ASTM A721/A721M-02(2021)
(Test Method)Standard Test Method for Ductility of Oriented Electrical Steel
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
- Technical Committee
- A06 - Magnetic Properties
- Drafting Committee
- A06.01 - Test Methods
Relations
- Effective Date
- 01-Apr-2017
- Effective Date
- 01-Apr-2013
- Effective Date
- 01-Nov-2012
- Effective Date
- 01-Nov-2012
- Effective Date
- 01-May-2009
- Effective Date
- 01-May-2009
- Refers
ASTM A34/A34M-06 - Standard Practice for Sampling and Procurement Testing of Magnetic Materials - Effective Date
- 01-Nov-2006
- Effective Date
- 01-Oct-2004
- Refers
ASTM A34/A34M-96 - Standard Practice for Sampling and Procurement Testing of Magnetic Materials - Effective Date
- 10-Oct-2001
- Refers
ASTM A34/A34M-01 - Standard Practice for Sampling and Procurement Testing of Magnetic Materials - Effective Date
- 10-Oct-2001
- Effective Date
- 01-Jan-1997
Overview
ASTM A721/A721M-02(2021): Standard Test Method for Ductility of Oriented Electrical Steel establishes a standardized procedure for assessing the ductility of grain-oriented silicon electrical steel. This method utilizes a specialized bend test performed with equipment such as a tinner’s brake, hand folder, or apron brake. The test is specially designed for grain-oriented steels, particularly those covered by ASTM Specification A876, with thicknesses and widths up to 36 inches (910 mm). The standard is maintained by ASTM International and developed in alignment with recognized international standardization principles.
Key Topics
Scope and Purpose
- Focuses exclusively on ductility determination for grain-oriented silicon steel.
- Not covered by more general bend test standards (e.g., ASTM E290).
- Suitable for samples up to 36 in. [910 mm] wide in commercial thicknesses.
Testing Apparatus
- Requires a tinner’s brake (or equivalent hand folder/apron brake) with an opening capacity of approximately 0.035 in. [0.9 mm].
- Testing utilizes a nose bar radius of 0.031 in. [0.8 mm] and allows bending to at least 160 degrees.
Specimen Preparation
- Two test specimens are prepared per lot, cut transversely to the steel’s rolling direction.
- Specimens must correspond in location to those used for magnetic testing and be free from rust, ripples, or scratches.
Test Procedure
- Each specimen is bent through approximately 160° at ambient temperature (25°C ± 5°C).
- The test observes and counts visible surface fractures along the bend without magnification.
Evaluation and Classification
- Specimens are classified into ductility classes (1 through 5) based on the number and extent of surface breaks.
- Higher class numbers indicate poorer ductility.
- For specimens less than 24 inches wide, results are normalized per standard instructions.
Units and Safety
- The standard presents values in both customary (inch-pound) and SI units but mandates each to be used independently to maintain compliance.
- Users are responsible for establishing adequate safety, health, and environmental procedures.
Applications
Quality Control in Electrical Steel Manufacturing
- Ensures the ductility of grain-oriented electrical steel used in transformers, generators, and electrical machinery, which is vital for durability and performance.
Material Procurement and Specification
- Offers a reliable method for producers and buyers to verify that silicon steel meets requisite ductility criteria as per industry and contract requirements.
Research and Product Development
- Facilitates the comparison of ductile properties among different batches or grades of grain-oriented electrical steel.
International Trade and Compliance
- Supports compliance with global trade regulations and technical barriers set by the World Trade Organization (WTO) through adherence to internationally recognized testing practices.
Related Standards
- ASTM A876: Specification for Flat-Rolled, Grain-Oriented, Silicon-Iron, Electrical Steel, Fully Processed Types
- ASTM A34/A34M: Practice for Sampling and Procurement Testing of Magnetic Materials
- ASTM E290: Test Methods for Bend Testing of Material for Ductility (for non-oriented materials)
- Additional cross-referenced standards and procedures from the ASTM Annual Book of Standards
Keywords: ASTM A721, ductility test, oriented electrical steel, silicon steel, grain-oriented steel, bend test, electrical steel standards, ASTM international, materials testing, quality control, transformer steel, electrical engineering materials
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Frequently Asked Questions
ASTM A721/A721M-02(2021) is a standard published by ASTM International. Its full title is "Standard Test Method for Ductility of Oriented Electrical Steel". This standard covers: 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.
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.
ASTM A721/A721M-02(2021) is classified under the following ICS (International Classification for Standards) categories: 77.140.50 - Flat steel products and semi-products. The ICS classification helps identify the subject area and facilitates finding related standards.
ASTM A721/A721M-02(2021) has the following relationships with other standards: It is inter standard links to ASTM A876-17, ASTM E290-13, ASTM A876-12, ASTM A34/A34M-06(2012), ASTM A876-09e1, ASTM A876-09, ASTM A34/A34M-06, ASTM E290-97a(2004), ASTM A34/A34M-96, ASTM A34/A34M-01, ASTM E290-97a. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
ASTM A721/A721M-02(2021) 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)
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
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
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
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
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