SIST EN ISO 14373:2024

SLOVENSKI STANDARD
01-junij-2024
Nadomešča:
SIST EN ISO 14373:2015
Uporovno varjenje - Postopek točkovnega varjenja neprevlečenih in prevlečenih
maloogljičnih jekel (ISO 14373:2024)
Resistance welding - Procedure for spot welding of uncoated and coated low carbon
steels (ISO 14373:2024)
Widerstandsschweißen - Verfahren zum Punktschweißen von niedriglegierten Stählen
mit oder ohne metallischem Überzug (ISO 14373:2024)
Soudage par résistance - Mode opératoire pour le soudage par points des aciers à bas
carbone revêtus et non revêtus (ISO 14373:2024)
Ta slovenski standard je istoveten z: EN ISO 14373:2024
ICS:
25.160.10 Varilni postopki in varjenje Welding processes
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 14373
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2024
EUROPÄISCHE NORM
ICS 25.160.10 Supersedes EN ISO 14373:2015
English Version
Resistance welding - Procedure for spot welding of
uncoated and coated low carbon steels (ISO 14373:2024)
Soudage par résistance - Mode opératoire pour le Widerstandsschweißen - Verfahren zum
soudage par points des aciers à bas carbone revêtus et Punktschweißen von niedriglegierten Stählen mit oder
non revêtus (ISO 14373:2024) ohne metallischem Überzug (ISO 14373:2024)
This European Standard was approved by CEN on 29 December 2023.

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, Türkiye 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
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14373:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 14373:2024) 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 July 2024, and conflicting national standards shall be
withdrawn at the latest by July 2024.
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 14373:2015.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
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, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 14373:2024 has been approved by CEN as EN ISO 14373:2024 without any modification.

International
Standard
ISO 14373
Third edition
Resistance welding — Procedure
2024-01
for spot welding of uncoated and
coated low-carbon steels
Soudage par résistance — Mode opératoire pour le soudage par
points des aciers à bas carbone revêtus et non revêtus
Reference number
ISO 14373:2024(en) © ISO 2024
ISO 14373:2024(en)
© ISO 2024
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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 14373:2024(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 2
5 Materials . 2
5.1 Form .2
5.2 Coatings .2
6 Surface conditions . 2
7 Edge conditions, form of component and weld pitch . 2
8 Electrodes . . 3
8.1 Materials .3
8.2 Dimensions .3
8.3 Cooling of electrodes .4
9 Weld assessment . 4
9.1 General .4
9.2 Weldability testing .5
9.3 Production testing .5
9.4 Frequency of testing .5
10 Weld quality requirements . 5
10.1 Weld diameter .5
10.2 Failure description of welds .6
10.3 Weld strength .6
10.4 Visual examination .7
10.4.1 Surface condition .7
10.4.2 Distortion .7
11 Multi-weld arrays . 8
Annex A (informative) Recommendations for spot-welding equipment . 9
Annex B (informative) Typical spot-welding conditions . 10
Annex C (informative) Partial list of steel types applicable to this document .12
Bibliography . 14

iii
ISO 14373:2024(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 6, Resistance welding and allied mechanical joining, in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/TC 121, Welding and allied processes, in accordance with
the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 14373:2015), which has been technically
revised.
The main changes are as follows:
— figures showing failure types and modes for tensile shear and cross tension testing removed;
— new coating types added;
— cross-tension strength (CTS) values added;
— tensile shear strength (TSS) formula removed;
— tolerance for distortions reduced.
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. Official interpretations of ISO/TC 44 documents, where they exist, are
available from this page: https://committee.iso.org/sites/tc44/home/interpretation.html.

iv
ISO 14373:2024(en)
Introduction
Information on appropriate welding equipment is given in Annex A and information on spot-welding
conditions is given in Annex B. This information is provided for guidance only.
Depending on the service conditions of the fabrication, the type of welding equipment, the characteristics
of the secondary circuit, the electrode force actuation system, the electrode material and the shape, it is
possible that certain modifications will be necessary. In such cases, further information can be obtained
from the relevant application standard, where one exists.

v
International Standard ISO 14373:2024(en)
Resistance welding — Procedure for spot welding of uncoated
and coated low-carbon steels
1 Scope
This document specifies requirements for resistance spot welding in the fabrication of assemblies of
uncoated and metallic-coated or weldable non-metallic-coated low-carbon steel, comprising two or three
sheets of metal, where the maximum single-sheet thickness of components to be welded is within the range
0,4 mm to 3,0 mm.
This document is applicable to welding of sheets of the same or unequal thickness, where the thickness ratio
is less than or equal to 3:1.
Welding with the following types of equipment is within the scope of this document:
a) pedestal welding equipment;
b) portable welding guns;
c) automatic welding equipment where the components are fed by robots or automatic feeding equipment;
d) multi-spot-welding machines;
e) robotic welding machines.
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 10447, Resistance welding — Testing of welds — Peel and chisel testing of resistance spot and projection
welds
ISO 15609-5, Specification and qualification of welding procedures for metallic materials — Welding procedure
specification — Part 5: Resistance welding
ISO 15614-12, Specification and qualification of welding procedures for metallic materials — Welding procedure
test — Part 12: Spot, seam and projection welding
ISO 17677-1, Resistance welding — Vocabulary — Part 1: Spot, projection and seam welding
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 17677-1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
weld pitch
centre-to-centre distance between adjacent spot welds

ISO 14373:2024(en)
3.2
edge distance
distance from the edge of the component to the centre of a weld
4 Symbols
Symbol Term Unit
d weld diameter (see ISO 17677-1) mm
w
d electrode tip diameter mm
e
t sheet thickness mm
5 Materials
5.1 Form
The steel shall be flat rolled, in coil or cut to length, and shall be free from harmful imperfections.
5.2 Coatings
A partial list of coatings to which this document is applicable is given in Annex C.
6 Surface conditions
Prior to welding, all surfaces of components to be welded shall be free from grease, scale, rust, paint, dirt or
excessive pitting. Standard oiling from rolling or stamping operations is not detrimental to welding.
When the steel sheet has been hot formed, it shall be sandblasted (or processed by any equivalent cleaning
process) prior to welding to remove the oxides formed during the hot forming operation. Steel sheets coated
with aluminium-silicon coatings can be welded directly after hot forming without sandblasting.
Uncoated hot-rolled steel shall be in the pickled condition.
Coated steels can be supplied with a chromate or phosphate passivation treatment. Phosphated uncoated
steel may also be used. These materials can be welded, although adjustment can be required to the welding
parameters outlined in Annex B. Generally speaking, only thin phosphate pre-treatment of steel is acceptable
prior to spot welding.
Certain surface treatments, such as the application of paint primers, weldable organic coatings, rust
preventatives and oils, can be applied before welding, provided that the coating is uniform in thickness
and it has been shown that consistent welds conforming to this document can be obtained. Excessive use of
surface pre-treatment reduces the length of electrode life.
7 Edge conditions, form of component and weld pitch
The components to be welded shall be free from any burrs or other defects which could interfere with
interface contact in some way or which could necessitate excessive force in fitting the parts together.
The shape of the component should be such that there is satisfactory interfacial contact in the area where
the welds are to be made. The edge distance should not be less than 1,25 d (see Figure 1), where d is the
w w
weld diameter as defined in 10.1. The use of edge distances less than the recommended values influences
weld quality adversely. In such cases, the nominal weld size specified may be less than that given in 10.1,
therefore due allowance is needed for a lower weld strength (see 10.4).
The weld pitch (see Figure 1) should be greater than 16 t and 3 d . Tolerances for the weld pitch should not
w
exceed ± 10 %, provided that it does not fall below the minimum value. If the weld pitch is too short, the

ISO 14373:2024(en)
shunting current through the previous weld will reduce the size of the following weld. An increase of the
welding current can partially mitigate the problem.
8 Electrodes
8.1 Materials
The electrode materials shall be a copper alloy and should possess high thermal and electrical conductivity.
They should conform to and be used in accordance with ISO 5182.
8.2 Dimensions
The welding electrodes should be of sufficient cross-sectional area and strength to carry the welding current
and electrode force without overheating, excessive deformation or excessive deflection.
The electrode dimensions should conform to ISO 1089 for taper fits, ISO 5184 for straight electrodes,
ISO 5830 for male electrode caps and ISO 5821 for female electrode caps, as applicable.
Key
d weld diameter
w
t sheet thickness
r corner radius
Corner radius r should be between one and three times the sheet thickness t.
Figure 1 — Recommended edge conditions and weld pitch
When welding two sheets of thickness up to and including 3 mm using truncated cone type electrodes, the
electrode tip diameter should be chosen from standard sizes according to Formula (1).
d = a√t (1)
e
ISO 14373:2024(en)
where
d is the initial tip diameter, in mm;
e
t is the thickness of the sheet in contact with the electrode, in mm;
a is a factor usually between 5 and 7.
When using domed electrodes (e.g. Type F0 according to ISO 5821) with small tip radii or electrodes with
very small working faces, Formula (1) does not always apply, in which case the electrode dimensions depend
on accessibility and flange width. In such cases, the electrode tip dimensions and welding conditions are
selected to give a weld diameter as specified in 10.1.
When welding two sheets of unequal thickness, the electrode dimensions should be specified with reference
to the thinner sheet thickness. In the case of three thicknesses, the thinner sheet of each combination should
be used as the reference.
Where a pad or mandrel is used as the second electrode, its surface shall be maintained to match the
...