EP0141350A1 - Method of preparing work pieces from metal powder - Google Patents

Method of preparing work pieces from metal powder Download PDF

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Publication number
EP0141350A1
EP0141350A1 EP84112605A EP84112605A EP0141350A1 EP 0141350 A1 EP0141350 A1 EP 0141350A1 EP 84112605 A EP84112605 A EP 84112605A EP 84112605 A EP84112605 A EP 84112605A EP 0141350 A1 EP0141350 A1 EP 0141350A1
Authority
EP
European Patent Office
Prior art keywords
capsule
elastically stretchable
weld seam
jacket surface
jacket
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.)
Granted
Application number
EP84112605A
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German (de)
French (fr)
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EP0141350B1 (en
Inventor
Christer Aslund
Claes Tornberg
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.)
Nyby Uddeholm Powder AB
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Nyby Uddeholm Powder AB
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Publication of EP0141350A1 publication Critical patent/EP0141350A1/en
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Publication of EP0141350B1 publication Critical patent/EP0141350B1/en
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02—Compacting only
    • B22F3/04—Compacting only by applying fluid pressure, e.g. by cold isostatic pressing [CIP]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/02—Compacting only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/1208—Containers or coating used therefor
    • B22F3/1216—Container composition
    • B22F3/1233—Organic material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • B22F3/1208—Containers or coating used therefor
    • B22F3/1216—Container composition
    • B22F3/1241—Container composition layered
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S29/00—Metal working
    • Y10S29/031—Pressing powder with other step
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
    • Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
    • Y10T428/1355—Elemental metal containing [e.g., substrate, foil, film, coating, etc.]
    • Y10T428/1359—Three or more layers [continuous layer]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913—Rod, strand, filament or fiber
    • Y10T428/2973—Particular cross section
    • Y10T428/2975—Tubular or cellular

Definitions

  • the invention relates to a method for producing powder metallurgical objects according to the preamble of claim 1 and the application of the method for producing elongated objects, in particular pipes.
  • the metal powder into thin-walled capsules, the shape of which corresponds to the shape of the objects to be produced, for the production of powder-metallurgical objects.
  • the capsules filled with metal powder are then closed and subjected to cold isostatic pressure, which causes the powder to compact, so that solid or dimensionally stable objects are produced.
  • At least the outer capsule shell has an approximately rectilinear connection weld, preferably extending approximately in the longitudinal direction of the capsule. This represents an extremely critical area.
  • a longitudinal fold extending into the interior of the capsule occurs when the cold isostatic pressure is applied, ie during cold isostatic pressing, along the weld seam in the immediate vicinity thereof. In such a case, the pellet must be rejected as a committee. The resulting losses in machine time and material are obvious.
  • the present invention is therefore based on the object of avoiding the creasing mentioned during isostatic pressing in the area of the weld seam.
  • the elastic layer can be glued to the outer surface of the capsule shell or can only be pulled or put over the outer surface of the capsule shell.
  • the elastically stretchable layer is fixed by means of hose clamps, adhesive strips in the area of the front ends of the capsule.
  • a particularly simple solution is to use a sleeve made of elastically stretchable material, which is approximately the same length as the capsule shell and has an inner diameter which is slightly less than the outer diameter of the capsule shell. This sleeve is pulled over the outer capsule shell before the cold isostatic pressure is applied. Due to the above-mentioned diameter ratios, a tight fit is guaranteed after mounting on the capsule shell. It is also ensured that the elastic layer formed in this way exerts an approximately uniform surface pressure on the lateral surface.
  • the front ends of the elastically stretchable and pressure-distributing layer are preferably designed to be somewhat thicker, in order in this way to compensate for the additional pressure on the capsule on the front side.
  • the tubular capsule 10 according to FIGS. 1 and 2 is filled with preferably spherical powder 13 made of metal and / or metal alloys and is closed on all sides.
  • the inner tubular jacket 11 is formed in one piece, while the outer tubular jacket 12 consists of a thin-walled sheet metal blank bent into a cylindrical sleeve, the abutting longitudinal edges of which are connected to one another by means of an approximately rectilinear weld seam 14 which extends in the longitudinal direction of the capsule.
  • the risk of wrinkles forming in the area of the weld seam 14 can certainly be avoided by surrounding the outer surface of the weld seam (outer tubular jacket 12) with an elastically stretchable layer 15, for example in the form of a sleeve made of elastically stretchable material, such as hard rubber, rubber, or the like (FIGS. 3 and 4) .
  • an elastically stretchable layer 15 for example in the form of a sleeve made of elastically stretchable material, such as hard rubber, rubber, or the like (FIGS. 3 and 4) .
  • the sleeve 15 made of elastically stretchable material and drawn over the outer jacket 12 has a greater thickness in the region of the front ends of the capsule 10 than in the region in between. This compensates for the pressurization of the capsule 10 on the face side.
  • the inner diameter of the elastic, stretchable sleeve 15 is somewhat smaller than the outer diameter of the capsule 10 or the outer capsule shell 12, so that it is ensured that the sleeve 15 lies tightly or closely against the outer shell 12 of the capsule 10 and there is a somewhat uniform prestressing thereon exercises.
  • the sleeve 15 made of elastically stretchable material causes an approximately uniform pressure distribution when a cold isostatic pressure is applied, as a result of which the aforementioned wrinkling in the region of the longitudinal weld seam 14 is avoided. This fold is identified in FIG. 2 by reference number 16.
  • the sleeve 15 made of elastically stretchable material is fixed in the embodiment according to FIGS. 3 and 4 in the region of the front ends of the capsule 10 by means of hose bands 17 of a conventional type.
  • the elastically stretchable layer is also relatively thin-walled.
  • the wall thickness corresponds approximately to the wall thickness of the capsule skin.
  • the wall thickness of the elastically stretchable layer 15 is preferably approximately twice as large as the wall thickness of the capsule skin 11 or 12.

Abstract

Verfahren zur Herstellung pulvermetallurgischer Gegenstände, bei dem Puler aus Metall und/oder Metalllegierungen in eine dünnwandige Kapsel eingefüllt, die Kapsel anschließend verschlossen und einem kaltisostatischen Druck ausgesetzt wird. Dadurch erfolgt eine Verdichtung des Pulvers innerhalb der Kapsel, so daß ein fester bzw. formbeständiger Gegenstand entsteht. Sofern der Kapselmantel eine Verbindungs- Schweißnaht aufweist, wird dieser zur Vermeidung einer Faltenbildung in unmittelbarer Nähe der Schweißnaht mit einer elastisch dehnbaren Schicht versehen, vorzugsweise derart, daß auf die Mantelfläche eine etwa gleichmäßige Vorspannung aufgebracht wird.Process for the production of powder metallurgical objects, in which powder made of metal and / or metal alloys is filled into a thin-walled capsule, the capsule is then sealed and subjected to cold isostatic pressure. As a result, the powder is compressed within the capsule, so that a solid or dimensionally stable object is produced. If the capsule casing has a connecting weld seam, this is provided with an elastically stretchable layer in order to avoid wrinkling in the immediate vicinity of the weld seam, preferably in such a way that an approximately uniform prestress is applied to the casing surface.

Description

Die Erfindung betrifft ein Verfahren zur Herstellung pulvermetallurgischer Gegenstände nach dem Oberbegriff des Patentanspruches 1 sowie die Anwendung des Verfahrens zur Herstellung von langgestreckten Gegenständen, insbesondere Rohren.The invention relates to a method for producing powder metallurgical objects according to the preamble of claim 1 and the application of the method for producing elongated objects, in particular pipes.

Es ist allgemein bekannt, zur Herstellung pulvermetallurgischer Gegenstände das Metallpulver in dünnwandige Kapseln einzufüllen, deren Form der Form der herzustellenden Gegenstände entspricht. Anschließend werden die mit Metallpulver gefüllten Kapseln verschlossen und einem kaltisostatischen Druck ausgesetzt, wodurch eine Verdichtung des Pulvers erfolgt, so daß feste bzw. formbeständige Gegenstände entstehen. Bei Gegenständen größeren Ausmaßes weist zumindest der äußere Kapselmantel eine etwa geradlinige, sich vorzugsweise etwa in Kapsellängsrichtung erstreckende Verbindungs-Schweißnaht auf. Diese stellt einen äußerst kritischen Bereich dar. Versuche haben gezeigt, daß längs der Schweißnaht in unmittelbarer Nähe derselben beim Aufbringen des kaltisostatischen Drucks, d.h. bei der kaltisostatischen Verpressung, eine sich in das Kapselinnere ausdehnende Längsfalte entsteht. Der Pressling muß in einem solchen Fall als Ausschuß ausgesondert werden. Die dadurch entstehenden Verluste an Maschinenzeit und Material sind augenscheinlich.It is generally known to fill the metal powder into thin-walled capsules, the shape of which corresponds to the shape of the objects to be produced, for the production of powder-metallurgical objects. The capsules filled with metal powder are then closed and subjected to cold isostatic pressure, which causes the powder to compact, so that solid or dimensionally stable objects are produced. For objects larger out At least the outer capsule shell has an approximately rectilinear connection weld, preferably extending approximately in the longitudinal direction of the capsule. This represents an extremely critical area. Experiments have shown that a longitudinal fold extending into the interior of the capsule occurs when the cold isostatic pressure is applied, ie during cold isostatic pressing, along the weld seam in the immediate vicinity thereof. In such a case, the pellet must be rejected as a committee. The resulting losses in machine time and material are obvious.

Der vorliegenden Erfindung liegt daher die Aufgabe zugrunde, die erwähnte Faltenbildung bei der isostatischen Verpressung im bereich der Schweißnaht zu vermeiden.The present invention is therefore based on the object of avoiding the creasing mentioned during isostatic pressing in the area of the weld seam.

Diese Aufgabe wird in überraschend einfacher Weise durch die kennzeichnenden Maßnahmen des Patentanspruches 1 gelöst.This object is achieved in a surprisingly simple manner by the characterizing measures of claim 1.

Bevorzugte Ausführungsformen der Erfindung sind in den Unteransprüchen beschrieben. Als besonders vorteilhaft hat sich das erfindungsgemäße Verfahren zur Herstellung von langgestreckten Gegenständen, insbesondere Rohren, deren Außenmantel eine oder mehrere sich in Rohrlängsrichtung erstreckende Schweißnähte aufweist, herausgestellt.Preferred embodiments of the invention are described in the subclaims. The method according to the invention for producing elongated objects, in particular pipes, whose outer jacket has one or more weld seams extending in the longitudinal direction of the pipe, has proven to be particularly advantageous.

Durch die erfindungsgemäße Maßnahme, die die Schweißnaht umfassende Mantelfläche mit einer elastisch dehnbaren Schicht aus Hartgummi oder ähnlichem Material zu versehen derart, daß diese Fläche mit einer etwa gleichmäßigen Vorspannung beaufschlagt wird, wird eine etwa gleichförmige Druckverteilung über den gesamten Umfang des Kapselmantels erzielt. Auf diese Weise wird überraschend eine Faltenbildung längs der Schweißnaht beim Aufbringen des kaltisostatischen Drucks sicher vermieden. Es ist natürlich wesentliche Voraussetzung für die Funktion der elastisch dehnbaren Schicht, daß diese dicht an der Außenfläche des Kapselmantels an-. liegt und vorzugsweise einen etwa gleichmäßigen Flächendruck ausübt.By the measure according to the invention, to provide the circumferential surface comprising the weld seam with an elastically stretchable layer of hard rubber or similar material in such a way that an approximately uniform prestress is applied to this surface, an approximately uniform pressure distribution is achieved over the entire circumference of the capsule shell. In this way, wrinkling along the weld seam is surprisingly certain when the cold isostatic pressure is applied avoided. It is, of course, an essential prerequisite for the function of the elastically stretchable layer that it fits closely to the outer surface of the capsule shell. lies and preferably exerts an approximately uniform surface pressure.

Die elastische Schicht kann auf die Außenfläche des Kapselmantels geklebt oder auch nur über die Außenfläche des Kapselmantels gezogen bzw. gestülpt werden. Die Fixierung der elastisch dehnbaren Schicht erfolgt mittels Schlauchschellen, Klebestreifen im Bereich der stirnseitigen Enden der Kapsel.The elastic layer can be glued to the outer surface of the capsule shell or can only be pulled or put over the outer surface of the capsule shell. The elastically stretchable layer is fixed by means of hose clamps, adhesive strips in the area of the front ends of the capsule.

Bei zylindrischem Kapselmantel stellt eine besonders einfache Lösung die Verwendung einer Hülse aus elastisch dehnbarem Material dar, die etwa dieselbe Länge wie der Kapselmantel und einen inneren Druchmesser aufweist, der etwas geringer ist als der Außendurchmesser des Kapselmantels. Diese Hülse wird vor Aufbringung des kaltisostaitschen Drucks über den äußeren Kapselmantel gezogen. Aufgrund der erwähnten Durchmesserverhältnisse ist ein dichtes Anliegen nach dem Aufziehen auf den Kapselmantel gewährleistet. Es ist ferner sichergestellt, daß die derart ausgebildete elastische Schicht auf die Mantelfläche einen etwa gleichmäßigen Flächendruck ausübt.In the case of a cylindrical capsule shell, a particularly simple solution is to use a sleeve made of elastically stretchable material, which is approximately the same length as the capsule shell and has an inner diameter which is slightly less than the outer diameter of the capsule shell. This sleeve is pulled over the outer capsule shell before the cold isostatic pressure is applied. Due to the above-mentioned diameter ratios, a tight fit is guaranteed after mounting on the capsule shell. It is also ensured that the elastic layer formed in this way exerts an approximately uniform surface pressure on the lateral surface.

Vorzugsweise sind die stirnseitigen Enden der elastisch dehnbaren und druckverteilenden Schicht etwas stärker ausgebildet, um auf diese Weise die zusätzliche stirnseitige Druckbeaufschlagung der Kapsel zu kompensieren.The front ends of the elastically stretchable and pressure-distributing layer are preferably designed to be somewhat thicker, in order in this way to compensate for the additional pressure on the capsule on the front side.

Nachstehend wird das erfindungsgemäße Verfahren anhand eines Ausführungsbeispieles, das in der anliegenden Zeichnung schematisch dargestellt ist, nochmals erläutert. Es zeigen:

  • Figur 1 eine rohrförmige und mit Metallpulver gefüllte Kapsel, die nach dem herkömmlichen Verfahren verpresst ist, im Längsschnitt,
  • Figur 2 die Kapsel nach Figur 1 im Querschnitt,
  • Figur 3 eine nach dem erfindungsgemäßen Verfahren verpresste Kapsel im Längsschnitt, und
  • Figur 4 die Kapsel nach Figur 3 im Querschnitt.
In the following, the method according to the invention is repeated using an exemplary embodiment which is shown schematically in the accompanying drawing purifies. Show it:
  • FIG. 1 shows a longitudinal section of a tubular capsule filled with metal powder, which is pressed by the conventional method,
  • FIG. 2 shows the capsule according to FIG. 1 in cross section,
  • 3 shows a capsule pressed according to the inventive method in longitudinal section, and
  • Figure 4 shows the capsule of Figure 3 in cross section.

Die rohrförmige Kapsel 10 nach den Figuren 1 und 2 ist mit vorzugsweise sphärischem Pulver 13 aus Metall und/ oder Metallegierungen gefüllt und allseitig geschlossen. Der innere Rohrmantel 11 ist einstückig ausgebildet, während der äußere Rohrmantel 12 aus einem zu einer zylindrischen Hülse gebogenen dünnwandigen Blechzuschnitt besteht, dessen aneinanderstoßende Längskanten mittels einer etwa geradlinigen, sich in Kapsellängsrichtung erstreckenden Schweißnaht 14 miteinander verbunden sind. Beim Aufbringen eines kaltisostatischen Drucks zum Zwecke der Verpressung des Metallpulvers innerhalb der Kapsel 10 zu einem insgesamt festen bzw. formbeständigen GEgenstand (Rohrabschnitt) besteht die Gefahr, daß sich in unmittelbarer Nähe der Verbindungs-Schweißnaht 14 eine sich in das Kapselinnere erstreckende Längsfalte bildet, die selbstverständlich unerwünscht ist. Der verpresste Gegenstand muß in einem solchen Fall als Ausschuß ausgesondert werden. Die Längsfalte entsteht offensichtlich durch eine Art Kerbwirkung der Schweißnaht 14.The tubular capsule 10 according to FIGS. 1 and 2 is filled with preferably spherical powder 13 made of metal and / or metal alloys and is closed on all sides. The inner tubular jacket 11 is formed in one piece, while the outer tubular jacket 12 consists of a thin-walled sheet metal blank bent into a cylindrical sleeve, the abutting longitudinal edges of which are connected to one another by means of an approximately rectilinear weld seam 14 which extends in the longitudinal direction of the capsule. When a cold isostatic pressure is applied for the purpose of pressing the metal powder inside the capsule 10 to form an overall solid or dimensionally stable object (pipe section), there is a risk that a longitudinal fold extending into the interior of the capsule will form in the immediate vicinity of the connecting weld seam, which is of course undesirable. In such a case, the pressed object must be discarded as a committee. The longitudinal fold obviously arises from a type of notch effect of the weld seam 14.

Überraschenderweise hat sich gezeigt, daß die Gefahr einer Faltenbildung im Bereich der Schweißnaht 14 sicher dadurch vermieden werden kann, daß die die Schweißnaht umfassende Mantelfläche (äußerer Rohrmantel 12) mit einer elastisch dehnbaren Schicht 15, z.B. in Form einer Hülse aus elastisch dehnbarem Material, wie Hartgummi, Kautschuk, oder dergleichen, umgeben wird (Figuren 3 und 4). Bei der Ausführungsform nach den Figuren 3 und 4 weist die über den Außenmantel 12 gezogene Hülse 15 aus elastisch dehnbarem Material im Bereich der stirnseitigen Enden der Kapsel 10 eine größere Dicke auf als im Bereich dazwischen. Dadurch wird eine Kompensierung der stirnseitigen Druckbeaufschlagung der Kapsel 10 erreicht. Der Innendurchmesser der elastischen dehnbaren Hülse 15 ist etwas geringer als der Außendurchmesser der Kapsel 10 bzw. des äußeren Kapselmantels 12, so daß sichergestellt ist, daß die Hülse 15 dicht bzw. eng am Außenmantel 12 der Kapsel 10 anliegt und auf diesen eine etwas gleichmäßige vorspannung ausübt. Die Hülse 15 aus elastisch dehnbarem Material bewirkt eine etwa gleichförmige Druckverteilung beim Aufbringen eines kaltisostatischen Drucks, wodurch die erwähnte Faltenbildung im Bereich der Längsschweißnaht 14 vermieden wird. Diese Falte ist in Figur 2 mit der Bezugsziffer 16 gekennzeichnet.Surprisingly, it has been shown that the risk of wrinkles forming in the area of the weld seam 14 can certainly be avoided by surrounding the outer surface of the weld seam (outer tubular jacket 12) with an elastically stretchable layer 15, for example in the form of a sleeve made of elastically stretchable material, such as hard rubber, rubber, or the like (FIGS. 3 and 4) . In the embodiment according to FIGS. 3 and 4, the sleeve 15 made of elastically stretchable material and drawn over the outer jacket 12 has a greater thickness in the region of the front ends of the capsule 10 than in the region in between. This compensates for the pressurization of the capsule 10 on the face side. The inner diameter of the elastic, stretchable sleeve 15 is somewhat smaller than the outer diameter of the capsule 10 or the outer capsule shell 12, so that it is ensured that the sleeve 15 lies tightly or closely against the outer shell 12 of the capsule 10 and there is a somewhat uniform prestressing thereon exercises. The sleeve 15 made of elastically stretchable material causes an approximately uniform pressure distribution when a cold isostatic pressure is applied, as a result of which the aforementioned wrinkling in the region of the longitudinal weld seam 14 is avoided. This fold is identified in FIG. 2 by reference number 16.

Die Hülse 15 aus elastisch dehnbarem Material ist bei dem Ausführungsbeispiel nach den Figuren 3 und 4 im Bereich der stirnseitigen Enden der Kapsel 10 mittels Schlauchbändern 17 herkömmlicher Art fixiert.The sleeve 15 made of elastically stretchable material is fixed in the embodiment according to FIGS. 3 and 4 in the region of the front ends of the capsule 10 by means of hose bands 17 of a conventional type.

Die elastisch dehnbare Schicht ist ebenfalls relativ dünnwandig. Die Wandstärke entspricht etwa der Wandstärke der Kapselhaut. Vorzugsweise ist die Wandstärke der elastisch dehnbaren Schicht 15 etwa doppelt so groß wie die Wandstärke der Kapselhaut 11 bzw. 12.The elastically stretchable layer is also relatively thin-walled. The wall thickness corresponds approximately to the wall thickness of the capsule skin. The wall thickness of the elastically stretchable layer 15 is preferably approximately twice as large as the wall thickness of the capsule skin 11 or 12.

Sämtliche in den Unterlagen offenbarte Merkmale werden als erfindungswesentlich beansprucht, soweit sie einzeln oder in Kombination gegenüber dem Stand der Technik neu sind.All features disclosed in the documents are claimed as essential to the invention, insofar as they individually or in combination are new compared to the prior art.

Claims (7)

1. Verfahren zur Herstellung pulvermetallurgischer Gegenstände, bei dem Pulver aus Metall und/oder Metall-Legierungen in eine dünnwandige Kapsel eingefüllt, die Kapsel anschließend verschlossen und einem kaltisostatischen Druck ausgesetzt wird, wodurch eine Verdichtung bzw. Verpressung des Pulvers innerhalb der Kapsel erfolgt, so daß ein fester bzw. formbeständiger Gegenstand entsteht,
dadurch gekennzeichnet, daß bei Verwendung einer Kapsel mit einer eine etwa geradlinige Verbindungs-Schweißnaht aufweisenden Mantelfläche diese an ihrer Außenseite vor Aufbringen des kaltisostatischen Drucks mit einer dicht bzw. eng anliegenden elastisch dehnbaren Schicht aus Hartgummi oder entsprechend elastisch dehnbarem Material versehen wird, vorzugsweise derart, daß auf die Mantelfläche eine etwa gleichmäßige Vorspannung aufgebracht wird.1. A process for the production of powder metallurgical objects, in which powders of metal and / or metal alloys are filled into a thin-walled capsule, the capsule is then sealed and subjected to cold isostatic pressure, as a result of which the powder is compressed or compressed within the capsule, so that a solid or dimensionally stable object is created,
characterized in that when using a capsule with An approximately rectilinear connection weld seam has a jacket surface which is provided on the outside before the cold isostatic pressure is applied with a tight or closely fitting elastically stretchable layer of hard rubber or corresponding elastically stretchable material, preferably in such a way that an approximately uniform prestress is applied to the jacket surface becomes. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die die Schweißnaht umfassende Mantelfläche mit einer elastisch dehnbaren Bandage umgeben wird.2. The method according to claim 1, characterized in that the circumferential surface comprising the weld seam is surrounded with an elastically stretchable bandage. 3. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß über die die Schweißnaht aufweisende Mantelfläche eine Hülse aus elastisch dehnbarem Material gezogen bzw. gestülpt wird.3. The method according to claim 1, characterized in that a sleeve made of elastically stretchable material is pulled or put over the jacket surface having the weld seam. 4. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die die Schweißnaht aufweisende Mantelfläche mit einem elastisch dehnbaren Material beschicht wird, das nach dem Auftragen auf die Mantelfläche schrumpft, so daß eine etwa gleichmäßige Vorspannung auf die Mantelfläche aufgebracht wird.4. The method according to claim 1, characterized in that the jacket surface having the weld is coated with an elastically stretchable material which shrinks after application to the jacket surface, so that an approximately uniform bias is applied to the jacket surface. 5. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß bei einer zylindrischen oder rohrförmigen Kapsel die die Schweißnaht umfassende Mantelfläche mit einer elastisch dehnbaren Schicht versehen wird, deren Dicke im Bereich der stirnseitigen Enden der Kapsel größer ist als im Bereich dazwischen.5. The method according to any one of claims 1 to 4, characterized in that in the case of a cylindrical or tubular capsule, the outer surface comprising the weld seam is provided with an elastically stretchable layer, the thickness of which is greater in the region of the front ends of the capsule than in the region in between. 6. Verfahren nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß bei einer zylindrischen oder rohrförmigen Kapsel an den stirnseitigen Enden derselben die elastisch dehnbare Schicht mittels schlauchschellenartiger Haltemittel, Klebestreifen oder dergleichen an der Mantelfläche der Kapsel fixiert wird.6. The method according to any one of claims 1 to 5, characterized in that in the case of a cylindrical or tubular capsule at the front ends the same, the elastically stretchable layer is fixed to the outer surface of the capsule by means of hose clamp-like holding means, adhesive strips or the like. 7. Anwendung des Verfahrens nach einem der Ansprüche 1 bis 6 zur Herstellung von langgestreckten Gegenständen, insbesondere Rohren, deren Außenmantel eine oder mehrere sich in Rohrlängsrichtung erstreckende, etwa geradlinige Schweißnähte aufweist.7. Application of the method according to one of claims 1 to 6 for the production of elongated objects, in particular pipes, the outer jacket of which has one or more, approximately rectilinear weld seams extending in the longitudinal direction of the pipe.
EP84112605A 1983-10-21 1984-10-18 Method of preparing work pieces from metal powder Expired EP0141350B1 (en)

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DE3338369 1983-10-21
DE3338369A DE3338369C1 (en) 1983-10-21 1983-10-21 Process for the manufacture of powder metallurgical objects

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EP0141350A1 true EP0141350A1 (en) 1985-05-15
EP0141350B1 EP0141350B1 (en) 1988-09-07

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JP (1) JPS60145303A (en)
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CN109014219A (en) * 2018-09-14 2018-12-18 河南德源净化装备有限公司 A kind of production method of the powder sintered screen pipe of smooth outer surface type

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US5244623A (en) * 1991-05-10 1993-09-14 Ferro Corporation Method for isostatic pressing of formed powder, porous powder compact, and composite intermediates
AT411580B (en) * 2001-04-11 2004-03-25 Boehler Edelstahl METHOD FOR THE POWDER METALLURGICAL PRODUCTION OF OBJECTS
CN1326387C (en) * 2002-08-20 2007-07-11 松下电器产业株式会社 Bit reduction device
US9234610B2 (en) * 2007-11-07 2016-01-12 Parker-Hannifin Corporation Aluminum foil based hose
US9199308B2 (en) 2011-09-20 2015-12-01 GM Global Technology Operations LLC Method of producing composite articles and articles made thereby
CN109365824B (en) * 2018-10-25 2021-06-25 西安石油大学 Preparation method of 6.5 wt% high-silicon electrical steel thin-wall hollow pipe

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US3551946A (en) * 1968-08-26 1971-01-05 Wah Chang Albany Corp Method and apparatus for compacting isostatically metal particles into solid form
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JPS60145303A (en) 1985-07-31
JPS6340843B2 (en) 1988-08-12
US4565668A (en) 1986-01-21
EP0141350B1 (en) 1988-09-07
DE3473840D1 (en) 1988-10-13
DE3338369C1 (en) 1985-09-26
KR850004035A (en) 1985-07-01

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