IEC 63522-16:2025

Electrical relays - Tests and measurements - Part 16: Soldering

IEC 63522-16:2025 This part of IEC 63522 is used for testing along with the appropriate severities and conditions for measurements and tests designed to assess the ability of DUTs to perform under expected conditions of transportation, storage and all aspects of operational use.
This document defines a standard test method for resistance to soldering heat and solderability for standard soldering processes.

Relais électriques - Essais et mesurages - Partie 16: Brasage

IEC 63522-16:2025 La présente partie de l'IEC 63522 est utilisée pour réaliser, avec les sévérités et les conditions appropriées aux mesurages et aux essais, les essais destinés à évaluer l'aptitude des DUT à fonctionner dans les conditions prévues de transport et de stockage, ainsi que dans tous les aspects de l'utilisation opérationnelle.
Le présent document définit une méthode d'essai normalisée de la résistance à la chaleur de brasage et de la brasabilité pour les procédés de brasage normalisés.

General Information

• Status: Published
• Publication Date: 21-Apr-2025
• ICS: 29.120.70 - Relays
• Technical Committee: TC 94 - Electrical relays
• Drafting Committee: WG 3 - TC 94/WG 3
• Current Stage: PPUB - Publication issued
• Start Date: 22-Apr-2025
• Completion Date: 07-Mar-2025

Standards Content (Sample)

IEC 63522-16 ®
Edition 1.0 2025-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical relays – Tests and measurements –
Part 16: Soldering
Relais électriques – Essais et mesurages –
Partie 16: Brasage
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IEC 63522-16 ®
Edition 1.0 2025-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrical relays – Tests and measurements –

Part 16: Soldering
Relais électriques – Essais et mesurages –

Partie 16: Brasage
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.120.70  ISBN 978-2-8327-0352-6

– 2 – IEC 63522-16:2025 © IEC 2025
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Test procedure . 6
4.1 Purpose . 6
4.2 Procedure . 6
4.2.1 General. 6
4.2.2 Resistance to soldering heat . 6
4.2.3 Resistance to standard industrial soldering processes . 8
4.2.4 Solderability, wetting – Wetting balanced method . 9
4.3 Conditions . 10
5 Evaluation . 10
5.1 General . 10
5.2 Test report . 11
Bibliography . 12

Figure 1 – Double wave soldering profile . 8
Figure 2 – SMT and through hole soldering profile . 9

Table 1 – Test conditions for test Tb . 7

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL RELAYS – TESTS AND MEASUREMENTS –

Part 16: Soldering
FOREWORD
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IEC 63522-16 have been prepared by IEC technical committee 94: Electrical relays. It is an
International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
94/1071/FDIS 94/1120/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.

– 4 – IEC 63522-16:2025 © IEC 2025
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts of IEC 63522 series, published under the general title Electrical relays – Tests
and measurements, can be found on the IEC website.
This International Standard is to be used in conjunction with IEC 63522-0:– .
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
___________
Under preparation. Stage at the time of publication: IEC CDV 63522-0:2024.

ELECTRICAL RELAYS – TESTS AND MEASUREMENTS –

Part 16: Soldering
1 Scope
This part of IEC 63522 is used for testing along with the appropriate severities and conditions
for measurements and tests designed to assess the ability of DUTs to perform under expected
conditions of transportation, storage and all aspects of operational use.
This document defines a standard test method for resistance to soldering heat and solderability
for standard soldering processes.
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.
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 60068-2-69, Environmental testing – Part 2-69: Tests – Test Te/Tc: Solderability testing of
electronic components and printed boards by the wetting balance (force measurement) method
IEC 61760-1:2020, Surface mounting technology – Part 1: Standard method for the
specification of surface mounting components (SMDs)
IEC 63522-0:─ , Electrical relays – Tests and measurements – Part 0: General and guidance
IEC 63522-1:– , Electrical relays – Tests and measurements - Part 1: Visual inspection and
check of dimensions
IEC 63522-7:– , Electrical relays – Tests and measurements – Part 7: Functional tests
IEC 63522-11:2025, Electrical relays – Tests and measurements – Part 11: Enclosure
protection and degree of protection
3 Terms and definitions
For the purposes of this document, the terms and definitions given in Clause 3 of IEC 63522-0:–
and the following apply.
___________
Under preparation. Stage at the time of publication: IEC CDV 63522-0:2024.
Under preparation. Stage at the time of publication: IEC FDIS 63522-1:2025.
Under preparation. Stage at the time of publication: IEC FDIS 63522-7:2024.

– 6 – IEC 63522-16:2025 © IEC 2025
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
surface-mounted device
SMD
device where the electrical connection on the surface of a conductive pattern is realized without
utilizing component holes
4 Test procedure
4.1 Purpose
These standard methods are a basic qualification for the resistance of solder processes under
standard conditions or individually as defined by the manufacturer.
The final product fitting the selected solder process shall be investigated by the users under
their responsibility.
Each kind of deviation from the given test conditions or process shall be explicitly described in
the test report. In such case it is not allowed to reference a test as according to this document.
If there is any deviation, the test report shall be named as "similar to".
To determine
• the ability of relay terminals to wet easily with solder,
• and/or the ability of the relay to withstand soldering heat,
solder terminals and their supports shall have a sufficient resistance to any soldering heat.
These tests are only applicable to relays and sockets where the manufacturer has specified the
ability of terminations to a soldering process.
NOTE There are some industrial relays where the terminal could be used in conjunction with flat-quick connector
as well as direct wire soldered.
4.2 Procedure
4.2.1 General
The following soldering heat resistance tests are defined as standard tests for relays.
4.2.2 Resistance to soldering heat
4.2.2.1 Method – Soldering iron method
4.2.2.1.1 Purpose
The object of this test is to evaluate the solderability of relay terminations and ability to
withstand the heating stress produced by soldering iron.
4.2.2.1.2 Procedure
The test is carried out according to test Tb of IEC 60068-2-20 as given in Table 1 for method 2
or the conditions individually specified by the manufacturer.

The conditions of IEC 60068-2-20 are recommended, but if soldering is difficult, the conditions
shall be stated individually by the manufacturer.
A functional test according to IEC 63522-7 shall be performed before as well as after the
soldering.
4.2.2.2 Method – Solder bath
4.2.2.2.1 Purpose
The object of this test is to detail a standard test method to evaluate the solderability of relay
terminations to withstand the heating stresses produced by a mass soldering operation.
4.2.2.2.2 Procedure
4.2.2.2.2.1 General
The test is carried out according to test Tb of IEC 60068-2-20 as given in Table 1.
A functional test according to IEC 63522-7 shall be performed before as well as after the
soldering.
Table 1 – Test conditions for test Tb
Subclauses of IEC 60068-2-20:2021 Conditions
5.1.2 Functional test according to IEC 63522-7 as initial measurement
Method 1 5.2.4 Method 1A: solder bath at (260 ± 3) °C
5.2.4 Duration of immersion: (5 ± 0,5) s
5.3.3 Method 2: soldering iron at 350 °C
5.3.1 Soldering iron of size 'B'
Method 2
5.3.3 No cooling device
5.3.3 Duration of application of the soldering iron: (10 ± 1) s

4.2.2.2.2.2 Solder pins (terminals)
The test is carried out according to test Tb of IEC 60068-2-20 as given in Table 1 for method 1.
Terminals for mounting on printed circuit boards shall be fitted with a thermal screen (simulating
a printed board) of (1,5 ± 0,1) mm thickness. During the test, immersion shall be effectuated
only up to the lower surface of this screen. The screen shall be used instead of a printed circuit
board (PCB).
NOTE To avoid any influence from the screen to the wetting, screens with hole diameters 1 mm larger than the pin
size are commonly used.
4.2.2.2.2.3 Other solder terminations (e.g. soldering lugs)
This test shall be carried out as indicated by the manufacturer in accordance with test method 1
as given in Table 1.
4.2.2.3 Terminals for surface mounting (SMD)
This test shall be carried out according to the procedure of IEC 61760-1:2020, 7.2, as stated
by the manufacturer.
– 8 – IEC 63522-16:2025 © IEC 2025
4.2.3 Resistance to standard industrial soldering processes
4.2.3.1 General
These tests define reference profiles for verification of the resistance against the machine
soldering process. They may be used to show the product ability to withstand the heat influence
during an industrial soldering process.
For the qualification the selected two soldering processes are the standard methods for
investigation.
4.2.3.2 Method – Double wave soldering process
4.2.3.2.1 General
The double wave solder profile shall be according to Figure 1 and is suitable for all relays with
solder terminals as standard profile.
Instead of a standard wave, a single wave with a contact time of a total of 10 s maximum is
permitted. A minimum of 8 s is defined.
4.2.3.2.2 Profile
Figure 1 – Double wave soldering profile
A functional test according to IEC 63522-7 shall be performed before as well as after the
soldering.
4.2.3.2.3 Conditions
This test shall be carried out in accordance with IEC 61760-1 in addition to conditions according
to 4.2.
4.2.3.3 Method – Reflow soldering process
4.2.3.3.1 General
The reflow soldering process is the standard test for SMD and through hole reflow (THR)
suitable relays and feasible only for special reflow relay types and SMD relay types according
to the manufacturer specification.
The reflow soldering profile shall be according to Figure 1.
4.2.3.3.2 Profile
Figure 2 – SMT and through hole soldering profile
A functional test according to IEC 63522-7 shall be performed before as well as after the
soldering.
4.2.3.3.3 Conditions
This test shall be carried out in accordance with IEC 61760-1 in addition to conditions according
to 4.2.
4.2.4 Solderability, wetting – Wetting balanced method
4.2.4.1 Purpose
The object of this test is to define test methods to assess the solderability of the terminations
of a component designed for use with printed boards or for other applications using similar
soldering techniques.
4.2.4.2 Procedure
The test shall be carried out in accordance with test Ta of IEC 60068-2-69.
The DUT shall consist of a single termination of a component. It is not permitted to clean or
degrease the terminations prior to the application of the soldering test, unless otherwise
specified.
NOTE Any touch of the termination can bring contamination.

– 10 – IEC 63522-16:2025 © IEC 2025
Any accelerated ageing should be chosen from IEC 60068-2-20:2021, 4.1.4.1. It is
recommended to use type 4 as the preferred method.
Non-activated flux as specified in IEC 60068-2-20:2021, Annex B, shall be used.
The force-time curve shall be recorded.
4.3 Conditions
The following conditions shall be specified:
• test procedure, severities (duration and temperatures) and other details for those methods;
• ageing/preconditioning procedures, if required;
• all parameters to carry out the related tests, such as:
– bath temperatures, if applicable;
– penetration (contact) time with the solder bath, if applicable;
– immersion depth, if applicable;
– number of DUTs
– ambient conditions, if applicable;
– minimum wetting force, if applicable;
– any other observation;
– number of terminals/samples to be inspected, if applicable;
i) any preparation of the DUT, if applicable;
ii) any additional information and test be carried out, if applicable;
iii) PCB specification, if used and applicable.
5 Evaluation
5.1 General
After the test of the resistance to soldering heat and subsequent cooling to reference
temperature, the relays shall comply with the requirements of IEC 63522-7 (operate and release)
at room temperature. The solder terminals shall not have worked loose nor have been displaced
in a manner impairing their further use, and they shall still comply with the requirements
(distances) for insulation coordination.
• Visual inspection, no visible defect and/or deformation as specified in IEC 63522-1:–,Clause
4.
• Both measurements – functional test before as well as after the soldering test functional
test shall be within the product specification unless otherwise specified by the manufacturer.
• Sealing test for sealed relays (RT III to RT V) as specified in IEC 63522-11:–, 5.1.3.
For a proper sealing test it is recommended to carefully resolder the DUTs. For very small DUTs
like telecommunication relays it can be necessary to test with the PCB. In such cases it is
recommended to use small PCB's or cut them into small pieces (as close as possible to the
relay outside).
• Other final measurements as required.
For the wetting balanced method only, the wetting force-time curve shall be in line with an
acceptable wetting in accordance with IEC 60068-2-69.

5.2 Test report
If this document is executed as a part of a test record of another s
...