1、BRITISH STANDARD BS ISO 13899-2:2005 Steel Determination of Mo, Nb and W contents in alloyed steel Inductively coupled plasma atomic emission spectrometric method Part 2: Determination of Nb content ICS 77.080.20 BS ISO 13899-2:2005 This British Standard was published under the authority of the Stan
2、dards Policy and Strategy Committee on 25 August 2005 BSI 25 August 2005 ISBN 0 580 46377 X National foreword This British Standard reproduces verbatim ISO 13899-2:2005 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee ISE/18,
3、 Sampling and analysis of iron and steel, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in
4、 the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsib
5、le for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK in
6、terests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to iv, pages 1 to 13 and a back cover. The BSI copyright notice displayed in this docum
7、ent indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 13899-2:2005(E)INTERNATIONAL STANDARD ISO 13899-2 First edition 2005-06-15 Steel Determination of Mo, Nb and W contents in alloyed steel Inductively coupled plasma atomic
8、emission spectrometric method Part 2: Determination of Nb content Aciers Dosage du Mo, du Nb et du W dans les aciers allis Mthode par spectromtrie dmission atomique avec plasma induit par haute frquence Partie 2: Dosage du Nb BS ISO 13899-2:2005ii iii Contents Page Foreword iv 1 Scope . 1 2 Normativ
9、e references . 1 3 Principle. 1 4 Reagents 2 5 Apparatus 3 6 Sampling and samples. 4 7 Procedure 4 7.1 Preparation of test solution, T n . 4 7.2 Preparation for spectrometric measurements. 5 7.3 Pre-analysis of the test solution . 5 7.4 Preparation of calibration solutions for bracketing, K Lnand K
10、Hn . 6 7.5 Analysis of test solutions 6 8 Expression of results . 6 8.1 Method of calculation. 6 8.2 Precision 6 9 Test report . 7 Annex A (normative) Procedure for the determination of instrumental criteria 8 Annex B (informative) Suggested lines together with possible spectral interferences in the
11、 determination of Nb in steel by ICP-AES 10 Annex C (informative) Additional information on the international cooperative tests . 11 Annex D (informative) Graphical representation of precision data 13 BS ISO 13899-2:2005BS ISO 13899-2:2005 iv Foreword ISO (the International Organization for Standard
12、ization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to
13、be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Stand
14、ards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Inte
15、rnational Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 13899-
16、2 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 1, Methods of determination of chemical composition. ISO 13899 consists of the following parts, under the general title Steel Determination of Mo, Nb and W contents in alloyed steel Inductively coupled plasma atomic emission spe
17、ctrometric method: Part 1: Detemination of Mo content Part 2: Detemination of Nb content Part 3: Detemination of W content 1 Steel Determination of Mo, Nb and W contents in alloyed steel Inductively coupled plasma atomic emission spectrometric method Part 2: Determination of Nb content 1 Scope This
18、International Standard specifies a method for the determination of the niobium content in steel by means of inductively coupled plasma emission spectrometry. This method is applicable to niobium contents between 0,005 and 5 % (mass fraction). 2 Normative references The following referenced documents
19、 are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 648:1977, Laboratory glassware One mark pipettes ISO 1042:1983, Laboratory glas
20、sware One mark volumetric flasks ISO 3696:1987, Water for analytical laboratory use Specification and test methods ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results Part 1: General principles and definitions ISO 5725-2:1994, Accuracy (trueness and precision) of me
21、asurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method ISO 5725-3:1994, Accuracy (trueness and precision) of measurement methods and results Part 3: Intermediate measures of the precision of a standard measuremen
22、t method ISO 14284:1996, Steel and iron Sampling and preparation of samples for the determination of chemical composition 3 Principle The sample is dissolved in a hydrochloric, nitric and hydrofluoric acid mixture and fumed with a phosphoric and perchloric acid mixture. Hydrofluoric acid and an inte
23、rnal standard element (if used) are added and the solution is diluted to known volume. The solution is filtered and nebulized into an ICP and the intensity of the emitted light from each element is measured simultaneously with the light emitted from the internal standard element. BS ISO 13899-2:2005
24、2 The method uses a calibration based on close matrix matching of the calibration solutions to the sample and close bracketing of the niobium content around the approximate concentration of niobium in the sample to be analysed. This compensates for matrix interferences and provides high accuracy, ev
25、en in highly alloyed steels where spectral interferences can be severe. Nonetheless, all interferences shall be kept to a minimum and it is therefore essential that the spectrometer used meets the performance criteria specified in the method for the selected analytical lines. In order to accurately
26、matrix match, it is necessary to know the concentration of all elements in the sample (to the nearest percent). To this end, it may be necessary to carry out a preliminary analysis of the sample by some semi-quantitative method. 4 Reagents During the analysis, unless otherwise stated, use only reage
27、nts of recognised analytical grade and only grade 2 water, as specified in ISO 3696. 4.1 Hydrofluoric acid, HF, 40 % (m/m), approximately 1,14 g/ml. 4.2 Hydrochloric acid, HCl, approximately 1,19 g/ml. 4.3 Nitric acid, HNO 3 , approximately 40 g/ml. 4.4 Phosphoric acid, H 3 PO 4 , approximately 1,70
28、 g/ml, diluted 1 + 1. 4.5 Perchloric acid, HClO 4 , approximately 1,54 g/ml, diluted 1 + 1. 4.6 Fuming acid mixture, mix 100 ml of the phosphoric acid (4.4) and 300 ml of the perchloric acid (4.5). 4.7 Internal standard solution, 1 000 mg/l. Choose a suitable element to be added as internal standard
29、 and prepare a 1 000 mg/l solution. The internal standard chosen shall be pure, not be present in the sample, and not interfere with analytical wavelengths, nor should the internal standard element wavelength be interfered with by elements in the test solution. The internal standard shall be soluble
30、 in the acids used and it shall not cause precipitation. Moreover, the excitation conditions of the analytical line and the internal standard element line should match. 4.8 Niobium stock standard solution, 1 000 mg/l. Weigh, to the nearest 0,000 1 g, 0,5 g of high purity niobium min 99,95 % (mass fr
31、action) and dissolve in a mixture of 30 ml hydrofluoric acid (4.1) and 3 ml nitric acid (4.3). Cool and transfer the solution quantitatively to a calibrated 500 ml one-mark plastic volumetric flask. Dilute to the mark with water and mix. 1 ml of this solution contains 1 mg of Nb. NOTE It is not perm
32、itted to use pre-prepared niobium standard solutions supplied by second parties. 4.9 Niobium standard solution, 100 mg/l. Transfer, with a calibrated pipette, 25 ml of the niobium stock standard solution (4.8) into a calibrated 250 ml one-mark plastic volumetric flask. Add 2,5 ml of hydrofluoric aci
33、d (4.1). Dilute to the mark with water and mix. 1 ml of this solution contains 0,1 mg of Nb. BS ISO 13899-2:2005 BS ISO 13899-2:2005 3 4.10 Niobium standard solution, 10 mg/l. Transfer, with a calibrated pipette, 2,5 ml of the niobium stock standard solution (4.8) into a calibrated 250 ml one-mark p
34、lastic volumetric flask. Add 2,5 ml of hydrofluoric acid (4.1). Dilute to the mark with water and mix. 1 ml of this solution contains 0,01 mg of Nb. 4.11 Standard solutions of interfering and matrix elements. Prepare standard solutions for each element above 1 % (mass fraction) in the test sample. U
35、se pure elements or oxides with niobium contents less than 10 g/g (mass fraction). Commercial certified standard solutions can also be used if the niobium content is less than the value specified above. NOTE If a large amount of an element is to be added (e.g. iron), it might be more advantageous to
36、 use the pure metal and weigh the correct amount (see 7.3 and 7.4). In this case, use the dissolution procedure described in 7.1.2. 5 Apparatus As it, for obvious reasons, is impossible to use volumetric glassware in this application, the laboratory has to make sure that the plastic pipettes and fla
37、sks to be used are calibrated in accordance with ISO 648 or ISO 1042 as appropriate. Ordinary laboratory apparatus and 5.1 Atomic emission spectrometer, equipped with an inductively coupled plasma (ICP) and a nebulization system resistant to hydrofluoric acid. When a teflon nebulizer is used, it is
38、recommended that a surface active agent should be added to improve wetting in the nebulizer and spray chamber. Modern nebulizers are, however, often manufactured in plastic materials with better wetting-characteristics than Teflon and can therefore (as is the case with sapphire nebulizers) be used w
39、ithout a surface active agent. The ICP-ES spectrometer used will be satisfactory if, after optimising according to 7.2.1 to 7.2.4, it meets the performance criteria given in 5.1.2 to 5.1.4. The spectrometer can be either the simultaneous or the sequential type. A sequential type can be used either w
40、ith or without an internal standard. However, if a sequential spectrometer is to be used with an internal standard, it shall be fitted with an arrangement which allows for the simultaneous measurement of the internal standard line. 5.1.1 Analytical lines This standard does not specify any particular
41、 emission line. It is mandatory that each laboratory carefully investigate the line/lines available on its own equipment to find the most suitable one regarding sensitivity and freedom from interferences. In Table 1, however, two suggestions are given together with possible interferences. These line
42、s have been carefully investigated (see Annex B). The line for the internal standard element should be selected according to 4.7. It is, however, recommended to use Sc 363.07 nm. This line is interference free for the elements and concentrations given in Annex B. Table 1 Examples of analytical lines
43、 together with interfering elements Element Wavelength nm Possible interferences Nb 309,41 V, Cr, Ni Nb 316,34 Fe, Cr, V, W, Ti 4 5.1.2 Minimum practical resolution of the spectrometer Calculate the bandwidth, according to Clause A.1, for the wavelength used including the line for the internal stand
44、ard. The bandwidth shall be less than 0,030 nm. 5.1.3 Minimum short-term precision Calculate the short-term precision according to Clause A.2. The relative standard deviation shall not exceed 0,5 % of the mean absolute or ratioed intensities for concentrations 100 to 1 000 times the LOD (6.1.4) mg/l
45、. For concentrations 10 to 100 times the LOD, the RSD shall not exceed 5 %. 5.1.4 Limit of Detection (LOD) and Limit of Quantification (LOQ) Calculate the LOD and LOQ, according to Annex A, Clause A.3, for the analytical line used. The values shall be below the values in Table 2. Table 2 Limit of De
46、tection (LOD) and Limit of Quantification (LOQ) Element LOD mg/l LOQ mg/l Nb 0,05 0,25 5.2 Polytetrafluoroethylene (PTFE) beakers 5.3 100 ml polypropylene volumetric flask 6 Sampling and samples Sampling and preparation of the laboratory sample shall be carried out in accordance with ISO 14284 or ap
47、propriate national standards for steels. 7 Procedure 7.1 Preparation of test solution, T n7.1.1 Weigh, to the nearest 0,000 5 g, a test portion of the laboratory sample in accordance with Table 3, and transfer it to a PTFE beaker. Table 3 Test portion Expected content % (mass fraction) Test portion
48、g 0,005 to 0,5 0,5 0,5 to 5 0,25 7.1.2 Add 10 ml of HCl (4.2), 2 ml of HNO 3(4.3) and 5 ml of HF (4.1). Heat to complete dissolution. Make sure that all deposits that may have formed on the walls of the beaker are washed down using a glass stick with a rubber head. Add 20 ml of fuming acid mixture (
49、4.6) and heat until the perchloric acid starts to fume. Continue to fume for 2 to 3 min (the white smoke must be on the top of the PTFE beaker). BS ISO 13899-2:2005 5 7.1.3 Cool the solution and add 10 ml of water to dissolve the salts. Some residues can remain undissolved. Add 2 ml of HF (4.1). Heat slowly for 20 min when the residues will dissolve completely. 7.1.4 Cool the solution to room temperature and transfer th
