 34 et la sonde thermométrique 32.The calculating member 35 determines the speed V = A 2 (0, 0) of the sheet of water circulating on the sheet metal plate, as a function of the heat flux previously calculated by the member 34, and of the temperature prevailing in tray 2. This calculation is carried out by addressing the memory of the member 34 with the binary values of 0 and 0 transmitted respectively by the member 34 and the thermometric probe 32.

Lorsque la vitesse V de l'écoulement de l'eau dans les canaux 12a, 12b est obtenue de l'organe 35, l'organe 36 de commande agit sur le débit des pompes 24a et 24b, de façon à ajuster le débit de l'eau de refroidissement dans les conduits 13a, 13b, 14a et 14b. Il résulte de ce qui précède que le dispositif de commande et de régulation 3 commande le débit des pompes pour réaliser la vitesse de refroidissement désirée en fonction des données de consigne : e = épaisseur de la tôle, R = vitesse de refroidissement et 0 = température de l'eau contenue dans le bac 2.When the velocity V of the water flow in the channels 12a, 12b is obtained from the member 35, the member 36 acts on the control speed of the pumps 24a and 24b, so as to adjust the flow rate cooling water in the conduits 13a, 13b, 14a and 14b. It follows from the above that the control and regulation device 3 controls the flow rate of the pumps to achieve the desired cooling speed as a function of the setpoint data: e = sheet thickness, R = cooling speed and 0 = temperature of water contained in tank 2.

Le dispositif de régulation 37 assure la régulation de la température de l'eau dans le bac 2. La température de fonctionnement relative à l'eau de refroidissement est déterminée par le circuit de sommation 43 et le circuit de multiplication par une constante 39. Le circuit 39 délivre une grandeur de sortie q · Ø qui est proportionnelle à la grandeur Ø du flux thermique échangé entre la plaque de tôle et l'eau de refroidissement. Cette grandeur q - 0 est additionnée à la constante p précitée affichée à l'intérieur de l'organe de calcul 37 sur le potentiomètre 40. La sortie du sommateur 43 délivre donc un signal d'amplitude Of = q - 0 + p. Les limites permises de variation de la température 0f sont affichées sur les potentiomètres 41 et 42, le potentiomètre 41 délivrant une valeur + Δθ et le potentiomètre 42 délivrant une valeur - Δθ. La valeur + Δθ est additionnée à la température de fonctionnement θf dans le circuit de sommation 44 qui délivre en sorti une valeur θf + Δθ. Cette valeur θf + Δθ théorique est comparée à la température de l'eau mesurée dans le bac 2, par le comparateur 46 dont la sortie commande l'organe de commande 50 de l'électro-vanne d'apport d'eau 27 lorsque la température 0 de l'eau mesurée est supérieure à la valeur calculée Δf + Δθ. D'une façon similaire le circuit de soustraction 45 soustrait de la valeur θ calculée, la valeur - Δθ transmise par le potentiomètre 42. Le résultat 0f - Δθ obtenu est comparé à la valeur θ de l'eau mesurée dans le bac 2 à l'aide du comparateur 47 pour fermer l'électro-vanne 27 lorsque la température de l'eau mesurée est inférieure à la valeur θf - Δθ calculée. Le circuit de régulation 38 permet d'agir à l'encontre des pertes de pression ayant lieu dans le circuit de retour et qui sont dues à la réduction du débit d'injection de l'eau réfrigérante par les pompes. Le circuit de sommation 52 additionne la valeur de la pression atmosphérique Po captée par le capteur de pression 30 à une valeur e affichée sur le potentiomètre 51 et transmet le résultat de la sommation Po + ε à l'entrée du comparateur 53 qui compare cette valeur à la valeur de pression P mesurée par le capteur de pression 33 à l'intérieur de l'enceinte de refroidissement 9. Lorsque la pression P apparaît pour le comparateur 53 supérieure à la pression Po + e celui-ci commande l'ouverture des électro-vannes de retour 26a, 26b. Par contre, si la pression P est égale ou inférieure à la pression Po + ε le comparateur 53 commande la fermeture des électro-vannes de retour 26a et 26b, de manière à augmenter la pression P à l'intérieur de l'enceinte de refroidissement.The regulating device 37 regulates the temperature of the water in the tank 2. The operating temperature relative to the cooling water is determined by the summing circuit 43 and the multiplication circuit by a constant 39. The circuit 39 delivers an output quantity q · Ø which is proportional to the quantity Ø of the heat flux exchanged between the sheet metal plate and the cooling water. This quantity q - 0 is added to the aforementioned constant p displayed inside the calculating member 37 on the potentiometer 40. The output of the summator 43 therefore delivers an amplitude signal Of = q - 0 + p. The permitted limits for variation of the temperature 0f are displayed on the potentiometers 41 and 42, the potentiometer 41 delivering a value + Δθ and the potentiometer 42 delivering a value - Δθ. The value + Δθ is added to the operating temperature θf in the summing circuit 44 which outputs a value θf + Δθ. This theoretical value θf + Δθ is compared with the temperature of the water measured in the tank 2, by the comparator 46, the output of which controls the control member 50 of the water supply solenoid valve 27 when the 0 temperature of the measured water is higher than the calculated value Δf + Δθ. Similarly, the subtraction circuit 45 subtracts from the calculated value θ, the value - Δθ transmitted by the potentiometer 42. The result 0f - Δθ obtained is compared to the value θ of the water measured in the tank 2 to l using comparator 47 to close the solenoid valve 27 when the measured water temperature is lower than the calculated value θf - Δθ. The regulation circuit 38 makes it possible to act against the pressure losses which take place in the return circuit and which are due to the reduction in the rate of injection of the cooling water by the pumps. The summation circuit 52 adds the value of the atmospheric pressure Po sensed by the pressure sensor 30 to a value e displayed on the potentiometer 51 and transmits the result of the summation Po + ε to the input of the comparator 53 which compares this value at the pressure value P measured by the pressure sensor 33 inside the cooling enclosure 9. When the pressure P appears for the comparator 53 greater than the pressure Po + e, the latter controls the opening of the electro -return valves 26a, 26b . By cons if the pressure P is equal to or less than the pressure Po + ε the comparator 53 controls the closing of the solenoid valves 26a and back 26b, so as to increase the pressure P within the enclosure cooling.

L'ensemble des dispositifs de régulation de la température et de la pression qui viennent d'être décrits procurent les avantages suivants.The set of temperature and pressure control devices which have just been described provide the following advantages.

Tout d'abord le dispositif de régulation de la température maintient l'eau du bac à une température constante, ce qui permet premièrement, de maintenir à un niveau constant le flux de chaleur échangé entre la tôle et l'eau de refroidissement et deuxièmement, de garder à un niveau constant la tension de vapeur dans le siphon formé par les conduits d'évacuation 16a, 17a, évitant ainsi le désamorçage de ce dernier et l'écoulement de l'eau par les extrémités de la machine.First of all, the temperature regulation device keeps the water in the tank at a constant temperature, which allows firstly, to maintain at a constant level the heat flow exchanged between the sheet and the cooling water and secondly, to keep the vapor pressure in the siphon formed by the discharge conduits 16a, 17a at a constant level, thus avoiding the defusing of the latter and the flow of water through the ends of the machine.

En second lieu, la présence des électro-vannes 26a et 26b dans chacun des circuits d'évacuation, et dont l'ouverture est asservie au débit des pompes d'alimentation, permet d'éviter les effets dus aux pertes de pression dans la machine. Leur action dans le circuit de retour, en maintenant la pression à l'intérieur de l'enceinte légèrement supérieure à la pression atmosphérique, permet d'éviter les entrées d'air dans la machine qui nuiraient à son bon fonctionnement.Secondly, the presence of the electromagnetic valves 26a and 26b in each of the discharge circuits, and whose opening is controlled to the flow of the feeding pumps, avoids effects due to pressure losses in the machine. Their action in the return circuit, while maintaining the pressure inside the enclosure slightly higher than atmospheric pressure, makes it possible to avoid air entering the machine which would adversely affect its proper functioning.

L'exemple de réalisation de l'invention qui vient d'être décrit a été donné dans une version hybride analogique numérique de l'organe de commande et de régulation 3. Il est bien évident que l'on pourrait arriver au même résultat avec un calculateur numérique programmé. Dans ce cas il suffirait de mémoriser les données de consigne e et R ainsi que les tables Ai, A2 et A3 dans la mémoire du calculateur et de calculer les valeurs théoriques du flux thermique 0 et de la vitesse V d'écoulement par exécution de programmes correspondants.The embodiment of the invention which has just been described has been given in a hybrid analog digital version of the command and control member 3. It is quite obvious that the same result could be achieved with a programmed digital computer. In this case, it would suffice to store the setpoint data e and R as well as the tables A i , A 2 and A 3 in the memory of the computer and to calculate the theoretical values of the heat flow 0 and of the flow speed V by execution of corresponding programs.

On notera également que la plupart des opérations décrites ci-dessus pourraient également être réalisées manuellement, dans ce cas la commande des pompes pourrait être réalisée par la lecture d'abaques correspondants aux tables Ai, A2 et A3 précédemment décrites.It will also be noted that most of the operations described above could also be carried out manually, in this case the control of the pumps could be carried out by reading charts corresponding to the tables A i , A 2 and A 3 previously described.

Claims (7)

1. A process for controlling the cooling of a metal sheet for the purpose of imparting thereto a predetermined crystalline structure, wherein the sheet to be cooled is passed through a case containing a mass of cooling fluid which is regularly renewed, the flow of the cooling fluid being controlled and its temperature measured, characterized in that, according to the thickness of the sheet to be cooled and the desired cooling rate, a theoretical thermal flux is determined, which should be exchanged between the metal sheet and the cooling fluid ; a theoretical flow speed of the fluid on the metal sheet is calculated as a function of the inlet temperature of the cooling fluid and of the theoretical thermal flux ; the flow rate of the cooling fluid is controlled as a function of the calculated flow speed ; a theoretical temperature of the cooling fluid is determined as a function of the theoretical thermal flux ; said theoretical temperature to the measured temperature and the inlet temperature of the cooling fluid is regulated as a function of said theoretical temperature.
2. A process according to claim 1, characterized in that the pressure at the ends of the case is maintained at a value higher than the atmospheric pressure.
3. A plant for carrying out the process according to claim 1, comprising a machine (1) including a case comprising means (10a, 10b) for circulating a cooling fluid which moves in a direction substantially parallel to the metal sheet, a cooling tank (2), means (13a, 13b, 23a, 23b) for injecting the cooling fluid contained in the tank inside said case, and means (17a, 17b, 25a, 25b) for discharging the cooling fluid after it has travelled through the cooling case, a control device (24a, 24b) for controlling the flow of the cooling fluid and a device (32) for measuring the temperature of the cooling fluid, characterized in that it comprises means (34) for calculating the theoretical thermal flux and means (35) for calculating the theoretical speed, connected to the means (34) for calculating the theoretical thermal flux and to the device (32) for measuring the temperature, a device (37) for regulating the temperature of the cooling fluid introduced into the case, comprising two inputs connected respectively to the device (32) for measuring the temperature of the cooling liquid and to a device (39, 43) providing a theoretical value of the temperature of the cooling fluid, and an output connected to at least an electrically operated valve (27) inserted in a circuit (28) for feeding cool water into said cooling tank.
4. A plant according to claim 3, characterized in that the device (37) for regulating the temperature of the cooling fluid comprises means (39, 43) for calculating the desired cooling temperature as a function of the thermal flux calculated in the calculating means (34).
5. A plant according to claim 3, characterized in that the device (37) for regulating the temperature of the cooling fluid comprises :
- means (39, 43) for calculating the desired cooling temperature as a function of the thermal flux calculated in the calculating means (34) ;
- a probe (32) for measuring the temperature of the cooling fluid entering said case ;
- a comparator (46, 47) for comparing the cooling temperature calculated in the calculating means (37, 43) and the temperature measured by the measuring probe (32) ; and
- at least one electrically operated valve (27) inserted in the circuit (28) feeding cool water into said cooling tank, and connected to said comparator (46, 47).
6. A plant according to claim 3, characterized in that it comprises means (38) for regulating the pressure of the fluid at the ends of the case.
7. A plant according to claim 6, characterized in that the means (38) for regulating the pressure of the fluid inside the case comprise :
- a first sensor (33) for measuring the pressure at the ends of said case (9) ;
- a second sensor (30) for measuring the atmospheric pressure ;
- a comparator (53) connected to said sensors for comparing the pressure measured in the case with the atmospheric pressure measured by the second sensor ;
- at least an electrically operated valve (26a, 26b) inserted in said means for discharging the fluid and controlled by the result of the comparison effected by said comparator (53) in such manner that the electrically operated valves be closed when the pressure measured by the first sensor is lower than or equal to the atmospheric pressure.
EP19820402134 1981-11-26 1982-11-23 Method and device for the controlled cooling of sheets Expired EP0080932B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8122142 1981-11-26
FR8122142A FR2517039A1 (en) 1981-11-26 1981-11-26 METHOD AND INSTALLATION FOR PERFORMING COOLING CONTROL OF SHEETS

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EP0080932A1 EP0080932A1 (en) 1983-06-08
EP0080932B1 true EP0080932B1 (en) 1985-04-24

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EP19820402134 Expired EP0080932B1 (en) 1981-11-26 1982-11-23 Method and device for the controlled cooling of sheets

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EP (1) EP0080932B1 (en)
JP (1) JPS58126933A (en)
DE (1) DE3263303D1 (en)
FR (1) FR2517039A1 (en)
SU (1) SU1131461A3 (en)

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JP4678112B2 (en) * 2001-09-21 2011-04-27 Ｊｆｅスチール株式会社 Steel plate cooling method and apparatus
EP3645182B1 (en) * 2017-06-26 2021-08-04 Arcelormittal Method and electronic device for determining the temperature of a metal strip, related control method, computer program, control apparatus and hot rolling installation
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CZ305469B6 (en) * 2014-03-26 2015-10-14 Technická univerzita v Liberci, Katedra strojírenské technologie Method of determining cooling ability of a medium for particular processed materials including possibility to simulate heat treatment of dimensional parts

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JPH0471968B2 (en) 1992-11-17
SU1131461A3 (en) 1984-12-23
DE3263303D1 (en) 1985-05-30
FR2517039B1 (en) 1984-12-14
JPS58126933A (en) 1983-07-28
EP0080932A1 (en) 1983-06-08
FR2517039A1 (en) 1983-05-27

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