ISO INTERNATIONAL STANDARD 4935 First edition 1989-09-15 Corrected and reprinted 1990-02-01 Steel and iron - Determination of sulfur content - Infrared absorption method after combustion in an induction furnace Aciers et fontes - Dosage du soufre - Methode par absorption dans I'infrarouge aprescombustiondansunfourainduction Reference number ISO4935:1989 (E) No reproduction or networking permited without license from IHS Not for Resale ISO 4935 : 1989 (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 normallycarried outthroughIsotechnical committees.Each member bodyinterested inasubjectforwhichatechnical committeehasbeenestablishedhas the right to be represented on that committee. International organizations, govern- mental 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 approval before their acceptance as International Standards by the ISo Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 4935 was prepared by Technical Committee ISO/TC 17, Steel. Annexes A, B and C of this International Standard are for information only. ? ISO 1989 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher International OrganizationforStandardization Case postale 56 . CH-1211 Geneve 20 . Switzerland Printed in Switzerland Copyright International Organization for Standardization No reproduction or networking permitted without license from IHS Not for Resale ISO4935:1989 (E) INTERNATIONAL STANDARD Steel and iron - Determination of sulfur content Infrared absorption method after combustion in an induction furnace 1 Scope 4 Reagents and materials This International Standard specifies an infrared absorption Duringtheanalysis,unless otherwisestated,use onlyreagents method after combustion in an induction furnace for the deter- of recognized analytical grade and only distilled water or water mination of sulfur content in steel and iron. of equivalent purity. The method is applicable to sulfur contents between 4.1 Oxygen, 99,5 % (m/m) minimum. 0002%(m/m)and0,10%(m/m) An oxidation catalyst [copper(ll) oxide or platinum] tube heated to a temperature above 450 oC must be used prior to a purify ing unit (see annex C), when the presence of organic con- 2 Normative references taminants is suspected in the oxygen. Thefollowing standards containprovisions which,through 4.2 Pure iron, of known low sulfur contents less than referencein thistext,constituteprovisions of this International 0,000 5 % (m/m). Standard.At the time of publication,the editions indicated were valid.All standards are subject to revision,and parties to agreements based on this International Standard are encour- 4.3 Suitable solvent, appropriate for washing greasy or aged to investigate the possibility of applying the most recent dirty test samples, for example, acetone. editionsof thestandardslistedbelow.Members ofIEC and ISO maintain registers of currently valid International Standards 4.4 Magnesium perchlorate [Mg(CIO4)2], particle size: from 0,7 mm to 1,2 mm. ISo 377 : 1985, Wrought steel -- Selection and preparation of 4.5 Accelerator, tungsten, free of sulfur, or of known suifur samples and test pieces. contents less than 0,000 5 % (m/m). The mesh size of the ac- Iso 385-1 : 1984, Laboratory glassware - Burettes -- Part 1: celerator maybe dependent on the type of apparatus used. General requirements. 4.6 Sulfur, standard sol