ISO INTERNATIONAL STANDARD 21601 First edition 2013-04-01 Corrosion of metals and alloys Guidelines for assessing the significance of stress corrosion cracks detected in service Corrosion des meétaux et alliagesLignes directrices pour évaluer I'importance des fissures de corrosion sous contrainte détectées en service Reference number ISO 21601:2013(E) LSO IS02013 IS0 21601:2013(E) COPYRIGHTPROTECTED DOCUMENT @ISO2013 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 : CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland ii @ IS0 2013 - All rights reserved IS0 21601:2013(E) Contents Page Foreword ..iv 1 Scope .1 2 Normative references ..1 3 Principle ..1. 4 Characterization of the nature and origin of the crack 5 Definition of service conditions and system history ..2 5.1 Stresses. .2 5.2 Service environment .3 6 Material characteristics. ..4 6.1 Cold work. .4 6.2 Welding. ..4 6.3 Ageing. .5 6.4 Microstructural orientation .5 7 Prediction of Kiscc and crack growth rates 7.1 Kiscc. 6 7.2 Prediction of growth rates below Kiscc 7.3 Crack growth above Kiscc ..10 7.4 Non-propagating cracks .15 7.5 Probabilistic issues. ..15 8 Structural integrity assessment ..15 9 Modification of service conditions to mitigate crack growth .17 9.1 Temperature change. .17 9.2 Reduction of operational stresses .18 9.3 Alteration/more rigorous control of the environment .18 Bibliography .19 @ IS0 2013 - All rights reserved iii