1、Designation: A 910/A 910M 05Standard Specification forUncoated, Weldless, 2- and 3-Wire Steel Strand forPrestressed Concrete1This standard is issued under the fixed designationA 910/A 910M; the number immediately following the designation indicates the yearof original adoption or, in the case of rev
2、ision, 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.1. Scope*1.1 This specification covers two types and two grades of 2-and 3-wire, uncoated steel strand for use
3、 in pretensioned andposttensioned prestressed concrete construction. The two typesof strand are low-relaxation and stress-relieved (normal-relaxation). Low-relaxation shall be regarded as the standardtype. Stress-relieved (normal-relaxation) strand will not befurnished unless specifically ordered, o
4、r by arrangement be-tween purchaser and supplier. The two grades are 1725 (250)and 1860 (270). Grades 250 and 270 have minimum tensilestrengths of 1725 MPa (250 ksi) and 1860 MPa (270 ksi)respectively, based on the nominal area of the strand.1.2 The values stated in either inch-pound units or SI uni
5、tsare to be regarded as the standard. Within the text, theinch-pound units are shown in parentheses. The values statedin each system are not exact equivalents; therefore, eachsystem must be used independently of the other. Combiningvalues from the two systems may result in nonconformancewith the spe
6、cification.2. Referenced Documents2.1 ASTM Standards:2A 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsE 328 Test Methods for Stress Relaxation Tests for Materi-als and Structures2.2 U.S. Military Standards:MIL-STD-129 Marking for Shipment and Storage3MIL-STD-163 Steel Mill
7、Products Preparation for Ship-ment and Storage32.3 Federal Standard:Fed. Std. No. 123 Marking for Shipments (Civil Agencies)33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 strand, nall strands shall be comprised of either twowires or three wires helically wound around each ot
8、her; theyshall have a uniform pitch of not less than 12 nor more than 16times the nominal diameter of the strand.3.1.2 DiscussionThe direction of lay may be either rightor left hand; however, strands of different lays shall not bespliced together.4. Ordering Information4.1 It shall be the responsibi
9、lity of the purchaser to specifyall requirements that are necessary for material ordered to thisspecification. Such requirements shall include, but are notlimited to, the following:4.1.1 Quantity (meters feet),4.1.2 Diameter of strand (Section 7),4.1.3 Number of wires (2 or 3),4.1.4 Grade of strand
10、(see 1.1 and Table 1 and Table 2),4.1.5 Type of strand (see 1.1 and Table 2),4.1.6 Packaging (Section 14),4.1.7 ASTM designation and year of issue, and4.1.8 Special requirements, if any.NOTE 1A typical ordering description is as follows: 100 000 m(325 000 ft) of 6.2 mm (0.244 in.) diameter, three wi
11、re, Grade 1860 MPa(270 ksi), low-relaxation strand in 10 000 m (32 500 ft) reelless packsconforming to ASTM A 910/A 910MXX.5. Materials and Manufacture5.1 Base MetalThe base metal shall be carbon steel ofsuch quality that when drawn to wire, fabricated into strandand then thermally treated, it shall
12、 have the properties andcharacteristics prescribed in this specification.5.2 WireThe wire from which the strand is to be fabri-cated shall be round and have a dry-drawn finish.NOTE 2This product is a composite of two or three wires and isproduced to mechanical properties only, of which the chemical
13、composi-tion of all wires or any individual wire is not pertinent to this application,and heat identity is not necessarily maintained. It is possible that wire1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainless Steel, and Related Alloys and is the direct responsibi
14、lity of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved March 1, 2005. Published March 2005. Originallyapproved in 1992. Last previous edition approved in 1999 as A 910/A 910M 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service
15、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, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.1*A Summary of Changes section a
16、ppears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.from more than one heat may be used in the manufacture of a reel or pack.Traceability is based on pack identity as maintained and reported by themanufa
17、cturer.5.3 TreatmentAfter stranding, low-relaxation strand shallbe subjected to a continuous thermo-mechanical treatment toproduce the prescribed mechanical properties. For stress-relieved (normal-relaxation) strand, only thermal treatment isnecessary. Temper colors that result from the stress-relie
18、vingoperation are considered normal for the finished appearance ofthis strand.6. Mechanical Properties6.1 Methods of testing for mechanical properties are inAnnex A7 of Test Methods and Definitions A 370. Low-relaxation strand shall also be tested as prescribed in MethodsE 328.6.2 Breaking StrengthT
19、he breaking strength of the fin-ished strand shall conform to the requirements prescribed inTable 1.6.3 Yield StrengthYield strength in kN (lbs) shall bemeasured at 1 % extension under load. The minimum yieldstrength shall be 90 % for low-relaxation strand and 85 % forstress-relieved (normal relaxat
20、ion) strand of the breakingstrength listed inTable 1. Initial loads for the test and minimumyield strengths are listed in Table 2.6.4 ElongationThe total elongation under load shall notbe less than 3.5 %. It shall be permissable to determine the totalelongation value by adding to the 1.0 % yield ext
21、ension thepercent extension or movement between the jaws gripping thestrand after yield determination. The percent is calculated onthe new base length of jaw-to-jaw distance.TABLE 1 Breaking Strength RequirementsDescription and Diameter of StrandBreaking Strength ofStrandSteel Area ofStrandWeight of
22、Strandin. mmDescriptionNominalDiameterDescriptionNominalDiameterlbf kN in.2mm2lbs/1000 ft kg/1000 mGRADE 250 (1725 MPa)2 3 0.114 0.228 2 3 2.90 5.8 5000 22.2 0.020 13.2 69.9 104.03 3 0.089 0.189 3 3 2.25 4.8 4750 21.1 0.019 12.0 63.3 94.23 3 0.095 0.205 3 3 2.40 5.2 5250 23.4 0.021 13.6 71.9 107.03
23、3 0.114 0.244 3 3 2.90 6.2 7750 34.5 0.031 19.8 104.0 155.03 3 0.118 0.256 3 3 3.00 6.5 8250 36.7 0.033 21.3 112.0 167.03 3 0.138 0.295 3 3 3.50 7.5 11 250 50.0 0.045 29.0 153.0 228.03 3 0.158 0.340 3 3 4.00 8.6 14 500 64.5 0.058 37.4 200.6 298.4GRADE 270 (1860 MPa)2 3 0.114 0.228 2 3 2.90 5.8 5400
24、24.0 0.020 13.2 69.9 104.03 3 0.089 0.189 3 3 2.25 4.8 5130 22.8 0.019 12.0 63.3 94.23 3 0.095 0.205 3 3 2.40 5.2 5670 25.2 0.021 13.6 71.9 107.03 3 0.114 0.244 3 3 2.90 6.2 8370 37.2 0.031 19.8 104.0 155.03 3 0.118 0.256 3 3 3.00 6.5 8910 39.6 0.033 21.3 112.0 167.03 3 0.138 0.295 3 3 3.50 7.5 12 1
25、50 54.0 0.045 29.0 153.0 228.03 3 0.158 0.340 3 3 4.00 8.6 15 660 69.7 0.058 37.4 200.6 298.4TABLE 2 Yield Strength RequirementsDescription and Diameter of StrandInitial LoadMinimum Load at 1 % Extensionin. mmStress-Relieved(Normal Relaxation)Low RelaxationDescriptionNominalDiameterDescriptionNomina
26、lDiameterlbf kN lbf kN lbf kNGRADE 250 (1725 MPa)2 3 0.114 0.228 2 3 2.90 5.8 500 2.2 4250 18.9 4500 20.03 3 0.089 0.189 3 3 2.25 4.8 475 2.1 4038 18.0 4275 19.03 3 0.095 0.205 3 3 2.40 5.2 525 2.3 4463 20.0 4725 21.03 3 0.114 0.244 3 3 2.90 6.2 775 3.5 6588 29.3 6975 31.03 3 0.118 0.256 3 3 3.00 6.
27、5 825 3.7 7013 32.2 7425 33.03 3 0.138 0.295 3 3 3.50 7.5 1250 5.0 9563 42.5 10 125 45.03 3 0.158 0.340 3 3 4.00 8.5 1450 6.5 12 325 54.8 13 050 11.7GRADE 270 (1860 MPa)2 3 0.114 0.228 2 3 2.90 5.8 540 2.4 4590 20.4 4860 21.63 3 0.089 0.189 3 3 2.25 4.8 513 2.3 4360 19.4 4617 20.53 3 0.095 0.205 3 3
28、 2.40 5.2 567 2.5 4820 21.4 5103 22.73 3 0.114 0.244 3 3 2.90 6.2 837 3.7 7115 31.6 7533 33.53 3 0.118 0.256 3 3 3.00 6.5 891 4.0 7574 33.7 8019 36.03 3 0.138 0.295 3 3 3.50 7.5 125 5.4 10 328 45.9 10 125 45.03 3 0.158 0.340 3 3 4.00 8.6 566 7.0 13 311 59.2 14 094 62.7A 910/A 910M 0526.5 Relaxation
29、PropertiesLow-relaxation strand shallhave relaxation losses of not more than 2.5 % when initiallyloaded to 70 % of specified minimum breaking strength or notmore than 3.5 % when loaded to 80 % of specified minimumbreaking strength of the strand after 1000 h tested underconditions listed in 6.5.1 thr
30、ough 6.5.7.6.5.1 If required, relaxation evidence shall be provided fromthe manufacturers records of tests on similarly dimensionedstrand of the same grade.6.5.2 The temperature of the test specimen shall be main-tained at 20 6 2C (68 6 3.5F).6.5.3 The test specimen shall not be subjected to loading
31、prior to the relaxation test.6.5.4 The initial load shall be applied uniformly over aperiod 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.6.5.5 Overstressing of the test
32、specimen during the loadingoperation shall not be permitted.6.5.6 The duration of the test shall be 1000 h or a shortercomputed period extrapolated to 1000 h that can be shown byrecords to provide similar relaxation values.6.5.7 The test gage length shall be at least 60 times thenominal diameter of
33、the strand. If this gage length exceeds thecapacity of the extensometer or the testing machine, then it ispermitted to substitute a minimum gage length of 40 times thenominal diameter of the strand.7. Dimensions and Permissible Variations7.1 The size of the finished strand shall be expressed as thed
34、iameter of the strand as decimal fraction of an inch.7.2 Variations in individual wire diameters shall not because for rejection provided that the other requirements of thisspecification are met.7.3 Specially-Dimensioned Strand:7.3.1 It shall be permitted to furnish, under this specifica-tion, stran
35、ds with nominal diameters that are different thanthose listed in Table 1 and Table 2. The breaking strength shallbe defined, and the yield strength, as defined in 6.3, shall not beless than 90 % and 85 % of the specified minimum breakingstrength for low-relaxation and stress-relieved (normal-relaxat
36、ion) strand, respectively. All other requirements shallapply.7.4 Permissible Variations in Diameter:7.4.1 All Grade 1725 (250) strand shall conform to a sizetolerance of 60.41 mm (60.016 in.) from the diametermeasured across the crowns of the wires (2-wire strand only).For 3-wire strand, the diamete
37、r is that diameter of a circlewhich can be tangentially circumscribed around the 3 wires.This can be confirmed by comparing the individual wirediameters in the strand to those listed in Table 1 and Table 2.7.4.2 All Grade 1860 (270) strand shall conform to a sizetolerance of +0.66 mm, 0.15 mm (+0.02
38、6 in., 0.006 in.)from the nominal diameter measured across the crowns of thewires (2-wire strand only). For 3-wire strand, the nominaldiameter is that diameter of a circle which can be tangentiallycircumscribed around the 3 wires. This can be confirmed bycomparing the individual wire diameters in th
39、e strand to thoselisted in Table 1 and Table 2.8. Workmanship, Finish and Appearance8.1 Joints:8.1.1 There shall be no strand splices in any length of thecompleted strand.8.1.2 There shall be no wire welds made in the finishedstrands. During manufacturing of individual wires for strand-ing, welding
40、is permitted only prior to or at the size of the lastthermal treatment (for example, patenting or control cooling).There shall be no welds in the wire after it has been drawnthrough the first die in wire drawing.8.2 The finished strand shall be uniform in diameter andshall be free of imperfections n
41、ot consistent with good com-mercial stranding practice.8.3 When the strand is cut without seizings, the wire shallnot fly out of position. If any wire flies out of position and canbe replaced by hand, the strand will be considered satisfactory.8.4 The strand shall not be oiled or greased. Slight rus
42、ting,provided it is not sufficient to cause pits visible to the unaidedeye, shall not be cause for rejection.9. Sampling9.1 Test specimens cut from either end of the strand packageare permitted.10. Number of Tests10.1 One specimen for test shall be taken from each 18-Mg(20-ton) production lot of fin
43、ished strand, and tested forbreaking strength, yield strength, and elongation.11. Inspection11.1 If outside inspection is required, the manufacturer shallafford the inspector representing the purchaser all reasonablefacilities to satisfy that the material is being furnished inaccordance with this sp
44、ecification. All tests and inspectionsshall be made at the place of manufacture prior to shipment,unless otherwise agreed upon at the time of purchase, and shallbe so conducted as not to interfere unnecessarily with theoperation of the works.NOTE 3The purchaser should state at the time of order whet
45、heroutside inspection is required or waived.12. Rejection and Retesting12.1 Failure of any test specimen to comply with therequirements of the specification shall constitute grounds forrejection of the lot represented by the specimen.12.2 If any specimen being tested for breaking strength,yield stre
46、ngth, elongation, or stress-relaxation results in valuesoutside the specified limits, two additional tests shall be madeon specimens of strand from the same reel. If failure occurs ineither of these tests, the strand shall be rejected.12.3 It shall be permissable to resubmit the lot for inspec-tion
47、by testing a specimen from each reel or pack and sortingout nonconforming material.A 910/A 910M 05313. Certification13.1 If outside inspection is waived, a manufacturers cer-tification that the material has been tested in accordance withand meets the requirements of this specification shall be theba
48、sis of acceptance of the material. The certification shallinclude the specification number, year-date of issue, andrevision letter, if any.13.2 The manufacturer shall, when requested in the order,furnish a representative load-elongation curve for each size andgrade of strand shipped.13.3 When the mo
49、dulus of elasticity of a 2- or 3-wire strandis provided, the cross-sectional area used to compute themodulus shall also be provided. The area provided in thecertification shall be the area used to calculate the modulus ofelasticity.13.4 A material test report, certification or inspection, orsimilar 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 requireme
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