1、BRITISH STANDARD BS 6200-3.18.4: 1991 Sampling and analysis of iron, steel and other ferrous metals Part3: Methods of analysis Section3.18 Determination of manganese Subsection3.18.4 Steel and cast iron:volumetric methodBS6200-3.18.4:1991 This British Standard, having been prepared under the directi
2、onof the Iron and Steel Standards Policy Committee, waspublished under the authorityof the Standards Boardand comes into effect on 29November1991 BSI09-1999 The following BSI references relate to the work on this standard: Committee reference ISM/18 Draft for comment91/35215DC ISBN 0 580 19944 4 Com
3、mittees responsible for this British Standard The preparation of this British Standard was entrusted by the Iron and Steel Standards Policy Committee (ISM/-) to Technical Committee ISM/18, upon which the following bodies were represented: BCIRA British Steel Industry Department of Trade and Industry
4、 (Laboratory of the Government Chemist) Ferro Alloys and Metals Producers Association Ministry of Defence Amendments issued since publication Amd. No. Date CommentsBS6200-3.18.4:1991 BSI 09-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Principle 1 3 Reagents
5、1 4 Apparatus 1 5 Sampling 1 6 Procedure 1 7 Calculation and expression of results 2 8 Test report 3 Table 1 Precision data 3 Table 2 Values for inter-laboratory agreement 3 Publication(s) referred to Inside back coverBS6200-3.18.4:1991 ii BSI 09-1999 Foreword This Subsection of BS6200 has been prep
6、ared under the direction of the Iron and Steel Standards Policy Committee and supersedes method1 for the determination of manganese in BSI Handbook No.19, to which it is technically equivalent. BS6200 is a multipart British Standard, covering all aspects of the sampling and analysis of iron, steel a
7、nd other ferrous metals. A list of contents, together with general information, is given in Part1. A British Standard 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 d
8、oes not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This
9、 will be indicated in the amendment table on the inside front cover.BS6200-3.18.4:1991 BSI 09-1999 1 1 Scope This Subsection of BS6200 describes a volumetric method for the determination of manganese in steel and cast iron. The method is applicable to manganese contents from0.02%(m/m) to14%(m/m). NO
10、TEThe titles of the publications referred to in this Subsection of BS6200 are listed on the inside back cover. 2 Principle From an oxidized sulfuric acid solution of the sample, iron and chromium are separated with zinc oxide. Manganese is oxidized to permanganate with ammonium peroxodisulfate in th
11、e presence of a silver catalyst. Residual peroxodisulfate is destroyed by boiling and the determination completed by titration with diammonium iron(II) sulfate and potassium dichromate. 3 Reagents During the analysis, use only reagents of recognized analytical grade and only grade3 water as specifie
12、d in BS3978. 3.1 Diammonium iron(II) sulfate,40g/L. Dissolve40g of diammonium iron(II) sulfate, (NH 4 ) 2 SO 4 . FeSO 4 .6H 2 O, in a mixture of500mL of water and20mL of sulfuric acid, density =1.84g/mL, and cool. Transfer to a 1L volumetric flask, dilute to the mark and mix. 3.2 Ammonium peroxodisu
13、lfate,125g/L solution. Dissolve25g of ammonium peroxodisulfate (NH 4 ) 2 S 2 O 8 , in water, dilute to200mL and mix. 3.3 Hydrochloric acid, =1.16g/mL to1.18g/mL. 3.4 Nitric acid, =1.42g/mL. 3.5 Phosphoric-sulfuric acid mixture. To600mL of water add cautiously150mL of orthophosphoric acid, =1.75g/mL,
14、150mL of sulfuric acid, =1.84g/mL, and mix. Cool, dilute to1L andmix. 3.6 Potassium dichromate, standard solution. Dissolve4.9035g of potassium dichromate, K 2 Cr 2 O 7 , (previously dried to constant weight at150 C) in approximately500mL of water. Cool, transfer to a1L volumetric flask, dilute to t
15、he mark and mix.1mL of this solution is equivalent to1.1mg of manganese. 3.7 Silver nitrate,10g/L solution. Dissolve5g of silver nitrate in water, dilute to500mL and mix. 3.8 Sodium N-phenylsulfanilate, preoxidized, (sodium diphenylaminesulfonate). Use pellets containing the equivalent of1mg of preo
16、xidized sodium N-phenylsulfanilate, or a suitable solution containing the same equivalent of preoxidized sodium N-phenylsulfanilate. 3.9 Sulfuric acid. To400mL of water add cautiously150mL of sulfuric acid, =1.84g/mL. Mix, cool, dilute to1L and mix. 3.10 Sulfurous acid. Pass sulfur dioxide gas into1
17、00mL of water until a saturated solution is obtained. 3.11 Zinc oxide suspension. Add50g of finely powdered zinc oxide to200mL of water and stir or shake until a smooth cream is obtained. Thesuspension should be stirred immediately before use, and also between additions during use. 4 Apparatus 4.1 O
18、rdinary laboratory apparatus 4.2 Filter papers. Medium fast qualitative24cm fluted filter papers. NOTEWhatman No. 2V or equivalent have been found satisfactory. 4.3 Volumetric glassware, in accordance with classA of BS846, BS1583 or BS1792, as appropriate. 5 Sampling Carry out sampling in accordance
19、 with BS1837. NOTEBS6200-2, which will supersede BS1837, is currently in preparation. On its publication this Subsection will be amended to include sampling in accordance with BS6200-2. 6 Procedure 6.1 Test portion Weigh, to the nearest0.001g, a test portion of2.2g. When the manganese content exceed
20、s2.75%(m/m), reduce the mass of the test portion so that the manganese content of the final solution (see6.2.3) does not exceed30mg. 6.2 Determination 6.2.1 Preparation of the test solution Place the test portion in a650mL conical beaker. Add70mL of sulfuric acid(3.9), cover the beaker and heat unti
21、l solvent action ceases. If dissolution is incomplete, for example in the case of high nickel stainless steel or heat-resisting steel, make additions of both hydrochloric acid(3.3) and nitric acid(3.4) to facilitate solution. If initial acid attack leaves large residues of acid-resistant carbide, fo
22、r example with certain types of high carbon chromium steels, evaporate the sulfuric acid solution until fumes appear. Cool, redissolve in water, oxidize with nitric acid(3.4), and proceed to6.2.2.BS6200-3.18.4:1991 2 BSI 09-1999 Oxidize with nitric acid(3.4) but do NOT oxidize stainless steel types
23、until solution is complete unless hydrochloric acid is already present or is added to the solution. Evaporate until fumes appear, then cool. If hydrochloric acid has been added to facilitate solution, dissolve the salts in water, and repeat the evaporation to fumes. Add150mL of water, five drops of
24、sulfurous acid(3.10) and heat until soluble salts are dissolved. Cool to room temperature. If substantial amounts of tungstic acid or graphite are present at this stage, filter through a paper-pulp pad, wash with a small amount of cold sulfuric acid(3.9) and discard the residue. 6.2.2 Separation of
25、iron and chromium Add zinc oxide suspension(3.11) approximately5mL at a time, mixing thoroughly after each addition, until the solution is neutralized and a faint permanent precipitate of iron-group hydroxides is obtained. Then make a final addition of10mL of zinc oxide suspension(3.11) to complete
26、the precipitation, indicated by a definite change from a clear dark-coloured solution to a turbid brown solution due to the precipitation of hydroxides. The addition of the10mL excess of zinc oxide suspension causes the brown precipitate to assume a slightly milky white appearance. Add35mL of silver
27、 nitrate solution(3.7), mix thoroughly, transfer to a500mL volumetric flask, and dilute to the graduation mark. Make a correction for the volume occupied by the precipitated hydroxides and the excess of zinc oxide by adding2.5mL of water per1g of test portion plus an allowance of0.5mL for the zinc o
28、xide present, e.g.for a2.2g test portion the addition would be5.5+0.5 =6mL. Mix thoroughly and allow to stand for5min. Take an aliquot by filtration through a dry medium fast texture24cm fluted filter paper(4.2) into a250mL volumetric flask. Rinse the flask with the first few millilitres of filtrate
29、 before collecting the aliquot. 6.2.3 Oxidation and titration of manganese Transfer the aliquot to a650mL conical beaker and add60mL of phosphoric-sulfuric acid mixture(3.5). Add a few glass beads, heat to boiling, add cautiously20mL of ammonium peroxodisulfate(3.2), boil the solution for precisely1
30、5min, and cool rapidly to room temperature. Titrate with diammonium iron(II) sulfate solution(3.1) until an excess of at least2mL is present. Add preoxidized sodium N-phenylsulfanilate indicator(3.8) and titrate with potassium dichromate solution(3.6) until one drop produces a deep violet coloured e
31、nd point. Record the volumes of titrants used. 6.2.4 Standardization of diammonium iron(II) sulfate solution Transfer60mL of phosphoric-sulfuric acid mixture(3.5) to a650mL conical beaker, dilute to300mL and add preoxidized sodium N-phenylsulfanilate indicator(3.8). Add three drops of diammonium iro
32、n(II) sulfate solution(3.1) and then add potassium dichromate solution(3.6) until one drop produces a deep violet colour. By means of a pipette or burette, add exactly25mL of diammonium iron(II) sulfate solution(3.1) and titrate with potassium dichromate solution(3.6) until one drop produces a deep
33、violet end point. Record the volume of potassium dichromate solution(3.6) used between the two endpoints. 7 Calculation and expression of results 7.1 Calculation Calculate the factor F of the diammonium iron(II) sulfate solution(3.1) from the equation: F =V f /25 where V fis the volume, of potassium
34、 dichromate standard solution(3.6) used in6.2.4 in the titration between the two end points (in mL). NOTE1mL of potassium dichromate solution(3.6) is equivalent to1.1mg of manganese. Calculate the manganese content Mn expressed as a percentage by mass from the equation: where V 1 is the volume of di
35、ammonium iron(II) sulfate solution(3.1) used in6.2.3 (inmL); V 2 is the volume of potassium dichromate solution(3.6) used in6.2.3 (inmL); m is the mass of the test portion in6.1 (ing). Mn 0.220 FV 1 V 2 () m - =BS6200-3.18.4:1991 BSI 09-1999 3 7.2 Precision 7.2.1 Precision data A planned trial of th
36、is method was carried out by9 to10 laboratories on each of12 samples. The mean results for each laboratory given in the original report 1)have been examined statistically to obtain values for between-laboratory agreement. In the absence of individual results it is not possible to calculate repeatabi
37、lity, r, or reproducibility, R, as defined in BS5497-1. From the reported results, for probability P =95%, the statistical limits(2.83s) for agreement between laboratory means have been calculated and are given in Table 1. The difference between the mean results of two laboratories found on identica
38、l test material will exceed the P =95% agreement level not more that once in20 cases, on average, in the normal and correct operation of the method. Table 1 Precision data 7.2.2 Regression data Statistical analysis of the results showed a logarithmic relationship between manganese content and the va
39、lue of the standard deviation of the laboratory means summarized by the equation: log s =0.3204log Mn%1.8192 correlation0.831 The predicted values for the statistical limits for agreement between two laboratories at P =95% calculated from the equation are given in Table 2. Table 2 Values for inter-l
40、aboratory agreement (2.83s, P =95%) 8 Test report The test report shall include the following information: a) all information necessary for the identification of the sample, the laboratory and the date of analysis; b) the method used, by reference to this Subsection of BS6200; c) the results, and th
41、e form in which they are expresed; d) any unusual features noted during the determination; e) any operation not specified in this BritishStandard or any optional operation which may have influenced the results. 1) Methods of Analysis Committee. The determination of silicon and manganese in iron and
42、steel. Metallurgia, October1948,347-352. Type of steel or alloy Manganese content Between-laboratory agreement 2.83s 80%Ni,20%Cr alloy %(m/m) 0.112 0.016 25%Co magnet alloy 0.129 0.026 18%W,4%Cr, 1%V steel 0.282 0.042 1.5%C,14%Cr, 2.5%Co steel 0.400 0.035 14% Cr,0.1%Zr steel 0.467 0.028 18%Cr,8%Ni,
43、1.5%Ti,1%Al 0.644 0.029 35%Co magnet alloy 0.695 0.025 25%Cr,20%Ni steel 0.937 0.040 0.5%Si basic iron 1.09 0.058 2.5%Si haematite iron 1.42 0.057 18%Cr,8%Ni, 1.5%Mn steel 1.54 0.062 18%Cr,9%Mn steel 9.20 0.077 13.5%Mn steel (four laboratories) 13.45 0.36 Manganese 95% inter-laboratory agreement % (
44、m/m) 0.10 0.20 0.5 1.0 2.0 5.0 10.0 0.021 0.026 0.034 0.043 0.054 0.072 0.0904 blankBS6200-3.18.4:1991 BSI 09-1999 Publication(s) referred to BS846, Specification for burettes. BS1583, Specification for one-mark pipettes. BS1792, Specification for one-mark volumetric flasks. BS1837, Methods for the
45、sampling of iron, steel, permanent magnet alloys and ferro-alloys. BS3978, Specification for water for laboratory use. BS5497, Precision of test methods. BS5497-1, Guide for the determination of repeatability and reproducibility for a standard test method by inter-laboratory tests. BS6200, Sampling
46、and analysis of iron, steel and other ferrous metals. BS6200-1, Introduction and contents 2) . BS6200-2, Methods of sampling and sample preparation 3) . BSI Handbook No.19, Methods for the sampling and analysis of iron, steel and other ferrous metals 2) . 2) Referred to in the foreword only. 3) In p
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