1、Designation: A 1032 04Standard Test Method forHydrogen Embrittlement Resistance for Steel Wire HardDrawn Used for Prestressing Concrete Pipe1This standard is issued under the fixed designation A 1032; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes procedures to determine thehydrogen embrittlement (HE) resis
3、tance of hard drawn steelwire used for prestressing concrete pipe.1.2 HE resistance is reported as time-to-failure of specimenstested in a laboratory.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does no
4、t purport to address all of thesafety concerns, if any, associated with its use. 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 Standard
5、s:2A 648 Specification for Steel Wire, Hard Drawn for Pre-stressing Concrete PipeD 1193 Specification for Reagent Water3. Summary of Test Method3.1 Characterization of HE resistance of hard-drawn steelwire is accomplished by determining the time-to-failure of awire specimen under a maintained consta
6、nt tensile force, whileimmersed in a heated solution of ammonium thiocyanate(NH4SCN). The load, the solution temperature, and length oftime in the test are continuously monitored.4. Significance and Use4.1 Hard-drawn steel wire as used in prestressing concretepipe may be exposed to elemental hydroge
7、n favorable tohydrogen induced embrittlement and cracking. Resistance tohydrogen embrittlement is necessary for prestressing wire toprovide long-term performance to installed pipe.4.2 The length of time that a stressed wire specimen resistsfailure while exposed to a heated solution of NH4SCN, is ani
8、ndication of the specimens resistance to hydrogen embrittle-ment.5. Apparatus5.1 Test CellThe test cell shall contain the test solutionand the wire specimen and be constructed of material which isinert to NH4SCN (as shown in Fig. 1). The test cell shall becylindrical with an inside diameter sufficie
9、nt to provide aminimum of 5 mL of solution per 100 mm2(2 in.3per in.2)ofwire specimen surface area in contact with the solution. Thetest cell length shall allow the exposure of a minimum testsample length of 150 mm (6 in.) to the test solution. The testcell shall be so designed that the wire specime
10、n passes throughit and is sufficiently exposed outside the end of the cell as toallow application of a tensile force to the specimen.5.2 ChronometerA chronometer with a precision of atleast 6 1 min. and capable of being stopped automatically onfracture of the sample shall be used.5.3 Tensile Force F
11、rameA closed stiff frame, in eitherhorizontal or vertical orientation, shall be employed to positionthe test cell such that a constant tensile force shall be appliedto the test specimen and maintained. The tensile force shall beaccomplished through use of a dead weight, or hydraulicloading system eq
12、uipped with a force indicator.6. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch
13、specifications are available. Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean re
14、agent water as definedby Type 4 of Specification D 1193.1This test method is under the jurisdiction of ASTM Committee A01 on Steel,Standard Steel and Related Alloys and is the direct responsibility of SubcommitteeA01.05 on Steel Reinforcement.Current edition approved Sept. 1, 2004. Published Septemb
15、er 2004.2For 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.1Copyright ASTM International, 100 Barr Harbor Drive,
16、 PO Box C700, West Conshohocken, PA 19428-2959, United States.6.3 Ammonium ThiocyanateNH4SCN solution shall beprepared by dissolving 250 g of NH4SCN (98.5 % pure) per1.0 L (0.52 lb of NH4SCN per 1.0 qt) of water.7. Sampling, Test Specimens, and Test Units7.1 Hard-Drawn Steel WireThe wire shall compl
17、y withSpecification A 648.7.2 A test unit shall consist of 1500 mm (60 in.), or suchlength as specified by the testing laboratory, of wire from a coilof wire. Specimens shall be identified with size, class, rod heatnumber, manufactured wire coil number, and name of wire androd manufacturer.7.2.1 The
18、 mechanical properties shall have been determinedin accordance with applicable sections of Specification A 648and a certified mill test report for the test unit shall be provided.7.3 Test SpecimenA test specimen shall be cut from thewire test unit, of such length that a minimum length of 150 mm(6 in
19、.) will be exposed to the test solution, plus sufficient lengthto connect to a tension loading device. The test specimen shallbe identified as required in 7.2.7.3.1 The test specimen shall be cleaned by wiping with asoft cloth and degreased in acetone, or in trichlorethylene, thendried in air.7.3.2
20、To prevent false negative results, the test specimenmay be coated with an insulating material such as varnish, upto 25 mm (1 in.) into the test cell at each end. The 25 mmlength of coating at each end within the cell shall not beconsidered part of the length required in 7.3.8. Procedure8.1 Preparati
21、onPlace the test specimen into the emptytest cell and seal the ends of the cell. Place the test cell into thetensile force frame.8.2 Load ApplicationApply a tensile force to the wirespecimen until 70 % of the Specification A 648 minimumtensile strength for the wire diameter and class being tested is
22、developed. Maintain the tensile force to within 6 2.0 % for theduration of the test. The tensile load application shall becompleted within 5 min of loading initiation.8.3 Fill Test CellUpon completion of tensile force appli-cation, fill the test cell with NH4SCN test solution, preheated toa temperat
23、ure of 50 6 1C (122 6 2F). Filling of the test cellshall be completed within 1 minute.8.4 Tensile Load and TemperatureThe tensile force andthe solution temperature shall be monitored and maintainedwithin the load requirements of 8.2 and the temperaturerequirements of 8.3, for the duration of the tes
24、t.8.5 Time to FailureWith a full test cell, set the chronom-eter to zero and record time to failure to the nearest 1 min.Terminate test after 100 h of exposure if failure has notoccurred.9. Report9.1 Report ContentsA report of the HE tests for eachspecimen tested shall be made and shall include:9.1.
25、1 Date of test and date of report.9.1.2 Identification of the test specimen.9.1.3 Wire diameter and class.9.1.4 Manufacturer of wire and manufacturer of rod.9.1.5 Wire coil number and rod heat number.9.1.6 Mechanical properties determined in accordance withSpecification A 648.9.1.7 Chemical composit
26、ion in accordance with Specifica-tion A 648.9.1.8 Number of hours-to-failure, or number of hours to testtermination.9.1.9 Description of the actual test fabrication and testingprocedures.10. Precision and Bias10.1 PrecisionNo statement is made on the precision ofthis test method since the test resul
27、ts indicate only whetherthere is conformance to given criteria and no generallyaccepted method for determining precision of this test methodFIG. 1 Test CellA1032042is currently available. General guidelines provided herein forthe specimens, instrumentation, and procedures make theresults intractable
28、 to calculation of meaningful values bystatistical analysis for precision at this time.10.2 BiasSince there is no accepted reference materialsuitable for determining the bias in this test method, nostatement on bias is made.11. Keywords11.1 cracking; hydrogen embrittlement; prestressed con-crete pip
29、e; prestressing; steel wireASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infri
30、ngement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standar
31、d or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your view
32、s 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), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).A1032043
