IEC 60404-8-6:2016

Magnetic materials - Part 8-6: Specifications for individual materials - Soft magnetic metallic materials

IEC 60404-8-6:2016 specifies the general requirements, magnetic properties, geometric characteristics and tolerances as well as inspection procedures for pure iron, silicon-iron, nickel-iron and cobalt-iron. The materials are in the form of bar, billet, sheet, strip or wire. The alloys covered correspond to those defined by classes A, C1, C2, E1 to E4 and F1 to F3 in IEC 60404-1. This edition includes the following significant technical changes with respect to the previous edition: Removal of Table 2b).

Matériaux magnétiques - Partie 8-6: Spécifications pour matériaux particuliers - Matériaux métalliques magnétiquement doux

L’IEC 60404-8-6:2016 spécifie les exigences générales, les propriétés magnétiques, les caractéristiques géométriques et leurs tolérances, ainsi que les modes de contrôle pour le fer pur, le fer-silicium, le fer-nickel et le fer-cobalt. Les matériaux se présentent sous forme de barres, billettes, tôles, bandes ou fils. Les alliages concernés correspondent à ceux définis par les classes A, C1, C2, E1 à E4 et F1 à F3 de l’IEC 60404-1. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: Suppression du Tableau 2b).

General Information

• Status: Published
• Publication Date: 07-Dec-2016
• ICS: 29.030 - Magnetic materials
• Technical Committee: TC 68 - Magnetic alloys and steels
• Drafting Committee: WG 4 - TC 68/WG 4
• Current Stage: PPUB - Publication issued
• Start Date: 08-Dec-2016
• Completion Date: 15-Feb-2017

Relations

• Revises: IEC 60404-8-6:1999/AMD1:2007 - Amendment 1 - Magnetic materials - Part 8-6: Specifications for individual materials - Soft magnetic metallic materials
• Effective Date: 05-Sep-2023
• Revises: IEC 60404-8-6:1999 - Magnetic materials - Part 8-6: Specifications for individual materials - Soft magnetic metallic materials
• Effective Date: 05-Sep-2023

IEC 60404-8-6:2016 Overview

IEC 60404-8-6:2016, published by the International Electrotechnical Commission (IEC), is an international standard that specifies technical requirements, inspection procedures, and classifications for soft magnetic metallic materials. This part of the IEC 60404 series focuses on pure iron, silicon-iron, nickel-iron, and cobalt-iron alloys typically used in electrical and electronic engineering. The materials covered are supplied in various forms such as bars, billets, sheets, strips, or wires.

The standard ensures consistent quality by defining general requirements, magnetic properties, geometric characteristics, dimensional tolerances, and testing methods. It aligns with alloy classes A, C1, C2, E1-E4, and F1-F3 as per IEC 60404-1 classification.

Key Topics in IEC 60404-8-6:2016

• Materials Covered

  • Pure iron (Class A)
  • Silicon-iron alloys (Classes C1 and C2)
  • Nickel-iron alloys (Classes E1 to E4)
  • Cobalt-iron alloys (Classes F1 to F3)

• Forms of Supply

  • Bars, billets, sheets, strips, wires

• Magnetic Properties and Tests

  • DC and AC magnetic property measurements
  • Minimum required permeability and coercivity values
  • Magnetic hysteresis characterization under standardized test conditions

• Geometric Characteristics and Tolerances

  • Thickness, width, flatness, edge camber for flat products
  • Diameter, straightness, dimensional precision for long products such as rods and wires

• Inspection and Testing Protocols

  • Sampling criteria depending on product form
  • Specific magnetic and dimensional testing requirements
  • Compliance verification and retesting procedures

• Chemical Composition and Production Processes

  • Defined chemical composition limits per alloy class
  • Requirements for production processing to ensure material quality

Practical Applications

IEC 60404-8-6:2016 is essential for industries and professionals involved in manufacturing and applying soft magnetic metallic materials in:

• Electrical Engineering
  Materials conforming to this standard are widely used in transformer cores, electric motors, inductors, and generators where high magnetic permeability and low core loss are crucial.

• Electronics Manufacturing
  Soft magnetic alloys specified help optimize component performance in sensors, magnetic shielding, and electromagnetic interference (EMI) suppression devices.

• Automotive and Aerospace
  Precision-defined magnetic materials per IEC 60404-8-6 ensure reliability in actuators, relays, and other soft magnetic components used in vehicle control systems.

• Research and Development
  Accurate material specifications and test methods support innovation in magnetic materials technology and improve performance evaluations.

Using this standard guarantees compatibility and interoperability of materials across global suppliers and end-users, supporting quality assurance and reducing product failure risks.

Related Standards

For a comprehensive understanding and application of magnetic materials, IEC 60404-8-6:2016 should be considered alongside related IEC standards, including:

• IEC 60404-1 - General classification of magnetic materials, providing alloy class definitions referenced in Part 8-6.
• IEC 60404-8-3, IEC 60404-8-4, IEC 60404-8-7 - Specifications for non-oriented and oriented silicon steels for power frequency applications.
• IEC 60404-8-10 - Specifications for magnetic materials mainly used in relays and coercivity-classified iron and steel products with broader dimensional tolerances.

Adhering to this suite of standards ensures materials meet end-use requirements across diverse magnetic applications and industries.

---

Keywords: IEC 60404-8-6, soft magnetic metallic materials, pure iron, silicon-iron alloys, nickel-iron alloys, cobalt-iron alloys, magnetic properties, magnetic materials standard, magnetic permeability, electrical engineering materials, magnetic testing, IEC magnetic standards.

Standards Content (Sample)

IEC 60404-8-6 ®
Edition 3.0 2016-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Magnetic materials –
Part 8-6: Specifications for individual materials – Soft magnetic metallic
materials
Matériaux magnétiques –
Partie 8-6: Spécifications pour matériaux particuliers – Matériaux métalliques
magnétiquement doux
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: [phone]
3, rue de Varembé Fax: [phone]
CH-1211 Geneva 20 [e-mail]
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing 20 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 15 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 65 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. collected from earlier publications of IEC TC 37, 77, 86 and

CISPR.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: [e-mail].
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Catalogue IEC - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
Application autonome pour consulter tous les renseignements
Le premier dictionnaire en ligne de termes électroniques et
bibliographiques sur les Normes internationales,
électriques. Il contient 20 000 termes et définitions en anglais
Spécifications techniques, Rapports techniques et autres
et en français, ainsi que les termes équivalents dans 15
documents de l'IEC. Disponible pour PC, Mac OS, tablettes
langues additionnelles. Egalement appelé Vocabulaire
Android et iPad.
Electrotechnique International (IEV) en ligne.

Recherche de publications IEC - www.iec.ch/searchpub
Glossaire IEC - std.iec.ch/glossary
65 000 entrées terminologiques électrotechniques, en anglais
La recherche avancée permet de trouver des publications IEC
en utilisant différents critères (numéro de référence, texte, et en français, extraites des articles Termes et Définitions des
comité d’études,…). Elle donne aussi des informations sur les publications IEC parues depuis 2002. Plus certaines entrées
projets et les publications remplacées ou retirées. antérieures extraites des publications des CE 37, 77, 86 et

CISPR de l'IEC.
IEC Just Published - webstore.iec.ch/justpublished

Service Clients - webstore.iec.ch/csc
Restez informé sur les nouvelles publications IEC. Just
Published détaille les nouvelles publications parues. Si vous désirez nous donner des commentaires sur cette
Disponible en ligne et aussi une fois par mois par email. publication ou si vous avez des questions contactez-nous:
[e-mail].
IEC 60404-8-6 ®
Edition 3.0 2016-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Magnetic materials –
Part 8-6: Specifications for individual materials – Soft magnetic metallic

materials
Matériaux magnétiques –
Partie 8-6: Spécifications pour matériaux particuliers – Matériaux métalliques

magnétiquement doux
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.030 ISBN 978-2-8322-3674-1

– 2 – IEC 60404-8-6:2016 © IEC 2016
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviations . 7
3.1 Terms and definitions . 7
3.2 Abbreviations for test specimens . 8
4 Classification . 8
4.1 General . 8
4.2 Alloy class A (irons) . 9
4.3 Alloy class C (silicon steels). 9
4.4 Alloy class E (nickel-iron alloys) . 9
4.5 Alloy class F (cobalt-iron alloys) . 9
5 Designation . 9
6 General requirements . 9
6.1 Chemical composition and production process . 9
6.2 Delivery condition . 10
6.2.1 General . 10
6.2.2 Form of supply . 10
6.2.3 Surface condition . 10
7 Technical requirements . 10
7.1 Magnetic properties . 10
7.2 Geometric characteristics and tolerances . 11
7.2.1 Flat products: sheet, plate and strip . 11
7.2.2 Cold-worked bar, rod and wire . 11
7.2.3 Hot-finished bar . 11
8 Inspection and testing . 11
8.1 General . 11
8.2 Selection of samples . 12
8.2.1 General . 12
8.2.2 Flat products . 12
8.2.3 Long products . 12
8.2.4 Wire. 12
8.3 Magnetic properties . 12
8.3.1 Magnetic testing, DC measurements . 12
8.3.2 Magnetic testing, AC measurements . 12
8.3.3 Test specimens . 12
8.4 Geometric characteristics and tolerances . 12
8.4.1 Thickness of flat products . 12
8.4.2 Width of flat products . 12
8.4.3 Flatness . 12
8.4.4 Edge camber . 13
8.4.5 Dimensions of long products . 13
8.4.6 Straightness of long products . 13
8.5 Retests . 13
9 Complaints . 13
10 Ordering information . 13

11 Certification . 13
Bibliography . 20

Table 1 – Chemical composition of the alloy classes in accordance with IEC 60404-1 . 14
Table 2 – Minimum amplitude permeability requirements for sheet and strip – AC
measurement (50 Hz or 60 Hz), sine flux conditions, thickness 0,05 mm to 0,38 mm . 15
Table 3 – DC magnetic property requirements for bar, billet, rod, sheet, strip and wire,
thickness or diameter greater than 0,05 mm – S.R., L.R. or E.S. specimen . 16
Table 4 – Maximum permeability rise factor for sheet and strip – L.R. test specimen,
AC measurement (50 Hz or 60 Hz) . 17
Table 5 – Dimensional requirements for toroidal strip-wound cores . 17
Table 6 – Tolerances on thickness of cold-rolled sheet and strip . 18
Table 7 – Tolerances on width of sheet and strip . 18
Table 8 – Tolerances on dimensions of cold-worked bar, rod and wire . 19

– 4 – IEC 60404-8-6:2016 © IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MAGNETIC MATERIALS –
Part 8-6: Specifications for individual materials –
Soft magnetic metallic materials

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60404-8-6 has been prepared by IEC technical committee 68:
Magnetic alloys and steels.
This third edition cancels and replaces the second edition published in 1999 and
Amendment 1:2007. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
Removal of Table 2b).
The text of this standard is based on the following documents:
CDV Report on voting
68/528/CDV 68/552/RVC
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60404 series, published under the general title Magnetic
materials, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 60404-8-6:2016 © IEC 2016
MAGNETIC MATERIALS –
Part 8-6: Specifications for individual materials –
Soft magnetic metallic materials

1 Scope
This part of IEC 60404 specifies the general requirements, magnetic properties, geometric
characteristics and tolerances as well as inspection procedures for pure iron, silicon-iron,
nickel-iron and cobalt-iron. The materials are in the form of bar, billet, sheet, strip or wire. The
alloys covered correspond to those defined by classes A, C1, C2, E1 to E4 and F1 to F3 in
IEC 60404-1.
Magnetic materials used primarily for relays, iron and steel products, classified only by
coercivity, are covered in IEC 60404-8-10. IEC 60404-8-10 is less restrictive in terms of
magnetic properties than the irons (class A) and the silicon steels (classes C21 and C22)
specified in this standard, but it gives more comprehensive dimensional tolerances.
Non-oriented and oriented silicon steels (C21 and C22) for industrial power frequency
applications, classified by specific total loss, are covered in IEC 60404-8-3, IEC 60404-8-4
and IEC 60404-8-7.
Non-oriented and oriented thin magnetic materials for use at medium frequencies, classified
by specific total loss, are covered in IEC 60404-8-8.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60050-121, International Electrotechnical Vocabulary – Part 121: Electromagnetism
IEC 60050-131, International Electrotechnical Vocabulary – Part 131: Circuit theory
IEC 60050-221, International Electrotechnical Vocabulary – Chapter 221: Magnetic materials
and components
IEC 60404-1, Magnetic materials – Part 1: Classification
IEC 60404-2, Magnetic materials – Part 2: Methods of measurement of the magnetic
properties of electrical steel sheet and strip by means of an Epstein frame
IEC 60404-4, Magnetic materials – Part 4: Methods of measurement of d.c. magnetic
properties of iron and steel
IEC 60404-6, Magnetic materials – Part 6: Methods of measurement of the magnetic
properties of magnetically soft metallic and powder materials at frequencies in the range
20 Hz to 200 kHz by the use of ring specimens

IEC 60404-7, Magnetic materials – Part 7: Method of measurement of the coercivity of
magnetic materials in an open magnetic circuit
IEC 60404-8-3, Magnetic materials − Part 8-3: Specifications for individual materials − Cold-
rolled electrical non-alloyed and alloyed steel sheet and strip delivered in the semi-processed
state
IEC 60404-8-4, Magnetic materials – Part 8-4: Specifications for individual materials – Cold-
rolled non-oriented electrical steel strip and sheet delivered in the fully-processed state
IEC 60404-8-7, Magnetic materials – Part 8-7: Specifications for individual materials – Cold-
rolled grain-oriented electrical steel strip and sheet delivered in the fully-processed state
IEC 60404-8-8, Magnetic materials – Part 8: Specifications for individual materials –
Section 8: Specification for thin magnetic steel strip for use at medium frequencies
IEC 60404-8-10, Magnetic materials – Part 8-10: Specifications for individual materials –
Magnetic materials (iron and steel) for use in relays
IEC 60404-9, Magnetic materials – Part 9: Methods of determination of the geometrical
characteristics of magnetic steel sheet and strip
IEC 60635, Toroidal strip-wound cores made of magnetically soft material
ISO 404, Steel and steel products – General technical delivery requirements
ISO 10474, Steel and steel products – Inspection documents
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purpose of this document, the terms and definitions given in IEC 60050-121,
IEC 60050-131, IEC 60050-221 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
bar
solid product of uniform cross-section supplied in straight lengths
Note 1 to entry: The cross-section can be round, square, rectangular or regular polygonal.
Note 2 to entry: Flat: A bar of rectangular cross-section, rolled on the four faces, whose thickness is generally
5 mm or greater and whose width is not greater than 150 mm.
Note 3 to entry: Round: A bar of circular cross-section whose diameter is generally 8 mm or greater.
3.1.2
billet
solid product of uniform cross-section, which may be square, round or rectangular, with a
width less than twice the thickness

– 8 – IEC 60404-8-6:2016 © IEC 2016
3.1.3
heat
product of a furnace melt or of a number of melts that are mixed prior to casting
3.1.4
lot
material from the same heat, of the same form, produced at the same time and, if annealed,
heat-treated together or sequentially in a continuous furnace
3.1.5
rod
cold-drawn product of uniform rectangular or round cross-section, supplied in straight lengths
3.1.6
sheet and plate
flat-rolled product of uniform cross-section, supplied in coils or cut lengths where the width is
over 600 mm
Note 1 to entry: Sheets have a thickness under 5 mm and plates have a thickness over 5 mm.
3.1.7
straightness of long products
greatest distance between the bar and the line joining the two ends of the bar
3.1.8
strip
flat-rolled product of uniform cross-section, supplied in coils or cut lengths where the width is
under 600 mm and the thickness under 5 mm
3.1.9
wire
rolled or drawn product of uniform round or rectangular cross-section, supplied in coils
3.2 Abbreviations for test specimens
Type E.S.: Elongated specimen for test samples, of circular, rectangular or polygonal cross-
section, with a length to diameter ratio of at least 5/1, according to IEC 60404-7.
Type L.R.: Laminated rings stamped or etched from flat products (for magnetic head ring, a
core with 10 mm outside diameter and 6 mm inside diameter can be used).
Type S.R.: Solid rings or square frames, formed or machined from solid material. The outside
diameter of the ring shall be between 30 mm and 50 mm, with an outside/inside diameter ratio
from 1,2 to 1,4.
NOTE Types L.R. and S.R. are only applicable to essentially isotropic materials.
Type S.W.: Strip-wound cores as defined by IEC 60635. For dimensional restrictions, see
Table 5. The outside diameters of test cores are between 30 mm and 80 mm.
4 Classification
4.1 General
The materials covered by this document are classified according to the main alloying element
and the content of this element. The subclassification takes into account the different uses of
the alloys.
4.2 Alloy class A (irons)
This material is classified according to the maximum value of coercivity.
4.3 Alloy class C (silicon steels)
Alloy C1, in which the main alloying element is silicon with a content up to approximately 5 %
, is classified according to the maximum value of coercivity.
Alloys C2, in which the main alloying element is silicon with a content up to approximately
5 %, are classified according to the shape of the hysteresis loop and the minimum amplitude
permeability in an AC measurement (50 Hz or 60 Hz) with a L.R. specimen made of material

with a thickness of 0,35 mm; the measuring point is H = 1,6 A/m.
4.4 Alloy class E (nickel-iron alloys)
These alloys are classified according to the shape of the hysteresis loop and the minimum
amplitude permeability in an AC measurement (50 Hz or 60 Hz), under sine flux conditions,
with a S.W. specimen made of material with a thickness of 0,10 mm.
4.5 Alloy class F (cobalt-iron alloys)
These alloys are classified according to the shape of the hysteresis loop and to the maximum
value of coercivity.
5 Designation
The conventional designation of the materials comprises the following in the order given:
a) the letter for the alloy class: A, C, E or F (see Table 1);
b) the number according to the content of the main alloying element (see Table 1);
c) for alloy classes C, E and F, the number 1 or 2 according to the shape of the hysteresis
loop:
1) = round (non-oriented)
2) = rectangular (oriented by texture or by thermomagnetic treatment);
d) a dash;
e) depending on the alloy class, either the maximum value for the coercivity in amperes per
metre or the peak value of the minimum permeability divided by 1 000 for a given

magnetic field strength ( H = 0,4 A/m or 1,6 A/m) and a given thickness measured with a
certain test specimen (see above under classification).
EXAMPLE:
E31-10: nickel-iron with 40 % to 51 % weight of nickel, a round hysteresis loop, and a minimum amplitude
ˆ
permeability of 10 000 at the peak value of the magnetic field strength H of 0,4 A/m at 50 Hz or 60 Hz for a strip-
wound core made of a sheet with a thickness of 0,10 mm.
6 General requirements
6.1 Chemical composition and production process
The typical composition of each of the alloy classes covered by this document is given in
Table 1.
The actual composition and production process are left to the discretion of the manufacturer,
unless otherwise agreed between the manufacturer and purchaser, and specified in the order.

– 10 – IEC 60404-8-6:2016 © IEC 2016
6.2 Delivery condition
6.2.1 General
The materials covered by this standard may be delivered in the hot-finished, cold-worked or
annealed condition. The condition required shall be specified in the order.
6.2.2 Form of supply
Coils shall be of constant width and wound in such a manner that the edges are
superimposed in a regular manner and the side faces of the coil are substantially flat. Coils
shall be sufficiently tightly wound that they do not collapse under their own weight.
Coils can occasionally present welds or interleaves resulting from the removal of defective
zones, subject to prior agreement between the parties. The value of the additional thickness
due to the weld is subject to special agreement. If necessary, the marking of welds or
interleaves may form the subject of a special agreement. For coils containing repair welds or
interleaves, each part of the strip shall be of the same quality material.
The edges of parts welded together shall not be so much out of alignment as to affect the
further processing of the material.
The mass of coils shall be agreed upon at the time of ordering.
6.2.3 Surface condition
The surface condition of sheets or strips shall be uniform, clean, and free from grease and
rust.
Isolated imperfections such as scratches, blisters, etc. may be tolerated if the thickness
remains within the tolerance limits and the manufacture or performance of the final product is
not affected.
The nature of the surface condition will depend on the final treatment. For material in the hot-
finished condition, the material exhibits a hot mill scale.
7 Technical requirements
7.1 Magnetic properties
Unless otherwise required by the order, the magnetic properties shall be determined for each
lot of material on a representative sample taken from the lot and heat-treated in accordance
with the recommendations of the manufacturer or as specified by the purchaser. Acceptance
testing of sheets and strips shall be carried out by AC measurement of laminated rings (type
L.R.) or strip-wound cores (type S.W.), or by DC measurement of either solid rings (type
S.R.), laminated rings (type L.R.) or elongated specimens (type E.S.).
The properties shall meet the magnetic requirements specified in Tables 2 to 4 for the alloy,
the magnetic grade and the thickness specified in the order. For intermediate thicknesses not
given in the tables, the values for the next thicker group shall apply. It is not necessary to
measure all of the properties. The required magnetic properties and test conditions shall be
agreed between manufacturer and purchaser.

7.2 Geometric characteristics and tolerances
7.2.1 Flat products: sheet, plate and strip
7.2.1.1 Thickness
The thickness of cold-rolled sheet and strip shall not vary by more than the tolerances
indicated in Table 6.
7.2.1.2 Width
The width of strip shall not vary by more than the tolerances indicated in Table 7.
7.2.1.3 Flatness
The wave factor, expressed as a percentage, shall not exceed 2 % and flatness shall be as
agreed between manufacturer and purchaser.
7.2.1.4 Edge camber
The edge camber shall be as agreed between the manufacturer and the purchaser.
7.2.2 Cold-worked bar, rod and wire
The diameter, width and thickness tolerances shall be as specified in Table 8.
7.2.3 Hot-finished bar
Tolerances shall be as agreed between the manufacturer and the purchaser.
8 Inspection and testing
8.1 General
The materials defined by this standard are generally ordered with inspection in accordance
with ISO 404. The purchaser shall specify, when ordering, the properties for which the
verification shall be made, the type of inspection and the related document (see ISO 10474).
In the case of an order without inspection, as a dispensation from ISO 404, the manufacturer
and the purchaser shall agree which property shall be certified, for example the maximum
coercivity of the delivered material.
Each acceptance unit shall comprise not more than 23 t of the same grade and the same
nominal dimensions. Different acceptance units can be adopted by special agreement.
For products supplied in coil form, each coil shall constitute an acceptance unit.
When the products are delivered in the form of slit coils, the test results applying to the parent
unit of acceptance shall apply.
Except by special agreement, the same rules apply to the characteristics which are
specifically specified.
– 12 – IEC 60404-8-6:2016 © IEC 2016
8.2 Selection of samples
8.2.1 General
As far as possible only one sample for acceptance inspection shall be taken from each
acceptance unit. The same sample shall serve to check the various properties by choosing a
suitable order for the execution of the tests.
8.2.2 Flat products
In the case of coils, the first internal turn and the last external turn shall be regarded as
wrapping and not as representative of the quality of the rest of the coil. The selection shall be
made from the first internal or external turns, excluding the wrapping turn. The selection shall
be made away from weld zones or interleaves. In the case of sheets or plates, the sample
shall be taken from the upper part of the bundle.
8.2.3 Long products
The sample shall be taken from the bundle.
8.2.4 Wire
The sampling shall be carried out at the end of the coil.
8.3 Magnetic properties
8.3.1 Magnetic testing, DC measurements
Measurement of DC magnetic polarization, permeability and coercivity shall be in accordance
with IEC 60404-4 and IEC 60404-7.
8.3.2 Magnetic testing, AC measurements
Measurement of AC magnetic polarization and amplitude permeability shall be in accordance
with IEC 60404-2 and IEC 60404-6. Unless otherwise specified, a test frequency of 50 Hz or
60 Hz shall be used. When amplitude permeability measurements are made, the test
conditions shall conform to sine flux (sine B).
8.3.3 Test specimens
The type of test specimens to be used for testing is indicated in Tables 2 to 4 by the
abbreviations for test specimens given in 3.2.
8.4 Geometric characteristics and tolerances
8.4.1 Thickness of flat products
The measurement of thickness shall be made at any point 10 mm or more from the edges,
except for widths less than 25 mm, which shall be measured at any point.
The measurement shall be made using a micrometer accurate to 1/100 mm.
8.4.2 Width of flat products
The width shall be measured perpendicularly to the longitudinal axis of the strip.
8.4.3 Flatness
The flatness (wave factor) of flat products shall be measured in accordance with IEC 60404-9.

8.4.4 Edge camber
The edge camber shall be determined in accordance with IEC 60404-9.
8.4.5 Dimensions of long products
The dimensions of long products shall be determined as the mean of readings taken at any
two points, with an accuracy of 0,1 mm.
8.4.6 Straightness of long products
The straightness shall be measured with an accuracy of 0,1 mm.
8.5 Retests
If a test specimen fails to meet the specified requirements, two further test specimens from
the same lot shall be selected for testing. If both of the additional samples pass, the lot is
regarded as complying with the requirements of this standard. If either of the further test
specimens fails, the lot shall be rejected.
The producer has the right, after retreatment, to present again for test acceptance those units
which had been found not to comply with the order.
9 Complaints
Internal or external defects shall justify a complaint only if they are clearly prejudicial to the
method of working or the judicious use of the material.
The user shall give the supplier the opportunity of convincing himself of the fairness of the
claim by presenting the material in dispute and evidence for the complaint.
In all cases, the terms and conditions of complaint shall be in accordance with ISO 404.
10 Ordering information
For material to comply adequately with the requirements of this standard, the purchaser shall
include the following information in his enquiry or order:
a) nature of the product and the designation of the material in accordance with Clause 5;
b) quantity required, including any limitations on the mass of coils (see 6.2.2);
c) inspection procedure required, including the nature of the related documents (see 8.1 and
Clause 11);
d) type of tolerances when necessary (see 7.2);
e) the following additional requirements, which shall be specified by the purchaser at the
time of order; in the case where nothing is specified, the producer shall consider that
there are no particular requirements on this point:
– presence of welds or interleaves, and their possible marking (see 6.2),
– delivery of materials in the fully processed condition (see 6.2).
11 Certification
When required by the purchaser and stated in the order (see Clause 10), the manufacturer
shall certify that the material has been manufactured and tested in accordance with the
requirements of this standard. The certificate shall detail the results of all tests required by
the order.
– 14 – IEC 60404-8-6:2016 © IEC 2016
Table 1 – Chemical composition of the alloy classes in accordance with IEC 60404-1
a
Typical compositions
Constituents in
Alloy
Mass fraction in %
accordance with
class
IEC 60404-1
Co Cr Cu Mo Ni Si V
A 100 Fe – – – – – – –
C1 ≤ 5 Si – – – – – 2 – 4,5 –
C21 ≤ 5 Si – – – – – 1 – 4,5 –
C22 approx. 3 Si – – – – – 2,5 – 3,5 –
– 2 – 3 1 – 6 – 75 – 80 – –
E1 70 – 85 Ni – – 1 – 6 3 – 5 75 – 80 – –
– – – 3,5 – 6,5 79 – 82 – –
E2 54 – 68 Ni – – – – 53 – 65 – –
E3 40 – 51 Ni – – – – 42 – 50 – –
E4 35 – 40 Ni – – – – 36 – 40 – –
F1 47 – 50 Co 47,5 – 50 – – – – – 1,7 – 2,5
F2 35 Co 34,5 – 36 – – – – – –
F3 23 –28 Co 23 – 28 – – – – – –
Typical compositions of each alloy class are shown as examples and other compositions are acceptable if the
magnetic property requirements in this standard are satisfied.
a
Remainder: iron.
Table 2 – Minimum amplitude permeability requirements for sheet and strip –
AC measurement (50 Hz or 60 Hz), sine flux conditions, thickness 0,05 mm to 0,38 mm
Alloy Magnetic Measuring Specimen Minimum amplitude permeability
a
class grade point for a thickness, in millimetres, of
ˆ
H(A / m)
0,35 0,20
A As agreed between manufacturer and purchaser
C1 As agreed between manufacturer and purchaser
C21 –9 900 750
1,6 L.R.
C22 –13 1 300 -–
Alloy Magnetic Measuring Specimen Minimum amplitude permeability
a
class grade point for a thickness, in millimetres, of
ˆ
H(A / m)
0,30 – 0,38 0,15 – 0,20 0,10 0,05
–30 20 000 20 000 18 000 16 000
–60 40 000 40 000 35 000 30 000
E11 0,4
–100 50 000 60 000 60 000 50 000
–200 80 000 100 000 100 000 100 000
–4 L.R. 4 000 4 000 4 000 4 000
E31 –6 0,4 6 000 6 000 6 000 6 000
–10 10 000 10 000 8 000 8 000
–2 2 200 2 200 2 200 2 200
E41 0,8
–3 2 900 2 900 2 900 2 500
–30 b 30 000 30 000 30 000
–60 b 60 000 60 000 60 000
E11 0,4
–100 b 80 000 100 000 100 000
–200 b 160 000 200 000 200 000
–4 S.W. b 4 000 4 000 4 000
E31 –6 0,4 b 6 000 6 000 6 000
–10 b 10 000 10 000 10 000
–2 b 2 200 2 200 2 200
E41 0,8
–3 b 2 900 2 900 2 500
E21
As agreed between the manufacturer and the purchaser
E32
F1
F2 As agreed between the manufacturer and the purchaser
F3
a
The second digit of the alloy class stands for the shape of the hysteresis loop:
1 = round (non-oriented);
2 = rectangular (oriented).
b
Type S.W. should not be used in this thickness range.

– 16 – IEC 60404-8-6:2016 © IEC 2016
Table 3 – DC magnetic property requirements for bar, billet, rod, sheet, strip and wire,
a
thickness or diameter greater than 0,05 mm – S.R., L.R. or E.S. specimen
Minimum magnetic polarization in teslas
Maximum
Alloy Magnetic ˆ
for in amperes per metre
H
coercivity
b
class grade
A/m
100 200 300 500 1 000 4 000
A –240 240 – – 1,15 1,30 – 1,60
–120 120 – – 1,15 1,30 1,45 1,60
–80 80 – 1,10 1,20 1,30 1,45 1,60
–60 60 – 1,15 1,25 1,35 1,45 1,60
–20 20 1,15 1,25 1,30 1,40 1,45 1,60
–12 12 1,15 1,25 1,30 1,40 1,45 1,60
C1 –48 48 0,60 – 1,10 1,20 – 1,50
–24 24 1,20 – 1,30 1,35 – 1,50
–12 12 1,20 – 1,30 1,35 – 1,50
Maximum
Measuring Minimum coercivity in
Minimum magnetic polarization in
Alloy Magnetic permeability for amperes per
ˆ
point
H
b
class grade a thickness, in metre for a ˆ
teslas for H in amperes per metre
A/m millimetres, of thickness, in
millimetres, of
0,05-1,5 >1,5 0,05-1,5 >1,5 20 50 100 500 800
–30 30 000 15 000 4 4
0,40 0,55 0,60 0,63 0,65
E11 –60 0,4 60 000 30 000 2 4
–100 100 000 50 000 1 2 0,50 0,65 0,70 0,73 0,73
–4 4 000 3 000 12 12
0,50 0,90 1,00 1,30 1,40
E31 –6 0,4 6 000 5 000 10 10
–10 10 000 7 000 6 6 0,50 0,90 1,10 1,35 1,40
E41 –3 0,8 2 500 2 500 24 24 0,20 0,45 0,70 1,00 1,10
E21
As agreed between the manufacturer and the purchaser
E32
Minimum magnetic polarization in teslas
Maximum
Alloy Magnetic Dimensions
ˆ
for in amperes per metre
H
Supplied form coercivity
b
class grade mm
A/m
300 800 1 600 2 800 4 000 8 000
c
Bulk material 240 1,40 1,70 1,90 2,00 2,06 2,15
–240
> 6
hot-rolled
Rod, wire d ≤ 6 120 1,70 2,00 2,10 2,15 2,20 2,25
F11
–120
Sheet, strip 0,05 ≤ t ≤2,0 120 – – – – – –
–60 Sheet, strip 60 1,80 2,10 2,20 2,23 2,25 2,25
0,05 ≤ t ≤2,0
S.W. 30 As agreed between the manufacturer and the
F12 –30 0,05 ≤ t ≤1,5
purchaser
c
Bulk material 300 – 1,20 1,30 1,35 – –
> 6
F21 –300
Sheet, strip 0,05 ≤ t ≤2,0 300 – 1,50 1,60 1,80 2,00 2,20

c
Bulk material 300 – – – – 1,10 1,75
> 6
F31 –300
Sheet, strip 300 – – – – 1,85 2,00
0,05 ≤ t ≤2,0
a
The properties for 0,05 mm to 2 mm thicknesses refer to sheet and strip only. For bar, billet, rod and wire with
small cross-sections, magnetic polarization shall be determined on S.R. specimens taken at an earlier stage
of manufacture.
b
The second digit of the alloy class stands for the shape of the hysteresis loop:
1 = round (non-oriented);
2 = rectangular (oriented by texture or thermomagnetic treatment).
c
Bulk materials comprise all type of hot rolled or hot forged materials. Cold rolled strips and sheets and cold-
worked wires are not included.

Table 4 – Maximum permeability rise factor for sheet and strip –
L.R. test specimen, AC measurement (50 Hz or 60 Hz)
a b
δ δ
0,4 8
Alloy class Magnetic grade
–2 –2
10 m/A 10 m/A
E41 –2 4,7 3,1
C21 –9 – 15,7
C22 –13 – 15,7
a
δ = (m −m ) /(m ⋅∆H)= 0,833(m −m ) /m (m/A)
0,4 1,6 0,4 0,4 1,6 0,4 0,4
b
δ = (m −m ) /(m ⋅∆H)= 0,156(m −m ) /m (m/A)
8 8 1,6 1,6 8 1,6 1,6
The indices denote the field strength, in amperes per metre (A/m).

Table 5 – Dimensional requirements for toroidal strip-wound cores
Alloy class
Ratio of dimensions
E11 – E41 E32
Outside/inside diameter (d /d ) 1,2 – 1,6 1,2 – 1,6
1 2
Height/inside diameter (h/d ) 0,2 – 1,1 0,2 – 1,1
Inside diameter/strip thickness (d /t)
> 100 > 100
– 18 – IEC 60404-8-6:2016 © IEC 2016
Table 6 – Tolerances on thickness of cold-rolled sheet and strip
a)
Thickness (t) Tolerance in millimetres for nominal width w in millimetres
mm
50 < w < 150 150 < w ≤ 300 300 < w ≤ 600 w > 600
0,05 ≤ t < 0,15 ±5 % ±5 % ±7,5 % ±10 %
0,15 ≤ t < 0,25 ±0,020 ±0,020 ±0,025 ±0,030
0,25 ≤ t < 0,50 ±0,025 ±0,030 ±0,030 ±0,040
0,50 ≤ t < 0,75 ±0,030 ±0,045 ±0,045 ±0,050
0,75 ≤ t < 1,00
±0,030 ±0,045 ±0,045 ±0,065
1,00 ≤ t < 1,25 ±0,040 ±0,045 ±0,045 ±0,065
1,25 ≤ t < 1,50 ±0,040 ±0,045 ±0,045 ±0,075
1,50 ≤ t < 1,75 ±0,040 ±0,050 ±0,065 ±0,075
1,75 ≤ t < 2,00 ±0,040 ±0,050 ±0,065 ±0,090
2,00 ≤ t < 2,25 ±0,050 ±0,055 ±0,065 ±0,100
2,25 ≤ t < 2,50 ±0,050 ±0,055 ±0,065 ±0,120
a)
For thicknesses equal to or greater than 0,05 mm and smaller
...