1、BRITISH STANDARD BS 6200-3.28.2: 1990 EN 24935:1991 ISO 4935:1989 Incorporating Amendment No. 1 Sampling and analysis of iron, steel and other ferrous metals Part 3: Methods of analysis Section 3.28 Determination of sulphur Subsection 3.28.2 Steel and cast iron: infra-red absorption method after com
2、bustion in an induction furnace The European Standard EN 24935:1991 has the status of a British StandardBS6200-3.28.2:1990 This British Standard, having been prepared under the directionof the Iron and Steel Standards Policy Committee, waspublished under the authorityof the Board of BSI andcomes int
3、o effect on 31August1990 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference ISM/18 Draft for comment87/43477 DC ISBN 0 580 18429 3 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Iron and St
4、eel Standards Policy Committee (ISM/-) to Technical Committee ISM/18, upon which the following bodies were represented: BCIRA British Forging Industry Association British Steel Industry Department of Trade and Industry (Laboratory of the Government Chemist) Ferro Alloys and Metals Producers Associat
5、ion Ministry of Defence Amendments issued since publication Amd. No. Date Comments 7080 February 1992 Indicated by a sideline in the marginBS6200-3.28.2:1990 BSI 08-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 1 Scope 3 2 Normative references 3 3 Pri
6、nciple 3 4 Reagents and materials 3 5 Apparatus 3 6 Sampling 4 7 Procedure 4 8 Expression of results 6 9 Test report 6 Annex A (informative) Additional information on the international cooperative tests 7 Annex B (informative) Graphical representation of precision data 8 Annex C (informative) Featur
7、es of commercial high-frequency induction furnaces and infrared sulfur analysers 8 Figure B.1 Logarithmic relationship between sulfur content % (m/m) and repeatability (r) or reproducibility (R and R w ) 8 Table 1 3 Table 2 5 Table 3 5 Table 4 5 Table 5 6 Table A.1 7 Publication referred to Inside b
8、ack coverBS6200-3.28.2:1990 ii BSI 08-1999 National foreword This Subsection of BS6200has been prepared under the direction of the Iron and Steel Standards Policy Committee. It is identical with ISO4935:1989 “Steel and iron Determination of sulfur content Infrared absorption method after combustion
9、in an induction furnace”, published by the International Organization for Standardization (ISO). In 1991the European Committee for Standardization (CEN) accepted ISO4935:1989as European Standard EN24935:1991. The Technical Committee has reviewed the provisions of ISO377, ISO385-1and ISO648, to which
10、 reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. Related British Standards for ISO377:1985, ISO385-1:1984 and ISO648:1977are, respectively, BS1837:1970“Methods for the sampling of iron, steel, permanent magnet alloys and ferro-alloys
11、”, BS 846:1985 “Specification for burettes” and BS 1583:1986 “Specification for one-mark pipettes”. Appropriate procedures from ISO377will be incorporated in BS6200-2 “Methods of sampling and sample preparation”, which will be published in due course and which will supersede BS1837. A British Standa
12、rd does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International standard Corresponding Bri
13、tish Standard ISO 1042:1983 BS 1792:1982 Specification for one-mark volumetric flasks (Identical) BS 5497 Precision of test methods ISO 5725:1986 Part 1:1987 Guide for the determination of repeatability and reproducibility for a standard test method by inter-laboratory tests (Identical) Summary of p
14、ages This document comprises a front cover, an inside front cover, pages i and ii, theEN title page, pages 2 to 10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on th
15、e inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 24935 December 1991 UDC 669.1:669.14:620.1:543.422.4:546.22 Descriptors: Steels, cast iron, chemical analysis, determination of content, sulphur, infrared spectroscopy, combustion analysis, induction furnaces English version S
16、teel and cast iron Determination of sulfur content Infrared absorption method after combustion in an induction furnace (ISO 4935:1989) Aciers et fontes Dtermination du soufre Mthode par absorption dans linfrarouge aprs combustion dans un four induction (ISO4935:1989) Stahl und Eisen Bestimmung des S
17、chwefelgehalts Methode mit Infrarotabsorption nach Verbrennung im Induktionsofen (ISO4935:1989) This European Standard was approved by CEN on 1991-12-20 and is identical to the ISO standard as referred to. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the
18、conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in t
19、hree official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards organizati
20、ons of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secr
21、etariat: rue de Stassart 36, B-1050 Brussels CEN 1991 Copyright reserved to all CEN members Ref. No. EN 24935:1991 EEN 24935:1991 BSI 08-1999 2 Foreword On the proposal of the Technical Committee ECISS/TC20the Coordinating Commission (COCOR) of the European Committee for Iron and Steel Standardizati
22、on (ECISS) decided in May1991to submit the International Standard ISO 4935:1989, Steel and cast iron Determination of sulfur content Infrared absorption method after combustion in an induction furnace. to the Formal Vote. This European Standard was adopted by CEN on1991-12-20. According to the CEN/C
23、ENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Statement The text of th
24、e International Standard ISO4935:1989was approved by CEN as a European Standard without any modifications.EN 24935:1991 BSI 08-1999 3 1 Scope This International Standard specifies an infrared absorption method after combustion in an induction furnace for the determination of sulfur content in steel
25、and iron. The method is applicable to sulfur contents between0,002% (m/m) and0,10% (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 w
26、ere valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged 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 Internationa
27、l Standards. ISO 377:1985, Wrought steel Selection and preparation of samples and test pieces. ISO 385-1:1984, Laboratory glassware Burettes Part 1: General requirements. ISO 648:1977, Laboratory glassware One-mark pipettes. ISO 1042:1983, Laboratory glassware One-mark volumetric flasks. ISO 5725:19
28、86, Precision of test methods Determination of repeatability and reproducibility for a standard test method by inter-laboratory tests. 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
29、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 Oxy
30、gen,99,5% (m/m) minimum. An oxidation catalyst copper(II) oxide or platinum tube heated to a temperature above450 C must be used prior to a purifying unit (seeAnnex C), when the presence of organic contaminants is suspected in the oxygen. 4.2 Pure iron, of known low sulfur contents less than0,0005%
31、(m/m). 4.3 Suitable solvent, appropriate for washing greasy or dirty test samples, for example, acetone. 4.4 Magnesium perchlorate Mg(ClO 4 ) 2 , particle size: from0,7mm to1,2mm. 4.5 Accelerator, tungsten, free of sulfur, or of known sulfur contents less than0,0005% (m/m). The mesh size of the acce
32、lerator may be dependent on the type of apparatus used. 4.6 Sulfur, standard solutions. Weigh, to the nearest0,1mg, the mass described inTable 1 of potassium sulfate minimum assay:99,9% (m/m) previously dried at105 C to110 C for1h or to constant mass and cooled in a desiccator. Table 1 Transfer to s
33、even100ml beakers and dissolve in water. Transfer quantitatively into seven100ml one-mark volumetric flasks. Dilute to the mark with water and mix. 4.7 Inert ceramic (attapulgus clay) impregnated with sodium hydroxide, particle size: from0,7mm to1,2mm. 5 Apparatus During the analysis, unless otherwi
34、se stated, use only ordinary laboratory apparatus. All volumetric glassware shall be class A, in accordance with ISO385-1, ISO648 or ISO1042as appropriate. The apparatus required for combustion in a high-frequency induction furnace and the subsequent infrared absorption measurement of the evolved su
35、lfur dioxide may be obtained commercially from a number of manufacturers. Follow the manufacturers instructions for the operation of the equipment. Features of commercial instruments are given inAnnex C. 5.1 Micropipettes, 504l and1004l, limit of error shall be less than14l. 5.2 Tin capsule, about6m
36、m in diameter, 18mm in height,0,3g in mass and approximately0,4ml in volume. Reference of sulfur standard solution Mass of potassium sulfate g Concentration of sulfur mg/ml 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 0,543 4 1,086 9 1,902 2 2,717 2 4,347 5 0,40 0,70 1,00 2,00 3,50 5,00
37、 8,00EN 24935:1991 4 BSI 08-1999 5.3 Ceramic crucible, capable of withstanding combustion in an induction furnace. Ignite crucibles in an electric furnace in air or in a current of oxygen for not less than2h at1100 C and store in a desiccator before use. NOTEFor the determination of low sulfur conte
38、nts it is advisable to ignite crucibles at1350 C in a current of oxygen. 6 Sampling Sampling shall be carried out in accordance with ISO377or appropriate national standards for iron. 7 Procedure SAFETY INSTRUCTIONS The risks related to combustion analysis are mainly burns in pre-igniting the ceramic
39、 crucibles and in the fusions. Use crucible tongs at all times and suitable containers for the used crucibles. Normal precautions for handling oxygen cylinders shall be taken. Oxygen from the combustion process shall be removed effectively from the apparatus since a high concentration of oxygen in a
40、 confined space can present a fire hazard. 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 quiescent flow rate whilst on standby. Maintain a glass w
41、ool 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. Allow each item of equipment to stabilize for the time recommended by the equipment manufacturers when the
42、main supply is switched on after being out of action for any length of time. 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
43、setting up for analysis. Flush oxygen through the apparatus and adjust the instrument controls to give a zero reading. 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 w
44、ith 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 in7.4. Adjust the reading of the instrument to the certified value. NOTEThis adjustment shall be made before the calibrat
45、ion as specified in7.5. It cannot replace or correct the calibration. 7.2 Test portion Degrease the test sample by washing in a suitable solvent (4.3). Evaporate the last traces of the washing liquid by heating. Weigh, to the nearest1mg,1g of the test sample for sulfur contents less than0,04% (m/m)
46、and0,5g for sulfur contents greater than0,04% (m/m). NOTEThe mass of the test portion may be dependent on the type of instrument used. 7.3 Blank test Prior to the determination, carry out the following blank tests in duplicate. Transfer a tin capsule (5.2) to a ceramic crucible(5.3), press the tin c
47、apsule lightly against the bottom of the crucible. Add the same quantity of the pure iron (4.2) as the test portion (7.2) and1,5g 0,1g of the accelerator (4.5). Treat the crucible and contents as specified in the second and third paragraphs of7.4. Obtain the readings of the blank tests and convert t
48、hem 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 (see note1) from the mass of sulfur in the blank tests. The mean blank valueis calculated from the two blank values (see note2). NOTE 1Determ
49、ine 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. Add0,500g of the pure iron (4.2) to one ceramic crucible and1,000g to the other. Cover each with1,5g 0,1g of the accelerator (4.5). Treat the crucible and contents as specified in the second and third paragraphs of7.4. Convert the values obtained into milligrams of sulfur by means of the calibration graph (7.5). The
