GOST 26473.10-85
GOST 26473.10−85 Alloys and alloys based on vanadium. Methods for determination of chromium and vanadium (with Change No. 1)
GOST 26473.10−85
Group B59
STATE STANDARD OF THE USSR
ALLOYS AND MASTER ALLOYS BASED ON VANADIUM
Methods for determination of chromium and vanadium
Vanadium base alloys and alloying elements. Methods for determination of chromium and vanadium Corporation
AXTU 1709
Valid from 01.07.86
to 01.07.91*
_______________________________
* Expiration removed
by the decree of Gosstandart of the USSR from
(IUS N 8, 1991). — Note the manufacturer’s database.
DEVELOPED by the Ministry of nonferrous metallurgy of the USSR
PERFORMERS
Yu. A. Karpov, E. G. Nembrini, V. G., Miscreants, V. V. Nedler, V. M. Mikhailov, L. G. Agapova, G. N. Andrianov, A. V. Antonov, V. D. Dozen, M. A. Desyatkova, T. I. Kirillova, L. I. Kirsanov, I. E. Korepin, V. A. Orlova, N. Rasnitsyn, N. Suvorova, N. L. Tomasev, M. W. Schmidt, L. N. Filimonov
INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
Member Of The Board Of A. P. Snurnikov
APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on standards of 25 March 1985 N 752
The Change N 1, approved and put into effect by the Decree of the USSR State Committee on management of quality and standards from
Change No. 1 made by the manufacturer of the database in the text IUS N 2, 1990
This standard specifies the titrimetric method for the determination of chromium (from 5 to 10% and from 30 to 40%), and titrimetric method of sequential determination of vanadium (30−40%) and chromium (5 to 10% and from 30 to 40%) in alloys and master alloys based on vanadium, the contents of related components which are shown in table.1.
Table 1
| The accompanying component |
Mass fraction, %, not more |
| Aluminium |
50 |
| Silicon |
1 |
| Iron | 5 |
| Manganese | 2,5 |
| Molybdenum | 25 |
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 26473.0−85.
2. TITRIMETRIC METHOD FOR THE DETERMINATION OF CHROMIUM
The method is based on oxidation of the chromium to the hexavalent state neccersarily ammonium in the presence of a catalyst (silver nitrate) and subsequent titration of the excess of salt Mora, entered for recovery of hexavalent chromium, a solution of potassium permanganate.
2.1. Apparatus, reagents and solutions
Analytical scale.
Libra technical.
Tile electric.
Conical flasks with a capacity of 500 cm.
Glasses chemical glass with a capacity of 500 cm.
Measuring beakers with a capacity of 50 and 500 cm.
Pipettes with a capacity of 50 cmwith no divisions.
Burette with a capacity of 25 cmwith a scale division of 0,05 cm
.
Sulfuric acid GOST 4204−77 and diluted 1:1 and 1:5.
Orthophosphoric acid according to GOST 6552−80.
The mixture of acids is prepared as follows: to 320 cmof sulphuric acid diluted 1:1, poured 80 cm
of orthophosphoric acid, adjusted to 1 DM
with water, mix.
Ammonium neccersarily according to GOST 20478−75, solution concentration of 250 g/DM.
Sodium chloride according to GOST 4233−77, solution concentration of 50 g/DM.
Silver nitrate according to GOST 1277−75, a solution concentration of 1 g/DM.
Manganese (II) sulfate 5-water according to GOST 435−77.
Potassium permanganate, solution molar concentration of the equivalent 0,1 mol/DM(oxidation reaction of iron in acid medium); prepared from standard-titer, 0.1 N.
Potassium dichromate, solution molar concentration of the equivalent 0,1 mol/DM(oxidation reaction of iron in acid medium); prepared from standard-titer, 0.1 N.
Salt of protoxide of iron and ammonium double sulfate (salt Mora) according to GOST 4208−72, a solution of concentration 0.1 mol/DM: 39,5 g of salt Mora is placed in a beaker with capacity of 500 cm
, is dissolved in 400 cm
of water containing 10 cm
of concentrated sulfuric acid, cooled to room temperature. The solution was transferred to a volumetric flask with a capacity of 1 DM
and bring to mark with water.
N-phenylanthranilic acid solution with a concentration of 1 g/DM: 0.1 g of sodium carbonate was dissolved with heating in 50 cm
of water, add 0.1 g phenylanthranilic acid and the volume was adjusted to 100 cm
water.
Sodium carbonate
to GOST 83−79.
2.1.1. Establish the relationship between solutions of salt Mora and potassium dichromate (): in a conical flask with a capacity of 250 cm
is introduced from the burette 10 cm
of a solution of potassium dichromate, poured 20 cm
of sulphuric acid, diluted 1:5, five drops of salt solution phenylanthranilic acid and titrated with a solution of salt Mora before moving blue-violet color in green.
The ratio () of the volume of the solution of salt Mora and the potassium dichromate is calculated by the formula:
where is the volume of potassium dichromate solution taken for titration, cm
;
— the volume of salt solution Mora, used for titration, sm
.
Ratio () is set before application of salt Mora.
2.1.2. Establish the relationship between solutions of salt Mora and potassium permanganate (): in a conical flask with a capacity of 500 cm
pour 200cm
of water, 10 cm
of sulphuric acid, diluted 1:5, is introduced from the burette 15 cm
of salt solution Mora and titrated with potassium permanganate solution until the appearance of slightly pink color persisting for 1 min.
The ratio () of the volume of the solution of salt Mora and potassium permanganate is calculated by the formula
where — the volume of salt solution Mora, taken for titration, cm
;
— the volume of potassium permanganate solution consumed for titration, sm
.
Ratio () is set prior to the determination of chromium.
2.2. Preparation for assay
2.2.1. Dissolution of the sample test portion and preparation of solution for determination of chromium was carried out as described in GOST 26473.4−85.
2.2.2. To perform the assay
In a conical flask with a capacity of 500 cmpipetted 50 cm
«the main solution» (see GOST 26473.4−85) containing 0.01−0.04 g of chrome, poured 20 cm
of a mixture of acids, 150 cm
of water and heated to boiling. To the solution was added 10 cm
of a solution of silver nitrate, 60−80 cm
solution naternicola ammonium, boil 1−2 min, add a few crystals of sulphate of manganese and boil the solution until full oxidation of chromium (appearance of pink colour manganese acid) until complete decomposition of the excess ammonium naternicola (termination of allocation of small bubbles).
Then pour the 6−10 cmsodium chloride solution and boil until you move the crimson color of the solution yellow.
The solution was cooled to 15−17 °C, flow 15 cmof salt solution Mora and titrate the excess of Mohr salt solution of potassium permanganate to the appearance of a slightly pink color persisting for 1 mi
B.
2.3. Processing of the results
2.3.1. Mass fraction of chromium () in percent is calculated by the formula
where — the volume of salt solution Mora, added to the analyzed solution, cm
;
— the volume of potassium permanganate solution consumed for titration of the excess of salt Mora, cm
;
— the ratio of the volume of the solution of salt Mora and potassium dichromate;
— the ratio of the volume of the solution of salt Mora and potassium permanganate;
0,001733 mass concentration of salt solution Mora, expressed in g/cmchrome;
— capacity volumetric flasks, cm
;
— aliquotes volume of the solution taken for titration, cm
;
— the weight of the portion of the analyzed samples
s,
2.3.2. The values of permissible differences are listed in table.2.
Table 2
| Mass fraction of chromium, % | Allowable difference, % |
| 5,0 |
0,5 |
| 10,0 |
0,6 |
| 30,0 |
1,0 |
| 40,0 |
1,2 |
(Changed edition, Rev. N 1).
2.3.3. The method used in the disagreement in assessing the quality of alloys and ligatures.
3. TITRIMETRIC METHOD OF SEQUENTIAL DETERMINATION OF VANADIUM AND CHROMIUM
The method is based on the sequential titration of vanadium (V) and vanadium with chromium salt solution Mora in the sulfate medium.
Vanadium is oxidized to pentavalent state with potassium permanganate. For oxidation of vanadium and chromium in the higher valency state is used neccersarily ammonium in the presence of a catalyst (nitrate of silver).
3.1. Apparatus, reagents and solutions
Analytical scale.
Libra technical.
Tile electric.
Glasses chemical glass with a capacity of 400 and 500 cm.
Conical flasks with a capacity of 250 and 500 cm.
Volumetric flasks with a capacity of 100 cmand 1 DM
.
Pipettes with a capacity of 10 cmwith no divisions.
Burettes with a capacity of 10 and 25 cmwith a scale division of 0,05 cm
.
Measuring beakers with a capacity of 50 and 500 cm.
Sulfuric acid GOST 4204−77 and diluted 1:3.
Nitric acid GOST 4461−77 and diluted 1:1.
Orthophosphoric acid according to GOST 6552−80.
Oxalic acid according to GOST 22180−76, solution concentration of 10 g/DM.
Silver nitrate according to GOST 1277−75, solution concentration of 2.5 g/DM.
Ammonium neccersarily according to GOST 20478−75, solution concentration 100 g/DM.
Sodium chloride according to GOST 4233−77, solution concentration of 50 g/DM.
Potassium permanganate according to GOST 20490−75, a solution concentration of 150 g/DM.
Sodium carbonate according to GOST 83−79.
Potassium dichromate, solution molar concentration of the equivalent 0,1 mol/DM(oxidation reaction of iron in acid medium); prepared from standard-titer, 0.1 N.
Salt of protoxide of iron and ammonium double sulfate (salt Mora) according to GOST 4208−72, a solution of concentration 0.1 mol/DM: 39,5 g of salt Mora is placed in a beaker with capacity of 500 cm
, is dissolved in 400 cm
of water containing 10 cm
of concentrated sulfuric acid, stirred and cooled to room temperature. The solution was transferred to volumetric flask with a capacity of 1 DM
and bring to mark with water.
N-phenylanthranilic acid solution with a concentration of 1 g/DM: 0.1 g of sodium carbonate was dissolved with heating in 50 cm
of water, add 0.1 g phenylanthranilic acid and the volume was adjusted to 100 cm
water.
(Changed edition, Rev. N 1).
3.1.1. Establish the relationship between solutions of salt Mora and dichromate Kali
I () according to claim
3.2. Preparation for assay
A portion of the sample weighing 1 g is placed in a beaker with a capacity of 400 cm, 120 cm pour the
sulfuric acid solution, diluted 1:3, heated to boiling and the hot solution poured 20−25 cm
of concentrated nitric acid. If the sample is poorly soluble, then added another 15−20 cm
of nitric acid, heated to complete dissolution of the sample, was boiled down to 50−70 cm
, cooled to room temperature, transferred to a volumetric flask with a capacity of 100 cm
and adjusted to the mark with water (stock solution).
3.3. To perform the assay
3.3.1. Definition of vanadium: in a conical flask with a capacity of 500 cmpipetted 10 cm
basic solution (p.3.2), pour 15−20 cm
of concentrated sulfuric acid, is evaporated twice to release the vapours of sulphuric anhydride, cooled to room temperature, dilute with water to 100 cm
, cooled in cold water to 15−20 °C and poured dropwise a solution of potassium permanganate until a stable pink color. After 10−15 minutes the excess of potassium permanganate solution to destroy the oxalic acid, priliva it dropwise until the disappearance of the pink coloring and 1−2 drops in excess. Pour 5 cm
of a solution of orthophosphoric acid 5−7 drops of salt solution phenylanthranilic acid and titrate the vanadium salt solution Mora to the transition of color from red-violet to green (
) (retain solution for determination of chromium).
3.3.2. Definition of chromium: solution after determining it to vanadium (p.3.3.1) dilute with water to 250 cm, heated to 50−70 °C, pour 10 cm
of a solution of silver nitrate, 50 cm
solution naternicola ammonium priliva gradually in small portions, and heated until the appearance of pink colour manganese acid and boil until the termination of allocation of bubbles of oxygen. The walls of the flask is washed with water and again boil for 2−3 min. Then pour 10 cm
of sodium chloride solution and heated until the disappearance of the crimson color. The solution was cooled to room temperature, pour 5 cm
of a solution of orthophosphoric acid 5−7 drops of salt solution phenylanthranilic acid, 10 cm
of sulphuric acid diluted 1:1, incubated for 2−3 minutes, shaking occasionally, and titrate the vanadium and chromium with a solution of salt Mora until the solution colour from red-violet to green (
)
.
3.4. Processing of the results
3.4.1. Mass fraction of vanadium () in percent is calculated by the formula
where — the volume of salt solution Mora, used for titration, cm
;
0,005095 mass concentration of salt solution Mora, expressed in g/cmvanadium;
— the ratio of the volume of the solution of salt Mora and potassium dichromate;
— capacity volumetric flasks, cm
;
— aliquotes volume of the solution taken for titration, cm
;
— the weight of the portion of the sample, g
.
3.4.2. Mass fraction of chromium () in percent is calculated by the formula
where — the volume of salt solution Mora, used for titration of the amounts of vanadium and chromium, cm
;
— the volume of salt solution Mora, used for titration of vanadium, cm
;
0,001733 mass concentration of salt solution Mora, expressed in g/cmchrome;
— the ratio of the volume of the solution of salt Mora and potassium dichromate;
— volume of the volumetric flask, cm
;
— aliquotes volume of the solution taken for titration, cm
;
— the weight of the portion of the analyzed samples
s,
3.4.3. The values of permissible differences are listed in table.3.
Table 3
| Mass fraction, % |
Allowable difference, % | |
| Vanadium | 30,0 | 0,9 |
| 40,0 | 1,2 | |
| Chrome | 5,0 | 0,7 |
| 10,0 | 0,8 | |
| 30,0 | 1,3 | |
| 40,0 | 1,6 | |
(Changed edition, Rev. N 1).
