DIN EN ISO 7539-6-2012 Corrosion of metals and alloys - Stress corrosion testing - Part 6 Preparation and use of precracked specimens for tests under constant load or constant disp.pdf

1、January 2012 Translation by DIN-Sprachendienst.English price group 18No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).IC

2、S 77.060!$y-c“1861064www.din.deDDIN EN ISO 7539-6Corrosion of metals and alloys Stress corrosion testing Part 6: Preparation and use of precracked specimens for tests underconstant load or constant displacement (ISO 7539-6:2011)English translation of DIN EN ISO 7539-6:2012-01Korrosion der Metalle un

3、d Legierungen Prfung der Spannungsrisskorrosion Teil 6: Vorbereitung und Anwendung von angerissenen Proben fr die Prfung unterkonstanter Kraft oder konstanter Verformung (ISO 7539-6:2011)Englische bersetzung von DIN EN ISO 7539-6:2012-01Corrosion des mtaux et alliages Essais de corrosion sous contra

4、inte Partie 6: Prparation et utilisation des prouvettes prfissures pour essais sous chargeconstante ou sous dplacement constant (ISO 7539-6:2011)Traduction anglaise de DIN EN ISO 7539-6:2012-01SupersedesDIN EN ISO 7539-6:2003-07www.beuth.deDocument comprises pagesIn case of doubt, the German-languag

5、e original shall be considered authoritative.4302.12 DIN EN ISO 7539-6:2012-01 2 A comma is used as the decimal marker. National foreword This standard has been prepared by Technical Committee ISO/TC 156 “Corrosion of metals and alloys” (Secretariat: SAC, China) in collaboration with Technical Commi

6、ttee CEN/TC 262 “Metallic and other inorganic coatings” (Secretariat: BSI, United Kingdom). The responsible German body involved in its preparation was the Normenausschuss Materialprfung (Materials Testing Standards Committee), Working Committee NA 062-01-71 AA Korrosion und Korrosions-schutz. By wa

7、y of derogation from the original ISO document, the equation below Figure 10 aHHaHHaHHVEK2332yLLI6,046,03 has been changed to read: aHHaHHaHHVEK2332LLI6,046,03 As it is not obvious from the figure whether or not VyLL refers to the Y-axis, the letter “y“ has been deleted from the index in the German

8、version, and correspondingly in the English version.The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 7539-1 DIN EN ISO 7539-1 ISO 11782-2 DIN EN ISO 11782-2 Amendments This standard differs from DIN EN ISO 7539-6:2003-07 as follows: a) t

9、he standard has been editorially revised and supplemented. Previous editions DIN EN ISO 7539-6: 1995-08, 2003-07 National Annex NA (informative) Bibliography DIN EN ISO 7539-1, Corrosion of metals and alloys Stress corrosion testing Part 1: General guidance on testing procedures DIN EN ISO 11782-2,

10、Corrosion of metals and alloys Corrosion fatigue testing Part 2: Crack propagation testing using precracked specimens EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 7539-6 October 2011 ICS 77.060 Supersedes EN ISO 7539-6:2003English Version Corrosion of metals and alloys - Stress corrosion

11、 testing - Part 6: Preparation and use of precracked specimens for tests under constant load or constant displacement (ISO 7539-6:2011) Corrosion des mtaux et alliages - Essais de corrosion sous contrainte - Partie 6: Prparation et utilisation des prouvettes prfissures pour essais sous charge consta

12、nte ou sous dplacement constant (ISO 7539-6:2011) Korrosion der Metalle und Legierungen - Prfung der Spannungsrisskorrosion - Teil 6: Vorbereitung und Anwendung von angerissenen Proben fr die Prfung unter konstanter Kraft oder konstanter Verformung (ISO 7539-6:2011) This European Standard was approv

13、ed by CEN on 14 October 2011. CEN members are bound to comply with the CEN/CENELEC Internal Regulations 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

14、standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language a

15、nd notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, L

16、ithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 20

17、11 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 7539-6:2011: EContents Page Foreword 3 1 Scope 4 2 Normative references 4 3 Terms and definitions .5 4 Principle 7 5 Specimens 8 5.1 General 8 5.2 Specimen design .9 5.3 Stress

18、 intensity factor considerations . 20 5.4 Specimen preparation 25 5.5 Specimen identification . 26 6 Initiation and propagation of fatigue cracks 26 7 Procedure 28 7.1 General . 28 7.2 Environmental considerations 28 7.3 Environmental chamber . 29 7.4 Environmental control and monitoring 30 7.5 Dete

19、rmination of KISCCby crack arrest 31 7.6 Determination of KISCCby crack initiation . 34 7.7 Measurement of crack velocity . 35 8 Test report . 36 Annex A (normative) Use of notched specimens for stress corrosion tests. 38 Annex B (normative) Determination of crack growth velocity 41 EN ISO 7539-6:20

20、11 (E) DIN EN ISO 7539-6:2012-01 2 Foreword This document (EN ISO 7539-6:2011) has been prepared by Technical Committee ISO/TC 156 “Corrosion of metals and alloys” in collaboration with Technical Committee CEN/TC 262 “Metallic and other inorganic coatings” the secretariat of which is held by BSI. Th

21、is European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2012, and conflicting national standards shall be withdrawn at the latest by April 2012. Attention is drawn to the possibility that some of the

22、elements of this 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. This document supersedes EN ISO 7539-6:2003. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the f

23、ollowing countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, S

24、lovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 7539-6:2011 has been approved by CEN as a EN ISO 7539-6:2011 without any modification. EN ISO 7539-6:2011 (E) DIN EN ISO 7539-6:2012-01 3 1 Scope 1.1 This part of ISO 7539 covers procedures for d

25、esigning, preparing and using precracked specimens for investigating susceptibility to stress corrosion. It gives recommendations for the design, preparation and use of precracked specimens for investigating susceptibility to stress corrosion. Recommendations concerning notched specimens are given i

26、n Annex A. The term “metal” as used in this part of ISO 7539 includes alloys. 1.2 Because of the need to confine plasticity at the crack tip, precracked specimens are not suitable for the evaluation of thin products, such as sheet or wire, and are generally used for thicker products including plate

27、bar and forgings. They can also be used for parts joined by welding. 1.3 Precracked specimens can be loaded with equipment for application of a constant load or can incorporate a device to produce a constant displacement at the loading points. Tests conducted under increasing displacement or increas

28、ing load are dealt with in ISO 7539-9. 1.4 A particular advantage of precracked specimens is that they allow data to be acquired from which critical defect sizes, above which stress corrosion cracking can occur, can be estimated for components of known geometry subjected to known stresses. They also

29、 enable rates of stress corrosion crack propagation to be determined. The latter data can be taken into account when monitoring parts containing defects during service. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated referen

30、ces, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 7539-1, Corrosion of metals and alloys Stress corrosion testing Part 1: General guidance on testing procedures ISO 11782-2:1998, Corrosion of metals and

31、alloys Corrosion fatigue testing Part 2: Crack propagation testing using precracked specimens EN ISO 7539-6:2011 (E) DIN EN ISO 7539-6:2012-01 4 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 7539-1 and the following apply. 3.1 crack length a effect

32、ive crack length measured from the crack tip to either the mouth of the notch or the loading point axis, depending on the specimen geometry 3.2 specimen width W effective width of the specimen measured from the back face to either the face containing the notch or the loading plane, depending on the

33、specimen geometry 3.3 specimen thickness B side-to-side dimension of the specimen being tested 3.4 reduced thickness at side grooves Bnminimum side-to-side dimension between the notches in side-grooved specimens 3.5 specimen half-height H 50 % of the specimen height measured parallel to the directio

34、n of load application for compact tension, double cantilever beam and modified wedge-opening-loaded test pieces 3.6 load P load which, when applied to the specimen, is considered positive if its direction is such as to cause the crack faces to move apart 3.7 deflection at loading point axis VLLcrack

35、 opening displacement produced at the loading line during the application of load to a constant displacement specimen 3.8 deflection away from the loading line V0crack opening displacement produced at a location remote from the loading plane, e.g. at knife edges located at the notch mouth, during th

36、e application of load to a constant displacement specimen 3.9 modulus of elasticity E elastic modulus (i.e. stress/strain) in tension EN ISO 7539-6:2011 (E) DIN EN ISO 7539-6:2012-01 5 3.10 stress intensity factor KIfunction of applied load, crack length and specimen geometry having dimensions of st

37、ress length which uniquely define the elastic-stress field intensification at the tip of a crack subjected to opening mode displacements (mode I) NOTE It has been found that stress intensity factors, calculated assuming that specimens respond purely elastically, correlate with the behaviour of real

38、cracked bodies, provided that the size of the zone of plasticity at the crack tip is small compared to the crack length and the length of the uncracked ligament. In this part of ISO 7539, mode I is assumed and the subscript I is implied everywhere. 3.11 initial stress intensity factor KIistress inte

39、nsity applied at the commencement of the stress corrosion test 3.12 plane strain fracture toughness KIccritical value of KIat which the first significant environmentally independent extension of the crack occurs under the influence of rising stress intensity under conditions of high resistance to pl

40、astic deformation 3.13 provisional value of KIcKQKQ= KIcwhen the validity criteria for plane strain predominance are satisfied 3.14 threshold stress intensity factor for susceptibility to stress corrosion cracking KISCCstress intensity factor above which stress corrosion cracking will initiate and g

41、row for the specified test conditions under conditions of high resistance to plastic deformation, i.e. under plane strain predominant conditions 3.15 provisional value of KISCCKQSCCKQSCC= KISCCwhen the validity criteria for plane strain predominance are satisfied 3.16 maximum stress intensity factor

42、 Kmaxin fatigue highest algebraic value of the stress intensity factor in a cycle, corresponding to the maximum load 3.17 0,2 % proof stress Rp0,2stress which must be applied to produce a plastic strain of 0,2 % during a tensile test 3.18 applied stress stress resulting from the application of load

43、to the specimen 3.19 stress intensity factor coefficient Y factor derived from the stress analysis for a particular specimen geometry which relates the stress intensity factor for a given crack length to the load and specimen dimensions EN ISO 7539-6:2011 (E) DIN EN ISO 7539-6:2012-01 6 3.20 load ra

44、tio in fatigue loading R algebraic ratio of minimum to maximum load in a cycle: min minmax maxPKRPK 3.21 crack velocity instantaneous rate of stress corrosion crack propagation measured by a continuous crack monitoring technique 3.22 average crack velocity average rate of crack propagation calculate

45、d by dividing the change in crack length due to stress corrosion by the test duration 3.23 specimen orientation fracture plane of the specimen identified in terms of firstly the direction of stressing and secondly the direction of crack growth expressed with respect to three reference axes identifie

46、d by the letters X, Y and Z NOTE Z is coincident with the main working force used during manufacture of the material (short-transverse axis); X is coincident with the direction of grain flow (longitudinal axis); Y is normal to the X and Z axes. 4 Principle 4.1 The use of precracked specimens acknowl

47、edges the difficulty of ensuring that crack-like defects introduced during either manufacture or subsequent service are totally absent from structures. Furthermore, the presence of such defects can cause a susceptibility to stress corrosion cracking which in some materials (e.g. titanium) may not be

48、 evident from tests under constant load on smooth specimens. The principles of linear elastic fracture mechanics can be used to quantify the stress situation existing at the crack tip in a precracked specimen or structure in terms of the plane strain-stress intensity. 4.2 The test involves subjecting a specimen in which a crack has been developed by fatigue from a machined notch to either a constant load or displacement at the loading points during exposure to a chemically aggressive environm