1、Designation:A64097(Reapproved 2014)Standard Specification forZinc-Coated Steel Strand for Messenger Support of Figure 8Cable1This standard is issued under the fixed designation A640;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the
2、 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 two sizes of extra-high-strength grade of concentric-lay steel wire strand,composed ofse
3、ven,zinc-coated steel wires,specifically intended for use asthe supporting messenger in Figure 8-type communication andelectrical cables.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided f
4、or information onlyand are not considered standard.2.Referenced Documents2.1 ASTM Standards:2A90/A90M Test Method for Weight Mass of Coating onIron and Steel Articles with Zinc or Zinc-Alloy CoatingsA902 Terminology Relating to Metallic Coated Steel Prod-uctsB6 Specification for Zinc3.Terminology3.1
5、 DefinitionsSee Terminology A902 for definitions ofgeneral terminology relating to metallic coated steel products.4.Description4.1 Figure 8 cable consists of a plastic-sheathed communi-cation or electrical cable made with an integral supportingmessenger strand.The supporting messenger strand has apl
6、astic sheath with a narrow,longitudinal web connecting tothe plastic sheath of the cable.Generally the plastic sheath overthe supporting strand,the connecting web,and the plasticsheath over the cable are all applied by extruding in oneoperation.4.2 The galvanized steel strand used for the support me
7、s-senger of Figure 8-type cable is generally coated by floodingwith a sealing compound before the plastic sheath is applied(Note).It is generally preferred that this sealing compound beapplied to the individual wires during the stranding operationjust before the wires are laid together.This ensures
8、that allwires are completely covered and the interstices between thewires are sealed with a thermoplastic flooding compound toprevent intrusion of moisture under the plastic sheath.Some-times the thermoplastic material is only applied to the outsideof the finished strand.NOTE1The cable manufacturer
9、should advise the strand manufacturerof the plastic to be used for the sheath so that a sealing compound can beselected to avoid any adverse effects on the sheath.5.Ordering Information5.1 Orders for material under this specification shall includethe following information:5.1.1 Nominal strand diamet
10、er(Table 1),5.1.2 Quantity of each size of strand,length in feet(metres),5.1.3 Unit length(see 16.1),5.1.4 Sealing compound,if required,and the method ofapplication.Special requirements of sealing compound(Note),5.1.5 Package size if different from standard(Section 16),5.1.6 Special package marking(
11、see 16.4),and5.1.7 Inspection(Section 14).6.Materials and Manufacture6.1 The base metal of the wires shall be steel made by theopen-hearth,basic-oxygen,or electric-furnace process and ofsuch quality and purity that,when drawn to the size of wirespecified and coated with zinc,the finished strand and
12、theindividual wires shall be of uniform quality and have theproperties and characteristics as prescribed in this specifica-tion.6.2 The slab zinc,when used for the wire coating,shall beany grade of zinc conforming to Specification B6.7.Stranding7.1 Six wires shall be stranded with a uniform left-han
13、d layabout a center wire to form the completed strand.All wiresshall be stranded with uniform tension.Stranding shall be1This specification is under the jurisdiction of ASTM Committee A05 onMetallic-Coated Iron and Steel Products and is the direct responsibility ofSubcommittee A05.12 on Wire Specifi
14、cations.Current edition approved Aug.1,2014.Published August 2014.Originallyapproved in 1971.Last previous edition approved in 2009 as A640 97(2009)1.DOI:10.1520/A0640-97R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annu
15、al 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 sufficiently close to ensure no appreciable reduction in diam-eter when stressed t
16、o 10%of the specified strength.Aleft-handlay is defined as a counter-clockwise twist away from theobserver.7.2 The strand shall have a uniform pitch of not less than 14times nor more than 22 times the nominal strand diameter.7.3 All wires in the strand shall lie naturally in their truepositions in the completed strand and,when the strand is cut,the ends shall remain in position or be readily replaced by handand then remain in position.This shall be accomplished by ameans or process,such as prefo
