1、Designation: A 722/A 722M 07Standard Specification forUncoated High-Strength Steel Bars for PrestressingConcrete1This standard is issued under the fixed designationA 722/A 722M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the y
2、ear 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 uncoated high-strength steelbars intended for use in pretensioned and post-tensione
3、dprestressed concrete construction or in prestressed groundanchors. Bars are of a minimum ultimate tensile strength levelof 1035 MPa (150 000 psi).1.2 Two types of bars are provided: Type I bar has a plainsurface and Type II bar has surface deformations.1.3 Supplementary requirements of an optional
4、nature areprovided. They shall apply only when specified by the pur-chaser.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.2. Referenced Documents2.1 ASTM Standards:2A 370 Test Methods and Definitions for Mechanical Testing
5、of Steel ProductsA 700 Practices for Packaging, Marking, and LoadingMethods for Steel Products for ShipmentE30 Test Methods for Chemical Analysis of Steel, CastIron, Open-Hearth Iron, and Wrought Iron32.2 Government Standards:4MIL-STD-129 Marking for Shipment and Storage2.3 U.S. Federal Standards:4F
6、ed. Std. 123 Marking for Shipment (Civil Agencies)3. Ordering Information3.1 Orders for material under this specification shouldinclude the following information:3.1.1 Quantity,3.1.2 Name of material (uncoated high-strength bars forprestressing concrete),3.1.3 ASTM designation and year of issue,3.1.
7、4 Size and length,3.1.5 Type,3.1.6 Special inspection requirements, if desired (see Sec-tion 12),3.1.7 Special preparation for delivery, if desired (see Sec-tion 11),3.1.8 Load-elongation curve, if required (see Section 15),and3.1.9 Supplementary requirements, if desired.NOTE 1A typical ordering des
8、cription is as follows: 50 uncoatedhigh-strength steel bars for prestressing concrete to ASTM A 722/A 722M _; 26 mm diameter, 12.20 m long, Type II; packed inaccordance with A 700; meeting supplementary bending properties.4. Materials and Manufacture4.1 The bars shall be rolled from properly identif
9、ied heats ofingot cast or strand cast steel. The standard sizes and dimen-sions of Type I and II bars shall be those listed in Table 1 andTable 2, respectively.4.2 The bars shall be subjected to cold-stressing to not lessthan 80 % of the minimum ultimate strength, and then shall bestress-relieved, t
10、o produce the prescribed mechanical proper-ties.5. Chemical Composition5.1 An analysis of each heat of steel shall be made by themanufacturer from test samples taken during the pouring ofeach heat.5.1.1 Choice and use of chemical composition and alloyingelements, to produce the mechanical properties
11、 of the finishedbar prescribed in 6.2, shall be made by the manufacturer,subject to the limitations in 5.1.2.5.1.2 On heat analysis, phosphorus and sulfur shall notexceed the following:Phosphorus 0.040 %Sulfur 0.050 %1This specification is under the jurisdiction of ASTM Committee A01 on Steel,Stainl
12、ess Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved March 1, 2007. Published March 2007. Originallyapproved in 1975. Last previous edition approved in 2005 as A 722/A 722M 06.2For referenced ASTM standards, visit the AST
13、M 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.3Withdrawn.4Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Av
14、e., Philadelphia, PA 19111-5098, http:/www.dodssp.daps.mil.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.5.2 A product analysis may be made by the purchaser fromthe
15、finished bar representing each cast or heat of steel. Thephosphorus and sulfur contents thus determined shall notexceed the limits specified in 5.1.2 by 0.008 %.5.3 Test Methods E30shall be used for referee purposes.6. Mechanical Properties6.1 All testing for mechanical properties shall be performed
16、in accordance with the requirements of Test Methods andDefinitions A 370.6.2 Tensile Properties:6.2.1 Finished bars shall have a minimum ultimate tensilestrength of 1035 MPa (150 000 psi).6.2.2 The minimum yield strength ofType I andType II barsshall be 85 % and 80 %, respectively, of the minimum ul
17、timatetensile strength of the bars. The yield strength shall bedetermined by either of the methods described in Test Methodsand Definitions A 370; however, in the extension under loadmethod, the total strain shall be 0.7 %, and in the offset methodthe offset shall be 0.2 %.6.2.3 The minimum elongati
18、on after rupture shall be 4.0 %in a gage length equal to 20 bar diameters, or 7.0 % in a gagelength equal to 10 bar diameters.6.3 Test SpecimensTension tests shall be made usingfull-size bar test specimens. Machined reduced section testspecimens are not permitted. All unit stress determinationsshall
19、 be based on the nominal area shown in Table 1 or theeffective area shown in Table 2.6.4 Number of TestsThe number of tensile specimenstested shall be one from each 36 Mg (39 tons) or fractionthereof, of each size of bar rolled from each heat but not lessthan two from each heat. The specimens shall
20、be randomlyselected following the final processing operation.6.5 Retests:6.5.1 If any tensile property of any tension test specimen isless than that specified, and any part of the fracture is outsidethe middle third of the gage length, as indicated by scribescratches marked on the specimen before te
21、sting, a retest shallbe allowed.6.5.2 If the results of an original tension test fail to meetspecified requirements, two additional tests shall be made onsamples of bar from the same heat and bar size, and if failureoccurs in either of these tests, the bar size from that heat shallbe rejected.6.5.3
22、If any test specimen fails because of mechanicalreasons such as failure of testing equipment, it shall bediscarded and another specimen taken.6.5.4 If any test specimen develops flaws, it shall bediscarded and another specimen of the same size bar from thesame heat substituted.7. Requirements for De
23、formations7.1 Material furnished as Type II bar shall have deforma-tions spaced uniformly along the length of the bar. Thedeformations on opposite sides of the bar shall be similar insize and shape. The average spacing or distance betweendeformations on both sides of the bar shall not exceed sevente
24、nths of the nominal diameter of the bar.7.2 The minimum height and minimum projected area of thedeformations shall conform to the requirements shown in Table3.7.3 Mechanical CouplingFor those bars having deforma-tions arranged in a manner to permit coupling of the bars witha screw-on type coupler, i
25、t shall be the responsibility of thefinished-bar manufacturer to demonstrate that a bar cut at anypoint along its length may be coupled to any other length of barand that a coupled joint supports the minimum specifiedultimate tensile strength of the coupled bars. The coupler typeshall be provided or
26、 designed by the finished-bar manufacturer.8. Measurements of Deformations8.1 The average spacing of deformations shall be deter-mined by dividing a measured length of the bar specimen bythe number of individual deformations and fractional parts ofdeformations on any one side of the bar specimen.Ame
27、asuredlength of the bar specimen shall be considered the distanceTABLE 1 Dimensions for Type I (Plain) BarNominal Diameter Nominal Mass (Weight) Nominal AreaAmm in. kg/m lb/ft mm2in.21934 2.23 1.50 284 0.442278 3.04 2.04 387 0.6025 1 3.97 2.67 503 0.7829 118 5.03 3.38 639 0.9932 114 6.21 4.17 794 1.
28、2335 138 7.52 5.05 955 1.48AThe nominal area is determined from the nominal diameter in inches. Valueshave been converted from inch-pound units to metric units.TABLE 2 Dimensions for Type II (Deformed) BarNominal DiameterANominal Mass (Weight) Nominal AreaBmm in. kg/m lb/ft mm2in.21558 1.46 0.98 181
29、 0.282034 2.22 1.49 271 0.4226 1 4.48 3.01 548 0.8532 114 6.54 4.39 806 1.2536 138 8.28 5.56 1019 1.5846 134 13.54 9.10 1664 2.5865 212 27.10 18.20 3331 5.16ANominal diameters are for identification only. Values have been converted frommetric to inch-pound units.BThe nominal area is determined from
30、the bar weight less 3.5 % for theineffective weight of the deformations.TABLE 3 Deformation Dimensions for Type II BarNominalDiameterDeformation DimensionsMaximumAverageSpacingMinimumAverageHeightMinimumProjectedAreaAmm in. mm in. mm in. mm2/mm in.2/in.1558 11.1 0.44 0.7 0.03 2.4 0.092034 13.3 0.52
31、1.0 0.04 3.4 0.1326 1 17.8 0.70 1.3 0.05 4.4 0.1732 114 22.5 0.89 1.6 0.06 5.4 0.2136 138 25.1 0.99 1.8 0.07 6.1 0.2446 134 30.1 1.19 2.2 0.09 7.3 0.2965 212 44.5 1.75 2.9 0.11 9.7 0.38ACalculated from equation, min projected area = 0.75pdh/swhere:d = nominal diameter,h = minimum average height, and
32、s = maximum average spacing.A 722/A 722M 072from a point on a deformation to a corresponding point on anyother deformation on the same side of the bar.8.2 The average height of deformations shall be determinedfrom measurements made on not less than two typical defor-mations. Determinations shall be
33、based on three measurementsper deformation: one at the center of the overall length, and theother two at the quarter points of the overall length.8.3 To indicate adequately the conformity to the dimen-sional requirements, measurements shall be taken at randomfrom one bar from each 30 Mg (33 tons) of
34、 each lot or fractionthereof.8.4 Insufficient height, insufficient projected area, or exces-sive spacing of deformations shall not constitute cause forrejection unless it has been clearly established by determina-tions on each lot that typical deformation height or spacingdoes not conform to the min
35、imum requirements prescribed inSection 7. No rejection shall be made on the basis of measure-ments if fewer than ten adjacent deformations on each side ofthe bar are measured.NOTE 2The term “lot” shall mean all bars of the same nominal mass(weight) per metre (linear foot) contained in an individual
36、shipping releaseor shipping order.9. Permissible Variation in Size or Weight9.1 For Type I bars, the permissible variation from thenominal diameter specified in Table 1 shall not exceed +0.75,0.25 mm (+0.030, 0.010 in.).9.2 For Type II bars, the permissible variation from thenominal weight specified
37、 in Table 2 shall not exceed +3 %,2 %.10. Finish10.1 The bars shall be free of defects injurious to themechanical properties and shall have a workmanlike finish.11. Packaging and Package Marking11.1 Packaging, marking, and loading for shipment shall bein accordance with Practices A 700.11.2 When spe
38、cified in the contract or order, and for directprocurement by or direct shipment to the U.S. government,marking for shipment, in addition to requirements specified inthe contract or order, shall be in accordance with MIL-STD-129 for military agencies and with Fed. Std. No. 123 for civilagencies.11.3
39、 Unless otherwise specified in the contract or order, barsshall be grouped by size. Each bundle or lift shall be taggedshowing the heat number, bar size, specification number(Specification A 722/A 722M), and the identity of the finishedbar manufacturer. The tags shall display the following state-men
40、t “High Strength Prestressing Bars”. Both ends of each barshall be painted yellow.12. Inspection12.1 The inspector representing the purchaser shall havefree entry, at all times while work on the contract of thepurchaser is being performed, to all parts of the manufacturersworks that concern the manu
41、facture of the material ordered.The manufacturer shall afford the inspector all reasonablefacilities to satisfy him that the material is being furnished inaccordance with this specification. All tests (except productanalysis) and inspection, shall be made at the place ofmanufacture prior to shipment
42、, unless otherwise specified, andshall be so conducted as not to interfere unnecessarily with theoperation of the works.12.2 If specified in the purchase order, the purchaser shallreserve the right to perform any of the inspection set forth inthe specification where such inspections are deemed neces
43、saryto assure that the material furnished conforms to prescribedrequirements.12.3 If outside inspection is waived, the finished-bar manu-facturers certification that the material has been tested inaccordance with, and meets the requirements of, this specifi-cation, shall be the basis of acceptance o
44、f the material.13. Rejection13.1 Unless otherwise specified, any rejection based on testsmade in accordance with 5.2 shall be reported to the manufac-turer within 5 working days from the receipt of samples by thepurchaser.13.2 Material that shows injurious defects subsequent to itsacceptance at the
45、manufacturers works shall be subject torejection, and the manufacturer shall be notified.14. Rehearing14.1 Samples tested in accordance with 5.2 that representrejected material shall be preserved for two weeks from thedate rejection is reported to the manufacturer. In case ofdissatisfaction with the
46、 results of the tests, the manufacturershall be permitted to make claim for a rehearing within thattime.15. Certification15.1 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
47、thebasis of acceptance of the material. The certification shallinclude the specification number, year-date of issue, andrevision letter, if any.15.2 The manufacturer shall, when required in the order,furnish a representative load-elongation curve for each size andtype of bar shipped.15.3 A modulus o
48、f elasticity value of 205 GPa (29 700 000psi) shall be used for the purpose of elongation calculation forType II bars.NOTE 3Experience has shown that plotted load-elongation curvesfrom mill tests on Type II bars vary excessively and are not sufficientlyreliable for use in calculating modulus of elas
49、ticity values.15.4 A material test report, certificate of 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 requirements of the invoked ASTMstandard(s) and conform to any existing EDI agreement be-tween the purchaser and the supplier. Notwithstanding theabsence of a signature, the organization submitting the EDItransmission
