ASTM B971-10
(Specification)Standard Specification for Silver-Coated Braid and Ribbon Flat Copper Wire intended for use in Electronic Application
Standard Specification for Silver-Coated Braid and Ribbon Flat Copper Wire intended for use in Electronic Application
ABSTRACT
This specification covers silver-coated copper braid and ribbon flat wire intended for electronic application. Two classes of silver-coated braid and ribbon flat copper wire are covered: Class A (annealed temper) and Class H (hard-drawn). The material shall be silver-coated flat wire of such quality and purity that the finished product shall meet the properties and characteristics prescribed in this specification. The specification covers tensile properties, electrical resistivity requirements, permissible variations in thickness, and permissible variations in width.
SCOPE
1.1 This specification covers silver-coated copper braid and ribbon flat wire intended for electronic application (Explanatory Note 1).
1.2 Two classes of silver-coated braid and ribbon flat copper wire are covered as follows:
1.2.1 Class A—Annealed temper.
1.2.2 Class H—Hard-drawn.
1.3 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.
1.3.1 Exceptions—The SI values for density, resistivity, and volume are to be regarded as standard.
1.4 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:B971 −10
StandardSpecification for
Silver-Coated Braid and Ribbon Flat Copper Wire intended
for use in Electronic Application
This standard is issued under the fixed designation B971; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 Other Standards:
NBS Handbook 100Copper Wire Tables
1.1 This specification covers silver-coated copper braid and
ribbon flat wire intended for electronic application (Explana-
3. Ordering Information
tory Note 1).
3.1 Ordersformaterialunderthisspecificationshallinclude
1.2 Twoclassesofsilver-coatedbraidandribbonflatcopper
the following information:
wire are covered as follows: 3.1.1 Quantity of each size,
1.2.1 Class A—Annealed temper. 3.1.2 Wire size-thickness and width in inches (see 5.4),
3.1.3 Class of wire (see 1.2),
1.2.2 Class H—Hard-drawn.
3.1.4 Type of copper, if special (see 4.2),
1.3 Thevaluesstatedininch-poundunitsaretoberegarded
3.1.5 Package size (see 10.1),
as standard. The values given in parentheses are mathematical
3.1.6 Special packaging marking, if required, and
conversions to SI units that are provided for information only
3.1.7 Place of inspection (see 7.1).
and are not considered standard.
4. Material
1.3.1 Exceptions—The SI values for density, resistivity, and
volume are to be regarded as standard.
4.1 The material shall be silver-coated flat wire (Explana-
1.4 This standard does not purport to address all of the toryNote1)ofsuchqualityandpuritythatthefinishedproduct
shall meet the properties and characteristics prescribed in this
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- specification.
priate safety and health practices and determine the applica-
4.2 Copper-Base Metal—The base metal shall be copper of
bility of regulatory limitations prior to use.
such quality and purity that the finished product shall have
properties and characteristics prescribed in this specification.
2. Referenced Documents
NOTE 1—Specifications B1, B3,or B49 define copper suitable for use.
2.1 ASTM Standards:
5. General Requirements (See Section 8)
B1Specification for Hard-Drawn Copper Wire
5.1 Temper—The silver-coated flat wire conductor shall be
B3Specification for Soft or Annealed Copper Wire
provided in either hard-drawn condition (Class H) or annealed
B49Specification for Copper Rod Drawing Stock for Elec-
condition (Class A) as agreed upon between the manufacturer
trical Purposes
and purchaser.
B193Test Method for Resistivity of Electrical Conductor
5.2 Tensile and Elongation (Explanatory Note 2):
Materials
5.2.1 Class A—The silver-coated copper flat wire in the
B258 Specification for Nominal Diameters and Cross-
annealed condition shall conform to the elongation require-
SectionalAreasofAWGSizesofSolidRoundWiresUsed
ments prescribed in Table 1. See Explanatory Note 3 for
as Electrical Conductors
equivalent round diameter calculations based on given thick-
nessandwidthdimensionsfortheflatwire.Forflatwirewhose
nominal equivalent round diameter is more than 0.001 in.
This test method is under the jurisdiction of ASTM Committee B01 on
(0.025 mm) greater than a size listed in Table 1, but less than
Electrical Conductors and is the direct responsibility of Subcommittee B01.04 on
that of the next larger size, the requirements of the next larger
Conductors of Copper and Copper Alloys.
Current edition approved April 1, 2010. Published May 2010. DOI: 10.1520/
size shall apply. No requirements for tensile strength are
B0971-10.
specified.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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 Available from National Technical Information Service (NTIS), 5285 Port
the ASTM website. Royal Rd., Springfield, VA 22161, http://www.ntis.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B971−10
A
TABLE 1 Tensile Properties TABLE 3 Permissible Variations in Thickness
Equivalent Area at 20°C Elongation in 10
Nominal Thickness Tolerance,
Round in.,
Range, Inch (mm) Inch (mm)
Diameter, in. min, %
cmils in.
0.0010 to 0.0014 +/- 0.0002
0.0641 4 110 0.00323 25
(0.025 to 0.036) (0.005)
0.0571 3 260 0.00256 25
0.0015 to 0.0019 +/- 0.0003
0.0508 2 580 0.00203 25
(0.038 to 0.048) (0.008)
0.0453 2 050 0.00161 25
0.0020 to 0.0049 +/- 0.0004
0.0403 1 620 0.00128 25
(0.051 to 0.124) (0.010)
0.0359 1 290 0.00101 25
0.0050 to 0.0100 +/- 0.0005
0.0320 1 020 0.000804 25
(0.127 to 0.254) (0.013)
0.0285 812 0.000638 25
0.0253 640 0.000503 25
0.0226 511 0.000401 25
TABLE 4 Permissible Variations in Width
0.0201 404 0.00317 20
0.0179 320 0.000252 20
Nominal Width Range, Tolerance,
0.0159 253 0.000199 20
Inch (mm) Inch (mm)
0.0142 202 0.000158 20
0.0126 159 0.000125 20
0.0100 to 0.0499 +/- 0.0013
0.0113 128 0.000100 20
(0.254 to 1.27) (0.033)
0.0100 100 0.0000785 20
0.0500 to 0.0699 +/- 0.0015
0.0089 79.2 0.0000622 15
(1.27 to 1.78) (0.038)
0.0080 64.0 0.0000503 15
0.0700 to 0.0999 +/- 0.0020
0.0071 50.4 0.0000396 15
(1.78 to 2.54) (0.051)
0.0063 39.7 0.0000312 15
0.1000 to 0.1249 +/- 0.0030
0.0056 31.4 0.0000246 15
(2.54 to 3.17) (0.076)
0.0050 25.0 0.0000196 15
0.1250 to 0.1500 +/- 0.0040
0.0045 20.2 0.0000159 15
(3.18 to 3.81) (0.102)
0.0040 16.0 0.0000126 15
A
See Explanatory Note 3 for equivalent round calculation.
5.6 Joints—Necessary joints in the wire and rods prior to
finalcoatinganddrawingshallbemadeinaccordancewiththe
best commercial practice. There shall be no uncoated joints in
5.2.2 Class H—The silver-coated copper flat wire in the
the final product.
hard-drawnconditionshallconformtoelongationrequirements
of1%minimumto5%maximum.Thetensilestrengthshallbe
5.7 Finish—The coating shall consist of a smooth continu-
55,000 psi (379 MPa) minimum.
ouslayer,firmlyadherenttothesurfaceofthecopper.Thewire
shall be free of all imperfections not consistent with the best
5.3 Resistivity (Explanatory Note 4)—The electrical resis-
commercial practice.
tivity of the coated wire at a temperature of 20°C shall not
exceed the values prescribed in Table 2.
6. Test Methods
5.4 Dimensions and Permissible Variations—The flat wire
6.1 Tensile Strength and Elongation (Explanatory Note 6):
sizes shall be expressed as the thickness and width of the wire
6.1.1 The tensile strength, expressed in pounds per square
indecimalfractionsofaninchtothenearest0.0001in.(0.0025
inch, shall be obtained by dividing the maximum load carried
mm). The silver-coated flat wire shall not vary from the
by the specimen during the tension test by the original
specified thickness and width by more than the amounts
cross-sectional area of the specimen. Tensile strength and
specified in Table 3 and Table 4, respectively.
elongation may be determined simultaneously on the same
5.5 Continuity of Coating—The silver coating shall be
specimen.
continuous. The continuity of coating on the flat wire shall be
6.1.2 The elongation shall be determined as the permanent
determined on representative samples taken before braiding
increase in length, expressed in percent of the original length,
applications or insulating. The continuity of coating shall be
due to the wire breaking in tension. The elongation of the flat
determinedbythehydrochloricacid-sodiumpolysulfidetestin
wire may be determined by measurements made between the
accordance with 6.4. Wire whose coating weight corresponds
jawsofthetensiletestingmachine.Thezerolengthshallbethe
to a thickness less than 40 µ in. (0.00004 in.) shall not be
distance between the jaws at the start of the tension test and be
subject to this test (Explanatory Note 5). The thickness of
asnear10in.(254mm)aspracticable.Thefinallengthshallbe
coating shall be determined in accordance withTest MethodA
the distance between the jaws at the time of rupture. The
as prescribed in Appendix X1.
fracture shall be between the jaws of the testing machine and
not closer than 1 in. (25.4 mm) to the jaw.
6.2 Resistivity (Explanatory Note 4)—The electrical resis-
TABLE 2 Electrical Resistivity Requirements
tivity of the material shall be determined in accordance with
Class of Wire Ω·lb/mile TestMethodB193.Thepurchasermayacceptcertificationthat
the wire was drawn from rod stock meeting the international
A 875.20
standard for annealed copper instead of resistivity tests on the
H 902.27
finished wire.
B971−10
6.3 Dimensional Measurements—Dimensional measure- action of the sodium polysulfide. Examine the specimen with
mentsforwidthandthicknessshallbemadewithamicrometer the unaided eye (normal spectacles excepted) against a white
caliperequippedwithaverniergraduatedin0.0001in.(0.0025 background. The specimens shall be considered to have failed
mm). Measurements shall be made on at least three places on if,bysuchblackeningexposedcopperisrevealed.Noattention
each unit selected for this test. Any measurement taken shall be paid to blackening within 0.5 in. (12.7 mm) of the cut
exceeding the dimensions and permissible variation require- end.
ments in 5.4 shall constitute failure to meet the dimensional
6.5 Finish—Surface-finishinspectionshallbemadewiththe
conformance criterion.
unaided eye (normal spectacles excepted).
6.4 Continuity of Coating:
6.4.1 Specimens:
7. Inspection
6.4.1.1 Length of Specimens—Test specimens shall each
7.1 General (Explanatory Note 9)—Unless otherwise speci-
have a length of about 6 in. (152 mm).They shall be tagged or
fied in the contract or purchaser order, the manufacturer shall
marked to correspond with the coil, spool, or reel from which
be responsible for the performance of all inspection and test
they were cut.
requirements specified.
6.4.1.2 Treatment of Specimens—Thoroughly clean the
7.1.1 All inspections and tests shall be made at the place of
specimens by immersion in a suitable organic solvent for at
manufacture unless otherwise especially agreed upon between
least 3 min; then remove and wipe dry with a clean, soft cloth
the manufacturer and the purchaser at the time of purchase.
(Caution: See Explanatory Note 7). Keep the specimens thus
7.1.2 The manufacturer shall afford the inspector represent-
cleaned wrapped in a clean, dry cloth until tested. Do not
ing the purchaser all reasonable manufacturer’s facilities to
handle that part of the specimen to be immersed in the test
satisfy him that the material is being furnished in accordance
solution. Take care to avoid abrasion by the cut ends.
with this specification.
6.4.2 Special Solutions:
7.1.3 Unless otherwise agreed upon between the purchaser
6.4.2.1 Sodium Polysulfide Solution (sp gr 1.142)—Make a
and the manufacturer, conformance of the wire to the various
concentrated solution by dissolving sodium sulfide crystals
requirementslistedinSection5shallbedeterminedonsamples
(cp) in distilled water until the solution is saturated at about
taken from each lot of wire presented for acceptance.
21°C, and adding sufficient flowers of sulfur (in excess of 250
7.1.4 The manufacturer shall, if requested prior to
g/L of solution) to provide complete saturation, as shown by
inspection, certify that all wire in the lot was made under such
the presence in the solution of an excess of sulfur after the
conditions that the product as a whole conforms to the
solution has been allowed to stand for at least 24 h. Make the
requirements of this specification as determined by regularly
test solution by diluting a portion of the concentrated solution
made and recorded tests.
with distilled water to a specific gravity of 1.135 to 1.145 at
15.6°C. The sodium polysulfide test solution should have
7.2 Definitions Applicable to Inspection:
sufficient strength to blacken thoroughly a piece of clean
7.2.1 lot—Any amount of wire of one type and size pre-
uncoated copper wire in 5 s.Aportion of the test solution used
sented for acceptance at one time.
for testing samples shall not be considered to be exhausted
7.2.2 Sample—A quantity of production units (coils, reels,
until it fails to blacken a piece of clean copper as described
andsoforth)selectedatrandomfromthelotforthepurposeof
(Explanatory Note 8):
determining conformance of the lot to the requirements of this
6.4.2.2 Hydrochloric Acid Solution (sp gr 1.088)—Dilute
specification.
commercial HCl (sp gr 1.12) with distilled water to a specific
7.2.3 Specimen—Alengthofwireremovedfortestpurposes
gravity of 1.088 measured at 15.6°C. A portion of the HCl
from any individual production unit of the sample.
solution having a volume of 180 mL shall be considered
7.3 Sample Size (Explanatory Note 9)—The number of
exhausted if it fails to remove within 15 s the discoloration of
production units in a sample shall be as follows:
the silver due to the polysulfide immersion.
7.3.1 A full (100 % inspection) will be completed at every
6.4.3 Procedure:
set-up prior to running the order.
6.4.3.1 Immersion in Polysulfide Solution—Immerse a
7.3.2 Forelongation,resistivity,dimensionalmeasurements,
length of at least 4.5 in. (114 mm) from each of the clean
continuity of coating, and thickness of coating determinations,
specimens for 30 s in the sodium polysulfide solution, de-
thesampleshallconsistofsequentialproductionunitsfromthe
scribed in 6.4.2.1, maintained at a temperature between 15.6
lot.
and 21°C.
7.3.3 For surface-finish inspection and for packaging in-
6.4.3.2 Washing—Aftertheimmersion,thoroughlywashthe
spection(whenspecifiedbythepurchaseratthetimeofplacing
specimensincleanwaterandwipedrywithaclean,softcloth.
the order) the sample shall consist of sequential production
6.4.3.3 Immersion in Hydrochloric Acid—After washing,
units from the lot.
immediately immerse the specimen 15 s in the HCl solution
described in 6.4.2.2, thoroughly wash in clean water, and wipe
8. Conformance Criteria (Explanatory Note 9)
dry with a clean, soft cloth.
6.4.3.4 Examination of Specimens—After immersion and 8.1 Any lot of wire, the samples of which comply with the
washing examine the specimens to ascertain if copper exposed conformance criteria of Section 5, shall be considered as
through openings in the silver coating has been blackened by complying to the requirements of this standard. Individual
B971−10
production units that fail to meet one or more of the require- 10. Packaging and Shipping
ments shall be rejected. If a failure of an individual production
10.1 Package sizes shall be agreed upon by t
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