1、Designation:A722/A722M07 Designation: A722/A722M 12Standard Specification forUncoated High-Strength Steel Bars for PrestressingConcrete1This standard is issued under the fixed designation A722/A722M; the number immediately following the designation indicates the yearof original adoption or, in the c
2、ase 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.1. Scope*1.1 This specification covers uncoated high-strength steel bars intended for use in pretensi
3、oned and post-tensioned prestressedconcrete construction or in prestressed ground anchors. Bars are of a minimum ultimate tensile strength level of 1035 MPa(150 000 psi).1.2 Two types of bars are provided: Type I bar has a plain surface and Type II bar has surface deformations.1.3 Supplementary requ
4、irements of an optional nature are provided. They shall apply only when specified by the purchaser.1.4The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.4 The values stated in either SI units or inch-pound units are to be rega
5、rded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance with the specification.2. Referenced Documents2.1 ASTM Standards:2A370 Test M
6、ethods and Definitions for Mechanical Testing of Steel ProductsA700 Practices for Packaging, Marking, and Loading Methods for Steel Products for ShipmentE30 Test Methods for Chemical Analysis of Steel, Cast Iron, Open-Hearth Iron, and Wrought Iron2.2 Government Standards:3MIL-STD-129 Marking for Shi
7、pment and Storage2.3 U.S. Federal Standards:3Fed. Std. 123 Marking for Shipment (Civil Agencies)3. Ordering Information3.1 Orders for material under this specification should include the following information:3.1.1 Quantity,3.1.2 Name of material (uncoated high-strength bars for prestressing concret
8、e),3.1.3 ASTM designation and year of issue,3.1.4 Size and length,3.1.5 Type,3.1.6 Special inspection requirements, if desired (see Section 12),3.1.7 Special preparation for delivery, if desired (see Section 11),3.1.8Load-elongation3.1.8 Load-elongation curve, if required (see Section 15), and3.1.9
9、Supplementary requirements, if desired.NOTE 1A typical ordering description is as follows: 50 uncoated high-strength steel bars for prestressing concrete to ASTM A722/A722M _; 26mm diameter, 12.20 m long, Type II; packed in accordance with A700; meeting supplementary bending properties.1This specifi
10、cation 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 March 1, 2007. Published March 2007. Originally approved in 1975. Last previous edition approved in 2
11、005 as A722/A722M 06. DOI:10.1520/A0722_A0722M-07.Current edition approved May 1, 2012. Published May 2012. Originally approved in 1975. Last previous edition approved in 2007 as A722/A722M 07. DOI:10.1520/A0722_A0722M-12.2For referencedASTM standards, visit theASTM website, www.astm.org, or contact
12、ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer 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 19111-5098, http:/www.d
13、odssp.daps.mil.1This 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 adequately depict all changes accurately, ASTM recommends that users c
14、onsult 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 standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohoc
15、ken, PA 19428-2959, United States.4. Materials and Manufacture4.1 The bars shall be rolled from properly identified heats of ingot cast or strand cast steel. The standard sizes and dimensionsof Type I and II bars shall be those listed in Table 1 and Table 2, respectively.4.2 The bars shall be subjec
16、ted to cold-stressing to not less than 80 % of the minimum ultimate strength, and then shall bestress-relieved, to produce the prescribed mechanical properties.5. Chemical Composition5.1 An analysis of each heat of steel shall be made by the manufacturer from test samples taken during the pouring of
17、 each heat.5.1.1 Choice and use of chemical composition and alloying elements, to produce the mechanical properties of the finished barprescribed 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 not exceed the followin
18、g:Phosphorus 0.040 %Sulfur 0.050 %5.2 A product analysis may be made by the purchaser from the finished bar representing each cast or heat of steel. Thephosphorus and sulfur contents thus determined shall not exceed the limits specified in 5.1.2 by 0.008 %.5.3 Test Methods E30 shall be used for refe
19、ree purposes.6. Mechanical Properties6.1 All testing for mechanical properties shall be performed in accordance with the requirements of Test Methods andDefinitions A370.6.2 Tensile Properties:6.2.1 Finished bars shall have a minimum ultimate tensile strength of 1035 MPa (150 000 psi).6.2.2 The mini
20、mum yield strength of Type I and Type II bars shall be 85 % and 80 %, respectively, of the minimum ultimatetensile strength of the bars. The yield strength shall be determined by either of the methods described in Test Methods andDefinitions A370; however, in the extension under load method, the tot
21、al strain shall be 0.7 %, and in the offset method the offsetshall be 0.2 %.6.2.3 The minimum elongation after rupture shall be 4.0 % in a gage length equal to 20 bar diameters, or 7.0 % in a gage lengthequal to 10 bar diameters.6.3 Test SpecimensTension tests shall be made using full-size bar test
22、specimens. Machined reduced section test specimensare not permitted. All unit stress determinations shall be based on the nominal area shown in Table 1 or the effective area shownin Table 2.6.4 Number of TestsThe number of tensile specimens tested shall be one from each 36 Mg (39 tons) or fraction t
23、hereof, ofeach size of bar rolled from each heat but not less than two from each heat. The specimens shall be randomly selected followingthe final processing operation.6.5 Retests:6.5.1 If any tensile property of any tension test specimen is less than that specified, and any part of the fracture is
24、outside themiddle third of the gage length, as indicated by scribe scratches marked on the specimen before testing, a retest shall be allowed.6.5.2 If the results of an original tension test fail to meet specified requirements, two additional tests shall be made on samplesof bar from the same heat a
25、nd bar size, and if failure occurs in either of these tests, the bar size from that heat shall be rejected.6.5.3 If any test specimen fails because of mechanical reasons such as failure of testing equipment, it shall be discarded andanother specimen taken.6.5.4 If any test specimen develops flaws, i
26、t shall be discarded and another specimen of the same size bar from the same heatsubstituted.7. Requirements for Deformations7.1 Material furnished as Type II bar shall have deformations spaced uniformly along the length of the bar. The deformationson opposite sides of the bar shall be similar in si
27、ze and shape. The average spacing or distance between deformations on both sidesof the bar shall not exceed seven tenths of the nominal diameter of the bar.TABLE 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 0.44227
28、8 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 1.2335 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.A722/A722M 1227.2 The minimum height and minimum
29、projected area of the deformations shall conform to the requirements shown in Table3.7.3 Mechanical CouplingFor those bars having deformations arranged in a manner to permit coupling of the bars with ascrew-on type coupler, it shall be the responsibility of the finished-bar manufacturer to demonstra
30、te that a bar cut at any point alongits length may be coupled to any other length of bar and that a coupled joint supports the minimum specified ultimate tensilestrength of the coupled bars. The coupler type shall be provided or designed by the finished-bar manufacturer.8. Measurements of Deformatio
31、ns8.1 The average spacing of deformations shall be determined by dividing a measured length of the bar specimen by the numberof individual deformations and fractional parts of deformations on any one side of the bar specimen. A measured length of the barspecimen shall be considered the distance from
32、 a point on a deformation to a corresponding point on any other deformation onthe same side of the bar.8.2 The average height of deformations shall be determined from measurements made on not less than two typical deformations.Determinations shall be based on three measurements per deformation: one
33、at the center of the overall length, and the other twoat the quarter points of the overall length.8.3 To indicate adequately the conformity to the dimensional requirements, measurements shall be taken at random from onebar from each 30 Mg (33 tons) of each lot or fraction thereof.8.4 Insufficient he
34、ight, insufficient projected area, or excessive spacing of deformations shall not constitute cause for rejectionunless it has been clearly established by determinations on each lot that typical deformation height or spacing does not conformto the minimum requirements prescribed in Section 7. No reje
35、ction shall be made on the basis of measurements if fewer than tenadjacent deformations on each side of the 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 shipping release orshipping order.9. Permissible
36、Variation in Size or Weight9.1 For Type I bars, the permissible variation from the nominal diameter specified in Table 1 shall not exceed +0.75, 0.25 mm(+0.030, 0.010 in.).TABLE 2 Dimensions for Type II (Deformed) BarNominal DiameterANominal Mass (Weight) Nominal AreaBmm in. kg/m lb/ft mm2in.21558 1
37、.46 0.98 181 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 5.1675 3 35.85 24.09 4419 6.85ANominal diameters are for identification only. Values have been converted frommetric to inch-pound units
38、.BThe nominal area is determined from 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
39、 0.44 0.7 0.03 2.4 0.092034 13.3 0.52 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 0.3875 3 50.8 2.00 3.3 0.13 11.7 0.46ACalculated from equation, min projected are
40、a = 0.75pdh/swhere:d = nominal diameter,h = minimum average height, ands = maximum average spacing.A722/A722M 1239.2 For Type II bars, the permissible variation from the nominal weight specified in Table 2 shall not exceed +3 %, 2 %.10. Finish10.1 The bars shall be free of defects injurious to the m
41、echanical properties and shall have a workmanlike finish.11. Packaging and Package Marking11.1 Packaging, marking, and loading for shipment shall be in accordance with Practices A700.11.2 When specified in the contract or order, and for direct procurement by or direct shipment to the U.S. government
42、, markingfor shipment, in addition to requirements specified in the contract or order, shall be in accordance with MIL-STD-129 for militaryagencies and with Fed. Std. 123 for civil agencies.11.3 Unless otherwise specified in the contract or order, bars shall be grouped by size. Each bundle or lift s
43、hall be taggedshowing the heat number, bar size, specification number (Specification A722/A722M), and the identity of the finished barmanufacturer. The tags shall display the following statement “High Strength Prestressing Bars”. Both ends of each bar shall bepainted yellow.12. Inspection12.1 The in
44、spector representing the purchaser shall have free entry, at all times while work on the contract of the purchaser isbeing performed, to all parts of the manufacturers works that concern the manufacture of the material ordered. The manufacturershall afford the inspector all reasonable facilities to
45、satisfy him that the material is being furnished in accordance with thisspecification.All tests (except product analysis) and inspection, shall be made at the place of manufacture prior to shipment, unlessotherwise specified, and shall be so conducted as not to interfere unnecessarily with the opera
46、tion of the works.12.2 If specified in the purchase order, the purchaser shall reserve the right to perform any of the inspection set forth in thespecification where such inspections are deemed necessary to assure that the material furnished conforms to prescribedrequirements.12.3 If outside inspect
47、ion is waived, the finished-bar manufacturers certification that the material has been tested in accordancewith, and meets the requirements of, this specification, shall be the basis of acceptance of the material.13. Rejection13.1 Unless otherwise specified, any rejection based on tests made in acco
48、rdance with 5.2 shall be reported to the manufacturerwithin 5 working days from the receipt of samples by the purchaser.13.2 Material that shows injurious defects subsequent to its acceptance at the manufacturers works shall be subject to rejection,and the manufacturer shall be notified.14. Rehearin
49、g14.1 Samples tested in accordance with 5.2 that represent rejected material shall be preserved for two weeks from the daterejection is reported to the manufacturer. In case of dissatisfaction with the results of the tests, the manufacturer shall be permittedto make claim for a rehearing within that time.15. Certification15.1 If outside inspection is waived, a manufacturers certification that the material has been tested in accordance with andmeets the requirements of this specification shall be the basis of acceptance of the material. The certif
