1、Designation: A 911/A 911M 05Standard Specification forUncoated, Stress-Relieved Steel Bars for PrestressedConcrete Railroad Ties1This standard is issued under the fixed designation A 911/A 911M; the number immediately following the designation indicates the yearof original adoption or, in the case o
2、f revision, the year 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 stress-relieved steelbars for use in prestressed concrete
3、 railroad ties.1.2 Supplement I describes low-relaxation bars and relax-ation testing for that product. Low-relaxation bars shall befurnished when specifically ordered, and may be furnished inplace of regular bars if mutually agreed to by the purchaser andmanufacturer.1.3 This specification is appli
4、cable for orders in eitherinch-pounds units (as Specification A 911) or in SI units (asSpecification A 911M).1.4 The values stated in either inch-pound units or SI unitsare to be regarded separately as standards. Within the text, theSI units are shown in brackets. The values stated in eachsystem are
5、 not exact equivalents; therefore, each system mustbe used independently of the other. Combining values from thetwo systems may result in nonconformance with the specifi-cation.2. Referenced Documents2.1 ASTM Standards:2A 370 Test Methods and Definitions for Mechanical Testingof Steel ProductsE 328
6、Methods for Stress-Relaxation Tests for Materialsand Structures2.2 Federal Standard:Fed. Std. No. 123 Marking for Shipments (Civil Agencies)32.3 Military Standards:MIL-STD-129 Marking for Shipment and Storage3MIL-STD-163 Steel Mill Products Preparation for Ship-ment and Storage33. Terminology3.1 Def
7、initions of Terms Specific to This Standard:3.1.1 lot, nall the coils of bars of the same nominal barsize contained on an individual shipping release or shippingorder, from the same cast or heat of steel.4. Ordering Information4.1 It shall be the responsibility of the purchaser to specifyall require
8、ments that are necessary for bars ordered to thisspecification. Such requirements shall include, but are notlimited to, the following:4.1.1 Quantity (weight) mass,4.1.2 Name of material (uncoated, stress-relieved bars forprestressed concrete railroad ties),4.1.3 Diameter of bar (inches) millimetres,
9、4.1.4 Packaging,4.1.5 ASTM designation and year of issue, and4.1.6 Special requirements, if any.NOTE 1A typical ordering description is as follows: 100 tons 90 tuncoated, stress-relieved steel bars for prestressed concrete railroad ties,0.394-in. 10-mm diameter bars in 6.5-ft 2.0-m diameter coils to
10、 ASTMA XXX A XXXM .5. Manufacture5.1 The bars shall be made from properly identified heats ofsteel made by the electric-furnace, the open-hearth, or the basicoxygen process.5.2 After hot-rolling, the bars shall be cold-drawn andfinally stress-relieved by induction heat treatment to producethe desire
11、d mechanical properties and then coiled.6. Chemical Requirements Chemical Requirements6.1 An analysis of each heat of steel shall be made by themanufacturer from test samples taken during the pouring ofeach heat.6.2 The analysis of the steel shall conform to the chemicalrequirements specified in Tab
12、le 1.1This specification 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 May 1, 2005. Published May 2005. Originallypublished in 1992. Last previous edi
13、tion approved in 2002 as A 911/A 911M 02.2For 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.3Available from Stan
14、dardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.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.7. Mecha
15、nical Requirements7.1 Test MethodTests shall be made in accordance withTest Methods and Definitions A 370, including Annex A4,using full-size bar specimens taken from either end of the coilof the finished product.7.2 Tensile StrengthThe minimum tensile strength of thefinished bar, as represented by
16、test specimens, shall conform tothe requirements prescribed in Table 2.7.3 Yield StrengthYield strength shall be measured at 1 %extension under load. The load at this extension is recorded asyield strength and shall meet the requirements of Table 2.7.4 ElongationThe total elongation after rupture sh
17、all notbe less than 6.0 % and shall be measured in a gage length of 4in. 100 mm.7.5 Wrapping TestBars shall withstand being woundaround a mandrel with a diameter of five times the bar diameterwithout cracking or other surface defects occurring on theoutside of the bent portion. The bar shall be bent
18、 around themandrel 112 turns beginning with a 90 bend.8. Dimensions and Permissible Variations8.1 The size of the finished bar shall be expressed as thenominal diameter of the bar in decimals of an inch millime-ter. The required initial diameters before cold-drawing, andthe final diameters after col
19、d-drawing shall be as follows:Initial Diameter Final Diameter0.591 in. 15 mm 0.370 in. 9.4 mm0.614 in. 15.6 mm 0.394 in. 10 mm0.654 in. 16.6 mm 0.413 in. 10.5 mm8.2 Permissible Variations in Diameter:8.2.1 All bars shall conform to a size tolerance of 60.002in. 60.05 mm from the nominal diameter.8.3
20、 Out of RoundThe difference between the largest andsmallest diameter, measured at the same section, shall not begreater than 0.002 in. 0.04 mm.9. Workmanship, Finish, and Appearance9.1 Joints:9.1.1 There shall be no welds or joints in the finished bar.Any welds or joints made during manufacture to p
21、romotecontinuity of operations shall be removed.9.2 The finished bar shall be uniform in diameter in con-formance with Section 8 and shall be free of imperfections notconsistent with good commercial practice.9.3 StraightnessAfter uncoiling, there shall be no residualout of line deformation greater t
22、han 0.4 in. 10 mm in a lengthof 40 in. 1000 mm.10. Sampling10.1 Test specimens taken from either end of the coil arepermitted. Any specimen found to contain a joint shall bediscarded and a new specimen obtained.11. Number of Tests11.1 One test specimen each for the tensile test and thewrapping test
23、shall be taken for each 10 coils or fractionthereof in a lot.12. Inspection12.1 The purchaser shall be allowed to request that arepresentative inspect or witness the inspection and testing ofthe material prior to shipment. Such agreement shall be madeby the purchaser and manufacturer as part of the
24、purchasecontract.12.2 When such inspection or witness of inspection andtesting is agreed upon, the purchasers representative shall beafforded reasonable access to facilities to assure that thematerial meets the requirements of this specification. Inspec-tion and tests shall be conducted so as to avo
25、id unnecessaryinterference with the manufacturers operations.13. Rejection and Rehearing13.1 Failure of any test specimen to comply with therequirements of this specification shall constitute grounds forrejection of the lot represented by the specimen.13.2 The manufacturer shall be allowed to resubm
26、it the lotfor inspection by testing a sample from each reel and sortingout nonconforming material.13.3 In the event that testing of any individual sampleresults in a reasonable doubt as to the ability of the bar tosatisfy any requirement of this specification, two additionaltests shall be made on sa
27、mples of bar from the same reel, andif failure occurs in either of these tests, the represented coilshall be rejected.14. Certification14.1 In the event that outside inspection is waived, amanufacturers certification that the material has been tested inTABLE 1 Chemical RequirementsElement Compositio
28、n, %Carbon 0.700.90ASilicon 0.100.35Manganese 0.500.90BChromium, max 0.15Phosphorus, max 0.030Sulphur, max 0.035Copper, max 0.30ACarbon in any one lot shall not vary more than 0.13 %.BManganese in any one lot shall not vary more than 0.30 %.TABLE 2 Mechanical RequirementsYield strength, min 200 ksi
29、1375 MPaTensile strength, min 228 ksi 1570 MPaRatio of yield strength to tensile strength, max 0.95Elongation after rupture in a gage length of 4 in.100 mm, min6.0 %Reduction of area, min 30.0 %TABLE 3 Relaxation Requirementsfpi/fpuAMax Stress Losses after 1000 h, %0.50 1.00.60 1.00.70 2.50.80 5.0Af
30、pi= initial prestress load, andfpu= specified minimum tensile strength.A 911/A 911M 052accordance with and meets the requirements of this specifica-tion shall be the basis of acceptance of the material.14.2 The manufacturer shall, when requested in the order,furnish a representative load-elongation
31、curve for each sizeshipped.14.3 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 con
32、tent 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 is responsible for the content o
33、f the report.NOTE 2The industry definition as invoked here is: EDI is thecomputer-to-computer exchange of business information in a standardformat such as ANSI ASC X12.15. Product Marking and Packaging15.1 The bars shall be furnished in coils having a minimumcore diameter of 6.5 ft 2.0 m, for bars o
34、f 0.370 in. 9.4 mmdiameter and a minimum core diameter of 8.0 ft 2.4 m forbars of 0.394 in. 10 mm and 0.413 10.5 mm diameter,unless otherwise specified by the purchaser. Lengths of coilsshall be as agreed upon at the time of purchase. Each coil shallbe identified with two strong tags securely attach
35、ed showingthe length, size, grade, ASTM designation, and the name ormark of the manufacturer.15.2 Low-relaxation bars produced in accordance with therequirements of Supplement I shall be specially identified.15.3 For Government Procurement Only When specifiedin the contract or order, and for direct
36、procurement by or directshipment to the United States government, material shall bepreserved, packaged, and packed in accordance with therequirements of MIL-STD-163. The applicable levels shall beas specified in the contract. Marking for shipment of suchmaterial shall be in accordance with Fed. Std.
37、 No. 123 for useby civil agencies and MIL-STD-129 for use by militaryagencies.16. Transportation and Storage16.1 The bars shall be well-protected using good commer-cial practice against mechanical injury and contamination inshipping as mutually agreed upon by the purchaser andmanufacturer at the tim
38、e of purchase. The coils shall not beexposed to weather during transportation or storage. Storageareas shall be free from aggressive elements such as chlorides,nitrates, fertilizers, acids, or other deleterious materials.Corrosion preventing coatings shall be allowed to be used toafford protection a
39、gainst corrosion, but assurance shall bemade that the corrosion inhibitor can be removed with suitablesolvents by the purchaser. Steel with rust, which can beremoved with a soft, dry rag, shall not be cause for rejection.Steel with pitted rust shall be subject to rejection.17. Keywords17.1 prestress
40、ed concrete; railroad ties; steel bars,stress-relievedSUPPLEMENTARY REQUIREMENTSI. LOW-RELAXATION BARSS1 ScopeS1.1 This supplement delineates only those details that arepeculiar to low-relaxation bars, and to the methods of relax-ation testing related to bars having properties generally asdescribed
41、in Specification A 911/A 911M.S2 Test MethodS2.1 Low-relaxation bars shall be tested as prescribed inMethod E 328.S3 Relaxation PropertiesS3.1 Low-relaxation bars shall meet the mechanical prop-erty requirements of this specification, with the added require-ments listed in Table 3.S4 Yield StrengthS
42、4.1 Yield strength of low-relaxation bars, as described in7.3, shall not be less than 90 % of the specified minimumbreaking strength of the bar.S5 Conditions of Relaxation TestS5.1 If required, relaxation evidence shall be provided fromthe manufacturers records of tests on similarly dimensionedbars.
43、S5.2 The temperature of the test specimen shall be main-tained at 68 6 3.5F 20 6 2C.S5.3 The test specimen shall not be subjected to loadingprior to the relaxation test.S5.4 The initial load shall be applied uniformly over aperiod of not less than 3 min and not more than 5 min, and thegage length sh
44、all be maintained constant; load relaxationreadings shall commence 1 min after application of the totalload.S5.5 Overstressing of the test specimen during the loadingoperation shall not be permitted.S5.6 It is desirable to have a test gage length of at least 60times the nominal diameter. If this gag
45、e length cannot be useddue to limitations in the capacity of the extensometer or testingmachine, a shorter gage length may be used. The minimumallowable gage length is 40 times the nominal diameter.A 911/A 911M 053SUMMARY OF CHANGESCommittee A01 has identified the location of selected changes to thi
46、s standard since the last issue (A 911/A911M99) that may impact the use of this standard.(1) Revised 10.1 to enhance the wording. (2) Revised S5.2, S5.3 and S5.5 for consistency.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item men
47、tionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee
48、 and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meetin
49、g of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone),
