1、BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Cryogenic vessels - Toughness requirements for materials at cryogenic temperaturePart 2: Temperatures between -80 degrees C and -20 degrees CBS EN ISO 21028-2:2018National forewordThis British Standard is the UK impleme
2、ntation of EN ISO 21028-2:2018. It is identical to ISO 21028-2:2018. It supersedes BS EN 1252-2:2001, which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee PVE/18, Cryogenic vessels.A list of organizations represented on this committee can be obtained on req
3、uest to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2018 Published by BSI Standards Limited 2018ISBN 978 0 580 83704 3ICS 23.020.40Compliance with a British
4、 Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 April 2018.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS EN ISO 21028-2:2018EUROPEAN STANDARDNORME
5、 EUROPENNEEUROPISCHE NORMEN ISO 21028-2April 2018ICS 23.020.40 Supersedes EN 1252-2:2001EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGCEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2018 CEN Ref. No. EN ISO 21028-2:2018: EAll right
6、s of exploitation in any form and by any means reserved worldwide for CEN national MembersCryogenic vessels - Toughness requirements for materials at cryogenic temperature - Part 2: Temperatures between -80 degrees C and -20 degrees C (ISO 21028-2:2018)Rcipients cryogniques - Exigences de tnacit pou
7、r les matriaux temprature cryognique - Partie 2: Tempratures comprises entre -80 degrs C et -20 degrs C (ISO 21028-2:2018)Kryo-Behlter - Zhigkeitsanforderungen an Werkstoffe bei kryogenen Temperaturen - Teil 2: Temperaturen zwischen -80 C und -20 C (ISO 21028-2.2:2018)This European Standard was appr
8、oved by CEN on 12 January 2018.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
9、 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
10、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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hunga
11、ry, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.English VersionISO 21028-2:2018Foreword . iiiIntroduction iv1 Scope . 12 Normative references 13 Terms
12、and definitions . 14 Symbols 25 Requirements for steels with specified yield strength 460 N/mm235.1 General . 35.2 Temperature adjustments . 45.3 Procedure for base material 310 N/mm2, the impact energy at TKVgiven in Figure 1 and Figure 2 shall be 40 J.Where 27 J is specified in the product standar
13、d, Figure 3 for the post-weld heat-treated condition applies.For the as-welded case with SMYS in the range 310 N/mm2and 360 N/mm2, Figure 4 applies.For minimum yield strength 360 N/mm2, Figure 5 applies. ISO 2018 All rights reserved 3BS EN ISO 21028-2:2018ISO 21028-2:2018Table 1 Impact energy requir
14、ementsSpecified min. yield strength of base materialRequired impact energy KV (on 10 mm 10 mm test pieces)Figure defining required TKVN/mm2JNon-welded/ Post-weld heat-treated (PWHT)As-welded (A-W)310 27 1 2310 to 36040 1 227 3 436040 1 227 3 55.2 Temperature adjustmentsTSis a temperature adjustment
15、which may be used if the pressure-induced principal membrane stress does not exceed the percentage of the maximum allowable design stress or 50 N/mm2given in Table 2.Table 2 Temperature adjustmentsConditionPercentage of maximum allowable design stress Membrane stressb75 % to 100 % 50 % to 75 % 50 %
16、50 N/mm2Non-welded, final post-weld heat treateda0 C +10 C +25 C +50 CAs-welded and reference thickness 310 N/mm2and 360 N/mm2)NOTE Figure 4 is applicable to European materials covered by EN 13445-2/EN 13480-2. Verifications of suitability need to be made if applied to non-European materials; for th
17、is verification, see the principle of EN 13445-2/EN 13480-2.10 ISO 2018 All rights reservedBS EN ISO 21028-2:2018ISO 21028-2:2018KeyY TRdesign reference temperature, CX TKVimpact test temperature, CY eBreference thickness, mmRpproof stress, N/mm2Figure 5 Design reference and impact test temperature
18、As-welded condition (minimum yield strength 360 N/mm2)Table 6 Reference thicknessesConstruction detailAs-welded or post-weld heat-treatedReference thickness eB(where eB= e1, e2, e3or ef)Part A Weld Part BButt-welded components of unequal thickness A-W e1e2e2check e3in Figure 2 or Figure 4a ISO 2018
19、All rights reserved 11BS EN ISO 21028-2:2018ISO 21028-2:2018Construction detailAs-welded or post-weld heat-treatedReference thickness eB(where eB= e1, e2, e3or ef)Part A Weld Part BPWHT e1e2e3Branches and nozzles A-W e2e2e1PWHT e2e2e1A-W e2e2or e3if thickere1PWHT e2e2or e3if thickere1A-W e2e2or e3if
20、 thickere1PWHT e2e2or e3if thickere112 ISO 2018 All rights reservedBS EN ISO 21028-2:2018ISO 21028-2:2018Construction detailAs-welded or post-weld heat-treatedReference thickness eB(where eB= e1, e2, e3or ef)Part A Weld Part BA-W e3e2or e3if thickere2PWHT e3e2or e3if thickere2A-W e2e2e1or ef/4if thi
21、ckerPWHT e2e2e1bor ef/4 if thickerif necessary, check e1in Figure 1 or 3A-W e2e3e3or ef/4 if thickerPWHT e2e3e3cor ef/4 if thickerif necessary, check e1in Figure 1 or 3 ISO 2018 All rights reserved 13BS EN ISO 21028-2:2018ISO 21028-2:2018Construction detailAs-welded or post-weld heat-treatedReferenc
22、e thickness eB(where eB= e1, e2, e3or ef)Part A Weld Part BSlip-on and plate flanges A-W ef/4 e2e2PWHT ef/4 e2e2A-W ef/4 e2e2PWHT ef/4 e2e2Forged or cast welding neck flanges A-We2ccheck ef/4 in Figure 2 or 4e2e1PWHTe2or ef/4 if thickere2e114 ISO 2018 All rights reservedBS EN ISO 21028-2:2018ISO 210
23、28-2:2018Construction detailAs-welded or post-weld heat-treatedReference thickness eB(where eB= e1, e2, e3or ef)Part A Weld Part BPad-type flanges A-We2ccheck ef/4 in Figure 2 or 4e2e1PWHTe2or ef/4 if thickere2e1Flat ends A-W e1e1ef/4or e1if thickerPWHT e1e1ef/4or e1if thickerA-W e2e2e2ccheck ef/4 i
24、n Figure 2 or 4PWHT e2e2ef/4or e2if thicker ISO 2018 All rights reserved 15BS EN ISO 21028-2:2018ISO 21028-2:2018Construction detailAs-welded or post-weld heat-treatedReference thickness eB(where eB= e1, e2, e3or ef)Part A Weld Part BCovers and blind flanges A-W ef/4 PWHT ef/4 Tube plates A-W PWHT e
25、f/4 A-Wef/4or e2if thickere2e2PWHTef/4or e2if thickere2e216 ISO 2018 All rights reservedBS EN ISO 21028-2:2018ISO 21028-2:2018Construction detailAs-welded or post-weld heat-treatedReference thickness eB(where eB= e1, e2, e3or ef)Part A Weld Part BWelded into shell/channel A-Wef/4or e2if thickere2e2P
26、WHTef/4or e2if thickere2e2Preferably not to be usedForged tube plate with stubs A-We2ccheck ef/4 in Figure 2 or 4e2e2PWHTef/4or e2if thickere2e2 ISO 2018 All rights reserved 17BS EN ISO 21028-2:2018ISO 21028-2:2018Construction detailAs-welded or post-weld heat-treatedReference thickness eB(where eB=
27、 e1, e2, e3or ef)Part A Weld Part BA-We2aor e3if thickercheck ef/4 in Figure 2 or 4e2(e3)e2(e3)PWHTef/4or e2or e3if thickere2(e3)e2(e3)Tube-to-tube plate connection A-W e1e1PWHT e1e1aThe minimum test temperature of the conditions: e2(A-W), e3(PWHT) shall be taken.bThe minimum test temperature of the
28、 conditions: e1(A-W), ef/4 (PWHT) shall be taken.cThe minimum test temperature of the conditions: e2(A-W), ef/4 (PWHT) shall be taken.defmay be measured radially if advantageous.eSlope 1:4.fNot welded to shell or channel. Not applicable.18 ISO 2018 All rights reservedBS EN ISO 21028-2:2018ISO 21028-
29、2:2018Annex A (informative) Case proposal Technical justification for temperature adjustment termA.1 GeneralThe relevant regulations and standards of France, Sweden and Great Britain are based on fracture mechanics considerations: the basis of the French standard is the Sanz concept1, the Swedish st
30、andard is based on the work of Sandstrm2and the British standard is based on wide plate tests, the results of which were reassessed in 1998 on the basis of fracture mechanics considerations3. The fracture mechanics concepts take into account the influence of wall thickness, loading rate and that of
31、the conditions as-welded (A-W), unwelded and post-weld heat-treated (PWHT).In the German regulations and standards, minimum values for impact energy are determined on the basis of extensive operational experience; brittle fracture reducing-influences by means of reduction of the wall thickness, load
32、ing rates and stress-relief are not taken into consideration additionally.All concepts consider the influence of the load level on toughness (T2). Agreement was reached in the sub-group “low temperature” on the use of the brittle fracture concept of Sandstrm in the Swedish standard and contained in
33、Method 2, Technical requirements, previously entitled Code of practice developed from fracture mechanics. The agreement reached in favour of the Sandstrm concept was essentially due to two considerations: on one hand, the concept contains the formula by Sanz, which is used in the French standard, an
34、d on the other hand, the type of classification into strength classes is similar to existing standards, for example, British and Dutch.A.2 The brittle fracture conceptThe fundamental requirement of the brittle fracture concept is that components with defects do not fail with loading at the level of
35、the yield point, Rel. For this purpose, a certain material toughness is required for the material used, with:KIC KCComponentThe correlation of the fracture toughness with the impact energy forms the basis of the Sandstrm concept. The equation of Barsom and Rolfe, which is based on a large number of
36、steels, is used for the correlation. Later investigations have also confirmed the validity of the equations.KIC= E 1/2 (KV) 3/4In the correlation, two yield point ranges are assumed. The fracture toughness values in the transfer from brittle to ductile behaviour are correlated with the impact energy
37、 values. The results are as follows. Materials with Rel 310 N/mm2: requirements of 27 J(corresponds to KIC= 78 MPa m ); Materials with Rel310 N/mm2: requirements of 40 J(corresponds to KIC= 105 MPa m ). ISO 2018 All rights reserved 19BS EN ISO 21028-2:2018ISO 21028-2:2018A.3 Assumptions for the calc
38、ulation of the minimum operating temperatureA.3.1 Defect sizeFor the defect size, a semi-elliptical surface defect with a depth of 0,25 times the wall thickness was taken, which corresponds to the provisions of the ASME Code Section III.A.3.2 LoadsThe loads are assumed as 1,4 times the yield in the
39、A-W condition. The loads consist of the permitted primary stress and remaining residual stresses.In the PWHT state, loads are assumed to be equivalent to the yield point. On these assumptions, the minimum operating temperatures are calculated.A.3.3 Minimum metal temperatureThe calculation of the min
40、imum metal temperature is conducted according to Sandstrm with Formula (A.1) or Formula (A.2):TKKKKTTMcKV eln=+1010(A.1)orTKKKKTTMcKV eln=+60010(A.2)whereTKVis the impact test temperature, T27Jor T40J(KIC= 78 MPa m or 105 MPa m );Kcis the stress intensity factor, Kc= api()where is the stress coeffic
41、ient;a is the depth of the defect; is a coefficient; is constant 1/60;K0is constant 25 MPa m ;Teis the correction term for the influence of the component thickness.The correction term, Te, takes into consideration the influence of the wall thickness, e.NOTE For the purposes of this annex, e is the s
42、ymbol for wall thickness, while t is the symbol for component thickness.A.3.4 Temperature correction termThe starting factor of the concept is wall thickness 110 mm. If the wall thickness becomes less, this influences the stress condition and has beneficial effects on the brittle fracture safety. Th
43、e transition 20 ISO 2018 All rights reservedBS EN ISO 21028-2:2018ISO 21028-2:2018from the multi-dimensional strain condition to the level plain strain condition is taken into account by means of the correction term.In the Sandstrm concept, the influence of the yield point on the size of the plastic
44、 zone is also taken into consideration, in addition to the influence of the wall thickness. This leads to a correction term, tps.The correction term is proportional to (Kc/)2, where is the stress coefficient (Rel/Rm)/2 of the material.Definition of the temperature displacement, Te, by comparison of
45、tpswith the component thickness, t:e = t + 110 tpsprovided tps110Te= 0,53e 59 110 e 60Te= 0,97e 58, 60 e 30Te= 1,8e 110, 30 e 10TMis calculated as a function of the impact test temperature, TKVand the component thickness. The results of the calculations are Figures 1 to 5, which show the impact test
46、 temperatures as a function of wall thickness for the yield point ranges. Figure 1 shows the dependence for the condition unwelded and/or post-weld heat-treated. From a thickness of 60 mm, the impact test temperature is equal to the minimum metal temperature. If the component thickness becomes less,
47、 the strain condition is shifted in the direction of plain strain condition. This is taken into consideration with a lower minimum metal temperature.A.4 Temperature adjustment termIn the brittle fracture concept, loads at the level of the yield point and/or 1,4 times the yield point are assumed. If
48、the actual loads are under the maximum permissible loads, this is taken into account with a temperature adjustment term, TS. The temperature, TR, is determined from the minimum metal temperature and TS. The temperature adjustment term has the effect that the material can be used at lower temperature
49、s. The Swedish standard2, like AD-W 10 or BS 5500, provides for a temperature adjustment term for loads below the permissible load. ISO 2018 All rights reserved 21BS EN ISO 21028-2:2018ISO 21028-2:2018Annex B (informative) Example of calculation of the lowest temperature authorized during operationThis example illustrates the calculation of the lowest temperature authorized during operation for an as-welded stee
