1、Designation: A 416/A 416M 06Standard Specification forSteel Strand, Uncoated Seven-Wire for PrestressedConcrete1This standard is issued under the fixed designationA 416/A 416M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the ye
2、ar 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 for use by agencies of the Department of Defense.1. Scope*1.1 This specification covers two
3、 types and two grades ofseven-wire, uncoated steel strand for use in pretensioned andpost-tensioned prestressed concrete construction. The twotypes of strand are low-relaxation and stress-relieved (normal-relaxation). Low-relaxation strand shall be regarded as thestandard type. Stress-relieved (norm
4、al-relaxation) strand willnot be furnished unless specifically ordered, or by arrangementbetween purchaser and supplier. Grade 1725 250 and Grade1860 270 have minimum ultimate strengths of 1725 MPa250 ksi and 1860 MPa 270 ksi, respectively, based on thenominal area of the strand.1.2 The values state
5、d in either inch-pound units or SI unitsare to be regarded as standard. Within the text, the inch-poundunits are shown in brackets. The values stated in each systemare not exact equivalents; therefore, each system must be usedindependently of the other. Combining values from the twosystems may resul
6、t in nonconformance with the specification.1.3 The supplementary requirements in S1 shall be specifiedfor 15.2-mm 0.600-in. diameter uncoated seven-wire steelstrand if needed for applications in prestressed ground anchors.2. Referenced Documents2.1 ASTM Standards:2A 370 Test Methods and Definitions
7、for Mechanical Testingof Steel ProductsA 981 Test Method for Evaluating Bond Strength for 15.2mm (0.6 in.) Diameter Prestressing Steel Strand, Grade270, Uncoated, Used in Prestressed Ground AnchorsE 328 Test Methods for Stress Relaxation for Materials andStructures2.2 U.S. Military Standards:MIL-STD
8、-129 Marking for Shipment and Storage3MIL-STD-163 Steel Mill Products Preparation for Ship-ment and Storage32.3 U.S. Federal Standard:Fed. Std. No. 123 Marking for Shipments (CivilAgencies)33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 strand, na group of wires having a cent
9、er wireenclosed tightly by six helically placed outer wires withuniform pitch of not less than 12 and not more than 16 timesthe nominal diameter of the strand.3.1.1.1 DiscussionThe direction of lay may be eitherright- or left-hand, however, strands of different lays should notbe spliced together.4.
10、Ordering Information4.1 Orders for seven-wire low-relaxation or stress-relieved(normal-relaxation) strand under this specification should in-clude the following information:4.1.1 Quantity (meters feet),4.1.2 Diameter of strand,4.1.3 Grade of strand,4.1.4 Type of strand,4.1.5 Packaging,4.1.6 ASTM des
11、ignation and year of issue, and4.1.7 Special requirements, if any.NOTE 1Atypical ordering description is as follows: 25 600 m 84 000ft, 13 mm 0.5 in., Grade 1860 270 low-relaxation strand, in 3600-m12 000-ft reelless packs to ASTM A 416/A 416M _.5. Materials and Manufacture5.1 Base MetalThe base met
12、al shall be carbon steel ofsuch quality that when drawn to wire, fabricated into strand,and then thermally treated, shall 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.1Th
13、is 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 April 1, 2006. Published April 2006. Originallyapproved in 1957. Last previous edition a
14、pproved in 2005 as A 416 05.2For 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 standards Document Summary page onthe ASTM website.3Available from Standardization D
15、ocuments Order Desk, Bldg. 4, Section D,700 Robbins Ave., Philadelphia, PA 19111-5094.1*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.NOTE 2This product is a composite
16、 of seven wires and is produced tomechanical properties only. The chemical composition of all wires or anyindividual wire is not pertinent to this application, and heat identity is notnecessarily maintained. It is possible that wire from more than one heatmay be used in the manufacture of a reel or
17、pack. Traceability is based onpack identity as maintained and reported by the manufacturer.5.3 TreatmentAfter stranding, low-relaxation strand shallbe subjected to a continuous thermal-mechanical treatment toproduce the prescribed mechanical properties. For stress-relieved (normal-relaxation) strand
18、, only thermal treatment isnecessary. Temper colors which result from the stress-relievingoperation are considered normal for the finished appearance ofthis strand.6. Mechanical Properties6.1 Methods of testing for mechanical properties are de-scribed in Annex A7 of Test Methods and Definitions A 37
19、0.Low-relaxation strand shall also be tested as prescribed inMethods E 328.6.2 Breaking StrengthThe breaking strength of the fin-ished strand shall conform to the requirements prescribed inTable 1.6.3 Yield StrengthYield strength in kN pounds shall bemeasured at 1 % extension under load. The minimum
20、 yieldstrength shall be 90 % for low-relaxation strand and 85 % forstress-relieved (normal-relaxation) strand of the breakingstrength listed in Table 1. Initial loads for the test and minimumyield strengths are listed in Table 2.6.3.1 The extension under load shall be measured by anextensometer cali
21、brated with the smallest division not largerthan 0.0001 mm/mm 0.0001 in./in. of gage length.6.4 ElongationThe total elongation under load shall notbe less than 3.5 % using a gage length of not less than 600 mm24 in. It shall be permissable to determine the total elonga-tion value by adding, to the 1
22、.0 % yield extension, the percentextension or movement between the jaws gripping the strandafter yield determination. The percent is calculated on the newbase length of jaw-to-jaw distance.6.5 Relaxation PropertiesLow-relaxation strand shallhave relaxation losses of not more than 2.5 % when initiall
23、yloaded 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 under theconditions listed in 6.5.1 through 6.5.7.6.5.1 If required, relaxation evidence shall be provided fromthe manufacturers re
24、cords 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 loadingprior to the relaxation test.6.5.4 The initial load shall be applied uniformly over aperiod of
25、 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 Over-stressing of the test specimen during the loadingoperation shall not be permitted.6.5.6 The duration of the test s
26、hall be 1000 h or a shorterperiod of at least 200 h, provided it can be shown by recordsthat an extrapolation of the shorter period test results to 1000h will provide similar relaxation values as the full 1000 h test.6.5.7 The test gage length shall be at least 60 times thenominal diameter. If this
27、gage length exceeds the capacity ofthe extensometer or testing machine, then it shall be permittedto substitute a gage length of 40 times the nomimal stranddiameter.7. Dimensions and Permissible Variations7.1 The size of the finished strand shall be expressed as thenominal diameter of the strand in
28、millimetres inches.7.2 The diameter of the center wire of any strand shall belarger than the diameter of any outer wire in accordance withTable 3.7.3 Permissible Variations in Diameter:7.3.1 All Grade 1725 250 strand shall conform to a sizetolerance of 60.40 mm 60.016 in. from the nominal diam-eter
29、measured across the crowns of the wires.7.3.2 All Grade 1860 270 strand shall conform to a sizetolerance of +0.65, 0.15 mm +0.026, 0.006 in. from thenominal diameter measured across the crowns of the wire.TABLE 1 Breaking Strength RequirementsStrand Designation No. Diameter of Strand, mmin.Minimum B
30、reakingStrength of Strand, kN lbfSteel Area of Strand,mm2in.2Weight of Strand kg/1000m lb/1000 ftGrade 1725 2506 6.4 0.250 40.0 9 000 23.2 0.036 182 1228 7.9 0.313 64.5 14 500 37.4 0.058 294 1979 9.5 0.375 89.0 20 000 51.6 0.080 405 27211 11.1 0.438 120.1 27 000 69.7 0.108 548 36713 12.7 0.500 160.1
31、 36 000 92.9 0.144 730 49015 15.2 0.600 240.2 54 000 139.4 0.216 1094 737Grade 1860 2709 9.53 0.375 102.3 23 000 54.8 0.085 432 29011 11.11 0.438 137.9 31 000 74.2 0.115 582 39013 12.70 0.500 183.7 41 300 98.7 0.153 775 52013a 13.20 0.520 200.2 45 000 107.7 .0167 844 56814 14.29 0.563 230.0 51 700 1
32、23.9 .0192 970 65115 15.24 0.600 260.7 58 600 140.0 0.217 1102 74018 17.78 0.700 353.2 79 400 189.7 0.294 1487 1000A 416/A 416M 0627.3.3 Variation in cross-sectional area and in unit stressresulting therefrom shall not be cause for rejection providedthat the diameter differences of the individual wi
33、res and thediameters of the strand are within the tolerances specified.7.4 It shall be permitted to furnish, under this specification,specially dimensioned low-relaxation and stress-relieved(normal-relaxation) strands with nominal diameters up to 19mm 0.750 in. The breaking strength shall be defined
34、, and theyield strength, as defined in 6.3, shall not be less than 90 % and85 % of the specified minimum breaking strength for low-relaxation and stress-relieved (normal relaxation) strands, re-spectively. All other requirements shall apply.8. Workmanship, Finish, and Appearance8.1 Joints:8.1.1 Ther
35、e shall be no strand joints or strand splices in anylength of the completed strand unless specifically permitted bythe purchaser.8.1.2 During the process of manufacture of individual wiresfor stranding, welding shall be permitted only prior to or at thesize of the last thermal treatment, for example
36、, patenting orcontrolled cooling. There shall be no welds in the wire after ithas been drawn through the first die in the wire drawing exceptas provided in 8.1.3.8.1.3 During fabrication of the strand, butt-welded joints arepermitted in the individual wires, provided there shall not bemore than one
37、such joint in any 45-m 150-ft section of thecompleted strand.8.1.4 When specifically ordered as “Weldless,” a productfree of welds shall be furnished. When “Weldless” is specified,the strand is produced as one continuous length with no weldsas allowed by 8.1.3.8.2 The finished strand shall be unifor
38、m in diameter andshall be free of imperfections not consistent with good com-mercial strand practices.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 shall be considered satisfactory.8.4 The
39、strand shall not be oiled or greased. Slight rusting,provided it is not sufficient to cause pits visible to the unaidedeye, shall not be cause for rejection.TABLE 2 Yield Strength RequirementsStrandDesignationNo.Nominal Diameterof Strandmm in.Initial Load,kN lbfMinimum Load at 1 % Extension,kN lbfLo
40、w-Relaxation Normal-RelaxationGrade 1725 2506 6.4 0.250 4.0 900 36.0 8 100 34.0 7 6508 7.9 0.313 6.5 1 450 58.1 13 050 54.7 12 3009 9.5 0.375 8.9 2 000 80.1 18 000 75.6 17 00011 11.1 0.438 12.0 2 700 108.1 24 300 102.3 23 00013 12.7 0.500 16.0 3 600 144.1 32 400 136.2 30 60015 15.2 0.600 24.0 5 400
41、216.2 48 600 204.2 45 900Grade 1860 2709 9.53 0.375 10.2 2 300 92.1 20 700 87.0 19 55011 11.11 0.438 13.8 3 100 124.1 27 900 117.2 26 35013 12.70 0.500 18.4 4 130 165.3 37 170 156.1 35 10013a 13.20 0.520 20.0 4 500 180.1 40 500 170.1 38 25014 14.29 0.563 23.0 5 170 207.0 46 530 195.5 43 95015 15.24
42、0.600 26.1 5 860 234.6 52 740 221.5 49 80018 17.78 0.700 35.3 7 940 318.0 71 500 300.2 67 500TABLE 3 Diameter Relation Between Center and Outer WiresStrandDesignation No.Nominal Diameter of Strands,mm in.Minimum Difference BetweenCenter Wire Diameter and Diameterof Any Outer Wire, mm in.Grade 1725 2
43、506 6.4 0.250 0.025 0.0018 7.9 0.313 0.038 0.00159 9.5 0.375 0.051 0.00211 11.1 0.438 0.064 0.002513 12.7 0.500 0.076 0.00315 15.2 0.600 0.102 0.004Grade 1860 2709 9.53 0.375 0.0508 0.00211 11.11 0.438 0.0635 0.002513 12.70 0.500 0.0762 0.00313a 13.20 0.520 0.0762 0.00314 14.29 0.563 0.0889 0.003515
44、 15.24 0.600 0.1016 0.00418 17.78 0.700 0.1143 0.0045A 416/A 416M 063NOTE 3Guidance for evaluating the degree of rusting on prestressedconcrete strand is presented in Sason.49. Sampling9.1 Test specimens cut from either end of the strand packageare permitted.Any specimen found to contain a wire join
45、t shallbe discarded and a new specimen obtained.10. Number of Tests10.1 One specimen for test shall be taken from each 18-Mg20-ton production lot of finished strand, and tested forbreaking strength, yield strength, and elongation.11. Inspection11.1 If outside inspection is required, the manufacturer
46、 shallafford the inspector representing the purchaser all reasonablefacilities to satisfy that the material is being furnished inaccordance with this specification. All tests and inspectionsshall be made at the place of manufacture prior to shipment,unless otherwise agreed upon at the time of purcha
47、se, and shallbe so conducted as not to interfere unnecessarily with theoperation of the works.NOTE 4The purchaser should state, at the time of order, whetheroutside inspection is required or waived.12. Rejection12.1 Failure of any test specimen to comply with therequirements of the specification sha
48、ll constitute grounds forrejection of the lot represented by the specimen.12.2 The lot shall be resubmitted for inspection by testing aspecimen from each reel or pack and sorting out non-conforming material.12.3 In case there is a reasonable doubt in the initial testingas to the ability of the strand to meet any requirement of thisspecification, two additional tests shall be made on a specimenof strand from the same reel or pack, and if failure occurs ineither of these tests, the strand shall be rejected.13. Certificat
