GOST R 51056-97

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  ГОСТ Р 51056-97

GOST R 51056−97 Steel alloyed and high alloy. Atomic emission spectral method for the determination of tungsten and molybdenum

GOST R 51056−97

Group B39

STATE STANDARD OF THE RUSSIAN FEDERATION

STEEL ALLOYED AND HIGH-ALLOYED

Atomic emission spectral method for the determination of tungsten
and molybdenum

Alloyed and high-alloyed steels.
Atomic emission spectrometry method for determination of tungsten
and molybdenum

OKS 77.040*
AXTU 0709
____________________
* In the index «National standards», 2008
OKS 77.080.20. — Note the manufacturer’s database.

Date of introduction 1998−01−01

Preface

1 DEVELOPED AND SUBMITTED by the Technical Committee TC 145 «monitoring Methods of steel products"

2 ADOPTED AND put INTO EFFECT by the Resolution of Gosstandart of Russia of June 2, 1997 No. 203

3 INTRODUCED FOR THE FIRST TIME

1 SCOPE

This standard specifies atomic emission (with excitation in inductively coupled plasma) method for determination of molybdenum and tungsten in alloyed and high-alloyed steels in the range of 0.01−5.0%.

The method is based on measuring the intensity of emission of atoms of tungsten and molybdenum with the introduction of the sample solution into an excitation source.

2 NORMATIVE REFERENCES

The present standard features references to the following standards:

GOST 3118−77 hydrochloric Acid. Specifications

GOST 4204−77 sulfuric Acid. Specifications

GOST 4461−77 nitric Acid. Specifications

GOST 6552−80 orthophosphoric Acid. Specifications

GOST 6709−72 distilled Water. Specifications

GOST 10157−79 Argon gaseous and liquid. Specifications

GOST 12349−83 Steel alloyed and high alloy. Methods for determination of tungsten

GOST 13610−79 carbonyl Iron radio. Specifications

GOST 18289−78 Sodium volframovich 2 water. Specifications

GOST 28473−90 Iron, steel, ferroalloys, chromium and manganese metal. General requirements for methods of analysis

3 GENERAL REQUIREMENTS

General requirements for method of analysis according to GOST 28473.

4 EQUIPMENT, REAGENTS, SOLUTIONS

Standard spectrometric system consisting of a spectrometer (multi-channel or sequential scanning), tripod excitation, high-frequency generator, the measuring electronic system and computer.

Argon according to GOST 10157.

Hydrochloric acid according to GOST 3118 and a solution of 1:9.

Nitric acid according to GOST 4461 and a solution of 1:1.

Orthophosphoric acid according to GOST 6552.

Sulfuric acid according to GOST 4204, and a solution of 1:1.

Distilled water according to GOST 6709.

A mixture of acids: 300 cmof distilled water, 150 cmof phosphoric acid, 150 cmof nitric acid and 300 cmof hydrochloric acid stir gently.

Carbonyl iron according to GOST 13610.

Molybdenum metal brand MCIT.

Standard solutions of molybdenum:

Solution N 1. 1 g of metallic molybdenum is dissolved in 20 cmof nitric acid (1:1) and 20 cmof sulphuric acid (1:1). The solution was evaporated to fumes of sulfuric acid, add 100 cmof water and heated to dissolve the salts. After cooling, the solution is transferred to a volumetric flask with a capacity of 1 DM, adjusted to the mark with water and mix. Standard solution 1 contains N 1 cm1 mg of molybdenum.

A Solution Of N 2. 10 cmstandard solution N 1 is transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix. Standard solution No. 2 contains a 1 cm100 mcg of molybdenum.

Sodium volframovich 2-water according to GOST 18289.

Standard solutions of tungsten:

Solution N 3. 1,7942 volframovich g of sodium is dissolved in a volumetric flask with a capacity of 1 DMin a small amount of water, bring to the mark with water and mix. Standard solution No. 3 contains a 1 cm1 mg of tungsten. The titer of the obtained solution set by the gravimetric method according to GOST 12349.

A Solution Of N 4. 10 cmof the solution No. 3 is transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix. Standard solution No. 4 contains 1 cm100 micrograms of tungsten.

A Solution Of N 5. In a volumetric flask with a capacity of 100 cmmaking shown in table 1 are the volumes of standard solutions N 1 and 3, hydrochloric acid solution (1:9) bring to mark and mix. Standard solution No. 5 contains of 1 cmto 10 micrograms of tungsten and molybdenum.


Table 1 — Composition of solutions for monitoring the stability of calibration parameters

5 PREPARING FOR ANALYSIS

5.1 preparing the instrument for measurements carried out in accordance with the instructions for its use and maintenance. Instrumental parameters of the device and flows of argon is set in the range that the maximum sensitivity of the determination of tungsten and molybdenum.

5.2 establishing the calibration parameters is performed according to the solution and 5 N hydrochloric acid solution (1:9). For each solution perform at least five measurements of the intensities of tungsten (at the analytical line wavelength 207,91 or 218,94 nm) and molybdenum (analytical line wavelength 202,03 or 203,84 nm). According to the average values of the intensities of the calculated parameters calibration parameters. When determining the calibration characteristics of the mass fraction of tungsten and molybdenum is expressed as a percentage in accordance with the values given in table 1. Parameters calibration parameters recorded in the computer memory.

The use of other analytical lines, if they provide the definition of a mass fraction of tungsten and molybdenum in the required range with the accuracy stipulated in this standard.

The use of other methods of determining the parameters of the calibration parameters, if available mathematical software spectrometer setup.

5.3 the analysis of the steels with a mass fraction of tungsten and molybdenum, from 0.01 to 1.0% suspension of the sample mass 0,1000 g placed in a beaker with a capacity of 150 cm, 30 cm adda freshly prepared mixture of acids, cover with a watch glass and heated until complete dissolution of the sample. The solution was cooled, washed the walls of the beaker and watch glass with distilled water, quantitatively transferred to a volumetric flask with a capacity of 100 cm, adjusted with distilled water to the mark and mix. The resulting solution contains 1 cm1 mg sample of the sample steel.

In the analysis of the steels with a mass fraction of tungsten and molybdenum in the range from 1.0 to 5.0% in a volumetric flask with a capacity of 50 cmadd 5 cmof the resulting solution, adjusted with hydrochloric acid (1:9) to the mark and mix. The thus obtained solution contains 100 µg of sample sample 1 cm.

Allow the use of other methods of dissolution of batches of steels, providing a complete decomposition of the sample and does not require changes in further stages of analysis

.

5.4 dissolution of the sample state standard samples (GSO), similar in chemical composition to the analysed samples, carried out in accordance with 5.3.

5.5 in Parallel with the dissolution of the sample, performing all operations of the methods and using the same quantities of reagents, carry out a test to based on the content of tungsten and molybdenum in the reagents.

5.6 Preparation of solutions used to control the stability of the calibration parameters

5.6.1 Two hinges of iron, weighing 0.09 g each, placed in two cups, dissolved in 5.3 and transferred to volumetric flasks with a capacity of 100 cm. There is introduced shown in table 1 are the volumes of standard solutions (N 1, 3, and 2, 4), adjusted to the mark with water and mix. The thus obtained solutions A and B (regulirovanie solutions) is used to control the stability of the calibration parameters in the analysis of the steels with a mass fraction of tungsten and molybdenum in the range from 0.010 to 1.00%.

5.6.2 In two volumetric flasks with a capacity of 100 cm tomake 10 cmof the solution in the reference experiment and shown in table 1 are the volumes of standard solutions (N 1, 3, and 2, 4), adjusted with hydrochloric acid (1:9) to the mark and mix. So get regulirovanie solutions C and d, which are used to control the stability of the calibration parameters in the analysis of the steels with a mass fraction of tungsten and molybdenum in the range from 1.0 to 5.0%.

Regulirovanie the solutions were prepared with each batch of analyzed samples.

To prepare the entire series of solutions of analyzed samples of the bonds, the control of experience and recalibrating solutions using reagents from the same batch.

6 ANALYSIS

6.1 stability Control calibration parameters (recalibration) is performed before starting the measurement in accordance with the mathematical software tool. For control stability at the top of the range used regulirovanie solutions A and b, and at the bottom respectively regulirovanie solutions B and d in the analysis of the steels with a mass fraction of tungsten and molybdenum, are listed in table 1. For this purpose, conduct 3−5 measurements of the intensities of tungsten and molybdenum on the chosen analytical lines, spraying in plasma the corresponding regulirovanii solution.

Allow to use other methods of monitoring the stability of calibration parameters under mathematical software spectrometer setup.

6.2 Control of the correctness of the results of the analysis carried out by measurement of the mass fraction of tungsten and molybdenum in a solution of the bonds at 5.4.

In plasma spraying the appropriate solution, carry out three parallel measurements. The mass fraction that represents the average result of these measurements, is one of parallel measurements certified value of tungsten and molybdenum in GSO.

The average value of the two thus obtained parallel definitions mass fraction of tungsten and molybdenum should not vary from certified more than allowable value given in table 2. Otherwise, repeat the recalibration.


Table 2 — Norms of accuracy and norms of accuracy control of determination of mass fractions of tungsten and molybdenum

Percentage

6.3 measurement of the mass fraction of tungsten and molybdenum is carried out for each solution analyzed samples similar to the procedure specified in 6.2. With this purpose, is sprayed into the plasma solutions the mass concentration of 1 mg/cmin the analysis of the steels with a mass fraction of tungsten and molybdenum, up to 1.00% and solution concentration of 100 µg/cmin the analysis of the steels with a mass fraction of tungsten and molybdenum from 1.00 to 5.0%.

6.4. After each measurement the system was washed by spraying hydrochloric acid solution (1:9).

7 PROCESSING OF RESULTS

7.1 Mass percent of tungsten and molybdenum in the sample in % is calculated by the formula

, (1)

where  — mass fraction of tungsten and molybdenum in the solution of the sample, %;

 — weight of steel contained in 1 cmof solution, mg.

The final result of the analysis be the arithmetic mean of two parallel definitions for the two test portions of the test sample.

7.2 Standards of accuracy and standards for monitoring the accuracy of determining the mass fraction of tungsten and molybdenum are shown in table 2.

7.3 allowable Absolute discrepancies in the results of parallel measurements at p = 0.95 does not exceed the permissible differences for the respective concentrations shown in table 2. If you get results with differences more acceptable the analysis should be repeated using a new sample of the analyzed sample. If re-analysis of the differences between the results of parallel measurements once again exceeds the limit, the sample is rejected and replaced with a new.