1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN ISO 7539-8:2008 ICS
2、 77.060 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Corrosion of metals and alloys Stress corrosion testing Part 8: Preparation and use of specimens to evaluate weldmentsNational foreword This British Standard is the UK implementation of EN ISO 7539-8:2008. It is identical
3、 with ISO 7539-8:2000. It supersedes BS ISO 7539-8:2000 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee ISE/NFE/8, Corrosion of metals and alloys. A list of organizations represented on this committee can be obtained on request to its secretary. This
4、publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. BS EN ISO 7539-8:2008 This British Standard, having been prepared under the directi
5、on of the Engineering Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 September 2000 BSI 2009 Amendments/corrigenda issued since publication Date Comments 31 October 2009 This corrigendum renumbers BS ISO 7539-8:2000 as BS EN ISO 7539-8:2008
6、 ISBN 978 0 580 60529 1EUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM ENISO75398 April2008 ICS77.060 EnglishVersion CorrosionofmetalsandalloysStresscorrosiontestingPart 8:Preparationanduseofspecimenstoevaluateweldments (ISO75398:2000) CorrosiondesmtauxetalliagesEssaisdecorrosion souscontraintePartie
7、8:Prparationetutilisationdes prouvettespourvaluerlesassemblagessouds(ISO 75398:2000) KorrosionderMetalleundLegierungenPrfungder SpannungsrisskorrosionTeil8:Vorbereitungund AnwendungvonProbenzurBewertungvon Schweiverbindungen(ISO75398:2000) ThisEuropeanStandardwasapprovedbyCENon21March2008. CENmember
8、sareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEuropean Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcerningsuchnational standardsmaybeobtainedonapplicationtotheCENManagementCentreortoanyCENmember.
9、 ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytranslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheCENManagementCentrehasthesamestatusasthe officialversions. CENmembersarethenationalstandardsbodiesofAustria,Belgiu
10、m,Bulgaria,Cyprus,CzechRepublic,Denmark,Estonia,Finland, France,Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Romania,Slovakia,Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN
11、DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2008CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.ENISO75398:2008:EEN ISO 7539-8:2008 (E) Foreword The text of ISO 7539-8:2000 has been prepared by Techni
12、cal Committee ISO/TC 156 “Corrosion of metals and alloys” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 7539-8:2008 by Technical Committee CEN/TC 262 “Metallic and other inorganic coatings” the secretariat of which is held by BSI. This European Standar
13、d shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2008, and conflicting national standards shall be withdrawn at the latest by October 2008. Attention is drawn to the possibility that some of the elements of thi
14、s document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Stan
15、dard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.
16、 Endorsement notice The text of ISO 7539-8:2000 has been approved by CEN as a EN ISO 7539-8:2008 without any modification. BS EN ISO 7539-8:2008ISO 75398:2000(E) ISO 2009 All rights reserved iii Contents Page 1 Scope 1 2 Normative references 1 3 Terms and definitions .2 4 Special considerations for
17、weldments 3 5 Specimen types4 6 Preparation of weldments and test specimens 8 7 Testing Procedures .10 8 Assessment11 9 Test report 11 Annex A (informative) Terms and definitions which have not been internationally agreed .13 Bibliography18 BS EN ISO 7539-8:2008This page deliberately set blankINTERN
18、ATIONAL STANDARD ISO 75398:2000(E) ISO 2009 All rights reserved 1 Corrosion of metals and alloys Stress corrosion testing Part 8: Preparation and use of specimens to evaluate weldments 1 Scope This part of ISO 7539 covers the procedures available for stress corrosion testing of welded specimens and
19、examines the additional factors which must be taken into account when conducting tests on welded specimens. In particular this part of ISO 7539 gives recommendations for the choice of specimens and test procedures to determine the resistance of a metal to stress corrosion when it is welded. The term
20、 “metal”, as used in this part of ISO 7539, includes alloys. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 7539. For dated references, subsequent amendments to, or revisions of, any of thes
21、e publications do not apply. However, parties to agreements based on this part of ISO 7539 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to a
22、pplies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 8571:1998, Welding and allied processes Vocabulary Part 1: Metal welding processes. ISO 75392:1989, Corrosion of metals and alloys Stress corrosion testing Part 2: Preparation and use of bentbeam specim
23、ens. ISO 75393:1989, Corrosion of metals and alloys Stress corrosion testing Part 3: Preparation and use of Ubend specimens. ISO 75394:1989, Corrosion of metals and alloys Stress corrosion testing Part 4: Preparation and use of uniaxially loaded tension specimens. ISO 75395:1989, Corrosion of metals
24、 and alloys Stress corrosion testing Part 5: Preparation and use of Cring specimens. ISO 75396: 1) , Corrosion of metals and alloys Stress corrosion testing Part 6: Preparation and use of pre cracked specimens. ISO 75397:1989, Corrosion of metals and alloys Stress corrosion testing Part 7: Slow stra
25、in rate testing. IEC 60050851 (199108), International Electrotechnical Vocabulary Chapter 851: Electric Welding. 1) To be published. (Revision of ISO 75396:1989) BS EN ISO 7539-8:2008ISO 75398:2000(E) 2 ISO 2009 All rights reserved 3 Terms and definitions For the purposes of this part of ISO 7539 th
26、e following terms and definitions apply. 3.1 welding operation which unites materials by means of heat or pressure, or both, in such a way that there is continuity in the nature of the materials which have been joined and in which filler metal, the melting temperature of which is of the same order a
27、s that of the parent metal(s), may or may not be used NOTE This definition also includes surfacing. ISO 8571 3.1.1 fusion welding welding involving localized melting without the application of force and with or without the addition of filler metal ISO 8571 3.1.2 arc welding fusion welding in which h
28、eat for welding is obtained from an electric arc or arcs ISO 8571; IEC 60050851 3.1.3 diffusion welding pressure welding in which the workpieces are kept in contact under a specified continual pressure and are heated, either on their faying surfaces or in their entirety, at a defined temperature for
29、 a controlled time NOTE 1 This process results in local plastic deformation and also, owing to the very close contact between the surfaces, the diffusion of the atoms through the interface. The end result is thus complete continuity of the material. NOTE 2 The operation may take place in a vacuum, u
30、nder a gas shield or in a fluid, preferably without the addition of a filler metal. S e eFi gu re1 . ISO 8571 BS EN ISO 7539-8:2008ISO 75398:2000(E) ISO 2009 All rights reserved 3 Key 1 Induction heating element 2 Work chamber 3W o r k p i e c e 4W e l d Figure 1 Diffusion welding 3.2 arc voltage vo
31、ltage across the arc, including the anode and cathode voltage drop, measured as near as possible to the arc IEC 60050851 See annex A. 4 Special considerations for weldments 4.1 General The factors given in this clause may all influence the corrosion and/or mechanical properties of a weldment relativ
32、e to that of the parent metal and their effects may require consideration in stress corrosion test procedures. Whilst the considerations listed below are relevant to the more common fusion welding processes, similar consideration shall also be given to solid phase (nonfusion) welding processes and d
33、iffusion welding. Weld regions are more likely than the parent metal to contain defects which may influence corrosion and stress corrosion behaviour, e.g. microcracking, lack of fusion and porosity. For this reason, examination of the weld shall be undertaken to assess whether the failure of any spe
34、cimen is the result of preexisting defects rather than stress corrosion. It is recommended that the weldment be characterized with regard to residual welding stresses, surface condition and weld defects prior to testing. See clause 7. 4.2 Changes in microstructure In fusion welding, the application
35、of heat to a parent metal produces microstructural changes in the heat affected zone (HAZ) of the parent metal adjacent to the weld junction. A rapidlycooled weld metal differs microstructurally BS EN ISO 7539-8:2008ISO 75398:2000(E) 4 ISO 2009 All rights reserved and chemically from the parent meta
36、l and is more typical of a cast structure. These differences may influence both weldment corrosion and mechanical properties, as well as susceptibility to stress corrosion cracking. Some alloys such as CMn steels display a visible HAZ. However, in some alloys, welding may also produce precipitation
37、and segregation effects within the parent metal remote from the visible HAZ. 4.3 Nonmetallic inclusions In addition to changes in chemical composition, the welding procedure and conditions used may result in a weld metal with a nonmetallic inclusion content and distribution different from that of th
38、e parent metal. This may influence weldment corrosion and stress corrosion cracking behaviour. 4.4 Stress concentration effects Shrinkage stresses following welding will introduce residual welding stresses which will be both transverse and longitudinal with respect to the welding direction (and thro
39、ugh thickness in thickwalled samples). Tensile stresses are usually generated at the weld, with balancing compressive stresses in the parent metal. In addition, weld geometry may cause further stress concentration effects. 5 Specimen types 5.1 General The design and type of specimen used depend on t
40、he form of the metal from which the specimen is to be made and on the objective of the test. The test specimens described in ISO 7539 parts 27 are suitable for tests on weldments, subject to the additional considerations presented in this part of ISO 7539. In addition, a number of other types of spe
41、cimens, as described in 5.2.1 to 5.2.8 below, can be used. Specimens can be prepared from weldments in the aswelded or postweld heattreated conditions. It is recommended that specimens be tested in the same condition of heat treatment as that of the intended application. 5.2 Types of specimen 5.2.1
42、Flat weldment S e eFi gu re2 . This type of weldment is applicable for all tension and bend specimens and for any welding procedure whether involving single or multipass welds. The weldment may also be used to evaluate the effect of residual welding stresses. 5.2.2 Circular bead weldment S e eFi gu
43、re3 . The welding procedure involves one circular bead deposit of weld metal. The circular weld develops residual welding stresses. It is applicable to any material form that can be machined to the recommended size as specified in Figure 3. BS EN ISO 7539-8:2008ISO 75398:2000(E) ISO 2009 All rights
44、reserved 5 5.2.3 Beadonbar weldment S e eFi gu re4 . The longitudinal fusion welds at diametrically opposite positions on the bar develop residual welding stresses in the bar. Hence, this weldment can be used to evaluate the tendency for stress corrosion cracking of the parent metal. It is applicabl
45、e to materials that can be machined to approximately 25 mm diameter. 5.2.4 Direct tension specimen S e eFi gu re5 . This specimen type is stressed in uniaxially loaded tension (see ISO 75394 and ISO 75397). Notches, with or without precracks, may be introduced into the weld metal, parent metal or he
46、at affected zone (see ISO 75396). These specimens also may be made exclusively from weld metal. 5.2.5 Ubend specimen S e eFi g u re6 . The Ubend specimen is applicable to any weldment that can be formed into a Ushape without mechanical cracking or localized bending in the heat affected zone (see ISO
47、 75393). The bending operation after welding creates high levels of elastic and plastic strain resulting in a wide range of stresses in a single specimen. The presence of residual welding stresses makes this a particularly severe test procedure. 5.2.6 Bentbeam specimens S e eFi gu re7 . These specim
48、ens are machined from welded plate into rectangular bar with the welding direction normal to or parallel to the axis of the specimen (see ISO 75392). They can be loaded in 3point or 4point bending to measure the stress corrosion tendencies in the weld region. 5.2.7 Precracked specimens S e eFi gu re8 . Precracked specimens can be used to measure the tendency for stress corrosion cracking (see ISO 75396) in various parts of the weldment. Caution should be exercised in the interpret
