1、DRAFT FOR DEVELOPMENTDD CEN ISO/TS 21432:2005Incorporating corrigendum January 2008Non-destructive testing Standard test method for determining residual stresses by neutron diffractionICS 19.100g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38
2、g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58DD CEN ISO/TS 21432:2005This Draft for Development, was published under the authority of the Standards Policy and Strategy Committee on 13 February 2006 BSI 2008ISBN 978 0 580 61856 7National forewordThis D
3、raft for Development is the UK implementation of CEN ISO/TS 21432:2005. It is identical with ISO/TS 21432:2005, incorporating corrigendum January 2008. The start and finish of text introduced or altered by corrigendum is indicated in the text by tags. Text altered by ISO corrigendum January 2008 is
4、indicated in the text by .This publication is not to be regarded as a British Standard.It is being issued in the Draft for Development series of publications and is of a provisional nature because there is limited experience in the application of this method. It should be applied on this provisional
5、 basis, so that information and experience of its practical application may be obtained.Comments arising from the use of this Draft for Development are requested so that UK experience can be reported to the European organization responsible for its conversion to a European standard. A review of this
6、 publication will be initiated 2 years after its publication by the European organization so that a decision can be taken on its status at the end of its 3-year life. Notification of the start of the review period will be made in an announcement in the appropriate issue of Update Standards.According
7、 to the replies received by the end of the review period, the responsible BSI Committee will decide whether to support the conversion into a European Standard, to extend the life of the Technical Specification or to withdraw it. Comments should be sent in writing to the Secretary of BSI Technical Co
8、mmittee WEE/46, Non-destructive testing, at British Standards House, 389 Chiswick High Road, London W4 4AL, giving the document reference and clause number and proposing, where possible, an appropriate revision of the text.A list of organizations represented on this committee can be obtained on requ
9、est to its secretary.Amendments/corrigenda issued since publicationDate Comments30 June 2008 Implentation of ISO corrigendum January 2008.DD CEN ISO/TS 21432:2005 BSI 2008iTextual errorsThe textual errors set out below were discovered when the English language version of DD CEN ISO/TS 21432:2005 was
10、 adopted as the national Draft for Development. They have been reported to ISO in a proposal to amend the text of the international TS.page 10: Figure 3 Key, axis label X erroneously given as 1.page 10: Figure 3 Key, axis label Y erroneously given as 2.page 14: Figure 6 Key, axis label X erroneously
11、 given as 1.page 14: Figure 6 Key, axis label Y erroneously given as 2.page 14: Figure 7 Key, axis label X erroneously given as 1.page 14: Figure 7 Key, axis label Y erroneously given as 2.Please also note that (i) the units for the Y axis (strain) are missing from the Keys to Figures 6 and 7 and sh
12、ould be strain (106) and (ii) the axes labels for Figure 5 on page 11 are missing and should be for the x axis: d spacing (nm) and for the y axis: counts.NOTE Some of the above textual errors have now been implemented as part of ISO corrigendum January 2008.This publication does not purport to inclu
13、de all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a Draft for Development cannot confer immunity from legal obligations.blankTECHNICAL SPECIFICATIONSPCIFICATION TECHNIQUETECHNISCHE SPEZIFIKATIONCEN ISO/TS 21432July 2005ICS 19.100English
14、VersionNon-destructive testing - Standards test method for determiningresidual stresses by neutron diffraction (ISO 21432:2005)Essais non destructifs - Mthode normalise dedtermination des contraintes rsiduelles par diffraction deneutrons (ISO 21432:2005)Zerstrungsfreie Prfung - Standardprfverfahren
15、zurBestimmung von Eigenspannungen durchNeutronenbeugung (ISO 21432:2005)This Technical Specification (CEN/TS) was approved by CEN on 26 March 2005 for provisional application.The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be request
16、ed to submit theircomments, particularly on the question whether the CEN/TS can be converted into a European Standard.CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS availablepromptly at national level in an appropriate form. It i
17、s permissible to keep conflicting national standards in force (in parallel to the CEN/TS)until the final decision about the possible conversion of the CEN/TS into an EN is reached.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, Fr
18、ance,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGMana
19、gement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. CEN ISO/TS 21432:2005: EForeword This document (CEN ISO/TS 21432:2005) has been prepared by Technical Committee CEN/TC 138 “Non-dest
20、ructive testing“, the secretariat of which is held by AFNOR, in collaboration with Technical Committee ISO/TC 135 “Non-destructive testing”. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announce this CEN Technical Spe
21、cification: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. DD CEN ISO/TS 21
22、432:2005iiiContents Page 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 2 4 Symbols and abbreviated terms . 5 4.1 Symbols . 5 4.2 Subscripts . 6 4.3 Abbreviated terms 7 5 Summary of method . 7 5.1 Preamble 7 5.2 Outline of principle Braggs law . 7 5.3 Neutron sources . 7 5.4 Strain
23、measurement . 7 5.5 Neutron diffractometers . 8 5.6 Stress determination 9 6 Preparations for measurements 12 6.1 Preamble 12 6.2 Alignment and calibration of the instrument . 12 6.3 Choice of diffraction conditions 12 6.3.1 Monochromatic instruments . 12 6.3.2 TOF instruments . 15 6.4 Positioning p
24、rocedures 15 6.5 Gauge volumes . 15 6.6 Determination of a strain free or reference lattice spacing 16 7 Material characterization 18 7.1 Preamble 18 7.2 Composition 18 7.3 Thermal/mechanical history 18 7.4 Phases and crystal structures. 18 7.5 Homogeneity . 18 7.6 Microstructure. 18 7.7 Texture . 1
25、8 8 Recording requirements and measurement procedure 19 8.1 Preamble 19 8.2 Recording requirements 19 8.2.1 General information instrument . 19 8.2.2 General information specimen . 20 8.2.3 Specific information required for each strain measurement . 20 8.3 Specimen co-ordinates 21 8.4 Positioning of
26、 the specimen 21 8.5 Measurement directions 21 8.6 Number and location of measuring positions . 21 8.7 Gauge volume . 21 8.8 Gauge volume centroid considerations . 21 8.9 Temperature 22 Introduction v DD CEN ISO/TS 21432:2005iv 9 Calculation of stress. 22 9.1 Preamble 22 9.2 Normal stress determinat
27、ions . 22 9.3 Stress state determinations . 23 9.3.1 The sin2 method . 23 9.4 Choice of elasticity constants . 23 9.5 Data analysis . 24 9.5.1 Peak fitting function 24 9.5.2 Background function 24 9.5.3 Peak to background ratio . 24 9.5.4 Distorted peak profiles . 24 10 Reliability of results 25 11
28、Reporting . 25 11.1 Preamble 25 11.2 Strain or stress values 25 11.2.1 Stress free or reference lattice spacing 26 11.2.2 Conversion of strain to stress . 26 11.2.3 Elasticity constants 26 11.2.4 Positioning. 26 11.3 Neutron source and instrument. 26 11.4 General measurement procedures 26 11.5 Speci
29、mens/materials properties 26 11.6 Original data 27 Annex A (informative) Measurement procedures 28 Annex B (informative) Determination of uncertainties in a measurand 36 Bibliography . 39 DD CEN ISO/TS 21432:2005vIntroduction Neutron diffraction is a non-destructive method that can be employed for d
30、etermining residual stresses in crystalline materials. It can also be used for establishing applied stresses. The procedure can be employed for determining stresses within the interior of materials and adjacent to surfaces. It requires specimens or engineering components to be transported to a neutr
31、on source. Measurements of elastic strain are obtained which are then converted to stress. The purpose of this document is to provide the technical specification for reliably determining stresses that are relevant to engineering applications. DD CEN ISO/TS 21432:2005blank1Non-destructive testing Sta
32、ndard test method for determining residual stresses by neutron diffraction WARNING This Technical Specification does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this Technical Specification to establish appropriate safety and h
33、ealth practices and determine the applicability of regulatory limitations prior to use. 1 Scope This Technical Specification gives the standard test method for determining residual stresses in polycrystalline materials by neutron diffraction. It is applicable to homogeneous and inhomogeneous materia
34、ls and to test pieces containing distinct phases. The principles of the neutron diffraction technique are outlined. Advice is provided on the diffracting lattice planes on which measurements should be made for different categories of materials. Guidance is provided about the directions in which the
35、measurements should be obtained and of the volume of material, which should be examined, in relation to material grain size and the stress state envisaged, when making measurements. Procedures are described for accurately positioning and aligning test pieces in a neutron beam and for precisely defin
36、ing the volume of material that is sampled when individual measurements are being made. The precautions needed for calibrating neutron diffraction instruments are described. Techniques for obtaining a stress free reference are presented. The methods of making individual elastic strain measurements b
37、y neutron diffraction are described in detail. Procedures for analysing the results and for determining their statistical relevance are presented. Advice is provided on how to determine reliable estimates of residual (or applied) stress from the strain data and of how to estimate the uncertainty in
38、the results. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 13925-3, N
39、on-destructive testing X-ray diffraction from polycrystalline and amorphous materials Part 3: Instruments1)1) To be published. DD CEN ISO/TS 21432:20052 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 absorption neutron capture by an atomic n
40、ucleus NOTE Tables of nuclear capture cross sections can be found under e.g. http:/ and links. 3.2 alignment adjustment of position and orientation of the specimen and all components of the instrument such that reliable strain measurements by neutron diffraction can be performed at the desired locat
41、ion in the specimen 3.3 anisotropy dependence of material properties on orientation 3.4 attenuation reduction of neutron intensity NOTE Attenuation can be calculated by using the so called “total neutron cross section”, which comprises absorption and different nuclear scattering processes. The atten
42、uation length is the distance within the material for which the primary neutron intensity is reduced by 1/e. 3.5 background intensity considered not belonging to the diffraction signal NOTE Background dependence on scattering angle or time-of-flight is not uncommon and can have an influence on the p
43、eak position resulting from data analysis. 3.6 beam defining optics arrangement of devices used to determine the properties of a neutron beam such as the wavelength and intensity distributions, divergence and shape NOTE These include devices such as apertures, slits, collimators, monochromators and
44、mirrors. 3.7 Bragg edge sudden change in neutron intensity as a function of wavelength or diffraction angle corresponding to =2dh k lwhere hkl indicates a diffracting lattice plane 3.8 Bragg peak intensity distribution of the diffracted beam for a specific hkl lattice plane 3.9 peak height maximum i
45、ntensity of the Bragg peak above the background 3.10 peak function analytical expression to describe the shape of the diffraction line DD CEN ISO/TS 21432:200533.11 peak position single value describing the position of a Bragg peak NOTE The peak position is the determining quantity to calculate stra
46、in. 3.12 diffraction scattering based on interference phenomena 3.13 diffraction elasticity constants elasticity constants associated with individual (hkl) lattice planes for a polycrystalline material NOTE They are often called elastic constants and can be denoted as Ehkl(diffraction elastic modulu
47、s) and hkl (diffraction Poissons ratio). 3.14 diffraction pattern distribution of scattered neutrons over the available range of wavelengths or times of flight and/or scattering angles 3.15 full width at half maximum FWHM width of the diffraction line at half the maximum height above the background
48、3.16 full pattern analysis determination of crystallographic structure and/or microstructure from a measured diffraction pattern of a polycrystalline material NOTE In general the full pattern analysis is termed after the method used (e.g. Rietveld refinement) See also single peak analysis. 3.17 gaug
49、e volume volume from which diffraction data are obtained NOTE This volume is determined by the intersection of the incident and diffracted neutron beams. 3.18 lattice parameters linear and angular dimensions of the crystallographic unit cell NOTE Most engineering materials have either cubic or hexagonal crystal structures. Hence the lattice parameters usually only refer to the lengths of the unit cell edges. 3.19 lattice spacing d-spacing spacing between adjacent crystallographic lattice planes 3.20 macrostress type I st
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