IEC 60068-2-20:2021

Environmental testing - Part 2-20: Tests - Test Ta and Tb: Test methods for solderability and resistance to soldering heat of devices with leads

IEC 60068-2-20:2021 outlines Tests Ta and Tb, applicable to devices with leads and leads themselves. Soldering tests for surface mounting devices (SMD) are described in IEC 60068-2-58. This document provides procedures for determining the solderability and resistance to soldering heat of devices in applications using solder alloys, which are eutectic or near eutectic tin lead (Pb), or lead-free alloys. The procedures in this document include the solder bath method and soldering iron method. The objective of this document is to ensure that component lead or termination solderability meets the applicable solder joint requirements of IEC 61191-3 and IEC 61191-4. In addition, test methods are provided to ensure that the component body can be resistant to the heat load to which it is exposed during soldering. This edition includes the following significant technical changes with respect to the previous edition:
- update of and clarification of pre-conditioning (former "aging") and its relation to natural aging.

Essais d’environnement - Partie 2-20: Essais - Essais Ta et Tb: Méthodes d'essai de la brasabilité et de la résistance à la chaleur de brasage des dispositifs à broches

L'IEC 60068-2-20:2021 décrit les essais Ta et Tb qui s’appliquent aux dispositifs à broches et aux broches elles-mêmes. Les essais de brasage des composants pour montage en surface (CMS) sont décrits dans l’IEC 60068-2-58. Le présent document fournit des procédures pour déterminer la brasabilité et la résistance à la chaleur de brasage des dispositifs dans les applications qui utilisent des alliages de brasure, qui sont soit des brasures étain plomb (Pb) eutectique ou quasi eutectique, soit des alliages de brasure sans plomb. Les procédures du présent document incluent les méthodes dites de bain de brasage et de fer à braser. Le but du présent document est d’assurer que les broches des composants ou la brasabilité de leurs bornes sont en mesure de satisfaire aux exigences applicables aux joints de brasures de l’IEC 61191-3 et de l’IEC 61191-4. De plus, des méthodes d’essai sont fournies pour assurer que le corps du composant peut résister à la charge calorifique à laquelle il est exposé pendant le brasage. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- mise à jour et clarification du préconditionnement (auparavant "vieillissement") et sa relation au vieillissement naturel.

General Information

• Status: Published
• Publication Date: 29-Mar-2021
• ICS: 19.040 - Environmental testing
• Technical Committee: TC 91 - Electronics assembly technology
• Drafting Committee: WG 3 - TC 91/WG 3
• Current Stage: PPUB - Publication issued
• Start Date: 16-Apr-2021
• Completion Date: 30-Mar-2021

Relations

• Revises: IEC 60068-2-20:2008 - Environmental testing - Part 2-20: Tests - Test T: Test methods for solderability and resistance to soldering heat of devices with leads
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 60068-2-20 ®
Edition 6.0 2021-03
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Environmental testing –
Part 2-20: Tests – Test T Tests Ta and Tb: Test methods for solderability and
resistance to soldering heat of devices with leads

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: [phone]
3, rue de Varembé [e-mail]
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Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

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IEC 60068-2-20 ®
Edition 6.0 2021-03
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Environmental testing –
Part 2-20: Tests – Test T Tests Ta and Tb: Test methods for solderability and

resistance to soldering heat of devices with leads

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 19.040 ISBN 978-2-8322-9661-5

– 2 – IEC 60068-2-20:2021 RLV © IEC 2021
CONTENTS
FOREWORD . 4
1 Scope and object . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Test Ta: Solderability of wire and tag terminations . 8
4.1 Objective and general description of the test . 8
4.1.1 Test methods . 8
4.1.2 Specimen preparation . 9
4.1.3 Initial measurements . 9
4.1.4 Accelerated ageing Preconditioning . 9
4.2 Method 1: Solder bath . 10
4.2.1 General . 10
4.2.2 Description of the solder bath . 10
4.2.3 Flux . 10
4.2.4 Procedure . 10
4.2.5 Test conditions . 11
4.2.6 Final measurements and requirements . 12
4.3 Method 2: Soldering iron at 350 °C . 12
4.3.1 General . 12
4.3.2 Description of soldering irons . 13
4.3.3 Solder and flux . 13
4.3.4 Procedure . 13
4.3.5 Final measurements and requirements . 14
4.4 Information to be given in the relevant specification . 14
5 Test Tb: Resistance to soldering heat . 15
5.1 Objective and general description of the test . 15
5.1.1 Test methods . 15
5.1.2 Initial measurements . 15
5.2 Method 1: Solder bath . 15
5.2.1 Description of the solder bath . 15
5.2.2 Flux . 15
5.2.3 Procedure . 15
5.2.4 Test conditions . 16
5.2.5 De-wetting . 17
5.3 Method 2: Soldering iron . 17
5.3.1 Description of soldering iron . 17
5.3.2 Solder and flux . 17
5.3.3 Procedure . 17
5.4 Recovery . 18
5.5 Final measurements and requirements . 18
5.6 De-wetting (if required) . 18
5.7 Information to be given in the relevant specification . 19
Annex A (informative) Example of apparatus for accelerated steam
ageing conditioning process . 20
Annex B (normative) Specification for flux constituents . 21
B.1 Colophony . 21

B.2 2-propanol (isopropanol isopropyl alcohol) . 21
B.3 Ethyl alcohol . 21
B.4 Flux composition . 21
Bibliography . 23

Figure 1 – Diagram of contact angle . 7
Figure 2 – Position of soldering iron . 14
Figure A.1 – Example of apparatus . 20

Table 1 – Solderability, solder bath method: Test severities (duration and temperature) . 12
Table 2 – Resistance to soldering heat, solder bath method: Test severities (duration
and temperature) . 17
Table B.1 – Colophony based flux compositions . 22

– 4 – IEC 60068-2-20:2021 RLV © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ENVIRONMENTAL TESTING –
Part 2-20: Tests –
Test T Tests Ta and Tb: Test methods for solderability
and resistance to soldering heat of devices with leads

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
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Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
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This redline version of the official IEC Standard allows the user to identify the changes made to
the previous edition IEC 60068-2-20:2008. A vertical bar appears in the margin wherever a change
has been made. Additions are in green text, deletions are in strikethrough red text.

IEC 60068-2-20 has been prepared by IEC technical committee 91: Electronics assembly
technology. It is an International Standard.
This sixth edition cancels and replaces the fifth edition published in 2008. This sixth edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) update of and clarification of pre-conditioning (former "aging") and its relation to natural
aging.
The text of this International Standard is based on the following documents:
Draft Report on voting
91/1701/FDIS 91/1711/RVD
Full information on the voting for its approval can be found in the r
...

IEC 60068-2-20 ®
Edition 6.0 2021-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Environmental testing –
Part 2-20: Tests – Tests Ta and Tb: Test methods for solderability and
resistance to soldering heat of devices with leads

Essais d’environnement –
Partie 2-20: Essais – Essais Ta et Tb: Méthodes d'essai de la brasabilité
et de la résistance à la chaleur de brasage des dispositifs à broches

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC online collection - oc.iec.ch
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containing more than 22 000 terminological entries in English
details all new publications released. Available online and
and French, with equivalent terms in 18 additional languages.
once a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
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need further assistance, please contact the Customer Service
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IEC 60068-2-20 ®
Edition 6.0 2021-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Environmental testing –
Part 2-20: Tests – Tests Ta and Tb: Test methods for solderability and

resistance to soldering heat of devices with leads

Essais d’environnement –
Partie 2-20: Essais – Essais Ta et Tb: Méthodes d'essai de la brasabilité

et de la résistance à la chaleur de brasage des dispositifs à broches

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 19.040 ISBN 978-2-8322-9585-4

– 2 – IEC 60068-2-20:2021 © IEC 2021
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Test Ta: Solderability of wire and tag terminations . 8
4.1 Objective and general description of the test . 8
4.1.1 Test methods . 8
4.1.2 Specimen preparation . 8
4.1.3 Initial measurements . 9
4.1.4 Preconditioning . 9
4.2 Method 1: Solder bath . 10
4.2.1 General . 10
4.2.2 Description of the solder bath . 10
4.2.3 Flux . 10
4.2.4 Procedure . 10
4.2.5 Test conditions . 11
4.2.6 Final measurements and requirements . 11
4.3 Method 2: Soldering iron at 350 °C . 11
4.3.1 General . 11
4.3.2 Description of soldering irons . 11
4.3.3 Solder and flux . 12
4.3.4 Procedure . 12
4.3.5 Final measurements and requirements . 13
4.4 Information to be given in the relevant specification . 13
5 Test Tb: Resistance to soldering heat . 14
5.1 Objective and general description of the test . 14
5.1.1 Test methods . 14
5.1.2 Initial measurements . 14
5.2 Method 1: Solder bath . 14
5.2.1 Description of the solder bath . 14
5.2.2 Flux . 14
5.2.3 Procedure . 14
5.2.4 Test conditions . 15
5.2.5 De-wetting . 15
5.3 Method 2: Soldering iron . 16
5.3.1 Description of soldering iron . 16
5.3.2 Solder and flux . 16
5.3.3 Procedure . 16
5.4 Recovery . 16
5.5 Final measurements and requirements . 16
5.6 De-wetting (if required) . 16
5.7 Information to be given in the relevant specification . 17
Annex A (informative) Example of apparatus for steam conditioning process . 18
Annex B (normative) Specification for flux constituents . 19
B.1 Colophony . 19
B.2 2-propanol (isopropyl alcohol) . 19

B.3 Ethyl alcohol . 19
B.4 Flux composition . 19
Bibliography . 21

Figure 1 – Diagram of contact angle . 7
Figure 2 – Position of soldering iron . 12
Figure A.1 – Example of apparatus . 18

Table 1 – Solderability, solder bath method: Test severities (duration and temperature) . 11
Table 2 – Resistance to soldering heat, solder bath method: Test severities (duration
and temperature) . 15
Table B.1 – Colophony based flux compositions . 20

– 4 – IEC 60068-2-20:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ENVIRONMENTAL TESTING –
Part 2-20: Tests –
Tests Ta and Tb: Test methods for solderability
and resistance to soldering heat of devices with leads

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publi
...