1、Designation: B 957 08Standard Specification forExtra-High-Strength and Ultra-High-Strength Zinc-Coated(Galvanized) Steel Core Wire for Overhead ElectricalConductors1This standard is issued under the fixed designation B 957; the number immediately following the designation indicates the year oforigin
2、al adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This specification covers round, extra-high-strength andultra-hig
3、h-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 se
4、parately 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 conce
5、rns, 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:2A 90/A 90M Test Method for Weight Mass o
6、f Coating onIron and Steel Articles with Zinc or Zinc-Alloy CoatingsA 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 751 Test Methods, Practices, and Terminology forChemical Analysis of Steel ProductsB6 Specification for ZincB 193 Test Method for Resistivity of Electrical
7、ConductorMaterialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications3. Terminology3.1 Definitions of Terms Specific to This Standard:3.2 Lot, nUnless otherwise specified in the contract ororder, a lot shall consist of all coils of wire of the samediame
8、ter and unit lengths submitted for inspection at the sametime.3.3 Product Code, nDefines product coating type, coatingclass and strength grade. Extra High Strength Grade Zinc, Class A Coated, use CodeGA4. Ultra High Strength Grade Zinc, Class A Coated, use CodeGA5.4. Ordering Information4.1 Orders f
9、or 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 Strengt
10、h Grade5. 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, conformi
11、ng to Specification B6.1This test method 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 Nov. 1, 2008. Published December 2008.2For referenced ASTM standards, visit
12、 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-295
13、9, United States.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 A 751.7. Tensile Test7.1 The zinc-coated steel core wire shall conform to thetensile and el
14、ongation requirements prescribed in Table 2,Table 3, Table 4,orTable 5 depending on the strength gradeand unit base ordered.7.2 Tensile tests shall be conducted in accordance with TestMethods and Definitions A 370, using the initial settings fordetermining stress at 1 % extension given in Table 6 or
15、 Table7 of this specification.7.3 Test Specimens The 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
16、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 note
17、xceeding 15 turns/min in a close helix of at least eight turnsaround a cylindrical mandrel with a diameter equal to fourtimes the specified diameter of the wire under test, 6 5%.9. Coating Test9.1 The zinc-coated wire shall conform to the coatingrequirements prescribed in Table 8 or Table 9.9.2 The
18、coating test shall be conducted in accordance withTest Method A 90/A 90M.10. Adherence of Coating Test10.1 The zinc-coated wire shall be capable of beingwrapped in a close helix at a rate not exceeding 15 turns/minaround a cylindrical mandrel having a diameter as prescribed inTable 10 or Table 11, w
19、ithout cracking or flaking the zinccoating to such an extent that any zinc can be removed byrubbing with the bare fingers.11. Joints11.1 No joints shall be made in the finished wire.11.2 Joints may be made at any stage of processing prior tofinal cold drawing, by the electric butt-weld or flash-weld
20、ingprocess.11.3 Welding equipment and procedure shall be such that itcan be demonstrated that the ultimate tensile strength of afinished wire specimen containing the welded section shall benot less than 96 % of the specified minimum stress at 1 %extension.11.4 A welded section shall not be required
21、to meet thestress at 1 % extension, and wrap tests.12. Density and Resistivity12.1 For the purpose of calculating mass per unit length,cross sections, and so forth, the density of galvanized steel wireat 20C shall be taken as 0.281 lb/in.3(7780 kg/m3).12.2 A maximum resistivity of galvanized steel w
22、ire is notguaranteed, but a typical value of 0.19157 Vmm2/m may beTABLE 1 Chemical RequirementsElement Composition, %Carbon 0.50 to 1.00Manganese 0.40 to 1.30Phosphorus, max 0.035Sulfur, max 0.045Silicon 0.15 to 0.60TABLE 2 Grade 4 Extra-High-Strength Tensile RequirementsSpecifiedDiameter, in.Stress
23、 at 1%Extension,min, kpsiUltimate TensileStrength,min, kpsiElongationin 10 in.,min %0.0500 to 0.0899, incl 225 265 3.00.0900 to 0.1199, incl 220 260 3.00.1200 to 0.1399, incl 215 255 3.50.1400 to 0.1900, incl 210 250 3.5TABLE 3 Grade 4 Extra-High-Strength Tensile Requirements(Metric)SpecifiedDiamete
24、r,mmStress at1% Extension,min, MPaUltimate TensileStrength,min, MPaElongationin 250 mm,min %1.27 to 2.28, incl 1550 1825 3.02.29 to 3.04, incl 1515 1790 3.03.05 to 3.55, incl 1480 1760 3.53.56 to 4.82, incl 1450 1725 3.5TABLE 4 Grade 5 Ultra-High-Strength Tensile RequirementsSpecifiedDiameter,in.Str
25、ess at1% Extension,min, kpsiUltimateTensile Strength,min, kpsiElongationin 10 in.min %0.0500 to 0.0899, incl 230 285 3.00.0900 to 0.1199, incl 225 275 3.00.1200 to 0.1399, incl 220 270 3.50.1400 to 0.1900, incl 215 265 3.5TABLE 5 Grade 5 Ultra-High-Strength Tensile Requirements(Metric)SpecifiedDiame
26、ter,mmStressat 1% Extension,min, MPaUltimateTensile Strength,min, MPaElongationin 250 mm,min %1.27 to 2.28, incl 1580 1965 3.02.29 to 3.04, incl 1550 1900 3.03.05 to 3.55, incl 1515 1860 3.53.56 to 4.82, incl 1480 1825 3.5TABLE 6 Initial Settings for Determining Stress at 1% ExtensionSpecifiedDiamet
27、er,in.Initial Stress,kpsiInitial Settingof Extensometer,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)B957082used for calculating purposes. For conversion to other units ofconductivity o
28、r resistivity, refer to Test Method B 193.13. Dimensions and Permissible Variations13.1 The specified diameter of the zinc-coated wire fromSection 4 shall be expressed in decimal fractions of an inch tofour decimal places, or in millimeters to two decimal places.13.2 To determine the applicable tole
29、rance range from Table12 or Table 13, round the specified diameter to the nearest0.001 in. (0.01 mm), in accordance with the rounding methodof Practice E29.13.3 Measure the largest and smallest diameter taken at thesame cross section rounded to the nearest 0.001 in. (0.01 mm)in accordance with the r
30、ounding method of Practice E29.Calculate the average of the two measurements. The calculatedvalue shall not differ from the specified diameter by more thanthe applicable tolerance range shown in Table 12 or Table 13.14. Workmanship, Finish, and Appearance14.1 The zinc coating shall be reasonably smo
31、oth, continu-ous, of reasonably uniform thickness, and free of imperfectionsnot consistent with good commercial practice.15. Number of Tests and Retests15.1 One test specimen shall be taken from each 5000 lb(2500 kg) or fraction thereof in the inspection lot.15.2 Each specimen shall be tested for co
32、mpliance withSections 7, 8, 10, and 13. At least half of the specimens shallbe tested for compliance with Section 9.15.3 Should one or more of the test specimens fail any ofthe tests specified, the nonconforming coil or coils may beTABLE 7 Initial Settings for Determining Stress at 1% Extension(Metr
33、ic)SpecifiedDiameter,mmInitial Stress,MPaInitial Settingof Extensometer,mm/mm1.27 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)TABLE 8 Zinc CoatingSpecified Diameterof Coated Wire,in.Area Densityof Zinc Coa
34、ting, min of UncoatedWire Surface,oz/ft20.0500 to 0.0599, incl 0.600.0600 to 0.0749, incl 0.650.0750 to 0.0899, incl 0.700.0900 to 0.1039, incl 0.750.1040 to 0.1199, incl 0.800.1200 to 0.1399, incl 0.850.1400 to 0.1799, incl 0.900.1800 to 0.1900, incl 1.00TABLE 9 Zinc Coating (Metric)Specified Diame
35、terof Coated Wire,mmArea Densityof Zinc Coating, min ofUncoated Wire Surface,g/m21.27 to 1.52, incl 1831.53 to 1.90, incl 1981.91 to 2.28, incl 2142.29 to 2.64, incl 2292.65 to 3.04, incl 2443.05 to 3.55, incl 2593.56 to 4.57, incl 2744.58 to 4.82, incl 305TABLE 10 Mandrel Size for Adherence TestNOT
36、E 1Loosening or detachment during the adhesion test of super-ficial, small particles of zinc formed by mechanical polishing of thesurface of the zinc-coated wire shall not be considered cause for rejection.Specified WireDiameter,in.Ratio of Mandrel Diameterto Wire Diameter0.0500 to 0.1399, incl 40.1
37、400 to 0.1900, incl 5TABLE 11 Mandrel Size for Adherence Test (Metric)NOTE 1Loosening or detachment during the adhesion test of super-ficial, small particles of zinc formed by mechanical polishing of thesurface of the zinc-coated wire shall not be considered cause for rejection.SpecifiedWire Diamete
38、r,mmRatio of Mandrel Diameterto Wire Diameter1.27 to 3.55, incl 43.56 to 4.82, incl 5TABLE 12 Permissible Variations in Diameter of Zinc-CoatedSteel WireNOTE 1It is recognized that the surface of zinc coatings, particularlythose produced by the hot-dip method of coating, are not perfectly smoothand
39、devoid of irregularities. If the tolerances shown in the table are rigidlyapplied to such irregularities that are inherent to the product, unjustifiedrejections of wire that would actually be satisfactory for use could occur.It is intended that these tolerances be used in gaging the wires where ther
40、eis a minimum of such diameter irregularities due to galvanizing.Specified Diameter, in. Permissible Variation, in.Plus Minus0.0500 to 0.0749, incl 0.0015 0.0010.0750 to 0.1199, incl 0.002 0.0020.1200 to 0.1399, incl 0.003 0.0020.1400 to 0.1900, incl 0.004 0.003TABLE 13 Permissible Variations in Dia
41、meter of Zinc-CoatedSteel Wire (Metric)NOTE 1It is recognized that the surface of zinc coatings, particularlythose produced by the hot-dip method of coating, are not perfectly smoothand devoid of irregularities. If the tolerances shown in the table are rigidlyapplied to such irregularities that are
42、inherent to the product, unjustifiedrejections of wire that would actually be satisfactory for use could occur.It is intended that these tolerances be used in gaging the wires where thereis a minimum of such diameter irregularities due to galvanizing.Specified Diameter, mm Permissible Variation, mmP
43、lus Minus1.27 to 2.28, incl 0.038 0.0252.29 to 3.04, incl 0.051 0.0513.05 to 3.55, incl 0.076 0.0513.56 to 4.82, incl 0.102 0.076B957083removed and the balance of the lot subjected to retests. Forretest purposes, two additional coils for each 5000 lbs (2500kg) in the lot shall be sampled and tested
44、for the property inwhich the original sample failed to comply.15.4 Should any of the retest specimens fail to meet theproperties specified, the lot represented by the test specimensshall be rejected.15.5 Instead of rejecting the entire lot as provided inParagraph 15.4, the producer may test specimen
45、s from everycoil in the lot for the property in which failure occurred andreject only the nonconforming coils.16. Inspection16.1 Unless otherwise specified in the contract or purchaseorder, the manufacturer shall be responsible for the perfor-mance of all inspection and test requirements specified.1
46、6.2 All inspections and tests shall be made at the place ofmanufacture unless otherwise especially agreed upon betweenthe manufacturer and the purchaser at the time of the purchase.16.3 The manufacturer shall afford the inspector represent-ing the purchaser all reasonable manufacturers facilities to
47、satisfy him that the material is being furnished in accordancewith this specification.17. Rejection and Rehearing17.1 Material that fails to conform to the requirements ofthis specification shall be rejected. Rejection should be re-ported to the producer or supplier promptly and in writing. Incase o
48、f dissatisfaction with the results of the test, the produceror supplier may make claim for a rehearing.18. Certification18.1 When specified in the purchase order or contract, aproducers or suppliers certification shall be furnished to thepurchaser showing that the material was manufactured,sampled,
49、tested and inspected in accordance with this specifi-cation and has been found to meet the requirements. Whenspecified in the purchase order or contract, a report of the testresults shall be furnished.19. Package and Package Marking19.1 The unit lengths shall be as specified in the contract ororder. Length tolerances shall be 6 2 % unless otherwisespecified by the purchaser. (See Explanatory Note 1.)19.2 Package dimensions, kind of package (coils, reels, orreel-less coils), and quantity of wire in each package shall beagreed upon between the manufacturer and the purcha
