1、June 2007DEUTSCHE NORM English price group 11No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 77.040.30; 77.080.01!,y6=
2、“9861926www.din.deDDIN EN ISO 10720Steel and iron Determination of nitrogen content Thermal conductimetric method after fusion in a current of inert gas(ISO 10720:1997)English version of DIN EN ISO 10720:2007-06Eisen und Stahl Bestimmung des Stickstoffgehaltes Messung der Wrmeleitfhigkeit nach Aufsc
3、hmelzen in strmendem Inertgas(ISO 10720:1997)Englische Fassung DIN EN ISO 10720:2007-06www.beuth.deDocument comprises 15 pages 09.07DIN EN ISO 10720:2007-06 2 National foreword This standard has been published in accordance with a decision taken by ECISS/TC 20 “Methods of chemical analysis of ferrou
4、s products” (Secretariat: SIS, Sweden) to adopt, without alteration, International Standard ISO 10720 as a European Standard. The responsible German body involved in its preparation was the Normenausschuss Eisen und Stahl (Steel and Iron Standards Committee), Technical Committee 30 Analyseverfahren.
5、 This standard specifies a thermal conductimetric method after fusion under inert gas for the determination of nitrogen in steel and iron. The method is applicable to nitrogen contents between 0,000 8 % (m/m) and 0,5 % (m/m). EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 10720 March 2007
6、ICS 77.080.01 English Version Steel and iron - Determination of nitrogen content - Thermal conductimetric method after fusion in a current of inert gas (ISO 10720:1997) Aciers et fontes - Dosage de lazote - Mthode par conductibilit thermique aprs fusion dans un courant de gaz inerte (ISO 10720:1997)
7、 Eisen und Stahl - Bestimmung des Stickstoffgehaltes - Messung der Wrmeleitfhigkeit nach Aufschmelzen in strmendem Inertgas (ISO 10720:1997) This European Standard was approved by CEN on 24 February 2007. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the c
8、onditions 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 or to any CEN member. This European Standard exists in
9、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 versions. CEN members are the national standards bodies
10、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, Spain, Sweden, Switzerland and United Kingdom. EUROPEA
11、N COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 10720:2007: EForeword The
12、 text of ISO 10720:1997 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 10720:2007 by Technical Committee ECISS/TC 20 “Methods of chemical analysis of ferrous products” the secretariat of which i
13、s 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 September 2007, and conflicting national standards shall be withdrawn at the latest by September 2007. According to the CEN/CENELEC I
14、nternal Regulations, 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,
15、 Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Endorsement notice The text of the International Standard ISO 10720:1997 has been approved by CEN as EN ISO 10720:2007 without any modification. 2 EN ISO 10720:2007 (E):1 Scope
16、This International Standard specifies a thermal conductimetric method after fusion under inert gas for the determination of nitrogen in steel and iron. The method is applicable to nitrogen contents between 0,000 8 % (m/m) and 0,5% (m/m). 2 Normative references The following standards contain provisi
17、ons which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the poss
18、ibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 385-l :I 984, Laboratory glassware - Burettes - Part 1: General requirements. IS0 648:1977, Laboratory glassware - One-mark pipette
19、s. IS0 1042: -I), Laboratory glassware - One-mark volumetric flasks. IS0 3696:1987, Water for analytical laboratory use - Specification and test methods. IS0 5725-l :I 994, Accuracy (trueness and precision) of measurement methods and results - Part I: General principles and definitions. IS0 5725-2:1
20、994, Accuracy (trueness and precision) of measurement methods and results - Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method. IS0 5725-3:1994, Accuracy (trueness and precision) of measurement methods and results - Part 3: Intermediate m
21、easures of the precision of a standard measurement method. IS0 14284 :I 996, Steel and iron - Sampling and preparation of samples for the determination of chemical composition. 3 Principle Fusion of a test portion in a single-use graphite crucible under helium gas at a high temperature (e. g. 2 200
22、“C) Extraction of the nitrogen in the form of molecular nitrogen in the stream of helium. Separation from the other gaseous extracts and measurement by thermal conductimetric method. 4 Reagents and materials During the analysis, unless otherwise stated, use only reagents of recognized analytical gra
23、de and only grade 2 water as specified in IS0 3696. 1) To be published. (Revision of IS0 10427 983) EN ISO 10720:2007 (E)34.1 Water, prepare just before use. 4.2 Helium, high purity, total impurity content 0,000 5 % (m/m). An oxidation reagent or catalyst copper oxide or platinum tube heated to a te
24、mperature above 450 “C shall be used prior to a purifying unit, when the presence of organic contaminants is suspected in the helium. 4.3 Pure iron, of known low nitrogen contents less than 0,001 % (m/m). 4.4 Copper (II) oxide, on granulated support. 4.5 Anhydrous magnesium perchlorate, Mg(CIO,), pa
25、rticle size from I,2 mm to 2,O mm, or anhydrous calcium sulfate, particle size from 0,60 mm to 0,85 mm. 4.6 Sodium hydroxide, on granulated support. Particle size from 0,7 mm to I,2 mm. 4.7 Appropriate solvent, suitable for washing greasy or dirty test samples, e.g. acetone. 4.8 Potassium nitrate, s
26、tandard solution. After drying at between 100 “C and 105 OC for 2 h and allowing to cool in a desiccator, weigh, to the nearest 0,l mg, the masses of potassium nitrate purity 99,9 % (m/m) indicated in table 1. Dissolve the potassium nitrate in about 50 ml of water (4.1), transfer quantitatively to a
27、 100 ml one-mark volumetric flask, dilute to the mark with water (4.1) and mix. 1 ml of each standard solution contains the mass of nitrogen indicated in table 1. Table 1 - Standard solutions Name of the standard solution 4.8.1 4.8.2 4.8.3 4.8.4 4.8.5 4.8.6 4.8.7 4.8.8 4.8.9 4.8.10 Mass of potassium
28、 nitrate used cl 9,022 8 7,218 2 5,413 8 3,609 1 1,804 6 0,902 3 0,360 9 4.8.5 x l/10 ) 4.8.6 x l/IO 4.8.7 x l/IO Corresponding concentration of nitrogen mg/ml 12,5 IO,0 75 50 2,50 I,25 0,50 0,25 0,125 0,050 1) e.g. .transfer 10,O ml of the standard solution (4.8.5) into a 100 ml one-mark volumetric
29、 flask, dilute to the mark with water (4.1) and mix. 5 Apparatus During the analysis, unless otherwise stated, use only ordinary laboratory apparatus. 4 EN ISO 10720:2007 (E)All volumetric glassware shall be class A, in accordance with IS0 385-l) IS0 648 or IS0 1042 as appropriate. The apparatus req
30、uired for fusion of the test portion, separation and measurement of the nitrogen extracted may be obtained commercially from a number of manufacturers. Follow the manufacturers instructions for the operation of the instrument. Features of commercial instruments are given in annex A. 5.1 Graphite cru
31、cible, single-use. Use high purity crucibles suitable for use with the apparatus. 5.2 Micropipette, 100 ul and 200 1, limit of error shall be less than 1 1. 5.3 Nickel capsule. For example, about 6 mm in diameter; 8 mm in height; 0,2 g in mass and 0,23 ml in volume, or about 6 mm in diameter; 125 mm
32、 in height; 0,5 g in mass and 0,35 ml in volume. In any case, the nitrogen content shall be less than 0,000 2 % (mlm). 5.4 Crucible tongs, for handling the crucibles used. 5.5 Glass-wool filters. 6 Sampling Carry out sampling in accordance with IS0 14284 or appropriate national standards for steel a
33、nd iron. 7 Procedure WARNING - The risks involved when using an apparatus for fusing the test portion are mainly risks of burns. It is therefore essential to use crucible tongs (5.4) and appropriate containers for the used crucibles. 7.1 General instructions Keep the glass-wool filters (5.5) clean.
34、Using a certified reference material, verify the effectiveness of the installed reagents (4.4, 4.5 and 4.6) and change them if necessary. In certain instruments, it is necessary to clean the sample introduction pipe in the furnace after each analysis in order to eliminate carbon deposits. If the ele
35、ctricity supply has been switched off for a long time, allow time for the instrument to stabilize as recommended by the manufacturer. After changing the filters (5.5) and/or reagents (4.4, 4.5 and 4.6), or when the apparatus has been inoperative for a period, stabilize the instrument by carrying out
36、 trial analyses, the results of which are to be disregarded, then proceed with calibration as indicated in 7.5 before analysing the sample. If the instrument used provides a direct reading in percentage of nitrogen, adjust the instrument reading for each calibration range as follows. Read the conten
37、t of a certified reference material of high nitrogen content at various power settings. The required heating power for the determination of test samples is that at which the reading levels off. In order to determine a high alloy test sample a high alloy certified reference material shall be used to
38、know the required heating power. EN ISO 10720:2007 (E)57.2 Test portion Degrease the test sample by washing in a suitable solvent (4.7). Evaporate the last traces of the washing liquid by heating. Weigh, to the nearest 1 mg, approximately approximately 0,50 g for nitrogen contents cl ,0 g of the tes
39、t sample for nitrogen conte reater than 0,l % (m/m) (see note 1) . nts up to 0,l % ( m/m) NOTE 1 The mass of the test portion may be dependent on the type of instrument used. 7.3 Blank test Prior to the determination, carry out the following blank tests in duplicate. 7.3.1 Sample with nitrogen conte
40、nts up to 0,lO % (mlm) 7.3.1.1 Using the micropipette (5.2), transfer 200 1 of water (4.1) to a nickel capsule (5.3) and dry at 90 OC to 95 “C for 2 h. Treat the nickel capsule as specified in 7.4.1, and add the same quantity of the pure iron (4.3) in place of the test portion. 7.3.1.2 Obtain the re
41、ading of the blank tests and convert it to micrograms of nitrogen by means of the calibration graph (see 7.5). The blank value is obtained nitrogen in the blank tests. bY subtracting the of nitrogen in the pure iron used (4.3) from the mass of The mean blank value (m,) is calculated from the two bla
42、nk values (see note 2). NOTE 2 nitrogen. If It is essential that neither the m ean blank value nor the diffe rence between the two blank values exce these values are abnormally high, the source of contamination should be investigated and eliminated. IedlOpgof 7.3.2 Sample with nitrogen contents betw
43、een 0,lO % (ml and 0,50 % (m/m) Using the micropipette (5.2), transfer 200 1.11 of water (4.1) to a degassed graphite crucible (5.1) and dry at 90 OC to 95 OC for 2 h. Add the same quantity of the pure iron (4.3) instead of the test portion and proceed as specified in 7.3.1.2. 7.4 Determination 7.4.
44、1 Sample with nitrogen contents up to 0,lO % (m/m) 7.4.1.1 Place a graphite crucible (5.1) in the furnace (see annex A) and then degas by heating at greater than 22OOOC. 7.4.1.2 Flatten a nickel capsule (5.3) by pressing, insert it and add the test portion (see 7.2) to the degassed graphite crucible
45、. X4.1.3 Operate the furnace in accordance with the manufacturers instructions. At the end of the fusion and measuring cycle, remove and discard the crucible, and record the analyser reading. 7.4.2 Sample with nitrogen contents between 0,lO % (mlm) and 0,50 % (m/m) Place a graphite crucible (5.1) in
46、 the furnace (see annex A) and then degas by heating at greater than 2 200 OC. Add the test portion (see 7.2) to the degassed graphite crucible (5.1) and continue as specified in 7.4.1.3. 6 EN ISO 10720:2007 (E)7.5 Establishment of the calibration graph 7.51 Preparation of the calibration series 7.5
47、.1 .I Sample with nitrogen contents up to 0,lO % (m/m) Using the micropipette (5.2), transfer 200 1 of each of the potassium nitrate standard solutions (4.8) indicated in table 2, to the respective nickel capsule (5.3), and dry at 90 “C to 95 OC for 2 h. 7.5.1.2 Sample with nitrogen contents between
48、 0,lO % (m/m) and 0,50 % (m/m) Using the micropipette (5.2), transfer 200 1 of each of the potassium nitrate standard solutions (4.8) indicated in table 3, to the respective degassed graphite crucible(5.1), and dry at 90 “C to 95 OC for 2 h. 7.5.2 Measurements 7.5.2.1 Sample with nitrogen contents u
49、p to 0,lO % (m/m) Treat the nickel capsule (5.3) containing potassium nitrate as specified in 7.4.1. Add the same quantity of the pure iron (4.3) in place of the test portion. 7.5.2.2 Sample with nitrogen contents between 0,lO % (m/m) and 0,50 % (m/m) Add, to each dried graphite crucible, the same quantity of the pure iron (4.3) as that of the test portion used, and continue as specified in 7.4.1.3 7.5.3 Plotting the calibration graph Obtain the net reading by subtracting the reading of the zero member (see tables 2 and 3) from that of each m
