GOST 22974.12-96

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  ГОСТ 22974.12-96

GOST 22974.12−96 fused welding Fluxes. Method for the determination of sulfur

GOST 22974.12−96

Group B09

INTERSTATE STANDARD

FUSED WELDING FLUXES

Method for the determination of sulfur

Melted welding fluxes.
Method of sulphur determination

ISS 77.040
AXTU 0809

Date of implementation 2000−01−01

Preface

1 DEVELOPED by the Interstate technical Committee for standardization MTK 72; the Institute of electric them. E. O. Paton of NAS of Ukraine

SUBMITTED to the State Committee of Ukraine for standardization, Metrology and certification

2 ADOPTED by the Interstate Council for standardization, Metrology and certification (Protocol No. 9 dated April 12, 1996)

The adoption voted:

3 Resolution of the State Committee of the Russian Federation for standardization and Metrology, dated April 21, 1999 N 134 inter-state standard GOST 22974.12−96 introduced directly as state standard of the Russian Federation from January 1, 2000

4 REPLACE GOST 22974.12−85

1 Scope

This standard specifies the titrimetric method for the determination of sulfur at a content of from 0.02 to 0.2%.

2 Normative references

The present standard features references to the following standards:

GOST 4202−75 Potassium ignominously. Specifications

GOST 4204−77 sulfuric Acid. Specifications

GOST 4232−74 Potassium iodide. Specifications

GOST 5583−78 Oxygen gas technical and medical. Specifications

GOST 6259−75 Glycerin. Specifications

GOST 9147−80 Glassware and equipment lab porcelain. Specifications

GOST 10163−76 Starch soluble. Specifications

GOST 20490−75 Potassium permanganate. Specifications

GOST 22974.0−96 fused welding Fluxes. General requirements for methods of analysis

GOST 24363−80 Potassium hydroxide. Specifications

3 General requirements

General requirements for methods of analysis GOST 22974.0.

4 Titrimetric method for the determination of sulfur

4.1 the essence of the method

The method consists in burning the flux in a current of oxygen at a temperature of 1250−1350 °C. the Formed sulfur dioxide is absorbed in an absorption vessel with water, forming sulfurous acid, which octarepeat yodit solution of potassium Iodate in the presence of starch (indicator).

4.2 Equipment, reagents and solutions

Setup for the determination of sulfur (figure 1).

Figure 1 — Installation for determination of sulfur

1 — oxygen cylinder according to GOST 5583 with reducing valve; 2 — flask Tishchenko,
containing a solution of potassium permanganate mass concentration of 0.04 g/cmin the solution
potassium hydroxide mass concentration of 0.4 g/cm; 3 — drying column filled
calcium chloride; 4 — tube furnace with SIC-heater; 5 — porcelain
(high-alumina) tube with a length of 750−800 mm and an inner diameter of 20−26 mm;
6 — vessel for titration; 7 — container for comparison; 8 — burette

Figure 1 — Installation for determination of sulfur

Porcelain tubes and pumps N 2 according to GOST 9147, calcined in flowing oxygen at operating temperature.

The hook with which the boat was placed in a tube and extracted from it, is made of heat-resistant wire with a diameter of 3−5 mm, length 500−600 mm.

Sulfuric acid according to GOST 4204.

Potassium hydroxide according to GOST 24363 and the solution of the mass concentration of 0.4 g/cm.

Potassium iodide according to GOST 4232.

Potassium ignominously according to GOST 4202.

Potassium permanganate according to GOST 20490, solution mass concentration of 0.04 g/cm.

The calcium chloride.

Glycerin according to GOST 6259.

The soluble starch according to GOST 10163.

Solution a: 16 g of starch was dissolved with heating in 1000 cmof water. To the obtained solution poured 1000 cmof glycerin and mix well, store in a dark place.

Solution B: 50 cmsolution A and 20 cmof sulphuric acid are dissolved in 4000 cmof distilled water and mix thoroughly, this solution goes directly to the determination of sulfur.

Titrated solution for the determination of sulfur: 0.05 g odnomodovogo potassium, 10 g of potassium iodide and 0.2 g of potassium hydroxide dissolved in a volumetric flask with a capacity of 1000 cmof water and bring to mark.

The mass concentration of the solution of iodide of potassium odnomodovogo set according to the standard model of the flux with a known sulphur content. The analysis of the standard sample carried out under the same conditions as the analysis of the investigated sample.

The mass concentration of the solution of iodide of potassium odnomodovogo , g/cmsulphur, calculated by the formula

, (1)

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

 — the weight of the portion of the flux standard sample, g;

the volume of the solution of iodide of potassium odnomodovogo, spent on titration, sm.

4.3 Preparation for analysis

Before starting, heat the oven to a temperature 1250−1300 °C and check the installation for leaks.

For this purpose in the absorption vessel and the vessel comparison pour 70−80 cmof starch solution B, add a few drops of the titrated solution of potassium odnomodovogo until the light-blue color and open the tap, allow oxygen with such speed that the liquid level of the absorber has risen by 30−40 mm. Then close the oxygen absorption vessel (with a clamp) and check the installation for leaks. The installation is sealed, if the absorption bottle after some time will stop the appearance of gas bubbles. Before burning of the sample or standard sample to a porcelain tube tested for the presence of reductive substances.

If the stain in the absorption vessel disappears, then add titrated solution of iodide of potassium to odnomodovogo until the pale blue color of the solution no longer changes.

4.4 analysis

Weighed flux of mass 1 g is placed in a porcelain boat. A boat with a hook is introduced into the hottest part of the porcelain tube and tightly stoppered. Open the faucet and allow oxygen with the rate at which the level of liquid in the absorption vessel rises to 30−40 mm.

When leaving the furnace in the absorption vessel, the gases will begin to discolor the solution from the burette pour the titrated solution of iodide of potassium odnomodovogo with the speed in which the blue color does not disappear during burning.

The titration is complete when the color intensity in both vessels is the same. After that allow oxygen in for 1−3 minutes, If the color intensity is not reduced, the definition is complete.

4.5 Processing of results

4.5.1 Mass fraction of sulfur , %, is calculated by the formula

, (2)

where  — volume of the solution of iodide of potassium odnomodovogo consumed for titration of a solution of test sample, cm;

 — mass concentration of a solution of iodide of potassium odnomodovogo, g/cmsulphur;

 — the weight of the portion of the flux,

4.5.2 Standards of accuracy and standards of accuracy control of determination of sulphur mass fraction are given in table 1.


Table 1

Percentage