BS ISO 16573-2015 Steel Measurement method for the evaluation of hydrogen embrittlement resistance of high strength steels《钢材 估高强度钢材抗氢脆性的测量方法》.pdf

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1、BSI Standards PublicationBS ISO 16573:2015Steel Measurement methodfor the evaluation of hydrogenembrittlement resistance ofhigh strength steelsBS ISO 16573:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 16573:2015.The UK participation in its preparation w

2、as entrusted to TechnicalCommittee ISE/101/7, Methods of physical and metallographictesting.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible f

3、or its correctapplication. The British Standards Institution 2015. Published by BSI Standards Limited 2015ISBN 978 0 580 79650 0ICS 77.040.99Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy

4、and Strategy Committee on 30 April 2015.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 16573:2015 ISO 2015Steel Measurement method for the evaluation of hydrogen embrittlement resistance of high strength steelsAcier Mthode de mesure pour lvaluation de la rsistance l

5、a fragilisation par lhydrogne des aciers haute rsistanceINTERNATIONAL STANDARDISO16573First edition2015-04-01Reference numberISO 16573:2015(E)BS ISO 16573:2015ISO 16573:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015All rights reserved. Unless otherwise specified, no part

6、 of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member bod

7、y in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 16573:2015ISO 16573:2015(E)Foreword ivIntroduction v1 Scope . 12 Principle 13 Specimen preparation 34

8、 Hydrogen charging methods 34.1 General . 34.2 Cathodic charge method . 34.2.1 Hydrogen charging solution . 34.2.2 Hydrogen charging conditions . 44.3 Hydrogen absorption in aqueous solution at free corrosion potential 44.4 Hydrogen absorption in atmospheric corrosion environments. 44.5 Hydrogen abs

9、orption in high pressure hydrogen gas . 45 Preparation of electroplating solution and electroplating condition . 55.1 General . 55.2 Electroplating solution . 55.3 Electroplating conditions . 56 Constant loading test 56.1 Constant loading test procedures . 56.2 Presentation of the results 67 Post-te

10、st specimen treatment . 88 Hydrogen thermal desorption analysis 88.1 General . 88.2 Experimental apparatus (gas chromatograph) 88.3 Experimental apparatus (mass spectrometry) . 99 Test report . 9Bibliography .10 ISO 2015 All rights reserved iiiContents PageBS ISO 16573:2015ISO 16573:2015(E)ForewordI

11、SO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical c

12、ommittee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electr

13、otechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was dra

14、fted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent ri

15、ghts. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not consti

16、tute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT), see the following URL: Foreword Supplementary information .The com

17、mittee responsible for this document is ISO/TC 17, Steel, Subcommittee SC 7, Methods of testing (other than mechanical tests and chemical analysis).iv ISO 2015 All rights reservedBS ISO 16573:2015ISO 16573:2015(E)IntroductionThe mechanical properties of high strength steels, such as tensile strength

18、, elongation and reduction of area, would be degraded by the effect of hydrogen, known as hydrogen embrittlement, and the susceptibility of hydrogen embrittlement becomes greater with increasing the strength level of steels. This International Standard suggests a standardized test method for the eva

19、luation of hydrogen embrittlement resistance of high strength steels. ISO 2015 All rights reserved vBS ISO 16573:2015BS ISO 16573:2015Steel Measurement method for the evaluation of hydrogen embrittlement resistance of high strength steelsWARNING Persons using this International Standard should be fa

20、miliar with normal laboratory practice. This International Standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory

21、 conditions.1 ScopeThis International Standard provides a method for the evaluation of the resistance to hydrogen embrittlement (i.e. hydrogen delayed fracture) using constant loading test with hydrogen pre-charged specimens. The amount of hydrogen content absorbed in the specimens is analysed quant

22、itatively by thermal desorption analysis such as gas chromatography, mass spectrometry and so on. In the case of hydrogen continuous charging such as hydrogen absorption in aqueous solution at free corrosion potential, hydrogen absorption in atmospheric corrosion environments and hydrogen absorption

23、 in high pressure hydrogen gas, the evaluation method is also briefly described. This method is mainly applicable to the evaluation of hydrogen embrittlement resistance of high strength steel bolts.2 PrincipleThis test method is used to evaluate material resistance to hydrogen embrittlement. Figure

24、1 shows schematic sequences for a) hydrogen pre-charging method and b) hydrogen continuous charging method. For the hydrogen pre-charging method see Figure 1 a), prepare a test specimen which has a higher hydrogen level by forcibly charging hydrogen into the specimen. Apply constant load to the hydr

25、ogen charged test specimen and measure the time to failure. By testing specimens containing various contents of diffusible hydrogen, which is mainly responsible for hydrogen embrittlement, the relationship between diffusible hydrogen content and times to failure can be obtained. Diffusible hydrogen

26、content can be measured by thermal desorption analysis using the test specimen after failure. This method can provide at least qualitative comparison of the resistance to hydrogen embrittlement among several high strength steels having different microstructures or compositions. For the hydrogen cont

27、inuous charging method see Figure 1 b), a test specimen is loaded in one of the following three conditions:a) in aqueous solution at free corrosion potential;b) in atmospheric corrosion environments;c) in high pressure hydrogen gas.INTERNATIONAL STANDARD ISO 16573:2015(E) ISO 2015 All rights reserve

28、d 1BS ISO 16573:2015ISO 16573:2015(E)Then, hydrogen analysis is carried out after failure of the specimen. If specimens do not fail up to 100 h (up to 200 h, if necessary), qualitative comparison of the resistance to hydrogen embrittlement can be made by hydrogen analysis of unbroken specimens.a) Hy

29、drogen pre-charging method b) Hydrogen continuous charging methodFigure 1 Flow chart illustrating the test methods2 ISO 2015 All rights reservedBS ISO 16573:2015ISO 16573:2015(E)3 Specimen preparationThe dimensions of the specimens are shown in Figure 2, and other configurations of the test specimen

30、 may be applied. It is recommended to use specimens of 10 mm in diameter as a standard size. For samples with smaller diameter (i.e. D = 5 mm), r/D = 0,02 may be applied.12a) Notched specimenb) Smooth specimend/D 0,6r/D 0,01 or 0,02Lc/D 7G/D 5Figure 2 Dimensions and shape of specimens4 Hydrogen char

31、ging methods4.1 GeneralThere are four hydrogen charging methods, such as cathodic charging, hydrogen absorption in aqueous solution at free corrosion potential, hydrogen absorption in atmospheric corrosion environments and hydrogen absorption in high pressure hydrogen gas. The examples of the condit

32、ion of each method are as follows.4.2 Cathodic charge method4.2.1 Hydrogen charging solutionTo estimate the effect of hydrogen on the mechanical properties of steels, the hydrogen is forced to diffuse into the specimens by the cathodic charging method. For hydrogen pre-charging, the charging solutio

33、n should be prepared and the chemical compositions of the solutions are listed in Table 1.Two kinds of solutions may be used for hydrogen pre-charging. Solution 1 may be used for introducing a relatively large amount of hydrogen to the specimens and Solution 2 may be used for introducing a small amo

34、unt of hydrogen. ISO 2015 All rights reserved 3BS ISO 16573:2015ISO 16573:2015(E)Table 1 Chemical composition of the solutions for hydrogen chargingCharging solution ElementContent g /LMarkSolution 1NaCl 30Large amount of hydrogenNH4SCN 3Solution 2 NaOH 4 Small amount of hydrogen4.2.2 Hydrogen charg

35、ing conditionsThe electro-chemical cell for hydrogen pre-charging may be placed in a 200 ml to 1 000 ml beaker. It is recommended that the anode of the electrochemical cell be made of platinum wire of spiral type of 0,5 mm in diameter and 2 m in length (counter electrode), and the specimen works as

36、the cathode (working electrode). After the Pt wire and the specimen are placed in the cell, apply the constant current of its current density in the range of 0 A/m220 A/m2by using potentio/galvanostat for 48 h. A charging time of 48 h is recommended, but other charging times are also optional as lon

37、g as a total time of 72 h is reached for hydrogen charging and the homogenization treatment by room temperature exposure after cadmium (Cd) plating. For materials with low hydrogen diffusion coefficient, the hydrogen charging time and the total time may be increased. The specimens surface area shoul

38、d be calculated for proper current supply. The pre-charged hydrogen amount may be changed by varying the current density or pre-charging time. However, it is recommended to use fixed pre-charging time and current density to get reproducible test results.4.3 Hydrogen absorption in aqueous solution at

39、 free corrosion potentialFor hydrogen charging by corrosion in acid, HCl solutions or HCl with CH3COOH/CH3COONa buffered solutions are often used. For example, specimen shall be immersed in 5 % HCl solution at room temperature. Immersion time shall be determined based on the specimen size and hydrog

40、en diffusion coefficient of the tested material.4.4 Hydrogen absorption in atmospheric corrosion environmentsFor hydrogen charging by atmospheric corrosion, the salt spray test (SST) or cyclic corrosion tests (CCT) including salt spraying, drying and humidifying are carried out. As an example, desir

41、able CCT processes are listed in Table 2.Table 2 Example of CCT processesProcess Conditions TimeSalt spray 5 % NaCl, 35 C 2 hDry 20 % to 30 % humidity, 60 C 4 hWet 95 % humidity, 50 C 2 h4.5 Hydrogen absorption in high pressure hydrogen gasFor hydrogen charging by hydrogen gas, the specimens shall b

42、e exposed directly to gaseous hydrogen up to 140 MPa at above room temperature. Exposure time shall be determined based on the specimen size and hydrogen diffusion coefficient of the tested material. However, extreme care is necessary and it is not recommended due to the danger of experiment.4 ISO 2

43、015 All rights reservedBS ISO 16573:2015ISO 16573:2015(E)5 Preparation of electroplating solution and electroplating condition5.1 GeneralThe plating process is applied for the hydrogen pre-charging method in order to prevent hydrogen release during the loading test.5.2 Electroplating solutionAfter h

44、ydrogen pre-charging, Cd plating should be conducted to prevent the release of hydrogen from the specimens during constant loading test. Cd is a well-known toxic material but the hydrogen diffusivity in Cd is known to be nearly zero. Instead of using toxic Cd, other appropriate plating materials, fo

45、r example Zn, may be applied. The elements for Cd plating solution and the amounts of each element are listed in Table 3. The pH of the solution should be 3 pH to 5 pH. To adjust the pH of the solution, one can add H3BO4or ammonium solution. (Please make reference to the recommended Zn plating solut

46、ion in Table 3).Table 3 Elements for Cd and Zn plating solutions and the amounts of each elementSolution Element Type AmountCd plating solutionCd(BF4)2solution (C) = 50 % 427 gNH4BF4solute 48 gH3BO4solute 21,6 gH2O (distilled) solvent 460 mlpH - 3 to 5Zn plating solutionZnCl2solute 45 gKCl solute 23

47、4 gH3BO4solute 21,6 gSodium Dodecyl Sulfate solute 0,5 gH2O (distilled) solvent 700 mlpH - 5 to 65.3 Electroplating conditionsAn electrochemical reaction is used for Cd plating. Immerse the metal platinum (Pt) anode into the prepared Cd solution, and immerse the specimen in order for it to work as a

48、 cathode. After hydrogen pre-charging, clean the specimens by mechanical grinding (polishing) or with 0,1 N HCl and 0,1 N NaOH by ultrasonic cleaner for 30 s, respectively. Then, immerse the specimens in Cd plating solution and apply a constant current of 0,5A for 300 s. Other conditions of current

49、and time may also be used for Cd plating. Using the potential difference, Cd is adhered to the surface of the specimen.The thickness of Cd plating should be at least 15 m or higher to prevent hydrogen release. Extreme care is needed to handle the solutions containing Cd during the entire Cd plating procedures.6 Constant loading test6.1 Constant loading test proceduresThe suggested methods for the constant loading test are the following.a) Use adequate jig to apply uniaxial loading to the specimens. ISO 2015