GOST 12349-83

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  ГОСТ 12349-83

GOST 12349−83 (ST SEV 1507−79) Steel alloyed and high alloy. Methods for determination of tungsten (Change No. 1)

GOST 12349−83
(ST CMEA 1507−79)

Group B39

STATE STANDARD OF THE USSR

STEEL ALLOYED AND HIGH-ALLOYED

Methods for determination of tungsten

Alloyed and high-alloyed steels.
Methods for determination of tungsten

AXTU 0809

Date of introduction 1983−06−01

APPROVED AND put INTO effect by the resolution Committee of USSR on standards on January 19, 1983 N 240

The validity period extended by decree of the state standard from 14.09.87 N 3513 to 01.01.98*
____________________
* Expiration removed by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification (I & C N 11, 1995). — Note the manufacturer’s database.

REPLACE GOST 12349−66*
____________________
* Probably a mistake of the original. Should read: REPLACE GOST 12349−66 but part of the overall guidance. — Note the manufacturer’s database.


REPRINT (December 1988) with amendment No. 1, approved in September 1987 (IUS 12−87).


This standard specifies methods for the determination of tungsten in alloy and high-alloy steels:

extraction-photometric — at a mass fraction of tungsten from 0.002 to 0.5%; photometric — at a mass fraction of tungsten of from 0.1 to 6.0%; photometric on the background of related elements — with the mass fraction of tungsten of from 0.3 to 18.0%;

gravity — if the mass fraction of tungsten from 3 to 20%.

The standard complies ST SEV 1507−79 in part by the photometric method when the mass fraction of tungsten of from 0.1 to 3% and the gravimetric method.

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 20560−81 with the following addition.

Laboratory scales for General purpose according to GOST 24104−80 the second class of accuracy with the greatest weighing limit of 200 g or any other scale corresponding to the specified GOST 24104−80 its tochnostyu characteristics.

(Changed edition, Rev. N 1).

2. EXTRACTION-PHOTOMETRIC METHOD (WHEN THE MASS FRACTION OF TUNGSTEN OF FROM 0.002 TO 0.5%)

2.1. The essence of the method

Extraction-photometric method based on formation of ion associate romanengo complex of tungsten (V) trimethylammonium (or cetylpyridinium), its extraction with chloroform and subsequent measurement of optical density of the extract at a wavelength of 400 nm.

The mass of tungsten is 10−100 ug per 25 cmof the extract. The optimum aqueous phase acidity 8 mol/lby hydrochloric acid.

The impact of iron and molybdenum is removed by introduction into the solution of the reducing agent: titanium trichloride and tin dichloride;

the influence of niobium — washing of the extract with potassium biperiden.

2.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter with all accessories.

Sulfuric acid GOST 4204−77, diluted 1:1.

Hydrochloric acid by the GOST 3118−77, diluted 1:1 and 2:1.

Nitric acid GOST 4461−77.

Orthophosphoric acid according to GOST 6552−80.

Tin dichloride 2-water on the other 6−09−5384−88*, a solution with a mass concentration of 100 g/DM. 10 g of tin dichloride dissolved in 100 cmof hydrochloric acid with mild heating.
________________
* The one referred to here and hereinafter, not shown. For additional information, please refer to the link. — Note the manufacturer’s database.


Titanium trichloride (solution) according to GOST 311−78: 5 cmof a solution of titanium trichloride mixed with 45 cmof hydrochloric acid, diluted 2:1, add 2 granules of zinc metal to enlightenment violet staining solution.

Or the prepared solution of titanium trichloride: 0.5 g of titanium metal according to GOST 19807−74 dissolved in 20 cmof hydrochloric acid. The solution was cooled and store in a flask made of dark glass with a glass stopper. Before use the solution was diluted in a ratio of 1:5 hydrochloric acid and add 2 granules of zinc metal to enlightenment violet staining solution.

Zinc, granulated.

Sodium hydroxide according to GOST 4328−77, a solution with a mass concentration of 440 g/DM.

Niobium metal according to GOST 16099−80 or GOST 16100−79.

The solution of niobium with a mass concentration of 0.001 g/cm: 0.25 g of niobium alloys with 2−3 g of potassium carbonate — sodium carbonate at 1000 °C. the crucible with the melt is placed in a glass, the melt is leached in water under heating. The solution was filtered in a volumetric flask with a capacity of 250 cm, was adjusted to the mark with water and mix.

Sodium volframovich according to GOST 18289−78.

Standard solutions of tungsten

Solution a: 1,7942 volframovich g of sodium is dissolved in 50 cmof water, add 50 cmof sodium hydroxide solution with the mass concentration of 440 g/DM, is poured into a measuring flask with a capacity of 1 DM, made up to the mark with water and mix.

Mass concentration of tungsten in solution A equal to 0.001 g/cm. The solution is stored in container made of polyethylene. The mass concentration of tungsten in the solution And checks according to claim 4.

Solution B: 10 cmsolution And placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

Mass concentration of tungsten in solution B is equal to 0.0001 g/cm.

Solution: 10 cmof solution B is placed in a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

Mass concentration of tungsten in solution is equal to 0,00001 g/cm.

Solutions B and C prepared before use and stored in a plastic container.

Chloroform technical according to GOST 20015−74.

Trimethylantimony bromide with molar concentration 0,01 mol/DM: 0,369 g of triethyltetramine dissolved in 100 cmof water during low heating or N-cetylpyridinium chloride with molar concentration 0,01 mol/DM: 0,339 g of cetylpyridinium dissolved in 100 cmof water without heating.

Hydroquinone (paradoxians) according to GOST 19627−74, solution in chloroform with a mass concentration of 0.65 g/DM: 0.65 g of hydroquinone are dissolved with stirring in 80 cmof ethanol, is added 920 cmof chloroform and stirred.

Rectified ethyl alcohol according to GOST 5962−67.

Acidic potassium fluoride (before).

Radio engineering carbonyl iron brand PS according to GOST 13610−79.

Potassium rodanistye according to GOST 4139−75, a solution with a mass concentration of 200 g/DM.

Potassium carbonate — sodium carbonate according to GOST 4332−76.

2.3. Analysis

2.3.1. Fractional the weight of steel (table. 1) is placed in a conical flask or beaker with a capacity of 250 cm, add 20 cmof hydrochloric acid of 1 cmof nitric acid and heated until complete dissolution of the sample. Add 10 cmof dilute sulfuric acid. 5 mmphosphoric acid and twice evaporated to sulphuric acid fumes, cooled, the salt is dissolved in 15−20 cmof water.

In the case of determining the content of tungsten in the range of mass fraction from 0.01 to 0.5% (table. 1), the solution transferred to a volumetric flask with a capacity of 100 cm, is diluted to the mark with water and mix. The solution is filtered through a dry filter of medium density.

Table 1

Aliquot part of the solution (table. 1) is placed in a beaker with a capacity of 100 or 250 cmand diluted with water to approximately 20 cm.

Then the solution aliquote part or in the whole sample solution was added 12 cmof hydrochloric acid (for acidity hydrochloric acid 8 mol/DM), 15 cmof a solution of tin dichloride and 10 cmof a solution of trichloride titanium. The solution was boiled for 5 min, cooled and transferred to a separatory funnel with a capacity of 100−200 cm, washing the walls of the Cup 10 cmof dilute hydrochloric acid (1:1). To the solution in separating funnel add 1cmof a solution of trimethylantimony bromide (or cetylpyridinium chloride) and 2 cmof a solution of potassium Rodenstock.

Extracted ion associate for 1 min, adding 25,0 cmof chloroform containing hydroquinone. The extract was filtered through a layer of cotton wool in the cuvette and measure the optical density of the extract on a spectrophotometer at a wavelength of 400 nm or photoelectrocolorimeter in a field of light transmission from 390 to 420 nm, using as a comparison solution of chloroform containing hydroquinone.

If a sample of steel contains niobium, the extract poured into a plastic vessel, add 1 g of potassium byflorida and shaken for 30 s. the Extract was filtered through cotton wool and measure the optical density as above.

Along with the analysis under the same conditions, conducting follow-up experience for contamination of reagents.

Depending on the mass fraction of tungsten is taken equal aliquote part of the sample and the reference experiment given in table. 1.

The value of optical density in the reference experiment is subtracted from the value of the optical density of the analyzed solution.

A lot of tungsten find for the calibration gra

fico.

2.3.2. To build a calibration curve in glasses with a capacity of 250 cmis placed a portion of the carbonyl iron 0.5 g and add 1,0; 2,0; 5,0; 8,0 cmmortar In tungsten at a mass fraction less than 0.01% or 1,0; 3,0; 5,0; 7,0; 10,0 cmof a solution of tungsten for the mass concentration of 0,01−0,5%, poured a solution of niobium, if present in the sample in an amount corresponding to its weight in the batches of samples and then do as described in section 2.3.1. Aliquota part of the solution in the construction of calibration curve of 10 cm.

A solution of comparison used chloroform containing hydroquinone.

Calibration curve built on the found values of optical densities and corresponding mass of tungsten.

2.4. Processing of the results

2.4.1. Mass fraction of tungsten () in percent is calculated by the formula

,

where is the mass of tungsten was found in the calibration schedule g;

 — the weight of the portion corresponding to aliquote part of the solution,

2.4.2. The absolute differences of the results of the parallel definitions should not exceed permissible values, specified in table. 2.

Table 2

Sec. 2. (Changed edition, Rev. N 1).

3. The PHOTOMETRIC METHOD (at a mass fraction of tungsten of from 0.1 to 6.0%)

3.1. The essence of the method

The method is based on the formation in the hydrochloric acid medium is colored a greenish-yellow complex compound of pentavalent tungsten romanistik with ammonia in the presence of a reducing agent titanium trichloride and measuring the optical density of the solution on the spectrophotometer at a wavelength of 400 nm or photoelectrocolorimeter in a field of light transmission from 390 to 420 nm. Iron, chromium and Nickel is pre-separated with sodium hydroxide.

The method is applicable to steels containing molybdenum and vanadium is not more than 10-fold amounts relative to the tungsten.

3.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77, diluted 2:1 and 1:100.

Nitric acid GOST 4461−77 or GOST 11125−84.

Sulfuric acid GOST 4204−77 or GOST 14262−78.

Orthophosphoric acid according to GOST 6552−80.

A mixture of sulphuric and phosphoric acids: 600 cmwater carefully poured, with stirring, 150 cmof sulphuric acid, and then 150 cmof phosphoric acid. Cool, dilute with water to 1 DMand stirred.

Double sulfate salt of oxide of iron and ammonium (salt Mora) according to GOST 4208−72.

Sodium hydroxide according to GOST 4328−77, solutions with mass concentration 40 g/l, 200 g/DM.

Ammonium radamisty according to GOST 27067−86, solutions with a mass concentration of 200 g/DM, 500 g/DM.

Titanium trichloride (solution) according to GOST 311−78: 5 cmof a solution of titanium trichloride mixed with 45 cmof hydrochloric acid, diluted (2:1), add 2 granules of zinc metal to enlightenment violet staining solution.

Or the prepared solution of titanium trichloride: 0.5 g of titanium metal according to GOST 19807−74 dissolved in 20 cmof hydrochloric acid. The solution was cooled and store in a flask made of dark glass with a glass stopper. Before use the solution was diluted in a ratio of 1: 5 hydrochloric acid and add 2 granules of zinc metal to enlightenment violet staining solution.

Zinc, granulated.

Sodium volframovich according to GOST 18289−78, standard solution. 1,7942 volframovich g of sodium are dissolved in 100 cmof sodium hydroxide solution with a mass concentration of 20 g/DM. The solution is poured into a measuring flask with a capacity of 1 DM, made up to the mark with sodium hydroxide solution with a mass concentration of 20 g/DM, mix.

Mass concentration of tungsten in solution is equal to 0.001 g/DM. The solution was stored in a plastic container.

Ammonium molybdate according to GOST 3765−78, a solution with a mass concentration of molybdenum of 0.001 g/DM: 1,8402 g of ammonium molybdate dissolved in water by heating, the solution was cooled, top up with water to 1 DM, mix.

Undeviatingly ammonium (meta) according to GOST 9336−75, a solution with a mass concentration of vanadium of 0.001 g/cm: 2,296 g of ammonium anadalucia dissolved by heating in 10 cmof sulphuric acid (1: 4), dilute with water to 1 DM,

mix.

3.1, 3.2. (Changed edition, Rev. N 1).

3.3. Analysis

3.3.1. To determine the mass fraction of tungsten of sample taking were:

1 year — when the mass fraction of tungsten of from 0.1 to 1.0%;

0.5 g — at a mass fraction of tungsten of 1.0 to 3.0%;

0.25 g — at a mass fraction of tungsten from 3.0 to 6.0%, is placed in a beaker with a capacity of 300 cm, 30 cm, pour thehydrochloric acid, 10 cmof nitric acid, cover the beaker watch glass and heated to dissolve sample.

After dissolution of the sample contents of the Cup is cooled, poured 30 cmof the mixture of acids and evaporated to release vapors of sulfuric acid. The side of the Cup carefully washed with water and again evaporate the solution to release of sulfuric acid vapor. After cooling the solution is carefully diluted with water to 100 cmand heated to dissolve the precipitate of salts. In the analysis of steels containing vanadium, to the solution was added 1−2 g of salt Mora. To the obtained solution poured 90 cmof 20% aqueous solution of sodium hydroxide, the contents of the beaker transferred to a volumetric flask with a capacity of 250 cm, cooled, made up to the mark with water and mix. After 20−30 min of the solution was filtered through two dry filter «white ribbon». The first portion of the filtrate discarded. In a volumetric flask with a capacity of 100 cmis placed aliquot part of the obtained filtrate, equal to 20 cm(when the mass fraction of tungsten of from 0.1 to 0.5%) and 10 cm(when the mass fraction of tungsten of more than 0.5 to 6.0%), flow 15 cm4% sodium hydroxide solution, 2 cmof a 50% strength solution of ammonium Rodenstock, 45 cmof hydrochloric acid (2:1), stirred and cooled to 14−17°C. the contents of the flasks add 12−15 drops of solution of titanium trichloride in portions of 4−5 drops thoroughly mix the solution after each addition of reagent. In the analysis of steels containing molybdenum, a solution of titanium trichloride is added in portions of 4−5 drops of 0.5−1 min to the disappearance of the color complex compound of molybdenum with thiocyanate-ion and add 5 drops in excess. The flask with the solution left for 10 min until the formation of a stable yellow-green color, then topped up to the mark solution of hydrochloric acid (2: 1), stirred and after 10 minutes measure the optical density of the solution on the spectrophotometer at a wavelength of 400 nm or photoelectrocolorimeter in a field of light transmission from 390 to 420 nm in a cuvette with a layer thickness of 50 mm. as a solution comparison solution is used in the reference experiment.

After subtracting the value of optical density of the solution in the reference experiment from the value of the optical density of the sample solution find the mass of tungsten in the calibration g

Rafik.

3.3.2. Building a graduated schedule for the mass fraction of tungsten of from 0.1 to 0.5%

Six glasses with a capacity of 300 cm, each is placed 1 g of the carbonyl (electrolytic) iron or low carbon steel containing no tungsten. In five glasses poured successively 1; 2; 3; 4; 5 cmstandard solution tungsten. In the analysis of steels containing molybdenum and vanadium, in all six of the cups add their solution with a mass concentration of molybdenum or vanadium 0,001 g/cmin an amount corresponding to the mass fraction in the analyzed sample.

Then poured on 30 cmof hydrochloric acid, and 10 cmof nitric acid, cover the glasses with watch glass and heated to dissolve sample. The contents of the beakers cooled, poured 30 cmof the mixture of acids and evaporated to release vapors of sulfuric acid. The walls of the cups carefully washed with water and evaporated again solutions to release vapor of sulfuric acid. After cooling, the solutions were carefully diluted with water to 100 cmand heated to dissolve the precipitate of salts and further in 3.3.1.

As a solution comparison, using a solution of carbonyl (electrolytic) iron without the addition of a standard solution tungsten (weight in the sixth Cup)

.

3.3.3. Construction of calibration curve for the mass fraction of tungsten of from 1 to 3%

Seven glasses of a capacity of 300 cmeach placed 0.5 g carbonyl (electrolytic) iron or low carbon steel containing no tungsten. Six glasses poured consistently 5; 7; 9; 11; 13; 15 cmstandard solution tungsten. Then pour seven cups 30 cmof the mixture of acids and then do as described in section 3.3.1.

On the found values of optical density of the solutions and their corresponding masses of tungsten to build a calibration curve.

3.3.1−3.3.3. (Changed edition, Rev. N 1).

3.4. Processing of the results

3.4.1. Mass fraction of tungsten () is calculated according to clause 2.4.1.

3.4.2. Allowable absolute differences must not exceed the values given in table. 2 and 4.

3.4.1, 3.4.2. (Changed edition, Rev. N 1).

3A. The PHOTOMETRIC METHOD (at a mass fraction of tungsten from 0.3 to 18%)

3A.1. The essence of the method

The method is based on the formation of greenish-yellow color complex compounds of pentavalent tungsten with thiocyanate ions in the presence of reducing agents — dichloride of tin and trivalent titanium in the hydrochloric acid solution with molar concentration of 4−6 mol/DMand subsequent measurement of optical density at a wavelength of 400−410 nm. Tungsten to determine the background of related items.

The influence of molybdenum and vanadium kompensiruet introducing them into the solution of calibration curve in the form of differential photometry — introduction them in a solution of comparison.

3A.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter with all accessories.

Hydrochloric acid by the GOST 3118−77, diluted 2: 1.

Nitric acid GOST 4461−77.

Sulfuric acid GOST 4204−77, diluted 1:1, 1:9.

Sodium hydroxide according to GOST 4328−77, solutions with a mass concentration of 200 g/l; 40 g/DM; 440 g/DM.

Potassium-sodium vinocity 4-water according to GOST 5845−79 (Sagatova salt) solution with a mass concentration of 250 g/DM.

Tin dichloride 2-water on the other 6−09−5384−88, a solution with a mass concentration of 250 g/l250 g of tin dichloride dissolved in 200 cmof hydrochloric acid, diluted to 1 DMwith water, mix. The solution was filtered and add 2−3 granules of tin metal.

Tin granulated GOST 860−75.

Ammonium radamisty according to GOST 27067−86, a solution with a mass concentration of 500 g/DM, freshly prepared.

Titanium trichloride according to GOST 311−78, a solution of 1 part of titanium trichloride solution is diluted with 75 parts of dilute sulfuric acid 1: 9. The solution is prepared before use.

Radio engineering carbonyl iron brand PS according to GOST 13610−79.

Sodium volframovich 2-water according to GOST 18289−78.

Standard tungsten solution with a mass concentration of 0.001 g/cmprepared according to paragraph 3.2.

Ammonium molybdate according to GOST 3765−78, a solution with a mass concentration of molybdenum 0.001 g/cm: 1.84 g ammonium molybdate was placed in a beaker and dissolved in water when heated. After cooling, the solution is transferred to a volumetric flask with a capacity of 1 DM, made up to the mark with water and mix.

Ammonium undeviatingly meta GOST 9336−75, a solution with a mass concentration of vanadium of 0.001 g/cm: 2.3 g ammonium anadalucia dissolved in 50 cmof water, add 150 cmof nitric acid, the solution was cooled, transferred to a volumetric flask with a capacity of 1 DMand stirred.

3A.3. Analysis

3A.3.1. Option spectrophotometry when the mass fraction of tungsten of from 0.3 to 10%

Fractional the weight of steel (table. 2A) is placed in a beaker, add 30 cmof a mixture of hydrochloric and nitric acids in the ratio 3:1 and boiled until complete dissolution of the sample, then add 20 cmdiluted 1:1 sulphuric acid and evaporated to fumes of sulfuric acid. After cooling the salt is dissolved in 50 cmof water when heated. The cooled solution was added a solution of sodium hydroxide (200 g/DM) to the precipitation of iron hydroxide and 10 cmin excess, is added 20 cmof a solution of potassium-sodium Vinokurova and 25 cmof dilute sulfuric acid 1:1. The solution was mixed thoroughly after adding each reagent. The cooled solution is transferred to a volumetric flask with a capacity of 250 cm, is diluted to the mark with water and mix.

Aliquot part of the solution (table. 2A) is placed in a volumetric flask with a capacity of 100 cm, add 2 cmof a solution of dichloride of tin, after 2 min add 15 cmof sodium hydroxide solution (40 g/DM), 45 cmdiluted 2:1 hydrochloric acid, 2cmof a solution of ammonium Rodenstock and 2 cmof solution trichloride titanium, after 5 min, dilute to the mark with water and mix.

Table 2A

Optical density of the solution is measured on a photoelectrocolorimeter in a region of wavelengths 390−420 nm, or spectrophotometer at a wavelength of 400−410 nm. As a solution comparison, using aliquot part of the solution, containing all reagents except Rodenstock ammonium trichloride and titanium.

At the same time under the same conditions conduct control experience for contamination of reagents. The value of optical density in the reference experiment is subtracted from the value of the optical density of the analyzed solution.

To build a calibration curve in the glasses is placed a suspension of carbonyl iron, solutions of vanadium and molybdenum in an amount corresponding to their mass in the sample the test sample, a standard solution of tungsten in increasing amounts so that the weight of the tungsten in the test sample was in the middle of the chart, go 30 cmof a mixture of hydrochloric and nitric acids in the ratio 3: 1 and further on p. 3A.3.1.

3A.3.2. Version of the differential photometry with the mass fraction of tungsten from 10 to 18%

Weighed 0.5 g of steel placed in a beaker, add 30 cmof a mixture of hydrochloric and nitric acids in the ratio 3: 1 and further on p. For.3.1.

Aliquot part of the solution is 5 cmcontaining 1100−2000 g of tungsten was placed in a volumetric flask with a capacity of 100 cm, add 2 cmof a solution of tin dichloride, in 2 min 15 cmof sodium hydroxide solution (40 g/DM), 45 cmdiluted 2: 1 hydrochloric acid, 2cmof a solution of ammonium Rodenstock and 2 cmof solution trichloride titanium, after 5 min, dilute to the mark with water and mix.

Optical density of the solution measured on a spectrophotometer or photoelectrocolorimeter in a cuvette with a layer thickness of 10−30 mm in the area of waves 390−420 nm relative to solution comparison.

For solution comparison in a glass put a suspension of carbonyl iron, solutions of vanadium and molybdenum in amounts corresponding to their mass in the sample the test sample, 40−50 cmstandard solution of tungsten with a mass concentration of 0.001 g/cm, add 30 cmof a mixture of hydrochloric and nitric acids in the ratio 3: 1, and further receives, as described in paragraph For.3.1.

To build a calibration curve to aliquote part of the solution compare add standard solution of tungsten with a mass concentration of 0.0001 g/cmin increasing amounts so that the weight of the tungsten in the test sample was in the middle of the chart, add 2cmof a solution of tin dichloride, in 2 min 15 cmof sodium hydroxide solution (40 g/DM), 45 cmdiluted 2: 1 hydrochloric acid, 2cmof a solution of ammonium Rodenstock and 2 cmof titanium trichloride. After 5 min, dilute to the mark with water and mix. Optical density of the solution is measured after 10 minutes relative to the comparison solution.

Calibration curve built on the found values of optical density and corresponding values of the mass of tungsten in the standard solutions added to aliquote part of the solution comparison.

3A.4. Processing of the results

3A.4.1. Mass fraction of tungsten () percent for the range of determinable content of from 0.3 to 10.0% calculated, as specified in clause 2.4.1.

Mass fraction of tungsten () option differential spectrophotometry is calculated by the formula

,

where  — the sum of the mass of tungsten was found in the calibration schedule, and weight entered in the reference solution, g;

 — the weight of the portion corresponding to aliquote part of the solution,

3A.4.2. The absolute differences of the results of the parallel definitions should not exceed permissible values, specified in table. 2 and 2B.

Table 2B

Sec. 3A. (Added, Rev. N 1).

4. GRAVIMETRIC METHOD

4.1. The essence of the method

The method is based on hydrolytic sedimentation of tungsten acid in the presence of gelatin and gravimetric determination of tungsten trioxide with the introduction of amendments to the content of tungsten in the filtrate from tungsten acid determined by photometric method, and corrected for the impurities: Fe,O; TiO; SGO; Moo; VO; TaONbOin trioxide WOL

FRAM.

4.2. Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter with accessories.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77 diluted 1:1, 1:10 and a solution with a molar concentration of 3 mol/DM.

Nitric acid GOST 4461−77 or GOST 11125−84 diluted 1:1.

Sulfuric acid GOST 4204−77 or GOST 14262−78 diluted 1:1, 1: 3, 1: 5 and 1:9.

Hydrofluoric acid according to GOST 10484−78, a solution with a mass concentration of 400 g/DM.

Orthophosphoric acid according to GOST 6552−80, diluted 1: 1.

Ammonia water according to GOST 3760−79 diluted 1:3 and 1:1.

Gelatin food according to GOST 11293−78, a solution of 5 g/DM.

Sodium carbonate according to GOST 83−79, a solution with a mass concentration of 5 g/DM.

Acidic potassium sulfate according to GOST 4223−75.

Iron carbonyl.

Standard iron solution

Solution a: 0,2500 g of iron is dissolved with moderate heating in 10 cmof hydrochloric acid. After cooling, transfer the solution into a volumetric flask with a capacity of 500 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.0005 g of iron.

Solution B: 25,0 cmsolution And transferred to a volumetric flask with a capacity of 500 cm, is diluted to the mark with water and mix.

1 cmof the solution contains 0,000025 g of iron.

Hydroxylamine hydrochloride according to GOST 5456−79, a solution with a mass concentration of 10 g/DM.

1,10-fenantrolin, a solution with a mass concentration of 1.5 g/DM.

Acetic acid GOST 61−75.

Sodium acetate 3-water according to GOST 199−78, a solution of 272 g of sodium acetate dissolved in 500 cmof water, add 240 cmof acetic acid, dilute with water to 1000 cmand, if necessary, filtered.

Reaction mixture: 1 part of a solution of hydrochloric acid hydroxylamine, 1 part of a solution of 1,10-phenanthroline mixed with 3 parts of a solution of sodium acetate; cook before eating.

Ascorbic acid, a solution with a mass concentration of 50 g/DM.

Diantipyrylmethane, a solution with a mass concentration of 30 g/DM.

Titan according to GOST 19807−74.

Standard solutions of titanium

Solution a: 0,100 g of the titanium is dissolved by heating in 100 cmof solution of sulfuric acid (1: 5). After reconstitution, the solution is oxidized by adding dropwise nitric acid and a short boiling removes oxides of nitrogen. After cooling, the solution is transferred into a measuring flask with volume capacity of 1000 cm, made up to the mark with sulfuric acid solution (1:5) and stirred.

1 cmof the solution contains 0.0001 g of titanium.

Solution B: 10.0 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with sulfuric acid solution (1:5) and stirred.

1 cmof the solution contains 0.0001 g of titanium.

Silver nitrate according to GOST 1277−75, a solution with a mass concentration of 5 g/DM.

Ammonium neccersarily according to GOST 20478−75, a solution with a mass concentration of 100 g/DMfreshly prepared.

Ethyl alcohol according to GOST 5962−67.

Diphenylcarbazide according to GOST 5859−78, a solution with a mass concentration of 1 g/lin ethanol.

Potassium dichromate according to GOST 4220−75.

Standard solution of chromium: 0,0566 g of potassium dichromate, previously dried at 150 °C, dissolved in water, the solution is transferred into a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.

1 cmof the solution contains 0,00002 g of chromium.

Potassium-sodium vinocity according to GOST 5845−79.

Potassium rodanistye, with a mass concentration of 100 g/DMaccording to GOST 4139−75.

Tin metal granules according to GOST 860−75.

Tin dichloride 2-water according to GOST 36−78, a solution with a mass concentration of 100 g/l: 100 g of tin chloride dissolved in 100 cmof hydrochloric acid and the solution diluted with water to 1000 cm. To the thus prepared solution add a few granules of metallic tin.

Molybdenum metal, high purity according to normative-technical documentation.

Standard solutions of molybdenum.

Solution a: 0,500 g of molybdenum are dissolved in 10 cmof sulfuric acid solution (1:1) and 10 cmof nitric acid. The solution is evaporated to release the white fumes of sulfuric acid, after cooling, transferred into a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.

1 cmof the solution contains 0.0005 g of molybdenum.

Solution B: 10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, is diluted to the mark with water and mix.

1 cmof the solution contains of 0.00005 g of molybdenum.

Sodium volframovich according to GOST 18289−78, a solution with a mass concentration of 160 g/DM.

Of vanadium pentoxide.

Standard solutions of vanadium.

Solution a: 0,4462 g of vanadium pentoxide dissolved in 50 cmof sulfuric acid solution (1:9) and 5 cmof nitric acid. The solution is evaporated to release the white fumes of sulfuric acid, after cooling, transferred to a volumetric flask with a capacity of 500 cm, made up to the mark with sulfuric acid solution (1:9) and stirred.

1 cmof the solution contains 0.0005 g of vanadium.

Solution B: 10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with sulfuric acid solution (1:9) and stirred.

1 cmof the solution contains of 0.00005 g of vanadium.

Potassium carbonate according to GOST 4221−76.

Ammonium nitrate according to GOST 22867−77, a solution with a mass concentration of 10 g/DM, with the addition of 1 cmof ammonia at 1000 cmof solution.

Phenolphthalein on the other 6−09−5360−87, a solution with a mass concentration of 1 g/lin ethanol.

4.1, 4.2. (Changed edition, Rev. N 1).

4.3. Analysis

4.3.1. The weight of steel depending on the mass fraction of tungsten is determined by the table. 3.

Table 3

The sample is placed in a beaker with a capacity of 600 cm, cover with a watch glass and dissolved in 50−70 cmof hydrochloric acid (1:1) at a temperature close to boiling point (90°C), until the termination of allocation of bubbles of hydrogen. In the case of sparingly soluble steel during dissolution of the sample add a solution of hydrochloric acid (1:1), pouring it in a glass to the original volume. After decomposition of the sample heating was stopped and the solution is oxidized by adding dropwise a solution of nitric acid until the termination of allocation of oxides of nitrogen; then add an excess of about 1 cmof a solution of nitric acid. The solution is heated to 60−80°C, periodically stirring it to release the yellow precipitate tungsten acid. The solution was then diluted with hot water to a volume of about 150 cm, add a 10 cmgelatin solution, small amounts of paper pulp and heat the solution, stirring occasionally, to a temperature of about 90 °C for 30 min. When the mass fraction of molybdenum in excess of 1% solution allowed to stand for 36 h for complete precipitation of tungsten acid.

The solution above the sediment was filtered through the filter medium density containing a small amount of paper pulp, the precipitate tungsten acid in a glass first washed 2−3 times by decantation, then washed the filter cake 10−12 times with water.

The filter with the precipitate is transferred in a weighed platinum crucible. The remainder tungsten acid from the walls of glass rubbed with a piece of filter paper saturated with a solution of ammonia (1: 3), attached to the residue in the crucible, and burn the residue in the crucible is calcined at (800±50)°C. after cooling, add 1−2 drops of sulfuric acid (1:1) and 1 to 3 cmof a solution of hydrofluoric acid, evaporated to dryness, calcined at (800±50)°C to constant weight after cooling in a desiccator weighed precipitate of tungsten trioxide.

The filtrate is evaporated to small volume and then do as described in section 3.3. In the analysis of steels containing more than 1% molybdenum and vanadium for additional tungsten, using extraction-photometric method according to paragraph 2.3. Found a lot of tungsten in grams converted to the trioxide of tungsten, 1,2619 multiplying by and adding to the result of the gravimetric determination of tungsten trioxide.

(Changed edition, Rev. N 1).

4.3.2. Determination of impurities of FeO, CRO, Moo, VO, TiO, NbOand TaOin the precipitate of tungsten trioxide is carried out as follows

time.

4.3.2.1. In the analysis of steels containing no niobium and tantalum, tungsten trioxide in a platinum crucible, fuse with 5 g of anhydrous sodium carbonate. The smelt is leached 100 cmof hot water and solution and the precipitate was filtered through a filter with a medium density paper stock. The residue on the filter is washed first 5−8 times with sodium carbonate solution, and then 2−3 times with water. The precipitate on the filter used to determine the FeOand TiO, in the filtrate determine the SGO, Moo, and VO.

For determination of FeOand TiOfilter with the precipitate is burned in a platinum crucible and the residue fused with 2 g of acidic potassium sulfate. The smelt is dissolved in 20 cmof a hydrochloric acid solution (1:1), the solution transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

Determination of FeO: aliquot part by volume of 10 to 20 cmcore solution is transferred to a volumetric flask with a capacity of 100 cm, is diluted with water to a volume of about 50 cm, neutralized with ammonia solution (1:1) to phenolphthalein and then acidified by 2 cmof hydrochloric acid (1: 1). Add 25 cmof the reaction mixture, made up to the mark with water and mix. After 30 min, measure the optical density of the solution at a wavelength of 510 nm. Solution comparison is water. Weight of iron in the sample solution in grams find the calibration schedule, after subtracting the value of optical density of the solution in the reference experiment from the value of the optical density of the sample solution.

To plot in six of the seven volumetric flasks with a capacity of 100 cmadd 1,0; 2,0; 4,0; 8,0; 12,0 and 16,0 cmstandard solution B. iron In all flasks add water up to 50 cmand then do the above method.

The weight of FeOin grams is calculated by the formula

,

where is the mass of iron in the sample solution, found by calibration schedule, after subtracting the value of optical density of the solution in the reference experiment from the value of the optical density of the sample solution, g;

 — the weight of the portion corresponding to the selected part of the solution, g;

the weight of steel, g;

1,430 — the ratio of Fe to FeO.

Definition of TiO: in two volumetric flasks with a capacity of 50 cm andstand 20 cmbasic solution, add 5 cmof a solution of ascorbic acid and after 3 min in the 10 cmof a 3 M solution of hydrochloric acid. Then to one of the flasks was added 10 cmof the solution diantipyrylmethane. After adding each of the solutions of the contents of the tubes mixed, made up to the mark with water and mixed again. After 60 min, measure the optical density of colored solution at a wavelength of 395 nm. Solution comparison is part of the basic solution with the addition of all reagents, except diantipyrylmethane. The mass of titanium in the sample solution in grams find the calibration schedule, after subtracting the value of optical density of the solution in the reference experiment from the value of the optical density of the sample solution.

To plot in six of the seven volumetric flasks with a capacity of 50 cmadd 1,0; 2,0; 4,0; 8,0; 12,0 and 16,0 cmstandard solution titanium B. In all flasks add water up to 20 cm, 5 cmsolution of ascorbic acid and then do the above method.

TiO massin grams is calculated by the formula

,

where is the mass of titanium in the sample solution, found by calibration schedule, after subtracting the value of optical density of the solution in the reference experiment from the value of the optical density of the sample solution, g;

 — the weight of the portion corresponding to the selected part of the solution, g;

the weight of steel, g;

1,668 — the ratio of Ti to TiO.

To determine SG,O, Moo, and VOto the filtrate obtained after separation of iron and titanium, is added a solution of hydrochloric acid (1:1) until acidic reaction (control indicator paper) and boil for approx 20 min, then diluted with a solution of 30−40 cmof hot water, boil for another 5 min and filtered through a filter of medium density. Filter the precipitate tungsten acid-washed with hydrochloric acid (1: 10). To the filtrate add 6 cmof sulfuric acid solution (1: 1) and evaporated to release the white fumes of sulfuric acid. After cooling, add 50 cmof water, the solution was filtered through a filter of medium density in a volumetric flask with a capacity of 250 cm, cooled, adjusted to the mark with water and mix. From thus obtained primary solution taken aliquote part to determine SGO, Moo, and VO.

The definition of SGO: from the core of the solution is transferred aliquot part of 25 cmin a glass with a capacity of 100 cm, add 3 cmof a solution of silver nitrate, 10 cmnaternicola solution of ammonia, heated to boiling and boil until the destruction of excess ammonium naternicola. After cooling, transfer the solution into a volumetric flask with a capacity of 50 cm, add 2 cmof solution diphenylcarbazide, adjusted to the mark with water and mix. After 5 min measure the optical density of the solution at a wavelength of 520 nm. Solution comparison is water. The mass of chromium in the sample solution in grams find the calibration schedule, after subtracting the value of optical density of the solution in the reference experiment from the value of the optical density of the sample solution. To plot in six of the seven volumetric flasks with a capacity of 50 cmadd 0,5; 1,0; 2,0; 3,0; 5,0 and 7,0 cmstandard solution of chromium. To all flasks add 1 cmof sulfuric acid solution (1:3), dilute with water to 20 cmand then do the above method.

The SG mass ofOin grams is calculated by the formula

,

where is the mass of chromium in the sample solution, found by calibration schedule, after subtracting the value of optical density of the solution in the reference experiment from the value of the optical density of the sample solution, g;

 — the weight of the portion corresponding to the selected part of the solution, g;

the weight of steel, g;

1,4614 — the conversion factor to SG SGO.

Definition of Moofrom the basic solution are transferred aliquot part of the 25 cmof the solution in a volumetric flask with a capacity of 50 cm, add 2 g of potassium Vinokurova-sodium, 10 cmpotassium Rodenstock solution and stirred. Then add 10 cmof a solution of chloride of tin, the contents of the flask brought to the mark with water and mix. After 5 min measure the optical density of the solution at a wavelength of 490 nm. Solution comparison is water. The mass of molybdenum in the sample solution in grams find the calibration schedule, after subtracting the value of optical density of the solution in the reference experiment from the value of the optical density of the sample solution. To plot in six of the seven volumetric flasks with a capacity of 50 cmadd 0,5; 1,0; 2,0; 3,0; 5,0 and 7,0 cmstandard solution molybdenum B. In all flasks add water up to 25 cmand then do the above method.

A lot of Mooin grams is calculated by the formula

,

where is the mass of molybdenum in the sample solution, found by calibration schedule, after subtracting the value of optical density of the solution in the reference experiment from the value of the optical density of the sample solution, g;

 — the weight of the portion of the sample corresponding to the selected part of the solution, g;

the weight of steel, g;

1,500 — conversion factor from Mo to Moo.

The definition of VO: from the core of the solution is transferred aliquot part of 75 cmin a beaker with a capacity of 200 cm, add 5 cmof phosphoric acid, solution, 2 cmof mortar volframovich of sodium and heated to boiling. After cooling, transfer the solution into a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix. Measure the optical density of the solution at a wavelength of 365 nm. Solution comparison is water. A lot of vanadium in the sample solution in grams find the calibration schedule, after subtracting the value of optical density of the solution in the reference experiment from the value of the optical density of the sample solution.

To plot in six of the seven glasses with a capacity of 200 cmadd 0,5; 1,0; 2,0; 3,0; 5,0 and 7,0 cmstandard solution of vanadium B. In all the cups add water to a volume of 75 cm, 5 cmsolution of phosphoric acid and then do the above method.

V the mass ofOin grams is calculated by the formula

,

where is the mass of the vanadium in the sample solution, found by calibration schedule, after subtracting the value of optical density of the solution in the reference experiment from the value of the optical density of the sample solution, g;

 — the weight of the portion of the sample corresponding to the selected part of the solution, g;

the weight of steel, g;

1,785 — conversion factor V VO.

(Changed edition, Rev. N 1).

4.3.2.2. In the analysis of steels containing niobium and tantalum, tungsten trioxide is fused in a platinum crucible with 5 g of anhydrous potassium carbonate. The smelt is leached 100 cmof hot water and solution and the precipitate was filtered through a filter with a medium density paper stock, collecting the filtrate in a volumetric flask with a capacity of 250 cm. The filter residue is washed with potassium carbonate solution and then use it to determine the FeOand TiOaccording to claim 4.3.2.1. The filtrate in a volumetric flask top up to the mark with water, mixed and used to determine the NbO, TaO, CRO, Moo, and VO.

For determination of NbOand TaOof the filtrate is transferred aliquot part 100 cmin a beaker with a capacity of 400 cm. Acidified with nitric acid to acid reaction (control indicator paper), boiled for a short time and neutralized with ammonia. Then precipitated niobium and tantalum by adding 15 cmof ammonia solution (1:3), again not for long boil and the solution and the precipitate was allowed to stand for 30 min at a temperature of about 80 °C. the Precipitate was filtered off on a medium density filter and washed several times with ammonium nitrate solution. The filter with the precipitate is transferred in a weighed platinum crucible, burned, calcined and after cooling weighed NbO+ TaO.

Weight of NbO+ TaOin grams is calculated by the formula

,

where  — weight of NbO+ TaOin the analyzed part of the solution, g;

 — weight of NbO+ TaOin a control experiment, g;

 — the weight of the portion corresponding to the selected part of the solution, g;

the weight of steel,

To determine SG,O, Moo, and VOfrom the filtrate in a volumetric flask take aliquot part 100 cm, and the analysis is carried out for

p. 4.3.2.1.

4.4. Processing of the results

4.4.1. Mass fraction of tungsten () in percent is calculated by the formula

,

where is the mass of tungsten trioxide in the sample solution, g;

 — the mass of tungsten trioxide in solution in the reference experiment, g;

 — the mass of tungsten trioxide, as determined by the photometric method in the filtrate after separation of tungsten acid, g;

 — mass of impurities (FeO+ TiO+ NbO+ TaO+ SGO+ Moo+ VO), g;

the weight of steel, g;

0,7931 — the ratio of tungsten trioxide n

and tungsten.

4.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table. 2B and 4.

Table 4

(Changed edition, Rev. N 1).