1、Designation: A911/A911M 11A911/A911M 15Standard Specification forUncoated, Stress-Relieved Low-Relaxation Steel Bars forPrestressed Concrete Railroad Ties1This standard is issued under the fixed designation A911/A911M; the number immediately following the designation indicates the yearof original ad
2、option or, in the case 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 stress-relieved low-relaxation ste
3、el bars for use in prestressed concrete railroad ties.1.2 A supplementary requirement (S1) is provided for use where low-relaxation bars and relaxation testing for that product isrequired by the purchaser. The supplementary requirement applies only when specified in the purchase order or contract.1.
4、2 This specification is applicable for orders in either inch-pounds units (as Specification A911) or in SI units (as SpecificationA911M).1.3 The values stated in either inch-pound units or SI units are to be regarded separately as standards.standard. Within the text,the SI units are shown in bracket
5、s. The values stated in each system aremay not be exact equivalents; therefore, each systemmustshall be used independently of the other. Combining values from the two systems may result in nonconformancenon-conformance with the specification.2. Referenced Documents2.1 ASTM Standards:2A370 Test Metho
6、ds and Definitions for Mechanical Testing of Steel ProductsE328 Test Methods for Stress Relaxation for Materials and Structures2.2 Federal Standard:3Fed. Std. No. 123 Marking for Shipments (Civil Agencies)2.3 Military Standards:3MIL-STD-129 Marking for Shipment and Storage3. Terminology3.1 Definitio
7、nsDefinition of TermsTerm Specific to This Standard:Specification:3.1.1 lot, nall the coils of bars of the same nominal bar size contained on an individual shipping release or shipping order,from the same heat of steel.4. Ordering Information4.1 It shall be the responsibility of the purchaser to spe
8、cify all requirements that are necessary for bars ordered to thisspecification. Such requirements shall include, but are not limited to, the following:Orders for low-relaxation steel bars forprestressed concrete railroad ties under this specification shall contain the following information:4.1.1 Qua
9、ntity (weight) mass,4.1.2 Name of material (uncoated, stress-relieved bars for prestressed concrete railroad ties),4.1.2 Nominal diameter of bar (inches) millimetres,4.1.4 Inspection (Section 12),4.1.5 Load-elongation curve (14.2),4.1.3 Core diameter and length of coils (15.1),1 This specification i
10、s under the jurisdiction ofASTM Committee A01 on Steel, Stainless Steel and RelatedAlloys and is the direct responsibility of Subcommittee A01.05on Steel Reinforcement.Current edition approved Jan. 15, 2011Nov. 1, 2015. Published February 2011January 2016. Originally published in 1992. Last previous
11、 edition approved in 20052011as A911/A911M 05.A911/A911M 11. DOI: 10.1520/A0911_A0911M-11.10.1520/A0911_A0911M-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the
12、 standards Document Summary page on the ASTM website.3 Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.This document is not an ASTM standard and is intended only to provide the user of an ASTM s
13、tandard 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 consult prior editions as appropriate. In all cases only the current versionof the standard as published by
14、ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.1.4 Packaging,4.1.5 Supplementary Requirement S1 (if desired), and4.1.6
15、ASTM designation (A911 A911M) and year of issue.4.2 The purchaser shall have the option to specify additional requirements, including but not limited to, the following:4.2.1 Prior relaxation tests of similarly-dimensioned bars (7.6.3),4.2.2 Inspection and witnessing of testing (Section 12),4.2.3 Loa
16、d-elongation curves for each test (14.2),4.2.4 Special packaging and marking (Section 15), and4.2.5 Other special requirements, if any.5. Manufacture5.1 The bars shall be made from properly identified heats of steel made by the electric-furnace, the open-hearth, or thebasic-oxygen basic-oxygen, or o
17、ther commercially accepted steelmaking process.5.2 After hot-rolling, the bars shall be cold-drawn and finally stress-relieved by induction heat treatment to produce the desiredmechanical properties and then coiled.6. Chemical Requirements6.1 An analysis of each heat of steel shall be made by the ma
18、nufacturer from test samples taken during the pouring of each heat.6.2 The analysis of the steel shall conform to the chemical requirements specified in Table 1.7. Mechanical Property Requirements7.1 Test MethodTests shall be made in accordance with Test Methods and Definitions A370, including Annex
19、 A4, usingfull-size bar specimens taken from either end of the coil of the finished product.7.2 Tensile StrengthThe minimum tensile strength of the finished bar, as represented by test specimens, shall conform to therequirements prescribed in Table 2.7.3 Yield StrengthYield strength shall be measure
20、d at 1 % extension under load. The load at this extension is recorded as yieldstrength and shall meet the requirements of Table 2.7.4 ElongationThe total elongation after rupture shall not be less than 6.0 % and shall be measured in a gage length of 4 in.100 mm.7.5 Wrapping TestBars shall withstand
21、being wound around a mandrel with a diameter of five times the bar diameter withoutcracking or other surface defects occurring on the outside of the bent portion. The bar shall be bent around the mandrel 1-12 turnsbeginning with a 90 bend.7.6 Low-Relaxation TextBars shall be tested as prescribed in
22、Test Methods E328.7.6.1 Low-relaxation bars shall meet the mechanical property requirements of this specification, with the added requirementslisted in Table 3.7.6.2 Yield strength of low-relaxation bars, as described in 7.3, shall not be less than 90 % of the specified minimum tensilestrength of th
23、e bar.7.6.3 If required in the purchase order, relaxation evidence shall be provided from the manufacturers records of tests onsimilarly dimensioned bars.7.6.4 The test specimen shall not be subjected to loading prior to the relaxation test. The temperature of the test specimen shallbe maintained at
24、 68 6 3.5F 20 6 2C. The test gage length shall be at least 40 times the nominal diameter.7.6.5 The initial load shall be applied uniformly over a period of not less than 3 minutes and not more than 5 minutes, and thegage length shall be maintained constant; load-relaxation readings shall commence 1
25、minute after application of the total load.TABLE 1 Chemical RequirementsElement Composition, %Carbon 0.700.90ASilicon 0.100.35Manganese 0.500.90BChromium, max 0.15Phosphorus, max 0.030Sulphur, max 0.035Copper, max 0.30A Carbon in any one lot shall not vary more than 0.13 %.B Manganese in any one lot
26、 shall not vary more than 0.30 %.A911/A911M 1527.6.6 Overstressing of the test specimen by application of loads beyond the limits stated in Table 3 during the loading operationshall not be permitted.8. Dimensions and Permissible Variations8.1 The size of the finished bar shall be expressed as the no
27、minal diameter of the bar in decimals of an inch millimetre. Therequired initial diameters before cold-drawing, and the final diameters after cold-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. 1
28、0.5 mm8.2 Permissible Variations in Diameter:8.2.1 All bars shall conform to a size tolerance of 60.002 in. 60.05 mm from the nominal diameter.8.3 Out-of-RoundThe difference between the largest and smallest diameter, measured at the same section, shall not be greaterthan 0.002 in. 0.05 mm.9. Workman
29、ship, 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 promote continuityof operations shall be removed.9.2 The finished bar shall be uniform in diameter in conformance with Section 8 and shall be free of imp
30、erfections not consistentwith good commercial practice.9.3 StraightnessAfter uncoiling, there shall be no residual out-of-line deformation greater than 0.4 in. 10 mm in a lengthof 40 in. 1000 mm.10. Sampling10.1 Test specimens taken from either end of the coil are permitted.11. Number of Tests11.1 O
31、ne test specimen each for the tensile test and the wrapping test shall be taken for each 10 coils or fraction thereof in alot.12. Inspection12.1 The purchaser shall be allowed to request that a representative inspect or witness the inspection and testing of the materialprior to shipment. Such agreem
32、ent shall be made by the purchaser and manufacturer as part of the purchase order or contract.12.2 When such inspection or witness of inspection and testing is agreed upon, the purchasers representative shall be affordedreasonable access to facilities to assure that the material meets the requiremen
33、ts of this specification. Inspection and tests shall beconducted so as to avoid unnecessary interference with the manufacturers operations.13. Rejection and Rehearing13.1 Failure of any test specimen to comply with the requirements of this specification shall constitute grounds for rejection ofthe l
34、ot represented by the specimen.TABLE 2 Mechanical RequirementsYield strength, min 200 ksi 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 S1.13 Rela
35、xation Requirementsfpi/fpu A Max Stress Losses after 1000 h, %0.50 1.00.60 1.00.70 2.50.80 5.0A fpi = initial prestress load, andfpu = specified minimum tensile strength.A911/A911M 15313.2 The manufacturer shall be allowed to resubmit the lot for inspection by testing a specimen from each coil and s
36、orting outnonconforming material.13.3 In the event that testing of any individual specimen results in a reasonable doubt as to the ability of the bar to satisfy anyrequirement of this specification, two additional tests shall be made on specimens of bar from the same coil, and if failure occursin ei
37、ther of these tests, the represented coil shall be rejected.14. Certification14.1 In the event that If outside inspection is waived, not required, a manufacturers certification that the material has beentested in accordance with and meets the requirements of this specification shall be the basis of
38、acceptance of the material.14.2 The manufacturer shall, when requested in the order, furnish a representative load-elongation curve for each size of barshipped.14.3 A material test report, certificate of inspection,Material Test Report, Certificate of Inspection, or similar document printedfrom or u
39、sed in electronic form from an electronic data interchange (EDI) transmission shall be regarded as having the samevalidity as a counterpart printed in the certifiers facility. The content of the EDI transmitted document mustshall meet therequirements of the invoked ASTM standard(s) and conform to an
40、y existing EDI agreement between the purchaser and thesupplier.manufacturer. Notwithstanding the absence of a signature, the organization submitting the EDI transmission is responsiblefor the content of the report.NOTE 1The industry definition as invoked here is: EDI is the computer-to-computer exch
41、ange of business information in a standard format such asANSI ASC X12.15. Product Marking and Packaging15.1 The bars shall be furnished in coils having a minimum core diameter of 6.5 ft 2.0 m, for bars of 0.370 in. 9.4 mmdiameter and a minimum core diameter of 8.0 ft 2.4 m for bars of 0.394 in. 10 m
42、m and 0.413 10.5 mm diameter, unlessotherwise specified by the purchaser. Lengths of coils shall be as agreed upon at the time of purchase. Each coil shall be identifiedwith two durable tags securely attached showing the length, size, grade, ASTM designation, heat identification number, and thename
43、of the manufacturer.15.2 Low-relaxation bars produced in accordance with the requirements of supplementary requirement (S1) shall be speciallyidentified.15.2 When specified in the purchase order or contract, and for direct procurement by or direct shipment to the U. S.government,Government, marking
44、for shipment, in addition to requirements specified in the purchase order or contract, shall bein accordance with Fed. Std. No. 123 for use by civil agencies and MIL-STD-129 for use by military agencies.16. Transportation and Storage16.1 The bars shall be well-protected using good commercial practic
45、e against mechanical injury and contamination in shippingas mutually agreed upon by the purchaser and manufacturer at the time of purchase. The coils shall not be exposed to weatherduring transportation or storage. Storage areas shall be free from aggressive elements such as chlorides, nitrates, fer
46、tilizers, acids,or other deleterious materials.16.2 Corrosion-preventing coatings shall be allowed to be used to afford protection against corrosion, but assurance shall bemade that the corrosion inhibitor can be removed with suitable solvents by the purchaser. Steel with rust, which can be removedw
47、ith a soft, dry cloth, shall not be cause for rejection. Steel with pitted rust shall be subject to rejection.17. Keywords17.1 low-relaxation bars; prestressed concrete; railroad ties; steel bars, stress-relievedA911/A911M 154SUPPLEMENTARY REQUIREMENTSS1. LOW-RELAXATION BARS AND RELAXATION TESTINGTh
48、e following supplementary requirement shall apply only when specified in the purchase order orcontract.S1.1 ScopeS1.1.1 This supplementary requirement delineates only those details that are peculiar to low-relaxation bars, and to the methodsof relaxation testing related to bars having properties gen
49、erally as described in Specification A911/A911M.S1.2 Test MethodS.1.2.1 Low-relaxation bars shall be tested as prescribed in Test Methods E328.S1.3 Relaxation PropertiesS1.3.1 Low-relaxation bars shall meet the mechanical property requirements of this specification, with the added requirementslisted in Table S1.1.S1.4 Yield StrengthS1.4.1 Yield strength of low-relaxation bars, as described in 7.3, shall not be less than 90 % of the specified minimum tensilestrength of the bar.S1.5 Conditions of Relaxation
