ASTM B279-98

Standard Test Method for Stiffness of Bare Soft Square and Rectangular Copper and Aluminum Wire for Magnet Wire Fabrication

SCOPE
1.1 This test method, known as the low-stress elongation (LSE) test, covers the procedure for determining the stiffness of bare soft square and rectangular copper and aluminum wire in terms of the permanent elongation resulting from the application of a stress of tensile.

General Information

• Status: Historical
• Publication Date: 09-Sep-1998
• ICS: 29.060.10 - Wires
• Technical Committee: B01 - Electrical Conductors
• Drafting Committee: B01.02 - Methods of Test and Sampling Procedure

Relations

• Replaced By: ASTM B279-04 - Standard Test Method for Stiffness of Bare Soft Square and Rectangular Copper and Aluminum Wire for Magnet Wire Fabrication (Withdrawn 2004)
• Effective Date: 01-Apr-2004
• Referred By: ASTM B324-01(2021) - Standard Specification for Aluminum Rectangular and Square Wire for Electrical Purposes
• Effective Date: 10-Sep-1998
• Referred By: ASTM D1676-17 - Standard Test Methods for Film-Insulated Magnet Wire
• Effective Date: 10-Sep-1998
• Referred By: ASTM B48-00(2021)e1 - Standard Specification for Soft Rectangular and Square Bare Copper Wire for Electrical Conductors
• Effective Date: 10-Sep-1998

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: B 279 – 98
Standard Test Method for
Stiffness of Bare Soft Square and Rectangular Copper and
Aluminum Wire for Magnet Wire Fabrication
This standard is issued under the fixed designation B 279; 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 retaining as much as possible the original curvature of the
package. Test specimens having the full cross-sectional area of
1.1 This test method, known as the low-stress elongation
the wire shall be used. The standard gage length for the
(LSE) test, covers the procedure for determining the stiffness
measurement of elongation of wire shall be 10 in. (254 mm).
of bare soft square and rectangular copper and aluminum wire
The total length of the specimens shall be at least equal to the
in terms of the permanent elongation resulting from the
gage length plus the length of wire required for the full use of
application of a tensile stress.
the grips employed.
1.2 The SI values for weighing the specimen are regarded as
the standard. The inch-pound values are to be regarded as
6. Procedure
standard and the SI units may be approximate for all other
6.1 Straighten the test specimens carefully by hand with a
properties.
minimum amount of distortion or cold work. Improperly
2. Referenced Document prepared test specimens often cause unsatisfactory test results.
6.2 Cut off a test specimen of sufficient length. Measure the
2.1 The following document of the issue in effect at the time
length to the nearest 0.01 in. (0.25 mm) with any measuring
of reference forms a part of this test method to the extent
device accurate to 0.1 % (Note 2). Weigh this specimen to the
referenced herein:
nearest 0.01 g on a balance accurate to 0.1 %. The pound (N)
2.2 ASTM Standards:
load required to apply a stress to the specimen equal to 15 000
E 4 Practices for Force Verification of Testing Machines
psi (103 MPa) for copper, and 8 000 psi (55 MPa) for
3. Significance and Use aluminum shall be obtained from the following:
3.1 This test method is designed as an inspection or accep- Requiredload, lb 5 W 3 102.74/L . Copper
tance test of new bare soft square and rectangular wire intended
N 5 W 311612.7/L8. Copper
for subsequent fabrication into magnet wire.
lb 5 W 3 180.5/L . Aluminum
NOTE 1—Since the applied unit stress and the time of application are
N 5 W 3 20401.9/L8. Aluminum
constant for all wire sizes, the test enables comparisons of hardness
(stiffness or springiness) to be made between wires of the same or different
where:
size on the basis of the permanent elongation resulting from the applica-
W 5 weight of specimen, g,
tion of a low unit stress.
L 5 length of weighed specimen, in., and
L8 5 length of weighed specimen, mm.
4. Apparatus
NOTE 2—To facilitate the cutting and measuring of the length of the test
4.1 Tensile testing machines used for the low-stress elonga-
specimen, a jig or set of vises with jaws of carefully predetermined
tion test shall conform to the requirements of Practices E 4.
di
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