SIST EN ISO 18275:2026

• Abstract:

  This document specifies requirements for classification of covered electrodes and deposited metal in the as-welded condition and in the post-weld heat-treated condition for manual metal arc welding of high-strength steels with a minimum yield strength greater than 500 MPa or a minimum tensile strength greater than 570 MPa.; This document is a combined specification providing a classification utilizing a system based on the yield strength and an average impact energy of 47 J of the all-weld metal, or utilizing a system based on the tensile strength and an average impact energy of 27 J of the all-weld metal.; Clauses, subclauses and tables which carry the suffix “System A” are applicable only to covered electrodes classified under the system based on the yield strength and an average impact energy of 47 J of the all-weld metal given in this document.; Clauses, subclauses and tables which carry the suffix “System B” are applicable only to covered electrodes classified under the system based on the tensile strength and an average impact energy of 27 J of the all-weld metal given in this document.; Subclauses and tables which do not have either the suffix “System A” or the suffix “System B” are applicable to all covered electrodes classified under this document.

• Status: Published
• Public Enquiry End Date: 01-Dec-2025
• Publication Date: 19-Aug-2026
• ICS: 25.160.20 - Welding consumables
• Technical Committee: VAR - Welding
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 22-Jul-2026
• Due Date: 26-Sep-2026
• Completion Date: 20-Aug-2026
• Ref Project: EN ISO 18275:2026 - Welding consumables - Covered electrodes for manual metal arc welding of high-strength steels - Classification (ISO 18275:2026)

• Replaces: SIST EN ISO 18275:2018 - Welding consumables - Covered electrodes for manual metal arc welding of high-strength steels - Classification (ISO 18275:2018)
• Effective Date: 01-Sep-2026
• Referred By: SIST EN 1090-2:2018+A1:2024 - Execution of steel structures and aluminium structures - Part 2: Technical requirements for steel structures
• Effective Date: 27-May-2026
• Referred By: SIST EN 12732:2013+A1:2014 - Gas infrastructure - Welding steel pipework - Functional requirements
• Effective Date: 27-May-2026
• Referred By: SIST EN 14532-1:2005 - Welding consumables - Test methods and quality requirements - Part 1: Primary methods and conformity assessment of consumables for steel, nickel and nickel alloys
• Effective Date: 27-May-2026
• Referred By: SIST EN 12732:2013 - Gas infrastructure - Welding steel pipework - Functional requirements
• Effective Date: 27-May-2026
• Referred By: SIST EN 1090-2:2008+A1:2012 - Execution of steel structures and aluminium structures - Part 2: Technical requirements for steel structures
• Effective Date: 27-May-2026
• Referred By: SIST EN 12732:2022 - Gas infrastructure - Welding steel pipework - Functional requirements
• Effective Date: 27-May-2026
• Referred By: SIST EN 1090-2:2018 - Execution of steel structures and aluminium structures - Part 2: Technical requirements for steel structures
• Effective Date: 27-May-2026

Overview

SIST EN ISO 18275:2026 defines the requirements for the classification of covered electrodes and deposited metal used in manual metal arc welding of high-strength steels. Developed by the Slovenian Institute for Standardization (SIST) based on ISO 18275:2026, this standard addresses the needs of industries requiring welding consumables for steels with minimum yield strength over 500 MPa or minimum tensile strength over 570 MPa. The document outlines two main classification systems based on either yield or tensile strength and specifies the required impact energy performance of the all-weld metal.

The standard offers a harmonized approach, enabling manufacturers, purchasers, and end-users to classify and specify covered electrodes for high-strength steel applications, ensuring weld quality, mechanical performance, and safety.

Key Topics

• Dual Classification Systems:
  • System A: Based on minimum yield strength and a 47 J average impact energy of the all-weld metal.
  • System B: Based on minimum tensile strength and a 27 J average impact energy of the all-weld metal.
• Compulsory and Optional Classification Elements:
  • Clear identification of which elements (product/process type, mechanical properties, chemical composition, electrode covering, post-weld heat treatment, electrode efficiency, welding position, and hydrogen content) are mandatory or optional for classification under both systems.
• Designation Structure:
  • Provides a systematic structure for product labeling, enabling quick specification and identification by suppliers and buyers.
• Mechanical and Chemical Requirements:
  • Defines performance metrics such as yield strength, tensile strength, elongation, and impact energy.
  • Outlines chemical composition ranges for all-weld metal, ensuring compatibility and desired welding results.
• Test Procedures:
  • Describes standardized test methods for mechanical properties, chemical analysis, and hydrogen content-essential for product evaluation and quality control.

Applications

• Construction and Structural Engineering:
  Used in the fabrication and repair of bridges, buildings, and infrastructure requiring high-strength steel components while maintaining safety-critical weld performance.
• Heavy Machinery Manufacturing:
  Essential for sectors like mining, shipbuilding, and transport, where high-strength joints are required to withstand demanding operational conditions.
• Pipeline and Pressure Vessel Fabrication:
  Suitable for the oil, gas, and petrochemical industries where high-strength steels are prevalent and weld reliability is crucial.
• Standards-Driven Procurement:
  Enables purchasing professionals and engineers to specify electrodes with confidence, ensuring product consistency and compliance in global supply chains.
• QA/QC and Certification:
  Facilitates quality assurance and control processes by providing a recognized reference for product conformity, supporting audits and third-party certification.

Related Standards

• ISO 544: Welding consumables – Technical delivery conditions for filler materials and fluxes
• ISO 2560: Welding consumables – Covered electrodes for manual metal arc welding of non-alloy and fine grain steels
• ISO 2401: Welding consumables – Covered electrodes – Determination of efficiency, metal recovery, and deposition coefficient
• ISO 3690: Welding and allied processes – Determination of hydrogen content in arc weld metal
• ISO 6847: Welding consumables – Deposition of a weld metal pad for chemical analysis
• ISO 6947: Welding and allied processes – Welding positions
• ISO 14344: Welding consumables – Procurement of filler materials and fluxes

Practical Value

SIST EN ISO 18275:2026 ensures that covered electrodes for manual metal arc welding of high-strength steels are classified using industry-accepted, repeatable criteria regarding mechanical and chemical properties. This helps eliminate ambiguity in product selection, supports regulatory compliance, promotes interoperability across industries, and upholds the integrity and safety of welded structures operating under high loads or challenging environments.

Keywords: covered electrodes, welding consumables, manual metal arc welding, high-strength steels, electrode classification, impact energy, tensile strength, yield strength, SIST, ISO 18275, welding standards, electrode specification, welding quality.

SLOVENSKI STANDARD
01-september-2026
Nadomešča:
SIST EN ISO 18275:2018
Dodajni in pomožni materiali za varjenje - Oplaščene elektrode za ročno obločno
varjenje visokotrdnostnih jekel - Razvrstitev (ISO 18275:2026)
Welding consumables - Covered electrodes for manual metal arc welding of high-
strength steels - Classification (ISO 18275:2026)
Schweißzusätze - Umhüllte Stabelektroden zum Lichtbogenhandschweißen von
hochfesten Stählen (ISO 18275:2026)
Produits consommables de soudage - Électrodes enrobées pour le soudage manuel à
l'arc des aciers à haute résistance - Classification (ISO 18275:2026)
Ta slovenski standard je istoveten z: EN ISO 18275:2026
ICS:
25.160.20 Potrošni material pri varjenju Welding consumables
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 18275
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2026
EUROPÄISCHE NORM
ICS 25.160.20 Supersedes EN ISO 18275:2018
English Version
Welding consumables - Covered electrodes for manual
metal arc welding of high-strength steels - Classification
(ISO 18275:2026)
Produits consommables de soudage - Électrodes Schweißzusätze - Umhüllte Stabelektroden zum
enrobées pour le soudage manuel à l'arc des aciers à Lichtbogenhandschweißen von hochfesten Stählen
haute résistance - Classification (ISO 18275:2026) (ISO 18275:2026)
This European Standard was approved by CEN on 16 January 2026.

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
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 18275:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 18275:2026) 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 AFNOR.
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 November 2026, and conflicting national standards
shall be withdrawn at the latest by November 2026.
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 18275:2018.
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 18275:2026 has been approved by CEN as EN ISO 18275:2026 without any modification.

International
Standard
ISO 18275
Fourth edition
Welding consumables — Covered
2026-05
electrodes for manual metal arc
welding of high-strength steels —
Classification
Produits consommables de soudage — Électrodes enrobées
pour le soudage manuel à l'arc des aciers à haute résistance —
Classification
Reference number
ISO 18275:2026(en) © ISO 2026
ISO 18275:2026(en)
© ISO 2026
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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 18275:2026(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Classification . 2
4.1 General .2
4.2 Classification systems .2
4.3 Compulsory and optional sections .3
4.3.1 General .3
5 Symbols and requirements . 3
5.1 Symbol for the product/process .3
5.2 Symbol for tensile properties of all-weld metal .4
5.2.1 System A . .4
5.2.2 System B .4
5.3 Symbol for impact properties of all-weld metal .4
5.3.1 System A . .4
5.3.2 System B .4
5.4 Symbol for chemical composition of all-weld metal.5
5.4.1 System A . .5
5.4.2 System B .6
5.5 Symbol for type of electrode covering .7
5.5.1 System A . .7
5.5.2 System B .7
5.6 Symbol for condition of post-weld heat treatment of all-weld metal .8
5.6.1 System A . .8
5.6.2 System B .8
5.7 Symbol for electrode efficiency and type of current .8
5.7.1 System A . .8
5.7.2 System B .9
5.8 Symbol for welding position .9
5.8.1 System A . .9
5.8.2 System B .9
5.9 Symbol for diffusible hydrogen content of deposited metal .9
5.10 Mechanical property and composition requirements .10
5.10.1 System A . .10
5.10.2 System B .10
6 Mechanical property tests .15
6.1 General . 15
6.2 Preheating and interpass temperatures . 15
6.2.1 System A . . 15
6.2.2 System B . 15
6.3 Pass sequence . 15
6.3.1 General . 15
6.3.2 System A . .16
6.3.3 System B .16
7 Chemical analysis . .16
7.1 General .16
7.1.1 System A . .16
7.1.2 System B .16
8 Rounding procedure .16

iii
ISO 18275:2026(en)
9 Retests .16
10 Technical delivery conditions . 16
11 Examples of designation . 17
11.1 General .17
11.2 Example 1 – System A . .17
11.3 Example 2 – System B .17
11.4 Example 3 – System A . .18
11.5 Example 4 – System B .19
Annex A (informative) Classification systems .20
Annex B (informative) Description of types of electrode covering — System A .22
Annex C (informative) Description of types of electrode covering — System B .23
Annex D (informative) Notes on diffusible hydrogen .25
Annex E (informative) Description of chemical composition symbols — System A .26
Annex F (informative) Description of chemical composition symbols — System B .27
Bibliography .28

iv
ISO 18275:2026(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 3, Welding consumables, 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 fourth edition cancels and replaces the third edition (ISO 18275:2018), which has been technically
revised.
The main changes are as follows:
— this document has been reformatted in single column showing System A and System B in tables and
separate clauses and subclauses, some which are new;
— this document shows system A and system B in a simplified manner with an explanation of each system
in Clause 4 and the scope;
— normative references have been updated;
— all tables have been updated and reorganized;
— N6M4 has been added to Table 6;
— E7618-N6M4 A has been added to Table 11 and Table 12;
— the type of current has been updated in Table 7 has been updated to reflect ISO 2560;
— in 5.6.2, the tolerance for holding time has been relaxed except for E6218-N4M2 P
— in 6.1, clarification regarding when 4,0 mm diameter electrodes are not manufactured;
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.

v
ISO 18275:2026(en)
Introduction
This document recognizes that there are two somewhat different approaches in the global market to
classifying a given electrode, and allows for either or both to be used, to suit a particular market need.
Application of either type of classification designation (or of both, where suitable) identifies a product as
classified in accordance with this document. The classification in accordance with system A was originally
based on EN 757:1997 which has been withdrawn and replaced by this document. The classification in
accordance with system B is mainly based on standards used around the Pacific Rim.
This document provides a classification system for covered electrodes for high-strength steels in terms
of the tensile properties, impact properties and chemical composition of the all-weld metal, as well as the
type of electrode covering. The ratio of yield strength to tensile strength of weld metal is generally higher
than that of parent metal. Users should note that matching weld metal yield strength to parent metal yield
strength does not necessarily ensure that the weld metal tensile strength matches that of the parent metal.
Therefore, where the application requires matching tensile strength, selection of the consumable should be
made by reference to column 3 (Tensile strength) of Table 3 or column 2 (Tensile strength) of Table 11.
The mechanical properties of all-weld metal test specimens used to classify covered electrodes can vary
from those obtained in production joints because of differences in welding procedure such as electrode size,
width of weave, welding position, and parent metal composition.

vi
International Standard ISO 18275:2026(en)
Welding consumables — Covered electrodes for manual metal
arc welding of high-strength steels — Classification
1 Scope
This document specifies requirements for classification of covered electrodes and deposited metal in the as-
welded condition and in the post-weld heat-treated condition for manual metal arc welding of high-strength
steels with a minimum yield strength greater than 500 MPa or a minimum tensile strength greater than
570 MPa.
This document is a combined specification providing a classification utilizing a system based on the yield
strength and an average impact energy of 47 J of the all-weld metal, or utilizing a system based on the tensile
strength and an average impact energy of 27 J of the all-weld metal.
a) Clauses, subclauses and tables which carry the suffix “System A” are applicable only to covered
electrodes classified under the system based on the yield strength and an average impact energy of 47 J
of the all-weld metal given in this document.
b) Clauses, subclauses and tables which carry the suffix “System B” are applicable only to covered
electrodes classified under the system based on the tensile strength and an average impact energy of
27 J of the all-weld metal given in this document.
c) Subclauses and tables which do not have either the suffix “System A” or the suffix “System B” are
applicable to all covered electrodes classified under this document.
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 544, Welding consumables — Technical delivery conditions for filler materials and fluxes — Type of product,
dimensions, tolerances and markings
ISO 2401:2018, Welding consumables — Covered electrodes — Determination of the efficiency, metal recovery
and deposition coefficient
ISO 2560:2020, Welding consumables — Covered electrodes for manual metal arc welding of non-alloy and fine
grain steels — Classification
ISO 3690, Welding and allied processes — Determination of hydrogen content in arc weld metal
ISO 6847, Welding consumables — Deposition of a weld metal pad for chemical analysis
ISO 6947, Welding and allied processes — Welding positions
ISO 14344, Welding consumables — Procurement of filler materials and fluxes
ISO 15792-1:2020, Welding consumables — Test methods — Part 1: Preparation of all-weld metal test pieces
and specimens in steel, nickel and nickel alloys
ISO 80000-1:2022, Quantities and units — Part 1: General

ISO 18275:2026(en)
3 Terms and definitions
No terms and definitions are listed in this document.
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/
4 Classification
4.1 General
Classification designations are based on two approaches, A and B, to indicate the tensile properties, and the
impact properties of the all-weld metal obtained with a given electrode.
System A is applicable to covered electrodes classified under the system based on the yield strength and an
average impact energy of 47 J of the all-weld metal given in this document.
System B is applicable to covered electrodes classified under the system based on the tensile strength and
an average impact energy of 27 J of the all-weld metal given in this document.
The two designation approaches include additional designators for some other classification requirements,
but not all, as will be clear from the following subclauses. In most cases, a given commercial product can
be classified in both systems, in such cases, either or both classification designations can be used for the
product.
Annex A gives figures that explain how the classification systems are structured.
4.2 Classification systems
Each classification system is split into parts as given in Table 1.
The classifications are based on an electrode diameter of 4,0 mm.
Table 1 — Parts of each classification system
Part of classifi- Classification system
cation designa-
System A System B
tion
1 symbol indicating the product/process to be identified
symbol indicating the strength and elongation of symbol indicating the strength of the all-weld
the all-weld metal (See Table 3) metal (See Table 3)
symbol indicating the impact properties of the symbol indicating the type of electrode cover-
3 all-weld metal (See Table 4) ing, the type of current, and the welding position
(See Table 7)
symbol indicating the chemical composition of symbol indicating the chemical composition of
the all-weld metal (See Table 5) the all-weld metal (See Table 6)
symbol indicating the type of electrode covering symbol indicating the condition of the post-weld
5 (See 5.5.1) heat treatment under which the all-weld metal
test was conducted (See 5.6.2)
symbol indicating post-weld heat treatment if symbol indicating that the electrode has satis-
this is applied (See 5.6.1) fied a requirement for 47 J impact energy at the
temperature normally used for the 27 J require-
ment (See 5.3.2)
ISO 18275:2026(en)
TTabablele 1 1 ((ccoonnttiinnueuedd))
Part of classifi- Classification system
cation designa-
System A System B
tion
symbol indicating the nominal electrode effi- symbol indicating the diffusible hydrogen con-
ciency and type of current (See Table 8) tent of the deposited metal (See Table 10)
symbol indicating the welding position (See —
Table 9)
symbol indicating the diffusible hydrogen con- —
tent of the deposited metal (See Table 10)
4.3 Compulsory and optional sections
4.3.1 General
In both systems, the electrode classification shall include all compulsory sections and may include optional
sections as outlined in Table 2.
The designation (see Clause 11) shall be used on packages and in the manufacturer's literature and data
sheets.
Figure A.1 gives a schematic representation of the designation of electrodes classified by yield strength and
47 J impact energy (system A). Figure A.2 gives a schematic representation of the designation of electrodes
classified by tensile strength and 27 J impact energy (system B).
Table 2 — Electrode classification – Compulsory and optional sections
Part of classifi- Classification system
cation designa-
System A System B
tion
includes the symbols for the type of product, the includes the symbols for the type of product, the
strength and elongation, the impact properties, strength, the type of covering (which includes
the chemical composition and the type of cover- the type of current and the welding position),
Compulsory
ing, i.e. the symbols defined in 5.1, 5.2.1, 5.3.1, the chemical composition and the condition of
5.4.1 and 5.5.1. heat treatment, i.e. the symbols defined in 5.1,
5.2.2, 5.4.2, 5.5.2, and 5.6.2
includes the symbols for post-weld heat treat- includes the symbol for the optional supple-
ment, the weld metal recovery, the type of mental designator for 47 J impact energy, i.e.
current, the welding positions for which the the symbol defined in 5.3.2, and the symbol for
Optional
electrode is suitable, and the symbol for diffusi- the diffusible hydrogen content, i.e. the symbol
ble hydrogen content, i.e. the symbols defined in defined in 5.9
5.6.1, 5.7.1, 5.8.1 and 5.9.
5 Symbols and requirements
5.1 Symbol for the product/process
The symbol for the covered electrode used in the manual metal arc process shall be the letter E.

ISO 18275:2026(en)
5.2 Symbol for tensile properties of all-weld metal
5.2.1 System A
The symbols in Table 3 indicate the yield strength, tensile strength and elongation of the all-weld metal in
the as-welded condition or, if a T is added to the designation, after post-weld heat treatment as described in
5.6.1, determined in accordance with Clause 6.
NOTE Post-weld heat treatment (sometimes referred to as stress relief heat treatment) can alter the mechanical
properties of the weld from those obtained in the as-welded condition.
5.2.2 System B
The symbols in Table 3 indicate the tensile strength of the all-weld metal in the as-welded condition, in
the post-weld heat-treated condition, or in both conditions, determined in accordance with Clause 6. The
yield strength and elongation requirements depend on the specific chemical composition, heat treatment
condition and covering type, as well as on the tensile strength requirements, as given for the complete
classification in Table 11.
Table 3 — Symbol for tensile properties of all-weld metal
Classification system
System A System B
Minimum tensile
Minimum Tensile Minimum
strength
b
yield strength elongation
Symbol Symbol
a
strength
MPa MPa %
MPa
55 550 610 to 780 18 59 590
62 620 690 to 890 18 62 620
69 690 760 to 960 17 69 690
79 790 880 to 16 76 760
1 080
89 890 980 to 15 78 780
1 180
96 960 ≥ 1 000 13 83 830
NOTE Post-weld heat treatment (sometimes referred to as stress relief heat treatment) can alter the mechanical
properties of the weld from those obtained in the as-welded condition
a
For yield strength, the lower yield strength (R ) shall be used when yielding occurs, otherwise the 0,2 % proof
eL
strength (R ) shall be used.
p0,2
b
The gauge length is equal to five times the test specimen diameter.
5.3 Symbol for impact properties of all-weld metal
5.3.1 System A
The symbols in Table 4 indicate the temperature at which an average impact energy of 47 J is achieved under
the conditions given in Clause 6. Three test specimens shall be tested. Only one individual value may be
lower than 47 J, but it shall not be lower than 32 J. When an all-weld metal has been classified for a certain
temperature, this automatically covers any higher temperature in Table 4.
5.3.2 System B
There is no specific symbol for impact properties. The complete classification in Table 11 determines the
temperature at which an impact energy of 27 J is achieved in the as-welded condition or in the post-weld
heat-treated condition under the conditions given in Clause 6. Five test specimens shall be tested. The lowest

ISO 18275:2026(en)
and highest values obtained shall be disregarded. Two of the three remaining values shall equal or exceed
the specified 27 J level, one of the three may be lower but shall not be less than 20 J. The average of the three
remaining values shall be at least 27 J.
The addition of the optional symbol U, immediately after the symbol for condition of heat treatment, indicates
that the supplemental requirement of 47 J impact energy at the normal 27 J impact test temperature has also
been satisfied. For the 47 J impact requirement, the number of specimens tested and values obtained shall
meet the requirements of 5.3.1.
Table 4 — System A symbols for impact properties of all-weld metal
Temperature for minimum
Symbol average impact energy 47 J
°C
Z No requirements
A + 20
0 0
2 – 20
3 – 30
4 – 40
5 – 50
6 – 60
7 – 70
8 – 80
5.4 Symbol for chemical composition of all-weld metal
5.4.1 System A
The symbols in Table 5 indicate the chemical composition of the all-weld metal, determined in accordance
with Clause 7.
Table 5 — System A symbols for chemical composition of all-weld metal
a,b
Alloy symbol Chemical composition
% (by mass)
Mn Ni Cr Mo
MnMo 1,4 to 2,0 — — 0,3 to 0,6
Mn1Ni 1,4 to 2,0 0,6 to 1,2 — —
1NiMo 1,4 0,6 to 1,2 — 0,3 to 0,6
1,5NiMo 1,4 1,2 to 1,8 — 0,3 to 0,6
2NiMo 1,4 1,8 to 2,6 — 0,3 to 0,6
Mn1NiMo 1,4 to 2,0 0,6 to 1,2 — 0,3 to 0,6
Mn2NiMo 1,4 to 2,0 1,8 to 2,6 — 0,3 to 0,6
Mn2NiCrMo 1,4 to 2,0 1,8 to 2,6 0,3 to 0,6 0,3 to 0,6
Mn2Ni1CrMo 1,4 to 2,0 1,8 to 2,6 0,6 to 1,0 0,3 to 0,6
c
Z Any other agreed composition
a
If not specified, Mo < 0,2; Ni < 0,3; Cr < 0,2; V < 0,05; Nb < 0,05; Cu < 0,3; 0,03 ≤ C ≤ 0,10; P < 0,025; S < 0,020; Si < 0,80.
b
Single values are maxima.
c
Consumables for which the chemical composition is not listed shall be symbolized similarly and prefixed by the letter Z.
The chemical composition ranges are not specified, and it is possible that two electrodes with the same Z classification are not
interchangeable.
ISO 18275:2026(en)
5.4.2 System B
The symbols in Table 6 indicate the principal alloying elements, and sometimes the nominal alloy level of the
most significant alloy element, of the all-weld metal, determined in accordance with Clause 7. The symbol
for chemical composition does not immediately follow the symbol for strength but follows the symbol for
covering type. The complete compulsory classification designation, given in 5.10.2 and Table 12, determines
the exact chemical composition requirements for a particular electrode classification.
Table 6 — System B symbols for chemical composition of all-weld metal
Alloy symbol Chemical composition
% (by mass)
Principal alloy element(s) Nominal level
Mn 1,5
3 M2
Mo 0,4
Mn 2,0
4 M2
Mo 0,4
Mn 1,5
3 M3
Mo 0,5
Ni 0,5
N1M1
Mo 0,2
Ni 1,0
N2M1
Mo 0,2
N3M1 Ni 1,5
Mo 0,2
N3M2 Ni 1,5
Mo 0,4
Ni 2,0
N4M1
Mo 0,2
Ni 2,0
N4M2
Mo 0,4
Ni 2,0
N4M3
Mo 0,5
Ni 2,5
N5M1
Mo 0,2
Ni 2,5
N5M4
Mo 0,6
Ni 4,5
N9M3
Mo 0,5
N13L Ni 6,5
Ni 1,5
N3CM1 Cr 0,2
Mo 0,2
Ni 1,8
N4CM2 Cr 0,3
Mo 0,4
a
Consumables for which the chemical composition is not listed shall be symbolized similarly and prefixed by the letter G.
The chemical composition ranges are not specified, and it is possible that two electrodes with the same G classification are not
interchangeable.
ISO 18275:2026(en)
TTabablele 6 6 ((ccoonnttiinnueuedd))
Alloy symbol Chemical composition
% (by mass)
Principal alloy element(s) Nominal level
Ni 2,0
N4C2M1 Cr 0,7
Mo 0,3
Ni 2,0
N4C2M2 Cr 1,0
Mo 0,4
Ni 2,5
N5CM3 Cr 0,3
Mo 0,5
Ni 3,0
N6M4
Mo 1,0
Ni 3,5
N7CM3 Cr 0,3
Mo 0,5
Mn 1,2
P1 Ni 1,0
Mo 0,5
Mn 1,3
P2 Ni 1,0
Mo 0,5
a
G Any other agreed composition
a
Consumables for which the chemical composition is not listed shall be symbolized similarly and prefixed by the letter G.
The chemical composition ranges are not specified, and it is possible that two electrodes with the same G classification are not
interchangeable.
5.5 Symbol for type of electrode covering
5.5.1 System A
Most electrodes of this type have a basic covering and the symbol for this shall be B.
Cellulosic and other electrode coverings shall be in accordance with ISO 2560:2020, 5.5A.
NOTE A description of the characteristics of each of the types of covering is given in Annex B.
5.5.2 System B
The type of covering of a covered electrode depends substantially on the types of slag-forming component.
The type of covering also determines the positions suitable for welding and the type of current, in accordance
with Table 7.
ISO 18275:2026(en)
Table 7 — System B symbols for type of covering
a b
Symbol Type of covering Welding positions Type of current
10 Cellulosic All DC (+)
11 Cellulosic All AC and DC (+)
c
13 Rutile All AC and DC (+)
c
15 Basic All DC (+)
c
16 Basic All AC and DC (+)
c
18 Basic + iron powder All AC and DC (+)
d
45 Basic All DC (+)
NOTE A description of the characteristics of each of the types of covering is given in Annex C.
a
The welding positions shall be in accordance with ISO 6947.
b
Alternating current = AC; direct current = DC; electrode positive = (+); electrode positive or electrode negative = (±).
c
The indication “all positions” may or may not include vertical down welding. This shall be specified in the manufacturer's
trade literature.
d
Excluding vertical up welding.
5.6 Symbol for condition of post-weld heat treatment of all-weld metal
5.6.1 System A
The letter T indicates that strength, elongation and impact properties in the classification of the deposited
metal are obtained after a post-weld heat treatment between 560 °C and 600 °C for 1 h (+10/−0 min). The
test piece shall be left in the furnace to cool down to 300 °C.
5.6.2 System B
If the electrode has been classified in the as-welded condition, the symbol A shall be added to the
classification. If the electrode has been classified in the post-weld heat-treated condition the post-weld heat
treatment shall be 620 °C ± 15 °C for 1 h (+15/−0 min) except for E6218-N4M2 P which shall be 8 h (± 10 min)
or 580 °C ± 15 °C for 1 h (+10/−0 min) in the case of chemical composition N13L, and the symbol P shall be
added to the classification. If the electrode has been classified in both conditions, the symbol AP shall be
added to the classification. See Table 12 for the use of A and P in specific classifications.
The furnace shall be at a temperature not higher than 300 °C when the test assembly is placed in it. The
heating rate, from that point to the specified holding temperature, shall not exceed 300 °C/h. When the
holding time has been completed, the assembly shall be allowed to cool in the furnace to a temperature below
300 °C at a rate not exceeding 200 °C/h. The assembly may be removed from the furnace at any temperature
below 300 °C and allowed to cool in still air to room temperature.
5.7 Symbol for electrode efficiency and type of current
5.7.1 System A
The symbols in Table 8 indicate the electrode efficiency that shall be determined in accordance with
ISO 2401:2018 with the type of current shown in Table 8.

ISO 18275:2026(en)
Table 8 — System A symbols for nominal electrode efficiency and type of current
Electrode efficiency
a
Symbol Type of current
%
1 ≤ 105 AC and DC
2 ≤ 105 DC
3 > 105 ≤ 125 AC and DC
4 > 105 ≤ 125 DC
5 > 125 ≤ 160 AC and DC
6 > 125 ≤ 160 DC
7 >160 AC and DC
8 >160 DC
a
If an electrode is suitable for both DC and AC operation, the electrode efficiency shall be based on AC testing only.
5.7.2 System B
There is no specific symbol for electrode efficiency and type of current. Type of current is included in the
symbol for type of covering (Table 7). Electrode efficiency is not addressed.
5.8 Symbol for welding position
5.8.1 System A
The symbols in Table 9 for welding positions indicate the positions for which the electrode is suitable.
Table 9 — System A symbols for welding position
Symbol Welding positions according to ISO 6947
1 PA, PB, PC, PD, PE, PF, PG
2 PA, PB, PC, PD, PE, PF
3 PA, PB
...