SU730455A1 - Boiling intensifier - Google Patents

Description

(54) BOILING INTENSIFICATOR The invention relates to metallurgy, mainly to three-way casting of boiling steel, in the process of which intensifiers are used. Intensifiers are known that contain scale, fluorspar, and soda 1 as a base. However, these intensifiers do not sufficiently regulate the surface tension of the liquid steel and are not sufficiently fluid. The closest technical solution is an intensifier 2, which contains: Rolled dross 82-84 Plasma spar 5-7 Sodium nitrate 10-12 The intensifier allows to obtain an ingot outer crust thickness of at least 15 mm. The sodium nitrate, which is part of the intensifier, absorbs oxygen free and thereby contributes to the activation of oxidation and hydration processes. However, the scale containing in an amount possessing a quantity does not allow regulating the surface tension of the liquid steel, since the oxidation of carbon, gas formation, crystallization, necessitates the addition of fluorspar for slagging. Fluorspar (CaF) at first provides a reduction in the melting temperature. The slag-forming phase melts at a temperature of about 1200 s, while the liquid steel is heated to a temperature higher. Under these conditions, CaF rapidly decomposes with the release of fluoride vapors, thus forming refractory calcium oxides, and liquid mobility decreases. The degree of removal of slag impurities from the metal deteriorates. The gas bubbles contained in them are retarded, which also reduces the boiling activity of the metal. Moreover, the occurring volatile fluoride compounds worsen the working conditions of the maintenance personnel. The purpose of the invention is to ensure the high quality of the cast metal due to its low melting point and liquid mobility; the mixture. This goal is achieved by the fact that the mixture additionally contains a silicate lump in the following ratio of components:

Silicate lump 60-63 Sodium nitrate 10-11 Iron oxides Else The ratio of the intensifier is in accordance with the silica-iron oxide system sodium oxide and the toxic diagram of the sodium metasilicate sodium-iron oxide (). According to this system, the most low-melting composition of the intensifier corresponds to the melting point of 825-850 ° C. Upon contact of the mixture with the molten metal, a liquid-mobile slag phase appears, 5Naj, 0Fe20g 6SiOg - a ternary compound, characterized by a congruent melting equilibrium.

The use of a mixture of the proposed composition when casting boiling steel into molds will not entail an increase in silicate inclusions in the ingot, since A new boiling intensifier provides more vigorous stirring at energetic boiling, as a result, favorable conditions are created for the Redistribution of solids, as well as for the formation, coagulation and removal of nonmetallic inclusions. Thanks to a relatively low melting point, we offer: big difference between these parameters

and the temperature of the process of crystallization of the metal.

In most cases, for a boiling metal, the liquidus line is close to the level. The achievement of such a difference, with all other unchanged physico-chemical conditions and their duration, leads to the completion of the process of cleaning the metal from silicate and other inclusions, both in the liquid and in the solid state. Due to the fluid, dynamically stable fraction, which displaces the metal in its liquid inclusion and later from the solid-liquid zone of its hyalatonic solution, the metal is completely cleaned. The silicates, which may additionally form from the components of the introduced intensifier, will also undergo coagulation and be brought to the head of the ingot in contact with other particles.

Sulfur and phosphorus (in the form of sodium sulfides, volatile feed monosulphides) are also removed from the main part of the ingot as a result of interaction with sodium silicates and the formation of phosphates in the presence of ferrous oxide in boiling metal.

The table shows some

Q mixture compositions and data on the influence on the quality of the ingot.

60

29

63

27

61.5

28

For the preparation of an intensifier, rolled or forged scale is used as iron oxides. The iron scale and silicate lump are crushed to fractions of no more than 3 mm, and the sodium silicate is up to 2 mm.

The application of the proposed composition of the intensifier eliminates contamination. Good surface quality.

Ready flaws, cracks are eliminated.

Also

The environment is hazardous fumes, which makes it easy to melt, vkot and fluid mobility, which improves the quality of the smelted metal.

Claims (2)

Invention Formula A boiling intensifier containing iron oxides and sodium chloride 57 RU, characterized in that. that, in order to ensure the high quality of the cast metal due to the low melting and liquid mobility of the mixture, it additionally contains a silicate lump at the following ratio of components: Silicate lump 60-63 Sodium nitrate 10-And iron oxides Else Sources of information taken into account during examination 1 .Sivtsov G. Application of boiling point distillers during casting. Metallurg 1967, 1, p. 20.1967. 2. Authors certificate of the USSR About 212297, class, B 22 D 7/00, 1966.