IEC 60404-8-7:2020
(Main)Magnetic materials - Part 8-7: Specifications for individual materials - Cold-rolled grain-oriented electrical steel strip and sheet delivered in the fully-processed state
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 60404-8-7:2020 is available as IEC 60404-8-7:2020 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 60404-8-7:2020 defines the grades of cold-rolled grain-oriented electrical steel strip and sheet in nominal thicknesses of 0,20 mm, 0,23 mm, 0,27 mm, 0,30 mm and 0,35 mm. In particular, it gives general requirements, magnetic properties, geometric characteristics, tolerances and technological characteristics, as well as inspection procedures. This document applies to Goss textured grain-oriented electrical steel strip and sheet supplied in the final annealed condition in coils or sheets, and intended for the construction of magnetic circuits. The grades are grouped into three classes:
- conventional grades;
- high permeability grades;
- magnetic domain refined high permeability grades.
They correspond to Class C22 of IEC 60404-1.
This edition includes the following significant technical changes with respect to the previous edition:
- insertion of a third class of grain-oriented electrical steels for magnetic domain refined high permeability grades;
- introduction of the single sheet tester (SST) method as reference measurement method for this third class of material together with a conversion factor for transposition of the SST measurement results to equivalent Epstein values;
- update of the electrical steel range to take account of the current offers and demands of grades.
General Information
Standards Content (sample)
IEC 60404-8-7
Edition 5.0 2020-09
INTERNATIONAL
STANDARD
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 60404-8-7:2020-09 (en)
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IEC 60404-8-7
Edition 5.0 2020-09
INTERNATIONAL
STANDARD
Magnetic materials –
Part 8-7: Specifications for individual materials – Cold-rolled grain-oriented
electrical steel strip and sheet delivered in the fully-processed state
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.030 ISBN 978-2-8322-8779-8
Warning! Make sure that you obtained this publication from an authorized distributor.
® Registered trademark of the International Electrotechnical Commission---------------------- Page: 3 ----------------------
– 2 – IEC 60404-8-7:2020 IEC 2020
CONTENTS
FOREWORD ........................................................................................................................... 4
INTRODUCTION ..................................................................................................................... 6
1 Scope .............................................................................................................................. 7
2 Normative references ...................................................................................................... 7
3 Terms and definitions ...................................................................................................... 8
4 Classification ................................................................................................................... 8
5 Designation ..................................................................................................................... 9
6 General requirements ...................................................................................................... 9
6.1 Production process ................................................................................................. 9
6.2 Form of supply ........................................................................................................ 9
6.3 Delivery condition ................................................................................................... 9
6.4 Surface condition .................................................................................................. 10
6.5 Suitability for cutting ............................................................................................. 10
7 Technical requirements ................................................................................................. 10
7.1 Magnetic properties .............................................................................................. 10
7.1.1 General ......................................................................................................... 10
7.1.2 Magnetic polarization ..................................................................................... 10
7.1.3 Specific total loss .......................................................................................... 10
7.1.4 Magnetic properties of magnetic domain refined high permeabilitygrades ........................................................................................................... 10
7.2 Geometric characteristics and tolerances .............................................................. 13
7.2.1 Thickness ...................................................................................................... 13
7.2.2 Width ............................................................................................................. 14
7.2.3 Length ........................................................................................................... 14
7.2.4 Edge wave (wave factor) ............................................................................... 14
7.2.5 Residual curvature ......................................................................................... 15
7.2.6 Edge camber ................................................................................................. 15
7.2.7 Burr height ..................................................................................................... 15
7.3 Technological characteristics ................................................................................ 15
7.3.1 Density .......................................................................................................... 15
7.3.2 Stacking factor............................................................................................... 15
7.3.3 Number of bends ........................................................................................... 15
7.3.4 Deviation from the shearing line (internal stress) ........................................... 15
7.3.5 Insulation coating resistance ......................................................................... 15
8 Inspection and testing .................................................................................................... 16
8.1 General ................................................................................................................. 16
8.2 Selection of samples ............................................................................................. 16
8.3 Preparation of test specimens ............................................................................... 16
8.3.1 Magnetic properties ....................................................................................... 16
8.3.2 Geometrical characteristics and tolerances .................................................... 17
8.3.3 Technological characteristics ......................................................................... 17
8.4 Test methods ........................................................................................................ 18
8.4.1 General ......................................................................................................... 18
8.4.2 Magnetic properties ....................................................................................... 18
8.4.3 Geometrical characteristics and tolerances .................................................... 18
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8.4.4 Technological characteristics ......................................................................... 18
8.5 Retests ................................................................................................................. 19
9 Marking, labelling and packaging ................................................................................... 19
10 Complaints .................................................................................................................... 19
11 Information to be supplied by the purchaser .................................................................. 19
Bibliography .......................................................................................................................... 21
Table 1 – Technological and magnetic properties of the conventional grades of grain-
oriented electrical steel strip and sheet (magnetic properties are measured using the
Epstein method according to IEC 60404-2) ........................................................................... 11
Table 2 – Technological and magnetic properties of the high permeability grades of
grain-oriented electrical steel strip and sheet (magnetic properties are measured using
the Epstein method according to IEC 60404-2) ..................................................................... 12
Table 3 – Technological and magnetic properties of magnetic domain refined highpermeability grades of grain-oriented electrical steel strip and sheet (magnetic
properties are measured using the Single Sheet Test method* accordingto IEC 60404-3). ................................................................................................................... 13
Table 4 – Tolerances on nominal thickness ........................................................................... 14
Table 5 – Tolerances on nominal width ................................................................................. 14
---------------------- Page: 5 ----------------------– 4 – IEC 60404-8-7:2020 IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MAGNETIC MATERIALS –
Part 8-7: Specifications for individual materials –
Cold-rolled grain-oriented electrical steel strip and sheet
delivered in the fully-processed state
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
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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 60404-8-7 has been prepared by IEC technical committee 68:
Magnetic alloys and steels.This fifth edition cancels and replaces the fourth edition published in 2017. This edition
constitutes a technical revision.This edition includes the following significant technical changes with respect to the previous
edition:– insertion of a third class of grain-oriented electrical steels for magnetic domain refined high
permeability grades;– introduction of the single sheet tester (SST) method as reference measurement method for
this third class of material together with a conversion factor for transposition of the SST
measurement results to equivalent Epstein values;– update of the electrical steel range to take account of the current offers and demands of
grades.---------------------- Page: 6 ----------------------
IEC 60404-8-7:2020 IEC 2020 – 5 –
The text of this International Standard is based on the following documents:
CDV Report on voting
68/641/CDV 68/657/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 the 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 "http://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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– 6 – IEC 60404-8-7:2020 IEC 2020
INTRODUCTION
This revision of International Standard IEC 60404-8-7 has been prepared by the experts of the
Working Group 1 of the IEC technical committee 68: Magnetic alloys and steels.The insertion of a third class of electrical steels for magnetic domain refined high permeability
grades is the main reason of this revision. Most of the technologies of magnetic domain
refinement result in material that does not withstand the stress relief annealing after cutting
without changing the magnetic properties (i.e. the specific total loss). In the case of this
material, the Epstein method according to IEC 60404-2, requiring the annealing of the Epstein
test specimens, is not suitable. Therefore, the single sheet tester (SST) method specified in
IEC 60404-3 is employed for such non-heatproof magnetic material.The introduction of the SST as the reference measurement method for these magnetic domain
refined high permeability grades was preceded by intense discussions within IEC/TC 68.
The specific total loss measured by use of the SST specified in IEC 60404-3 tends to be larger
than the value measured by the use of the Epstein frame in accordance with IEC 60404-2. The
magnetic polarization at H = 800 A/m measured by use of the SST tends to be a little lower than
the value measured by the use of the Epstein frame.The significant difference between Epstein and SST loss results made it necessary to introduce
a conversion factor, F , applied to the SST results. This conversion factor is to create continuity
in the quality characteristics ratio of conventional grain-oriented electrical steel grades and of
high permeability grades (Epstein related loss values) to the magnetic domain refined high
permeability grades (SST related loss values), particularly over the transition zone between
these grades. Otherwise, it could be confusing to the users of this document that the higher
quality materials assessed by the SST method would be listed with seemingly higher values of
the specific total loss, compared with the lower values obtained by the Epstein method on the
lower quality materials.Considerations of the widely spread grades of domain refined high permeability grain-oriented
electrical steel led to the consented value of F = 0,925 to be applied to the specific total loss
values at 1,7 T measured by the SST method.The magnetic polarization of magnetic domain refined high permeability grades at H = 800 A/m
is the value taken from the SST measurement without conversion to an equivalent Epstein
value.Consequently, the magnetic domain refined high permeability grades will be listed in a new
Table 3 as a new class of grain-oriented electrical steel strip and sheet.---------------------- Page: 8 ----------------------
IEC 60404-8-7:2020 IEC 2020 – 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
1 Scope
This part of IEC 60404 defines the grades of cold-rolled grain-oriented electrical steel strip and
sheet in nominal thicknesses of 0,20 mm, 0,23 mm, 0,27 mm, 0,30 mm and 0,35 mm. In
particular, it gives general requirements, magnetic properties, geometric characteristics,
tolerances and technological characteristics, as well as inspection procedures.This document applies to Goss textured grain-oriented electrical steel strip and sheet supplied
in the final annealed condition in coils or sheets, and intended for the construction of magnetic
circuits.The grades are grouped into three classes:
– conventional grades;
– high permeability grades;
– magnetic domain refined high permeability grades.
They correspond to Class C22 of IEC 60404-1.
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 60050-221, International Electrotechnical Vocabulary – Chapter 221: Magnetic materials
and componentsIEC 60404-1, Magnetic materials – Part 1: Classification
IEC 60404-1-1, Magnetic materials – Part 1-1: Classification – Surface insulations of electrical
steel sheet, strip and laminationsIEC 60404-2, Magnetic materials – Part 2: Methods of measurement of the magnetic properties
of electrical steel strip and sheet by means of an Epstein frameIEC 60404-3, Magnetic materials – Part 3: Methods of measurement of the magnetic properties
of electrical steel strip and sheet by means of a single sheet testerIEC 60404-9, Magnetic materials – Part 9: Methods of determination of the geometrical
characteristics of electrical steel strip and sheetIEC 60404-11, Magnetic materials – Part 11: Method of test for the determination of surface
insulation resistance of magnetic sheet and stripIEC 60404-13, Magnetic materials – Part 13: Methods of measurement of resistivity, density,
and stacking factor of electrical steel strip and sheetISO 404, Steel and steel products – General technical delivery requirements
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– 8 – IEC 60404-8-7:2020 IEC 2020
ISO 7799, Metallic materials – Sheet and strip 3 mm thick or less – Reverse bend test
ISO 10474, Steel and steel products – Inspection documents3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-121,
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
edge wave
wave factor
variations of flatness of a length of strip or a sheet taking a form of waves at the slit edge of the
productNote 1 to entry: The edge wave is characterized by the wave factor which is the relation of the height of the wave
to its length, expressed as a percentage.[SOURCE: IEC 60404-9:2018, 3.1]
3.2
residual curvature
variations of flatness of a length of strip or a sheet taking a permanent curvature in the rolling
direction of the product[SOURCE: IEC 60404-9:2018, 3.2]
3.3
edge camber
greatest distance between a longitudinal edge of a length of strip or a sheet and the line joining
the two extremities of the measured length of this edge[SOURCE: IEC 60404-9:2018, 3.3]
3.4
deviation from the shearing line
internal stress
greatest distance between corresponding points on the two sheared edges of a length of strip
or a sheet sheared in the middle of the width, in parallel to the rolling direction of the product,
which characterizes the internal stress of the materials[SOURCE: IEC 60404-9:2018, 3.4]
3.5
number of bends
counts of alternate bending in the reverse bend test prior to the appearance of the first crack in
the base metal of the specimen visible to the naked eye or prior to when sudden failure occurs
by fracture[SOURCE: IEC TR 63114:2018, 3.2]
4 Classification
The grades covered by this document are classified according to the specified value of
maximum specific total loss at a magnetic polarization of 1,7 T and 50 Hz, in watts per kilogram,
---------------------- Page: 10 ----------------------IEC 60404-8-7:2020 IEC 2020 – 9 –
and according to the nominal thickness of the product (0,20 mm, 0,23 mm, 0,27 mm, 0,30 mm
and 0,35 mm).5 Designation
The steel name comprises the following in the order given:
1) a letter “M” for electrical steel;
2) one hundred times the specified value of maximum specific total loss at 1,7 T and 50 Hz, in
watts per kilogram;3) one hundred times the nominal thickness of the product, in millimeters;
4) the characteristic letter
– “S” for conventional grades;
– “P” for high permeability grades;
– “R” for magnetic domain refined high permeability grades;
5) one tenth of the frequency 50 Hz, i.e. 5.
EXAMPLE M120-30S5 for cold-rolled grain-oriented electrical steel strip or sheet of conventional grade with a
maximum specific total loss of 1,20 W/kg at 1,7 T and 50 Hz, and a nominal thickness of 0,30 mm, supplied in the
fully-processed state.6 General requirements
6.1 Production process
The production process of the steel and its chemical composition are left to the discretion of
the manufacturer.6.2 Form of supply
The product is supplied in coils in the case of strip or in bundles in the case of sheets.
The mass of the coils or bundles of sheets shall be agreed between the manufacturer and the
purchaser at the time of enquiry and order.The recommended value for the internal diameter of coils is approximately 508 mm.
Strip 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 in order that they do not collapse under their own weight.
Strip may exhibit welds or interleaves resulting from the removal of defective zones if agreed
between the manufacturer and the purchaser at the time of enquiry and order. If necessary, the
marking of welds or interleaves may be agreed between the manufacturer and the purchaser at
the time of enquiry and order.For coils containing repair welds or interleaves, each part of the strip shall be of the same
grade.The edges of parts welded together shall not be so much out of alignment as to affect the further
processing of the product.Sheets which make up each bundle shall be stacked so that the side faces are substantially flat
and approximately perpendicular to the top face.6.3 Delivery condition
Cold-rolled grain-oriented electrical steel products are usually supplied with an insulating
coating on both sides. This coating generally consists of an EC-5-G coating on an EC-2 coating
___________In the rest of the document, the word "product" is used to mean "strip and sheet".
---------------------- Page: 11 ----------------------– 10 – IEC 60404-8-7:2020 IEC 2020
in accordance with IEC 60404-1-1. Other types of coating exist which are used only when
particularly specified.6.4 Surface condition
The surfaces shall be smooth and clean, free from grease and rust . Dispersed defects such
as scratches, blisters, cracks, etc. are only permitted if they are within the limits of the
tolerances on thickness and if they are not detrimental to the correct use of the supplied product.
The insulation coating present on the surface of the product shall be sufficiently adherent so
that it does not become detached during core manufacturing operations or heat treatment under
conditions specified by the manufacturer.If the product is to be immersed in a fluid, an agreement between the manufacturer and the
purchaser, initiated by the purchaser, should be reached to ensure compatibility between the
fluid and the coating.6.5 Suitability for cutting
The product shall be suitable for cutting accurately into the usual shapes at any point when
appropriate cutting tools are used.7 Technical requirements
7.1 Magnetic properties
7.1.1 General
The properties defined in 7.1.2 and 7.1.3 shall apply to products in the delivery condition defined
in 6.3 and to the aged condition defined in 8.3.1.1 and 8.3.1.2.The Epstein strips shall receive a stress relief heat treatment after cutting under conditions
specified by the manufacturer.The test specimen for the single sheet tester (SST) method shall not be heat treated.
7.1.2 Magnetic polarizationThe specified minimum values of peak magnetic polarization at the peak magnetic field strength
of 800 A/m at 50 Hz or 60 Hz shall be as given in Tables 1 to 3.7.1.3 Specific total loss
The specified values of maximum specific total loss at 50 Hz or 60 Hz shall be as given in Table
1, Table 2 and Table 3.7.1.4 Magnetic properties of magnetic domain refined high permeability grades
The magnetic properties are measured in accordance with the single sheet tester method
specified in IEC 60404-3.In Table 3, the specific total loss at 1,7 T and 50 Hz or 60 Hz is treated on the basis of an
equivalent Epstein value obtained by multiplying the SST measurement result at 1,7 T and
50 Hz or at 60 Hz by a conversion factor, F , equal to 0,925.The conversion factor, F , for non-specific values, e.g. at 1,5 T, may be subject to agreement
between the manufacturer and the purchaser at the time of enquiry and order.In Table 3, the magnetic polarization at H = 800 A/m is measured in accordance with the SST
method without conversion to an equivalent Epstein value.___________
Not to be confused with some coloration of the insulating coating inherent to the manufacturing process.
The specific total loss measured by an SST specified in IEC 60404-3 tends to be higher than the value measured
by an Epstein frame specified in IEC 60404-2. The magnetic polarization at H = 800 A/m measured by an SST
tends to be a little lower than the value measured by an Epstein frame.---------------------- Page: 12 ----------------------
IEC 60404-8-7:2020 IEC 2020 – 11 –
There are technologies of heatproof magnetic domain refinement which res
...
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