ASTM B973-10
(Specification)Standard Specification for Tin-Coated Braid and Ribbon Flat Copper Wire intended for use in Electronic Application
Standard Specification for Tin-Coated Braid and Ribbon Flat Copper Wire intended for use in Electronic Application
ABSTRACT
This specification covers tin-coated hard-drawn copper braid and ribbon flat wire intended for electronic application. The tin shall be electroplated for the coating and shall be commercially pure. For purposes of this specification, the tin shall be considered commercially pure if the total of other elements, exclusive of copper, does not exceed 1%. This specification covers electrical resistivity requirements, permissible variations in thickness, permissible variations in width, and limiting number of test specimens for coating test.
SCOPE
1.1 This specification covers tin-coated hard-drawn copper braid and ribbon flat wire intended for electronic application (Explanatory Note 1).
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.2.1 Exceptions—The SI values for density, resistivity, and volume are to be regarded as standard.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:B973 −10
StandardSpecification for
Tin-Coated Braid and Ribbon Flat Copper Wire intended for
use in Electronic Application
This standard is issued under the fixed designation B973; 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. Ordering Information
3.1 Orders for material under this specification shall include
1.1 This specification covers tin-coated hard-drawn copper
the following information:
braid and ribbon flat wire intended for electronic application
3.1.1 Quantity of each size,
(Explanatory Note 1).
3.1.2 Wire size-thickness and width in inches (see 5.3),
1.2 The values stated in inch-pound units are to be regarded
3.1.3 Type of copper, if special (see 4.2),
as standard. The values given in parentheses are mathematical
3.1.4 Package size (see 10.1),
conversions to SI units that are provided for information only
3.1.5 Special packaging marking, if required, and
and are not considered standard.
3.1.6 —Place of inspection (see 7.1).
1.2.1 Exceptions—The SI values for density, resistivity, and
volume are to be regarded as standard.
4. Material
1.3 This standard does not purport to address all of the 4.1 Tin for Coating—The tin shall be electroplated for the
safety concerns, if any, associated with its use. It is the coating and shall be commercially pure (Explanatory Note 1).
responsibility of the user of this standard to establish appro- For purposes of this specification, the tin shall be considered
priate safety and health practices and determine the applica- commercially pure if the total of other elements, exclusive of
bility of regulatory limitations prior to use. copper, does not exceed 1%. Not withstanding the previous
sentence, chemical analysis of the tin coating or of the tin used
2. Referenced Documents for coating shall not be required under this specification.
4.2 Copper-Base Metal—The base metal shall be copper of
2.1 ASTM Standards:
such quality and purity that the finished product shall have
B1 Specification for Hard-Drawn Copper Wire
properties and characteristics prescribed in this specification.
B3 Specification for Soft or Annealed Copper Wire
B49 Specification for Copper Rod Drawing Stock for Elec-
NOTE 1—Specifications B1, B3,or B49 defines copper suitable for use.
trical Purposes
B193 Test Method for Resistivity of Electrical Conductor
5. General Requirements (See Section 8)
Materials
5.1 Tensile and Elongation—The tin-coated copper flat wire
B258 Specification for Nominal Diameters and Cross-
in the hard drawn condition shall conform to elongation
SectionalAreasofAWGSizesofSolidRoundWiresUsed
requirements of 1% minimum to 5% maximum. The tensile
as Electrical Conductors
strength shall be 55 000 psi (379 MPa) minimum.
2.2 Other Standards:
5.2 Resistivity (Explanatory Note 3)—The electrical resis-
NBS Handbook 100 Copper Wire Tables
tivity of the coated wire at a temperature of 20°C shall not
exceed the values prescribed in Table 1.
5.3 Dimensions and Permissible Variations—The flat wire
This test method is under the jurisdiction of ASTM Committee B01 on
sizes shall be expressed as the thickness and width of the wire
Electrical Conductors and is the direct responsibility of Subcommittee B01.04 on
indecimalfractionsofaninchtothenearest0.0001in.(0.0025
Conductors of Copper and Copper Alloys.
Current edition approved April 1, 2010. Published May 2010. DOI: 10.1520/
mm). The tin-coated flat wire shall not vary from the specified
B0973-10.
thickness and width by more than the amounts specified in
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Table 2 and Table 3, respectively.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
5.4 Continuity of Coating—The tin coating shall be continu-
the ASTM website.
ous. The continuity of coating on the flat wire shall be
Available from National Technical Information Service (NTIS), 5301 Shawnee
Rd., Alexandria, VA 22312, http://www.ntis.gov. determined on representative samples taken before braiding
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B973−10
TABLE 1 Electrical Resistivity Requirements
the wire was drawn from rod stock meeting the international
Thickness Range, Resistivity at 20°C standard for annealed copper instead of resistivity tests on the
Inch (mm) Ω·lb/mile2
finished wire.
0.0008 to 0.0012 (0.020 to 0.031), incl 1006.0
6.3 Dimensional Measurements—Dimensional measure-
0.0013 to 0.0016 (0.033 to 0.041), incl 972.45
mentsforwidthandthicknessshallbemadewithamicrometer
0.0017 to 0.0024 (0.043 to 0.061), incl 961.76
caliper equipped with a vernier graduated in 0.0001 in. (0.0025
0.0025 to 0.0048 (0.064 to 0.122), incl 951.31
0.0049 to 0.0100 (0.125 to 0.254), incl 941.08
mm). Measurements shall be made on at least three places on
each unit selected for this test. Any measurement taken
exceeding the dimensions and permissible variation require-
TABLE 2 Permissible Variations in Thickness
ments in 5.4 shall constitute failure to meet the dimensional
Nominal Thickness Range, Tolerance,
conformance criterion.
Inch (mm) Inch (mm)
6.4 Continuity of Coating:
0.0010 to 0.0014 (0.025 to 0.036) +/- 0.0002 (0.005)
6.4.1 Specimens:
0.0015 to 0.0019 (0.038 to 0.048) +/- 0.0003 (0.008)
6.4.1.1 Length of Specimens—Test specimens shall have a
0.0020 to 0.0049 (0.051 to 0.124) +/- 0.0004 (0.010)
0.0050 to 0.0100 (0.127 to 0.254) +/- 0.0005 (0.013)
lengthofabout6in.(152mm).Theyshallbetaggedormarked
tocorrespondwiththecoil,spool,orreelfromwhichtheywere
cut.
TABLE 3 Permissible Variations in Width
6.4.1.2 Treatment of Specimens—The specimens shall be
Nominal Width Range, Tolerance,
thoroughly cleaned by immersion in a suitable organic solvent
Inch (mm) Inch (mm)
for at least 3 min; then removed and wiped dry with a clean,
0.0100 to 0.0499 (0.254 to 1.27) +/- 0.0013 (0.033) soft cloth ( Caution-see Explanatory Note 5). The specimens
0.0500 to 0.0699 (1.27 to 1.78) +/- 0.0015 (0.038)
thus cleaned shall be kept wrapped in a clean, dry cloth until
0.0700 to 0.0999 (1.78 to 2.54) +/- 0.0020 (0.051)
tested. That part of the specimen to be immersed in the test
0.1000 to 0.1249 (2.54 to 3.17) +/- 0.0030 (0.076)
solution shall not be handled. Care shall be taken to avoid
0.1250 to 0.1500 (3.18 to 3.81) +/- 0.0040 (0.102)
abrasion by the cut ends.
6.4.2 Special Solutions Required:
applications or insulating. The continuity of coating shall be 6.4.2.1 Hydrochloric Acid Solution (HCl) (sp gr 1.088)—
Commercial HCl (sp gr 1.12) shall be diluted with distilled
determined by the hydrochloric acid-sodium polysulfide test in
accordance with 6.4. water to a specific gravity of 1.088 measured at 15.6°C (60°F).
Aportion of HCl solution having a volume of 180 mLshall be
5.5 Joints—Necessary joints in the wire and rods prior to
considered to be exhausted when the number of test specimens
final coating and drawing shall be made in accordance with the
prescribed in Table 4 of a size as indicated in 6.4.3 have been
best commercial practice. There shall be no uncoated joints in
immersed in it for two cycles.
the final product.
6.4.2.2 Sodium Polysulfide Solution (sp gr 1.142) (Explana-
5.6 Finish—The coating shall consist of a smooth continu-
tory Note 6)—A concentrated solution shall be made by
ouslayer,firmlyadherenttothesurfaceofthecopper.Thewire
dissolving sodium sulfide crystals (cp) in distilled water until
shall be free of all imperfections not consistent with the best
commercial practice.
A
TABLE 4 Limiting Number of Test Specimens for Coating Test
6. Test Methods
Equivalent Round Maximum Number of
Nominal Diameter Specimens
6.1 Tensile Strength and Elongation (Explanatory Note 4):
to be Tested for 2
6.1.1 The tensile strength, expressed in pounds per square
Cycles
inch, shall be obtained by dividing the maximum load carried
in 180 mL of Acid
Solution
by the specimen during the tension test by the original
in. mm
cross-sectional area of the specimen. Tensile strength and
elongation may be determined simultaneously on the same
Under 0.0851 to Under 2.2 to 1.3, 6
0.0501, incl
specimen.
incl
6.1.2 The elongation of the flat wire may be determined by
measurements made between the jaws of the tensile testing
Under 0.0501 to Under 1.3 to 0.97, 10
0.0381, incl
machine. The zero length shall be the distance between the
incl
jaws at the start of the tension test and be as near 10 in. (254
mm) as practicable. The final length shall be the distance
Under 0.0381 to Under 0.97 to 0.76, 12
0.0301, incl
between the jaws at the time of rupture. The fracture shall be
incl
between the jaws of the testing machine and not closer than 1
in. (25.4 mm) to the jaw. Under 0.0301 to Under 0.76 to 0.076, 14
0.0030, incl
6.2 Resistivity (Explanatory Note 3)—The electrical resis-
incl
tivity of the material shall be determined in accordance with A
See Explanatory Note 2 for equivalent round calculation.
Test Method B193. The purchaser may accept certification that
B973−10
the solution is saturated at about 21°C (70°F), and adding 7.1.4 The manufacturer shall, if requested prior to
sufficient flowers of sulfur (in excess of 250 g/Lof solution) to inspection, certify that all wire in the lot was made under such
provide complete saturation, as shown by the presence in the conditions that the product as a whole conforms to the
solution of an excess of sulfur after the solution has been requirements of this specification as determined by regularly
allowed to stand for at least 24 h. The test solution shall be made and recorded tests.
made by diluting a portion of the concentrated solution with
7.2 Definitions Applicable to Inspection:
distilled water to a specific gravity of 1.135 to 1.145 at 15.6°C
7.2.1 lot—any amount of wire of one type and size pre-
(60°F). The sodium polysulfide test solution should have
sented for acceptance at one time.
sufficient strength to blacken thoroughly a piece of clean
7.2.2 sample—a quantity of production units (coils reels,
untinned copper wire in 5 s. The test solution used for testing
and so forth) selected at random from the lot for the p
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