ISO INTERNATIONAL STANDARD 10720 Firstedition 1997-08-15 Steel and iron - Determination of nitrogen content - Thermal conductimetric method after fusion in a current of inert gas Aciers et fontes -- Dosage de I'azote - Methode par conductibilite thermique apres fusion sous un courant de gaz inerte ISO Reference number ISO10720:1997(E) CopyrightIntemationalOrganizationforStandardization No reproduction or networking permited without license from IHS Not for Resale ISO10720:1997(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 which a technical committee has been established has the right to be 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 (lEC)onallmattersofelectrotechnicaistandardization. DraftInternationalStandardsadopted by thetechnical committeesare circulated to the member bodies for voting. Publication as an International a vote. International Standard isO 10720 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 1, Methods of determination of chemicalcomposition. AnnexesAtoCofthisInternationalStandardareforinformationonly. @ISO1997 All rights reserved. Unless otherwise specified, 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. InternationalOrganizationforStandardization Casepostale56.CH-1211Geneve20Switzerland Internet [email protected] X.400 C=ch; a=400net; p=iso; o=isocs; S=central Printed in Switzerland ii Copyright Intern No reproduction or networking permitted without lic cense from IHS Not for Resale ISO 10720:1997(E) INTERNATIONAL STANDARD ISO Steel and iron Determination of nitrogen content Thermal conductimetric method after fusion in a current of inert gas 1 Scope This International Standard specifies a thermal conductimetric method after fusion under inert gas for the determination of nitrogen in steel and iron. The method is applicable to nitrogen contents between 0,000 8 % (m/m) and 0,5% (m/m). 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. Iso 385-1:1984, Laboratory glassware— Burettes Part 1: General requirements. Iso 648:1977, Laboratory glassware - One-mark pipettes. Iso 1042:—1), Laboratory glassware -- One-mark volumetric flasks. Iso 3696:1987, Water for analytical laboratory use - --- Specification and test methods. IsO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results -- Part 1: General principles and definitions. Iso 5725-2:1994, Accuracy (trueness and precision) of measurement methods and results -- Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method. Iso 5725-3:1994, Accuracy (trueness and precision) of measurement methods and results - Part 3: Intermediate measures of the precision of a standard measurement method. Iso 14284 :1996, Steel and iron - Sampling and preparation of samples for the determination of chemical composition. 3 Principle Fusion of a test portion in a single-use graphite crucible under helium gas at a high temperature (e. g. 2 200 °C) Extraction of the nitrogen in the form of molecular nitrogen in the stream of helium. Separation from the o