oSIST prEN 10303:2026
(Main)Magnetics materials - Thin magnetic steel strip and sheet for use at medium frequencies
- Abstract
This document defines the grades of thin non-oriented magnetic steel strip and sheet in nominal thicknesses of 0,10 mm, 0,15 mm, 0,20 mm, 0,25 mm, 0,27 mm, 0,30 mm and 0,35 mm, and of thin grain-oriented magnetic steel strip and sheet in nominal thicknesses of 0,10 mm, 0,15 mm and 0,18 mm. In particular, it gives general requirements, magnetic properties, geometric characteristics and tolerances and technological characteristics, as well as inspection procedure.
This document applies to magnetic steel strip and sheet supplied in the finally annealed condition in coils and intended for the construction of magnetic circuits used at frequencies equal to or higher than 100 Hz.
- Status
- Not Published
- Public Enquiry End Date
- 04-Sep-2026
- Technical Committee
- IFEK - Ferrous metals
- Current Stage
- 4020 - Public enquire (PE) (Adopted Project)
- Start Date
- 14-Jul-2026
- Due Date
- 01-Dec-2026
- Completion Date
- 07-Sep-2026
oSIST prEN 10303:2026 is the Slovenian adoption of the draft European Standard prEN 10303 for thin magnetic steel strip and sheet for use at medium frequencies. It specifies grades, magnetic properties, geometric tolerances, technological characteristics and inspection rules for non-oriented and grain-oriented products supplied in coils after final annealing, for magnetic circuits used at frequencies of 100 Hz and above.
What does oSIST prEN 10303:2026 specify?
oSIST prEN 10303:2026 sets the product grades, how they are designated, what the purchaser has to state in an order, and the requirements the delivered material has to meet. It covers the full path from supply condition and surface quality through magnetic, geometric and technological properties to inspection, marking and complaints.
The standard applies to thin magnetic steel strip and sheet in coils, in the nominal thicknesses stated in the scope for non-oriented and grain-oriented grades. Clause 4 classifies the grades by maximum specific total loss and thickness, clause 5 defines ordering information, clauses 6 to 8 cover delivery and testing, and clauses 9 and 10 cover marking and complaints.
| Annex | What it covers |
|---|---|
| Annex A | Minimum stacking factor for non-oriented coated products |
| Annex B | Guidance values for maximum specific total loss of non-oriented products at 1.0 T and 700 Hz, and at 1.5 T and 400 Hz |
| Annex C | Density determination by formula |
| Annex D | Mechanical properties for non-oriented products |
What are the key requirements of oSIST prEN 10303:2026?
Product definition and ordering
The standard separates non-oriented and grain-oriented products and gives conventional designations such as NO and GO with the nominal thickness and, where relevant, the loss grade. In practice, this is what buyers use to specify the material they need and what manufacturers use to identify the delivered grade.
Clause 5 requires the purchaser to state key order data such as product type, grade designation, coil direction, coil dimensions, mass limits, insulation coating, and the inspection procedure. This matters because several features are only supplied by agreement, so the order has to record them clearly.
Clause 6 states that the steel is supplied in coils, generally in the finally annealed condition. The coil form, winding, internal diameter, welds or interleaves, and package masses are subject to agreement, which matters for handling, slitting and downstream processing.
Magnetic and mechanical performance
Clause 7 gives the magnetic property requirements and the test methods used to verify them. Magnetic properties are measured with EN 60404-2 for power frequencies or IEC 60404-10 for medium frequencies, so the reader knows which method applies to the intended use.
For grain-oriented material, the standard specifies minimum magnetic polarization at a peak field strength of 800 A/m and the relevant frequency, together with maximum specific total loss. For non-oriented material, the requirements are given at 2 500 A/m, 5 000 A/m and 10 000 A/m, again with loss limits tied to thickness and frequency. In practice, this is the core performance data that determines whether the material is fit for an electrical machine or magnetic circuit design.
The document also deals with the effect of insulation coating on measured properties. For coated products, coating mass and stacking factor have to be considered, and the coating properties can be assessed by the methods cited in Clause 7.4.3.4. That matters because coatings influence both magnetic performance and how much steel ends up in a stack.
Clause 7.2 gives mechanical properties for non-oriented products by agreement, with values placed in Annex D. This is useful when the material will be punched, formed or otherwise mechanically stressed during manufacture.
Geometry, tolerances and workmanship
Clause 7.3 sets thickness tolerances, width tolerances and shape tolerances. The standard distinguishes between grain-oriented and non-oriented products, and in some cases between slit edges and as-rolled edges. For users, this determines whether the strip will fit tooling, laminations and assembly processes.
The document also controls edge camber, edge wave, residual curvature and burr height for the relevant product categories. These limits matter in practice because poor flatness or excessive burrs can cause fitting problems, punching defects, assembly difficulty and higher tool wear.
Clause 6.4 requires the surface to be smooth, clean and free from grease and rust, with only limited dispersed imperfections allowed if they do not harm use and remain within thickness tolerance. Where insulation coating is supplied, the coating has to remain adherent during forming and testing. Clause 6.5 adds that the product has to be suitable for cutting or punching with normal tooling.
Inspection, acceptance and retests
Clause 8 links each specified property to sampling and test methods. It defines acceptance units, sample selection, specimen preparation and retest rules, so buyers and laboratories can apply the same evaluation basis.
For magnetic testing, the standard uses a 25 cm Epstein frame and defines the number and orientation of Epstein strips, including higher strip counts if agreed. For geometric checks and technological tests, it sets specimen length, test orientation and the relevant measurement standards. If a result is unsatisfactory, the clause allows retesting on doubled specimens from other parts of the acceptance unit.
Clause 8.1 also states how inspection documents are handled under EN 10204, including the case where no specific inspection is ordered. This is important for purchasing and quality control because it defines what documents accompany delivery.
What terms does oSIST prEN 10303:2026 define?
Non-oriented (NO) means strip or sheet intended to have magnetic properties that are not direction-dependent in use. It is the product family used where magnetic flux rotates or varies in multiple directions.
Grain-oriented (GO) means strip or sheet whose magnetic properties are optimized along the rolling direction. It is used where the magnetic circuit follows a preferred direction.
Acceptance unit is the coil or grouped coil unit on which inspection results are based. This matters because test results apply to the unit as delivered or reworked.
Edge camber is the sideways deviation of a longitudinal edge from a straight line between the ends of the measured length. It is a practical flatness check.
Edge wave or wave factor is the waviness at the slit edge, expressed by the relation between wave height and wave length. It helps control strip quality after slitting or trimming.
Residual curvature is the permanent curvature along the rolling direction in unwound strip or sheet. It affects flatness and handling in downstream processing.
Number of bends is the number of alternating bends possible before the first visible crack appears in the base metal. It is used as a simple ductility indicator.
Who uses oSIST prEN 10303:2026?
Manufacturers of electrical steel strip and sheet use this standard to produce and certify grades with defined magnetic and geometric properties. Purchasers and buyers use it to specify material, coating, coil dimensions and inspection requirements in orders.
Quality managers and inspection laboratories use it for sampling, test preparation, magnetic measurement, tensile testing and dimensional verification. It is also used by manufacturers of electrical machines, magnetic circuits and laminated cores who need material suited to punching, stacking and low-loss magnetic performance.
What changed in oSIST prEN 10303:2026 from the previous edition?
oSIST prEN 10303:2026 states that it supersedes EN 10303:2015. The foreword lists these significant technical changes:
- normative references and definitions have been updated
- the list of options is more detailed
- the term “defects” has been replaced by “imperfections”
- technical changes were made throughout to improve the tolerances supplied
- the 0.05 mm thickness has been removed for both grain-oriented and non-oriented grades
- editorial changes were made to improve the text
Which standards are used with oSIST prEN 10303:2026?
- EN 10021 - general technical delivery conditions for steel products, and the basis for complaints handling
- EN 10204 - inspection documents for metallic products
- EN 10251:2024 - geometric characteristics of electrical steel sheet and strip, including edge camber, edge wave, residual curvature and burr height
- EN 10342 - classification of surface insulations of electrical steel sheet, strip and laminations
- EN 60404-2 - Epstein frame method for magnetic properties at power frequencies
- EN IEC 60404-11 - measurement of surface insulation resistance
- EN IEC 60404-12 - thermal endurance testing of surface insulation coatings
- EN IEC 60404-13 - measurement of resistivity, density and stacking factor
- EN ISO 377 - sampling and preparation of mechanical test pieces
- EN ISO 6892-1 - tensile testing at room temperature
- EN ISO 7799 - reverse bend test
- IEC 60050-121 and IEC 60050-221 - terminology for electromagnetism and magnetic materials
- IEC 60404-10 - magnetic properties at medium frequencies
- CEN/TR 17856 and CEN/TR 18048 - supporting guidance for coating properties and self-bonding coatings
What does the oSIST prEN 10303:2026 document contain?
The document contains classification and designation rules, purchaser information requirements, general delivery conditions, technical property tables, inspection rules and complaint handling. It includes tables for magnetic performance, thickness and width tolerances, stacking factor, bend values and tensile properties, plus annexes that extend the main text with coated-product stacking factors, additional loss values, a density formula and mechanical properties for non-oriented grades.
It also includes figures that illustrate edge wave and edge camber, and test procedures for Epstein-frame magnetic measurements, tensile testing, reverse bend testing, geometric measurements and retests. For users, this means the standard is not just a list of limits - it also tells them how to prepare samples, how to measure them and how to interpret the results.
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- Effective Date
- 19-Nov-2025
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Frequently Asked Questions
oSIST prEN 10303:2026 is a draft published by the Slovenian Institute for Standardization (SIST). Its full title is "Magnetics materials - Thin magnetic steel strip and sheet for use at medium frequencies". This standard covers: This document defines the grades of thin non-oriented magnetic steel strip and sheet in nominal thicknesses of 0,10 mm, 0,15 mm, 0,20 mm, 0,25 mm, 0,27 mm, 0,30 mm and 0,35 mm, and of thin grain-oriented magnetic steel strip and sheet in nominal thicknesses of 0,10 mm, 0,15 mm and 0,18 mm. In particular, it gives general requirements, magnetic properties, geometric characteristics and tolerances and technological characteristics, as well as inspection procedure. This document applies to magnetic steel strip and sheet supplied in the finally annealed condition in coils and intended for the construction of magnetic circuits used at frequencies equal to or higher than 100 Hz.
This document defines the grades of thin non-oriented magnetic steel strip and sheet in nominal thicknesses of 0,10 mm, 0,15 mm, 0,20 mm, 0,25 mm, 0,27 mm, 0,30 mm and 0,35 mm, and of thin grain-oriented magnetic steel strip and sheet in nominal thicknesses of 0,10 mm, 0,15 mm and 0,18 mm. In particular, it gives general requirements, magnetic properties, geometric characteristics and tolerances and technological characteristics, as well as inspection procedure. This document applies to magnetic steel strip and sheet supplied in the finally annealed condition in coils and intended for the construction of magnetic circuits used at frequencies equal to or higher than 100 Hz.
oSIST prEN 10303:2026 is classified under the following ICS (International Classification for Standards) categories: 77.140.40 - Steels with special magnetic properties; 77.140.50 - Flat steel products and semi-products. The ICS classification helps identify the subject area and facilitates finding related standards.
oSIST prEN 10303:2026 has the following relationships with other standards: It is inter standard links to SIST EN 10303:2016. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
oSIST prEN 10303:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2026
Magnetni materiali - Tanka magnetna jeklena pločevina in trakovi za uporabo pri
srednjih frekvencah
Magnetics materials - Thin magnetic steel strip and sheet for use at medium frequencies
Magnetische Werkstoffe - Dünnes Elektroband und -blech aus Stahl zur Verwendung bei
mittleren Frequenzen
Matériaux magnétiques - Bandes et tôles magnétiques minces en acier pour utilisation à
moyennes fréquences
Ta slovenski standard je istoveten z: prEN 10303
ICS:
77.140.40 Jekla s posebnimi Steels with special magnetic
magnetnimi lastnostmi properties
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.
DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2026
ICS 77.140.40; 77.140.50 Will supersede EN 10303:2015
English Version
Magnetics materials - Thin magnetic steel strip and sheet
for use at medium frequencies
Matériaux magnétiques - Bandes et tôles magnétiques Magnetische Werkstoffe - Dünnes Elektroband und -
minces en acier pour utilisation à moyennes blech aus Stahl zur Verwendung bei mittleren
fréquences Frequenzen
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 459/SC 8.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 10303:2026 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Classification and designation . 7
4.1 Classification . 7
4.2 Designation . 7
5 Information to be supplied by purchaser . 8
5.1 Mandatory information . 8
5.2 Options . 8
5.3 Example of an order . 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 . 9
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
7.2 Mechanical properties at room temperature for non-oriented products . 12
7.3 Geometric characteristics and tolerances . 13
7.3.1 Thickness of grain-oriented steel products . 13
7.3.2 Thickness of non-oriented steel products . 13
7.3.3 Width . 14
7.3.4 Edge camber . 15
7.3.5 Edge wave (wave factor). 15
7.3.6 Residual curvature . 15
7.3.7 Burr height . 16
7.4 Technological characteristics . 16
7.4.1 Density . 16
7.4.2 Stacking factor . 16
7.4.3 Number of bends . 16
8 Inspection . 16
8.1 General . 16
8.2 Selection of samples . 17
8.3 Preparation of test specimens . 17
8.3.1 Magnetic properties . 17
8.3.2 Mechanical properties . 18
8.3.3 Geometrical characteristics and tolerances . 18
8.3.4 Technological characteristics . 19
8.4 Test methods . 19
8.4.1 General . 19
8.4.2 Magnetic properties . 19
8.4.3 Mechanical properties . 19
8.4.4 Geometrical characteristics and tolerances . 20
8.4.5 Technological characteristics . 20
8.4.6 Retests . 21
9 Marking, labelling and packaging . 21
10 Complaints . 21
Annex A (informative) Minimum stacking factor for non-oriented coated products . 22
Annex B (informative) Maximum specific total loss at 1,0 T and 700 Hz and at 1,5 T and 400 Hz for
non-oriented products . 23
Annex C (informative) Density determination . 24
Annex D (informative) Mechanical properties for non-oriented products . 25
Bibliography . 26
European foreword
This document (prEN 10303:2026) 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 document is currently submitted to the CEN Enquiry.
This document will supersede EN 10303:2015.
— the normative references and the definitions have been updated;
— the list of options is more detailed (see 5.2);
— “defects” has been replaced by “imperfections”;
— throughout the document technical changes have been made to improve the tolerances supplied;
— 0,05 mm thickness have been removed for both grain oriented and non-oriented grades;
— throughout the document, editorial changes have been made to improve the quality of the text.
1 Scope
This document defines the grades of thin non-oriented magnetic steel strip and sheet in nominal
thicknesses of 0,10 mm, 0,15 mm, 0,20 mm, 0,25 mm, 0,27 mm, 0,30 mm and 0,35 mm, and of thin grain-
oriented magnetic steel strip and sheet in nominal thicknesses of 0,10 mm, 0,15 mm and 0,18 mm. In
particular, it gives general requirements, magnetic properties, geometric characteristics and tolerances
and technological characteristics, as well as inspection procedure.
This document applies to magnetic steel strip and sheet supplied in the finally annealed condition in coils
and intended for the construction of magnetic circuits used at frequencies equal to or higher than 100 Hz.
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.
EN 10021, General technical delivery conditions for steel products
EN 10204, Metallic products — Types of inspection documents
EN 10251:2024, Magnetic materials — Methods of determination of the geometrical characteristics of
electrical steel sheet and strip
EN 10342, Magnetic materials — Classification of surface insulations of electrical steel sheet, strip and
laminations
EN 60404-2, Magnetic materials — Part 2: Methods of measurement of the magnetic properties of electrical
steel strip and sheet by means of an Epstein frame (IEC 60404-2)
EN IEC 60404-11, Magnetic materials — Part 11: Methods of measurement of the surface insulation
resistance of electrical steel strip and sheet (IEC 60404-11)
EN IEC 60404-12, 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)
EN IEC 60404-13, Magnetic materials — Part 13: Methods of measurement of resistivity, density and
stacking factor of electrical steel strip and sheet (IEC 60404-13)
EN ISO 377, Steel and steel products — Location and preparation of samples and test pieces for mechanical
testing (ISO 377)
EN ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
(ISO 6892-1)
EN ISO 7799, Metallic materials — Sheet and strip 3 mm thick or less — Reverse bend test (ISO 7799)
IEC 60050-121, International Electrotechnical Vocabulary — Chapter 121: Electromagnetism
IEC 60050-221, International Electrotechnical Vocabulary — Chapter 221: Magnetic materials and
components
IEC 60404-10, Magnetic materials — Part 10: Methods of measurement of magnetic properties of electrical
steel strip and sheet at medium frequencies
3 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 terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
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 of the product; 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.
[SOURCE: EN 10251:2024, definition 3.1]
Key
1 flat surface
2 sheet
3 rolling direction
h height of wave (mm)
l length of wave (mm)
Figure 1 — Example of wave
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
[SOURCE: EN 10251:2024, definition 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
Note 1 to entry: See Figure 2.
[SOURCE: EN 10251:2024, definition 3.3]
Figure 2 — Verification of the edge camber
3.4
number of bends
number of alternate bends possible before the appearance of the first crack in the base metal visible to
the naked eye indicating the ductility of the material
4 Classification and designation
4.1 Classification
The grades covered by this document are classified according to the value of the maximum specific total
loss, in watts per kilogram, and according to the nominal thickness of the material (0,10 mm, 0,15 mm,
0,20 mm, 0,25 mm, 0,27 mm, 0,30 mm and 0,35 mm for non-oriented steel, respectively 0,10 mm,
0,15 mm and 0,18 mm for grain-oriented steel).
4.2 Designation
For the steel grades covered by this document, the conventional designation of the different grades
comprises the following in the order:
a) the characteristic letters:
1) NO for non-oriented strip and sheet;
2) GO for grain-oriented strip and sheet;
b) one hundred times the nominal thickness of the material, in millimetres;
EXAMPLE NO 20: non-oriented strip in thickness of 0,20 mm.
c) number of the specified value of maximum specific total loss by given frequency, in watts per
kilogram and corresponding to the nominal product thickness, in cases where steel grades with
different values for maximum specific total loss per nominal thickness are stated (see Table 2).
5 Information to be supplied by purchaser
5.1 Mandatory information
For material to adequately comply with the requirements of this document, the purchaser shall include
the following information in his enquiry or order:
a) the quantity required (see 6.2);
b) the type of product (strip or sheet);
c) the number of this document, i.e. EN 10303;
d) the grade designation of the material (see 4.2);
e) the direction of coils, axis horizontal (h) or vertical (v) (see 6.2);
f) the internal diameter of coil (see 6.2);
g) any limitation on the mass of a bundle of sheets or of a coil or limitation of external diameter (see
6.2);
h) any limitation of the mass of the packing unit (6.2);
i) the presence and type of insulation coating (see 6.3);
j) the dimensions of strips or sheets required, including any limitations of the internal and external
diameter of a coil-(see 6.2 and 7.3.3);
k) the inspection procedure required including the nature of the related documents (see 8.1).
5.2 Options
The following options may be agreed at the time of enquiry and order. lf the purchaser does not indicate
his wish to implement one of these options, the products shall be supplied in accordance with the basis
specification of this document (see 6.1).
1) smaller value of the internal diameter (see 6.2);
2) permissibility of welds or interleaves and their optional marking (see 6.2);
3) insulation coating properties (see 6.3);
d
4) density determination (see Table 2, Footnote and Annex C);
5) minus or plus tolerances for nominal width (see Table 4 or Table 5);
6) stacking factor values of non-oriented products supplied with insulation coating (see 7.4.2);
7) specific inspection (see 8.1);
8) type of acceptance unit (see 8.1);
9) higher number of strips for Epstein test (see Table 6);
10) marking of the products (see Clause 9);
11) mechanical properties for non-oriented products (see Table D.1).
5.3 Example of an order
18 t strip with 0,30 mm thickness in accordance with EN 10303, made of steel grade NO 27-15, delivered
in coils with a width of 1 000 mm and a maximum mass of 3 500 kg, vertical coil axis (v), with specific
inspection, inspection report 3.1 in accordance with EN 10204:
18 t – strip – EN 10303 — NO 27-15 – 1000 mm – max. 3500 kg – v – 3.1
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 material is supplied in coils.
The mass of coils and/or the external diameter shall be agreed at the time of enquiry and order.
The mass of the package unit shall be agreed at the time of enquiry and order.
The recommended value for the internal diameter of coils is approximately 508 mm or 610 mm. Smaller
internal diameters can be agreed between the manufacturer and the purchaser at the time of enquiry and
order (see 5.2, option 1).
The strip shall be of constant width and wound in such a manner that the edges are superimposed in a
regular manner and that the side faces of the coil are substantially flat.
The coils shall be sufficiently tightly wound so that they do not collapse under their own weight.
The 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 (see 5.2, option 2). If
necessary, the marking of welds or interleaves may be agreed between the manufacturer and the
purchaser at the time of enquiry and order form the subject of a special agreement.
For coils containing repair welds or interleaves, each part of the strip shall be of the same grade material.
The edges of parts welded together shall not be so much out of alignment as to affect further processing
of the product.
6.3 Delivery condition
The products are usually supplied either without insulation or with insulation in accordance with
EN 10342. When the product is supplied with insulation, the nature of the insulation, its thickness and
properties, the stacking factor and their verification shall be agreed at the time of enquiry and order
(see 5.2, Option 3) and in accordance with the values stated in Table A.1.
6.4 Surface condition
1)
The surfaces shall be smooth and clean and free from grease and rust. Dispersed imperfections such as
scratches, blisters, cracks, etc. are only permitted if the products are within the tolerances on thickness
and if these imperfections are not detrimental to the correct use of the supplied material.
1) This should not be confused with some coloration of the insulating coating inherent in the manufacturing
process.
For products supplied with insulation coating, the coating shall be sufficiently adherent so that it does
not to become detached during manufacturing operations. During the reverse bend test (see 8.4.4.2), the
coating shall not become detached after a bend of 90°. If the coating becomes detached during the test,
the piece from which the sample of the product from which the test specimen was taken shall be subjected
to a shearing test. By shearing the sample with well sharpened tools, a detachment of large pieces of the
coating shall not be admissible. However, some slight chipping of the coating at the sheared edges shall
be tolerated.
If the product is to be immersed in a fluid or is to be given an additional coating or impregnation, an
agreement initiated by the purchaser should be reached with the supplier to ensure compatibility
between the fluid and the surface insulation coating.
For non-oriented products, CEN/TR 17856 and CEN/TR 18048 describe all the relevant measurement
procedures for coating properties.
6.5 Suitability for cutting
The product shall be suitable for cutting or punching without causing premature wear of the tools. The
product shall be suitable for cutting or punching accurately into the usual shapes when appropriate
cutting or punching tools and technologies are used.
7 Technical requirements
7.1 Magnetic properties
7.1.1 General
The properties defined in 8.1.2 to 8.1.4 are applicable to products in the delivery conditions defined in
7.3. The magnetic properties shall be measured in accordance with EN 60404-2 for power frequencies or
IEC 60404-10 for medium frequencies.
For products supplied with insulation coating, the mass of the coating should be taken into account to
determine the magnetic properties.
7.1.2 Magnetic polarization
The specified minimum values of magnetic polarization at the peak magnetic field strength H of 800 A/m
and at the frequency specified in Table 1 for grain-oriented material shall be as given in Table 1.
The specified minimum values of magnetic polarization at a peak magnetic field strength of H 2 500 A/m,
5 000 A/m and 10 000 A/m and at the frequency specified in Table 2 for non-oriented material shall be
as given in Table 2.
7.1.3 Specific total loss
The specified values of maximum specific total loss shall be as given in Tables 1 and 2. The values in
Tables 1 and 2 reflect the aged conditions (see 9.3.1). For grain-oriented electrical steel they also apply
to test specimens that have received, after cutting, a stress relief heat treatment under conditions
specified by the manufacturer.
Depending on the thicknesses, the values are specified at 1,0 T for the non-oriented steel and at 1,0 T or
1,5 T for the grain-oriented material and at the frequency specified in Tables 1 and 2.
Annex B gives, fo
...