GOST 27809-95

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  ГОСТ 27809-95

GOST 27809−95 Cast iron and steel. Methods for spectrographic analysis

GOST 27809−95

Group B09

INTERSTATE STANDARD

CAST IRON AND STEEL

Methods for spectrographic analysis

Cast iron and steel.
Methods of spectrographic analysis

OKS 77.080
AXTU 0809

Date of introduction 1997−07−01

Preface

1 DEVELOPED by the Ukrainian scientific-research Institute of metals

SUBMITTED to the State Committee of Ukraine for standardization, Metrology and certification

2 ADOPTED by the Interstate Council for standardization, Metrology and certification (EASC Protocol No. 7 of April 26, 1995)

The adoption voted:

3 Decree of the Russian Federation Committee on standardization, Metrology and certification dated June 19, 1996 N 405 interstate standard GOST 27809−95 introduced directly as state standard of the Russian Federation from January 1, 1997

4 REPLACE GOST 27809−88

1 SCOPE

This standard specifies the spectrographic methods for the determination in the iron and steel mass fraction of elements:

The method is based on excitation of atoms of the elements of cast iron or steel by electric arc discharge of alternating current at atmospheric or reduced pressure air discharge high voltage spark at atmospheric pressure, decomposition of the radiation into a spectrum, check the spectrum on the photographic plate, the density of the blackening of analytical spectral lines of the controlled elements and lines of comparison of iron, the calculation of the density difference of the blackening of these lines and subsequent determination of mass fractions of elements using the calibration graphs.

Standard suitable for certification purposes.

2 NORMATIVE REFERENCES

The present standard features references to the following standards:

GOST 8.010−90 GSI. Methods of measurement

GOST 8.315−91 GSI. The standard samples. The main provisions of the

GOST 8.326−89 Metrological support the development, manufacture and operation of non-standardized means of measurement. The main provisions of the

GOST 12.1.019−79 SSBT. Electrical safety. General requirements and nomenclature of types of protection

GOST 12.1.030−81 OCCUPATIONAL SAFETY STANDARDS. Electrical safety. Protective grounding, neutral earthing

GOST 12.2.007.0−75 SSBT. Products electrical. General safety requirements

GOST 83−79 Sodium carbonate. Specifications

GOST 195−77 Sodium sulfate. Specifications

The Copper GOST 859−78. Brand

GOST 1535−91 copper Rods. Specifications

GOST 2424−83 grinding wheels. Specifications

GOST 3773−72 Ammonium chloride. Specifications

GOST 4160−74 Potassium bromide. Specifications

GOST 4784−74 Aluminum and aluminum deformable alloys. Brand

GOST 6456−82 emery Cloth sanding paper. Specifications

GOST 7565−81 Iron, steel and alloys. Methods of sampling for the determination of chemical composition

GOST 19627−74 Hydroquinone (paradoxians). Specifications

GOST 21400−75 Glass chemical laboratory. Technical requirements. Test methods

GOST 27068−86 Chernovetskiy Sodium (sodium thiosulfate) 5-water. Specifications

3 GENERAL REQUIREMENTS

3.1 the analysis used spectrographs, arc, and spark excitation sources of the spectrum, microphotometry and other equipment, ensuring the accuracy of the analysis required by this standard. Non-standardized means of measuring must be certified according to GOST 8.326.

3.2 Calibration graphs built by the method of «three standards» or other methods, postponing the abscissa shows the logarithm of the mass fraction of the element, and the ordinate is the difference in the density of the blackening of analytical lines and comparison to standard samples.

3.3 For each spectrogram corresponding to the sample for each element using a calibration curve constructed in accordance with 3.2, determine the value of the mass fraction of the element. The average value of the mass fraction for the two (three) spectrograms taken for the result of spectral analysis.

The numerical value of the result of analysis of sample and standard sample should contain the last significant digit in the same category in which it is in the corresponding limit of error .

4 SELECTION AND PREPARATION OF SAMPLES

4.1 Sampling and sample preparation — according to GOST 7565.

4.2 Surface samples prepared for analysis, sharpen on the plane. On the surface are not permitted shells, slag inclusions, color tint and other defects.

5 EQUIPMENT, MATERIALS AND REAGENTS

5.1 Quartz spectrograph of medium or high variance, which allows to obtain spectra in the wavelength range from 230 to 420 nm.

Quartz stepped attenuator.

Arc generator of alternating current (arc AC).

Generator high-voltage spark (high voltage sparks).

Microphotometer.

Spectromancer.

Cutting-off machines.

Grinding (Stripping, sanding) machine.

Elektrokorundovye grinding wheels with ceramic bond, hardness ST-2, size 300х40х70 mm according to GOST 2424.

Emery cloth sanding paper-type SB-200 grit 40−50 GOST 6456.

Universal machine for sharpening electrodes.

Screw-cutting lathe.

Permanent electrodes — carbon spectral clean the rods with a diameter of 6 mm grades C2, C3, copper rods with a diameter of 6 mm according to GOST 1535 marks M00, M1, M2 according to GOST 859, the aluminum rods are 6 mm in diameter grade BP-1 according to GOST 4784, tungsten rods with a diameter of 4−8 mm.

Glass and metal templates with a thickness of 1,5; 2,0 mm.

Sets of standard samples — GEO, CCA, SOP.

Camera-tripod — mounting design Ukrniimet for analysis at reduced air pressure. The scheme and description of installation is given in Appendix B.

Vacuum pump type WNVR-5ДН.

The pressure-vacuum gauge.

Vacuum valves two-way and three-way.

Spectrographic plates of types 1, 2, 3, ES, UFS, PFS-02.

Potassium bromide according to GOST 4160.

Hydroquinone according to GOST 19627.

Sanitarily anhydrous sodium GOST 195.

Metol (parametermanager).

Sodium carbonate according to GOST 83.

Ammonium chloride according to GOST 3773.

Chernovetskiy sodium (sodium thiosulfate) 5-water according to GOST 27068.

Developer:

Solution 1

Solution 2

Binder:

5.2 permitted to use other equipment, equipment and materials ensuring the accuracy of the analysis required by this standard.

6 PREPARATION FOR MEASUREMENTS

6.1 Preparing the instrument for measurements carried out according to the instructions for maintenance and operation of the equipment.

6.2 Permanent electrodes sharpened to a truncated cone at an angle of 90° with the diameter of the via pad 1.5−2.0 mm or hemisphere with a radius of curvature of 3−4 mm.

6.3 Calibration graphs built by the method of «three standards» or a control standard with the use of standard samples category, GEO, CCA, SOP corresponding to the samples in composition and physico-chemical properties and are certified by GOST 8.315 or homogeneous samples analyzed by standardized or certified methods of chemical analysis with known accuracy rate. Allowed in the calibration use that is different from the analyzed samples for physico-chemical properties, subject to the amendments in the results of the analysis.

7 PERFORMANCE MEASUREMENT

7.1 a Sample or a standard sample and a constant electrode secured to the electrode holders. The distance between them are installed using a template, shadow projection, or by reading on the scale of the handwheel from the moment of contact of the electrodes.

7.2 slit of a spectrograph light from a light source using a single lens or three-lens Achromat system.

If necessary, before the slit of the quartz spectrograph to put a stepped attenuator.

7.3 at work on a method of «three standards» are photographed in the same conditions as two (three) times on the spectrograph spectra of samples and standard samples (standards) on a single photographic plate. The order of photographing spectra randomizer.

7.4 If you are working on a method of control of benchmark multiple times on one or more photos in the same conditions as photographing the spectra of standard samples (the standards), one of which is for reference. Spectra of samples and reference standard photograph two (three) times on another photographic plate.

7.5 In the spectrogram on the plate reach the desired region of the spectrum, the spectral lines of elements and using microphotometry measure the density of blackening. The recommended wavelengths of spectral lines and values of mass fraction of detectable elements are shown in table 1.

Line Si 250,69 nm used in the absence of vanadium, and Si 251,61 nm — in the absence of vanadium and titanium.


Table 1

In the determination of boron in steel is used in line comparison 249,65 Fe nm in the iron — 249,82 nm. In the determination of cerium in steels used line comparison 320,25 Fe nm, iron — Fe 319,11 nm. Line CE 320,17 nm used in the absence of titanium and vanadium, the line CE 399,92 nm when the mass fraction of titanium less than 0.2%. Line of molybdenum 281,6 nm is used for the mass fraction of aluminum of not more than 0.1%.

7.6 Performing analysis with the use of an electric discharge arc AC at atmospheric pressure air

7.6.1 Conducted measurement mass fraction of elements:

The conditions of analysis are given in Appendix A (table A. 1).

7.7 Performing analysis with the use of an electric discharge arc AC at reduced air pressure

7.7.1 are measuring mass fraction of elements:

7.7.2 description of the installation for analysis with the use of an electric discharge arc AC at a reduced pressure of air are given in Appendix B.

7.7.3 Conditions the analysis given in Appendix A (table A. 2).

7.8 Performing analysis with the use of electrical discharge of high voltage sparks at atmospheric pressure air

7.8.1 are measuring mass fraction of elements:

7.8.2 Conditions of analysis given in Appendix A (table A. 3).

8 PROCESSING OF RESULTS

8.1 For each element in each spectrogram samples and standard samples, calculate the difference in the density of the blackening of analytical lines and comparison lines

. (1)

8.2 According to the spectrograms of standard samples for each element calculate the arithmetic mean

two (three) values .

8.3 On average values for standard samples and the logarithm of the mass fraction of element build the calibration curve using the three standards or the method of control of standard.

8.4 For each spectrogram of the sample with a calibration chart, determine the value of the mass fraction of each element. The average value of the two (three) of parallel measurements taken for the result of the analysis.

Allowed to pre-averaging of the differences of density of pochernenija calculated for individual spectrograms of the samples with subsequent determination of the result of the analysis on these average values using the calibration curve constructed in accordance with 7.3. When determining the mass fraction of elements on the average difference in density pucherani permissible divergence of parallel measurements should be expressed in units of the density of pucherani using the calibration curve.

8.5 the Value of the mass fraction of the element in the sample of iron or steel, represented by three samples, find the arithmetic average of three measurements obtained one measurement (one spectrogram) of each sample. The permissible discrepancy between the results of these measurements should not exceed (tables 2, 3). In case of exceeding the determined value of the mass fraction of the element in two (three) parallel measurements for each sample. Results are given for each sample separately.


Table 2

Table 3 *

9 NORMS OF ACCURACY OF MEASUREMENTS AND OPERATIONAL MONITORING OF THEIR COMPLIANCE

9.1 Error analysis result (at p = 0.95) does not exceed the limit given in tables 2 and 3, when the conditions are met: the discrepancy between the results of two (three) parallel dimensions should not exceed (at p = 0.95) values , are shown in tables 2 and 3; reproduced in a 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) value , are shown in tables 2 and 3.

If any of the above conditions, the measurement is discontinued and a second to define the parameters of calibration characteristics.

The divergence of the two middle results of an analysis performed under different conditions (for example, when the control intralaboratory reproducibility) shall not exceed (at p = 0.95) values , are shown in tables 2 and 3.

9.2 Standards of accuracy for measuring the mass fraction of the elements in the iron and steel (except of silicon and manganese in cast iron) are given in table 2.

9.3 Standards of accuracy for measuring the mass fraction of silicon and manganese in cast iron are given in table 3.

9.4 stability Control of analysis results

To control the position calibration curve when performing the analysis according to the method of control of Etalon calculate the average value for the control reference on the main plate and the photographic plate where the photographed spectra of samples based on the contrast.

If the difference , expressed in units of mass fraction of the element does not exceed the permissible value of 0.5 (table 2, 3), the measurement is performed on the main schedule. If this difference is greater than 0.5 , the measurement is performed in parallel to the calibration schedule is drawn through the point value .

9.5 Control of reproducibility of analysis results

9.5.1 Control the reproducibility of the results of spectrographic analysis, a second determination of the mass fraction of controlled elements in the previously analyzed samples at least once per quarter.

9.5.2 the Number of re-definitions should be not less than 0.3% of the total number of definitions.

9.5.3 If the discrepancy between the results of initial and repeat analysis exceeds the allowable value (tables 2, 3) is not more than 5% of cases, the repeatability is considered satisfactory.

9.6 the Control of correctness of analysis results

9.6.1 Control of the correctness of the results of the spectrographic analysis performed by selective comparison with the results of chemical analysis performed standardized or certified in accordance with GOST 8.010 techniques at least once a quarter.

9.6.2 the Number of monitored results of spectral analysis are installed in accordance with 9.5.2.

9.6.3 the correctness of the definitions is considered satisfactory if the number of mismatches spectrographic and chemical analysis, exceeding permitted value (tables 2, 3), not more than 5%.

You can control the correctness of photoelectric spectral and x-ray methods of analysis. In this case, the permissible difference shall not exceed (tables 2, 3).

Allowed to inspect the correctness of the method for spectrographic analysis on the basis of reproduced values of the mass fraction of the component in GEO, CCA, SOP, appropriate samples according to the chemical composition and physico-chemical properties. When this played in GSO, OSO, SOP the value of the mass fraction of the component must not vary from certified more than permissible value (tables 2, 3).

When disagreement in assessing the quality of steel and iron control of the correctness of the spectrographic analysis performed by comparison with chemical analysis results.

10 SECURITY REQUIREMENTS

Safety requirements — according to GOST 12.1.019, GOST 12.1.030, GOST 12.2.007.0.

Annex a (recommended). THE CONDITIONS OF ANALYSIS

APPENDIX A
(recommended)

Table A. 1

Table A. 2

Table A. 3

APPENDIX B (recommended). THE INSTALLATION FOR PERFORMING TESTS UNDER REDUCED AIR PRESSURE

APPENDIX B
(recommended)

Elements of the installation are: the camera-the tripod design of the Ukrainian research Institute of metals, vacuum pump, pressure-vacuum gauge. Installation diagram is shown in figure B. 1. Camera tripod consists of a metal table 1 with the outlet for air exhaust 2, rack 3 with electrode holders and glass or metal hood 4. The wall of the cap soldered quartz window 5 for the passage of radiation from the source 6 located on the optical axis of the device. Cap glass with Welt and button made of glass XV-II according to GOST 21400 following dimensions: the diameter of the cap 200 mm, height 250 mm diameter 250 mm, height 260 mm. the dimensions of the metal cap are the same as glass.

Figure B. 1 diagram of the installation for performing tests under reduced air pressure

The camera tripod mounted on the rail of the spectrograph. Table-tripod with the sample and the electrode (figure B. 1) lay cap, open the valve 9 and include a vacuum pump 7. The camera creates a predetermined vacuum. After reaching a predetermined vacuum chamber is disconnected from the vacuum system, blocking the vacuum valve 9, and photographed spectra. The pump is then shut down and open the valve 10 for the admission of air into the pump. Rarefaction of air in the chamber controlled with pressure-vacuum gauge 8.