1、Designation: A421/A421M 10American Association StateHighway and Transportation Officials StandardAASHTO No.: M 204Standard Specification forUncoated Stress-Relieved Steel Wire for PrestressedConcrete1This standard is issued under the fixed designation A421/A421M; the number immediately following the
2、 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.This standard has been approved for u
3、se by agencies of the Department of Defense.1. Scope*1.1 This specification covers two types of uncoated stress-relieved round high-carbon steel wire commonly used inprestressed linear concrete construction, as follows:1.1.1 Type BA wire is used for applications in which cold-end deformation is used
4、 for anchoring purposes (ButtonAnchorage), and1.1.2 Type WA wire is used for application in which theends are anchored by wedges, and no cold-end deformation ofthe wire is involved (Wedge Anchorage).1.2 A supplementary requirement (S1) is provided for usewhere low-relaxation wire and relaxation test
5、ing for thatproduct is required by the 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 i
6、nch-pound or SI units are tobe regarded separately 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-con
7、formance with the standard.2. Referenced Documents2.1 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
8、Military Standard:3MIL-STD-129 Marking for Shipment 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 thisspecificat
9、ion. Such requirements shall include, but are notlimited 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 Supplem
10、entary Requirement S1 (if desired), and3.1.7 ASTM designation and date of issue.4. Manufacture4.1 ProcessThe steel shall be made by the electric-arcfurnace, basic-oxygen, or open-hearth process.4.2 Internal SoundnessA sufficient discard shall be madeto ensure freedom from injurious piping and undue
11、segrega-tion.4.3 WireThe wire shall be cold-drawn to size and suitablystress-relieved after 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 c
12、onform to the requirements pre-scribed in Table 1, and shall be determined as prescribed inTest 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 Subcomm
13、itteeA01.05 on Steel Reinforcement.Current edition approved Nov. 1, 2010. Published December 2010. Originallyapproved in 1958. Last previous edition approved in 2005 as A421/A421M 05.DOI: 10.1520/A0421_A0421M-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cus
14、tomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dla
15、.mil.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2 Yield Strength:5.2.1 The minimum yield strength for all wire, measured bythe 1.0 % extension under load method
16、, shall not be less than85 % of the specified minimum tensile strength.5.2.2 The extension under load shall be measured by anextensometer 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 stressprescrib
17、ed 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 stre
18、sscorresponding to this load shall meet the requirements forstress at 1 % extension prescribed in Table 2.5.3 ElongationThe total elongation under load of all wireshall not be less than 4.0 % when measured in a gage length of10 in. 250 mm. The elongation shall be determined by anextensometer which i
19、s placed on the test specimen after a loadcorresponding to the initial stress prescribed in Table 2 isapplied. If the fracture takes place outside of the gage lengthand the elongation so measured meets the minimum require-ments, no further testing shall be required. If the elongation isless than the
20、 minimum requirements, the test shall be consid-ered an invalid test and a retest made.6. Diameter and Permissible Variations6.1 Wire meeting the requirements of this specification isnormally ordered in the nominal diameters shown in Table 1.6.2 The diameter of the wire shall not vary from the nomin
21、aldiameter specified by more than 60.002 in. 60.05 mm.6.3 The wire shall not be out-of-round by more than 0.002in. 0.05 mm.7. Workmanship and Finish7.1 CastA wire sample having a chord length of 60 in.1500 mm shall have an offset at the center of the chord of notmore than 3 in. 75 mm. This is equiva
22、lent to a chord of an arcof a circle not less than 25 ft 7.6 m in diameter.7.2 Type BA WireType BA wire shall be of suitablequality to permit cold forming of button heads for anchorage.Splitting shall not be considered a cause for rejection if thebutton anchorage is capable of developing the minimum
23、required tensile strength of the wire.7.3 The wire shall be free of kinks.7.4 The wire shall be furnished in firmly tied coils having aminimum inside diameter of 48 in. 1200 mm. Each coil shallbe of one continuous length.7.5 There shall be no welds or joints in the finished wire.Any welds or joints
24、made during manufacture to enablecontinuity of operations shall be removed.7.6 The wire shall not be oiled or greased. Slight rusting,provided it is not sufficient to cause pits visible to a person withnormal or corrected vision, shall not be cause for rejection.7.7 Temper colors which result from t
25、he stress-relievingoperation are considered normal for the finished appearance ofthis wire.8. Chemical Requirements8.1 Variations in manufacturing processes and equipmentamong wire manufacturers necessitate the individual selectionof an appropriate chemical composition at the discretion of themanufa
26、cturer.8.2 Phosphorus and sulfur values shall not exceed thefollowing:PhosphorusSulfur0.040 %0.050 %8.3 The purchaser shall have the right to make an analysisfrom finished wire representing each heat of steel. Samples foranalysis shall be obtained by milling the wire in such a manneras to obtain a s
27、ample representative of the entire cross section.Prior to milling, the surface shall be cleaned to remove allforeign matter. All such individual determinations shall notvary from the limits shown in 8.2 by more than 0.008 %.8.4 For referee purposes, Test Methods, Practices, andTerminology A751 shall
28、 be applied.9. Sampling9.1 Unless otherwise agreed upon between the manufacturerand the purchaser, one test specimen shall be taken from each10 coils or less in a lot (Note 1) and tested to determinecompliance with 5.1, 5.2, 5.3, 6, and 7.1.NOTE 1The term “lot” means all the coils of wire of the sam
29、e nominalwire size contained in an individual shipping release or shipping order.10. Inspection10.1 The purchaser shall state at the time of order whetheroutside inspection is required. If outside inspection is required,the manufacturer shall afford the inspector representing thepurchaser all reason
30、able facilities to satisfy the inspector thatthe material is being furnished in accordance with this speci-fication. All tests and inspections shall be made at the place ofmanufacture prior to shipment, unless otherwise agreed upon atthe time of purchase, and shall be so conducted withoutunnecessari
31、ly interfering with manufacturing operations.TABLE 1 Tensile Strength RequirementsNominalDiameter,in. mmTensile Strength, min, psi MPaType BA Type WA0.192 4.88A250 000 17250.196 4.98 240 000 1655 250 000 17250.250 6.35 240 000 1655 240 000 16550.276 7.01 235 000 1620 235 000 1620AThis size is not co
32、mmonly furnished in Type BA wire.TABLE 2 Yield Strength RequirementsNominalDiameter,in. mmInitial Stress,psi MPaMinimum Stress at 1 %Extension, psi MPaType BA Type WA0.192 4.88 29 000 200A212 500 14650.196 4.98 29 000 200 204 000 1407 212 500 14650.250 6.35 29 000 200 204 000 1407 204 000 14070.276
33、7.01 29 000 200 199 750 1377 199 750 1377AThis size is not commonly furnished in Type BA wire.A421/A421M 10211. Rejection11.1 Unless otherwise specified, any rejection based on testsmade in accordance with this specification shall be reported tothe manufacturer within a reasonable length of time.12.
34、 Certification12.1 If outside inspection is not required, a manufacturerscertification that the material has been tested in accordancewith and meets the requirements of this specification shall bethe basis of acceptance of the material.12.2 A material test report, certificate of inspection, orsimila
35、r document printed from or used in electronic form froman electronic data interchange (EDI) transmission shall beregarded as having the same validity as a counterpart printed inthe certifiers facility. The content of the EDI transmitteddocument must meet the requirements of the invoked ASTMstandard(
36、s) and conform to any existing EDI agreement be-tween the purchaser and the supplier. Notwithstanding theabsence of a signature, the organization submitting the EDItransmission is responsible for the content of the report.NOTE 2The industry definition as invoked here is: EDI is thecomputer-to-comput
37、er exchange of business information in a standardformat such as ANSI ASC X12.13. Packaging and Package Marking13.1 The type of wire, size of the wire, ASTM specificationA421/A421M, heat number, and name of the manufacturershall be marked on a tag securely attached to each coil of wire.13.2 When spec
38、ified in the purchase order or contract, andfor direct procurement by or direct shipment to the U. S.government, marking for shipment shall be in accordance withFed. Std. No. 123 for civil agencies and MIL-STD-129 formilitary agencies.14. Keywords14.1 cold-drawn wire; low-relaxation wire; prestresse
39、d con-crete; steel wire (tendon); stress-relieved wireSUPPLEMENTARY REQUIREMENTSS1. LOW-RELAXATION WIRE AND RELAXATION TESTINGThe following supplementary requirement shall apply only when specified in the purchase order orcontract.S1.1 ScopeS1.1.1 This supplementary requirement delineates onlythose
40、details which are peculiar to low-relaxation wire, and tothe method of relaxation testing related to single wire tendonshaving properties generally as described in SpecificationA421/A421M.S1.2 Test MethodS1.2.1 Low-relaxation wire shall be tested as prescribed inTest Methods E328.S1.3 Relaxation Pro
41、pertiesS1.3.1 Low-relaxation wire shall meet the mechanical prop-erty requirements of this specification, with the added require-ment that relaxation after 1000 h under the conditions ofSection S1.5 shall not be more than 2.5 % when initially loadedto 70 % of specified minimum tensile strength or no
42、t more than3.5 % when loaded to 80 % of specified minimum tensilestrength of the wire.S1.4 Yield StrengthS1.4.1 Yield strength of low-relaxation wire as described in5.2 shall not be less than 90 % of the specified minimum tensilestrength of the wire.S1.5 Conditions of Relaxation TestS1.5.1 If requir
43、ed, relaxation evidence shall be providedfrom the manufacturers records of tests on similarly dimen-sioned wire of the same grade.S1.5.2 The temperature of the test specimen shall be main-tained at 68 6 3.5F 20 6 2C.S1.5.3 The test specimen shall not be subjected to anyloading prior to the relaxatio
44、n test.S1.5.4 The initial load shall be applied uniformly over aperiod of not less than 3 minutes and not more than 5 minutes,and the gage length shall be maintained constant; load relax-ation readings shall commence 1 minute after application of thetotal load.S1.5.5 Overstressing of the test specim
45、en during the loadingoperation shall not be permitted.S1.5.6 The duration of the test shall be 1000 h or a shorterperiod extrapolated to 1000 h which can be shown by recordsto provide similar relaxation values.S1.5.7 The test gage length shall be at least 60 times thenominal diameter.A421/A421M 103S
46、UMMARY OF CHANGESCommittee A01 has identified the location of selected changes to this standard since the last issue(A421/A421M 05) that may impact the use of this standard. (Approved Nov. 1, 2010.)(1) Re-positioned the units throughout the specification.(2) Corrected errors and made editorial impro
47、vementsthroughout the specification.(3) Revised Section 1 to clarify that the provisions for low-relaxation wire and relaxation testing comprise SupplementaryRequirement S1, and that S1 applies only when specified in thepurchase order.(4) Revised Section 2 to replace Methods E30 with TestMethods, Pr
48、actices, and Terminology A751 and deleted MIL-STD-163.(5) Revised Section 3.(6) Revised 13.2 to overcome the withdrawal of MIL-STD-163.(7) Edited and re-numbered the sections in the SupplementaryRequirements Section.ASTM International takes no position respecting the validity of any patent rights as
49、serted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such 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 either for revision of this stan
