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EP0268735B1 - Method for the folded or flanged connection of part of a tube to a connecting piece - Google Patents

Method for the folded or flanged connection of part of a tube to a connecting piece Download PDF

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Publication number
EP0268735B1
EP0268735B1 EP19870109167 EP87109167A EP0268735B1 EP 0268735 B1 EP0268735 B1 EP 0268735B1 EP 19870109167 EP19870109167 EP 19870109167 EP 87109167 A EP87109167 A EP 87109167A EP 0268735 B1 EP0268735 B1 EP 0268735B1
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EP
European Patent Office
Prior art keywords
area
carried out
internal stresses
folds
fold
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.)
Expired - Lifetime
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EP19870109167
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German (de)
French (fr)
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EP0268735A1 (en
Inventor
Rainer Hess
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LACO SA
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LACO SA
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
    • 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
    • B21D39/00—Application of procedures in order to connect objects or parts, e.g. coating with sheet metal otherwise than by plating; Tube expanders
    • B21D39/06—Application of procedures in order to connect objects or parts, e.g. coating with sheet metal otherwise than by plating; Tube expanders of tubes in openings, e.g. rolling-in

Definitions

  • the invention described here relates to a method for the folded or flanged connection of a pipe part to a connecting part or the like according to the preamble of claim 1 (DE-A-2 323 951).
  • the object of the invention described here is to design and develop the known processes, in particular the process known from DE-A-36 17 760.1, in such a way that such a folded or flanged connection can be carried out as easily as possible in terms of the device without losing a desired determinability, for example with regard to the fold which is initially formed and with regard to the size of the respective fold.
  • an area, a "web" remains between the two fold areas, the properties of which differ from those of the areas in which the folds are supposed to form, which essentially corresponds in its properties to the larger area spanning the fold area, the properties in this area being determined by the internal stresses generated.
  • the necessary generation of the residual stresses can be carried out in very different ways.
  • a corresponding warming-up of the tube part is possible in the area overlapping the fold area with subsequent quenching.
  • the temperatures known for the respective materials are to be set, which lead to the corresponding structural reorganization, which cannot be completely reversed when quenched, as a result of which compressive or tensile stresses (in the non-heat-treated area) then occur in the tube wall.
  • the generation of the residual stresses is achieved in that the tubular part is expanded in the area overlapping the fold area and in that a stress relief annealing is carried out in the respective areas in which the folds are to be formed.
  • a hydraulic expansion as well as a mechanical expansion is possible, reference is made in particular to the description in the patent application P 36 04 994.8.
  • the stress relief annealing in the respective areas in which the folds are to be formed is carried out differently such that residual stresses remain at least in one area (in which a fold is to be formed). In this way it can be determined which area initially poses a fold during the connection process, reference being made in particular to the disclosure of patent application DE-A-36 17 760.1 with regard to the advantages associated therewith.
  • the stress relief annealing can be carried out in the context of the invention, for example, by rotating the tube part in front of a fixed heat source. It is advisable to choose the heat source and in particular the heat generated on the outer tube wall so that a geometrically precisely defined heat is achieved, which means that a (partial) stress relief annealing can be reliably set precisely in the areas in which the folds are to be formed . Accordingly, it is also essential that defined temperatures are generated in these areas on the pipe part, in order in the individual areas to be able to achieve different stress relief anneals.
  • the stress relief annealing can be carried out by means of a conventional gas burner known from a welding device.
  • the stress relief annealing can also be effected by inductive heating.
  • the procedure was such that the residual stresses were first reduced in a first report, in which a fold is to be formed, and then initially waited until this area was practically completely cooled again, and only then in the second area in which a fold was to be formed, the residual stresses were reduced.
  • This procedure ensures that practically the residual stresses that were originally applied remain in the remaining "web” with certainty.
  • a simultaneous procedure can be achieved in that shielding is carried out with respect to the remaining “web” or even corresponding cooling elements are assigned to this area.
  • the shielding can take place, for example, by means of a copper ring.
  • the drawing shows a pipe section 1, which for example could also be a curved pipe section (cf. DE-A-36 04 944.1), in a cross-sectional view, into which a mandrel 2 is inserted.
  • the mandrel 2 has an area of larger diameter 3 and an area of smaller diameter 4.
  • the transition area 5 of the mandrel 2, between the area 3 and the area 4 is designed like a shoulder and lies against a corresponding shoulder area 6 of the pipe section 1.
  • This shoulder region 6 results in a counter-holder for the printing tool 7.
  • the printing tool 7 can, for example, which is not shown in the drawing, be designed to be divided.
  • a telescopic sleeve can also be provided, for example, as described in detail in patent application P 36 17 760.1.
  • the sleeve-like tool and the pressure tool for the counter-holder are designed in a combined manner on the shoulder area 6, while a sleeve-like tool 8 and a tool 9 are each provided in a manner known per se at the front end area of the tube piece 1 .
  • the same training could of course also be chosen in the area of the counter bracket.
  • the pipe section 1 shown has, due to the expansion by means of the mandrel 2 in the area 10, not inconsiderable residual stresses. These residual stresses are reduced in the annular regions a and c, the reduction of the residual stresses in the region c being carried out to an increased extent, the region c also being chosen to be larger than the region a, so that the fold in the region c is first with a somewhat larger extent, which is described in detail in terms of its usefulness etc. in patent application P 36 17 760.1.
  • the area b remains as a “web” between the areas a and c and furthermore has the same or substantially the same residual stresses as the remaining areas of the expanded pipe part 10.
  • the method according to the invention not only makes the device described in patent application P 36 17 760.1 unnecessary, as described in detail, but, as already mentioned, there is also a much more elastic connection between the pipe part and the connecting part and less force is required for the rebate , ie less power required.
  • the countermeasure was that region a was first annealed without stress, then this region was allowed to cool until it was practically cooled again.
  • the area c was then annealed without stress, in each case to the extent described above. Care was taken to ensure that only a slight warming occurred in area b, at most to the extent that only a blue discolouration occurred. If the entire area, a, b and c together, has a dimension of approximately 60 mm, then the first area a can have a dimension of approximately 20 mm, the area of 12 mm and the area c the remaining dimension.
  • these aforementioned dimensions are only examples and correspond to a test carried out in the workshop.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Shaping Of Tube Ends By Bending Or Straightening (AREA)
  • Heat Treatment Of Articles (AREA)

Description

Die hier beschriebene Erfindung betrifft ein Verfahren zur gefalzten oder gebördelten Verbindung eines Rohrteiles mit einem Verbindungsteil oder dergleichen nach dem Oberbegriff des Anspruchs 1 (DE-A-2 323 951).The invention described here relates to a method for the folded or flanged connection of a pipe part to a connecting part or the like according to the preamble of claim 1 (DE-A-2 323 951).

Zur gefalzten bzw. gebördelten Verbindung eines Rohrteils mit einem Verbindungsteil sind bereits verschiedene Verfahren bekannt geworden, insbesondere im Zusammenhang mit der Herstellung von Auspuffelementen (vgl. beispielsweise die gattungsbildende DE-A-23 23 951, das DE-U-73 36 778 und die nachveröffentlichten DE-A-36 04 921.2 und DE-A-36 17 760). Besondere Vorschläge sind hierbei bezüglich Ausbildung gefalzter Verbindungen bei gekrümmten Rohrteilen (nachveröffentlichte DE-A-36 04 994.8) und zur größen- und zeitpunktmäßig gesteuerten Ausbildung des einen und des anderen Falzes (DE-A-36 17 760.1) gemacht worden.Various are already available for the crimped or flanged connection of a pipe part to a connecting part Process become known, especially in connection with the production of exhaust elements (see, for example, the generic DE-A-23 23 951, DE-U-73 36 778 and the subsequently published DE-A-36 04 921.2 and DE-A-36 17 760). Special suggestions have been made regarding the formation of folded connections in the case of curved pipe parts (post-published DE-A-36 04 994.8) and for the size and timing of the formation of one and the other fold (DE-A-36 17 760.1).

Wenn auch insbesondere das letztgenannte Verfahren sich in der Praxis gut bewährt hat, so ist es doch noch mit gewissen Unzulänglichkeiten verbunden. Insbesondere ist eine aufwendige Vorrichtung erforderlich, um die zeitlich und größenmäßig gewünschte Ausbildung der einzelnen Falze zu erreichen.Even if the latter method in particular has proven itself well in practice, it is still associated with certain shortcomings. In particular, a complex device is required to achieve the desired formation of the individual folds in terms of time and size.

Im Hinblick auf den vorerwähnten Stand der Technik stellt sich der hier beschriebenen Erfindung die Aufgabe, die bekannten Verfahren, insbesondere das aus der DE-A-36 17 760.1 bekannte Verfahren so auszugestalten und weiterzubilden daß eine derartige gefalzte oder gebördelte Verbindung vorrichtungsmäßig möglichst einfach durchzuführen ist, ohne daß eine gewünschte Bestimmbarkeit etwa hinsichtlich des sich zunächst ausbildenden Falzes und hinsichtlich der Größe des jeweiligen Falzes verloren geht.In view of the above-mentioned prior art, the object of the invention described here is to design and develop the known processes, in particular the process known from DE-A-36 17 760.1, in such a way that such a folded or flanged connection can be carried out as easily as possible in terms of the device without losing a desired determinability, for example with regard to the fold which is initially formed and with regard to the size of the respective fold.

Diese Aufgabe ist gemäß der Erfindung mit einem Verfahren nach Anspruch 1 gelöst.This object is achieved according to the invention with a method according to claim 1.

Vorteilhafte Ausgestaltungen des Erfindungsgedankens sind Gegenstand der Unteransprüche.Advantageous embodiments of the inventive concept are the subject of the dependent claims.

Erfindungsgemäß ist erkannt worden, daß allein durch eine Erzeugung von Eigenspannungen und eine gezielte Veränderung dieser Eigenschaften in bestimmten Bereichen dem Rohrteil Eigenschaften aufgegeben werden können, die eine Ausbildung der Falze in bestimmten Bereichen ohne weiteres, d.h. ohne besondere zusätzliche Maßnahmen möglich macht.According to the invention, it has been recognized that solely by generating residual stresses and deliberately changing these properties in certain areas, properties can be given to the tube part that easily form the folds in certain areas, i.e. without special additional measures.

Wesentlich ist, daß, wie sich aus der zuvor gegebenen Lehre insbesondere im Zusammenhang gesehen mit den weiter oben erwähnten, bereits bekannten Verfahren ergibt, zwischen den beiden Falzbereichen ein Bereich, ein "Steg", verbleibt, dessen Eigenschaften sich von denjenigen der Bereiche, in denen die Falze sich ausbilden sollen, unterscheidet, der also im wesentlichen in seinen Eigenschaften dem größeren, den Falzbereich übergreifenden Bereich entspricht, wobei die Eigenschaften in diesem Bereich durch die erzeugten Eigenspannungen bestimmt sind.It is essential that, as can be seen from the teaching given above, particularly in connection with the already known methods mentioned above, an area, a "web", remains between the two fold areas, the properties of which differ from those of the areas in which the folds are supposed to form, which essentially corresponds in its properties to the larger area spanning the fold area, the properties in this area being determined by the internal stresses generated.

In Ausgestaltung des Verfahrens kann die notwendige Erzeugung der Eigenspannungen auf sehr verschiedene Weisen vorgenommen werden. Beispielsweise ist zunächst eine entsprechende Aufwärmung des Rohrteiles in dem den Falzbereich übergreifenden Bereich mit einer nachfolgenden Abschreckung möglich. Hierbei sind dann die für die jeweiligen Werkstoffe bekannten Temperaturen einzustellen, die zur entsprechenden Gefügeumbildung, die beim Abschrecken nicht vollständig rückgängig gemacht werden kann, führen, wodurch sich dann in der Rohrwand Druck- bzw. Zugspannungen (in dem nicht wärmebehandelten Bereich) einstellen.In one embodiment of the method, the necessary generation of the residual stresses can be carried out in very different ways. For example, a corresponding warming-up of the tube part is possible in the area overlapping the fold area with subsequent quenching. In this case, the temperatures known for the respective materials are to be set, which lead to the corresponding structural reorganization, which cannot be completely reversed when quenched, as a result of which compressive or tensile stresses (in the non-heat-treated area) then occur in the tube wall.

Darüber hinaus, und im Rahmen der vorliegenden Erfindung bevorzugt ist es aber auch möglich, daß die Erzeugung der Eigenspannungen dadurch erreicht wird, daß das Rohrteil in dem den Falzbereich übergreifenden Bereich aufgeweitet wird und daß in den jeweiligen Bereichen, in denen die Falze sich ausbilden sollen, eine Spannungsfreiglühung vorgenommen wird. Bezüglich des Aufweitens, wozu sich ein hydraulisches Aufweiten wie auch ein mechanisches Aufweiten anbietet, wird insbesondere auch auf die Beschreibung in der Patentanmeldung P 36 04 994.8 Bezug genommen.In addition, and preferably within the scope of the present invention, it is also possible that the generation of the residual stresses is achieved in that the tubular part is expanded in the area overlapping the fold area and in that a stress relief annealing is carried out in the respective areas in which the folds are to be formed. With regard to the expansion, for which a hydraulic expansion as well as a mechanical expansion is possible, reference is made in particular to the description in the patent application P 36 04 994.8.

In weiterer Ausgestaltung des Verfahrens ist bevorzugt vorgesehen, daß die Spannungsfreiglühung in den jeweiligen Bereichen, in denen die Falze sich ausbilden sollen, unterschiedlich so durchgeführt wird, daß zumindest in einem Bereich (in dem sich ein Falz ausbilden soll) Restspannungen verbleiben. Hierdurch kann bestimmt werden, welcher Bereich sich bei dem Verbindungsvorgang zunächst zu einem Falz aufwirft, wobei bezüglich der hiermit verbundenen Vorteile etc. insbesondere auf die Offenbarung der Patentanmeldung DE-A-36 17 760.1 verwiesen wird.In a further embodiment of the method, it is preferably provided that the stress relief annealing in the respective areas in which the folds are to be formed is carried out differently such that residual stresses remain at least in one area (in which a fold is to be formed). In this way it can be determined which area initially poses a fold during the connection process, reference being made in particular to the disclosure of patent application DE-A-36 17 760.1 with regard to the advantages associated therewith.

Die Spannungsfreiglühung kann im Rahmen der Erfindung beispielsweise dadurch vorgenommen werden, daß das Rohrteil vor einer feststehenden Wärmequelle rotiert. Es empfiehlt sich, die Wärmequelle und insbesondere die dadurch erzeugte Wärmeeinwirkung auf der Rohraußenwand so zu wählen, daß eine geometrisch genau abgegrenzte Wärmeeinwirkung erreicht wird, wodurch sich zuverlässig genau in den Bereichen eine (teilweise) Spannungsfreiglühung einstellen läßt, in denen die Falze sich ausbilden sollen. Entsprechend ist es auch wesentlich, daß definierte Temperaturen in diesen Bereichen auf dem Rohrteil erzeugt werden, um in den einzelnen Bereichen unterschiedliche Spannungsfreiglühungen erreichen zu können. Beispielsweise kann die Spannungsfreiglühung mittels eines gewöhnlichen, von einer Schweißvorrichtung her bekannten, Gasbrenners vorgenommen werden.The stress relief annealing can be carried out in the context of the invention, for example, by rotating the tube part in front of a fixed heat source. It is advisable to choose the heat source and in particular the heat generated on the outer tube wall so that a geometrically precisely defined heat is achieved, which means that a (partial) stress relief annealing can be reliably set precisely in the areas in which the folds are to be formed . Accordingly, it is also essential that defined temperatures are generated in these areas on the pipe part, in order in the individual areas to be able to achieve different stress relief anneals. For example, the stress relief annealing can be carried out by means of a conventional gas burner known from a welding device.

Natürlich kann die Spannungsfreiglühung auch durch induktive Erhitzung bewirkt werden.Of course, the stress relief annealing can also be effected by inductive heating.

Bei einer praktischen Durchführung des Verfahrens, bislang ohne eigens hierfür konstruierte Vorrichtungen, sondern lediglich mit werkstattmäßig vorhandenen Mitteln, ist so vorgegangen worden, daß zunächst in einem ersten Bericht, in dem ein Falz sich ausbilden soll, die Eigenspannungen vermindert worden sind, sodann zunächst zugewartet wurde, bis dieser Bereich praktisch vollkommen wieder abgekühlt war, und dann erst in dem zweiten Bereich, in dem ein Falz sich ausbilden sollte, die Eigenspannungen vermindert worden sind. Dieses Vorgehen stellt sicher, daß in dem verbleibenden "Steg" mit Sicherheit praktisch die Eigenspannungen verbleiben, die ursprünglich aufgebracht worden sind. Eine Gleichzeitigkeit des Vorgehens kann dem gegenüber dadurch erreicht werden, daß bezüglich des verbleibenden "Stegs" eine Abschirmung vorgenommen wird, oder sogar entsprechende Kühlelemente diesem Bereich zugeordnet werden. Die Abschirmung kann beispielsweise mittels eines Kupferrings erfolgen.In a practical implementation of the method, so far without devices specially designed for this purpose, but only with means available in the workshop, the procedure was such that the residual stresses were first reduced in a first report, in which a fold is to be formed, and then initially waited until this area was practically completely cooled again, and only then in the second area in which a fold was to be formed, the residual stresses were reduced. This procedure ensures that practically the residual stresses that were originally applied remain in the remaining "web" with certainty. In contrast, a simultaneous procedure can be achieved in that shielding is carried out with respect to the remaining “web” or even corresponding cooling elements are assigned to this area. The shielding can take place, for example, by means of a copper ring.

Insgesamt lassen sich mit dem erfindungsgemäßen Verfahren, auch schon gemäß seiner weiter oben beschriebenen grundsätzlichen Ausgestaltung, elastischere Falz- bzw. Bördelverbindungen erreichen. Darüber hinaus ist auch zur Falzausbildung weniger Kraft, d.h. weniger Leistung erforderlich.Overall, with the method according to the invention, even according to its basic configuration described above, more elastic fold or flare connections can be achieved. In addition, less force is required to form the fold, i.e. less power required.

Nachstehend wird die Erfindung noch anhand der beigefügten, jedoch lediglich ein Ausführungsbeispiel darstellenden, Zeichnung näher erläutert. Die einzige Figur der Zeichnung zeigt ein mittels eines Dornes aufgeweitetes Rohrteil, welches in bestimmten Bereichen spannungsfrei geglüht ist.The invention is explained in more detail below with reference to the attached drawing, which, however, only represents an exemplary embodiment. The only figure in the drawing shows a tube part which has been expanded by means of a mandrel and which is annealed in certain areas without stress.

In einzelnen zeigt die Zeichnung ein Rohrstück 1, welches beispielsweise auch ein gekrümmtes Rohrstück sein könnte (vgl. DE-A-36 04 944.1), in Querschnittsdarstellung, in welches ei Dorn 2 eingeführt ist. Der Dorn 2 besitzt einen Bereich größeren Durchmessers 3 und einen Bereich kleineren Durchmessers 4. Der Übergangsbereich 5 des Dornes 2, zwischen dem Bereich 3 und dem Bereich 4, ist schulterartig ausgebildet und liegt an einem entsprechenden Schulterbereich 6 des Rohrstückes 1 an. Dieser Schulterbereich 6 ergibt eine Gegenhalterung für das Druckwerkzeug 7. Das Druckwerkzeug 7 kann beispielsweise, was auf der Zeichnung nicht zu erkennen ist, geteilt ausgeführt sein. Auch kann beispielsweise eine Teleskophülse vorgesehen sein, wie sie im einzelnen in der Patentanmeldung P 36 17 760.1 beschrieben ist.In detail, the drawing shows a pipe section 1, which for example could also be a curved pipe section (cf. DE-A-36 04 944.1), in a cross-sectional view, into which a mandrel 2 is inserted. The mandrel 2 has an area of larger diameter 3 and an area of smaller diameter 4. The transition area 5 of the mandrel 2, between the area 3 and the area 4, is designed like a shoulder and lies against a corresponding shoulder area 6 of the pipe section 1. This shoulder region 6 results in a counter-holder for the printing tool 7. The printing tool 7 can, for example, which is not shown in the drawing, be designed to be divided. A telescopic sleeve can also be provided, for example, as described in detail in patent application P 36 17 760.1.

Wie zu erkennen ist, ist bei dem dargestellten Ausführungsbeispiel das muffenartige Werkzeug und das Druckwerkzeug für die Gegenhalterung an dem Schulterbereich 6 kombiniert ausgebildet, während an dem vorderen Endbereich des Rohrstückes 1 in an sich bekannter Weise je ein muffenartiges Werkzeug 8 und ein Werkzeug 9 vorgesehen sind. Gleiche Ausbildung könnte natürlich auch im Bereich der Gegenhalterung gewählt sein.As can be seen, in the exemplary embodiment shown, the sleeve-like tool and the pressure tool for the counter-holder are designed in a combined manner on the shoulder area 6, while a sleeve-like tool 8 and a tool 9 are each provided in a manner known per se at the front end area of the tube piece 1 . The same training could of course also be chosen in the area of the counter bracket.

Das dargestellte Rohrstück 1 weist durch die Aufweitung mittels des Dornes 2 in dem Bereich 10 nicht unbeträchtliche Eigenspannungen auf. Diese Eigenspannungen sind in den kreisringförmigen Bereichen a und c vermindert, wobei die Verminderung der Eigenspannungen in dem Bereich c in erhöhtem Maße durchgeführt worden ist, wobei der Bereich c auch größer gewählt ist als der Bereich a, damit sich der Falz in dem Bereich c zuerst mit einem etwas größeren Ausmaß ausbildet, was hinsichtlich seiner Zweckmäßigkeit usw. im einzelnen in der Patentanmeldung P 36 17 760.1 beschrieben ist.The pipe section 1 shown has, due to the expansion by means of the mandrel 2 in the area 10, not inconsiderable residual stresses. These residual stresses are reduced in the annular regions a and c, the reduction of the residual stresses in the region c being carried out to an increased extent, the region c also being chosen to be larger than the region a, so that the fold in the region c is first with a somewhat larger extent, which is described in detail in terms of its usefulness etc. in patent application P 36 17 760.1.

Der Bereich b verbleibt als "Steg" zwischen den Bereichen a und c und weist weiterhin die gleichen oder im wesentlichen die gleichen Eigenspannungen auf wie die verbleibenden Bereiche des aufgeweiteten Rohrteiles 10.The area b remains as a “web” between the areas a and c and furthermore has the same or substantially the same residual stresses as the remaining areas of the expanded pipe part 10.

Durch das erfindungsgemäße Verfahren wird nicht nur wie im einzelnen beschrieben die in der Patentanmeldung P 36 17 760.1 beschriebene Vorrichtung unnötig, sondern, wie auch bereits erwähnt, stellt sich auch eine wesentlich elastischere Verbindung zwischen dem Rohrteil und dem Verbindungsteil ein und ist zur Auffalzung weniger Kraft, d.h. weniger Leistung erforderlich.The method according to the invention not only makes the device described in patent application P 36 17 760.1 unnecessary, as described in detail, but, as already mentioned, there is also a much more elastic connection between the pipe part and the connecting part and less force is required for the rebate , ie less power required.

Bei einer praktischen Durchführung des Verfahrens wurde so vorgegen-gen, daß zunächst der Bereich a Spannungsfrei geglüht wurde, dann dieser Bereich so lange abkühlen gelassen wurde, bis er praktisch wieder erkaltet war. Sodann wurde der Bereich c Spannungsfrei geglüht, jeweils in dem Ausmaß, wie zuvor schon beschrieben. Es wurde darauf geachtet, daß in dem Bereich b nur eine geringe Erwärmung auftrat, allenfalls soweit, daß lediglich eine Blauverfärbung eintrat. Wenn der gesamte Bereich, a, b und c zusammen, etwa ein Ausmaß von 60 mm hat, so kann der erste Bereich a etwa eine Abmessung von 20 mm aufweisen, den Bereich von 12 mm und der Bereich c das verbleibende Maß. Diese vorgenannten Maße sind jedoch lediglich beispielhaft und entsprechen einem werkstattmäßig durchgeführten Versuch.When the process was carried out in practice, the countermeasure was that region a was first annealed without stress, then this region was allowed to cool until it was practically cooled again. The area c was then annealed without stress, in each case to the extent described above. Care was taken to ensure that only a slight warming occurred in area b, at most to the extent that only a blue discolouration occurred. If the entire area, a, b and c together, has a dimension of approximately 60 mm, then the first area a can have a dimension of approximately 20 mm, the area of 12 mm and the area c the remaining dimension. However, these aforementioned dimensions are only examples and correspond to a test carried out in the workshop.

Die in der vorstehenden Beschreibung, den Ansprüchen und der Zeichnung offenbarten Merkmale der Erfindung können sowohl einzeln als auch in beliebiger Kombination für die Verwirklichung der Erfindung in ihren verschiedenen Ausgestaltungen von Bedeutung sein.The features of the invention disclosed in the above description, the claims and the drawing can be of importance both individually and in any combination for realizing the invention in its various configurations.

Claims (5)

  1. A method for the folded or flanged connection of part of a metal tube (1) to a connecting member or the like, which has a foot zone which substantially encloses the tubular part (1) and co-operates therewith, folds which co-operate with the foot zone on both sides of the connecting member being formed by axial impacting and radial guidance in the tujbular member (1) , characterised in that the following steps are carried out successively before the axial impacting:
    - internal stresses are produced in the tubular part (1) only in those zones (a, c) in which the folds are to be formed, and the zone (b) therebetween, and
    - at least partial reduction of the internal stresses by annealing in those zones (a, c) in which the folds are to be formed.
  2. A method according to claim 1 characterised in that the internal stresses are produced by expanding.
  3. A method according to claim 1, characterised in that the internal stresses are produced by heating followed by quenching.
  4. A method according to any one of the preceding claims, characterised in that the reduction of the internal stresses is carried out with different intensities in the different fold zones (a, c), residual stresses remaining in at least one of the fold zones.
  5. A method according to any one of the preceding claims, characterised in that the annealing is carried out by rotating the tubular part in front of a stationary heat source.
EP19870109167 1986-10-31 1987-06-26 Method for the folded or flanged connection of part of a tube to a connecting piece Expired - Lifetime EP0268735B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19863637137 DE3637137A1 (en) 1986-10-31 1986-10-31 METHOD FOR FOLDING OR BALANCED CONNECTING A PIPE PART TO A CONNECTING PART
DE3637137 1986-10-31

Publications (2)

Publication Number Publication Date
EP0268735A1 EP0268735A1 (en) 1988-06-01
EP0268735B1 true EP0268735B1 (en) 1991-08-21

Family

ID=6312901

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19870109167 Expired - Lifetime EP0268735B1 (en) 1986-10-31 1987-06-26 Method for the folded or flanged connection of part of a tube to a connecting piece

Country Status (2)

Country Link
EP (1) EP0268735B1 (en)
DE (2) DE3637137A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102017121180B4 (en) 2016-09-16 2019-07-25 GM Global Technology Operations LLC Method of reducing residual stress in molded bushings of HPDC engine blocks

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02134338U (en) * 1989-04-13 1990-11-07

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3728886A (en) * 1971-03-24 1973-04-24 Emerson Electric Co Method of producing precision tapered tubes
US3921754A (en) * 1973-03-29 1975-11-25 Rainer Hess Muffler having a connection between its disks and the tube lengths extending therethrough
US4130932A (en) * 1975-11-11 1978-12-26 Arkla Industries, Inc. Method of joining a tube to a plate

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102017121180B4 (en) 2016-09-16 2019-07-25 GM Global Technology Operations LLC Method of reducing residual stress in molded bushings of HPDC engine blocks

Also Published As

Publication number Publication date
DE3637137A1 (en) 1988-05-05
EP0268735A1 (en) 1988-06-01
DE3772334D1 (en) 1991-09-26

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