GOST 22536.2-87

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  ГОСТ 22536.2-87

GOST 22536.2−87 (ST SEV 5283−85) carbon Steel and unalloyed cast iron. Methods for the determination of sulphur (Change No. 1)

GOST 22536.2−87
(ST CMEA 5283−85)

Group B09

STATE STANDARD OF THE USSR

CARBON STEEL AND UNALLOYED CAST IRON

Methods of determining sulphur

Carbon steel and unalloyed cast iron.
Methods for determination of sulphur

AXTU 0809

Valid from 01.01.88
to 01.01.98*
______________________________
* Expiration removed
Protocol N 7−95 Interstate Council
for standardization, Metrology and certification.
(IUS N 11, 1995). — Note the manufacturer’s database.

INFORMATION DATA

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

PERFORMERS

D. K. Nesterov, PhD. tech. Sciences; S. I. Rudyuk, PhD. tech. Sciences, N.N. Gritsenko, PhD. chem. Sciences (head of subject); V. F. Kovalenko, PhD. tech. Sciences; S. V. Spirina, PhD. chem. Sciences (head of subject); O. M. Kirzhner

2. APPROVED AND put INTO EFFECT by decision of the USSR State Committee for standards from 20.02.87 N 301

3. The standard complies ST SEV 5283−85 in terms of its distribution in carbon steel and unalloyed cast iron

4. REPLACE GOST 22536.2−77

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. REPRINTING. December, 1987

The Change No. 1 approved by resolution of Gosstandart of the USSR from 28.03.90 No. 659, introduced with effect from 01.10.90 and published in IMS No. 6, 1990

The change made by the manufacturer of the database in the text IUS N 6, 1990


This standard establishes titrimetric, coulometric methods and the method of infrared spectroscopy for the determination of sulfur in carbon steel and unalloyed cast iron with the mass fraction of from 0.002 to 0.40%.

(Changed edition, Rev. N 1).

1. GENERAL REQUIREMENTS

1.1. General requirements for methods of analysis GOST 22536.0−87.

2. TITRIMETRIC METHOD

2.1. The essence of the method

The method is based on the combustion of the sample the sample in flowing oxygen at a temperature of 1250−1350°C, the absorption of sulfur dioxide water and titration of the resulting sulfurous acid solution of a mixture odnomodovogo and potassium iodide or with a solution of iodine in presence of starch indicator.

2.2. Equipment and reagents

Setting for titration for the determination of sulfur (hell. 1), consisting of an oxygen tank or coloradobased 1, equipped with a pressure reducing valve and pressure gauge for starting and regulating the current of oxygen; a gas washing bottle 2containing a solution of potassium permanganate with a mass concentration of 40 g/lsolution of potassium hydroxide with a mass concentration of 400 g/DM; Tischenko flask with concentrated sulphuric acid 3, V-shaped tube 4filled with anhydrous calcium chloride or angerona (allowed to carry out dry cleaning of oxygen; it is bells 2, 3, 4 use gorkaltseva tube, the column Astarita and a V-shaped tube, containing the first half (downstream) asbestos impregnated with duoxide of manganese, the second — anhydro); flowmeter for flow measurement of oxygen 5; a horizontal tubular furnace with silicafume heaters, providing heating of 1250−1350°C in 6; the controller 7, which maintain constant temperature furnace; voltage regulator 8 (which is allowed to use other types of kilns that provides the required temperature); refractory mullite tube 9 according to normative-technical documentation intended for the combustion of the sample, a length of 600−800 mm, with an inner diameter of 20−22 mm. the ends of the tube should protrude out of the oven at least 200 mm on each side (the tube is closed by a metal gate or a well-fitting rubber stoppers with holes and metal tips, to prevent erosion of the tubes. In hole insert glass tubes or brass pipe. Before use, the calcined porcelain tube over the entire length of the furnace at operating temperature); pumps porcelain GOST 9147−80 10 designed for the combustion of the sample, can withstand temperatures of 1350 °C (before use, the boat is calcined in flowing oxygen at operating temperature and store it in a desiccator, ground joint lid which must not be covered by lubricating substance); filter 11 for absorbing solid oxides, produced during combustion of the test portion and carried by a current of oxygen from the furnace (the filter is a glass spherical or cylindrical vessel filled with glass or cotton wool); microburette 12 or burette with a capacity of 25 cm, containing a solution of iodide of potassium Iodate or iodine solution; absorption vessel 13 with a height of 250−265 mm and a diameter of 30−35 mm; vessel for solution comparisons 14 height 250−265 mm and a diameter of 30−35 mm. the Diagram of the cell consisting of the absorption vessel and vessel comparisons given on features. 2. In the absorption vessel is soldered l-shaped glass tube with a diameter of 7 mm, terminating in a bubbler with a float 15 (see the devil. 1), through which the absorption vessel receives the gaseous products of combustion. The absorption vessel is in the process of absorption and titration dioxide sulfur in the vessel comparison, is solution comparisons to control the color of the solution during titration. Allowed to use the cell in another form and without the vessel of the comparison.

Damn. 1. Setting for titration for the determination of sulfur

Damn. 1

Damn. 2. Diagram of a cell, consisting of the absorption vessel and vessel comparison

Damn. 2

Electric type SNOL according to normative-technical documentation, providing a heating temperature not lower than 1000 °C. a Hook with which the boat is introduced into the tube for flaring and recovered from it, made of heat-resistant low-carbon wire with a diameter of 3−5 mm and a length of 500−600 mm.

The oxygen purity not less than 99% according to GOST 5583−78.

Hydrochloric acid by the GOST 3118−77 or GOST 14261−77.

Sulfuric acid GOST 4204−77 or GOST 14262−78.

Potassium hydroxide according to GOST 9286−82 or sodium hydroxide according to GOST 4328−77.

Potassium permanganate according to GOST 20490−75, a solution with a mass concentration of 40 g/lsolution of potassium hydroxide with a mass concentration of 400 g/DM.

Calcium chloride according to normative-technical documentation.

Soda lime or soda asbestos (Askari).

The rate of anhydrous magnesium (anhydro) MD (СlO).

The soluble starch according to GOST 10163−76.

A solution with a mass concentration of 0.5 g/l(used in the titration of a solution of a mixture of potassium iodide and odnomodovogo): 0.5 g of soluble starch triturated in a porcelain mortar with 50 cmof water and pour the slurry in a thin stream at 950 cm. of boiling water. To the obtained solution poured 15 cmof hydrochloric acid, cooled and poured in small portions with stirring a solution of iodide of potassium Iodate to obtain a weak blue color of the solution.

A solution with a mass concentration of 1 g/DM(used in the titration with iodine solution); 1 g soluble starch triturated in a porcelain mortar with 50 cmof water and pour the slurry in a thin stream at 950 cmof boiling water, add two drops of hydrochloric acid and boil the solution for 5 min, cooled and poured in small portions with stirring a solution of iodine to obtain a weak blue color of the solution.

Potassium ignominously according to GOST 4202−75;

Potassium iodide according to GOST 4232−74.

A standard solution of potassium odnomodovogo; 0,0862 g odnomodovogo potassium, 17.0 g of potassium iodide and 0.4 g of potassium hydroxide dissolved in water and bring the solution volume up to 1 DM. The solution was stored in a flask made of dark glass. When determining the mass fraction of sulfur less than 0.01% to the initial solution odnomodovogo potassium diluted in the ratio 1:4 or 1:6.

Iodine crystal according to GOST 4159−79 standard solution; 1,9845 g of iodine is dissolved with 15 g of potassium iodide in 60 cmof water in the flask with a ground stopper. After complete dissolution of the iodine solution is poured into a bottle made of dark glass, dilute with water to volume of 5 DMand mix well.

Mass concentration of solution odnomodovogo potassium or iodine set by standard samples with known mass fraction of sulfur and a chemical composition close to the composition of the sample. The burning of batches of standard samples carried out in the same conditions as the analysis. The mass concentration expressed in grams of sulfur per 1 cmof a solution, calculated by the formula

,

where  — mass fraction of sulfur in the standard sample, %;

 — weight of standard sample, g;

the volume of the solution odnomodovogo potassium or iodine used for the titration of a solution of a standard sample, cm;

the volume of the solution odnomodovogo potassium or iodine used for the titration of a solution of a control sample, cm.

Marshes: tin GOST 860−75 or copper according to GOST 546−79 in the form of chips, as well as oxides of these metals, pre-checked in analysis for sulfur content. Allowed to use other marshes. All marshes should be checked for sulphur content, which must not exceed the value of permissible differences for the corresponding values of the mass fraction of sulphur, are given in table. 1.

Manganese dioxide according to GOST 4470−79.

The ethyl ether according to GOST 22300−76.

The technical rectified ethyl alcohol GOST 18300−87.

Acetone according to GOST 2603−79.

(Changed edition, Rev. N 1).

2.3. Preparation for assay

Before starting, heat the oven to the desired temperature and check the installation for leaks.

The completeness of burning sulfur from porcelain pipes and pumps is determined as follows: upon reaching a furnace temperature of 1250−1350°C the tube is closed on both sides by tubes, are poured into both vessels at 110−120 cmof starch solution weak blue color, turning the tap on, passed a current of oxygen at the rate of 2.5 DM/min.

Discoloration of the solution in the absorption vessel by passing oxygen for several minutes indicates the allocation of the recovery tube of gaseous substances that react with iodine. Without stopping the flow of oxygen, absorbing poured to the solution a standard solution of iodine or of a mixture of potassium iodide and odnomodovogo as long as the color intensity of the solutions in both vessels will not be the same. To check the correct operation of the installation burn 2−3 sample standard sample of steel or iron in the presence of a flux as specified in claim 2.4. Then burn the flux linkage for the establishment of amendments in the reference experiment. Before starting work, after changing the porcelain tubes to burn for two-three random sample of the metal.

2.4. Analysis

The weight and steel (cast iron), if necessary, washed with ether, with ethyl alcohol or acetone and dried, a mass of 0.5−1.0 g was placed in a boat, evenly distributed over the bottom and covering with a layer of flux in an amount of 0.5−1.0 g in the analysis of the carbon steel is allowed to hold without burning the flux. The boat with the sample and flux with a hook placed in the most heated portion of the porcelain tube and quickly close the tube with a rubber stopper or stopper in which is inserted a glass or brass tube for supplying oxygen. Burn weighed sample at a temperature of 1250−1350°C. the Rate of oxygen transmission is 2.5 DM/min.

In the combustion process of the sample to observe the color change of the liquid in the absorption vessel, where the absorption of sulfur oxides. During the combustion of the coating solution in the absorption vessel should be close to the color of the solution comparison. For this to the solution in the absorption vessel by decreasing the intensity of the color added to a solution of iodide of potassium Iodate or iodine to obtain the same color intensity in both vessels. The titration is complete when the color intensity of the solutions in both vessels are equal. To verify the completeness of combustion of sample oxygen continue to serve for another 1 min. If the color intensity of the solution is reduced, the determination is complete, if you decrease the titration continue. After combustion of the sample boat hook is removed from the oven. Molten oxides should be dense, homogeneous mass located around the bottom of the boat. Otherwise, take a new sample and repeat the burning. The absorption solution is decanted from the vessel and wash vessel with water.

After about 20 burns tube through which the gases are supplied into the absorption vessel and pipes for the combustion should be cleaned of iron oxides ruff of soft wire.

Not allowed to use the intoxicated tubes, as this may lead to underestimated results. Overestimated results may be obtained with insufficient preliminary calcination tube and the boat, and when erosion of the tubes.

(Changed edition, Rev. N 1).

2.5. Processing of the results

2.5.1. Mass fraction of sulfur in percent is calculated by the formula

,

where  — volume of the solution odnomodovogo potassium or iodine used for the titration of a solution of the test sample, cm;

the volume of the solution odnomodovogo potassium or iodine used for the titration of a solution in the reference experiment, cm;

 — mass concentration of the solution odnomodovogo potassium or iodine, g/cmsulphur;

 — weight of sample, g

.

2.6. Norms of accuracy and norms of accuracy control of determination of sulphur mass fraction for steel are given in table. 1, for iron — table. 2.

Table 1

Table 2

(Changed edition, Rev. N 1).

3. COULOMETRIC METHOD

3.1. The essence of the method

The method is based on the combustion of the sample the sample in flowing oxygen at a temperature of 1250−1350°C, the absorption of the formed sulphur dioxide absorption solution with a particular initial pH value and subsequent measurement in the apparatus for coulometric titration, is necessary to restore the original pH value of the amount of electricity that is proportional to the sulfur content in the sample sample.

3.2. Equipment and reagents

Coulometric installation of any type complete with all accessories (comonomer, absorption vessels, pH meter, corrector mass) for the precision of the analyses specified in the table.

Horizontal tubular oven with silicafume heaters, ensure the temperature of 1250−1350°C.

Oxygen tank or coloradobased.

Tube refractory mullite according to normative-technical documentation with a length of 600−800 mm, with an inner diameter of 20−22 mm.

Boat porcelain with GOST 9147−80.

Electric type SNOL according to normative-technical documentation, providing a heating temperature not lower than 1000 °C.

Before use, the boat is calcined in flowing oxygen at operating temperature and store it in a desiccator, ground joint lid which must not be covered by lubricating substance.

Absorption and support the solutions prepared in accordance with the type of the used coulometric setup.

Marshes: pjatiokisi vanadium according to normative-technical documentation;

copper GOST 546−79, tin GOST 860−75, iron carbonyl for Radiotechnical GOST 13610−79 or carbonyl iron OS.h. Allowed to use other marshes. Mass fraction of sulphur in the flux should not exceed the value allowable absolute differences for the respective concentration ranges given in the table.

The technical rectified ethyl alcohol GOST 18300−87.

The ethyl ether according to GOST 22300−76.

Acetone according to GOST 2603−79.

(Changed edition, Rev. N 1).

3.3. Analysis

The device is ready to work in accordance with the instructions. To remove traces of sulfur from the unit before starting the analysis through the installation of leak current of oxygen and calcined up. The transmission of oxygen and the calcining tube is carried out to obtain the minimum continuous readings.

To control the correct operation of the unit before starting work and after every 2−3 hours while you work burn two or three sample standard sample of steel or cast iron with a known mass fraction of sulphur, close to define.

Weighed samples of ground mounted depending on the type of coulometric setup, placed in a porcelain boat and covered with a uniform layer of flux. The mass ratio of the batches of flux and sample is 1:1 or 2:1.

A boat with linkage and flux is placed in the working part of the furnace and burning the sample at a temperature of 1250−1350°C.

The analysis is complete, if the readings or the meter does not change for 1 min or change the amount of idle accounts tool.

3.4. Processing of the results

3.4.1. Mass fraction of sulfur in percent is calculated by the formula

,

where  — reading digital display of the device, the resulting combustion of the sample of the sample, %;

 — the arithmetic average of the readings of the digital display device, resulting from the burning flux at carrying out of control tests, %.

3.4.2. Norms of accuracy and norms of accuracy control of determination of sulphur mass fraction for steel are given in table. 1, for iron in table. 2.

(Changed edition, Rev. N 1).

4. THE METHOD OF INFRARED SPECTROSCOPY

4.1. The essence of the method

The method is based on the combustion of the sample the sample in flowing oxygen at a temperature of 1350−1700°C and determining the quantity of the formed sulfur dioxide by measuring the absorbed infrared radiation to them.

4.2. Equipment and reagents

Automatic analyzer based on absorption of infrared radiation of any type with all accessories.

The flux and ancillary materials depending on the type of the used analyzer.

4.3. Analysis

The analysis is conducted depending on the type of analyzer.

4.4. Processing of the results

4.4.1. Mass fraction of sulfur in percent is determined by digital signal analyzer minus the result of the reference experiment.

4.4.2. Norms of accuracy and norms of accuracy control of determination of sulphur mass fraction for steel are given in table. 1, for iron in table. 2.

(Changed edition, Rev. N 1).