ISO INTERNATIONAL STANDARD 4942 Second edition 2016-07-01 Steels and irons Determination of vanadium content N-BPHA spectrophotometric method Aciers et fontes Détermination de la teneur en vanadium - Méthode spectrophotométrique au N-BPHA Reference number ISO 4942:2016(E) ISO International Organization for Standardization see=ZHEJIANG INST OF STANDARDIZATION C1 5956617 @IS02016 vided by IHS under I Not for Resale, 2016/8/16 08:31:39 No reproduction or networking permitted without license from IHS IS0 4942:2016(E) COPYRIGHT PROTECTED DOCUMENT IS0 2016, 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. ISO copyright office Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 [email protected] www.iso.org Internatinir DrganizationforStandardization Licensee-ZHEJIANG INST OF STANDARDIZzRoISQ6- All rights reserved Not for Resale, 2016/8/16 08:31:39 No reproduction or networking permited without license from IHS IS0 4942:2016(E) Contents Page Foreword ..iv 1 Scope .1 2 Normative references 3 Terms and definitions 4 Principle 5 Reagents. 6 Apparatus. ..3 7 Sampling. ..3 8 Procedure .3 8.1 Test portion 8.2 Blank test. .3 8.3 Determination .4 8.3.1 Preparation of the test solution .4 8.3.2 Oxidation of vanadium .4 8.3.3 Colour development and extraction ..4 8.3.4 Spectrophotometric measurements 4 8.4 Establishment of the calibration curve. ..5 8.4.1 Preparation of the calibration solutions. 5 8.4.2 Spectrophotometric measurements ..5 8.4.3 Piotting of the calibration curve .5 9 Expression of results .5 9.1 Method of calculation ..5 9.2 Precision. ..6 10 Special cases. ..7 11 Test report. .7 Annex A (informative) Additional information on the international interlaboratory test .8 Annex B (informative) Graphical representation of precision data .9 Bibliography .10 ii nSee=ZHEJIANG INST OF STANDARDIZATION C1 5956617 vided by IHS under lic se with ISt dwithout license from IHS