International ISO Standard 4 IS0 4941 Third edition Steel and iron Determination of 2024-07 molybdenum content - Thiocyanate spectrophotometric method Aciers et fontes - Détermination des teneurs en molybdene - Méthode spectrophotométrique au thiocyanate Reference number IS0 4941:2024(en) @ ISO 2024 IS0 4941:2024(en) COPYRIGHT PROTECTED DOCUMENT @ IS02024 be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on or ISO's member body in the country of the requester. ISO copyright office CP 40i : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +41 22 749 01 11 Email: copyright@iso.org Website: www.iso.org Published in Switzerland @ IS0 2024 - All rights reserved i IS0 4941:2024(en) Contents Page Foreword. .iv 1 Scope .1 2 Normative references .1 3 ..1 Terms and definitions. 4 Principle .1 .2 5 Reagents .3 6 Apparatus. 7 Sampling and preparation of the test samples .3 8 ..3 Procedure 8.1 Test portion .4 8.2 Determination. .4 8.2.1 Preparation of the test solution ..4 8.2.2 Preparation of the compensating solution. .4 8.2.3 Formation and extraction of the coloured complex. 8.2.4 Spectrophotometric measurements. .5 8.3 Establishment of the calibration curve 8.3.1 Preparation of the calibration solutions, related to spectrophotometric measurements performed using cells with an optical path length of 10 mm ..5 .5 8.3.2 Spectrophotometric measurements 8.3.3 Piotting the calibration curve. .6 .6 9 Expression of results 9.1 Method of calculation ..6 9.2 Precision. ..7 Test report .7 10 Annex A (informative) Additional information on the international interlaboratory test ..8 ..10 Annex B (informative) Graphical representation of precision data Bibliography 11 @ IS0 2024 - All rights reserved iii