BS 6200-3 22 3-1986 Sampling and analysis of iron steel and other ferrous metals - Methods of analysis - Determination of nitrogen - Steel spectrophotometric method (for trace amou.pdf

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1、t I BSI BS*b2OO:*SUB SEC*3-22.3 O1 m lb24bb9 0278577 T m .- BO BS 6200 : Subsection 3.22.3 : 1986 EN 10179 : 1.989 EU 179-1985 UDC 543.42.062:546.17:669.14. 0 British Standards Institution. No part of this publication may be photocopied or otherwise reproduced without the prior permission in writing

2、 of BSI British Standard Sampling and analysis of iron, steel and other ferrous metals Part 3. Methods of analysis Section 3.22 Determination of nitrogen Subsection 3.22.3 Steel: spectrophotometric method (for trace amounts) EU title : Chemical analysis of ferrous materials. Determination of nitroge

3、n (trace amounts) in steels. Spectrophotometric met hod I Echantillonnage et analyse du fer, de lacier et dautres mtaux ferreux Partie 3. Mthodes danalyse Section 3.22 Dosage de lazote Sous-section 3.22.3 Acier: mthode spectrophotomtrique (dosage de lazote en traces) Probenahme und Analyse von Eisen

4、, Stahl und anderen Eisenmetallen Teil 3, Analysenverfahren Abschnitt 3.22 Stickstoffbestimmung Unterabschnitt 3.22.3 Stahl: Spektrophotometrie Contents National foreword Method 1. Scope and field of application 2. Reference 3. Principle 4. Reagents 5. Apparatus 6. Sampling 7. Procedure Page 1 2 2 2

5、 2 4 4 4 8. Expression of results 9. Test report Annex Precision data Figures 1. Cation exchange column 2. Example of aluminium alloy heating block 3. Steam distillation apparatus National foreword This Subsection of BS 6200 has been prepared under the direction of the Iron and Steel Standards Commi

6、ttee. Page 5 6 6 7 8 9 It is identical with Euronorm 179-1 985 Chemical analysis of ferrous materials. Determination of nitrogen (trace amounts) in steels. Spectrophotometric method published by the Commission of the European Communities and supersedes method 2 for the determination of nitrogen in B

7、SI Handbook No. 19. In 1989 the European Committee for Standardization; (CEN) accepted EU 179-1985 ias European Standard EN 10179 : 1989. Cross-reference. The Technical Committee has reviewed the provisions of Euronorm 18, to which reference is made in clause 6, and has decided that they are accepta

8、ble for use in conjunction with this standard. At present there is no corresponding British Standard for Euronorm 18. Appropriate procedures from Euronorm 18 will be incorporated in BS 6200 : Part 2 Methods of sampling and sample preparation, which will be published in due course. Compliance with a

9、British Standard does not of itself confer immunity from legal obligations. 5 I BSI BS*b200:*SUB SEC*3-22*3 OI Lb24bb9 0278578 I % EUROPEAN STANDARD NORME EUROPEENNE EUROPISCHE NORM EN 10179 January 1989 UDC 543.42.062:546.17668.14 Descriptors: iron and steel products, chemical analysis, determinati

10、on of content, nitrogen, spectrophotometric analysis English version Chemical analysis of ferrous materials - Determination of nitrogen (trace amounts) in steel - Spectrophotometric method Analyse chimique des matriaux sidrurgiques - Dosage de lazote ( ltat de traces) dans les aciers -Mthode spectro

11、photomtrique Chemische Analyse von Eisen- und StahlwerkStoffen - Bestimmung von stickstoff (Spuren-Gehalte) in Staw. - Photometzisches Verfahren This European Standard was approved by CEN on 1989-01-15. CEN members are bound to comply with the CENICENELEC internal Regulations which stipdate the cond

12、itions for giving this European Standard the status of a national standard thout 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 o

13、fficial versions (Engiish, 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 organizations of

14、 Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom CEN a European Committee for Standardization comit Europen de Normalisation Europisches Komitee fr Normung Centrai Secretari

15、at: rue de Stassart 36, B-1060 Brussels O CEN 1989 Copyright reserved to ali CEN members Ref, No. EN 10179 : 1989 E Page 2 EN 10179 : 1989 Brief history This European Standard takes over the content of EURONORM 179-85 Chemical analysis of ferrous materials - Determination of nitrogen (trace amounts)

16、 in steels - Spectrophotometric method, prepared by ECISS/TC 20 Methods of chemical analysis, the Secretariat of which is allocated to the Dansk Standardiseringsrad (DS). It has been submitted to the CEN Formal Vote following the decision of the Coordinating Commission (COCOR) of the European Commit

17、tee for Iron and Steel Standardization on 1987-11-24/25. It has been adopted and ratified by CEN BT on According to the Common CENCENELEC Rules, the following countries are bound to implement this European Standard Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,

18、 Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Note in clauses 1 and 9 EURONORM shall read EUROPEAN STANDARD. 1988-11-05. - =-_ ;-$ - - . y- .- c - BSI BS*b2OO:*SUB SEC*3.22.3 O1 m 3624669 O278580 T = - BS 6200 : Subsection 3.22.3 : 1986 I. SCOPE AND FIELD

19、 OF APPLICATION This EURONORM specifies a method for the spectrophoto metric determination of nitrogen in steels. The method is primarily intended for the determination of total nitrogen in very low nitrogen non alloy steels It may be used. however. for any low nitrogen ferrous alloy that is soluble

20、 in hydrochloric acid provided that the acid resistant form of silicon nitride is not present This highly resistant nitride has been found only in samples of silicon steels manu factured without aluminium addition and then only in sheet material. The method is applicable to nitrogen contents from 0.

21、0005 to 0.005% (m/m). NOTE - The method has also been successfully applied to a pure iron with a nitrogen content of 0.003816 (m/m) - see Annex. 2. REFERENCE EURONORM 18 - Selection and preparation of samples and test pieces for steel and iron and steel products. 3. PRINCIPLE Dissolution of the lest

22、 portion with hydrochloric acid and separation of the acid-insoluble residue by means of a centri fuge Decomposition of the acid insoluble residue by intense fuming with sulphuric acid and addition of the extract to the solution of the test portion containing the acid soluble nitrogen. Recovery of t

23、he total nitrogen as ammonia by steam distilla- tion over sodium hydroxide. Spectrophotometric measurement of the coloured complex produced by the indophenol blue reaction. 4. REAGENTS During the analysis use only reagents of recognized analytical reagent quality and which are known to give a very l

24、ow nitrogen blank. The same batch of each reagent shall be used for every test and blank determination in a given series of tests. through the cation exchange column (5,l). It is essential that the resin column shall be acid washed before use to ensure its conversion to the hydrogen form (H+). This

25、is most conveni- ently done by passing 2 litres of hydrochloric acid p 1.19 g/ml approximately, diluted 1 + 9 (V/V), through the column, then washing with water until freed from acid. All references to water relate to ammonia-free water. Am- monia-free water shall be prepared by passing distilled wa

26、ter BSI BS*bEOO:*SUB SEC*3*22.3 O1 1624bb 0278583 3 I: BS 6200 : Subsection 3.22-3 : 1986 4.1 Iron of high purity or steel of very low nitrogen content NOTE - High purity iron powder or very low nitrogen mild steel ( O.OOi?/o nitrogen) may be used for this purpose. It should be washed in the same wa

27、y as the sample. 4.2 Hydrochloric acid, p 1.19 g/ml approximately (i 2 mol/l approximately) 4.3 Sulphurk acid, p 1.84 g/ml approximately, (1 8 mol/ 1 approximately) Sulphuric acid supplies shall be tested individually and se- lected for a low content of combined nitrogen in any form (less than 0.5 p

28、pm). Nitrogen as ammonia will usually be the major source of contamination and this may be tested by the normal methods, but nitrates may also be present and may be detected by the following method. Add 6 ml of the sulphuric acid to 2 ml of water and cool to 60 “C. Add one drop of hydrochloric acid

29、(4.2) and one drop of diphenylamine reagent (4.8). No blue colour should de- velop. Less than O. l ppm can be detected by this test. 4.4 Sulphuric acid, p 1.84 g/ml approximately, diluted I + 4 (VD) (3.6 mou1 approximately) 4.5 Sodium hydroxide, 400 g/l solution Dissolve 400 g of sodium hydroxide in

30、 water, dilute to 1 O00 ml and mix. This solution should be prepared in a polyethyl- ene beaker (water-cooled if necessary) and stored in a poly- ethylene bottle. 4.6 Barium chloride, 100 g/l solution Dissolve 100 g of barium chloride (BaCI2.2H2O) in water, dilute to 1 O00 ml and mix. 4.7 Chromic-su

31、lphuric acid* Dissolve 2 g of chromium trioxide in 50 ml of water, and add slowly 100 ml of sulphuric acid (4.3) with constant stirring. 4.8 Diphenylamine reagent* To 25 ml of water, whilst stirring, cautiously add 75 ml of sulphuric acid (4.3) then add 0.1 g diphenylamine, stir until dissolved and

32、cool. 4.9 Phenol, 50dl solution Dissolve 50 g of phenol in water, transfer to a 1 O00 ml volumetric flask, dilute to the mark with water and mix. (Store out of direct sunlight in an amber coloured bottle). 4.10 Sodium hydroxide-sodium hypochlorite so- 4.10. I Determination of available chlorine in c

33、ommercial lution sodium hypochlorite solution By means of a burette, transfer 10 ml of the sodium hypo- chlorite solution to a 250 ml volumetric flask, dilute to the mark with water and mix. Transfer, by means of a safety pipette, IO ml of this solution to a 100 ml conical beaker, add 2 g of potassi

34、um iodide and 10 ml of glacial acetic acid, p 1.048-1.050 g/ml approxi- mately. Titrate the Liberated iodine using sodium thiosulphate (4.12) until the colour is almost discharged. Add 2 ml of starch solution (4.13), and continue the titration until the blue colour is discharged. Available chlorine

35、per cent (w/v) = 0.886 . V where V is the volume in millilitres of sodium thiosulphate (4.12) used in the titration. 4.10.2 Calculation The volume of sodium hypochlorite solution required for the preparation of 1 I of sodium hydroxide-sodium hypochlorite solution (4.10) is 2.1 . 100. 70.91 225.7 ml

36、0.886. V. 74.44 - . V - This volume is equivalent to 2. I g of available chlorine. 4.10.3 Preparation of solution 4.10 Dissolve 25 g of sodium hydroxide in about 400 ml of water. Add the calculated volume of sodium hypochlorite solution (4.10.2) from a burette, dilute to I O00 ml and mix. (Store out

37、 of direct sunlight in an amber bottle). 4.1 1 Sodium pentacyanonitrosyiferrate (sodium nitroprusside) (Na, Fe(CN),NO 2H20) Dissolve O. 1 g of sodium pentacyanonitrosylferrate h water, dilute to 100 ml and mix. Prepare freshly each day, store in an amber coloured bottle but do not use until at least

38、 60min. after preparation. 4.12 Sodium thiosulphate, 0.05 mol solution* Dissolve 24.82 1 g of sodium thiosulphate (Na,Sz0,.5H20) in water containing 0.1 g of sodium carbonate. Transfer to a 1 O00 ml volumetric flask, dilute to the mark with water and mix. 4.13 Starch, 5 g/l solution* Make a suspensi

39、on of 0.5 g of starch in 10 ml of water. Add to 90 ml of boiling water. Cool, dilute to LOO ml and mix. 4.14 Ammonium chloride reference solution cor- responding to 1 ,ug of nitrogen per millilitre Dissolve 0.382 g of ammonium chloride (previously dried to constant weight at 105 OC) in water, transf

40、er to a 1 000 ml 3 - BSI BS*b2OO:*SUB SEC*3.22.3 O1 I 1b24bb 0278582 3 BS 6200 : Subsection 3.22.3 : 1986 volumetric flask, dilute to the mark and mix. Transfer IO ml of this solution to a 1 O00 ml volumetric flask, dilute to the mark and mix. * Reagents marked with an aslerisk are not used in the d

41、elermi- nalion itseif bui only Sor auxiliar79 purposes, e.g. ihe prepara- lion of other reagent solutions. 5. APPARATUS Ordinary laboratory equipment and 5.3 Steam distillation apparatus 5.1 Cation exchange column The distillation unit illustrated in Fig. 3 has been found suitable. A column packed w

42、ith a sulphonated polystyrene cation exchange resin (Fig. I). 5.4 Centrifuge 5.2 Aluminium alloy heating block An aluminium alloy block containing a number of sockets for the purpose of supporting 50 ml centrifuge tubes (Fig. 2) and heated by contact with the surface of a hotplate. NOTE - It is esse

43、ntial that the hot plate is capable of heating the test solutions to a temperature of at least 320OC. This should be checked by inserting a thermometer in sulphuric acid under test conditions. An electrically driven centrifuge capable of taking tubes of 50 ml capacity and attaining a steady speed of

44、 3 500 revolu- tions per minute. 5.5 A spectrophotometer suitable for measuring the absorbance of the solution at a wavelength of 635 nm together with 1 cm cells 6. SAMPLING Sampling shall be carried out in accordance with EURONORM 18. 7. PROCEDURE NOTE - It is essential that nitrogen determinations

45、 shall be carried out in a laboratory reserved for the purpose and it is particularly important that ammonium salts and ammonia fumes should be excluded. In addition, the glassware should be reserved for this work only and should be cleaned with the chromic-sulphuric acid solution (4.7), and thoroug

46、hly washed with ammonia-free water before use. 7.1 Test portion NOTE - Sample millin or drillings should be washed in ether to remove any contamination by oil. If the drillings or millings have been stored in the chemical laboratory they should be washed in hot water and dried immediately before det

47、ermining the nitrogen content. Weigh the mass (m) indicated below to the nearest 0.001 g ; m = 1.0 g 2 5% and also to the same accuracy 0.25 g of high purity iron (4. I). 7.2 Blank test With each analytical run, carry out an analysis on a 0.25 g portion of high purity iron (4. I) in parallel with th

48、e test portion analysis, using identical reagents and conditions throughout. 7.3 Preparation of the steam distillation apparatus Ammonia-free water shall be used exclusively in the steam generating flask A (Fig. 3). Any water left over from a previous day should be rejected and the flask rinsed befo

49、re refilling. Prepare the apparatus (Fig. 3) for use as follows: Fill the steam generator A with water, replace stopper G, open the screw clip K, and raise the funnel plug D. Heat the steam generator and boil the water vigorously, allowing the steam to escape for 30 min. via funnel C and the drain tube from steam trap B. Close the screw clip K, transfer 5 ml of sodium hydroxide solution (4.5) to the distillation vessel E via funnel C and lower the funnel plug D. Collect and discard about 50 ml of distillate and rinse the condenser