1、BRITISH STANDARD BS 6200-3.26.3: 1987 EN 24829-1: 1990 ISO 4829-1: 1986 Incorporating Amendment No.1 Sampling and analysis of iron, steel and other ferrous metals Part 3: Methods of analysis Section 3.26 Determination of silicon Subsection 3.26.3 Steel and cast iron: Spectrophotometric method for si
2、licon contents from0.05% (m/m) to1.0% (m/m) ISO title: Steel and cast iron Determination of total silicon content Reduced molybdosilicate spectrophotometric method Part1: Silicon contents between0,05 and1,0% The European Standard EN24829-1:1990 has the status of a British Standard UDC 669.1:543.42:5
3、46.28BS6200-3.26.3:1987 This British Standard, having been prepared under the directionof the Iron and SteelStandards Committee, waspublished under the authorityof the Board of BSIandcomes into effect on 30September1987 BSI 10-1999 The following BSI references relate to the work on this standard: Co
4、mmittee reference ISM/18 Draft for comment85/41149 DC ISBN 0 580 16104 8 National foreword This Subsection of BS6200 has been prepared under the direction of the Iron and Steel Standards Committee. It is identical with ISO4829-1:1986 “Steel and cast ironDetermination of total silicon contentReduced
5、molybdosilicate spectrophotometric methodPart1: Silicon contents between0,05and1,0%”, published by the International Organization for Standardization (ISO), and supersedes method4 for the determination of silicon in BSI Handbook No.19. In1990 the European Committee for Standardization (CEN) accepted
6、 ISO4829-1:1986 as European Standard EN24829-1:1990. Terminology and conventions. The text of the International 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 Standa
7、rds; attention is drawn especially to the following. The comma has been used as a decimal marker. In British 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
8、 as “British Standard”. Cross-reference. The Technical Committee has reviewed the provisions of ISO377, to which reference is made in clause6, and has decided that they are acceptable for use in conjunction with this standard. A related British Standard to ISO377 is BS1837 “Methods for the sampling
9、of iron, steel, permanent magnet alloys and ferro-alloys”. Appropriate procedures from ISO377 will 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 Standard does not purport to include all the n
10、ecessary 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. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theE
11、N title page, pages2 to10, 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 the inside front cover. Amendments issued since publication Amd. No. Date of issue Comments
12、 7077 February 1992 Indicated by a sideline in the marginBS6200-3.26.3:1987 BSI 10-1999 i Contents Page National foreword Inside front cover Brief history 2 Text of EN 24829-1 3 Publications referred to Inside back coverii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN24829 Part 1 March19
13、90 UDC 669.1:543.42:546.28 Descriptors: Steels, cast iron, chemical analysis, determination of content, silicon, spectrophotometric analysis, molybdosilicate English version Steel and cast iron Determination of total silicon content Reduced molybdosilicate spectrophotometric method Part1: silicon co
14、ntent between0,05 and1% (ISO4829-1:1986) Aciers et fontesDtermination de la teneur en silicum totalMthode spectrophotomtrique par molybdosilicate rduit Partie1: teneur en silicum entre0,05 et1% (ISO4829-1:1986) Stahl und GueisenBestimmung Gesamtsiliciumgehalts Spectrophotometrisches Verfahren mittel
15、s reduzierten Molybdatosilicats Teil1: Siliciumgehalt zwischen0,05 und1% (ISO4829-1:1986) This European Standard was approved by CEN on1989-11-27. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of
16、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 three official versions (English, French, German). A version
17、 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 organizations of Austria, Belgium, Denmark, Finland, France, Germany,
18、 Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels CEN1990 Copyrig
19、ht reserved to all CEN members Ref. No. EN24829-1:1990 EEN24829-1:1990 BSI 10-1999 2 Brief history On the proposal of the Technical Committee ECISS/TC20 “Methods of chemical analysis” the Coordinating Commission (COCOR) of the European Committee for Iron and Steel Standardization (ECISS) decided in
20、November1988 to submit the International Standard ISO4829-1:1986, Steel and cast iron Determination of total silicon contentReduced molybdosilicate spectrophotometric method Part1: Silicon contents between0,05 and1%. to the Formal Vote. This European Standard was adopted by CEN on1989-11-27. Accordi
21、ng to the Common CEN/CENELEC Rules, being part of the Internal Regulations of CEN, 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, Sw
22、itzerland and UnitedKingdom. Statement The text of the International Standard ISO4829-1, edition1,1986 was approved by CEN as a EuropeanStandard without any modification. Contents Page Brief history 2 1 Scope and field of application 3 2 Reference 3 3 Principle 3 4 Reagents 3 5 Apparatus 4 6 Samplin
23、g 4 7 Procedure 4 8 Expression of results 6 9 Test report 7 Annex A Additional information on the international co-operative tests 8 Annex B Graphical representation of precision data 9 Figure Relationship between silicon content and repeatability r or reproducibility R 9 Table 1 5 Table 2 7 Table 3
24、 8EN24829-1:1990 BSI 10-1999 3 1 Scope and field of application This International Standard specifies a spectrophotometric method using reduced molybdosilicate for the determination of total silicon in steel and cast iron. The method is applicable to silicon contents between0,05 and1,0% (m/m) in ste
25、el and cast iron soluble in one or the other of the alternative acid mixtures. 2 Reference ISO377, Wrought steelSelection and preparation of samples and test pieces. 3 Principle Dissolution of a test portion in an acid mixture appropriate to the alloy composition. Fusion of the acid-insoluble residu
26、e with sodium peroxide. Formation of the oxidized molybdosilicate (yellow) in weak acid solution. Selective reduction of the molybdosilicate complex to reduced blue complex with ascorbic acid, after increasing the sulfuric acid concentration and adding oxalic acid to prevent the interference of phos
27、phorus, arsenic and vanadium. Spectrophotometric measurement of the reduced blue complex at a wavelength of about810nm. 4 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. All solutions shal
28、l be freshly prepared and stored in polypropylene or polytetrafluoroethylene containers. 4.1 Pure iron, silicon content less than54g/g. 4.2 Sodium peroxide, particle size5004m. 4.3 Nitric acid Slowly add150ml of nitric acid, approximately1,40g/ml, to600ml of water. Cool, dilute to1000ml and mix. 4.4
29、 Sulfuric acid To600ml of water add cautiously, with stirring,250ml of sulfuric acid, approximately1,84g/ml. Cool, dilute to1000ml and mix. 4.5 Sulfuric acid To800ml of water add cautiously, with stirring,50ml of sulfuric acid, approximately1,84g/ml. Cool, dilute to1000ml and mix. 4.6 Hydrochloric a
30、cid/nitric acid mixture Add180ml of hydrochloric acid, about1,19g/ml, and65ml of nitric acid, about1,40g/ml, to500ml of water, cool, dilute to1000ml and mix. 4.7 Sulfuric acid/nitric acid mixture To500ml of water add cautiously, with stirring,35ml of sulfuric acid, about1,84g/ml, and45ml of nitric a
31、cid, about1,40g/ml. Cool, dilute to1000ml and mix. 4.8 Ascorbic acid, 20g/l solution. Prepare this solution immediately before use. 4.9 Oxalic acid solution. Dissolve5g of oxalic acid dihydrate (C 2 H 2 O 4 2H 2 O) in water, dilute to100ml and mix. 4.10 Hydrogen peroxide Dilute200ml of hydrogen pero
32、xide,300g/l, to1000ml and mix. 4.11 Potassium permanganate, 22,5g/l solution. Filter before use. 4.12 Sodium molybdate solution. Dissolve2,5g of sodium molybdate dihydrate (Na 2 MoO 4 2H 2 O) in50ml of water and filter through a medium-texture filter paper. Immediately before use, add15ml of the sul
33、furic acid(4.5), dilute to100ml and mix. 4.13 Silicon, standard solution. 4.13.1 Silicon, stock solution corresponding to1g of Si per litre. Weigh, to the nearest0,1mg,2,1393g of freshly calcined high-purity silica (99,9% SiO 2 ) (seenote1) and transfer to a platinum crucible. Mix thoroughly with16g
34、 of anhydrous sodium carbonate and fuse at1050 C for30min. Extract the fusion product with100ml of water in a polypropylene or polytetrafluoroethylene beaker (seenote2). Transfer the extract, which should contain no trace of residue, to a1000ml one-mark volumetric flask, dilute to the mark and mix.
35、Transfer immediately to a well-stoppered polytetrafluoroethylene bottle for storage. 1ml of this stock solution contains1mg of Si. 4.13.2 Silicon, standard solution corresponding to200mg of Si per litre. Transfer50ml of the silicon stock solution(4.13.1) to a250ml one-mark volumetric flask. Dilute t
36、o the mark and mix. Transfer immediately to a well-stoppered polytetrafluoroethylene bottle for storage. 1ml of this standard solution contains2004g of Si. NOTE 1The high-purity silica shall be calcined for1h at1100 C and cooled in a desiccator immediately before use. NOTE 2Extraction of the fusion
37、product may require prolonged digestion in water followed by gentle heating.EN24829-1:1990 4 BSI 10-1999 5 Apparatus Ordinary laboratory apparatus and 5.1 Beakers, of polypropylene or polytetrafluoroethylene, of250ml capacity. 5.2 Crucibles, of zirconium metal (seenote), of50ml capacity. NOTESintere
38、d alumina crucibles may be used as alternatives to zirconium metal crucibles. 5.3 Spectrophotometer The spectrophotometer shall be equipped to measure absorbance with a spectral band width of10nm or less at a wavelength of810nm. Wavelength measurement shall be accurate to2nm as measured by the absor
39、ption maximum of a didymium filter at803nm, or other suitable calibration method. The absorption measurement for the solution of maximum absorbance shall have a repeatability expressed as relative deviation of 0,3% or better. 6 Sampling Carry out sampling in accordance with ISO377 or appropriate nat
40、ional standards for cast iron. 7 Procedure 7.1 Test portion Weigh, to the nearest0,001g,0,50 0,01g (m) of test sample in the form of fine chips, turnings, millings or filings. 7.2 Blank test In parallel with the determination and following the same procedure, carry out a blank test using the same qu
41、antities of all the reagents but using0,50 0,01g of the pure iron(4.1) (seenote) instead of the test portion. NOTEPure iron dissolves very slowly in the sulfuric acid/nitric acid mixture (4.7). It may be dissolved in85ml of the sulfuric acid (4.5) followed by35ml of the nitric acid (4.3). 7.3 Determ
42、ination 7.3.1 Dissolution of the test portion Transfer the test portion(7.1) into a250ml polypropylene or polytetrafluoroethylene beaker(5.1), add120ml of the sulfuric acid/nitric acid mixture(4.7) and warm gently to dissolve the test portion (seenotes1 and2). When solvent action ceases, filter the
43、solution through a hardened close-texture filter paper of known low ash content and collect the filtrate in a500ml beaker. Rinse the beaker with20ml of hot water, remove adherent particles with a rubber-tipped rod, and filter the rinsings through the same filter paper. Wash the filter paper several
44、times with20ml quantities of hot water. Keep the filtrate for use in the procedure given in7.3.3 (seenote3). NOTE 1For test portions slow to dissolve, the test portion may be dissolved in85ml of the sulfuric acid (4.5) followed by35ml of the nitric acid (4.3). NOTE 2For test portions not soluble in
45、the sulfuric acid/nitric acid mixture (4.7), use instead85ml of the hydrochloric acid/nitric acid mixture (4.6). NOTE 3If acid-soluble silicon only is required, proceed directly to7.3.3, but the method for acid-soluble silicon is unsatisfactory as different values could be obtained for some metals d
46、epending on the time of dissolution. 7.3.2 Treatment of insoluble residue Transfer the paper and residue to a zirconium metal crucible(5.2) and ignite at low temperature until carbonaceous matter is removed, then ignite in a furnace at600 C. Cool and mix the residue with0,25g of the sodium peroxide(
47、4.2). Cover with an additional0,25g of the sodium peroxide(4.2) and heat in the furnace at600 C for10min. Cool, add15ml of water, cover the crucible with a lid and allow the reaction to subside. Add15ml of the sulfuric acid(4.5), stir to dissolve any precipitate and add to the filtrate from the proc
48、edure given in7.3.1. Rinse the crucible and lid with water and add to the filtrate. 7.3.3 Preparation of the test solution Dilute the solution from7.3.1 or7.3.2 to approximately300ml and cool. Add5ml of the potassium permanganate solution(4.11), followed, if necessary, by further dropwise additions
49、until a definite pink colour is obtained which persists for at least1min. Heat to boiling and boil gently for2min. If necessary, add the hydrogen peroxide(4.10) dropwise until the precipitated manganese dioxide is just dissolved and boil gently for5min. Cool, transfer to a1000ml one-mark volumetric flask, dilute to the mark and mix. 7.3.4 Development of the colour Pipette two20ml aliquots from each test solution(7.3.3) (seenote) and blank test solution(7.2) into separate50ml borosilicate one-mark volumetric flasks
