1、BRITISH STANDARD BS 6200-3.21.1: 1986 EN10178: 1989 EU178:1985 Incorporating Amendment No.1 Sampling and analysis of iron, steel and other ferrous metals Part3: Methods of analysis Section 3.21 Determination of niobium Subsection 3.21.1 Steel: spectrophotometric method EU title: Chemical analysis of
2、 ferrous materials Determination of niobium in steels Spectrophotometric method The European Standard EN10178:1989 has the status of a British Standard UDC 543.42.062:546.882:669.14BS6200-3.21.1:1986 This British Standard, having been prepared under the directionof the Iron and Steel Standards Commi
3、ttee, was published under the authority ofthe Board of BSI and comes intoeffect on 30September1986 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference ISM/18 Draft for comment82/71477DC ISBN 0 580 15336 3 National foreword This Subsection of BS6200 has b
4、een prepared under the direction of the Iron and Steel Standards Committee. It is identical with Euronorm178:1985 “Chemical analysis of ferrous materials. Determination of niobium in steels. Spectrophotometric method” published by the Commission of the European Communities. In 1989 the European Comm
5、ittee for Standardization (CEN) accepted EU178:1985 as European Standard EN10178:1989. Cross-reference. The Technical Committee has reviewed the provisions of Euronorm18, to which reference is made in clause6, and has decided that they are acceptable for use in conjunction with this standard. At pre
6、sent there is no corresponding British Standard for Euronorm18. Appropriate procedures from Euronorm18 will be incorporated in BS6200-2 “Methods of sampling and sample preparation”, which will be published in due course. A British Standard does not purport to include all the necessary provisions of
7、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, theEN title page, pages2 to
8、6, 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 7075 February 1992 Indi
9、cated by a sideline in the marginBS6200-3.21.1:1986 BSI 09-1999 i Contents Page National foreword Inside front cover Brief history 2 1 Scope and field of application 3 2 Reference 3 3 Principle 3 4 Reagents 3 5 Apparatus 3 6 Sampling 3 7 Procedure 3 8 Expression of results 5 9 Test report 5 Annex Pr
10、ecision data 6 Publication referred to Inside back coverii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN10178 January 1989 UDC 543.42.062:546.882:669.14 Descriptors: Iron and steel products, chemical analysis, determination of content, niobium, spectrophotometric analysis English version
11、 Chemical analysis of ferrous materials Determination of niobium in steels Spectrophotometric method Analyse chimique sidrurgiques Dosage du niobium dans les aciers Mthode spectrophotomtrique Chemische analyse von Eisenwerk-stoffen Bestimmung von Niob in Sthlen Photometrisches Verfahren This Europea
12、n Standard was approved by CEN on 1989-01-15. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concernin
13、g 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 in any other language made by translation under the responsibility of a CEN member into its own lang
14、uage 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, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerla
15、nd and UnitedKingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels CEN 1989 Copyright reserved to all CEN members Ref.No.EN10178:1989EEN10178:1989 BSI 09-1999 2 Brief history This Eur
16、opean Standard takes over the content of EURONORM178:1985 “Chemical analysis of ferrous materials Determination of niobium in steels Spectrophotometric method”, prepared by ECISS/TC20 “Methods of chemical analysis”, the Secretariat of which is allocated to the Dansk Standardiseringsrad (DS). It has
17、been submitted to the CEN Formal Vote following the decision of the Coordinating Commission (COCOR) of the European Committee for Iron and Steel Standardization on 1987-11-24/25. It has been adopted and ratified by CEN BT on1988-11-05. According to the Common CEN/CENELEC Rules, the following countri
18、es are bound to implement this EuropeanStandard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom. Note in clauses1 and9 EURONORM shall read EUROPEAN STANDARD.EN10178:1989 BSI
19、 09-1999 3 1 Scope and field of application This EURONORM specifies a method for the spectrophotometric determination of niobium in steels. The method is applicable to all types of steels with niobium contents up to1.3% (m/m), with a lower detection limit of0.002%(m/m). 2 Reference EURONORM18, Selec
20、tion and preparation of samples and test pieces for steel and iron and steel products. 3 Principle Dissolution of a test portion with hydrochloric acid followed by oxidation with hydrogen peroxide. Precipitation of niobium and tantalum with phenylarsonic acid using zirconium as a carrier. Formation
21、of a complex of niobium with4-(2-pyridylazo)-resorcinol (PAR) in a buffered sodium tartrate medium. Spectrophotometric measurement of the coloured compound at a wavelength of550nm. 4 Reagents During the analysis, use only reagents of recognized analytical quality and only distilled water or water of
22、 equivalent purity. 4.1 Iron, of high purity, free from niobium 4.2 Potassium hydrogen sulphate (KHSO 4 ) 4.3 Hydrochloric acid, 1.19g/ml approximately,(12mol/l approximately) 4.4 Hydrochloric acid, 1.19g/ml approximately, diluted1+4(V/V),(2.4mol/l approximately) 4.5 Hydrochloric acid, 1.19g/ml appr
23、oximately, diluted1+9(V/V),(1.2mol/l approximately) 4.6 Sulphuric acid, 1.84g/ml approximately, diluted1+1(V/V),(9mol/l approximately) 4.7 Sulphuric acid, 1.84g/ml approximately, diluted1+4(V/V),(3.6mol/l approximately) 4.8 Ethylenediaminetetra-acetic acid di-sodium salt, (EDTA Na 2 ),15g/l solution
24、 Store in a polyethylene bottle. 4.9 Hydrogen peroxide,30%w/v(100vol.) 4.10 Phenylarsonic acid,40g/l solution 4.11 Phenylarsonic acid,0.5g/l solution 4.12 4-(2-pyridylazo)-resorcinol mono-sodium salt, (PAR),0.6g/l solution NOTEThe di-sodium salt may also be used but the identical salt must be used f
25、or both calibration and tests. 4.13 Sodium acetate buffer,350g/l solution Dissolve350g of sodium acetate trihydrate in700ml of water, add5.5ml of glacial acetic acid, 1.05g/ml, dilute to1000ml and mix. Adjust the pH value to6.3 with small additions of acetic acid or sodium hydroxide solution(4.14) u
26、sing a pHmeter for measurement. 4.14 Sodium hydroxide,120g/l solution Store in a polyethylene bottle. 4.15 Tartaric acid,100g/l solution 4.16 Zirconium nitrate,3g/l solution in hydrochloric acid medium Dissolve0.3g of zirconium nitrate in50ml of hydrochloric acid solution(4.4). Filter through a fine
27、 filter paper, dilute to100ml with water and mix. 4.17 Niobium reference solution, corresponding to0.2mg of niobium per millilitre Weigh0.1431g of niobium pentoxide and transfer to a platinum dish. Fuse with3.5g of potassium hydrogen sulphate(4.2). Cool and dissolve in40ml of tartaric acid solution(
28、4.15). Add a further160ml of tartaric acid solution(4.15). Transfer to a500ml volumetric flask, dilute to the mark with water and mix. 5 Apparatus Ordinary laboratory equipment and a spectrophotometer suitable for measuring the absorbance of the solution at a wavelength of550nm, together with4 or1cm
29、 cells. 6 Sampling Sampling shall be carried out in accordance with EURONORM18. 7 Procedure 7.1 Test portion Weigh the mass (m) indicated to the nearest0.001g: m=1g5% 7.2 Blank test With each analytical run, carry out an analysis on a1g portion of pure iron(4.1) in parallel with the test portion ana
30、lysis, using identical reagents, conditions and dilutions throughout.EN10178:1989 4 BSI 09-1999 7.3 Determination 7.3.1 Preparation of the test solution Transfer the test portion(7.1) to a400ml squat beaker, add40ml of hydrochloric acid solution(4.3), cover the beaker with a clock glass and heat unt
31、il solvent action ceases. Cool slightly and add with caution5ml of hydrogen peroxide solution(4.9). Boil the solution for1min., dilute to approximately200ml with warm water and add5ml of zirconium nitrate solution(4.16). 7.3.2 Separation of the niobium Heat the solution to boiling and add25ml of a b
32、oiling solution of phenylarsonic acid(4.10). Boil for5min, add a small amount of filter paper pulp, mix well and allow to stand for10min. Filter through a pulp pad prepared from macerated filter paper and remove adhering particles from the beaker with a rubber-tipped glass rod. Wash the filter alter
33、nately with hot dilute hydrochloric acid solution(4.5) and cold phenylarsonic acid solution(4.11) until freed from iron salts. Finally wash several times with cold phenylarsonic acid solution(4.11). Transfer the filter and precipitate to a silica crucible. Dry, ignite at as low a temperature as poss
34、ible until all carbon-aceous matter is removed, and finally at800 C for at least15min. Cool in a desiccator, add a few drops of sulphuric acid solution(4.6) and evaporate to dryness very carefully. Heat to remove sulphur trioxide. 7.3.3 Preparation of the solution for spectrophotometry Add2g of pota
35、ssium hydrogen sulphate(4.2) and fuse carefully until a clear melt is obtained. Cool and dissolve the fusion products with50ml of a warm solution of tartaric acid(4.15) and transfer to a400ml beaker. Add50ml of water and mix. Add25ml of sodium hydroxide solution(4.14) and cool. By means of a pH mete
36、r adjust the pH of the solution to approximately6.0 with either sulphuric acid solution(4.7) or sodium hydroxide solution(4.14) as required. Cool to room temperature, transfer to a250ml volumetric flask, dilute to the mark with water and mix. 7.3.4 Development of the colour Take an aliquot volume of
37、 the test solution(7.3.3) according to the following table: Transfer the aliquot to a100ml volumetric flask. By means of a pipette add10ml of EDTA Na 2solution(4.8),10ml of PAR solution(4.12) and10ml of buffer solution(4.13), mixing well after each addition. Allow to stand for15min. at approximately
38、20 C, then dilute to the mark with water and mix. Allow to stand for a further30min. 7.3.5 Spectrophotometric measurement Carry out the spectrophotometric measurement at a wavelength of550nm after having set the spectrophotometer to zero absorbance in relation to water. Use4cm cells for niobium cont
39、ents up to0.06% and1cm cells for contents greater than0.06%. Convert the readings for the test portion solution and for the blank test solution to milligrams of niobium by reference to the calibration graph(7.4). 7.4 Establishment of the calibration graph 7.4.1 Preparation of the calibration solutio
40、ns Weigh1.0g portions of pure iron(4.1) into a series of400ml beakers. Add from a burette, volumes of niobium reference solution(4.17) as shown in the table below: Continue as described in clauses7.3.1 to7.3.4 but in all cases taking a25ml aliquot in7.3.4. 7.4.2 Spectrophotometric measurements Carry
41、 out spectrophotometric measurements according to the method described in paragraph1 ofclause7.3.5, after having adjusted the spectrophotometer to zero absorbance in relation to water. 7.4.3 Plotting the calibration graph From each of the absorbance readings, subtract the reading obtained on the tes
42、t portion with no added niobium. Prepare a calibration graph by plotting the net absorbance readings against milligrams of niobium. Niobium % (m/m) Volume of aliquot (ml) Less than0.26 25.0 0.260.65 10.0 0.651.30 5.0 Niobium solution ml Niobium added mg Cell size 0 1.0 2.0 3.0 5.0 7.0 9.0 11.0 13.0
43、0 0.2 0.4 0.6 1.0 1.4 1.8 2.2 2.6 1 and4cm 4cm 4cm 1 and4cm 1cm 1cm 1cm 1cm 1cmEN10178:1989 BSI 09-1999 5 NOTEFor test samples containing more than0.26% of niobium and for which10ml or5ml aliquots are used the relationship with the calibration curve based on25ml aliquots is as follows: 8 Expression
44、of results The percentage by mass of niobium (Nb) is given by the expression 9 Test report The test report shall contain the following particulars: a) the method of analysis used by reference to this EURONORM; b) the results obtained, as well as the form in which they are expressed; c) any particula
45、r details which may have been noted during the determination; d) any operations not specified in this EURONORM or any optional operations which could have had an influence on the result; e) all indications necessary for the identification of the sample; f) the laboratory and the date of analysis. Eq
46、uivalent% Nb on1g sample Cell size 25ml aliquot 10ml aliquot 5ml aliquot 0 0.02 0.04 0.06 0.10 0.14 0.18 0.22 0.26 0 0.25 0.35 0.45 0.55 0.65 0 0.70 0.90 1.10 0.30 1 and 4 cm 4cm 4cm 1and4cm 1cm 1cm 1cm 1cm 1cm where: m is the mass, in grams, of the test portion; m 1 is the mass, in milligrams, of n
47、iobium found in the aliquot of the test portion solution; m 0 is the mass in milligrams of niobium found in the blank test solution; V is the aliquot volume, in millilitres, taken from the test portion solution. Nb % m/m () m 1 m 0 m 1 000 - = 250 V -100 m 1 m 0 m - 25 V - = EN10178:1989 6 BSI 09-19
48、99 Annex Precision data Planned trials of this method were carried out by10 analysts from different laboratories;5determinations were carried out by each analyst on each4samples;5determinations were made by7 of the analysts on a fifth sample.* From the results obtained the95%(2s) confidence limits h
49、ave been calculated in accordance with ISO5725, and are tabulated as follows: Repeatability The difference between two single results found on identical material by one analyst using the same apparatus within a short time interval will exceed the repeatability, r, not more than once in20cases in the normal and correct operation of the method. Reproducibility The difference between two single and independent results found by two operators worki
