GOST 3240.7-76
GOST 3240.7−76 magnesium Alloys. Method for the determination of calcium (with Change No. 1)
GOST 3240.7−76
Group B59
INTERSTATE STANDARD
MAGNESIUM ALLOYS
Method of determination of calcium
Magnesium alloys.
Method for determination of calcium
ISS 77.120.20
AXTU 1709
Date of introduction 1978−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of aviation industry of the USSR
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. REPLACE GOST 3240−56 sec. IX in determining the calcium content
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
The designation of the reference document referenced |
Section number, paragraph |
GOST 8.315−97 |
Sec. 5 |
GOST 61−75 |
Sec. 2 |
GOST 804−93 |
Sec. 2 |
GOST 3118−77 |
Sec. 2 |
GOST 3240.0−76 |
1.1 |
GOST 4517−87 |
Sec. 2 |
GOST 5457−75 |
Sec. 2 |
GOST 8677−76 |
Sec. 2 |
GOST 11069−2001 |
Sec. 2 |
GOST 25086−87 |
Sec. 5 |
5. Limitation of actions taken by Protocol No. 2−92 of the Interstate Council for standardization, Metrology and certification (ICS 2−93)
6. EDITION with Change No. 1, approved in June 1987 (IUS 11−87)
This standard sets flame photometric method for the determination of calcium (when calcium mass fraction from 0.01 to 0.2%).
The method is based on dissolving the samples in hydrochloric acid, adding a solution of 8-hydroxyquinoline to suppress the damping of radiation of calcium, and measuring the intensity of molecular bands of calcium oxide excited in an acetylene-air flame in the field 622,3 nm. Height fotometricheskogo phase 3, see
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 3240.0.
2. APPARATUS, REAGENTS AND SOLUTIONS
The flame photometer or spectrophotometer.
Hydrochloric acid according to GOST 3118, diluted 1:1.
Acetic acid according to GOST 61, 10% solution.
8-hydroxyquinoline 5% solution of acetic acid.
Magnesium chloride, solution; is prepared as follows: 100 g of magnesium GOST-804 brand Мг1 is dissolved in 1500 cmof hydrochloric acid and dilute with water to 2000 cm.
1 cmof the solution contains 0.05 g of magnesium.
Aluminum chloride, solution; is prepared as follows: 100 g of aluminum according to GOST 11069марки A7 are dissolved in 1600 cmhydrochloric acid and dilute with water to 2000 cm.
1 cmof the solution contains 0.05 g of aluminum.
Calcium chloride, standard solution; is prepared as follows: 0,140 g of calcium oxide GOST 8677, calcined at 700±10 °C to constant weight, dissolved in 25 cmof hydrochloric acid and dilute with water to 1000 cm.
1 cmof the solution contains 0.1 mg of calcium.
Acetylene in cylinders GOST 5457.
Bidistilled water, obtained according to GOST 4517.
(Changed edition, Rev. N 1).
3. ANALYSIS
3.1. 1 g of alloy are placed in a conical flask with a capacity of 250 cm, thoroughly washed with hydrochloric acid and water. Then add 15 cmof water, dissolve the sample in 15 cmof hydrochloric acid administered 50 cmof a solution of 8-hydroxyquinoline, the solution was transferred to volumetric flask with a capacity of 100 cm, diluted with water, thoroughly mixed, injected into the atomizer of the photometer and photometric using the molecular strip of calcium oxide 622,3 nm. Solution comparison is the solution of the reference experiment. Mass fraction of calcium find for the calibration schedule.
3.2. Build graduirovochnyh graphics
In six volumetric flasks with a capacity of 100 cm, introduce a solution of aluminum chloride, the number of milliliters which is calculated by the formula where is the mass fraction of aluminium in the samples in percent, solution of chloride magnesium in the amount of , 0; 1,0; 2,0; 5,0; 10,0 and 20,0 cmstandard solution of calcium, which corresponds to the mass fraction of calcium in the samples 0,0; 0,01; 0,02; 0,05; 0,1 and 0,2%, add 50 cmof a solution of 8-hydroxyquinoline, diluted with bidistilled water to the mark and photometrist, as indicated in paragraph 3.1.
Calibration curve building, laying on the x-axis mass fraction of the calcium in percentage and the y — axis the difference of the readings obtained in fotomaterialy solutions containing calcium, and the zero solution.
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of calcium in percent determined by the calibration schedule.
4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in the table.
Mass fraction of calcium, % |
The absolute allowable difference, % |
From 0.01 to 0.02 |
0,002 |
SV. A 0.02 «to 0.04 |
0,003 |
«Of 0.04» to 0.10 |
0,005 |
«To 0.10» to 0.20 |
0,015 |
5. CONTROL OF MEASUREMENT ACCURACY
To control the accuracy of measuring the mass fraction of calcium is from 0.01 to 0.2% use industry standard samples and standard samples of the enterprise of magnesium alloys, issued in accordance with GOST 8.315. Accuracy control measurement is carried out in accordance with GOST 25086.
Control the accuracy of measuring the mass fraction of calcium may be performed by a method of additives.
Sec. 5. (Added, Rev. N 1).