ASTM A720/A720M-02(2021)

Standard Test Method for Ductility of Nonoriented Electrical Steel

SIGNIFICANCE AND USE
4.1 This is a specialized bend test for nonoriented electrical steel not covered under the provisions of Test Methods E290.  
4.2 This test is applicable to nonoriented silicon steel such as described in Specifications A677 and A683 in commercial thicknesses.  
4.3 It is not intended to be applied to steels considered inherently ductile.
SCOPE
1.1 This test method covers determination of ductility utilizing Epstein test strips and a bending device for bending the strip over a predetermined radius. It is intended for commercial silicon-bearing steel sheet or strip of nonoriented types in the thickness range from 0.010 to 0.031 in. [0.25 to 0.79 mm], inclusive.  
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

Relations

• Refers: ASTM A677-16(2023) - Standard Specification for Nonoriented Electrical Steel Fully Processed Types
• Effective Date: 01-Dec-2023
• Refers: ASTM A683-16(2023) - Standard Specification for Nonoriented Electrical Steel, Semiprocessed Types
• Effective Date: 01-Dec-2023
• Refers: ASTM E290-13 - Standard Test Methods for Bend Testing of Material for Ductility
• Effective Date: 01-Apr-2013
• Refers: ASTM A34/A34M-06(2012) - Standard Practice for Sampling and Procurement Testing of Magnetic Materials
• Effective Date: 01-Nov-2012
• Refers: ASTM A677-12 - Standard Specification for Nonoriented Electrical Steel Fully Processed Types
• Effective Date: 01-Nov-2012
• Refers: ASTM A683-05(2010) - Standard Specification for Nonoriented Electrical Steel, Semiprocessed Types
• Effective Date: 01-Nov-2010
• Refers: ASTM A677-07 - Standard Specification for Nonoriented Electrical Steel Fully Processed Types
• Effective Date: 01-Nov-2007
• Refers: ASTM A34/A34M-06 - Standard Practice for Sampling and Procurement Testing of Magnetic Materials
• Effective Date: 01-Nov-2006
• Refers: ASTM A683-05e1 - Standard Specification for Nonoriented Electrical Steel, Semiprocessed Types
• Effective Date: 15-Aug-2005
• Refers: ASTM A683-05 - Standard Specification for Nonoriented Electrical Steel, Semiprocessed Types
• Effective Date: 15-Aug-2005
• Refers: ASTM A677-05 - Standard Specification for Nonoriented Electrical Steel Fully Processed Types
• Effective Date: 15-Jun-2005
• Refers: ASTM A677-05e1 - Standard Specification for Nonoriented Electrical Steel Fully Processed Types
• Effective Date: 15-Jun-2005
• Refers: ASTM E290-97a(2004) - Standard Test Methods for Bend Testing of Material for Ductility
• 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

Overview

ASTM A720/A720M-02(2021), Standard Test Method for Ductility of Nonoriented Electrical Steel, provides a specialized procedure to evaluate the ductility of nonoriented silicon-bearing electrical steel, particularly those used in commercial applications. This standard addresses materials and scenarios not covered by other ductility test methods, such as ASTM E290, and is specifically designed for silicon steel as specified in ASTM A677 and ASTM A683. It is important for manufacturers and quality control laboratories seeking to assess the mechanical resilience of nonoriented electrical steel in thicknesses ranging from 0.010 to 0.031 inches (0.25 to 0.79 mm).

Key Topics

• Applicability: The test is intended for nonoriented electrical steel, particularly silicon steel in commercial sheet or strip form. It is not suited for steels considered inherently ductile.
• Test Method: Utilizes Epstein test strips and a specialized bend testing apparatus. The specimen is bent repeatedly over a predetermined radius until a crack or rupture occurs.
• Specimen Preparation: Requires samples from multiple locations of a test lot and specifies orientation relative to the rolling direction for a comprehensive assessment.
• Measurement of Ductility: The result is determined by counting the number of 180° bend reversals the specimen withstands before failure.
• Units of Measurement: Provides for both customary (inch-pound) and SI units, but these are to be used separately to ensure standardization and compliance.
• Safety Considerations: Users are responsible for implementing appropriate safety, health, and environmental procedures when applying this standard.

Applications

This ductility test standard is crucial in several practical contexts, such as:

• Quality Assurance: Ensures that nonoriented silicon steels meet required ductility standards for reliability in end-use applications.
• Material Selection: Assists engineers and manufacturers in selecting steel grades suitable for electrical applications, such as transformer cores, by providing a quantitative measure of ductility.
• Process Control: Supports ongoing production processes by identifying variations in material properties related to ductility, allowing for timely adjustments.
• Research and Development: Facilitates the comparison and improvement of silicon steel formulations where ductility is a critical property.

Adhering to ASTM A720/A720M-02(2021) ensures consistency and reliability in test results, supporting both buyers and sellers of nonoriented electrical steels in verifying product quality.

Related Standards

When using ASTM A720/A720M-02(2021), consider referencing these related ASTM standards for a comprehensive approach to electrical steel testing and specification:

• ASTM E290 - Standard Test Methods for Bend Testing of Material for Ductility (covers general bend testing environments outside the scope of A720)
• ASTM A677 - Specification for Nonoriented Electrical Steel, Fully Processed Types
• ASTM A683 - Specification for Nonoriented Electrical Steel, Semiprocessed Types
• ASTM A34/A34M - Practice for Sampling and Procurement Testing of Magnetic Materials

Following these standards together enhances the reliability of electrical steel testing procedures, supporting robust supply chain quality and compliance with international trade requirements.

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Keywords: Nonoriented electrical steel, ductility test, silicon steel, ASTM A720, bend test method, Epstein strips, commercial steel sheet, mechanical properties, quality control, standard test method.

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: A720/A720M − 02 (Reapproved 2021)
Standard Test Method for
Ductility of Nonoriented Electrical Steel
This standard is issued under the fixed designationA720/A720M; 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 E290 Test Methods for Bend Testing of Material for Ductil-
ity
1.1 This test method covers determination of ductility uti-
lizing Epstein test strips and a bending device for bending the
3. Summary of Test Method
strip over a predetermined radius. It is intended for commercial
3.1 A test strip is placed in the special test apparatus
silicon-bearing steel sheet or strip of nonoriented types in the
designed to clamp one end of the specimen securely while the
thickness range from 0.010 to 0.031 in. [0.25 to 0.79 mm],
other end is free to move, but held in tension by a spring. The
inclusive.
specimen is repeatedly bent through 180° reversals until a
1.2 The values and equations stated in customary (cgs-emu
crack appears at the bend or until sudden failure occurs by
and inch-pound) or SI units are to be regarded separately as
complete rupture.The number of reversals until failure is taken
standard. Within this test method, SI units are shown in
as a measure of the ductility.
brackets. The values stated in each system may not be exact
equivalents; therefore, each system shall be used independently
4. Significance and Use
of the other. Combining values from the two systems may
4.1 This is a specialized bend test for nonoriented electrical
result in nonconformance with this test method.
steel not covered under the provisions of Test Methods E290.
1.3 This standard does not purport to address all of the
4.2 This test is applicable to nonoriented silicon steel such
safety concerns, if any, associated with its use. It is the
as described in Specifications A677 and A683 in commercial
responsibility of the user of this standard to establish appro-
thicknesses.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. 4.3 It is not intended to be applied to steels considered
1.4 This international standard was developed in accor-
inherently ductile.
dance with internationally recognized principles on standard-
5. Apparatus
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
5.1 The apparatus, Fig. 1, consists of a set of stationary jaws
mendations issued by the World Trade Organization Technical
and a movable arm to which is attached another set of jaws and
Barriers to Trade (TBT) Committee.
a spring.
5.1.1 The stationary jaws shall have working edges with
2. Referenced Documents
radii of approximately 0.2 in. [5 mm] over which the test
2.1 ASTM Standards:
specimen is bent. Stationary jaws shall be of the quick-
A34/A34M Practice for Sampling and Procurement Testing
clamping type.
of Magnetic Materials
5.1.2 The jaws attached to the movable arm shall allow the
A677 Specification for Nonoriented Electrical Steel Fully
specimen to move freely during bending.
Processed Types
5.1.3 The spring clamped to the free end of the specimen
A683 Specification for Nonoriented Electrical Steel, Semi-
shall provide sufficient tension in the specimen to localize the
processed Types
bend.
5.1.4 Design of the movable arm shall permit a rotation of
approximately 180°.
This test method is under the jurisdiction of ASTM Committee A06 on
Magnetic Properties and is the direct responsibility of Subcommittee A06.01 on Test
Methods.
6. Sampling
Current edition approved June 1, 2021. Published June 2021. Originally
6.1 Select samples from at least two well separated loca-
approved in 1975. Last previous edition approved in 2016 as A720/A720M – 02
ɛ1
(2016) . DOI: 10.1520/A0720_A0720M-
...