ASTM B957/B957M-23

Standard Specification for Extra-High-Strength and Ultra-High-Strength Zinc-Coated (Galvanized) 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 zinc-coated (galvanized), steel core wire used for use in Overhead Electrical Conductors.  
1.2 This specification covers wire of diameter from 0.0500 in. to 0.1900 in. inclusive or 1.27 mm 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2023
• ICS: 77.140.65 - Steel wire, wire ropes and link chains
• Technical Committee: B01 - Electrical Conductors
• Drafting Committee: B01.05 - Conductors of Ferrous Metals

Relations

• Replaces: ASTM B957/B957M-22 - Standard Specification for Extra-High-Strength and Ultra-High-Strength Zinc-Coated (Galvanized) Steel Core Wire for Overhead Electrical Conductors
• Effective Date: 01-Oct-2023
• Refers: ASTM A370-24 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 01-Mar-2024
• Refers: ASTM A370-23 - Standard Test Methods and Definitions for Mechanical Testing of Steel Products
• Effective Date: 15-Sep-2023
• Referred By: ASTM B857-22 - Standard Specification for Shaped Wire Compact Concentric-Lay-Stranded Aluminum Conductors, Coated-Steel Supported (ACSS/TW)
• Effective Date: 01-Oct-2023
• Referred By: ASTM B232/B232M-22 - Standard Specification for Concentric-Lay-Stranded Aluminum Conductors, Coated-Steel Reinforced (ACSR)
• Effective Date: 01-Oct-2023
• Referred By: ASTM B856-22 - Standard Specification for Concentric-Lay-Stranded Aluminum Conductors, Coated Steel Supported (ACSS)
• Effective Date: 01-Oct-2023
• Referred By: ASTM B500/B500M-22 - Standard Specification for Metallic Coated or Aluminum Clad Stranded Steel Core for Use in Overhead Electrical Conductors
• Effective Date: 01-Oct-2023
• Referred By: ASTM B1006-17(2023) - Standard Specification for Electrical Overhead Conductor Code Word Names
• Effective Date: 01-Oct-2023
• Referred By: ASTM B711-22 - Standard Specification for Concentric-Lay-Stranded Aluminum-Alloy Conductors, Steel Reinforced (AACSR) (6201)
• Effective Date: 01-Oct-2023

Overview

ASTM B957/B957M-23 is the international standard specification for extra-high-strength and ultra-high-strength, Class A zinc-coated (galvanized), steel core wire designed for use in overhead electrical conductors. This standard addresses round steel wires with diameters ranging from 0.0500 in. to 0.1900 in. (1.27 mm to 4.82 mm), making them suitable for the demanding requirements of transmission and distribution power lines. Developed by ASTM International, this specification is integral to ensuring consistent mechanical and protective properties required for overhead conductor applications worldwide.

Key Topics

• Material Requirements: The base metal is steel produced through open-hearth, electric-furnace, or basic-oxygen processes and is cold drawn. The zinc used for coating is high-grade or better, ensuring strong corrosion resistance.
• Galvanized Zinc Coating: Class A zinc-coating is applied to provide reliable resistance against atmospheric corrosion, essential for long-life performance in outdoor environments.
• Mechanical Properties:
  • Both extra-high-strength (Grade 4, GA4) and ultra-high-strength (Grade 5, GA5) grades are covered.
  • Wire is subject to specific tensile and elongation requirements, tailored by diameter, ensuring high mechanical integrity for conductor cores.
• Testing and Quality Assurance:
  • Strict methods for tensile strength, elongation, coating weight, and adherence are outlined.
  • Includes wrap and mandrel tests to ensure ductility and the effectiveness of the zinc coating.
  • Diameter tolerances and acceptable variations are specified to ensure product fit and function.
• Ordering and Traceability:
  • Manufacturers must detail product diameter, quantity, certification requirements, package size, and strength grade on orders.
  • Each unit is tagged with critical information for traceability and quality management.

Applications

The ASTM B957/B957M-23 standard is crucial for industries involved in the manufacturing, installation, and maintenance of overhead electrical transmission and distribution lines. Practical applications include:

• Steel Core for Conductors: These wires serve as the reinforcing core for overhead conductors such as ACSR (Aluminum Conductor Steel Reinforced), improving both strength and sag performance.
• High Voltage Transmission: Its high mechanical strength makes it ideal for use in power grid infrastructure, especially in environments demanding enhanced durability and weather resistance.
• Corrosive and Outdoor Environments: The galvanized coating provides essential corrosion resistance, ensuring conductors remain operational and structurally sound throughout extended service in challenging exposures.

Using wires compliant with ASTM B957/B957M-23 enhances safety, reliability, and the operational lifespan of transmission systems, supporting critical infrastructure investment and maintenance strategies.

Related Standards

Professionals working with galvanized steel core wire for overhead conductors should be aware of the following related ASTM standards:

• ASTM A90/A90M: Test Method for Weight [Mass] of Coating on Iron and Steel Articles with Zinc or Zinc-Alloy Coatings.
• ASTM A370: Test Methods and Definitions for Mechanical Testing of Steel Products.
• ASTM A751: Test Methods and Practices for Chemical Analysis of Steel Products.
• ASTM B6: Specification for Zinc.
• ASTM B193: Test Method for Resistivity of Electrical Conductor Materials.
• ASTM E29: Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications.

Familiarity and compliance with these standards ensure products meet the specific performance, safety, and quality expectations required for overhead electrical conductor applications.

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Keywords: ASTM B957, galvanized steel core wire, overhead electrical conductors, extra-high-strength steel wire, ultra-high-strength steel wire, zinc-coated steel wire, GA4, GA5, transmission lines, corrosion resistance.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: B957/B957M − 23
Standard Specification for
Extra-High-Strength and Ultra-High-Strength Zinc-Coated
(Galvanized) Steel Core Wire for Use in Overhead Electrical
Conductors
This standard is issued under the fixed designation B957/B957M; 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 A751 Test Methods and Practices for Chemical Analysis of
Steel Products
1.1 This specification covers round, extra-high-strength and
B6 Specification for Zinc
ultra-high-strength, Class A zinc-coated (galvanized), steel
B193 Test Method for Resistivity of Electrical Conductor
core wire used for use in Overhead Electrical Conductors.
Materials
1.2 This specification covers wire of diameter from
E29 Practice for Using Significant Digits in Test Data to
0.0500 in. to 0.1900 in. inclusive or 1.27 mm to 4.82 mm
Determine Conformance with Specifications
inclusive.
1.3 The values stated in either SI units or inch-pound units 3. Terminology
are to be regarded separately as standard. The values stated in
3.1 Definitions of Terms Specific to This Standard:
each system may not be exact equivalents; therefore, each
3.1.1 lot, n—unless otherwise specified in the contract or
system shall be used independently of the other. Combining
order, a lot shall consist of all coils of wire of the same
values from the two systems may result in non-conformance
diameter and unit lengths submitted for inspection at the same
with the standard.
time.
1.4 This standard does not purport to address all of the
3.1.2 product code, n—defines product coating type, coating
safety concerns, if any, associated with its use. It is the
class and strength grade.
responsibility of the user of this standard to establish appro-
3.1.2.1 Extra High Strength Grade Zinc, Class A Coated—
priate safety, health, and environmental practices and deter-
use Code GA4.
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor-
3.1.2.2 Ultra High Strength Grade Zinc, Class A Coated—
dance with internationally recognized principles on standard-
use Code GA5.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
4. Ordering Information
mendations issued by the World Trade Organization Technical
4.1 Orders for material under this specification shall include
Barriers to Trade (TBT) Committee.
the following information:
4.1.1 Quantity of each size,
2. Referenced Documents
4.1.2 Wire diameter in inches or millimeter (Section 13),
2.1 ASTM Standards:
4.1.3 Certification, if required (Section 18),
A90/A90M Test Method for Weight [Mass] of Coating on
4.1.4 Test report, if required (Section 18),
Iron and Steel Articles with Zinc or Zinc-Alloy Coatings
4.1.5 Package size (Section 19), and
A370 Test Methods and Definitions for Mechanical Testing
4.1.6 Strength grade.
of Steel Products
1 5. Materials and Manufacture
This specification is under the jurisdiction of ASTM Committee B01 on
Electrical Conductors and is the direct responsibility of Subcommittee B01.05 on
5.1 The base metal shall be steel produced by the open-
Conductors of Ferrous Metals.
hearth, electric-furnace, or basic-oxygen process.
Current edition approved Oct. 1, 2023. Published October 2023. Originally
approved in 2008. Last previous edition approved in 2022 as B957/B957M – 22.
5.2 The wire shall be cold drawn and coated with zinc to
DOI: 10.1520/B0957_B0957M-23.
produce the desired properties.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
5.3 The slab zinc used for coating shall be high grade or
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. better, conforming to Specification B6.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B957/B957M − 23
TABLE 2 Grade 4 Extra-High-Strength Tensile Requirements
6. Chemical Composition
Stress at 1 % Ultimate Tensile Elongation
6.1 The steel shall conform to the requirements prescribed Specified
Extension, Strength, in 10 in.,
Diameter, in.
in Table 1.
min, kpsi min, kpsi min %
0.0500 to 0.0899, incl 225 265 3.0
6.2 Chemical analysis shall be conducted in accordance
0.0900 to 0.1199, incl 220 260 3.0
with Test Methods and Practices A751.
0.1200 to 0.1399, incl 215 255 3.5
0.1400 to 0.1900, incl 210 250 3.5
7. Tensile Test
7.1 The zinc-coated steel core wire shall conform to the
TABLE 3 Grade 4 Extra-High-Strength Tensile Requirements
ordered tensile and elongation requirements prescribed in
[Metric]
Table 2, Table 3, Table 4, or Table 5 and a minimum breaking
Specified Stress at Ultimate Tensile Elongation
strength (lb [N]) calculated from the minimum required tensile
Diameter, 1 % Extension, Strength, in 250 mm,
and nominal wire diameter. The wire tensile strength used to
mm min, MPa min, MPa min %
determine compliance to Table 2, Table 3, Table 4, or Table 5
1.27 to 2.28, incl 1550 1825 3.0
2.29 to 3.04, incl 1515 1790 3.0
shall be calculated using the actual wire breaking strength and
3.05 to 3.55, incl 1480 1760 3.5
the nominal finished diameter of the wire.
3.56 to 4.82, incl 1450 1725 3.5
7.2 Tensile tests shall be conducted in accordance with Test
Methods and Definitions A370, using the initial settings for
TABLE 4 Grade 5 Ultra-High-Strength Tensile Requirements
determining stress at 1 % extension given in Table 6 or Table
Stress at Ultimate Elongation
7 of this specification.
Specified
1 % Extension, Tensile in 10 in.
Diameter,
7.3 Test Specimens—The test specimens shall be free of min, kpsi Strength, min %
in.
min, kpsi
bends or kinks other than the curvature resulting from the usual
0.0500 to 0.0899, incl 230 285 3.0
coiling operations. Any hand straightening necessary to permit
0.0900 to 0.1199, incl 225 275 3.0
insertion of the specimen in the jaws of the testing machine
0.1200 to 0.1399, incl 220 270 3.5
shall be performed by drawing between wood blocks or by
0.1400 to 0.1900, incl 215 265 3.5
some other equally satisfactory means.
7.4 The nominal diameter requested shall be used to deter-
TABLE 5 Grade 5 Ultra-High-Strength Tensile Requirements
mine the applicable strength specification.
[Metric]
Stress Ultimate Elongation
8. Wrap Test
Specified
at 1 % Tensile Strength, in 250 mm,
Diameter,
Extension, min, MPa min %
8.1 The material, as represented by the test specimens, shall
mm
min, MPa
not fracture when the galvanized wire is wrapped at a rate not
1.27 to 2.28, incl 1580 1965 3.0
exceeding 15 turns/min in a helix of at least eight turns around
2.29 to 3.04, incl 1550 1900 3.0
a cylindrical mandrel with a diameter equal to four times the
3.05 to 3.55, incl 1515 1860 3.5
3.56 to 4.82, incl 1480 1825 3.5
specified diameter of the wire under test, 65 %. The edge-to-
edge spacing of consecutive turns shall not exceed two times
the diameter of the wire.
TABLE 6 Initial Settings for Determining Stress at 1 % Extension
Specified Initial Stress, Initial Setting
9. Coating Test
Diameter, kpsi of Extensometer,
9.1 The zinc-coated wire shall conform to the coating
in. in./in.
requirements prescribed in Table 8 or Table 9.
0.0500 to 0.0899, incl 18 0.0005 (0.05 % extension)
0.0900 to 0.1199, incl 36 0.0010 (0.10 % extension)
9.2 The coating test shall be conducted in accordance with
0.1200 to 0.1900, incl 54 0.0015 (0.15 % extension)
Test Method A90/A90M.
10. Adherence of Coating Test
coating to such an extent that any zinc can be removed by
rubbing with the bare fingers.
10.1 The zinc-coated wire shall be capable of being
wrapped in a close helix at a rate not exceeding 15 turns/min
11. Joints
around a cylindrical mandrel having a diameter as prescribed in
11.1 No joints shall be made in the finished wire.
Table 10 or Table 11, without cracking or flaking the zinc
11.2 Joints may be made at any stage of processing prior to
final cold drawing, by the electric butt-weld or flash-welding
TABLE 1 Chemical Requirements
process.
Element Composition, %
11.3 Welding equipment and procedure shall be such that it
Carbon 0.50 to 1.00
Manganese 0.30 to 1.30 can be demonstrated that the ultimate tensile strength of a
Phosphorus, max 0.035
finished wire specimen containing the welded section shall be
Sulfur, max 0.045
not less than 96 % of the specified minimum stress at 1 %
Silicon 0.15 to 1.20
extension.
B957/B957M − 23
TABLE 7 Initial Settings for Determining Stress at 1 % Extension TABLE 11 Mandrel Size for Adherence Test [Metric]
[Metric]
NOTE 1—Loosening or detachment during the adhesion test of
Specified Initial Stress, Initial Setting
superficial, small particles of zinc formed by mechanical polishing of the
Diameter, MPa of Extensometer,
surface of the zinc-coated wire shall not be considered cause for rejection.
mm mm/mm
Specified Ratio of Mandrel Diameter
1.27 to 2.28, incl 124 0.0005 (0.05 % extension)
Wire Diameter, to Wire Diameter
2.29 to 3.04, incl 248 0.0010 (0.10 % extension)
mm
3.05 to 4.82, incl 372 0.0015 (0.15 % extension)
1.27 to 3.55, inc
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: B957/B957M − 22 B957/B957M − 23
Standard Specification for
Extra-High-Strength and Ultra-High-Strength Zinc-Coated
(Galvanized) Steel Core Wire for Use in Overhead Electrical
Conductors
This standard is issued under the fixed designation B957/B957M; 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
1.1 This specification covers round, extra-high-strength and ultra-high-strength, Class A zinc-coated (galvanized), steel core wire
used for use in Overhead Electrical Conductors.
1.2 This specification covers wire of diameter from 0.0500 in. to 0.1900 in. inclusive or 1.27 mm 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
A90/A90M Test Method for Weight [Mass] of Coating on Iron and Steel Articles with Zinc or Zinc-Alloy Coatings
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A751 Test Methods and Practices for Chemical Analysis of Steel Products
B6 Specification for Zinc
B193 Test Method for Resistivity of Electrical Conductor Materials
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
This specification is under the jurisdiction of ASTM Committee B01 on Electrical Conductors and is the direct responsibility of Subcommittee B01.05 on Conductors
of Ferrous Metals.
Current edition approved Oct. 1, 2022Oct. 1, 2023. Published October 2022October 2023. Originally approved in 2008. Last previous edition approved in 20192022 as
B957/B957M – 19. DOI: 10.1520/B0957_B0957M-22.22. DOI: 10.1520/B0957_B0957M-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B957/B957M − 23
3.1.1 lot, n—unless otherwise specified in the contract or order, a lot shall consist of all coils of wire of the same diameter and
unit lengths submitted for inspection at the same time.
3.1.2 product code, n—defines product coating type, coating class and strength grade.
3.1.2.1 Extra High Strength Grade Zinc, Class A Coated—use Code GA4.
3.1.2.2 Ultra High Strength Grade Zinc, Class A Coated—use Code GA5.
4. Ordering Information
4.1 Orders for material under this specification shall include the following information:
4.1.1 Quantity of each size,
4.1.2 Wire diameter in inches or millimeter (Section 13),
4.1.3 Certification, if required (Section 18),
4.1.4 Test report, if required (Section 18),
4.1.5 Package size (Section 19), and
4.1.6 Strength grade.
5. Materials and Manufacture
5.1 The base metal shall be steel produced by the open-hearth, electric-furnace, or basic-oxygen process.
5.2 The wire shall be cold drawn and coated with zinc to produce the desired properties.
5.3 The slab zinc used for coating shall be high grade or better, conforming to Specification B6.
6. Chemical Composition
6.1 The steel shall conform to the requirements prescribed in Table 1.
6.2 Chemical analysis shall be conducted in accordance with Test Methods and Practices A751.
7. Tensile Test
7.1 The zinc-coated steel core wire shall conform to the ordered tensile and elongation requirements prescribed in Table 2, Table
3, Table 4, or Table 5 and a minimum breaking strength (lb [N]) calculated from the minimum required tensile and nominal wire
diameter. The wire tensile strength used to determine compliance to Table 2, Table 3, Table 4, or Table 5 shall be calculated using
the actual wire breaking strength and the nominal finished diameter of the wire.
7.2 Tensile tests shall be conducted in accordance with Test Methods and Definitions A370, using the initial settings for
determining stress at 1 % extension given in Table 6 or Table 7 of this specification.
TABLE 1 Chemical Requirements
Element Composition, %
Carbon 0.50 to 1.00
Manganese 0.30 to 1.30
Phosphorus, max 0.035
Sulfur, max 0.045
Silicon 0.15 to 1.20
B957/B957M − 23
TABLE 2 Grade 4 Extra-High-Strength Tensile Requirements
Stress at 1 % Ultimate Tensile Elongation
Specified
Extension, Strength, in 10 in.,
Diameter, in.
min, kpsi min, kpsi min %
0.0500 to 0.0899, incl 225 265 3.0
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
TABLE 3 Grade 4 Extra-High-Strength Tensile Requirements
[Metric]
Specified Stress at Ultimate Tensile Elongation
Diameter, 1 % Extension, Strength, in 250 mm,
mm min, MPa min, MPa min %
1.27 to 2.28, incl 1550 1825 3.0
2.29 to 3.04, incl 1515 1790 3.0
3.05 to 3.55, incl 1480 1760 3.5
3.56 to 4.82, incl 1450 1725 3.5
TABLE 4 Grade 5 Ultra-High-Strength Tensile Requirements
Stress at Ultimate Elongation
Specified
1 % Extension, Tensile in 10 in.
Diameter,
min, kpsi Strength, min %
in.
min, kpsi
0.0500 to 0.0899, incl 230 285 3.0
0.0900 to 0.1199, incl 225 275 3.0
0.1200 to 0.1399, incl 220 270 3.5
0.1400 to 0.1900, incl 215 265 3.5
TABLE 5 Grade 5 Ultra-High-Strength Tensile Requirements
[Metric]
Stress Ultimate Elongation
Specified
at 1 % Tensile Strength, in 250 mm,
Diameter,
Extension, min, MPa min %
mm
min, MPa
1.27 to 2.28, incl 1580 1965 3.0
2.29 to 3.04, incl 1550 1900 3.0
3.05 to 3.55, incl 1515 1860 3.5
3.56 to 4.82, incl 1480 1825 3.5
TABLE 6 Initial Settings for Determining Stress at 1 % Extension
Specified Initial Stress, Initial Setting
Diameter, kpsi of Extensometer,
in. in./in.
0.0500 to 0.0899, incl 18 0.0005 (0.05 % extension)
0.0900 to 0.1199, incl 36 0.0010 (0.10 % extension)
0.1200 to 0.1900, incl 54 0.0015 (0.15 % extension)
7.3 Test Specimens—The test specimens shall be free of bends or kinks other than the curvature resulting from the usual coiling
operations. Any hand straightening necessary to permit 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.
7.4 The nominal diameter requested shall be used to determine the applicable strength specification.
8. Wrap Test
8.1 The material, as represented by the test specimens, shall not fracture when the galvanized wire is wrapped at a rate not
exceeding 15 turns/min in a helix of at least eight turns around a cylindrical mandrel with a diameter equal to four times the
specified diameter of the wire under test, 65 %. The edge-to-edge spacing of consecutive turns shall not exceed two times the
diameter of the wire.
B957/B957M − 23
TABLE 7 Initial Settings for Determining Stress at 1 % Extension
[Metric]
Specified Initial Stress, Initial Setting
Diameter, MPa of Extensometer,
mm mm/mm
1.27 to 2.28, incl 124 0.0005 (0.05 % extension)
2.29 to 3.04, incl 248 0.0010 (0.10 % extension)
3.05 to 4.82, incl 372 0.0015 (0.15 % extension)
9. Coating Test
9.1 The zinc-coated wire shall conform to the coating requirements prescribed in Table 8 or Table 9.
9.2 The coating test shall be conducted in accordance with Test Method A90/A90M.
10. Adherence of Coating Test
10.1 The zinc-coated wire shall be capable of being wrapped in a close helix at a rate not exceeding 15 turns/min around a
cylindrical mandrel having a diameter as prescribed in Table 10 or Table 11, without cracking or flaking the zinc coating to such
an extent that any zinc can be removed by rubbing with the bare fingers.
11. Joints
11.1 No joints shall be made in the finished wire.
11.2 Joints may be made at any stage of processing prior to final cold drawing, by the electric butt-weld or flash-welding process.
11.3 Welding equipment and procedure shall be such that it can be demonstrated that the ultimate tensile strength of a finished
wire specimen containing the welded section shall be not less than 96 % of the specified minimum stress at 1 % extension.
11.4 A welded section shall not be required to meet the stress at 1 % extension, and wrap tests.
12. Density and Resistivity
12.1 For the purpose of calculating mass per unit length, cross sections, and so forth, the density of galvanized steel wire at 20 °C
...