GOST 21639.0-93

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  ГОСТ 21639.0-93

GOST 21639.0−93 Fluxes for electroslag remelting. General requirements for methods of analysis

GOST 21639.0−93

Group B09

INTERSTATE STANDARD

Fluxes for electroslag remelting

GENERAL REQUIREMENTS FOR METHODS OF ANALYSIS

Fluxes for electroslag remelting.
General requirements for methods of analysis.

OKS 71.040.040*
AXTU 0709

________________

* In the index «National standards» 2006 ACS 25.160.20. -

Note the «CODE».

Date of introduction 1996−01−01

Preface

1 PREPARED by the Russian Federation Technical Committee TC 145 «monitoring Methods of steel products"

SUBMITTED by the Technical Secretariat of the Interstate Council for standardization, Metrology and certification

2 ADOPTED by the Interstate Council for standardization, Metrology and certification 17 February 1993.

The adoption voted:

3 Decree of the Russian Federation Committee on standardization, Metrology and certification from 14.06.95 No. 296 of interstate standard GOST 21639.0−93 introduced directly as state standard of the Russian Federation from January 1, 1996

4 REPLACE GOST 21639.0−76

1 SCOPE

This standard establishes General requirements for methods of analysis of fluxes for electroslag remelting.

2 NORMATIVE REFERENCES

The present standard features references to the following standards:

GOST 8.234−77 GSI. Measures the capacity of glass. Methods and means of verification

GOST 1770−74 laboratory Glassware measuring glass. Cylinders, beakers, flasks, test tubes. Specifications

GOST 6563−75 technical articles made of noble metals and alloys. Specifications

GOST 6709−72 distilled Water. Specifications

GOST 9147−80 Glassware and equipment lab porcelain. Specifications

GOST 29169−91 oils. Pipette with one mark

GOST 29252−91 oils. Part 2. Burettes without waiting time

GOST 24104−88 laboratory Scales General purpose and model. General specifications*
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* On the territory of the Russian Federation GOST 24104−2001, hereinafter. — Note the CODE.

3 GENERAL REQUIREMENTS

3.1 Samples for analysis are selected and prepared according to normative-technical documentation for methods of sampling and sample preparation of appropriate materials.

3.2. Laboratory measuring utensils and appliances — according to GOST 1770, 29169 GOST, GOST 29252. Allowed the use of volumetric glassware, charge d GOST 8.234. The required accuracy of volume measurement result to the standard methods of analysis.

Crucibles cups and platinum — according to GOST 6563.

Cup stekloproduct SU-2000.

The porcelain crucibles and boats according to GOST 9147.

3.3 reagents Used should have a purity not lower than h. d. a., if not provided the other requirements in the standard methods of analysis.

Standard solutions were prepared from reagent qualification not lower than H. h or a metal with a mass fraction of the main element at least 99.9% (if not indicated otherwise in the standards for methods of analysis). The need to establish the mass concentration of the standard solutions specified in the standard methods of analysis. Allow setting of the mass concentration of standard solutions for the standard sample.

3.4 For the preparation of aqueous solutions and the analysis necessary to apply distilled water according to GOST 6709, unless stipulated other requirements in the standard methods of analysis.

3.5 the Concentration of prepared solutions Express:

mass concentration (g/DMg/cm);

molar concentration (mol/DM);

molar concentration of equivalent (mol/DM).

Mass fraction — the mass of substance in grams referred to 100 g of solution or 100 g of substance (%).

The contents of the element fluxes are expressed in mass fraction (%).

3.6 the Degree of dilution of acids and indicate solutions in the form of A In, for example, 1:4, where A is the volumetric part of the dilute reagent, volume of the used solvent. If the standard method of analysis not specified the concentration of the acid or an aqueous solution of ammonia, then use concentrated acid or concentrated aqueous ammonia solution.

3.7 the Terms «warm» or «hot» water (or solution) means that the fluid has a temperature of 40−75 °C or 75 °C, respectively. If required, the temperature specified in the standard methods of analysis.

3.8 Mass concentration of titrated solutions establish not less than three portions (or aliquots) of the initial substance and rounded with accuracy up to four significant digits.

3.9 Weighing the sample sample precipitation and substances for the preparation of standard solutions is carried out on the laboratory scales General purpose according to GOST 24104 2nd accuracy class with the largest weighing limit of 200 g or on any other scales that meets the specified requirements for their metrological characteristics. The necessary precision of weighing result in the standard methods of analysis.

3.10 by photometric methods, the thickness of the light-absorbing layer in cuvettes must be selected so as to obtain an optimal light absorption for a solution of the corresponding coloured connections with regard to the type of the used device.

3.11 Calibration curve built in the system of rectangular coordinates: the abscissa shows the delay numeric value of the concentration or mass fraction of an element or the mass of the element and the axis of ordinates the value of the analytical signal.

How to build a calibration curve indicated in the specific standard on the method of analysis. Use the method of comparing the analytical signal of the sample with the analytical signal of standard solution of the element or of the solution of a standard sample.

3.12 in determining atomic absorbtional method, the range of linearity of the calibration graphs depends on the sensitivity of the employed equipment, therefore we offer masses of elements in the samples for constructing the calibration graphs to consider the recommended.

3.13 the Mass percent of each element in the sample is determined in parallel (or independently) in two batches. The differences in the assessment of the quality of the material analysis is carried out in three batches.

At least once per shift (when using the same reagent) under the same conditions is carried out two test experience for inclusion in the analysis of the amendments, taking into account the mass fraction of the element in the reactants.

3.14 for the purpose of control error of middle result of the analysis at least once per shift under the same conditions analyze the standard sample in two (three) batches. For control choose a standard sample with a chemical composition corresponding to the requirements of standard methods of analysis of this element.

3.15 For the results of the analysis of samples or standard sample and take the arithmetic average of the results of the parallel (or independent) definitions taking into account the average value of the results of the control experiments.

3.16 Error analysis result (at p = 0.95) will not exceed the limit in percent, is given in the relevant standard methods of analysis of the mass fraction of the element when the following conditions are met:

the discrepancy between the results of two (three) parallel (independent) of the definitions shall not exceed (at p = 0.95) values are % given in the relevant standard methods of analysis of the mass fraction of the element;

played in the standard sample, the value of the mass fraction of the element must not vary from certified more than acceptable at a confidence level of 0.85, the value in % is given in the relevant standard method of analysis of the mass fraction of the element.

If any of the above conditions, a second analysis in accordance with 3.13. If and when re-analysis of the accuracy requirements of the results are not met, the results of the analysis to recognize the unfaithful, the analysis is stopped until the identification and elimination of the causes of the disruption of the analysis.

The divergence of the two middle results of the analysis, obtained under different conditions should not exceed (at p = 0.95) values are % given in the relevant standard methods of analysis of the mass fraction of the element.

3.17 the Numerical value of the result of the analysis must end with the same number of discharges, and the corresponding error value .

3.18 Numerical value of error and standards for the control of accuracy is allowed to Express one significant figure.

3.19 in the absence of the standard sample and the control error of middle result of the analysis carried out by the method of additives or other methods.

Monitoring the error of the average result by the method of additions is carried out by finding the mass fraction of the element in the analyzed material after adding an appropriate sample of pure metal or aliquote part of a standard solution of this component to the sample of analyte prior to analysis. The amount of additives is chosen so to keep the optimum conditions of analysis provided by a particular standard methods of analysis. Carry out the determination of this element in the sample after the introduction of additives. The amount of additive is calculated as the difference between the found value of the mass fraction of the element in the sample with the additive and without the additive.

The error of the average result analysis will not exceed the limit , if the found value differs from the calculated Supplement, no more than , where and are taken from the relevant standard method of analysis for values of the mass fraction of the controlled element in the sample and in the sample with the additive.