ASTM A721/A721M-02(2021)

Standard Test Method for Ductility of Oriented Electrical Steel

SIGNIFICANCE AND USE
4.1 This is a specialized bend test for grain-oriented steel not covered under the provisions of Test Methods E290.  
4.2 This test is applicable to grain-oriented silicon steel such as covered in Specification A876 in commercial thicknesses and widths up to 36 in. [910 mm].
SCOPE
1.1 This test method covers determination of the ductility of grain-oriented silicon steel by use of an apparatus known variously as a tinner's brake, hand folder, or an apron brake.  
1.2 The values and equations stated in customary (cgs-emu and inch-pound) or SI units are to be regarded separately as standard. Within this test method, SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with this test method.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-May-2021
• ICS: 77.140.50 - Flat steel products and semi-products
• Technical Committee: A06 - Magnetic Properties
• Drafting Committee: A06.01 - Test Methods

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: A721/A721M − 02 (Reapproved 2021)
Standard Test Method for
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Ductility of Oriented Electrical Steel
This standard is issued under the fixed designationA721/A721M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Summary of Test Method
3.1 A test specimen representing the full width of grain-
1.1 This test method covers determination of the ductility of
oriented steel to be tested is bent through an angle of about
grain-oriented silicon steel by use of an apparatus known
160° in a tinner’s brake. The number of breaks, or fractures,
variously as a tinner’s brake, hand folder, or an apron brake.
occurring along the bend determines the ductility class rating.
1.2 The values and equations stated in customary (cgs-emu
and inch-pound) or SI units are to be regarded separately as
4. Significance and Use
standard. Within this test method, SI units are shown in
4.1 This is a specialized bend test for grain-oriented steel
brackets. The values stated in each system may not be exact
not covered under the provisions of Test Methods E290.
equivalents; therefore, each system shall be used independently
4.2 Thistestisapplicabletograin-orientedsiliconsteelsuch
of the other. Combining values from the two systems may
as covered in Specification A876 in commercial thicknesses
result in nonconformance with this test method.
and widths up to 36 in. [910 mm].
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
5. Apparatus
responsibility of the user of this standard to establish appro-
5.1 The machine required to perform this test is known
priate safety, health, and environmental practices and deter-
variously as a tinner’s brake, hand folder, or an apron brake.
mine the applicability of regulatory limitations prior to use.
5.2 The brake shall be at least 36 in. [910 mm] wide with an
1.4 This international standard was developed in accor-
opening capacity of approximately 0.035 in. [0.9 mm].
dance with internationally recognized principles on standard-
5.2.1 The nose bar shall have a 0.031-in. [0.8-mm] radius.
ization established in the Decision on Principles for the
5.2.2 The bending bar must be movable through an angle of
Development of International Standards, Guides and Recom-
at least 160°.
mendations issued by the World Trade Organization Technical
5.2.3 The movable table or apron shall move around the end
Barriers to Trade (TBT) Committee.
of the nose bar at a distance of approximately 0.25 in. [6.35
mm].
2. Referenced Documents
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6. Test Specimen
2.1 ASTM Standards:
A34/A34M Practice for Sampling and Procurement Testing
6.1 Two specimens are required and they shall be selected
of Magnetic Materials
from the same general location as that of the magnetic test
A876 Specification for Flat-Rolled, Grain-Oriented, Silicon-
specimens in accordance with Practice A34/A34M.
Iron, Electrical Steel, Fully Processed Types
6.2 The specimens shall be cut transversely to the rolling
E290 Test Methods for Bend Testing of Material for Ductil-
direction and have a length equal to the sheet or strip width and
ity
a minimum dimension of 3 in. [80 mm] in the direction of
rolling.
6.3 The specimens shall be free of rust, ripples, and
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This test method is under the jurisdiction of ASTM Committee A06 on
scratches.
Magnetic Properties and is the direct responsibility of Subcommittee A06.01 on Test
Methods.
Current edition approved June 1, 2021. Published June 2021. Originally 7. Procedure
approved in 1975. Last previous edition approved in 2016 as A721/A721M – 02
7.1 The test specimen shall be at a temperature of 25 6 5°C
(2016). DOI: 10.1520/A0721_A0721M-02R21.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or at the start of the test.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
7.2 Insert the test specimen into the brake and clamp with
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. the direction of rolling perpendicular to the nose bar and 0.5 to
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A721/A721M − 02 (2021)
1.5 in. [12 to 40 mm] under the nose bar thereby allowing the 8.2 The class ratings shown are based on strip widths of 24
balance of the specimen width to r
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