US3914981A - Die for hydrostatic extrusion - Google Patents

Die for hydrostatic extrusion Download PDF

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Publication number
US3914981A
US3914981A US543473*A US54347375A US3914981A US 3914981 A US3914981 A US 3914981A US 54347375 A US54347375 A US 54347375A US 3914981 A US3914981 A US 3914981A
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US
United States
Prior art keywords
ring
die
forming portion
composite die
forming
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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US543473*A
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English (en)
Inventor
Jan Nilsson
Pertti Syvakari
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ABB Norden Holding AB
Original Assignee
ASEA AB
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Filing date
Publication date
Application filed by ASEA AB filed Critical ASEA AB
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Publication of US3914981A publication Critical patent/US3914981A/en
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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 OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C25/00—Profiling tools for metal extruding
    • B21C25/02—Dies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/007—Hydrostatic extrusion

Definitions

  • ABSTRACT A composite die for hydrostatic extrusion is composed of a preforming portion with a conical inlet portion and an end-forming portion, separated from each other along a radially dividing plane.
  • a forceabsorbing support ring surrounds that part of the andforming portion which is in contact with and nearest the pre-forming portion. There is a gap on the outside of the part of the end-forming portion remote from the pre-forming portion. Separate rings surround and abut the calibrating end-forming portion and the support ring.
  • the present invention relates to a die for hydrostatic extrusion which is composed of two or more individual parts.
  • the purpose of the invention is to reduce the stresses in and around the die opening and accordingly reduce the risk of rupture and increase the life, and also to facilitate and reduce the cost of the manufacture of the die.
  • the die is particularly intended for hot extrusion where the high temperature of the billet increases the stresses in the die. Different kinds of equipment in which the die may be used are described more fully in, for example, US. Pat. Nos. 3,702,555 and 3,751,958.
  • a die projects into a pressure chamber and rests on a die support which takes up axial forces operating outwardly on the die.
  • the die support also projects somewhat into a cylinder which forms part of the pressure cham' ber.
  • the die is surrounded by the pressure medium which acts on the billet to be extruded.
  • the pressure medium brings about forces acting radially inwardly on the outer surface of the die.
  • the billet to be extruded produces outwardly acting radial forces in the inlet portion of the die.
  • a stress factor greater than two is obtained for thick-walled tubes in case of an outer load, that is, the stresses at the inner surface are more than twice as great as at the outer surface.
  • the outer load itself is great, usually from to kbar.
  • a die manufactured in one piece has also a shape which is less suitable from the point of view of hardening, and must of course have the same high-tensile material in the inlet portion as at the die opening, in spite of the fact that the material in the inlet portion is not subjected to the same high stresses. This results in a bad utilization of the material in the inlet portion of the die.
  • the die is composed of two or more annular portions which are separated by substantially radial dividing lines.
  • a first portion has a conical opening and forms a preforming portion, and a second portion having an opening which closely follows the first portion forms an end-forming and calibrating portion.
  • the end-forming and calibrating portion is surrounded by a third ring and is attached in this ring in a prestressed manner.
  • the prestressing may vary axially so that it is lower at its outer surface than at its inner portion. The same effect can be attained by giving the third ring a smaller axial extension than the endforming and calibrating portion, thus obtaining a suitable balancing of outwardly directed radial forces.
  • the outer limit surface of the end-forming and calibrating portion can advantageously be located immediately behind the smallest cross-section of the die opening. It may then be appropriate to form the die with a third and a fourth ring which make contact with the endforming and calibrating portion and the surrounding prestress ring, respectively. These third and fourth rings are given such dimensions that a radial gap is formed between them. In this way the stress caused by the pressure medium at the opening of the inner ring is reduced.
  • the rings can be made with different thicknesses so that a radial gap is formed between the endforming ring and the ring below the prestress ring. All the annular parts mentioned are held together by a surrounding ring and by locking rings.
  • FIGS. 1 and 2 show dies of different embodiments placed in a pressure chamber in a press of the kind described in US. Pat. No. 3,751,958.
  • FIGS. 1 designates a press table in a press stand, the rest of which is not shown, and 2 a highpressure cylinder which is part of a high-pressure chamber.
  • a support cylinder 3 for taking up forces from a tube mandrel
  • a seal 4 consisting of an inner sealing ring 4a and an outer sealing ring 4b
  • a spacing tube 5 which holds the seal 4a, 4b axially fixed to the seal holder 6.
  • a die support 7 rests on the press table 1 and projects into the cylinder 2.
  • the die support is provided with a guide ring 8 for centering a die 9a, which rests on the die support 7.
  • the die 9a consists of a plurality of annular parts.
  • the part 10 forms a preforming portion and has a concial opening 11. Below this there is an annular end-forming and calibrating portion 12 with a conical opening 13 which closely conforms to the opening 11 in the preforming portion 10. Furthermore, there are a substantially cylindrical opening 14 and, below this, a portion 15 with a somewhat larger diameter than the opening 14.
  • the part 12 is surrouonded by a ring 16 and is attached into this ring at least along part of its axial extension.
  • the support ring 16 has a smaller thickness than the end-forming portion 12, so that the ring is engaged into the part of the portion 12 nearest to the preforming portion 10 but not in its outermost part.
  • the preforming portion 10, the end-forming and calibrating portion 12 and the attachment ring 16 are held together by a ring 17 and by locking rings 18 and -19.
  • the die support 7 is formed with support surfaces 21 and 22 in different planes at the same axial spacing as the outer surfaces of the parts 12 and 16. Between the outer cylindrical surface of the end-forming portion 12 and the step between the surfaces 21 and 22 there is a gap 23 so that the die support 7 can be compressed radially without coming into contact with the outer cylindrical surface of the end-forming portion 12.
  • the billet when it is pressed against the conical openings 11 and 13 of the die during insertion, is prevented from giving rise to tensile stresses in the end-forming portion 12, which stresses might cause said portion to burst.
  • the shape of the die causes the ring 16 and the pressure medium acting thereon to operate only on that part of the end-forming portion 12 which is exposed to outwardly directed radial forces during the pressing, that is, substantially only on the part which is located outside the conical portion 13 and the die opening portion 14.
  • the shape of the die also means that the pressure medium is prevented from causing dangerous compressive stresses in the clearance portion in the die opening where there are no radially outwardly directed forces during the pressing.
  • the die 9b contains a preforming portion 10, an end-forming portion 12 with a prestressed support ring 16 and also two rings and 26.
  • the outer end surfaces of these rings are located at the same plane.
  • the ring 26 has thus a greater thickness than the ring 25.
  • the outer diameter of the ring 25 is smaller than the inner diameter of the ring 26, so that a radial gap 27 is formed.
  • the ring 26 is formed with a radially inwardly directed flange 28 which projects into a recess 29 in the ring 25 in order to fix this ring axially.
  • the parts of the die are held together by a ring 30 and two locking rings 31 and 32. Because of the gap 27 between the ring 25 and the ring 26, the ring 26 must be deformed radially under the action of the pressure medium around the die before it is pressed against the ring 25. If possible, the play between the ring 26 and the ring 12 should be so large that said rings do not make contact with each other during the pressing. In this way it is possible to limit the stress caused by the pressure medium in the ring 12 and in the opening in the ring 25. When a die of this design is used, the end surface 34 of the die is of course completely plane.
  • One further advantage of a composite die according to the invention is that different materials can be chosen for different parts of the die. This means that a material of very high strength can be chosen in the endforming and calibrating portion of the die, and that this part can be given improved properties more easily by heat treatment because of its relatively small dimensions, which results in a reduced risk of dangerous stresses due to the heat treatment, and thus higher strength. It will also be possible to use hard metal in the die, or other materials which can be manufactured in the large sizes required for an undivided die only with considerable difficulty. The die will also be less sensi tive to such heat shocks which arise from contact with a heated extrusion billet. The cost of the die is also reduced by the fact that relatively inexpensive materials can be used in the main part of the die. In case of damage to the die, normally only the end-forming and calibrating portion of the die needs to be replaced. Further, the same elements can be used to a great extent for extruding products of different cross-sectional areas.
  • Composite die according to claim 1 which comprises a fourth ring (25) and a fifth ring (26) on the outside of the fourth ring, said fourth and fifth rings axially abutting the calibrating portion (12) and the support ring (16), respectively.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Extrusion Of Metal (AREA)
  • Forging (AREA)
  • Press-Shaping Or Shaping Using Conveyers (AREA)
US543473*A 1974-01-29 1975-01-23 Die for hydrostatic extrusion Expired - Lifetime US3914981A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE7401110A SE390902B (sv) 1974-01-29 1974-01-29 Matris for hydrostatisk strengpressning

Publications (1)

Publication Number Publication Date
US3914981A true US3914981A (en) 1975-10-28

Family

ID=20320035

Family Applications (1)

Application Number Title Priority Date Filing Date
US543473*A Expired - Lifetime US3914981A (en) 1974-01-29 1975-01-23 Die for hydrostatic extrusion

Country Status (11)

Country Link
US (1) US3914981A (sv)
JP (1) JPS5512329B2 (sv)
BE (1) BE824857A (sv)
CA (1) CA1021288A (sv)
DE (1) DE2501485A1 (sv)
ES (1) ES434231A1 (sv)
FR (1) FR2258909B1 (sv)
GB (1) GB1487802A (sv)
IT (1) IT1027393B (sv)
NL (1) NL7500931A (sv)
SE (1) SE390902B (sv)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4016737A (en) * 1974-12-06 1977-04-12 Allmanna Svenska Elektriska Aktiebolaget High pressure press
US4038849A (en) * 1974-12-06 1977-08-02 Asea Aktiebolag High pressure press
US4041744A (en) * 1974-12-06 1977-08-16 Asea Aktiebolag High pressure press
US4041743A (en) * 1974-12-06 1977-08-16 Asea Aktiebolag High pressure press
US4195505A (en) * 1977-11-22 1980-04-01 Asea Ab Press for hydrostatic extrusion of tubes
US4397080A (en) * 1980-11-10 1983-08-09 Me-U-Sea, Inc. Process for preparation of support tooling for extrusion dies
US4543812A (en) * 1982-02-25 1985-10-01 The Harris-Thomas Drop Forge Company Forging apparatus

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1015913A (en) * 1910-01-04 1912-01-30 John Stratton Apparatus for drawing wire.
US3109663A (en) * 1962-03-27 1963-11-05 American Carbide Company Die assemblies
US3191374A (en) * 1961-12-15 1965-06-29 Anaconda Wire & Cable Co Forming die
US3691816A (en) * 1969-06-25 1972-09-19 Per-Olof Strandell Moulds

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1015913A (en) * 1910-01-04 1912-01-30 John Stratton Apparatus for drawing wire.
US3191374A (en) * 1961-12-15 1965-06-29 Anaconda Wire & Cable Co Forming die
US3109663A (en) * 1962-03-27 1963-11-05 American Carbide Company Die assemblies
US3691816A (en) * 1969-06-25 1972-09-19 Per-Olof Strandell Moulds

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4016737A (en) * 1974-12-06 1977-04-12 Allmanna Svenska Elektriska Aktiebolaget High pressure press
US4038849A (en) * 1974-12-06 1977-08-02 Asea Aktiebolag High pressure press
US4041744A (en) * 1974-12-06 1977-08-16 Asea Aktiebolag High pressure press
US4041743A (en) * 1974-12-06 1977-08-16 Asea Aktiebolag High pressure press
US4195505A (en) * 1977-11-22 1980-04-01 Asea Ab Press for hydrostatic extrusion of tubes
US4397080A (en) * 1980-11-10 1983-08-09 Me-U-Sea, Inc. Process for preparation of support tooling for extrusion dies
US4543812A (en) * 1982-02-25 1985-10-01 The Harris-Thomas Drop Forge Company Forging apparatus

Also Published As

Publication number Publication date
SE7401110L (sv) 1975-07-30
FR2258909A1 (sv) 1975-08-22
FR2258909B1 (sv) 1980-07-18
JPS50140356A (sv) 1975-11-11
IT1027393B (it) 1978-11-20
GB1487802A (en) 1977-10-05
JPS5512329B2 (sv) 1980-04-01
NL7500931A (nl) 1975-07-31
DE2501485A1 (de) 1975-07-31
SE390902B (sv) 1977-01-31
CA1021288A (en) 1977-11-22
BE824857A (fr) 1975-05-15
ES434231A1 (es) 1976-12-16

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