ASTM B958-08
(Specification)Standard Specification for Extra-High-Strength and Ultra-High-Strength Class A Zinc–5% Aluminum-Mischmetal Alloy-Coated Steel Core Wire for Use in Overhead Electrical Conductors
Standard Specification for Extra-High-Strength and Ultra-High-Strength Class A Zinc<span class='unicode'>–</span>5% Aluminum-Mischmetal Alloy-Coated Steel Core Wire for Use in Overhead Electrical Conductors
SCOPE
1.1 This specification covers round, extra-high-strength, and ultra-high-strength, Class A coated zinc–5 % aluminum-mischmetal (Zn–5Al–MM) alloy-coated, steel core wire for use in Overhead Electrical Conductors.
1.2 This specification covers wire of diameter from 0.0500 to 0.1900 in. inclusive or 1.27 to 4.82 mm inclusive .
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. 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 non-conformance with the 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:B958 −08
StandardSpecification for
Extra-High-Strength and Ultra-High-Strength Class A
Zinc–5% Aluminum-Mischmetal Alloy-Coated Steel Core
Wire for Use in Overhead Electrical Conductors
This standard is issued under the fixed designation B958; 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 E1277 Test Method for Chemical Analysis of Zinc-5 %
Aluminum-Mischmetal Alloys by ICP Emission Spec-
1.1 Thisspecificationcoversround,extra-high-strength,and
trometry
ultra-high-strength, Class A coated zinc–5 % aluminum-
E29 Practice for Using Significant Digits in Test Data to
mischmetal (Zn–5Al–MM) alloy-coated, steel core wire for
Determine Conformance with Specifications
use in Overhead Electrical Conductors.
2.2 Other Standard:
1.2 This specification covers wire of diameter from 0.0500
GF-1 Standard Practice for Determination of Cerium and
to 0.1900 in. inclusive or 1.27 to 4.82 mm inclusive .
Lanthanum Compositions in GalfanAlloy (5 %Al-0.04 %
1.3 The values stated in either SI units or inch-pound units 3
La- 0.04 % Ce-Bal SHG Zn)
are to be regarded separately as standard. The values stated in
each system may not be exact equivalents; therefore, each
3. Terminology
system shall be used independently of the other. Combining
3.1 Abbreviations:
values from the two systems may result in non-conformance
3.1.1 MM—mischmetal
with the standard.
3.1.2 Zn–5Al–MM—zinc–5% aluminum mischmetal alloy
1.4 This standard does not purport to address all of the
3.2 Definitions of Terms Specific to This Standard:
safety concerns, if any, associated with its use. It is the
3.2.1 Lot, n—Unless otherwise specified in the contract or
responsibility of the user of this standard to establish appro-
order, a lot shall consist of all coils of wire of the same
priate safety and health practices and determine the applica-
diameter and unit lengths submitted for inspection at the same
bility of regulatory limitations prior to use.
time.
2. Referenced Documents
3.2.2 Product Code, n—Defines product coating type, coat-
2.1 ASTM Standards:
ing class, and strength grade.
A90/A90M Test Method for Weight [Mass] of Coating on •Extra High Strength Grade Zn–5Al–MM, Class A Coated,
Iron and Steel Articles with Zinc or Zinc-Alloy Coatings
use Code MA4.
A370 Test Methods and Definitions for Mechanical Testing •Ultra High Strength Grade Zn–5Al–MM, Class A Coated,
of Steel Products
use Code MA5.
A751 Test Methods, Practices, and Terminology for Chemi-
cal Analysis of Steel Products
4. Ordering Information
B193 Test Method for Resistivity of Electrical Conductor
4.1 Orders for material under this specification shall include
Materials
the following information:
B750 Specification for GALFAN (Zinc-5 % Aluminum-
4.1.1 Quantity of each size,
Mischmetal) Alloy in Ingot Form for Hot-Dip Coatings
4.1.2 Wire diameter in inches or millimeter (Section 13),
4.1.3 Certification, if required (Section 18),
This test method is under the jurisdiction of ASTM Committee B01 on 4.1.4 Test report, if required (Section 18), and
Electrical Conductors and is the direct responsibility of Subcommittee B01.05 on
4.1.5 Package Size (Section 19).
Conductors of Ferrous Metals.
4.1.6 Product Code
Current edition approved Nov. 1, 2008. Published December 2008. DOI:
10.1520/B0958-08.
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 the International Lead Zinc Research Organization (ILZRO),
the ASTM website. 1822 NC Highway 54 East, Suite 120, Durham NC 27713, http://www.ilzro.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B958−08
TABLE 2 Grade 4 Extra-High-Strength Tensile Requirements
5. Materials and Manufacture
Specified Diameter, Stress Ultimate Elongation
5.1 The base metal shall be steel produced by the open-
in. at 1% Tensile in 10 in.,
hearth, electric furnace, or basic oxygen process.
Extension, Strength, min %
min, kpsi min, kpsi
5.2 The wire shall be cold drawn and coated with
0.0500 to 0.0899, incl 225 265 3.0
Zn–5Al–MM alloy to produce the desired properties. 0.0900 to 0.1199, incl 220 260 3.0
0.1200 to 0.1399, incl 215 255 3.5
0.1400 to 0.1900, incl 210 250 3.5
6. Chemical Composition
6.1 The steel shall conform to the requirements prescribed
TABLE 3 Grade 4 Extra-High-Strength Tensile Requirements
in Table 1.
(Metric)
6.2 Chemical analysis of the steel shall be conducted in
Specified Diameter, Stress Ultimate Elongation
accordance with Test Methods, Practices, and Terminology
mm at 1% Tensile in 250 mm,
A751.
Extension, Strength, min %
min, MPa min, MPa
6.3 The ingot form of zinc-5 % aluminum-mischmetal alloy
1.27 to 2.28, incl 1550 1825 3.0
2.29 to 3.04, incl 1515 1790 3.0
shall conform to Specification B750.
3.05 to 3.55, incl 1480 1760 3.5
6.3.1 For a two-step coating operation where the first
3.56 to 4.82, incl 1450 1725 3.5
coating is zinc (hot-dip galvanized or electro-galvanized), the
final bath may have an aluminum content of up to 7.2 %, to
prevent depletion of the aluminum content of the bath.
TABLE 4 Grade 5 Ultra-High-Strength Tensile Requirements
6.3.2 Method of Coating Material Analysis—RefertoSpeci-
Specified Diameter, Stress Ultimate Elongation
fication B750.
in. at 1% Tensile in 10 in.,
Extension, Strength, min %
min, kpsi min, kpsi
7. Tensile Test
0.0500 to 0.0899, incl 230 285 3.0
0.0900 to 0.1199, incl 225 275 3.0
7.1 The Zn–5Al–MM-coated steel core wire shall conform
0.1200 to 0.1399, incl 220 270 3.5
to the tensile and elongation requirements prescribed in Table
0.1400 to 0.1900, incl 215 265 3.5
2, Table 3, Table 4,or Table 5 depending on which strength
grade and unit base ordered.
TABLE 5 Grade 5 Ultra-High-Strength Tensile Requirements
7.2 Tensile tests shall be conducted in accordance with Test
(Metric)
Methods and Definitions A370, using the initial settings for
Specified Diameter, Stress Ultimate Elongation
determining stress at 1 % extension given in Table 6 or Table
mm at 1% Tensile in 250 mm,
7 of this specification. Extension, Strength, min %
min, MPa min, MPa
7.3 Test Specimens—The test specimens shall be free of
1.27 to 2.28, incl 1580 1965 3.0
2.29 to 3.04, incl 1550 1900 3.0
bendsorkinksotherthanthecurvatureresultingfromtheusual
3.05 to 3.55, incl 1515 1860 3.5
coiling operations.Any hand straightening necessary to permit
3.56 to 4.82, incl 1480 1825 3.5
insertion of the specimen in the jaws of the testing machine
shall be performed by drawing between wood blocks or by
some other equally satisfactory means.
TABLE 6 Initial Settings for Determining Stress at 1% Extension
7.4 The nominal diameter requested shall be used to deter- Specified Diameter, Initial Stress, Initial Setting
in. kpsi of Extensometer,
mine the applicable strength specification from the tables.
in./in.
0.0500 to 0.0899, incl 18 0.0005 (0.05 % extension)
8. Wrap Test 0.0900 to 0.1199, incl 36 0.0010 (0.10 % extension)
0.1200 to 0.1900, incl 54 0.0015 (0.15 % extension)
8.1 The material, as represented by the test specimens, shall
not fracture when the Zn–5Al–MM alloy-coated wire is
wrapped at a rate not exceeding 15 turns/min in a close helix
of at least eight turns around a cylindrical mandrel with a
9. Coating Test
diameter equal to four times the specified diameter of the wire
9.1 TheZn–5Al–MMalloy-coatedwireshallconformtothe
under test, 65%.
coating requirements prescribed in Table 8 or Table 9.
9.2 The coating test shall be conducted in accordance with
Test Method A90/A90M.
TABLE 1 Chemical Requirements
Element Composition, %
10. Adherence of Coating Test
Carbon 0.50 to 1.00
Manganese 0.40 to 1.30 10.1 TheZn–5Al–MMalloy-coatedwireshallbecapableof
Phosphorus, max 0.035
being wrapped in a close helix at a rate not exceeding 15
Sulfur, max 0.045
turns/min around a cylindrical mandrel having a diameter as
Silicon 0.15 to 0.60
prescribed in Table 10 or Table 11, without cracking or flaking
B958−08
TABLE 7 Initial Settings for Determining Stress at 1% Extension
11.3 Welding equipment and procedure shall be such that it
(Metric)
can be demonstrated that the ultimate tensile strength of a
Specified Diameter, Initial Stress, Initial Setting
finished wire specimen containing the welded section shall be
mm MPa of Extensometer,
not less than 96 % of the specified minimum stress at 1 %
mm/mm
extension.
1.27 to 2.28, incl 125 0.0005 (0.05 % extension)
2.29 to 3.04, incl 250 0.0010 (0.10 % extension)
11.4 A welded section shall not be required to meet the
3.05 to 4.82, incl 375 0.0015 (0.15 % extension)
stress at 1 % extension, elongation, and wrap tests.
TABLE 8 Zn-5Al–MM Alloy Coating 12. Density and Resistivity
Specified Diameter Area Density
12.1 For the purpose of calculating mass per unit length,
of Coated Wire, in. of Zn–5Al–MM Alloy Coating
cross sections, and so forth, the density of Zn–5Al–MM
min of Uncoated Wire Surface,
oz/ft
alloy-coated steel wire at 20°C shall be taken as 0.281 lb/in.
0.0500 to 0.0599, incl 0.60
(7780 kg/m ).
0.0600 to 0.0749,
...
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