SIST EN ISO 18278-3:2018

SLOVENSKI STANDARD
SIST EN ISO 18278-3:2018
01-marec-2018
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Resistance welding - Weldability - Part 3: Evaluation procedures for weldability in spot
weld bonding (ISO 18278-3:2017)
Widerstandsschweißen - Schweißeignung - Teil 3: Verfahren zum Bewerten der Eignung
für das Widerstandspunktschweißkleben (ISO 18278-3:2017)
Soudage par résistance - Soudabilité - Partie 3: Méthodes d'évaluation de l'aptitude au
soudocollage par points (ISO 18278-3:2017)
Ta slovenski standard je istoveten z: EN ISO 18278-3:2017
ICS:
25.160.10 Varilni postopki in varjenje Welding processes
SIST EN ISO 18278-3:2018 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 18278-3:2018

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SIST EN ISO 18278-3:2018


EN ISO 18278-3
EUROPEAN STANDARD

NORME EUROPÉENNE

September 2017
EUROPÄISCHE NORM
ICS 25.160.40
English Version

Resistance welding - Weldability - Part 3: Evaluation
procedures for weldability in spot weld bonding (ISO
18278-3:2017)
Soudage par résistance - Soudabilité - Partie 3: Widerstandsschweißen - Schweißeignung - Teil 3:
Méthodes d'évaluation de l'aptitude au soudocollage Verfahren zum Bewerten der Eignung für das
par points (ISO 18278-3:2017) Widerstandspunktschweißkleben (ISO 18278-3:2017)
This European Standard was approved by CEN on 4 June 2017.

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: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18278-3:2017 E
worldwide for CEN national Members.

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SIST EN ISO 18278-3:2018
EN ISO 18278-3:2017 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 18278-3:2018
EN ISO 18278-3:2017 (E)
European foreword
This document (EN ISO 18278-3:2017) 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 March 2018, and conflicting national standards shall
be withdrawn at the latest by March 2018.
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 18278-3:2017 has been approved by CEN as EN ISO 18278-3:2017 without any
modification.
3

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SIST EN ISO 18278-3:2018

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SIST EN ISO 18278-3:2018
INTERNATIONAL ISO
STANDARD 18278-3
First edition
2017-08
Resistance welding — Weldability —
Part 3:
Evaluation procedures for weldability
in spot weld bonding
Soudage par résistance — Soudabilité —
Partie 3: Méthodes d’évaluation de l’aptitude au soudocollage par
points
Reference number
ISO 18278-3:2017(E)
©
ISO 2017

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SIST EN ISO 18278-3:2018
ISO 18278-3:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

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SIST EN ISO 18278-3:2018
ISO 18278-3:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Weld bonding equipment . 2
4.1 General . 2
4.2 Adhesive dispensing equipment . 2
4.3 Storage chamber . 2
4.4 Electrodes . 2
4.5 Welding current . 2
4.6 Mechanical settings . 2
4.7 Measurement of parameters . 2
4.7.1 Temperature . 2
4.7.2 Amount of adhesive applied . 2
4.7.3 Welding current and electrode force . 3
4.7.4 Electrode cooling water flow rate . 3
4.8 Measurement of results . 3
4.8.1 Weld diameter . 3
4.8.2 Detection of expulsion . 3
5 Assembly preparation . 3
6 Preliminary adjustments . 4
6.1 Electrode alignment . 4
6.2 Electrode conditioning . 4
7 Determination of the welding current range . 5
7.1 Test specimens . 5
7.2 Welding parameters . 5
7.3 Test procedure . 5
7.4 Current range criteria . 5
7.5 Three sheet and multiple stack-ups . 6
8 Estimation of electrode life . 6
8.1 Test specimens . 6
8.2 Welding parameters . 6
8.3 Procedure . 6
8.4 Test criteria, interpretation of results . 7
9 Test report . 7
9.1 General . 7
9.2 Welding current range . 8
9.3 Electrode life . 8
Annex A (informative) Electrode alignment . 9
Annex B (informative) Specimens with current shunt .11
Annex C (informative) Specific conditions for steel sheet customer qualification .13
Annex D (informative) Specimens for destructive testing .16
Annex E (informative) Example of a test report for welding current range .18
Annex F (informative) Example of a test report for electrode life test.19
Bibliography .20
© ISO 2017 – All rights reserved iii

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SIST EN ISO 18278-3:2018
ISO 18278-3:2017(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 on 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 the following
URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 44, Welding and allied processes,
Subcommittee SC 6, Resistance welding and allied mechanical joining.
A list of all parts in the ISO 18278 series can be found on the ISO website.
Requests for official interpretations of any aspect of this document should be directed to the Secretariat
of ISO/TC 44/SC 6 via your national standards body. A complete listing of these bodies can be found at
www .iso .org.
iv © ISO 2017 – All rights reserved

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SIST EN ISO 18278-3:2018
ISO 18278-3:2017(E)

Introduction
This document describes procedures for evaluating the weldability of weld bonding using the resistance
spot welding process by determining the welding current range and electrode life.
These procedures can be used to evaluate the following:
a) the effect of electrode material, shape, dimensions and electrode cooling;
b) the effect of material types and thicknesses and coatings being welded;
c) the effect of welding conditions;
d) the effect of welding equipment;
e) the effect of adhesive on welding.
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SIST EN ISO 18278-3:2018

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SIST EN ISO 18278-3:2018
INTERNATIONAL STANDARD ISO 18278-3:2017(E)
Resistance welding — Weldability —
Part 3:
Evaluation procedures for weldability in spot weld bonding
1 Scope
This document specifies procedures for the determination of the acceptable welding current range and
the electrode life for spot weld bonding using resistance spot welding with adhesive bonding.
This document is applicable for the evaluation of the weldability of prepared assemblies of uncoated
and coated metal sheets with individual thicknesses from 0,4 mm to 6,0 mm.
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 669, Resistance welding — Resistance welding equipment — Mechanical and electrical requirements
ISO 5182, Resistance welding — Materials for electrodes and ancillary equipment
ISO 5821, Resistance welding — Spot welding electrode caps
ISO 14373, Resistance welding — Procedure for spot welding of uncoated and coated low carbon steels
ISO 17677-1, Resistance welding — Vocabulary — Part 1: Spot, projection and seam welding
ISO 18278-1:2015, Resistance welding — Weldability — Part 1: General requirements for the evaluation of
weldability for resistance spot, seam and projection welding of metallic materials
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 669, ISO 14373, ISO 17677-1
and ISO 18278-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
spot weld bonding
resistance spot welding through an adhesive or sealant
3.2
substrate
material upon the surface of which an adhesive is spread for weld bonding
3.3
prepared assembly
set of components (substrates and adhesives) positioned prior to welding
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SIST EN ISO 18278-3:2018
ISO 18278-3:2017(E)

3.4
wearing sheet
sheet which is used to produce electrode wear through continuous spot welding
4 Weld bonding equipment
4.1 General
Methods to characterize resistance welding equipment can be found in ISO 669.
The mass and friction of the movable electrode assembly can be determined in accordance with
ISO 18278-1.
4.2 Adhesive dispensing equipment
The adhesive dispensing equipment shall be defined by agreement between the contracting parties.
4.3 Storage chamber
The storage chamber shall have a temperature regulation system that is sufficient to maintain the
properties of the adhesive or sealant, as required by the manufacturer of the adhesive or sealant.
4.4 Electrodes
The electrode materials shall be as defined in ISO 5182. Their geometry shall be defined according to
ISO 5821.
4.5 Welding current
The type of welding current used (alternating current or direct current) shall be specified before
testing and recorded. Constant current control settings shall be used.
When using AC resistance welding equipment, it shall be set so that welding current is not less than
30 % of R.M.S. value at full conduction angle.
4.6 Mechanical settings
The mechanical settings shall be chosen to limit the impact of the electrode meeting the sheet.
To limit the impact of the electrode an electrode approach speed of 0,15 m/s is recommended and/or
the peak force should be less than 150 % of the nominal electrode force.
The machine squeeze time should be of sufficient duration to overcome electrode bounce effects and
machine inertia so as to allow the electrode force to build up to the required value before the welding
current is initiated.
4.7 Measurement of parameters
4.7.1 Temperature
The ambient temperature shall be measured.
4.7.2 Amount of adhesive applied
Measurement of the amount of adhesive applied shall be carried out as defined by the contracting
parties.
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SIST EN ISO 18278-3:2018
ISO 18278-3:2017(E)

For example, measurements can be performed using a calliper gauge, scale magnifier or by relative
weighing.
4.7.3 Welding current and electrode force
Measurement of welding current and electrode force shall be in accordance with ISO 18278-1:2015, 5.3.
4.7.4 Electrode cooling water flow rate
Since water cooling significantly influences electrode life, the inlet water temperature should be
maintained at 20 °C and shall not exceed 30 °C. A separate water supply should be used for each
electrode, and the water flow rate for each electrode shall be a minimum of 4 l/min. The water cooling
tube should be arranged to ensure that the water directly cools the electrode.
Dimensions of the water cooling holes and pipes shall comply with the relevant requirements of the
appropriate ISO Standard for various electrode types. The distance between the back and working face
of the electrode should not exceed the values given in ISO 5821 which specifies electrode dimensions.
Any deviations shall be recorded.
All machine and water cooling details shall be recorded in the format presented in Clause 9.
4.8 Measurement of results
4.8.1 Weld diameter
After destructive testing, the weld diameter shall be measured according to ISO 17677-1.
4.8.2 Detection of expulsion
Occurrence of expulsion shall be determined by
— the electrode displacement curve,
— the welding voltage signal,
— the welding force signal, or
— visually.
In the latter case, expulsion shall be confirmed by visual examination after destructive testing. For steel
sheets, an expulsion is characterized by a very sharp deviation in the trace of an electrode displacement
or welding voltage signal.
5 Assembly preparation
The weld bonding shall be set up according to the indications given in Figure 1. The amount and pattern
of adhesive applied shall be agreed between the contracting parties.
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SIST EN ISO 18278-3:2018
ISO 18278-3:2017(E)

a)  Just after adhesive application
b)  Prepared assembly under application
   of electrode force, just before
c)  After welding
Key
1 upper sheet 4 lower electrode
2 lower sheet 5 adhesive
3 upper electrode 6 nugget
Figure 1 — Stages during spot weld bonding
To ensure reproducible test conditions, it is necessary to define the adhesive characteristics and
dispensing conditions; see 9.1 a) to f).
6 Preliminary adjustments
6.1 Electrode alignment
Electrode alignment shall be checked. This may be accomplished by the methods suggested in Annex A.
Eccentricity (see ISO 669) should be less than 0,5 mm. This may be checked using the carbon imprint
method where a sheet of paper is sandwiched between two carbon papers inserted between the two
caps after which the electrode force is applied. Examples of carbon imprints obtained on the paper
sheet after application of pressure are shown in Figure A.1.
Angular deflection (see ISO 669) should not exceed 5°. A method using a tube is described in Figure A.2.
6.2 Electrode conditioning
Electrodes shall not be conditioned.
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SIST EN ISO 18278-3:2018
ISO 18278-3:2017(E)

7 Determination of the welding current range
7.1 Test specimens
The geometry of test specimens shall be defined for a given welding current range test. Recommended
geometries are those for single spot specimens defined in relevant International Standards, especially
cross-tension specimens (ISO 14272), tensile-shear specimens (ISO 14273), torsion specimens
(ISO 17653), mechanized peel specimens (ISO 14270) or chisel/peel test specimens (ISO 10447). In the
case of the chisel test, the specimens shall have a minimum size of 40 mm × 40 mm with at least 35 mm
overlap.
The spot weld shall be aligned with the median line of the adhesive bead.
For non-conductive adhesives, shunting may be necessary to initiate current flow through the adhesive.
Tensile-shear and cross-tension specimens welding procedures with shunt are shown in Annex B.
Cross-tension, peel and chisel specimens are recommended to obtain accurate weld diameter
measurements.
7.2 Welding parameters
Appropriate welding parameters shall be specified in the instructions or in the test order form.
Proposed sets of welding parameters for steel assemblies are given in Annex C.
7.3 Test procedure
Starting with a level sufficiently low to be under any welding condition, the welding current is increased
in 200 A steps and never decreased. Three test specimens shall be prepared and welded for each current
setting, two will be used for destructive testing and the third will be kept in reserve, for example, for
metallographic analysis.
When splashing occurs, the test shall be continued until the welding current reaches 10 % above the
current after splashing first occurred.
Destructive testing and measurement of the weld diameter shall be performed according to 4.8.1 and
the information supplied in 7.1.
For the purpose of the welding current range determination, only the weld diameter is needed,
therefore, adhesive curing is not required before destructive testing.
7.4 Current range criteria
The minimum weld diameter shall be specified in the instructions.
NOTE This minimum weld diameter can be equal to 3,5√t, t being the thickness of the thinnest sheet of the
assembly.
The upper end of the welding current range, I , is defined as the maximum current setting for which
max
at least two out of three spot welds show no splash and all current settings below satisfy the same
condition.
The lower end of the welding current range, I , is defined as the minimum current setting for which
min
both spot weld specimens which are destructively tested will have a diameter equal or greater than the
defined minimum, and all current settings above until I satisfy the same condition.
max
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SIST EN ISO 18278-3:2018
ISO 18278-3:2017(E)

7.5 Three sheet and multiple stack-ups
In such cases, each interface shall be considered individually. Therefore, the shape and number of test
specimens shall be adapted to test each interface separately (i.e. in the case of instrumented testing,
two specimens per interface and one in reserve for metallographic analysis).
The minimum weld diameters shall be defined for each interface of the stack-up, and the lower end of
the welding current range is defined when every interface reaches its own minimum weld diameter
condition.
The upper end of the welding current range is defined when every interface matches the no-splashing
condition.
8 Estimation of electrode life
8.1 Test specimens
Two types of specimens are to be welded during this test:
a) wearing sheets (e.g. dimensions 300 mm × 400 mm);
b) test strips for weld testing. The size of these strips can be chosen depending on the means used for
destructive testing; however, the overlap area shall be at least 40 mm × 300 mm. Figure D.1 and
Figure D.2 give examples of a test strip and a device for simultaneously separati
...