GOST 24018.8-91
GOST 24018.8−91 heat-resistant Alloys on a Nickel basis. Methods of determining sulphur
GOST 24018.8−91
Group B39
STATE STANDARD OF THE USSR
ALLOYS HIGH-TEMPERATURE NICKEL-BASED
Methods of determining sulphur
Nickel-based fire-resistant alloys.
Methods for the determination of sulphur
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
3. INTRODUCED FOR THE FIRST TIME
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Item number |
| GOST 3118−77 |
2.2, 4.2 |
| GOST 4108−72 |
2.2 |
| GOST 4145−74 |
4.2 |
| GOST 4202−75 |
4.2 |
| GOST 4204−77 |
4.2 |
| GOST 4232−74 |
4.2 |
| GOST 4234−77 |
2.2 |
| GOST 5583−78 |
2.2, 4.2 |
| GOST 7565−81 |
1.2 |
| GOST 9147−80 |
2.2, 4.2 |
| GOST 10163−76 |
4.2 |
| GOST 10929−76 |
2.2 |
| GOST 14261−77 |
2.2 |
| GOST 18300−87 |
2.2, 3.2, 4.2 |
| GOST 20490−75 |
4.2 |
| GOST 22300−76 |
2.2, 3.2, 4.2 |
| GOST 22551−77 |
2.2 |
| GOST 28473−90 |
1.1 |
| THAT 6−09−1948−81 |
2.2, 3.2, 4.2 |
| THAT 6−09−2705−78 |
3.2 |
| THAT 6−09−3000−78 |
2.2, 3.2 |
| THAT 6−09−3880−87 |
4.2 |
| THAT 6−09−4128−75 |
2.2, 4 2 |
| THAT 48−19−57−78 |
3.2 |
This standard specifies the coulometric and infrared absorption (at a mass fraction of sulfur from 0.001 to 0.02%) and titrimetric iodide todaty (when the mass fraction of sulfur from 0.005% to 0.02%) methods for determination of sulfur in superalloys 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 formed sulfur dioxide is absorbed by the 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 sulfur in the sample, fixed colorometer integrator current, showing the immediate sulphur content of the sample in percent.
2.2. Apparatus, reagents and solutions
Express-analyzer of the type as-7412, as-7512, AC-7932, AUS-7544 including complete with automatic weights (correction mass) type AV-7301 or KM-7426. Allowed the use of the analyzers of another type, ensure the accuracy of the analysis required by this standard.
The combustion device of the type US-7077. Allowed the use of burners of another type, providing the temperature to 1400 °C.
Boat porcelain with GOST 9147.
Pumps pre-calcined in flowing oxygen at operating temperature and stored in a desiccator. Socket cover of the desiccator is not recommended to cover the lubricant. In determining sulphur less than 0.005% pumps calcined directly before 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.
Technical oxygen gas according to GOST 5583.
Askara on the other 6−09−4128.
Hydrochloric acid according to GOST 3118 or GOST 14261, solution 0,1 mol/DM.
Potassium chloride according to GOST 4234.
Barium chloride according to GOST 4108.
Hydrogen peroxide according to GOST 10929, a solution of 300 g/DM.
Quartz sand according to GOST 22551.
The ethyl ether acetic acid according to GOST 22300 or ethyl alcohol according to GOST 18300.
The beach:
Vanadium (V) oxide, h h. on the other 6−09−1948, pre-calcined at a temperature of 400−450 °C for 3−4 h.
The flux stored in a closed boxe in a desiccator.
Carbonyl iron OS. h 13−2 on the other 6−09−3000.
Absorption and support solutions in accordance with the type of the used analyzer.
2.3. Analysis
2.3.1. The device lead in working condition according to the instruction manual of the analyzer.
In a porcelain boat is placed 0.2 g of the flux (vanadium pentoxide), a portion of the alloy 0.5 g, if necessary, washed with ether or alcohol, and cover the top 0.2 g flux (vanadium pentoxide). A boat with suspension of sample and flux was placed with a hook to the tube for burning, close the shutter, set the readings of the digital display 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 or change to the value of the idling score of the instrument; recorded readings digital display, open the stopper and remove the boat from the tube.
2.3.2. Graduation Express analyzer is carried out on standard samples of steel of type carbon. The results of the analysis are used for adjusting the settings of the analyzer.
2.4. Processing of the results
2.4.1. Mass fraction of sulfur () in percent is calculated by the formula
where is the mass of the sample, which was calibrated device, g;
— mass fraction of sulfur, obtained in the analysis sample of the sample, %;
— mass fraction of sulfur obtained in the determination of the reference experiment, %;
is the mass of the analyzed sample, g.
Notes:
1. If you use the analyzer in a set with the concealer mass formula takes the form 
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 sulphur mass fraction given in the table.
| The allowable divergence, % | |||||
| Mass fraction of sulfur, % | The error analysis results |
two secondary results of the analysis performed under various conditions |
two parallel definitions |
three parallel definitions |
the results of the analysis of a standard sample certified values |
| From 0.001 to 0.002 incl. |
0,0007 | 0,0009 | 0,0008 |
0,0009 |
0,0004 |
| SV. Of 0.002 «to 0.005 « |
0.0016 inch |
0,0020 |
0.0016 inch |
0,0020 | 0,0010 |
| «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 |
3. INFRARED ABSORPTION METHOD (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 sulfur in percent is determined by the amount of the formed sulfur 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 in the NTD.
Before use, the crucible is calcined in a muffle furnace at a temperature of 900−1000 °C for 3−4 h and 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 in the ratio 1:1. A mixture of vanadium (V) oxide on the other 6−09−1948 and iron carbonyl OS. h 13−2 on the other 6−09−3000 in the ratio 1:5.
The ethyl ether acetic acid according to GOST 22300 or ethyl alcohol according to GOST 18300.
3.3. Analysis
3.3.1. The device lead in working condition according to the instruction manual of the analyzer
In the ceramic crucible was placed a portion of the alloy 1.0 g if necessary, washed with ether or alcohol and coated at approximately 2.0 g of flux. The analysis is carried out 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 sulfur 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 sulphur mass fraction given in the table.
4. TITRIMETRIC METHOD
4.1. 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 sulfur dioxide enters the absorption vessel, is absorbed in water to form sulphurous acid, which octarepeat solution of iodide of potassium Iodate in the presence of starch indicator.
4.2. Apparatus, reagents and solutions
Installation for sulfur determination titrimetric method given on features.1, consists of oxygen cylinder 1 (use oxygen from coloradobased); a reducing valve 2; a gas washing bottle 3, containing a solution of potassium permanganate with a mass concentration of 40 g/lsolution of potassium hydroxide with a mass concentration of 400 g/DM
; the flask Tishchenko 4 with concentrated sulfuric acid;
-shaped tube 5 filled with anhydrous calcium chloride or angerona (allowed to carry out dry cleaning of oxygen: instead of the flasks 3, 4 and 5 use gorkaltseva up, the column and Astarita
-shaped tube, contains the first half (downstream) asbestos, impregnated with manganese dioxide, and the second — anhydro); 6 rotameter; 7-way tap; the mullite tube 8; horizontal furnace 9 with carrickbrennan heaters, providing temperature up to 1400 °C; the tube 10 with a spherical extension, filled with cotton wool to trap particles of combustion products; two-way tap 11, which was used for start-up of the gas mixture in the absorber, burettes with a capacity of 12 25 cm
; glass absorption vessel 13 with a height of 250 mm and a diameter of 40 mm; the vessel includes l-shaped tube 14, terminating in barbaram 15 for spraying gas to absorb the sulfur dioxide by water; of a glass vessel comparison 16 with a height of 250 mm and a diameter of 40 mm.
Damn.1. Installation diagram for sulfur determination titrimetric method
Installation diagram for sulfur determination titrimetric method
Damn.1
Allowed the use of an absorption cell consisting of two glass vessels with an internal diameter of 30−35 mm with a height of 150 mm (Fig.2). In the left-hand vessel 1 is absorbed sulphur dioxide, and titration of the resulting solution of sulphurous acid, in the right vessel 2 is solution comparisons. The vessels have a common drain, which closes the three-way crane 3 and is connected by a glass bridge 4.
Damn.2. The scheme of the absorption cell
The scheme of the absorption cell
Damn.2
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.
Mullite tube with a 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 length of 500−600 mm, with a diameter of 3−5 mm.
Technical oxygen gas according to GOST 5583.
Potassium ignominously according to GOST 4202.
Potassium iodide according to GOST 4232.
Potassium hydroxide, solution with the mass concentration of 400 g/DM.
Potassium permanganate according to GOST 20490, solution with mass concentration 40 g/lsolution of potassium hydroxide with a mass concentration of 400 g/DM
.
Calcium chloride according to normative-technical documentation.
Askara on the other 6−09−4128.
Engeron on the other 6−09−3880.
Potassium sulfate according to GOST 4145.
Sulfuric acid according to GOST 4204.
Hydrochloric acid according to GOST 3118.
The soluble starch according to GOST 10163, solution with mass concentration of 0.5 g/DM: 0.5 g of soluble starch was mixed with 50 cm
of cold water. The resulting suspension is poured into a beaker containing 950 cm
of boiling water, add 10 cm
of hydrochloric acid and boil for 2−3 min. After cooling, add a solution of iodide of potassium Iodate to obtain a pale-blue color of the solution and stirred.
Potassium iodide-Iodate titrated solutions.
Solution a: 0,1110 g odnomodovogo potassium, 15 g of potassium iodide and 0.4 g of potassium hydroxide were placed in a glass with a capacity of 250 cm, and dissolved in 100 cm
of water. The solution was transferred to a volumetric flask with a capacity of 1 DM
, made up to the mark with water and mix.
Solution store in a dark bottle.
1 cmof solution A corresponds to approximately 0,00005 g of sulfur.
Solution B: 100 cmof solution A is placed in a volumetric flask with a capacity of 500 cm
, is diluted to the mark with water and mix.
1 cmof solution B corresponds to approximately 0,00001 g of sulfur.
The mass concentration of a solution of iodide of potassium Iodate set by standard samples with known mass fraction of sulphur, a close chemical composition to the analyzed samples.
The mass concentration of a solution of iodide of potassium Iodate (), g/cm
, is calculated by the formula
where — mass fraction of sulfur in the standard sample, %;
— weight of standard sample, g;
the volume of the solution of iodide of potassium Iodate consumed for titration of sample, standard sample, cm
;
the volume of the solution of iodide of potassium Iodate consumed for titration in the implementation of control experience, cm
.
The beach: a mixture of copper oxide, calcined at a temperature of (800±20) °C for 3−4 h, and iron, taken in the ratio (2:1); vanadium pentoxide is on the other 6−09−1948, calcined at a temperature of 400−450 °C for 3−4 h. it is allowed the use of other flooded areas.
The ethyl ether acetic acid according to GOST 22300 or ethyl alcohol according to GOST 18300.
4.3. Preparation for assay
4.3.1. Before testing check the completeness of burnout of sulfur from the refractory tube.
The absorption vessel and the vessel is filled up to compare height with a solution of starch, colored iodide with potassium Iodate to light blue color. Through the absorption vessel is passed a stream of oxygen. If after 4−5 min. the solution is colorless, add iodide-potassium Iodate until the light-blue color and once again allow oxygen. Color stability of the absorption vessel means complete burnout of sulfur from the tube.
4.3.2. Check the installation for leaks. To do this, in the heated to operating temperature mullite tube oxygen flow in a closed two-way tap 11. Consider installing tight, if wash vial 3 after some time will stop the appearance of gas bubbles. Otherwise, setup, disassemble, test glass joints, taps, lubricate them with petroleum jelly, assemble the system and again check for leaks.
4.4. Analysis
4.4.1. In a porcelain boat is placed a portion of the alloy of 0.5−1.0 g, if necessary, washed with ether or alcohol and 1.5 g of a mixture copper oxide and iron (when using a vanadium pentoxide linkage flux is 0.4 g).
The absorption vessel and the vessel comparison filled with a solution of starch, stained with a solution of iodide of potassium Iodate to pale blue.
A boat with suspension of sample and flux was placed in the most heated zone of the tube.
When the valve is closed 7 and 11 (see the devil.1) the tube is closed with a rubber stopper (or stopper). Then gently open the valve 7 for feeding oxygen into the furnace and kept the sample under the pressure of the gas 20, and then open the valve 11 and flow the gas flow through the absorption solution. To control the feed rate of oxygen use gas meter or a rheometer, and support oxygen flow rate of 1−1. 5 DM/min.
When the sulfur dioxide coming from the furnace in the absorption solution, it begins to discolor the bottom layer of liquid from the burette is added dropwise a solution of iodide of potassium Iodate with such speed that the liquid always remained a pale blue. The titration is complete, if the intensity of colour in solution in both vessels is the same and does not change for 1 min.
For complete combustion of the sample, the oxygen serves for 1 more min. If the color intensity of the absorption vessel is not reduced, the analysis is complete.
4.4.2. To carry out control experience in the boat placed a portion of the beach, and perform analyses in accordance with clause
4.5. Processing of the results
Mass fraction of sulfur () in percent is calculated by the formula
where is the mass concentration of the solution of iodide of potassium Iodate sulphur, g/cm
;
the volume of the solution of iodide of potassium Iodate consumed for titration, cm
;
the volume of the solution of iodide of potassium Iodate consumed for titration of the control experience, cm
;
— weight of charge, g
.
4.6. Norms of accuracy and norms of accuracy control in the determination of sulphur mass fraction given in the table.
