1、Designation: A 970/A 970M 07Standard Specification forHeaded Steel Bars for Concrete Reinforcement1This standard is issued under the fixed designationA 970/A 970M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of last re
2、vision. 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 deformed and plain steelreinforcing bars in cut lengths, with a head attached to one orboth ends,
3、 for concrete reinforcement. Attachment can beaccomplished through welding, by integrally hot forging of ahead from the reinforcing bar end, by internal threads in thehead mating to threads on the bar end, or by a separate threadednut to secure the head to the bar. Heads are forge formed,machined fr
4、om bar stock, or cut from plate.NOTE 1This specification is applicable for headed bars produced withwelded, threaded, or forged heads and used for reinforcement of concretestructures. The requirements of this specification are not applicable toheaded bars where the attachment of the head is accompli
5、shed by alternatemeans.1.2 This specification is applicable for orders in either SIunits as Specification A 970M or inch-pound units shown inthe text in brackets Specification A 970.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stat
6、ed ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use.
7、 It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A 36/A 36M Specification for Carbon Structural SteelA 370 Test Methods and De
8、finitions for Mechanical Testingof Steel ProductsA 572/A 572M Specification for High-Strength Low-AlloyColumbium-Vanadium Structural SteelA 615/A 615M Specification for Deformed and PlainCarbon-Steel Bars for Concrete ReinforcementA 700 Practices for Packaging, Marking, and LoadingMethods for Steel
9、Products for ShipmentA 706/A 706M Specification for Low-Alloy Steel De-formed and Plain Bars for Concrete Reinforcement2.2 AWS Standards:3AWS C6.1 Recommended Practices for Friction WeldingAWS D1.4/D1.4M Structural Welding Code - ReinforcingSteel2.3 U.S. Military Standard:4MIL-STD-129 Marking for Sh
10、ipment and Storage2.4 U.S. Federal Standard:4Fed. Std. No. 123 Marking for Shipment (Civil Agencies)3. Terminology3.1 Definitions:3.1.1 forged headed barsteel bar used in the reinforce-ment of concrete that has the head(s) integrally forged to one orboth ends.3.1.2 headround, elliptical, or rectangu
11、lar shape used toanchor a steel bar in concrete.3.1.3 threaded headed barsteel bar used in the reinforce-ment of concrete that has the head(s) attached to one or bothends using tapered or straight threads internal to the head or bya separate internally threaded nut securing the head to thethreaded b
12、ar end.3.1.4 welded headed barsteel bar used in the reinforce-ment of concrete that has the head(s) welded to one or bothends.4. Ordering Information4.1 It shall be the responsibility of the purchaser to specifyall requirements that are necessary for material ordered to thisspecification. Such requi
13、rements shall include but are notlimited to the following:1This specification is under the jurisdiction of ASTM A01 on Steel, StainlessSteel and Related Alloys and is the direct responsibility of A01.05 on SteelReinforcement.Current edition approved Oct. 15, 2007. Published October 2007. Originallya
14、pproved in 1997. Last previous edition approved in 2006 as A 970/A 970M06.2For 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
15、ASTM website.3Available from American Welding Society (AWS), 550 NW LeJeune Rd.,Miami, FL 33126, http:/www.aws.org.4Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS. Or visit: http:/assist.daps.dla.mil/online.1*A Summar
16、y 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.4.1.1 Quantity,4.1.2 Name of product: welded, forged, or threaded headedbars for the reinforcement of concrete,4.1.3 Reinforcing
17、bar specification and year of issue,4.1.4 Bar size,4.1.5 Deformed or plain bars,4.1.6 Head geometry, including thickness, height, width,and cross-sectional area,4.1.7 Head material specification and year of issue forwelded head bars (5.2.1),4.1.8 Bend testing of welded headed bars in sizes No. 36,43
18、, and 57 11, 14, and 18 (6.4.1),4.1.9 Number of heads per bar length,4.1.10 Length of bar assembly,4.1.11 Packaging, and4.1.12 ASTM designation and year of issue.5. Material and Manufacture5.1 Reinforcing BarsFor welded headed bars, the rein-forcing bars shall conform to SpecificationA 706/A 706M. F
19、orforged headed bars or threaded headed bars, the reinforcingbars shall conform to Specification A 615/A 615M or A 706/A 706M, as specified by the purchaser.5.2 Heads:5.2.1 For welded and threaded headed bars, the head mate-rial shall be selected by the manufacturer.5.3 The head dimensions shall be
20、provided by the purchaserin the order. Head dimensions shall define the head geometryincluding thickness, height, and width of the head (Fig. 1).Alternate head dimensions supplied by the manufacturer shallbe permitted if agreed to in advance by the purchaser. Themanufacturer shall furnish documentat
21、ion to the purchaser, inthe form of calculations or test reports, or both, that confirmsthe suitability of alternate head dimensions for the intendedapplication.5.4 WeldingA welding procedure conforming to AWSD1.4/D1.4M shall be used for all required production weldingof the head to the bar, except
22、for friction welding that shallconform to AWS C6.1 in conjunction with the manufacturersQA/QC procedures.5.5 ForgingFor integrally forged headed bars, the headsshall be produced by deforming the bar ends in a hot-forgingprocess.5.6 Threading:5.6.1 Threads on bars shall be either tapered or straight.
23、 Thehead shall either thread onto the bar directly, or it shall be heldon the bar end by a nut and counternut. Thread specificationsand standards shall be selected by the manufacturer unlessotherwise agreed with the purchaser.5.6.2 The out-of-roundness in the rolled reinforcing barshall be evaluated
24、 so that the manufacturers minimum threaddimensions are maintained.5.6.3 It shall be permissible to hot- or cold-roll, or machinecut, threads into the surface of the bar and heads at the optionof the manufacturer.6. Mechanical Test and Performance Requirements6.1 Headed bars shall be subjected to me
25、chanical tests toverify production method and product quality prior to manu-facture. Mechanical testing also shall be performed at intervalsduring production.6.2 Tensile Tests:6.2.1 Tensile testing of the headed bar assembly shall beperformed in accordance with the requirements described inTest Meth
26、ods and Definitions A 370. Failure mode shall bereported as partial or total fracture of the bar, the head, or thehead-to-bar connection.6.2.2 Specimen PreparationTensile test specimens shallbe the full cross-section of the bar with a head attached to oneend of the reinforcing bar. The minimum lengt
27、h of the testspecimen shall be the greater of 250 mm 10 in. or ten timesthe nominal diameter of the bar. The test specimen shall beplaced in the testing machine with the head supported toprevent movement and bending of the head. Provisions shall bemade for clearance between the support and any weld
28、orforming material on the reinforcing bar-to-head connection.The opposite bar end of the bar, without a head attached, shallbe gripped by the testing machine and loaded to failure.6.3 Tensile Requirements:FIG. 1 Headed Reinforcing BarA 970/A 970M 0726.3.1 Tensile PropertiesThe tensile properties of
29、the testspecimen shall conform to one of the following classes:6.3.1.1 Class ADevelop the minimum specified tensilestrength of the reinforcing bar.6.3.1.2 Class BDevelop the minimum specified tensilestrength and the minimum specified elongation of the reinforc-ing bar.NOTE 2Reference Specifications
30、A 615/A 615M and A 706/A 706Mrequirements for minimum reinforcing bar tensile properties. Class A hasbeen introduced for applications that only require the development of theminimum tensile strength of the reinforcing bar. The Class B criteriarequires the head and the head-to-bar connection to meet
31、or exceed theminimum specified tensile strength and the minimum specified elongationrequirements of the reinforcing bar. In the previous criteria, the failure ofthe head or the head-to-bar connection within the attachment region wascause for rejection.6.4 Bend Test Requirements:6.4.1 Only welded hea
32、ded bars in sizes No. 10 to 32 3 to10 shall be subject to bend testing. Bend testing of weldedheaded bars in sizes No. 36, 43, and 57 11, 14, and 18 shallbe subject to agreement between the purchaser and manufac-turer.NOTE 3Serious safety issues may be involved in performing bendtests on welded head
33、ed bars in sizes No. 36, 43, and 57 11, 14, and 18.Thus, 6.4 requires such bend testing to be subject to agreement betweenthe purchaser and manufacturer.6.4.2 ProcedureThe test specimen shall be bent around amandrel of suitable diameter to an angle of at least 90 with noobserved partial or total fra
34、cture of the head, the bar, or thehead-to-bar connection.6.4.3 Bend Test MandrelThe mandrel shall be placed soas to directly bend the welded region. The required mandreldimensions for bend testing are prescribed in Table 1. Thecenterline of the bend test mandrel shall be placed at theintersection of
35、 the reinforcing bar and the weld, as shown inFig. 2.6.4.4 Specimen PreparationBend test specimens shall bethe full cross-section of the bar with a head attached to one endof the reinforcing bar. Where the welded head interferes withplacement of the bend test mandrel, sufficient head materialand any
36、 excess material associated with the welding processshall be removed along one edge of the reinforcing bar toprovide a flat surface on the specimen for the bend mandrel.This preparation shall ensure that the contact point of the bendmandrel is directly at the base of the reinforcing bar diameteras s
37、hown in Fig. 2.7. Frequency of Testing7.1 Number of Tests:7.1.1 Pre-ProductionPrior to production, a testing pro-gram shall be undertaken that includes two bend tests and twotensile tests for welded headed bars, and two tensile tests forforged or threaded headed bars. The tests shall be repeated for
38、each combination of head and bar material specification, gradeor type, and welding, threading, or forging process.7.1.2 ProductionIt shall be permissible to use either thetensile test prescribed in 6.3, or the bend test prescribed in 6.4to verify the production method and product quality. A mini-mum
39、 of two tests shall be conducted during the productionshift or period. One test at the start and one test at the end ofeach 8-h shift or less than 8-h production period or at randomintervals during the production period shall be conducted.7.1.2.1 In the event different heats of head or bar material,
40、or both, within the same material specification are used toproduce welded, threaded, or forged headed bars during aproduction run, a minimum of two tensile tests in accordancewith 6.3 or two bend tests in accordance with 6.4 shall beconducted to verify the production method, product quality,and weld
41、ing, forging, or threading quality or weldability of theheats of materials prior to continuing production.7.2 Retests:7.2.1 Pre-ProductionAny identified procedural or perfor-mance deficiencies shall be corrected and pre-productiontesting repeated until the tensile and bend test results meet theperfo
42、rmance requirements of this specification.7.2.2 ProductionFor welded headed bars, when partial ortotal fracture(s) of the bend or tensile test specimens occur(s)in the weld, the production lot shall be rejected and a retestshall be conducted as shown in 7.2.2.1 or 7.2.2.3. Duringproduction tests of
43、welded, forged, or threaded bars, if anytensile test specimen fails to not meet the requirements fortensile properties in 6.3.1, the production lot shall be retestedas shown in 7.2.2.1. For threaded components used to assemblethe threaded headed bars, if thread dimensions are found not tomeet the ma
44、nufacturers specifications for the thread, theproduction lot shall be rejected.7.2.2.1 If the result of a tension test fails to meet therequirements for tensile properties in 6.3.1, then a retest shallbe allowed. Two specimens taken at random from the produc-tion lot shall be tested during a retest.
45、 Both specimens shallpass the tension test requirements of Section 6, or the produc-tion lot shall be rejected.7.2.2.2 If any test specimen fails because of mechanicalreasons, such as failure of the testing equipment or from flawscaused by specimen preparation, shipment, or other damageunrelated to
46、manufacturing or testing, it shall be discarded andanother specimen from the same production lot substituted.7.2.2.3 If a bend test fails for reasons other than mechanicalreasons or flaws in the specimen, as described in 7.2.2.2,aTABLE 1 Bend Test RequirementsBar Designation Mandrel Diameter10, 13 a
47、nd 16 3, 4 and 5 3dA19, 22 and 25 6, 7 and 8 4d29, 32 and 36 9, 10 and 11 6d43 and 57 14 and 18 8dAd = nominal diameter of barFIG. 2 Bend Test Specimen Mandrel ConfigurationA 970/A 970M 073retest shall be permitted on two random specimens from thesame production lot. If the results of both test spec
48、imens meetthe specified requirements, the lot shall be accepted.8. Finish8.1 Rust, surface irregularities, or mill scale shall not because for rejection, provided the dimensions, cross-sectionalarea, and tensile properties of a hand wire brushed specimenare not less than the requirements of this spe
49、cification.9. Inspection9.1 The inspector representing the purchaser shall have freeentry while work on the contract of the purchaser is beingperformed to the parts of the manufacturers facilities thatconcern manufacture of the material ordered. The manufac-turer shall afford the inspector reasonable access to the facili-ties to satisfy the inspector that the materials and proceduresare in accordance with this specification. Inspection at theplace of manufacture shall be conducted so as not to interfereunnecessarily with the operation
