1、Designation:A416/A416M10 Designation: A416/A416M 12Standard Specification forSteel Strand, Uncoated Seven-Wire 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 ca
2、se 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 use by agencies of the Department of Defense.1. Scope*1.1This spec
3、ification covers two types and two grades of seven-wire, uncoated steel strand for use in pretensioned andpost-tensioned prestressed concrete construction. The two types of strand are low-relaxation and stress-relieved (normal-relaxation). Low-relaxation strand shall be regarded as the standard type
4、. Stress-relieved (normal-relaxation) strand will not befurnished unless specifically ordered, or by arrangement between purchaser and supplier. Grade 1725 250 and Grade 1860 270have minimum ultimate strengths of 1725 MPa 250 ksi and 1860 MPa 270 ksi, respectively, based on the nominal area of thest
5、rand.1.2The values stated in either inch-pound units or SI units are to be regarded as standard. Within the text, the inch-pound unitsare shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be usedindependently of the other. Combining values fro
6、m the two systems may result in nonconformance with the specification.1.3The supplementary requirements in S1 shall be specified for 15.2-mm 0.600-in. diameter uncoated seven-wire steel strandif needed for applications in prestressed ground anchors.1.1 This specification covers two types and two gra
7、des of seven-wire, uncoated steel strand for use prestressed concreteconstruction. The two types of strand are low-relaxation and stress-relieved (normal-relaxation). Low-relaxation strand is to beregarded as the standard type. Stress-relieved (normal-relaxation) strand will not be furnished unless
8、specifically ordered. Grade250 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 requirement (S1) is provided for use where bond strength testing of 0.600-in. 15.24-mm diameter Grad
9、e270 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 This specification is applicable for orders in either inch-pound units (as Specification A416) or in SI units (as specifica
10、tionA416M).1.4 The values stated 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. Combin
11、ing values from the two systems may result in non-conformance with the specification.2. Referenced Documents2.1 ASTM Standards:2A981/A981M Test Method for Evaluating Bond Strength for 15.2 mm (0.6 in.) 0.600-in. 15.24-mm Diameter PrestressingSteel Prestressing Strand, Grade 270 1860, Uncoated, Used
12、in Prestressed Ground AnchorsA1061/A1061M Test Methods for Testing Multi-Wire Steel Strand2.2 U.S. Military Standards:3MIL-STD-129 Marking for Shipment and StorageMIL-STD-163 Steel Mill Products Preparation for Shipment and Storage Marking for Shipment and Storage2.3 U.S. Federal Standard:3Fed. Std.
13、 No. 123 Marking for Shipments (Civil Agencies)1This specification is under the jurisdiction ofASTM CommitteeA01 on Steel, Stainless Steel and RelatedAlloys and is the direct responsibility of SubcommitteeA01.05on Steel Reinforcement.Current edition approved April 1, 2010.2012. Published July 2010.M
14、ay 2012. Originally approved in 1957. Last previous edition approved in 20062010 as A416 106.DOI: 10.1520/A0416_A0416M-102.2For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refe
15、r to the standards Document Summary page on the ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-50948, http:/dodssp.daps.dla.mil.1This document is not an ASTM standard and is intended only to provide the user of
16、an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as publ
17、ished by ASTM is to be considered the official document.*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.3. Terminology3.1 Definitions of Terms Specific to This Standard
18、:3.1.1 strand, na 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.3.1.1.1 DiscussionThe direction of lay may be either right- or left-hand, however, strands of
19、 different lays should not bespliced together.4. Ordering Information4.1Orders for seven-wire low-relaxation or stress-relieved (normal-relaxation) strand under this specification should include thefollowing information:4.1.1Quantity (metres feet),4.1.2Diameter of strand,4.1 It shall be the responsi
20、bility of the purchaser to specify all requirements that are necessary for material ordered under thisspecification. Such requirements to be considered include, but are not limited to, the following:4.1.1 Quantity (feet metres),4.1.2 Nominal diameter of strand,4.1.3 Grade of strand,4.1.4 Type of str
21、and,4.1.5Packaging,4.1.6ASTM designation and year of issue, and4.1.7Special requirements, if any.NOTE1A typical ordering description is as follows: 25600 m 84000 ft, 13 mm 0.5 in., Grade 1860 270 low-relaxation strand, in 3600-m12000-ft reelless packs to ASTM A416/A416M_.4.1.5 Weldless, if desired (
22、8.1)4.1.6 Outside inspection, if required (11.1),4.1.7 Load-elongation curve, if desired (13.2),4.1.8 Packaging (14.1),4.1.9 Supplementary Requirement S1, if desired, and4.1.10 ASTM designation and year of issue.5. Materials and Manufacture5.1 Base MetalThe base metal shall be carbon steel of such q
23、uality that when drawn to wire, fabricated 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.NOTE2This 1This product is a composi
24、te of seven wires and is produced only to mechanical properties only. meet the prescribed mechanicalproperties. The chemical composition of 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 more than o
25、ne heat may be used in the manufacture of a reel or reelless pack. Traceability is based on pack identity of reelsor reelless packs as maintained and reported by the manufacturer.5.3 TreatmentAfter stranding, low-relaxation strand shall be subjected to a continuous thermal-mechanical treatment topro
26、duce the prescribed mechanical properties. For stress-relieved (normal-relaxation) strand, only thermal treatment is necessary.Temper colors which result from the stress-relieving operation are considered normal for the finished appearance of this strand.6. Mechanical Property Requirements6.1Tests6.
27、1 Tests for mechanical properties shall be conducted in accordance with Test Methods A1061/A1061M. Low-relaxation strand shall also be tested as prescribed in Test Methods A1061/A1061M.6.2 Breaking StrengthThe breaking strength of the finished strand shall conform to the requirements prescribed in T
28、able 1.6.3 Yield StrengthYield strength in kN poundspounds kN shall be measured at 1 % extension under load. The minimumyield strength shall be 90 % for low-relaxation strand and 85 % for stress-relieved (normal-relaxation) strand of the breakingstrength listed in Table 1. Initial loads for the test
29、 and minimum yield strengths are listed in Table 2.6.3.1 The extension under load shall be measured by an extensometer calibrated with the smallest division not larger than0.0001 mm/mmin./in. 0.0001 in./in.mm/mm of gage length.6.4 ElongationThe total elongation under load shall not be less than 3.5
30、% using a gage length of not less than 600 mm 24in.24 in. 600 mm. It shall be permissaible to determine the total elongation value by adding, to the 1.0 % yield extension, thepercent extension or movement between the jaws gripping the strand after yield determination. The percent is calculated on th
31、enew base length of jaw-to-jaw distance.6.5 Relaxation PropertiesLow-relaxation strand shall have relaxation losses of not more than 2.5% when initially loaded to70% of specified minimum breaking strength or not more than 3.5% when loaded to 80% of specified minimum breaking strengthof the strand af
32、ter 1000 h tested under the conditions listed in 6.5.1 through 6.5.7.A416/A416M 1226.5.1If required, relaxation evidence shall be provided from the manufacturers records of tests on similarly dimensioned strandof the same grade.6.5.2The temperature of the test specimen shall be maintained at 20 6 2C
33、 68 6 3.5F.6.5.3The test specimen shall not be subjected to loading prior to the relaxation test.6.5.4The initial load shall be applied uniformly over a period of not less than 3 min and not more than 5 min, and the gage lengthshall be maintained constant; load relaxation readings shall commence 1 m
34、in after application of the total load.6.5.5Over-stressing of the test specimen during the loading operation shall not be permitted.6.5.6The duration of the test shall be 1000 h or a shorter period of at least 200 h, provided it can be shown by records that anextrapolation of the shorter period test
35、 results to 1000 h will provide similar relaxation values as the full 1000 h test.6.5.7The test gage length shall be at least 60 times the nominal diameter. If this gage length exceeds the capacity of theextensometer or testing machine, then it shall be permitted to substitute a gage length of 40 ti
36、mes the nomimal strand diameter.Low-relaxation strand shall have relaxation losses of not more than 2.5 % when initially loaded to 70 % of specified minimumbreaking strength or not more than 3.5 % when loaded to 80 % of specified minimum breaking strength of the strand after 1000hours of testing.6.5
37、.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 The size of the finished strand shall be expressed as the nominal diameter of the strand in millimetres inches. i
38、nchesmillimetres.7.2 The diameter of the center wire of any strand shall be larger than the diameter of any outer wire in accordance with Table3.7.3 Permissible Variations in Diameter:7.3.1 All Grade 1725 250250 1725 strand shall conform to a size tolerance of 60.40 mm 60.016 in.60.016 in. 60.40mm f
39、rom the nominal diameter measured across the crowns of the wires.7.3.2 All Grade 1860 270270 1860 strand shall conform to a size tolerance of +0.65, 0.15 mm +0.026, 0.006 in.+0.026,0.006 in. +0.65, 0.15 mm from the nominal diameter measured across the crowns of the wire.TABLE 1 Breaking Strength Req
40、uirementsNominal Diameter ofStrand Des, ignation No.mmDMianimum BreakingSterength of Strand, mmlbf in.kNMinimum BreakingStrengthof Strand, kN lbfSteel Area of Strand, mmin.2in.mm2WeightGrade 17 25 250Grade 250 17256 6.4 0.250 40.0 9 000 23.2 0.0360.250 6.4 9 000 40.0 0.036 23.2 122 0.0368 7.9 0.313
41、64.5 14 500 37.4 0.0580.313 7.9 14 500 64.5 0.058 37.4 197 0.0589 9.5 0.375 89.0 20 000 51.6 0.0800.375 9.5 20 000 89.0 0.080 51.6 272 0.08011 11.1 0.438 120.1 27 000 69.7 0.1080.438 11.1 27 000 120.1 0.108 69.7 367 0.10813 12.7 0.500 160.1 36 000 92.9 0.1440.500 12.7 36 000 160.1 0.144 92.9 490.144
42、15 15.2 0.600 240.2 54 000 139.4 0.2160.600 15.2 54 000 240.2 0.216 139.4 737 10941094 737Grade1860 270Grade 270 18609 9.53 0.375 102.3 23 000 54.8 0.0850.375 9.53 23 000 102.3 0.085 54.8 290.08511 11.11 0.438 137.9 31 000 74.2 0.1150.438 11.11 31 000 137.9 0.115 74.2 390 513 12.7 0 0.500 183.7 41 3
43、00 98.7 0.1530.500 12.70 41 300 183.7 0.153 98.7 5313a 13.20 0.520 200.2 45000 107.7 0.1670.520 13.20 45 000 200.2 0.167 107.7 56714 14.29 0.563 230.0 51 700 123.9 0.1920.563 14.29 51 700 230.0 0.192 123.9 651 9215 15.24 0.600 260.7 58 600 140.0 0.2170.600 15.24 58 600 260.7 0.217 140.0 740 1716 15.
44、75 0.62 0 277.4 62370 149.2 0.2310.620 15.75 62 370 277.4 0.231 149.2 778 118 17.78 0.700 353.2 79 400 189.7 0.2940.700 17.78 79 400 353.2 0.294 189.7 10.294A416/A416M 1237.3.3 Variation in cross-sectional area and in unit stress resulting therefrom shall not be cause for rejection provided that the
45、diameter differences of the individual wires and the diameters 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 19 mm 0.75
46、0 in.0.750 in. 19 mm. The breaking strength shall bedefined, and the yield strength, as defined in 6.3, shall not be less than 90 % and 85 % of the specified minimum breaking strengthfor low-relaxation and stress-relieved (normal-relaxation) strands, respectively. All other requirements shall apply.
47、8. Workmanship, Finish, and Appearance8.1 Joints:8.1.1 There shall be no strand joints or strand splices in any length of the completed strand unless specifically permitted by thepurchaser.8.1.2 During the process of manufacture of individual wires for stranding, welding shall be permitted only prio
48、r to or at the sizeof the last thermal treatment, for example, patenting or controlled cooling. There shall be no welds 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 45-m 150-ft150-ft 45-m section of the completed strand.8.1.4 When specifically ordered as “Weldless,” a product free of welds shall be furnished. When “Weldless” is specified, thes
