1、Designation: A 648 04aStandard Specification forSteel Wire, Hard Drawn for Prestressing Concrete Pipe1This standard is issued under the fixed designation A 648; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers two classes of uncoated, high-strength, hard-drawn steel wire for use in the manufacture ofprestress
3、ed concrete pipe. In application, the wire is helicallywrapped on the pipe maintaining tension by mechanical meansnot including drawing dies.1.2 The values stated in inch-pound units are to be regardedas the standard. The values given in parentheses are providedfor information only.1.3 Supplementary
4、 requirements describe hydrogen em-brittlement resistance test acceptance criteria.1.4 The following caveat pertains only to the test methodportions of this specification, 6.2.3 and 6.4.3: This standarddoes not purport to address the safety concerns, if any,associated with its use. It is the respons
5、ibility of the user of thisstandard to establish appropriate safety and health practicesand determine the applicability of regulatory limitations priorto use.2. Referenced Documents2.1 ASTM Standards:2A 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsA 510 Specification for G
6、eneral Requirements for WireRods and Coarse Round Wire, Carbon SteelA 700 Practices for Packaging, Marking, and LoadingMethods for Steel Products for Domestic ShipmentE 328 Test Methods for Stress Relaxation Tests for Materi-als and Structures2.2 ANSI Standard:C 304 Standard for Design of Prestresse
7、d Concrete CylinderPipe33. Ordering Information3.1 Orders for material to this specification should includethe following information:3.1.1 Quantity (weight),3.1.2 Name of material (hard-drawn steel wire for prestress-ing concrete pipe),3.1.3 Wire diameter (see Table 1),3.1.4 Class (see Table 1),3.1.
8、5 Packaging (see Section 11),3.1.6 ASTM designation and year of issue, and3.1.7 Special requirements, if any (see Supplementary Re-quirements).NOTE 1A typical ordering description is as follows: 100 000-lb,Hard-Drawn Steel Wire for Prestressing Concrete Pipe, 0.192 in. indiameter, Class III, 1500-lb
9、 coils, to ASTM A 648 _.4. Manufacture4.1 The steel shall be made by the open-hearth, basic-oxygen, or electric-furnace process.4.2 The steel shall be free of injurious piping and unduesegregation.4.3 The wire shall be cold drawn to produce the desiredmechanical properties. The wire manufacturer sha
10、ll take de-pendable precautions during wire drawing to preclude detri-mental strain aging of the wire.NOTE 2Allowing wire to remain at elevated temperatures, such as400F (204C) for more than5sor360F (182C) for more than 20 s, canresult in detrimental strain aging of the wire. Detrimentally strain ag
11、edwire typically has reduced ductility and increased susceptibility tohydrogen embrittlement.4.4 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.1This specification is under the jurisdiction of AST
12、M Committee A01 on Steel,Stainless Steel, and Related Alloys and is the direct responsibility of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved Sept. 1, 2004. Published September 2004. Originallyapproved in 1972. Last previous edition approved in 2004 as A 648 04.2For referenced
13、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 American National Standards Institute, 25 W. 43rd St., 4thFlo
14、or, New York, NY 10036.1*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. Chemical Requirements5.1 The cast or heat analysis of the steel shall conform to thechemical
15、requirements specified in Table 2.5.2 An analysis of each cast or heat of steel shall befurnished by the manufacturer showing the percentages of allthe elements specified in Table 2. The wire shall be subject topermissible variation for product analysis specified in Specifi-cation A 510, Table 7.6.
16、Mechanical RequirementsNOTE 3Mechanical requirements are applicable only prior to orduring pipe manufacture.6.1 Test SpecimensWire specimens for tensile and tor-sion tests shall be taken from either end of a coil but must berepresentative of that coils wire drawing conditions withregard to wire temp
17、erature.6.2 Tension Test:6.2.1 Tensile Requirements shall conform to those pre-scribed in Table 1 for the specified size and class.6.2.2 Number of TestsOne test specimen shall be takenfrom each coil.6.2.3 Test MethodThe tension test shall be made inaccordance with Test Methods and Definitions A 370,
18、 AnnexA4. Tension test reports shall include the coil number tested,the measured wire diameter, and the measured breakingstrength.6.2.4 Reduction of Area TestThe reduction of area re-quirement for the specimens used for the tension test in 7.1shall be a minimum of 35 % for 0.192 in. (4.88 mm) wire a
19、nd30 % for larger wire as described and tested in accordance withTest Methods and Definitions A 370, Annex A4.6.3 Relaxation Test:6.3.1 Number of TestsRelaxation test results shall beprovided for purposes of qualifying the procedures used tomanufacture wire for prestressing pipe. Relaxation test res
20、ultsshall include one sample each from a minimum of three coilsof wire from the same or different heats of steel where the wiresamples are of the same nominal size, the same class, andmanufactured using the same drawing machine and drawingprocedures. It shall be permissible to provide the relaxation
21、 testresults from the wire manufacturers historical records.6.3.2 Test MethodWire shall be tested as described inTest Methods E 328.6.3.3 Conditions of TestsThe conditions of the tests are:6.3.3.1 At least one of the tests performed shall have aduration of 1000 h minimum, and all other tests shall h
22、ave aduration of at least 200 h. Measurements shall be made andrecorded for at least five data points during each time intervalof (1) 0 to 10 h, (2) 10 to 100 h, and (3) 100 to 1000 h, exceptthat, if a test is terminated in less than 1000 h, measurementsshall be made for at least two data points in
23、the third interval.For tests terminated in less than 1000 h, the expected relaxationof the specimen at 1000 h shall be determined from the linearregression curve of stress loss on a logarithm time scale.6.3.3.2 The temperature of the test specimen shall bemaintained at 68 6 3.5F (20 6 2C).6.3.3.3 Th
24、e test specimen shall not be subjected to loading,including sample straightening, prior to the relaxation test,except that it shall be permissible to straighten the sample endsto fit in the test machine jaws.6.3.3.4 Loading shall be applied at an essentially constantrate over a period of not less th
25、an 3 min and not more than 5min until the initial load is reached. Thereafter, the gage lengthshall be maintained constant. Load relaxation readings shallcommence 1 min after the initial load has been reached.6.3.3.5 The initial load shall be 70 % of the specifedminimum breaking strength of the wire
26、. Overstressing of thetest specimen to a level greater than 70 % of the specifiedminimum breaking strength during loading shall not be per-mitted.6.3.3.6 The test gage length shall be at least 60 times thenominal diameter of the wire.6.3.3.7 The result of each relaxation test shall be reportedeither
27、 as the actual percent of stress loss after 1000 h or theextrapolated percent of stress loss after 1000 h as determinedfrom the linear regression curve.NOTE 4In accordance with ANSI/AWWA C 304, ordinary prestressedconcrete pipe design is based on an assumed maximum wire relaxation of7.48 % at 1000 h
28、. Wire with higher relaxation can be used, but the higherrelaxation loss must be known for consideration in the pipe design.TABLE 1 Tensile RequirementsWire Gage orFraction, in.Decimal Size,in. (mm)Class II Wire Class III WireMinimum TensileStrength,Aksi (MPa)Breaking Strength, lbf (kN) Minimum Tens
29、ileStrength,Aksi (MPa)Breaking Strength, lbf (kN)min max min max6 0.192 (4.88) 222 (1530) 6 430 (28.6) 7 300 (32.5) 252 (1740) 7 300 (32.5) 8 170 (36.3)1/4 0.250 (6.35) 211 (1450) 10 360 (46.1) 11 830 (52.6) 240 (1650) 11 780 (52.4) 13 250 (58.9)5/16 0.312 (7.92) 201 (1390) 15 370 (68.4) 17 660 (78.
30、6) 221 (1520) 16 900 (75.2) 19 190 (85.4)ABased on nominal wire diameter.TABLE 2 Chemical RequirementsNOTE 1Class I wire has been discontinued.Classes II and IIICarbon, % 0.500.85Manganese, % 0.501.10Phosphorus, max, % 0.030Sulfur, max, % 0.035Silicon, % 0.100.35Nitrogen, max, % 0.007Aluminum, % Tit
31、anium, % Chromium, % Nickel, % Molybdenum, % Copper, % Vanadium, % Note: Where “” appear in this table, there is no requirement or limit.A 648 04a26.4 Torsion Test:6.4.1 Torsion RequirementsTorsion requirements shallconform to those prescribed in Table 3 for the specified sizeand class.6.4.2 Number
32、of TestsOne test specimen shall be takenfrom each coil.6.4.3 Test MethodConduct the torsion test in accordancewith the following:6.4.3.1 Use a twist rate of 10 to 30 r/min.6.4.3.2 Load the wire with an axial force of from 0.5 to 2 %of the minimum breaking strength of the wire.6.4.3.3 Use a test spec
33、imen length, defined as the distancebetween the testing machine jaws, of a minimum of 8 in. (203mm).6.4.3.4 Use a minimum number of turns proportional to thelength of the test specimen based upon Table 3.6.4.3.5 The test shall be conducted to fracture, defined ascomplete separation of the broken end
34、s. The test specimensshall be inspected for primary break shear area and longitudinal(spiral) splitting following completion of the torsion test.(1) Primary Break ShearThe primary break face of thetest specimen shall have a clean, flush, full shear face,perpendicular to the wire axis (see Fig. 1).(2
35、) Longitudinal (Spiral) SplittingIf the fracturedspecimen shows evidence of a spiral split, either visiblewithout magnification (see Fig. 2) or by an offset in the wiresurfaces (see Fig. 3) detectable with a fingernail, a retest of thatcoil shall be conducted in accordance with 6.4.3.5 (3).(3) Retes
36、t for Splitting in Torsion The retest specimenshall have a minimum length of 8 in. (203 mm). The retest shallconsist of twisting the retest specimen proportionally to threetwists per 8 in. (203 mm) specimen length, at which point thetwisting shall be stopped and the specimen inspected while stillin
37、the torsion machine. A spiral split in this specimen, eithervisible without magnification or detectable with a fingernail,shall be cause for rejection of the coil.6.4.3.6 The tested coil number, specimen length, and totalnumber of turns shall be recorded.6.5 Mechanical Test Results Report The wire m
38、anufac-turer shall furnish a report listing the tensile, reduction of area,and torsion test results.7. Dimensions and Permissible Variations7.1 The diameter of the wire shall not vary from thatspecified by more than 60.002 in. (0.05 mm) in diameter normore than 0.002-in. (0.05-mm) out-of-round.8. Wo
39、rkmanship, Finish, and Appearance8.1 The surface of the wire as received shall be smooth andgenerally free of rust. A light oxidation film that does not causepitting of the wire surface visible to the unaided eye afterwiping or light cleaning, shall not be cause for rejection. Coilsof wire with visi
40、ble pitting shall be rejected.8.2 The wire shall not have detrimental piping, cross check-ing, torn surfaces, chatter marks, splits, die marks, scratches,pits, or seams.8.3 The wire shall not be kinked, improperly cast, or showa wavy condition.8.4 Each coil shall be one continuous length of wire,pro
41、perly coiled.8.5 The wire shall not be oiled or greased.9. Inspection9.1 The manufacturer shall afford the purchasers inspectorall reasonable facilities to satisfy him that the material is beingproduced and furnished in accordance with this specification.All tests and inspections may be made at the
42、place ofmanufacture prior to shipment and shall be so conducted as notto interfere unnecessarily with the operation of the work.10. Rejection Retesting, and Rehearing10.1 Failure of any specimen to meet the mechanicalrequirements of this specification when tested by the manufac-turer, except splitti
43、ng during torsion testing, shall be causeeither for rejection of the coil represented by the sample or forretesting two additional specimens from that coil. If eitheradditional specimen fails the retest for the mechanical require-ment in which the first specimen failed, the coil in questionshall be
44、rejected. Requirements for retesting coils which splitduring torsion testing are described in 6.4.3.5 (3).10.2 Any rejection based on tests made in accordance withthe specification shall be reported to the wire manufacturerwithin a reasonable period of time. The material must beadequately protected
45、and correctly identified in order that thewire manufacturer may make a proper investigation.TABLE 3 Torsion RequirementsWire Gage orFraction in.Decimal Size,in. (mm)Class II and Class III minturns per 8 in. (203 mm)6 0.192 (4.88) 101/4 0.250 (6.35) 85/16 0.312 (7.92) 7FIG. 1 Acceptable View of the B
46、reak Face.FIG. 2 Visible Longitudinal (Spiral) Splitting After Torsion TestingFIG. 3 End View of Offset Longitudinal (Spiral) Split After TorsionTestingA 648 04a311. Product Marking and Packaging11.1 The size of the wire, purchasers order number, ASTMspecification and class number, cast or heat numb
47、er, coilnumber, and name or mark of the manufacturer shall be markedon a tag securely attached to each coil of wire.11.2 Unless otherwise specified, packaging shall be inaccordance with the procedures in Practices A 700.12. Keywords12.1 prestressed concrete pipe; prestressing; steel wireSUPPLEMENTAR
48、Y REQUIREMENTSThe following supplementary requirements shall apply when specified by the purchaser order orcontract.S1. Hydrogen Embrittlement TestS1.1 ResultsFor a single diameter and class of wire, theresults of nine hydrogen embrittlement tests performed inaccordance with Test Method A 1032 shall
49、 be submitted to thepurchaser. No test shall result in a time-to-failure of less than75 hours. The results shall be derived from tests conductedanytime within the previous 12 months on wire of the samediameter and class and made from the same rod source as thewire being furnished. The hydrogen embrittlement test reportdescribed in Test Method A 1032 shall be submitted to thepurchaser at the time of delivery of wire or as agreed betweenpurchaser and wire manufacturer.S1.2 Test SpecimensFor a single diameter and class ofwire, three wi
