GOST 12344-88
GOST 12344−88 Steel alloyed and high alloy. Methods for determination of carbon
GOST 12344−88
Group B39
STATE STANDARD OF THE USSR
STEEL ALLOYED AND HIGH-ALLOYED
Methods for determination of carbon
Alloyed and high-alloyed steels.
Methods of carbon determination
AXTU 0809
Valid from 01.01.90
to 01.07.95*
__________________________
* Expiration removed by Protocol No. 4−93
The interstate Council for standardization, Metrology
and certification (I & C N 4, 1994). — Note the CODE.
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of ferrous metallurgy of the USSR
PERFORMERS
S. M. Novokshenov, V. P., Zamaraev, A. I. Orzechowska
2. APPROVED AND put INTO EFFECT by decision of the USSR State Committee for standards from
3. REPLACE GOST 12344−78
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Item number |
| GOST 546−79 |
2.3 |
| GOST 860−75 |
2.3 |
| GOST 2603−79 |
2.3 |
| GOST 4470−79 |
2.3 |
| GOST 5583−78 |
2.2 |
| GOST 9147−80 |
2.2 |
| GOST 13610−79 |
2.3 |
| GOST 16539−79 |
2.3 |
| GOST 20560−81 |
1.1 |
This standard sets the coulometric method for the determination of carbon (with mass fraction of carbon from 0.002 to 2.0%) and the method of infrared spectroscopy (at a mass fraction of carbon from 0.001 to 2.0%).
1. GENERAL REQUIREMENTS
1.1. General requirements for methods of analysis GOST 20560−81.
2. COULOMETRIC METHOD FOR DETERMINING CARBON
2.1. The essence of the method
The method is based on the combustion of a sample of steel in a current of oxygen in presence of flux at a temperature of 1300−1400 °C, the absorption of the formed carbon dioxide absorption by a solution with a particular initial pH value and subsequent measurement (in the apparatus for coulometric titration) the amount of electricity spent to restore the original pH value, which is proportional to the mass fraction of carbon in the linkage sample.
2.2. Equipment
Coulometric installation (drawing). Allowed the use of installations of any type, including complete with automatic weights (correction mass), providing the accuracy of the analysis required by this standard.
When you use automatic weights the measurement error of the mass of sample should not exceed ±0.001 g.
Drawing
1 — oxygen tank (with a purity not less than 95%) according to GOST 5583−78 (use oxygen from coloradobased);
2, 3 reducers reducing the pressure of the oxygen; 4 — rotameter with pneumatic regulation of the flow of oxygen (from 0.2 to 2.0 DM/min);
5 — tube refractory mullite designed for burning of sample; 6 — tube furnace, providing temperatures up to 1400 °C;
7 — a filter-absorber is filled with cotton wool for cleaning the products of combustion from the solid particles of oxides; 8 — gauge Express analyzer;
9 — pair electrode pH meter; 10 — autoregulated device coulometric titration; 11 — digital Board;
12 — anodic compartment of the sensor; 13 — plastic partition between the sensors; 14 — cathode compartment sensor;
15 — mullite refractory tube, is designed for hot clean oxygen
(in the determination of carbon with a mass fraction of more than 0.03%, the hot purging of oxygen can not be used);
16 — column filled with oscarito to clean oxygen from carbon dioxide.
Boat porcelain with GOST 9147−80 or other normative and technical documentation, pre-calcined in flowing oxygen at operating temperature.
In the determination of carbon less than 0.05% pumps calcined directly before analysis, cooled to room temperature and stored in a desiccator.
Tubular resistance furnace, providing temperatures up to 1400 °C allows the use of induction furnaces.
The hook is made of heat-resistant low-carbon steel with a length of 300−600 mm, a diameter of 3−5 mm.
2.3. Reagents and solutions
Absorption and support solutions in accordance with the type of the used coulometric setup.
Marshes carbonyl iron radio GOST 13610−79 OS. h or other normative and technical documentation, tin GOST 860−75 or other normative and technical documentation, and copper oxide according to GOST 16539−79 or other normative and technical documentation, the copper metal according to GOST 546−79 or other regulatory-technical documentation.
Allowed the use of other flooded areas.
Mass fraction of carbon in the flux should not exceed the appropriate value allowable discrepancies between the results of parallel measurements.
Ethers: sulphuric acid (medical) or diethyl ether. Allowed to use other volatile organic solvents: acetone according to GOST 2603−79, chloroform, etc.
Manganese dioxide according to GOST 4470−79.
Gidroperit.
2.4. Preparation for assay
Before analysis the installation of a drive in accordance with the instructions supplied with the device.
Before starting work, and after replacement of the mullite tubes burn two or three arbitrary linkage of steel with a mass fraction of carbon of 1%.
In determining the carbon materials with a high mass fraction of sulphur (free-cutting steel), to eliminate the effect of sulfur dioxide used manganese dioxide or gidroperit, which is placed in the filter-absorber (7).
The calibration of an instrument performed on standard specimens of carbon steel.
The control of correctness of analysis results set by standard samples of steels corresponding in chemical composition and determine the concentrations of the analyzed materials.
To control the correctness of the results of analysis with each batch of samples analyzed standard samples of steel at least twice per shift.
The arithmetic average of the results of the analysis of standard sample should not differ from the certified values by more than 0.6 or 0.5
allowable absolute differences established for the respective concentration range when performing analysis of the two (three) parallel batches.
2.5. Analysis
In the analysis of alloy steels in the sample of steel weighing 0.25−0.5 g (depending on the mass fraction of carbon in steel and its chemical composition) of calcined placed in a porcelain boat and add 0.5−1 g of copper or iron or any other beach.
In the analysis of high-alloyed steels used 1.5 g of a mixture of marshes, consisting of tin and iron or oxides of copper and iron taken in both cases in a ratio of 1:2.
When the mass fraction of carbon in the steel less than 0.20% of the portion recommended to be washed with ether or other volatile organic solvent and air dry.
The boat with the charge of metal and flux is placed in the most heated portion of the porcelain tube, which quickly closed the metal gate: press the button «reset», while the indicator digital display set to «zero».
In the burning process of mounting the metal on the digital display there is a continuous reference.
The analysis is complete, if the reading scoreboard does not change within one minute, or changes to the value of the idling score of the instrument.
In parallel, through all stages of the analysis, conduct the analysis of control experience. For this purpose calcined in a porcelain boat is placed corresponding to the flux and burn it at operating temperature during time spent on the burning of the sample of the analyzed material. The duration of the measurement (combustion of sample metal) of 1.5−3 min depending on the chemical composition of the analyzed material.
2.6. Processing of the results) in percent is calculated by the formula
where — the weight of the portion in which the calibrated device, g;
— reading digital display of the device, the resulting combustion of the sample of the analyzed material, %;
— the arithmetic mean of the readings obtained from the combustion of smoother, % (reference experiment);
is the mass of the analyzed sample, g.
When using appliances with automatic weights (correction mass) mass fraction of carbon in percent is calculated by the formula
) or two (
) of parallel measurements (at confidence probability
=0,95) must not exceed the value of permissible differences for the relevant concentration range given in the table.
Mass fraction of carbon, % |
Allowable absolute differences, % | |
| From 0.001 to 0.002 incl. |
0,0008 | 0,0007 |
| SV. Of 0.002 «to 0.005 « |
0,0010 | 0,0008 |
| «0,005» 0,01 « | 0,0020 |
0,0017 |
| «0,01» 0,02 « |
0,004 | 0,003 |
| «0,02» 0,05 « |
0,006 | 0,005 |
| «0,05» 0,10 « |
0,010 | 0,008 |
| «0,10» 0,2 « |
0,015 | 0,012 |
| «0,2» 0,5 « |
0,020 | 0,017 |
| «0,5» 1,0 « | 0,030 |
0,025 |
| «1,0» 2,0 « |
0,050 | 0,04 |
3. INFRARED ABSORPTION METHOD
3.1. The essence of the method
The method is based on the combustion of a sample of steel in a current of oxygen in presence of flux at a temperature of 1700 °C and determining the quantity of formed carbon dioxide by measuring its absorption of infrared radiation.
3.2. Equipment and reagents
Any type of automatic analyzer, based on the principle of absorption of infrared radiation and to ensure the accuracy of the analysis required by this standard.
Ether sulfate (medical). Allowed to use other volatile organic solvents: acetone, chloroform, etc.
The smoother used depending on the type of the used analyzer.
3.3. Preparation for assay
Before analysis the installation of a drive in accordance with the instructions supplied with the device.
The calibration of an instrument performed on standard specimens of carbon steel.
The control of correctness of analysis results set by standard samples of steels corresponding in chemical composition and determine the concentrations of the analyzed materials. To control the correctness of the results of analysis with each batch of samples analyzed standard samples of steel at least twice per shift.
The arithmetic average of the results of the analysis of standard sample should not differ from the certified values by more than 0.6 or 0.5
allowable absolute differences established for the respective concentration range when performing analysis of the two (three) parallel batches.
3.4. Analysis
The analysis is carried out in accordance with the instructions supplied with the device.
When the mass fraction of carbon in the steel less than 0.20% of the portion recommended to be washed with ether or other volatile organic solvent and air dry.
In parallel through all stages of the analysis carried out the analysis of control experience.
The duration of the measurement (the burning of the sample metal) — 45 p
3.5. Processing of the results) in percent is calculated by the formula
where — reading digital display of the device, the resulting combustion of the sample of the analyzed material, %;
— the testimony of a digital display device, resulting from the burning flux, % (reference experiment).
) or two (
) of parallel measurements (at confidence probability
=0,95) must not exceed the value of permissible differences for the relevant concentration range given in the table.
