Welding - Micro joining of 2nd generation high temperature superconductors - Part 1: General requirements for the procedure (ISO 17279-1:2018)

This document provides concepts, specification and qualification of 2G HTS joining procedure. A welding procedure specification (WPS) is needed to provide a basis for planning joining operations and for quality control during joining. Joining is considered as a special process in the terminology of standards for quality systems. Standards for quality systems usually require that special processes be carried out in accordance with written procedure specifications. This has resulted in the establishment of a set of rules for qualification of the joining procedure prior to the release of the WPS to actual production. This document defines these rules.
This document does not cover soldering, brazing or any fillers, which are currently available in the industry. It can be applied for joining of all kinds of 2G HTSs.
This document does not apply to 1st Generation Bismuth Strontium Calcium Copper Oxide (1G BSCCO) type HTS and Low Temperature Superconductor (LTS) Joining.

Schweißen - Mikrofügen von Hochtemperatursupraleitern der zweiten Generation - Teil 1: Allgemeine Anforderungen an das Verfahren (ISO 17279-1:2018)

Dieses Dokument enthält Konzepte, Spezifikationen und Qualifizierungen für das Verfahren zur Fügung von 2G HTS. Eine Schweißanweisung (en: welding procedure specification, WPS) wird als Basis für die Planung von Fügeprozessen und zur Qualitätskontrolle während des Fügens benötigt. Das Fügen wird als spezieller Prozess im Rahmen der Terminologie von Normen für Qualitätssysteme erachtet. Normen für Qualitätssysteme erfordern üblicherweise die Ausführung von speziellen Prozessen in Übereinstimmung mit den schriftlichen Verfahrensspezifikationen. Dies führte zur Aufstellung eines Regelwerks zur Qualifizierung von Fügeverfahren vor der Herausgabe einer WPS in die tatsächliche Produktion. Dieses Dokument legt diese Regeln fest.
Dieses Dokument deckt nicht die Verfahren zum Weichlöten, Hartlöten oder Füllen ab, die momentan in der Industrie verfügbar sind. Es kann auf das Fügen aller Arten von 2G HTS angewandt werden.
Dieses Dokument betrifft nicht das Fügen von Hochtemperatur-Supraleitern der ersten Generation (Bismut Strontium Calcium Kupferoxid oder 1G BSCCO), sowie Tieftemperatur Supraleitern (LTS).

Soudage - Micro-assemblage des supraconducteurs à haute température de deuxième génération - Partie 1: Exigences générales pour la procédure (ISO 17279-1:2018)

Le présent document fournit les concepts, le descriptif et la qualification d'un mode opératoire d'assemblage des supraconducteurs à haute température de deuxième génération (2G HTS). Un descriptif de mode opératoire de soudage (DMOS) est requis afin de servir de base à la planification des opérations d'assemblage et aux contrôles qualité pendant l'assemblage. L'assemblage est traité comme un procédé à part dans la terminologie des normes relatives aux systèmes qualité. Les normes de systèmes qualité exigent généralement d'exécuter les procédés spéciaux conformément à des descriptifs de mode opératoire écrits. Il est donc nécessaire d'établir un ensemble de règles de qualification de mode opératoire d'assemblage avant toute publication de DMOS en production réelle. Le présent document définit ces règles.
Le présent document ne concerne pas les procédés de brasage fort ou tendre ou d'apport de matériaux existant à ce jour dans l'industrie. Le présent document peut s'appliquer aux assemblages de toutes sortes de supraconducteurs à haute température de deuxième génération (2G HTS).
Le présent document ne s'applique pas aux assemblages de supraconducteurs à haute température (HTS) à base d'oxydes de bismuth, de strontium, de calcium et de cuivre de première génération (1G BSCCO) ni aux assemblages de supraconducteurs à basse température (LTS).

Varjenje - Mikro spajanje visokotemperaturnih superprevodnikov druge generacije - 1. del: Splošne zahteve za postopek (ISO 17279-1:2018)

Ta mednarodni standard določa izraze in definicije, specifikacije in kvalifikacije za postopek spajanja visokotemperaturnih superprevodnikov druge generacije. Specifikacija varilnega postopka (WPS) je potrebna kot podlaga za načrtovanje postopka spajanja in nadzor kakovosti med spajanjem. Spajanje se v terminologiji standardov za sisteme kakovosti obravnava kot poseben postopek. V standardih za sisteme kakovosti je običajno navedena zahteva, da se posebni postopki izvedejo v skladu s pisnimi specifikacijami za postopek. Posledično je bila določena zbirka pravil za kvalifikacijo spajanja pred izdajo specifikacije varilnega postopka v dejansko proizvodnjo. Ta del standarda ISO 17279 določa ta pravila.
Ta standard ne zajema mehkega spajkanja, trdega spajkanja ali polnil, ki so trenutno na voljo v industriji.
Ta mednarodni standard je mogoče uporabiti za spajanje vseh vrst visokotemperaturnih superprevodnikov druge generacije. Ta standard se ne uporablja za spajanje prve generacije visokotemperaturnih superprevodnikov BSCCO (bizmutov, stroncijev, kalcijev, bakrov oksid) in nizkotemperaturnega superprevodnika (LTS).

General Information

Status
Published
Publication Date
06-Nov-2018
Technical Committee
Drafting Committee
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
07-Nov-2018
Completion Date
07-Nov-2018

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SLOVENSKI STANDARD
SIST EN ISO 17279-1:2019
01-marec-2019
Varjenje - Mikro spajanje visokotemperaturnih superprevodnikov druge generacije
- 1. del: Splošne zahteve za postopek (ISO 17279-1:2018)

Welding - Micro joining of 2nd generation high temperature superconductors - Part 1:

General requirements for the procedure (ISO 17279-1:2018)

Schweißen - Mikrofügen von Hochtemperatursupraleitern der zweiten Generation - Teil

1: Allgemeine Anforderungen an das Verfahren (ISO 17279-1:2018)
Soudage - Micro-assemblage des supraconducteurs à haute température de deuxième
génération - Partie 1: Exigences générales pour la procédure (ISO 17279-1:2018)
Ta slovenski standard je istoveten z: EN ISO 17279-1:2018
ICS:
25.160.10 Varilni postopki in varjenje Welding processes
29.050 Superprevodnost in prevodni Superconductivity and
materiali conducting materials
SIST EN ISO 17279-1:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 17279-1:2019
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SIST EN ISO 17279-1:2019
EN ISO 17279-1
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2018
EUROPÄISCHE NORM
ICS 25.160.01
English Version
Welding - Micro joining of 2nd generation high
temperature superconductors - Part 1: General
requirements for the procedure (ISO 17279-1:2018)
Soudage - Micro-assemblage des supraconducteurs à Schweißen - Mikrofügen von

haute température de deuxième génération - Partie 1: Hochtemperatursupraleitern der zweiten Generation -

Exigences générales pour la procédure (ISO 17279- Teil 1: Allgemeine Anforderungen an das Verfahren

1:2018) (ISO 17279-1:2018)
This European Standard was approved by CEN on 30 September 2018.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this

European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references

concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN

member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by

translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management

Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 17279-1:2018 E

worldwide for CEN national Members.
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SIST EN ISO 17279-1:2019
EN ISO 17279-1:2018 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 17279-1:2019
EN ISO 17279-1:2018 (E)
European foreword

This document (EN ISO 17279-1:2018) has been prepared by Technical Committee ISO/TC 44 "Welding

and allied processes" in collaboration with Technical Committee CEN/TC 121 “Welding and allied

processes” the secretariat of which is held by DIN.

This European Standard shall be given the status of a national standard, either by publication of an

identical text or by endorsement, at the latest by May 2019, and conflicting national standards shall be

withdrawn at the latest by May 2019.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the

following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,

Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
Endorsement notice

The text of ISO 17279-1:2018 has been approved by CEN as EN ISO 17279-1:2018 without any

modification.
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SIST EN ISO 17279-1:2019
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SIST EN ISO 17279-1:2019
INTERNATIONAL ISO
STANDARD 17279-1
First edition
2018-09
Welding — Micro joining of 2nd
generation high temperature
superconductors —
Part 1:
General requirements for the
procedure
Soudage — Micro-assemblage des supraconducteurs à haute
température de 2ème génération —
Partie 1: Exigences générales pour la procédure
Reference number
ISO 17279-1:2018(E)
ISO 2018
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SIST EN ISO 17279-1:2019
ISO 17279-1:2018(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2018

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved
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SIST EN ISO 17279-1:2019
ISO 17279-1:2018(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Symbols and abbreviated terms ........................................................................................................................................................... 2

5 Requirements .......................................................................................................................................................................................................... 2

5.1 Joint design ................................................................................................................................................................................................. 2

5.1.1 General...................................................................................................................................................................................... 2

5.1.2 Lap joint ................................................................................................................................................................................... 3

5.1.3 Bridge joint ........................................................................................................................................................................... 3

5.2 Equipment ................................................................................................................................................................................................... 4

5.3 Welding procedure qualification ............................................................................................................................................. 5

5.4 Micro-joining and oxygenation-annealing process ................................................................................................. 5

5.4.1 General...................................................................................................................................................................................... 5

5.4.2 Technical content of a pWPS and WPS .......................................................................................................... 8

5.5 Qualification based on standard test joint specimen ............................................................................................. 9

5.5.1 General...................................................................................................................................................................................... 9

5.5.2 Test specimens................................................................................................................................................................... 9

5.5.3 Micro-joining and oxygenation-annealing procedure of test specimens ........................ 9

5.5.4 Testing of test specimens .................. .....................................................................................................................13

5.5.5 Re-testing ............................................................................................................................................................................16

5.5.6 Test record ...................................................................... ....................................................................................................16

5.6 Range of qualification ....................................................................................................................................................................16

5.6.1 General...................................................................................................................................................................................16

5.6.2 Related to the manufacturer ...............................................................................................................................16

5.6.3 Essential variables .......................................................................................................................................................16

5.6.4 Other variables ...............................................................................................................................................................17

5.7 Micro-joining and oxygenation-annealing procedure specification and procedure

qualification record ..........................................................................................................................................................................17

5.8 Final treatment of production run joints ......................................................................................................................17

5.9 Acceptance criteria ...........................................................................................................................................................................18

5.10 Identification and traceability ................................................................................................................................................19

6 Third-party check .............................................................................................................................................................................................19

Annex A (informative) Micro-joining and oxygenation-annealing procedure .......................................................20

Annex B (informative) Preliminary Welding Procedure Specification (pWPS) ....................................................24

Annex C (informative) Procedure qualification for micro-joining and oxygenation

annealing and Welding Procedure Qualification Record (WPQR) .................................................................27

Annex D (informative) Welding Procedure Specification (WPS) .........................................................................................33

Annex E (informative) Check list for micro-joining and oxygenation-annealing procedure

qualification ...........................................................................................................................................................................................................36

Bibliography .............................................................................................................................................................................................................................39

© ISO 2018 – All rights reserved iii
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SIST EN ISO 17279-1:2019
ISO 17279-1:2018(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso

.org/iso/foreword .html.

This document was prepared by Technical Committee ISO/TC 44, Welding and allied processes,

Subcommittee SC 10, Quality management in the field of welding.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/members .html.
A list of all parts in the ISO 17279 series can be found on the ISO website.
iv © ISO 2018 – All rights reserved
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SIST EN ISO 17279-1:2019
ISO 17279-1:2018(E)
Introduction

The increasing use of 2nd generation high temperature superconductors (2G HTSs) and invention of

resistance-free joining on 2G HTSs have created the need for this document in order to ensure that

joining is carried out in the most effective way and that appropriate control is exercized over all aspects

of the operation. ISO standards for micro-joining and joint evaluation procedure are accordingly

essential to get the best and uniform quality of 2G HTS joint.

The technique in this document regarding resistance-free micro-joining is patent-registered and was

reported to patent.statements@iso .org using the “Patent Statement and Licensing Declaration Form”.

A superconductor is a material that conducts electricity without resistance and has diamagnetism below

critical temperature, T, critical magnetic field, B , and critical current density, J . Once set in motion,

c c

electrical current flows forever in a closed loop of superconducting material under diamagnetism.

A 2G HTS consists of multi-layers and its total thickness is around between 60 µm and 100 µm with or

without surrounding copper stabilizer. The superconducting layer made from ReBa Cu O -x (ReBCO,

2 3 7

abbreviated term of ReBa Cu O ) is only between 1 µm and 2 µm thick depending on manufacturer’s

2 3 7-x

specifications. Re stands for Rare Earth materials, of which gadolinium, yttrium and samarium are used

for 2nd generation high temperature superconducting materials. Figure 1 shows schematic drawing of

typical multiple layers with surrounded copper stabilizer, and the constituents and thicknesses of each

layer in the 2G HTS. The two layers of No. 1 in Figure 1 does not exist in stabilizer-free 2G HTS.

Key
1 20 µm Cu stabilizer 4 5 buffing layers (total 160 nm)
2 2 µm Ag overlayer 5 50 µm hastelloy substrate
3 between 1 µm and 2 µm ReBCO super-conducting
layer
NOTE Not to scale.

Figure 1 — Typical 2G HTS multi-layers, and the constituents and thicknesses of each layer

Currently soldering, brazing or any filler is applied in superconducting industry as shown in Figure 2,

which shows high electrical resistance at the joint providing fatal flaw in the superconductor.

© ISO 2018 – All rights reserved v
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SIST EN ISO 17279-1:2019
ISO 17279-1:2018(E)
a) Lap joint b) Bridge joint
Key
1 superconducting layer
2 solder
Figure 2 — Soldering to join 2G HTS

However, this document focuses on the direct autogenous joining of between 1 μm and 2 μm-

thick superconducting layers of 2G HTSs as shown in Figure 3 without filler metals and recovery of

superconducting properties by oxygenation annealing process, which shows almost no electrical

resistance at the joint.
a) Lap joint b) Bridge joint
Key
1 superconducting layer

Figure 3 — Direct autogenous joining of two superconducting layers of 2G HTSs for

superconducting joint
vi © ISO 2018 – All rights reserved
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SIST EN ISO 17279-1:2019
ISO 17279-1:2018(E)

The International Organization for Standardization (ISO) draws attention to the fact that it is claimed

that compliance with this document may involve the use of patents concerning 2G HTS resistance-

free joining. ISO takes no position concerning the evidence, validity and scope of this patent right.

The holders of these patent rights have assured ISO that they are willing to negotiate licenses under

reasonable and non-discriminatory terms and conditions with applicants throughout the world. In this

respect, the statement of the holders of these patent rights is registered with ISO. Information may be

obtained from:
KJoins, Inc. Dae-A International IP & Law Firm
913C, H-1, KIST Venture Town 3F Hanyang B/D
Korea Institute of Science and Technology 830-71 Yeoksam dong, Gangnam gu
14-1 Hwarang ro, Seongbuk gu SEOUL 135–936
SEOUL 136–791 REP. OF KOREA
REP. OF KOREA
Tel.: +82 2 565 2500
Tel.: +82 2 921 6966
Fax: +82 2 565 2511
Contact: Dr HeeSung ANN
Contact: Patent Attorney Mr. BoHyun KIM
E-mail: andy@kjoins .com
E-mail: bohkim@ipdraju .com
Contact: Dr YoungKun OH
Email: ykoh@kjoins .com
Contact: Dr MyungWhon LEE
E-mail: mwlee@kjoins .com

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights other than those identified above. ISO shall not be held responsible for identifying any or

all such patents.
© ISO 2018 – All rights reserved vii
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SIST EN ISO 17279-1:2019
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SIST EN ISO 17279-1:2019
INTERNATIONAL STANDARD ISO 17279-1:2018(E)
Welding — Micro joining of 2nd generation high
temperature superconductors —
Part 1:
General requirements for the procedure
1 Scope

This document provides concepts, specification and qualification of 2G HTS joining procedure. A

welding procedure specification (WPS) is needed to provide a basis for planning joining operations

and for quality control during joining. Joining is considered as a special process in the terminology of

standards for quality systems. Standards for quality systems usually require that special processes be

carried out in accordance with written procedure specifications. This has resulted in the establishment

of a set of rules for qualification of the joining procedure prior to the release of the WPS to actual

production. This document defines these rules.

This document does not cover soldering, brazing or any fillers, which are currently available in the

industry. It can be applied for joining of all kinds of 2G HTSs.

This document does not apply to 1st Generation Bismuth Strontium Calcium Copper Oxide (1G BSCCO)

type HTS and Low Temperature Superconductor (LTS) Joining.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 15607:2003, Specification and qualification of welding procedures for metallic materials — General rules

ISO 17279-2, Welding — Micro-joining of 2nd generation high temperature superconductors — Part 2:

Personnel qualification for micro-joining and testing
ISO/TR 25901 (all parts), Welding and related processes — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/TR 25901 and the

following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
high temperature superconductor
HTS

superconducting material with critical temperature higher than liquid nitrogen boiling point

© ISO 2018 – All rights reserved 1
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SIST EN ISO 17279-1:2019
ISO 17279-1:2018(E)
3.2
low temperature superconductor
LTS

superconducting material with critical temperature lower than liquid nitrogen boiling point

3.3
2nd generation high temperature superconductor
2G HTS

superconducting material with critical temperature higher than liquid nitrogen boiling point, made of

rare earth and other elements like barium, copper and their oxides

Note 1 to entry: A first generation high temperature superconductor (1G HTS) is a superconducting material with

critical temperature higher than liquid nitrogen boiling point, made of bismuth strontium calcium copper oxides.

3.4
pressurized partial micro-melting diffusion

partial micro-melting of the two faying surfaces of 1 μm- to 3 μm-thick superconducting layers

and atoms diffusion in partially micro-molten pool and solid state of the superconducting layers by

pressurized force
3.5
oxygenation annealing

process to restore the oxygen stoichiometry in an oxygen-rich environment and to recover

superconducting properties

Note 1 to entry: Structure and superconducting properties of 2G HTS are strongly affected by the oxygen

stoichiometry. Joining of 2G HTS at high temperature induces oxygen out-diffusion causing a phase change from a

superconducting orthorhombic phase to a non-superconducting tetragonal phase.
3.6
pressurized solid-state diffusion

atoms diffusion in solid state of the two faying surfaces of 1 μm- to 3 μm-thick superconducting layers

with pressurized force
3.7
bridge joint

joint with a third 2G HTS piece overlapped as a bridge on top of two 2G HTS pieces

Note 1 to entry: See Figure 3 and Figure 5.
4 Symbols and abbreviated terms

The abbreviatied terms listed in ISO 15607:2003, Table 1, relevant to joining procedure for 2G HTS,

shall apply.
5 Requirements
5.1 Joint design
5.1.1 General

The joint shall be designed in accordance with defined requirements that support the end use of the

product. Documentation shall clearly define the essential information of the joint and any special

requirements, e.g. fracture critical, durability critical, mission critical, or safety critical, that are

imposed over and above the general requirements. Essential process controls shall be defined to

substantiate that all design requirements can be met by the joints that were produced in accordance

with welding procedure specification (WPS) and testing and inspection requirements.

2 © ISO 2018 – All rights reserved
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SIST EN ISO 17279-1:2019
ISO 17279-1:2018(E)

The joint design shall take into account the necessary material property data. There are basically two

types of joint alignments (lap and bridge) and the suitable alignment can be selected depending on

user’s convenience. The two types of joint alignments for joining of 2G HTS are shown in Figure 3.

5.1.2 Lap joint

Figure 4 shows schematic sketch of lap joint design for welding procedure qualification as described

in 5.3. All lengths, l , and l , should be specified in the procedure qualification report (PQR). As joint

0 1

length, l , is increased, effective contact surface areas between two superconducting layers are

increased, probabilities of atoms inter-diffusion between the two layers for the joining are increased,

and accordingly joint strengths (tensile and bending) are increased. The Cu stabilizers, if included,

and Ag overlayers on top of the superconducting layers shall be perfectly removed for direct contact of

two superconducting layers and micro-joining. This process is for not contaminating superconducting

layers during micro-joining.
Key
1 superconducting layer
l 60 mm; length of two parts
l 40 mm; overlap (joint length)
Figure 4 — Lap joint
5.1.3 Bridge joint

Figure 5 illustrates the joint design for welding procedure qualification as described in 5.3. The

distance, l , between two 2G HTS parts in Figure 5 may be ranged from "0" to over 10 cm depending

on joint design. The lengths of l in Figure 5 should be the same. All lengths, l , l , l , and l , should

0 0 1 2 3

be specified in the procedure qualification report (PQR). As joint lengths, l , are increased, effective

contact surface areas between two superconducting layers are increased, probabilities of atoms inter-

diffusion between the two layers for the joining are increased, and accordingly joint strengths (tensile

and bending) and superconductivity are increased. The Cu stabilizers, if included, and Ag overlayers on

top of the superconducting layers shall be perfectly removed for direct contact of two superconducting

layers and joining. This process is to avoid contaminating the superconducting layers during joining.

© ISO 2018 – All rights reserved 3
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SIST EN ISO 17279-1:2019
ISO 17279-1:2018(E)
Key
1 superconducting layer
l 50 mm; length of two parts at bottom
l 40 mm to 50 mm; length of bridge part
l 0 mm to 10 mm; distance between parts to join
l 20 mm; overlap (joint length)
Figure 5 — Bridge joint
5.2 Equipment

The equipment shall be adequate for the application concerned. Joining equipment shall be capable

of producing joints that meet the acceptance criteria specified in 5.9. Joining equipment shall be

maintained in good condition and shall be repaired or adjusted when a joining operator, inspector or

joining coordinator is concerned about the capability of the equipment to operate satisfactorily.

After installation of new or refurbished equipment or developing the new equipment, appropriate tests

shall be performed. Such tests shall verify the equipment functions correctly.

Reproducibility tests shall be performed to demonstrate that the joining equipment can repeatedly

produce joints that meet the acceptance levels in 5.9. The reproducibility test shall be performed in

accordance with a WPS that is used in production for that machine. A minimum of three test joins shall be

made and found satisfactory. Reproducibility tests shall be carried out when any of the following occurs:

— critical component(s) of the equipment is (are) damaged, repaired, or replaced;

— equipment is dislodged or moved in a manner for which it was not d
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Questions, Comments and Discussion

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