1、A BRITISH STANDARD Corrosion of metals and alloys - Stress corrosion testing Part 3. Preparation and use of U-bend specimens The European Standard EN IS0 7539-3 : 1995 has the status of a British Standard BS EN IS0 7539-3 : 1995 BS 6980 : Part 3 : 1990 the Non-fernaus Metals Standards Policy Committ
2、ee, Amd.No. was published under the authority of the -) and Non-ferrous Metals Standards Policy Committee (NFM/-) to Technical Committee ISM/NFM/8, upon which the following bodies were represented: Aluminium Federation British Gas plc British Steel Industry Department of Trade and Industry (National
3、 Physical Laboratory) Department of Transport (Transport and Road Research Laboratory) Electricity Supply Industry in England and Wales Institution of Corrosion Science and Technology Institution of Structurai Engineers Society of Chemical Industry United Kingdom Atomic Energy Authority Welding Inst
4、itute CEN ENxISOs7539- 3 95 3404589 OLO7L07 bT4 = BS 6980 : Part 3 : 1990 _. ._._- _ -_ Contents Committees responsible National forcwoid Method 1 Scope 2 Normative reference 3 Definitions 4 Principle 5 Specimens 6 Procedure 7 Assessment of results 8 Test reDort Page Inside front covc I II Figures 1
5、 Typical stressed -bends a? , 2 Methods of stressing U-bend specimens 2 National foreword Cross-references International standard Corresponding British Standard IS0 7.539-1 : 1987 BS EN IS0 TES39 CO-YXY.OI/ of tt/1l*S (ittl illOl/.S - Stress cormsioti tesliry Part 1 : 199-5 Giritlc /o /eq/ity ptatrd
6、utrs (Identical) CEN EN*IS0*7539- 3 95 I 3404589 Ol107109 477 = EUROPEAN STANDMD NORME E17ROPfiE“E EUROPAISCHE NORM English version Corrosion of metals and alloys - Stress corrosion testing - Part 3: Preparation and use of U-bend specimens (IC0 7539-3 : 1989) Corrosion des mtaux et alliages - Essais
7、 de corrosion sous con-ainte - Partie 3: Prparation et utilisation des prouvettes cintres en U Bugelproben Korrosion de Metalle iuid kgiemgen - Priiung der Spannungsti3kotocion - Teil 3: Vorbereitung unci Anwendung von (IS0 7539-3 1989) (Is0 7539-3 : 19S9) This European Standard was approved by CEN
8、on 1995WOS. CEN ineiiibeis are bound to coinply with the CEN/CENELEC Internal Regulations vlticti stipulate the conditions for giving this European Standard the status of a iiatioiial standard without any alteration. Up-to-date lists and bibliographical rderences concerning such niit ional standards
9、 niay be obtained on application to the Central Secretatuiat or to my (EN iiieiiibcxr. This European Standard exists in three official versions (Etiglisti, French, Gernian). A version in any other language niade by translation tinder t.he responsibility of a CEN member into its own language and noti
10、fied to the Cent.ra1 Secretariat has the same status as the officiai versions. CEN members are the national standards bodies of Austria, Belgiim, Denniark, Finiand, kance, Germany, Greece, keland, Ireland. Italy. Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and 1 -nit ed Kin
11、gdoni. CEN European Comniittee for Standardization Coniiti. Europki de Nomidisation Europ,iis iimuls rw?rved in all countries to CEN and its nien-ibets. Ref. NO. EN IS0 7539-3 1995 E Page 2 EN IS0 7539-3 : 1995 Foreword Ttus Eiiropc;ui Sttuidard tias tttri taken over by the Technical Coniiiuttee CEN
12、iTC: 262, Protection of iiietdic niaterials against corrosion, from the work of ISOflC 156, Corrosion of nietalc and alloys, of the international Organization for Standardization (ISO). This European Standard sha be given the status of a national standard, either by publication of an identical text
13、or by endorsement, at the latest by November 1995, and conflicting nationai standards slid be Withdrawn at the latest by November 1995. According to Lhe CENICENELEC Internal Regulations, the following couritries are bound to implement this European Standard: Austria, Belgium, enniark, Finiand, Franc
14、e, Germany, Greece, Iceland, Ireland, Italy, Luxenibourg, Netherlands, Norway, Portugai, Spain, Sweden, Switzerland and Uniteci Kingom. INTERNATONAL STANDARD IS0 7539-3 : 1983 (E) Corrosion of metals and alloys - Stress corrosion testing - Part 3: Preparation and use of U-bend specimens WARNING - U-
15、bend specimens made from high strength materials may fracture rapidly; pieces may fly off at high velocity and can be dangerous. Personnel installing and examining specimens must be made aware of this possiblity and be protected against injury. 1 Scope 1.1 This part of IS0 7539 covers procedures for
16、 designing, preparing and using U-bend test specimens for investigating the susceptibility of a metal to stress conosion. The term “metal” as used in this part of IS07539 includes alloys. 1.2 U-bend specimens may be used to test a variety of product forms. They are used principally for sheet, plate
17、or flat extruded material, which conveniently provides flat specimens of rectangular cross-section, but may also beemployed for wire or rod, or for machined specimens of circular cross-section. They can also be used for parts joined by welding. 1.3 The U-bend test is frequently used to establish whe
18、ther a metal is susceptible to stress corrosion cracking in a given environment. It is used in laboratories to screen materials for susceptibili for specific applications and in Senrice environ- ments to assess the risk of failure. 1.4 The principal advantages of the test are -tS SinpliCity and its
19、consequent adaptability for use in plant. A disadvantage is that stresses cannot be quantified with accuracy and if this is desired an alternative method of stressing should be used. 2 Normative reference The following standard contains provisions which. through reference in this text, constitute pr
20、ovisions of this part of IS0 7539. At the time of publication, the dion indicated was valid. All standards are subject to revmOn, and parties to agreements based on this part of IS0 7539 are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below
21、. Members of IEC and IS0 maintain registers of currently valid Intemational Standards. IS0 7539-1 : 1987, Corrosion of metal and alloys - Stress corrosion testing - Part I: General guidance on testing procedures. 3 Definitions For the purposes of this part of IC0 7539, the definitions given in IS0 7
22、5391 are applicable. 4 Principle 4.1 The test consists in exposing to the corroding medium a piece of metal bent into a U-shape and held in a manner which ensures that there are initial tensile stresses ranging up to the yield point over a proportion of the surface. In the act of forming specimens,
23、varying amounts of cold work may be introduced and this deformation may influence the stress corrosion cracking tendency as compared to that of the material in the original condition. 4.2 The test may be performed under laboratory conditions by exposing the specimens to simulated service conditions
24、or it may be carried out in the actual service environment at the location of interest. 4.3 The objective of the test is either to establish whether a metal is suitable for a proposed application or to assess the risk of stress corrosion cracking of metals used in existing plant under service condit
25、ions. 4.4 Wide variations in test results may be obtained for a given metal and environment even when testing nominally identical specimens and the replication of tests is frequently necessary. If specimens are prepared to different sizes or orikntations or are subjected to different stressing proce
26、dures, test results may be even more variable. 1 IS0 7539-3 : 1989 (1 5 Specimens 5.1 A variety of specimen shapes and sizes can be employed and figure 1 shows examples of specimens often used. Figure 2 indicates come methods of forming the specimens. To simulate crevice conditions, it is possible t
27、o form a second specimen over the first, thereby creating a crevice beween the two, and to test the composite specimen see figure ldll. 5.2 When stressing specimens by fastening after forming, care should be taken to ensure that the deflection is restored to that obtained at the end of the forming o
28、peration. 5.3 Specimens for use in seMce conditions should be securely fixed to avoid movement through the system and should be accessible for inspection or remaval. Their design and method of fixing should be considered as a whole. a) 5.4 If more than one metal is present in a system, specimens sho
29、uld be electrically insulated to avoid galvanic effects. 5.5 Specimens should be fabricated from representative material with due regard to such factors as rolling direction and heat treatment. If relevant, welded specimens should be tested, and the con- figuration in service should be borne in mind
30、 when preparing the specimens. 5.6 For laboratory testing a fine surface finish is frequently used since it allows early detection of cracks, but for in-service testing a surface finish representative of the plant should be employed. For further comments relating to surface condition, IS0 7539-1 sho
31、uld be consulted. bl Figure 1 - Typical stress bl orientation, type and size of test specimens and their surface preparation; c test environment, including location of specimens for in-service tests; dl the times at which observations were made and when cracks became visible. Publications referred t
32、o See national foreword. BS 6980 Part 3 : 1990 IS0 7539-3 : 1989 BSI 2 Park Street London W 1A 2US BSI Linford Wood Milton Keynes MK14 6LE CEN EN*IS0*7539- 3 95 m 3404589 OL07LL4 834 m BSI - British Standards Institution I3SI is t.hc independcrit nat.iona1 tty rcsponsit)lc for preparing British Stan
33、tlards. it presents the I!K vim7 on standards in Eurqw and at the int.crnatiotia1 Icvcl. It is i ncc trp) rat,ed by Kc )ya i Cliai-ter. Contract requirements A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for thei
34、r correct application. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions. Any person who finds an inaccuracy or ambiguity while using this Brit,ish Standard should notify 231 without delay
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38、908 220022. Copyright Copyright subsists in ail BSI publications. No part of this publication may be reproduced in any form without the prior permission in writing of BSI. This does not preclude the free use, in the course of implementing the standard, of details such as symbols and size, type or gr
39、ade designations. Enquiries about copyright should be made to the Copyright Manager, Marketing at Milton Keynes. CEN EN*ISO*7539- 3 95 3404589 0107115 770 W AMD 8712 Amendment No. 1 published and effective from 15 October 1994 to BS 6980 : Part 3 : 1990 Stress corrosion testing Part 3. Method for th
40、e preparation and use of U-bend specimens NOTE. The European Committee for standardizatioii (CEN) has accepted IS0 75139-3 : is9 as a European Standard designated as EN IS0 7539-3 : 1995. This aiiiendiiieiit iiiiplenimis EN IC0 E5394 : 1395 as a British Slaiidard iii the 13s EN series. Implementatio
41、n of European Standard Front cover Delete the outside front cover and substitute the attached. AMD 871UOctober 1995 - National foreword Delete aii of the existing text of the national foreword arid substitute the “olloi+ing. This Part of BS EN IS0 7539 has been prepared under the direction of the En
42、gineering Sector Board. It is identical with IS0 539-3 : 1989 Comxioti of iric.s a.nd alloys - Stress corrosion testing - Part 3: Pt-epa,mtio.n and zise of il-boid specimens, published by the International Organization for Standardizaton (ISO). BS EN IS0 7539 comprises the foliowing parts: Part I Ga
43、.leral guiance on. testing pincedures Part 2 Prepamtion and use of bent-beam specimens Part 3 Prepamtion and use of U-bold specimu Part 4 P-paration and use of uniaria. ioucx tension specimens Part 5 Preparation and use of C-ring specimens Part 6 Preparation and use of re-ciwed spx+.rneru Part 7 Sim
44、u strain mie te.sling Cross-references International standard IS0 7539-1 : 1987 CEN EN*ISO*7539- 3 75 I 3404589 0107Llb 607 EN title page and foreword Iriiiiieidately after the national foreword insert the attached EN title page aiid foreword page. AM 8713/0ctober 1995 _-_ - -_-_ 2 CEN EM*ISO*7539-
45、3 95 3404587 OLO7LL7 543 - BRITISH STANDARD . I . . ,. “,. ., Corrosion of metals and alloys - Stress corrosion testing Part 3. Preparation and use of U-bend specimens The European Standard EN IS0 7539-3 : 1995 has the status of a British Standard BS EN IS0 7539-3 : 1995 CEN EN*IS0*7539- 3 95 = 3404
46、589 OL07Ll18 Y8T EUROPEAN STANDARD NORNIE EUROPENNE EUROPGCHE NORM EN IS0 7539-3 May 1995 English version Corrosion of metals and alloys - Stress corrosion testing - Part3: Preparation and use of U-bend specimens (IS0 7539-3 : 1989) Corrosion des mtaux et alliages - Essais de corrosion sous contrain
47、te - Partie 3 Prparation et utilisation des prouvettes cintres en U Bgelpioben Korrosion de Metaile Luid Legierungen - pnifung der Spannurigsrikoi-rosion - Teil 3 Vorbereitung und Anwendung von (Is0 7539-3 : 1989) (IS0 7539-3 : 1989) This European Standard was approved by CEN on 199:504-08. CE3 nien
48、ibers are bound to comply with the CENKENELEC Internai Kegu1at.ion.s which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national st,ind,u-ds may be obtained on appl
49、ication to the Centrai Secretariat 01 to any VEN nieniber. This European Standard exists in three official versions (English, French, German). A version in any other language niade by translation under the responsibility of a CEN member into its own language and notified to the Cent.rai Secretariat has the same stat= as the official versions. CEN members are the naionai standards bodies of Austria, Belgium, Denniark, Fniand, France, Germany, Greece, Iceland, Ireland, Italy.
