EN IEC 60404-12:2023

Magnetic materials - Part 12: Methods of test for the assessment of the thermal endurance of surface insulation coatings on electrical steel strip and sheet

IEC 60404-12:2023 is applicable to surface insulation coatings on electrical steel strip and sheet classified in IEC 60404-1-1. This document defines the general principles and technical details of the tests for the assessment of the thermal endurance of surface insulation coatings on electrical steel strip and sheet. The assessment is made by evaluating the change of a specified property of the surface insulation coating due to a heat treatment at a specified temperature up to 850 °C for a specified duration time up to 2 500 h. The specified property is measured at an ambient temperature of (23 ± 5) °C both without heat treatment and after heat treatment. This edition includes the following significant technical changes with respect to the previous edition:  the method of test for adhesion has been modified to match to the method of bend test specified in ISO 1519 using a cylindrical mandrel of 32 mm in diameter instead of the 30 mm diameter mandrel specified in the first edition; the method of test for interlaminar insulation resistance has been modified to match to the method specified in IEC 60404-11 and the modified Franklin test has been removed; the method of test for compressibility has been modified to match to the method of test for stacking factor specified in IEC 60404-13; the concept of "resistance grades" has been removed; the clamping pressure to be used at temperature ratings above 500 °C has been reduced to (0,01 ± 0,001) N/mm2; the testing for continuous exposure has been made a subject to an agreement between the manufacturer and the purchaser and the procedure has been moved to an informative Annex A.

Magnetische Werkstoffe - Teil 12: Prüfverfahren zur Bewertung der thermischen Beständigkeit von Oberflächenisolierbeschichtungen auf Elektroband und -blech

Matériaux magnétiques - Partie 12: Méthodes d’essai pour l'évaluation de l’endurance thermique des revêtements isolants superficiels des bandes et tôles en acier électrique

L’IEC 60404-12:2023 s'applique aux revêtements isolants superficiels des bandes et tôles en acier électrique classées dans l’IEC 60404-1-1. Le présent document définit les principes généraux et les éléments techniques des essais relatifs à l’évaluation de l’endurance thermique des revêtements isolants superficiels des bandes et tôles en acier électrique. L'évaluation consiste à apprécier la variation d’une propriété spécifiée du revêtement isolant superficiel du fait d’un traitement thermique à une température spécifiée allant jusqu’à 850 °C pendant une durée spécifiée maximale de 2 500 h. La propriété spécifiée est mesurée à une température ambiante de (23 ± 5) °C sans traitement thermique et après un traitement thermique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:  la méthode d'essai d’adhérence a été modifiée afin de correspondre à la méthode d’essai de pliage spécifiée dans l’ISO 1519, qui utilise un mandrin cylindrique d’un diamètre de 32 mm en lieu et place du mandrin d’un diamètre de 30 mm spécifié dans la première édition; la méthode d’essai de résistance d'isolation interlaminaire a été modifiée afin de correspondre à la méthode spécifiée dans l’IEC 60404-11 et l’essai de Franklin modifié a été supprimé; la méthode d’essai de compressibilité a été modifiée afin de correspondre à la méthode d’essai du facteur de foisonnement spécifiée dans l’IEC 60404-13; le concept de "niveaux de résistance" a été supprimé; la pression de serrage à utiliser à des températures assignées supérieures à 500 °C a été réduite à (0,01 ± 0,001) N/mm2; L’essai d’exposition continue a fait l’objet d’un accord entre le fabricant et l’acheteur et la procédure a été déplacée vers une Annexe A informative.

Magnetni materiali - 12. del: Metode preskušanja za oceno toplotne vzdržljivosti površinskih izolacijskih premazov na električnih jeklenih trakovih in pločevinah (IEC 60404-12:2023)

General Information

• Status: Published
• Publication Date: 23-Mar-2023
• ICS: 17.220.01 - Electricity. Magnetism. General aspects
• ICS: 29.030 - Magnetic materials
• Technical Committee: CLC/SR 68 - Magnetic alloys and steels
• Drafting Committee: IEC/TC 68 - IEC_TC_68
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 24-Mar-2023
• Completion Date: 24-Mar-2023
• Ref Project: SIST EN IEC 60404-12:2023 - Magnetic materials - Part 12: Methods of test for the assessment of the thermal endurance of surface insulation coatings on electrical steel strip and sheet (IEC 60404-12:2023)

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN IEC 60404-12:2023
01-maj-2023
Magnetni materiali - 12. del: Metode preskušanja za oceno toplotne vzdržljivosti
površinskih izolacijskih premazov na električnih jeklenih trakovih in pločevinah
(IEC 60404-12:2023)
Magnetic materials - Part 12: Methods of test for the assessment of the thermal

endurance of surface insulation coatings on electrical steel strip and sheet (IEC 60404-

12:2023)
Magnetische Werkstoffe - Teil 12: Prüfverfahren zur Bewertung der thermischen

Beständigkeit von Oberflächenisolierbeschichtungen auf Elektroband und -blech (IEC

60404-12:2023)

Matériaux magnétiques - Partie 12: Méthodes d’essai pour l'évaluation de l’endurance

thermique des revêtements isolants superficiels des bandes et tôles en acier électrique

(IEC 60404-12:2023)
Ta slovenski standard je istoveten z: EN IEC 60404-12:2023
ICS:
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
29.030 Magnetni materiali Magnetic materials
SIST EN IEC 60404-12:2023 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 60404-12:2023
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SIST EN IEC 60404-12:2023
EUROPEAN STANDARD EN IEC 60404-12
NORME EUROPÉENNE
EUROPÄISCHE NORM March 2023
ICS 29.030; 17.220.01
English Version
Magnetic materials - Part 12: Methods of test for the assessment
of the thermal endurance of surface insulation coatings on
electrical steel strip and sheet
(IEC 60404-12:2023)

Matériaux magnétiques - Partie 12: Méthodes d'essai pour Magnetische Werkstoffe - Teil 12: Prüfverfahren zur

l'évaluation de l'endurance thermique des revêtements Bewertung der thermischen Beständigkeit von

isolants superficiels des bandes et tôles en acier électrique Oberflächenisolierbeschichtungen auf Elektroband und -

(IEC 60404-12:2023) blech
(IEC 60404-12:2023)

This European Standard was approved by CENELEC on 2023-03-17. CENELEC 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 CENELEC 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 CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the

same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the

Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Türkiye and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 60404-12:2023 E
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SIST EN IEC 60404-12:2023
EN IEC 60404-12:2023 (E)
European foreword

The text of document 68/698/CDV, future edition 2 of IEC 60404-12, prepared by IEC/TC 68

"Magnetic alloys and steels" was submitted to the IEC-CENELEC parallel vote and approved by

CENELEC as EN IEC 60404-12:2023.
The following dates are fixed:

• latest date by which the document has to be implemented at national (dop) 2023-12-17

level by publication of an identical national standard or by endorsement

• latest date by which the national standards conflicting with the (dow) 2026-03-17

document have to be withdrawn

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Any feedback and questions on this document should be directed to the users’ national committee. A

complete listing of these bodies can be found on the CENELEC website.
Endorsement notice

The text of the International Standard IEC 60404-12:2023 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following note has to be added for the standard indicated:

IEC 60216-1 NOTE Approved as EN 60216-1
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SIST EN IEC 60404-12:2023
EN IEC 60404-12:2023 (E)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod),

the relevant EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available

here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60050-121 - International Electrotechnical Vocabulary - - -
Part 121: Electromagnetism
IEC 60050-221 - International Electrotechnical Vocabulary. - -
Chapter 221: Magnetic materials and
components
IEC 60404-1-1 - Magnetic materials - Part 1-1: - -
Classification - Surface insulations of
electrical steel sheet, strip and laminations
IEC 60404-11 - Magnetic materials - Part 11: Method of - -
test for the determination of surface
insulation resistance of magnetic sheet
and strip
IEC 60404-13 - Magnetic materials - Part 13: Methods of EN IEC 60404-13 -
measurement of resistivity, density and
stacking factor of electrical steel strip and
sheet
ISO 1519 - Paints and varnishes - Bend test EN ISO 1519 -
(cylindrical mandrel)
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SIST EN IEC 60404-12:2023
---------------------- Page: 6 ----------------------
SIST EN IEC 60404-12:2023
IEC 60404-12
Edition 2.0 2023-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Magnetic materials –
Part 12: Methods of test for the assessment of the thermal endurance of surface
insulation coatings on electrical steel strip and sheet
Matériaux magnétiques –
Partie 12: Méthodes d’essai pour l'évaluation de l’endurance thermique des
revêtements isolants superficiels des bandes et tôles en acier électrique
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220.01; 29.030 ISBN 978-2-8322-6445-4

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 7 ----------------------
SIST EN IEC 60404-12:2023
– 2 – IEC 60404-12:2023 © IEC 2023
CONTENTS

FOREWORD ........................................................................................................................... 3

INTRODUCTION ................................................................................................................... 5

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms and definitions ...................................................................................................... 7

4 General principles ........................................................................................................... 7

4.1 General ................................................................................................................... 7

4.2 Preparation of clamped stacks of test specimens .................................................... 7

4.2.1 Procedure of stacking test specimens .............................................................. 7

4.2.2 Clamping stacks for temperature ratings up to 500 °C ..................................... 7

4.2.3 Clamping stacks for temperature ratings above 500 °C .................................... 8

4.3 Heat treatment ........................................................................................................ 8

4.3.1 For time ratings up to 2 500 h .......................................................................... 8

4.3.2 For continuous exposure ................................................................................. 9

5 Standard temperature/time performance designations T/t ................................................ 9

6 Method of the test for adhesion ....................................................................................... 9

6.1 General ................................................................................................................... 9

6.2 Test specimens ....................................................................................................... 9

6.3 Procedure of test .................................................................................................... 9

6.4 Test report ............................................................................................................ 10

7 Method of the test for surface insulation resistance ....................................................... 10

7.1 General ................................................................................................................. 10

7.2 Test specimens ..................................................................................................... 10

7.3 Procedure of test .................................................................................................. 10

7.4 Test report ............................................................................................................ 11

8 Method of the test for stacking factor ............................................................................. 11

8.1 General ................................................................................................................. 11

8.2 Test specimen ...................................................................................................... 11

8.3 Procedure of test .................................................................................................. 11

8.4 Test report ............................................................................................................ 11

Annex A (informative) Method of test for the assessment of the thermal endurance for

continuous exposure to elevated temperatures ..................................................................... 12

A.1 General ................................................................................................................. 12

A.2 Procedure of test .................................................................................................. 12

A.3 Temperature/time performance designations T/t for continuous exposure ............. 12

Bibliography .......................................................................................................................... 13

Figure 1 – Example of clamped stack for 100 mm square test specimens ............................... 8

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SIST EN IEC 60404-12:2023
IEC 60404-12:2023 © IEC 2023 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MAGNETIC MATERIALS –
Part 12: Methods of test for the assessment of the thermal endurance
of surface insulation coatings on electrical steel strip and sheet
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.

IEC 60404-12 has been prepared by IEC technical committee 68: Magnetic alloys and steels.

It is an International Standard.

This second edition cancels and replaces the first edition published in 1992. This edition

constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:

a) the method of test for adhesion has been modified to match to the method of bend test

specified in ISO 1519 using a cylindrical mandrel of 32 mm in diameter instead of the 30 mm

diameter mandrel specified in the first edition;

b) the method of test for interlaminar insulation resistance has been modified to match to the

method specified in IEC 60404-11 and the modified Franklin test has been removed;

c) the method of test for compressibility has been modified to match to the method of test for

stacking factor specified in IEC 60404-13;
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SIST EN IEC 60404-12:2023
– 4 – IEC 60404-12:2023 © IEC 2023
d) the concept of "resistance grades" has been removed;

e) the clamping pressure to be used at temperature ratings above 500 °C has been reduced

to (0,01 ± 0,001) N/mm ;

f) the testing for continuous exposure has been made a subject to an agreement between the

manufacturer and the purchaser and the procedure has been moved to an informative

Annex A.
The text of this International Standard is based on the following documents:
Draft Report on voting
68/698/CDV 68/720/RVC

Full information on the voting for its approval can be found in the report on voting indicated in

the above table.
The language used for the development of this International Standard is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in

accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available

at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are

described in greater detail at www.iec.ch/publications.

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 document will remain unchanged until the

stability date indicated on the IEC website under webstore.iec.ch in the data related to the

specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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SIST EN IEC 60404-12:2023
IEC 60404-12:2023 © IEC 2023 – 5 –
INTRODUCTION

The surface insulation coatings on electrical steel strip and sheet are sometimes exposed to

elevated temperatures in service or during processing by the purchaser. Therefore, the thermal

endurance of the surface insulation coating is important.

Physicochemical models postulated for the aging processes lead to the almost universal

assumption of the Arrhenius equations to describe the rate of aging (see Annex A of this

document and IEC 60216-1).
Since the measurement of
...

SLOVENSKI STANDARD
oSIST prEN IEC 60404-12:2022
01-april-2022
Magnetni materiali - 12. del: Metode preskušanja za oceno toplotne vzdržljivosti
površinskih izolacijskih premazov na električnih jeklenih trakovih in pločevinah

Magnetic materials - Part 12: Methods of test for the assessment of thermal endurance

of surface insulation coatings on electrical steel strip and sheet

Matériaux magnétiques - Partie 12: Guide aux méthodes de caractérisation de la tenue

en température de l'isolation interlaminaire
Ta slovenski standard je istoveten z: prEN IEC 60404-12:2022
ICS:
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
29.030 Magnetni materiali Magnetic materials
oSIST prEN IEC 60404-12:2022 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN IEC 60404-12:2022
---------------------- Page: 2 ----------------------
oSIST prEN IEC 60404-12:2022
68/698/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 60404-12 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2022-01-21 2022-04-15
SUPERSEDES DOCUMENTS:
68/679/CD, 68/694/CC
IEC TC 68 : MAGNETIC ALLOYS AND STEELS
SECRETARIAT: SECRETARY:
Germany Mr Richard Daniel Knobloch
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:
Other TC/SCs are requested to indicate their interest, if
any, in this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY

SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING

Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft
for Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.

This document is still under study and subject to change. It should not be used for reference purposes.

Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of

which they are aware and to provide supporting documentation.
TITLE:

Magnetic materials - Part 12: Methods of test for the assessment of thermal endurance of

surface insulation coatings on electrical steel strip and sheet
PROPOSED STABILITY DATE: 2028
NOTE FROM TC/SC OFFICERS:

This document was prepared by the Project Leader together with the Project Team on the basis of the

second CD, 68/679/CD, and the related observations presented in 68/694/CC. The Chair decided to

proceed to the CDV according to the high degree of consensus achieved.

Copyright © 2021 International Electrotechnical Commission, IEC. All rights reserved. It is permitted to

download this electronic file, to make a copy and to print out the content for the sole purpose of preparing National

Committee positions. You may not copy or "mirror" the file or printed version of the document, or any part of it, for

any other purpose without permission in writing from IEC.
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oSIST prEN IEC 60404-12:2022
IEC CDV 60404-12 © IEC 2021 2 68/698/CDV
1 CONTENTS

3 FOREWORD ............................................................................................................... 3

4 INTRODUCTION ........................................................................................................ 5

5 1 Scope ................................................................................................................... 6

6 2 Normative references ........................................................................................... 6

7 3 Terms and definitions ........................................................................................... 7

8 4 General principles ................................................................................................ 7

9 4.1 General ........................................................................................................ 7

10 4.2 Preparation of clamped stacks of test specimens ......................................... 7

11 4.2.1 Procedure of stacking test specimens ................................................... 7

12 4.2.2 Clamping stacks for temperature ratings up to 500 °C .......................... 8

13 4.2.3 Clamping stacks for temperature ratings above 500 °C ......................... 8

14 4.3 Heat treatment ............................................................................................. 8

15 4.3.1 For time ratings up to 2 500 hours ........................................................ 8

16 4.3.2 For continuous exposure ...................................................................... 9

17 5 Standard temperature/time performance designations .......................................... 9

18 6 Method of the test for adhesion ............................................................................ 9

19 6.1 General ........................................................................................................ 9

20 6.2 Test specimens ............................................................................................ 9

21 6.3 Procedure of test ......................................................................................... 9

22 6.4 Test report ................................................................................................. 10

23 7 Method of the test for surface insulation resistance ............................................ 10

24 7.1 General ...................................................................................................... 10

25 7.2 Test specimens .......................................................................................... 10

26 7.3 Procedure of test ....................................................................................... 10

27 7.4 Test report ................................................................................................. 10

28 8 Method of the test for stacking factor .................................................................. 11

29 8.1 General ...................................................................................................... 11

30 8.2 Test specimen ........................................................................................... 11

31 8.3 Procedure of test ....................................................................................... 11

32 8.4 Test report ................................................................................................. 11

33 Annex A (informative) Method of test for the assessment of the thermal endurance for

34 continuous exposure to elevated temperatures ................................................... 12

35 A.1 General ...................................................................................................... 12

36 A.2 Test procedure ........................................................................................... 12

37 A.3 Temperature/time performance designations for continuous exposure ....... 12

38 Bibliography ............................................................................................................... 13

40 Figure 1 – Example of clamped stack for 100 mm square test specimens .................... 8

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oSIST prEN IEC 60404-12:2022
IEC CDV 60404-12 © IEC 2021 3 68/698/CDV
43 INTERNATIONAL ELECTROTECHNICAL COMMISSION
44 ___________
46 MAGNETIC MATERIALS –
48 Part 12: Methods of test for the assessment of the thermal endurance of
49 surface insulation coatings on electrical steel strip and sheet
52 FOREWORD

53 1) The IEC (International Electrotechnical Commission) is a world-wide organization for standardization

54 comprising all national electrotechnical committees (IEC National Committees). The object of the IEC is to

55 promote international cooperation on all questions concerning standardization in the electrical and electronic

56 fields. To this end and in addition to other activities, the IEC publishes International Standards, Technical

57 Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to

58 as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee

59 interested in the subject dealt with may participate in this preparatory work. International, governmental and

60 non-governmental organizations liaising with the IEC also participate in this preparation. The IEC collaborates

61 closely with the International Organization for Standardization (ISO) in accordance with conditions determined

62 by agreement between the two organizations.

63 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an

64 international consensus of opinion on the relevant subjects since each technical committee has representation

65 from all interested IEC National Committees.

66 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

67 Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

68 Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

69 misinterpretation by any end user.

70 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

71 transparently to the maximum extent possible in their national and regional publications. Any divergence

72 between any IEC Publication and the corresponding national or regional publication shall be clearly indicated

73 in the latter.

74 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

75 assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

76 services carried out by independent certification bodies.

77 6) All users should ensure that they have the latest edition of this publication.

78 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

79 members of its technical committees and IEC National Committees for any personal injury, property damage

80 or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

81 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

82 Publications.

83 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

84 indispensable for the correct application of this publication.

85 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

86 patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

87 IEC 60404-12 has been prepared by IEC technical committee 68: Magnetic alloys and steels.

88 It is an International Standard.

89 This second edition cancels and replaces the first edition published in 1992. This edition

90 constitutes a technical revision.

91 This edition includes the following significant technical changes with respect to the previous

92 edition:

93 a) the method of test for adhesion has been modified to match to the method of bend test

94 specified in ISO 1519:2011 using a cylindrical mandrel of 32 mm in diameter instead of the

95 30 mm diameter mandrel specified in the previous edition of this document;
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96 b) the method of test for interlaminar insulation resistance has been modified to match to the

97 method specified in IEC 60404-11 and the modified Franklin test has been removed;

98 c) the method of test for compressibility has been modified to match to the method of test for

99 stacking factor specified in IEC 60404-13;
100 d) the concept of “resistance grades” has been removed;

101 e) the clamping pressure to be used at temperature ratings above 500 °C has been reduced to

102 (0,01 ± 0,001) N/mm .

103 f) The testing for continuous exposure has been made a subject to an agreement between the

104 manufacturer and the purchaser and the procedure has been moved to an informative Annex

105 A.
106 The text of this International Standard is based on the following documents:
FDIS Report on voting
68/XX/FDIS 68/XX/RVD
107

108 Full information on the voting for the approval of this standard can be found in the Voting

109 Reports indicated in the above table.

110 The language used for the development of this International Standard is English.

111 This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in

112 accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available

113 at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are

114 described in greater detail at http://www.iec.ch/standardsdev/publications.

115 A list of all parts in the IEC 60404 series, published under the general title Magnetic materials,

116 can be found on the IEC website.

117 The committee has decided that the contents of this document will remain unchanged until the

118 stability date indicated on the IEC website under "webstore.iec.ch" in the data related to the

119 specific document. At this date, the document will be
120  reconfirmed,
121  withdrawn,
122  replaced by a revised edition, or
123  amended.
124

125 The National Committees are requested to note that for this document the stability date

126 is 2028.

127 THIS TEXT IS INCLUDED FOR THE INFORMATION OF THE NATIONAL COMMITTEES AND WILL BE DELETED

128 AT THE PUBLICATION STAGE.
129
130
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131 INTRODUCTION

132 The surface insulation coatings on electrical steel strip and sheet are sometimes exposed to

133 elevated temperatures in service or during processing by the purchaser. Therefore, the thermal

134 endurance of the surface insulation coating is important.

135 Physicochemical models postulated for the aging processes lead to the almost universal

136 assumption of the Arrhenius equations to describe the rate of aging (see Annex A and IEC

137 60216-1:2013).

138 Since the measurement of the properties of surface insulation coatings at elevated

139 temperatures is expensive and time-consuming, the thermal endurance of a coating is usually

140 assessed by evaluating a specified coating property before and after a heat treatment.

141
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142 MAGNETIC MATERIALS –
143
144 Part 12: Methods of test for the assessment of the thermal endurance of
145 surface insulation coatings on electrical steel strip and sheet
146
147
148
149 1 Scope

150 This part of IEC 60404 is applicable to surface insulation coatings on electrical steel strip and

151 sheet classified in IEC 60404-1-1.

152 The purpose of this document is to define the general principles and technical details of the

153 tests for the assessment of the thermal endurance of surface insulation coatings on electrical

154 steel strip and sheet.

155 The assessment is made by evaluating the change of a specified property of the surface

156 insulation coating due to a heat treatment at a specified temperature up to 850 °C and a

157 specified duration time up to 2 500 h. The specified property is measured at an ambient

158 temperature of (23 ± 5) °C both without heat treatment and after heat treatment.

159 This document is applicable to the following properties of surface insulation coatings:

160 – adhesion;
161 – surface insulation resistance;
162 – stacking factor.

163 This document is not applicable to other properties of surface insulation coatings, e.g. welding

164 properties, or to other effects e.g. discoloration and off-gassing, which can be caused by

165 exposure to elevated temperatures.

166 NOTE Some of the tests take a very long time to perform and therefore they may not be suitable for acceptance tests of material

167 supplied on a specific order.
168
169 2 Normative references

170 The following documents are referred to in the text in such a way that some or all of their content

171 constitutes requirements of this document. For dated references, only the edition cited applies.

172 For undated references, the latest edition of the referenced document (including any

173 amendments) applies.

174 IEC 60050-121, International Electrotechnical Vocabulary – Part 121: Electromagnetism

175 IEC 60050-131, International Electrotechnical Vocabulary – Part 131: Circuit theory

176 IEC 60050-221, International Electrotechnical Vocabulary – Chapter 221: Magnetic materials

177 and components

178 IEC 60404-1-1, Magnetic materials – Part 1-1: Classification – Surface insulations of electrical

179 steel sheet, strip and lami
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