EP0169564A2 - Procédé et dispositif pour plier des objets longs, en particulier des tubes - Google Patents

Procédé et dispositif pour plier des objets longs, en particulier des tubes Download PDF

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Publication number
EP0169564A2
EP0169564A2 EP85109332A EP85109332A EP0169564A2 EP 0169564 A2 EP0169564 A2 EP 0169564A2 EP 85109332 A EP85109332 A EP 85109332A EP 85109332 A EP85109332 A EP 85109332A EP 0169564 A2 EP0169564 A2 EP 0169564A2
Authority
EP
European Patent Office
Prior art keywords
workpiece
zone
cooling
inductor
cross
Prior art date
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.)
Withdrawn
Application number
EP85109332A
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German (de)
English (en)
Other versions
EP0169564A3 (fr
Inventor
Jelke Ringersma
Johannes Marinus Hofstede
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cojafex BV
Original Assignee
Cojafex BV
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Cojafex BV filed Critical Cojafex BV
Publication of EP0169564A2 publication Critical patent/EP0169564A2/fr
Publication of EP0169564A3 publication Critical patent/EP0169564A3/fr
Withdrawn legal-status Critical Current

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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
    • B21D7/00—Bending rods, profiles, or tubes
    • B21D7/02—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment
    • B21D7/024—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment by a swinging forming member
    • B21D7/025—Bending rods, profiles, or tubes over a stationary forming member; by use of a swinging forming member or abutment by a swinging forming member and pulling or pushing the ends of the work

Definitions

  • the invention relates to a method for bending elongated workpieces, in particular pipes, according to the preamble of claim 1, and to a device for carrying out the method according to the preamble of claim 11.
  • the inductively heatable and thus electrically conductive elongated workpieces come in addition to the Tubes in particular also include rods and, more generally, all such elongated workpieces which can be bent along the circumference of a heated, usually narrow, circumferential zone due to uneven temperature distribution.
  • Extrados is not only beneficial; because the risk of cracking is reduced there, but less stretching means less thinning of a pipe wall.
  • Extrados is not only beneficial; because the risk of cracking is reduced there, but less stretching means less thinning of a pipe wall.
  • Heating elongated workpieces e.g. Pipes by means of an inductor for their progressive bending are widely known, e.g. generally seen from NL-PS 142 607 and DE-PS 2 112 019.
  • the uneven heating by means of an inductor for the progressive bending of pipes and other elongated workpieces with the aim of influencing or correcting the degree of deformation or wall thickness change is known according to a first embodiment from DE-PS 2 738 394, which provides an asymmetrical arrangement of the inductor. Similar aims one of several alternative embodiments of DE-OS 22 20 910, according to which the part of the inductor enclosing the extrados should have a greater distance from the pipe surface than the part enclosing the intrados.
  • DE-OS 22 20 910 For the same purpose from DE-OS 22 20 910, second alternative, the possibility is known of achieving an uneven or asymmetrical heating by means of laminated cores which are attached locally in the vicinity of the inductor and which serve as yoke plates and by means of which the intensity of the inductive heating is influenced can.
  • an inductor is known from US Pat. No. 4,177,661, in which part of the induced energy is collected by a shield which is placed between the inductor and a pipe to be bent.
  • a device is also described there according to which an extra heating source is applied to the Intrados in front of the ring-shaped and inductively operating heating source.
  • the asymmetrical heating by means of eccentric installation or radial adjustment of the inductor has the disadvantage that when the inductor is adjusted transversely to lower the temperature of the extrado, the temperature of the intrado is increased at the same time, although in order to avoid undesired thinning of the wall, for example a pipe on the extrado, The temperature would only need to be changed on the extrados and excessive compression on the intrados would also not be desirable.
  • the inductors used usually have spray holes which spray water at a certain angle in the forward direction onto the pipe which has already been bent, in order to limit the heated zone. By transverse adjustment of the inductor also changes the place where the water jets hit the tube, with the result that the width of the heated zone becomes uneven and this has an adverse effect on the bend.
  • Locating an extra heat source locally with the purpose of achieving a higher temperature on the inside of the arch, i.e. on the intrados, has the disadvantage that the heated zone is made extra wide at this point, which is disadvantageous for maintaining a good round Tube (missing bulges or upsetting points) during bending.
  • the invention proceeds generically from the possibility either to set up the inductor eccentrically in accordance with the notorious prior art for asymmetrical inductive heating of the workpiece (for example DE-PS 2 738 394) or to partially shield the induction in the case of concentric installation (US Pat. No. 4,177) 661).
  • the former Fall does not allow a concentric inductor arrangement a priori; the second case is complex and difficult to implement.
  • the genus can also be read on the arrangement with yoke plates according to DE-OS 22 20 910, which, however, can only be matched precisely to a specific workpiece in a very inefficient manner.
  • the invention is therefore based on the object of providing a method and a device for bending elongated workpieces, in particular pipes, with uneven temperature distribution along the circumference of an inductively heated cross-sectional zone of the workpiece, which allow a concentric or almost concentric inductor installation and make it possible in a simple manner to set different bending radii with the same inductor.
  • the invention enables the inductor to be strictly or approximately concentrically around the workpiece, i.e. with approximately the same radial distance with respect to the object to be bent, e.g. a pipe, and in the peripheral region of the workpiece, where a lower temperature is desired, to branch the inductor into two or more parallel currents and to completely or partially dissipate the heating energy induced by the branched partial currents in the object to be bent , e.g. by means of the usual spraying directed and adjustable water jets.
  • the implementation of the invention is relatively simple, without having to rely on an asymmetrical arrangement of the inductor with respect to the tube.
  • a radial transverse adjustment with changing bending radii which can be implemented with the same inductor, is usually not at all and at least less frequently and to a lesser extent than in known methods and devices.
  • the necessary adjustments can be made based on the location and extent of the cooling.
  • Virtually any desired temperature profile can be set along the circumference of the heated cross-sectional zone of the workpiece, so that undesired upsets on the intrados can also be avoided.
  • the wall thickness can be particularly well controlled .
  • the induction loop also mentioned in the generic term is usually a single loop. In practice, however, the individual loop can be assembled into a wider inductor loop, for example by bridging two parallel induction loops with a connecting plate. A repeated loop through the screw shape of the inductor is less common without it also being excluded from the outset (e.g. mentioned in the generic DE-OS 22 20 910).
  • the temperature reduction by branching the inductor will only be provided on the stretch side of the arc, the so-called extrados.
  • the reverse possibility should at least theoretically be included if the teaching of DE-PS 28 22 613 should still make a technical sense, according to which a reverse temperature application is provided.
  • the branching will extend over about half the circumference of the pipe or the circumference of the other workpiece. It is entirely possible to overlap the stretching zone on both sides, which is covered qualitatively with the upper limit of 60% of the circumference of the workpiece, which is not to be taken exactly numerically. It is possible with much simpler and more variable means than in the generic DE-OS 22 20 910, as aimed there to bring only about a quarter of the circumference to a low temperature and the rest to a higher temperature, in particular the forging temperature.
  • the heating cross section does not necessarily have to be arranged perpendicular to the workpiece axis, but can also run obliquely or kinked, for example, according to FIGS. 4 and 5 of DE-OS 22 10 715.
  • the invention is also invariant with regard to the way in which the bending moment is applied. It is thus possible both to move the workpiece axially relative to the stationary inductor and, conversely, to shift the inductor relative to the stationary workpiece or even to make both elements displaceable and to focus only on a relative movement.
  • the bending moment can be either by axially pressing on the unbent tube (DE-PS 27 38 394) or by introducing it a torque on the bending arm (see. DE-OS 19 35 100) or else, for example after a flash bow tension (see. US-PS 783 716), are applied.
  • inductors with a round cross section but also e.g. those with angular, in particular approximately rectangular, triangular or trapezoidal, cross-section are used, the profile being able to be both transverse and longitudinal to the connections.
  • the inductor can be branched, for example, by a right-angled fork-like bend. Streamlined oblique bends are preferred, which not only have flow-related advantages, but at the same time can also represent an adaptation to the different heating along the circumference of the workpiece.
  • induction frequencies between 500 and 1000 Hz can be used. 1000 Hz has a penetration depth of approx. 16 mm for steel pipes, 500 Hz a penetration depth of approx. 22 mm.
  • the relatively high frequencies for thin-walled pipes and the relatively low frequencies for thick-walled pipes are used. In borderline cases, lower or higher frequencies can also be used.
  • These two or more partial flows can all be arranged on the same side of the inductor, in particular if they are to be used to control or regulate the desired conditions and for this purpose require a larger area, for example in order to distribute the cooling liquid over a wider area.
  • At least one neighboring zone of the heating cross section which is covered by the partial flows, and in which a complete or partial cancellation of the inductive heating takes place, is arranged in the bent part of the workpiece.
  • Both cooling for deterrence and cooling in the sense of the invention for the partial abolition of inductive heating can also be carried out from the inside of a pipe if necessary.
  • Fig. 1 shows the basic principle which is applied to a bending device and is intended to serve as a starting point for an explanation of the invention.
  • a pipe 1 (only as an example) to be bent is passed through a fixed guide 2 in the direction of arrow P (exerting a compressive force P for the pipe feed) through an inductor 3, which heats the pipe up to a temperature in the narrow zone 4 , in which the tube 1 can experience the desired deformation at this point.
  • the tube is cooled by a circle of water jets 5 directed obliquely forward (in the direction of advance of the tube) and exiting from the inductor 3, for example, and conducted in an arc 6 around the point 7, at which the bent part is at one around the point 7 freely rotatable arm 8 be rigid is consolidated.
  • the already bent pipe part 6 practically forms a rigid unit and thus a lever, which is always perpendicular or almost perpendicular to the longitudinal direction of the unbent pipe section, a line perpendicular to the pipe leading through the heated zone 4 and the pivot point 7 .
  • a compression effect occurs on the inside 9 of the sheet, the so-called intrados, and a stretching action occurs on the outside 10 of the sheet, the so-called extrados.
  • the degree of upsetting and stretching depends on the bending radius R and on the temperature or the deformation resistance of the material to be bent at the different points.
  • FIGS. 2a and 2b A conventional inductor 3, as can usually be used in the bending device according to FIG. 1, is shown in FIGS. 2a and 2b. It has a tube 12, bent into a simple circular induction loop 11 in one plane, made of a material which is conductive for medium-frequency current (500 to 1000 Hz), for example copper or a copper alloy.
  • the free internal cross section of the induction loop 11 is dimensioned such that the tube 1 can be passed through it approximately coaxially to the induction loop at a radial distance therefrom according to FIG. 1.
  • two connecting tubes 13 protrude radially from the induction loop 11. They are bent somewhat apart at their free ends and each carry a connecting flange 14 at their free ends.
  • the connecting flanges 14 serve for connection to an inductor power supply unit (not shown) working with the medium frequency mentioned, and also expediently for connection to a cooling water source. This applies in particular if spray nozzles for the cooling water jets 5 according to FIG. 1 are formed in the induction loop 11 axially forwards and radially inwards.
  • the inductor tube 12 also serves as a cooling water line for cooling water which is passed from one connecting flange 14 to the other. If the Inductor 3 should not also serve as a cooling water spray element, the same cooling water flow (or flow of a different cooling fluid) can serve to cool the inductor.
  • FIGS. 2a and 2b show an inductor modified according to the embodiment of FIGS. 2a and 2b according to the invention.
  • the inductor tube 12 forms a circular induction loop 11, which is connected to the connecting tubes 13 at a circumferential point.
  • the relationships are essentially the same as in the embodiment of Figs. 2a and 2b, so that the description, e.g. with regard to the connecting flanges 14, which are no longer shown separately.
  • the special feature according to the invention consists of the following:
  • bypass line 15 merges directly into the connecting pipes 13 here.
  • the free ends of the induction loop 11 are each connected to the associated connecting pipe 13 by an oblique connecting tube 16 and the free ends of the bypass line 15 are each connected to the adjacent section of the induction loop 11 by an oblique connecting tube 17.
  • the level of the bypass line 15 coincides with the level of the connecting pipes 13, while the induction loop 11 is axially offset.
  • the direction of inclination of the connecting pipes 16 and 17 corresponds to the direction of flow indicated by arrows of the coolant flowing through the inductor 3.
  • FIGS. 4 and 5 now show two modifications of the inductor of FIGS. 3a to 3c in an application in which the inductor itself serves as a coolant source acting on the tube 1.
  • the basic structure of the inductor 3 is the same as in FIGS. 3a to 3c. Particularly noteworthy / is, however, a certain sequence in FIGS. 4 and 5 of the circular induction loop 11 on the one hand and the bypass line 15 on the other hand with respect to the direction of displacement of the tube 1, which here corresponds to the direction of the arrow P exerting pressure.
  • the inductor 3 is itself a spraying device for cooling water jets 5 acting on the pipe 1
  • the two alternative arrangements of FIGS. 4 and 5 also result in a different arrangement of the spraying nozzles.
  • the circular induction loop 11 is arranged in the direction of displacement of the tube 1 in front of the bypass line 15.
  • the induction loop 11 causes a narrow heating zone 4 in the tube 1 at right angles to the axis of the tube in the sense of claim 1
  • Direction front ie the edge of the heating zone 4 facing the already bent tube, is generated by a first row of water jet nozzles 18 formed on the induction loop 11, which emit the water jets 5 in the sense of FIG. 1 obliquely forward and radially inward onto the tube 1 and form said quenching edge of the heating zone 4 thereon.
  • two further water jets 5a and 5b directed obliquely forward and radially inwards onto the tube 1 are used from two further rows of water jet nozzles 19 and 20 which face the bent tube 1 on the one hand are still distributed on the front flank of the induction loop 11 and on the other hand on the front flank of the bypass line 15 over the circumference of the inductor which is occupied by the bypass line 15. It can be seen that the water jets 20 also extend along the connecting tube 17.
  • the heated cross-sectional zone 4 of the tube 1 is instead formed S-shaped by moving it from the Bypass line 15, the associated connecting pipes 17 and the peripheral portion of the induction loop 11 to which the bypass line 15 together with the connecting pipes 17 is not parallel.
  • the first row of water jet nozzles 18 also extends in an S-shaped manner over all three elements of the inductor 3 mentioned.
  • the axial sequence of the further rows of water jet nozzles 19 and 20 is then as in the case of FIG. 4, but on other elements of the inductor arranged.
  • the water jet nozzles 19 are here on the bypass line 15 and the water jet nozzles 20 on the area the induction loop 15, which runs parallel to the bypass line 15.
  • the water jet nozzles 19 and 20 render part or all of the inductive heating of the tube 1 ineffective, specifically on the peripheral area which is described by the bypass line 15.
  • the transition between the different heating zones on the circumference of the tube can be set as desired by appropriate inclination of the connecting tubes 17 and corresponding arrangement of the water jet nozzles 19 and 20. It can be seen that in the embodiments of FIGS. 4 and 5 the heating on the intrados 9 is large and that on the extrados 10 is small, since the full induction heat acts on the extrados in the heating zone, while it is weakened in the area of the extrados.
  • the individual line sections formed by it in the inductor 3 can be adapted by selecting different cross sections of the inductor tube 12 and, if appropriate, its wall thickness so that the current branching in the individual line sections strictly according to Kirchhoff's law Law, or alternatively in a desired different manner.
  • the metal cross section of the bypass line 15 and the branched line section of the induction loop 11 can be chosen to be the same or different.
  • An auxiliary element is further explained on the arrangement according to FIG. 4, which can also be provided in the arrangement according to FIG. 5.
  • It is a blower tube 21 connected upstream of the inductor 3 in the feed direction of the tube 1, with air jet nozzles which, in accordance with the flow arrow 22 directed obliquely inwards and forwards, generate an air flow in the direction of the tube 1 pushed through the inductor 3. This ensures that the cooling water emerging from the water jet nozzles 18, 19 and 20 cannot strike back into the narrow cross-sectional zone 4 to be heated on the pipe.
  • the strength and direction of the blower radiation must be coordinated with the strength and direction of the cooling water radiation from the cooling water nozzles 18 to 20 mentioned.
  • cooling elements can be provided, which are ring-shaped separately from the inductor 3, for example in the manner of the annular blower tube 21 can be arranged around the tube 1 at a suitable location and in a suitable design.
  • this is more complex than the combined design of the inductor explained with reference to FIGS. 4 and 5 at the same time as a cooling element, it offers the advantage of greater variability in the application of the coolant. It is particularly easy to design individual nozzles or groups of nozzles to be adjustable in terms of the amount of coolant and preferably also in the direction of the coolant, and sometimes to use desired flat jet nozzles.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)
EP85109332A 1984-07-26 1985-07-25 Procédé et dispositif pour plier des objets longs, en particulier des tubes Withdrawn EP0169564A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19843427639 DE3427639A1 (de) 1984-07-26 1984-07-26 Verfahren und vorrichtung zum biegen laenglicher werkstuecke, insbesondere rohre
DE3427639 1984-07-26

Publications (2)

Publication Number Publication Date
EP0169564A2 true EP0169564A2 (fr) 1986-01-29
EP0169564A3 EP0169564A3 (fr) 1987-05-13

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EP85109332A Withdrawn EP0169564A3 (fr) 1984-07-26 1985-07-25 Procédé et dispositif pour plier des objets longs, en particulier des tubes

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US (1) US4596128A (fr)
EP (1) EP0169564A3 (fr)
DE (1) DE3427639A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109909335A (zh) * 2019-03-15 2019-06-21 株洲汉和工业设备有限公司 一种立式数控感应加热弯管机

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JP3400767B2 (ja) * 2000-02-28 2003-04-28 徹 佐藤 鋼管曲げ加工装置及び方法
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JPWO2010055747A1 (ja) * 2008-11-12 2012-04-12 住友金属工業株式会社 アーム素材およびその製造方法
DE102009060743B4 (de) * 2009-12-30 2011-11-24 Nova Bausysteme Gmbh Verfahren und Vorrichtung zum Herstellen von Wendeln aus Drähten
KR101414346B1 (ko) * 2010-01-06 2014-07-02 신닛테츠스미킨 카부시키카이샤 굴곡 부재의 제조 방법 및 제조 장치
EA024314B1 (ru) * 2010-01-06 2016-09-30 Сумитомо Метал Индастриз, Лтд. Катушка для индукционного нагрева, устройство и способ изготовления обработанной детали
US8511123B2 (en) * 2010-05-10 2013-08-20 Crc-Evans Pipeline International, Inc. Wedge driven pipe bending machine
DE102010020360B4 (de) * 2010-05-13 2016-06-16 AWS Schäfer Technologie GmbH Biegemaschine für linke und rechte Biegungen
WO2016056517A1 (fr) * 2014-10-07 2016-04-14 新日鐵住金株式会社 Appareil et procédé de refroidissement pour matériau en acier
US10427351B2 (en) 2016-02-19 2019-10-01 General Electric Company Apparatus for induction heating and bending of thermoplastic composite tubes and a method for using same
US11414723B2 (en) * 2018-05-21 2022-08-16 Welspun Corp Limited Systems and methods for producing hot induction pipe bends with homogeneous metallurgical and mechanical properties
CN116786650B (zh) * 2023-08-29 2023-10-24 河北恒通管件集团有限公司 一种煨制弯管装置及方法

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Publication number Priority date Publication date Assignee Title
CN109909335A (zh) * 2019-03-15 2019-06-21 株洲汉和工业设备有限公司 一种立式数控感应加热弯管机
CN109909335B (zh) * 2019-03-15 2024-01-23 株洲汉和工业设备有限公司 一种立式数控感应加热弯管机

Also Published As

Publication number Publication date
DE3427639A1 (de) 1986-02-06
DE3427639C2 (fr) 1988-04-14
US4596128A (en) 1986-06-24
EP0169564A3 (fr) 1987-05-13

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