GOST 11739.20-99

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  ГОСТ 11739.20-99

GOST 11739.20−99 Alloys aluminum casting and wrought. Method of determining titanium

GOST 11739.20−99

Group B59

INTERSTATE STANDARD

ALLOYS ALUMINIUM CAST AND WROUGHT

Method of determining titanium

Aluminium casting and wrought alloys. Method for determination of titanium

ISS 77.120.10
AXTU 1709

Date of introduction 2000−09−01

Preface

1 DEVELOPED by JSC «Russian Institute of light alloys» (JSC VILS), the Interstate technical Committee for standardization MTK 297 «Materials and semi-finished products of light alloys"

INTRODUCED by Gosstandart of Russia

2 ADOPTED by the Interstate Council for standardization, Metrology and certification (Protocol No. 16−99 dated 8 October 1999)

The adoption voted:

3 Resolution of the State Committee of the Russian Federation for standardization and Metrology dated February 18, 2000 N 41-St inter-state standard GOST 11739.20−99 introduced directly as state standard of the Russian Federation from September 1, 2000

4 REPLACE GOST 11739.20−82

1 Scope

This standard sets the photometric method for the determination of titanium in aluminium cast and wrought alloys with the mass fraction of titanium from 0.003% to 0.4%.

2 Normative references

The present standard features references to the following standards:

GOST 3118−77 hydrochloric Acid. Specifications

GOST 4038−79 Nickel (II) chloride 6-water. Specifications

GOST 4165−78 Copper (II) sulfate 5-water. Specifications

GOST 4204−77 sulfuric Acid. Specifications

GOST 4461−77 nitric Acid. Specifications

GOST 10484−78 hydrofluoric Acid. Specifications

GOST 10929−76 Hydrogen peroxide. Specifications

GOST 11069−74 Aluminium primary. Stamps*

GOST 17746−96 spongy Titanium. Specifications

GOST 25086−87 non-ferrous metals and their alloys. General requirements for methods of analysis
_________________
* On the territory of the Russian GOST 11069−2001, here and hereafter. — Note the manufacturer’s database.

3 General requirements

3.1 General requirements for methods of analysis GOST 25086 with the Supplement.

3.1.1 the result of the analysis be the arithmetic mean of results of two parallel measurements.

4 the essence of the method

The method is based on dissolving the samples in hydrochloric acid with addition of hydrogen peroxide, elimination of the influence of iron (III) and vanadium (V) recovery of ascorbic acid in the presence of copper sulphate (II), the formation in solution of hydrochloric acid 3 mol/DMyellow complex compound of titanium with diantipyrylmethane and measuring the optical density of the solution at a wavelength of 400 nm.

5 Apparatus, reagents and solutions

Spectrophotometer or photoelectrocolorimeter.

Oven muffle.

Hydrochloric acid according to GOST 3118 density of 1.19 g/cm, mortar is 2:1, 1:1 and 1:99.

Sulfuric acid according to GOST 4204 density 1.84 g/cmand a solution of 1:5, 1 mol/land 0.5 mol/DM.

Nitric acid according to GOST 4461 density of 1,35−1,40 g/cm.

Hydrogen peroxide according to GOST 10929.

Hydrofluoric acid according to GOST 10484.

Copper (II) sulfate 5-water according to GOST 4165, solution 50 g/l(calculated as anhydrous copper sulphate): 7.8 g of 5-water copper sulfate is dissolved in water, poured water to a volume of 100 cmand mixed.

Ascorbic acid, a solution of 20 g/DM, freshly prepared: 2 g of ascorbic acid dissolved in water, poured water to a volume of 100 cmand mixed.

Diantipyrylmethane [1], a solution of 40 g/DM: 40 g of the reagent was placed in a conical flask with a capacity of 1,000 cm, 600 cm pour thehydrochloric acid solution of 2:1, shaken until dissolved, add hydrochloric acid 2:1 to a volume of 1000 cmand mixed.

Nickel (II) chloride 6-water according to GOST 4038, a solution of 2 g/DM.

Aluminium GOST 11069 brand А999.

Solution of aluminum was 10 g/DM: 10 g of aluminum, containing titanium, is placed in a conical flask with a capacity of 1000 cm, poured with 500 cmof a solution of hydrochloric acid 1:1 and dissolved at a moderate heat, adding 1 cmof a solution of Nickel chloride (II). The solution was added 2−3 drops of hydrogen peroxide and boiled for 3−5 min to remove the excess, pour water to a volume of 600 cm, cooled to room temperature, transferred into a measuring flask with volume capacity of 1000 cm, made up to the mark with water and mix.

Titanium sponge according to GOST 17746 grade TG-90, or titanium ideny.

Standard solutions of titanium.

Solution a: 0.5 g of titanium was placed in a conical flask with a capacity of 250 cm, flow 50 cmsulphuric acid 1:5 and dissolved by heating, maintaining the initial volume with water. After dissolution, add dropwise nitric acid until the disappearance of violet colour, 2−3 drops in excess and evaporated until the appearance of white fumes of sulfuric acid. The solution was cooled, the walls of the flask is washed with water and evaporated again until the appearance of sulphuric acid fumes.

The solution was cooled, the walls of the flask is washed with 50 cmof sulfuric acid solution the molar concentration of 1 mole/DMand boil for 2−3 min. the Solution was cooled, transferred to a measuring flask with volume capacity of 1000 cm, made up with the same solution of sulfuric acid to the mark and mix.

1 cmof the solution contains 0.0005 g of titanium.

Solution B: 10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm, top up with sulphuric acid solution of molar concentration 0.5 mol/DMup to the mark and mix.

1 cmof the solution contains of 0.00005 g of titanium.

Solution: 5 cmmortar And transferred to a volumetric flask with a capacity of 250 cm, and top up with sulphuric acid solution of molar concentration 0.5 mol/DMup to the mark and mix.

1 cmof the solution contains 0,00001 g of titanium.

Solutions B and C were prepared before use.

6 analysis

6.1 the sample the sample weight in accordance with table 1 was placed in a conical flask with a capacity of 250 cm, flow 20 cmof water and carefully, in small portions, 50 cmhydrochloric acid solution 1:1. The beaker cover watch glass, heat to dissolve the sample, add 1 cmof hydrogen peroxide and boil the solution for 3−5 min.


Table 1

6.1.1 clear solution was cooled to room temperature, transferred to a volumetric flask with a capacity of 100 cm, made up to the mark with water and mix.

6.1.2 If residue remains, indicating the presence of silicon, the solution was filtered in a volumetric flask with a capacity of 100 cmthrough a filter medium density («white ribbon»), the filter cake was washed 2−3 times with hot hydrochloric acid 1:99 in portions of 10 cm(core solution).

The filter with precipitate was placed in a platinum crucible, dried, incinerated completely, preventing ignition, and calcined at 500−600 °C for 5−10 min. After cooling in the crucible add ten drops of sulfuric acid, 10 cmhydrofluoric acid and drop by drop nitric acid (approximately 1−2 cm) to obtain a transparent solution. The solution was evaporated to dryness and calcined at a temperature of 650−700 °C for 2−3 min.

To the dry residue poured 5cmof hydrochloric acid 1:1 and dissolved under moderate heating. After cooling, the solution is attached to the main solution (filtered if necessary), top up with water to the mark and mix.

6.2 Aliquot part of the solution and the solution of aluminum in accordance with table 1 was placed in a volumetric flask with a capacity of 50 cm, in the absence in the alloy of copper, add two drops of solution of copper sulphate (II), pour 1 cmof a solution of ascorbic acid, incubated for 1−2 min, poured 10 cmof the solution diantipyrylmethane, made up to the mark with water and mix.

6.3 Optical density of the solution measured after 5 min at a wavelength of 400 nm in a cuvette with a layer thickness of 30 mm for the mass fraction of titanium from 0.003% to 0,010% or 10 mm for the mass fraction of titanium from 0.010% to 0.40%. Solution comparison is the solution to which is not entered Titan (see 6.4.1 or 6.4.2).

The mass of titanium is determined according to the calibration schedule.

6.4 Construction of calibration graphs

6.4.1 When the mass fraction of titanium from 0.003% to 0,010%

In seven volumetric flasks with a capacity of 50 cmeach poured in 25 cmof a solution of aluminum in six of them measure 0,5; 1,0; 1,5; 2,0; 2,5; 3,0 cmstandard solution, which corresponds to 0,000005; 0,00001; 0,000015; 0,00002; 0,000025; 0,00003 g titanium.

6.4.2 When the mass fraction of titanium from 0.010% to 0.40%

In six volumetric flasks with a capacity of 50 cmeach poured in 25 cmof a solution of aluminium, in five of them measure 0,5; 1,0; 1,5; 2,0; 2,5 cmstandard solution B, which corresponds to 0,000025; 0,00005; 0,000075; 0,0001; 0,000125 g of titanium.

6.4.3 the solutions obtained in 6.4.1 and 6.4.2, add two drops of solution of copper sulphate (II) and then do 6.2 and 6.3. Solution comparison is the solution to which is not entered titanium.

According to the obtained values of optical density of the solutions and their corresponding masses of the titanium to build the calibration graph.

7 Processing of results

7.1 Mass percent of titanium , %, is calculated by the formula

, (1)

where is the mass of titanium in the sample solution found by the calibration schedule g;

 — the weight of the portion of the sample in aliquote part of the solution,

7.2 discrepancies in the results must not exceed the values given in table 2.


Table 2

Percentage