ASTM A722 A722M-2018 Standard Specification for High-Strength Steel Bars for Prestressed Concrete.pdf

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1、Designation: A722/A722M 18Standard Specification forHigh-Strength Steel Bars for Prestressed Concrete1This standard is issued under the fixed designation A722/A722M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of last

2、revision. A number in parentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers Type I and Type II high-strength steel bars intended for use in prestressed concreteconstruction

3、 or in prestressed ground anchors. Type I bars havea plain surface. Type II bars have surface deformations. Barsare of a minimum tensile strength level of 150 000 psi 1035MPa.1.2 A supplementary requirement (S1) is provided for usewhere bend tests of bars are required by the purchaser. Thesupplement

4、ary requirement applies only when specified in thepurchase order.1.3 The text of this specification references notes andfootnotes which provide explanatory material. These notes andfootnotes (excluding those in tables and figures) shall not beconsidered as requirements of the specification.1.4 This

5、specification is applicable for orders in eitherinch-pound units (as Specification A722) or in SI units (asSpecification A722M).1.5 The values stated in either inch-pound or SI units are tobe regarded separately as standard. Within the text, the SI unitsare shown in brackets. The values stated in ea

6、ch system maynot be exact equivalents; therefore, each system shall be usedindependently of the other. Combining values from the twosystems may result in non-conformance with the specification.1.6 This international standard was developed in accor-dance with internationally recognized principles on

7、standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2A370 Test Methods and Definitions for Mec

8、hanical Testingof Steel ProductsA700 Guide for Packaging, Marking, and Loading Methodsfor Steel Products for ShipmentA751 Test Methods, Practices, and Terminology for Chemi-cal Analysis of Steel Products2.2 Military Standard:3MIL-STD-129 Marking for Shipment and Storage2.3 U.S. Federal Standard:3Fed

9、. Std. 123 Marking for Shipment (Civil Agencies)3. Ordering Information3.1 Orders for high-strength steel bars under this specifica-tion shall contain the following information:3.1.1 Quantity,3.1.2 Size and length,3.1.3 Type I or Type II, and3.1.4 ASTM designation A722 A722M and year-date ofissue.3.

10、2 The purchaser shall have the option to specify additionalrequirements, including but not limited, to the following:3.2.1 Report on chemical composition (5.1),3.2.2 Special inspection requirements (14.2),3.2.3 Load-elongation curve (16.2),3.2.4 Special preparation for delivery, if desired (see Sec-

11、tion 17), and3.2.5 Supplementary requirement (S1).4. Materials and Manufacture4.1 The bars shall be rolled from properly identified heats ofmold-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.1This specifi

12、cation 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 Sept. 1, 2018. Published September 2018. Originallyapproved in 1975. Last previous edition approve

13、d in 2015 as A722/A722M 15.DOI: 10.1520/A0722_A0722M-18.2For 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.3Avai

14、lable from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/www.dodssp.daps.mil.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, P

15、A 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization

16、Technical Barriers to Trade (TBT) Committee.14.2 The bars shall be subjected to cold-stressing to not lessthan 80 % of the minimum tensile strength, and then shall bestress-relieved, to produce the prescribed tensile properties.5. Chemical Composition5.1 A chemical analysis of each heat of steel sha

17、ll bedetermined in accordance with Test Methods, Practices, andTerminology A751. The manufacturer shall make the analysison test samples taken during the pouring of the heat. Whenrequested in the purchase order or contract, the chemicalcomposition determined shall be reported to the purchaser.5.1.1

18、Choice and use of chemical composition and alloyingelements, to produce the tensile properties of the bars pre-scribed in Section 6, 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 %Sul

19、fur 0.050 %5.2 A product analysis may be made by the purchaser fromthe bar representing each heat of steel. The phosphorus andsulfur contents thus determined shall not exceed the limitsspecified in 5.1.2 by 0.008 %.6. Tensile Requirements6.1 Tension tests shall be conducted in accordance with TestMe

20、thods and Definitions A370.6.2 Bars shall have a minimum tensile strength of 150 000psi 1035 MPa.6.3 The minimum yield strength of Type I and Type II barsshall be 85 % and 80 %, respectively, of the minimum tensilestrength of the bars. The yield strength shall be determined byeither of the methods d

21、escribed in Test Methods and Defini-tions A370; however, in the extension under load method, thetotal strain shall be 0.7 %, and in the offset method the offsetshall be 0.2 %.6.4 The minimum elongation after rupture shall be 4.0 % ina gage length equal to 20 bar diameters, or 7.0 % in a gagelength e

22、qual to 10 bar diameters.7. Number of Tests7.1 The number of tension test specimens shall be one fromeach 39 tons 36 tonnes or fraction thereof, of each size of barrolled from each heat but not less than two tension testspecimens from each heat.7.2 For Type II bars, one set of dimensional property t

23、estsincluding bar weight mass, and spacing, height and projectedarea of deformations shall be made of each bar size rolled fromeach heat.8. Retests8.1 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

24、length, as indicated by scribescratches marked on the test specimen before testing, a retestshall be permitted.8.2 If the results of an original tension test specimen fail tomeet specified requirements, two additional tests shall be madeon specimens from the same heat and bar size, and if failureocc

25、urs in either of these tests, the bar size from that heat shallbe rejected.8.3 If any test specimen fails because of mechanical reasonssuch as failure of testing equipment, it shall be discarded andanother specimen taken.8.4 If any test specimen develops flaws, it shall be discardedand another speci

26、men of the same size bar from the same heatsubstituted.9. Test Specimens9.1 Tension test specimens shall be the full section of thebar as rolled. Machined-reduced section test specimens are notpermitted. All unit stress determinations shall be based on thenominal area shown in Table 1 or Table 2.10.

27、 Requirements for Deformations10.1 Type II bars shall have deformations spaced uniformlyalong the length of the bar. The deformations on opposite sidesof the bar shall be similar in size and shape. The averagespacing or distance between deformations on both sides of thebar shall not exceed seven-ten

28、ths of the nominal diameter ofthe bar.10.2 The minimum height and minimum projected area ofthe deformations shall conform to the requirements shown inTable 3.10.3 Mechanical CouplingFor those bars having deforma-tions arranged in a manner to permit coupling of the bars witha screw-on type coupler, i

29、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 barTABLE 1 Nominal Dimensions for Type I (Plain) BarsNominal Diameter Nominal Weight (Mass) Nominal AreaAin. mm lb/ft kg/m in.2mm234 19 1.50

30、2.23 0.44 28478 22 2.04 3.04 0.60 3871 25 2.67 3.97 0.78 503118 29 3.38 5.03 0.99 639114 32 4.17 6.21 1.23 794138 35 5.05 7.52 1.48 955ANominal area is determined from the nominal diameter in inches millimetres.TABLE 2 Nominal Dimensions for Type II (Deformed) BarsNominal DiameterANominal Weight (Ma

31、ss) Nominal AreaBin. mm lb/ft kg/m in.2mm258 15 0.98 1.46 0.28 18134 20 1.49 2.22 0.42 2711 26 3.01 4.48 0.85 548114 32 4.39 6.54 1.25 806138 36 5.56 8.28 1.58 1019134 46 9.10 13.54 2.58 1664212 65 18.20 27.10 5.16 33313 75 24.09 35.85 6.85 4419ANominal diameters are for identification only.BNominal

32、 area is determined from the bar weight mass less 3.50% for the weightmass of the deformations.A722/A722M 182and that a coupled joint is capable of developing the minimumspecified tensile strength of the coupled bars.11. Measurements of Deformations11.1 The average spacing of deformations shall be d

33、eter-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. A measuredlength of the bar specimen shall be considered the distancefrom a point on a deformation to a corresponding point on

34、 anyother deformation on the same side of the bar.11.2 The average height of deformations shall be deter-mined from measurements made on not less than two typicaldeformations. Determinations shall be based on three measure-ments per deformation: one at the center of the overall length,and the other

35、two at the quarter points of the overall length.11.3 To indicate adequately the conformity to the dimen-sional requirements, measurements shall be taken at randomfrom one bar from each 39 tons 36 tonnes of each lot orfraction thereof.11.4 Insufficient height, insufficient projected area, or ex-cessi

36、ve 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 minimum requirements prescribed inSection 10. No rejection shall be made on the basis ofmeasureme

37、nts if fewer than ten adjacent deformations on eachside of the bar are measured.NOTE 1As used within the intent of 11.3, the term “lot” means all barsof the same nominal weight mass per linear foot metre contained in anindividual shipping release or shipping order.12. Permissible Variation in Size o

38、r Weight Mass12.1 For Type I bars, the permissible variation from thenominal diameter specified in Table 1 shall not exceed +0.030,0.010 in. +0.75, 0.25 mm.12.2 For Type II bars, the permissible variation from thenominal weight mass specified in Table 2 shall not exceed+3 %, 2 %.13. Finish13.1 The b

39、ars shall be free of defects injurious to the tensileproperties and shall have a workmanlike finish.14. Inspection14.1 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 tha

40、t concern the manufacture 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

41、 prior to shipment, unless otherwise specified, andshall be so conducted as not to interfere unnecessarily with theoperation of the works.14.2 If specified in the purchase order, the purchaser shallreserve the right to perform any of the inspection set forth inthe specification where such inspection

42、s are deemed necessaryto assure that the material furnished conforms to prescribedrequirements.15. Rejection and Rehearing15.1 Any rejection based on tests made in accordance with5.2 shall be promptly reported to the manufacturer.15.2 Material that shows injurious defects subsequent to itsacceptance

43、 at the manufacturers facility shall be subject torejection, and the manufacturer shall be notified.15.3 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 r

44、esults of the tests, the manufacturershall be permitted to make claim for a rehearing within thattime.16. Certification16.1 If outside inspection is not required, a manufacturerscertification that the material has been tested in accordancewith and meets the requirements of this specification shall b

45、ethe basis of acceptance of the material. The certification shallinclude theASTM designation, year-date of issue, and revisionletter, if any.16.2 When specified in the purchase order, the manufacturershall furnish a representative load-elongation curve for eachsize and type of bar shipped.16.3 A mod

46、ulus of elasticity value of 29 700 000 psi 205GPa shall be used for the purpose of elongation calculation forType II bars.NOTE 2Experience has shown that load-elongation curves plottedfrom mill tests on Type II bars exhibit variability and are not sufficientlyreliable for use in calculating modulus

47、of elasticity values.16.4 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 o

48、f the EDI transmittedTABLE 3 Deformation Dimensions for Type II BarsNominalDiameterDeformation DimensionsMaximumAverageSpacingMinimumAverageHeightMinimumProjectedAreaAin. mm in. mm in. mm in.2/in. mm2/mm58 15 0.44 11.1 0.03 0.7 0.09 2.434 20 0.52 13.3 0.04 1.0 0.13 3.41 26 0.70 17.8 0.05 1.3 0.17 4.

49、4114 32 0.89 22.5 0.06 1.6 0.21 5.4138 36 0.99 25.1 0.07 1.8 0.24 6.1134 46 1.19 30.1 0.09 2.2 0.29 7.3212 65 1.75 44.5 0.11 2.9 0.38 9.73 75 2.00 50.8 0.13 3.3 0.46 11.7ACalculated from equation, min projected area = 0.75dh/swhere:d = nominal diameter,h = minimum average height, ands = maximum average spacing.A722/A722M 183document shall meet the requirements of the invoked ASTMstandard(s) and conform to any existing EDI agreement be-tween the purchaser and the manufacturer. Notwithstanding theabsence of a signature, the