1、Designation: A416/A416M 17A416/A416M 17aStandard Specification forLow-Relaxation, Seven-Wire Steel Strand for PrestressedConcrete1This standard is issued under the fixed designation A416/A416M; the number immediately following the designation indicates the yearof original adoption or, in the case of
2、 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 use by agencies of the U.S. Department of Defense.1. Scope*1.1 This spe
3、cification covers two grades of low-relaxation, seven-wire steel strand for use in prestressed concrete construction.Grade 250 1725 and Grade 270 1860 have minimum tensile strengths of 250 ksi 1725 MPa and 270 ksi 1860 MPa,respectively, based on the nominal area of the strand.1.2 Asupplementary requ
4、irement (S1) is provided for use where bond strength testing of 0.600-in. 15.24-mm diameter Grade270 1860 strand for applications in prestressed ground anchors is required by the purchaser. The supplementary requirementapplies only when specified in the purchase order.1.3 The text of this specificat
5、ion contains notes or footnotes, or both, that provide explanatory material. Such notes andfootnotes do not contain any mandatory information.1.4 This specification is applicable for orders in either inch-pound units (as Specification A416) or in SI units (as SpecificationA416M).1.5 The values state
6、d in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI unitsare shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be usedindependently of the other. Combining values from the two systems
7、 may result in non-conformance with the specification.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby
8、 the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A981/A981M Test Method for Evaluating Bond Strength for 0.600-in. 15.24-mm Diameter Steel Prestressing Strand, Grade270 1860, Uncoated, Used in Prestressed Ground AnchorsA1061/A1061M
9、Test Methods for Testing Multi-Wire Steel Prestressing Strand2.2 U.S. Military Standard:3MIL-STD-129 Marking for Shipment and Storage2.3 U.S. Federal Standard:3Fed. Std. No. 123 Marking for Shipments (Civil Agencies)3. Terminology3.1 Definition of Term Specific to This Specification:3.1.1 strand, na
10、 group of wires having a center wire enclosed tightly by six helically placed outer wires with uniform pitchof not less than 12 and not more than 16 times the nominal diameter of the strand.1 This specification is under the jurisdiction ofASTM Committee A01 on Steel, Stainless Steel and RelatedAlloy
11、s and is the direct responsibility of Subcommittee A01.05on Steel Reinforcement.Current edition approved May 1, 2017Dec. 1, 2017. Published May 2017December 2017. Originally approved in 1957. Last previous edition approved in 20162017 asA416/A416M 16.A416/A416M 17. DOI: 10.1520/A0416_A0416M-17.10.15
12、20/A0416_A0416M-17A.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from DLA Document Services, B
13、uilding 4/D, 700 Robbins Ave., Philadelphia, PA 19111-5094, http:/quicksearch.dla.mil.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to
14、adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright A
15、STM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.1.1 DiscussionThe direction of lay is either right-handed or left-handed.4. Ordering Information4.1 Orders for low-relaxation seven-wire steel strand under this specification shall contain the
16、following information:4.1.1 Quantity (feet metres),4.1.2 Nominal diameter of strand (inches millimetres),4.1.3 Grade of strand, and4.1.4 ASTM designation A416 A416M and year of issue.4.2 It The purchaser shall be the responsibility of the purchaser to specify all requirements that are necessary for
17、materialordered under this specification. Such requirements to be considered include, but are have the option to specify additionalrequirements, including but not limited to, the following:4.1.1 Quantity (feet metres),4.2.1 Nominal diameter of strand, Relaxation evidence for similarly dimensioned st
18、rand of the same grade (6.5.1),4.1.3 Grade of strand,4.2.2 Specially dimensioned strand (7.4), ifdesired,4.2.3 Weldless, if desired Weldless strand (8.1),4.2.4 Outside inspection, if requiredRequirements for outside inspection (11.1),4.2.5 Load-elongation curve, if desired curve (13.2),4.2.6 Packagi
19、ng (and package marking (Section 14.114),4.2.7 Supplementary Requirement S1, if desired, and4.2.8 ASTM designationOther special A416 requirements, ifA416M and year of issue. any.5. Materials and Manufacture5.1 Base MetalThe base metal shall be carbon steel of such quality that when drawn to wire, fa
20、bricated into strand, and thenthermally treated, shall have the properties and characteristics prescribed in this specification.5.2 WireThe wire from which the strand is to be fabricated shall be round and have a dry-drawn finish.NOTE 1This product is a composite of seven wires and is produced only
21、to meet the prescribed mechanical properties. The chemical compositionof all wires or any individual wire is not pertinent to this application, and heat identity is not necessarily maintained. It is possible that wire from morethan one heat may be used in the manufacture of a reel or reelless pack.
22、Traceability is based on identity of reels or reelless packs as maintained andreported by the manufacturer.5.3 TreatmentAfter stranding, strand shall be subjected to a continuous thermal-mechanical treatment to produce theprescribed mechanical properties. Temper colors which result from the thermal-
23、mechanical treatment are considered normal for thefinished appearance of this strand.6. Mechanical Property Requirements6.1 Tests for mechanical properties shall be conducted in accordance with Test Methods A1061/A1061M.6.2 Breaking StrengthThe breaking strength of the finished strand shall conform
24、to the requirements prescribed in Table 1.TABLE 1 Breaking Strength RequirementsNominal Diameterof Strand, in. mmMinimum BreakingStrength ofStrand, lbf kNSteel Area ofStrand, in.2 mm2Weight Mass ofStrand lb/1000 ftkg/1000 mGrade 250 17250.250 6.4 9 000 40.0 0.036 23 122 1820.313 7.9 14 500 64.5 0.05
25、8 37 197 2940.375 9.5 20 000 89.0 0.080 52 272 4050.438 11.1 27 000 120 0.108 69.7 367 5480.500 12.7 36 000 160 0.144 92.9 490 7300.600 15.2 54 000 240 0.216 139 737 1090Grade 270 18600.375 9.53 23 000 102 0.085 55 290 4300.438 11.1 31 000 138 0.115 74.2 390 5800.500 12.7 41 300 184 0.153 98.7 520 7
26、800.520 13.2 45 000 200 0.167 108 570 8400.563 14.3 51 700 230 0.192 124 650 9700.600 15.2 58 600 261 0.217 140 740 11000.620 15.7 62 800 279 0.231 150 780 12000.700 17.8 79 400 353 0.294 190 1000 1500A416/A416M 17a26.3 Yield StrengthYield strength in pounds kN shall be measured at 1.0 % extension u
27、nder load. The minimum yield strengthshall be 90 % of the breaking strength listed in Table 1. Initial loads for the test and minimum yield strengths are listed in Table2.6.3.1 The extension under load shall be measured by an extensometer calibrated with the smallest division not larger than0.0001 i
28、n./in. 0.0001 mm/mm of gage length.6.4 ElongationThe total elongation under load shall not be less than 3.5 % using a gage length of not less than 24 in. 600mm. It shall be permissible to determine the total elongation value by adding, to the 1.0 % yield extension, the percent extensionor movement b
29、etween the jaws gripping the strand after yield determination. The percent is calculated on the new base length ofjaw-to-jaw distance.6.5 Relaxation PropertiesStrand shall have relaxation losses of not more than 2.5 % when initially loaded to 70 % of specifiedminimum breaking strength or not more th
30、an 3.5 % when loaded to 80 % of specified minimum breaking strength of the strandafter 1000 hours of testing.6.5.1 If required, relaxation evidence shall be provided from the manufacturers records of tests on similarly dimensioned strandof the same grade.7. Dimensions and Permissible Variations7.1 T
31、he size of the finished strand shall be expressed as the nominal diameter of the strand in inches millimetres.7.2 The diameter of the center wire of any strand shall be larger than the diameter of any outer wire in accordance with Table3.TABLE 2 Yield Strength RequirementsNominal Diameter ofStrand i
32、n. mm Initial Load, lbf kNMinimum Load at 1.0 %Extension, lbf kNGrade 250 17250.250 6.4 900 4.0 8 100 36.00.313 7.9 1 450 6.5 13 050 58.10.375 9.5 2 000 8.9 18 000 80.10.438 11.1 2 700 12.0 24 300 108.10.500 12.7 3 600 16.0 32 400 144.10.600 15.2 5 400 24.0 48 600 216.2Grade 270 18600.375 9.53 2 300
33、 10.2 20 700 92.10.438 11.1 3 100 13.8 27 900 124.10.500 12.7 4 130 18.4 37 170 165.30.520 13.2 4 500 20.0 40 500 180.10.563 14.3 5 170 23.0 46 530 207.00.600 15.2 5 860 26.1 52 740 234.60.620 15.7 6 280 27.9 56 520 251.40.700 17.8 7 940 35.3 71 500 318.0TABLE 3 Diameter Relation Between Center and
34、Outer WiresNominal Diameter of Strand, in.mmMinimum Difference Between CenterWire Diameter and Diameter of AnyOuter Wire, in. mmGrade 250 17250.250 6.4 0.001 0.0250.313 7.9 0.0015 0.0380.375 9.5 0.002 0.0510.438 11.1 0.0025 0.0640.500 12.7 0.003 0.0760.600 15.2 0.004 0.102Grade 270 18600.375 9.53 0.
35、002 0.0510.438 11.1 0.0025 0.0640.500 12.7 0.003 0.0760.520 13.2 0.003 0.0760.563 14.3 0.0035 0.0890.600 15.2 0.004 0.1020.620 15.7 0.004 0.1020.700 17.8 0.0045 0.114A416/A416M 17a37.3 Permissible Variations in Diameter:7.3.1 All Grade 250 1725 strand shall conform to a size tolerance of 60.016 in.
36、60.40 mm from the nominal diametermeasured across the crowns of the wires.7.3.2 All Grade 270 1860 strand shall conform to a size tolerance of +0.026, 0.006 in. +0.65, 0.15 mm from the nominaldiameter measured across the crowns of the wires.7.3.3 Variation in cross-sectional area and in unit stress
37、resulting therefrom shall not be cause for rejection provided that thediameter differences of the individual wires and the diameters of the strand are within the tolerances specified.7.4 It shall be permitted to furnish specially dimensioned strands with nominal diameters up to 0.750 in. 19 mm. The
38、breakingstrength shall be defined, and the yield strength, as defined in 6.3, shall not be less than 90 % of the specified minimum breakingstrength. All other requirements shall apply.8. Workmanship, Finish, and Appearance8.1 Joints:8.1.1 There shall be no strand joints or strand splices in any leng
39、th of the finished strand unless specifically permitted by thepurchaser.8.1.2 During the process of manufacture of individual wires for stranding, welding shall be permitted only prior to or at the sizeof the last thermal treatment, for example, patenting or controlled cooling. There shall be no wel
40、ds in the wire after it has beendrawn through the first die in the wire drawing except as provided in 8.1.3.8.1.3 During fabrication of the strand, butt-welded joints are permitted in the individual wires, provided there shall not be morethan one such joint in any 150-ft 45-m section of the finished
41、 strand.8.1.4 When specifically ordered as “Weldless,” a product free of welds shall be furnished. When “Weldless” is specified, thestrand is produced as one continuous length with no welds as allowed by 8.1.3.8.2 The finished strand shall be uniform in diameter and shall be free of imperfections.8.
42、3 When the strand is cut without seizings, the wire shall not fly out of position. If any wire flies out of position and can bereplaced by hand, the strand shall be considered satisfactory.8.4 The strand shall not be oiled or greased. Slight rusting, provided it is not sufficient to cause pits visib
43、le to a person withnormal or corrected vision, shall not be cause for rejection.NOTE 2Guidance for evaluating the degree of rusting on prestressed concrete strand is presented in Sason.49. Sampling9.1 Test specimens cut from either end of the reel or reelless pack are permitted. Any specimen found t
44、o contain a wire jointshall be discarded and a new specimen obtained.10. Number of Tests10.1 One test specimen shall be taken from each 30-ton 27-tonne production lot of finished strand,strand and tested forbreaking strength, yield strength, and elongation.11. Inspection11.1 If outside inspection is
45、 required, the manufacturer shall afford the inspector representing the purchaser reasonable accessto the facilities, which concern the manufacture of the material ordered, to satisfy the inspector that the material is being furnishedin accordance with this specification. All tests and inspections s
46、hall be made at the place of manufacture prior to shipment, unlessotherwise agreed upon at the time of purchase, and shall be so conducted as not to interfere unnecessarily with the manufacturersoperations. Inspection of the low-relaxation, seven-wire steel strand shall be agreed upon between the pu
47、rchaser and themanufacturer as part of the purchase order or contract.12. Rejection12.1 Failure of any test specimen to comply with the requirements of the specification shall constitute grounds for rejection ofthe production lot represented by the specimen.12.2 The production lot shall be resubmitt
48、ed for inspection by testing a specimen from each reel or reelless pack and sortingout non-conforming material.12.3 If there is a reasonable doubt in the initial testing as to the ability of the strand to meet any requirement of this specification,two additional tests shall be made on specimens of strand from the same reel or reelless pack, and if failure occurs in either ofthese tests, the strand shall be rejected.4 Sason, A.S., “Evaluation of Degree of Rusting on Prestressed Concrete Strand,” PCI Journal, Precast/Prestressed C
