Steel and iron - Determination of sulphur content - Infrared absorption method after combustion in an induction furnace (ISO 4935:1989)

The method is applicable to sulphur contents between 0,002 % (m/m) and 0,10 % (m/m). Specifies principle, reagents and material, apparatus, sampling, procedure, expression of results and test report. Annex A gives additional information on the international cooperative tests. Annex B represents the precision date graphically. Annex C deals with induction furnaces and infrared sulfur analysers.

Stahl und Eisen - Bestimmung des Schwefelgehalts - Methode mit Infrarotabsorption nach Verbrennung im Induktionsofen (ISO 4935:1989)

Aciers et fontes - Détermination du soufre - Méthode par absorption dans l'infrarouge apres combustion dans un four a induction (ISO 4935:1989)

L'IEC 61811-10:2002 est une spécification intermédiaire applicable aux relais électromécaniques élémentaires (de tout-ou-rien à temps non spécifié) sous assurance de la qualité pour application industrielle.

Jeklo in železo - Določanje žvepla - Infrardeča absorpcijska metoda po zgorevanju v indukcijski peči (ISO 4935:1989)

General Information

Status
Published
Publication Date
30-Apr-1997
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-May-1997
Due Date
01-May-1997
Completion Date
01-May-1997

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Stahl und Eisen - Bestimmung des Schwefelgehalts - Methode mit Infrarotabsorption nach Verbrennung im Induktionsofen (ISO 4935:1989)Aciers et fontes - Détermination du soufre - Méthode par absorption dans l'infrarouge apres combustion dans un four a induction (ISO 4935:1989)Steel and iron - Determination of sulphur content - Infrared absorption method after combustion in an induction furnace (ISO 4935:1989)77.080.01Železne kovine na splošnoFerrous metals in generalICS:Ta slovenski standard je istoveten z:EN 24935:1991SIST EN 24935:1997en01-maj-1997SIST EN 24935:1997SLOVENSKI
STANDARD



SIST EN 24935:1997



SIST EN 24935:1997



SIST EN 24935:1997



INTERNATIONAL STANDARD First edition 1989-09-15 Corrected and reprinted 1990-02-0 1 Steel and iron - Determination of Sulfur content - Infrared absorption method after combustion in an induction furnace Aciers et fontes - Dosage du soufre - IWthode par absorp tion apres combustion dans un four 2 induction dans l’in frarouge Reference number ISO 4935 : 1989 (El SIST EN 24935:1997



PSO4935:1989 (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 normally carried out through ISO technical committees. Esch 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, 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, S teel. Annexes A, B and C of this International Standard are for information only. 0 ISO 1989 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronie or mechanical, including photocopying and microfilm, without Permission in writing from the publisher. International Organization for Standardization Case postale 56 l CH-1211 Geneve 20 l Switzerland Printed in Switzerland SIST EN 24935:1997



INTERNATIONAL STANDARD ISO 4935 : 1989 (E) Steel and iron - Determination of Sulfur content - Infrared absorption method after combustion in an induction furnace 1 Scope This International Standard specifies an infrared absorption method after combustion in an induction furnace for the deter- mination of Sulfur content in steel and iron. The method is applicable to Sulfur contents between 0,002 % Hrn) and 0,lO % (mlm) 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 revision, and Parties to agreements based on this International Standard are encour- aged to investigate the possibility of applying the most recent editions of the Standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 377 : 1985, Wrought steel - Selection and preparation of samples and test pieces. ISO 385-1 : 1984, Laboratory glassware - Burettes - Part 7: General requiremen ts. ISO 648 : 1977, Laboratoy glassware - One-mark pipettes. ISO 1042 : 1983, Laboratoryglassware - One-mark volumetric flasks. ISO 5725 : 1986, Precision of testmethods - Determination of repeatability and reproducibility for a Standard test method by in ter-labora tory tes ts. 3 Principle Combustion of a test Portion with accelerator at a high temperature in a high-frequency induction furnace in a current of pure Oxygen. Transformation of Sulfur into Sulfur dioxide. Measurement by infrared absorption of the Sulfur dioxide carried by a current of Oxygen. 4 Reagents and materials During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.1 Oxygen, 99,5 % (mlm ) minimum. An Oxidation catalyst LcopperUl) Oxide or platinuml 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- taminants is suspected in the Oxygen. 4.2 Pure iron, of known low Sulfur contents less than 0,000 5 % hlm). 4.3 Suitable solvent, appropriate for washing greasy or dirty test samples, for example, acetone. 4.4 Magnesium perchlorate [MgK104)21, particle size: from 0,7 mm to 1,2 mm. 4.5 Accelerator, tungsten, free of Sulfur, or of known Sulfur contents less than 0,000 5 % (mlm). The mesh size of the ac- celerator may be dependent on the type of apparatus used. 4.6 Sulfur, Standard solutions. Weigh, to the nearest 0,l mg, the mass described in table 1 of potassium sulfate [minimum assay: 99,9 % (mlm)] previously dried at 105 OC to 110 OC for 1 h or to constant mass and cooled in a desiccator. Table 1 Reference of Sulfur Standard solution Mass of potassium sulfate 4.6.1 4.6.2 4.6.3 4.6.4 4.6.5 4.6.6 4.6.7 0,217 4 0,380 4 0934 1,086 9 1,902 2 2,717 2 4,347 5 Concentration of Sulfur mg/ml -7 0,40 0,70 l,oo 2,00 3,50 5,00 8,00 SIST EN 24935:1997



ISO4935:1989 (El Transfer to seven 100 ml beakers and dissolve in water. cent flow rate whilst on standby. Maintain a glass wool filter or a stainless steel net as a dust collector. Clean and Change as necessary. The furnace chamber, pedestal post and filter trap shall be cleaned frequently to remove Oxide build-up. Transfer quantitatively into seven 100 ml one-mark flasks. D ilute to the mark with water and mix. volumetric Allow each item of equipment to stabilize for the time recom- mended by the equipment manufacturers when the main supply is switched on after being out of action for any length of time. 4.7 Inert cera mit (attapulgus clay) sodium hyd roxide ’ particle size: from 0’7 impregnated mm to 1’2 mm. with 5 Apparatus After cleaning the furnace chamber and/or changing filters or after the equipment has been inoperative for a period, stabilize the apparatus by burning several samples of similar type to the samples to be analysed Prior to setting up for analysis. Duri ng the analysis, u labo iratory apparatus. nless otherwise stated, use only ordinary All volumetric glassware shall be class A, in accordance with ISO 385-1, ISO 648 or ISO 1042 as appropriate. Flush Oxygen th rough the apparatus controls to give a zero reading. and adjust the instrument The apparatus required for combustion in a high-frequency induction furnace and the subsequent infrared absorption measurement of the evolved Sulfur dioxide may be obtained commercially from a number of manufacturers. Follow the manufacturer’s instructions for the Operation of the equipment. If the instrument used provides a direct reading in percentage Sulfur, adjust the instrument reading for each calibration range as follows. Select the certified reference material with a Sulfur content close to the maximum Sulfur content in the calibration series, measure the Sulfur content of the certified reference material in the same manner as specified in 7.4. Features of commercial instruments are given in annex C. 5.1 Micropipettes, less than 1 ~1. 50 pl and 100 ~1, limit of error shall be Adjust the reading of the instrument to the certified value. NOTE - This adjustmen t shall be made before the calibration as specif ied in 7.5. It cannot replace or correct the calibration. 5.2 Tin capsule, about 6 mm in diameter, 18 mm in height, 0’3 g in mass and approximately 0’4 ml in volume. 7.2 Test Portion 5.3 Ceramic crucible in an induction furnace. capable of withstand ing comb ustion Degrease the test Sample bY washing in a suitable solvent (4. Evaporate the last traces of the washing liquid by heating. 3). Ignite crucibles in an electric furnace in air or in a current of Oxygen for not less than 2 h at 1 100 OC and store in a desic- cator before use. Weigh, to the nearest 1 mg, 1 g of the test Sample for Sulfur contents less than 0’04 % (mlm) and 0’5 g for Sulfur contents greater than 0’04 % (mlm). NOTE - For the determination of low Sulfur contents ignite crucibles a t 1 350 OC in a current of Oxygen. it is advisable to NOTE - The mass instrument used. of the test Portion may be dependent on the type of 6 Sampling 7.3 Blank test Sampling shall be carried out in accordance with ISO 377 or appropriate national Standards for iron. Prior to the duplicate. determination, carry out the following blank tests in 7 Procedure Transfer a tin capsule (5.2) to a ceramic crucible (5.31, press the tin capsule lightly against the bottom of the crucible. Add the same quantity of the pure iron (4.2) as the test Portion (7.2) and 1’5 g + 0’1 g of the accelerator (4.5). SAFETY INSTRUCTIONS - The risks related to combus- tion analysis are mainly burns in pre-igniting the ceramic crucibles and in the fusions. Use crucible tongs at all times and suitable Containers for the used crucibles. Nor- mal precautions for handling Oxygen cylinders shall be taken. Oxygen from the combustion process shall be removed effectively from the apparatus since a high con- centration of Oxygen in a confined space tan present a fire hazard. Treat the crucible and contents third Paragraphs of 7.4. as specif ied in the second and Obtain the readings of the blank tests and convert them to milligrams of Sulfur by means of the calibration graph (7.5). The blank value is obtained by subtracting the mass of Sulfur in the pure iron (4.2) used (sec note 1) from the mass of Sulfur in the blank tests. 7.1 Apparatus conditioning Purify the Oxygen supply using tubes packed with the inert ceramic (attapulgus clay) impregnated with sodium hydroxide (4.7) and magnesium perchlorate (4.4)’ and maintain a quies- The mean blank value values (sec note 2). - (ml) is calculated from the two blank 2 SIST EN 24935:1997



Iso4935:1989 (El NOTES 7.5.1.2 Measurements 1 Determine the Sulfur content in the pure iron (4.2) as follows. Prepare two ceramic crucibles (5.3). Transfer a tin capsule (5.2) to each and press the capsule lightly against the bottom of the crucible. Add 0,500 g of the pure iron (4.2) to one ceramic crucible and 1,000 g to the other. Cover each with i,5 g + 0,l g of the accelerator (4.5). Treat the crucible and contents as specified in the second and third Paragraphs of 7.4. Convert the values obtained into milligrams of Sulfur by means of the calibration graph (7.5). The mass (m2) of Sulfur with 0,500 g of pure iron added, is obtained by subtracting the value (ms) corresponding to 0,500 g of the pure iro
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