1、Designation: A 421/A 421M 05American Association StateHighway and Transportation Officials StandardAASHTO No.: M 204Standard Specification forUncoated Stress-Relieved Steel Wire for PrestressedConcrete1This standard is issued under the fixed designationA 421/A 421M; the number immediately following
2、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 approved f
3、or use 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
4、used 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 Supplement I describes low relaxation wire and relax-ation testing for that product.1.3 The v
5、alues stated in either inch-pound or SI units are tobe regarded as standard. Within the text, the inch-pound unitsare shown in parentheses. The values stated in each system arenot exact equivalents; therefore, each system shall be usedindependently of the other, without combining values in anyway.2.
6、 Referenced Documents2.1 ASTM Standards:2A 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsE30 Test Methods for Chemical Analysis of Steel, CastIron, Open-Hearth Iron, and Wrought Iron3E 328 Test Methods for Stess Relaxation Tests for Materialsand Structures2.2 Military Stand
7、ards:MIL-STD-129 Marking for Shipment and Storage4MIL-STD-163 Steel Mill Products, Preparation for Ship-ment and Storage42.3 Federal Standard:Fed. Std. No. 123 Marking for Shipments (Civil Agencies)43. Ordering Information3.1 It shall be the responsibility of the purchaser to specifyall requirements
8、 that are necessary for material ordered to thisspecification. Such requirements shall include, but are notlimited to, the following:3.1.1 Quantity (kg lb),3.1.2 Diameter,3.1.3 Type of anchorage (BA or WA),3.1.4 Packaging,3.1.5 ASTM designation and date of issue, and3.1.6 Special requirements, if an
9、y.NOTE 1A typical ordering description is as follows: 10 000 kg of6.35-mm diameter wire, Type BAin approximately 450 kg 1.5-m diametercoils to ASTM A 421/A 421M _(22 000 lb 0.250-in. diameterwire, Type BA in approximately 1000 lb 60-in. diameter coils to ASTMA 421/A 421M_).4. Manufacture4.1 ProcessT
10、he steel shall be made by the basic-oxygen,open-hearth, or electric-furnace 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 after cold drawing by a
11、continuous heat treat-ment to produce the prescribed mechanical properties.5. Physical 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 inTest Methods and Definitions A
12、 370, including Annex A4.5.2 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 breaking strength.1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless St
13、eel and Related Alloys, and is the direct responsibility of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved March 1, 2005. Published March 2005. Originallyapproved in 1958. Last previous edition approved in 2002 as A 421/A 421M 02.2For referenced ASTM standards, visit the ASTM web
14、site, 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.3Withdrawn.4Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelph
15、ia, PA 19111-5094, Attn: NPODS.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.5.2.2 The extension under load shall be measured by anextensometer calibrated with the s
16、mallest division not largerthan 0.0001 mm/mm (0.0001 in./in.) 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 mm/mm (0.001 in./in.) of gage len
17、gth. 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 meet the requirements forstress at 1 % extension prescribed in Table 2.5.3 ElongationThe total elongation under load of
18、all wireshall not be less than 4.0 % when measured in a gage length of250 mm (10 in.). The elongation shall be determined by anextensometer which is 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
19、 gage lengthand the elongation so measured meets the minimum require-ments, no further testing shall be required. If the elongation isless than the minimum requirements, the test shall be consid-ered an invalid test and a retest made.6. Diameter and Permissible Variations6.1 Wire meeting the require
20、ments of this specification isnormally ordered in the diameters shown in Table 1.6.2 The diameter of the wire shall not vary from the nominaldiameter specified by more than 6 0.05 mm (0.002 in.).6.3 The wire shall not be out-of-round by more than 0.05mm (0.002 in.).7. Workmanship and Finish7.1 CastA
21、wire sample having a chord length of 1524 mm(60 in.) shall have an offset at the center of the chord of notmore than 76 mm (3 in.). This is equivalent to a chord of an arcof a circle not less than 7.6 m (25 ft) in diameter.7.2 Type BA WireType BA wire shall be of suitablequality to permit cold formi
22、ng of buttons for anchorage.Splitting shall not be considered a cause for rejection if thebutton anchorage is capable of developing the minimumrequired 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 diamete
23、r of 1219 mm (48 in.). Each coil shallbe of one continuous length.7.5 There shall be no welds or joints in the finished wire.Any welds or joints made during manufacture to promotecontinuity of operations shall be removed.7.6 The wire shall not be oiled or greased. Slight rusting,provided it is not s
24、ufficient to cause pits visible to the nakedeye, shall not be cause for rejection.7.7 Temper colors which result from the stress-relievingoperation are considered normal for the finished appearance ofthis strand.8. Chemical Requirements8.1 Variations in manufacturing processes and equipmentamong wir
25、e manufacturers necessitate the individual selectionof an appropriate chemical composition at the discretion of themanufacturer.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 repr
26、esenting each heat of steel. Samples foranalysis shall be obtained by milling the wire in such a manneras to obtain a sample 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 th
27、e limits shown in 8.2 by more than 0.008 %.8.4 For referee purposes, Methods E30shall 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 2) and tested to determinecompliance with
28、5.1, 5.2, 5.3, 6, and 7.1.NOTE 2The term “lot” means all the coils of wire of the same 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 or waived. If outside inspecti
29、onis required, the manufacturer shall afford the inspector repre-senting the purchaser all reasonable facilities to satisfy him 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 oth
30、erwise agreed upon atthe time of purchase, and shall be so conducted as not tointerfere unnecessarily with the operation of the works.11. Rejection11.1 Unless otherwise specified, any rejection based on testsmade in accordance with this specification shall be reported tothe manufacturer within a rea
31、sonable length of time.TABLE 1 Tensile Strength RequirementsNominal Diameter, mm(in.)Tensile Strength, min, MPa (psi)Type BA Type WA4.88 (0.192)A1725 (250 000)4.98 (0.196) 1655 (240 000) 1725 (250 000)6.35 (0.250) 1655 (240 000) 1655 (240 000)7.01 (0.276) 1620 (235 000) 1620 (235 000)AThis size is n
32、ot commonly furnished in Type BA wire.TABLE 2 Yield Strength RequirementsNominalDiameter,mm (in.)Initial Stress,MPa (psi)Minimum Stress at 1 %Extension, MPa (psi)Type BA Type WA4.88 (0.192) 200 (29 000)A1465 (212 500)4.98 (0.196) 200 (29 000) 1407 (204 000) 1465 (212 500)6.35 (0.250) 200 (29 000) 14
33、07 (204 000) 1407 (204 000)7.01 (0.276) 200 (29 000) 1377 (199 750) 1377 (199 750)AThis size is not commonly furnished in Type BA wire.A 421/A 421M 05212. Certification12.1 If outside inspection is waived, a manufacturers cer-tification that the material has been tested in accordance withand meets t
34、he requirements of this specification shall be thebasis of acceptance of the material.12.2 A material test report, certificate of inspection, orsimilar document printed from or used in electronic form froman electronic data interchange (EDI) transmission shall beregarded as having the same validity
35、as a counterpart printed inthe certifiers facility. The content of the EDI transmitteddocument must meet the requirements of the invoked ASTMstandard(s) and conform to any existing EDI agreement be-tween the purchaser and the supplier. Notwithstanding theabsence of a signature, the organization subm
36、itting the EDItransmission is responsible for the content of the report.NOTE 3The industry definition as invoked here is: EDI is thecomputer-to-computer exchange of business information in a standardformat such as ANSI ASC X12.13. Packaging and Marking13.1 The size of the wire, ASTM specification nu
37、mber, heatnumber, and name or mark of the manufacturer shall be markedon a tag securely attached to each bundle of wire.13.2 For Government Procurement Only When specifiedin the contract or order, and for direct procurement by or directshipment to the government, material shall be preserved,packaged
38、, and packed in accordance with the requirements ofMIL-STD-163. The applicable levels shall be as specified inthe contract. Marking for shipment of such material shall be inaccordance with Fed. Std. No. 123 for civil agencies andMIL-STD-129 for military agencies.14. Keywords14.1 cold-drawn wire; pre
39、stressed concrete; steel wire (ten-don); stress-relieved wireSUPPLEMENTARY REQUIREMENTSI. LOW-RELAXATION WIRES1. ScopeS1.1 This supplement delineates only those details whichare peculiar to low-relaxation wire, and to the method ofrelaxation testing related to single wire tendons having prop-erties
40、generally as described in Specification A 421.S2. Referenced DocumentS2.1 ASTM Standard:E 328 Methods for Stress-Relaxation Tests for Materials andStructuresS3. Test MethodS3.1 Low-relaxation strand shall be tested as prescribed inMethods E 328.S4. Relaxation PropertiesS4.1 Low-relaxation wire shall
41、 meet the physical require-ments of this specification, with the added requirement thatrelaxation after 1000 h under the conditions of Section S5 shallnot be more than 2.5 % when initially loaded to 70 % ofspecific minimum tensile strength or not more than 312 %when loaded to 80 % of specified minim
42、um tensile strength ofthe wire.S5. Yield StrengthS5.1 Yield strength of low-relaxation wire as described in5.2 shall not be less than 90 % of the specified minimum tensilestrength of the wire.S6. Conditions of Relaxation TestS6.1 If required, relaxation evidence shall be provided fromthe manufacture
43、rs records of tests on similarly dimensionedwire of the same grade.S6.2 The temperature of the test specimen shall be main-tained at 20 6 2C (68 6 3.5F).S6.3 The test specimen shall not be subjected to any loadingprior to the relaxation test.S6.4 The initial load shall be applied uniformly over aper
44、iod of not less than 3 min and not more than 5 min, and thegage length shall be maintained constant; load relaxationreadings shall commence 1 min after application of the totalload.S6.5 Overstressing of the test specimen during the loadingoperation shall not be permitted.S6.6 The duration of the tes
45、t shall be 1000 h or a shortercomputed period extrapolated to 1000 h which can be shownby records to provide similar relaxation values.S6.7 The test gage length shall be at least 60 times thenominal diameter.A 421/A 421M 053SUMMARY OF CHANGESCommittee A01 has identified the location of the following
46、 changes to this standard since the last issue (A421/A 421M 02) that may impact the use of this standard.(1)Sections 3.1, 5.3, 8.3, and S6.5 were revised.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard.
47、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 ev
48、ery five years andif not revised, either reapproved or withdrawn. Your comments are invited either 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 tech
49、nical committee, which you may attend. If you feel that your comments have not received a fair hearing 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 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 w
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