GOST 20068.2-79

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  ГОСТ 20068.2-79

GOST 20068.2−79 Bronze without tin. Method of spectral analysis on a metal standard samples with photoelectric spectra (with Amendments No. 1, 2)

GOST 20068.2−79

Group B59

INTERSTATE STANDARD

BRONZE WITHOUT TIN

Method of spectral analysis on a metal standard
samples with photovoltaic spectra

Tinless bronze. Method of spectral analysis of metal
standard specimens with spectrum photo-electric record

AXTU 1709

Date of introduction 1980−07−01

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 29.10.79 N 4102

3. REPLACE GOST 20068.2−74

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Limitation of actions taken by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (ICS 11−95)

6. EDITION with Amendments No. 1, 2 approved in June 1984, November 1989 (IUS 9−82, 2−90)


This standard applies to the tin-free bronze stamps Bra5, Bra7, Bramc9−2, Bramc10−2, Brazhmc10−3-1,5, Brazhn10−4-4, Brazhnmc9−4-4−1, Brkmc3−1, Brb2, Brbnt1,7, Brbnt1,9, Brkd1, Brkh-1, Brazh9−4, and Brkn1−3 according to GOST 18175 and sets the method of spectral analysis on a metal standard samples (SS) with photoelectric registration of spectrum.

The method is based on the excitation spectrum of the unipolar arc discharge, or low-voltage spark discharge or arc discharge AC followed by registration of its optical quantometer. The method allows to determine the bronze, iron, Nickel, manganese, zinc, tin, lead, arsenic, aluminium, silicon, titanium, beryllium, cadmium in the range of mass fraction, indicated in the table.1.

Table 1

The range of detectable concentrations of the elements according to
the grade of alloy

The precision and reproducibility of the results is characterized by the values of the permissible differences given in table.2, at a confidence level =0,95.

Table 2

Notes:

1. When verifying compliance with established standards of permissible differences of the two results of parallel measurements for the taking the arithmetic mean of the first () and second () results of parallel measurements of the impurities in the same sample.

2. When checking the established norms of permissible differences of the two results of the analysis for taking the arithmetic mean of the two matched analyses.


(Changed edition, Rev. N 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 25086.

1.2. The systematic examination of the reproducibility of the analysis of samples according to GOST 18242.

(Added, Rev. N 2).

2. EQUIPMENT AND MATERIALS

Photovoltaic plant (quantometer) type MFS-8.

The type of generator UGE-4.

To register the radiation with the help of quantometer DFS-10M lines of arsenic (234,98 nm) and «internal standard» (background-228,3 nm) is used photomultipliers type FEU-5, which are mounted without mirrors. For lines of other elements and other «internal standards» (see table.3) use photomultipliers type FEU-4 and photocells f-1.

Electrodes of copper grade M-1 or from grade coal With a-3 in the form of bars with diameter 6−7 mm, sharpened to a hemisphere or truncated cone.

A device for grinding coal and copper electrodes, machine model CP-35.

Lathe for sharpening and analyze samples on the plane of the type of TV 16.

Standard samples, manufactured in accordance with GOST 8.315.

Allowed to use other equipment, equipment, materials and reagents, subject to obtaining the metrological characteristics are not worse than specified in this standard. Measuring instruments must be certified in accordance with GOST 8.326*.
______________________
* In the Russian Federation there are PR 50.2.009−94

Sec. 2. (Changed edition, Rev. N 2).

3. PREPARATION FOR ASSAY

Preparation of the analyzed samples and analysis must be the same type for each series of measurements. The sample should represent templet or a piece of arbitrary shape. The sample mass and should not differ by more than two times.

Sample preparation (or WITH) conducting a sweep of one of its faces on a plane with a file or cutting tool (the machine) without coolant and lubricant. During exposure of each spectrum, the stripped surface should be a flat pad with a diameter of not less than 10 mm without holes, scratches, cracks, and slag inclusions. Before exposure spectra for removing surface contamination of the analyzed samples and wipe WITH ethanol.

Sec. 3. (Changed edition, Rev. N 2).

4. ANALYSIS

The test sample or clamped in the lower clamp of the tripod and fed by coal (or copper) electrode so that the distance from ubeskrivelig plot to the edge of the sample was not less than the sparking spots (2−5 mm).

Between the ends of the electrodes are moved apart to (1,5±0,02) mm, light arc, AC, 3−8 power And or low voltage spark with a capacity of 40 microfarads, an inductance of 500 µh and the power of 2.5−3 A, or unipolar arc (with the inclusion of the sample as the anode of the arc) force 2.5 A powered by a generator UGE-4 from the mains (220±5) V.

Mode source control — phase. For excitation sources spectrum arc AC and low-voltage spark, the ignition phase is set equal to 90°, and for the unipolar arc — 125°. The width of the entrance slit of a DFS quantometer-10M is 0.02−0.07 mm. the baking Time of 10−15 s, the exposure time of not more than 90 C. Lighting the entrance slit of quantometer produced by a raster condenser. From each sample and receive two readings registered device.

The wavelengths of the analytical lines, the lines of «internal standards», the value of the mass fraction of elements and sources of the excitation spectrum are given in table.3.

Table 3

The wavelengths of the analytical lines, the lines of «internal standards»,
the ranges of detectable concentrations of the elements and sources
the excitation spectrum

Allowed the use of other analytical lines, the lines of «internal standards» sources of spectra excitation subject to obtaining the metrological characteristics are not worse than specified in this standard.

Signals recorded in accordance with the manual of the device.

Sec. 4. (Changed edition, Rev. N 2).

5. PROCESSING OF THE RESULTS

Calibration graphs constructed in the coordinates: and (or) .

The main method is the method of «three standards». Allowed the use of other methods of graphing, such as solid calibration curve method, standard method of control, etc.

The final result of the analysis taking the arithmetic mean of two parallel definitions, corresponding to the two counts registered device.

Permissible differences of two parallel definitions, and the two results of the analysis shall not exceed the values given in table.2.

Control of accuracy of analysis results is carried out according to GOST 25086 using the State branch standard samples or standard samples of enterprises.

Sec. 5. (Changed edition, Rev. N 2).