EN 10251:2024

SLOVENSKI STANDARD
01-maj-2024
Magnetni materiali - Metode za ugotavljanje geometrijskih lastnosti
elektropločevin in trakov
Magnetic materials - Methods of determination of the geometrical characteristics of
electrical steel sheet and strip
Magnetische Werkstoffe - Verfahren zur Bestimmung der geometrischen Kenngrößen
von Elektroblech und -band
Matériaux magnétiques - Méthodes de détermination des caractéristiques géométrique
des bandes et tôles en acier électrique
Ta slovenski standard je istoveten z: EN 10251:2024
ICS:
29.030 Magnetni materiali Magnetic materials
77.140.50 Ploščati jekleni izdelki in Flat steel products and semi-
polizdelki products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 10251
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2024
EUROPÄISCHE NORM
ICS 29.030; 77.140.50 Supersedes EN 10251:2015
English Version
Magnetic materials - Methods of determination of the
geometrical characteristics of electrical steel sheet and
strip
Matériaux magnétiques - Méthodes de détermination Magnetische Werkstoffe - Verfahren zur Bestimmung
des caractéristiques géométrique des bandes et tôles der geometrischen Kenngrößen von Elektroblech und -
en acier électrique band
This European Standard was approved by CEN on 8 January 2024.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 10251:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Test Methods . 5
4.1 Edge wave . 5
4.2 Residual curvature . 6
4.3 Edge camber. 8
4.4 Deviation from the shearing line due to internal stresses . 9
4.5 Burr height . 10
5 Test report . 12
Annex A (informative) Examples of clamping systems . 13
Bibliography . 15

European foreword
This document (EN 10251:2024) has been prepared by Technical Committee CEN/TC 459/SC 8 “Steel
sheet and strip for electrical applications”, the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by September 2024, and conflicting national standards shall
be withdrawn at the latest by September 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 10251:2015.
The main changes compared to the previous edition are as follows:
— the definitions have been updated, in particular replacement of “flatness” with “edge wave”;
— the test methods have been amended as follows:
— edge wave: the requirements for the test specimen and the measuring procedure have been
updated;
— residual curvature: the horizontal method has been added (the residual curvature can be made
with both a vertical and a horizontal method);
— edge camber: the requirements for the test specimen and the measuring procedure have been
updated;
— deviation from the shearing line due to internal stresses: the requirements for the test specimen
and the measuring procedure have been updated;
— burr height: the requirements for the test specimen and the measuring procedure have been
updated, and the measuring procedure using a hand-held micrometre for the thickness has been
added;
— the test report has been updated.
The author thanks the International Electrotechnical Commission (IEC) for permission to reproduce
Information from its International Standards. All such extracts are copyright of IEC, Geneva, Switzerland.
All rights reserved. Further information on the IEC is available from www.iec.ch. IEC has no responsibility
for the placement and context in which the extracts and contents are reproduced by the author, nor is
IEC in any way responsible for the other content or accuracy therein.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
1 Scope
This document is intended to define the test methods used for the determination of the following
geometrical characteristics of electrical steel sheet and strip:
— edge wave;
— residual curvature;
— edge camber;
— deviation from the shearing line due to internal stresses;
— burr height of cut edges.
This document applies to electrical steel sheet and strip intended for the construction of magnetic circuits
and corresponding to Clauses B2, C21, C22 and C23 of EN 60404-1:2017.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
edge wave
wave factor
variation of flatness of a length of strip or sheet taking a form of waves at the slit edge of the product after
longitudinal side trimming or slitting; characterised by the wave factor, i.e. by the relation of the height
of the wave to its length
Note 1 to entry: For examples of waves, see Figure 1.
3.2
residual curvature
variations of flatness of a length of unwound strip or a sheet taking a permanent curvature in the direction
of rolling of the product
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
Note 1 to entry: See Figure 5.
[SOURCE: IEC 60404-9:2018, definition 3.3]
3.4
deviation from the shearing line
greatest distance between corresponding points on the two cut 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 may
characterise the internal stress of the materials
Note 1 to entry: See Figure 6.
3.5
burr height
difference between the thicknesses of a length of strip or a sheet measured respectively at the cut edge
of the sheet and at a distance of 10 mm from this edge
Note 1 to entry: See Figure 7.
4 Test Methods
4.1 Edge wave
4.1.1 Test specimen
The test specimen shall consist of a sheet or a length of strip, the size of which is defined in the product
standard. If it is not defined in the product standard, the length shall be 1 m. Its width shall be equal to
the delivered width of the product. The axis of the specimen shall be parallel to the rolling direction.
4.1.2 Measuring procedure
The test specimen shall be placed on a flat surface (e.g. a granite, marble, table) which is sufficiently large
so that the test specimen does not overhang the edges (see Figure 1). It shall then be lifted up on one edge
and allowed to fall back. The height of the maximum wave (h) shall be measured by means of an
instrument having a resolution of 0,1 mm or better. The length of the wave (l) shall be measured by means
of an instrument having a resolution of 1 mm or better (see Figure 2). Only complete waves are taken
into account.
The wave factor shall be determined as the ratio of the height of the wave (h) to its length (l), expressed
as a percentage (see Figure 2).
Key
1 flat surface
2 sheet
3 rolling direction
h height of wave (mm)
l length of wave (mm)
Figure 1 — Example of wave
Figure 2 — Wave factor
4.2 Residual curvature
4.2.1 General
Two methods for the determination of the residual curvature in the rolling direction of the product are
described in this document: a horizontal method and a vertical method.
NOTE 1 The vertical method is adopted in EN 10106:2015, EN 10107:2022 and EN 10303:2015. The horizontal
method is an option that can be relevant for thin products. The horizontal method is also used for sheets in
EN 10265.
For the horizontal method, the maximum distance (d) between the test specimen and a flat surface, on
which the test specimen is placed, shall be measured. For the vertical method, the maximum distance (a)
between the bottom edge of the test specimen and a supporting plate shall be measured.
NOTE 2 Both the horizontal and vertical methods are applicable to test specimens obtained from electrical steel
strips and sheets of any grade. These two methods give different values.
4.2.2 Horizontal method
4.2.2.1 Test specimen
The test specimen shall consist of a length of strip or a sheet, the length of which is defined in the product
standard. If it is not defined in the product standard, the length shall be 1 m. Its width shall be equal to
the delivered width of the product. The test specimen for the determination of edge wave (wave factor)
may be used.
4.2.2.2 Measuring procedure
The test shall consist of placing the test specimen lying under its weight on a flat surface sufficiently large
so that the test specimen does not overhang the edges (see Figure 1). The convex surface of the test
specimen shall be in contact with the surface plate. The maximum distance (d) between the lower surface
of the test specimen and the surface plate shall be measured by means of an instrument having a
resolution of 1 mm or better (see Figure 3).

1)
Figure 3 — Verification of the residual curvature (horizontal method)
4.2.3 Vertical method
4.2.3.1 Test specimen
The test specimen shall consist of a length of strip or a sheet, the length of which is defined in the product
standard. If it is not defined in the product standard, the length shall be 500 mm. Its width shall be equal
to the delivered width of the product. The axis of the test specimen shall be parallel to the direction of
rolling of the product.
4.2.3.2 Measuring procedure
The test shall consist of placing the test specimen vertically against a supporting plate. The top of the test
specimen shall be held against the supporting plate over a clamping length of 30 mm with its convex
surface facing the supporting plate. The maximum distance (a) between the bottom edge of the test
specimen and the supporting plate shall then be measured at the axis of the test specimen by means of a
graduated rule having a resolution of 1 mm or better (see Figure 4). The clamping force shall be sufficient
to allow the full width of the test specimen to be in contact with the support (see in Figures A.1 and A.2
examples of clamping systems).

1)
IEC 60404-9 ed.2.0 “Copyright © 2018 IEC Geneva, Switzerland. www.iec.ch”
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