ASTM_B_957_-_B_957M_-_16.pdf

Designation:B957/B957M16Standard Specification forExtra-High-Strength and Ultra-High-Strength Zinc-Coated(Galvanized)Steel Core Wire for Overhead ElectricalConductors1This standard is issued under the fixed designation B957/B957M;the number immediately following the designation indicates the yearof 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.Scope1.1 This specification covers round,extra-high-strength andultra-high-strength,Class A zinc-coated(galvanized),steelcore wire used for use in Overhead Electrical Conductors.1.2 This specification covers wire of diameter from 0.0500to 0.1900 in.inclusive or 1.27 to 4.82 mm inclusive.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2A90/A90M Test Method for Weight Mass of Coating onIron and Steel Articles with Zinc or Zinc-Alloy CoatingsA370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA751 Test Methods,Practices,and Terminology for Chemi-cal Analysis of Steel ProductsB6 Specification for ZincB193 Test Method for Resistivity of Electrical ConductorMaterialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 Lot,nUnless otherwise specified in the contract ororder,a lot shall consist of all coils of wire of the samediameter and unit lengths submitted for inspection at the sametime.3.1.2 Product Code,nDefines product coating type,coat-ing class and strength grade.3.1.2.1 Extra High Strength Grade Zinc,Class A Coateduse Code GA4.3.1.2.2 Ultra High Strength Grade Zinc,Class A Coateduse Code GA5.4.Ordering Information4.1 Orders for material under this specification shall includethe 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),and4.1.5 Package size(Section 19).4.1.6 Strength Grade.5.Materials and Manufacture5.1 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 toproduce the desired properties.5.3 The slab zinc used for coating shall be high grade orbetter,conforming to Specification B6.6.Chemical Composition6.1 The steel shall conform to the requirements prescribedin Table 1.6.2 Chemical analysis shall be conducted in accordancewith Test Methods,Practices,and Terminology A751.1This specification is under the jurisdiction of ASTM Committee B01 onElectrical Conductors and is the direct responsibility of Subcommittee B01.05 onConductors of Ferrous Metals.Current edition approved Dec.1,2016.Published December 2016.Originallyapproved in 2008.Last previous edition approved in 2008 as B957 081.DOI:10.1520/B0957_B0957M-16.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 7.Tensile Test7.1 The zinc-coated steel core wire shall conform to thetensile and elongation requirements prescribed in Table 2,Table 3,Table 4,or Table 5 depending on the strength gradeand unit base ordered.7.2 Tensile tests shall be conducted in accordance with TestMethods and Definitions A370,using the initial settings fordetermining stress at 1%extension given in Table 6 or Table7 of this specification.7.3 Test SpecimensThe test specimens shall be free ofbends or kinks other than the curvature resulting from the usualcoiling operations.Any hand straightening necessary to permitinsertion of the specimen in the jaws of the testing machineshall be performed by drawing between wood blocks or bysome other equally satisfactory means.7.4 The nominal diameter requested shall be used to deter-mine the applicable strength specification.8.Wrap Test8.1 The material,as represented by the test specimens,shallnot fracture when the galvanized wire is wrapped at a rate notexceeding 15 turns/min in a close helix of at least eight turnsaround a cylindrical mandrel with a diameter equal to fourtimes the specifi