GOST 9716.3-79

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  ГОСТ 9716.3-79

GOST 9716.3−79 Alloy copper and zinc. Method of spectral analysis on the oxide samples with photographic registration of spectrum (with Change No. 1)

GOST 9716.3−79

Group B59

INTERSTATE STANDARD

ALLOYS COPPER-ZINC

Method of spectral analysis on the oxide samples
with photographic registration of spectrum

Copper-zinc alloys. Method of spectral analysis of oxide spesimens
with photographic registration of spectrum

AXTU 1709

Date of introduction 1981−01−01

INFORMATION DATA

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

DEVELOPERS

A. M. Rytikov, M. B. Taubkin, A. A. Nemodruk, M. P., Burmistrov, I. A. Vorobyev

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 26.12.89 N 5045

3. REPLACE GOST 9716.3−75

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. Limitation of actions taken by Protocol No. 5−94 of the Interstate Council for standardization, Metrology and certification (ICS 11−12−94)

6. The re-release (Oct 1998) with amendment No. 1, approved in July 1990 (IUS 11−90)


This standard applies to brass stamps LS59−1, L63, LO70−1, l96, L68 and L90 GOST 15527* and sets the method of spectral analysis on the oxide samples with photographic registration of spectrum.
______________
* On the territory of the Russian Federation GOST 15527−2004. — Note the manufacturer’s database.

The method is based on using as a test samples and standard samples (CO) oxide powders of brass, obtained by dissolving the metal in nitric acid followed by thermal decomposition of salts. Pressed into briquettes or powder samples WITH a graphite base is introduced into the arc DC. The spectrum produced by a spectrograph.

The method provides the possibility to analyze samples in any form.

The method allows to determine in brass iron, lead, antimony, Nickel, aluminum, tin, bismuth, silicon and arsenic in the range of mass fraction, indicated in the table.1.

Table 1

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

The interval defined by the mass fraction of elements can be extended both in smaller and in a big way through the use of the SOP and depending on the applied instruments and methods of analysis.

(Changed edition, Rev. N 1).

1. GENERAL REQUIREMENTS

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

(Changed edition, Rev. N 1).

2. APPARATUS, REAGENTS AND SOLUTIONS

The quartz spectrograph or diffraction medium, or large variance. Allowed the use of spectral apparatus with photoelectric registration of spectrum, if it provides the metrological characteristics are given in table.2.

Table 2

Notes:

1. When verifying compliance with established standards of permissible differences of the two results of parallel measurements for be 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 average of the two results of the analysis of the same sample obtained at different times.


Method of spectral analysis on the oxide samples is arbitration.

A constant current source to power the arc, providing a voltage of 200−400 V and currents up to 10 A.

Device for high-frequency ignition of the DC arc from the generator of any system (PS-39, DG, IG).

Microphotometer designed for measuring optical densities of spectral lines and background.

Oil press, hydraulic or any other, providing a pressure of 1.5−2 t

The mold of stainless steel (e.g., CVH) with a punch diameter of 6 mm; a height of 50−80 mm (Fig.1). The plunger and the inner surface of hardened cement matrix and then carefully sanded and brought to the surface.

Muffle furnace of any type with thermocouple, which allows to obtain and maintain temperatures up to 800 °C.

Cup platinum, porcelain or quartz varicellae for dissolution and evaporation of samples (dissolution, you can also use flasks or in the glasses heat resistant glass).

Damn.1. Kit for pressing powders

Kit for pressing powders

1 — lid (St 45); 2 — matrix (Article 3); 3 — the plug (bronze or u7); 4 — cover (Article 45);
5 — foot (u7); 6 — screw (St 35); 7 — bushing (bronze, steel, etc.)

Damn.1

Electrodes-foot graphite with a diameter of 8−10 mm. To place the briquettes on the electrodes they drill the recess with a diameter of 6 mm and a depth of 1.5−2 mm (Fig.2).

Damn.2. The location of the electrodes with the sample when shooting

The location of the electrodes with the sample when shooting

and — the location and size of the electrodes and of the briquette before the exposure; b — shot in the anode mode;
in shooting in cathode mode; 1 — graphite stand; 2 — briquette; 3 — melt;
4 — a front electrode

Damn.2

Coals spectral diameter 6−7 mm, grade C2 or C3.

Standard samples, manufactured in accordance with GOST 8.315.

The machine with a set of shaped cutters for sharpening protivoelektrodom and electrode supports.

Spectrographic plates type 1 or type 2 sensitivity 0,5−5 units., «Micro» sensitivity 10−60 units and plate type UFS.

Drying Cabinet.

The hotplate.

Analytical scale 200 g with weights of type ADV-200.

Mortar agate or from glass.

Boxy for storage.

Tweezers for gripping of briquettes.

Caps, glass or plastic to protect from dust sharpened electrodes.

Magnet type MVM 63.

Stopwatch on the other 25−1819.0021 TU 25−1894.003 or time relay.

Nitric acid according to GOST 4461, diluted 1:1 or 1:3.

The technical rectified ethyl alcohol according to GOST 18300.

Metol (para-methylaminophenol).

Hydroquinone (paradoxians) according to GOST 19627.

Sanitarily anhydrous sodium GOST 195.

The anhydrous sodium carbonate according to GOST 83.

Potassium bromide according to GOST 4160.

Chernovetskiy crystalline sodium (thiosulfate) according to GOST 244.

Acetic acid according to GOST 61.

Distilled water according to GOST 6709.

Developer for plates the spectral type 1, 2 and «Micro» is prepared by mixing equal volumes of solutions 1 and 2 before use.

Solution 1; prepared as follows: 2.5 g of metol 12 g of hydroquinone and 100 g of sodium semitecolo dissolved in 500−700 cmof water and add water to 1 DM.

Solution 2; is prepared as follows: 100 g of sodium carbonate and 7 g of potassium bromide dissolved in 500−700 cmof water and add water to 1 DM.

You can also use other contrasting working developers.

Developer for plates the spectral type UFS; prepared as follows: 2.2 g of metol, 8.8 grams of hydroquinone, 96 g semitecolo sodium, 48 g of sodium carbonate and 5 g of potassium bromide dissolved in 500−700 cmof water and add water to 1 DM.

Fixing solution; prepared as follows: 300 g of sodium thiosulfate, 25 g of sodium semitecolo and 8 cmof acetic acid are dissolved in 1 DMdistilled water.

The use of other measuring instruments with the metrological characteristics of equipment and technical characteristics are not worse, and reagents for quality not lower than the above.

Measuring instruments must be certified in accordance with GOST 8.326*.
______________
* On the territory of the Russian Federation there are PR 50.2.009−94. — Note the manufacturer’s database.

(Changed edition, Rev. N 1).

3. PREPARATION FOR ASSAY

3.1. Sample ofmagnesium and cleaned from surface contamination by etching in nitric acid, diluted 1:3, 5−10 C, then washed with water, ethyl alcohol and dried at 105 °C. an Average sample weight of not less than 3 g is placed in vipiteno Cup, poured nitric acid (1:1) at the rate of 10−15 cmof acid per 1 g of the metal is dissolved with moderate heating. The resulting solution was evaporated to dryness, a Cup of dry salt is placed in a muffle furnace, calcined at (700±20) °C for 15−20 min until the termination of allocation of oxides of nitrogen and the resulting oxides are ground in a mortar.

(Changed edition, Rev. N 1).

3.2. WITH turning chips after removing the contaminated surface layer on a lathe. Training FROM the analysis are as indicated in claim 3.1.

3.3. The obtained powders are selected from two sample mass (0,50±0,01) g and briquetted in a steel mold (Fig.1); prepared for shooting pellets stored in buksh.

Allowed to carry out the oxidation of the original sample and FROM the samples by melting in the arc of DC in an atmosphere of oxygen.

(Changed edition, Rev. N 1).

4. ANALYSIS

4.1. The mechanical part of the electrodes for removal of surface contaminants calcined in an arc of DC current for 20 s at 6−10 And including the electrode-stand as the anode of the arc. Briquettes samples and placed on a calcined graphite stand.

As a counter used spectral-clean coals.

The shape and size of the electrodes and their arrangement in the exposure time given on features.2.

4.2. To determine the mass fraction of lead, antimony, tin, bismuth, arsenic and graphite stand is placed on a preform of the analyzed image or include as the anode of the arc. When you turn on the current until melting of the briquette arc lights between the dummy electrode and the stand and only after the reflow part of the briquette the anode spot of the arc moves onto the formed melt of oxides. This transition is accelerating because after a few seconds of arc current is turned off and again turn it on until the melt has not yet had time to cool down. Getting exposure is considered after the transition of the anode spot of the arc on the briquettes. During the whole time of the exhibition it is necessary to adjust the initially established arc gap around the magnified image of the arc on the screen of the objective lens of the lighting system or with a special short throw projection lens.

Shooting conditions the spectrogram: the slot width of 0.010−0.015 mm; illumination of the slit by using a three-lens Achromat condenser; the diaphragm is in the middle of the condenser lens is 5 mm; the arc gap is 3 mm; rated current 6 to 8 A; the exposure time is 60−90 s.

The shortwave part of the spectrum photographed on the plates UPS, and wavelengths on the plates of type 1, 2 or «Micro».

4.3. To determine the mass fraction of lead in brass l96 and a mass fraction of iron, Nickel, aluminum and silicon in other brands of brass, formed goldcrests according to claim 4.2 is placed on svezhezakachannyh stand included as the cathode of the arc (Fig.2). Getting exposure counts after the transition of the cathode spot of the arc on the molten portion of the bead.

Shooting conditions the spectrogram: the width of the slit — 0,010−0,015 mm;

lighting cracks using the three-lens Achromat condenser; the diaphragm is in the middle of the condenser lens is 5 mm; the arc gap is 3 mm; rated current: 6 to 7 A; the exposure time is 30−40.

Spectra of the samples and photograph one of the plates has type 1 or type 2.

4.2, 4.3. (Changed edition, Rev. N 1).

4.4. In cases where the shooting conditions of the spectra are different from recommended (for example, the slit is illuminated by means of single-lens condenser, used a different power current, the other plate sensitivity, etc.), you should choose the conditions to select optimal interval the optical densities of the lines.

The exposure time is adjusted depending on the sensitivity of the used photographic plates, ensuring the normal optical density of the background of the continuous spectrum; otherwise, you have to build the characteristic curve. An increase in the density of the background due to the veils, lighting, etc. is not allowed because this decreases the sensitivity of the analysis.

4.5. A manifestation of photographic plates depending on the type carried out in the respective developer (see section 2) at a temperature of 18−20 °C. After washing the plates in tap water they are fixed in fixing solution, washed in running water and dried.

(Changed edition, Rev. N 1).

5. PROCESSING OF THE RESULTS

5.1. The optical densities of the analytical lines and «internal standards» in the spectrograms are measured with the aid of microphotometer.

The wavelengths of the analytical lines and «internal standards» (background) are shown in table.3.

Table 3

«Background 1» means the minimum value of the optical density of the background measured near the analytical line from the longer wavelengths;

«Background 2» background 259,715 nm. A maximum distance of 0.09 mm from the line of antimony 259,806 nm to shorter wavelengths;

«Background 3» — minimum value of optical density of the background measured near the line from the shorter wavelength;

«Background 4» means the minimum value of the optical density of the background measured near the line of tin 281,352 nm from the shorter wavelength;

«Background 5» — 289,60 nm. Second, implicitly defined maximum to shorter wavelengths from the line of bismuth 289,797 nm;

«Background 6» means the optical density of weak molecular lines 235,08 nm, which in the calculations is taken for the optical density of the background;

Background «7» means the minimum value of the optical density of the background measured near the line of lead 261,37 nm from the shorter wavelength.

Allowed the use of other analytical lines and «internal standards» subject to receipt of the metrological characteristics are not worse than specified in this standard.

The calibration graphs are built in coordinates

.

The primary method recommended to perform the analysis, is the method of «three standards». Allowed the use of other methods of graphing, for example, the method of solid calibration curve, method, control standard, etc.

Mass fraction of the designated contents of elements find the calibration schedule for the value found in the table of application calculated for the same spectrogram where .

The final result of the analysis be the arithmetic mean of results of two parallel measurements obtained on the same photographic plate.

Permissible differences of two parallel definitions, and two results of sample analysis shall not exceed the values given in table.2 (at confidence probability =0,95).

When finding the mass fraction of the element close to the rejection limit number of concurrent measurements is doubled, i.e., the photographing of the spectrum repeat on the second plate.

Control of accuracy of analysis results is carried out according to GOST 25086 using state, industry standard samples or standard samples of the enterprise.

(Changed edition, Rev. N 1).

APP (mandatory). TABLE of VALUES of lg ·I (l)/I (f) CORRESPONDING to the MEASURED VALUES of Delta S/"gamma»

APP
Mandatory

TABLE OF VALUES CORRESPONDING TO MEASURED VALUES

Explanations to the table

The table below serves for transmission of measured values to values . The table contains the results of the calculation

.

We denote the total intensity of the line with background through , the intensity of the background under the high line in the absence of a line through . Since , the ratio of line intensity to the background intensity is determined by the expression

. (a)

If the conditions of photographing the spectrum chosen so that the optical density of the line background and the background in the absence of the line are in the normal range,

, (b)

where ;  — contrast ratio.

Hence, using the expression (a), it is easy to

.

The table covers the most important to the practice of analytical work values from 0.05 to 1.9.

For its construction the table is divided into two parts: one part covering values from 0.05 to 0.99, and the part covering values from 1.00 to 1.99.

Consider the first part of the table (0,050,99). In the first left column of the table under the caption in bold printed values : 0,05; 0,06; 0,07…0,99.

The right of the sign in column headers in bold printed numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, depicting the third after the decimal point, the sign of the value . Having a certain value , for example =0,537, find the line of 0.53 corresponding to the first two decimal places, and column 7 to read respective value =0,388.

Similarly, for =0,143 0,14 in the row in column 3 to read a corresponding amount .

The second part of the table, covering values from 1.0 to 1.99 built in a similar way, with the difference that in the first left column the value is shown only with one decimal place, and the bold printed numbers 0, 1, 3…9 in the column headers represent the second after the decimal point, the sign of the value . So, having value =1,36, in the line of 1.3 in column 6 read =1,341.

For values smaller than had 0.301, the characteristic is negative, which is denoted by a minus sign over the characteristic (, …).

Since , this table can be used to find values corresponding to values , however they were not measured.

In routine analytical work it is permissible to omit the measurement taking a =1. This is a simplification of several curves calibration curve, if different from unity, but does not lead to significant errors in the analysis, since the same effect on the values obtained for WITH and samples.

Values corresponding to measured values