GOST R ISO 13899-2-2009

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  ГОСТ Р ИСО 13899-2-2009

GOST R ISO 13899−2-2009 Steel. Determination of molybdenum, niobium and tungsten in alloy steels. Spectrometer of atomic emission with inductively coupled plasma method. Part 2. Determination of niobium

GOST R ISO 13899−2-2009

Group B39

NATIONAL STANDARD OF THE RUSSIAN FEDERATION

Steel

Determination of molybdenum, niobium and tungsten in alloy steels

SPECTROMETER OF ATOMIC EMISSION WITH INDUCTIVELY COUPLED PLASMA METHOD

Part 2

DETERMINATION OF NIOBIUM

Steel. Determination of Mo, Nb and W contents in alloyed steel. Inductively coupled plasma atomic emission spectrometric method. Part 2. Determination of Nb content

OKS 77.080.20
AXTU 0709

Date of introduction 2010−01−01

Preface

The objectives and principles of standardization in the Russian Federation established by the Federal law of 27 December 2002 N 184-FZ «On technical regulation», and rules for the application of national standards of the Russian Federation — GOST R 1.0−2004 «Standardization in the Russian Federation. The main provisions"

Data on standard

1 PREPARED by the Technical Committee for standardization TC 145 «monitoring Methods of steel products» on the basis of an authentic translation of the standard referred to in paragraph 4

2 SUBMITTED by the Technical Committee for standardization TC 145 «monitoring Methods of steel products"

3 APPROVED AND put INTO EFFECT by the Federal Agency for technical regulation and Metrology of April 6, 2009 N 121-St

4 this standard is identical to international standard ISO 13899−2:2005 «Steel. Determination of molybdenum, niobium and tungsten in alloy steels. Spectrometer of atomic emission with inductively coupled plasma method. Part 2. Determination of niobium» (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»).

In applying this standard it is recommended to use instead of the referenced international standards corresponding national standards of the Russian Federation, details of which are given in Appendix E

5 INTRODUCED FOR THE FIRST TIME


Information about the changes to this standard is published in the annually issued reference index «National standards», and the text changes and amendments — in monthly indexes published information «National standards». In case of revision (replacement) or cancellation of this standard a notification will be published in a monthly information index «National standards». Relevant information, notification and lyrics are also posted in the information system of General use — on the official website of the Federal Agency for technical regulation and Metrology on the Internet

1 Scope

This standard specifies the spectrometer of atomic emission with inductively coupled plasma method for the determination of niobium in steels. The method is applicable for determining the mass fraction of niobium in the range of 0.005% to 5%.

2 Normative references

This standard uses the regulatory references to the following standards:

ISO 648:1977 laboratory Glassware. Pipette with one mark

ISO 1042:1983 laboratory Glassware glass. Volumetric flask with one mark

ISO 3696:1987 Water for analysis in laboratories. Specifications and test methods

ISO 5725−1:1994 Accuracy (trueness and precision) of methods and measurement results. Part 1. General provisions and definitions

ISO 5725−2:1994 Accuracy (trueness and precision) of methods and measurement results. Part 2. The basic method for the determination of repeatability and reproducibility of a standard measurement method

ISO 5725−3:1994 Accuracy (trueness and precision) of methods and measurement results. Part 3. Intermediate indicators the precision of a standard measurement method

ISO 14284:1996 Steel and iron. Selection and preparation of samples for chemical analysis

3 the essence of the method

The sample is dissolved in a mixture of hydrochloric, nitric and hydrofluoric acids and evaporated with a mixture of phosphoric and perchloric acids. Add hydrofluoric acid and, if necessary, the solution element as an internal standard. The solution was then diluted to a certain volume. The resulting solution was filtered and sprayed in a plasma atomic emission spectrometer and measure the radiation intensity of the element simultaneously with the measurement of the light emission element internal standard.

Used calibration method based on the selection of solutions for calibration that are similar in composition (matrix) and the content of niobium in the sample. In this way, given the influence matrix, ensuring high accuracy measurements even for samples of high-alloyed steels, where the spectral interference can be significant. All clutter should be kept to a minimum, and therefore used the spectrometer must meet the requirements for the selection of analytical lines.

To carefully choose the right matrix, it is necessary to know the concentration of all elements of the sample with an accuracy of one percent. Therefore, it is necessary to perform a preliminary analysis of the samples in any semi-quantitative method.

4 Reagents

Unless otherwise specified, use reagents of the established analytical purity and distilled water, further purified by distillation or other means.

4.1 Hydrofluoric acid, 40% (mass fraction), a density of 1.14 g/cm.

4.2 Hydrochloric acid density of 1.19 g/cm.

4.3 Nitric acid with density of 1.40 g/cm.

4.4 Phosphoric acid density of 1.70 g/cm, diluted 1:1.

4.5 Perchloric acid with a density of 1.54 g/cm, diluted 1:1.

4.6 acids Mixture for evaporation: mixed 100 cmof phosphoric acid (4.4) and 300 cmof perchloric acid (4.5).

4.7 the Solution of the internal standard concentration of 1000 mg/DM

Choose any element as internal standard prepare a solution with concentration 1000 mg/DM. The internal standard should be pure, not present in the sample and not to overlap with analytical line.

The wave length of the element internal standard should not overlap with the wavelengths of the elements present in the sample solution.

The internal standard must completely dissolve in the acid, forming a precipitate. The excitation conditions and analytical lines and the internal standard should be the same.

4.8 Solution of niobium in a concentration of 1000 mg/DM

Weigh with precision of 0.0001 g to 0.5 g of high-purity niobium with a purity of more than 99.95% and dissolved in mixture: 30 cmhydrofluoric acid and 3 cmof nitric acid. The solution was cooled and quantitatively transferred to a plastic volumetric flask with one mark capacity of 500 cm, was adjusted to the mark with water and mix. 1 cmof this solution contains 1 mg of niobium.

Note — you Cannot use a previously prepared standard solution of niobium for subsequent analyses.

4.9 Solution of niobium in a concentration of 100 mg/DM

Transferred with a calibrated pipette 25 cmof the primary standard solution of niobium (4.8) in a plastic volumetric flask with one mark capacity of 250 cm. Add 2.5 cmhydrofluoric acid (4.1). Bring to mark with water and mix. 1 cmof this solution contains 0.1 mg of niobium.

4.10 Solution of niobium in a concentration of 10 mg/DM

Transferred with a calibrated pipette 2.5 cmprimary standard solution of niobium (4.8) in a plastic volumetric flask with one mark capacity of 250 cm. Add 2.5 cmhydrofluoric acid (4.1), adjusted to the mark with water and mix. 1 cmof this solution contains 0.01 mg of niobium.

4.11 the Solutions interfering and matrix elements

Prepare the standard solutions of each element, the content of which in the sample more than 1% in mass fraction. Use pure elements or oxides with a mass fraction of niobium of less than 10 µg/g. permitted use of solutions of interfering and matrix elements, if the content of niobium is less than that specified above.

Note — If you add a large amount of element (e.g. iron), the advantage should be given to the pure metal and weigh exact number (see 7.3, 7.4). In this case, use the procedure of dissolution in 7.1.2.

5 measuring instruments and accessories

Used plastic pipettes and flasks, should be calibrated in accordance with ISO 648 and ISO 1042.

5.1 Atomic emission spectrometer with inductively coupled plasma and system of dispersion, which is resistant to hydrofluoric acid

When using the Teflon spray is recommended for improving wettability in an atomizer and atomizing chamber to add a surfactant. However, modern dispensers are often made of plastic materials with the best in comparison with Teflon characteristics of wettability and, therefore, they can be used (as in the case of corundum nozzles) without the use of surfactants.

Atomic emission spectrometer with inductively coupled plasma will satisfy the requirements, if after optimization in accordance with 7.2.1−7.2.4 are complied with the criteria referred to in 5.1.2−5.1.4.

The spectrometer can be of any type. Consistent style allows you to work with both internal standard and without it. However, in the case of internal standard spectrometer must have an additional device for simultaneous measurement of analytical lines and the internal standard.

5.1.1 Analytical line

This standard does not mandate the use of specific analytical line. This requires that each laboratory carefully examine the lines available on its equipment, to find the most suitable from the point of view of sensitivity and selectivity.

Table 1 shows two versions of the analytical lines with the indication of possible effects (Appendix C).


Table 1 — Examples of analytical lines and the influence of interfering elements in the determination of niobium

The line element of the internal standard should be selected in accordance with 4.7. However, it is recommended to use the line Sc 363,07 nm. This line is free from the influence of interfering elements and their contents (Appendix C).

5.1.2 Minimum practical resolution of the spectrometer

Expect bandwidth in accordance with A. 1 (Appendix A) for the wavelengths used, including lines for internal standard. Band width should be 0,030 nm.

5.1.3 Minimum short-term precision

Expect short-term precision in accordance with A. 2 (Appendix A).

The relative standard deviation must not exceed 0.5% of the average of the absolute or relative intensities for concentrations of niobium (mg/l) exceeding the detection limit according to 5.1.4 in 100−1000 times. For concentrations exceeding the detection limit 10−100 times, the relative standard deviation must not exceed 5%.

5.1.4 detection Limit (DL) and quantification limit (PKO)

Counting and FFP in accordance with A. 3 (Annex A) for the analytical line. Their values must not exceed the values given in table 2.


Table 2 detection Limit and quantification limit

5.2 Polytetrafluoroethylene plastic (PTFE-glass).

5.3 Polypropylene volumetric flasks with a capacity of 100 cm.

6 Sampling and sample preparation

Sampling and sample preparation — ISO 14284.

7 analysis

7.1 Preparation of sample solution for analysis

7.1.1 Weighed with a precision of 0.0005 g weighed sample in accordance with table 3 and placed in a polytetrafluoroethylene beaker.


Table 3 Linkage of sample

7.1.2 Add 10 cmof hydrochloric acid (4.2), 2 cmof nitric acid (4.3) and 5 cmhydrofluoric acid (4.1) and heating was continued until complete dissolution. The resulting precipitate (plaque) on the walls of glass wash the glass rod with a rubber tip. Add 20 cmof the mixture of acids for evaporation (4.6) and heated until the appearance of fumes of perchloric acid. Continue steaming for 2−3 min (white pair should be at the top of the PTFE-glass).

7.1.3 Cool the solution and add 10 cmof water to dissolve salts. If the precipitate is completely dissolved, then add 2 cmhydrofluoric acid and slowly heated for 20 min until complete dissolution of the precipitate.

7.1.4 Cool the solution to room temperature and transferred quantitatively into a volumetric polypropylene flask (5.3) with a capacity of 100 cm. If you are using internal standard, add 1 cmof a solution of internal standard (4.7). When adding the internal standard it is necessary to carefully ensure that the added volume was exactly the same for each bulb.

7.1.5 the Solution obtained in accordance with 7.1.4, adjusted to the mark with distilled water and mix.

7.1.6 Filter all solutions through a paper filter of medium density, discarding the first 2−3 cm.

7.2 Preparation for spectrometric measurements

7.2.1 Include the spectrometer and heated in accordance with the manual.

7.2.2 optimize the Device in accordance with the manual.

7.2.3 Prepare the software of the spectrometer to measure the intensity of analytical lines, calculate the average and relative standard deviation.

7.2.4 If the use of an internal standard, we prepare the software to calculate the relation between the intensities of the analytical lines of the designated element and the inner element of the standard. The intensity of the line internal standard must be measured simultaneously with the intensity of the analytical line.

7.2.5 the performance Requirements of the spectrometer must match 5.1.2−5.1.4.

7.3 Preliminary analysis of the sample solution

Prepare solutions for calibration or corresponding to the mass fraction of niobium of 0.5% or 5% depending on the expected content and the solution of the matrix corresponding to the sample solution. Prepare also a test of the calibration solution in the same way as the calibration, but without the addition of a solution of niobium.

7.3.1 Add, using a pipette, 2.5 cmof a solution of niobium (4.8) in a polypropylene volumetric flask (5.3) with a capacity of 100 cmwith the mark (corresponds to the content of Nb is 0.5%), or 12.5 cmof a solution of niobium (4.8) in a volumetric flask with a capacity of 100 cm(5.3) with the mark (corresponds to the Nb content of 5%).

7.3.2 To calibration solution or adds all of the elements of the matrix a concentration higher than 1% using standard solutions of (4.11) with an accuracy of 1% internal standard solution (4.7). Calculations should be carried out with the mass of sample sample 0.5 g or 0.25 g.

7.3.3 the second polypropylene volumetric flask with a capacity of 100 cm(5.3) with the add matrix elements (7.3.2) and internal standard (4.7) when using.

7.3.4 In both flasks add 20 cmof the mixture of acids for evaporation (4.6), adjusted to the mark with water and mix.

7.3.5 measuring the absolute or relative intensities of the solutions and or .

7.3.6 measuring the absolute or relative intensity for the sample solution .

7.3.7 estimate the concentration of niobium in the sample solution by interpolation between the absolute or relative intensities of the solutions and or .

7.4 Prepare two calibration solutions and

For each sample prepared according to 7.4.1 and 7.4.2 two are close in the matrix of the calibration solution and with the concentration of niobium in solution is slightly lower and slightly higher than in the solution of the sample.

7.4.1 Use the results obtained in 7.3.7 and estimate the amount of niobium (mg) in a solution of the sample. Added using a calibrated pipette a suitable solution of niobium (4.8, 4.9 or 4.10) into a single PTFE Cup with the mark and the second Cup with the mark .

7.4.2 All matrix elements contained in the sample concentration in excess of 1%, add in standard solution (4.11) in the same amounts as in the matrix (up to 1%) to the calibration solutions and .

7.4.3 Preparation of solutions of samples of steel for the determination of niobium prepared in accordance with 7.1.2 through 7.1.6.

7.5 Determination of niobium in solutions of samples of steel

7.5.1 measuring the absolute or relative intensity of analytical lines of niobium, since the calibration solution with a lower concentration of niobium . Thereafter, the sample solution and the calibration solution with the higher concentration . Repeat the measurement in the specified sequence three times and calculated the average intensity and for the calibration solutions and and to sample solution, respectively.

7.5.2 Build the calibration graph of the measured intensities and the amount of niobium and in the calibration solutions. Determine the amount of niobium in solution samples by interpolation of the measured intensity between and .

8 Determination of results

8.1 Method of calculation

Mass fraction of niobium , %, is calculated by the formula

, (1)

where  — the amount of niobium in the sample solution, mg;

 — the weight of the portion of the sample,

8.2 Precision

Routine testing of the present method was carried out in thirteen laboratories in eleven samples with different content of niobium. Each laboratory performed three to determine each sample (see notes 1 and 2).

Note 1 — Two of the three definitions was performed in the conditions of repeatability according to ISO 5725−1, i.e. one operator on one instrument at identical conditions, run the analysis with a single calibration and minimal time period.

Note 2 — Third determination was carried out at a different time by the same operator as in remark 1, using the same instrument with a new calibration.


The analyzed samples are given in Appendix C.

The obtained results were statistically processed in accordance with ISO 5725.1 — ISO 5725.3. The data show a logarithmic dependence between the content of niobium, limit of repeatability , limit of repeatability and limit of intermediate precision and results of analysis (note 3), as presented in table 4.


Table 4 — results of the limits of repeatability, reproducibility and intermediate precision

Percentage

A graphical representation of the data given in Appendix D.

Note 3 — two values of the mass fraction of niobium produced in the first day, was calculated according to ISO 5725−2 limit of repeatability and limit of reproducibility . On the basis of the values obtained on the first day, and the values obtained on the second day, according to ISO 5725−3 were calculated the limit of intermediate precision .

9 test report

The test report shall contain:

a) information about identification of the sample, the laboratory and date of test;

b) method used with reference to this standard;

c) test results;

d) especially marked when performing tests;

e) any operations not specified in this standard, or any additional operations that may affect the test results.

Annex a (informative). The method of determining the instrumental parameters

Appendix A
(reference)

A. 1 a Practical resolution of the spectrometer

Practical resolution of the spectrometer include: the scanning of the wavelength spectrum including the desired spectral line; identifying profile; measuring a peak width corresponding to the half of its height; the calculation of the resolution in nanometers. An example is given in figure A. 1.

Figure A. 1 — Example of calculation of a practical resolution

Resolution =(213,92−213,80)·=0,016 nm.

Figure A. 1 — Example of calculation of a practical resolution

A. 2 Minimum short-term accuracy

The main parameter of the apparatus for determining is a short-term signal stability issue, namely, the correspondence between the values obtained on the same sample solution during the repeated measurements, quickly following each other.

It is also important the value of the standard deviation of the average result, expressed as a deviation of concentration (relative standard deviation, CCA).

Performing ten successive measurements of the same solution and the calculated relative standard deviation.

A. 3 the detection Limit (DL) and quantification limit (PKO)

Detection limit and quantification limit the analytical parameters of the method, calculations are carried out taking into account standard deviation values of measurements obtained under conditions of repeatability.

Prepare two solutions, one of which does not contain a detectable element (hereinafter, a zero solution) the other contains the designated element with a concentration of ten times the detection limit (hereinafter — the second solution). The solutions should be similar to the analyzed samples at concentrations of acids, floodplains and matrix elements.

Spray a zero solution in approximately 10 and take ten readings of the spectrometer with fixed integration time, the same manipulations are performed with the second solution.

The intensity of the signal received from the zero and second solutions, and calculate the average intensity and standard deviation of the zero member .

True the average intensity for a solution, exceeding the content of ten times the detection limit, determined by the following formula

. (A. 1)

The detection limit is determined by the formula

, (A. 2)

where is the strength of the concentration of a solution in excess of ten times the detection limit, mg/DM.

The quantification limit is calculated by the formula

.

Annex b (informative). The proposed line of niobium and the possible spectral interference from the interfering elements in the determination of niobium in steels by ICP-AES

The App
(reference)

Interference detected on the part of the elements included in the composition of the steel.

Quantitative characterization of the influence of related items expressed in the apparent contents of niobium corresponding to the contents of interfering elements in table B. 1.


Table B. 1 — Possible spectral interference in the determination of niobium

Application (reference). More information on international testing

Application
(reference)

Table 4 of this standard reflects the analytical results of two international trials. The first was conducted on six samples in seven countries, including 12 laboratories, a second test was conducted on five samples in seven countries, including 13 laboratories.

The results were presented in the regulations.

Used in the testing of the control samples and the results are shown in tables C. 1 and C. 2, respectively.

Graphical representation of precision data are given in Appendix D.


Table C. 1 — Control samples used in the interlaboratory tests

Table C. 2 — Results of interlaboratory tests

Annex D (informative). Graphical representation of precision data

Appendix D
(reference)

Figure D. 1 is a Logarithmic dependence between the content of niobium and limit of repeatability r and reproducibility limits R (W) and R

 — 1,9034;

 — 1,6553;

 — Of 1.3984,

where  — the average content of niobium (mass fraction), %, obtained on the basis of three definitions, each laboratory;

 — the contents of niobium (mass fraction), %;

 — precision (mass fraction), %.

Figure D. 1 is a Logarithmic dependence between the content of niobium and limit of repeatability or reproducibility limits and

Annex E (informative). Data on compliance with national standards of the Russian Federation the reference to international standards

Annex E
(reference)

Table E. 1