ISO INTERNATIONAL STANDARD 10702 First edition 1993-07-01 Steel and iron - Determination of nitrogen content -- Titrimetric method after distillation Acier et fonte - Dosage de I'azote - Méthode titrimétrique apres distillation Reference number ISO10702:1993(E) No reproduction or networking permitted without license from IHS Not for Resale ISO 10702:1993(E) Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (IsO member bodies). The work of preparing International Standards is normally carried out through IsO technical committees. Each member body interested in a subject for represented on that committee. International organizations, governmental and non-governmental, in liaison with IsO, also take part in the work. iso collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 10702 was prepared by Technical Committee ISO/TC 17. Steel, Sub-Committee SC 1, Methods of determination of chemicalcomposition. Annex A forms an integral part of this International Standard. Annexes B and C are for information only. ISO1993 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, eltectronic or mechanical, including photocopying and microfilm, without per- mission in writing from the publisher. International Organization for Standardization Case Postale56.CH-1211Geneve20·Switzerland Printed in Switzerland permitted without license from IHS Not for Resale ISO 10702:1993(E) INTERNATIONAL STANDARD Steel and iron -- Determination of nitrogen content - Titrimetric method after distillation 1 Scope 3 Principle This International Standard specifies a method for the Dissolution of a test portion in hydrochloric acid fol- determination of nitrogen in steel and iron, finishing lowed by oxidation with hydrogen peroxide. with a titration. Fuming of the acid-insoluble residue in sulfuric acid The method is applicable to nitrogen contents from with potassium sulfate and copper(ll) sulfate. 0,002 % (m/m) to 0,5 % (m/m). However, the 'method Distillation of the solution made alkaline with sodium is not applicable to samples containing silicon nitride. hydroxide, and collection of ammonia in a receiver containing orthoboric acid solution. Titration of the ammonium ion with amidosulfuric acid. 2 Normative references 4 Reagents The following standards contain provisions which. through reference in this text, constitute provisions During the analysis, unless otherwise stated, use only ofthisInternationalStandard.Atthetime.of publica- reagents of recognized analytical grade and only tion, the editions indicated were valid. All standards freshly prepared grade 2 water as specified in are subject to revision, and parties to agreements ISO 3696. based on this International Standard. are encouraged to investigate the possibility of applying the most re- cent editions of 'the standards indicated below. 4.1 Potassium sulfate. Members of IEC and ISO maintain registers of cur- 4.2 Copper(1l) sulfate pentahydrate, CuSO4.5H20 rentlyvalid International Standards. ISO 377-2:1989, Selection and preparation of samples 4.3 Hydrochloric acid, p about 1,19 g/ml, diluted andtestpiecesofwroughtsteels- -Part 2:Samples 1 + 1. for the determination of the chemical composition. 4.4 Sulfuric acid, p about 1,84 g/ml. IsO 385-1:1984, Laboratory glassware --- Burettes Part 1: General requirements. 4.5 Orthoboric acid, 1 g/l solution. IsO 648:1977, Laboratory glassware One-mark Dissolve 1 g of orthoboric acid (HgBO3) in water and pipettes. dilute to 1 litre. Iso 1042:1983, Laboratory glassware -- One-mark 4.6 Orthoboric acid, 5 g/l solution. volu