Soft soldering fluxes - Test methods - Part 16: Flux efficacy test, wetting balance method (ISO 9455-16:2019)

This document specifies a method for the assessment of the efficacy of a soft soldering flux, known as the wetting balance method. It gives a qualitative assessment of the comparative efficacy of two fluxes (for example, a standard and a test flux), based on their capacity to promote wetting of a metal surface by liquid solder. The method is applicable to all flux types in liquid form classified in ISO 9454-1.

Flussmittel zum Weichlöten - Prüfverfahren - Teil 16: Bestimmung der Wirksamkeit des Flussmittels, Verfahren zur Messung der Benetzungskraft (ISO 9455-16:2019)

Dieses Dokument legt ein Verfahren zum Beurteilen der Wirksamkeit eines Flussmittels zum Weichlöten fest, das als Verfahren zur Messung der Benetzungskraft bezeichnet wird. Es bietet eine qualitative Beurteilung für den Vergleich der Wirksamkeit zweier Flussmittel (z. B. ein Standard-Flussmittel mit einem zu prüfenden Flussmittel) hinsichtlich ihrer Fähigkeiten, die Benetzung einer Metalloberfläche durch ein flüssiges Weichlot zu fördern. Das Verfahren ist für alle flüssigen Flussmitteltypen anwendbar, die in ISO 9454-1 aufgeführt sind.
ANMERKUNG Es ist anzunehmen, dass zukünftige Entwicklungen, welche mit verbesserten Verfahren einen reproduzierbaren Oberflächenbereich zum Prüfen ergeben, es möglich machen, dieses Verfahren zum Beurteilen der Flussmittelwirksamkeit quantitativ einzusetzen. Aus diesem Grund sind verschiedene alternative Verfahren zur Vorbereitung der Probenoberfläche in dem vorliegenden Verfahren enthalten.

Flux de brasage tendre - Méthodes d'essai - Partie 16: Essai d'efficacité du flux, méthode à la balance de mouillage (ISO 9455-16:2019)

Le présent document spécifie une méthode pour l'évaluation de l'efficacité d'un flux de brasage tendre, connue sous le nom de méthode à la balance de mouillage. Elle permet une évaluation qualitative de l'efficacité comparée de deux flux faisant l'objet d'une comparaison (par exemple un flux de référence et un flux d'essai), évaluation fondée sur la capacité de ces flux à faciliter le mouillage de la surface d'un métal par le produit d'apport liquide. Cette méthode est applicable à tous les types de flux sous forme liquide classés dans l'ISO 9454‑1.
NOTE       Il est souhaitable que de futurs développements, bénéficiant du progrès technique pour obtenir une gamme de surfaces d'essais reproductibles, permettront à cette méthode d'évaluation de l'efficacité des flux de fournir des résultats quantitatifs. C'est pourquoi plusieurs autres modes opératoires de préparation de la surface de la pièce d'essai sont inclus dans la présente méthode.

Talila za mehko spajkanje - Preskusne metode - 16. del: Preskus učinkovitosti talila z metodo za merjenje omočljivosti (ISO 9455-16:2019)

Ta dokument določa metodo za oceno učinkovitosti talila za mehko spajkanje, znano kot postopek za merjenje omočljivosti. Na osnovi zmogljivosti spodbujanja omočljivosti kovinske površine s tekočim talilom podaja kvalitativno oceno primerjalne učinkovitosti dveh talil (npr. standardnega in preskusnega talila). Ta metoda se uporablja za vse vrste talil v tekoči obliki iz standarda ISO 9454-1.

General Information

Status
Published
Public Enquiry End Date
03-Aug-2019
Publication Date
04-Feb-2020
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
06-Nov-2019
Due Date
11-Jan-2020
Completion Date
05-Feb-2020

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Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 9455-16:2020
01-marec-2020
Nadomešča:
SIST EN ISO 9455-16:2013
Talila za mehko spajkanje - Preskusne metode - 16. del: Preskus učinkovitosti
talila z metodo za merjenje omočljivosti (ISO 9455-16:2019)
Soft soldering fluxes - Test methods - Part 16: Flux efficacy test, wetting balance method
(ISO 9455-16:2019)
Flussmittel zum Weichlöten - Prüfverfahren - Teil 16: Bestimmung der Wirksamkeit des
Flussmittels, Verfahren zur Messung der Benetzungskraft (ISO 9455-16:2019)
Flux de brasage tendre - Méthodes d'essai - Partie 16: Essai d'efficacité du flux,
méthode à la balance de mouillage (ISO 9455-16:2019)
Ta slovenski standard je istoveten z: EN ISO 9455-16:2019
ICS:
25.160.50 Trdo in mehko lotanje Brazing and soldering
SIST EN ISO 9455-16:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 9455-16:2020

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SIST EN ISO 9455-16:2020


EN ISO 9455-16
EUROPEAN STANDARD

NORME EUROPÉENNE

October 2019
EUROPÄISCHE NORM
ICS 25.160.50 Supersedes EN ISO 9455-16:2013
English Version

Soft soldering fluxes - Test methods - Part 16: Flux efficacy
test, wetting balance method (ISO 9455-16:2019)
Flux de brasage tendre - Méthodes d'essai - Partie 16: Flussmittel zum Weichlöten - Prüfverfahren - Teil 16:
Essai d'efficacité du flux, méthode à la balance de Bestimmung der Wirksamkeit des Flussmittels,
mouillage (ISO 9455-16:2019) Verfahren zur Messung der Benetzungskraft (ISO
9455-16:2019)
This European Standard was approved by CEN on 16 September 2019.

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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, 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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9455-16:2019 E
worldwide for CEN national Members.

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SIST EN ISO 9455-16:2020
EN ISO 9455-16:2019 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 9455-16:2020
EN ISO 9455-16:2019 (E)
European foreword
This document (EN ISO 9455-16:2019) 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 April 2020, and conflicting national standards shall be
withdrawn at the latest by April 2020.
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.
This document supersedes EN ISO 9455-16:2013.
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, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 9455-16:2019 has been approved by CEN as EN ISO 9455-16:2019 without any
modification.

3

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SIST EN ISO 9455-16:2020

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SIST EN ISO 9455-16:2020
INTERNATIONAL ISO
STANDARD 9455-16
Third edition
2019-09
Soft soldering fluxes — Test
methods —
Part 16:
Flux efficacy test, wetting balance
method
Flux de brasage tendre — Méthodes d'essai —
Partie 16: Essai d'efficacité du flux, méthode à la balance de
mouillage
Reference number
ISO 9455-16:2019(E)
©
ISO 2019

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SIST EN ISO 9455-16:2020
ISO 9455-16:2019(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
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 2019 – All rights reserved

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SIST EN ISO 9455-16:2020
ISO 9455-16:2019(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 1
5 Principle . 2
6 Reagents . 2
7 Apparatus . 2
8 Test pieces . 3
9 Procedure. 3
9.1 Preparation of the test pieces. 3
9.1.1 Cleaning . 3
9.1.2 Ageing the surface by sulfidation process . 3
9.1.3 Steam ageing the surface . 3
9.1.4 Damp-heat, steady-state ageing . . 4
9.2 Test method . 4
10 Reference value using standard flux . 4
11 Presentation of results . 5
12 Calculation and expression of results . 6
13 Test report . 7
Annex A (normative) Method for the preparation of standard rosin (colophony) based
liquid fluxes having 25 % (by mass) non-volatile content . 8
Annex B (normative) Method for the production of test pieces with a controlled-
contaminated surface for the wetting balance test (artificial sulfidation method) .10
Bibliography .19
© ISO 2019 – All rights reserved iii

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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 12, Soldering materials.
This third edition cancels and replaces the second edition (ISO 9455-16:2013), of which it constitutes a
minor revision.
The main changes compared to the previous edition are as follows:
— Clause 2 has been updated;
— the coding of the fluxes has been updated in accordance with ISO 9454-1:2016;
— the format of this document has been updated.
A list of all parts in the ISO 9455 series can be found on the ISO website.
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.
iv © ISO 2019 – All rights reserved

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SIST EN ISO 9455-16:2020
INTERNATIONAL STANDARD ISO 9455-16:2019(E)
Soft soldering fluxes — Test methods —
Part 16:
Flux efficacy test, wetting balance method
1 Scope
This document specifies a method for the assessment of the efficacy of a soft soldering flux, known as
the wetting balance method. It gives a qualitative assessment of the comparative efficacy of two fluxes
(for example, a standard and a test flux), based on their capacity to promote wetting of a metal surface
by liquid solder. The method is applicable to all flux types in liquid form classified in ISO 9454-1.
NOTE It is hoped that future developments using improved techniques for obtaining a reproducible range
of test surfaces will enable this method for assessing flux efficacy to be quantitative. For this reason, several
alternative procedures for preparing the surface of the test piece are included in the present method.
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 9454-1, Soft soldering fluxes — Classification and requirements — Part 1: Classification, labelling and
packaging
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
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 60068-2-78:2012, Environmental testing — Part 2‑78: Tests; Test Cab: Damp heat, steady state
3 Terms and definitions
No terms and definitions are listed in this document.
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/
4 Symbols
d depth of immersion, in millimetres, of the test piece below the undisturbed solder level
A cross-sectional area, in square millimetres, of the test piece at the solder line
ρ density, in grams per millilitre, of the solder under test at the test temperature
F wetting force, in millinewtons
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t time at which the test piece first makes contact with the surface of the liquid solder in the bath
0
t time at which the solder starts to wet the test piece (point A, see Figure 1), at which point the
1
trace begins to fall
t time at which the recorded force is equal to the upward force due to buoyancy
2
t time at which the trace crosses the reference line
3
5 Principle
The efficacy of the liquid flux under test is compared with that of a standard liquid flux, using a wetting
balance in conjunction with a specified test piece, appropriate to the class of flux under test.
The fluxes under test shall correspond to one of the classes defined in ISO 9454-1 and fulfil the
requirements of ISO 9454-1.
6 Reagents
Use only reagents of recognized analytical quality and only distilled or deionized water.
6.1 Acid cleaning solution, prepared as follows:
Add cautiously, while stirring, 75 ml of sulfuric acid (ρ = 1,84 g/ml) to 210 ml of water and mix. Cool the
solution to room temperature. Add 15 ml of nitric acid (ρ = 1,42 g/ml) and mix thoroughly.
6.2 Acetone.
6.3 Propan-2-ol, complying with the following requirements:
— propan-2-ol: 99,5 % (by mass) minimum;
— acid content: 0,002 % (by mass) maximum;
— non-volatile content: 0,2 % (by mass) maximum.
Isopropyl alcohol (also propan-2-ol, 2-propanol or the abbreviation IPA) is a common name for this
chemical compound, which has the molecular formula C H O.
3 8
7 Apparatus
Usual laboratory apparatus and, in particular, the following.
7.1 Wetting balance and ancillary instrumentation, in accordance with IEC 60068-2-69.
Calibrate the apparatus in accordance with the manufacturer's instructions.
7.2 Solder bath.
As a minimum, the bath temperature shall be capable of being maintained at a temperature
corresponding to the liquidus temperature of the alloy under test plus 35 °C. The test temperature shall
be reported in the test report.
The dimensions of the solder bath shall be such that no portion of the test piece (see Clause 8) is less than
15 mm from the wall of the bath and the depth of the liquid solder in the bath shall be not less than 30 mm.
2 © ISO 2019 – All rights reserved

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The solder used for the test and the test temperature may be one of the following:
— Sn60Pb40 (see ISO 9453) at 235 °C ± 3 °C;
— Sn96,5Ag3,0Cu0,5 (see ISO 9453) at 255 °C ± 3 °C;
— any other solder and temperature combinations as agreed between the customer and the flux
supplier.
7.3 Acid-free filter paper.
8 Test pieces
The test pieces shall be made of copper.
EXAMPLE Test pieces are cut from a rectangular copper sheet. The dimensions of each test piece are as
follows:
— width: 10,0 mm ± 0,1 mm;
— length: constant between 15 mm and 30 mm, to suit the equipment used;
— thickness: either 0,10 mm ± 0,02 mm or 0,30 mm ± 0,05 mm.
When testing fluxes of type 1 or 2 (as defined in ISO 9454-1), full details of the test pieces shall be given
in the test report.
The sheet or other article used for preparing the test pieces shall be clean and free from contamination.
In order to obtain accurate results, the test pieces shall be cut cleanly without leaving significant burrs.
9 Procedure
9.1 Preparation of the test pieces
9.1.1 Cleaning
The test pieces shall be handled with clean tongs throughout. Select sufficient test pieces (see Clause 8)
to allow 10 per test flux and 10 per standard flux. Degrease them in acetone (6.2) and allow to dry.
Immerse them for 20 s in the acid cleaning solution (6.1) at room temperature. Remove the test pieces
from the acid cleaning solution and wash for about five seconds under running tap water. Rinse with
distilled or deionized water then acetone (6.2) and dry with acid-free filter paper (7.3).
If required, the test pieces may be stored in acetone after rinsing them in deionized water. When
needed, they shall be removed from the acetone and dried with acid-free filter paper (7.3).
Subject all the test pieces to one of the ageing procedures given in 9.1.2 to 9.1.4 as agreed between the
flux supplier and the customer.
9.1.2 Ageing the surface by sulfidation process
Carry out the procedure given in Annex B on all the cleaned test pieces (see 9.1.1).
9.1.3 Steam ageing the surface
Carry out the steam ageing procedure given in IEC 60068-2-20:2008, 4.1.1, ageing procedure 1b, for a
period of 4 h on all the cleaned test pieces (see 9.1.1).
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9.1.4 Damp-heat, steady-state ageing
Subject all the cleaned pieces (see 9.1.1) to the test chamber conditions specified in IEC 60068-2-78:2012,
Clause 4, for a period selected from 1 h, 4 h or 24 h.
9.2 Test method
9.2.1 Carry out the following test procedure on each of the 10 test pieces. Complete all 10 tests within
45 min of the preparation stage (see 9.1).
9.2.2 If the flux under test is of type 1 or type 2 (as defined in ISO 9454-1), maintain the temperature
of the solder bath at 235 °C ± 3 °C or 255 °C ± 3 °C (see 7.2).
When testing fluxes which are not type 1 or type 2 (as defined in ISO 9454-1), the bath temperature
requirements and the standard flux to be used for comparison shall be agreed between the flux supplier
and the customer.
9.2.3 Remove one of the test pieces from the acetone, dry it between two sheets of acid-free filter
paper (7.3) and place it in the wetting balance specimen clip so that the long edges are vertical. Dip the
test piece in the flux solution under test at room temperature, to a depth of no less than 3 mm greater
than the depth selected for immersion of the test piece in the solder (see 9.2.5). Avoid excess flux by
withdrawing the test piece cornerwise from the flux. If excess flux is still visible, touch the corner of the
test piece on clean filter paper.
9.2.4 Attach the specimen clip to the wetting balance, ensuring that the bottom edge of the test piece is
horizontal and approximately 20 mm above the solder bath (7.2). Allow it to remain there for 20 s ± 5 s
so that the solvent in the flux can evaporate before the test commences. Some types of flux can require
a drying time which is shorter or longer than 20 s ± 5 s. In these cases, the drying time shall be agreed
between the flux supplier and the customer. During this drying period, adjust the suspension force signal
and recorder trace to the desired zero position.
Immediately before starting the test, scrape the surface of the solder bath with a blade of suitable
material to remove oxides.
9.2.5 Either by raising the solder bath or by lowering the test piece, dip the test piece into the molten
solder at a speed of 20 mm/s ± 5 mm/s to a depth of either 3 mm ± 0,2 mm or 4 mm ± 0,2 mm.
Hold the test piece in this position for 5 s to 10 s and then withdraw it at a speed of 20 mm/s ± 5 mm/s.
Record the wetting force against time for the period during which the test piece is in contact with
the solder.
9.2.6 Repeat steps 9.2.2 to 9.2.5 for each of the remaining nine test pieces.
10 Reference value using standard flux
Carry out the procedure described in Clause 9 using a further 10 test pieces (see Clause 8) but using a
standard flux instead of the flux under test. If the flux under test is of type 1 or type 2 (as defined in
ISO 9454-1), the standard flux prepared as described in Annex A shall be used. If the flux under test is of
type 111 or 121 (as defined in ISO 9454-1), use the standard flux prepared as described in A.5.1. If the
flux under test is of type 112, 113, 122 or 123 (as defined in ISO 9454-1), use the standard flux prepared
as described in A.5.2.
If the flux under test is not of type 1 or type 2, use a standard flux as agreed by the supplier and
customer (see 9.2.2, second paragraph).
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11 Presentation of results
A typical trace of wetting force against time is given in Figure 1.
In Figure 1, non-wetting (upward) forces are shown as negative and wetting (downward) forces as
positive.
Key
F force
t time
a
Test piece buoyancy line.
b
Wetting reference line.
Figure 1 — Recorded trace for wetting balance method showing significant points
The following are the points of significance in Figure 1.
— Time t is the moment at which the test piece first makes contact with the surface of the liquid
0
solder in the bath. It is indicated by a sharp deviation of the recorder trace from the zero-force line.
— Time t is the moment at which the solder starts to wet the test piece and corresponds to point A at
1
which the trace begins to fall.
— Time t , corresponding to point B, is the moment at which the recorded force is equal to the upward
2
force due to buoyancy. The position of the test piece buoyancy line is calculated from the density of
the solder and the depth of immersion of the test piece as follows.
Force at point B, in millinewtons, is equal to Formula (1):
ρdA × 9,81/1 000 (1)
where
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d is the depth of immersion, in millimetres, of the test piece below the undisturbed solder level;
A is the cross-sectional area, in square millimetres, of the test piece at the solder line;
ρ is the density, in grams per millilitre, of the solder under test at the test temperature.
Time t is the moment at which the trace crosses the reference line. The line is drawn at a distance
3
corresponding to a force, F, which depends on the test piece thickness and the immersion depth, as
given in Table 1.
Table 1 — Values of the wetting force as a function of test piece thickness and depth of
immersion
Thickness Immersion depth Force, F
mm mm mN
0,1 3 5,23
0,3 3 5,01
0,1 4 5,17
0,3 4 4,85
NOTE  The force, F, is equal to 2/3 of the theoretical maximum wetting force on the test piece, assuming a wetting angle of
zero and a liquid/vapour surface tension of 0,4 mN/mm.
Point C corresponds to the maximum value of the wetting force attained during the specified
immersion period.
Point D corresponds to the end of the specified immersion period.
12 Calculation and expression of results
12.1 Carry out the procedures and calculations described in 12.2 and 12.3.
12.2 For each of the 10 recorded traces obtained for the sample flux, draw the test piece buoyancy line
through point B (see Clause 11) and draw the wetting reference line 5,6 mN below the buoyancy line (see
Figure 1). Read off the following times, in seconds:
a) the time between t and t (i.e. the time to the start of wetting);
0 1
b) the time between t and t (i.e. the time to reach a wetting force of 5,6 mN).
0 3
Calculate the mean values for a) and b) obtained from the 10 traces.
Measure the force corresponding to point C (i.e. the maximum wetting force). Calculate the mean value
of the maximum wetting force.
12.3 Repeat the operations and calculations described in 12.2 for the 10 recorder traces obtained from
the standard flux in order to obtain the mean values for a), b) and c) for the standard flux.
Compare the mean results for 12.2 a), b) and c) obtained for the flux under test with those obtained
from the 10 results using the standard flux.
Then, assess the efficacy of the flux under test as better than, as good as, or worse than, the standard
flux, in relation to the speed and strength of wetting.
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13 Test report
The test report shall include the following information:
a) the identification of the sample tested, including copper test specification, identification number
and flux identifiers;
b) the test method used (a reference to this document, i.e. ISO 9455-16);
c) the test piece dimensions and, when fluxes of type 1 or type 2 were tested, full details of the test
pieces (see Clause 7);
d) the ageing treatment (see 9.1.2 to 9.1.4);
e) the test temperature (see 6.2);
f) the depth of immersion of the test piece in the molten solder (see 9.2.5);
g) details of the standard flux used for comparison;
h) the results obtained;
i) the nominal temperature range during the test and the actual temperature range recorded during
the test;
j) any unusual features noted during the procedure;
k) details of any operation not specified in the method, or any optional operation which can have
influenced the results;
l) the date of the test.
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SIST EN ISO 9455-16:2020
ISO 9455-16:2019(E)

Annex A
(normative)

Method for the preparation of standard rosin (colophony) based
liquid fluxes having 25 % (by mass) non-volatile content
A.1 General
This annex gives a method for the preparation of two standard rosin (colophony) based liquid fluxes
having 25 % (by mass) non-volatile content, one non-activated and the other halogen-activated
(i.e. type 1111 and type 1123, as defined in ISO 9454-1, respectively). The specifications for the flux
constituents are based on IEC 60068-2-20:2008, Annex B.
The standard flux may be used as a reference against which the efficacy of the flux under t
...

SLOVENSKI STANDARD
oSIST prEN ISO 9455-16:2019
01-julij-2019
Talila za mehko spajkanje - Preskusne metode - 16. del: Preskus učinkovitosti,
postopek za merjenje omočljivosti (ISO/FDIS 9455-16:2019)
Soft soldering fluxes - Test methods - Part 16: Flux efficacy test, wetting balance method
(ISO/FDIS 9455-16:2019)
Flussmittel zum Weichlöten - Prüfverfahren - Teil 16: Bestimmung der Wirksamkeit des
Flussmittels, Verfahren zur Messung der Benetzungskraft (ISO/FDIS 9455-16:2019)
Flux de brasage tendre - Méthodes d'essai - Partie 16: Essai d'efficacité du flux,
méthode à la balance de mouillage (ISO/FDIS 9455-16:2019)
Ta slovenski standard je istoveten z: prEN ISO 9455-16
ICS:
25.160.50 Trdo in mehko lotanje Brazing and soldering
oSIST prEN ISO 9455-16:2019 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 9455-16:2019

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oSIST prEN ISO 9455-16:2019
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 9455-16
ISO/TC 44/SC 12
Soft soldering fluxes — Test
Secretariat: DIN
methods —
Voting begins on:
2019-05-23
Part 16:
Voting terminates on:
Flux efficacy test, wetting balance
2019-08-15
method
Flux de brasage tendre — Méthodes d'essai —
Partie 16: Essai d'efficacité du flux, méthode à la balance de
mouillage
ISO/CEN PARALLEL PROCESSING
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 9455-16:2019(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2019

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oSIST prEN ISO 9455-16:2019
ISO/FDIS 9455-16:2019(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
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 2019 – All rights reserved

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Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 1
5 Principle . 2
6 Reagents . 2
7 Apparatus . 2
8 Test pieces . 3
9 Procedure. 3
9.1 Preparation of the test pieces. 3
9.1.1 Cleaning . 3
9.1.2 Ageing the surface by sulfidation process . 3
9.1.3 Steam ageing the surface . 3
9.1.4 Damp-heat, steady-state ageing . . 4
9.2 Test method . 4
10 Reference value using standard flux . 4
11 Presentation of results . 5
12 Calculation and expression of results . 6
13 Test report . 7
Annex A (normative) Method for the preparation of standard rosin (colophony) based
liquid fluxes having 25 % (by mass) non-volatile content . 8
Annex B (normative) Method for the production of test pieces with a controlled-
contaminated surface for the wetting balance test (artificial sulfidation method) .10
Bibliography .19
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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.o rg/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 12, Soldering materials.
This third edition cancels and replaces the second edition (ISO 9455-16:2013), of which it
constitutes a minor revision.
The main changes compared to the previous edition are as follows:
— Clause 2 has been updated;
— the format of this document has been updated.
A list of all parts in the ISO 9455 series can be found on the ISO website.
iv © ISO 2019 – All rights reserved

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oSIST prEN ISO 9455-16:2019
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 9455-16:2019(E)
Soft soldering fluxes — Test methods —
Part 16:
Flux efficacy test, wetting balance method
1 Scope
This document specifies a method for the assessment of the efficacy of a soft soldering flux, known as
the wetting balance method. It gives a qualitative assessment of the comparative efficacy of two fluxes
(for example, a standard and a test flux), based on their capacity to promote wetting of a metal surface
by liquid solder. The method is applicable to all flux types in liquid form classified in ISO 9454-1.
NOTE It is hoped that future developments using improved techniques for obtaining a reproducible range
of test surfaces will enable this method for assessing flux efficacy to be quantitative. For this reason, several
alternative procedures for preparing the surface of the test piece are included in the present method.
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 9454-1, Soft soldering fluxes — Classification and requirements — Part 1: Classification, labelling and
packaging
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
IEC 60068-2-69, Environmental testing — Part 2‑69: Tests — Test Ta: Solderability testing of electronic
components by the wetting balance (force measurement) method
IEC 60068-2-78:2012, Environmental testing — Part 2‑78: Tests; Test Cab: Damp heat, steady state
3 Terms and definitions
No terms and definitions are listed in this document.
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/
4 Symbols
d depth of immersion, in millimetres, of the test piece below the undisturbed solder level
A cross-sectional area, in square millimetres, of the test piece at the solder line
ρ density, in grams per millilitre, of the solder under test at the test temperature
F wetting force, in millinewtons
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t time at which the test piece first makes contact with the surface of the liquid solder in the bath
0
t time at which the solder starts to wet the test piece (point A, see Figure 1), at which point the
1
trace begins to fall
t time at which the recorded force is equal to the upward force due to buoyancy
2
t time at which the trace crosses the reference line
3
5 Principle
The efficacy of the liquid flux under test is compared with that of a standard liquid flux, using a wetting
balance in conjunction with a specified test piece, appropriate to the class of flux under test.
The fluxes under test shall correspond to one of the classes defined in ISO 9454-1 and fulfil the
requirements of ISO 9454-1.
6 Reagents
Use only reagents of recognized analytical quality and only distilled or deionized water.
6.1 Acid cleaning solution, prepared as follows:
Add cautiously, while stirring, 75 ml of sulfuric acid (ρ = 1,84 g/ml) to 210 ml of water and mix. Cool the
solution to room temperature. Add 15 ml of nitric acid (ρ = 1,42 g/ml) and mix thoroughly.
6.2 Acetone.
6.3 Propan-2-ol, complying with the following requirements:
— propan-2-ol: 99,5 % (by mass) minimum;
— acid content: 0,002 % (by mass) maximum;
— non-volatile content: 0,2 % (by mass) maximum.
Isopropyl alcohol (also propan-2-ol, 2-propanol or the abbreviation IPA) is a common name for this
chemical compound, which has the molecular formula C H O.
3 8
7 Apparatus
Usual laboratory apparatus and, in particular, the following.
7.1 Wetting balance and ancillary instrumentation, in accordance with IEC 60068-2-69.
Calibrate the apparatus in accordance with the manufacturer's instructions.
7.2 Solder bath.
As a minimum, the bath temperature shall be capable of being maintained at a temperature
corresponding to the liquidus temperature of the alloy under test plus 35 °C. The test temperature shall
be reported in the test report.
The dimensions of the solder bath shall be such that no portion of the test piece (see Clause 8) is less than
15 mm from the wall of the bath and the depth of the liquid solder in the bath shall be not less than 30 mm.
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The solder used for the test and the test temperature may be one of the following:
— Sn60Pb40 (see ISO 9453) at 235 °C ± 3 °C;
— Sn96,5Ag3,0Cu0,5 (see ISO 9453) at 255 °C ± 3 °C;
— any other solder and temperature combinations as agreed between the customer and the flux
supplier.
7.3 Acid-free filter paper.
8 Test pieces
The test pieces shall be made of copper.
EXAMPLE Test pieces are cut from a rectangular copper sheet. The dimensions of each test piece are as
follows:
— width: 10,0 mm ± 0,1 mm;
— length: constant between 15 mm and 30 mm, to suit the equipment used;
— thickness: either 0,10 mm ± 0,02 mm or 0,30 mm ± 0,05 mm.
When testing fluxes of type 1 or 2 (as defined in ISO 9454-1), full details of the test pieces shall be given
in the test report.
The sheet or other article used for preparing the test pieces shall be clean and free from contamination.
In order to obtain accurate results, the test pieces shall be cut cleanly without leaving significant burrs.
9 Procedure
9.1 Preparation of the test pieces
9.1.1 Cleaning
The test pieces shall be handled with clean tongs throughout. Select sufficient test pieces (see Clause 8)
to allow 10 per test flux and 10 per standard flux. Degrease them in acetone (6.2) and allow to dry.
Immerse them for 20 s in the acid cleaning solution (6.1) at room temperature. Remove the test pieces
from the acid cleaning solution and wash for about five seconds under running tap water. Rinse with
distilled or deionized water then acetone (6.2) and dry with acid-free filter paper (7.3).
If required, the test pieces may be stored in acetone after rinsing them in deionized water. When
needed, they shall be removed from the acetone and dried with acid-free filter paper (7.3).
Subject all the test pieces to one of the ageing procedures given in 9.1.2 to 9.1.4 as agreed between the
flux supplier and the customer.
9.1.2 Ageing the surface by sulfidation process
Carry out the procedure given in Annex B on all the cleaned test pieces (see 9.1.1).
9.1.3 Steam ageing the surface
Carry out the steam ageing procedure given in IEC 60068-2-20:2008, 4.1.1, ageing procedure 1b, for a
period of 4 h on all the cleaned test pieces (see 9.1.1).
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9.1.4 Damp-heat, steady-state ageing
Subject all the cleaned pieces (see 9.1.1) to the test chamber conditions specified in IEC 60068-2-
78:2012, Clause 4, for a period selected from 1 h, 4 h or 24 h.
9.2 Test method
9.2.1 Carry out the following test procedure on each of the 10 test pieces. Complete all 10 tests within
45 min of the preparation stage (see 9.1).
9.2.2 If the flux under test is of type 1 or type 2 (as defined in ISO 9454-1), maintain the temperature
of the solder bath at 235 °C ± 3 °C or 255 °C ± 3 °C (see 7.2).
When testing fluxes which are not type 1 or type 2 (as defined in ISO 9454-1), the bath temperature
requirements and the standard flux to be used for comparison shall be agreed between the flux supplier
and the customer.
9.2.3 Remove one of the test pieces from the acetone, dry it between two sheets of acid-free filter
paper (7.3) and place it in the wetting balance specimen clip so that the long edges are vertical. Dip the
test piece in the flux solution under test at room temperature, to a depth of no less than 3 mm greater
than the depth selected for immersion of the test piece in the solder (see 9.2.5). Avoid excess flux by
withdrawing the test piece cornerwise from the flux. If excess flux is still visible, touch the corner of the
test piece on clean filter paper.
9.2.4 Attach the specimen clip to the wetting balance, ensuring that the bottom edge of the test piece is
horizontal and approximately 20 mm above the solder bath (7.2). Allow it to remain there for 20 s ± 5 s
so that the solvent in the flux can evaporate before the test commences. Some types of flux can require
a drying time which is shorter or longer than 20 s ± 5 s. In these cases, the drying time shall be agreed
between the flux supplier and the customer. During this drying period, adjust the suspension force signal
and recorder trace to the desired zero position.
Immediately before starting the test, scrape the surface of the solder bath with a blade of suitable
material to remove oxides.
9.2.5 Either by raising the solder bath or by lowering the test piece, dip the test piece into the molten
solder at a speed of 20 mm/s ± 5 mm/s to a depth of either 3 mm ± 0,2 mm or 4 mm ± 0,2 mm.
Hold the test piece in this position for 5 s to 10 s and then withdraw it at a speed of 20 mm/s ± 5 mm/s.
Record the wetting force against time for the period during which the test piece is in contact with
the solder.
9.2.6 Repeat steps 9.2.2 to 9.2.5 for each of the remaining nine test pieces.
10 Reference value using standard flux
Carry out the procedure described in Clause 9 using a further 10 test pieces (see Clause 8) but using a
standard flux instead of the flux under test. If the flux under test is of type 1 or type 2 (as defined in
ISO 9454-1), the standard flux prepared as described in Annex A shall be used. If the flux under test is
of type 1.1.1 or 1.2.1 (as defined in ISO 9454-1), use the standard flux prepared as described in A.5.1. If
the flux under test is of type 1.1.2, 1.1.3, 1.2.2 or 1.2.3 (as defined in ISO 9454-1), use the standard flux
prepared as described in A.5.2.
If the flux under test is not of type 1 or type 2, use a standard flux as agreed by the supplier and
customer (see 9.2.2, second paragraph).
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11 Presentation of results
A typical trace of wetting force against time is given in Figure 1.
In Figure 1, non-wetting (upward) forces are shown as negative and wetting (downward) forces as
positive.
Key
F force
t time
a
Test piece buoyancy line.
b
Wetting reference line.
Figure 1 — Recorded trace for wetting balance method showing significant points
The following are the points of significance in Figure 1.
— Time t is the moment at which the test piece first makes contact with the surface of the liquid
0
solder in the bath. It is indicated by a sharp deviation of the recorder trace from the zero-force line.
— Time t is the moment at which the solder starts to wet the test piece and corresponds to point A at
1
which the trace begins to fall.
— Time t , corresponding to point B, is the moment at which the recorded force is equal to the upward
2
force due to buoyancy. The
...

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