1、Designation:A421/A421M15American Association StateHighway and Transportation Officials StandardAASHTO No.:M 204Standard Specification forStress-Relieved Steel Wire for Prestressed Concrete1This standard is issued under the fixed designation A421/A421M;the number immediately following the designation
2、 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.This standard has been approved for use by agencies of
3、 the U.S.Department of Defense.1.Scope*1.1 This specification covers two types of stress-relievedround high-carbon steel wire commonly used in prestressedconcrete construction,as follows:1.1.1 Type BA wire is used for applications in whichcold-end deformation is used for anchoring purposes(ButtonAnc
4、horage),and1.1.2 Type WA wire is used for application in which the endsare anchored by wedges,and no cold-end deformation of thewire is involved(Wedge Anchorage).1.2 A supplementary requirement(S1)is provided for usewhere low-relaxation wire and relaxation testing for thatproduct is required by the
5、purchaser.The supplementaryrequirement applies only when specified in the purchase order.1.3 This specification is applicable for orders in eitherinch-pounds units(as Specification A421)or in SI units(asSpecification A421M).1.4 The values stated in either inch-pound or SI units are tobe regarded sep
6、arately as standard.Within the text,the SI unitsare shown in brackets.The values stated in each system maynot be exact equivalents;therefore,each system shall be usedindependently of the other.Combining values from the twosystems may result in non-conformance with the specification.2.Referenced Docu
7、ments2.1 ASTM Standards:2A370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA751 Test Methods,Practices,and Terminology for Chemi-cal Analysis of Steel ProductsE328 Test Methods for Stress Relaxation for Materials andStructures2.2 Military Standard:3MIL-STD-129 Marking for Ship
8、ment and Storage2.3 Federal Standard:3Fed.Std.No.123 Marking for Shipments(Civil Agencies)3.Ordering Information3.1 It shall be the responsibility of the purchaser to specifyall requirements that are necessary for material ordered to thisspecification.Such requirements shall include,but are notlimit
9、ed to,the following:3.1.1 Quantity lb kg,3.1.2 Nominal diameter,3.1.3 Name of material(uncoated stress-relieved steel wirefor prestressed concrete,Type BA or WA wire),3.1.4 If outside inspection is required(10.1),3.1.5 Packaging,3.1.6 Supplementary Requirement S1(if desired),and3.1.7 ASTM designatio
10、n and date of issue.4.Manufacture4.1 ProcessThe steel shall be made by any commerciallyaccepted process.4.2 Internal SoundnessA sufficient discard shall be madeto ensure freedom from injurious piping and undue segrega-tion.4.3 WireThe wire shall be cold-drawn to size and suitablystress-relieved afte
11、r cold drawing by a continuous heat treat-ment to produce the prescribed mechanical properties.5.Mechanical Property Requirements5.1 Tensile StrengthThe tensile strength of Type BA wireand Type WA wire shall conform to the requirements pre-scribed in Table 1,and shall be determined as prescribed inT
12、est Methods and Definitions A370,including Annex A4.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved Nov.1,2015.Published November 201
13、5.Originallyapproved in 1958.Last previous edition approved in 2010 as A421/A421M 10.DOI:10.1520/A0421_A0421M-15.2For 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 stan
14、dards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk,DODSSP,Bldg.4,SectionD,700RobbinsAve.,Philadelphia,PA19111-5098,http:/dodssp.daps.dla.mil.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor
15、Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.2 Yield Strength:5.2.1 The minimum yield strength for all wire,measured bythe 1.0%extension under load method,shall not be less than85%of the specified minimum tensile strength.5.2.2 The extension under load shall be measured by anex
16、tensometer calibrated with the smallest division not largerthan 0.0001 in./in.0.0001 mm/mm of gage length.5.2.3 The initial load corresponding to the initial stressprescribed in Table 2 shall be applied to the specimen,at whichtime the extensometer is attached and adjusted to a reading of0.001 in./in.0.001 mm/mm of gage length.The load shallthen be increased until the extensometer indicates an extensionof 1%.The load for this extension shall be recorded.The stresscorresponding to this load shall
