EP0349524A2 - Mandrin d'extrusion et procédé de sa fabrication - Google Patents

Mandrin d'extrusion et procédé de sa fabrication Download PDF

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Publication number
EP0349524A2
EP0349524A2 EP89890174A EP89890174A EP0349524A2 EP 0349524 A2 EP0349524 A2 EP 0349524A2 EP 89890174 A EP89890174 A EP 89890174A EP 89890174 A EP89890174 A EP 89890174A EP 0349524 A2 EP0349524 A2 EP 0349524A2
Authority
EP
European Patent Office
Prior art keywords
outer layer
mandrel
extrusion
mandrel body
metal composite
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Withdrawn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
EP89890174A
Other languages
German (de)
English (en)
Other versions
EP0349524A3 (fr
Inventor
Bruno Dipl.-Ing. Hribernik
Johann Dipl.-Ing. Stamberger
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.)
Boehler GmbH
Boehler GmbH Germany
Original Assignee
Boehler GmbH
Boehler GmbH Germany
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 Boehler GmbH, Boehler GmbH Germany filed Critical Boehler GmbH
Publication of EP0349524A2 publication Critical patent/EP0349524A2/fr
Publication of EP0349524A3 publication Critical patent/EP0349524A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C25/00—Profiling tools for metal extruding
    • B21C25/04—Mandrels
    • 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
    • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
    • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools

Definitions

  • the invention relates to an extrusion mandrel for the production of pipes or tubular bodies at higher temperatures and a method for the production of extrusion mandrels for the production of pipes.
  • Extrusion mandrels for example, have a length of 1 m and a diameter of approximately 40 to 80 mm.
  • the material from which they are made should have the best possible wear properties at higher temperatures and, among other things, be creep-resistant and resistant to thermal shock, so that hot-work steel is usually used.
  • the mandrels made from hot-work steel are hardened at least once or cooled from their austenitizing temperature and tempered at least once, preferably twice, in order to achieve the appropriate toughness and working hardness.
  • the extrusions to be extruded have temperatures of 400 to 900 ° C, if they are non-ferrous alloys, and of 900 to 1250 ° C, if they are, for example, iron-based alloys or nickel-based alloys.
  • the extrusion mandrels get surface temperatures that can be higher than the tempering temperature of the hot-work steel (for example, above 600 ° C), causing the hardness of the area of the mandrel near the surface to drop.
  • the usual hardness at room temperature drops from 46 to 51 HRC to ⁇ 30 HRC.
  • Extrusion mandrels made from a hard alloy e.g. made of co-hard alloys, have a relatively good hardness (33 HRC) at high temperatures, e.g. 600 ° C.
  • these extrusion mandrels have poor creep resistance, low toughness (in the cast state approximately 5 Nm / cm2) so that they cannot be used well for production processes, because the risk of breakage, in particular in the case of cooled mandrels, is insufficient due to the thermal shock and their toughness and there is a risk of machine damage.
  • Nickel-based hard alloys have low hot hardness at high temperatures such as> 600 ° C. They also have poor creep resistance and toughness. These hard alloys cannot be used well for production either.
  • the object of the invention is to provide an extrusion mandrel or a method for producing extrusion mandrels which have high hardness, toughness and abrasion resistance even at high surface temperatures above 600 ° C. and a correspondingly long service life. Furthermore, the risk of breakage should be minimal and the thermal shock sensitivity of the mandrels should be correspondingly high and independent of the various types of cooling of the mandrel, e.g. Internal cooling or spraying of cooling water. Furthermore, there should be no bending of the extrusion mandrels when the temperature changes, since otherwise the pipes produced would have different wall thicknesses.
  • an extrusion mandrel of the type mentioned at the outset is characterized in that the extrusion mandrel has a mandrel body which has an outer layer is provided, which is connected to the mandrel body to form a composite metal layer or is connected to the mandrel body by a metallic bond.
  • a method of the type mentioned at the outset is characterized in that the mandrel body is covered with an outer layer to form a metal composite.
  • a preferred embodiment of an extrusion mandrel is characterized in that the mandrel body is made of hot-work steel, e.g. DIN material no. 1.2343 or DIN material no. 1.6358, and an outer layer made of a precipitation-hardenable alloy based on nickel or cobalt, preferably based on cobalt, is applied to the mandrel body to form a metallic bond.
  • An outer layer made of a cobalt-based alloy is preferred due to the high hardness of this alloy.
  • This outer layer is firmly connected to the mandrel body to form a metal composite. This outer layer surrounds the mandrel body at least on its side surfaces.
  • This outer layer can preferably be produced by powder metallurgy, for example by sintering, spray casting, hot isostatic pressing, forging, rolling, extruding, plating, explosive plating, etc. of alloy powders.
  • the extrusion mandrel is tempered or hardened and tempered, the heat treatment at de materials is matched. This involves austenitizing, cooling and tempering the mandrel body, as well as solution annealing and precipitation hardening of the outer layer. This procedure results in an extremely hard and wear-resistant layer being formed on the mandrel body, which achieves high hardness and toughness, but which can withstand the highest stresses due to the metal composite, without peeling off or impairing the adhesion to the mandrel body.
  • the extrusion mandrel offers high toughness and thermal shock resistance, whereby the outer layer has correspondingly high hardness and wear resistance and thus advantageous usage properties are achieved.
  • the shape of the extrusion mandrels produced in this way can be any; the mandrels can be round, oval, rectangular, square, polygonal or have a different cross section.
  • the metal composite layer or the metal composite between the mandrel body and the applied outer layer is homogeneous and largely free of brittle precipitations, which would reduce the adhesion between the mandrel body and the outer layer.
  • the advantageous properties of the extrusion mandrel according to the invention are u.a. due to the fact that brittle precipitates in the metal composite layer do not impair the composite.
  • the alloy used for the outer layer has a small or a lower coefficient of thermal conductivity and / or no conversion in comparison with the alloy used for the mandrel body having.
  • a small coefficient of thermal conductivity of the outer layer is advantageous, because it means that the high temperatures of the outer layer that occur in the course of the production of pipes are not, or not entirely, transferred to the mandrel body, which thus hardness, toughness and its good properties due to excessively high temperatures or not lost by starting.
  • a small coefficient of thermal conductivity and / or the lack of conversion of the outer layer is advantageous when the outer layer of the extrusion mandrels is additionally hardened.
  • the surface of the outer layer of the extrusion mandrels can be brought briefly to the excretion temperature (for example about 800 ° C.), but the mandrel body remains below the tempering temperature. It is also advantageous if the material of the outer layer has a greater coefficient of thermal expansion than the mandrel body material. In any case, however, only the outer layer should be heated or a temperature transition from the outer layer to the mandrel body should be kept as low as possible, since heating the mandrel body above approximately 550 ° C. impairs its properties.
  • the surface zone of the outer layer is increased by induction, a flame blower or the like, if necessary often, to temperatures in the range from 650 to 850 ° C., in particular from 740 to 820 ° C., in order to achieve precipitation hardening by briefly heating the surface, but without increasing the core temperature above 550 ° C.
  • An extrusion mandrel constructed in this way has the advantage that, during operation, the surface material hardens further due to the friction and contact with the hot alloys to be pressed. It had been shown that this results in considerable increases in the hardness of the outer layer, without however causing thermal fatigue.
  • the powder metallurgical production of the outer layer can in particular take place in the course of a hot deformation, e.g. Hot forging, hot rolling, etc., with a reduction in the cross section of the mandrel body.
  • a hot deformation e.g. Hot forging, hot rolling, etc.
  • the thickness of the applied outer layer is approximately 1.5 to 25 mm, preferably 4 to 10 mm. It is taken into account that, if the layer thickness is too low, the core material may become too hot, which would then become soft. However, if the outer layer is dimensioned too thick, there is a risk of breakage. Care is also taken to ensure that the eccentricity of the surface layer is a maximum of 2.5 mm, in particular a maximum of 1 mm, because otherwise the extrusion mandrel will bend when heated. However, it was found that mandrels produced according to the invention can easily be classified within these tolerances. It is also advantageous if consideration is given to a homogeneous structure of the outer layer.
  • the metal composite layer formed by diffusion between the mandrel body and the outer layer is not a brittle intermediate layer, but an elastic layer which even compensates for different thermal expansions of the mandrel body and the outer layer without difficulty.
  • An effect of different coefficients of thermal expansion of the materials of the mandrel body and the outer layer could not run in particular when producing a round composite or in cross section the thorn are observed; chipping of the outer layer or cracking in the outer layer were not observed.
  • precipitation-hardenable cobalt or nickel-based alloys such as, for example, come as material for the outer layer and the mandrel body. Stellite, in question.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Extrusion Of Metal (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Powder Metallurgy (AREA)
EP19890890174 1988-07-01 1989-06-23 Mandrin d'extrusion et procédé de sa fabrication Withdrawn EP0349524A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT1708/88 1988-07-01
AT170888A ATA170888A (de) 1988-07-01 1988-07-01 Strangpressdorn und verfahren zu seiner herstellung

Publications (2)

Publication Number Publication Date
EP0349524A2 true EP0349524A2 (fr) 1990-01-03
EP0349524A3 EP0349524A3 (fr) 1990-12-05

Family

ID=3519270

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890890174 Withdrawn EP0349524A3 (fr) 1988-07-01 1989-06-23 Mandrin d'extrusion et procédé de sa fabrication

Country Status (3)

Country Link
EP (1) EP0349524A3 (fr)
AT (1) ATA170888A (fr)
AU (1) AU622458B2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0656235A1 (fr) * 1993-12-01 1995-06-07 Sumitomo Light Metal Industries Limited Filière d'extrusion pour l'extrusion d'éléments creux en alliage d'aluminium contenant du zinc
EP3057721A1 (fr) * 2013-10-16 2016-08-24 Ulrich Bruhnke Extrudeuse pour fabriquer des tôles planes

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE610053C (de) * 1931-04-12 1935-09-16 Fritz Singer Dr Lochdorn fuer das Strangpressen von Rohren
US3541831A (en) * 1967-04-07 1970-11-24 Int Nickel Co Extrusion mandrel
CH538311A (de) * 1972-03-30 1973-06-30 Alusuisse Pressmatrize
US4090873A (en) * 1975-01-23 1978-05-23 Nippon Gakki Seizo Kabushiki Kaisha Process for producing clad metals

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0656235A1 (fr) * 1993-12-01 1995-06-07 Sumitomo Light Metal Industries Limited Filière d'extrusion pour l'extrusion d'éléments creux en alliage d'aluminium contenant du zinc
US5664453A (en) * 1993-12-01 1997-09-09 Sumitomo Light Metal Industries, Ltd. Hollow extruder die for extruding a hollow member of a zinc-containing aluminum alloy
EP3057721A1 (fr) * 2013-10-16 2016-08-24 Ulrich Bruhnke Extrudeuse pour fabriquer des tôles planes

Also Published As

Publication number Publication date
EP0349524A3 (fr) 1990-12-05
AU622458B2 (en) 1992-04-09
ATA170888A (de) 1993-03-15
AU3725289A (en) 1990-01-04

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