ISO INTERNATIONAL STANDARD 7146-2 Second edition 2019-05 Plain bearings Appearance and characterization of damage to metallic hydrodynamic bearings Part 2: Cavitation erosion and its countermeasures Paliers lisses Aspect et caracterisation de I'endommagement des paliers metalliques a couche lubrifiante fluide Partie 2: Erosion de cavitation et sa contre-mesure Reference number IS0 7146-2:2019(E) ISO @ IS0 2019 IS0 7146-2:2019(E) COPYRIGHTPROTECTEDDOCUMENT @ ISO 2019 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior 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 CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +4122 749 0111 Fax: +41 22 749 09 47 Email: [email protected] Website: www.iso.org Published in Switzerland ii @ IS0 2019 - All rights reserved IS0 7146-2:2019(E) Contents Page Foreword ..iv Introduction. ..V 1 Scope. ..1 2 Normative references 3 Terms and definitions ..1 4 Cavitation erosion ..1 4.1 Mechanism of cavitation erosion .1 4.2 Classification of cavitation erosion ..4 4.3 General countermeasures against cavitation erosion .6 5 Five types of cavitation erosion .1 5.1 General 5.2 Flow cavitation erosion .7 5.2.1 Typical damage appearance. .7 5.2.2 Possible causes. .8 5.2.3 Possible countermeasures. .8 5.2.4 Typical examples (see Figures 4 to 8) ..8 5.3 Impact cavitation erosion. .10 5.3.1 Typical damage appearance. .10 5.3.2 Possible damage causes. .10 5.3.3 Possible countermeasures. ..10 5.3.4 Typical examples (see Figures 9 to 11) .11 5.4 Suction cavitation erosion 12 5.4.1 Typical damage appearance. .12 5.4.2 Possiblecauses 12 5.4.3 Possible countermeasures ..12 5.4.4 Typical examples (see Figures 12 to 14) .13 5.5 Discharge cavitation erosion . .14 5.5.1 Typical damage appearance. .14 5.5.2 Possible causes. .14 5.5.3 Possible countermeasures. .14 5.5.4 Typical examples (see Figures 15 to 16) .14 5.6 Miscellaneous cavitation erosion (see Figures 17 to 20) 15 5.6.1 Cavitation erosion caused by high-frequency vibration ("Vibration cavitation") 15 5.6.2 Cavitation erosion by elastic bearing deformation or abnormal combustion.. 15 5.6.3 Rippling or roughening (see Figures 19 and 20) 15 @ IS0 2019 - All rights reserved iii