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GOST 24018.7-91

GOST 24018.7−91 heat-resistant Alloys on a Nickel basis. Methods for determination of carbon


GOST 24018.7−91

Group B39


STATE STANDARD OF THE USSR

ALLOYS HIGH-TEMPERATURE NICKEL-BASED

Methods for determination of carbon

Nickel-based fire-resistant alloys.
Methods for the determination of carbon


AXTU 0809

Date of introduction 1992−07−01


INFORMATION DATA

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

DEVELOPERS

V. P., Zamaraev, V. T. Ababkov, A. A. Sakharnov, Z. I. Cherkasova, E. A. Tolstoy, L. N. Dmitrov

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee on management of quality and standards from 29.05.91 N 754

3. INTRODUCED FOR THE FIRST TIME

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

   
The designation of the reference document referenced
Item number
GOST 4199−76
2.2
GOST 4207−75
2.2
GOST 4234−77
2.2
GOST 4470−79
2.2
GOST 5583−78
2.2
GOST 7565−81
1.2
GOST 9147−80
2.2
GOST 9656−75
2.2
GOST 18300−87
2.2, 3.2
GOST 22300−76
2.2, 3.2
GOST 28473−90
1.1
THAT 6−09−2705−78
2.2, 3.2
THAT 6−09−3000−78
2.2
THAT 6−09−3523−74
2.2
THAT 6−09−4128−75
2.2
THAT 48−19−57−78
3.2



This standard specifies the coulometric method and the method of IR-spectroscopy for determination of carbon (with mass fraction of carbon from 0.001 to 0.1%) in heat-resistant alloys based on Nickel.

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 28473.

1.2. Sampling — according to GOST 7565.

2. COULOMETRIC METHOD

2.1. The essence of the method

The method is based on burning a sample of the alloy in a current of oxygen at a temperature of 1350−1380 °C in the presence of flux.

The resulting carbon dioxide enters the cell containing the absorption solution with the specified pH value, which leads to a change in the acidity of the solution and the EMF indicator system pH meter. The quantity of electricity necessary to achieve the initial pH of the absorbing solution is proportional to the mass fraction of carbon in the sample, fixed colorometer integrator current, showing the direct carbon content of sample in percent.

2.2. Apparatus, reagents and solutions

Express-analyzer of any type, based on the method of coulometric titration, including in combination with automatic weights (correction mass) type KM-7426 or AV-7301 for the precision of the analysis set forth by this standard.

The combustion device of the type US-7077. It is possible to use other devices combustion, providing the temperature to 1400 °C.

Boat porcelain with GOST 9147. Pumps calcined in flowing oxygen at operating temperature and stored in a desiccator. Socket cover of the desiccator is not recommended to cover the lubricant. When you define a low carbon content (less than 0.01%) calcined pumps immediately before performing the analysis.

Tube refractory mullite length of 650−800 mm with an internal diameter of 18−22 mm.

The hook is made of heat-resistant low-carbon steel with a diameter of 3−5 mm, length 500−600 mm.

Oxygen technical GOST 5583 from coloradobased or oxygen.

Askara on the other 6−09−4128.

Potassium chloride according to GOST 4234.

Strontium chloride.

Potassium ferrocyanide according to GOST 4207.

Manganese (IV) oxide according to GOST 4470.

Boric acid according to GOST 9656.

Sodium tetraborate 10-water according to GOST 4199.

Gidroperit.

Solutions absorption and support in accordance with the type of the used analyzer.

The beach:

A mixture of tin metal on the other 6−09−2705 and iron carbonyl OS. h 13−2 on the other 6−09−3000, taken in the ratio 2:1.

The lead metal on the other 6−09−3523.

The copper oxide in the form of wire or powder, is calcined at a temperature of (800±20) °C for 3−4 h.

Allowed the use of other flooded areas.

The ethyl ether acetic acid according to GOST 22300 or technical ethyl alcohol according to GOST 18300.

2.3. Analysis

2.3.1. The device lead in working condition according to the instruction manual of the analyzer.

A portion of the alloy is 0.25−0.5 g, if necessary, washed with ether or alcohol, placed in a porcelain boat and covered with a flux linkage.

A boat with linkage of samples and smoother with a hook is introduced into the hottest part of the mullite tube and close the shutter. Set readings the digital display of the analyzer to «0» and burn the sample for 4 min.

During combustion of the sample, the absorption solution zakislate and arrow pH meter is deflected to the right from the starting position. Automatically turns on current titration, and the display is carried out continuous readout.

Analysis is complete when the needle of the pH-meter is returned to its original position, and testimony digital scoreboard do not change during one minute or change to the value of the idling score of the instrument. Open the stopper and remove the boat from the mullite tube with a hook.

2.3.2. Graduation Express analyzer is carried out on standard samples of steel of type carbon. The results of the analysis are used to adjust instrument settings.

2.4. Processing of the results

2.4.1. Mass fraction of carbon (ГОСТ 24018.7-91 Сплавы жаропрочные на никелевой основе. Методы определения углерода) in percent is calculated by the formula

ГОСТ 24018.7-91 Сплавы жаропрочные на никелевой основе. Методы определения углерода,


where ГОСТ 24018.7-91 Сплавы жаропрочные на никелевой основе. Методы определения углерода — the weight of the portion at which the calibrated device, g;

ГОСТ 24018.7-91 Сплавы жаропрочные на никелевой основе. Методы определения углерода — mass fraction of carbon, obtained by burning the sample of the sample, %;

ГОСТ 24018.7-91 Сплавы жаропрочные на никелевой основе. Методы определения углерода — mass fraction of carbon obtained from the analysis of the reference experiment, %;

ГОСТ 24018.7-91 Сплавы жаропрочные на никелевой основе. Методы определения углеродаis the mass of the analyzed sample, g.

Notes:

1. When using the analyzer complete with automatic weights the formula takes the form ГОСТ 24018.7-91 Сплавы жаропрочные на никелевой основе. Методы определения углерода.

2. The fully automated analysis on the digital display directly indicates the result of the analysis.

2.4.2. Norms of accuracy and norms of accuracy control in the determination of the mass fraction of carbon in the table.

           
    The allowable divergence, %
Mass fraction of carbon, %

The error analysis results ГОСТ 24018.7-91 Сплавы жаропрочные на никелевой основе. Методы определения углерода, %

two secondary results of the analysis performed
in various conditions ГОСТ 24018.7-91 Сплавы жаропрочные на никелевой основе. Методы определения углерода

two parallel definitions ГОСТ 24018.7-91 Сплавы жаропрочные на никелевой основе. Методы определения углерода

three parallel definitions ГОСТ 24018.7-91 Сплавы жаропрочные на никелевой основе. Методы определения углерода

the results of the analysis of a standard sample certified values ГОСТ 24018.7-91 Сплавы жаропрочные на никелевой основе. Методы определения углерода

From 0.001 to 0.002 incl.
0,0007
0,0009
0,0008
0,0009
0,0004
SV. Of 0.002 «to 0.005 «
0,0014
0,0018
0.0016 inch
0,0018
0,0008
«0,005» 0,01 «
0,0022
0,0028
0,0023
0,0028
0,0014
«0,01» 0,02 «
0,003
0,004
0,003
0,004
0,002
«0,02» 0,05 «
0,005
0,006
0,005
0,006 0,003
«0,05» 0,1 «
0,007
0,009
0,007
0,009
0,005

3. THE METHOD OF INFRARED ABSORPTION SPECTROSCOPY (IR-SPECTROSCOPY)

3.1. The essence of the method

The method is based on burning a sample of the alloy in a current of oxygen at a temperature of 1700 °C in the presence of flux.

Mass fraction of carbon in percent is determined by the amount of the formed carbon dioxide a measurement of the amount of its absorbed infrared rays.

3.2. Equipment, reagents

The analyzer of any type, based on the principle of IR spectroscopy and ensuring the accuracy of the analysis required by this standard.

Crucibles refractory ceramic for NTD, pre-calcined in a muffle furnace at a temperature of 1000−1100 °C for 3−4 h, stored in desiccator. Socket cover of the desiccator is not recommended to cover the lubricant.

The beach: a mixture of tungsten metal SVC on the other 48−19−57 and tin metal on the other 6−09−2705, taken in the ratio 1:1.

Allowed the use of other flooded areas.

The ethyl ether acetic acid according to GOST 22300 or technical ethyl alcohol according to GOST 18300.

3.3. Analysis

3.3.1. The device lead in working condition according to instructions.

A sample of alloy weighing 1.0 g and, if necessary, washed with ether or alcohol, is placed in a ceramic crucible, cover linkage flux in the ratio 1:2 and carry out the analysis according to the instruction manual of the analyzer.

3.3.2. The calibration of the analyzer is carried out according to standard samples of the carbon steel type. The results of the analysis are used for adjusting the settings of the analyzer.

3.4. Processing of the results

3.4.1. Mass fraction of carbon in percent is determined directly by the digital display of the analyzer.

3.4.2. Norms of accuracy and norms of accuracy control in the determination of the mass fraction of carbon in the table.