BS-6200-3.19.1-1985 ISO-4941-1978.pdf
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1、BRITISH STANDARD BS 6200-3.19.1: 1985 ISO 4941:1978 Sampling and analysis of iron, steel and other ferrous metals Part 3: Methods of analysis Section 3.19 Determination of molybdenum Subsection 3.19.1 Steel and cast iron: photometric method UDC 669.1:543.42.062:546.77 Licensed Copy: sheffieldun shef
2、fieldun, na, Wed Dec 06 14:58:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6200-3.19.1:1985 This British Standard, having been prepared under the direction of the Iron and Steel Standards Committee, was published under the authority of the Board of BSI and comes into effect on 28 February 1985 B
3、SI 09-1999 The following BSI references relate to the work on this standard: Committee reference ISM/18 Draft for approval 84/39008 ISBN 0 580 14268 X National foreword This Subsection of BS 6200 has been prepared under the direction of the Iron and Steel Standards Committee. It is identical with IS
4、O 4941:1978 “Steels and cast irons Determination of molybdenum content Photometric method” published by the International Organization for Standardization (ISO) and supersedes method 1 for the determination of molybdenum in BSI Handbook No. 19. Terminology and conventions. The text of the Internatio
5、nal Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British
6、 Standards it is current practice to use a full point on the baseline as the decimal marker. Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. Cross-reference. The Technical Committee has reviewed the provisions of ISO/R 377, t
7、o which reference is made in clause 6, and has decided that they are acceptable for use in conjunction with this standard. A related standard to ISO/R 377 is BS 1837 “Methods for the sampling of iron, steel, permanent magnet alloys and ferro-alloys”. Appropriate procedures from ISO/R 377 will be inc
8、orporated in BS 6200-2 “Methods of sampling and sample preparation”, which will be published in due course and which will supersede BS 1837. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct applica
9、tion. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date)
10、and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:58:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6200-3.19
11、.1:1985 BSI 09-1999i Contents Page National forewordInside front cover 1Scope and field of application1 2Reference1 3Principle1 4Reagents1 5Apparatus2 6Sampling2 7Procedure2 8Expression of results4 9Test report4 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, We
12、d Dec 06 14:58:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:58:11 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6200-3.19.1:1985 BSI 09-19991 1 Scope and field of application This International Standard specifies a photometric metho
13、d for the determination of the molybdenum content of steels and cast irons. The method is applicable to steels and cast irons having molybdenum contents between 0,003 and 9 % (m/m). Vanadium and tungsten interfere with the measurement if, because of their contents, the V/Mo ratio is greater than 16
14、or the W/Mo ratio is greater than 8. NOTEGreater V/Mo or W/Mo ratios (up to 300) may, however, be permitted, but in such cases it is necessary to carry out the measurement very quickly after the extraction. 2 Reference ISO/R 377, Selection and preparation of samples and test pieces for wrought steel
15、. 3 Principle Dissolution of a test portion in an appropriate mixture of acids and decomposition of the carbides by oxidation. Quantitative formation of a coloured compound of molybdenum, in the presence of thiocyanate, iron(II) and/or copper(II) ions and extraction of this compound using n-butyl ac
16、etate. Photometric measurement of the coloured compound at a wavelength of about 470 nm. NOTEWhen the conditions of the procedure are respected, the coefficient of molecular absorption is 18 930 60. 4 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled w
17、ater or water of equivalent purity. 4.1 Iron, in flake or powder form, with a molybdenum content less than 0,005 % and free from tungsten and vanadium. 4.2 n-Butyl acetate 4.3 Nitric acid, about 1,40 g/ml, about 14 M solution. 4.4 Hydrochloric acid, about 1,19 g/ml, about 12 M solution. 4.5 Hydrochl
18、oric acid, about 9 M solution (3 + 1). 4.6 Hydrochloric acid, about 6 M solution (1 + 1). 4.7 Acid mixture I To 1 volume of the nitric acid (4.3) add 2 volumes of the hydrochloric acid (4.4) and mix well. Prepare the solution immediately before use. 4.8 Acid mixture II Add 150 ml of phosphoric acid,
19、 about 1,70 g/ml, to 300 ml of water, and add this diluted acid to 360 ml of perchloric acid, about 1,67 g/ml. Dilute to 1 000 ml with water and mix. NOTEIn the preparation of this acid mixture, the 360 ml of perchloric acid, about 1,67 g/ml, may be replaced by 150 ml of sulphuric acid, about 1,84 g
20、/ml. 4.9 Ascorbic acid, 100 g/l solution. Prepare this solution at the moment of use. 4.10 Ammonium thiocyanate, 320 g/l solution. Store this solution away from light. 4.11 Copper(II), solution corresponding to 70 mg of Cu(II) per litre in a hydrochloric medium about 1,5 M. Dissolve 0,188 g of coppe
21、r(II) chloride dihydrate (CuCl2.2H2O) or 0,275 g of copper(II) sulphate pentahydrate (CuSO4.5H2O) in 125 ml of the hydrochloric acid (4.4). Make up the volume to 1 000 ml with water and mix. 4.12 Tin(II) copper(II) chloride, solution in a hydrochloric medium about 2 M. Dissolve 80 g of tin(II) chlor
22、ide in 155 ml of the hydrochloric acid (4.4). Add 100 ml of the copper(II) solution (4.11). Make up the volume to 1 000 ml with water and mix. Prepare the solution immediately before use. 4.13 Iron, acidic solution corresponding to 10 g of Fe per litre. Dissolve 10 g of the iron (4.1) in 500 ml of t
23、he acid mixture II (4.8) used for the determination; after cooling, make up the volume to 1 000 ml with water and mix. 4.14 Molybdenum, standard solution corresponding to 500 mg of Mo per litre. Weigh, to the nearest 0,001 g, 1,261 g of sodium molybdate dihydrate (Na2MoO4.2H2O) or 0,920 g of ammoniu
24、m heptamolybdate tetrahydrate (NH4)6Mo7O24.4H2O and dissolve in 500 ml of the hydrochloric acid (4.4). Transfer the solution quantitatively to a 1 000 ml one-mark volumetric flask, dilute to the mark with water and mix. 4.15 Molybdenum, standard solution corresponding to 5 mg of Mo per litre. Transf
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