EP0036365A1 - Process for manufacturing workpieces by hydraulic-pressure shaping, and apparatus for carrying out this process - Google Patents

Process for manufacturing workpieces by hydraulic-pressure shaping, and apparatus for carrying out this process Download PDF

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Publication number
EP0036365A1
EP0036365A1 EP81400387A EP81400387A EP0036365A1 EP 0036365 A1 EP0036365 A1 EP 0036365A1 EP 81400387 A EP81400387 A EP 81400387A EP 81400387 A EP81400387 A EP 81400387A EP 0036365 A1 EP0036365 A1 EP 0036365A1
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EP
European Patent Office
Prior art keywords
blank
internal pressure
function
longitudinal compression
pressure
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Granted
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EP81400387A
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German (de)
French (fr)
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EP0036365B1 (en
Inventor
Richard Esperou
André Garnier
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Vallourec SA
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Vallourec SA
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Priority to AT81400387T priority Critical patent/ATE9283T1/en
Publication of EP0036365A1 publication Critical patent/EP0036365A1/en
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Publication of EP0036365B1 publication Critical patent/EP0036365B1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D26/00—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces
    • B21D26/02—Shaping without cutting otherwise than using rigid devices or tools or yieldable or resilient pads, i.e. applying fluid pressure or magnetic forces by applying fluid pressure
    • B21D26/033—Deforming tubular bodies
    • B21D26/041—Means for controlling fluid parameters, e.g. pressure or temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
    • B21C37/15—Making tubes of special shape; Making tube fittings
    • B21C37/28—Making tube fittings for connecting pipes, e.g. U-pieces
    • B21C37/29—Making branched pieces, e.g. T-pieces
    • B21C37/294—Forming collars by compressing a fluid or a yieldable or resilient mass in the tube

Definitions

  • the present invention relates to a method and a device for manufacturing by hydroflambing hollow metal parts from tubular blanks or the like.
  • the present invention aims more specifically to bring improvements to the technique of hydroflambing, or hydroforming, which consists in producing the part with the desired shape in a single operation, from a blank, in a matrix of corresponding shape in associating a mechanical action obtained by the pushing of one or more pistons and a hydraulic pressure using a liquid, in particular water filling the interior of the blank.
  • the tube sections have dimensional irregularities relating to their thickness or due to ovalizations or eccentricities which are inevitable with their current manufacturing processes. These irregularities are such that the already known hydrofoaming methods are not currently satisfactory.
  • the present invention aims to provide a method and a device making it possible to avoid the above-mentioned drawbacks of previously known methods and devices and to obtain hollow metal parts having in particular constant dimensional characteristics, at rates compatible with industrial exploitation. economical in minimizing manufacturing waste, and this from tubular blanks obtained in particular by cutting tubes.
  • the present invention relates to a new process for obtaining by hydroflambing shaped parts such as T or bulbs from a blank in the form of a section of tube or in a similar form, by applying a mechanical stress in the longitudinal direction of the blank and a hydraulic pressure inside it, so as to obtain a deformation of the blank in the transverse direction, a process characterized in that after having subjecting the blank to a given longitudinal compression, the pressure inside the blank is caused to obtain a transverse deformation of the latter, and which is determined as a function of the value of the pressure internal and / or transverse deformation of the blank, the law of variation which is subsequently subjected to the internal pressure of the blank as a function of the longitudinal compression to which it is subjected.
  • the method according to the invention therefore initially allows a kind of blank test to be carried out, for example by measuring the internal pressure which must be applied to it while subjecting it to a predetermined axial compression in order to obtain a deformation. cross-section of a preset value.
  • the internal pressure that has thus been measured has a value which depends on the mechanical characteristics of the blank which, as explained above, depend on the one hand on the dimensions and in particular on the thickness or the eccentricity of the tube section and on the other hand of its metallurgical qualities.
  • This hydroflamming curve is, according to the invention, defined by the instantaneous value of the internal pressure which must be applied to the blank for each value of the longitudinal deformation of the blank due to the mechanical forces that she suffers.
  • the present invention also relates to a device for implementing the method defined above, this device comprising a matrix capable of receiving a tubular blank or the like and a means making it possible to reign inside the blank.
  • adjustable pressure characterized in that it further comprises a means for measuring the transverse deformations of the blank, a means for measuring the longitudinal compression of the blank, and a means for varying the internal pressure of the blank according to its longitudinal compression according to a predetermined law chosen according to the value of the internal pressure and / or the transverse deformation of the blank.
  • the means for determining the longitudinal compression of the blank as well as the means for determining its transverse deformation can be constituted by rheostatic feelers which supply these quantities in electrical form.
  • the method according to the invention is in particular intended to produce single or multiple T's from sections of tube. It is also well suited for making parts having a bulb in their central part such as, for example, vehicle rear axles. However, the method according to the invention also makes it possible to produce parts having a different shape.
  • the time required for the hydroflambing process according to the invention can vary depending on the nature and the size of the parts, for example between ten and a few tens of seconds.
  • the characteristic process of the process according to the invention can be repeated at time intervals which are for example of the order of 2 to 4 seconds depending on the nature of the parts to be deformed.
  • the drawing shows a matrix, the lower part 1 of which is fixed and the upper part 2 of which is mounted on a movable piston 3.
  • the matrix has the general shape of a T, the blank formed by a section of tube to be placed from right to left between the pistons 4 and 5 of two hydraulic cylinders mounted in the chassis 6 of the device.
  • the piston 7 of a hydraulic cylinder engages in the lower branch of the T made in the matrix.
  • the piston 7 is initially pushed up against the tubular blank while remaining applied against the latter by a constant adjustable force. In this way, the piston 7 serves, so to speak, as a feeler to follow the transverse deformations of the blank during the hydroflambing process.
  • a hydraulic pump 8 controls the pistons 3 and 7 by means of the slide devices 9 and 10 which make it possible to raise and lower the mobile upper part 2 of the matrix and to allow it to move downwards by opposing a preset force.
  • the piston 7 which can also be pushed upwards at the end of the process to release the T which has just been manufactured after, of course, opening the upper part 2 of the matrix.
  • a hydraulic pump 11 supplies a pressure multiplier device with differential pistons 12, by means of an electrical control system 13, the high pressure fluid is sent by a pipe inside the blank and passing through the orifice 14 which is formed inside the piston 5.
  • a hydraulic pump 15 supplies fluid under pressure to the cylinders of the pistons 4 and 5 which provide axial compression of the blank.
  • a drawer 16 makes it possible to reverse the movement of these pistons 4 and 5.
  • a device which may for example be of the mechanical or hydraulic type, causes them to move the pistons 4 and 5 are necessarily symmetrical with respect to the matrix 1.
  • An electronic computer 17 is simultaneously connected to a rheostatic probe 18 which measures the displacements of the piston 7, to a rheostatic probe 19 which measures the displacements of the piston 4, to a pressure gauge 20 which measures the pressure inside the blank, to a pressure gauge 21 which measures the pressure acting on the pistons 4 and 5 and finally to the device 13 which determines the instantaneous value of the pressure inside the blank.
  • the operation of the device is as follows, starting from the position shown in the drawing, the device not containing a blank.
  • the piston 3 and the upper part 2 of the matrix are raised, which makes it possible to introduce a tubular blank, not shown inside the matrix, between the pistons 4 and 5, which include organs of sealing so that the necessary pressure can be applied inside the blank.
  • the movable part of the die is lowered to firmly maintain the section of tube during the hydroflambing process.
  • compression is applied longitudinally to the blank, the value of which is determined by the computer 17 as a function of the pressure measured by the pressure gauge 21.
  • the purpose of this longitudinal compression of the blank is to ensure sealing and subjecting the blank to longitudinal stress.
  • the piston 7 is brought upwards in contact with the blank through the drawer 10 which holds the piston 7 applied against the blank with constant force.
  • the electronic computer causes the progressive increase of the pressure inside the blank which results in a downward displacement of the piston 7 which is measured by the probe which transmits this information to the computer 17.
  • the computer 17 controls the device 13 which determines the pressure inside the blank so that, as a function of the displacement of the piston 4 measured by the feeler 19 la pressure prevailing inside the blank is determined according to a law previously stored in the computer 17 and which is chosen by the computer according to the value of the pressure inside the blank at moment when the piston 7 has undergone the displacement of predetermined value.
  • the hydrofoaming process then continues as a function of the law of variation of the internal pressure which has been determined by the computer 17 as a function of the criteria which have just been described. .
  • the computer 17 measures the pressure inside the blank at this instant and as a function of this pressure, once again chooses the law of variation of the internal pressure of the blank as a function of the displacement of the piston 4 according to the value of the internal pressure of the blank at the time when the second predetermined displacement of the piston 7 was reached.
  • the means for measuring the longitudinal and transverse deformations of the blank could be different from those which have been described.
  • the choice of the law of variation of the internal pressure as a function of the longitudinal compression could also be determined as a function of the transverse deformation obtained for a given internal pressure.

Abstract

1. A method for obtaining by the hydraulic bending process, pieces of such shapes as T, or bulb sections from blanks having the shape of a tubular cross section or a similar shape, wherein one applies mechanical compression in the longitudinal direction of the blank and then hydraulic pressure within the latter so as to obtain a deformation of the blank in the transverse direction, the method being characterized in that it comprises at least one stage consisting in measuring, when the longitudinal compression attains a predetermined value, the corresponding value, the corresponding value of the internal pressure and/or of the transverse deformation of the blank, and in determining, depending on the said corresponding value, the subsequent relationship between the internal pressure and the longitudinal compression.

Description

La présente invention est relative à un procédé et à un dispositif pour fabriquer par hydroflambage des pièces métalliques creuses à partir d'ébauches tubulaires ou analogues.The present invention relates to a method and a device for manufacturing by hydroflambing hollow metal parts from tubular blanks or the like.

Il existe actuellement différentes techniques de formage à froid pour fabriquer à partir d'ébauches des pièces métalliques creuses telles que par exemple des pièces à bulbe et en particulier des raccords en T destinés à former des dérivations dans des canalisations de transport de liquides ou de gaz. Parmi ces techniques, on peut notamment citer le formage électro-hydraulique, le formage électro-magnétique, le formage par explosion et l'hydroflambage.There are currently various cold forming techniques for manufacturing hollow metal parts from blanks, such as bulb parts for example, and in particular T-fittings intended to form branches in liquid or gas transport pipes. . Among these techniques, mention may in particular be made of electro-hydraulic forming, electro-magnetic forming, explosion forming and hydrofoaming.

La présente invention vise plus précisément à apporter des perfectionnements à la technique de l'hydroflambage, ou hydroformage, qui consiste à réaliser la pièce à la forme désirée en une seule opération, à partir d'une ébauche, dans une matrice de forme correspondante en associant une action mécanique obtenue par la poussée d'un ou plusieurs pistons et une pression hydraulique à l'aide d'un liquide, notamment de l'eau remplissant l'intérieur de l'ébauche.The present invention aims more specifically to bring improvements to the technique of hydroflambing, or hydroforming, which consists in producing the part with the desired shape in a single operation, from a blank, in a matrix of corresponding shape in associating a mechanical action obtained by the pushing of one or more pistons and a hydraulic pressure using a liquid, in particular water filling the interior of the blank.

Afin d'obtenir des pièces de qualité et de forme aussi constantes que possible on a déjà proposé divers procédés et dispositifs pour réguler pendant l'opération d'hydroflambage la pression ou le volume du liquide à l'intérieur de l'ébauche en fonction du déplacement du ou des pistons assurant l'action mécanique.In order to obtain parts of quality and shape that are as constant as possible, various methods and devices have already been proposed for regulating during the hydrofoaming operation the pressure or the volume of the liquid inside the blank depending on the displacement of the piston or pistons ensuring the mechanical action.

Un inconvénient commun aux procédés et aux dispositifs actuellement connus, tant ceux assurant une régulation de pression que ceux assurant une régulation de volume, est qu'ils ne permettent d'assurer des résultats industriels satisfaisants que si les ébauches de départ présentent toutes des caractéristiques dimensionnelles et métallurgiques parfaitement définies et constantes. Ces procédés et dispositifs antérieurs peuvent ainsi être éventuellement intéressants sur le plan économique pour des ébauches obtenues par emboutissage de tôle mais ne sont pas satisfaisants lorsque l'on cherche à utiliser des ébauches de départ constituées chacune par exemple par un tronçon de tube.A drawback common to currently known methods and devices, both those ensuring regulation of pressure that those ensuring a volume regulation, is that they allow to ensure satisfactory industrial results only if the starting blanks all have perfectly defined and constant dimensional and metallurgical characteristics. These prior methods and devices can thus possibly be advantageous from an economic point of view for blanks obtained by stamping sheet metal but are not satisfactory when it is sought to use starting blanks each consisting for example of a section of tube.

En effet, on constate que les tubes d'acier fabriqués industriellement, notamment les tubes en acier inoxydable fabriqués par extrusion à chaud, présentent des irrégularités de structure, avec des zones présentant une structure à grains fins et des zones présentant des gros grains. Ces irrégularités de structure entraînent des irrégularités de limites d'écoulement qui, au cours d'un processus d'hydroflambage, se traduisent d'une part par des variations de la déformation plastique de l'ébauche selon les zones de celles-ci, et d'autre part par des phénomènes d'instabilité qui peuvent entraîner la rupture de l'ébauche en cours de formage.In fact, it can be seen that industrially manufactured steel tubes, in particular stainless steel tubes produced by hot extrusion, have structural irregularities, with zones having a fine-grained structure and zones having large grains. These structural irregularities result in irregularities in flow limits which, during a hydrofoaming process, result on the one hand in variations in the plastic deformation of the blank according to the zones thereof, and on the other hand by instability phenomena which can lead to the rupture of the blank during forming.

Par ailleurs, les tronçons de tube présentent des irrégularités dimensionnelles relatives à leur épaisseur ou dues à des ovalisations ou des excentrations qui sont inévitables avec leurs procédés actuels de fabrication. Ces irrégularités sont telles que les procédés d'hydroflambage déjà connus ne donnent actuellement pas satisfaction.Furthermore, the tube sections have dimensional irregularities relating to their thickness or due to ovalizations or eccentricities which are inevitable with their current manufacturing processes. These irregularities are such that the already known hydrofoaming methods are not currently satisfactory.

La présente invention vise à fournir un procédé et un dispositif permettant d'éviter les inconvénients mentionnés ci-dessus des procédés et dispositifs antérieurement connus et d'obtenir des pièces métalliques creuses présentant notamment des caractéristiques dimensionnelles constantes, à des cadences compatibles avec une exploitation industrielle économique en réduisant au maximum les rebuts de fabrication, et ce à partir d'ébauches tubulaires obtenues notamment par tronçonnage de tubes.The present invention aims to provide a method and a device making it possible to avoid the above-mentioned drawbacks of previously known methods and devices and to obtain hollow metal parts having in particular constant dimensional characteristics, at rates compatible with industrial exploitation. economical in minimizing manufacturing waste, and this from tubular blanks obtained in particular by cutting tubes.

La présente invention a pour objet un nouveau procédé pour obtenir par hydroflambage des pièces de forme telles que des T ou des bulbes à partir d'ébauche se présentant sous la forme d'une section de tube ou sous une forme analogue, par application d'une contrainte mécanique dans le sens longitudinal de l'ébauche et d'une pression hydraulique à l'intérieur de celle-ci, de manière à obtenir une déformation de l'ébauche dans le sens transversal, procédé caractérisé par le fait qu'après avoir soumis l'ébauche à une compression longitudinale donnée, l'on provoque une augmentation de la pression à l'intérieur de l'ébauche pour obtenir une déformation transversale de cette dernière, et que l'on détermine en fonction de la valeur de la pression interne et/ou de la déformation transversale de l'ébauche, la loi de variation que l'on fait subir ultérieurement à la pression interne de l'ébauche en fonction de la compression longitudinale à laquelle on la soumet.The present invention relates to a new process for obtaining by hydroflambing shaped parts such as T or bulbs from a blank in the form of a section of tube or in a similar form, by applying a mechanical stress in the longitudinal direction of the blank and a hydraulic pressure inside it, so as to obtain a deformation of the blank in the transverse direction, a process characterized in that after having subjecting the blank to a given longitudinal compression, the pressure inside the blank is caused to obtain a transverse deformation of the latter, and which is determined as a function of the value of the pressure internal and / or transverse deformation of the blank, the law of variation which is subsequently subjected to the internal pressure of the blank as a function of the longitudinal compression to which it is subjected.

Le procédé conforme à l'invention permet donc dans un premier temps de procéder à une sorte de test de l'ébauche en mesurant par exemple la pression interne qu'il faut lui appliquer tout en la soumettant à une compression axiale prédéterminée pour obtenir une déformation transversale d'une valeur préétablie. La pression interne que l'on a ainsi mesurée a une valeur qui dépend des caractéristiques mécaniques de l'ébauche qui dépendent, comme cela a été expliqué précédemment, d'une part des dimensions et en particulier de l'épaisseur ou de l'excentration de la section de tube et d'autre part de ses qualités métallurgiques.The method according to the invention therefore initially allows a kind of blank test to be carried out, for example by measuring the internal pressure which must be applied to it while subjecting it to a predetermined axial compression in order to obtain a deformation. cross-section of a preset value. The internal pressure that has thus been measured has a value which depends on the mechanical characteristics of the blank which, as explained above, depend on the one hand on the dimensions and in particular on the thickness or the eccentricity of the tube section and on the other hand of its metallurgical qualities.

La valeur ainsi mesurée de la pression interne qui provoque une déformation transversale prédéterminée de l'ébauche permet de sélectionner la loi d'hydroflambage à laquelle on doit soumettre l'ébauche pour l'obtention d'un produit satisfaisant. Cette courbe d'hydroflambage.est, conformément à l'invention, définie par la valeur instantanée de la pression interne que l'on doit appliquer sur l'ébauche pour chaque valeur de la déformation longitudinale de l'ébauche due aux efforts mécaniques qu'elle subit.The value thus measured of the internal pressure which causes a predetermined transverse deformation of the blank allows to select the hydroflambing law to which the blank must be subjected to obtain a satisfactory product. This hydroflamming curve is, according to the invention, defined by the instantaneous value of the internal pressure which must be applied to the blank for each value of the longitudinal deformation of the blank due to the mechanical forces that she suffers.

Les différentes lois d'hydroflambage possibles sont déterminées préalablement de manière expérimentale, chacune d'elles correspondant par exemple à une ébauche de structure donnée.The various possible hydroflambing laws are determined beforehand in an experimental manner, each of them corresponding for example to a blank of given structure.

Conformément à l'invention, il est également possible de renouveler plusieurs fois le processus qui vient d'être décrit au cours de l'hydroformage d'une pièce donnée. Il suffit pour cela de déterminer par exemple la pression régnant à l'intérieur de l'ébauche à l'instant où la déformation transversale de cette dernière atteint une nouvelle valeur prédéterminée supérieure à la précédente, pour sélectionner la loi selon laquelle on poursuivra la déformation en maintenant à l'intérieur de l'ébauche une pression instantanée fonction de la compression longitudinale de l'ébauche.In accordance with the invention, it is also possible to repeat the process which has just been described several times during the hydroforming of a given part. It suffices for this to determine for example the pressure prevailing inside the blank at the moment when the transverse deformation of the latter reaches a new predetermined value greater than the previous one, to select the law according to which the deformation will be continued. maintaining an instantaneous pressure inside the blank as a function of the longitudinal compression of the blank.

La présente invention a également pour objet un dispositif pour la mise en oeuvre du procédé défini ci-dessus, ce dispositif comportant une matrice susceptible de recevoir une ébauche tubulaire ou analogue et un moyen permettant de faire régner à l'intérieur de l'ébauche une pression réglable, caractérisé par le fait qu'il comporte en outre un moyen pour mesurer les déformations transversales de l'ébauche, un moyen pour mesurer la compression longitudinale de l'ébauche, et un moyen permettant de faire varier la pression interne de l'ébauche en fonction de sa compression longitudinale selon une loi prédéterminée choisie en fonction de la valeur de la pression interne et/ou de la déformation transversale de l'ébauche.The present invention also relates to a device for implementing the method defined above, this device comprising a matrix capable of receiving a tubular blank or the like and a means making it possible to reign inside the blank. adjustable pressure, characterized in that it further comprises a means for measuring the transverse deformations of the blank, a means for measuring the longitudinal compression of the blank, and a means for varying the internal pressure of the blank according to its longitudinal compression according to a predetermined law chosen according to the value of the internal pressure and / or the transverse deformation of the blank.

Le moyen pour déterminer la compression longitudinale de l'ébauche ainsi que le moyen pour déterminer sa déformation transversale peuvent être constitués par des palpeurs rhéostatiques qui fournissent ces grandeurs sous forme électrique.The means for determining the longitudinal compression of the blank as well as the means for determining its transverse deformation can be constituted by rheostatic feelers which supply these quantities in electrical form.

Le procédé selon l'invention est en particulier destiné à réaliser des T simples ou multiples à partir de sections de tube. Il est également bien adapté pour réaliser des pièces présentant un bulbe dans leur partie centrale telles que par exemple des ponts arrières de véhicule. Cependant, le procédé selon l'invention permet également de réaliser des pièces ayant une forme différente.The method according to the invention is in particular intended to produce single or multiple T's from sections of tube. It is also well suited for making parts having a bulb in their central part such as, for example, vehicle rear axles. However, the method according to the invention also makes it possible to produce parts having a different shape.

Conformément à l'invention, on peut ainsi transformer par hydroflambage des pièces pesant par exemple de 0,5 à 10 kilos et ayant une épaisseur comprise entre par exemple 3 à 15 millimètres.According to the invention, it is thus possible to transform by hydroflambing pieces weighing for example from 0.5 to 10 kilos and having a thickness of between for example 3 to 15 millimeters.

Le temps nécessaire au processus hydroflambage selon l'invention peut varier selon la nature et la dimension des pièces entre par exemple une dizaine et quelques dizaines de secondes.The time required for the hydroflambing process according to the invention can vary depending on the nature and the size of the parts, for example between ten and a few tens of seconds.

Le processus caractéristique du procédé selon l'invention peut être renouvelé à des intervalles de temps qui sont par exemple de l'ordre de 2 à 4 secondes en fonction de la nature des pièces à déformer.The characteristic process of the process according to the invention can be repeated at time intervals which are for example of the order of 2 to 4 seconds depending on the nature of the parts to be deformed.

Dans le but de mieux faire comprendre l'invention on va en décrire maintenant à titre d'illustration et sans aucun caractère limitatif un mode de mise en oeuvre à l'aide d'un dispositif schématiquement représenté sur la figure unique du dessin annexé.In order to better understand the invention will now be described by way of illustration and without any limiting character an embodiment using a device schematically shown in the single figure of the accompanying drawing.

On a représenté sur le dessin une matrice dont la partie inférieure 1 est fixe et dont la partie supérieure 2 est montée sur un piston mobile 3. La matrice a la forme générale d'un T, l'ébauche constituée par un tronçon de tube devant être placée de droite à gauche entre les pistons 4 et 5 de deux vérins hydrauliques montés dans le châssis 6 du dispositif.The drawing shows a matrix, the lower part 1 of which is fixed and the upper part 2 of which is mounted on a movable piston 3. The matrix has the general shape of a T, the blank formed by a section of tube to be placed from right to left between the pistons 4 and 5 of two hydraulic cylinders mounted in the chassis 6 of the device.

Le piston 7 d'un vérin hydraulique s'engage dans la branche inférieure du T pratiqué dans la matrice. Lors du processus d'hydroflambage, le piston 7 est initialement repoussé vers le haut contre l'ébauche tubulaire en restant appliqué contre cette dernière par une force constante réglable. De cette sorte, le piston 7 sert pour ainsi dire de palpeur pour suivre les déformations transversales de l'ébauche au cours du processus d'hydroflambage.The piston 7 of a hydraulic cylinder engages in the lower branch of the T made in the matrix. During the hydroflambing process, the piston 7 is initially pushed up against the tubular blank while remaining applied against the latter by a constant adjustable force. In this way, the piston 7 serves, so to speak, as a feeler to follow the transverse deformations of the blank during the hydroflambing process.

Une pompe hydraulique 8 commande les pistons 3 et 7 par l'intermédiaire des dispositifs à tiroir 9 et 10 qui permettent de soulever et d'abaisser la partie supérieure mobile 2 de la matrice et de laisser se déplacer vers le bas en opposant une force préréglable le piston 7 lequel peut être également repoussé vers le haut en fin de processus pour dégager le T qui vient d'être fabriqué après avoir bien entendu ouvert la partie supérieure 2 de la matrice.A hydraulic pump 8 controls the pistons 3 and 7 by means of the slide devices 9 and 10 which make it possible to raise and lower the mobile upper part 2 of the matrix and to allow it to move downwards by opposing a preset force. the piston 7 which can also be pushed upwards at the end of the process to release the T which has just been manufactured after, of course, opening the upper part 2 of the matrix.

Une pompe hydraulique 11 alimente un dispositif multiplicateur de pression à pistons différentiels 12, par l'intermédiaire d'un système de commande électrique 13, le fluide à haute pression est envoyé par une canalisation à l'intérieur de l'ébauche et en passant par l'orifice 14 qui est pratiqué à l'intérieur du piston 5.A hydraulic pump 11 supplies a pressure multiplier device with differential pistons 12, by means of an electrical control system 13, the high pressure fluid is sent by a pipe inside the blank and passing through the orifice 14 which is formed inside the piston 5.

Une pompe hydraulique 15 alimente en fluide sous pression les vérins des pistons 4 et 5 qui assurent la compression axiale de l'ébauche. Un tiroir 16 permet d'inverser le mouvement de ces pistons 4 et 5.A hydraulic pump 15 supplies fluid under pressure to the cylinders of the pistons 4 and 5 which provide axial compression of the blank. A drawer 16 makes it possible to reverse the movement of these pistons 4 and 5.

Un dispositif non représenté qui peut être par exemple de type mécanique ou hydraulique fait en sorte que les déplacements des pistons 4 et 5 s'effectuent obligatoirement de manière symétrique par rapport à la matrice 1.A device, not shown, which may for example be of the mechanical or hydraulic type, causes them to move the pistons 4 and 5 are necessarily symmetrical with respect to the matrix 1.

Un calculateur électronique 17 est simultanément relié à un palpeur rhéostatique 18 qui mesure les déplacements du piston 7, à un palpeur rhéostatique 19 qui mesure les déplacements du piston 4, à un manomètre 20 qui mesure la pression à l'intérieur de l'ébauche, à un manomètre 21 qui mesure la pression agissant sur les pistons 4 et 5 et enfin au dispositif 13 qui détermine la valeur instantanée de la pression à l'intérieur de l'ébauche.An electronic computer 17 is simultaneously connected to a rheostatic probe 18 which measures the displacements of the piston 7, to a rheostatic probe 19 which measures the displacements of the piston 4, to a pressure gauge 20 which measures the pressure inside the blank, to a pressure gauge 21 which measures the pressure acting on the pistons 4 and 5 and finally to the device 13 which determines the instantaneous value of the pressure inside the blank.

Le fonctionnement du dispositif est le suivant en partant de la position représentée sur le dessin, le dispositif ne contenant pas d'ébauche.The operation of the device is as follows, starting from the position shown in the drawing, the device not containing a blank.

En agissant sur le tiroir 9 on soulève le piston 3 et la partie supérieure 2 de la matrice, ce qui permet d'introduire une ébauche tubulaire non représentée à l'intérieur de la matrice entre les pistons 4 et 5.qui comportent des organes d'étanchéité pour que l'on puisse appliquer la pression nécessaire à l'intérieur de l'ébauche.By acting on the drawer 9, the piston 3 and the upper part 2 of the matrix are raised, which makes it possible to introduce a tubular blank, not shown inside the matrix, between the pistons 4 and 5, which include organs of sealing so that the necessary pressure can be applied inside the blank.

A l'aide du tiroir 9 on fait descendre la partie mobile de la matrice pour maintenir fermement la section de tube pendant le processus d'hydroflambage.Using the drawer 9, the movable part of the die is lowered to firmly maintain the section of tube during the hydroflambing process.

A l'aide du tiroir 16 on applique longitudinalement sur l'ébauche une compression dont la valeur est déterminée par le calculateur 17 en fonction de la pression mesurée par le manomètre 21. Cette compression longitudinale de l'ébauche a pour but d'assurer l'étanchéité et de soumettre l'ébauche à une contrainte longitudinale.With the aid of the slide 16, compression is applied longitudinally to the blank, the value of which is determined by the computer 17 as a function of the pressure measured by the pressure gauge 21. The purpose of this longitudinal compression of the blank is to ensure sealing and subjecting the blank to longitudinal stress.

Le piston 7 est ramené vers le haut au contact de l'ébauche par l'intermédiaire du tiroir 10 qui maintient le piston 7 appliqué contre l'ébauche avec une force constante.The piston 7 is brought upwards in contact with the blank through the drawer 10 which holds the piston 7 applied against the blank with constant force.

Grâce au dispositif 13, le calculateur électronique provoque l'augmentation progressive de la pression à l'intérieur de l'ébauche ce qui entraîne un déplacement vers le bas du piston 7 qui est mesuré par le palpeur lequel transmet cette information au calculateur 17.Thanks to the device 13, the electronic computer causes the progressive increase of the pressure inside the blank which results in a downward displacement of the piston 7 which is measured by the probe which transmits this information to the computer 17.

Lorsque la valeur du déplacement du piston 7 a atteint une valeur prédéterminée le calculateur 17 commande le dispositif 13 qui détermine la pression à l'intérieur de l'ébauche de telle manière qu'en fonction du déplacement du piston 4 mesuré par le palpeur 19 la pression régnant à l'intérieur de l'ébauche soit déterminée en fonction d'une loi préalablement mise en mémoire dans le calculateur 17 et qui est choisie par le calculateur en fonction de la valeur de la pression à l'intérieur de l'ébauche au moment où le piston 7 a subi le déplacement de valeur prédéterminée.When the displacement value of the piston 7 has reached a predetermined value, the computer 17 controls the device 13 which determines the pressure inside the blank so that, as a function of the displacement of the piston 4 measured by the feeler 19 la pressure prevailing inside the blank is determined according to a law previously stored in the computer 17 and which is chosen by the computer according to the value of the pressure inside the blank at moment when the piston 7 has undergone the displacement of predetermined value.

Dans un premier mode de mise en oeuvre de l'invention, le processus d'hydroflambage se poursuit alors en fonction de la loi de variation de la pression interne qui a été déterminée par le calculateur 17 en fonction des critères qui viennent d'être décrits.In a first embodiment of the invention, the hydrofoaming process then continues as a function of the law of variation of the internal pressure which has been determined by the computer 17 as a function of the criteria which have just been described. .

Dans un mode de réalisation plus perfectionné de l'invention, lorsque le piston 7 a poursuivi sa course vers le bas d'une nouvelle valeur prédéterminée, le calculateur 17 mesure la pression à l'intérieur de l'ébauche à cet instant et en fonction de cette pression, choisit une nouvelle fois la loi de variation de la pression interne de l'ébauche en fonction du déplacement du piston 4 d'après la valeur de la pression interne de l'ébauche au moment où le deuxième déplacement prédéterminé du piston 7 a été atteint.In a more improved embodiment of the invention, when the piston 7 has continued its downward movement by a new predetermined value, the computer 17 measures the pressure inside the blank at this instant and as a function of this pressure, once again chooses the law of variation of the internal pressure of the blank as a function of the displacement of the piston 4 according to the value of the internal pressure of the blank at the time when the second predetermined displacement of the piston 7 was reached.

Ce processus permet de choisir éventuellement une nouvelle loi de pression interne en fonction de la compression longitudinale de l'ébauche qui est mieux appropriée que celle qui avait été choisie initialement.This process allows you to eventually choose a new internal pressure law as a function of the longitudinal compression of the blank which is better suited than that which had been chosen initially.

Ce processus d'adaptations successives peut se poursuivre à plusieurs reprises au cours de la mise en oeuvre du procédé.This process of successive adaptations can continue several times during the implementation of the method.

On remarque que le procédé qui vient d'être décrit est du type dans lequel on impose à chaque instant une pression donnée à l'intérieur de l'ébauche en fonction de la compression longitudinale de l'ébauche, et ceci en fonction d'une loi prédéterminée qui est choisie elle-même d'après la pression qu'il est nécessaire de faire régner à l'intérieur de l'ébauche pour obtenir une déformation transversale de valeur donnée.It will be noted that the process which has just been described is of the type in which a given pressure is imposed at all times inside the blank as a function of the longitudinal compression of the blank, and this as a function of a predetermined law which is chosen itself according to the pressure which it is necessary to make prevail inside the blank to obtain a transverse deformation of given value.

Grâce au procédé selon l'invention, il est possible de réaliser le processus d'hydroflambage d'une manière sûre malgré les irrégularités qui peuvent se trouver d'une ébauche à l'autre.Thanks to the method according to the invention, it is possible to carry out the hydroflambing process in a safe manner despite the irregularities which may be found from one blank to another.

On évite ainsi la plupart des rebuts qui sans cela seraient totalement inévitables.This avoids most of the rejects which would otherwise be completely inevitable.

Les lois de variation de la pression interne de l'ébauche en fonction de compression longituniale sont déterminées expérimentalement en fonction des différents types d'ébauche pour obtenir les meilleures conditions possibles d'hydroflambage, le choix de l'une de ces lois étant déterminé conformément à l'invention comme cela a été expliqué précédemment.The laws of variation of the internal pressure of the blank as a function of longitudinal compression are determined experimentally as a function of the different types of blank to obtain the best possible hydroflambing conditions, the choice of one of these laws being determined in accordance with to the invention as explained above.

Il est bien entendu que le mode de mise en oeuvre qui a été décrit ci-dessus ne présente aucun caractère limitatif et qu'il pourra recevoir toutes modifications désirables sans sortir pour cela du cadre de l'invention.It is understood that the mode of implementation which has been described above is in no way limiting and that it can receive any desirable modification without departing from the scope of the invention.

C'est ainsi par exemple que les moyens pour mesurer les déformations longitudinales et transversales de l'ébauche pourraient être différents de ceux qui ont été décrits.Thus, for example, the means for measuring the longitudinal and transverse deformations of the blank could be different from those which have been described.

De même, le choix de la loi de variation de la pression interne en fonction de la compression longitudinale pourrait également être déterminée en fonction de la déformation transversale obtenue pour une pression interne donnée.Similarly, the choice of the law of variation of the internal pressure as a function of the longitudinal compression could also be determined as a function of the transverse deformation obtained for a given internal pressure.

Enfin, il est clair que l'invention n'est pas limitée à l'obtention par hydroflambage de T mais qu'elle peut également être utilisée pour réaliser des pièces de forme différente.Finally, it is clear that the invention is not limited to obtaining T by hydroflambing but that it can also be used to produce parts of different shape.

Claims (7)

1. Procédé pour obtenir par hydroflambage des pièces de forme telles que des T ou des bulbes à partir d'ébauches se présentant sous la forme d'une section de tube ou sous une forme analogue, par application d'une contrainte mécanique dans le sens longitudinal de l'ébauche et d'une pression hydraulique à l'intérieur de celle-ci, de manière à obtenir une déformation de l'ébauche dans le sens transversal, procédé caractérisé par le fait qu'après avoir soumis l'ébauche à une compression longitudinale donnée, l'on provoque une augmentation de la pression à l'intérieur de l'ébauche pour obtenir une déformation transversale de cette dernière, et que l'on détermine en fonction de la valeur de la pression interne et/ou de la déformation transversale de l'ébauche la loi de variation que l'on fait subir ultérieurement à la pression interne de l'ébauche en fonction de la compression longitudinale à laquelle on la soumet.1. Method for obtaining by hydroflambing shaped parts such as T or bulbs from blanks in the form of a section of tube or in a similar form, by applying mechanical stress in the direction longitudinal of the blank and a hydraulic pressure inside it, so as to obtain a deformation of the blank in the transverse direction, process characterized in that after having subjected the blank to a given longitudinal compression, the pressure inside the blank is caused to obtain a transverse deformation of the latter, and which is determined as a function of the value of the internal pressure and / or of the transverse deformation of the blank the law of variation which is subsequently subjected to the internal pressure of the blank as a function of the longitudinal compression to which it is subjected. 2. Procédé selon la revendication 1, caractérisé par le fait que pour déterminer la loi de variation de la pression interne en fonction de la compression longitudinale de l'ébauche, on mesure la pression interne de l'ébauche pour une déformation transversale prédéterminée.2. Method according to claim 1, characterized in that to determine the law of variation of the internal pressure as a function of the longitudinal compression of the blank, the internal pressure of the blank is measured for a predetermined transverse deformation. 3. Procédé selon l'une des revendications 1 et 2, caractérisé par le fait que l'on choisit la loi de variation de la pression interne de l'ébauche en fonction de la compression longitudinale de celle-ci parmi un ensemble de lois prédéterminées expérimentalement en fonction des différents types d'ébauches.3. Method according to one of claims 1 and 2, characterized in that one chooses the law of variation of the internal pressure of the blank as a function of the longitudinal compression thereof from a set of predetermined laws experimentally according to the different types of blanks. 4. Procédé selon l'une quelconque des revendications précédentes caractérisé par le fait qu'au cours du processus d'hydroflambage on renouvelle à plusieurs reprises le choix de la loi de variation de la pression interne de l'ébauche en fonction de la compression longitudinale de cette dernière.4. Method according to any one of the preceding claims, characterized in that during the hydroflambing process, the choice of the law of variation of the internal pressure of the blank is repeatedly repeated. function of the longitudinal compression of the latter. 5. Dispositif pour la mise en oeuvre du procédé selon l'une quelconque des revendications précédentes, comportant une matrice susceptible de recevoir une ébauche tubulaire ou analogue et un moyen permettant de faire régner à l'intérieur de l'ébauche une-pression réglable, caractérisé par le fait qu'il comporte en outre un moyen pour mesurer les déformations transversales de l'ébauche, un moyen pour mesurer la compression longitudinale de l'ébauche, et un moyen permettant de faire varier la pression interne de l'ébauche en fonction de sa compression longitudinale selon une loi prédéterminée choisie en fonction de la valeur de la pression interne et/ou de la déformation transversale de l'ébauche.5. Device for implementing the method according to any one of the preceding claims, comprising a matrix capable of receiving a tubular blank or the like and a means allowing an adjustable pressure to prevail inside the blank, characterized by the fact that it further comprises a means for measuring the transverse deformations of the blank, a means for measuring the longitudinal compression of the blank, and a means making it possible to vary the internal pressure of the blank as a function its longitudinal compression according to a predetermined law chosen as a function of the value of the internal pressure and / or of the transverse deformation of the blank. 6. Dispositif selon la revendication 5, caractérisé par le fait que le moyen pour déterminer la compression longitudinale de l'ébauche est constitué par un palpeur rhéostatique.6. Device according to claim 5, characterized in that the means for determining the longitudinal compression of the blank is constituted by a rheostatic feeler. 7. Dispositif selon l'une quelconque des revendications 5 et 6, caractérisé par le fait que le moyen pour déterminer la déformation transversale de l'ébauche est constitué par un palpeur rhéostatiqüe.7. Device according to any one of claims 5 and 6, characterized in that the means for determining the transverse deformation of the blank is constituted by a rheostatic probe.
EP81400387A 1980-03-13 1981-03-13 Process for manufacturing workpieces by hydraulic-pressure shaping, and apparatus for carrying out this process Expired EP0036365B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81400387T ATE9283T1 (en) 1980-03-13 1981-03-13 METHOD FOR COMPRESSION FORMING OF WORKPIECES AND DEVICE FOR PERFORMING THIS METHOD.

Applications Claiming Priority (2)

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FR8005656 1980-03-13
FR8005656A FR2477918A1 (en) 1980-03-13 1980-03-13 IMPROVED PROCESS FOR MANUFACTURING PARTS BY HYDROFLAMBING AND DEVICE FOR CARRYING OUT SAID METHOD

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EP0036365A1 true EP0036365A1 (en) 1981-09-23
EP0036365B1 EP0036365B1 (en) 1984-09-12

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AT (1) ATE9283T1 (en)
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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2535987A1 (en) * 1982-11-16 1984-05-18 Vallourec Method of forming one or more bulbs by the plastic deformation during expansion of the wall of a section of pipe
FR2536680A1 (en) * 1982-11-25 1984-06-01 Sdecc T-piece pipe fitting mfr system
FR2654957A1 (en) * 1989-11-30 1991-05-31 Cuq Georges Method and device for sizing a workpiece produced by a hydraulic buckling installation
EP0633075A1 (en) * 1993-07-08 1995-01-11 Subsana-Anstalt Method and apparatus for forming hollow metallic profiles supported by internal pressure
FR2744380A1 (en) * 1996-02-06 1997-08-08 Bas En Basset Soc Ind De Fabrication of metal components by hydraulic presses
US5992197A (en) * 1997-03-28 1999-11-30 The Budd Company Forming technique using discrete heating zones
US6006568A (en) * 1998-03-20 1999-12-28 The Budd Company Multi-piece hydroforming tool
ES2154105A1 (en) * 1997-07-07 2001-03-16 Bas En Basset Soc Ind De Fabrication of metal components by hydraulic presses
EP0985465B1 (en) * 1998-09-09 2003-11-26 Kabushiki Kaisha Opton Bulging device and bulging method

Families Citing this family (2)

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Publication number Priority date Publication date Assignee Title
DE4322424C1 (en) * 1993-07-06 1994-09-15 Schaefer Maschbau Wilhelm Method and device for producing a metal hollow item according to the internal high-pressure forming process
CN107052127B (en) * 2017-06-12 2019-03-01 东营布鲁特新材料有限公司 A kind of high temperature gas expansion forming line production system and method

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US3350905A (en) * 1963-12-21 1967-11-07 Agency Ind Science Techn Liquid pressure bulge forming apparatus

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Publication number Priority date Publication date Assignee Title
FR1048482A (en) * 1950-09-18 1953-12-22 Ici Ltd Manufacture of branch pipe fittings
NL157225B (en) * 1969-12-17 1978-07-17 Tno DEVICE FOR MANUFACTURING AT LEAST ONE SPROUT ON A PIPE.

Patent Citations (1)

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US3350905A (en) * 1963-12-21 1967-11-07 Agency Ind Science Techn Liquid pressure bulge forming apparatus

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2535987A1 (en) * 1982-11-16 1984-05-18 Vallourec Method of forming one or more bulbs by the plastic deformation during expansion of the wall of a section of pipe
FR2536680A1 (en) * 1982-11-25 1984-06-01 Sdecc T-piece pipe fitting mfr system
FR2654957A1 (en) * 1989-11-30 1991-05-31 Cuq Georges Method and device for sizing a workpiece produced by a hydraulic buckling installation
EP0633075A1 (en) * 1993-07-08 1995-01-11 Subsana-Anstalt Method and apparatus for forming hollow metallic profiles supported by internal pressure
FR2744380A1 (en) * 1996-02-06 1997-08-08 Bas En Basset Soc Ind De Fabrication of metal components by hydraulic presses
US5992197A (en) * 1997-03-28 1999-11-30 The Budd Company Forming technique using discrete heating zones
ES2154105A1 (en) * 1997-07-07 2001-03-16 Bas En Basset Soc Ind De Fabrication of metal components by hydraulic presses
US6006568A (en) * 1998-03-20 1999-12-28 The Budd Company Multi-piece hydroforming tool
EP0985465B1 (en) * 1998-09-09 2003-11-26 Kabushiki Kaisha Opton Bulging device and bulging method

Also Published As

Publication number Publication date
FR2477918B1 (en) 1984-03-02
ATE9283T1 (en) 1984-09-15
FR2477918A1 (en) 1981-09-18
EP0036365B1 (en) 1984-09-12
DE3165914D1 (en) 1984-10-18

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