ISO INTERNATIONAL STANDARD 4945 Secondedition 2018-10 Steel Determination of nitrogen - Spectrophotometric method AcierDéterminationdeI'azote-Méthodespectrophotometrique Referencenumber IS04945:2018(E) TSo IS02018 IS04945:2018(E) COPYRIGHTPROTECTEDDOCUMENT IS02018 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 anyform or byany means,electronic or mechanical, including photocopying,or posting on the internet or an intranet, without prior written permission. Permission can be requested from either IO at the address beloworIso'smemberbodyinthecountryoftherequester. ISO copyright office CP 40i:Ch.de Blandonnet 8 CH-1214 Vernier, Geneva Phone:+41227490111 Fax: +4122 749 09 47 Email: [email protected] Website:www.iso.org Published in Switzerland ii @IS0 2018-All rights reserved IS04945:2018(E) Contents Page Foreword ..iv 1 Scope ..1 2 Normative references 3 Terms and definitions 4 Principle ..1 5 Reagents... ..2 6 Apparatus. .3 7 Sampling. .3 8 Procedure .3 8.1 Testportion ..3 8.2 Blank test. 4 8.3 Determination .4 8.3.1 Dissolution 4 8.3.2 Treatment of insoluble residue .4 8.3.3 Steamdistillation (seeFigureA.1,A.2orA.3) 4 8.3.4 Formation ofthecoloured complex 5 8.3.5 Spectrophotometricmeasurements 5 8.4 Establishmentofthecalibrationcurve.. 5 8.4.1 Preparationofthecalibrationsolutions .5 8.4.2 Spectrophotometricmeasurements 6 8.4.3 Plotting the calibration curve .6 9 Expressionofresults 9.1 Method of calculation. .6 9.2 Precision 7 10 Test report ..7 AnnexA(informative)Examplesofdistillationapparatus ..8 AnnexB (informative)Additional information on the international interlaboratorytest ..11 AnnexC(informative)Graphicalrepresentationofprecisiondata ..14 Bibliography ..15 IS02018-All rights reserved iii