US3640111A - Press for hydrostatic extrusion having a composite cylinder externally excused to high pressure - Google Patents

Press for hydrostatic extrusion having a composite cylinder externally excused to high pressure Download PDF

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Publication number
US3640111A
US3640111A US11479A US3640111DA US3640111A US 3640111 A US3640111 A US 3640111A US 11479 A US11479 A US 11479A US 3640111D A US3640111D A US 3640111DA US 3640111 A US3640111 A US 3640111A
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pressure
press
die
tubular element
tubes
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US11479A
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Hans Lundstrom
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ABB Norden Holding AB
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ASEA AB
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/001—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a flexible element, e.g. diaphragm, urged by fluid pressure; Isostatic presses
    • 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

  • a press for hydrostatic extrusion includes a press stand and a hi 'gh pressure cylinder arranged in the press stand. These parts form a pressure chamber to enclose a pressure medium, and a 5 Claims, Drawing Figures PATENTED FEB 8
  • the present invention relates to a press for hydrostatic extrusion having a tubular member externally exposed to a high pressure.
  • hollow cylinders suitable for die supports and the like can be manufactured, in which lower tangential stress is obtained at the inner surface than when support it is usually constructed so that its outer tube takes up the axial forces operating on the die.
  • the tangential stress at the inner surface of the cylinder is considerably reduced. If the axial stress in the cylinder is assumed to be zero, with a construction having two tubes, one inside the other and a suitable gap between the tubes, the condition being fulfilled that the equivalent tensile stress at the inner edge of both tubes is equal and as small as possible, and that the ratio between the thickness of the material in the tubes is optimally selected, the maximum tangential pressure stress at the inner radius of the tubes will be where r the outer radius of the composite cylinder.
  • FIG. 1 shows schematically a press for hydrostatic extrusion where the die support is used as a punch which can be inserted into a pressure chamber.
  • FIG. 2 shows on a larger scale the die support itself.
  • FIG. 3 shows a press having a pressure-multiplier.
  • FIG. 4 shows a detail of an ordinary extrusion press having a die support according to the invention.
  • FIG. 5 shows an embodiment in which the die itself and the die support form an integrated unit.
  • FIG. 1 designates a press piston and 2 a press table on a horizontal hydraulic press, not otherwise shown.
  • the press comprises a pressure-generating punch 3 which is firmly attached to the piston I by means of a clamping ring 4 and a stationary punch 5 which is attached to the press table 2 by means of a clamping ring 6.
  • the punch 5 forms a support for a die 7.
  • the pressure cylinder 8 is axially displaceable and is forced in over the stationary punch 5 of the piston I when the punch 3 has been completely inserted in the cylinder 8.
  • the punch according to the invention consists of two concentric tubes 10 and '11 between which at the innermost part of the punch is a seal 12 which prevents pressure medium from penetrating between the tubes.
  • the outer diameter of the tube 11 is smaller than the inner diameter of the tube 10 so that-a'gap I3 exists between the tubes when the punch is not (r the tangential stress for a cylinder constructed of two loaded.
  • the tube Ill is somewhat shorter than the tube 10 and it will therefore take up all the axial force operating on the die 7 during the compression.
  • 21 designates a pressure-generating punch and 22 a press table in a press not otherwise shown.
  • the compression equipment is intended for hydrostatic extrusion at ultrahigh pressure, by which is meant pressures in the order of magnitude of 25 kilobar or more.
  • On the press table 22 rests a high-pressure cylinder, usually the type comprising an inner tube 23 surrounded by a prestressed strip sheath 24.
  • the punch 21 projects into the tube 23 of the cylinder and generates a pressure in a pressure medium enclosed in the cylinder space 25.
  • In the cylinder is a unit consisting of a pressure multiplier and a pressure chamber 27.
  • the pressure multiplier 26 comprises a differential piston 28 which is axially movable in a chamber with a space 29 filled with gas under low pressure or partly or entirely evacuated. In accordance with the invention, this is formed of two concentric tubes 39 and 31 between which is a gap 32 when the chamber is not loaded. At the upper and lower parts of the chamber are rings 33 and 34. Between the ring 33 and the piston 28 is a sealing ring 35.
  • the pressure chamber 27 consists of an inner tube 36 and an outer prestressed tube 37. In the pressure chamber is a die 38 and also a billet 39.
  • the space 40 is filled with a pressure medium which hydrostatically presses against the billet 39.
  • the entire unit of pressure multiplier 26 and pressure chamber 27 is surrounded by a tube M which is connected to the ring 33 by a weld 42. Between the pressure chamber tube 23 and the sealing tube 41 is a sealing ring 43 and a support ring 44 for the sealing ring. Between the die 38 and the tube 36 is a sealing ring and between the piston 28 and the cylinder 36 is a sealing ring 45.
  • the space 29 for the pressure multiplier is sealed from the space 25 filled with pressure medium in the outer pressure chamber by the tube 41 and the piston 28 with the seal 35. It is also sealed from the space 40 in the enclosed pressure chamber 27 by the lower part of the piston 28 with the seal 45.
  • the piston 21 is pressed into the. space 25 of the high-pressure chamber and generates a pressure which externally influences the pressure multiplier 26 which is constructed in accordance with the invention with tubes 30 and 31 between which is a gap 32 when the pressure of the presing into the high-pressure cylinder, and a guide54.
  • a gasket 55 Between the high-pressure cylinder 51 and the part 53 is a gasket 55.
  • a die 56 rests on a die support consisting of an outer short tube or ring 57 and an inner tube or ring 58. Between these is a gap 59 when the pressure in the space 60 is low. This gap disappears when the pressure increases so that the ring 57 is compressed and its diameter decreases. At high pressure it will then be supported by the ring 58.
  • the joint between the die 56 and the ring 57 is covered by a sleeve 61 of elastomeric material which prevents pressure medium in the space 60 from penetrating between the die 56 and the ring 57.
  • a seal 62 which prevents pressure medium from passing between the die support and the part 53.
  • the guide 54 centers the die support with respect to the opening 63 in the plate 52. Because of the structure shown, the distance between the extrusion edge 64 and the base surface of the die 56 can be kept very short, thus preventing the material around the hole in the die under the extrusion edge from being plastically deformed during the extrusion. This plastic deformation would result in a tangential tensile stress upon decompression which might give rise to radial cracks along the extrusion edge 64, the die being thus damaged.
  • the die and die support are an integrated unit.
  • the die 70 is externally conical at its lower part and surrounded at this part by an internally conical ring 71.
  • the cone angles of the die 70 and the ring 71 are selected so that at least in the area under the extrusion edge 64 a gap 73 is formed.
  • a press for hydraulic extrusion comprising a press stand, a highpressure cylinder part arranged in the press stand, a tubular element extending into the interior of the high-pressure cylinder and spaced inwardly from the wall thereof, at least a part of said tubular element comprising at least inner and outer tubes arranged one inside the other having an annular space therebetween and means sealing the annular space from the interior of the high-pressure cylinder, and means to produce in the high-pressure cylinder on the outside of the outer tube a pressure substantially greater than the pressure existing between the tubes, whereby contact between the tubes is caused when the outer tube is subjected to pressure above a predetermined amount.
  • the tubular element comprises a pressure-amplifier (26).

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Shaping Metal By Deep-Drawing, Or The Like (AREA)
  • Extrusion Of Metal (AREA)
  • Press-Shaping Or Shaping Using Conveyers (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)

Abstract

A press for hydrostatic extrusion includes a press stand and a high-pressure cylinder arranged in the press stand. These parts form a pressure chamber to enclose a pressure medium, and a piston is provided extending into the chamber for effecting a pressure in the enclosed pressure medium. A tubular element having a die at its inner end projects into the pressure chamber on the opposite end from the piston. The tubular element is formed of a number of tubes arranged one inside the other between which is an annular gap when the tubular element is unloaded; but the tubes come into contact when the outer part is subjected to working pressure.

Description

Muted States Patent 1151 aesmn Lundstrom Web. 8, W72
[54] PRESS Mm HYDRQSTATH v [56] References (Titled EXTRUSKUN HAVING A CUMHUSHTE UNITED STATES PATENTS CYLINDER EXTERNALLY EXCUSEH 3,354,685 11/1967 Green ..72/60 TO HIGH PRESSURE Hans Lundstrom, Robertsfors, Sweden Allrnanna Svenslra Eleldrislta Aktielmloget, Vasteras, Sweden Feb. 16, 1970 Inventor:
Assignee:
Filed:
Appl. No.:
Foreign Application Priority Data Primary EiaminerRichard J. Herbst Attorney1ennings Bailey, Jr.
Feb. 14, 1969 Sweden ..2024/69 U.S. Cl ..72/60, 72/271, 72/273 Int. Cl. B216 27/00 Field of Search ..72/60, 253, 271, 273
[ ABSTRACT I A press for hydrostatic extrusion includes a press stand and a hi 'gh pressure cylinder arranged in the press stand. These parts form a pressure chamber to enclose a pressure medium, and a 5 Claims, Drawing Figures PATENTED FEB 8|87Z 3,640,111
sum 2 OF 3 INVENIOR. HAN 6 L \JN D317? 0 PATENTEUFEB em:
SHEET 3 OF 3 1 mass iron nvnnosrarrc EXTRUSKON KIAVHNGA COMPOSITE CYLINDER EXTERNALLY EXCUSED TO I HIGH PRESSURE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press for hydrostatic extrusion having a tubular member externally exposed to a high pressure.
2. The Prior Art In presses for hydrostatic extrusion the length of the pressure-generating punch is limited by the buckling strength.
Thus the volume which can be pressed in one operating cycle is also limited. In order to be able to increase the billet length which can be extruded with a certain maximum punch length,
presses have in certain cases been designed in such a way that,
face of a tube which is subjected to an external overpressure is at least twice as great as the external overpressure. According to the elasticity theory:
1- F y where o the tangential stress for a simple tube p the external pressure r, inner radius r, outer radius At an external overpressure of kilobar the tangential stress is at least 600 kg./mm. at the inner surface of the tube if it is not plastically deformed at the inner surface previously. if it is plastically deformed, tensile stresses occur upon decompression which, with the hard material which must normally be used, cause cracking at the inner surface, and gradually rupture.
SUMMARY OF THE INVENTION By means of the invention, hollow cylinders suitable for die supports and the like can be manufactured, in which lower tangential stress is obtained at the inner surface than when support it is usually constructed so that its outer tube takes up the axial forces operating on the die.
In the embodiment according to the invention the tangential stress at the inner surface of the cylinder is considerably reduced. If the axial stress in the cylinder is assumed to be zero, with a construction having two tubes, one inside the other and a suitable gap between the tubes, the condition being fulfilled that the equivalent tensile stress at the inner edge of both tubes is equal and as small as possible, and that the ratio between the thickness of the material in the tubes is optimally selected, the maximum tangential pressure stress at the inner radius of the tubes will be where r the outer radius of the composite cylinder The advantage of a double-walled cylinder in comparison with a single-walled cylinder is clear from the following table:
where o is the tangential stress of the inner radius of a singlewalled cylinder.
,It is possible to use more than two tubes and thus further reduce the maximum tangential pressure stress.
BRIEF DESCRIPTION OF THE DRAWINGS The invention is further described with reference to the accompanying drawings.
FIG. 1 shows schematically a press for hydrostatic extrusion where the die support is used as a punch which can be inserted into a pressure chamber.
FIG. 2 shows on a larger scale the die support itself.
FIG. 3 shows a press having a pressure-multiplier.
1 FIG. 4 shows a detail of an ordinary extrusion press having a die support according to the invention.
FIG. 5 shows an embodiment in which the die itself and the die support form an integrated unit.
' DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings 1 designates a press piston and 2 a press table on a horizontal hydraulic press, not otherwise shown. The press comprises a pressure-generating punch 3 which is firmly attached to the piston I by means of a clamping ring 4 and a stationary punch 5 which is attached to the press table 2 by means of a clamping ring 6. The punch 5 forms a support for a die 7. The pressure cylinder 8 is axially displaceable and is forced in over the stationary punch 5 of the piston I when the punch 3 has been completely inserted in the cylinder 8.
. The part of the punch 5 which is inside the seal 9 will be subjected to an external overpressure by the pressure medium enclosed in the cylinder. In order to be able to withstand the high pressure the punch according to the invention consists of two concentric tubes 10 and '11 between which at the innermost part of the punch is a seal 12 which prevents pressure medium from penetrating between the tubes. The outer diameter of the tube 11 is smaller than the inner diameter of the tube 10 so that-a'gap I3 exists between the tubes when the punch is not (r the tangential stress for a cylinder constructed of two loaded. The tube Ill is somewhat shorter than the tube 10 and it will therefore take up all the axial force operating on the die 7 during the compression.
1 In FIG. 3, 21 designates a pressure-generating punch and 22 a press table in a press not otherwise shown. The compression equipment is intended for hydrostatic extrusion at ultrahigh pressure, by which is meant pressures in the order of magnitude of 25 kilobar or more. On the press table 22 rests a high-pressure cylinder, usually the type comprising an inner tube 23 surrounded by a prestressed strip sheath 24. The punch 21 projects into the tube 23 of the cylinder and generates a pressure in a pressure medium enclosed in the cylinder space 25. In the cylinder is a unit consisting of a pressure multiplier and a pressure chamber 27. The pressure multiplier 26 comprises a differential piston 28 which is axially movable in a chamber with a space 29 filled with gas under low pressure or partly or entirely evacuated. In accordance with the invention, this is formed of two concentric tubes 39 and 31 between which is a gap 32 when the chamber is not loaded. At the upper and lower parts of the chamber are rings 33 and 34. Between the ring 33 and the piston 28 is a sealing ring 35. The pressure chamber 27 consists of an inner tube 36 and an outer prestressed tube 37. In the pressure chamber is a die 38 and also a billet 39. The space 40 is filled with a pressure medium which hydrostatically presses against the billet 39. The entire unit of pressure multiplier 26 and pressure chamber 27 is surrounded by a tube M which is connected to the ring 33 by a weld 42. Between the pressure chamber tube 23 and the sealing tube 41 is a sealing ring 43 and a support ring 44 for the sealing ring. Between the die 38 and the tube 36 is a sealing ring and between the piston 28 and the cylinder 36 is a sealing ring 45.
The space 29 for the pressure multiplier is sealed from the space 25 filled with pressure medium in the outer pressure chamber by the tube 41 and the piston 28 with the seal 35. It is also sealed from the space 40 in the enclosed pressure chamber 27 by the lower part of the piston 28 with the seal 45.
During the extrusion the piston 21 is pressed into the. space 25 of the high-pressure chamber and generates a pressure which externally influences the pressure multiplier 26 which is constructed in accordance with the invention with tubes 30 and 31 between which is a gap 32 when the pressure of the presing into the high-pressure cylinder, and a guide54. Between the high-pressure cylinder 51 and the part 53 is a gasket 55.
In the embodiment according to FIG. 4 a die 56 rests on a die support consisting of an outer short tube or ring 57 and an inner tube or ring 58. Between these is a gap 59 when the pressure in the space 60 is low. This gap disappears when the pressure increases so that the ring 57 is compressed and its diameter decreases. At high pressure it will then be supported by the ring 58. The joint between the die 56 and the ring 57 is covered by a sleeve 61 of elastomeric material which prevents pressure medium in the space 60 from penetrating between the die 56 and the ring 57. Between the ring 57 and'the part 53 of the disc 52 is a seal 62 which prevents pressure medium from passing between the die support and the part 53. The guide 54 centers the die support with respect to the opening 63 in the plate 52. Because of the structure shown, the distance between the extrusion edge 64 and the base surface of the die 56 can be kept very short, thus preventing the material around the hole in the die under the extrusion edge from being plastically deformed during the extrusion. This plastic deformation would result in a tangential tensile stress upon decompression which might give rise to radial cracks along the extrusion edge 64, the die being thus damaged.
In the embodiment according to FIG. 5, the die and die support are an integrated unit. The die 70 is externally conical at its lower part and surrounded at this part by an internally conical ring 71. The cone angles of the die 70 and the ring 71 are selected so that at least in the area under the extrusion edge 64 a gap 73 is formed.
I claim:
1. A press for hydraulic extrusion comprising a press stand, a highpressure cylinder part arranged in the press stand, a tubular element extending into the interior of the high-pressure cylinder and spaced inwardly from the wall thereof, at least a part of said tubular element comprising at least inner and outer tubes arranged one inside the other having an annular space therebetween and means sealing the annular space from the interior of the high-pressure cylinder, and means to produce in the high-pressure cylinder on the outside of the outer tube a pressure substantially greater than the pressure existing between the tubes, whereby contact between the tubes is caused when the outer tube is subjected to pressure above a predetermined amount.
2. Press according to claim 1, in which the tubular element comprises a pressure-amplifier (26).
3. Press according to claim 1, having an extrusion die, the tubular element (5) forming a support for the extrusion die (7) and taking up axial forces operating on the die.
4. Press according to claim 1, in which the inner part of the tubular element comprises a die 5. Press according to claim 1, in which the tubular element is composed of conical tube parts (70, 71

Claims (5)

1. A press for hydraulic extrusion comprising a press stand, a high-pressure cylinder part arranged in the press stand, a tubular element extending into the interior of the high-pressure cylinder and spaced inwardly from the wall thereof, at least a part of said tubular element comprising at least inner and outer tubes arranged one inside the other having an annular space therebetween and means sealing the annular space from the interior of the high-pressure cylinder, and means to produce in the high-pressure cylinder on the outside of the outer tube a pressure substantially greater than the pressure existing between the tubes, whereby contact between the tubes is caused when the outer tube is subjected to pressure above a predetermined amount.
2. Press according to claim 1, in which the tubular element comprises a pressure-amplifier (26).
3. Press according to claim 1, having an extrusion die, the tubular element (5) forming a support for the extrusion die (7) and taking up axial forces operating on the die.
4. Press according to claim 1, in which the inner part of the tubular element comprises a die (70).
5. Press according to claim 1, in which the tubular element is composed of conical tube parts (70, 71).
US11479A 1969-02-14 1970-02-16 Press for hydrostatic extrusion having a composite cylinder externally excused to high pressure Expired - Lifetime US3640111A (en)

Applications Claiming Priority (1)

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SE2024/69A SE344287B (en) 1969-02-14 1969-02-14

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JP (1) JPS5020956B1 (en)
DE (1) DE2006017C3 (en)
GB (1) GB1288866A (en)
SE (1) SE344287B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105082331B (en) * 2015-08-21 2017-12-05 王荣生 It is a kind of independently of rubber cushion of matrix die body and preparation method thereof

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102011077645A1 (en) 2011-06-16 2012-12-20 Bosch Emission Systems Gmbh & Co. Kg Static mixer

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3354685A (en) * 1964-07-31 1967-11-28 Atomic Energy Authority Uk Hydrostatic extrusion apparatus
US3390563A (en) * 1965-12-09 1968-07-02 Western Electric Co Concentric band high pressure forming chambers
US3513676A (en) * 1967-02-02 1970-05-26 Atomic Energy Authority Uk Hydrostatic extrusion apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3354685A (en) * 1964-07-31 1967-11-28 Atomic Energy Authority Uk Hydrostatic extrusion apparatus
US3390563A (en) * 1965-12-09 1968-07-02 Western Electric Co Concentric band high pressure forming chambers
US3513676A (en) * 1967-02-02 1970-05-26 Atomic Energy Authority Uk Hydrostatic extrusion apparatus

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105082331B (en) * 2015-08-21 2017-12-05 王荣生 It is a kind of independently of rubber cushion of matrix die body and preparation method thereof

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DE2006017A1 (en) 1970-11-19
DE2006017B2 (en) 1981-01-22
JPS5020956B1 (en) 1975-07-18
DE2006017C3 (en) 1981-11-05
SE344287B (en) 1972-04-10
GB1288866A (en) 1972-09-13

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