1、This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(
2、TBT)Committee.Designation:A421/A421M-21American Association StateHighway and Transportation Officials StandardAASHTO No.:M 204NTERNATIONALStandard Specification forStress-Relieved Steel Wire for Prestressed Concrete1This standard is issued under the fixed designation A421/A421M;the number immediatel
3、y 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(e)indicates an editorial change since the last revision or reapproval.This standard has been app
4、roved for use by agencies of the U.S.Department of Defense.1.Scope*mendations issued by the World Trade Organization Technical1.1 This specification covers two types of stress-relievedBarriers to Trade(TBT)Committee.round high-carbon steel wire used in prestressed concrete2.Referenced Documentsconst
5、ruction,as follows:2.1 ASTM Standards:21.1.1 Type BA wire is used for applications in whichA370 Test Methods and Definitions for Mechanical Testingcold-end deformation is used for anchoring purposes(Buttonof Steel ProductsAnchorage),andA751 Test Methods and Practices for Chemical Analysis of1.1.2 Ty
6、pe WA wire is used for application in which the endsSteel Productsare anchored by wedges,and no cold-end deformation of theE328 Test Methods for Stress Relaxation for Materials andwire is involved(Wedge Anchorage).Structures1.2 A supplementary requirement(S1)is provided for use2.2 Military Standard:
7、3where low-relaxation wire and relaxation testing for thatMIL-STD-129 Marking for Shipment and Storageproduct is required by the purchaser.The supplementary2.3 Federal Standard:requirement applies only when specified in the purchase orderFed.Std.No.123 Marking for Shipments(Civil Agencies)or contrac
8、t.3.Ordering Information1.3 This specification is applicable for orders in either3.1 Orders for stress-relieved steel wire under this specifi-inch-pounds units(as Specification A421)or in SI units(asSpecification A421M).cation shall contain the following information:3.1.1 Quantity(feet metres),1.4 T
9、he values stated in either inch-pound or SI units are to3.1.2 Nominal diameter(inches millimetres),be regarded separately as standard.Within the text,the SI units3.1.3 Type BA or WA wire,andare shown in brackets.The values stated in each system may3.1.4 ASTM designation A421 A421Mand year of issue.n
10、ot be exact equivalents;therefore,each system shall be used3.2 The purchaser shall have the option to specify additionalindependently of the other.Combining values from the tworequirements,including but not limited to,the following:systems may result in non-conformance with the specification.3.2.1 S
11、ampling-number of test specimens(9.1),1.5 The text of this specification references notes and3.2.2 Requirements for inspection(10.1),footnotes which provide explanatory material.These notes and3.2.3 Package marking(13.2),footnotes(excluding those in tables)shall not be considered as3.2.4 Relaxation
12、evidence on similarly dimensioned wire ofrequirements of the specification.the same grade(S1.5.1),and1.6 This international standard was developed in accor-3.2.5 Other special requirements,if any.dance with internationally recognized principles on standard-4.Manufactureization established in the Dec
13、ision on Principles for theDevelopment of International Standards,Guides and Recom-4.1 Process-The steel shall be made by any commerciallyaccepted process.2 For referenced ASTM standards,visit the ASTM website,www.astm.org,orThis specification is under the jurisdiction of ASTM Committee A01 on Steel
14、,contact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStainless Steel and Related Alloys and is the direct responsibility of SubcommitteeStandards volume information,refer to the standards Document Summary page onA01.05 on Steel Reinforcement.the ASTM website.Current edition appro
15、ved May 1.2021.Published May 2021.Originally3 Available from Standardization Documents Order Desk,DODSSP.Bldg.4,approved in 1958.Last previous edition approved in 2015 as A421/A421M-15.Section D,700 Robbins Ave.,Philadelphia,PA 19111-5098,http:/DOL:10.1520WA0421_A0421M-21dodssp.daps.dla.mil.*A Summa
16、ry of Changes section appears at the end of this standardCopyright ASTM Intemational,100 Barr Harbor Drive,PO Box C700.West Conshohocken.PA 19428-2959.United States1A421/A421M-21TABLE 1 Tensile Strength Requirements6.Diameter and Permissible VariationsNominalTensile Strength,min,psi MPaDiameter6.1 W
17、ire meeting the requirements of this specification isType BAType WAin.mmnormally ordered in the nominal diameters shown in Table 1.0.1924.88125000017256.2 The diameter of the wire shall not vary from the nominal0.1964.981240000【165525000017250.2506.35240000165524000016551diameter specified by more t
18、han+0.002 in.0.05 mm.0.2767.012350001620j23500016206.3 The wire shall not be out-of-round by more than 0.002AThis size is not commonly fumnished in Type BA wire.in.0.05mm7.Workmanship and FinishTABLE 2 Yield Strength Requirements7.1 Cast-A wire test specimen having a chord length of 60NominalMinimum
19、 Stress at 1Diameter,Initial Stress,Extension,psi MPain.1500 mmshall have an offset at the center of the chord ofpsi MPain.mmType BAType WAnot more than 3 in.75 mm.This is equivalent to a chord of0.192【4.881290002001A2125001465an arc of a circle not less than 25 ft 7.6 min diameter.0.1964.9829000200
20、204000140721250014657.2 Type BA Wire-Type BA wire shall be of suitable quality0.250【6.3529000200204000140720400014070.2767.01129000200119975013771997501377to permit cold forming of button heads for anchorage.SplittingA This size is not commonly fumnished in Type BA wire.shall not be considered a cau
21、se for rejection if the buttonanchorage is capable of developing the specified minimumtensile strength of the wire.7.3 The wire shall be free of kinks.4.2 Internal Soundness-A sufficient discard shall be madeto ensure freedom from injurious piping and undue segrega-7.4 The wire shall be furnished in
22、 firmly tied coils having aminimum inside diameter of 48 in.1200 mm.Each coil shalltion.be of one continuous length.4.3 Wire-The wire shall be cold-drawn to size and suitablystress-relieved after cold drawing by a continuous heat treat-7.5 There shall be no welds or joints in the finished wire.ment
23、to produce the prescribed mechanical properties.Any welds or joints made during manufacture to enablecontinuity of operations shall be removed.5.Mechanical Property Requirements7.6 The wire shall not be oiled or greased.Slight rusting,5.1 Tensile Strength-The tensile strength of Type BA wireprovided
24、 it is not sufficient to cause pits visible to a person withand Type WA wire shall conform to the requirements pre-normal or corrected vision,shall not be cause for rejection.scribed in Table 1,and shall be determined as prescribed in7.7 Temper colors which result from the stress-relievingTest Metho
25、ds and Definitions A370.including Annex A4.operation are considered normal for the appearance of the5.2 Yield Strength:finished wire5.2.1 The minimum yield strength for all wire,measured bythe 1.0 extension under load method,shall not be less than8.Chemical Requirements85 of the specified minimum te
26、nsile strength.8.1 Variations in manufacturing processes and equipment5.2.2 The extension under load shall be measured by anamong wire manufacturers necessitate the individual selectionextensometer calibrated with the smallest division not largerof an appropriate chemical composition at the discreti
27、on of thethan 0.0001 in./in.0.0001 mm/mmof gauge length.manufacturer.5.2.3 The initial load corresponding to the initial stress8.2 Phosphorus and sulfur values shall not exceed theprescribed in Table 2 shall be applied to the test specimen,atfollowing:which time the extensometer is attached and adju
28、sted to aPhosphorus0.040%reading of 0.001 in./in.0.001 mm/mmof gauge length.TheSulfur0.050%load shall then be increased until the extensometer indicates anextension of 1%The load for this extension shall be recorded.8.3 The purchaser shall have the right to make an analysisThe stress corresponding t
29、o this load shall meet the require-from finished wire representing each heat of steel.Samples forments for stress at 1 extension prescribed in Table 2.analysis shall be obtained by milling the wire in such a manner5.3 Elongation-The total elongation under load of all wireas to obtain a sample repres
30、entative of the entire cross sectionshall not be less than 4.0%when measured in a gauge lengthPrior to milling,the surface shall be cleaned to remove allof 10 in.250 mm.The elongation shall be determined by anforeign matter.All such individual determinations shall notextensometer which is placed on
31、the test specimen after a loadvary from the limits shown in 8.2 by more than 0.008%corresponding to the initial stress prescribed in Table 2 is8.4 For referee purposes,Test Methods,Practices,andapplied.If the fracture takes place outside of the gauge lengthTerminology A751 shall be applied.and the e
32、longation so measured meets the minimumrequirements,no further testing shall be required.If the9.Samplingelongation is less than the minimum requirements,the test shall9.1 Unless otherwise agreed upon between the manufacturerbe considered an invalid test and a retest made.and the purchaser,one test
33、specimen shall be taken from eachA421/A421M-2110 coils or less in a lot(Note 1)and tested to determinean electronic data interchange(EDI)transmission shall becompliance with Sections 5,6,and 7.regarded as having the same validity as a counterpart printed inthe certifiers facility.The content of the
34、EDI transmittedNorE 1-The termlotmeans all the coils of wire of the same nominalwire size contained in an individual shipping release or shipping order.document shall meet the requirements of the invoked ASTMstandard(s)and conform to any existing EDI agreement be-10.Inspectiontween the purchaser and
35、 the manufacturer.Notwithstanding the10.1 Inspection of the stress-relieved steel wire shall beabsence of a signature,the organization submitting the EDIagreed upon between the purchaser and the manufacturer astransmission is responsible for the content of the report.part of the purchase order or co
36、ntract.NorE 2-The industry definition as invoked here is:EDI is thecomputer-to-computer exchange of business information in a standard11.Rejectionformat such as ANSI ASC X12.11.1 Unless otherwise specified,any rejection based on tests13.Packaging and Package Markingmade in accordance with this speci
37、fication shall be reported to13.1 The type of wire,size of the wire,ASTM designationthe manufacturer within a reasonable length of time.A421 A421M,heat number,and name of the manufacturershall be marked on a tag securely attached to each coil of wire12.Certification13.2 When specified in the purchas
38、e order or contract,and12.1 At the time of shipment,the purchaser shall befurnished with a written certification that specimens represent-for direct procurement by or direct shipment to the U.S.Government,marking for shipment shall be in accordance withing each lot of wire have been either tested or
39、 inspected asFed.Std.No.123 for civil agencies and MIL-STD-129 forrequired in this specification and the requirements have beensatisfied.The certification shall include ASTM designationmilitary agencies.A421 A421M,year of issue,and revision letter,if any.14.Keywords12.2 A Material Test Report,Certif
40、icate of Inspection,or14.1 cold-drawn wire;low-relaxation wire;prestressed con-similar document printed from or used in electronic form fromcrete;steel wire(tendon):stress-relieved wireSUPPLEMENTARY REQUIREMENTSS1.LOW-RELAXATION WIRE AND RELAXATION TESTINGThe following supplementary requirement shal
41、l apply only when specified in the purchase order orcontract.S1.1 ScopeS1.5 Conditions of Relaxation TestS1.1.1 This supplementary requirement delineates onlyS1.5.1 If required,relaxation evidence shall be providedthose details which are peculiar to low-relaxation wire,and tofrom the manufacturers r
42、ecords of tests on similarly dimen-the method of relaxation testing related to single wire tendonssioned wire of the same grade.having properties generally as described in Specification A421/A421M.S1.5.2 The temperature of the test specimen shall be main-tained at683.5202Cl.S1.2 Test MethodS1.5.3 Th
43、e test specimen shall not be subjected to anyS1.2.1 Low-relaxation wire shall be tested as prescribed inloading prior to the relaxation test.Test Methods E328.S1.5.4 The initial load shall be applied uniformly over aS1.3 Relaxation Propertiesperiod of not less than 3 minutes and not more than 5 minu
44、tes,and the gauge length shall be maintained constant;loadS1.3.1 Low-relaxation wire shall meet the mechanical prop-relaxation readings shall commence 1 minute after applicationerty requirements of this specification,with the added require-of the total load.ment that relaxation after 1000 h under th
45、e conditions ofSection S1.5 shall not be more than 2.5 when initially loadedS1.5.5 Overstressing of the test specimen during the loadingto 70 of specified minimum tensile strength or not more thanoperation shall not be permitted.3.5 when loaded to 80%of specified minimum tensileS1.5.6 The duration o
46、f the test shall be 1000 h or a shorterstrength of the wireperiod extrapolated to 1000 h which can be shown by recordsS1.4 Yield Strengthto provide similar relaxation values.S1.5.7 The test gauge length shall be at least 60 times theS1.4.1 Yield strength of low-relaxation wire as described innominal
47、 diameter.5.2 shall not be less than 90 of the specified minimum tensilestrength of the wire.4A421/A421M-21SUMMARY OF CHANGESCommittee A0l has identified the location of selected changes to this standard since the last issue(A421/A421M-15)that may impact the use of this standard.(Approved May 1,2021
48、.)(1)Added 1.5.(2)Revised Section3,5.2.3,7.1,7.2,7.7,10.1,and12.1.ASTM Intemational takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard.Users of this standard are expressly advised that determination of the validity of any suc
49、h patent rights,and the riskof infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised,either reapproved or withdrawn.Your comments are invited ei
50、ther for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of theresponsible technical committee,which you may attend.If you feel that your comments have not received a fair he
51、aring you shouldmake your views known to the ASTM Committee on Standards,at the address shown below.This standard is copyrighted by ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.Individual reprints(single or multiple copies)of this standard may be
52、 obtained by contacting ASTM at the aboveaddress or at 610-832-9585(phone),610-832-9555(fax),or serviceastm.org(e-mail);or through the ASTM website(www.astm.org).Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center,222Rosewood Drive,Danvers,MA 01923,Tel:(978)646-2600;http:/
