ASTM A720-97
(Test Method)Standard Test Method for Ductility of Nonoriented Electrical Steel
Standard Test Method for Ductility of Nonoriented Electrical Steel
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 in. (0.25 mm) to 0.031 in. (0.79 mm), inclusive.
1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.3 The values stated in modified cgs are to be regarded as the standard. The values in parentheses are for information only.
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Standards Content (Sample)
Designation: A 720 – 97 An American National Standard
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
1
Ductility of Nonoriented Electrical Steel
This standard is issued under the fixed designation A 720; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope other end is free to move, but held in tension by a spring. The
specimen is repeatedly bent through 180° reversals until a
1.1 This test method covers determination of ductility uti-
crack appears at the bend or until sudden failure occurs by
lizing Epstein test strips and a bending device for bending the
complete rupture. The number of reversals until failure is taken
strip over a predetermined radius. It is intended for commercial
as a measure of the ductility.
silicon-bearing steel sheet or strip of nonoriented types in the
thickness range from 0.010 in. [0.25 mm] to 0.031 in. [0.79
4. Significance and Use
mm], inclusive.
4.1 This is a specialized bend test for nonoriented electrical
1.2 This standard does not purport to address all of the
steel not covered under the provisions of Test Methods E 290.
safety concerns, if any, associated with its use. It is the
4.2 This test is applicable to nonoriented silicon steel such
responsibility of the user of this standard to establish appro-
as described in Specifications A 677, A 677M, A 683, and
priate safety and health practices and determine the applica-
A 683M in commercial thicknesses.
bility of regulatory limitations prior to use.
4.3 It is not intended to be applied to steels considered
1.3 The values stated in either customary (cgs-emu and
inherently ductile.
inch-pound) units or SI units are to be regarded separately as
standard. Within this test method, the SI units are shown in
5. Apparatus
brackets. The values stated in each system are not exact
5.1 The apparatus, Fig. 1, consists of a set of stationary jaws
equivalents; therefore, each system shall be used independently
and a movable arm to which is attached another set of jaws and
of the other. Combining values from the two systems may
a spring.
result in nonconformance with this method.
5.1.1 The stationary jaws shall have working edges with
2. Referenced Documents radii of approximately 0.5 cm [5 mm] over which the test
specimen is bent. Stationary jaws shall be of the quick-
2.1 ASTM Standards:
clamping type.
A 34 Practice for Sampling and Procurement Testing of
2 5.1.2 The jaws attached to the movable arm shall allow the
Magnetic Materials
specimen to move freely during bending.
A 677 Specification for Nonoriented Electrical Steel Fully
2 5.1.3 The spring clamped to the free end of the specimen
Processed Types
shall provide sufficient tension in the specimen to localize the
A 677M Specification for Nonoriented Electrical Steel,
2 bend.
Fully Processed Types (Metric)
5.1.4 Design of the movable arm shall permit a rotation of
A 683 Specification for Nonoriented Electrical Steel, Semi-
2 approximately 180°.
processed Types
A 683M Specification for Nonoriented Electrical Steel,
6. Sampling
2
Semiprocessed Types (Metric)
6.1 Select samples from at least two well separated loca-
E 290 Test Methods for Bend Testing of Material for
tions in each test lot or lift.
3
Ductility
6.1.1 The test specimens may be cut from samples used for
the core loss or other tests in accordance with the practice in
3. Summary of Test Method
Practice A 34.
3.1 A test strip is placed in the special test apparatus
6.1.2 Cut test specimens from near each end of each sample
designed to clamp one end of the specimen securely while the
coil and from the middle and the end of each sample sheet.
1 7. Test Specimen
This test method is under the jurisdiction of ASTM Committee A-6 on
Magnetic Properties and is the direct responsibility of Subcommittee A06.01 on Test
7.1 The test specimens shall be about 3 cm [30 mm] in
Methods.
width and not less than 15 cm [150 mm] in length.
Current edition approved April 10, 1997. Published December 1997. Originally
7.2 The number of test specimens representing each test lot
published as A 720 – 75. Last previous edition A 720 – 91.
2
Annual Book of ASTM Standards, Vol 03.04.
shall not be less than ten.
3
Annual Book of ASTM Standards, Vol 03.01.
1
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A 720
8.3 Bend the specimen through 90° by use of the movable
arm and jaws, Fig. 2; then bend it through 180° in the reverse
direction. Again bend the specimen through 180° in the first
direction and continually through 180° reversals until a crack
appears at the bend or until sudden failure occurs by complete
rupture.
8.4 Each full 180° bend, including the first 90°
...
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