ISO/TS TECHNICAL SPECIFICATION 20273 First edition 2017-08 Guidelines on weld quality in relationship to fatigue strength Lignes directrices sur la qualité de la soudure en rapport a la resistancealafatigue Reference number IS0/TS20273:2017(E) Tso iiw @IS02017 IS0/TS 20273:2017(E) COPYRIGHTPROTECTEDDOCUMENT IS0 2017,Published in Switzerland 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. IsOcopyrightoffice Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii @ IS0 2017 - All rights reserved IS0/TS20273:2017(E) Contents Page Foreword ..iv Introduction. ..V 1 Scope 2 Normative references 3 Terms and definitions 4 Symbols and abbreviated terms ..2 5 Background. .3 5.1 General .3 5.2 Design for purpose. .3 5.3 Fatigue assessment procedures .5 5.4 Classification of weld imperfections and features ..6 Weld quality levels for fatigue loaded structures .7 6 6.1 Assessment of weld quality. .7 6.2 Requirements for a production standard weld quality 6.2.1 General. .8 6.2.2 Effect of toe geometry ..8 6.2.3 Effect of misalignment ..10 6.2.4 Effect of undercut. .12 6.2.5 Effect of cold laps.. ..13 6.2.6 Effect of inclusions and porosity .14 6.2.7 Effect of cracks and crack-like imperfections. .15 6.3 Design of Experiments (DoE) using simulation .. .19 6.3.1 General. .19 6.3.2 Parameters using the effective notch method on butt welds .20 6.3.3 Parameters using the effective notch method on fillet welds 21 6.4 Fatigue design of high quality welds. .23 6.4.1 General .23 6.4.2 Effect of improvement methods. .23 6.4.3 Improvement of shape of weld toe .24 6.4.4 Improvement by compressive residual stress. .24 7 Root side requirements. .24 7.1 General 24 7.2 Joints with weld root as weakest point. 24 7.3 Designation for penetration 25 7.4 Design of Experiments in load carrying joints 26 7.5 Throat size vs penetration. .28 8 Fitness for service .30 8.1 General 30 8.2 Fatigue assessment by crack propagation. 32 8.3 Material parameters for crack propagation 32 8.4 Formulae for stress intensity factors. .33 8.4.1 General. .33 8.4.2 Standard solutions .33 8.4.3 Solutions for magnification function, Mk .35 8.4.4 Examples of a fracture mechanics assessment .37 Bibliography .43 @ IS0 2017 - All rights reserved iii