EP0633075A1 - Procédé et dispositif pour le formage de profils creux métalliques soutenu par pression interne - Google Patents

Procédé et dispositif pour le formage de profils creux métalliques soutenu par pression interne Download PDF

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Publication number
EP0633075A1
EP0633075A1 EP94890118A EP94890118A EP0633075A1 EP 0633075 A1 EP0633075 A1 EP 0633075A1 EP 94890118 A EP94890118 A EP 94890118A EP 94890118 A EP94890118 A EP 94890118A EP 0633075 A1 EP0633075 A1 EP 0633075A1
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EP
European Patent Office
Prior art keywords
pressure
blank
pressure medium
workpiece
pressing
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EP94890118A
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German (de)
English (en)
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EP0633075B2 (fr
EP0633075B1 (fr
Inventor
Gerfried Auer
Ernst Dr. Bitsche
Alexander Dipl.-Ing. Dr. Renner
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ELB-FORM GMBH
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SUBSANA-ANSTALT
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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
    • B21D26/037—Forming branched tubes
    • 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 invention relates to a method for the internal pressure-assisted forming of hollow metal profiles in tools for workpieces provided with bulges, neckings, branches or the like.
  • a blank attached to the tool the end faces of which have at least one movable pressing die and a stationary counter-holding tool part , preferably with two movable press rams, is brought into engagement, a liquid pressure medium is supplied, the blank is pressed with the help of the press ram (s) with bulging into at least one cavity in the tool and the pressure of the pressure medium inside the through the Press ram and stationary counter-tool part or the ram closed blank depending on the process progress during pressing, preferably depending on the ram path is controlled.
  • the invention relates to a device for performing this method, with a tool and a pressure medium supply device which is connected to a pressure medium source and which comprises a pressure medium supply line through the or one of the press rams or, if appropriate, through the stationary counter-holding tool part, and which has a pressure setting device is assigned, and to a workpiece obtained by the method according to the invention.
  • FR-A-1 048 482 and US-A-3 350 905 show such forming techniques, wherein according to FR-A-1 048 482 the pressure of the pressure medium inside the workpiece is equal to the pressure with which the press rams are applied , held or limited to a smaller value with the help of a reducing valve; according to US-A-3 350 905, on the other hand, this internal pressure can be changed with the aid of fixed control cams, which are scanned by a roller for the purpose of actuating a pressure medium pump, depending on the position of the press rams in order to avoid excessive internal pressure and thus destruction of the workpiece as the forming process progresses.
  • EP-A-36 365 discloses a method and a device of the type mentioned at the outset, with regard to the structural irregularities and wall thickness differences in the outlet pipes which are always present, the least possible rejection of the pressure deformation is to be achieved in that at least once in one Predetermined value of the longitudinal compression, i.e. the press ram path, the pressure of the pressure medium in the interior of the workpiece and / or the transverse deformation, i.e. the path of a counter-ram in the tool cavity into which the workpiece is bulged, is measured and regardless of the measurement result, the ratio of internal pressure to longitudinal compression is redefined, based on experiments previously carried out on different blank types.
  • the longitudinal compression i.e. the press ram path
  • the transverse deformation i.e. the path of a counter-ram in the tool cavity into which the workpiece is bulged
  • the inventive method of the type mentioned is accordingly characterized in that in process phases with small expansions of the material, the pressure of the pressure medium is set so that the comparative stress formed in the workpiece from the spatial stress state essentially reaches the deformation resistance of the material, whereas in process phases with large expansions, the pressure of the pressure medium is increased in order to increase the elongation at break of the material sufficiently by lowering the mean stress.
  • the flow of the material can be ensured without tearing , whereby the internal pressure guide is of crucial importance when the material flows into molded parts with a large curvature. It generally applies that the internal pressure is to be set higher, the larger the wall thickness of the blank and / or the smaller the radii of curvature which must be followed when the blank is deformed. Even with small workpiece or blank diameters, the internal pressure must be dimensioned comparatively high.
  • Such workpieces can be used, for example, as nodes in so-called "space frames” (frame structures made of aluminum or aluminum alloys which are covered with aluminum plates) in vehicle body technology are used, in which case straight or curved rods or profiles are inserted into knot pieces and welded or glued therein.
  • space frames frame structures made of aluminum or aluminum alloys which are covered with aluminum plates
  • the pressure of the pressure medium during the forming process will be controlled in more detail in such a way that in process phases in which an initial bulging, possibly a shaping of the workpiece onto variable (movable) tool parts, and the occurring comparative strains are small, the pressure together with The stresses in the workpiece caused by the press ram to the uniaxial stress state by forming the so-called comparative stress (according to Tresca or Mises) reaches the deformation resistance of the material (given the stress conditions, the next point on the so-called hyper flow surface in the stress space, which in plastic Deformation according to the flow condition of Tresca (oblique hexagonal prism) or Mises (oblique elliptical cylinder) includes all conceivable stress states during flow); in contrast, in process phases in which large strains occur, for example to replenish material in molded workpiece parts, the pressure is kept at least at such a time at all times that the resulting hydrostatic stress component (negative), which is formed in the workpiece from the spatial state of tension (negative), related to
  • the pressure medium at the beginning of the pressing process is at a low excess pressure, for example in the order of 300 to 600 bar, and towards the end of the pressing process the maximum value, for example in the order of a few kbar, is brought.
  • the internal pressure of the blank ie the pressure of the pressure medium, for example during approximately the first half of the pressing process (ie half of the path of the ram or the ram) can be more or less constant at about one third to one fifth of that provided towards the end of the pressing process Maximum values can be kept, and then from about half the pressing process the internal pressure can be increased gradually, for example linearly, up to the maximum pressure at the end of the pressing process.
  • the reference stress resulting from the internal pressure and the stresses from the pressing and frictional forces must reach the material's resistance to deformation.
  • the pressure medium is brought to a maximum pressure of at least 80% of the tensile strength of the material of the blank during the pressing process.
  • the pressure control depends in detail on the type and shape of the workpiece to be produced, and it can advantageously be provided here that the pressure of the pressure medium in pressing phases in which the blank material flows around small radii of curvature of the tool, depending on the wall thickness, to 5%. -40% of the maximum pressure during pressing is set (the reference stress reaches the deformation resistance). The maximum internal pressure is reached outside of these phases.
  • the pressure medium is already at an increased preload pressure, preferably 5% -20%, in particular before the blank is pressed about 10% of the maximum pressure reached during pressing, e.g. is brought to a value in the order of 100 to 1000 bar.
  • Such prestressing of the pressure medium is particularly important for the initial problem-free bulging of the blank, the value of the prestressing pressure being selected as a function of the buckling stress of the material to be deformed; in particular, the internal pressure is to be determined in such a way that there is no buckling at the point of the bulge to be produced, which could happen if the pressure medium is not preloaded, in particular when processing wall thicknesses which are small in relation to the other dimensions of the hollow profile.
  • the blank is filled with the pressure medium free of gas inclusions before the pressing process, and if the pressure medium is brought to an increased pressure by a pump. If there were gas inclusions in the - liquid - pressure medium, the compression and expansion of the gas inclusions would not make it possible to achieve the desired pressure increase or reduction and thus impair the exact pressure control sought.
  • the blank In order to ensure the desired exact pressure control from another point of view, namely the point of view of closing the blank during the pressing process, in order to ensure the increased internal pressure, the blank must be sealed as well as possible on its end faces.
  • press seals with step-shaped shoulders on the front edges can be used to seal the blank tightly, which have a height of 5% -100% of the mean wall thickness of the blank, and with which the material of the blank is plasticized to produce a metallic seal.
  • an advantageous embodiment of the method according to the invention is characterized in that, in the case of blank materials which have alloy components at the grain boundaries, in particular high-strength aluminum alloys, a heat treatment is carried out before the pressing process in such a way that by storing these alloy components in the grain lattice increases the ductility of the material, and that the pressing process is carried out within a predetermined time window, for example 1 hour to 4 hours after the heat treatment, but before the alloy components are again outsourced to the grain boundaries.
  • blanks made of AlMgSi alloys are heated at about 400 ° C. for about 100 minutes in an annealing furnace, then cooled in air and pressed in about 3 hours after the end of the annealing furnace heat treatment.
  • the duration of the actual pressing process is in the range of one or a few minutes, often less one minute, including the previous filling with the pressure medium.
  • the pure pressing time can therefore sometimes be as little as 20 s to 30 s.
  • variable counter tool part which has a cross-sectional shape corresponding to the (respective ) has to be bulged, held against it, and it is particularly advantageous according to the invention here if the (respective) variable tool part is held in a pressure-controlled and / or displacement-controlled manner and the force introduced into the workpiece is dimensioned such that the total occurring in the workpiece mean stress (the hydrostatic stress component) is reduced to such an extent that the elongation at break thereby determined becomes greater than the greatest strain occurring in the workpiece part in question supported by the variable tool part.
  • variable counter-holding tool part (s) for supporting bulged workpiece parts is all the more important, the more brittle the material and the smaller the wall thickness.
  • the counter support creates a hydrostatic stress component in the adjacent outer fiber of the workpiece, which increases the possible, exploitable elongation at break (especially in the case of brittle materials), so that the greatest comparative strains occurring in these areas become smaller than the elongation at break. This prevents the workpiece from bursting.
  • the blank has a wall thickness less than 10% of the equivalent diameter D ers (as defined above) or if materials with a brittle fracture toughness less than 50 MN ⁇ m -3/2 or materials with a Tensile strength Rm less than 350 N / mm2 can be used.
  • Such countermeasures are also favorable in the case of bulges which are to be produced unevenly with respect to the cross section and which have small radii of curvature on parts of the surface, in particular less than 10% of the named replacement diameter D ers .
  • control of the force directed against the workpiece and transmitted by the variable counter-holding tool parts is to be aimed for, in the case of the fiber (the outer fiber) of the workpiece which is in contact with the respective variable counter-holding tool, a hydrostatic force related to the deformation resistance Stress component is caused, the elongation at break according to the corresponding material characteristic is greater than the greatest comparative elongation occurring there at any time.
  • variable counter-holding tool part is at least 5% of the force exerted by the internal pressure on the part to be bulged out at any point in the process, in particular even at the start of the process.
  • the process lubrication is also important, since there is a large friction surface in relation to the volume of material formed.
  • a corresponding application of lubricant is therefore particularly important at the edges of the semi-finished products. It has proven to be advantageous here if in zones with a small radius of curvature of the blank or tool, in particular on rounded edges, at least 50% more lubricant is applied than on the other parts of the blank or tool.
  • a pressure medium source per se could be used, from which the pressure medium is delivered at a controllable pressure, this pressure medium of variable pressure being supplied to the interior of the blank.
  • this pressure medium of variable pressure being supplied to the interior of the blank.
  • a particularly simple and effective device of the type mentioned at the outset is characterized according to the invention in that a pressure medium discharge line leads through the (other) press ram or, if appropriate, the stationary counter-holding tool part, and in that the pressure setting device is accommodated in this pressure medium discharge line.
  • the pressure medium is therefore supplied from a pressure medium source with a constant, high pressure per se, and the pressure setting is carried out in the discharge line, a controlled pressure valve preferably being used for this purpose.
  • a pump supplying the pressure medium with a predetermined high pressure can simply be provided as the pressure medium source, and then a check valve is advantageously accommodated in the pressure medium supply line, so that the pressure medium cannot be pushed back from the interior of the blank to the pump.
  • a workpiece made of brittle material for example with a brittle fracture toughness of less than 30 MN.m -3/2 , in particular made of an aluminum alloy, can be obtained for the first time with the method according to the invention, and such a workpiece is thus also the subject of the invention.
  • a blank is shaped in a conventional manner from a tube with a circular cross-section to a workpiece 1 with a bulge in the form of a T-piece, the workpiece 1 in a stationary tool 2 with the aid of press dies 3 placed on the end face, 4 is pressed.
  • the pressing force that is exerted on the workpiece 1 with the pressing dies 3, 4 is illustrated schematically with arrows 5 and 6, respectively.
  • the workpiece 1 is filled with a liquid pressure medium before the forming or pressing, after which the two press rams 3, 4 are brought into engagement with the end faces of the workpiece 1 and the pressing process begins.
  • a corresponding internal pressure builds up in the workpiece 1, which supports the material of the workpiece 1 from the inside, whereas the tool 2 provides external support. In this way, the material of the workpiece 1 is caused to flow into the cavity 7 in the workpiece 2.
  • the workpiece 1 is supported from the inside with the aid of the pressure medium that has been filled into the workpiece 1, as is schematically illustrated by arrows 8 in FIG.
  • the following relationship applies to the strain ⁇ in the material of the workpiece 1 in the area of the outer fiber 9 or the inner fiber 10:
  • Inner fiber: ⁇ i ln (1 + w / (2r + w))
  • Outer fiber: ⁇ a ln (1 - w / (2r + w))
  • w denotes the wall thickness of the workpiece 1
  • r denotes the radius of curvature around which the material flows along the tool 2.
  • the neutral fiber is otherwise indicated at 11 in FIG.
  • the mean stress ⁇ m is also referred to in the literature as the hydrostatic stress component.
  • the deformation resistance k f is usually only from the change in shape as well as the temperature during forming, but in special cases the rate of deformation can also affect the resistance to deformation k f .
  • Essential to the invention is the physical effect that the pressure expansion (that is the greatest possible positive or negative expansion, which allows material, temperature and stress state) of a plasticizable material by lowering the hydrostatic stress component (possibly related to the strain resistance, in order to increase the deformation history) capture) can be increased significantly.
  • FIG. 3 An arrangement for internal pressure-assisted forming with such a pressure control is now illustrated very schematically in FIG.
  • FIG. 3 just like in FIG. 7 to be explained - components corresponding to the respective components of FIG. 1 are designated with the same reference numerals.
  • a movable tool part 13 for counter-holding is arranged in the tool cavity 7 to support the bulged workpiece part 12, this movable or variable counter-holding tool part 13 being referred to below as a counter-holding stamp for the sake of simplicity.
  • the counter-holding force of this counter-holding die 13 is indicated by Fg, whereas the pressing force of the pressing dies 3, 4 is indicated by Fp1 and Fp2.
  • the internal pressure in the interior of the workpiece 1 is indicated by pi, this internal pressure pi being controlled as a function of the path s of the press rams 3, 4 during the course of the process. Accordingly, the press rams 3, 4 are assigned in the drawing, not illustrated in more detail, of conventional design per se, so as to detect the path s of the press rams 3, 4 at any time.
  • the internal pressure pi (s) is set with the aid of a pressure valve 14 which is arranged in a pressure medium discharge line 15 leading through the upper press ram 3, a control valve 16 being connected upstream of it and having two positions - filling or Presses - owns.
  • a pressure medium supply line 17 runs through the other - lower - press ram 4, through which a controllable pump 18, which is driven by a motor 19, supplies the liquid pressure medium - preferably simply water - to the interior of the workpiece 1.
  • a check valve 20 is furthermore arranged in the pressure medium supply line 17.
  • the shape of the die or tool 2 also called shape, can be seen in more detail, whereby it can be seen that the externally circular tool 2 has an elongated interior or molding space 21 of a square shape Cross-section, for the workpiece 1 having a square cross-section, and furthermore the cavity 7 of a rectangular cross-section branching therefrom for the bulge or branch 12 of the workpiece 1 to be produced.
  • a blank ie a hollow profile with a square cross-section, from which the workpiece 1 with the branch 12 is to be formed, is inserted into the tool 2, after which the two press rams 3, 4 are brought into engagement with the end faces of the blank, a tight seal on these end faces being brought about with the aid of the press rams 3, 4.
  • the press rams 3, 4 can be stepped on their end faces on the outer circumference, ie have step-shaped shoulders, which in particular have a height in the range from 5% to 100% of the mean wall thickness of the blank, and with which the material of the blank during pressing is plasticized, whereby a metallic seal is brought about.
  • the pump 18 is switched on in order to supply pressure medium, in particular water, to the interior of the blank via the pressure medium supply line 17.
  • the valve 16 on the outlet side is in the "fill" position as shown, it being easy to determine in this position when the pressure medium exits on the outlet side (as is schematically illustrated in FIG. 3 with the outlet line 22).
  • the control valve 16 is then adjusted upward into its “pressing” position, as shown in FIG. 3, in which a connection to the pressure valve 14 instead of to the outlet line 22 is established on the outlet side.
  • the pressure of the pressure medium is now increased with the aid of the pump 18, and the pressing process can begin by driving the press rams 3, 4 with the pressing force Fp1 or Fp2. This results in the aforementioned tight sealing of the end faces of the blank by the press rams 3, 4, by plasticizing the blank material, and during the pressing, the internal pressure pi of the pressure medium is increased by the upsetting process.
  • the internal pressure pi (s) is continuously adjusted with the help of the pressure valve 14, starting with a preload pressure at the beginning of the pressing, a pressure increase to approximately twice the preload pressure can be provided, after which, for example, a linear pressure increase in a next section of the process about ten times the pressure value - up to about the middle of the entire pressing process, ie half way the press ram 3, 4 - is provided; the internal pressure pi is then kept constant, for example, at this maximum value that has now been reached.
  • the bulge or branch 12 is produced, with the counter-punch 13 being held here with a counter-holding force Fg, which is preferably also controlled as a function of the path, in order to prevent the bulge 12 from bursting or bursting.
  • FIG. 6 shows a diagram of the internal pressure pi (in bar) over the path s (in mm) of the press rams 3, 4, the internal pressure pi generally being controlled as a function of the path as set out above.
  • a preload pressure pv of, for example, 130 bar is set at the beginning of the pressing process, and when the pressing begins, the internal pressure pi increases to a value pa of e.g. 250 bar, which is kept constant up to a press ram path s of 7.5 mm (phase of molding on the punch 13 and beginning bulge with still small expansions).
  • a workpiece 1 'with two branches 12', 12 '' can also be produced with a fundamentally similar internal pressure curve as shown in FIG. 6, as is illustrated in the diagram of FIG.
  • the tool 2 ' has two cavities 7', 7 '' for the bulges or branches 12 ', 12' ', with corresponding counter-holding punches 13', 13 '' in these cavities 7 ', 7' 'as variable tool parts a contact pressure Fg1 (s) or Fg2 (s) are kept movable.
  • the press rams 3, 4 are applied to the workpiece 1 'with a pressing force Fp1 or Fp2.
  • a supply line 23 is provided, to which the pressure medium supply line 17 is connected via a directional control valve 24 and on the one hand via the pump 18 or on the other hand directly via a check valve 25.
  • a pressure valve 14 ' is in turn connected to the pressure medium discharge line 15, which in the present case is controlled via a hydraulic control circuit Pump 26 and a control line 27, in which a check valve 28 is received, can be adjusted in pressure.
  • control and regulating unit 30 which controls the process water preload pump 18 and the pump 26 which can be adjusted with regard to the outlet pressure in the control circuit for the pressure valve 14 'for the purpose of setting the respective internal pressure pi.
  • Input variables for the control and regulating unit 30 are the path s of the press rams 3, 4 (it is usually sufficient to take the path of a press ram, for example 3, and feed them to the unit 30) and the internal pressure pi (see also for safety reasons) ).
  • a control or regulation can be provided as desired, and accordingly the sizes Fp1, Fp2, Fg1 and Fg2 according to Fig. 7 are both recorded and set, e.g. simply path-dependent or with an additional readjustment (actual value-target value comparison), as will be explained in more detail below with reference to the flow diagrams from FIGS. 8 to 10.
  • the unit 30 could be a PLC (programmable logic controller) unit, with which the pressing pressures (pressing forces Fp1, Fp2, Fg1, Fg2) and in particular the internal pressure pi can be set simply as a function of the path.
  • PLC programmable logic controller
  • FIG. 8 A corresponding flow chart is shown in FIG. 8, which includes such a simple path-dependent pressure control and counterforce control.
  • the workpiece 1 ' is filled in block 33 until the pressure medium emerges at the outlet of the pressure valve 14'.
  • the valves v1 and v2 are set in accordance with block 35 in FIG. This starts the actual pressing process, during which the path s of the press ram 3, 4 is measured, see Block 36 in Fig. 8.
  • the pressure relief valve 14 'for the internal pressure pi is continuously set depending on the path s, block 37 in FIG. 8.
  • block 39 it is queried cyclically whether the press ram path s has reached the end value for it, ie whether the pressing process can be ended or not. If this is not the case, the process returns to block 36, etc. at 40, and a new path measurement, pressure relief valve position, etc. takes place. If the press ram path has reached its end value sEnd, the end of the process sequence follows after block 39, as in FIG 8 is indicated at 41.
  • FIG. 9 illustrates a somewhat modified process flow compared to FIG. 8, in that an internal pressure-dependent regulation for the counter-stamping forces Fg1 and Fg2 takes place.
  • Steps 31 to 37 are the same as in the flow chart according to FIG. 8, so that a new description of the same can be omitted.
  • step 37 setting the internal pressure pi
  • Fg1 and Fg2 i.e.
  • a setpoint Fg1 (pi) and a setpoint Fg2 (pi) are defined and compared with the actual value Fg1ist or Fg2ist.
  • the valves for actuating the counterhold punches 13 'or 13' 'are set block 43 in Fig. 9. Then in block 39 it is again queried whether the press punches have already reached their end of travel, and if not, the process returns to block 39, if so, the end 41 is reached.
  • steps 31 to 35 which in turn are identical, are followed by a modified measuring step at 36 ', where not only the ram path s but also the ram forces Fp1 and Fp2 are measured.
  • valves for the counter-holding punches 13 'or 13' '(Fg1, Fg2) are again set, analogously to FIG.
  • the rest of the procedure is the same as that of Fig. 8 or 9.
  • FIG. 11 schematically shows a device with a tool 2 without variable tool parts (counter-punch) in a cavity 7, for example a hemispherical bulge 12 on the workpiece 1 'during the pressing using the press punches 3, 4.
  • a heat treatment of the blank to be pressed is desired before the pressing process - as a rule, such a heat treatment is preferred for soft annealing - the duration and the degree of heat treatment (temperature) naturally depend on the respective blank, in particular on the respective material.
  • heat treatment will have to be carried out in such a way that the blank is sufficiently long, e.g. 1 to 2 hours, heated to a few 100 ° C in an annealing furnace, after which it is allowed to cool in air; Before the so annealed material would lose ductility again due to the removal of alloy components to the grain boundaries, the pressing process - e.g. about 2 or 3 hours after the heat treatment.
  • the upright arrangement of the tool shown in FIGS. 3 and 7 with the supply of the pressure medium from below has the advantage that when filling, air bubbles or gas bubbles in general can rise upwards, so that the interior of the blank or workpiece 1 or 1 ' can be filled without gas bubbles can.
  • Adequate lubrication is also important when pressing, particularly in places with a strong curvature where the material has to flow around tight radii or into tight radii.
  • Appropriate lubricant application is therefore particularly important on edges - including the blank. In particular, it is advantageous to apply around 50% more lubricant in the edge area.
  • a hollow profile blank with a square cross section was pressed from an AlMgSi 0.5 material, the dimensions of the blank being as follows: external dimensions 30 ⁇ 30 mm2, wall thickness 2 mm, corner radius 2 mm, length 155 mm.
  • the tensile strength for AlMgSi 0.5 is approx. 200 N / mm2.
  • the blank Before being pressed, the blank was heated to 400 ° C. in an annealing furnace for 100 minutes and then cooled in air. The press processing took place after approx. 3 hours. A preload pressure of 130 bar was set for this (at the beginning of the pressing process), and the maximum internal pressure that was reached in the second half of the process phase, where large expansions of the material of the workpiece were required, was 2000 bar.
  • the pressing speed was 5 mm / s and the counter-holding force of the one counter-holding die for the production of a workpiece with a branch, square as the starting profile, was 10 kN.
  • the workpiece produced was a T-piece, similar to that shown in FIG. 3, with a branch length of 53 mm (measured against the rear wall), and the workpiece had a final length of 90 mm. In the area of the junction, the corner radius was 3 mm.
  • a wide variety of conventional pressure valve types can be used as the pressure valve 14 and 14 ', in particular, in addition to the hydraulically operated pressure valve 14' shown in FIG. 7, also electromagnetically operated pressure valves.
  • the control and regulating unit 30 can furthermore be implemented in a conventional manner with corresponding electrical circuits, such as, in particular, A / D converters, D / A converters, comparators and / or microprocessors.
  • electrical circuits such as, in particular, A / D converters, D / A converters, comparators and / or microprocessors.
  • Such regulating and control units are basically known per se in conventional presses, so that a detailed explanation can be omitted here.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Forging (AREA)
EP94890118A 1993-07-08 1994-07-08 Procédé pour le formage de profils creux métalliques soutenu par pression interne Expired - Lifetime EP0633075B2 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AT1346/93 1993-07-08
AT0134693A ATA134693A (de) 1993-07-08 1993-07-08 Verfahren zur innendruckgestützten umformung von metallischen hohlprofilen sowie vorrichtung zur durchführung dieses verfahrens
AT134693 1993-07-08

Publications (3)

Publication Number Publication Date
EP0633075A1 true EP0633075A1 (fr) 1995-01-11
EP0633075B1 EP0633075B1 (fr) 1997-04-09
EP0633075B2 EP0633075B2 (fr) 1999-12-22

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EP94890118A Expired - Lifetime EP0633075B2 (fr) 1993-07-08 1994-07-08 Procédé pour le formage de profils creux métalliques soutenu par pression interne

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EP (1) EP0633075B2 (fr)
AT (2) ATA134693A (fr)
DE (1) DE59402350D1 (fr)
ES (1) ES2102801T5 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1010480A1 (fr) * 1998-12-18 2000-06-21 Tubes et Formes Procédé et dispositif de réalisation par hydroformage d'un piquage incliné à partir d'un tube métallique
EP0985465B1 (fr) * 1998-09-09 2003-11-26 Kabushiki Kaisha Opton Dispositif et procédé de déformation
US7832244B2 (en) 2008-03-13 2010-11-16 Gm Global Technology Operations, Inc. Controlling fluid pressure in a hydroforming process

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1048482A (fr) * 1950-09-18 1953-12-22 Ici Ltd Fabrication de raccords de tuyaux à branchements
US3350905A (en) * 1963-12-21 1967-11-07 Agency Ind Science Techn Liquid pressure bulge forming apparatus
EP0036365A1 (fr) * 1980-03-13 1981-09-23 VALLOUREC Société Anonyme dite. Procédé perfectionné pour fabriquer des pièces par hydroflambage et dispositif pour la mise en oeuvre de ce procédé

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2331430A (en) † 1941-08-27 1943-10-12 Chase Brass & Copper Co Apparatus for making hollow articles
GB1083354A (en) † 1963-12-21 1967-09-13 Agency Ind Science Techn A liquid pressure bulge forming apparatus and process

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1048482A (fr) * 1950-09-18 1953-12-22 Ici Ltd Fabrication de raccords de tuyaux à branchements
US3350905A (en) * 1963-12-21 1967-11-07 Agency Ind Science Techn Liquid pressure bulge forming apparatus
EP0036365A1 (fr) * 1980-03-13 1981-09-23 VALLOUREC Société Anonyme dite. Procédé perfectionné pour fabriquer des pièces par hydroflambage et dispositif pour la mise en oeuvre de ce procédé

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0985465B1 (fr) * 1998-09-09 2003-11-26 Kabushiki Kaisha Opton Dispositif et procédé de déformation
EP1010480A1 (fr) * 1998-12-18 2000-06-21 Tubes et Formes Procédé et dispositif de réalisation par hydroformage d'un piquage incliné à partir d'un tube métallique
FR2787357A1 (fr) * 1998-12-18 2000-06-23 Tubes Et Formes Procede et dispositif de realisation par hydroformage d'un piquage incline a partir d'un tube metallique
US6202460B1 (en) 1998-12-18 2001-03-20 Tubes Et Formes Method and device for producing a Y-fitting from a metal tube by hydroforming
US7832244B2 (en) 2008-03-13 2010-11-16 Gm Global Technology Operations, Inc. Controlling fluid pressure in a hydroforming process

Also Published As

Publication number Publication date
ES2102801T3 (es) 1997-08-01
DE59402350D1 (de) 1997-05-15
EP0633075B2 (fr) 1999-12-22
EP0633075B1 (fr) 1997-04-09
ES2102801T5 (es) 2000-04-16
ATA134693A (de) 1999-10-15
ATE151317T1 (de) 1997-04-15

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