1、BS EN ISO4945:2009ICS 77.080.20NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDSteel Determinationof nitrogen content Spectrophotometricmethod (ISO 4945:1977)This British Standard was published under the authority of the Standards Policy and Strategy Committee o
2、n 30 April2010 BSI 2010ISBN 978 0 580 68220 9Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 4945:2009National forewordThis British Standard is the UK implementation of EN ISO 4945:2009.It is identical to ISO 4945:1977. It supersedes BS 6200-3.22.2:1985 which is withdrawn.The UK
3、 participation in its preparation was entrusted to TechnicalCommittee ISE/102, Methods of Chemical Analysis for Iron and Steel.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof
4、a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunityfrom legal obligations.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 4945 October 2009 ICS 77.080.20 English Version Steel - Determination of nitrogen content - Spectrop
5、hotometric method (ISO 4945:1977) Acier - Dosage de lazote - Mthode spectrophotomtrique (ISO 4945:1977) Stahl - Bestimmung des Stickstoffgehalts - Spektralphotometrisches Verfahren (ISO 4945:1977) This European Standard was approved by CEN on 5 October 2009. CEN members are bound to comply with the
6、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 concerning such national standards may be obtained on application to the CEN Management Centre o
7、r 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 language and notified to the CEN Management Centre has the same status as the official ve
8、rsions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
9、 Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN nation
10、al Members. Ref. No. EN ISO 4945:2009: EEN ISO 4945:2009 (E) 2 Foreword The text of ISO 4945:1977 has been prepared by Technical Committee ISO/TC 17 “Steel” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 4945:2009 by Technical Committee ECISS/TC 20 “Met
11、hods of chemical analysis of ferrous products” the secretariat of which is held by SIS. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2010, and conflicting national standards shall be with
12、drawn at the latest by April 2010. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations,
13、the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands,
14、Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 4945:1977 has been approved by CEN as a EN ISO 4945:2009 without any modification. BS EN ISO 4945:2009BS EN ISO 4945:2009INTERNATIONAL STANDARD ISO 4945-1977 (
15、E) Steel - Determination of nitrogen content - Spectrophotometric method 1 SCOPE This International Standard specifies a spectrophotometric method for the determination of the nitrogen content of non-alloy and low-alloy steels. This method allows the determination only of the nitrogen content which
16、tan be converted to an ammonium salt. 2 FIELD OF APPLICATION The method is applicable to non-alloy and low-alloy steels containing between 0,002 % and 0,050 % (mlm) of nitrogen and less than 0,6 % (mlm) of Silicon. 3 REFERENCE ISOIR 377, Selection and preparation of samples and test pieces for wroug
17、h t steei. 4 PRINCIPLE Dissolution of a test Portion in dilute sulphuric acid. After concentration, progressive increasing of the tem- perature to above 300 “ C. Separation of ammonia from the ammonium salt formed, by displacement and distillation in a boiling sodium hydroxide medium and collecting
18、in an acid medium. At ambient temperature, formation of a blue-coloured complex between the ammonium ions and Phenol in the presence of sodium hypochlorite and sodium pentacyano- nitrosyIferrate( II) (sodium nitroprusside). Spectro- photometric measurement of the complex at a wavelength of about 640
19、 nm. 5 REAGENTS During the analysis, use only reagents of recognized analytical grade. 5.1 Distilled or de-ionized water, free from nitrogen compounds, purified by a second passage through ion- exchange resins. 5.2 Potassium sulphate, anhydrous (K,SO,). 5.3 Sulphuric acid, p approximately 1,84 g/ml,
20、 about 96 % (m/m) Solution, free from nitrogen compounds. 5.4 Sulphuric acid, p approximately 1,21 g/ml, about 29 % (mlm) solution. Add in small portions, whilst cooling, 200 ml of sulphuric acid (5.3) to about 700 ml of water (5.1), make up the volume to 1 000 ml with water (5.1) and mix. 5.5 Sodiu
21、m hydroxide, approximately 12 N Solution. Dissolve, with caution, 480 g of sodium hydroxide pellets in 700 ml of water (5.1) contained in a poly- tetrafluoroethylene beaker. Heat the Solution to boiling and boil for 10 min. Cool, make up the volume to 1 000 ml with water (5.1) and mix. Store in a su
22、itable plastics Container. 5.6 Sulphuric acid, approximately 1 N Solution. Add 30 ml of sulphuric acid (5.3) to about 700 ml of water (5.1); after cooling make up the volume to 1 000 ml with water (5.1) and mix. 5.7 Sulphuric acid, approximately 0,04 N Solution. Dilute 40 ml of sulphuric acid Soluti
23、on (5.6) to 1 000 ml with water (5.1) and mix. 5.8 Sodium hydroxide, approximately 0,2 N Solution. Dilute 30 ml of a 250 g/l Solution of sodium hydroxide with water (5.1), make up the volume to 1 000 ml with water (5.1) and mix. 5.9 Sodium phenate Solution. Add, whilst agitating and cooling, 5 g of
24、Phenol to a mixture of 10 ml of a 250 g/l Solution of sodium hydroxide and 80 ml of water (5.1). Make up the volume to 100 ml with water (5.1) and mix. Prepare this Solution at the time of use. 5.10 Disodium hydrogen Phosphate, 0,l M Solution. Dissolve 36 g of disodium hydrogen Phosphate dodeca- hyd
25、rate (Na,HP0,.12H,O) in water (5.1), make up the volume to 1 000 ml with water (5.1) and mix. 5.11 Disodium pentacyanonitrosylferrate( I I ), 0,25 g/l Solution. Dissolve IO g of disodium pentacyanonitrosylferrate( II) BS EN ISO 4945:2009BS EN ISO 4945:2009ISO 4945-1977 (E) dihydrate (sodium nitropru
26、sside) Na, Fe (CN), N0.2H,O in water (5.1), make up the volume to 1 000 ml with watet- (5.1) and mix. 8 PROCEDURE NOTE - Carry out operations in a from all work on nitrogenous products. weil-ventilated room away At the moment of use, dilute 25 ml of this Solution to 1 000 ml with water (5.1). 8.1 Te
27、st Portion Weigh, to the nearest 0,001 g, masses of 1 g and 2 g respect- ively of the test Sample, to be treated concurrently. 5.12 Sodium hypochlorite, approximately 0,l N Solution (approximately 0,3 % (mlm) of active chlorine). Store this Solution at a temperature less than 10 “ C. 8.2 Blank test
28、The procedure specified in 8.3 and 8.4 eliminates the inci- derice of the value of the blank test when the same reagents are used with the two test portions indicated in 8.1. 5.13 Nitrogen, Standard Solution corresponding to 0,100 0 g of nitrogen (N) per litre. Weigh, to the nearest 0,l mg, 0,471 6
29、g of dry ammonium sulphate, dissolve in water (5.1) and transfer the Solution quantitatively to a 1 000 ml one-mark volumetric flask. Dilute to the mark and mix. 8.3 Determination 8.3.1 Prepara tion c3 f the test Solution 1 ml of this Standard Solution contains 100 pg of nitrogen (N). In a 150 ml Kj
30、eldahl flask covered with a watch-glass, dissolve the test Portion (8.1) with 30 ml of sulphuric acid Solution (5.4). Allow to digest, taking care that the temperature of the liquid does not exceed 90 C, until the release of hydrogen has definitely ceased. 5.14 Nitrogen, Standard Solution correspond
31、ing to 0,002 0 g of nitrogen (N) per litre. Transfer 20,O ml of the Standard nitrogen Solution (5.13) to a 1 000 ml one-mark volumetric flask, dilute to the mark with water (5.1) and mix. When the release of hydrogen has ceased, remove the watch-glass and heat until white sulphuric fumes begin to ap
32、pear. 1 ml of this Standard Solution contains 2 pg of nitrogen (N). Then add - 5 ml of sulphuric acid (5.3) and Prepare this Standard Solution at the time of use. - 1 g of potassium sulphate (5.2). 5.15 Methyl red, 0,l g/l Solution. Heat for 2 h at a temperature above 300 OC, in such a way that the
33、mixture remains liquid. Cool, add IO ml of water (5.1) and heat to dissolve the majority of the sulphates. Dissolve 0,l g of methyl red in water (5.1), make up the volume to 1 000 ml with water (5.1) and mix. 8.3.2 Distilla tion The distillation additional steam. may be carried out with or without 6
34、 APPARATUS Ordinary laboratory apparatus and NOTE - The fl asks used in d istillation are attacked sodium hydroxide Solution; Change them frequently. by the 6.1 Semi-micro apparatus for additional steam (see figure 1) or distillation without 8.3.2. STEA 1 DISTILLATION WITHOUT ADDITIONAL M 6.2 Appara
35、tus for distillation under a current of steam (see figure 2). Use the apparatus shown in figure 1 (6.1). To collect the distillate, transfer 5 ml of sulphuric acid Solution (5.6) to a 100 ml volumetric flask with a ground neck and having a mark at 85 ml. Introduce the tapered tube extension of the c
36、ondenser into the flask in such a manner that it is immersed in the sulphuric acid Solution (5.6). 6.3 Spectrophotometer. NOTE - All glassware shall be cl eaned Prior to use in hot sulphuric- Chrom ic acid prepared f rom pure ingredients and water (5. 1). Pass the test Solution (8.3.1) quantitativel
37、y into the distillation flask, rinsing with 60 ml of water (5.1), add 50 ml of sodium hydroxide Solution (5.5) and rinse the neck of the flask with 30 ml of water (5.1). The final volume of the Solution should be approximately 160 to 165 ml. Moisten the ground neck and connect the flask 7 SAMPLING S
38、ampling shall be carried out in accordance with ISO/R 377. For wrought steels not complying with lSO/R 377, the appropriate national Standard shall be used. 2 BS EN ISO 4945:2009BS EN ISO 4945:2009ISO 49454977 (E) to the condenser immediately after the addition of the sodium hydroxide Solution (5.5)
39、. Now begin the distillation. Distil about 80 ml in 25 min. When the distillation is ended, rinse the immersed tube with water (5.1), collecting the washings in the volumetric flask; make up to volume with water (5.1) and mix. Solutions S, for the 1 g test Portion and S, for the 2 g test Portion are
40、 obtained. Repeat the same Operation (8.3.2.1) for each Sample to be analysed, taking care, after each distillation, to rinse the flask with plenty of water, then distilled water and finally the water (5.1). NOTE - To regulate the boiling during the distillation in the apparatus shown in figure 1, i
41、t is as weil to add some pieces of porous ceramic. These pieces are previously treated as a test Sample and collected up after distillation. They are then washed with sulphuric acid Solution (5.6) until neutral, then with water (5.1) and finally dried. 8.3.2.2 DISTILLATION UNDER A CURRENT OF STEAM U
42、se the apparatus shown in figure 2 (6.2). To collect the distillate, transfer 5 ml of sulphuric acid (5.7) to a beaker of suitable capacity, introduce the tapered tube extension of the condenser into this beaker which has a mark at 85 ml, in such a manner that it is immersed in the 5 ml of sulphuric
43、 acid Solution (5.7). Pass the test Solution (8.3.1) quantitatively into the distillation flask with the aid of the funnel. Rinse the Kjeldahl flask with 60 ml of water (5.1), add through the funnel 50 ml of sodium hydroxide Solution (5.5) and rinse the funnel with 30 ml of water (5-l). The volume o
44、f the Solution should then be about 160 to 165 ml. The steam generator should be preheated to allow the distillation to commence immediately the sodium hydroxide is introduced. Distil about 80 ml in 25 min. When the distillation is ended, rinse the immersed tube with water (5.1), collecting the wash
45、ings in the beaker. Transfer the Solution quantitatively to a 100 ml one-mark volumetric flask, make up to volume with water (5.1) and mix. Solutions S, for the 1 g test Portion and S, for the 2 g test portion are obtained. Interrupt the heating of the steam generator and allow to cool; the liquid i
46、n the flask syphons into the empty flask. Repeat the same Operation for each Sample to be analysed. 8.3.3 Development of the cofour According to the presumed nitrogen content, take the following aliquots of solutions S, and S, : - IO,0 ml for nitrogen contents between 0,020 and 0,050 % (mlm) - 25,0
47、ml for nitrogen contents between 0,010 and 0,020 % (mlm) - 50,O ml for nitrogen contents between 0,002 and 0,010 % (mlm) and transfer them respectively into two 100 ml volumetric f lasks. Make up to 50 ml with water (5.1) those volumes less than 50 ml. Add 1 drop of methyl red Solution (5.15) and ne
48、utralize exactly with sodium hydroxide Solution (5.8). Add with a pipette and in the following Order : - 5,0 ml of sodium phenate Solution (5.9) - 5,0 ml of cCsodium hydrogen Phosphate solutil (5.10) - IO,0 ml of sodium pentacyanonitrosyIferrate( Solution (5.11) - 5,0 ml of sodium hypochlorite Solut
49、ion (5.12). on Make up the volume to 100 ml with water (5.1) and agitate the flasks in an identical manner by alternately turning them upside down (at least ten times). Allow the colou tempe ratu re. r to develop in the dark for 1 h at ambient NOTE - The aliquots indicated are such that in relation to the nitrogen contents, the quantity of nitrogen in the 100 ml flask used for the spectrophotometric measurement is always between 10 and 50 1-19 for SJ and 20 and 100 pg for S2 : thus, the differente is between 10 and 50 pg. 8.3.4 Spectropho tome tric measuremen t Homogeniz
