WO1993014526A1 - Fabrication de supraconducteurs allonges - Google Patents

Fabrication de supraconducteurs allonges Download PDF

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Publication number
WO1993014526A1
WO1993014526A1 PCT/GB1993/000063 GB9300063W WO9314526A1 WO 1993014526 A1 WO1993014526 A1 WO 1993014526A1 GB 9300063 W GB9300063 W GB 9300063W WO 9314526 A1 WO9314526 A1 WO 9314526A1
Authority
WO
WIPO (PCT)
Prior art keywords
axis
rotary forging
elongate
workpiece
reduction steps
Prior art date
Application number
PCT/GB1993/000063
Other languages
English (en)
Inventor
Timothy Paul Beales
Mufti Mohmed Ashraf
Sean Francis Tedstone
Steven Marshall
Original Assignee
Bicc Public Limited Company
Penny & Giles Blackwood Limited
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 Bicc Public Limited Company, Penny & Giles Blackwood Limited filed Critical Bicc Public Limited Company
Priority to BR9305739A priority Critical patent/BR9305739A/pt
Priority to EP93901857A priority patent/EP0621984A1/fr
Priority to AU32638/93A priority patent/AU664588B2/en
Priority to JP5512270A priority patent/JPH07503093A/ja
Publication of WO1993014526A1 publication Critical patent/WO1993014526A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
    • B21J9/00—Forging presses
    • B21J9/02—Special design or construction
    • B21J9/025—Special design or construction with rolling or wobbling dies
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N60/00—Superconducting devices
    • H10N60/01—Manufacture or treatment
    • H10N60/0268—Manufacture or treatment of devices comprising copper oxide
    • H10N60/0801—Manufacture or treatment of filaments or composite wires

Definitions

  • This invention relates to the manufacture of elongate superconductors from particles (especially ceramic particles) that are superconducting or can be made superconducting by an appropriate subsequent treatment. More particularly it relates to the manufacture of superconductors from particles which are plate-like or otherwise anisotropic and which need to be aligned to achieve improved critical-current density.
  • An important application is to the "BiSCCO" range of high- temperature superconducting ceramics of nominal composition M 2 Sr 2 CaCu 2 0g and M 2 Sr 2 Ca 2 Cu 3 0, Q (where M is either Bi or Bi partly substituted by Pb) .
  • the simplest and potentially most satisfactory way of producing an elongate superconductor from superconducting particles is to fill a metal tube (in the case of ceramic particles usually of silver, because many other metals have a deleterious effect on superconducting properties of the particles and few other metals are sufficiently permeable to oxygen to allow the heat-treatment steps that are normally required after reduction) with particulate material and reduce the cross-section of the filled tube to compact the particles and lengthen the assembly.
  • a metal tube in the case of ceramic particles usually of silver, because many other metals have a deleterious effect on superconducting properties of the particles and few other metals are sufficiently permeable to oxygen to allow the heat-treatment steps that are normally required after reduction
  • draw and swaging processes of the kind used to reduce the cross-section of metal rods or the filled-tube preforms for mineral-insulated electric cables produce only a small degree of alignment.
  • Substantially increased alignment can be achieved by first reducing by drawing or swaging sufficiently to form a compact body without substantial voids and then further reducing by a series of rolling steps (with intermediate annealing as required) to produce a superconductor in tape form.
  • a tape thickness below 50 micrometres is currently 5 recommended and is capable of achieving critical current densities (J 's) with good-quality BiSCCO materials in the region of lOG c Am.-2, but it has been established (by experiments using reducing techniques that are applicable only to short specimens) that better alignment could improve
  • a process for the manufacture of an elongate superconductor comprises enclosing anisotropic particles that are superconducting or 5 are capable of being converted to a superconducting form by subsequent treatment in a tube of a ductile metal, compacting it and reducing it in one or more reduction steps to an elongate tape and is characterized by the fact that at least one of the said reduction steps is effected by a rotary 0 forging operation.
  • Rotary forging is a specialised but well-established metalworking technique using two platens which are urged together to engage a workpiece while rotating relative to one another simultaneously about two axes that make a small angle to each other.
  • the angular velocities of rotation about the two axes, the force urging them together and the shapes of*. the platens are selected to produce a rotating localized zone of plastic deformation where neither platen slips on the surface of the work.
  • the one most appropriate for use in the present invention is the one in which one of the platens (usually the lower one and hereinafter referred to as the anvil) is stationary at least in a rotational sense while the movable platen spins about a first axis that is inclined at a small angle ( alpha ) to the direction of the urging force while the first axis rotates about a second axis that is substantially coincident with the direction of the urging force to produce "wobble".
  • Alpha will normally be less than 15° and a convenient geometry uses a flat anvil and a moving platen that is conical with a semi-angle close to the value 90° minus alpha and a cone axis coinciding with the first rotation axis.
  • rotary forging is used for all the reduction steps except possibly for initial compacting.
  • Heat-treatment steps may be used between and/or after reduction steps as required to obtain required properties in the metal and/or the superconducting material.
  • the, or each, rotary forging operation would be continuous with the workpiece continuously advancing through the working zone between the platens. This is unlikely to be feasible, in view of the large forces acting on the workpiece during reduction, and an incremental operation may be adopted in which the platens disengage from the workpiece for part of their rotational cycle or the force urging the platens together is repeatedly withdrawn or reduced to allow the workpiece to be advanced a distance short compared with the length of the working zone; it may be possible (in either case) to achieve quasi-continuous operation by continuously applying a biassing force to the workpiece by pulling from downstream, pushing from upstream, or both.
  • the anvil has a guide groove in its working surface extending inwardly of the latter from an edge of such working surface which is disposed at the inlet side
  • the guide groove has a depth over a portion of its length adjacent the inlet side of the machine which is greater than the corresponding dimension of the workpiece.
  • the guide groove may extend diametrically relative to the cone axis, or there maybe one or more guide grooves which are
  • the invention includes an elongate BiSCCO superconductor with a critical current density in the range
  • Fig. 1 is an axial section through a rotary forging machine suitable for use in the present invention.
  • Fig. 2 is cross-section showing a detail of the o machine of Fig. 1,
  • Fig. 3(i) is a schematic view illustrating the mutual arrangement of first and second die members of the machine in a workpiece feeding condition.
  • Fig. 3(ii) is a schematic illustration showing the 5 mutual arrangement of the die members of the machine in a rotary forging position.
  • Fig. 4(i) is a plan view of one of the die members of the machine of Fig. 1,
  • Fig. 4(ii) is a plan view similar to Fig. 4(i) of a 0 modified machine
  • Fig. 5 is a schematic view of a roll drive and synchronizing arrangement.
  • This example used BiSCCO superconductive particles having the composition Bi l ⁇ 84 Pb 0 ⁇ 3 4 Sr 1#g ⁇ Ca 2 _ 03 Cu 3#06 O y (where y was not determined but can be assumed to be fractionally over 10) and a nominal particle size (d j - n ) estimated by a light-scattering technique as 5 micrometres. These particles were packed into a pure silver tube 150 mm long and with internal and external diameters of 4.0 and 6.0 mm respectively. The open end of the tube was sealed with a force-fitted silver plug, the seal swaged and the assembly drawn through a conventional series of tube-forming dies to a diameter of 0.6 mm.
  • the rotary forging machine has a machine frame 10 comprising a bed 12, four vertical columns 14 (only two are visible) fixed to the bed 12 and extending vertically upwardly therefrom, and an upper crosshead 16 in which the vertical columns 14 are secured.
  • the columns 14 are equi-spaced around the central vertical axis of the machine.
  • a slide 18 has four sleeves 20 which are slidably mounted on the respective columns 14. The slide 18 is therefore fixed against rotation relative to the machine frame 10 but is displaceable vertically relative thereto.
  • the machine further comprises a horizontally disposed rotary screw 22 carrying a pair of oppositely threaded captive nuts 24.
  • Each nut 24 is pivotally connected to the lower end of the respective link 26 whose upper end is pivotally connected to the slide 18 through the intermediary of a belleville washer 27 (a spring plate capable of withstanding high loads).
  • a belleville washer 27 a spring plate capable of withstanding high loads.
  • the slide 18 carries a first platen (the anvil) 28 having a planar upper working surface 30.
  • the anvil 28 is displaceable upon rotation of the screw 22 along a vertical displacement axis indicated by dotted line 32 in Fig. 1, but is fixed against rotation relative to the machine frame 10.
  • This axis 32 coincides with the central axis of the machine.
  • the upper working surface 30 of the anvil 28 has a guide groove 34 therein which extends diametrically across the anvil 28 so as to intersect the displacement axis 32.
  • the guide groove 34 extends perpendicularly to the plane of the axial section of Fig. 1 from an inlet side 36 of the machine to an outlet side 38 thereof.
  • the depth of the guide groove 34 decreases progressively from the inlet side 36 to a location which is about 7/8ths across the diameter of the anvil 28 from the inlet side 36.
  • the inclination of the guide groove 34 and the depth thereof are chosen such that its depth at the centre of the anvil 28 (i.e, at the displacement axis 32) is marginally greater than the diameter of the superconductor precursor workpiece W to be forged. Therefore, it will be appreciated that, when the workpiece W is fed into the rotary forging machine along the base of the guide groove 34, it will only project above the planar upper working surface 30 of the anvil 28 over the region thereof which is disposed on the opposite side of the displacement axis 32 to the inlet side 36.
  • the effective working region of the machine is constituted by the region towards the outlet side 38 of the machine.
  • the width of the guide groove 34 is substantially constant over the whole of the length thereof which is disposed between the inlet side 36 and the displacement axis 32, such width being marginally greater than the diameter of the workpiece W.
  • the width of the groove 34 progressively increases up to the location which is 7/8ths across the diameter of the die member 28 and is then constant up to the outlet side 38. Over the last l/7th of the diameter, the depth of the groove 34 is very small.
  • the rotary forging machine further comprises a second platen 40 mounted on a sleeve 42 rotatably mounted through upper and lower bearings 44 and 46 on a shaft 48 arranged on axis 50 which is disposed at an angle alpha relative to the displacement axis 32 and which is pivotabley about a horizontal axis at a point 51 at which the axes 32 and 50 intersect.
  • the second platen 40 is freely rotatable about axis 50.
  • the shaft 48 is arranged to be driven by a precession drive which is indicated generally by arrow 52 and which includes a vertical drive shaft 54 mounted in upper and lower bearings 56 and 58 carried by the crosshead 16.
  • the vertical drive shaft 54 is rotatable about a vertical axis which is coincident with the displacement axis 32.
  • the lower end of the vertical drive shaft 54 is of rectangular shape (as will be apparent from Fig. 2), is concavely curved over the arc centred on intersection point 51, and has a slot 54b therein extending diametrically relative to the axis of rotation of the shaft 54.
  • the slot 54b has a concavely curved based 54c which is parallel to the lower end face 54a.
  • Upper end region 48a of the shaft 48 is a close sliding fit within the slot 54b.
  • the end region 48a has a convexly curved end face 48b which mates with the base 54c of the slot 54b.
  • the shaft 48 also includes a pair of convexly curved shoulders 48c which mate with respective portions of the lower end face 54a on opposite slides of the slot 54b.
  • the end region 48a has an internally screw-threaded hole 48d extending therethrough diametrically with respect to the axis 50 and longitudinally with respect to the slot 54b.
  • a screw-threaded rod 62 is engaged in the hole 48d and passes with clearance through respective holes in a pair of U-shaped locating members 64 which embrace the shaft 54 at opposite ends of the slot 54.
  • Inner and outer tapered shims 66a and 66b and a nut 68 are engaged with each end region of the rod 62 outwardly of each locating member 64 serve to lock the rod 62 at the desired angle relative to the longitudinal axis of drive shaft 54.
  • the shims 66a and 66b of each pair are relatively rotatable and can be appropriately set to take up the misalignment between the nut 68 and the associated collar 64 caused by the angular offset of the axis of the rod 62.
  • the axes 32 and 50 mutually intersect at point 51 which is at the centre of working surface 76 of the platen 40.
  • the working surface 76 is of downwardly tapering conical shape with a cone angle equal to 180° minus alpha .
  • the horizontal pivot axis 51 intersects the apex of the conical working surface 76.
  • alpha is 5°, but can be adjusted before a rotary forging operation by replacing the die member 40 with one having the desired cone angle, and re-setting by loosening at least one of the nuts 68, rotating rod 62 within the hole 48d to adjust the angle alpha to the appropriate value and then tightening the nuts 68.
  • the rotary forging machine further comprises workpiece-moving means in the form of a pair of haul-off rolls 80 which pull on the rotary forged wire emerging from the outlet side 38 of the machine.
  • the rolls 80 are driven by a stepping motor 82 under the control of a control unit 84 to which an angular position sensor 8 is connected.
  • the angular position sensor 86 is disposed adjacent the drive shaft 54 which itself is driven by motor 90.
  • the rolls 80 are controlled so that they operate to advance the workpiece W in stepwise fashion between the working surfaces 30 and 76 of the die members 28 and 40 in synchronism with precession of the die member 40 about displacement axis 32.
  • the die member 40 is in a position in which it is not in contact with the workpiece W since that region of the working surface 76 which is in contact with the working surface 30 overlies the relatively deep region of the groove 34 at the inlet side 36 of the machine.
  • the stepping motor 82 advances the workpiece W a short distance. In this embodiment, such distance corresponds to approximately 25% of the radius of the die member 28.
  • the platen 40 During movement of the platen 40 relative to the anvil 28, the latter is held in position without rotation of the screw 22.
  • the belleville washer 27 imparts a small degree of resilience in the direction of axis 32 but is sufficiently stiff to permit useful work to be performed on the workpiece W during each forging pass.
  • the compression of the washer 27 can be altered by appropriate adjustment of the screw 22.
  • the forging pressure may remain substantially constant up to a pre-set value.
  • the screw 22 may be adjusted automatically during a rotary forging operation so as to vary the forging pressure for the purpose of optimising the properties of the product being forged.
  • the upper working surface 30 of the anvil 28 has a pair of guide grooves 34 therein.
  • the guide grooves 34 in this embodiment, are mutually parallel and extend across the anvil 28 from the inlet side 36 to the outlet side 38 with at positions spaced from the axis 32.
  • the product of the examples was a flat superconductor with a thickness (including the silver cladding) of 0.1 mm and a width of about 4 mm, and after heat-treatment for 50 hours at 848°C

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Forging (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)

Abstract

On réalise un supraconducteur allongé en enfermant des particules anisotropes supraconductrices ou susceptibles d'être converties en une forme supraconductrice par un traitement subséquent dans un tube en un métal malléable, en compactant ledit tube et en le réduisant en une ou plusieurs étapes de réduction en une bande allongée. Au moins une de ces étapes de réduction est réalisée par un processus de laminage rotatif, de préférence avec un équipement dans lequel un des plateaux est stationnaire du moins en rotation alors que le plateau mobile pivote autour d'un premier axe qui est incliné d'un petit angle alpha par rapport à la direction de la force appliquée, et que le premier axe tourne autour d'un second axe coïncidant sensiblement avec la direction de la force appliquée, pour produire un mouvement 'vacillant'. L'opération de laminage rotatif peut s'effectuer progressivement et par étapes ou être quasi continue. On obtient un alignement sensiblement amélioré des particules supraconductrices en forme de plaques si l'on compare avec les processus de laminage conventionnels, et il en résulte une densité augmentée de courant critique.
PCT/GB1993/000063 1992-01-15 1993-01-13 Fabrication de supraconducteurs allonges WO1993014526A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BR9305739A BR9305739A (pt) 1992-01-15 1993-01-13 Fabricaçao de supercondutores alongadas
EP93901857A EP0621984A1 (fr) 1992-01-15 1993-01-13 Fabrication de supraconducteurs allonges
AU32638/93A AU664588B2 (en) 1992-01-15 1993-01-13 Manufacture of elongate superconductors
JP5512270A JPH07503093A (ja) 1992-01-15 1993-01-13 細長い超電導体の製造

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB929200790A GB9200790D0 (en) 1992-01-15 1992-01-15 Manufacture of elongate superconductors
GB9200790.5 1992-01-15
CN93101743.2A CN1091545A (zh) 1992-01-15 1993-02-15 细长超导体的制造

Publications (1)

Publication Number Publication Date
WO1993014526A1 true WO1993014526A1 (fr) 1993-07-22

Family

ID=36808686

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1993/000063 WO1993014526A1 (fr) 1992-01-15 1993-01-13 Fabrication de supraconducteurs allonges

Country Status (7)

Country Link
EP (1) EP0621984A1 (fr)
JP (1) JPH07503093A (fr)
CN (1) CN1091545A (fr)
AU (1) AU664588B2 (fr)
BR (1) BR9305739A (fr)
GB (1) GB9200790D0 (fr)
WO (1) WO1993014526A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995013627A1 (fr) * 1993-11-12 1995-05-18 Nkt Research Center A/S Procede de production de bandes supraconductrices a densite de courant eleve

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU709214B2 (en) * 1995-05-19 1999-08-26 American Superconductor Corporation A multifilamentary superconducting composite and method of manufacture

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0301279A1 (fr) * 1987-07-28 1989-02-01 BBC Brown Boveri AG Conducteur en matériau composite
EP0397943A1 (fr) * 1989-05-19 1990-11-22 Fujikura Ltd. Méthode de fabrication d'un câble et d'un fil supraconducteurs d'oxyde
EP0435051A2 (fr) * 1989-12-23 1991-07-03 Battelle-Institut e.V. Méthode pour la fabrication de brins supraconducteurs à haute température à fort courant critique et leur application pour faire des dispositifs supraconducteurs
EP0475466A2 (fr) * 1987-02-05 1992-03-18 Sumitomo Electric Industries Limited Procédé pour la fabrication d'un article allongé supraconducteur à base d'une céramique du type oxyde composé

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0475466A2 (fr) * 1987-02-05 1992-03-18 Sumitomo Electric Industries Limited Procédé pour la fabrication d'un article allongé supraconducteur à base d'une céramique du type oxyde composé
EP0301279A1 (fr) * 1987-07-28 1989-02-01 BBC Brown Boveri AG Conducteur en matériau composite
EP0397943A1 (fr) * 1989-05-19 1990-11-22 Fujikura Ltd. Méthode de fabrication d'un câble et d'un fil supraconducteurs d'oxyde
EP0435051A2 (fr) * 1989-12-23 1991-07-03 Battelle-Institut e.V. Méthode pour la fabrication de brins supraconducteurs à haute température à fort courant critique et leur application pour faire des dispositifs supraconducteurs

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
IEEE TRANSACTIONS ON MAGNETICS vol. 27, no. 2, March 1991, NEW YORK, US pages 1239 - 1246 Tenbrink J. et al 'Development of High-Tc Superconductor wires for magnet application' *
IEEE TRANSACTIONS ON MAGNETICS vol. 27, no. 2, March 1991, NEW YORK, US pages 1258 - 1263 Fl}kiger R. et al 'Critical currents in Ag sheated tapes of the 2223-phase in (Bi,Pb)-Sr-Ca-Cu-O' *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995013627A1 (fr) * 1993-11-12 1995-05-18 Nkt Research Center A/S Procede de production de bandes supraconductrices a densite de courant eleve
US6182351B1 (en) 1993-11-12 2001-02-06 Nkt Research Center A/S Method of producing superconducting tapes with a high current density

Also Published As

Publication number Publication date
GB9200790D0 (en) 1992-03-11
JPH07503093A (ja) 1995-03-30
EP0621984A1 (fr) 1994-11-02
BR9305739A (pt) 1997-01-28
AU664588B2 (en) 1995-11-23
CN1091545A (zh) 1994-08-31
AU3263893A (en) 1993-08-03

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